Prof. Richard B. Hoover Profile

Prof. Richard B. Hoover

at Athens State Univ

SPIE Involvement:

Track Chair | Editor | Author

Publications (192)

Proceedings Article | 28 September 2015 Paper

Ocean in Enceladus enhances the case for Panspermia

Chandra Wickramasinghe, Milton Wainwright, Gensuke Tokoro, Richard Hoover

Proceedings Volume 9606, 96061R (2015) https://doi.org/10.1117/12.2222098

KEYWORDS: Water, Liquids, Comets, Solar system, Microorganisms, Organisms, Pluto, Saturn, Astrobiology, Bacteria

Read Abstract +

Proceedings Article | 25 September 2015 Paper

Evidence of ancient microbial activity on Mars

Jamie Wallis, N. Wickramasinghe, Daryl Wallis, Nori Miyake, M. Wallis, Richard Hoover

Proceedings Volume 9606, 96060V (2015) https://doi.org/10.1117/12.2186518

KEYWORDS: Pyrite, Arsenic, Iron, Minerals, Veins, Bacteria, Etching, Carbon, Scanning electron microscopy, Oxidation

Read Abstract +

Proceedings Article | 22 September 2015 Paper

Chemical and structural composition of organic carbonaceous structures in Tissint: evidence for a biogenetic origin

Jamie Wallis, N. Wickramasinghe, Daryl Wallis, Nori Miyake, M. Wallis, Richard Hoover

Proceedings Volume 9606, 96060L (2015) https://doi.org/10.1117/12.2186515

KEYWORDS: Raman spectroscopy, Carbon, Crystals, Organic materials, Spectroscopy, Pyrite, Chlorine, Gallium, Coating, Scanning electron microscopy

Read Abstract +

Proceedings Article | 22 September 2015 Paper

Carbonaceous structures in the Tissint Martian Meteorite: evidence of a biogenetic origin

Jamie Wallis, N. Wickramasinghe, Daryl Wallis, Nori Miyake, M. Wallis, Richard Hoover

Proceedings Volume 9606, 96060K (2015) https://doi.org/10.1117/12.2186507

KEYWORDS: Pyrite, Scanning electron microscopy, Crystals, Carbon, Photomicroscopy, Contamination, X-rays, Calcite, Backscatter, Minerals

Read Abstract +

Proceedings Article | 21 September 2015 Paper

Instruments and methods to search for extraterrestrial life

Richard Hoover

Proceedings Volume 9606, 96060N (2015) https://doi.org/10.1117/12.2192893

KEYWORDS: Mars, Microorganisms, Organisms, Comets, Lawrencium, Bacteria, Carbon, Liquids, Molecules, Planets

Read Abstract +

Is Life restricted to the Planet Earth? or Does life exist elsewhere in the Cosmos? The existence of extraterrestrial life is the fundamental question of Astrobiology. Detecting evidence for living organisms beyond our planet is even more difficult than finding fossilized remains of ancient organisms. Microbiological investigations during the past century have established the fundamental physical and chemical requirements and limits for life on Earth. It is now known that life requires only water, a source of energy, and a small suite of biogenic elements under a surprisingly wide range of environmental conditions. The discovery that microbial extremophiles live and grow over a very broad span of temperature, pH, salinity, pressure and radiation levels has greatly enhanced the possibility that life may be present on many bodies of our Solar System. Recent discoveries by Space Missions and Rovers have invalidated many long held paradigms regarding the distribution of water, organic chemicals and the possibility of life elsewhere in the Cosmos. This paper considers the discovery of water, ice and organics on distant planets, moons and comets and evidence for fossil organisms on Mars and in SNC and carbonaceous meteorites. Instruments and methods are considered for spectroscopy and fluorescence of biomolecules (e.g., photosynthetic pigments) for remote detection of conclusive evidence for extraterrestrial life. Optical Video Microscopy is discussed as a direct means for detecting extraterrestrial life using small visible light/UV video microscopes, with ample magnification to record motile bacteria and other living organisms in samples collected by Rovers or Landers. Locomotion of living cells of bacteria and other microbes requires great expenditure of energy and motile cells can be distinguished by video microscopy from the physico-chemical movements (by Brownian Motion, Diffusion or Current Drift) of dead cells, dust particles and abiotic mineral grains.

Proceedings Article | 11 September 2015 Paper

Molecular studies of anaerobic strains from Antarctica and their taxonomic identifications

Zhe Lyu, Elena Pikuta, Jacob Hagel, Genevieve LaBrake, Richard Hoover, William Whitman

Proceedings Volume 9606, 96060X (2015) https://doi.org/10.1117/12.2192787

KEYWORDS: Neodymium, Taxonomy, Microorganisms, Statistical analysis, Astrobiology, Databases, Particles, Standards development, Bioalcohols, Oceanography

Read Abstract +

We present phylogenetic analyses for four anaerobic bacterial isolates from samples collected in the Schirmacher Oasis and Lake Untersee in Antarctica. Near-full length of 16S rRNA genes were amplified from the four strains and sequenced for identification of their close relatives and their phylogenetic relationships. Strain A7P-90m shared a low 16S rRNA sequence identity of around 85% with its closest relatives within the Bacteroides phylum. This low level of sequence similarity suggests that it may represent a novel family within this phylum. The 16S rRNA sequence identity between strain LZ-22 and its closest relatives Granulicoccus phenolivorans and Propioniferax innocua within the Propionibacteriaceae family were 91.9% and 93.2%, respectively. This low level of sequence similarity suggests that it may represent a novel genus within this family. Strains 9G and ISLP-3 were closely related to known species of the genera Halolactibacillus and Sanguibacter, respectively. However, the 16S rRNA sequence identities between strains 9G and ISLP-3 and their close relatives were too high to make reliable taxonomic inferences (i.e., 99.9% between 9G and H. miurensis, and 98.6% between ISLP-3 and S. suaresii). Because the recA gene delivers higher resolution for taxonomic inferences than the 16S rRNA gene, the primers for conserved recA gene were designed for PCR amplification and sequencing from Halolactibacillus and Sanguibacter type strains. Strain 9G shared a recA sequence identity of 99.6% with its closest relative H. miurensis, suggesting that it is a subspecies. The recA sequence identity shared between strain ISLP-3 and its six closest relatives ranged from 85.9~90.2%. This result is consistent with this strain representing a novel species within the genus Sanguibacter. Based on the molecular study presented here and the phenotypic properties presented elsewhere, we propose that strain LZ-22 is a representative of a novel genus and species, with proposed names Raineyella antarctica gen. nov., sp. nov. Strain ISLP-3 is a representative of a novel species, Sanguibacter gelidistatuaria sp. nov. Strain A7p-90m may represent a novel family within the order Bacteroidales. Chemotaxonomic characterizations of these strains are underway to gather more evidence for the proposed classifications.

Proceedings Article | 11 September 2015 Paper

Microbiological investigation of two chondrite meteorites: Murchison and Polonnaruwa

Elena Pikuta, Zhe Lyu, William Whitman, Geneviev LaBrake, Jamie Wallis, Keerthi Wickramarathne, N. Chandra Wickramasinghe, Richard Hoover

Proceedings Volume 9606, 96060M (2015) https://doi.org/10.1117/12.2191203

KEYWORDS: Ultraviolet radiation, Minerals, Contamination, Nitrogen, Microscopy, Soil contamination, Microorganisms, Bacteria, Pluto, Hydrogen

Read Abstract +

Proceedings Article | 21 October 2014 Open Access

Microfossils and biomolecules in carbonaceous meteorites: implications to the possibility of life in water-bearing asteroids and comets

Richard Hoover

Proceedings Volume 9226, 922602 (2014) https://doi.org/10.1117/12.2065571

KEYWORDS: Nitrogen, Proteins, Molecules, Organisms, Carbon, Asteroids, Microorganisms, Chemical elements, Comets, Bacteria

Read Abstract +

It is well established that carbonaceous meteorites contain water, carbon, biogenic elements and a host of organic chemicals and biomolecules. Several independent lines of evidence indicate that the parent bodies of the CI1 and CM2 carbonaceous meteorites are most probably the C-type asteroids or cometary nuclei. Several of the protein amino acids detected in the meteorites exhibit chirality and have an excess of the L-enantiomer -- such as in the amino acids present in the proteins of all known life forms on Earth. Isotopic studies have established that the amino acids and nucleobases in the CI1 and CM2 carbonaceous meteorites are both indigenous and extraterrestrial. Optical and Scanning Electron Microscopy studies carried out by researchers during the past half century have revealed the presence of complex biogenic microstructures embedded in the rock-matrix of many of carbonaceous meteorites similar to extinct life-forms known as acritarchs and hystrichospheres. Carbonaceous meteorites also contain a wide variety of large filaments that exhibit the complex morphologies and correct size ranges of known genera and species of photosynthetic microorganisms such as cyanobacteria and diatoms. However, EDAX investigations have shown that these carbon-rich filaments typically have nitrogen content below the level of detection (<0.5% atomic) of the instrument. EDAX studies of living and dead terrestrial biological materials have shown that nitrogen can be detected in ancient mummies and tissue, hair and teeth of Pleistocene Mammoths. Hence, the absence of detectable nitrogen in the filaments provides direct evidence that they do not represent recent biological contaminants that invaded these meteorite stones after they were observed to fall to Earth. The spectral and fluorescence properties of pigments found in several species of terrestrial cyanobacteria which are similar to some microfossils found in carbonaceous meteorites may provide valuable clues to help search for evidence for biomolecules and life on the icy moons of Jupiter and Saturn, asteroids and comets.

DOWNLOAD PAPER

Proceedings Article | 3 October 2013 Paper

Acritarchs in carbonaceous meteorites and terrestrial rocks

Alexei Rozanov, Richard Hoover

Proceedings Volume 8865, 886507 (2013) https://doi.org/10.1117/12.2029608

KEYWORDS: Scanning electron microscopy, Electron microscopes, Gallium, Spine, Spherical lenses, Carbon, Nitrogen, Minerals, Astrobiology, Binary data

Read Abstract +

Proceedings Article | 26 September 2013 Open Access

Memorial tribute to astrobiology pioneers Dr. David S. Mckay and academician Georgy A. Zavarzin

Alexei Rozanov, Sergei Rozhnov, Elena Pikuta, Richard Hoover

Proceedings Volume 8865, 886502 (2013) https://doi.org/10.1117/12.2029404

KEYWORDS: Astrobiology, Mars, Bacteria, Microbiology, Microorganisms, Crystals, Geology, Chemical analysis, Planetary science, Scanning electron microscopy

Read Abstract +

DOWNLOAD PAPER

Proceedings Article | 26 September 2013 Paper

Some unique features of alkaliphilic anaerobes

Erin Roof, Elena Pikuta, Christopher Otto, George Williams, Richard Hoover

Proceedings Volume 8865, 88650F (2013) https://doi.org/10.1117/12.2045350

KEYWORDS: Bacteria, Hydrogen, Organisms, Carbon, Yeast, Sodium, Molecules, Bioalcohols, Microorganisms, Ions

Read Abstract +

Proceedings Article | 26 September 2013 Paper

Fossilized diatoms in meteorites from recent falls in Sri Lanka

Richard Hoover, Jamie Wallis, Keerthi Wickramarathne, Anil Samaranayake, George Williams, Gregory Jerman, D. Wallis, N. Wickramasinghe

Proceedings Volume 8865, 886506 (2013) https://doi.org/10.1117/12.2028605

KEYWORDS: Oceanography, Comets, Water, Ocean optics, Scanning electron microscopy, Silica, Spine, Minerals, Magnetic resonance imaging, Microorganisms

Read Abstract +

Proceedings Article | 26 September 2013 Paper

Physical, chemical, and mineral properties of the Polonnaruwa stones

Jamie Wallis, N. Wickramasinghe, Daryl Wallis, Nori Miyake, M. Wallis, Richard Hoover, Anil Samaranayake, Keerthi Wickramarathne, Anthony Oldroyd

Proceedings Volume 8865, 886508 (2013) https://doi.org/10.1117/12.2029607

KEYWORDS: Glasses, Silica, Crystals, Quartz, Oxygen, Statistical analysis, Minerals, Scanning electron microscopy, Absorption, Titanium dioxide

Read Abstract +

We report on the physical, chemical and mineral properties of a series of stone fragments recovered from the North Central Province of Sri Lanka following a witnessed fireball event on 29 December 2012. The stones exhibit highly porous poikilitic textures comprising of isotropic silica-rich/plagioclase-like hosts. Inclusions range in size and shape from mm-sized to smaller subangular grains frequently more fractured than the surrounding host and include ilmenite, olivine (fayalitic), quartz and accessory zircon. Bulk mineral compositions include accessory cristobalite, hercynite, anorthite, wuestite, albite, anorthoclase and the high pressure olivine polymorph wadsleyite, suggesting previous endurance of a shock pressure of ~20 GPa. Further evidence of shock is confirmed by the conversion of all plagioclase to maskelynite. Here the infrared absorption spectra in the region 580 cm^-1 to 380 cm^-1 due to the Si-O-Si or Si-O-Al absorption band shows a partial shift in the peak at 380 cm^-1 towards 480 cm^-1 indicating an intermediate position between crystalline and amorphous phase. Host matrix chemical compositions vary between samples, but all are rich in SiO₂. Silica-rich melts display a heterogeneous K-enrichment comparable to that reported in a range of non-terrestrial material from rare iron meteorites to LL chondritic breccias and Lunar granites. Bulk chemical compositions of plagioclase-like samples are comparable to reported data e.g. Miller Ranger 05035 (Lunar), while Si-rich samples accord well with mafic and felsic glasses reported in NWA 1664 (Howardite) as well as data for fusion crust present in a variety of meteoritic samples. Triple oxygen isotope results show Δ¹⁷O = -0.335 with δ¹⁸O (‰ rel. SMOW) values of 17.816 ± 0.100 and compare well with those of known CI chondrites and are within the range of CI-like (Meta-C) chondrites. Rare earth elemental abundances show a profound Europium anomaly of between 0.7 and 0.9 ppm while CI normalized REE patterns accord well with those of high potassium and high aluminium glasses found in lunar and 4 Vesta samples. Twoelement discrimination maps of FeO vs SiO₂, FeO vs TiO₂, FeO vs Al₂O₃ and FeO vs Na₂O similarly match those of impact glasses present in lunar samples and remain within relatively close proximity of the KREEP component. Iridium levels of between 1-7ppm, approximately 104 times that of terrestrial crustal rocks, were detected in all samples.

Proceedings Article | 26 September 2013 Paper

Perchlorates are compatible with life on Earth: Why not Mars?

Vera Kolb, Richard Hoover

Proceedings Volume 8865, 886504 (2013) https://doi.org/10.1117/12.2029402

KEYWORDS: Mars, Bacteria, Organisms, Natural surfaces, Carbon, Oxygen, Chlorine, Contamination, Microorganisms, Oxidation

Read Abstract +

Proceedings Article | 13 November 2012 Paper

Microfossils, biomolecules and biominerals in carbonaceous meteorites: implications to the origin of life

Richard Hoover

Proceedings Volume 8521, 852106 (2012) https://doi.org/10.1117/12.970948

KEYWORDS: Minerals, Nitrogen, Proteins, Molecules, Comets, Sulfur, Bacteria, X-rays, Carbon, Iron

Read Abstract +

Proceedings Article | 13 November 2012 Paper

Microscopic and microbiological investigations of Mississippian sylvite

Richard Hoover, Elena Pikuta

Proceedings Volume 8521, 852108 (2012) https://doi.org/10.1117/12.971045

KEYWORDS: Crystals, Microorganisms, Bacteria, Minerals, Mining, Crystallography, Microscopy, Microscopes, Microbiology, Comets

Read Abstract +

Proceedings Article | 13 November 2012 Paper

Comets as parent bodies of CI1 carbonaceous meteorites and possible habitats of ice-microbes

N. Chandra Wickramasinghe, Janaki Wickramasinghe, Jamie Wallis, Richard Hoover, Alexei Rozanov

Proceedings Volume 8521, 85210Q (2012) https://doi.org/10.1117/12.975979

KEYWORDS: Comets, Liquids, Minerals, Microorganisms, Molecules, Asteroids, Bacteria, Solar system, Fusion energy, Crystals

Read Abstract +

Proceedings Article | 24 October 2012 Paper

Possible biological structures in the Tissint Mars Meteorite

Jamie Wallis, N. Chandra Wickramasinghe, Daryl Wallis, Nori Miyake, Max Wallis, Barry Di Gregorio, Richard Hoover

Proceedings Volume 8521, 85210R (2012) https://doi.org/10.1117/12.2013827

KEYWORDS: Mars, Iron, Scanning electron microscopy, Pyrite, Minerals, Particles, X-rays, Sensors, Carbon, Silicon

Read Abstract +

Proceedings Article | 15 October 2012 Paper

Microbiological study of the Murchison CM2 meteorite

Elena Pikuta, Richard Hoover

Proceedings Volume 8521, 852105 (2012) https://doi.org/10.1117/12.929815

KEYWORDS: Magnesium, Microorganisms, Contamination, Nitrogen, Minerals, Chemical elements, Scanning electron microscopy, Carbon, Biological research, Iron

Read Abstract +

Proceedings Article | 15 October 2012 Paper

Carbonaceous chondrites as bioengineered comets

Robert Sheldon, Richard Hoover

Proceedings Volume 8521, 85210N (2012) https://doi.org/10.1117/12.930061

KEYWORDS: Magnetism, Comets, Crystals, Solar processes, Bacteria, Spherical lenses, Nanocrystals, Liquids, Scanning electron microscopy, Biology

Read Abstract +

Proceedings Article | 23 September 2011 Paper

Anaerobic cultures from preserved tissues of baby mammoth

Elena Pikuta, Daniel Fisher, Richard Hoover

Proceedings Volume 8152, 81520U (2011) https://doi.org/10.1117/12.897080

KEYWORDS: Bacteria, Yeast, Tissues, Microorganisms, Stomach, Bioalcohols, Contamination, Biological research, Teeth, Bone

Read Abstract +

Proceedings Article | 23 September 2011 Paper

Spectral profiling and imaging (SPI): extending L.I.F.E. technology for the remote exploration of life in ice caves (R.E.L.I.C.) on Earth and Mars

Michael Storrie-Lombardi, Alex Hall, Steven Hang, Gregory Lyzenga, Christopher Clark, Birgit Sattler, Asim Bej, Richard Hoover

Proceedings Volume 8152, 815217 (2011) https://doi.org/10.1117/12.916987

KEYWORDS: Luminescence, Reflectivity, Mars, Microorganisms, Robotics, Raman spectroscopy, Bacteria, Profiling, Imaging systems, Organisms

Read Abstract +

Proceedings Article | 23 September 2011 Paper

Comets as parent bodies of CI1 carbonaceous meteorites and possible habitats of ice-microbes

N. Chandra Wickramasinghe, Janaki Wickramasinghe, Jamie Wallis, Richard Hoover, Alexei Rozanov

Proceedings Volume 8152, 81520Z (2011) https://doi.org/10.1117/12.898586

KEYWORDS: Comets, Minerals, Astrobiology, Current controlled current source, Molecules, Molecular biology, Asteroids, Liquids, Earth's atmosphere, Mode conditioning cables

Read Abstract +

Recent studies of comets and cometary dust have confirmed the presence of biologically relevant organic molecules along with clay minerals and water ice. It is also now well established by deuterium/hydrogen ratios that the CI1 carbonaceous meteorites contain indigenous extraterrestrial water. The evidence of extensive aqueous alteration of the minerals in these meteorites led to the hypothesis that water-bearing asteroids or comets represent the parent bodies of the CI1 (and perhaps CM2) carbonaceous meteorites. These meteorites have also been shown to possess a diverse array of complex organics and chiral and morphological biomarkers. Stable isotope studies by numerous independent investigators have conclusively established that the complex organics found in these meteorites are both indigenous and extraterrestrial in nature. Although the origin of these organics is still unknown, some researchers have suggested that they originated by unknown abiotic mechanisms and may have played a role in the delivery of chiral biomolecules and the origin of life on Early Earth. In this paper we review these results and investigate the thermal history of comets. We show that permanent as well as transient domains of liquid water can be maintained on a comet under a plausible set of assumptions. With each perihelion passage of a comet volatiles are preferentially released, and during millions of such passages the comet could shed crustal debris that may survive transit through the Earth's atmosphere as a carbonaceous meteorite. We review the current state of knowledge of comets and carbonaceous meteorites. We also present the results of recent studies on the long-term viability of terrestrial ice-microbiota encased in ancient glacial ice and permafrost. We suggest that the conditions which have been observed to prevail on many comets do not preclude either survivability (or even the active metabolism and growth) of many types of eukaryotic and prokaryotic microbial extremophiles-including algae, cyanobacteria, bacteria and archaea. It is argued that the chemical and morphological biomarkers detected on comets and carbonaceous meteorites can be explained by ancient microbial activity without the need to invoke unknown abiotic production mechanisms.

Proceedings Article | 23 September 2011 Paper

More evidence for liquid water on comets

Robert Sheldon, Richard Hoover

Proceedings Volume 8152, 81520D (2011) https://doi.org/10.1117/12.896851

KEYWORDS: Comets, Liquids, Asteroids, Sun, Sodium, Calcium, Chlorine, Mars, Monochromatic aberrations, Magnesium

Read Abstract +

Proceedings Article | 23 September 2011 Paper

Multicellular algae from lower Proterozoic (2.45 Ga) weathering crusts of the Kola Peninsula

Marina Astafieva, Alexei Rozanov, Richard Hoover

Proceedings Volume 8152, 815205 (2011) https://doi.org/10.1117/12.892453

KEYWORDS: Gallium, Databases, Contamination, Bacteria, Chemical analysis, Bridges, Potassium, Calcium, Iron, Basic research

Read Abstract +

Proceedings Article | 21 September 2011 Paper

Filaments in carbonaceous meteorites: mineral crystals, modern bio-contaminants or indigenous microfossils of trichomic prokaryotes?

Richard Hoover, Alexei Rozanov

Proceedings Volume 8152, 815204 (2011) https://doi.org/10.1117/12.898659

KEYWORDS: Minerals, Nitrogen, Magnesium, Crystals, X-rays, Scanning electron microscopy, Iron, Silicon, Bacteria, Sensors

Read Abstract +

Proceedings Article | 7 September 2010 Paper

Comparison of the microbial diversity and abundance between the freshwater land-locked lakes of Schirmacher Oasis, and the perennially ice-covered Lake Untersee in East Antarctica

Jonathan Huang, Richard Hoover, Ashit Swain, Chris Murdock, Dale Andersen, Asim Bej

Proceedings Volume 7819, 78190W (2010) https://doi.org/10.1117/12.863131

KEYWORDS: Microorganisms, Water, Bacteria, Ecosystems, Astrobiology, Solar radiation, In situ metrology, Ultraviolet radiation, Plating, Analytical research

Read Abstract +

Proceedings Article | 7 September 2010 Paper

Utilization of alternate chirality enantiomers in microbial communities

Elena Pikuta, Richard Hoover

Proceedings Volume 7819, 78190P (2010) https://doi.org/10.1117/12.862232

KEYWORDS: Control systems, Microorganisms, Organisms, Genetics, Bacteria, Molecules, Astrobiology, Mode conditioning cables, Biological research, Proteins

Read Abstract +

Proceedings Article | 7 September 2010 Paper

Chiral biomarkers and microfossils in carbonaceous meteorites

Richard Hoover

Proceedings Volume 7819, 781903 (2010) https://doi.org/10.1117/12.863372

KEYWORDS: Nitrogen, Proteins, Organisms, Molecules, Biology, Chemical species, Bacteria, Crystals, Carbon, X-rays

Read Abstract +

Proceedings Article | 7 September 2010 Paper

Comparative methods of investigating microfossils in ancient Archaean to Lower Proterozoic (AR-PR1) rocks

Marina Astafieva, Alexei Yu. Rozanov, Richard Hoover

Proceedings Volume 7819, 781907 (2010) https://doi.org/10.1117/12.861622

KEYWORDS: Scanning electron microscopy, Crystals, Microscopes, Contamination, Chemical analysis, Electron microscopes, Spherical lenses, Aerospace engineering, Optical microscopy, Microorganisms

Read Abstract +

Proceedings Article | 7 September 2010 Paper

Early Precambrian pillow lavas as habitat for microfossils

Marina Astafieva, Alexei Yu. Rozanov, Maria Bogina, Alexei Chistyakov, Eugene Sharkov, Richard Hoover

Proceedings Volume 7819, 781908 (2010) https://doi.org/10.1117/12.859835

KEYWORDS: Microorganisms, Bacteria, Gallium, Interfaces, Aerospace engineering, Organisms, Crystals, Geology, Mineralogy, Astrobiology

Read Abstract +

Proceedings Article | 7 September 2010 Paper

Development of an autofluorescence spectral database for the identification and classification of microbial extremophiles

Justin Davis, Hillari Howard, Richard Hoover, Chandran Sabanayagam

Proceedings Volume 7819, 78190O (2010) https://doi.org/10.1117/12.863994

KEYWORDS: Luminescence, Microscopes, Microorganisms, Organisms, Databases, Chromophores, Objectives, Solar system, Absorption, Optical filters

Read Abstract +

Proceedings Article | 11 September 2009 Paper

Diversity of bacterial communities in the lakes of Schirmacher Oasis, Antarctica

Nazia Mojib, Jonathan Huang, Richard Hoover, Elena Pikuta, Michael Storrie-Lombardi, Birgit Sattler, Dale Andersen, Asim Bej

Proceedings Volume 7441, 74410J (2009) https://doi.org/10.1117/12.831289

KEYWORDS: Bacteria, Microorganisms, Water, Ecosystems, Liquids, Aerospace engineering, Geology, Biological research, Taxonomy, Astrobiology

Read Abstract +

Proceedings Article | 11 September 2009 Paper

Life in ice: implications to astrobiology

Richard Hoover, Elena Pikuta

Proceedings Volume 7441, 74410P (2009) https://doi.org/10.1117/12.832640

KEYWORDS: Bacteria, Microorganisms, Liquids, Astrobiology, Molecules, Water, Mars, Proteins, Mode conditioning cables, Solar system

Read Abstract +

Proceedings Article | 11 September 2009 Paper

Fossil microorganisms and formation of Early Precambrian weathering crusts

M. Astafieva, A. Yu. Rozanov, A. Vrevsky, N. Alfimova, V. Matrenichev, R. Hoover

Proceedings Volume 7441, 744107 (2009) https://doi.org/10.1117/12.824535

KEYWORDS: Microorganisms, Minerals, Chemical elements, Bacteria, Quartz, Iron, Climatology, Silicon, Aluminum, Titanium dioxide

Read Abstract +

Proceedings Article | 11 September 2009 Paper

On the search for the amino acids on the lunar surface as it relates to other extraterrestrial bodies

Vera Kolb, Richard Hoover, Stephen Macko

Proceedings Volume 7441, 744106 (2009) https://doi.org/10.1117/12.831232

KEYWORDS: Proteins, Statistical analysis, Contamination, Chromatography, Mars, Rockets, Aerospace engineering, Soil contamination, Spectroscopy, Liquids

Read Abstract +

Proceedings Article | 11 September 2009 Paper

Volcanic glasses as habitat for microfossils: evidence from the early Paleoproterozoic pillow lavas of Karelia and their modern analogues in the Mid-Atlantic Ridge

M. Astafieva, A. Rozanov, E. Sharkov, A. Chistyakov, M. Bogina, R. Hoover

Proceedings Volume 7441, 744104 (2009) https://doi.org/10.1117/12.828469

KEYWORDS: Glasses, Microorganisms, Bacteria, Gallium, Organisms, Silica, Iron, Electron microscopes, Structural health monitoring, Magnesium

Read Abstract +

Proceedings Article | 4 September 2009 Paper

Microfossils in carbonaceous meteorites

Richard Hoover

Proceedings Volume 7441, 744103 (2009) https://doi.org/10.1117/12.832643

KEYWORDS: Nitrogen, Minerals, Bacteria, Proteins, Magnesium, Sulfur, Oxygen, Astrobiology, Silicon, Scanning electron microscopy

Read Abstract +

Proceedings Article | 4 September 2009 Paper

Psychrotolerant anaerobes from Lake Podprudnoye, Antarctica and penguin Spheniscus demersus colony, South Africa

Melissa Guisler, Elena Pikuta, Alisa Townsend, Richard Hoover

Proceedings Volume 7441, 74410L (2009) https://doi.org/10.1117/12.828880

KEYWORDS: Bacteria, Yeast, Organisms, Microorganisms, Proteins, Ecosystems, Liquids, Astrobiology, Temperature metrology, Urea

Read Abstract +

The study of a sample collected from a wind-made ice sculpture near Lake Podprudnoe, Antarctica led to the isolation of the psychrotolerant strain ISLP-3. Cells of the new isolate are vibrio-shaped that measure 0.5 x 1.0-3.0 μm in size. Growth occurs within the temperature range 5-35ºC with the optimum at 22 °C. Salinity range for growth is 0-2 % NaCl with the optimum at 0.25 %. The new isolate grows within a pH range from 6.0 to 9.5 with the optimum at 7.5. Strain ISLP-3 is saccharolytic, growing on the following substrates: D-glucose, D-ribose, D-fructose, D-arabinose, maltose, sucrose, D-trehalose, D-mannose, D-cellobiose, lactose, starch, chitin, triethylamine, N-acetylglucosamine, and urea. The best growth occurred on D-cellobiose. An environmental sample of pond water near a colony of the endemic species of African penguins, Spheniscus demersus, was collected in February 2008 and delivered directly to the Astrobiology laboratory at NSSTC. The microbiological study of this sample led to the isolation of two psychrotolerant strains ARHSd-7G and ARHSd-9G. Both strains are strictly anaerobic bacteria and are able to grow at high pH and low temperatures. The cells of strain ARHSd-7G are motile, vibrio-shaped, spore-forming cells. Optimal growth of this strain occurs at 30 ºC, 3 % NaCl, and pH 8.9. The isolate ARHSd-7G combines sugarlytic and proteolytic metabolisms, growing on some proteolysis products including peptone and yeast extract and a number of sugars. The second isolate, ARHSd-9G, exhibits thin, elongated rods that measure 0.4 x 3-5 μm. The cells are motile and spore-forming. Optimal growth of strain ARHSd-9G occurs at 30 ºC, 1.75 % NaCl, and pH 8.5. The strain ARHSd-9G is sugarlytic, growing well on substrates such as D-glucose, sucrose, D-cellobiose, maltose, fructose, D-mannose, and trehalose (the only exception is positive growth on yeast extract). In this report, the physiological and morphological characteristics of the novel psychrotolerant, alkaliphilic, and neutrophilic isolates from the Antarctica 2008 expedition will be discussed.

Proceedings Article | 4 September 2009 Paper

A micro fluorescent activated cell sorter for astrobiology applications

Donald Platt, Richard Hoover

Proceedings Volume 7441, 74410B (2009) https://doi.org/10.1117/12.831336

KEYWORDS: Bacteria, Microfluidics, Astrobiology, Microorganisms, Electronics, Solar system, Space operations, Photodetectors, Microcontrollers, System integration

Read Abstract +

Proceedings Article | 4 September 2009 Paper

Anaerobic psychrophiles from Lake Zub and Lake Untersee, Antarctica

Alisa Townsend, Elena Pikuta, Melissa Guisler, Sarah Stahl, Richard Hoover

Proceedings Volume 7441, 74410K (2009) https://doi.org/10.1117/12.828877

KEYWORDS: Ecosystems, Microorganisms, Bacteria, Yeast, Temperature metrology, Physiology, Oxygen, Ions, Astrobiology, Sodium

Read Abstract +

The study of samples from Antarctica 2008 and 2009 expeditions organized and successfully conducted by Richard Hoover led to the isolation of diverse anaerobic strains with psychrotolerant and psychrophilic physiology. Due to the fact that Lake Untersee has never been subject to microbiological study, this work with the samples has significant and pioneering impact to the knowledge about the biology of this unique ecosystem. Also, the astrobiological significance for the study of these ecosystems is based on new findings of ice covered water systems on other bodies of our solar system. Anaerobic psychrotolerant strain LZ-22 was isolated from a frozen sample of green moss with soils around the rhizosphere collected near Lake Zub in Antarctica. Morphology of strain LZ-22 was observed to be motile, rod shaped and spore-forming cells with sizes 1 x 5-10 μm. This new isolate is a mesophile with the maximum temperature of growth at 40°C. Strain LZ-22 is able to live on media without NaCl and in media with up to 7 % (w/v) NaCl. It is catalase negative and grows only on sugars with the best growth rate being on lactose. The strain is a neutrophile and grows between pH 5 and 9.0 with the optimum at 7.8. Another two strains UL7-96mG and LU-96m7P were isolated from deep water samples of Lake Untersee. Proteolytic strain LU-96m7P had a truly psychrophilic nature and refused to grow at room temperature. Sugarlytic strain UL7-96mG was found to be psychrotolerant, but its rate of growth at 3°C was very high compared with other mesophiles. Two homoacetogenic psychrophilic strains A7AC-96m and AC-DS7 were isolated and purified from samples of Lake Untersee; both of them are able to grow chemolithotrophically on H₂+CO₂. In the presence of lactate, these strains are able to grow only at 0-18 °C, and growth at 22 °C was observed only with yeast extract stimulation. In this paper, physiological and morphological characteristics of novel psychrophilic and psychrotolerant isolates from Antarctica 2008 and 2009 expeditions will be discussed.

Proceedings Article | 2 September 2008 Paper

Diversity and cold adaptation of microorganisms isolated from the Schirmacher Oasis, Antarctica

Nazia Mojib, Asim Bej, Richard Hoover

Proceedings Volume 7097, 70970K (2008) https://doi.org/10.1117/12.795394

KEYWORDS: Microorganisms, Proteins, Statistical analysis, Tolerancing, Biological research, Solar radiation, Ultraviolet radiation, Biology, Aerospace engineering, Oceanography

Read Abstract +

Proceedings Article | 2 September 2008 Paper

Development of living organisms on the lava-water interface of Palaeoproterozoic Ongeluk lavas of South Africa

M. Astafieva, A. Rozanov, D. Cornell, R. Hoover

Proceedings Volume 7097, 709704 (2008) https://doi.org/10.1117/12.791901

KEYWORDS: Bacteria, Organisms, Microorganisms, Interfaces, Spherical lenses, Metals, Aerospace engineering, Gallium, Scanning electron microscopy, Electron microscopes

Read Abstract +

Proceedings Article | 2 September 2008 Paper

Microfossils of filamentous prokaryotes in CI1 and CM2 meteorites

Richard Hoover

Proceedings Volume 7097, 709703 (2008) https://doi.org/10.1117/12.801013

KEYWORDS: Nitrogen, Bacteria, Sulfur, X-rays, Carbon, Microorganisms, Minerals, Biological research, Organisms, Contamination

Read Abstract +

Proceedings Article | 2 September 2008 Paper

Microbial extremophiles from the 2008 Schirmacher Oasis Expedition: preliminary results

Richard Hoover, Elena Pikuta, Alisa Townsend, Joshua Anthony, Melissa Guisler, Jasmine McDaniel, Asim Bej, Michael Storrie-Lombardi

Proceedings Volume 7097, 70970L (2008) https://doi.org/10.1117/12.801018

KEYWORDS: Bacteria, Astrobiology, Reconnaissance, Liquids, Minerals, Microorganisms, Yeast, Methane, Aerospace engineering, Mars

Read Abstract +

Among the most interesting targets for Astrobiology research are the polar ice caps and the permafrost of Mars and the ice and liquid water bodies that may lie beneath the frozen crusts of comets, the icy moons of Jupiter (Europa, Io and Ganymede) and Saturn (Titan and Enceladus). The permanently ice-covered lakes of Antarctica, such as Lake Vostok and Lake Untersee, provide some of the best terrestrial analogues for these targets. The 2008 International Tawani Schirmacher Oasis/Lake Untersee Expeditions have been organized to conduct studies of novel microbial extremophiles and investigate the biodiversity of the glaciers and ice-covered lakes of Dronning Maud Land, East Antarctica. This paper describes the preliminary analysis of the anaerobic microbial extremophiles isolated from samples collected during the 2008 International Schirmacher Oasis Antarctica Reconnaissance Expedition. These samples showed great diversity of psychrophlic and psychrotolerant bacteria. Six new anaerobic strains have been isolated in pure cultures and partially characterized. Two of them (strains ARHSd-7G and ARHSd-9G) were isolated from a small tidal pool near the colony of African Penguins Spheniscus demersus. Strain ARHSd-7G was isolated on mineral anaerobic medium with 3 % NaCl, pH 7 and D-glucose, it has motile, vibrion shape cells, and is Gram variable. Strain ARHSd-9G grew on anaerobic, alkaline medium with pH 9 and 1 % NaCl at 3°C. The substrate was D-glucose supplemented with yeast extract (0.05 %). Cells of strain ARHSd-9G had morphology of straight or slightly curved elongated rods and demonstrated unusual optical effects under dark-field visible light microscopy. The cells were spore-forming and Gram positive. From the mat sample collected near Lake Zub, the new strain LZ-3 was isolated in pure culture at 3°C. Strain LZ-3 was anaerobic and grew on 0.5 % NaCl mineral medium with Dglucose as a substrate. The gram positive cells were spore-forming. They exhibited a distinctive morphology of large rods with rounded ends and size 1x10 μm. From the sample of ice sculpted by wind and melting by solar heating, containing many entrained black rocks collected near Lake Podprudnoye the new strain ISLP-22 was isolated in pure culture. The cells of this strain had vibrion shape and were spore-forming and had "baseball bat" shapes). This culture preferred 0.1 % NaCl mineral anaerobic medium and grew rapidly at 3 °C. Currently, all strains are under physiological study and phylogenetic analysis.

Proceedings Article | 28 August 2008 Paper

Cosmological evolution: spatial relativity and the speed of life

Robert Sheldon, Richard Hoover

Proceedings Volume 7097, 709716 (2008) https://doi.org/10.1117/12.802195

KEYWORDS: Comets, Chemical species, Physics, Organisms, Galactic astronomy, Biology, Ecology, Bacteria, Eye, Relativity

Read Abstract +

Proceedings Article | 28 August 2008 Paper

What do membrane lipids tell us about the microorganisms living in extreme environments?

Susan Pfiffner, Sarah DiFurio, Ying-Dong Gan, Richard Hoover

Proceedings Volume 7097, 70970M (2008) https://doi.org/10.1117/12.795378

KEYWORDS: Biological research, Mining, Bacteria, Statistical analysis, Microorganisms, Carbon, Ions, Astrobiology, Molecules, Chemical analysis

Read Abstract +

Proceedings Article | 28 August 2008 Paper

Epifluorescence surveys of extreme environments using PanCam imaging systems: Antarctica and the Mars regolith

Michael Storrie-Lombardi, Jan-Peter Muller, Martin Fisk, Andrew Griffiths, Andrew Coates, Richard Hoover

Proceedings Volume 7097, 70970P (2008) https://doi.org/10.1117/12.800924

KEYWORDS: Mars, Luminescence, Ultraviolet radiation, Cameras, Imaging systems, Light emitting diodes, Optical filters, Analog electronics, Robotics, Semiconductor lasers

Read Abstract +

Proceedings Article | 28 August 2008 Paper

The early Earth and its environments

A. Yu. Rozanov, M. Astafieva, R. Hoover

Proceedings Volume 7097, 709708 (2008) https://doi.org/10.1117/12.791902

KEYWORDS: Bacteria, Microorganisms, Minerals, Organisms, Gallium, Natural surfaces, Oxygen, Spherical lenses, Earth's atmosphere, Aerospace engineering

Read Abstract +

Proceedings Article | 9 October 2007 Paper

Early Proterozoic (2.04 GA) phosphorites of Pechenga Greenstone Belt and their origin

Alexei Yu. Rozanov, Marina Astafieva, Richard Hoover

Proceedings Volume 6694, 669409 (2007) https://doi.org/10.1117/12.726440

KEYWORDS: Bacteria, Sulfur, Gallium, Microorganisms, Oceanography, Scanning electron microscopy, Electron microscopes, Oxygen, Minerals, Oxidation

Read Abstract +

Proceedings Article | 3 October 2007 Paper

Microfossils of cyanobacteria in carbonaceous meteorites

Richard Hoover

Proceedings Volume 6694, 669408 (2007) https://doi.org/10.1117/12.742284

KEYWORDS: Bacteria, Iron, Minerals, Carbon, Silicon, Surface conduction electron emitter displays, Scanning electron microscopy, Liquids, Electron microscopes, X-rays

Read Abstract +

During the past decade, Environmental and Field Emission Scanning Electron Microscopes have been used at the NASA/Marshall Space Flight Center to investigate freshly fractured interior surfaces of a large number of different types of meteorites. Large, complex, microfossils with clearly recognizable biological affinities have been found embedded in several carbonaceous meteorites. Similar forms were notably absent in all stony and nickel-iron meteorites investigated. The forms encountered are consistent in size and morphology with morphotypes of known genera of Cyanobacteria and microorganisms that are typically encountered in associated benthic prokaryotic mats. Even though many coccoidal and isodiametric filamentous cyanobacteria have a strong morphological convergence with some other spherical and filamentous bacteria and algae, many genera of heteropolar cyanobacteria have distinctive apical and basal regions and cellular differentiation that makes it possible to unambiguously recognize the forms based entirely upon cellular dimensions, filament size and distinctive morphological characteristics. For almost two centuries, these morphological characteristics have historically provided the basis for the systematics and taxonomy of cyanobacteria. This paper presents ESEM and FESEM images of embedded filaments and thick mats found in-situ in the Murchison CM2 and Orgueil CI1 carbonaceous meteorites. Comparative images are also provided for known genera and species of cyanobacteria and other microbial extremophiles. Energy Dispersive X-ray Spectroscopy (EDS) indicates that the meteorite filaments typically exhibit dramatic chemical differentiation with distinctive difference between the possible microfossil and the meteorite matrix in the immediate proximity. Chemical differentiation is also observed within these microstructures with many of the permineralized filaments enveloped within electron transparent carbonaceous sheaths. Elemental distributions of these embedded filaments are not consistent with recent cyanobacteria or other living or preserved microbial extremophiles that have been investigated during this research. The meteorite filaments often have a nitrogen content below the sensitivity level of the EDS detector. Carbon, Sulfur, Iron or Silicon is often highly enriched and hence anomalous C/N and C/S ratios when compared with modern cyanobacteria. The meteorite forms that are unambiguously recognizable as biological filaments are interpreted as indigenous microfossils analogous to several known genera of modern cyanobacteria and associated trichomic filamentous prokaryotes.

Proceedings Article | 3 October 2007 Paper

Ratios of biogenic elements for distinguishing recent from fossil microorganisms

Richard Hoover

Proceedings Volume 6694, 66940D (2007) https://doi.org/10.1117/12.742285

KEYWORDS: Nitrogen, Carbon, Organisms, Sulfur, Magnesium, Oxygen, X-rays, Bacteria, Microorganisms, Chemical elements

Read Abstract +

Proceedings Article | 1 October 2007 Paper

The cometary biosphere

Robert Sheldon, Richard Hoover

Proceedings Volume 6694, 66940H (2007) https://doi.org/10.1117/12.729094

KEYWORDS: Comets, Solar system, Galactic astronomy, Stars, Sun, Clouds, Nitrogen, Organisms, Bacteria, Ecosystems

Read Abstract +

Proceedings Article | 1 October 2007 Paper

Could there have been a single origin of life in a big bang universe?

Richard Gordon, Richard Hoover

Proceedings Volume 6694, 669404 (2007) https://doi.org/10.1117/12.737041

KEYWORDS: Planets, Stars, Galactic astronomy, Planetary systems, Solar system, Metals, Particles, Organisms, Astrobiology, Microorganisms

Read Abstract +

Proceedings Article | 1 October 2007 Paper

Diatoms in space: testing prospects for reliable diatom nanotechnology in microgravity

Richard Gordon, Richard Hoover, Jack Tuszynski, Javier de Luis, Philip Camp, Mary Ann Tiffany, Stephen Nagy, Mostafa Fayek, Pascal Lopez, Beatriz Lerner

Proceedings Volume 6694, 66940V (2007) https://doi.org/10.1117/12.737051

KEYWORDS: Nanotechnology, Silica, Oceanography, Silicon, Control systems, Biology, Electronics, Microfluidics, Space operations, Cytoskeletons

Read Abstract +

Proceedings Article | 1 October 2007 Paper

Microbial extremophiles in evolutionary aspect

Elena Pikuta, Richard Hoover

Proceedings Volume 6694, 66941C (2007) https://doi.org/10.1117/12.742289

KEYWORDS: Microorganisms, Astrobiology, Planets, Ecosystems, Mars, Organisms, Bacteria, Liquids, Minerals, Carbonates

Read Abstract +

Proceedings Article | 14 September 2006 Paper

Probabilistic classification of elemental abundance distributions in Nakhla and Apollo 17 lunar dust samples

Michael Storrie-Lombardi, Richard Hoover, Mian Abbas, G. Jerman, J. Coston, Martin Fisk

Proceedings Volume 6309, 630906 (2006) https://doi.org/10.1117/12.690435

KEYWORDS: Principal component analysis, Mars, Carbon, Statistical analysis, Stochastic processes, Scanning electron microscopy, Artificial neural networks, Chlorine, Sodium, Aluminum

Read Abstract +

Analysis of spectral and imaging data from meteoritic samples and sample return missions would benefit significantly from a systematic, quantitative statistical classification methodology and a common set of standards for data collection [McDonald and Storrie-Lombardi, 2006]. Stochastic artificial neural networks can be trained using elemental abundance distributions for the detection of macroscopic fossils [Storrie-Lombardi and Hoover, 2004] and extant microbial life [Storrie-Lombardi and Hoover, 2005]. These non-linear algorithms are particularly attractive since they can produce a Bayesian estimate of the classification accuracy of either human experts or automated, unsupervised classification algorithms. In sub-ocean and surface basalts on earth the networks can distinguish regions of biotic and abiotic alteration of basalt glass from unaltered samples using only elemental abundances as inputs [Storrie-Lombardi and Fisk, 2004b]. Recently, evidence has been presented documenting the presence of morphologic signatures in the Mars meteorite Nakhla [Fisk et al., 2004; Fisk et al., 2006] previously noted in regions of biotic alteration in sub-ocean and surface terrestrial basalts [Fisk et al., 2003; Furnes et al., 2004]. The tunneling alterations are not conclusive evidence of biotic alteration of Nakhla on Mars. However, the meteorite is well known to have experienced aqueous alteration prior to arrival on earth and is rich in carbon [Gibson et al., 2006; McKay et al., 2006]. We here present an initial application of our probabilistic classification strategy to assess elemental abundance distributions from multiple target regions in Nakhla and lunar dust samples collected by Apollo 17 astronauts. We present scanning electron microscope images and elemental abundance point distributions (C, N, O, Na2O, MgO, Al2O3, SiO2, P2O5, S, Cl, K2O, CaO, and FeO) for a series of target regions. We discuss our observations in the context of data previously presented in these meetings for extant cyanobacteria, fossil trilobites, Orgueil meteorite, and terrestrial basalt targets. These data are being added to a database that will made available to the biogeology and astrobiology communities as part of an ongoing effort to provide a quantitative probabilistic methodology for analysis of putative elemental abundance geobiological signatures.

Proceedings Article | 14 September 2006 Paper

Implications of cometary water: deep impact, stardust, and Hyabusa

Robert Sheldon, Richard Hoover

Proceedings Volume 6309, 63090L (2006) https://doi.org/10.1117/12.681232

KEYWORDS: Comets, Liquids, Asteroids, Clouds, Particles, Silicates, Mars, Spherical lenses, Data modeling, Jupiter

Read Abstract +

Proceedings Article | 14 September 2006 Paper

Bacterial utilization of L-sugars and D-amino acids

Elena Pikuta, Richard Hoover, Brig Klyce, Paul Davies, Pauline Davies

Proceedings Volume 6309, 63090A (2006) https://doi.org/10.1117/12.690434

KEYWORDS: Molecules, Microorganisms, Proteins, Bacteria, Organisms, Comets, Tissues, Carbon, Crystals, Polymers

Read Abstract +

The fact that organotrophic organisms on Earth use L-amino acids and D-sugars as an energy source is recognized as one of the universal features of life. The chirality of organic molecules with asymmetric location of group-radicals was described a relatively long time ago. Louis Pasteur observed that abiotic (chemical) processes produced mixtures with equal numbers (racemic) of the two forms but that living organisms possessed a molecular asymmetry that included only one of the enantiomers (homochirality). He speculated that the origin of the asymmetry of chiral biomolecules might hold the key to the nature of life. All of the amino acids in proteins (except for Glycine which is symmetrical) exhibit the same absolute steric configuration as L-glyceraldehyde. D-amino acids are never found in proteins, although they do exist in nature and are often found in polypeptide antibiotics. Constitutional sugars of cells, opposite to the amino acids, are the D-enantiomers, and the appearance of L-sugars in Nature is extremely rare. Notwithstanding this fact, the metabolism of some bacteria does have the capability to use amino acids and sugars with alternative chirality. This property may be caused by the function of specific enzymes belonging to the class of isomerases (racemases, epimerases, isomerases, tautomerases). In our laboratory, we have investigated several anaerobic bacterial strains, and have found that some of these bacteria are capable of using D-amino acids and L-sugars. Strain BK1 is capable of growth on D-arginine, but its growth characteristics on L-arginine are approximately twice as high. Another alkaliphilic strain SCA^T (= ATCC BAA-1084^T = JCM 12857^T = DSM 17722^T = CIP 107910^T) was found to be capable of growth on L-ribose and L-arabinose. It is interesting that this strain was incapable of growth on D-arabinose, which suggests the involvement of some alternative mechanism of enzyme activity. In this paper, we describe the preliminary results of these microbiological studies and discuss some possible implications.

Proceedings Article | 14 September 2006 Paper

Fossil microorganisms in the Archaean

Marina Astafieva, Richard Hoover, Alexei Yu. Rozanov, Alexander Vrevskiy

Proceedings Volume 6309, 630904 (2006) https://doi.org/10.1117/12.681660

KEYWORDS: Microorganisms, Contamination, Bacteria, Electron microscopes, Fungi, Aerospace engineering, Scanning electron microscopy, Silica, Spherical lenses, Optical spheres

Read Abstract +

Proceedings Article | 14 September 2006 Paper

Thiophenes as indicators of aqueous alteration in carbonaceous meteorites

Mark Sephton, Randall Perry, Richard Hoover

Proceedings Volume 6309, 63090Q (2006) https://doi.org/10.1117/12.698393

KEYWORDS: Sulfur, Solar system, Ions, Toxic industrial chemicals, Macromolecules, Liquids, Asteroids, Organic materials, Nitrogen, Curium

Read Abstract +

Proceedings Article | 14 September 2006 Paper

Fossils of Prokaryotic microorganisms in the Orgueil meteorite

Richard Hoover

Proceedings Volume 6309, 630902 (2006) https://doi.org/10.1117/12.690441

KEYWORDS: Minerals, Magnesium, Iron, Crystals, Microorganisms, Carbon, Nitrogen, Liquids, Silicon, Chemical analysis

Read Abstract +

The Orgueil CI1 meteorite, which fell in southern France on the evening of May 14, 1864, has been one of the most extensively studied of all known carbonaceous meteorites. Environmental and Field Emission Scanning Electron Microscopy (ESEM and FESEM) studies of freshly fractured interior surfaces of the Orgueil meteorite have resulted in the detection of the fossilized remains of a large and diverse population of filamentous prokaryotic microorganisms. The taphonomy and the modes of the preservation of these remains are diverse. Some of the remains exhibit carbonization of a hollow sheath and in other cases the remains are permineralized with watersoluble evaporite minerals, such as magnesium sulfate or ammonium salts. Images and EDS spectral data are provided documenting a variety of Orgueil microstructures: abiotic evaporite minerals; pre-solar grains; framboids, ovoids and fluorine-rich filaments of indeterminate biogenicity. These results provide information regarding the size, size range, morphologies and chemical compositions of abiotic microstructures found in native cryptohalite and crystalline and fibrous epsomites from Poison Lake, Washington, USA and Catalayud, Zaragoza, Aragon, Spain. High resolution ESEM and FESEM secondary and backscattered electron Images and Energy Dispersive X-ray Spectroscopy (EDS) data will also be presented of recognizable filamentous cyanobacteria and other prokaryotic microfossils. Many of the microfossils found embedded in the meteorite rock matrix are consistent in size and microstructure with known genera and species of filamentous cyanobacteria. Many of these forms can be recognized as morphotypes of cyanobacteria belonging to the Order Oscillatoriaceae. These large, complex microstructures are clearly distinguishable from the abiotic minerals examined - cryptohalite and fibrous epsomites. Many of the well-preserved filamentous forms in the Orgueil meteorite are embedded in the rock matrix and exhibit identifiable biological characteristics and EDS elemental compositions that clearly differentiate them from abiotic microstructures. They exhibit branched and unbranched filaments; uniseriate and multiseriate ensheathed trichomes with specialized cells and structures for reproduction (e.g. hormogonia and akinetes) and nitrogen fixation (heterocysts). The meteorite forms also show evidence of motility (emergent hormogonia and hollow, coiled empty sheaths) and they are often found in mats, consortia and microbial assemblages that are consistent with the known associations and ecologies of modern genera and species of cyanobacteria. Smaller filaments, consistent with the phototrophic filamentous prokaryotes typically present in anoxic layers associated with modern cyanobacterial mats, have also been found in the Orgueil meteorite.

Proceedings Article | 14 September 2006 Paper

Comets, asteroids, meteorites, and the origin of the Biosphere

Richard Hoover

Proceedings Volume 6309, 63090J (2006) https://doi.org/10.1117/12.690437

KEYWORDS: Comets, Asteroids, Liquids, Temperature metrology, Bacteria, Curium, Sun, Earth's atmosphere, Space operations, Solar system

Read Abstract +

During the past few decades, the delivery of water, organics, and prebiotic chemicals to the Biosphere of Earth during the Hadean (4.5-3.8 Ga) period of heavy bombardment by comets and asteroids has become more widely accepted. Comets are still largely regarded as frigid, pristine bodies of protosolar nebula material that are devoid of liquid water and therefore unsuitable for life. Complex organic compounds have been observed in comets and on the water-rich asteroid 1998 KY26 and near IR observations have indicated the presence of crystalline water ice and ammonia hydrate on the large Kuiper Belt object (50000) Quaoar that has resurfacing suggesting cryovolcanic outgassing. Spacecraft observations of the chemical compositions and characteristics of the nuclei of several comets (Halley, Borrelly, Wild 2, and Tempel 1) have shown that comets contain complex organic chemicals; that water is the predominant volatile; and that extremely high temperatures (~350-400 K) can be reached on the surface of the very black (albedo~0.03) nuclei of comets when they approach the Sun. Impact craters and pinnacles observed on comet Wild 2 suggest a thick crust. Episodic outbursts and jets from the nuclei of several comets indicate that localized regimes of liquid water and water vapor can periodically exist beneath the comet crust. The Deep Impact mission found the temperature of the nucleus of comet Tempel 1 at 1.5 AU varied from a minimum of 280 ±8 K the 330K (57 °C) on the sunlit side. In this paper it is argued that that pools and films of liquid water exist (within a wide range of temperatures) in cavities and voids just beneath the hot, black crust. The possibility of liquid water existing over a wide range of temperatures significantly enhances the possibility that comets might contain niches suitable for the growth of microbial communities and ecosystems. These regimes would be ideal for the growth of psychrophilic, mesophilic, and thermophilic photoautotrophs and chemolithotrophs such as the motile filamentous cyanobacteria (e.g., Calothrix, Oscillatoria, Phormidium, and Spirulina) that grow in geothermal springs and geysers of Earth at temperatures ranging from 320K to 345K and are also found growing in cold polar desert soils. The mineralized remains of morphotypes of all of these cyanobacteria have also been found in the Orgueil CI1 and the Murchison CN2 carbonaceous meteorites that may derive from cometary parent bodies. Observational results that support the hypothesis that liquid water can in active regions just beneath the surface of comets and that comets, carbonaceous meteorites, and asteroids may have played a significant role in the origin and evolution of the Biosphere and in the distribution of microbial life throughout the Solar System.s

Proceedings Article | 22 September 2005 Paper

Mineralized remains of morphotypes of filamentous cyanobacteria in carbonaceous meteorites

Richard Hoover

Proceedings Volume 5906, 59060J (2005) https://doi.org/10.1117/12.624419

KEYWORDS: Microorganisms, Minerals, Bacteria, Nitrogen, Contamination, Scanning electron microscopy, Liquids, Spherical lenses, Polymers, Chemical elements

Read Abstract +

The quest for conclusive evidence of microfossils in meteorites has been elusive. Abiotic microstructures, mineral grains, and even coating artifacts may mimic unicellular bacteria, archaea and nanobacteria with simple spherical or rod morphologies (i.e., cocci, diplococci, bacilli, etc.). This is not the case for the larger and more complex microorganisms, colonies and microbial consortia and ecosystems. Microfossils of algae, cyanobacteria, and cyanobacterial and microbial mats have been recognized and described from many of the most ancient rocks on Earth. The filamentous cyanobacteria and sulphur-bacteria have very distinctive size ranges, complex and recognizable morphologies and visibly differentiated cellular microstructures. The taphonomic modes of fossilization and the life habits and processes of these microorganisms often result in distinctive chemical biosignatures associated with carbonization, silicification, calcification, phosphatization and metal-binding properties of their cell-walls, trichomes, sheaths and extracellular polymeric substances (EPS). Valid biogenicity is provided by the combination of a suite of known biogenic elements (that differ from the meteorite matrix) found in direct association with recognizable and distinct biological features and microstructures (e.g., uniseriate or multiseriate filaments, trichomes, sheaths and cells of proper size/size range); specialized cells (e.g., basal or apical cells, hormogonia, akinetes, and heterocysts); and evidence of growth characteristics (e.g., spiral filaments, robust or thin sheaths, laminated sheaths, true or false branching of trichomes, tapered or uniform filaments) and evidence of locomotion (e.g. emergent cells and trichomes, coiling hormogonia, and hollow or flattened and twisted sheaths). Since 1997 we have conducted Environmental and Field Emission Scanning Electron Microscopy (ESEM and FESEM) studies of freshly fractured interior surfaces of carbonaceous meteorites, terrestrial rocks, living, cryopreserved and fossilized extremophiles and cyanobacteria. These studies have resulted in the detection of mineralized remains of morphotypes of filamentous cyanobacteria, mats and consortia in many carbonaceous meteorites. These well-preserved and embedded microfossils are consistent with the size, morphology and ultra-microstructure of filamentous trichomic prokaryotes and degraded remains of microfibrils of cyanobacterial sheaths. EDAX elemental studies reveal that the forms in the meteorites often have highly carbonized sheaths in close association with permineralized filaments, trichomes, and microbial cells. The eextensive protocols and methodologies that have been developed to protect the samples from contamination and to distinguish recent contaminants from indigenous microfossils are described recent bio-contaminants. Ratios of critical bioelements (C:O, C:N, C:P, and C:S) reveal dramatic differences between microfossils in Earth rocks and meteorites and in the cells, filaments, trichomes, and hormogonia of recently living cyanobacteria. The results of comparative optical, ESEM and FESEM studies and EDAX elemental analyses of recent cyanobacteria (e.g. Calothrix, Oscillatoria, and Lyngbya) of similar size, morphology and microstructure to microfossils found embedded in the Murchison CM2 and the Orgueil CI1 carbonaceous meteorites are presented

Proceedings Article | 22 September 2005 Paper

Microbiological methodology in astrobiology

S. Abyzov, L. Gerasimenko, R. Hoover, I. Mitskevich, A. Mulyukin, M. Poglazova, A. Rozanov

Proceedings Volume 5906, 59060A (2005) https://doi.org/10.1117/12.618565

KEYWORDS: Microorganisms, Biological research, Statistical analysis, Bacteria, Electron microscopy, Plating, Yeast, Astrobiology, Contamination, Planets

Read Abstract +

Proceedings Article | 22 September 2005 Paper

Morphology and elemental composition of recent and fossil cyanobacteria

Ann St. Amand, Richard Hoover, Gregory Jerman, James Coston, Alexei Rozanov

Proceedings Volume 5906, 590603 (2005) https://doi.org/10.1117/12.624854

KEYWORDS: Bacteria, Scanning electron microscopy, Electron microscopes, Charged particle optics, Microscopy, Astrobiology, Planets, Microscopes, Luminescence, Optical microscopy

Read Abstract +

Cyanobacteria (cyanophyta, cyanoprokaryota, and blue-green algae) are an ancient, diverse and abundant group of photosynthetic oxygenic microorganisms. Together with other bacteria and archaea, the cyanobacteria have been the dominant life forms on Earth for over 3.5 billion years. Cyanobacteria occur in some of our planets most extreme environments - hot springs and geysers, hypersaline and alkaline lakes, hot and cold deserts, and the polar ice caps. They occur in a wide variety of morphologies. Unlike archaea and other bacteria, which are typically classified in pure culture by their physiological, biochemical and phylogenetic properties, the cyanobacteria have historically been classified based upon their size and morphological characteristics. These include the presence or absence of heterocysts, sheath, uniseriate or multiseriate trichomes, true or false branching, arrangement of thylakoids, reproduction by akinetes, binary fission, hormogonia, fragmentation, presence/absence of motility etc. Their antiquity, distribution, structural and chemical differentiation, diversity, morphological complexity and large size compared to most other bacteria, makes the cyanobacteria ideal candidates for morphological biomarkers in returned Astromaterials. We have obtained optical (nomarski and phase contrast)/fluorescent (blue and green excitation) microscopy images using an Olympus BX60 compound microscope and Field Emission Scanning Electron Microscopy images and EDAX elemental compositions of living and fossil cyanobacteria. The S-4000 Hitachi Field Emission Scanning Electron Microscope (FESEM) has been used to investigate microfossils in freshly fractured interior surfaces of terrestrial rocks and the cells, hormogonia, sheaths and trichomes of recent filamentous cyanobacteria. We present Fluorescent and FESEM Secondary and Backscattered Electron images and associated EDAX elemental analyses of recent and fossil cyanobacteria, concentrating on representatives of the genera Calothrix, Leptolyngbya, Lyngbya, Planktolyngbya and Oscillatoria.

Proceedings Article | 22 September 2005 Paper

Probabilistic geobiological classification using elemental abundance distributions and lossless image compression in fossils, meteorites, and microorganisms

Michael Storrie-Lombardi, Richard Hoover

Proceedings Volume 5906, 59060K (2005) https://doi.org/10.1117/12.624885

KEYWORDS: Chemical analysis, Principal component analysis, Image compression, Iron, Aluminum, Silicon, Mars, Magnesium, Calcium, Detection and tracking algorithms

Read Abstract +

Last year at this symposium we introduced a strategy for the automated detection of fossils during robotic missions to Mars using both structural and chemical signatures. The strategy employs a measure derived from information theory, lossless compression of photographic images, to estimate the relative complexity of a putative fossil compared to the rock matrix. Following target selection unsupervised multifactor cluster analysis of elemental abundance distributions provides an initial classification of the data. This autonomous classification is then confirmed using a non-linear stochastic neural network to produce a Bayesian estimate of classification accuracy. We have now employed this strategy to explore extant and fossil cyanobacteria from a variety of extreme terrestrial environments and microfossils and abiotic microstructures found in-situ in freshly fractured internal surfaces of carbonaceous meteorite. Elemental abundances (C, N, O, Na, Mg, Al, Si, P, S, Cl, K, Ca, Fe) obtained for both extant and fossil cyanobacteria produce signatures distinguishing them from meteorite targets and from one another. Fossil cyanobacteria exhibit significant loss of C, N, O, P, and Ca and increases in Al, Si, S, and Fe relative to extant organisms. Orgueil structures exhibit decreased abundances for C, N, Na, P, Cl, K, and Ca; and increases in Mg, S, and Fe relative to extant cyanobacteria. Fossil cyanobacteria are distinguished from Orgueil samples by relative increases in Al, Si, and Fe; and by diminished O and Mg. Compression indices verify that variations in random and redundant textural patterns between perceived forms and the background matrix contribute significantly to morphological visual identification. The results provide a quantitative probabilistic methodology for discriminating putatitive fossils from the surrounding rock matrix and from extant organisms using both structural and chemical information. The techniques described appear applicable to the geobiological analysis of meteoritic samples or in situ exploration of the Mars regolith.

Proceedings Article | 22 September 2005 Paper

Anaerobic decomposition of cellulose by alkaliphilic microbial community of Owens Lake, California

Elena Pikuta, Takashi Itoh, Richard Hoover

Proceedings Volume 5906, 590604 (2005) https://doi.org/10.1117/12.624093

KEYWORDS: Microorganisms, Mars, Ecosystems, Oceanography, Carbon monoxide, Carbonates, Hydrogen, Earth's atmosphere, Calcium, Mode conditioning cables

Read Abstract +

Proceedings Article | 22 September 2005 Paper

Fossil microorganisms in Archaean deposits of Northern Karelia

M. Astafieva, R. Hoover, A. Rozanov, A. Vrevskiy

Proceedings Volume 5906, 590606 (2005) https://doi.org/10.1117/12.646847

KEYWORDS: Microorganisms, Electron microscopy, Quartz, Aerospace engineering, Geology, Bacteria, Scanning electron microscopy, Electron microscopes, Basic research, Nomenclature

Read Abstract +

Proceedings Article | 22 September 2005 Paper

The hollow spheres of the Orgueil meteorite: a re-examination

Martine Rossignol-Strick, Richard Hoover, Gregory Jerman, James Coston

Proceedings Volume 5906, 59060M (2005) https://doi.org/10.1117/12.624859

KEYWORDS: Optical spheres, Iron, Spherical lenses, Minerals, Scanning electron microscopy, Chemical elements, Electron microscopes, Carbon, Bacteria, Contamination

Read Abstract +

Proceedings Article | 22 September 2005 Paper

Evidence for liquid water on comets

Robert Sheldon, Richard Hoover

Proceedings Volume 5906, 59060E (2005) https://doi.org/10.1117/12.624092

KEYWORDS: Comets, Liquids, Magnetism, Solar processes, Jupiter, Sun, Convection, Space operations, Plasma, Ions

Read Abstract +

Proceedings Article | 1 November 2004 Paper

Growth of the facultative anaerobes from Antarctica, Alaska, and Patagonia at low temperatures

Elena Pikuta, Richard Hoover

Proceedings Volume 5555, (2004) https://doi.org/10.1117/12.564382

KEYWORDS: Microorganisms, Mars, Proteins, Bacteria, Ecosystems, Astrobiology, Liquids, Organisms, Planets, Sodium

Read Abstract +

Proceedings Article | 1 November 2004 Paper

Fossil signatures using elemental abundance distributions and Bayesian probabilistic classification

Michael Storrie-Lombardi, Richard Hoover

Proceedings Volume 5555, (2004) https://doi.org/10.1117/12.563573

KEYWORDS: Principal component analysis, Silicon, Magnesium, Iron, Aluminum, Visualization, Calcium, Statistical analysis, Stochastic processes, Artificial neural networks

Read Abstract +

Proceedings Article | 1 November 2004 Paper

Indigenous microfossils in carbonaceous meteorites

Richard Hoover, Gregory Jerman, Alexei Rozanov, Paul Sipiera

Proceedings Volume 5555, (2004) https://doi.org/10.1117/12.566491

KEYWORDS: Bacteria, Minerals, Comets, Carbon, Sulfur, Liquids, Iron, Curium, Electron microscopes, Microorganisms

Read Abstract +

Proceedings Article | 1 November 2004 Paper

Astrobiology of comets

Richard Hoover, Elena Pikuta, Nalin Wickramasinghe, Max Wallis, Robert Sheldon

Proceedings Volume 5555, (2004) https://doi.org/10.1117/12.566496

KEYWORDS: Comets, Bacteria, Sun, Liquids, Solar system, Asteroids, Interfaces, Convection, Microorganisms, Astrobiology

Read Abstract +

Proceedings Article | 1 November 2004 Paper

Potential application of anaerobic extremophiles for hydrogen production

Elena Pikuta, Richard Hoover

Proceedings Volume 5555, (2004) https://doi.org/10.1117/12.563703

KEYWORDS: Hydrogen, Bacteria, Carbon monoxide, Hydrogen production, Microorganisms, Pathogens, Bioalcohols, Oxygen, Methane, Iron

Read Abstract +

In processes of the substrate fermentation most anaerobes produce molecular hydrogen as a waste end product, which often controls the culture growth as an inhibitor. Usually in nature the hydrogen is easily removed from an ecosystem, due to its physical features, and an immediate consumption by the secondary anaerobes that sometimes behave as competitors for electron donors; a classical example of this kind of substrate competition in anaerobic microbial communities is the interaction between methanogens and sulfate- or sulfur-reducers. Previously, on the mixed cultures of anaerobes at neutral pH, it was demonstrated that bacterial hydrogen production could provide a good alternative energy source. At neutral pH the original cultures could easily contaminated by methanogens, and the most unpleasant side effect of these conditions is the development of pathogenic bacteria. In both cases the rate of hydrogen production was dramatically decreased since some part of the hydrogen was transformed to methane, and furthermore, the cultivation with pathogenic contaminants on an industrial scale would create an unsafe situation. In our laboratory the experiments with obligately alkaliphilic bacteria producing hydrogen as an end metabolic product were performed at different conditions. The mesophilic, haloalkaliphilic and obligately anaerobic bacterium Spirochaeta americana ASpG1T was studied and various cultivation regimes were compared for the most effective hydrogen production. In a highly mineralized media with pH 9.5-10.0 not many known methanogens are capable of growth, and the probability of developing pathogenic contaminants is theoretically is close to zero (in medicine carbonate- saturated solutions are applied as antiseptics). Therefore the cultivation of alkaliphilic hydrogen producing bacteria could be considered as a safe and economical process for large-scale industrial bio-hydrogen production in the future. Here we present and discuss the experimental data with the rates of hydrogen productivity for S. americana ASpG1 isolated from soda Mono Lake in California.

Proceedings Article | 1 November 2004 Paper

Microbial remains in Middle Proterozoic rocks of Northern Australia

Marina Astafieva, Richard Hoover, Alexei Rozanov, P. Vickers-Rich, A. Wilde

Proceedings Volume 5555, (2004) https://doi.org/10.1117/12.558919

KEYWORDS: Crystals, Iron, Pyrite, Bacteria, Hydrogen, Water, Minerals, Zinc, Sulfur, Spherical lenses

Read Abstract +

Proceedings Article | 1 November 2004 Paper

Salt-tolerant and high-pH-resistant hydrogenase from the haloalkaliphilic, sulfate-reducing bacterium Desulfonatronum thiodismutans

Ekaterina Detkova, Elena Pikuta, Richard Hoover

Proceedings Volume 5555, (2004) https://doi.org/10.1117/12.563702

KEYWORDS: Hydrogen, Bacteria, Sodium, Proteins, Microorganisms, Ions, Nickel, Organisms, Astrobiology, Oxidation

Read Abstract +

Hydrogenase is the key enzyme of energetic metabolism in cells, catalyzing the converse reaction of hydrogen oxidation and responsible for the consumption and excretion of hydrogen in bacteria. Hydrogenases are proteins, most of which contain either nickel and iron or iron alone in their active center. Hydrogenases have been found in many microorganisms, such as methanogenic, acetogenic, nitrogen-fixing, sulfate-reducing, photosynthetic bacteria, and algae that use the hydrogen as an energy source or as an electron sink. Hydrogenases are the subject of wide physiological, biochemical, physico-chemical and genetic studies due to their abilities to produce molecular hydrogen as an alternative source of energy. Despite the large quantity of work dealing with the intracellular and extracellular enzymes of halophilic bacteria, the data about the response of hydrogenases to salts are practically absent. The study of hydrogenase in cell-free extracts of the extremely halophilic eubacterium Acetohalobium arabaticum showed a dramatic increase in the activity of the enzyme at high concentrations of NaCl and KCl (near saturated solutions). Here we present data about hydrogenase in a free-cell extract from the new halo-alkaliphilic sulfate-reducing bacterium Desulfonatronum thiodismutans, which grows on a highly mineralized carbonate-bicarbonate medium in the salinity range from 1 to 7 % NaCl and at pH 8.0-10.0. The studied enzyme was active in concentration range from 0.0 to 4.3 M NaCl with the optimum at 1.0 M NaCl. At 1.0 M NaCl the enzyme expressed 20 % additional activity, with NaCl concentration changing from 2.1 M to 3.4 M, and then the activity decreased and reached a constant level. Although sodium bicarbonate decreases the hydrogenase activity, the enzyme still showed activity at 60 % of the maximum level at concentration in a near saturated solution (1.2 M NaHCO₃). The maximum enzyme activity was observed at pH 9.5 with limits of 7.5 and 11.5, which is practically equal to the pH optimum of bacterial growth. Therefore the hydrogenase of D. thiodismutans is extremely tolerant to high concentrations of sodium salts and resistant to high pH, which makes it a unique subject for biochemical research with the possibility of important biotechnological applications.

Proceedings Article | 10 February 2004 Paper

Framboidal structures in Earth rocks and in astromaterials

Marina Astafieva, Alexei Rozanov, Richard Hoover

Proceedings Volume 5163, (2004) https://doi.org/10.1117/12.513434

KEYWORDS: Pyrite, Crystals, Iron, Bacteria, Sulfur, Oceanography, Water, Minerals, Hematite, Oxidation

Read Abstract +

Proceedings Article | 10 February 2004 Paper

Search for elemental and mineral biomarkers using inelastic neutron scattering spectroscopy (INSS)

Lucian Wielopolski, Richard Hoover, Sudeep Mitra

Proceedings Volume 5163, (2004) https://doi.org/10.1117/12.515229

KEYWORDS: Carbon, Soil science, Calibration, Scattering, Gamma radiation, Sensors, Spectroscopy, Minerals, Chemical elements, Sodium

Read Abstract +

Proceedings Article | 10 February 2004 Paper

Microfossils in CI and CO carbonaceous meteorites

Richard Hoover, Alexei Rozanov, Gregory Jerman, James Costen

Proceedings Volume 5163, (2004) https://doi.org/10.1117/12.513431

KEYWORDS: Bacteria, Minerals, Contamination, Carbon, Polymers, Pyrite, Sulfur, Curium, Liquids, Microorganisms

Read Abstract +

Proceedings Article | 10 February 2004 Paper

Astrobiological significance of chemolithoautotrophic acidophiles

Elena Pikuta, Richard Hoover

Proceedings Volume 5163, (2004) https://doi.org/10.1117/12.513419

KEYWORDS: Bacteria, Microorganisms, Mode conditioning cables, Ecosystems, Hydrogen, Organisms, Planets, Sulfur, Iron, Oxygen

Read Abstract +

Proceedings Article | 10 February 2004 Paper

Atlas of bacteriomorphs in carbonaceous chondrites

Alexei Rozanov, Richard Hoover

Proceedings Volume 5163, (2004) https://doi.org/10.1117/12.515231

KEYWORDS: Bacteria, Minerals, Organisms, Carbonates, Microorganisms, Magnetism, Silica, Iron, Crystals, Astrobiology

Read Abstract +

Proceedings Article | 10 February 2004 Paper

Microorganisms on comets, Europa, and the polar ice caps of Mars

Richard Hoover, Elena Pikuta

Proceedings Volume 5163, (2004) https://doi.org/10.1117/12.513432

KEYWORDS: Microorganisms, Comets, Mars, Liquids, Ecosystems, Water, Satellites, Interfaces, Astrobiology, Space operations

Read Abstract +

Proceedings Article | 26 February 2003 Paper

Red soils on Earth and their significance for Mars

Roland Paepe, Elfi Van Overloop, Richard Hoover, Sophia Nassopoulou, Peter Kafumu, Deqian Wang

Proceedings Volume 4859, (2003) https://doi.org/10.1117/12.457317

KEYWORDS: Climatology, Mars, Climate change, Earth's atmosphere, Planets, Oxygen, Vegetation, Composites, Carbonates, Astatine

Read Abstract +

Proceedings Article | 26 February 2003 Paper

Anaerobic halo-alkaliphilic bacterial community of athalassic hypersaline from Mono Lake and Owens Lake in California

Elena Pikuta, Ekaterina Detkova, Asim Bej, Damien Marsic, Richard Hoover

Proceedings Volume 4859, (2003) https://doi.org/10.1117/12.463322

KEYWORDS: Carbonates, Ions, Sodium, Bacteria, Hydrogen, Minerals, Mars, Mode conditioning cables, Statistical analysis, Astrobiology

Read Abstract +

The bacterial diversity of microbial extremophiles from the meromictic, hypersaline Mono Lake and a small evaporite pool in Owens Lake of California was studied. In spite of these regions had differing mineral background and different concentrations of NaCl in water they contain the same halo- alkaliphiles anaerobic bacterial community. Three new species of bacteria were detected in this community: primary anaerobe, dissipotrophic saccharolytic spirochete Spirochaeta americana strain AspG1^T, primary anaerobe which is proteolytic Tindallia californiensis strain APO^T, and secondary anaerobe, hydrogen using Desulfonatronum thiodismutans strain MLF1^T, which is sulfate- reducer with chemo-litho-autotrophic metabolism. All of these bacteria are obligate alkaliphiles and dependent upon Na⁺ ions and CO₃^2-ions in growth mediums. It is interesting that closest relationships for two of these species were isolates from samples of equatorial African soda Magadi lake: Spirochaeta americana AspG1^T has 99.4% similarity on 16S rDNA- analyses with Spirochaeta alkalica Z- 7491^T, and Tindallia californiensis APO^T has 99.1% similarity with Tindallia magadiensis Z-7934^T. But result of DNA-DNA- hybridization demonstrated less then 50% similarity between Spirochaeta americana AspG1^T and Spirochaeta alkalica Z-7491^T. Percent of homology between Tindallia californiensis APO^T and Tindallia magadiensis Z-7934^T is only 55%. The sulfate-reducer from the alkalic anaerobic community of Magadi lake Desulfonatronovibrio hydrogenovorans Z-7935^T was phylogenetically distant from this sulfate-reducer in Mono lake, but genetically closer (99.7% similarity) to the sulfate-reducer, isolated from Central Asian alkalic lake Khadyn in Siberia Desulfonatronum lacustre Z-7951^T. The study of key enzymes (hydrogenase and CO- hydrogenase) in Tindallia californiensis APO^T and Desulfonatronum thiodismutans MLF1^T showed the presence of high activity of both the enzymes in first and only hydrogenase in second isolate. These results indicate that the athalassic, soda Mono and Owens lakes contain an anaerobic alkaliphilic bacterial community with common ancestors of geographically distant regions, but very same in morphological and functional aspects. As suggested Zavarzin, halo- alkaliphiles may represent relics of microbial life from the early formation of the ancient Earth before the Neoproterozoic period.

Proceedings Article | 26 February 2003 Paper

Sterile robotic Mars soil analyzer

Gilbert Levin, Joseph Miller, Patricia Straat, Richard Hoover

Proceedings Volume 4859, (2003) https://doi.org/10.1117/12.457312

KEYWORDS: Mars, Lawrencium, Space operations, Biology, Robotics, Soil science, Liquids, Microorganisms, Organisms, Chemical analysis

Read Abstract +

Proceedings Article | 26 February 2003 Paper

Biomarkers and microfossils in the Murchison, Rainbow, and Tagish Lake meteorites

Richard Hoover, Gregory Jerman, Alexei Rozanov, Paul Davies

Proceedings Volume 4859, (2003) https://doi.org/10.1117/12.463321

KEYWORDS: Carbon, Bacteria, Asteroids, Carbonates, Iron, Microorganisms, Contamination, Polymers, Astrobiology, X-rays

Read Abstract +

Proceedings Article | 26 February 2003 Paper

Palaeodynamic sedimentary cycles on Mars in resonance with short similar cycles on Earth

Elfi Van Overloop, Roland Paepe, Richard Hoover

Proceedings Volume 4859, (2003) https://doi.org/10.1117/12.457328

KEYWORDS: Mars, Climatology, Sun, Cadmium, Climate change, Genetics, Autoregressive models, Photography, Stochastic processes, Cameras

Read Abstract +

Calculating palaeoclimatic cycles on a wide range of geological parameters of the Earth revealed the absolute dependence of climatic change on planetary and Sun orbital characteristics and resonances. Mars Orbiter Camera (MOC) images MOC2_148 and MOC2_300, taken from huge canyons near the north polar region clearly show a periglacial permafrost sequence of sedimentary layers which are of different repetitive thicknesses. The fact that such layers have been rhythmically deposited inheres the existence of a fossil or palaeo-dynamic sedimentary environment. Since thickness of the sediment layers differs, the relative sedimentation rate (Relative-Sediment-Deposit-Genetic-Rate (RSDGR)) is taken for a standard parameter. Application of two especially for this purpose tested successive AR algorithms (ExSpect-Matlab) reveals the existence of short RSDGR cycles on Mars ranging from 1,000 years through 10,000 and 40,000 years. The short-term cycles (less than 10,000 years) coincide with the small palaeoclimatic changes on Earth, defined by planetary resonances and Sun activity; instead the larger ones correspond with the larger desertification cycles (glacial-interglacial) on Earth, depending on planetary orbital behavior (the so-called Milankovitch cycles). Time span simulations were executed on the Mars sediment series, corresponding to well known Stages of the Quaternary System on Earth (2.4 Million years and less) and on the large Geological Era’s of the Earth (4.6 Billion years and less). It was found that only small cyclicities (400,000 and less) could be calculated on basis of the RSDGR derived from MOC2_148 and MOC2_300 images. No correspondence with known cyclicities on Earth occur when deposition time span is simulated as being longer than 2.4 million years. This fact leads to the assumption that RSDGR events on Mars cover a much shorter time span. Since the sediment series lay on the surface of Mars, the genetic geological dynamics will first be described in detail. Furthermore, it will be investigated by the same method how recent the surface depositional event may be. Calculation results in an approximative age of 125,000 years, called on Earth the “Last Glacial-Last Interglacial Cycle”. Correspondence with Holocene (last 12500 years) cycles on Earth prove that the RSDGR process is active today.

Proceedings Article | 30 January 2003 Paper

Psychrophiles and astrobiology: microbial life of frozen worlds

Elena Pikuta, Richard Hoover

Proceedings Volume 4939, (2003) https://doi.org/10.1117/12.501866

Read Abstract +

Most bodies of our Solar System are "Frozen Worlds" where the prevailing surface temperature remains at or below freezing. On Earth there are vast permanently frozen regions of permafrost, polar ice sheets, and glaciers and the deep oceans and deep-sea marine sediments have remained at 2 - 4°C for eons. Psychrophilic and psychrotrophic microbiota that inhabit these regimes provide analogs for microbial life that might inhabit ice sheets and permafrost of Mars, comets, or the ice/water interfaces or sediments deep beneath the icy crusts of Europa, Callisto, or Ganymede. Cryopreserved micro-organisms can remain viable (in a deep anabiotic state) for millions of years frozen in permafrost and ice. Psychrophilic and psychrotrophic (cold-loving) microbes can carry out metabolic processes in water films and brine, acidic, or alkaline chanels in permafrost or ice at temperatures far below 0°C. These microbes of the cryosphere help define the thermal and temporal limits of life on Earth and may provide clues to where and how to search for evidence of life elsewhere in the Cosmos. Astrobiologists at the NASA Marshall Space Flight Center have collected microbial extremophiles from the Pleistocene ice wedges and frozen thermokarst ponds from the Fox Permafrost Tunnel of Alaska. Microbes have also been isolated from samples of Magellanic Penguin guano from Patagonia; deep-sea marine muds near hydrothermal vents; snow and permafrost from Siberia, and deep ice cores, ice-bubble and cryoconite rocks of the Central Antarctic Ice Sheet. These samples have yielded microbial extremophiles representing a wide variety of anaerobic bacteria and archaea. These microbes have been isolated, cultured, characterized and analyzed by phylogenetic and genomic methods. Images were obtained by Phase Contrast, Environmental, Field Emission Scanning and Transmission Electron Microscopes to study the ultra-microstructure and elemental distribution in the composition of these micro-organisms. We consider the Astrobiological significance of the Fox Tunnel with its rich assemblage of frozen microbes as proxy for developing techniques that may help optimize the search for evidence of life in the permafrost of Mars. We provide images of a novel anaerobic, heterotrophic, psychrotrophic bacterium (str.FTR1) isolated in pure culture from the Fox Tunnel. We also describe novel psychrotrophs isolated from guano of the Magellanic penguin (Spheniscus magellanicus) from the southern tip of Patagonia. These strains PmagG1 and PPP2) represent new species and genera of anaerobic microbes that grow at very low temperatures. The lowest limit for growth without morphological changes of str.PmagG1 is −4°C.

Proceedings Article | 30 January 2003 Paper

Microfossils, biominerals, and chemical biomarkers in meteorites

Richard Hoover, Alexei Rozanov

Proceedings Volume 4939, (2003) https://doi.org/10.1117/12.501868

Read Abstract +

Proceedings Article | 30 July 2002 Paper

Astrobiology: traces of life in the cosmos

Richard Hoover, Alexei Rozanov

Proceedings Volume 4765, (2002) https://doi.org/10.1117/12.489771

KEYWORDS: Mars, Bacteria, Carbon, Comets, Microorganisms, Minerals, Astrobiology, Ecosystems, Carbonates, Planets

Read Abstract +

The discovery of traces of life in the ancient Mars meteorite triggered the development of the rapidly emerging field of Astrobiology. Astrobiologists are seeking to develop conclusive methods to recognize biosignatures and microfossils of bacteria and other microbiota as well as to understand the spatial, temporal, environmental and chemical limitations of microbial extremophiles. Recent discoveries have revealed the great distribution and diversity of microbial extremophiles on Earth and profoundly increased the probability that life may exist elsewhere in the Cosmos. The rapidly emerging science of Bacterial Paleontology has provided important new information critical to the recognition of fossil bacteria on Earth and in Astromaterials. We have recently conducted independent scanning electron microscopy and x-ray analysis investigations in the US and Russia in order to better understand the morphology and chemical composition of microfossils in ancient terrestrial rocks and carbonaceous meteorites. In this paper, we review some aspects of microbial extremophiles of Earth as modals for life on other bodies of the Solar System. We consider several of the important chemical, mineral and morphological biomarkers that provide definitive evidence of biogenic activity in ancient rocks and meteorites. We present Environmental Scanning Electron Microscope images of microfossils found in-situ in freshly fractured meteorite surfaces and describe Energy Dispersive Spectroscopy and Link microprobe analysis of the chemical elements in the mineralized and/or kerogenous microfossils and meteorite rock matrix. We also discuss technqiues and methods that may be used to help discriminate indigenous microfosils from recent terrestrial contaminants. We will also present new data from our in-situ investigations of living cyanobacteria and bacteria and freshly broken surfaces of terrestrial rocks and meteorites. Comparative analysis of these images are interpreted as providing dramatic evidence of indigenous microfossils of magnetotactic bacteria, cyanobacteria, and acritarchs in the Nogoya, Efremovka, Orgueil, Murchison and Tagish Lake Meteorites. Many of the forms in carbonaceous meteorites are large and complex providing strong evidence of biogenicity. Many of the forms found in carbonaceous meteorites are strikingly similar to microfossils of bacteria, cyanobacteria and fungi we know from the Cambrian phosphorites of Khubsugul, Mongolia and high carbon Phanerozoic and Precambrian rocks of the Siberian and Russian Platforms. Some meteorite microfossil assemblages are consistent with known characteristics of distinct microbial life cycles and reproductive stages of Nostocacean cyanobacteria. We also recognize assemblages consistent with microbial ecosystems we studied in permafrost and cryoconite communities of Antarctica, Alaska and Siberia and microfossil ecosystems from the Cambrian of Mongolia.

Proceedings Article | 5 February 2002 Paper

Cloning of the 16S ribosomal RNA gene of a psychrophilic bacterium from the Alaskan Fox Permafrost Tunnel

Damien Marsic, Elena Pikuta, Richard Hoover, Joseph Ng

Proceedings Volume 4495, (2002) https://doi.org/10.1117/12.454764

KEYWORDS: Astrobiology, Microorganisms, Organisms, Polymers, Macromolecules, Genetics, Molecular mechanisms, Liquids, Bioalcohols, Bacteria

Read Abstract +

Proceedings Article | 5 February 2002 Paper

Mineralogical and petrological analyses of two possible achondrite meteorites recovered from the Thiel Mountains, Antarctica

Paul Sipiera, Richard Hoover, Gregory Jerman

Proceedings Volume 4495, (2002) https://doi.org/10.1117/12.454767

KEYWORDS: Crystals, Point spread functions, Metals, Mineralogy, Petrology, Photomicroscopy, Analytical research, Diagnostics, Statistical analysis, Photography

Read Abstract +

Proceedings Article | 5 February 2002 Paper

Anaerobic psychrophiles from Alaska, Antarctica, and Patagonia: implications to possible life on Mars and Europa

Richard Hoover, Elena Pikuta, Damien Marsic, Joseph Ng

Proceedings Volume 4495, (2002) https://doi.org/10.1117/12.454768

KEYWORDS: Microorganisms, Astrobiology, Mars, Bacteria, Ecosystems, Planets, Proteins, Physiology, Comets, Scanning electron microscopy

Read Abstract +

Microorganisms preserved within the permafrost, glaciers, and polar ice sheets of planet Earth provide analogs for microbial life forms that may be encountered in ice or permafrost of Mars, Europa, Callisto, Ganymede, asteroids, comets or other frozen worlds in the Cosmos. The psychrophilic and psychrotolerant microbes of the terrestrial cryosphere help establish the thermal and temporal limitations of life on Earth and provide clues to where and how we should search for evidence of life elsewhere in the Universe. For this reason, the cold-loving microorganisms are directly relevant to Astrobiology. Cryopreserved microorganisms can remain viable (in deep anabiosis) in permafrost and ice for millions of years. Permafrost, ice wedges, pingos, glaciers, and polar ice sheets may contain intact ancient DNA, lipids, enzymes, proteins, genes, and even frozen and yet viable ancient microbiota. Some microorganisms carry out metabolic processes in water films and brine, acidic, or alkaline channels in permafrost or ice at temperatures far below 0 degree(s)C. Complex microbial communities live in snow, ice-bubbles, cryoconite holes on glaciers and ancient microbial ecosystems are cryopreserved within the permafrost, glaciers, and polar caps. In the Astrobiology group of the NASA Marshall Space Flight Center and the University of Alabama at Huntsville, we have employed advanced techniques for the isolation, culture, and phylogenetic analysis of many types of microbial extremophiles. We have also used the Environmental Scanning Electron Microscope to study the morphology, ultra-microstructure and chemical composition of microorganisms in ancient permafrost and ice. We discuss several interesting and novel anaerobic microorganisms that we have isolated and cultured from the Pleistocene ice of the Fox Tunnel of Alaska, guano of the Magellanic Penguin, deep-sea sediments from the vicinity of the Rainbow Hydrothermal Vent and enrichment cultures from ice of the Patriot Hills of Antarctica. The microbial extremophiles recovered from permafrost, ice, cold pools and deep-sea sediments may provide information relevant to the question of how and where we should search for evidence of extant or extinct microbial life elsewhere in the Cosmos.

Proceedings Article | 5 February 2002 Paper

Bacterial paleontology for astrobiology

Alexei Rozanov, Elena Zhegallo, Galina Ushatinskaya, Yulia Shuvalova, Richard Hoover

Proceedings Volume 4495, (2002) https://doi.org/10.1117/12.454765

KEYWORDS: Bacteria, Microorganisms, Astrobiology, Minerals, Crystals, Fungi, Carbonates, Scanning electron microscopy, Iron, Chemical analysis

Read Abstract +

Proceedings Article | 5 February 2002 Paper

Computing periodicities in Mars sediment time series

Elfi Van Overloop, Roland Paepe, Richard Hoover

Proceedings Volume 4495, (2002) https://doi.org/10.1117/12.454776

KEYWORDS: Mars, Climatology, Astronomy, Stochastic processes, Signal processing, Autoregressive models, Planets, Sun, Climate change, Astrobiology

Read Abstract +

Proceedings Article | 5 February 2002 Paper

Chemical biomarkers and microfossils in carbonaceous meteorites

Richard Hoover, Alexei Rozanov

Proceedings Volume 4495, (2002) https://doi.org/10.1117/12.454756

KEYWORDS: Mars, Bacteria, Carbon, Microorganisms, Carbonates, Comets, Organisms, Minerals, Crystals, Contamination

Read Abstract +

Proceedings Article | 5 February 2002 Paper

Comparison of snowball Earth and Mars conditions

Roland Paepe, Elfi Van Overloop, Richard Hoover

Proceedings Volume 4495, (2002) https://doi.org/10.1117/12.454775

KEYWORDS: Mars, Climatology, Climate change, Planets, Satellite imaging, Earth observing sensors, Satellites, Earth's atmosphere, Genetics, Astrobiology

Read Abstract +

Proceedings Article | 5 February 2002 Paper

Sulfate- and sulfur-reducing bacteria as terrestrial analogs for microbial life on Jupiter's Satellite Io

Elena Pikuta, Richard Hoover

Proceedings Volume 4495, (2002) https://doi.org/10.1117/12.492485

KEYWORDS: Bacteria, Sulfur, Microorganisms, Carbon dioxide, Hydrogen, Oxygen, Jupiter, Analog electronics, Satellites, Oxidation

Read Abstract +

Observations from the Voyager and Galileo spacecraft have revealed Jupiter's moon Jo to be the most volcanically active body of our Solar System. The Galileo Near Infrared Imaging Spectrometer (NIMS) detected extensive deposits of sulfur compounds, elemental sulfur and SO2 frost on the surface of To. There are extreme temperature variations on Jo' S surface - ranging from -130 °C to over +2000 °C at the Pillan Patera volcanic vent. The active volcanoes, fumaroles, calderas, and lava lakes and vast sulfur deposits on this frozen moon indicate that analogs of sulfur- and sulfate-reducing bacteria might inhabit Jo. Hence Jo may have great significance to Astrobiology. Earth' s life forms that depend on sulfur respiration are members of two domainsBacteria and Archaea. Two basic links of the biogeochemical sulfur cycle of Earth have been studied: a. the sulfur oxidizing process (occurring at aerobic conditions) and b. the process of sulfur-reduction to hydrogen sulfide (anaerobic conditions). Sulfate-reducing bacteria (StRB) and sulfur-reducing bacteria (SrRB) are responsible for anaerobic reducing processes. At the present time the systematics of StRB include over 112 species distributed into 35 genera of Bacteria and Archaea. Moderately thermophilic and mesophilic SrRB belong to the Bacteria. The hyperthermophilic SrRB predominately belong to the domain Archaea and are included in the genera: Pyrodictium, Thermoproteus, Pyrobaculum, Thermophilum, Desulfurococcus, and Thermodiscus. The StRB and SrRB use a wide spectrum of substrates as electron donors for lithotrophic and heterotrophic type nutrition. The electron acceptors for the StRB include: sulfate, thiosulfate, sulfite, sulfur, dithionite, tetrathionate, sulfur monoxide, iron, nitrite, selenite, fumarate, oxygen, carbon dioxide, and chlorinecontaining phenol compounds. The Sulfate- and Sulfur-reducing bacteria are widely distributed in anaerobic ecosystems, including extreme environments like hot springs, deep-sea hydrothermal vents, soda and high salinity lakes, and cryo-environments. Furthermore, the StRB and SrRB have Astrobiological significance as these anaerobic extremophiles may represent the dominant relic life forms that inhabited our planet during the extensive volcanic activity in the Earths early evolutionary period.

Proceedings Article | 3 August 2001 Paper

Evidence for biomarkers and microfossils in ancient rocks and meteorites

Richard Hoover, Alexei Rozanov

Proceedings Volume 4273, (2001) https://doi.org/10.1117/12.435380

KEYWORDS: Mars, Microorganisms, Carbon, Bacteria, Comets, Contamination, Minerals, Liquids, Organisms, Chemical analysis

Read Abstract +

Proceedings Article | 29 December 2000 Paper

Meteorites and microbes: meteorite collection and ice sampling at Patriot Hills, Thiel Mountains, and South Pole, Antarctica

Paul Sipiera, Richard Hoover, Gregory Jerman

Proceedings Volume 4137, (2000) https://doi.org/10.1117/12.411617

KEYWORDS: Microorganisms, Point spread functions, Photography, Global Positioning System, Liquids, Astrobiology, Carbonates, Contamination, Eye, Crystals

Read Abstract +

Proceedings Article | 13 December 2000 Paper

Sounding rocket mission to study the solar soft x-ray and EUV emission using transition-edge sensor technology

Kolo Wamba, Arthur Walker, Dennis Martinez-Galarce, Sae Woo Nam, Kent Irwin, Steven Deiker, Blas Cabrera, Lawrence Lesyna, Stephen Powell, Aaron Miller, David Robertson, Paul Boerner, Phillip Baker, Troy Barbee, Richard Hoover

Proceedings Volume 4140, (2000) https://doi.org/10.1117/12.409134

KEYWORDS: Telescopes, Plasma, Sensors, Iron, Extreme ultraviolet, Rockets, Solar processes, Multilayers, X-rays, Monte Carlo methods

Read Abstract +

SPIE Journal Paper | 1 April 2000

High resolution imaging with multilayer telescopes: resolution performance of the MSSTA II Telescopes

Dennis Martinez-Galarce, Arthur Walker, David Gore, Charles Kankelborg, Richard Hoover, Troy Barbee, Paul Boerner

OE, Vol. 39, Issue 04, (April 2000) https://doi.org/10.1117/12.10.1117/1.602468

KEYWORDS: Telescopes, Image resolution, Mirrors, Space telescopes, Multilayers, Spatial resolution, Extreme ultraviolet, Iron, Error analysis, Diffraction

Proceedings Article | 30 December 1999 Paper

Biomorphic structures in Mighei carbonaceous chondrite

Richard Hoover, Alexei Rozanov

Proceedings Volume 3755, (1999) https://doi.org/10.1117/12.375070

KEYWORDS: Sulfur, Iron, Astrobiology, Chemical analysis, Statistical analysis, Magnesium, Silicon, Spherical lenses, Bacteria, Neck

Read Abstract +

Proceedings Article | 30 December 1999 Paper

The ExSpect-Matlab or AR (autoregressive) PSD (power spectral density) cyclicity calucations method for sediment times series, interfering key beds, and fossil soils

Elfi Van Overloop, Roland Paepe, Richard Hoover

Proceedings Volume 3755, (1999) https://doi.org/10.1117/12.375072

KEYWORDS: Mars, Minerals, Astronomy, Autoregressive models, Climatology, Short wave infrared radiation, Signal processing, Planets, Spectroscopy, Absorption

Read Abstract +

Proceedings Article | 30 December 1999 Paper

Environmental scanning electron microscopy investigations of ancient microorganisms from deep ice above Lake Vostok

Richard Hoover, Sabit Abyzov, Michael Ivanov

Proceedings Volume 3755, (1999) https://doi.org/10.1117/12.375076

KEYWORDS: Microorganisms, Scanning electron microscopy, Mars, Bacteria, Electron microscopes, Astrobiology, Analog electronics, Comets, Chemical analysis, Sensors

Read Abstract +

Proceedings Article | 30 December 1999 Paper

Gene cloning of the 18S rRNA of an ancient viable moss from the permafrost of northeastern Siberia

Damien Marsic, Richard Hoover, David Gilichinsky, Joseph Ng

Proceedings Volume 3755, (1999) https://doi.org/10.1117/12.375074

KEYWORDS: Tissues, Polymers, Organisms, Genetics, Microorganisms, Biological research, Magnesium, Liquids, Databases, Annealing

Read Abstract +

Proceedings Article | 30 December 1999 Paper

Interference or comparison between Mars and terrestrial landscapes as evidence of water and its cycles

Roland Paepe, Elfi Van Overloop, Richard Hoover

Proceedings Volume 3755, (1999) https://doi.org/10.1117/12.375071

KEYWORDS: Mars, Planets, Climatology, Vegetation, Climate change, Earth's atmosphere, Double patterning technology, Methane, Oceanography, Astrobiology

Read Abstract +

Proceedings Article | 30 December 1999 Paper

Microorganisms and unicellular algae in the ice sheet of Antarctica

Sabit Abyzov, Irina Mitskevich, Margarita Poglazova, Richard Hoover, Mikhail Ivanov

Proceedings Volume 3755, (1999) https://doi.org/10.1117/12.375075

KEYWORDS: Microorganisms, Oceanography, Microbiology, Organisms, Microscopy, Luminescence, Silicon, Scanning electron microscopy, Proteins, Yeast

Read Abstract +

Proceedings Article | 30 December 1999 Paper

Astrobiological significance of microorganisms in permafrost and ice

Richard Hoover

Proceedings Volume 3755, (1999) https://doi.org/10.1117/12.375087

KEYWORDS: Microorganisms, Mars, Ecosystems, Bacteria, Astrobiology, Analog electronics, Comets, Scanning electron microscopy, Planets, Electron microscopes

Read Abstract +

Proceedings Article | 30 December 1999 Paper

Microbiota of the Bogotol graphites

Alexei Rozanov, Elena Zhegallo, Richard Hoover

Proceedings Volume 3755, (1999) https://doi.org/10.1117/12.375085

KEYWORDS: Fungi, Carbon, Carbonates, Spherical lenses, Microorganisms, Crystals, Minerals, Organisms, Spine, Optical spheres

Read Abstract +

Proceedings Article | 29 September 1999 Paper

High-resolution imaging with multilayer telescopes: resolution performance of the MSSTA II telescopes

Dennis Martinez-Galarce, Arthur Walker, David Gore, Charles Kankelborg, Richard Hoover, Troy Barbee, Paul Boerner

Proceedings Volume 3766, (1999) https://doi.org/10.1117/12.363662

KEYWORDS: Telescopes, Space telescopes, Mirrors, Image resolution, Spatial resolution, Point spread functions, Diffraction, Iron, Extreme ultraviolet, Optical testing

Read Abstract +

Proceedings Article | 29 September 1999 Paper

Chromospheric/coronal spectroheliograph

Paul Boerner, Arthur Walker, Richard Hoover, Troy Barbee, Dennis Martinez-Galarce

Proceedings Volume 3766, (1999) https://doi.org/10.1117/12.363640

KEYWORDS: Telescopes, Iron, Plasma, Extreme ultraviolet, Solar processes, Multilayers, Temperature metrology, Magnesium, Coronagraphy, Mirrors

Read Abstract +

Proceedings Article | 6 July 1998 Paper

Further evidence of microfossils in carbonaceous meteorites

Richard Hoover, Alexei Rozanov, Stanislav Zhmur, Vladimir Gorlenko

Proceedings Volume 3441, (1998) https://doi.org/10.1117/12.319839

KEYWORDS: Microorganisms, Scanning electron microscopy, Chemical elements, Minerals, Bacteria, Contamination, Electron microscopes, Planets, Carbon, Astrobiology

Read Abstract +

Proceedings Article | 6 July 1998 Paper

Phosphate biomineralization of cambrian microorganisms

David McKay, Alexei Rozanov, Richard Hoover, Frances Westall

Proceedings Volume 3441, (1998) https://doi.org/10.1117/12.319834

KEYWORDS: Microorganisms, Organisms, Bacteria, Crystals, Calcite, Apatite, Minerals, Scanning electron microscopy, Mars, Spherical lenses

Read Abstract +

Proceedings Article | 11 July 1997 Paper

Meteorites, microfossils, and exobiology

Richard Hoover

Proceedings Volume 3111, (1997) https://doi.org/10.1117/12.278766

KEYWORDS: Microorganisms, Carbon, Comets, Contamination, Iron, Chemical elements, Organisms, Planets, Optical spheres, Minerals

Read Abstract +

The discovery of evidence for biogenic activity and possible microfossils in a Martian meteorite may have initiated a paradigm shift regarding the existence of extraterrestrial microbial life. Terrestrial extremophiles that live in deep granite and hydrothermal vents and nanofossils in volcanic tuffs have altered the premise that microbial life and microfossils are inconsistent with volcanic activity and igneous rocks. Evidence for biogenic activity and microfossils in meteorites can no longer be dismissed solely because the meteorite rock matrix is not sedimentary. Meteorite impact-ejection and comets provide mechanisms for planetary cross-contamination of biogenic chemicals, microfossils, and living microorganisms. Hence, previously dismissed evidence for complex indigenous biochemicals and possible microfossils in carbonaceous chondrites must be re- examined. Many similar, unidentifiable, biological-like microstructures have been found in different carbonaceous chondrites and the prevailing terrestrial contaminant model is considered suspect. This paper reports the discovery of microfossils indigenous to the Murchison meteorite. These forms were found in-situ in freshly broken, interior surfaces of the meteorite. Environmental Scanning Electron Microscope and optical microscopy images indicate that a population of different biological-like forms are represented. Energy Dispersive Spectroscopy reveals these forms have high carbon content overlaying an elemental distribution similar to the matrix. Efforts at identification with terrestrial microfossils and microorganisms were negative. Some forms strongly resemble bodies previously isolated in the Orgueil meteorite and considered microfossils by prior researchers. The Murchison forms are interpreted to represent an indigenous population of the preserved and altered carbonized remains (microfossils) of microorganisms that lived in the parent body of this meteorite at diverse times during the past 4.5 billion years (Gy).

Proceedings Article | 11 July 1997 Paper

Progress in the development of far-ultraviolet etalons

Marilyn Bruner, Jean-Pierre Wuelser, Muamer Zukic, Richard Hoover

Proceedings Volume 3113, (1997) https://doi.org/10.1117/12.278874

KEYWORDS: Fabry–Perot interferometers, Optical coatings, Reflectivity, Ultraviolet radiation, Multilayers, Magnesium fluoride, Solar processes, Calibration, Far ultraviolet, Refractive index

Read Abstract +

Proceedings Article | 25 November 1996 Paper

Solar Chromospheric and Coronal Explorer

Arthur Walker, Philip Scherrer, Richard Hoover, Einar Tandberg-Hanssen, Troy Barbee, James Ling, R. MacQueen, J. Gethyn Timothy, Paul Adamson, Mike Mennzel, John Petheram, Paul Shattuck

Proceedings Volume 2804, (1996) https://doi.org/10.1117/12.259723

KEYWORDS: Solar processes, Iron, Magnetism, Mirrors, Coronagraphy, Crystals, Space operations, Solar energy, Sun, Telescopes

Read Abstract +

SPIE Journal Paper | 1 May 1996

Design and fabrication of multilayer reflective filters for a Ritchey-Chretien Lyman-alpha telescope

Jungho Park, Muamer Zukic, Michele McColgan, Charles Keffer, Douglas Torr, Richard Hoover

OE, Vol. 35, Issue 05, (May 1996) https://doi.org/10.1117/12.10.1117/1.600684

KEYWORDS: Telescopes, Reflectivity, Mirrors, Optical filters, Reflector telescopes, Space telescopes, Optical instrument design, Reflection, Multilayers, Silicon carbide

Proceedings Article | 20 June 1995 Paper

Calibration of multilayer mirrors for the Multi-Spectral Solar Telescope Array II

Charles Kankelborg, James Plummer, Dennis Martinez-Galarce, Ray O'Neal, Craig DeForest, Arthur Walker, Troy Barbee, J. Weed, Richard Hoover, Forbes Powell

Proceedings Volume 2515, (1995) https://doi.org/10.1117/12.212609

KEYWORDS: Mirrors, Reflectivity, Calibration, Multilayers, Telescopes, Solar telescopes, Monochromators, Sensors, Space telescopes, Signal detection

Read Abstract +

Proceedings Article | 20 June 1995 Paper

Multi-Spectral Solar Telescope Array IX: quantitative measurements of the solar corona

Craig DeForest, Arthur Walker, Maxwell Allen, Richard Hoover, Troy Barbee

Proceedings Volume 2515, (1995) https://doi.org/10.1117/12.212596

KEYWORDS: Telescopes, Solar processes, Plasma, Solar telescopes, Coronagraphy, Space telescopes, Calibration, Extreme ultraviolet, Aluminum, Temperature metrology

Read Abstract +

Proceedings Article | 20 June 1995 Paper

Fabrication of multilayer optics by sputtering: application to EUV optics with greater than 30% normal reflectance

Palmer Peters, Richard Hoover, Richard Watts, Charles Tarrio, Arthur Walker

Proceedings Volume 2515, (1995) https://doi.org/10.1117/12.212625

KEYWORDS: Sputter deposition, Multilayers, EUV optics, Reflectivity, Niobium, Plasma, Extreme ultraviolet, X-ray optics, Contamination, Gases

Read Abstract +

Proceedings Article | 20 June 1995 Paper

Optical focusing and alignment of the Multi-Spectral Solar Telescope Array II payload

David Gore, James Hadaway, Richard Hoover, Arthur Walker, Charles Kankelborg

Proceedings Volume 2515, (1995) https://doi.org/10.1117/12.212618

KEYWORDS: Telescopes, Space telescopes, Mirrors, Optical instrument design, Diffraction, Solar telescopes, Sun, Rockets, Extreme ultraviolet, Modulation transfer functions

Read Abstract +

Proceedings Article | 20 June 1995 Paper

Multi-Spectral Solar Telescope Array VIII: the second flight

Arthur Walker, Maxwell Allen, Craig DeForest, Charles Kankelborg, Dennis Martinez-Galarce, James Plummer, Richard Hoover, Troy Barbee, David Gore

Proceedings Volume 2515, (1995) https://doi.org/10.1117/12.212587

KEYWORDS: Space telescopes, Iron, Telescopes, Solar processes, Coronagraphy, Image resolution, Spatial resolution, Temperature metrology, Reflector telescopes, Solar telescopes

Read Abstract +

Proceedings Article | 20 June 1995 Paper

Design and performance of thin foil XUV filters for the Multi-Spectral Solar Telescope Array II

James Plummer, Craig DeForest, Dennis Martinez-Galarce, Charles Kankelborg, David Gore, Ray O'Neal, Arthur Walker, Forbes Powell, Richard Hoover, Troy Barbee, J. Weed

Proceedings Volume 2515, (1995) https://doi.org/10.1117/12.212623

KEYWORDS: Optical filters, Telescopes, Extreme ultraviolet, Aluminum, Calibration, Iron, Mirrors, Visible radiation, Sensors, Photodiodes

Read Abstract +

Proceedings Article | 11 November 1994 Paper

High-resolution x-ray spectroscopy with a rocket-borne cosmic x-ray microcalorimeter spectrograph

Arthur Walker, Aharon Kapitulnik, Richard Hoover, Lawrence Lesyna, Melville Ulmer

Proceedings Volume 2279, (1994) https://doi.org/10.1117/12.193129

KEYWORDS: X-rays, Spectrographs, Mirrors, Spectroscopy, Rockets, Silicon, Hydrogen, Iron, X-ray astronomy, Clouds

Read Abstract +

Proceedings Article | 11 November 1994 Paper

Astronomical observations with normal incidence multilayer optics IV: selection of spectral lines

Arthur Walker, James Plummer, Richard Hoover, Troy Barbee

Proceedings Volume 2279, (1994) https://doi.org/10.1117/12.193153

KEYWORDS: Multilayers, Telescopes, Iron, Mirrors, Solar processes, Extreme ultraviolet, Astronomical imaging, Astronomy, Reflection, Spectral resolution

Read Abstract +

Proceedings Article | 4 October 1994 Paper

Development of the Water Window Imaging X-Ray Microscope

Richard Hoover, David Shealy, Arthur Walker, Phillip Baker, Nicola Grupido, George Gutman, Troy Barbee

Proceedings Volume 2270, (1994) https://doi.org/10.1117/12.188828

KEYWORDS: Microscopes, X-rays, Multilayers, X-ray imaging, Mirrors, X-ray telescopes, X-ray optics, Reflectivity, Spatial resolution, Optical coatings

Read Abstract +

Proceedings Article | 15 February 1994 Paper

Stray light analysis of a reflecting UV coronagraph/polarimeter with multilayer optics

Silvano Fineschi, Marco Romoli, Richard Hoover, Phillip Baker, Muamer Zukic, Jongmin Kim, Arthur Walker

Proceedings Volume 2010, (1994) https://doi.org/10.1117/12.168591

KEYWORDS: Mirrors, Coronagraphy, Multilayers, Ultraviolet radiation, Coating, Telescopes, Solar processes, X-rays, Bidirectional reflectance transmission function, Scattering

Read Abstract +

Proceedings Article | 15 February 1994 Paper

Fabrication and test of a wide-field H-Lyman alpha coronagraph/polarimeter

Richard Hoover, Arthur Walker, Silvano Fineschi, Phillip Baker, Muamer Zukic, Jongmin Kim

Proceedings Volume 2010, (1994) https://doi.org/10.1117/12.168570

KEYWORDS: Coronagraphy, Polarizers, Polarization, Mirrors, Magnetism, Solar processes, Multilayers, Reflectivity, Absorption, Optical filters

Read Abstract +

Proceedings Article | 1 February 1994 Paper

Performance of the repolished S-056 grazing incidence mirror in the MSFC AXAF test facility

Jonathan Campbell, Richard Hoover, Phillip Baker

Proceedings Volume 2011, (1994) https://doi.org/10.1117/12.167220

KEYWORDS: Mirrors, X-rays, Polishing, Surface finishing, Point spread functions, Space mirrors, X-ray telescopes, X-ray sources, Calibration, Surface roughness

Read Abstract +

Proceedings Article | 1 February 1994 Paper

X-ray/EUV/FUV calibration of photographic films for solar research

Richard Hoover, Arthur Walker, Craig DeForest, Maxwell Allen, David Gore

Proceedings Volume 2011, (1994) https://doi.org/10.1117/12.167232

KEYWORDS: Extreme ultraviolet, X-rays, Visible radiation, X-ray telescopes, Calibration, Telescopes, Spectroscopy, Photography, Multilayers, Spatial resolution

Read Abstract +

Proceedings Article | 1 February 1994 Paper

Astronomical observations with normal incidence multilayer optics III: selection of multilayer bandpasses

Arthur Walker, Lisa Jackson, James Plummer, Richard Hoover, Troy Barbee

Proceedings Volume 2011, (1994) https://doi.org/10.1117/12.167216

KEYWORDS: Multilayers, Telescopes, Iron, Mirrors, Solar processes, Extreme ultraviolet, Astronomy, Ions, Reflectivity, Reflection

Read Abstract +

Proceedings Article | 1 February 1994 Paper

MultiSpectral Solar Telescope Array VII: a status report

Arthur Walker, Richard Hoover, Troy Barbee

Proceedings Volume 2011, (1994) https://doi.org/10.1117/12.167218

KEYWORDS: Telescopes, Coronagraphy, Space telescopes, Iron, Solar processes, Image resolution, Multilayers, Spatial resolution, Sensors, Spectral resolution

Read Abstract +

Proceedings Article | 1 February 1994 Paper

Performance of the multilayer-coated mirrors for the MultiSpectral Solar Telescope Array

Maxwell Allen, Thomas Willis, Charles Kankelborg, Ray O'Neal, Dennis Martinez-Galarce, Craig DeForest, Lisa Jackson, James Plummer, Arthur Walker, Troy Barbee, J. Weed, Richard Hoover

Proceedings Volume 2011, (1994) https://doi.org/10.1117/12.167213

KEYWORDS: Telescopes, Mirrors, Reflectivity, Reflector telescopes, Space telescopes, Optical filters, Calibration, Aluminum, Monochromators, Silicon

Read Abstract +

Proceedings Article | 3 February 1993 Paper

Fabrication of grazing incidence optics using flow-polishing techniques

Phillip Baker, Richard Hoover, Arthur Walker

Proceedings Volume 1736, (1993) https://doi.org/10.1117/12.140475

KEYWORDS: Wavefronts, X-ray detectors, Physics, Monochromatic aberrations, Interferometry, Grazing incidence, Mirrors, Interferometers, Polishing, Bidirectional reflectance transmission function

Read Abstract +

Proceedings Article | 21 January 1993 Paper

Ultrahigh-resolution images of the solar chromosphere and corona using coordinated rocket and balloon observations

Arthur Walker, J. Gethyn Timothy, Richard Hoover, Troy Barbee

Proceedings Volume 1742, (1993) https://doi.org/10.1117/12.140586

KEYWORDS: Coronagraphy, Image resolution, Telescopes, Solar processes, Vacuum ultraviolet, Spectrographs, Spectral resolution, Magnetism, Spatial resolution, Iron

Read Abstract +

Proceedings Article | 21 January 1993 Paper

Multispectral solar telescope array: initial results and future plans

Arthur Walker, Richard Hoover, Troy Barbee

Proceedings Volume 1742, (1993) https://doi.org/10.1117/12.140583

KEYWORDS: Telescopes, Iron, Magnetism, Coronagraphy, Space telescopes, Image resolution, Solar processes, Spectral resolution, Mirrors, Spatial resolution

Read Abstract +

Proceedings Article | 21 January 1993 Paper

Polarimetry of HI Lyman-alpha for coronal magnetic field diagnostics

Silvano Fineschi, Richard Hoover, Muamer Zukic, Jongmin Kim, Arthur Walker, Phillip Baker

Proceedings Volume 1742, (1993) https://doi.org/10.1117/12.140576

KEYWORDS: Polarization, Magnetism, Coronagraphy, Scattering, Sun, Polarimetry, Polarizers, Diagnostics, Photons, Solar processes

Read Abstract +

Proceedings Article | 21 January 1993 Paper

Imaging Schwarzschild multilayer x-ray microscope

Richard Hoover, Phillip Baker, David Shealy, David Gore, Arthur Walker, Troy Barbee, Ted Kerstetter

Proceedings Volume 1742, (1993) https://doi.org/10.1117/12.140596

KEYWORDS: Microscopes, X-rays, X-ray imaging, Mirrors, Multilayers, X-ray telescopes, X-ray optics, Interferometry, Optical fabrication, Spatial resolution

Read Abstract +

Proceedings Article | 21 January 1993 Paper

Design and fabrication of the all-reflecting H-Lyman alpha coronagraph/polarimeter

Richard Hoover, R. Barry Johnson, Silvano Fineschi, Arthur Walker, Phillip Baker, Muamer Zukic, Jongmin Kim

Proceedings Volume 1742, (1993) https://doi.org/10.1117/12.140577

KEYWORDS: Coronagraphy, Polarizers, Polarization, Solar processes, Absorption, Telescopes, Magnetism, Image resolution, Mirrors, Optical filters

Read Abstract +

Proceedings Article | 21 January 1993 Paper

Calibration of the multispectral solar telescope array multilayer mirrors and XUV filters

Maxwell Allen, Thomas Willis, Charles Kankelborg, Ray O'Neal, Dennis Martinez-Galarce, Craig DeForest, Lisa Jackson, Joakim Lindblom, Arthur Walker, Troy Barbee, J. Weed, Richard Hoover, Forbes Powell

Proceedings Volume 1742, (1993) https://doi.org/10.1117/12.140588

KEYWORDS: Telescopes, Calibration, Aluminum, Reflectivity, Optical filters, Mirrors, Space telescopes, Tellurium, Multilayers, Reflector telescopes

Read Abstract +

Proceedings Article | 21 January 1993 Paper

Chromospheric and coronal observations with multilayer optics

Arthur Walker, Richard Hoover, Troy Barbee

Proceedings Volume 1742, (1993) https://doi.org/10.1117/12.140595

KEYWORDS: Multilayers, Extreme ultraviolet, Telescopes, Solar processes, Image resolution, Mirrors, Coronagraphy, X-rays, Reflection, Iron

Read Abstract +

Proceedings Article | 21 January 1993 Paper

Ultrahigh-resolution photographic films for x-ray/EUV/FUV astronomy

Richard Hoover, Arthur Walker, Craig DeForest, Richard Watts, Charles Tarrio

Proceedings Volume 1742, (1993) https://doi.org/10.1117/12.140587

KEYWORDS: Extreme ultraviolet, Photography, X-ray telescopes, Spatial resolution, X-rays, Spectroscopy, Coronagraphy, Image resolution, Sensors, Calibration

Read Abstract +

Proceedings Article | 13 January 1993 Paper

Design and analysis of a fast two-mirror soft x-ray microscope

David Shealy, Cheng Wang, Wu Jiang, L. Jin, Richard Hoover

Proceedings Volume 1741, (1993) https://doi.org/10.1117/12.138760

KEYWORDS: Microscopes, Mirrors, Head, Spherical lenses, Diffraction, Multilayers, X-ray microscopy, Monochromatic aberrations, X-rays, Optical design

Read Abstract +