Dr. Elena V. Pikuta Profile

Dr. Elena V. Pikuta

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Publications (31)

Proceedings Article | 21 September 2015 Paper

Search for the algorithm of genes distribution during the process of microbial evolution

Elena Pikuta

Proceedings Volume 9606, 96060Y (2015) https://doi.org/10.1117/12.2191197

KEYWORDS: Organisms, Bacteria, Biological research, Microorganisms, Databases, Genetics, Genetic algorithms, Mathematical modeling, Crystals, Proteins

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Previous two and three dimensional graph analysis of eco-physiological data of Archaea demonstrated specific geometry for distribution of major Prokaryotic groups in a hyperboloid function. The function of a two-sheet hyperboloid covered all known biological groups, and therefore, could be applied for the entire evolution of life on Earth. The vector of evolution was indicated from the point of hyper temperature, extreme acidity and low salinity to the point of low temperature and increased alkalinity and salinity. According to this vector, the following groups were chosen for the gene screening analysis. In the vector “High-Temperature → Low-Temperature” within extreme acidic pH (0-3), it is: 1) the hyperthermophilic Crenarchaeota – order Sulfolobales, 2) moderately thermophilic Euryarchaeota - Class Thermoplasmata, and 3) mesophilic acidophiles- genus Thiobacillus and others. In the vector “Low pH → High pH” the following groups were selected in three temperature ranges: a) Hyperthermophilic Archaea and Eubacteria, b) moderately thermophilic – representatives of the genera Anaerobacter and Anoxybacillus, and c) mesophilic haloalkaliphiles (Eubacteria and Archaea). The genes associated with acidophily (H⁺ pump), chemolitho-autotrophy (proteins of biochemichal cycles), polymerases, and histones were proposed for the first vector, and for the second vector the genes associated with halo-alkaliphily (Na⁺ pumps), enzymes of organotrophic metabolisms (sugar- and proteolytics), and others were indicated for the screening. Here, an introduction to the phylogenetic constant (ρ_η) is presented and discussed. This universal characteristic is calculated for two principally different life forms –Prokaryotes and Eukaryotes; Existence of the second type of living forms is impossible without the first one. The number of chromosomes in Prokaryotic organisms is limited to one (with very rare exceptions, to two), while in Eukaryotic organisms this number is larger. Currently, accumulation of data for genome sequences is in progress: about 3,500 draft sequences of genomes are available (of the total 12,000 species Bacteria and Archaea). The possibility of confirmation of the previously proposed mathematical model with an approach for genes screening in determined key groups of microorganisms in genomes databases is outlined and discussed in this article.

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

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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

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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

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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

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Proceedings Article | 26 September 2013 Paper

Evolution of life in three-dimensional modeling

Elena Pikuta, Adam Lewis, Ronald Merritt, Derek Newland, George Williams

Proceedings Volume 8865, 88650E (2013) https://doi.org/10.1117/12.2027034

KEYWORDS: 3D modeling, Mathematical modeling, Data modeling, Organisms, Visualization, Neodymium, Fungi, Bacteria, Mathematics, Ecology

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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

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Proceedings Article | 5 November 2012 Paper

Evolution of Archaea in 3D modeling

Elena Pikuta, Dragana Tankosic, Rob Sheldon

Proceedings Volume 8521, 85210H (2012) https://doi.org/10.1117/12.929945

KEYWORDS: 3D modeling, Ecosystems, Mathematical modeling, Microorganisms, Data modeling, Visualization, Systems modeling, Biological research, Analytical research, Organisms

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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

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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

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Proceedings Article | 23 September 2011 Paper

Overview of Archaea

Elena Pikuta

Proceedings Volume 8152, 81520N (2011) https://doi.org/10.1117/12.897082

KEYWORDS: Polymers, Electrons, Sulfur, Organisms, Oxygen, Bacteria, Hydrogen, Mode conditioning cables, Proteins, Iron

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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

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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

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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

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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

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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 | 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

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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 | 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

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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 | 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

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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

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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 | 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

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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

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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

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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

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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 | 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

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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 | 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

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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

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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

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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 | 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

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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 | 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

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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

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

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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.