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  • 1
    Call number: AWI Bio-20-93990
    Description / Table of Contents: Assumed comparable environmental conditions of early Mars and early Earth in 3.7 Ga ago – at a time when first fossil records of life on Earth could be found – suggest the possibility of life emerging on both planets in parallel. As conditions changed, the hypothetical life on Mars either became extinct or was able to adapt and might still exist in biological niches. The controversial discussed detection of methane on Mars led to the assumption, that it must have a recent origin – either abiotic through active volcanism or chemical processes, or through biogenic production. Spatial and seasonal variations in the detected methane concentrations and correlations between the presence of water vapor and geological features such as subsurface hydrogen, which are occurring together with locally increased detected concentrations of methane, gave fuel to the hypothesis of a possible biological source of the methane on Mars. Therefore the phylogenetically old methanogenic archaea, which have evolved under early Earth conditions, are often used as model-organisms in astrobiological studies to investigate the potential of life to exist in possible extraterrestrial habitats on our neighboring planet. In this thesis methanogenic archaea originating from two extreme environments on Earth were investigated to test their ability to be active under simulated Mars analog conditions. These extreme environments – the Siberian permafrost-affected soil and the chemoautotrophically based terrestrial ecosystem of Movile cave, Romania – are regarded as analogs for possible Martian (subsurface) habitats. Two novel species of methanogenic archaea isolated from these environments were described within the frame of this thesis. It could be shown that concentrations up to 1 wt% of Mars regolith analogs added to the growth media had a positive influence on the methane production rates of the tested methanogenic archaea, whereas higher concentrations resulted in decreasing rates. Nevertheless it was possible for the organisms to metabolize when incubated on water-saturated soil matrixes made of Mars regolith analogs without any additional nutrients. Long-term desiccation resistance of more than 400 days was proven with reincubation and indirect counting of viable cells through a combined treatment with propidium monoazide (to inactivate DNA of destroyed cells) and quantitative PCR. Phyllosilicate rich regolith analogs seem to be the best soil mixtures for the tested methanogenic archaea to be active under Mars analog conditions. Furthermore, in a simulation chamber experiment the activity of the permafrost methanogen strain Methanosarcina soligelidi SMA-21 under Mars subsurface analog conditions could be proven. Through real-time wavelength modulation spectroscopy measurements the increase in the methane concentration at temperatures down to -5 °C could be detected. The results presented in this thesis contribute to the understanding of the activity potential of methanogenic archaea under Mars analog conditions and therefore provide insights to the possible habitability of present-day Mars (near) subsurface environments. Thus, it contributes also to the data interpretation of future life detection missions on that planet. For example the ExoMars mission of the European Space Agency (ESA) and Roscosmos which is planned to be launched in 2018 and is aiming to drill in the Martian subsurface
    Type of Medium: Dissertations
    Pages: VI, 108 Blätter , Illustrationen
    Language: English
    Note: Dissertation, Universität Potsdam, 2015 , Table of contents Preface Table of contents Summary Zusammenfassung 1. Introduction 1.1. Environmental conditions on past and present Mars 1.2. Detection of methane on Mars 1.3. Methanogenic archaea 1.4. Description of study sites 1.5. Aims and approaches 1.6. Overview of the publications 2. Publication I: Methanosarcina soligelidi sp. nov., a desiccationandfreeze-thaw-resistant methanogenic archaeon from a Siberianpermafrost-affected soil 3. Publication II: Methanobacterium movilense sp. nov.,ahydrogenotrophic, secondary-alcohol-utilizing methanogen fromthe anoxic sediment of a subsurface lake 4. Publication III: Influence of Martian Regolith Analogs on the activityand growth of methanogenic archaea,with special regard to long-term desiccation 5. Publication IV: Laser spectroscopic real time measurements ofmethanogenic activity under simulated Martian subsurface conditions 6. Synthesis and Conclusion 6.1. Synthesis 6.2. Conclusion and future perspectives 7. References 8. Acknowledgments
    Location: AWI Reading room
    Branch Library: AWI Library
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  • 2
    Unknown
    Dordrecht : Springer
    Keywords: Biochemical engineering ; Bioinformatics ; Microbial ecology ; Microbiology ; Mines and mineral resources
    ISBN: 9781402055898
    Language: English
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  • 3
    ISSN: 1432-072X
    Keywords: Key words:Thiobacillus intermedius–Thiobacillus versutus– Thiosulfate – Polythionates – Ion-pair chromatography – Microcalorimetry – Biofilm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. The growth of Thiobacillus (T.) intermedius strain K12 and Thiobacillus versutus strain DSM 582 on thiosulfate and tetrathionate was studied combining on-line measurements of metabolic activity and sulfur compound analysis. Most results indicate that T. intermedius oxidized thiosulfate via tetrathionate to sulfate. Concomittantly, sulfur compound intermediates like tri- and pentathionate were detectable. The formation is probably the result of highly reactive sulfane monosulfonic acids. The formation of tetrathionate allows the cells to buffer temporarily the proton excretion from sulfuric acid production. With T. versutus intermediate sulfur compounds were not detectable, however, sulfur was detectable. The possibility of a thiosulfate oxidation via dithionate, S2O |lefbop| 2− |clobop||opnbop| 6 |clobop| , is discussed. The on-line measurement of metabolic activity by microcalorimetry enabled us to detect that cells of T. intermedius adhere to surfaces and produce a biofilm by a metabolic process whereas those of T. versutus fail to do so. The importance of the finding is discussed.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-072X
    Keywords: Thiobacillus intermedius ; Thiobacillus versutus ; Thiosulfate ; Polythionates ; Ion-pair chromatography ; Microcalorimetry ; Biofilm
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The growth of Thiobacillus (T.) intermedius strain K12 and Thiobacillus versutus strain DSM 582 on thiosulfate and tetrathionate was studied combining on-line measurements of metabolic activity and sulfur compound analysis. Most results indicate that T. intermedius oxidized thiosulfate via tetrathionate to sulfate. Concomittantly, sulfur compound intermediates like triand pentathionate were detectable. The formation is probably the result of highly reactive sulfane monosulfonic acids. The formation of tetrathionate allows the cells to buffer temporarily the proton excretion from sulfuric acid production. With T. versutus intermediate sulfur compounds were not detectable, however, sulfur was detectable. The possibility of a thiosulfate oxidation via dithionate, S2O inf6 sup2- , is discussed. The on-line measurement of metabolic activity by microcalorimetry enabled us to detect that cells of T. intermedius adhere to surfaces and produce a biofilm by a metabolic process whereas those of T. versutus fail to do so. The importance of the finding is discussed.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A mixed culture of Thiobacillus ferrooxidans, T. thiooxidans, and Leptospirillum ferrooxidans was used for inoculation of a sulphidic ore body for a bacterial in-situ stope-leaching experiment in the Ilba mine in Romania. The ore body was inoculated with 107 cells/g ore. Measurements at six main sites of the ore body indicated that microbial leaching was started by the inoculation. After about 8 weeks, sufficient microbial activity was measurable only in the upper third of the ore body. Due to the angle of incidence of the ore (75°), the leach liquor percolated only through the upper part leaving two-thirds humidified unsatisfactorily. The leach results, metal mobilization, indicated that by inoculation with the indigenous microorganisms efficient leaching was achieved. Metal output after 18 months of operation amounted to 10% of Cu and 78% of Zn. In the winter months energy for aeration and circulation was not available and this was reflected by reduced values for microbial activity, temperature, and daily metal output. The biological metal mobilisation after 18 months of operation was as active as at the beginning. Cu was mobilised predominantly by microbial leaching whereas Zn was leached mainly by chemical reactions. Both mechanisms contributed equally to iron output.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1662-8985
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Acidithiobacillus ferrooxidans, an acidophilic, chemolithotrophic, γ-proteobacterium, isinvolved in the bioleaching of metal sulfides. For this process, bacterial attachment to mineralsurface and biofilm development play a pivotal role. Generally, biofilm formation and production ofexopolysaccharides is regulated by the second messenger cyclic diguanylic acid (c-di-GMP) whosecellular level depends on the synthesis and degradation activities of diguanylate cyclase (DGCs,with GGDEF domain) and phosphodiesterase (PDE, with EAL or HD-GYP domains), respectively.The analysis of the genomic sequence of A. ferrooxidans ATCC 23270 allowed us to identify 5putative orfs encoding DGC and/or PDE-like proteins. Four of them encode for bifunctionalputative proteins with GGDEF and EAL domains and are named AFE_0053, AFE_1360,AFE_1373 and AFE_1379. The fifth one named AFE_1852 has an EAL domain. The putativeproteins also include PAS and GAF domains involved in signal transduction. These features suggestan involvement in signalling transduction through the metabolism of c-di-GMP. The amino acidsequences of these putative proteins were aligned with known DGCs and PDEs. Alignmentsindicate that AFE_1360 and AFE_1373 share more consensus sequences with active PDEs, whereasAFE_0053 and AFE_1379 do with active DGCs. On the other hand, in AFE_1852 some conservedresidues of known active PDEs are changed. RT-PCR-experiments revealed that the genes thatencode for these putative DGCs and/or PDEs are expressed by growth on two different substrates.These preliminary results suggest that A. ferrooxidans possesses a c-di-GMP pathway that should beinvolved in biofilm formation, as it occurs in many bacteria
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Advanced materials research Vol. 20-21 (July 2007), p. 583-583 
    ISSN: 1662-8985
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The alpha-proteobacterial genus Acidiphilium consists of several acidophilic species,generally known as a part of the mesophilc microbial flora of leaching biotopes. All of them cangrow chemoorganotrophically on carbon sources like sugars and many express additionalphotosynthetic pigments. Thus far, only Ap. acidophilum is known to be capable ofchemolithotrophic growth on elemental sulfur oxidation. The oxidation potential of inorganic sulfurspecies by the other strictly heterotrophic species has not yet been thoroughly investigated. Here,we demonstrate the unequivocal evidence of inorganic sulfur compound oxidation by strains of Ap.cryptum and other Acidiphilium species. Evolutionary and biochemical aspects of this new featureamong the heterotrophic Acidiphilium spp. are discussed. This finding will possibly help to solvethe long-standing question about the biochemical nature of elemental sulfur oxidation in mesophilicleaching bacteria
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  • 8
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract The polar lipids of 5 species of Thiobacillus were extracted and purified. An analysis of the fatty acid composition of the polar lipids documented the presence of methoxy, cyclopropyl, monounsaturated and hydroxycyclopropyl fatty acids of sufficiently unusual structure to serve as ‘signatures’ for the presence of these organisms in environmental samples. The structures of the unusual fatty acids of the polar lipids were confirmed by mass spectrometry (MS) after isolation by capillary gas chromatography (GC).
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  • 9
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Microbial deterioration of materials - case histories and countermeasures: Checklist for recognition of microbial induced corrosion (MIC)
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1662-8985
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Leaching bacteria attach to their substrates, i.e. mineral sulfides, and form monolayeredbiofilms. In this study the biofilm formation of Acidithiobacillus ferrooxidans A2 on pyrite wasexamined using atomic force and epifluorescence microscopy (AFM and EFM, respectively). Anovel system by JPK instruments, the BioMaterial WorkstationTM, allows the investigation of thesame location on an opaque sample with AFM and EFM. Until recently this was only possible fortranslucent samples. Sessile bacteria on pyrite coupons were stained with 4’,6-diamidino-2-phenylindol (DAPI) and visualized by EFM as well as AFM. The best imaging conditions for AFMwere assessed. Scans of bacteria attached to pyrite were performed in contact mode in air as well asin tapping mode in fluid. Imaging in fluid was more challenging than imaging in air as bacteria tendto detach from their substratum. To avoid the dislocation of microorganisms by the AFM probe thesample was dried in air for 1 h prior to scanning in fluid. Scanning in air was performed with thewhole range of cantilever spring constants tested (k = 0.03 N/m to k = 0.65 N/m) while, forscanning in fluid, best results were achieved using stiffer cantilevers (k = 0.65 N/m)
    Type of Medium: Electronic Resource
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