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  • 1
    Electronic Resource
    Electronic Resource
    Effect of culture conditions on the production of an extracellular proteinase by Thermus sp. Rt41A (1994)
    Springer
    Applied microbiology and biotechnology 41 (1994), S. 400-406 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Thermus sp. Rt41A produced a single extracellular proteinase, as determined by fast protein liquid chromatography and isoelectric focusing. Proteinase activity was expressed from very early in the log phase, and halted when the growth substrate was exhausted. There was no continued proteinase production in the stationary phase. Proteinase production was not stimulated by O2 limitation, not repressed by amino acid growth substrates, and its production could not be correlated to the type or oxidation state of the carbon and energy source or the growth rate on different carbon and energy sources. Growth on certain substrates, e.g. glutamate and glucose, resulted in production of high levels of proteinase, whereas others, such as acetate, resulted in low proteinase levels. Acetate repressed proteinase production in cultures growing on L-glutamate. In continuous culture on L-glutamate, acetate or pyruvate, proteinase production was highest at higher growth (dilution) rates. The kinetics of proteinase production in continuous culture on L-glutamate can be interpreted as evidence for the constitutive nature of proteinase expression by Thermus sp. Rt41A. The data obtained show that the control of proteinase production is different to that postulated for Thermus sp. Ok6.A1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01982527
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  • 2
    Electronic Resource
    Electronic Resource
    Succinate decarboxylation by Propionigenium maris sp. nov., a new anaerobic bacterium from an estuarine sediment (1995)
    Springer
    Archives of microbiology 164 (1995), S. 29-35 
    Details
    ISSN: 1432-072X
    Keywords: Key wordsPropionigenium maris sp. nov. ; Anaerobic degradation ; Succinate ; Propionate ; Decarboxylation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Enrichments on succinate plus yeast extract under anoxic conditions from intertidal mud-flat sediments yielded cultures dominated by oval to round-ended rod-shaped cells. Strain 10succ1, obtained in pure culture, was characterized in detail. The non-motile cells possessed a gram-negative cell wall and did not form spores. Carbohydrates were fermented to formate, acetate, ethanol, and lactate. Succinate was decarboxylated to propionate. Other organic and amino acids were variously fermented to formate, acetate, propionate, and butyrate. Sulfur, sulfate, thiosulfate, and nitrate were not used as electron acceptors. Growth required the presence of yeast extract and at least 5 g/l NaCl, and was possible only in the absence of oxygen. No cytochromes were detected. The DNA base ratio was 40 mol% G+C. Phylogenetically, strain 10succ1 is closely related to Propionigenium modestum, as revealed by 16S rDNA analysis, but is physiologically distinct. Accordingly, strain 10succ1 (DSM 9537) is described as the type strain of a new species of the genus Propionigenium, P. maris sp. nov.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002030050232
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  • 3
    Electronic Resource
    Electronic Resource
    Disproportionation of inorganic sulfur compounds by the sulfate-reducing bacterium Desulfocapsa thiozymogenes gen. nov., sp. nov. (1996)
    Springer
    Archives of microbiology 166 (1996), S. 184-192 
    Details
    ISSN: 1432-072X
    Keywords: Key words Sulfur ; Thiosulfate ; Sulfite ; Disproportionation (thiosulfate ; sulfite) ; Sulfate ; reduction ; Ferric iron ; Desulfocapsa thiozymogenes ; Desulfobulbus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new strictly anaerobic, gram-negative bacterium was isolated from the sediment of a freshwater lake after enrichment with thiosulfate as the energy source. The strain, named Bra2 (DSM 7269), is able to grow by disproportionation of thiosulfate or sulfite to sulfate plus sulfide. Elemental sulfur is also disproportionated to sulfate and sulfide, but this only supports growth if free sulfide is chemically removed from the culture, e.g., by precipitation with amorphous ferric hydroxide. Growth is also possible by coupling the reduction of sulfate to sulfide with the oxidation of ethanol, propanol, or butanol to the corresponding fatty acid. The cells are rod-shaped, motile, and have genomic DNA with a mol% G+C content of 50.7. Cytochromes are present, but desulfoviridin is not. The new strain was shown to be related to, but distinct from members of the genus Desulfobulbus on the basis of physiological characteristics and by comparative sequence analysis of its 16S rDNA. Strain Bra2 is described as the type strain of a new taxon, Desulfocapsa thiozymogenes gen. nov., sp. nov.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002030050374
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  • 4
    Electronic Resource
    Electronic Resource
    Metabolic pathways and energetics of the acetone-oxidizing, sulfate-reducing bacterium, Desulfobacterium cetonicum (1995)
    Springer
    Archives of microbiology 163 (1995), S. 188-194 
    Details
    ISSN: 1432-072X
    Keywords: Key words Anaerobic degradation ; Acetone ; Carboxylation ; Energetics ; Sulfate-reducing bacterium ; Desulfobacterium cetonicum ; Citric acid cycle ; Glyoxylate cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Acetone degradation by cell suspensions of Desulfobacterium cetonicum was CO2-dependent, indicating initiation by a carboxylation reaction. Degradation of butyrate was not CO2-dependent, and acetate accumulated at a ratio of 1 mol acetate per mol butyrate degraded. In cultures grown on acetone, no CoA transfer apparently occurred, and no acetate accumulated in the medium. No CoA-ligase activities were detected in cell-free crude extracts. This suggested that the carboxylation of acetone to acetoacetate, and its activation to acetoacetyl-CoA may occur without the formation of free acetoacetate. Acetoacetyl-CoA was thiolytically cleaved to two acetyl-CoA, which were oxidized to CO2 via the acetyl-CoA/carbon monoxide dehydrogenase pathway. The measured intracellular acyl-CoA ester concentrations allowed the calculation of the free energy changes involved in the conversion of acetone to acetyl-CoA. At in vivo concentrations of reactants and products, the initial steps (carboxylation and activation) must be energy-driven, either by direct coupling to ATP, or coupling to transmembrane gradients. The ΔG' of acetone conversion to two acetyl-CoA at the expense of the energetic equivalent of one ATP was calculated to lie very close to 0 kJ (mol acetone)–1. Assimilatory metabolism was by an incomplete citric acid cycle, lacking an activity oxidatively decarboxylating 2-oxoglutarate. The low specific activities of this cycle suggested its probable function in anabolic metabolism. Succinate and glyoxylate were formed from isocitrate by isocitrate lyase. Glyoxylate thus formed was condensed with acetyl-CoA to form malate, functioning as an anaplerotic sequence. A glyoxylate cycle thus operates in this strictly anaerobic bacterium. Phosphoenolpyruvate (PEP) carboxykinase formed PEP from oxaloacetate. No pyruvate kinase activity was detected. PEP presumably served as a precursor for polyglucose formation and other biosyntheses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00305352
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  • 5
    Electronic Resource
    Electronic Resource
    Clostridium viride sp. nov., a strictly anaerobic bacterium using 5-aminovalerate as growth substrate, previously assigned to Clostridium aminovalericum (1994)
    Springer
    Archives of microbiology 162 (1994), S. 387-394 
    Details
    ISSN: 1432-072X
    Keywords: Key words     Clostridium viride sp. nov. ; Clostridium aminovalericum ; 5-Aminovalerate ; Sulphur reduction ; Anaerobic degradation ; 2 ; 4-Pentadienoyl-CoA reductase ; 5-Hydroxyvaleryl-CoA dehydratase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract      Strain T2–7, a 5-aminovalerate-fermenting bacterium previously classified as Clostridium aminovalericum, was further characterized, both physiologically and phylogenetically. Comparative sequencing analysis of the almost complete 16S rDNA revealed that strain T2–7 forms a distinct lineage within a phylogenetically coherent cluster of gram-positive bacteria currently assigned to the genus Clostridium. Strain T2–7 grew with 5-aminovalerate, 5-hydroxyvalerate, 4-hydroxybutyrate, vinylacetate, and crotonate, and required yeast extract and l-cysteine for growth. Other substrates were not utilized. The fermentation products, depending on the growth substrate, were ammonia, acetate, propionate, butyrate, and valerate. Sulphur was reduced by a mechanism not linked to energy conservation. Other acceptors were not utilized. Cells were gram-positive pointed-ended ovals, motile by means of two subpolar flagella, and possessed a gram-positive cell wall structure with an S-layer of hexagonally arranged subunits of 18.5 nm diameter. The DNA mol% G+C was 41.5. Strain T2–7 (DSM 6836) is proposed as the type strain of a new species, Clostridium viride sp. nov.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002030050155
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  • 6
    Electronic Resource
    Electronic Resource
    The uncertainty in forecasting trends of forest soil acidification (1993)
    Springer
    Water, air & soil pollution 66 (1993), S. 29-58 
    Details
    ISSN: 1573-2932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A Regional Soil Acidification Model (RESAM) has been developed to gain insight in long-term impacts of deposition scenarios on forest soils in The Netherlands. Model predictions of such large-scale environmental effects of acid deposition require extrapolation of site specific data to large geographical regions. The major aim of this study is to quantify the uncertainty in model response to a given deposition scenario, due to uncertainty and spatial variability in data. Furthermore, the uncertainty analysis was performed to determine which additional data will most likely improve the reliability of predictions. An efficient Monte Carlo technique was used in combination with regression analysis. The analysis was restricted to one forest soil ecosystem: a leptic podzol with Douglas fir, subject to a reducing deposition scenario. The investigated output variables were pH, Al/Ca ratio and NH4/K ratio in the root zone, which are generally used as indicators of forest soil acidification and of potential forest damage. Statistical analyses showed that in most cases the relation between the parameters and model output can be satisfactorily described by a linear regression model. The uncertainty contribution of various parameters depends on the considered output variable, soil compartment and time. The uncertainty, as measured by the coefficient of variation, appears to be high for the NH4/K and Al/Ca ratios, whereas it was relatively low for the pH. Results show that the uncertainty in the depositions of SOx, NOx, and NHx in a receptor area and the uncertainty in the parameters and variables determining the nitrogen and aluminium dynamics contribute most to the resulting uncertainty of the considered model output.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00477059
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