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  • 1
    ISSN: 1432-072X
    Keywords: Anaerobic fungi ; Cellulase secretion ; Xylanase secretion ; Glucohydrolase ; Neocallimastix
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Four anaerobic fungi were grown on filter paper cellulose and monitored over a 7–8 days period for substrate utilisation, fermentation products, and secretion of cellulolytic and xylanolytic enzymes. Two of the fungi (N1 and N2) were Neocallimastix species isolated from a ruminant (sheep) and the other two fungi were Piromyces species (E2 and R1) isolated from an Indian Elephant and an Indian Rhinoceros, respectively. The tested anaerobic fungi degraded the filter paper cellulose almost completely and estimated cellulose digestion rates were 0.25, 0.13, 0.21 and 0.18 g · 1-1 · h-1 for strains E2, N1, N2, R1, respectively. All strains secreted cellulolytic and xylanolytic enzymes, including endoglucanase, exoglucanase, β-glucosidase and xylanase. Strain E2 secreted the highest levels of enzymes in a relatively short time. The product formation on avicel by enzymes secreted by the four fungi was studied. Both in the presence and absence of glucurono-1,5-δ-lactone, a specific inhibitor of β-glucosidase, mainly glucose was formed but no cellobiose. Therefore the exoglucanase secreted by the four fungi is probably a glucohydrolase.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-072X
    Keywords: Anaerobic fungi ; Methanogenic bacteria ; Coculture Neocallimastix ; Cellulase secretion ; Enzyme location
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Neocallimastix strain N1, an isolate from a ruminant (sheep), was cocultured with three Methanobacterium formicicum strains, Methanosarcina barkeri, and Methanobrevibacter smithii. The coculture with Methanobacterium formicicum strains resulted in the highest production of cellulolytic and xylanolytic enzymes. Subsequently four anaerobic fungi, two Neocallimastix strains (N1 and N2) from a ruminant and two Piromyces species from non-ruminants (E2 and R1), were grown in coculture with Methanobacterium formicicum DSM 3637 on filter paper cellulose and monitored over a 7-day period for substrate utilisation, fermentation products, and secretion of cellulolytic and xylanolytic enzymes. Methanogens caused a shift in fermentation products to more acetate and less ethanol, lactate and succinate. Furthermore the cellulose digestion rate increased by coculture. For cocultures of Neoallimastix strains with Methanobacterium formicicum strains the cellulolytic and xylanolytic enzyme production increased. Avicelase, CMCase and xylanase were almost completely secreted into the medium, while 40–60% of the β-glucosidase was found to be cell bound. Coculture had no significant effect on the location of cellulolytic and xylanolytic enzymes.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 111 (1976), S. 7-11 
    ISSN: 1432-072X
    Keywords: Bacillus subtilis ; Motility ; Chemotaxis ; Chemoreceptor ; Tumble generator ; Proton-motive force
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Changes in the proton-motive force cause a transient change in the motile behavior of Bacillus subtilis cells. Both an increase and a decrease in the proton-motive force cause transient tumbling. Simultaneous decrease of proton-motive force and increase of attractant concentration lessens the response toward the attractant. A simultaneous increase of proton-motive force and increase of attractant concentration prolonges the response toward attractant. A hypothesis explaining the various effects is given.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-072X
    Keywords: Ciliate culture ; Endosymbiosis ; Interspecies hydrogen transfer ; Hydrogenosome ; Methanogenic bacteria ; Methanoplanus endosymbiosus sp. nov. ; Metopus contortus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Epifluorescence microscopy revealed the presence of a methanogenic bacterium as an endosymbiont in the sapropelic marine ciliate Metopus contortus. The in situ methanogenic activity of the symbiont could be demonstrated. The isolated endosymbiont was an irregular, disc-shaped bacterium with a diameter of 1.6–3.4 μm. It had a generation time of 7 or 12 hours on growth on H2/CO2 or formate, respectively. The temperature range for growth was between 16 and 36°C with an optimum at 32°C. The optimal pH range for growth was 6.8 to 7.3. Salts, with an optimum concentration of 0.25 M, and tungsten were required for growth. The mol% G+C was 38.7%. The cell envelope consisted of proteins and a glycoprotein with an apparent molecular weight of 110,000. Morphology, antigenic relationship and the G+C content established the isolate MC1 as a new species of the genus Methanoplanus, and the name Methanoplanus endosymbiosus is proposed.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-072X
    Keywords: Key words:Methanobacterium thermoautotrophicum– Cyclic 2,3-diphosphoglycerate – 2,3-Diphosphoglycerate – Cyclic 2,3-diphosphoglycerate hydrolase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract. Cyclic 2,3-diphosphoglycerate (cDPG) hydrolase activity was demonstrated in cofactor-free extract of Methanobacterium thermoautotrophicum (strain ΔH), but not in crude extract. Only after ultrafiltration or dialysis of curde extract cDPG hydrolase activity could be shown. cDPG hydrolysis was optimal at pH 6.0 and 60 °C. Hydrolysis of cDPG occurred under nitrogen or hydrogen atmosphere and was completely inhibited by oxygen. Phosphate and potassium chloride were also strong inhibitors: 50% inhibition occurred at 0.6 – 0.7 mM phosphate or 0.2 M KCl. The enzyme was localized in the membrane fraction and could be solubilized for approximately 60% by treatment with 25 mM of the detergent CHAPS. The K m and the V max for cDPG were determined at 60 °C and were 59 mM and 216 mU/mg, respectively. Furthermore, cDPG hydrolase was dependent on the presence of Co2+. The role of cDPG and cDPG hydrolase is discussed.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 35 (1988), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . One of the two methanogenic endosymbionts of the giant sapropelic amoeba Pelomyxa palustris was isolated in pure culture. The cells were slender non-motile rods (3 × 0.4 μm), sometimes occurring in chains of 3–4 cells. Ultrathin sections revealed a Gram-positive cell wall and conically pointed ends with mesosome-like structures in the cytoplasm. The isolate had a generation time of 10 and 12 h during growth on H2/CO2 and formate, respectively. The optimum growth temperature was 40°C and the optimum pH was 7.8. The G+C content of its DNA was found to be 37.7% mole percent. The isolate was identified as Methanobacterium formicicum.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    World journal of microbiology and biotechnology 8 (1992), S. 428-433 
    ISSN: 1573-0972
    Keywords: Anaerobic digestion ; biogas ; cereal residues ; rumen micro-organisms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A recently developed high-rate, two-phase process, which employs rumen microorganisms for efficient acidogenesis, was tested for anaerobic degradation of barley straw, rye straw, and maize stover. Under conditions similar to those of the rumen and loading rates varying between 9.8 and 26.0 g of organic matter/I/day in the first phase (acidogenic reactor), total fibre degradation efficiencies ranged between 42% and 57%, irrespective of the loading rate applied. Average specific production of volatile fatty acids and biogas/g volatile solid digested in the acidogenic reactor varied between 6.9 and 11.2 mmol and 0.10 and 0.25 l, respectively. The effect of varying solid retention times on the extent of degradation of barley straw was examined. Changing of retention times in the range of 60 to 156 h had no effect on degradation efficiency, but a decrease in efficiency was observed at retention times below 60 h. By connecting the acidogenic reactor in series to an Upflow Anaerobic Sludge Blanket (UASB) methanogenic reactor the volatile fatty acids were converted into biogas. Average methane contents of the gases produced in the acidogenic reactor and in the UASB reactor were 30±3% and 78±3%, respectively.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Biotechnology letters 11 (1989), S. 61-66 
    ISSN: 1573-6776
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary The degradation of acetate, propionate and butyrate was monitored during start-up of five lab-scale methanogenic fluidized bed reactors on an artificially prepared waste water. The acetate concentration in the reactor content was found to influence the degradation of propionate but not of butyrate. In general, at acetate levels over 200 mg/l the degradation of propionate was below 60%, whereas the degradation was complete at acetate levels under 100 mg/l. The rationale of the inhibition of propionate degradation by acetate is discussed.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1617-4623
    Keywords: Key wordsAgaricus bisporus ; Glutamine synthetase ; Molecular cloning ; Gene structure ; Mushroom
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The gene encoding glutamine synthetase (glnA) was isolated from an Agaricus bisporus H39 recombinant λ phage library. The deduced A. bisporus glutamine synthetase amino acid sequence contains 354 residues. The amino acid sequence is very similar to that derived from the gene coding for glutamine synthetase of the yeast Saccharomyces cerevisiae. The open reading frame is interrupted by four introns. Northern analysis revealed that transcription of the gene is repressed upon addition of ammonium to the culture but the repression was not as strong as that of the gene encoding NADP+-dependent glutamate dehydrogenase (gdhA). Enzyme activities are low in the presence of ammonium, glutamine and albumin and do not correlate with the mRNA levels revealed by Northern analysis. This suggests that glutamine synthetase expression in A. bisporus is also post-transcriptionally regulated by the nitrogen source.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 25 (1969), S. 477-477 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Zusammenfassung Die Stereospezifität der Enzyme des Allantoinabbaus inStreptococcus allantoicus und die optische Drehung der Reaktionsprodukte wurde bestimmt. Allantoinase war aspezifisch, während Allantoate-amidohydrolase ausschliesslich (-)-Ureidoglykolate bildete. Diese Substanz wurde durch (-)-Ureidoglykolase hydrolysiert.
    Type of Medium: Electronic Resource
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