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  • 1
    Electronic Resource
    Electronic Resource
    Heterologous expression of the Bacteroides ruminicola xylanase gene in Bacteroides fragilis and Bacteroides uniformis (1990)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 66 (1990), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract A cloned xylanase gene from the ruminal bacterium Bacteroides ruminicola 23 was transferred by conjugation into the colonic species Bacteroides fragilis and Bacteroides uniformis by using the Escherichia coli-Bacteroides shuttle vector pVAL-1. The cloned gene was expressed in both species, and xynalase specific activity in crude extracts was found to be at least 1400-fold greater than that found in the B. ruminicola strain. Analysis of crude extract proteins from the recombinant B. fragilis by SDS-PAGE demonstrated a new 60 000 molecular weight protein. The xynalase activity expressed in both E. coli and B. fragilis was capable of degrading xylan to xylooligosaccharides in vitro. This is the first demonstration that colonic Bacteroides species can express a gene from a ruminal Bacteroides species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1990.tb03973.x
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  • 2
    Electronic Resource
    Electronic Resource
    Changes in cell composition and viability of Bdellovibrio bacteriovorus during starvation (1974)
    Springer
    Archives of microbiology 97 (1974), S. 313-327 
    Details
    ISSN: 1432-072X
    Keywords: Bdellovibrio bacteriovorus ; Starvation Effects ; Viability Loss ; Cell Material Loss ; Endogenous Respiration ; Bacterial Parasitism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 1. Washed cell suspensions of Bdellovibrio bacteriovorus harvested shortly after lysis of their substrate organisms and shaken in buffer have a constant and high endogenous respiration rate for a bout 6 h which then declines sharply to a rate approximately 10% of the original. Viability of cell suspensions shows little change over the first 4–6 h and then decreases by some 50% in 10 h. 2. Over the first 5–6 h of starvation there is a loss of about 50% of total cell carbon. This loss is distributed about equally between CO2 and small molecules released into the suspending buffer. The protein and nucleic acid contents of the cells decrease concomitantly from time zero during starvation while DNA content remains constant. Ribosomal profiles show a rapid degradation of ribosomes. 3. In the presence of glutamate or glutamate plus a balanced amino acid mixture, loss of cell material and loss of viability is partially or completely prevented. There is extensive protein turnover when glutamate and an amino acid mixture are available to the bdellovibrio. 4. The pattern of changes observed in B. bacteriovorus during starvation is compared to reported changes in other species of bacteria, and the significances of its high endogenous respiration and sensitivity to starvation are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00403070
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  • 3
    Electronic Resource
    Electronic Resource
    Amino acid and glucose fermentation by Treponema denticola (1971)
    Springer
    Archives of microbiology 78 (1971), S. 234-251 
    Details
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Treponema denticola was grown in serum-containing media to which 14C-labelled compounds were added. Determinations of radioactivity in the products formed indicated that the organism fermented alanine, cysteine, glycine, serine, and glucose. Fermentation products included acetate, lactate, succinate, formate, pyruvate, ethanol, CO2, H2S, and NH3. The products formed from glucose constituted a small portion of the total products. Assays of enzymatic activities in cell extracts indicated that the organism degraded glucose via the Embden-Meyerhof pathway. T. denticola possessed a coenzyme A-dependent CO2-pyruvate exchange activity associated with a clostridial-type clastic system for pyruvate metabolism. Phosphotransacetylase and acetate kinase activities were present in cell extracts. Acetyl phosphate formation and benzyl viologen reduction were detected when cell extracts were incubated with pyruvate, serine or cysteine. The data indicate that T. denticola is an amino acid fermenter and that it possesses the enzymes needed for the fermentation of glucose. However, glucose does not serve as the primary substrate when the organism grows in media including both this carbohydrate and amino acids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00424897
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  • 4
    Electronic Resource
    Electronic Resource
    Attempts to grow bdellovibrios micurgically-injected into animal cells (1978)
    Springer
    Archives of microbiology 119 (1978), S. 245-248 
    Details
    ISSN: 1432-072X
    Keywords: Bdellovibrio ; Micurgy ; Rabbit ova ; Mammalian ova ; Intracellular growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Incubation in buffer of Bdellovibrio bacteriovorus 109J, B. stolpii UKi2, or B. starrii A3.12 with washed eucaryotic animal cells (mouse liver, hamster kidney, or bovine mammary gland) resulted in neither attachment nor growth of the bdellovibrios. When cells of these bdellovibrio strains were incubated with erythrocyte suspensions (bovine or rabbit) a very low level of bdellovibrio attachment and penetration occurred, but no growth could be detected. Using micurgical procedures, bdellovibrios were injected into the perivetelline space or the cytoplasm of rabbit ova. After 18–24h incubation, neither a significant loss nor increase of injected, intracellular bdellovibrios was observed. Limited axenic growth of bdellovibrios (109J or UKi2) occurred in media containing rabbit ova extracts and dilute nutrient broth. It is concluded that eucaryotic rabbit ova do not provide a suitable environment for intracellular bdellovibrio growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00405402
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  • 5
    Electronic Resource
    Electronic Resource
    Spirochaeta litoralis sp. n., a strictly anaerobic marine spirochete (1970)
    Springer
    Archives of microbiology 74 (1970), S. 1-18 
    Details
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A strictly anaerobic spirochete was isolated from a sample of marine mud. The organism possessed two axial fibrils entwined with the regularly coiled protoplasmic cylinder. An outer envelope or sheath enclosed both protoplasmic cylinder and axial fibrils. The spirochete grew in chemically defined media containing glucose, amino acids or NH4Cl, sulfide, NaCl, vitamins, coenzyme A, and in-organic salts. A reducing agent, such as sodium sulfide or l-cysteine, as well as exogenous supplements of biotin, niacin and coenzyme A were required for growth. Pantothenate replaced coenzyme A as an exogenous growth factor, but the resulting cell yields were low. The spirochete grew in media prepared with sea water, but not in fresh water media containing less than 0.05 M NaCl (optimum concentration 0.35 M). Both Na+ and Cl- were required. Carbohydrates served as fermentable substrates. Amino acids, sugar alcohols, tricarboxylic acid cycle intermediates, and other organic acids and alcohols were not fermented. Glucose was fermented to ethyl alcohol, acetate, CO2, H2, and small amounts of lactate, formate and pyruvate. The guanine + cytosine content of the DNA of the spirochete was 50.5 moles-% (buoyant density). It is proposed that the marine isolate be considered a new species and that it be named Spirochaeta litoralis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00408683
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  • 6
    Electronic Resource
    Electronic Resource
    Ethanol production from AFEX pretreated corn fiber by recombinant bacteria (1996)
    Springer
    Biotechnology letters 18 (1996), S. 985-990 
    Details
    ISSN: 1573-6776
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary Fermentation of an enzymatic hydrolyzate of ammonia fiber explosion (AFEX) pretreated corn fiber (containing a mixture of different sugars including glucose, xylose, arabinose, and galactose) by genetically-engineered Escherichia coli strain SL40 and KO11 and Klebsiella oxytoca strain P2 was investigated under pH-controlled conditions. Both E. coli strains (SL40 and KO11) efficiently utilized most of the sugars contained in the hydrolyzate and produced a maximum of 26.6 and 27.1 g/l ethanol, respectively, equivalent to 90 and 92% of the theoretical yield. Very little difference was observed in cell growth and ethanol production between fermentations of the enzymatic hydrolyzate and mixtures of pure sugars, simulating the hydrolyzate. These results confirm the fermentability of the AFEX-treated corn fiber hydrolyzate by ethanologenic E. coli. K.oxytoca strain P2, on the other hand, showed comparatively poor growth and ethanol production (maximum 20 g/l) from both enzymatic hydrolyzate and simulated sugar mixtures under the same fermentation conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00154635
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  • 7
    Electronic Resource
    Electronic Resource
    Xylanolytic activities ofSpirochaeta thermophila (1994)
    Springer
    Current microbiology 29 (1994), S. 343-347 
    Details
    ISSN: 1432-0991
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Spirochetes capable of degrading xylan or cellulose have not been commonly isolated, nor have their polysaccharolytic activities been characterized.Spirochaeta thermophila strain RI 19.B1 is xylanolytic and grows well at 65°C with oatspelt (OX), birchwood (BX), corncob (CCX-A) xylans, or glucuronoxylan (MGX) as the energy source. All xylans were extensively degraded and utilized during growth. About 72–82% of the initial hexuronic acids and 57–79% of initial pentoses disappeared during growth.S. thermophila possessed xylanase, xylosidase, and arabinofuranosidase enzyme activities. Low levels of these activities were detected with growth on glucose, but high expression of these activities occurred during growth on OX. All three activities were cell-associated and were more stable in cells than cell extracts. Xylan-degrading activities were measured with cells or cell extracts exposed (60 min) to a variety of temperatures (65°–85°C) and pHs (5.0–8.0). More than 50% loss of activities occurred at temperatures above 75°C. Although pH stability was affected by buffer, the optimal range was pH 6.5–7.5. These temperature and pH profiles for xylan-degrading activities coincide with those found for the growth ofS. thermophila.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01570227
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  • 8
    Electronic Resource
    Electronic Resource
    Fermentation of xylans byButyrivibrio fibrisolvens andThermoanaerobacter strain B6A: Utilization of uronic acids and xylanolytic activites (1992)
    Springer
    Current microbiology 25 (1992), S. 189-195 
    Details
    ISSN: 1432-0991
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Butyrivibrio fibrisolvens andThermoanaerobacter strain B6A are xylanolytic anaerobes isolated from rumen and geothermal sources respectively. Both organisms fermented larchwood xylan, oatspelt xylan, or 4-O-methylglucuronoaxylan, extensively utilizing both the monosaccharide (glucose, xylose, arabinose) and uronic acid components. Citrus pectin or polygalacturonate also supported growth of both organisms, but onlyB. fibrisolvens was able to use the monomers glucuronate or galacturonate as the sole added energy source. Strain B6A was able to utilize these two uronic acids when glucose, xylose, arabinose, or oatspelt xylan was also provided as a second energy source. Xylanase, xylosidase, and arabinofuranosidase activities were found to be produced by strain B6A, but the levels and distribution (cell bound vs. culture fluid) were influenced by growth substrate. The highest levels were observed with growth on xylans when xylanase activity was mainly extracellular, but the other two activities were mostly cell bound. Apparently,Thermoanaerobacter strain B6A, but notB. fibrisolvens, requires xylan degradation products generated by these three activities to provide energy sources to utilize the uronic acid components on xylans.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01570718
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  • 9
    Electronic Resource
    Electronic Resource
    Survival ofMegasphaera elsdenii during starvation (1981)
    Springer
    Current microbiology 5 (1981), S. 51-56 
    Details
    ISSN: 1432-0991
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Batch- and continuous-cultured cell suspensions of the anaerobic ruminal bacteriumMegasphaera elsdenii strain T-81 were subjected to total nutrient starvation, during which time changes in cell viability, cell composition, and endogenous fermentation acids were monitored. The populations exhibited poor survival capabilities with a 50% survival time of 9–13 h. The primary substrates used for endogenous metabolism appeared to be cellular RNA, carbohydrate, and possibly protein. The types and amounts of major fermentation acids (acetic, butyric, caproic) released from starving cells varied depending upon initial growth conditions and starvation time. The data suggest that growth conditions affect cell composition and have important roles in survival ofM. elsdenii.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01566598
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  • 10
    Electronic Resource
    Electronic Resource
    Phylogenetic relationships among various helical bacteria (1982)
    Springer
    Current microbiology 7 (1982), S. 119-124 
    Details
    ISSN: 1432-0991
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Helical bacteria from the generaSpirillum, Oceanospirillum, Aquaspirillum, andAzospirillum—as well asSerpens flexibilis—were characterized by oligonucleotide cataloging of 16S rRNA in order to establish their phylogenetic relationships to one another and to Gramnegative bacteria in general. The various genera of helical bacteria are not specifically related to one another (to the exclusion of nonhelical bacteria) and, where tested, the individual genera as presently constituted are not phylogenetically coherent (with the possible exception ofOceanospirillum, which may form a deep grouping).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01568426
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