Ruminococcus Albus
Mostrando 25-36 de 73 artigos, teses e dissertações.
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25. Pentose utilization by the ruminal bacterium Ruminococcus albus.
Ruminococcus albus is an important fibrolytic ruminal bacteria which degrades hemicellulose and ferments the resulting pentose sugars. However, little information is available on the utilization of pentoses by this organism or the effect of hexose sugars on pentose metabolism. Enzymatic studies indicated that R. albus metabolized pentoses via the pentose pho
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26. Degradation of barley straw, ryegrass, and alfalfa cell walls by Clostridium longisporum and Ruminococcus albus.
The recently isolated ruminal sporeforming cellulolytic anaerobe Clostridium longisporum B6405 was examined for its ability to degrade barley straw, nonlignified cell walls (mesophyll and epidermis) and lignified cell walls (fiber) of ryegrass, and alfalfa cell walls in comparison with strains of Ruminococcus albus. R. albus strains degraded 20 to 28% of the
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27. Characterization of a Cytoplasmic Reserve Glucan from Ruminococcus albus
Ruminococcus albus, an anaerobic bacterium that digests cellulose in the rumen of cattle, produces intracellular polysaccharide granules varying from 0.05 to 0.31 μm in diameter when grown in batch culture. This polysaccharide material was purified and found to contain d-glucose as the only reducing sugar. The polyglucose polymer was slightly opalescent in
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28. The use of 16S rRNA-targeted oligonucleotide probes to study competition between ruminal fibrolytic bacteria: pure-culture studies with cellulose and alkaline peroxide-treated wheat straw.
Specific oligonucleotide probes targeted to sites on the 16S rRNA of Ruminococcus albus 8, Ruminococcus flavefaciens FD-1, and Fibrobacter succinogenes S85 and a domain Bacteria probe were used to study bacterial interactions during the fermentation of cellulose and alkaline hydrogen peroxide-treated wheat straw in monocultures, dicultures, and tricultures.
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29. Intergeneric Protoplast Fusion between Ruminococcus albus and an Anaerobic Recombinant, FE7
Intergeneric protoplast fusion between Ruminococcus albus, a cellulolytic, gram-positive, anaerobic bacterium (Pcs Smr Kms), and an anaerobic recombinant, FE7 (Pcr Sms Kmr), having lignin-related compound-degrading activities, was performed under strictly anaerobic conditions to introduce cellulase genes into strain FE7. The fusion frequency varied with diff
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30. Fermentation of Insoluble Cellulose by Continuous Cultures of Ruminococcus albus
The hydrolysis and fermentation of insoluble cellulose (Avicel) by continuous cultures of Ruminococcus albus 7 was studied. An anaerobic continuous culture apparatus was designed which permitted gas collection, continuous feeding, and wasting at different retention times. The operation of the apparatus was controlled by a personal computer. Cellulose destruc
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31. Molecular beacons: trial of a fluorescence-based solution hybridization technique for ecological studies with ruminal bacteria.
Molecular beacons are fluorescent probes developed for solution rather than membrane hybridization. We have investigated the utility of these probes to study rumen microbial ecology. Two cellulolytic species, Ruminococcus albus and Fibrobacter succinogenes, were tested. Membrane and solution hybridizations gave similar results in competition experiments with
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32. Modification of the properties of a Ruminococcus albus endo-1,4-beta-glucanase by gene truncation.
An endo-1,4-beta-glucanase (EgI) gene isolated from Ruminococcus albus was deleted at the 5'-flanking region by gene truncation or at the 3'-flanking region by insertion of an omega (omega) fragment with a universal stop codon at the EcoRI or BamHI site. These modified genes were integrated into pUC vectors to construct chimera plasmids for Escherichia coli.
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33. Competition for cellulose among three predominant ruminal cellulolytic bacteria under substrate-excess and substrate-limited conditions.
Three predominant ruminal cellulolytic bacteria (Fibrobacter succinogenes S85, Ruminococcus flavefaciens FD-1, and Ruminococcus albus 7) were grown in different binary combinations to determine the outcome of competition in either cellulose-excess batch culture or in cellulose-limited continuous culture. Relative populations of each species were estimated by
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34. 3-Phenylpropanoic Acid Improves the Affinity of Ruminococcus albus for Cellulose in Continuous Culture
A continuous-culture device, adapted for use with solid substrates, was used to evaluate the effects of 3-phenylpropanoic acid (PPA) upon the ability of the South African strain Ruminococcus albus Ce63 to ferment cellulose. Steady states of fermentation were established with a dilution rate of 0.17 h−1, and the extent and volumetric rates of cellulose ferm
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35. Effect of 3-Phenylpropanoic Acid on Capsule and Cellulases of Ruminococcus albus 8
The morphology and cellulases of Ruminococcus albus 8 were markedly affected by the inclusion of 3-phenylpropanoic acid (PPA) in a defined growth medium. PPA-grown bacteria produced substantial quantities of cell-bound cellulase, as well as a very high-molecular-weight extracellular enzyme and lesser amounts of two low-molecular-weight enzymes. PPA-deprived
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36. Kinetics of Insoluble Cellulose Fermentation by Continuous Cultures of Ruminococcus albus
Data from analyses of continuous culture fermentation of insoluble cellulose by Ruminococcus albus 7 were used to derive constants for the rate of cellulose hydrolysis and fermentation, growth yield, and maintenance. Cellulose concentration was 1% in the nutrient reservoir, and hydraulic retention times of 0.5, 1.0, 1.5, 1.75, and 2.0 days were used. Concent