Comparison of Substrate Affinities Among Several Rumen Bacteria: a Possible Determinant of Rumen Bacterial Competition
AUTOR(ES)
Russell, James B.
RESUMO
Five rumen bacteria, Selenomonas ruminantium, Bacteroides ruminicola, Megasphaera elsdenii, Streptococcus bovis, and Butyrivibrio fibrisolvens were grown in continuous culture. Estimates of substrate affinities were derived from Lineweaver-Burk plots of dilution rate versus substrate concentration. Each bacterium was grown on at least four of the six substrates: glucose, maltose, sucrose, cellobiose, xylose, and lactate. Wide variations in substrate affinities were seen among the substrates utilized by a species and among species for the same substrate. These wide differences indicate that substrate affinity may be a significant determinant of bacterial competition in the rumen where soluble substrate concentrations are often low. Growth of these bacteria in continuous culture did not always follow typical Michaelis-Menten kinetics. Inflated theoretical maximum growth rates and non-linear Lineweaver-Burk plots were sometimes seen. Maintenance energy expenditures and limitation of growth rate by factors other than substrate concentration (i.e., protein synthesis) are discussed as possible determinants of these deviations.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=243250Documentos Relacionados
- Substrate Preferences in Rumen Bacteria: Evidence of Catabolite Regulatory Mechanisms
- Comparison of Maintenance Energy Expenditures and Growth Yields Among Several Rumen Bacteria Grown on Continuous Culture
- Competition for cellulose among three predominant ruminal cellulolytic bacteria under substrate-excess and substrate-limited conditions.
- Competition for cellobiose among three predominant ruminal cellulolytic bacteria under substrate-excess and substrate-limited conditions.
- Vitamin Requirements of Several Cellulolytic Rumen Bacteria1