Stoichiometry of glucose and starch splitting by strains of amylolytic bacteria from the rumen and anaerobic digester

The stoichiometry of glucose and starch splitting by the amylolytic bacteria Streptococcus bovis, Selenomonas ruminantium, Butyrivibrio fibrisolvens, Eubacterium ruminantium and Clostridium sp. was followed. There were many differences in the ratios of metabolites and in growth yields, as well as in the cell composition, between the growth on glucose and starch. The bacteria employ different nutritional strategies with respect to both energy sources.     

A highly active extracellular cellulase from the anaerobic rumen fungus Neocallimastix frontalis

Abstract An extracellular cellulase which was highly active in solubilizing the highly hydrogen bond-ordered cellulose in cotton fibre was found in a culture filtrate of the anaerobic fungus, Neocallimastix frontalis , isolated from the rumen of a sheep. The cellulase was several-fold more active in solubilizing cotton fibre per unit of endo-1,4-β-glucanase than the cellulase of the aerobic fungus Trichoderma reesei mutant strain C-30, which is one of the most active cellulases isolated so far.     

Stoichiometry of glucose and starch splitting by strains of amylolytic bacteria from the rumen and anaerobic digester

The stoichiometry of glucose and starch splitting by the amylolytic bacteria Streptococcus bovis, Selenomonas ruminantium, Butyrivibrio fibrisolvens, Eubacterium ruminantium and Clostridium sp. was followed. There were many differences in the ratios of metabolites and in growth yields, as well as in the cell composition, between the growth on glucose and starch. The bacteria employ different nutritional strategies with respect to both energy sources.     

Effect of pH on growth rates of rumen amylolytic and lactilytic bacteria.

The relationship between the pH of the medium and specific growth rates, in well-buffered media at 38.5 degrees C, was determined for three strains of Butyrivibrio fibrisolvens and for one strain each of Streptococcus bovis, Selenomonas ruminantium subsp. lactilytica. Megasphaera elsdenii, Veillonella alcalescens, and Propionibacterium acnes. The pH optima for growth were between 6.1 and 6.6 for all six species, and the upper pH limits were between 7.3 and 7.8. The lower limit pH values for growth on glucose were 5.4 for B. fibrisolvens, near 5.0 for V. alcalescens, and between 4.4 and 4.8 for the other four species. These values fall within the minimum pH ranges found when these species are grown in poorly buffered medium with nonlimiting glucose concentrations. Acid sensitivity per se could cause the washout of B. fibrisolvens, but not of the other five species, from the rumens of animals on high-starch diets.     

Purification and characterization of an active N-acetylglucosaminyltransferase enzyme complex from Streptococci

A new family of bacterial serine-rich repeat glycoproteins can function as adhesins required for biofilm formation and pathogenesis in streptococci and staphylococci. Biogenesis of these proteins depends on a gene cluster coding for glycosyltransferases and accessory secretion proteins. Previous studies show that Fap1, a member of this family from Streptococcus parasanguinis, can be glycosylated by a protein glycosylation complex in a recombinant heterogeneous host. Here we report a tandem affinity purification (TAP) approach used to isolate and study protein complexes from native streptococci. This method demonstrated that a putative glycosyltransferase (Gtf2), which is essential for Fap1 glycosylation, readily copurified with another glycosyltransferase (Gtf1) from native S. parasanguinis. This result and the similar isolation of a homologous two-protein complex from Streptococcus pneumoniae indicate the biological relevance of the complexes to the glycosylation in streptococci. Furthermore, novel N-acetylglucosaminyltransferase activity was discovered for the complexes. Optimal activity required heterodimer formation and appears to represent a novel type of glycosylation.     

A study of the role of histidine side-chains at the active centre of amylolytic enzymes

The role of histidine side-chains in reactions catalysed by porcine-pancreatic alpha-amylase, sweet-potato beta-amylase, and Aspergillus niger glucamylase has been studied by using diethyl pyrocarbonate, a specific protein reagent. Changes in the activity, binding affinity, and apparent kinetic parameters due to ethoxycarbonylation have been determined. For pancreas alpha-amylase, four of the eight histidine groups, for sweet-potato beta-amylase, six of the seven histidine groups, and for A. niger glucamylase, four of the six histidine groups were shown to be ethoxycarbonylated. Ethoxycarbonylation occurred as an apparent first-order reaction, with rate constants in the range 3.6–4.9 x 10^?2min^?1. Ethoxycarbonylation of the histidine group at the active centre rapidly inactivated alpha-amylase, whereas the other three groups are not located in the active centre, although activity and substrate binding are only slightly affected by their modification. For beta-amylase and glucamylase, only slight or no change in activity could be detected on ethoxycarbonylation, whereas significant changes were observed in the binding affinity.     

The intracellular polysaccharide of the rumen bacterium Eadie's Oval

Summary The intracellular storage polysaccharide of the rumen organism Eadie's Oval has been purified and found to be a glucan of the glycogen type consisting solely of -1,4- and -1,6-linked glucose units. It is highly branched with mean exterior and interior chain lengths of 7 and 3 respectively, polydisperse with a mean molecular weight of approximately 4.3×10⁶.     

Isolation of a serologically different compact-colony-forming active substance from strains of Staphylococcus aureus

To observe the possible serological heterogeneity of compact-colony-forming active substance (CCFAS), heat-killed vaccines were prepared by two strains of Staphylococcus aureus, strains SMU 1-46 and SMU 7931, cultured in 0.03 M trishydrochloride-buffered brain heart infusion, pH 8.4. After immunization with the vaccine in rabbits, antibody responses were observed during a period of six weeks after the immunization either by homologous and heterologous organisms using alkaline serum-soft agar technique. The results showed that remarkable antibody production was shown only against homologous strain, but not against heterologous strain. The antibodies were absorbed out only with highly purified preparation of CCFAS extracted from homologous strain and not with heterologous CCFAS. Differences of the major chemical composition of the substances showed that highly purified CCFAS extracted from strain SMU 7931 contained 2.84 and 2.04 times higher amounts of galactose and 2-amino-2-deoxy-D-galacturonic acid than those of CCFAS obtained from strain SMU 1-46.