Metabolism of Peptides by Rumen Microorganisms

Wright, D. E.

doi:10.1128/aem.15.3.547-550.1967

Cited by 54 publications

(14 citation statements)

References 2 publications

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“…of the contribution by these bound bacteria to proteolysis was not attempted. The proteolytic activity present in the bacterial fraction was cell associated, as has been found previously (5,39), and the object of the work reported in the present paper was to identify the cellular location of the proteases and to extract and characterize them.…”

Section: Discussionsupporting

confidence: 56%

Cellular Location and Some Properties of Proteolytic Enzymes of Rumen Bacteria

Kopečný¹,

Wallace²

1982

Appl Environ Microbiol

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Several physical and chemical techniques were used to extract, and to identify the location of, proteolytic enzymes associated with mixed rumen bacteria. Most activity was removable by gentle physical methods such as shaking and brief blending, without cell disruption, indicating that it was associated with coat and capsular material. Proteases were present also in the cell envelope, corresponding to the inner membrane fraction of gram-negative bacteria, and intracellularly and were removable by detergent and French press treatment. Temperature and pH profiles were obtained for the coat enzymes, likely to be the most important in the digestion of food protein. Inhibition studies indicated that these proteases, and those of the whole bacterial fraction from rumen fluid, were predominantly of the cysteine protease type.

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Section: Discussionsupporting

confidence: 56%

Cellular Location and Some Properties of Proteolytic Enzymes of Rumen Bacteria

Kopečný¹,

Wallace²

1982

Appl Environ Microbiol

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“…According to van Gylswyk (1990), P. ruminacola can comprise 60% of a rumen flora; on the basis of the present study such a population would deal more rapidly and efficiently with peptides rather than amino acids. Therefore, reports of preferential uptake of peptides may be due to high proportions of P. ruminicola in incubations of mixed rumen bacteria (Wright 1967;Prins et al 1979;Cooper and Ling 1985). Conversely, conflicting reports (Parker 1990;Armstead and Ling 1993) may be caused by low proportions of this particular species and high levels of others, such as S. ruminantiurn, which can account for up to 51% of a rumen flora (Caldwell and Bryant 1966), and which has a greater preference for amino acids rather than peptides (Fig.…”

Section: General Considerations Of Peptlde and Amlno Acid Uptake And mentioning

confidence: 99%

The in vitro uptake and metabolism of peptides and amino acids by five species of rumen bacteria

Ling

Armstead

1995

Journal of Applied Bacteriology

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Streptococcus bovis JB1, Prevotella ruminicola B(1)4, Selenomonas ruminantium Z108, Fibrobacter succinogenes S85 and Anaerovibrio lipolytica 5S were incubated with either 14C-peptides (mol. wt, 200-1000) or 14C-amino acids to compare their rates of uptake and metabolism. In experiment 1, the bacteria were grown and incubated in a complex medium, but no uptake of 14C-labelled substrates occurred. When casein digest was omitted, uptake rates of 14C-peptides were different (P < 0.01) with each species, but nil for 14C-amino acids. In experiment 2, to minimize the effects of non-radiolabelled peptides and amino acids, defined and semi-defined media were used. Patterns of 14C-peptide uptake resembled those of experiment 1. The 5-min rate for Strep. bovis JB1 was almost twice that of P. ruminicola B(1)4, though by 15 min they were similar and threefold greater than other species; that of A. lipolytica 5S was especially low. Incubations with 14C-amino acids resulted in a wide range (P < 0.01) of uptake rates; after 5 min P. ruminicola B(1)4 possessed the lowest and Strep. bovis JB1 the highest, but after 15 min, that of Sel. ruminantium Z108 was even higher. All bacteria, with the exception of P. ruminicola B(1)4, assimilated 14C-amino acids faster (P < 0.01) than 14C-peptides. Only Strep. bovis JB1 and P. ruminicola B(1)4 were capable of extensively metabolizing 14C-peptides, but all five species metabolized 14C-amino acids; there was evidence of substantial degradation and some synthesis. Calculations suggest that peptides could supply up to 43%, and amino acids 62% of the N requirements of rumen bacteria.

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“…The fate of peptides and amino acids in the ruminal ecosystem has been studied from a number of perspectives, including measuring their effects on microbial growth (3,15,22), their fermentation and production of ammonia (5, 9, 10), their persistence in rumen fluid (8,35), the activities of microbial peptidase enzymes (30,31), the utilization of specific peptides and amino acids (6,27,37), and the utilization of mixtures of either of these substrates (14,25,38). Despite these and other studies, progress in this research area has been hampered by considerable controversy.…”

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confidence: 99%

Variations in the uptake and metabolism of peptides and amino acids by mixed ruminal bacteria in vitro

Armstead

Ling

1993

Appl Environ Microbiol

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Mixed ruminal bacteria, isolated from sheep (Q and W) fed a concentrate and hay diet, were anaerobically incubated with either 14C-peptides or "4C-amino acids. Experiment 1 showed that uptake of both "4C-labeled substrates was rapid, but the rate for amino acids was twofold greater than for peptides (molecular weight, 1,000 to 200) initially but was similar after 10 min. Experiment 2 demonstrated that metabolism was also rapid; at least 90%o of either "4C-labeled substrate was metabolized by 3 min. Of the radioactivity remaining in bacteria, approximately 30% was in the form of "4C-amino acids, but only in leucine, tyrosine, and phenylalanine. Supernatant radioactivity was contained only in tyrosine, phenylalanine, and mostly proline for incubations with "4C-amino acids but in up to 10 amino acids when 14C-peptides were the substrates. Short-term incubations (<5 min; experiment 3) confirmed previous uptake patterns and showed that the experimental system was responsive to substrate competition. Experiment 4 demonstrated that bacteria from sheep Q possessed initial and maximum rates of "4C-amino acid uptake approximately fourfold greater (P < 0.01) than those of "4C-peptides, but with no significant differences (P > 0.1) between four "4C-peptide substrate groups with molecular weights of 2,000 to <200. By contrast, bacteria from sheep W showed no such distinctions (P > 0.1) between rates for "4C-peptides and "4C-amino acids. Calculations suggested that peptides could supply from 11 to 35% and amino acids could supply from 36 to 68% of the N requirements of mixed ruminal bacteria. The variations of these findings and their implications for future research are discussed.

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Metabolism of Peptides by Rumen Microorganisms

Cited by 54 publications

References 2 publications

Cellular Location and Some Properties of Proteolytic Enzymes of Rumen Bacteria

Cellular Location and Some Properties of Proteolytic Enzymes of Rumen Bacteria

The in vitro uptake and metabolism of peptides and amino acids by five species of rumen bacteria

Variations in the uptake and metabolism of peptides and amino acids by mixed ruminal bacteria in vitro

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