Oligopeptide Uptake by Bacteroides ruminicola

Abstract

Bacteroides ruminicola did not take up 14C from exogenous "C-labeled L-proline or 14C-labeled L-glutamic acid and took up very little 14C from exogenous 4C-labeled L-valine. Growing cultures of B. ruminicola rapidly took up 14C from "4C-prolinelabeled peptides of molecular weights up to 2,000 and incorporated it into trichloroacetic acid-insoluble cell material. Uptake and incorporation did not occur at 0 C and were reduced or eliminated in glucose-starved cells, depending upon the length of time the cells were starved. The initial rate of uptake of peptides seemed to exhibit saturation kinetics, but it was impossible to establish this conclusively. The initial uptake of 14C from peptides was not affected by chloramphenicol but the incorporation of it into trichloroacetic acid-insoluble cell material was virtually eliminated. Only moderate amounts of trichloroacetic acid-extractable, labeled material were present in cells during peptide uptake, whether or not chloramphenicol was present. "4C-proline was rapidly released from labeled peptides during uptake, whether or not chloramphenicol was present. The amount of "IC fixed into trichloroacetic acid-insoluble cell material was directly related to the size of peptides originally supplied in the medium. It is concluded that B. ruminicola possesses a general system for the uptake of peptides, that peptides are rapidly hydrolyzed during or after uptake, and that oligopeptides function only to supply amino acids in a form available to the organism.

Enumeration of amino acid fermenting bacteria in the human large intestine: effects of pH and starch on peptide metabolism and dissimilation of amino acids

“…The ability of microorganisms to assimilate peptides instead of free amino acids is energetically advantageous, and would be physiologically important in an energy de¢cient environment such as the large intestine. Peptide stimulation of growth has been observed in Prevotella ruminicola [9], but is not only con¢ned to single isolates, since mixed cultures of rumen microorganisms have been shown to utilise N from ammonia or peptides, but not from amino acids [42,43].…”

“…Evidence suggests that intestinal anaerobes prefer to assimilate N in the form of peptides or ammonia, rather than as free amino acids [6^8]. Peptides have been shown to stimulate growth of many rumen organisms, for example Prevotella ruminicola utilises N from ammonia or peptides but not amino acids [8,9]. Bacteroides fragilis [10] and Ruminobacter amylophilus [11] also fail to use amino acids as the sole source of energy, however, amino acids are assimilated by these organisms via six transport systems and are rapidly incorporated into cellular material, provided a source of ammonia is available [12].…”

Utilization of amino acids and peptides by Fusobacterium nucleatum

“…For many organisms peptides are of considerable nutritional importance, and distinct peptide transport systems have been identified (24,25). In the family of Bacteroidaceae it has been reported that some Bacteroides species are able to grow upon peptides, but not upon free amino acids (13,26,27).…”

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

“…Most in vitro studies of peptide and amino acid utilization by rumen bacteria have been conducted with mixed populations (Wallace and Cotta 1988;Broderick et al 1991 ;Russell et al 1991). Some classical studies with single species of bacteria and peptide substrates were published during the 1960s (Pittman and Bryant 1964;Pittman et al 1967), but virtually nothing further was reported until the 1980s, as exemplified by the work of Russell (1983). Even I988), and in particular, Preuotella (formerly Bacteroides) rurninicola (Pittman and Bryant 1964;Pittman et al 1967;Munn et al 1983;Russell 1983;McKain et al 1992;Newbold et al 1992;Wallace et al 1993).…”

“…Some classical studies with single species of bacteria and peptide substrates were published during the 1960s (Pittman and Bryant 1964;Pittman et al 1967), but virtually nothing further was reported until the 1980s, as exemplified by the work of Russell (1983). Even I988), and in particular, Preuotella (formerly Bacteroides) rurninicola (Pittman and Bryant 1964;Pittman et al 1967;Munn et al 1983;Russell 1983;McKain et al 1992;Newbold et al 1992;Wallace et al 1993). Furthermore, comparative studies, involving a number of bacterial species, have been limited to examinations of either general biological functions, such as growth efficiency (Cotta and Russell 1982), or very specific attributes, such as peptidase activity (Wallace and McKain 1991;McKain et al 1992).…”