The Cytosolic Oligosaccharide-Degrading Proteome of Butyrivibrio Proteoclasticus

Abstract

The growth and productivity of ruminants depends on a complex microbial community found in their fore-stomach (rumen), which is able to breakdown plant polysaccharides and ferment the released sugars. Butyrivibrio proteoclasticus B316T is a Gram-positive polysaccharide-degrading, butyrate-producing bacterium that is present at high numbers in the rumen of animals consuming pasture or grass silage based diets. B316T is one of a small number of rumen fibrolytic microbes capable of efficiently degrading and utilizing xylan, as well as being capable of utilizing arabinose, xylose, pectin and starch. We have therefore carried out a proteomic analysis of B316T to identify intracellular enzymes that are implicated in the metabolism of internalized xylan. Three hundred and ninety four proteins were identified including enzymes that have potential to metabolize assimilated products of extracellular xylan digestion. Identified enzymes included arabinosidases, esterases, an endoxylanase, and β-xylosidase. The presence of intracellular debranching enzymes indicated that some hemicellulosic side-chains may not be removed until oligosaccharides liberated by extracellular digestion have been assimilated by the cells. The results support a model of extracellular digestion of hemicellulose to oligosaccharides that are then transported to the cytoplasm for further digestion by intracellular enzymes.

Diversified gut microbiota in newborns of mothers with gestational diabetes mellitus

“…These unique species may have an association with host metabolism and disease and should be caught on attention. For example, the genus Butyrivibrio has been regarded as a key bacterium in polysaccharide degrading and butyrate producing [ 29 ], however, it was not detected in GDM group.…”

Butyrivibrio hungateiMB2003 Competes Effectively for Soluble Sugars Released byButyrivibrio proteoclasticusB316Tduring Growth on Xylan or Pectin

“…Butyrivibrio species have Gram-positive cell wall structures (21), and monosaccharide transport across the bacterial cell wall is mediated by a variety of extracellular SBPs linked to dedicated sugar ABC transporter systems (19, 20). Recent data on the B316 T secretome (44, 46) and carbohydrate-transport-associated membrane proteins (45), as well as genome sequence analysis of MB2003 (19, 20), identified a large number of sugar-specific ABC transporter SBPs. Overall, analysis of MB2003 upregulated SBPs and their functional domains, along with surrounding genes encoding polysaccharide-degrading enzymes, revealed that the most prevalent functional category was the COG1653 domain, which is known to be associated with oligosaccharide transport (45).…”

Butyrivibrio hungateiMB2003 competes effectively for soluble sugars released byButyrivibrio proteoclasticusB316Tfrom growth on xylan or pectin

“…Butyrivibrio have Gram-positive cell wall structures (10-12), and monosaccharide transport across the bacterial cell wall is mediated by a variety of extracellular SBPs linked to dedicated sugar ABC transporter systems. Recent data on the B316 T secretome (34, 36) and carbohydrate transport-associated membrane proteins (35), as well as genome sequence analysis of MB2003 (10, 11), identified a large number of sugar-specific ABC transporter SBPs.…”