Factors affecting glucose uptake by the ruminal bacterium Bacteroides ruminicola

Abstract

Glucose uptake by whole cells of Bacteroides rurninicola B14 is constitutive. Potassium concentrations between 10 and 150 mM stimulated uptake over fourfold, while sodium had little effect on uptake. The involvement of potassium in glucose uptake by B. ruminicola was supported by strong inhibition of uptake by the ionophores valinomycin, lasalocid, and monensin. The electron transport inhibitor antimycin A had little effect on uptake, but menadione and acriflavine inhibited uptake by 30 and 48%, respectively. Potent inhibitors of uptake included oxygen, p-chloromercuribenzoate, HgCI2, and o-phenanthroline. Sodium arsenate decreased uptake by 40%, suggesting that a highenergy phosphate compound and possibly a binding protein may be involved in glucose uptake. The protonophores carbonyl cyanide m-chlorophenylhydrazone and 2,4-dinitrophenol inhibited glucose uptake by 37 and 22%, respectively. Little change in uptake activity was observed at extracellular pH values between 4.0 and 8.0. Excess (10 mM) cellobiose, maltose, and sucrose inhibited glucose uptake less than 15%. High levels (0.15% w/v) of p-coumaric acid and vanillin decreased uptake by 32 and 37%, respectively, while 0.15% ferulic acid decreased uptake by 15%.

Effects of extracellular pH and phenolic monomers on glucose uptake by Fibrobacter succinogenes S85

“…p-Coumaric acid and vanillin were the most potent inhibitors of glucose uptake by F. succinogenes S85, while ferulic acid was less inhibitory (Table 1). Similar results were observed for glucose uptake in Bacteroides ruminicola (Martin 1992) and xylose uptake in Selenomonas ruminantium (Williams & Martin 1990). The inhibition of uptake by these compounds helps to partially explain the initial growth inhibition observed when F. succinogenes is exposed to these compounds (Chesson et al 1982;Varel & Jung 1986).…”

“…Uptake of ~-[U-'~C]-glucose (ICN Biomedicals, Inc., Costa Mesa, CA, USA) was examined in glucose-grown cells as previously described (Williams & Martin 1990;Martin 1992). Effects of extracellular pH on glucose uptake were determined by incubating cells in anaerobic (N, atmosphere) phosphate buffers (100 mM sodium-potassium phosphate plus 5 mM MgCI,) adjusted to pH values of 8.0, 7.2, 6.5, 5.0, and 4.0 (Williams & Martin 1990;Martin 1992).…”

The Rumen Microbial Ecosystem

“…F. succinogenes has sodium symport reactions for glucose (Franklund and Glass, 1986;Chow and Russell, 1992) and cellobiose (Maas and Glass, 1991). A glucose transporter in P. ruminicola was stimulated by potassium, but not sodium, ions (Martin, 1992). A glucose transporter in P. ruminicola was stimulated by potassium, but not sodium, ions (Martin, 1992).…”

Effects of an Aspergillus oryzae fermentation extract and other factors on lactate utilization by the ruminal bacterium Megasphaera elsdenii

“…These results suggest that neither sodium nor potassium is involved in L-lactate uptake by M. elsdenii. High concentrations of sodiulh or potassium also tended to decrease xylose uptake by S. ruminantium HD4 (Williams and Martin, 19901, whereas potassium concentrations between 10 and 150 mM stimulated glucose uptake by Bacteroides ( Prevotella) ruminicola (Martin, 1992).…”