Williams D K, Martin S A
Department of Microbiology, University of Georgia, Athens 30602.
Appl Environ Microbiol. 1990 Jun;56(6):1683-8. doi: 10.1128/aem.56.6.1683-1688.1990.
Selenomonas ruminantium HD4 does not use the phosphoenolpyruvate phosphotransferase system to transport xylose (S. A. Martin and J. B. Russell, J. Gen. Microbiol. 134:819-827, 1988). Xylose uptake by whole cells of S. ruminantium HD4 was inducible. Uptake was unaffected by monensin or lasalocid, while oxygen, o-phenanthroline, and HgCl2 were potent inhibitors. Menadione, antimycin A, and KCN had little effect on uptake, and acriflavine inhibited uptake by 23%. Sodium fluoride decreased xylose uptake by 10%, while N,N'-dicyclohexylcarbodiimide decreased uptake by 31%. Sodium arsenate was a strong inhibitor (83%), and these results suggest the involvement of a high-energy phosphate compound and possibly a binding protein in xylose uptake. The protonophores carbonyl cyanide m-chlorophenylhydrazone, 2,4-dinitrophenol, and SF6847 inhibited xylose uptake by 88, 82, and 43%, respectively. The cations Na+ and K+ did not stimulate xylose uptake. The kinetics of xylose uptake were nonlinear, and it appeared that more than one uptake mechanism may be involved or that two proteins (i.e., a binding protein and permease protein) with different affinities for xylose were present. Excess (10 mM) glucose, sucrose, or maltose decreased xylose uptake less than 40%. Uptake was unaffected at extracellular pH values between 6.0 and 8.0, while pH values of 5.0 and 4.0 decreased uptake 28 and 24%, respectively. The phenolic monomers p-coumaric acid and vanillin inhibited growth on xylose and xylose uptake more than ferulic acid did. The predominant end products resulting from the fermentation of xylose were lactate (7.5 mM), acetate (4.4 mM), and propionate (5.1 nM), and the Yxylose was 24.1 g/mol.
反刍月形单胞菌HD4不利用磷酸烯醇式丙酮酸磷酸转移酶系统转运木糖（S. A. 马丁和J. B. 拉塞尔，《普通微生物学杂志》134:819 - 827，1988年）。反刍月形单胞菌HD4全细胞对木糖的摄取是可诱导的。莫能菌素或拉沙洛西对摄取没有影响，而氧气、邻菲罗啉和HgCl₂是有效的抑制剂。甲萘醌、抗霉素A和KCN对摄取影响很小，吖啶黄素抑制摄取23%。氟化钠使木糖摄取减少10%，而N，N'-二环己基碳二亚胺使摄取减少31%。砷酸钠是一种强抑制剂（83%），这些结果表明一种高能磷酸化合物以及可能一种结合蛋白参与了木糖摄取。质子载体羰基氰化物间氯苯腙、2,4 - 二硝基苯酚和SF6847分别抑制木糖摄取88%、82%和43%。阳离子Na⁺和K⁺不刺激木糖摄取。木糖摄取动力学是非线性的，似乎可能涉及不止一种摄取机制，或者存在两种对木糖具有不同亲和力的蛋白质（即一种结合蛋白和通透酶蛋白）。过量（10 mM）的葡萄糖、蔗糖或麦芽糖使木糖摄取减少不到40%。在细胞外pH值为6.0至8.0之间时摄取不受影响，而pH值为5.0和4.0时分别使摄取减少28%和24%。酚类单体对香豆酸和香草醛对木糖上生长和木糖摄取的抑制作用比对阿魏酸的抑制作用更强。木糖发酵产生的主要终产物是乳酸（7.5 mM）、乙酸（4.4 mM）和丙酸（5.1 nM），木糖得率为24.1 g/mol。
