ENZYMES ASSOCIATED WITH METABOLISM OF XYLOSE AND OTHER PENTOSES BY PREVOTELLA (BACTEROIDES) RUMINICOLA STRAINS, SELENOMONAS-RUMINANTIUM D, AND FIBROBACTER-SUCCINOGENES S85

被引:40
作者
MATTE, A
FORSBERG, CW
GIBBINS, AMV
机构
[1] UNIV GUELPH,DEPT MICROBIOL,GUELPH N1G 2W1,ONTARIO,CANADA
[2] UNIV GUELPH,DEPT ANIM & POULTRY SCI,GUELPH N1G 2W1,ONTARIO,CANADA
关键词
FIBROBACTER-SUCCINOGENES; PREVOTELLA; SELENOMONAS; XYLOSE METABOLISM; RUMEN BACTERIA; PENTOSE PHOSPHATE CYCLE;
D O I
10.1139/m92-063
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Prevotella (Bacteroides) ruminicola strains B(1)4 and S23 and Selenomonas ruminantium strain use xy se sole source of carbohydrate for growth, whereas Fibrobacter succinogenes was unable to metabolize xylose. Prevotella ruminicola strain B(1)4 exhibited transport activity for xylose. In contrast, F. succinogenes lacked typical xylose uptake activity but did exhibit low binding potential for the sugar. Prevotella ruminicola strains B(1)4 and S23 as well as S. ruminantium D showed low xylose isomerase activities but higher xylulokinase activities, using assays that gave high activities for these enzymes in Escherichia coli. Xylose isomerase appeared to be produced constitutively in these ruminal bacteria, but xylulokinase was induced to varying degrees with xylose as the source of carbohydrate. Fibrobacter succinogenes lacked xylose isomerase and xylulokinase. All three species of ruminal bacteria possessed transketolase, xylulose-5-phosphate epimerase, and ribose-5-phosphate isomerase activities. Neither P. ruminicola B(1)4 nor F. succinogenes S85 showed significant phosphoketolase activity. The data indicate that F. succinogenes is unable to either actively uptake or metabolize xylose as a result of the absence of functional xylose permease, xylose isomerase, and xylulokinase activities, although it and both P. ruminicola and S. ruminantium possess the essential enzymes of the nonoxidative branch of the pentose phosphate cycle.
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页码:370 / 376
页数:7
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