ABILITY OF ACIDAMINOCOCCUS-FERMENTANS TO OXIDIZE TRANS-ACONITATE AND DECREASE THE ACCUMULATION OF TRICARBALLYLATE, A TOXIC END-PRODUCT OF RUMINAL FERMENTATION
ABILITY OF ACIDAMINOCOCCUS-FERMENTANS TO OXIDIZE TRANS-ACONITATE AND DECREASE THE ACCUMULATION OF TRICARBALLYLATE, A TOXIC END-PRODUCT OF RUMINAL FERMENTATION
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DOI：
10.1128/aem.60.7.2533-2537.1994
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发表时间：
1994-07-01
影响因子：
4.4
通讯作者：
RUSSELL, JB
中科院分区：
文献类型：
--
作者：
COOK, GM;WELLS, JE;RUSSELL, JB
混合的瘤胃细菌将反乌头酸转化为丙三羧酸，丙三羧酸是一种螯合血液二价阳离子并降低其可用性的三羧酸（J.B. Russell和P.J.货车索斯特，Appl Environ. Microbiol. 47：155 - 159，1984）。血镁的减少反过来会导致一种潜在的致命疾病，称为草手足抽搐。反式丙酸被反刍月形单胞菌（Selenomonasruminantium）化学计量地还原为丙三羧酸，反刍月形单胞菌是草饲反刍动物中常见的瘤胃细菌（J.B. Russell，Appl. Environ. Microbiol. 49：120 - 126，1985）。当混合瘤胃细菌富集反式乌头酸时，还分离到一种反式乌头酸氧化细菌（G。M.库克，佛罗里达州Rainey，G. Chen，中国山茱萸E. Stackebrandt和J.B. Russell，Int. J.系统细菌学。44：576 - 578，1994）。反式乌头酸氧化细菌被鉴定为发酵氨基酸球菌，它将反式乌头酸转化为乙酸，这是一种无毒的瘤胃发酵终产物。当S. ruminantium和A.将发酵多糖与反式乌头酸和葡萄糖共培养，丙三羧酸从不积累，并且所有的反式乌头酸转化为乙酸。连续培养研究（稀释率为0.1h~（-1））同样表明A.发酵菌可以胜过S.反乌头酸的反刍动物。当混合的瘤胃细菌在体外孵育10 mM的trans-aconitate为24小时，45%的trans-aconitate转化为丙三羧酸。即使是少量的A.向温育混合物中加入发酵多糖（每毫克混合细菌蛋白质加入0.01毫克蛋白质）。当A.将发酵曲霉（2g细菌蛋白）直接加入到瘤胃中，随后的反乌头酸到丙三羧酸的转化率降低了50%，但是这种效果不持续超过18小时。发酵曲霉最终被冲出瘤胃，因为饲喂给奶牛的干草饮食不包含可被发酵曲霉利用的能量源。由于其快速的反乌头酸氧化速率和与其他瘤胃细菌竞争反乌头酸的能力，A。发酵素可能具有防止与草手足抽搐相关的丙三羧酸水平突然增加的潜力。
Mixed ruminal bacteria convert trans-aconitate to tricarballylate, a tricarboxylic acid which chelates blood divalent cations and decreases their availability (J.B. Russell and P.J. Van Soest, Appl Environ. Microbiol. 47:155-159, 1984). Decreases in blood magnesium in turn cause a potentially fatal disease known as grass tetany. trans-Aconitate was stoichiometrically reduced to tricarballylate by Selenomonas ruminantium, a common ruminal bacterium in grass-fed ruminants (J.B. Russell, Appl. Environ. Microbiol. 49:120-126, 1985). When mixed ruminal bacteria were enriched with trans-aconitate, a trans-aconitate-oxidizing bacterium was also isolated (G. M. Cook, F.A. Rainey, G. Chen, E. Stackebrandt, and J.B. Russell, Int. J. Syst. Bacteriol. 44:576-578, 1994). The trans-aconitate-oxidizing bacterium was identified as Acidaminococcus fermentans, and it converted trans-aconitate to acetate, a nontoxic end product of ruminal fermentation. When S. ruminantium and A. fermentans were cocultured with trans-aconitate and glucose, tricarballylate never accumulated and all the trans-aconitate was converted to acetate. Continuous-culture studies (dilution rate, 0.1 h-l) likewise indicated that A. fermentans could outcompete S. ruminantium for trans-aconitate. When mixed ruminal bacteria were incubated in vitro with 10 mM trans-aconitate for 24 h, 45% of the trans-aconitate was converted to tricarballylate. Tricarballylate production decreased 50% if even small amounts of A. fermentans were added to the incubation mixes (0.01 mg of protein per mg of mixed bacterial protein). When A. fermentans (2 g of bacterial protein) was added directly to the rumen, the subsequent conversion of trans-aconitate to tricarballylate decreased 50%, but this effect did not persist for more than 18 h.A.fermentans eventually washed out of the rumen because the grass hay diet fed to the cow did not contain energy sources which could be utilized by A.fermentans. Because of its rapid rate of trans-aconitate oxidation and ability to compete with other ruminal bacteria for trans-aconitate, A. fermentans may have potential for preventing the sudden increases in tricarballylate levels which are associated with grass tetany.