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首页> 外文期刊>Infection and immunity >Acetoin production by wild-type strains and a lactate dehydrogenase-deficient mutant of Streptococcus mutans.
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Acetoin production by wild-type strains and a lactate dehydrogenase-deficient mutant of Streptococcus mutans.

机译：野生型菌株和变形链球菌乳酸脱氢酶缺陷型突变体产生的乙缩醛。

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Eleven different laboratory strains of Streptococcus mutans representing the various serogroups were found to produce an average of 6.0 +/- 4.8 mM acetoin when grown in glucose-containing medium under aerobic conditions. None of the strains produced detectable acetoin when grown anaerobically. A lactate dehydrogenase-deficient mutant produced acetoin both aerobically and anaerobically and in substantially greater amounts than the wild-type strains did. Substitution of mannitol for glucose resulted in decreased acetoin production by wild-type strains and the lactate dehydrogenase-deficient mutant, indicating a role for NADH2 in the regulation of the acetoin pathway. Pyruvate incorporated into the growth medium of a wild-type strain caused acetoin to be produced anaerobically and stimulated acetoin production aerobically. Cell extracts of a wild-type S. mutans strain were capable of producing acetoin from pyruvate and were (partly) dependent on thiamine PPi. Extracts prepared from aerobically grown cells had approximately twice the acetoin-producing activity as did extracts prepared from anaerobically grown cells. The results indicate that acetoin production by S. mutans may represent an auxiliary reaction of pyruvate dehydrogenase in this organism.
机译：当在有氧条件下在含葡萄糖的培养基中生长时，发现代表各种血清群的11种不同链球菌实验室变种菌株平均产生6.0 +/- 4.8 mM乙酰丁酸。当厌氧生长时，所有菌株均未产生可检出的乙酰丁香素。乳酸脱氢酶缺陷型突变体在有氧和厌氧条件下均产生乙酰化酶，其产量远高于野生型菌株。甘露糖醇替代葡萄糖会导致野生型菌株和乳酸脱氢酶缺陷型突变体的丙酮生成减少，这表明NADH2在调控乙酰途径中发挥了作用。掺入到野生型菌株的生长培养基中的丙酮酸导致丙酮酸厌氧地产生，并刺激了厌氧乙酸的产生。野生型变形链球菌菌株的细胞提取物能够从丙酮酸中产生丙酮酸，并且（部分地）依赖于硫胺素PPi。由需氧生长的细胞制备的提取物具有约两倍的产乙酰丙酮生成活性，而由需氧生长的细胞制备的提取物具有。结果表明，变形链球菌产生的乙妥英可能代表该生物中丙酮酸脱氢酶的辅助反应。

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