Department of Animal Sciences, Washington State University, Pullman, Washington 99164-6320.
Appl Environ Microbiol. 1990 May;56(5):1373-7. doi: 10.1128/aem.56.5.1373-1377.1990.
A study was conducted to determine the activity of the 3-methylindole (3MI)-forming enzyme in Lactobacillus sp. strain 11201. Cells were incubated anaerobically with 17 different indolic and aromatic compounds. Indoleacetic acid (IAA), 5-hydroxyindoleacetic acid, 5-methoxy-3-indoleacetic acid, indole-3-pyruvate, or indole-3-propionic acid induced 3MI-forming activity. The highest total enzyme activity induced by IAA was observed in cells incubated with an initial concentration of 1.14 mM IAA. Peak activity of the 3MI-forming enzyme occurred 4 h after bacteria were incubated with either 0.114 or 1.14 mM IAA. Enzyme activity peaked earlier (2 h) and disappeared more rapidly at 5.7 mM IAA than at other concentrations of IAA. The effects of IAA and 3MI on the growth of Lactobacillus sp. strain 11201 and formation of 3MI from IAA also were determined. Bacterial growth and 3MI formation from IAA were reduced in medium containing exogenous 3MI. The growth depression observed in medium containing 5.7 mM IAA appears to be due to the toxicity of 3MI rather than IAA. The formation of 3MI in this ruminal Lactobacillus sp. is mediated by an inducible enzyme, and as 3MI accumulates, bacterial growth and rates of 3MI formation from IAA are reduced.
一项研究旨在确定乳酸菌 11201 菌株中 3-甲基吲哚（3MI）形成酶的活性。细胞在厌氧条件下与 17 种不同的吲哚和芳香族化合物孵育。吲哚乙酸（IAA）、5-羟基吲哚乙酸、5-甲氧基-3-吲哚乙酸、吲哚-3-丙酮酸或吲哚-3-丙酸诱导 3MI 形成活性。用 1.14mM IAA 孵育细胞时观察到的 IAA 诱导的总酶活性最高。3MI 形成酶的峰值活性出现在细菌用 0.114 或 1.14mM IAA 孵育 4 小时后。与其他 IAA 浓度相比，在 5.7mM IAA 中，酶活性更早（2 小时）达到峰值并更快消失。还确定了 IAA 和 3MI 对乳酸菌 11201 生长和从 IAA 形成 3MI 的影响。在含有外源性 3MI 的培养基中，细菌生长和从 IAA 形成 3MI 减少。在含有 5.7mM IAA 的培养基中观察到的生长抑制似乎是由于 3MI 的毒性而不是 IAA。这种瘤胃乳酸菌中 3MI 的形成是由诱导酶介导的，随着 3MI 的积累，细菌生长和从 IAA 形成 3MI 的速度降低。
