菊欧文氏菌中的乳糖和蜜二糖代谢
Lactose and melibiose metabolism in Erwinia chrysanthemi.
作者信息
Gray J S, Lindner W A, Brand J M, Mildenhall J P
出版信息
J Bacteriol. 1986 Nov;168(2):886-91. doi: 10.1128/jb.168.2.886-891.1986.
A Lac+ mutant of Erwinia chrysanthemi was isolated from the Lac- wild type on lactose agar. beta-Galactosidase was expressed independently of lactose transport in both the mutant and the wild type, and neither strain expressed thiogalactoside transacetylase. Lactose transport and alpha-galactosidase, constitutive in the Lac+ strain, were coordinately induced in the Lac- strain by melibiose and raffinose but not by isopropyl-beta-D-thiogalactopyranoside or thiomethyl-beta-D-galactopyranoside. Melibiose was a strong inhibitor of both the melibiose- and the raffinose-induced lactose permeases, whereas raffinose was a strong inhibitor of only the raffinose-induced lactose permease.
从乳糖琼脂平板上的乳糖阴性野生型菌株中分离出了菊欧文氏菌的乳糖阳性突变体。β-半乳糖苷酶在突变体和野生型菌株中均独立于乳糖转运而表达，且两种菌株均不表达硫代半乳糖苷转乙酰酶。乳糖转运和α-半乳糖苷酶在乳糖阳性菌株中组成型表达，在乳糖阴性菌株中由蜜二糖和棉子糖协同诱导表达，但不受异丙基-β-D-硫代半乳糖苷或硫代甲基-β-D-吡喃半乳糖苷诱导。蜜二糖是蜜二糖和棉子糖诱导的乳糖通透酶的强抑制剂，而棉子糖仅是棉子糖诱导的乳糖通透酶的强抑制剂。
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