Johnston M A, Thatcher F S
Appl Microbiol. 1967 Sep;15(5):1223-7. doi: 10.1128/am.15.5.1223-1228.1967.
Phenethyl beta-d-galactopyranoside (PEG) was hydrolyzed by the beta-galactosidase of Escherichia coli to form the toxic product phenethyl alcohol. Salmonella typhimurium did not hydrolyze PEG. In mixed culture, the ratio of S. typhimurium to E. coli was increased by growing the organisms in lactose broth containing 2.5% PEG. The high concentration of PEG required for inhibition of E. coli can be attributed to inadequate cell permeability rather than to prevention of beta-galactosidase induction.
β-D-吡喃半乳糖苯乙酯(PEG)被大肠杆菌的β-半乳糖苷酶水解形成有毒产物苯乙醇。鼠伤寒沙门氏菌不水解PEG。在混合培养中,通过在含有2.5%PEG的乳糖肉汤中培养生物体,鼠伤寒沙门氏菌与大肠杆菌的比例增加。抑制大肠杆菌所需的高浓度PEG可归因于细胞通透性不足,而非阻止β-半乳糖苷酶的诱导。