Biville F, Turlin E, Gasser F
Département de Biochimie et Génétique Moléculaire, Institut Pasteur, Paris, France.
J Gen Microbiol. 1991 Aug;137(8):1775-82. doi: 10.1099/00221287-137-8-1775.
In glucose minimal medium a PTS- strain of Escherichia coli [delta (ptsH ptsI crr)] could grow slowly (doubling time, d = 10 h). When the population reached 5 x 10(6) to 2 x 10(7) cells ml-1, mutants growing rapidly (d = 1.5 h) appeared and rapidly outgrew the initial population. These mutants (EF mutants) do not use a constitutive galactose permease for glucose translocation. They synthesize sufficient pyrroloquinoline quinone (PQQ) to yield a specific activity of glucose dehydrogenase (GDH) equivalent to that found in the parent strain grown in glucose minimal medium supplemented with 1 nM-PQQ. Membrane preparations containing an active GDH oxidized glucose to gluconic acid, which was also present in the culture supernatant of EF strains in glucose minimal medium. Glucose utilization is the only phenotypic trait distinguishing EF mutants from the parent strain. Glucose utilization by EF mutants was strictly aerobic as expected from a PQQ-dependent catabolism. The regulation of PQQ production by E. coli is discussed.
在葡萄糖基本培养基中，大肠杆菌的一种磷酸转移酶系统（PTS）缺陷型菌株[Δ(ptsH ptsI crr)]能够缓慢生长（倍增时间，d = 10小时）。当菌数达到5×10⁶至2×10⁷个细胞/毫升时，出现了生长迅速（d = 1.5小时）的突变体，并迅速超过了初始菌数。这些突变体（EF突变体）在转运葡萄糖时不使用组成型半乳糖通透酶。它们合成足够的吡咯喹啉醌（PQQ），以产生与在添加了1 nM - PQQ的葡萄糖基本培养基中生长的亲本菌株相当的葡萄糖脱氢酶（GDH）比活性。含有活性GDH的膜制剂将葡萄糖氧化为葡萄糖酸，葡萄糖酸也存在于EF菌株在葡萄糖基本培养基中的培养上清液中。葡萄糖利用是区分EF突变体与亲本菌株的唯一表型特征。正如依赖PQQ的分解代谢所预期的那样，EF突变体利用葡萄糖严格需氧。本文讨论了大肠杆菌中PQQ产生的调控。
