Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8530, Japan.
Biotechnol Lett. 2013 May;35(5):695-701. doi: 10.1007/s10529-012-1133-y. Epub 2013 Jan 4.
phoU mutants of bacteria are potentially useful for the removal of inorganic phosphate (Pi) from sewage because they can accumulate a large amounts of polyphosphate (polyP). However, the growth of phoU mutants is severely defective and is easily outgrown by revertant(s) that have lost the ability to accumulate polyP during growth in a nutrient-rich medium. We found that a pseudo-revertant, designated LAP[+], that appeared in a culture of an Escherichia coli phoU mutant that could accumulate polyP even after ten serial passages. Reduction in the expression of the Pi-specific transporter Pst in LAP[+] may contribute to relieving stresses such as excess Pi incorporation that could stimulate reversions. The discovery of a LAP[+] provides a clue to generate phoU mutants that accumulate polyP in a stable manner.
细菌 phoU 突变体在去除污水中的无机磷酸盐 (Pi) 方面具有潜在的应用价值，因为它们可以积累大量的多磷酸盐 (polyP)。然而， phoU 突变体的生长严重受损，并且很容易被在富含营养的培养基中生长时失去积累 polyP 能力的回复突变体所超过。我们发现，一个假回复突变体，被指定为 LAP[+]，出现在一株能够积累 polyP 的大肠杆菌 phoU 突变体的培养物中，即使经过十次连续传代后也是如此。LAP[+]中 Pi 特异性转运蛋白 Pst 的表达减少可能有助于缓解过度 Pi 掺入等应激，从而刺激回复突变。LAP[+]的发现为产生以稳定方式积累 polyP 的 phoU 突变体提供了线索。
