Polyphosphate kinase of Lysinibacillus sphaericus and its effects on accumulation of polyphosphate and bacterial growth

Publication date: Available online 12 December 2014 Source:Microbiological Research Author(s): Tingyu Shi , Yong Ge , Ni Zhao , Xiaomin Hu , Zhiming Yuan Lysinibacillus sphaericus produces parasporal crystal proteins (Bin toxins) that are specifically toxic to Culex and Anopheles mosquito larvae. It has long persistence in mosquito breeding sites due to the recycle of spores in mosquito cadaver and certain environments. This bacterium is unable to metabolize sugar (except N-acetylglucosamine) but can use proteinaceous materials. Previous studies have shown that inorganic polyphosphate (polyP) is essential for cell growth and responses to nutritional stringencies and environmental stresses and branched-chain amino acids (BCAAs) are useful intracellular signals for bacterial adaption to nutritional environments. However, relatively little is known about the role of polyP and the regulation link between polyP and BCAAs in nutritional limitation adaptation in a bacterium incapable of polysaccharide utilization. Here, a primary enzyme involved in polyP biosynthesis, polyphosphate kinase (PPK), was identified from L. sphaericus, and the polyP accumulation in different nutritional media was investigated. Furthermore, a ppk null mutant and the ppk-complemented strain were constructed and the effect of deletion on cell growth, polyP accumulation and expression of BCAAs biosynthetic genes (ilvBHC) was surveyed. The result showed that deletion of ppk resulted in a deficiency i...
Source: Microbiological Research - Category: Infectious Diseases Source Type: research