Phosphatidylcholine Affects the Secretion of the Alkaline Phosphatase PhoA in Pseudomonas Strains

Publication date: Available online 20 May 2016 Source:Microbiological Research Author(s): Xin Liu, Deliang Long, Heng You, Dingpeng Yang, Shuang Zhou, Shuting Zhang, Mengqiu Li, Miao He, Ming Xiong, Xingguo Wang Pseudomonas aeruginosa ATCC 27853 and Pseudomonas sp. 593 use the phosphatidylcholine synthase pathway (Pcs-pathway) for the biosynthesis of phosphatidylcholine (PC). Both bacterial strains contain the phoA and lapA genes encoding alkaline phosphatases (ALP) and display strong ALP activities. The PhoA and LapA enzymes are thought to be independently secreted via the Xcp and Hxc type II secretion system (T2SS) subtypes, in which the Hxc system may act as a complementary mechanism when the Xcp pathway becomes limiting. Inactivation of the pcs gene in both bacteria abolished PC synthesis and resulted in approximately 50% less ALP activity in the cell-free culture. Analysis by western blotting showed that LapA protein content in the wild type and the pcs− mutant was unchanged in the cytoplasmic, periplasmic or extracellular protein fractions. In contrast, the PhoA protein in the pcs− mutant was less prevalent among extracellular proteins but was more abundant in the periplasmic protein fraction compared to the wild type. Semi-quantitative reverse transcriptase PCR showed that phoA, lapA and 12 xcp genes were equally expressed at the transcriptional level in both the wild types and the pcs− mutants. Our results demonstrate that the absence of...
Source: Microbiological Research - Category: Infectious Diseases Source Type: research