title: Phospholipase A and glycerophosphodiesterase activities in the cell membrane of  Mycoplasma hyorhinis.
abstract: Mycoplasma hyorhinis, the major contaminant of tissue cultures, has been implicated in a variety of diseases in swine. Most human and animal mycoplasmas remain attached to the surface of epithelial cells. Nonetheless, we have recently shown that M. hyorhinis is able to invade and survive within nonphagocytic melanoma cells. The invasion process may require the damaging of the host cell membrane by either chemical, physical or enzymatic means. In this study, we show that M. hyorhinis membranes possess a nonspecific phospholipase A (PLA) activity capable of hydrolyzing both position 1 and position 2 of 1-acyl-2-(12-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)] aminododecanoyl) phosphatidylcholine. In silico analysis of the M. hyorhinis genome shows that the PLA of M. hyorhinis shares no homology to described phospholipases. The PLA activity of M. hyorhinis was neither stimulated by Ca (2+) nor inhibited by EGTA and had a broad pH spectrum. Mycoplasma hyorhinis also possess a potent glycerophosphodiesterase (GPD), which apparently cleaves the glycerophosphodiester formed by PLA to yield glycerol-3-phosphate. Possible roles of PLA and GPD in invading host eukaryotic cells and in forming mediators upon the interaction of M. hyorhinis with eukaryotic cells are suggested.
authors.affiliation: Department of Microbiology and Molecular Genetics, The Hebrew University-Hadassah Medical School, Jerusalem, Israel.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Kornspan
authors.forename: Shlomo
authors.initials: S
authors.lastname: Rottem
mesh_terms: D009327:4-Chloro-7-nitrobenzofurazan / Q000031:analogs & derivatives / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology; D005456:Fluorescent Dyes; D006868:Hydrolysis; D008969:Molecular Sequence Data; D045790:Mycoplasma hyorhinis / Q000166:cytology / Q000201:enzymology*; D010713:Phosphatidylcholines / Q000378:metabolism; D010741:Phospholipases A / Q000737:chemistry / Q000378:metabolism*; D010727:Phosphoric Diester Hydrolases / Q000737:chemistry / Q000378:metabolism*; D016415:Sequence Alignment
chemical_list: D001426:Bacterial Proteins; D005456:Fluorescent Dyes; D010713:Phosphatidylcholines; C067460:1-oleoyl-2-(12-((7-nitro-2,1,3-benzoxadiazol-4-yl)amino)dodecanoyl)phosphatidylcholine; D010741:Phospholipases A; D010727:Phosphoric Diester Hydrolases; C038133:glycerophosphodiester phosphodiesterase; D009327:4-Chloro-7-nitrobenzofurazan