Significance of Legionella pneumophila phospholipases for modification of lipids within the phagosomal membrane

军团病是军团病的病原体，军团病是一种潜在的严重肺炎。磷脂酶可例如通过修饰真核细胞膜而促进细菌毒力。已经描述了L.的至少15种磷脂酶A，其部分也显示溶血磷脂酶A和/或甘油磷脂：胆固醇酰基转移酶活性。嗜肺菌这些活性中的大多数通过IVB型（Dot/Icm）分泌、II型（Lsp）分泌或通过外膜囊泡递送到宿主细胞中，因此它们可能存在于含军团菌的吞噬体中。据报道，在军团菌感染后几分钟内，吞噬体膜发生显著变化，转化为内质网样区室。然而，军团菌吞噬体的脂质组成以及磷脂酶是否有助于脂质重排目前尚不清楚，将通过以下目的进行研究：1.选择的L.嗜肺磷脂酶，2.）从野生型、分泌型和磷脂酶突变型感染中分离含军团菌的吞噬体并检查吞噬体脂质体，3.）感染宿主细胞内特异性磷脂酶的定位。

Legionellae are the causative agent of Legionnaires’ disease, a potentially severe pneumonia. Phospholipases may contribute to bacterial virulence, for example via modification of eukaryotic membranes. At least 15 phospholipases A which in part also show lysophospholipase A and/or glycerolphospholipid:cholesterol acyltransferase activity have been described for L. pneumophila. Most of those activities are delivered into the host cell via type IVB (Dot/Icm) secretion, type II (Lsp) secretion, or by means of outer membrane vesicles and they might consequently be present in the Legionella-containing phagosome. It has been described that dramatic changes occur at the phagosomal membrane which is transformed into an endoplasmic reticulum-like compartment within minutes after Legionella infection. However, the lipid composition of the Legionella phagosome and whether phospholipases contribute to the lipid rearrangements is currently not known and will be investigated by the following objectives: 1.) Determination of eukaryotic target lipids of selected L. pneumophila phospholipases, 2.) Isolation of Legionella-containing phagosomes from wild type, secretion, and phospholipase mutant infections and examination of the phagosomal lipidome, 3.) Localization of specific phospholipases within an infected host cell.