Toxoplasma gondii secretes a calcium-independent phospholipase A₂

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• 作者：Cassaing ; Sophie ; Fauvel ; Josette ; Bessiè ; res ; Marie-H&eacute ; lè ; ne ; Guy ; Sandrine ; et. al.
• 关键词：Toxoplasma gondii ; Phospholipase A₂ ; Spectrofluorimetry ; Fluorescent phospholipid ; Thin-layer chromatography
• 刊名：International Journal for Parasitology
• 出版年：2000
• 期刊代码：124_00207519
• 类别：med
• 出版时间：October, 2000
• 卷：30
• 期：11
• 页码：1137-1142
• 文件大小：215 K

摘要

Phospholipases A₂ (PLA₂) play an important role in Toxoplasma gondii host cell penetration. They are also key enzymes in the host cell response to the parasite invasion. PLA₂ hydrolyse cellular phospholipids, releasing multiple inflammatory lipidic mediators. We have investigated the biochemical characterisation of T. gondii PLA₂ activity in a mouse-cultured tachyzoite homogenate and in the peritoneal exudate from infected mice, using the hydrolysis of a fluorescent phosphatidylglycerol labelled at the sn-2 position. Spectrofluorimetry and thin-layer chromatography showed a PLA₂ activity (about 0.5–2 nmol/min per mg), calcium-independent, secreted into infected mice peritoneal exudate, with a broad pH activity ranging between 6.5 and 9.5 and resistant to a great number of potential PLA₂ inhibitors except dithio-nitrobenzoic acid (1 mM). An associated phospholipase A₁ activity was also displayed. These results suggest that Toxoplasma gondii displays specific phospholipases different from host enzymes and probably involved at critical steps of infectious cycle.