1. Vinblastine-induced crystals in Toxoplasma
- Author
-
Eliane Porchet
- Subjects
Biology ,Vinblastine ,Microtubules ,chemistry.chemical_compound ,Tubulin ,Glycerol ,Animals ,Humans ,Viability assay ,Ascaris suum ,Ecology, Evolution, Behavior and Systematics ,chemistry.chemical_classification ,Chromatography ,Degranulation ,biology.organism_classification ,Enzyme assay ,Microscopy, Electron ,Lysophosphatidylcholine ,Enzyme ,chemistry ,Lysophospholipase ,biology.protein ,Parasitology ,Crystallization ,Ribosomes ,Toxoplasma ,HeLa Cells - Abstract
termined using Student's t-test. Ascaris suum larval extract damaged peritoneal leucocytes at a concentration range of 1 to 100 mg protein/1 x 106 cells (Table I). Leucocyte suspensions were assayed for lysophospholipase activity by a modification of the method of Ottolenghi (1964, J. Lipid Res. 5: 532537). Tubes containing 0.1 ml of each cell mixture, after incubation with extract, were mixed with 0.5 ml of 12.5% glycerol medium and equilibrated in a 37 C water bath for 4 min. An 0.3ml lysophosphatidylcholine solution (2 x 10-2 M) prewarmed to 37 C, was added to each test tube and allowed to react for 60 min. The reactions were stopped by adding 1.0 ml of 2 N sulfuric acid, 1.0 ml of isopropyl alcohol, and 0.4 ml of water to each test tube. Each sample then received 2.0 ml of heptane, was stirred, the heptane decanted, and free fatty acids in the heptane were quantitated by titration with 0.01 N sodium hydroxide. The amount of lysophospholipase activity in the leucocyte mixtures was directly related to the e t's t-test. Ascaris suum laramount of A. suum larval extract used to stimulate the cell mixture (Table I). Stimulation of lysophospholipase activity was lost when concentrations less than 1 x 10-5 mg A. suum protein were used as stimuli (P > 0.01). Nonviable peritoneal cells also had minimal lysophospholipase activity suggesting that cell viability has an effect on lysophospholipase activity. Mechanisms associated with in vitro lysophospholipase activity have not previously been studied using helminth extracts as stimulators of enzyme activity. The results of this study showed that leucocyte lysophospholipase activation was affected by the concentration of the stimulating agent and the viability of leucocytes. It is not certain if the i:icrease in lysophospholipase activity was the result of leucocyte plasma membrane alterations or to lysosomal degranulation, or if the enzymatic activity was specific for the A. suum extract. This investigation was supported by Grant #81 04-008 from the American Osteopathic Foundation.
- Published
- 1984