PLA2 activity in Tetrahymena pyriformis. Effects of inhibitors and stimulators |
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| Affiliation: | 1. Department of Pathology, Faculty of Veterinary Medicine, Atatürk University, Erzurum, Turkey;2. Department of Biochemistry, Faculty of Veterinary Medicine, Atatürk University, Erzurum, Turkey;3. Department of Internal Medicine, Faculty of Veterinary Medicine, Atatürk University, Erzurum, Turkey;4. Department of Genetics, Faculty of Veterinary Medicine, Atatürk University, Erzurum, Turkey;5. German Center for Neurodegenerative Diseases, DZNE, Bonn, Germany;1. Department of Pharmacology, Faculty of Veterinary Medicine, Cairo University, 12211 Giza, Egypt;2. Department of Pathology, Faculty of Veterinary Medicine, Cairo University, 12211 Giza, Egypt;3. Department of Pharmacology, Michael Sayegh Faculty of Pharmacy, Aqaba University of Technology, Jordan;1. Physiology Department, Faculty of Medicine, Suez Canal University, Ismailia, Egypt;2. Department of Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah 27272, United Arab Emirates;3. Department of Basic Medical Sciences, College of Medicine, AlMaarefa University, Riyadh 71666, Saudi Arabia;4. Department of Anatomy, Faculty of Medicine, Mansoura University, Mansoura, Egypt;5. Pharmacology Department, Faculty of Medicine, Suez Canal University, Ismailia, Egypt;6. Forensic Medicine & Toxicology, Faculty of Veterinary Medicine, Suez Canal University, Ismailia, Egypt;7. Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Sinai University, Kantara branch, Ismailia 41636, Egypt;8. Department of Pharmacology & Toxicology, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt;9. Department of Pharmacology & Toxicology, Faculty of Pharmacy, University of Tabuk, Tabuk, Saudi Arabia;1. College of Veterinary Medicine, Northeast Agricultural University, Harbin, 150030, China;2. Suihua Food and Drug Administration, Suihua, 152000, China;1. Department of Reproduction and Artificial Insemination, Faculty of Veterinary Medicine, Ataturk University, Erzurum, Turkey;2. Department of Biochemistry, Faculty of Veterinary Medicine, Atatürk University, Erzurum, Turkey;3. Department of Department of Histology and Embryology, Faculty of Medicine, Aksaray University, Aksaray, Turkey;4. Department of Medical Biochemistry, Faculty of Medicine, Aksaray University, Aksaray, Turkey |
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| Abstract: | Phospholipase A2 (PLA2) is an enzyme which participates in signalling mechanisms cleaving arachidonate from sn-2 position of glycerophospholipids. In this study we have verified the existence of a PLA2-like activity in the free living protozoan, Tetrahymena pyriformis GL. This activity is Ca2+-independent, EDTA (10 mM) has no effect on its activity. Quinacrine (0.1 mM) and 4-bromophenacyl bromide (BPB; 0.1 mM) inhibited, melittin (20 μg/ml significantly stimulated the PLA2 activity and the release of free arachidonic acid (AA) from 1-acyl 2-14C-arachidonyl-3-phosphatidylethanolamine substrate. Melittin stimulated PLA2 hyperactivity is Ca2+-dependent. There was no considerable alteration in the PLA2 activity by stimulation of the activity by tyrosine kinase (with vanadate, H202), phospholipase C (PLC) (with phorbol 12, 13-dibutyrate) or G-proteins (with NaF, AlF4 thus in Tetrahymena PLA2 activity seems to be independent of these—in Tetrahymena (also functioning)—signalling pathways. Treatment with quinacrine and BPB leads to decreased synthesis and disturbed breakdown of phospholipids and phosphoinositides. These findings suggest that PLA2 activity is in connection with the phospholipid metabolism of Tetrahymena. |
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