How Drosophila species acquire cold tolerance--qualitative changes of phospholipids.

摘要: Phospholipids of many cold-tolerant organisms have been reported to contain more unsaturated fatty acids than cold-susceptible organisms, a phenomenon known maintain membrane fluidity at low temperature. However, we obtained results the contrary through comparison phospholipids six temperate and subtropical species belonging Drosophila melanogaster group. With enhancement cold tolerance, percentages monoenoic increased but dienoic decreased, that is, number double bonds in phospholipid decreased without marked variation acids. Concomitantly, percentage containing 16 carbon atoms increased, while with 18 decreased. Since phosphatidylethanolamine is dominant Drosophila, these changes probably contribute keeping homeoviscosity cellular membranes manner different phosphatidylcholine-rich membranes, thereby increasing tolerance.