STUDIES ON THERMAL ADAPTATION IN TETRAHYMENA MEMBRANE-LIPIDS - MODIFICATION OF POSITIONAL DISTRIBUTION OF PHOSPHOLIPID ACYL CHAINS IN PLASMA-MEMBRANES, MITOCHONDRIA AND MICROSOMES

  • 1 January 1982
    • journal article
    • research article
    • Vol. 711  (2) , 229-244
Abstract
The positional distribution of fatty acyl chains in major glycerophospholipids (phosphatidylethanolamine, phosphatidylcholine and 2-aminoethylphosphonolipid) of 3 membrane fractions (plasma membranes, mitochondria and microsomes) of the thermotolerant T. pyriformis NT-1 cells was analyzed at various time intervals within 10 h after a temperature shift from 39-15.degree. C. During this period of acclimation there were no changes in the total phospholipid content and its proportional composition. At the 1-position, the content of palmitate in phosphatidylethanolamine (present solely in diacyl type), diacylphosphatidylcholine and diacyl-(2-aminoethyl)phosphonolipid was decreased progressively after temperature-shift; .gamma.-linolenate increased in a complementary fashion, in mitochondria and microsomes. The increase in the percentage of linoleate was compensated by the decrease in oleate at the 2-position of two 1,2-diacylphospholipids. As for 1-alkyl-2-acyl-phospholipids, a marked increment in .gamma.-linolenate occurred, with a decline of oleate and linoleate at the 2-position of 1-alkyl-2-acyl-phosphatidylcholine, but no significant alterations were seen at the 2-position of 1-alkyl-2-acyl-(2-aminoethyl)phosphonolipid. The newly modified phospholipid molecular species such as 1-.gamma.-linolenoyl-2-linoleoyl-phosphatidylethanolamine and 1-hexadecyl-2-.gamma.-linolenoyl-phosphatidylcholine disseminate rapidly to other cell compartments and they would play a pivotal role in the adaptive amelioration of altered membrane physical states during the cold acclimation.

This publication has 3 references indexed in Scilit: