Comparative biochemical study of brain phospholipids in insects

Studies have been made on the content of total phospholipids (PL) and their separate families in the brain of larvae and imago of the insect species Blaberus giganteus, Periplaneta americana, Tenebrio molitor and Barathra brassicae. It was shown that during larval-pupal-imaginal transformation in T. molitor and B. brassicae the content of total PL increases by 17 and 14% respectively, whereas in B. giganteus and P. americana PL concentration undergoes only insignificant changes. With respect to total PL content the species investigated form the following sequence: B. brassicae greater than T. molitor greater than P. americana greater than B. giganteus. In larval and imago forms of these insects phosphatidylethanolamine, phosphatidylcholine, phosphatidylserine, phosphatidylinositol, sphingomyelin and polyglycerophosphatide were found in the brain. Besides, in the brain of B. giganteus and P. americana lysophosphatidylethanolamine and in the brain of T. molitor -- phosphatidic acid are present. Qualitative PL composition in larval and imago forms is identical, while quantitative ratio of separate fractions differs insignificantly. In all the species investigated, phosphatidylethanolamine and phosphatidylcholine are the most abundant phospholipids.