A glyceryl ether containing phosphoglyceride, 1-O-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine (Ac-GEPC), has been shown to have a biological activity indistinguishable from that of naturally generated (rabbit) platelet activating factor (PAF). Its biochemical and biological properties so closely parallel those of naturally occurring PAF that we propose they are one and the same compound. Both PAF and AcGEPC could be converted to an inactive form through base-catalyzed methanolysis and restored to 100% functional activity by reaction with acetic anhydride. The synthetic lipid, AcGEPC, elicited 50% secretion of serotonin from rabbit platelets at a level of 10(-10) M (based on phosphorus). A propionyl derivative had somewhat comparable activity towards platelets, whereas the butyryl homologue was some 7-fold less active and the stearoyl derivative was inactive. These short chain acylglyceryl ether phosphoglycerides represent an entirely new, potent and unique class of lipid chemical mediators. 1-Acyl-2-acetyl-sn-glyceryl-3-phosphorylcholine (AcLL) also exhibited activity towards platelets but was some 200-fold less active than AcGepc. the propionyl lysolecithin behaved quite similarly to AcLL, but butyryl and stearoyl lysolecithins showed no activity. 相似文献
The total lipids of Pinus halepensis pollen were separated into individual classes of neutral and polar lipids and the components of each class were identified and determined quantitatively. Free fatty acids, waxes and triacylglycerols were found as the main constituents of neutral lipids and phosphatidylcholine and phosphatidylethanolamine of polar lipids. Glycerylether derivatives were detected in neutral and polar lipid fractions. Free and esterified volatile fatty acids were also found in pollen and its neutral lipid fraction. 相似文献
Adriamycin semiquinone radicals are spontaneously generated by adriamycin solutions at physiologic pH. Rate of radical formation and equilibrium-state radical yield increase with increasing pH from 7.4 to 8.85. The radicals are oxygen sensitive, but the mechanism of radical formation is oxygen independent and associated with proton removal from the dihydroquinone of adriamycin. The less cardiotoxic and non-mutagenic (Ames test) anthracycline 5-iminodaunorubicin does not form semiquinone radicals spontaneously at physiologic pH. 相似文献
1. The effect of two homo-aza-steroidal esters with antineoplastic activity, namely 3 beta-hydroxy-13 alpha-amino-13,17-seco-5 alpha-androstan-17-oic-13,17-lactam-p-bis(2-chloroethyl)aminoph enoxyacetate (NSC 294859) and 3 beta-hydroxy-13 alpha-amino-13,17-seco-5 alpha-androstan-17-oic-13,17-lactam-p-bis(2-chloroethyl)aminoph enylacetate (ASE) on protein synthesis rate was studied in ovaries of Drosophila melanogaster females. 2. Two different concentrations for each compound were examined. 3. Both esters containing the same alkylating agent have been shown to decrease protein synthesis in relation to control. 相似文献
The rapid DNA sequencing system based on the single-stranded bacteriophage M13 and the chain-terminator method has been used to look directly for mutational alterations. A small DNA fragment that primes DNA synthesis through the N-terminal 200 base pairs of the beta-galactosidase gene was prepared, and used to detect changes in base sequence among phages that give white plaques after treatment of the host cells with bleomycin. Bleomycin treatment of E. coli in which M13 mp2 was growing gave an increase in white plaque frequency. DNA sequence analysis of phage from 7 independent mutant plaques showed them all to have a frameshift mutation. 相似文献