[Molecular phylogenetic analysis of the ant genus Formica L. (Hymenoptera: Formicidae) from Palearctic region].

Sixty-five sequences of the mitochondrial DNA cytochrome b gene fragment (759 bp) and 23 sequences of the NADH dehydrogenase subunit 6 gene fragment (224 bp) were compared in ants of the genus Formica L. from different regions of the Palearctic and in Polyergus rufescens Latr. as outgroup. In total, 28 species of the genus Formica were examined. As a result, dated trees with a molecular clock were constructed showing the phylogenetic relationships of Formica ants. The topology of the obtained tree based on the Cyt-b sequences was found to be not consistent with the generally accepted opinion on the Formica rufa and F. rufibarbis groups. New data on the formation history of the present-day fauna of Formica ants of the Palearctic were obtained. It was demonstrated that a considerable fraction of the examined species (about a third) were formed in the Quaternary Period.

[Probucol and alpha-tocopherol stimulate the synthesis of bile acids in cultured rabbit hepatocytes]. / Probukol i alpha-tokoferol stimuliruiut sintez zhelchnykh kislot v kul'tiviruemykh gepatotsitakh krolika.

Primary cultures of rabbit hepatocytes were used to examine the effect of probucol and alpha-tocopherol on cholesterol and bile acid metabolism. After 24-hour preincubation of cells with 100 microM probucol, the cholesterol and cholesteryl ester content increased--by 30% and 50%, respectively. This was accompanied by decreasing incorporation of [14C]acetate into cholesterol (down to 25-35%). At the same time, alpha-tocopherol had no effect on cholesterol accumulation in hepatocytes, while cholesterol synthesis was stimulated by 30-50%. Addition of 100 microM probucol or alpha-tocopherol to a culture medium containing 10% fetal calf serum and [14C]cholesterol caused a significant (30-40%) stimulation of bile acid synthesis. Stimulation by probucol was dependent on the presence of exogenous plasma or HDL2 cholesterol, while alpha-tocopherol enhanced this process in a cholesterol-free medium. Stimulation (40%) of bile acid secretion by probucol in the presence of physiological concentrations of apo E-free HDL2 was found. Study of receptor-mediated uptake of HDL2 revealed that: (i) probucol stimulated apo E secretion; (ii) HDL2 isolated from a medium of probucol-treated cells contained 2-3 times more apo E than the particles preincubated with cells without the drug; (iii) apo E-enriched HDL2 particles were incorporated into cultured human skin fibroblasts 1.5-3.0 times more effectively than apo E depleted HDL2; (iv) monoclonal antibody against the LDL-receptor binding domain of apo E effectively (by 40%) inhibited the apo E-enriched HDL2 uptake.(ABSTRACT TRUNCATED AT 250 WORDS)