Familial hypercholesterolemia in St. Petersburg: Diversity of mutations argues against a strong founder effect

Examination of low-density lipoprotein (LDL) receptor gene, its promoter, and most of exon-intron boundaries from 74 probands with familial hypercholesterolemia (FH) of St. Petersburg revealed 34 mutations and 8 widely spread polymorphisms at this locus. Only four mutations were considered neutral, while the other 30 are likely to cause familial hypercholesterolemia (FH). Mutations in the LDL receptor gene, causing the disease, were identified in 41 (55%) out of 74 families with FH. Mutation R3500Q in apolipoprotein B (APOB) gene was not detected in all probands. Therefore in the families lacking mutations hypercholesterolemia was caused by mutations in the introns of the LDL receptor gene or by other genetic factors. Nineteen mutations causing disease progression were described in St. Petersburg for the first time, while 18 of them are specific for Russia. Among Ashkenazi Jews, predominant mutation G197del was detected in 30% (7 out of 22) of patients with FH. In the Slavic population of St. Petersburg, no predominant mutations were detected. Only five mutations were identified in two Slavic families, while 24 were found in unique families. These data are indicative of the lack of a strong founder effect for FH in the St. Petersburg population.     

New ceramides from sea sponge Oceanapia sp

Total ceramides containing nonbranched and iso-branched C18- and C19-phytosphingosines acylated with non-hydroxylated fatty acids were isolated from a marine sponge Oceanapia sp. The structures of these compounds were determined by HPLC, NMR, MALDI-TOF MS, and GLC-MS of the Me3Si derivatives and by chemical transformations. The English version of the paper: Russian Journal of Bioorganic Chemistry, 2006, vol. 32, no. 3; see also http://www.maik.ru.     

A polymer with a backbone of 3-deoxy-D-glycero-D-galacto-non-2-ulopyranosonic acid, a teichuronic acid, and a beta-glucosylated ribitol teichoic acid in the cell wall of plant pathogenic Streptomyces sp. VKM Ac-2124.

Structures of cell wall anionic polymers of the strain Streptomyces sp. VKM Ac-2124, a causative agent of potato scab, which is phylogenetically the closest to plant pathogenic species S. setonii and S. caviscabies, were studied. The strain contains three anionic glycopolymers, viz., a teichuronic acid with a disaccharide repeating unit -->6)-alpha-d-Glcp-(1-->4)-beta-d-ManpNAc3NAcA-(1-->, a beta-glucosylated polymer of 3-deoxy-d-glycero-d-galacto-non-2-ulopyranosonic acid (Kdn), and a beta-glucosylated 1,5-poly(ribitol phosphate). The strain studied is the second representative of plant pathogenic streptomycetes inducing potato scab disease, the cell wall anionic polymers of which were shown to contain a Kdn-polymer. Presumably, the presence of Kdn-containing structures in the surface regions of pathogens is essential for their efficient attachment to host plant cells.     

Poly(ADP-ribosylation) of proteins determines the pool of endogenous NAD and the radiosensitivity of thymus lymphocytes

A decrease in the endogenous NAD content that occurs immediately after gamma-irradiation of thymus lymphocytes is attributed to activation of poly (ADP-ribosylation) and not to changes in the activity of NAD-glycohydrolase and/or to the release of NAD from cells. The addition of benzamide 60 min before irradiation prevents the postirradiation drop of the NAD level and produces a radioprotective effect. At the same time, benzamide inhibits nuclear superhelix DNA repair and causes an average of 40 per cent decrease in the activity of DNA ligases I and II. The authors discuss the idea that the content of intracellular NAD in thymocytes is a critical factor responsible for the vitality of these cells.     

Regulation of LacZ mRNA translatability in a cell-free system at heat shock by the last four sense codons

Under heat shock conditions translation of Xenopus laevis normal mRNAs in a rabbit reticulocyte cell-free system is blocked whereas hsp70 mRNA is translated. mRNA for E. coli beta-galactosidase containing the last four sense codons of Drosophila hsp70 at its 3'-end was constructed. This mRNA is efficiently translated in a rabbit reticulocyte cell-free system at 43 degrees C.     

Energetic aspects of CO oxidation in desulfovibrio desulfuricans

In cell suspension of Desulfovibrio desulfuricans B-1388, oxidation of CO as the only energy source is associated with reduction of SO42-. After a 2-h incubation of cells in 8% CO, 81% of the gas is converted. Oxidation of 1 mole CO results in formation of 0.23 mole H2S. Intracellular ATP content increases from 2.5 (control) to 8.3 nmoles/mg (during CO conversion). Dinitrophenol inhibits sulfate reduction and CO oxidation. CO dehydrogenase was detected in cytoplasmic and membrane cell fractions (59 and 34%, respectively).     

Effects of prolactin on intracellular stored calcium in the course of bovine oocyte maturation in vitro

At present there are divergent opinions as to the role of prolactin (PRL) in the mechanisms of meiotic regulation in mammals. We investigated the effects of bovine PRL (bPRL) on bovine oocyte maturation in different culture systems and varying levels of intracellular stored calcium ([Ca2+]is) in the oocytes. Cumulus-oocyte complexes (COC) were incubated in TCM 199 containing either 10% fetal calf serum (FCS) in the absence (System 1) or presence (System 2) of FSH and estradiol, or 6 mg/mL bovine serum albumin (BSA) in the presence of FSH and estradiol (System 3). Levels of [Ca2+]is in oocytes were determined by using the fluorophore chlortetracycline. The addition of 50 ng/mL bPRL to different culture media increased the percentage of oocytes at telophase I and metaphase II stages (Systems 1 and 2) and/or decreased the percentage of oocytes with degenerated chromosomes (Systems 1 and 3). Compared with the control, lower levels of [Ca2+]is were observed in oocytes cultured for 2.5 h in those systems in which bPRL decreased the rate of oocytes with degenerated chromosomes (1.27+/-0.11 vs. 1.67+/-0.09 arbitrary units (AU) in System 1, P<0.001 and 1.27+/-0.12 vs. 1.52+/-0.04 AU in System 3, P<0.001). These findings show that the effects of bPRL on bovine oocyte maturation depend on the composition of the culture system and that the decline in the rate of oocytes with degenerated chromosomes in response to bPRL may be the result of the decrease in [Ca2+ ]is levels at early stages of oocyte maturation.