Yeast comparative genetics. A new MEL15 alpha-galactosidase gene of Saccharomyces cerevisiae

To supplement the earlier identified European family of the highly homologous alpha-galactosidase MEL1-MEL11 genes and the African family of the divergent MEL12-MEL14 genes, a new MEL gene (MEL15) was found in several Saccharomyces cerevisiae strains isolated from maize dough in Ghana. Southern blotting and restriction enzyme analysis assigned the MEL15 gene to the African family and mapped it to chromosomes IV/XII, which migrate together in electrophoresis. Tetrad analysis ruled out the MEL15 location in the left arm of chromosome IV or the right arm of chromosome XII, which respectively contain the known MEL5 and MEL10 genes.     

Diversity and ecology of algae from the Nahal Qishon river,northern Israel

In 59 samples of periphyton and phytoplankton collected in 2002 - 2003 from the Nahal Qishon (Qishon River), northern Israel, we found 178 species from seven divisions of algae and cyanoprocaryotes. Diatoms, clorophytes, and cyanoprocaryotes prevail. Nitzschia and Navicula (Bacillariophyta) are the most abundant. Most of the species are cosmopolitan or widespread, except Lagynion janei (Chrysophyta), which is endemic for the Mediterranean Realm. About 17% of species (26) are new for Israel and five of them represent the first recorded genera: Crinalium endophyticum Crow, Actinocyclus normanii (Gregory) Hustedt, Rhizoclonium hieroglyphicum (Agardh) Kütz (Chlorophyta), Lagynion janei Bourelly, and Stylococcus aureus Chodat. Most of them come from a rare riverine assemblage with red alga Audouinella pygmea, as well as from the estuarine assemblage. Alkaliphiles predominate among the indicators of acidity, with few acidophiles confined to the communities under the impact of industrial wastes. Among the indicators of salinity, most numerous are the oligohalobien-indifferents and species adapted to a moderate salinity level. The relative species richness of ecological groups and the indices of saprobity are correlated with changes in conductivity, pH, and N-nitrate concentration. Indicators of organic pollution fall in the range of betameso- to alfamesosaprobic self-purification grades. Our studies show ecological significance of the Nahal Qishon as a model for a strongly disturbed aquatic ecosystem in the coastal zone of eastern Mediterranean.     

Molecular polymorphism of α-galactosidase <Emphasis Type="Italic">MEL</Emphasis> genes of <Emphasis Type="Italic">Saccharomyces</Emphasis> yeasts

Molecular genetic analysis of melibiose-fermenting Saccharomyces strains isolated from fermentative processes and natural sources in different world regions was conducted to deduce the evolutionary diversity of Saccharomyces yeasts and find new α-galactosidase MEL genes. The species S. bayanus, S. mikatae, and S. paradoxus were shown to have a single copy of MEL and not accumulate polymeric genes, unlike some S. cerevisiae populations. The polymeric genes MELp1 and MELp2 were identified in S. paradoxus for the first time. Genes identical by 98.7% are located on the chromosomes X and VI, respectively. Phylogenetic analysis indicates that MEL genes of the Saccharomyces yeasts are species-specific.     

GAP-43 regulates NCAM-180-mediated neurite outgrowth

The neural cell adhesion molecule (NCAM), and the growth-associated protein (GAP-43), play pivotal roles in neuronal development and plasticity and possess interdependent functions. However, the mechanisms underlying the functional association of GAP-43 and NCAM have not been elucidated. In this study we show that (over)expression of GAP-43 in PC12E2 cells and hippocampal neurons strongly potentiates neurite extension, both in the absence and in the presence of homophilic NCAM binding. This potentiation is crucially dependent on the membrane association of GAP-43. We demonstrate that phosphorylation of GAP-43 by protein kinase C (PKC) as well as by casein kinase II (CKII) is important for the NCAM-induced neurite outgrowth. Moreover, our results indicate that in the presence of GAP-43, NCAM-induced neurite outgrowth requires functional association of NCAM-180/spectrin/GAP-43, whereas in the absence of GAP-43, the NCAM-140/non-receptor tyrosine kinase (Fyn)-associated signaling pathway is pivotal. Thus, expression of GAP-43 presumably acts as a functional switch for NCAM-180-induced signaling. This suggests that under physiological conditions, spatial and/or temporal changes of the localization of GAP-43 and NCAM on the cell membrane may determine the predominant signaling mechanism triggered by homophilic NCAM binding: NCAM-180/spectrin-mediated modulation of the actin cytoskeleton, NCAM-140-mediated activation of Fyn, or both.     

Peptide derivatives of tylosin-related macrolides

Approaches to the synthesis of model compounds based on the tylosin-related macrolides desmycosin and O-mycaminosyltylonolide were developed using specially designed peptide derivatives of macrolide antibiotics to study the conformation and topography of the nascent peptide chain in the ribosome tunnel. A method for selective bromoacetylation of desmycosin at the hydroxyl group of mycinose was developed, which involves preliminary acetylation of mycaminose. The reaction of the 4"-bromoacetyl derivative of the antibiotic with cesium salts of the dipeptide Boc-Ala-Ala-OH and the hexapeptide MeOTr-Gly-Pro-Gly-Pro-Gly-Pro-OH led to the corresponding peptide derivatives of desmycosin. The protected peptides Boc-Ala-Ala-OH, Boc-Ala-Ala-Phe-OH, and Boc-Gly-Pro-Gly-Pro-Gly-Pro-OH were condensed with the C23-hydroxyl group of O-mycaminosyltylonolide.     

Phylogeographic Analysis of Mitochondrial DNA in the Nogays: A Strong Mixture of Maternal Lineages from Eastern and Western Eurasia

Analysis of mtDNA markers in a population of the Nogays (n = 206), the people inhabiting the North Caucasus and speaking a Turkic language of the Altaic linguistic family, has revealed a high level of genetic diversity (H = 0.99). The identified haplotypes include all major West Eurasian haplogroups, with the prevalence of H and U clusters (22 and 21%, respectively), but the percentage of lineages specific for East Eurasian populations is the highest (40%). Some other mtDNA variants in the Nogay population belong to the M1 haplogroups typical of northeastern Africa and U2 characteristic of Indian populations. Thus, components of different origin have contributed to the gene pool of Nogays. An erratum to this article is available at .     

Analysis of the VNTR Polymorphism at the PAH and eNOS Genes and the CCR5 Gene Deletion in Populations of Northern Caucasus

VNTR allelic polymorphism at the phenylalanine hydroxilase (PAH) and endothelial constitutive nitric oxide synthase (eNOS) genes and the prevalence of the CCR5 chemokine receptor gene 32-bp deletion were examined in four populations of Northern Caucasus: Adygs, Kumyks, Karachais, and Nogais (Kuban and Karanogais). Population-specific features of the allele and genotype frequency distribution patterns of the polymorphisms examined were described. The data obtained were compared to those obtained from literature. The results of the study confirmed that the frequency and occurrence of the PAH polymorphic alleles exhibit substantial interpopulation differences. In the populations of Northern Caucasus, the eNOS minisatellite polymorphism alleles and genotypes frequency distribution patterns were close to those described earlier for populations of the Volga–Ural region (VUR), and also for the Australian Caucasoids, Japanese, and Turks. In the populations examined, the mean frequency of the CCR5 gene deletion was 0.055, which was somewhat lower than in the populations of VUR (0.070) and Europe (0.081), and practically identical to that in Asian populations (0.050). For each population observed and expected heterozygosities at each locus were calculated. In general, the gene pool of Northern Caucasian populations showed substantial differentiation at the loci examined: the G _ST value was 0.0274. The data for individual loci showed that the greater contribution to the interpopulation diversity was made by the differences in the PAH VNTR allele frequencies (G _ST = 0.04), while the differences at the eNOSand CCR5 loci were small (G _ST = 0.0025 and G _ST = 0.0039, respectively).