Time filter

Source Type

Shaikevich E.V.,Ni Vavilov Institute Of General Genetics | Vinogradova E.B.,Russian Academy of Sciences | Bouattour A.,Tunis el Manar University | Gouveia De Almeida A.P.,New University of Lisbon | Gouveia De Almeida A.P.,University of Pretoria
Parasites and Vectors

Background: Mosquitoes of the Culex pipiens complex are cosmopolitan, and important vectors of neglected tropical diseases, such as arbovirosis and lymphatic filariasis. Among the complex taxa, Cx. pipiens (with two forms pipiens and molestus) and Cx. quinquefasciatus are the most ubiquitous mosquitoes in temperate and tropical regions respectively. Mosquitoes of this taxa lack of morphological differences between females, but have frank behavioral and physiological differences and have different trophic preferences that influence their vectorial status. Hybridization may change the vectorial capacity of these mosquitoes, increasing vector efficiency and medical importance of resulting hybrids. Methods: Culex pipiens s.l. from 35 distinct populations were investigated by the study of mtDNA, symbiotic bacterium Wolbachia pipientis, nuclear DNA and flanking region of microsatellite CQ11 polymorphism using PCR with diagnostic primers, RFLP analysis and sequencing. Results: Six different mitochondrial haplotypes were revealed by sequencing of the cytochrome oxidase subunit I (COI) gene and three different Wolbachia (wPip) groups were identified. A strong association was observed between COI haplotypes/groups, wPip groups and taxa; haplogroup A and infection with wPipII appear to be typical for Cx. pipiens form pipiens, haplotype D and infection with wPipIV for form molestus, while haplogroup E, characteristic of Cx. quinquefasciatus, were correlated with wPipI and found in Cx. pipiens sl. from coastal regions of Southern Europe and Mediterranean region. Analysis of microsatellite locus and nuclear DNA revealed hybrids between Cx. pipiens form pipiens and form molestus, as well as between Cx. pipiens and Cx. quinquefasciatus, in Mediterranean populations, as opposed to Northern Europe. Phylogenetic analysis of COI sequences yielded a tree topology that supported the RFLP analysis with significant bootstrap values for haplotype D and haplogroup E. Conclusions: Molecular identification provides the first evidence of the presence of hybrids between Cx. quinquefasciatus and Cx. pipiens as well as cytoplasmic introgression of Cx. quinquefasciatus into Cx. pipiens as a result of hybridization events in coastal regions of Southern Europe and Mediterranean region. Together with observed hybrids between pipiens and molestus forms, these findings point to the presence of hybrids in these areas, with consequent higher potential for disease transmission. © 2016 Shaikevich et al. Source

Rippa A.,Russian National Research Medical University | Terskikh V.,Nk Koltsov Institute Of Developmental Biology | Nesterova A.,Ni Vavilov Institute Of General Genetics | Vasiliev A.,Nk Koltsov Institute Of Developmental Biology | Vorotelyak E.,Moscow State University
Histochemistry and Cell Biology

Mice with skin and hair follicle (HF) defects are common models of human skin disorders. A mutant strain with the we/we wal/wal genotype develops alopecia. We found the hair shaft structure in the pelage of mutant mice to have significant defects. Although these mice lose their hair at 21 days, a label-retaining cell population persists in HFs until at least day 54. Depilation-induced anagen was accomplished in we/we wal/wal mutants but the resulting hair shafts were short and extremely deformed. Serious abnormalities in epidermis stratification and HF morphogenesis exist in we/we wal/wal homozygous E18.5 embryos. There were significantly fewer HF primordia in this mutant compared with wild type. We discovered specific structures, identified as invalid placodes, positive for ectodysplasin A1 receptor, nuclear β-catenin, and LEF1, which failed to invaginate, produced a double basal-like layer of epidermal cells, and lacked cylindrical keratinocytes. Specification of dermal papillae (DP) was impaired, and the papillary dermis expressed alkaline phosphatase and LEF1. We also detected DP-like groups of intensively stained cells in the absence of visible signs of folliculogenesis in the epidermis. We showed differentiation disturbances in the mutant embryonic E18.5 epidermis and HFs: The cornified layer was absent, the width of the spinous layer was reduced, and HFs lacked LEF1-positive precortex cells. In this study, we used a very interesting and useful mouse model of alopecia. The presence of symptoms of skin disorders in we/we wal/wal murine embryos correlates with the postnatal skin phenotype. This correlation may help to evaluate reasons of alopecia. © 2014, Springer-Verlag Berlin Heidelberg. Source

Denisov S.V.,Russian Academy of Sciences | Bazykin G.A.,Moscow State University | Sutormin R.,Moscow State University | Favorov A.V.,Ni Vavilov Institute Of General Genetics | And 3 more authors.
Genome biology and evolution

Splice sites (SSs) are short sequences that are crucial for proper mRNA splicing in eukaryotic cells, and therefore can be expected to be shaped by strong selection. Nevertheless, in mammals and in other intron-rich organisms, many of the SSs often involve nonconsensus (Nc), rather than consensus (Cn), nucleotides, and beyond the two critical nucleotides, the SSs are not perfectly conserved between species. Here, we compare the SS sequences between primates, and between Drosophila fruit flies, to reveal the pattern of selection acting at SSs. Cn-to-Nc substitutions are less frequent, and Nc-to-Cn substitutions are more frequent, than neutrally expected, indicating, respectively, negative and positive selection. This selection is relatively weak (1 < |4Nes| < 4), and has a similar efficiency in primates and in Drosophila. Within some nucleotide positions, the positive selection in favor of Nc-to-Cn substitutions is weaker than the negative selection maintaining already established Cn nucleotides; this difference is due to site-specific negative selection favoring current Nc nucleotides. In general, however, the strength of negative selection protecting the Cn alleles is similar in magnitude to the strength of positive selection favoring replacement of Nc alleles, as expected under the simple nearly neutral turnover. In summary, although a fraction of the Nc nucleotides within SSs is maintained by selection, the abundance of deleterious nucleotides in this class suggests a substantial genome-wide drift load. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. Source

Zakharov I.,Ni Vavilov Institute Of General Genetics | Shaikevich E.,Ni Vavilov Institute Of General Genetics
European Journal of Entomology

Fifteen different mitochondrial haplotypes of the mtDNA gene COI encoding cytochrome C oxidase subunit I were identified in the 127 individuals of Adalia bipunctata studied. Two mitochondrial haplotypes, H9 and H10, differed greatly from the others. The mitochondrial polymorphism in A. bipunctata is ancient, though its age remains to be evaluated. It is shown that mitochondrial haplotypes H9 and H10 and others coexisted in the original population of A. bipunctata before it spread throughout Eurasia from Western Europe to the Baikal Area, and before the differentiation of the subspecies A. bipunctata fasciatopunctata, which differs from the European form in its elytral pattern. In order to evaluate the possible origin of the ancient mitochondrial haplotypes in the gene pool of A. bipunctata sequences of the mtDNA gene COI and of the rRNA second internal transcribed spacer of the four species of Adalia: A. bipunctata, A. decempunctata, A. frigida and A. tetraspilota, were compared. It is suggested that infection with Rickettsia had an important role in the preservation of the mitochondrial haplotypes H9 and H10 during the evolution of Adalia. Source

Moroz V.V.,Va Negovsky Research Institute Of General Reanimatology | Smelaya T.V.,Va Negovsky Research Institute Of General Reanimatology | Sal'mkova L.Ye.,Ni Vavilov Institute Of General Genetics | Golubev A.M.,Va Negovsky Research Institute Of General Reanimatology | Rubanovich A.V.,Ni Vavilov Institute Of General Genetics
Vestnik Rossiiskoi Akademii Meditsinskikh Nauk

The study included 243 patients with acute community-acquired pneumonia and 173 healthy subjects. The following candidate loci were used to investigate genetic variability: 3 sites of CYP1A1, GSTM1, GSTTl, GSTP1, ACE gene of the rennin-angiotensin system, chemokine receptor gene CCR5. Enhanced predisposition to pneumonia was shown to be characteristic of homozygotes in deletion at the ACE locus (OR=1.8;p=0.013), carriers of normal alleles of the GSTM1 locus (0R=1.7; p=0.010), and homozygotes in allele 606T of the CYPIAl gene (OR=1.6; p=0.020). Source

Discover hidden collaborations