RESUMO
In order to investigate the phylogenetic relationships among endemic Baikal sponges of the Lubomirskiidae family and to clarify their taxonomy, the sequence variation at the silicatein-encoding gene and the mtDNA intergenic region was examined. Phylogenetic analysis of the silicatein α1 gene exonic regions in six freshwater sponge species revealed considerable interspecific variability of this region. The analysis performed did not support the monophyly of the Lubomirskia and Baikalospongia genera. The mDNA region between the COX2 and ATP6 genes was examined in five species from the Lubomirskiidae family, including multiple samples for analyzing intraspecific variations. According to the data obtained, the Baikalospongia genus was monophyletic with respect to Lubomirskia, while B. bacilifera and B. recta did not form monophyletic groups. Molecular data indicate that taxonomy of Lubomirskiidae should be revised. It was demonstrated that, in endemic Baikal sponges, the accelerated evolution was accompanied by an increase in the length of the noncoding regions in both mitochondrial and nuclear genes.
Assuntos
DNA Mitocondrial , Filogenia , Polimorfismo Genético , Poríferos/genética , Animais , Sequência de Bases , Evolução Biológica , Catepsinas/genética , Éxons , Lagos , ATPases Mitocondriais Próton-Translocadoras/genética , Dados de Sequência Molecular , Poríferos/classificação , SibériaAssuntos
Oxirredutases do Álcool/genética , Proteínas de Bactérias/genética , DNA Bacteriano/análise , Poríferos/microbiologia , Pseudomonas fluorescens/genética , Oxirredutases do Álcool/isolamento & purificação , Animais , Proteínas de Bactérias/isolamento & purificação , Sequência de Bases , Água Doce , Genoma Bacteriano/genética , Lagos/microbiologia , Sondas Moleculares , Dados de Sequência Molecular , Filogenia , Pseudomonas fluorescens/enzimologia , Alinhamento de SequênciaRESUMO
Phylogenetic analysis of the nucleotide sequences of 16S rRNA genes in the metagenomic community of Lubomirskia baicalensis has revealed taxonomic diversity of bacteria associated with the endemic freshwater sponge. Fifty-four operational taxonomic units (OTUs) belonging to six bacterial phyla (Actinobacteria, alpha-Proteobacteria, beta-Proteobacteria, Verrucomicrobia, Bacteroidetes, Cyanobacteria, and Nitrospiracea) have been identified. Actinobacteria, whose representatives are known as antibiotic producers, is the dominant phylum of the community (37%, 20 OTUs). All sequences detected shared the maximal homology with unculturable microorganisms from freshwater habitats. The wide diversity of bacteria closely coexisting with the Baikal sponge indicate the complex ecological relationships in the community formed under the unique conditions of Lake Baikal.
Assuntos
Bactérias/genética , Variação Genética , Poríferos , RNA Ribossômico 16S/genética , Animais , Bactérias/classificação , Metagenoma , Filogenia , Poríferos/genética , Poríferos/microbiologiaRESUMO
Screening of metagenomic DNA of microbial community, associated with Baikalian sponge Lubomirskia baicalensis, was made to show the presence of polyketide synthase genes (PKS). PKS enzymatic systems take part in synthesis of a great number of biologically-active substances. Cloning and sequencing of amplified products of the ketosynthase domain section of PKS gene cluster has revealed 15 fragments of PKS genes differing from each other's on 35-65% by aminoacid sequences. BLASTX analysis has shown that all these sequences belong to the KS-domains identified in various groups of microorganisms: alpha-, beta-, delta-Proteobacteria, Verrucomicrobia, Cyanobacteria, Chlorophyta. Some sequences were related to the genes which are taking part in biosynthesis of curacin A (CurI, CurJ), stigmatellin (StiC, StiG), nostophycin (NpnB), and cryptophycins (CrpB). The homology of the found sequences with those of the EMBL database varies within 50-82% confirming the presence in fresh-water sponge community the genes for synthesis of the new, yet not studied polyketide substances, possessing the biotechnological potential.
Assuntos
Bactérias/genética , Proteínas de Bactérias/genética , Clorófitas/genética , Metagenoma , Proteínas de Plantas/genética , Policetídeo Sintases/genética , Poríferos/microbiologia , Animais , Água Doce/microbiologia , Genes Bacterianos/fisiologia , Genes de Plantas/fisiologia , Filogenia , Sibéria , Microbiologia da ÁguaRESUMO
Siliceous sponge spicules contain silicateins--proteins taking part in biogenic silica precipitation and determination of the spicule morphological features. The exon-intron structure of four silicatein-alpha isoforms: -alpha1,-alpha2, -alpha3 and -alpha4 from endemic baikalian sponge Lubomirskia baicalensis was studied. For eight sponge species, including both cosmopolitan (Spongilla lacustris, Ephydatia muelleri, E. fluviatilis) and Baikal endemic (L. baicalensis, L. incrustans, Baikalospongia intermedia, B. fungiformis, Sw. papyracea) species, seventeen gene fragment sequences of different silicatein isoforms were determined. It was shown that cosmopolitan and endemic Baikalian sponges differ from each other by gene structure (have different length ofintrons). Among Baikalian sponges silicatein-alpha1 has the most variable intron length, and silicatein-alpha4 is the most conservative. Phylogenetic analysis of amino-acid silicatein sequences allow identify different silicatein isoforms, which authentically differ form four clusters on phylogenetic tree. Phylogenetic analysis of exon-intron sequences gives the possibility to separate different sponge species in the clusters.
Assuntos
Catepsinas/genética , Poríferos/genética , Animais , Evolução Molecular , Éxons/genética , Água Doce , Íntrons/genética , Filogenia , Poríferos/classificaçãoRESUMO
Morphological and molecular genetic data for freshwater sponges from the lakes of Tuva Depression, Baikalospongia dzhegatajensis (Rezvo, 1936), forms Dzh05 and Dzh06, from Chagatai Lake, as well as forms TKhl and TKh2, from the Lake Tore-Khol, were obtained and examined. In the sponges examined, which on phylogenetic tree clustered together with the Ephydatia fluviatilis (Linneaus, 1758) sponge from the family Spongillidae, the ITS rDNA regions were sequenced. Comparison of highly variable interal spacer regions of the mitochondrial genome was performed using corresponding sequences of three sponges from the family Spongillidae (E. fluviatilis, E. muelleri and Spongilla lacustris), sponges from the Chagatai and Tore-Khol lakes (Dzh06 and TKh2) with an unknown status, and sponges from the Baikalian family Lubomirskiidae. Minimum genetic differences were observed between E. fluviatilis, Dzh06, and TKh2 (from 0.003 to 0.01% of nucleotide substitutions), while maximum differences were found between the species of Lubomirskiidae and Spongillidae (from 0.928 to 2.06%). The data obtained indicated that sponges from Chagatai and Tore-Khol lakes were most close to E. fluviatilis.
Assuntos
Poríferos/genética , Animais , Sequência de Bases , Água Doce , Marcadores Genéticos , Mitocôndrias/genética , Dados de Sequência Molecular , Filogenia , RNA de Transferência de Metionina/genética , RNA de Transferência de Tirosina/genética , Sibéria , Regiões não TraduzidasRESUMO
Siliceous spicules of the freshwater Baikal sponge Lubomirskia baicalensis contain several proteins including silicateins. Existences of four different genes of silicatein alpha (alpha1, alpha2, alpha3, alpha4) which are related to silicatein alpha from the sea sponges were found when cDNA library analysis was made. The intron-exon structure of the full-size silicatein alpha1 gene was determined. This gene has total length of 1988 bp and includes 6 introns (1007 bp) and 7 exons (981 bp). With use of mass-spectrometric analysis of the spicule proteins tryptic digest, two silicateins alpha were authentically found.
