RESUMEN
The psbA gene, which encodes a major photosystem II protein (protein II or D1), is a marker for the presence of phototrophic organisms in water communities. We have pioneered the use of this marker for studying the diversity of phototrophic microflora of freshwater invertebrates. The object of the study is the microbial associations accompanying the endemic Baikal sponge Baikalospongia intermedia and the surrounding aquatic microbial community. Analysis of the psbA gene sequences in the examined microbiomes demonstrates the presence of various phototrophic groups, such as Cyanobacteria, Chlorophyta, Heterokonta, Haptophyta, and Ochrophyta algae, as well as cyanophages. A total of 35 unique psbA gene sequences have been distinguished in the microbial communities of the endemic sponge B. intermedia and 32 unique sequences in the water community surrounding the sponge. These data demonstrate the involvement of sponge symbiotic communities in the accumulation of primary production and carbon cycle in the Lake Baikal ecosystem.
Asunto(s)
Ecosistema , Complejo de Proteína del Fotosistema II/genética , Filogenia , Animales , Lagos/microbiología , Poríferos/microbiologíaRESUMEN
The diversity of the symbiotic community of the endemic Baikal sponge Swartschewskia papyracea was studied, and an analysis of the polyketide synthases genes spectrum in sponge-associated microorganisms was carried out. Six bacterial phyla were detected in the S. papyracea microbiome, namely, Verrucomicrobia, Cyanobacteria, Actinobacteria, Bacteroidetes, Proteobacteria, and Planctomycetes. Unlike the microbial associations of other freshwater sponges, the community under study was dominated by the Verrucomicrobia (42.1%) and Cyanobacteria (17.5%) phyla, while the proportion of the Proteobacteria was unusually low (9.7%). In the S. papyracea community metagenome, there were identified 18 polyketide synthases genes fragments, the closest homologs of which included the polyketide synthases of the microorganisms belonging to the bacterial phyla Cyanobacteria, Proteobacteria (Betaproteobacteria, Deltaproteobacteria, and Gammaproteobacteria classes), and Acidobacteria and to the eukaryotic algae of the Heterokonta phylum (Eustigmatophyceae class). Polyketide synthase sequences from S. papyracea formed three groups on the phylogenetic tree: a group of hybrid NRPS/PKS complexes, a group of cyanobacterial polyketide synthases, and a group of homologs of the eukaryotic alga Nannochloropsis galiana. Notably, the identified polyketide synthase genes fragments showed only a 57-88% similarity to the sequences in the databases, which implies the presence of genes controlling the synthesis of the novel, still unstudied, polyketide compounds in the S. papyracea community. It was proposed that the habitation conditions of S. papyracea affect the taxonomic composition of the microorganisms associated with the sponge, including the diversity of the producers of secondary metabolites.
Asunto(s)
Microbiota/genética , Filogenia , Sintasas Poliquetidas/genética , Poríferos/microbiología , Animales , Variación Genética , Lagos , Metagenoma , Poríferos/genética , ARN Ribosómico 16S/genéticaRESUMEN
The diversity of 16S rRNA genes in the microbial community of endemic sponge Lubomirskia baicalensis with bleached patches of tissue was studied. Eight bacterial phyla were identified in the sponge microbiome: Cyanobacteria (27.3%; n = 36; 2 OTU, operational taxonomic unit), Proteobacteria (22.7%; n = 30; 5 OTU), Actinobacteria (16.7%; n = 22; 7 OTU, operation taxonomic unit), Verrucomicrobia (15.2%; n = 20; 4 OTU), Plactomycetes (9%; n = 12; 3 OTU), Bacteroidetes (4.5%; n = 6; 3 OTU), WS5 (3%; n = 4; 1 OTU), and TM7 (1.5%; n = 2; 1 OTU). The basic phyla typical of freshwater sponge microbiomes are present in the community. However, in contrast to previously studied L. baicalensis bacterial associations, a dominance of Cyanobacteria and a low number of representatives of the Bacteroidetes and Betaproteobacteria were observed in the bleached sponge community. Phylotypes exhibiting a high percentage of similarity with the microorganisms inhabiting substrates rich in organic matter were also found. Clearly, the bleaching processes of Baikal sponges affect the composition and the ratio of the major taxonomic groups of sponge-associated bacteria.
Asunto(s)
Bacterias/clasificación , Bacterias/genética , Poríferos/microbiología , ARN Bacteriano/genética , ARN Ribosómico 16S/genética , Simbiosis/fisiología , AnimalesRESUMEN
The diversity of bacteria associated with deep-water sponge Baikalospongia intermedia was evaluated by sequence analysis of 16S rRNA genes from two sponge samples collected in Lake Baikal from depths of 550 and 1204 m. A total of 64 operational taxonomic units, belonging to nine bacterial phyla, Proteobacteria (classes Alphaproteobacteria,. Betaproteobacteria, Gammaproteobacteria, and Deltaproteobacteria), Actinobacteria, Planctomycetes, Cloroflexi, Verrucomicrobia, Acidobacteria, Chlorobi, and Nitrospirae, including candidate phylum WS5, were identified. Phylogenetic analysis showed that the examined communities contained phylotypes exhibiting homology to uncultured bacteria from different lake ecosystems, freshwater sediments, soil and geological formations. Moreover, a number of phylotypes were relative to psychrophilic, methane-oxidizing, sulfate-reducing bacteria, and to microorganisms resistant to the influence of heavy metals. It seems likely that the unusual habitation conditions of deep-water sponges contribute to the taxonomic diversity of associated bacteria and have an influence on the presence of functionally important microorganisms in bacterial communities.
Asunto(s)
Microbiota , Filogenia , Poríferos/microbiología , Animales , Bacterias/genética , Bacterias/aislamiento & purificaciónRESUMEN
The metabolic test with antipyrine was performed, the relationship between genotypes of GSTT1 and GSTM1 polymorphisms were studied, and cotinine level was measured in 116 men chronically exposed to mercury. The individuals were divided in 4 groups depending on the diagnosis of chronic mercury intoxication. The changes in the parameters of antipyrine test were studied in linked samples (N=62, 4 year interval); in patients with chronic mercury intoxication, the disease stage was taken into account. Inhibition of antipyrine metabolism, increased frequency of combination of GSTT1(0/0)/GSTM1(+) genotypes in patients with chronic mercury intoxication, and the specificity of cytochrome P450 inhibition with mercury suggest that disease progression is related to inhibition of cytochrome P450 isoforms in the brain that catalyze regulation of endogenous substrates.
Asunto(s)
Sistema Enzimático del Citocromo P-450/metabolismo , Glutatión Transferasa/genética , Intoxicación del Sistema Nervioso por Mercurio/enzimología , Mercurio/toxicidad , Enfermedades Profesionales/enzimología , Antipirina/metabolismo , Encefalopatías/inducido químicamente , Encefalopatías/enzimología , Estudios de Asociación Genética , Genotipo , Glutatión Transferasa/metabolismo , Humanos , Masculino , Enfermedades Profesionales/inducido químicamente , Exposición Profesional , Polimorfismo GenéticoRESUMEN
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.
Asunto(s)
ADN Mitocondrial , Filogenia , Polimorfismo Genético , Poríferos/genética , Animales , Secuencia de Bases , Evolución Biológica , Catepsinas/genética , Exones , Lagos , ATPasas de Translocación de Protón Mitocondriales/genética , Datos de Secuencia Molecular , Poríferos/clasificación , SiberiaRESUMEN
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.
Asunto(s)
Bacterias/genética , Variación Genética , Poríferos , ARN Ribosómico 16S/genética , Animales , Bacterias/clasificación , Metagenoma , Filogenia , Poríferos/genética , Poríferos/microbiologíaRESUMEN
The relationship between blood levels of HSP72, HSP72+HSP73, and HSP90 and genotypes of three polymorphisms of the HSP70 family, HSPA1L (2437T/C) and HSPA1B (2074G/C and 1267A/G) as well as GSTT1 and GSTM1 polymorphisms was studied in 82 men chronically exposed to mercury. Of these, 40 men were exposed to mercury for more than 10 years (group 1) and 42 developed chronic mercuric intoxication (group 2). The groups differed significantly by TT (p=0.004) and TC (p=0.007) genotypes of HSPA1L gene locus 2437T/C. Differences in the heat shock protein content associated with HSP70 gene polymorphism were detected only for HSPA1B gene locus 2074G/C and consisted in reduction of HSP90 (p=0.020) and HSP72 (p=0.056) for GG genotype in group 2 in comparison with group 1. Combination of GSTT1(+)/GSTM1(0/0) genotypes was associated with reduction of the protein levels, while variants including GSTT1(0/0) were associated with a significant elevation thereof.
Asunto(s)
Glutatión Transferasa/genética , Proteínas HSP70 de Choque Térmico/sangre , Proteínas HSP90 de Choque Térmico/sangre , Mercurio/toxicidad , Exposición a Riesgos Ambientales , Genotipo , Proteínas HSP70 de Choque Térmico/genética , Proteínas HSP90 de Choque Térmico/genética , Humanos , Masculino , Intoxicación por Mercurio/sangre , Intoxicación por Mercurio/genética , Persona de Mediana Edad , Polimorfismo de Nucleótido SimpleRESUMEN
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.
Asunto(s)
Catepsinas/genética , Poríferos/genética , Animales , Evolución Molecular , Exones/genética , Agua Dulce , Intrones/genética , Filogenia , Poríferos/clasificaciónRESUMEN
The distribution of two CYP1A2 gene polymorphisms, CYP1A2*F and CYP1A2*D, was studied in a group of 38 men. Antipyrine elimination test was carried out and urinary cotinine was measured. The contribution of these CYP1A2 gene polymorphisms, age, and tobacco smoking to accumulation of three main antipyrine metabolites in the urine was evaluated by regression analysis. The impact of both studied polymorphisms was essential for urinary levels of 3-hydroxymethylantipyrine (metabolite most dependent on cytochrome P-4501A2) and hence, for functional activity of this isoform of the enzyme.
Asunto(s)
Antipirina/metabolismo , Citocromo P-450 CYP1A2/genética , Polimorfismo Genético , Adulto , Secuencia de Bases , Cartilla de ADN , Humanos , Masculino , Persona de Mediana EdadRESUMEN
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.