RESUMO
The ability to grow by anaerobic CO oxidation with production of H2 from water is known for some thermophilic bacteria, most of which belong to Firmicutes, as well as for a few hyperthermophilic Euryarchaeota isolated from deep-sea hydrothermal habitats. A hyperthermophilic, neutrophilic, anaerobic filamentous archaeon strain 1505=VKM B-3180=KCTC 15798 was isolated from a terrestrial hot spring in Kamchatka (Russia) in the presence of 30% CO in the gas phase. Strain 1505 could grow lithotrophically using carbon monoxide as the energy source with the production of hydrogen according to the equation CO+H2OâCO2+H2; mixotrophically on CO plus glucose; and organotrophically on peptone, yeast extract, glucose, sucrose, or Avicel. The genome of strain 1505 was sequenced and assembled into a single chromosome. Based on 16S rRNA gene sequence analysis and in silico genome-genome hybridization, this organism was shown to be closely related to the Thermofilum adornatum species. In the genome of Thermofilum sp. strain 1505, a gene cluster (TCARB_0867-TCARB_0879) was found that included genes of anaerobic (Ni,Fe-containing) carbon monoxide dehydrogenase and genes of energy-converting hydrogenase ([Ni,Fe]-CODH-ECH gene cluster). Compared to the [Ni,Fe]-CODH-ECH gene clusters occurring in the sequenced genomes of other H2-producing carboxydotrophs, the [Ni,Fe]-CODH-ECH gene cluster of Thermofilum sp. strain 1505 presented a novel type of gene organization. The results of the study provided the first evidence of anaerobic CO oxidation coupled with H2 production performed by a crenarchaeon, as well as the first documented case of lithotrophic growth of a Thermofilaceae representative.
Assuntos
Monóxido de Carbono/metabolismo , Hidrogênio/metabolismo , Thermofilaceae/crescimento & desenvolvimento , Thermofilaceae/metabolismo , Aldeído Oxirredutases/genética , Anaerobiose , Processos Autotróficos , Proteínas de Bactérias/genética , DNA Bacteriano/genética , Genoma Bacteriano/genética , Fontes Termais/química , Fontes Termais/microbiologia , Hidrogenase/genética , Complexos Multienzimáticos/genética , Família Multigênica , Oxirredução , Filogenia , RNA Ribossômico 16S/genética , Federação Russa , Análise de Sequência de DNA , Thermofilaceae/classificação , Thermofilaceae/genéticaRESUMO
Tuberculosis caused by multidrug-resistant (MDR) and extensively drug-resistant (XDR) Mycobacterium tuberculosis (MTB) strains is a growing problem in many countries. The availability of the complete nucleotide sequences of several MTB genomes allows to use the comparative genomics as a tool to study the relationships of strains and differences in their evolutionary history including acquisition of drug-resistance. In our work, we sequenced three genomes of Russian MTB strains of different phenotypes--drug susceptible, MDR and XDR. Of them, MDR and XDR strains were collected in Tomsk (Siberia, Russia) during the local TB outbreak in 1998-1999 and belonged to rare KQ and KY families in accordance with IS6110 typing, which are considered endemic for Russia. Based on phylogenetic analysis, our isolates belonged to different genetic families, Beijing, Ural and LAM, which made the direct comparison of their genomes impossible. For this reason we performed their comparison in the broader context of all M. tuberculosis genomes available in GenBank. The list of unique individual non-synonymous SNPs for each sequenced isolate was formed by comparison with all SNPs detected within the same phylogenetic group. For further functional analysis, all proteins with unique SNPs were ascribed to 20 different functional classes based on Clusters of Orthologous Groups (COG). We have confirmed drug resistant status of our isolates that harbored almost all known drug-resistance associated mutations. Unique SNPs of an XDR isolate CTRI-4(XDR), belonging to a Beijing family were compared in more detail with SNPs of additional 14 Russian XDR strains of the same family. Only type specific mutations in genes of repair, replication and recombination system (COG category L) were found common within this group. Probably the other unique SNPs discovered in CTRI-4(XDR) may have an important role in adaptation of this microorganism to its surrounding and in escape from antituberculosis drugs treatment.
Assuntos
Tuberculose Extensivamente Resistente a Medicamentos/genética , Tuberculose Extensivamente Resistente a Medicamentos/microbiologia , Mycobacterium tuberculosis/classificação , Mycobacterium tuberculosis/genética , Antituberculosos/farmacologia , Hibridização Genômica Comparativa , DNA Bacteriano , Tuberculose Extensivamente Resistente a Medicamentos/epidemiologia , Genoma Bacteriano/efeitos dos fármacos , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Mycobacterium tuberculosis/isolamento & purificação , Fenótipo , Filogenia , Federação Russa , SibériaRESUMO
Potato (Solanum tuberosum L.) is the world's most important non-grain food crop and is central to global food security. It is clonally propagated, highly heterozygous, autotetraploid, and suffers acute inbreeding depression. Here we use a homozygous doubled-monoploid potato clone to sequence and assemble 86% of the 844-megabase genome. We predict 39,031 protein-coding genes and present evidence for at least two genome duplication events indicative of a palaeopolyploid origin. As the first genome sequence of an asterid, the potato genome reveals 2,642 genes specific to this large angiosperm clade. We also sequenced a heterozygous diploid clone and show that gene presence/absence variants and other potentially deleterious mutations occur frequently and are a likely cause of inbreeding depression. Gene family expansion, tissue-specific expression and recruitment of genes to new pathways contributed to the evolution of tuber development. The potato genome sequence provides a platform for genetic improvement of this vital crop.
