RESUMO
The conjunctival sac of healthy human harbours a variety of microorganisms. When the eye is compromised, an occasional inadvertent spread happens to the adjacent tissue, resulting in bacterial ocular infections. Microbiological investigation of the conjunctival swab is one of the broadly used modality to study the aetiological agent of conjunctiva. However, most of the time such methods yield unsatisfactory results. Hence, the present study intends to identify the bacterial community in human conjunctiva of pre-operative subjects through 16S rRNA gene libraries. Out of 45 samples collected from preoperative patients undergoing cataract surgery, 36 libraries were constructed with bacterial nested-PCR-positive samples. The representative clones with unique restriction pattern were generated through Amplified Ribosomal DNA Restriction Analysis (ARDRA) which were sequenced for phylogenetic affiliation. A total of 211 representative clones were obtained which were distributed in phyla Actinobacteria, Firmicutes, α-Proteobacteria, ß-Proteobacteria, γ-Proteobacteria, Bacteroidetes, and Deinococcus-Thermus. Findings revealed the presence of polybacterial community, especially in some cases even though no bacterium or a single bacterium alone was identified through cultivable method. Remarkably, we identified 17 species which have never been reported in any ocular infections. The sequencing data reported 6 unidentified bacteria suggesting the possibility of novel organisms in the sample. Since, polybacterial community has been identified consisting of both gram positive and gram negative bacteria, a broad spectrum antibiotic therapy is advisable to the patients who are undergoing cataract surgery. Consolidated effort would significantly improve a clear understanding of the nature of microbial community in the human conjunctiva which will promote administration of appropriate antibiotic regimen and also help in the development of oligonucleotide probes to screen the predominant pathogens for early predisposition.
Assuntos
Técnicas Bacteriológicas/métodos , Túnica Conjuntiva/microbiologia , Infecções Oculares Bacterianas/diagnóstico , Biblioteca Gênica , RNA Ribossômico 16S/genética , Análise de Sequência de DNA/métodos , Bactérias/genética , DNA Bacteriano/genética , Humanos , Filogenia , Reação em Cadeia da PolimeraseRESUMO
The bacterial community composition in the A horizon of a natural saline-alkaline soil located in Ararat Plain (Armenia) was studied using molecular and culture-based methods The sequence analysis of a 16S rRNA gene clone library and denaturing gradient gel electrophoresis (DGGE) profiles indicated dominance of Firmicutes populations. The majority of the sequences of the bacterial 16S rRNA gene library were close relatives of representatives belonging to the genera Halobacillus (41.2%), Piscibacillus (23.5%), Bacillus (23.5%) and Virgibacillus (11.8%). Eight novel moderately halophilic bacilli isolates were successfully obtained from the enriched cultures of the saline-alkaline soil samples. 16S rRNA gene sequence analyses of isolates revealed their affiliation (97.7-99.7% similarity) to representatives of the genera Bacillus, Piscibacillus and Halobacillus. All isolates were able to tolerate high concentrations of NaCl and highly alkaline conditions. This is the first study combining cultivation-independent and -dependent approaches to reveal the bacterial diversity of the saline-alkaline soils of Ararat Plain and it suggested an important role of bacilli as key microbes in biogeochemical cycles of these environments.
Assuntos
Bactérias/classificação , Consórcios Microbianos , Microbiologia do Solo , Solo/química , Álcalis/química , Armênia , Bactérias/genética , Bactérias/isolamento & purificação , Biodiversidade , DNA Bacteriano/genética , DNA Ribossômico/genética , Eletroforese em Gel de Gradiente Desnaturante , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
We enriched an anaerobic, soil-free 4-chlorophenol (4-CP)-degrading culture under iron-reducing conditions. The [ring-(14)C(U)]4-CP tracer experiment showed that 65 µM 4-CP mineralized to CO2 and CH4 through phenol, 4-hydroxybenzoate, and benzoate intermediates over 60 days. 16S rRNA gene analyses suggested the involvement of Dehalobacterium in the 4-CP dechlorination in the culture.
Assuntos
Bacillales/crescimento & desenvolvimento , Bacillales/metabolismo , Clorofenóis/metabolismo , Ferro/metabolismo , Anaerobiose , Bacillales/genética , Bacillales/isolamento & purificação , Dióxido de Carbono/metabolismo , Halogenação , Ferro/química , Metano/metabolismo , Oxirredução , Parabenos/metabolismo , Fenol/metabolismo , RNA Ribossômico 16S/genéticaRESUMO
The phylogenetic diversity of the prokaryotic community thriving in the Arzakan hot spring in Armenia was studied using molecular and culture-based methods. A sequence analysis of 16S rRNA gene clone libraries demonstrated the presence of a diversity of microorganisms belonging to the Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Epsilonproteobacteria, Firmicutes, Bacteroidetes phyla, and Cyanobacteria. Proteobacteria was the dominant group, representing 52% of the bacterial clones. Denaturing gradient gel electrophoresis profiles of the bacterial 16S rRNA gene fragments also indicated the abundance of Proteobacteria, Bacteroidetes, and Cyanobacteria populations. Most of the sequences were most closely related to uncultivated microorganisms and shared less than 96% similarity with their closest matches in GenBank, indicating that this spring harbors a unique community of novel microbial species or genera. The majority of the sequences of an archaeal 16S rRNA gene library, generated from a methanogenic enrichment, were close relatives of members of the genus Methanoculleus. Aerobic endospore-forming bacteria mainly belonging to Bacillus and Geobacillus were detected only by culture-dependent methods. Three isolates were successfully obtained having 99, 96, and 96% 16S rRNA gene sequence similarities to Arcobacter sp., Methylocaldum sp., and Methanoculleus sp., respectively.
Assuntos
Archaea/classificação , Archaea/isolamento & purificação , Bactérias/classificação , Bactérias/isolamento & purificação , Biota , Fontes Termais/microbiologia , Archaea/genética , Archaea/crescimento & desenvolvimento , Armênia , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Análise por Conglomerados , DNA Arqueal/química , DNA Arqueal/genética , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
In order to investigate the anaerobic ammonium-oxidation (Anammox) nitrogen removal pathway of the aged refuse bioreactor treating landfill leachate, a lab-scale bioreactor was established and run for 35 weeks, the performance of the bioreactor and its bacterial community structure of Planctomycetes were analyzed. The results showed that the average TN removal rate of landfill leachate could be reached to 89%. 16S rRNA gene library of Planctomycetes revealed that Anammox sequences accounted for 28.3% of the total Planctomycetes sequences in the bioreactor, and previously recognized Anammox bacterium Candidatus Kuenenia stuttgartiensis was the only detected Anammox species in the reactor. It was also found that Anammox bacteria distributed at different sites of the bioreactor while mostly concentrated in the middle and low-middle part. Results above confirmed that Anammox process could happen in aged refuse bioreactor treating landfill leachate and provided an alternative nitrogen removal pathway in practical landfills.