A novel member of extremely halophilic archaea, strain AJ2, was isolated from Ayakekum Lake located in Altun Mountain National Nature Reserve of Xinjiang Uygur Autonomous Region in China. The strain AJ2 requires at least 10% (w/v) NaCl and grows 10% to 30% (optimum at 20%). Phylogenetic analysis based on 16S rDNA sequence comparison revealed that strain AJ2 clustered to three Natrinema species with less than 97.7% sequence similarities, suggesting AJ2 is a novel member of Natrinema. A bacteriorhodopsin-encoding (bop) gene was subsequently detected in the AJ2 genome using the polymerase chain reaction technique. The cloning and sequencing of a 401 base pairs fragment indicated the deduced amino acid sequence of bop from AJ2 is different from that reported for bacteriorhodopsins. This is the first reported detection of a bop gene in Natrinema.
Bacteriorhodopsins ; genetics ; metabolism ; Cell Proliferation ; Gene Expression Profiling ; Genome, Archaeal ; Halobacteriaceae ; classification ; isolation & purification ; physiology ; Phylogeny ; Sequence Analysis, DNA ; Species Specificity

Soil archaea and fungi play important roles in the greenhouse soil ecosystem. To develop and apply rich microbial resources in greenhouse ecological environment, and to understand the interaction between microbes and plants, we constructed archaeal 16S rRNA and fungal 18S rRNA gene libraries to analyze the compositions of archaeal and fungal communities. Total greenhouse soil DNA was directly extracted and purified by skiving-thawing-lysozyme-proteinase K-SDS hot treatment and treatment of cetyltriethylammnonium bromide (CTAB). After PCR amplification, retrieving, ligating, transforming, screening of white clones, archaeal 16S rRNA and fungal 18S rRNA gene libraries were constructed. The sequences of archaea and fungi were defined into operational taxonomic units (OTUs) when 97% similarity threshold for OTU assignment was performed by using the software DOTUR. Phylogenetic analysis showed that crenarchaeota and unidentified-archaea were the two major sub-groups and only a few of euryarchaeota existed in the archaeal clone library, total 45 OTUs. All the crenarchaeota belonged to thermoprotei; except for Basidiomycotina, the other four sub-group fungi were discovered in the fungal library, total 24 OTUs. The diversities of archaea were very abundant and a few euryarchaeota (methanebacteria) existed in the archaeal clone library, it might be directly related to the long-term high temperature, high humidity, and high content of organic matter. The limitation of oxygen was the other reason for causing this phenomenon; Ascomycotina (over 80%) was the dominant sub-groups in fungal library. It was because most of the plant fungal diseases belonged to soil-borne diseases which gone through the winter by the ways of scierotium or perithecium and became the sources of primary infection.
Archaea ; genetics ; growth & development ; Biodiversity ; Cloning, Molecular ; Cucumis sativus ; growth & development ; Fungi ; genetics ; growth & development ; Gene Library ; Genes, rRNA ; Microclimate ; Phylogeny ; Plant Roots ; microbiology ; RNA, Archaeal ; genetics ; RNA, Fungal ; genetics ; RNA, Ribosomal, 16S ; genetics ; RNA, Ribosomal, 18S ; genetics ; Soil Microbiology