Search

Microbes are widespread in the sea that covers more than two-thirds of the earth's surface and most microorganisms living in the marine environment have yet to be cultured. Previous studies showed that drying treatment, a strategy of sample pre-treatment widely applied in microbial isolation and incubation, may alter the cultivable microbial diversity, such as Actinomycetota, essential for exploring novel secondary metabolites from the marine environment, isolated from drying-treated samples. However, whether drying treatments actually can change microbial community diversity and how the drying treatments of samples influence the cultivable microbial diversity of marine samples have not yet adequately been evaluated. Here, three marine sediment samples were dried and incubated at 28 ºC, 37 ºC, and 45 ºC, and the microbial diversity was assessed with high-throughput sequencing. Our results suggested that drying treatments had different effects on different genera and some potential novel species could be cultured only from drying-treated samples, including the novel members from the families Paenibacillaceae and Thermoactinomycetaceae. Non-metric multidimensional scaling analysis showed that the treated samples were clustered according to the cultivation temperatures rather than the drying conditions at high cultivation temperatures. However, at the cultivation temperatures of 28 ºC, drying treatments were the larger separation between cultivable microbial communities in the process of microbial isolation. These results showed that the drying treatments influenced the cultivated microbes in a taxon-specific pattern and extended potential novel taxa. Combining high-throughput sequencing to various drying conditions and incubation temperatures, this study provides new insight into the effects of drying treatment on the cultivable microbial diversity of marine sediments.

Biological denitrification is a significant process in nitrogen biogeochemical cycle of terrestrial geothermal environments, and Thermus species have been shown to be crucial heterotrophic denitrifier in hydrothermal system. Five Gram-stain negative, aerobic and rod-shaped thermophilic bacterial strains were isolated from hot spring sediments in Tibet, China. Phylogenetic analysis based on 16S rRNA gene and whole genome sequences indicated that these isolates should be assigned to the genus Thermus and were most closely related to Thermus caldifontis YIM 73026

Strain DRQ-2T (type strain of Nonomuraea indica) is worthy for genome sequencing, due to its ability to produce a wide variety of industrially important enzymes such as amylase, asparaginase, cellulase, gelatinase, glutaminase, and protease. Genome sequencing and comparison of strain DRQ-2T is described in the present work. The genome size was estimated to be 8,288,417 (bp) that consisted of 59 contigs. The G + C content of the genome was 72.4%. A total of 7730 genes were predicted with two rRNAs and 64 tRNAs. The genome analysis of the strain DRQ-2T showed the presence of a wide range of secondary metabolite gene clusters. Pan-Genomes Analysis Pipeline (PGAP) indicated that strain DRQ-2T had large numbers of unique genes. The majority of N. indica DRQ-2T genes encode for hypothetical proteins, indicating the functions of these ortholog clusters were still remain to be determined.

Two closely related, thermophilic bacteria, designated strains YIM 76954T and YIM 76947, were isolated from the Rehai Geothermal Field, Tengchong, Yunnan province, south-west China. Polyphasic approach and whole genome sequencing were used to determine the taxonomy status and genomic profiles of the novel strains. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the two isolates were closely related to Thermus scotoductus SE-1T (97.1% sequence similarity), and T. amyloliquefaciens YIM 77409T (96.6%). The strains could be differentiated from most recognized Thermus species by their whitish to slight reddish colony color, distinct DNA fingerprinting profiles and low ANI values. Cells stained Gram-negative, rod-shaped of diameter 0.2-0.5μm and length 1.5-5.0μm. Growth occurred at 50-75°C, pH 6.0-9.0 and in the presence of up to 1.0% (w/v) NaCl concentration. Thiosulfate was found to enhance cell growth, besides improving the intensity of its colony color. Oxygen, nitrate, sulfur, and Fe(III) could be used as terminal electron acceptors for growth. MK-8 was the major respiratory menaquinone. Major fatty acids were iso-C17:0, iso-C15:0, anteiso-C17:0, and anteiso-C15:0. The genome size was 2.26Mbp with 65.5% average GC content. A total of 2374 genes was predicted, comprising 2322 protein-coding and 52 RNA genes. On the basis of the polyphasic evidence presented, it is proposed that strain YIM 76954T represents a novel species of the genus Thermus, for which the name Thermus tenuipuniceus sp. nov. is proposed. The type strain is YIM 76954T (=JCM 30350T=KCTC 4677T).

Lignocellulose is considered a major source of renewable energy that serve as an alternative to the fossil fuels. Members of the genus Clostridium are some of the many microorganisms that have the ability to degrade lignocellulose efficiently to sugar, which can be further converted to biofuel. In this study, we isolated twelve Clostridium strains from hot spring samples of Yunnan and Tibet, of which isolates SYSU GA15002T and SYSU GA17076 showed low 16S rRNA gene sequence identity profiles to any of the validly named Clostridium strains (