Lianbing Lin

Background: Drug-resistant Mycobacterium tuberculosis (MTB) is a major threat to tuberculosis (TB) control programs and public health. Most conventional methods of drug susceptibility testing (DST) are precise but time-consuming. Molecular analysis of the rpsL gene has been used widely in diagnosing streptomycin-resistant MTB since it is rapid and specific. The aim of the present study was to perform a meta-analysis to assess the accuracy of molecular assay of the rpsL gene for the rapid detection of streptomycin-resistant MTB. Methods: We searched PubMed, Web of Science, and EBSCO databases for studies that applied a molecular assay of the rpsL gene to detect streptomycin-resistant MTB with a conventional method as the reference. The sensitivity and specificity were pooled by a random effect model using Meta-DiSc software. A summary receiver operating characteristic curve (SROC) was applied to summarize the diagnostic accuracy. Results: A total of 22 studies involving 2618 specimens with 1372 streptomycin-resistant and 1246 streptomycin-susceptible specimens met our inclusion criteria. The overall sensitivity and specificity estimates were 0.64 (95% confidence interval (CI) 0.61-0.66) and 1.00 (95% CI 0.99-1.00), respectively. The area under the SROC curve was 0.9069 and the Cochrane (Q*) index was 0.8387. Conclusions: This meta-analysis reveals that molecular assay of the rpsL gene is a reliable and useful method for the detection of streptomycin-resistant MTB.

A newly isolated single-tailed fusiform virus, Sulfolobus tengchongensis spindle-shaped virus STSV2, from Hamazui, China, is characterised. It contains a double-stranded modified DNA genome of 76,107 bp and is enveloped by a lipid membrane structure. Virions exhibit a single coat protein that forms oligomers when isolated. STSV2 is related to the single-tailed fusiform virus STSV1 and, more distantly, to the two-tailed bicaudavirus ATV. The virus can be stably cultured over long periods in laboratory strains of Sulfolobus and no evidence was found for cell lysis under different stress conditions. Therefore, it constitutes an excellent model virus for archaeal virus–host studies.

A thermophilic bacterium, designated strain RHA1^T, was isolated from a sediment sample collected from a hot spring in Tengchong county, Yunnan province, south-west China, and was characterized by using a polyphasic approach. Based on its phenotypic and phylogenetic characteristics, strain RHA1^T was affiliated to the genus Laceyella. The strain formed white aerial and yellow–white substrate mycelia, bearing single endospores on short sporophores. The cell-wall peptidoglycan contained meso-diaminopimelic acid. Whole-cell hydrolysates contained ribose and glucose. The major fatty acids were iso-C_15 : 0 (62.39 %) and anteiso-C_15 : 0 (17.55 %)_. The predominant menaquinone was MK-9. The G+C content of the genomic DNA of strain RHA1^T was 47.9 mol%. Based on DNA–DNA hybridization data, chemotaxonomic characteristics and differential physiological properties, strain RHA1^T is considered to represent a novel species of the genus Laceyella, for which the name Laceyella sediminis sp. nov. is proposed; the type strain is RHA1^T ( = DSM 45263^T = CCTCC AA 208058^T).

Thermophiles and their viruses are extraordinarily important because of their roles in processes of evolution, biogeochemistry and ecology. Species of the genus Meiothermus share close relationship with genus Thermus, but no Meiothermus bacteriophage has been reported yet. In this work, a new thermophilic bacteriophage named MMP17 (Meiothermus Myoviridae phage 17) was isolated from a Meiothermus strain and was further characterized. MMP17 was a typical myovirus with an icosahedral head (42 nm in diameter) and a tail (120 nm in length and 17 nm in width). Its DNA was about 33.5–39.5 kb in size. MMP17 was very stable at 55–60°C and pH 6–7. According to the one-step growth curve, the latent period and the burst period were 60 and 30 min, respectively. An average of 15 phage particles was released from each infected cell. Four major bands were detected in purified virion preparation by SDS-PAGE. As MMP17 was a thermophilic bacteriophage with lower production temperature, its characterization and the relationship between MMP17 and Thermus bacteriophages deserved for further study.

硫化叶菌（Sulfolobus）是极端嗜热古菌遗传机制研究的重要模式菌株，广泛分布于酸性热泉中. 对分离自云南腾冲酸性热泉的11株极端嗜酸热菌株进行16S rRNA基因序列测定，并通过菌体形态观察、16S rRNA基因可变区序列比较、菌株16S rRNA基因相似性比较及系统发育分析，研究腾冲热泉硫化叶菌的多样性. 结果表明，分离自腾冲热泉的11株硫化叶菌的16S rRNA基因序列与分离自世界上其它地区的 8个硫化叶菌的标准菌株的相似性为85.8%~94.9%，与同样分离自腾冲热泉的S. tengchongensis 标准菌株的相似性为96.6%~97.5%，在分类学上具有形成新种的可能. 在16S rRNA基因高可变区序列上，与分离自世界上其它地区的8个硫化叶菌的标准菌株存在明显的差异. 系统发育分析表明，分离自腾冲热泉的硫化叶菌在系统发育树上形成两个亲缘关系较为紧密的簇群，可见腾冲热泉硫化叶菌不仅具有一定的多样性，同时具有较明显的地域性特征. 图2 表3 参16

Thermus strains are regarded as models to investigate the mechanism of thermostability of thermophiles, and phages from Thermus are particularly interesting because of their way to regulate gene expression. In this research, a Thermus bacteriophage named TSP4 (Thermus Siphoviridae phage) was isolated from Tengchong hot springs in China, and characteristics of morphology, temperature for phage production, pH and organic solvent sensitivity, DNA restriction endonuclease digestion and protein composition of TSP4 were further studied. TSP4 belonged to the Siphoviridae family and had a hexagonal head of 73 nm in diameter, an extremely long and flexible tail of 785 nm in length and 10 nm in width. TSP4 was very stable at 65 °C and pH 7.6. The capsid was apparently devoid of lipid. By SDS‐PAGE, six protein bands were found in purified virions. Despite their exceptional habitats separated by thousands of kilometers, the characteristics of this thermophilic phage showed high similarity to Thermus siphoviruses P23‐45 and P74‐26 isolated from Kamchatka peninsula hot springs in the Far East, Russia.