A pilot survey on antimicrobial activity and diversity of soil-derived actinobacteria from different depths in Gudzhirganskoe saline lake in Eastern Siberia

To explore pharmaceutical actinobacteria from salty environments in Siberia,8 soil samples were collected from different depths of Gudzhirganskoe saline lake,the Republic of Buryatia,Russia.Totally,635 actinobacterial strains affiliated with 21 genera in 12 families of 7 orders were obtained by culture-dependent approaches.The predominant genus was Streptomyces(74.5%),followed by Microbacterium(4.9%),Agromyces(3.5%),Nocardiopsis(3.0%),and Kitasatospora(2.5%).Seven strains showed relatively low 16 S rRNA similarities(<98.65%)with validly described species.Seventy-seven strains were selected as representatives to evaluate their antimicrobial activities and underlying mechanisms by paper-disk diffusion method and a double fluorescent protein reporter system(pDualrep 2),respectively.Streptomyces sp.S 6 b 3-1 was highlighted due to its strong inhibitory activities against Gram-positive bacteria and underlying antibacterial mechanism by inducing the SOS response in the reporter system.LG-1,(R)-6-[1-(benzoyloxy)ethyl]-phenazine-1-carboxylic acid,an analogue of saphenamycin was finally isolated from the culture broth of Streptomyces strain.This study preliminarily explored the actinobacterial diversity of soil samples collected in the highly alkaline and saline lake Gudzhirganskoe by culture-dependent approach and their capacity to produce antibiotics for the first time,which revealed that it deserves to make more efforts to discover new actinobacterial species and potential new antibiotics from the saline lake in Eastern Siberia.

Numerical simulation and analysis of drill rods vibration during roof bolt hole drilling in underground mines

Structural deterioration in the roof in an underground mine can easily cause roof fall, and deterioration is difficult to detect. When drilling holes for roof bolts, there is a relationship between the vibration of the drill rod and the properties of the rock being drilled. This paper analyzes transverse, longitudinal, and torsional vibrations in the drill rod by using vibration theory. Characteristic indexes for three kinds of vibration are determined. Using the finite element analysis software ABAQUS, a model for drill rod vibration during the drilling of roof bolt holes was established based on the geological and mining conditions in the Guyuan Coal Mine, northern China. Results from the model determined that the transverse and the longitudinal vibration decrease as the rock hardness decreases. In descending order, sandstone,sandy mudstone, mudstone, and weak interbeds cause progressively less vibration when being drilled.The ranking for strata that cause decreasing torsional vibration is slightly different, being, in descending order, mudstone, sandstone, sandy mudstone, and weak interbeds. These results provide a theoretical basis for predicting dangerous roof conditions and the presence of weak interbeds to allow for adjusting bolt support schemes.

Diversity, novelty, antimicrobial activity, and new antibiotics of cultivable endophytic actinobacteria isolated from psammophytes collected from Taklamakan Desert

Three hundred and twenty endophytic actinobacterial strains were isolated from psammophytes collected from Taklamakan Desert and identified. Among them, three strains already had been identified as new species of two genera and sixteen isolates showed relatively low 16 S rRNA similarities < 98.6% to validly described species. Seventy-five of the isolates were selected as representative strains to screen antibacterial activity and mechanism. Forty-seven strains showed antagonistic activity against at least one of the indicator bacteria. Two Streptomyces strains produced bioactive compounds inducing DNA damage, and two Streptomyces strains produced bioactive compounds with inhibitory activity on protein biosynthesis. Notably, the strain Streptomyces sp. 8P21H-1 that demonstrated both strong antibacterial activity and inhibitory activity on protein biosynthesis was prioritized for exploring new antibiotics.Under the strategy of integrating genetics-based discovery program and MS/MS-based molecular networking, two new streptogramin-type antibiotics, i.e., acetyl-griseoviridin and desulphurizing griseoviridin, along with known griseoviridin, were isolated from the culture broth of strain 8P21H-1. Their chemical structures were determined by HR-MS, and 1D and 2D NMR. Desulphurizing griseoviridin and griseoviridin exhibited antibacterial activities by inhibiting translation.

Anchoring eccentricity features and rectifying devices for resin grouted bolt/cable bolt

The anchoring eccentricity of the bolt and cable bolt is a common problem in geotechnical support engineering and affects the ability of the bolt and cable bolt to control the rock mass to a certain extent.This paper reports on numerical simulation and laboratory experiments conducted to clarify the effect of eccentricity on the anchoring quality of the bolt and cable bolt,and to establish an effective solution strategy.The results reveal that the anchoring eccentricity causes unbalanced stress distribution and the uncoordinated deformation of the resin layer,which results in higher stress and greater deformation of the resin layer at the near side of the rod body.Additionally,as the degree of anchoring eccentricity increases,the effect becomes more significant,and the resin layer of the anchoring system becomes more likely to undergo preferential failure locally,which weakens the load-bearing performance of the anchoring system.This paper develops an innovative bolt anchoring rectifying device(B-ARD)and cable bolt anchoring rectifying device(C-ARD)on the basis of the structural characteristics of the bolt and cable bolt to better ensure the anchoring effect of them.The working effects of these two devices were verified in detailed experiments and analysis.The experimental results show that the anchoring rectifying devices(ARD)improve and ensure the anchoring concentricity of the bolt and cable bolt,which will help improve the supporting performance of them.The paper provides a convenient and effective method for improving the anchoring concentricity of the bolt and cable bolt,and provides a concept and reference for technical research on improving the effect of roof bolting.

Macro and micro grouting process and the influence mechanism of cracks in soft coal seam

Grouting is an important method to reinforce soft coal roadway,and the presence of primary cracks in the coal body has an important influence on the grouting effect.With the discrete element simulation method,the grouting process of the soft coal seam was simulated.The mechanism of primary cracks on grouting was revealed,while the influence of fracture characteristics and grouting pressure on the grouting effect was analyzed.The results demonstrated that grouting in the soft coal seam involves the stages of seepage,rapid splitting,slow splitting,and stability.Due to the presence of primary cracks,the grouting diffusion radius increased significantly.Under the slurry pressure,the tensile stress concentration was formed at the crack tip,and the slurry split the coal once the splitting pressure was reached.In addition,the distribution characteristics of fractures are found to have a great influence on the grouting effect.It is observed that smaller fracture spacing is associated with a larger slurry diffusion radius and thus easier penetration of the primary crack tips.The fracture angle affects the direction of fracture propagation.The secondary fracture formed by splitting is a tensile fracture,which is more likely to extend along the direction parallel to the maximum principal stress.Overall,these simulation results have guiding significance for the setting of reasonable spacing of grouting holes in the practice of grouting engineering.

国资委聚焦管理会计发展,推动中央企业加快世界一流财务体系建设

近年来,在财政部领导和会计司的直接领导下,在中总协大力推动下,在各方面的积极支持下,管理会计广泛应用于企业财务管理转型升级和创新变革中,加上高校财务会计领域专家教授们的深度参与和深入研究,目前已经基本形成与我国社会主义市场经济体制相适应的、具有中国特色的管理会计理论体系、工具方法和创新实践,实现了管理会计在企业财务管理实务中新的跨越和新的飞跃。

推进央企司库建设 构建一流财务管理体系

一、中央企业司库管理体系建设意义重大党中央、国务院高度重视数字经济,党的十八大以来已将发展数字经济上升为国家战略。发展数字经济意义重大,是把握新一轮科技革命和产业变革新机遇的战略选择。在这种时代背景下,推动我国企业特别是中央企业加快司库管理体系建设具有非常重要的现实意义。