Sesquiterpenes and α-pyrones from an endophytic fungus Xylaria curta YSJ-5.

Chemical investigation of the culture extract of an endophyte Xylaria curta YSJ-5 from Alpinia zerumbet (Pers.) Burtt. et Smith resulted in the isolation of eight previously undescribed compounds including five eremophilane sesquiterpenes xylarcurenes A-E, one norsesquiterpene xylarcurene F, and two α-pyrone derivatives xylarpyrones A-B together with eight known related derivatives. Their chemical structures were extensively established based on the 1D- and 2D-NMR spectroscopic analysis, modified Mosher's method, electronic circular dichroism calculations, single-crystal X-ray diffraction experiments, and the comparison with previous literature data. All these compounds were tested for in vitro cytotoxic, anti-inflammatory, α-glucosidase inhibitory, and antibacterial activities. As a result, 6-pentyl-4-methoxy-pyran-2-one was disclosed to display significant antibacterial activity against Staphylococcus aureus and methicillin-resistant S. aureus with minimal inhibitory concentration value of 6.3 µg/mL.

[Spatial Patterns of Nitrogen and Phosphorus in Soil and Their Influencing Factors in a Typical Agro-pastoral Ecotone].

Soil nitrogen and phosphorus influence physical, chemical, and biological processes in soil, therefore, clarifying their contents and spatial patterns is of great significance for soil resource management and utilization. The spatial patterns of soil total nitrogen (TN) and phosphorus (TP) and the influencing factors in Jungar Banner were studied using classical statistical and geostatistical methods. The results showed that soil TN and TP contents decreased with soil depth, and the weighted mean values of TN and TP were 0.29 g·kg-1 and 0.26 g·kg-1, respectively. The nugget effect values of soil TN and TP were concentrated in the ranges 0.15-0.43 and 0.34-0.53, respectively, indicating that soil TN (except in the 0-10 cm and 80-100 cm zones) and TP were moderately spatially dependent, dominated by structural and random factors. The spatial distributions of soil nutrients were related to soil layers and elements, even in same layer, while the distributions of TN and TP were not consistent. Soil total nitrogen was mainly affected by soil organic carbon, while TP was mainly affected by latitude, altitude, vegetation, and soil texture.

[Filamentous Sludge Microbial Community of a SBR Reactor Based on High-throughput Sequencing].

Samples were collected from a sequencing batch reactor (SBR) to characterize the similarities and differences in microbial community composition in samples using Illumina high-throughput sequencing. The main objective of this study was to characterize changes in microbial community composition during filamentous sludge bulking and control processes. The SBR working volume was 11 L, and the reactors were operated for 399 days in total. High-throughput sequencing results indicated that rich diversity existed in the microbial communities of the seeding sludge. Generally, during sludge bulking, microbial composition decreased, and after the sludge was remediated, the diversity gradually increased. The dominant bacteria in the seeding sludge were Saprospiraceae_norank, Comamonadaceae_unclassified, and Tetrasphaera, comprising 13.37%, 10.54%, and 8.59% of the community, respectively. After culturing using sodium acetate as the sole carbon source, Thiothrix and Trichosporon increased significantly from the seeding to the bulking sludge, with ranges from 0.1% to 60.14% and from 19.60% to 94.82%, respectively. After the sludge bulking was controlled, the relative abundances of Thiothrix and Trichosporon were 0.1% and 2.32%, respectively. Therefore, we postulate that increases in filamentous Thiothrix and Trichosporon were the main cause for the sludge bulking.