Search

Abstract: In this study, chitooligosaccharides were prepared from cicada slough of Cryptotympana atrata Fabricius by hydrolysis using hydrogen peroxide (H2O2). Factors affecting the hydrolysis of chitosan were investigated and the optimum hydrolysis conditions were as follows: time, 4h; temperature, 65°C; amount of H2O2, 2% (v/v); and pH, 5. Under these conditions, the average degree of polymerisation decreased to ∼4.5. The Fourier transform infrared spectra and product sugar composition indicate that there were no significant chemical changes in the backbones of the chitosan treated with H2O2.The chitooligosaccharides had high antibacterial activity against Bacillus subtilis, Staphylococcus aureus, and Escherichia coli at the concentration of 100mg/mL. [Copyright &y& Elsevier]

Small reservoirs in the Yangtze River are large in quantity and widely distributed, which have important ecological and economic benefits. It is of great significance to explore the response law of small reservoir water quality to environmental variables for improving reservoir water quality. Based on the measured water quality data of 36 small reservoirs in the upper reaches of the Yangtze River, combined with the measured water quality data, using correlation analysis, redundancy analysis, and other research methods, we divided the environmental variables into three categories:landscape configuration index, landscape composition index, and reservoir characteristic index, and explored their impact on the change in water quality index. The research results showed that:① farms were the main source of NO 3 - -N, TN, and TP, and residential land was the main source of TP. Paddy, forest land, and wasteland had positive effects on the retention and purification of N and P in reservoirs. ② The LPI of farms was significantly positively correlated with the concentrations of TN and NO 3 - -N in the reservoir, and the paddy and forest were significantly negatively correlated with the concentrations of NO 3 - -N and TN in the reservoir. The PD of farms was positively correlated with TP. The LPI was negatively correlated with TP content. ③ The correlation between average reservoir depth and reservoir water quality was the strongest. Reservoir capacity, reservoir average depth, and reservoir LSI had significant positive effects on water quality improvement. ④ Among the environmental variables of the reservoir, landscape configuration index had the highest explanatory rate (24%), followed by that of the reservoir characteristics index (11%) and landscape composition index (9%). Watershed factors were the key factors (55%), and internal factors (19%) also had a significant influence on reservoir water quality. The research results can provide a theoretical basis for controlling water quality degradation of small reservoirs by managing and optimizing the landscape characteristics of reservoirs.

Invasive process of alien species is affected by not only the invaded habitats, but also the surrounding landscape matrix. Understanding the effects of landscape matrix on alien species is of great significance for controlling invasive alien species. We surveyed plant communities along the water-level fluctuating zone (WLFZ) of the Three Gorges Reservoir. Invasive status of alien plant species was evaluated. Totally 10 spatial scales of the surrounding landscape matrix in the scope of 2000 m (including WLFZ) were classified, and 14 landscape indices were applied to analyze the landscape matrix composition and configuration. Using the principal component analysis and correlation analysis, the effects of landscape matrix on the alien invasive plant species and associated scale effect were tested. Results showed that a total of 42 alien invasive plant species were found in the WLFZ, belonging to 17 families and 36 genera. Fuling was a dividing place to differentiate invasive species distribution. The number of the alien invasive species between Fuling and the Three Gorges Dam was found more than that between Fuling and Jiangjin. For the all scales (within 2000 m). The higher the landscape matrix fragmentation was, the more difficult the alien species invading. The higher landscape connectivity was, the easier the alien species invading. The effects of landscape matrix composition and configuration on the invasive plant diversity at large scales (1200-2000 m) was more significant than those at small scales (200-1000 m), in which landscape matrix composition and configuration at 1200-1400 m showed the strongest effect, demonstrating a significant spatial scale effect. Different invasive plant species showed the scale effects of landscape matrix composition and configuration. At all scales, Xanthium strumarium and Bidens frondosa showed weak correlations with landscape indices, but Bidens tripartita and Erigeron canadensis showed strong correlations. Landscape matrix was closely related to invasive plant species, and demonstrated a significant scale effect. The alien invasive plant species could be traced to the landscape matrix at large scales. Grassland and forest patches at the small scales could be used as the 'stepping stone' for the alien species transiting before they arrived at the WLFZ. In order to control alien plants in the WLFZ, land-use management and optimization should be strengthened at different scales of landscape matrix on the basis of enhancement of habitat management. A diversified comprehensive control for alien species should thus be taken into account.

Aim: To investigate the anti-proliferation and apoptosis-inducing effects of sodium aescinate (SA) on retinoblastoma Y79 cells and its mechanism., Methods: Y79 cells were cultured at different drug concentrations for different periods of time (24, 48, and 72h). The inhibitory effect of SA on proliferation of Y79 cells was detected by the cell counting kit-8 (CCK-8) assay, and the morphology of Y79 cells in each group was observed under an inverted microscope. An IC50 of 48h was selected for subsequent experiments. After pretreatment with SA for 24 and 48h, cellular DNA distribution and apoptosis were detected by flow cytometry. Real-time qunatitative polymerase chain reaction (RT-qPCR) and Western blot were used to assess changes in related genes (CDK1, CyclinB1, Bax, Bcl-2, caspase-9, caspase-8, and caspase-3)., Results: SA inhibited proliferation and induced apoptosis of Y79 cells in a time-dependent and concentration-dependent manner. Following its intervention in the cell cycle pathway, SA can inhibit the expression of CDK1 and CyclinB1 at the mRNA and protein levels, and block cells in the G2/M phase. In caspase-related apoptotic pathways, up-regulation of Bax and down-regulation of Bcl-2 caused caspase-9 to self-cleave and further activate caspase-3. What's more, the caspase-8-mediated extrinsic apoptosis pathway was activated, and the activated caspase-8 was released into the cytoplasm to activate caspase-3, which as a member of the downstream apoptotic effect group, initiates a caspase-cascade reaction that induces cell apoptosis., Conclusion: SA inhibits the proliferation of Y79 cells by arresting the cell cycle at the G2/M phase, and induces apoptosis via the caspase-related apoptosis pathway, indicating that SA may have promising potential as a chemotherapeutic drug., (International Journal of Ophthalmology Press.)