[Evaluation of eutrophication level changes in Baiyangdian Lake based on multiple biological groups]. / 应用多种生物类群评价白洋淀水环境质量变化.

Baiyangdian Lake is the largest shallow lake in the North China Plain. Due to the increases in upstream water consumption in recent decades, the amount of natural water entering the lake has decreased, resulting in a significant drop in the water level of Baiyangdian Lake. Severe eutrophication has occurred in Baiyangdian Lake owing to the discharge of domestic sewage around the sub-lakes. With the establishment of the Xiong'an New Area in 2017, the importance of environmental governance and protection of Baiyangdian Lake has been unprecedentedly increased. The implementation of ecological water supplement from upstream reservoirs and other basins has significantly increased water level of Baiyangdian Lake. Moreover, domestic sewage from surrounding rural areas was collected. In order to understand the current state of water quality in Baiyangdian Lake, and to evaluate the effects of the previous water replenishment and pollution control projects, we investigated water physicochemical variables and aquatic organisms of Baiyangdian Lake in August 2019. We evaluated water quality status of Baiyangdian Lake based on water quality, phytoplankton, zooplankton and macrozoobenthos, by comparing with the evaluation based on the survey data in 2010. In addition, submerged macrophytes were used to evaluate the water ecological status. The results showed that the water quality state of Baiyangdian Lake in 2019 was greatly improved compared with 2010. Among them, total phosphorus concentration decreased by 88.6%, total nitrogen concentration decreased by 83.9%, chlorophyll a concentration decreased by 47.8%, and the Seechi depth increased by 43.4%. The diversity of zooplankton and macrozoobenthos were significantly increased, the density of phytoplankton was significantly reduced, the dominant species of phytoplankton changed from a general highly eutrophic type to a eutrophic type, and the distribution of the clean-type submerged macrophytes was narrowed. The evaluation methods based on submerged macrophytes species and based on zooplankton diversity were not suitable for water quality evaluation in Baiyangdian Lake. In the early stage, the pollution source of Baiyangdian Lake was concentrated in the west, which led to lower water quality. Nowadays, due to the water replenishment from the west, north and south, the hydrodynamic conditions changed significantly. In the west, pollution control projects were carried out, and the spatial distribution of water quality in Baiyangdian Lake are showing a characteristics of homogenization.

Effects of enhanced UV-B radiation on the nutritional and active ingredient contents during the floral development of medicinal chrysanthemum.

The paper mainly studied the effects of enhanced UV-B radiation on the nutritional and active ingredient contents during the floral development of medicinal chrysanthemum. The experiment included two levels of UV-B radiation (0 and 400µWcm(-2)). The contents of hydrogen peroxide (H2O2), anthocyanin, UV-B absorbing compounds, total chlorophyll and carotenoids, and the activities of phenylalanine ammonia lyase enzyme (PAL) and cinnamic acid-4-hydroxylase enzyme (C4H) in flowers significantly decreased with the floral development. However, the contents of soluble sugar, amino acid and total vitamin C in flowers significantly increased with the floral development. The contents of flavonoid and chlorogenic acid were significantly different in the four stages of floral development, and their highest contents were found in the bud stage (stage 2). In the four stages of floral development, enhanced UV-B radiation significantly increased the contents of H2O2, UV-B absorbing compounds, chlorophyll, carotenoids, soluble sugar, amino acid, vitamin C, flavonoid and chlorogenic acid, and the activities of PLA and C4H in flowers. The results indicated that the highest contents of active and nutrient ingredients in flowers were found not to be in the same developmental stages of flowers. Comprehensive analysis revealed that the best harvest stage of chrysanthemum flowers was between the bud stage and the young flower stage (stage 2 and stage 3), which could simultaneously gain the higher contents of active and nutritional ingredients in flowers.

[A redox process of ethanethiol group increases formation of beta-sheet structure and amyloid fibrils of wild type human prion protein].

In order to explore the potential influences of the disulfide bridge on the physical and chemical properties of PrP protein, the expressed recombinant human wild-type PrP protein was purified for using in an established redox process for the reduction and oxidation of the ethanethiol group within PrP. Sedimentation tests illustrated that redox process remarkably promoted the aggregation of recombinant PrP. Thioflavin T binding assay revealed an enhanced fibrillization of the recombinant human PrP after redox process. Far-UV circular dichroism demonstrated that the PrP treated with redox process showed a significant p-sheet rich structure. Furthermore, PrP-specific Western blot identified that the recombinant PrP after redox possessed stronger proteinase K-resistance. Those data indicates that the formation of the disulfide bridge induces the alteration of the secondary structure and enhances the progresses of aggregation and fibrillization of PrP protein.

[Effects of salinity and Na+/K+ in percolating water from saline-alkali soil on the growth of Litopenaeus vannamei].

In order to develop shrimp farming with the percolating water from coastal saline-alkali soil, the effects of the salinity and Na+/K+ in this percolating water on the survival, growth, metabolism, and glutamic oxaloacetic transaminase (GOT), glutamicpyruvic transaminase (GPT) and Na+-K+-ATPase activities of Litopenaeus vannamei were investigated. The shrimps were cultured at the salinity 5, 10 and 15 and at the Na+/K+ ratios of 20, 40, 50, 60, 70 and 90 for 20 days. The results showed that the survival rate, growth rate, and enzyme activities of the shrimps were the highest at salinity 15, and the shrimps had higher survival rate, growth rate, and enzyme activities at the Na+/K+ ratios of 40 and 50, suggesting that after an appropriate preparation, the percolating water from coastal saline-alkali soil was available to culture the shrimps.