Succession characteristics of phytoplankton functional groups and ecological assessment in a cold spring-type urban lake, China.

Phytoplankton functional groups have been increasingly utilized in elucidating and predicting the response of phytoplankton species to environmental conditions and seasonal succession in various aquatic systems including lakes, rivers and reservoirs. However, it is still unclear whether the trait-based functional classification can be applied to spring-type lakes. To understand the temporal and spatial characteristics of phytoplankton functional groups and their responses to environmental factors in spring-type urban lake in northern China, an investigation was conducted in Daming Lake from May 2020 to September 2021. The findings revealed the identification of 98 phytoplankton taxa belonging to 6 phyla, predominantly being Chlorophyta (39.8%), Bacillariophyta (35.7%) and Cyanophyta (15.3%). The dominant species were Microcystis sp., Merismopedia minima, Synedra acus and Scenedesmus quadricauda. These phytoplankton taxa were categorized into 21 functional groups, with 6 dominant functional groups (abbreviated as D, MP, P, J, Lo, and W1). Among them, the functional group D, primarily constituted by S. acus, exhibited absolute predominance. The seasonal succession sequence of the dominant functional groups was as follows: D/P/J/MP/ Lo →→ D/P/W1/MP/Lo/J → D/P/J → D/MP → D/P/MP. Throughout the investigation period, the trophic level index (TLI) ranged from 39.10 to 71.13, and the Q index was from 1.91 to 2.91, both indicating a medium health state for Daming Lake, which was consistent with the evaluation results of the diversity index. The results of redundancy analysis revealed that the main driving factors of phytoplankton FG biomass and composition were water temperature (WT), total nitrogen (TN), transparency (SD), TN:TP (N:P), redox potential (ORP), chemical oxygen demand (CODMn) and pH. The dominance of the functional group D positively correlated with water temperature, TN, CODMn, pH and N:P but negatively correlated with SD. It was observed that functional groups and the Q index can objectively indicate the seasonal succession of phytoplankton and the water quality status of Daming Lake. Our discoveries have significant implications for the comprehension of the effects of urbanization on phytoplankton dynamics and for enhancing lake management practices to foster sustainable urban development.

Characteristics of plant trait network and its influencing factors in impounded lakes and channel rivers of South-to-North Water Transfer Project, China.

Trait-based approaches have been widely used to evaluate the effects of variable environments on submerged macrophytes communities. However, little research focused on the response of submerged macrophytes to variable environmental factors in impounded lakes and channel rivers of water transfer project, especially from a whole plant trait network (PTN) perspective. Here, we conducted a field survey designed to clarify the characteristic of PTN topology among impounded lakes and channel rivers of the East Route of South-to-North Water Transfer Project (ERSNWTP) and to unravel the effects of determining factors on the PTN topology structure. Overall, our results showed that leaf-related traits and organ mass allocation traits were the hub traits of PTNs in impounded lakes and channel rivers of the ERSNWTP, which traits with high variability were more likely to be the hub traits. Moreover, PTNs showed different structures among impounded lakes and channel rivers, and PTNs topologies were related to the mean functional variation coefficients of lakes and channel rivers. Specially, higher mean functional variation coefficients represented tight PTN, and lower mean functional variation coefficients indicated loose PTN. The PTN structure was significantly affected by water total phosphorus and dissolved oxygen. Edge density increased, while average path length decreased with increasing total phosphorus. Edge density and average clustering coefficient showed significant decreases with increasing dissolved oxygen, while average path length and modularity exhibited significant increases with increasing dissolved oxygen. This study explores the changing patterns and determinants of trait networks along environmental gradients to improve our understanding of ecological rules regulating trait correlations.

Characterization of the complete mitochondrial genome of Garra motuoensis (Cypriniformes: Cyprinidae) and its phylogenetic position within genus Garra.

Garra motuoensis, an endemic labeonine fish, was reported distributed in the lower Yarlung Tsangpo River drainage with little published biological information. Herein, we sequenced and characterized the complete mitochondrial genome of G. motuoensis, which was 16,806 bp in length, containing 13 PCGs, 22 tRNA genes, two rRNA genes, one light strand replication origin (OL ), one control region (D-loop), and one replication region. Phylogenetic analysis based on 13 PCGs sequences revealed that G. motuoensis had a closest relationship with G. qiaojiensis. Then, both species clustered with other species of Garra, and next grouped with other genera of subfamily Labeoninae.

Protective effect of hawthorn vitexin on the ethanol-injured DNA of BRL-3A hepatocytes.

ABSTRACT: Vitexin is a natural active ingredient in hawthorn leaves, which has a wide range of anti-tumor effects. This study was conducted to assess the protective effect of hawthorn vitexin on the ethanol-injured DNA of hepatocytes in vitro and to explore its mechanism. The effect of different concentrations of hawthorn vitexin on ethanol-injured hepatocytes was detected via the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method to study the protective effect of hawthorn vitexin on ethanol-injured DNA damage in hepatocytes. Single-cell gel electrophoresis was used to observe the effect of hawthorn vitexin on ethanol-induced DNA damage in hepatocytes, and the Olive tail moment was measured. Cell physiological and biochemical indexes, such as superoxide dismutase activity, malonaldehyde content, and glutathione peroxidase activity, were detected with kits. The mRNA expression of the superoxide dismutase gene was measured via real-time quantitative polymerase chain reaction. It was showed that 0.2, 0.4, and 0.8 mg mL-1 hawthorn vitexin could significantly repair hepatocyte growth and ethanol-induced DNA damage. This effect was closely related to the improvement in superoxide dismutase, malonaldehyde, and glutathione peroxidase. Hawthorn vitexin could be used to repair ethanol-injured hepatocytes through antioxidation effects, and showed potential for the treatment of liver injury.

Distribution and Potential Ecological Risk of Heavy Metals in Water, Sediments, and Aquatic Macrophytes: A Case Study of the Junction of Four Rivers in Linyi City, China.

The Yi River, the second longest river in Shandong Province, China, flows through Linyi City and is fed by three tributary rivers, Beng River, Liuqing River, and Su River in the northeastern part of the city. In this study, we determined the concentrations of five heavy metals (Cr, Ni, Cu, Zn, and Pb) in water, sediment, and aquatic macrophyte samples collected from the junction of the four rivers and evaluated the potential ecological risk of heavy metal pollution. Most of the heavy metals in water were in low concentrations with the water quality index (WQI) below 1, suggesting low metal pollution. The sediments showed low heavy metal concentrations, suggesting a low ecological risk based on the potential ecological risk index (RI) and the geo-accumulation index (Igeo). The aquatic plant species Potamogeton crispus accumulated considerable amounts of heavy metals, which were closely related to the metal concentrations of the sediment. The plant species Salvinia natans also showed an excellent metal accumulation capability. Based on our results, the junction of the four rivers is only slightly polluted in terms of heavy metals, and the plant species P. crispus is a suitable bioindicator for sediment heavy metal pollution.