Transcriptomics reveals the mechanism of selenium-enriched Lactobacillus plantarum alleviating brain oxidative stress under cadmium stress in Luciobarbus capito.

Cadmium (Cd) is one of toxic metal in environment and is thought to affect nervous system. There were an increasing number of studies on selenium (Se)-enriched probiotics which were believed to produce bioactive nanoselenium. The antagonism of Se on heavy metals can significantly affect biological toxicity of heavy metals. This study aimed to elucidate possible mechanism of brain injury in Luciobarbus capito after Cd exposure and the mitigation of Se-enriched probiotics through transcriptome analysis. The results revealed 465 differentially expressed genes in the Cd and the control brains (Cd vs C), including 320 genes with upregulated expression and 145 genes with downregulated expression. In addition, we found that there were 4117 differentially expressed genes in the Se-enriched L. plantarum plus Cd and the control brains (S1L1-Cd vs C), including 2552 genes with upregulated expression and 1565 genes with downregulated expression. There were 147 differentially expressed genes in the Se-enriched L. plantarum plus Cd and the control brains (S1L1-Cd vs Cd), including 40 genes with upregulated expression and 107 genes with downregulated expression. Moreover, GO enrichment analysis indicated that the differentially expressed genes were involved in biological processes cellular component, and molecular function. KEGG enrichment analysis indicated that MAPK signaling pathway, calcium signaling pathway, and PI3K-Akt signaling pathway were significantly enriched. Subsequently, qRT-PCR was performed, and we selected 15 related differentially expressed genes for verification. The qRT-PCR results revealed the same trend as the RNA-Seq results. In conclusion, this study elucidated relieving effect of Se-enriched probiotics on Cd exposure-induced brain oxidative stress. This study provided a theoretical basis for further research on genes related to Cd poisoning and the amelioration of Se-enriched probiotics on Cd poisoning.

Influence of environmental variables on macroinvertebrate community structure in Lianhuan Lake.

The structural characteristics of the macroinvertebrate community can effectively reflect the health status of lake ecosystems and the quality of the lake ecological environment. It is therefore important to identify the limiting factors of macroinvertebrate community structure for the maintenance of lake ecosystem health. In this study, the community composition of macroinvertebrate assemblages and their relationships with environmental variables were investigated in 13 small lakes within Lianhuan Lake in northern China. A self-organizing map and K-means clustering analysis grouped the macroinvertebrate communities into five groups, and the indicator species reflected the environmental characteristics of each group. Principal component analysis indicated that the classification of the macroinvertebrate communities was affected by environmental variables. The Kruskal-Wallis test results showed that environmental variables (pH, total phosphorus, nitrate, water temperature, dissolved oxygen, conductivity, permanganate index, and ammonium) had a significant effect on the classification of the macroinvertebrate communities. Redundancy analysis showed that mollusks were significantly negatively correlated with pH and chlorophyll a, while annelids and aquatic insects were significantly positively correlated with chlorophyll a and dissolved oxygen. Spearman correlation analysis showed that the species richness and Shannon's diversity of macroinvertebrates were significantly negatively correlated with total phosphorus, while the biomass of macroinvertebrates was significantly negatively correlated with pH. High alkalinity and lake eutrophication have a serious impact on the macroinvertebrate community. Human disturbances, such as industrial and agricultural runoff, negatively impact the ecological environment and affect macroinvertebrate community structure. Thus, macroinvertebrate community structure should be improved by enhancing the ecological environment and controlling environmental pollution at a watershed scale.