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Simple Summary: To better protect and manage the germplasm resources of the topmouth culter (Culter alburnus), it is important to explore the current status of its genetic diversity. In this study, the mitochondrial DNA COI gene was used to analyze the genetic diversity, genetic differentiation, and historical dynamics of C. alburnus from five river basins in north and south China. The results showed that the genetic diversity is polarized in different populations but without new species differentiation and has significant geographical features, which are important for developing conservation strategies. To study the genetic diversity of Culter alburnus (C. alburnus) populations, we analyzed the genetic diversity of five C. alburnus populations from Songhua Lake (SH), Huaihe River (HH), Changjiang River (CJ), Taihu Lake (TH), and Gehu Lake (GH) based on mitochondrial COI gene sequences. The results showed that the average contents of bases T, C, A, and G in the 526 bp COI gene sequence were 25.3%, 18.1%, 28.1%, and 28.6%, respectively, which showed AT bias. A total of 115 polymorphic sites were detected in the five populations, and 11 haplotypes (Hap) were defined. The nucleotide diversity (Pi) of the five populations ranged from 0.00053 to 0.01834, and the haplotype diversity (Hd) ranged from 0.280 to 0.746, with the highest genetic diversity in the TH population, followed by the SH population, with lower genetic diversity in the HH, CJ and GH populations. The analysis of the fixation index (Fst) and the genetic distance between populations showed that there was significant genetic differentiation between the SH population and the other populations, and the genetic distances between all of them were far; the genetic diversity within populations was higher than that between populations. Neutral tests, mismatch distributions, and Bayesian skyline plot (BSP) analyses showed that the C. alburnus populations have not experienced population expansion and are relatively stable in historical dynamics. [ABSTRACT FROM AUTHOR]

Background and objective: Psychological stress causes structural and metabolic dysfunction of masseter muscles. The anti‐inflammatory and anti‐oxidative polyphenol curcumin plays a local antioxidant role in rat masseter muscles under psychological stress by an as‐yet‐unknown mechanism. The present study aimed to assess curcumin anti‐inflammatory and anti‐oxidative effects on masseter muscle and its possible molecular mechanisms. Methods: We constructed a rat model of chronic unpredictable moderate stress (CUMS). Psychological stress was assessed by determining the levels of adrenocorticotropic hormone (ACTH) and cortisol in serum. Enzyme‐linked immunosorbent assays measured inflammatory cytokines and markers of oxidative stress in masseter muscles. Levels of high‐mobility group box 1 (HMGB1), interleukin (IL)‐1β, IL‐6 and tumour necrosis factor‐alpha (TNF‐α) were determined using quantitative PCR analyses and immunofluorescent staining. Toll‐like receptor 4 (TLR4) and nuclear factor kappa B (NF‐κB) activation were examined using western blotting. Results: The CUMS group showed increased serum cortisol and ACTH levels. Pathological changes in the ultrastructure, oxidative stress and inflammatory cytokines in the masseter muscles were also observed. Curcumin treatment (50, 100 mg/kg) ameliorated these changes significantly by varying degrees. Mechanistically, increased levels of phosphorylated NF‐κB, toll‐like receptor 4 and HMGB1 were observed, which were also ameliorated by curcumin treatment. Conclusion: Curcumin can reduce local pathological changes, levels of oxidative stress and inflammatory factors in masseter muscles. Psychological stress activates HMGB1 expression and increases the expression of downstream TLR4 and p‐NF‐κB, which could be reduced by curcumin. Thus, curcumin might exert anti‐inflammatory and antioxidant effects in masseter muscles via the HMGB1/TLR4/NF‐κB pathway. [ABSTRACT FROM AUTHOR]