RESUMO
Objective To investigate the effects of dams-offspring separation on anxiety-like behaviors of dams, and if these anxiety-like behaviors of dams are associated with estrogen receptorα(ERα) and β( ERβ)in some brain regions. Methods Thirty C57BL/6 J female mice were divided into three groups, control group (CG, n= 10,non-isolated group), short-term separation group( SG,/i= 10, dams were separated from their offspring for 15 minuts per day from the second day to the tenth day after childbirth ) and long-term separation group ( LG, n = 10, dams were separated from their offspring for 3 hours per day from the second day to the tenth day after childbirth ). Anxiety-like behaviors of dams were evaluated in an open-field (OF) and elevated plus-maze test ( EPM ). The level of ERα- immunoreactive neurons (ERα-IRs) and ERβ-immunoreactive neurons (ERβ-IRs) in three brain regions including medial preoptic area (mPOA), hypothalamic ventromedial nucleus (VMH) and medial amygdaloid nucleus ( MeA) were analyzed. Results In OF, compared to CG group and SG group, LG group had significantly less time in center area, crossing number and total distance(P0.05 ). In EPM, compared to CG group and SG group, LG group had significantly less percentage of time, distance in open arms and total distance(P<0.001 ). Compared to CG group and SG group, LG group had significantly less ERa-IRs and ERβ-IRs in mPOA, VMH, and MeA(P<0.01). Conclusion Dams that are long-termly separated from their offspring may have anxiety-like behavior, and this behavior may be related to the significant reduction of ERa and ERβ in these brain regions.
RESUMO
BACKGROUND: Procambarus clarkii produces high-quality, delicious meat that is high in protein, low in fat, and rich in calcium and phosphorus. It has become an important aquatic resource in China. Our objectives are (i) to analyze the level of genetic diversity of P. clarkii populations; (ii) to explore the genetic differentiation (Gst); and (iii) to propose appropriate strategies for the conservation. RESULTS: In this study, Shannon's index (I) and Nei's gene diversity index (H) for P. clarkii were high (I = 0.3462 and H = 0.2325 on average and I = 0.6264, H = 0.4377 at the species level) based on the SSR markers. The expected heterozygosity value of 17 microsatellite loci in 25 crayfish populations was 0.9317, the observed heterozygosity value was 0.9121, and the observed number of alleles per locus was 2.000; and the effective number of alleles per locus was 1.8075. Among the P. clarkii populations, the inbreeding coefficient within populations (Fis) was 0.2315, overall inbreeding coefficient (Fit) was 0.4438, genetic differentiation coefficient among populations (Fst) was 0.3145 and gene differentiation (Gst) was 0.4785 based on SSR analyses. The cluster analysis results obtained by unweighted pair-group method with arithmetic mean (UPGMA) analysis, principal coordinate analysis (PCoA) and STRUCTURE analysis were similar. A mantel test showed that the isolation-by-distance pattern was not significant. CONCLUSIONS: The high Gst among P. clarkii populations is attributed to genetic drift and geographic isolation. The results indicated that more P. clarkii populations should be collected when formulating conservation and aquaculture strategies.