Glutathione S-transferase A1 (GSTA1) release,an early indicator of acute hepatic injury in mice

Three acute hepatic injury models (a CCl₄-induced model, APAP-induced model and ethanol-induced model) in mice were used to study the importance of GSTA1 in acute hepatic injury by comparison with a standard enzyme marker, alanine aminotransferase (ALT). GSTA1 release was demonstrated to be an earlier and more sensitive indicator of hepatotoxicity than was ALT. Significant increases in GSTA1 were detected at 2 h after CCl₄ exposure, while ALT was undetected at this time. GSTA1 was also a more sensitive indicator of hepatotoxicity than ALT after 6 h. In the APAP and ethanol models, GSTA1 was markedly increased earlier than ALT, at 2 h post exposure. The release of GSTA1 was significantly increased at a dose of 12.5 mg/kg (CCl₄ model), 100 mg/kg (APAP model) and 10 ml/kg (ethanol model), the lowest exposure concentration for each model. In contrast, AST release was not statistically significant. These results suggest that GSTA1 can be detected at low concentrations during the early stages of acute hepatic injury and that GSTA1 is a more sensitive and more accurate indicator than ALT.     

Estimation of bisphenol A (BPA) concentrations in pregnant women,fetuses and nonpregnant women in Eastern Townships of Canada

We determined bisphenol A (BPA) concentrations of 61 pregnant women (PW), their fetuses and 26 nonpregnant women (NPW) in Eastern Townships of Canada; and evaluated potential correlations between maternal and fetal blood, and between peripheral blood and peritoneal fluid. In PW, BPA levels were ranged from non-detected to 4.46 ng/ml and from non-detected to 4.60 ng/ml for maternal and fetal serum, respectively. In NPW, BPA levels were ranged from 1.30 to 8.17 ng/ml and from 0.19 to 13.45 ng/ml for serum and peritoneal fluid, respectively. Positive correlation was found between maternal and fetal serum, and between serum and peritoneal fluid. In conclusion, our findings highlight a continuous distribution of BPA between the mother and its fetus and reveal a role of pregnancy in underestimating the actual levels of blood BPA. Our study also provides a temporal-spatial reference on BPA exposure, which is a useful tool in monitoring, comparing and correcting.     

Melatonin promotes the in vitro development of pronuclear embryos and increases the efficiency of blastocyst implantation in murine

When a defect occurs in the in vitro development of a pronuclear embryo, the interruption of the subsequent implantation limits the success of assisted conception. This common problem remains to be solved. In this study, we observed that melatonin at its physiological concentration (10^?7 m ) significantly promoted the in vitro development of murine pronuclear embryos. This was indicated by the increased blastocyst rate, hatching blastocyst rate, and blastocyst cell number with melatonin treatment. In addition, when these blastocysts were implanted into female recipient mice, the pregnancy rates (95.0% versus control 67.8%), litter sizes (4.1 pups/litter versus control 2.7 pups/litter), and postnatal survival rates of offspring (96.84% versus control 81.24%) were significantly improved compared with their non‐melatonin‐treated counterparts. Mechanistic studies revealed that melatonin treatment upregulates gene expression of the antioxidant enzyme, superoxide dismutase (SOD), and the anti‐apoptotic factor bcl‐2 while downregulating the expression of pro‐apoptotic genes p53 and caspase‐3. Due to these changes, melatonin treatment reduces ROS production and cellular apoptosis during in vitro embryo development and improves the quality of blastocysts. The implantation of blastocysts with higher quality leads to more healthy offspring and increased pup survival.     

Genomic sequence comparison,promoter activity,SNP detection of RIG-I gene and association with resistance/susceptibility to grass carp reovirus in grass carp (Ctenopharyngodon idella)

As an intracellular pattern recognition receptor (PRR), retinoic acid-inducible gene-I (RIG-I) is responsible for detection of nucleic acids from pathogens in infected cells and activation of type I interferon (IFN). In the present study, the 5′-flanking region, introns and single nucleotide polymorphisms (SNPs) of CiRIG-I (Ctenopharyngodon idella RIG-I) were identified and characterized. The genomic CiRIG-I was 12810 bp in length, consisted of an 1864 bp 5′-flank region whose promoter activity was confirmed, 15 exons and 14 introns. By pooled DNA sequencing, two SNPs were detected in the 5′-flanking region; 10 SNPs were discovered in introns; and one SNP was found in exons. After a challenge experiment, these SNPs were selected to analyze their association with the resistance/susceptibility of C. idella to grass carp reovirus (GCRV), using case-control study. Chi-square test was employed to assess the association. The result showed that −780 C/T, 4731 C/T, 4945 A/G, 8461 C/T, and haplotype 3428A–3432G were significantly associated with the phenotype (P < 0.05). To confirm the correlation, another independent challenge experiment was performed, in which the cumulative mortality of −780 genotype CC, 4731 genotype CC and 4945 genotype AA were significantly lower than that of −780 genotype TT, 4731 genotype TT and 4945 genotype GG, respectively (P < 0.05). In addition, the SNP–SNP interaction analysis revealed that there was no significant interaction among those SNPs (P > 0.05). These significant SNPs and the haplotype might be potential genetic markers for the molecular selection of C. idella strains that are resistant to GCRV.     

丙酸睾酮对大肠杆菌RecQ解旋酶结构和功能的影响

目的研究体外丙酸睾酮对大肠杆菌RecQ解旋酶结构和功能的影响及二者的相互作用机制。方法分别运用荧光偏振技术、ATPase试剂盒和紫外吸收光谱技术分析丙酸睾酮对大肠杆菌RecQ解旋酶活性和DNA结合活性、AT-Pase活性和构象的影响。结果丙酸睾酮能够影响E.coliRecQ解旋酶的活性。低浓度促进解旋酶活性,高浓度抑制;抑制RecQ解旋酶与dsDNA的结合活性,其抑制常数Ki小于7×10-5 nmol.L-1;对与ssDNA结合活性的Ki为7×10-3 nmol.L-1;对ATPase活性抑制作用的时间相关性较弱;影响RecQ解旋酶的构象变化,但峰位无偏离。结论提示丙酸睾酮与RecQ解旋酶具有弱相互作用,二者具有两个结合位点。     

Melatonin‐related genes expressed in the mouse uterus during early gestation promote embryo implantation

Melatonin, a superior antioxidant, is an important molecule which regulates female reproduction due to its receptor‐mediated and receptor‐independent antioxidant actions. In this study, we investigated the effect of melatonin on early gestation in a mouse model. During early gestation, the expression of the melatonin's rate‐limiting enzyme, AANAT, gradually increased – in the uterus while the MT2 melatonin receptor was only expressed at day 2 of gestation and no MT1 was detected. Based on these findings, we conducted a melatonin injection experiment which demonstrated that 15 mg/kg melatonin significantly improved the number of implantation sites and the litter size. Also, the blastocyst and uterus were collected to identify the local action of melatonin. In the melatonin‐treated mice, the endometrium was thicker than in the control mice; melatonin also caused an increase in density of uterine glands, and the uterine gland index (UGI) was significantly elevated over that of the control. Serum steroid hormone measurements revealed that at day 6 of gestation (postimplantation), melatonin significantly downregulated the E₂ level, with no obvious effects on progesterone. Gene expression assay revealed that melatonin significantly upregulated expression of HB‐EGF, a crucial gene involved in implantation as well as its receptor ErbB1 in the blastocyst. In addition, PRA, an important gene which influences the decidual response and luminal cell differentiation, p53, which regulates uterine through leukaemia inhibitory factor (LIF), were both increased after melatonin treatment. These data suggest that melatonin and its MT2 receptor influence early gestation. Exogenous melatonin treatment can improve mouse embryo implantation and litter size, which may have important applications in human reproductive health and animal husbandry.