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Paraquat (PQ), a broad‐spectrum agricultural pesticide, causes cellular toxicity by increasing oxidative stress levels in various biological systems, including the reproductive system. PQ exposure causes embryotoxicity and reduces the developmental abilities of embryos. However, there is little information regarding the toxic effects of PQ on oocyte maturation. In this study, we studied the toxic effects of PQ exposure and the effects of melatonin on PQ‐induced damage in bovine oocytes. PQ exposure disrupted nuclear and cytoplasmic maturation, which was manifested as decreased cumulus cell expansion, reduced first polar body extrusion, and abnormal distribution patterns of cortical granules and mitochondria. In addition, PQ treatment severely disrupted the ability of the resulted in vitro‐produced embryos to develop to the blastocyst stage. Moreover, PQ exposure significantly increased the intracellular reactive oxygen species (ROS) level and early apoptotic rate, and decreased the glutathione (GSH) level, antioxidative CAT and GPx4 mRNA, and apoptotic‐related Bcl-2/Bax mRNA ratio. These results indicated that PQ causes reproductive toxicity in bovine oocytes. Melatonin application resulted in significant protection against the toxic effects of PQ in PQ‐exposed oocytes. The mechanisms underlying the role of melatonin included the inhibition of PQ‐induced p38 mitogen‐activated protein kinase (MAPK) activation, and restoration of abnormal trimethyl‐histone H3 lysine 4 (H3K4me3) and trimethyl‐histone H3 lysine 9 (H3K9me3) levels. These results reveal that melatonin serves as a powerful agent against experimental PQ‐induced toxicity during bovine oocyte maturation and could form a basis for further studies to develop therapeutic strategies against PQ poisoning. [ABSTRACT FROM AUTHOR]

Lipopolysaccharide disturbs the secretion of gonadotropin, endometrial function and implantation efficiency. However, there is little information regarding the effects of lipopolysaccharide on cyclic ovary activity, especially oocyte maturation. Therefore, we aimed to investigate the effects of lipopolysaccharide on the maturation potential of bovine oocytes. We found that lipopolysaccharide exposure significantly decreased the first polar body extrusion rate and delayed the cell cycle progression. The abnormal spindle rate was significantly increased in lipopolysaccharide treatment group, accompanied by disrupted localization and level of phosphorylated mitogen-activated protein kinase (p-MAPK). Moreover, lipopolysaccharide treatment significantly increased intracellular reactive oxygen species (ROS) levels and the early apoptotic rate in oocytes. The pro-apoptotic caspase-3 and Bax mRNA levels and caspase-3 protein level were significantly increased, whereas the anti-apoptotic Bcl-2 and XIAP transcript abundance were significantly decreased in lipopolysaccharide exposure group. Furthermore, the dimethyl-histone H3 lysine 4 (H3K4me2) level was significantly increased, while the DNA methylation (5-mC) and dimethyl-histone H3 lysine 9 (H3K9me2) levels were markedly decreased in oocytes treated with lipopolysaccharide. In conclusion, lipopolysaccharide exposure inhibits the maturation potential of bovine oocytes by affecting cell cycle, cytoskeletal dynamics, oxidative stress, and epigenetic modifications.

The process of differentiated somatic cells to a pluripotent state or to another unrelated cell type is referred to as cellular reprogramming. This can be achieved through somatic cell nuclear transfer, cell fusion, specific transcription-factor transduction, and exposure to cell extracts. Cellular reprogramming using cell extracts has gained increasing attention in recent years and has been applied to acquire the target cell types, recognize the functional factors, explore the reprogramming mechanism. In this review, we described different methods of reprogramming somatic cells, which mainly focused on the advances in cellular reprogramming using cell extracts.

The epidermal growth factor receptor (EGFR), a transmembrane protein receptor, is a member of ErbB family with signal-transducing tyrosine kinase activity. After combined with the ligand, EGFR homologous or heterologous dimers are formed to induce intracellular signal transduction, activate downstream signal transduction pathways, and then produce a series of biological effects. RAF/MEK/RAS/ERK pathway is relevant to cell proliferation, differentiation and apoptosis; while PDK1/AKT /PI3K pathway is involved in cell migration and adhesion. EGFR can promote the maturity of pulmonary type II epithelial cells and the synthesis and secretion of pulmonary surfactant. EGFR shows the effect on mammal lungs in a time-space and dose-dependent manner. The down-regulated expression of it will lead to immature lung development, while the over-expression can promote the cell proliferation, invasion and metastasis of the lung cancer cells. This paper reviewed advances in the study for EGFR and its signal pathway, as well as the relationship among EGFR, atelectasis and lung cancer.

Transgenic technology represents a revolutionary way to produce elite livestock breeds, allowing introduction of alien gene into livestock genome. Currently, pronuclear microinjection of DNA and somatic cell nuclear transfer are two popular methods used to make transgenic farm animals. Transgenic technology can be used in livestock breeding for improving disease resistance, carcass composition, lactational performance, wool production, growth rate, and reproductive performance, as well as reducing negative environmental impact. In addition to introduction of animal transgenic technologies, this review described the status and the future perspective of transgenic breeding in livestock.

In this review of methods for purity assessment of isolated chromosome X- and Y-bearing sperm, we compared the principles, operating procedures, as well as pros and cons for various methods. We conclude that nested PCR of single sperm will become a conventional and popular method with lower costs, and the method will play a very important role in optimizing the X, Y sorting method, if the sensitivity and accuracy of the method can be increased and the testing time decreased, and promote the new progress in other genetic testing techniques on single sperm.

The developmental competence of embryos cloned from somatic cells depends on the cellular event and molecular process, such as separation of chromosomes and reorganization of spindle after nuclear transfer. Centrosome, the main microtubule organizing centers in a cell, is crucial for reorganization of spindle and normal separation of chromosomes during mitosis. Aberrant of centrosomes will lead to aneuploidy of blastomere and developmental failure of embryo. This paper expounded the situation of animal somatic cell nuclear transfer (SCNT) and biological functions of centrosome and analyzed the inheritance mechanism of centrosome during gametogenesis and fertilization. Additionally, the study condition of centrosome and its associated proteins in SCNT embryos were introduced, which provided a new clue to study the de-velopmental abnormality of cloned embryos and animals.

In order to investigate Sry regulation network in the development of male embryo, we inhibited the Sry gene expression by RNAi and then examined expression of other sex-related genes. Six genes (Sox9, Wt1, Sf1, Dax1, Gata4 and Amh), which are suggested to be closely related to Sry regulation were studied. Two siRNA expression vectors pSilencer4.1/Sry217 and pSilencer4.1/Sry565 were constructed and injected into gestated mouse through tail vein at 9.5 day of conception (dpc). The inhibition efficiency of Sry and the expression of other six genes were examined in male embryos at 11.5 dpc by RT-PCR and Western-blot. Expressions of the other six genes were analyzed by fluorescence quantity PCR. The results indicated both the pSilencer4.1/Sry217 and pSilencer4.1/Sry565 could inhibit significantly increased after Sry silencing. In contrast, no significant changes were observed in the expression of Sf1, Amh, Gata4, Dax1 and Sox9 when silencing Sry by siRNA. Our results suggested that the Wt1 transcription was regulated by Sry, whereas the Sox9 expression is not directly regulated by Sry in the development of genital ridge.

Complex vertebral malformation (CVM), a lethal autosomal recessive inherited defect in Holstein breed, was newly reported in Demark. If the proportion of CVM carriers in the nucleus breeding group of Holstein is high, great economic losses to dairy industry would be caused by the death of affected homozygous fetuses and the abortion of pregnant cows. The main symptoms and some important influences of CVM to dairy industry were reviewed, The process of researches on the CVM and the testing methods were explicated, and the status of potential CVM carriers in China was also discussed.