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Articles by Yongfeng Sun
Total Records ( 4 ) for Yongfeng Sun
  Lu Chen , Kangle Yi , Yongfeng Sun , Yanling Sun , Lina Tang and Xu Zhou
  Neurotrophins (NTs) belong to a family of soluble homodimeric polypeptide growth factors and are widely recognized for their essential roles in central and peripheral nervous systems. One such neurotrophin, Brain-Derived Neurotrophic Factor (BDNF) was originally described in the nervous system but has now been shown to be expressed in reproductive system. In this study, the researchers examined the presence and different expression levels of BDNF mRNA in porcine reproductive organs during different stages of estrous cycle and in pig oocytes in Germinal Vesicle (GV) and in vitro matured Metaphase II (MII) stage. In oviduct and uterus, BDNF mRNA expression was higher than that in ovary (p<0.05). The expression level in luteal phase ovary is higher than that in follicular phase ovary but the difference between them was not significant (p>0.05), a similar but more significant change occurred in oviduct (p<0.05). However, the expression levels in uterus were on an opposite trend i.e., a higher level of mRNA for BDNF was found in follicular phase uterus instead of in luteal phase uterus. BDNF mRNA was also detected in GV oocytes and in vitro matured MII oocytes with significantly higher amounts in GV oocytes than in MII oocytes (p<0.01). These results suggest a possible role for BDNF in the regulation and modulation of pig reproductive function and oocyte maturation.
  Lina Tang , Lu Chen , Chunjin Li , Yongfeng Sun , Yanling Sun and Xu Zhou
  The development of reproductive system in prepubertal gilts was affected not only by gonadotropins but also by other cytokines and growth factors. Recent studies have revealed that Neurotrophins (NTs) which are well known for their essential roles in neural system also expressed in mammalian reproductive organs and involved in the regulation of mammalian reproduction. Dietary energy level is an important factor affecting domestic animal reproductive performance including central effects on Hypothalamic Pituitary Gonadal (HPG) axis and local effects on gonads. In the present study, the expression of Neurotrophin-4 (NT-4) which is a member of NTs in reproductive tissues of prepubertal gilts including ovary, oviduct and uterus was studied by immunohistochemistry. The effects of dietary energy on NT-4 mRNA expression were also investigated by quantitative PCR. The results show that NT-4 was localized in all classes of follicles in ovaries of prepubertal gilts including primordial follicles, primary follicles and secondary follicles, NT-4 was localized in mucosal epithelial cells in oviducts and glandular epithelium and endometrial epithelium in uteri. Furthermore, different dietary energy levels altered mRNA expression level of NT-4 in ovaries, uteri and oviducts of prepubertal gilts. NT-4 mRNA expression level in ovaries and uteri was higher in high dietary energy group than that in mid and low-energy groups. In oviduct, the expression pattern of NT-4 mRNA among three different dietary energy groups is similar as that occurred in in ovaries and uteri but with more significant differences. These results suggest that NT-4 may be one of the signals that links metabolic status and neuroendocrine control of reproduction in pig.
  Yongfeng Sun , Tongao Yang , Jingtao Hu , Zhe Hao , Yujian Sui , Yingying Fu , Lu Chen , Haiyang Zhu and Wei Wu
  The muscular tissue of breast was dissected from 8 weeks old Jilin White goose in the present study. The big fragment PCR Method was used to amplify double-strand cDNA based on the SMART techniques for construction of a full-length cDNA library. After digestion with restriction endonuclease Sfi |, a modified vector of pBluescript II SK-plasmid with the adaptors containing Sfi |A and Sfi |B sites was used to recombine with the cDNA products amplified. The recombinants were cloned by transformation into competent Escherichia coli DH2α. A plasmid cDNA library with goose muscle was constructed. The results showed that the titer of the cDNA library was 1.01x106 pfu mL-1 and the percentage of recombinant clones was 97%. The length of most cDNA inserted was between 0.25 and 1.6 kb identified by gel electrophoresis after cDNA PCR amplification. The unigene ratio was 66.7% and the percentage of complete cDNA sequences was 80% by estimating from the 24 clones sequenced randomly. It is helpful to study muscle development of goose at molecular level in the future.
  Yongfeng Sun , Zhe Hao , Yujian Sui , Lifeng Zhao and Guang Gao
  In this study, researchers detected the expression of IGF-I mRNA at 1 (day 1), 30 (day 30), 60 (day 60th) and 90 (day 90th) days of age in the breast muscle and leg muscle of geese from Jilin White goose (meat type, egg type) and Hortobagyi goose. Researchers found that the expression of IGF-I mRNA in skeletal muscle tissues differed based on developmental age. The expression of IGF-I mRNA exhibited a trend that ascended firstly and then descended after birth. IGF-I mRNA was expressed in all breast muscle tissues during each stage with higher levels in meat type goose and Hortobagyi goose than that in Jilin egg type goose (p<0.05). The expression pattern of IGF-I mRNA in breast muscle of meat type goose was similar with this in and Hortobagyi goose and in leg muscle, IGF-I mRNA expression patterns were all down-regulated from day 30. Similarity in IGF-I mRNA expression pattern were found in breast among Jilin meat type goose, egg type goose and Hortobagyi goose which indicates that IGF-I may be related to skeletal muscle differentiation and growth and suggests IGF-I mRNA maybe tissue-specific expression and individual difference.
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