Population aging has become a major challenge for the healthcare in China. More than 23 million Chinese are cur- rently ≥ 80 years, with an annual increase of 5%. The Chi- nese population of 80 years or older is expe...Population aging has become a major challenge for the healthcare in China. More than 23 million Chinese are cur- rently ≥ 80 years, with an annual increase of 5%. The Chi- nese population of 80 years or older is expected to reach 30.67 million by 2020 and 74 million by 2040.展开更多
The effects of sublethal doses （LD10：1.00 ng larval-1; LD30： 3.75 ng larva-1） of chlorfluazuron on number and size of developmental spermatocytes in pupal-testis during spermatogenesis of the common cutworm, Spodo...The effects of sublethal doses （LD10：1.00 ng larval-1; LD30： 3.75 ng larva-1） of chlorfluazuron on number and size of developmental spermatocytes in pupal-testis during spermatogenesis of the common cutworm, Spodoptera litura （F.） are described. Chlorfluazuron was applied topically to newly-ecdysed fifth-instar larvae of S. litura under laboratory conditions. During first day of pupation, spermatids were the highest （3,430 ± 7）, however, elongated spermatocytes with mature sperm were the lowest （292 ± 16） in number in pupal-testis compared with other developing spermatocytes. During last day of pupation, elongated spermatocytes with mature sperm were the highest （3,581 ± 3）, however, spermatogonia were the lowest （86± 4） in number in pupal-testis compared with other developing spermatocytes. The number of spermatogonia, primary and secondary spermatocytes, spermatids and elongated cysts with mature sperm were increased during pupal-developmental days in the controls. However, their numbers were significantly reduced in LD10- and even more significantly reduced in LD30-treated pupal-testis compared with controls. Moreover, eupyrene sperm bundles were not present in pupal-testis. During pupal-developmental days, spermatids were the smallest （4.1 ± 0.9 dm in μm） and secondary spermatocytes were the largest （31.0 ± 1.8 dm in μm） in size compared with other developing spermatocytes. The sizes of the same developing spermatocytes were significantly reduced in LD10-treated and more significantly reduced in LD30-treated pupal-testis of S. litura compared with controls.展开更多
Human influenza viruses preferentially bind to sialic acid-α2,6-galactose (SAα2,6Gal) receptors, which are predominant in human upper respiratory epithelia, whereas avian influenza viruses preferentially bind to SA...Human influenza viruses preferentially bind to sialic acid-α2,6-galactose (SAα2,6Gal) receptors, which are predominant in human upper respiratory epithelia, whereas avian influenza viruses preferentially bind to SAα2,3Gal receptors. However, variants with amino acid substitutions around the receptor-binding sites of the hemagglutinin (HA) protein can be selected after several passages of human influenza viruses from patients’ respiratory samples in the allantoic cavities of embryonated chicken eggs. In this study, we detected an egg-adapted HA S190R mutation in the pandemic H1N1 virus 2009 (pdmH1N1), and evaluated the effects of this mutation on receptor binding affinity and pathogenicity in mice. Our results revealed that residue 190 is located within the pocket structure of the receptor binding site. The single mutation to arginine at position 190 slightly increased the binding affinity of the virus to the avian receptor and decreased its binding to the long human α2,6-linked sialic acid receptor. Our study demonstrated that the S190R mutation resulted in earlier death and higher weight loss in mice compared with the wild-type virus. Higher viral titers at 1 dpi (days post infection) and diffuse damage at 4 dpi were observed in the lung tissues of mice infected with the mutant virus.展开更多
The reproductive system of human female exhibits a much faster rate of aging than other body systems.Ovarian aging is thought to be dominated by a gradual decreasing numbers of follicles,coinciding with diminished qua...The reproductive system of human female exhibits a much faster rate of aging than other body systems.Ovarian aging is thought to be dominated by a gradual decreasing numbers of follicles,coinciding with diminished quality of oocytes.Menopause is the final step in the process of ovarian aging.This review focuses on the mechanisms underlying the ovarian aging involving a poor complement of follicles at birth and a high rate of attrition each month,as well as the alternated endocrine factors.We also discuss the possible causative factors that contribute to ovarian aging,e.g.,genetic factors,accumulation of irreparable damage of microenvironment,pathological effect and other factors.The appropriate and reliable methods to assess ovarian aging,such as quantification of follicles,endocrine measurement and genetic testing have also been discussed.Increased knowledge of the ovarian aging mechanisms may improve the prevention of premature ovarian failure.展开更多
The efforts of many laboratories worldwide and large scale international mutagenesis consortia have resulted in mutagenesis of nearly all mouse genes, and present efforts are devoted to large scale phenotyping of germ...The efforts of many laboratories worldwide and large scale international mutagenesis consortia have resulted in mutagenesis of nearly all mouse genes, and present efforts are devoted to large scale phenotyping of germline null mutant mice (Ayadi et al., 2012). Although early lethality associated with loss of function of a given gene may prevent elucidating its function at a later stage or in a given tissue, conditional alleles in which a critical part of the gene is flanked by recombinase target sites provide an opportunity for addressing gene function at later stages (Branda and Dymecki,2004). Fortunately, many of the mutant alleles generated by the consortia allow for conditional mutagenesis using site directed recombinases.展开更多
文摘Population aging has become a major challenge for the healthcare in China. More than 23 million Chinese are cur- rently ≥ 80 years, with an annual increase of 5%. The Chi- nese population of 80 years or older is expected to reach 30.67 million by 2020 and 74 million by 2040.
文摘The effects of sublethal doses （LD10：1.00 ng larval-1; LD30： 3.75 ng larva-1） of chlorfluazuron on number and size of developmental spermatocytes in pupal-testis during spermatogenesis of the common cutworm, Spodoptera litura （F.） are described. Chlorfluazuron was applied topically to newly-ecdysed fifth-instar larvae of S. litura under laboratory conditions. During first day of pupation, spermatids were the highest （3,430 ± 7）, however, elongated spermatocytes with mature sperm were the lowest （292 ± 16） in number in pupal-testis compared with other developing spermatocytes. During last day of pupation, elongated spermatocytes with mature sperm were the highest （3,581 ± 3）, however, spermatogonia were the lowest （86± 4） in number in pupal-testis compared with other developing spermatocytes. The number of spermatogonia, primary and secondary spermatocytes, spermatids and elongated cysts with mature sperm were increased during pupal-developmental days in the controls. However, their numbers were significantly reduced in LD10- and even more significantly reduced in LD30-treated pupal-testis compared with controls. Moreover, eupyrene sperm bundles were not present in pupal-testis. During pupal-developmental days, spermatids were the smallest （4.1 ± 0.9 dm in μm） and secondary spermatocytes were the largest （31.0 ± 1.8 dm in μm） in size compared with other developing spermatocytes. The sizes of the same developing spermatocytes were significantly reduced in LD10-treated and more significantly reduced in LD30-treated pupal-testis of S. litura compared with controls.
基金supported by the National Key Research and Development Program of China(2016YFC1200201 to Yuelong Shu)the National Mega-projects for Infectious Diseases(2014ZX10004002002 to Yuelong Shu)the young scientist fund of Chinese Center for Disease Control and Prevention(2016A103 to Wenfei Zhu)
文摘Human influenza viruses preferentially bind to sialic acid-α2,6-galactose (SAα2,6Gal) receptors, which are predominant in human upper respiratory epithelia, whereas avian influenza viruses preferentially bind to SAα2,3Gal receptors. However, variants with amino acid substitutions around the receptor-binding sites of the hemagglutinin (HA) protein can be selected after several passages of human influenza viruses from patients’ respiratory samples in the allantoic cavities of embryonated chicken eggs. In this study, we detected an egg-adapted HA S190R mutation in the pandemic H1N1 virus 2009 (pdmH1N1), and evaluated the effects of this mutation on receptor binding affinity and pathogenicity in mice. Our results revealed that residue 190 is located within the pocket structure of the receptor binding site. The single mutation to arginine at position 190 slightly increased the binding affinity of the virus to the avian receptor and decreased its binding to the long human α2,6-linked sialic acid receptor. Our study demonstrated that the S190R mutation resulted in earlier death and higher weight loss in mice compared with the wild-type virus. Higher viral titers at 1 dpi (days post infection) and diffuse damage at 4 dpi were observed in the lung tissues of mice infected with the mutant virus.
基金supported by the National Basic Research Program of China (Grant Nos. 2012CB944402,2011CB944501 and 2007CB947401)Program of Knowledge Innovation of Chinese Academy of Sciences (GrantNo. KSCX2-EW-R-07)
文摘The reproductive system of human female exhibits a much faster rate of aging than other body systems.Ovarian aging is thought to be dominated by a gradual decreasing numbers of follicles,coinciding with diminished quality of oocytes.Menopause is the final step in the process of ovarian aging.This review focuses on the mechanisms underlying the ovarian aging involving a poor complement of follicles at birth and a high rate of attrition each month,as well as the alternated endocrine factors.We also discuss the possible causative factors that contribute to ovarian aging,e.g.,genetic factors,accumulation of irreparable damage of microenvironment,pathological effect and other factors.The appropriate and reliable methods to assess ovarian aging,such as quantification of follicles,endocrine measurement and genetic testing have also been discussed.Increased knowledge of the ovarian aging mechanisms may improve the prevention of premature ovarian failure.
基金supported by grants RO1 DE022363 and RO1 DE022778 from the National Institute of Dental and Craniofacial Research
文摘The efforts of many laboratories worldwide and large scale international mutagenesis consortia have resulted in mutagenesis of nearly all mouse genes, and present efforts are devoted to large scale phenotyping of germline null mutant mice (Ayadi et al., 2012). Although early lethality associated with loss of function of a given gene may prevent elucidating its function at a later stage or in a given tissue, conditional alleles in which a critical part of the gene is flanked by recombinase target sites provide an opportunity for addressing gene function at later stages (Branda and Dymecki,2004). Fortunately, many of the mutant alleles generated by the consortia allow for conditional mutagenesis using site directed recombinases.
