Aim In this study, we investigated the changes of lymphocyte subpopulationand apoptosis process of lymphocytes in the elderly, and the modulatory effect of pollen extract(PE) on apoptosis. Methods Lymphocyte phenotype...Aim In this study, we investigated the changes of lymphocyte subpopulationand apoptosis process of lymphocytes in the elderly, and the modulatory effect of pollen extract(PE) on apoptosis. Methods Lymphocyte phenotypes were detected using indirect immunofluorescencetechnique. The proliferation responses were determined by MTT method. Flow cytometry and automaticimage analysis were performed to evaluate the apoptosis of lymphocytes. Results The proliferationresponses of lymphocytes in the elderly were lower than that in young adults. Decreased CD_(45) RA^+cells and increased CD_(45) RO^+ cells were found in lymphocyte population of aged people, comparedwith that of young adults. The CD_(45) RO^+ cells were prone to apoptosis. There is an inhibitoryeffect of PE on apoptosis of lymphocytes in the elderly. Conclusion It is implied that thesusceptibility of lymphocyte in the elderly to apoptosis depends on activation, so called,activation-induced cell death. Present results suggest that apoptosis of lymphocytes in aged peopleplay an important role in the pathogenesis of immunosenescence. Thus, a possibility is open fordevelopment of apoptosis-modulating drugs from pollen.展开更多
Telomerase has fundamental roles in bypassing cellular aging and in cancer progression by maintaining telomere homeostasis and integrity. However, recent studies have led some investigators to suggest novel biochemica...Telomerase has fundamental roles in bypassing cellular aging and in cancer progression by maintaining telomere homeostasis and integrity. However, recent studies have led some investigators to suggest novel biochemical properties of telomerase in several essential cell signaling pathways without apparent involvement of its well established function in telomere maintenance. These observations may further enhance our understanding of the molecular actions of telomerase in aging and cancer. This review will provide an update on the extracurricular activities of telomerase in apoptosis, DNA repair, stern cell function, and in the regulation of gene expression.展开更多
Aims Litterfall is a key parameter in forest biogeochemical cycle and fire risk prediction.However,considerable uncertainty remains regarding the litterfall variations with forest ages.Quantifying the interannual vari...Aims Litterfall is a key parameter in forest biogeochemical cycle and fire risk prediction.However,considerable uncertainty remains regarding the litterfall variations with forest ages.Quantifying the interannual variation of forest litterfall is crucial for reducing uncertainties in large-scale litterfall prediction.Methods Based on the available dataset(N=318)with continuous multi-year(≥2 years)measurements of litterfall in Chinese planted and secondary forests,coefficient of variation(CV),variation percent(V_(P)),and the ratio of next-year litterfall to current-year litterfall were used as the indexes to quantify the interannual variability in litterfall.Important Findings The interannual variations of litterfall showed a declining trend with increasing age from 1 to 90 years.The litterfall variations were the largest in 1-10 years(mean CV=23.51%and mean V_(P)=−28.59%to 20.89%),which were mainly from tree growth(mean ratio of next-year to current-year=1.20).In 11-40 years,the interannual variations of litterfall gradually decreased but still varied widely,mean CV was~18%and mean V_(P) ranged from−17.69%to 21.19%.In 41-90 years,the interannual variations minimized to 8.98%in mean CV and~8%in mean V_(P).As a result,forest litterfall remained relatively low and constant when stand age was larger than 40 years.This result was different from the previous assumptions that forest litterfall reached relatively stable when stand age was larger than 30,20 or even 15 years.Our findings can improve the knowledge about forest litter ecology and provide the groundwork for carbon budget and biogeochemical cycle models at a large scale.展开更多
Exotic plant invasions may alter ecosystem carbon processes, especially when native plants are displaced by plants of a different functional group. Forb invasions into grasslands are common, yet little is known about ...Exotic plant invasions may alter ecosystem carbon processes, especially when native plants are displaced by plants of a different functional group. Forb invasions into grasslands are common, yet little is known about how they impact carbon cycling. We conducted a field study over 2 years from April 2010 to March 2012 in China to examine changes in soil respiration (Rsoil) following invasion of exotic perennial forb species (Alternanthera philoxeroides or Solidago canadensis) into an annual grassland dominated by a native annual graminoid (Eragrostis pilosa). Measurements of Rsoil were taken once a week in stands of the native annual graminoid or one of the forb species using static chamber-gas chromatograph method. Aboveground litterfall of each of the three focal species was collected biweekly and litter decomposition rates were measured in a 6-month litterbag experiment. The monthly average and annual cumulative Rsoil increased following invasion by either forb species. The increases in cumulative Rsoil were smaller with invasion of Solidago (36%) than Alternanthera (65%). Both invasive forbs were associated with higher litter quantity and quality (e.g., C:N ratio) than the native annum graminoid. Compared to the native annual graminoid, the invasive forbs Altevnanthera (155%) and Solidago (361%) produced larger amounts of more rapidly decomposing litter, with the litter decay constant k being 3.8, 2.0 and 1.0 for Alternanthera, Solidago and Eragrostis, respectively. Functional groups of the invasive plants and the native plants they replaced appear to be useful predictors of directions of changes in Rsoil, but the magnitude of changes in Rsoil seems to be sensitive to variations in invader functional traits.展开更多
文摘Aim In this study, we investigated the changes of lymphocyte subpopulationand apoptosis process of lymphocytes in the elderly, and the modulatory effect of pollen extract(PE) on apoptosis. Methods Lymphocyte phenotypes were detected using indirect immunofluorescencetechnique. The proliferation responses were determined by MTT method. Flow cytometry and automaticimage analysis were performed to evaluate the apoptosis of lymphocytes. Results The proliferationresponses of lymphocytes in the elderly were lower than that in young adults. Decreased CD_(45) RA^+cells and increased CD_(45) RO^+ cells were found in lymphocyte population of aged people, comparedwith that of young adults. The CD_(45) RO^+ cells were prone to apoptosis. There is an inhibitoryeffect of PE on apoptosis of lymphocytes in the elderly. Conclusion It is implied that thesusceptibility of lymphocyte in the elderly to apoptosis depends on activation, so called,activation-induced cell death. Present results suggest that apoptosis of lymphocytes in aged peopleplay an important role in the pathogenesis of immunosenescence. Thus, a possibility is open fordevelopment of apoptosis-modulating drugs from pollen.
基金Acknowledgments Research in author's lab was supported in part by a grant from the National Natural Science Foundation of China (No. 30671065), the Research Fund for the Doctoral Program of High Education (No. 20060027008), and the National Important Basic Research Project (No. 2007CB507402) to Yusheng Cong. Support from NASA grants NNJ06HD92G and NNJ05HD36G (JWS) is acknowledged.
文摘Telomerase has fundamental roles in bypassing cellular aging and in cancer progression by maintaining telomere homeostasis and integrity. However, recent studies have led some investigators to suggest novel biochemical properties of telomerase in several essential cell signaling pathways without apparent involvement of its well established function in telomere maintenance. These observations may further enhance our understanding of the molecular actions of telomerase in aging and cancer. This review will provide an update on the extracurricular activities of telomerase in apoptosis, DNA repair, stern cell function, and in the regulation of gene expression.
基金supported by the National Key Research and Development Program of China(2017YFC0503906)the China Special Fund for Meteorological Research in the Public Interest(GYHY201406034).
文摘Aims Litterfall is a key parameter in forest biogeochemical cycle and fire risk prediction.However,considerable uncertainty remains regarding the litterfall variations with forest ages.Quantifying the interannual variation of forest litterfall is crucial for reducing uncertainties in large-scale litterfall prediction.Methods Based on the available dataset(N=318)with continuous multi-year(≥2 years)measurements of litterfall in Chinese planted and secondary forests,coefficient of variation(CV),variation percent(V_(P)),and the ratio of next-year litterfall to current-year litterfall were used as the indexes to quantify the interannual variability in litterfall.Important Findings The interannual variations of litterfall showed a declining trend with increasing age from 1 to 90 years.The litterfall variations were the largest in 1-10 years(mean CV=23.51%and mean V_(P)=−28.59%to 20.89%),which were mainly from tree growth(mean ratio of next-year to current-year=1.20).In 11-40 years,the interannual variations of litterfall gradually decreased but still varied widely,mean CV was~18%and mean V_(P) ranged from−17.69%to 21.19%.In 41-90 years,the interannual variations minimized to 8.98%in mean CV and~8%in mean V_(P).As a result,forest litterfall remained relatively low and constant when stand age was larger than 40 years.This result was different from the previous assumptions that forest litterfall reached relatively stable when stand age was larger than 30,20 or even 15 years.Our findings can improve the knowledge about forest litter ecology and provide the groundwork for carbon budget and biogeochemical cycle models at a large scale.
基金supported by the National Natural Science Foundation of China (No.41225003)the Scientific Research Foundation of Jiangxi Agricultral University, China (No.09005172)+2 种基金the Program of Introducing Talents of Discipline to Nanjing Agricultural University, the China Ministry of Education (111 Project) (No.B12009)US National Science Foundation (No.DEB0820560)the Priority Academic Program Development of Jiangsu Higher Education Institutions, China
文摘Exotic plant invasions may alter ecosystem carbon processes, especially when native plants are displaced by plants of a different functional group. Forb invasions into grasslands are common, yet little is known about how they impact carbon cycling. We conducted a field study over 2 years from April 2010 to March 2012 in China to examine changes in soil respiration (Rsoil) following invasion of exotic perennial forb species (Alternanthera philoxeroides or Solidago canadensis) into an annual grassland dominated by a native annual graminoid (Eragrostis pilosa). Measurements of Rsoil were taken once a week in stands of the native annual graminoid or one of the forb species using static chamber-gas chromatograph method. Aboveground litterfall of each of the three focal species was collected biweekly and litter decomposition rates were measured in a 6-month litterbag experiment. The monthly average and annual cumulative Rsoil increased following invasion by either forb species. The increases in cumulative Rsoil were smaller with invasion of Solidago (36%) than Alternanthera (65%). Both invasive forbs were associated with higher litter quantity and quality (e.g., C:N ratio) than the native annum graminoid. Compared to the native annual graminoid, the invasive forbs Altevnanthera (155%) and Solidago (361%) produced larger amounts of more rapidly decomposing litter, with the litter decay constant k being 3.8, 2.0 and 1.0 for Alternanthera, Solidago and Eragrostis, respectively. Functional groups of the invasive plants and the native plants they replaced appear to be useful predictors of directions of changes in Rsoil, but the magnitude of changes in Rsoil seems to be sensitive to variations in invader functional traits.