Vegetation plays an important role in the environmental transport behavior of organic pollutants,however,the different roles of crops and natural vegetation have been ignored in most previous studies.In this study,we ...Vegetation plays an important role in the environmental transport behavior of organic pollutants,however,the different roles of crops and natural vegetation have been ignored in most previous studies.In this study,we developed the BETR-Urban-Rural-Veg model to quantitatively evaluate the influences of both natural vegetation and crops on the multimedia transport processes of Phenanthrene(PHE)and Benzo(a)pyrene(BaP)in mainland of China.The geographic distribution of polycyclic aromatic hydrocarbon(PAH)emissions and concentrations were consistent,displaying higher levels in northern China while lower levels in southern China.Under seasonal simulations,for both natural vegetation and crops,PAH concentrations in winter and spring were 1.5 to 27-fold higher than in summer and autumn,especially for PHE.Owing to the higher leaf area index(LAI)of natural vegetation and harvesting of crops,the filter and sequestration effect of natural vegetation was stronger than crops,while the seasonal changes of PAH concentrations in crops were more significant than natural vegetation.Temperature,precipitation rates and LAI might have important influences on seasonal concentrations and overall persistence of PAHs.PHE was more sensitive to the impacts of seasonal environmental parameters.Under different landscape scenarios,average annual PAH concentrations in natural vegetation were always a little higher than those in crops,and the overall persistence of BaP was greatly affected increasing by 15.15%-16.47%.This improved model provides a useful tool for environmental management.The results of this study are expected to support land use plans and decision-making in China's mainland.展开更多
Phthalic acid esters(PAEs)are a group of compounds widespread in the environment.To investigate the occurrence and accumulation characteristics of PAEs,surface water samples were collected from the Three Gorges Reserv...Phthalic acid esters(PAEs)are a group of compounds widespread in the environment.To investigate the occurrence and accumulation characteristics of PAEs,surface water samples were collected from the Three Gorges Reservoir area,China.The total concentrations of∑_(11)analyzed PAEs(11PAEs)in the collected water samples ranging from 197.7 to 1,409.3 ng/L(mean±IQR:583.1±308.4 ng/L).While DEHP was the most frequently detected PAE,DnBP and DnNP were the most predominant PAEs in the analyzed water samples with a mean contribution of 63.3%of the∑_(11)PAEs.The concentrations of the∑_(11)PAEs in the water samples from the upper reaches of the Yangtze River were significantly higher than those from themiddle reaches.To better understand the transport and fate of the PAEs,seven detected PAEs were modeled by Quantitative Water Air Sediment Interaction(QWASI).The simulated and measured values were close for most PAEs,and differences are within one order of magnitude even for the worst one.For all simulated PAEs,water and particle inflow were main sources in the reservoir,whereas water outflow and degradation in water were important removal pathways.The contribution ratios of different sources/losses varied fromPAEs,depending on their properties.The calculated risk quotients of DnNP in the Three Gorges Reservoir area whether based onmonitoring or simulating results were all far exceeded the safety threshold value,implying the occurrence of this PAE compound may cause potential adverse effects for the aquatic ecology of the Three Gorges Reservoir area.展开更多
Plant cells retain the ability for cellular reprogramming,including totipotency and pluripotency,enabling them to revert their cell fate from differentiated to dedifferentiated one and subsequently redifferentiate und...Plant cells retain the ability for cellular reprogramming,including totipotency and pluripotency,enabling them to revert their cell fate from differentiated to dedifferentiated one and subsequently redifferentiate under specific physiological and environmental cues.In response to these cues,endogenous phytohormones,genetic landscapes,and epigenetic remodeling play a significant role in initiating the reprogramming of somatic cells and re-establishment of an organized structure.Detailed studies on dedifferentiation have gradually unraveled the involvement of stem-like cells during early callus formation,along with the existence of QC-like transcriptional features in the middle cell layer of callus,which exhibits organ regeneration ability.Tracking natural variations and real-time regeneration dynamics across species,combined with single-cell RNA sequencing,will enable the identification of key developmental regulators and small peptides.These breakthroughs can be applied to enhance regeneration efficiency,improve transformation in recalcitrant species,and accelerate next-generation crop development.The current review summarizes the longstanding history and ongoing research progress in two pathways:dedifferentiation and redifferentiation.It also highlights how hormonal effects on the genetic factors and provides insights into how genetic signatures interact with epigenetic landscapes to drive these processes.It highlights the potential applications of developmental regulators for efficient gene transformation to enhance plant genetic engineering,while also addressing fundamental questions and identifying research gaps to guide future studies.展开更多
Objectives:Suicidal ideation is a strong predictor of suicide deaths,which refers to the consideration or desire to give up one's own life.Left-behind children in rural China are more vulnerable to psychological p...Objectives:Suicidal ideation is a strong predictor of suicide deaths,which refers to the consideration or desire to give up one's own life.Left-behind children in rural China are more vulnerable to psychological problems and suicidal ideation compared to their non-left-behind peers.The aim of the current study was to examine two potential protective factors,negotiable fate belief and coping self-efficacy,and to test the mediating role of coping self-efficacy in the relationship between negotiable fate belief and suicidal ideation.We also analyzed gender differences in this mediation model.Methods:Across-sectional survey was conducted in rural areas ofChina.A sample of 526 left-behind children(285 males,54.18%;241 females,45.82%;Meanage=13.29 years,SD=0.97 years)was recruited to complete the Negotiable Fate Belief Scale,Coping Self-Efficacy Scale,and the Positive and Negative Suicide Ideation Inventory-Negative Scale.We used structural equation modeling to test the mediation model and multigroup analysis to test the moderation effect of gender.Results:Negotiable fate belief is negatively correlated with suicidal ideation(r=-0.13,p<0.01).Moreover,coping self-efficacy mediates the relationship between negotiable fate belief and suicidal ideation(β=-0.06,95%confidence interval(CI)[-0.12,-0.02]),accounting for 35.29%of the total effect.Finally,the mediating effect of coping self-efficacy was found to be significant only for female left-behind children(male:95%CI[-0.09,0.07];female:95%CI[-0.16,-0.01]).For female left-behind children,the mediating effect was complete,with a coefficient of-0.06,accounting for 85.71%of the total effect.Conclusions:The relationship between negotiable fate belief and suicidal ideation among rural left-behind children is mediated by coping self-efficacy,and this mediation effect was moderated by gender.This study provides a theoretical explanation for how cultivating the belief in negotiable fate and coping self-efficacy is effective for reducing suicidal ideation of rural left-behind children.展开更多
The liver is a key endoderm-derived multifunctional organ within the digestive system.Prospero homeobox 1(Prox1)is an essential transcription factor for liver development,but its specific function is not well understo...The liver is a key endoderm-derived multifunctional organ within the digestive system.Prospero homeobox 1(Prox1)is an essential transcription factor for liver development,but its specific function is not well understood.Here,we show that hepatic development,including the formation of intrahepatic biliary and vascular networks,is severely disrupted in prox1a mutant zebrafish.We find that Prox1a is essential for liver growth and proper differentiation but not required for early hepatic cell fate specification.Intriguingly,prox1a depletion leads to ectopic initiation of a Cdx1b-mediated intestinal program and the formation of intestinal lumen-like structures within the liver.Morpholino knockdown of cdx1b alleviates liver defects in the prox1a mutant zebrafish.Finally,chromatin immunoprecipitation analysis reveals that Prox1a binds directly to the promoter region of cdx1b,thereby repressing its expression.Overall,our findings indicate that Prox1a is required to promote and protect hepatic development by repression of Cdx1b-mediated intestinal cell fate in zebrafish.展开更多
A recent study in the World Journal of Diabetes by Yang et al explored how Rheb1 signaling influenced pancreaticβcell fate and its potential as a therapeutic target.This invited commentary by a senior diabetes resear...A recent study in the World Journal of Diabetes by Yang et al explored how Rheb1 signaling influenced pancreaticβcell fate and its potential as a therapeutic target.This invited commentary by a senior diabetes researcher discussed the findings of Yang et al in the context of current knowledge onβcell biology,providing critical insight into the role of Rheb1 inβcell survival and function and the prospects for diabetes treatment.Key outcomes of the study were interpreted alongside established literature on Rheb1-mechanistic target of rapamycin signaling in islet cells.Rheb1 emerges as a pivotal regulator ofβcell growth and insulin secretory function,aligning with evidence thatβcell-specific Rheb1 deletion impairsβcell mass and glucose-stimulated insulin secretion.The commentary highlighted how modulating this pathway could preserve or restore theβcell population in diabetes while cautioning about potential off-target effects(e.g.inαcells).Targeting Rheb1 signaling represents a promising new frontier in diabetes therapy to enhanceβcell resilience;however,a balanced approach addressing both its benefits and risks is essential.This letter discussed the scientific implications and future research directions needed to translate Rheb1 modulation into clinical application for diabetes.展开更多
AIM:To explore the impact of insulin-like growth factor-1 receptorα(IGF-1Rα)on the differentiation fate of optic-cupderived retinal stem cells(OC-RSCs)into retinal ganglion cells(RGCs)in vitro.METHODS:OC-RSCs were i...AIM:To explore the impact of insulin-like growth factor-1 receptorα(IGF-1Rα)on the differentiation fate of optic-cupderived retinal stem cells(OC-RSCs)into retinal ganglion cells(RGCs)in vitro.METHODS:OC-RSCs were isolated from optic cups of rats on embryonic day 12.5,and high-purity OC-RSCs were obtained by conditioned culture and passage.Differentiation of OC-RSCs into RGCs under different serum concentrations was examined using flow cytometry,and the serum concentration with high interference with differentiation ratio was selected.Furthermore,the effect of blocking IGF-1Rαon the differentiation of OC-RSCs into RGCs was analyzed through immunocytochemistry and Western blotting.RESULTS:Immunohistochemical analysis revealed IGF-1Rαwas highly expressed in rat embryos at day 12.5.OC-RSCs were isolated and purified,and high-purity OCRSCs were obtained.When 2.5%serum was administered,the ratio of differentiated RGCs(Thy-1.1 positive)decreased significantly,and the results of immunoblotting also confirmed the blockade of IGF-1Rαreduced Thy-1.1 protein expression.CONCLUSION:IGF-1Rαblocking can reduce the differentiation of OC-RSCs into RGCs.展开更多
[Objective] The aim of this study was investigated the rice yield, nitrogen uptake and ^15-fertilizer fate at different transplanting density to provide scientific ba- sis for improving the yield of rice and applying ...[Objective] The aim of this study was investigated the rice yield, nitrogen uptake and ^15-fertilizer fate at different transplanting density to provide scientific ba- sis for improving the yield of rice and applying reasonably fertilizer. [Method] A field experiment was carried out to study the effect of different transplanting density on rice yield, nitrogen （N） absorption, sources of N uptake by rice and the N balance in the plant-soil systems by using ^15-labelled urea. [Result] There were no significant differences in rice yields and total N uptakes by rice between treatments 30 cm × 30 cm and 40 cm × 40 cm, but the yield of rice and total N absorption in the two treatments were remarkably higher than those in 50 cm × 50 cm treatment. The amounts of total N uptake by rice were in the range of 112.3-162.7 kg/hm2 in the three transplanting densities. The result showed that about 1/3 of the total N uptake by rice was supplied by application fertilizer and the other 2/3 was obtained from the soil N pool. The ^15N-labelled urea absorbed by rice, residual in soil and lost accounted for 16.3%-26.1%, 17.0%-20.9% and 53.0%-66.7% of the total fertilizer, respectively. A great deal of ^15N-labelled urea was lost during the rice growing season. [Conclusion] Considering the rice yield and environmental protection, the transplanting density of 30 cm×30 cm was recommended in the hilly area of Sichuan basin in the southwest China.展开更多
To understand the dynamics of added nitrogen (N) in alpine meadow and the role of alpine plants and soil microorganisms in the retention of deposited N, the fate of 15 N labeled nitrate and ammonium salts was...To understand the dynamics of added nitrogen (N) in alpine meadow and the role of alpine plants and soil microorganisms in the retention of deposited N, the fate of 15 N labeled nitrate and ammonium salts was determined in an alpine meadow for two months. Two weeks after 15 N application, total recovery of 15 N from NO - 3_ 15 N was 73.5% while it was 78% from NH + 4_ 15 N. More 15 N was recovered in plants than in soil organic matter or in microbial biomass, irrespective of forms of N added. After one month, 70.6% of added NO - 3_ 15 N and 57.4% of NH + 4_ 15 N were recovered in soils and plants. 15 N recovered in soil organic matter decreased greatly while that recovered in plants varied little, irrespective of the form N. Compared with the results of two weeks after 15 N application, more NO - 3_ 15 N than NH + 4_ 15 N was recovered in microbial biomass. Total recovery was 58.4% (six weeks) and 67% (eight weeks) from NO - 3_ 15 N, and 43.1% and 49% from NH + 4_ 15 N, respectively. Both plants and soil microorganism recovered more NO - 3_ 15 N than NH + 4_ 15 N. But plants recovered more 15 N than soil microorganisms. During the whole experiment plants retained more NO - 3_N and 15 N than soil microorganisms while 15 N recovered in inorganic N pool did not exceed 1% due to lower amount of inorganic N. This indicates that plants play more important roles in the retention of deposited N although microbial biomass can be an important sink for deposited N in early days after N application.展开更多
根据“预模式假说(Prepattern Hypothesis)”,黑腹果蝇(Drosophila melanogaster)背部感觉器官前体(sensory organ precursors,SOP)的发育依赖于预模式基因、原神经基因和神经源性基因的依次调控。大多数情况下,单一调控基因的功能失常...根据“预模式假说(Prepattern Hypothesis)”,黑腹果蝇(Drosophila melanogaster)背部感觉器官前体(sensory organ precursors,SOP)的发育依赖于预模式基因、原神经基因和神经源性基因的依次调控。大多数情况下,单一调控基因的功能失常引起的异位SOP形成,或表现为空间不连续,或仅限于原神经簇内。而fred基因的敲低会造成一种异位SOP发生的新型表型,这些异位SOP在空间上是连续的,且不局限于原神经簇区域。本研究发现,由敲减fred所诱导的异位SOP形成不依赖于原神经簇,表明几乎所有翅成虫盘细胞都具有潜在的神经发生潜力。并且,本研究还发现预模式基因pannier(pnr)与fred协同作用,以两种截然不同的方式调控SOP细胞的命运:一方面,pnr和fred在背板中部对于内源性SOP的形成是必需的;但另一方面,它们在原神经簇外协同抑制SOP发生。本研究结果打破了“预模式假说”中SOP形成依赖于原神经簇形成的论断,为该假说提供了一项重要补充。展开更多
Doris Lessing is a famous British female writer.Her short fiction to room 19 depicts the heroine Susan Rawing's tragic fate.The article makes an analysis on the feminine psychological need in the marriage from fou...Doris Lessing is a famous British female writer.Her short fiction to room 19 depicts the heroine Susan Rawing's tragic fate.The article makes an analysis on the feminine psychological need in the marriage from four aspects:Spiritual Freedom,Financially independent,interpersonal communication,mutual faith.展开更多
The Bluest Eye is Toni Morrison’s first novel.After its publication,it receives many criticisms.This article aims to ana lyze Pecola and Claudia’s understandings about black culture,then to clarify that different in...The Bluest Eye is Toni Morrison’s first novel.After its publication,it receives many criticisms.This article aims to ana lyze Pecola and Claudia’s understandings about black culture,then to clarify that different interpretations of the very name"the bluest eye"lead to different fates.With different visions of the black heritage,Pecola and Claudia have different perception of the world and thus have widely divergent outcomes in the painful circumstances.展开更多
基金supported by the National Natural Science Foundation of China(Nos.42107420,U23A20157,and U1910207)Shanxi Province Science Foundation for Young Scholars(No.20210302124363).
文摘Vegetation plays an important role in the environmental transport behavior of organic pollutants,however,the different roles of crops and natural vegetation have been ignored in most previous studies.In this study,we developed the BETR-Urban-Rural-Veg model to quantitatively evaluate the influences of both natural vegetation and crops on the multimedia transport processes of Phenanthrene(PHE)and Benzo(a)pyrene(BaP)in mainland of China.The geographic distribution of polycyclic aromatic hydrocarbon(PAH)emissions and concentrations were consistent,displaying higher levels in northern China while lower levels in southern China.Under seasonal simulations,for both natural vegetation and crops,PAH concentrations in winter and spring were 1.5 to 27-fold higher than in summer and autumn,especially for PHE.Owing to the higher leaf area index(LAI)of natural vegetation and harvesting of crops,the filter and sequestration effect of natural vegetation was stronger than crops,while the seasonal changes of PAH concentrations in crops were more significant than natural vegetation.Temperature,precipitation rates and LAI might have important influences on seasonal concentrations and overall persistence of PAHs.PHE was more sensitive to the impacts of seasonal environmental parameters.Under different landscape scenarios,average annual PAH concentrations in natural vegetation were always a little higher than those in crops,and the overall persistence of BaP was greatly affected increasing by 15.15%-16.47%.This improved model provides a useful tool for environmental management.The results of this study are expected to support land use plans and decision-making in China's mainland.
基金supported by the Innovation Fund of Nanjing Institute of Environmental Science,Ministry of Ecology and Environment,China(No.ZX2023QT003)the National Natural Science Foundation of China(No.22306130)+1 种基金Jiangsu Funding Program for Excellent Postdoctoral Talent(No.2022ZB789)the Ecological Environment Research Project of Jiangsu Province,China(No.2022014).
文摘Phthalic acid esters(PAEs)are a group of compounds widespread in the environment.To investigate the occurrence and accumulation characteristics of PAEs,surface water samples were collected from the Three Gorges Reservoir area,China.The total concentrations of∑_(11)analyzed PAEs(11PAEs)in the collected water samples ranging from 197.7 to 1,409.3 ng/L(mean±IQR:583.1±308.4 ng/L).While DEHP was the most frequently detected PAE,DnBP and DnNP were the most predominant PAEs in the analyzed water samples with a mean contribution of 63.3%of the∑_(11)PAEs.The concentrations of the∑_(11)PAEs in the water samples from the upper reaches of the Yangtze River were significantly higher than those from themiddle reaches.To better understand the transport and fate of the PAEs,seven detected PAEs were modeled by Quantitative Water Air Sediment Interaction(QWASI).The simulated and measured values were close for most PAEs,and differences are within one order of magnitude even for the worst one.For all simulated PAEs,water and particle inflow were main sources in the reservoir,whereas water outflow and degradation in water were important removal pathways.The contribution ratios of different sources/losses varied fromPAEs,depending on their properties.The calculated risk quotients of DnNP in the Three Gorges Reservoir area whether based onmonitoring or simulating results were all far exceeded the safety threshold value,implying the occurrence of this PAE compound may cause potential adverse effects for the aquatic ecology of the Three Gorges Reservoir area.
基金funded by National Key R&D Program of China(Grant No.2024YFD2200600)Science and Technology Project of Hebei Education Department(Grant No.QN2022017)+3 种基金Natural Science Foundation of Hebei Province(Grant No.C2023204062)Fundamental Scientific Research Fund of Universities in Hebei Province(KY2021059)China Agriculture Research System(Grant No.CARS-30-2-07)Hebei Agriculture Research System(Grant Nos.HBCT2024190201,HBCT2024190203).
文摘Plant cells retain the ability for cellular reprogramming,including totipotency and pluripotency,enabling them to revert their cell fate from differentiated to dedifferentiated one and subsequently redifferentiate under specific physiological and environmental cues.In response to these cues,endogenous phytohormones,genetic landscapes,and epigenetic remodeling play a significant role in initiating the reprogramming of somatic cells and re-establishment of an organized structure.Detailed studies on dedifferentiation have gradually unraveled the involvement of stem-like cells during early callus formation,along with the existence of QC-like transcriptional features in the middle cell layer of callus,which exhibits organ regeneration ability.Tracking natural variations and real-time regeneration dynamics across species,combined with single-cell RNA sequencing,will enable the identification of key developmental regulators and small peptides.These breakthroughs can be applied to enhance regeneration efficiency,improve transformation in recalcitrant species,and accelerate next-generation crop development.The current review summarizes the longstanding history and ongoing research progress in two pathways:dedifferentiation and redifferentiation.It also highlights how hormonal effects on the genetic factors and provides insights into how genetic signatures interact with epigenetic landscapes to drive these processes.It highlights the potential applications of developmental regulators for efficient gene transformation to enhance plant genetic engineering,while also addressing fundamental questions and identifying research gaps to guide future studies.
基金funded by the 2023Laibin City Philosophy and Social Science Research Project(No.2023LBZS035)2024Guangxi Student Innovation and Entrepreneurship Training Program Project(No.S202411546046X)2025 Research Project of Guangxi Science&Technology Normal University(No.GXKS2025YB020).
文摘Objectives:Suicidal ideation is a strong predictor of suicide deaths,which refers to the consideration or desire to give up one's own life.Left-behind children in rural China are more vulnerable to psychological problems and suicidal ideation compared to their non-left-behind peers.The aim of the current study was to examine two potential protective factors,negotiable fate belief and coping self-efficacy,and to test the mediating role of coping self-efficacy in the relationship between negotiable fate belief and suicidal ideation.We also analyzed gender differences in this mediation model.Methods:Across-sectional survey was conducted in rural areas ofChina.A sample of 526 left-behind children(285 males,54.18%;241 females,45.82%;Meanage=13.29 years,SD=0.97 years)was recruited to complete the Negotiable Fate Belief Scale,Coping Self-Efficacy Scale,and the Positive and Negative Suicide Ideation Inventory-Negative Scale.We used structural equation modeling to test the mediation model and multigroup analysis to test the moderation effect of gender.Results:Negotiable fate belief is negatively correlated with suicidal ideation(r=-0.13,p<0.01).Moreover,coping self-efficacy mediates the relationship between negotiable fate belief and suicidal ideation(β=-0.06,95%confidence interval(CI)[-0.12,-0.02]),accounting for 35.29%of the total effect.Finally,the mediating effect of coping self-efficacy was found to be significant only for female left-behind children(male:95%CI[-0.09,0.07];female:95%CI[-0.16,-0.01]).For female left-behind children,the mediating effect was complete,with a coefficient of-0.06,accounting for 85.71%of the total effect.Conclusions:The relationship between negotiable fate belief and suicidal ideation among rural left-behind children is mediated by coping self-efficacy,and this mediation effect was moderated by gender.This study provides a theoretical explanation for how cultivating the belief in negotiable fate and coping self-efficacy is effective for reducing suicidal ideation of rural left-behind children.
基金partially supported by grants from the National Key Research and Development Program of China and the National Natural Science Foundation of China(2018YFA0801000,32270889,2019YFA0802800,32070824,2015CB942800,2016YFA0100500,31871458,31671500,and 81371264)supported by Beijing Natural Science Foundation(5242009)a grant from the Fisheries Innovation Team of Beijing Agriculture Innovation Consortium(BAIC07-2023-02).
文摘The liver is a key endoderm-derived multifunctional organ within the digestive system.Prospero homeobox 1(Prox1)is an essential transcription factor for liver development,but its specific function is not well understood.Here,we show that hepatic development,including the formation of intrahepatic biliary and vascular networks,is severely disrupted in prox1a mutant zebrafish.We find that Prox1a is essential for liver growth and proper differentiation but not required for early hepatic cell fate specification.Intriguingly,prox1a depletion leads to ectopic initiation of a Cdx1b-mediated intestinal program and the formation of intestinal lumen-like structures within the liver.Morpholino knockdown of cdx1b alleviates liver defects in the prox1a mutant zebrafish.Finally,chromatin immunoprecipitation analysis reveals that Prox1a binds directly to the promoter region of cdx1b,thereby repressing its expression.Overall,our findings indicate that Prox1a is required to promote and protect hepatic development by repression of Cdx1b-mediated intestinal cell fate in zebrafish.
文摘A recent study in the World Journal of Diabetes by Yang et al explored how Rheb1 signaling influenced pancreaticβcell fate and its potential as a therapeutic target.This invited commentary by a senior diabetes researcher discussed the findings of Yang et al in the context of current knowledge onβcell biology,providing critical insight into the role of Rheb1 inβcell survival and function and the prospects for diabetes treatment.Key outcomes of the study were interpreted alongside established literature on Rheb1-mechanistic target of rapamycin signaling in islet cells.Rheb1 emerges as a pivotal regulator ofβcell growth and insulin secretory function,aligning with evidence thatβcell-specific Rheb1 deletion impairsβcell mass and glucose-stimulated insulin secretion.The commentary highlighted how modulating this pathway could preserve or restore theβcell population in diabetes while cautioning about potential off-target effects(e.g.inαcells).Targeting Rheb1 signaling represents a promising new frontier in diabetes therapy to enhanceβcell resilience;however,a balanced approach addressing both its benefits and risks is essential.This letter discussed the scientific implications and future research directions needed to translate Rheb1 modulation into clinical application for diabetes.
文摘AIM:To explore the impact of insulin-like growth factor-1 receptorα(IGF-1Rα)on the differentiation fate of optic-cupderived retinal stem cells(OC-RSCs)into retinal ganglion cells(RGCs)in vitro.METHODS:OC-RSCs were isolated from optic cups of rats on embryonic day 12.5,and high-purity OC-RSCs were obtained by conditioned culture and passage.Differentiation of OC-RSCs into RGCs under different serum concentrations was examined using flow cytometry,and the serum concentration with high interference with differentiation ratio was selected.Furthermore,the effect of blocking IGF-1Rαon the differentiation of OC-RSCs into RGCs was analyzed through immunocytochemistry and Western blotting.RESULTS:Immunohistochemical analysis revealed IGF-1Rαwas highly expressed in rat embryos at day 12.5.OC-RSCs were isolated and purified,and high-purity OCRSCs were obtained.When 2.5%serum was administered,the ratio of differentiated RGCs(Thy-1.1 positive)decreased significantly,and the results of immunoblotting also confirmed the blockade of IGF-1Rαreduced Thy-1.1 protein expression.CONCLUSION:IGF-1Rαblocking can reduce the differentiation of OC-RSCs into RGCs.
基金Supported by the Financial Breeding Fund for Young Scholars in Sichuan Province(2008QNJJ-016)Financial Fund for Excellent Gene Engineering Papers in Sichuan Province (2010LWJJ-008)~~
文摘[Objective] The aim of this study was investigated the rice yield, nitrogen uptake and ^15-fertilizer fate at different transplanting density to provide scientific ba- sis for improving the yield of rice and applying reasonably fertilizer. [Method] A field experiment was carried out to study the effect of different transplanting density on rice yield, nitrogen （N） absorption, sources of N uptake by rice and the N balance in the plant-soil systems by using ^15-labelled urea. [Result] There were no significant differences in rice yields and total N uptakes by rice between treatments 30 cm × 30 cm and 40 cm × 40 cm, but the yield of rice and total N absorption in the two treatments were remarkably higher than those in 50 cm × 50 cm treatment. The amounts of total N uptake by rice were in the range of 112.3-162.7 kg/hm2 in the three transplanting densities. The result showed that about 1/3 of the total N uptake by rice was supplied by application fertilizer and the other 2/3 was obtained from the soil N pool. The ^15N-labelled urea absorbed by rice, residual in soil and lost accounted for 16.3%-26.1%, 17.0%-20.9% and 53.0%-66.7% of the total fertilizer, respectively. A great deal of ^15N-labelled urea was lost during the rice growing season. [Conclusion] Considering the rice yield and environmental protection, the transplanting density of 30 cm×30 cm was recommended in the hilly area of Sichuan basin in the southwest China.
文摘To understand the dynamics of added nitrogen (N) in alpine meadow and the role of alpine plants and soil microorganisms in the retention of deposited N, the fate of 15 N labeled nitrate and ammonium salts was determined in an alpine meadow for two months. Two weeks after 15 N application, total recovery of 15 N from NO - 3_ 15 N was 73.5% while it was 78% from NH + 4_ 15 N. More 15 N was recovered in plants than in soil organic matter or in microbial biomass, irrespective of forms of N added. After one month, 70.6% of added NO - 3_ 15 N and 57.4% of NH + 4_ 15 N were recovered in soils and plants. 15 N recovered in soil organic matter decreased greatly while that recovered in plants varied little, irrespective of the form N. Compared with the results of two weeks after 15 N application, more NO - 3_ 15 N than NH + 4_ 15 N was recovered in microbial biomass. Total recovery was 58.4% (six weeks) and 67% (eight weeks) from NO - 3_ 15 N, and 43.1% and 49% from NH + 4_ 15 N, respectively. Both plants and soil microorganism recovered more NO - 3_ 15 N than NH + 4_ 15 N. But plants recovered more 15 N than soil microorganisms. During the whole experiment plants retained more NO - 3_N and 15 N than soil microorganisms while 15 N recovered in inorganic N pool did not exceed 1% due to lower amount of inorganic N. This indicates that plants play more important roles in the retention of deposited N although microbial biomass can be an important sink for deposited N in early days after N application.
文摘根据“预模式假说(Prepattern Hypothesis)”,黑腹果蝇(Drosophila melanogaster)背部感觉器官前体(sensory organ precursors,SOP)的发育依赖于预模式基因、原神经基因和神经源性基因的依次调控。大多数情况下,单一调控基因的功能失常引起的异位SOP形成,或表现为空间不连续,或仅限于原神经簇内。而fred基因的敲低会造成一种异位SOP发生的新型表型,这些异位SOP在空间上是连续的,且不局限于原神经簇区域。本研究发现,由敲减fred所诱导的异位SOP形成不依赖于原神经簇,表明几乎所有翅成虫盘细胞都具有潜在的神经发生潜力。并且,本研究还发现预模式基因pannier(pnr)与fred协同作用,以两种截然不同的方式调控SOP细胞的命运:一方面,pnr和fred在背板中部对于内源性SOP的形成是必需的;但另一方面,它们在原神经簇外协同抑制SOP发生。本研究结果打破了“预模式假说”中SOP形成依赖于原神经簇形成的论断,为该假说提供了一项重要补充。
文摘Doris Lessing is a famous British female writer.Her short fiction to room 19 depicts the heroine Susan Rawing's tragic fate.The article makes an analysis on the feminine psychological need in the marriage from four aspects:Spiritual Freedom,Financially independent,interpersonal communication,mutual faith.
文摘The Bluest Eye is Toni Morrison’s first novel.After its publication,it receives many criticisms.This article aims to ana lyze Pecola and Claudia’s understandings about black culture,then to clarify that different interpretations of the very name"the bluest eye"lead to different fates.With different visions of the black heritage,Pecola and Claudia have different perception of the world and thus have widely divergent outcomes in the painful circumstances.
