Camptotheac acuminata Decne is a unique tree species in China with an important secondary metabolite,camptothecin(CPT),used in the treatment of cancer.Nitrogen(N)is an important element that affects plant growth and t...Camptotheac acuminata Decne is a unique tree species in China with an important secondary metabolite,camptothecin(CPT),used in the treatment of cancer.Nitrogen(N)is an important element that affects plant growth and the accumulation of CPT.Reports on the effect of N on CPT synthesis from a genetic perspective are scarce.To explore the effects of different N sources and levels on CPT synthesis in C.acuminata,two-year-old seedlings were fertilized with different concentrations of pure ammonium sulphate,source of ammonium N(NH4+-N),and potassium nitrate for nitrate N(NO3--N).Concentrations of 2.5,5,7.5,and10 g pot-1 NH4+-N and NO3--N were used.The results showed that 7.5 g NH4+-N and NO3--N treatments were best for growth and fresh weight of leaves.Compared with the other treatments,the CPT content,tryptophan synthase and tryptophan decarboxylase activities,and expression of the CaTSB and CaTDCl genes under the 2.5 g NH4+-N and NO3--N treatments peaked significantly at 30 days.However,the expression of CaTDC2 surpassed that of the other two genes at 60 days.Therefore,compared with NH4+-N source,the NO3--N source was more beneficial for growth,and NO3--N was better for CPT yield.Consequently,leaves of C.acuminata treated with 2.5 g NO3--N could be harvested after 30 days to obtain maximum CPT content.CaTDC1 is more closely linked to CPT synthesis.The results of this study improved the production of CPT in C.acuminata via fertilization.展开更多
Globally,the prevalence of food allergy in children is estimated to be approximately 4%to 10%.[1]Food allergy usually begins early in the allergic march,and cow's milk allergy(CMA)is one of the most common food al...Globally,the prevalence of food allergy in children is estimated to be approximately 4%to 10%.[1]Food allergy usually begins early in the allergic march,and cow's milk allergy(CMA)is one of the most common food allergens in infants and children.In Europe,the overall incidence of challenge-proven CMA is 0.54%,and in the United States,the overall prevalence is 0.4%and pediatric prevalence is 1.9%.[2–4]In China,the prevalence of oral food challenge(OFC)-confirmed CMA is 0.83%to 3.5%in various cities.[5]Double-blind placebo-controlled food challenge is not applied widely in clinical practice because of its complex process and the risk of anaphylaxis for patients that receive the test.Allergen-specific IgE(sIgE)is usually used as a critical assessment method for food allergy.展开更多
基金This research was sponsored by the 13th Five-Year-Plan National Projects for Camptotheca acuminata Decne Effi cient Cultivation Technology Research of China(2017YFD0600706).
文摘Camptotheac acuminata Decne is a unique tree species in China with an important secondary metabolite,camptothecin(CPT),used in the treatment of cancer.Nitrogen(N)is an important element that affects plant growth and the accumulation of CPT.Reports on the effect of N on CPT synthesis from a genetic perspective are scarce.To explore the effects of different N sources and levels on CPT synthesis in C.acuminata,two-year-old seedlings were fertilized with different concentrations of pure ammonium sulphate,source of ammonium N(NH4+-N),and potassium nitrate for nitrate N(NO3--N).Concentrations of 2.5,5,7.5,and10 g pot-1 NH4+-N and NO3--N were used.The results showed that 7.5 g NH4+-N and NO3--N treatments were best for growth and fresh weight of leaves.Compared with the other treatments,the CPT content,tryptophan synthase and tryptophan decarboxylase activities,and expression of the CaTSB and CaTDCl genes under the 2.5 g NH4+-N and NO3--N treatments peaked significantly at 30 days.However,the expression of CaTDC2 surpassed that of the other two genes at 60 days.Therefore,compared with NH4+-N source,the NO3--N source was more beneficial for growth,and NO3--N was better for CPT yield.Consequently,leaves of C.acuminata treated with 2.5 g NO3--N could be harvested after 30 days to obtain maximum CPT content.CaTDC1 is more closely linked to CPT synthesis.The results of this study improved the production of CPT in C.acuminata via fertilization.
基金National Natural Science Foundation of China(No. 31972189)。
文摘Globally,the prevalence of food allergy in children is estimated to be approximately 4%to 10%.[1]Food allergy usually begins early in the allergic march,and cow's milk allergy(CMA)is one of the most common food allergens in infants and children.In Europe,the overall incidence of challenge-proven CMA is 0.54%,and in the United States,the overall prevalence is 0.4%and pediatric prevalence is 1.9%.[2–4]In China,the prevalence of oral food challenge(OFC)-confirmed CMA is 0.83%to 3.5%in various cities.[5]Double-blind placebo-controlled food challenge is not applied widely in clinical practice because of its complex process and the risk of anaphylaxis for patients that receive the test.Allergen-specific IgE(sIgE)is usually used as a critical assessment method for food allergy.
