This paper reports the preparation of three di‑iron complexes containing a thiazole moiety.Esterification of complex[Fe_(2)(CO)_(6)(μ‑SCH_(2)CH(CH_(2)OH)S)](1)with 4‑methylthiazole‑5‑carboxylic acid gave the correspo...This paper reports the preparation of three di‑iron complexes containing a thiazole moiety.Esterification of complex[Fe_(2)(CO)_(6)(μ‑SCH_(2)CH(CH_(2)OH)S)](1)with 4‑methylthiazole‑5‑carboxylic acid gave the corresponding ester[Fe_(2)(CO)_(6)(μ‑tedt)](2),where tedt=SCH_(2)CH(CH_(2)OOC(5‑C_(3)HNSCH_(3)))S.Further reactions of complex 2 with tri(ptolyl)phosphine(tp)or tris(4‑fluorophenyl)phosphine(fp)gave the phosphine‑substituted derivatives[Fe_(2)(CO)_(5)(tp)(μ‑tedt)](3)and[Fe_(2)(CO)_(5)(fp)(μ‑tedt)](4).The structures of the newly prepared complexes were elucidated by elemental analysis,NMR,IR,and X‑ray photoelectron spectroscopy.Moreover,single‑crystal X‑ray diffraction analysis confirmed their molecular structures,showing that they contain a di‑iron core ligated by a bridged dithiolate bearing a thiazole moiety and terminal carbonyls.The electrochemical and electrocatalytic proton reduction were probed by cyclic voltammetry,revealing that three complexes can catalyze the reduction of protons to H_(2) under the electrochemical conditions.For comparison,complex 4 possessed the best efficiency with a turnover frequency of 23.5 s^(-1)at 10 mmol·L^(-1)HOAc concentration.In addition,the fungicidal activity of these complexes was also investigated in this study.CCDC:2477511,2;2477512,3;2477513,4.展开更多
Camptotheca acuminata Decaisne is a tree unique to China, producing terpenoid indole alkaloid (TIA), camptothecin (CPT), and 10-hydroxycamptothecin (HCPT), which possesses strong anti-cancer bioactivity. The dynamics ...Camptotheca acuminata Decaisne is a tree unique to China, producing terpenoid indole alkaloid (TIA), camptothecin (CPT), and 10-hydroxycamptothecin (HCPT), which possesses strong anti-cancer bioactivity. The dynamics of HCPT and CPT during seed maturation, seed germination, postgerminative development and daily growth were measured by High Performance Liquid Chromatography (HPLC). This article provides some evidence for presenting the theory that each characteristic of HCPT and CPT accumulation is under developmental regulation and then attempt to elucidate the metabolic relationships between them. HCPT accumulates particularly in young tissues and organs and is relatively unstable, while the distribution of CPT is more ubiquitous and stable. Their different distribution properties suggest that HCPT and CPT are differentially regulated and play distinct roles:during development.展开更多
Plants interact with their environment by producing a diverse array of secondary metabolites, one of which is alkaloid. In this study, alkaloids, including camptothecin (CPT) and 10-hydroxycamptothecin (HCPT), malondi...Plants interact with their environment by producing a diverse array of secondary metabolites, one of which is alkaloid. In this study, alkaloids, including camptothecin (CPT) and 10-hydroxycamptothecin (HCPT), malondialdehyde (MDA) and chlorophyll contents were measured during heat shock in seedlings of Camptotheca acuminata Decaisne unique to China. Responses of different tissues, including young leaves, old leaves, buds and barks, to heat shock were examined in alkaloid changes. CPT and HCPT concentrations reached their peak values separately at 38 degreesC and 40 degreesC, which were below the lethal heat-shock temperature indicated by MDA and chlorophyll, and their great changes took place in young leaves. These results indicated that CPT and HCPT were involved in the C acuminata resistance against heat shock from its environment. Furthermore, plant rigidly observed the cost-benefit principle and mobilized and allocated limited alkaloid sources to young and reproductive tissues preferentially. In addition, HCPT displayed well-regulated changes during incubation at sublethal temperature, and this indicated that HCPT might play a more positively defensive role in enhancement of plant thermotolerance than CPT does.展开更多
Nitrate reductase activity (NRA) in different plant organs and leaves in different positions of Camptotheca acuminata seedlings was determined by an In vivo assay, the diurnal variation rhythm of NRA in leaves of diff...Nitrate reductase activity (NRA) in different plant organs and leaves in different positions of Camptotheca acuminata seedlings was determined by an In vivo assay, the diurnal variation rhythm of NRA in leaves of different positions was observed,and the correlations between leaf NRA, leaf area and lamina mass per unit area (LMA) were also examined. The results showed that NRA in the leaf was significantly highest, compared with that in other organs such as roots, stems and leaves. In this experiment, the 10 leaves were selected from the apex to the base of the seedlings in order. The different NRA occurred obviously in leaves of different positions of C. acuminata seedlings from the apex to the base, and NRA was higher in the 4th-6th leaves.The diurnal change rhythm of leaf NRA showed a one peak curve, and maximum NRA value appeared at about midday (at 12:30 or so). No obvious correlations between NRA and leaf area or lamina mass per unit area were observed. This study offered scientific foundation for the further research on nitrogen metabolism of C. acuminata.展开更多
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
Diabetes is an urgent health issue characterized by ethnic and regional variations,and is inseparable from the differ-ent dietary habits.It is worthy to note that the incidence of diabetes in Bai nationality has been ...Diabetes is an urgent health issue characterized by ethnic and regional variations,and is inseparable from the differ-ent dietary habits.It is worthy to note that the incidence of diabetes in Bai nationality has been reported to be much lower than Han in China.As a daily vegetable of Bai,the phytochemical and antidiabetic study of Ottelia acuminata var.acuminata had not been carried out.In this study,41 metabolites with diverse diarylheptanoid(six new ones,Otteacumienes A-F),flavone,sesquiterpenoid,coumarin,lignan,polyacetylene,and alkaloid skeletons were charac-terized from O.acuminata var.acuminata.Among them,the racemic nature of 3 was characterized by chiral resolution and calculated ECD methods.The biological study revealed diarylheptanoids showed significantα-glucosidase inhibi-tory activities with 5 as the most effective one(60-fold stronger than acarbose).Molecular docking studies indicated that these structures have different binding cavities with acarbose.This study demonstrated that O.acuminata var.acuminata might correlated with the low incidence diabetes of Bai and the diarylheptanoids may have potential therapeutic value for diabetes mellitus.展开更多
The dinoflagellate Dinophysis acurninata Claparede ＆ Lachrnann is a toxic alga that causes diarrhetic shellfish poisoning. No Dinophysis species were maintained in culture for a long period of time until 2006 when Pa...The dinoflagellate Dinophysis acurninata Claparede ＆ Lachrnann is a toxic alga that causes diarrhetic shellfish poisoning. No Dinophysis species were maintained in culture for a long period of time until 2006 when Park successfully established D. acuminata in culture using a three-step feeding protocol in which the cryptophyte, Geminigera cryophila, is fed to Myrionecta rubra （=Mesodinium rubrum）, a ciliate that is in turn fed to D. acuminata. In this paper, we present the details of culturing D. acuminata from the Northeastern United States. The protocols described herein can be adopted for laboratory studies of this species. The effects of temperature on the growth and ingestion rates of D. acuminata were also examined. The results show that D. acuminata growth rate was 0.23/d at 10℃ and 0.11/d at 4℃when fed M. rubra prey. The maximum prey ingestion rate was 2.80 Dinophysis cell/d at 10℃, although the rate decreased slightly at 4℃. In overall, temperature showed a greater influence on growth rate of D. acuminata than on the ingestion rate under the study conditions, and the quantity of available food was also an important regulator to D. acurninata growth.展开更多
This study differentiated pseudocondyloma of vulva from condyloma acuminata using dot blot hybridization and polymerase chain reaction (PCR). A total of 27 cases of pseudocondyloma of vulva and 65 cases of condyloma a...This study differentiated pseudocondyloma of vulva from condyloma acuminata using dot blot hybridization and polymerase chain reaction (PCR). A total of 27 cases of pseudocondyloma of vulva and 65 cases of condyloma acuminata were selected for the study. The genital lesions were examined clinically and were biopsied. Each biopsy was subjected to histological examination and HPV DNA analysis by dot blot hybridization and PCR. Dot blot analysis detected HPV DNA in 19(82. 6%) out of 23 cases of condyloma acuminata and 2(25% ) out of 8 cases pseudocondyloma of vulvae (P<0. 05). PCR detected HPV DNA in 51 (92. 7%) out of 55 cases of condyloma acuminata , compared with none in 23 cases of pseudocondyloma (P<0.001 ). HPV DNA was present in the majority of condyloma acuminata specimens. HPV 6 and 11 were the predominant types. Peudocondyloma is probably not associated with HPV. PCR was the most sensitive and useful technique for HPV DNA detection.展开更多
The effects of initial sucrose concentration, nitrate to ammonium ratio, total N concentration and phosphate concentration in medium on cell growth and isocamptothecin A and B synthesis by suspension call culture of C...The effects of initial sucrose concentration, nitrate to ammonium ratio, total N concentration and phosphate concentration in medium on cell growth and isocamptothecin A and B synthesis by suspension call culture of Camptotheca acuminata were investigated in 250 mL shake flasks. 30 g L^-1 sucrose concentration was beneficial to secondary metabolites synthesis. The cell growth and metabolites synthesis were also affected by the ratio of NO3^-/NH4^＋ , and nitrate was tavourable for cell growth. The maximum dry weight was achieved when nitrate was used as the sole N souree. The effect of total initial N on the cell cultures was also investigated with NO3^-/NH4^＋ ratio of 1 ： 2. The final dry cell weight was similar throughout culture period and 50 mM initial N was favourable for secondary metabolite synthesis. 50 mM initial phosphate concentration facilitated both cell growth and secondary metabolites synthesis.展开更多
UGPase gene related with wood cellulose synthesis was transferred into C. acuminata using the method of Agrobacte- rium-mediated genetic transformation, and an efficient transformation system was developed for C. acum...UGPase gene related with wood cellulose synthesis was transferred into C. acuminata using the method of Agrobacte- rium-mediated genetic transformation, and an efficient transformation system was developed for C. acuminata on the basis of evaluations of several factors affecting Agrobacterium-mediated DNA transfer rate. The highest transformation rate was achieved when pre-cultttred leaf explants were infected with an Agrobacterium culture corresponding to OD600 （0.5） for 10 min, and cultured on explant regeneration medium for three days. The results of Southern hybridization showed that genomic DNA of the kanamycin-resistant shoots to an UGPase gene probe substantiated the integration of the transgene. Transformation efficiency （6%） was achieved under the optimized transformation procedure, This system should facilitate the introduction of important useful genes into C, acuminata.展开更多
In this study,we investigated the effects of different concentrations of 5-azacytidine(AZA),a DNA methyltransferase in-hibitor,on the growth,antioxidant activities and germination of pellicle cysts of Scrippsiella acu...In this study,we investigated the effects of different concentrations of 5-azacytidine(AZA),a DNA methyltransferase in-hibitor,on the growth,antioxidant activities and germination of pellicle cysts of Scrippsiella acuminata.The purpose of this study is to understand the toxic effects of AZA on marine microalgae,and to demonstrate the effect of DNA methyltransferase inhibitors on the germination of pellicle cysts.Results showed that AZA inhibited the growth of S.acuminata significantly,and displaced a clear dose-dependent inhibition trend with the 96h EC50 of 146.77μmolL^(-1)(35.84mgL^(-1)).Pellicle cysts of S.acuminata were less sensitive to AZA than the vegetative cells,and the EC50 value of AZA to the germination of pellicle cysts of S.acuminata was 8.08mmolL^(-1)(1.97g L^(-1)).After exposed to AZA,the antioxidant activities in S.acuminata responded rapidly and significantly.Among them,soluble pro-tein and superoxide dismutase(SOD)were more sensitive to AZA,and significant promotions occurred after exposed to 10μmolL^(-1)AZA for 24h.Meanwhile,malondialdehyde(MDA)contents in algal cells did not change significantly after exposed to low concen-trations of AZA,but increased firstly and then decreased under high concentration of AZA.The glutathione(GSH)levels in S.acu-minata increased significantly under high concentrations of AZA,and remained unchanged at low concentrations of AZA.The results suggested that the enhanced protein level and SOD activity of S.acuminata eliminated reactive oxygen species(ROS)to a certain ex-tent,and thus protected algal cells against damages of ROS caused by AZA.展开更多
Drought stress has become more common in recent years as a result of climate change impacts on the production of banana crops and other fruit trees.The growth and productivity of Musa spp are severely impacted by the ...Drought stress has become more common in recent years as a result of climate change impacts on the production of banana crops and other fruit trees.The growth and productivity of Musa spp are severely impacted by the gradual degradation of water resources and the erratic distribution pattern of annual precipitation amount.The aim of the work includes increased drought tolerance in light of water scarcity in the world as a result of the bananas’being gluttonous for water needs.This investigation was carried out from 2019 to 2020 to study the effect of potassium silicate on morphological growth and biochemical parameters of Musa acuminata L under drought stress by PEG.As a result,drought stress reduced the morphological characteristics such as shoots number,shoot length,roots number,and survival percentage and biochemical characteristics such as chlorophyll a,b,carotenoids,stomatal status,and RWC.While proline content increased in the leaf of M.acuminata L.Media complemented with K2SiO3(2 to 6 mM)either individually or in combination with PEG led to an improvement in all morphological and biochemical characteristics.The activities of CAT,POD,and PPO enzymes increased significantly compared to control.Furthermore,the lowest PPO,CAT,and POD activity were achieved.Additionally,K2SiO3 treatments under drought stress successfully enhanced the leaf stomatal behavior.Our results suggest that K2SiO3 can help to maintain plant integrity in the tested cultivar under drought stress.展开更多
文摘This paper reports the preparation of three di‑iron complexes containing a thiazole moiety.Esterification of complex[Fe_(2)(CO)_(6)(μ‑SCH_(2)CH(CH_(2)OH)S)](1)with 4‑methylthiazole‑5‑carboxylic acid gave the corresponding ester[Fe_(2)(CO)_(6)(μ‑tedt)](2),where tedt=SCH_(2)CH(CH_(2)OOC(5‑C_(3)HNSCH_(3)))S.Further reactions of complex 2 with tri(ptolyl)phosphine(tp)or tris(4‑fluorophenyl)phosphine(fp)gave the phosphine‑substituted derivatives[Fe_(2)(CO)_(5)(tp)(μ‑tedt)](3)and[Fe_(2)(CO)_(5)(fp)(μ‑tedt)](4).The structures of the newly prepared complexes were elucidated by elemental analysis,NMR,IR,and X‑ray photoelectron spectroscopy.Moreover,single‑crystal X‑ray diffraction analysis confirmed their molecular structures,showing that they contain a di‑iron core ligated by a bridged dithiolate bearing a thiazole moiety and terminal carbonyls.The electrochemical and electrocatalytic proton reduction were probed by cyclic voltammetry,revealing that three complexes can catalyze the reduction of protons to H_(2) under the electrochemical conditions.For comparison,complex 4 possessed the best efficiency with a turnover frequency of 23.5 s^(-1)at 10 mmol·L^(-1)HOAc concentration.In addition,the fungicidal activity of these complexes was also investigated in this study.CCDC:2477511,2;2477512,3;2477513,4.
文摘Camptotheca acuminata Decaisne is a tree unique to China, producing terpenoid indole alkaloid (TIA), camptothecin (CPT), and 10-hydroxycamptothecin (HCPT), which possesses strong anti-cancer bioactivity. The dynamics of HCPT and CPT during seed maturation, seed germination, postgerminative development and daily growth were measured by High Performance Liquid Chromatography (HPLC). This article provides some evidence for presenting the theory that each characteristic of HCPT and CPT accumulation is under developmental regulation and then attempt to elucidate the metabolic relationships between them. HCPT accumulates particularly in young tissues and organs and is relatively unstable, while the distribution of CPT is more ubiquitous and stable. Their different distribution properties suggest that HCPT and CPT are differentially regulated and play distinct roles:during development.
文摘Plants interact with their environment by producing a diverse array of secondary metabolites, one of which is alkaloid. In this study, alkaloids, including camptothecin (CPT) and 10-hydroxycamptothecin (HCPT), malondialdehyde (MDA) and chlorophyll contents were measured during heat shock in seedlings of Camptotheca acuminata Decaisne unique to China. Responses of different tissues, including young leaves, old leaves, buds and barks, to heat shock were examined in alkaloid changes. CPT and HCPT concentrations reached their peak values separately at 38 degreesC and 40 degreesC, which were below the lethal heat-shock temperature indicated by MDA and chlorophyll, and their great changes took place in young leaves. These results indicated that CPT and HCPT were involved in the C acuminata resistance against heat shock from its environment. Furthermore, plant rigidly observed the cost-benefit principle and mobilized and allocated limited alkaloid sources to young and reproductive tissues preferentially. In addition, HCPT displayed well-regulated changes during incubation at sublethal temperature, and this indicated that HCPT might play a more positively defensive role in enhancement of plant thermotolerance than CPT does.
文摘Nitrate reductase activity (NRA) in different plant organs and leaves in different positions of Camptotheca acuminata seedlings was determined by an In vivo assay, the diurnal variation rhythm of NRA in leaves of different positions was observed,and the correlations between leaf NRA, leaf area and lamina mass per unit area (LMA) were also examined. The results showed that NRA in the leaf was significantly highest, compared with that in other organs such as roots, stems and leaves. In this experiment, the 10 leaves were selected from the apex to the base of the seedlings in order. The different NRA occurred obviously in leaves of different positions of C. acuminata seedlings from the apex to the base, and NRA was higher in the 4th-6th leaves.The diurnal change rhythm of leaf NRA showed a one peak curve, and maximum NRA value appeared at about midday (at 12:30 or so). No obvious correlations between NRA and leaf area or lamina mass per unit area were observed. This study offered scientific foundation for the further research on nitrogen metabolism of C. acuminata.
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supported financially by the Second Tibetan Plateau Scientific Expedition and Research program (2019QZKK0502)State Key Laboratory of Phytochemistry and Plant Resources in West China (E0230211Z1 and P2019-ZZ05).
文摘Diabetes is an urgent health issue characterized by ethnic and regional variations,and is inseparable from the differ-ent dietary habits.It is worthy to note that the incidence of diabetes in Bai nationality has been reported to be much lower than Han in China.As a daily vegetable of Bai,the phytochemical and antidiabetic study of Ottelia acuminata var.acuminata had not been carried out.In this study,41 metabolites with diverse diarylheptanoid(six new ones,Otteacumienes A-F),flavone,sesquiterpenoid,coumarin,lignan,polyacetylene,and alkaloid skeletons were charac-terized from O.acuminata var.acuminata.Among them,the racemic nature of 3 was characterized by chiral resolution and calculated ECD methods.The biological study revealed diarylheptanoids showed significantα-glucosidase inhibi-tory activities with 5 as the most effective one(60-fold stronger than acarbose).Molecular docking studies indicated that these structures have different binding cavities with acarbose.This study demonstrated that O.acuminata var.acuminata might correlated with the low incidence diabetes of Bai and the diarylheptanoids may have potential therapeutic value for diabetes mellitus.
基金provided by a grand fostering project from the Ministry of Education,People’s Republic of China (No 707011)the China Scholarship Council(CSC)2007+2 种基金supported by grants (to ANDERSON M Donald) from the US. National Science Foundation (Nos. NSF OCE-0402707OCE-0850421)the Ocean Life Institute at the Woods Hole Oceanographic Institution
文摘The dinoflagellate Dinophysis acurninata Claparede ＆ Lachrnann is a toxic alga that causes diarrhetic shellfish poisoning. No Dinophysis species were maintained in culture for a long period of time until 2006 when Park successfully established D. acuminata in culture using a three-step feeding protocol in which the cryptophyte, Geminigera cryophila, is fed to Myrionecta rubra （=Mesodinium rubrum）, a ciliate that is in turn fed to D. acuminata. In this paper, we present the details of culturing D. acuminata from the Northeastern United States. The protocols described herein can be adopted for laboratory studies of this species. The effects of temperature on the growth and ingestion rates of D. acuminata were also examined. The results show that D. acuminata growth rate was 0.23/d at 10℃ and 0.11/d at 4℃when fed M. rubra prey. The maximum prey ingestion rate was 2.80 Dinophysis cell/d at 10℃, although the rate decreased slightly at 4℃. In overall, temperature showed a greater influence on growth rate of D. acuminata than on the ingestion rate under the study conditions, and the quantity of available food was also an important regulator to D. acurninata growth.
文摘This study differentiated pseudocondyloma of vulva from condyloma acuminata using dot blot hybridization and polymerase chain reaction (PCR). A total of 27 cases of pseudocondyloma of vulva and 65 cases of condyloma acuminata were selected for the study. The genital lesions were examined clinically and were biopsied. Each biopsy was subjected to histological examination and HPV DNA analysis by dot blot hybridization and PCR. Dot blot analysis detected HPV DNA in 19(82. 6%) out of 23 cases of condyloma acuminata and 2(25% ) out of 8 cases pseudocondyloma of vulvae (P<0. 05). PCR detected HPV DNA in 51 (92. 7%) out of 55 cases of condyloma acuminata , compared with none in 23 cases of pseudocondyloma (P<0.001 ). HPV DNA was present in the majority of condyloma acuminata specimens. HPV 6 and 11 were the predominant types. Peudocondyloma is probably not associated with HPV. PCR was the most sensitive and useful technique for HPV DNA detection.
基金Supported by the National Natural Science Foundation of China （No. 20176058）.
文摘The effects of initial sucrose concentration, nitrate to ammonium ratio, total N concentration and phosphate concentration in medium on cell growth and isocamptothecin A and B synthesis by suspension call culture of Camptotheca acuminata were investigated in 250 mL shake flasks. 30 g L^-1 sucrose concentration was beneficial to secondary metabolites synthesis. The cell growth and metabolites synthesis were also affected by the ratio of NO3^-/NH4^＋ , and nitrate was tavourable for cell growth. The maximum dry weight was achieved when nitrate was used as the sole N souree. The effect of total initial N on the cell cultures was also investigated with NO3^-/NH4^＋ ratio of 1 ： 2. The final dry cell weight was similar throughout culture period and 50 mM initial N was favourable for secondary metabolite synthesis. 50 mM initial phosphate concentration facilitated both cell growth and secondary metabolites synthesis.
文摘UGPase gene related with wood cellulose synthesis was transferred into C. acuminata using the method of Agrobacte- rium-mediated genetic transformation, and an efficient transformation system was developed for C. acuminata on the basis of evaluations of several factors affecting Agrobacterium-mediated DNA transfer rate. The highest transformation rate was achieved when pre-cultttred leaf explants were infected with an Agrobacterium culture corresponding to OD600 （0.5） for 10 min, and cultured on explant regeneration medium for three days. The results of Southern hybridization showed that genomic DNA of the kanamycin-resistant shoots to an UGPase gene probe substantiated the integration of the transgene. Transformation efficiency （6%） was achieved under the optimized transformation procedure, This system should facilitate the introduction of important useful genes into C, acuminata.
基金supported by the National Natural Science Foundation of China(No.42076141).
文摘In this study,we investigated the effects of different concentrations of 5-azacytidine(AZA),a DNA methyltransferase in-hibitor,on the growth,antioxidant activities and germination of pellicle cysts of Scrippsiella acuminata.The purpose of this study is to understand the toxic effects of AZA on marine microalgae,and to demonstrate the effect of DNA methyltransferase inhibitors on the germination of pellicle cysts.Results showed that AZA inhibited the growth of S.acuminata significantly,and displaced a clear dose-dependent inhibition trend with the 96h EC50 of 146.77μmolL^(-1)(35.84mgL^(-1)).Pellicle cysts of S.acuminata were less sensitive to AZA than the vegetative cells,and the EC50 value of AZA to the germination of pellicle cysts of S.acuminata was 8.08mmolL^(-1)(1.97g L^(-1)).After exposed to AZA,the antioxidant activities in S.acuminata responded rapidly and significantly.Among them,soluble pro-tein and superoxide dismutase(SOD)were more sensitive to AZA,and significant promotions occurred after exposed to 10μmolL^(-1)AZA for 24h.Meanwhile,malondialdehyde(MDA)contents in algal cells did not change significantly after exposed to low concen-trations of AZA,but increased firstly and then decreased under high concentration of AZA.The glutathione(GSH)levels in S.acu-minata increased significantly under high concentrations of AZA,and remained unchanged at low concentrations of AZA.The results suggested that the enhanced protein level and SOD activity of S.acuminata eliminated reactive oxygen species(ROS)to a certain ex-tent,and thus protected algal cells against damages of ROS caused by AZA.
基金funded by Princess Nourah bint Abdulrahman University Researchers Supporting Project No.(PNURSP2022R188)Princess Nourah bint Abdulrahman University,Riyadh,Saudi Arabia。
文摘Drought stress has become more common in recent years as a result of climate change impacts on the production of banana crops and other fruit trees.The growth and productivity of Musa spp are severely impacted by the gradual degradation of water resources and the erratic distribution pattern of annual precipitation amount.The aim of the work includes increased drought tolerance in light of water scarcity in the world as a result of the bananas’being gluttonous for water needs.This investigation was carried out from 2019 to 2020 to study the effect of potassium silicate on morphological growth and biochemical parameters of Musa acuminata L under drought stress by PEG.As a result,drought stress reduced the morphological characteristics such as shoots number,shoot length,roots number,and survival percentage and biochemical characteristics such as chlorophyll a,b,carotenoids,stomatal status,and RWC.While proline content increased in the leaf of M.acuminata L.Media complemented with K2SiO3(2 to 6 mM)either individually or in combination with PEG led to an improvement in all morphological and biochemical characteristics.The activities of CAT,POD,and PPO enzymes increased significantly compared to control.Furthermore,the lowest PPO,CAT,and POD activity were achieved.Additionally,K2SiO3 treatments under drought stress successfully enhanced the leaf stomatal behavior.Our results suggest that K2SiO3 can help to maintain plant integrity in the tested cultivar under drought stress.
