We have investigated the diurnal variations of the pCO2 and related environmental factors in the cascade reservoirs with different trophic levels along Wujiang River. In surface water the pCO2 was 357±11 μatm in...We have investigated the diurnal variations of the pCO2 and related environmental factors in the cascade reservoirs with different trophic levels along Wujiang River. In surface water the pCO2 was 357±11 μatm in Hong-jiadu Reservoir, 338±48 μatm in Dongfeng Reservoir, 682±303 μatm in Wujiangdu Reservoir, and 1677±429 μatm in Liuguang, respectively. The results indicated that these cascade reservoirs had much lower pCO2 values in surface water than river did, and hypereutrophic reservoir showed larger diurnal variations of pCO2 than meso-eutrophic reservoir. In water column, pCO2 tended to increase with the depth. Phytoplankton and the environmental factors such as temperature and pH had different influences on pCO2 diurnal variations due to different trophic levels, and the effect of phytoplankton on pCO2 variation increased with the increase of trophic level in these reservoirs.展开更多
Carotenoids are important nutrients for human health that must be obtained from plants since they cannot be biosynthesized by the human body.Dissecting the regulatory mechanism of carotenoid metabolism in plants repre...Carotenoids are important nutrients for human health that must be obtained from plants since they cannot be biosynthesized by the human body.Dissecting the regulatory mechanism of carotenoid metabolism in plants represents the first step toward manipulating carotenoid contents in plants by molecular design breeding.In this study,we determined that SlAP2c,an APETALA2(AP2)family member,acts as a transcriptional repressor to regulate carotenoid biosynthesis in tomato(Solanum lycopersicum).Knockout of SlAP2c in both the“Micro Tom”and“Ailsa Craig”backgrounds resulted in greater lycopene accumulation,whereas overexpression of this gene led to orange-ripe fruit with significantly lower lycopene contents than the wild type.We established that SlAP2c represses the expression of genes involved in lycopene biosynthesis by directly binding to the cis-elements in their promoters.Moreover,SlAP2c relies on its EAR motif to recruit the co-repressors TOPLESS(TPL)2/4 and forms a complex with histone deacetylase(had)1/3,thereby reducing the histone acetylation levels of lycopene biosynthesis genes.Furthermore,SlAP2a,a homolog of SlAP2c,acts upstream of SlAP2c and alleviates the SlAP2c-induced repression of lycopene biosynthesis genes by inhibiting SlAP2c transcription during fruit ripening.Therefore,we identified a transcriptional cascade mediated by AP2 family members that regulates lycopene biosynthesis during fruit ripening in tomato,laying the foundation for the manipulation of carotenoid metabolism in plants.展开更多
Construction of multi-enzyme complexes not only can help expand the understanding of biological mechanisms, but also holds great promise in biosynthesis, biosensing and biomedicine. Herein, a hybrid multi-enzyme syste...Construction of multi-enzyme complexes not only can help expand the understanding of biological mechanisms, but also holds great promise in biosynthesis, biosensing and biomedicine. Herein, a hybrid multi-enzyme system, CeO2/glucose oxidase(GOx) nanocomplex was developed via self-assembly and exhibited excellent catalytic activity toward cascade reactions. Compared to mixed GOx and CeO2, the nanocomplexes displayed enhanced efficiency, mainly attributed to the minimal diffusion of intermediate in the nanocomplexes system. Moreover, the nanocomplexes exhibited outstanding long-term stability and excellent recyclability. Benefiting from these merits, a highly sensitive and selective biosensor for colorimetric detection of glucose was constructed based on CeO2/GOx nanocomplexes. Such a self-assembled nanozyme complex offers a simple and efficient example to build spatially confined multi-enzyme systems to potentiate their applications in energy conversion,detoxification and bioanalysis.展开更多
Mitogen-activated protein kinases(MPKs)play essential roles in guard cell signaling,but whether MPK cascades participate in guard cell ethylene signaling and interact with hydrogen peroxide(H2O2),nitric oxide(NO),and ...Mitogen-activated protein kinases(MPKs)play essential roles in guard cell signaling,but whether MPK cascades participate in guard cell ethylene signaling and interact with hydrogen peroxide(H2O2),nitric oxide(NO),and ethylene-signaling components remain unclear.Here,we report that ethylene activated MPK3 and MPK6 in the leaves of wild-type Arabidopsis thaliana as well as ethylene insensitive2(ein2),ein3,nitrate reductase1(nia1),and nia2 mutants,but this effect was impaired in ethylene response1(etr1),nicotinamide adenine dinucleotide phosphate oxidase AtrbohF,mpk kinase1(mkk1),and mkk3 mutants.By contrast,the constitutive triple response1(ctr1)mutant had constitutively active MPK3 and MPK6.Yeast two-hybrid,bimolecular fluorescence complementation,and pull-down assays indicated that MPK3 and MPK6 physically interacted with MKK1,MKK3,and the C-terminal region of EIN2(EIN2 CEND).mkk1,mkk3,mpk3,and mpk6 mutants had typical levels of ethylene-induced H2O2 generation but impaired ethylene-induced EIN2 CEND cleavage and nuclear translocation,EIN3 protein accumulation,NO production in guard cells,and stomatal closure.These results show that the MKK1/3–MPK3/6 cascade mediates ethylene-induced stomatal closure by functioning downstream of ETR1,CTR1,and H2O2 to interact with EIN2,thereby promoting EIN3 accumulation and EIN3-dependent NO production in guard cells.展开更多
A new and efficient cascade synthesis of polycyclic fused imidazo[2,1-b][1,3]thiazinones has been developed. This protocol includes an intermolecular N-acylation followed by a copper-catalyzed intramolecular C--S coup...A new and efficient cascade synthesis of polycyclic fused imidazo[2,1-b][1,3]thiazinones has been developed. This protocol includes an intermolecular N-acylation followed by a copper-catalyzed intramolecular C--S coupling reaction. The methodology is applied to a wide range of 2-iodo, 2-bromo, and 2-chloro benzoyl chlorides to yield the polycyclic fused imidazo[2,1-b][ 1,3]thiazinones in good to excellent yields.展开更多
基金supported by the Foundation of Chinese Academy of Sciences (Grant No. kzcx2-yw-137)National Natural Science Foundation of China (Grant Nos. 40721002 and 90610037)
文摘We have investigated the diurnal variations of the pCO2 and related environmental factors in the cascade reservoirs with different trophic levels along Wujiang River. In surface water the pCO2 was 357±11 μatm in Hong-jiadu Reservoir, 338±48 μatm in Dongfeng Reservoir, 682±303 μatm in Wujiangdu Reservoir, and 1677±429 μatm in Liuguang, respectively. The results indicated that these cascade reservoirs had much lower pCO2 values in surface water than river did, and hypereutrophic reservoir showed larger diurnal variations of pCO2 than meso-eutrophic reservoir. In water column, pCO2 tended to increase with the depth. Phytoplankton and the environmental factors such as temperature and pH had different influences on pCO2 diurnal variations due to different trophic levels, and the effect of phytoplankton on pCO2 variation increased with the increase of trophic level in these reservoirs.
基金supported in part by the National Natural Science Foundation of China(no.32372780,no.32172643)the Applied Basic Research Category of Science and Technology Program of Sichuan Province(2021YFQ0071,2022YFSY0059-1,2021YFYZ00105-LH)+2 种基金the Technology Innovation and Application Development Program of Chongqing(cstc2021jscx-cylh X0001)the Natural Science Foundation of Sichuan Province,China(2023NSFSC1991)the Institutional Research Funding of Sichuan University(2022SCUNL105)。
文摘Carotenoids are important nutrients for human health that must be obtained from plants since they cannot be biosynthesized by the human body.Dissecting the regulatory mechanism of carotenoid metabolism in plants represents the first step toward manipulating carotenoid contents in plants by molecular design breeding.In this study,we determined that SlAP2c,an APETALA2(AP2)family member,acts as a transcriptional repressor to regulate carotenoid biosynthesis in tomato(Solanum lycopersicum).Knockout of SlAP2c in both the“Micro Tom”and“Ailsa Craig”backgrounds resulted in greater lycopene accumulation,whereas overexpression of this gene led to orange-ripe fruit with significantly lower lycopene contents than the wild type.We established that SlAP2c represses the expression of genes involved in lycopene biosynthesis by directly binding to the cis-elements in their promoters.Moreover,SlAP2c relies on its EAR motif to recruit the co-repressors TOPLESS(TPL)2/4 and forms a complex with histone deacetylase(had)1/3,thereby reducing the histone acetylation levels of lycopene biosynthesis genes.Furthermore,SlAP2a,a homolog of SlAP2c,acts upstream of SlAP2c and alleviates the SlAP2c-induced repression of lycopene biosynthesis genes by inhibiting SlAP2c transcription during fruit ripening.Therefore,we identified a transcriptional cascade mediated by AP2 family members that regulates lycopene biosynthesis during fruit ripening in tomato,laying the foundation for the manipulation of carotenoid metabolism in plants.
基金supported by the National Natural Science Foundation of China(No.21675120)National Key R&D Program of China(No.2017YFA0208000)+1 种基金Ten Thousand Talents Program for Young Talentsthe Large-scale Instrument and Equipment Sharing Foundation of Wuhan University
文摘Construction of multi-enzyme complexes not only can help expand the understanding of biological mechanisms, but also holds great promise in biosynthesis, biosensing and biomedicine. Herein, a hybrid multi-enzyme system, CeO2/glucose oxidase(GOx) nanocomplex was developed via self-assembly and exhibited excellent catalytic activity toward cascade reactions. Compared to mixed GOx and CeO2, the nanocomplexes displayed enhanced efficiency, mainly attributed to the minimal diffusion of intermediate in the nanocomplexes system. Moreover, the nanocomplexes exhibited outstanding long-term stability and excellent recyclability. Benefiting from these merits, a highly sensitive and selective biosensor for colorimetric detection of glucose was constructed based on CeO2/GOx nanocomplexes. Such a self-assembled nanozyme complex offers a simple and efficient example to build spatially confined multi-enzyme systems to potentiate their applications in energy conversion,detoxification and bioanalysis.
基金supported by the National Natural Science Foundation of China(31570397,31870375)the Natural Science Research Plan of Shaanxi Province of China(2016JZ008)the Excellent Doctoral Dissertation Project of Shaanxi Normal University(2017TS037).
文摘Mitogen-activated protein kinases(MPKs)play essential roles in guard cell signaling,but whether MPK cascades participate in guard cell ethylene signaling and interact with hydrogen peroxide(H2O2),nitric oxide(NO),and ethylene-signaling components remain unclear.Here,we report that ethylene activated MPK3 and MPK6 in the leaves of wild-type Arabidopsis thaliana as well as ethylene insensitive2(ein2),ein3,nitrate reductase1(nia1),and nia2 mutants,but this effect was impaired in ethylene response1(etr1),nicotinamide adenine dinucleotide phosphate oxidase AtrbohF,mpk kinase1(mkk1),and mkk3 mutants.By contrast,the constitutive triple response1(ctr1)mutant had constitutively active MPK3 and MPK6.Yeast two-hybrid,bimolecular fluorescence complementation,and pull-down assays indicated that MPK3 and MPK6 physically interacted with MKK1,MKK3,and the C-terminal region of EIN2(EIN2 CEND).mkk1,mkk3,mpk3,and mpk6 mutants had typical levels of ethylene-induced H2O2 generation but impaired ethylene-induced EIN2 CEND cleavage and nuclear translocation,EIN3 protein accumulation,NO production in guard cells,and stomatal closure.These results show that the MKK1/3–MPK3/6 cascade mediates ethylene-induced stomatal closure by functioning downstream of ETR1,CTR1,and H2O2 to interact with EIN2,thereby promoting EIN3 accumulation and EIN3-dependent NO production in guard cells.
基金Project supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions, the National Natural Science Foundation of China （Nos. 21072168, 21102009） and Natural Science Foundation of Jiangsu Province （No. B K2011230）.
文摘A new and efficient cascade synthesis of polycyclic fused imidazo[2,1-b][1,3]thiazinones has been developed. This protocol includes an intermolecular N-acylation followed by a copper-catalyzed intramolecular C--S coupling reaction. The methodology is applied to a wide range of 2-iodo, 2-bromo, and 2-chloro benzoyl chlorides to yield the polycyclic fused imidazo[2,1-b][ 1,3]thiazinones in good to excellent yields.
