Two kinds of regression equations are used to reproduce the sediment flux of the 26 small coastal watersheds in southeastern China.The first kind is the global equations suggested by Milliman and Syvitski(1992),Mulder...Two kinds of regression equations are used to reproduce the sediment flux of the 26 small coastal watersheds in southeastern China.The first kind is the global equations suggested by Milliman and Syvitski(1992),Mulder and Syvitski(1996),Syvitski et al.(2003),and Syvitski and Milliman(2007).The second kind is the modified equations revised by the characteristics of the coastal watersheds,including the drainage area,mean water discharge,and mean sediment discharge.Compared with the observations of the hydrometric stations,the global equations overestimate the sediment flux by 1–2 orders of magnitude.By using the modified equations,the accuracy of the estimated sediment flux is significantly improved,with the relative error in the range of 7%–24%.The reason for the overestimation mainly caused by different parameters’domain and regression coefficients between global rivers and study coastal watersheds.This study demonstrates that modification needs to be considered when using global regression equations to reproduce the sediment flux of the small coastal watersheds in southeastern China.展开更多
Activity-based Ubiquitin probes(Ub-ABPs)carrying a reporter group have emerged as effective tools for the investigation of deubiquitinating enzymes(DUBs),such as studying the molecular mechanism of DUBs,profiling new ...Activity-based Ubiquitin probes(Ub-ABPs)carrying a reporter group have emerged as effective tools for the investigation of deubiquitinating enzymes(DUBs),such as studying the molecular mechanism of DUBs,profiling new DUBs.But so far,the synthesis of commonly used biotin-bearing Ub-ABPs is a technical challenge.Here,we report a one-pot semi-synthetic strategy for the acquiring of Ub-ABPs carrying a biotin tag through sequential enzymatic ligation,N-S acyl transfer and aminolysis reaction without any purification steps.These probes enable to capture the different family of DUBs for enrichment and immunoblotting using the attached biotin tag.展开更多
Topographic/bathymetric conditions of the continental shelf can significantly influence the long-term growth of river deltas.In particular,these conditions constrain the accommodation space for sedimentation in the de...Topographic/bathymetric conditions of the continental shelf can significantly influence the long-term growth of river deltas.In particular,these conditions constrain the accommodation space for sedimentation in the deltaic areas.In this study,we use a conceptual geometric model to evaluate the role played by this factor,on the basis of the principle of mass conservation.The Ganges-Brahmaputra,Mekong and Nile deltas are examined as three typical examples,in terms of their different original seabed morphologies.The control variate method is applied to eliminate the effect of the difference in model input variables.The results show that,assuming a constant sediment load,the delta growth rate will decrease with time;a higher value of the original seabed slope leads to a lower shoreline progradation rate for the subaerial delta and a higher growth rate for the subaqueous delta.Thus,the original seabed morphology represented by slope is a critical factor affecting the evolution of Holocene large-river deltas.These results explain the interrelationships between sediment load,deltaic plain area,and the original seabed slopes for the 27 large-river deltas worldwide,located in the middle/low latitudes,with different tectonic backgrounds.In the future,the conceptual geometric model may be combined with sediment dynamic modeling to identify more details of the evolution of these deltas.展开更多
Pib is a well-characterized rice blast-resistance gene belonging to the nucleotide binding site (NBS) and leucine-rich repeat (LRR) superfamily.Expression of Pib was low under non-challenged conditions,but strongly in...Pib is a well-characterized rice blast-resistance gene belonging to the nucleotide binding site (NBS) and leucine-rich repeat (LRR) superfamily.Expression of Pib was low under non-challenged conditions,but strongly induced by the blast-causing fungal pathogen Magnaporthe grisea,thereby conferring resistance to the pathogen.It is generally established that cytosine methylation of the promoter-region often plays a repressive role in modulating expression of the gene in question.We report here that two critical regions of the Pib promoter were heavily CG cytosine-methylated in both cultivars studied.Surprisingly,induced expression of Pib by M.grisea infection did not entail its promoter demethylation,and partial demethylation by 5-azacytidine-treatment actually reduced Pib expression relative to wildtype plants.Accordingly,the blast disease-resistance was compromised in the 5-azaC-treated plants relative to wild-type.In contrast,the disease susceptibility was not affected by the 5-azaC treatment in another two rice cultivars that did not contain the Pib gene,ruling out effects of other R genes and non-specific genotoxic effects by the drug-treatment as a cause for the compromised Pib-conditioned blast-resistance.Taken together,our results suggest that promoter DNA methylation plays a novel enhancing role in conditioning high-level of induced expression of the Pib gene in times of M.grisea infection,and its conferred resistance to the pathogen.展开更多
基金supported by the National Natural Science Foundation of China(71771071,72101246)the China Postdoctoral Science Foundation(2019M662210)the Fundamental Research Funds for the Central Universities(JZ2023HGTB0286,WK2040000024)。
基金The National Natural Science Foundation of China under contract Nos 41625021,41676079 and 41906021the Project of Enhancing School with Innovation of Guangdong Ocean University under contract No.Q18307the Program for Scientific Research Start-up Funds of Guangdong Ocean University under contract No.060302112010
文摘Two kinds of regression equations are used to reproduce the sediment flux of the 26 small coastal watersheds in southeastern China.The first kind is the global equations suggested by Milliman and Syvitski(1992),Mulder and Syvitski(1996),Syvitski et al.(2003),and Syvitski and Milliman(2007).The second kind is the modified equations revised by the characteristics of the coastal watersheds,including the drainage area,mean water discharge,and mean sediment discharge.Compared with the observations of the hydrometric stations,the global equations overestimate the sediment flux by 1–2 orders of magnitude.By using the modified equations,the accuracy of the estimated sediment flux is significantly improved,with the relative error in the range of 7%–24%.The reason for the overestimation mainly caused by different parameters’domain and regression coefficients between global rivers and study coastal watersheds.This study demonstrates that modification needs to be considered when using global regression equations to reproduce the sediment flux of the small coastal watersheds in southeastern China.
基金supported by the National Key R&D Program of China(No.2017YFA0505400)the National Natural Science Foundation of China(Nos.21877024,21972214 and 22277020)。
文摘Activity-based Ubiquitin probes(Ub-ABPs)carrying a reporter group have emerged as effective tools for the investigation of deubiquitinating enzymes(DUBs),such as studying the molecular mechanism of DUBs,profiling new DUBs.But so far,the synthesis of commonly used biotin-bearing Ub-ABPs is a technical challenge.Here,we report a one-pot semi-synthetic strategy for the acquiring of Ub-ABPs carrying a biotin tag through sequential enzymatic ligation,N-S acyl transfer and aminolysis reaction without any purification steps.These probes enable to capture the different family of DUBs for enrichment and immunoblotting using the attached biotin tag.
基金supported by the National Natural Science Foundation of China(Grant Nos.41625021,41906021,and 41676079)the Program for Scientific Research Start-up Funds of Guangdong Ocean University。
文摘Topographic/bathymetric conditions of the continental shelf can significantly influence the long-term growth of river deltas.In particular,these conditions constrain the accommodation space for sedimentation in the deltaic areas.In this study,we use a conceptual geometric model to evaluate the role played by this factor,on the basis of the principle of mass conservation.The Ganges-Brahmaputra,Mekong and Nile deltas are examined as three typical examples,in terms of their different original seabed morphologies.The control variate method is applied to eliminate the effect of the difference in model input variables.The results show that,assuming a constant sediment load,the delta growth rate will decrease with time;a higher value of the original seabed slope leads to a lower shoreline progradation rate for the subaerial delta and a higher growth rate for the subaqueous delta.Thus,the original seabed morphology represented by slope is a critical factor affecting the evolution of Holocene large-river deltas.These results explain the interrelationships between sediment load,deltaic plain area,and the original seabed slopes for the 27 large-river deltas worldwide,located in the middle/low latitudes,with different tectonic backgrounds.In the future,the conceptual geometric model may be combined with sediment dynamic modeling to identify more details of the evolution of these deltas.
基金supported by the State Key Basic Research and Development Plan of China(2011CB100205)the Program for Introducing Talents to Universities(B07017)
文摘Pib is a well-characterized rice blast-resistance gene belonging to the nucleotide binding site (NBS) and leucine-rich repeat (LRR) superfamily.Expression of Pib was low under non-challenged conditions,but strongly induced by the blast-causing fungal pathogen Magnaporthe grisea,thereby conferring resistance to the pathogen.It is generally established that cytosine methylation of the promoter-region often plays a repressive role in modulating expression of the gene in question.We report here that two critical regions of the Pib promoter were heavily CG cytosine-methylated in both cultivars studied.Surprisingly,induced expression of Pib by M.grisea infection did not entail its promoter demethylation,and partial demethylation by 5-azacytidine-treatment actually reduced Pib expression relative to wildtype plants.Accordingly,the blast disease-resistance was compromised in the 5-azaC-treated plants relative to wild-type.In contrast,the disease susceptibility was not affected by the 5-azaC treatment in another two rice cultivars that did not contain the Pib gene,ruling out effects of other R genes and non-specific genotoxic effects by the drug-treatment as a cause for the compromised Pib-conditioned blast-resistance.Taken together,our results suggest that promoter DNA methylation plays a novel enhancing role in conditioning high-level of induced expression of the Pib gene in times of M.grisea infection,and its conferred resistance to the pathogen.
