In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic...In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic(HRP-U),acid(HRP-C)and alkali(HRP-A)assisted extraction methods were investigated.The results demonstrated that extraction methods had significant effects on extraction yield,monosaccharide composition,molecular weight,particle size,triple-helical structure,and surface morphology of HRPs except for the major linkage bands.Thermogravimetric analysis showed that HRP-U with filamentous reticular microstructure exhibited better thermal stability.The HRP-A with the lowest molecular weight and highest arabinose content possessed the best antioxidant activities.Moreover,the rheological analysis indicated that HRPs with higher galacturonic acid content and molecular weight showed higher viscosity and stronger crosslinking network(HRP-C,HRP-W and HRP-U),which exhibited stronger bile acid binding capacity.The present findings provide scientific evidence in the preparation technology of sea buckthorn polysaccharides with good antioxidant and bile acid binding capacity which are related to the structure affected by the extraction methods.展开更多
Soymilk is a natural nanocarrier.However,the performance of flavonoid-soymilk nano-complex remains unclear.In this work,icariin-soymilk nano-complexes(ISNCs)were successfully fabricated and characterized.The effects o...Soymilk is a natural nanocarrier.However,the performance of flavonoid-soymilk nano-complex remains unclear.In this work,icariin-soymilk nano-complexes(ISNCs)were successfully fabricated and characterized.The effects of high-pressure homogenization(HPH)treatment on structure and physicochemical properties of soymilk and nano-complexes were investigated.HPH treatment could significantly improve the surface hydrophobicity and interfacial activity of soymilk.The soymilk with HPH treatment could significantly improve the water solubility(20 folds),thermal stability and bioavailability of icariin.The highest encapsulation efficiency(93.28%),loading capacity(39.09μg/mg),ζ-potentia(absolute value,31.20 mV)and bioavailability(72.14%)were observed in HSI-200(200 bar of homogenization pressure).While HSI-500(500 bar of homogenization pressure)showed the smallest particle size(183.73 nm).ISNCs showed a rougher surface and an irregular lamellar structure with large amount of fine particles by using Cryo-SEM,suggesting that icariin was encapsulated in soymilk.These data supplied a novel strategy to improve the performance of icariin in functional foods.展开更多
Mitogen-activated protein kinase(MAPK/MPK)cascades play crucial parts in plant growth,development processes,immune ability,and stress responses;however,the regulatory mechanism by which MAPK affects fruit ripening rem...Mitogen-activated protein kinase(MAPK/MPK)cascades play crucial parts in plant growth,development processes,immune ability,and stress responses;however,the regulatory mechanism by which MAPK affects fruit ripening remains largely unexplored.Here,we reported that MaMPK14 cooperated with MaMYB4 to mediate postharvest banana fruit ripening.Transient overexpression of individual MaMPK14 and MaMYB4 in banana fruit delayed fruit ripening,confirming the negative roles in the ripening.The ripening negative regulator MaMYB4 could repress the transcription of genes associated with ethylene biosynthesis and fruit softening,such as MaACS1,MaXTH5,MaPG3,and MaEXPA15.Furthermore,MaMPK14 phosphorylated MaMYB4 at Ser160 via a direct interaction.Mutation at Ser160 of MaMYB4 reduced its interaction with MaMPK14 but did not affect its subcellular localization.Importantly,phosphorylation of MaMYB4 by MaMPK14 enhanced the MaMYB4-mediated transcriptional inhibition,binding strength,protein stability,and the repression of fruit ripening.Taken together,our results delineated the regulation pathway of MAPK module during banana fruit ripening,which involved the phosphorylation modification of MaMYB4 mediated by MaMPK14.展开更多
The cytochrome b_(6f)(Cyt b_(6f))complex is a multisubunit protein complex in chloroplast thylakoid membranes required for photosynthetic electron transport.Here we report the isolation and characterization of the new...The cytochrome b_(6f)(Cyt b_(6f))complex is a multisubunit protein complex in chloroplast thylakoid membranes required for photosynthetic electron transport.Here we report the isolation and characterization of the new tiny albino 1(nta1)mutant in Arabidopsis,which has severe defects in Cyt b_(6f) accumulation and chloroplast development.Gene cloning revealed that the nta1 phenotype was caused by disruption of a single nuclear gene,NTA1,which encodes an integral thylakoid membrane protein conserved across green algae and plants.Overexpression of NTA1 completely rescued the nta1 phenotype,and knockout of NTA1 in wild-type plants recapitulated the mutant phenotype.Loss of NTA1 function severely impaired the accumulation of multiprotein complexes related to photosynthesis in thylakoid membranes,particularly the components of Cyt b_(6f).NTA1 was shown to directly interact with four subunits(Cyt b6/PetB,PetD,PetG,and PetN)of Cyt b_(6f) through the DUF1279 domain and C-terminal sequence to mediate their assembly.Taken together,our results identify NTA1 as a new and key regulator of chloroplast development that plays essential roles in assembly of the Cyt b_(6f) complex by interacting with multiple Cyt b_(6f) subunits.展开更多
The alternative splicing of select genes is an important mechanism to regulate responses to endogenous and environmental signals in plants.However,the role of alternative splicing in regulating fruit ripening remains ...The alternative splicing of select genes is an important mechanism to regulate responses to endogenous and environmental signals in plants.However,the role of alternative splicing in regulating fruit ripening remains unclear.Here,we discovered that MaMYB16L,an R1-type MYB transcription factor,undergoes alternative splicing and generates two transcripts,the full-length isoform MaMYB16L and a truncated form MaMYB16S,in banana fruit.During banana fruit ripening,the alternative splicing process intensifies with downregulated MaMYB16L and upregulated MaMYB16S.Moreover,MaMYB16L is a transcriptional repressor that directly binds with the promoters of many genes associated with starch degradation and MaDREB2,a positive ripening regulator,and represses their expression.In contrast,MaMBY16S lacks a DNA-binding domain but competitively combines and forms non-functional heterodimers with functional MaMYB16L.MaMYB16L-MaMYB16S heterodimers decrease the binding capacity and transrepression activity of MaMYB16L.The downregulation of MaMYB16L and the upregulation of MaMYB16S,that is,a decreased ratio of active to non-active isoforms,facilitates the activation of ripening-related genes and thereby promotes fruit ripening.Furthermore,the transient overexpression of MaMYB16S promotes banana fruit ripening,whereas the overexpression of MaMYB16L delays this process.Therefore,the alternative splicing of MaMYB16L might generate a self-controlled regulatory loop to regulate banana fruit ripening.展开更多
Pericarp browning is the major cause of deterioration of harvested litchi fruit.Water loss plays a role in pericarp browning of litchi fruit.This study investigated the effects of humidification with dry fog on perica...Pericarp browning is the major cause of deterioration of harvested litchi fruit.Water loss plays a role in pericarp browning of litchi fruit.This study investigated the effects of humidification with dry fog on pericarp browning and quality of litchi fruit stored at low temperature.Litchi fruit were stored in a non-humidified cold chamber(control)or in a humidified cold room using Tabor atomizer system that generated 95%relative humidity(RH)without depositing water on the fruit surface at 4℃.Control fruit stored in cold room without added humidity underwent rapid weight loss,accompanied by severe pericarp browning after 25 d of storage.However,slight weight loss and no obvious pericarp browning were found in humidified-fruit.Moreover,humidification maintained well the integrity of cell membrane and inhibited polyphenol oxidase activity during early storage.In addition,respiration rate was obviously inhibited in humidified-fruit compared with control fruit.This study might provide a convenient approach to reduce pericarp browning of harvested litchi fruit by humidifying the fruit using the Tabor atomizer at low temperature instead of packaging with film.展开更多
基金The Guangdong Basic and Applied Basic Research Foundation(2022A1515010730)National Natural Science Foundation of China(32001647)+2 种基金National Natural Science Foundation of China(31972022)Financial and moral assistance supported by the Guangdong Basic and Applied Basic Research Foundation(2019A1515011996)111 Project(B17018)。
文摘In this study,the structural characters,antioxidant activities and bile acid-binding ability of sea buckthorn polysaccharides(HRPs)obtained by the commonly used hot water(HRP-W),pressurized hot water(HRP-H),ultrasonic(HRP-U),acid(HRP-C)and alkali(HRP-A)assisted extraction methods were investigated.The results demonstrated that extraction methods had significant effects on extraction yield,monosaccharide composition,molecular weight,particle size,triple-helical structure,and surface morphology of HRPs except for the major linkage bands.Thermogravimetric analysis showed that HRP-U with filamentous reticular microstructure exhibited better thermal stability.The HRP-A with the lowest molecular weight and highest arabinose content possessed the best antioxidant activities.Moreover,the rheological analysis indicated that HRPs with higher galacturonic acid content and molecular weight showed higher viscosity and stronger crosslinking network(HRP-C,HRP-W and HRP-U),which exhibited stronger bile acid binding capacity.The present findings provide scientific evidence in the preparation technology of sea buckthorn polysaccharides with good antioxidant and bile acid binding capacity which are related to the structure affected by the extraction methods.
基金the financial support from Youth Innovation Promotion Association,Chinese Academy of Sciences(2022353)Guangdong Basic and Applied Basic Research Foundation(2020A1515011025)Science and Technology Planning Project of Guangdong Province(2022A0505050055)。
文摘Soymilk is a natural nanocarrier.However,the performance of flavonoid-soymilk nano-complex remains unclear.In this work,icariin-soymilk nano-complexes(ISNCs)were successfully fabricated and characterized.The effects of high-pressure homogenization(HPH)treatment on structure and physicochemical properties of soymilk and nano-complexes were investigated.HPH treatment could significantly improve the surface hydrophobicity and interfacial activity of soymilk.The soymilk with HPH treatment could significantly improve the water solubility(20 folds),thermal stability and bioavailability of icariin.The highest encapsulation efficiency(93.28%),loading capacity(39.09μg/mg),ζ-potentia(absolute value,31.20 mV)and bioavailability(72.14%)were observed in HSI-200(200 bar of homogenization pressure).While HSI-500(500 bar of homogenization pressure)showed the smallest particle size(183.73 nm).ISNCs showed a rougher surface and an irregular lamellar structure with large amount of fine particles by using Cryo-SEM,suggesting that icariin was encapsulated in soymilk.These data supplied a novel strategy to improve the performance of icariin in functional foods.
基金This work was funded by the National Natural Science Foundation of China(Grant No.31830071)China Agriculture Research System of Ministry of Finance(MOF)and Ministry of Agriculture and Rural affairs(MARA)(Grant No.CARS-31).
文摘Mitogen-activated protein kinase(MAPK/MPK)cascades play crucial parts in plant growth,development processes,immune ability,and stress responses;however,the regulatory mechanism by which MAPK affects fruit ripening remains largely unexplored.Here,we reported that MaMPK14 cooperated with MaMYB4 to mediate postharvest banana fruit ripening.Transient overexpression of individual MaMPK14 and MaMYB4 in banana fruit delayed fruit ripening,confirming the negative roles in the ripening.The ripening negative regulator MaMYB4 could repress the transcription of genes associated with ethylene biosynthesis and fruit softening,such as MaACS1,MaXTH5,MaPG3,and MaEXPA15.Furthermore,MaMPK14 phosphorylated MaMYB4 at Ser160 via a direct interaction.Mutation at Ser160 of MaMYB4 reduced its interaction with MaMPK14 but did not affect its subcellular localization.Importantly,phosphorylation of MaMYB4 by MaMPK14 enhanced the MaMYB4-mediated transcriptional inhibition,binding strength,protein stability,and the repression of fruit ripening.Taken together,our results delineated the regulation pathway of MAPK module during banana fruit ripening,which involved the phosphorylation modification of MaMYB4 mediated by MaMPK14.
基金supported by the General Research Fund(CUHK codes 14121915,14148916,and 14104521)the Area of Excellence Scheme(AoE/M-403/16 and AoE/M-05/12)of the Research Grants Council(RGC)of Hong Kong+1 种基金the National Natural Science Foundation of China(NSFC)-RGC Joint Scheme(N_CUHK452/17)direct grants from the Chinese University of Hong Kong(CUHK).
文摘The cytochrome b_(6f)(Cyt b_(6f))complex is a multisubunit protein complex in chloroplast thylakoid membranes required for photosynthetic electron transport.Here we report the isolation and characterization of the new tiny albino 1(nta1)mutant in Arabidopsis,which has severe defects in Cyt b_(6f) accumulation and chloroplast development.Gene cloning revealed that the nta1 phenotype was caused by disruption of a single nuclear gene,NTA1,which encodes an integral thylakoid membrane protein conserved across green algae and plants.Overexpression of NTA1 completely rescued the nta1 phenotype,and knockout of NTA1 in wild-type plants recapitulated the mutant phenotype.Loss of NTA1 function severely impaired the accumulation of multiprotein complexes related to photosynthesis in thylakoid membranes,particularly the components of Cyt b_(6f).NTA1 was shown to directly interact with four subunits(Cyt b6/PetB,PetD,PetG,and PetN)of Cyt b_(6f) through the DUF1279 domain and C-terminal sequence to mediate their assembly.Taken together,our results identify NTA1 as a new and key regulator of chloroplast development that plays essential roles in assembly of the Cyt b_(6f) complex by interacting with multiple Cyt b_(6f) subunits.
基金supported by the National Natural Science Foundation of China(Nos.31830070,31871856,31772041)the Science and Technology Planning Project of Guangzhou(Nos.201804020041,201904010014)National Basic Research Program of China(No.2013CB127104).
文摘The alternative splicing of select genes is an important mechanism to regulate responses to endogenous and environmental signals in plants.However,the role of alternative splicing in regulating fruit ripening remains unclear.Here,we discovered that MaMYB16L,an R1-type MYB transcription factor,undergoes alternative splicing and generates two transcripts,the full-length isoform MaMYB16L and a truncated form MaMYB16S,in banana fruit.During banana fruit ripening,the alternative splicing process intensifies with downregulated MaMYB16L and upregulated MaMYB16S.Moreover,MaMYB16L is a transcriptional repressor that directly binds with the promoters of many genes associated with starch degradation and MaDREB2,a positive ripening regulator,and represses their expression.In contrast,MaMBY16S lacks a DNA-binding domain but competitively combines and forms non-functional heterodimers with functional MaMYB16L.MaMYB16L-MaMYB16S heterodimers decrease the binding capacity and transrepression activity of MaMYB16L.The downregulation of MaMYB16L and the upregulation of MaMYB16S,that is,a decreased ratio of active to non-active isoforms,facilitates the activation of ripening-related genes and thereby promotes fruit ripening.Furthermore,the transient overexpression of MaMYB16S promotes banana fruit ripening,whereas the overexpression of MaMYB16L delays this process.Therefore,the alternative splicing of MaMYB16L might generate a self-controlled regulatory loop to regulate banana fruit ripening.
基金This work was supported by National Key R&D Program of China(No.2018YFD0401301)National Natural Science Foundation of China(Nos 31770726 and 31772041)+3 种基金Science and Technology Planning of Jiangsu Province(No.BZ2013004)Science and Technology Planning Project of Guangzhou(No.201804020041)Agro-scientific Research in the Public Interest(No.201303073)The work was also supported by National Botanical Gardens,CAS.
文摘Pericarp browning is the major cause of deterioration of harvested litchi fruit.Water loss plays a role in pericarp browning of litchi fruit.This study investigated the effects of humidification with dry fog on pericarp browning and quality of litchi fruit stored at low temperature.Litchi fruit were stored in a non-humidified cold chamber(control)or in a humidified cold room using Tabor atomizer system that generated 95%relative humidity(RH)without depositing water on the fruit surface at 4℃.Control fruit stored in cold room without added humidity underwent rapid weight loss,accompanied by severe pericarp browning after 25 d of storage.However,slight weight loss and no obvious pericarp browning were found in humidified-fruit.Moreover,humidification maintained well the integrity of cell membrane and inhibited polyphenol oxidase activity during early storage.In addition,respiration rate was obviously inhibited in humidified-fruit compared with control fruit.This study might provide a convenient approach to reduce pericarp browning of harvested litchi fruit by humidifying the fruit using the Tabor atomizer at low temperature instead of packaging with film.
