Nata de coco is a traditional fermented food,chemically known as bacterial cellulose(BC),widely used in the food industry,personal care,and biomaterial areas.In the nata de coco industry,microbiota-fermented coconut w...Nata de coco is a traditional fermented food,chemically known as bacterial cellulose(BC),widely used in the food industry,personal care,and biomaterial areas.In the nata de coco industry,microbiota-fermented coconut water(FCW)has been regarded as a highly efficient medium for improving BC synthesis by Komagataeibacter spp.However,its effects on the biological properties of the strains of Komagataeibacter and structural characteristics of BC remain unknown,resulting in unstable production and BC quality.This study aimed to explore the biological properties of K.nataicola,the characteristics of BC structure and reasons for the efficiency under the effect of FCW.The results showed that FCW could increase the BC yield of K.nataicola by 2.03-4.75 times,the uridine diphosphate glucose pyrophosphorylase activity by 10-45.3 times,and the hexokinase,phosphofructokinase,or pyruvate kinase activities by 2 times.The extracellular metabolite profile of K.nataicola showed that its glycolysis/gluconeogenesis pathway was significantly stimulated and the utilization of erythritol obviously increased.These phenomena might be attributed to the use of ethanol,lactate,xylitoland mannitol in FCW by K.nataicola.In addition,the structural characteristics of BC produced in FCW included higher number of hydrogen bonds,thinner fibrils,a looser three-dimensional network,improved porosity and greater mechanical strength.This study offered novel insights into the BC synthesis of K.nataicola and the BC structural characteristics cultivated in FCW,providing valuable references for the efficient production and potential applications of both nata de coco and BC.展开更多
The authors regrets that there were certain errors in the published article which detailed below.Correction to the original text in the Abstract:“The KEGG pathway analysis of differential metabolites showed that the ...The authors regrets that there were certain errors in the published article which detailed below.Correction to the original text in the Abstract:“The KEGG pathway analysis of differential metabolites showed that the GPb4103 hindered BC synthesis of the JY6211 by altering accu-mulation of metabolites in the fermentation broth through metabolic pathways.”Corrected text is as follows:The KEGG pathway analysis of differential metabolites showed that the GPb4103 hindered BC synthesis of the JY6211 by altering accu-mulation of metabolites in the fermentation broth through BC anabo-lism pathway.展开更多
Nata de coco,a bacterial cellulose(BC)hydrogel fermented from coconut water or milk,is valued in the global plant-based market for its dietary fiber,zero cholesterol,and low calories.However,its commercial application...Nata de coco,a bacterial cellulose(BC)hydrogel fermented from coconut water or milk,is valued in the global plant-based market for its dietary fiber,zero cholesterol,and low calories.However,its commercial applications are challenged by low yield,high costs,and texture degradation with time.To address this,diammonium phosphate(DAP)is first introduced into the fermentation medium to increase nata de coco yield,and then sodium alginate(SA)treatment is followed to modify its microstructures and textures.Results indicate that DAP not only promotes bacterial growth but also specifically upregulates the activity of UGP,a key enzyme in BC synthesis,thereby increasing nata de coco yield.At the optimal DAP concentration(0.01%,w/w),the weight yield(dry base)of nata de coco is increased by 132.3%,from 6.5 g L^(-1) to 15.1 g L^(-1).Further optimization of SA treatment conditions(1.0%(w/w)SA,75℃ for 6 h)results in enhanced interpenetration between BC and SA networks,achieving desirable modulus,hardness,and chewiness(16.85 kPa,310.73 N,and 6.84 N,respectively).Compared to conventional single-factor regulation methods,this study synergistically achieves efficient nata de coco production and textural modification.展开更多
Low temperature stress causes rapid production of reactive oxygen species(ROS)and ROS-induced oxidative damage in yeast Saccharomyces cerevisiae,while yeast can decrease ROS content in general by enhancing GSH content...Low temperature stress causes rapid production of reactive oxygen species(ROS)and ROS-induced oxidative damage in yeast Saccharomyces cerevisiae,while yeast can decrease ROS content in general by enhancing GSH content and enzymatic activities of antioxidases to protect against oxidative stress.Moreover,NAT1(α-N-acetyltransferase complex A subunit)was identified as the key gene related to enhance tolerance of S.cerevisiae strain ZX11 to low temperature by quantitative trait loci(QTL)analysis.To get insight into the biochemical mechanisms of S.cerevisiae ZX11 tolerance to low temperature,the enhanced GSH biosynthesis,enzymatic activities of antioxidases and NatA were detected when S.cerevisiae ZX11 was treated under 4℃.Furthermore,the N-terminus of Nat1p was confirmed essential for its binding to Ard1p and the key binding sites and the active sites including Arg452,Phe453 of Nat1p and Leu24,Asp26,Tyr28 and Tyr181 of Ard1p were identified via sitedirected/truncated mutagenesis and in vitro enzymatic activity assay.The acetylation of Glr1p(glutathionedisulfide reductase)by NatA complex at low temperatures was also identified via HPLC-MS,which would enhance the protein stability of Glr1p and increase further the conversion of GSSG to GSH.Accompanied with the enhanced antioxidases activity,Nat1p would improve the tolerance of S.cerevisiae ZX11 by increasing GSH content and GSH:GSSG ratio via acetylated Glr1p to protect against oxidative damage induced by low temperature stress.These results provide a great insight into the biochemical mechanisms of S.cerevisiae ZX11 tolerance to low temperature.展开更多
During recovery from heat stress,plants clear away the heat-stress-induced misfolded proteins through the ubiquitin-proteasome system(UPS).In the UPS,the recognition of substrate proteins by E3 ligase can be regulated...During recovery from heat stress,plants clear away the heat-stress-induced misfolded proteins through the ubiquitin-proteasome system(UPS).In the UPS,the recognition of substrate proteins by E3 ligase can be regulated by the N-terminal acetyltransferase A(NatA)complex.Here,we determined that Arabidopsis STRESS-RELATED UBIQUITIN-ASSOCIATED-DOMAIN PROTEIN FACTOR 1(SUF1)interacts with the NatA complex core subunit NAA15 and positively regulates NAA15.The suf1 and naa15 mutants are sensitive to heat stress;the NatA substrate NSNC1 is stabilized in suf1 mutant plants during heat stress recovery.Therefore,SUF1 and its interactor NAA15 play important roles in basal thermotolerance in Arabidopsis.展开更多
椰果(Nata de Coco)是以椰子汁为主要原料,经由醋酸杆菌(Acetobacter)进行生物培养、发酵而成的一种具有独特凝胶结构的细菌纤维素。本文综述了生产过程中影响椰果产率的因素及椰果的物理化学特性、加工特性和功能特性,并提出该产品今...椰果(Nata de Coco)是以椰子汁为主要原料,经由醋酸杆菌(Acetobacter)进行生物培养、发酵而成的一种具有独特凝胶结构的细菌纤维素。本文综述了生产过程中影响椰果产率的因素及椰果的物理化学特性、加工特性和功能特性,并提出该产品今后的发展方向。展开更多
基金supported by the National Natural Science Foundation of China(No.32060529 and 31660458)Innovation Programme for Young Science and Technology Talents of Hainan Science and Technology Association(No.QCQTXM202208)+1 种基金the Key Research and Development Project of Hainan Province(No.ZDYF2020102)the Hainan Graduate Innovation Research Project(No.Qhys2022-194 and Qhyb2021-05).
文摘Nata de coco is a traditional fermented food,chemically known as bacterial cellulose(BC),widely used in the food industry,personal care,and biomaterial areas.In the nata de coco industry,microbiota-fermented coconut water(FCW)has been regarded as a highly efficient medium for improving BC synthesis by Komagataeibacter spp.However,its effects on the biological properties of the strains of Komagataeibacter and structural characteristics of BC remain unknown,resulting in unstable production and BC quality.This study aimed to explore the biological properties of K.nataicola,the characteristics of BC structure and reasons for the efficiency under the effect of FCW.The results showed that FCW could increase the BC yield of K.nataicola by 2.03-4.75 times,the uridine diphosphate glucose pyrophosphorylase activity by 10-45.3 times,and the hexokinase,phosphofructokinase,or pyruvate kinase activities by 2 times.The extracellular metabolite profile of K.nataicola showed that its glycolysis/gluconeogenesis pathway was significantly stimulated and the utilization of erythritol obviously increased.These phenomena might be attributed to the use of ethanol,lactate,xylitoland mannitol in FCW by K.nataicola.In addition,the structural characteristics of BC produced in FCW included higher number of hydrogen bonds,thinner fibrils,a looser three-dimensional network,improved porosity and greater mechanical strength.This study offered novel insights into the BC synthesis of K.nataicola and the BC structural characteristics cultivated in FCW,providing valuable references for the efficient production and potential applications of both nata de coco and BC.
文摘The authors regrets that there were certain errors in the published article which detailed below.Correction to the original text in the Abstract:“The KEGG pathway analysis of differential metabolites showed that the GPb4103 hindered BC synthesis of the JY6211 by altering accu-mulation of metabolites in the fermentation broth through metabolic pathways.”Corrected text is as follows:The KEGG pathway analysis of differential metabolites showed that the GPb4103 hindered BC synthesis of the JY6211 by altering accu-mulation of metabolites in the fermentation broth through BC anabo-lism pathway.
基金financially supported by the Key Technologies Research and Development Program of China(2022YFB3805001)the Excellent Youth Foundation of Jiangsu Scientific Committee(BK20220154)the Fundamental Research Funds for the Central Universities(JUSRP622031).
文摘Nata de coco,a bacterial cellulose(BC)hydrogel fermented from coconut water or milk,is valued in the global plant-based market for its dietary fiber,zero cholesterol,and low calories.However,its commercial applications are challenged by low yield,high costs,and texture degradation with time.To address this,diammonium phosphate(DAP)is first introduced into the fermentation medium to increase nata de coco yield,and then sodium alginate(SA)treatment is followed to modify its microstructures and textures.Results indicate that DAP not only promotes bacterial growth but also specifically upregulates the activity of UGP,a key enzyme in BC synthesis,thereby increasing nata de coco yield.At the optimal DAP concentration(0.01%,w/w),the weight yield(dry base)of nata de coco is increased by 132.3%,from 6.5 g L^(-1) to 15.1 g L^(-1).Further optimization of SA treatment conditions(1.0%(w/w)SA,75℃ for 6 h)results in enhanced interpenetration between BC and SA networks,achieving desirable modulus,hardness,and chewiness(16.85 kPa,310.73 N,and 6.84 N,respectively).Compared to conventional single-factor regulation methods,this study synergistically achieves efficient nata de coco production and textural modification.
基金supported by the National Natural Science Foundation of China(32372312).
文摘Low temperature stress causes rapid production of reactive oxygen species(ROS)and ROS-induced oxidative damage in yeast Saccharomyces cerevisiae,while yeast can decrease ROS content in general by enhancing GSH content and enzymatic activities of antioxidases to protect against oxidative stress.Moreover,NAT1(α-N-acetyltransferase complex A subunit)was identified as the key gene related to enhance tolerance of S.cerevisiae strain ZX11 to low temperature by quantitative trait loci(QTL)analysis.To get insight into the biochemical mechanisms of S.cerevisiae ZX11 tolerance to low temperature,the enhanced GSH biosynthesis,enzymatic activities of antioxidases and NatA were detected when S.cerevisiae ZX11 was treated under 4℃.Furthermore,the N-terminus of Nat1p was confirmed essential for its binding to Ard1p and the key binding sites and the active sites including Arg452,Phe453 of Nat1p and Leu24,Asp26,Tyr28 and Tyr181 of Ard1p were identified via sitedirected/truncated mutagenesis and in vitro enzymatic activity assay.The acetylation of Glr1p(glutathionedisulfide reductase)by NatA complex at low temperatures was also identified via HPLC-MS,which would enhance the protein stability of Glr1p and increase further the conversion of GSSG to GSH.Accompanied with the enhanced antioxidases activity,Nat1p would improve the tolerance of S.cerevisiae ZX11 by increasing GSH content and GSH:GSSG ratio via acetylated Glr1p to protect against oxidative damage induced by low temperature stress.These results provide a great insight into the biochemical mechanisms of S.cerevisiae ZX11 tolerance to low temperature.
基金financially supported by grants from the National Natural Science Foundation of China(Nos 31625004and 31970287)the Zhejiang Provincial Talent Program(No.2019R52005)。
文摘During recovery from heat stress,plants clear away the heat-stress-induced misfolded proteins through the ubiquitin-proteasome system(UPS).In the UPS,the recognition of substrate proteins by E3 ligase can be regulated by the N-terminal acetyltransferase A(NatA)complex.Here,we determined that Arabidopsis STRESS-RELATED UBIQUITIN-ASSOCIATED-DOMAIN PROTEIN FACTOR 1(SUF1)interacts with the NatA complex core subunit NAA15 and positively regulates NAA15.The suf1 and naa15 mutants are sensitive to heat stress;the NatA substrate NSNC1 is stabilized in suf1 mutant plants during heat stress recovery.Therefore,SUF1 and its interactor NAA15 play important roles in basal thermotolerance in Arabidopsis.
