Toxoplasma gondii(T.gondii)is an obligate intracellular parasite with a wide range of hosts,including humans and many warm-blooded animals.The parasite exists in two interconvertible forms,namely tachyzoites and brady...Toxoplasma gondii(T.gondii)is an obligate intracellular parasite with a wide range of hosts,including humans and many warm-blooded animals.The parasite exists in two interconvertible forms,namely tachyzoites and bradyzoites in intermediate hosts that are responsible for acute and chronic infections respectively.Mature bradyzoites accumulate large amounts of amylopectin granules but their roles have not been fully characterized.In this study,the predicted key enzymes involved in amylopectin synthesis(UDP-sugar pyrophospharylase,USP)and degradation(alpha-glucan water dikinase,GWD)of ME49 strain were individually knocked out,and then bradyzoite-related phenotyping experiments in vitro and in vivo were performed to dissect their roles during parasite growth and development.Deletion of the usp or gwd gene in the type II strain ME49 reduced the replication rates of tachyzoites in vitro and parasite virulence in vivo,suggesting that amylopectin metabolism is important for optimal tachyzoite growth.Interestingly,the Δusp mutant grew slightly faster than the parental strain under stress conditions that induced bradyzoite transition,which was likely due to the decreased efficiency of bradyzoite formation of theΔusp mutant.Although theΔgwd mutant could convert to bradyzoite robustly in vitro,it was significantly impaired in establishing chronic infection in vivo.Both the Δusp and Δgwd mutants showed a dramatic reduction in the reactivation of chronic infection in an in vitro model.Together,these results suggest that USP and GWD,which are involved in amylopectin synthesis and degradation have important roles in tachyzoite growth,as well as in the formation and reactivation of bradyzoites in T.gondii.展开更多
[Objective]The aim was to research the effect of fast neutron irradiation on amylose content and amylopectin structure.[Method] The amylose content and amylopectin structure of the M4 plants of Thailand rice cultivar ...[Objective]The aim was to research the effect of fast neutron irradiation on amylose content and amylopectin structure.[Method] The amylose content and amylopectin structure of the M4 plants of Thailand rice cultivar Jao Hom Nin irradiated with fast neutron at 13 Gy were evaluated and analyzed in this paper.[Result]The results showed that amylose content of rice could be changed by fast neutron irradiation,many rice mutants with reduced amylose content and many others with enhanced amylose content even some mutants with amylose content near to waxy rice could be isolated,but fast neutron irradiation almost had no effect on amylopectin structure of the samples.[Conclusion]The study provided a basis for breeding rice cultivar with different amylose content in order to meet with the taste hobby of different people and the further processing of diverse rice products via the irradiation of fast neutron.展开更多
Regenerated cellulose/amylopectin blend fibers with controlled biodegradation were produced using dry-jet wet-spinning technology from cellulose/amylopectin/1-butyl-3-methylimidazolium chloride blends.Morphological,st...Regenerated cellulose/amylopectin blend fibers with controlled biodegradation were produced using dry-jet wet-spinning technology from cellulose/amylopectin/1-butyl-3-methylimidazolium chloride blends.Morphological,structural and chemical analyses revealed that dense,homogeneous and void-free blend fibers were prepared in a two-stage dissolution process.The blend fibers were regenerated from water and treated with water or 95%(volume fraction)ethanol.However,cellulose-amylopectin interactions caused crystalline rearrangements in the blend fibers,resulting in a general decrease in crystallinity.Generally,tensile properties decreased with increasing amylopectin content,except that the blend fibers with 10%(mass fraction)amylopectin exhibited higher tensile strength than the regenerated cellulose control fibers.Ethanol treatment reduced the hydrophilicity of the blend fibers,increasing the crystallinity of the blend fibers.The blend fibers exhibited remarkable degradation,directly proportional to the amylopectin content.Despite higher crystallinity,ethanol-treated blend fibers degraded faster than water-treated fibers,indicating amylopectin and ethanol regulated the degradation.展开更多
Background: Starch is the main source of energy in commonly used pig diets.Besides effects related to the extent of starch digestion,also several effects related to variation in digestion rate have recently been demon...Background: Starch is the main source of energy in commonly used pig diets.Besides effects related to the extent of starch digestion,also several effects related to variation in digestion rate have recently been demonstrated in non-ruminants.Different rates of starch digestion in animals and in in vitro models have been reported,depending on the botanic origin of starch.Starches from different botanic sources differ widely in structural and molecular properties.Predicting the effect of starch properties on in vitro digestion kinetics based on existing literature is hampered by incomplete characterization of the starches,or by a selective choice of starches from a limited number of botanic sources.This research aimed to analyse the relationships between starch properties and in vitro digestion kinetics of pure starches isolated from a broad range of botanic origins,which are used in non-ruminant diets or have a potential to be used in the future.Therefore we studied starch digestion kinetics of potato,pea,corn,rice,barley,and wheat starches,and analysed the granule diameter,number of pores,type and amount of crystalline structure,amylose content and amylopectin side-chain length of all starches.Results: Multivariate analysis revealed strong correlations among starch properties,leading us to conclude that effects of most starch characteristics are strongly interrelated.Across all analysed botanic sources,crystalline type and amylopectin chain length showed the strongest correlation with in vitro digestion kinetics.Increased percentages of A–type crystalline structure and amylopectin side chains of DP 6–24 both increased the rate of digestion.In addition,within,but not across,(clusters of) botanic sources,a decrease in amylose content and increase in number of pores correlated positively with digestion kinetics.Conclusion: The type of crystalline structure and amylopectin chain length distribution of starch correlate significantly with digestion kinetics of starches across botanic sources in an in vitro pig model.Variation in digestion kinetics across botanic sources is not additively explained by other starch properties measured,but appears to be confined within botanical sources.展开更多
Based on known cDNAs of rice starch synthase isoforms,we constructed dsRNA interference vectors for starch synthase I(SSI)to produce transgenic plants containing starch with a moderately high amylose content.We invest...Based on known cDNAs of rice starch synthase isoforms,we constructed dsRNA interference vectors for starch synthase I(SSI)to produce transgenic plants containing starch with a moderately high amylose content.We investigated the effect of SSI suppression on grain quality traits,starch biosynthesis,and amylopectin chain distribution in rice plants exposed to two different temperature regimes.The activities and transcripts of BEs,DBEs,and other SS isoforms were further investigated to clarify the effect of SSI suppression on these key enzymes and their specific isoforms under different temperature treatments.Suppression of SSI by RNAi altered grain starch component and amylopectin chain distribution,but it exerted only a slight effect on total starch content(%)and accumulation amount(mg kernel?1)and on starch granule morphology and particle size distribution.Under normal temperature(NT),insignificant differences in kernel weight,chalky kernel proportion,chalky degree,and starch granule morphology between SSI-RNAi line and its wild type(WT)were observed.However,amylose content(AC)level and granule-bound starch synthase(GBSS)activity in rice endosperms were markedly increased by SSI-RNAi suppression.The chalky kernel proportion and chalky degree of SSIRNAi lines were significantly higher than those of WT under high temperature(HT)exposure at filling stage.Inhibition of SSI by RNAi affected amylopectin chain distribution and raised starch gelatinization temperature(GT)in two ways:directly from the SSI deficiency itself and indirectly by reducing BEIIb amounts in an SSI-deficient background.The deficiency of SSI expression led to an alteration in the susceptibility of grain chalkiness occurrence and starch gelatinization temperature to HT exposure,owing to a pleiotropic effect of SSI deficiency on the expression of other genes associated with starch biosynthesis.展开更多
This study evaluated the effects of the dietary starch amylose/amylopectin ratio on growth performance,rumen fermentation and blood parameters,carcass characteristics and marbling score,and meat fatty acid profiles an...This study evaluated the effects of the dietary starch amylose/amylopectin ratio on growth performance,rumen fermentation and blood parameters,carcass characteristics and marbling score,and meat fatty acid profiles and transcriptional changes in the genes involved in the gluconeogenesis pathway in Chinese Qinchuan cattle.Forty-five cattle were randomly divided into three groups.The bulls were fed a control diet(middle amylose/amylopectin ratio=0.47)or diets with either waxy corn starch(WS)inclusion(low amylose/amylopectin ratio=0.23)or pea starch(PS)inclusion(high amylose/amylopectin ratio=0.60)for 90 days.The bulls were individually allowed to receive the diets at the daily amount of at least 2.1%of their individual BW twice daily.The bulls were weighed at 45-day intervals,and blood and rumen fluid samples were also collected at 45-day intervals.The bulls were slaughtered and longissimus thoracis(LT)samples were collected for meat quality measurements.Compared with PS,the average daily gain(ADG)and feed efficiency in control and WS were increased(P<0.05)during d 0 to 45.However,the feed efficiency in PS was increased(P<0.05)compared with the control and WS during d 46 to 90.During the whole feeding trial,the ADG in control and WS showed trends that were higher(0.05<P<0.1)than that of PS,while other growth performance measures and feed intake did not differ(P>0.05)among the three groups.Compared with PS,the serum insulin concentration in WS was increased(P<0.05)at d 45,but not at d 90.Compared with control and WS,the serum SOD and T-AOC concentrations in PS were increased(P<0.05)at d 45,but not at d 90.Compared with control,the rumen microbial crude protein contents in WS and PS were increased(P<0.05)at d 0,while those of control and WS were higher(P<0.05)than that of PS at d 45,but not at d 90.Compared with PS,the backfat thickness in control and WS were increased(P<0.05),however,the marbling score and expression of genes related to the gluconeogenesis pathway in liver of the three groups did not differ(P>0.05).Chemical and physio-chemical compositions of LT did not differ(P>0.05)among the three groups.In conclusion,diets with low or middle amylose/amylopectin ratios increased the backfat thickness,and tended to improve ADG,but had no effect on other carcass characteristics,fat content in the LT,or the expression of hepatic genes related to the gluconeogenesis pathway in Chinese Qinchuan cattle.展开更多
Silicon(Si)has been investigated as a promising anode material because of its high theoretical capacity(4200 m Ah g^(-1)).However,silicon anode suffers from huge volume changes during repeated charge–discharge cycles...Silicon(Si)has been investigated as a promising anode material because of its high theoretical capacity(4200 m Ah g^(-1)).However,silicon anode suffers from huge volume changes during repeated charge–discharge cycles.In this work,inspired by a remarkable success of the glutinous rice mortar in the Great Wall with ca.2000-year history,amylopectin(AP),the key ingredient responsible for the strong bonding force,is extracted from glutinous rice and utilized as a flexible,aqueous,and resilient binder to address the most challenging drastic volume-expansion and pulverization issues of silicon anode.Additionally,the removal of toxic N-methyl-2-pyrrolidone(NMP)organic solvent makes the electrode fabrication process environmentally friendly and healthy.The as-prepared Si-AP electrode with 60 wt%of Si can uphold a high discharge capacity of 1517.9 m Ah g^(-1)at a rate of 0.1 C after 100 cycles.The cycling stability of the Si-AP has been remarkably improved in comparison with both traditional polyvinylidene fluoride(PVDF)and aqueous carboxymethylcellulose(CMC)binders.Moreover,when the content of silicon in the Si-AP electrode increases to 70 wt%,a high discharge capacity of 1463.1 m Ah g^(-1)can still be obtained after 50 cycles at 0.1°C.These preliminary results suggest that the sustainably available and environmentally benign amylopectin binders could be a promising choice for the construction of highly stable silicon anodes.展开更多
Understanding the molecular factors of rice degradation during its aging concerns our research team. This article emphasizes oryzenin-amylopectin. It aims to reveal the mechanism of amylopectin deterioration during ri...Understanding the molecular factors of rice degradation during its aging concerns our research team. This article emphasizes oryzenin-amylopectin. It aims to reveal the mechanism of amylopectin deterioration during rice aging. The research exploits the Natural Bond Analysis and ONION method at theory level DFT/B3LYP/6-31+G(d, p) and AM1. This methodological approach allows highlighting amylopectin transformation;oryzenin converts amylopectin into amyloidosis in continuous. This led to monosaccharides and disaccharides.展开更多
The research aims to help reduce the enormous post-harvest losses of rice or bananas in Cote d’Ivoire. It focuses on the breakdown mechanism of their starch. This process contributes to their decay. This study wants ...The research aims to help reduce the enormous post-harvest losses of rice or bananas in Cote d’Ivoire. It focuses on the breakdown mechanism of their starch. This process contributes to their decay. This study wants to elucidate it;to do this, it analyzes the tetra or penta saccharide reactions with the water or dioxide carbon. It calculates the geometric, energetic and spectroscopic parameters at the ONIOM level (B3LYP/6-311++G [d, p]: AM1). These quantities allow establishing that oxygen <img src="Edit_7761c26d-f67d-4826-ab0e-8bff55d6faa3.png" alt="" /> represents the privileged hydrogen bond (HB) site for amylose with four or five D-glucose building blocks. They suggest <img src="Edit_ecd55400-653e-43d0-986d-9814259ebda7.png" alt="" /> and <img src="Edit_048b683f-5690-4078-b8ad-88fa25c5875c.png" alt="" /> are respectively those of amylopectin when the latter consists of four and five D-glucose synthons. They prove that amylose deteriorates before it;the degradation of starch begins with its alteration into disaccharides. It continues with that of amylopectin into tri or tetra-saccharides with four or five building blocks.展开更多
The effect of γ irradiation on the cooked rice texture and amylopectin structure is studied with three varieties (Zhefu 504, Zhefu 802 and Zaogeng T2) subjected to 4kGy, skGy and 12kGy irradiation. The results indica...The effect of γ irradiation on the cooked rice texture and amylopectin structure is studied with three varieties (Zhefu 504, Zhefu 802 and Zaogeng T2) subjected to 4kGy, skGy and 12kGy irradiation. The results indicate that irradiation has significant effect on the texture of the cooked rice; the hardness, cohesiveness,gumminess and chewiness reduce significantly with the increase of the irradiation dose.Irradiation also affects the chain length distribution of the amylopectin, the side-chains of amylopectin of Zhefu 504 with the 12DP, Zhefu 802 with 24DP13 and Zaogeng T2 with 24DP13 and 36DP25 are broken.展开更多
The dynamic changes of the activities of enzymes involving in starch biosynthesis, including ADP-glucose pyrophosphorylase (AGPase), soluble starch synthases (SSS), starch branching enzyme (SBE) and starch debranching...The dynamic changes of the activities of enzymes involving in starch biosynthesis, including ADP-glucose pyrophosphorylase (AGPase), soluble starch synthases (SSS), starch branching enzyme (SBE) and starch debranching enzymes (DBE) were studied, and changes of fine structure of amy- lopectin were characterized by isoamylase treatment during rice grain development, using trans anti-waxy gene rice plants. The relationships between the activities of those key enzymes were also analyzed. The amylose synthesis was significantly inhibited in transgenic Wanjing 9522, but the total starch content and final grain weight were less affected as compared with those of non-transgenic Wanjing 9522 rice cultivar. Analyses on the changes of activities of enzymes involving in starch bio- synthesis showed that different enzyme activities were expressed differently during rice endosperm development. Soluble starch synthase is relatively highly expressed in earlier stage of endosperm de- velopment, whilst maximal expression of granule-bound starch synthase (GBSS) occurred in mid-stage of endosperm development. No obvious differences in changes of the activities of AGPase and SBE between two rice cultivars investigated, except the DBEs. Distribution patterns of branches of amy- lopectin changed continually during the development of rice grains and varied between two rice culti- vars. It was suggested that amylopectin synthesis be prior to the synthesis of amylose and different enzymes have different roles in controlling syntheses of branches of amylopectin.展开更多
This study explored the variation of ileal endogenous amino acid(IEAA)losses and its influencing factors in chickens offered nitrogen-free diets(NFD)containing different ratios of amylose to amylopectin(AM/AP).A total...This study explored the variation of ileal endogenous amino acid(IEAA)losses and its influencing factors in chickens offered nitrogen-free diets(NFD)containing different ratios of amylose to amylopectin(AM/AP).A total of 252 broiler chickens at 28 d old were randomly allocated into 7 treatment groups for a 3-d trial.The dietary treatments included a basal diet(control),a NFD containing corn starch(CS),and 5NFD with AM/AP ratios of 0.20,0.40,0.60,0.80,and 1.00,respectively.As the AM/AP ratio increased,the IEAA losses of all AAs,starch digestibility and maltase activity linearly decreased(P<0.05),but the DM digestibility linearly and quadratically decreased(P<0.05).Compared with the control,the NFD increased the number of goblet cells and its regulatory genes mucin-2 and krüppel-like factor 4(KLF-4)while decreasing serum glucagon and thyroxine concentrations,ileal villus height,and crypt depth(P<0.05).Additionally,NFD with lower AM/AP ratios(0.20 and 0.40)decreased the ileal microbiota species richness(P<0.05).In all NFD groups,the number of Proteobacteria increased whereas the abundance of Firmicutes dropped(P<0.05).However,the broilers in the AM/AP 0.60 group were closer to the digestive physiological state of chickens fed the control diet,with no significant change in maltase activity and mucin-2 expression(P<0.05).In conclusion,increasing AM/AP ratio in a NFD decreased the IEAA losses and the apparent ileal digestibility of starch but inevitably resulted in malnutrition and disruption of gut microbiota homeostasis.This study recommends AM/AP in NFD at 0.60 to measure IEAA of broiler chickens.展开更多
Successful gene vectors should be with high transfection efficiency and minimal cytotoxicity. Natural polysaccharides, due to their good biocompatibility and biodegradability, have been widely studied and applied. Amy...Successful gene vectors should be with high transfection efficiency and minimal cytotoxicity. Natural polysaccharides, due to their good biocompatibility and biodegradability, have been widely studied and applied. Amylopectin is one of polysaccharides with dendritic structure and numerous hydroxyl groups that could be used for subsequent modification. In this work, a series of dendritic cationic gene vectors comprising amylopectin backbones and poly(2-(dimethylamino) ethyl methacrylate)(PDMAEMA) side chains with different lengths(termed as AMY-PDs) were readily prepared by atom transfer radical polymerization(ATRP). The gene condensation ability, cytotoxicity and gene transfection of AMY-PDs carriers were investigated. In comparison with "gold-standard" poly(ethyleneimine)(PEI, 25 k Da), the AMY-PDs exhibited higher transfection efficiency with lower cytotoxicity. AMY-PDs could be further modified with Au nanoparticles(termed as AMY-PD@Au). The potential of the AMY-PD@Au vectors to be utilized as a CT contrast agent for imaging of cancer cells was investigated. Such AMY-PD@Au vectors may realize gene therapy with the ability of real-time imaging.展开更多
建立谷子种质资源品质性状的快速、高效检测对挖掘具有优异品质性状的资源具有重要意义。本研究选取来自于国内外不同生态区谷子种质资源657份,采用双波长法测定种子的直链淀粉、支链淀粉和总淀粉含量,在此基础上选择550份种质用Unscram...建立谷子种质资源品质性状的快速、高效检测对挖掘具有优异品质性状的资源具有重要意义。本研究选取来自于国内外不同生态区谷子种质资源657份,采用双波长法测定种子的直链淀粉、支链淀粉和总淀粉含量,在此基础上选择550份种质用Unscrambler X 10.4化学计量软件构建直链淀粉、支链淀粉和总淀粉的近红外模型,利用标准正常化结合散射处理(SNV and Detrend)和一阶导数处理参数对原始光谱进行预处理,用偏最小二乘法(PLS)构建光谱模型。试验结果表明,657份谷子种质的直链淀粉含量为2.99%~22.40%,平均值为16.25%;支链淀粉含量为52.77%~76.09%,平均值为59.56%;总淀粉含量为62.53%~83.31%,平均值为75.81%;直支比为0.04~0.40,平均值为0.28。国外种质的直链淀粉和总淀粉的变异系数最高,分别为30.08%、5.07%;与国内种质相比,国外种质的平均总淀粉含量最低,平均值为75.19%,幅度范围为64.65%~82.38%。国内5个生态区谷子种质的淀粉含量差异明显,内蒙古高原区直链淀粉、总淀粉和直支比的变异系数最高,分别为29.40%、4.07%、30.77%;东北春谷区种质的支链淀粉的变异系数最高,为6.00%;南方谷子栽培区种质的直链淀粉、支链淀粉、总淀粉和直支比的变异系数最低,分别为8.21%、4.40%、2.97%和10.71%。本研究筛选出的高直支比和高支链淀粉含量在前5名的材料均来自于华北夏谷区、黄土高原区和东北春谷区,其中黄土高原区二毛尖的直支比和直链淀粉最高(0.40、22.40%),华北夏谷区半芒红谷的支链淀粉含量最高(76.09%)。直链淀粉、支链淀粉和总淀粉的近红外预测模型校正相关系数(Rcal2)分别为0.910、0.848和0.717,交叉验证决定系数(R_(cv)^(2))分别为0.902、0.830和0.675,外部验证决定系数(R_(val)^(2))分别为0.903、0.826和0.702,定标标准误差(SEC)分别为1.156、1.234和1.367,交叉检验标准误差(RMSECV)分别为1.208、1.288和1.471,验证标准偏差(RMSEP)分别为1.130、1.260和1.649,外部验证相对分析误差(RPD)分别为3.415、2.539和1.765,最佳因子分别为9、10、10。研究表明,国内外不同生态区的谷子种质在淀粉含量上呈显著多样性,且本研究开发的近红外光谱(NIRS)模型可用于预测谷子的直链淀粉和支链淀粉含量,总淀粉含量虽然可以粗略预测,但仍需进一步的调整和优化以提高准确性。展开更多
基金supported by the Fundamental Research Funds for the Central Universities in China(Grant no.2662022DKPY003)the HZAU-AGIS Cooperation Fund(Grant no.SZYJY2022015).
文摘Toxoplasma gondii(T.gondii)is an obligate intracellular parasite with a wide range of hosts,including humans and many warm-blooded animals.The parasite exists in two interconvertible forms,namely tachyzoites and bradyzoites in intermediate hosts that are responsible for acute and chronic infections respectively.Mature bradyzoites accumulate large amounts of amylopectin granules but their roles have not been fully characterized.In this study,the predicted key enzymes involved in amylopectin synthesis(UDP-sugar pyrophospharylase,USP)and degradation(alpha-glucan water dikinase,GWD)of ME49 strain were individually knocked out,and then bradyzoite-related phenotyping experiments in vitro and in vivo were performed to dissect their roles during parasite growth and development.Deletion of the usp or gwd gene in the type II strain ME49 reduced the replication rates of tachyzoites in vitro and parasite virulence in vivo,suggesting that amylopectin metabolism is important for optimal tachyzoite growth.Interestingly,the Δusp mutant grew slightly faster than the parental strain under stress conditions that induced bradyzoite transition,which was likely due to the decreased efficiency of bradyzoite formation of theΔusp mutant.Although theΔgwd mutant could convert to bradyzoite robustly in vitro,it was significantly impaired in establishing chronic infection in vivo.Both the Δusp and Δgwd mutants showed a dramatic reduction in the reactivation of chronic infection in an in vitro model.Together,these results suggest that USP and GWD,which are involved in amylopectin synthesis and degradation have important roles in tachyzoite growth,as well as in the formation and reactivation of bradyzoites in T.gondii.
基金Supported by Tingthanathikul Foundation Agricultural Fellowship in Thailand for Study and Intercommunion in 2009~~
文摘[Objective]The aim was to research the effect of fast neutron irradiation on amylose content and amylopectin structure.[Method] The amylose content and amylopectin structure of the M4 plants of Thailand rice cultivar Jao Hom Nin irradiated with fast neutron at 13 Gy were evaluated and analyzed in this paper.[Result]The results showed that amylose content of rice could be changed by fast neutron irradiation,many rice mutants with reduced amylose content and many others with enhanced amylose content even some mutants with amylose content near to waxy rice could be isolated,but fast neutron irradiation almost had no effect on amylopectin structure of the samples.[Conclusion]The study provided a basis for breeding rice cultivar with different amylose content in order to meet with the taste hobby of different people and the further processing of diverse rice products via the irradiation of fast neutron.
文摘Regenerated cellulose/amylopectin blend fibers with controlled biodegradation were produced using dry-jet wet-spinning technology from cellulose/amylopectin/1-butyl-3-methylimidazolium chloride blends.Morphological,structural and chemical analyses revealed that dense,homogeneous and void-free blend fibers were prepared in a two-stage dissolution process.The blend fibers were regenerated from water and treated with water or 95%(volume fraction)ethanol.However,cellulose-amylopectin interactions caused crystalline rearrangements in the blend fibers,resulting in a general decrease in crystallinity.Generally,tensile properties decreased with increasing amylopectin content,except that the blend fibers with 10%(mass fraction)amylopectin exhibited higher tensile strength than the regenerated cellulose control fibers.Ethanol treatment reduced the hydrophilicity of the blend fibers,increasing the crystallinity of the blend fibers.The blend fibers exhibited remarkable degradation,directly proportional to the amylopectin content.Despite higher crystallinity,ethanol-treated blend fibers degraded faster than water-treated fibers,indicating amylopectin and ethanol regulated the degradation.
基金financed by the Topsector Agri&Food and Agrifirm as coordinated by the Dutch Carbohydrate Competence Centre(CCC-ABCwww.cccresearch.nl)
文摘Background: Starch is the main source of energy in commonly used pig diets.Besides effects related to the extent of starch digestion,also several effects related to variation in digestion rate have recently been demonstrated in non-ruminants.Different rates of starch digestion in animals and in in vitro models have been reported,depending on the botanic origin of starch.Starches from different botanic sources differ widely in structural and molecular properties.Predicting the effect of starch properties on in vitro digestion kinetics based on existing literature is hampered by incomplete characterization of the starches,or by a selective choice of starches from a limited number of botanic sources.This research aimed to analyse the relationships between starch properties and in vitro digestion kinetics of pure starches isolated from a broad range of botanic origins,which are used in non-ruminant diets or have a potential to be used in the future.Therefore we studied starch digestion kinetics of potato,pea,corn,rice,barley,and wheat starches,and analysed the granule diameter,number of pores,type and amount of crystalline structure,amylose content and amylopectin side-chain length of all starches.Results: Multivariate analysis revealed strong correlations among starch properties,leading us to conclude that effects of most starch characteristics are strongly interrelated.Across all analysed botanic sources,crystalline type and amylopectin chain length showed the strongest correlation with in vitro digestion kinetics.Increased percentages of A–type crystalline structure and amylopectin side chains of DP 6–24 both increased the rate of digestion.In addition,within,but not across,(clusters of) botanic sources,a decrease in amylose content and increase in number of pores correlated positively with digestion kinetics.Conclusion: The type of crystalline structure and amylopectin chain length distribution of starch correlate significantly with digestion kinetics of starches across botanic sources in an in vitro pig model.Variation in digestion kinetics across botanic sources is not additively explained by other starch properties measured,but appears to be confined within botanical sources.
基金the National Key Research and Development Program of China (2017YFD0300103)the National Natural Science Foundation of China (31571602, 31871566) for its financial support to this research project
文摘Based on known cDNAs of rice starch synthase isoforms,we constructed dsRNA interference vectors for starch synthase I(SSI)to produce transgenic plants containing starch with a moderately high amylose content.We investigated the effect of SSI suppression on grain quality traits,starch biosynthesis,and amylopectin chain distribution in rice plants exposed to two different temperature regimes.The activities and transcripts of BEs,DBEs,and other SS isoforms were further investigated to clarify the effect of SSI suppression on these key enzymes and their specific isoforms under different temperature treatments.Suppression of SSI by RNAi altered grain starch component and amylopectin chain distribution,but it exerted only a slight effect on total starch content(%)and accumulation amount(mg kernel?1)and on starch granule morphology and particle size distribution.Under normal temperature(NT),insignificant differences in kernel weight,chalky kernel proportion,chalky degree,and starch granule morphology between SSI-RNAi line and its wild type(WT)were observed.However,amylose content(AC)level and granule-bound starch synthase(GBSS)activity in rice endosperms were markedly increased by SSI-RNAi suppression.The chalky kernel proportion and chalky degree of SSIRNAi lines were significantly higher than those of WT under high temperature(HT)exposure at filling stage.Inhibition of SSI by RNAi affected amylopectin chain distribution and raised starch gelatinization temperature(GT)in two ways:directly from the SSI deficiency itself and indirectly by reducing BEIIb amounts in an SSI-deficient background.The deficiency of SSI expression led to an alteration in the susceptibility of grain chalkiness occurrence and starch gelatinization temperature to HT exposure,owing to a pleiotropic effect of SSI deficiency on the expression of other genes associated with starch biosynthesis.
基金the major Scientific and Technological Projects of Ningxia(2018GYYQ0002,China)the Beijing Natural Science Foundation(6194042)+1 种基金the Earmarked Fund for the Beijing Dairy Industry Innovation Consortium of the Agriculture Research System(BAIC06-2020,China)the Agricultural Science and Technology Innovation Program(CAAS-ASTIP-2017-FRI-04,China).
文摘This study evaluated the effects of the dietary starch amylose/amylopectin ratio on growth performance,rumen fermentation and blood parameters,carcass characteristics and marbling score,and meat fatty acid profiles and transcriptional changes in the genes involved in the gluconeogenesis pathway in Chinese Qinchuan cattle.Forty-five cattle were randomly divided into three groups.The bulls were fed a control diet(middle amylose/amylopectin ratio=0.47)or diets with either waxy corn starch(WS)inclusion(low amylose/amylopectin ratio=0.23)or pea starch(PS)inclusion(high amylose/amylopectin ratio=0.60)for 90 days.The bulls were individually allowed to receive the diets at the daily amount of at least 2.1%of their individual BW twice daily.The bulls were weighed at 45-day intervals,and blood and rumen fluid samples were also collected at 45-day intervals.The bulls were slaughtered and longissimus thoracis(LT)samples were collected for meat quality measurements.Compared with PS,the average daily gain(ADG)and feed efficiency in control and WS were increased(P<0.05)during d 0 to 45.However,the feed efficiency in PS was increased(P<0.05)compared with the control and WS during d 46 to 90.During the whole feeding trial,the ADG in control and WS showed trends that were higher(0.05<P<0.1)than that of PS,while other growth performance measures and feed intake did not differ(P>0.05)among the three groups.Compared with PS,the serum insulin concentration in WS was increased(P<0.05)at d 45,but not at d 90.Compared with control and WS,the serum SOD and T-AOC concentrations in PS were increased(P<0.05)at d 45,but not at d 90.Compared with control,the rumen microbial crude protein contents in WS and PS were increased(P<0.05)at d 0,while those of control and WS were higher(P<0.05)than that of PS at d 45,but not at d 90.Compared with PS,the backfat thickness in control and WS were increased(P<0.05),however,the marbling score and expression of genes related to the gluconeogenesis pathway in liver of the three groups did not differ(P>0.05).Chemical and physio-chemical compositions of LT did not differ(P>0.05)among the three groups.In conclusion,diets with low or middle amylose/amylopectin ratios increased the backfat thickness,and tended to improve ADG,but had no effect on other carcass characteristics,fat content in the LT,or the expression of hepatic genes related to the gluconeogenesis pathway in Chinese Qinchuan cattle.
基金financial support from the Australia Research Council Discovery Projects(DP160102627 and DP1701048343)of Australiathe 111 Project(D20015)of China Three Gorges University
文摘Silicon(Si)has been investigated as a promising anode material because of its high theoretical capacity(4200 m Ah g^(-1)).However,silicon anode suffers from huge volume changes during repeated charge–discharge cycles.In this work,inspired by a remarkable success of the glutinous rice mortar in the Great Wall with ca.2000-year history,amylopectin(AP),the key ingredient responsible for the strong bonding force,is extracted from glutinous rice and utilized as a flexible,aqueous,and resilient binder to address the most challenging drastic volume-expansion and pulverization issues of silicon anode.Additionally,the removal of toxic N-methyl-2-pyrrolidone(NMP)organic solvent makes the electrode fabrication process environmentally friendly and healthy.The as-prepared Si-AP electrode with 60 wt%of Si can uphold a high discharge capacity of 1517.9 m Ah g^(-1)at a rate of 0.1 C after 100 cycles.The cycling stability of the Si-AP has been remarkably improved in comparison with both traditional polyvinylidene fluoride(PVDF)and aqueous carboxymethylcellulose(CMC)binders.Moreover,when the content of silicon in the Si-AP electrode increases to 70 wt%,a high discharge capacity of 1463.1 m Ah g^(-1)can still be obtained after 50 cycles at 0.1°C.These preliminary results suggest that the sustainably available and environmentally benign amylopectin binders could be a promising choice for the construction of highly stable silicon anodes.
文摘Understanding the molecular factors of rice degradation during its aging concerns our research team. This article emphasizes oryzenin-amylopectin. It aims to reveal the mechanism of amylopectin deterioration during rice aging. The research exploits the Natural Bond Analysis and ONION method at theory level DFT/B3LYP/6-31+G(d, p) and AM1. This methodological approach allows highlighting amylopectin transformation;oryzenin converts amylopectin into amyloidosis in continuous. This led to monosaccharides and disaccharides.
文摘The research aims to help reduce the enormous post-harvest losses of rice or bananas in Cote d’Ivoire. It focuses on the breakdown mechanism of their starch. This process contributes to their decay. This study wants to elucidate it;to do this, it analyzes the tetra or penta saccharide reactions with the water or dioxide carbon. It calculates the geometric, energetic and spectroscopic parameters at the ONIOM level (B3LYP/6-311++G [d, p]: AM1). These quantities allow establishing that oxygen <img src="Edit_7761c26d-f67d-4826-ab0e-8bff55d6faa3.png" alt="" /> represents the privileged hydrogen bond (HB) site for amylose with four or five D-glucose building blocks. They suggest <img src="Edit_ecd55400-653e-43d0-986d-9814259ebda7.png" alt="" /> and <img src="Edit_048b683f-5690-4078-b8ad-88fa25c5875c.png" alt="" /> are respectively those of amylopectin when the latter consists of four and five D-glucose synthons. They prove that amylose deteriorates before it;the degradation of starch begins with its alteration into disaccharides. It continues with that of amylopectin into tri or tetra-saccharides with four or five building blocks.
文摘The effect of γ irradiation on the cooked rice texture and amylopectin structure is studied with three varieties (Zhefu 504, Zhefu 802 and Zaogeng T2) subjected to 4kGy, skGy and 12kGy irradiation. The results indicate that irradiation has significant effect on the texture of the cooked rice; the hardness, cohesiveness,gumminess and chewiness reduce significantly with the increase of the irradiation dose.Irradiation also affects the chain length distribution of the amylopectin, the side-chains of amylopectin of Zhefu 504 with the 12DP, Zhefu 802 with 24DP13 and Zaogeng T2 with 24DP13 and 36DP25 are broken.
基金the National Key Research and Development Program of China(GrantNo.G199810100)
文摘The dynamic changes of the activities of enzymes involving in starch biosynthesis, including ADP-glucose pyrophosphorylase (AGPase), soluble starch synthases (SSS), starch branching enzyme (SBE) and starch debranching enzymes (DBE) were studied, and changes of fine structure of amy- lopectin were characterized by isoamylase treatment during rice grain development, using trans anti-waxy gene rice plants. The relationships between the activities of those key enzymes were also analyzed. The amylose synthesis was significantly inhibited in transgenic Wanjing 9522, but the total starch content and final grain weight were less affected as compared with those of non-transgenic Wanjing 9522 rice cultivar. Analyses on the changes of activities of enzymes involving in starch bio- synthesis showed that different enzyme activities were expressed differently during rice endosperm development. Soluble starch synthase is relatively highly expressed in earlier stage of endosperm de- velopment, whilst maximal expression of granule-bound starch synthase (GBSS) occurred in mid-stage of endosperm development. No obvious differences in changes of the activities of AGPase and SBE between two rice cultivars investigated, except the DBEs. Distribution patterns of branches of amy- lopectin changed continually during the development of rice grains and varied between two rice culti- vars. It was suggested that amylopectin synthesis be prior to the synthesis of amylose and different enzymes have different roles in controlling syntheses of branches of amylopectin.
基金supported by the National Natural Science Foundation of China(No.31772620)。
文摘This study explored the variation of ileal endogenous amino acid(IEAA)losses and its influencing factors in chickens offered nitrogen-free diets(NFD)containing different ratios of amylose to amylopectin(AM/AP).A total of 252 broiler chickens at 28 d old were randomly allocated into 7 treatment groups for a 3-d trial.The dietary treatments included a basal diet(control),a NFD containing corn starch(CS),and 5NFD with AM/AP ratios of 0.20,0.40,0.60,0.80,and 1.00,respectively.As the AM/AP ratio increased,the IEAA losses of all AAs,starch digestibility and maltase activity linearly decreased(P<0.05),but the DM digestibility linearly and quadratically decreased(P<0.05).Compared with the control,the NFD increased the number of goblet cells and its regulatory genes mucin-2 and krüppel-like factor 4(KLF-4)while decreasing serum glucagon and thyroxine concentrations,ileal villus height,and crypt depth(P<0.05).Additionally,NFD with lower AM/AP ratios(0.20 and 0.40)decreased the ileal microbiota species richness(P<0.05).In all NFD groups,the number of Proteobacteria increased whereas the abundance of Firmicutes dropped(P<0.05).However,the broilers in the AM/AP 0.60 group were closer to the digestive physiological state of chickens fed the control diet,with no significant change in maltase activity and mucin-2 expression(P<0.05).In conclusion,increasing AM/AP ratio in a NFD decreased the IEAA losses and the apparent ileal digestibility of starch but inevitably resulted in malnutrition and disruption of gut microbiota homeostasis.This study recommends AM/AP in NFD at 0.60 to measure IEAA of broiler chickens.
基金supported by the National Natural Science Foundation of China(51173014,51221002,51325304,51373017,51302009,51473014)the Research Fund for Doctoral Program of Higher Education of China(20120010120007)Collaborative Innovation Center for Cardiovascular Disorders,Beijing Anzhen Hospital Affiliated to the Capital Medical University
文摘Successful gene vectors should be with high transfection efficiency and minimal cytotoxicity. Natural polysaccharides, due to their good biocompatibility and biodegradability, have been widely studied and applied. Amylopectin is one of polysaccharides with dendritic structure and numerous hydroxyl groups that could be used for subsequent modification. In this work, a series of dendritic cationic gene vectors comprising amylopectin backbones and poly(2-(dimethylamino) ethyl methacrylate)(PDMAEMA) side chains with different lengths(termed as AMY-PDs) were readily prepared by atom transfer radical polymerization(ATRP). The gene condensation ability, cytotoxicity and gene transfection of AMY-PDs carriers were investigated. In comparison with "gold-standard" poly(ethyleneimine)(PEI, 25 k Da), the AMY-PDs exhibited higher transfection efficiency with lower cytotoxicity. AMY-PDs could be further modified with Au nanoparticles(termed as AMY-PD@Au). The potential of the AMY-PD@Au vectors to be utilized as a CT contrast agent for imaging of cancer cells was investigated. Such AMY-PD@Au vectors may realize gene therapy with the ability of real-time imaging.
文摘建立谷子种质资源品质性状的快速、高效检测对挖掘具有优异品质性状的资源具有重要意义。本研究选取来自于国内外不同生态区谷子种质资源657份,采用双波长法测定种子的直链淀粉、支链淀粉和总淀粉含量,在此基础上选择550份种质用Unscrambler X 10.4化学计量软件构建直链淀粉、支链淀粉和总淀粉的近红外模型,利用标准正常化结合散射处理(SNV and Detrend)和一阶导数处理参数对原始光谱进行预处理,用偏最小二乘法(PLS)构建光谱模型。试验结果表明,657份谷子种质的直链淀粉含量为2.99%~22.40%,平均值为16.25%;支链淀粉含量为52.77%~76.09%,平均值为59.56%;总淀粉含量为62.53%~83.31%,平均值为75.81%;直支比为0.04~0.40,平均值为0.28。国外种质的直链淀粉和总淀粉的变异系数最高,分别为30.08%、5.07%;与国内种质相比,国外种质的平均总淀粉含量最低,平均值为75.19%,幅度范围为64.65%~82.38%。国内5个生态区谷子种质的淀粉含量差异明显,内蒙古高原区直链淀粉、总淀粉和直支比的变异系数最高,分别为29.40%、4.07%、30.77%;东北春谷区种质的支链淀粉的变异系数最高,为6.00%;南方谷子栽培区种质的直链淀粉、支链淀粉、总淀粉和直支比的变异系数最低,分别为8.21%、4.40%、2.97%和10.71%。本研究筛选出的高直支比和高支链淀粉含量在前5名的材料均来自于华北夏谷区、黄土高原区和东北春谷区,其中黄土高原区二毛尖的直支比和直链淀粉最高(0.40、22.40%),华北夏谷区半芒红谷的支链淀粉含量最高(76.09%)。直链淀粉、支链淀粉和总淀粉的近红外预测模型校正相关系数(Rcal2)分别为0.910、0.848和0.717,交叉验证决定系数(R_(cv)^(2))分别为0.902、0.830和0.675,外部验证决定系数(R_(val)^(2))分别为0.903、0.826和0.702,定标标准误差(SEC)分别为1.156、1.234和1.367,交叉检验标准误差(RMSECV)分别为1.208、1.288和1.471,验证标准偏差(RMSEP)分别为1.130、1.260和1.649,外部验证相对分析误差(RPD)分别为3.415、2.539和1.765,最佳因子分别为9、10、10。研究表明,国内外不同生态区的谷子种质在淀粉含量上呈显著多样性,且本研究开发的近红外光谱(NIRS)模型可用于预测谷子的直链淀粉和支链淀粉含量,总淀粉含量虽然可以粗略预测,但仍需进一步的调整和优化以提高准确性。
