期刊文献+
共找到62,493篇文章
< 1 2 250 >
每页显示 20 50 100
Engineering high amylose and resistant starch in maize by CRISPR/Cas9-mediated editing of starch branching enzymes 被引量:1
1
作者 Mingzheng Ma Shanqiu Sun +5 位作者 Jinjie Zhu Xiantao Qi Gaoke Li Jianguang Hu Chuanxiao Xie Changlin Liu 《The Crop Journal》 SCIE CSCD 2024年第4期1252-1258,共7页
To improve the amylose content(AC)and resistant starch content(RSC)of maize kernel starch,we employed the CRISPR/Cas9 system to create mutants of starch branching enzyme I(SBEI)and starch branching enzyme IIb(SBEIIb).... To improve the amylose content(AC)and resistant starch content(RSC)of maize kernel starch,we employed the CRISPR/Cas9 system to create mutants of starch branching enzyme I(SBEI)and starch branching enzyme IIb(SBEIIb).A frameshift mutation in SBEI(E1,a nucleotide insertion in exon 6)led to plants with higher RSC(1.07%),lower hundred-kernel weight(HKW,24.71±0.14 g),and lower plant height(PH,218.50±9.42 cm)compared to the wild type(WT).Like the WT,E1 kernel starch had irregular,polygonal shapes with sharp edges.A frameshift mutation in SBEIIb(E2,a four-nucleotide deletion in exon 8)led to higher AC(53.48%)and higher RSC(26.93%)than that for the WT.E2 kernel starch was significantly different from the WT regarding granule morphology,chain length distribution pattern,X-ray diffraction pattern,and thermal characteristics;the starch granules were more irregular in shape and comprised typical B-type crystals.Mutating SBEI and SBEIIb(E12)had a synergistic effect on RSC,HKW,PH,starch properties,and starch biosynthesis-associated gene expression.SBEIIa,SS1,SSIIa,SSIIIa,and SSIIIb were upregulated in E12 endosperm compared to WT endosperm.This study lays the foundation for rapidly improving the starch properties of elite maize lines. 展开更多
关键词 MAIZE Gene editing Starch branching enzyme I Starch branching enzyme IIb
下载PDF
Timosaponin AⅢ induces drug-metabolizing enzymes by activating constitutive androstane receptor (CAR) via dephosphorylation of the EGFR signaling pathway 被引量:1
2
作者 Muhammad Zubair Hafiz Jie Pan +4 位作者 Zhiwei Gao Ying Huo Haobin Wang Wei Liu Jian Yang 《Journal of Biomedical Research》 CAS CSCD 2024年第4期382-396,共15页
The current study aimed to assess the effect of timosaponin AⅢ(T-AⅢ)on drug-metabolizing enzymes during anticancer therapy.The in vivo experiments were conducted on nude and ICR mice.Following a 24-day administratio... The current study aimed to assess the effect of timosaponin AⅢ(T-AⅢ)on drug-metabolizing enzymes during anticancer therapy.The in vivo experiments were conducted on nude and ICR mice.Following a 24-day administration of T-AⅢ,the nude mice exhibited an induction of CYP2B10,MDR1,and CYP3A11 expression in the liver tissues.In the ICR mice,the expression levels of CYP2B10 and MDR1 increased after a three-day T-AⅢ administration.The in vitro assessments with HepG2 cells revealed that T-AⅢ induced the expression of CYP2B6,MDR1,and CYP3A4,along with constitutive androstane receptor(CAR)activation.Treatment with CAR siRNA reversed the T-AⅢ-induced increases in CYP2B6 and CYP3A4 expression.Furthermore,other CAR target genes also showed a significant increase in the expression.The up-regulation of murine CAR was observed in the liver tissues of both nude and ICR mice.Subsequent findings demonstrated that T-AⅢ activated CAR by inhibiting ERK1/2 phosphorylation,with this effect being partially reversed by the ERK activator t-BHQ.Inhibition of the ERK1/2 signaling pathway was also observed in vivo.Additionally,T-AⅢ inhibited the phosphorylation of EGFR at Tyr1173 and Tyr845,and suppressed EGF-induced phosphorylation of EGFR,ERK,and CAR.In the nude mice,T-AⅢ also inhibited EGFR phosphorylation.These results collectively indicate that T-AⅢ is a novel CAR activator through inhibition of the EGFR pathway. 展开更多
关键词 timosaponin AⅢ CAR metabolism enzyme ERK1/2 signaling pathway EGFR signaling pathway
下载PDF
Identification of key enzymes in lignocellulose biosynthesis from dynamic observations in maize stalks
3
作者 Xiaoxu Zhan Fanlei Kong +6 位作者 Qinlin Liu Tianqiong Lan Fan Liu Xinglong Wang Xia Du Xiang Chen Jichao Yuan 《The Crop Journal》 SCIE CSCD 2024年第6期1754-1764,共11页
Maize stalk lignin and cellulose contents are linked to lodging resistance,disease resistance,feed quality and ethanol conversion efficiency.After the six-leaf stage of maize(V6),these constituents are biosynthesized ... Maize stalk lignin and cellulose contents are linked to lodging resistance,disease resistance,feed quality and ethanol conversion efficiency.After the six-leaf stage of maize(V6),these constituents are biosynthesized and accumulated under the control of related enzymes and genes.However,the key enzymes,critical MYB transcription factors,and their dynamic alterations pattern under natural field circumstances are still unknown.Hence,we selected five cultivars with significant differences in lignocellulose content and lodging resistance as testing materials,performed field experiments for two years,and investigated the dynamics of lignin and cellulose content,related enzyme concentrations,and gene expression levels in the 3^(rd) and 5^(th) internodes above the ground after V6.The results showed that lignin and cellulose content increased after V6,stabilizing during the silking stage.This study identified COMT(caffeic acid 3-Omethyltransferase),TAL(tyrosine ammonia-lyase)and PAL(phenylalanine ammonia-lyase)as the key enzymes of lignin biosynthesis,while ZmCOMT,ZmCesA10 and ZmCesA8 were identified as essential genes.ZmMYB8,ZmMYB31 and ZmMYB39 were involved in regulating the expression of genes related to lignin synthesis,with ZmMYB31 potentially acting as a key negative regulator,while ZmMYB39 and ZmMYB8 acting as positive regulators.The study also found that around 14 d after V6 was a critical stage for regulating lignocellulose synthesis in the 3^(rd) to 5^(th) basal internode.This provides a theoretical foundation for developing regulatory techniques and breeding new cultivars to enhance lodging and disease resistance as well as the utility of maize stalks. 展开更多
关键词 LIGNIN CELLULOSE BIOSYNTHESIS Key enzyme Maize stalk
下载PDF
The Effect of Soil Enzymes and Polysaccharides Secreted by the Roots of Salvia miltiorrhiza Bunge under Drought,High Temperature,and Nitrogen and Phosphorus Deficits
4
作者 Yong Qin Xiaoyu Li +3 位作者 Yanhong Wu Hai Wang Guiqi Han Zhuyun Yan 《Phyton-International Journal of Experimental Botany》 SCIE 2024年第1期119-135,共17页
Root exudates serve as crucial mediators for information exchange between plants and soil,and are an important evolutionary mechanism for plants’adaptation to environmental changes.In this study,15 different abiotic ... Root exudates serve as crucial mediators for information exchange between plants and soil,and are an important evolutionary mechanism for plants’adaptation to environmental changes.In this study,15 different abiotic stress models were established using various stress factors,including drought(D),high temperature(T),nitrogen deficiency(N),phosphorus deficiency(P),and their combinations.We investigated their effects on the seedling growth of Salvia miltiorrhiza Bunge and the activities of Solid-Urease(S-UE),Solid-Nitrite Reductase(S-NiR),Solid-Nitrate Reductase(S-NR),Solid-Phosphotransferase(S-PT),and Solid-Catalase(S-CAT),as well as the contents of polysaccharides in the culture medium.The results showed that the growth of S.miltiorrhiza was inhibited under 15 stress conditions.Among them,13 stress conditions increased the root-shoot ratio.These 15 stress conditions significantly reduced the activity of S-NR,two combinations significantly improved the activity of S-NIR,they were synergistic stresses of high temperature and nitrogen deficiency(TN),and synergistic stresses of drought and nitrogen deficiency(DN)(p<0.05).The activity of S-UE was significantly improved under N,D,T,synergistic stresses of drought and high temperature(DT),DN,synergistic stresses of drought and phosphorus deficiency(DP),and synergistic stresses of high temperature,nitrogen,and phosphorus deficiency(TNP)stress conditions(p<0.05).Most stress combinations reduced the activity of S-PT,but D and T significantly improved it.(p<0.05).The N,DN,and TN stress conditions significantly reduced S-CAT activity.The P,DT,and synergistic stresses of drought,high temperature,and phosphorus deficiency(DTP)significantly decreased the total polysaccharide content of the soil(p<0.05).The research suggested that abiotic stress hindered the growth of S.miltiorrhiza and altered the behavior of root secretion.Roots regulated the secretion of several substances in response to various abiotic stresses,including soil nitrogen cycle enzymes,phosphorus transport-related enzymes,and antioxidant enzymes.In conclusion,plants regulate the utilization of rhizosphere substances in response to abiotic stresses by modulating the exudation of soil enzymes and polysaccharides by the root system.At the same time,soil carbon sequestration was affected by the adverse environment,which restricted the input of organic matter into the soil. 展开更多
关键词 Abiotic stress Salvia miltiorrhiza soil enzymes total polysaccharides soil carbon sequestration
下载PDF
Screening for metabolic dysfunction-associated fatty liver disease:Time to discard the emperor’s clothes of normal liver enzymes?
5
作者 Chen-Xiao Huang Xiao-Dong Zhou +1 位作者 Calvin Q Pan Ming-Hua Zheng 《World Journal of Gastroenterology》 SCIE CAS 2024年第22期2839-2842,共4页
Metabolic dysfunction-associated fatty liver disease(MAFLD)is the most prevalent chronic liver condition worldwide.Current liver enzyme-based screening methods have limitations that may missed diagnoses and treatment ... Metabolic dysfunction-associated fatty liver disease(MAFLD)is the most prevalent chronic liver condition worldwide.Current liver enzyme-based screening methods have limitations that may missed diagnoses and treatment delays.Regarding Chen et al,the risk of developing MAFLD remains elevated even when alanine aminotransferase levels fall within the normal range.Therefore,there is an urgent need for advanced diagnostic techniques and updated algorithms to enhance the accuracy of MAFLD diagnosis and enable early intervention.This paper proposes two potential screening methods for identifying individuals who may be at risk of developing MAFLD:Lowering these thresholds and promoting the use of noninvasive liver fibrosis scores. 展开更多
关键词 Metabolic dysfunction-associated fatty liver disease Non-alcoholic fatty liver disease Alanine aminotransferase Liver enzymes SCREENING Noninvasive liver fibrosis scores
下载PDF
Expression level of myocardial enzymes in patients with schizophrenia: Predictive value in the occurrence of violence
6
作者 Wei-Min He Xin-Yuan Zhang +2 位作者 Wei-Gen Xie Dan-Ping Lv Qun-Di Shen 《World Journal of Psychiatry》 SCIE 2024年第9期1346-1353,共8页
BACKGROUND Schizophrenic patients are prone to violence,frequent recurrence,and difficult to predict.Emotional and behavioral abnormalities during the onset of the disease,resulting in active myocardial enzyme spectru... BACKGROUND Schizophrenic patients are prone to violence,frequent recurrence,and difficult to predict.Emotional and behavioral abnormalities during the onset of the disease,resulting in active myocardial enzyme spectrum.AIM To explored the expression level of myocardial enzymes in patients with schizo-phrenia and its predictive value in the occurrence of violence.METHODS A total of 288 patients with schizophrenia in our hospital from February 2023 to January 2024 were selected as the research object,and 100 healthy people were selected as the control group.Participants’information,clinical data,and labo-ratory examination data were collected.According to Modified Overt Aggression Scale score,patients were further divided into the violent(123 cases)and non-violent group(165 cases).RESULTS The comparative analysis revealed significant differences in serum myocardial enzyme levels between patients with schizophrenia and healthy individuals.In the schizophrenia group,the violent and non-violent groups also exhibited different levels of serum myocardial enzymes.The levels of myocardial enzymes in the non-violent group were lower than those in the violent group,and the patients in the latter also displayed aggressive behavior in the past.CONCLUSION Previous aggressive behavior and the level of myocardial enzymes are of great significance for the diagnosis and prognosis analysis of violent behavior in patients with schizophrenia.By detecting changes in these indicators,we can gain a more comprehensive understanding of a patient’s condition and treatment. 展开更多
关键词 SCHIZOPHRENIA Myocardial enzyme index Act of violence PREDICT Violence prediction Aggressive behavior Clinical data analysis Biochemical markers
下载PDF
西北绿洲灌区玉米叶片衰老特征对不同地膜覆盖利用方式的响应
7
作者 王丽萍 李盼 +6 位作者 赵连豪 樊志龙 胡发龙 范虹 何蔚 柴强 殷文 《作物学报》 CAS 北大核心 2025年第1期233-246,共14页
西北绿洲灌区玉米传统生产模式中大量使用地膜伴随着生态环境污染严重,且在极端高温下玉米出现叶片早衰。针对该现象,通过免耕一膜2年覆盖利用技术探讨延缓玉米叶片衰老并增加玉米产量的可行性,以期为构建西北绿洲灌区地膜减量玉米高效... 西北绿洲灌区玉米传统生产模式中大量使用地膜伴随着生态环境污染严重,且在极端高温下玉米出现叶片早衰。针对该现象,通过免耕一膜2年覆盖利用技术探讨延缓玉米叶片衰老并增加玉米产量的可行性,以期为构建西北绿洲灌区地膜减量玉米高效生产技术提供理论支撑。2013年在西北绿洲灌区设置免耕一膜2年覆盖利用(NTP)、秋免耕春覆膜(RTP)和传统每年覆新膜(对照, CTP) 3种处理(本文采用2021-2023数据),探究玉米叶片光合源、持绿特性、细胞抗氧化酶活性和渗透调节物质含量对不同地膜覆盖利用方式的响应。结果表明,NTP和RTP可有效调节玉米生育期内光合源和叶片持绿性能的动态关系,维持生育后期较大的叶面积指数(LAI)、光合势(LAD)、叶片持绿性(SG)和叶绿素相对含量(SPAD),有利于延缓叶片衰老。与CTP相比, NTP玉米出苗后75~120 d的LAI、LAD、SG和SPAD分别提高15.1%~16.1%、14.8%~15.5%、7.2%~9.2%和11.3%~11.7%,RTP分别提高12.4%~13.0%、11.5%~12.4%、10.0%~17.6%和6.0%~6.7%。同时,通过单株绿色叶面积的拟合,发现NTP和RTP较CTP叶片衰老时间平均推迟了5.8~7.0d和6.2~7.7d,这可能是由于NTP和RTP有助于增强玉米大喇叭口期-灌浆期叶片的抗氧化能力和细胞渗透调节作用。玉米出苗后60~105 d, NTP较CTP叶片抗氧化酶(SOD、POD、CAT和APX)活性分别提高17.6%~20.0%、28.4%~34.4%、6.7%~8.4%和8.3%~10.9%, RTP较CTP分别提高11.3%~11.7%、16.9%~18.2%、4.4%~6.1%和5.8%~7.7%。此外,与CTP相比,NTP与RTP可溶性蛋白和脯氨酸含量分别提高35.9%~43.9%和29.5%~31.8%,20.7%~31.7%和17.4%~20.4%,丙二醛含量分别降低26.0%~27.8%和17.5%~25.9%。NTP对抗氧化酶和渗透调节物质的影响更大,NTP较CTP增产5.2%~6.0%。免耕一膜2年覆盖利用技术是西北灌区在实现资源减投条件下,有效延缓玉米叶片衰老且增加产量的适宜措施。 展开更多
关键词 地膜覆盖 光合源 抗氧化酶活性 细胞渗透调节能力 籽粒产量
下载PDF
配方施肥对薄壳山核桃生长及土壤性状的影响
8
作者 杜洋文 周倩 +2 位作者 杜拾平 程军勇 张荣洋 《西南大学学报(自然科学版)》 CAS 北大核心 2025年第1期178-188,共11页
为探索薄壳山核桃幼林生长发育的适宜施肥配方,采用氮、磷、钾3因素4水平16个处理的正交试验设计,探究不同施肥配方对薄壳山核桃幼林生长、土壤酶活性、土壤养分含量及叶片矿质养分含量的影响。结果表明:影响幼林树高和茎粗增长量大小... 为探索薄壳山核桃幼林生长发育的适宜施肥配方,采用氮、磷、钾3因素4水平16个处理的正交试验设计,探究不同施肥配方对薄壳山核桃幼林生长、土壤酶活性、土壤养分含量及叶片矿质养分含量的影响。结果表明:影响幼林树高和茎粗增长量大小的肥料主次顺序为:尿素、氯化钾、过磷酸钙,最优水平组合为:尿素0.45 kg/株+过磷酸钙1.71 kg/株+氯化钾0.28 kg/株;影响叶片氮、磷、钾含量高低的肥料主次顺序为:氯化钾、尿素、过磷酸钙,最优水平组合为:尿素0.11 kg/株+过磷酸钙0.85 kg/株+氯化钾0.46 kg/株;影响土壤有效氮、磷、钾及有机质含量高低的肥料主次顺序为:尿素、氯化钾、过磷酸钙,最优水平组合为:尿素0.33 kg/株+过磷酸钙1.28 kg/株+氯化钾0.28 kg/株;影响土壤酶活性高低的肥料主次顺序为:尿素、过磷酸钙、氯化钾,最优水平组合为:尿素0.22 kg/株+过磷酸钙0.85 kg/株+氯化钾0.28 kg/株。树高和茎粗增长量与叶片全氮和全磷含量存在显著负相关,土壤蔗糖酶与土壤有效氮、磷、钾存在显著正相关。总体上,对薄壳山核桃幼林生长发育影响的肥料主次顺序为:尿素、氯化钾、过磷酸钙,最优施肥水平组合为尿素0.45 kg/株+过磷酸钙0.85 kg/株+氯化钾0.28 kg/株。 展开更多
关键词 配方施肥 薄壳山核桃 生长 土壤酶 土壤养分 叶片养分
下载PDF
连作辣椒土壤理化性状及土壤酶活性对微生物菌剂的响应
9
作者 高晶霞 张风宝 +3 位作者 许旺旺 席维娜 裴红霞 谢华 《北方园艺》 北大核心 2025年第1期115-121,共7页
以辣椒为研究对象,以5种微生物菌剂为试验材料,开展不同微生物菌剂对辣椒土壤改良效果,筛选出能够缓解辣椒连作障碍及合适的微生物菌剂,以期得到当地最优的微生物菌剂,为宁南连作辣椒改良技术集成提供参考依据。结果表明:施加微生物菌... 以辣椒为研究对象,以5种微生物菌剂为试验材料,开展不同微生物菌剂对辣椒土壤改良效果,筛选出能够缓解辣椒连作障碍及合适的微生物菌剂,以期得到当地最优的微生物菌剂,为宁南连作辣椒改良技术集成提供参考依据。结果表明:施加微生物菌剂处理影响各生育期连作辣椒土壤碱性磷酸酶的活性,土壤碱性磷酸酶活性随生育期的延长呈现先升高后略有下降的趋势;微生物菌剂处理下土壤速效钾含量随各生育期变化不大,但显著影响开花期和成熟期土壤有机质含量;不同微生物菌剂处理对不同生育期的土壤全磷含量影响程度不同。综上所述,施加微生物菌剂均对缓解辣椒连作障碍表现出积极的正向作用。 展开更多
关键词 菌剂 辣椒 土壤酶活性 土壤理化性状
下载PDF
植物+微生物联合生态沟渠在盐度胁迫下的营养盐去除效果
10
作者 杨文焕 彭耀华 +3 位作者 徐岩 姚植 王乐乐 李卫平 《中国环境科学》 北大核心 2025年第1期430-439,共10页
为实现高效去除高盐湖体营养盐,以岱海湖为研究对象,本文基于混合植物生态沟渠技术,探究了植物+微生物联合生态沟渠在不同盐度梯度下对营养盐的去除效率、植物生长情况和微生物群落变化.研究发现,盐度胁迫下利用聚氨酯海绵将解淀粉芽孢... 为实现高效去除高盐湖体营养盐,以岱海湖为研究对象,本文基于混合植物生态沟渠技术,探究了植物+微生物联合生态沟渠在不同盐度梯度下对营养盐的去除效率、植物生长情况和微生物群落变化.研究发现,盐度胁迫下利用聚氨酯海绵将解淀粉芽孢杆菌固定在沟渠,能有效的强化系统中植物的耐盐性能,主要体现在促进植物生长、提高植物的抗氧化应激功能酶活性,加强植物对营养盐的同化吸收等.虽然向沟渠中投加解淀粉芽孢杆菌并未使其成为系统中的绝对优势菌属,但其能够改善系统中微生物群落结构,提高系统中脱氮除磷相关功能微生物的丰度进而提高沟渠的水质净化能力.结果表明,植物+微生物组沟渠在不同盐度下对水质的净化效果均显著高于单一植物/微生物生态沟渠,且在15g/L盐度下对营养盐去除效率最高,总氮(TN)、氨氮(NH_(4)^(+)-N)、总磷(TP)和化学需氧量(COD_(Cr))平均去除率均达到70%以上.相较于植物沟渠,植物+微生物沟渠的3种抗氧化应激酶:超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)在15g/L盐度条件下分别提高了33.70%、43.64%、38.68%. 展开更多
关键词 解淀粉芽孢杆菌 生态沟渠 盐度胁迫 抗氧化应激酶
下载PDF
干旱胁迫对沙蒿叶片水分含量、光合特性及抗氧化酶的影响
11
作者 柴成武 王方琳 +2 位作者 赵鹏 付贵全 唐卫东 《西北林学院学报》 北大核心 2025年第1期42-50,共9页
以2年生沙蒿实生苗为材料,通过盆栽控水试验测定不同水分条件沙蒿叶片水分含量、光合特性及抗氧化酶活性,分析各指标在干旱胁迫过程中的变化特征、响应机制及其与土壤水分的定量关系,揭示沙蒿对干旱胁迫的响应规律。结果表明,1)随着干... 以2年生沙蒿实生苗为材料,通过盆栽控水试验测定不同水分条件沙蒿叶片水分含量、光合特性及抗氧化酶活性,分析各指标在干旱胁迫过程中的变化特征、响应机制及其与土壤水分的定量关系,揭示沙蒿对干旱胁迫的响应规律。结果表明,1)随着干旱胁迫时间增加,沙蒿叶片相对含水量(RWC)持续降低,叶片水分亏缺(RWD)呈波动式上升趋势;2)沙蒿总叶绿素(Chl)、叶绿素a(Chla)和叶绿素b(Chlb)含量均随胁迫时间增加而持续降低,胁迫30 d时均降为最小值,而类胡萝卜素含量随胁迫时间增加逐渐升高;3)沙蒿净光合速率(P_(n))、蒸腾速率(T_(r))、水分利用效率(WUE)等主要气体交换参数对土壤水分都表现出明显的阈值响应,适宜进行正常光合生理活动的土壤含水率阈值为6.48%~17.51%;4)沙蒿PSⅡ最大光化学效率(F_(v)/F_(m))、有效光化学量子效率(F_(v)′/F_(m)′)及光化学淬灭系数(qP)均随干旱胁迫时间增加而逐渐降低,而非光化学淬灭系数(NPQ)呈平缓上升趋势;5)沙蒿叶片中丙二醛(MDA)含量随胁迫时间增加而升高,持续干旱胁迫导致MDA大量积累;超氧化物歧化酶(SOD)活性也随胁迫时间增加而升高,30 d时达到最大值;过氧化物酶(POD)活性能对干旱胁迫做出较早的响应,胁迫12 d时达到峰值;过氧化氢酶(CAT)活性对干旱胁迫的敏感性较差,持续干旱对沙蒿CAT活性产生抑制。研究发现,在干旱胁迫条件下,沙蒿会通过提高叶片光能捕获转换能力、增强抗氧化水平等方式适应干旱环境。 展开更多
关键词 沙蒿 干旱胁迫 叶片水分含量 光合特性 抗氧化酶活性
下载PDF
新型倒置A^(2)/O耦联MBR组合工艺处理农村低C/N废水的研究
12
作者 韩卫萍 盖磊 《水处理技术》 CAS 北大核心 2025年第1期114-119,共6页
针对农村低C/N污水污染物和营养盐去除率差的问题,以倒置A^(2)/O耦联膜生物反应器(MBR)组合工艺为探究对象,通过控制进水污染物浓度,在中温条件下考察了有机负荷(OLR)对倒置A^(2)/O耦联MBR组合工艺处理农村低C/N污水的影响。结果表明,OL... 针对农村低C/N污水污染物和营养盐去除率差的问题,以倒置A^(2)/O耦联膜生物反应器(MBR)组合工艺为探究对象,通过控制进水污染物浓度,在中温条件下考察了有机负荷(OLR)对倒置A^(2)/O耦联MBR组合工艺处理农村低C/N污水的影响。结果表明,OLR由150 mg/L提高至450 mg/L时,总氮(TN)和溶解性磷酸盐(SOP)去除率分别由67.6%和86.6%提高至72.4%和94.3%,进一步提高OLR降低了组合工艺对污染物和营养盐的去除。此外,OLR能影响新工艺内污泥特征,提高OLR促进了胞外聚合物(EPS)分泌,尤其在OLR为600 mg/L组别内,EPS含量提高至139.6 mg/g。进水OLR对缺氧池内EPS的影响要大于其对厌氧池内EPS的影响。OLR能影响新工艺内污染物和营养盐去除相关关键酶的活性,当OLR为450 mg/L时,污染物和营养盐去除相关关键活性酶最强。研究结果为农村低C/N污水的高效处理提供了理论依据和数据支撑。 展开更多
关键词 农村低C/N污水 倒置A^(2)/O MBR 胞外聚合物 关键酶
下载PDF
饲粮添加不同水平猪源植物乳杆菌对断奶仔猪消化功能的影响
13
作者 周媛丽 姚明霞 +4 位作者 杨家军 殷秀慧 张雨杰 翟苏晴 王静 《饲料工业》 北大核心 2025年第1期51-57,共7页
试验旨在探究饲粮中添加不同剂量的植物乳杆菌对断奶仔猪消化吸收功能影响。体外培养植物乳杆菌,检测产消化酶活性;选取健康、平均体重为(6.80±0.23) kg的28日龄断奶仔猪160头,随机分为4组,每组40头。对照组饲喂基础日粮,试验1、2... 试验旨在探究饲粮中添加不同剂量的植物乳杆菌对断奶仔猪消化吸收功能影响。体外培养植物乳杆菌,检测产消化酶活性;选取健康、平均体重为(6.80±0.23) kg的28日龄断奶仔猪160头,随机分为4组,每组40头。对照组饲喂基础日粮,试验1、2、3组分别在基础日粮中添加3‰植物乳杆菌液体制剂、6‰植物乳杆菌液体制剂、3 mg/kg金霉素,试验期28 d。饲喂7 d后,连续7 d收集猪粪,采用指示剂法检测饲粮养分表观消化率。28 d后称重,计算各组仔猪平均日采食量(ADFI)和平均日增重(ADG);采集十二指肠,检测内容物消化酶活性;采集回肠,检测回肠菌群组成。结果表明:植物乳杆菌可分泌蛋白酶、脂肪酶、α-淀粉酶、β-淀粉酶,活性分别为698.29、164.47、209.29、728.41 U/mL。与对照组相比,试验1组断奶仔猪体重提高了1.56 kg(P<0.05),ADG提高了41 g(P<0.05);与对照组相比,试验1组十二指肠内容物蛋白酶、脂肪酶、α-淀粉酶、β-淀粉酶活性水平显著提高(P<0.05);与对照组相比,试验1组仔猪回肠菌群改善,乳酸菌和双歧杆菌数量显著升高(P<0.05),肠球菌、大肠杆菌和沙门氏菌显著降低(P<0.05);试验1组猪粪水分含量、粗纤维含量、能量值显著低于对照组(P<0.05)。综上,植物乳杆菌可分泌多种消化酶,饲粮中添加3‰植物乳杆菌制剂可显著提高断奶仔猪肠道对营养的消化吸收,促进生长性能,降低死淘率,改善养殖效率。 展开更多
关键词 断奶仔猪 植物乳杆菌 生产 消化酶 功能
下载PDF
超高压辅助酶法制备黑斑蛙皮抗氧化肽及其活性评估
14
作者 张喜才 李蓉 黄业传 《食品工业科技》 北大核心 2025年第4期167-175,共9页
为提高黑斑蛙加工副产物蛙皮的综合利用价值,对黑斑蛙蛙皮抗氧化肽的提取工艺及性能进行研究。采用超滤方法对黑斑蛙蛙皮的蛋白酶解液进行分离,得到不同分子量范围的小分子肽,通过体外抗氧化试验和秀丽隐杆线虫模型,评价不同分子量范围... 为提高黑斑蛙加工副产物蛙皮的综合利用价值,对黑斑蛙蛙皮抗氧化肽的提取工艺及性能进行研究。采用超滤方法对黑斑蛙蛙皮的蛋白酶解液进行分离,得到不同分子量范围的小分子肽,通过体外抗氧化试验和秀丽隐杆线虫模型,评价不同分子量范围蛙皮小分子肽的抗氧化性能;以高活性小分子肽得率为目标,采用响应面方法对酶添加量、超高压压力、超高压时间、液料比四个参数优化,确定小分子肽最佳提取工艺。结果表明,1~2000 Da小分子肽具有最强的抗氧化能力,DPPH自由基、ABTS^(+)自由基清除率分别达到了76.93%、59.23%,并显著提高了秀丽隐杆线虫的抗氧化能力;在中性蛋白酶水解的基础上,二次酶解最佳工艺参数为碱性蛋白酶用量10210 U/g,超高压压力315 MPa,压力作用时间9.3 min,液料比16倍,1~2000 Da小分子肽得率为25.26%。超高压辅助双酶水解显著提高了黑斑蛙蛙皮小分子肽的得率,为黑斑蛙副产物的高值化利用提供了参考。 展开更多
关键词 超高压 双酶水解 黑斑蛙皮 小分子肽 抗氧化性能
下载PDF
Recent advances in immobilized enzymes on nanocarriers 被引量:12
15
作者 曹诗林 徐培 +5 位作者 马永正 姚潇晓 姚远 宗敏华 李雪辉 娄文勇 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2016年第11期1814-1823,共10页
Recent progress in nanotechnology has provided high-performance nanomaterials for enzyme immobilization.Nanobiocatalysts combining enzymes and nanocarriers are drawing increasing attention because of their high cataly... Recent progress in nanotechnology has provided high-performance nanomaterials for enzyme immobilization.Nanobiocatalysts combining enzymes and nanocarriers are drawing increasing attention because of their high catalytic performance,enhanced stabilities,improved enzyme-substrate affinities,and reusabilities.Many studies have been performed to investigate the efficient use of cellulose nanocrystals,polydopamine-based nanomaterials,and synthetic polymer nanogels for enzyme immobilization.Various nanobiocatalysts are highlighted in this review,with the emphasis on the design,preparation,properties,and potential applications of nanoscale enzyme carriers and nanobiocatalysts. 展开更多
关键词 Enzyme immobilization Cellulose nanocrystal POLYDOPAMINE Biodegradable material
下载PDF
冻融期土壤理化性质及酶活性对秸秆还田的响应
16
作者 李富 董道旭 +2 位作者 郑大劲 李维刚 葛宜元 《现代农业研究》 2025年第2期1-13,共13页
为了能够进一步提高三江平原水稻秸秆腐解率和改善土壤理化性质。本研究采用室内冻融模拟试验,实验设定A(-10~10℃)和B(-20~20℃)两种冻融幅度,1(150%)、2(200%)两种土壤持水量,以及3(3 cm)、5(5 cm)和10(10 cm)三种秸秆长度。试验设定... 为了能够进一步提高三江平原水稻秸秆腐解率和改善土壤理化性质。本研究采用室内冻融模拟试验,实验设定A(-10~10℃)和B(-20~20℃)两种冻融幅度,1(150%)、2(200%)两种土壤持水量,以及3(3 cm)、5(5 cm)和10(10 cm)三种秸秆长度。试验设定冻24小时后融24小时为一次冻融循环(Freeze-thaw cycle,FTC)过程,15 d取一次样,共设置6次取样(90 d)后常温培养(30 d),总时长为120 d的室内冻融模拟,在每次冻融结束后测定土壤理化性质及相关酶活性。试验结果显示,施加菌剂提升了秸秆腐解速率,秸秆配施菌剂还田显著降低冻融期三江平原土壤容重与0.5~1 mm粒径的团聚体数量,增加了土壤孔隙度,且在大幅度冻融循环表现最为明显。秸秆还田显著提高了土壤有机碳(TOC)、总磷(TP)、总钾(TK),但土壤全氮显著降低,不同冻融幅度差异不显著。秸秆还田配施菌剂显著提高了冻融期土壤淀粉酶、蔗糖酶和纤维素酶活性,而不同冻融幅度与冻融循环次数对土壤酶活性均产生影响,且随着冻融时长的增加而减弱。不同冻融幅度和不同的持水量对土壤淀粉酶活性影响显著,对土壤蔗糖酶活性影响不显著。秸秆还田配施菌剂对冻融期土壤理化性质具有显著影响,而对土壤酶活性的影响具有差异性。因此,秸秆还田配施菌剂对于三江平原冻融期土壤提升土壤肥力具有重要意义。 展开更多
关键词 低温菌剂 土壤理化性质 冻融期 土壤酶活性
下载PDF
DMES:一个实时控制专家系统 被引量:7
17
作者 梁军 杨永耀 吕勇哉 《信息与控制》 CSCD 北大核心 1993年第2期65-70,共6页
人工智能在一些领域中的成功应用,引起了控制界的注意,能否利用知识概念和自学习功能解决控制领域的问题,即所谓智能控制,正成为一个有光辉前景的研究领域。本文以冶金加热炉为实际工业背景,针对其复杂大系统的特点,研究开发了一个基于... 人工智能在一些领域中的成功应用,引起了控制界的注意,能否利用知识概念和自学习功能解决控制领域的问题,即所谓智能控制,正成为一个有光辉前景的研究领域。本文以冶金加热炉为实际工业背景,针对其复杂大系统的特点,研究开发了一个基于混合知识的实时专家控制系统DMES并进行了实施,取得了良好的控制效果。 展开更多
关键词 实时控制 专家系统 dmes
下载PDF
Effect of ^(12)C^(6+) Ions Beam Irradiation on Seed Germination and Enzymes Activity in Seedlings of Sweet Sorghum 被引量:10
18
作者 冯亮英 董喜存 +7 位作者 李文建 马晓琪 马爽 余丽霞 李岩 刘清芳 何金玉 曲颖 《Agricultural Science & Technology》 CAS 2009年第5期22-25,共4页
[ Objective] The aim was to study the effect of 12C6 + ions beam irradiation to two varieties of sweet sorghum on seed germination and some enzymes activity in seedlings with different doses, and provided a theoretic... [ Objective] The aim was to study the effect of 12C6 + ions beam irradiation to two varieties of sweet sorghum on seed germination and some enzymes activity in seedlings with different doses, and provided a theoretical foundation for sweet sorghum breeding. [ Method] After germination, the germination potential, germination fraction and enzyme activity were detected, respectively. [ Result] The results showed that with the dose increased, the germination potential of sweet sorghum increased first and then decreased, while their germination fraction presented "shoulder like shape" ; the activity of LDH, SOD, CAT and GSH-Px increased first and then decreased with doses, they presented slight differences among different enzymes. [ Conclusion] Low dose radiation could accelerate germination of sweet sorghum seeds and enzyme activity could remain at a relatively high level. Enzyme activity decreased with high doses and the growth of sweet sorghum was inhibited. 展开更多
关键词 Heavy ions Sweet sorghum Germination potential Seedling rate Enzyme activity
下载PDF
Effect of Different Arbuscular Mycorrhizal Fungi Strains on Mineral Nutrition and Antioxidant Enzymes of Chrysanthemum morifolium 被引量:12
19
作者 孔佩佩 杨树华 +1 位作者 贾瑞冬 葛红 《Agricultural Science & Technology》 CAS 2011年第10期1477-1480,共4页
[Objective] The purpose was to study the effects of different arbuscular mycorrhizal fungi strains(AMF)on the mineral nutrition and antioxidant enzymes of Chrysanthemum morifolium.[Method] The pot experiment was con... [Objective] The purpose was to study the effects of different arbuscular mycorrhizal fungi strains(AMF)on the mineral nutrition and antioxidant enzymes of Chrysanthemum morifolium.[Method] The pot experiment was conducted in the greenhouse,C.morifolium 'Jinba' was inoculated with five kinds of AMF,N,P,K,malondial dehyde(MDA)content,as well as the superoxide dismutase(SOD),peroxidase(POD) and catalase(CAT) activity in roots,leaves and petals of C.morifolium were measured at seedling and flowering stages.[Result] The G.i,G.e and G.m treatments could promote mineral nutrient absorption,increase N,P,K content in roots,leaves and petals of C.morifolium compared with the control without inoculation.The G.d、G.e and G.m treatments could significantly reduce MDA content in roots and petals,thus alleviating membrane permeability and lipid peroxidation.The G.i treatments could also improve the SOD,POD and CAT activities of C.morifolium,thereby increasing the capability of scavenging oxygen free radicals.[Conclusion] According to the comprehensive analysis,G.i was screened out as the best strain to improve mineral nutrition and antioxidant enzyme activities of C.morifolium. 展开更多
关键词 Chrysanthemum morifolium Arbuscular mycorrhizal fungi Mineral nutrition Antioxidant enzymes
下载PDF
Effects of Adaptation to Elevated Salinity on Some Enzymes' Salt_tolerance in Vitro and Physiological Changes of Eelgrass 被引量:20
20
作者 叶春江 赵可夫 《Acta Botanica Sinica》 CSCD 2002年第7期788-794,共7页
The eelgrass ( Zostera marina L.) was treated with artificial seawater (ASW) of different salinities ( 100%, 150% and 200% seawater) for 5 d. The activities of two enzymes extracted from the plant leaves were determin... The eelgrass ( Zostera marina L.) was treated with artificial seawater (ASW) of different salinities ( 100%, 150% and 200% seawater) for 5 d. The activities of two enzymes extracted from the plant leaves were determined under a salinity grade in vitro So were the photosynthesis rates of the plants from the three treatments in the media with different salinities 100%, 150%, 200%, 300% ASW) and Some physiological data. The data showed that under increased salinities (concentrated seawater), Na+, Cl-, MDA (malon dialdehyde) and glucose contents and the osmotic potentials ( absolute value) in the leaves increased with the salinity elevation in the medium (ASW), but both K+ and free amino acid (mainly proline) contents decreased. Malate dehydrogenase (MDH) from the plant leaves under a salinity grade showed its activities (A) as follows: A(100%) (ASW) > A(150%) (ASW) > A(200%) (ASW). Phosphoenolpyruvate carboxylase (PEPC) extracted from the 100% ASW- and 200% ASW-treated plants showed similar activities (both insensitive to salinities) under the salinity grade in vitro, but the activities of PEPC from plants treated with 150% ASW were dependent oil salinity. Whether the plant is stressed at 150% ASW and can stand higher salinity than seawater needs to be studied further. Meantime, die data do not agree with the opinion that the adaptation of the eelgrass to seawater salinity is partly fulfilled by its insensitiveness to salinities in Some metabolic enzymes. It can be inferred that the lack of transpiration may be an important aspect of tire plant's tolerance to seawater salinity. 展开更多
关键词 EELGRASS salinity adaptation enzyme salt tolerance PEPC MDHI MDA
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部