Physicochemical, antimicrobial, and cytotoxic characteristics of a chitosan film cross-linked by a naturally occurring cross-linking agent, aglycone geniposidic acid   总被引：2，自引：0，他引：2  

Mi FL  Huang CT  Liang HF  Chen MC  Chiu YL  Chen CH  Sung HW 《Journal of agricultural and food chemistry》2006,54(9):3290-3296

The purpose of this study was to evaluate the characteristics of a chitosan film cross-linked by a naturally occurring compound, aglycone geniposidic acid (aGSA). This newly developed aGSA-cross-linked chitosan film may be used as an edible film. The chitosan film without cross-linking (fresh) and the glutaraldehyde-cross-linked chitosan film were used as controls. The characteristics of test chitosan films evaluated were their degree of cross-linking, swelling ratio, mechanical properties, water vapor permeability, antimicrobial capability, cytotoxicity, and enzymatic degradability. It was found that cross-linking of chitosan films by aGSA (at a concentration up to 0.8 mM) significantly increased its ultimate tensile strength but reduced its strain at fracture and swelling ratio. There was no significant difference in the antimicrobial capability between the cross-linked chitosan films and their fresh counterpart. However, the aGSA-cross-linked chitosan film had a lower cytotoxicity, a slower degradation rate, and a relatively lower water vapor permeability as compared to the glutaraldehyde-cross-linked film. These results suggested that the aGSA-cross-linked chitosan film may be a promising material as an edible film.  相似文献   

Principal component analysis and discriminant analysis (PCA-DA) for discriminating profiles of terminal restriction fragment length polymorphism (T-RFLP) in soil bacterial communities     

Sangkyu Park  Mi Ja Seo  Ji Eun Yeon  Soon-Chun Jeong  Chee Hark Harn 《Soil biology & biochemistry》2006,38(8):2344-2349

To assess the impact of a transgenic crop on soil environment, we compared soil bacterial communities from the rhizospheres of cucumber green mottle mosaic virus (CGMMV)-resistant transgenic watermelon (Citrullus vulgaris [Twinser] cv. Gongdae) and non-transgenic parental line watermelon at an experimental farm in Miryang, Korea. Soil microbial community structure was studied using terminal restriction fragment length polymorphism (T-RFLP) using HaeIII and HhaI enzymes on products from polymerase chain amplification reactions (PCR) of total DNA from rhizosphere. We used principal component analyses (PCA) to reduce dimensionality of T-RFLP profiles before comparison. On these PCA scores, we conducted discrimination analyses to compare soil microbial communities from the rhizosphere of transgenic and non-transgenic. Discriminant analyses indicate that microbial communities from rhizosphere of transgenic and non-transgenic watermelon did not differ with significance at 95% level. Our study could be used as a model case to assess the environmental risk assessment of transgenic crops on soil microbial organisms.  相似文献   

气候变化及农户适应性行为对大豆播种面积的影响     

张雪  周密  张丽敏 《农业现代化研究》2021,42(1):153-164

气候变化通过改变环境禀赋影响作物间的比较优势。在2019年中央"一号文件"提出"大豆振兴计划"背景下,农户会根据气候变化情况调整种植结构还是调整生产资料投入?如何影响大豆播种面积?其作用机理是什么?本文基于1998—2017年3560份地级市数据,运用动态面板差分广义矩模型(DIF-GMM),考察了气候变化对大豆播种面积占比的影响。研究发现:日照、气温和降水均会影响大豆播种面积占比,进一步作用机制分析发现,气候变化主要是通过影响大豆单位面积产量,进而影响其播种面积占比。农户的适应性行为在气候变化对大豆播种面积占比的影响中起调节作用,其中,灌溉、地膜和化肥在气温对大豆播种面积占比的影响具有正向调节作用,调节降水变化的要素主要是灌溉。同时,进口量、相对收益以及生产成本也是影响大豆播种面积占比变化的重要因素。在此基础上,本文还运用面板向量自回归模型(PVAR)对未来十年气候变化及农户适应性行为对大豆播种面积占比的动态影响路径和影响程度进行了预测分析,发现化肥和农药施用量可在短期内缓解气候变化对大豆播种面积占比的影响,而日照、降水、灌溉和地膜将对大豆播种面积占比具有长期持续冲击。  相似文献   

宁夏星海湖湿地水环境污染评价及可持续利用研究     

王亚娟  米文宝  王莉  刘小鹏 《农业科学研究》2010,31(4)

综合整治湖泊湿地水环境污染,对于促进西北干旱区湖泊湿地资源可持续利用意义重大.根据宁夏石嘴山市星海湖2009年监测原始数据,对星海湖湿地水环境污染现状进行模糊评价.结果表明:纪念碑监测点水质为Ⅲ级,码头和南域指挥部监测点水质均为Ⅳ级.主要污染物为有机污染物和重金属,污染源为工业污染,主要是附近的化工厂、洗煤厂、机械制造厂等.进一步提出星海湖湿地可持续利用的对策.  相似文献   

小麦优质Ax1/Ax2*和Dx5亚基的二重AS-PCR分子鉴定          下载免费PDF全文

孙宪印吴科  钱兆国米勇 牟秋焕郭营  李斯深 《农学学报》2013,3(5):8-11

为了提高小麦Glu-A1位点Ax1/Ax2*亚基和Glu-D1位点Dx5亚基分子标记鉴定效率,方便小麦分子水平的辅助选择及品种评价,建立了小麦高分子量谷蛋白Ax1/Ax2*亚基及Dx5亚基基因的二重AS-PCR反应体系。结果表明,PCR鉴定结果与SDS-PAGE电泳结果一致。利用建立的二重AS-PCR稳定扩增体系鉴定了21份外引小麦品种系的谷蛋白Glu-A1及Glu-D1位点,有7个品种扩增出1500 bp特异片段,表明具有Ax1/Ax2*亚基;有11个品种扩增出478 bp特异片段,表明具有Dx5亚基;小麦优质Ax1/Ax2*亚基和Dx5亚基出现百分率分别为33.3%和52.4%。该反应体系扩增稳定,可同时鉴定Ax1/Ax2*亚基及Dx5亚基,适用于优质小麦新品种的辅助选择。  相似文献   

海洋微生物溶菌酶体外抗菌抗病毒活性研究   总被引：3，自引：0，他引：3  

张琇  吴发兴  孙谧  王清印  王跃军  杨向科 《中国农业科学》2007,40(11):2626-2631

 【目的】初步研究海洋微生物溶菌酶S-12-86（MMLS）体外抑菌与抗病毒活性。【方法】采用最小抑菌浓度（MIC）和最小杀菌浓度法（MBC）测定MMLS对部分模式菌的抑菌和杀菌作用；通过细胞病变抑制实验法（CPE），研究MMLS在猪肾细胞（PK-15）中对伪狂犬病毒（PRV）的抑制作用。【结果】MMLS对革兰氏阳性菌，革兰氏阴性菌及真菌均有抑菌作用，抑菌作用的浓度范围在0.25～4.00 mg•ml-1之间，杀菌作用的浓度范围一般在0.25～8.00 mg•ml-1之间。在电镜下，可见MMLS能够使大部分白色念珠球菌的细胞壁出现严重变形，细胞质出现不均匀，细菌胞质中的空腔增多。MMLS的TC50为100.0 µg•ml-1，抑制伪狂犬病毒的半数有效浓度（EC50）为0.46 µg•ml-1，治疗指数（TI）为217；在病毒感染后的0、2、4、6和8 h添加MMLS，均有抑制伪狂犬病毒的作用。【结论】MMLS具有广谱的抑菌作用和抗伪狂犬病毒作用。  相似文献   

旋流式流化床丸化装置数值模拟及试验     

仇义  戴念祖  陈智  侯占峰  吴霜  弭龙凯 《农机化研究》2022,44(7):167-173

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Quercetin Increased Protein Utilization and Decreased Nitrogen Excretion in Broilers by Activating TOR Signaling Pathway     

Xiao Feng-lin  Mao Yan-jun  Ying Lin-lin  Wang Mi  Wang Shan-shan  Wang Bo  Li Yao 《东北农业大学学报(英文版)》2021,28(2):77-87

The study was conducted to investigate the effect and mechanism of dietary quercetin supplementation on protein utilization of Arbor Acres (AA) broilers.A total of 240 1-day-old AA broilers were randomly allocated to four treatments with six replicates,comprising 10 broilers each replicate (60 broilers per treatment).Birds were fed either a corn-soybean meal basal diet without quercetin (control) or a basal diet supplemented with 0.2,0.4 or 0.6 g of quercetin per kg feed,and the trial lasted 42 days.Dietary quercetin supplementation tended to increase the apparent metabolic rate of protein (p=0.076) and the content of serum albumin (p=0.062) in AA broilers.Compared with the control,dietary quercetin supplementation increased the contents of protein in breast muscle (p0.05) and in thigh muscle (p=0.053).In addition,quercetin up-regulated mRNA expression of insulin-like growth factor 1 (IGF-1),phosphatidylinositol 3-kinase (PI3K),target of rapamycin (TOR),ribosomal protein S6 kinase 1 (S6K1),eukaryotic translation initiation factor 4E (eIF4E),eukaryotic translation initiation factor 4G (eIF4G),eukaryotic elongation factor 2 (eEF2) and eukaryotic translation initiation factor 4B (eIF4B) genes and down-regulated mRNA expression of eukaryotic elongation factor 2 kinase (eEF2K) and eukaryotic initiation factor 4E binding protein1 (4E-BP1) genes in breast muscle,thigh muscle and liver of AA broilers (p0.05).The present results suggested that dietary quercetin supplementation enhanced protein utilization in broilers by activating TOR signaling pathway.  相似文献   

果粮间作生态系统光能分布规律的研究   总被引：1，自引：0，他引：1  

李连国  崔学明  李晓燕  米志恒  杨焕之 《内蒙古农业大学学报(自然科学版)》1998,(3)

对内蒙古巴盟地区果粮间作生态系统的光能分布研究表明：果粮间作生态系统有其特殊的光照分布规律;果粮间作生态系统可更好地利用光能;根据果粮间作生态系统的光照分布规律可以确定合理的栽植方式和合理的树形、树高、冠幅等指标。  相似文献   

Treatment of autoimmune neuroinflammation with a synthetic tryptophan metabolite   总被引：1，自引：0，他引：1  

Platten M  Ho PP  Youssef S  Fontoura P  Garren H  Hur EM  Gupta R  Lee LY  Kidd BA  Robinson WH  Sobel RA  Selley ML  Steinman L 《Science (New York, N.Y.)》2005,310(5749):850-855

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