共查询到17条相似文献，搜索用时 125 毫秒
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植物几丁质酶及其基因工程研究进展 总被引：4，自引：0，他引：4
几丁质是构成大多数真菌细胞壁的主要成分.几丁质酶广泛存在于植物、动物及微生物细胞和组织中,参与多种生理过程.研究发现,许多微生物都可以产生几丁质酶,几丁质酶的生物活性可显著抵抗植物真菌病害.目前有多种植物、微生物几丁质酶基因已经被克隆出来,并有部分已经转化应用于植物抗病,有些显现出良好效果. 相似文献
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几丁质是虾、蟹、昆虫和其他节肢动物体壁(即外壳、外骨胳)的基本成分。它在真菌的细胞壁中也被发现。几丁质是由数百个以上的N—乙酰—D—葡萄糖胺组成的链状含氮高分子聚合物。几丁质无色,无定型固体。比较柔韧,不溶于水、酒精、乙醚、稀酸和稀碱,但能为水所渗透。几丁质和蛋白质是节肢动物体壁表皮的主要成分。表皮的弹性、韧度等重要物理性质,主要 相似文献
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微生物几丁质酶的研究和应用 总被引：5，自引：0，他引：5
杨学敏 《Journal of Zhangzhou Technical Institute》2005,7(1):7-11
本文从产几丁质酶的微生物类群及微生物产几丁质酶的种类、特点、理化性质、三级结构、作用机制和分子生物学等方面论述了微生物几丁质酶的研究进展及其应用进展,尤其是在害虫防治中的增效作用,提出研究和应用中所面临的问题,以期进一步解决. 相似文献
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植物几丁质酶的生物学作用 总被引：1，自引：0，他引：1
几丁质酶广泛存在于多种生物中 ,包括含有其底物几丁质的真菌、昆虫等生物中 ,也存在于不含几丁质的植物中。在植物中 ,几丁质酶不仅存在于被子植物中 ,也存在于裸子植物中。在植株中 ,几丁质酶分布于根、茎、叶、花、果实、种子等器官中 ,其中种子中的酶活性高于其它器官。在正常情况下 ,植物中几丁质酶活性较低 ,但经病原物侵染等锈导因子诱导 ,活性会迅速升高 ,它主要通过水解病原菌的细胞壁以抵御侵害。近年来 ,由于其抗真菌的作用而倍受关注。1 植物几丁质酶的生物学特性植物几丁质酶主要水解几丁质多聚体的β- 1,4 -糖苷键 ,产生Ｎ -… 相似文献
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《大连大学学报》2015,(6):60-65
从假交替单胞菌(Pseudoalteromonas sp.DL-6)中克隆低温几丁质酶chiA基因(Gen Bank登录号KF234015)。该序列全长3160个核苷酸,编码1053个氨基酸,预测相对分子质量113.5 KDa,等电点(pI)4.49,命名为chiA。功能结构域分析显示其编码区包含信号肽、2个几丁质结合域、2个成人多囊肾病结构域、18家族几丁质酶催化域与18家族糖苷水解酶C端部分序列。利用Discovery Studio平台以同源建模的方法构建低温几丁质酶chi A的催化域三维结构模型,并对其进行结构优化和评估,Ramachandram图谱检测和Verify-3D评估显示模拟出的模型结构合理,整体的相容性较为可信。本结果拟为后期低温几丁质酶chiA的催化机理研究提供理论依据。 相似文献
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比较了虾几丁质酶和木瓜溶菌酶对再生几丁质与溶壁微球菌作底物时的水解速度 ,证明各有其最适底物 .两者对再生几丁质底物有不同的水解产物 ,证明一为内切酶一为外切酶 相似文献
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以黄粉虫为材料,采用盐析、亲和柱层析、Sephadex G-100分子筛及DE-52离子交换柱层析等制得纯化倍数约33倍,回收率为38%,比活力为294.7U/mg的几丁质酶制剂.在此基础上,以胶体几丁质为底物,考察黄粉虫几丁质酶的性质.结果表明：该酶催化水解几丁质的Km值为71.4mg/L;酶的最适pH值是6.0;最适温度为45℃左右;酶在pH 5.0～7.0,45℃以下酶活力稳定性较好.Na＋和K＋对酶活无影响;Ca2＋、Cu2＋对酶活起先扬后抑作用;Mn2＋、Mg2＋、Fe3＋、Al3＋对该酶活力均具有不同程度的抑制作用. 相似文献
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通过测定几丁质酶活力的方法对来源于不同寄主和采集地的16株玫烟色棒束孢进行筛选,获得活性较高菌株RCEF3304,并对高活力菌株RCEF3304产几丁质酶的pH值、装液量、接种量和温度等发酵条件进行优化研究。结果表明高酶活菌株产酶最适条件:胶体几丁质2%,NaNO33%,Mg2+0.05%,培养基初始pH值6.0,接种量12%,100 mL装液量为10 mL,温度25℃和培养时间36 h;最适发酵工艺条件下,几丁质酶酶活OD值达到0.486,比优化前发酵水平提高了128%。 相似文献
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Analysis of both chitinase and chitosanase produced by <Emphasis Type="Italic">Sphingomonas</Emphasis> sp. CJ-5 总被引：1，自引：0，他引：1
A novel chitinolytic and chitosanolytic bacterium, Sphingomonas sp. CJ-5, has been isolated and characterized. It secretes both chitinase and chitosanase into surrounding medium in response to chitin or chitosan induction. To characterize the enzymes, both chitinase and chitosanase were purified by ammonium sulfate precipitation, Sephadex G-200 gel filtration and DEAE-Sepharose Fast Flow. SDS-PAGE analysis demonstrated molecular masses of chitinase and chitosanase were 230 kDa and 45 kDa respectively. The optimum hydrolysis conditions for chitinase were about pH 7.0 and 36 °C, and these for chitosanase were pH 6.5 and 56 °C, respectively. Both enzymes were quite stable up to 45 °C for one hour at pH 5~8. These results show that CJ-5 may have potential for industrial application particularly in recycling of chitin wastes. 相似文献
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Ying-ying LU Xian YANG Wen-qing CHEN Zhen-yu JU Zhang-fei SHOU Juan JIN Xiao-hui ZHANG Jiang-hua CHEN Hong JIANG 《Journal of Zhejiang University. Science. B》2014,15(6):566-574
Aging is one of the contributing risk factors for kidney diseases. Accumulating evidence prompts the view that telomere length in kidney tissue cells is an indicator for organismal aging. Previously identified aging markers (cathelin-related antimicrobial peptide (CRAMP), stathmin, elongation factor-1α (EF-1α), and chitinase) were associated not only with telomere driven aging in mice but also with human aging and chronic diseases. This study focuses on the relationship between these biomarkers and IgA nephropathy (IgAN) progression in the Chinese population. For 260 individuals, the four markers are determined in blind datasets using direct enzyme-linked immunosorbent assay (ELISA) and immunofluorescence staining. The expression levels of CRAMP and chitinase increased in blood plasma, urine, and kidney tissues during human IgAN progression. And for the other nephropathy, such as systemic lupus erythematosus (SLE), diabetic nephropathy (DN), and focal segmental glomerulosclerosis (FSGS), there is no protein upregulation with telomere shortening. Moreover, a combination of CRAMP and chitinase can distinguish patients with IgAN from healthy individuals with 88.2%/92.5% (plasma) and 74.3%/84.2% (urine) sensitivity/specificity. These data provide the experimental evidence that telomere shortening and related inflammatory proteins are associated with human IgAN, and it could be a new direction for the disease progression study. 相似文献
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酶在食品工业、轻工业和环境保护上的应用分析 总被引：1，自引：0，他引：1
概述了酶在食品工业、轻工业和环境保护中的主要应用。这些酶主要为:淀粉酶、果胶酶、纤维素酶、β-葡萄糖苷酶、蛋白酶、脂肪酶、植酸酶、木聚糖酶、漆酶、过氧化物酶、几丁质酶和几种极端酶,并探讨一些新型酶的应用前景。 相似文献
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Linlin Luo Kenneth A. Kiewra Abraham E. Flanigan Markeya S. Peteranetz 《Instructional Science》2018,46(6):947-971
There has been a shift in college classrooms from students recording lecture notes using a longhand pencil-paper medium to using laptops. The present study investigated whether note-taking medium (laptop, longhand) influenced note taking and achievement when notes were recorded but not reviewed (note taking’s process function) and when notes were recorded and reviewed (note taking’s product function). One unique aspect of the study was determining how laptop and longhand note taking influence the recording of lecture images in notes and image-related achievement. Note-taking results showed that laptop note takers recorded more notes (idea units and words) and more verbatim lecture strings than did longhand note takers who, in turn, recorded more visual notes (signals and images) than did laptop note takers. Achievement results showed that when taking laptop notes, the process function of note taking was more beneficial than the product function of note taking (i.e., better image-related learning and similar text-related learning). When taking longhand notes, the product function of note taking was more beneficial than the process function of note taking (i.e., better text-related learning and similar image-related learning). Achievement findings suggest that the optimal note-taking medium depends on the nature of the lecture and whether notes are reviewed. 相似文献
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目的研究暴力行为人群交感神经功能改变的特点.方法选择了46例暴力型服刑人员,调查其个人史,进行体格检查、植物神经功能检查,肾上腺素(E)、去甲肾上腺素(NE)等测定.结果87%交感神经功能亢进;73.9%NE和/或E增高,以NE增高为主.结论A型行为易产生交感神经功能亢进,进而兴奋了交感-肾上腺(髓质)系统,使E、NE分泌增高,NE增高者暴力行为也较严重. 相似文献