The Exploitation of Nematode-Responsive Plant Genes in Novel Nematode Control Methods     

Godelieve Gheysen  Walter Van der Eycken  Nathalie Barthels  Mansour Karimi  Marc Van Montagu 《Pest management science》1996,47(1):95-101

The molecular interactions between plants and sedentary nematodes are undergoing intense study, not only for reasons of fundamental research but also for the potential benefits to agriculture. The present technology allows the transformation of an increasing number of crop plants, providing new ways to introduce resistance against plant-parasitic nematodes. The ability of sedentary nematodes to induce specialized feeding sites in plant roots is one of the most fascinating aspects of this host–parasite interaction. Molecular approaches have been initiated to identify and characterize plant genes altered in expression after infection by sedentary nematodes. The results obtained indicate that many genes indeed become up-regulated upon nematode infection. Surprisingly, several so-called constitutive promoters that are normally used to achieve high expression in plant cells are completely ‘silenced’ in the feeding sites within days after nematode infection. Generally, there are two options available for the genetic engineering of nematode resistance: the synthesis of anti-nematode proteins or the localized production of a cytotoxic protein that interferes with the development of feeding cells. Nematode-induced promoters are very useful for the production by plants of sufficiently high levels of anti-nematode proteins at feeding sites. Alternatively, interfering with feeding-cell development is somewhat similar to the hypersensitive response evoked by nematodes in a naturally resistant plant. Here, destruction of specific plant cells can be achieved by the localized expression of a cytotoxin such as barnase, a potent ribonuclease. This approach, however, calls for a highly specific ‘non-leaky’ promoter, which is active only in the feeding cells. Another possibility is to use a two-component system, where the leakiness of the promoter in other tissues is counterbalanced by the constitutive expression of a neutralizing gene.  相似文献   

Purification and characterization of two anionic trypsins from the hepatopancreas of carp   总被引：8，自引：0，他引：8  

Min-Jie Cao  Kiyoshi Osatomi  Miho Suzuki  Kenji Hara  Katsuyasu Tachibana and  Tadashi Ishihara 《Fisheries Science》2000,66(6):1172-1179

SUMMARY: Two trypsins, designated as trypsin A and trypsin B, have been purified from the hepatopancreas of carp. The purification procedures consisted of ammonium sulfate fractionation, and chromatographies on DEAE-Sephacel, Ultrogel AcA54 and Q-Sepharose. Trypsin A was purified to homogeneity with the molecular mass of approximately 28 kDa, while trypsin B gave two close bands of 28.5 kDa and 28 kDa on sodium dodecylsulfate polyacrylamide gel electrophoresis both under reducing and non-reducing conditions. On native-PAGE, both trypsin A and trypsin B showed a single band. Trypsin A and trypsin B revealed optimum temperature of 40°C and 45°C, respectively, and shared the same optimum pH 9.0 using Boc-Phe-Ser-Arg-MCA as substrate. Both enzymes were effectively inhibited by trypsin inhibitors and their susceptibilities were similar. The NH₂-terminal amino acid sequences of trypsin A and trypsin B were determined to 37th and 40th amino acid residue, respectively. Their sequences were very homologous, but not identical to that of a trypsin-type serine proteinase from carp muscle and these of other trypsins. Immunoblotting test using the antibody raised against trypsin A cross-reacted with trypsin B positively.  相似文献   

健康家鱼肠道细菌中的嗜水气单胞菌及其胞外酶分布   总被引：8，自引：0，他引：8  

朱晓燕  汤伏生 《湖北农学院学报》1994,14(1):35-39

从健康鲢、鲤、草鱼和团头鲂肠道食物和肠壁样品中分离出１８５株细菌菌株，利用糊精一品红培养基、氧化酶测定法和淀粉酶测定法对其中的嗜水气单胞菌颁作了调查，鉴别出１９株嗜水气单胞菌、对这批菌株进一步进行了蛋白酶、ＣＭＣ酶、滤纸酶和溶血毒素调查，发现肠道嗜水气单胞菌分别产蛋白酶和ＣＭＣ酶，但均不产滤纸酶和溶血毒素。本文结果证明了肠道嗜水气单胞是肠道正常微生物鲜落之一，对鱼体有一定的有利作用。  相似文献   

鸡传染性法氏囊病病毒dsRNA的提纯与应用   总被引：5，自引：0，他引：5  

孙建和  陆苹  赵渝  李晖 《华中农业大学学报》2002,21(4):311-314

用传染性法氏囊病病毒（IBDV）攻击4周龄的非免疫鸡，以超速离心法从感染鸡法氏囊组织中分离、纯化IBDV，应用蛋白酶K消化和Trizol（异硫氰酸胍－酚－氯仿法）处理2种方法从纯化的IBDV中抽提dsRNA。通过低熔点琼脂糖割胶－酚－氯仿抽提可获得纯化的dsRNA，研究发现应用蛋白酶K消化获得的纯化RNA产量高，用其作模板进行RT－PCR可扩增IBDV基因组全长cDNA A片段和B片段、VP2基因和VP2－4－3基因。  相似文献   

蜂蛹蛋白质酶解工艺及其氨基酸口服液对小鼠的强壮作用   总被引：4，自引：0，他引：4       下载免费PDF全文

张海生  陈锦屏 《西北农林科技大学学报(自然科学版)》2007,35(1):110-115

研究了蜂蛹蛋白质的酶解工艺以及蜂蛹氨基酸口服液对小鼠的强壮作用。结果表明,1398中性蛋白酶可以对蜂蛹蛋白质进行有效水解,其最佳工艺条件为:酶浓度0.65%,料液比1∶14,在50℃下酶解4 h,游离氨基酸的生成量可达224.98 m g/g干蜂蛹。蜂蛹氨基酸口服液可以有效增加小鼠体重,提高小鼠血液红细胞数量以及血红蛋白、血清总蛋白浓度,提高受试小鼠的脏器系数。表明蜂蛹氨基酸口服液对幼年雄性小鼠具有很好的强壮作用。  相似文献   

饲料用米曲霉酸性蛋白酶研究   总被引：1，自引：0，他引：1  

曾黎明  胡春燕  徐平  黄长干 《安徽农业科学》2009,37(1):20-22

[目的]研究米曲霉酸性蛋白酶的纯化技术以及催化特性,为米曲霉酸性蛋白酶的开发和利用提供理论依据。[方法]采用丙酮沉淀,DEAE—Sephadex A-50柱层析方法分离纯化了米曲霉酸性蛋白酶,以酪蛋白为底物对其酶学性质进行了研究：[结果]结果表明：纯化倍数达到20．77;该酶最适pH值为6．0,最适温度为45℃;Fe^2＋、Mg^2＋对该蛋白酶的活性有明显的抑制作用,而Mn^2＋、Cu^2＋对该蛋白酶的活性有明显的激活作用。该蛋白酶Km=4．704mg/ml,Vmax=22．27μg／min。[结论]米曲霉蛋白酶具有很好的应用前景。  相似文献   

富含游离态异黄酮豆豉的制曲工艺优化     

高玉荣  徐国栋  李大鹏  王洪江  张丽媛  刘伟  卢旭华 《黑龙江八一农垦大学学报》2015,(2):57-61

为了制备富含游离态异黄酮的豆豉,以前期筛选出的一株高产β-葡萄糖苷酶的菌株为菌种进行制曲。在研究接种量、发酵温度、发酵时间三种单因素对豆曲中蛋白酶和β-葡萄糖苷酶的活力影响基础上,采用三元二次正交旋转组合实验设计对制曲工艺进行优化,确定了最佳的制曲工艺条件为接种量(105.4个孢子·g-1大豆)、制曲温度26.5℃、制曲时间4 d,在此条件下,β-葡萄糖苷酶酶活力为245.24 U·g-1,蛋白酶酶活力为623.17 U·g-1。  相似文献   

昆虫取食和剪叶刺激对油松针叶内部分防御物质的诱导效应     

石媛媛  冯金周  于连海  高宝嘉 《河北农业大学学报》2017,40(1)

为了研究自然条件下昆虫取食及剪叶刺激对油松诱导抗性的影响,本试验应用香草醛—盐酸法,亚硝酸钠—硝酸铝比色法以及紫外分光光度法,分析了剪叶和不同程度油松毛虫取食处理后,混交林和纯林中油松针叶内部分次生代谢物和蛋白酶抑制剂活性的动态变化。结果表明:剪叶及不同程度油松毛虫取食能够诱导缩合单宁、黄酮含量和胰蛋白酶抑制剂、胰凝乳蛋白酶抑制剂活性增加。与对照相比,胰凝乳蛋白酶抑制剂在混交林中的活性比纯林更为明显。说明剪叶及昆虫取食可诱导增加油松针叶内的缩合单宁和黄酮含量、提高胰蛋白酶抑制剂和胰凝乳蛋白酶抑制剂的活性,进而增强油松的抗虫性,林分类型可在一定程度上影响油松诱导防御物质的变化。  相似文献   

淀粉共生蛋白对淀粉水解的影响     

杨士杰  刘钟栋  占学旺 《农产品加工．学刊》2010,(10)

以小麦面粉为原料,研究了淀粉共生蛋白对淀粉酶解性质的影响。对洗淀粉过程中影响蛋白含量的条件进行了单因素试验,用SDS溶液和蛋白酶进一步除去淀粉中的蛋白质成分,然后对制得的含氮量不同的淀粉样品进行酶解。试验结果表明,蛋白酶能有效地去除淀粉共生蛋白,而淀粉共生蛋白有助于淀粉的水解。  相似文献   

Specificity of polycllonal and monoclonal antibodies for the identification of Xanthomonas campestris pv. campestris     

A. A. J. M. Franken  J. F. Zilverentant  P. M. Boonekamp  A. Schots 《European journal of plant pathology / European Foundation for Plant Pathology》1992,98(2):81-94

Polyclonal and monoclonal antibodies (PCAs and MCAs), produced to whole cells and flagellar extracts ofXanthomonas campestris pv.campestris (Xcc), respectively, were tested for specificity. In immunofluorescence microscopy (IF) the three PCAs tested, reacted at low dilutions with all Xcc strains, some other xanthomonads and non-xanthomonads. At higher dilutions most cross-reactivity with non-xanthomonad strains disappeared. However, the cross-reactivity with strains ofX. c. pv.vesicatoria (Xcv),X. c. pv.amoraciae (Xca) andX. c. pv.phaseoli var. fuscans (Xcpf) remained.Six MCA-producing cell clones viz. 20H6, 2F4, 18G12, 10C5, 17C12 and 16B5 were selected for specificity tests with an enzyme immunoassay (EIA), IF and a dot-blot immunoassay (DBI). None of the MCAs reacted with all Xcc strains in IF and EIA. In DBI, only MCAs 17C12 and 16B5 reacted with all Xcc strains. All six MCAs tested, cross-reacted in one of either tests with other pathovars ofX. campestris, such as Xcv or Xca. The MCAs were also tested in immunoblotting experiments using total bacterial extracts, cell envelope and flagellar extracts. MCAs 20H6, 2F4, 18G12 and 10C5 reacted with the lipopolysaccharide (LPS) of Xcc. MCAs 16B5 and 17C12 reacted with a 39 kilodalton and a 29 kilodalton protein, respectively.It is concluded that the PCAs and MCAs discussed in this study may be used for routine identification and differentiation of (a group of) Xcc strains. The significance of the cross-reactions with other pathovars ofX. campestris needs to be determined by testing seed lots.  相似文献