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1.
采用比色法分析比较了金花茶多糖与蓖麻凝集素、伴刀豆凝集素等凝集素的凝集反应特性.结果显示,不同凝集素均能与金花茶多糖发生凝集反应,但凝集反应程度有明显差异.特异结合糖残基为半乳糖的蓖麻凝集素与金花茶多糖的凝集反应效果最显著,而特异结合糖残基同样为半乳糖或其衍生物的海红豆凝集素、欧卫矛凝集素、怀槐凝集素和花生凝集素的凝集反应程度则比较弱.当金花茶多糖浓度上升至6.59 mg/mL时,蓖麻凝集素的凝集反应是其他凝集素的6~10倍.另一方面,特异结合糖残基为甘露糖的伴刀豆凝集素与金花茶多糖虽然有类似的凝集反应特征,但是其凝集反应程度明显弱于蓖麻凝集素.从以上结果推测,凝集素的分子形态对金花茶多糖的凝集反应有显著影响.  相似文献   
2.
植物凝集素对桃蚜生长发育的影响   总被引:10,自引:0,他引:10  
通过实验 ,研究了来自三种不同植物的植物凝集素 (ConA、STA和WGA)对桃蚜生长发育的影响 ,发现这三种植物凝集素对桃蚜均有一定的拒食性 ,并且对桃蚜的蜜露分泌量、平均相对生长速率以及存活率均有一定的影响 ,其中以STA的影响最为显著 ,WGA次之 ,ConA为最弱  相似文献   
3.
Due to their high biodiversity and adaptation to a mutable and challenging environment, aquatic lophotrochozoan animals are regarded as a virtually unlimited source of bioactive molecules. Among these, lectins, i.e., proteins with remarkable carbohydrate-recognition properties involved in immunity, reproduction, self/nonself recognition and several other biological processes, are particularly attractive targets for biotechnological research. To date, lectin research in the Lophotrochozoa has been restricted to the most widespread phyla, which are the usual targets of comparative immunology studies, such as Mollusca and Annelida. Here we provide the first overview of the repertoire of the secretory lectin-like molecules encoded by the genomes of six target rotifer species: Brachionus calyciflorus, Brachionus plicatilis, Proales similis (class Monogononta), Adineta ricciae, Didymodactylos carnosus and Rotaria sordida (class Bdelloidea). Overall, while rotifer secretory lectins display a high molecular diversity and belong to nine different structural classes, their total number is significantly lower than for other groups of lophotrochozoans, with no evidence of lineage-specific expansion events. Considering the high evolutionary divergence between rotifers and the other major sister phyla, their widespread distribution in aquatic environments and the ease of their collection and rearing in laboratory conditions, these organisms may represent interesting targets for glycobiological studies, which may allow the identification of novel carbohydrate-binding proteins with peculiar biological properties.  相似文献   
4.
The purpose of this work is to perform a detailed study of carbohydrate specificity of the new extracellular bacilli lectins which is considered to determine mechanisms of the lectins action. Sources of lectins were bacterial strains from Ukrainian collection of microorganisms. The optimized protocol of bacilli lectins isolation and purification included precipitation with ammonium sulfate with subsequent gel filtration chromatography on Sepharose CL-6B. Hemagglutinating activity of bacilli lectins and their fine carbohydrate specificity to sialic acids and their derivatives as well as sialic asid-containing and asialic glycoconjugates were studied. The ability of extracellular bacilli lectins to discriminate a- and 13-conformation of carbohydrate molecule and the type of connection between the monomers was determined. Studied lectins showed the most affinity to glycoconjugates containing both types of sialic acids (N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (NeuGc)) and it is supposed to be a basis of their diagnostic and analytical potential.  相似文献   
5.
We histologically examined lectin binding patterns in the olfactory bulb of mallard ducks (Anas platyrhynchos) using 21 biotinylated lectins. Positive staining for the N‐acetylglucosamine‐specific lectins (Bandeiraea simplicifolia II, Datura stramonium, Lycopersicon esculentum, Solanum tuberosum, Triticum vulgare), galactose or N‐acetylgalactosamine‐specific lectins (Artocarpus intergrifolia, Phaseolus vulgaris erythroagglutinin, Phaseolus vulgaris leucoagglutinin, Ricus communis) and the mannose‐specific lectins (Lens culinaris and Pisum sativum) was observed in the olfactory nerve and glomerular layers. Canavalia ensiformis staining showed a similar pattern to that obtained with the lectins and there was also faint staining in the mitral cells. Olfactory nerve axons terminate in the glomeruli, where they make excitatory synapses with the dendrites of mitral cells. This finding indicates that glycoconjugates that bind Canavalia ensiformis play an important role in formation of glomeruli. No positive staining for the other lectins was seen in the olfactory bulb. Based on these results, we conclude that cell surface sugar moieties of the olfactory bulb in mallard ducks express N‐acetylglucosamine and mannose residues rather than N‐acetylgalactosamine residues. The carbohydrate composition of mallard duck olfactory bulb differed from that of other vertebrates found in previous studies.  相似文献   
6.
C型凝集素(C-type lectin)是一类能与糖类结合的非抗体的蛋白质或糖蛋白家族,为了研究C型凝集素基因在日本沼虾组织分布、细胞定位和细菌感染过程中的表达情况,本研究应用cDNA末端快速克隆(rapid-amplification of cDNA ends,RACE)技术首次克隆了日本沼虾C型凝集素结构域家族3基因(MnLec3)的全长序列,通过实时荧光定量PCR(qRT-PCR)分析MnLec3基因在不同组织、细菌感染后不同时间的表达水平,Western blot和免疫荧光分别分析蛋白的表达水平和细胞定位。结果显示,MnLec3基因cDNA全长1 357 bp,包括125 bp的5′末端非翻译区(UTR)、1 026 bp的开放阅读框(ORF)和206 bp的3′UTR,其中开放阅读框编码341个氨基酸。氨基酸序列比对显示,日本沼虾MnLec3基因含有保守钙结合点(Met 1-Glu17)和糖识别结构域(CRD)。同源性分析结果显示,MnLec3与罗氏沼虾C型凝集素3相似度较高;邻接法(Neighbor-Joining,NJ)进化树分析结果显示,MnLec3与其他甲壳动物C型凝集素聚为一支。通过构建原核表达载体获得体外重组蛋白rMnLec3,并将纯化重组蛋白免疫大鼠获得抗血清,免疫荧光结果显示,绿色荧光信号主要在肝胰腺细胞核中表达。qRT-PCR结果显示,MnLec3在日本沼虾所检测组织中均表达,其中肝胰腺中表达量最高,血细胞次之;与对照组相比,在嗜水气单胞菌刺激12~48 h时MnLec3表达量显著升高,48 h表达量最高,Western blot分析结果显示,MnLec3蛋白表达丰度与基因表达模式基本相似,提示克隆得到的MnLec3参与日本沼虾抵御细菌入侵的免疫过程。  相似文献   
7.
Jacalin-related lectins (JRLs) are widely distributed carbohydrate-binding proteins in the plant kingdom, which play key roles in development and pathogen defense. In this study, we profiled evolutionary trajectory of JRLs family in 30 plant species and identified domain diversification and recombination leading to different responsive patterns of JRLs in rice during defense against rice blast. All of 30 plant species analyzed in our study have two types of JRLs by containing either a single jacalin or repeated jacalin domains, while chimeric jacalins exist in more than half of the species, especially in the Poaceae family. Moreover, Poaceae species have evolved two types of unique chimeric JRLs by fusing the jacalin domain(s) with dirigent or NB_ARC domain, some of which positively regulate plant immunity. Seven Poaceae-specific JRLs are found in the rice genome. We further found expression of rice JRLs, including four Poaceae-specific JRLs, are induced by Magnaporthe oryzae infections at either early or late infection stages. Overall, the results present the evolutionary trajectory of JRLs in plant and highlight essential roles of Poaceae specific JRLs against pathogen attacks in rice.  相似文献   
8.
The protein expression profiling in clam haemocytes and plasma in response to Perkinsus olseni was addressed. Adult Manila clams from a P. olseni‐free bed were experimentally challenged with parasite zoospores to analyse immune response. In another experiment, the effects of longer term infection were assessed in adult clams collected from a P. olseni‐affected bed, by comparing moderate to very heavily infected clams with non‐infected ones. Haemocyte and plasma proteins were separated by two‐dimensional electrophoresis; spot patterns were qualitatively compared between treatments within each experiment and the spots indicating differential protein expression associated with P. olseni challenge or with field infection were processed for protein identification. Fifteen clam proteins (four in haemocytes and eleven in plasma) of which expression was markedly affected by P. olseni were identified. Some of the identified proteins have a well‐known role in clam immune response against the parasite, such as lysozyme and lectins. Rho GTPase‐activating protein 6 could be a marker of resistance against P. olseni, which should be further studied.  相似文献   
9.
The development of the epidermis of octopus, Octopus vulgaris, throughout its life cycle was studied by conventional staining and histochemical techniques using lectins. The mantle, the arm and the two parts of the suckers: the infundibulum and the acetabulum were analysed independently. With the exception of the suckers, the general morphology of the epidermis does not vary from the first days post-hatching to adulthood. In general terms, histochemical techniques do not indicate changes in the composition of glycoconjugates of the epidermis main cells, epithelial and secretory cells. The epithelial cells of the mantle and arm show positivity for mannose (ConA+) in their apical portions, indicating the presence of n-glycoproteins that, among other things, provide lubrication to the surface of the body. In the suckers, the apical surface of the infundibulum contains sulphated glycosaminoglycans of the N-acetylglucosamine type that provide adhesive properties. In addition to observing three types of mucocytes, m1 and m2 are characteristic of the mantle and arm, and m3 is found in the suckers. The paralarva epidermis is characterised by the presence of Kölliker's organs whose exact function is unknown. In this study, the absence of staining with alcian blue/periodic acid–Schiff(AB/PAS) prevents the possibility of attributing a secretory function. Nevertheless, the linkage of three lectins (WGA, LEL and GSL-I) in the fascicle of the organ suggests the presence of proteoglycans rich in N-acetylglucosamine that would mainly have a structural role.  相似文献   
10.
Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds.  相似文献   
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