In recent years , for the irrational use of antibiotics produces resistant strains and other reasons , bacterial resistance is more and more serious . human are trying to solve the problem from different ways , including the study of antimicrobial peptides . defensin is one of the most important of antimicrobial peptides 防御素( defensin )是抗菌肽中较为重要的一种，是一种生物体产生的具有强大的抗菌功能的阳离子小分子多肽，主要来源于皮肤、呼吸道等的上皮组织，是正常机体抵抗外界病原微生物入侵的重要防线。
Antibacteral peptide ( abp ) existing in the biosphere with the biotic activity is a kind of little peptide and has the action of antibacteria commonly and even can resist some protozoa , virus and tumour cells . the antibacteral peptide has become one of the hot spots of foreign and domestic scholars " investigavitions who gave more and more favors to it as its no ill effect 抗菌肽( antibacteralpeptides ， abp ) ，是生物界中广泛存在的一类生物活性小肽，一般具有抗细菌或真菌作用，有些还具有抗原虫、病毒或肿瘤细胞的功能，且无毒副作用，倍受国内外学者的青睐，已成为国内外学者的研究热点。
Construction of plant binary expression vector peasp in consideration of the different cell membrane disruption mechanism of plant defensin and cema , plant binary expression vector peasp were constructed . simultaneous expression of cema and afp may synergistically inhibit the growth of phytopathogens that are the main cause agent of agricultural loss 构建了双价抗菌肽基因植物表达载体peasp鉴于植物防御素与cema的空间结构、作用机制有所不同，两者在植物中的同时表达，有可能对病源真菌有协同抑制作用，构建了双价植物表达载体peasp 。
They inhibits the growth of fungi ( filamentous fungi especially ) while are non - toxic to plant cells . the main results were as follows : 1 . obtaining of spcema ( signal peptide modified cema ) spcema ( 187bp ) was amplified with two long complementary primers ( p2 and p3 ) and two primers ( pl and p4 ) containing restriction enzyme recognition site 带信号肽cema基因的pcr合成以两条部分重叠长链引物p _ 2和p _ 3延伸产物为模板， p _ 1和p _ 4为正、反引物进行pcr扩增，获得了改造的抗菌肽基因spcema ( 187bp ) 。
Construction and expression of tandem multi - copy gene edcoding ca ( 1 - 8 ) me ( 1 - 10 ) hybrid fused acidic peptide to improve antimicrobial peptide ' s expression , a novel mass - production method is proposed . it is based on the neutralization of the positive charges of antimicrobial peptide by fusing to an acidic peptide to avoid the lethal effect of the expressed peptide on the host cells 为提高抗菌肽的表达，设计在抗菌肽基因的n端融合一段编码酸性短肽的片段作为对抗菌肽前体的模拟，以减轻表达产物对宿主的毒性；同时通过含有酶切位点的接头将该融合肽基因以同向串连的方式连接成多拷贝基因。
After careful studying their relative importance to immune response and the possibility of the match , seventeen sequences of interest were selected for further experiment , including estss analogous to 11 . 5kd antibacterial peptide , lysozyme , serine protease and its inhibitor , lectin , antifreeze protein , et al . primers designed according to the sequences were used to amplify the corresponding estss from both blood and cephalothorax cdna library 在仔细分析了它们在免疫系统中的重要性和在对虾中出现的可能性之后，从中选出了17条可能编码抗菌肽，溶菌酶，凝集素、丝氨酸蛋白酶及其抑制剂，抗冻蛋白等蛋白质的序列，以此为依据设计引物，在中国对虾的血液和头胸部cdna文库中扩增相应的序列。
2 ) basis of upon studies , we have also designed and sythesized the mutation ii of the cmiv that been greatly changed in the 3 " of the gene comparing with nature cmiv : the ht gf3 ( the third loop region of htgf2 specifically binding to egfr receptor ) was fused to 3 " of gene of cmiv through a flexible linker . the gene of the mutation ii of cmiv was sequenced and clonged to the vector of ptxfus to fuse to the 3 " of gene of thioredoxin 二、在以上研究的基础上，对cmiv抗菌肽的c端进行较大的改造，即将与肿瘤细胞过度表达的表皮生长因子受体( egfr )具有高亲和性的因子多肽tgf _ 3通过疏水柔性接头连接在抗菌肽cmiv的c端，设计完整的基因，并在大肠杆菌中利用ptxfus表达载体与硫氧还蛋白进行可溶性融合蛋白表达。
