共查询到19条相似文献,搜索用时 62 毫秒
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阳离子抗菌肽的研究进展 总被引:20,自引:0,他引:20
阳离子抗菌肽是一类具抗微生物活性的小分子多肽,按结构特征可分为α-螺旋肽和β-折叠肽,不同来源或同一抗菌肽的不同结构形式生物活性差别较大,部分抗菌肽之间或抗菌肽与抗生素之间存在协同作用,特别是最近发现一些抗菌肽具有抗内毒素活性。阳离子抗菌肽的结构特征是其发挥作用的重要基础,α-螺旋肽通过其两亲性的α-螺旋上的正电茶与细菌细胞膜磷脂分子的负电荷之间的静电吸引而结合在细菌膜上,并借助于疏水段分子中连接结构的柔性插入到细胞膜中,最终通过膜内分子间的相互位移使抗菌肽分子相互聚集在一起形成离子通道,使细菌失去膜势,不能保持正常的渗透压而死亡。一般认为β-折叠肽也是和细胞膜结合后,结构发生变化而发挥作用。抗菌肽和细胞膜结合及形成离子通道受多种因素的影响,如阳离子抗菌肽的结构、浓度,环境 pH、温度,介质的离子强度。阳离子抗菌肽杀菌力强,抗菌谱广,不良反应少,因此在食品、农业,特别是在医药领域都有很好的应用前景,极可能发展成为一类全新的抗生素。 相似文献
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抗菌肽是具有天然抗菌活性的一类生物多肽。海洋无脊椎动物和鱼类是海洋生物多样性的代表,也是发现结构、功能具有独特性的新型抗菌肽的源泉。目前,已从海洋无脊椎动物,包括刺胞动物、软体动物、环节动物、甲壳动物、棘皮动物和原索动物以及脊椎动物鱼类分离出多种抗菌肽。本文章对海洋无脊椎动物和鱼类中抗菌肽的研究进展、作用机理和研究趋势作了简要概述。 相似文献
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摘要:目的 探讨富含脯氨酸蛋白11(PRR11)在胆囊癌组织中的表达及意义。方法 用免疫组织化学染色SP
法测定58例人胆囊癌、癌旁组织和49例慢性胆囊炎组织中PRR11蛋白的表达情况,统计分析其与胆囊癌组织学类
型、胆囊癌Nevein分期、淋巴结转移、组织分化等临床病理参数的关系。结果 PRR11蛋白在胆囊癌中的阳性表达
率为 55.2%(32/58),远高于其在癌旁组织 25.9%(15/58)和慢性胆囊炎 4.1%(2/49)中的阳性表达率(均 P < 0.01)。
RR11的表达在不同Nevein分期、组织分化程度和有无淋巴结转移分组中比较,差异有统计学意义(均P < 0.01),而
不同年龄、性别及组织学分型分组比较,差异无统计学意义。结论 PRR11蛋白在胆囊癌组织中高表达,而在癌旁
组织和慢性胆囊炎组织中微弱表达或不表达,提示其可能参与胆囊癌的发生、侵袭及转移的过程。 相似文献
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综述了各种结构类型的具有抗肿瘤活性的抗菌肽(抗癌肽),并对其具体的作用机制、结构改造、联合应用及未来发展趋势进行了论述。 相似文献
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抗菌肽,是自然界中存在于众多生物体内对抗外源真菌、细菌及病毒等微生物入侵的天然防御系统主要活性成分.抗菌肽表现出较广的抗菌谱,抗菌机制独特且复杂,不易产生耐药性,被认为是目前多重耐药菌的较佳药物.许多非人源的抗菌肽有免疫原性、溶血反应及半衰期短等问题.研究工作者在原有的抗菌肽基础上,通过不同的修饰,使得抗菌肽的活性提高、毒性降低、制备工艺简化等.同时也有科研工作者,不断进行抗菌肽作用机制的研究,以期为抗菌肽的发现及设计提供更多的可行性借鉴.本文就近三年来,抗菌肽修饰及作用机制的研究进行综述. 相似文献
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Recent updates of marine antimicrobial peptides 总被引:1,自引:0,他引:1
Mohammad H. Semreen Mohammed I. El-Gamal Shifaa Abdin Hajar Alkhazraji Leena Kamal Saba Hammad Faten El-Awady Dima Waleed Layal Kourbaj 《Saudi Pharmaceutical Journal》2018,26(3):396-409
Antimicrobial peptides are group of proteins showing broad-spectrum antimicrobial activity that have been known to be powerful agents against a variety of pathogens. This class of compounds contributed to solving the microbial resistance dilemma that limited the use of many potent antimicrobial agents. The marine environment is known to be one of the richest sources for antimicrobial peptides, yet this environment is not fully explored. Hence, the scientific research attention should be directed toward the marine ecosystem as enormous amount of useful discoveries could be brought to the forefront. In the current article, the marine antimicrobial peptides reported from mid 2012 to 2017 have been reviewed. 相似文献
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Chen Y Vasil AI Rehaume L Mant CT Burns JL Vasil ML Hancock RE Hodges RS 《Chemical biology & drug design》2006,67(2):162-173
In our previous study (Chen et al. J Biol Chem 2005, 280:12316-12329), we utilized an alpha-helical antimicrobial peptide V(681) as the framework to study the effects of peptide hydrophobicity, amphipathicity, and helicity on biologic activities where we obtained several V(681) analogs with dramatic improvement in peptide therapeutic indices against gram-negative and gram-positive bacteria. In the present study, the D-enantiomers of three peptides--V(681), V13A(D) and V13K(L) were synthesized to compare biophysical and biologic properties with their enantiomeric isomers. Each D-enantiomer was shown by circular dichroism spectroscopy to be a mirror image of the corresponding L-isomer in benign conditions and in the presence of 50% trifluoroethanol. L- and D-enantiomers exhibited equivalent antimicrobial activities against a diverse group of Pseudomonas aeruginosa clinical isolates, various gram-negative and gram-positive bacteria and a fungus. In addition, L- and D-enantiomeric peptides were equally active in their ability to lyse human red blood cells. The similar activity of L- and D-enantiomeric peptides on prokaryotic or eukaryotic cell membranes suggests that there are no chiral receptors and the cell membrane is the sole target for these peptides. Peptide D-V13K(D) showed significant improvements in the therapeutic indices compared with the parent peptide V(681) by 53-fold against P. aeruginosa strains, 80-fold against gram-negative bacteria, 69-fold against gram-positive bacteria, and 33-fold against Candida albicans. The excellent stability of D-enantiomers to trypsin digestion (no proteolysis by trypsin) compared with the rapid breakdown of the L-enantiomers highlights the advantage of the D-enantiomers and their potential as clinical therapeutics. 相似文献
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LINGXIU ZHONG REBECCA J. PUTNAM W. CURTIS JOHNSON A. GURURAJ RAO 《Chemical biology & drug design》1995,45(4):337-347
A large proportion of antimicrobial peptides share a common structural feature that is critical to their antimicrobial activity, i.e. amphipathic α-helices. The amphipathy of a polypeptide chain can be quantitated through the value of the hydrophobic moment. Generally, antimicrobial peptides are characterized by high hydrophobic moment and low hydrophobicity values. Using these criteria we have identified two short segments that possess hydrophobic moment properties associated with known antimicrobial peptides. Using in vitro assays the segment derived from the protein perforin displays no antifungal or antibacterial activity and, while showing no α-helicity in buffer or liposomes, exhibits a modest degree of α-helical structure in the presence of the a-helical inducer, 2,2,2-trifluoroethanol. However, rational modifications result in a derivative which assumes an α-helical conformation in the presence of liposomes, exhibits potent antifungal activity against plant fungal pathogens, has significant antibacterial activity, effects leakage of a fluorescent dye from acidic liposomes and is devoid of hemolytic activity. Results are also presented for a segment derived from the human immunodeficiency virus envelope protein. We suggest that the identification of putative amphipathic structures in proteins may provide a useful starting strategy in the design and synthesis of antimicrobial peptides. 相似文献