抗菌肽及其应用研究进展

抗菌肽是生物防御系统产生的一类对抗外源性病原体的肽类物质,具有抗细菌、真菌、霉菌、病毒、原虫、癌细胞等多种活性,具有广阔的应用前景。本文就抗菌肽的分类、理化特征、结构、作用机制、基因工程、应用前景及存在问题等方面进行了简要综述。     

生物抗菌肽研究进展

介绍抗菌肽的理化性质、分类、作用机制及其基因工程研究现状和抗菌肽药物开发前景。     

鱼类抗菌肽的研究进展

鱼类抗菌肽是鱼体天然免疫的重要组成部分,其结构和组成复杂多样.根据生化和结构特点,可将它们分为4种基本类型：具有疏水或双亲性α螺旋结构的抗菌肽、含多对二硫键并可形成β折叠结构的抗菌肽、组蛋白样抗菌肽和具有糖基化修饰的抗菌肽.鱼类抗菌肽多以前肽原的形式合成,通过酶解切除信号肽和羧基端酸性片段后形成有活性的成熟肽.成熟肽具有很强的抑菌活性,其最小抑制浓度多在毫摩尔水平.目前,已克隆了多个鱼类抗菌肽基因,揭示了pleurocidin等基因家族的结构及其转录调控特点.鱼类抗菌肽的抗菌机制已建立了“桶-桶板”和“地毯”样两种模型,基本阐明了抗菌肽分子结构与抗菌功能间的关系.     

抗菌肽及其临床应用研究进展

抗菌肽是生物体在抵抗病原微生物的防御反应过程中产生的一类具有抗微生物活性的小分子多肽。抗菌肽是机体天然免疫系统的重要组成部分,具有广谱的抗革兰氏阳性、阴性菌活性,对真菌、某些有包膜的病毒、寄生虫以及肿瘤细胞也有抑制活性。抗菌肽具有不同于传统抗生素的独特抗菌机制,病原菌不宜对其产生耐药性,有可能成为一种新的抗生素替代品。介绍了抗菌肽的来源与分类、理化特性与生物学活性,并重点阐述其最新的临床应用进展。     

抗菌肽的设计及其应用

抗菌肽(AMP)是生物体内先天免疫系统的一个组成部分,保护机体免受致病微生物的入侵.抗菌肽具有很强的广谱抗菌活性,可抑制革兰氏阳性菌、革兰氏阴性菌、真菌和病毒的生长.为克服微生物对抗生素耐药性的问题,目前阳离子抗菌肽已被考虑作为抗生素的潜在替代品.本文将阐述抗菌肽的作用机理、选择性抗菌肽的设计及其应用.     

抗菌肽Lactoferricin生物学功能及其应用研究进展

概述了乳铁蛋白活性多肽(lactofericin)所具有的广谱抗菌、抗寄生虫、抗病毒、抗癌、抗氧化等多种生物学活性,讨论了lactnferricin的制备方法,并对lactnferricin作为饲料添加剂的应用前景作了初步探讨。     

水产动物抗菌肽的研究进展

抗菌肽广泛分布于多种生物,具有分子量小、耐热、广谱抗菌等特性。它在杀菌过程中不易产生耐药性,使其具有潜在的医药价值。本文综述了水产动物抗菌肽的结构特征、生物学活性、抗菌机制、目前克隆的基因的结构与功能,以及在免疫防御中的表达等一系列问题。     

抗菌肽抗菌机制及其应用研究进展

抗菌肽是一类小分子肽,具有广谱的抗菌活性。以往对抗菌肽抗菌机制的研究主要集中在细菌细胞膜的作用上,包含桶板模型、毯式模型,环形孔模型和凝聚模型。近年来相继发现某些抗菌肽可以作用于细菌细胞内部,与核酸物质结合,阻断DNA复制、RNA合成;影响蛋白质合成;抑制隔膜、细胞壁合成,阻碍细胞分裂;抑制胞内酶的活性。本文从胞内机制和胞外机制两个角度对抗菌肽的抗菌机制进行综述,以期阐明各类抗菌肽的作用机制,为进一步研究菌株耐药性、杀菌效果及其杀菌机制提供科学根据。     

细菌抗菌肽的研究进展及其应用

概述了抗菌肽的分类和作用机制;着重介绍了细菌抗菌肽的分类、研究近况、开发利用状况,指出其广泛的应用前景.     

抗菌肽研究进展

抗菌肽研究进展傅南雁许家喜＊（北京大学化学与分子工程学院,北京１００８７１）关键词抗菌肽两亲螺旋青霉素的发现使人们对由病原微生物感染而引发的各类疾病不再束手无策,并由此发展了大量的β－内酰胺类抗生素,对保护人类健康作出了巨大贡献。但随着上述“传统抗生...     

Design and Synthesis of Heterocyclic Conjugated Peptides as Novel Antimicrobial Agents

Antimicrobial peptides have been recognized as a novel class of antibiotics and several candidates are currently in clinical trials. In the present study, new antimicrobial compounds were synthesized by coupling quinazolinone moiety with the fragments of elastin sequences VP, GVP, VGVP and GVGVP. They were evaluated for their antibacterial activity against both gram positive and gram negative bacterial strains. We are here reporting that heterocyclic conjugated tetra peptide and penta peptide showed enhanced antibacterial activity compare to the conventional antimicrobial drugs.     

Antimicrobial Peptides and their Potential as Oral Therapeutic Agents

Dental caries (tooth decay) and periodontal diseases are the most prevalent bacterial infectious diseases of mankind, together affecting almost the entire population of the world. Both diseases are caused by oral bacteria that exist as components of a polymicrobial biofilm, known as dental plaque, on the tooth surface. The control of specific types of bacteria and/or total numbers of bacteria in dental plaque could lead to prevention or resolution of disease. Antimicrobial peptides isolated from a wide range of natural sources have been known for over 30 years yet little progress had been made in the therapeutic application of these peptides. This is due in part to the characteristics, including susceptibility to proteolysis, of the cationic amphipathic antimicrobial peptides that form the majority of peptides discovered to date. Bovine milk is a readily available source of a range of bioactive peptides. We have isolated and characterized a novel anionic antimicrobial peptide, Kappacin, from bovine milk. Antibacterial activity of the peptide is increased when it is complexed with zinc ions. We have demonstrated that a Kappacin:Zn²⁺ preparation is able to suppress the growth of oral cariogenic bacteria in a biofilm. The Kappacin:Zn²⁺ antibacterial complex may have potential as an additive to oral care products and other delivery vehicles for the control of oral disease.     

海洋无脊椎动物抗菌肽研究进展及其在食品保鲜中的应用

海洋无脊椎动物抗菌肽抑菌广谱,稳定性高,且对生物体本身无害,其应用日益引起大量研究者的关注。综述了抗菌肽的几种类型、抑菌机理,介绍了海洋无脊椎动物抗菌肽研究进展、存在的问题并分析其在食品保鲜中的应用前景。     

昆虫抗菌肽研究和应用现状

昆虫在受到刺激或感染之后,在其血淋巴中会产生一种抗菌类物质,称抗菌肽。抗菌肽具有分子小、稳定性好、广谱抗菌、无毒副作用等特点,在农业、医药、食品等领域有广泛的应用前景。简要综述了昆虫抗菌肽的基础研究和应用现状。     

Human Antimicrobial Peptides: Defensins, Cathelicidins and Histatins

Antimicrobial peptides, which have been isolated from many bacteria, fungi, plants, invertebrates and vertebrates, are an important component of the natural defenses of most living organisms. The isolated peptides are very heterogeneous in length, sequence and structure, but most of them are small, cationic and amphipathic. These peptides exhibit broad-spectrum activity against Gram-positive and Gram-negative bacteria, yeasts, fungi and enveloped viruses. A wide variety of human proteins and peptides also have antimicrobial activity and play important roles in innate immunity. In this review we discuss three important groups of human antimicrobial peptides. The defensins are cationic non-glycosylated peptides containing six cysteine residues that form three intramolecular disulfide bridges, resulting in a triple-stranded β-sheet structure. In humans, two classes of defensins can be found: α-defensins and β-defensins. The defensin-related HE2 isoforms will also be discussed. The second group is the family of histatins, which are small, cationic, histidine-rich peptides present in human saliva. Histatins adopt a random coil conformation in aqueous solvents and form α-helices in non-aqueous solvents. The third group comprises only one antimicrobial peptide, the cathelicidin LL−37. This peptide is derived proteolytically from the C-terminal end of the human CAP18 protein. Just like the histatins, it adopts a largely random coil conformation in a hydrophilic environment, and forms an α-helical structure in a hydrophobic environment.     

Effects of the antimicrobial peptide cecropin AD on performance and intestinal health in weaned piglets challenged with Escherichia coli

This study was conducted to determine the effects of the antimicrobial peptide cecropin on performance and intestinal health in piglets. Newly weaned barrows were randomly assigned to one of three treatments (n=8), including a corn-soybean basal diet or similar diets supplemented with antibiotics (100 mg/kg kitasamycin plus 800 mg/kg colistin sulfate) or 400 mg/kg cecropin AD. On day 13, all piglets were orally challenged with 10(9)CFU/mL of Escherichia coli K88. On day 19, all piglets were euthanized and sampled. Before challenge, piglets fed antibiotics had greater weight gain, feed efficiency, nitrogen and energy retention than the control (P<0.05). E. coli challenge decreased weight gain, feed intake and feed efficiency for the control piglets (P<0.05) but not for the antibiotic or cecropin AD treated piglets. The incidence of diarrhea post-challenge in the antibiotic and cecropin AD treatments decreased compared with the control piglets. The total viable counts of cecal E. coli were lower while the Lactobacilli counts were higher in the antibiotic and cecropin AD treatments compared with the control (P<0.05). Cecropin AD treatment decreased total aerobes while increasing total anaerobes in the ileum (P<0.05). A higher villus height to crypt depth ratio in the jejunum and ileum as well as a deeper crypt depth in the jejunum and higher villus height in the ileum were observed in piglets fed antibiotics or cecropin AD compared with control piglets (P<0.05). Piglets fed the control diet had lower levels of secretory IgA in their jejunum and lower serum IgA, IgG, interleukin-1β and interleukin-6 compared with the other treatments (P<0.05). Overall, these data suggest that cecropin AD enhances pig performance through increasing immune status and nitrogen and energy retention as well as reducing intestinal pathogens in weaned piglets.     

Complement Activation Products C3a and C4a as Endogenous Antimicrobial Peptides

All vertebrate species are constantly challenged by infectious agents and pathogens. In order to fight these infectious agents the human host has developed a sophisticated and powerful immune defense. The complement system, which represents the first defense line of innate immunity is activated immediately, within seconds. The activated immune system recognizes and damages an invading microbe, coordinates the host immune response and further orchestrates the adaptive immune response. Activation of the complement system leads to a rapid and amplified response which includes the generation of small peptides like C3a and C4a that display antimicrobial, anti-fungal and anaphylactic activity. Here we report how these antimicrobial peptides are generated during the immune response and summarize the functional mechanisms of these intrinsically generated anti microbial peptides.