有机酸抑菌分子机理研究进展

有机酸作为一种可有效抑制畜禽体内病原微生物增殖的饲用生长促进剂,正日益受到关注。不同有机酸抑菌机理不尽相同。笔者综述了有机酸分子水平抑菌机理研究的最新进展,包括基于能量竞争、透化细菌外膜、提高胞内渗透压、抑制生物大分子合成、诱导宿主产生抗菌肽等5种作用机制;认为细菌胞内酸根离子的聚集是有机酸抑菌作用的重要决定因素,细菌胞内外pH梯度及胞外酸根离子浓度又是影响胞内酸根离子聚集的主要因素。  

生姜对小鼠血清溶菌酶活性的影响

为观察生姜对小鼠血清溶菌酶活性的影响，将40只小鼠随机分为4组，每组10只，实验组灌服生姜匀浆液，对照组灌服蒸馏水，4组小鼠均饲喂正常饲料，20d检测小鼠血清中溶菌酶含量。结果表明，灌服生姜组小鼠血清溶菌酶含量明显高于对照组。实验证实，提高血清溶菌酶活性是生姜抗菌的机制之一。  

抗菌脂肽Surfactin的抗菌活性及应用

Surfactin是枯草芽孢杆菌属不同菌株代谢产生的一种抗菌脂肽,不仅能抑制多种革兰氏阳性菌、革兰氏阴性菌和真菌等病原菌,而且还具有抗病毒、抗支原体、抗原虫等活性,是潜在的抗生素理想替代品之一. 本文对抗菌脂肽Surfactin的结构、理化性质、抗菌机制及应用研究进展进行了综述,为Surfactin的进一步研究和应用提供参考.  

抗菌肽的研究及畜牧业中的应用

抗菌肽（Antimicrobial peptides）广泛存在于多种动植物的体内,是天然免疫系统的重要组成部分,具有高效广谱抗菌性,与抗生素具有不同的抗菌机理,对真核细胞几乎没有作用,仅作用于原核细胞,同时不易使病原菌产生抗药性,且对伤口的愈合和癌症有一定的作用,很有可能成为新一代的抗菌药物。本文结合当今抗菌肽的研究现状和发展前景,对抗菌肽的分类、抗菌机制、应用状况进行了综述。  

截短侧耳素类抗生素的研究进展

截短侧耳素(pleuromutilin,化合物1)是由担子菌产生的一种三环二萜类兽用抗生素,对革兰阳性菌和支原体有强抗菌活性[1]。自1950年发现以来,以截短侧耳素为先导化合物,已成功开发出泰妙菌素(tiamulin,化合物2)和沃尼妙林(valnemulin,化  

乳酸菌Ⅱa类细菌素抗菌机制的研究

从细胞及分子水平上就乳酸菌Ⅱa类细菌素抗菌机制及其在动物体内的抗菌作用研究作一综述。  

几种鱼类抗菌肽的研究进展

抗菌肽以其优越的特点,如具有广谱抗菌活性,选择性杀灭病原体,水溶性好和耐热性能高等,在渔业养殖上有取代抗生素的趋势。文章综述几种鱼类抗菌肽的种类及其生物学活性、抗菌机制、抗菌肽基因的表达调控以及一些分子生物手段在此方面的研究应用,并做出展望。  

新型高效安全的抗菌制剂——抗菌肽

抗菌肽是一种具有广谱抗菌性能的多肽，在畜牧业上具有重要的潜在应用前景。作者综述了抗菌肽的生物学特性、功能和抗菌机制，以及新发现的抗菌肽，并对其应用研究及前景进行阐述。  

Effect of Antimicrobial Peptide NZ2114 on Cell Membrane,Genome and Antimicrobial Resistance of Staphylococcus aureus Isolated from Bovine Mastitis Milk

The aim of this study was to elucidate antibacterial mechanism of the fungal defense Plectasin derived peptide NZ2114 against Staphylococcus aureus (S.aureus) that caused cow mastitis and its effect on inhibiting drug resistance of S.aureus in vitro.16S rRNA gene identification and disc diffusion method were used to identify the pathogenic bacteria of 55 mastitis milk samples and test their drug resistance,microdilution method was used for determining the antimicrobial activity of NZ2114 to S.aureus.The effect of NZ2114 on S.aureus cell membrane integrity and cell morphology were observed by flow cytometry and scanning electron microscope.The methods of gel retardation and circular dichroism spectrum were used to analyze the effect of NZ2114 on S.aureus genome DNA.The effect of NZ2114 on the drug resistance S.aureus was studied by incubating NZ2114 with S.aureus.The effect of NZ2114 on the drug resistance genes of S.aureus was further identified by PCR.The results showed that 10 strains of S.aureus were obtained,which were resistant to 9 antibiotics such as penicillin,and 50% of them were multidrug resistant.NZ2114 showed strong inhibitory activity against 10 strains of S.aureus,and the minimum inhibitory concentrations (MIC) were 0.5 to 1.0 μg/mL.NZ2114 could cause micromorphological change of S.aureus S7,including cell surface shrinkage,cell contents leakage,and cell lysis and propidine iodide (PI) cell membrane penetration rate was up to 5%.Additionally,NZ2114 could bind to S.aureus S7 genomic DNA and change its structure.S.aureus and 1/4×MIC NZ2114 were incubated together for 12 h,the result demonstrated that except amoxicillin and sulfanilamide,the resistance to other antibiotics of S.aureus had decreased to different extent (10% to 40%) and the elimination rate of NZ2114 to blaZ and braRS genes were 28.57% (2/7) and 22.22% (2/9),respectively.The above results proved that NZ2114 had strong inhibited activity against multidrug resistant S.aureus,and its mechanism of interfering with the membrane and intracellular DNA,which laid the cytological foundation for its low drug resistant bactericidal mechanism.At the same time,NZ2114 had elimination effect on the drug resistance and related drug resistant genes of S.aureus.Thus,NZ2114 was a promising antibiotic alternative for treatment of cow mastitis caused by S.aureus.  

浅谈抗菌肽的抗菌活性

抗菌肽(ABP)又称为抗微生物肽(AMP)、宿主防御肽(HDPs)、肽抗生素,是动物免疫防御系统在外界条件刺激下,产生的一类对抗外源性病原体致病作用的具有免疫活性的多肽,是动物非特异性免疫防御系统的一个重要组成部分。依据其物种来源的不同,被分别命名为防御素、蛙皮素和蜂毒素等。抗菌肽有着分子量小、活性强、