抗菌肽改良设计及抗炎作用的研究进展

抗菌肽因其具有广谱抗菌活性、不容易引起抵抗性,被认为是先天免疫系统对抗微生物感染的多功能工具。然而,天然抗菌肽存在抗菌活性低、稳定性低、溶血性高等问题,使其较难应用于临床,所以研究人员对抗菌肽进行改良设计以期获得更高抗菌活性、更低溶血活性的新型抗菌肽。另外,天然抗菌肽作为一类免疫效应因子而被发现,其表现出的抑菌、免疫调节、内毒素中和等作用,使得研究人员对抗菌肽在抗炎作用的研究表现出极大的兴趣。就抗菌肽的药物设计方法及抗炎作用机制进行综述。     

The chemistry and applications of antimicrobial polymers: a state-of-the-art review

Microbial infection remains one of the most serious complications in several areas, particularly in medical devices, drugs, health care and hygienic applications, water purification systems, hospital and dental surgery equipment, textiles, food packaging, and food storage. Antimicrobials gain interest from both academic research and industry due to their potential to provide quality and safety benefits to many materials. However, low molecular weight antimicrobial agents suffer from many disadvantages, such as toxicity to the environment and short-term antimicrobial ability. To overcome problems associated with the low molecular weight antimicrobial agents, antimicrobial functional groups can be introduced into polymer molecules. The use of antimicrobial polymers offers promise for enhancing the efficacy of some existing antimicrobial agents and minimizing the environmental problems accompanying conventional antimicrobial agents by reducing the residual toxicity of the agents, increasing their efficiency and selectivity, and prolonging the lifetime of the antimicrobial agents. Research concerning the development of antimicrobial polymers represents a great a challenge for both the academic world and industry. This article reviews the state of the art of antimicrobial polymers primarily since the last comprehensive review by one of the authors in 1996. In particular, it discusses the requirements of antimicrobial polymers, factors affecting the antimicrobial activities, methods of synthesizing antimicrobial polymers, major fields of applications, and future and perspectives in the field of antimicrobial polymers.     

Incorporation of chlorohexidin diacetate into cotton fabrics grafted with glycidyl methacrylate and cyclodextrin

Linear electron beam radiation was used to induce grafting of glycidyl methacrylate/β-cyclodextrin mixture onto cotton fabric. Chlorohexidin diacetate was incorporated to the cavities of cyclodextrin fixed on the cotton fabric to form an inclusion complex having antimicrobial activity. After incorporating chlorohexidin diacetate, the fabric was subjected to several washing cycles to examine the durability of the antimicrobial finishing. Control and grafted cotton fabrics (before and after loading with antimicrobial agent) were characterized for their antimicrobial activity against different kinds of bacteria and fungi.Grafted fabrics loaded with antimicrobial agent were found to show good antimicrobial activity in comparison with control and grafted fabrics which are not loaded with antimicrobial agent. The grafted fabrics loaded with antimicrobial agent were found also to exhibit good antimicrobial activity after five washings and this lasting antimicrobial activity can be attributed to the inclusion complex formed between chlorohexidin diacetate molecules and the cavities of cyclodextrin.     

There are abundant antimicrobial peptides in brains of two kinds of Bombina toads

It is well-known that there is a large amount of antimicrobial peptides in amphibian skins but few antimicrobial peptides are found in amphibian brains. Twenty-two and four antimicrobial peptides were purified and characterized from the brain homogenate of Bombina maxima and B. microdeladigitora, respectively. One hundred fifty-eight cDNA clones encoding 79 antimicrobial peptides were isolated from brain cDNA libraries of B. maxima and B. microdeladigitora. These antimicrobial peptides belong to two peptide groups (maximin and maximin-H). Twenty of them are identical to previously reported antimicrobial peptides (maximin 1-8, 10, 11, maximin H1, 3-5, 7, 9, 10, 12, 15, 16) from B. maxima skin secretions. Fifty-nine of them are novel antimicrobial peptides. Some of these antimicrobial peptides showed strong antimicrobial activities against tested microorganism strains including Gram-positive and -negative bacteria and fungi. The current diversity in peptide coding cDNA sequences is, to our knowledge, the most extreme yet described for any animal brains. The extreme diversity may give rise to interest to prospect the actual functions of antimicrobial peptides in amphibian brains.     

Antimicrobial peptide diversity in the skin of the torrent frog, Amolops jingdongensis

Antimicrobial peptide diversity has been found in some amphibians. The diversity of antimicrobial peptides may have resulted from the diversity of microorganisms encountered by amphibians. Peptidomics and genomics analyses were used to study antimicrobial peptide diversity in the skin secretions of the torrent frog, Amolops jingdongensis. Thirty-one antimicrobial peptides belonging to nine groups were identified in the skin secretions of this frog. Among them, there are two novel antimicrobial groups (jingdongin-1 and -2) with unique structural motifs. The other seven groups belong to known antimicrobial peptide families, namely brevinin-1, brevinin-2, odorranain-F, esculentin-2, temporin, amolopin-3, and ranacyclin. Combined with previous reports, more than 13 antimicrobial peptide groups have been identified from the genus Amolops. Most of these antimicrobial peptide groups are also found in amphibians belonging to the genus Rana or Odorrana which suggests a possible evolutionary connection among Amolops, Rana, and Odorrana. Two novel antimicrobial groups (jingdongin-1 and -2) were synthesized and their antimicrobial activities were assayed. Some of them showed strong antimicrobial abilities against microorganisms including Gram-negative and -positive bacteria, and fungi. The extreme diversity of antimicrobial peptides in the Amolops amphibians was demonstrated. In addition, several novel peptide templates were provided for antimicrobial agent design.     

细菌抗菌肽耐药机制研究进展

细菌对传统抗生素的耐药程度十分严重,寻找克服耐药性的新型抗菌药物已成为当务之急。抗菌肽(antimicrobial peptides,AMPs)是当下较有前景的抗菌药物之一。虽然通常认为,AMPs优先攻击细胞膜的特点使其不会引起广泛的耐药性,但其对特定靶标的识别能力仍为基因突变和细菌耐药性的产生提供了可能。此外,一些细菌还显示出了抵御宿主AMPs的杀伤作用并与宿主细胞共存的能力,相应的细菌防御机制也使其对治疗性AMPs产生抗性,这种交叉抗性近年来也备受关注。这些耐药现象的发现均对AMPs的开发提出了新挑战。本综述就细菌对AMPs耐药的分子机制进行了研究进展的总结,并且对治疗性AMPs与宿主防御肽交叉抗性的相关机制研究进行了归纳,以期寻求新的对抗耐药性的策略。     

疮痂链霉菌拮抗菌株BU396的分离鉴定与抗菌性质分析

【背景】随着马铃薯种植面积的扩大,疮痂病的发生也日益严重,且化学防治存在环境污染等诸多弊端,因此利用安全和高效的生物防治手段对该病害进行防治成为研究热点。【目的】对疮痂链霉菌(Streptomyces scabies)拮抗菌株进行分离、鉴定和功能基因分析,对抗菌物进行分离及抗菌特性的研究。【方法】从马铃薯疮痂病的病害土壤中分离、筛选并鉴定得到拮抗菌株,采用PCR法对菌株进行抗菌物合成基因检测。通过硫酸铵沉淀法分离得到抗菌物,进行抗菌谱和稳定性检测,并通过盆栽试验进一步验证该菌株的生防效果。【结果】通过抗菌试验筛选得到拮抗细菌BU396,根据形态学、生理生化性质和分子生物学鉴定结果,确定其为贝莱斯芽孢杆菌(Bacillus velezensis)。功能基因分析表明BU396中含有表面活性素等4种抗菌物的合成相关基因。采用硫酸铵沉淀法对其培养液上清进行分离,当硫酸铵的饱和度为75%时,抗菌物在沉淀中析出。抗菌谱试验结果显示该抗菌物对多种动植物病原菌均具有抗菌效果。稳定性试验表明该抗菌物耐热,不易被酶解,对多种金属离子不敏感,具有宽泛的pH活性范围,盆栽试验结果显示菌株BU396处理能够明显降低马铃薯疮痂病的发病率。【结论】分离并鉴定了一株对疮痂链霉菌具有显著拮抗作用的贝莱斯芽孢杆菌BU396。该菌株含有多种抗菌物合成的相关基因,其抗菌物具有广谱的抗菌活性和良好的稳定性,对马铃薯疮痂病的生防效果显著。本研究为马铃薯疮痂病的生物防治及后续抗菌物质的深入研究奠定了基础。     

肝病住院患者抗菌药物使用调查

目的了解肝病住院患者抗菌药物的使用情况。方法对62例肝病住院患者抗菌药物的应用进行调查。结果抗菌药物的使用率为25.81％;单用占75．00％;主要抗菌药物为哌拉西林、阿莫西林和头孢曲松;用药途径以静脉以及口服 静脉为主;以治疗性用药为主,预防用药在住院患者中的总使用率为4．84％;细菌标本送检率仅为6．25％。结论减少预防性用药,严格掌握抗菌药物的使用可降低抗菌药物的应用率;对于复数耐药菌感染应采取联合用药;提高细菌标本的送检率对于抗菌药物的合理应用十分重要;加强临床医师的抗菌药物知识更新和公众普及教育。     

A new effective assay to detect antimicrobial activity of filamentous fungi

The search for new antimicrobial compounds and the optimization of production methods turn the use of antimicrobial susceptibility tests a routine. The most frequently used methods are based on agar diffusion assays or on dilution in agar or broth. For filamentous fungi, the most common antimicrobial activity detection methods comprise the co-culture of two filamentous fungal strains or the use of fungal extracts to test against single-cell microorganisms. Here we report a rapid, effective and reproducible assay to detect fungal antimicrobial activity against single-cell microorganisms. This method allows an easy way of performing a fast antimicrobial screening of actively growing fungi directly against yeast. Because it makes use of an actively growing mycelium, this bioassay also provides a way for studying the production dynamics of antimicrobial compounds by filamentous fungi. The proposed assay is less time consuming and introduces the innovation of allowing the direct detection of fungal antimicrobial properties against single cell microorganisms without the prior isolation of the active substance(s). This is particularly useful when performing large screenings for fungal antimicrobial activity. With this bioassay, antimicrobial activity of Hypholoma fasciculare against yeast species was observed for the first time.     

Honeybee (Apis cerana) major royal jelly protein 4 exhibits antimicrobial activity

Major royal jelly proteins (MRJPs) are important protein components of bee royal jelly (RJ) and exhibit various biological and pharmacological activities. The antimicrobial activities of the royalisin and the jelleines contained within MRJP 1 and MRJP 2 in RJ have been elucidated. However, the antimicrobial effects of other MRJPs remain largely unknown. In this study, we demonstrated the antimicrobial activity of the Asiatic honeybee (Apis cerana) MRJP 4 (AcMRJP4). Recombinant AcMRJP4 was expressed as a 63-kDa protein in baculovirus-infected insect cells. We examined the antimicrobial activity of recombinant AcMRJP4 against bacteria, fungi, and yeast. The mechanisms underlying the antimicrobial activity of AcMRJP4 were assessed using western blot analysis, immunofluorescence staining, and scanning electron microscopy. Recombinant AcMRJP4 bound to the cell walls of bacteria, fungi, and yeast and induced structural damage in the microbial cell walls. AcMRJP4 has an antimicrobial role and exhibits a broad spectrum of antimicrobial activities against bacteria, fungi, and yeast. We demonstrated that AcMRJP4 functions as an antimicrobial agent with activity against bacteria, fungi, and yeast. Together, our data identified a novel function of MRJP 4 as an antimicrobial agent.     

Factors affecting antimicrobial activity of Synechococcus leopoliensis

An antimicrobial agent is produced by the cyanobacterium Synechococcus leopoliensis which was found to be active against the Gram-positive bacterium Staphylococcus aureus. The effects of temperature, pH, incubation period, some media and different nitrogen and carbon sources on both growth and antimicrobial activity were investigated. Temperature 35 °C and pH 8 were the best for growth and antimicrobial agent production and 14 and 15 days of incubation were found to be the best for maximum growth and antimicrobial activity, respectively, in the medium BG-11.

No antimicrobial activity could be detected by the use of G medium, moderate activity was recorded with Chu 10 medium, while high activity was reported in BG-11 medium. Leucine was the best nitrogen source for antimicrobial activity, while maximum antimicrobial activity was introduced by using the carbon sources, citrate and acetate. Very high antimicrobial activity could be detected by using the carbon source galactose in combination with the nitrogen source alanine or by using arabinose with methionine.     

抗菌肽结构改造与人工智能研发策略

抗菌肽是一类广泛存在于生物体内的小分子肽,参与构成生物体先天免疫,可以有效抵抗病原微生物的入侵。抗菌肽具有广谱抗菌活性,且不易产生耐药性等特点,在治疗感染性疾病方面具有独特的优势,有望成为理想的抗感染药物。然而,由于部分抗菌肽尚存在稳定性差、毒性高等问题,限制了抗菌肽的广泛应用。由于人工智能算法能有效合成具有高稳定性、低毒性的抗菌肽,在探索天然抗菌肽中展现了巨大的潜力,因此本文简述了抗菌肽的抗菌机制、结构改造以及利用机器学习和深度学习等人工智能算法进行新型抗菌肽研发的优化策略,以期为抗菌肽结构优化及研发提供新思路。     

全基因组测序与生物信息学分析在细菌耐药性研究中的应用

随着耐药细菌的大量出现及广泛传播,细菌耐药性成为全球备受关注的问题。耐药细菌的特征如耐药基因、毒力因子、质粒分型等以及不同菌株间亲缘关系对于细菌耐药性流行病学及分子生物学的研究有着十分重要的意义。但是传统的技术手段如聚合酶链式反应(Polymerase chain reaction,PCR)和脉冲场凝胶电泳(Pulsed field gel electrophoresis,PFGE)等得到的结果不够全面且精确度低,对于现有的研究存在很大的局限性。全基因组测序技术(Whole genome sequencing,WGS)和生物信息学分析(Bioinformatics analysis)由于能够快速详尽地得到耐药细菌的特征,也能更加精细地判断不同菌株间的进化关系,逐渐成为更加有效的技术手段,为耐药性研究提供了有效的帮助。因此,文中系统地介绍全基因组测序分析流程中的各个步骤,主要包括文库构建、平台测序以及后期数据分析三大方面的不同方法和其相应的特点,期望相关研究人员对此能够有更全面的了解,并得到一定的帮助。     

鲑鱼鱼精蛋白对食品防腐特性的研究

测定了鲑鱼鱼精蛋白食品常见污染菌的抗菌范围和抗菌力,探讨ＰＨ值、温度、食品中的我机成分、有机成分对鱼精蛋白菌活性的影响,阐明了鱼精帽白的抗菌特点和作为食品天然防腐剂的开发价值。     

辽宁某高校医学生抗菌药物认知水平调查

目的了解医学生对抗菌药物的认知水平及自主应用抗菌药物状况。方法采用分层整群抽样方法抽取调查对象,进行抗菌药物认知和使用的问卷调查。结果医学生抗菌药物认知较以前有提高,但仍存在误区。结论对抗菌药物应用认知水平的缺乏和不适当应用抗菌药物的现象在低年级医学生中依然存在,加强对抗菌药物应用知识的普及和宣传教育仍是当前之必需。     

九香虫抗菌肽CcAMP1的分离纯化和抗菌活性检测

【目的】从药用昆虫九香虫 Coridius chinensis 中分离纯化抗菌肽,为进一步开发九香虫抗菌肽资源及深入挖掘九香虫的药用功能奠定基础。【方法】用大肠杆菌Escherichia coli 和金黄色葡萄球菌 Staphylococcus aureus 混合物作诱导源刺激九香虫产生抗菌肽,对血淋巴进行提取、凝胶过滤层析、固相萃取及反相色谱纯化,活性组分经质谱测定。对分离得到的这种抗菌肽进行人工合成,并进行抗菌活性检测。【结果】本研究获得一种九香虫抗菌肽CcAMP1,由17个氨基酸残基组成,分子量为1 997.37 u,带1个正电荷,表面有5个疏水氨基酸。对人工合成的CcAMP1进行抗菌活性检测表明,该抗菌肽与九香虫血淋巴一样对金黄色葡萄球菌等革兰氏阳性菌和大肠杆菌等革兰氏阴性菌都有较好的抗菌活性,且对革兰氏阴性菌的抗菌活性更强。【结论】从九香虫中分离得到具有较强抗菌活性的阳离子抗菌肽CcAMP1,有较大的开发利用价值。     

Five novel antimicrobial peptides from the Kuhl’s wart frog skin secretions, Limnonectes kuhlii

Five novel antimicrobial peptides (temporin-LK1, rugosin-LK1, rugosin-LK2, gaegurin-LK1, and gaegurin-LK2) are purified and characterized from Kuhl’s wart frog skin secretions, Limnonectes kuhlii. They share obvious similarity to temporin, rugosin, and gaegurin antimicrobial peptide family, respectively. Their amino acid sequences were determined by Edman degradation and mass spectrometry, and further confirmed by cDNA cloning. Nine cDNA sequences encoding precursors of these five purified antimicrobial peptides and other four hypothetical antimicrobial peptides were cloned from the skin cDNA library of L. kuhlii. The deduced precursors are composed of a predicted signal peptide, an acidic spacer peptide, and a mature antimicrobial peptide. Most of them showed strong antimicrobial activities against Gram-positive and Gram-negative bacteria and fungi. The current work identified and characterized three families of antimicrobial peptides from L. kuhlii skins and confirmed that the genus of Limnonectes amphibians share similar antimicrobial peptide families with the genus of Rana amphibians. In addition, a unique antimicrobial peptide (temporin-LK1) with 17 residues including four phenylalanines, which is significantly different from other temporins (16 residues, one or two phenylalanines), was identified in this work. Such unique structure might provide novel template or leading structure to design antimicrobial agents.     

The in vitro Antimicrobial Activity and Chemometric Modelling of 59 Commercial Essential Oils against Pathogens of Dermatological Relevance

This study reports on the inhibitory concentration of 59 commercial essential oils recommended for dermatological conditions, and identifies putative compounds responsible for antimicrobial activity. Essential oils were investigated for antimicrobial activity using minimum inhibitory concentration assays. Ten essential oils were identified as having superior antimicrobial activity. The essential oil compositions were determined using gas chromatography coupled to mass spectrometry and the data analysed with the antimicrobial activity using multivariate tools. Orthogonal projections to latent structures models were created for seven of the pathogens. Eugenol was identified as the main biomarker responsible for antimicrobial activity in the majority of the essential oils. The essential oils mostly displayed noteworthy antimicrobial activity, with five oils displaying broad‐spectrum activity against the 13 tested micro‐organisms. The antimicrobial efficacies of the essential oils highlight their potential in treating dermatological infections and through chemometric modelling, bioactive volatiles have been identified.     

蜘蛛抗菌肽研究进展

蜘蛛活性多肽研究主要集中于蜘蛛毒液中作用于离子通道的神经毒素多肽。但近年来,一些蜘蛛抗菌肽不断被分离纯化,其结构和抗菌活性也被广泛深入研究,这将成为蜘蛛活性多肽研究领域的一个新热点。在蜘蛛毒液和血液中,存在不同种类的抗菌肽,其多肽长度、结构、抗菌作用各不相同。而且,有些抗菌肽甚至具有抗肿瘤作用。概述了蜘蛛抗菌肽在结构和功能方面的研究进展。