家蝇幼虫抗菌肽的抗菌谱及其与抗生素的协同作用研究

研究3种家蝇幼虫抗菌肽的抗菌谱以及每种抗菌肽的最小抑菌浓度(MIC),初步探讨3种抗菌肽分别与青霉素、链霉素相结合后对抗菌活性的影响,并采用分级抑制浓度指数(Fractionalinhibitoryconcentrationindex,FIC)来定量检测抗菌肽与抗生素之间的抗菌作用关系。结果表明3种抗菌肽的抗菌谱不同,不同的抗菌肽对不同病原菌的抗菌活性不同。3种抗菌肽与链霉素、青霉素之间的抗菌协同关系因细菌种类不同。抗菌肽与抗生素之间并不是都存在协同关系,有些不相关,甚至表现为对抗关系,表明抗菌肽、抗生素与细菌三者的相互作用关系非常复杂。     

牛乳酪蛋白源抗菌肽的研究进展

抗菌肽是具有抗菌活性的肽类物质的总称。除了广泛存在于生物体内的内源性抗菌肽外,已从酪蛋白的酶解产物中获得了多种外源性抗菌肽。抗菌肽的抗菌机理独特,有望成为新一代抗菌剂。简要综述了牛乳酪蛋白源抗菌肽的种类、抗菌机理及其研究展望。     

家蝇抗菌肽的抑菌动力学研究及其机理初探

利用鼠伤寒沙门氏菌针刺诱导家蝇幼虫表达抗菌肽,对抗菌肽的抑菌动力学进行研究,并通过抗菌肽样品对不同细菌动力学特性的研究出发对抗菌肽抑菌作用机制进行探讨。研究发现抗菌肽样品的活性与作用时间有关,24h内出现一到两个活性峰,同一抗菌肽样品对不同细菌的抑菌动力学有差异,抗菌肽的抑菌动力学机制应该与它的的抑菌作用机制有关。通过电镜观测、细胞磷代谢、紫外吸收物测定以及抗菌肽与细菌DNA相互作用结果可知,微生物诱导家蝇表达的抗菌肽样品不仅能够造成细菌细胞的快速坍塌破裂而且能够破坏细胞核心,与DNA结合作用。抗菌肽抑菌动力学的解释：微生物诱导产物中含有两类抗菌肽,一类抗菌肽能造成细胞膜的快速坍塌破裂形成第一个活性峰;另一类抗菌肽可进入细胞,破坏细胞核心,造成紫外吸收物大量外泄形成第二个活性峰。     

抗菌肽的研究进展

抗菌肽是一大类具有新型抗菌机理的抗生素,本文综述了抗菌肽的分类情况,抗菌肽的作用机制,以及部分正在开发的抗菌肽品种。     

Preparation and characterization of durable antibacterial cellulose biomaterials modified with triazine derivatives

Cellulose fabric was chemically modified with the triazine derivatives containing the multi-cationic benzyl groups. The novel durable antibacterial cellulose biomaterial containing the multi-cationic benzyl groups was prepared. The chemical structure and thermal property of the antibacterial cellulose biomaterial were investigated with FT-IR spectra, nitrogen content analysis, and differential scanning calorimetry (DSC). The results show that the thermal stability of the novel antibacterial cellulose was slightly decreased. Physical properties of the novel antibacterial cellulose had not significant change. The novel antibacterial cellulose imparted excellent durable antibacterial properties.     

Antibacterial components of honey

The antibacterial activity of honey has been known since the 19th century. Recently, the potent activity of honey against antibiotic-resistant bacteria has further increased the interest for application of honey, but incomplete knowledge of the antibacterial activity is a major obstacle for clinical applicability. The high sugar concentration, hydrogen peroxide, and the low pH are well-known antibacterial factors in honey and more recently, methylglyoxal and the antimicrobial peptide bee defensin-1 were identified as important antibacterial compounds in honey. The antibacterial activity of honey is highly complex due to the involvement of multiple compounds and due to the large variation in the concentrations of these compounds among honeys. The current review will elaborate on the antibacterial compounds in honey. We discuss the activity of the individual compounds, their contribution to the complex antibacterial activity of honey, a novel approach to identify additional honey antibacterial compounds, and the implications of the novel developments for standardization of honey for medical applications.     

抗菌肽及抗菌肽转基因植物研究进展

抗菌肽是一类小分子多肽,在生物体内分布广泛,具有广谱的抗菌性,是生物体内天然防御系统的一部分。主要介绍了抗菌肽的性质,类型,作用机制及抗菌肽转基因植物的研究进展。     

Antibacterial fatty acids: An update of possible mechanisms of action and implications in the development of the next-generation of antibacterial agents

The antibacterial activity of fatty acids (FA) is well known in the literature and represents a promising option for developing the next-generation of antibacterial agents to treat a broad spectrum of bacterial infections. FA are highly involved in living organisms' defense system against numerous pathogens, including multidrug-resistant bacteria. When combined with other antibacterial agents, the remarkable ability of FA to enhance their bactericidal properties is a critical feature that is not commonly observed in other naturally-occurring compounds. More reviews focusing on FA antibacterial activity, traditional and non-traditional mechanisms and biomedical applications are needed. This review is intended to update the reader on the antibacterial properties of recent FA and how their chemical structures influence their antibacterial activity. This review also aims to better understand both traditional and non-traditional mechanisms involved in these recently explored FA antibacterial activities.     

纳米银胶/壳聚糖复合抗菌剂的制备及其在洗涤产品中抗菌性能

本文研究了纳米银胶/壳聚糖抗菌剂的制备及其形貌的表征分析,以大肠杆菌为代表菌株,研究了复合抗菌剂在洗涤产品中的抗菌效率及抗菌的稳定性,结果说明复合抗菌剂在洗涤产品中添加1.0%时,其抗菌效率达99%,经180 d长期分析,其抗菌活性仍保持95%左右。此外,复合抗菌剂对不同菌株的抗菌性能也均较强。     

壳聚糖对大肠杆菌的抑制作用规律及抗菌机理初探

考察了不同分子量壳聚糖对大肠杆菌的抑菌性能,利用壳聚糖的席夫碱反应对其氨基加以保护,探讨了壳聚糖对大肠杆菌的抗菌机理。研究结果表明:壳聚糖分子量越小,对大肠杆菌的抗菌作用越明显;壳聚糖对大肠杆菌的抑菌作用与其氨基的质子化有关。     

铜绿假单胞菌抗菌物质对耐甲氧西林金黄色葡萄球菌的抑菌活性研究

目的观察铜绿假单胞菌抗菌物质对耐甲氧西林金黄色葡萄球菌(methicillin-resistant Staphylococcusaureus,MRSA)的体外抑菌活性。方法用交叉划线接种方法进行铜绿假单胞菌对32株耐甲氧西林金葡菌的体外抗菌活性的测定。结果铜绿假单胞菌抗菌物质对MRSA的体外抑菌活性良好,产生色素的菌株的抗菌活性最好,15株铜绿假单胞菌中,7株产蓝绿色色素的铜绿假单胞菌,对MRSA的抑制率均达到了100%,平均抑菌带的宽度为37.7 mm。结论铜绿假单胞菌抗菌物质对32株MRSA具有较强的抗菌活性,无疑对MRSA感染的抗菌药物研制方面开辟了一条新的途径。这是国内的首次研究报道。     

光生物调节作用的在体杀菌策略

世界范围的细菌耐药性呼吁新的抗菌策略,光生物调节作用是有效的候选手段之一。论述了光生物调节作用抗菌效应的研究现状和应用前景。中性粒细胞可以通过吞噬杀菌,也可以通过产生胞外菌阱杀菌。还从活性氧和信号转导所介导的中性粒细胞杀菌作用讨论了光生物调节作用的抗菌机理,为其在临床抗菌中的应用提供理论依据。     

四种野生蕨类植物抑菌作用分析

研究了四种野生蕨类植物水提液和醇提液对五种常见微生物的抑菌情况,研究结果显示具有较好的抑菌效果。大多数情况下,其醇提液抑菌作用优于其水提液的,其中狗脊蕨表现了普遍较高的抑菌活性。     

抗菌肽研究进展

抗菌肽是广泛存在于自然界生物中的一种具有抗菌、抗病毒和抗肿瘤活性的多态,由于抗菌肽具有普通抗生素所不具有的一系列优点,抗菌肽的研究已经成了现代学术和应用研究的一个热点。作者综述了抗菌肽的抗菌机制和应用研究等方面的内容。     

普外科切口感染病原菌及细菌耐药性分析

目的探讨普外科切口感染菌分布及耐药性,指导临床用药及预防控制措施。方法总结分析本院2003年1月至2005年5月普外科124例切口感染住院患者的病原菌资料。结果124例切口感染标本中共分离出感染菌127株,病原菌依次为:大肠埃希菌占47.24%、肠球菌占18.90%、金黄色葡萄球菌占12.60%、肠杆菌属占7.87%、真菌占7.09%、克雷伯菌属占6.30%。以革兰阴性菌为主占61.41%,革兰阳性菌占31.50%,真菌占7.09%。大肠埃希菌与克雷伯菌的耐药性相仿,对哌拉西林/他唑巴坦、头孢西丁、头孢吡肟、亚胺硫霉素、阿米卡星的耐药率较低,肠杆菌属仅对亚胺硫霉素和阿米卡星的耐药率低,肠球菌仅对万古霉素的耐药率低,金黄色葡萄球菌MRSA检出率为25%,除对青霉素和氨苄青霉素的耐药率较高外,对其它抗菌药物的耐药率尚处于低水平。结论细菌耐药性是引起术后感染、治愈困难的重要原因之一,加强细菌耐药性监测,采用合理预防控制措施,能减低术后切口感染的发生。     

肠球菌E4及其抑菌产物特性的研究

目的获得抑制微生物生长的菌株。方法根据形态学和生理生化学特性进行菌种鉴定;采用牛津杯法测定抑菌谱和抑菌物质的理化特性。结果排除了过氧化氢和有机酸的作用,该菌发酵上清液对苏云金杆菌、枯草杆菌、大肠埃希菌、鸡白痢沙门菌等有抑制作用。根据菌株的生理生化特征,该菌株初步定为肠球菌属,定名为E4（Enterococcus sp．）。所产抑菌物质具有较好的热稳定性,在酸性条件下稳定且活性高。结论分离筛选了1株可产抑菌物质的肠球菌,其产生的抑菌物质具有良好的生物化学特性和广谱的抑菌能力。     

纳米银/植物源复合抗菌剂的制备及其抑菌性能的研究

以硝酸银作为银源,水溶性淀粉作保护剂,丙酮酸钠作还原剂,氨水提供碱性环境来制备纳米银胶,并以聚乙烯吡咯烷酮(PVP)作分散稳定剂,复配红景天提取液和无患子提取液制备出纳米银/植物源复合抗菌剂。实验结果表明,纳米银胶或植物提取液仅对部分细菌或霉菌有较强抑制效果,而复合抗菌剂对细菌、霉菌均有很强抑制效果。在湿巾液中添加0.5%复合抗菌剂时,其对大肠杆菌,金黄色葡萄球菌和白色念珠菌的抗菌效率可达99%,且经过常温六个月、高温55℃一个月保存后,其抗菌活性分别可达到95%、90%左右,表明复合抗菌剂具有较强的抗菌效率及抗菌稳定性。     

昆虫抗菌肽分类及在医学中应用

昆虫是地球上种类最为繁多的生物,其抗菌肽的种类和应用范围也远多于其他生物产生的抗菌肽。随着越来越多昆虫抗菌肽的发现及对其深入的研究,昆虫抗菌肽的结构和作用机制也被逐一阐明,并广泛应用于畜牧、食品工业及医药等领域。然而,由于某些限制因素,昆虫抗菌肽还未应用于临床。为了加快昆虫抗菌肽在临床中的应用,本文将从昆虫抗菌肽的结构分类、潜在的医学应用以及昆虫抗菌肽的生产研究现状等方面作一综述,以期为昆虫抗菌肽在抗细菌、抗病毒、抗肿瘤及抗寄生虫药物等方面的医用研发提供文献支持。     

Synthesis and antibacterial activity evaluation of metronidazole–triazole conjugates

Synthesis and antibacterial activity of metronidazole–triazole conjugates are reported. Total 21 hybrid compounds have been synthesized with different substitution pattern on the triazole ring in order to study their influence on the antibacterial activity. These compounds demonstrated potent to weak antibacterial activity against Gram-positive, and Gram-negative bacteria. Six compounds have shown equal or better antibacterial activity against Gram-negative strains than the reference compound.     

Effect of abiotic factors on the antibacterial activity of chitosan against waterborne pathogens

To assess the adaptability of chitosan (from agricultural waste) as a natural disinfectant, its antibacterial activity against bacteria associated with waterborne diseases was investigated by varying such abiotic conditions, as pH and ionic strength and by adding different amounts of acid solvent, metal ions, and EDTA. Two major waterborne pathogens, Escherichia coli and Staphylococcus aureus, were examined. Results showed that organic acids with low carbon number were better solvents for chitosan than were inorganic acids. The effect of pH below 6 on the antibacterial activity of chitosan was significant. The antibacterial activity of chitosan increased with ionic strength but decreased with the addition of metal ions. The addition of Zn(2+) ions inhibited the antibacterial activity of chitosan the most, while the addition of Mg(2+) ions inhibited the antibacterial activity of chitosan the least. This was due to the chelating capacity of chitosan toward metal ions. The antibacterial activity of chitosan against E. coli was enhanced by EDTA. However, the antibacterial activity of chitosan against S. aureus was partially suppressed by EDTA. The antibacterial activity of chitosan was also dependent on its charges and solubility. The antibacterial mechanism of chitosan has currently been hypothesized as being related to surface interference. The results show that the chitosan is a potential bactericide under various environmental conditions.