食源性致病微生物危害风险及其防控用抗菌生物活性肽研究进展

食源致病微生物是污染食品、食用农产品的主要生物危害物,严重威胁人类及动物健康;同时也给食品、食用农产品产业造成巨大经济损失,是制约产业健康可持续发展的关键危害因素。传统依赖抗生素对致病微生物的防控效果显著,但由于抗生素长期的不合理使用甚至是滥用所诱发产生的致病微生物耐药性,以及对人类和动物体内脏器、肠道组织、神经和代谢系统正常功能构成的潜在危害性等问题也同样突出。抗菌生物活性肽作为具有抗菌功能的生物多肽类蛋白质,被认为是对人类、动物以及生态环境友好的抗菌物质,有望替代抗生素用于致病微生物的防控,现已成为探索新型安全抗菌类药物研发的热点。全面梳理了食源致病微生物种类、污染特点及其主要危害风险;系统概述了抗菌生物活性肽主要类型、来源及其创制技术;着重介绍了当前抗菌生物活性肽在食源致病微生物防控上的研究状况,并深入探讨了其应用前景、存在问题及拟解决对策,旨在为食品、食用农产品中食源性致病微生物筛查以及靶向防控技术提供最新的有参考价值的文献资料和创新思路。

10种天然产物抗茶轮斑病的生物活性

【目的】筛选抗茶轮斑病的活性天然产物,为降低茶叶农药残留和提高贵州茶叶品质提供技术支撑。【方法】采用菌丝生长速率法,测试10种天然产物(香草醛、丁香醛、愈创木酚、百里香酚、吲哚、槲皮素、香叶木素、芹菜素、肉桂酸和L-薄荷)在100μg/mL浓度下抗茶轮斑病的生物活性,并进行EC_(50)测定;通过扫描电子显微镜(SEM)观察初筛生物活性最好的天然产物在不同浓度下对茶轮斑病细胞外壁的损伤程度。【结果】在10种天然产物中,以百里香酚、愈创木酚和吲哚的生物活性较好,其对茶轮斑病的抑制率分别为82.67%、65.33%和57.33%,比阳性对照萎锈灵(34.67%)分别增加48百分点、30.66百分点和22.66百分点,差异均达极显著,其EC_(50)分别为33.79μg/mL、56.97μg/mL和75.42μg/mL,比阳性对照萎锈灵(231.52μg/mL)的EC_(50)剂量分别减少197.73μg/mL、174.55μg/mL和156.10μg/mL。在200μg/mL浓度时,百里香酚可导致茶轮斑病真菌细胞壁的表面形态从光滑圆润变为部分裂开;在500μg/mL浓度时,真菌细胞壁的受损程度明显增加。【结论】百里香酚抗茶轮斑病的生物活性最好,愈创木酚和吲哚较好。

柳珊瑚共附生放线菌Streptomyces sp.SCSGAA0009中生物碱类化合物及其抗菌和抗附着活性

【目的】从南海柳珊瑚共附生放线菌的次生代谢产物中寻找具有抗菌和抗附着活性的先导化合物。【方法】应用化学与生物活性相结合的筛选方法,从柳珊瑚共附生微生物中筛选获得代谢产物丰富且具有生物活性的目标菌株并通过大发酵提取浸膏,利用硅胶柱色谱、凝胶柱色谱和高效液相色谱等方法对发酵产物进行分离、纯化,运用波谱解析鉴定化合物的结构。【结果】从采自海南三亚的柳珊瑚(Muricella flexuosa)样品中分离到一株放线菌SCSGAA0009,鉴定为链霉属Streptomycessp.,从其改良ISP2发酵液中分离到新化合物N-(2-(1H-indol-3-yl)ethyl)propionamide(1)和已知化合物phenazine-1-carboxylic acid(2),其中化合物2对大肠杆菌和海洋细菌假单胞菌(Pseudoaltermonas piscida)具有较好抗菌活性,且有强抗草苔虫(Bugulaneritina)幼虫附着活性。【结论】首次从柳珊瑚共附生放线菌的次生代谢产物中获得新的生物碱化合物1,首次报道化合物2的抗海洋细菌活性和抗附着活性;从南海柳珊瑚共附生微生物的次生代谢产物中可以得到新化合物和活性化合物,这一来源的微生物资源值得深入研究。

9种天然产物对茶炭疽病的抑制效果

【目的】探明植物源天然绿色农药抑制茶炭疽病的效果,为茶树炭疽病的绿色防控和绿色农药的研制提供参考。【方法】采用菌丝生长速率法,测试9种天然产物在100μg/mL浓度下抗茶炭疽病的生物活性,并进行EC_(50)测定;通过抗茶炭疽病活体试验,测定生物活性最好的天然产物在500μg/mL浓度下对茶叶感染茶炭疽病的保护和治疗效果。【结果】在9种天然产物中,以百里香酚和愈创木酚抗茶炭疽病的生物活性较好,其对炭疽病菌的抑制率分别为83.33%和76.55%,比阳性对照萎锈灵(74.69%)分别增加8.64百分点和1.86百分点;其EC_(50)分别为18.55μg/mL和25.11μg/mL,比阳性对照药萎锈灵(35.53μg/mL)分别减少用药剂量16.98μg/mL和10.42μg/mL。在500μg/mL浓度下,百里香酚对茶叶感染茶炭疽病的保护活性和治疗活性分别为32.66%和38.09%,比阳性对照萎锈灵(20.42%和25.72%)分别增加12.24百分点和12.37百分点。【结论】百里香酚对茶叶感染茶炭疽病具有较好的保护和治疗效果。

Comparative Study of the Biological Activities of the Skin Secretions from Six Common Chinese Amphibians

Water soluble skin secretions of six common Chinese amphibians were studied for their biological and enzymatic activities.The skin secretions of Tylototriton verrucosus,Bombina maxima ,and Bufo andrewsi were found toxic to mice with the intraperitoneal LD 50 of 11 5?mg/kg,18 8?mg/kg,and 264?mg/kg,respectively.No acute lethal toxicities were observed for the skin secretions of Rana nigromaculata,Rana guentheri and Rana limnocharis in a dose up to 500?mg/kg.The lethal toxicities of the skin secretions of T verrucosus and B maxima to mice are in the same grade as those of Viperidae snake venoms.The toxic components in T verrucosus and B maxima skin secretions are the proteins with molecular weights ranging from 3 to 60?kDa.All the skin secretions had both proteolytic activity and trypsin inhibitory activity.The skin secretions from T verrucosus , B maxima and B andrewsi also displayed wide spectrum antimicrobial activity.On the other hand,the skin secretions from B andrewsi and B maxima showed cytotoxicity on human cancer cells.All the six samples had not significant effects on mammalian blood coagulation system.Phospholipase A 2 activity was only found in the skin secretions of T verrucosus .None of these skin secretions showed acetylcholine esterase activity.

A Bioactive Diterpene from the Chinese Herb Aster souliei

Aster souliei Franch, (Compositae) is a. herbaceous plant distributed innorth China. It has been used in folk medicine as antipyretic, detoxicant, expectorant andantitussive. In an effort to find biologically active components from Chinese medicinal plants ' ,we have examined the aerial parts of this herb, leading to the isolation of a clerodane-typediterpene, 18, 19-dihydroxy-5α, 10β-neo-cleroda-3, 13 (l4)-dien-16, 15-butenolide (1). In thispaper we report the structural elucidation, and the antitumor and antibacterial activities of thiscompound. It was found that 1 possesses moderate cytotoxicity against human leukemia cells (HL-60)and activity against microorganisms.

Synthesis and Antibacterial Activities of Erythromycin Derivatives

Aim To synthesize 4″-carbamate derivatives of erythromycin and test their antibacterial activities in vitro. Methods New erythromycin antibacterial agents containing 4″-carbamate group were designed and synthesized from azithromycin via protection, aminoformylation, amination and deprotection. Their antibacterial activities against Staphylococcus aureus strains were tested. Results Nine compounds were synthesized. Their structures were confirmed by MS, IR, ~ 1 H NMR and ~ 13 C NMR, and the synthetic conditi...

Determination of the Content of Total Alkaloids in Different Solvent Extracts from Climbing Groundsel Herb Produced in Guizhou Province and Their Antibacterial Activity

[Objective] This study aimed to compare the contents of total alkaloids in different solvent extracts from climbing groundsel herb produced in Guizhou Province and their antibacterial activity. [Method] The content of total alkaloids was measured by UV spectrophotometry, and Oxford cups were used to investigate the antibacterial activity of each solvent extract. [Result] There was a good linear correlation between the absorbance measured by the UV spectrophotometer and the content of total al- kaloids within the concentration of 0.011 0-0.054 8 mg/ml at 207 nm, and the re- gression equation was Y=23.654X＋0.021, R=0. 999 7 and the average recovery rate was 99.2%. The contents of total alkaloids in 60% ethanol extract, 95% ethanol and water ethanol were 38.71, 52.25 and 60.50 mg/g, respectively. The 60% ethanol ex- tract had strong antibacterial activity against Streptococcus pneumoniae, Staphylo- coccus aureus and Escherichia coil; the water extractive had stronger antibacterial activity against Escherichia colr, 95% ethanol extract had weak antibacterial activity, with no inhibition of Pseudomonas aeruginosa. [Conclusion] This method is accurate, simple, with good repeatability, which can be used for the determination of alkaloids content of the climbing groundsel herb; there is no positive correlation between the content of total alkaloids in different solvent extracts of climbing groundsel herb and their antibacterial activity.

Preliminary Test on a New Type of Antibacterial Substance

Application of high-speed centrifugation and high-performance liquid chro- matography to separation and purification obtained a new type of natural antibacteri- al substance from Escherichia co/i cell. Against Staphy/ococcus aureus, Escherichia coli, Pasteurella multocida, Streptococcus, Pseudomonas, solanacearum the minimal inhibitory concentration （MIC） was 2.5, 5, 0.625 iJg/ml, 0.625 and 1.25 g/ml, the minimum bactericidal concentration （MBC） was 5, 5, 1.25, 2.5, 2.5 g/ml, respectively. Composition identification of chemical method and mass spectrometry shows that the antibacterial active substance alkaloids; and the safety evaluation on the model plant Arabidopsis shows that the antibacterial active substance had no inhibitory and adverse effects on the growth and development of plants. The experimental results show that the antibacterial active substance is a broad-spectrum, high efficiency, safe antibacterial natural product, with the prospect of development and utilization of alternative antibiotics.

Synthesis and in-vitro characterization of biodegradable porous magnesium-based scaffolds containing silver for bone tissue engineering

Infection is a major potential complication in the clinical treatment of bone injuries. Magnesium (Mg)-based composites are biodegradable and antibacterial biomaterials that have been employed to reduce infection following surgical implants. The aim of present study was to synthesize and in-vitro characterize Mg-based scaffolds containing silver for bone tissue engineering. Porous Mg-based scaffolds with four silver concentrations (i.e., 0, 0.5 wt.%, 1 wt.%, and 2 wt.%), denoted by Mg?Ca?Mn-Zn-xAg (MCMZ?xAg)(where x is the silver concentration), were fabricated by the space holder technique. The effects of silver concentration on pore architecture, mechanical properties, bioactivity, and zone of bacterial inhibition were investigated in-vitro. X-ray diffractometry (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and fluorescence microscopy were utilized to characterize the obtained scaffolds. In-vitro corrosion test results indicated that the MCMZ scaffolds with lower silver content were more resistant to corrosion than those enriched with higher amounts of silver. Examination of the antibacterial activity showed that the MCMZ?Ag scaffolds exhibited superb potential with respect to suppressing the growth of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), in the inhibition zone around the MCMZ?Ag scaffolds, with increasing in the amount of incorporated silver;however, higher amounts of silver increased the cytotoxicity. Taken together, the results of this study demonstrate that the porous 0.5 wt.% Ag-containing scaffolds with interconnected pores, adequate mechanical properties, antibacterial activity, and cell adhesion are promising with respect to the repair and substitution of damaged and diseased bones.

Microstructure,anticorrosion,biocompatibility and antibacterial activities of extruded Mg−Zn−Mn strengthened with Ca

To find suitable biodegradable materials for implant applications,Mg−6Zn−0.3Mn−xCa(x=0,0.2 and 0.5,wt.%)alloys were prepared by semi-continuous casting followed by hot-extrusion technique.The microstructure and mechanical properties of Mg−6Zn−0.3Mn−xCa alloys were investigated using the optical microscope,scanning electron microscope and tensile testing.Results indicated that minor Ca addition can slightly refine grains of the extruded Mg−6Zn−0.3Mn alloy and improve its strength.When 0.2 wt.%and 0.5 wt.%Ca were added,the grain sizes of the as-extruded alloys were refined from 4.8 to 4.6 and 4.2μm,respectively.Of the three alloys studied,the alloy with 0.5 wt.%Ca exhibits better combined mechanical properties with the ultimate tensile strength and elongation of 334 MPa and 20.3%.The corrosion behaviour,cell viability and antibacterial activities of alloys studied were also evaluated.Increasing Ca content deteriorates the corrosion resistance of alloys due to the increase of amount of effective cathodic sites caused by the formation of more Ca2Mg6Zn3 phases.Cytotoxicity evaluation with L929 cells shows higher cell viability of the Mg−6Zn−0.3Mn−0.5Ca alloy compared to Mg−6Zn−0.3Mn and Mg−6Zn−0.3Mn−0.2Ca alloys.The antibacterial activity against Staphylococcus aureus is enhanced with increasing the Ca content due to its physicochemical and biological performance in bone repairing process.

Bioactivity,in-vitro corrosion behavior,and antibacterial activity of silver-zeolites doped hydroxyapatite coating on magnesium alloy

Mg-based alloys received significant attention for temporary implant applications while, their applications have been limited by high degradation rate. Therefore, silver-zeolite doped hydroxyapatite（Ag-Zeo-HAp） coating was synthesized on Ti O2-coated Mg alloy by physical vapour deposition（PVD） assisted electrodeposition technique to decrease the degradation rate of Mg alloy. X-ray diffraction（XRD） analysis and field emission scanning electron microscopy（FE-SEM） images showed the formation of a uniform and compact layer of Ag-Zeo-HAp with a thickness of 15 μm on the Ti O2 film with a thickness of 1 μm. The potentiodynamic polarization（PDP） and electrochemical impedance spectroscopy（EIS） tests indicated that corrosion resistance of Mg-Ca alloy was considerably increased by the Ag-Zeo-HAp coating. The bioactivity test in the simulated body fluid（SBF） solution showed that a dense and homogeneous bonelike apatite layer was formed on the Ag-Zeo-HAp surface after 14 d. Investigation of antibacterial activity via disk diffusion and spread plate methods showed that the Ag-Zeo-HAp coating had a significantly larger inhibition zone（3.86 mm） towards Escherichia coli（E. coli） compared with the Ti O2-coated Mg alloy（2.61 mm）. The Ag-Zeo-HAp coating showed high antibacterial performance, good bioactivity, and high corrosion resistance which make it a perfect coating material for biomedical applications.

Antibacterial activity of nanostructured Ti-45S5 bioglass-Ag composite against Streptococcus mutans and Staphylococcus aureus

Mechanical alloying and annealing at 1150 °C for 2 h under an argon atmosphere were used to prepare Ti-45S5 bioglass nanocomposites. Ti-45S5 bioglass material was chemically modified by silver. The antibacterial activity of Ti-10% 45S5 bioglass nanocomposite containing silver against Streptococcus mutans and Staphylococcus aureus was studied. Nanocomposites were characterized by X-ray diffraction, scanning electron microscopy equipped with an electron energy dispersive spectrometer and transmission electron microscopy to evaluate phase composition, crystal structure and grain size. In vitro bacterial adhesion study indicated a significantly reduced number of Streptococcus mutans and Staphylococcus aureus on the bulk nanostructured Ti-45S5 bioglass-Ag plate surface in comparison to that on microcrystalline Ti plate surface. Nanostructured Ti-based biomaterials can be considered to be the future generation of dental implants.

Some Antimicrobial Activity Plants Growing in Rize Region Used in Alternative Medicine

Rize has a different and special flora because of its geographical position, climate, and topography. The natural plants of Rize have a very big usage potential and value in some sort of intrustrial branches. In particular, the antimicrobial activity of natural plant oils and extracts has formed the basis of many applications, including raw and processed food preservation, pharmaceuticals, alternative medicine and natural therapies： These natural plants can be listed as follows： Artemisia absinthium L., Achi[[ea millefolium L., Astragalus schizopterus Boiss, Ajuga orientalis L., Humulus lupulus L,, Mentha longifolia L., Melissa officinalis L., Thymus pseudopulegioides Klokov et Des., Plantago major L., Rhus L., Hypericum perforatum L., Camellia chinensis L., Taraxacum officinale Wobb., duniperus communis L., etc.. In the present study, the bio-eco-morphological features of some antimicrobial activity plants, their active substance content, their effectuality and usage as traditional medicine in Rize region were discussed. It was observed that these herbs are preferred by experts and they are sold in the neighborhood markets and spice stores, and the local people are quite interested in these medicinal herbs.

Natural products from Bacillus subtilis with antimicrobial properties

Bacillus subtilis produces many chemlcally-dwerse seconaary metaDolltes or interest to chemists ano biologlsts. Based on this, this review gives a detailed overview of the natural components produced by B. subtilis including cyclic lipopeptides, polypeptides, proteins （enzymes）, and non-peptide products. Their structures, bioactive ac- tivities and the relevant variants as novel lead structures for drug discovery are also described. The challenging effects of fermentation metabolites, isolation and purification, as well as the overproduction of bioactive com- pounds from B. subtilis by metabolic engineering, ＇~ere also highlighted. Systematically exploring biosynthetic routes and the functions of secondary metabolites from 13. subtilis may not only be beneficial in improving yields of the products, but also in helping them to be used in food industry and public medical service on a large-scale.

Preparation, characterization, and antifungal activity of hymexazol-linked chitosan derivatives

In this study, three hymexazol-linked chitosan derivatives （HML-CS） were synthesized and their structures confirmed by Fourier transform infrared and elemental analysis. Linkage ratios were measured by high performance liquid chromatography. The derivatives＇ antifungal activity against the plant pathogenic fimgi Rhizoctonia solani CGMCC 3.28 and Gibberella zeae CGMCC 3.42 were investigated at concentrations of 100, 200, and 400 mg/L. These HML-CS derivatives exhibited stronger antifungal activity than CS alone. HML-CS-1 showed the best antifizngal activity against G. zeae, whose antifimgal index was 65.9% at 400 mg/L, and also showed the best antifungal activity against R. solani, whose antifimgal index was 52.7% at 400 mg/L. This conjugation of CS and HML suggested the presence of synergistic effects between the moieties and indicated that these derivatives possessed great potential as novel fungicides and require further research for the development of applications in crop protection.

Synthesis and Antibacterial Activity of Juglone Derivatives

Nitro and halogen substituted derivatives of the juglone naphthoquinone were synthesized and assayed for their antibacterial activity. 8-Nitrojuglone was obtained as the exclusive product from the direct nitration of juglone with nickel （Ⅱ） nitrate and p-toluenesulphonic acid. In addition, a series of five 8-halojuglone derivatives were synthesized via a solvent-free Friedel-Crafts acylation reaction. One of the acylation reactions afforded an anthraquinone-type derivative as the minor product. The 8-nitrojuglone derivative displayed the most notable activity against S. aureus. However, all of the 8-halojuglone derivatives were found to be less active than juglone against the bacteria assayed.

In Vitro Antimicrobial Activity Study of Some New Arginine-based Biodegradable Poly （Ester Urethane）s and Poly （Ester Urea）s

Bactericidal activity of some arginine based biodegradable polymers-PEURs （poly （ester urethane）s） and PEUs （poly （ester urea）s） with low cytotoxicity was studied in in vitro experiments. Various bacterial strains both Gram-positive and Gram-negative were used to explore the bactericidal activity of the cationic polymers. As the test objects, the following microorganisms were used： Bacillus subtilis, Staphylococcus aureus, Mycobacterium album, Pseudomonas fluorescens, Escherichia coli, Actinomyces griseus and Aspergillus niger. The obtained results showed that the new cationic polymers suppressed the growth of the studied microorganisms and the bactericidal activity of the tested cationic polymers strongly depending on their chemical structure.

Antibacterial Activity of Extract and an Isolated Steroidal Alkaloid from the Seeds of Combretum quadrangulare Kurz

The purpose of this study was to isolate a new compound from the seeds of Combretum quadrangulare Kurz, which showed antibacterial activity. The seeds were macerated with 95% of ethanol and then purified by column chromatography using Avicel as the adsorbent. After that, 50% of methanol in water was used as the eluting solvent and continued to further purify by Avicel preparative layer chromatogram 2 times using 80% of methanol in water as developing solvent. MIC of pure compound was done by two fold dilution method. Muller Hinton agar was selected as the media. The new compound was found as combretin, a steroidal alkaloid, and showed antibacterial activity against Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853 better than Staphylococcus aureus ATCC 25923.

Anti-mycobacterium and Anti-cancer Activities of Combretin, an Isolated Steroidal Alkaloid from the Seeds of Combretum quadrangulare Kurz.

Combretin is the steroidal alkaloid isolated from the seeds of Combretum quadrangulare Kurz. by macerated powder of the seeds with 95% ethanol. Purified further by avicel column chromatography and preparative thin layer chromatography. Combretin was investigated for anti-mycobacterium and anti-cancer activities. Combretin was inactive against Mycobacterium tuberculosis but showed anti-cancer activities against human hepatocarcinoma （Hep G2） ATCC HB-8065 and human caucasian colon adenocarcinoma （Caco2） ATCC HTB-39 at concentration greater than 300 mcg/ml in DMSO （Dimethyl sulfoxide）.