精氨酸对引起采后蓝莓腐烂的链格孢靶标菌的抑制效果研究

目的 旨在筛选引起蓝莓采后腐烂的链格孢靶标菌株,并比较L-精氨酸和山梨酸钾对其抑制效果,为蓝莓采后链格孢腐烂病的防控提供前期基础。方法 通过组织分离法结合单孢分离法进行致腐菌的分离,采用ITS序列分析进行属水平鉴定,采用ATP序列分析结合形态学观察进行种水平鉴定,采用平板抑菌法比较L-精氨酸和山梨酸钾的抑菌效果。结果 本研究分离获得的链格孢菌均有致病性,分别属于3个不同种群,分别为细极链格孢(Alternaria tenuissima)、互隔交链孢(A. alternata)和云南铁杉链格孢(A. dumosa)。以菌株B20190623E3(A. tenuissima代表菌株)、菌株B20190623B1(A. alternata代表菌株)、菌株B20190623C1(A. dumosa代表菌株)为靶标菌,发现L-精氨酸对供试3株靶标菌的EC50值均低于山梨酸钾。结论 供试链格菌株均有致病性,其中引起蓝莓采后腐烂的优势链格孢种群为细极链格孢。云南铁杉链格孢为引起蓝莓果实腐烂的新纪录种。筛选获得了3株链格孢代表靶标菌。L-精氨酸对引起蓝莓采后腐烂的链格孢菌具有较好的抑制效果。     

1-MCP和丁香精油对苹果链格孢和曲霉抑性的影响

目的 研究1-MCP和丁香精油在离体和活体条件下对采后苹果的主要致腐菌（苹果链格孢和曲霉）的抑制作用。方法 以‘寒富’苹果为实验材料,通过分离纯化腐烂寒富苹果上的菌后,再进行体外抑菌实验和苹果活体接种试验。结果 从腐烂寒富苹果中分离得到链格孢和曲霉等2个属。致腐能力由大到小为曲霉、链格孢。在离体条件下,1-MCP和丁香精油对供试菌种有显著的抑制作用,1-MCP对苹果链格孢、曲霉的最低抑制含量分别为8 μL/L和9 μL/L。丁香精油对苹果链格孢、曲霉的最低抑制含量分别为5 μL/L和7 μL/L。在活体实验中,1-MCP（5 μL/L）处理对苹果果实病斑直径扩展的控制作用最显著,对链格孢的抑菌率在第6 d时达到18.17%,对曲霉的抑菌率在第6 d时达到27.31%。丁香精油的活体最佳抑菌含量为12 μL/L,在第6 d时对链格孢的抑菌率可达79.36%,对曲霉的抑菌率达到34.82%。结论 实验中1-MCP的最佳用药含量为5 μL/L,丁香精油为12 μL/L。1-MCP对果实上曲霉的抑制效果较显著,而丁香精油对链格孢的抑制作用更好。     

基于可培养技术的中国家用洗衣机中真菌多样性研究

本文通过可培养方法分析中国家用洗衣机中的真菌多样性，采用不同培养基对洗衣机不同位置的真菌进行分离，通过序列分析进行鉴定。结果表明从14台洗衣机的57个样品中共分离获得真菌253株，涵盖36个属。洗衣机中优势真菌主要有青霉属（Penicillium）、枝孢菌属（Cladosporium）、曲霉属（Aspergillus）、镰刀菌属（Fusarium）、紫霉属（Purpureocillium）等。研究结果为洗衣机中具有致味、致污、致病和抗逆功能的特征微生物的定向筛选、抗菌抑菌试验的开展以及作用机制的研究奠定了基础。     

申克氏孢子丝菌的形态学及低温生物学研究

观察了在沈阳地区分离培养的申克氏孢子丝菌的超微结构和繁殖方式,并对实验菌株进行了低温生物学研究。结果发现该菌株与既往文献中报道的美国、日本及北京的同种真菌具有不同的结构和繁殖方式,即该菌株具有膨大的、呈营养型发育的假单轴状分生孢子柄,能够连续产生分生孢子,故可鉴定为申克氏孢子丝菌,而易与无此种分生孢子柄的侧孢霉属相鉴别;实验菌株具有两种繁殖方式,即全壁芽殖型发育和全壁菌体型发育;冻融对实验菌株具有损伤作用,两次冻融时细胞损伤加重,冻融后再培养生长的该菌株的芽殖现象,随冻融条件的加深而减少,细胞活性降低,从而为冷冻疗法治疗孢子丝菌病提供了初步的理论依据,并可推测反复冻融法较一次冻融法疗效更佳。     

牙鲆与大菱鲆病原迟钝爱德华氏菌生物学特性及系统发育学分析

对从7起牙鲆（Bastard halibut,Paralichthys olivaeeus L．）、3起大菱鲆（Turbot,Scophdudmus maximus L．）病害的病（死）鱼中分离到的相应病原菌较系统地进行了形态特征、理化特性等表观分类学指征的鉴定及代表菌株DNA中G＋Cmol％的测定。同时,择代表菌株进行了16SrRNA基因的分子鉴定,测定了16SrRNA基因序列,分析了相关细菌相应序列的同源性,构建了系统发生树。结果表明,分离鉴定的148株菌均为爱德华氏菌属（Edwardsiella Ewing and McWhorter 1965）的迟钝爱德华氏菌（E．tarda）,其中128株为迟钝爱德华氏菌野生型（E．tarda wild type）菌株,20株暂定为迟钝爱德华氏菌吲哚阴性变异株。代表菌株（HC010907—1及HC010830-1）的16SrRNA基因序列,与GenBank数据库中的迟钝爱德华氏菌的同源性均在99％。     

掺Zn纳米TiO2对6种植物病原菌的抑菌性能研究

通过溶胶-凝胶法制备TiO_2纳米材料,并进行Zn~(2+)掺杂改性,采用冷冻干燥法获得纳米微粉,在自然光下对红枣链格孢、黄瓜枯萎病、辣椒疫霉病、棉花枯萎病、棉花黄萎病和玉米弯孢等6种病原菌做抗菌实验,研究其对植物病原微生物的杀灭与抑制作用。用X射线衍射仪和透射电镜进行物性表征,采用菌丝抑制率法统计病原菌存活数、相对抑菌率。结果表明:冷冻干燥处理的TiO_2材料颗粒大小均匀,抑菌能力好于焙烧处理,Zn~(2+)掺杂后纳米TiO_2对植物病原菌抑制与未掺杂时相比有较好地抑制作用,黄瓜枯萎病菌的抑制率达到65.3%,红枣链格孢菌较低仅为47.5%,纳米微粉具有抗暴晒和水浸湿能力。     

一株石韦内生真菌S-34的鉴定及其代谢物检测与分析

以药用植物有柄石韦叶为材料,采用组织块法与微量稀释法分离并筛选出一株具有抑菌活性的内生真菌S-34。经形态学观察、ITS测序与序列比对鉴定内生真菌S-34为链格孢属(Alternaria sp.)。进一步利用GC-MS对其代谢物进行检测与分析,结果显示:内生真菌S-34发酵液乙酸乙酯提取物的抑菌成分主要为氟苯甲酸(20.86%)、苯乙醇(4.89%)、2,3-丁二醇(3.64%),菌体乙酸乙酯提取物的抑菌成分主要为苯甲醛(2.27%)、亚麻醇(2.53%)、亚油酸单甘油酯(1.69%)、亚麻酰氯(9.28%)、反式角鲨烯(7.26%)、麦角甾醇(2.78%)。研究表明,有柄石韦内生真菌S-34的代谢物中蕴藏着较为丰富的抑菌活性物质,是开发天然药物的潜在资源。     

植物提取物对猕猴桃软腐病致病菌的抑制活性

目的研究4种食药两用中草药对"贵长"猕猴桃软腐病主要致病菌的抑制活性。方法以"贵长"猕猴桃为实验材料,对猕猴桃软腐病进行分离纯化鉴定,采用抑制菌丝生长速率法,并采用4种食药两用中草药粗提物对猕猴桃软腐病的抑制活性进行测试。结果从"贵长"猕猴桃软腐病中分离鉴定出灰霉菌(Botrytis cinerea)、拟茎点霉菌(Phomopsis sp.)、葡萄座腔菌(Botryosphaeria dothidea)和青霉菌(Penicillium sp.)。4种食药两用中草药粗提物在50 mg/mL时对4株致病菌都具有一定抑制活性,其中八角茴香对4株致病菌都具有较好的抑制活性。结论采用菌丝生长抑制速率法,发现八角茴香对霉菌(Botrytiscinerea)、拟茎点霉菌(Phomopsis sp.)、葡萄座腔菌(Botryosphaeria dothidea)和青霉菌(Penicillium sp.)等具有较好的抑制率。     

云南玉米穗腐病致病菌鉴定与共生群落分析

为鉴定云南玉米穗腐病主要致病菌、研究其共生真菌群落结构以及了解主要致病菌的流行特征,从云南采集病原样本进行分离纯化,对主要致病菌进行形态学鉴定和致病性测定;并对样本中真菌总DNA的rDNA-ITS序列进行SMRT测序和生物信息学分析.最后依据从文献中收集的中国21个省份穗腐病致病菌的分离鉴定结果,利用空间插值分析推测主...     

温州河道底质有机物降解菌株的筛选、发酵和应用研究

从温州市区的河道底泥中分离得到4株有机物降解菌株,经生长条件和形态学特性鉴定为酵母菌。确定菌株HD4最适生长条件为30℃,转速160r/min, pH值6.5,接种量为8.0%,其余三菌株在此条件下培养,生长良好。在此条件下培养的4菌株的混合菌液对河道有机物的去除率达到76.36%。     

Evaluation of anti‐bacterial activity of silver nanoparticles synthesised by coprophilous fungus PM0651419

The study explored biological synthesis of metallic silver nanoparticles (AgNPs) from the less explored non‐pathogenic coprophilous fungus, sterile mycelium, PM0651419 and evaluates the antimicrobial efficacy of biosynthesised AgNPs when impregnated in wound fabrics and in combination with six antimicrobial agents. AgNPs alone proved to be potent antibacterial agents and in combination they enhanced the antibacterial activity and spectrum of antibacterials used in the study against a microbiologically diverse battery of Gram positive, Gram negative and multidrug‐resistant bacteria. AgNPs impregnated on the wound dressings established their antibacterial activity by significantly reducing the bacterial load of pathogenic bacteria like Staphylococcus aureus and Bacillus subtilis e stablishing potential as effective antimicrobial wound dressings for treatment of polymicrobial wound infections. This study presents the first report on the potential of biosynthesis of AgNPs from the under explored class of coprophilous fungi. Their promise to be used in wound dressings and as potent antibacterials alone and in combination is evaluatedInspec keywords: silver, nanoparticles, nanofabrication, nanomedicine, biomedical materials, microorganisms, antibacterial activity, wounds, fabricsOther keywords: antibacterial activity, coprophilous fungus PM0651419, biological synthesis, metallic silver nanoparticles, nonpathogenic coprophilous fungus, sterile mycelium, antimicrobial efficacy, biosynthesised AgNPs, wound fabrics, microbiologically diverse battery, Gram positive bacteria, Gram negative bacteria, multidrug‐resistant bacteria, wound dressings, bacterial load, pathogenic bacteria, Staphylococcus aureus, Bacillus subtilis, polymicrobial wound infections, Ag     

Efficiency of Hydrothermal Synthesis of Nano/Microsized Copper and Study on In Vitro Antifungal Activity

In this study, the synthesis and characterization of copper nano/microparticles in the presence of (2,2′,2″,2″′-(ethane-1,2-diylbis(azanetriyl))tetraacetohydrazide) as a capping and reducing agent under hydrothermal conditions for use in biological conditions were investigated. The effects of reductant ligand/copper ion, concentration ratios, reaction temperatures, and reaction time on the various morphologies of copper nano/microparticles were studied. The obtained particles have been characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectrum analysis (EDAX), and zeta potential analysis. Further, the formation of particles with different morphologies was confirmed. The biological and antifungal effects of these selected particles were compared with those of the Bordeaux mixture. Experiments were conducted on Alternaria alternata, Alternaria solani, and Fusarium expansum as three types of phytopathogenic fungi and Penicilliums as a non-phytopathogenic fungus. The results obtained showed that not only were the nano/microparticles more effective than Bordeaux mixture in killing phytopathogenic fungi, but also these particles did not have a fungicidal effect on the non-phytopathogenic fungus, Penicillium, which is an advantage of the obtained nano/microparticles.     

Biosynthesis of silver and gold nanoparticles using Trichoderma atroviride for the biological control of Phomopsis canker disease in tea plants

The biological way of metallic nanoparticles production using ecofriendly biocontrol agents are largely used to control many plant pathogenic microorganisms in agriculture. Hence, an attempt was made to evaluate the potential of suppressive activity of nanoparticles produced by an indigenous isolate, Trichoderma atroviride against a tea pathogenic fungus namely Phomopsis theae. The presence of biosynthesised nanoparticles was primarily confirmed through ultraviolet–visible spectroscopy analysis and was characterised using X‐ray diffraction and scanning electron microscopy‐energy dispersive X‐ray analysis to delineate the size, shape and nature of particles. Further, Fourier transform infrared analysis revealed the functional biomolecules responsible for capping and stabilisation of nanoparticles. In addition, culture filtrate containing nanoparticles was subjected to invitro antifungal studies which revealed a considerable suppression on the growth of P. theae. The biosynthesised nanoparticles were found to be active even after 3 months which established and confirmed the stability. Finally, field experiments conducted with soil application and wound dressing of nanoparticles exhibited a significant reduction in canker size when plants treated with gold followed by silver nanoparticles. Similarly, improvement in leaf yield was noted in response to these treatments. The above study confirmed the efficacy of metallic nanoparticles in management of stem disease in tea plantation.Inspec keywords: diseases, gold, silver, nanoparticles, nanobiotechnology, nanofabrication, particle size, X‐ray diffraction, scanning electron microscopy, X‐ray chemical analysis, ultraviolet spectra, visible spectra, microorganisms, Fourier transform infrared spectra, molecular biophysics, antibacterial activityOther keywords: biosynthesis, silver nanoparticles, gold nanoparticles, Trichoderma atroviride, biological control, Phomopsis canker disease, tea plants, metallic nanoparticles, ecofriendly biocontrol agents, plant pathogenic microorganisms, agriculture, indigenous isolate, tea pathogenic fungus, Phomopsis theae, ultraviolet‐visible spectroscopy, X‐ray diffraction, scanning electron microscopy, energy dispersive X‐ray analysis, particle size, particle shape, Fourier transform infrared analysis, functional biomolecules, invitro antifungal study, P. theae growth, soil application, wound dressing, stem disease, Au, Ag     

Detection of inv A gene of Salmonella by DNA-gold nanoparticles biosensor and its comparison with PCR

The genus of Salmonella are very important pathogenic bacteria and their detection in medicine and food industry is of high priority. The presence of these bacteria in food is a causative agent of food poisoning. In addition to human, these organisms are infective in most animals. Salmonellosis is the most common disease caused by the organisms. Thyphoid fever occurs when some of the Salmonella organisms are not killed by the normal human immune defences after they enter the gastrointestinal tract. In this study oligonucleotide-capped gold nanoparticles (GNPs) were used in a colorimetric assay in order to detect the inv A gene of Salmonella. A 60 nucleotides sequence of inv A gene was selected, then specific primers and probes were designed. GNPs with ～20?nm diameter were modified with (alkanethiol)-31 nucleotide probes. This method relies on the hybridisation of amplified or unamplified target sequence with this probes and GNPs aggregation. Aggregation of Au-nanoparticles caused a colour change in solution and a shift in the surface plasmon absorbance. Sensitivity of this method was compared with polymerase chain reaction (PCR) method. When target DNA was amplified with PCR, this method demonstrated a greater sensitivity in comparison with agarose gel electrophoresis but its sensitivity was lower when target DNA was unamplified.     

葡萄与保鲜包装

葡萄是我国五大水果之一,其储藏保鲜对我国的葡萄产业至关重要.文章根据葡萄生理特征和环境等因素,提出了葡萄保鲜的包装技术.     

Halogenated boroxine dipotassium trioxohydroxytetrafluorotriborate K2[B3O3F4OH] inhibits emerging multidrug-resistant and β-lactamase-producing opportunistic pathogens

Abstract

Halogenated boroxine dipotassium trioxohydroxytetrafluorotriborate, K₂[B₃O₃F₄OH] (boroxine) was previously shown to be very effective in inhibition of several carcinoma cell lines, including the skin cancer. Here, we investigated its antimicrobial potential by targeting the multidrug-resistant opportunistic pathogens associated with skin and wound infections. The antimicrobial testing against eleven bacterial and four fungal species revealed good activity of boroxine against pathogenic filamentous fungi Penicillium funiculosum and Aspergillus niger (MIC₅₀ 64 and 128?µg/ml), and a moderate bioactivity against the yeast Candida albicans (MIC₅₀ 512?µg/ml). Among the tested multidrug-resistant bacteria, the best antibacterial effect, stable over a 24-h period, was observed against the methicillin-resistant Staphylococcus aureus strain (MRSA) at MIC of 1024?µg/ml. The atomic force microscopy (AFM) used to investigate the morphology of S. aureus cells revealed indentations on its cell envelope after the boroxine exposure. These results show that in addition to the antitumor effect, boroxine exerts wide spectrum antimicrobial activity, thus may help preventing the development of skin and wound-related opportunistic infections.     

Harnessing electrical energy for anti-biofilm therapies: effects of current on cell morphology and motility

ABSTRACT

Preferentially altering bacterial migration could be a successful approach for augmenting the natural wound-healing process. Inducing electrotactic behaviours through the application of physiologically safe currents is one possible strategy for altering bacterial movement. By controlling bacterial movement at the site of infection, healing times and the severity/extent of bacterial infection could be reduced. Here, we deployed microfluidics and atomic force microscopy to determine the effect of an applied electrical current on bacterial motility and cell morphology in wound pathogens namely Pseudomonas aeruginosa, Escherichia coli, and methicillin-resistant Staphylococcus aureus (MRSA). Nanoscale imaging combined with microfluidic platforms allows for the study of single-cell swimming dynamics. Current values of 0, 0.07, and 0.125 mA were applied to bacteria in suspension. E. coli exhibited an increase in directionality and a drop in mean cellular velocity across all voltages. P. aeruginosa showed a significant decrease in mean cellular velocity at 0.07 mA, while all currents increased the directionality of movement. Electrical current had no statistically significant effect on the width or length of individual bacterial cells. A better understanding of how electrical stimulation affects pathogenic bacteria at wound sites may lead to advancements in electrotherapy and help to identify new alternatives to traditional antimicrobial approaches.     

致病性鳗弧菌金属蛋白酶基因克隆及序列分析

从我国山东沿海发病的鲈鱼（Lateolabrax japonicus）分离到一株致病性鳗弧菌（Vibrio anguillarum）W-1，该菌的胞外蛋白酶活性为4226u/ml，部分纯化的胞外蛋白酶对海水养殖大菱鲆鱼有一定的毒性。应用PCR扩增，从鳗弧菌W-1染色体DNA扩增出一条长约1.925kb的特异性PCR产物，DNA序列分析表明：克隆的片段含有完整的金属蛋白酶基因阅读框，编码611个氨基酸残基的蛋白质，该金属蛋白酶基因与一株致病性鳗弧菌蛋白酶基因的核苷酸及氨基酸序列同源性为100%，而与解蛋白弧菌（V.proteolyticus)、创作弧菌（V.vulnificus）、霍乱弧菌（V.cholerae)、斑点气单胞菌（Aeromonas punctata），嗜水气单胞菌（Aeromonas hydrophila）的氨基酸序列同源性分别为73%、70%、69%、53%、51%。     

A Hierarchical 3D Nanostructured Microfluidic Device for Sensitive Detection of Pathogenic Bacteria

Efficient capture and rapid detection of pathogenic bacteria from body fluids lead to early diagnostics of bacterial infections and significantly enhance the survival rate. We propose a universal nano/microfluidic device integrated with a 3D nanostructured detection platform for sensitive and quantifiable detection of pathogenic bacteria. Surface characterization of the nanostructured detection platform confirms a uniform distribution of hierarchical 3D nano‐/microisland (NMI) structures with spatial orientation and nanorough protrusions. The hierarchical 3D NMI is the unique characteristic of the integrated device, which enables enhanced capture and quantifiable detection of bacteria via both a probe‐free and immunoaffinity detection method. As a proof of principle, we demonstrate probe‐free capture of pathogenic Escherichia coli (E. coli) and immunocapture of methicillin‐resistant‐Staphylococcus aureus (MRSA). Our device demonstrates a linear range between 50 and 10⁴ CFU mL^?1, with average efficiency of 93% and 85% for probe‐free detection of E. coli and immunoaffinity detection of MRSA, respectively. It is successfully demonstrated that the spatial orientation of 3D NMIs contributes in quantifiable detection of fluorescently labeled bacteria, while the nanorough protrusions contribute in probe‐free capture of bacteria. The ease of fabrication, integration, and implementation can inspire future point‐of‐care devices based on nanomaterial interfaces for sensitive and high‐throughput optical detection.