柑橘溃疡病拮抗菌的分离筛选及其田间防效

从湖南衡阳、常德、长沙、永州等地的柑橘园采集标本,分离、筛选柑橘叶表微生物,共分离到225株细菌,9株真菌.平板拮抗试验结果表明,其中6个菌株有较好的防效,占分离菌株的13.7%.通过对菌株过滤液和定殖力的测定,菌株Kx15和Kx48效果明显,在温室对柑橘溃疡病的防治效果分别达到45.6%和55.6%,在重病果园中的防治效果分别为40.3%,47.7%,且Kx48要优于Kx15.菌株Kx15初步鉴定属于葡萄糖杆菌属,Kx48属于乳酸杆菌属.     

水蜜桃采后生物保鲜初步研究

通过对不同生防菌、储存温度、1-MCP的组合条件和生防菌在水蜜桃表面的定殖情况与水蜜桃采后保鲜的效果关系的研究,探讨水蜜桃生物防腐保鲜的技术和方法.结果表明,使用荧光假单胞杆菌2P24和1-MCP组合处理,防腐保鲜效果最好.对照在保藏3d时病情指数达到16.7％,基本失去了商品价值,而采用荧光假单胞杆菌2P24和1-M...     

大豆疫霉慢生长菌株HN-1的生物学特性及传染规律

观察和测定了大豆疫霉(Phytophthora sojae)慢生长菌株HN-1及其单游动孢子后代的培养性状及致病力,并将其与正常生长的其他3个菌株进行对峙培养,研究其慢生长特性传染规律,测定受感染菌株的培养特性及致病力.结果表明,大豆疫霉慢生长菌株HN-1的培养特性与正常菌株相比生长显著缓慢,菌落形态有明显差异,卵孢子产生量低,对大豆幼苗的致病力显著较弱;该菌的慢生长特性可通过无性繁殖传递至子代,并可通过对峙培养传染至其他正常生长菌株,传染后产生的受染菌株表现慢生长特性且致病力减弱.     

防治胡椒瘟病生物农药筛选及其盆栽药效试验

胡椒瘟病是危害中国胡椒产业的首要病害,目前主要依赖使用化学农药防治,筛选应用生物农药是减少化学农药用量的有效途径。本文通过室内毒力测定和室外盆栽药效试验,测定了5种生物农药对胡椒瘟病的防治效果。结果表明:室内毒力测定木霉菌WP、枯草芽孢杆菌WP和Z菌株发酵液对胡椒瘟病病原菌的抑菌效果好且敏感性高,EC50分别为0.49、0.78、1.13μg/m L;盆栽药效试验Z菌株发酵液和枯草芽孢杆菌WP对胡椒瘟病防效最好,平均防效分别为83%和82%,芽孢杆菌/淡紫拟青霉WP的防效次之,平均防效为69%。综合来看,Z菌株发酵液和枯草芽孢杆菌WP对胡椒瘟病具有很好防效,具备良好的绿色防控潜力。     

4种常用农药对2种天敌蝽的药害影响

笔者探究了4种不同农药对两种蝽的药害影响,结果表明：氯氰、辛硫磷、吡虫啉、氰戊菊杀虫剂对2种蝽（蠋蝽和一种益蝽）皆有较强药害,释放于自然环境后该2种天敌蝽存活与繁殖受到明显抑制;除草剂类农药虽然对2种天敌蝽没有直接药害影响,但施用除草剂后对自然环境中的农作物具有毒性作用,2种蝽的存活与繁殖同样受到影响。因此,要2种蝽在自然环境中得以较好生存与自然繁殖,必须规范释放地区的农药管理,加强绿色环保理念教育与引导,才能建设稳定的立体生防系统。     

Micrometam C Protects against Oxidative Stress in Inflammation Models in Zebrafish and RAW264.7 Macrophages

Micrometam C is a core of novel marine compound isolated from the mangrove associates Micromelum falcatum. In this study, we investigated the protective effects of micrometam C in inflammation models in the transgenic zebrafish line Tg (corola: eGFP) and RAW264.7 macrophages. We found that micrometam C significantly suppressed the migration of immune cells in tail-cutting-induced inflammation in transgenic zebrafish and reduced lipopolysaccharide (LPS)-induced reactive oxygen species (ROS) in both zebrafish and macrophages. In addition, micrometam C also restored LPS-induced reduction of endogenous antioxidants, such as catalase (CAT), glutathione (GSH) and superoxide dismutase (SOD). The protective effects of micrometam C were in parallel to its inhibition of NADPH oxidase and nuclear factor-kappa-binding (NF-κB) activity. Thus, the present results demonstrate that micrometam C protects against LPS-induced inflammation possibly through its antioxidant property.     

Morphological and Proteomic Analyses Reveal that Unsaturated Guluronate Oligosaccharide Modulates Multiple Functional Pathways in Murine Macrophage RAW264.7 Cells

Alginate is a natural polysaccharide extracted from various species of marine brown algae. Alginate-derived guluronate oligosaccharide (GOS) obtained by enzymatic depolymerization has various pharmacological functions. Previous studies have demonstrated that GOS can trigger the production of inducible nitric oxide synthase (iNOS)/nitric oxide (NO), reactive oxygen species (ROS) and tumor necrosis factor (TNF)-α by macrophages and that it is involved in the nuclear factor (NF)-κB and mitogen-activated protein (MAP) kinase signaling pathways. To expand upon the current knowledge regarding the molecular mechanisms associated with the GOS-induced immune response in macrophages, comparative proteomic analysis was employed together with two-dimensional electrophoresis (2-DE), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/TOF MS) and Western blot verification. Proteins showing significant differences in expression in GOS-treated cells were categorized into multiple functional pathways, including the NF-κB signaling pathway and pathways involved in inflammation, antioxidant activity, glycolysis, cytoskeletal processes and translational elongation. Moreover, GOS-stimulated changes in the morphologies and actin cytoskeleton organization of RAW264.7 cells were also investigated as possible adaptations to GOS. This study is the first to reveal GOS as a promising agent that can modulate the proper balance between the pro- and anti-inflammatory immune responses, and it provides new insights into pharmaceutical applications of polysaccharides.     

Epipolythiodiketopiperazines from the Marine Derived Fungus Dichotomomyces cejpii with NF-κB Inhibitory Potential

The Ascomycota Dichotomomyces cejpii was isolated from the marine sponge Callyspongia cf. C. flammea. A new gliotoxin derivative, 6-acetylmonodethiogliotoxin (1) was obtained from fungal extracts. Compounds 2 and 3, methylthio-gliotoxin derivatives were formerly only known as semi-synthetic compounds and are here described as natural products. Additionally the polyketide heveadride (4) was isolated. Compounds 1, 2 and 4 dose-dependently down-regulated TNFα-induced NF-κB activity in human chronic myeloid leukemia cells with IC_50s of 38.5 ± 1.2 µM, 65.7 ± 2.0 µM and 82.7 ± 11.3 µM, respectively. The molecular mechanism was studied with the most potent compound 1 and results indicate downstream inhibitory effects targeting binding of NF-κB to DNA. Compound 1 thus demonstrates potential of epimonothiodiketopiperazine-derived compounds for the development of NF-κB inhibitors.