Two Novel Hepatocellular Carcinoma Cycle Inhibitory Cyclodepsipeptides from a Hydrothermal Vent Crab-Associated Fungus Aspergillus clavatus C2WU

Two novel cyclodepsipeptides containing an unusual anthranilic acid dimer and a d-phenyllactic acid residues, clavatustides A (1) and B (2), were identified from cultured mycelia and broth of Aspergillus clavatus C2WU isolated from Xenograpsus testudinatus, which lives at extreme, toxic habitat around the sulphur-rich hydrothermal vents in Taiwan Kueishantao. This is the first example of cyclopeptides containing an anthranilic acid dimer in natural products, and the first report of microbial secondary metabolites from the hydrothermal vent crab. Clavatustides A (1) and B (2) suppressed the proliferation of hepatocellular carcinoma (HCC) cell lines (HepG2, SMMC-7721 and Bel-7402) in a dose-dependent manner, and induced an accumulation of HepG2 cells in G1 phase and reduction of cells in S phase.     

黑曲霉M10对采后砀山酥梨腐烂的影响

[目的]分析黑曲霉M10侵染砀山酥梨过程。[方法]通过不同接种方式、不同接种量对酥梨进行黑曲霉M10侵染,比较酥梨腐烂情况,考查温度对黑曲霉侵染酥梨效果的影响。[结果]损伤接种侵染效果明显,当接种浓度大于1×102个/ml时,酥梨发病率为100%;温度超过10℃时,砀山酥梨易受黑曲霉M10的侵染。[结论]明确了黑曲霉M10对砀山酥梨侵染过程,为防治砀山酥梨的贮藏病害提供理论依据。     

Use of two fungal species to induce agarwood resin formation in Gyrinops walla

Gyrinops walla Gaertn. is the only species growing in Sri Lanka that belongs to the agarwood family,Thymelaeaceae. Although agarwood resin induction and extraction from Aquilaria species of the same family have been practised for many decades in Southeast Asian region,the ability of producing agarwood resins in G. walla was discovered recently. Since previous studies were on agarwood resins formed due to natural causes, the present study was conducted to identify the potential fungal species that are capable of artificially inducing agarwood resin formation in G. walla. Since this is the first ever study conducted on artificial inducement of agarwood resin formation in G.walla, Aspergillus niger and Fusarium solani were selected owing to their high abundance in the naturally formed agarwood resinous tissues collected from 25 G. walla trees.Both fungal species were separately grown in yeast extract glucose agar and used to inoculate healthy G. walla trees under aseptic conditions. Three holes were made for each tree and 2 g of fungal culture including the medium were placed in each hole. Tissue discoloration, characteristic aroma, resin content and resin constituents were checked at10 cm intervals above and below the inoculation points for a period of 1 year. Results revealed that tissue discoloration and resin content were higher in the trees inoculated with A. niger. Other than at 10 cm above and below the inoculation points, samples collected at all locations had significantly higher resin contents when inoculated with A. niger compared to F. solani. Sixteen agarwood resin constituents, which were also recorded in Aquilaria species, were identified from the discolored tissues using GC–MS analysis. Jinkohol, agarospirol and 2(2-phenyl)chromone derivatives were found in all discolored tissues collected at 10-cm intervals of the trees inoculated with both fungi. b-Seline, c-eudesmol and valerenal were found in nine of 10 sample points on the stem. c-Elemene was recorded only in one sample. The characteristic aroma during burning was stronger for dark-colored tissues than the light-colored ones. The present study confirmed the potential use of certain fungal species to induce agarwood resin in G. walla and that A. niger is more effective than F.solani.     

芦丁及芦丁金属配合物对木材霉菌的抑菌性初探

为探究新型木材防霉剂,采用抑菌圈法、载片观察法及木材防霉试验,探究芦丁及芦丁不同金属配合物对黑曲霉的抑菌效果。结果表明,芦丁-锰、芦丁-镁、芦丁-锌可以减少黑曲霉的菌丝数量,影响孢子的产生和成熟,对黑曲霉具有明显的抑制作用;芦丁、芦丁-铜、芦丁-铁可以影响黑曲霉的菌丝生长,但是对孢子的产生和成熟的影响较小,对黑曲霉的抑制作用不明显。浓度为1.6mg·mL-1的芦丁-锰、芦丁-镁、芦丁-锌浸注处理毛白杨的侵染值分别为0.67、1.33和1.50;芦丁、芦丁-铜、芦丁-铁浸注处理毛白杨的侵染值分别为2.33、2.50和3.33。芦丁-锰、芦丁-镁、芦丁-锌对黑曲霉具有较好的抑制效果,可用于制备木材防霉剂。本试验结果为芦丁金属配合物制备环保型木材防霉剂提供一定的理论依据。     

吡咯伯克霍尔德菌WY6-5产二甲基二硫对储藏期花生黄曲霉及毒素的抑制作用

【目的】验证吡咯伯克霍尔德菌（Burkholderia pyrrocinia）WY6-5的抑菌作用,评价其对储藏期花生黄曲霉（Aspergillus flavus）及毒素的防治效果,分析抑菌作用机制,鉴定活性物质,并检测其最低抑菌浓度,为储藏期真菌病害及毒素的防控提供新材料。【方法】采用非接触培养皿对扣培养法,检测菌株WY6-5对黄曲霉的抑制效果,添加活性炭,验证挥发性物质的抑菌作用;密闭储藏环境,检测WY6-5产二甲基二硫对花生黄曲霉及毒素的抑制效果;收集处理后的花生籽粒,锇酸固定,并进行扫描电镜观察,检测黄曲霉细胞显微结构变化,通过透射电镜观察,检测黄曲霉细胞内部结构的显微差异;购买活性物质标准品,梯度稀释,与黄曲霉菌丝和孢子对扣培养,分析最低抑菌浓度。【结果】吡咯伯克霍尔德菌WY6-5分离自茶园根际土壤,可产生挥发性物质二甲基二硫,并高效抑制黄曲霉的生长,抑菌率达95%以上;同时,在高水活度（a_w）条件下,WY6-5还可抑制储藏期花生黄曲霉和毒素污染;两种水活度下,对照组中发病率高达100%,黄曲霉毒素总含量分别为399.32 μg?kg ^-1（a_w 0.859）和3 143.19 μg?kg ^-1（a_w 0.923）;WY6-5添加组,花生黄曲霉发病率降为2%（a_w 0.859）与21%（a_w 0.923）,毒素含量降为4.86 μg?kg ^-1（a_w 0.859）和121.37 μg?kg ^-1（a_w 0.923）,与对照组相比,对毒素的抑制率达98.78%和96.14%。扫描电镜观察显示,WY6-5产生的挥发性气体能抑制黄曲霉孢子的萌发,透射电镜显示,黄曲霉细胞结构未呈现明显损伤。挥发性物质二甲基二硫抑菌作用明显,对黄曲霉菌丝生长的最低抑菌浓度为100 μL?L ^-1(物质体积/培养体积),对孢子萌发的最低抑菌浓度为50 μL?L ^-1(物质体积/培养体积)。【结论】吡咯伯克霍尔德菌WY6-5可产生高效抑菌挥发物二甲基二硫,在低浓度下即可完全抑制黄曲霉菌丝生长和孢子萌发,并能抑制储藏期花生黄曲霉的侵染和黄曲霉毒素的产生,为储藏期真菌病害及毒素的防控提供了新型生物材料。     

花生荚壳抗黄曲霉菌侵染的鉴定方法研究及抗性种质发掘

        黄曲霉毒素污染是影响花生食用安全性和制约产业发展的重要因素。荚壳是花生抵御黄曲霉菌侵染的第一道防线,为建立花生荚壳抗黄曲霉侵染的鉴定方法,本研究利用强侵染黄曲霉菌AF2202接种花生荚果,通过对不同接种菌浓度和培养时间的比较分析,发现接种浓度为2 ×106孢子/mL、培养7d的组合方案可以有效区分花生荚壳对黄曲霉菌侵染的抗性。利用所建立的鉴定方法对276份遗传变异丰富的花生核心种质材料进行接种鉴定,进一步证明了这一方法鉴定花生荚壳抗性的有效性和实用性,初步发掘出2份具有荚壳抗性的特异花生种质。     

Inhibitory Effect of Dimethyl Disulfide from Burkholderia pyrrocinia WY6-5 on Aspergillus flavus and Aflatoxins in Peanuts During Storage Period

【Objective】The objective of this study is to verify the antifungal effect of Burkholderia pyrrocinia WY6-5, evaluate its control efficacy against Aspergillus flavus and aflatoxins in peanuts during storage period, analyze the inhibitory mechanism, identify antifungal volatiles and detect the minimal inhibitory concentration to A. flavus, so as to provide novel strategies for the prevention and control of fungal diseases and mycotoxin during storage period.【Method】Face-to-face dual cultural test was conducted to analyze the antifungal activity of volatiles from WY6-5. Active charcoal as volatile adsorbent was added into the tests to verify the antifungal activity of volatiles. Dimethyl disulfide (DMDS) emitted form strain WY6-5 was challenged with peanut kernels inoculated with A. flavus conidia in sealed airspace without physical contact. A. flavus cells on peanut coat were collected, fixed in osmic acid, and analyzed through scanning electron microscope (SEM). Transmission electron microscope (TEM) was used to test the inner structure of A. flavus cell affected by volatiles from WY6-5. The commercial DMDS was purchased, serially diluted, and co-cultured with A. flavus conidia and mycelia to detect the minimal inhibitory concentration, respectively.【Result】B. pyrrocinia WY6-5 isolated from rhizosphere soil of tea plants could produce volatile DMDS, prevent the growth of A. flavus mycelia, the inhibition rate was over 95%. Additionally, under the condition of high water activity (a_w), WY6-5 could also inhibit the A. flavus infection and aflatoxins production in peanuts during storage period. In peanuts of control treatment, the disease incidence was 100%, and the total concentration of aflatoxins was 399.32 μg?kg ^-1 (a_w 0.859) and 3 143.19 μg?kg ^-1 (a_w 0.923), respectively. When WY6-5 was added in the treatment, the disease incidence decreased to 2% (a_w 0.859) and 21% (a_w 0.923), respectively. The concentration of aflatoxins decreased to 4.86 μg?kg ^-1 (a_w 0.859) and 121.37 μg?kg ^-1 (a_w 0.923), respectively. The inhibition rate of WY6-5 against aflatoxins contamination was 98.78% and 96.14% compared to the control treatment. SEM analysis proved that DMDS from WY6-5 inhibited the germination of A. flavus conidia. TEM analysis further proved that the inner cell structures of A. flavus conidia were not severely damaged by volatiles. Volatile DMDS showed great antifungal activity. The minimal inhibitory concentration against mycelia growth was 100 μL?L ^-1(compound volume/airspace volume). The minimal inhibitory concentration against conidia germination was 50 μL?L ^-1(compound volume/airspace volume). 【Conclusion】 B. pyrrocinia WY6-5 can produce valid antifungal volatile DMDS, which can completely inhibit the mycelia growth and conidia germination of A. flavus at low concentration, and greatly prevent the development of A. flavus disease and aflatoxins contamination in peanuts during storage period. WY6-5 and the produced DMDS provide novel bio-active agents for fungal diseases control and mycotoxins during storage period.     

利用废菌渣生产单细胞蛋白饲料研究

本文以废菌渣为主要原料,利用酿酒酵母(Saccharomyces cerevisiae)和黑曲霉(Aspergillus niger)两菌株进行混合固态发酵生产单细胞蛋白饲料.通过单因素试验和正交试验确定最佳培养条件.结果表明,各因素对粗蛋白质含量的影响为废菌渣与麸皮的比例>培养时间>氮源>水料比;混茵固态发酵的最佳培养条件为废茵渣80%:麸皮20%,硝酸铵2%.尿素1%,KH2PO4 2%,MgSO4·7H2O 1%,水料比为2.5:1,pH为4,接种量为20%,培养时间为120 h时,此时粗蛋白质含量最高,由发酵前的9.61%提高到23.28%.     

烟曲霉感染对肉鸡部分免疫指标的影响

为了研究烟曲霉感染对肉鸡血清免疫球蛋白(Ig)、γ干扰素(IFN-γ)浓度及传染性法氏囊病(IBD)抗体效价的影响,选用96只15日龄罗斯308肉鸡,随机分成试验组和对照组,每组4个重复,每个重复12只鸡。试验组连续滴注霉菌孢子5 d,对照组滴注生理盐水。试验后的第3、4和5天,分别从试验组和对照组每个重复随机抽出2只鸡进行剖检诊断和实验室检测;试验后的第7 (21日龄)和14天(28日龄),分别检测肉鸡血清中Ig A、Ig G、Ig M、IFN-γ和IBD抗体水平。结果:试验后的第3～5天,试验组鸡血液中均分离到烟曲霉;试验组鸡血清中Ig A、Ig G和Ig M浓度均极显著低于对照组(P<0. 01),血清中IFN-γ的浓度极显著高于对照组(P<0. 01),血清中IBD抗体效价极显著低于对照组(P<0. 01)。研究表明烟曲霉菌感染能显著降低肉鸡的免疫功能。