Antagonizing Aspergillus parasiticus and Promoting Peanut Growth of Bacillus Isolated from Peanut Geocarposphere Soil

A set of 38 Bacillus strains isolated from peanut geocarposphere soil were screened as potential biological control agent anti-Aspergillus parasiticus. Tip-culture method with rapid and quantitative characteristics was used to determine anti-A. parasiticus activity and the process of isolation could be accelerated with this method. 12 out of 38 Bacillus strains showed high anti-alfatoxin production activity. These 12 Bacillus strains were selected to identify the characteristics of promoting peanuts germination rate. Pot experiment in greenhouse was carried out by using these strains which can promote peanuts germination. Phytohormones in the fermentation broth were also detected as another important reference factor to select the isolates as biological control agent with PGPR features. These Bacillus strains isolated from peanut geocarposphere soil not only had high ability anti-Aspergillus parasiticus, but also promoted peanut growth. Therefore, these Bacillus strains were well adapted to peanut production in the ifeld as biological control agent with plant growth promoting rhizobacteria （PGPR） features.

Saffron (<i>Crocus sativus L.</i>) Inhibits Aflatoxin B₁Production by <i>Aspergillus parasiticus</i>

Aflatoxin B1 (AFB1) is a carcinogenic metabolite produced by certain Aspergillus species. The aim of the present study was to investigate the effect of saffron stigmas on A. parasiticus growth and AFB1 production in Yeast Extract Sucrose (YES) medium. AFB1 was extracted from cultures and purified with immunoaffinity columns followed by high performance liquid chromatography (HPLC) coupled to fluorescence detector (FL) analysis. Methods' recovery and limit of detection were 95.3% and 0.02 ng AFB1·ml–1 of YES respectively. Results indicated that AFB1 production in samples of YES inoculated with A. parasiticus after the addition of saffron dried stigmas (100 mg·flask–1) was significantly lower (p 1 was detected, after the 7th day of observation in cultures with saffron alone. Maximum production was observed on the 12th day (0.018 μg AFB1·flask–1) and on the 9th day (0.051 μg AFB1·flask–1) for samples of YES with the addition of saffron inoculated with A. parasiticus and samples with saffron alone (non-inoculated), respectively. In control samples (inoculated without saffron) the maximum production on the same days 12 and 9 was 75.31 μg AFB1·flask–1 and 64 μg AFB1·flask–1 respectively. Conclusively when saffron was added to YES inoculated with A. parasiticus, AFB1 production decreased by 99.9% compared to control cultures without saffron addition. This inhibition can be attributed to the antioxidant capacity of saffron constituents.

内蒙古鸟类新纪录——短尾贼鸥Stercorarius parasiticus

2017年在内蒙古自治区兴安盟扎赉特旗图牧吉国家级自然保护区观察并拍摄记录一只短尾贼鸥(Stercorarius parasiticus)淡色型个体,为内蒙古鸟类新纪录.对该鸟的发现过程、形态特征及行为习性进行了记录和描述.

Purification and characterization of <i>Aspergillus parasiticus</i>cytosine deaminase for possible deployment in suicide gene therapy

Cytosine Deaminase (CD) from Aspergillus parasiticus was purified and characterized. Time course for maximal CD production (50 μmol/min/mg) was at 72 hrs. The enzyme was purified 387.73 folds with an overall yield of 13%. The CD had pH optimum of 7.2, a temperature optimum of 40℃ - 45℃, activation of energy (Ea) of 8.4 KJ/mol and a t1/2 of 1.10 hr. A. parasiticus CD stoichiometrically deaminated Cyto-sine and 5-fluorocytosine (5-FC) with the KM values of 0.19mM and 0.30 mM respectively. Studies on the effect of pH on KM and Vmax gave pKa1 of 5.8 and pKa2 of 6.3 with enthalpy of ionization of 43.01 KJ/mole suggesting histidine in the active site. The enzyme was strongly inhibited by Ca2+, Co2+, Zn2+ and Hg2+ and completely inhibited by Cu2+ and Fe2+ at 50 mM. Therefore, A. parasiticus CD can be compared with CDs from other sources that are used in suicide gene therapy.

Antifungal Activity against <i>Aspergillus parasiticus</i>of Supernatants from Whey Permeates Fermented with Kefir Grains

Aspergillus parasiticus, a common fungal contaminant in food, produces aflatoxin B1, which is classified as human carcinogen. Kefir is an ancient fermented beverage obtained by the fermentation of different substrates with kefir grains. A very important waste produced by the dairy cheese industry is the whey permeate, which nowadays is a strong ambient contaminant. The aim of this work was to assess the effect of whey permeates fermented with kefir grains against A. parasiticus growth, aflatoxin B1 biosynthesis, and the kefir microorganisms protection against the cell damage produced by aflatoxin B1. It was observed that kefir-cell-free-supernatants (CFS) produced fungal inhibition. A fungicidal effect was observed with 65% v/v of CFS in the culture medium (final pH 4.55 and total undissociated lactic and acetic acid concentration 34.08 mM). Under these conditions, aflatoxin production was not detected. Finally, it was found that non-viable kefir microorganisms protected HepG2 cells from the damage produced by aflatoxin B1.

Evaluation of growth characteristics of Aspergillus parasiticus inoculated in different culture media by shortwave infrared(SWIR) hyperspectral imaging

The growth characteristics of Aspergillus parasitic us incubated on two culture media were ex-amined using shortwave infrared(SWIR,1000-2500 nm)hyperspectral imaging(HSI)in this work.HSI images of the A.parasiticus colonies growing on rose bengal medium(RBM)and maize agar medium(MAM)were recorded daily for 6 days.The growth phases of A.parasiticus were indicated through the pixel number and average spectra of colonies.On score plot of the first principal component(PC1)and PC2,four growth zones with varying mycelium densities were identified.Eight characteristic wavelengths(1095,1145,1195,1279,1442,1655,1834 and 1929 nm)were selected from PC1 loading,average spectra of each colony as well as each growth zone.F urthermore,support vector machine(S VM)classifier based on the eight wavelengths was built,and the classification accuracies for the four zones(from outer to inner zones)on the colonies on RBM were 99.77%,9935%,99.75%and 99.60%and 99.77%,9939%,99.31%and 98.22%for colonies on MAM.In addition,a new score plot of PC2 and PC3 was used to differ-entiate the colonies incubated on RBM and MAM for 6 days.Then characteristic wavelengths of 1067,1195,1279,1369,1459,1694,1834 and 1929 nm were selected from the loading of PC2 and PCg.Based on them,a new SVM model was developed to diferentiate colonies on RBM and MAM with accuracy of 100.00%and 9999%,respectively.In conclusion,SWIR hyperspectral image is a powerful tool for evaluation of growth characteristics of A.parasiticus incubated in diferent culture media.

几种植物材料中总RNA的提取

用改良前后的异硫氰酸胍一步法、Trizol法和CTAB-异硫氰酸胍法,从多糖和色素较少的豌豆、水稻、构树和华南蕨绿叶,色素较多的红绒球、蟛蜞菊和红背桂花叶,以及富含多糖的香蕉果肉等几种植物材料中提取RNA。发现一步法对豌豆、水稻和蟛蜞菊叶片总RNA的提取均有很好的效果。Trizol法也有好的效果,但如果提取缓冲液的pH达6.0,提取的RNA便有DNA的污染,且该污染随pH增加而增加。对于富含多糖的香蕉果肉,一步法和CTAB异硫氰酸胍法的效果均不理想;改良后的一步法中增加了乙醚去除多糖并获得了较好的效果。本文还提出了判断RNA的质量的标准。

华南毛蕨内生真菌抑菌活性筛选及活性菌株Pestalotiopsis sp. CYC38代谢产物的研究

目的筛选具有抑菌活性的华南毛蕨内生真菌及分析其中1株活性较强的菌株的代谢产物。方法以敏感型金黄色葡萄球菌、耐药型金黄色葡萄球菌、大肠埃希菌、铜绿假单胞菌为供试指示菌,采用琼脂块法对43株内生真菌进行抑菌活性筛选,以Pestalotiopsis sp.CYC38作为目标菌株,对其次级代谢产物进行分离,并采用波谱学分析手段鉴定化合物结构。结果 43株内生真菌中有19株菌株至少对1种指示菌有抑菌作用,占分离菌株总数的44%;从高活性菌株CYC38的发酵产物中分离到2个化合物,分别鉴定为啤酒甾醇和1-(4-羟基苯基)-2氨基乙醇。结论华南毛蕨内生真菌具有较好的抗菌活性,且对耐药型金黄色葡萄球菌也表现出良好的抑制作用,该结果为开发新型的抗耐药菌药物提供基础。

黄曲霉和寄生曲霉pksA基因部分序列的同源性分析

比较寄生曲霉和黄曲霉pksA基因部分序列同源性。方法:采用RT-PCR从寄生曲霉AS3.4407和黄曲霉菌AS3.4409中克隆得到pksA基因部分序列,经克隆后测序。结果:通过比对分析发现该两株菌pksA基因同源性可达98.0%。

Cancer and Infectious Causes

Various kinds of organisms, including viruses, bacteria, trematodes and fungi are known carcinogens that cause cancer. Infectious identification related to cancer may lead to better treatment for both the prevention and targeting of cancer therapy. Although nearly 20% of all cancers are caused by an infection of a microbe, the amount of evidence and information regarding the mechanisms associated with oncogenesis varies dramatically from one organism to the next. This review cannot be exhaustive because we are not aware of all infections worldwide in addition to their potential mechanisms for oncogenesis. More research is required for all of the species mentioned in this review.

Application of Whey Permeate Fermented with Kefir Grains for the Shelf-Life Improvement of Food and Feed

Fungal contamination by Aspergillus parasiticus and A. flavus causes negative effects on the production of food cereals. Kefir is an ancient fermented beverage obtained by the fermentation of different substrates with kefir grains. An important waste produced by the dairy cheese industry is the whey permeate, which nowadays is a strong ambient contaminant. The aim of this work was the standardization of the whey permeate fermenting conditions with kefir grains, the assessment of the antifungal activity of the cell-free-supernatants (CFS) from these fermentations and to compare it with that obtained with CFS of milk fermented with kefir grains. Finally, we studied if the addition of kefir fermented whey permeate to food (bread) and feed (poultry) could produce shelf life improvement. The optimal condition to obtain CFS with fungicidal effect was a fermentation with 10% w/v of kefir grains, at 30°C, for 24 hours until a pH 3.7. We found that CFS from whey permeate caused fungal inhibition, whereas CFS of kefir grains grown in milk showed lower antifungal activity. Additionally, the addition of kefir-fermented whey permeates in food (bread) and feed (poultry) improved their resistance to fungal contamination. This is the first report about the application of kefir-fermented whey permeate to improve the shelf life, suggesting its potential use as a biopreservative.

华南毛蕨挥发油对美洲斑潜蝇成虫的行为干扰作用

利用气相色谱-质谱连用仪,对华南毛蕨Cyclosorusparasiticus挥发油成分进行分析.结果表明,华南毛蕨挥发油中含有38种化学成分,酯类物质占21 961%,酸类占17 199%,烯醇类占16 161%,酚类物质占14 263%,醛酮类占11 026%,其中,对昆虫具有驱避作用的糠醛占2 943%,香豆素占1 327%,丁二酸二异丁酯占1 126%.对挥发油进行生物测定的试验结果表明,2 5、5 0、7 5、10 0μL用量对美洲斑潜蝇成虫产卵在施用24h有驱避作用同时表现出一定的拒食作用,其产卵驱避和拒食作用的大小随施用剂量的增加而增大,随时间的增长而逐渐减弱;施用48h后仅10 0μL有产卵驱避作用和拒食作用.采用四臂嗅觉仪对美洲斑潜蝇成虫的行为反应测定结果也表明,其对这种挥发油具有同样的行为趋向.

寄生曲霉产生絮凝剂的培养条件及其絮凝特性

从霉菌中筛选得到一株絮凝性较强的寄生曲霉（Ａｓｐｅｒｇｉｌｕｓｐａｒａｓｉｔｉｃｕｓ）．通过条件试验，确定寄生曲霉产生絮凝剂的最佳条件为：蔗糖作碳源，ＮａＮＯ３或脲或谷氨酸作氮源，初始ｐＨ为３．０，温度为２８℃，摇床的转速为１４０ｒ／ｍｉｎ．寄生曲霉在酸性条件下对高岭土具有很强的絮凝性，且有较高的热稳定性．

微波杀灭霉变玉米中寄生曲霉动力学模型

为描述微波对霉菌的杀菌过程和预测杀菌效果,建立了微波对霉变玉米中寄生曲霉孢子的杀菌动力学模型。在50～75℃的微波加热条件下获得了寄生曲霉孢子的致死曲线。选取线性模型、Weibull模型和Weibull简化模型来拟合微波杀菌的动力学过程,以决定系数、均方误差、精确因子和偏差因子作为模型拟合度优劣的评判指标。结果表明,Weibull模型较线性模型能更好地拟合微波处理下寄生曲霉孢子失活动力学变化;Weibull模型简化后与原模型具有相似的拟合性,可有效预测特定温度-时间组合下的微波灭菌效果;通过Weibull模型预测微波杀菌时间可避免线性模型导致的杀菌不彻底或者过度杀菌的现象。

黄曲霉毒素生物防控菌的筛选及鉴定

筛选黄曲霉毒素生物防控菌,为黄曲霉毒素的生物防控提供支持。以花生原产地土壤为材料,采用牛津杯法筛选所需菌株。对筛选出的拮抗菌株进行抑制产毒曲霉菌株的生长、产孢、降解黄曲霉毒素实验。筛选出2株黄曲霉毒素生防细菌,编号21-1-2、17-3,经鉴定,拮抗菌21-1-2为枯草芽胞杆菌,拮抗菌17-3为地衣芽胞杆菌。分别对拮抗菌对曲霉孢子萌发的抑制、抑制黄曲霉的生长和菌丝延长以及减少黄曲霉毒素的产生、对黄曲霉毒素的分解作用等几个方面进行研究,结果表明,拮抗菌可以明显抑制产毒曲霉孢子的萌发、生长、菌丝的延长,减少黄曲霉毒素的产生以及分解黄曲霉毒素。

一株亚硝酸盐降解真菌Aspergillus parasiticus JFS的筛选及鉴定

【目的】筛选可降解亚硝酸盐的菌株。【方法】利用亚硝酸盐选择培养基从水样、土样、朽木等20多个样品中筛选目的菌株。利用盐酸萘乙二胺法检测目的菌株在亚硝酸盐液体培养基中降解亚硝酸盐的能力,利用镉柱还原法和试纸法鉴定亚硝酸盐被目的菌株代谢后的产物;利用菌落形态、菌丝及分生孢子形态、ITS DNA序列、β-Tubulin gene序列及Calmodulin gene序列分析等鉴定目的菌株。【结果】得到一株可强烈降解亚硝酸盐的真菌菌株JFS,其能在亚硝酸盐浓度高达20.0 g/L的液体培养基中很好的生长,菌株JFS将亚硝酸盐降解为无毒的硝酸盐和铵根离子。结合形态学、对培养基的要求及上述3个基因序列的进化树分析,该菌株属于寄生曲霉菌(Aspergillus parasiticus)。【结论】菌株JFS具有强烈的降解亚硝酸盐的能力。

桑寄生对桂花和阴香营养代谢的影响

采集被桑寄生严重危害的桂花和阴香样品,以同一植株没有被桑寄生危害的枝条作为对照,分析叶片中的叶绿素、可溶性总糖和脯氨酸的含量。结果发现,桂花和阴香被桑寄生侵害后,叶片中的叶绿素及可溶性糖含量下降,光合作用受阻,脯氨酸含量有所上升。通过试验数据的对比分析,阐明桑寄生对桂花和阴香营养代谢的影响,并提出了园林树木保护的若干建议和措施。

花生黄曲霉毒素产毒菌种群区系和地理分布

花生是我国重要的食油兼用作物,黄曲霉及其毒素分布广、危害大,可贯穿田间、储藏、加工、流通多环节,是威胁花生质量安全的主要风险因子之一。土壤黄曲霉菌和寄生曲霉菌是花生感染产毒的主要源头,系统研究花生田间黄曲霉菌和寄生曲霉菌的分布,对开展花生黄曲霉毒素污染预警和绿色防控意义重大。本文重点研究论述了花生田间黄曲霉菌和寄生曲霉菌分布的影响因素和种群生物地理分布特征等,提出了当前土壤黄曲霉菌和寄生曲霉菌分布研究中存在的问题和未来重点研究方向。

桑生除痹合剂对兔膝骨性关节炎组织形态学和血液流变学的影响

目的观察桑生除痹合剂对膝骨性关节炎家兔组织形态学和血液流变学的影响。方法将健康6月龄新西兰大白兔36只,随机分为正常组,模型组,壮骨关节丸组,桑生除痹合剂高、中、低剂量组。每组6只,按照Hulth方法造模,分别灌服高、中、低剂量桑生除痹合剂,壮骨关节丸组灌服壮骨关节丸。12周后,测定血液流变学指标再处死动物,取股骨内侧髁关节负重区软骨及膝关节滑膜标本行光镜观察。结果关节软骨及滑膜标本光镜下呈显著退变表现;壮骨关节丸组和桑生除痹合剂高、中、低剂量组全血黏度、全血还原黏度、血浆黏度及红细胞聚集指数与模型组比较差异有统计学意义(P<0.01)。结论从关节软骨及滑膜的光镜观察可以判断,兔膝骨性关节炎模型建立成功;桑生除痹合剂能明显改善血液流变学状态,改善局部血液循环,延缓软骨退化。

基因芯片在黄曲霉毒素生物合成相关基因差异表达分析中的应用研究

为寻找与黄曲霉毒素生物合成密切相关的基因,本研究采用诱导产毒培养的方法培养寄生曲霉AS3.4407,获得产毒与不产毒两种性状的菌丝体。应用基因芯片技术和RT-PCR方法筛选与黄曲霉毒素生物合成相关的差异表达基因。研究结果表明产毒菌丝与不产毒菌丝中与产毒相关的部分基因存在差异表达。芯片扫描的结果与RT-PCR的扩增结果一致,均显示有6个基因存在表达差异,它们分别是aflA、aflE、aflF、aflR、aflT和aflX。本研究证实aflR基因表达的改变与黄曲霉毒素的产生密切相关。