加压介质对蓝色犁头霉孢子存活率及甾体转化的影响

分别以N2、高纯空气[V(O2):V(N2)=21:79]和CO2为加压介质,研究高压条件下蓝色犁头霉孢子存活率的变化情况。在3种不同加压介质下,蓝色犁头霉孢子存活率显示出相同的变化规律,随压力升高,孢子存活率逐步降低;压力一定时,蓝色犁头霉孢子存活率随保压时间的延长而降低;在相同压力和保压时间下,蓝色犁头霉孢子在高纯空气中的存活率明显高于在N2和CO2中的孢子存活率,其中蓝色犁头霉孢子在CO2中的存活率始终低于其他两种加压介质;在适宜的压力和加压介质条件下,压力可显著提高蓝色犁头霉氢化可的松产量。

顶孢霉孢子悬浮液对小麦和黄瓜种子萌发及六种作物幼苗生长的影响

【目的】研究顶孢霉Ahy1对作物的安全性及生理指标的影响.【方法】采用室内生测和生理生化分析法,测定了顶孢霉(Ahy1)孢子悬浮液对小麦和黄瓜种子萌发、体内酶活性以及对6种作物幼苗生长的影响.【结果】在25℃,相对湿度75%条件下,不同浓度的悬浮液对小麦和黄瓜种子萌发及根长生长表现出高抑和低促作用;对小麦种子中4种酶的活性均有不同程度的促进作用;对黄瓜种子中SOD、POD表现为促进作用,相对抑制率分别为-82.51%和-35.96%,对CAT有明显的抑制作用,对Pro含量影响不明显.对菜豆、小麦、玉米、辣椒、茄子、黄瓜6种供试作物株高平均抑制率分别为-18.62%、-8.12%、-11.11%、-8.56%、-6.61%和-1.71%;对菜豆、小麦幼苗鲜质量的相对抑制率分别为-21.10%、-14.29%,对辣椒、菜豆、茄子和小麦干质量抑制率分别为-16.41%、-15.59%、-15.10%和-9.50%,表现促生作用,但对黄瓜和玉米的干质量表现抑制作用.【结论】Ahy1菌株不同浓度孢子悬浮液处理供试作物21d后,均未见任何发病症状,植株生长正常,对供试作物生长没有明显可见影响.

几种活性物质引起马铃薯致病疫霉孢子囊畸变的比较研究

为了获得能使马铃薯致病疫霉孢子囊发生畸变的活性物质,本试验将孢子囊悬浮液分别与不同活性物质混合培养(v/v=1∶1)后,显微镜检观察孢子囊的形态变化,并以紫外分光光度法测定受抑制后孢子囊内蛋白含量的变化,比较不同活性物质对孢子囊畸变的影响。结果显示,供试的5种活性物质中,H2O2、CuSO4溶液和W3-2菌液引起孢子囊形态发生畸变的作用强于NaCl和Na2HPO4,且随混合培养时间延长畸变率增加,但混合培养48 h与72 h之间并无显著性差异;3种物质中以H2O2的致畸作用最强,CuSO4次之,W3-2菌液最弱,3种物质分别在450μL/mL、600μg/mL和菌液原液浓度下引起孢子囊的畸变作用最强,畸变率分别为76.08%、72.0%和51.64%;此外,用H2O2、CuSO4及W3-2菌液处理后,受抑制的孢子囊内蛋白质含量分别降低了20.38%、17.58%和53.48%。本结果表明,在研制预防马铃薯晚疫病的复合生防制剂过程中,H2O2、CuSO4及W3-2菌液有很大潜力作为组成成分或增效成分添加到复合制剂中,可更加有效地防治马铃薯晚疫病。

喷雾干燥法制备活性木霉孢子粉

研究以木霉孢子萌发率和干燥效果作为检测指标,通过单因子试验明确了喷雾干燥仪的进风温度应设置在110℃以上,进料量的设置范围为5%～20%。再以助干剂种类、助干剂含量、进风温度和进料量4因素设计L9(34)正交试验,获得了喷雾干燥法制备高活性木霉孢子粉的最佳工艺组合:β-环糊精5%、进风温度110℃、进料量10%。

顶孢霉Ahy1菌株孢子乳悬剂的配方筛选

采用室内生物测定的方法,从7种食用油,5种乳化剂,5种紫外保护剂和3种抗生素中筛选适合于顶孢霉Ahy1分生孢子粉乳悬剂的助剂配方。结果表明,姜油与顶孢霉Ahy1分生孢子粉混合贮130 d,分生孢子的萌发率最高,对孢子的生物活性无明显影响。在乳化剂、紫外保护剂和抗生素的筛选中,综合与Ahy1分生孢子粉的湿润力和生物相容性,选择吐温-80与OP-10的混剂为Ahy1孢子悬浮剂的乳化剂,十二烷基硫酸钠为湿润剂,腐植酸为紫外保护剂,硫酸链霉素为抗生素。以上助剂与顶孢霉孢子粉均有良好的生物相容性。

辣椒疫霉游动孢子在不同基因型辣椒根表侵入活动的初步研究

辣椒疫病是为害辣椒的世界性、毁灭性病害。70年代以来,我国的新疆、甘肃、吉林、北京及江苏等地辣椒疫病逐年加重,造成的损失愈来愈大。以往,我国对辣椒疫病的研究主要在病原鉴定、发生规律及防治方面,对病原菌的侵入活动研究报道不多。1991～1993年,我们对辣椒疫霉游动孢子在不同基因型辣椒根表侵入活动进行了研究。 1 辣椒疫霉游动孢子在不同基因型辣椒根表侵入时间。

寡雄腐霉1×10~6孢子/g可湿性粉剂防治水稻立枯病药效试验

寡雄腐霉是一种活体微生物广谱杀菌剂,寡雄腐霉1×106孢子/g可湿性粉剂3 000倍液(1 g/m2制剂兑水3kg),于水稻1叶1心期均匀喷雾,将苗床喷透,10 d后同剂量第2次用药,对秧苗生长无不良影响,有促进秧苗生长的作用,对立枯病的防效为100%。

甘肃皇城种羊场职工吸入霉菌孢子引发呼吸道病变的调查分析

2003年3月9日下午接甘肃皇城种羊场职工医院报告,该种羊场19名职工在清理仓库霉变玉米时,发生呼吸道中毒事件.随即疾控中心召集有关人员分析讨论中毒案件,并赴兰州医学院附属医院呼吸科调查病员情况.

激光辐照在优良根霉菌株选育中的应用研究

本文报导了采用Ｈｅ－Ｎｅ和Ａｒ＋两种激光器，分别对在酿酒过程中起糖化作用的根霉菌株孢子悬浮液进行辐照，再经继代培养后，其生长速率、糖化酶活性和培养菌箱上生长情况的观察比较结果。研究表明：采用激光辐照诱变方法，能简便快捷的选育出优良根霉菌株，并在酿酒生产中获得应用，产生经济效益。

应用响应面方法优化Coniothyrium minitans固态发酵生产生物农药

利用响应面方法对固态发酵生产生物农药盾壳霉 (Coniothyriumminitans)孢子的培养基条件进行了优化研究。响应面分析结果表明 ,淀粉、尿素和KH2 PO4与Coniothyriumminitans的孢子产量存在显著的相关性 ,通过求解回归方程得到优化发酵条件 :当淀粉为 36 .4 3g L ,尿素3.91g L和KH2 PO41.0 2 g L时 ,孢子产量达到理论最大值 9.94× 10 9孢子 g麸皮 ,在摇瓶发酵条件下 ,实际最大孢子产量为 1.0 4× 10 10 孢子

Inhibition of Chlamydospore Germination and Mycelial Growth of Trichoderma spp. by Chemical Fungicides

For exploring the influences of application and residue of chemical fungi- cides on chlamydospore preparations of Trichoderma spp., the effects of seven chemical fungicides on chlamydospore germination and mycelia growth of two bio- control fungi T. harzianum 610 and T. Iongibrachiatum 758 were studied. Carben- dazim, tebuconazole and difenoconazole showed strong toxicities, thiram and car- bexin showed moderate toxicities, and metalaxyl showed Mycelia growth of the two strains was more sensitive to most tested fungicides than those of chlamydospore germination. Chlamydospore germination of 610 was more sensitive to tested fungicides than those of 758, and mycelia growth of 758 was more sensitive to most tested fungi- cides than those of 610. Among the seven fungicides, 98% carbendazim had the strongest effects （ECru values were 1.64 and 0.05μpg/ml）, and 70% pentachloroni- trobenzene had the weakest effects （EC50 values were 1.64 and 0,05 μg/ml） for chlamydospore germination and mycelia growth of 610. As for 758, 98% carbendaz- im had the strongest inhibitory effects and 95% metalaxyl had the weakest inhibitory for chlamydospore germination of 756 （EC50 values were 0.62 and 1 108.61 μg/ml respectively）, whereas 96.2% tebuconazole showed the strongest inhibitory effects for mycelia growth of 758 （EC= value was 0.32μg/ml）, and 95% metalaxyl was the weakest （EC= value was 1 206.29 μg/ml）. According to the applied concentration of different fungicides in practice, we concluded that chlamydospore preparations of 610 and 758 could not be combined with carbendazim, tebuconazole, thiram and carboxin for controlling plant diseases, and the pesticide residues to the biocontrol effects should be kept in mind. Chlamydospore preparations of 610 and 758 can be and difenoconazole for controlling plant dis- eases, 758 chlamydospore preparations and germinated chlamydospore of 610 can be combined with metalaxyl for controlling plant diseases, and pesticide residue risk was not serious.

固定化小球联合动态反应器还原水中Cr(VI)

利用包埋法将耐铬菌株——柠檬绿木霉NG01孢子固定在PVA-SA-PDA小球内,在此基础上设计动态反应器,分别探究了固定化NG01小球以及不同反应条件下动态反应器还原Cr(VI)的性能。研究结果表明,制备的固定化NG01小球直径为2~5mm,球体完整性较好,内部孢子具有活性;固定化NG01小球对Cr(VI)的还原能力远高于游离菌体,处理50mg•L-1的Cr(VI)废水可重复利用17次以上;在反应温度30°C、pH8和水力停留时间5d时,动态反应器对Cr(VI)的还原率高达97.73%。

Production of Amylase Enzyme through Solid State Fermentation by Aspergillus niger

Traditionally, coconut dregs will be used as animal feed after the extraction of coconut oil and coconut milk from the copra. This study was carried out to discover the commercial value of coconut dregs as a solid substrate in the production of amylase through solid state fermentation （SSF） since this agro-waste is fairly rich in nutrients, providing the necessary nutrients supplementation for better microbial activity to produce enzymes. In this study, amylase is to be produced from coconut dregs by Aspergillus niger through solid state fermentation （SSF）. Three parameters were covered, which are incubation time, initial moisture content of substrate and inoculum sizes. SSF was carried out by using incubator at 37 ~C to test for enzyme activity at these following parameters： incubation time： 24, 48, 72, 96 and 120 hours; substrate moisture content： 64, 66, 68, 70 and 72% （w/w）; inoculum sizes： 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mL spore suspension （5.5 × 10^6 spores/mL）. Enzyme activities were measured through the estimation of liberated reducing sugars after the assay of amylase enzyme by using DNS （3, 5 dinitrosalicylic acid） method. Highest enzyme activities were obtained at these following parameters： incubation time： 72 hours （31.76 U/gds）; initial moisture content ofsubstrate： 66% （26.66 U / gds） and inoculum sizes： 2.0 mL （30.56 U/gds）.

Fungal Population Dynamics in Ready-to-eat Salads During a Shelf-life in Italy

The aim of this work was to investigate the fungal population dynamics in ready-to-eat bagged samples of rocket （Diplotaxis spp.）, lettuce baby leaf （Lactuca sativa L.） and ＂songino＂ （Valerianella olitoria L.） during a shelf-life, in order to evaluate the effects of the storage length and season of production on the spoilage processes. The incidence of toxigenic moulds was particularity studied in order to evaluate a potential production of mycotoxins and allergenic conidia. A total of 900 samples collected from 10 Italian trademarks were analyzed at the 2nd, 5th and 8th day after the packaging in the spring and summer. A very high number of fungi was found and a great variability of moulds and yeasts at the 1 st day of sampling was observed. Regarding to season of production, any seasonal effect on the moulds and yeasts has been observed, but the moulds detected belonged to different species in relation to season. Regarding to storage length, the yeasts and moulds did not showed significant variations during a shelf-life. In relation to vegetable species, the lettuce resulted always less contaminated with respect to other salads, and the rocket presented 1-2 Log cfu/g of increasing in the level of moulds. Regarding to fungi species, the yeasts were significantly predominant respect to moulds. Finally, the toxigenic moulds Aspergillusflavus and Penicillium italicum were found in all the types of salad in the summer, and their growth during the storage at low temperature represented a potential hazard for the mycotoxins and allergenic conidia production in these commodities.

Effects of Four Chemicals on Tissue Differentiation of Lespedeza bicolor in In-vitro Culture

In order to find the optimal bacteriostatic agents and selectors and their concentrations in genetic transformation of Lespedeza bicolor with BADH as a marker gene, an resistance experiment was carried out with four chemicals, NaCl, betaine aldehyde, PEG and cefotaxime （Cef） added into the media, Different concentrations and combinations of different chemicals were added into the media in the stage of adventitious bud regeneration of cotyledonary nodes, Shoot segment multiplication, and rooting. The results showed that NaCI and betaine aldehyde could inhibit tissue differentiation of L. bicolor, and could thus be used as selectors. Furthermore, 0.8 g/L NaCI could completely inhibit the cotytedonary node differentiation and shoot segment multiplication, and 0.5 g/L NaCI was optimal for inhibition of rooting. It was also found that with the concentration increase of betaine aldehyde in media, adventitious buds regenerated from cotyledonary nodes decreased, and 1.5 g/L was confirmed to be the optimum concentration. Moreover, the mixture of 0.7 g/L NaCI and 0.3 g/L betaine aldehyde significantly inhibited shoot segment multiplication and rooting, so this mixture could be used asa selector. The Cef ex- periment showed that 200-300 mg/L C, ef in media did not inhibit significantly the regeneration of adventitious buds from cotyledonary nodes, and 100 mg/L Cef had little effect on the shoot segment multiplication and rooting.

Statistical culture-based strategies to enhance chlamydospore production by Trichoderma harzianum SH2303 in liquid fermentation

Trichoderma-based formulations are applied as commercial biocontrol agents for soil-borne plant path- ogens. Chlamydospores are active propagules in Trichoderma spp., but their production is currently limited due to a lack of optimal liquid fermentation technology. In this study, we explored response surface methodologies for opti- mizing fermentation technology in Trichoderma SH2303. Our initial studies, using the Plackett-Burman design, iden- tified cornmeal, glycerol, and initial pH levels as the most significant factors （P〈0.05） for enhancing the production of chlamydospores. Subsequently, we applied the Box-Behnken design to study the interactions between, and optimal levels of, a number of factors in chlamydospore production. These statistically predicted results indicated that the highest number of chlamydospores （3.6×108 spores/ml） would be obtained under the following condition： corn flour 62.86 g/L, glycerol 7.54 ml/L, pH 4.17, and 6-d incubation in liquid fermentation. We validated these predicted values via three repeated experiments using the optimal culture and achieved maximum chlamydospores of 4.5×108 spores/ml, which approximately a 8-fold increase in the number of chlamydospores produced by T. harzianurn SH2303 compared with that before optimization. These optimized values could help make chlamydospore production cost-efficient in the future development of novel biocontrol agents.

Transient silencing mediated by in vitro synthesized double-stranded RNA indicates that PsCdc14 is required for sporangial development in a soybean root rot pathogen

In many eukaryotic organisms, Cdcl4 phosphatase regulates multiple biological events during anaphase and is essential for mitosis. It has been shown that Cdcl4 is required for sporulation in the potato blight pathogen Phytophthora infestans; howev- er, the role that the Cdcl4 homolog （PsCdcl4） plays in the soil-borne soybean root rot pathogen P. sojae remains ambiguous. PsCdc14 is highly expressed in spornlation, zoospore, and cyst life stages, but not in vegetative mycelia and infection stages, suggesting that it contributes to asexual reproduction and thus the spread of the disease. Double-stranded RNA （dsRNA） medi- ates gene silencing, a post-transcriptional and highly conserved process in eukaryotes, involving specific gene silencing through degradation of target mRNA. We combined in vitro dsRNA synthesis and a polyethylene glycol-mediated transfor- marion system to construct a dsRNA-mediated transient gene silencing system; and then performed a functional analysis of PsCdcl4 in P. sojae. PsCdc14 mRNA was dramatically reduced in transformants after protoplasts were exposed in in vitro synthesized PsCdc14 dsRNA, resulting in low sporangial production and abnormal development in P. sojae silencing lines. Furthermore, dsRNA-mediated transient gene silencing could enable elucidation of P. sojae rapid gene function, facilitating our understanding of the development and pathogenicity mechanisms of this oomycete fungus.