柑橘采后绿霉病生防酵母菌的筛选、鉴定及其生防效果研究

【目的】筛选能有效防治柑橘采后绿霉病菌(Penicillium digitatum)的拮抗酵母菌,为柑橘的采后保鲜提供参考。【方法】从园艺果园采集不同的水果样品,用稀释平板法分离筛选生防酵母菌株,并进行鉴定;采用PDB液体培养试验和刺伤接种的方法,研究不同浓度酵母菌悬浮液对离体和活体柑橘绿霉病菌的防治效果。【结果】获得1株拮抗酵母菌HP-10,结合生理生化特性及18S rDNA序列同源性分析,将其鉴定为马克斯克鲁维酵母(Kluyveromyces ma-rxianus)。离体和活体抑菌试验表明,菌株HP-10悬浮液能有效抑制绿霉病菌孢子的萌发;用108CFU/mL HP-10悬浮液处理病原菌孢子时,其萌发率仅为3.61%,而对照的萌发率为88.06%;25℃条件下,用108CFU/mL的酵母悬浮液处理柑橘果实2 d后,发病率仅为6.67%,病斑直径仅为2.14 mm,显著低于对照的发病率(93.33%)和病斑直径(53.31mm)。【结论】不同浓度HP-10菌悬液对柑橘绿霉病菌均具有一定的防治效果,表现出良好的生防潜力。     

梅林青霉液态发酵生产纤维素酶条件的研究

研究不同培养条件对梅林青霉液体发酵产纤维素酶的影响,为此对不同碳源、氮源、pH、培养温度、摇瓶转速和摇瓶装量、发酵时间培养条件下羧甲基纤维素酶、滤纸酶、β-葡萄糖苷酶活力进行了测定.结果表明,碳源麦麸诱导效果好于稻草、玉米秸、羊草;氮源中尿素明显降低β-葡萄糖苷酶活力,豆饼、硝酸钠和蛋白胨之间影响不明显;28℃和pH5.0是产纤维素酶最佳温度与酸碱度;通过响应面与等值线分析可知,在摇床转速170～180 r·min-1,摇瓶装量30～40 mL时,羧甲基纤维素酶、β-葡萄糖苷酶显示较高活性;摇床转速140～150 r·min-1,摇瓶装量40～50 mL时,滤纸酶显示较高活性;梅林青霉在Bioengineering的NLF19生物反应器液体发酵大约11 d时3种酶活力达到最高.     

醚菌酯对百合鳞茎青霉病的控制

采用醚菌酯浸泡兰州百合青霉病的研究结果表明:在25~100 mg/L处理浓度范围内,醚菌酯可明显降低损伤接种圆弧青霉(Penicillium cyclopium)在百合鳞片体内的扩展,其中以50 mg/L处理的效果最好,100 mg/L和125mg/L处理均造成了一定程度的药害.不同温度处理结果显示,40℃的醚菌酯处理效果优于其他温度处理,50℃和60℃处理均产生了严重的烫伤.损伤接种与药物处理的间隔时间也会对处理结果造成一定的影响.     

21种植物提取物对3种柑桔病原真菌抑菌活性的初步研究

采用菌丝生长速率法测定油茶籽等21种植物甲醇提取物对柑桔青霉病菌、柑桔绿霉病菌和柑桔酸腐病菌的抑菌活性.结果表明,对柑桔酸腐病菌抑菌活性较高的是油茶籽、甘草、桃花心木和水茄提取物,以含干粉10 mg·mL-1处理后5 d抑菌率分别为96.96%、76.44%、82.73%和69.60%.对柑桔青霉病菌抑菌率达70%以上的有油茶籽、海芋、山菅兰、水茄、上海叶冬青等的提取物,对柑桔绿霉病菌抑菌率达60%以上的有油茶籽、桃花心木、侧柏、海芋、山菅兰、水茄、深山含笑等的提取物.综合而言,油茶籽甲醇浸提物对柑桔青霉病菌、柑桔绿霉病菌和柑桔酸腐病菌的抑菌活性高于其他植物的甲醇浸提物.     

扩展青霉基因组DNA五种提取方法比较

为寻找一种适合于扩展青霉基因组DNA的提取方法,比较了固体培养、液体静置培养和液体振荡培养3种培养方式的提取效果,分别采用氯化苄法、蜗牛酶法、CTAB法、SDS法及异硫氰酸胍法提取扩展青霉菌基因组DNA,经DNA质量浓度测定及电泳分析,比较5种方法的差异,并利用扩展青霉的多聚半乳糖醛酸酶(Polygalacturonase)基因内一段保守序列,设计PCR引物,扩增大小为288 bp的特异目的基因,检测其灵敏性.结果表明:固体培养的方式较适合扩展青霉基因组DNA的提取,另外5种提取方法均能提取出扩展青霉菌基因组DNA,扩增出目的条带,其中氯化苄法和蜗牛酶法所提DNA的纯度均较好,但蜗牛酶法所提DNA量较少.因此,氯化苄法是5种提取方法中最可靠的DNA提取方法,所提DNA浓度高、纯度好、结果稳定,可作为PCR反应的模板进行特异性扩增,且该方法的最低检测限大约为1.01×10-1μg/mL.     

Survival of Penicillium bilaiae inoculated on canola seed treated with Vitavax RS and Extender

The fungicide Vitavax RS and the seed polymer Extender were sequentially applied to canola seed to determine their effect on the fungal inoculum, Penicillium bilaiae. In the laboratory, the fungicide was applied at the recommended rate of 23.4 ml kg^–1, and the polymer was applied by the manufacturer. Significant death of P. bilaiae occurred after 2.5 days on the Vitavax RS-treated seed and after 1.5 days with the seed treated with both Vitavax RS and Extender. In field treatments, the seed was sown at six sites in the fall just prior to freeze-up. Results from the laboratory experiment indicate that there should be no harmful effects of the Vitavax RS and Extender on the P. bilaiae at the time of seeding because the seeds were sown within 2 h of inoculation. The environmental extremes in 2001 and 2002 resulted in large variations in the data. P. bilaiae did not increase yield under these conditions.     

Eremophilane-Type Sesquiterpenes from a Marine-Derived Fungus Penicillium Copticola with Antitumor and Neuroprotective Activities

Chemical examination of a marine sponge-associated Penicillium copticola fungus resulted in the isolation of ten undescribed eremophilanes, namely copteremophilanes A–J (1–10), along with two new glycosides, 5-glycopenostatin F (11) and 5-glucopenostatin I (12). Their structures were determined by extensive spectroscopic data, in association with ECD data and chemical conversions for configurational assignments. Analogs 1, 2, and 10 represent a group of uncommon skeletons of eremophilanes with an aromatic ring and a methyl migration from C-5 to C-9, and analogs 11 and 12 are characteristic of a PKS scaffold bearing a glucose unit. The incorporation of a chlorinated phenylacetic unit in 3–9 is rarely found in nature. Analog 7 showed neuroprotective effect, whereas 8 exhibited selective inhibition against human non-small cell lung cancer cells (A549). This study enriched the chemical diversity of eremophilanes and extended their bioactivities to neuroprotection.     

Paspalines C–D and Paxillines B–D: New Indole Diterpenoids from Penicillium brefeldianum WZW-F-69

Five new indole diterpenoids named paspaline C–D (1–2) and paxilline B–D (3–5), as well as eleven known analogues (6–16), were identified from fungus Penicillium brefeldianum strain WZW-F-69, which was isolated from an abalone aquaculture base in Fujian province, China. Their structures were elucidated mainly through 1D- and 2D-NMR spectra analysis and ECD comparison. Compound 1 has a 6/5/5/6/6/8 hexacyclic ring system bearing 2,2-dimethyl-1,3-dioxocane, which is rare in natural products. Compound 2 has an unusual open F-ring structure. The cytotoxic activities against 10 cancer cell lines and antimicrobial activities against model bacteria and fungi of all compounds were assayed. No compound showed antimicrobial activity, but at a concentration of 1 μM, compounds 1 and 6 exhibited the highest inhibition rates of 71.2% and 83.4% against JeKo-1 cells and U2OS cells, respectively.     

耐辐射丝状真菌F161的分离鉴定及其对锶的吸附特性

[目的]鉴定分离自新疆某辐射污染区的丝状真菌F161,研究其吸附锶特性.[方法]采用形态学观察、分子生物学鉴定及碳源利用实验鉴定菌种;采用压力试验和吸附试验研究特性,对锶的吸附测定采用ICP-MS,对放射性90锶的吸附的测定采用液闪检测仪.[结果]菌株F161鉴定为青霉属真菌;菌株F161能够耐受10 KGy剂量的钴源...     

浙江省柑橘绿霉病菌对嘧菌酯的敏感性研究

采用孢子萌发法和生长速率法测定了2000~2006年间采自浙江衢州、杭州、金华、丽水的65个柑橘绿霉病病菌Penicillium digitatum菌株对嘧菌酯的敏感性。结果表明:嘧菌酯对供试菌株 孢子萌发和菌丝生长的EC50值均呈单峰分布,分别介于0.020 1 ~0.260 0 μg/mL和0.005 3 ~0.079 4 μg/mL 之间,平均值分别为0.042 6 μg/mL 和0.025 0 μg/mL。敏感性频次分析结果表明,该65个菌株孢子萌发和菌丝生长对嘧菌酯的敏感性频率分布均符合正态分布,其EC50平均值0.042 6±0.030 4 μg/mL 和0.025 0±0.012 9 μg/mL可分别作为柑橘绿霉病菌孢子萌发和菌丝生长对嘧菌酯的敏感基线。