草酸青霉菌I1的cDNA文库构建及其溶磷相关基因的筛选

【目的】构建草酸青霉菌I1的cDNA文库,筛选溶磷相关基因。【方法】利用SMART技术构建草酸青霉菌I1的初级cDNA文库,通过难溶磷培养基筛选具有溶磷能力的转化子,测序并进行生物信息学分析。在难溶磷液体培养基中,进行转化子对溶液pH值、可溶磷含量的影响和产有机酸试验。【结果】成功构建了草酸青霉菌I1的初级cDNA文库,其库容量约为5.29×106 cfu•mL-1,重组率为99%;利用难溶磷固体培养基筛选,得到具有溶磷圈的转化子48个,其中转化子I-4的cDNA序列全长536 bp,为一个新的序列,基因编码氨基酸残基序列长129 n.t。转化子E. coli HST08 I-4在液体难溶磷培养基中培养,提高了有机酸的表达量,并增加了有机酸的种类,在培养12 h后,开始产生乙酸,24 h后,溶液中产生乳酸、苹果酸和α-酮戊二酸,培养36 h,溶液pH值由6.32降到3.69,可溶磷含量达到0.1076 mg•mL-1。【结论】从草酸青霉I1中筛选到一个溶磷相关基因pstI。     

微重力对扩展青霉孢子萌发、菌丝生长和致病力的影响

 After being onto 22nd recoverable satellite of China for 18-day spaceflight under microgravity condition,me growth and pathogenicity of PeniciUium expansum were investigated.Spore germination rate of the spaceflight pathogen was insignificantly lower than that of the ground control.After germination,germ tube elongation of spaceflight pathogen was slower,as well as mycelia growth.However,there was no significant difference according to independent-samples T-test.The consistent results were obtained in vivo.The space. flight pathogen exhibited a little weaker pathogenicity in peach fruit.These findings suggested that the microgravity reduced the growth and pathogenicity of P.expansum.but the effect Was not marked.     

新型含氮化合物对柑桔绿霉菌的离体抑菌活性及其构效关系

为寻找对柑桔绿霉菌具有抑制作用的活性化合物,采用生长速率法并结合光谱法评价两种商品化三唑类杀真菌剂和四种新型含氮化合物对柑桔绿霉菌的抑菌活性及与柑桔绿霉菌CYP51的结合能力。结果表明:7-甲氧基-2-氢-苯并[b][1,4]噻嗪-3-胺对柑桔绿霉菌表现出强抑制作用,EC50值达1.18mg/L,与商品化三唑类杀真菌剂烯唑醇的EC50值(0.09mg/L)接近;而其余三种新型含氮化合物显示出中等程度的抑制作用,EC50值分别为7.88、10.09和38.56mg/L。不同化合物与异源表达的重组柑桔绿霉菌CYP51的结合能力不同,对柑桔绿霉菌生长抑制的EC50越大,结合常数越大,即化合物与靶标酶CYP51的结合能力与抑菌活性呈正相关。     

植物乳杆菌IMAU10116产生抗娄地青霉活性物质培养基的优化

[目的]筛选对娄地青霉有较强抑菌活性的植物乳杆菌并提高其抗真菌活性。[方法]将活化后的植物乳杆菌IMAU10116接种到MRS液体培养基中培养,采用双层平板点接法评价其抗娄地青霉菌的活性。[结果]单因素试验表明,以葡萄糖为碳源时,植物乳杆菌IMAU10116对娄地青霉的抑制效果最好;植物乳杆菌以麦芽浸粉为氮源时,抑菌效果最好;抗真菌乳酸菌产生抗菌物质的最佳生长因子为玉米浆粉。植物乳杆菌IMAU10116最佳培养基组成为:葡萄糖20g/L+麦芽浸粉20g/L+玉米浆粉7g/L+适量无机盐。用优化培养基培养的植物乳杆菌IMAU10116抑制娄地青霉菌产生的抑菌圈为18.6mm,用MRS培养基所产生的抑菌圈为15.0mm。[结论]植物乳杆菌IMAU10116对娄地青霉有很好的抑制作用,有望在食品及饲料添加剂领域获得较好的应用。     

凤仙透骨草中抑菌活性物质提取工艺研究

以意大利青霉做指示菌,以抑菌圈直径为活性追踪指标,在单因素实验的基础上通过二次回归正交旋转组合设计进行凤仙透骨草中抑菌活性物质的提取工艺参数优化。结果表明:最佳提取工艺条件为φ(乙醇)=96.8%,溶剂倍数10倍,提取温度50℃,提取时间3 h,在此优化条件下抑菌圈直径为36.95 mm。各因素对凤仙透骨草提取物抑菌效果的影响由大到小依次为:乙醇浓度,溶剂倍数,提取时间,提取温度。     

马克斯克鲁维酵母对柑橘采后绿霉病的抑制效果

通过活体(in vivo)和离体(in vitro)试验,研究拮抗酵母菌株Kluyverom yces marxianus与不同浓度钼酸铵混合使用对柑橘采后绿霉病(Penicillium digitatum)的防治效果,以及钼酸铵对K.marxianus菌株生长和繁殖的影响.结果表明:不同浓度的钼酸铵对K.marxia...     

纤维素酶/木聚糖酶产生菌株的筛选及其降解小麦秸秆的研究

从自然环境中筛选出1株可同时分泌纤维素酶和木聚糖酶的菌株,并对其降解小麦(Triticum aestivum L.)秸秆的特性进行分析。结果表明,ZH-19菌株可同时高产纤维素酶和木聚糖酶。经形态特征和ITS保守区测序分析确定该菌株为Penicillium thiersii。菌株降解小麦秸秆的过程中,纤维素酶活和木聚糖酶酶活分别在第6天和第7.5天达到其最大值,分别为145.54、93.20 U/m L;纤维素比半纤维素降解的速率要快,表明在小麦秸杆降解过程中,可能需要纤维素酶、半纤维素酶的协同作用,才能实现对木质纤维素的最大降解。     

Control of postharvest diseases on citrus fruit by preharvest application of the biocontrol agent Pantoea agglomerans CPA-2: Part I. Study of different formulation strategies to improve survival of cells in unfavourable environmental conditions

The objective in the present study was to investigate the survival and effectiveness of different biological agent Pantoea agglomerans formulations against Penicillium spp. with different preharvest treatments. Results indicated a high sensitivity of non-adapted and osmotic-adapted P. agglomerans cells to environmental conditions in the field, resulting in preharvest treatments which were ineffective against Penicillium spp. In the second part of this study, dry conditions and solar radiation were identified as important environmental conditions that seriously affect populations of P. agglomerans cells. Different formulation strategies were tested in order to improve the resistance of cells to unfavourable environmental conditions. Osmotic-adapted P. agglomerans cells in the presence of 25 g L⁻¹ of NaCl in the production medium [osmotic-adapted treatment (P25)] or at water activities (a_w) of 0.98 [osmotic-adapted treatment (P98)] had higher survival rates than non-adapted cells, when these cells were sprayed on oranges and stored in hermetically sealed chambers at a low RH of 43%. Among seven additives tested, the presence of 5% Fungicover in the bacterial suspension improved adherence and persistence of P. agglomerans cells on oranges exposed to unfavourable conditions. Therefore, while P. agglomerans cells sprayed alone had log values of 0.5 CFU cm⁻², in combination with Fungicover the population level of P. agglomerans cells reached log values of 5 and 4.2 CFU cm⁻², at 0 and 24 h after application. Lyophilised cells showed greater resistance to unfavourable environmental conditions than fresh cells. The present study has demonstrated that the formulation improvement can provide better performance of biocontrol agents under environmental conditions non-conducive for growth and survival.     

Verrucisidinol and verrucosidinol acetate, two pyrone-type polyketides isolated from a marine derived fungus, Penicillium aurantiogriseum

The new secondary metabolites verrucosidinol (1) and its derivative verrucosidinol acetate (2), together with a potent neurotoxin verrucosidin (3), a congener norverrucosidin (4) and a mixture of two known phytotoxic metabolites terrestric acids (5 and 6), were isolated from the marine derived fungus Penicillium aurantiogriseum. Verrucosidinol has a ring-opened ethylene oxide moiety in the polyene α-pyrone skeleton, and verrucosidinol acetate is its acetate derivative. The chemical structures were determined by comparing with literature data and a combination of spectroscopic techniques, including high resolution mass spectrum and two-dimentional nuclear magnetic resonance spectroscopic analysis.     

Dihydroisocoumarins from the Mangrove-Derived Fungus Penicillium citrinum

Three new dihydroisocoumarin penicimarins G–I (1–3), together with one known dihydroisocoumarin (4) and three known meroterpenoids (5–7), were obtained from a fungus Penicillium citrinum isolated from the mangrove Bruguiera sexangula var. rhynchopetala collected in the South China Sea. Their structures were elucidated by the detailed analysis of spectroscopic data. The absolute configuration of 1 was determined by the X-ray diffraction analysis using Cu Kα radiation. The absolute configurations of 2 and 3 were determined by comparison of their circular dichroism (CD) spectra with the literature. All compounds were evaluated for their antibacterial activities and cytotoxic activities.