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.     

Anti-Inflammatory Activity of Tanzawaic Acid Derivatives from a Marine-Derived Fungus Penicillium steckii 108YD142

Chemical investigation of a marine-derived fungus, Penicillium steckii 108YD142, resulted in the discovery of a new tanzawaic acid derivative, tanzawaic acid Q (1), together with four known analogues, tanzawaic acids A (2), C (3), D (4), and K (5). The structures of tanzawaic acid derivatives 1–5 were determined by the detailed analysis of 1D, 2D NMR and LC-MS data, along with chemical methods and literature data analysis. These compounds significantly inhibited nitric oxide (NO) production and the new tanzawaic acid Q (1) inhibited the lipopolysaccharide (LPS)-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins and mRNA expressions in RAW 264.7 macrophages. Additionally, compound 1 reduced the mRNA levels of inflammatory cytokines. Taken together, the results of this study demonstrated that the new tanzawaic acid derivative inhibits LPS-induced inflammation. This is the first report on the anti-inflammatory activity of tanzawaic acid Q (1).     

桔青霉CR-2内切葡聚糖酶蛋白纯化研究初探

以高效纤维素分解菌桔青霉(Penicillium citrinum)CR-2菌株为材料,利用分子筛及离子交换技术纯化分离其内切葡聚糖酶蛋白,首次获得了电泳纯的桔青霉内切葡聚糖酶蛋白组分,大小为27.26 kDa,最适作用温度为60℃,最适作用pH为5。对研究桔青霉纤维素酶降解纤维素的作用机理以及该菌株的改造应用具有重要意义。     

柠檬醛对绳状青霉抑制作用研究

为了弄清理化因素及作用方式对霉菌的影响,采用滤纸片法与挥发性物质活性检测法,研究不同浓度柠檬醛对绳状青霉(Penicillium funiculosum)的抑制作用,并检测不同处理时间对孢子萌发率的影响。结果表明,柠檬醛采用滤纸片法与挥发性活性物质检测法对P.funiculosum的最小抑制浓度(MIC)分别为6.0与3.0 mg.mL-1。在3.0 mg.mL-1浓度下处理10 min孢子萌发受到明显抑制,萌发时间比对照推迟6 h,萌发率降低21.7%;而处理120 min萌发时间比对照延迟10 h,萌发率降低83.8%。柠檬醛可通过熏蒸的方式对P.funiculosum起到较好的抑制作用。这为工农业产品防治霉菌的危害提供了新的理论依据。     

Evaluation of fungal epiphytes isolated from banana fruit surfaces for biocontrol of banana crown rot disease

Fungi isolated from the surface of banana fruits were evaluated for in vitro antagonism towards Lasiodiplodia theobromae. Thirteen fungi exhibiting pronounced growth inhibition of test pathogens were further tested for antibiosis against Thielaviopsis paradoxa, Colletotrichum musae, and Fusarium verticillioides. Clonostachys byssicola, Curvularia pallescens, Penicillium oxalicum, and Trichoderma harzianum were antagonistic to all test pathogens. Inhibition by C. pallescens and P. oxalicum to pathogens was at a distance, while C. byssicola and T. harzianum directly parasitized and killed the pathogens. The metabolites of C. byssicola, C. pallescens, and T. harzianum significantly affected the mycelial growth and conidial germination of the pathogens. In the artificial inoculation study, the antagonists survived and colonized banana fruits after 3 d. Interfungal parasitic relationship was observed between the antagonist and pathogen on artificial media and natural substrate. Postharvest application in the packing house showed that the incidence of crown rot in antagonist-treated banana was significantly lower when compared to fungicide and untreated control fruits.