Effects of three esca-associated fungi on Vitis vinifera L.: IV. Diffusion through the xylem of metabolites produced by two tracheiphilous fungi in the woody tissue of grapevine leads to esca-like symptoms on leaves and berries

Two naphthalenone pentaketides (scytalone and isosclerone) and α-glucans (pullulan) are produced in vitro and in planta by Phaeomoniella chlamydospora (Pch) and Togninia minima (Tmi), two tracheiphilous fungi associated with the ‘esca’ disease of grapevines. The possible role of such fungal metabolites in inducing symptoms on leaves and berries was studied in a vineyard of Vitis vinifera cv. Italia located in southern Italy. During early spring, pruning off two to four branches per vine allowed samples of xylem sap to be collected. Vine bleeding, assessed as ml day⁻¹ vine⁻¹, reached its maximum at bud burst and stopped within 28 days. The total amount of sap collected from healthy vines was about a quarter of that from esca-affected vines. During the same period, the leaf water potential of diseased vines increased progressively (i.e. showed less negative values), indicating a dysfunction in water and nutrient supply to the new growth. Both fungi were isolated from the xylem sap and from the woody tissue of branches and the trunk of diseased vines. Conidia isolated from the sap showed a high germination rate (>90%). Bioactive concentrations of the two pentaketides were detected in xylem sap, leaves and berries at various stages of seasonal growth. Exopolysaccharides, including pullulan, were found in the xylem sap. Absorption of culture filtrates of Pch and Tmi, as well as weak solutions of purified preparations of scytalone, isosclerone or pullulan, on detached leaves and berries caused symptoms similar to those shown by the esca-affected vines in the field.     

紫外诱变选育普鲁兰多糖高产菌株

[目的]选育普鲁兰多糖的高产菌株。[方法]以Aureobasidium pullulan NNG为出发菌株,采用紫外诱变的方法,筛选普鲁兰多糖高产菌株。[结果]出发菌株A.pullulan NNG摇瓶发酵所得普鲁兰多糖产量为28.79 g/L,而突变菌株UV-1产糖量为46.96 g/L,是出发菌株的1.69倍。通过突变株UV-1与出发菌株NNG发酵期内形态的观察,发现在发酵的第7天突变株UV-1膨胀细胞数达到最高。[结论]该研究可以为普鲁兰多糖高产菌株的筛选提供理论依据。     

生物絮凝剂(普鲁兰)处理印染废水的研究

[目的]确定生物絮凝剂普鲁兰处理印染废水的最佳絮凝条件,开发有效地处理印染废水的新技术。[方法]用新型微生物絮凝剂普鲁兰作为生物絮凝剂,AlCl3溶液作为助凝剂,对印染废水分别进行条件试验和混凝正交试验,寻找最佳絮凝范围和条件,并对不同的普鲁兰用量、助凝剂用量、pH值等6个因素进行了探讨。[结果]条件试验表明,普鲁兰与AlCl3的最佳配比为2∶6。CODcr去除率正交分析表明,6个因素对CODcr去除率的影响依次为:混合时间>普鲁兰用量>反应时间>AlCl3>沉淀时间>pH值。最佳絮凝条件为:3g/L普鲁兰、12 g/L AlCl3溶液、pH值6.5、混合时间30 s、反应时间15 min和沉淀时间40 min。[结论]在最佳絮凝条件下,印染废水中CODcr去除率达81%。     

短梗霉多糖·丙烯酰胺接枝共聚物对模拟偶氮染料废水脱色性能研究

以短梗霉多糖和丙烯酰胺为原料制备了接枝共聚物Glc-cAM,并将Glc-cAM用于甲基红和酸性橙2种模拟染料废水的脱色处理,讨论了溶液初始pH值、染料初始浓度、聚合物Glc-cAM投加量和接枝率等因素对脱色率的影响.结果表明:Glc-cAM对偶氮染料废水具有良好脱色效果.最佳脱色条件为:初始pH值为3,染料浓度为100mg/L,聚合物投放剂量为6.0g/L,接枝率为60%.     

高压电晕电场对出芽短梗霉菌诱变的研究

[目的]通过研究高压电晕电场诱变对出芽短梗霉多糖产量的影响,筛选出高产优质的出芽短梗霉菌株。[方法]采用高压电晕电场对出芽短梗霉进行诱变,在临界放电电压下诱变不同时间,测定出芽短梗霉的性状和多糖产量的变化。[结果]在临界放电电压4.4 k V下的最佳诱变时间是60 min;经过2次连续诱变,多糖产量达到9.57 g/L,是原始菌株的3倍多,发酵液颜色为米白色,最终p H为4.2左右;连续传代培养10代,其生状和产量无明显变化,传代稳定。[结论]高压电晕电场对出芽短梗霉菌的普鲁兰产量提高有显著作用。     

不同微量元素对出芽短梗霉发酵的影响

以实验室保存的出芽短梗霉UV60为菌株,研究了CrCl3、ZnSO4、MnSO4和C5H11NO2Se在出芽短梗霉液体发酵过程中对短梗霉多糖产量及生物量的影响。经过单因素及正交试验获得了最优的微量元素组成,即0.5 mg/L CrCl3、0.15 g/L ZnSO4、0.2 mg/L MnSO4、15μg/L C5H11NO2Se。采用上述优化的微量元素浓度,多糖产量为28.9 g/L,较优化前多糖产量明显提高,为短梗霉多糖的发酵生产提供了参考依据。     

胞外多糖pullulan处理养猪场污水效果分析

用pullulan处理养猪场污水 ,结果表明 :污水的稀释倍数与pullulan的添加量对处理效果有极显著的影响。当Pullulan在 2倍稀释污水中的添加量达到 3mg/kg时 ,污水的生物需氧量 (BOD)、化学耗氧量 (COD)、总P、N的去除率达到 90 %以上 ;大肠杆菌的去除率达到 95 %以上 ,透过率也从 8%上升到 92 %。     

茁霉多糖生物合成及在食品工业中的应用

综述了茁霉多糖的分子结构、性质、生物合成,并且简要叙述了茁霉多糖在食品工业中的应用。