真菌联合稀碱预处理杜仲叶提取杜仲胶的工艺研究

以杜仲干叶为原料,经稀碱和绿色木霉联合处理以除去杜仲表面覆盖的角质层,同时洗脱一些可溶性杂质,并且破坏杜仲叶的细胞壁与纤维结构,再以石油醚作为提取溶剂,得到粗胶再经丙酮浸洗获得杜仲精胶。用0.45%NaOH在75℃下除去杜仲叶表面的角质层,并且同时脱除一些可溶性活性成分(如:多糖、黄酮类、京尼平苷等),之后得杜仲叶干燥,利用绿色木霉去破坏杜仲叶的细胞壁与纤维结构,在85℃条件下以石油醚作为提取溶剂提取杜仲胶。最后,经测得未处理前杜仲叶中的杜仲胶的含量为1.78%,0.45%NaOH稀碱预处理后含量为3.16%,绿色木霉发酵后含量为4.36%。预处理前,有机溶剂一次提取率为0.73%,纯度为83.7%。稀碱与真菌联合预处理后一次提取率为2.85%,纯度为96.6%。本工艺以稀碱与绿色木霉共同作用,减少了有机溶剂的用量,与传统工艺相比,更加的绿色环保,安全有效,为杜仲胶的提取提供了科学有效的依据。     

Trichoderma spp. Antagonism to the Dermatophyte Trichophyton rubrum: Implications in Treatment of Onychomycosis

Onychomycosis--the dermatophytic invasion of the nail--is difficult to eradicate with drug treatment. The hyphae of the main invading pathogen, Trichophyton rubrum, are often interwoven with the nail plate, preventing effective anti-mycotic agents from reaching its growing tips. An alternative approach to treat onychomycosis may possibly be the application of a biological control agent against the pathogen. In analogy with the success of biocontrol of phytopathogenic fungi, we screened a series of commercially available Trichoderma strains for potential antagonism between Trichoderma and Trichophyton spp. A wide spectrum of antagonism capacity, ranging from effective overgrowth to no interaction was found, with Trichoderma virens NRRL 26672 being the most effective against the Trichophyton strains tested e.g. T. rubrum NCPF118. Furthermore, T. virens NRRL 26672 grown with T. rubrum NCPF118 hyphae as a carbon source, exhibited enhanced induced secretion of active extracellular chitinases and beta-glucosidases, affecting lysis and sporulation on T. rubrum NCPF118 hyphae. Growth of Trichod. virens NRRL 26672 in poor medium also resulted in secretion of antibiotics active in arresting the growth of T. rubrum NCPF118 inoculum. Our findings may open new directions for the treatment of onychomycosis, either in combination with known medications or as a new "natural" route.     

木霉诱导下山新杨PodaPIN9基因的组织表达调控

PIN蛋白具有多个跨膜结构域,影响着高等植物生长素的外向运输和众多生长发育过程。木霉菌是能促进植物生长、提高其对多种病害防御作用的生防因子。研究木霉菌对木本植物山新杨生长素的极性分布的影响有重要意义。克隆了山新杨PodaPIN9基因,对其核酸和蛋白序列进行分析;同时,构建的进化树显示PodaPIN9与6个物种的9条PIN基因具有高度一致性（>80%）。qRT-PCR分析表明,PodaPIN9在山新杨茎尖、成熟叶和根中均有表达。在根中表达量极低;在茎尖和叶中的表达量极高,分别是根中的503和346倍。该基因受木霉影响在茎尖和叶中的表达量均显著下调;而根中的表达量显著上调,达到对照的32.01倍。并发现根际接种木霉48 h会使杨树茎尖、叶和根中生长素含量降低。说明木霉菌能影响杨树茎尖、叶和根中IAA水平及PodaPIN9的表达量。并且Pearson相关性分析表明在茎尖、叶和根中,PodaPIN9表达量与IAA水平具有不同的相关性。     

纤维素酶的固态发酵及酶学性质的研究

对绿色木霉产纤维素酶的固态发酵条件进行研究,显示其最优产酶条件为:稻草:麸皮=3:2,水分250%,最佳氮源为0.5%(NH4)2SO4,最佳培养时间3天,温度30℃,接种量10%,初始pH6.0～7.0,在此条件下,每克干曲酶活分别高达18.4FPAU/g,56.7CMCU/g。同时对酶解作用条件进行了初步研究,发现pH5.2时对滤纸酶活力最高,pH4.8时对脱脂棉活力最高。降解温度以滤纸55℃,脱脂棉50℃为最佳。实验还发现乙醇对酶的降解有抑制作用。