粘帚霉可湿性粉剂助剂的初步研究

可湿性粉剂是生物农药的重要剂型。通过平板培养法，测定菌落形成单位数（cfu值1，开展了可湿性粉剂多种常用助剂对高效生防真菌粉红粘帚霉67．1菌株孢子的生物学相容性研究。所试载体中，滑石粉等4种处理与对照没有显著性的差异，对粘帚霉孢子活力影响不明显；所试润湿分散剂中，木质素磺酸钙与对照没有显著性差异，对粘帚霉孢子活力影响不明显；所试紫外保护剂均对孢子活力无显著影响，但在紫外灯照射3min的条件下，只有腐植酸和糊精能有效保护孢子活力；常用稳定剂CMC—Na（羧甲基纤维素钠）对孢子活力无影响。上述多种与粘帚霉孢子具良好生物学相容性助剂的确定，为粘帚霉可湿性粉剂的研究提供重要依据。     

Bacillus pumilus HN-10抗菌肽P-1对粉红单端孢的抑菌机理

Bacillus pumilus HN-10抗菌肽P-1是一种对粉红单端孢（Trichothecium roseum）具有很强抑菌作用的肽,但其抑菌机理尚不明确。本研究从细胞膜通透性、蛋白合成和核酸合成3 方面研究其抑菌机理。通过大分子释放量和电导率研究抗菌肽P-1对粉红单端孢细胞膜通透性的影响;经胞内蛋白含量测定及胞内蛋白十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分析研究抗菌肽P-1对蛋白合成的影响;采用琼脂糖凝胶电泳和荧光光谱分析抗菌肽P-1对粉红单端孢DNA的凝胶阻滞作用及与溴化乙锭（ethidium bromide,EB）竞争性结合作用,并通过DNA和RNA相对含量来研究粉红单端孢核酸合成是否受到抑制。结果表明：抗菌肽P-1可引起粉红单端孢细胞膜通透性增加,胞内电解质和大分子物质外泄;同时,菌体蛋白合成受到抑制,尤其对分子质量在43.0～97.4 kDa之间的蛋白最为明显;抗菌肽P-1对DNA没有明显阻滞作用,但其能与EB竞争性结合DNA,使核酸合成受到抑制,导致菌体代谢紊乱,影响蛋白质的正常表达,进而起到抑菌作用。     

Trichothecium roseum的酸碱属性及pH值对其胞外酶活性和致病性的影响

目的：明确粉红单端孢（Trichothecium roseum）侵染果实的酸碱性质,测定3 种pH值孢子悬浮液接种对苹果果实病斑直径及胞外酶活性的影响。方法：用T. roseum接种“富士”苹果,测定果实病斑处的pH值变化。用pH值分别为3、5和7的孢子悬浮液接种果实,观察接种对果实病斑直径及病斑处果胶酶和纤维素酶活性的影响。结果：T. roseum接种后果实病斑处的pH值显著升高,由第0天的3.54升高至第12天的4.84,提高了36.7%。3 种pH值孢子悬浮液接种果实后,以pH 7接种的果实病斑直径最大,第9天时分别高出pH 5与pH 3接种的35.2%与68.0%。pH 7接种的果实病斑处具有最高的果胶酶及纤维素酶活性,第9天时的果胶甲酯酶、果胶甲基多聚半乳糖醛酸酶、多聚半乳糖醛酸酶活性分别为pH 3接种的2.95、1.61 倍和1.68 倍,为pH 5接种的2、1.25 倍和1.39 倍。此外,pH 7接种的果实病斑处纤维素酶和β-葡萄糖苷酶第9天的活性分别为pH 3接种的1.97 倍和1.64 倍,为pH 5接种的1.33 倍和1.3 倍。结论：T. roseum属碱化菌,中性或偏碱环境可提高该菌损伤接种苹果果实病斑处的胞外酶活性,增强其致病性。     

玉米赤霉烯酮毒素降解酶基因的克隆及在毕赤酵母中的高效表达

以粉红黏帚霉菌株总RNA为模板,采用RT-PCR技术克隆得到玉米赤霉烯酮降解酶基因cD-NA序列,插入pPIC9K载体后,转化毕赤酵母。经MD板筛选,得到His+型重组子,进行甲醇诱导表达,并进行了降解玉米赤霉烯酮能力测定。克隆得到的cDNA序列全长795 bp,连续编码编码264个氨基酸;阳性克隆子在甲醇诱导培养3~5 d后,HPLC检测证实,经表达后的酶液能完全降解液体中玉米赤霉烯酮(ZEN)。     

Trichothecium roseum蛋白激发子诱导杏果抗黑斑病的作用机理

研究非亲和菌株粉红单端孢（Trichothecium roseum）菌体蛋白激发子对杏果实抗黑斑病的诱导效果及其作用机理。以‘兰州大接杏’为试材,通过处理后不同时间损伤接种杏果黑斑病菌（Alternaria alternata）,研究T. roseum蛋白激发子对杏果实黑斑病抗病性的诱导及其时效性,同时进一步研究最佳处理质量浓度对杏果实组织活性氧及抗性相关酶的影响。结果表明,T. roseum蛋白激发子处理可显著抑制损伤接种杏果病斑的扩展（P＜0.05）,其中14.4 μg/mL蛋白激发子的控制效果最好,且诱导处理72 h时杏果产生最大抗性。T. roseum蛋白激发子处理后杏果组织O2－·的生成速率和H2O2含量分别在48 h和72 h出现明显的峰值,同时处理的果实组织超氧化物歧化酶、过氧化物酶、多酚氧化酶、β-1,3-葡聚糖酶和几丁质酶活性均有所增强。T. roseum菌体蛋白激发子处理能显著增强杏果组织的抗性,其可能是通过激发活性氧爆发和提高杏果实抗病性相关酶的活性来实现的。可见T. roseum蛋白激发子可以作为一种有潜力的诱抗剂应用于采后病害的控制。     

微生物发酵生产二十二碳六烯酸的研究

DHA作为多不饱和脂肪酸系列中重要的一种,现已发现其对人类的许多疾病的治疗和预防有着重要的意义。目前它的分离纯化主要来自海洋鱼油,存在着许多不利因素限制其生产及应用,研究表明微生物具有大规模工业化生产DHA的能力。本文通过对破囊壶菌ATCC34304等四株菌的发酵液的分析,发现ATCC34304易于培养且DHA含量高,对ATCC34304的发酵培养基组分和发酵条件进行进一步研究后得出,在以淀粉为碳源的培养基中,28℃170rpm摇床光照培养6天,DHA含量达320.1mg/L。     

粉红单端孢病害对厚皮甜瓜贮藏期挥发性物质的影响

本文通过果腔顶空法结合色谱及色-质联用仪分析监测“银帝”厚皮甜瓜挥发性物质在常温贮藏条件下的变化,研究粉红单端孢病害侵染对其挥发性物质释放量的影响。结果表明,粉红单端孢Trichotheciumroseum侵染会促使甜瓜的挥发性物质提前释放,但不同挥发性物质成分的变化趋势不同。     

超声波破碎Thraustochytrium提取脂质的研究

本文研究了超声波破碎破囊壶菌细胞及其脂质提取的方法,并对脂质脂肪酸组成进行了分析.实验结果表明,超声波能有效破碎破囊壶菌细胞,从而可使脂质得率提高60%;脂质脂肪酸组成以DHA为主,含量高达60%以上,其它脂肪酸含量均不到10%.     

Effect of salt concentration on production of polyunsaturated fatty acids in <Emphasis Type="Italic">Thraustochytrium aureum</Emphasis> ATCC 34304

This study attempted to characterize the effects of NaCl and MgSO₄ as the primary components of sea salt affecting the yields of production of polyunsaturated fatty acids (PUFAs) by Thraustochytrium aureum ATCC 34304. Reductions in the NaCl concentration of the culture medium suppressed the formation of palmitic acid (PA, C16: 0) but enhanced the production of PUFAs, which induced an increase of the concentration of docosahexaenoic acid (DHA, C22: 6) up to 46.65% from 44.26%. MgSO₄ revealed a similar, yet more highly significant, effect on the fatty acids profile than NaCl. The yields of PUFAs and DHA showed maximum values such as 67.10% and 49.47%, respectively, at the concentration of 10 g L⁻¹ for NaCl and 0 g L⁻¹ for MgSO₄. However, the quantities of mono-and diunsaturated fatty acids, oleic acid (OA, C18: 1) and linoleic acid (LA, C18: 2) at the same concentrations, were compared with those of normal culture medium. Additionally, it was investigated that the increase of culture temperature reduced PUFAs contents but the reductions were recovered by the removal of MgSO₄ form the culture medium, which showed that concentration of salts and culture temperature affected independently the production of PUFAs in T. aureum.     

Use of silicon oxide and sodium silicate for controlling Trichothecium roseum postharvest rot in Chinese cantaloupe (Cucumis melo L.)

Silicon oxide and sodium silicate were investigated as potential agents for the control of postharvest pink rot in Chinese cantaloupe (cultivar Yujingxing) caused by Trichothecium roseum. In vitro tests showed that sodium silicate, when added to potato dextrose agar, was effective in suppressing the radial growth of the pathogen on the medium, whereas silicon oxide was ineffective. The effectiveness of sodium silicate increased with concentration, and the growth of the fungus was completely inhibited at 100 mm . When melons were dipped in the solutions, both silicon oxide and sodium silicate significantly (P < 0.01) reduced the severity of pink rot of the cantaloupe with lesion diameters reduced by up to fivefold when compared with the controls. Scanning electron microscopy‐energy dispersive X‐ray analysis showed that silicon (Si)‐treated melons had a smoother surface feature and higher Si levels in the epidermis, especially at the stomata and along the junction between the exocarp and mesocarp. Enhanced peroxidase and phenylalanine ammonia lyase activities were observed in sodium‐silicate‐treated melons but not in those treated with silicon oxide. The results indicate that different mechanisms might be involved in sodium silicate and silicon‐oxide‐initiated reduction of postharvest pink rot in Chinese cantaloupe.