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【背景】出芽短梗霉(Aureobasidium pullulans)是在生活史中有酵母状细胞生长阶段,并合成黑色素的一种黑酵母(Black yeast),具有典型的细胞多形性,可分化形成酵母状细胞(Yeast-like cell,YL)、膨大细胞(Swollen cell,SC)、厚垣孢子(Chlamydospore,CH)、菌丝(Hyphae,HY)、念珠状菌丝(Monilioid hyphae,MH)、有隔膜膨大细胞(Septate swollen cell,SSC)、分生组织状结构(Meristematic structure,MS),其中膨大细胞既可以作为生长的细胞类型,也可分化为其他的细胞类型。出芽短梗霉的形态分化是可调控的,调控因子有pH、温度、营养条件等。【目的】探究不同的氧气浓度、温度、盐浓度、营养水平对出芽短梗霉细胞形态的影响。【方法】利用显微镜、美兰染色等技术观察不同条件对出芽短梗霉细胞形态的影响。【结果】在完全无氧的试管底部菌体不能生长;在高层半固体表层(高氧气浓度),酵母状细胞(YL)在营养丰富的生长初期出芽繁殖,在养分匮乏的培养后期诱导酵母状细胞(YL)经过膨大细胞(SC)形成厚垣孢子(CH)并合成黑色素;在营养丰富的生长初期,半固体试管浅表层和中间层(微好氧)低浓度氧气诱导YL经过SC形成HY侵入性生长。养分差异对菌体细胞多形性分化影响显著,环境适宜养分丰富(Yeast extract peptone dextrose medium,YPD),以YL生长,不需要分化成HY;环境适宜养分不丰富(Potato dextrose agar,PDA),分化成SC或HY以适应或逃离环境;环境不适宜养分匮乏时(Malt extract agar,MEA),SC或HY分化成CH或MH进入休眠阶段。10%NaCl胁迫降低菌体生长速度,抑制色素合成、HY和MH的形成,并且细胞主要以YL生长繁殖。在相同质量浓度(10%)的KCl或Na2SO4渗透胁迫条件下,细胞多形性表型均为YL发达,HY及MH被抑制,说明高渗胁迫阻止了酵母状细胞向菌丝和厚垣孢子的分化。温度实验中,SC比YL耐高温,MS比SC耐高温。【结论】营养状态对出芽短梗霉细胞分化影响最大。 相似文献
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在摇瓶发酵条件研究的基础上。于16L自控发酵罐上进行了罐上发酵条件优化研究。发现以10%淀粉水解物为碳源时,淀粉水解物的最适DE值为40-50,发酵培养基中的硫酸铵最适用量不同于摇瓶发酵时的量,种龄和接种量、通气量、罐压、搅拌速度和搅拌叶轮挡数等均对多糖的产生有较大的影响。另外还进行了发酵过程的动力学的研究。 相似文献
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对一株野生型的出芽短梗霉(Aureobasidiumpullulans)Ftl和从Ftl出发经原生质体再生筛选出的菌株R45进行了摇瓶发酵产普罗蓝糖的比较研究,结果表明R45无论从形态,菌体生长情况,还是从普罗蓝糖的产量,黑色素的产生等方面都与亲株Ftl有明显的区别,说明R45是一株具有一定生产价值的变异菌株。 相似文献
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探讨了丛生丝孢酵母菌的生物学鉴定特性。采用真菌培养法观察丛生丝孢酵母菌的培养特性、同化试验;耐受试验测定对放线菌酮的耐受性;体外双相形态转换试验确定霉菌相及酵母相;微量稀释法进行抗真菌药物敏感试验;温度耐受性试验、干燥试验、紫外线照射试验测定其抵抗力;小鼠腹腔接种法观察其侵袭力。本菌为双相型真菌,经分离培养该菌呈现真菌所特有的菌落特征,在沙氏肉汤中呈菌膜和沉淀生长;玉米粉琼脂小培养,在镜下可见到大小不等圆形和卵圆形孢子。对10种糖类同化试验阳性,不分解尿素,还原硝酸盐。对氟康唑等4种抗真菌药均敏感;对温度、干燥、紫外线有一定耐受力;侵袭力较弱,组织内酵母相呈细胞内感染。结论观察丛生丝孢酵母菌的生物学鉴定特性,对丛生丝孢酵母菌的实验室鉴定奠定基础和临床诊断提供依据。 相似文献
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Abstract Production of pullulan by five strains of Aureobasidium pullulans was compared in three media with three carbohydrate sources. Our goal was to screen strains and media to obtain pullulan in maximal yield, purity, and stability. Pullulan yields and properties were strongly affected by strain specificity, but a single medium performed best with most strains. Sucrose was the preferred carbohydrate for all five strains. A "color variant" strain of Aureobasidium , NRRL Y-12974, possibly representing a distinct species, produced a polysaccharide of intermediate molecular weight which was stable during storage at 4°C, heating to 100°C, and high shearing action. This polysaccharide was 70% pullulanase sensitive and contained the least contaminating melanin pigment. 相似文献
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K. Takizawa K. Fukushima Y. Maebayashi K. Okada K. Nishimura M. Miyaji 《FEMS microbiology letters》1992,92(2):120-132
Abstract A naturally occurring member of ubiquinone (Q) group, a dihydroubiquinone-9 (Q-9 (H2 )), has been isolated as a minor ubiquinone component from the fungus Aureobasidium pullulans . By ultraviolet absorption, mass and nuclear magnetic resonance spectrometric studies, the structure of Q-9 (H2 ) was found to be 2,3-dimethoxy-5-methyl-6-IX-dihydromultiprenyl9 -1,4-benzoquinone (I). 相似文献
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Protoplasts prepared from yeast-like cells, hyphae and chlamydospores of Aureobasidium pullulans can take up heavy metals such as Zn2+, Co2+, Cd2+ and Cu2+. In relation to intact cells, the sensitivity of protoplasts to Cu2+ and Cd2+ was increased although chlamydospore protoplasts were more tolerant than yeast-like cell protoplasts. Surface binding of metals was reduced in protoplasts as compared with intact cells and this reduction was particularly evident for chlamydospore protoplasts. At the highest concentrations used, uptake of Zn2+, Co2+ and Cd2+ by yeast-like cell protoplasts was greater than that observed in intact cells which may have been due to toxicity, especially for Cd2+, resulting in increased membrane permeability, though for Zn2+ and Co2+ some barrier effect of the cell wall could not be completely discounted. Chlamydospore protoplasts were capable of intracellular metal uptake, unlike intact chlamydospores, and for Zn2+, uptake appeared to be via a different system less specific than that of the other cell types. For chlamydospores, the use of protoplasts confirmed the importance of the cell wall in preventing entry of metal ions into the cell. 相似文献