低聚果糖转移酶的分离纯化及性质研究

米曲霉发酵液经硫酸铵分级沉淀、ＤＥＡＥ－ｃｅｌｌｕｌｏｓｅ ＤＥ－５２吸附洗脱等步骤,得到了聚丙烯酰胺凝胶电泳均一的低聚果糖转移酶。得率４．４％,比活力为３５１５ｕ／ｍｇ,纯化了１５５５倍。分子量为７．８９＊１０＾４。低聚果糖转移酶最适ＰＨ为６．３,最适温度６０℃,热稳定性较好,对底物蔗糖的Ｋｍ值的０．６５ｍｏｌ／Ｌ。     

褐藻果叶马尾藻化学成分的研究

采用稻瘟霉模型生物活性追踪方法，应用多种层析手段，从采自广西北海的褐藻果叶马尾藻（Sar-gassum carpophyllum）中分离得到8个化合物，应用多种波谱技术，分别确定为：戈米辛N（Ⅰ），13^2S-羟基脱镁叶绿素a（Ⅱ），脱镁叶绿素a（Ⅲ），棕榈酸（Ⅳ），反丁烯二酸（Ⅴ），对羟基苯甲酸（Ⅵ），4-痉基-3-甲氧基苯甲醛（Ⅶ）和甘露醇（Ⅷ）。8个化合物均为首次从该种海藻中得到，Ⅰ首次从海洋生物中获得，Ⅰ-Ⅲ具有诱导稻瘟霉菌丝变形活性和弱的肿瘤细胞毒性。     

太平洋侧花海葵中四个新神经酰胺的鉴定太平洋侧花海葵中四个新神经酰胺的鉴定

目的研究太平洋侧花海葵(Anthopleura pacifica)中的生物活性成分。方法采用稻瘟霉模型生物活性追踪方法,应用色谱技术进行分离,根据理化性质和波谱分析鉴定结构。结果得到了1个对稻瘟霉显示活性的组分,并鉴定为4个神经酰胺的混合物:N-羟乙基-N-十四酰-(2S,3R)-十八碳鞘氨醇-4(E),8(E)-二烯(a),N-羟乙基-N-(9Z-十六烯酰)-(2S,3R)-十八碳鞘氨醇-4(E),8(E)-二烯(b),N-羟乙基-N-十六酰-(2S,3R)-十八碳鞘氨醇-4(E),8(E)-二烯(c)和N-羟乙基-N-(13Z-二十二烯酰)-(2S,3R)-十八碳鞘氨醇-4(E),8(E)-二烯(d)。结论化合物a～d均为新的神经鞘氨醇化合物。     

Synthesis and structure-activity relationship of theasapogenol galactosides against Magnaporthe oryzae

Camellia oleifera is expected to provide alternative aglycone to synthesize some saponins similar to that from Schima superba with inhibitory activity against Magnaporthe oryzae. Eight theasapogenol galactosides were synthesized via protection of adjacent hydroxyl groups by a benzylidene for regioselective glycosylation in the multi-hydroxyl sapogenin. Water soluble galactose chain connected far from liposoluble end was a key group in inhibiting the growth of M. oryzea unless theasapogenol was modified by two galactosyl groups or by one galactosyl group and one benzylidene group. The amphoteric characteristics of saponin such as saccharide group number, distance between bipolar groups play an important role in inhibiting mycelium growth of M. oryzae.     

抗真菌中草药的初步筛选

目的从具有抗稻瘟霉活性的中草药中筛选具有抗病原真菌活性的中草药。方法采用管碟法 ,以白色念珠菌、申克氏孢子丝菌、絮状表皮癣菌为指示菌 ,进行抗真菌活性的筛选。结果筛选出 5种对絮状表皮癣菌有较好抑制活性的中药提取物。结论抗稻瘟霉模型与抗病原真菌活性具有较好的相关性 ,是一种很好的初筛模型。     

米曲霉(Aspergillus oryzae)对原薯蓣皂苷的生物转化

目的：制备呋甾皂苷的生物转化产物。方法：利用米曲霉对原薯蓣皂苷（化合物1）进行转化，转化产物用大孔吸附树脂柱色谱，C18反相硅胶柱色谱，硅胶柱色谱以及高效液相色谱等进行分离纯化，通过光谱分析（FAB-MS，^1H NMR，^13C NMR）鉴定化学结构。结果：得到了5个转化产物，包括3个呋甾皂苷和2个螺甾皂苷。结论：米曲霉可以在保留原薯蓣皂苷的26-位葡萄糖的情况下水解3，位末端1→2鼠李糖生成次生呋甾皂苷（化合物4）。米曲霉也可以去掉原薯蓣皂苷的22-位羟基生成20（22）双键的呋甾皂苷产物（化合物3和5），并且继续水解2昏位葡萄糖生成相应的螺甾皂苷（化合物2和6）。     

An Aspergillus oryzae CCAAT-binding protein, AoCP, is involved in the high-level expression of the Taka-amylase A gene

Aspergillus oryzae contains a nuclear protein designated AoCP, which binds specifically to a CCAAT sequence in the promoter region of the A. oryzae Taka-amylase A gene. A gene encoding a homologue of Aspergillus nidulans HAPC, a subunit of the A. nidulans CCAAT binding complex, was isolated from A. oryzae and designated AohapC. AoHAPC comprises 215 amino acids and shows 84% identity to A. nidulans HAPC. Transformation of the A. nidulans hapC deletion strain with the AohapC gene restored the CCAAT binding activity, resulting in both enhancement of taa gene expression and complementation for the poor growth phenotype of this strain. Furthermore, introduction of the AohapC gene also restored the expression of the A. nidulans eglA gene, encoding an endo-β-1,4-glucanase, in the deletion strain. These results indicate functional interchangeability of the genes from two species. Received: 5 February / 20 March 2000