鸡腿菇转化桑叶发酵液的降血糖作用研究

研究了鸡腿菇转化桑叶发酵液的降血糖作用,测定了糖尿病小鼠喂养鸡腿菇转化桑叶发酵液后血糖、血脂及肝脏、肾脏组织中的超氧化物岐化酶酶活等指标,并分析了发酵液中的成分。结果表明,鸡腿菇转化桑叶发酵液可以降低血清中血糖、果糖胺、甘油三酯、丙二醛含量,提高脏器中超氧化物岐化酶活性;同时,与未转化桑叶的发酵液相比,鸡腿菇转化桑叶发酵液中具有降血糖作用的黄酮和多酚含量显著增加高,进一步分离得到的4,5-二羟基,2-甲氧基-苯甲醛含量也显著提高。无论从功效还是发酵液成分变化都已说明鸡腿菇转化桑叶发酵液具有很好的降血糖作用,为药用真菌转化中药提高降血糖作用提供了参考。     

Multihydroxylation of ursolic acid by Pestalotiopsis microspora isolated from the medicinal plant Huperzia serrata

The structural modification of ursolic acid by an endophytic fungus Pestalotiopsis microspora, isolated from medicinal plant Huperzia serrata was reported for the first time. The structure diversity was very important for the SAR study of ursolic acid and its derivatives. Incubation of ursolic acid 1 with P. microspora afforded four metabolites: 3-oxo-15α, 30-dihydroxy-urs-12-en-28-oic acid (2), 3β, 15α-dihydroxy-urs-12-en-28-oic acid (3), 3β, 15α, 30- trihydroxy-urs-12-en-28-oic acid (4) and 3,4-seco-ursan-4,30-dihydroxy-12-en-3,28-dioic acid (5). All products were new compounds and their structures elucidation was mainly based on the spectroscopic data.     

Impacts of hypersaline water on the biotransformation and toxicity of fenthion on rainbow trout (Oncorhynchus mykiss), striped bass (Morone saxatilis X Morone chrysops) and tilapia (Oreochromis mossambicus)

Hypersaline water derived from agricultural practices primarily in arid landscapes can impact fisheries in streams receiving run-off from fields. Previous studies have indicated significant elevation in the toxicity of thio-ether pesticides by hypersaline water in certain species of euryhaline fish due to enhanced formation of sulfoxide metabolites which may be more toxic than the parent compounds. The objectives of this study were to evaluate the effects of salinity on the toxicity of the thio-ether organophosphate pesticide, fenthion in three species of euryhaline fish: rainbow trout (Oncorhynchus mykiss), striped bass (Morone saxatilis X Morone chrysops), tilapia (Oreochromis mossambicus) and determine whether a relationship was observed between toxicity and enantioselective sulfoxidation. Stereochemical formation and total sulfoxide formation did not mirror acute toxicity in the three species exposed in fresh or hypersaline conditions. Mortality of striped bass and rainbow trout due to fenthion exposure was enhanced by hypersaline treatments and a trend towards increased toxicity was observed in tilapia. In liver microsomes of rainbow trout, inhibition of cytochrome P450 (CYP) caused a respective 7- and 3-fold increase in sulfoxide formation in liver microsomes fresh and saltwater fish, and a significant increase in the formation of the (+)R-sulfoxide. CYP inhibition also caused a significant elevation of the (+)R-sulfoxide in freshwater striped bass, but not in hypersaline-treated bass. The results indicated contribution by CYP in the sulfoxidation of fenthion as well as the formation of other metabolites in all three species. In summary, hypersaline conditions impacted fenthion toxicity under conditions that appeared to be independent of fenthion sulfoxide formation indicating a much more complex mechanism of action for compounds with phosphorothioate and thio-ether structural features potentially involving multiple oxidative pathways.     

云杉木屑培养食用菌的研究

采用变色圈和降解实验,结果显示供试的8个菌株均有降解云杉木屑中木质素和纤维素的能力,纤维素和木质素被食用菌降解的程度与被降解的次序无关.结果显示,用云杉木屑栽培榆黄蘑、金针菇和平菇菌株,其菌丝生长较快,生物转化率较高;茶树菇和杏鲍菇菌株的菌丝生长速度较慢,生物转化率较低;木耳、裂褶菌和柳蘑菌株,菌丝生长速度很慢,几乎无法正常出菇.上述食用菌菌株的生物转化率与其对木质素、纤维素降解率的总和呈正相关.     

磁处理对锦鸡儿植物培养细胞生物转化反应的生物学效应研究

[目的]为磁处理在植物培养细胞的生物转化反应中的应用提供理论依据。[方法]以苯乙烯为底物,用磁处理后的锦鸡儿植物培养细胞做生物催化剂,研究磁处理对锦鸡儿植物培养细胞生物转化反应的生物学效应。[结果]研究发现有利于锦鸡儿细胞转化底物苯乙烯产生苯乙醛和苯乙酮的最佳磁处理条件是6mT/3min;有利于锦鸡儿细胞转化底物苯乙烯产生代谢产物的最佳磁处理条件是25mT/10min。[结论]不同磁处理条件对锦鸡儿植物培养细胞生物转化反应的生物学效应不同。     

利用生物转化技术改良中药材品质

就生物转化的机理、研究现状等作一综述,阐述了利用生物转化技术改良中药材品质的可行性,并指出了该技术在中药活性成分的开发与利用方面拥有广阔的应用前景。     

生物转化富铁、富锌、富硒鲜奶的研究

通过在奶牛饲料中添加微量元素铁、锌、硒，观察它们对奶牛产奶量、产奶品质以及牛奶中所含矿物质及微量元素的变化。结果表明：奶牛饲料中添加上述微量元素后，产奶量明显提高。且鲜奶中所含的铁、锌、硒都有不同程度的增加。     

生物拆分法制备D-天冬氨酸

[目的]利用L-天冬氨酸-β-脱羧酶生物转化拆分DL-天冬氨酸得到D-天冬氨酸的工艺过程。[方法]研究了碳源、有机氮源、转化过程pH值和转化温度对发酵液L-天冬氨酸-β-脱羧酶酶活力的影响,探讨了L-天冬氨酸-β-脱羧酶的热稳定性及L-丙氨酸对L-天冬氨酸-β-脱羧酶热稳定性的影响,并测定了拆分产物的主要指标。[结果]糖类对该酶的生物合成有明显的阻遏作用,而富马酸和苹果酸是很好的碳源物质。有机氮源中蛋白胨浓度对发酵液酶活力的影响较大,当牛肉膏浓度为0.2%,玉米浆为1.0%,蛋白胨为1.0%时发酵液酶活力可以达到最高。转化过程最适pH值为6～7。转化过程最适温度50℃。温度超过60℃酶失活比较严重。浓度6.0%以上的丙氨酸能显著提高转化过程中酶的热稳定性。[结论]利用D-天冬氨酸和L-丙氨酸的等电点的差异来分离提取D-天冬氨酸的制备工艺,其工艺简单,原料价格适宜,提取方便,工艺路线要比其他方法更便捷,更容易产业化。     

冬季平菇生产栽培料对比试验

比较了熟料、半熟料、生料3种不同栽培料对平菇的产量和生物转化率的影响。试验结果表明,半熟料栽培平菇的头三潮产量和生物转化率同熟料栽培基本相同;相对于熟料栽培,其优点是节约能源,便于操作,因此,在冬季平菇栽培中具有一定应用推广价值。     

链状亚历山大藻暴露下紫贻贝体内麻痹性贝毒蓄积转化规律

本研究将紫贻贝(Mytilus galloprovincialis)暴露于一株麻痹性贝类毒素(paralytic shellfish toxins, PSTs)优势产毒藻——链状亚历山大藻(Alexandrium catenella, GY-H25株),模拟现场赤潮藻密度,探究了紫贻贝内脏团和可食组织中蓄积代谢及生物转化过程,并通过蓄积代谢动力学,重点比较了不同细胞密度GY-H25对紫贻贝体内毒素蓄积代谢和转化情况的影响。结果显示,GY-H25生长及产毒稳定,PSTs组分主要为N-磺酰胺甲酰基类毒素(C1和C2),单细胞最高产毒能力为2.96 pg STXeq/cell。暴露实验中,紫贻贝对PSTs有较强的蓄积作用,2种暴露浓度下PSTs含量变化趋势一致,实验结束时,2种暴露组紫贻贝内脏团中PSTs均超过欧盟国际限量标准(800 μg STXeq/kg),但可食组织则均低于限量标准;比较发现,高浓度组紫贻贝内脏团最高蓄积浓度达到6 815.36 μg STXeq/kg,且高浓度组暴露期间平均蓄积速率为17.89%,显著高于低浓度组13.06%的蓄积速率。另外,紫贻贝对PSTs表现出较强的生物转化能力,在对C1、C2和GTX5三者的转化研究中发现,快速代谢时期和平稳期C2→GTX5的转化为GTX5生成的主要途径,同时期C1的相关转化中C1→GTX5途径超过C2→C1,致使C1整体占比减少。综合评估紫贻贝中PSTs转化产物和毒性当量因子(toxic equivalency factor, TEF),发现紫贻贝对PSTs代谢转化进一步促使高毒性GTX5的生成和占比提升,总体终端毒性升高,这也可能是秦皇岛紫贻贝中PSTs风险严峻的主要原因之一。因此,本研究有助于科学评估紫贻贝中PSTs风险,为建立区域性风险监测技术提供科学基础。