高速逆流色谱法制备灵芝萜烯酮醇

本研究建立一种从灵芝子实体提取物中快速制备灵芝萜烯酮醇的方法.以沪农灵芝1号子实体为原料,经乙醇提取、D101大孔树脂富集后,再经一次正相色谱柱层析,获得富含灵芝萜烯酮醇的流分.采用高速逆流色谱法对该流分进行分离,优化分离条件,获得的最佳条件为:溶剂体系为正己烷-乙酸乙酯-甲醇-水(V/V/V/V,12∶24∶18∶9...     

Purification, Biochemical and Immunological Characterization of Acid Invertases from Apple Fruit

The soluble acid invertase (SAI) and cell wall-bound invertase (CWI) were purified from apple fruit to apparent electrophoretic homogeneity. Based on sequencing, substrate specificity, and immunoblotting assay, the purified enzymes were identified to be two isoforms of acid invertase (β-fructosidase; EC 3.2.1.26). The SAI and CWI have the same apparent molecular mass with a holoenzyme of molecular mass of 220 kDa composed of 50 kDa subunits. The SAI has a lower Km value for sucrose and higher Km for raffinose compared with CWI. These acid invertases differ from those in other plants in some of their biochemical properties, such as the extremely high Km value for raffinose, no hydrolytic activity for stachyose, and a mixed form of inhibition by fructose to their activity. The antibodies directed against the SAI and CWI recognized, from the crude extract, three polypeptides with a molecular mass of 50, 68, and 30 kDa, respectively.These results provide a substantial basis for the further studies of the acid invertases in apple fruit.     

Effects of Artemisinin Derivative on the Growth Metabolism of <Emphasis Type="Italic">Tetrahymena thermophila</Emphasis> BF5 Based on Expression of Thermokinetics

The toxic effects of artesunate and dihydroartemisinin on the growth metabolism of Tetrahymena thermophila BF5 were studied by microcalorimetry. The results showed that: (1) low concentrations of artesunate (≤1 mg L⁻¹) and dihydroartemisinin (≤ 2 mg L⁻¹) promoted the growth metabolism of T. thermophila BF5, whereas high concentrations of artesunate (1–60 mg L⁻¹) and dihydroartemisinin (2–60 mg L⁻¹) inhibited its growth; (2) the half inhibition concentrations IC₅₀ of artesunate and dihydroartemisinin were 17.5817 and 9.5089 mg L⁻¹, respectively. It was concluded that the inhibition of dihydroartemisinin was stronger than that of artesunate.     

江豚表皮超微结构的研究

本文用透射电镜和扫描电镜对捕自莱州湾的两头江豚表皮的超微结构作了观察。见其表皮中MCG的板层结构与海豚的有所不同,MCG内容物排出到细胞间隙形成表皮屏障。其黑素颗粒可能通过黑素细胞的突起与角蛋白细胞相接触处胞膜的消失出现缺口的方式输入角蛋白细胞。并对江豚表皮的不全角化现象等问题进行了讨论。     

热带假丝酵母高效利用甘油研究

目的:热带假丝酵母以油脂为底物发酵时会产生副产物甘油,研究对热带假丝酵母gk基因进行过表达,将副产物甘油转化为能量,提高油脂转化利用效率。方法:以热带假丝酵母Candida tropicalis 1798中的甘油激酶(gk)为研究对象,利用PCR技术获得同源臂基因gkpR,通过一步法无缝克隆将同源臂和G418抗性基因(kanr)连接至pPICzαA载体,同时将解脂假丝酵母Candida lipolytica 1457中的启动子基因pGAP无缝连接至载体中的gkpR,构成质粒pPICzαA-gkp,并电转化至C.tropicalis 1798感受态细胞中,通过一次同源单交换,将启动子pGK替换为pGAP。结果:经过G418抗性筛选和PCR鉴定,成功获得pGAP基因替换菌株C.tropicalis 1798-gkPr;发酵验证结果显示,启动子基因替换C.tropicalis 1798在以甘油为底物培养时重组菌OD600值比野生型菌株高46.4%,重组菌培养基中甘油剩余量比野生菌降低56.1%,表明启动子替换能促进C.tropicalis1798对甘油的吸收利用。此外,以油脂为底物进行发酵实验时还发现重组菌产长链二元酸的量比野生菌提高32.7%。结论:通过启动子替换手段构建的重组菌C.tropicalis 1798-gkPr,提高了热带假丝酵母对油脂组分中甘油成分的利用效率。     

丹参线粒体和叶绿体微卫星标记开发及多样性分析

该研究通过生物信息学方法,对丹参线粒体、叶绿体基因组序列进行SSR位点搜索,利用Primer3.0软件在线设计SSR引物,通过PCR扩增,筛选出扩增效果好、多态性高的10对cpSSR引物和13对mtSSR引物,用于分析61份丹参品种的遗传多样性和鼠尾草属植物种间的通用性。结果显示：（1）从2条基因组序列中搜索到32个cpSSR位点和24个mtSSR位点,其中叶绿体单核苷酸的重复序列最多为31个,占96.9%,重复类型中以A/T形式的微卫星最为丰富。（2）23对SSR引物共检测出46个等位基因,平均每个SSR位点等位基因数是2个,有效等位基因数为1.566;预期杂合度(H_e)为0.346,高于双子叶植物的平均水平（H_e=0.190）;多态信息含量（PIC）为0.278,大于0.250小于0.500;Shannons信息指数为0.519,表明所采集的丹参呈中等水平的遗传多样性。（3）聚类分析表明,61份丹参材料的遗传相似系数在0.54~0.96之间,并在遗传相似系数为0.64处将 61份丹参分为6个亚群：四川、山东和安徽省的丹参聚集在Ⅰ和Ⅱ亚群中,说明四川中江、山东和安徽地区的丹参亲缘关系较近,而来源于四川中江的丹参分布于所有亚群,表明四川中江的丹参具有丰富的多态性。（4）通用性检测结果显示,11对mtSSR引物在9种鼠尾草属中的平均通用性比率为64.63%,通用性较高;9对cpSSR引物在10种鼠尾草属中的平均通用性比率为44.66%,通用性较低;引物cp5p、cp8p和cp10p在野芝麻亚科植物属间的通用性较好。研究表明,开发的23对SSR引物在鼠尾草属内具有很好的适用性,可以为该属种间的亲缘关系和种内遗传分化研究提供分子依据。     

光照-温度交互作用及不同氮源对拟柱孢藻生长的影响

为探讨不同环境因子对拟柱孢藻(Cylindrospermopsis raciborskii)生长的影响,对从广东省镇海水库分离的2株拟柱孢藻在不同的温度和光照组合,及不同氮源条件下的生长进行了研究。结果表明,在3种光强下,拟柱孢藻N1和N8藻株的生长随温度的上升而增加,均在28℃高光强下达到最大比生长速率,而N8藻株对低温的适应能力要高于N1藻株。拟柱孢藻N1和N8在各硝态氮浓度下均能正常生长,但仅能在中低浓度的铵态氮和尿素氮中生长,高浓度(128~247 mg L–1)的铵态氮和尿素氮会显著抑制藻细胞生长;在3种氮源下,N1藻株的比生长速率均显著大于N8藻株,这说明N1藻株对不同氮源的利用能力要高于N8藻株。因此,广东省的拟柱孢藻具株系多样性,喜好高温,适应较宽的光照范围,并可利用多种氮源用于生长,这可能是该地区拟柱孢藻水华频发的原因。