菜油基长链辣椒素酯小型化合物库的制备与初步生物活性

以脂肪酶在有机介质中催化食用菜油与香草醇直接转酯反应合成了一个含菜油酰基的长链辣椒素酯小型化合物库。反应条件：5mmol香草醇,2．5mmol食用菜油溶于100mL丙酮中,加入0．5g固定化脂肪酶（Nov0435）,置于30℃的摇床上以200r／min反应24h。分离固定化酶后,反应物以硅胶柱色谱分离,得到长链辣椒素酯小型库,收率34．1％。这个化合物库主要由亚麻酸香草醇酯（1）、亚油酸香草醇酯（2）、软脂酸香草醇酯（3）、油酸香草醇酯（4）、硬脂酸香草醇酯（5）、花生-烯酸香草醇酯（6）、芥酸香草醇酯（7）组成;它在50彬mL时对PPARv模型具有弱的激活作用,激活倍数为1．5。用制备性高效液相色谱对这个化合物库进行分离,得到化合物1—4、7,以1HNMR确证了结构,其中化合物7未见文献报道。     

天然辣椒素酯的酶促合成与生物活性

研究了天然辣椒素经化学．酶法转化为天然辣椒素酯类物质的方法。在30℃,香草醇、脂肪酸酯分别为50、75mmol／L的100mL脱水丙酮溶液,以1g固定化的脂肪酶Novozyme435为催化剂,摇床转速为200r／min条件下反应24h,目标化合物产率可达63％。经硅胶柱色谱分离纯化后,所得产物经质谱确证其含有天然辣椒素酯（capsiate）、二氢辣椒素酯（dihydrocapsiate）、降二氢辣椒素酯（nordihydrocapsiate）、高二氢辣椒素酯（homodi-hydrocapsiate）等。制备HPLC分离后得到辣椒素酯和二氢辣椒素酯,以^1HNMR及MS确定结构。活性测试表明辣椒素酯类物质具有激活PPARγ的生物活性及体外抑制乳腺癌细胞（MCF-7）和肝癌细胞（HepG2）的活性。     

非水溶剂中Rhizopus arrhizus脂肪酶催化合成三种酯的最佳条件(英文)

以少根根霉 (Rhizopusarrhizus)脂肪酶为催化剂 ,有机溶剂为反应介质 ,合成了 3种短链脂肪酸酯 .研究了反应温度、溶剂、底物浓度、底物摩尔比、吸水剂用量等因素对酯化反应的影响 .确定了3种酯的最佳合成条件 :(1)己酸乙酯 :反应温度为 4 0℃ ,环己烷为溶剂 ,0 2 5mol L底物浓度 ,酸醇摩尔比为 1∶1 2 ;(2 )乙酸异丙酯 :5 0℃ ,环己烷为溶剂 ,0 15mol L底物浓度 ,摩尔比为 1∶1;(3)乙酸异戊酯 :5 0℃ ,异辛烷为溶剂 ,0 2 0mol L底物浓度 ,摩尔比为 1∶1.三种酯合成时均需 0 12 5g ml的0 5nm分子筛为吸水剂 ,在 8h后 ,合成酯转化率达到 97%～ 99% .     

脂肪酶的固定化及棕榈酸抗坏血酸酯的合成研究

讨论了以固定化的黑曲霉脂肪酶为催化剂,以抗坏血酸和棕榈酸甲酯为底物的酯交 换反应及其影响因素.考察了反应温度、维生素C与棕榈酸的摩尔比、反应时间、溶剂的选 择、酶量等因素对催化棕榈酸抗坏血酸酯反应的影响规律.结果表明,摇床转速200r/min、 叔丁醇作溶剂、反应温度为55℃底物棕榈酸甲酯与Vc的摩尔比为2:1、反应时间为28h、脂肪酶浓度为4%,反应转化率为42.1%,产品纯度95%.     

有机相脂肪酶催化合成乙酸肉桂酯

对有机相中酶法催化合成乙酸肉桂酯的转酯化反应进行研究。结果发现:Candida anatarctic脂肪酶(Novozyme435)、根霉脂肪酶(Rhizopus niveus lipase)和荧光假单胞菌脂肪酶(Pseudomonas fluore lipase)均有较好的催化活性。同时考察各反应参数(温度、反应溶剂、体系水活度、酰化剂类型、肉桂醇与酰化剂摩尔比、肉桂醇浓度等)对脂肪酶Novozyme435合成乙酸肉桂酯反应的影响,确定了反应体系最优工艺条件:在10 mL甲基叔丁基醚中,肉桂醇200 mmol/L,n(肉桂醇)∶n(乙酸乙烯酯)=1∶1.5,初始水活度αw=0.84,温度35℃,酶加量0.02 g,反应3 h后肉桂醇转化率可达到99%,产物经质谱(MS)鉴定。固定化酶经过10个批次反应,反应转化率都保持在90%以上。     

生物法合成维生素C棕榈酸酯

研究了不同的脂肪酶在有机溶剂体系中催化合成L-维生素C棕榈酸酯的反应。针对维生素C在有机溶剂中溶解度较低这一问题,对催化合成维生素C棕榈酸酯反应的脂肪酶和反应介质进行比较,同时对影响合成维生素C棕榈酸酯反应的因素（温度、底物浓度、底物摩尔比、反应时间和酶量等）进行探讨,优化了反应条件：在10mL的丙酮中,1.094g棕榈酸与0.107g维生素C在酶量为20％（W/W, 固定化酶/维生素C）的固定化脂肪酶催化下,初始含0.4nm分子筛20%,温度为60℃,转速为200r/min,反应48h转化率可以达到80%,产物维生素C棕榈酸酯的浓度可达20g/L。     

超声辅助酶促合成丙二酸单对硝基苄酯

为了研究超声对固定化脂肪酶Novozym 435催化合成丙二酸单对硝基苄酯反应的影响。对超声辅助酶促酯化反应条件进行了优化,确定最佳反应条件:以甲苯为溶剂,固定化脂肪酶Novozym 435质量浓度为3.0 g/L,对硝基苄醇质量浓度为4.0 g/L,反应温度为30℃,反应时间为5 h,超声声强为0.8 W/cm2,超声频率为20 k Hz,丙二酸单对硝基苄酯收率为89.7%。与振荡水浴条件相比,超声辅助酶催化反应能强化传质,在反应温度降低15℃,时间缩短3 h和固定化酶浓度减少1.5 g/L的同时,产物收率增加了18.2%。超声作用下,Novozym 435重复使用性能较佳,应用于酯化反应8次后,丙二酸单对硝基苄酯收率为69.3%。     

非水相脂肪酶催化合成L-抗坏血酸棕榈酸酯的研究Ⅰ

对催化合成L-抗坏血酸棕榈酸酯反应的脂肪酶(NOVO435、MML、LIPOLASE、PPL)和反应介质进行比较,得出最佳酶种为NOVO435,最佳介质为叔戊醇;同时对影响合成L抗坏血酸棕榈酸酯反应的初速度的因素(转速、温度、水分含量、酶浓度和底物浓度)进行了探讨,确定了最适反应条件：转速为200r/min,温度为55℃,水分含量为0,酶浓度为12.5%。     

酶法合成医药级油酸失水山梨醇酯成功通过鉴定

由无锡轻工大学生物工程学院承担的江苏省科技厅应用基础研究项目“酶促生物转化医药级油酸失水山梨醇酯合成的研究”日前通过了由江苏省科技厅组织的鉴定。该成果从增强技术创新、提高我国生物转化产业的技术水平出发 ,以高纯油酸为原料 ,用微生物来源的脂肪酶在非水相减压体系中酶法合成和制备医药级油酸失水山梨醇酯。与传统方法相比 ,该技术采用固定化微生物脂肪酶酶促反应转化油酸山梨醇酯 ,具有反应条件温和、节省能耗 ,反应的特异性高 ,副产物少 ,安全性强 ,产品品质高等特点。其中固定化微生物脂肪酶酶促反应 1 0批次后的酶活力仍然…     

有机介质中脂肪酶催化转酯化反应拆分苯乙氰醇的研究

研究了有机相中脂肪酶催化苯乙氰醇的转酯化反应,拆分苯乙氰醇。考察了酶、溶剂、溶剂水含量、外加苯甲醛和苯甲酸以及底物浓度等因素对反应的影响,结果表明ZJU008号脂肪酶催化活性最高,经实验确定的最佳反应条件为：乙酸乙烯酯为反应物兼溶剂,利用分子筛去除溶剂中微量水分,40 ℃,200 r/min,酶量为10 mg/mL时的最佳底物浓度为200 mmol/L,在上述条件下反应20 h底物转化率为50%,e.e.值大于99%,能将苯乙氰醇有效拆分。外加苯甲醛和苯甲酸不利于反应的进行。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.