异丁香酚的生物转化及香兰素的合成

利用粘质沙雷氏菌菌株AB 90027产生的离体酶催化异丁香酚进行生物转化,结合TLC、GC、UV-VISI、R等测试手段对异丁香酚的转化途径进行了探讨,借助薄层扫描法对不同反应体系下产物香兰素的产率作了比较,并研究了可催化异丁香酚合成香兰素的酶在细胞的存在位置。结果表明:在酶的作用下,异丁香酚分别经过阿魏酸和香兰素两条途径开环降解成小分子,中间产物香兰素产率可达10.90%,催化合成香兰素的酶主要是胞外酶。     

“香料皇后”——天然香兰素生物合成的研究进展

香兰素是世界上最重要的香料之一,广泛应用在食品饮料、香精香料和医药工业等领域中,全球每年的需求量超过16 000 t.鉴于人们对纯天然绿色食品的追求日益增长,天然香兰素高效的生产方法也成为研究的热点.通过对各种香兰素生产方法的比较,明确提出微生物合成方法的主导地位,综述了香兰素的生物合成途径以及合成关键基因和酶等方面的研究进展,分析探讨了不同生物合成途径的优劣之处,并展望了利用微生物高产天然香兰素存在的瓶颈以及有潜力的发展方向.     

转化异丁香酚生成香草醛纺锤芽孢杆菌的筛选

以底物异丁香酚为唯一碳源从七壤中筛选获得了一株能高效转化异丁香酚生成香草醛的芽孢杆菌。根据生理生化特性及16SrRNA序列分析鉴定其属于纺锤芽孢杆菌（Bacillus fusiformis）,初步试验表明该菌能转化2％异丁香酚生成4．20g/L香草醚。     

Optimization of fermentation conditions for isoeugenol monooxygenase from Bacillus fusiformis CGMCC1347

对从土壤中筛选获得的纺锤芽孢杆菌CGMCC1347生产异丁香酚单加氧酶的发酵条件进行了单因素考察及正交实验优化,确定了最适的发酵摇瓶培养基组成和培养条件.在发酵培养基组成为尿素1 g/L,玉米浆55 g/L,K2HPO4 2g/L,MgSO4·7H2O 1 g/L,初始pH 7.5,发酵温度37℃,摇床转速180 r/min的条件下培养16h获得的细胞,能转化2％的异丁香酚生成2.49 g/L香兰素,异丁香酚单加氧酶酶活达3.79 U/L.     

纺锤芽孢杆菌CGMCC1347发酵生产异丁香酚单加氧酶的条件优化

对从土壤中筛选获得的纺锤芽孢杆菌CGMCCl347生产异丁香酚单加氧酶的发酵条件进行了单因素考察及正交实验优化,确定了最适的发酵摇瓶培养基组成和培养条件。在发酵培养基组成为尿素1g／L,玉米浆55g/L,K2HP042g／L,MgSO4·7H2O1g／L,初始pH7．5,发酵温度37℃,摇床转速180r／min的条件下培养16h获得的细胞,能转化2％的异丁香酚生成2．49g／L香兰素,异丁香酚单加氧酶酶活达3．79U／L。     

转化异丁香酚生成香草醛纺锤芽孢杆菌的筛选*

以底物异丁香酚为唯一碳源从土壤中筛选获得了一株能高效转化异丁香酚生成香草醛的芽孢杆菌。根据生理生化特性及16S rRNA序列分析鉴定其属于纺锤芽孢杆菌(Bacil-lus fusiformis),初步试验表明该菌能转化2%异丁香酚生成4.20 g/L香草醛。     

微生物转化合成香兰素

香兰素是食品工艺中应用最广泛的香料之一。本文首先探讨了能够合成香兰素的微生物,其次讨论了可用于合成转化香兰素的底物,阐述了测定香兰素的方法,最后对生物合成香兰素的前景进行了展望。     

两相体系中微生物法转化异丁香酚生成香草醛的研究

从土壤中筛选获得一株能耐受高浓度异丁香酚并高效转化生成香草醛的纺锤芽孢杆菌Bacillus fusiformis菌株CGMCC1347,研究了微生物细胞在异丁香酚-水两相体系中转化异丁香酚制备香草醛的过程。在异丁香酚体积分数60％,初始pH 4．0,温度37℃,转速180 r/min的条件下,转化72h,湿细胞质量浓度迭60 g/L时,香草醛质量浓度高达46.10 g/L。     

最新专利文摘

CN1712518:微生物转化异丁香酚制备香草醛的菌种和方法本发明涉及一株从土壤中筛选获得的纺锤芽孢杆菌CGMCC1347(SW-B9)及其培养发酵,并用于转化异丁香酚制备香草醛的方法。在优化条件下发酵培养,发酵液或游离细胞或其固定化细胞用于异丁香酚转化24~96 h,转化液中含香草酸2~4 g     

酶法转化异丁香酚制备香草醛的研究

研究了由大豆粗酶转化异丁香酚制备香草醛的方法,对转化条件进行了优化,并研究了H2O2、和吸附剂的影响,在优化后的条件下转化36h产物浓度达2．46g/L,摩尔转化率为13．27％。     

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.