蒜片微波真空干燥过程中硫代亚磺酸酯变化机理

硫代亚磺酸酯是大蒜中的生物活性物质.本文研究了蒜片微波真空干燥过程中硫代亚磺酸酯含量变化的规律及其机理.结果表明,硫代亚磺酸酯保留率与干燥过程中蒜氨酸酶活力呈正相关,蒜氨酸酶活力与干燥过程中蒜片内部平均温度呈负相关,而蒜片内部平均温度与真空度和蒜片水分含量有关,真空度越高内部平均温度越低,水分含量越低则内部平均温度越高.     

一种方便快速检测蒜素的方法

基于硝基硫代苯甲酸 ( 2 nitro 5 thiobenzoate,NTB)与硫代亚磺酸脂 (Thiosulfinates)反应 ,对蒜素 (allicin)进行检测。一分子allicin与两分子NTB进行反应 ,形成NTB二硫键衍生物 ,通过吸光值 (A₄₁₂ )的测定来计算蒜素 (allicin)含量。     

基于愈创木酚的生物基固化剂对环氧树脂的固化性质

将生物基化合物丁二酸酐和具有芳环刚性结构的愈创木酚通过傅克反应制备得到同时具有酚羟基和羧酸基团的化合物3-(4-羟基-3-甲氧基苯甲酰)丙酸(GSA)。结果发现:GSA可以作为环氧树脂的固化剂,与常用的石油基固化剂4,4-二氨基二苯砜(DDS)相比,GSA的固化体系具有更高的固化反应速率常数。在相同的固化条件下,用GSA固化得到的双酚A型环氧树脂的玻璃化转变温度比DDS固化得到的高了40℃,5%热失重温度提高了107.8℃,显示出了更为优异的热稳定性。本研究对构筑高性能生物基高分子材料提供了借鉴思路。     

外源H2O2胁迫对大蒜试管苗玻璃化的影响

以大蒜品种‘二水早’为材料,研究不同浓度外源H2O2胁迫对大蒜试管苗的玻璃化发生及生理生化变化的影响.结果表明,在不同浓度外源H2O2处理下,大蒜玻璃化试管苗百分率、组织含水量、MDA含量、电解质渗透率、SOD和POD活性均高于对照,且随H2O2浓度的增加而升高,叶绿素含量则表现相反的趋势;在同一H2O2浓度下,大蒜玻璃化试管苗的组织含水量、MDA含量、电解质渗透率、SOD、POD和CAT活性均显著高于大蒜正常试管苗,叶绿素含量低于正常试管苗.研究发现,外源H2O2胁迫对大蒜试管苗玻璃化有促进作用.     

含硫香料——硫代芳樟醇及其衍生物的合成研究

本文对香叶醇转化为硫代芳樟醇(4)及其衍生物的合成方法进行了研究。香叶醇与N,N-二甲基琉代氨基甲酰氯反应生成N,N—二甲基琉代氨基甲酸-O-香叶基酯(5),(5)通过[3,3]-σ迁移反应转变成N,N-二甲基硫代氨基甲酸-S-芳樟基酯(6),(6)进一步还原得到硫代芳樟醇(4)。(4)转变成衍生物硫代芳樟醇乙酸酯(7a)及芳樟基甲基疏醚(7b)。(4)及(7b)在高度稀释时具有愉快的热带水果香味。     

4-硫代胸腺嘧和4-硫胸腺嘧啶脱氧核苷结构的光谱研究

采用拉曼和 UV 光谱研究了抗癌药物4-硫代胸腺嘧和4-硫胸腺嘧啶脱氧核苷的特征结构,确定了药物在酸性、中性和碱性环境下的结构变化。研究结果表明,在酸性和中性溶液中,4-硫代胸腺嘧和4-硫胸腺嘧啶脱氧核苷被强烈质子化,而在碱性环境中则是去质子化,同时,4-硫胸腺嘧啶脱氧核苷的质子化和去质子化比4-硫代胸腺嘧弱,说明氢键的结合对4-硫代胸腺嘧的 NH 质子和溶液分子之间的相互作用具有重要影响。     

4-硫代胸腺嘧和4-硫胸腺嘧啶脱氧核苷结构的光谱研究（英文）

采用拉曼和UV光谱研究了抗癌药物4-硫代胸腺嘧和4-硫胸腺嘧啶脱氧核苷的特征结构,确定了药物在酸性、中性和碱性环境下的结构变化。研究结果表明,在酸性和中性溶液中,4-硫代胸腺嘧和4-硫胸腺嘧啶脱氧核苷被强烈质子化,而在碱性环境中则是去质子化,同时,4-硫胸腺嘧啶脱氧核苷的质子化和去质子化比4-硫代胸腺嘧弱,说明氢键的结合对4-硫代胸腺嘧的NH质子和溶液分子之间的相互作用具有重要影响。     

长期施肥对红壤和黑土硫形态演变的影响

以红壤和黑土肥力与肥料效益监测站土壤为研究对象,研究了长期(21年)不同施肥(不施肥对照、施用氮磷钾、氮磷钾配施有机肥)处理下,表层(0～20 cm)和亚表层(20～40 cm)土壤硫素形态组成、分布及演变规律.结果表明: 长期施用化肥及化肥配施有机肥处理下,表层土壤全硫比对照分别增加42%、33%(红壤)和6%、76%(黑土);除红壤氮磷钾处理外,亚表层土壤全硫受施肥影响较小,且明显低于相应表层土壤.有效硫和盐酸可提取态硫分别为红壤和黑土中的主要无机硫形态.施用化肥及化肥配施有机肥的红壤表层有效硫比对照分别增加了447%和102%,并促进了有效硫向亚表层的迁移、累积;而施用化肥及化肥配施有机肥处理的黑土表层有效硫仅比对照分别增加54%和93%,其对亚表层土壤有效硫的影响也不大.有机硫形态在两种土壤中都以酯键硫和残渣态硫为主.长期施肥影响下的表层和亚表层土壤中残渣态硫含量比对照分别增加了32%和55%以上;土壤中性质相对活跃的酯键硫和碳键硫受施肥影响不显著,而与土壤有机碳含量呈显著正相关关系(P<0.05).此外,长期施肥试验表明大气硫沉降对土壤硫素输入的影响值得重视.     

重组人尿激酶原冻干产品的稳定性

目的：探讨重组人尿激酶原（rhPro-UK）冻干产品的稳定性。方法：采用S-2444发色底物法测定贮存在4℃和-20℃的rhPro-UK冻干产品的活性、单链比例随时间的变化规律;用SDS-PAGE及RP-HPLC肽图分析贮存在-20℃的rhPro-UK冻干产品的结构与组成的变化。结果：4℃保存3年后的rhPro-UK冻干产品的总活性和单链比例基本没有变化,但随着贮存时间的延长,有部分产品降解,如贮存78个月的样品,总活性可降低13％～15％;-20℃保存78个月后,rhPro-UK冻干产品的总活性和单链比例未见明显变化。SDS-PAGE及RP-HPLC肽图图谱显示,-20℃贮存78个月后的rhPro-UK冻干产品的组成和结构没有变化。结论：rhPro-UK冻干产品在4℃的贮存寿命可达3年;长期贮存于-20℃的rhPro-UK冻干产品,其总活性、单链比例及结构组成非常稳定。     

41801的杀虫活性及其对胆碱酯酶的抑制

二烷氧基二硫代磷酸酯是有机磷杀虫剂中的一个很重要类型,很多重要的农药品种属于此类,如甲拌磷、乙拌磷等等。但不对称的二硫代(醇式)磷酸酯的研究工作,还是近几年才出现的一个较新领域。Oswald等(1978)合成了一系列O,S-二烷基-S-(β-烃硫基)烷基二硫代磷酸酯及其氧化物,发现这些化合物对鳞翅目害虫具有很高的杀虫活性。1981年我们也合成一系列不对称二硫代(醇式)磷酸酯类化     

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.