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1.
王不留行环肽研究   总被引:9,自引:2,他引:7  
从中药王不留行(Vacariasegetalis)种子中分离并鉴定了4个环肽化合物,分别命名为王不留行环肽A,B,C,D(vaccarinsA,B,C,D),其中王不留行环肽A为新环肽化合物。其结构通过光谱和化学方法分别确定为:vaccarinA——cyclo-(Trp-Ala1-Gly-Val-Ala2),vaccarinB———cyclo-(Pro-Gly-Leu-Ser-Phe1-Ala-Phe2),vaccarinC———cyclo-(Pro1-Gly-Tyr-Val-Pro2-Leu-Trp),vacarinD———cyclo-(Pro-Val1-Trp-Ala-Gly-Val2).  相似文献   

2.
朱华  王洪  李保贵   《广西植物》1999,19(4):337-338
勐腊锡叶藤 新种 图1TetraceraxuiH-ZhuetH-Wang,sp-nov-pl-AffinisT-scandenti(Linn-)Merr-sedinflorescentiisminoribus,paucifloris,sepalismajoribus1-5cmlongisinstatufructuextusdensevillosis,staminibus1cmlongis,capsulismajoribushirsutis,1-5~2cmlongis,1-2~1-5cmlati…  相似文献   

3.
c—fos,c—myb和c—erbB—2与大鼠卵巢颗粒细胞生孕酮调?…   总被引:10,自引:3,他引:7  
目的和方法:用离体细胞体外孵育法,观察肥义c-fos、c-myb和c-erbB-2寡脱氧核苷酸(c-fos ODN、c-myb ODN和c-erbB-2 ODN)对hCG诱导大鼠颗粒细胞孕酮产生的影响。同时观察内皮素-1、γ-氨基丁酸和钙离子通道阻断剂维拉帕米对细胞中c-fos、c-myb和c-erbB-2蛋白的影响。结果:反义c-fos、c-myb和c-erbB-2 ODN均明显抑制hCG诱导颗  相似文献   

4.
云衫针层孔菌化学成分的研究   总被引:7,自引:1,他引:6  
从云衫针层孔菌Phellinus yamanoi(Tamz.)shaw分离得到12个化合物,借助光谱分析鉴定为:8,11,13-abietadien-18-oic acid(1),1,2-benzenedi-carboxylic acidbis(2-ethyl-hexyl)ester(2),ergosterol peroxide(3),ergosta 7,22(E)-iden-3-ol(4),ergosta 7,22(Z)-dien-3-ol(5),octadecanoic acid-1,3-propanediyl ester(6),octadecanoic acid(7),8(19),14-labdadien-13-ol(8),ergosta-4,6,8(14),22-tetraen-3-one(9),化合  相似文献   

5.
豚鼠气道及肺组织原癌基因表达与哮喘的相关研究   总被引:4,自引:0,他引:4  
目的:为研究原癌基因在哮喘发病中的作用。方法:以卵白蛋白致敏豚鼠建立哮喘模型,用Dot-blot、North-ern-blot分子杂交及免疫组化技术,分别观察正常及哮喘发作后豚鼠气道上皮及肺组织中原癌基因c-fos、c-myc的表达水平。结果:正常豚鼠气道及肺组织中c-fos及c-mycmRNA无或很少表达,哮喘发作后豚鼠气道上皮及肺组织中c-fos和c-mycmRNA表达明显增强,30min达高峰,发作后4h降至正常水平。地塞米松对c-fos及c-mycmR-NA有部分抑制作用。结论:原癌基因c-fos及c-myc在哮喘发病过程中可能起一定作用。  相似文献   

6.
非致病微生物在植物—病原菌协同进化中的作用   总被引:2,自引:0,他引:2  
非致病微生物在植物-病原菌协同进化中的作用单卫星(西北农业大学植保系,陕西杨陵712100)TheRoleofNon-pathogenicMicroorganismsinPlant-pathogenCoevolution¥ShanWeixing(Depart-mentofPlantProtection,NorthwesternAgriculturalUniversity,Yangling,Shaanxi712100).ChineseJournalofEcology,1993,12(6),54-59.Inviewofpresentproblemsassociatedwithplantdiseasecontrol,coupledwithrecentadvancesinbiolog-icalcontrolofplantdiseasesandplant-pathogeninteractions,theauthorpointedouttheimportanceofnon-pathogenicmicroorganismsinhabitingplantsurfacesinregulationofplant-pathoge  相似文献   

7.
几丁质酶和壳聚糖酶对部分乙酰化壳聚糖作用方式的比较   总被引:9,自引:0,他引:9  
通过对几丁质酶和壳聚糖酶降解部分乙酰化壳聚糖的作用方式的比较,得到几丁质酶切断壳聚糖的GlcNAc- GlcNAc 和GlcNAc- GlcN 或GlcN- GlcNAc 糖苷键,而壳聚糖酶切断壳聚糖的GlcN- GlcN 和GlcN- GlcNAc 或GlcNAc- GlcN 糖苷键,为得到较高聚合度的壳寡糖提供理论基础。  相似文献   

8.
洞庭湖滨湖湿地平原农村生态工程初步研究严斧,游有林,刘劲凡,卢源德,周为民(中国科学院生态环境研究中心系统生态室沅江课题组,大庸市416600)RuralEcologicalEngineeringonWetlandPlainofDongtingLakeside¥.YanFu;YouYoulin;LiuJinfan;LuYuande;ZhouWeimin(YuanjiangResearchGroup,ResearchCenterforEco-environmentalScience,A-cademiaSinica,Dayong416600).ChineseJournalofEcology,1993,12(2):45—48.AccordingtothemaintypesofresourcecombinationsonwetlandplainofDongtinglakeside,severaleco-logicalengineeringsincludinglakesidereed-forest,lowlandrice-fish-ramie,rnanure-forage-fuel,fish-pig-duckandf  相似文献   

9.
血管紧张素Ⅱ诱导左心室原癌基因c-fos和c-myc的表达   总被引:2,自引:0,他引:2  
本实验用Lanyendorff心脏灌流装置,探讨血管紧张素Ⅱ对左心室原癌基因c-fos和c-myc表达的作用。观察到血管紧张素Ⅱ能诱导左心室c-fos和c-myc的表达,c-fos表达早于c-myc表达,并呈量-效关系。这种作用可被血管紧张素Ⅱ受体拮抗剂saralasin所阻断。这些结果提示血管紧张素Ⅱ诱导的c-fos和c-myc的表达是受体介导的。TTX完全阻断血管紧张素Ⅱ诱导的c-fos表达。TTX对c-myc的表达无明显影响。  相似文献   

10.
^3H-TdR放射性转化细胞经1×10^-5mol/L Foskolin处理24h后,TGFa,c-myc,c-K-ras基因的mRNA表达下降;TGFβ,c-fos基因表达无明显变化。非转化细胞经相同条件处理,TGFa,TGFβ,c-myc及c-K-ras基因表达无显著改变。提示:Forskolin介导的转化细胞的生长抑制作用与TGFa,c-myc,c-K-ras基因的转录表达下降有关。  相似文献   

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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.  相似文献   

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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.  相似文献   

18.
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.  相似文献   

19.
肝癌中HBV和HCV基因和抗原的分布及意义   总被引:1,自引:0,他引:1  
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  相似文献   

20.
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.  相似文献   

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