共查询到20条相似文献,搜索用时 15 毫秒
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阿扎霉素B(Azalomycin B)研究进展 总被引:3,自引:0,他引:3
介绍阿扎霉素B的生物学来源,研究历史,主要理化性质和结构确定,同时阐述了阿扎霉素B的生物合成途径,构效关系,生物学特性和应用前景。 相似文献
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大鹏湾维生素B1、B12与赤潮 总被引:5,自引:0,他引:5
海湾及近海水域 ,因某些浮游生物爆发性繁殖引起的赤潮异常现象时有发生 ,已构成水产资源的严重破坏。为弄清赤潮发生的机理 ,已有许多作者进行过研究 ,现已知水温、盐度、溶解氧、pH、N、P ,以及Fe、Mn、Se等微量元素都是发生赤潮的重要环境因子[1 ]。近年来通过生态实验研究 ,发现维生素B1 、B1 2 (以下简称B1 、B1 2 )亦有促进赤潮生物生长繁殖的作用[2 ]。本文报道 1 991年对大鹏湾海域水样中B1 、B1 2 含量的测定结果 ,并对赤潮发生与其相关性进行探讨。1 采样布点和分析方法1 .1 采样布点大鹏湾盐田海域的S0 、S1… 相似文献
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Dr. L. Čelakovský 《Plant Systematics and Evolution》1893,43(4):143-147
Ohne ZusammenfassungDas Referat erstreckt sich auf den Zeitraum vom 1. Juli 1891 bis 10. März 1893. 相似文献
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B.B.Brodie博土,一个先驱药理学家和美国国家科学院院士,1989年2月28日逝世。生前是美国国立卫生研究院心脏研究所化学药理实验室的创始人和第一任主任。 相似文献
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Avital Schurr 《Life sciences》1982,30(13):1059-1063
That the enzyme, monoamine oxidase (E.C. 1.4.3.4. amine: O2 oxidoreductase, MAO) exists in multiple forms was first suggested by Johnston (1) who studied the effects of the irreversible inhibitor clorgyline on MAO. It has been proposed that MAO can be classified into two types, A and B, according to their inhibitor sensitivity and substrate specificity. Type A MAO was found to be solely responsible for the deamination of 5-hydroxytryptamine (5-HT) and shows high sensitivity to clorgyline, while type B MAO metabolizes 2-phenethylamine (PEA) and benzylamine (BA) and is less sensitive to clorgyline. Subsequently, it was shown that type B MAO is highly sensitive to the irreversible inhibitor deprenyl (2).Recently, the “multiple forms” concept has been questioned (3–5) mainly because of increasing evidence which is contradictory to some earlier findings. As an alternative, another hypothesis was put forward insinuating that MAO is an enzyme with multiple binding sites but only one molecular entity (3,4,6,7). This account will focus on some experimental findings accumulated mainly since 1978 and which, although equivocal, strongly support the “one molecular entity” hypothesis of MAO. 相似文献
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转录因子NF—КB/ⅠКB 总被引:9,自引:0,他引:9
可与kappa基因相结合的核因子NF-κB(nuclear factor-kappa gene binding)是研究得最为广泛的转录因子之一。该因子由Baltimore等人首先在B淋巴细胞发现,后来发现它广泛存在于其他类型细胞中。NF-κB具有如下特征:对外界信号的刺激反应迅速,控制广泛的基因表达,在免疫及炎症反应中起中心作用以及在胚胎发育中充当信号分子。本文就NF-κB/IκBα的结构、调节和功能作一综述。 相似文献
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Zhaoyu Liu Wencheng Zhang Miao Zhang Huaiping Zhu Cate Moriasi Ming-Hui Zou 《The Journal of biological chemistry》2015,290(4):2312-2320
Liver kinase B1 (LKB1), a serine/threonine kinase, is a tumor suppressor and metabolic regulator. Recent data suggest that LKB1 is essential in regulating homeostasis of hematopoietic cells and immune responses. However, its role in macrophages and innate immune system remains unclear. Here we report that macrophage LKB1 inhibits pro-inflammatory signaling in response to LPS. LPS-induced pro-inflammatory cytokines and pro-inflammatory enzymes were monitored in bone marrow-derived macrophages isolated from myeloid cell-specific LKB1 knock out mice and their wild type littermate control mice. LPS induced higher levels of pro-inflammatory cytokines and pro-inflammatory enzymes in bone marrow-derived macrophages from LKB1 KO than those from wild type mice. Consistently, LPS induced higher levels of NF-κB activation in LKB1-deficient macrophages than those in wild type. Further, LPS stimulation significantly increased LKB1 phosphorylation at serine 428, which promoted its binding to IκB kinaseβ (IKKβ), resulting in the inhibition of NF-κB. Finally, LPS injection caused higher levels of cytokine release and more severe tissue injury in the lung tissues of LKB1 KO mice than in those of control mice. We conclude that LKB1 inhibits LPS-induced NF-κB activation in macrophages. 相似文献
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病毒复制起始于病毒吸附蛋白与宿主细胞表面受体的特异性结合及此后由细胞介导的病毒穿入,而这些受体的特异性决定宿主细胞范围。应用单克隆抗体MAb854阻断,免疫沉淀法以及促衰退因子基因转染细胞等方法,发现细胞DAF是宿主细胞吸附柯萨奇病毒B1、B3和B5的受体,但这些病毒要侵入细胞及在胞内进行复制尚需依赖其他因子的存在。 相似文献
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Abstract 3-β-D-Ribofuranosylpyazolo[4,3-d]pyrimidines (formycins)1 modified in the heteroaromatic moiety are of biological interest as analogues of adenosine and guanosine, and have been the objects of intensive synthetic chemical effort by several groups.2-9 2′-Deoxynucleosides2c,2d,7b,13 and other analogties of the formycins modified in the sugar moiety10-12 are also of potential interest, but have been less extensively studied. Examples of the 2′-deoxyribonucleoside type known to date include the 2′-deoxy-6-thioguanosine analogue 1, the 2′-deoxyadenosine (dAdo) analogue 2 (2′-deoxyformycin A),10,13 and the 2-chloro-2′-deoxyadenosine analogue 3.7b Compound 2 was found to be 10-15 times more potent than 2′-deoxyadenosine as an inhibitor of the growth of S49 cells, a murine lymphoma line of T-cell origin.13 Activity depended on 5′- phosphorylation, since mutants lacking the enzymes adenosine kinase (AK) and deoxycytidine kinase (dCK) were insensitive to the drug. Furthermore, activity was comparable in the presence and absence of an AK inhibitor, suggesting that 2, unlike dAdo, may be a poor substrate for adenosine deaminase. That 5′-phosphorylation of 2 was mediated by AK rather than dCK was indicated by the fact that miitants lacking only dCK retained sensitivity. This contrasted with the behavior of dAdo, which is known to be n substrate for both AK and dCK.14 相似文献
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抗原-抗体的特异性结合是由抗体表面的抗原决定簇与抗原表面的表位基序间的特异性互补识别决定的。B细胞表位作图既包括B细胞抗原表位基序的鉴定(即确定抗原分子上被B细胞表面受体或抗体特异性识别并结合的氨基酸基序),也包括绘制抗原蛋白的全部或接近全部的B细胞表位基序在其一级或高级结构上的分布图谱的过程。B细胞表位作图是研发表位疫苗、治疗性表位抗体药物和建立疾病免疫诊断方法的重要前提。目前,已经建立了多种B细胞表位鉴定或绘制抗原蛋白B细胞表位图谱的实验方法。基于抗原-单抗复合物晶体结构的X-射线晶体学分析的B细胞表位作图和基于抗原蛋白或抗原片段的突变体库筛选技术的B细胞表位作图可以在氨基酸水平,甚至原子水平上揭示抗原分子上与单抗特异性结合的关键基序;其它B细胞表位作图方法(如基于ELISA的肽库筛选技术)常常只能获得包含B细胞表位的抗原性肽段,因而,很少用于最小表位基序的鉴定;而改良的生物合成肽法多用于B细胞表位的最小基序鉴定和精细作图。鉴于每种B细胞作图方法都存在各自的优势与不足,B细胞表位作图往往需要多种作图方法的有机结合。本文对目前常用的B细胞表位作图的实验方法及其在动物疫病防控中的应用进行综述,以期为研究者设计最佳的表位作图方案提供参考。 相似文献
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蛋白激酶B的研究进展 总被引:3,自引:1,他引:2
蛋白激酶B(PKB)发现于1991年,因其激酶活性区的氨基酸组成与蛋白激酶A(PKA)和蛋白激酶C(PKC)高度同源而得名。初步研究表明,PKB激酶活性的调节与细胞的生命活动密切相关,如PKB参与某些生长因子或淋巴因子诱导的靶细胞应答,影响胞内糖类的转运、糖原的合成及蛋白质的合成,抑制细胞凋亡等。PKB是机体维持正常生命活动的一个重要调节子。1.PKB的结构与分类1991年三个不同的研究小组同时发现PKB蛋白,并证明其激酶活性区的氨基酸组成与PKCε和PKA的同源性分别为73%和68%,因此将其命名为PKB或RACPK(re… 相似文献
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Ly-1 B细胞是近年来发现的一种淋巴细胞,它们既带有典型的B淋巴细胞表面抗原,又表达T淋巴细胞抗原——Ly-1分子与普。通B细胞相比,Ly-1 B细胞具有其独特的性质,参与自身抗体的分泌,并与慢性B淋巴细胞白血病的发生有关。本文报道了近年来对Ly-1B细胞的研究进展。 相似文献
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