阿扎霉素B(Azalomycin B)研究进展

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。     

大鹏湾维生素B1、B12与赤潮

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…     

B.B.Brodie(1907～1989)

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。     

Monoamine oxidase: To B or not to B?

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.     

转录因子NF—КB／ⅠКB

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。     

Ly-1 B淋巴细胞

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。     

B淋巴细胞刺激因子

B淋巴细胞刺激因子是新发现的属肿瘤坏死因子族的细胞因子。它是由单核细胞和巨噬细胞持续合成、分泌的,具有特异的激活B淋巴细胞,诱导B淋巴细胞增殖、分化为浆母细胞、分泌抗体,以及促进成熟B淋巴细胞在体内的存活等功能。在缺少B淋巴细胞刺激因子的情况下,可导致成熟B淋巴细胞缺乏。而异常过高表达B淋巴细胞刺激因子引起自身免疫性疾病,系统性红斑狼疮样症状。     

B淋巴细胞激活因子研究进展

B淋巴细胞刺激因子(BAFF)在B细胞免疫中具有促进B细胞的分化、成熟,调节体液中的抗体反应等重要的作用。然而过多的BANFF表达可使B细胞存活时间延长,B细胞数目增多,活性过高而导致自身免疫性疾病。BAFF与细胞表面的三种受体结合,执行着并不完全相同的功能。由于BAFF在B细胞发育、分化及白体免疫性疾病(特别是系统性红斑狼疮)中具有重要的作用,BAFF及其下游的信号转导因子成为疾病治疗的理想靶位。     

蛋白激酶B的研究进展

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…     

Synthesis of 2′-Deoxyformycin B and 2′-Deoxyoxoformycin B

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′-Deoxynucleosides^2c,2d,7b,13 and other analogties of the formycins modified in the sugar moiety^10-12 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     

柯萨奇病毒B1,B3和B5以促衰退因子作为细胞受体

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。     

Liver Kinase B1 Suppresses Lipopolysaccharide-induced Nuclear Factor κB (NF-κB) Activation in Macrophages

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.     

B计划的重要性

许多出色科学家都面临着丢掉饭碗的危险，而且是彻底地丢掉。     

血友病B的基因治疗

血友病B是一种凝血Ⅸ因子缺陷引起的X连锁隐性遗传的出血性疾病 .近年来 ,国内外学者在基因治疗方面取得的大量研究成果给血友病B患者带来了根治疾病的希望 .就血友病B的基因治疗研究进展及所存在的问题作一综述 .     

B型流感病毒研究进展

B型流感病毒为单股负链分节段RNA病毒,常在全球范围内以与A型流感病毒共流行的方式引起流感的局部暴发或季节性流行,对儿童、青少年、老人等特定人群易感,且感染儿童及青少年后引起的死亡率较高,给人类的公共卫生健康造成了严重威胁。B型流感病毒与A型相比更容易引发患者发生并发症,且其在流行季节造成的疾病负担甚至超过A型。近期,特别是2017年入冬后,B型流感病毒在我国的很多地区成为了引起流感发生的优势毒株,给人们的健康生活带来极大困扰。鉴于此,文中从B型流感病毒的结构、流行病学、免疫学及防治等方面进行了综述,旨在增强人们对该病毒的认识,为B型流感的防控提供借鉴和参考。     

B细胞刺激因子

<正> B细胞被抗原或抗Ig抗体等物质激活后增殖,并分化为大量分泌抗体的浆细胞。此乃体内抗体的唯一来源。足见B细胞在体液免疫应答中占有的重要位置。因此,B细胞的功能状态及其调节因素甚受医学界重视。B细胞的活化过程是一个受多种因素调节的连续而又复杂的过程,其中最重要的直接影响为T细胞和巨噬细胞产生的淋巴因子和单核因子的刺激作用。     

B病毒感染及防治

B病毒（B virus）,国际病毒分类委员会将其称为猕猴疱疹病毒1型（Cercopithecine herpesvirus 1,CeHV-1）,拉丁文名为猴疱疹病毒（Herpesvirus simiae）,属于疱疹病毒科、α疱疹病毒亚科、单纯疱疹病毒属.在35种非人灵长类疱疹病毒中,只有B病毒对人有致病性.     

B细胞超抗原

超抗原的特点是它们能与Ｔ细胞和Ｂ细胞抗原受体的抗原结合部位以外的位置与相应的受体结构。Ｂ细胞抗原则是与免疫球蛋白重链的Ｖ３家族结合。本文主要阐述了Ｂ细胞超抗原结构的分子基础。以及这种相互作用如何影响免疫应答的形成和在一些炎症与感染性疾病中它对免疫异常的发生起何种作用。