激素对楸子插穗内源激素含量和可溶性蛋白组成的影响

为了从分子水平上探究外源激素对楸子(Malus prunifolia)插穗中可溶性蛋白组成和内源激素含量变化的影响,利用SDS PAGE电泳技术和酶联免疫吸附分析法,研究了楸子插穗切口处的可溶性蛋白质变化和激素变化与生根的关系。结果表明:分子质量为83、72、65、52、43、39、31、28、26、22 ku的可溶性蛋白质等与生根有关。其中,分子质量为65、39、26、22 ku的蛋白是调控蛋白,当根原基分化时存在,不定根形成后即消失;分子质量为52、43、31、28 ku的蛋白是伴随不定根产生而新形成的蛋白,52 ku的蛋白是一种阻碍细胞分化的蛋白,对生根不利,其余蛋白可促进楸子插穗的生根。内源激素ZR在不定根产生过程中始终维持较高水平,而空白对照中这种趋势不明显。IAA不起主要作用,只起协同作用。GA在根原基分化时期起重要作用并与28 ku蛋白质合成有关。经过处理的插穗中ABA的含量均低于空白对照。说明不同外源激素的处理影响楸子插穗内部激素含量的变化,进而通过调控蛋白质的合成影响蛋白质的种类、数量以及出现时间的变化。     

The role of growth hormone and insulin-like growth factors in the immune system

Growth hormone (GH) and insulin-like growth factor I (IGF-I) can modulate the development and function of the immune system. In this chapter, we present data on the expression of receptors for GH and IGFs and the in vitro and in vivo effects of these proteins. We show that expression of GH and IGFs in the immune system opens up the possibility that these proteins are not only involved in endocrine control of the immune system but can also play a role as local growth and differentiation factors (cytokines). Endocrine control of GH could be direct or mediated via endocrine or autocrine/paracrine IGF-I. In addition, GH can act as an autocrine or paracrine factor itself. Furthermore, IGF-I in the immune system has been shown to be regulated by cytokines, such as interleukin-1 and interferon-γ, alluding to a cytokine-like function of IGF-I. In addition to data on the function of GH and IGF-I in the immune system, we present new findings which imply a possible function of IGF-II and IGF-binding proteins.     

Spasmin-like proteins in various ciliates revealed by antibody to purified spasmins ofCarchesium polypinum

Summary It was found that some ciliates,Stentor, Spirostomum andBlepharisma, which can contract rapidly like the stalks of Vorticellidae, have Ca²⁺-binding proteins that are very similar to spasmins, in the immunological sense. The presence of spasmins in other Protozoa and in some Metazoa was also investigated.     

Emerging connections between DNA methylation and histone acetylation

Modifications of both DNA and chromatin can affect gene expression and lead to gene silencing. Evidence of links between DNA methylation and histone hypoacetylation is accumulating. Several proteins that specifically bind to methylated DNA are associated with complexes that include histone deacetylases (HDACs). In addition, DNA methyltransferases of mammals appear to interact with HDACs. Experiments with animal cells have shown that HDACs are responsible for part of the repressive effect of DNA methylation. Evidence was found in Neurospora that protein acetylation can in some cases affect DNA methylation. The available data suggest that the roles of DNA methylation and histone hypoacetylation, and their relationship with each other, can vary, even within an organism. Some open questions in this emerging field that should be answered in the near future are discussed.     

Hydroxyproline-rich glycoproteins in plant reproductive tissues: structure, functions and regulation

The plant reproductive process of pollination involves a series of interactions between the male gametophyte (the pollen grain or pollen tube) and extracellular matrix (ECM) molecules secreted by different cell types along the pollen tube growth pathway in the female organ, the pistil. These interactions are believed to signal and regulate the pollen tube growth process to effect successful delivery of the sperm cells to the ovules where fertilization takes place. Hydroxyproline-rich glycoproteins secreted by plant cells are believed to play a broad range of functions, ranging from providing structural integrity to mediating cell-cell interactions and communication. The pistil and pollen tube ECM is enriched in these highly glycosylated proteins. Our discussions here will focus on a number of these proteins for which most information has been available, from Nicotiana tabacum, its self-incompatible relative N. alata, and Zea mays. In addition, the regulation of the synthesis and glyco-modification of one of these proteins, TTS (transmitting tissue-specific) protein from N. tabacum will be discussed in the light of how differential glycosylation may be used to regulate molecular interactions within the ECM.     

动物血清刺激下的有毒甲藻生长研究

目前有关Pfiesteria piscicida Steindinger et Burkholder的摄食行为研究已有相当多的报道，然而这种生物是如何应用蛋白的还没有人做过研究．我们研究了P．piscicida依赖于血清蛋白的生长能力，发现不管添不添加其捕食者Rhodomonas sp．，仅仅1h后，添加了动物血清的实验组就比未添加血清的对照组显示出明显出更快的生长速率，这种活跃的生长至少持续了4h．当添加了异硫氰酸荧光素的共扼免疫蛋白后，在P．piscicida的细胞中检测到了荧光；第1个小时只能检测到微弱的荧光。此后荧光逐渐增强，到3～4h达到最强．此外．我们还进一步通过蛋白质印迹法来验证P．piscicida细胞对血清蛋白质的吸收．本研究首次提供了沟鞭藻能够消化利用蛋白质的直接证据，并且发现P．piscicida生长响应与动物蛋白的添加几乎是同步的．尽管细胞快速生长机制还有待进一步研究。但我们的发现可能解释了P．piscicida是如何得益于其吞噬摄食方式及如何在鱼类出现时作出快速反应的．     

抗人体艾滋病毒的核糖体失活蛋白

核糖体失活蛋白是一类作用于真核细胞核糖体，抑制蛋白质合成的毒蛋白。近年来，发现核糖体失活蛋白能抑制急性感染的Ｔ细胞和慢性感染的单核巨噬细胞中ＨＩＶ的复制和增殖，其作用方式独特，不产生耐药性。至少已知８种核糖体失活蛋白有抗ＨＩＶ的作用。这些核糖体失活蛋白的序列有一定的同源性     

诸葛菜花粉不同发育时期特异性蛋白多肽研究

对诸葛菜(Orychophagmus violaceus)花粉不同发育时期蛋白多肽进行双向电泳，结果发现花粉发育的3个时期出现蛋白多肽点的数量为：单核期121个，二核期192个，三核期275个,3个时期共有(指等电点和分子量相同)的蛋白多肽点有100个．各时期特有的蛋白多肽点分别为：单核期9个，二核期15个，三核期110个。三核期蛋白多肽点数量和特有蛋白多肽点数量的大量增加，说明诸葛菜花粉发育晚期蛋白表达异常活跃，为受精提供了物质上的准备，同时还发现不同发育时期的花粉，其相应蛋白多肽的含量有增有减。     

Phylogenetic relationship of organisms obtained by ribosomal protein comparison

The evolutionary relationships of ribosomal proteins from eubacteria, archaea, eukaryotes, chloroplasts and mitochondria were examined by their degree of conservation, their structural and functional properties and by the occurrence of conserved structural elements. The structural domains formed by the different protein families were studied. The occurrence of monophyletic groups was investigated for each protein family within the archaea. Phylogenetic trees were constructed between these organisms and together with the homologous sequences of the other phylogenetic domains. All organisms belonging to the archaea clearly formed a monophyletic group. The conserved sequence motifs were checked for the potential to form similar secondary structural elements. Received 24 October 1996; accepted 30 October 1996     

蛋白质分离与制备的新方法：电泳及等电聚焦

本文介绍了近二十年来分离蛋白质的新方法及制备型设备的进展.共分三大类:即电泳、场流分级和等电聚焦。介绍了其中的技术关键,如建立pH梯度的方法、流动方向与电场垂直的新概念以及近10年来发展的多种类型的制备装置。其中一些较好的装置的处理能力已超过制备型的凝胶色谱和亲和色谱装置,达到了每天分离几克到几百克蛋白质的水平。