Functions and mechanisms of plant histone deacetylases

Lysine acetylation, one of the major types of post-translational modifications, plays critical roles in regulating gene expression and protein function. Histone deacetylases(HDACs) are responsible for removing acetyl groups from lysines of both histone and non-histone proteins. While tremendous progress has been made in understanding the function and mechanism of HDACs in animals in the past two decades, nearly half of the HDAC studies in plants were reported within the past five years. In this review,we summarize the major findings on plant HDACs, with a focus on the model plant Arabidopsis thaliana, and highlight the components, regulatory mechanisms, and biological functions of HDAC complexes.     

Effect of anti-mosquito antibodies on the infectivity of the rodent malaria parasite Plasmodium berghei to Anopheles farauti

The effect of mouse anti-mosquito antibodies, present in the bloodmeal, on the infectivity of Plasmodium berghei Vincke to Anopheles farauti Laveran was investigated. Significantly fewer oocysts developed in mosquitoes feeding on mice immunized with sugar-fed mosquito midgut antigens than in mosquitoes feeding on control mice. Mosquitoes feeding on mice immunized with the midgut antigens derived from sugar-fed mosquitoes also showed reduced mortality and had lower infection rates than those fed on unimmunized mice. Blood-fed midgut antigen was less effective in producing these effects than sugar-fed midgut antigen.     

Molecular biology of wound-inducible proteinase inhibitors in plants

Abstract. The techniques of molecular biology are being employed to investigate at the gene level the systemically mediated, wound-induced accumulation of two defensive proteinase inhibitor proteins in plant leaves. These techniques have added a new dimension to biochemical and physiological studies already underway to understand the mechanism of induction by wounding. The acquisition of cDNAs from the RNAs coding for the two inhibitors facilitated studies of mRNA synthesis in leaves in response to wounding, and provided probes to obtain wound-inducible proteinase inhibitor genes from tomato ( Lycopersicon esculentum ) and potato (Solarium tuberosum) genomes. Successful transformations of tobacco plants with fused genes, containing the 5' and 3' regions of the inhibitor genes with the open reading frame of the chloramphenicol acelyltransferase ( cat ) gene, have provided a wound-inducible chloramphenicol acetyltransferase (CATase) activity with which to seek cis- and transacting elements that regulate wound-inducibility to help to understand the interaction of cytoplasmic and nuclear components of the intracellular communication systems that activate the proteinase inhibitor genes in response to wounding by insect pests.     

吗啡耐受大鼠心房心钠素的释放及其基因转录

本工作应用心钠素放射免疫测定和分子杂交技术首次发现,吗啡耐受大鼠血浆心钠素水平显著降低,心房内心钠素含量明显升高,同时心房内心钠素特异性mRNA水平也相应提高,提示在吗啡耐受时大鼠心房内心钠素的合成和贮存增加,释放减少。     

Production of DON-related trichothecenes byFusarium graminearum Schw from Krasnodarski krai of the USSR

34Fusarium graminearum Schw isolates produced 4-deoxynivalenol to form significant amounts of 4, 7 — dideoxynivalenol and lesser amounts of 4 — deoxynivalenol monoacetates on grain substratesin vitro. This is the first report on the capability a large group of naturally occurring isolates to produce 4,7-dideoxynivalenol. The average levels of 4,7-dideoxynivalenol on rice, corn, barley, and wheat as a substrate were respectively 26.8, 14.0, 12.8, and 10.5% of the level of 4-deoxynivalenol. 4, 7 — dideoxynivalenol was present in all examined naturally contaminated wheat kernel samples at levels of 1.7 to 7.9% of the level of 4-deoxynivalenol. These findings suggest that more attention should be given to the occurrence of 4,7-dideoxynivalenol in cereals.     

兔核移植胚胎起始发育的超微结构研究

对兔核移植胚胎起始发育的超微结构变化进行电镜观察,并与供体桑椹胚细胞,受体卵母细胞及同期正常受精胚胎的超微结构进行比较,“原核”期兔核移植胚胎的超微结构明显不同于供体桑椹胚细胞及受体卵母细胞的超微结构,而与同期正常受精胚胎相似,但有些核移植胚胎中皮质反应,及核仁和线粒体中出电子致密的网眼结构,与正常受精卵存在差别,分裂至２－细胞期时,与正常２－细胞胚超微结构更相似,结果提示,兔胚胎细胞核移植后,供     

激光诱变选育AC10菜用大青豆的研究报告

采用有性杂交和激光红宝石辐照交替进行,经１０多年的研究、试验、选育出一个蛋白质含量、脂肪含量特高的菜用大青豆－ＡＣ１０。ＡＣ１０菜用大青豆,系早熟、适应性广、抗逆性强、耐迟播、产量高、效益好的品种。全生育期１１０天、８０－８５天采摘青毛豆、单产鲜毛豆７００公斤以上,老豆单产１６０公斤左右。据农业部谷物测试中心分析,蛋白质含量４８．３２％,脂肪含量２１．３６％,合计６９．６８％。查新结果表明,为国内     

细菌Ⅵ型分泌系统效应蛋白的装配及功能的研究进展

蛋白分泌作为细胞之间传递信号的途径之一,在微生物生存竞争中也扮演着重要的角色。革兰氏阴性菌可以通过Ⅵ型分泌系统(type Ⅵ secretion system, T6SS)将效应蛋白传递至胞外或原核和真核微生物中,从而介导微生物间的竞争或宿主-细菌的相互作用,最终建立竞争优势。本文主要总结了T6SS的结构与组成,并重点对效应蛋白的装配以及其与免疫蛋白的作用机制的研究进展进行阐述,为以后靶向T6SS抗菌药物的研制提供新思路。     

正常大鼠肾脏细胞溶酶体膜的构成蛋白

溶酶体是细胞内对其吞噬之物质溶解及消化之主要场所,同时也是细胞自噬作用的主要细胞器。为了进一步了解此细胞器的功能与结构,我们采用免疫荧光标记法,通过5种针对大鼠肝细胞溶酶体膜蛋白的特异性单克隆抗体,对大鼠正常肾脏细胞溶酶体膜蛋白进行了标记,并通过NH_4Cl溶液对溶酶体作了膜膨胀处理,结果显示:(1)细胞内溶酶体膜蛋白是由多种蛋白所构成,其各种蛋白的含量是不同的;(2)所有溶酶体膜蛋白均表达于该细胞器之表面;(3)NH_4Cl溶液能有效地使溶酶体扩张,这将有和于进一步研究溶酶体的结构。     

亚美万代兰与多花兰种子发芽过程的扫描电镜观察

兰种子发芽之后形成原球茎与根状茎,前者以亚美万代兰,后者以多花兰为材料进行扫描电镜观察。多花兰种子发芽初期,与亚美万代兰相似,但分化子叶的能力较差,在暗培养下,只形成鳞片状叶,紧贴在根状茎的分生组织上。根状茎只有转入光培养才有茎叶分化。兰种子发芽时的毛状物,在电子显微镜下观察,其形态与根毛较接近。