Genome-wide analysis of the RING finger gene family in apple

The RING finger protein family plays a crucial role in plant growth and development and in response to biotic and abiotic stresses. However, no detailed information concerning this family is available for apple (Malus × domestica L. Borkh) due to the limited information on whole genome sequences. In this study, 688 RING domains in 663 predicted proteins were identified in apple. Based on the spacing between metal ligands or substitutions at one or more of the metal ligand positions, nine RING types were identified: RING-H2, RING-HC, RING-C2, RING-v, RING-D, RING-S/T, RING-G, RING-mH2, and RING-mHC, in which the first seven types were described previously in Arabidopsis, while the latter two were newly identified in apple. Proteins containing RING finger motifs were further classified into 57 groups according to the different known or unknown domains outside the RING domains. A total of 643 retrieved proteins appear to be distributed over all 17 linkage groups with different densities. Microarray and expressed sequence tag data revealed that only a few of these RING finger proteins may be involved in fruit development. As a first step towards genome-wide analyses of the RING-containing genes in apple, our results provide valuable information for understanding the classification and putative functions of the RING finger gene family in higher plants.     

猪鼻支原体P37蛋白相互作用蛋白的筛选与鉴定

既往工作表明,胃癌组织中有较高的猪鼻支原体感染率,猪鼻支原体的主要膜蛋白P37能够诱导外周血单核细胞释放肿瘤坏死因子（TNF）.为了深入研究P37的作用机制,利用酵母双杂交系统筛选与P37蛋白相互作用的蛋白质分子.首先,将编码P37全长的cDNA克隆到pGBKT7载体中,构建“诱饵”表达载体pGBKT7-p37,以此筛选人胎盘组织cDNA表达文库.在2.6×10⁶个克隆中,筛选到一株能与P37相互作用的阳性克隆,序列测定表明,该阳性克隆编码人视网膜色素上皮细胞蛋白（Norpeg蛋白）.在此基础上经GST-Pull Down实验,进一步证实Norpeg蛋白确能与P37相互作用,为进一步研究P37对细胞的作用机制奠定了基础.     

肿瘤及胚胎组织特异表达蛋白CEP65相互作用蛋白的筛选与鉴定

CEP65蛋白(cancer and embryo expression protein 65)为肿瘤单克隆抗体3H11所识别的抗原分子, RT-PCR及RNA印迹检测表明, CEP65蛋白表达于肿瘤及胚胎组织.为了研究CEP65在肿瘤发生中的作用机制,以CEP65为诱饵蛋白,通过酵母双杂交体系筛选人胚胎组织cDNA表达文库. 从5.2×10⁶个克隆中筛选得到14个阳性克隆,并在酵母体系中通过不同方法得到验证.在此基础上,选取在双杂交中作用明显的51号克隆,与CEP65作GST pull-down实验, 结果证明, CEP65与51号阳性克隆蛋白确能相互作用. 生物信息学分析发现, CEP65与51号阳性克隆蛋白相互作用, 可能通过WW结构域或者蛋白激酶C对细胞的增殖与分化起到调节作用.     

Antisense suppression of an acid invertase gene (MAI1) in muskmelon alters plant growth and fruit development

To unravel the roles of soluble acid invertase in muskmelon (Cucumis melo L.), its activity in transgenic muskmelon plants was reduced by an antisense approach. For this purpose, a 1038 bp cDNA fragment of muskmelon soluble acid invertase was expressed in antisense orientation behind the 35S promoter of the cauliflower mosaic virus. The phenotype of the antisense plants clearly differed from that of control plants. The transgenic plant leaves were markedly smaller, and the stems were obviously thinner. Transmission electron microscopy revealed that degradation of the chloroplast membrane occurred in transgenic leaves and the number of grana in the chloroplast was significantly reduced, suggesting that the slow growth and weaker phenotype of the transgenic plants may be due to damage to the chloroplast ultrastructure, which in turn resulted in a decrease in net photosynthetic rate. The sucrose concentration increased and levels of acid invertase decreased in transgenic fruit, and the fruit size was 60% smaller than that of the control. In addition, transgenic fruit reached full-slip at 25 d after pollination (DAP), approximately 5 d before the control fruit (full-slip at 30 DAP), and this accelerated maturity correlated with a dramatic elevation of ethylene production at the later stages of fruit development. Together, these results suggest that soluble acid invertase not only plays an important role during muskmelon plant and fruit development but also controls the sucrose content in muskmelon fruit.     

版纳小型猪近交系椎骨、肋骨的形态及生物力学研究

本研究观察了版纳小型猪近交系椎骨、肋骨的解剖学、组织学形态,并对其腰椎进行轴向载荷压缩试验。小型猪椎骨及肋骨在解剖学、组织学方面与人近似,其腰椎能承受人类正常生理载荷。因此,版纳小型猪椎骨、肋骨可以作为异种骨移植的材料。     

人源分泌型血管内皮细胞生长因子受体flt-1（Ⅰ～Ⅳ区）的基因克隆及其腺病毒载体的构建和表达

肿瘤的生长、转移与血管形成密切相关,利用基因治疗的方法将抗血管形成的因子导入体内是目前肿瘤生物治疗研究的重要策略.血管内皮细胞生长因子（VEGF）在血管生成中起重要作用,因此阻断VEGF与相应受体的结合成为抗血管形成的重要靶点.通过RT-PCR从人脐静脉内皮细胞克隆了VEGF受体Flt-1的信号肽及胞外Ⅰ～Ⅳ区cDNA,即可溶性sFlt-1的cDNA片段.利用Ad-Easy体系, 在细菌BJ5183中同源重组后,转染包装细胞293,成功包装出重组flt-1腺病毒,利用它可有效地感染低分化胃黏液腺癌细胞株MGC803.经RT-PCR,免疫沉淀及免疫印迹等不同方法检测表明,被感染细胞能表达并分泌Flt-1的胞外区蛋白,为后续进行抗肿瘤血管形成的基因治疗研究奠定了基础.     

不同季节温升条件下余氯对桡足类的毒性

为探明桡足类对滨海电厂冷却水中余氯的忍受能力,在各季节于室内对采自乐清湾的12种桡足类进行30 min不同升温幅度(△T)(0、4.0、8.0、12.0℃)下的余氯胁迫,观察桡足类在24h后的死亡率,用概率单位法计算其余氯半致死浓度(Median lethal concentration,LC50).结果表明各季节桡足类余氯LC50随△T增大而显著降低(P＜0.001),且.多数种类呈显著线性回归关系(P＜0.05).对于哲水蚤目桡足类,余氯LC50随其粒径增大而升高.同一种桡足类在相同△T下,随适应水温升高,余氯LC50显著降低(P＜0.01).亚热带海区夏季自然水温较高,冷却系统轻微的升温即可加剧余氯对其的毒性.若以LC50×0.5来确定桡足类余氯安全浓度,则春、秋、冬季暴露时间≤30 min、△T≤12.0℃时,其余氯安全浓度分别为0.21-0.86 mg/L、0.26-0.86 mg/L、0.32-4.55 mg/L;夏季暴露时间≤30 min、△T≤8.0℃时,其余氯安全浓度为0.15-0.41 mg/L.当前电厂加氯浓度偏高对冷却水中桡足类造成较大影响,但排出水中余氯对其影响不大.基于生态安全考虑,根据对余氯较敏感的小型桡足类在不同季节下的余氯安全浓度,建议亚热带滨海电厂夏季余氯排放浓度不超过0.15 mg/L,其余季节不超过0.20 mg/L.     

壳聚糖/海藻酸钠微囊在中药提取物缓释制剂中的应用

壳聚糖/海藻酸钠生物微胶囊作为一个优良的缓释给药系统,具有良好的生物相容性和机械强度,原料易得、价格便宜,制备工艺简单且可工业化生产而倍受国内外从事生物微胶囊研究的学者关注.本文综述了壳聚糖和海藻酸钠的理化性质、生物微胶囊制备原理和方法以及其在中药提取物缓释制剂中的应用.     

细胞周期因子与植物根系发育

植物根系的发育是一个非常复杂且被精确调控的过程,受到多种信号的调控,其中对细胞分裂水平调控的研究已经成为细胞生物学研究的热点之一.文章介绍了植物细胞周期因子和植物根系发育相关的细胞周期调控机制以及根系细胞周期激素调节的研究进展.