BCL-3的研究进展

bcl-3基因最初发现于B细胞慢性淋巴细胞白血病（B-CLL）的一个亚型,并被认为是其分子特征。研究显示BCL-3蛋白含七个锚蛋白样重复序列,属于IκB家族蛋白,在NF-κB途径中有着重要的调控作用。此后的研究显示,BCL-3在血液肿瘤及实体肿瘤中均可见过度或失控表达,发挥着促进肿瘤形成的作用,而其正常水平的表达对于正常免疫反应的形成和防止过度的炎症反应也是极其重要的。同时BCL-3也可对促进肿瘤形成的基因进行调控。本文现就BCL-3在这些方面的研究进展作一综述。     

沙门菌、志贺菌、副溶血性弧菌多重PCR检测方法的研究

建立快速检测沙门菌、志贺菌和副溶血性弧菌的多重PCR方法[1-4].根据沙门菌hilA基因、志贺菌ipaH基因及副溶血性弧菌TDH基因设计特异性PCR引物[5-6],被检样品经4 h振荡培养后金属浴裂解制备DNA模板,使用全自动毛细管电泳核酸检测系统分析PCR扩增产物.在580、423和245 bp处分别出现预期的特异性DNA条带,且无非特异扩增条带出现.敏感性试验显示沙门菌在模拟标本中的检测灵敏度为101-2cfu/mL、志贺菌为101cfu/mL、副溶血性弧菌为102cfu/mL.该方法操作方便、分析时间短、特异性和灵敏度高,可用于公共卫生突发事件食源性病原菌的快速检测.     

幼年大鼠青霉素点燃后慢性认知功能缺陷的分子机制研究

在建立发育期大鼠青霉素点燃模型的基础上,探讨点燃后至成年期不同发育阶段空间学习记忆能力改变,以及对海马记忆分子钙/钙调蛋白依赖的蛋白激酶Ⅱα(CaMKⅡα)、突触可塑性相关基因3(PRG-3)、抗惊厥脑肠肽胆囊收缩素(CCK)、锌离子转运体1(ZnT-1)和3(ZnT-3)表达的远期影响．生后29天(P29) 的SD大鼠随机分为青霉素点燃模型组(RS组,n=39)及生理盐水对照组(NS组,n=21)．RS组隔日腹腔注射青霉素,按体重5.60×10⁶ U/kg,连续6次,NS组以同样方法腹腔注射生理盐水．于末次惊厥后1.5、3、6和12 h透射电镜观察海马凋亡及自噬,于末次惊厥后1 h进行脑电记录,于末次惊厥后24 h 原位末端标记凋亡法(TUNNEL)检测海马凋亡细胞．分别于P51～P56、P81～P84、 P92～P95 进行3次Morris水迷宫实验,检测大鼠的学习记忆能力．最后,采用Timm染色观察海马苔藓纤维发芽,实时定量RT-PCR测定海马CaMKⅡα、PRG-3、CCK、ZnT-1和ZnT-3的表达．结果如下：a．电镜显示末次惊厥后1.5～12 h可见大鼠海马本部神经元内溶酶体被激活,自噬小体形成,12 h自噬和凋亡同时存在;TUNNEL显示凋亡细胞明显增多(P < 0.05)．b．RS组末次惊厥后3～5 min脑电图记录显示额叶丛集放电,棘波和尖波阵发．c．Morris水迷宫实验显示,第1次测试各组逃避潜伏期均呈逐渐下降趋势,但RS组第5天潜伏期明显高于NS组,具有显著性差异(P < 0.05),RS组第2次水迷宫测试中第1天潜伏期明显高于NS组,具有统计学意义,第3次水迷宫第2天的潜伏期仍明显高于NS组,具有统计学意义．d．在Morris水迷宫搜寻策略分析中采用秩和检验,第1次水迷宫对照组在第4天和第5天成绩明显优于RS组,具有统计学意义(P < 0.01),第2次和第3次水迷宫中对照组3天成绩均明显优于RS组,具有统计学意义(P < 0.05)．e．Morris记忆实验显示：3次记忆测试平台象限路径与总路径之比,RS组3次记忆测试均明显低于NS组,有显著性差异(P < 0.05)．f．Timm染色显示,RS组海马齿状回内分子层和CA3区锥体细胞层可见明显异常增生苔藓纤维,对照组未见发芽．g．在实时定量RT-PCR试验中,方差分析显示RS组海马CaMKⅡα和ZnT-1表达明显低于NS组(P < 0.05),聚类分析和相关分析表明,NS组CaMKⅡα、PRG-3、CCK、ZnT-3这4个基因具有共聚特征,并且各个基因之间具有显著相关性,而RS组仅海马CaMKⅡα和ZnT-1具有明显的共聚现象且呈正相关．本研究表明,幼年大鼠青霉素点燃后不仅能够造成海马神经元早期损伤(包括自噬和凋亡增加),而且产生远期的学习和记忆功能损害,并可能与海马记忆分子CaMKⅡ及ZnT-1表达下调有关．     

基于目标种保护的生态廊道构建——以崇明岛为例

景观破碎化和适宜生境面积减少是生物多样性降低与物种灭绝的重要因素之一。生态廊道的构建为陆行野生动物扩大活动范围提供了空间途径,从而增加了物种基因交流的机会, 提高了种群的生存能力。上海市崇明岛是一个地理上孤立的冲积沙岛,随着岛上森林斑块的减少与破碎化,依赖林地生境生存的陆行动物个体与种群数量大大减少。本文以崇明岛为例,选择上海市一级保护动物刺猬作为目标种,在分析其生活习性和基质斑块空间分布特征的基础上,利用最小耗费模型和GIS手段,实现了生境斑块之间的最佳连接,建立了以目标动物保护为目的的生态廊道规划方案。     

铜对水培紫云英的毒性

研究了水培条件下不同铜水平（CK、5、10、15、20、25 μmol·L^-1）对豆科植物紫云英(Astragalus sinicus)根、茎、叶生长发育的影响。结果表明：5 μmol·L^-1铜对紫云英根、茎、叶和根瘤生长均有促进作用,地下部（根）、地上部（茎叶）生物量显著增加,株高增加,根瘤呈粉色、多为复瘤、聚生,单瘤比对照大;当铜水平达10 μmol·L^-1时,地下部根的生物量增加依然达到显著水平（P<0.05）,株高较对照增加,但地上部生物量与对照无显著差异,根伸长受抑制,根长显著缩短;当铜水平达15 μmol·L^-1时,紫云英植株开始表现受害症状,根色转褐,叶片转黄,根瘤着生数量、根和地上部干质量以及分枝数均显著减少（P<0.05）。当铜水平提高到20 mmol·L^-1以上时,紫云英株高显著变矮,根长、根鲜质量和干质量、分枝数、株高/根长、地上部鲜质量和干质量也均随着铜水平提高而显著减少或降低。通过光镜和投射电镜观察,发现紫云英污染叶变厚,其原因是叶片细胞膨大和栅栏组织增厚;叶片转黄与叶绿体遭破坏有关;根系部分皮层细胞死亡可能影响根系吸水和植株水分运输,导致植株含水率降低。     

游泳动物对长江口新生盐沼湿地潮沟生境的利用

利用长袋网(fyke net)采集了长江口新生盐沼湿地潮沟内的游泳动物,分析了该类盐沼湿地的鱼类栖息地利用。结果表明,3次调查共记录到游泳动物20种,其中鱼类15种,虾蟹类5种。生态类群主要以淡水性种类(10种)和河口性种类(6种)为主,洄游性种类(3种)和海洋性种类(1种)较少。从数量组成来看,游泳动物群落主要由安氏白虾(35.4%)、棕刺虾虎鱼(17.7%)、贝氏餐(17.7%)、长蛇鮈(9.2%)和日本沼虾(4.6%)等少数几个物种占优势。这些游泳动物大多为稚幼个体,表明长江口新生盐沼湿地是许多鱼类和甲壳动物的重要育幼场所。     

无偿献血者中隐匿性乙型肝炎病毒感染及表面抗原突变分析

采用多种免疫学检测和核酸检测相结合的方法调查了我国南方某城市无偿献血者中隐匿性乙型肝炎病毒(HBV)感染的存在情况。结果在9023例乙肝表面抗原(HBsAg)阴性的无偿献血者中,共发现17例HBV DNA阳性,隐匿性HBV感染者的发生率为0.19%(95%CI:0.11～0.30%)。序列分析显示其中6例在HBsAg"a"表位(aa124～aa147)存在不同程度氨基酸突变,突变发生率为42.9%(6/14,有3例未扩增出"a"表位片段序列),G145R突变是该地区隐匿性HBV携带者中发生频率最高的突变(4/6,66.7%)。隐匿性HBV感染者中基因型C的比例(10/17)显著高于HBsAg阳性的HBV感染者(0/15,P<0.01)。     

The preservation of liposomes by raffinose family oligosaccharides during drying is mediated by effects on fusion and lipid phase transitions

Raffinose family oligosaccharides (RFO) have been implicated as protective agents in the cellular dehydration tolerance, especially of many plant seeds. However, their efficacy in stabilizing membranes during dehydration has never been systematically investigated. We have analyzed the effects of sucrose, raffinose, stachyose, and verbascose on liposome stability during air-drying. With increasing degree of polymerization (DP), the RFO were progressively better able to stabilize liposomes against leakage of aqueous content and against membrane fusion after rehydration. Indeed, there was a very tight linear correlation between fusion and leakage for all RFO. These data indicate that increased protection of liposomes against leakage with increasing DP is due to better protection against fusion. This is in accord with the higher glass transition temperature of the longer chain oligosaccharides. Further evidence for the influence of glass transitions on membrane stability in the dry state was provided by experiments testing the temperature dependence of membrane fusion. During incubation at temperatures up to 95 degrees C for 2 h, fusion increased less with temperature in the presence of higher DP sugars. This indicates that RFO with a higher glass transition temperature are better able to protect dry membranes at elevated temperatures. In addition, Fourier-transform infrared (FTIR) spectroscopy showed a reduction of the gel to liquid-crystalline phase transition temperature of dry liposomes in the presence of all investigated sugars. However, the RFO became slightly less effective with increasing chain length, again pointing to a decisive role for preventing fusion. A direct interaction of the RFO with the lipids was indicated by a strong effect of the sugars on the phosphate asymmetric stretch region of the infrared spectrum.     

New method for surname studies of ancient patrilineal population structures, and possible application to improvement of Y-chromosome sampling

Several studies showed that surnames are good markers to infer patrilineal genetic structures of populations, both on regional and microregional scales. As a case study, the spatial patterns of the 9,929 most common surnames of the Netherlands were analyzed by a clustering method called self-organizing maps (SOMs). The resulting clusters grouped surnames with a similar geographic distribution and origin. The analysis was shown to be in agreement with already known features of Dutch surnames, such as 1) the geographic distribution of some well-known locative suffixes, 2) historical census data, 3) the distribution of foreign surnames, and 4) polyphyletic surnames. Thus, these results validate the SOM clustering of surnames, and allow for the generalization of the technique. This method can be applied as a new strategy for a better Y-chromosome sampling design in retrospective population genetics studies, since the idenfication of surnames with a defined geographic origin enables the selection of the living descendants of those families settled, centuries ago, in a given area. In other words, it becomes possible to virtually sample the population as it was when surnames started to be in use. We show that, in a given location, the descendants of those individuals who inhabited the area at the time of origin of surnames can be as low as approximately 20%. This finding suggests 1) the major role played by recent migrations that are likely to have distorted or even defaced ancient genetic patterns, and 2) that standard-designed samplings can hardly portray a reliable picture of the ancient Y-chromosome variability of European populations.     

Spontaneous and double-strand break-induced recombination,and gene conversion tract lengths,are differentially affected by overexpression of wild-type or ATPase-defective yeast Rad54

Rad54 plays key roles in homologous recombination (HR) and double-strand break (DSB) repair in yeast, along with Rad51, Rad52, Rad55 and Rad57. Rad54 belongs to the Swi2/Snf2 family of DNA-stimulated ATPases. Rad51 nucleoprotein filaments catalyze DNA strand exchange and Rad54 augments this activity of Rad51. Mutations in the Rad54 ATPase domain (ATPase^–) impair Rad54 function in vitro, sensitize yeast to killing by methylmethane sulfonate and reduce spontaneous gene conversion. We found that overexpression of ATPase^– Rad54 reduced spontaneous direct repeat gene conversion and increased both spontaneous direct repeat deletion and spontaneous allelic conversion. Overexpression of ATPase^– Rad54 decreased DSB-induced allelic conversion, but increased chromosome loss and DSB-dependent lethality. Thus, ATP hydrolysis by Rad54 contributes to genome stability by promoting high-fidelity DSB repair and suppressing spontaneous deletions. Overexpression of wild-type Rad54 did not alter DSB-induced HR levels, but conversion tract lengths were reduced. Interestingly, ATPase^– Rad54 decreased overall HR levels and increased tract lengths. These tract length changes provide new in vivo evidence that Rad54 functions in the post-synaptic phase during recombinational repair of DSBs.