miR-145通过靶向吞噬和细胞活力蛋白1抑制乳腺癌细胞侵袭

吞噬和细胞活力蛋白1（engulfment and cell motility protein 1,ELMO1）可以促进多种癌细胞的侵袭和转移,但ELMO1的表达是否受miRNA的调控鲜有研究。本研究旨在探讨miR-145与ELMO1表达的相关性,以及miR-145通过结合ELMO1的mRNA对乳腺癌侵袭的影响。通过TargetScan (http://www.targetscan.org/)靶基因预测软件预测与ELMO1的3′UTR结合的miR-145。荧光素酶结果证实两者互补结合。Transwell侵袭结果显示,miR-145组和siELMO1+miR-145组MDA-231乳腺癌细胞穿膜数较对照组分别降低40%（P＜0.05）和79%（P＜0.05）。siELMO1+miR-145组和siELMO1组细胞穿膜数则无显著差异（P>0.05）。结果提示,miR-145通过与ELMO1的mRNA结合抑制细胞侵袭。qRT-PCR显示,低侵袭的MCF-7乳腺癌细胞miR-145的表达量较高侵袭的MDA-435细胞高80%（P＜0.05）,较MDA-231乳腺癌细胞高75%（P＜0.05）,即miR-145与癌细胞侵袭能力呈负相关。Western印迹结果表明,miR-145组ELMO1表达量低于阴性对照组,miR-145 抑制组ELMO1表达量高于抑制剂NC组（P＜0.05）,证明miR-145抑制ELMO1的表达。qRT-PCR显示,过表达miR-145后ELMO1 mRNA含量与对照组无显著差异（P>0.05）。结果提示,miR-145对ELMO1的调控作用通过抑制其翻译实现。F-肌动蛋白聚合实验表明,miR-145组和阴性对照组于20 s和60 s时F-肌动蛋白聚合结果存在明显区别（P＜0.05）。Western 印迹结果表明,miR-145组活化的Rac1表达量较阴性对照组降低60%（P<0.05）,抑制剂NC组活化的Rac1较miR-145 抑制组降低55%（P<0.05）;miR-145组磷酸化的整合素β1较对照组于15 min时降低42%（P<0.05）,于30 min时降低31%（P<0.05）。由此得出的miR-145过表达显著促进乳腺癌细胞F-肌动蛋白聚合、Rac1活化和整合素β1磷酸化结论。综上所述,miR-145通过靶向ELMO1的 mRNA抑制ELMO1翻译,从而抑制乳腺癌的侵袭。     

Studies on fast and slow growing Rhizobium spp. nodulating Cqjanus cajan and Cicer arietinum

Fast and slow growing Rhizobium spp. isolated from Cajanus cajan and Cicer arietinum were compared in terms of colony characteristics, utilisation of carbon sources, acid production, symbiotic effectiveness and nodulating competitiveness. Fast growing isolates from C. cajan and C. arietinum formed 3–6 mm diameter colonies on yeast-extract mannitol agar after 4 days and were unlike the slow growers which produced colonies of c. 1 mm diameter after 7–10 days at 28 °C. The fast growing Rhizobium spp. from C. cajan utilised a wider range of carbon sources than the slow growing isolates from this host. Fast and slow growing strains from C. arietinum were able to utilise most of the carbon sources tested suggesting that the slow growers possessed glycolytic pathways similar to those in other fast growing species of Rhizobium. In culture, slow growing isolates from C. cajan produced a near-neutral to alkaline reaction (pH 66·7-5) whereas the fast growers from this host and both fast and slow growing isolates from C. arietinum produced an acidic reaction (pH 4·4–5·6). These data are discussed in the context of Norris' (1965) evolutionary concept of the Leguminosae. Under glassshouse conditions, fast and slow growing strains isolated from C. cajan and C. arietinum were equally effective on their respective hosts. In competition with slow growing rhizobia, half of the fast growers formed more than 70% of the nodules on C. cajan grown in sand. In all but one instance similar results were obtained when plants were grown in soil. With C. arietinum grown in sand or soil, all fast growing isolates from this host formed more than 85% of the nodules in competition with slow growing strains.     

Conjugation in Kahlia sp. with Special Reference to Meiosis and Endomitosis

SYNOPSIS. During conjugation of Kahlia the micronuclei divide 3 times before synkaryon formation and 2 times thereafter. The 1st division is heterotypic, as in other ciliates, in that it is characterized by the parachute stage. Following this stage, 24 to 26 bivalents and 4 to 8 univalents appear in the micronuclear area. When the bivalents move to organize the metaphase plate, the univalents lag behind and fail to reach the equatorial region at the same time. Due to this irregular behavior of the univalents there is no distinct metaphase in the first meiotic division. A few meiotic irregularities including the breakdown of the spindle apparatus have been observed. During the breakdown of the spindle apparatus the chromosomes fuse into irregular bodies which resemble the chromosome aggregates observed during the somatic divisions. Generally 1, and rarely more, of the products of the 1st division enter the 2nd division. The spindles of this division are oriented parallel to the long axis of the cell, and 1 of the daughter nuclei reaches the partition membrane separating the conjugants. This nucleus alone undergoes the 3rd division, resulting in the formation of gametic nuclei. Reciprocal exchange and fusion of the gametic nuclei result in the synkaryon formation. The synkaryon divides twice in rapid succession resulting in 4 daughter nuclei; 1 of them degenerates and 2 condense and become functional micronuclei. The chromosomes of the remaining daughter nucleus resemble in size and number the bivalents of the 1st meiotic division. They become polytenic and then reproduce to give rise to the polyploid macronucleus. The development of the macronucleus has been traced from a single diploid set of chromosomes and no evidence has been found for the formation of genetic “subnuclei.” During the early stages of the development of the macronuclear anlage, somatic pairing forces keep the homologs together, while in the later stages these forces cease to exert influence. While these changes are in progress the old macronucleus; breaks up into small irregular polymorphic bodies which are scattered throughout in the cytoplasm. The exconjugants usually encyst and the cysts are not favorable for detailed cytologic study.     

SOME UPPER CARBONIFEROUS FUSULINIDS FROM THE VICINITY OF BEIYIN OBO,INNER MONGOLIA

The fusulinids dealt with in this paper were collected in 1955 by Mr.L.S.Wong of a field party sent by the Ministry of Geology in the vicinity of BeiyinObo,Inner Mongolia(formerly province Suiyuan).The fusulinid-bearing bedof this area was named by Mr.Wong the Lalaotu limestone.No data of stra-tigraphical sequence of this region are readily available.Since no informationof the fusulines in this region has been hitherto known,the present discoveryaffords therefore some interest.     

有关赤眼蜂种鉴别的商榷

Quednan,W.在1956、1960年连续发表文章,提出用生物学特性的标准来辨别赤眼蜂种或生态型,是具有一定科学意义的,但忽视雄外生殖器的构造。石井悌(Ishii,T.,1941)曾建议根据雄虫外生殖器的构造来区别几种赤眼蜂,并成立两个新种,即Trichogramma chilonis与T.jezoensis。因为制片的关系,雄外生殖器构造部分看不清楚,故他所绘的图是不甚完善的;作者现改进了制片方法,使赤眼蜂雄外生殖器内部构造,在显微镜检视下较为明显,特为补充,重行描述,并取北京地区玉米螟卵赤眼蜂(T.chilonis)与桃捲叶蛾卵赤眼蜂(T.minutum)作为典型,以资比较。同时发现这两种赤眼蜂的前翅毛列与稻螟赤眼蜂(T.japonicum)有显著的差异,特别是第6条纵毛行与第8条横毛行汇合处,前者有缺口,呈倒“八”字形,后者无缺口,呈倒“人”字形(图2,A、B);而且稻螟赤眼蜂雄外生殖器内不具“针”,故不同意Quednau把T.chilonis并入T.japonicum种内作为“同物异名”,而应该维持石井悌的T.chilonis 仍为—个独立种。 作者1963,年在辽宁省丹东市郊区于柞蚕卵内发现一种食胎赤眼蜂(Trichogramma embryophagum (Hartig)),在国内为初次记载,确是产雌性孤雌生殖型。     

钾营养对水稻光合器功能的效应与谷粒产量的影响

水稻广陆矮四号和威优35盆栽试验的结果表明,施钾使叶绿体内基粒增多,Hill反应及光合磷酸化活力增强。分蘖末期在叶绿体反应液中添加KCl也可提高非环式光合磷酸化活力。适量施钾降低量子需要量可能与上述效应有关。钾使叶片超微结构改善:乳突大而多;硅化程度明显增加,故叶片更直立。叶水势及净光合率提高,两者呈直线正相关。灌桨期剑叶净光合率与谷粒产量呈直线正相关。     

大鼠杏仁核内注射八肽胆囊收缩素（CCK—8）拮抗吗啡镇痛的研究

大鼠双侧杏仁核内注射ＣＣＫ－８１ｎｇ（１μｌ）,能明显降低皮下注射４ｍｇ／ｋｇ吗啡产生的镇痛作用,并在０．１－１ｎｇ范围内呈量效关系。分别向双侧仁核注射ＣＣＫ－Ａ受体拮抗剂Ｄｅｖａｚｅｐｉｄｅ５０ｎｇ能部分翻转,２００ｎｇ则完全翻转ＣＣＫ－８的抗吗啡镇痛作用,１０ｎｇ无效;而ＣＣＫ－Ｂ受体拮抗剂Ｌ－３６５,２６０在５－８ｎｇ时即可完全番转ＣＣＫ－８的抗吗啡镇痛作用。杏仁核注射２００ｎｇ的Ｄｅｖａｚ     

基于细胞色素c的胞外电子传递过程

电活性微生物具有独特的胞外电子传递功能,在地球化学循环和环境污染修复中起着重要作用。细胞色素c在电活性微生物胞外电子传递过程中扮演了重要角色,不仅参与直接电子传递途径,还参与电子媒介介导的间接电子传递。其电子传递功能不仅对地球环境中铁、锰、碳等元素的循环具有重要作用,还应用于能源生产、废水处理、生物修复等众多领域,具有良好的应用潜力。本文以电活性微生物的2个模式菌属(希瓦氏菌属和地杆菌属)为例,综述了电活性微生物将电子由胞内转移至胞外的方式和途径,详细阐述了细胞色素c在该胞外电子传递过程中的重要作用,总结了细胞色素c介导的胞外电子传递过程所涉及的分析方法,并对微生物胞外电子传递未来的研究方向提出了展望。     

NO2胁迫下三角梅叶片形态解剖结构和最优光响应模型研究

植物的形态结构和光合作用能够反映植物对城市空气污染的响应特性。探究城市道路机动车尾气中的典型污染物NO₂气体,对植物叶片的生理光合响应特性。以二年生三角梅（Bougainvillea spectabilis）幼苗为对象,利用智能化人工熏气室模拟熏气（NO₂体积分数分别为0 μL/L （自然空气）、4 μL/L,8 μL/L,记作CK、T1、T2）,观察NO₂胁迫后三角梅的叶片形态、微观结构和光合特征。结果表明：（1）通过叶片形态观察发现,与CK相比,低浓度T1组叶片变化不明显,随着NO₂气体胁迫浓度的增加,高浓度T2组叶片逐渐出现失水、叶表面有明显的水渍状或烧灼状黄色斑点。（2）通过叶片微观结构解剖发现,高浓度NO₂胁迫后气孔皱缩程度增加,气孔开度减小;叶绿体结构变形,尤其是类囊体结构疏松,膨胀等变化。（3）叶片光合特性分析发现,T1和T2组的NO₂胁迫导致光饱和点（LSP）和最大净光合速率（P_nmax）下降、光补偿点（LCP）增加,表观量子效率（AQE）和暗呼吸速率（Rd）在4种光响应模型中变化规律存在一定的差异性。（4）4种光响应模型中,CK组决定系数（R²）越高,均方根误差（RMSE）越低,精度最高,尤以叶子飘等机理模型为最优,拟合效果最好,其次是直角双曲线模型。研究结果表明三角梅可通过自身的形态变化、调整光合特征参数,较好地适应不同浓度的NO₂,尤其是高浓度急性胁迫下,该研究结果有助于促进不同道路绿地三角梅的推广应用,对探究三角梅的景观效益和生态效益,揭示其对环境异质性的适应机制具有重要意义。