亚硒酸钠对人胃腺癌细胞中c-Ha-ras和-cerbB2癌基因及其蛋白的影响

应用细胞原位杂交和免疫胶体金技术，观察亚硒酸钠处理人胃腺癌细胞前后，ｃ－Ｈａ－ｒａｓ和－ｃｅｒｂＢ２癌基因转录水平及其产物Ｐ２１和Ｐ１８５癌蛋白表达的变化，结果表明，两种癌基因在ＭＧｃｘ８０－３细胞中活跃表达，亚硒酸钠能抑制ｃ－Ｈａ－ｒａｓ和－ｃｅｒｂＢ２癌基因的转录水平及Ｐ２１和Ｐ１８５癌蛋白的表达，这对于诱导胃癌细胞向正常细胞方向逆转具有重要意义

亚硒酸钠对人胃腺癌细胞生长和超微结构的影响

MGc80-3细胞经3×10~(-6)mol/l亚硒酸钠处理后,细胞生长曲线与分裂指数显著下降,倍增时间延长、生长抑制率达64.8％、~2H-TdR放射自显影观察表明标记指数从44.4％下降至7.1％,核内几乎见不到银粒,显示胃癌细胞DNA合成受到有效抑制,电镜下可见亚硒酸钠处理的细胞,核质比例下降,核形规则,核仁体积缩小,数量减少,核内异染色质减少,常染色质增多,细胞质内高尔基复合体发达,线位体结构典型,粗糙型内质网丰富,细胞表面微绒毛减少等显著变化,结果证实亚硒酸钠能改变MGc80-3细胞的恶性表型特征,具有诱导胃癌细胞分化的显著作用

胃癌细胞中硒分布、含量与谷胱甘肽过氧化物酶的关系

通过电镜放射自显影,原子吸收光谱法分析硒在胃癌细胞中的分布和含量,光谱法测定细胞中谷胱甘肽过氧化物酶活性,结果表明亚硒酸钠主要作用于胃癌细胞的线粒体和细胞核,对线粒体DNA,细胞核DNA的复制和基因表达均有一定的作用,在亚硒酸钠处理的胃癌细胞中,随着硒含量的提高,谷胱甘肽过氧化物酶活性也提高,从而阻止了线粒体中的脂质过氧化反应,使线粒体结构与功能恢复正常

亚硒酸钠对人胃腺癌细胞线粒体结构与功能的影响

3×10~(-4)mol/l亚硒酸钠处理人胃腺癌MGc80-3细胞后,线粒体结构发生了明显变化:线粒体结构典型,多呈短棒状,大小较一致,分布均匀,线粒体嵴明显增多,密度和长度增大,排列方向较一致,线粒体空泡化和嵴扩张现象显著减少,表现出与人正常胃粘膜原代培养细胞线粒体基本相似的特征,进一步分析与线粒体相关的细胞色素氧化酶活性,发现亚硒酸钠可以显著提高该酶活性,由此表明,亚硒酸钠通过改变胃癌细胞线粒体的恶性结构,使线粒体功能恢复正常,调节了细胞代谢机能,从而诱导胃癌细胞向正常细胞方向分化

AN ULTRASTRUCTURAL STUDY ON CELLS WITHIN MERISTEMATIC REGIONS IN CALLUS CULTURES of STEVIA REBAUDIANA ON DIFFERENTIATING MEDIUM

对甜菊（STEVIArEbAudIAnA）愈伤组织中尚未发生器官分化的分生细胞团进行了超微结构研究.结果表明，在器官分化条件下，愈伤组织中形成的分生区域的细胞体积小，细胞核大，核仁明显，且具核仁泡，部分细胞核中含有核内含物.大量小液泡分布在细胞的边周或散布于整个细胞中.液泡中通常含有陷入的细胞质成分和膜状物.部分液泡的形成与内质网膨大有密切关系.同时也观察到由内质网形成的多圈膜和双层膜包围细胞质成分的同心环结构.高尔基体及其小泡丰富，有时聚集分布在细胞某一区域.核糖体密集，有的聚集成多聚核糖体.因此，愈伤组织中分生区的细胞与分生组织中的液泡化和分裂的细胞类似.分生区细胞的另一明显特征是出现质膜内陷.推测这些超微结构特征可能反映了甜菊愈伤组织器官分化前的某些形态变化。An ultrastructural study of the cellular events during the early stages of organization in the zones of localized active cell division was made in the callus cultures of Stevia rebaudiana.The callus cultures undergo marked changes in structure when transFerred to a diFFerentiating medium containing benzyladenine,which is known to induce organ diFFerentiation in this system.Cells within meristematic regions Formed in the callus have small size,large nucleus,some of which contain intranuclear inclusions,with both prominent and vacuolated nucleolus and numerous small vacuoles distributed around the periphery of the cell or dispersed throughout the cytoplasm.In many cases,the presence of cytoplasmic and membranous protrusions was observed in the vacuoles,some of which is in close association with dilated endoplasmic reticulum.Multiple and double membrane-bound concentric structures derived From endoplasmic reticulum were often observed as well.Dictyosomes and their associated vesicles are common,sometimes appear in groups.The cytooplasm contains ribosomes,which are occasionally seen as clusters of polysomes.ThereFore,cells within meristematic regions are similar to the vacuolating and dividing cells of meristem.Another distinctive Feature of these cells is the appearance of plasmalemma invaginations.They increase the surFace area of the plasmalemma of the cell and may Facilatate the absorption of the digested contents of neighboring crushed callus cells.It is concluded that these ultrastructural events reFlect some morphological changes which precede organ diFFerentiation in the cultured callus of Stevia rebaudiana

视黄酸对BEL-7402细胞酶活性及基因表达的影响

人肝癌ＢＥＬ－７４０２细胞分别以５μｍｏｌ／Ｌ、２０μｍｏｌ／Ｌ和５０μｍｏｌ／Ｌ的视黄酸（ＲＡ）处理后，细胞生长明显受抑，平均细胞群体倍增时间延长，并呈ＲＡ浓度及处理时间依赖性关系．经２０μｍｏｌ／ＬＲＡ处理的细胞中，ｒ－谷氨酰转肽酶（ｒ－ＧＴ）活性自给药后第２天即持续下降，至第６天降至４４．５％，而酪氨酸－α－酮戊二酸转氨酶（ＴＡＴ）活性则持续增高，至第６天较对照组高近１倍．经２０μｍｏｌ／ＬＲＡ处理５ｄ后，ＲＮＡ斑点杂交分析表明ｐ５３基因转录加强，而Ｎ－ｒａｓ基因表达下降，提示该两基因的表达变化可能在ＢＥＬ－７４０２细胞的生长抑制及逆转过程中起重要作用，有关机制尚待深入研究

银染巢式RT-PCR检测胃癌淋巴结微转移方法

以Ｋｅｒａｔｉｎ１９ｃＤＮＡ的套式引物建立了巢式ＲＴ－ＰＣＲ扩增Ｋｅｒａｔｉｎ１９ｍＲＮＡ的体系及ＰＡＧＥ－银染检测扩增产物的方法；对扩增体系进行优化后，分析了扩增特异性及检测敏感性，并对临床样品作了初步检测．结果表明：该扩增体系具有较好的特异性，其敏感性可达１０－６μｇＲＮＡ，即可从１０５个淋巴细胞中检出１个胃癌细胞；对临床样品检测的结果与病理检查结果相符．显示该法具有较好的可靠性

A Study on Embryo Membrane of Horseshoe Crab (Tachypleus tridentatus) Using Scanning Microscopy

中国鲎的胚胎主要有三层被膜 :卵壳膜、内卵膜和胚护膜 .它们对胚胎发育的正常进行至关重要 .扫描电镜研究结果显示 ,卵壳膜被覆于成熟的卵子和 S19之前的胚胎表面 ,厚约 80 .0 μm,是中国鲎卵子和早期胚胎的主要保护性结构 ;内卵膜在晚期囊胚和原肠胚期形成 ,至胚胎发育完成时蜕去 ,厚约 18.0～ 32 .0 μm,外表面布满大小不等、结构相似的凸起的结构单位 ,内表面衬有直径约0 .1μm,互联呈网的纤维 ,内卵膜和在 S19时才完全形成的胚护膜是晚期胚胎的主要保护性结构 .Embryo membranes are very important for developing horseshoe crab embryo. In the present study, the embryo membrane changes of horseshoe crab(Tachypleus tridentatus)with the development of embryo were observed. Chorion, which formed in the egg development, was covered in the surface of embryo before S19 embryo and about 80.0 μm in thickness. The inner membrane shaped in later blastula and early gastrulae was 18.0~32.0 μm thick and became thinner and thinner with growth of embryo until it was discarded by first year instar. The outer surface of inner membrane was constituted by many similar protruding unites while the inner surface was covered by fibers which were 0.1 μm in diameter and connected each other. The embryo membrane appearing at last stage was the embryonic cuticle, formed in S11 to S19 stage and disappeared together with inner membrane when embryo development finished.国家自然科学基金!(38970 4 2 0 );; 福建省自然科学基金!(C90 0 4 4 );; 高等学校重点实验室访问学者基金!(99150 )资助项

CHLOROPLAST ULTRASTRUCTURE AND DEDIFFERENTIATION IN TISSUE CULTURES of STAEVIA REBAUDIANA BERTONI

含有叶绿体的甜菊（STEVIArEbAudIAnA）愈伤组织细胞转移至新鲜培养基后，导致光合片层的逐渐减少或消失，最后叶绿体脱分化形成原质体样的结构。超微结构观察表明，光合片层的减少或消失与降解及叶绿体分裂特别是不均等缢缩分裂而致基质组分和类囊体膜稀释有关。这一过程并不完全同步，一些质体含有少量正常的片展而另一些质体含有退化的片层甚至片展结构完全消失。细胞的一个明显特点是细胞器大多聚集在细胞核附近，细胞质增加并向细胞中央伸出细胞质丝。同时可观察到原质体。培养7d后，许多细胞呈分生状态，细胞质富含细胞器，充满了细胞的大部分空间。此时细胞中的质体大多呈原质体状态。在细胞生长的稳定期，质体内膜组织成基质基粒片层，同时质体核糖体增加。文中讨论了高度液泡化细胞脱分化与细胞中叶绿体脱分化的关系。Cells of Stevia rebaudiana callus tissue contain chloroplasts when cultured in a liquid medium in the light.TransFer of the callus into the Fresh culture medium results in the gradual decrease or disappearance of photosynthetic lamellae and the eventual dediFFerentiation of chloroplasts to Form proplastid-like structures.This decrease or disappearance of photosynthetic lamellae is Found to be correlated with the degradation of internal membranes, coupled With the diluting out of stroma constituents and thylakoid membranes due to chloroplast divisions, especially unequal constriction.The process is not completely synchronized so that some plastids still retain a Few intact lamellae while other plastids contain degenerating lamellae or have lost the lamellae completely.In addition, some plastids observed at this stage contain one to several starch grains although starch is very rarely Found in the inocula.A stricking Feature at this stage is the apparent grouping of organells in the vicinity of the nudeus.The cytoplasm has increared in quantity and crosses the cell in bridge-like extensions partially Filling in the cell center.At this stage, well deFined proplastids are recognized.AFter 7 days of continuous culture, many Cells appear meristematic in that the cytoplasm, rich in organelles, Fills most of the cell.The majority of the plastids Found in the cell at this stage are proplastids.They may be ptesent as budded dividing Forms or as oval spheroids.Their internal structure consists of randomly positioned single thylakoids resembling those of proplastids in intact development leaves.During the stationary phase of cell growth, the internal membranes of plastids are organized into stacked grana interconnected by stroma thylakoids, and at the same time the plastid ribosomes increase.A correlation was discussed between the dediFFerentiation of the highly vacuolate cells induced by the subculturing process and a dediFFerentiation of the chloroplasts with the cells