共查询到19条相似文献,搜索用时 31 毫秒
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本文应用电子显微镜技术观察了正常钉螺及溴乙酰胺作用后的钉螺头足部软体组织及肝脏组织的超微结构。头足部软体组织有上皮层、上皮下层及肌层。上皮层有三种细胞:无纤毛上皮细胞、纤毛上皮细胞及含有大量粘性分泌颗粒的腺体细胞。上皮层细胞内含有丰富的线粒体、内质网及张力细丝。基底膜将上皮细胞与上皮下层分开,上皮下层有含色素颗粒的细胞。肌层为梭形细胞,核居中央,无横纹。溴乙酰胺作用24小时后,钉螺头足部的上皮细胞与肝脏腺管细胞肿胀,核增大;染色质凝集,线粒体肿胀、嵴断裂呈空泡状,粗面内质网变粗呈短管状,排列混乱,或呈同心圆指纹状排列。这些病变与生化代谢结合进行了讨论。 相似文献
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体外神经干细胞克隆球的超微结构-透射电镜观察 总被引:5,自引:0,他引:5
为观察培养的神经干细胞克隆球内部的超微结构特征,采用无血清培养技术,在体外进行小鼠纹状体神经干细胞克隆球的培养传代,经过免疫细胞化学鉴定后,对单一的神经干细胞克隆球进行固定,常规透射电镜观察。结果表明,神经干细胞可以在bFGF等生长因子存在的情况下,在无血清培养液内增殖生成悬浮状态的神经干细胞克隆球,这种克隆可被诱导生成神经细胞和神经胶质细胞,电镜下,神经干细胞克隆球内部细胞相互间可形成特化的膜性结构,细胞内可有小泡出现,部分细胞有凋亡的形态。 相似文献
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本研究主要采用透射电镜观察粉尘螨Dermatophagoides farinae (Hughes)生殖系统超微结构。粉尘螨雄性生殖系统是由精巢、 输精管、 附腺、 射精管、 交配器官及附属交配器官组成。精巢内可同时有精子发育各阶段的细胞。精子无核膜、 核染色质聚集成束、 线粒体缺乏典型的嵴、 胞质内有平行排列的电子致密薄片等为其特征性结构。雌性生殖系统由交合囊、 交合囊管、 储精囊、 囊导管、 卵巢、 输卵管、 子宫及产卵管构成。卵巢内可见含多个细胞核的中央细胞, 其周为卵母细胞等生殖细胞。该研究丰富了对粉尘螨生殖系统结构的认识。 相似文献
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应用透射电子显微镜对黄鳝(Monopterus albus)所谓退化性腺(即膀胱)的黏膜上皮进行了研究。根据细胞形态与超微结构的特征,在黄鳝膀胱上皮中识别出六类细胞:表层细胞、淋巴样细胞、多线粒体细胞、亮细胞、椭圆体丰富细胞和基层细胞,但未发现生殖细胞。这六类细胞均含较丰富的细胞器,其中椭圆体性质尚不明确。上皮细胞间存在着由紧密连接、桥粒以及镶嵌连接组成的连接复合体和一些散在的桥粒。结果还发现,收缩状态的黄鳝膀胱上皮细胞间具有明显的空隙、空腔;细胞内存在着数量不等的网孔,它们是长指状突起造成的隧道断面;黄鳝膀胱上皮具有典型的AUM斑、镶嵌连接和表层细胞离面的短指状突起。此外,作还论证了黄鳝右侧发达性腺是两条性腺的复合体以及它们与左侧的所谓退化性腺同体存在的问题。研究结果支持了作曾经提出的有关黄鳝所谓退化性腺是发达膀胱的论点。 相似文献
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小鼠植入前胚胎的发育过程中,核仁经历从简单到复杂、从致密结构到网状结构的变化。对核仁超微结构的观察有助于揭示早期胚胎发育过程中核仁结构的动态变化及其特定阶段的功能。但由于核仁结构微小,数目较少,并且在胚胎中只处于卵裂球细胞核的内部,难以定位,因而给核仁的超微结构观察带来很大的困难。本实验探索了透射电镜观察小鼠植入前胚胎核仁的方法:先用琼脂对小鼠胚胎进行预包埋,在经过常规的透射电镜样品制备流程后,将整个胚胎先切成半薄切片;经过甲苯胺蓝染色后,选取含核仁结构的切片进行重包埋;最后再对回收来的半薄切片进行超薄切片,醋酸铀染色后上电镜观察;最终成功获得小鼠胚胎植入前发育不同时期核仁清晰的透射电镜图像。 相似文献
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低浓度氯硝柳胺控释剂浸液对钉螺存活及繁殖影响的试验观察熊维楷,蔡德全,席金玉,卢永嵩,左士会四川省寄生虫病防治研究所成都610041本文报道在实验条件下钉螺接触低浓度氯硝柳胺控释剂(简称控释剂)浸出液和低剂量控释剂丸粒对其存活繁殖的影响。1方法和结果... 相似文献
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Conditions were established for routine cinemicrographic examination of sperm incorporation by living zona-free mouse eggs employing oil immersion objectives and Nomarski optics. Initial sperm attachment to the egg plasma membrane, which was reversible and appeared to require flagellar activity, involved localized areas of the head corresponding approximately to the position of the equatorial segment. Penetrating sperm lay flat on the egg and, during incorporation, appeared to sink into the egg cytoplasm, accompanied by short bursts of flagellar activity and subsequent rotation of the flagellum around its insertion point. Ensuing sperm head decondensation involved dissociation of individual particulate structures and a dramatic localized clearing in the egg cytoplasm. The normalcy of the penetration process and the potential applicability of this approach was attested to by the observations that polar body extrusion, male and female pronuclear formation, and migration through the egg cytoplasm in preparation for syngamy occurred in several sequences followed for extended time periods. 相似文献
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Summary Both frequency and morphology of the nutritive eggs in the snails Crepidula dilatata and Nucella crassilabrum were analyzed. In both species, nutritive eggs constitute over 90% of the eggs deposited in each capsule. Marked differences in nutritive eggs exist between these species with respect to morphological and cytological characteristics. Nutritive eggs of C. dilatata remain uncleaved and in their cytological characteristics resemble oocytes whose development becomes arrested at the stage of germinal vesicle. Although the eggs of this snail are dimorphic in size, such dimorphism is not correlated with the fate of these cells. Nutritive eggs of N. crassilabrum typically abort their development at the stage of zygote cleavage divisions and anarchic cleavage occurs only in a small fraction of them (X = 5–6%). The nature of these food eggs is discussed. Our findings suggest that, at least in C. dilatata, the mechanisms of nutritive egg formation reside in properties of the oocyte. 相似文献
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本文应用氚-烟酰苯胺标记湖北钉螺,示踪观察不同时间烟酰苯胺进入螺体组织和脏器内的分布和进入途径。结果显示,钉螺接触药物从22分钟开始检测出组织、脏器内氚含量,以后逐渐增高,至1440分钟达最高峰;合计不同时间各组织和脏器中药物含量由高至低排列次序为外套膜、胃肠、肝脏、肠内粪梗、睾丸、卵巢、鳃、神经节、心脏;转换氚含量为烟酰苯胺剂量,证实了烟酰苯胺杀螺的低用量与高效性;由单位重量组织和脏器中药物含量排位,反映出药物在螺体分布动态变化,以及药物通过消化系统、呼吸系统、外套膜表皮三条途径进入。 相似文献
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The present study was undertaken to determine conditions for parthenogenetic activation of mouse and rabbit eggs by electric stimulation in vitro. The cumulus-free eggs were submitted to square direct current pulses at output voltage of 1.0 to 2.5 kV/cm for 25 to 200 μsec. The best conditions for the activation of mouse eggs were 1.5 kV/cm for 100 μsec, in which 78% of eggs were activated, 32% of which developed to blastocysts in vitro. When the nonelectric solution (0.3M mannitol) was used for electric stimulation, the activation rate was quite low (16%). Optimal conditions for activation of rabbit eggs were 1.5 kV/cm for 200 μsec, in which 77% of eggs were activated, 25% of which developed to blastocysts. Unlike mouse eggs, rabbit eggs frequently had three pronuclei after electric stimulation. It is clearly shown that electric stimulus can induce parthenogenetic activation of the mouse and rabbit eggs in vitro. 相似文献
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Summary We demonstrate here the existence of a range of size-independent reproductive tactics in teleostean fish involving the allocation of a size-dependent reproductive effort between fecundity and egg size. Despite considerable evidence that larger eggs and the larvae hatching from them are more likely to survive than smaller ones, we found no evidence of evolutionary trends towards greater egg sizes. Fish with pelagic eggs tend to spawn many, and therefore small, eggs, whereas demersal spawners tend to produce large, and therefore few, eggs. Maximizing egg number should increase the number of eggs hatching in suitable locations in the patchy pelagic environment and, hence, increase the reproductive success of pelagic spawners. On the other hand, the reproductive success of demersal spawners, which reduce the variance in growing conditions experienced by the off spring, should be more dependent on the survival of the individual larvae, which increases as egg size increases. 相似文献