共查询到20条相似文献，搜索用时 437 毫秒
1.
目的观察C57小鼠视感光细胞的发育及微细结构,为应用C57小鼠提供实验依据,对了解人类视网膜感光细胞的发育提供参考和帮助。方法将出生后第3、7、14、21、28d的C57小鼠及成鼠采用4%多聚甲醛灌注固定后,取眼球,冰冻切片,应用opsin单克隆抗体免疫组织化学法检测感光细胞的发育。结果免疫组织化学法显示：C57小鼠出生第3d,视网膜尚未完全分层,染色阴性,未见成熟感光细胞;出生第7d,有少量细胞染色阳性,可见少量的感光细胞;出生第14、21、28d及成鼠染色阳性的感光细胞逐渐增多,视网膜分层达到10层。结论 C57小鼠视网膜感光细胞在出生后开始发育,至第7d可见阳性细胞,第14d视网膜层数及感光细胞基本和成年鼠一致,而后逐渐达到成熟。 相似文献
2.
误区一:误认为变形虫的分裂生殖是无丝分裂。其实,变形虫分裂过程中有核膜解体、纺锤体和染色体形成等过程,是典型的有丝分裂。误区二:误认为试管婴儿是从试管中培养出来的婴儿。其实,试管婴儿是体外受精和胚胎移植的产物,即在体外的一定培养液中让精子与卵细胞结合为受精卵,受精卵进行分裂,发育成一个多细胞胚,再将这个胚移植到母体培养,最终发育为成熟的胎儿。误区三:误认为动物都具有线粒体。其实,蛔虫、绦虫等体内寄生虫不含线粒体,因为我们 相似文献
3.
本实验以金鱼幼胚为材料,研究60Co-γ辐射对金鱼幼胚产生的致死致畸效应.分别在金鱼受精卵发育至4～8细胞期,多细胞期,囊胚早期进行辐射.通过对致死率和畸形率的分析发现:(1)其诱变剂量一定要小于临界值;(2)在金鱼幼胚发育过程中,诱变时期越早,损伤越小. 相似文献
4.
采用体视镜,相差显微镜和摄像机等器材观察萼花臂尾轮虫非多精卵的发育时间、形态和结构的变化。研究结果表明,轮虫的生长周期受温度影响较大,非受精卵的胚胎发育可分为两大阶段十一小阶段,发育时间为7～11小时。胚后发育分为两大阶段八小阶段,发育时间为27—42小时。轮虫非受精卵剥离母体后可以自行发育,母体对其发育有一定影响。 相似文献
5.
目的:探索一种高效、稳定的小鼠原代肝细胞分离方法,并延长其体外培养的时间。方法:取成年雄性C57BL/6小鼠,以含双抗的D-Hanks灌流液经肝门静脉充分灌注肝脏,然后以0.2 mg/mL的Ⅳ型胶原酶灌注消化,接着过滤、离心、洗涤,获得小鼠原代肝细胞。通过台盼蓝染色检验小鼠原代肝细胞活率,利用倒置显微镜观察肝细胞的形态变化,糖原染色鉴定细胞纯度,添加ITS-X和HGF细胞因子延长小鼠原代肝细胞的体外培养时间。结果:平均每只成年小鼠肝脏可提取获得原代肝细胞约2×107个,台盼蓝染色显示细胞活率均超过95%,糖原染色结果表明此方法获得的原代肝细胞纯度高于95%,通过添加HGF和ITS-X两种细胞因子能够有效地延长肝细胞形态的体外维持时间。结论:本实验在原有小鼠原代肝细胞两步灌流分离法和培养的基础上,经过优化,成功建立了一种高效、稳定的小鼠原代肝细胞分离和培养方法,为肝脏的体外研究提供了技术保障。 相似文献
6.
1 试题一株纯黄粒玉米与一株纯白粒玉米相互授粉 ,比较这两个植株结出的种子的胚和胚乳细胞的基因型 ,其结果是 ( )。A .胚的基因型不相同 ,胚乳细胞的相同B .胚的基因型相同 ,胚乳细胞的不相同C .胚和胚乳细胞的基因型都相同D .胚和胚乳细胞的基因型都不相同2 解题思路(1)玉米是雌雄 (单性花 )同株植物 ,雄花在植株顶端 ,雌花在植株中下部。所以纯合体的同一植株上产生的卵细胞、极核、花粉粒 (萌发成花粉管中的两个精子 )的基因组成都相同。(2 )根据第三章植物的个体发育知道 ,胚是由受精卵发育而来。胚乳是由受精极核发育而来 ,并… 相似文献
7.
8.
黄芩提取物对体外培养小鼠黑素瘤细胞黑素生成的调节作用 总被引：6，自引：0，他引：6
观察中药黄芩对B16F小鼠黑素瘤细胞增殖、黑素含量、酪氨酸酶活性的影响。采用体外培养的小鼠B16F黑素瘤细胞株,用MTT法测定细胞增殖情况;NaOH裂解法测定黑素合成;多巴氧化法测定酪氨酸酶活性。在浓度为0.01～1.0g·L-1时,黄芩可浓度依赖性促进B16F细胞增殖,酪氨酸酶活性和黑素含量,以1.0g·L-1为最佳。黄芩可促进细胞增殖,激活酪氨酸酶活性,提高黑素含量,从而为黄芩治疗白癜风的临床应用提供了实验依据。 相似文献
9.
目的:探讨氯氰菊酯染毒对老年C57BL/6小鼠脑皮层及血清中单胺类神经递质5-羟色胺(5-HT)、多巴胺(DA)和去甲肾上腺素(NE)的影响。方法:以20只健康老年C57BL/6小鼠为研究对象,雌雄各半,随机分成染毒组及对照组,其中染毒组给予氯氰菊酯100mg/kg(腹腔注射),每日1次,连续4日;对照组给予等体积生理盐水(腹腔注射)。染毒期间每日对小鼠的日常行为及体质量进行观察。染毒结束后,摘眼球取血、断头处死小鼠,分离血清及脑皮层,用ELISA法检测老年C57BL/6小鼠脑皮层及血清中5-HT、DA、NE的含量。结果:对照组C57BL/6小鼠一般状况较好,染毒组则精神萎靡,眼角有分泌物残留,身体有撕咬痕迹。染毒前后老年C57BL/6小鼠体质量变化无统计学差异(P0.05)。染毒组老年雄小鼠脑皮层及血清中5-HT、DA的含量低于对照组(P0.05);老年雌小鼠脑皮层及血清中5-HT、DA、NE的含量高于对照组(P0.05)。结论:氯氰菊酯急性染毒对老年C57BL/6雄小鼠及雌小鼠脑皮层及其血清中5-HT、DA、NE的含量产生一定影响。 相似文献
10.
黎婷 《商丘师范学院学报》2024,(3):56-59
哺乳动物卵巢中卵母细胞的生长伴随着卵泡发育,其中两个卵原因子,分别是生长分化因子9(growth differentiation factor 9,GDF9)和骨形态生成蛋白15(bone morphogenetic protein 15,BMP15),在关乎卵巢功能及生育能力的卵母细胞和颗粒细胞之间发挥了双向交互作用.而体外卵母细胞和颗粒细胞培养体系的完善,可以更好的研究二者之间的作用及影响.通过体外培养研究卵母细胞生长中颗粒细胞的作用、卵泡发育过程中卵母细胞的作用,发现颗粒细胞给卵母细胞提供营养成分和代谢产物,并通过旁分泌调节卵母细胞生长;而卵母细胞调节颗粒细胞增殖和分化,并通过分泌GDF9和BMP15诱导卵泡腔的形成,GDF9和BMP15的合成又受到颗粒细胞的调控. 相似文献
11.
12.
The performance of four groups of mice of two genotypes (DBA/2J and C57BL/6J) was observed in two avoidance situations. Two groups, one of each strain, were given a maximum of 30 conditioning trials in an active avoidance situation followed by a maximum of 30 trials in a passive avoidance situation. The other two groups, one of each strain, were given passive avoidance conditioning first, followed by active avoidance conditioning. Positive transfer of training was observed in both genotypes for mice that received active avoidance conditioning prior to passive avoidance conditioning. Little or no transfer was observed from passive to active avoidance in either strain. 相似文献
13.
Studies on characteristics of nanostructure of N-TiO2 thin films and photo-bactericidal action 总被引：1，自引：0，他引：1
Pseudomonas aeruginosa strain （AS 1.50） and Bacillus subtilis strain （AS 1.439） from Ming lake were decomposed by photocatalytic nanostructure N-TiO2 thin films in a photo-reactor under UV irradiation. The different thickness nanostructure N-TiO2 thin films coated on mesh grid were prepared by sol-gel method and immobilized at 500 ℃ （films A） or 350 ℃ （films B） for 1 h in a muffle furnace. The results showed that N-TiO2 thin film B （8.18 nm thickness, 2.760 nm height and 25.15 nm diameter） has more uniform granular nanostructure and thinner flat texture than N-TiO2 thin film A （12.17 nm thickness, 3.578 nm height and 27.50 nm diameter）. The bactericidal action of N-TiO2 thin film A and film B for Pseudomonas aeruginosa strain （AS 1.50） and Bacillus subtilis varniger strain （AS1.439） were investigated in this work. More than 95% of photocatalytic bactericidal efficiency for Pseudomonas aeruginosa strain （AS 1.50） and 75% for Bacillus subtilis strain （AS 1.439） were achieved by using N-TiO2 thin films-B for 70-80 rain of irradiation during the photo-bactericidal experimental process. The results indicated that the photo-induced bactericidal efficiency of N-TiO2 thin films probably depended on the characteristics of the films. 相似文献
14.
为了制备用于在斑马鱼中热休克全身表达目的基因的转基因载体,通过分子克隆的方法从P{hsFLP}86E/TM6B转基因果蝇的基因组中克隆出FLP.并同时对HSP-Wnt5A-EGFP载体进行改造,Wnt5A由FLP代替,并在FLP和EGFP编码区之间插入带有多克隆位点的IRES序列,获得pTol2-HSP-FLP-IRES-EGFP转基因表达载体.利用得到的转基因载体显微注射到斑马鱼单细胞期胚胎中进行表达分析,结果表明,经热激外源目的基因FLP和报告基因EGFP均能在斑马鱼中表达.pTol2-HSP-FLP-IRES-EGFP转基因表达载体的成功构建对于建立FLP/FRT重组系统的斑马鱼转基因实验模型具有重要意义. 相似文献
15.
Objective: The functional relationship between calculated alpha band spectral power and inter-/intra-hemispheric coherence during a three-level working memory task of patients with mild cognitive impairment (MCI) was investigated. Methods: Subjects included 35 MCI patients according to the DSM-IV criteria (mean age: 62.3, SD: 6.5) and 34 healthy controls (mean age: 57.4, SD: 4.0) were selected from the community at large. All subjects performed a simple calculation and recall task with three levels of working memory load while electroencephalograph (EEG) signal was recorded. The spectral EEG power was computed over alpha1 (8.0～10.0 Hz) and alpha2 (10.5～13.0 Hz) frequency bands and was compared between rest stage and working memory processing stage by two-way ANOVA. Post hoc testing analyzed the differences between each two levels of working memory load during task processing. The inter-hemisphere EEG coherence of frontal (F3-F4), central (C3-C4), parietal (P3-P4), temporal (T5-T6) as well as occipital (O1-O2) was compared between MCI patients and normal controls. The EEG signals from F3-C3, F4-C4, C3-P3, C4-P4, P3-O1, P4-O2, T5-C3, T6-C4, T5-P3 and T6-P4 electrode pairs resulted from the intra-hemispheric action for alpha1 and alpha2 frequency bands. Result: There was significantly higher EEG power from MCI patients than from normal controls both at rest and during working memory processing. Significant differences existed between rest condition and three-level working memory tasks (P<0.001). The inter-and intra-hemispheric coherence during working memory tasks showed a "drop to rise" tendency compared to that at rest condition. There was significantly higher coherence in MCI patients than in the controls. When task difficulties increased, the cortical connectivity of intra-hemispheric diminished while the inter-hemispheric connectivity dominantly maintained the cognitive processing in MCI patients. Conclusion: The results of the present study indicate that the alpha frequency band may be the characteristic band in distinguishing MCI patients from normal controls during working memory tasks. MCI patients exhibit greater inter-hemispheric connectivity than intra-hemispheric connectivity when memory demands increase. MCI patients mobilize a compensatory mechanism to maintain the processing effectiveness while the processing efficiency is reduced. 相似文献
16.
本文应用复合度的方法在f(x,y,z,u)无界的条件下证明了一般的四阶方程y=f(x,y,y′,y″) (*)在边界条件y(0)=A_1,y(1)=A_2,y″(0)=B_1,y″=B(_2或y(0))=A_1,y(1)=A_2,y″(0)=B_1,y(1)=B_2下解的存在性。 相似文献
17.
Rui CHEN Shao-hong LU Qun-bo TONG Di LOU Dong-yan SHI Bing-bing JIA Guo-ping HUANG Jin-fu WANG 《Journal of Zhejiang University. Science. B》2009,10(7)
The dense granule protein 4 (GRA4) is a granular protein from Toxoplasma gondii, and is a candidate for vaccination against this parasite. In this study, the plasmid pcDNA3. 1-GRA4 (pGRA4), encoding for the GRA4 antigen, was incorporated by the dehydration-rehydration method into liposomes composed of 16 mmol/L egg phosphatidylcholine (PC), 8 mmol/L dioleoyl phosphatidylethanolamine (DOPE), and 4 mmol/L 1,2-diodeoyl-3-(trimethylammonium) propane (DOTAP). C57BL/6 mice and BALB/c mice were immunized intramuscularly three times with liposome-encapsulated pGRA4 to determine whether DNA immunization could elicit a protective immune response to T. gondii. Enzyme-linked immunosorbent assay (ELISA) of sera from immunized mice showed that liposome-encapsulated pGRA4 generated high levels of IgG antibodies to GRA4. Production of primary interferon (IFN)-γ and interleukin (IL)-2 in GRA4-stimulated splenocytes from vaccinated mice suggested a modulated Th1-type response. 72.7% of C57BL/6 mice immunized with liposome-encapsulated pGRA4 survived the challenge with 80 tissue cysts of ME49 strain, whereas C57BL/6 mice immunized with pGRA4 had only a survival rate of 54.5%. When immunized BALB/c mice were intraperitoneally challenged with 103 tachyzoites of the highly virulent RH strain, the survival time of mice immunized with liposome-encapsulated pGRA4 was markedly longer than that of other groups. Our observations show that liposome-encapsulated pGRA4 enhanced the protective effect against infection of T. gondii. 相似文献
18.
Sucrose aversions were induced by lithium chloride toxicosis in 9-week-old male and female mice of the C57BL/6J and DBA/2J strains. Under conditions of ad-lib access to fluids which required a long interval between the sucrose and toxicosis, the conditioned aversions were relatively weak when compared with the sucrose consumption of saline-injected controls. The aversions extinguished rapidly within all groups. Contrary to earlier reports in rats, no sexual dimorphism in extinction rate was observed in this paradigm. When a fluid-deprivation schedule was implemented in the conditioning procedure to shorten the interval between taste experience and toxicosis, strong aversions were noted; yet relatively fast extinction under ad-lib conditions occurred in all groups except male DBA/2J mice. No sexual dimorphism was observed in mice of the C57BL/6J genotype, even when two pairings between sucrose and toxicosis were administered. 相似文献
19.
Burrows dug by house mice in laboratory burrow boxes were examined in two inbred strains (C57BL/6J and BALB/cJ) across five age groups and compared with burrows of wild trapped mice. Burrows of feral domestic mice were examined in an outdoor enclosure as well as in the laboratory. Results demonstrated that burrows differ between strains; highly active C57 mice tended to burrow more than did Balbs at all age ranges. Moreover, burrows became more complex with age in both strains. Differences among domestic, feral, and wild mice were minimal. Results are discussed in terms of possible genetic differences in activity and as evidence against the notions of degeneracy accompanying domestication. 相似文献
20.
Cun-jian MIAO Jin-yang ZHENG Xiao-zhe GAO Ze HUANG A-bin GUO Du-yi YE Li MA 《浙江大学学报(A卷英文版)》2013,14(1):31-37
Cold-stretched pressure vessels from austenitic stainless steels(ASS) are widely used for storage and transportation of liquefied gases,and have such advantages as thin wall and light weight.Fatigue is an important concern in these pressure vessels,which are subjected to alternative loads.Even though several codes and standards have guidelines on these pressure vessels,there are no relevant design methods on fatigue failure.To understand the fatigue properties of ASS 1.4301(equivalents include UNS S30400 and AISI 304) in solution-annealed(SA) and cold-stretched conditions(9% strain level) and the response of fatigue properties to cold stretching(CS),low-cycle fatigue(LCF) tests were performed at room temperature,with total strain amplitudes ranging from -.4% to -.8%.Martensite transformations were measured during the tests.Comparisons on cyclic stress response,cyclic stress-strain behavior,and fatigue life were carried out between SA and CS materials.Results show that CS reduces the initial hardening stage,but prolongs the softening period in the cyclic stress response.Martensite transformation helps form a stable regime and subsequent secondary hardening.The stresses of monotonic and cyclic stress-strain curves are improved by CS,which leads to a lower plastic strain and a much higher elastic strain.The fatigue resistance of the CS material is better than that of the SA material,which is approximately 1?03 to 2?04 cycles.The S-N curve of the ASME standard for ASS is compared with the fatigue data and is justified to be suitable for the fatigue design of cold-stretched pressure vessels.However,considering the CS material has a better fatigue resistance,the S-N curve will be more conservative.The present study would be helpful in making full use of the advantages of CS to develop a new S-N curve for fatigue design of cold-stretched pressure vessels. 相似文献