首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 109 毫秒
1.
离体诱导花粉细胞成愈伤组织要经历一段很长的过程。花粉细胞首先要去分化,脱离正常的配子体发育途径,转向孢子体发育方向发育,有报道,这一阶段的烟草花粉细胞质发生剧烈的改组,表明基因活动发生激烈的变化。另一方面,形态学观察表明,已经去分化的细胞经多次分裂形成多细胞团  相似文献   

2.
扁豆绒毡层发育的超微结构研究   总被引:1,自引:0,他引:1  
应用透射电镜对扁豆绒毡层发育过程进行了研究,主要结果如下:1)首次发现扁豆绒毡层在发育过程中,经历了二交胞质重组(第一次始于减数分裂末期Ⅱ,第二次始于小孢子发育早期),使绒毡层细胞的活动呈现3个高峰期(即小孢子母细胞减数分裂期、小孢子四分体期一小孢子早期、小孢子晚期-二胞花粉中期)。2绒毡层细胞的分泌作用有3种形式(渗透分泌、胞吐分泌和自溶)。3.首次观察到绒毡层细胞的内切向壁和径向壁经历了两个周  相似文献   

3.
水稻雄核发育途径及游离花粉粒培养的活体观察   总被引:1,自引:0,他引:1  
(1)在水稻雄核发育中,观察到 A—V、A—G、A—GV 和 B 途径,通常 B 途径占优势。在雄核发育早期,各种发育途径的花粉均有退化现象发生。(2)观察和统计表明,游离核型的多核花粉在发育过程中可转变为多细胞花粉,因而也是有发育前途的。(3)能够启动雄核发育的花粉通常是原生质稠密,在花粉群体中属中等大小(35—40μ)的花粉。多细胞花粉在突破花粉壁前。其细胞壁常常加厚,破壁时整个花粉有突然收缩的现象。(4)多细胞花粉内通常含有一些缓慢运动的小淀粉粒,它们可能积极参与了花粉雄核发育过程中的代谢活动。  相似文献   

4.
水稻花粉发育的分子机理   总被引:5,自引:0,他引:5  
水稻的小孢子母细胞在花粉囊中进行减数分裂产生小孢子,小孢子进一步发育成花粉粒。当花粉成熟时,花粉粒从花粉囊中释放出来进行受精。分子生物学的研究已经发现了一些参与这一过程的基因,包括控制花粉囊组织的分化、小孢子母细胞的减数分裂、小孢子的发育和花药的开裂等。本文旨在总结水稻花粉发育过程及其调控分子机制的研究进展。  相似文献   

5.
桑树花粉愈伤组织的诱导与花粉细胞学研究   总被引:1,自引:0,他引:1  
讨论影响桑树花粉愈伤组织诱导频率的问题 ,描述花粉细胞早期发育和愈伤组织的分化过程  相似文献   

6.
巾唇兰属是我国新记录属,近十余年来先后在我国南方发现了两种,包括在云南发现的新种——巾唇兰(Pennilabium yunnanense)。利用解剖镜和石蜡切片技术观察了巾唇兰具有分类学意义的花形态特征和花粉团发育的胚胎学特征,结果如下。成熟花的合蕊柱短,无蕊柱足;花粉块由2个球形花粉团、粘盘和粘盘柄组成。在花药发育早期,花药原基分化出一对侧生并列药室;在小孢子母细胞时期,每个小孢子囊在两个药室相邻的内花药壁处分化出一段不贯穿药室的不育隔膜组织。在花药发育过程中,该隔膜组织逐渐被吸收降解,到花粉成熟时形成2个开口朝内的孔裂花粉团。发育成熟的花药壁共有4层,发育类型为单子叶型,绒毡层为单核、腺质型。在小孢子母细胞进入减数分裂阶段,表皮细胞变窄出现了降解,中层和绒毡层细胞也逐渐被吸收和降解;花药成熟时,花药壁仅剩下残缺的表皮和纤维状加厚明显的药室内壁。小孢子母细胞通过同时型胞质减数分裂形成小孢子四分体,其排列方式主要为正四面体形和左右对称,成熟花粉为2细胞型。本文从形态发育角度澄清了巾唇兰花粉团特征的描述,讨论了其花粉团发育特征的分类学意义,为兰科花药发育多样性提供了新资料。  相似文献   

7.
试验用压片法对(普通小麦/长穗偃麦草)F1小孢子发生和雄配子体发育进行了细胞学观察.观察表明:1.(普通小麦/长穗偃麦草)F1花粉母细胞减数分裂过程中出现许多异常现象;在PMC M1出现较高频率的单价体和多价体;但是减数分裂过程能够完成,并且四分孢子的败育率较低。2.在雄配子体发育过程中可观察到具有多微核、体积不等的小孢子,并发现经过对称孢子有丝分裂产生的二胞花粉;在花粉发育的不同时期均可观察到花  相似文献   

8.
近年来,随着现代生物学技术及分子生物学技术在花粉生物学研究领域中广泛的应用,从而使花粉发育过程中一些关键问题及其有关分子机理的研究均获得了重要进展。目前已克隆了许多与花粉发育有关的基因,并鉴定了一些花粉发育的突变体。本文针对花粉发育过程中的细胞质改组;胼胝质壁、淀粉粒和细胞器的动态变化;绒毡层的发育;花粉发育特异基因;以及不对称分裂和细胞命运等几个生物学问题的研究进展作了简要综述,最后还提出了一些研究展望。  相似文献   

9.
花药培养中花粉去分化启动条件和药壁变化的初步研究   总被引:2,自引:0,他引:2  
研究了对花粉去分化启动的必需外源因素和花药培养过程中的药壁变化。结果如下:1.对于花药培养中的花粉去分化启动,至少要有糖的外源供应。2.花粉对等分裂的高峰出现在颤绒层消失之后,这暗示颤绒层的适时衰退可能有助于花粉的去分化启动。3.花药培养过程中,在药壁会出现糖和淀粉的积累,表明药壁还有若干合成活动。4.材料不同、培养基不同,药壁颤绒层衰退的迟早和药壁可溶性蛋白带谱的变化不同,这可能暗示材料差异和培养基对花药培养效率的影响,部分是通过影响药壁状况而实现的。  相似文献   

10.
红芒野稻-莲塘早不育系花粉败育过程的细胞形态学观察   总被引:1,自引:0,他引:1  
本文对于红芒野稻一莲塘早不育系选育过程中五个回交世代的花粉败育过程进行了观察。结果表明:花粉败育发生的时期从造孢组织开始直至单核花粉晚期。这些时期中都出现各种异常现象,使花粉发育不能进入双核期,最后败育。总的说来,五个回交世代中都可观察到导致花粉败育的各种异常现象;但花粉败育主要是在花粉发育的单核晚期。  相似文献   

11.
网上实验室克隆与鉴定食管癌相关基因ECRG—4   总被引:3,自引:0,他引:3  
利用生物信息学,探索网上克隆基因与鉴定基因的新方法。以因特网为平台,数据库为试验材料,各种软件为工具组成网上实验室,是人类基因组计划带来的实验技术革命。利用网上实验室以食管癌相关基因E-CRG-4的97bpEST为基础,成功克隆并鉴定了该基因。结果显示ECRG-4近似cDNA全长序列为772bp,其中含有一447bp的完整阅读框,编码148个氨基酸。氨基酸序列相似性分配表明ECRG-4与细胞膜上的免疫球蛋白超家族具有31%同源性。该基因定位于染色体2q141-14.3。组织分布表明ECRG-4须正常食管、膀胱组织中表达明显高于相应的癌组织。采用辐射杂交细胞系GeneBridge4RH嵌板作染色体定位进行初步验证,所得结果与网上克隆完全一致。研究提示,利用网上实验室克隆鉴定基因,是一种简便、精确的好方法。ECRG-4可能是一个在细胞癌变过程中具有非常重要意义的基因。  相似文献   

12.
A major advantage of microfluidic devices is the ability to manipulate small sample volumes, thus reducing reagent waste and preserving precious sample. However, to achieve robust sample manipulation it is necessary to address device integration with the macroscale environment. To realize repeatable, sensitive particle separation with microfluidic devices, this protocol presents a complete automated and integrated microfluidic platform that enables precise processing of 0.15–1.5 ml samples using microfluidic devices. Important aspects of this system include modular device layout and robust fixtures resulting in reliable and flexible world to chip connections, and fully-automated fluid handling which accomplishes closed-loop sample collection, system cleaning and priming steps to ensure repeatable operation. Different microfluidic devices can be used interchangeably with this architecture. Here we incorporate an acoustofluidic device, detail its characterization, performance optimization, and demonstrate its use for size-separation of biological samples. By using real-time feedback during separation experiments, sample collection is optimized to conserve and concentrate sample. Although requiring the integration of multiple pieces of equipment, advantages of this architecture include the ability to process unknown samples with no additional system optimization, ease of device replacement, and precise, robust sample processing.  相似文献   

13.
Cell-based meat, also called ‘clean’, lab, synthetic or in vitro meat, has attracted much media interest recently. Consumer demand for cellular meat production derives principally from concerns over environment and animal welfare, while secondary considerations include consumer and public health aspects of animal production, and food security. The present limitations to cellular meat production include the identification of immortal cell lines, availability of cost-effective, bovine-serum-free growth medium for cell proliferation and maturation, scaffold materials for cell growth, scaling up to an industrial level, regulatory and labelling issues and at what stage mixing of myo-, adipo- and even fibrocytes can potentially occur. Consumer perceptions that cell-based meat production will result in improvements to animal welfare and the environment have been challenged, with the outcome needing to wait until the processes used in cell-based meat are close to a commercial reality. Challenges for cell-based meat products include the simulation of nutritional attributes, texture, flavour and mouthfeel of animal-derived meat products. There is some question over whether consumers will accept the technology, but likely there will be acceptance of cell-based meat products, in particular market segments. Currently, the cost of growth media, industry scale-up of specific components of the cell culture process, intellectual property sharing issues and regulatory hurdles mean that it will likely require an extended period for cellular meat to be consistently available in high-end restaurants and even longer to be available for the mass market. The progress in plant-based meat analogues is already well achieved, with products such as the ImpossibleTM Burger and other products already available. These developments may make the development of cellular meat products obsolete. But the challenges remain of mimicking not only the nutritional attributes, flavour, shape and structure of real meat, but also the changes in regulation and labelling.  相似文献   

14.
王桂萍   《微生物学通报》2003,30(6):87-88
目的是提供一种理想的微生物培养室使用的灭菌供暖供温干燥装置。该装置由炉体(5)和灭菌干燥系统,包括鼓风机(1)、吸气管(13)、进气管(2)、受热管(3)、出气管(4);供温系统,包括水锅(6)、水锅进气管(7)、出汽管(8)、控制阀(9);燃烧系统包括出烟筒(10)、灶门(11),4大部分组成。结构简单、实用。  相似文献   

15.
As malaria remains a major health problem worldwide, various diagnostic tests have been developed, including microscopy-based and rapid diagnostic tests. LabChip real-time PCR (LRP) is a small and portable device used to diagnose malaria using lab-on-a-chip technology. This study aimed to evaluate the diagnostic performance of LRP for detecting malaria parasites. Two hundred thirteen patients and 150 healthy individuals were enrolled from May 2009 to October 2015. A diagnostic detectability of LRP for malaria parasites was compared to that of conventional RT-PCR. Sensitivity of LRP for Plasmodium vivax, P. falciparum, P. malariae, and P. ovale was 95.5%, 96.0%, 100%, and 100%, respectively. Specificity of LRP for P. vivax, P. falciparum, P. malariae, and P. ovale was 100%, 99.3%, 100%, and 100%, respectively. Cohen’s Kappa coefficients between LRP and CFX96 for detecting P. vivax, P. falciparum, P. malariae, and P. ovale were 0.96, 0.98, 1.00, and 1.00, respectively. Significant difference was not observed between the results of LRP and conventional RT-PCR and microscopic examination. A time required to amplify DNAs using LRP and conventional RT-PCR was 27 min and 86 min, respectively. LRP amplified DNAs 2 times more fast than conventional RT-PCR due to the faster heat transfer. Therefore, LRP could be employed as a useful tool for detecting malaria parasites in clinical laboratories.  相似文献   

16.
条形码自助取单系统的临床应用   总被引:1,自引:0,他引:1  
目的:通过创建条形码自助取单系统,实现检验报告单发放的自动化、科学化和人性化管理,实现无纸化验室。方法:在检验信息管理系统与医院信息系统实现无缝连接的基础上,门诊患者在医生申请检验项目收费处确认收费后,由门诊抽血护士站采集标本时生成条形码和条形码取单凭证,患者用条形码取单凭证上的条形码在自动取单机上扫描打印所有检验报告单,住院患者由医生根据申请在医生工作站自行打印检验报告单。结果:条形码自助取单系统代替了传统人工分发检验报告单的繁琐、遗失和重复打印等问题,节省人力,使用方便。结论:利用条形码自助取单系统实现了检验报告单管理的自动化、规范化和实验室管理的科学化,杜绝了交叉污染,保护了病人隐私。  相似文献   

17.
The chemical composition inclusive amino acids (AAs) and the energy and protein value of three wheat, three maize and seven blend (mainly wheat) dried distillers grains and solubles (DDGS) were determined. The net energy for lactation (NEL) was derived from digestion coefficients obtained with sheep. The digestible protein in the intestines (DVE) and the degraded protein balance (OEB) were determined by nylon bag incubations in the rumen and the intestines of cannulated cows. Additional chemical parameters like acid-detergent insoluble CP (ADICP), protein solubility in water, in borate-phosphate buffer and in pepsin-HCl, in vitro digestibility (cellulase, protease, rumen fluid) and colour scores (L*, a*, b*) were evaluated as potential predictors of the energy and protein value. Compared to wheat DDGS (WDDGS), maize DDGS (MDDGS) had a higher NEL-value (8.49 v. 7.38 MJ/kg DM), a higher DVE-content (216 v. 198 g/kg DM) and a lower OEB-value (14 v. 66 g/kg DM). The higher energy value of MDDGS was mainly due to the higher crude fat (CFA) content (145 v. 76 g/kg DM) and also to better digestible cell-walls, whereas the higher protein value was mainly due to the higher percentage of rumen bypass protein (RBP: 69.8 v. 55.6%). The NEL-value of blend DDGS (BDDGS) was in between that of the pure DDGS-types, whereas its DVE-value was similar to MDDGS. Although lower in CP and total AAs, MDDGS provided a similar amount of essential AAs as the other DDGS-types. Lysine content was most reduced in the production of WDDGS and cysteine in MDDGS. Fat content explained 68.6% of the variation in NEL, with hemicellulose and crude ash as extra explaining variables. The best predictor for RBP as well as for OEB was the protein solubility in pepsin-HCl (R2=77.3% and 83.5%). Intestinal digestibility of RBP could best be predicted by ADF (R3=73.6%) and the combination of CFA and NDF could explain 60.2% of the variation in the content of absorbable microbial protein. The availability of AAs could accurately be predicted from the rumen bypass and intestinal digestibility of CP.  相似文献   

18.
The microenvironment plays a major role in conferring chemoresistance to cancer cells. In order to better inform clinical response to chemoresistance, preclinical models that recapitulate its hallmark features are needed to enable screening for resistance‐specific therapeutic targets. A novel platform for seeding cancer cells in 3D hydrogels is presented utilizing derivatives of chitosan and alginate that, critically, is amenable to high throughput screening: cell seeding in hydrogels, media changes, dosing of anticancer compounds, and cell viability assays are all automated using a standard and commercially available liquid handling robot. Culture in these hydrogels elicits resistance in ovarian, lung, and prostate cancer cells to treatment by doxorubicin and paclitaxel. In correlation, proteomics analysis of SKOV3 cells cultured in 3D reveals enrichment of proteins associated with extreme drug resistance including HMOX1 and ALDH2. Subsequently, therapeutic antibodies targeted to tumor‐associated antigens upregulated in 3D cultures are shown to have higher efficacy compared to 2D cultures. Collectively, this automated 3D cell culture platform provides a powerful tool with utility in identification of drugs that may overcome chemoresistance.  相似文献   

19.
根据实验动物环境及设施国家标准(GB14925-2010)规定,结合公司的土建基础,综合考虑动物实验的要求,工程设计合理,施工规范。设施的各项指标均符合国家的相关标准。目前该设施总体运行良好,以下就该设施建设过程中的一些体会进行归纳。  相似文献   

20.
生物芯片技术   总被引:5,自引:0,他引:5  
高威  吴庆余 《生命科学》2000,12(5):237-240
生物芯片技术近年来发展极为迅速。生物芯片这一概念出现在20世纪80年代初,90年代以来随着人类基因组计划研究的深入,生物芯片技术也得以飞速发展。本文将对生物芯片的概念、发展做一全面的叙述,并详细地介绍最新的生物芯片,如DNA芯片等的基本原理、分类、制备,以及生物芯片的发展动向和应用前景。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号