中亚滨藜盐囊泡对NaCl胁迫的响应

利用光学显微镜和扫描电镜研究了不同浓度NaCl处理下中亚滨藜(Atriplex centralasiatica lljin)盐囊泡的适应性结构.结果表明,单位面积内盐囊泡随盐浓度的升高而增多.盐囊泡的泡状细胞体积随NaCl浓度的升高而增大,NaCl处理使盐囊泡的形状发生了改变,多呈圆形或卵圆形.不同于对照中的肾形.但不同浓度的NaCl处理对中亚滨藜盐囊泡的发育过程没有明显的改变.     

盐胁迫下冰菜盐囊泡细胞的比较代谢组学分析

为了研究盐胁迫下冰菜(Mesembryanthemum crystallinum)盐囊泡中代谢物的变化,通过液相色谱串联质谱（LC-MS/MS）技术对对照以及盐处理下冰菜的盐囊泡中的代谢物进行了鉴定及分析,共在冰菜盐囊泡中确定了356个已知代谢物。对差异代谢物的筛选结果表明,有37种代谢物的含量在盐处理后的盐囊泡中发生了显著变化。基于KEGG数据库对差异代谢物进行的代谢通路富集分析表明,KEGG中定义的植物激素信号传导、玉米素生物合成及嘌呤代谢等6条生化途径存在显著扰动。以上结果显示,盐处理能造成冰菜盐囊泡中的代谢物发生显著变化。     

满江红内生菌外膜泡囊的电镜观察与超微结构分析

前人研究表明,自然界中独立生活或纯培养的细菌等原核微生物会分泌外膜泡囊,这些泡囊在多个生物学过程中有着重要的作用。本研究用扫描和透射电镜对水生植物满江红体内的共生蓝细菌和内生细菌(合称内生菌)产生的泡囊进行了观察和超微结构特征分析。结果显示,这些内生菌不仅在活跃的营养生长期,而且在有性繁殖阶段均会释放泡囊,甚至在濒临死亡时也会排出泡囊。根据这些外膜泡囊的超微结构特征,将之分成5种类型,即中透型、内膜型、单核型、多核型和多泡型。通过对泡囊产生过程中超微结构变化的分析,认为本研究材料的内生菌周质层中的肽聚糖参与外膜泡囊的生成与释放。这一结果对阐明原核生物泡囊的发生机制具有普遍意义。本研究还对电镜图像的判读进行了讨论,以避免由于样品前处理等人为干预产生的假象而导致误判。     

胞外ATP对胡杨细胞囊泡运输的影响

在植物中,胞外ATP(eATP)作为一种重要的信号分子,调控植物的生长、发育及逆境响应等多种生命活动。这些植物细胞的生命活动与囊泡运输密切相关,然而,eATP是否对植物细胞的囊泡运输具有调控作用尚不清楚。本文利用能够标记囊泡运输的荧光染料FM1-43研究了eATP对胡杨细胞囊泡运输的影响。FM1-43染色结果显示,50 mol/L eATP对胡杨细胞胞吞作用不明显,而高浓度的eATP(200、400 mol/L)则会抑制其胞吞作用,其抑制作用与eATP浓度呈正相关。高浓度的eATP(200、400 mol/L)同样抑制胡杨细胞胞吐作用。而不同浓度的ADP(50、200、400 mol/L)处理则对胡杨细胞囊泡运输无明显影响。这说明高浓度eATP对胡杨细胞囊泡运输的抑制作用不是源于eATP的水解产物,而是来自于其本身的信号作用。药理学实验发现,ATP受体抑制剂PPADS(100 mol/L)能抑制高浓度eATP对胡杨细胞囊泡运输的限制作用,说明eATP是通过嘌呤受体介导的信号通路调控囊泡运输过程。但值得注意的是,嘌呤受体的另一种抑制剂suramin(100 mol/L)却对eATP的抑制作用不明显,因为suramin处理胡杨细胞后eATP(200 mol/L)仍能抑制囊泡运输。这说明在胡杨细胞中某一类与P2X同源的受体介导了高浓度eATP对囊泡运输的抑制作用。综上,eATP作为信号分子可调控胡杨细胞的囊泡运输,并且高浓度eATP对胡杨细胞的囊泡运输具有负调控作用。      

水生植物在园林中的应用配置

水生植物由于其独特的生物学特性,在园林中应用日益受到重视.本文就水生植物的分类、应用配置、功能及前景等方面作了阐述,为水生植物在园林中的应用提供参考.     

如何进行麝鼠人工活体取香

麝鼠香是成年雄性麝鼠囊腺中的分泌物,其抗炎、耐缺氧、减慢心率、降低血压及负性肌力等作用与天然麝香相似,还具有降低心肌耗氧量和促生长的活性,应用前景非常广阔.     

不同温度下福氏志贺菌与其膜囊泡的比较蛋白质组学研究

【目的】对不同温度下福氏志贺菌(Shigella flexneri)及其分泌的膜囊泡进行比较蛋白质组学分析,为进一步理解福氏志贺菌膜囊泡的生物学活性奠定基础。【方法】采用差速离心和密度梯度离心方法,分别富集纯化37℃和30℃培养条件下的野生型福氏志贺菌2a 301株和相应的膜囊泡;借助二维纳升液相色谱-线性离子阱质谱联用系统,对制备得到的4种组分蛋白进行鸟枪蛋白质组学鉴定分析。【结果】37℃和30℃培养条件下,福氏志贺菌菌体蛋白和膜囊泡蛋白的鉴定总数分别为1 510、231、1 412、281,4种组分的共有蛋白数为156。生物信息学分析结果发现:膜囊泡中特异性富集了核糖体结构蛋白和膜起源蛋白,且37℃培养条件下的膜囊泡特异包被了大量三型分泌系统相关蛋白。【结论】运用比较蛋白质组学技术首次分析了不同温度下福氏志贺菌及其膜囊泡的蛋白质组变化,发现一些温度相关的膜囊泡特异包被蛋白,为深入研究膜囊泡的选择性包被奠定基础。     

脂质体的作用机理及在兽医上的应用

脂质体 (liposome)系指将药物包封于类脂质双分子层内而形成的微型泡囊 (vesicle) ,也有人称脂质体为类脂小球或液晶微囊。其结构类似生物膜 ,在机体内能生物降解 ,特别是脂质体作为药物载体以其选择性高、靶向性强从而具有减少药物剂量、降低毒性、减少副作用等特点。近年来 ,随着生物技术的迅猛发展以及反相蒸发法、研磨法、冻融法、超声波分散法、冷冻干燥法等脂质体制备工艺的逐步完善[1] ,脂质体的研究前景广阔。我国兽医上 ,脂质体技术的应用主要表现在以下几方面 :作为抗寄生虫药物载体 ;作为抗感染药物的载体 ;作为基因工程载体 ;作…     

重庆市主产药用植物丛枝菌根结构多样性研究

对重庆市主产的21科37属38种药用植物的根系作了菌根染色制片观察,结果表明:有30种植物形成了丛枝菌根,占观察样品的78.9%,有8种植物没有观察到丛枝菌根,占观察样品的21.1%;在药用植物的丛枝菌根中,观察到了典型的菌根结构,如丛枝、泡囊、孢子、分枝状吸收结构、附着胞、菌丝等.表明重庆药用植物的丛枝菌根结构具有多样性的特征.     

正交试验优选白藜芦醇纳米囊泡处方

目的:以合成的聚乙二醇化聚十六烷基氰基丙烯酸酯(PEG-PHDCA)作为囊材,优选白藜芦醇纳米囊泡处方工艺。方法:采用薄膜分散水化超声法制备白藜芦醇纳米囊泡,以胆固醇用量、投药量、PEG-PHDCA用量为考察因素,以白藜芦醇载药量和包封率的综合评分为评价指标,采用正交试验优选白藜芦醇纳米囊泡处方。结果:白藜芦醇纳米囊泡的最优处方为白藜芦醇投药量为15mg,胆固醇用量为10mg,PEG-PHDCA用量为20mg。结论:以PEG-PHDCA作为囊材,制备的白藜芦醇纳米囊泡处方合理,有一定的研究价值。     

Preferred microtubules for vesicle transport in lobster axons

The hypothesis that transported vesicles are preferentially associated with a subclass of microtubules has been tested in lobster axons. A cold block was used to collect moving vesicles in these axons; this treatment caused the vesicles to accumulate in files along some of the microtubules. Quantitative analysis of the number of vesicles associated with microtubule segments indicated that lobster axons have two distinct populations of microtubules--transport microtubules that are the preferred substrates for vesicle transport and architectural microtubules that contribute to axonal structure.     

The structures of COPI-coated vesicles reveal alternate coatomer conformations and interactions

Transport between compartments of eukaryotic cells is mediated by coated vesicles. The archetypal protein coats COPI, COPII, and clathrin are conserved from yeast to human. Structural studies of COPII and clathrin coats assembled in vitro without membranes suggest that coat components assemble regular cages with the same set of interactions between components. Detailed three-dimensional structures of coated membrane vesicles have not been obtained. Here, we solved the structures of individual COPI-coated membrane vesicles by cryoelectron tomography and subtomogram averaging of in vitro reconstituted budding reactions. The coat protein complex, coatomer, was observed to adopt alternative conformations to change the number of other coatomers with which it interacts and to form vesicles with variable sizes and shapes. This represents a fundamentally different basis for vesicle coat assembly.     

Experimental models of primitive cellular compartments: encapsulation, growth, and division

The clay montmorillonite is known to catalyze the polymerization of RNA from activated ribonucleotides. Here we report that montmorillonite accelerates the spontaneous conversion of fatty acid micelles into vesicles. Clay particles often become encapsulated in these vesicles, thus providing a pathway for the prebiotic encapsulation of catalytically active surfaces within membrane vesicles. In addition, RNA adsorbed to clay can be encapsulated within vesicles. Once formed, such vesicles can grow by incorporating fatty acid supplied as micelles and can divide without dilution of their contents by extrusion through small pores. These processes mediate vesicle replication through cycles of growth and division. The formation, growth, and division of the earliest cells may have occurred in response to similar interactions with mineral particles and inputs of material and energy.     

Intracellular accumulation of T-cell receptor complex molecules in a human T-cell line

This work was aimed at understanding the mechanisms of T-lymphocyte function by studying the cellular distribution and traffic of molecules of the T-cell receptor complex. The accumulation of specific molecules in intracytoplasmic vesicles is related to the activation of T lymphocytes. Some of these molecules include acid hydrolases, the transferrin receptor, and class I antigens of the major histocompatibility complex. Molecules of the T-cell receptor complex have now also been found in intracytoplasmic vesicles in a human T-cell line derived from a lymphoblastic leukemia. Such vesicles were tightly associated with the cytoplasmic microtubule network. One functional aspect of this association is a cellular pathway by which vesicles traveling to and from the cell surface converge in an area of the cells that is rich in processing enzymes.     

DNA-dependent synthesis of RNA is not implicated in growth response of chick comb to androgens

Local application of actinomycin D does not detectably modify growth response of the chick comb to androgens. The mode of action of androgens on chick comb (a connective-tissue organ) appears to differ from their action on epithelial-tissue organs such as seminal vesicles and prostate.     

Polymerized surfactant vesicles: novel membrane mimetic systems

Vesicles formed from dialkyl surfactants containing vinyl, methacrylate, diacetylene, isocyano, and styrene groups have been stabilized by polymerization across their bilayers of head groups. Polymerized vesicles have shelf lives of many months and controllable permeabilities and sizes. The kinetics of surfactant vesicle photopolymerzation have been determined, and the mechanism of photopolymerization has been discussed as a two-dimensional surface process. Polymerized surfactant vesicles concentrate reagents in their aqueous interiors, in bilayers, and in their inner or outer surfaces. This, in turn, leads to altered reaction rates and sites. Polymerized surfactant vesicles also provide a good media for the generation, in situ, of small, uniform, and efficient colloidal catalysts.     

培养过程中温度对猪卵母细胞发育的影响(脂滴部分)

猪成熟的卵母细胞在体外20℃和37℃的条件下,以M—199为培养基,以未培养的卵母细胞做对照,分别培养24和48小时,观察和分析不同温度下猪卵母细胞的发育以及超微结构的变化。结果表明,不同温度对细胞内脂滴的数量没有影响,对脂滴内容物的致密度无显著影响,但对脂滴大小有影响。与对照组比较,实验组的脂滴明显增大。在37℃培养时,脂滴的大小与时间呈正比,20℃时,则先增大后缩小。形态上的差别:20℃培养时一些细胞的部分脂滴出现相变现象,未见脂滴的外排;37℃时脂滴的变化不同。猪卵母细胞不耐低温,可能由于猪卵母细胞含有大量脂类,低温时由液晶态的脂类变成晶态,使细胞失去正常功能,甚至死亡。     

云南烟草丛枝症病害研究 II细胞的超微病变

超薄切片观察云南烟草丛枝症病害的病叶组织,并抽提试验材料的总核酸电泳检测,结果表明：病组织中检测到与烟草丛枝症病害相关的低分子量ＲＮＡ,切片中未观察到病毒粒子,薄壁细胞中发现细胞膜系统的畸变：质膜体（ｐｌａｍａｌｅｍｍａｓｏｍｅ）和双层膜泡囊（ｄｏｕｂｌｅｍｅｍｂｒａｎｏｕｓｖｅｓｉｃｌｅｓ）．质膜体由细胞质膜或液泡膜伸入空泡形成,直径约１０００～２０００ｎｍ,结构类似于类病毒侵染寄主形成的旁壁体．双层膜泡囊是含纤维状物内含物的泡囊,直径约１００～２００ｎｍ,结构类似于某些病毒侵染寄主形成的细胞质泡囊（ｃｙｔｏｐｌａｓｍｉｃｖｅｓｉｃｌｅｓ）和植原体（ｐｈｙｔｏｐｌａｓｍａｓ）,但因其广泛分布于寄主细胞中,不能认为是植原体．文献显示这些病变是类病毒和某些病毒侵染的特征,初步认为云南烟草丛枝症病害可能是病毒病害,发病早期细胞内出现小分子核酸侵染的细胞病变特征,此与莫笑晗等发现病株体内含有大量低分子量ＲＮＡ可能有密切关系．     

Mediation of the attachment or fusion step in vesicular transport by the GTP-binding Ypt1 protein

The function of the guanosine triphosphate (GTP)-binding protein Ypt1 in regulating vesicular traffic was studied in a cell-free system that reconstitutes transport from the endoplasmic reticulum to the Golgi. Blocking the Ypt1 protein activity resulted in accumulation of vesicles that act as an intermediate passing between the two compartments. The Ypt1 protein was found on the outer side of these vesicles. The transport process is completed by fusion of these vesicles with the acceptor compartment, and Ypt1 protein activity was needed for this step. Thus, a specific GTP-binding protein is required for either attachment or fusion (or both) of secretory vesicles with the acceptor compartment during protein secretion.     

云南烟草丛枝症病害研究Ⅲ细胞的超微病变

 超薄切片观察云南烟草丛枝症病害的病叶组织,并抽提试验材料的总核酸电泳检测,结果表明:病组织中检测到与烟草丛枝症病害相关的低分子量RNA,切片中未观察到病毒粒子,薄壁细胞中发现细胞膜系统的畸变:质膜体(plamalemmasome)和双层膜泡囊(double membranous vesicles).质膜体由细胞质膜或液泡膜伸入空泡形成,直径约1000～2000nm,结构类似于类病毒侵染寄主形成的旁壁体.双层膜泡囊是含纤维状物内含物的泡囊,直径约100～200nm,结构类似于某些病毒侵染寄主形成的细胞质泡囊(cytoplasmic vesicles)和植原体(phytoplasmas),但因其广泛分布于寄主细胞中,不能认为是植原体.文献显示这些病变是类病毒和某些病毒侵染的特征,初步认为云南烟草丛枝症病害可能是病毒病害,发病早期细胞内出现小分子核酸侵染的细胞病变特征,此与莫笑晗等发现病株体内含有大量低分子量RNA可能有密切关系.