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1.
对维生素E、微量元素锌和硒对大鼠肝脏细胞胶原代谢的调控进行了体外研究。结果表明:肝细胞和储脂细胞均参与肝脏的胶原代谢;环境中维生素E浓度的提高可抑制肝细胞和储脂细胞的核酸合成,对细胞蛋白合成的促进作用不明显,但对细胞胶原蛋白的合成却有选择性抑制作用;环境中微量元素锌和硒浓度的适当提高对肝细胞和储脂细胞的核酸增殖和蛋白质合成均有明显促进作用,但对细胞胶原蛋白合成具有相对抑制作用,若锌和硒的浓度过高则对细胞有损害。总之,营养环境的不同将大大影响肝脏胶原的代谢,因此对肝病病人给予合理的营养膳食可能有助于防止肝硬化的恶化。  相似文献   

2.
Cultered hepatic stellate cells were induced to elongate long, multipolar cellular processes by interstitial collagen gel used as a substratum, as compared to flattened or round cell shapes on polystyrene surface or on Matrigel containing the basement membrane components, respectively. The process induction was inhibited by several reagents as follows: (1) anti-integrin α2 antibody; (2) an oligopeptide, DGEA, an integrin-binding sequence in type I collagen molecule; (3) wortmannin, a phosphatidylinositol 3-kinase inhibitor. Protein tyrosine phosphorylation was enhanced throughout cells including cellular processes by culturing on type I collagen gel. Dual fluorescence staining showed that the core of the processes contained microtubules, whereas the periphery of the processes comprised fibrillar actin. Thus, the process extension was found to depend on integrin-binding to type I collagen fibres, followed by signal transduction and cytoskeleton assembly. The cellular processes included interstitial collagenase and vitamin A-containing lipid droplets. The lipid droplets and vitamin A-autofluorescence were increased by retinyl acetate addition to the culture medium, suggesting an important role of processes in hepatic stellate cell function.  相似文献   

3.
Evidence for the presence of a sulfated polysaccharide component within the extracellular matrix of Platydorina caudata Kofoid is presented. In situ staining with alcian blue and toluidine blue O indicates accumulation of a sulfated polysaccharide in the matrix. The entire matrix was readily solubilized by a hot aqueous extraction and a sulfated proteoglycan complex was isolated. Thin-layer chromatography of hydrolysates and infrared analysis and chemical desulfation of the intact molecule indicate that the polysaccharide component is principally an arabinogalactan with ester-linked sulfate groups. Protease treatment of the extract revealed two distinct bands separable on cellulose acetate electrophoresis. The slower moving component was a sulfated glycoprotein while the faster moving component was a sulfated mucopolysaccharide essentially free of protein. This is the first report of specific chemical analyses and electrophoretic separation of a sulfated polysaccharide within the matrix of a member of the Volvocales. The cytochemistry and electrophoretic patterns of the P. caudata preparation are compared with the same type of extract made from Chlamydomonas reinhardtii Dang. The possible evolutionary significance of the electrophoretic patterns is presented.  相似文献   

4.
肺血管平滑肌细胞是肺血管收缩反应的主要执行者,也是肺血管结构重建的重要参与者。本研究观察了内皮素1(ET1),一氧化氮(NO)和缺氧对培养的新生小牛肺动肺平滑肌细胞(PASMC)钙内流以及胶原合成的影响。结果表明ET1和缺氧可促进PASMC的钙内流,NO供应剂硝普钠(SMP)可抑制ETI诱导的钙内流,其作用呈剂量依赖性,SNP还可以剂量依赖地抑制PASMC的胶原合成,而缺氧可促进PASMC的胶原合成。  相似文献   

5.
The filamentous desmid Spondylosium panduriforme (Heimerl) Teiling var. panduriforme f. limneticum (West & West) Teiling (Desmidiaceae), strain 072CH-UFCAR, is surrounded by a well-defined, mucilaginous capsule consisting of a capsular polysaccharide (CPS). This microalga also produces an extracellular polysaccharide (EPS), which can be isolated from the culture medium. Analysis of the carbohydrate composition of the two polymers by gas chromatography showed that they were different. Both were composed, of galactose, fucose, xylose, arabinose, rhamnose, and glucose but in different amounts. For example, glucuronic acid accounts for 24% of the EPS material but only traces were found in the CPS. Significant differences were also found during methylation analysis. Fucose appeared to have a higher degree of branching in the EPS than in the CPS. These branches were located on C-3 and could be the position for the attachment of the glucuronic acid units in the EPS. The glucuronic acid was present as 1→4-linked and terminal units. A possible explanation for the formation of the EPS is suggested.  相似文献   

6.
兔再生肝提取物(RRLE)中含一种对骨髓有明显影响的造血因子。通过给正常Balb/c小鼠体内注射RRLE,1天后骨髓有核细胞总数有意义减少,同时外周血和脾红髓内出现造血祖细胞,并伴贫血。取实验第2天脾细胞培养,CFU—s数明显升高,为混合性克隆形成单位。第4天后骨髓活跃增殖,产生以中性粒细胞系为主的大量骨髓细胞。血网织红细胞与白细胞值有意义升高,RBC值于第9天恢复正常。上述结果提示RRLE中含有与其它造血因子作用不同的细胞因子。  相似文献   

7.
用光镜和电镜技术研究了HL-60细胞在诱导分化过程中的显微与亚显微结构变化,10~(-6)M的维A酸处理6天,细胞按粒系途径定向分化,其核质比例降低,核浓缩、分叶,核仁减少或消失。经RA处理的细胞在电镜下出现下列明显的变化:细胞核浓缩和分叶,异染色质区域增加,约46%细胞显示出类似成熟粒细胞核的亚显微形态特征,胞质中嗜天青颗粒减少,特异颗粒显著增加,两种颗粒的比率发生明显变化;细胞质中微管、微丝的量增加;多聚和单个分散的游离核糖体减少,有些??细胞胞质空泡化;出现主要以微丝为筑架的大型钝形伪足和不规则的表面突起。上述这些变化似可作为HL-60细胞形态分化的标志。维A酸诱导HL-60细胞形态分化具有明显的时间效应关系。1.4%DMSO对HL-60细胞分化的诱导作用类似于10~(-6)MRA,而等剂量的(10~(-6)M)R Ⅰ、RⅡ其作用弱于RA。  相似文献   

8.
紫苏腺毛的形态结构和发育的研究   总被引:2,自引:0,他引:2  
紫苏(Perillafrutescens(L.)Britton)叶上腺毛的研究表明:叶上腺毛主要有两种类型,一是头状腺毛,二是后状腺毛。两类腺毛都是由1个基细胞、1个柄细胞和由分泌细胞组成的头部构成。头状腺毛的头部由1个、2个或4个分泌细胞构成,其头部呈圆球形或半圆球形。盾状腺毛的头部也由1个、2个、4个或8个分泌细胞构成,其分泌细胞横向扩展使头部呈盾状。分泌盛期,大量分泌物充满角质层下间隙。两类腺毛的原始细胞均起源于叶原基或幼叶的原表皮层细胞,它通过两次平周分裂形成1个基细胞、1个柄细胞和1个头细胞,头细胞不分裂或依次进行1—3次垂周分裂,分别形成单细胞、2细胞、4细胞或8细胞的头部。  相似文献   

9.
An ultrastructural study of the nucleus was carried out, during oogenesis of Perinereis cultrifera, accompanied by an autoradiographic and biochemical study of the syntheses of RNA. The nucleus encloses formations deriving from the dispersal of meiotic chromosomes and a voluminous nucleolus. The latter undergoes morphological development of which each stage is characteristic of a stage of oogenesis. The autoradiographic study shows that the synthesis of RNA of extra-nucleolar origin is highly intense in young oocytes (during the stages of previtellogenesis and vitellogenesis) and that it decreases in older oocytes. The synthesis of RNA of nucleolar origin is very weak during previtellogenesis, increases during vitellogenesis, which is the stage at which it reaches its peak, and then decreases during the stages of the development of cortical alveoli and of maturity. These autoradiographic results are confirmed by a biochemical study which shows that once an oocyte diameter of 80 μm is reached (mid-vitellogenesis), the specific radioactivity of 18 and 28 S rRNA and of 4 and 5 S RNA decreases progressively up to the end of oogenesis.  相似文献   

10.
As assayed by fluorescent reporter dyes, nitric oxide (NO) and H2O2, two downstream signaling agents induced by wounding in the alga Dasycladus vermicularis (Scop.) Krasser, can also be induced in unwounded Dasycladus cells by μM Adenosine 5′[γ‐thio]triphosphate (ATPγS) and Adenosine 5′‐[β‐thio]diphosphate (ADPβS), but not by Adenosine 5′‐O‐thiomonophosphate (AMPS). These nucleotide‐induced responses are blocked by pyridoxalphosphate‐6‐azophenyl‐2′,4′‐disulphonic acid (PPADS), an antagonist of animal purinoceptors, and by adenosine, a feed‐back inhibitor of extracellular nucleotide responses in animals. Similar nucleotide‐ and nucleotide‐antagonist responses were observed in Acetabularia acetabulum (L.) P. C. Silva. Significant levels of ATP released from Dasycladus cells were measured at wound sites by a sensitive luciferin‐luciferase assay. Additionally, the normal wound‐induced production of NO and H2O2 in Dasycladus can be blocked by pretreating the cells with PPADS. Our results indicate that nucleotides released from wounds can serve as a signal to trigger wound responses in algae, and that coordinated signaling between extracellular nucleotides and the NO pathway may have been established early during the evolution of plants.  相似文献   

11.
Part of the cytoplasm, which always contains the plastid, of seta-bearing cells of Coleochaete scutata Bréb. rotates clockwise about the base of the seta. Many golgi bodies, vesicles and much endoplasmic reticulum occupy the bridges between the rotating central core of cytoplasm and the stationary peripheral layer of these cells. The setae, which grow from their base, are devoid of organelles other than vesicles and elongate mitochondria. At irregular intervals along the thin seta wall are annular thickenings containing callose. Microtubules which encircle the base of the seta disappear on treatment with colchicine. This drug had no effect on the speed of rotational streaming or the growth rate of existing hairs but did inhibit the development of new setae. Cytochalasin B slowed, but did not stop, streaming after 3 h exposure. However caffeine, but not EDTA, EGTA or the Ca ionophore A23187, reversibly inhibited cyclosis. The mechanism of cytoplasmic rotation is discussed in the light of these drug treatments and the presence of actin in the alga.  相似文献   

12.
Following fertilization, the carposporophyte of Nemalion helminthoides (Velley in With.) Batters differentiates into four distinct regions: the fusion cell, the sterile gonimoblast cells, the carposporangial mother cells and the carposporangia. The gonimoblast is formed by apically dividing, monopodial filaments of limited growth which may later become pseudodichotomous. Upon differentiation of a terminal carposporangium, a gonimoblast filament may continue to grow sympodially. A single carposporangial mother cell may produce carposporangia in several different directions as well as proliferate successive carposporangia within the sporangial walls that remain after carpospore liberation. As the carposporophyte matures, the gonimoblast initial, the stalk cell, the hypogynous and subhypogynous cells fuse. Except for the fusion cell, all cells of the carposporophyte show organelle polarity and contain a distally located, lobed chloroplast and proximal nucleus.  相似文献   

13.
The ultrastructure and histochemistry of developing and mature cell inclusions in vegetative cells of Antithamnion defectum Kylin were examined. Those studied were chloroplast inclusions, cytoplasmic crystals and spherical bodies within the vacuole. Chloroplasts of mature vegetative cells contain an interthylakoidal, apparently noncrystalline deposit of undetermined chemical identity. The bodies are parallel to the long axis of the plastid, are square (0.13 μm) in cross-section, and up to 3 μm long. Spherical vacuolar bodies (0.5–1.5 μum diam) are formed during early stages of vacuole formation by accumulation of protein deposits in swelling endoplasmic reticulum (ER) cisternae. Swelling of smooth ER contiguous to the ER containing the deposits results in the vacuole enclosing the spherical bodies. In mature cells, vesicles appear to be secreted into the preformed vacuole. Cytoplasmic proteinaceous crystalloids develop without a bounding membrane and may serve as protein reserves.  相似文献   

14.
Rhoicosphenia Grun. is a relatively isolated genus among the biraphid diatoms. Morphological changes in an isopolar member of the genus, Rh. genuflexa (Kütz.) Medlin, were investigated using light and scanning electron microscopy. The fully raphid valve showed changes in its flexure that could be correlated with size reduction during its life history from the initial cells to the smallest cells found in the population. Bands showed changes in number (from three to one) related to size reduction. Rh. genuflexa is morphologically similar to Rh. abbreviata (C. Ag.) Lange-Bert. (=Rh. curvata (Kütz.) Grun.), although the two are distinct taxa. These observations support previous contentions that Rhoicosphenia is a natural taxonomic grouping.  相似文献   

15.
16.
鲇肠道黏液细胞的类型、分布、发育及分泌方式研究   总被引:2,自引:0,他引:2  
利用阿利新蓝-过碘酸雪夫氏试剂(AB-PAS,AB染液pH2.6),对鲇(Silurus asotus)肠道黏液细胞的类型与分布进行了研究,同时采用扫描和透射电镜,研究了黏液细胞的发育与分泌方式。结果显示:鲇肠道黏液细胞染色后呈深蓝色、淡蓝色和浅蓝色,主要含有酸性黏多糖:形态上进一步可将其分为囊状、梨状和杯状三种形态。肠道中黏液细胞的分布密度以中肠最高。其次是后肠,前肠最低;肠道黏液细胞由肠黏膜基底层细胞衍生后,不断向肠腔表层推移而发育成熟;发育过程中黏液细胞内富含大小不等的黏原颗粒,其分泌方式为顶浆分泌。  相似文献   

17.
18.
本文总结了用红细胞血影介导正常肝7sRNA进入肝癌细胞的定位及其对细胞DNA复制、转录和蛋白合成的影响。装载~(125)I-78RNA的血影与肝癌细胞融合后,放射自显影标本显示7sRNA在细胞内的分布,主要定位于细胞质,也有见于细胞核内。7sRNA进入细胞后对细胞的DNA复制、转录和蛋白合成有抑制作用。免疫荧光和免疫沉淀法检测肝癌细胞甲胎蛋白合成的结果表明,7sRNA导入晚G_1期同步细胞后继续培养4小时,甲胎蛋白合成减少。由于细胞DNA复制和转录被抑制,在一定程度上影响了甲胎蛋白基因的表达。  相似文献   

19.
Polyploidy is a major feature of angiosperm evolution and diversification. Most polyploid species have formed multiple times, yet we know little about the genetic consequences of recurrent formations. Among the clearest examples of recurrent polyploidy are Tragopogon mirus and T. miscellus (Asteraceae), each of which has formed repeatedly in the last ~80 years from known diploid progenitors in western North America. Here, we apply progenitor‐specific microsatellite markers to examine the genetic contributions to each tetraploid species and to assess gene flow among populations of independent formation. These data provide fine‐scale resolution of independent origins for both polyploid species. Importantly, multiple origins have resulted in considerable genetic variation within both polyploid species; however, the patterns of variation detected in the polyploids contrast with those observed in extant populations of the diploid progenitors. The genotypes detected in the two polyploid species appear to represent a snapshot of historical population structure in the diploid progenitors, rather than modern diploid genotypes. Our data also indicate a lack of gene flow among polyploid plants of independent origin, even when they co‐occur, suggesting potential reproductive barriers among separate lineages in both polyploid species.  相似文献   

20.
利用蛋白银染色技术对采自青岛沿海砂隙的寡毛类纤毛虫Strombidium kielum进行了形态学重描述,发现该种在寡毛类纤毛虫中具有独一无二的纤毛下器模式,因此为其建立了1新属Varistrombidium,特征为具有5条斜穿虫体的体动基列,其中体动基列1和2延伸到虫体背部,终止于虫体尾端。对Varistrombidium kielum(Maeda&Carey,1985)nov.comb.的小亚基RNA序列分析表明,该种位于Strombidiidae科内,与其形态学相近种Omegastrombidium elegans聚在一起。同时对其小亚基RNA序列可变区2的二级结构进行了预测并与其形态学相似种进行了比较。还对Apostrombidium pseudokielum Xuet al.,2009进行了补充性描述。  相似文献   

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