KINETIC ANALYSIS OF CELL SIZE AND DNA CONTENT DISTRIBUTIONS DURING TUMOR CELL PROLIFERATION: EHRLICH ASCITES TUMOR STUDY

In order to study the growth dynamics of proliferating and non-proliferating cells utilizing discrete-time state equations, the cell cycle was divided into a finite number of age compartments. In analysing tumor growth, the kinetic parameters associated with a retardation in the growth rate of tumors were characterized by computer simulation in which the simulated results of the growth curve, the growth fraction, and the mean generation time were adjusted to fit the experimental data. The cell age distribution during the period of growth was obtained and by a linear transformation of the state transition matrices, was employed to specify the cell size and DNA content distributions. In an application of the model, the time-course behavior of cell cycle parameters of Ehrlich ascites tumor is illustrated, and the parameters important for the transition of cells in the proliferating compartment to the non-proliferating compartment are discussed, particularly in relation to the G₁-G₀ and G₂-G₀ transitions of non-cycling cells as revealed by the variation of cell size distribution.     

3'''',5''''-cAMP对艾氏腹水癌细胞膜功能的作用(cAMP的转运和膜蛋白分子的侧向运动)

本工作用外源性cAMP加氨茶碱处理艾氏腹水癌小鼠,于不同瘤龄期观察到癌细胞膜对cAMP的转运功能和膜内蛋白质分子侧向扩散运动的变化、以及膜内可动性蛋白质分子的百分比的改变。这些表型变化均在接种后5—7天最为显著。接种后第7天,实验组癌细胞膜对cAMP的转运加强,而膜内蛋白质分子侧向扩散运动??减慢,抑制率达72.8%,二者P值均小于0.01。而接种后第9天,实验组与对照组之间二者变化均无统计学差异。这些变化表现了癌细胞膜的功能状态的变化。进一步阐明了我们过去工作——3’,5’-cAMP对体内艾氏腹水癌细胞作用机理,接种后第9天癌细胞内cAMP水平升高不是外源性cAMP的积累,而是内源性的代谢结果;阐明了接种后第5天cAMP-PDE活性下降的动因。同时我们也进一步看到膜功能、膜结构和胞质内cAMP水平及其二酯酶活性等变化的动力学关系,以及它们和癌细胞增殖抑制之间的相互关系。从而说明这些变化在癌细胞“逆转”中的意义与其内在联系。     

ConA结合引起的Ehrlich腹水癌细胞成帽能力、入胞作用、表面形态及细胞膜流动性的变化

利用透射电镜下正电荷铁蛋白标记技术,扫描电镜法和荧光偏振技术,发现ConA结合于Ehrlich腹水癌细胞表面可导致细胞成帽能力下降,入胞作用受抑,表面形态简化以及膜流动性下降等变化.讨论了这些变化之间的可能联系.     

艾氏乳腺癌腹水细胞质膜NADH-铁氰化钾氧化还原酶质子泵活性诱导细胞与脂质体融合

在本文中,我们用荧光能量共振转移分析和荧光显微技术证明,小鼠艾氏乳腺癌腹水细胞质膜NADH-铁氰化钾氧化还原反应的电子传递所偶联的质子泵活性能诱导细胞与人工脂质体融合。糖酵解代谢的抑制剂碘乙酸能抑制融合,同时融合过程是吸取质子的。近几年来,我们实验室已报道了多种生物膜质子泵均具有诱导膜融合的功能。因此,质子泵诱导膜融合可能具有比较广泛的生理意义。并为细胞中存在有受能量代谢控制的驱动膜融合的生理机制提供了实验证据。     

绿化林木氯含量、质膜透性与季节的关系及其抗性的初步研究

研究表明:家榆、糖槭、垂柳和中东杨等四种林木叶片氯含量和质膜透性明显随季节的更替而增加,林木受到氯气污染叶绿素含量显著下降。植物对氯气的吸收能力和抗性并不尽一致,家榆对氯的吸收能力很大,但其抗性居中;中东杨对氯的吸收能力和抗性均居中等;糖槭的吸收能力和抗性均较低;垂柳对氯的吸收能力较大,而且具有很强的抗性。     

癌基因表达与膜分子侧向运动和cAMP转运的相关性(环核苷酸对癌细胞作用)

Ehrlich癌细胞在cAMP诱导下,于接种后5-7天癌基因c-myc、c-fos、c-H-ras、c-sis的表达强烈被抑制.与此同时癌细胞膜对cAMP转运增强.膜蛋白分子扩散系数[D]值下降,均以接种后7天最为显著P<0.01.可动分子百分比提高.这反映出癌细胞的分化变异.但至接种后9天,上述癌基因重新表达,膜蛋白分子扩散系数上升,cAMP转运下降,这可能是导致接种后11天癌细胞增殖急剧上升,细胞内cAMP水平下降的原因.说明Ehrlich细胞在去恶化及恶化过程中,癌基因表达变异.膜蛋白分子运动和癌细胞多种表型之间密切相关.     

氯化钾或谷氨酸对人神经母细胞瘤SH-SY5Y细胞钙离子通透性的影响

用人神经母细胞瘤SH-SY5Y细胞系作为研究对象,通过测定细胞存活率(MTT法)和脂质过氧化代谢产物丙二醛(MDA),探讨了氯化钾(KCl)或谷氨酸分别对入神经母细胞瘤SH-SY5Y细胞的损伤作用。结果发现在含Ca     

AN ELECTRON MICROSCOPE STUDY OF THE MORPHOLOGY AND DISTRIBUTION OF THE INTRACYTOPLASMIC "VIRUS-LIKE" PARTICLES OF EHRLICH ASCITES TUMOR CELLS

Electron microscope studies of eight different sublines of Ehrlich ascites tumor cells which had not, as far as could be determined, come in contact with any known virus, revealed dense particles measuring approximately 55 to 70 mµ in diameter, both within and attached to the wall of cytoplasmic vesicles identified as the endoplasmic reticulum. All tumor sublines contained significant numbers of particles and revealed no qualitative or quantitative differences in particle morphology or distribution. It is concluded that these structures are a constant morphological component of the Ehrlich ascites tumor and that they probably do not represent contaminating virus. Their morphology and distribution are described, and the possible interpretations of their significance are discussed.     

刀豆球蛋白A对Ehrlich腹水癌细胞的膜电位和表面电荷的影响

本文报告用荧光探剂diS-C_3—(5)和细胞电泳技术研究刀豆球蛋白A(ConA)作用于Ehrlich腹水癌细胞引起的膜电位和表面电荷的变化.ConA与细胞膜相应受体结合,导致在膜上的diS-C_3-(5)的荧光强度增加,表明细胞去极化.经用缬氨霉素诱导的钾扩散电位校正,与光学讯号变化相应的膜电位变化约是20mv.细胞经G毒毛旋化苷处理后,ConA引起的去极化程度比未处理过的细胞大.ConA作用于Ehrlich腹水癌细胞使细胞电泳迁移率变小.表明细胞表面负电荷数目减少.本文对这些变化的可能机制和相互关系进行了讨论.     

Ca2+对苹果果实细胞膜透性、保护酶活性和保护物质含量的影响

ＣａＣｌ２处理“金冠”苹果果肉圆片,明显地增加Ｃａ２＋含量,降低Ｋ＋外渗。不同浓度Ｃａ２＋程度不同地提高圆片超氧化物歧化酶、过氧化氢酶活性和谷胱甘肽、抗坏血酸含量,降低Ｈ２Ｏ２含量和相对电导率。本文认为：Ｃａ２＋能提高保护酶活性和保护物质含量,有利于保护细胞膜结构。     

THE INFLUENCE OF pH ON ALGAL CELL MEMBRANE PERMEABILITY AND ITS IMPLICATIONS FOR THE UPTAKE OF LIPOPHILIC METAL COMPLEXES1

Uptake of lipophilic metal complexes by freshwater algae has recently been shown to be pH dependent. Here we look at different physiological aspects that could influence the diffusion of the lipophilic Cd complex, Cd(diethyldithiocarbamate)₂⁰ (Cd(DDC)₂⁰), into algal cells at different exposure pH values. Changes in cell membrane permeability were assessed as a function of pH for three species of green algae [Chlamydomonas reinhardtii P. A. Dang., Pseudokirchneriella subcapitata (Korshikov) Hindák, and Chlorella fusca var. vacuolata Shihira et R. W. Kraus] using two neutral, nonionic probes, fluorescein diacetate (FDA) and D‐sorbitol. In parallel experiments, we exposed algae to inorganic Cd or to Cd(DDC)₂⁰ and monitored Cd intracellular metal distribution, together with phytochelatin synthesis. For the three algal species acclimated at pH 5.5 (w/wo DDC 1 μM) and exposed at this pH, their permeability to FDA and D‐sorbitol was consistently lower than for algae growing at pH 7.0 and exposed at this pH (P < 0.001). The ratio of the FDA hydrolysis rate measured at pH 7.0 with respect to the rate measured at pH 5.5 (both in the presence of DDC) correlated with the ratio of the Cd(DDC)₂⁰ initial internalization rate constant obtained at pH 7.0 versus that obtained at pH 5.5 (three algae species, n = 9, r = 0.85, P = 0.004). Our results strongly suggest that acidification affects metal availability to algae not only by proton inhibition of facilitated metal uptake but also by affecting membrane permeability.     

SOME OBSERVATIONS ON DNA CONTENT AND CELL AND NUCLEAR VOLUME GROWTH IN THE DEVELOPING XYLEM CELLS OF CERTAIN HIGHER PLANTS

List , Albert , Jr . (Douglass Coll., Rutgers U., New Brunswick, N. J.) Some observations on DNA content and cell and nuclear volume growth in the developing xylem cells of certain higher plants. Amer. Jour. Bot. 50(4): 320–329. Illus. 1963.—The developing metaxylem cells of Acorus calamus roots undergo an over-all growth in cell and nuclear volume that may be expressed roughly as a constant ratio of relative growth rates. Within this over-all growth picture, however, there is a periodicity of both nuclear and cell volume growth. Other plants such as Peltandra, Eleocharis, and Dennstaedtia undergo a similar volume growth. Marsilea tracheary elements have an increase in nuclear number per cell by simultaneous divisions. Arisaema metaxylem nuclei go through a series of DNA doublings correlated with nuclear volume doubling and cell volume increase, at least up to the 16- or 32-ploid level. The cells display some tendency to fall into size classes, expressing a pulsation in growth. A fluctuating alternation or stepwise growth of cell and nucleus appears to describe the data more suitably than the allometric growth equation. In Zea, the cell and nuclear volumes for metaxylem cells fit a fluctuating envelope better than the straight line, and there is again the probability that cell volumes fall into size classes related to nuclear volume class. The DNA content of the nuclei was determined to fall into a frequency distribution having peaks at the 4-, 8-, 16-, and 32-ploid equivalent, agreeing with an earlier report for diploid maize. DNA content was highly correlated with nuclear volume in the over-all growth of the metaxylem cells.     

植物细胞质膜的分布电荷所引起的电场和细胞内压力

根据细胞双电层模型和电学原理,推出了植物细胞膜上电荷产生的细胞内压力的计算公式。利用该公式分析了植物细胞膜上电荷产生的电磁力对细胞内压力的影响。得出了细胞的实际内压力和植物体的实际刚度比只考虑机械压力的理论结果要大些,细胞的实际破裂情况比只考虑机械压力时的理论分析结果要容易些三点结论。     

INFLUENCE OF CELL VOLUME ON THE GROWTH AND SIZE REDUCTION OF MARINE AND ESTUARINE DIATOMS1

The maximal growth rate (μ_max) of 19 marine and estuarine diatoms decreased with increasing cell volume (V). The relationship between log μ_max (Y) and log V (X) was calculated. Statistical analyses showed that the slope of the equation was not significantly different from those obtained by other researchers and that the 95% confidence intervals of mean μ_max at cell volumes of 10³–10⁵μm³ were not significantly different from those cited in most studies. A new regression line for diatoms was calculated as follows: log μ_max= 0.47–0.14 log V; r =–0.69. The rate of size reduction per generation of the 19 diatom species ranged from 0.03 to 0.87 μm per generation. The rate increased with increasing cell length and cell volume and with decreasing maximum division rate. Statistical analyses showed that the rate was closely related to the cell volume and to the reciprocal of the growth rate. The relationships between maximal growth rate and cell volume and between rate of size reduction and cell volume showed that a diatom with a large volume had a smaller maximal growth rate and a larger rate of size reduction than a diatom with a small volume. The estimates using the equation for the regression line between the rate of size reduction and the reciprocal of maximum division rate indicated that a diatom with a high maximum division rate would need more generation equivalents for a certain size reduction than a diatom with a low maximum division rate, but the periods required for reduction would be approximately equal irrespective of maximum division rate.     

高温胁迫对桃和抽细胞膜透性和光合色素的影响

研究了桃和柚离体叶片在高温胁迫下细胞膜透性（电解质渗漏和Ｐｉ渗漏）和光合色素的变化及其与抗热性的关系。结果表明。（１）高温处理下,无论是黑暗条件下浸水２４ｈ,还是光照条件下浸水２４ｈ,两种果树的电解质和Ｐｉ渗漏都显著增加,光照有利于膜的修复;（２）高温引起Ｃｈｌ含量下降,Ｃｈｌａ／ｂ比值上升;（３）上述这些生理反应与果树的抗热性有关,可用于果树的抗热性鉴定。     

高温胁迫对桃和抽细胞膜透性和光合色素的影响

研究了桃和袖离休叶片在高温胁迫下细胞膜透性（电解质渗漏和Pi渗漏）和光合色素的变化及其与抗热性的关系。结果表明。①高温处理下,无论是黑暗条件下浸水24h,还是光照条件下浸水24h,两种果树的电解质和Pi渗漏都显著增加,光照有利于膜的修复;②高温引起Chl含量下降,Chla／b比值上升;③上述这些生理反应与果树的抗热性有关,可用于果树的抗热性鉴定。     

有机锗化合物对Ehrlich腹水癌小鼠肝脏微粒体细胞色素P-450和UDP-葡萄糖醛酸基转移酶活性的影响

<正> 有机锗化合物有抗肿瘤作用。本文报道双-β乙基碳酸锗倍半氧化物(简称“Ge”)抑制Ehrlich腹水癌实体瘤生长时,宿主肝脏微粒体药物代谢酶和肝组织乳酸脱氢酶(LDH)及微粒体蛋白质含量的变化。     

INFLUENCE OF IRRADIANCE ON CELL VOLUME AND CARBON QUOTA FOR TEN SPECIES OF MARINE PHYTOPLANKTON1

Ten species of marine phytoplankton were grown under a range of photosynthetic photon flux densities (PFDs) and examined for variation in cell volume and carbon quota. Results suggest that in response to low PFDs phytoplankton generally reduce their cell volume and frequently reduce their carbon quota. A significant linear relationship between the log of PFD (I) and cell volume (in nine of ten species) and log I and carbon quota (four of ten species) was demonstrated. When exposed, to a transient in light intensity, Thalassiosira pseudonana (Hustedt, clone 3H) Hasle and Heimdal underwent a rapid adaptation in cell volume and carbon quota. Cells going from low light to high light reached maximum mean cell volume within 5 h, and cells going from high light to low light reached a minimum mean cell volume within 12 h. The resulting kinetic constant (k; a measure of the rate of adaptation) was considerably larger than previously reported k values. Ditylum brightwellii (West) Grunow increased in length but did not increase in width during a transient to increased irradiance. Nutrient limitation was shown to override PFD in determining cell volume and carbon quota for Heterosigma akashiwo Hada. Cells grown at equivalent irradiances but N-limited, were smaller than light-limited and nutrient-saturated cells. Therefore, cell volume and carbon quota do not have the same relationship with PFD when factors other than PFD control growth rate. The ecological implications of reduced cell volumes and carbon quotas with decreasing PFD include possible impacts on CO₂ budgets, an influence on sinking rates, potential changes in predation rates, and surface area/cell volume benefits.     

THE INFLUENCE OF INTRAVASCULAR FLUID VOLUME ON THE PERMEABILITY OF NEWBORN AND ADULT MOUSE LUNGS TO ULTRASTRUCTURAL PROTEIN TRACERS

The permeability of the alveolar-capillary membrane of newborn and adult mice to horseradish peroxidase (HRP) and catalase was studied by means of ultrastructural cytochemistry, and the permeability to ferritin was studied by electron microscopy. The influence of varying volumes of intravenously injected fluid on the rate of leakage of the tracers from pulmonary capillaries was examined. The tracers were injected intravenously and the mice were sacrificed at timed intervals. Experiments on newborn mice with intranasally instilled HRP were also done. The tissues were fixed in formaldehyde-glutaraldehyde fixative. Chopped sections were incubated in Graham and Karnovsky's medium for peroxidase and in a modification of this medium for catalase. Tissues were postfixed in OsO₄ and processed for electron microscopy. In both newborn and adult mice, the ready passage of peroxidase through endothelial clefts was dependent on the injection of the tracer in large volumes of saline. When the tracer was injected in small volumes of saline, its passage through endothelial clefts was greatly reduced. Endothelial junctions of newborn mice were somewhat more permeable to HRP than those of adult mice. In all animals, alveolar epithelial junctions were impermeable to HRP. Catalase and ferritin did not pass through endothelial junctions. Intranasally instilled HRP in newborn mice was taken up by pinocytotic vesicles and tubules of flat alveolar cells.     

亚硒酸钠对肿瘤细胞膜流动性及致癌性的影响

 本文为探讨硒抗肿瘤的机理而开展了硒对小鼠腹水型肝癌(Hep.A)细胞膜流动性影响的研究。结果表明;1.腹水型肝癌细胞膜流动性明显高于正常肝细胞的膜流动性。2.硒能显著降低腹水型肝癌细胞膜的流动性,而对正常肝细胞的膜流动性没有明显影响。3.通过降低腹水型肝癌细胞膜的流动性,可降低肿瘤细胞的致癌力。