对草履虫培养和观察实验的改进

尾草履虫Paramecium caudatum Ehrenberg,又称草履虫、大草履虫,属原生动物门,纤毛纲,是动物界中较原始、较低等、较典型的单细胞动物。其个体较大、结构典型、繁殖快、观察方便、容易采集和培养,不仅生物学教学中以它做代表动物,也用作一种研究模型,在遗传学、细胞生物学、生物化学及生理学等领域广泛应用,在揭示生命的一些基本规律中显示出极大的科学价值。尽管草履虫很容易采集到,但培养和观察草履虫的实验多安排在初冬季节,此时室外温度一般在10℃左右,天然水体中的草履虫密度远远不能满足实验的要求,必须提前进行人工培养。     

一种培养草履虫的新方法

一种培养草履虫的新方法目前,稻草虽是培养草履虫普遍使用的一种材料,由于稻草受农药污染日趋严重,一般简便的稻草场培养方法,往往不能高速繁殖草履虫,达不到理想的种群。数年来我反复实验发现,以菹草（Ｐｏｔａｍｏｇｅｔｏｎｃｒｉｓｐｕｓ）和玉米粉配制的培养液...     

草履虫活体观察实验的一点改进

草履虫是原生动物的典型代表 ,在水里游动非常迅速。要观察活体草履虫必须设法将其固定。一般的实验指导书上通常都是用棉纤维来固定 ,棉纤维直接取于棉絮。这样所取的棉纤维不易分开 ,在显微镜下看到的仅是黑的一片 ,根本看不到草履虫 ,如果作如下改进效果较好。实验室里擦镜纸是必备的 ,擦镜纸既薄又细腻 ,纤维与纤维之间容易分开。我们可以就地取材 ,在载玻片上用镊子刮下少许擦镜纸上的纤维 ,再在刮下的纤维上滴上草履虫培养液 ,然后在显微镜下观察。可以看到在显微镜下一根根纤维纵横交错 ,把草履虫的活动空间隔成一间间小室。草履虫活…     

草履虫的冬季培养

草履虫作为原生动物纤毛纲的代表 ,在动物学教学和实验中是必不可少的 ,在遗传学、细胞生物学、生物化学以及生理学等领域内也被广泛采用 ,且需要量大 ,纯度要求高。关于草履虫的培养方法 ,已有诸多报道 ,这里介绍一种冬季在人工控温条件下用熟鸡蛋黄培养草履虫的方法。1　 草履虫的简易纯化与培养取普通多孔水浴锅一只 ,在锅内安装一只暖棒 (恒温加热器 ,温度范围 16 - 32℃ ) ,加水、通电、调温至 2 5℃ ;同时安放 5 0ｍｌ、 10 0 0ｍｌ烧杯各一只 ,内盛自来水 2 / 3左右。将野外采集的草履虫液在水浴锅中放置一周左右 ,取上层含有草履虫…     

草履虫培养方法的比较研究

草履虫(Paramoecium caudatum)是原生动物门纤毛纲的代表动物,是动物学教学最常用的实验材料之一。传统培养草履虫的方法是用稻草液培养,近年来又有采用玉米粒、玉米雄芯、小麦粒、荷叶、动物组织、蚕黄、葡萄糖、奶粉、干酵母等材料制成培养液进行培养的报道。但究竟哪种方法效果较好,缺乏客观的比较与评价,由此特进行了本试验,旨在筛选较好的培养方法,为有效地培养教学实验动物提供科学依据。     

用紫菜培育和观察草履虫

用市售的紫菜加水 (自然水、自来水均可 )浸泡于容器中 ,10℃以上时把容器放在阳台上 ,或放在恒温箱内 ,控制在 2 0℃以内 ,或放在装有 6 0 W灯泡的泡沫箱内 ,既见光 ,又保温。浸泡后的第 2天 ,低倍镜下镜检紫菜表层浸泡液 ,无任何运动的动物存在。 5 d后 ,镜检紫菜表层浸泡液 ,发现有较多小米粒大小的微小个体在做螺旋式运动或平动 ,7d后 ,低倍镜下检查表层浸泡液 ,有大量形如芝麻粒大小的个体在快速螺旋式运动 ,10 d后(15℃左右 ) ,低倍镜下检查 ,可发现大量形如倒转草鞋状 (又象白瓜形状 )的个体 ,约为 0 .0 1～0 .0 2 cm长 ,后部宽处约…     

几种常见的限制草履虫运动的方法及改进

草履虫在分类上属原生动物门纤毛纲动物。由于它易采集和培养,常被用做中学生物课以及高校生物专业学生学习原生动物的实验材料。但是,草履虫的运动速度较快,这影响了实验者尤其是初学者对草履虫外部形态及内部结构的详细观察,而且草履虫的观察实验一般安排在课程的第一次,因此     

草履虫常年培养

采集和培养草履虫的资料不少,若常年进行大规模培养草履虫就较难控制。经多年探索,取得一种常年采集、培养和综合利用草履虫,解决轮虫、枝角类,水螅、涡虫等淡水无脊椎动物饲养问题的简易方法。     

Axenic Paramecium caudatum. I. Mass Culture and Structure*

SYNOPSIS. To establish and grow Paramecium caudatum in mass axenic culture the culture medium of Soldo, Godoy & van Wagtendonk was modified by substituting phosphatidylethanolamine (PE) for TEM-4T and by a 10-fold increase in folic acid. Population densities of 4000 to 6000 cells/ml and a generation time of 20–26 h are regularly obtained. Optimal growth is obtained with PE-stigmasterol ratios between 40:1 to 400:1. Cells from 1-day-old axenic cultures have many lipid bodies aggregated in clumps (which disappear in 2 to 3 days) as well as foci of rough endoplasmic reticulum bordered by dictyosomes. The latter suggests a very active metabolism. Crystalline sheets found in both food vacuoles and lysosomes presumably play a role in digestion. Axenically grown cells also have abundant Golgi bodies (dictyosomes) and by late log phase become filled with lysosomes.     

Macronuclear Regeneration and Cell Division in Paramecium caudatum

SYNOPSIS. In Paramecium caudatum , occurrence of macronuclear regeneration is closely related to the time of feeding after conjugation. Macronuclear regeneration is induced with a high frequency when conjugating pairs are transferred into fresh culture medium. Feeding immediately after conjugation induces early cell division and 3 or more fissions occur without macronuclear division because of the inability of the macronuclear anlagen to divide. In the cells lacking normal macronuclear anlagen, old macronuclear fragments undergo regeneration and form vegetative macronuclei.     

Ciliary Membranes and Mating Substances in Paramecium caudatum

SYNOPSIS Cilia detached from mating reactive cells of Paramecium caudatum were fractionated for the purpose of identifying the structural component bearing mating substances. Purified axoneme fractions had no mating reactivity. The membrane fraction obtained by dialyzing against a solution of Tris-EDTA (0.1 m m EDTA, 1 m m Tris-HCI, pH 7.6) and 0.6 m KCI, and then by centrifuging over 40% (w/v) sucrose was strongly reactive. No mating reactivity was detected in the soluble fractions containing axonemal and matrix proteins. The results indicate that the mating substances in active from are localized only on the ciliary membranes.     

Temperature-Sensitive Behavior of Paramecium caudatum

SYNOPSIS. The effect of temperature on the behavior of swimming cells of Paramecium caudatum has been investigated by photographic analyses of their tracks in uniform temperature, in temperature gradient, or in temperature changing with time. When the cells were placed in the temperature gradient, the frequency of discontinuous directional changes of cells swimming toward the optimal temperature, the temperature of the culture, was much lower than that of the cells swimming in the opposite direction. This difference in the frequency of directional changes explained the observed accumulation of the cells at - the optimal temperature. When the temperature was suddenly changed toward the optimum, a transient decrease of the frequency of directional changes was observed and when the temperature was changed in the reverse direction, a transient increase of the frequency was noted. This transient response to the temperature change was the origin of the dependence of the frequency of directional changes on the swimming direction in the temperature gradient. Finally, the relation between the magnitude of the transient response and the rate of the temperature change was derived.     

农药胁迫对草履虫个体生长和种群动态的影响

采用连续培养法探讨了草履虫(Paramecium caudatum)在甲胺磷、2,4-D丁酯和甲氰菊酯3种农药胁迫条件下的个体生长和种群动态,并利用Logistic种群增长模型对种群的增长曲线进行了分析.结果表明:甲胺磷和甲氰菊酯农药胁迫能改变草履虫细胞的大小和形态;不同农药不同浓度处理下,草履虫密度增长曲线均具有"S"型生长特点;农药胁迫下草履虫密度增长曲线符合Logistic模型(R2＞0.8),3种农药胁迫下K值明显降低;甲胺磷和甲氰菊酯农药胁迫下种群最大增长率低于2,4-D丁酯胁迫和对照.     

Cd++对草履虫种群的毒性作用

通过研究20℃培养条件下Cd 对草履虫(Paramecium caudatum)种群毒性影响,结果表明:Cd 对草履虫的24hLC50为0.3294mg/L,Cd 浓度对草履虫的种群增长率有极显著影响,多重比较结果显示高浓度组(0.25和0.30mg/L)下草履虫的种群增长率显著小于低浓度下(0.05、0.15和0.20mg/L)的值。回归分析结果表明草履虫种群增长率(Y,/d)与Cd 浓度(X,mg/L)之间呈曲线相关。在一定浓度范围内,草履虫种群增长率随Cd 浓度的升高而呈增大,但高的Cd 浓度显著地降低了草履虫的种群增长率;当Cd 浓度为0.1179mg/L时,草履虫种群有最大增长率1.5442/d。各浓度组与对照组之间的t-检验结果表明在较低的Cd 浓度范围内(0.05、0.10和0.15mg/L)草履虫的种群增长率显著大于对照组的值,而Cd 浓度为0.30mg/L时的草履虫种群增长率显著小于对照组的值。     

Pellicle of Paramecium caudatum as Revealed by Freeze Etching

SYNOPSIS. Freeze etching study of Paramecium caudatum surface reveals a regular pattern formed by depressions equipped with a single or paired cilia. This picture is consistent with the generally accepted concept of Paramecium cortex based on conventional methods of study. The surface of the ciliate is covered with small globular particles ∼14 nm in diameter, which have been found also on the plasma membrane of other cells. In the areas where the tips of trichocysts are attached to the pellicle, the globular particles are arranged into circles 0.4 μm in diameter. The whole surface of Paramecium is covered by a smooth thin layer which, always chipped off during fracturing, is detectable only after etching.     

Developmental expression of macronuclear specific antigen in Paramecium caudatum

We obtained a monoclonal antibody (MA-1) specific for macronuclei of the ciliate Paramecium caudotum and P. dubosqui. Immunoblotting showed that the antigen was a poly-peptide of 50 kilodalton (kDa). During the process of nuclear differentiation in P. caudatum, the MA-1 antigens appeared in the macronuclear anlagen immediately after four out of eight post zygotic nuclei differentiated morphologically into the macro-nuclear anlagen. Afterwards, the antigens could be detected in the macronucleus through the cell cycle, and disappeared when the macronucleus began to degenerate in exconjugant cells. These results suggest that the antigens may play a role in the differentiation and function of the macronucleus. © 1992 Wiley-Liss, Inc.     

Effects of antibiotics on the early infection process of a macronuclear endosymbiotic bacterium Holospora obtusa of Paramecium caudatum

We examined the effects of antibiotics involved in bacterial DNA, RNA and protein synthesis and host protein synthesis on the early infection process of the bacterium Holospora obtusa, a macronucleus-specific symbiont of the ciliate Paramecium caudatum. Infection of the host macronucleus by the bacterium was not inhibited by mitomycin C, rifampicin and chloramphenicol. However, ingestion of the bacterium into the host digestive vacuoles and escape of the bacterium from the vacuoles to the host cytoplasm were significantly arrested with emetine. The results suggest that newly synthesized host proteins play an important role in the early infection process.     

Spiral Motion of Paramecium caudatum in a Small Capillary Glass Tube

SYNOPSIS. The behavior of Paramecium caudatum in small capillary glass tubes was investigated under various ionic conditions and at the various tube diameters. Along the inner walls of the tubes ciliates undergo regular spiral motion, which is completely different from natural spirallings or random walk-like movements observed usually in large vessels. The curvature calculated from the tracks of spiral motions was independent of the inner diameters of capillary tubes, but depend specifically on ionic conditions.
A plausible law governing such regular spiral motions of Paramecium caudatum is proposed. A definite part of the anterior end of a ciliate seems to contact the curved surface of the inner wall of a capillary tube during the motion so that the organism receives a constant tactile stimulus, and the direction of motive force keeps a certain angle against the surface.