POLYGONAL ASPECTS OF CELL FACES. III. CELL SIZE,CELL DIVISION,AND CELL FACE DISTRIBUTIONS

Wheeler , George E. (Brooklyn Coll., Brooklyn, New York.) Polygonal aspects of cell faces. III. Cell size, cell division, and cell face distributions. Amer. Jour. Bot. 50(8): 747–754. Illus. 1963.—The effects of cell size differences on cell face (polygon type) distributions, and the relationship of cell division to these effects were investigated, using published and original data. Only “relative” size was considered, i.e., the size of a body compared with the sizes of contiguous bodies. A preliminary study of mixtures including 2 sizes of nonliving bodies (bubbles or shot) showed that, with increase in number of smaller bodies relative to larger, 4- and 5-gons decrease and 6-gons increase on both large and small bodies (except for 5-gons on small bubbles). Since the cited papers on cells generally include no volume measurements, cell size was assumed to be proportional to number of faces; therefore, the cells from each sample were pooled in 3 groups of different ranges as to number of faces per cell. This device made evident the 4- and 5-gon decreases and the 6-gon increases with increasing size, but only in certain samples;- marked exceptions occurred among others. New data from 2 original samples showed, in general, the correlations described above, but again then; were exceptions. Discrepancies were found to arise from variable division patterns which affect face types both directly, and indirectly through division effects on cell size. It was concluded that relative size is generally less important in determining cell face distributions than are the more direct cell division events, and that size difference effects can be detected only if the other events operate minimally.     

X-RAY MICROANALYSIS IN CELL BIOLOGY AND CELL PATHOLOGY

Electron probe X-ray microanalysis has been used for the last 25 years by biologists to obtain information about the distribution of elements at the cell and tissue level. During this period, progress has mainly been made through the development of more adequate techniques for specimen preparation (mainly low temperature techniques) and quantitative analysis, so that accurate analysis of the physiologically important cellular ions can be carried out. Use ofin vitrosystems and cell cultures may further increase the number of problems to which X-ray microanalysis can be applied. Among the numerous applications of X-ray microanalysis in cell biology and cell pathology, applications in the areas of epithelial ion transport, the role of calcium in secretory and contractile cells, and the role of ions in cell proliferation and cancer are discussed in more detail.     

打碗花生殖细胞,精细胞及卵细胞中的细胞质类核

已有不少超微结构的资料阐明被子植物双亲和单亲母系质体遗传的细胞学基础。近年应用DAPI荧光染色的方法,可快速地从检测质体DNA存在的状况确定被子植物中具双亲遗传潜能的种。从质体的类核存在与否判断质体遗传方式为母系遗传或双亲遗传与已有的遗传分析结论基本一致,只有少数种类是矛盾的。DAPI荧光技术可以认为是研究细胞质遗传机理的一个重要手段。我们曾证明旋花科牵牛属植物生殖细胞、精细胞中存在细胞质类核,确定其具双亲或单亲父系质体遗传的潜能,并用RFLP技术进一步确定其为质体父系遗传型。本研究证明旋花科的打碗花属生殖细胞、精细胞和卵细胞中细胞质类核存在的状况与牵牛属的相似,提供了打碗花可能在质体遗传上与牵牛属 具相同的遗传方式的资料。     

CELL RESEARCH

Editor..in..ChiefZhen DReporting on Basic Research in the Fieldsof Animal and Plant Cell BiologyInstitute of Biochemistry and Cell Biology,Shanghai Institutes for Biological Sciences,Chinese Academy of Sciences     

高血压病红／白细胞变形性的研究

本文观察了52例原发性高血压和24例正常人的红细胞、白细胞变形性,红细胞膜钙泵、钠泵活性,血粘度及血浆粘度,结果发现:原发性高血压组高、中切变率血粘度和钠泵活性显著高于正常组,红细胞变形性和钙泵活性显著高于正常组;红细胞变形性和钙泵活性显著低于正常组.白细胞变形性、低切变率血粘度及血浆粘度与正常组比较无显著差别.原发性高血压组红细胞变形性与年龄、平均动脉压、钙泵活性,高、中切变率血粘度相关.心痛定和川芎嗪治疗后,红细胞变形性显著改善,川芎嗪还能降低高切变率血粘度.结果提示:在高血压病中红细胞变形性降低、血粘度增高的分子水平机制主要是红细胞膜钙泵活性降低。基于微循环的改善,在扩大治疗例数后,心痛定和川芎嗪可能作为降压治疗的优选药与辅助药。     

KINETICS OF CELL RENEWAL, CELL MIGRATION AND CELL LOSS IN THE HAIRLESS MOUSE DORSAL EPIDERMIS

Forty hairless mice were given injections of tritiated thymidine every 4th hour during 10 days. At 24 hr intervals groups of four mice were killed. The numbers of labelled basal and differentiating cells were determined by autoradiography with a stripping film technique. To determine the background activity skin sections from uninjected control mice were subjected to the same stripping film procedure. Another group of hairless mice was given one single pulse labelling with tritiated thymidine. The number of labelled mitoses was scored for 12 hr after the injection. At 10, 12 and 15 hr after the injection, the numbers of labelled basal and differentiating cells were also determined. A mathematical model of cell population kinetics in the epidermis has been suggested. The results of different simulations on this model were compared with the observed results. The curve of mean grain counts under continuous labelling increased from day to day with two well-defined plateaux. The percentage of all labelled cells increased rapidly up to the 3rd day, and thereafter the curves gradually flattened off. When basal cells and differentiated cells were considered separately the labelling index of the basal cells increased rapidly for the first 3 days and then flattened off at the 100% level on the 5th day. The labelling index of the differentiating cells was low during the first 3–4 days. Then a steep increase in the percentage of labelled differentiating cells was seen, but the curve flattened off again close to the 100 % level after the 7th day. The labelled mitosis curve had its maximum 5 hr after the thymidine injection. The curve fell again to almost zero at 12 hr. Ten, 12 and 15 hr after the injection, 6, 7 and 7% respectively of the labelled cells were found in the spinous layer. It was concluded that three grains over each nucleus could be used as lower limit for considering a cell as labelled. On this basis, tritiated thymidine injections every 4th hour can be considered as continuous labelling.     

CELL VOLUME GROWTH AFTER CELL CYCLE BLOCK WITH CHEMOTHERAPEUTIC AGENTS

The effects of various chemotherapeutic agents on the volume of Chinese hamster V79 fibroblasts and murine lymphoma L5178Y cells were studied by electronic volume spectroscopy. Cells arrested in the division cycle by a chemotherapeutic block continued to grow in volume resulting in abnormally large cells unable to reduce their volume by cell division. This was observed in cells treated with colcemid, vinblastine, excess thymidine, hydroxyurea, ARA-C, 5-fluorouracil, actinomycin-D and bleomycin, but not with puromycin or cycloheximide. Increase in cell volume of blocked cells was correlated with a decrease in cell survival as measured by clonogenic ability. The results suggest the possibility of volume spectroscopy for a rapid in vitro test to determine tumor sensitivity to chemotherapeutic agents and the in vivo monitoring of response to chemotherapy. Mechanisms for increased cell kill by a second agent acting selectively on enlarged cells are considered.     

VARIABILITY OF CELL GENERATION TIMES IN A HEPATOMA CELL PEDIGREE

Time-lapse cinematographic analysis of a clone of HTC rat hepatoma cells showed variations in interdivision time within the clone. A positive correlation was found between the interdivision times of mother and daughter cells. The variability of the differences between interdivision times of cells of sister, cousin, second cousin or second-second cousin relationship was calculated. The proportion of cells with large differences in intermitotic times was found to increase with decreasing relationship. The clonal division pattern observed suggests strongly that ‘inherited’factors govern the process leading to cell division but that their effects can be modified.