Comparison of DMSO and glycerol as cryoprotectants for ascites tumor cells

Summary Mouse Ehrlich ascites and rat D23 ascites tumors were stored in liquid nitrogen under identical conditions for up to 3 years. Cell viability (trypan blue exclusion) and transplantability of both tumors in animals remained virtually unaffected if preserved in 10% DMSO containing medium, whereas, cells preserved in 10% glycerol failed to produce lethal tumors in rodents.This work was performed at the Cancer Research Unit, Royal Victoria Infirmary, Newcastle Upon Tyne, England. I thank John Geggie for expert technical assistance; to the North of England Council of the Cancer Research Campaign and the National Science Foundation (ENG-78-25432) for financial support; and to Dr John A. Dickson for advice and encouragement. Also, I am indebted to Professor Rakesh K. Jain for his support.     

Antigenic differences between a primary hamster lymphosarcoma and its liver metastases

An antiserum was raised in rabbits against a primary metastasizing lymphosarcoma (ML) of the hamster. This was made tumor-specific by absorption with normal hamster tissue extracts. Immunoglobulin-G was prepared and tested for its cytotoxicity towards cells derived from the primary tumor and its liver metastases. The ML-specific IgG was found to be 2--5 times more cytotoxic for cells derived from the primary tumor compared to cells obtained from liver metastases.     

Satellite phage TLCφ enables toxigenic conversion by CTX phage through dif site alteration

Bacterial chromosomes often carry integrated genetic elements (for example plasmids, transposons, prophages and islands) whose precise function and contribution to the evolutionary fitness of the host bacterium are unknown. The CTXφ prophage, which encodes cholera toxin in Vibrio cholerae, is known to be adjacent to a chromosomally integrated element of unknown function termed the toxin-linked cryptic (TLC). Here we report the characterization of a TLC-related element that corresponds to the genome of a satellite filamentous phage (TLC-Knφ1), which uses the morphogenesis genes of another filamentous phage (fs2φ) to form infectious TLC-Knφ1 phage particles. The TLC-Knφ1 phage genome carries a sequence similar to the dif recombination sequence, which functions in chromosome dimer resolution using XerC and XerD recombinases. The dif sequence is also exploited by lysogenic filamentous phages (for example CTXφ) for chromosomal integration of their genomes. Bacterial cells defective in the dimer resolution often show an aberrant filamentous cell morphology. We found that acquisition and chromosomal integration of the TLC-Knφ1 genome restored a perfect dif site and normal morphology to V.?cholerae wild-type and mutant strains with dif(-) filamentation phenotypes. Furthermore, lysogeny of a dif(-) non-toxigenic V.?cholerae with TLC-Knφ1 promoted its subsequent toxigenic conversion through integration of CTXφ into the restored dif site. These results reveal a remarkable level of cooperative interactions between multiple filamentous phages in the emergence of the bacterial pathogen that causes cholera.     

薄膜显微结构的研究

采用复型技术,在透射电镜中观察到厚度大于0.5μm的蒸发淀积Al膜的显微结构,实验结果表明,膜的表面呈岛状结构,侧面呈柱状结构,同时也探讨了影响“柱”直径大小的因素。     

水流量标准装置微机化的研究

本文研究将微型计算机引入容器稳压法的水流量标准装置。从性能、价格等因素出发,采用两台低价的单板机构成双机主-从并行系统,满足了水流量标准装置实时控制和数据处理并行工作的要求,其结果降低了水流量标准装置对流量稳定性的苛刻要求。     

稀土元素多元杂多配合物振动光谱的研究

稀土元素含钼杂多酸根配合物,含钼、钨杂多酸根配合物,以及钒、钼或钨混合多元杂多酸根配合物,共100余种,首次被合成出来。测定了它们的 IR 光谱,通过与相应的 Keggin 结构和 Dawson 结构的 IR 光谱比较,对某些主要谱带进行指认,讨论了它们的特征与变化规律。