关键词： 细胞产量   哺乳动物细胞   悬浮培养   细胞生长   培养液   悬浮状态   单层培养   鸡胚细胞   长春生物制品研究所   毒性作用   动物   微载体培养   胰蛋白酶   疫苗生产   原代细胞   传代细胞系   病毒性疾病   病毒病   传染病   细胞培养   培养(生物)   组织培养技术   血清  

摘要： 组织培养技术自1907年 Ross 将蛙胚髓管部分的小片组织,培养于蛙的淋巴液凝块中,在显微镜下观察到神经节细胞伸出突出,向前生长,算起已经有几十年的历史。她已广泛地应用于生物学、免疫学、细胞学、遗传学、肿瘤学、医学、药物学等许多科学领域,目前应用较多的还是病毒学和分子生物学的研究方面。它不仅对于已知病毒提供了进一步的认识,而且发现了很多新病

关键词： Animals   Cells, Cultured   Cyclic AMP/physiology*   Macromolecular Substances   Mutation   Phosphorylation   Protein Kinases/genetics*  

关键词： Science   Humanities and Social Sciences   multidisciplinary  

摘要： Mycoplasmas are common contaminants of animal cells in cell cultures1–3. About 25 Mycoplasma and Acholeplasma species have been identified as cell culture contaminants but the most frequent are Mycoplasma hyorhinis, Mycoplasma orale, Mycoplasma arginini and Acholeplasma laidlawii3. These species are responsible for almost 85% of the contaminations in cell cultures3. We have devised a method for the selective killing of mycoplasmas in contaminated cell cultures, based on the differential nucleic acid metabolism of mycoplasma and mammalian cells. Mycoplasmas are unusual in that they have a nutritional requirement for nucleic acid precursors which can be met by purines and pyrimidine bases or by nucleosides4–6. Mammalian cells, on the other hand, incorporate very little free pyrimidines7,8 and for that reason incorporation of free bases such as uracil has been used to detect mycoplasmas in contaminated cell cultures9. One of the free base analogues which can be incorporated selectively into nucleic acids of mycoplasmas is 5-bromouracil (5-BrUra). Visible light induces breaks in 5-BrUra-containing DNA10 and this photosensitivity can be greatly increased by binding of the fluorochrome 33258-Hoechst to DNA11. Its unusually high content of A + T makes the mycoplasma DNA3 an excellent candidate for the induction of breakage by the combined action of 5-BrUra, 33258-H and light because 33258-H has a high affinity for A−T base pairs and an even higher affinity for A–BrUra base pairs12. We report here that treating them in this way provides a practical and simple method for the selective killing of contaminating mycoplasmas; they are probably killed by the breakage of their DNA.

关键词： Animals   Cell-Free System   Cells, Cultured/metabolism*   Colchicine/pharmacology   Cricetinae   Dactinomycin/pharmacology   Glycoproteins/biosynthesis*   Mice   Microtubules/metabolism*   RNA, Messenger/metabolism*   Tubulin/biosynthesis*   Tubulin/genetics   Tubulin/metabolism   Vinblastine/pharmacology  

摘要： Colchicine and nocodazole [R 17934] both depolymerize microtubules in cultured fibroblasts [Swiss mouse embryo fibroblast 3T6 cells and Chinese hamster ovary CHO cells] and lead to a rapid inhibition of tubulin synthesis. The level of translatable tubulin mRNA is greatly reduced in drug-treated cells as demonstrated by translation in a reticulocyte-derived in vitro protein synthesizing system. A model of tubulin synthesis regulation is proposed in which the elevated level of unpolymerized tubulin in drug-treated cells inhibits the formation of new tubulin mRNA and the preexisting message decays rapidly. In agreement with this model, tubulin message is short-lived and has an .apprx. 2 h half-life in cells treated with actinomycin D. The proposed model predicts that destabilization of microtubules without a concomitant increase in free tubulin will not inhibit tubulin synthesis. Vinblastine also disrupts microtubules but leads to the aggregation of tubulin into large paracrystals with an apparent decrease in the concentration of free tubulin. This drug does not inhibit tubulin production but rather leads to a measurable enhancement of tubulin synthesis.

关键词： 流行性乙型脑炎病毒   细胞   乙脑病毒   感染性  

摘要： 杀细胞性流行性乙型脑炎病毒(乙脑病毒)接种到兔肾传代细胞(MA—111)产生广泛的细胞病变,细胞层破坏,极少活存下

关键词： Alkaline Phosphatase/metabolism   Animals   Anti-Bacterial Agents/pharmacology*   Bucladesine/pharmacology   Butyrates/pharmacology   Butyrates/pharmacology   Calcimycin/pharmacology*   Calcium/pharmacology   Carboxylic Acids   Cell Line   Cells, Cultured/drug effects*   Clone Cells   Cricetinae   Drug Antagonism   Female   Gangliosides/biosynthesis   Hela Cells   Humans   Lactose Synthase/metabolism   Neoplasm Proteins/biosynthesis   Ovary   Photomicrography   Protein Biosynthesis   Sialyltransferases/metabolism  

摘要： The morphological changes induced by butyrate in HeLa cells and by monobutyryl or dibutyryl cAMP in CHO cells are prevented by micromolar concentrations of the divalent cation ionophore A23187. The ionophore is unable to prevent such changes in medium from which calcium is omitted. At slightly higher (but nontoxic) concentrations, the ionophore inhibits the butyrate-mediated induction of the ganglioside biosynthetic enzyme, sialyltransferase, in HeLa. In CHO, sialyltransferase activity is normally high and not altered by any of the compounds tested.

关键词： Amino Acids/analysis   Cell Division   Cell Survival   Cells, Cultured*   Culture Media*   Glycine*   Molecular Weight   Peptides/analysis   Peptones/analysis*  

摘要： Amino acid analyses of two biologically efficacious fractions from a peptone dialysate (PD) revealed high concentrations of glycine, presumably present in PD as glycine-rich peptides. Before undertaking further analyses of PD, the growth-promoting abilities of several commercially available glycine peptides were tested with strain L (NCTC 2071) cells continuously subcultured in chemically defined medium NCTC 135, and with RH-PD cells which require peptone or peptone fractions for continued survival and proliferation. NCTC 2071 populations 5 to 10% greater than control cultures were obtained with 0.18 to 0.72 mM peptide-supplemented medium NCTC 135; slightly better results were obtained with peptides containing an even number of glycine residues. No amplification of this response was observed after 28 to 29 weekly culture transfers in 0.72 mM supplemented NCTC 135, and evidence suggested that the peptides were poorly hydrolyzed to monomeric glycine. Addition of the glycine peptides may permit use of a reduced minimum inoculum for NCTC 2071. Marked growth enhancement of peptone-dependent RH-PD cells was obtained only when glycine peptides were tested in the presence of 0.5 mg of PD per ml.

关键词： Science   Humanities and Social Sciences   multidisciplinary  

摘要： The uptake of exogenous DNA by mammalian cells in culture may amount to 5% of the host cell complement This material is found within the nucleus, but most of it is not incorporated into the chromosomes.

关键词： Culture Techniques*   Culture Techniques*   DNA/biosynthesis  

摘要： Biotechnology-derived protein drugs, usually referred as biologics, represent a significant part of the whole pharmaceutical market. Typically, biologics are produced in genetically modified animal cells, which are regarded by many engineers and practitioners in the pharmaceutical industry as extremely sensitive to hydrodynamic forces. Since during research or normal operation in the biopharmaceutical industry cells are exposed to a range of hydrodynamic forces, this shear sensitivity idea often leads to very mild, sub- optimal designing and operating conditions. To determine the actual levels of hydrodynamic stress capable of affecting the metabolism or viability of a cell line in bioprocessing or analytical devices, a microfluidic contracting-expanding device was developed in our group that exposes cells to controlled, well-defined hydrodynamic forces by means of keeping the flow in laminar conditions. Using this device, changes in cell behavior can be determined as a function of the local energy dissipation rate (EDR). EDR is a scalar value that is intrinsic to any moving fluid, is independent of the flow regime (turbulent/laminar) and accounts for both shear and extensional components of three-dimensional flow. It represents the rate at which work is done on a fluid element or a cell. If laminar flow is maintained, EDR can be reliably calculated using well-established equations for simple geometries or computational fluid dynamics (CFD) software for more complex problems. The microfluidic device, consisting of a micro-channel bored in a stainless steel sheet in sandwich between two polycarbonate plates, was used in different setups to imitate the environment cells will experience in both bioprocessing and analytical equipment. As a model for analytical devices, it was selected a Fluorescent Activated Cell Sorter (FACS), where cells are forced through a nozzle and interrogated by a laser beam. This instrument was mimicked by passing the cells once through the mic