共查询到20条相似文献,搜索用时 46 毫秒
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E. Thalmann 《Engineering in Life Science》1989,9(6):511-516
The increased interest in large scale production of biologically active molecules, as for example monoclonal antibodys, hormones, proteins and enzymes, has stimulated a rapid development of different methods to cultivate eukaryotic cells. Further progress in this field of modern biotechnology is expected not only from the selection of more productive cell lines and more efficient cultivation techniques, but also from the improvement in new bioreactor design and operation, which guarantees increased productivity per unit volume and reduces the downstream processing. Most important factors for a new reactor design in future will be the energy- and mass transfer, shear stress and scaleability. The provision of an adequate oxygen supply to large scale reactors is the most critical barrier to scale up. If oxygen is limited in a small degree, the result is inhibition of cell density and cellular efficiency in the production of the desired biomolecules. In addition, when methodologies are used which allow high cell densities and high metabolic active cells, the oxygen transfer becomes more important and, at the same time, more difficult. Since direct sparging of air into the cell-containing medium causes problems such as shear forces and foaming, new, efficient methods in bubble free aeration must be utilized. A new aeration system is presented, which is suitable to bubble-free aeration as well to separation of microcarrier-anchered cells from the harvested medium when running in a continuous perfusion mode. The efficiency of the CHEMCELL System regarding aeration and cell retention is demonstrated by the growth kinetics of BHK 21-cells in batch and perfusion mode. 相似文献
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Takács AP Horváth J Kazinczi G Gáborjányi R 《Communications in agricultural and applied biological sciences》2005,70(3):435-439
Susceptibility of 33 Lycopersicon species and varieties to Tobacco mosaic virus (TMV) and Cucumber mosaic virus (CMV) were studied. Plants were mechanically inoculated with the C/U1 strain of TMV and U/246 strain of CMV. Virus infection was checked by symptomatology, DAS ELISA and back inoculation (biotest). All the studied Lycopersicon species and varieties were susceptible to TMV-C/U1. L. esculentum Mill. convar. infiniens Lehm. var. flammatum Lehm., L. esculentum Mill. convar. fruticosum Lehm. var. speciosum Lehm. and L. esculentum Mill. convar. infiniens Lehm. var. validum Bail. showed extreme resistance to CMV-U/246. The other 30 species and varieties were susceptible to CMV-U/246. New compatible and incompatible host-virus relations have been reported. The extreme resistant Lycopersicon varieties could be used as resistance sources in tomato breeding. 相似文献
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A lethally malformed neonate with mosaic tetrasomy 12p is presented. This is the third reported case of mosaic tetrasomy 12p to have died in the neonatal period. These three babies have shown a consistent phenotype characterized by dysmorphic facies and large diaphragmatic hernia. Mosaic tetrasomy 12p is usually not detectable from lymphocyte investigation, indicating that chromosome studies from cultured fibroblasts should be undertaken in neonates with multiple malformations which include a diaphragmatic defect. 相似文献