Have other than the normal number are aneuploid if

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Unformatted text preview: e Aneuploid. If the cells form tumors when they are injected into animals, they are considered to be Neoplastically Transformed. What Are Some of the Problems Faced by Cultured Cells? Avoiding Contamination CHO-K1 cells – a widely used continuous (transformed) cell line derived from adult Chinese hamster ovary tissue in 1957. © © Photomicrograph of a low level yeast infection in a liver cell line (PLHC-1, ATCC # CRL2406). Budding yeast cells can been seen in several areas (arrows). At this low level of contamination, no medium turbidity would be seen; however, in the absence of antibiotics, the culture medium will probably become turbid within a day. 4 Cell culture contamination is of two main types: chemical and biological. Chemical contamination is the most difficult to detect since it is caused by agents, such as endotoxins, plasticizers, metal ions or traces of chemical disinfectants, that are invisible. The cell culture effects associated with endotoxins are covered in detail in the Technical Bulletin: Endotoxins and Cell Culture (Ref. 10). Biological contaminants in the form of fast growing yeast, bacteria and fungi usually have visible effects on the culture (changes in medium turbidity or pH) and thus are easier to detect (especially if antibiotics are omitted from the culture medium). However, two other forms of biological contamination, mycoplasmas and viruses, are not easy to detect visually and usually require special detection methods. There are two major requirements to avoiding contamination. First, proper training in and use of good aseptic technique on the part of the cell culturist. Second, properly designed, maintained and sterilized equipment, plasticware, glassware, and media. The careful and selective (limited) use of antibiotics designed for use in tissue culture can also help avoid culture loss due to biological contamination. These concepts are covered in detail in a Corning Technical Bulletin: Understanding and Managing Cell Culture Contamination (Ref. 7). Finding A “Happy” Environment To cell culturists, a “happy” environment is one that does more than just allow cells to survive in culture. Usually, it means an environment that, at the very least, allows cells to increase in number by undergoing cell division (mitosis). Even better, when conditions are just right, some cultured cells will express their “happiness” with their environment by carrying out important in vivo physiological or biochemical functions, such as muscle contraction or the secretion of hormones and enzymes. To provide this environment, it is important to provide the cells with the appropriate temperature, a good substrate for attachment, and the proper culture medium. Many of the issues and problems associated with keeping cells “happy” are covered in the Corning Technical Bulletin: General Guide for Identifying and Correcting Common Cell Culture Growth and Attachment Problems (Ref. 8). Temperature is usually set at the same point as the bo...
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