Basic Concept of Biotechnology 23

  Animal Biotechnology   Animal biotechnology is a broad field encompassing the polarities of fundamental and applied research, including molecular modeling, gene manipulation, development of diagnostics and vaccines and manipulation of tissue. It accounts for the use of biotechnology tools, including molecular markers, stem cells, and tissue engineering. Molecular markers are increasingly being used to identify and select the particular genes that lead to desirable traits and it is now possible to select superior germ plasma and disseminate it using artificial insemination, embryo transfer and other assisted reproductive technologies. These technologies have been used in the genetic improvement of livestock. Transgenesis offers considerable opportunity for advances in medicine and agriculture. In livestock, the ability to insert new genes for such economically important characteristics as fecundity, resistance to or tolerance of other environmental stresses would represent a ...

  Cell Culture Cell culture is one of the major tools used in cellular and molecular biology, providing excellent model systems for studying the normal physiology and biochemistry of cells (e.g., metabolic studies, aging), the effects of drugs and toxic compounds on the cells, and mutagenesis and carcinogenesis. It is also used in drug screening and development, and large scale manufacturing of biological compounds (e.g., vaccines, therapeutic proteins). The major advantage of using cell culture for any of these applications is the consistency and reproducibility of results that can be obtained from using a batch of clonal cells. When the cells are removed from the organ fragments prior to, or during cultivation, thus disrupting their normal relationships with neighboring cells, it is called cell culture. Tissue culture is the general term for the removal of cells from an animal or plant and their subsequent growth in a favorable artificial environment. The cells may be removed fro...

  Density of the Culture: Cells should be subcultured prior to confluence. The ideal method for determining the correct seedingdensity is to perform a growth curve at different seeding concentrations. This allows you to determine the minimum concentration that will give a short lag period and early entry into rapid logarithmic growth.   Exhaustion of Medium: Medium requires periodic replacement. If the pH falls too rapidly, subculture may be required. Time since Last Subculture orRoutine subculture is best performed according to a strict schedule, so that reproducible behavior is achieved. It is essential to become familiar with the growth cell cycle for each cell line. Cells at different phases behave differently with respect to proliferation, enzyme activity, glycolysis and respiration, synthesis of specialized products, etc.   Requirements for Other Procedures: When cells require operations other than routine propagation (e.g., increasing stock, changing vessel or medi...

  Culture Conditions   Culture conditions vary widely for each cell type, but the artificial environment in which the cells are cultured invariably consists of a suitable vessel containing a substrate or medium that supplies the essential nutrients (amino acids, carbohydrates, vitamins, minerals), growth factors, hormones, and gases (O2, CO2), and regulates the physicochemical environment (pH, osmotic pressure, temperature).   Mammalian Cell: Morphology Most mammalian cells in culture can be divided in to three basic categories based on theirmorphology (Fig. 2)   1)         Fibroblastic (or fibroblast-like) cells are bipolar or multipolar and have elongated shapes. They grow attached to a substrate.   2)         Epithelial-like cells are polygonal in shape with more regular dimensions, and grow attached to a substrate in discrete patches.   3)         Ly...

  Aseptic Techniques   To minimize the risk of contamination, follow these 5 rules:   1.          Always check the cells carefully before handling (by eye and on a microscope). Become familiar with the indicators of abnormal cell growth.   2.          Whenever possible, maintain cultures without antibiotics for at least part of the time, to reveal cryptic contamination.   3.          Check sterility of all reagents before use.   4.          Use dedicated media and reagents; do not share with other cell lines.   5.          Maintain a high standard of sterility at all steps. Mycoplasma contamination, which may slow cell growth, cannot be checked under a regular microscope. To confirm or rule out such contamination, use a mycoplasma test (e.g. Roche Applied ...