Culture media types

When animal cells are removed from the body, the cells can be maintained (or cultured) for prolonged periods, provided the cells are in an appropriate alternative environment. Environmental factors of importance for animal cell culture include the culture medium, substratum (or surface of the culture vessel), and temperature. The substratum (or surface) is a significant factor for those animal cells which grow attached to the surface of the culture container. A number of types of animal cells (such as lymphoid cells) grow in suspension. 

In this in vitro system, the presence of serum in cell culture medium is not necessary, but the type of transwell is important (the total amount of H-triglycerides secreted was two-fold higher when using 3 pm versus 1 pm pore size transwells), and oleic acid supplementation is required for the formation and secretion of CMs as well as the transport of 3-carotene through Caco-2 cells. Finally, the presence of Tween 40 does not affect CM synthesis and secretion in this in vitro cell culture system. Thus, CMs secreted by Caco-2 cells were characterized as particles rich in newly synthesized H-triglycerides (90% of total secreted) containing apolipoprotein B (30% of total secreted) and H-phospholipids (20% of total secreted) and with an average diameter of 60 nm. These characteristics are close to those of CMs secreted in vivo by enterocytes. ... 

Bryant No, you can put these mutant imaginal discs into an adult fly as a culture medium, and they will continue growing, whereas the wild-type disc will stop growing at the normal final size (see Sehnal Bryant 1993 for review). I don t think there is a systemic signal for shutting down growth. 

Induction ofmRNA for pS2 and secretion of cell-type-specific proteins. pS2 was measured in the culture medium of MCF7 cells with the ELSA-pS2 immunoradiometric assay (CIS Bio International, Gif-sur-Yvette, France). Cells were subcultured in 24-well plates for 144 h in 10% CDHuS. The culture medium was centrifuged at 1200g for 10 min to eliminate floating and detached cells. Results are expressed as ng of secreted protein per million cells. The relative-induced protein potency (RIPP) was calculated as 100 X the ratio between the dose of E2 and that of the chemical needed to produce maximal expression of cell-type-specific proteins (pS2). 

The site of assembly of the Lp(a) particle, by covalent linkage of apo-B100 to apo(a), is not definitively established. White et al. (W12) proved in baboon hepatocytes that inside the cell two types of apo(a) existed, of which only the larger form was recovered from the culture medium. The lower-molecular-weight form proved to be a precursor with a prolonged residence time in the endoplasmatic reticulum. Density gradient ultracentrifugation and immunoblot analysis showed that the majority of apo(a) was secreted into the medium in a... 

Beadle and Tatum had found that irradiation of Neurospora spores produced mutants which were incapable of carrying out certain well-defined chemical reactions, and it was at first supposed that as a result of the destruction of a specific gene, the potentiality for producing a particular enzyme was completely lost. The "wild type" of Neurospora could propagate satisfactorily when biotin was the only vitamin-like substance supplied in the culture medium. Of the many mutant strains produced, however, one needed, in addition to biotin, the vitamin riboflavin. Without a supply of riboflavin in the culture medium this so-called "riboflavinless mutant" would not grow. Since riboflavin is a part of an enzyme system always found in Neurospora, it is an obligatory cell constituent and either has to be produced by the cells themselves (as in the wild type) or supplied exogenously in... 

Over 300 peptides isolated in our laboratory were studied in one or more tumor or normal cell cultures [39-44]. Part of the results obtained is summarized in Table 2.3. Over 75% of the peptides showed pronounced proliferative or antiproliferative activity in at least one cell type (Fig. 2.3). As a rule, tumor cells are more sensitive to peptide action. Besides the cell type, experimental conditions such as cell density or composition of the culture medium also affected the overall effect. In several cases (13%, Fig. 2.3) even the sign of the effect was peptide concentration dependent. Generally, experiments with cell cultures conform with the view that the main physiological function of cell and tissue peptidomes is control of long term processes and the homeostatic balance (i.e. cell differentiation, proliferation and elimination). The overall effect of peptide pools is achieved by concerted action of total sets of peptides rather than by single components. The molecular mechanisms of peptide action in cells requires concrete study in each individual case and are the subject of current research. 

Substrates are usually identified using transfected MDCK, Caco-2, or endothelial cell lines that express the transporter of interest. These cell types are grown in a monolayer on a membrane separating two chambers of culture medium (i.e., the TransweU Cell Culture Assay, Coming Costar Corp., Cambridge, MA). Drag is administered into one chamber, and drag transport across the monolayer is... 

The correlations for as discussed above are for homogeneous liquids. Bubbling gas-liquid reactors are sometimes used for suspensions, and bioreactors of this type must often handle suspensions of microorganisms, cells, or immobilized cells or enzymes. Occasionally, suspensions of nonbiological particles, to which organisms are attached, are handled. Consequently, it is often necessary to predict how the values for suspensions will be affected by the system properties and operating conditions. In fermentation with a hydrocarbon substrate, the substrate is usually dispersed as droplets in an aqueous culture medium. Details of... 

There are a variety of types of bioreactors described in the literature. Among them, the stirred tank bioreactor is the most commonly employed due to its record of performance and ease of operation. Cells growing in bioreactors take up nutrients from the culture medium and release products, byproducts, and waste... 

The host bacteria used for production of recombinant proteins are usually E. coli, or Bacillus subtilis they may express proteins at 1 % to over 50% of the cellular protein, depending on such variables as the source, promoter structure, and vector type. Generally the proteins are expressed intracellularly, but leader sequences for excretion may be included. In the latter case, the protein is generally excreted into the periplasmic space, which limits the amount that can be produced. Excretion from grampositive species such as B. subtilis sends the product into the culture medium, with little feedback limitation on total expression level. 

To cultivate microorganisms, culture medium has to be prepared in one of the commonly employed culture vessels a test tube, a flask, a Petri dish, or a fermenter. There are two main types of culture media natural (or empirical, or complex) and synthetic (or chemically defined) media. They vary widely in form and composition, depending on the species of organism to be cultivated and the purpose of the cultivation. 

Sterilization After a suitable culture medium is selected for the cultivation of a specific microorganism, it is poured into a culture vessel. If you use test tubes or flasks as your culture vessel, the ends of test tubes or flasks should be covered with a suitable closure to allow for the exchange of gases with the atmosphere, yet to keep foreign organisms out of the media. Various types of closures are used in the modern laboratory including cotton plugs, plastic foam, screw caps, metal caps, and aluminum foil. 

Of the different types of oral mucosal cell cultures that have been used [47,48], the most commonly used ones are explants of primary cultures. Small pieces of excised buccal or sublingual tissue are placed in a support system and fed with culture medium. The outgrowths obtained from these tissue explants are then transferred and grown in appropriate media. For example, outgrowths of fibroblasts [49] thus obtained have been described. Gibbs and Ponec [50] reconstructed the epithelium of mucosal tissue by placing a tissue biopsy (with the epithelial side upwards) onto a fibroblast-populated collagen gel. The explants obtained were cultured immediately at the air liquid interface until the epithelium had expanded over the gel (2-3 weeks). These explant cultures may retain many of the in vivo tissue characteristics. 

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