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Reducing agents, culture media

Striking clinical results have been reported in inflammatory and auto-immune diseases, although in a somewhat limited number of cases . A low molecular mass chromosome-breaking agent was identified in the serum of patients with systemic lupus erythematosus. The chromosome aberrations in cultures of normal lymphocytes in the presence of this factor were reduced to normal values by the addition of BESOD to the culture medium... [Pg.18]

Yamanaka et al. [37] described the influence of bioactive organic agents such as nalidixic acid and chloramphenicol (antibiotics) as well as dithio-threitol (a reducing reagent) as additives to the BC culture medium. In this case, not only the crystallization of the fibers and the material properties are influenced but the Gluconacetobacter cells are themselves also changed. [Pg.59]

Despite being more critical for intracellular products, protease action may also occur in extracellular media. For example, in the expression of a baculovirus vector, which is a lytic system, proteases are often expressed and secreted during recombinant protein production, and the problem may assume a critical level. A similar problem occurs in serum-free culture systems. The absence of proteins such as albumin and macroglobulin reduces the protection against proteolysis. In these cases, addition of an antiproteolytic agent to the culture medium is recommended. [Pg.300]

BSA is considered a semi-defined component that may be contaminated with fatty acids and citrate, and also be a possible source of disease agents [47]. When a completely defined culture medium is required, without reducing the rate of embryo developmenL BSA can be replaced with recombinant human semm albumin (HSA), which has equal developmental potential to BSA and is safe for culturing bovine IVF embryos [52]. [Pg.285]

Primary cultures of cortical neurons and astrocytes synthesize and secrete NGF, but their coculture leads to a reduced NGF level in the culture medium, primarily by suppression of glial secretion (Vige et al., 1992). This inhibition can be reversed by decreasing the number of neurons in the culture. Furthermore, IL-1 induction of astrocytic NGF synthesis (Carman-Krzan et al., 1991 Car-man-Krzan and Wise, 1993) is also inhibited by the presence of neurons. The agent(s) responsible for this inhibition could not be found in medium conditioned by neurons nor in a crude membrane or soluble fraction prepared from the cultured neurons. Thus, the authors hypothesized that direct glial-neuronal contact may be required for the inhibition to occur (Vige et al., 1992). [Pg.182]

In some bacteria, vitamin B12 can be replaced in the culture medium by deoxyribosides, thus suggesting that vitamin Bi 2 plays a role in the conversion of ribose to deoxyribose. Diphosphate ribose nucleotide usually serves as the substrate for the enzyme. The 2-hydroxyl group of the ribose nucleotide is directly replaced by a hydrogen. The exact mechanism of the hydrogen transfer is not known, but it is believed to occur in the form of a hybrid ion, which is derived from a reducing agent. [Pg.291]

If lactose-fermenting P. shermanii is used, cheese whey can be used as a substrate. From the whey containing 12% of dry substances, only 50% of lactose is utilized by P. shermanii, producing 1.6-2.2% solution of propionic acid (Bodie et al., 1987). In the combined batch culture, composed of P. shermanii and Lactobacillus casei, lactose is completely utilized and a 3% solution of propionic acid is produced in 52 h. When the medium is partially replaced during cultivation, a 4.5% solution of propionic acid is obtained by raising the concentration of dry substances in the whey up to 18% the production is increased up to 6.5% in mixed culture. For industrial production it is advisable to add a reducing agent to the medium (see above. Chapter 3), then the ratio of propionic to acetic acid will be increased (Emde and Schink, 1990). [Pg.228]

Numerous reductive transformations of nitroaromatic compounds have been described in the literature (Preu6 and Rieger, this volume). These include gratuitous microbial reactions or chemical reductions by reducing agents in the medium. Thus, in iron-reducing cultures, 4-chloronitrobenzene was rapidly converted into 4-chloroaniline (17). These gratuitous reductions proceed via nitroso and hydroxylamino intermediates and are favored under microaerophilic and even more under anaerobic conditions. [Pg.5]

The protocol can be adapted to measure receptor recycling. If radiolabeled antibodies are internalized into cells by incubation at 37°C in the presence of chemokine or other agents, the acid-elution procedure can be used to remove radiolabeled antibodies remaining on the cell surface. If the acid-elution medium is not reduced below pH 3.0, and the washes kept brief and performed at 4°C, then the cells can be returned to 37°C culture (care should be taken to ensure that the endocytic-trafficking properties of cells are not perturbed by the low pH treatment). During a subsequent incubation at 37°C, receptors that recycle will return antibodies to the cell surface. These antibody molecules can be assessed by measuring the radioactivity that becomes accessible to a second round of acid elution. [Pg.206]

Major cell culture process changes such as a change in the cell line used or the development of a new master cell bank and different media such as a switch to chemically defined media to reduce contamination problems from adventitious agents and/or to provide a more consistent medium ... [Pg.228]


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Culture media

Reducing agent

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