Cholera medium

Vibrio species are difficult to isolate from natural sources as they tend to be present with coliforms, which outgrow them on many media. Several selective media are available, including DCLS Agar which contains sodium desoxycholate, lactose, sucrose, and the indicator Neutral Red, the desoxycholate suppressing the growth of coliforms. Cholera medium works in a similar manner, in that high levels of ox bile are used to suppress the growth of the normal gut flora. 

Hatzinger, P.B. and Stevens, J.L. (1989). Rat kidney proximal tubule cells in defined medium the roles of cholera toxin, extracellular calcium and serum in cell growth and expression of y-glutamyltransferase. In Vitro Cell. Dev. Biol. 25(2) 205-212. 

A-B Toxins are bacterial toxins composed of two peptide chains one (B) that binds to the invaded cell surface, and the other (A) containing the toxin which is then taken-up into the cell. Some examples of exotoxins secreted by the bacteria into the surrounding medium and highly toxic to certain tissues are pathogens causing botuiism (Clostridium botulinum), tetanus (Clostridium tetani) and diptheria (Corynebacterium diphtheria. An example of an A-B endotoxin is Vibrio cholerae. Botulinum toxin and tetanus toxin have their main toxic actions on neuronal tissues, so are described at NEUROTOXINS. 

The M cells found in Peyer s patches have also been suggested to transport particles. These are specialized absorptive cells known to absorb and transport indigenous bacteria (i.e.. Vibrio cholerae)-, macromolecules, such as ferritin and horseradish peroxidase viruses and carbon particles, from the lumen of the intestine to submucosal lymphoid tissue (33,37,38). It has been reported that hydrophobic, negatively charged or neutral particles of size smaller than 5 pm are better taken up by M cells particles smaller than 1 pm in size accumulate in the basal medium, while larger particles remain entrapped in the Peyer s patches (39). Transport of absorbed materials to the systemic circulation... 

Enterotoxins. Toxic proteins formed by bacteria with molecular masses in the range from 27000 to 30000 which are usually excreted into the medium ( exotoxins). E. can be taken up with contaminated food or be formed by the bacteria colonizing the intestinal walls. Finally, the bacteria can penetrate the intestinal walls and then start to excrete the E. Some E. are thermally very stable and survive when food is boiled. E. from Salmonella and Staphylococcus species are the most frequent causes of food poisoning. Shortly after uptake, the symptoms of nausea, vomiting, diarrhea, and circulatory complaints occur. Deaths are rare and occur only when the subject is already in a weakened state. The sites of attack by E. vary, e.g., at intestinal epithelial cells or in the vegetative nervous system. For the production of antitoxins, E. are obtained by lysis of bacterial cells or from cell-free culture filtrates. E. have been detected, e. g., in the following bacterial species Bacillus cereus, Clostridium perfringens, Escherichia coli. Vibrio cholerae. Staphylococcus aureus, and Streptococcus faecalis. 

Escherichia coli normally lives in intestinal tracts and, in particular, in the large intestine of human beings and warm-blooded animals. Outside the intestinal tract, it can only live for a short time in water and in the ground and therefore indicates relatively fresh faecal contamination. Thus, when Escherichia coli is present in water, one also has to reckon on the presence of pathogenic intestinal bacteria such as Salmonella, Shigella and cholera vibrios. Escherichia coli is easy to cultivate on culture mediums and can, by reason of its metabolic characteristics in the so-called... 

The keratinocytes were cultured in primitive medium DMEM supplemented FBS (Fetal Bovine Serum), EGF (Epidermal Growth Factor), hydrocortisone, cholera toxin (Sigma) with the density 3 x 10 cells/cm, 37% ° C, 5% CO2. 

Actin ccosslinking assay. For cleavage site mutant analyses, the actin cross-linking assay was performed as described previously using culture supernatants. In the inliibitor actin ctosslinking assays, 100 pi of VT cholerae culture supernatants were pretreated with the indicated inhibitor at a final concentration of 50 ).iM (1 200 dilution from a 10 mM stock). For exogenous addition, inliibitor was also added to HFFs (in 500 pi DMEM medium) at a final concentration of 50. iM (1 200 dilution from a 10 mM stock). 

---