Cell membranes, synthesis

The primary mode of action of this class of antimycotics is interference with uptake and accumulation of products required for cell membrane synthesis. In higher concentrations it causes a disturbance of the cellular permeability. Some investigations show an interaction with Fe(M)- ions the compounds acting as chelators. Very high concentrations interfere with the function of fungal mitochondria. 

Inhibition of cell membranes synthesis in microorganisms (beta-lactam antibiotics, vancomycin, cycloserine). 

Table 33-2 lists drugs that exert their primary antibacterial effects by impairing bacterial cell membrane synthesis and function. Clinical use and specific... 

DRUGS THAT INHIBIT BACTERIAL CELL MEMBRANE SYNTHESIS... 

Unfortunately, there are few pure examples of true selective toxicity. Perhaps the best is penicillin. The therapeutic specificity of this antibiotic is based upon the qualitative difference between bacterial cell wall synthesis and mammalian cell membrane synthesis. Synthesis of the former can be inhibited by penicillin while the latter is unaffected. Thus, penicillin is one of the few examples of a drug that can actually cure an illness. A similar example involves the sulfa drugs, which interfere with the synthesis of folic acid, used in nucleic acid formation, in bacteria. While bacteria must synthesize their own folic acid, mammalian cells utilize dietary, preformed folic acid and are not susceptible to interference with its formation. 

Choline is another essential substrate for cell membrane synthesis, as it is a precursor for the biosynthesis of phosphatidylcholine (52). In preliminary clinical studies, [ CJcholine has shown potential for detection of mmors in areas where FDG lacks sensitivity (53-55). High tumor to background ratios were found for many malignant brain tumors. However, in these tumors, [ CJcholine PET did not allow for malignancy grade estimation (Table 1.2) (55). 

The site of cell membrane synthesis was studied with the help of radioautography in Bacillus megaterium KM in which newly assem-... 

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