Antibiotics mode of action

Johnston NJ, Mnkhtar TA, Wright GD. (2002) Streptogramin Antibiotics Mode of action and resistance. Curr Drug Targets 3 335-344. 

Lactams can act as acylating agents to those nucleophiles that effect the cleavage of the (3-lactam Ni C2 bond. Indeed, irreversible acylation of an enzyme amino acid unit belonging to a bacterial cell is the most common type of molecular mechanism for the (3-lactam antibiotics mode of action. Similarly, the process is on grounds of... 

Zhang, L. et al. 2000. Regulated gene expression in Staphylococcus aureus for identifying conditional lethal phenotypes and antibiotic mode of action. Gene 255, 297-305. 

Chopra, I. Roberts, M. (2001) Tetracycline antibiotics mode of action, applications, molecular biology, and epidemiology of bacterial resistance. Microbiol Mol Biol Rev, 65,232-260. 

H. Nikaido in M. Stalton and G. A. Shockman, eds., jd-Eactam Antibiotics Mode of Action, Recent Developments and Future Prospects, Academic Press,... 

Canepari P, Boaretti M, del Mar Lleo M, Satca G. Lipoteichoic add as a new target for activity of antibiotics Mode of action of daptomycin (LY14603Z). Amimicrob Agent Chemotber 1990 34 1220-1226. 

Mechanism of Action. The mechanisms by which antibiotic adrninistration at subtherapeutic levels enhance growth rate and efficiency of gain in growing animals have not been clarified. Possible modes of action include disease control, nutrient sparing, and metaboHc effects. There is extensive evidence that the principal benefit from subtherapeutic use of antibiotics results from the control of harmfiil microorganisms. 

The nutrient sparing effect of antibiotics may result from reduction or elimination of bacteria competing for consumed and available nutrients. It is also recognized that certain bacteria synthesize vitamins (qv), amino acids (qv), or proteins that may be utilized by the host animal. Support of this mode of action is found in the observed nutritional interactions with subtherapeutic use of antibiotics in animal feeds. Protein concentration and digestibiHty, and amino acid composition of consumed proteins may all influence the magnitude of response to feeding antibiotics. Positive effects appear to be largest... 

Antibiotics have a wide diversity of chemical stmctures and range ia molecular weight from neat 100 to over 13,000. Most of the antibiotics fall iato broad stmcture families. Because of the wide diversity and complexity of chemical stmctures, a chemical classification scheme for all antibiotics has been difficult. The most comprehensive scheme may be found ia reference 12. Another method of classifyiag antibiotics is by mechanism of action (5). However, the modes of action of many antibiotics are stiU unknown and some have mixed modes of action. Usually within a stmcture family, the general mechanism of action is the same. For example, of the 3-lactams having antibacterial activity, all appear to inhibit bacterial cell wall biosynthesis. 

Griseofulvin. Although this antibiotic was first isolated ia 1939 and was described as a metabohte of Penicilliumgmeofulvum (20), its action against Microsporum and Trichophyton was only discovered ia 1958. Several modes of action were suggested for (+) 7... 

You should have concluded that because these structures are very diverse, it is unlikely that they will act in the same way. This is, in fact, true the mode of action differs from one class of antibiotics to another. We have listed some modes of action of antibiotics in Table 6.1. 

Antibiotic Producer organism Activity Site or mode of action... 

The clinical aspects of several antibiotics such as penicillin G, cephalosporin and many other antibiotics are summarised in Table 11.1. The potential microorganisms for the production of various antibiotics and then activities on site or mode of action of the antibiotics are also listed. 

Systematic screening experiments have identified more than 100 synthetic compounds with potent antiangiogenic activity. The mode of action for most of these molecules is not well understood, but some of the 40 compounds are well advanced in clinical trials (Table 3). The first substance to have entered clinical trials was the Fumagillin-derivative AGM 1470. Fumagillin is an antibiotic which inhibits bFGF- and PDGF-induced endothelial cell proliferation. The mechanism of action of AGM 1470 is poorly understood, but it was shown that it binds and inhibits the metalloprotease methionine aminopeptidase (MetAp-2). 

Amphotericin B, is a polyene antibiotic, used in the therapy of systemic fungal infections. Its mode of action exploits differences in membrane composition between the pathogen and the human host. Ergosterol, the predominant sterol of fungi, plants, and some protozoan parasites, interacts with Amphotericin B, resulting in an increased ion permeability of the membrane. Humans contain cholesterol, which has a low affinity for amphotericin B. 

Studies on the mode of action of the penicillins in inhibiting bacterial cell-wall biosynthesis suggest that the members of this class of antibiotics (including the closely related cephalosporins) are conformationally restricted substrate analogs... 

The mode of action of starch capped copper nanoparticles (SCuNPs) was compared with that of the well-known antibiotic amphicillin (Fig. 9). There was a drastic decrease in the optical density of compounds containing SCuNPs and ampicillin, ultimately reaching almost zero suggesting that there were no more bacteria present in the culture. AmpiciUin at a concentration of 100 pg/ml has the ability to lyse E.coli almost immediately [29]. The same effect was produced by SCuNPs at 365 ng/ml concentration. The cell lysis occurs at the expense of the fact that at the point of cell division there occurs a deformation of the cell envelope. The decrease in optical density is possibly associated with the cell-envelope deformation occurring at the point of cell division [30]. 

Pharmaceutical microbiology may be defined as that part of microbiology which has a special bearing on pharmacy in all its aspects. This will range fiom the manufacture and quality control of pharmaceutical products to an understanding of the mode of action of antibiotics. The full extent of microbiology on the pharmaceutical area may be judged fiom the chapter contents. 

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