The Influence of Antibiotics

The bacterial selectivity of antibiotics pertains to an interference with prokaryotic protein synthesis as distinguished from eukaryotic protein synthesis (Muench, in Devlin, 1986, pp. 936,937). As has been indicated, however, some of the antibiotics are too toxic for clinical use, although useful in studying protein synthesis. 

In further confirmation, there are antibiotics prominently listed in Appendices E and E of Hoffman (1999) as inhibitors for enzymes involved in DNA and RNA processes. With regard to cancer treatment, however, a search of Medline indicates that most antibiotics are used against bacterial infections incurred during cancer treatment. An exception involves studies at the M.D. Anderson Cancer Center of the University of Texas, located in Houston. These studies utilized actinomycin D and doxorubicin, both said to be known anticancer agents, in conjunction with the mitotic inhibitors vinblastine and Taxol. (The latter two are from plant extracts, and inhibit cell division or mitosis. The first-mentioned is derived from the Madagascar periwinkle [as is another alkaloid called vincristine], the latter from the yew tree of the 

Pacific Northwest.) Encyclopedic references comment that the antibiotics doxorubicin, daunorubicin, bleomycin, mitomycin, and dactinomycin are all antineoplastic or anticancer agents, but are mostly too toxie for antibiotic use (and perhaps are too toxic to be used as anticancer agents, a ease again of adverse side effects). 

Catharanthus roseus India Vincristine, vinblastine, vindesine 

This information was taken from WHO document No. CAN/TRM/AI. In praise of ethnobotanists, on the same page, Sofowora mentions that selecting anticancer plants on the basis of folkloric information increases the chances of success by a factor of two. 

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Linskens RK, Huijsdens XW, Savelkoul PH, Vandenbroucke-Grauls CM, Meuwissen SG The bacterial flora in inflammatory bowel disease Current insights in pathogenesis and the influence of antibiotics and probiotics. Scand J Gastroenterol 2001 36(suppl 234) 29-40. 

U V-resonance Raman spectroscopy is not only used for bacterial identification but also to study the influence of antibiotics on bacterial cells. The mode of action of amikacin on Pseudomonas aeruginosa cells was studied by Lopez-Diez et al. [83], Neugebauer et al. monitored the effect of ciprofloxacin and moxifloxacin on the chemical composition of B. purnilus and Staphylococcus epidermidis [62, 84],... 

H. D. Hurwitz Professor Chismadjev did not limit himself to the problem of membrane breakdown and membrane fusion which is also tackled by Professor Berg s contribution. Other important aspects of bioelectrochemistry have been treated by Professor Chimadjev, like, for example, the determination of membrane potential, also considered in Professor Adams contribution, the electric field across membrane, the influence of antibiotics and of other vectors for the ion transport. I wish to ask the audience if there are any comments which concern such aspects of the selectivity of cell membranes to ions and the role of peptides. 

The level of antibiotic resistance of the gut flora of pigs has been found to be influenced by factors other than the inclusion of antibiotics in the diet " " such factors include the herd environment, history and the opportunity for cross-contamination. 

The use of zeolites can also be very helpful in removing a reaction product that unfavourably influences the yield of the desired product. Thus, in the manufacture of antibiotic cefoxitin, the amide acylation results in the generation of HCI, which can be removed by the addition of molecular sieve 3 A or 4 A, which has a large capacity for HCI (Weinstock, 1986). Other examples are reactions in which products like methanol or water retard the rate and prevent the reaction to reach the desired degree of completion. Molecular sieves capture methanol or water very well. 

Every few decades a medical innovation is perfected that profoundly influences the practice of medicine. Widespreadvaccinationagainstcommoninfectious agents and the discovery of antibiotics serve as two such examples. Many scientists now believe that the potential of nucleic-acid- and cell-based technologies rivals even the most significant medical advances achieved to date. 

In order to determine the influence of protonation on the conformational preferences of neomycin-B, the structural analysis of the antibiotic was carried out at two different pH values, 4.7 and 9.7, corresponding to the fully protonated and neutral states respectively. 

Modern methods of livestock production are intensive and the environmental conditions stress the animals. The use of antibiotics promotes growth and protects the animals from otherwise certain infection under these conditions. Antibiotic-like compounds formed in lactic acid fermentations prevent proliferation of spoilage and pathogenic microorganisms and increase the shelf life of the products. Nisin is a antimicrobial produced by a lactic acid bacterium and is used in some countries as a food preservative. Some lactic acid bacteria are capable of favorably influencing the fecal flora in man and animals. 

Translational fidelity of bacterial ribosomes is influenced in a more general way by the binding of antibiotics to the ribosome (box 29C). 

G. N. Rolinson, The influence of 6-amino-penidllanic add on antibiotic development, J. Antimicrob. Chemother. 1988, 22, 5-14. 

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