Cell walls agents

Cell wall agents, such as glycopeptides, have concentration-independent bactericidal activity, and the time over which the antibiotic serum concentration persists over the minimal inhibitory concentration of the pathogen is a main pharmacodynamic determination of the outcome. In a two-way, randomized, open, two-period, crossover study in 10 healthy adults, teicoplanin given in two 200 mg doses intramuscularly produced steady-state trough concentrations even higher than those after once-daily intravenous administration of 400 mg (3). Conversion from intravenous to intramuscular administration may therefore allow better compliance with preserved efficacy. Intramuscular teicoplanin was well tolerated. Adverse effects reported were mild local pain for 2-3 hours, headache, and backache. 

Resistance to antimicrobial agents is of concern as it is well known that bacterial resistance to antibiotics can develop. Many bacteria already derive some nonspecific resistance to biocides through morphological features such as thek cell wall. Bacterial populations present as part of a biofilm have achieved additional resistance owkig to the more complex and thicker nature of the biofilm. A system contaminated with a biofilm population can requke several orders of magnitude more chlorine to achieve control than unassociated bacteria of the same species. A second type of resistance is attributed to chemical deactivation of the biocide. This deactivation resistance to the strong oxidising biocides probably will not occur (27). 

Antituberculin Agents. Rifampin [13292-46-17, a semisynthetic derivative of rifamycin SV, is a most valuable dmg for treatment of tuberculosis, an infection caused by mycobacteria, leprosy, and an expanding range of other infections (23). Cycloserine [64-41-7] has been used to a limited extent for treatment of tuberculosis as a reserve dmg. Although cycloserine inhibits bacteria by interfering with their cell wall biosynthesis, it has toxic side effects in humans in the form of neurotoxicity. Capreomycin [11003-38-6] and to a much lesser extent viomycin [32988-50-4] both of which are peptides, have also been used for treatment of this disease. 

Deoxyribonuclease (DNAase), an enzyme that degrades deoxyribonucleic acid, has been used in patients with chronic bronchitis, and found to produce favorable responses presumably by degrading the DNA, contributed by cell nuclei, to inflammatory mucus (213). Lysozyme [9001 -63-2] hydrolyzes the mucopeptides of bacterial cell walls. Accordingly, it has been used as an antibacterial agent, usually in combination with standard antibiotics. Topical apphcations are also useful in the debridement of serious bums, cellulitis, and dermal ulceration. 

Lysozyme is an enzyme that hydrolyzes polysaccharide chains. It ruptures certain bacterial cells by cleaving the polysaccharide chains that make up their cell wall. Lysozyme is found in many body fluids, but the most thoroughly studied form is from hen egg whites. The Russian scientist P. Laschtchenko first described the bacteriolytic properties of hen egg white lysozyme in 1909. In 1922, Alexander Fleming, the London bacteriologist who later discovered penicillin, gave the name lysozyme to the agent in mucus and tears that destroyed certain bacteria, because it was an enzyme that caused bacterial lysis. 

Addition of chelating agents to the fermentation medium may help to inhibit phage multiplication by prevention of phage adsorption to the cell wall. 

The cell walls of mycobacteria contain three structures peptidoglycan, an arabinogalactan polysaccharide and long chain hydroxy fatty acids (mycolic acids) which are all covalently linked. Additional non-covalently attached lipid components found in the wall include glycolipids, various phospholipids and waxes. The lipid-rich nature of the mycobacterial wall is responsible for the characteristic acid-fastness on staining and serves as a penetration barrier to many antibiotics. Isoniazid and ethambutol have long been known as specific antimycobacterial agents but their mechanisms of action have only recently become more clearly understood. 

Some by-products from the food industry contain high proportions of plant cell walls which can be used in human nutrition to produce "dietary fibre" or "functional fibre", i.e. compounds which can be used for their water-holding/binding properties, oil-binding capacity,... or as a source of polysaccharides such as pectins which are suitable after extraction, as gelling or thickening agents. 

Many plant products are very rich in cell wall materials. Cereal brans, seed hulls, various pulps (including beet pulp), citrus peels, apple pomace... are typical exemples of such by-products (1,2). They can be used after simple treatments as dietary fibres, functional fibres or bulking agents, depending on the nutritional claims (2). They can be used also eis sources of some polysaccharides. 

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