Antimicrobial modifications

V. Sedlarik in Antimicrobial Modifications of Polymers, 2013, InTech, Rijeka, Croatia, Chapter 7. 

V. Sedlarik, Antimicrobial modifications of polymers, in Biodegradation—Life of Science (2013), pp. 187-204... 

Thiostrepton family members are biosynthesized by extensive modification of simple peptides. Thus, from amino acid iacorporation studies, the somewhat smaller (mol wt 1200) nosiheptide, which contains five thiazole rings, a trisubstituted iadole, and a trisubstituted pyridine, is speculated to arise from a simple dodecapeptide. This work shows that the thiazole moieties arise from the condensation of serine with cysteiae (159,160). Only a few reports on the biosynthesis of the thiostrepton family are available (159,160). Thiostrepton is presently used ia the United States only as a poly antimicrobial vetetinary ointment (Panalog, Squibb), but thiazole antibiotics have, ia the past, been used as feed additives ia various parts of the world. General (158) and mechanism of action (152) reviews on thiostrepton are available. 

In contrast, Snyder has demonstrated that an RI derivative ofp53 can restore endogenous p53 activity the RI derivative induced apoptosis by activation of endogenous p53 and by restoration of function to several p53 DNA contact mutants. Rl-modified peptides have also been investigated as potential alternatives for bost defense peptides. Indeed, a RI derivative of indolicidin retained tbe antimicrobial and antiendotoxic acitivities of the natural peptide. As the antiendotoxin activities of the Rl-derivative were conserved these results might indicate the conservation of multiple immunomodulatory activities upon retro-inversion, highlighting the potential of this modification for therapeutic applications. 

The items to be tested for sterility should be tested for antimicrobial activity during the product development stages, if this is possible. If they are found to have such activity, preparatory or test procedures will need to be modified to neutralize this activity. If all items are found to be free of such activity when first tested or after modification of procedures, application of the test for antimicrobial activity to every sample is not necessary. 

Polymastiamide A (579), an antimicrobial steroid with an unusual side chain modification involving an amide bond to a non-protein amino acid, was isolated from the Norwegian marine sponge Polymastia boletiformis. The structure of polymastiamide A (579) was elucidated by analysis of spectroscopic data and chemical interconversions [470]. Polymastiamides B-F (580-584), additional amino acid conjugates of steroids, were later isolated from the same sponge [471],... 

Residues of antimicrobial agents tend to be present at their highest levels in the liver and kidney, as well as the site of injection (if that is the route of application). The liver is the main site of biochemical modification of antimicrobial substances, as the body tries to convert them to less toxic... 

Thompson et al. have investigated the ecological role of the brominated isoxazoline alkaloids, aerothionin (Structure 2.84) and homoaerothionin (Structure 2.89), in Californian specimens of A. fistularis.134 139 The alkaloids caused behavioral modification in marine invertebrates, were toxic to dorid nudibranchs other than one specialized feeder, inhibited the settlement and/or metamorphosis of invertebrate larvae, and were strongly antimicrobial and cytotoxic. Sponges exuded significantly more of these two alkaloids when wounded,155 and, consistent with their defensive role, the metabolites were found to be localized in spherulous cells close to the aquiferous exhalant canals.156... 

Abstract In this review, the general principles of antimicrobial surfaces will be discussed in detail. Because many common products that keep microbes off surfaces have been banned in the past decade, the search for alternatives is in full run. In recent research, numerous new ways to produce so-called self-sterilizing surfaces have been introduced. These technologies are discussed with respect to their mechanism, particularly focusing on the distinction between biocide-releasing and non-releasing contact-active systems. New developments in the catalytic formation of biocides and their advantages and limitations are also covered. The combination of several mechanisms in one surface modification has considerable benefits, and will be discussed. 

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