Bacterial amphiphiles

Polymers having carbohydrate chains linked to a lipid anchor embedded in a bacterial membrane the term bacterial amphiphiles was suggested5 for these polymers. Lipopolysaccharides of Gram-negative bacteria constitute the best-known example of these polymers. 

Lipooligosaccharide (LOS) bacterial, 25 498 Lipophilic amphiphiles, 24 154-155 Lipophilic interaction dominated substrate recognition, 16 783-786 Lipophilic moieties, 8 706t Lipopolysaccharides (LPS), 4 706 11 47 BPI protein ability to neutralize, 18 257 peptide and protein binding affinity to, 18 256... 

Bacterial siderophores are another class of widespread toxins produced by bacteria. On land, mycobactins and exophilins are the best-known representatives. Those found in the sea, aquachelins, marinobactins, anguibactin, vulnibactin, and aerobactin (Table 12.3.1) are amphiphilic. This is a property that has received great attention for drug delivery problems and in relation to recognition processes (Testa 2000), devising efBcient algorithms for computer calculation (Fisher 2000). 

Abbreviations for biosynthetic types are composed from abbreviations of nucleoside residues of activated forms of the monosaccharide components. 6 See footnote a to Table VI lin. and br. mean linear and branched polysaccharides. c Including other bacterial amphi-philes of Gram-negative, outer membranes. d Including amphiphiles of Gram-positive cell-membranes. 

Shockman, G.D. Wicken, A.J. "Chemistry and Biological Activities of Bacterial Surface Amphiphiles" Academic Press,... 

Naumann, D., Schultz, C., Sabisch, A., Kastowsky, M., Labischinski, H. New insights into the phase behaviour of a complex anionic amphiphile Architecture and dynamics of bacterial deep rough mutant lipopolysaccharide membranes as seen by FTIR, X-ray, and molecular modelling techniques. J Molec Struct 214 (1989) 213-246. 

Lipopolysaccharides are heat-stable complex amphiphilic macromolecules indispensable for the bacterial growth, viability and for the correct assembly of the external membrane they represent a defensive barrier which helps bacteria to resist to antimicrobial compounds and environmental stresses and are involved in many aspects of host-bacterium interactions as recognition, adhesion, colonization, and, in the case of extremophile bacteria, in the survival under harsh conditions (Alexander and Rietschel, 2001 Raetz and Whitfield, 2002 Raetz et al 2007). LPS are also called endotoxins because they are cell-bound and, once released, play a key role in the pathogenesis of Gram-negative infections, in mechanisms as... 

Wicken, A.J. and Knox, K.W., Bacterial cell surface amphiphiles, Biochim. Biophys. Acta, 604, 1, 1980. 

The second possibility of gating MS channels by bilayer tension takes into consideration changes in intrinsic bilayer curvature as a possible trigger for the channel opening (Fig. 3). Experiments on bacterial MS channels suggested that a diverse group of substances with amphipathic or amphiphilic properties... 

Surfactant Effects on Microbial Membranes and Proteins. Two major factors in the consideration of surfactant toxicity or inhibition of microbial processes are the disruption of cellular membranes b) interaction with lipid structural components and reaction of the surfactant with the enzymes and other proteins essential to the proper functioning of the bacterial cell (61). The basic structural unit of virtually all biological membranes is the phospholipid bilayer (62, 63). Phospholipids are amphiphilic and resemble the simpler nonbiological molecules of commercially available surfactants (i.e., they contain a strongly hydrophilic head group, whereas two hydrocarbon chains constitute their hydrophobic moieties). Phospholipid molecules form micellar double layers. Biological membranes also contain membrane-associated proteins that may be involved in transport mechanisms across cell membranes. 

The Gellman laboratories later reported the chemical synthesis of a 17-mer based on the 12-helix forming trani-2-aminocyclopentanoic acids [64]. Charged amine fimctionalities in combination with neutral monomer units were incorporated into the oligomer to provide an amphiphilic secondary structure (Fig. 35). When tested for bactericidal and bacteriostatic activity against a vancomycin-resistant bacterial strain, this material exhibited activity similar to that of a known 23-mer... 

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