Bacteria amphiphiles

Lipoteichoic acid (LTA), which is a characteristic and widespread cell-surface constituent of gram-positive bacteria, is an amphiphile consisting of two covalently-bound distinct parts, i.e., a glycolipid and a hydrophilic poly(glycerol phosphate). 

Martinez JS, Zhang GP, Flolt PD, Jung FIT, Carrano CJ, Haygood MG, Butler A (2000) Self-assembling Amphiphilic Siderophores from Marine Bacteria. Science 287 1245... 

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). 

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. 

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... 

It has been shown that Gram-positive bacteria, such as Escherichia coli, are susceptible to the photosensitizing action of a variety of photosensitizers, among them amphiphilic metalloporphyrins (Pd11) [16], cationic metallophthalocyanines (Zn11) [15,17], or water-soluble derivatives of chlorophylls [18]. 

The characteristic components of the cytoplasmic membrane of Gram-positive bacteria are the amphiphilic macromolecules lipoglycan and lipoteichoic acid [39,40] (O Fig. 8). Lipotei-choic acids possess in their saccharide chain alditol phosphates as characteristic components, whereas lipoglycans are linear or branched polysaccharides linked to diacylglycerol. These molecules may be further substituted by phosphoglycerol residues. Since lipoteichoic acids and lipoglycans are not found in the same bacterium they are believed to replace each other... 

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