Molecule biocide

Intrinsic (natural, innate) resistance. In one form of intrinsic resistance, the fungal cell wall (see Chapter 2) is considered to present a barrier to exclude or, more likely, to reduce the penetration by biocide molecules. The evidence to date is sketchy but the available information tentatively links cell wall glucan, wall thickness and consequent relative porosity to the sensitivity of Saccharomyces cerevisiae to chlorhexidine. 

In addition to their use as solvents, surfactants, and biocides, ionic liquids are attractive for use in catalytic reactions due to their ability to activate reactant molecules, the ease of separation from final products, thermal stability, solubility of gaseous reactants, among other properties. Amit Gujar and Mark White (Mississippi State Univ., USA) show, for example,... 

Although this section has been of necessity very brief, the examples chosen illustrate the advantages which can be obtained by including fluorine atoms in bioactive molecules. In turn, the commercial success in this area is prompting fluorine chemists, both academic and industrial, to seach for ever more selective and economic methods for introducing fluorine atoms into molecules with potentially useful biocidal properties. 

There are a great many methods by which small molecules can be assembled to form nanotubes and other similar columnar aggregates [50]. Unlike the stacked disc methodology employed by Fenniri s group, Russell and co-workers took a completely different approach, which consisted of nanotubes made by way of rolled-up bilayers [48], Their study of biocidal nanotubes from a self-assembled diacetylene salt employed a hydrophobically driven bilayer type of self-assembly step. This bilayer formation was based on the alignment of the hydrophobic chains, including aligned Ji-systems of the acetylenes on the interior of the bilayer and the polar hydrobromide salts of an amine on the exterior of the bilayer (Fig. 7.6). 

The photoreactions characteristic for the halogenated phenols and anilines have shown to occur in most members of the series of chlorophenoxy and halophenylurea derivative pesticides, and in some other related biocides as well. Photohydrolysis is a frequently encountered process, but carbene formation has been demonstrated in several cases too. The phototransformation mechanisms of these molecules, however, are frequently complex, owing to the greater complexity of the molecules in question, and homolytic cleavage steps have been found to contribute in several cases. 

In general, it appears that biocide molecules are more recalcitrant than chemotherapeutic agents to inactivation by bacterial enzymes. It has been suggested [76] that chlorhexidine might be inactivated if this is confirmed, then it adds another dimension to mechanisms of bacterial insensitivity to biocides [76],... 

The [D-MeAla] analog of tentoxin has been shown to exist in multiple conformations in solution, which differ in their ability to inhibit coupled election transport in chloroplasts (24). This finding is the first demonstration that conformers of a molecule can have different biological activities, and points to the idea that this kind of behavior might be usefully considered in the design of biocides. 

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