Biomedical subjects
Publications and source records attributed to Alison M Hill.
This review covers the biosynthesis of aliphatic and aromatic polyketides as well as mixed polyketide/NRPS metabolites, and discusses the molecular genetics and enzymology of the proteins responsible for their formation.
A series of novel, well-defined, unsymmetrical poly(ethylene glycol) chains of the type X(OCH(2)CH(2))(n)()Y (where X = protecting group; Y = nucleofuge or a different protecting group; n = 3, 6, 9, 12, 15, 18, and 24) were prepared in high yields by applying orthogonal protecting groups. The purity of the compounds was fully verified by elemental and high-resolution mass spectrometry analyses.
Tuberculosis remains the leading cause of death among infectious diseases, accounting for more than two million deaths annually. The incidence of the disease is increasing globally, partially because of the resurgence of drug-resistant strains of Mycobacterium tuberculosis. Calixarenes are macrocyclic oligomers, some of which are able to modify the growth of M. tuberculosis in infected cells. Most experimental work has been carried out with Macrocyclon, also known as HOC 12.5EO. In this study, we demonstrate that Macrocyclon is effective in controlling M. tuberculosis infections, and we provide evidence that its effect is partially mediated by an l-arginine-dependent mechanism of macrophage activation that involves the activity of the inducible nitric oxide synthase. We also show that Macrocyclon is effective in athymic and major histocompatibility complex class II-/- mice and synthesized a number of structurally related calixarenes expressing significant antimycobacterial activity.
The unusual benzoate starter unit in soraphen A derives from phenylalanine via cinnamate in a beta-oxidative (plant-like) pathway; 3-phenyl-3-hydroxypropanoate incorporates directly into soraphen by loading onto module 2 of the PKS and indirectly from the beta-oxidative pathway to generate benzoyl CoA.
Six novel halogenated soraphen analogues have been isolated from the wild-type producing organism using precursor directed biosyntheses; the best 'delivery vehicle' for the novel starter acids was cinnamate but ortho substituents were not tolerated by the soraphen PKS.
Methodologies to access water soluble large ringed calixarenes in good yield using efficient synthetic procedures have been investigated. Symmetrical partial functionalisations at the lower rim are described using activated [n]ethylene glycol chains and the addition behaviour contrasted with that of bromoalkanenitriles which proceeds with no observed regioselectivity. Full functionalisations of the calixarenes bearing hydrophilic groups are then investigated and a two-step procedure established which appears to be generally applicable for the addition of different [n]ethylene glycol chains. Furthermore, difunctionalisation under different reaction conditions are described. Throughout, strategies for the characterisation of these high mass compounds are outlined.