Heather R Williamson

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Mycobacterium ulcerans, the causative agent of Buruli ulcer, is an emerging environmental bacterium in Australia and West Africa. The primary risk factor associated with Buruli ulcer is proximity to slow moving water. Environmental constraints for disease are shown by the absence of infection in arid regions of infected countries. A particularly mysterious(More)
BACKGROUND Mycobacterium ulcerans is the causative agent of Buruli ulcer (BU). In West Africa there is an association between BU and residence in low-lying rural villages where aquatic sources are plentiful. Infection occurs through unknown environmental exposure; human-to-human infection is rare. Molecular evidence for M. ulcerans in environmental samples(More)
Buruli ulcer is a necrotizing skin disease caused by Mycobacterium ulcerans and associated with exposure to aquatic habitats. To assess possible transmission of M. ulcerans by aquatic biting insects, we conducted a field examination of biting water bugs (Hemiptera: Naucoridae, Belostomatidae, Nepidae) in 15 disease-endemic and 12 non-disease-endemic areas(More)
Electron transfer (ET) through and between proteins is a fundamental biological process. The rates and mechanisms of these ET reactions are controlled by the proteins in which the redox centers that donate and accept electrons reside. The protein influences the magnitudes of the ET parameters, the electronic coupling and reorganization energy that are(More)
A number of studies have suggested that Mycobacterium ulcerans, the etiological agent of Buruli ulcer, may be transmitted to humans by insect bites. M. ulcerans has been isolated from a predaceous aquatic insect, and PCR detection of M. ulcerans DNA in aquatic environments suggests that the organism is widely distributed within many invertebrate taxa and(More)
Buruli ulcer (BU) is an emerging, but neglected tropical disease, where there has been a reported association with disturbed aquatic habitats and proposed aquatic macroinvertebrate vectors such as biting Hemiptera. An initial step in understanding the potential role of macroinvertebrates in the ecology of BU is to better understand the entire community, not(More)
Culture of Mycobacterium ulcerans from Buruli ulcer patients has very low sensitivity. Thus confirmation of M. ulcerans infection is primarily based on PCR directed against IS2404. In this study we compare the genotypes obtained by variable number of tandem repeat analysis of DNA from IS2404-PCR positive cultures with that obtained from IS2404 positive,(More)
The di-heme enzyme MauG catalyzes the oxidative biosynthesis of a tryptophan tryptophylquinone cofactor on a precursor of the enzyme methylamine dehydrogenase (preMADH). Reaction of H2O2 with the diferric form of MauG, or reaction of O2 with diferrous MauG, forms the catalytic intermediate known as bis-Fe(IV), which acts as the key oxidant during turnover.(More)
Pathogens that use multiple host species are an increasing public health issue due to their complex transmission, which makes them difficult to mitigate. Here, we explore the possibility of using networks of ecological interactions among potential host species to identify the particular disease-source species to target to break down transmission of such(More)
In the absence of its substrate, the autoreduction of the high-valent bis-FeIV state of the hemes of MauG to the diferric state proceeds via a Compound I-like and then a Compound II-like intermediate. This process is coupled to oxidative damage to specific methionine residues and inactivation of MauG. The autoreduction of a P107V MauG variant, which is more(More)