Education
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Mar 1980–
Aug 1983University of Tasmania, Australia
Compost microbiology · Ph.D.Australia · Hobart -
Jan 1975–
Jan 1979University of Tasmania, Australia
Environmental Microbiology · BAgSc(Hons)Australia · Hobart
Other
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Scientific MembershipsASM (Australian & American), AWWA, IWA
Publications (127) View all
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Dataset: Thomas amoeba review EST45-3-11
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Article: Eukaryotic diversity in premise drinking water using 18S rDNA sequencing: implications for health risks.
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ABSTRACT: The goal of this study was to characterize microbial eukaryotes over a 12-month period to provide insight into the occurrence of potential bacterial predators and hosts in premise plumbing. Nearly 6,300 partial 18S rRNA gene sequences from 24 hot (36.9-39.0 °C) and cold (6.8-29.1 °C) drinking water samples were analyzed and classified into major eukaryotic groups. Each major group, consisting of free-living amoebae (FLA)/protozoa, algae, copepods, dinoflagellates, fungi, nematodes, and unique uncultured eukaryotic sequences, showed limited diversity dominated by a few distinct populations, which may be characteristic of oligotrophic environments. Changes in the relative abundance of predators such as nematodes, copepods, and FLA appear to be related to temperature and seasonal changes in water quality. Sequences nearly identical to FLA such as Hartmannella vermiformis, Echinamoeba thermarmum, Pseudoparamoeba pagei, Protacanthamoeba bohemica, Platyamoeba sp., and Vannella sp. were obtained. In addition to FLA, various copepods, rotifers, and nematodes have been reported to internalize viral and bacterial pathogens within drinking water systems thus potentially serving as transport hosts; implications of which are discussed further. Increasing the knowledge of eukaryotic occurrence and their relationship with potential pathogens should aid in assessing microbial risk associated with various eukaryotic organisms in drinking water.Environmental Science and Pollution Research 04/2013; · 2.65 Impact Factor -
Article: Molecular Detection of Campylobacter and Fecal Indicators during the Northern Migration of Sandhill Cranes (Grus canadensis) at the Central Platte River.
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ABSTRACT: The annual Sandhill crane (Grus canadensis) migration through Nebraska, which is thought to be a major source of fecal pollution to the central Platte River, is of unknown human health risk. To better understand potential risks, the presence of Campylobacter species and three fecal indicator bacterial groups (Enterococcus spp., Escherichia coli and Bacteroidetes) were assayed by PCR from crane excreta and water samples collected during their stopover at the Platte River, Nebraska in 2010. Genus-specific PCR assays and sequence analyses identified C. jejuni as the predominant Campylobacter species in Sandhill crane excreta. Campylobacter spp. were detected in 48% of crane excreta, 24% of water samples and 11% of sediment samples. Estimated densities of Enterococcus spp. were highest in excreta samples (mean 4.6×10(8) cell equivalent (CE)/g), while water samples contained higher levels of Bacteroidetes (mean 5.1×10(5) CE/100 mL). Enterococcus spp., E. coli and Campylobacter spp. were significantly increased in river water and sediments during the crane migration period, with Enterococcus spp. densities (∼ 3.3×10(5) CE/g) 2-4 orders of magnitude higher than Bacteroidetes (4.9×10(3) CE/g), E. coli (2.2×10(3) CE/g), and Campylobacter spp. (37 CE/g). Sequencing data for the16S rRNA gene and Campylobacter species-specific PCR assays indicated that C. jejuni was the major Campylobacter species present in water, sediments and crane excreta. Overall, migration appeared to result in a significant, but temporary change in water quality in Spring, when there may be a C. jejuni health hazard associated with water and crops visited by the migrating birds.Applied and environmental microbiology 04/2013; · 3.69 Impact Factor -
Article: Legionella pneumophila Transcriptional Response Following Exposure to CuO Nanoparticles.
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ABSTRACT: Copper ions are an effective antimicrobial agent used to control Legionnaires' disease and Pontiac fever arising from institutional drinking water systems. Here we present data on an alternative bactericidal agent, CuO nanoparticles (CuO-NPs), and its efficacy on L. pneumophila. In broth cultures, the CuO-NPs caused growth inhibition, which appeared to be concentration and exposure time dependent. The transcriptomic response of L. pneumophila to CuO-NP exposure was investigated by using a whole genome microarray. The expression of genes involved in metabolism, transcription, translation, DNA replication and repair, and unknown/hypothetical proteins was significantly affected by exposure to CuO-NPs. In addition, expression of 21 virulence genes was also affected by exposure to CuO-NP and further evaluated by quantitative RT-qPCR. Some virulence gene responses occurred immediately and transiently after addition of CuO-NPs to the cells and faded rapidly (icmV, icmW, lepA), while expression of other genes increased within 6-h (ceg29, legLC8, legP, lem19, lem24, lpg1689 and rtxA), 12-h (cegC1, dotA, enhC, htpX, icmE, pvcA and sidF), and others for up to 24-h (legP, lem19 and ceg19), but for most of the genes tested, expression was reduced after 24-h of exposure. Genes like ceg29 and rtxA appeared to be the most responsive to CuO-NP exposures and along with other genes identified in this study may prove useful to monitor and manage the impact of drinking water disinfection on L. pneumophila.Applied and environmental microbiology 02/2013; · 3.69 Impact Factor -
Article: Differential decay of enterococci and Escherichia coli originating from two fecal pollution sources.
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ABSTRACT: Using in situ subtropical aquatic mesocosms, fecal source (cattle manure versus sewage) was shown to be the most important contributor to differential loss in viability of fecal indicator bacteria (FIB), specifically enterococci in freshwater and Escherichia coli in marine habitats. Sunlight exposure and indigenous aquatic microbiota were also important contributors in this study, whose effect on FIB also differed between water types.Applied and environmental microbiology 02/2013; · 3.69 Impact Factor
