ORCID Profile
0000-0003-1101-4048
Current Organisation
Northumbria University
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Elsevier BV
Date: 07-2015
Publisher: Public Library of Science (PLoS)
Date: 25-09-2013
Publisher: Springer Science and Business Media LLC
Date: 29-11-2012
Publisher: Oxford University Press (OUP)
Date: 11-2007
DOI: 10.1111/J.1574-6941.2007.00379.X
Abstract: Two recent, independent advances in ecology have generated interest and controversy: the development of neutral community models (NCMs) and the extension of biogeographical relationships into the microbial world. Here these two advances are linked by predicting an observed microbial taxa-volume relationship using an NCM and provide the strongest evidence so far for neutral community assembly in any group of organisms, macro or micro. Previously, NCMs have only ever been fitted using species-abundance distributions of macroorganisms at a single site or at one scale and parameter values have been calibrated on a case-by-case basis. Because NCMs predict a malleable two-parameter taxa-abundance distribution, this is a weak test of neutral community assembly and, hence, of the predictive power of NCMs. Here the two parameters of an NCM are calibrated using the taxa-abundance distribution observed in a small waterborne bacterial community housed in a bark-lined tree-hole in a beech tree. Using these parameters, unchanged, the taxa-abundance distributions and taxa-volume relationship observed in 26 other beech tree communities whose sizes span three orders of magnitude could be predicted. In doing so, a simple quantitative ecological mechanism to explain observations in microbial ecology is simultaneously offered and the predictive power of NCMs is demonstrated.
Publisher: American Society for Microbiology
Date: 08-2014
DOI: 10.1128/JCM.00764-14
Abstract: Spontaneously expectorated sputum is traditionally used as the s ling method for the investigation of lower airway infections. While guidelines exist for the handling of these s les for culture-based diagnostic microbiology, there is no comparable consensus on their handling prior to culture-independent analysis. The increasing incorporation of culture-independent approaches in diagnostic microbiology means that it is of critical importance to assess potential biases. The aim of this study was to assess the impact of delayed freezing on culture-independent microbiological analyses and to identify acceptable parameters for s le handling. Sputum s les from eight adult cystic fibrosis (CF) patients were collected and aliquoted into sterile Bijou bottles. Aliquots were stored at room temperature before being frozen at −80°C for increasing intervals, up to a 72-h period. S les were treated with propidium monoazide to distinguish live from dead cells prior to DNA extraction, and 16S rRNA gene pyrosequencing was used to characterize their bacterial compositions. Substantial variation was observed in s les with high- ersity bacterial communities over time, whereas little variation was observed in low- ersity communities dominated by recognized CF pathogens, regardless of time to freezing. Partitioning into common and rare species demonstrated that the rare species drove changes in similarity. The percentage abundance of anaerobes over the study significantly decreased after 12 h at room temperature ( P = 0.008). Failure to stabilize s les at −80°C within 12 h of collection results in significant changes in the detected community composition.
Publisher: Wiley
Date: 29-01-2004
DOI: 10.1111/J.1462-2920.2004.00566.X
Abstract: In order for established bioreactors to be effective for treating chemically mixed wastes such as metal working fluids (MWF) it is essential that they harbour microbial populations that can maintain sufficient active biomass and degrade each of the chemical constituents present. In this study we investigated the effectiveness of a bacterial consortium composed of four species (Clavibacter michiganensis, Methylobacterium mesophilicum, Rhodococcus erythropolis and Pseudomonas putida), assembled on the basis of their apparent ubiquity in waste MWF, degradation ability and tolerance to fluctuating chemistry of the waste. The temporal dynamics of the inoculum and its effects on the fate of in idual chemical components of the waste were studied, by regular s ling, over 400 h. Using a complementary approach of culture with chemotaxonomic (FAME) analysis and applying group specific probes (FISH), the inoculum was found to represent a significant component of the community in bioreactors with and without presence of indigenous MWF populations. In addition, the reduction in the COD by the consortium was approximately 85% of the total pollution load, and 30-40% more effectively than any other treatment (indigenous MWF community alone or activated sludge). Furthermore, all the chemical constituents, including the biocide (a formaldehyde release agent) demonstrated > 60% reduction. Many chemical components of the MWF proved to be recalcitrant in the other treatments. The results of this study confirm that assemblage of an inoculum, based on a comprehensive knowledge of the indigenous microbial community, in the target habitat, is a highly effective way of selecting microbial populations for bioaugmentation of bioreactors.
Publisher: Springer Science and Business Media LLC
Date: 09-12-2010
Publisher: Springer Science and Business Media LLC
Date: 18-07-2014
Publisher: BMJ
Date: 15-06-2012
Publisher: Wiley
Date: 19-05-2003
DOI: 10.1046/J.1462-2920.2003.00428.X
Abstract: The ersity of bacterial populations colonizing spatially and temporally separated s les of the same metal-working fluid (MWF) formulation was investigated. Analyses were performed with a view to improve strategies for bioaugmentation of waste MWF in bioreactor systems and prevention of in-use MWF biodeterioration in engineering workshops. Significantly, complementary phenotypic, genotypic and in situ methods revealed that the bacterial communities in operationally exhausted MWFs had low ersity and were similar in species composition from different locations and uses. Of the 179 bacterial isolates studied, only 11 genera and 15 species were identified using fatty acid methyl ester (FAME) analysis, with culture independent analyses by 16S rDNA denaturing gradient gel electrophoresis (DGGE) and fluorescent in situ hybridization being congruent with these FAME data. In order to gain some insight into functional role of detected populations, we correlated the MWF chemical composition and potential pollution load with bacterial abundance and community composition detected within s les.
Publisher: BMJ
Date: 06-04-2013
Publisher: Wiley
Date: 16-05-2012
DOI: 10.1111/J.1462-2920.2012.02762.X
Abstract: Since industrialization global CO(2) emissions have increased, and as a consequence oceanic pH is predicted to drop by 0.3-0.4 units before the end of the century - a process coined 'ocean acidification'. Consequently, there is significant interest in how pH changes will affect the ocean's biota and integral processes. We investigated marine picoplankton (0.2-2 µm diameter) community response to predicted end of century CO(2) concentrations, via a 'high-CO(2) ' (∼ 750 ppm) large-volume (11 000 l) contained seawater mesocosm approach. We found little evidence of changes occurring in bacterial abundance or community composition due to elevated CO(2) under both phytoplankton pre-bloom/bloom and post-bloom conditions. In contrast, significant differences were observed between treatments for a number of key picoeukaryote community members. These data suggested a key outcome of ocean acidification is a more rapid exploitation of elevated CO(2) levels by photosynthetic picoeukaryotes. Thus, our study indicates the need for a more thorough understanding of picoeukaryote-mediated carbon flow within ocean acidification experiments, both in relation to picoplankton carbon sources, sinks and transfer to higher trophic levels.
Publisher: American Society for Microbiology
Date: 2010
DOI: 10.1128/JCM.01324-09
Abstract: S ling of the lower airways of the adult cystic fibrosis (CF) lung has received insufficient detailed consideration, with the importance of s ling strategies for bacteriological outcome not known. Although spontaneously expectorated sputum (SES) s les are often used for diagnostic bacteriological analysis, induced sputum (IS) methods have advantages. This study examined whether significant differences in bacterial content were detected when using a culture-independent, molecular profiling technique to analyze SES or IS s les. Moreover, this work examined what trends relating to bacterial species distributions and reproducibility were found in sequentially induced sputum s les and what implications this has for pathogen detection. Terminal restriction fragment length polymorphism (T-RFLP) analysis was performed on a SES s le and 4 subsequent IS s les taken at 5-min intervals from 10 clinically stable, adult CF patients. This was repeated over 3 s ling days, with variability between s les, induction periods, and s ling days determined. A erse range of bacterial species, including potentially novel pathogens, was found. No significant difference in bacterial content was observed for either SES or serial IS s les. On average, the analysis of a single s le from any time point resolved ∼58% of total bacterial ersity achieved by analysis of an SES s le and 4 subsequent IS s les. The reliance on analysis of a single respiratory s le was not sufficient for the detection of recognized CF pathogens in all instances. Close correlation between T-RFLP and microbiological data in the detection of key species indicates the importance of these findings in routine diagnostics for the detection of recognized and novel CF pathogens.
Publisher: Springer Science and Business Media LLC
Date: 10-11-2015
Publisher: Wiley
Date: 05-09-2008
DOI: 10.1021/BP020131Z
Abstract: Operationally exhausted metal working fluids are chemically mixed, produced in large quantities (400 000 tonnes year in the U.K.), and potentially environmentally toxic. It is essential to develop more reliable and economical approaches for their disposal. We investigated the effectiveness of a defined bacterial consortium, constructed specifically for treating metal-working fluid (MWF), and contrasted its performance to that of undefined inocula from activated sludge. Construction of the consortium was based on knowledge of the ersity of bacterial communities that naturally colonize MWF and determination of their catabolic abilities and tolerance to the chemical constituents. Chemical analysis of the inoculated MWF bioreactor revealed that, after 100 h at 28 degrees C, the defined inoculum reduced the pollution load by over 80% from an initial chemical oxygen demand of approximately 48 000 mg L(-)(1). The inocula performance was approximately 50% more effective than that of the undefined microbial community from the activated sludge. Furthermore, the performance of the constructed consortium was more reproducible than that of an undefined community, an essential feature for bioaugmentation treatment of industrial wastes.
Publisher: American Thoracic Society
Date: 09-2014
Publisher: Frontiers Media SA
Date: 23-12-2021
DOI: 10.3389/FMICB.2021.711134
Abstract: Introduction: The airway microbiota has been linked to specific paediatric respiratory diseases, but studies are often small. It remains unclear whether particular bacteria are associated with a given disease, or if a more general, non-specific microbiota association with disease exists, as suggested for the gut. We investigated overarching patterns of bacterial association with acute and chronic paediatric respiratory disease in an in idual participant data (IPD) meta-analysis of 16S rRNA gene sequences from published respiratory microbiota studies. Methods: We obtained raw microbiota data from public repositories or via communication with corresponding authors. Cross-sectional analyses of the paediatric (& years) microbiota in acute and chronic respiratory conditions, with & case subjects were included. Sequence data were processed using a uniform bioinformatics pipeline, removing a potentially substantial source of variation. Microbiota differences across diagnoses were assessed using alpha- and beta- ersity approaches, machine learning, and biomarker analyses. Results: We ultimately included 20 studies containing in idual data from 2624 children. Disease was associated with lower bacterial ersity in nasal and lower airway s les and higher relative abundances of specific nasal taxa including Streptococcus and Haemophilus . Machine learning success in assigning s les to diagnostic groupings varied with anatomical site, with positive predictive value and sensitivity ranging from 43 to 100 and 8 to 99%, respectively. Conclusion: IPD meta-analysis of the respiratory microbiota across multiple diseases allowed identification of a non-specific disease association which cannot be recognised by studying a single disease. Whilst imperfect, machine learning offers promise as a potential additional tool to aid clinical diagnosis.
Publisher: Wiley
Date: 10-06-2014
Abstract: It is well established that the release of anthropogenic-derived CO2 into the atmosphere will be mainly absorbed by the oceans, with a concomitant drop in pH, a process termed ocean acidification. As such, there is considerable interest in how changes in increased CO2 and lower pH will affect marine biota, such as bacteria, which play central roles in oceanic biogeochemical processes. Set within an ecological framework, we investigated the direct effects of elevated CO2, contrasted with ambient conditions on the resistance and resilience of marine bacterial communities in a replicated temporal seawater mesocosm experiment. The results of the study strongly indicate that marine bacterial communities are highly resistant to the elevated CO2 and lower pH conditions imposed, as demonstrated from measures of turnover using taxa–time relationships and distance–decay relationships. In addition, no significant differences in community abundance, structure or composition were observed. Our results suggest that there are no direct effects on marine bacterial communities and that the bacterial fraction of microbial plankton holds enough flexibility and evolutionary capacity to withstand predicted future changes from elevated CO2 and subsequent ocean acidification.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Chris van der Gast.