Imperial College London


Faculty of MedicineDepartment of Infectious Disease

Casual - Other work



+44 (0)20 7594 3717elizabeth.powell




Medical SchoolSt Mary's Campus





Publication Type

5 results found

Shaw AG, Sim K, Powell E, Cornwell E, Cramer T, McClure Z, Li M, Kroll Jet al., 2016, Latitude in Sample Handling and Storage for Infant Faecal Microbiota Studies: The Elephant in the Room?, Microbiome, Vol: 4, ISSN: 2049-2618

BackgroundIn this manuscript we investigate the “stones best left unturned” of sample storage and preparation and their implications for the next-generation sequencing of infant faecal microbial communities by the 16S rRNA gene.We present a number of experiments that investigate the potential effects of often overlooked methodology factors, establishing a “normal” degree of variation expected between replica sequenced samples. Sources of excess variation are then identified, as measured by observation of alpha diversity, taxonomic group counts and beta diversity magnitudes between microbial communities. ResultsExtraction of DNA from samples on different dates, by different people and even using varied sample weights results in little significant difference in downstream sequencing data. A key assumption in many studies is the stability of samples stored long term at -80°C prior to extraction. After two years, we see relatively few changes; increased abundances of lactobacilli and bacilli and a reduction in the overall OTU count. Where samples cannot be frozen, we find that storing samples at room temperature does lead to significant changes in the microbial community after two days. Mailing of samples during this time period (a common form of sample collection from out-patients for example) does not lead to any additional variation.ConclusionsImportant methodological standards can be drawn from these results; painstakingly created archives of infant faecal samples stored at -80 °C are still largely representative of the original community and varying factors in DNA extraction methodology have comparatively little effect on overall results. Samples taken should ideally be either frozen at -80 °C or extracted within two days if stored at room temperature, with mail samples being mailed on the day of collection.

Journal article

Sim K, Powell E, Shaw AG, McClure Z, Bangham M, Kroll JSet al., 2013, The neonatal gastrointestinal microbiota: the foundation of future health?, ARCHIVES OF DISEASE IN CHILDHOOD-FETAL AND NEONATAL EDITION, Vol: 98, Pages: F362-F364, ISSN: 1359-2998

Journal article

Robertson NJ, Faulkner S, Fleiss B, Bainbridge A, Andorka C, Price D, Powell E, Lecky-Thompson L, Thei L, Chandrasekaran M, Hristova M, Cady EB, Gressens P, Golay X, Raivich Get al., 2013, Melatonin augments hypothermic neuroprotection in a perinatal asphyxia model, BRAIN, Vol: 136, Pages: 90-105, ISSN: 0006-8950

Journal article

Powell E, Faulkner S, Bainbridge A, Kereyni A, Kelen D, Chandrasekaran M, Lecky-Thompson L, Price D, Cady E, Raivich G, Golay X, Robertson NJet al., 2011, IMPROVED NEUROPROTECTION WITH MELATONIN-AUGMENTED HYPOTHERMIA VS HYPOTHERMIA ALONE IN A PERINATAL ASPHYXIA MODEL: A RANDOMIZED STUDY, PEDIATRIC RESEARCH, Vol: 70, Pages: 67-67, ISSN: 0031-3998

Journal article

Winckworth LC, Powell E, 2010, Question 1 Does caffeine treatment for apnoea of prematurity improve neurodevelopmental outcome in later life?, Archives of Disease in Childhood, Vol: 95, Pages: 757-759, ISSN: 0003-9888

Journal article

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