Mark John Pallen

Mark John Pallen
The University of Warwick · Medical Microbiology and Virology

MA, MBBS, MD, PhD

About

349
Publications
38,066
Reads
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16,175
Citations
Additional affiliations
April 2013 - present
The University of Warwick
Position
  • Professor of Microbial Genomics and Head of Division
July 2001 - March 2013
University of Birmingham
Position
  • Professor of Microbial Genomics
November 1999 - June 2001
Queen's University Belfast
Position
  • Professor of Microbiology

Publications

Publications (349)
Article
Background: The horse plays crucial roles across the globe, including in horseracing, as a working and companion animal and as a food animal. The horse hindgut microbiome makes a key contribution in turning a high fibre diet into body mass and horsepower. However, despite its importance, the horse hindgut microbiome remains largely undefined. Here...
Article
Full-text available
The genus Escherichia has been extensively studied and it is known to encompass a range of commensal and pathogenic bacteria that primarily inhabit the gastrointestinal tracts of warm-blooded vertebrates. However, the presence of E. coli as a model organism and potential pathogen has diverted attention away from commensal strains and other species...
Article
Escherichia coli has a rich history as biology's 'rock star', driving advances across many fields. In the wild, E. coli resides innocuously in the gut of humans and animals but is also a versatile pathogen commonly associated with intestinal and extraintestinal infections and antimicrobial resistance-including large foodborne outbreaks such as the...
Article
Full-text available
We report the recovery of metagenome-assembled genomes (MAGs) from fecal samples collected in 2018 from five healthy adult female pigs in southeast England. The resulting nonredundant catalog of 192 MAGs encompasses 102 metagenomic species, 41 of them novel, spanning 10 bacterial and 2 archaeal phyla.
Preprint
Thousands of new bacterial and archaeal species and higher-level taxa are discovered each year through the analysis of genomes and metagenomes. The Genome Taxonomy Database (GTDB) provides hierarchical sequence-based descriptions and classifications for new and as-yet-unnamed taxa. However, bacterial nomenclature, as currently configured, cannot ke...
Article
Full-text available
The vast majority of described prokaryotic viruses have double-stranded or single-stranded DNA or double-stranded RNA genomes. Until 2020, a mere four prokaryotic single-stranded, positive-sense RNA viruses have been classified in two genera (Riboviria; Lenarviricota; Allassoviricetes; Leviviridae). Several recent metagenomic and metatranscriptomic...
Article
Full-text available
The status Candidatus was introduced to bacterial taxonomy in the 1990s to accommodate uncultured taxa defined by analyses of DNA sequences. Here I review the strengths, weaknesses, opportunities and threats (SWOT) associated with the status Candidatus in the light of a quarter century of use, twinned with recent developments in bacterial taxonomy...
Article
The human oesophagus is home to a complex microbial community, the oesophageal microbiome. Despite decades of work, we still have only a poor, low-resolution view of this community, which makes it hard to distinguish hope from hype when it comes to assessing links between the oesophageal microbiome and cancer. Here we review the potential importanc...
Article
Full-text available
The remarkable success of taxonomic discovery, powered by culturomics, genomics and metagenomics, creates a pressing need for new bacterial names, while holding a mirror up to the slow pace of change in bacterial nomenclature. Here, I take a fresh look at bacterial nomenclature, exploring how we might create a system fit for the age of genomics, pl...
Article
Full-text available
Brachyspira hyodysenteriae is the principal cause of swine dysentery, a disease that threatens economic productivity of pigs in many countries as it can spread readily within and between farms, and only a small number of antimicrobials are authorized for treatment of pigs. In this study, we performed whole-genome sequencing (WGS) of 81 B. hyodysent...
Preprint
Full-text available
Background: The COVID-19 pandemic continues to expand globally, with case numbers rising in many areas of the world, including the Eastern Mediterranean Region. Lebanon experienced its largest wave of COVID-19 infections from January to April 2021. Limited genomic surveillance was undertaken, with just twenty six SARS-CoV-2 genomes available for th...
Preprint
Full-text available
Background Complex carbohydrates that escape digestion in the small intestine, are broken down in the large intestine by enzymes encoded by the gut microbiome. This is a symbiotic relationship between particular microbes and the host, resulting in metabolic products that influence host gut health and are exploited by other microbes. However, the ro...
Preprint
Background The horse plays crucial roles across the globe, including in horseracing, as a working and companion animal and as a food animal. The horse hindgut microbiome makes a key contribution in turning a high fiber diet into body mass and horsepower. However, despite its importance, the horse hindgut microbiome remains largely undefined. Here,...
Article
Full-text available
Background The chicken is the most abundant food animal in the world. However, despite its importance, the chicken gut microbiome remains largely undefined. Here, we exploit culture-independent and culture-dependent approaches to reveal extensive taxonomic diversity within this complex microbial community. Results We performed metagenomic sequenci...
Article
Full-text available
An amendment to this paper has been published and can be accessed via the original article.
Article
Full-text available
Little is known about the genomic diversity of Escherichia coli in healthy children from sub-Saharan Africa, even though this is pertinent to understanding bacterial evolution and ecology and their role in infection. We isolated and whole-genome sequenced up to five colonies of faecal E. coli from 66 asymptomatic children aged three-to-five years i...
Article
Full-text available
Latin binomials, popularised in the 18th century by the Swedish naturalist Linnaeus, have stood the test of time in providing a stable, clear, and memorable system of nomenclature across biology. However, relentless and ever-deeper exploration and analysis of the microbial world has created an urgent need for huge numbers of new names for Archaea a...
Article
Chickens and guinea fowl are commonly reared in Gambian homes as affordable sources of protein. Using standard microbiological techniques, we obtained 68 caecal isolates of Escherichia coli from 10 chickens and 9 guinea fowl in rural Gambia. After Illumina whole-genome sequencing, 28 sequence types were detected in the isolates (4 of them novel), o...
Article
Full-text available
Background: Gene doctoring is an efficient recombination-based genetic engineering approach to mutagenesis of the bacterial chromosome that combines the λ-Red recombination system with a suicide donor plasmid that is cleaved in vivo to generate linear DNA fragments suitable for recombination. The use of a suicide donor plasmid makes Gene Doctoring...
Preprint
Full-text available
Latin binomials, popularised in the eighteenth century by the Swedish naturalist Linnaeus, have stood the test of time in providing a stable, clear and memorable system of nomenclature across biology. However, relentless and ever-deeper exploration and analysis of the microbial world has created an urgent unmet need for huge numbers of new names fo...
Article
Full-text available
Increasing contact between humans and non-human primates provides an opportunity for the transfer of potential pathogens or antimicrobial resistance between host species. We have investigated genomic diversity and antimicrobial resistance in Escherichia coli isolates from four species of non-human primates in the Gambia: Papio papio (n=22), Chloroc...
Preprint
Full-text available
Little is known about the genomic diversity of Escherichia coli in healthy children from sub-Saharan Africa, even though this is pertinent to understanding bacterial evolution and ecology and their role in infection. We isolated and whole-genome sequenced up to five colonies of faecal E. coli from 66 asymptomatic children aged three-to-five years i...
Preprint
Full-text available
Background: The chicken is the most abundant food animal in the world. However, despite its importance, the chicken gut microbiome remains largely undefined. Here, we exploit culture-independent and culture-dependent approaches to deliver a genomic blueprint of this complex microbial community. Results: We performed metagenomic sequencing of fifty...
Preprint
Full-text available
Background. The chicken is the most abundant food animal in the world. However, despite its importance, the chicken gut microbiome remains largely undefined. Here, we exploit culture-independent and culture-dependent approaches to deliver a genomic blueprint of this complex microbial community. Results. We performed metagenomic sequencing of fifty...
Preprint
Full-text available
Background. The chicken is the most abundant food animal in the world. However, despite its importance, the chicken gut microbiome remains largely undefined. Here, we exploit culture-independent and culture-dependent approaches to deliver a genomic census of this complex microbial community. Results. We performed metagenomic sequencing of fifty chi...
Article
Full-text available
Chickens and guinea fowl are commonly reared in Gambian homes as affordable sources of protein. Using standard microbiological techniques, we obtained 68 caecal isolates of Escherichia coli from ten chickens and nine guinea fowl in rural Gambia. After Illumina whole-genome sequencing, 28 sequence types were detected in the isolates (four of them no...
Article
Full-text available
Increasing contact between humans and non-human primates provides an opportunity for the transfer of potential pathogens or antimicrobial resistance between different host species. We have investigated genetic diversity and antimicrobial resistance in Escherichia coli isolates from a range of non-human primates dispersed across the Gambia: patas mo...
Article
Full-text available
Flagellin is the major constituent of the flagellar filament and faithful restoration of wild-type motility to flagellin mutants may be beneficial for studies of flagellar biology and biotechnological exploitation of the flagellar system. However, gene complementation studies often fail to report whether true wild-type motility was restored by expr...
Article
Full-text available
Background: Chickens are a highly important source of protein for a large proportion of the human population. The caecal microbiota plays a crucial role in chicken nutrition through the production of short-chain fatty acids, nitrogen recycling, and amino acid production. In this study, we sequence DNA from caecal content samples taken from 24 chic...
Article
Full-text available
In recent years Bamako has been faced with an emerging threat from multidrug resistant TB (MDR-TB). Whole genome sequence analysis was performed on a subset of 76 isolates from a total of 208 isolates recovered from tuberculosis patients in Bamako, Mali between 2006 and 2012. Among the 76 patients, 61(80.3%) new cases and 15(19.7%) retreatment case...
Article
Among long-stay critically ill patients in the adult intensive care unit (ICU), there are often marked changes in the complexity of the gut microbiota. However, it remains unclear whether such patients might benefit from enhanced surveillance or from interventions targeting the gut microbiota or the pathogens therein. We therefore undertook a prosp...
Preprint
Full-text available
Introduction Understanding mother-to-infant transmission of Group B Streptococcus (GBS) is vital to the prevention and control of GBS disease. We investigated the transmission and phylogenetic relationships of mothers colonised by GBS and their infants in a peri-urban setting in The Gambia. Methods We collected nasopharyngeal swabs from 35 mother-i...
Preprint
Full-text available
Background For long-stay patients on the adult intensive care unit, the gut microbiota plays a key role in determining the balance between health and disease. However, it remains unclear which ICU patients might benefit from interventions targeting the gut microbiota or the pathogens therein. Methods We undertook a prospective observational study...
Article
Full-text available
Enteroaggregative Escherichia coli (EAEC), is a diarrhoeagenic human pathogen commonly isolated from patients in both developing and industrialized countries. Pathogenic EAEC strains possess many virulence determinants, which are thought to be involved in causing disease, though, the exact mechanism by which EAEC causes diarrhoea is unclear. Typica...
Article
Full-text available
Background Across the world, ticks act as vectors of human and animal pathogens. Ticks rely on bacterial endosymbionts, which often share close and complex evolutionary links with tick-borne pathogens. As the prevalence, diversity and virulence potential of tick-borne agents remain poorly understood, there is a pressing need for microbial surveilla...
Data
Shotgun Sequencing Statistics. (XLSX)
Data
Taxonomic profiles of metagenomic sequences. (XLSX)
Data
SNP tables for Rm Nablus and CRt Nablus. (XLSX)
Data
Phylogenetic tree and SNP distance matrix showing Candidatus R. barbariae phylogenetically different from R. africae and R. parkeri. (PDF)
Data
16S rRNA sequence information. (XLSX)
Data
Biosample IDs and their corresponding tick names. (DOCX)
Data
Reference genomes for tick-borne pathogens and endosymbionts. (XLSX)
Data
Mapping coxiella endosymbiont R. sanguineus signature genes to CRs Tubas. (DOCX)
Data
Mitochondrial sequences of tick and host. (FASTA)
Data
Mapping of tick and host mitochondrial sequences. (DOCX)
Data
Mapping data for tick borne pathogens and endosymbionts. (DOCX)
Data
Multiple alignment of signature sequences confirming identity of Candidatus R. barbariae Rb Nablus. (ALN)
Article
Full-text available
Flagella, the primary means of motility in bacteria, are helical filaments that function as microscopic propellers composed of thousands of copies of the protein flagellin. Here, we show that many bacteria encode “giant” flagellins, greater than a thousand amino acids in length, and that two species that encode giant flagellins, the marine γ-proteo...
Data
Alignment of flagellar hook/hook-filament junction proteins (FlgE/FlgL) used to build our hidden Markov model for distinguishing between flagellins and hook/hook-filament function proteins. The file is a plain text file in ClustalX format that can be opened in any text editor for viewing. (CLUSTAL)
Data
Details of flagellins and strains used in the sequence analyses. (Tab 1) Details of all flagellins with >495 amino acids (the length of S. Typhimurium FliC) in the September 2017 release of UniProtKB. (Tab 2) Selected Oceanospiralles flagellins and species used to identify sequence homologies and repeats. (XLSX)
Data
Alignment of true flagellins used to build our hidden Markov model for distinguishing between flagellins and hook/hook-filament function proteins. The file is a plain text file in ClustalX format that can be opened in any text editor for viewing. (CLUSTAL)
Data
Swimming motility of Bermanella marisrubri Red65. Cells were grown for 24 h in 5 mL of Marine Broth 2216 (BD, New Jersey, U.S.A.) supplemented after autoclaving with 1% filter-sterilised Tween 80, within loosely-capped 30 mL sterile polystyrene universal tubes at 28°C and shaking at 200 rpm. A 5 μL sample was viewed using differential interference...
Data
Multiple sequence alignment of all Oceanospiralles Domain Extension regions that were found as tandem repeats. “ins” refers to the “insert” sequence, and “1half” and “2half” denotes either the first or second repeats. The file is a plain text file in ClustalX format that can be opened in any text editor for viewing. (FASTA_ALN)
Data
Full Mascot search results for peptides generated by tryptic digest of the 120 kDa SDS-PAGE band. Peptides were analysed by MALDI-TOF/TOF mass spectrometry. The top hits were to the expected Bermanella marisrubri giant flagellin. (CSV)
Data
Original Hidden Markov Model used to identify Domain Extension regions across the Oceanospiralles. This file is in the standard output format from the HMMER suite of programs for Hidden Markov Model-based sequence alignment, available at www.hmmer.org. (HMM)
Data
Swimming motility of Oleibacter marinus 2O1. Cells were grown for 24 h in 5 mL of Marine Broth 2216 (BD, New Jersey, U.S.A.) supplemented after autoclaving with 1% filter-sterilised Tween 80, within loosely-capped 30 mL sterile polystyrene universal tubes at 28°C and shaking at 200 rpm. A 5 μL sample was viewed using differential interference contr...
Data
Graphical logo representation of the Hidden Markov Model used to identify Domain Extension regions across the Oceanospiralles. (PNG)
Data
Pairwise alignment of the flagellin-containing contigs in our genome assembly and the reference assembly. (A) Overview of the whole alignment. (B) Detailed view of the alignment at the flagellin region (magenta box) showing 100% local identity. (C) Detailed view of the only sequence disagreement: an 84 bp intergenic region (olive box) present in th...
Data
Isolation and identification of the giant flagellin protein from Bermanella marisrubri Red65. (A) SDS-PAGE gel of proteins isolated from the surface of B. marisrubri by acid depolymerisation, as described in materials and methods. The arrow indicates the 120 kDa band that was cut out and used for identification by trypsin digestion and mass spectro...
Preprint
Flagella, the primary means of motility in bacteria, are helical filaments that function as microscopic propellers composed of thousands of copies of the protein flagellin. Here, we show that many bacteria encode “giant” flagellins, greater than a thousand amino acids in length, and that two species that encode giant flagellins, the marine γ- prote...
Article
Full-text available
Interdisciplinary scientific investigations utilising chemical analysis, shotgun metagenomics, textile analysis and radiocarbon dating have been applied to the study of an intact prehistoric Egyptian mummy, allowing insights into when this individual lived and died, and the funerary treatments employed in the preparation of the body. Here we presen...
Article
Full-text available
Nigeria has an emerging problem with multidrug-resistant tuberculosis (MDR-TB). Whole-genome sequencing was used to understand the epidemiology of tuberculosis and genetics of multi-drug resistance among patients from two tertiary referral centers in Southwest Nigeria. In line with previous molecular epidemiology studies, most isolates of Mycobacte...
Data
Isolates metadata. Metadata for study isolates including study site, age, sex, treatment status (study case), HIV status, MDR & pre-XDR status, as well as lineage information inferred from kvarq, phyressse (Phy) and TBProfiler (tbp). (XLSX)
Data
Isolate resistance profiles. Table showing phenotypic resistance profiles to first line drugs (rifampicin, isoniazid, streptomycin and ethambutol) for all isolates and to second line drugs (capreomycin, fluoroquinolone, ethionamide and amikacin) for MDR isolates. Table also lists presence of known resistance mutations as detected by the three resis...
Article
Full-text available
The chicken gastrointestinal tract is richly populated by commensal bacteria that fulfill various beneficial roles for the host, including helping to resist colonization by pathogens. It can also facilitate the conjugative transfer of multidrug resistance (MDR) plasmids between commensal and pathogenic bacteria which is a significant public and ani...