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1.
Microb Genom ; 10(6)2024 Jun.
Article in English | MEDLINE | ID: mdl-38847800

ABSTRACT

Sequence comparison of 16S rRNA PCR amplicons is an established approach to taxonomically identify bacterial isolates and profile complex microbial communities. One potential application of recent advances in long-read sequencing technologies is to sequence entire rRNA operons and capture significantly more phylogenetic information compared to sequencing of the 16S rRNA (or regions thereof) alone, with the potential to increase the proportion of amplicons that can be reliably classified to lower taxonomic ranks. Here we describe GROND (Genome-derived Ribosomal Operon Database), a publicly available database of quality-checked 16S-ITS-23S rRNA operons, accompanied by multiple taxonomic classifications. GROND will aid researchers in analysis of their data and act as a standardised database to allow comparison of results between studies.


Subject(s)
Bacteria , Phylogeny , RNA, Ribosomal, 16S , RNA, Ribosomal, 16S/genetics , Bacteria/genetics , Bacteria/classification , RNA, Ribosomal, 23S/genetics , Operon , rRNA Operon/genetics , Databases, Genetic , Databases, Nucleic Acid , Sequence Analysis, DNA/methods
2.
J Food Sci ; 89(2): 773-792, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38174642

ABSTRACT

A systematic approach to collect, peruse, and summarize the available information relating to the potential benefits of consuming dietary microbes was pursued in this scoping review. This review focused on the research endpoints, experimental designs, and microbial exposure in experimental as well as observational research work. Using a structured- set of keywords, scientific databases were systematically searched to retrieve publications reporting outcomes pertaining to the use of dietary microbes in healthy, nonpatient populations. Searches were further tailored to focus on eight different health categories, namely, "antibiotic associated diarrhoea" (AAD), "gastrointestinal health" (GIH), "immunological health" (ImH), "cardiovascular health and metabolic syndrome" (CvHMS), "cancer prevention" (CanPr), "respiratory health" (ReH), "weight management" (WtMgt), and "urogenital health" (UrGH). Quality of evidence available in each publication was assessed using the Jadad scoring system. The search yielded 228 relevant publications describing 282 experimental cases comprising 62 research endpoints overall. A microbial dose of ≥ 2 × 10 9 $\ge 2\times 10^9$ CFU.day-1 was associated with non-negative reported outcomes. Older population groups with a median age of 39 years were associated with positive outcomes. More high-quality research is required investigating the role of dietary microbes in maintaining general health, particularly in the health categories of UrGH, WtMgt, and CanPr.


Subject(s)
Diet , Metabolic Syndrome , Humans , Adult , Diarrhea , Gastrointestinal Tract , Anti-Bacterial Agents
3.
BMJ Open ; 13(5): e067766, 2023 05 17.
Article in English | MEDLINE | ID: mdl-37197820

ABSTRACT

INTRODUCTION: It has been hypothesised that the regular consumption of safe, live microbes confers health-promoting attributes, including the prevention of disease. To address this hypothesis, we propose a scoping review approach that will systematically assess the large corpus of relevant literature that is now available on this research topic. This article outlines a protocol for a scoping review of published studies on interventions with live microbes in non-patient populations across eight health categories. The scoping review aims to catalogue types of interventions, measured outcomes, dosages, effectiveness, as well as current research gaps. METHODS AND ANALYSIS: The scoping review will follow the six-staged protocol as proposed by Arksey and O'Malley and will include the following stages: defining the research questions (stage 1); defining the eligibility criteria and finalising search strategy (stage 2); selection of studies based on the eligibility criteria (stage 3); development of a data extraction framework and charting of data (stage 4); aggregation of results and summarisation of findings (stage 5); and the optional consultation with stakeholders (stage 6), which will not be performed. ETHICS AND DISSEMINATION: Since the scoping review synthesises information from existing literature, no separate ethical approval is required. The findings of the scoping review will be communicated for publication to an open-access, peer-reviewed scientific journal, presented at relevant conferences, and disseminated at future workshops with all relevant data and documents being available online through the Open Science Framework (https://osf.io/kvhe7).


Subject(s)
Research Design , Review Literature as Topic , Humans
4.
Rheumatology (Oxford) ; 62(SI2): SI210-SI225, 2023 02 23.
Article in English | MEDLINE | ID: mdl-35532072

ABSTRACT

OBJECTIVES: Juvenile-onset systemic lupus erythematosus (jSLE) affects 15-20% of lupus patients. Clinical heterogeneity between racial groups, age groups and individual patients suggests variable pathophysiology. This study aimed to identify highly penetrant damaging mutations in genes associated with SLE/SLE-like disease in a large national cohort (UK JSLE Cohort Study) and compare demographic, clinical and laboratory features in patient sub-cohorts with 'genetic' SLE vs remaining SLE patients. METHODS: Based on a sequencing panel designed in 2018, target enrichment and next-generation sequencing were performed in 348 patients to identify damaging gene variants. Findings were integrated with demographic, clinical and treatment related datasets. RESULTS: Damaging gene variants were identified in ∼3.5% of jSLE patients. When compared with the remaining cohort, 'genetic' SLE affected younger children and more Black African/Caribbean patients. 'Genetic' SLE patients exhibited less organ involvement and damage, and neuropsychiatric involvement developed over time. Less aggressive first line treatment was chosen in 'genetic' SLE patients, but more second and third line agents were used. 'Genetic' SLE associated with anti-dsDNA antibody positivity at diagnosis and reduced ANA, anti-LA and anti-Sm antibody positivity at last visit. CONCLUSION: Approximately 3.5% of jSLE patients present damaging gene variants associated with younger age at onset, and distinct clinical features. As less commonly observed after treatment induction, in 'genetic' SLE, autoantibody positivity may be the result of tissue damage and explain reduced immune complex-mediated renal and haematological involvement. Routine sequencing could allow for patient stratification, risk assessment and target-directed treatment, thereby increasing efficacy and reducing toxicity.


Subject(s)
Lupus Erythematosus, Systemic , Humans , Cohort Studies , Age of Onset , Lupus Erythematosus, Systemic/complications , Kidney , Phenotype
5.
Viruses ; 14(9)2022 09 09.
Article in English | MEDLINE | ID: mdl-36146802

ABSTRACT

Bacterial infections of livestock threaten the sustainability of agriculture and public health through production losses and contamination of food products. While prophylactic and therapeutic application of antibiotics has been successful in managing such infections, the evolution and spread of antibiotic-resistant strains along the food chain and in the environment necessitates the development of alternative or adjunct preventive and/or therapeutic strategies. Additionally, the growing consumer preference for "greener" antibiotic-free food products has reinforced the need for novel and safer approaches to controlling bacterial infections. The use of bacteriophages (phages), which can target and kill bacteria, are increasingly considered as a suitable measure to reduce bacterial infections and contamination in the food industry. This review primarily elaborates on the recent veterinary applications of phages and discusses their merits and limitations. Furthermore, using Streptococcus suis as a model, we describe the prevalence of prophages and the anti-viral defence arsenal in the genome of the pathogen as a means to define the genetic building blocks that are available for the (synthetic) development of phage-based treatments. The data and approach described herein may provide a framework for the development of therapeutics against an array of bacterial pathogens.


Subject(s)
Bacterial Infections , Bacteriophages , Streptococcus suis , Anti-Bacterial Agents/therapeutic use , Bacteria , Bacterial Infections/therapy , Bacteriophages/genetics , Farms , Humans , Prophages/genetics , Streptococcus suis/genetics
6.
Front Nutr ; 9: 902642, 2022.
Article in English | MEDLINE | ID: mdl-35719144

ABSTRACT

In recent years, there has been a global resurgence of public interest in fermented foods. In parallel, there have been several new studies that associate the consumption of fermented foods with a variety of beneficial impacts. These combined developments have led to a renewed focus in research and innovation vis-à-vis fermented foods, particularly traditional fermented foods, with an aim to harness this information to develop novel fermented foodstuffs and ingredients and make them available in the market. Consequently, an ever greater and more diverse array of fermented foods, including functional fermented foods with health benefits, are becoming available for public consumption in global markets, with the number expected to grow substantially in the coming decade. This rapidly expanding portfolio of commercially available fermented foods has in turn required an evolution in the corresponding global regulatory frameworks. Due to the innovative and emerging nature of these foods, combined with historical differences in regulator approaches, significant disharmony exists across these frameworks, with individual nations and organizations often adopting unique approaches relating to the establishment of standards and specifications. In this review, we provide an overview of the current regulatory frameworks for a diversity of fermented foods across multiple jurisdictions, with special emphasis on differences in legislative structures and approaches, regulatory harmonization, and current legislative limitations. Overall, the review provides important perspective and context in relation to current global fermented food regulatory practices with possible directions and recommendations for future legislative efforts.

7.
Foods ; 11(20)2022 Oct 21.
Article in English | MEDLINE | ID: mdl-37431045

ABSTRACT

The microbial communities present within fermented foods are diverse and dynamic, producing a variety of metabolites responsible for the fermentation processes, imparting characteristic organoleptic qualities and health-promoting traits, and maintaining microbiological safety of fermented foods. In this context, it is crucial to study these microbial communities to characterise fermented foods and the production processes involved. High Throughput Sequencing (HTS)-based methods such as metagenomics enable microbial community studies through amplicon and shotgun sequencing approaches. As the field constantly develops, sequencing technologies are becoming more accessible, affordable and accurate with a further shift from short read to long read sequencing being observed. Metagenomics is enjoying wide-spread application in fermented food studies and in recent years is also being employed in concert with synthetic biology techniques to help tackle problems with the large amounts of waste generated in the food sector. This review presents an introduction to current sequencing technologies and the benefits of their application in fermented foods.

8.
Gut Microbes ; 13(1): 1930871, 2021.
Article in English | MEDLINE | ID: mdl-34241567

ABSTRACT

The etiology of Crohn's disease (CD) is multifactorial. Bacterial and fungal microbiota are involved in the onset and/or progression of the disease. A bacterial dysbiosis in CD patients is accepted; however, less is known about the mycobiome and the relationships between the two communities. We investigated the interkingdom relationships, their metabolic consequences, and the changes in the fungal community during relapse and remission in CD.Two cohorts were evaluated: a British cohort (n = 63) comprising CD and ulcerative colitis patients, and controls. The fungal and bacterial communities of biopsy and fecal samples were analyzed, with the fecal volatiles; datasets were also integrated; and a Dutch cohort (n = 41) comprising CD patients and healthy controls was analyzed for stability of the gut mycobiome.A dysbiosis of the bacterial community was observed in biopsies and stool. Results suggest Bacteroides is likely key in CD and may modulate Candida colonization. A dysbiosis of the fungal community was observed only in the Dutch cohort; Malassezia and Candida were increased in patients taking immunosuppressants. Longitudinal analysis showed an increase in Cyberlindnera in relapse. Saccharomyces was dominant in all fecal samples, but not in biopsies, some of which did not yield fungal reads; amino acid degradation was the main metabolic change associated with CD and both bacteria and fungi might be implicated.We have shown that Bacteroides and yeasts may play a role in CD; understanding their role and relationship in the disease would shed new light on the development and treatment of CD.


Subject(s)
Bacteria/isolation & purification , Crohn Disease/microbiology , Fungi/isolation & purification , Gastrointestinal Microbiome , Adolescent , Adult , Aged , Bacteria/classification , Bacteria/genetics , Child , Cohort Studies , Dysbiosis/microbiology , Feces/microbiology , Female , Fungi/classification , Fungi/genetics , Humans , Male , Middle Aged , Young Adult
9.
Sci Rep ; 11(1): 4565, 2021 02 25.
Article in English | MEDLINE | ID: mdl-33633172

ABSTRACT

Alterations in the human microbiome have been observed in a variety of conditions such as asthma, gingivitis, dermatitis and cancer, and much remains to be learned about the links between the microbiome and human health. The fusion of artificial intelligence with rich microbiome datasets can offer an improved understanding of the microbiome's role in human health. To gain actionable insights it is essential to consider both the predictive power and the transparency of the models by providing explanations for the predictions. We combine the collection of leg skin microbiome samples from two healthy cohorts of women with the application of an explainable artificial intelligence (EAI) approach that provides accurate predictions of phenotypes with explanations. The explanations are expressed in terms of variations in the relative abundance of key microbes that drive the predictions. We predict skin hydration, subject's age, pre/post-menopausal status and smoking status from the leg skin microbiome. The changes in microbial composition linked to skin hydration can accelerate the development of personalized treatments for healthy skin, while those associated with age may offer insights into the skin aging process. The leg microbiome signatures associated with smoking and menopausal status are consistent with previous findings from oral/respiratory tract microbiomes and vaginal/gut microbiomes respectively. This suggests that easily accessible microbiome samples could be used to investigate health-related phenotypes, offering potential for non-invasive diagnosis and condition monitoring. Our EAI approach sets the stage for new work focused on understanding the complex relationships between microbial communities and phenotypes. Our approach can be applied to predict any condition from microbiome samples and has the potential to accelerate the development of microbiome-based personalized therapeutics and non-invasive diagnostics.


Subject(s)
Artificial Intelligence , Biodiversity , Microbiota , Phenotype , Skin/microbiology , Adult , Aged , Aging , Computational Biology/methods , Data Analysis , Deep Learning , Female , Humans , Male , Menopause , Metagenome , Metagenomics/methods , Middle Aged , Smokers , Young Adult
10.
Cancers (Basel) ; 12(4)2020 Apr 23.
Article in English | MEDLINE | ID: mdl-32340176

ABSTRACT

Uveal melanoma (UM) has well-characterised somatic copy number alterations (SCNA) in chromosomes 1, 3, 6 and 8, in addition to mutations in GNAQ, GNA11, CYSLTR2, PLCB4, BAP1, SF3B1 and EIF1AX, most being linked to metastatic-risk. To gain further insight into the molecular landscape of UM, we designed a targeted next-generation sequencing (NGS) panel to detect SCNA and mutations in routine clinical UM samples. We compared hybrid-capture and amplicon-based target enrichment methods and tested a larger cohort of primary UM samples on the best performing panel. UM clinical samples processed either as fresh-frozen, formalin-fixed paraffin embedded (FFPE), small intraocular biopsies or following irradiation were successfully profiled using NGS, with hybrid capture outperforming the PCR-based enrichment methodology. We identified monosomy 3 (M3)-UM that were wild-type for BAP1 but harbored SF3B1 mutations, novel frameshift deletions in SF3B1 and EIF1AX, as well as a PLCB4 mutation outside of the hotspot on exon 20 coinciding with a GNAQ mutation in some UM. We observed samples that harboured mutations in both BAP1 and SF3B1, and SF3B1 and EIF1AX, respectively. Novel mutations were also identified in TTC28, KTN1, CSMD1 and TP53BP1. NGS can simultaneously assess SCNA and mutation data in UM, in a reliable and reproducible way, irrespective of sample type or previous processing. BAP1 and SF3B1 mutations, in addition to 8q copy number, are of added importance when determining UM patient outcome.

11.
Sci Rep ; 9(1): 9328, 2019 06 27.
Article in English | MEDLINE | ID: mdl-31249384

ABSTRACT

Microbial ecology studies are often performed through extraction of metagenomic DNA followed by amplification and sequencing of a marker. It is known that each step may bias the results. These biases have been explored for the study of bacterial communities, but rarely for fungi. Our aim was therefore to evaluate methods for the study of the gut mycobiome. We first evaluated DNA extraction methods in fungal cultures relevant to the gut. Afterwards, to assess how these methods would behave with an actual sample, stool from a donor was spiked with cells from the same cultures. We found that different extraction kits favour some species and bias against others. In terms of amplicon sequencing, we evaluated five primer sets, two for ITS2 and one for ITS1, 18S and 28S rRNA. Results showed that 18S rRNA outperformed the other markers: it was able to amplify all the species in the mock community and to discriminate among them. ITS primers showed both amplification and sequencing biases, the latter related to the variable length of the product. We identified several biases in the characterisation of the gut mycobiome and showed how crucial it is to be aware of these before drawing conclusions from the results of these studies.


Subject(s)
DNA, Fungal/isolation & purification , Gastrointestinal Microbiome/genetics , DNA Primers/genetics , DNA, Fungal/genetics , Feces/microbiology , Humans , RNA, Ribosomal, 18S/genetics
12.
Nat Commun ; 10(1): 1107, 2019 03 07.
Article in English | MEDLINE | ID: mdl-30846683

ABSTRACT

Soil biota accounts for ~25% of global biodiversity and is vital to nutrient cycling and primary production. There is growing momentum to study total belowground biodiversity across large ecological scales to understand how habitat and soil properties shape belowground communities. Microbial and animal components of belowground communities follow divergent responses to soil properties and land use intensification; however, it is unclear whether this extends across heterogeneous ecosystems. Here, a national-scale metabarcoding analysis of 436 locations across 7 different temperate ecosystems shows that belowground animal and microbial (bacteria, archaea, fungi, and protists) richness follow divergent trends, whereas ß-diversity does not. Animal richness is governed by intensive land use and unaffected by soil properties, while microbial richness was driven by environmental properties across land uses. Our findings demonstrate that established divergent patterns of belowground microbial and animal diversity are consistent across heterogeneous land uses and are detectable using a standardised metabarcoding approach.


Subject(s)
Biodiversity , Ecosystem , Soil Microbiology , Soil , Animals , Computational Biology , DNA Barcoding, Taxonomic , Microbiota/genetics , Wales
13.
J Invest Dermatol ; 139(1): 100-107, 2019 01.
Article in English | MEDLINE | ID: mdl-30030151

ABSTRACT

Biologic therapies have shown high efficacy in psoriasis, but individual response varies and is poorly understood. To inform biomarker discovery in the Psoriasis Stratification to Optimise Relevant Therapy (i.e., PSORT) study, we evaluated a comprehensive array of omics platforms across three time points and multiple tissues in a pilot investigation of 10 patients with severe psoriasis, treated with the tumor necrosis factor (TNF) inhibitor, etanercept. We used RNA sequencing to analyze mRNA and small RNA transcriptome in blood, lesional and nonlesional skin, and the SOMAscan platform to investigate the serum proteome. Using an integrative systems biology approach, we identified signals of treatment response in genes and pathways associated with TNF signaling, psoriasis pathology, and the major histocompatibility complex region. We found association between clinical response and TNF-regulated genes in blood and skin. Using a combination of differential expression testing, upstream regulator analysis, clustering techniques, and predictive modeling, we show that baseline samples are indicative of patient response to biologic therapies, including signals in blood, which have traditionally been considered unreliable for inference in dermatology. In conclusion, our pilot study provides both an analytical framework and empirical basis to estimate power for larger studies, specifically the ongoing PSORT study, which we show as powered for biomarker discovery and patient stratification.


Subject(s)
Biological Therapy/methods , Etanercept/therapeutic use , Gene Expression Regulation , Psoriasis/drug therapy , RNA, Messenger/genetics , Adult , Female , Follow-Up Studies , Humans , Immunosuppressive Agents/therapeutic use , Male , Pilot Projects , Prognosis , Prospective Studies , Psoriasis/genetics , Psoriasis/metabolism , Skin
14.
ISME J ; 12(2): 386-399, 2018 02.
Article in English | MEDLINE | ID: mdl-29028005

ABSTRACT

Decline-diseases are complex and becoming increasingly problematic to tree health globally. Acute Oak Decline (AOD) is characterized by necrotic stem lesions and galleries of the bark-boring beetle, Agrilus biguttatus, and represents a serious threat to oak. Although multiple novel bacterial species and Agrilus galleries are associated with AOD lesions, the causative agent(s) are unknown. The AOD pathosystem therefore provides an ideal model for a systems-based research approach to address our hypothesis that AOD lesions are caused by a polymicrobial complex. Here we show that three bacterial species, Brenneria goodwinii, Gibbsiella quercinecans and Rahnella victoriana, are consistently abundant in the lesion microbiome and possess virulence genes used by canonical phytopathogens that are expressed in AOD lesions. Individual and polyspecies inoculations on oak logs and trees demonstrated that B. goodwinii and G. quercinecans cause tissue necrosis and, in combination with A. biguttatus, produce the diagnostic symptoms of AOD. We have proved a polybacterial cause of AOD lesions, providing new insights into polymicrobial interactions and tree disease. This work presents a novel conceptual and methodological template for adapting Koch's postulates to address the role of microbial communities in disease.


Subject(s)
Coleoptera/microbiology , Enterobacteriaceae/genetics , Microbiota , Plant Diseases/microbiology , Quercus/microbiology , Rahnella/genetics , Algorithms , Animals , Enterobacteriaceae/pathogenicity , Genome, Bacterial , Genome, Plant , Metagenome , Necrosis , Phylogeny , Rahnella/pathogenicity , Systems Biology , Transcriptome
15.
Biotechniques ; 63(1): 13-20, 2017 07 01.
Article in English | MEDLINE | ID: mdl-28701143

ABSTRACT

Current DNA assembly methods are prone to sequence errors, requiring rigorous quality control (QC) to identify incorrect assemblies or synthesized constructs. Such errors can lead to misinterpretation of phenotypes. Because of this intrinsic problem, routine QC analysis is generally performed on three or more clones using a combination of restriction endonuclease assays, colony PCR, and Sanger sequencing. However, as new automation methods emerge that enable high-throughput assembly, QC using these techniques has become a major bottleneck. Here, we describe a quick and affordable methodology for the QC of synthetic constructs. Our method involves a one-pot digestion-ligation DNA assembly reaction, based on the Golden Gate assembly methodology, that is coupled with Pacific Biosciences' Single Molecule, Real-Time (PacBio SMRT) sequencing technology.


Subject(s)
Databases, Genetic , Sequence Analysis, DNA/methods , Base Sequence , Quality Control
16.
BMC Genomics ; 17: 55, 2016 Jan 14.
Article in English | MEDLINE | ID: mdl-26763898

ABSTRACT

BACKGROUND: In the last 5 years, the rapid pace of innovations and improvements in sequencing technologies has completely changed the landscape of metagenomic and metagenetic experiments. Therefore, it is critical to benchmark the various methodologies for interrogating the composition of microbial communities, so that we can assess their strengths and limitations. The most common phylogenetic marker for microbial community diversity studies is the 16S ribosomal RNA gene and in the last 10 years the field has moved from sequencing a small number of amplicons and samples to more complex studies where thousands of samples and multiple different gene regions are interrogated. RESULTS: We assembled 2 synthetic communities with an even (EM) and uneven (UM) distribution of archaeal and bacterial strains and species, as metagenomic control material, to assess performance of different experimental strategies. The 2 synthetic communities were used in this study, to highlight the limitations and the advantages of the leading sequencing platforms: MiSeq (Illumina), The Pacific Biosciences RSII, 454 GS-FLX/+ (Roche), and IonTorrent (Life Technologies). We describe an extensive survey based on synthetic communities using 3 experimental designs (fusion primers, universal tailed tag, ligated adaptors) across the 9 hypervariable 16S rDNA regions. We demonstrate that library preparation methodology can affect data interpretation due to different error and chimera rates generated during the procedure. The observed community composition was always biased, to a degree that depended on the platform, sequenced region and primer choice. However, crucially, our analysis suggests that 16S rRNA sequencing is still quantitative, in that relative changes in abundance of taxa between samples can be recovered, despite these biases. CONCLUSION: We have assessed a range of experimental conditions across several next generation sequencing platforms using the most up-to-date configurations. We propose that the choice of sequencing platform and experimental design needs to be taken into consideration in the early stage of a project by running a small trial consisting of several hypervariable regions to quantify the discriminatory power of each region. We also suggest that the use of a synthetic community as a positive control would be beneficial to identify the potential biases and procedural drawbacks that may lead to data misinterpretation. The results of this study will serve as a guideline for making decisions on which experimental condition and sequencing platform to consider to achieve the best microbial profiling.


Subject(s)
Genome, Bacterial , High-Throughput Nucleotide Sequencing/methods , Metagenomics , RNA, Ribosomal, 16S/genetics , Bacteria/genetics , Benchmarking , Phylogeny , RNA, Ribosomal, 16S/classification
17.
Appl Environ Microbiol ; 81(23): 8118-25, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26386055

ABSTRACT

Shiga-toxigenic bacteriophages are converting lambdoid phages that impart the ability to produce Shiga toxin to their hosts. Little is known about the function of most of the genes carried by these phages or the impact that lysogeny has on the Escherichia coli host. Here we use next-generation sequencing to compare the transcriptomes of E. coli strains infected with an Stx phage, before and after triggering of the bacterial SOS response that initiates the lytic cycle of the phage. We were able to discriminate between bacteriophage genes expressed in the lysogenic and lytic cycles, and we describe transcriptional changes that occur in the bacterial host as a consequence of Stx phage carriage. Having identified upregulation of the glutamic acid decarboxylase (GAD) operon, confirmed by reverse transcription-quantitative PCR (RT-qPCR), we used phenotypic assays to establish the ability of the Stx prophage to confer a greater acid resistance phenotype on the E. coli host. Known phage regulators were overexpressed in E. coli, and the acid resistance of the recombinant strains was tested. The phage-encoded transcriptional regulator CII was identified as the controller of the acid response in the lysogen. Infection of an E. coli O157 strain, from which integrated Stx prophages were previously removed, showed increased acid resistance following infection with a nontoxigenic phage, ϕ24B. In addition to demonstrating this link between Stx phage carriage and E. coli acid resistance, with its implications for survival postingestion, the data set provides a number of other potential insights into the impact of lambdoid phage carriage on the biology of E. coli.


Subject(s)
Bacteriophages/genetics , Escherichia coli O157/metabolism , Escherichia coli O157/virology , Prophages/genetics , Transcriptome , Viral Proteins/genetics , Bacteriophages/metabolism , Escherichia coli O157/genetics , Gene Expression Profiling , Prophages/metabolism , Sequence Analysis, RNA , Viral Proteins/metabolism
18.
Mol Biol Evol ; 32(4): 888-95, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25534027

ABSTRACT

Epigenetic marks such as DNA methylation play important biological roles in gene expression regulation and cellular differentiation during development. To examine whether DNA methylation patterns are potentially associated with naturally occurring phenotypic differences, we examined genome-wide DNA methylation within Gasterosteus aculeatus, using reduced representation bisulfite sequencing. First, we identified highly methylated regions of the stickleback genome, finding such regions to be located predominantly within genes, and associated with genes functioning in metabolism and biosynthetic processes, cell adhesion, signaling pathways, and blood vessel development. Next, we identified putative differentially methylated regions (DMRs) of the genome between complete and low lateral plate morphs of G. aculeatus. We detected 77 DMRs that were mainly located in intergenic regions. Annotations of genes associated with these DMRs revealed potential functions in a number of known divergent adaptive phenotypes between G. aculeatus ecotypes, including cardiovascular development, growth, and neuromuscular development.


Subject(s)
DNA Methylation , Genome , Phenotype , Smegmamorpha/genetics , Animals , Base Sequence , Cell Adhesion/genetics , Female , Genes , Growth and Development/genetics , Metabolic Networks and Pathways/genetics , Molecular Sequence Data , Signal Transduction/genetics
19.
Mol Ecol ; 23(21): 5179-92, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25244680

ABSTRACT

The evolution of diversity in the marine ecosystem is poorly understood, given the relatively high potential for connectivity, especially for highly mobile species such as whales and dolphins. The killer whale (Orcinus orca) has a worldwide distribution, and individual social groups travel over a wide geographic range. Even so, regional populations have been shown to be genetically differentiated, including among different foraging specialists (ecotypes) in sympatry. Given the strong matrifocal social structure of this species together with strong resource specializations, understanding the process of differentiation will require an understanding of the relative importance of both genetic drift and local adaptation. Here we provide a high-resolution analysis based on nuclear single-nucleotide polymorphic markers and inference about differentiation at both neutral loci and those potentially under selection. We find that all population comparisons, within or among foraging ecotypes, show significant differentiation, including populations in parapatry and sympatry. Loci putatively under selection show a different pattern of structure compared to neutral loci and are associated with gene ontology terms reflecting physiologically relevant functions (e.g. related to digestion). The pattern of differentiation for one ecotype in the North Pacific suggests local adaptation and shows some fixed differences among sympatric ecotypes. We suggest that differential habitat use and resource specializations have promoted sufficient isolation to allow differential evolution at neutral and functional loci, but that the process is recent and dependent on both selection and drift.


Subject(s)
Ecotype , Genetic Drift , Selection, Genetic , Sympatry , Whale, Killer/genetics , Animals , Evolution, Molecular , Genetic Loci , Genetics, Population , Molecular Sequence Data , Polymorphism, Single Nucleotide , Sequence Analysis, DNA
20.
PLoS One ; 8(7): e67698, 2013.
Article in English | MEDLINE | ID: mdl-23861785

ABSTRACT

Mannitol (Mtl) fermentation, with the subsequent production of acid, is a species signature of Staphylococcus aureus, and discriminates it from most other members of the genus. Inactivation of the gene mtlD, encoding Mtl-1-P dehydrogenase was found to markedly reduce survival in the presence of the antimicrobial fatty acid, linoleic acid. We demonstrate that the sugar alcohol has a potentiating action for this membrane-acting antimicrobial. Analysis of cellular metabolites revealed that, during exponential growth, the mtlD mutant accumulated high levels of Mtl and Mtl-P. The latter metabolite was not detected in its isogenic parent strain or a deletion mutant of the entire mtlABFD operon. In addition, the mtlD mutant strain exhibited a decreased MIC for H2O2, however virulence was unaffected in a model of septic arthritis.


Subject(s)
Bacterial Proteins/genetics , Gene Expression Regulation, Bacterial , Mannitol/metabolism , Skin/microbiology , Staphylococcus aureus/metabolism , Sugar Alcohol Dehydrogenases/genetics , Animals , Bacterial Proteins/metabolism , Humans , Hydrogen Peroxide/pharmacology , Linoleic Acid/pharmacology , Mice , Microbial Sensitivity Tests , Microbial Viability/drug effects , Mutation , Operon , Staphylococcal Skin Infections/microbiology , Staphylococcus aureus/genetics , Staphylococcus aureus/growth & development , Sugar Alcohol Dehydrogenases/deficiency , Virulence
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