The role of bacteria in paralytic shellfish poisoning

Historically the production of paralytic shellfish toxins (PST), has been attributed to dinoflagellates. However, in the last decade, increasing evidence has been presented to indicate the involvement of a wide range of bacterial species including cyanobacteria and heterotrophic bacteria (Gallacher et al., 1997). Several studies investigating bacteria capable of PST production, have identified bacteria associated with dinoflagellates are capable of autonomous PST production (Gallacher et al., 1997). However, more recent research has focussed on the effects of these bacteria on toxin production by dinoflagellates, for which the production of bacterial-free (axenic) cultures is essential to identify whether dinoflagellates are capable of autonomous toxin production, in the absence of bacteria. Many different methods to produce axenic algal cultures have been published, including washing methods and the addition of bacteriolytic compounds. However, efforts to generate axenic dinoflagellate cultures, have been hampered not only by difficulties in removing associated bacteria, but also by the lack of effective methods for assessing the presence of certain bacteria. Traditionally, the absence of bacterial growth on marine media was considered acceptable proof for axenic status. However, as the numbers of bacteria determined by culture methods falls short of numbers detected using microscopy (Akagi et al., 1977), culture methods alone have been deemed inadequate to determine the axenic status of algal cultures. In this study, the production of an axenic dinoflagellate culture was vital, firstly, to assess the effect on dinoflagellate toxin production following removal of all associated bacteria, and secondly, to identify whether original toxicity was restored when the microflora was replaced. Methods to assess the axenic nature of cultures combined traditional methods of culturing, with epifluorescence microscopy, the method now frequently relied upon for axenic confirmation. However, molecular techniques were also included, which allowed the axenic status of dinoflagellate cultures to be confidently determined. The availability of molecular techniques also enabled an assessment of the bacterial diversity associated with original dinoflagellate cultures to be conducted, with culture-based and non culture-based identification systems adopted. This investigation indicated that a diverse range of bacteria were associated with cultures, although discrepancies between the two detection methods were noted. Results from the assessment of axenic dinoflagellate cultures confirmed the need for molecular methods, as bacterial DNA was identified in cultures which were considered axenic cultures using media assessment and epifluorescence microscopy. (Abstract shortened by ProQuest.)

Innate Immune Sensors and Gastrointestinal Bacterial Infections

The gastrointestinal microbiota is a major source of immune stimulation. The interaction between host pattern-recognition receptors and conserved microbial ligands profoundly influences infection dynamics. Identifying and understanding the nature of these interactions is a key step towards obtaining a clearer picture of microbial pathogenesis. These interactions underpin a complex interplay between microbe and host that has far reaching consequences for both. Here, we review the role of pattern recognition receptors in three prototype diseases affecting the stomach, the small intestine, and large intestine, respectively (Helicobacter pylori infection, Salmonella infection, and inflammatory bowel disease). Specifically, we review the nature and impact of pathogen:receptor interactions, their impact upon pathogenesis, and address the relevance of pattern recognition receptors in the development of therapies for gastrointestinal diseases

Detection of Campylobacter concisus and other Campylobacter species in colonic biopsies from adults with ulcerative colitis

Peer reviewedPublisher PD

Lack of association between the rs2294008 polymorphism in the prostate stem cell antigen gene and colorectal neoplasia : a case-control and immunohistochemical study

PMID: 22824379 [PubMed - indexed for MEDLINE] PMCID: PMC3500224 Free PMC ArticlePeer reviewedPublisher PD

The influence of early research experience in medical school on the decision to intercalate and future career in clinical academia : A questionnaire study

Funding for the study was made available from University academic development funds.Peer reviewedPublisher PD

The Effect of Vitamin D on Intestinal Inflammation and Faecal Microbiota in Patients with Ulcerative Colitis

This work was supported by the European Crohn’s and Colitis Organisation Fellowship awarded to Dr Mayur Garg, and St Mark’s Foundation Research Grant 2015 awarded to Prof Ailsa Hart and Dr Mayur Garg.Peer reviewedPostprin

Gut mucosal microbiome signatures of colorectal cancer differ according to BMI status

ACKNOWLEDGMENTS We gratefully acknowledge the NHS Grampian Biorepository for providing access to CRC patient samples and data. We thank members of the GI Research Team for discussions and advice. The authors thank Brennan Martin and the Centre for Genome Enabled Biology and Medicine for useful discussions.Peer reviewedPublisher PD

The gut virome:the ‘missing link’ between gut bacteria and host immunity?

The human gut virome includes a diverse collection of viruses that infect our own cells as well as other commensal organisms, directly impacting on our well-being. Despite its predominance, the virome remains one of the least understood components of the gut microbiota, with appropriate analysis toolkits still in development. Based on its interconnectivity with all living cells, it is clear that the virome cannot be studied in isolation. Here we review the current understanding of the human gut virome, specifically in relation to other constituents of the microbiome, its evolution and life-long association with its host, and our current understanding in the context of inflammatory bowel disease and associated therapies. We propose that the gut virome and the gut bacterial microbiome share similar trajectories and interact in both health and disease and that future microbiota studies should in parallel characterize the gut virome to uncover its role in health and disease

First-Pass Meconium Samples from Healthy Term Vaginally-Delivered Neonates : An Analysis of the Microbiota

Acknowledgments The authors would like to thank the parents who consented to provide samples with limited notice at an emotional and stressful time. This work was supported entirely from personal donations to the neonatal endowments fund at Aberdeen Maternity Hospital and we thank families for their continued generosity, year-on-year. The Rowett Institute of Nutrition and Health receives funding from the Scottish Government (SG-RESAS). Funding: This work was funded from NHS Grampian Neonatal Endowments. The Rowett Institute receives funding from the Rural and Environmental Science and Analytical Services programme of the Scottish Government. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Innate immune sensors and gastrointestinal bacterial infections.

The gastrointestinal microbiota is a major source of immune stimulation. The interaction between host pattern-recognition receptors and conserved microbial ligands profoundly influences infection dynamics. Identifying and understanding the nature of these interactions is a key step towards obtaining a clearer picture of microbial pathogenesis. These interactions underpin a complex interplay between microbe and host that has far reaching consequences for both. Here, we review the role of pattern recognition receptors in three prototype diseases affecting the stomach, the small intestine, and large intestine, respectively (Helicobacter pylori infection, Salmonella infection, and inflammatory bowel disease). Specifically, we review the nature and impact of pathogen:receptor interactions, their impact upon pathogenesis, and address the relevance of pattern recognition receptors in the development of therapies for gastrointestinal diseases.Peer Reviewe