Dr Karen Scott


Dr Karen Scott

Investigations into the metabolism of different substrates by gut bacteria

The human large intestine is home to the largest and most diverse group of bacteria in the human body. These bacteria play an important role in maintaining human health, fermenting plant fibres and other non-digestible carbohydrates, and releasing compounds that have direct or indirect benefits to human health.

We are interested in investigating the interactions between different bacterial groups, how populations and bacterial activities change through life, and how they respond to the availability of specific growth substrates.

Understanding the impact of specific dietary components on gut bacteria will help us to formulate health advice for the general population.

Scottish grains and ancient varieties video

FHIS Science Bytes video

The microbial community in the human large intestine consists of a diverse range of bacteria that are predominantly obligate anaerobes.  One approach utilised a differential expression technique combined with microarrray analysis to investigate gene expression in Roseburia inulinivorans. We have successfully reintroduced some of these bacteria in a simulated human colon system against a background of total colonic microbiota. Thus there is a real potential for manipulating the balance of the gut microbiota improve health both by prebiotic and probiotic approaches. However we first need to improve our knowledge of the composition of the normal microbiota. This has been done in my work using new techniques targeting the 16S rDNA gene to enumerate numbers of specific bacterial groups using both fluorescent in situ hybridisation (FISH) and pyrosequencing.

My research also aims to determine key substrates that are the preferred energy source of specific beneficial gut bacteria, and identify the genes involved in their metabolism. One approach utilised a differential expression technique combined with microarrray analysis. The microarray approach successfully identified a novel fucose utilisation pathway, a novel mechanism for the utilisation of long chain inulin for growth, and was also used to identify genes involved in the interactions between bacteria, and between bacteria and the human host.

The information from these studies can ultimately be used to develop new pro/pre/synbiotic approaches to manipulate the gut flora with the aim of improving human health. A related research interest is gene transfer between gut bacteria, specifically the transfer of antibiotic resistance genes. These genes provide a model for the spread of genetic information between bacteria in an ecosystem, and between ecosystems, and illustrates the high frequency with which gene transfer events occur between bacteria.

Research team

Ms Jenny Martin - Research Assistant

Factors influencing transgene survival and transfer in the rumen. Grant holders – Karen Scott (RINH) and Jamie Newbold (University of Aberystwyth). Funded by the FSA.

  • Sheridan, PO., Martin, JC., Lawley, TD., Browne, HP., Harris, H., Bernalier-Donadille, A., Duncan, SH., O'Toole, PW., Scott, KP. & Flint, HJ. (2016). 'Polysaccharide utilization loci and nutritional specialization in a dominant group of butyrate-producing human colonic Firmicutes'. Microbial Genomics, vol 2, no. 2, 43.
    [Online] DOI: 10.1099/mgen.0.000043
    [Online] AURA: mgen000043.pdf
  • Walker, AW., Martin, JC., Scott, P., Parkhill, J., Flint, HJ. & Scott, KP. (2015). '16S rRNA gene-based profiling of the human infant gut microbiota is strongly influenced by sample processing and PCR primer choice'. Microbiome, vol 3, 26.
    [Online] DOI: 10.1186/s40168-015-0087-4
    [Online] AURA: Infant_Bifids_Protocols_Microbiome2015.pdf
    [Link] http://www.microbiomejournal.com/content/3/1/26
  • Hansen, R., Scott, KP., Khan, S., Martin, JC., Berry, SH., Stevenson, M., Okpapi, A., Munro, MJ. & Hold, GL. (2015). 'First-Pass Meconium Samples from Healthy Term Vaginally-Delivered Neonates: An Analysis of the Microbiota'. PloS one, vol 10, no. 7, e0133320.
    [Online] DOI: 10.1371/journal.pone.0133320
    [Online] AURA: journal.pone.0133320.pdf
  • Scott, KP., Martin, JC., Duncan, SH. & Flint, HJ. (2014). 'Prebiotic stimulation of human colonic butyrate-producing bacteria and bifidobacteria, in vitro'. FEMS Microbiology Ecology, vol 87, no. 1, pp. 30-40.
    [Online] DOI: 10.1111/1574-6941.12186
  • Reichardt, N., Duncan, SH., Young, P., Belenguer, A., McWilliam Leitch, C., Scott, KP., Flint, HJ. & Louis, P. (2014). 'Phylogenetic distribution of three pathways for propionate production within the human gut microbiota'. The ISME Journal, vol 8, no. 6, pp. 1323-1335.
    [Online] DOI: 10.1038/ismej.2014.14
  • Neville, BA., Sheridan, PO., Harris, HMB., Coughlan, S., Flint, HJ., Duncan, SH., Jeffery, IB., Claesson, MJ., Ross, RP., Scott, KP. & O'Toole, PW. (2013). 'Pro-inflammatory flagellin proteins of prevalent motile commensal bacteria are variably abundant in the intestinal microbiome of elderly humans'. PLoS ONE, vol 8, no. 7, e68919.
    [Online] DOI: 10.1371/journal.pone.0068919
    [Online] AURA: Pro_inflammatory_flagellin.pdf

Research briefs for the Knowledge Scotland web site

Additional Responsibilities

Treasurer of the International Scientific Association for Probiotics and Prebiotics (ISAPP).