• Comparative genomics and gene-trait matching analysis of Bifidobacterium breve from Chinese children

      Liu, Rui; Yang, Bo; STANTON, CATHERINE; Ross, Paul; Zhao, Jianxin; Zhang, Hao; Chen, Wei; National Natural Science Foundation of China; National First-Class Discipline Program of Food Science and Technology; the Fundamental Research Funds for the Central Universities; et al. (Elsevier BV, 2020-08)
      Bifidobacterium breve is one of the dominant Bifidobacterial species in children. In the current work, 46 strains of B. breve isolated from fecal samples of Chinese children were analyzed using whole-genome sequencing and comparative genomics to explore their genetic diversity, as well as genotype and phenotype analysis for carbohydrate utilization and antibiotic tolerance. The phylogenetic tree was independent of region, age and feeding mode, and without any regularity in the clustering of carbohydrates and antibiotics at the genetic level. Based on genotypic-phenotypic correlation analysis, the diversity of glycosyl hydrolases and the ability of strains to metabolize carbohydrates corroborated the predominance of B. breve in the children's intestines. Simultaneously, the sensitivity of strains to antibiotics increased the understanding of its genetic features and provided a potential basis for safety evaluation.
    • Expression, purification and antimicrobial activity of recombinant pediocin PA-1 M31L, a PA-1 derivative with enhanced stability

      Kuniyoshi, Taís Mayumi; O’ Connor, Paula M.; Arbulu, Sara; Mesa-Pereira, Beatriz; Pinheiro de Souza Oliveira, Ricardo; Hill, Collin; Ross, Paul; Cotter, Paul D. (Microbiology Society, 2019-03-01)
      Pediocin, the prototypical class IIa bacteriocin, is an efficient antilisterial molecule. Loss of pediocin PA-1 activity is attributed to methionine oxidation at position 31 and this can be overcome by substituting methionine for leucine (pediocin M31L). The aim of this study was to produce pediocin M31L with enhanced stability by recombinant expression in E. coli cells.
    • Extensive bacteriocin gene shuffling in the Streptococcus bovis/Streptococcus equinus complex reveals gallocin D with activity against vancomycin resistant enterococci

      Hill, Daragh; O’Connor, Paula M.; Altermann, Eric; Day, Li; Hill, Colin; STANTON, CATHERINE; Ross, Paul; Teagasc Walsh Fellowship Programme; Science Foundation Ireland; SFI/12/RC/2273 (Springer Science and Business Media LLC, 2020-08-10)
      Streptococcus gallolyticus LL009 produces gallocin D, a narrow spectrum two component bacteriocin with potent activity against vancomycin-resistant enterococci. Gallocin D is distinct from gallocin A, a separate two component bacteriocin produced by S. gallolyticus. Although the gene clusters encoding gallocin A and gallocin D have a high degree of gene synteny, the structural genes are highly variable and appear to have undergone gene shufing with other streptococcal species. Gallocin D was analysed in laboratory-based experiments. The mature peptides are 3,343± 1 Da and 3,019 ± 1 Da and could be readily synthesized and display activity against a vancomycin resistant Enterococcus strain EC300 with a MIC value of 1.56 µM. Importantly, these bacteriocins could contribute to the ability of S. gallolyticus to colonize the colon where they have been associated with colorectal cancer.
    • Marked elevations in pro-inflammatory polyunsaturated fatty acid metabolites in females with irritable bowel syndrome

      Clarke, Gerard; Fitzgerald, Peter; Hennessy, Alan A.; Cassidy, Eugene M.; Quigley M., Eamonn M.; Ross, Paul; STANTON, CATHERINE; Cryan, John F.; Dinan, Timothy G. (Elsevier, 2021-01-04)
      Irritable bowel syndrome (IBS) is the most common functional gastrointestinal disorder referred to gastroenterologists. Although the pathophysiology remains unclear, accumulating evidence points to the presence of low-level immune activation both in the gut and systemically. Circulating polyunsaturated fatty acids (PUFA) have recently attracted attention as being altered in a variety of disease states. Arachidonic acid (AA), in particular, has been implicated in the development of a pro-inflammatory profile in a number of immune-related disorders. AA is the precursor of a number of important immunomodulatory eicosanoids, including prostaglandin E2 (PGE2) and leukotriene B4 (LTB4). We investigated the hypothesis that elevated plasma AA concentrations in plasma contribute to the proposed pro-inflammatory profile in IBS. Plasma AA and related PUFA were quantified by gas chromatography analysis in IBS patients and controls. Both PGE2 and LTB4 were measured in serum using commercially available ELISA assays. AA concentrations were elevated in our patient cohort compared with healthy controls. Moreover, we demonstrated that this disturbance in plasma AA concentrations leads to downstream elevations in eicosanoids. Together, our data identifies a novel proinflammatory mechanism in irritable bowel syndrome and also suggests that elevated arachidonic acid levels in plasma may serve as putative biological markers in this condition.