Browsing by Author "Chanyi RM"

Now showing 1 - 9 of 9
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    Complete Genome Sequences of Eight Faecalibacterium sp. Strains Isolated from Healthy Human Stool
    (American Society for Microbiology, 2023-01-24) Fraccascia D; Chanyi RM; Altermann E; Roy NC; Flint SH; McNabb WC; Dunning Hotopp JC
    Eight Faecalibacterium sp. strains were isolated from feces of healthy human volunteers. Here, we describe their genome sequences. The genome sizes ranged from 2.78 Mbp to 3.23 Mbp, with an average GC content of 56.6% and encoding 2,795 protein-coding genes on average.
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    Corrigendum: New perspectives on an old grouping: the genomic and phenotypic variability of Oxalobacter formigenes and the implications for calcium oxalate stone prevention.
    (Frontiers Media S.A., 2023-06-12) Chmiel JA; Carr C; Stuivenberg GA; Venema R; Chanyi RM; Al KF; Giguere D; Say H; Akouris PP; Domínguez Romero SA; Kwong A; Tai V; Koval SF; Razvi H; Bjazevic J; Burton JP
    [This corrects the article DOI: 10.3389/fmicb.2022.1011102.].
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    Differences in Aroma Metabolite Profile, Microstructure, and Rheological Properties of Fermented Milk Using Different Cultures
    (MDPI (Basel, Switzerland), 2023-05-02) Nguyen HTH; Gomes Reis M; Wa Y; Alfante R; Chanyi RM; Altermann E; Day L; Božani´c R
    Texture and flavour are the key attributes determining sensory quality and are highly affected by starter cultures. A selection of phenotypic strains is needed to create diverse texture and flavour to meet consumers' preferences. In this study, the use of five lactic acid bacteria strains in the production of fermented milk, along with the metabolite profiles, microstructure, and rheological properties of the fermented milk samples, was investigated. Our results showed that Lactobacillus helveticus (LH) and Streptococcus thermophilus (ST) had a stronger acidification during fermentation but resulted in products with a coarser protein network compared to Lactococcus lactis (BL1) and Leuconostoc mesenteroides (CL3). Milk fermented by LH had the highest viscosity and exopolysaccharide concentration, while milk fermented by ST had the highest concentration of diacetyl. Although Leuconostoc pseudomesenteroides (CL3ST) had a minimal acidification capability, it produced high levels of ethyl-derived compounds associated with sweet, fruity, and floral fragrances. The results demonstrated that LH and ST could be used as starter cultures targeting fermented milks with different viscosities, while BL1, CL3, and CL3ST are suitable as adjunct cultures to impact different acidic sharpness and flavour notes.
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    Extracellular Polysaccharide Extraction from Streptococcus thermophilus in Fermented Milk.
    (American Society for Microbiology, 2022-04-27) Wa Y; Chanyi RM; Nguyen HTH; Gu R; Day L; Altermann E; Cocolin L
    Lactic acid bacteria such as Streptococcus thermophilus are known to produce extracellular polysaccharide (EPS) in fermented foods that enhance the creaminess and mouthfeel of the product, such as yogurt. Strains producing larger amounts of EPS are highly sought-after, and therefore, robust and accurate quantification methodologies are important. This study found that two commonly used methodologies significantly underestimated the amount of EPS produced as measured using a milk matrix. To this end, a proteolytic step was implemented prior to EPS extraction (Method C). An initial proteolytic step using xanthan gum-spiked milk significantly increased recovery yield to 64%, compared to 27.8% for Method A and 34.3% for Method B. Method C showed no improvement when assessed using a chemically defined medium. Method C was further validated using three strains of S. thermophilus with varying EPS-production capabilities (STLOW, STMID, STHIGH). Overall, Method C demonstrated significant improvements in the EPS extraction yield for all three S. thermophilus strains in fermented milk. On average, Method C improved isolation yield by ∼3- to 6-fold compared with Method A and by ∼2- to 3-fold compared with method B. There were no significant differences between samples when they were grown in a chemically defined medium, highlighting the importance of a proteolytic step specifically for fermented milk samples. In commercial applications, accurate quantification of EPS-production is an important aspect when finding new strains. IMPORTANCE Extracellular polysaccharide (EPS) production by milk-fermenting microorganisms is a highly sought-after trait in improving the perceived thickness, creaminess, and mouthfeel of yogurt. Streptococcus thermophilus are commonly isolated and their EPS production is quantified in the search for higher-producing strains. In this study, we demonstrated that two commonly used methods for isolating EPS from milk samples significantly underestimated the true amount of EPS present. We demonstrated that the addition of a proteolytic step prior to EPS extraction isolated over 2-fold more EPS than identical samples processed using the traditional protocols. We further validated this method in fermented milk samples from three strains of S. thermophilus that included a low-, mid-, and high-EPS producing strain. Again, we showed significant improvements in EPS isolation using a proteolytic step. In the search for new S. thermophilus strains with enhanced EPS production, accurate quantification in an optimal medium is essential.
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    Inflatable Penile Prostheses Implantation: Does Antibiotic Exposure Matter?
    (Oxford University Press, 2018-09-01) Chanyi RM; Alzubaidi R; Leung EJY; Wilcox HB; Brock GB; Burton JP
    BACKGROUND: Inflatable penile prosthetic (IPP) infections are unusual but carry high patient morbidity and healthcare costs. AIM: To increase the bactericidal effect of IPP tubing material to prevent future bacterial infections and to determine whether this effect is time-dependent. METHODS: A modified disk diffusion assay was developed to measure the zones of inhibition against Escherichia coli, Proteus mirabilis, Staphylococcus aureus, and Staphylococcus epidermidis when tubing was immersed in gentamycin, ampicillin, tetracycline, kanamycin, erythromycin, or ciprofloxacin. To further assess the efficacy of this approach, IPP tubing was exposed to ampicillin or ciprofloxacin for 30 seconds, 2 minutes, 10 minutes, or 60 minutes. OUTCOMES: Bacterial zones of inhibition against IPP tubing material exposed to various treatments. RESULTS: IPP tubing was more effective against Gram-positive bacteria (S aureus and S epidermidis) then Gram-negative bacteria (E coli and P mirabilis). Immersing IPP tubing material in ampicillin or ciprofloxacin increased bactericidal effect of tubing material against Gram-positive and Gram-negative bacteria, respectively. The observed inhibitory effect was time dependent. CLINICAL TRANSLATION: Exposing IPP to a specific antimicrobial directly before implantation increases the bactericidal properties of the material, potentially decreasing the likelihood of infection. STRENGTHS & LIMITATIONS: This study is limited in that it is in vitro experimentation observing the effect of a single strain of each bacterium. Although the strains used were clinically relevant, further analysis is required to determine whether these results were strain specific. CONCLUSION: Immersing IPP material into an antibiotic solution, such as ampicillin or ciprofloxacin, increases the bactericidal properties and may aid in the prevention of infection.
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    Moving on from Metchnikoff: thinking about microbiome therapeutics in cancer.
    (ecancer Global Foundation, 2018-09-05) Maleki Vareki S; Chanyi RM; Abdur-Rashid K; Brennan L; Burton JP
    Precision medicine now needs to also consider the microbiome in oncology treatment. Ingested substances, whether they are a carcinogenic or therapeutic agent, will likely come into contact with the microbiota. Even those delivered extra-intestinally can be influenced beyond xenobiotic metabolism by biochemical factors associated with the microbiota or by an immunological predisposition created by the microbiome. We need to undertake one of the largest paradigm shifts to ever occur in medicine, that is, every drug or ingested substance needs to be re-evaluated for its pharmacological effect post-microbiome interaction. The importance of the microbiome with a focus on the treatment of cancer is discussed. In the near future, it may be possible to specifically manipulate the microbial composition within cancer patients to improve the therapeutic potential of existing oncological agents. However, the current tools to do so are limited. Targeted modulation is likely to be achieved by addition, selective enhancement or depletion of specific microbial types. This may include compounds such as narrow spectrum antimicrobial agents or oligosaccharides that will kill or enhance the bacterial growth of distinct members of the microbiota, respectively. This will stimulate a new era in these fields.
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    New perspectives on an old grouping: The genomic and phenotypic variability of Oxalobacter formigenes and the implications for calcium oxalate stone prevention.
    (Frontiers Media S.A., 2022-12-21) Chmiel JA; Carr C; Stuivenberg GA; Venema R; Chanyi RM; Al KF; Giguere D; Say H; Akouris PP; Domínguez Romero SA; Kwong A; Tai V; Koval SF; Razvi H; Bjazevic J; Burton JP; Sutcliffe I
    Oxalobacter formigenes is a unique bacterium with the ability to metabolize oxalate as a primary carbon source. Most kidney stones in humans are composed of calcium and oxalate. Therefore, supplementation with an oxalate-degrading bacterium may reduce stone burden in patients suffering from recurrent calcium oxalate-based urolithiasis. Strains of O. formigenes are divided into two groups: group I and group II. However, the differences between strains from each group remain unclear and elucidating these distinctions will provide a better understanding of their physiology and potential clinical applications. Here, genomes from multiple O. formigenes strains underwent whole genome sequencing followed by phylogenetic and functional analyses. Genetic differences suggest that the O. formigenes taxon should be divided into an additional three species: Oxalobacter aliiformigenes sp. nov, Oxalobacter paeniformigenes sp. nov, and Oxalobacter paraformigenes sp. nov. Despite the similarities in the oxalyl-CoA gene (oxc), which is essential for oxalate degradation, these strains have multiple unique genetic features that may be potential exploited for clinical use. Further investigation into the growth of these strains in a simulated fecal environment revealed that O. aliiformigenes strains are capable of thriving within the human gut microbiota. O. aliiformigenes may be a better therapeutic candidate than current group I strains (retaining the name O. formigenes), which have been previously tested and shown to be ineffective as an oral supplement to mitigate stone disease. By performing genomic analyses and identifying these novel characteristics, Oxalobacter strains better suited to mitigation of calcium oxalate-based urolithiasis may be identified in the future.
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    Streptococcus salivarius inhibits immune activation by periodontal disease pathogens
    (BioMed Central Ltd, 2021-05-07) MacDonald KW; Chanyi RM; Macklaim JM; Cadieux PA; Reid G; Burton JP
    BACKGROUND: Periodontal disease represents a major health concern. The administration of beneficial microbes has been increasing in popularity over efforts to manipulate the microbes using antimicrobial agents. This study determined the ability of Streptococcus salivarius to inhibit IL-6 and IL-8 production by gingival fibroblasts when activated by periodontal pathogens and their effect on the salivary microbiome. METHODS: Primary human gingival fibroblasts were challenged with Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum and a combination of all three. IL-6 and IL-8 cytokine release were measured. Using this same model, S. salivarius K12, M18 and different supernatant and whole-cell lysate fractions of S. salivarius K12 were administered to pathogen-induced fibroblasts. A patient study of healthy participants was also conducted to determine the effect S. salivarius K12 had on the native microbiome using 16S next generation sequence analysis. RESULTS: All pathogens tested induced a significant IL-6 and IL-8 response. S. salivarius K12 or M18, did not exhibit an increase in inflammatory cytokines. When either of the probiotic strains were co-administered with a pathogen, there were significant reductions in both IL-6 and IL-8 release. This effect was also observed when gingival fibroblasts were pre-treated with either S. salivarius K12 or M18 and then stimulated with the oral pathogens. Chewing gum containing S. salivarius K12 did not alter the salivary microbiome and did not increase inflammatory markers in the oral cavity. CONCLUSION: S. salivarius K12 and M18 prevented immune activation induced by periodontal disease pathogens. S. salivarius K12 did not alter the salivary microbiome or induce immune activation when administered as a chewing gum. These results warrant further study to determine if it may be an effective treatment in a model of periodontal disease.
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    The evolution of bacterial genome assemblies - where do we need to go next?
    (OAE Publishing Inc., 2022-04-12) Altermann E; Tegetmeyer HE; Chanyi RM; Ventura M
    Genome sequencing has fundamentally changed our ability to decipher and understand the genetic blueprint of life and how it changes over time in response to environmental and evolutionary pressures. The pace of sequencing is still increasing in response to advances in technologies, paving the way from sequenced genes to genomes to metagenomes to metagenome-assembled genomes (MAGs). Our ability to interrogate increasingly complex microbial communities through metagenomes and MAGs is opening up a tantalizing future where we may be able to delve deeper into the mechanisms and genetic responses emerging over time. In the near future, we will be able to detect MAG assembly variations within strains originating from diverging sub-populations, and one of the emerging challenges will be to capture these variations in a biologically relevant way. Here, we present a brief overview of sequencing technologies and the current state of metagenome assemblies to suggest the need to develop new data formats that can capture the genetic variations within strains and communities, which previously remained invisible due to sequencing technology limitations.