Selvin Stanley Solis
Academic and research departments
Department of Nutrition, Food and Exercise Sciences, School of Biosciences.About
My research project
Molecular mechanisms underlying the beneficial immunomodulatory properties of commensal bacteriaThe microbial diversity in human (and animal) microbiomes and their correlations with medical conditions have revolutionized the fields of Medicine and Biosciences. However, it is uncertain which host commensal microbes are the main drivers that restore/protect health from disease, and the molecules they possess to interact with the immune system. We have addressed this important question using a luciferase reporter infection model to reveal the molecules that commensal bacteria utilize to induce host-beneficial responses. Our investigations have shown that certain species of lactobacilli, which are popular as probiotics worldwide, trigger macrophages to produce high levels of type I interferon (IFN-I) cytokines, which are essential to confer protection against microbial infections and auto-immune disorders. For the first time, we have proved that this IFN-I activation is predominantly driven by cGAS, a molecule that activates the cytosolic sensor STING upon the recognition of bacterial DNA. Furthermore, we have observed that lactobacilli encode some surface proteins with the potential to interact with macrophages for subsequent phagocytosis via non-opsonic scavenger receptors. Therefore, we are focused on determining the role that these surface proteins play as a port of entry in macrophages and characterizing the IFN-I-mediated intracellular signaling initiated by cGAS. Elucidating these unknown mechanisms will be important to inform on how specific molecules of commensals modulate or stimulate host responses that, in unhealthy individuals, are exacerbated or inhibited. Overall, our studies will provide a better understanding on the molecular crosstalk between the microbiome and mammalian cells, paving the way for major therapeutic discoveries.
Supervisors
The microbial diversity in human (and animal) microbiomes and their correlations with medical conditions have revolutionized the fields of Medicine and Biosciences. However, it is uncertain which host commensal microbes are the main drivers that restore/protect health from disease, and the molecules they possess to interact with the immune system. We have addressed this important question using a luciferase reporter infection model to reveal the molecules that commensal bacteria utilize to induce host-beneficial responses. Our investigations have shown that certain species of lactobacilli, which are popular as probiotics worldwide, trigger macrophages to produce high levels of type I interferon (IFN-I) cytokines, which are essential to confer protection against microbial infections and auto-immune disorders. For the first time, we have proved that this IFN-I activation is predominantly driven by cGAS, a molecule that activates the cytosolic sensor STING upon the recognition of bacterial DNA. Furthermore, we have observed that lactobacilli encode some surface proteins with the potential to interact with macrophages for subsequent phagocytosis via non-opsonic scavenger receptors. Therefore, we are focused on determining the role that these surface proteins play as a port of entry in macrophages and characterizing the IFN-I-mediated intracellular signaling initiated by cGAS. Elucidating these unknown mechanisms will be important to inform on how specific molecules of commensals modulate or stimulate host responses that, in unhealthy individuals, are exacerbated or inhibited. Overall, our studies will provide a better understanding on the molecular crosstalk between the microbiome and mammalian cells, paving the way for major therapeutic discoveries.
My qualifications
Teaching
Assist in the teaching and assessment process as a Demonstrator for Lab Practicals on the following modules:
BMS1035: Practical Bacteriology
BMS2049: Food Microbiology
BMS2045: Introduction to Immunology
BMS3060: Biomedical Products
BMS3071: Food Security
Publications
Two efficient feather-degrading bacteria were isolated from honeybee samples and identified as Bacillus sonorensis and Bacillus licheniformis based on 16S rRNA and genome sequencing. The strains were able to grow on chicken feathers as the sole carbon and nitrogen sources and degraded the feathers in a few days. The highest keratinase activity was detected by the B. licheniformis CG1 strain (3800 U × mL−1), followed by B. sonorensis AB7 (1450 U × mL−1). Keratinase from B. licheniformis CG1 was shown to be active across a wide range of pH, potentially making this strain advantageous for further industrial applications. All isolates displayed antimicrobial activity against Micrococcus luteus; however, only B. licheniformis CG1 was able to inhibit the growth of Mycobacterium smegmatis. In silico analysis using BAGEL and antiSMASH identified gene clusters associated with the synthesis of non-ribosomal peptide synthetases (NRPS), polyketide synthases (PKSs) and/or ribosomally synthesized and post-translationally modified peptides (RiPPs) in most of the Bacillus isolates. B. licheniformis CG1, the only strain that inhibited the growth of the mycobacterial strain, contained sequences with 100% similarity to lichenysin (also present in the other isolates) and lichenicidin (only present in the CG1 strain). Both compounds have been described to display antimicrobial activity against distinct bacteria. In summary, in this work, we have isolated a strain (B. licheniformis CG1) with promising potential for use in different industrial applications, including animal nutrition, leather processing, detergent formulation and feather degradation.