
Dr Giuseppina Mariano
About
Biography
I obtained my PhD at the University of Dundee in 2018, investigating the mechanism of antibacterial toxins secreted by the Type VI Secretion System.
After a short post-doctoral experience in Sheffield in 2020, I was awarded a Wellcome Trust Sir Henry Wellcome fellowship for 4 years to investigate the mechanism of antiphage systems. In 2023, I was appointed as a Lecturer at the University of Surrey, and my research programme mainly focuses on discovering and characterising antiphage systems in Serratia marcescens. We further investigate the mobilisation and evolution of these systems within genera, and we ultimately aim to understand the ecological, evolutionary and commercial impact of novel antiphage systems.
ResearchResearch interests
Bacteriophages (phages) outnumber bacteria in the environment. This selective pressure has driven bacteria to develop many anti-viral strategies and phages to evolve counter-measures. In recent years ~170 new antiphage systems have been discovered in bacterial genomes. Understanding this arms race is revealing exciting new areas of biology, and unexpected links between phage defence and the innate immune systems of animals and plants.
My research uses comparative genomics, genetics, biochemistry, single-cell microscopy and structural biology to discover new loci involved in phage defence and define the mechanistic details of their defence pathways, including understanding how interaction with phages triggers these systems and the downstream responses that lead to immunity. I am particularly focused on antiphage systems found in Serratia marcescens (and other spp.), but the lab also works on Escherichia coli, Pseudomonas aeruginosa and Bacillus spp.
Research interests
Bacteriophages (phages) outnumber bacteria in the environment. This selective pressure has driven bacteria to develop many anti-viral strategies and phages to evolve counter-measures. In recent years ~170 new antiphage systems have been discovered in bacterial genomes. Understanding this arms race is revealing exciting new areas of biology, and unexpected links between phage defence and the innate immune systems of animals and plants.
My research uses comparative genomics, genetics, biochemistry, single-cell microscopy and structural biology to discover new loci involved in phage defence and define the mechanistic details of their defence pathways, including understanding how interaction with phages triggers these systems and the downstream responses that lead to immunity. I am particularly focused on antiphage systems found in Serratia marcescens (and other spp.), but the lab also works on Escherichia coli, Pseudomonas aeruginosa and Bacillus spp.
Supervision
Postgraduate research supervision
Investigation of a novel DNA modification pathway that promotes bacterial immunity
(PhD studentiship-on going)
Teaching
I teach on the following modules:
BMS1049-1054: Biochemistry-Understanding the chemistry of life
BMS3079:Human Microbial Diseases.
Publications
Competitive bacteria-bacteriophage interactions have resulted in the evolution of a plethora of bacterial defense systems preventing phage propagation. In recent years, computational and bioinformatic approaches have underpinned the discovery of numerous novel bacterial defense systems. Anti-phage systems are frequently encoded together in genomic loci termed defense islands. Here we report the identification and characterisation of a novel anti-phage system, that we have termed Shield, which forms part of the Pseudomonas defensive arsenal. The Shield system comprises the core component ShdA, a membrane-bound protein harboring an RmuC domain. Heterologous production of ShdA alone is sufficient to mediate bacterial immunity against several phages. We demonstrate that Shield and ShdA confer population-level immunity and that they can also decrease transformation efficiency. We further show that ShdA homologues can degrade DNA in vitro and, when expressed in a heterologous host, can alter the organisation of the host chromosomal DNA. Use of comparative genomic approaches identified how Shield can be divided into four subtypes, three of which contain additional components that in some cases can negatively affect the activity of ShdA and/or provide additional lines of phage defense. Collectively, our results identify a new player within the Pseudomonas bacterial immunity arsenal that displays a novel mechanism of protection, and reveals a role for RmuC domains in phage defense.
Additional publications
- Kelly,A, Went, S.C., Mariano, G., Shaw, L.P., Picton, D.M., Duffnera, S.J.; et al., (2023). Diverse Durham collection phages demonstrate complex BREX defence responses. AEV, In Press
- Mariano, G.*, and Blower, T.R. (2023). Conserved domains can be found across distinct phage defence systems. Mol Microbiol. 10.1111/mmi.15047.
- Ulhuq, F. R., and Mariano, G*. (2022). Bacterial pore-forming toxins. Microbiology, 168. *Lead and corresponding author
- Garrett, S.R., Mariano, G., and Palmer, T. (2022) Genomic analysis of Staphylococcus aureus strain RN6390 progenitor strains. Access Microbiology
- Garrett, S.R., Mariano, G., Dicks, J., and Palmer, T. (2022). Homologous recombination between tandem paralogues drives evolution of a subset of type VII secretion system immunity genes in firmicute bacteria. Microbial Genomics 8, 000868. 10.1099/mgen.0.000868.
- Mariano, G., Faba-Rodriguez, R., Bui, S., Zhao, W., Ross, J., Tzokov, S. B., et al. (2022). Oligomerization of the FliF Domains Suggests a Coordinated Assembly of the Bacterial Flagellum MS Ring. Front. Microbiol. 0. doi: 10.3389/fmicb.2021.781960.
- Mariano, G*., Farthing, R. J., Lale-Farjat, S. L. M., and Bergeron, J. R. C. (2020). Structural Characterization of SARS-CoV-2: Where We Are, and Where We Need to Be. Front Mol Biosci 7, 605236. doi:10.3389/fmolb.2020.605236. * Co-corresponding author
- Mariano, G., Trunk, K., Williams, D. J., Monlezun, L., Strahl, H., Pitt, S. J., & Coulthurst, S. J. (2019). A family of Type VI secretion system effector proteins that form ion-selective pores. Nature Communications, 10(1), 1-15. (Chosen for Nature Review Microbiology Research Highlights)
- Mariano, G., Monlezun, L., & Coulthurst, S. J. (2018). Dual Role for DsbA in Attacking and Targeted Bacterial Cells during Type VI Secretion System-Mediated Competition. Cell Reports, 22(3), 774-785. (This publication was recommended by F1000 society).
- Ostrowski, A., Cianfanelli, F.R., Porter, M., Mariano, G., Peltier, J., Wong, J.J., Swedlow, J.R., Trost, M., and Coulthurst, S.J. (2018). Killing with proficiency: Integrated post-translational regulation of an offensive Type VI secretion system. PLoS Pathog. 14, e1007230.