About Dr. Javier Santander
Name/Affiliation: Javier A. Santander, Memorial University of Newfoundland
2012 Ph.D., Microbiology, Arizona State University, USA
2001 M.Sc., Microbiology, Pontificia Universidad Catolica de Valparaiso, Chile
1999 B.Sc., Marine Biology, Universidad Catolica del Norte, Chile
2016- Assistant Professor, Department of Ocean Sciences, Memorial University of Newfoundland, Canada
2013-16 Assistant Professor, Faculty of Sciences, University Mayor, Chile
2012-13 Assistant Research Scientist. Arizona State University, Center for Infectious Diseases and Vaccinology, Biodesign Institute, Tempe, USA.
2019-23 Atlantic Fisheries Funds. Cleaner Fish – An Innovative and Green Technology for our Atlantic Salmon Aquaculture Industry. PI: Dr. Garth Fletcher; Collaborator: Javier Santander
2018-19 Canada First-Ocean Frontier Institute Seed Grant. Climate Change Influences on Marine Bacterial Pathogens: Temperature and Iron linked to Virulence and Vaccinology. (PI: Javier Santander)
2018-23 NSERC-Discovery. Investigating fish host-bacterial interactions (PI: Javier Santander)
2018-20 Canada First-Ocean Frontier Institute. Memorial University - Marine Institute. Investigating larvae vaccination. (Co-lead: Javier Santander and Jillian Wescott)
2017-19 Memorial University of Newfoundland, Seed, Bridge and Multidisciplinary Funds. Grant. Proof of concept: Bio-contained live Aeromonas salmonicida vaccine against furunculosis. (PI: Javier Santander)
2017-23 Canada First-Ocean Frontier Institute. Memorial University - University of Prince Edward Island. Developing Sustainable Control Measures for Pathogens of Cultured Fishes. (Co-lead: Javier Santander and Mark Fast)
2017-19 Vitamin initiative-Ocean Frontier Institute. Memorial University. The effect of vitamins on Atlantic salmon (Salmo salar) and lumpfish (Cyclopterus lumpus) macrophage immune response to bacterial pathogens of fish. (Co-Lead: Javier Santander and Matt Rise)
2016-18 Research & Development Corporation (RDC) of Newfoundland and Labrador. R&D-Ignite Project. Vaccine Strategies Against Bacterial Pathogens in Lumpfish (Cyclopterus lumpus) and Atlantic salmon (Salmo salar) (PI: Javier Santander).
2014-18 CONICYT, FONDECYT-Regular competition 1140330, Molecular Genetic Analysis of Aeromonas salmonicida Pathogenesis – A Vaccine Platform for Multiple Salmonid Fish Pathogens. (PI: Javier Santander)
2015-16 COPEC-UC 2014.J0.71, Iron acquisition proteins as vaccines against Piscirikettsia salmonis. University Mayor. (PI: Javier Santander)
2013-15 Funds for Innovation and Development-Chile (FIC BIP30170275-0). Technological Packaging of Functional Natural Compounds of Native Flora from Arica y Parinacota Region. (Co-PI: Carlos Echiburu-Chau and Javier Santander)
Most Significant Contributions
1. Pathogenesis of Bacterial Fish Pathogens
Funding: NSERC-Discovery, Genome Canada RP3, Ocean Frontiers Institute, Research and Development Corporation of Newfoundland and Labrador, MUN-Seed Funds, FONDECYT-Chile, COPEC-UC-Chile.
The fundamental aspects of my research program are related to the study of molecular mechanisms utilized by bacterial pathogens to hijack the fish immune system. In the context of pathogenesis, I have been exploring the mechanisms of iron acquisition and how these mechanisms are regulated. Iron is an essential element for bacterial pathogens, and during infection, there is a battle between the host and the pathogens for this element. Bacteria tightly regulate the acquisition of iron since in high concentrations this element become toxic. I have discovered the iron acquisition mechanisms of Edwardsiella ictaluri (Santander et al., 2012) and Flavobacterium columnare (Guang et al., 2013), both freshwater bacterial pathogens of fish. Currently, I am exploring the iron acquisition mechanisms of marine bacterial pathogens of fish, including Piscirickettsia salmonis (Almarza et al., 2016), Aeromonas salmonicida (Chakraborty et al., 2018), Moretiella viscosa, Vibrio anguillarum (Vasquez et al., 2018), and other aquatic pathogens.
Genomics and bioinformatics are transversal tools that serve for pathogenesis and evolution studies. In this context, we have sequenced and assembled the genome of several strains of Aeromonas salmonicida (Valderrama et al., 2017) and other bacterial pathogens (Ayala et al., 2017; Retamales et al., 2017; Vasquez et al., 2018), and currently we are exploring aspects of virulence evolution (Hossain et al., 2019). These genomes are serving as a reference for current transcriptomics studies.
Since non-condign RNAs (ncRNAs) play a role in bacterial pathogenesis, using bioinformatics tools we have predicted the ncRNA repertoire of P. salmonis (Segovia et al., 2018), A. salmonicida (Segovia et al. in preparation) and other bacterial pathogens of fish.
Also, we have described the virulence regulatory mechanisms linked to sugar utilization in A. salmonicida (Valderrama et al, 2017a) and E. ictaluri (Santander et al, 2011). Bacterial pathogens decorate its liposaccharide (LPS) with sugars to evade the innate immune system. We have shown that modified LPS, including removal of these decorative sugars, could serve a potent immune stimulant in fish, and that these decorative sugars are important for host immune evasion (Santander et al, 2013; Santander et al, 2014; Martin et al., 2015).
2. Vaccine Design against Fish Pathogens.
Funding: Government of Newfoundland and Labrador, Genome Canada RP3, Ocean Frontiers Institute, Research and Development Corporation of Newfoundland and Labrador, MUN-Seed Funds, FONDECYT-Chile, COPEC-UC-Chile. Even though aquaculture is the fastest growing food-production industry globally, this sector is plagued by diseases. Understanding how to trigger a protective immune response against bacterial infectious diseases in fish and design effective vaccines is the applied focus of my research program. Currently, I am focusing my vaccine research in two aspects, (i) injectable vaccine design and (ii) mucosal vaccine design. In the context of mucosal vaccines, I have contributed to the design of live attenuated vaccines for fish and humans. Attenuation of the pathogenic bacteria usually is achieved by deletion of genes related to virulence. Mutants of the crp gene have been successfully used as live attenuated vaccines for different hosts. I determined that the E. ictaluri Δcrp is attenuated, colonized lymphoid tissues, and conferred immune protection against the E. ictaluri challenge. Evaluation of the IgM titers indicated that bath immunization with the E. ictaluri Δcrp mutant triggered systemic and skin immune responses in catfish (Santander et al, 2011). Similar results were found in A. salmonicida Δcrp and rainbow trout challenges (Valderrama et al., 2017). Live attenuated vaccines could be utilized as antigen delivery vectors. In this context, I have developed a balanced-lethal system for antigen delivery. A balanced-lethal system consists of bacterial plasmid dependence in the absence of genes encoding for antibiotic resistance. Plasmid vector that encodes for heterologous antigens or DNA plasmid vaccines delivered by a bacterial vaccine vector required the absence of antibiotic markers. As a first step to develop an antibiotic-sensitive recombinant attenuated Edwardsiella vaccine strain, we have developed a balanced-lethal system mediated the deletion and complementation of asdA gene (Santander et al, 2010). The combination of these deletions is considered for the development of an attenuated recombinant bacterial vaccine for the catfish aquaculture industry (Patent Application US20100303863 A1).Recently, we have tested commercial vaccines and developed novel vaccines for lumpfish (Cyclopterups lumpus) and sablefish (Anoplaploma fimbria) against V. anguillarum (Chakraborty et al., 2019; Trung et al., 2018) and A. salmonicida (Chakraborty et al., 2018).Currently, I am the principal investigator of fish vaccinology, genomics, and transcriptomics project Genome Canada RP3. Whole Genome Sequencing and Transcriptome Profiling in Response to the Vaccination of Cleaner Fish Cyclopterus lumpus and Tautogolabrus adspersus. This project started on April 1st, 2019. Additionally, I am the co-lead of the Sustainable Aquaculture module within the Ocean Frontier Institute (OFI), funded by Canada First Research Excellence Fund (CFREF).