Mark Lawrence

 Mark Lawrence

Department

  • Comparative Biomedical Sciences

Title

  • Director and Professor

Contacts

lawrence@cvm.msstate.edu
Office: (662) 325-1057
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Overview

Summary:

Dr. Mark Lawrence is a professor at the Mississippi State University College of Veterinary Medicine in the Department of Comparative Biomedical Sciences. He is a veterinary microbiologist specializing in aquatic animal health, especially in bacterial diseases of catfish and other aquaculture species. His professional career has been dedicated to advancing aquatic animal health and food safety, especially in farmed U.S. catfish, through research and diagnostics. In recent years, the scope of his research and collaborations have expanded to advance aquatic animal health for aquaculture in developing nations, with the goal of improving livelihoods and reducing malnutrition globally.

Dr. Lawrence currently serves as director of the U.S. Agency for International Development-funded Feed the Future Innovation Lab for Fish (Fish Innovation Lab; www.fishinnovationlab.msstate.edu). The mission of the Fish Innovation Lab is to alleviate poverty and improve nutrition in vulnerable populations through reliable and inclusive provision of fish, a nutrient-rich animal source food. The countries being served in this program include Nigeria, Bangladesh, Kenya, Cambodia, and Zambia.

Prior to serving as director of the Fish Innovation Lab, Dr. Lawrence served the Mississippi State University College of Veterinary Medicine as Associate Dean for Research and Graduate Studies from 2011-2018 (Interim Associate Dean for Research and Graduate Studies from 2010-2011). Dr. Lawrence serves as director of the Global Center for Aquatic Food Security (GCAFS) at Mississippi State University from 2014-current. The goal of GCAFS is to bring together multidisciplinary MSU experts in aquaculture, fisheries, social sciences, and agricultural economics to solve world hunger.

Dr. Lawrence began collaborations with the FAO Aquaculture Branch in 2010, and the collaboration was formalized in 2014 with the signing of a FAO-MSU Joint Declaration recognizing the MSU GCAFS as a Center of Knowledge and member of the Global Aquaculture Advancement Partnership. Dr. Lawrence’s collaborations with the FAO Aquaculture Branch culminated in two letters of agreement in which he provided expertise for FAO's development of a Progressive Management Pathway for Aquaculture Biosecurity (PMP/AB), which provides a framework for development of local, regional, and national biosecurity programs for aquaculture internationally.

Under the GCAFS, Dr. Lawrence manages the Marine Mammal-Sea Turtle Conservation, Recovery, and Management (MMST-CRM) program, which is a collaboration between Mississippi State University and the Institute for Marine Mammal Studies (IMMS) in Gulfport, MS that started in 2017. The MMST-CRM is primarily focused on marine mammal and sea turtle health and diagnostic investigations.

Dr. Lawrence has dedicated part of his professional career to serving the Mississippi catfish industry by serving as a diagnostician in the Fish Diagnostic Laboratory (FDL) at the Mississippi State University College of Veterinary Medicine. He has continuously served in the FDL from 1998-current, and over this period he served as the primary diagnostician approximately 12 weeks per year. He has personally handled over 700 diagnostic cases submitted.

Education:

  • Doctor of Philosophy (Ph.D.), Veterinary Medicine and Science, Louisiana State University and A&M College, 1997
  • Doctor of Veterinary Medicine (D.V.M.), Veterinary Medicine, Texas A&M University, 1990
  • Bachelor of Science (B.S.), Veterinary Medicine and Science, Texas A&M University, 1988

Research interests:

In research, Dr. Lawrence’s interest is in mechanisms of bacterial pathogenesis, especially the application of comparative genomics, proteomics, and gene expression analysis to identify bacterial virulence factors and develop live attenuated vaccines. His initial focus was on Edwardsiella ictaluri, which is one of the most important pathogens affecting catfish aquaculture in the U.S. Using a high throughput screening method to identify E. ictaluri mutants susceptible to catfish serum and neutrophils, an effective live attenuated vaccine was developed and patented. The role of lipopolysaccharide in E. ictaluri virulence was also investigated, and LPS mutants were tested as live attenuated vaccines.

Dr. Lawrence has also been active in research on Flavobacterium columnare, which is one of the primary pathogens affecting catfish aquaculture, but it is also an important fish pathogen globally. Dr. Lawrence’s team completed the first genome sequence of the species, developed a working challenge model in catfish, conducted one of the first comparisons of strain virulence in catfish, developed a F. columnare-specific qPCR assay, and conducted comparative genomics within the species to identify genes associated with highly virulent genetic group 2. His team is also one of the first to successfully construct gene knockouts in the species to determine the role of F. columnare denitrification enzymes in anaerobic growth and virulence.

Dr. Lawrence has also been a leader on research of Aeromonas hydrophila, which is historically considered an opportunistic fish pathogen in catfish. However, since 2009, large-scale outbreaks of disease and mortalities caused by A. hydrophila impacted channel catfish aquaculture. Using comparative genomics, a collaborative team from MSU, Auburn University, USDA ARS, and University of Arkansas-Pine Bluff determined that these outbreaks are caused by a recently emerged, highly clonal subtype of A. hydrophila. Dr. Lawrence’s team completed genome sequences for several of these strains and bioinformatically identified surface and secreted proteins produced exclusively by this clonal virulent subgroup. Genes encoding these proteins were cloned, and recombinant proteins were expressed. Several of these show potential as effective vaccine antigens. Dr. Lawrence’s team is currently pursuing construction of a recombinant vaccine by expressing these proteins in live attenuated E. ictaluri.

Listeria monocytogenes has one of the highest case fatality rates of the foodborne pathogens, and it causes several food recalls in the U.S. each year. However, despite many strains being highly virulent and causing foodborne outbreaks, other L. monocytogenes strains are non-pathogenic. Dr. Lawrence’s research interest in L. monocytogenes is to identify and characterize genes unique to pathogenic strains to better understand pathogenesis of listeriosis and to improve detection of pathogenic strains. By sequencing non-pathogenic strain HCC23 (genomovar III) and conducting comparative genomics and proteomics between pathogenic strains EGD-e and F2365 (genomovars I and II), Dr. Lawrence’s team identified protein-coding genes uniquely expressed by pathogenic strains in the context of infecting macrophages. Dr. Lawrence’s team constructed gene deletion mutants, which led to development of an improved method for deletion mutagenesis of L. monocytogenes that has been used by listerial researchers globally. Dr. Lawrence’s group determined that a cell wall surface protein designated LapB contributes to listerial virulence, and they determined the role of a new family of phosphodiesterase in regulating cyclic dinucleotides, which is a newly discovered mechanism L. monocytogenes uses to regulate expression of virulence genes.

Publications

Book, Chapter

Journal Article

Note, Journal

Published Abstract

  • Haplotype shift and genomic variation in atypical Aeromonas hydrophila (aAh) isolates of channel catfish aquaculture in the southeastern US. . The Conference of Research Workers in Animal Disease. 2020
  • Genomic analysis of atypical Aeromonas hydrophila (aAh) from catfish aquaculture in the southeastern United States with evidence of haplotype shifts from diagnostic case submissions. . AFS-FHS Virtual Summer Seminar Series. 2020

Presentations

Abstract

  • "Expanding our knowledge of the Edwardsiella. ." American Society Microbiology, , Boston, MA. 2016
  • "Comparison of Edwardsiella ictaluri isolates from different hosts and geographic origins." Food Security for the Future: The Role of Aquatic Animal Health, , Starkville, MS. 2015
  • "Recent advancements in our knowledge of Edwardsiella piscicida and E. tarda." 40th Annual Eastern Fish Health Workshop, American Fisheries Society, Charleston, South Carolina. 2015
  • "Recent advancements in our knowledge of the Edwardsiella." Food Security for the Future: The Role of Aquatic Animal Health, , Starkville, MS. 2015

Oral Presentation

  • "Haplotype and genomic variation in atypical Aeromonas hydrophila (aAh) of channel catfish aquaculture in the US ." 101st Conference of Research Workers in Animal Diseases Dec 5-8, 2020, CRWAD, CHICAGO. 2020
  • "They are the same but different: Comparative genomics of two atypical Aeromonas hydrophila pathotypes found in catfish aquaculture of the southeast." Annual Meeting of the Mississippi Chapter of the American Fisheries Society, Mississippi Chapter of the American Fisheries Society, Gulfport, MS. 2020
  • "They are the same but different: Comparative genomics of two atypical Aeromonas hydrophila pathotypes found in catfish aquaculture of the southeast." Annual Meeting of the Southern Division of the American Fisheries Society, Southern Division of the American Fisheries Society, Little Rock, AR. 2020
  • "Evaluating atypical Aeromonas hydrophila (aAh) in catfish aquaculture in the Delta region of Mississippi." Conference of Research Workers in Animal Diseases, CRWAD, Chicago, Illinois. 2018
  • "Comparative genomics reveals the species-based diversity of Edwardsiella genus members." 8th International Symposium on Aquatic Animal Health, American Fisheries Society Fish Health Section, Charlottetown, Prince Edward Island, Canada. 2018
  • "Control strategies for virulent Aeromonas hydrophila in catfish aquaculture by vaccination and informing pond management. ." Agriculture and Food Research Initiative Animal Health and Well-being Program Areas Annual Project Director Meeting , USDA, Chicago, IL. 2017
  • "Advancing our knowledge of the bacteria formerly known as Edwardsiella tarda.." 42nd Eastern Fish Health Workshop, , East Lansing, MI. 2017
  • "Expanding our knowledge of Edwarsdiella. ." American Fisheries Society Fish Health Section Annual Meeting, American Fisheries Society Fish Health Section Annual Meeting, East Lansing, MI. 2017
  • "Phenotypic and genetic characterization of Edwarsdiella isolates from different hosts and geographic regions. ." 41 st Eastern Fish Health Workshop, , Atlantic Beach, NC. 2016

Poster

  • "Control strategies for virulent Aeromonas hydrophila in catfish aquaculture by vaccination and informing pond management." CRWAD, Conference of Research Workers in Animal Diseases, Chicago, Il. 2019
  • "Control of virulent Aeromonas hydrophila in catfish aquaculture by vaccination and informing pond management." Conference of Research Workers in Animal Diseases, CRWAD, Chicago, Illinois. 2018
  • "Comparative Genomic Analysis of Virulence Factors in the Aeromonas genus." MSU Undergraduate Research Symposium, Shackouls Honors College, Mississippi State University. 2018

Areas of Expertise

Veterinary microbiology Aquatic animal health Bacterial pathogenesis Veterinary vaccines Bacterial genomics International food security Marine mammal and sea turtle health