Mahfuzur Sarker
Bacterial Pathogenesis, Clostridium perfringens
Presidential Award for
Scientists and Engineers ((Barometer article)
Research Interests: Bacterial Pathogenesis; molecular pathogenesis of Clostridium perfringens, food poisoning, non-food-borne human Gastrointestinal (GI) Diseases, GI diseases in domestic animals
Office: 422 Nash Hall
Courses taught: MB 440/540 Food Microbiology
Degrees: Ph.D. University of Tokushima, Tokushima Japan
Research
My laboratory group investigates the molecular pathogenesis of C. perfringens type A isolates associated with C. perfringens type A food poisoning and non-food-borne gastrointestinal (GI) diseases in humans. Specifically we investigate i) the molecular mechanism of C. perfringens sporulation, ii) the sporulation-regulated synthesis of C. perfringens enterotoxin (CPE), a major virulence factor of C. perfringens pathogensis, and iii) the mechanism of spore heat resistance. We also investigate the role of Beta2 toxin, a newly discovered toxin, in the pathogenesis of C. perfringens isolates associated with GI diseases in humans and domestic animals.
To achieve the proposed research goals, a variety of experimental approaches are used which span the disciplines of microbiology, molecular biology, cell biology, genetics and biochemistry.
By constructing isogenic knock-out mutants we first demonstrated that sporulation-regulated CPE expression is necessary for the pathogenesis of both C. perfringens type A food poisoning and non-food-borne GI disease isolates. Recently, our spo0A knock-out mutant studies have provided some of the first direct genetic evidence supporting spore-formation is essential for production of CPE by cpe-positive C. perfringens. We have also demonstrated, by genotypic and phenotypic characterization of a large number of animal GI disease isolates, that the Beta2-toxigenic C. perfringens isolates are highly associated with GI diseases in domestic animals. Collectively, these findings provide a key part of the foundation for our future research plan outlined above.
The gram-positive, spore forming, anaerobic C. perfringens bacteria is an important cause of both histotoxic and GI diseases in humans and domestic animals. C. perfringens type A food poisoning currently ranks as the third most commonly reported food-borne disease in the United States. In the U.S. alone C. perfringens type A food poisoning results in annual economic losses of over $120 million dollars. A vaccine is badly needed to prevent clostridial diseases, but vaccine development is complicated by the lack of an understanding of the molecular biology of the clostridia. We anticipate that our research will facilitate the designing and developing a vaccine against C. perfringens-associated GI diseases.
SELECTED PUBLICATIONS
Raju D., and M. R. Sarker. 2006. Expression of genes encoding small, acid-soluble spore proteins (SASPs), and the production of SASPs, in Clostridium perfringens isolates carrying enterotoxin gene on the plasmid. Can. J. Microbiol. (In Press).
Raju D., M. Waters, P. Setlow, and M. R. Sarker. 2006. Investigating the Role of small, acid-soluble spore proteins in the resistance of Clostridium perfringens spores to heat. BMC Microbiol. 6:50.
Philippe, V. A., M. B. Méndez, I. Huang, L. M. Orsaria, M. R. Sarker and R. R. Grau. 2006. Phosphate, an environmental signal inducing sporulation and enterotoxin production in the intestinal pathogen Clostridium perfringens. Infect. Immun. 74: 3651-3656.
Huang, I., and M. R. Sarker. 2006. Complementation of Clostridium perfringens spo0A mutant with wild-type spo0A gene from other Clostridium species. Appl. Env. Microbiol. 72: 6388-6393.
Harrison, B., D. Raju, H. S. Garmory, M. M. Brett, R. W. Titball and M. R. Sarker. 2005. Molecular Characterization of Clostridium perfringens Isolates from Humans with Infectious Intestinal Diseases: Evidence for Transcriptional Regulation of Beta2-toxin Gene. Appl. Env. Microbiol. 71: 8362-8370.
Raju, D. and M. R. Sarker. 2005. Comparison of the Levels of Heat Resistance of Wild-type, cpe Knock-out and cpe Plasmid-cured Clostridium perfringens Type A Strains. Appl. Env. Microbiol. 71: 6718-6120.
Waters, M., D. Raju, H. S. Garmory, M. R. Popoff, and M. R. Sarker. 2005. Regulated Expression of Beta2-toxin gene (cpb2) in Clostridium perfringens Isolates Associated with Horse Gastrointestinal Diseases. J. Clin. Microbiol. 43: 4002-4009.
Fisher, D. J., K. Miyamoto, B. Harrison, M. R. Sarker, and B. A. McClane. 2005. Association of Beta2 Toxin Production with Clostridium perfringens Type A Human Gastrointestinal Disease Isolates Carrying a Plasmid Enterotoxin Gene. Mol. Microbiol. 65: 747-762.
Huang, I., M. Waters, R. R. Grau, and M. R. Sarker. 2004. Disruption of the Gene (spo0A) Encoding Sporulation Transcription Factor Blocks Endospore Formation and Enterotoxin Production in Enterotoxigenic Clostridium perfringens Type A. FEMS Microbiol. Lett. 234: 234-240.
M. Waters, A. Savoie, H. S. Garmory, D. Bueschel, M. R. Popoff, J. G. Songer, R. W. Titball, B. A. McClane and M. R. Sarker. 2003. Genotyping of Beta2-Toxigenic Clostridium perfringens Fecal Isolates Associated with Gastrointestinal Diseases in Piglets. J. Clin. Microbiol. 41: 3584-3591.
T. Kuwahara, M. R. Sarker, H. Ugai, S. Akimoto, S. Shaheduzzaman, H. Nakayama, T. Miki, Y. Ohnishi. 2002. Physical and genetic map of the Bacteroides fragilis YCH46 chromosome. FEMS Microbiol. Lett. 207: 193-197.
S. Brynestad, M. R. Sarker, B. A. McClane, P.E. Granum and J. I. Rood. 2001. The Enterotoxin Plasmid from Clostridium perfringens Is Conjugative. Infection Immunity . 69: 3483-3487.
S.G. Sparks, R. J. Carman, M. R. Sarker and B. A. McClane. 2001. Genotyping of Enterotoxigenic Clostridium perfringens Fecal Isolates Associated with Antibiotic-Associated Diarrhea and Food Poisoning in North America. J. Clinical Microbiology. 39: 883-888.
M. R. Sarker, R. Shivers, S. G. Sparks, V. K. Juneja and B. A. McClane. 2000. Comparative Experiments To Examine the Effects od Heating on Vegetative Cells and Spores of Clostridium perfringens Isolates Carrying Plasmid versus Chromosomal Enterotoxin Genes. Applied and Environmental Microbiology . 66: 3234-3240.
M. R. Sarker, U. Singh and B. McClane. 2000. An Update on Clostridium perfringens Enterotoxin. J . Natural Toxins. 9: 251-266.
M. R. Sarker, R. J. Carman and B. McClane. 1999. Inactivation of the Gene (cpe) Encoding Clostridium perfringens Enterotoxin Eliminates the Ability of Two cpe-Positive C. perfringens Type A Human Gastrointestinal Disease Isolates to Affect Rabbit Ileal Loops. Molecular Microbiology . 33: 946-958.
M. R. Sarker, M-P. Sory, A. P. Boyd, M. Iriarte and G. R. Cornelis.1998. LcrG is required for efficient internalization of Yersinia Yop effector proteins into eukaryotic cells. Infection and Immunity . 66: 2976-2979.
M. R. Sarker, C. Neyt, I. Stainier and G. R. Cornelis. 1998. The Yersinia Yop virulon: LcrV is required for the extrusion of the translocators yopB and YopD. J. Bacteriol. 180: 1207-1214.
S. J. Billington, E. U. Wieckowski, M. R. Sarker, D. Bueschel, J. G. Songer and B. A. McClane. 1998. Clostridium perfrrngens type E Animal Enteritis Isolates with Highly Conserved, Silent Enterotoxin Gene Sequences. Infection and Immunity . 66: 4531-4536.
M. R. Sarker and M-P. Sory, A. P. Boyd, M. Iriarte and G. R. Cornelis. 1998. Role of LcrG and LcrV in Yop secretion and translocation. Hacker et al. (Eds.), Bacterial Protein Toxins, Zent.bl. Bacteriol. Suppl. 29, Gustav Fisher, Jena, Stuttgart, Lubeck, Ulm, Germany. P 132-133.
Guy R. Cornelis, A. Bolan, A. Boyd, M. Iriarte, M. Koster, S. Mills, C. Neyt, M. R. Sarker, I. Stainer, P. Van Der Smissen and M-P. Sory. 1998. The Yersinia Yop virulon, an integrated system to neutralize macrophages. Hacker et al. (Eds.), Bacterial Protein Toxins , Zent.bl. Bacteriol. Suppl. 29, Gustav Fisher, Jena, Stuttgart, Lubeck, Ulm, Germany. P 89-96.
M. R. Sarker and G. R. Cornelis. 1997. An improved version of suicide vector pKNG101 for gene replacement in Gram-negative bacteria. Molecular Microbiology 23: 410-411.
M. R. Sarker, S. Akimoto, T. Ono, T. Kinouchi, and Y. Ohnishi. 1995. Molecular cloning of the leuB gene from Bacteroides fragilis by functional complementation in Escherichia coli. Microbiology and Immunology . 39: 15-25.
M. R. Sarker, S. Akimoto, H. Ugai, T. Kuwahara, and Y. Ohnishi. 1995. Nucleotide sequence of the gene encoding b-isopropylmalate dehydrogenase (leuB) from Bacteroides fragilis .. Microbiology and Immunology . 39: 525-529.