V.K. Viswanathan

Associate Professor
V.K. Viswanathan
626-7687
ACBS, Rm. 227

1117 E. Lowell St.

The Viswanathan laboratory is interested in the interactions between pathogenic bacteria and host cells. Specifically, the study of mechanisms by which enterohemorrhagic Escherichia coli and related bacteria cause disease. Recent studies have focused on the mechanisms by which these pathogens manipulate the survival of host cells. On a broader level, Viswanathan is interested in understanding how these pathogens are disseminated in the environment, and to eventually seek methods to control their spread.

Ph.D., University of Illinois at Chicago
Associate Professor
 
School of Animal and Comparative Biomedical Sciences
University of Arizona
1117 E. Lowell Street Rm 207
Tucson, AZ 85721-0090
Telephone: (520)-626-7687
Email vkv@email.arizona.edu
 
Research interests: Interactions between entric pathogens and host intestinal epithelial cells.  Bacterial pathogenesis and Innate immunity.
 
Research:  My laboratory is interested in the interactions between pathogenic bacteria and host cells. Specifically, we study the mechanisms by which enterohemorrhagic Escherichia coli (“spinach- or hamburger E. coli”) and related bacteria cause disease. After attaching to epithelial cells in the intestine, these bacteria inject specific molecules into these cells via a specialized structure called the type III secretion system. The injected molecules specifically alter the biology of the host cells, presumably to support bacterial survival. We are interested in understanding the molecular alterations in the host cells resulting from these injected molecules, and how this eventually contributes to disease. Our studies also demonstrate that pathogenic E. coli suppress the death of host cells. Being extracellular pathogens, killing the host cell would likely result in a loss of the substratum thereby interfering with the ability to colonize. Our recent studies have focused on the mechanisms by which these pathogens manipulate the survival of host cells. On a broader level, we are interested in understanding how these pathogens are disseminated in the environment, and to eventually seek methods to control their spread.
 
Courses Taught:      
MIC/VSC 595A                Critical Evaluation of Scientific Literature (Spring)
MIC/VSC 421B (421L)     Microbial Techniques (Fall 2010)
MIC/VSC 420/520           Pathogenic Bacteriology (Fall 2011)
IMB565                           Principles & Mol. Mechnsms of Microbe-Host Interactions (Guest         lectures)
 
Selected Publications
 
Viswanathan, V.K. The Inside Passage.  Regular column in Gut Microbes, Landes Bioscience Journals. 
  1. Fascinating Science, Compelling Cause              January/February 2010
  2. Humor Me                                                            March/April 2010.
  3. Eating in, Eating out                                              July/August 2010.
  4. Tossed Salads                                                      September/October 2010
  5. Self portraits                                                        November/December 2010
  6. Mind-bending infections                                       January/February 2011
  7.  Of Cabbages & Kings                                          March/April 2011       
  8. Leptin signaling protects the gut from Entamoeba histolytica infection                                        January/February 2012
  9. Spirochaetes and their twisted ways                 September/October 2012
  10. Sizing up Microbes                                          November/December 2012
  11. Sensing bacteria, without bitterness?             March/April 2013
  12. Oh what tangled webs we weave...               May/June 2013
 
Roxas JL, Wilbur JS, Zhang X, Marinez G, Viswanathan VK. 2012.  The enteropathogenic Escherichia coli secreted protein EspZ inhibits host cell apoptosis.  Infection & Immunity.  2012 Nov; 80(11):3850-7.
 
Royan SV, Jones RM, Koutsouris A, Roxas JL, Falzari K, Weflen AW, Kim A, Bellmeyer A, Turner JR, Neish AS, Rhee K-J, Viswanathan VK, Hecht GA. 2010.  Enteropathogenic E. coli Non-LEE Encoded Effectors NleH1 and NleH2 Attenuate NF-κB Activation.  Molecular Microbiology, 78(5):1232-45.
 
Merrigan M, Venugopal A, Mallozzi M, Roxas B, Viswanathan VK, Johnson S, Gerding DN, Vedantam G.  2010. Human hypervirulent Clostridium difficile strains exhibit increased sporulation as well as robust toxin production.  J Bacteriol. 192(19):4904-11.
 
Weflen AW, Alto NM, Viswanathan VK, Hecht G. 2010. E. coli secreted protein F promotes EPEC invasion of intestinal epithelial cells via an SNX9-dependent mechanism. Cell Microbiol. 12(7):919-29.
 
Mallozzi M, Viswanathan VK, Vedantam G.  2010. Spore-forming Bacilli and Clostridia in human disease.  Future Microbiol. 2010 Jul;5(7):1109-23.

Viswanathan VK,Mallozzi M, Vedantam G. 2010. Clostridium difficile infection: An overview of the disease and its pathogenesis, epidemiology and interventions.  Gut Microbes 1:4, 1-9.

Viswanathan VK.  Diarrhea-Associated Mortality Is a Solvable Problem. 2010. AGA Perspectives.  December 2009/January 2010.

Viswanathan VK, Hodges K, Hecht G. Enteric infection meets intestinal function: how bacterial pathogens cause diarrhoea. Nat Rev Microbiol. 2009 Feb;7(2):110-9.
 
Bellmeyer A, Cotton C, Kanteti R, Koutsouris A, Viswanathan VK , Hecht G.
Enterohemorrhagic Escherichia coli suppresses inflammatory response to cytokines and its own toxin. Am J Physiol Gastrointest Liver Physiol. 2009 Sep;297(3):G576-81. Epub 2009 Jun 25.
 
Viswanathan VK, Weflen A, Koutsouris A, Roxas JL, Hecht G. Enteropathogenic E. coli-induced barrier function alteration is not a consequence of host cell apoptosis. Am J Physiol Gastrointest Liver Physiol. 2008 May;294(5):G1165-70.
 
 
Sharma R, Tesfay S, Tomson FL, Kanteti RP, Viswanathan VK, Hecht G. Balance of bacterial pro- and anti-inflammatory mediators dictates net effect of enteropathogenic Escherichia coli on intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol. 2006 Apr;290(4):G685-94.
 
Tomson FL, Viswanathan VK, Kanack KJ, Kanteti RP, Straub KV, Menet M, Kaper JB, Hecht G. Enteropathogenic Escherichia coli EspG disrupts microtubules and in conjunction with Orf3 enhances perturbation of the tight junction barrier. Mol Microbiol. 2005 Apr;56(2):447-64.
 
Viswanathan VK, Lukic S, Koutsouris A, Miao R, Muza MM, Hecht G. Cytokeratin 18 interacts with the enteropathogenic Escherichia coli secreted protein F (EspF) and is redistributed after infection. Cell Microbiol. 2004 Oct;6(10):987-97.
 
Tomson FL, Koutsouris A, Viswanathan VK, Turner JR, Savkovic SD, Hecht G. Differing roles of protein kinase C-zeta in disruption of tight junction barrier by enteropathogenic and enterohemorrhagic Escherichia coli. Gastroenterology. 2004 Sep;127(3):859-69.
 
Viswanathan VK, Koutsouris A, Lukic S, Pilkinton M, Simonovic I, Simonovic M, Hecht G. Comparative analysis of EspF from enteropathogenic and enterohemorrhagic Escherichia coli in alteration of epithelial barrier function. Infect Immun. 2004 Jun;72(6):3218-27. PubMed PMID: 15155623.
Courses Taught: 
IMB565
ACBS420/520
ACBS421B/421L
ACBS428R
ACBS595A
MIC430
MIC438