Girija Ramakrishnan


  • MSc, CCMB, Jawaharlal Nehru University, New Delhi, Indi
  • PhD, State University of New York at Stony Brook

Primary Appointment

  • Assistant Professor, Medicine- Infectious Diseases and International Health


Research Interest(s)

Iron-uptake mechanisms and Virulence Factors of Francisella tularensis; Microbial Pathogenesis

Research Description

Tularemia is a plague-like disease caused by the bacterium Francisella tularensis.  This organism is highly infectious as an aerosol and an effective vaccine for the agent does not currently exist.  My major research interest is in mechanisms governing pathogenicity of this intracellular pathogen.  Acquisition of iron in the host environment is a challenge for the pathogen, and we are studying the mechanisms for acquisition of iron using a combination of bioinformatics, genetic and proteomic methods.  Defining iron uptake and utilization mechanisms could lead to development of  vaccine and therapeutic strategies.  We are characterizing a siderophore-mediated uptake mechanism, and are also looking at transcriptional regulation of bacterial genes in response to iron.

A second research interest is the histone deacetylases of the protozoan parasite, Entamoeba histolytica.  I am interested in studying these enzymes with the goal of therapeutic intervention using specific inhibitors.

Girija Ramakrishnan is an affiliated faculty member of the Microbiology, Immunology and Infectious Diseases program.

Selected Publications

  • Nazarko T, Ozeki K, Till A, Ramakrishnan G, Lotfi P, Yan M, Subramani S. Peroxisomal Atg37 binds Atg30 or palmitoyl-CoA to regulate phagophore formation during pexophagy. The Journal of cell biology. 2014;204(4): 541-57. PMID: 24535825
  • PĂ©rez N, Ramakrishnan G. The Reduced Genome of the Francisella tularensis Live Vaccine Strain (LVS) Encodes Two Iron Acquisition Systems Essential for Optimal Growth and Virulence. PloS one. 2014;9(4): e93558. PMID: 24695402
  • Ramakrishnan G, Davaakhuu G, Kaplun L, Chung W, Rana A, Atfi A, Miele L, Tzivion G. Sirt2 Deacetylase Is A Novel AKT Binding Partner Critical For AKT Activation By Insulin. The Journal of biological chemistry. 2014. PMID: 24446434
  • Anandakumar P, Kamaraj S, Jagan S, Ramakrishnan G, Devaki T. Capsaicin provokes apoptosis and restricts benzo(a)pyrene induced lung tumorigenesis in Swiss albino mice. International immunopharmacology. 2013;17(2): 254-9. PMID: 23747734
  • Denny L, Adewole I, Anorlu R, Dreyer G, Moodley M, Smith T, Snyman L, Wiredu E, Molijn A, Quint W, Ramakrishnan G, Schmidt J. Human papillomavirus prevalence and type distribution in invasive cervical cancer in sub-Saharan Africa. International journal of cancer. Journal international du cancer. 2013;134(6): 1389-98. PMID: 23929250
  • Ging J, Tejerina-Anton R, Ramakrishnan G, Nielsen M, Murphy K, Gorham J, Nguyen T, Orlov A. Development of a conceptual framework for evaluation of nanomaterials release from nanocomposites: Environmental and toxicological implications. The Science of the total environment. 2013;473 9-19. PMID: 24361443
  • Kalaivani P, Saranya R, Ramakrishnan G, Ranju V, Sathiya S, Gayathri V, Thiyagarajan L, Venkhatesh J, Babu C, Thanikachalam S. Cuminum cyminum, a dietary spice, attenuates hypertension via endothelial nitric oxide synthase and NO pathway in renovascular hypertensive rats. Clinical and experimental hypertension (New York, N.Y. : 1993). 2013;35(7): 534-42. PMID: 23402543
  • Park J, Kim Y, Lee A, Lee Y, Kim K, Cho C, Choi H, Jenkins D, Pirog E, Molijn A, Ramakrishnan G, Chen J. Prevalence and type distribution of human papillomavirus in cervical adenocarcinoma in Korean women. Gynecologic oncology. 2013;130(1): 115-20. PMID: 23485771
  • Pendleton A, Galic M, Clarke C, Ng S, Ledesma E, Ramakrishnan G, Liu Y. Impact of rotavirus vaccination in Australian children below 5 years of age: a database study. Human vaccines & immunotherapeutics. 2013;9(8): 1617-25. PMID: 23733041
  • Phua K, Tee N, Tan N, Ramakrishnan G, Teoh Y, Bock H, Liu Y. A Hospital-Based Surveillance of Rotavirus Gastroenteritis in Children <5 Years of Age in Singapore. The Pediatric infectious disease journal. 2013. PMID: 23958814
  • Ramakrishnan G, Ramanandan G, Adam A, Xu M, Kumar N, Hendrikx R, Planken P. Enhanced terahertz emission by coherent optical absorption in ultrathin semiconductor films on metals. Optics express. 2013;21(14): 16784-98. PMID: 23938530
  • Ramakrishnan G, Sen B. The FupA/B protein uniquely facilitates transport of ferrous iron and siderophore-mediated ferric iron across the outer membrane of Francisella tularensis Live Vaccine Strain. Microbiology (Reading, England). 2013. PMID: 24307666
  • Tajiri H, Takeuchi Y, Takano T, Ohura T, Inui A, Yamamoto K, Higashidate Y, Kawashima H, Toyoda S, Ushijima K, Ramakrishnan G, Rosenlund M, Holl K. The burden of rotavirus gastroenteritis and hospital-acquired rotavirus gastroenteritis among children aged less than 6 years in Japan: a retrospective, multicenter epidemiological survey. BMC pediatrics. 2013;13 83. PMID: 23697664
  • Winship I, Armitage G, Ramakrishnan G, Dong B, Todd K, Shuaib A. Augmenting collateral blood flow during ischemic stroke via transient aortic occlusion. Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism. 2013;34(1): 61-71. PMID: 24045399
  • Anandakumar P, Kamaraj S, Jagan S, Ramakrishnan G, Asokkumar S, Naveenkumar C, Raghunandhakumar S, Devaki T. Capsaicin inhibits benzo(a)pyrene-induced lung carcinogenesis in an in vivo mouse model. Inflammation research : official journal of the European Histamine Research Society ... [et al.]. 2012;61(11): 1169-75. PMID: 22735861
  • Kajikawa K, Nagai Y, Uchiho Y, Ramakrishnan G, Kumar N, Ramanandan G, Planken P. Terahertz emission from surface-immobilized gold nanospheres. Optics letters. 2012;37(19): 4053-5. PMID: 23027276
  • Ramakrishnan G, Arjuman A, Suneja S, Das C, Chandra N. The association between insulin and low-density lipoprotein receptors. Diabetes & vascular disease research : official journal of the International Society of Diabetes and Vascular Disease. 2012;9(3): 196-204. PMID: 22278734
  • Ramakrishnan G, Kumar N, Planken P, Tanaka D, Kajikawa K. Surface plasmon-enhanced terahertz emission from a hemicyanine self-assembled monolayer. Optics express. 2012;20(4): 4067-73. PMID: 22418165
  • Ramakrishnan G, Sen B, Johnson R. Paralogous outer membrane proteins mediate uptake of different forms of iron and synergistically govern virulence in Francisella tularensis tularensis. The Journal of biological chemistry. 2012;287(30): 25191-202. PMID: 22661710 | PMCID: PMC3408188
  • Saravana Babu C, Sathiya S, Anbarasi C, Prathyusha N, Ramakrishnan G, Kalaivani P, Jyothi Priya R, Selvarajan Kesavanarayanan K, Verammal Mahadevan M, Thanikachalam S. Polyphenols in madhumega chooranam, a Siddha medicine, ameliorates carbohydrate metabolism and oxidative stress in type II diabetic rats. Journal of ethnopharmacology. 2012;142(2): 331-6. PMID: 22633981
  • Dobson M, Ramakrishnan G, Ma S, Kaplun L, Balan V, Fridman R, Tzivion G. Bimodal regulation of FoxO3 by AKT and 14-3-3. Biochimica et biophysica acta. 2011;1813(8): 1453-64. PMID: 21621563 | PMCID: PMC3237389
  • Lim F, Phua K, Lee B, Quak S, Teoh Y, Ramakrishnan G, Han H, Van Der Meeren O, Jacquets J, Bock H. Safety and reactogenicity of DTPa-HBV-IPV/Hib and DTPa-IPV/I-Hib vaccines in a post-marketing surveillance setting. The Southeast Asian journal of tropical medicine and public health. 2011;42(1): 138-47. PMID: 21323176
  • Ramakrishnan G, Planken P. Percolation-enhanced generation of terahertz pulses by optical rectification on ultrathin gold films. Optics letters. 2011;36(13): 2572-4. PMID: 21725483
  • Srivats S, Ramakrishnan G, Paddikkala J, Kurian G. An in vivo and in vitro analysis of free radical scavenging potential possessed by Desmodium gangeticum chloroform root extract: interpretation by gsms. Pakistan journal of pharmaceutical sciences. 2011;25(1): 27-34. PMID: 22186306
  • Tzivion G, Dobson M, Ramakrishnan G. FoxO transcription factors; Regulation by AKT and 14-3-3 proteins. Biochimica et biophysica acta. 2011;1813(11): 1938-45. PMID: 21708191
  • Sen B, Meeker A, Ramakrishnan G. The fslE homolog, FTL_0439 (fupA/B), mediates siderophore-dependent iron uptake in Francisella tularensis LVS. Infection and immunity. 2010;78(10): 4276-85. PMID: 20696823
  • Ramakrishnan G, Meeker A, Dragulev B. fslE is necessary for siderophore-mediated iron acquisition in Francisella tularensis Schu S4. Journal of bacteriology. 2008;190(15): 5353-61. PMID: 18539739
  • Sullivan J, Jeffery E, Shannon J, Ramakrishnan G. Characterization of the siderophore of Francisella tularensis and role of fslA in siderophore production. Journal of bacteriology. 2006;188(11): 3785-95. PMID: 16707671
  • Ramakrishnan G, Gilchrist C, Musa H, Torok M, Grant P, Mann B, Petri W. Histone acetyltransferases and deacetylase in Entamoeba histolytica. Molecular and biochemical parasitology. 2004;138(2): 205-16. PMID: 15555732
  • Ramakrishnan G, Rogers J, Mann B, Petri W. New tools for genetic analysis of Entamoeba histolytica: blasticidin S deaminase and green fluorescence protein. Parasitology international. 2001;50(1): 47-50. PMID: 11267932