You are here

Our Research Fellows

Laure Botella, Ph.D.

Laure Botella


I studied microbiology and genetics at the University Paul Sabatier in Toulouse (France) and got my PhD from the National Institute of Applied Sciences of Toulouse (INSA) in microbial and enzymatic engineering. My work focused on the characterization and use of methylmalonyl-CoA mutase activity in Corynebacterium glutamicum and was  performed in the laboratory of Dr. Lothar Eggeling in the Institute for Biotechnology in Juelich Research Center (Germany), under the supervision of Dr Lothar Eggeling and Dr Nic Lindley (INSA Toulouse).

I joined Dr. Schnappinger Lab in 2009 and I am now working on the identification and characterization of genes required for growth and persistence of Mycobacterium tuberculosis during infections.

Nadine Ruecker, Ph.D.

Nadine Ruecker


Nadine Rücker did her PhD at the Institute of Medical Microbiology and Hospital Epidemiology at the Hannover Medical School, Germany. The main focus of her thesis was the analysis of acetate metabolism of Mycobacterium tuberculosis (Mtb). Her main interests are mycobacterial metabolism and drug development. In December 2013, she joined the lab to characterize essential genes with unknown function of Mtb.


Characterization of rough and smooth morphotypes of Mycobacterium abscessus isolated from clinical specimens; Kai RügerAnnegret HampelSandra BilligNadine RückerSebastian  Suerbaum and Franz-Christoph BangeJ Clin Microbiol. 2014 Jan;52(1):244-50. doi: 10.1128/JCM.01249-13. Epub 2013 Nov 6. 

Ritu Sharma, Ph.D.

Ritu Sharma, Ph.D.


I grew up in New Delhi, the capital city of India. I studied Biomedical Sciences at the University of Delhi where I worked on identifying and characterizing the DNA binding domain of a chromatin remodeling protein (SWI2/SNF2 like protein hINO80). I then obtained my PhD in Molecular Microbiology at the wonderful Indian Institute of Science (IISc) in Bangalore, India. My graduate research focused on understanding the role of cAMP in mycobacteria by characterizing adenylyl cyclases and cAMP receptor proteins. My work at IISc was supported by Council for Scientific and Industrial Research of the Government of India. 

I arrived at WCMC in the Spring of 2011 and have since been a member of the Dirk Schnappinger lab within the Department of Microbiology and Immunology. Here I have been working on the role of essential genes in mycobacterial pathogenesis and validating them as potential drug targets. Towards this end, I am currently studying NAD metabolic pathway to identify drug targets by creating conditional knockdowns of specific essential genes. Through a combination of molecular genetic and pharmacological techniques, we intend to develop drugs against novel targets in M. tuberculosis, the most common chronic lung infection in the developing world. This work is supported by the Bill and Melinda Gates Foundation. 

Recent publications:

A genetic strategy to identify targets for the development of drugs that prevent bacterial persistence, Kim JH*, O'Brien KM*, Sharma R, Boshoff HI, Rehren G, Chakraborty S, Wallach JB, Monteleone M, Wilson DJ, Aldrich CC, Barry CE 3rd, Rhee KY, Ehrt S, Schnappinger D, Proc Natl Acad Sci U S A. 2013 Nov 19;110(47):19095-100. doi: 10.1073/pnas.1315860110. Epub 2013 Nov 4. (*Joint first author) 

Cyclic AMP in Mycobacteria:characterization and functional role of the Rv1647 ortholog in Mycobacterium smegmatis, Dass B.M.K.*, Sharma R*, Shenoy A.R., Mattoo R. and Visweswariah S.S., Journal of Bacteriology, 190, No -11, 3824 to 3834(2008). (*Joint first author) 

Characterization of a human SWI2/SNF2 like protein hINO80:Demonstration of catalytic and DNA binding activity,Bakshi R., Mehta A.K., Sharma R, Maiti S., Pasha S. and Brahmachari V., Biochem Biophys Res Comm., 339, 313-320 (2006).

Carolina Trujillo, Ph.D.

Carolina Trujillo


Dr. Carolina Trujillo received her B.S. in Biology, a M. Sc. from Universidad de Antioquia and graduated with a Ph.D. in Microbiology from Boston University (’09).   Her dissertation topic defined a novel interaction between a region of the transmembrane domain of diphtheria toxin and a host cell protein complex that is essential for toxin trafficking inside the cell.  Dr. Trujillo’s observations provided evidence to anticipate similar requirements in the intoxication process of related types of bacterial toxins.  She published several papers on this subject.

Dr. Trujillo is currently conducting post-doctoral training in the laboratory of Dr. Sabine Ehrt at Weill Cornell Medical College.  She is characterizing mechanisms important for virulence ofMycobacterium tuberculosis, including the nutritional requirements essential for establishing and maintaining a chronic infection.  Additionally, Dr. Trujillo contributes to the Ehrt Lab’s efforts to validate new drug targets for tuberculosis treatment.

Selected Publications:

Marrero, J., Trujillo C., Rhee, K.Y. and Ehrt, S. (2013).  Glucose phosphorylation is required for Mycobacterium tuberculosis persistence in mice.  Plos Pathog 9(1):e1003116. Doi:10.1371/journal.ppat.1003116

Blumenthal, A., Trujillo, C., Ehrt, S. and Schnappinger, D. (2010).  Simultaneous analysis of multiple Mycobacterium tuberculosis knockdown mutants in vitro and in vivo. Plos One 5(12):e15667. Doi:10.137/journal.pone.0015667

Trujillo, C. Taylor-Parker, J., Harrison, R., and Murphy, J.R. (2010).  Essential lysine residues within transmembrane helix 1 of diphtheria toxin facilitate COPI binding and catalytic domain entry.  Mol Microb 76 1010-9

Ratts, R., Trujillo, C., vanderSpek, J., Harrison, R., and Murphy, J.R. (2005).  A conserved motif in transmembrane helix 1 of diphtheria toxin mediates catalytic domain delivery to the cytosol. Proc Natl Acad Sci USA 102, 15635-15640 

Julien Vaubourgeix, Ph.D.

Julien Vaubourgeix, Ph.D.


I received my PhD from the University of Toulouse in 2009. During my graduate work, I studied the role of M. tuberculosis's oxygenated mycolic acids in the differentiation of human monocyte-derived macrophages into foamy macrophages that host non-replicating bacilli. The biosynthesis of this lipid subclass requires the activity of a methyltransferase, for which I characterized a bisubstrate inhibitor that mimics its cofactor and its substrate. In August 2009, I joined the Nathan laboratory at Weill Cornell medical College to investigate how M. tuberculosis protects itself from the toxicity of damaged molecules—products of both antibiotics and host-imposed stresses—that can neither be repaired nor degraded. 

Helene Botella, Ph.D.

Helene Botella


I received my PhD from the University of Toulouse, France, in December 2011. During my graduate work, I studied the role of zinc poisoning in the interaction of Mtuberculosis and host cells in Dr. Olivier Neyrolle’s laboratory at the Institute of Pharmacology and Structural Biology.

I joined Dr Sabine Ehrt’s lab in Weill Cornell Medical College in February 2012 to work on proteins involved in stress resistance in M. tuberculosis. My projects focus on understanding the molecular mechanisms used by the bacillus to withstand stresses encountered inside the host during the infection.

Shipra Grover, Ph.D.

Shipra Grover


I am a new postdoctoral associate who joined Dr. Dirk Schnappinger’s laboratory at Department of Microbiology and Immunology, Weill Cornell in April 2014. Prior to arriving at Cornell, I obtained my PhD in Molecular Microbiology from the University of Birmingham, UK under the supervision of Prof. Gurdyal S. Besra. I am currently working on the TresCantos Open Lab project which is a collaborative effort between Schnappinger Lab at Weill Cornell and Tres Cantos Open Lab foundation, Galaxo Smith Kline, Spain.  I am focusing on employing high throughput methods for screening of anti-mycobacterial compounds against the essential genes of mycobacteria and evaluating their potential as drug targets. 

Recent publications:

S. Grover,L. J. Alderwick, A. K. Mishra, A. Bhatt, G.S. Besra, Benzothiazinones mediate killing of Corynebacterianeae by blocking decaprenyl phosphate recycling involved in cell wall biosynthesis. Journal of Biological Chemistry 2014, 289, 6177-6187 

Meike Baumgart, Kerstin Luder, Shipra Grover, Cornelia Gätgens , Gurdyal S. Besra, Julia Frunzke, IpsA, a novel LacI-type regulator, is required for inositol-1 derived lipid formation in Corynebacteria and Mycobacteria. BMC Biology 2013, 11:122  

S. Grover*, M. Jankute*, A. K. Rana, G. S. Besra, Arabinogalactan and lipoarabinomannan biosynthesis: structure, biogenesis and their potential as drug targets. Future Microbiol  2012 Jan;7(1):129-47.

S. Grover*, M. Jankute*, H. Birch, G.S. Besra, Genetics of Arabinogalactan and Lipoarabinomannan biosynthesis. Molecular Genetics of Mycobacteria Second Ed. ASM Press. (Accepted, in press)


Claire Healy, Ph.D.

Claire Healy


I obtained my B.A. (moderatorship in Microbiology) at Trinity College Dublin, Ireland. Following that, I obtained my PhD at University College Dublin, Ireland as part of the Thematic PhD programme in Infection Biology, under the supervision of Prof. Stephen Gordon.  During my doctoral research I carried out functional and regulatory analyses of a virulence-associated methyltransferase in the Mycobacterium tuberculosis complex. 

I joined the lab of Dr Sabine Ehrt in June 2014 as a Postdoctoral Associate to investigate genes of unknown function which are critical for M. tuberculosis survival in vitro and during infection, and also to investigate persistence of M. tuberculosis with the aim of establishing a new mouse model of paucibacillary persistence.

Jeanette Sutherland, Ph.D.

Jeanette Sutherland


Jeanette Sutherland completed her Ph.D. in Biochemistry and Molecular Biology at New York Medical College. She studied the repair mechanism of stabilized bacterial topoisomerase I cleavage complexes as part of an overall strategy to develop antibacterial drugs targeting topoisomerase I. 

She joined the Holloman lab in July of 2011 and is currently working on how homologous recombination functions in DNA repair to maintain genomic stability.

Recent Publications:

Kojic, M, Sutherland JH, Pérez-Martín J, and Holloman WK. (2013). Initiation of meiotic recombination in Ustilago maydis. Genetics. 195(4):1231-40.

Liu IF, Sutherland JH, Cheng B, and Tse-Dinh, YC. (2011). Topoisomerase I function during E. coli response to antibiotics and stress enhances cell killing from stabilization of its cleavage complex. J. Antimicrob. Chem. 66(7):1518-24.

Sutherland JH and Tse-Dinh YC. (2010). Analysis of RuvABC and RecG involvement in E. coli response to covalent topoisomerase-DNA complex. J Bacteriol. 192(17):4445-4451.

Divya Tiwari, Ph.D.

Divya Tiwari


Microbiology fascinated me from my biology class in high school and that drive took me a long journey in this field. I received my B.Sc (Microbiology) and M.Sc (Microbiology) from Ravishankar Shukla University, Raipur, India. My pursuit for science brought me to New Delhi, India where I spent the next 5 years of my life at National Institute of Immunology and received a Ph.D degree from Jawahar lal Nehru University New Delhi. My PhD research involved studying a novel signaling mechanism in Mycobacterium tuberculosis involving serine threonine protein kinases, a newly discovered protein entity in the pathogen.

I joined Weill Cornell Medical College in December 2009 and have been working with Dr. Dirk Schnappinger in studying the functionality of essential genes in Mycobacterium tuberculosis with a goal of targeting them for developing novel drug targets for tuberculosis therapy. I have been working on a project that involves an in depth study of biotin metabolism in Mycobacterium tuberculosis using molecular genetic approaches and characterizing inhibitors against enzymes in this pathway.

Rajesh Ringe, Ph.D.

Rajesh Ringe


I received my PhD from Pune University, India in late 2012 and after that came to New York, USA the same year to do postdoctoral research in the laboratory of Prof John Moore. Here I am working on HIV-1 trimeric glycoprotein antigen toward a goal to make a vaccine candidate that is aimed to induce neutralizing antibodies against HIV-1 as a protective immunity.

Recent Publications:

Ringe RP, Sanders RW, Yasmeen A, Kim HJ, Lee JH, Cupo A, Korzun J, Derking R, van Montfort T, Julien JP, Wilson IA, Klasse PJ, Ward AB, Moore JP. Cleavage strongly influences whether soluble HIV-1 envelope glycoprotein trimers adopt a native-like conformation. Proc Natl Acad Sci U S A. 2013; 110:18256-61. 

Yasmeen A, Ringe R, Derking R, Cupo A, Julien JP, Burton DR, Ward AB, Wilson IA, Sanders RW, Moore JP, Klasse PJ. Differential binding of neutralizing and non-neutralizing antibodies to native-like soluble HIV-1 Env trimers, uncleaved Env proteins, and monomeric subunits. Retrovirology. 2014, 11:41 

Ringe R, Bhattacharya J. Preventive and therapeutic applications of neutralizing antibodies to Human Immunodeficiency Virus Type 1 (HIV-1). Ther Adv Vaccines. 2013; 1:67-80

Alexandre Gouzy, Ph.D.

Alexandre Gouzy


Alexandre Gouzy obtained his Ph.D. in microbiology from the University of Toulouse, France, in December 2013. During his Ph.D., he studied the mechanisms used by Mycobacterium tuberculosis to exploit nitrogen during infection in Dr. Olivier Neyrolle’s laboratory at the Institute of Pharmacology and Structural Biology. He is now a postdoctoral fellow in the laboratory of Sabine Ehrt at Weill Cornell Medical College and is funded by the Fondation pour la Recherche Médicale (FRM).

Thulasi Warrier, Ph.D.

Thulasi Warrier


I grew up in Kerala, also called God’s own country, in the southern tip of India. My training as a microbiologist began during my master’s, which I earned from BITS-Pilani in India, and continued in graduate school in MPIIB in Berlin, wherein my thesis was focused on characterizing a class of anti-mycobacterial compounds. I joined the Nathan lab in 2010 as a postdoctoral fellow and have since been studying the biology of Mycobacterium tuberculosis when it is in a ‘non-replicating’ state. I am involved in projects aimed towards identifying new chemical moieties that inhibit mycobacterial survival when exposed to one or more of host-relevant stresses that induce the bacteria to become non-replicating. Characterization of these compounds will lead us to potential novel leads for drug discovery and/or target pathways that will contribute towards treatment shortening regimens for tuberculosis.

Uchechi Ukaegbu, Ph.D.


I received my PhD in Biological Sciences from Northwestern University in the Spring of 2009.  My graduate research was focused on using biochemical and structural methods (x-ray crystallography) to understand the regulation of methane monooxygenase in the methanotroph, Methylococcus capsulatus (Bath).  In October 2009, I joined Deitsch Laboratory in the Dept. of Microbiology and Immunology at Weill Medical College of Cornell University to investigate some of the epigenetic mechanisms that underlie malaria virulence in Plasmodium falciparum.

Swapna Ganduri, Ph.D.


Biography: I graduated with a PhD from Indian Institute of Science (IISc), Bangalore, India in 2011. For my doctoral thesis, I worked on understanding the mechanism of activation of bacteriophage Mu late genes by transcription activator protein C. Subsequent to my PhD, I joined Albert Einstein College of Medicine, NY as a postdoctoral associate where I was involved in deciphering the role of Universal Stress Protein (USP Rv2623) and a predicted ABC transporter in establishing latent infection by Mycobacterium tuberculosis.  Presently, in Dr. Neal Lue’s lab at Weill Cornell, I am investigating the mechanisms of primase-polα regulation by CST complex at Telomeres.

 Recent Publications:

 Kundu PP, Bhowmick T, Swapna G, Pavan Kumar G.V., Nagaraja V, Narayana C. (2014) Allosteric transition induced by Mg²⁺ ion in a transactivator monitored by SERS.  J Phys Chem B. 118 : 5322-30

 Karambelkar S, Swapna G and Nagaraja V. (2012) Silencing of toxic gene expression by Fis. Nucleic Acids Res.40:4358-4367

Swapna G, Chakraborty A, Kumari V, Sen R, Nagaraja,V. (2011) Mutations in the β¢ subunit of E.coli RNA Polymerase perturb the activator polymerase functional interaction required for promoter clearance. Mol Microbiol.80:1169-85




Contact Information

Microbiology and Immunology Weill Cornell Medical College 1300 York Avenue, Box 62 New York, NY 10065 Phone: (212) 746-6505 Fax: (212) 746-8587