[Lcefiec] SEMINARIOS QB-IQUIBICEN- Lunes 25 mar- Anil K Ojha

[Cybele García]

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Estimados Colegas, tenemos el agrado de invitarlos al ciclo 2013 de
Seminarios del Departamento de Química Biológica.

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Lunes 25 de marzo, 13-14 hs- Aula Cardini.

"Role of a dynamic envelope in the adaptive response of mycobacteria: a
perspective from biofilms"

Anil K Ojha, PhD
Assistant Professor
Department of Infectious Diseases and Microbiology
Graduate School of Public Health
University of Pittsburgh


Mycobacteria are made of thick and waxy envelope which undergoes dynamic
structural changes during bacterial growth in both planktonic and in
biofilm forms. The enzymes modulating the structure of the envelope
therefore have important role in mycobacterial adaptation. Our laboratory
has been working on one such enzyme- a hydrolase of trehalose 6,6
dimycolate – called TDM hydrolase (TDMH). TDMH activity is induced under
limiting nutrients to facilitate influx of multiple nutrients in
planktonic as well as biofilm growth. However, such adaptive response
comes at a price, for mycobacteria with elevated hydrolase activity are
more sensitive to stress. We have also gathered evidence that the effects
and counter-effects of TDMH play important role in chronic infection of
Mycobacterium tuberculosis- the
etiologic agent of tuberculosis and the deadliest pathogen known to the
mankind- in immunocompetent host.

Selected publications

- Exposure to a cutinase-like serine esterase triggers rapid lysis of
multiple mycobacterial species. Yang Y, Bhatti A, Ke D, Gonzalez-Juarrero
M, Lenaerts A, Kremer L, Guerardel Y, Zhang P, Ojha AK. J Biol Chem. 2013

-Targeting drug tolerance in mycobacteria: a perspective from
mycobacterial biofilms. Islam MS, Richards JP, Ojha AK. Expert Rev Anti
Infect Ther. 2012
-Growth of Mycobacterium tuberculosis biofilms. Kulka K, Hatfull G, Ojha
AK. J Vis Exp. 2012

-Enzymatic hydrolysis of trehalose dimycolate releases free mycolic acids
during mycobacterial growth in biofilms. Ojha AK, Trivelli X, Guerardel Y,
Kremer L, Hatfull GF. J Biol Chem. 2010

-Growth of Mycobacterium tuberculosis biofilms containing free mycolic
acids and harbouring drug-tolerant bacteria. Ojha AK, Baughn AD, Sambandan
D, Hsu T, Trivelli X, Guerardel Y, Alahari A, Kremer L, Jacobs WR Jr,
Hatfull GF. Mol Microbiol. 2008

-The role of iron in Mycobacterium smegmatis biofilm formation: the
exochelin siderophore is essential in limiting iron conditions for biofilm
formation but not for planktonic growth. Ojha A, Hatfull GF. Mol
Microbiol. 2007

-GroEL1: a dedicated chaperone involved in mycolic acid biosynthesis
during biofilm formation in mycobacteria. Ojha A, Anand M, Bhatt A, Kremer
L, Jacobs WR Jr, Hatfull GF. Cell. 2005

Invita: Mariana Piuri
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Los esperamos!
Adriana De Siervi
Javier Cotignola
Cybele García