 |
|
 |
|
|
|
|
 RESEARCH Laboratories |
|
 | BIOCHEMISTRY AND GENETICS OF RHIZOBACTERIA |
|
| Ángeles Zorreguieta, Ph.D.
Member of National Research Council (CONICET). |
Professor of Biological Chemistry Department, School of Exact and Natural Sciences, University of Buenos Aires.
Chemistry graduate, School of Exact and Natural Sciences, University of Buenos Aires, 1983
Ph.D. in Chemistry , University of Buenos Aires, 1988
Research Fellow. Laboratory Prof. J. Allan Downie. Genetics Department. John Innes Centre. United Kingdom, 1997-2001
LAB MEMBERS
Daniela M. Russo, Ph.D., Posdoctoral Fellow, CONICET
This e-mail address is being protected from spam bots, you need JavaScript enabled to view it
Lorena Haurigot, graduate student
This e-mail address is being protected from spam bots, you need JavaScript enabled to view it
Fernando Ariel Martín, graduate student
This e-mail address is being protected from spam bots, you need JavaScript enabled to view it
Diana M. Posadas, graduate student
This e-mail address is being protected from spam bots, you need JavaScript enabled to view it
Alfonso Soler Bistué, graduate student
This e-mail address is being protected from spam bots, you need JavaScript enabled to view it
Nicolás Vozza, graduate student
This e-mail address is being protected from spam bots, you need JavaScript enabled to view it
Verónica Ruiz, undergraduate student in Biology, FCEyN, UBA
This e-mail address is being protected from spam bots, you need JavaScript enabled to view it
|
|
|
|
 | RESEARCH INTERESTS |
|
 Mixed Biofilm of the Rhizobium symbiont...
Bacteria respond to environmental changes through the induction of diverse adaptation mechanisms. These mechanisms often require transport of molecules to the extracellular medium not only for proteinic factor secretion but also for the efflux of toxic compounds encountered in the environment. Other more sophisticated adaptation processes culminate with the establishment of a multicelularity, that is, the formation of bacterial communities or “biofilms”. These processes are important for the colonization of a particular niche and for survival in adverse environments. Our group studies different aspects of proteobacteria physiology that contribute to the colonization and survival within diverse habitats. We are interested to establish the molecular basis of adhesion properties between bacteria and biofilm formation, as well as the impact of protein secretion and efflux of toxic compounds on survival in bacteria of Rhizobiaceae group.
Pathogenic bacteria have to overcome not only natural toxic compounds encountered in the host but also other non-natural antimicrobials like antibiotics. We have recently started a collaborative project aimed to study dispersal mechanisms of resistance genes such as the gene encoding for amikacin resistance (aac(6'b)-Ib) and explore possibilities of inactivation of these genes by gene silencing techniques.
carry out studies on proteins secreted by certain related bacteria, such as those that live in symbiosis with certain plants and fix atmospheric nitrogen, others that generate tumours in plants, besides the causing agent of brucellosis. Ultimately, these researches will serve for future vaccine production or for disease diagnosis.
Brucella is an intracellular facultative Gram negative bacteria, responsible of brucellosis in human and animals, a disease that is very difficult to treat and diagnose. Brucella is capable to colonize and survive in the host for prolonged periods. By heterologous genetic approaches and transport assays with fluorescent dyes we demonstrated that B. suis has a ABC-type translocase (ATP binding component)/MFP (membrane fusion protein), which is able to eliminate toxic compounds of different hidrofobicity degree. Besides, deletion mutants analysis and gene expression studies showed that B. suis contains two functional RND (Resistance Nodulation Division)/MFP) translocases. Brucella spp. have one component of the TolC family, named BepC, which would be responsible of translocase recruitment by induction of a transcient efflux channel. Our results suggest that some BepC-dependent efflux processes contribute to B. suis survival and infection.
Rhizobia (close relatives of Brucella spp.) have the ability to establish a symbiosis with legumes and induce nitrogen fixing nodules. By confocal microscopy we showed that GFP-labelled Rhizobium leguminosarum is able to develop in minimal medium a three-dimensional structure or biofilm. The PrsDE system was responsible for secretion of several proteins that partipate in cell-cell interaction, in the attachment to different surfaces and biofilm formation. In addition, the EPS and the O-antigen of the LPS were esential for biofilm formation from the first stages.
In 2004, in collaboration with Dr. M. Tolmasky (Fullerton, U.S.A.) and Drs. M. Galas and A. Petroni (Inst. Malbrán), we started a project with the aim to give insight in some aspects related to the increasing antibiotic resistance in bacterial infections. We are currently studying dissemination mechanisms of antibiotic resistance genes and exploring possible strategies to inactivate these genes. We have recently characterized a clase I- integron (InV117), which includes the blactx-M-2 that encode a broad spectrum β-lactamase and the aac(6')-Ib that encode an aminoglycoside acetyl transferase responsible for inactivation of important antibiotics of the aminoglycoside family. We have found that InV117 is associated with transposition genes such as tnp1696 that makes it potentially able to transpose. |
|
|
|
| RECENT PUBLICATIONS |
|
Torres, P.S, Malamud, F., Rigano, L.A, Russo, D.M., Marano, M.R., Castagnaro, A.P., Zorreguieta, A., Bouarab, K.,Dow, J.M, and Vojnov, A.A.” Controlled synthesis of the DSF cell-cell signal is required for biofilm formation and virulence in Xanthomonas campestris”. (2007) Environmental Microbiology, 9:2101-9
External Guide Sequences Targeting the aac(6’)-Ib mRNA Induce Inhibition of Amikacin Resistance. Alfonso J.C. Soler Bistué, Hongphuc Ha, Renee Sarno, Michelle Don, Angeles Zorreguieta, and Marcelo E. Tolmasky, (2007) Antimicrob. Agents Chemother., 51:1918-25.
Posadas D. M., Martín F. A., Sabio García J., Spera J. M., Delpino M. V., Baldi P., Campos E., Cravero S. L. and Zorreguieta A.. The TolC homologue of Brucella suis is involved in resistance to antimicrobial compounds and virulence. (2007) Infection and Immunity, 75:379-89
Serra D., Bosch A., Russo D. M., Rodríguez M. E., Zorreguieta A., Schmitt J., Naumann D., Yantorno O. Fourier transform infrared spectroscopy and other corroborative techniques. (2007)
Anal Bioanal Chem. 387:1759-67
Russo D. M., Williams A., Edwards A., Posadas D., Finnie C., Dankert M., Downie J. Allan and Zorreguieta A. (2006) Proteins secreted by the PrsD-PrsE system and the acidic EPS are involved in biofilm formation in Rhizobium leguminosarum bv viciae.. Journal of Bacteriology 188: 4474-86
Rinaudi L, Fujishige NA, Hirsch AM, Banchio E, Zorreguieta A, Giordano W. Effects of nutritional and environmental conditions on Sinorhizobium meliloti biofilm formation. (2006) Res. Microbiol. 157: 867-875
Soler Bistué A. J.C., Martin F. A. Petroni A., Faccone D., Galas M., Tolmasky M.E., and Zorreguieta A. (2006). Vibrio cholerae InV117, a class 1 integron harboring aac(6')-Ib and blaCTX-M-2, is linked to transposition genes. Antimicrob Agents Chemother. 50:1903-7. AJCSB y FAM have contributed equally to this work. |
|
|
|
| CURRENT FUNDING |
|
UBACyT 2004-2007 X-245, Universidad de Buenos Aires
CONICET PIP6080, 2005-2006
FONCYT, 2004-2007 PICT 20334, Agencia de Promoción Científica y Tecnológica
|
|
|
|
|
|
|
|
More info
How to get here