Belen Floriano

Current position at CABD: Associated researcher
Current position at UPO: Full professor

Previous scientific experience:
Molecular biology of filamentous cyanobacteria (IBVF-CSIC)
Antibiotic production regulation in Streptomyces (JIC-BBSRC)
Bacteriocin production by lactic acid bacteria (IG-CSIC)
 
 
 

Regulation of biodegradation pathways for aromatic compounds in Gram positive bacteria of environmental interest

Rhodococcus sp strain TFB is a versatile gram positive bacterium able to grow using different aromatic compounds (like tetralin, naphthalene, phthalate, etc.) as carbon and energy sources transforming them to CO2 and water. Since this strain is refractory to genetic analysis, we have made use of a proteomic approach to characterize the metabolic pathways involved in the catabolism of such compounds by analyzing differentially induced proteins in 2D-DIGE gels. Identification of those proteins allowed us to clone and sequence the corresponding genes to study their expression.
Diverse regulatory mechanisms seem to be operating at the same time in this bacterium to control the expression of catabolic genes in response to the presence of the right signal in the medium. Using different approaches, we are characterizing the promoters that drive the transcription of the catabolic genes and the proteins involved in such control in TFB.

 

 

Molecular mechanism of thn genes regulation in Sphingomonas macrogolitabida strain TFA

The success of a bacterium in the environment depends not only on its metabolic versatility but on the regulatory mechanisms that ensure the expression of the catabolic pathways when is really needed. Sphingomonas macrobolitabida strain TFA is a gram negative bacterium able to grow on tetralin (a compound with an alicyclic and an aromatic ring) as carbon and energy sources. Catabolic thn genes are regulated at two different levels: specific induction by tetralin and catabolite repression, a global gene expression control that assures the absence of thn genes expression when a preferential carbon source is present in the medium. Specific tetralin induction relies on a transcriptional regulator (ThnR) whose activity is modulated by a system that “talks” to the metabolic pathway at the same time (see the work of the collaborator Dr Francisca Reyes). In this project we are studying the molecular mechanism by which ThnR acts as transcriptional activator and identifying the elements involved in catabolite repression in TFA.

Lab members & collaborators:

Lab members

PhD students           
Aroa López Sánchez                   
Laura Tomás Gallardo           
Elena Rivas-Marín           
           
Undergraduate student
Alejandro Sarrión Perdigones

Collaborators

Dr Eduardo Santero, CABD-UPO
Dr Francisca Reyes, CABD-UPO
Dr Juan Antonio López, Proteomic Unit-CNIC, Madrid

Five relevant publications:

 

• O. Martínez-Pérez, A. López-Sánchez, F. Reyes-Ramírez, B. Floriano, y E. Santero (2007). Integrated Response to Inducers by Communication between a Catabolic Pathway and Its Regulatory System. Journal of Bacteriology 189:3768-3775.
• J.L. Ruiz-Barba, B. Floriano, A. Maldonado-Barragán y R. Jiménez-Díaz, 2007. Molecular analysis of the 21-kb bacteriocin-encoding plasmid pEF1 from Enterococcus faecium 6T1a. Plasmid, 57:175-181.
• L. Tomás-Gallardo, I. Canosa, E. Santero, E. Camafeita, E. Calvo, J.A. López y B. Floriano (2006). Proteomic and transcriptional characterization of aromatic degradation pathways in Rhodococcus sp. strain TFB. Proteomics 6:119-132.
• O. Martínez-Pérez, E. Moreno-Ruiz, B. Floriano, y E. Santero (2004). Regulation of tetralin biodegradation and identification of genes essential for expression of thn operons. Journal of Bacteriology, 186:6101-6109.
• M.J. Hernáez, B. Floriano, J.J. Rios y E. Santero (2002). Identification of a hydratase and a class II aldolase involved in biodegradation of the organic solvent tetralin. Applied and Environmental Microbiology, 68:4841-4846.