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Cuernavaca, Mexico

Ibarra J.A.,University of South Florida | Ibarra J.A.,National Polytechnic Institute of Mexico | Perez-Rueda E.,Av University 2001 | Carroll R.K.,University of South Florida | Shaw L.N.,University of South Florida
BMC Genomics | Year: 2013

Background: Staphylococcus aureus is a widely distributed human pathogen capable of infecting almost every ecological niche of the host. As a result, it is responsible for causing many different diseases. S. aureus has a vast array of virulence determinants whose expression is modulated by an intricate regulatory network, where transcriptional factors (TFs) are the primary elements. In this work, using diverse sequence analysis, we evaluated the repertoire of TFs and sigma factors in the community-associated methicillin resistant S. aureus (CA-MRSA) strain USA300-FPR3757.Results: A total of 135 TFs and sigma factors were identified and classified into 36 regulatory families. From these around 43% have been experimentally characterized to date, which demonstrates the significant work still at hand to unravel the regulatory network in place for this important pathogen. A comparison of the TF repertoire of S. aureus against 1209 sequenced bacterial genomes was carried out allowing us to identify a core set of orthologous TFs for the Staphylococacceae, and also allowing us to assign potential functions to previously uncharacterized TFs. Finally, the USA300 TFs were compared to those in eleven other S. aureus strains including: Newman, COL, JH1, JH9, MW2, Mu3, Mu50, N315, RF122, MRSA252 and MSSA476. We identify conserved TFs among these strains and suggest possible regulatory interactions.Conclusions: The analysis presented herein highlights the complexity of regulatory networks in S. aureus strains, identifies key conserved TFs among the Staphylococacceae, and offers unique insights into several as yet uncharacterized TFs. © 2013 Ibarra et al; licensee BioMed Central Ltd.

Moreno A.,Av University 2001 | Damian-Almazo J.Y.,Av University 2001 | Miranda A.,Av University 2001 | Saab-Rincon G.,Av University 2001 | And 2 more authors.
Enzyme and Microbial Technology | Year: 2010

The capacity of Amy A, a α-amylase from the hyperthermophilic bacteria Thermotoga maritima to carry out transfer reactions in addition to hydrolysis was investigated. Amy A is a saccharifying enzyme that catalyzes the hydrolysis of internal α-1,4 linkages of glucose polymers generating low molecular weight products (G1-G7); however, in the long term it is capable of producing glucose and maltose exclusively. It was shown that Amy A is able to transform maltose to higher molecular weight oligosaccharides like maltoheptaose, through a combination of transfer and hydrolysis reactions: the fact that the enzyme can use maltose to generate higher molecular weight products is an almost unique property among α-amylases, with neotrehalose as one of the products of the transglucosylation activity. Amy A is also capable of efficiently performing alcoholysis reactions from starch and maltodextrins to methanol and butanol, generating alkyl-glycosides. This is the first report in the scientific literature concerning the synthesis of neotrehalose by an α-amylase. © 2009 Elsevier Inc.

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