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Guinane C.M.,Roslin Institute | Guinane C.M.,Teagasc | Penades J.R.,Instituto Valenciano Of Investigaciones Agrarias Cita Ivia | Fitzgerald J.R.,Roslin Institute
Virulence | Year: 2011

Staphylococcus aureus is an important human pathogen that also causes economically important infections of livestock. In a recent paper, we employed a population genomic approach to investigate the molecular basis of ruminant host adaptation by S. aureus. The data suggest that the common pathogenic clone associated with small ruminants originated in humans but has since adapted to its adopted host through a combination of allelic diversification, gene loss and acquisition of mobile genetic elements. In particular, a new subfamily of staphylococcal pathogenicity islands (SaPI) was identified encoding a novel von Willebrand factor-binding protein (vWBP) with ruminant-specific coagu-lase activity. The wide distribution of vWBP-encoding SaPIs among ruminant strains implies an important role in host-adaptation. In the current article we summarize the findings of the paper and comment on the implications of the study for our understanding of the molecular basis of bacterial host adaptation. © 2011 Landes Bioscience. Source

Penades J.R.,Institute Biomedicina Of Valencia | Penades J.R.,CEU Cardenal Herrera University | Donderis J.,Institute Biomedicina Of Valencia | Donderis J.,Research Center Biomedica En Red Of Enfermedades Raras Ciberer | And 4 more authors.
Current Opinion in Microbiology | Year: 2013

Deciphering the molecular mechanisms that control relevant cellular processes is of utmost importance to understand how viruses, prokaryotic and eukaryotic cells work. The diversity of living organisms suggests that there are novel regulators still to be discovered, which may uncover new regulatory paradigms. dUTPases (Duts) are assumed to be ubiquitous enzymes regulating cellular dUTP levels to prevent misincorporation of uracil into DNA. Recently however, Duts have been involved in the control of several relevant cellular processes, including transfer of mobile genetic elements, regulation of the immune system, autoimmunity or apoptosis, suggesting that they perform regulatory functions. This review aims at investigating the unexplored impact of Duts as novel signalling molecules. © 2013 Elsevier Ltd. Source

Quiles-Puchalt N.,Institute Biomedicina Of Valencia Ibv Csic | Quiles-Puchalt N.,Instituto Valenciano Of Investigaciones Agrarias Cita Ivia | Tormo-Mas M.A.,Instituto Valenciano Of Investigaciones Agrarias Cita Ivia | Tormo-Mas M.A.,CEU Cardenal Herrera University | And 9 more authors.
Nucleic Acids Research | Year: 2013

The propagation of bacteriophages and other mobile genetic elements requires exploitation of the phage mechanisms involved in virion assembly and DNA packaging. Here, we identified and characterized four different families of phage-encoded proteins that function as activators required for transcription of the late operons (morphogenetic and lysis genes) in a large group of phages infecting Gram-positive bacteria. These regulators constitute a super-family of proteins, here named late transcriptional regulators (Ltr), which share common structural, biochemical and functional characteristics and are unique to this group of phages. They are all small basic proteins, encoded by genes present at the end of the early gene cluster in their respective phage genomes and expressed under cI repressor control. To control expression of the late operon, the Ltr proteins bind to a DNA repeat region situated upstream of the terS gene, activating its transcription. This involves the C-terminal part of the Ltr proteins, which control specificity for the DNA repeat region. Finally, we show that the Ltr proteins are the only phage-encoded proteins required for the activation of the packaging and lysis modules. In summary, we provide evidence that phage packaging and lysis is a conserved mechanism in Siphoviridae infecting a wide variety of Gram-positive bacteria. © 2013 The Author(s). Source

Mir-Sanchis I.,Instituto Valenciano Of Investigaciones Agrarias Cita Ivia | Martinez-Rubio R.,Instituto Valenciano Of Investigaciones Agrarias Cita Ivia | Martinez-Rubio R.,CEU Cardenal Herrera University | Marti M.,Instituto Valenciano Of Investigaciones Agrarias Cita Ivia | And 7 more authors.
Molecular Microbiology | Year: 2012

Staphylococcus aureus pathogenicity islands (SaPIs) are a group of related 15-17kb mobile genetic elements that commonly carry genes for superantigen toxins and other virulence factors. The key feature of their mobility is the induction of SaPI excision and replication by certain phages and their efficient encapsidation into specific small-headed phage-like infectious particles. Previous work demonstrated that chromosomal integration depends on the SaPI-encoded recombinase, Int. However, although involved in the process, Int alone was not sufficient to mediate efficient SaPI excision from chromosomal sites, and we expected that SaPI excision would involve an Xis function, which could be encoded by a helper phage or by the SaPI, itself. Here we report that the latter is the case. In vivo recombination assays with plasmids in Escherichia coli demonstrate that SaPI-coded Xis is absolutely required for recombination between the SaPI attL and attR sites, and that both sites, as well as their flanking SaPI sequences, are required for SaPI excision. Mutational analysis reveals that Xis is essential for efficient horizontal SaPI transfer to a recipient strain. Finally, we show that the master regulator of the SaPI life cycle, Stl, blocks expression of int and xis by binding to inverted repeats present in the promoter region, thus controlling SaPI excision. © 2012 Blackwell Publishing Ltd. Source

Salvador I.,Instituto Valenciano Of Investigaciones Agrarias Cita Ivia | Cebrian-Serrano A.,Instituto Valenciano Of Investigaciones Agrarias Cita Ivia | Salamone D.,University of Buenos Aires | Silvestre M.A.,Instituto Valenciano Of Investigaciones Agrarias Cita Ivia
Spanish Journal of Agricultural Research | Year: 2011

The aim of this study was to identify the in vitro development stage at which the culture of a single or low number (n = 5 or 10) of oocytes/embryos could impair development in comparison with culture in group (n = 50). In the Experiment 1, it was confirmed that single in vitro embryo production yielded lower cleavage and blastocyst rates than in group (49.4 vs. 83.0%; 0% vs. 37.8%, respectively; p < 0.05). In Experiment 2 and 3, it was observed no effect on embryo development of culturing single or low number of oocytes during maturation and fertilization, respectively. In Experiment 4, it was observed a detrimental effect on blastocyst rate when cultured single or low number of embryos during post-fertilization in vitro culture (2.9; 10.2-10.8; 33.2% in single, low number of embryos (5-10), and controlgrouped, respectively; p < 0.05). In Experiment 5, it was observed that the last part of the culture period (day 3 onwards) seemed to be more affected by the low number of embryos placed in culture. In conclusion, post-fertilization culture, especially on days 3 to 7 after fertilization, seems to be the most important stage for embryo development on single and/or low number (5-10) of embryos culture. Source

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