Quantitative detection of Staphylococcus aureus, Enterococcus faecalis and Pseudomonas aeruginosa in human oral epithelial cells from subjects with periodontitis and periodontal health

Epithelial cells in oral cavities can be considered reservoirs for a variety of bacterial species. A polymicrobial intracellular flora associated with periodontal disease has been demonstrated in buccal cells. Important aetiological agents of systemic and nosocomial infections have been detected in the microbiota of subgingival biofilm, especially in individuals with periodontal disease. However, non-oral pathogens internalized in oral epithelial cells and their relationship with periodontal status are poorly understood. The purpose of this study was to detect opportunistic species within buccal and gingival crevice epithelial cells collected from subjects with periodontitis or individuals with good periodontal health, and to associate their prevalence with periodontal clinical status. Quantitative detection of total bacteria and Staphylococcus aureus, Pseudomonas aeruginosa and Enterococcus faecalis in oral epithelial cells was determined by quantitative real-time PCR using universal and species-specific primer sets. Intracellular bacteria were visualized by confocal microscopy and fluorescence in situ hybridization. Overall, 33 % of cell samples from patients with periodontitis contained at least one opportunistic species, compared with 15 % of samples from healthy individuals. E. faecalis was the most prevalent species found in oral epithelial cells (detected in 20.6 % of patients with periodontitis, P = 0.03 versus healthy individuals) and was detected only in cells from patients with periodontitis. Quantitative real-time PCR showed that high levels of P. aeruginosa and S. aureus were present in both the periodontitis and healthy groups. However, the proportion of these species was significantly higher in epithelial cells of subjects with periodontitis compared with healthy individuals (P = 0.016 for P. aeruginosa and P = 0.047 for S. aureus). Although E. faecalis and P. aeruginosa were detected in 57 % and 50 % of patients, respectively, with probing depth and clinical attachment level ≥6 mm, no correlation was found with age, sex, bleeding on probing or the presence of supragingival biofilm. The prevalence of these pathogens in epithelial cells is correlated with the state of periodontal disease.

Staphylococcus aureus thiaminase II: oligomerization warrants proteolytic protection against serine proteases

Staphylococcus aureus TenA (SaTenA) is a thiaminase type II enzyme that catalyzes the deamination of aminopyrimidine, as well as the cleavage of thiamine into 4-amino-5-hydroxymethyl-2-methylpyrimidine (HMP) and 5-(2-hydroxyethyl)-4-methylthiazole (THZ), within thiamine (vitamin B1) metabolism. Further, by analogy with studies of Bacillus subtilis TenA, SaTenA may act as a regulator controlling the secretion of extracellular proteases such as the subtilisin type of enzymes in bacteria. Thiamine biosynthesis has been identified as a potential drug target of the multi-resistant pathogen S. aureus and therefore all enzymes involved in the S. aureus thiamine pathway are presently being investigated in detail. Here, the structure of SaTenA, determined by molecular replacement and refined at 2.7 A ° resolution to an R factor of 21.6% with one homotetramer in the asymmetric unit in the orthorhombic space group P212121, is presented. The tetrameric state of wild-type (WT) SaTenA was postulated to be the functional biological unit and was confirmed by small-angle X-ray scattering (SAXS) experiments in solution. To obtain insights into structural and functional features of the oligomeric SaTenA, comparative kinetic investigations as well as experiments analyzing the structural stability of the WT SaTenA tetramer versus a monomeric SaTenA mutant were performed.

Entrevista al Dr. Javier Santaolalla, ingeniero de telecomunicación y fisico español, participante en las investigaciones del boson Higgs en el CERN.

Entrevista a Javier Santaolalla investigador en el experimento del CERN que describió recientemente una nueva partícula: el bosón de Higgs, que trata de explicar el origen de la masa de las partículas elementales. La existencia del bosón de Higgs y su campo asociado intentan explicar la razón de la existencia de masa en las partículas elementales. El 4 de julio de 2012, el CERN anunció la observación de una nueva partícula «consistente con el bosón de Higgs», pero se necesitaría más tiempo y datos para confirmarlo. El 14 de marzo de 2013 el CERN, con dos veces más datos de los que disponía en el anuncio del descubrimiento en julio de 2012, encontraron que la nueva partícula se ve cada vez más como el bosón de Higgs. Javier Santaolalla es ingeniero de telecomunicación por la Universidad de las Palmas de Gran Canaria y licenciado en ciencias físicas por la Universidad Complutense de Madrid. Investigador del CIEMAT (Madrid) y Dr. por esta última universidad en ciencias físicas. El Dr. Javier Santaolalla se encuentra unos días de escala en Las Palmas de Gran Canaria procedente de Brasil y con destino a Ginebra. Le agradecemos cuantas facilidades nos ha proporcionado en la realización de la presente entrevista así como sus aportaciones.

Nuevas investigaciones en torno a los grabados rupestres del Barranco de Balos (Agüimes, Gran Canaria)

[ES] Thirty six years have happened since A. Beltrán carried the first study out in depth of the archaeological area of the Massif of Balos. A study that adheres strictly to this emplacement, without never one alludes to the cultural context of these representations or to the existence of other sets in the same space. The recent studies have made clear not only that the Lomo de los Letreros is not the only rock existing station in this territory but in the same one there is located a nourished representation of places that award to this place an unusual interest to realize an approach to the meaning of this pre-hispanic engravings.