Rapid and strain-specific resistance evolution of Staphylococcus aureus against inhibitory molecules secreted by Pseudomonas aeruginosa

Pseudomonas aeruginosa and Staphylococcus aureus frequently occur together in polymicrobial infections, and there is evidence that their interactions negatively affect disease outcome in patients. At the molecular level, interactions between the two bacterial taxa are well-described, with P. aeruginosa usually being the dominant species suppressing S. aureus through a variety of inhibitory molecules. However, in polymicrobial infections, the two species interact over prolonged periods of time, and S. aureus might evolve resistance against inhibitory molecules deployed by P. aeruginosa. Here, we used experimental evolution to test this hypothesis by exposing three different S. aureus strains (Cowan I, 6850, JE2) to the growth-inhibitory supernatant of P. aeruginosa PAO1 over 30 days. We found that all three S. aureus strains rapidly evolved resistance against inhibitory molecules and show that (i) adaptations were strain-specific; (ii) resistance evolution affected the expression of virulence traits; and (iii) mutations in membrane transporters were the most frequent evolutionary targets. Our work indicates that adaptations of S. aureus to co-infecting pathogens could increase virulence and decrease antibiotic susceptibility, because both virulence traits and membrane transporters involved in drug resistance were under selection. Thus, pathogen co-evolution could exacerbate infections and compromise treatment options

La danza escolar: Orientaciones didácticas basadas en la inteligencia emocional en estudiantes del grado noveno de la Institución Educativa Municipal Santiago Pérez de Zipaquirá

145 Páginas.La investigación “Danza escolar: Orientaciones didácticas basadas en la inteligencia emocional, en estudiantes de grado noveno de la Institución Educativa Municipal Santiago Pérez de Zipaquirá” realizada en el marco de la maestría en pedagogía en la Universidad de La Sabana, evidencia la importancia que tiene la danza escolar como un elemento constitutivo en el desarrollo integral de los educandos. Se concibe la danza escolar como un área educativa que optimiza la interacción interpersonal e intrapersonal del individuo, coadyuvando en la generación de: autocontrol, motivación, empatía, autoconocimiento y habilidades sociales, lo cual se puede sintetizar en la estimulación y desarrollo de la inteligencia emocional, a través de la vivencia corporal. Esta investigación se encamina a fortalecer los elementos anteriormente mencionados a través del diseño y aplicación de propuestas didácticas, donde los educandos puedan canalizar la energía positiva y negativa generada por las realidades sociales. Teniendo en cuenta que cada persona es un universo aparte con diferentes fortalezas y habilidades que deben tener cabida en la escuela, se hace conveniente fundamentar esta investigación teóricamente desde las inteligencias Múltiples de Howard Gardner y los postulados de Daniel Goleman, sobre la inteligencia emocional. Es una investigación cualitativa con un alcance descriptivo- e interpretativo, en el cual se utiliza un diseño de investigación acción- reflexión, aplicado a los escolares de grado noveno del colegio Santiago Pérez de Zipaquirá. ​

Rapid and strain-specific resistance evolution of StaphylococcusaureuStaphylococcus aureus against inhibitory molecules secreted by PseudomonasaeruginosaPseudomonas aeruginosa

Pseudomonas aeruginosa and Staphylococcus aureus frequently occur together in polymicrobial infections, and there is evidence that their interactions negatively affect disease outcome in patients. At the molecular level, interactions between the two bacterial species are well-described, with P. aeruginosa usually being the dominant species suppressing S. aureus through a variety of inhibitory molecules. However, in chronic infections the two species interact over prolonged periods of time, and S. aureus might be able to evolve resistance against inhibitory molecules deployed by P. aeruginosa. Here, we used experimental evolution to test this hypothesis by exposing three different S. aureus strains (Cowan I, 6850, and JE2) to the growth-inhibitory supernatant of P. aeruginosa PAO1 over 30 days. Prior to evolution, we found that S. aureus strains were inhibited by secreted compounds regulatorily controlled by the Pseudomonas quinolone signal quorum-sensing system. Following evolution, inhibitory effects were significantly attenuated, and we observed that adaptations were S. aureus strain specific and involved the upregulation of virulence traits such as staphyloxanthin production and the formation of small colony variants. At the genetic level, mutations in membrane transporters (known to be involved in antibacterial uptake) were the most frequent evolutionary targets. Our work indicates that adaptations of S. aureus to P. aeruginosa occurs rapidly and affect both virulence trait expression and membrane transporter functionality. Thus, pathogen evolution could promote species co-existence and complicate treatment options in infections

Whole transcriptome analysis of the poultry red mite Dermanyssus gallinae (De Geer, 1778)

Although the poultry red mite Dermanyssus gallinae (De Geer, 1778) is the major parasitic pest in poultry farming causing substantial economic losses every year, nucleotide data are rare in the public databases. Therefore, de novo sequencing covering the transcriptome of D. gallinae was carried out resulting in a dataset of 232097 singletons and 42130 contiguous sequences (contigs) which were subsequently clustered into 24140 isogroups consisting of 35788 isotigs. After removal of sequences possibly originating from bacteria or the chicken host, 267464 sequences (231657 singletons, 56 contigs and 35751 isotigs) remained, of which 10·3% showed homology to proteins derived from other organisms. The most significant Blast top-hit species was the mite Metaseiulus occidentalis followed by the tick Ixodes scapularis. To gain functional knowledge of D. gallinae transcripts, sequences were mapped to Gene Ontology terms, Kyoto Encyclopedia of Gene and Genomes (KEGG) pathways and parsed to InterProScan. The transcriptome dataset provides new insights in general mite genetics and lays a foundation for future studies on stage-specific transcriptomics as well as genomic, proteomic, and metabolomic explorations and might provide new perspectives to control this parasitic mite by identifying possible drug targets or vaccine candidates. It is also worth noting that in different tested species of the class Arachnida no 28S rRNA was detectable in the rRNA profile, indicating that 28S rRNA might consists of two separate, hydrogen-bonded fragments, whose (heat-induced) disruption may led to co-migration with 18S rRN

Orbital Separation Amplification in Fragile Binaries with Evolved Components

The secular stellar mass-loss causes an amplification of the orbital separation in fragile, common proper motion, binary systems with separations of the order of 1000 A.U. In these systems, companions evolve as two independent coeval stars as they experience negligible mutual tidal interactions or mass transfer. We present models for how post-main sequence mass-loss statistically distorts the frequency distribution of separations in fragile binaries. These models demonstrate the expected increase in orbital seapration resulting from stellar mass-loss, as well as a perturbation of associated orbital parameters. Comparisons between our models and observations resulting from the Luyten survey of wide visual binaries, specifically those containing MS and white-dwarf pairs, demonstrate a good agreement between the calculated and the observed angular separation distribution functions.Comment: 37 pages, 13 figure

Symptom-based stratification of patients with primary Sjögren's syndrome: multi-dimensional characterisation of international observational cohorts and reanalyses of randomised clinical trials

Background Heterogeneity is a major obstacle to developing effective treatments for patients with primary Sjögren's syndrome. We aimed to develop a robust method for stratification, exploiting heterogeneity in patient-reported symptoms, and to relate these differences to pathobiology and therapeutic response. Methods We did hierarchical cluster analysis using five common symptoms associated with primary Sjögren's syndrome (pain, fatigue, dryness, anxiety, and depression), followed by multinomial logistic regression to identify subgroups in the UK Primary Sjögren's Syndrome Registry (UKPSSR). We assessed clinical and biological differences between these subgroups, including transcriptional differences in peripheral blood. Patients from two independent validation cohorts in Norway and France were used to confirm patient stratification. Data from two phase 3 clinical trials were similarly stratified to assess the differences between subgroups in treatment response to hydroxychloroquine and rituximab. Findings In the UKPSSR cohort (n=608), we identified four subgroups: Low symptom burden (LSB), high symptom burden (HSB), dryness dominant with fatigue (DDF), and pain dominant with fatigue (PDF). Significant differences in peripheral blood lymphocyte counts, anti-SSA and anti-SSB antibody positivity, as well as serum IgG, κ-free light chain, β2-microglobulin, and CXCL13 concentrations were observed between these subgroups, along with differentially expressed transcriptomic modules in peripheral blood. Similar findings were observed in the independent validation cohorts (n=396). Reanalysis of trial data stratifying patients into these subgroups suggested a treatment effect with hydroxychloroquine in the HSB subgroup and with rituximab in the DDF subgroup compared with placebo. Interpretation Stratification on the basis of patient-reported symptoms of patients with primary Sjögren's syndrome revealed distinct pathobiological endotypes with distinct responses to immunomodulatory treatments. Our data have important implications for clinical management, trial design, and therapeutic development. Similar stratification approaches might be useful for patients with other chronic immune-mediated diseases. Funding UK Medical Research Council, British Sjogren's Syndrome Association, French Ministry of Health, Arthritis Research UK, Foundation for Research in Rheumatology

Pathophysiological pro-inflammatory and pain-inducing mechanisms in degenerative intervertebral discs

The intervertebral disc (IVD) is thought to be the source of specific back pain as it suffers prominent age-related (degenerative) alterations. A precarious nutrition can cause serious cellular and tissue stress altering the phenotype of IVD cells and their embedding extracellular matrix (ECM). These alterations can be mediated partly by oxidative stress which involves post-translational protein modifications at cellular and ECM level in the IVD. Such modifications include the deposition of advanced glycation end-products (AGE) and tyrosine nitration mediated by the highly oxidising agent peroxynitrite. Their presence or accumulation can potentially affect a vast number of cellular processes ranging from pro-inflammatory signaling cascades to a disruption in tissue homeostasis. Nuclear factor κB (NF-κB) is a transcription factor that regulates the expression of hundreds of target genes in response to numerous stimuli. However, aberrant regulation of NF-κB is associated to many inflammatory and degenerative diseases. The aim of this thesis was to elucidate the physiological impact of oxidative stress in terms of AGE and tyrosine nitration in cells from the centre of the IVD, the nucleus pulposus (NP). Both AGE and tyrosine nitration induced nuclear translocation of the large subunit of NF-κB i.e. p65(RelA) in NP cells. The activated targeted genes varied according to the stimuli; AGE induced MMP-13 expression implying a role in matrix remodelling, whereas peroxynitrite as the source of tyrosine nitration induced a pro-inflammatory response involving a prolonged p65(RelA) nuclear shuttling. Taken together, these results suggest a putative implication of both, AGE and peroxynitrite, as the source of tyrosine nitration, in the age-related changes of the IVD. Die Bandscheibe durchläuft mit zunehmendem Alter degenerative Veränderungen, die an der Entstehung von Rückenschmerzen beteiligt zu sein scheinen. Die schlechte Ernährung in der Bandscheibe kann schwerwiegenden Stress in Zellen und Gewebe auslösen, der zu Veränderungen im Phänotyp der Zellen und in der extrazellulären Matrix führen kann. Diese Veränderungen können auf oxidativem Stress basieren und zu posttranslationalen Proteinmodifikationen in Zellen und Matrix führen, z.B. zur Bildung von Advanced Glycation End Products (AGE) oder zur Nitrierung von Tyrosin durch Peroxynitrit. Die Anreicherung dieser Produkte kann u.a. eine proinflammatorische Kaskade aktivieren oder das Gleichgewicht im Gewebeumbau stören. Der nukleare Faktor kB (NF-kB) ist ein Transkriptionsfaktor, der die Expression vieler Gene reguliert und mit einer Vielzahl inflammatorischen und degenerativer Erkrankungen verknüpft ist. Das Ziel dieser Doktorarbeit war es aufzuklären, welche physiologischen Auswirkungen oxidativer Stress (und damit das Vorkommen von AGE und die Nitrierung von Tyrosin) auf die Zellen der inneren Bandscheibenregion (Nukleus Pulposus) hat. Sowohl das Vorkommen von AGE, als auch die Nitrierung von Tyrosin führte in den Zellen des Nukleus Pulposus zur nuklearen Translokation der grossen Untereinheit von Nf-kB (= p65 = RelA). Die aktivierten Zielgene variierten hierbei je nach Stimuli: AGE induzierte die Genexpression von MMP-13 (was auf eine Bedeutung im Matrixumbau hindeutet), während Peroxynitrit eine proinflammatorische Reaktion verursachte, die mit einer anhaltender Verschiebung von p65 in den Zellkern einherging. Dies Ergebnisse zeigen, dass sowohl AGE als auch Peroxynitrit in der altersbedingten Veränderung der Bandscheibe eine Rolle spielen könnte