Klebsiella pneumoniae triggers a cytotoxic effect on airway epithelial cells

<p>Abstract</p> <p>Background</p> <p><it>Klebsiella pneumoniae </it>is a capsulated Gram negative bacterial pathogen and a frequent cause of nosocomial infections. Despite its clinical relevance, little is known about the features of the interaction between <it>K. pneumoniae </it>and lung epithelial cells on a cellular level, neither about the role of capsule polysaccharide, one of its best characterised virulence factors, in this interaction.</p> <p>Results</p> <p>The interaction between <it>Klebsiella pneumoniae </it>and cultured airway epithelial cells was analysed. <it>K. pneumoniae </it>infection triggered cytotoxicity, evident by cell rounding and detachment from the substrate. This effect required the presence of live bacteria and of capsule polysaccharide, since it was observed with isolates expressing different amounts of capsule and/or different serotypes but not with non-capsulated bacteria. Cytotoxicity was analysed by lactate dehydrogenase and formazan measurements, ethidium bromide uptake and analysis of DNA integrity, obtaining consistent and complementary results. Moreover, cytotoxicity of non-capsulated strains was restored by addition of purified capsule during infection. While a non-capsulated strain was avirulent in a mouse infection model, capsulated <it>K. pneumoniae </it>isolates displayed different degrees of virulence.</p> <p>Conclusion</p> <p>Our observations allocate a novel role to <it>K. pneumoniae </it>capsule in promotion of cytotoxicity. Although this effect is likely to be associated with virulence, strains expressing different capsule levels were not equally virulent. This fact suggests the existence of other bacterial requirements for virulence, together with capsule polysaccharide.</p

Efectos conductuales y modulación de la síntesis de monoaminas y de la vía de quinasas mitogénicas en cerebro de rata tras tratamientos con cannabinoides y etanol

A pesar de que el uso del cannabis y el alcohol como sustancias psicoactivas es muy antiguo y que su uso como drogas recreacionales está muy extendido, los mecanismos a través de los cuales producen sus efectos psicoactivos se han empezado a conocer hace relativamente poco tiempo. En la presente tesis se estudia como afectan distintos tratamientos sistémicos, tanto con etanol como con distintos compuestos cannabinoides, simultáneamente sobre la síntesis de las distintas monoaminas en diferentes regiones cerebrales de rata. Además, se analizó como afectaban estos tratamientos a los distintos componentes de la vía de señalización intracelular de las MAPK en la corteza frontal de rata. Se realizaron distintos tratamientos agudos con estos compuestos así como tratamientos a más largo plazo (crónicos) y además se estudiaron estos parámetros durante el llamado síndrome de abstinencia que aparece una vez que se detiene esta administración crónica

Significance of tagl and mfd genes in the virulence of non-typeable Haemophilus infl uenzae

Non-typeable Haemophilus infl uenzae (NTHi) is an opportunist pathogen well adapted to the human upper respiratory tract and responsible for many respiratory diseases. In the human airway, NTHi is exposed to pollutants, such as alkylating agents, that damage its DNA. In this study, we examined the signifi cance of genes involved in the repair of DNA alkylation damage in NTHi virulence. Two knockout mutants, tagI and mfd, encoding N3methyladenine-DNA glycosylase I and the key protein involved in transcription-coupled repair, respectively, were constructed and their virulence in a BALB/c mice model was examined. This work shows that N3-methyladenine-DNA glycosylase I is constitutively expressed in NTHi and that it is relevant for its virulence. [Int Microbiol 2014; 17(3):159-164]Keywords: Haemophilus infl uenzae &middot; alkylating agents &middot; virulence &middot; genes tagI and mf

Dissection of Host Cell Signal Transduction during Acinetobacter baumannii – Triggered Inflammatory Response

Infected airway epithelial cells up-regulate the expression of chemokines, chiefly IL-8, and antimicrobial molecules including β-defensins (BD). Acinetobacter baumannii is a cause of hospital-acquired pneumonia. We examined whether A. baumannii induced the expressions of IL-8 and BD2 by airway epithelial cells and the receptors implicated in bacterial detection. A549 and human primary airway cells released IL-8 upon infection. A. baumannii-infected cells also increased the expression of BD2 which killed A. baummannii strains. IL-8 induction was via NF-κB and mitogen-activated kinases p38 and p44/42-dependent pathways. A. baumannii engaged Toll-like receptor (TLR) 2 and TLR4 pathways and A549 cells could use soluble CD14 as TLRs co-receptor. A. baumannii lipopolysaccharide stimulated IL-8 release by A549 cells and sCD14 facilitated the recognition of the lipopolysaccharide. Mass spectrometry analysis revealed that A. baumannii lipid A structure matches those with endotoxic potential. These results demonstrate that airway epithelial cells produce mediators important for A. baumannii clearance

Telomere length alterations in microsatellite stable colorectal cancer and association with the immune response

Telomeres are repetitive sequences (TTAGGG) located at the end of chromosomes. Telomeres progressively shorten with each cell replication cycle, ultimately leading to chromosomal instability and loss of cell viability. Telomere length anomaly appears to be one of the earliest and most prevalent genetic alterations in malignant transformation. Here we aim to estimate telomere length from whole-exome sequencing data in colon tumors and normal colonic mucosa, and to analyze the potential association of telomere length with clinical factors and gene expression in colon cancer. Reads containing at least five repetitions of the telomere sequence (TTAGGG) were extracted from the raw sequences of 42 adjacent normal-tumor paired samples. The number of reads from the tumor sample was normalized to build the Tumor Telomere Length Ratio (TTLR), considered an estimation of telomere length change in the tumor compared to the paired normal tissue. We evaluated the associations between TTLR and clinical factors, gene expression and copy number (CN) aberrations measured in the same tumor samples. Colon tumors showed significantly shorter telomeres than their paired normal samples. No significant association was observed between TTLR and gender, age, tumor location, prognosis, stromal infiltration or molecular subtypes. The functional gene set enrichment analysis showed pathways related to immune response significantly associated with TLLR. By extracting a relative measure of telomere length from whole-exome sequencing data, we have assessed that colon tumor cells predominantly shorten telomeres, and this alteration is associated with expression changes in genes related to immune response and inflammation in tumor cells

Aberrant gene expression in mucosa adjacent to tumor reveals a molecular crosstalk in colon cancer

Background: A colorectal tumor is not an isolated entity growing in a restricted location of the body. The patient's gut environment constitutes the framework where the tumor evolves and this relationship promotes and includes a complex and tight correlation of the tumor with inflammation, blood vessels formation, nutrition, and gut microbiome composition. The tumor influence in the environment could both promote an anti-tumor or a pro-tumor response. Methods: A set of 98 paired adjacent mucosa and tumor tissues from colorectal cancer (CRC) patients and 50 colon mucosa from healthy donors (246 samples in total) were included in this work. RNA extracted from each sample was hybridized in Affymetrix chips Human Genome U219. Functional relationships between genes were inferred by means of systems biology using both transcriptional regulation networks (ARACNe algorithm) and protein-protein interaction networks (BIANA software). Results: Here we report a transcriptomic analysis revealing a number of genes activated in adjacent mucosa from CRC patients, not activated in mucosa from healthy donors. A functional analysis of these genes suggested that this active reaction of the adjacent mucosa was related to the presence of the tumor. Transcriptional and protein-interaction networks were used to further elucidate this response of normal gut in front of the tumor, revealing a crosstalk between proteins secreted by the tumor and receptors activated in the adjacent colon tissue; and vice versa. Remarkably, Slit family of proteins activated ROBO receptors in tumor whereas tumor-secreted proteins transduced a cellular signal finally activating AP-1 in adjacent tissue. Conclusions: The systems-level approach provides new insights into the micro-ecology of colorectal tumorogenesis. Disrupting this intricate molecular network of cell-cell communication and pro-inflammatory microenvironment could be a therapeutic target in CRC patient

Elasmobranch spatial segregation in the western Mediterranean

Basic information on the distribution and habitat preferences of ecologically important species is essential for their management and protection. This study focuses on the depth related trends and the geographic patterns that shape the community of the elasmobranch species in the Balearic Islands (Mediterranean Sea) using data collected from 2001 to 2009. Non-metric Multi-Dimensional Scaling (MDS) ordination was used to detect zonation patterns in the community. Generalized Additive Models (GAMs) were applied to analyse spatial and temporal variation in elasmobranch community descriptors (abundance, biomass, mean fish weight, number of species and diversity), as well as the abundance and mean length of the four individual species (S. canicula, G. melastomus, R. clavata, R. miraletus). Depth was the main factor determining the assemblage composition, and the MDS analysis identified four main groups with 60% of the similarity found to correspond to the continental shelf, shelf break, upper slope and middle slope of the surveyed area. GAM analysis identified spatial patterns that were independent of the bathymetric distribution preference. Although depth was a strong predictor for all the analyses performed, the geographic variation in the elasmobranch abundance was also important. The results also show a reduction in the mean length of the elasmobranch species in the areas with high fishing intensity. Our study evidences a clear spatial segregation of the main species throughout the ontogeny because the geographic and bathymetric effects were highly size dependent, with clear differences between the bathymetric distributions of juveniles and adults but no clear spatial overlapping. This study sheds new light on the spatial distribution of the elasmobranch species off the Balearic Islands, which is essential information for protecting marine organisms along with their habitats and promoting ecosystem based managementPublicado

Casos prácticos como herramienta educativa en las asignaturas de fisiología humana

[EN] The education plans of the universities represent a coincidence in the subject of Human Physiology (Physiotherapy, Biology, Biochemistry, Nursing and Medicine degrees), in which teaching for small groups are a good strategy to achieve certain skills that could not be achieved during large groups time. The main methodology followed is the realization of monographic works. During the 2018-2019 academic year, the University of the Balearic Islands awarded a teaching innovation project in which the design and coordination of seminars was proposed through an active learning methodology through the resolution of practical cases that would help students to acquire skills in critical thinking, leadership, emotional intelligence, adaptability and management of new technologies. The students had to solve a supposed clinical case, exposing the normal physiological process and the physiological alteration associated with the proposed case. The results obtained (n = 174 students) indicated an improvement in the acquisition of knowledge (average of 8.2) and in the satisfaction (average of 8.1) obtained by the students, who preferred this methodology to monographic expositions or the use of simulators by computer. In conclusion, the methodology contributed was received with a high degree of satisfaction for its innovative application in the small groups.[ES] Los planes docentes de diversas titulaciones suponen una coincidencia en la asignatura de Fisiología Humana (grados: Fisioterapia, Biología, Bioquímica y Medicina), en los cuales las horas docentes destinadas a grupos pequeños suponen una buena estrategia para alcanzar determinadas competencias que no se podrían alcanzar con grupos grandes. La realización de trabajos monográficos es la principal metodología seguida. Durante el curso 2018/2019, la Universidad de las Islas Baleares concedió un proyecto de innovación docente donde se planteó el diseño y la coordinación de la realización de seminarios mediante una metodología activa de aprendizaje a través de resolución de casos prácticos con el objetivo de adquirir destrezas en pensamiento crítico, liderazgo, inteligencia emocional, adaptabilidad y manejo de las nuevas tecnología. Los alumnos debían resolver un supuesto caso clínico, exponiendo el proceso fisiológico normal y la alteración fisiológica asociada al caso propuesto. Los resultados obtenidos (n=174 alumnos) indicaron una mejora en la adquisición de conocimientos (media de 8,2) y en la satisfacción (media de 8,1)obtenida por parte del alumnado, que prefirió esta metodología a las exposiciones monográficas o el uso de simuladores por ordenador. En conclusión, la metodología aportada fue recibida con alto grado de satisfacción por su aplicación innovadora en los grupos pequeños.Tejada Gavela, S.; Bibiloni Esteva, MDM.; Moranta Mesquida, D.; Esteban Valdés, SC.; Sureda Gomila, A. (2019). Casos prácticos como herramienta educativa en las asignaturas de fisiología humana. En IN-RED 2019. V Congreso de Innovación Educativa y Docencia en Red. Editorial Universitat Politècnica de València. 675-683. https://doi.org/10.4995/INRED2019.2019.10439OCS67568