Brr6 drives the Schizosaccharomyces pombe spindle pole body nuclear envelope insertion/extrusion cycle

Insertion into and release of the cytoplasmic domain of the Schizosaccharomyces pombe spindle pole body from a nuclear envelope fenestra during mitosis requires Brr6

The Neglected Intrinsic Resistome of Bacterial Pathogens

Bacteria with intrinsic resistance to antibiotics are a worrisome health problem. It is widely believed that intrinsic antibiotic resistance of bacterial pathogens is mainly the consequence of cellular impermeability and activity of efflux pumps. However, the analysis of transposon-tagged Pseudomonas aeruginosa mutants presented in this article shows that this phenotype emerges from the action of numerous proteins from all functional categories. Mutations in some genes make P. aeruginosa more susceptible to antibiotics and thereby represent new targets. Mutations in other genes make P. aeruginosa more resistant and therefore define novel mechanisms for mutation-driven acquisition of antibiotic resistance, opening a new research field based in the prediction of resistance before it emerges in clinical environments. Antibiotics are not just weapons against bacterial competitors, but also natural signalling molecules. Our results demonstrate that antibiotic resistance genes are not merely protective shields and offer a more comprehensive view of the role of antibiotic resistance genes in the clinic and in nature

The SUN Protein Mps3 Is Required for Spindle Pole Body Insertion into the Nuclear Membrane and Nuclear Envelope Homeostasis

The budding yeast spindle pole body (SPB) is anchored in the nuclear envelope so that it can simultaneously nucleate both nuclear and cytoplasmic microtubules. During SPB duplication, the newly formed SPB is inserted into the nuclear membrane. The mechanism of SPB insertion is poorly understood but likely involves the action of integral membrane proteins to mediate changes in the nuclear envelope itself, such as fusion of the inner and outer nuclear membranes. Analysis of the functional domains of the budding yeast SUN protein and SPB component Mps3 revealed that most regions are not essential for growth or SPB duplication under wild-type conditions. However, a novel dominant allele in the P-loop region, MPS3-G186K, displays defects in multiple steps in SPB duplication, including SPB insertion, indicating a previously unknown role for Mps3 in this step of SPB assembly. Characterization of the MPS3-G186K mutant by electron microscopy revealed severe over-proliferation of the inner nuclear membrane, which could be rescued by altering the characteristics of the nuclear envelope using both chemical and genetic methods. Lipid profiling revealed that cells lacking MPS3 contain abnormal amounts of certain types of polar and neutral lipids, and deletion or mutation of MPS3 can suppress growth defects associated with inhibition of sterol biosynthesis, suggesting that Mps3 directly affects lipid homeostasis. Therefore, we propose that Mps3 facilitates insertion of SPBs in the nuclear membrane by modulating nuclear envelope composition

Pseudomonas aeruginosa Population Structure Revisited

At present there are strong indications that Pseudomonas aeruginosa exhibits an epidemic population structure; clinical isolates are indistinguishable from environmental isolates, and they do not exhibit a specific (disease) habitat selection. However, some important issues, such as the worldwide emergence of highly transmissible P. aeruginosa clones among cystic fibrosis (CF) patients and the spread and persistence of multidrug resistant (MDR) strains in hospital wards with high antibiotic pressure, remain contentious. To further investigate the population structure of P. aeruginosa, eight parameters were analyzed and combined for 328 unrelated isolates, collected over the last 125 years from 69 localities in 30 countries on five continents, from diverse clinical (human and animal) and environmental habitats. The analysed parameters were: i) O serotype, ii) Fluorescent Amplified-Fragment Length Polymorphism (FALFP) pattern, nucleotide sequences of outer membrane protein genes, iii) oprI, iv) oprL, v) oprD, vi) pyoverdine receptor gene profile (fpvA type and fpvB prevalence), and prevalence of vii) exoenzyme genes exoS and exoU and viii) group I pilin glycosyltransferase gene tfpO. These traits were combined and analysed using biological data analysis software and visualized in the form of a minimum spanning tree (MST). We revealed a network of relationships between all analyzed parameters and non-congruence between experiments. At the same time we observed several conserved clones, characterized by an almost identical data set. These observations confirm the nonclonal epidemic population structure of P. aeruginosa, a superficially clonal structure with frequent recombinations, in which occasionally highly successful epidemic clones arise. One of these clones is the renown and widespread MDR serotype O12 clone. On the other hand, we found no evidence for a widespread CF transmissible clone. All but one of the 43 analysed CF strains belonged to a ubiquitous P. aeruginosa “core lineage” and typically exhibited the exoS+/exoU− genotype and group B oprL and oprD alleles. This is to our knowledge the first report of an MST analysis conducted on a polyphasic data set

TARJETA POSTAL NAVIDEÑA [Material gráfico]

ITALIACopia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201

EPIDEMIOLOGÍA MOLECULAR DE AISLADOS CLÍNICOS DE Pseudomonas aeruginosa EN EL COMPLEJO METROPOLITANO HARMODIO ARIAS MADRID

To study the molecular epidemiology of Pseudomonas aeruginosa, 53 isolates from different anatomic areas from patients of the Complejo Metropolitano Armodio Arias Madrid de la Caja del Seguro Social, were obtained and analyzed. The isolates of P. aeruginosa were obtained during a period of 1 year and were phenotypically identified by biochemical analysis carried out with the API 20NE (Bio Merieux, Brussels, Belgium) and antibiotic sensitivity of the strains as well. Molecular diagnosis was performed using Multiplex-PCR of the pyoverdin receptor genes FPVA. This study showed low specificity of phenotypic tests in use since 39 isolates from a total of 53 could not be identified as P. aeruginosa by using the API 20E system, representing 74% of the strains tested. Differences in susceptibility to antibiotics were found compare to previous studies, especially major changes in the antimicrobial susceptibility profile of quinolones were observed. All isolates were identified with any of the pyoverdin receptor genes. The availability of sequences of the pyoverdin receptor fpvA genes of P. aeruginosa allowed us to standardize a rapid technique for the siderotyping of all the isolated strains. This is extremely important for strains that do not produce pyoverdin, which cannot be detected by conventional culture methods. Our study showed that this test has demonstrated to be specific and rapid, when it was compared with the API 20NE test and the conventional antimicrobial sensitivity tests.    Para el estudio de la epidemiología molecular de Pseudomonas aeruginosa se obtuvieron 53 aislados de diferentes áreas anatómicas de pacientes del Complejo Metropolitano Harmodio Arias Madrid de la Caja del Seguro Social. Los aislados de P. aeruginosa fueron obtenidos durante un período de 1 año y fueron identificados fenotípicamente mediante el perfil bioquímico obtenido con la prueba de API 20NE (Bio Mérieux, Bruselas, Bélgica) y la sensibilidad de las cepas a antibióticos mediante un antibiograma que verificó la sensibilidad a estos. El diagnóstico molecular se realizó utilizando los genes de los receptores de pioverdina FpvA, los cuales fueron amplificados mediante la técnica de Multiplex-PCR. Los resultados en este estudio demostraron la baja sensibilidad de las pruebas fenotípicas ya que 39 aislados de un total de 53 pudieron ser identificados como P. aeruginosa por medio del sistema API 20E representando un 74% de las cepas analizadas. Igualmente mediante los antibiogramas se encontraron diferencias en la susceptibilidad a los agentes antimicrobianos y que reflejan cambios importantes en el perfil de susceptibilidad antimicrobiana a quinolonas. Todos los aislados fueron identificados con algunos de los genes de los receptores de pioverdina. La disponibilidad las secuencias de los receptores de pioverdina fpvA de P. aeruginosa han permitido estandarizar una técnica rápida para el siderotipaje de las cepas y sobre todo para cepas que no producen pioverdina y que por ende no pueden detectarse a través de métodos de cultivo convencionales. Esta técnica en este estudio ha demostrado su mayor especificidad y rapidez, en comparación con la prueba de API 20NE y el antibiograma.&nbsp