Comparative roadmaps of reprogramming and oncogenic transformation identify Bcl11b and Atoh8 as broad regulators of cellular plasticity.

Coordinated changes of cellular plasticity and identity are critical for pluripotent reprogramming and oncogenic transformation. However, the sequences of events that orchestrate these intermingled modifications have never been comparatively dissected. Here, we deconvolute the cellular trajectories of reprogramming (via Oct4/Sox2/Klf4/c-Myc) and transformation (via Ras/c-Myc) at the single-cell resolution and reveal how the two processes intersect before they bifurcate. This approach led us to identify the transcription factor Bcl11b as a broad-range regulator of cell fate changes, as well as a pertinent marker to capture early cellular intermediates that emerge simultaneously during reprogramming and transformation. Multiomics characterization of these intermediates unveiled a c-Myc/Atoh8/Sfrp1 regulatory axis that constrains reprogramming, transformation and transdifferentiation. Mechanistically, we found that Atoh8 restrains cellular plasticity, independent of cellular identity, by binding a specific enhancer network. This study provides insights into the partitioned control of cellular plasticity and identity for both regenerative and cancer biology.

The Type IX Secretion System and Its Role in Bacterial Function and Pathogenesis.

Porphyromonas, Tannerella, and Prevotella species found in severe periodontitis use the Type IX Secretion System (T9SS) to load their outer membrane surface with an array of virulence factors. These virulence factors are then released on outer membrane vesicles (OMVs), which penetrate the host to dysregulate the immune response to establish a positive feedback loop of chronic, inflammatory destruction of the tooth's supporting tissues. In this review, we present the latest information on the molecular architecture of the T9SS and provide mechanistic insight into its role in secretion and attachment of cargo proteins to produce a virulence coat on cells and OMVs. The recent molecular structures of the T9SS motor comprising PorL and PorM as well as the secretion pore Sov, together with advances in the overall interactome, have provided insight into the possible mechanisms of secretion. We propose the presence of PorL/M motors arranged in a circle at the inner membrane with bent periplasmic rotors interacting with the PorN protein. At the outer membrane, we envisage a slide carousel model where the PorN protein is driven around a circular track composed of PorK. Cargo proteins are transported by PorN to PorW and the Sov translocon just as slides are rotated to the projection window. Secreted proteins are proposed to then be shuttled along highways consisting of the PorV shuttle protein to an array of attachment complexes distributed around the cell. The cell surface attachment of cargo is a hallmark of the T9SS, and in Porphyromonas gingivalis and Tannerella forsythia, this attachment is achieved via covalent bonding to a linking sugar synthesized by the Wbp/Vim pathway. The cell-surface attached cargo are enriched on OMVs, which are then released from the cell.

Bilateral deficit in explosive force related to sit-to-stand performance in older postmenopausal women.

The purpose of this study was to determine whether the bilateral deficit (BLD) for maximal voluntary force (MVF) and rate of force development (RFD) influences sit-to-stand in older postmenopausal women. Fourteen women performed unilateral and bilateral maximal voluntary contractions during isometric leg-extension. The MVF and RFD over consecutive 50ms periods (0-50, 50-100 and 100-150ms) after force onset and the time to sit-to-stand test were calculated. There was only a BLD for RFD 0-50ms and 50-100ms. The time of sit-to-stand was moderately correlated to BLD for RFD 0-50ms (r=0.505; 95% CI: -0.035 to 0.817; P=0.06), but after controlling for physical activity level the relationship was stronger and statistically significant (r=0.605; 95% CI: 0.109 to 0.859; P=0.029). These results suggest that the BLD for explosive force (0-50ms) might represent a performance-limiting factor for sit-to-stand transfer in postmenopausal women and could be dependent of the physical activity level. Trial registered at Clinical Trials Gov.: NCT02434185.

Utilidad de medios de cultivo con sangre de carnero en el aislamiento de Mycobacterium tuberculosis / Usefulness of culture media with ram’s blood in the isolation of Mycobacterium tuberculosis

Introducción:Conocer la utilidad de varios medios en el aislamiento deMycobacterium tuberculosis.Material y metodos:97 cepas de M. tuberculosis se cultivaron en: Agar Columbia,agar tripticasa soja, GC agar y agar infusión corazón-cerebro.Todos tenían 10% de sangre de carnero como suplemento.Resultados:Más del 95% de las cepas crecen, no encontrando diferenciasestadísticamente significativas. La mayoría de las cepascrecen a la tercera semana de incubación.Conclusiones:El crecimiento de M. tuberculosis en medios con agar suplementadoscon sangre de carnero tras incubación prolongadadebe ser tenido en cuenta para mejorar el diagnóstico de estemicroorganismo en muestras escasas o en las que no se sospechóinicialmente la posible implicación de este patógeno. Además,el crecimiento de M. tuberculosis en medios con base deagar debe tenerse en cuenta a la hora de mantener las medidasde seguridad adecuadas en el manejo de estos cultivos

Introduction:To determine the usefulness of various media in the isolationof Mycobacterium tuberculosisMaterial and methods:Ninety seven M. tuberculosis strains were cultured in:Columbia agar, soya-tripticase agar, GC agar and heart braininfusion agar. All are suplemented with 10% ram’s blood.Results:Over 95% of the strains grew, and no statistically significantdifferences were found. Most strains grew during the thirdweek of incubation.Conclusions:The growth of M. tuberculosis in agar media suplementedwith ram’s blood after prolonged incubation should be taken intoaccount in order to improve the diagnosis of this microorganismin small samples or in those in which involvement of thispathogen was not initially suspected. In addition, the growth ofM. tuberculosis in agar base media should be borne in mindwhen maintaining the appropriate safety measures during handlingof these cultures

Influence of various criteria for elimination of duplicates when calculating the prevalence and antibiotic susceptibility of microorganisms associated with urinary infections.

The effect of applying various criteria for elimination of repeated isolates in the same patient on the prevalence and antibiotic susceptibility of microorganisms frequently associated with urinary infections were analyzed. When time criteria were applied, there was a decrease in the number of isolates of 13.4-27.5%, whereas when variations in antibiotic susceptibility were considered, between 4.3 and 20.3% of the isolates were eliminated. The absolute number of isolates varied considerably depending on which of these two criteria were used, but neither criterion was seen to modify significantly the antibiotic susceptibility of these microorganisms and this confirms the recommendations of the NCCLS for this group of pathogens.

The TolQ-TolR proteins energize TolA and share homologies with the flagellar motor proteins MotA-MotB.

The Tol-Pal system of Escherichia coli is required for the maintenance of outer membrane stability. Recently, proton motive force (pmf) has been found to be necessary for the co-precipitation of the outer membrane lipoprotein Pal with the inner membrane TolA protein, indicating that the Tol-Pal system forms a transmembrane link in which TolA is energized. In this study, we show that both TolQ and TolR proteins are essential for the TolA-Pal interaction. A point mutation within the third transmembrane (TM) segment of TolQ was found to affect the TolA-Pal interaction strongly, whereas suppressor mutations within the TM segment of TolR restored this interaction. Modifying the Asp residue within the TM region of TolR indicated that an acidic residue was important for the pmf-dependent interaction of TolA with Pal and outer membrane stabilization. Analysis of sequence alignments of TolQ and TolR homologues from numerous Gram-negative bacterial genomes, together with analyses of the different tolQ-tolR mutants, revealed that the TM domains of TolQ and TolR present structural and functional homologies not only to ExbB and ExbD of the TonB system but also with MotA and MotB of the flagellar motor. The function of these three systems, as ion potential-driven molecular motors, is discussed

The Tol-Pal proteins of the Escherichia coli cell envelope: an energized system required for outer membrane integrity?

The outer membrane of gram-negative bacteria acts as a barrier against harmful lipophilic compounds and larger molecules unable to diffuse freely through the porins. However, outer membrane proteins together with the Tol-Pal and TonB systems have been exploited for the entry of macromolecules such as bacteriocins and phage DNA through the Escherichia coli cell envelope. The TonB system is involved in the active transport of iron siderophores and vitamin B12, while no more precise physiological role of the Tol-Pal system has yet been defined than its requirement for cell envelope integrity. These two systems, containing an energized inner membrane protein interacting with outer membrane proteins, share similarities.

Proton motive force drives the interaction of the inner membrane TolA and outer membrane pal proteins in Escherichia coli.

The Tol-Pal system of the Escherichia coli envelope is formed from the inner membrane TolQ, TolR and TolA proteins, the periplasmic TolB protein and the outer membrane Pal lipoprotein. Any defect in the Tol-Pal proteins or in the major lipoprotein (Lpp) results in the loss of outer membrane integrity giving hypersensitivity to drugs and detergents, periplasmic leakage and outer membrane vesicle formation. We found that multicopy plasmid overproduction of TolA was able to complement the membrane defects of an lpp strain but not those of a pal strain. This result indicated that overproduced TolA has an envelope-stabilizing effect when Pal is present. We demonstrate that Pal and TolA formed a complex using in vivo cross-linking and immunoprecipitation experiments. These results, together with in vitro experiments with purified Pal and TolA derivatives, allowed us to show that Pal interacts with the TolA C-terminal domain. We also demonstrate using protonophore, K+ carrier valinomycin, nigericin, arsenate and fermentative conditions that the proton motive force was coupled to this interaction.

[Tuberculosis in a social health care center: epidemiologic study and prevention activities]. / La tuberculosis en un centro sociosanitario: estudio epidemiológico y actuaciones preventivas.

BACKGROUND: The high prevalence of infection and the often atipic presentation of tuberculosis in older people constitute an important risk factor for the nosocomial spread of the infection in the long-term care hospitals. PATIENTS AND METHOD: After a tuberculosis case, in a patient with positive sputum smears, in a long-term care hospital with 220 beds, we established a preventive programme that was based on: a) the determination, by the tuberculin test, of the prevalence of tuberculosis infection; b) the early detection of new cases of the disease, and c) the evaluation of the indications of the chemoprophylaxis. RESULTS: The global prevalence of the tuberculosis infection was 44%. 16% of the patients with a significant reaction to tuberculin showed lung fibrosis in the X-ray of the thorax and 27% of them were diagnosed as active tuberculosis. During the first year of the study, the rate of illness between the infected cases was 6.45%. After 2 years the conversion rate of the tuberculin test was 6.25%. CONCLUSIONS: Tuberculosis is an endemic infection in our long-term care hospital and the diagnostic delay of the active illness is an important risk factor for its dissemination. The difficulty of the interpretation of the response to the tuberculin test in old people, the evidence of the hidden illness in patients with lung fibrosis and some physic-psychological conditions of those patients, make the application of the chemoprophylaxis difficult.