Targeted gene expression study of Salmonella enterica during biofilm formation on rocket leaves

In the present study, the ability of Salmonella Typhimurium to form biofilm community on rocket leaves and rocket extract at 10 C and 20 C was investigated. This goal was achieved with the study of expression of genes associated with biofilm formation and other functional roles. The obtained results showed that Salmonella growth was inhibited when cultured in rocket extract (liquid and solid state) and when grew directly to rocket leaves. The observed inhibition might be attributed to nutrient starvation to the specific growth media because of plant leaves's variability, cell physiology and antimicrobial compounds of rocket. In addition, gene expression study using Real-Time PCR showed that biofilm was formatted on solid media, while the entrance and adhesion of the microorganism within the plant held more strongly through the stomata of the plant leaves. Furthermore, genes associated with managing stress situations were overexpressed at 20 C. From these results, it is indicated that further studies are needed to better determine the survival and/or growth of the pathogen as “real” biofilm cells on plants. In addition, the study on development and gene expression of biofilm cells is necessary in order to eliminate the specific pathogen and reduce the food-borne diseases it causes

Low temperature methane conversion with perovskite-supported: exo / endo-particles

Lowering the temperature at which CH(4)is converted to useful products has been long-sought in energy conversion applications. Selective conversion to syngas is additionally desirable. Generally, most of the current CH(4)activation processes operate at temperatures between 600 and 900 degrees C when non-noble metal systems are used. These temperatures can be even higher for redox processes where a gas phase-solid reaction must occur. Here we employ the endogenous-exsolution concept to create a perovskite oxide with surface and embedded metal nanoparticles able to activate methane at temperatures as low as 450 degrees C in a cyclic redox process. We achieve this by using a non-noble, Co-Ni-based system with tailored nano- and micro-structure. The materials designed and prepared in this study demonstrate long-term stability and resistance to deactivation mechanisms while still being selective when applied for chemical looping partial oxidation of methane

Monitoring the growth of Salmonella enterica serovar typhimurium in silico and in situ with a view in gene expression

In the present study, the ability of S. Typhimurium to develop a biofilm community on rocket tissue was investigated at 20°C. The differences on expression of genes associated with several functional roles during growth of S. Typhimurium on rocket extract and rocket tissue regarding a laboratory growth medium (Luria – Bertani broth, LB) was also monitored. The findings of the present study could show that Salmonella reacts as exposed to different types of stress when inoculated to a heat sterile plant extract and plant tissue. However, further studies are needed to better determine the survival and / or growth of these as “real” biofilm cells on plant tissues

In the fetal thymus, Gli3 in thymic epithelial cells promotes thymocyte positive selection and differentiation by repression of Shh

Gli3 is a Hedgehog (Hh) responsive transcription factor that can function as a transcriptional repressor or activator. We show that Gli3 activity in thymic epithelial cells (TEC) promotes positive selection and differentiation from CD4+CD8+ to CD4+CD8- single positive (SP4) cell in the fetal thymus and that Gli3 represses Shh Constitutive deletion of Gli3, and conditional deletion of Gli3 from TEC, reduced differentiation to SP4, whereas conditional deletion of Gli3 from thymocytes did not. Conditional deletion of Shh from TEC increased differentiation to SP4, and expression of Shh was upregulated in the Gli3-deficient thymus. Use of a transgenic Hh-reporter showed that the Hh pathway was active in thymocytes, and increased in the Gli3-deficient fetal thymus. Neutralisation of endogenous Hh proteins in the Gli3-/- thymus restored SP4 differentiation, indicating that Gli3 in TEC promotes SP4 differentiation by repression of Shh Transcriptome analysis showed that Hh-mediated transcription was increased but TCR-mediated transcription decreased in Gli3-/- thymocytes compared to WT

NKX2-5 regulates vessel remodelling in scleroderma-associated pulmonary arterial hypertension.

NKX2-5 is a member of the homeobox-containing transcription factors critical in regulating tissue differentiation in development. Here, we report a role for NKX2-5 in vascular smooth muscle cell phenotypic modulation in vitro and in vascular remodelling in vivo. NKX2-5 is up-regulated in scleroderma (SSc) patients with pulmonary arterial hypertension. Suppression of NKX2-5 expression in smooth muscle cells, halted vascular smooth muscle proliferation and migration, enhanced contractility and blocked the expression of the extracellular matrix genes. Conversely, overexpression of NKX2-5 suppressed the expression of contractile genes (ACTA2, TAGLN, CNN1) and enhanced the expression of matrix genes (COL1) in vascular smooth muscle cells. In vivo, conditional deletion of NKX2-5 attenuated blood vessel remodelling and halted the progression to hypertension in the mouse chronic hypoxia mouse model. This study revealed that signals related to injury such as serum and low confluence, which induce NKX2-5 expression in cultured cells, is potentiated by TGFβ and further enhanced by hypoxia. The effect of TGFβ was sensitive to ERK5 and PI3K inhibition. Our data suggest a pivotal role for NKX2-5 in the phenotypic modulation of smooth muscle cells during pathological vascular remodelling and provide proof of concept for therapeutic targeting of NKX2-5 in vasculopathies

MAF functions as a pioneer transcription factor that initiates and sustains myelomagenesis

Deregulated expression of lineage-affiliated transcription factors (TFs) is a major mechanism of oncogenesis. However, how the deregulation of nonlineage affiliated TF affects chromatin to initiate oncogenic transcriptional programs is not well-known. To address this, we studied the chromatin effects imposed by oncogenic MAF as the cancer-initiating driver in the plasma cell cancer multiple myeloma. We found that the ectopically expressed MAF endows myeloma plasma cells with migratory and proliferative transcriptional potential. This potential is regulated by the activation of enhancers and superenhancers, previously inactive in healthy B cells and plasma cells, and the cooperation of MAF with the plasma cell-defining TF IRF4. Forced ectopic MAF expression confirms the de novo ability of oncogenic MAF to convert transcriptionally inert chromatin to active chromatin with the features of superenhancers, leading to the activation of the MAF-specific oncogenic transcriptome and the acquisition of cancer-related cellular phenotypes such as CCR1-dependent cell migration. These findings establish oncogenic MAF as a pioneer transcription factor that can initiate as well as sustain oncogenic transcriptomes and cancer phenotypes. However, despite its pioneer function, myeloma cells remain MAF-dependent, thus validating oncogenic MAF as a therapeutic target that would be able to circumvent the challenges of subsequent genetic diversification driving disease relapse and drug resistance

Foxa1 and Foxa2 in thymic epithelial cells (TEC) regulate medullary TEC and regulatory T-cell maturation

The Foxa1 and Foxa2 transcription factors are essential for mouse development. Here we show that they are expressed in thymic epithelial cells (TEC) where they regulate TEC development and function, with important consequences for T-cell development. TEC are essential for T-cell differentiation, lineage decisions and repertoire selection. Conditional deletion of Foxa1 and Foxa2 from murine TEC led to a smaller thymus with a greater proportion of TEC and a greater ratio of medullary to cortical TEC. Cell-surface MHCI expression was increased on cortical TEC in the conditional Foxa1Foxa2 knockout thymus, and MHCII expression was reduced on both cortical and medullary TEC populations. These changes in TEC differentiation and MHC expression led to a significant reduction in thymocyte numbers, reduced positive selection of CD4+CD8+ cells to the CD4 lineage, and increased CD8 cell differentiation. Conditional deletion of Foxa1 and Foxa2 from TEC also caused an increase in the medullary TEC population, and increased expression of Aire, but lower cell surface MHCII expression on Aire-expressing mTEC, and increased production of regulatory T-cells. Thus, Foxa1 and Foxa2 in TEC promote positive selection of CD4SP T-cells and modulate regulatory T-cell production and activity, of importance to autoimmunity

The importance of the weak: Interaction modifiers in artificial spin ices

The modification of geometry and interactions in two-dimensional magnetic nanosystems has enabled a range of studies addressing the magnetic order, collective low-energy dynamics, and emergent magnetic properties, in e.g. artificial spin ice structures. The common denominator of all these investigations is the use of Ising-like mesospins as building blocks, in the form of elongated magnetic islands. Here we introduce a new approach: single interaction modifiers, using slave-mesospins in the form of discs, within which the mesospin is free to rotate in the disc plane. We show that by placing these on the vertices of square artificial spin ice arrays and varying their diameter, it is possible to tailor the strength and the ratio of the interaction energies. We demonstrate the existence of degenerate ice-rule obeying states in square artificial spin ice structures, enabling the exploration of thermal dynamics in a spin liquid manifold. Furthermore, we even observe the emergence of flux lattices on larger length-scales, when the energy landscape of the vertices is reversed. The work highlights the potential of a design strategy for two-dimensional magnetic nano-architectures, through which mixed dimensionality of mesospins can be used to promote thermally emergent mesoscale magnetic states.Comment: 17 pages, including methods, 4 figures. Supplementary information contains 16 pages and 15 figure

Detection of Citrobacter koseri carrying beta-lactamase KPC-2 in a hospitalised patient, Greece, July 2011

Microbial Biotechnolog