195 research outputs found
Antifungal Susceptibility Profiles of 1698 Yeast Reference Strains Revealing Potential Emerging Human Pathogens
New molecular identification techniques and the increased number of patients with various immune defects or underlying conditions lead to the emergence and/or the description of novel species of human and animal fungal opportunistic pathogens. Antifungal susceptibility provides important information for ecological, epidemiological and therapeutic issues. The aim of this study was to assess the potential risk of the various species based on their antifungal drug resistance, keeping in mind the methodological limitations. Antifungal susceptibility profiles to the five classes of antifungal drugs (polyens, azoles, echinocandins, allylamines and antimetabolites) were determined for 1698 yeast reference strains belonging to 992 species (634 Ascomycetes and 358 Basidiomycetes). Interestingly, geometric mean minimum inhibitory concentrations (MICs) of all antifungal drugs tested were significantly higher for Basidiomycetes compared to Ascomycetes (p<0.001). Twenty four strains belonging to 23 species of which 19 were Basidiomycetes seem to be intrinsically “resistant” to all drugs. Comparison of the antifungal susceptibility profiles of the 4240 clinical isolates and the 315 reference strains belonging to 53 shared species showed similar results. Even in the absence of demonstrated in vitro/in vivo correlation, knowing the in vitro susceptibility to systemic antifungal agents and the putative intrinsic resistance of yeast species present in the environment is important because they could become opportunistic pathogens
Supporting Earth-Observation Calibration and Validation: A new generation of tools for crowdsourcing and citizen science
Citizens are providing vast amounts of georeferenced data in the form of in situ data collections as well as interpretations and digitization of Earth-observation (EO) data sets.
These new data streams have considerable potential for supporting the calibration and validation of current and future products derived from EO. We provide a general introduction to this growing area of interest and review existing crowdsourcing and citizen science (CS) initiatives of relevance to EO. We then draw upon our own experiences to provide case studies that highlight different types of data collection and citizen engagement and discuss the various barriers to adoption.
Finally, we highlight opportunities for how citizens can become part of an integrated EO monitoring system in the framework of the European Union (EU) space program, including Copernicus and other monitoring initiatives
Features of the primary wall CESA complex in wild type and cellulose-deficient mutants of Arabidopsis thaliana
Evidence from genetics, co-precipitation and bimolecular fluorescence complementation suggest that three CESAs implicated in making primary wall cellulose in Arabidopsis thaliana form a complex. This study shows the complex has a Mr of approximately 840 kDa in detergent extracts and that it has undergone distinctive changes when extracts are prepared from some cellulose-deficient mutants. The mobility of CESAs 1, 3, and 6 in a Triton-soluble microsomal fraction subject to blue native polyacrylamide gel electrophoresis was consistent with a Mr of about 840 kDa. An antibody specific to any one CESA pulled down all three CESAs consistent with their occupying the same 840 kDa complex. In rsw1, a CESA1 missense mutant, extracts of seedlings grown at the permissive temperature have an apparently normal CESA complex that was missing from extracts of seedlings grown at the restrictive temperature where CESAs precipitated independently. In prc1-19, with no CESA6, CESAs 1 and 3 were part of a 420 kDa complex in extracts of light-grown seedlings that was absent from extracts of dark-grown seedlings where the CESAs precipitated independently. Two CESA3 missense mutants retained apparently normal CESA complexes as did four cellulose-deficient mutants defective in proteins other than CESAs. The 840 kDa complex could contain six CESA subunits and, since loss of plasma membrane rosettes accompanies its loss in rsw1, the complex could form one of the six particles which electron microscopy reveals in rosettes
Characterization of the paracrine effects of human skeletal myoblasts transplanted in infarcted myocardium
The discrepancy between the functional improvements yielded experimentally by skeletal myoblasts (SM) transplanted in
infarcted myocardium and the paucity of their long-term engraftment has raised the hypothesis of cell-mediated paracrine mechanisms.
Methods and results: We analyzed gene expression and growth factors released by undifferentiated human SM (CD56+), myotubes (SM
cultured until confluence) and fibroblasts-like cells (CD56−). Gene expression revealed up-regulation of pro-angiogenic (PGF), antiapoptotics
(BAG-1, BCL-2), heart development (TNNT2, TNNC1) and extracellular matrix remodelling (MMP-2, MMP-7) genes in SM. In
line with the gene expression profile, the analysis of culture supernatants of SM by ELISA identified the release of growth factors involved in
angiogenesis (VEGF, PIGF, angiogenin, angiopoietin, HGF and PDGF-BB) as well as proteases involved in matrix remodelling (MMP2,
MMP9 and MMP10) and their inhibitors (TIMPs). Culture of smooth muscle cells (SMC), cardiomyocytes (HL-1) and human umbilical vein
endothelial cells (HUVECs) with SM-released conditioned media demonstrated an increased proliferation of HUVEC, SMC and
cardiomyocytes (pb0.05) and a decrease in apoptosis of cardiomyocytes (pb0.05). Analysis of nude rats transplanted with human SM
demonstrated expression of human-specific MMP-2, TNNI3, CNN3, PGF, TNNT2, PAX7, TGF-β, and IGF-1 1 month after transplant.
Conclusions: Our data support the paracrine hypothesis whereby myoblast-secreted factors may contribute to the beneficial effects of
myogenic cell transplantation in infarcted myocardium.
© 2008 European Society of Cardiology. Published by Elsevie
Myosin5a tail associates directly with Rab3A-containing compartments in neurons
Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of American Society for Biochemistry and Molecular Biology. The definitive version was published in Journal of Biological Chemistry, 286 (2011): 14352-14361, doi:10.1074/jbc.M110.187286.Myosin-Va (Myo5a) is a motor protein
associated with synaptic vesicles (SVs) but the
mechanism by which it interacts has not yet
been identified. A potential class of binding
partners are Rab GTPases and Rab3A is known
to associate with SVs and is involved in SV
trafficking. We performed experiments to
determine whether Rab3A interacts with
Myo5a and whether it is required for transport
of neuronal vesicles. In vitro motility assays
performed with axoplasm from the squid giant
axon showed a requirement for a Rab GTPase
in Myo5a-dependent vesicle transport.
Furthermore, mouse recombinant Myo5a tail
revealed that it associated with Rab3A in rat
brain synaptosomal preparations in vitro and
the association was confirmed by
immunofluorescence imaging of primary
neurons isolated from the frontal cortex of
mouse brains. Synaptosomal Rab3A was
retained on recombinant GST-tagged Myo5a
tail affinity columns in a GTP-dependent
manner. Finally, the direct interaction of
Myo5a and Rab3A was determined by
sedimentation v e l o c i t y analytical
ultracentrifugation using recombinant mouse
Myo5a tail and human Rab3A. When both
proteins were incubated in the presence of 1
mM GTPγS, Myo5a tail and Rab3A formed a
complex and a direct interaction was observed.
Further analysis revealed that GTP-bound
Rab3A interacts with both the monomeric and
dimeric species of the Myo5a tail. However, the
interaction between Myo5a tail and nucleotidefree
Rab3A did not occur. Thus, our results
show that Myo5a and Rab3A are direct binding
partners and interact on SVs and that the
Myo5a/Rab3A complex is involved in transport
of neuronal vesicles
Identification of Phosphatin, a Drug Alleviating Phosphate Starvation Responses in Arabidopsis
The Ternary Rab27a–Myrip–Myosin VIIa Complex Regulates Melanosome Motility in the Retinal Pigment Epithelium
The retinal pigment epithelium (RPE) contains melanosomes similar to those found in the skin melanocytes, which undergo dramatic light-dependent movements in fish and amphibians. In mammals, those movements are more subtle and appear to be regulated by the Rab27a GTPase and the unconventional myosin, Myosin VIIa (MyoVIIa). Here we address the hypothesis that a recently identified Rab27a- and MyoVIIa-interacting protein, Myrip, promotes the formation of a functional tripartite complex. In heterologous cultured cells, all three proteins co-immunoprecipitated following overexpression. Rab27a and Myrip localize to the peripheral membrane of RPE melanosomes as observed by immunofluorescence and immunoelectron microscopy. Melanosome dynamics were studied using live-cell imaging of mouse RPE primary cultures. Wild-type RPE melanosomes exhibited either stationary or slow movement interrupted by bursts of fast movement, with a peripheral directionality trend. Nocodazole treatment led to melanosome paralysis, suggesting that movement requires microtubule motors. Significant and similar alterations in melanosome dynamics were observed when any one of the three components of the complex was missing, as studied in ashen- (Rab27a defective) and shaker-1 (MyoVIIa mutant)-derived RPE cells, and in wild-type RPE cells transduced with adenovirus carrying specific sequences to knockdown Myrip expression. We observed a significant increase in the number of motile melanosomes, exhibiting more frequent and prolonged bursts of fast movement, and inversion of directionality. Similar alterations were observed upon cytochalasin D treatment, suggesting that the Rab27a–Myrip–MyoVIIa complex regulates tethering of melanosomes onto actin filaments, a process that ensures melanosome movement towards the cell periphery
Roles of Myosin Va and Rab3D in Membrane Remodeling of Immature Secretory Granules
Neuroendocrine secretory granules (SGs) are formed at the trans-Golgi network (TGN) as immature intermediates. In PC12 cells, these immature SGs (ISGs) are transported within seconds to the cell cortex, where they move along actin filaments and complete maturation. This maturation process comprises acidification-dependent processing of cargo proteins, condensation of the SG matrix, and removal of membrane and proteins not destined to mature SGs (MSGs) into ISG-derived vesicles (IDVs). We investigated the roles of myosin Va and Rab3 isoforms in the maturation of ISGs in neuroendocrine PC12 cells. The expression of dominant-negative mutants of myosin Va or Rab3D blocked the removal of the endoprotease furin from ISGs. Furthermore, expression of mutant Rab3D, but not of mutant myosin Va, impaired cargo processing of SGs. In conclusion, our data suggest an implication of myosin Va and Rab3D in the maturation of SGs where they participate in overlapping but not identical tasks
Heart Rate and Risk of Cancer Death in Healthy Men
BACKGROUND: Data from several previous studies examining heart-rate and cardiovascular risk have hinted at a possible relationship between heart-rate and non-cardiac mortality. We thus systematically examined the predictive value of heart-rate variables on the subsequent risk of death from cancer. METHODS: In the Paris Prospective Study I, 6101 asymptomatic French working men aged 42 to 53 years, free of clinically detectable cardiovascular disease and cancer, underwent a standardized graded exercise test between 1967 and 1972. Resting heart-rate, heart-rate increase during exercise, and decrease during recovery were measured. Change in resting heart-rate over 5 years was also available in 5139 men. Mortality including 758 cancer deaths was assessed over the 25 years of follow-up. FINDINGS: There were strong, graded and significant relationships between all heart-rate parameters and subsequent cancer deaths. After adjustment for age and tobacco consumption and, compared with the lowest quartile, those with the highest quartile for resting heart-rate had a relative risk of 2.4 for cancer deaths (95% confidence interval: 1.9-2.9, p<0.0001) This was similar after adjustment for traditional cardiovascular risk factors and was observed for the commonest malignancies (respiratory and gastrointestinal). Similarly, significant relationships with cancer death were observed between poor heart rate increase during exercise, poor decrease during recovery and greater heart-rate increase over time (p<0.0001 for all). INTERPRETATION: Resting and exercise heart rate had consistent, graded and highly significant associations with subsequent cancer mortality in men
A Novel fry1 Allele Reveals the Existence of a Mutant Phenotype Unrelated to 5′->3′ Exoribonuclease (XRN) Activities in Arabidopsis thaliana Roots
International audienceBackgroundMutations in the FRY1/SAL1 Arabidopsis locus are highly pleiotropic, affecting drought tolerance, leaf shape and root growth. FRY1 encodes a nucleotide phosphatase that in vitro has inositol polyphosphate 1-phosphatase and 3′,(2′),5′-bisphosphate nucleotide phosphatase activities. It is not clear which activity mediates each of the diverse biological functions of FRY1 in planta.Principal FindingsA fry1 mutant was identified in a genetic screen for Arabidopsis mutants deregulated in the expression of Pi High affinity Transporter 1;4 (PHT1;4). Histological analysis revealed that, in roots, FRY1 expression was restricted to the stele and meristems. The fry1 mutant displayed an altered root architecture phenotype and an increased drought tolerance. All of the phenotypes analyzed were complemented with the AHL gene encoding a protein that converts 3′-polyadenosine 5′-phosphate (PAP) into AMP and Pi. PAP is known to inhibit exoribonucleases (XRN) in vitro. Accordingly, an xrn triple mutant with mutations in all three XRNs shared the fry1 drought tolerance and root architecture phenotypes. Interestingly these two traits were also complemented by grafting, revealing that drought tolerance was primarily conferred by the rosette and that the root architecture can be complemented by long-distance regulation derived from leaves. By contrast, PHT1 expression was not altered in xrn mutants or in grafting experiments. Thus, PHT1 up-regulation probably resulted from a local depletion of Pi in the fry1 stele. This hypothesis is supported by the identification of other genes modulated by Pi deficiency in the stele, which are found induced in a fry1 background.Conclusions/SignificanceOur results indicate that the 3′,(2′),5′-bisphosphate nucleotide phosphatase activity of FRY1 is involved in long-distance as well as local regulatory activities in roots. The local up-regulation of PHT1 genes transcription in roots likely results from local depletion of Pi and is independent of the XRNs.
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