Melvin Calvin (1911-1997): un Premio Nobel de Química que revolucionó la fisiología vegetal

Artículo dedicado a la memoria de Melvin Calvin, premio Nobel de química en 1961, con ocasión del primer centenario de su nacimiento (2011

Necrotic and cytolytic activity on grapevine leaves produced by Nep1-like proteins of Diplodia seriata

This article is part of the Research Topic Recent Advances on Grapevine-Microbe Interactions: From Signal Perception to Resistance Response[EN] Many phytopathogenic fungi produce necrosis and ethylene inducing peptide 1 (Nep1- like proteins or NLP) that trigger leaf necrosis and the activation of defense mechanisms. These proteins have been widely studied in plant pathogens as Moniliophthora perniciosa or Botrytis cinerea between others, but little is known about their biological roles in grapevine trunk pathogens. Advances in the sequencing of genomes of several fungi involved in grapevine trunk diseases have revealed that these proteins are present in several copies in their genomes. The aim of this project was to analyze the presence of genes encoding NLP proteins in the Diplodia seriata genome and to characterize their putative role as virulence factors associated to grapevine trunk diseases. In this study, we characterized four NLPs from Diplodia seriata. All proteins showed highly similar amino acid sequences and contained the characteristic peptide motifs of NLPs. DserNEPs slightly reduced the viability of Vitis vinifera L. cell cultures. The cytolytic activity from DserNEP1 was stronger than that from DserNEP2, even at low concentrations. Purified DserNEPs also produced necrosis in leaves when they were inoculated into micropropagules of V. vinifera L. This is the first record of Nep1-like proteins from a fungus associated with grapevine trunk diseases and also from a member of the Botryosphaeriaceae familySIThis work was supported by Bodegas Vega Sicilia S.A. (Valbuena de Duero, Valladolid, Spain

Development of a predictor for human brain tumors based on gene expression values obtained from two types of microarray technologies

Development of molecular diagnostics that can reliably differentiate amongst different subtypes of brain tumors is an important unmet clinical need in postgenomics medicine and clinical oncology. A simple linear formula derived from gene expression values of four genes (GFAP, PTPRZ1, GPM6B, and PRELP) measured from cDNA microarrays (n=35) have distinguished glioblastoma and meningioma cases in a previous study. We herein extend this work further and report that the above predictor formula showed its robustness when applied to Affymetrix microarray data acquired prospectively in our laboratory (n=80) as well as publicly available data (n=98). Importantly, GFAP and GPM6B were both retained as being significant in the predictive model upon using the Affymetrix data obtained in our laboratory, whereas the other two predictor genes were SFRP2 and SLC6A2. These results collectively indicate the importance of the expression values of GFAP and GPM6B genes sampled from the two types of microarray technologies tested. The high prediction accuracy obtained in these instances demonstrates the robustness of the predictors across microarray platforms used. This result would require further validation with a larger population of meningioma and glioblastoma cases. At any rate, this study paves the way for further application of gene signatures to more stringent biopsy discrimination challenges. © 2010, Mary Ann Liebert, Inc.This work was funded by the EU-funded grants eTUMOUR (FP6-2002-LIFESCIHEALTH503094),HealthAgents (IST-2004-27214) and the Spanish grant MEDIVO2 (SAF 2005-03650). CIBER-BNN is an initiative of ‘‘Instituto de Salud Carlos III’’ (ISCIII, Spain).Peer Reviewe

Manganese transporter protein MntH is required for virulence of Xylophilus ampelinus, the causal agent of bacterial necrosis in grapevine

This journal is published by Hindawi as part of a publishing collaboration with the Australian Society of Viticulture and Oenology. It is a fully open access journal produced under the Hindawi and Wiley brands[EN] Background and Aims: The aim of this study is to identify proteins involved in the pathogenicity/virulence of Xylophilus ampelinus. Characterisation of these proteins could provide new insights into putative targets for controlling bacterial necrosis in grapevines. Methods and Results: Transposon insertion mutagenesis was used to isolate X. ampelinus mutants exhibiting an altered virulence. Characterisation of one of the avirulent mutants revealed the insertion of a transposon into the mntH gene encoding the major manganese transporter. Virulence tests on grapevine leaves clearly showed that the virulence of these mutants was significantly reduced. Phenotypic analysis of an mntH mutant indicated that the MntH protein is a Mn++ transporter but that MntH does not play a significant role in the transport of Fe++ or Cu++. The MntH mutants exhibited an increased sensitivity to hydrogen peroxide, although catalase and superoxide dismutase activities were not significantly affected. Conclusion: The MntH protein plays a significant role in the virulence of X. ampelinus. Significance of the Study: This is the first report showing that transposon mutagenesis is an effective strategy for the isolation of X. ampelinus mutants. It is also the first report characterising a gene encoding a protein involved in virulence in this grapevine pathogenSIThis work was financed by a Research Contract sponsored by Bodegas Vega Sicilia S.A. (Valbuena de Duero, Valladolid, Spain

Non-invasive grading of astrocytic tumours from the relative contents of myo-inositol and glycine measured by in vivo MRS

Altres ajuts: INTERPRET (EU-IST1999-10310). This work was also partially funded by the Centro de Investigación Biomédica en Red - Bioingeniería, Biomateriales y Nanomedicina, which is an initiative of the Instituto de Salud Carlos III (Spain) co-funded by EU FEDER funds.MRI and MRS are established methodologies for evaluating intracranial lesions. One MR spectral feature suggested for in vivo grading of astrocytic tumours is the apparent myo-Inositol (mI) intensity (ca 3.55ppm) at short echo times, although glycine (gly) may also contribute in vivo to this resonance. The purpose of this study was to quantitatively evaluate the mI + gly contribution to the recorded spectral pattern in vivo and correlate it with in vitro data obtained from perchloric acid extraction of tumour biopsies. Patient spectra (n = 95) at 1.5T at short (20-31 ms) and long (135-136 ms) echo times were obtained from the INTERPRET MRS database (http://gabrmn.uab.es/interpretvalidateddb/). Phantom spectra were acquired with a comparable protocol. Spectra were automatically processed and the ratios of the (mI + gly) to Cr peak heights ((mI + gly)/Cr) calculated. Perchloric acid extracts of brain tumour biopsies were analysed by high-resolution NMR at 9.4T. The ratio (mI + gly)/Cr decreased significantly with astrocytic grade in vivo between low-grade astrocytoma (A2) and glioblastoma multiforme (GBM). In vitro results displayed a somewhat different tendency, with anaplastic astrocytomas having significantly higher (mI + gly)/Cr than A2 and GBM. The discrepancy between in vivo and in vitro data suggests that the NMR visibility of glycine in glial brain tumours is restricted in vivo

Activation of p53 by nutlin-3a induces apoptosis and cellular senescence in human glioblastoma multiforme

Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumor in adults. Despite concerted efforts to improve current therapies and develop novel clinical approaches, patient survival remains poor. As such, increasing attention has focused on developing new therapeutic strategies that specifically target the apoptotic pathway in order to improve treatment responses. Recently, nutlins, small-molecule antagonists of MDM2, have been developed to inhibit p53-MDM2 interaction and activate p53 signaling in cancer cells. Glioma cell lines and primary cultured glioblastoma cells were treated with nutlin-3a. Nutlin-3a induced p53-dependent G1- and G2-M cell cycle arrest and apoptosis in glioma cell lines with normal TP53 status. In addition, nutlin-arrested glioma cells show morphological features of senescence and persistent induction of p21 protein. Furthermore, senescence induced by nutlin-3a might be depending on mTOR pathway activity. In wild-type TP53 primary cultured cells, exposure to nutlin-3a resulted in variable degrees of apoptosis as well as cellular features of senescence. Nutlin-3a-induced apoptosis and senescence were firmly dependent on the presence of functional p53, as revealed by the fact that glioblastoma cells with knockdown p53 with specific siRNA, or cells with mutated or functionally impaired p53 pathway, were completely insensitive to the drug. Finally, we also found that nutlin-3a increased response of glioma cells to radiation therapy. The results provide a basis for the rational use of MDM2 antagonists as a novel treatment option for glioblastoma patients

Reproducibility of Anterior Scalene Stiffness Measurement with Shear Wave Elastography: An Inter-Examiner Reliability Study.

Purpose: Although previous studies highlighted the clinical relevance of the anterior scalene muscle (AS) in patients with neck pain or nerve compressive syndromes, evidence reporting the diagnostic accuracy of shear wave elastography (SWE) for assessing the AS stiffness properties is lacking. This study aimed to analyze the SWE inter-examiner reliability for calculating the Young’s modulus and shear wave speed of the AS muscle in asymptomatic subjects. Material and Methods: Using a linear transducer, ultrasound images of the antero-lateral neck region at C7 level were acquired in 35 healthy volunteers by one experienced examiner and one novel examiner. After codifying the images to blind the participant identity, trial and side, Young’s modulus and shear wave speed were obtained by an independent experienced rater in randomized order. Intra-class correlation coefficients (ICC), standard error of measurement (SEM), minimal detectable changes (MDC) and coefficient of variation (CV%) were calculated. Results: The AS metrics assessed showed no side-to-side differences (p>0.05). Sex differences were found for muscle size (p=0.002), but muscle brightness and stiffness were similar (p>0.05). Inter-examiner reliability was good for determining the AS muscle stiffness (ICC = 0.881 for Young’s modulus and 0.850 for shear wave speed). Conclusion: The obtained results suggest that assessing the AS stiffness properties in asymptomatic subjects is a reliable procedure. Further studies should verify the SWE capacity for discriminating healthy and clinical populations and identify potential factors contributing to the variance of measurement errors.pre-print180 K

Clinical infections by herpesviruses in patients treated with valproic acid: A nested case-control study in the Spanish Primary Care Database, BIFAP

The objective of this study is to evaluate the risk of clinical infections by herpesviruses in patients exposed to valproic acid (VPA).We performed a case-control study nested in a primary cohort selected from the Spanish primary care population-based research database BIFAP (Base de datos para la Investigación Farmacoepidemiológica en Atención Primaria) over the period 2001–2015. The events of interest were those diseases caused by any herpesviruses known to infect humans. For each case, up to 10 controls per case matched by age, gender, and calendar date were randomly selected. A conditional logistic regression was used to compute adjusted odds ratios (OR) and their 95% confidence intervals (95% CI). Current use of VPA was associated with a trend towards a reduced risk of clinical infections by herpesviruses as compared with non-users (OR 0.84; CI 95% 0.7–1.0; p = 0.057). Among current users, a trend to a decreased risk with treatment durations longer than 90 days was also observed. The results show a trend to a reduced risk of clinical infection by herpesviruses in patients exposed to VPA. These results are consistent with those in vitro studies showing that, in cultured cells, VPA can inhibit the production of the infectious progeny of herpesviruses. This study also shows the efficient use of electronic healthcare records for clinical exploratory research studie

Development of robust discriminant equations for assessing subtypes of glioblastoma biopsies

In the preceding decade, various studies on glioblastoma (Gb) demonstrated that signatures obtained from gene expression microarrays correlate better with survival than with histopathological classification. However, there is not a universal consensus formula to predict patient survival. We developed a gene signature using the expression profile of 47 Gbs through an unsupervised procedure and two groups were obtained. Subsequent to a training procedure through leave-one-out cross-validation, we fitted a discriminant (linear discriminant analysis (LDA)) equation using the four most discriminant probesets. This was repeated for two other published signatures and the performance of LDA equations was evaluated on an independent test set, which contained status of IDH1 mutation, EGFR amplification, MGMT methylation and gene VEGF expression, among other clinical and molecular information. The unsupervised local signature was composed of 69 probesets and clearly defined two Gb groups, which would agree with primary and secondary Gbs. This hypothesis was confirmed by predicting cases from the independent data set using the equations developed by us. The high survival group predicted by equations based on our local and one of the published signatures contained a significantly higher percentage of cases displaying IDH1 mutation and non-amplification of EGFR. In contrast, only the equation based on the published signature showed in the poor survival group a significant high percentage of cases displaying a hypothesised methylation of MGMT gene promoter and overexpression of gene VEGF. We have produced a robust equation to confidently discriminate Gb subtypes based in the normalised expression level of only four genes