A Mutant of Arabidopsis thaliana with a Reduced Response to Fusicoccin. I

Because fusicoccin (FC) has the the capacity to promote solute uptake, a selective procedure for isolating mutants of Arabidopsis thaliana with a reduced response to the toxin has been developed. The procedure is based on the incubation of A. thaliana seedlings in a solution containing the cation Paraquat (Pq) at a concentration that per se does not produce bleaching of the leaves upon illumination but does in the presence of FC because of the increased uptake of the toxic cation. Using this procedure, we identified, among the progenies of 2010 M1 ethyl methanesulfonate-mutagenized plants, two mutants that stay green after exposure to FC and Pq. Some properties and inheritance of one of the two mutants (5\u20132) are described. Morphology of mutant plants is almost indistinguishable from that of the wild type. However, 5\u20132 seeds germinate and produce viable seedlings in the presence of FC plus the aminoglycoside antibiotic hygromycin B: plants of the mutant do not wilt when exposed to FC and stomata do not open or open only partially. In the presence of FC, the mutant appears less responsive than the wild type as far as the increment in fresh weight, the enlargement of leaf disc area, or the stimulation of H+ extrusion is concerned. Inheritance of the trait is monogenic dominant or semidominant, depending on the test used

Ethanol-Induced Activation of ATP-Dependent Proton Extrusion in Elodea densa Leaves

In Elodea densa leaves, ethanol up to 0.17 M stimulates H+ extrusion activity. This effect is strictly dependent on the presence of K+ in the medium and is suppressed by the presence of the plasmalemma H+-ATPase inhibitor vanadate. Stimulation of H+ extrusion is associated with (a) a decrease in cellular ATP level, (b) a marked hyperpolarization of transmembrane electrical potential, and (c) an increase in net K+ influx. These results suggest that ethanol-induced H+ extrusion is mediated by an activation of the plasma membrane ATP-dependent, electrogenic proton pump. This stimulating effect is associated with an increase of cell sap pH and of the capacity to take up the weak acid 5,5-dimethyloxazolidine-2,4-dione, which is interpretable as due to an increase of cytosolic pH. This indicates that the stimulation of H+ extrusion by ethanol does not depend on a cytosolic acidification by products of ethanol metabolism. The similarity of the effects of ethanol and those of photosynthesis on proton pump activity in E. densa leaves suggests that a common metabolic situation is responsible for the activation of the ATP-dependent H+-extruding mechanism

Antipsychotic drug exposure and risk of pulmonary embolism: a population-based, nested case–control study

Only three observational studies investigated whether exposure to antipsychotics is associated with an increased risk of pulmonary embolism, with conflicting results. This study was therefore carried out to establish the risk of pulmonary embolism associated with antipsychotic drugs, and to ascertain the risk associated with first- and second-generation antipsychotic drugs, and with exposure to individual drugs

Neuroanatomical heterogeneity and homogeneity in individuals at clinical high risk for psychosis

Individuals at Clinical High Risk for Psychosis (CHR-P) demonstrate heterogeneity in clinical profiles and outcome features. However, the extent of neuroanatomical heterogeneity in the CHR-P state is largely undetermined. We aimed to quantify the neuroanatomical heterogeneity in structural magnetic resonance imaging measures of cortical surface area (SA), cortical thickness (CT), subcortical volume (SV), and intracranial volume (ICV) in CHR-P individuals compared with healthy controls (HC), and in relation to subsequent transition to a first episode of psychosis. The ENIGMA CHR-P consortium applied a harmonised analysis to neuroimaging data across 29 international sites, including 1579 CHR-P individuals and 1243 HC, offering the largest pooled CHR-P neuroimaging dataset to date. Regional heterogeneity was indexed with the Variability Ratio (VR) and Coefficient of Variation (CV) ratio applied at the group level. Personalised estimates of heterogeneity of SA, CT and SV brain profiles were indexed with the novel Person-Based Similarity Index (PBSI), with two complementary applications. First, to assess the extent of within-diagnosis similarity or divergence of neuroanatomical profiles between individuals. Second, using a normative modelling approach, to assess the ‘normativeness’ of neuroanatomical profiles in individuals at CHR-P. CHR-P individuals demonstrated no greater regional heterogeneity after applying FDR corrections. However, PBSI scores indicated significantly greater neuroanatomical divergence in global SA, CT and SV profiles in CHR-P individuals compared with HC. Normative PBSI analysis identified 11 CHR-P individuals (0.70%) with marked deviation (>1.5 SD) in SA, 118 (7.47%) in CT and 161 (10.20%) in SV. Psychosis transition was not significantly associated with any measure of heterogeneity. Overall, our examination of neuroanatomical heterogeneity within the CHR-P state indicated greater divergence in neuroanatomical profiles at an individual level, irrespective of psychosis conversion. Further large-scale investigations are required of those who demonstrate marked deviation.publishedVersio