Rapid determination of protein solubility and stability conditions for NMR studies using incomplete factorial design

International audienceSample preparation constitutes a crucial and limiting step in structural studies of proteins by NMR. The determination of the solubility and stability (SAS) conditions of biomolecules at millimolar concentrations stays today empirical and hence time- and material-consuming. Only few studies have been recently done in this field and they have highlighted the interest of using crystallogenesis tools to optimise sample conditions. In this study, we have adapted a method based on incomplete factorial design and making use of crystallisation plates to quantify the influence of physico-chemical parameters such as buffer pH and salts on protein SAS. A description of the experimental set up and an evaluation of the method are given by case studies on two functional domains from the bacterial regulatory protein LicT as well as two other proteins. Using this method, we could rapidly determine optimised conditions for extracting soluble proteins from bacterial cells and for preparing purified protein samples sufficiently concentrated and stable for NMR characterisation. The drastic reduction in the time and number of experiments required for searching protein SAS conditions makes this method particularly well-adapted for a systematic investigation on a large range of physico-chemical parameters

Characteristics and effects of organic matter on Belgian loamy soils : a reference system

peer reviewe

Oral communication: Brassica napus L. plantlets affected during in vitro growth by the presence of epoxiconazole.

SolIndi

Phenotyping of Brassica napus L. plantlets affected during in vitro growth by the presence of epoxiconazole

peer reviewedEpoxiconazole like others triazole fungicides are known to be persistent in the soil. Several studies using foliar application experiments demonstrated the effect of its triazole metabolite as plant growth regulator through the anti-gibberellin activity. And notably, the reduction of Brassica napus L. growth can be attributed to the inhibition of gibberellin biosynthesis at the stage of conversion of ent-kaurene to ent-kaurenoic acid. We describe here an in vitro experiment studying the relationship between epoxiconazole in culture medium (0 mg L⁻¹, 0.120 mg L⁻¹ and 0.200 mg L⁻¹) and the phenotyping (root and shoot growth) of three varieties of winter rapeseeds (Brassica napus L. var. Catalina, var. ES Astrid and var. Toccata). Plantlets fungicide content was quantified using the QuEChERS extraction method following by an automated UHPLC-MS/MS analysis. Results showed that the shoots and roots growth of Brassica napus L. plantlets was significantly inhibited by epoxiconazole at 0.120 mg L⁻¹ independently of the variety. The concentration of 0.200 mg L⁻¹ leaded to necrosis and anthocyanosis symptoms and can be considered as lethal for in vitro growing explants. The huge epoxiconazole absorption by rapeseed plantlets clearly showed a dose-dependent relationship and was closely similar for the three varieties

Solindic: Etude de l'activité biologique du système "Sol-Plante" en vue de préserver les fonctionnalités des sols agricoles

Etude de l'activité biologique du système "Sol-Plante" en vue de préserver les fonctionnalités des sols agricoles (SOLINDIC

Preeclampsia-like symptoms induced in mice by feto-placental expression of STOX1 are reversed by aspirin treatment

Preeclampsia (PE) is a common human-specific pregnancy disorder defined by hypertension and proteinuria during gestation and responsible for maternal and fetal morbimortality. STOX1, encoding a transcription factor, was the first gene associated with PE as identified by positional cloning approaches. Its overexpression in choriocarcinoma cells mimics the transcriptional consequences of PE in the human placenta. Here, we created transgenic mouse strains overexpressing human STOX1. Wild-type female mice crossed with transgenic male mice reproduce accurately the symptoms of severe PE: gestational hypertension, proteinuria, and elevated plasma levels of soluble fms-like tyrosine kinase 1 and soluble endoglin. Placental and kidney histology were altered. Symptoms were prevented or alleviated by aspirin treatment. STOX1-overexpressing mice constitute a unique model for studying PE, allow testing therapeutic approaches, and assessing the long-term effects of the preeclamptic syndrome