C-Nap1 mutation affects centriole cohesion and is associated with a Seckel-like syndrome in cattle

Caprine-like Generalized Hypoplasia Syndrome (SHGC) is an autosomal-recessive disorder in Montbéliarde cattle. Affected animals present a wide range of clinical features that include the following: delayed development with low birth weight, hind limb muscular hypoplasia, caprine-like thin head and partial coat depigmentation. Here we show that SHGC is caused by a truncating mutation in the CEP250 gene that encodes the centrosomal protein C-Nap1. This mutation results in centrosome splitting, which neither affects centriole ultrastructure and duplication in dividing cells nor centriole function in cilium assembly and mitotic spindle organization. Loss of C-Nap1-mediated centriole cohesion leads to an altered cell migration phenotype. This discovery extends the range of loci that constitute the spectrum of autosomal primary recessive microcephaly (MCPH) and Seckel-like syndromes

Multilocus variable number of tandem repeat analysis reveals multiple introductions in Spain of Xanthomonas arboricola pv. Pruni, the causal agent of bacterial spot disease of stone fruits and almond

Xanthomonas arboricola pv. pruni is the causal agent of the bacterial spot disease of stone fruits, almond and some ornamental Prunus species. In Spain it was first detected in 2002 and since then, several outbreaks have occurred in different regions affecting mainly Japanese plum, peach and almond, both in commercial orchards and nurseries. As the origin of the introduction(s) was unknown, we have assessed the genetic diversity of 239 X. arboricola pv. pruni strains collected from 11 Spanish provinces from 2002 to 2013 and 25 reference strains from international collections. We have developed an optimized multilocus variable number of tandem repeat analysis (MLVA) scheme targeting 18 microsatellites and five minisatellites. A high discriminatory power was achieved since almost 50% of the Spanish strains were distinguishable, confirming the usefulness of this genotyping technique at small spatio-temporal scales. Spanish strains grouped in 18 genetic clusters (conservatively delineated so that each cluster contained haplotype networks linked by up to quadruple-locus variations). Furthermore, pairwise comparisons among populations from different provinces showed a strong genetic differentiation. Our results suggest multiple introductions of this pathogen in Spain and redistribution through contaminated nursery propagative plant material

Early acute microvascular kidney transplant rejection in the absence of anti-HLA antibodies is associated with preformed IgG antibodies against diverse glomerular endothelial cell antigens

International audienceBACKGROUND: Although anti-HLA antibodies (Abs) cause most antibody-mediated rejections of renal allografts, non-anti-HLA Abs have also been postulated to contribute. A better understanding of such Abs in rejection is needed.METHODS: We conducted a nationwide study to identify kidney transplant recipients without anti-HLA donor-specific Abs who experienced acute graft dysfunction within 3 months after transplantation and showed evidence of microvascular injury, called acute microvascular rejection (AMVR). We developed a crossmatch assay to assess serum reactivity to human microvascular endothelial cells, and used a combination of transcriptomic and proteomic approaches to identify non-HLA Abs.RESULTS: We identified a highly selected cohort of 38 patients with early acute AMVR. Biopsy specimens revealed intense microvascular inflammation and the presence of vasculitis (in 60.5%), interstitial hemorrhages (31.6%), or thrombotic microangiopathy (15.8%). Serum samples collected at the time of transplant showed that previously proposed anti-endothelial cell Abs-angiotensin type 1 receptor (AT1R), endothelin-1 type A and natural polyreactive Abs-did not increase significantly among patients with AMVR compared with a control group of stable kidney transplant recipients. However, 26% of the tested AMVR samples were positive for AT1R Abs when a threshold of 10 IU/ml was used. The crossmatch assay identified a common IgG response that was specifically directed against constitutively expressed antigens of microvascular glomerular cells in patients with AMVR. Transcriptomic and proteomic analyses identified new targets of non-HLA Abs, with little redundancy among individuals.CONCLUSIONS: Our findings indicate that preformed IgG Abs targeting non-HLA antigens expressed on glomerular endothelial cells are associated with early AMVR, and that cell-based assays are needed to improve risk assessments before transplant

Interaction entre des mutants hrp d'Erwinia amylovora, agent du feu bactérien, le parent pathogène et la plante hôte : recherche de mécanismes modulant la compatibilité

Erwinia amylovora is the causal agent of fire blight, a disease that affects Maloideae. This gammaproteobacteria requires a type three secretion system (T3SS) for its pathogenicity. Previous work has shown that avirulent hrp mutant strains of E. amylovora affected in regulatory functions (hrpL and hrpS) protect apple seedlings from developping fire blight symptoms. We investigated molecular mechanisms leading to this protection. In a first part of our work, we studied molecular responses of the protected plant, according to major defense pathways (salicylic acid, jasmonic acid, ethylene) and in the phenylpropanoid pathway. Results show that none of these pathways is particularly induced by Ea hrpL or Ea hrpS mutants. Then, the hypothesis of a direct effect of mutants on the wild type strain has been denied. We tried to trace differential transcripts and proteins between these bacteria through targeted and global approaches (targeted genes vs cDNA-AFLP). Results show that HrpL and HrpS are able to differentially regulate other genes that hrp genes : HrpL negatively regulates flagellar system, chemotaxis and genes related to GSP, and positively regulates one gene of T1SS and one OMP ; HrpS negatively regulates quorum sensing and positively regulates one gene implicated in the synthesis of ethylene. We were particularly interested in flagellar system of E. amylovora. An in silico analysis of flagellar genes led to the discovery that E. amylovora possesses two flagellar systems with distincts flagellins (32 vs 50KDa). The 32KDa flagellin, overexpressed in hrpL mutant, does not display the flg22 peptide classically implicated in elicitation and is not necessary for protection. On the whole, our work does not entirely explain the origin of the plant protection, induced by regulatory hrp mutants, nevertheless it provides new key information on E. amylovora and on the regulation of several genes during the interaction with the host plant.Le feu bactérien des Maloideae est provoqué par Erwinia amylovora, gamma-protéobactérie dont le pouvoir pathogène repose un système de sécrétion de type trois (T3SS). Des travaux antérieurs ont révélés que des mutants hrp de régulation de ce système (hrpL, hrpS), avirulents, sont capables de protéger la plante d'une infection par la souche sauvage. Nous avons d'abord voulu savoir si la protection est due à une induction de défenses chez la plante. L'étude de l'expression de gènes de défense dépendants des voies de l'acide salicylique, de l'acide jasmonique, de l'éthylène et des phénylpropanoïdes montre qu'aucune de ces voies n'est particulièrement induite par les mutants de régulation. Puis après avoir écarté l'hypothèse d'un effet direct des mutants sur la souche sauvage, nous avons recherché des différences au niveau protéique et surtout transcriptomique entre ces bactéries par des démarches avec et sans a priori (gènes-cibles vs cDNAAFLP). Les résultats montrent que HrpS et HrpL sont capables de réguler différentiellement d'autres gènes que les gènes hrp : HrpL régule négativement les gènes flagellaires, le chimiotactisme et un gène du GSP, et positivement un gène du T1SS et une OMP ; HrpS régule négativement le quorum sensing et positivement un gène potentiellement impliqué dans la synthèse de l'éthylène. Nous avons particulièrement approfondi le système flagellaire d'E. amylovora. Une analyse bioinformatique a révélé que cette bactérie possède deux systèmes flagellaires, secrétant deux flagellines distinctes (32 vs 50 KDa). La flagelline de 32 KDa, réprimée par HrpL, ne joue pas de rôle majeur dans la protection et ne possède pas l'épitope flg22 impliqué dans l'immunité des plantes. Si notre travail n'élucide pas complètement l'origine de la protection conférée par les mutants de régulation, il apporte des informations nouvelles sur E. amylovora et sur la régulation de certains de ses gènes au cours de l'interaction avec son hôte

Implants cochléaires chez l'adulte et l'enfant sourds (description, réglementation et fonctionnement)

TOURS-BU Sciences Pharmacie (372612104) / SudocSudocFranceF

Interaction entre des mutants hrp d'Erwinia amylovora, agent du feu bactérien, le parent pathogène et la plante hôte (recherche de mécanismes modulant la compatibilité)

Le feu bactérien des Maloideae est provoqué par Erwinia amylovora, gamma-protéobactérie dont le pouvoir pathogène repose un système de sécrétion de type trois (T3SS). Des travaux antérieurs ont révélés que des mutants hrp de régulation de ce système (hrpL, hrpS), avirulents, sont capables de protéger la plante d'une infection par la souche sauvage. Nous avons d'abord voulu savoir si la protection est due à une induction de défenses chez la plante. L'étude de l'expression de gènes de défense dépendants des voies de l'acide salicylique, de l'acide jasmonique, de l'éthylène et des phénylpropanoïdes montre qu'aucune de ces voies n'est particulièrement induite par les mutants de régulation. Puis après avoir écarté l'hypothèse d'un effet direct des mutants sur la souche sauvage, nous avons recherché des différences au niveau protéique et surtout transcriptomique entre ces bactéries par des démarches avec et sans a priori (gènes-cibles vs cDNAAFLP). Les résultats montrent que HrpS et HrpL sont capables de réguler différentiellement d'autres gènes que les gènes hrp : HrpL régule négativement les gènes flagellaires, le chimiotactisme et un gène du GSP, et positivement un gène du T1SS et une OMP ; HrpS régule négativement le quorum sensing et positivement un gène potentiellement impliqué dans la synthèse de l'éthylène. Nous avons particulièrement approfondi le système flagellaire d'E. amylovora. Une analyse bioinformatique a révélé que cette bactérie possède deux systèmes flagellaires, secrétant deux flagellines distinctes (32 vs 50 KDa). La flagelline de 32 KDa, réprimée par HrpL, ne joue pas de rôle majeur dans la protection et ne possède pas l'épitope flg22 impliqué dans l'immunité des plantes. Si notre travail n'élucide pas complètement l'origine de la protection conférée par les mutants de régulation, il apporte des informations nouvelles sur E. amylovora et sur la régulation de certains de ses gènes au cours de l'interaction avec son hôte.Erwinia amylovora is the causal agent of fire blight, a disease that affects Maloideae. This gammaproteobacteria requires a type three secretion system (T3SS) for its pathogenicity. Previous work has shown that avirulent hrp mutant strains of E. amylovora affected in regulatory functions (hrpL and hrpS) protect apple seedlings from developping fire blight symptoms. We investigated molecular mechanisms leading to this protection. In a first part of our work, we studied molecular responses of the protected plant, according to major defense pathways (salicylic acid, jasmonic acid, ethylene) and in the phenylpropanoid pathway. Results show that none of these pathways is particularly induced by Ea hrpL or Ea hrpS mutants. Then, the hypothesis of a direct effect of mutants on the wild type strain has been denied. We tried to trace differential transcripts and proteins between these bacteria through targeted and global approaches (targeted genes vs cDNA-AFLP). Results show that HrpL and HrpS are able to differentially regulate other genes that hrp genes : HrpL negatively regulates flagellar system, chemotaxis and genes related to GSP, and positively regulates one gene of T1SS and one OMP ; HrpS negatively regulates quorum sensing and positively regulates one gene implicated in the synthesis of ethylene. We were particularly interested in flagellar system of E. amylovora. An in silico analysis of flagellar genes led to the discovery that E. amylovora possesses two flagellar systems with distincts flagellins (32 vs 50KDa). The 32KDa flagellin, overexpressed in hrpL mutant, does not display the flg22 peptide classically implicated in elicitation and is not necessary for protection. On the whole, our work does not entirely explain the origin of the plant protection, induced by regulatory hrp mutants, nevertheless it provides new key information on E. amylovora and on the regulation of several genes during the interaction with the host plant.ANGERS-BU Lettres et Sciences (490072106) / SudocSudocFranceF

Evaluation of the AmplifyRP XRT+ Kit for the Detection of Xylella fastidiosa by Recombinase Polymerase Amplification

Xylella fastidiosa is a quarantine priority pest in Europe and several other countries as it represents a major threat to many cultivated and wild plants. Early detection of the pathogen is needed to reduce potential losses and to stop the bacterial dissemination. Very few molecular methods are available for rapid field detection to identify the pathogen. Here, we evaluated a new rapid commercial detection test called AmplifyRP, based on molecular recombinase polymerase amplification (RPA). The AmplifyRP test was compared with the quantitative PCR (qPCR) Harper's assay, which represents the standard method used in most laboratories all over the world. Specificity was tested in vitro on a panel of target and nontarget strains. Additionally, the sensitivity of the RPA test was tested on X. fastidiosa genomic DNA, and the selectivity was compared between different host plant matrices spiked with X. fastidiosa cell suspensions. Although the qPCR assay showed a higher sensitivity than the RPA test, the latter appeared to be a very specific, rapid, and portable technique for which no skills are required to proceed. These findings should enable growers and inspectors to choose an appropriate diagnostic method. [Graphic: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license

Production of transgenic pear plants expressing ferritin gene with the aim to reduce fire blight susceptibility

International audienceFire blight caused by the bacteria Erwinia amylovora is one of the most important diseases of pear. This causal agent produces a siderophore (desferrioxamine), which was identified as one of its virulence factors. This protein enables the bacteria to overcome conditions of iron limitation encountered in host tissues, and may also protect the bacteria against active oxygen species. Previous experiments indicate that the use of an iron chelator protein, encoded by the bovine lactoferrin gene, reduces fire blight symptoms in some transgenic pear clones. The aim of the present work is to test the ability of a more efficient iron chelator, plant ferritin, to reduce fire blight susceptibility in pear. In the literature, ferritin genes have been overexpressed under the control of a constitutive promoter in different transgenic plant species for various purposes. In several cases, the constitutive expression of ferritin produced negative effects such as reduced growth and chlorophyll content. Therefore, we decided to place the exogenous ferritin gene from pea under the control of a pathogen inducible promoter (sgd24) in comparison with a constitutive promoter (CaMV 35S). Two pear varieties, 'Conference' (CF) and 'Passe-Crassane' (PC) were transformed using both constructs. Transformation rates depended on variety and construct. They were respectively of 12 and 4.3% for CF and PC using the sgd24-ferritin construct. Only PC was transformed with the 35S-ferritin construct, with a transformation rate of 2%. First analyses of the transgenic clones by RT-PCR showed the expression of pea ferritin in both constructs and in all clones. The transgenic clones were acclimatized in greenhouse and exhibited normal growth. Quantification of ferritin gene expression, ferritin protein accumulation, and evaluation of fire blight resistance are underway

Antibodies targeting circulating protective molecules in lupus nephritis: Interest as serological biomarkers

International audienceLupus nephritis (LN) is one of the most frequent and severe manifestations of systemic lupus erythematosus (SLE), considered as the major predictor of poor prognosis. An early diagnosis of LN is a real challenge in the management of SLE and has an important implication in guiding treatments. In clinical practice, conventional parameters still lack sensitivity and specificity for detecting ongoing disease activity in lupus kidneys and early relapse of nephritis. LN is characterized by glomerular kidney injury, essentially due to deposition of immune complexes involving autoantibodies against cellular components and circulating proteins. One of the possible mechanisms of induction of autoantibodies in SLE is a defect in apoptotic cells clearance and subsequent release of intracellular autoantigens. Autoantibodies against soluble protective molecules involved in the uptake of dying cells, including complement proteins and pentraxins, have been described. In this review, we present the main autoantibodies found in LN, with a focus on the antibodies against these protective molecules. We also discuss their pathogenic role and conclude with their potential interest as serological biomarkers in LN