Studies on legume receptors for Nod and Myc symbiotic signals

Les symbioses rhizobienne et mycorhizienne à arbuscules sont deux endosymbioses racinaires jouant des rôles importants dans le développement des plantes en améliorant leur nutrition minérale. Les lipo-chitooligosaccharides (LCOs), produits par les bacteries Rhizobia et les champignons mycorhiziens, sont essentiels pour l'établissement de la symbiose rhizobienne et stimulent la mycorhization. Chez la légumineuse Medicago truncatula, trois récepteurs-like kinase à motifs lysin (LysM), LYR3, NFP et LYK3 sont impliqués dans la perception des LCOs. Le travail présenté a eu pour objectif la caractérisation biochimique de ces récepteurs et leurs applications potentielles. Les orthologues de LYR3 de M. truncatula ont été clonés et se sont tous révélés, à l'exception de celui du lupin, capables d'établir une interaction d'affinité élevée avec les LCOs mais pas avec les chitooligosaccharides de structure apparentée. Afin de mieux comprendre les bases moléculaires de la reconnaissance des LCOs, des échanges de domaine entre les protéines LYR3 de lupin et de Medicago ont été effectués et ont révélé l'importance du troisième domaine LysM dans l'interaction. L'exploitation des capacités de reconnaissance des LCOs par LYR3 à des fins biotechnologiques a été évaluée à l'aide de récepteurs chimériques constitués du domaine extracellulaire de LYR3 et du domaine kinase des récepteurs immunitaires AtCERK1 et EFR. Il est apparu que LYR3 peut être utilisé pour élaborer des récepteurs chimériques mais leur mode d'activation reste à optimiser. Enfin l'étude des deux récepteurs symbiotiques NFP et LYK3 suggère qu'ils sont régulés par phosphorylation suite au traitement par les signaux symbiotiques. L'ensemble de ce travail apporte un éclairage nouveau sur les mécanismes de perception des LCOs et sur les modifications associées à leurs récepteurs qui en résultent.Arbuscular mycorrhization and rhizobial nodulation are two major root endosymbioses which play important roles in plant development by improving their mineral nutrition. Produced by Rhizobia bacteria and mycorrhizal fungi, lipo-chitooligosaccharides (LCOs) were shown to be essential for the formation of the rhizobial symbiosis and to have stimulatory effects on mycorrhization. In the legume Medicago truncatula three lysin motif (LysM) receptor-like kinases LYR3, NFP and LYK3 have been shown to be involved in LCO perception. Here work is presented aimed at the biochemical characterization and application of these important receptor proteins. Cloned from several legume species orthologs of M. truncatula LYR3, except from lupin, were shown to bind LCOs with high affinity, but not structurally-related chitooligosaccharides (COs). Domain swaps between the lupin and Medicago proteins were used as a tool to decipher the molecular basis of LCO recognition and revealed the importance of the third LysM domain for LCO binding. The possibility of exploiting the LCO-binding capacity of LYR3 in biotechnology, through the composition of chimeric receptors, was investigated by combining together the extracellular domain of LYR3 protein with the kinases of Arabidopsis thaliana immune receptors, AtCERK1 and EFR. The results suggest that LYR3 could be used for constructing biologically active chimeric proteins whose mode of activation needs to be improved. Finally studies on the two LysM symbiotic receptors NFP and LYK3 suggest that they are regulated by changes in their phosphorylation after symbiotic treatments. Together this work brings light on the mechanisms underlying LCO perception and the modifications that receptors undergo after their treatment with LCO

How to Boost Face Recognition with StyleGAN?

State-of-the-art face recognition systems require vast amounts of labeled training data. Given the priority of privacy in face recognition applications, the data is limited to celebrity web crawls, which have issues such as limited numbers of identities. On the other hand, self-supervised revolution in the industry motivates research on the adaptation of related techniques to facial recognition. One of the most popular practical tricks is to augment the dataset by the samples drawn from generative models while preserving the identity. We show that a simple approach based on fine-tuning pSp encoder for StyleGAN allows us to improve upon the state-of-the-art facial recognition and performs better compared to training on synthetic face identities. We also collect large-scale unlabeled datasets with controllable ethnic constitution -- AfricanFaceSet-5M (5 million images of different people) and AsianFaceSet-3M (3 million images of different people) -- and we show that pretraining on each of them improves recognition of the respective ethnicities (as well as others), while combining all unlabeled datasets results in the biggest performance increase. Our self-supervised strategy is the most useful with limited amounts of labeled training data, which can be beneficial for more tailored face recognition tasks and when facing privacy concerns. Evaluation is based on a standard RFW dataset and a new large-scale RB-WebFace benchmark. The code and data are made publicly available at https://github.com/seva100/stylegan-for-facerec.Comment: 16 pages, 9 figures, 11 tables; accepted to ICCV 202

Etude des récepteurs des signaux symbiotiques Nod et Myc chez les légumineuses

Arbuscular mycorrhization and rhizobial nodulation are two major root endosymbioses which play important roles in plant development by improving their mineral nutrition. Produced by Rhizobia bacteria and mycorrhizal fungi, lipo-chitooligosaccharides (LCOs) were shown to be essential for the formation of the rhizobial symbiosis and to have stimulatory effects on mycorrhization. In the legume Medicago truncatula three lysin motif (LysM) receptor-like kinases LYR3, NFP and LYK3 have been shown to be involved in LCO perception. Here work is presented aimed at the biochemical characterization and application of these important receptor proteins. Cloned from several legume species orthologs of M. truncatula LYR3, except from lupin, were shown to bind LCOs with high affinity, but not structurally-related chitooligosaccharides (COs). Domain swaps between the lupin and Medicago proteins were used as a tool to decipher the molecular basis of LCO recognition and revealed the importance of the third LysM domain for LCO binding. The possibility of exploiting the LCO-binding capacity of LYR3 in biotechnology, through the composition of chimeric receptors, was investigated by combining together the extracellular domain of LYR3 protein with the kinases of Arabidopsis thaliana immune receptors, AtCERK1 and EFR. The results suggest that LYR3 could be used for constructing biologically active chimeric proteins whose mode of activation needs to be improved. Finally studies on the two LysM symbiotic receptors NFP and LYK3 suggest that they are regulated by changes in their phosphorylation after symbiotic treatments. Together this work brings light on the mechanisms underlying LCO perception and the modifications that receptors undergo after their treatment with LCO.Les symbioses rhizobienne et mycorhizienne à arbuscules sont deux endosymbioses racinaires jouant des rôles importants dans le développement des plantes en améliorant leur nutrition minérale. Les lipo-chitooligosaccharides (LCOs), produits par les bacteries Rhizobia et les champignons mycorhiziens, sont essentiels pour l'établissement de la symbiose rhizobienne et stimulent la mycorhization. Chez la légumineuse Medicago truncatula, trois récepteurs-like kinase à motifs lysin (LysM), LYR3, NFP et LYK3 sont impliqués dans la perception des LCOs. Le travail présenté a eu pour objectif la caractérisation biochimique de ces récepteurs et leurs applications potentielles. Les orthologues de LYR3 de M. truncatula ont été clonés et se sont tous révélés, à l'exception de celui du lupin, capables d'établir une interaction d'affinité élevée avec les LCOs mais pas avec les chitooligosaccharides de structure apparentée. Afin de mieux comprendre les bases moléculaires de la reconnaissance des LCOs, des échanges de domaine entre les protéines LYR3 de lupin et de Medicago ont été effectués et ont révélé l'importance du troisième domaine LysM dans l'interaction. L'exploitation des capacités de reconnaissance des LCOs par LYR3 à des fins biotechnologiques a été évaluée à l'aide de récepteurs chimériques constitués du domaine extracellulaire de LYR3 et du domaine kinase des récepteurs immunitaires AtCERK1 et EFR. Il est apparu que LYR3 peut être utilisé pour élaborer des récepteurs chimériques mais leur mode d'activation reste à optimiser. Enfin l'étude des deux récepteurs symbiotiques NFP et LYK3 suggère qu'ils sont régulés par phosphorylation suite au traitement par les signaux symbiotiques. L'ensemble de ce travail apporte un éclairage nouveau sur les mécanismes de perception des LCOs et sur les modifications associées à leurs récepteurs qui en résultent

The cadmium-tolerant pea (Pisum sativum L.) mutant SGECd(t) is more sensitive to mercury:assessing plant water relations

Heavy metals have multiple effects on plant growth and physiology, including perturbation of plant water status. These effects were assessed by exposing the unique Cd-tolerant and Cd-accumulating pea (Pisum sativum L.) mutant SGECd(t) and its wild-type (WT) line SGE to either cadmium (1, 4 mu M CdCl2) or mercury (0.5, 1, 2 mu M HgCl2) in hydroponic culture for 12 days. When exposed to Cd, SGECd(t) accumulated more Cd in roots, xylem sap, and shoot, and had considerably more biomass than WT plants. WT plants lost circa 0.2 MPa turgor when grown in 4 mu M CdCl2, despite massive decreases in whole-plant transpiration rate and stomatal conductance. In contrast, root Hg accumulation was similar in both genotypes, but WT plants accumulated more Hg in leaves and had a higher stomatal conductance, and root and shoot biomass compared with SGECd(t). Shoot excision resulted in greater root-pressure induced xylem exudation of SGECd(t) in the absence of Cd or Hg and following Cd exposure, whereas the opposite response or no genotypic differences occurred following Hg exposure. Exposing plants that had not been treated with metal to 50 mu M CdCl2 for 1 h increased root xylem exudation of WT, whereas 50 mu M HgCl2 inhibited and eliminated genotypic differences in root xylem exudation, suggesting differences between WT and SGECd(t) plants in aquaporin function. Thus, root water transport might be involved in mechanisms of increased tolerance and accumulation of Cd in the SGECd(t) mutant. However, the lack of cross-tolerance to Cd and Hg stress in the mutant indicates metal-specific mechanisms related to plant adaptation

Duct Adenoma of the Breast as Background Process for Cholesterol Granuloma: Case Report and Literature Review

Cholesterol granuloma (CG) is an extremely rare benign condition that should be considered in the differential diagnosis of breast lesions suspected of being malignant. We present a case of a 55-year-old woman who presented with a nodule mass in the upper external quadrant of the right breast on a routine mammography examination. The described case is noticeable by the combination of multiple CGs in the lungs (with arterial hypertension and thrombocytopenia as a background) with breast presentation, which was associated ductal adenoma

Molecular basis of lipo-chitooligosaccharide recognition by the lysin motif receptor-like kinase LYR3 in legumes

International audienceLYR3 [LysM (lysin motif) receptor-like kinase 3] of Medicago truncatula is a high-affinity binding protein for symbiotic LCO (lipo-chitooligosaccharide) signals, produced by rhizobia bacteria and arbuscular mycorrhizal fungi. The present study shows that LYR3 from several other legumes, but not from two Lupinus species which are incapable of forming the mycorrhizal symbiosis, bind LCOs with high affinity and discriminate them from COs (chitooligosaccharides). The biodiversity of these proteins and the lack of binding to the Lupinus proteins were used to identify features required for high-affinity LCO binding. Swapping experiments between each of the three LysMs of the extracellular domain of the M. truncatula and Lupinus angustifolius LYR3 proteins revealed the crucial role of the third LysM in LCO binding. Site-directed mutagenesis identified a tyrosine residue, highly conserved in all LYR3 LCO-binding proteins, which is essential for high-affinity binding. Molecular modelling suggests that it may be part of a hydrophobic tunnel able to accommodate the LCO acyl chain. The lack of conservation of these features in the binding site of plant LysM proteins binding COs provides a mechanistic explanation of how LCO recognition might differ from CO perception by structurally related LysM receptors

Urea salts with 1-hydroxyethylidene diphosphonic acid

The reaction of urea with 1-hydroxyethylidene diphosphonic acid in the ratios of 1 : 1, 1 : 2, 1 : 3 wasfirst studied. As a result of the reactions, the corresponding 1 : 2 or 2 : 1 salts were formed, which can exhibitbiological activity. The synthesized compounds were characterized by atomic emission spectroscopy, IR and NMR spectroscopy. According to atomic emission analysis, an increase in the amount of urea from 3 moles or more per 1 mole of 1-hydroxyethylidene diphosphonic acid does not cause an increase in the urea content in the final products. According to NMR spectroscopy data, compounds in the formation of which phosphoryl groups of 1-hydroxyethylidene diphosphonic acid are involved are in dynamic equilibrium salt–free acid

Role of a receptor-like kinase K1 in pea Rhizobium symbiosis development

International audienceMain conclusion The LysM receptor-like kinase K1 is involved in regulation of pea-rhizobial symbiosis development. The ability of the crop legume Pisum sativum L. to perceive the Nod factor rhizobial signals may depend on several receptors that differ in ligand structure specificity. Identification of pea mutants defective in two types of LysM receptor-like kinases (LysM-RLKs), SYM10 and SYM37, featuring different phenotypic manifestations and impaired at various stages of symbiosis development, corresponds well to this assumption. There is evidence that one of the receptor proteins involved in symbiosis initiation, SYM10, has an inactive kinase domain. This implies the presence of an additional component in the receptor complex, together with SYM10, that remains unknown. Here, we describe a new LysM-RLK, K1, which may serve as an additional component of the receptor complex in pea. To verify the function of K1 in symbiosis, several P. sativum non-nodulating mutants in the k1 gene were identified using the TILLING approach. Phenotyping revealed the blocking of symbiosis development at an appropriately early stage, strongly suggesting the importance of LysM-RLK K1 for symbiosis initiation. Moreover, the analysis of pea mutants with weaker phenotypes provides evidence for the additional role of K1 in infection thread distribution in the cortex and rhizobia penetration. The interaction between K1 and SYM10 was detected using transient leaf expression in Nicotiana benthamiana and in the yeast two-hybrid system. Since the possibility of SYM10/SYM37 complex formation was also shown, we tested whether the SYM37 and K1 receptors are functionally interchangeable using a complementation test. The interaction between K1 and other receptors is discussed