The Arabidopsis thaliana-Alternaria brassicicola pathosystem: A model interaction for investigating seed transmission of necrotrophic fungi

Seed transmission constitutes a major component of the parasitic cycle for several fungal pathogens. However, very little is known concerning fungal or plant genetic factors that impact seed transmission and mechanisms underlying this key biological trait have yet to be clarified. Such lack of available data could be probably explained by the absence of suitable model pathosystem to study plant-fungus interactions during the plant reproductive phase

Lack of Adiponectin Drives Hyperosteoclastogenesis in Lipoatrophic Mice.

Long bones from mammals host blood cell formation and contain multiple cell types, including adipocytes. Physiological functions of bone marrow adipocytes are poorly documented. Herein, we used adipocyte-deficient PPARγ-whole body null mice to investigate the consequence of total adipocyte deficiency on bone homeostasis in mice. We first highlighted the dual bone phenotype of PPARγ null mice: one the one hand, the increased bone formation and subsequent trabecularization extending in the long bone diaphysis, due to the well-known impact of PPARγ deficiency on osteoblasts formation and activity; on the other hand, an increased osteoclastogenesis in the cortical bone. We then further explored the cause of this unexpected increased osteoclastogenesis using two independent models of lipoatrophy, which recapitulated this phenotype. This demonstrates that hyperosteoclastogenesis is not intrinsically linked to PPARγ deficiency, but is a consequence of the total lipodystrophy. We further showed that adiponectin, a cytokine produced by adipocytes and mesenchymal stromal cells is a potent inhibitor of osteoclastogenesis in vitro and in vivo. Moreover, pharmacological activation of adiponectin receptors by the synthetic agonist AdipoRon inhibited mature osteoclast activity both in mouse and human cells by blocking podosome formation through AMPK activation. Finally, we demonstrated that AdipoRon treatment blocks bone erosion in vivo in a murine model of inflammatory bone loss, providing potential new approaches to treat osteoporosis

Outcome after failure of allogeneic hematopoietic stem cell transplantation in children with acute leukemia: a study by the Société Francophone de Greffe de Moelle et de Thérapie Cellulaire (SFGM-TC)

Allogeneic hematopoietic stem cell transplantation (SCT) contributes to improved outcome in childhood acute leukemia (AL). However, therapeutic options are poorly defined in case of post-transplantation relapse. We aimed to compare treatment strategies in 334 consecutive children with acute leukemia relapse or progression after SCT in a recent ten-year period. Data could be analyzed in 288 patients (157 ALL, 123 AML and 8 biphenotypic AL) with a median age of 8.16 years at transplantation. The median delay from first SCT to relapse or progression was 182 days. The treatment consisted in chemotherapy alone (n=108), chemotherapy followed by second SCT (n=70), supportive/palliative care (n=67), combination of chemotherapy and DLI (n=30), or isolated reinfusion of donor lymphocytes (DLI) (n=13). The median OS duration after relapse was 164 days and differed according to therapy: DLI after chemotherapy = 385 d, second allograft = 391d, chemotherapy = 174d, DLI alone = 140d, palliative care = 43d. A second SCT or a combination of chemotherapy and donor lymphocytes infusion yielded similar outcome (HR=0.85, p=0.53) unlike chemotherapy alone (HR 1.43 p=0.04), palliative care (HR=4.24, p<0.0001) or isolated DLI (HR=1,94, p<0.04). Despite limitations in this retrospective setting, strategies including immunointervention appear superior to other approaches, mostly in AML

Etude de la transmission du champignon Alternaria brassicicola à la semence d’Arabidopsis thaliana

National audienc

Roles of hydrophilin-like protein in the filamentous fungi Alternaria brassicicola

During their life cycle, fungi face adverse environmental conditions associated with alterations in water status. Phytopathogenic fungi are faced with this type of stress during the infection process, especially when they colonize seeds. Although these organisms are particularly effective to adapt to these water potential decreases, these coping mechanisms are so far very poorly described, particularly in filamentous fungi. Alternaria brassicicola is a seed-borne fungal pathogen responsible for the black spot disease on Brassicaceae plants. Alteration of Brassicaceae seed quality is one of the most damaging effects of the black spot. Beyond contribution to pathogen dissemination, the presence of the fungus on the seeds compromises seedling germination and survival. To better understand the determinism of fungus transmission to seeds, we previously established a reliable Arabidopsis-based pathosystem allowing investigations of A. brassicicola transmission to seeds. In particular, we showed that two mutants strain ∆abhog and ∆abnik exhibiting higher susceptibility to osmotic and water stress were highly impaired in seed transmission ability. Transcriptomic analyzes, carried out under different experimental in vitro conditions inducing these types of stress (addition of sorbitol or Poly Ethylene Glycol (PEG) or by incubation under low relative humidity (1% RH)), allowed us to identify additional mechanisms potentially involved in the fungal adaptive responses. In particular, these analyzes revealed a pool of over-expressed genes encoding putative proteins which share physiochemical features typical of hydrophilin-like proteins. We initiated studies of some of these hydrophilins by generating respective Knock-Out mutants. Functional studies has been carried out to determine whether these mutants were impaired in their adaptive response to water stress and other types of stress (such as oxidative stress) and whether hydrophilins are involved in pathogenicity. Additional transcriptomic assays conducted on ∆abhog and ∆abnik strain growth under sorbitol exposure revealed that numerous hydrophilins are regulated by these two genes

Influencia de la raza, estación del año y etapa de lactación sobre el contenido mineral de leche de búfalas

El objetivo de este estudio fue determinar la composición mineral de la leche de búfala producida en la Provincia de Corrientes, Argentina, así como investigar variaciones atribuibles al estadio de lactación, época del año y raza. Se trabajó con leche de 25 búfalas de razas Murrah, Mediterránea, Jafarabadi y mestizas ½ Murrah x ½ Mediterránea, de segunda a séptima lactación, durante 19 meses, totalizando 105 muestras. Los animales pertenecían a un tambo localizado en una región de clima subtropical húmedo, con precipitaciones anuales de 1.690 mm y temperatura media anual de 22°C. Se obtuvieron valores medios para Ca (1,12 ± 0,40 g.kg–1), P (0,99 ± 0,32 g.kg–1), Mg (0,08 ± 0,02 g.kg–1), K (0,92 ± 0,25 g.kg–1), Na (0,35 ± 0,11 g.kg–1), Cu (0,35 ± 0,16 mg.kg–1), Mn (0,27 ± 0,10 mg.kg–1), Zn (4,10 ± 1,40 mg.kg–1) y Fe (1,61 ± 0,61 mg.kg–1). Estos parámetros no revelaron diferencias significativas atribuibles a la raza de los animales con excepción del Mg. La época del año afectó la composición de los minerales, con excepción de Mg y Zn. Las etapas de lactación influenciaron sobre los valores de Ca, P, K y Cu. Los resultados obtenidos indican que el contenido mineral en leche de búfalas resulta considerablemente influenciado por factores regionales

Is the dark matter interpretation of the EGRET gamma excess compatible with antiproton measurements?

We investigate the internal consistency of the halo dark matter model which has been proposed by de Boer et al. to explain the excess of diffuse galactic gamma rays observed by the EGRET experiment. Any model based on dark matter annihilation into quark jets, such as the supersymmetric model proposed by de Boer et al., inevitably also predicts a primary flux of antiprotons from the same jets. Since propagation of the antiprotons in the unconventional, disk-dominated type of halo model used by de Boer et al. is strongly constrained by the measured ratio of boron to carbon nuclei in cosmic rays, we investigate the viability of the model using the DarkSUSY package to compute the gamma-ray and antiproton fluxes. We are able to show that their model is excluded by a wide margin from the measured flux of antiprotons. We therefore find that a model of the type suggested by Moskalenko et al., where the intensities of protons and electrons in the cosmic rays vary with galactic position, is far more plausible to explain the gamma excess.Comment: 14 pages, 5 figures. Matches published versio