The composition of airborne and grain-dust fungal communities is shaped at regional scale by plant genotypes and farming practices

Chronic exposure to airborne fungi has been associated with different respiratory symptoms and pathologies in occupational populations, such as grain workers. However, the homogeneity in the fungal species composition of these bioaerosols on a large geographical scale and the different drivers that shape these fungal communities remain unclear. In this study, the diversity of fungi in grain dust and in the aerosols released during harvesting was determined across 96 sites at a geographical scale of 560 km(2) along an elevation gradient of 500 m by tag-encoded 454-pyrosequencing of the internal transcribed spacer (ITS) sequences. Associations between the structure of fungal communities in the grain dust and different abiotic (farming system, soil characteristics, geographic and climatic parameters) and biotic (wheat cultivar, previous crop culture) factors were explored. These analyses revealed a strong relationship between the airborne and grain dust fungal communities and showed the presence of allergenic and mycotoxigenic species in most samples, which highlights the potential contribution of these fungal species to work-related respiratory symptoms of grain workers. The farming system was the major driver of the alpha and beta phylogenetic diversity of fungal communities. In addition, elevation and soil CaCO3 concentrations shaped the alpha diversity whereas wheat cultivar, cropping history and the number of freezing days per year shaped the taxonomic beta diversity of these communities.

Barn owl feathers as biomonitors of mercury: sources of variation in sampling procedures.

Given their central role in mercury (Hg) excretion and suitability as reservoirs, bird feathers are useful Hg biomonitors. Nevertheless, the interpretation of Hg concentrations is still questioned as a result of a poor knowledge of feather physiology and mechanisms affecting Hg deposition. Given the constraints of feather availability to ecotoxicological studies, we tested the effect of intra-individual differences in Hg concentrations according to feather type (body vs. flight feathers), position in the wing and size (mass and length) in order to understand how these factors could affect Hg estimates. We measured Hg concentration of 154 feathers from 28 un-moulted barn owls (Tyto alba), collected dead on roadsides. Median Hg concentration was 0.45 (0.076-4.5) mg kg(-1) in body feathers, 0.44 (0.040-4.9) mg kg(-1) in primary and 0.60 (0.042-4.7) mg kg(-1) in secondary feathers, and we found a poor effect of feather type on intra-individual Hg levels. We also found a negative effect of wing feather mass on Hg concentration but not of feather length and of its position in the wing. We hypothesize that differences in feather growth rate may be the main driver of between-feather differences in Hg concentrations, which can have implications in the interpretation of Hg concentrations in feathers. Finally, we recommend that, whenever possible, several feathers from the same individual should be analysed. The five innermost primaries have lowest mean deviations to both between-feather and intra-individual mean Hg concentration and thus should be selected under restrictive sampling scenarios.

Absence of nonhematopoietic MHC class II expression protects mice from experimental autoimmune myocarditis.

Experimental autoimmune myocarditis (EAM) is a CD4(+) T-cell-mediated model of human inflammatory dilated cardiomyopathies. Heart-specific CD4(+) T-cell activation is dependent on autoantigens presented by MHC class II (MHCII) molecules expressed on professional APCs. In this study, we addressed the role of inflammation-induced MHCII expression by cardiac nonhematopoietic cells on EAM development. EAM was induced in susceptible mice lacking inducible expression of MHCII molecules on all nonhematopoietic cells (pIV-/- K14 class II transactivator (CIITA) transgenic (Tg) mice) by immunization with α-myosin heavy chain peptide in CFA. Lack of inducible nonhematopoietic MHCII expression in pIV-/- K14 CIITA Tg mice conferred EAM resistance. In contrast, cardiac pathology was induced in WT and heterozygous mice, and correlated with elevated cardiac endothelial MHCII expression. Control mice with myocarditis displayed an increase in infiltrating CD4(+) T cells and in expression of IFN-γ, which is the major driver of nonhematopoietic MHCII expression. Mechanistically, IFN-γ neutralization in WT mice shortly before disease onset resulted in reduced cardiac MHCII expression and pathology. These findings reveal a previously overlooked contribution of IFN-γ to induce endothelial MHCII expression in the heart and to progress cardiac pathology during myocarditis.

Entrepreneurial Initiative Selling Within Organizations: Towards a More Comprehensive Motivational Framework

We develop and test a motivational framework to explain the intensity with which individuals sell entrepreneurial initiatives within their organizations. Initiative selling efforts may be driven by several factors that hitherto have not been given full consideration: initiative characteristics, individuals' anticipation of rewards, and their level of dissatisfaction. On the basis of a survey in a mail service firm of 192 managers who proposed an entrepreneurial initiative, we find that individuals' reported intensity of their selling efforts with respect to that initiative is greater when they (1) believe that the organizational benefits of the initiative are high, (2) perceive that the initiative is consistent with current organizational practices (although this effect is weak), (3) believe that their immediate organizational environment provides extrinsic rewards for initiatives, and (4) are satisfied with the current organizational situation. These findings extend previous expectancy theory-based explanations of initiative selling (by considering the roles of initiative characteristics and that of initiative valence for the proponent) and show the role of satisfaction as an important motivational driver for initiative selling.

MALT1 activity controls Kaposi's sarcoma-associated herpesvirus latency and growth of primary effusion lymphoma

The identification of cancer-specific enzymatic activities that can be therapeutically targeted is key to the development of suitable anti-cancer drugs. Primary effusion lymphoma (PEL) is a rare and incurable malignancy that can occur in immunodeficient patients as a consequence of latent infection of B-cells with Kaposi's sarcoma-associated herpesvirus, KSHV (also known as human herpesvirus-8, HHV8). Malignant growth of KSHV-infected B cells requires the constitutive activity of the transcription factor NF-KB, which controls expression of viral genes required for maintenance of viral latency and suppression of the viral lytic program. Here we identify the protease mucosa-associated lymphoid tissue transformation protein 1 (MALTI), a key driver of NF-KB activation in lymphocytes, as an essential component in KSHV-dependent NF-KB activation and growth of latently infected PEL cell lines. Inhibition of the MALTI protease activity induced a switch from the latent to the lytic stage of viral infection, and led to reduced growth and survival of PEL cell lines in vitro and in a xenograft model. These results demonstrate a key role for the proteolytic activity of MALTI in PEL, and provide a rationale for the pharmacological targeting of MALTI in PEL therapy. -- L'identification d'activités enzymatiques propre au cancer est clé dans le développement des nouvaux médicaments anti-cancer. Le lymphome primitif des séreuses est un lymphome rare et incurable qui peut se developer chez les patients immunodéficients. Il est la conséquence d'une infection latente des cellules B, dûe à l'herpes virus 8, plus connu comme herpes virus associé au sarcome de Kaposi (KSHV). La croissance maligne des cellules B infecteés par KSHV requière l'activité constitutive du facteur de transcription NF-KB qui contrôle l'expression des genes viraux requis pour la maintenance latente et la suppression du programme de lyse du virus. Avec cette étude, nous avons identifié la protease MALTI comme un composant essentiel dans l'activation de NF-KB dans les cellules B du lymphome primitif des séreuses. L'inhibition de l'activité de la protéase MALTI induit un virement de la phase latente à la phase lytique du KSHV et conduit à une reduction de la viabilité des cellules tumorales in vitro et dans un modèle de xénogreffe. Ces résultats démontrent un rôle clé pour l'activité protéolytique de MALTI dans le développement du lymphome primitif des séreuses et soutiennent l'idée que MALTI pourrait être une cible pharmacologique dans la thérapie de cette forme rare du lymphome.

Ecological change predicts population dynamics and genetic diversity over 120 000 years.

While ecological effects on short-term population dynamics are well understood, their effects over millennia are difficult to demonstrate and convincing evidence is scant. Using coalescent methods, we analysed past population dynamics of three lizard species (Psammodromus hispanicus, P. edwardsianus, P. occidentalis) and linked the results with climate change data covering the same temporal horizon (120 000 years). An increase in population size over time was observed in two species, and in P. occidentalis, no change was observed. Temporal changes in temperature seasonality and the maximum temperature of the warmest month were congruent with changes in population dynamics observed for the three species and both variables affected population density, either directly or indirectly (via a life-history trait). These results constitute the first solid link between ecological change and long-term population dynamics. The results moreover suggest that ecological change leaves genetic signatures that can be retrospectively traced, providing evidence that ecological change is a crucial driver of genetic diversity and speciation.