53 research outputs found

    Fungal ecological strategies reflected in gene transcription - a case study of two litter decomposers.

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    Microbial communities interplay with their environment through their functional traits that can be a response or an effect on the environment. Here, we explore how a functional trait-the decomposition of organic matter, can be addressed based on genetic markers and how the expression of these markers reflect ecological strategies of two fungal litter decomposer Gymnopus androsaceus and Chalara longipes. We sequenced the genomes of these two fungi, as well as their transcriptomes at different steps of Pinus sylvestris needles decomposition in microcosms. Our results highlighted that if the gene content of the two species could indicate similar potential decomposition abilities, the expression levels of specific gene families belonging to the glycoside hydrolase category reflected contrasting ecological strategies. Actually, C. longipes, the weaker decomposer in this experiment, turned out to have a high content of genes involved in cell wall polysaccharides decomposition but low expression levels, reflecting a versatile ecology compare to the more competitive G. androsaceus with high expression levels of keystone functional genes. Thus, we established that sequential expression of genes coding for different components of the decomposer machinery indicated adaptation to chemical changes in the substrate as decomposition progressed

    Stranding of larval nase (Chondrostoma nasus L.) depending on bank slope, down-ramping rate and daytime

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    Rapid water level decreases due to hydropeaking are known to negatively affect riverine biota, mainly due to the stranding of organisms in the river bank area that becomes regularly dewatered. Even though studies of the last decades have focused on salmonid fish, also cyprinids may be affected. However, limited knowledge is available of this fish family. Therefore, we conducted mesocosm experiments under semi-natural conditions, simulating single hydropeaking events at two different lateral bank slopes (2% and 5%) with varying down-ramping rates (0.7–3.0 cm min−1) during day and night. As a response parameter, we quantified stranding rates of different larval stages (III-IV and V) of common nase (Chondrostoma nasus L.). The experiments revealed that lower sloped banks exhibited distinctly higher stranding rates than steeper ones. Daytime revealed a similar pattern, with more fish becoming stranded at night than during the day, and this was consistent for all down-ramping rates. The data also indicate increased stranding with higher down-ramping rates, particularly at low sloped riverbanks, and interaction effects between the tested parameters. Overall, this study, for the first time, quantifies the consequences of flow down-ramping on nase larvae, also revealing differences between larval stages. The gained information will, therefore, advance the ongoing discussion on hydropeaking mitigation by providing a deeper understanding of the effects of artificial sub-daily flow fluctuations on the early life stages of cyprinid fish. Our results can inform management and policy to sharpen existing mitigation concepts and fine-tune hydropower operations to reduce negative effects on riverine ecosystems

    O poder e a luta pela propriedade da terra no vale do rio Iconha/Piúma: o caso Thomaz Dutton Junior (1870-1906)

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    Ao chegar ao povoado de Piúma, região sul capixaba, por volta dos anos iniciais da década de 1870, Thomaz Dutton Junior, inglês de nascimento e mais tarde naturalizado brasileiro, desejava fazer parte da boa sociedade e ter direito a todas as prerrogativas que o grupo proporcionaria. No território de Piúma, adquiriu boa parte da massa falida de João Baptista Rodocanachi, um comerciante grego de grosso trato que explorava madeiras de lei e as comercializava para construção civil e naval. Na fazenda Monte Bello, após instalar colonos ingleses, Thomaz Dutton se envolveu em querelas jurídico-fundiárias com mandões do lugar com quem tinha relações interdependentes, sobretudo com Alexandrino Pires Martins e José Gonçalves Costa Beiriz, que ocultavam, ao fim e ao cabo, um complexo jogo por disputas políticas locais, por prestígio, por boa reputação e poder. No seio dessas disputas estava a propriedade da terra, símbolo de poder e mando, que o levou à insolvência. Este estudo investiga a trajetória de Thomaz Dutton, pautando-se na teoria da Configuração de Norbert Elias associada à teoria do Poder Simbólico de Pierre Bourdier. Objetiva compreender a maneira como as práticas do poder são materializadas nas relações sociais, identificando a aprendizagem extraída de relações interdependentes bem como os valores construídos a partir delas. Parte de análises de fontes documentais, como relatórios presidenciais provinciais, requerimentos, atas, cartas e artigos de jornais corpus documental, dominante nesta investigação , buscando vestígios no conteúdo dos discursos ali inseridos para poder descortinar as tramas do tecido social com lentes de objetivas aumentadas. Desse modo, torna possível trazer à tona a história local do território do vale do Iconha/Piúma no espaço de tempo entre 1870 e 1906 e assim expor suas particularidades e singularidades, inserindo-a no contexto da história regional capixaba e nacional. Destarte, usando o alicerce teórico-metodológico já apresentado, destaca as particularidades e feitos do passado da sociedade piumense que ainda estavam fora do campo de experiência e precisavam ser conhecidas para fazer parte da História do Espírito Santo

    Large-scale genome sequencing of mycorrhizal fungi provides insights into the early evolution of symbiotic traits

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    Mycorrhizal fungi are mutualists that play crucial roles in nutrient acquisition in terrestrial ecosystems. Mycorrhizal symbioses arose repeatedly across multiple lineages of Mucoromycotina, Ascomycota, and Basidiomycota. Considerable variation exists in the capacity of mycorrhizal fungi to acquire carbon from soil organic matter. Here, we present a combined analysis of 135 fungal genomes from 73 saprotrophic, endophytic and pathogenic species, and 62 mycorrhizal species, including 29 new mycorrhizal genomes. This study samples ecologically dominant fungal guilds for which there were previously no symbiotic genomes available, including ectomycorrhizal Russulales, Thelephorales and Cantharellales. Our analyses show that transitions from saprotrophy to symbiosis involve (1) widespread losses of degrading enzymes acting on lignin and cellulose, (2) co-option of genes present in saprotrophic ancestors to fulfill new symbiotic functions, (3) diversification of novel, lineage-specific symbiosis-induced genes, (4) proliferation of transposable elements and (5) divergent genetic innovations underlying the convergent origins of the ectomycorrhizal guild. Mycorrhizal symbioses have evolved repeatedly in diverse fungal lineages. A large phylogenomic analysis sheds light on genomic changes associated with transitions from saprotrophy to symbiosis, including divergent genetic innovations underlying the convergent origins of the ectomycorrhizal guild.Peer reviewe

    Autoportrait tirant la langue

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    Épreuve sur papier salé d’après un négatif sur verre au collodion, 12 × 10 cmCoiffés du bonnet polonais, Fauchery, Félix et Adrien Tournachon ont tenté de rejoindre la Légion Polonaise en 1848. Antoine Fauchery faisait partie de la bande de la rue des Canettes avec Murger et Champfleury. Il collaborait au Corsaire-Satan et dans plusieurs petits journaux. « Facile au rêve » comme l’écrit Nadar, il a eu une existence plus inattendue que ses camarades. En 1852, il part pour l’Australie comme chercheur d’or et, de retour à Paris, publie ses Lettres d’un mineur en Australie , préfacées par Théodore de Banville. Il repart, dès 1858, pour l’Australie comme photographe, d’abord à Melbourne, avant s’embarquer pour Manille. Il sera correspondant de guerre pendant l’expédition française en Chine, mais malade, doit rejoindre le Japon où il meurt à Yokohama. C'est en 1858 qu'il envoie ce souvenir amicalement provocateur à son professeur de photographie.téléchargeabl

    Self-portrait with tongue stuck out

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    Salt-paper print from a collodion glass negative, 12 x 10 cm.Wearing Polish caps, Fauchery and Félix and Adrien Tournachon tried to join the Polish Legion in 1848. Along with Murger and Champfleury, Antoine Fauchery was part of the Rue des Canettes group He contributed to the Corsaire-Satan and several other small newspapers. As someone who "succumbed easily to dreams," as Nadar wrote, he had a more surprising existence than his comrades. In 1852, he went to Australia to look for gold. Once back in Paris, he published his Lettres d’un mineur en Australie ( Letters from an Australian Gold Miner) , with a forward by Théodore de Banville. In 1858, he went back to Australia, as a photographer this time, first in Melbourne, before embarking for Manilla. A war correspondent during the French expedition in China, he fell ill and had to leave for Japan, where he died, in Yokohama. In 1858 he had sent this cheerfully provocative souvenir to the man who taught him photography.téléchargeabl

    Hot markets, underpricing and underperformance ::IPO anomalies under the light of modern risk factors

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    This paper investigates to which extent multifactor asset pricing models can explain the pricing of IPOs in the U.S. market between 1980 and 2015. The paper contributes to the existing literature by demonstrating that the hot market, the underpricing and the underperformance issues can be explained by the general trends and the intensities of various risk factors. We analyse the latter based on the expectation that the number of IPOs, the underpricing and the underperformance are higher when the global economy performs well. In the cases of the hot market and the underpricing, the risk factors are correlated consistently to expectations. However, this is not always the case for IPO underperformance for which coefficients differ from expectations. Finally, the risk factors identified as main predictors differ for the three IPO anomalies
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