14 research outputs found

    Markedly Divergent Tree Assemblage Responses to Tropical Forest Loss and Fragmentation across a Strong Seasonality Gradient

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    We examine the effects of forest fragmentation on the structure and composition of tree assemblages within three seasonal and aseasonal forest types of southern Brazil, including evergreen, Araucaria, and deciduous forests. We sampled three southernmost Atlantic Forest landscapes, including the largest continuous forest protected areas within each forest type. Tree assemblages in each forest type were sampled within 10 plots of 0.1 ha in both continuous forests and 10 adjacent forest fragments. All trees within each plot were assigned to trait categories describing their regeneration strategy, vertical stratification, seed-dispersal mode, seed size, and wood density. We detected differences among both forest types and landscape contexts in terms of overall tree species richness, and the density and species richness of different functional groups in terms of regeneration strategy, seed dispersal mode and woody density. Overall, evergreen forest fragments exhibited the largest deviations from continuous forest plots in assemblage structure. Evergreen, Araucaria and deciduous forests diverge in the functional composition of tree floras, particularly in relation to regeneration strategy and stress tolerance. By supporting a more diversified light-demanding and stress-tolerant flora with reduced richness and abundance of shade-tolerant, old-growth species, both deciduous and Araucaria forest tree assemblages are more intrinsically resilient to contemporary human-disturbances, including fragmentation-induced edge effects, in terms of species erosion and functional shifts. We suggest that these intrinsic differences in the direction and magnitude of responses to changes in landscape structure between forest types should guide a wide range of conservation strategies in restoring fragmented tropical forest landscapes worldwide

    Expression and Function of Ccbe1 in the Chick Early Cardiogenic Regions Are Required for Correct Heart Development

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    During the course of a differential screen to identify transcripts specific for chick heart/hemangioblast precursor cells, we have identified Ccbe1 (Collagen and calcium-binding EGF-like domain 1). While the importance of Ccbe1 for the development of the lymphatic system is now well demonstrated, its role in cardiac formation remained unknown. Here we show by whole-mount in situ hybridization analysis that cCcbe1 mRNA is initially detected in early cardiac progenitors of the two bilateral cardiogenic fields (HH4), and at later stages on the second heart field (HH9-18). Furthermore, cCcbe1 is expressed in multipotent and highly proliferative cardiac progenitors. We characterized the role of cCcbe1 during early cardiogenesis by performing functional studies. Upon morpholino-induced cCcbe1 knockdown, the chick embryos displayed heart malformations, which include aberrant fusion of the heart fields, leading to incomplete terminal differentiation of the cardiomyocytes. cCcbe1 overexpression also resulted in severe heart defects, including cardia bifida. Altogether, our data demonstrate that although cardiac progenitors cells are specified in cCcbe1 morphants, the migration and proliferation of cardiac precursors cells are impaired, suggesting that cCcbe1 is a key gene during early heart development.FCT [SFRH/BD/65628/2009, SFRH/BPD/86497/2012, SFRH/BPD/41081/2007]; F.C.T.B.I. fellowship [PTDC/SAU-BID/114902/ 2009]; FCT; Institute for Biotechnology Bioengineering (Centro Biomedicina Molecular e Celular (IBB/CBME), Laboratorio Associado (LA) in the frame of Project [PestOE/EQB/LA0023/2013]info:eu-repo/semantics/publishedVersio

    The Airway Microbiota in Cystic Fibrosis: A Complex Fungal and Bacterial Community—Implications for Therapeutic Management

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    International audienceBackground Given the polymicrobial nature of pulmonary infections in patients with cystic fibrosis (CF), it is essential to enhance our knowledge on the composition of the microbial community to improve patient management. In this study, we developed a pyrosequencing approach to extensively explore the diversity and dynamics of fungal and prokaryotic populations in CF lower airways. Methodology and Principal Findings Fungi and bacteria diversity in eight sputum samples collected from four adult CF patients was investigated using conventional microbiological culturing and high-throughput pyrosequencing approach targeting the ITS2 locus and the 16S rDNA gene. The unveiled microbial community structure was compared to the clinical profile of the CF patients. Pyrosequencing confirmed recently reported bacterial diversity and observed complex fungal communities, in which more than 60% of the species or genera were not detected by cultures. Strikingly, the diversity and species richness of fungal and bacterial communities was significantly lower in patients with decreased lung function and poor clinical status. Values of Chao1 richness estimator were statistically correlated with values of the Shwachman-Kulczycki score, body mass index, forced vital capacity, and forced expiratory volume in 1 s (p = 0.046, 0.047, 0.004, and 0.001, respectively for fungal Chao1 indices, and p = 0.010, 0.047, 0.002, and 0.0003, respectively for bacterial Chao1 values). Phylogenetic analysis showed high molecular diversities at the sub-species level for the main fungal and bacterial taxa identified in the present study. Anaerobes were isolated with Pseudomonas aeruginosa, which was more likely to be observed in association with Candida albicans than with Aspergillus fumigatus

    Dialelo entre linhagens de uma população de pepino do tipo 'Caipira' Diallel among lines of a 'Caipira' type cucumber population

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    Este trabalho foi realizado para avaliar as capacidades geral e específica de combinação de seis linhagens de pepino 'Caipira', hibridizadas em um esquema dialélico, totalizando 15 híbridos experimentais (H-1 a H-15) possíveis (sem recíprocos). O delineamento foi em blocos ao acaso, com 23 tratamentos (6 linhagens, 15 híbridos experimentais e dois híbridos comerciais: 'Guarani' e 'Safira'), quatro repetições e 5 plantas por parcela. Foram avaliadas as seguintes características: número e massa total de frutos por planta, número e massa de frutos comerciais por planta e taxa de frutos comerciais. O híbrido 'H-5' foi o que apresentou as maiores heteroses para produção de frutos (45 a 51%), com produção comercial (em número de frutos por planta) superior a cinco linhagens e ao híbrido comercial 'Safira'. Tanto os efeitos aditivos como os não aditivos foram significativos para as características de produção de frutos (número e massa por planta), resultando em elevadas capacidades específicas de combinação para a maioria das combinações entre as linhagens. Das 75 estimativas de heterose obtidas, apenas três foram negativas.<br>The objective of this work was to evaluate general and specific combining ability of six 'Caipira' cucumber lines, hybridized in a diallel cross, totalizing 15 experimental hybrids (H-1 to H-15), without reciprocals. The experimental design was randomized blocks with 23 treatments (6 lines, 15 experimental hybrids and two commercial hybrids: 'Safira' and 'Guarani'), four replicates and 5 plants per plot. The following characteristics were evaluated: total fruit number and weight per plant, commercial fruit number and weight per plant and rate of commercial fruits. Hybrid H-5 showed the highest heterosis for fruit yield (45 to 51%), and had commercial yield (fruit number per plant) superior to five lines and to 'Safira' hybrid. Additive and non additive effects were significant for fruit yield (number and weight) per plant, resulting in high specific combining ability for most of lines combinations. From the 75 heterosis estimates, only three were negative
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