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  • Open Access English
    Authors: 
    Bettencourt, R.; Rodrigues, M. I.; Barros, I.; Cerqueira, T.; Freitas, C.; Costa, V.; Pinheiro, M.; Egas, C.; Santos, R. S.;
    Project: FCT | PTDC/MAR/65991/2006 (PTDC/MAR/65991/2006), EC | HERMIONE (226354), FCT | PEst-OE/EEI/LA0009/2011 (PEst-OE/EEI/LA0009/2011)

    The deep-sea hydrothermal vent mussel Bathymodiolus azoricus is a symbiont bearing bivalve that is found in great abundance at the Menez Gwen and Lucky Strike vent sites and in close vicinity off the Azores region near the Mid-Atlantic Ridge (MAR). The distinct relationships that vent mussels have developed with their physical and chemical environments are likely reflected in global gene expression profiles providing thus a means to distinguish geographically distinct vent mussels on the basis of gene expression studies, fluorescence in situ hybridization (FISH) experiments and 16S rRNA amplicon sequencing, to assess the natural expression of bacterial genes and vent mussel immune genes and the constitutive distribution and relative abundance of endosymbiotic bacteria within gill tissues. Our results confirmed the presence of methanotroph-related endosymbionts in Menez Gwen vent mussels whereas Lucky Strike specimens seem to harbor a different bacterial morphotype when a methane monooxygenase gene specific probe was used. No qualitative differences could be visualized between Menez Gwen and Lucky Strike individuals when tested with sulfur-oxidizing-related nucleic-acid probe. Quantitative PCR (qPCR) studies revealed varied gene expression profiles in both Menez Gwen and Lucky Strike mussel gill tissues for the immune genes selected. Genes encoding transcription factors presented noticeably low levels of fold expression whether in MG or LS animals whereas the genes encoding effector molecules appeared to have higher levels expression in MG gill tissues. The peptidoglycan recognition molecule, encoding gene, PGRP presented the highest level of transcriptional activity among the genes analyzed in MG gill tissues, seconded by carcinolectin and thus denoting the relevance of immune recognition molecules in early stage of the immune responses onset. Genes regarded as encoding molecules involved in signaling pathways were consistently expressed in both MG and LS gill tissues. Remarkably, the immunity-related GTPase encoding gene demonstrated in LS samples, the highest level of expression among the signaling molecule encoding genes tested when expressions levels were compared between MG and LG animals. A differential expression analysis of bacterial genes between MG and LS indicated a clear expression signature in LS gill tissues. The bacterial community structure ensued from the 16S rRNA sequencing analyses pointed at a unpredicted conservation of endosymbiont bacterial loads between MG and LS samples. Taken together, our results support the premise that Bathymodiolus azoricus exhibits different transcriptional statuses depending on which hydrothermal vent site it is collected from and within the same collection site while exhibiting differential levels of expression of genes corresponding to different immune functional categories. The present study represents a first attempt to characterize gene expression signatures in hydrothermal vent animals issued from distinct deep-sea environmental sites based on immune and bacterial genes expressions.

  • Open Access
    Authors: 
    Diana Zúñiga; Célia Santos; M. Froján; Emilia Salgueiro; Marta M Rufino; Francisco de la Granda; Francisco G. Figueiras; Carmen G. Castro; Fatima F Abrantes;
    Publisher: European Geosciences Union
    Countries: Spain, France, Portugal
    Project: FCT | SFRH/BD/88439/2012 (SFRH/BD/88439/2012), FCT | PTDC/MAR/102045/2008 (PTDC/MAR/102045/2008), FCT | SFRH/BPD/111433/2015 (SFRH/BPD/111433/2015)

    The objective of the current work is to improve our understanding of how water column diatom’s abundance and assemblage composition is seasonally transferred from the photic zone to seafloor sediments. To address this, we used a dataset derived from water column, sediment trap and surface sediment samples recovered in the NW Iberian coastal upwelling system. Diatom fluxes (2.2 ( +-5.6) 106 valves m-2 d-1/ represented the majority of the siliceous microorganisms sinking out from the photic zone during all studied years and showed seasonal variability. Contrasting results between water column and sediment trap diatom abundances were found during downwelling periods, as shown by the unexpectedly high diatom export signals when diatom-derived primary production achieved their minimum levels. They were principally related to surface sediment remobilization and intense Minho and Douro river discharge that constitute an additional source of particulate matter to the inner continental shelf. In fact, contributions of allochthonous particles to the sinking material were confirmed by the significant increase of both benthic and freshwater diatoms in the sediment trap assemblage. In contrast, we found that most of the living diatom species blooming during highly productive upwelling periods were dissolved during sinking, and only those resistant to dissolution and the Chaetoceros and Leptocylindrus spp. resting spores were susceptible to being exported and buried. Furthermore, Chaetoceros spp. dominate during spring–early summer, when persistent northerly winds lead to the upwelling of nutrient-rich waters on the shelf, while Leptocylindrus spp. appear associated with late-summer upwelling relaxation, characterized by water column stratification and nutrient depletion. These findings evidence that the contributions of these diatom genera to the sediment’s total marine diatom assemblage should allow for the reconstruction of different past upwelling regimes This study was sponsored by CAIBEX (CTM2007-66408-C02-01/MAR) and REIMAGE (CTM2011-30155-C03-03) projects funded by the Spanish Government, EXCAPA project (10MDS402013PR) supported by Xunta de Galicia, the EU FEDER funded projects RAIA (INTERREG 2009/2011-0313/RAIA/E) and RAIA.co (INTERREG 2011/2013-052/RAIA.co/1E) and the CALIBERIA project (PTDC/MAR/102045/2008) financed by Fundação para a Ciência e a Tecnologia (FCT-Portugal) and COMPETE/FEDER -FCOMP- 01-0124-FEDER-010599. Diana Zúñiga and Emilia Salgueiro were funded by a postdoctoral fellowship (Plan I2C) from Xunta de Galicia (Spain) and (SFRH/BPD/111433/2015) from FCT, respectively. Celia Santos was funded by a doctoral grant from FCT (Portugal) (SFRH/BD/88439/2012) 15 páginas, 1 apéndice, 8 figuras, 3 tablas.-- This work is distributed under the Creative Commons Attribution 3.0 License Peer reviewed

Advanced search in Research products
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Include:
The following results are related to European Marine Science. Are you interested to view more results? Visit OpenAIRE - Explore.
2 Research products, page 1 of 1
  • Open Access English
    Authors: 
    Bettencourt, R.; Rodrigues, M. I.; Barros, I.; Cerqueira, T.; Freitas, C.; Costa, V.; Pinheiro, M.; Egas, C.; Santos, R. S.;
    Project: FCT | PTDC/MAR/65991/2006 (PTDC/MAR/65991/2006), EC | HERMIONE (226354), FCT | PEst-OE/EEI/LA0009/2011 (PEst-OE/EEI/LA0009/2011)

    The deep-sea hydrothermal vent mussel Bathymodiolus azoricus is a symbiont bearing bivalve that is found in great abundance at the Menez Gwen and Lucky Strike vent sites and in close vicinity off the Azores region near the Mid-Atlantic Ridge (MAR). The distinct relationships that vent mussels have developed with their physical and chemical environments are likely reflected in global gene expression profiles providing thus a means to distinguish geographically distinct vent mussels on the basis of gene expression studies, fluorescence in situ hybridization (FISH) experiments and 16S rRNA amplicon sequencing, to assess the natural expression of bacterial genes and vent mussel immune genes and the constitutive distribution and relative abundance of endosymbiotic bacteria within gill tissues. Our results confirmed the presence of methanotroph-related endosymbionts in Menez Gwen vent mussels whereas Lucky Strike specimens seem to harbor a different bacterial morphotype when a methane monooxygenase gene specific probe was used. No qualitative differences could be visualized between Menez Gwen and Lucky Strike individuals when tested with sulfur-oxidizing-related nucleic-acid probe. Quantitative PCR (qPCR) studies revealed varied gene expression profiles in both Menez Gwen and Lucky Strike mussel gill tissues for the immune genes selected. Genes encoding transcription factors presented noticeably low levels of fold expression whether in MG or LS animals whereas the genes encoding effector molecules appeared to have higher levels expression in MG gill tissues. The peptidoglycan recognition molecule, encoding gene, PGRP presented the highest level of transcriptional activity among the genes analyzed in MG gill tissues, seconded by carcinolectin and thus denoting the relevance of immune recognition molecules in early stage of the immune responses onset. Genes regarded as encoding molecules involved in signaling pathways were consistently expressed in both MG and LS gill tissues. Remarkably, the immunity-related GTPase encoding gene demonstrated in LS samples, the highest level of expression among the signaling molecule encoding genes tested when expressions levels were compared between MG and LG animals. A differential expression analysis of bacterial genes between MG and LS indicated a clear expression signature in LS gill tissues. The bacterial community structure ensued from the 16S rRNA sequencing analyses pointed at a unpredicted conservation of endosymbiont bacterial loads between MG and LS samples. Taken together, our results support the premise that Bathymodiolus azoricus exhibits different transcriptional statuses depending on which hydrothermal vent site it is collected from and within the same collection site while exhibiting differential levels of expression of genes corresponding to different immune functional categories. The present study represents a first attempt to characterize gene expression signatures in hydrothermal vent animals issued from distinct deep-sea environmental sites based on immune and bacterial genes expressions.

  • Open Access
    Authors: 
    Diana Zúñiga; Célia Santos; M. Froján; Emilia Salgueiro; Marta M Rufino; Francisco de la Granda; Francisco G. Figueiras; Carmen G. Castro; Fatima F Abrantes;
    Publisher: European Geosciences Union
    Countries: Spain, France, Portugal
    Project: FCT | SFRH/BD/88439/2012 (SFRH/BD/88439/2012), FCT | PTDC/MAR/102045/2008 (PTDC/MAR/102045/2008), FCT | SFRH/BPD/111433/2015 (SFRH/BPD/111433/2015)

    The objective of the current work is to improve our understanding of how water column diatom’s abundance and assemblage composition is seasonally transferred from the photic zone to seafloor sediments. To address this, we used a dataset derived from water column, sediment trap and surface sediment samples recovered in the NW Iberian coastal upwelling system. Diatom fluxes (2.2 ( +-5.6) 106 valves m-2 d-1/ represented the majority of the siliceous microorganisms sinking out from the photic zone during all studied years and showed seasonal variability. Contrasting results between water column and sediment trap diatom abundances were found during downwelling periods, as shown by the unexpectedly high diatom export signals when diatom-derived primary production achieved their minimum levels. They were principally related to surface sediment remobilization and intense Minho and Douro river discharge that constitute an additional source of particulate matter to the inner continental shelf. In fact, contributions of allochthonous particles to the sinking material were confirmed by the significant increase of both benthic and freshwater diatoms in the sediment trap assemblage. In contrast, we found that most of the living diatom species blooming during highly productive upwelling periods were dissolved during sinking, and only those resistant to dissolution and the Chaetoceros and Leptocylindrus spp. resting spores were susceptible to being exported and buried. Furthermore, Chaetoceros spp. dominate during spring–early summer, when persistent northerly winds lead to the upwelling of nutrient-rich waters on the shelf, while Leptocylindrus spp. appear associated with late-summer upwelling relaxation, characterized by water column stratification and nutrient depletion. These findings evidence that the contributions of these diatom genera to the sediment’s total marine diatom assemblage should allow for the reconstruction of different past upwelling regimes This study was sponsored by CAIBEX (CTM2007-66408-C02-01/MAR) and REIMAGE (CTM2011-30155-C03-03) projects funded by the Spanish Government, EXCAPA project (10MDS402013PR) supported by Xunta de Galicia, the EU FEDER funded projects RAIA (INTERREG 2009/2011-0313/RAIA/E) and RAIA.co (INTERREG 2011/2013-052/RAIA.co/1E) and the CALIBERIA project (PTDC/MAR/102045/2008) financed by Fundação para a Ciência e a Tecnologia (FCT-Portugal) and COMPETE/FEDER -FCOMP- 01-0124-FEDER-010599. Diana Zúñiga and Emilia Salgueiro were funded by a postdoctoral fellowship (Plan I2C) from Xunta de Galicia (Spain) and (SFRH/BPD/111433/2015) from FCT, respectively. Celia Santos was funded by a doctoral grant from FCT (Portugal) (SFRH/BD/88439/2012) 15 páginas, 1 apéndice, 8 figuras, 3 tablas.-- This work is distributed under the Creative Commons Attribution 3.0 License Peer reviewed