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Papers by Emilio menendez fernandez
Deep-sea Research Part Ii-topical Studies in Oceanography, 2006
Recent experimental data from the subtropical NE Atlantic appear to support the prevalence of net... more Recent experimental data from the subtropical NE Atlantic appear to support the prevalence of net heterotrophy in unproductive pelagic ecosystems. However, the proximity of these studies to the NW African upwelling does not exclude the possibility that remote areas of the oceanic gyres are in metabolic balance. Here we present measurements of plankton gross photosynthesis (GPP) and community respiration (CR)
British journal of cancer, Jan 2, 2001
Several studies have suggested an inverse association between use of combined oral contraceptives... more Several studies have suggested an inverse association between use of combined oral contraceptives (OC) and the risk of colorectal cancer and here we present a meta-analysis of published studies. Articles considered were epidemiological studies published as full papers in English up to June 2000 that included quantitative information on OC use. The pooled relative risks (RR) of colorectal cancer for ever OC use from the 8 case-control studies was 0.81 (95% confidence interval (CI): 0.69-0.94), and the pooled estimate from the 4 cohort studies was 0.84 (95% CI: 0.72-0.97). The pooled estimate from all studies combined was 0.82 (95% CI: 0.74-0.92), without apparent heterogeneity. Duration of use was not associated with a decrease in risk, but there was some indication that the apparent protection was stronger for women who had used OCs more recently (RR = 0.46; 95% CI: 0.30-0.71). A better understanding of this potential relation may help informed choice of contraception.
International journal of systematic bacteriology, 1998
Four strains of a hitherto-unknown catalase-positive, facultatively anaerobic Corynebacterium spe... more Four strains of a hitherto-unknown catalase-positive, facultatively anaerobic Corynebacterium species were isolated from the milk of sheep affected by subclinical mastitis. The most characteristic phenotypic reactions of the four strains were their weak fermentative acid production from glucose, their failure to produce acid from mannitol, xylose, sucrose and maltose, and a strong CAMP reaction with Staphylococcus aureus. Chemotaxonomic investigations revealed the presence of a cell wall based on meso-diaminopimelic acid and short-chain mycolic acids, which is consistent with the genus Corynebacterium. A comparative 16S rRNA gene sequence analysis confirmed that the organisms from sheep were members of the genus Corynebacterium, where they formed a distinct subline, exhibiting > 4% sequence divergence with other known Corynebacterium species. Based on both phenotypic and phylogenetic findings, a new species, Corynebacterium camporealensis, is proposed. The type strain of Coryneba...
Plant molecular biology, 1997
A family of high-affinity nitrate transporters has been identified in Aspergillus nidulans and Ch... more A family of high-affinity nitrate transporters has been identified in Aspergillus nidulans and Chlamydomonas reinhardtii, and recently homologues of this family have been cloned from a higher plant (barley). Based on six of the peptide sequences most strongly conserved between the barley and C. reinhardtii polypeptides, a set of degenerate primers was designed to permit amplification of the corresponding genes from other plant species. The utility of these primers was demonstrated by RT-PCR with cDNA made from poly(A)+ RNA from barley, C. reinhardtii and Nicotiana plumbaginifolia. A PCR fragment amplified from N. plumbaginifolia was used as probe to isolate a full-length cDNA clone which encodes a protein, NRT2;1Np, that is closely related to the previously isolated crnA homologue from barley. Genomic Southern blots indicated that there are only 1 or 2 members of the Nrt2 gene family in N. plumbaginifolia. Northern blotting showed that the Nrt2 transcripts are most strongly expresse...
Pre-filtration of water samples for elimination of zooplankton and phytoplankton causes overestim... more Pre-filtration of water samples for elimination of zooplankton and phytoplankton causes overestimation of the bacterial contribution to community respiration in oligotrophic pelagic systems.
ABSTRACT We surveyed the oligotrophic waters of the north-eastern Atlantic subtropical gyre to in... more ABSTRACT We surveyed the oligotrophic waters of the north-eastern Atlantic subtropical gyre to investigate the biomass, abundance, composition and variability of the protistan microzooplankton community. Aloricate ciliates and gymnodinoid dinoflagellates dominated the community, which did not show broad seasonal variations. Large mixotrophic ciliates, with a high carbon content per cell, accounted for a substantial amount of the variability of the standing stock. We found average values of microzooplankton biomass and abundance of 1.1 mg C m−3 and 3.7 × 103 cells l−l, respectively, which are among the lowest measured in marine systems, 5- to 10-fold lower than in the neighbouring waters of the North Atlantic Drift. The mesoscale structures surveyed, a cyclonic eddy and the hydrographical structures over a submarine mount, significantly enhanced microzooplankton biomass and sustained the presence of cells with a carbon content higher than in neighbouring waters. Microzooplankton followed complex patterns of distribution that did not correspond to the variability of primary production or of chlorophyll a.
The distribution, abundance and composition of suspended particulates, phytoplankton and zooplank... more The distribution, abundance and composition of suspended particulates, phytoplankton and zooplankton biomass were investigated for the marginal ice zone in the Bellingshausen Sea during the Austral spring of 1992. Marked changes were observed between the amount and composition of particulates under the sea-ice and those in open waters. Measures of phytoplankton abundance (chlorophyll) ranged from ∼0.05 μg l−1 under the
Deep-sea Research Part Ii-topical Studies in Oceanography, 2006
Recent experimental data from the subtropical NE Atlantic appear to support the prevalence of net... more Recent experimental data from the subtropical NE Atlantic appear to support the prevalence of net heterotrophy in unproductive pelagic ecosystems. However, the proximity of these studies to the NW African upwelling does not exclude the possibility that remote areas of the oceanic gyres are in metabolic balance. Here we present measurements of plankton gross photosynthesis (GPP) and community respiration (CR)
British journal of cancer, Jan 2, 2001
Several studies have suggested an inverse association between use of combined oral contraceptives... more Several studies have suggested an inverse association between use of combined oral contraceptives (OC) and the risk of colorectal cancer and here we present a meta-analysis of published studies. Articles considered were epidemiological studies published as full papers in English up to June 2000 that included quantitative information on OC use. The pooled relative risks (RR) of colorectal cancer for ever OC use from the 8 case-control studies was 0.81 (95% confidence interval (CI): 0.69-0.94), and the pooled estimate from the 4 cohort studies was 0.84 (95% CI: 0.72-0.97). The pooled estimate from all studies combined was 0.82 (95% CI: 0.74-0.92), without apparent heterogeneity. Duration of use was not associated with a decrease in risk, but there was some indication that the apparent protection was stronger for women who had used OCs more recently (RR = 0.46; 95% CI: 0.30-0.71). A better understanding of this potential relation may help informed choice of contraception.
International journal of systematic bacteriology, 1998
Four strains of a hitherto-unknown catalase-positive, facultatively anaerobic Corynebacterium spe... more Four strains of a hitherto-unknown catalase-positive, facultatively anaerobic Corynebacterium species were isolated from the milk of sheep affected by subclinical mastitis. The most characteristic phenotypic reactions of the four strains were their weak fermentative acid production from glucose, their failure to produce acid from mannitol, xylose, sucrose and maltose, and a strong CAMP reaction with Staphylococcus aureus. Chemotaxonomic investigations revealed the presence of a cell wall based on meso-diaminopimelic acid and short-chain mycolic acids, which is consistent with the genus Corynebacterium. A comparative 16S rRNA gene sequence analysis confirmed that the organisms from sheep were members of the genus Corynebacterium, where they formed a distinct subline, exhibiting > 4% sequence divergence with other known Corynebacterium species. Based on both phenotypic and phylogenetic findings, a new species, Corynebacterium camporealensis, is proposed. The type strain of Coryneba...
Plant molecular biology, 1997
A family of high-affinity nitrate transporters has been identified in Aspergillus nidulans and Ch... more A family of high-affinity nitrate transporters has been identified in Aspergillus nidulans and Chlamydomonas reinhardtii, and recently homologues of this family have been cloned from a higher plant (barley). Based on six of the peptide sequences most strongly conserved between the barley and C. reinhardtii polypeptides, a set of degenerate primers was designed to permit amplification of the corresponding genes from other plant species. The utility of these primers was demonstrated by RT-PCR with cDNA made from poly(A)+ RNA from barley, C. reinhardtii and Nicotiana plumbaginifolia. A PCR fragment amplified from N. plumbaginifolia was used as probe to isolate a full-length cDNA clone which encodes a protein, NRT2;1Np, that is closely related to the previously isolated crnA homologue from barley. Genomic Southern blots indicated that there are only 1 or 2 members of the Nrt2 gene family in N. plumbaginifolia. Northern blotting showed that the Nrt2 transcripts are most strongly expresse...
Pre-filtration of water samples for elimination of zooplankton and phytoplankton causes overestim... more Pre-filtration of water samples for elimination of zooplankton and phytoplankton causes overestimation of the bacterial contribution to community respiration in oligotrophic pelagic systems.
ABSTRACT We surveyed the oligotrophic waters of the north-eastern Atlantic subtropical gyre to in... more ABSTRACT We surveyed the oligotrophic waters of the north-eastern Atlantic subtropical gyre to investigate the biomass, abundance, composition and variability of the protistan microzooplankton community. Aloricate ciliates and gymnodinoid dinoflagellates dominated the community, which did not show broad seasonal variations. Large mixotrophic ciliates, with a high carbon content per cell, accounted for a substantial amount of the variability of the standing stock. We found average values of microzooplankton biomass and abundance of 1.1 mg C m−3 and 3.7 × 103 cells l−l, respectively, which are among the lowest measured in marine systems, 5- to 10-fold lower than in the neighbouring waters of the North Atlantic Drift. The mesoscale structures surveyed, a cyclonic eddy and the hydrographical structures over a submarine mount, significantly enhanced microzooplankton biomass and sustained the presence of cells with a carbon content higher than in neighbouring waters. Microzooplankton followed complex patterns of distribution that did not correspond to the variability of primary production or of chlorophyll a.
The distribution, abundance and composition of suspended particulates, phytoplankton and zooplank... more The distribution, abundance and composition of suspended particulates, phytoplankton and zooplankton biomass were investigated for the marginal ice zone in the Bellingshausen Sea during the Austral spring of 1992. Marked changes were observed between the amount and composition of particulates under the sea-ice and those in open waters. Measures of phytoplankton abundance (chlorophyll) ranged from ∼0.05 μg l−1 under the