Suchergebnisse

11 páginas, 4 figuras, 6 tablas. ; Prenatal levels of organohalogen compounds (OHCs), including polybromodiphenyl ethers (PBDEs), polychlorobiphenyls (PCBs), hexachlorobenzene (HCB), hexachlorocyclohexanes and DDTs have been investigated in two different cohorts from the Spanish Mediterranean area, Valencia and Menorca, by analysis of cord blood serum. Comparison of the observed median concentrations to other cohorts show low PBDE levels (2.8-6.8 ng/g lipid) but high values of HCB (0.68 ng/ml, 260 ng/g lipid) and PCBs (0.65 ng/ml, 240 ng/g lipid) in the cohort of Menorca indicating that Mediterranean areas, and not only high latitude regions, may contain population groups highly exposed to some of these pollutants. Significant differences in the concentrations of these compounds have been found between the two cohorts. Differences in maternal population such as age or body mass index cannot explain this variation. One possible cause of variability is the seven year time period elapsed between the two cohort recruitments but the strong differences observed do not allow exclusion of local diet differences. Thus, the different average PCB congener distributions between the two cohorts suggests an influence from materials containing diverse PCB mixtures. The congener mixtures found in Menorca could reflect a diet contribution from some western Mediterranean fish species. These results provide baseline information on prenatal OHC background levels in the Mediterranean area. ; The authors are grateful to the mothers who participated in the study and to Hospital La Fe. Funding was received from the Spanish Ministry of Health and Ministry of Science and Innovation (INMA G03/176, Consolider Ingenio GRACCIE, CSD2007-00067, FIS-FEDER: 03/1615, 04/1112, 04/1509, 04/1666, 05/1987, 06/1213 and 09/2647), Council of Health from the Autonomous Valencian Government (Generalitat Valenciana), Fundacio Roger Torne and ArcRisk EU Project (FP7-ENV-2008-1-226534). ; Peer reviewed

© María Ángeles Lezcano et al. 2019. ; Substrate–atmosphere interfaces in Antarctic geothermal environments are hot–cold regions that constitute thin habitable niches for microorganisms with possible counterparts in ancient Mars. Cerro Caliente hill in Deception Island (active volcano in the South Shetland Islands) is affected by ascending hydrothermal fluids that form a band of warm substrates buffered by low air temperatures. We investigated the influence of temperature on the community structure and metabolism of three microbial mats collected along the geothermal band of Cerro Caliente registering 88°C, 8°C, and 2°C at the time of collection. High-throughput sequencing of small subunit ribosomal ribonucleic acid (SSU rRNA) genes and Life Detector Chip (LDChip) microarray immunoassays revealed different bacterial, archaeal, and eukaryotic composition in the three mats. The mat at 88°C showed the less diverse microbial community and a higher proportion of thermophiles (e.g., Thermales). In contrast, microbial communities in the mats at 2°C and 8°C showed relatively higher diversity and higher proportion of psychrophiles (e.g., Flavobacteriales). Despite this overall association, similar microbial structures at the phylum level (particularly the presence of Cyanobacteria) and certain hot- and cold-tolerant microorganisms were identified in the three mats. Daily thermal oscillations recorded in the substrate over the year (4.5–76°C) may explain the coexistence of microbial fingerprints with different thermal tolerances. Stable isotope composition also revealed metabolic differences among the microbial mats. Carbon isotopic ratios suggested the Calvin–Benson–Bassham cycle as the major pathway for carbon dioxide fixation in the mats at 2°C and 8°C, and the reductive tricarboxylic acid cycle and/or the 3-hydroxypropionate bicycle for the mat at 88°C, indicating different metabolisms as a function of the prevailing temperature of each mat. The comprehensive biomarker profile on the three microbial mats from Cerro Caliente contributes to unravel the diversity, composition, and metabolism in geothermal polar sites and highlights the relevance of geothermal-cold environments to create habitable niches with interest in other planetary environments. ; This study has been funded by the Spanish Research Agency (AEI) from the Ministry of Science Innovation and Universities and the European FEDER Grants Nos. ESP2015-69540-R, RYC2014-19446, and CGL2015-74254-JIN; the AEI Project No. MDM-2017-0737 Unidad de Excelencia ''Marı´a de Maeztu,'' and the European Research Council Starting Grant (ERC StG) No. 307496. M.A´ . Lezcano and M.A´ . Fernández Martínez were supported by a postdoctoral fellowship by the Youth Employment Initiative from the European Union and implanted in Comunidad de Madrid.