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31.
Nicola Pirastu Ciara McDonnell Eryk J. Grzeszkowiak Ninon Mounier Fumiaki Imamura Jordi Merino Felix R. Day Jie Zheng Nele Taba Maria Pina Concas Linda Repetto Katherine A. Kentistou Antonietta Robino Tnu Esko Peter K. Joshi Krista Fischer Ken K. Ong Tom R. Gaunt Zoltn Kutalik John R. B. Perry James F. Wilson 《PLoS genetics》2022,18(6)
Diet is considered as one of the most important modifiable factors influencing human health, but efforts to identify foods or dietary patterns associated with health outcomes often suffer from biases, confounding, and reverse causation. Applying Mendelian randomization in this context may provide evidence to strengthen causality in nutrition research. To this end, we first identified 283 genetic markers associated with dietary intake in 445,779 UK Biobank participants. We then converted these associations into direct genetic effects on food exposures by adjusting them for effects mediated via other traits. The SNPs which did not show evidence of mediation were then used for MR, assessing the association between genetically predicted food choices and other risk factors, health outcomes. We show that using all associated SNPs without omitting those which show evidence of mediation, leads to biases in downstream analyses (genetic correlations, causal inference), similar to those present in observational studies. However, MR analyses using SNPs which have only a direct effect on the exposure on food exposures provided unequivocal evidence of causal associations between specific eating patterns and obesity, blood lipid status, and several other risk factors and health outcomes. 相似文献
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33.
Responses of two semiarid conifer tree species to reduced precipitation and warming reveal new perspectives for stomatal regulation
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NúRIA Garcia‐Forner Henry D. Adams Sanna Sevanto Adam D. Collins Lee T. Dickman Patrick J. Hudson Melanie J.B. Zeppel Michael W. Jenkins Heath Powers Jordi Martínez‐Vilalta Nate G. Mcdowell 《Plant, cell & environment》2016,39(1):38-49
Relatively anisohydric species are predicted to be more predisposed to hydraulic failure than relatively isohydric species, as they operate with narrower hydraulic safety margins. We subjected co‐occurring anisohydric Juniperus monosperma and isohydric Pinus edulis trees to warming, reduced precipitation, or both, and measured their gas exchange and hydraulic responses. We found that reductions in stomatal conductance and assimilation by heat and drought were more frequent during relatively moist periods, but these effects were not exacerbated in the combined heat and drought treatment. Counter to expectations, both species exhibited similar gs temporal dynamics in response to drought. Further, whereas P. edulis exhibited chronic embolism, J. monosperma showed very little embolism due to its conservative stomatal regulation and maintenance of xylem water potential above the embolism entry point. This tight stomatal control and low levels of embolism experienced by juniper refuted the notion that very low water potentials during drought are associated with loose stomatal control and with the hypothesis that anisohydric species are more prone to hydraulic failure than isohydric species. Because direct association of stomatal behaviour with embolism resistance can be misleading, we advocate consideration of stomatal behaviour relative to embolism resistance for classifying species drought response strategies. 相似文献
34.
Phosphorus accumulates faster than nitrogen globally in freshwater ecosystems under anthropogenic impacts 总被引:1,自引:0,他引:1
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Zhengbing Yan Wenxuan Han Josep Peñuelas Jordi Sardans James J. Elser Enzai Du Peter B. Reich Jingyun Fang 《Ecology letters》2016,19(10):1237-1246
Combined effects of cumulative nutrient inputs and biogeochemical processes that occur in freshwater under anthropogenic eutrophication could lead to myriad shifts in nitrogen (N):phosphorus (P) stoichiometry in global freshwater ecosystems, but this is not yet well‐assessed. Here we evaluated the characteristics of N and P stoichiometries in bodies of freshwater and their herbaceous macrophytes across human‐impact levels, regions and periods. Freshwater and its macrophytes had higher N and P concentrations and lower N : P ratios in heavily than lightly human‐impacted environments, further evidenced by spatiotemporal comparisons across eutrophication gradients. N and P concentrations in freshwater ecosystems were positively correlated and N : P was negatively correlated with population density in China. These results indicate a faster accumulation of P than N in human‐impacted freshwater ecosystems, which could have large effects on the trophic webs and biogeochemical cycles of estuaries and coastal areas by freshwater loadings, and reinforce the importance of rehabilitating these ecosystems. 相似文献
35.
Recent advances in the study of long-distance dispersal of aquatic invertebrates via birds 总被引:2,自引:0,他引:2
Although Darwin pioneered the study of long‐distance dispersal (LDD) of aquatic invertebrates via waterbirds, it remains in its infancy as a modern discipline. A handful of recent studies have quantified internal or external transport in the field, confirming that a variety of long‐distance migrants carry invertebrates both internally and externally. These studies show that variation in the morphology of vectors influences the frequency and size of propagules transported, and suggest that more invertebrate groups disperse via birds than was previously thought. Dispersal limitation has mainly been investigated for zooplankton in small experimental systems from which waterbirds were effectively excluded, and the extent of such limitation for invertebrate populations in wetlands interconnected by waterbird movements remains unclear. We expect that the spatial and temporal scales at which dispersal limitation constrains geographical ranges, species richness and genetic structure of invertebrates depends partly on the density of migratory birds using the area. Birds may have a major role in the expansion of exotic species. We propose several avenues for future research. There is a particular need for more quantitative studies of LDD by birds that will enable modellers to assess its role in maintaining invertebrate biodiversity among increasingly fragmented wetlands and in the face of climate change, as well as in the spread of invasive species. 相似文献
36.
The American brine shrimp as an exotic invasive species in the western Mediterranean 总被引:3,自引:0,他引:3
Francisco Amat Francisco Hontoria Olga Ruiz Andy J. Green Marta I. Sánchez Jordi Figuerola Francisco Hortas 《Biological invasions》2005,7(1):37-47
The hypersaline environments and salterns present in the western Mediterranean region (including Italy, southern France, the
Iberian Peninsula and Morocco) contain autochthonous forms of the brine shrimp Artemia, with parthenogenetic diploid and tetraploid strains coexisting with the bisexual species A. salina. Introduced populations of the American brine shrimp A. franciscana have also been recorded in these Mediterranean environments since the 1980s. Based on brine shrimp cyst samples collected
in these countries from 1980 until 2002, we were able to establish the present distribution of autochthonous brine shrimps
and of A. franciscana, which is shown to be an expanding invasive species. The results obtained show that A. franciscana is now the dominant Artemia species in Portuguese salterns, along the French Mediterranean coast and in Cadiz bay (Spain). Co-occurrence of autochthonous
(parthenogenetic) and American brine shrimp populations was observed in Morocco (Mar Chica) and France (Aigues Mortes), whereas
A. franciscana was not found in Italian cyst samples. The results suggest these exotic A. franciscana populations originate as intentional or non-intentional inoculations through aquacultural (hatchery effluents) or pet market
activities, and suggest that the native species can be rapidly replaced by the exotic species.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
37.
38.
Jordi Vayreda Jordi Martinez‐Vilalta Marc Gracia Javier Retana 《Global Change Biology》2012,18(3):1028-1041
Most temperate forests are accumulating carbon (C) and may continue to do so in the near future. However, the situation may be different in water‐limited ecosystems, where the potentially positive effects of C and N fertilization and rising temperatures interact with water availability. In this study, we use the extensive network of plots of two consecutive Spanish national forest inventories to identify the factors that determine the spatial variation of the C stock change, growth, and mortality rate of forests in Peninsular Spain (below‐ and aboveground). We fitted general linear models to assess the response of C stock change and its components to the spatial variability of climate (in terms of water availability), forest structure (tree density and C stock), previous forest management, and the recent warming trend. Our results show that undisturbed forests in Peninsular Spain are accumulating C at a rate of ~1.4 Mg C ha?1 yr?1, and that forest structural variables are the main determinants of forest growth and C stock change. Water availability was positively related to growth and C accumulation. On the other hand, recent warming has reduced growth rate and C accumulation, especially in wet areas. Spatial variation in mortality (in terms of C loss) was mostly driven by differences in growth rate across plots, and was consistent with ‘natural’, self‐thinning dynamics related to the recent abandonment of forest management over large areas of Spain, with the consequent increase in tree density and competition. Interestingly, the negative effect of warming on forest C accumulation disappears if only managed stands are considered, emphasizing the potential of forest management to mitigate the effects of climate change. However, the effect of forest management was weak and, in some cases, not significant, implying the need of further research on its impact. 相似文献
39.
Acceleration of cyanobacterial dominance in north temperate‐subarctic lakes during the Anthropocene
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Zofia E. Taranu Irene Gregory‐Eaves Peter R. Leavitt Lynda Bunting Teresa Buchaca Jordi Catalan Isabelle Domaizon Piero Guilizzoni Andrea Lami Suzanne McGowan Heather Moorhouse Giuseppe Morabito Frances R. Pick Mark A. Stevenson Patrick L. Thompson Rolf D. Vinebrooke 《Ecology letters》2015,18(4):375-384
Increases in atmospheric temperature and nutrients from land are thought to be promoting the expansion of harmful cyanobacteria in lakes worldwide, yet to date there has been no quantitative synthesis of long‐term trends. To test whether cyanobacteria have increased in abundance over the past ~ 200 years and evaluate the relative influence of potential causal mechanisms, we synthesised 108 highly resolved sedimentary time series and 18 decadal‐scale monitoring records from north temperate‐subarctic lakes. We demonstrate that: (1) cyanobacteria have increased significantly since c. 1800 ce , (2) they have increased disproportionately relative to other phytoplankton, and (3) cyanobacteria increased more rapidly post c. 1945 ce . Variation among lakes in the rates of increase was explained best by nutrient concentration (phosphorus and nitrogen), and temperature was of secondary importance. Although cyanobacterial biomass has declined in some managed lakes with reduced nutrient influx, the larger spatio‐temporal scale of sedimentary records show continued increases in cyanobacteria throughout the north temperate‐subarctic regions. 相似文献
40.
Emili Saló Ana Maria Muñoz-Mármol José Ramon Bayascas-Ramirez Jordi Garcia-Fernàndez Agusti Miralles Andreu Casali Montserrat Corominas Jaume Baguñá 《Hydrobiologia》1995,305(1-3):269-275
To identify potential pattern control and cell determination and/or differentiation genes in the freshwater planarian Dugesial (G.) tigrina, we searched for homeobox genes of different types in the genome of this primitive metazoan. We applied two basic approaches: 1) Screening the cDNA library with degenerate oligonucleotides corresponding to the most conserved amino acid sequence from helix-3 of the homeodomain of each family; and 2) PCR amplification of genomic DNA or cDNA, using two sets of degenerated oligonucleotides corresponding to helices 1 and 3 of the homeodomain or two specific domains of the POU family. Using the first strategy we have identified and characterized two tissue-specific cell determination and/or differentiation NK-type homeobox genes. Using the second strategy we have identified several homeobox genes that belong to the HOM/Hox, paired (prd) or POU families. 相似文献