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- Bryois, J., et al.
(author)
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Genetic identification of cell types underlying brain complex traits yields insights into the etiology of Parkinson’s disease
- 2020
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In: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 52:5, s. 482-493
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Journal article (peer-reviewed)abstract
- Genome-wide association studies have discovered hundreds of loci associated with complex brain disorders, but it remains unclear in which cell types these loci are active. Here we integrate genome-wide association study results with single-cell transcriptomic data from the entire mouse nervous system to systematically identify cell types underlying brain complex traits. We show that psychiatric disorders are predominantly associated with projecting excitatory and inhibitory neurons. Neurological diseases were associated with different cell types, which is consistent with other lines of evidence. Notably, Parkinson’s disease was genetically associated not only with cholinergic and monoaminergic neurons (which include dopaminergic neurons) but also with enteric neurons and oligodendrocytes. Using post-mortem brain transcriptomic data, we confirmed alterations in these cells, even at the earliest stages of disease progression. Our study provides an important framework for understanding the cellular basis of complex brain maladies, and reveals an unexpected role of oligodendrocytes in Parkinson’s disease. © 2020, The Author(s), under exclusive licence to Springer Nature America, Inc.
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- Winston, A, et al.
(author)
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Host and disease factors are associated with cognitive function in European HIV-infected adults prior to initiation of antiretroviral therapy
- 2016
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In: HIV Medicine. - : Wiley. - 1468-1293 .- 1464-2662. ; 17:6, s. 471-478
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Journal article (peer-reviewed)abstract
- OBJECTIVES: Deficits in cognitive function remain prevalent in HIV-infected individuals. The aim of this European multicentre study was to assess factors associated with cognitive function in antiretroviral therapy (ART)-naïve HIV-infected subjects at the time of enrolment in the NEAT 001/Agence Nationale de Recherche sur le SIDA (ANRS) 143 study.METHODS: Prior to starting ART, seven cognitive tests exploring domains including episodic memory, verbal fluency, executive function and psychomotor speed were administered with scores standardized to z-score using the study population sample mean and standard deviation. The primary measure was overall z-score average (NPZ). We assessed associations between baseline factors and test results using multivariable regression models.RESULTS: Of 283 subjects with baseline cognitive assessments, 90% were male and 12% of black ethnicity. Median (interquartile range) age, years of education, years of known HIV infection, baseline CD4 count and baseline HIV RNA were 39 (31, 47) years, 13 (11, 17) years, 1 (0, 4) years, 344 (279, 410) cells/μL and 4.74 (4.28, 5.14) log10 HIV-1 RNA copies/mL, respectively. Forty per cent were current smokers. Factors significantly associated with poorer overall cognitive performance in multivariable models included older age, shorter duration of education, black ethnicity, lower height, and lower plasma HIV RNA.CONCLUSIONS: In this large, European-wide, ART-naïve population with relatively preserved immunity and early HIV infection, cognitive function scores at the time of ART initiation were associated with demographic and HIV-disease factors.
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- Araujo, R., et al.
(author)
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TRADE-OFFS BETWEEN LIFE-HISTORY TRAITS AT RANGE-EDGE AND CENTRAL LOCATIONS
- 2015
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In: Journal of Phycology. - : Wiley. - 0022-3646. ; 51:4, s. 808-818
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Journal article (peer-reviewed)abstract
- The allocation of resources to different life-history traits should represent the best compromise in fitness investment for organisms in their local environment. When resources are limiting, the investment in a specific trait must carry a cost that is expressed in trade-offs with other traits. In this study, the relative investment in the fitness-related traits, growth, reproduction and defence were compared at central and range-edge locations, using the seaweed Ascophyllum nodosum as a model system. Individual growth rates were similar at both sites, whereas edge populations showed a higher relative investment in reproduction (demonstrated by a higher reproductive allocation and extended reproductive periods) when compared to central populations that invested more in defence. These results show the capability of A. nodosum to differentially allocate resources for different traits under different habitat conditions, suggesting that reproduction and defence have different fitness values under the specific living conditions experienced at edge and central locations. However, ongoing climate change may threaten edge populations by increasing the selective pressure on specific traits, forcing these populations to lower the investment in other traits that are also potentially important for population fitness.
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| 6. |
- Araujo, R., et al.
(author)
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The role of disturbance in differential regulation of co-occurring brown algae species: Interactive effects of sediment deposition, abrasion and grazing on algae recruits
- 2012
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In: Journal of Experimental Marine Biology and Ecology. - : Elsevier BV. - 0022-0981. ; 422-423, s. 1-8
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Journal article (peer-reviewed)abstract
- Disturbance is an important structuring factor in intertidal communities. This study aimed at experimentally testing the effects of three important sources of disturbance to intertidal rocky habitats (abrasion, sediment deposition and herbivory) on the survivorship and growth of embryos of canopy forming fucoid species (Fucus vesiculosus and Fucus serratus). Natural levels of sediment deposition and herbivore density were characterized and the temporal variation of populations of both species was followed. The experimental study showed that the survivorship of F. serratus embryos was negatively affected by herbivory but growth was enhanced in the presence of abrasion and herbivores. F. vesiculosus suffered the interactive negative effects of the three sources of disturbance tested, although abrasion was the most important factor affecting mortality rates of embryos. Conversely, none of the tested sources of disturbance significantly affected growth of embryos. These results highlight the importance of disturbance events in regulating species interactions which might be particularly relevant for population dynamics and persistence at the geographical borders of species' distribution. (C) 2012 Elsevier B.V. All rights reserved.
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| 8. |
- Sampaio, E., et al.
(author)
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Interaction strength between different grazers and macroalgae mediated by ocean acidification over warming gradients
- 2017
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In: Marine Environmental Research. - : Elsevier BV. - 0141-1136 .- 1879-0291. ; 125, s. 25-33
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Journal article (peer-reviewed)abstract
- Since the past century, rising CO2 levels have led to global changes (ocean warming and acidification) with subsequent effects on marine ecosystems and organisms. Macroalgae-herbivore interactions have a main role in the regulation of marine community structure (top-down control). Gradients of warming prompt complex non-linear effects on organism metabolism, cascading into altered trophic interactions and community dynamics. However, not much is known on how will acidification and grazer assemblage composition shape these effects. Within this context, we aimed to assess the combined effects of warming gradients and acidification on macroalgae-herbivore interactions, using three cosmopolitan species, abundant in the Iberian Peninsula and closely associated in nature: the amphipod Melita palmata, the gastropod Gibbula umbilicalis, and the green macroalga Ulva rigida. Under two CO2 treatments (triangle CO2 similar or equal to 450 mu atm) across a temperature gradient (13.5, 16.6, 19.9 and 22.1 degrees C), two mesocosm experiments were performed to assess grazer consumption rates and macroalgae-herbivore interaction, respectively. Warming (Experiment I and II) and acidification (Experiment II) prompted negative effects in grazer's survival and species-specific differences in consumption rates. M. palmata was shown to be the stronger grazer per biomass (but not per capita), and also the most affected by climate stressors. Macroalgae-herbivore interaction strength was markedly shaped by the temperature gradient, while simultaneous acidification lowered thermal optimal threshold. In the near future, warming and acidification are likely to strengthen top-down control, but further increases in disturbances may lead to bottom-up regulated communities. Finally, our results suggest that grazer assemblage composition may modulate future macroalgae-herbivore interactions.
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