Background: Neuroinflammation has been implicated in various brain pathologies characterized by hypoxia and ischemia. Astroglia play an important role in the initiation and propagation of hypoxia/ischemia-induced inflammation by secreting inflammatory chemokines that attract neutrophils and monocytes into the brain. However, triggers of chemokine up-regulation by hypoxia/ischemia in these cells are poorly understood. Hypoxia-inducible factor-1 (HIF-1) is a dimeric transcriptional factor consisting of HIF-1α and HIF-1β subunits. HIF-1 binds to HIF-1-binding sites in the target genes and activates their transcription. We have recently shown that hypoxia-induced expression of IL-1β in astrocytes is mediated by HIF-1α. In this study, we demonstrate the role of HIF-1α in hypoxia-induced up-regulation of inflammatory chemokines, human monocyte chemoattractant protein-1 (MCP-1/CCL2) and mouse MCP-5 (Ccl12), in human and mouse astrocytes, respectively.
Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale.
Although the practice of cultivating mass fl owering crops (MFCs) is seen as a means of counteracting the widespread decline of insect pollinators, no study to-date has evaluated whether the increased pollinator abundance associated with MFCs infl uences pollinator visits to assemblages of adjacent native, non-crop plant species (pollinator ' spill-over ' ). In this study we quantifi ed bumblebee abundance along hedgerow transects in MFC (fi eld bean) vs non-MFC (wheat) margins. Surveys were conducted on east and west-facing margins twice daily (morning and afternoon) for three or four days during the main MFC fl owering period (June) over four years involving paired bean and wheat fi elds in Devon and Cornwall, southwest England. Although no single bumblebee species showed any consistent change in relative frequency, when taken across all years and bumblebee species combined, we observed twice as many bumblebees visiting fl owers adjacent to the MFC. However, when we compared bumblebee activity along hedgerow transects two weeks after bean fl owering, there was no diff erence between crops. We thus conclude that although there is evidence for pollinator spillover from the bean MFC to nearby semi-natural habitat, the eff ect is comparatively short lived and not specifi c to any single bumblebee species. We also suggest that while pollinator services to native plant species might be briefl y enhanced by MFC cultivation, the possible repercussions of bumblebee spill-over from MFCs to semi-natural habitats and the other pollinator groups they support should be evaluated before MFC cultivation is considered as a means of conserving declining bumblebee populations.
The macrophyte swamp stonecrop has invaded a wide range of wetland habitats across Europe. An experiment was conducted within an invaded fen habitat, which tested whether the presence of grazing disturbance affected the relative abundance of swamp stonecrop, and whether any detected effect was suppressive or facilitative. The abundance of swamp stonecrop and co-occurring resident plants was monitored within fenced grazing exclosures and in adjacent unfenced plots. Swamp stonecrop abundance was higher in the unfenced plots compared to the fenced exclosures (t(87) = 28.974, P < 0.001), whereas the abundance of co-occurring plants was higher in the fenced exclosures compared to the unfenced plots (t(87) = 6.264, P < 0.001). These results indicate that the presence of large vertebrates could facilitate a higher abundance of swamp stonecrop in situations where competitive resident plant species were selectively removed by these grazing animals.
Background: As agriculture has intensified, many once-common wildflowers have declined in arable landscapes, which has widespread implications for associated ecosystem services. The incorporation of sustainable practices, for example, growing living mulches (in-field, non-crop plant ground cover, maintained during the target crop growing season), can boost arable biodiversity, but few wildflower species have been utilised in this context. Aims: Our aim was to determine the suitability of arable wildflower species, once considered weeds, for use as living mulches. Methods: We first screened a number of arable wildflower species for germination when growing with a common cereal, barley (Hordeum vulgare). We then grew two (Centaurea cyanus and Scandix pecten-veneris) in pots in a glasshouse with and without barley, and grew barley alone to test the impact of the wildflowers on barley growth and biomass. Results: Neither of the wildflowers significantly negatively impacted barley biomass. Barley initially facilitated germination in S. pecten-veneris, but ultimately suppressed the aboveground biomass of both wildflowers. However, both wildflower species were able to coexist alongside barley. Conclusions: Our experiment provides evidence that wildflowers that were considered weeds in traditional agriculture have the potential to be grown alongside barley and could be incorporated as part of a living mulch.
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