In eukaryotes, the high-mobility-group (HMG) nuclear factors are highly conserved throughout evolution and are divided into three families, including HGMB, characterized by an HMG box domain. Some HMGB factors are DNA structure specific and preferentially interact with distorted DNA sequences, trigger DNA bending, and hence facilitate the binding of nucleoprotein complexes that in turn activate or repress transcription. In Plasmodium falciparum, two HMGB factors were predicted: PfHMGB1 and PfHMGB2. They are small proteins, under 100 amino acids long, encompassing a characteristic HMG box domain closely related to box B of metazoan factors, which comprises two HMG box domains, A and B, in tandem. Computational analyses supported the conclusion that the Plasmodium proteins were genuine architectural HMGB factors, and in vitro analyses performed with both recombinant proteins established that they were able to interact with distorted DNA structures and bend linear DNA with different affinities. These proteins were detected in both asexual-and gametocyte-stage cells in Western blotting experiments and mainly in the parasite nuclei. PfHMGB1 is preferentially expressed in asexual erythrocytic stages and PfHMGB2 in gametocytes, in good correlation with transcript levels of expression. Finally, immunofluorescence studies revealed differential subcellular localizations: both factors were observed in the nucleus of asexual-and sexual-stage cells, and PfHMGB2 was also detected in the cytoplasm of gametocytes. In conclusion, in light of differences in their levels of expression, subcellular localizations, and capacities for binding and bending DNA, these factors are likely to play nonredundant roles in transcriptional regulation of Plasmodium development in erythrocytes.Malaria is the most important parasitic disease in the world, and of the 300 to 500 million cases each year, approximately 2 million people die. Among the four species of malaria parasites infecting humans, Plasmodium falciparum causes the highest morbidity and mortality. Global efforts to eradicate malaria have failed, and there is presently no effective vaccine available. Therefore, a greater understanding of parasite biology throughout development is urgently needed in order for novel therapeutic strategies to control malaria to be proposed.During the erythrocytic life cycle, intense multiplication of parasites takes place, as well as gametocyte differentiation associated with cell cycle arrest. These different developmental pathways require the coordinated and modulated expression of diverse sets of genes, involving transcriptional, epigenetic, and posttranscriptional regulation. Currently, it is commonly accepted that general mechanisms involved in gene regulation in eukaryotes also operate in P. falciparum (25,32,33). Nevertheless, elucidation of the molecular mechanisms involved in transcriptional regulation in Plasmodium is still challenging.Even if very little is known about the cis-and trans-regulatory elements of the parasite, Plasmodium genes exh...
This article aims to characterize a network which appeared between distant places such as London, Glasgow, Paris, and Madrid and places such as Quito, Guayaquil, Archidona, and Ambato. The network was fostered by several naturalists who, while residing in the territory that in 1830 had just been named "Ecuador", came into contact with European scientists through various means. This document highlights the relationship and interests of the people who participated in this transnational network for the exchange of specimens, knowledge, ideas, and books, while emphasizing the local contexts of these scientists and their roles in the network
Abstract. Greenspaces within broader ecosystem-based disaster risk reduction (Eco-DRR) strategies provide multiple benefits to society, biodiversity, and addressing climate breakdown. In this study, we investigated urban growth, its intersection with hazards, and the availability of greenspace for disaster risk reduction (DRR) in the city of Quito, Ecuador, which experiences multiple hazards including landslides, floods, volcanoes, and earthquakes. We used satellite data to quantify urban sprawl and developed a workflow incorporating high-resolution digital elevation models (DEMs) to identify potential greenspaces for emergency refuge accommodation (DRR greenspace), for example, following an earthquake. Quito's historical urban growth totalled ∼ 192 km2 for 1986–2020 and was primarily on flatter land, in some cases crossed by steep ravines. By contrast, future projections indicate an increasing intersection between easterly urbanisation and steep areas of high landslide susceptibility. Therefore, a timely opportunity exists for future risk-informed planning. Our workflow identified 18.6 km2 of DRR greenspaces, of which 16.3 km2 intersected with potential sources of landslide and flood hazards, indicating that hazard events could impact potential “safe spaces”. These spaces could mitigate future risk if designated as greenspaces and left undeveloped. DRR greenspace overlapped 7 % (2.5 km2) with municipality-designated greenspace. Similarly, 10 % (1.7 km2) of municipality-designated “safe space” for use following an earthquake was classified as potentially DRR suitable in our analysis. For emergency refuge, currently designated greenspaces could accommodate ∼ 2 %–14 % (depending on space requirements) of Quito's population within 800 m. This increases to 8 %–40 % considering all the potential DRR greenspace mapped in this study. Therefore, a gap exists between the provision of DRR and designated greenspace. Within Quito, we found a disparity between access to greenspaces across socio-economic groups, with lower income groups having less access and further to travel to designated greenspaces. Notably, the accessibility of greenspaces was high overall with 98 % (2.3 million) of Quito's population within 800 m of a designated greenspace, of which 88 % (2.1 million) had access to potential DRR greenspaces. Our workflow demonstrates a citywide evaluation of DRR greenspace potential and provides the foundation upon which to evaluate these spaces with local stakeholders. Promoting equitable access to greenspaces, communicating their multiple benefits, and considering their use to restrict propagating development into hazardous areas are key themes that emerge for further investigation.
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