The interaction of Q analogs, particularly hydroxydecyl benzoquinone (idebenone), with the respiratory complexes of heart mitochondria

We have studied the interaction of idebenone (2,3-dimethoxy-5-methy-6- (10-hydroxy)decyl-1,4-benzoquinone) with the energy-conserving complexes of the respiratory chain in beef heart mitochondria and compared its energetic efficiency with that of other analogs of coenzyme Q. Idebenone is a very effective substrate for succinate:Q reductase and ubiquinol:cytochrome c reductase, but it is clearly a poor substrate for NADH:Q reductase (complex I). Indeed, idebenone is a strong inhibitor of both the redox and proton pumping activity of complex I, showing effects in part similar to those of coenzyme Q-2. However, the mechanism of idebenone interaction with complex I may be different from that of Q-2 because of its different sensitivity to inhibitors. The possible relevance of the present findings to the therapeutic use of idebenone is discussed

Relação entre diferentes espécies de formigas e a mirmecófita Cordia nodosa Lamarck (Boraginaceae) em áreas de mata ripária na Amazônia mato-grossense Relationship among different plant-ants and its myrmecophite host Cordia nodosa Lamarck (Boraginaceae) in a riparian Mato Grosso Amazonian forest

Os benefícios obtidos por um organismo em uma associação mutualística podem variar em função de fatores ambientais, bem como entre as diferentes espécies que podem estar associadas. Neste trabalho demonstramos que quatro espécies de formigas, Crematogaster brasiliensis, Allomerus octoarticulatus e duas não identificadas do gênero Azteca podem ser encontradas associadas à mirmecófita Cordia nodosa em florestas ripárias sul-amazônicas. Essa composição de espécies de formigas é mais similar a encontrada na Amazônia Andina do que aquela da Amazônia Central brasileira. A colonização por formigas parece ser determinante, pois diminuiu a herbivoria e, consequentemente, aumentou a probabilidade de C. nodosa produzir frutos. Adicionalmente, mesmo não havendo diferença na herbivoria entre plantas colonizadas pelas diferentes espécies de formigas, a probabilidade de uma planta colonizada por formigas do gênero Allomerus produzir frutos é menor do que quando colonizadas pelas outras espécies de formigas. Esse estudo demonstra a dependência de C. nodosa pela colonização de formigas para sua reprodução. Contudo, conforme outros estudos realizados em outras áreas da Amazônia demonstram, nossos resultados também sugerem que Allomerus pode estar castrando as plantas hospedeiras, agindo como parasita em toda a sua distribuição geográfica.<br>The benefits obtained by an organism when involved in a mutualistic interaction vary depending on environmental factors, as well as among the identity of the involved species. In this study, we showed that four ant species, Crematogaster brasiliensis, Allomerus octoarticulatus, and two unidentified Azteca species can be found associated to the myrmecophite Cordia nodosa in riparian forests in the South of Amazonia. This composition of ant-associated species is more similar in forests of Andean Amazon than in Central Amazonia. The colonization of an ant colony on C. nodosa seems to be vital in order to decrease herbivory, as increased the probability of a plant sets fruits. Moreover, even though we did not find significant differences in herbivory among plants colonized by different ant species, the probability of a plant produces fruits is much lower when it is colonized by Allomerus ants. Overall, this study shows that C. nodosa depends on ants to reproduce. However, based on other empirical studies across the Amazon, our results also suggest that Allomerus ants can act as flower castrator, acting as a parasite over its geographic range

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora