31 research outputs found
Molecular phylogeny and character-mapping support the synonymy of Cordobia and Gallardoa in Mionandra (Malpighiaceae)
Background and aims – Cordobia, Gallardoa, Mionandra, and Peixotoa (Stigmaphylloid clade, Malpighiaceae) are four small, closely related genera comprising shrubs or lianas endemic to South American savannas, dry forests, and temperate steppes. Their generic limits have significantly changed in the last century, and past molecular phylogenetic studies of Malpighiaceae have not tested the morphological characters of this group to identify synapomorphies supporting these clades/genera. Material and methods – We sampled the monospecific Cordobia and Gallardoa, one species of Mionandra (out of 2 spp.), nine species of Peixotoa (out of 29 spp.), and a single species of Camarea and Janusia as outgroups. Bayesian and Maximum Likelihood analyses were carried out for this clade based on five molecular markers (i.e. ETS, ITS, PHYC, matK, and ndhF). A set of 16 macromorphological characters was scored and coded for identifying synapomorphies under the Maximum Likelihood criteria. Key results – Our molecular phylogeny recovered Peixotoa as monophyletic and sister to the clade comprising Cordobia + Gallardoa + Mionandra, strongly corroborating previous phylogenetic studies of Malpighiaceae. The character-mapping analyses recovered two synapomorphies supporting the Cordobia + Gallardoa + Mionandra + Peixotoa clade, six supporting Mionandra s.l. (i.e. Cordobia + Gallardoa + Mionandra), and five supporting Peixotoa. Cordobia and Gallardoa are proposed as synonyms of Mionandra, alongside the necessary combinations, typifications, and identification keys. Conclusions – Morphological characters related to the degree of connation of the stipules, leaf indumentum type, petiole length, inflorescence architecture, number of flowers per inflorescence, presence of a peduncle in the 1-flowered cincinni, sepal connation, posture and texture, petal width and margin integrity, staminode presence, shape and size, and the shape of the apex of styles were key in circumscribing these lineages. Mionandra s.l. is proposed and characterised, including a new combination, an identification key to distinguish its species, a distribution map, and taxonomy notes
The fate of acetic acid during glucose co-metabolism by the spoilage yeast Zygosaccharomyces bailii
Zygosaccharomyces bailii is one of the most widely represented spoilage yeast species, being able to metabolise acetic acid in the presence of glucose. To clarify whether simultaneous utilisation of the two substrates affects growth efficiency, we examined growth in single- and mixed-substrate cultures with glucose and acetic acid. Our findings indicate that the biomass yield in the first phase of growth is the result of the weighted sum of the respective biomass yields on single-substrate medium, supporting the conclusion that biomass yield on each substrate is not affected by the presence of the other at pH 3.0 and 5.0, at least for the substrate concentrations examined. In vivo(13)C-NMR spectroscopy studies showed that the gluconeogenic pathway is not operational and that [2-(13)C]acetate is metabolised via the Krebs cycle leading to the production of glutamate labelled on C(2), C(3) and C(4). The incorporation of [U-(14)C]acetate in the cellular constituents resulted mainly in the labelling of the protein and lipid pools 51.5% and 31.5%, respectively. Overall, our data establish that glucose is metabolised primarily through the glycolytic pathway, and acetic acid is used as an additional source of acetyl-CoA both for lipid synthesis and the Krebs cycle. This study provides useful clues for the design of new strategies aimed at overcoming yeast spoilage in acidic, sugar-containing food environments. Moreover, the elucidation of the molecular basis underlying the resistance phenotype of Z. bailii to acetic acid will have a potential impact on the improvement of the performance of S. cerevisiae industrial strains often exposed to acetic acid stress conditions, such as in wine and bioethanol production.This work was supported by Fundacao para a Ciencia e Tecnologia (FCT), Portugal Grant PTDC/AGR-ALI/102608/2008 and by project FCOMP-01-0124-FEDER- 007047 and by FEDER through POFC - COMPETE and national funds from FCT - project PEst-C/BIA/UI4050/2011. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
The origin and speciation of orchids
SummaryOrchids constitute one of the most spectacular radiations of flowering plants. However, their origin, spread across the globe, and hotspots of speciation remain uncertain due to the lack of an up-to-date phylogeographic analysis.We present a new Orchidaceae phylogeny based on combined high-throughput and Sanger sequencing data, covering all five subfamilies, 17/22 tribes, 40/49 subtribes, 285/736 genera, and c. 7% (1921) of the 29 524 accepted species, and use it to infer geographic range evolution, diversity, and speciation patterns by adding curated geographical distributions from the World Checklist of Vascular Plants.The orchids' most recent common ancestor is inferred to have lived in Late Cretaceous Laurasia. The modern range of Apostasioideae, which comprises two genera with 16 species from India to northern Australia, is interpreted as relictual, similar to that of numerous other groups that went extinct at higher latitudes following the global climate cooling during the Oligocene. Despite their ancient origin, modern orchid species diversity mainly originated over the last 5 Ma, with the highest speciation rates in Panama and Costa Rica.These results alter our understanding of the geographic origin of orchids, previously proposed as Australian, and pinpoint Central America as a region of recent, explosive speciation
Pervasive gaps in Amazonian ecological research
Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4
While the increasing availability of global databases on ecological communities has advanced our knowledge
of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In
the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of
Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus
crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced
environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian
Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by
2050. This means that unless we take immediate action, we will not be able to establish their current status,
much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio
Pervasive gaps in Amazonian ecological research
Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost
Estudo dos padrões de variabilidade intra e interespecifica em especies brasileiras de Cattleya Lindley (Orchidaceae-Laeliinae)
Orientador: Paulo Sodero MartinsDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: O principal objetivo deste trabalho foi estudar de forma genérica a variabilidade intra e interespecífica nas espécies brasileiras do gênero Cattleya Lindley. Cattleya é composto de aproximadamente 50 espécies neotropicais, das quais 30 são citadas para o Brasil e 25 são exclusivas deste país. Dentro deste objetivo pretendi inicialmente avaliar 6 sistemas de classificação propostos e 5 pares de espécies próximas que apresentavam problemas para identificação. Construí~então, mapas de distribuição baseados em materiais de 23 herbários do país, além dos locais de coleta das plantas do orquidário do Departamento de Genética ESALQ/USP. Em seguida, realizei um estudo morfométrico sobre 24, variáveis florais, utilizando Métodos de Agrupamento e Ordenação sobre um total de 1382 plantas em 73 populações de 23 espécies ... Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digitalAbstract: The main purpose of the present study was to assess the overall patterns of intra and interspecific variability in the Brazilian species of the genus Cattleya. This genus is composed of 50 neotropical species, of which 30 occur in Brazil and 25 are endemic to this country. In order to accomplish my purpose, I evaluated 6 c1assification systems ITom the literature and 5 c10se species pairs that present troublesome identification. Distribution maps based upon specimens From 23 Brazilian herbaria were outlined. I also plotted the collecting sites of the living plants in the- orchid colle-ction of the Departamento de Genética ESALQ/USP, Piracicaba, São Paulo, Brazil, which were used for morphometric studies. Morphometric methods used were Clustering upon Mahalanobis's Generalized Distance and Discriminant Analysis ... Note: The complete abstract is available with the full electronic digital thesis or dissertationsMestradoEcologiaMestre em Ciências Biológica
R\ue9vision taxinomique du genre Acianthera (Orchidaceae, Pleurothallidinae)
Volume: 12Start Page: 59End Page: 7