23736 research outputs found
Sort by
Aerosol measurement methods to quantify spore emissions from fungi and cryptogamic covers in the Amazon
No full textBioaerosols are considered to play a relevant role in atmospheric processes, but their sources, properties, and spatiotemporal distribution in the atmosphere are not yet well characterized. In the Amazon Basin, primary biological aerosol particles (PBAPs) account for a large fraction of coarse particulate matter, and fungal spores are among the most abundant PBAPs in this area as well as in other vegetated continental regions. Furthermore, PBAPs could also be important ice nuclei in Amazonia. Measurement data on the release of fungal spores under natural conditions, however, are sparse. Here we present an experimental approach to analyze and quantify the spore release from fungi and other spore-producing organisms under natural and laboratory conditions. For measurements under natural conditions, the samples were kept in their natural environment and a setup was developed to estimate the spore release numbers and sizes as well as the microclimatic factors temperature and air humidity in parallel to the mesoclimatic parameters net radiation, rain, and fog occurrence. For experiments in the laboratory, we developed a cuvette to assess the particle size and number of newly released fungal spores under controlled conditions, simultaneously measuring temperature and relative humidity inside the cuvette. Both approaches were combined with bioaerosol sampling techniques to characterize the released particles using microscopic methods. For fruiting bodies of the basidiomycetous species, Rigidoporus microporus, the model species for which these techniques were tested, the highest frequency of spore release occurred in the range from 62 % to 96 % relative humidity. The results obtained for this model species reveal characteristic spore release patterns linked to environmental or experimental conditions, indicating that the moisture status of the sample may be a regulating factor, whereas temperature and light seem to play a minor role for this species. The presented approach enables systematic studies aimed at the quantification and validation of spore emission rates and inventories, which can be applied to a regional mapping of cryptogamic organisms under given environmental conditions. © Author(s) 2020
Phylogenetic and morphological analyses of species of Marasmius sect. Marasmius from the Atlantic Rainforest, Brazil
No full textMarasmius is a genus of mushroom-forming fungi known to harbor a large diversity of species and morphological structures. To date, sections Globulares, Leveilleani, Marasmius, Neosessiles, and Sicci (traditional view) are confirmed in Marasmius s.s. This study focused on the taxa of Marasmius sect. Marasmius, with 18 species from the Atlantic Rainforest of Southeastern Brazil herein included in morphological and phylogenetic analyses based on nrITS data, along with species of the section from various tropical and temperate areas of the World. Seven new species are described: Marasmius alienigenus sp. nov., M. avellaneus sp. nov., M. gracilis sp. nov., M. longibasidiatus sp. nov., M. subputtemansii sp. nov., M. subvigintifolius sp. nov., and M. ypyrangensis sp. nov. Additionally, Marasmius sect. Marasmius subsect. Horriduli is herein emended based on evidences from phylogenetic and morphological analyses. Subsection Horriduli circumscribes foliicolous species producing basidiomata containing Chrysochaetes-type elements in the pileipellis and lamellar edge. This prompts the perspective of a pluralistic view in how characterizing structures of the pileipellis and cheilocystidia to replace the paradigmatic dichotomy Rotalis-Siccus in classification. © 2020, Springer-Verlag GmbH Austria, part of Springer Nature
Molecular taxonomy and phylogenetic inferences of Bichromomyia flaviscutellata complex based on the COI gene DNA barcode region
No full textLeishmaniasis is considered one of the six most important infectious diseases in the world. In spite of its importance, the leishmaniasis is one of the world's most neglected tropical diseases. Bichromomyia flaviscutellata sensu lato is a complex composed of at least three species: B. flaviscutellata sensu stricto, B. reducta and B. olmeca. The latter is composed of three subspecies: B. olmeca olmeca, B. olmeca bicolor and B. olmeca nociva, which are distributed from Central America to South America. Of these, B. flaviscutellata s.s. is recognized as the main vector of Leishmania amazonensis in Brazil. The present study aimed to identify molecularly the species and subspecies of the B. flaviscutellata complex using the 5′ region of the COI gene (Barcode region). A total of 44 specimens, comprising 22 B. flaviscutellata s.s. and 22 B. olmeca nociva, were analyzed from six localities in the Brazilian Amazon: five in the State of Amazonas (Autazes, Manaus, Pitinga, Novo Airão, and Rio Preto da Eva), and one in the State of Pará (Serra do Cachorro). Three sequences from B. olmeca olmeca and one of B. olmeca bicolor from GenBank were also added to the dataset, totaling 48 sequences with a length of 549 base pairs (bp). The total dataset generated 28 haplotypes and four disconnected networks. Phylogenetic analyses using three algorithms (Neighbor-Joining [NJ], Maximum Likelihood [ML] and Bayesian Inference [BI]) generated similar topologies and most clades were from moderately to highly supported. The phylogenetic relationship, together with genetic distance values (1%) and haplotypes networks, confirm the position of B. olmeca bicolor as a subspecies of B. olmeca olmeca. However, B. olmeca nociva was closer phylogenetically to B. flaviscutellata s.s. than to B. olmeca olmeca and B. olmeca bicolor. Additionally, the haplotype network separated B. olmeca nociva from B. olmeca olmeca and B. olmeca bicolor. These findings, combined with previous morphological data, suggest that the B. olmeca nociva should be elevated to full-species status. The findings of this study also found that B. flaviscutellata s.s. populations may be in process of forming lineages. © 2020 Elsevier B.V
Leaf consumption by invertebrate aquatic shredders in the Amazon: effects of climate change and microbial conditioning
No full textWe grew leaves of Montrichardia arborescens in four microcosm chambers with different temperatures and CO2 concentrations simulating the scenarios of expected climate change. These leaves were used to feed shredders (Phylloicus) and to assess the effects of changes in leaf quality on their consumption. We also evaluated the effect of detritus conditioning by microorganisms on leaf consumption. We hypothesized that leaves of plants grown under different environmental conditions could offer substrata of different qualities to microorganisms colonizing them, and, consequently the shredder consumption rate would differ according to leaf conditioning. The microcosm chambers for plant growth simulated three different combined air temperature and CO2 scenarios, relative to the real-time (control) current conditions in Manaus-Brazil. The leaf consumption experiment was performed only in the control chamber. Specific leaf area was positively affected by predicted climate change, while tannins were detected only in leaves of plants grown in chambers simulating a changed climate. Other leaf detritus parameters were similar in all chambers. Shredders showed higher consumption rates in leaves developed under mild and intermediate conditions in relation to control. Shredder consumption was similar in conditioned and unconditioned treatments. Thus, shredder consumption was influenced more by the intrinsic quality of leaves than by microorganism conditioning, but we were not able to show effects of climate change on leaf quality that could explain differences in shredder consumption. © 2020, The Japanese Society of Limnology
Diamantina: An endemic new genus of Neotropical Atalophlebiinae (Ephemeroptera: Leptophlebiidae) evidenced by morphological and molecular data
Full text linkA new genus and species is described based on nymphs and adults collected exclusively at the Chapada Diamantina National Park, in Brazil. The generic category of this new taxon was tested by reanalyzing a morphological dataset used to access the phylogenetic relationships of species of Ulmeritus and Ulmeritoides and by the use of molecular analysis, using two different genes. Both analysis corroborated the new taxon belongs to a new genus and species, sister group of Ulmeritus-Ulmeritoides, herein described as Diamantina ulmeri gen et sp. nov. Among members of this complex, Diamantina gen nov. presents a unique apomorphy: absence of setae on lateral margins of abdominal segments. Diagnostic features include the anterior position of the proximal row of setae on dorsal surface of labrum, the U shaped emargination of labrum, eyes of male imago widely separated and shape of penis lobes. © 2019 Elsevier Gmb
First record to Brazil of one genera and seven species of psychodidae (Diptera) with further new records for 10 countries on the neotropics
Full text linkWith a big territory and variety of biomes, Brazil is one of the most diverse countries in the World, with insects massively contributing to this diversity. Although presenting impressive numbers, many groups are poorly known concerning their diversity and distribution. Also, the knowledge of the species diversity is very heterogeneous when comparing Brazilian states and regions. With a recent review of part of Lawrence Quate’s collection deposited at Natural History Museum of Los Angeles County, more than 70 new geographical records for Psychodidae species were found on the Neotropics, including one genera (Eurygarka) and seven species first recorded to Brazil. The complete known distribution of these species was compiled and is presented along with new records for other 11 countries of the Neotropical region. On the Brazilian territory, most of the new records are for the state of Rondônia, on the northern region, followed by Minas Gerais, on the southeastern region. © 2020, Universidade de Sao Paulo. All rights reserved
Temperature effects on the LDH gene expression of the Amazonian ornamental fish Paracheirodon axelrodi
No full textPineapple (Ananás comosus) leaves ash as a solid base catalyst for biodiesel synthesis
No full textHomogeneous catalysts used for biodiesel synthesis have several limitations, including non-recoverability/reusability, saponification, emulsification, equipment corrosion, and environmental pollution. To overcome these limitations, we synthesized a novel catalyst via calcination of pineapple leaves waste. This catalyst was characterized by X-ray powder diffraction, X-ray fluorescence, Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and soluble alkalinity measurements. The catalyst's activity with regards to soybean oil transesterification was analyzed, and multiple process parameters (temperature, catalyst amount, reaction time, and methanol:oil molar ratio) were examined. A high catalytic activity, probably related to the 85 wt% content of alkali/alkali metals (K, Ca and Mg), was observed after a 30 min reaction time, 60 °C, 4 wt% of catalyst, oil to methanol molar ratio of 1:40, reaching an oil to biodiesel conversion above 98%. We conclude that the novel catalyst presented here is efficient, cost-effective, and sustainable, while simultaneously abundant waste is reduced. © 2020 Elsevier Lt
Tambaqui (Colossoma macropomum) acclimated to different tropical waters from the Amazon basin shows specific acute-stress responses
No full textA new species of Rheotanytarsus Thienemann & Bause (Diptera: Chironomidae) from Peruvian Andes, with updated key to South American species
No full textRheotanytarsus is a speciose genus, currently composed by more than 100 nominal species distributed worldwide, 19 are known from the Neotropical region, four from South America and only one is registered for Peru. In the present study, a new species is described and illustrated based on males collected in the Peruvian Andes. In addition, the key to the South American species is updated and a distribution map of them is provided. Rheotanytarsus amaru sp. n. is easily distinguished from the congeneric species by the dark general coloration and the hypopygial morphology. Copyright © 2020 Magnolia Pres