104 research outputs found

    Definition of species of pouched four-eyed opossums (Didelphidae, Philander)

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    We hypothesize phyletic relationships among taxa of the didelphid marsupial genus Philander, based on sequences of the mitochondrial cytochrome b gene. Data are available for six taxa recognized at either the specific or subspecific levels; P. opossum opossum Linneaus (eastern and northeastern Amazonia), P. opossum canus Osgood (western Amazonia), P. opossum fuscogriseus J. A. Allen (southeastern Central America), P. opossum frenata Olfers (southeastern Brazil), P. andersoni andersoni Osgood (northwestern Amazonia), and P. andersoni mcilhennyi Gardner and Patton (west-central Amazonia). Haplotype divergence is minimal to non-existent (<1% on average) between individuals within and among localities for each taxon. The taxon inhabiting the Atlantic forest of coastal Brazil (P. o. frenata) is highly divergent from all others, averaging nearly 14% in sequence divergence. Maximal divergence among haplotypes representative of the other taxa examined is <8%. The combination of phylogenetic relationships and local sympatry suggests a greater degree of species diversity for the genus than the two species P. opossum and P. andersoni. We recognize the Brazilian coastal P. frenata, as well as both P. andersoni and P. mcilhennyi, as valid species in addition to P. opossum. It is possible P. opossum is a composite, and that further studies will accord species status to the Middle American, western Amazonian, and eastern Amazonian-Guianan gray four-eyed opossums

    Expressão e análise antigênica da proteína RTP36 recombinante da amostra São Paulo de Ehrlichia canis para testes sorológicos

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    Ehrlichia canis is the main etiological agent of canine monocytic ehrlichiosis (CME), a globally canine infectious disease. In Brazil, CME is considered to be endemic, and its prevalence can reach 65% in some states. The diagnosis of ehrlichiosis is important for treatment and epidemiological purposes. The E. canis TRP36 (Tandem Repeat Protein) protein elicits the earliest acute-phase antibody response observed during the course of the disease. This study aimed to generate the recombinant TRP36 protein from E. canis São Paulo strain and to evaluate its potential as a tool for the serologic diagnosis of CME. The E. canis São Paulo isolate was cultivated in DH82 lineage cells, and its genomic DNA was obtained. The bacterial DNA fragment encoding the entire ORF of TRP36 was cloned into the pBAD/Thio-TOPO vector and transformed into Escherichia coli DH10B competent cells with the trp36-bearing plasmid for protein expression. To evaluate the protein antigenicity, 16 canine serum samples were previously tested (by PCR and the commercial SNAP4Dx serological test). The results were in accordance with the SNAP4Dx test. Experiments using this recombinant protein as an antigen, targeting the development of a serologic test based on ELISA methodology, are the next step to produce a reliable, affordable and useful diagnostic tool for CME in Brazil.Ehrlichia canis é o principal agente etiológico da erliquiose monocítica canina (EMC), uma doença infecciosa canina globalmente dispersa. No Brasil, a EMC é considerada endêmica, e a infecção pode atingir 65% em cães em alguns estados. O diagnóstico de erliquiose é importante para fins de tratamento e epidemiológicos. A proteína TRP36 de E. canis leva a uma resposta humoral com produção de anticorpos em fase aguda, encontrada durante o curso da doença. O objetivo deste estudo foi obter a proteína TRP36 recombinante da amostra São Paulo de E. canis e avaliar seu potencial como ferramenta para o diagnóstico sorológico da CME. O isolado de E. canis São Paulo foi cultivado em células da linhagem DH82 e o DNA genômico foi obtido. O fragmento de DNA bacteriano que codifica toda a ORF de TRP36 foi clonado no vetor pBAD / Thio-TOPO e transformado em células competentes Escherichia coli DH10B, com o plasmídeo portador de trp36 para expressão de proteínas. Para avaliar a antigenicidade da proteína, 16 amostras de soro canino foram previamente analisadas (por PCR e teste sorológico comercial SNAP4Dx). Os resultados estavam de acordo com o teste SNAP4Dx. Os experimentos que utilizam essa proteína recombinante como antígeno, visando ao desenvolvimento de um teste sorológico baseado no ELISA, são o próximo passo para produzir um teste de diagnóstico confiável, acessível e útil para o diagnóstico da EMC no Brasil

    Intense genomic reorganization in the genus Oecomys (Rodentia, Sigmodontinae): Comparison between DNA barcoding and mapping of repetitive elements in three species of the Brazilian Amazon

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    Oecomys Thomas, 1906 is one of the most diverse and widely distributed genera within the tribe Oryzomyini. At least sixteen species in this genus have been described to date, but it is believed this genus contains undescribed species. Morphological, molecular and cytogenetic study has revealed an uncertain taxonomic status for several Oecomys species, suggesting the presence of a complex of species. The present work had the goal of contributing to the genetic characterization of the genus Oecomys in the Brazilian Amazon. Thirty specimens were collected from four locations in the Brazilian Amazon and three nominal species recognized: Oecomys auyantepui (Tate, 1939), O. bicolor (Tomes, 1860) and O. rutilus (Anthony, 1921). COI sequence analysis grouped O. auyantepui, O. bicolor and O. rutilus specimens into one, three and two clades, respectively, which is consistent with their geographic distribution. Cytogenetic data for O. auyantepui revealed the sympatric occurrence of two different diploid numbers, 2n=64/NFa=110 and 2n=66/NFa=114, suggesting polymorphism while O. bicolor exhibited 2n=80/NFa=142 and O. rutilus 2n=54/NFa=90. The distribution of constitutive heterochromatin followed a species-specific pattern. Interspecific variation was evident in the chromosomal location and number of 18S rDNA loci. However, not all loci showed signs of activity. All three species displayed a similar pattern for 5S rDNA, with only one pair carrying this locus. Interstitial telomeric sites were found only in O. auyantepui. The data presented in this work reinforce intra- and interspecific variations observed in the diploid number of Oecomys species and indicate that chromosomal rearrangements have led to the appearance of different diploid numbers and karyotypic formulas. © Renan Gabriel Gomes Júnior et al

    Taxonomic status and phylogenetic relationships of Marmosa agilis peruana Tate, 1931 (Didelphimorphia: Didelphidae), with comments on the morphological variation of Gracilinanus from central-western Brazil

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    The marsupials of the family Didelphidae went through profound taxonomic rearrangements in recent decades, mainly related to an increase in the number of specimens deposited in scientific collections and the inclusion of molecular data in systematic analyses, resulting in better resolved phylogenies and taxa delimitation. Analyses of a large series of the gracile mouse opossum Gracilinanus agilis, including types and complementary material, recovered specimens assignable to Marmosa agilis peruana Tate, 1931 as a monophyletic group that is diagnosable by unique morphological, morphometric and molecular datasets, meriting its recognition as a full species. Here we provide an emended diagnosis, description and comparisons with congeners for G. peruanus. The former species differs from the latter by the dull reddish dorsal pelage, smaller general size, position of the maxillary fenestrae, presence of accessory cusps in upper canines, and morphology of the alisphenoid tympanic process. It ranges from central Peru to central Bolivia and western Brazil in the states of Rondônia and northwestern Mato Grosso, where it occurs in sympatry with G. agilis. Many collecting localities lie in areas with high diversity of non-volant small mammals and accelerated deforestation processes, highlighting its importance in terms of biogeographic studies and conservation policies. © 2014 The Linnean Society of London

    The Munduruku marmoset: A new monkey species from southern Amazonia

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    Although the Atlantic Forest marmosets (Callithrix spp.) are among the best studied Neotropical primates, the Amazonian marmosets (Callibella humilis, Cebuella spp. and Mico spp.) are much less well-known. Even species diversity and distributions are yet to be properly determined because field data and materials currently available in scientific collections do not allow comprehensive taxonomic studies of Amazonian marmosets. From 2015 to 2018, we conducted 10 expeditions in key-areas within southern Amazonia where little or no information on marmosets was available. In one such region-the Tapajós-Jamanxim interfluve-we recorded marmosets with a distinctive pelage pigmentation pattern suggesting they could represent a new species. We tested this hypothesis using an integrative taxonomic framework that included phylogenomic data (ddRAD sequences), pelage pigmentation characters, and distribution records. We found that the marmosets of the northern Tapajós-Jamanxim interfluve have unique states in pelage pigmentation characters, form a clade (100% support) in our Bayesian and Maximum-Likelihood phylogenies, and occur in an area isolated from other taxa by rivers. The integration of these lines of evidence leads us to describe a new marmoset species in the genus Mico, named after the Munduruku Amerindians of the Tapajós-Jamanxim interfluve, southwest of Pará State, Brazil. Copyright © 2019 Costa-Araújo et al

    Current pretreatment technologies for the development of cellulosic ethanol and biorefineries

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    Lignocellulosic materials, such as forest, agriculture, and agroindustrial residues, are among the most important resources for biorefineries to provide fuels, chemicals, and materials in such a way to substitute for, at least in part, the role of petrochemistry in modern society. Most of these sustainable biorefinery products can be produced from plant polysaccharides (glucans, hemicelluloses, starch, and pectic materials) and lignin. In this scenario, cellulosic ethanol has been considered for decades as one of the most promising alternatives to mitigate fossil fuel dependence and carbon dioxide accumulation in the atmosphere. However, a pretreatment method is required to overcome the physical and chemical barriers that exist in the lignin–carbohydrate composite and to render most, if not all, of the plant cell wall components easily available for conversion into valuable products, including the fuel ethanol. Hence, pretreatment is a key step for an economically viable biorefinery. Successful pretreatment method must lead to partial or total separation of the lignocellulosic components, increasing the accessibility of holocellulose to enzymatic hydrolysis with the least inhibitory compounds being released for subsequent steps of enzymatic hydrolysis and fermentation. Each pretreatment technology has a different specificity against both carbohydrates and lignin and may or may not be efficient for different types of biomasses. Furthermore, it is also desirable to develop pretreatment methods with chemicals that are greener and effluent streams that have a lower impact on the environment. This paper provides an overview of the most important pretreatment methods available, including those that are based on the use of green solvents (supercritical fluids and ionic liquids)

    Current Pretreatment Technologies for the Development of Cellulosic Ethanol and Biorefineries

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