No abstract

The Pantanal is under the influence of the Paraguay River flood regime is considered to be one of the largest wetlands of the world, and has rich biodiversity, including fishes. Until now, the identification of fish species in this biome has only considered the morphological characteristics of individuals, and the present work aimed to identify the fish species of the Pantanal region through the DNA barcode methodology for investigating the biodiversity in this region. The genetic analysis of 638 samples via the GMYC approach identified 137 operational taxonomic units (OTUs) belonging to 127 species that have previously been described according to their morphological characteristics. Data suggest that 10 cases of morphospecies (Eigenmannia trileneata, E. virescens, Pimelodella gracilis, Brachyhypopomus pinnicaudatus, Brachyhypopomus sp., Ancistrus sp., Hyphessobrycon eques, Jupiaba acanthogaster, and Serrapinnus calliurus) represent complexes of cryptic species, and the number of species described in the Pantanal region has thus potentially been underestimated.

The combination of cytogenetic and molecular data with those traditionally obtained in areas like systematics and taxonomy created interesting perspectives for the analysis of natural populations under different aspects. In this context, this study aimed to evaluate the genetic differentiation among populations of the genus Hemiodontichthys Bleeker, 1862, through combined genetic techniques and included the analysis of populations sampled in the Araguaia River, Guamá River, Madeira River and two populations from the Purus River. Hemiodontichthys samples from the two localities in Purus River were also karyotyped in order to address the degree of chromosomal variation between populations. Through GMYC analysis of the COI tree, the patterns of genetic variation among local populations revealed to be higher than the ones found among distinct species from other genera of the subfamily Loricariinae, suggesting the existence of probable four cryptic species in this genus. The possible existence of a species complex in the genus is corroborated by the different cytogenetic patterns between Hemiodontichthys sp. 1 and sp. 2, revealing the necessity of a deep taxonomic review of the group.

No abstract

The tiger shark (Galeocerdo cuvier) has a global distribution in tropical and warm temperate seas, and it is caught in numerous fisheries worldwide, mainly as bycatch. It is currently assessed as near threatened by the International Union for Conservation of Nature (IUCN) Red List. In this study, we identified nine microsatellite loci through next generation sequencing (454 pyrosequencing) using 29 samples from the western Atlantic. The genetic diversity of these loci were assessed and revealed a total of 48 alleles ranging from 3 to 7 alleles per locus (average of 5.3 alleles). Cross-species amplification was successful at most loci for other species such as Carcharhinus longimanus, C. acronotus and Alopias superciliosus. Given the potential applicability of genetic markers for biological conservation, these data may contribute to the population assessment of this and other species of sharks worldwide.

The biological invasion process is widely debated topic, as the population depletion of some species and the extinction of others are related to this process. To accelerate the identification of species and to detect non-native forms, new tools are being developed, such as those based on genetic markers. This study aimed to use Barcode DNA methodology to identify fish species that had translocated between the Parana and Paraguay River Basins. Based on a database of two studies that were conducted in these regions, 289 sequences of Cytochrome Oxidase C subunit 1 (COI) were used for General Mixed Youle Coalecent (GMYC) analysis, including 29 morphospecies that were sampled in both river basins. As a result, we observed that while some morphospecies have low variation, demonstrating a recent occupation of the basins, other morphospecies probably represent species complexes. A third of the morphospecies had well-defined lineages but not enough to be treated as different Molecular Operational Taxonomic Units (MOTUs). These results demonstrate that human interventions possibly participated in the distribution of some lineages. However, biogeographical historical processes are also important for the morphospecies distribution. The data suggest that the number of species that are present in these two basins is underestimated and that human actions can irreversibly affect the natural history of the species in these regions.

Species identification is a difficult task, ranging from the definition of the species concept itself to the definition of the threshold for speciation. DNA Barcode technology uses a fragment of the Cytochrome Oxidase I (COI) gene as a molecular tool that many studies have already validated as a tool for species identification. DNA barcode sequences for COI were generated and analyzed from 805 specimens. The General Mixed Yule Coalescent (GMYC) analysis recognized 99 independent evolution units, and the Barcode Index Numbers (BIN) approach pointed to the existence of 104 BINs (interpreted as distinct species). By cross-tabulating the results of all approaches, we identified 109 Molecular Operational Taxonomic Units (MOTU) by at least one methodology. In most cases (89 MOTUs), the genetic approaches are in agreement with morphological identification, and the discrepant results of MOTUs are in the complex groups, which have many morphological similarities but may represent species complexes.

ResumoAspergillus carbonarius é um potente produtor de ocratoxina A, uma toxina que apresenta efeitos nefrotóxico e carcinogênico. O conhecimento de genes envolvidos em sua biossíntese pode contribuir para o desenvolvimento de medidas de controle. O método de transformação genética mediado por Agrobacterium tumefaciens tem sido demonstrado como uma importante ferramenta para a obtenção de mutantes insercionais visando à caracterização de novos genes. O objetivo deste trabalho foi adequar o método de transformação genética via A. tumefaciens para a linhagem ITAL187 de A. carbonarius e obter mutantes alterados para a produção de ocratoxina A. Conídios foram transformados para resistência a higromicina B usando a linhagem AGL-1 de A. tumefaciens. A freqüência média de transformação foi de 20,04 transformantes por 10 5 conídios-alvo. A prova física da transformação foi obtida pela detecção do gene hph por PCR e Southern Blot. Esta última demonstrou que a integração do DNA exógeno ocorreu de forma aleatória no genoma fúngico. Dentre 238 transformantes, 12 (5,042%) mostraram variações morfológicas. Três mutantes (T44, T47 e T188) com significativa redução e dois mutantes (T238 e T162) com aumento da capacidade de produção de ocratoxina A foram obtidos. A identificação dos genes nocauteados contribuirá para a compreensão da biossíntese desta toxina. Palavras-chave: Aspergillus carbonarius. Ocratoxina A. Agrobacterium tumefaciens. Transformação genética. Mutantes insercionais. AbstractAspergillus carbonarius is a potent ochratoxin A producer, a mycotoxin that has nephrotoxic and carcinogenic effects. The knowledge of genes involved in biosynthesis of this toxin may be useful for the development of detection and control methods. The Agrobacterium tumefaciens-mediated transformation method has been demonstrated as a powerful tool to obtain insertional mutants for the characterization of new genes. The aim of this work was to adapt the A. tumefaciens-mediated transformation method for ITAL187 strain of A. carbonarius and to obtain transformants with alteration in ochratoxin A production. Conidia were transformed to hygromicin B resistance using AGL-1 strain of A. tumefaciens. The transformation frequency was 20,04 transformants per 10 5 target conidia. The transformation evidence was obtained by PCR and Southern Blot analysis. The last one showed us that 1 Bolsista PIBIC/CNPq/UEL -UEL