Effectiveness of ultrasonic activation over glycolic acid on microhardness, cohesive strength, flexural strength, and fracture resistance of the root dentin.

OBJECTIVES: The aim of this study was to evaluate the effectiveness of ultrasonic activation (US) over glycolic acid on microhardness, cohesive strength, flexural strength, and fracture resistance of root dentin, comparing with conventional final irrigation protocols. METHODS: Samples were obtained from 140 extracted bovine teeth and distributed into four test groups: microhardness (50 teeth), cohesive strength (15 teeth), flexural strength (15 teeth), and fracture resistance (60 teeth). In all four tests, specimens were subdivided into five groups, according to final irrigation protocols: G1: distilled water (DW); G2: 17% ethylenediaminetetraacetic acid (EDTA); G3: 17% glycolic acid (GA); G4: 17% EDTA + US; and G5: 17% GA + US. The duration time of each protocol was set in 1 min. After irrigation protocols, the Vickers tester was used to evaluate microhardness and the universal testing machine was used to evaluate the cohesive strength, flexural strength, and fracture resistance of the root dentin. One-way ANOVA test and the Tukey HSD were used for multiple comparison tests in all evaluations (α = 5%). RESULTS: In general, groups 2 (EDTA), 4 (EDTA + US), and 5 (GA + US) promoted the highest reduction of microhardness, being statistically different from other groups (p < 0.05). Cohesive strength, flexural strength, and fracture resistance data revealed that no differences between groups were observed (p > 0.05). CONCLUSIONS: The association of GA and US results in microhardness reduction, with no influence on cohesive strength, flexural strength, and fracture resistance of the root dentin. CLINICAL RELEVANCE: The use of US over GA has no influence on some mechanical properties of root dentin.

The use of an integrative approach to improve accuracy of species identification and detection of new species in studies of stream fish diversity.

In this study, we made an inventory of the stream and headwater ichthyofauna of the left bank of the Itaipu Dam Reservoir, located in the lower part of the Upper Paraná River basin, using an integrative approach of molecular and morphological data. The area is located in the western portion of the Paraná state in Brazil, in an area of about 8,000 km2 highly impacted by deforestation and intensive agriculture. For taxonomic identification of species, we used an identification key combined with the DNA barcoding approach. We found 48 species belonging to six orders, 13 families, and 37 genera. The Siluriformes and Characiformes were the most representative orders (75%) and the Characidae was the most representative family (20.8%). Nine species prevailed in this region, making up to 86% of all specimens collected. The integrative approach proved to be useful by allowing the unambiguous identification of all species, including those cases in which morphological characters were not conclusive for species identification, cases of cryptic species, and species with high morphological plasticity. In addition, the integrative approach highlighted six to 13 new putative species depending on the approach considered. Our study provides a relevant contribution to the knowledge of fish diversity in a poorly studied area of the Paraná River basin. We showed that the use of an integrative approach in inventory studies improves species identification and the discovery of new, cryptic, and overlooked species, being a powerful and necessary tool to quantify biodiversity.

11p15 Epimutations in Pediatric Embryonic Tumors: Insights from a Methylome Analysis.

Embryonic tumors share few recurrent mutations, suggesting that other mechanisms, such as aberrant DNA methylation, play a prominent role in their development. The loss of imprinting (LOI) at the chromosome region 11p15 is the germline alteration behind Beckwith-Wiedemann syndrome that results in an increased risk of developing several embryonic tumors. This study analyzed the methylome, using EPIC Beadchip arrays from 99 sporadic embryonic tumors. Among these tumors, 46.5% and 14.6% presented alterations at imprinted control regions (ICRs) 1 and 2, respectively. Based on the methylation levels of ICR1 and ICR2, four clusters formed with distinct methylation patterns, mostly for medulloblastomas (ICR1 loss of methylation (LOM)), Wilms tumors, and hepatoblastomas (ICR1 gain of methylation (GOM), with or without ICR2 LOM). To validate the results, the methylation status of 29 cases was assessed with MS-MLPA, and a high level of agreement was found between both methodologies: 93% for ICR1 and 79% for ICR2. The MS-MLPA results indicate that 15 (51.7%) had ICR1 GOM and 11 (37.9%) had ICR2 LOM. To further validate our findings, the ICR1 methylation status was characterized via digital PCR (dPCR) in cell-free DNA (cfDNA) extracted from peripheral blood. At diagnosis, we detected alterations in the methylation levels of ICR1 in 62% of the cases, with an agreement of 76% between the tumor tissue (MS-MLPA) and cfDNA methods. Among the disagreements, the dPCR was able to detect ICR1 methylation level changes presented at heterogeneous levels in the tumor tissue, which were detected only in the methylome analysis. This study highlights the prevalence of 11p15 methylation status in sporadic embryonic tumors, with differences relating to methylation levels (gain or loss), location (ICR1 or ICR2), and tumor types (medulloblastomas, Wilms tumors, and hepatoblastomas).

Somatic Copy Number Alteration in Circulating Tumor DNA for Monitoring of Pediatric Patients with Cancer.

Pediatric tumors share few recurrent mutations and are instead characterized by copy number alterations (CNAs). The cell-free DNA (cfDNA) is a prominent source for the detection of cancer-specific biomarkers in plasma. We profiled CNAs in the tumor tissues for further evaluation of alterations in 1q, MYCN and 17p in the circulating tumor DNA (ctDNA) in the peripheral blood at diagnosis and follow-up using digital PCR. We report that among the different kinds of tumors (neuroblastoma, Wilms tumor, Ewing sarcoma, rhabdomyosarcoma, leiomyosarcoma, osteosarcoma and benign teratoma), neuroblastoma presented the greatest amount of cfDNA, in correlation with tumor volume. Considering all tumors, cfDNA levels correlated with tumor stage, metastasis at diagnosis and metastasis developed during therapy. In the tumor tissue, at least one CNA (at CRABP2, TP53, surrogate markers for 1q and 17p, respectively, and MYCN) was observed in 89% of patients. At diagnosis, CNAs levels were concordant between tumor and ctDNA in 56% of the cases, and for the remaining 44%, 91.4% of the CNAs were present only in cfDNA and 8.6% only in the tumor. Within the cfDNA, we observed that 46% and 23% of the patients had MYCN and 1q gain, respectively. The use of specific CNAs as targets for liquid biopsy in pediatric patients with cancer can improve diagnosis and should be considered for monitoring of the disease response.

Species delimitation of neotropical Characins (Stevardiinae): Implications for taxonomy of complex groups.

Accurate species delimitation is crucial for studies of phylogeny, phylogeography, ecology, conservation and biogeography. The limits of species and genera in the Characidae family are controversial due to its uncertain phylogenetic relationships, high level of morphological homoplasy and the use of ambiguous morphological characters for descriptions. Here we establish species boundaries for Bryconamericus, Hemibrycon, Knodus and Eretmobrycon (Stevardiinae: Characidae), previously diagnosed with morphology, using three different barcoding approaches (GMYC, PTP, ABGD). Results revealed that species delimitation was successful by the use of a single-gene approach and by following a workflow in the context of integrative taxonomy, making evident problems and mistakes in the cataloging of Characidae species. Hence, it was possible to infer boundaries at genus level for clusters in the trees (GMYC and PTP) and automatic partitions (ABGD) which were consistent with some of recent taxonomic changes proposed in Characidae. We found that discordance cases between methods were linked to limitations of the methods and associated to putative species cluster closely related, some historically problematic in their diagnosis and identification. Furthermore, we suggested taxonomic changes and possibly new species, revealing a high degree of hidden diversity. Finally, we propose a workflow as a fast, accurate and objective way to delimit species from mitochondrial DNA sequences and to help clarify the classification of this group.

DNA barcoding techniques used to identify the shared ichthyofauna between the Pantanal floodplain and Upper Parana River.

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.

Effects of acute alcohol intoxication on visuospatial attention.

The aim of the present study was to examine the effects of acute alcohol intoxication on the spatial distribution of visual attention measured with simple reaction times (RTs) to targets presented over an extended region of the visual field. Control (n=10) and alcohol groups (n=14) were tested with the same protocol. Participants were tested in two different conditions; in Experiment I, participants were instructed to direct their visual attention to the centre, while in Experiment II they were asked to orient their attention covertly to both right and left, but not to the centre. Throughout participants were required to fixate a small cross in the centre of the computer screen. In the alcohol group, participants received an alcohol dose of 0.4 g/kg so as to produce a blood alcohol concentration (BAC) in the range of 0.08% during the experiments. The spatial distribution of RTs was analysed graphically with geostatistical methods and statistically through analysis of variance of particular regions of the visual field. Results showed that controls were able to direct their attention tightly towards the centre (Expt I) and also to divide attention (Expt II) to the right and left. Participants in the alcohol group fixed their attention more diffusely in the centre (Expt I) and were unable to disengage attention from the centre in Experiment II. We conclude that acute alcohol intoxication impairs the ability to dissociate attention from gaze.

Adoecimento psíquico, assimetrias de gênero na Medicina e necessidade de intervenção: uma revisão de literatura / Mental illness, asymmetries between genders in the medical profession, and the need for intervention: a literature review / Enfermarse psíquicamente, asimetrías de género en la medicina y necesidad de intervención: una revisión de la literatura

A Medicina possui um notório impacto adoecedor sobre seus profissionais. Isso é acertado se comparando as altas prevalências de depressão e suicídio na população médica com aquelas relativas à população geral. Entretanto, observadas as assimetrias de gênero existentes nas relações humanas, emerge a necessidade da busca para a elucidação de disparidades de gênero no interior dos âmbitos profissionais e acadêmicos da Medicina, além de propostas capazes de alterar aspectos nocivos da carreira. Para tanto, realizou-se uma revisão da literatura pela análise de trinta artigos publicados nas plataformas PubMed/Medline e Google Scholar em português, inglês e francês, nos últimos dez anos. Os achados permitiram acertar uma vulnerabilidade do gênero feminino, uma vez imerso no âmbito médico, traduzida em maior crescimento de índices de depressão e suicídio. Foram apontadas propostas de alteração dessa realidade por meio de estratégias de caracteres preventivo e interventivo. (AU)

The medical profession has notorious health impacts on professionals, shown by the proportionately higher prevalence of depression and suicide among doctors than in the general population. However, given the asymmetries between genders in human relations, there is the need to elucidate gender disparities within the medical profession and Academia, and develop proposals capable of minimizing the harmful aspects of the career. To this end, we conducted a literature review that included the analysis of thirty articles published in Portuguese, English and French in PubMed/Medline and Google Scholar over the last ten years. The findings confirm the vulnerability of female doctors, manifested in increased rates of depression and suicide. We propose measures to improve this situation through prevention and intervention strategies. (AU)

La Medicina tiene un notorio impacto como causador de enfermedades en sus profesionales. Eso es acertado si se comparan las altas prevalencias para depresión y suicidio en la población médica con las relativas a la población en general. No obstante, observadas las asimetrías de género existentes en las relaciones humanas, surge la necesidad de la búsqueda para elucidar disparidades de género en el interior de los ámbitos profesionales y académicos de la Medicina, además de propuestas capaces de alterar aspectos nocivos de la carrera. Para ello, se realizó una revisión de la literatura, mediante análisis de treinta artículos, publicados en las plataformas PubMed/Medline y Google Scholar en portugués, inglés y francés, en los últimos diez años. Los hallazgos permitieron acertar una vulnerabilidad del género femenino, una vez inmerso en el ámbito médico, traducida en un mayor crecimiento en índices de depresión y suicidio. Se señalaron propuestas de alteración de esta realidad por medio de estrategias con carácter de prevención e intervención. (AU)

Fish fauna from a fragmented river in the Atlantic Forest / Fauna de peixes de um rio fragmentado na Mata Atlântica

Abstract: This study sought to identify the ichthyofauna composition of the Muzambinho River, an upland tributary of the Paraná River. We also investigate whether waterfalls in the region can serve as barriers to the dispersal of fish species. For this purpose, collections were carried out at 34 points on the Muzambinho River using different techniques. In all, 37 species were recorded, some of which were endemic, and the majority were native. Among these species, some are predominant in degraded places and can be used as bioindicators. The results also demonstrate zonation in the ichthyofauna composition in Muzambinho that segregates the fauna into three sessions separated by waterfalls: Lower Muzambinho, Upper Muzambinho, and Sao Domingos. We conclude that, for the ideal preservation of the ichthyofauna of the Muzambinho River, it is necessary to preserve its sections independently, which would guarantee the maintenance of naturally isolated strains.

Resumo: Este estudo buscou identificar a composição da ictiofauna do rio Muzambinho, um tributário de terras altas do Rio Paraná. Também buscamos investigar se as cachoeiras da região podem servir de barreiras para dispersão de espécies de peixes. Para isso, foram realizadas coletas em 34 pontos do Rio Muzambinho, com diferentes técnicas. Ao todo foram registradas 37 espécies de peixes, sendo algumas endêmicas e a maioria nativa. Dentre essas espécies algumas são predominantes em locais degradados e podem ser usadas como bioindicadores. Os resultados também demonstram que há uma zonação na composição ictiofaunística no Muzambinho que segrega a fauna em três sessões separadas por cachoeiras, Baixo Muzambinho, Alto Muzambinho e São Domingos. Concluímos que para a ideal preservação da ictiofauna do rio Muzambinho é necessária a preservação independente de suas sessões o que garantiria a manutenção de linhagens naturalmente isoladas.

Epidemiology of Spinal cord Injury in references trauma center in Curitiba (Paraná, Brazil) / Epidemiologia do trauma raquimedular (TRM) em hospitais-referência de trauma na cidade de Curitiba (Paraná, Brasil) / Epidemiología del trauma raquimedular (TRM) en hospitales referencia de trauma en la ciudad de Curitiba (Paraná, Brazil)

ABSTRACT Objective: To outline the clinical-epidemiological profile of patients who were victims of SCT, to identify the main trauma mechanisms for this injury and its outcome. Methods: Retrospective cross-sectional study, in which the epidemiological data, computed tomography reports and medical records of patients with fractures identified in their examinations at trauma reference hospitals in Curitiba-PR, in 2018, were analyzed. Results: 705 patients were studied. There was a male prevalence (64%), the most affected age group was 21 to 30 years old (18%), the mean age was 48.23 years, the mean female age being approximately 10 years higher. The main mechanisms were traffic accidents (34%), falls from a higher level (29%) and falls from the same level (25%). The most affected segment was the lumbar with 46% of cases. The incidence of surgical treatment was 15%, of spinal cord injury was 5%, and death was the outcome in less than 3% of cases. Conclusions: The profile of the patient victim of SCT in 2018 in Curitiba-PR was that of a young man, victim of a traffic accident with thoracolumbar involvement without spinal cord injury, under conservative treatment.Level of evidence II; Retrospective Study.

RESUMO Objetivo: Traçar o perfil clínico-epidemiológico dos pacientes vítimas de TRM, identificar os principais mecanismos de trauma para esta lesão e seu desfecho. Métodos: Estudo transversal retrospectivo, em que foram analisados dados epidemiológicos, laudos de tomografia computadorizada e prontuários dos pacientes que apresentaram fratura em seus exames, nos hospitais-referência de trauma em Curitiba-PR, no ano de 2018. Resultados: Dos 705 pacientes estudados, houve prevalência masculina (64%); a faixa-etária mais acometida foi de 21 a 30 anos (18%); a idade média geral foi de 48,23 anos, sendo a média feminina aproximadamente 10 anos mais alta. Os principais mecanismos foram acidente de trânsito (34%), queda de nível (29%) e queda de mesmo nível (25%). O segmento mais acometido foi lombar com 46% dos casos; tratamento cirúrgico teve incidência de 15%, lesão medular de 5% e óbito foi desfecho em menos de 3% dos casos. Conclusões: O perfil do paciente vítima de TRM no ano de 2018 em Curitiba-PR foi de um homem jovem, vítima de acidente de trânsito com acometimento toracolombar sem lesão medular, sob tratamento conservador. Nível de evidência II; Estudo Retrospectivo.

RESUMEN Objetivo: Trazar el perfil clínico-epidemiológico de los pacientes víctimas de TRM, identificar los principales mecanismos de trauma para esta lesión y su resultado. Métodos: Estudio transversal retrospectivo, en el que fueron analizados datos epidemiológicos, laudos de tomografía computarizada e historiales médicos de los pacientes que presentaron fractura en sus exámenes, en los hospitales referencia de trauma, en Curitiba-PR, en el año 2018. Resultados: De los 705 pacientes estudiados, hubo prevalencia masculina (64%); el grupo de edad más acometido fue de 21 a 30 años (18%); la edad promedio general fue de 48,23 años, siendo el promedio femenino aproximadamente 10 años más alto. Los principales mecanismos fueron accidente de tránsito (34%), caída de nivel (29%) y caída del mismo nivel (25%). El segmento más acometido fue el lumbar con 46% de los casos; el tratamiento quirúrgico tuvo incidencia del 15%, la lesión medular de 5% y la muerte fue resultado en menos del 3% de los casos. Conclusiones: El perfil del paciente víctima de TRM en 2018 en Curitiba-PR fue de un hombre joven, víctima de accidente de tránsito con acometimiento toracolumbar sin lesión medular, bajo tratamiento conservador.Nivel de evidencia II; Estudio retrospectivo.

Laparoscopic Transposition of Lower Pole Crossing Vessels (Vascular Hitch) in Children with Pelviureteric Junction Obstruction: How to Be Sure of the Success of the Procedure?

BACKGROUND: To report a series of children with pelviureteric junction obstruction (PUJO) due to lower polar crossing vessels who underwent laparoscopic vascular transposition. In order to confirm the relief of the obstruction and avoid unnecessary additional procedures, we suggest performing an intraoperative measure of the ureteral opening pressure. PATIENTS AND METHODS: From January 2007 and January 2014, 11 children underwent laparoscopy to treat well-documented PUJO by polar vessels. In the first 7 cases, children underwent a careful dissection of the polar vessels that were transposed cranially in the pelvis. In the last 4 cases, a percutaneous needle was inserted into the renal pelvis, and the ureteral opening pressure was obtained intraoperatively, before and after the vascular hitch procedure, in 3 cases. No vascular relocation was necessary except in 1 case with a polar vessel unrelated to the obstruction. RESULTS: The laparoscopic procedure was feasible in all cases. Median operative time was 90 minutes without intraoperative complications. In the last 3 cases, a decrease in the renal pelvic pressure was demonstrated just after releasing the ureter from the polar vessels, confirming the extrinsic obstruction. In 1 case, the intraoperative pelvic pressure measurement showed that there was no vascular compression but that obstruction was due to renal rotation. During follow-up (range, 12-96 months) all patients reported resolution of their symptoms, nine children showed a decrease in the hydronephrosis grade, and all but one with poor function had improved drainage on diuretic renography. CONCLUSIONS: Intraoperative measurement of ureteral opening pressure may help to confirm that the vascular hitch procedure has relieved the pelvic obstruction, precluding the need for dismembered procedures. We believe that in some doubtful cases, with the addition of intraoperative pelvic pressure measurement, vascular hitch may be considered a safe procedure to treat selected cases of PUJO in children.

Genetic structure and historical diversification of catfish Brachyplatystoma platynemum (Siluriformes: Pimelodidae) in the Amazon basin with implications for its conservation.

Brachyplatystoma platynemum is a catfish species widely distributed in the Amazon basin. Despite being considered of little commercial interest, the decline in other fish populations has contributed to the increase in the catches of this species. The structure, population genetic variability, and evolutionary process that have driven the diversification of this species are presently unknown. Considering that, in order to better understand the genetic structure of this species, we analyzed individuals from seven locations of the Amazon basin using eight molecular markers: control region and cytochrome b mtDNA sequences, and a set of six nuclear microsatellite loci. The results show high levels of haplotype diversity and point to the occurrence of two structured populations (Amazon River and the Madeira River) with high values for F ST. Divergence time estimates based on mtDNA indicated that these populations diverged about 1.0 Mya (0.2-2.5 Mya 95% HPD) using cytochrome b and 1.4 Mya (0.2-2.7 Mya 95% HPD) using control region. During that time, the influence of climate changes and hydrological events such as sea level oscillations and drainage isolation as a result of geological processes in the Pleistocene may have contributed to the current structure of B. platynemum populations, as well as of differences in water chemistry in Madeira River. The strong genetic structure and the time of genetic divergence estimated for the groups may indicate the existence of strong structure populations of B. platynemum in the Amazon basin.

DNA barcodes identify marine fishes of São Paulo State, Brazil.

Anthropogenic impacts are an increasing threat to the diversity of fishes, especially in areas around large urban centres, and many effective conservation actions depend on accurate species identification. Considering the utility of DNA barcoding as a global system for species identification and discovery, this study aims to assemble a DNA barcode reference sequence library for marine fishes from the coastal region of São Paulo State, Brazil. The standard 652 bp 'barcode' fragment of the cytochrome c oxidase subunit I (COI) gene was PCR amplified and bidirectionally sequenced from 678 individuals belonging to 135 species. A neighbour-joining analysis revealed that this approach can unambiguously discriminate 97% of the species surveyed. Most species exhibited low intraspecific genetic distances (0.31%), about 43-fold less than the distance among species within a genus. Four species showed higher intraspecific divergences ranging from 2.2% to 7.6%, suggesting overlooked diversity. Notably, just one species-pair exhibited barcode divergences of <1%. This library is a first step to better know the molecular diversity of marine fish species from São Paulo, providing a basis for further studies of this fauna - extending the ability to identify these species from all life stages and even fragmentary remains, setting the stage for a better understanding of interactions among species, calibrating the estimations about species composition and richness in an ecosystem, and providing tools for authenticating bioproducts and monitoring illegal species exploitation.

Role of the medial olivocochlear system among children with ADHD.

UNLABELLED: Attention deficit hyperactivity disorder (ADHD) patients show, as one of the main symptoms, an attentional impairment. Selective attention in the hearing process is the ability to understand speech in a noisy environment, which can be evaluated by several methods. One of the main approaches is the functioning of the Medial Olivocochlear Efferent System, which can be accessed by Transient-Evoked Otoacoustic Emissions (TOAE). OBJECTIVE: This study aimed at evaluating the suppression effect of contralateral noise on TOAE in ADHD (study group) and normal subjects (control group). STUDY DESIGN: Case-control study. MATERIAL AND METHODS: A study with 20 children distributed in two, age- and gender-matched groups. RESULTS: No differences were found in TOAE responses between the two groups, with and without noise. CONCLUSIONS: We conclude that there were no functional differences in the Medial Olivocochlear Efferent System in the two groups analyzed.

Genetic variability of two populations of Pseudoplatystoma reticulatum from the Upper Paraguay River Basin.

Catfishes of the genus Pseudoplatystoma are very important species due to both their high commercial value and their ecological role as voracious predators. They undertake lengthy migratory movements during their life-cycle, this including reproductive migration which occurs from October to December in the rainy season. In the present study, seven microsatellite loci were analyzed to access genetic variability in two samples of P. reticulatum from the Upper Paraguay Basin. The loci were highly polymorphic (mean = 7.28). According to all analysis, the two samples of P. reticulatum revealed pronounced genetic differentiation. F(st) value was 0.2290, R(st) value 0.1067 and AMOVA 22.90% (F(st) ) and 10.67% (R(st) ), all being highly significant (p < 0.001). The division of the fishes into two groups was confirmed by microsatellite multi-locus Bayesian assignment testing. The results obtained present evidence of genetic structuring in a P. reticulatum population.

DNA barcode of parodontidae species from the La Plata river basin - applying new data to clarify taxonomic problems

In the past years, DNA barcoding has emerged as a quick, accurate and efficient tool to identify species. Considering the difficulty in identifying some Parodontidae species from the La Plata basin and the absence of molecular data for the group, we aimed to test the effectiveness of DNA barcoding and discuss the importance of using different approaches to solve taxonomic problems. Eight species were analyzed with partial sequences of Cytochrome c oxidase I. The mean intraspecific K2P genetic distance was 0.04% compared to 4.2% for mean interspecific K2P genetic distance. The analyses of distance showed two pairs of species with K2P genetic divergence lower than 2%, but enough to separate these species. Apareiodon sp. and A. ibitiensis, considered as the same species by some authors, showed 4.2% genetic divergence, reinforcing their are different species. Samples of A. affinis from the Uruguay and Paraguay rivers presented 0.3% genetic divergence, indicating a close relationship between them. However, these samples diverged 6.1% from the samples of the upper Paraná River, indicating that the latter represents a potentially new species. The results showed the effectiveness of the DNA barcoding method in identifying the analyzed species, which, together with the morphological and cytogenetic available data, help species identification.

Nos últimos anos o DNA barcoding surgiu como uma ferramenta rápida, precisa e eficiente para identificar espécies. Considerando a dificuldade na identificação de algumas espécies de Parodontidae da bacia do rio da Prata e da ausência de dados moleculares para o grupo, testamos a eficácia do código de barras de DNA e discutimos a importância do uso de diferentes abordagens para resolver problemas taxonômicos. Oito espécies foram analisadas com sequencias parciais do gene citocromo c oxidase I. A distância genética média K2P intraespecífica foi de 0,04% comparado com 4,2% para distância genética média K2P interespecífica. As análises de distância mostraram dois pares de espécies com divergência genética K2P inferior a 2%, mas o suficiente para separar estas espécies. Apareiodon sp. e A. ibitiensis, consideradas a mesma espécie por alguns autores, mostraram 4,2% de divergência genética, confirmando serem espécies diferentes. Amostras de A. affinis dos rios Uruguai e Paraguai apresentaram 0,3% de divergência genética, indicando um maior grau de relação entre elas, no entanto, esses exemplares divergiram em 6,1% em relação aos exemplares do alto rio Paraná, o que indica que estes últimos representam uma espécie potencialmente nova. Os resultados mostraram a eficácia do método de DNA barcoding na identificação das espécies analisadas, os quais, em conjunto com os dados morfológicos e citogenéticos disponíveis auxiliam na identificação inequívoca das espécies.

Cytogenetic and molecular markers reveal the complexity of the genus Piabina Reinhardt, 1867 (Characiformes: Characidae)

Cytogenetic and molecular analyses were carried out in fish representative of the genus Piabina. This study specifically involved the species P. argentea and P. anhembi collected from areas of the Paranapanema and Tietê River basins, Brazil. Our findings suggest that fish classified as Piabina argentea in the Paranapanema and Tietê Rivers may represent more than one species. The samples analyzed differed by cytogenetic particularities and molecular analyses using partial sequences of the genes COI and CytB as genetic markers revealed three distinct groups of P. argentea with genetic distances sufficient to support the conclusion that the three samples analyzed are three distinct taxonomic units.

Foram realizadas análises citogenéticas e moleculares em representantes do gênero Piabina. O estudo envolveu especificamente as espécies P. argentea e P. anhembi coletadas nas áreas das bacias hidrográficas dos rios Paranapanema e Tietê (Brasil). Os dados sugerem que a espécie P. argentea coletada nas bacias dos rios Paranapanema e Tietê podem representar mais de uma espécie. As amostras analisadas diferem por particularidades citogenéticas e nas análises moleculares utilizando-se sequências parciais dos genes COI e CytB, revelando três grupos distintos de P. argentea com distâncias genéticas suficientes para sustentar a conclusão de que as três amostras analisadas são unidades taxonômicas distintas.