Considerações geológicas e paisagísticas sobre o habitat de Leptodactylus fuscus (Amphibia, Anura)

Como parte de um estudo mais amplo, o qual inclui análises citogenéticas e moleculares da espécie Leptodactylus fuscus (Schneider, 1799), estamos apresentando, neste trabalho, como os fatores geológicos e paisagísticos dos ambientes ocupados pela referida espécie na região do Campus Universitário do Guamá, Belém, Estado do Pará, interferem em seu processo evolutivo

PESQUISA QUANTITATIVA E EDUCAÇÃO: DESAFIOS E POTENCIALIDADES

Developing large-scale research in education requires access to a great amount of data, which involves the participation of many collaborators. In addition to considering Brazilian geographical dimension and its regional particularities, it is necessary to have an efficient logistics for the successful development of studies. This paper shares and reflects on a number of quantitative and large-scale research in the context of science teaching pointing out theoretical-methodological aspects, some challenges and the investigation possibilities to obtain nationwide representative data. The results demonstrate that collaborative work should be part of research providing the integration and discussion among all those involved in the research. When designing research with these characteristics it is necessary to consider the particularities of the schools and universities so that all institutions interact and perform as trainers during data generation and treatment.  A realização de pesquisas em larga escala na área da educação requer acesso a uma grande produção de dados, que envolve a participação de muitos sujeitos colaboradores. Considerando-se as dimensões geográficas do Brasil, com suas particularidades regionais, é imprescindível uma logística eficiente para a execução exitosa do estudo. Pensando nisso, o presente trabalho tem como objetivo apresentar algumas reflexões sobre as experiências com pesquisas de cunho quantitativo e de larga escala no âmbito do ensino de ciências, caracterizando aspectos teórico-metodológicos, alguns desafios e as possibilidades de investigação ao se obter dados de representatividade nacional. Os resultados apontam que, ao delinear uma pesquisa com essas características, o trabalho colaborativo deve se fazer presente, a fim de possibilitar a integração e discussão entre todos os sujeitos envolvidos na pesquisa. Além disso, é preciso considerar as especificidades das escolas e da universidade, de modo que ambas as instituições dialoguem e ocupem o lugar de formadoras durante o processo de obtenção e tratamento dos dados da investigação.La realización de investigaciones a gran escala en el área de la educación requiere el acceso a una gran producción de datos. También, implica la participación de muchos colaboradores y, además, teniendo en cuenta las dimensiones geográficas de Brasil, con sus particularidades regionales, exige una logística eficiente para la implementación exitosa del estudio. El presente trabajo tiene por objetivo presentar algunas reflexiones sobre las experiencias con la investigación cuantitativa y de gran escala en el campo de la enseñanza de ciencias, caracterizando aspectos teórico-metodológicos, algunos retos y posibilidades de investigación cuando se obtienen datos de representatividad nacional. Los resultados indican que es necesario el trabajo colaborativo, pues permite la integración y el debate entre todos los sujetos involucrados en la investigación. Al delinearse una investigación con esas características, es necesario tener en cuenta las especificidades de las escuelas y de las universidades para que ambas instituciones dialoguen y ocupen el lugar de formadores durante el proceso de obtención y tratamiento de los datos de Investigación

Genetic complexity and the expression of human skin color, eye color, and height: didactic transposition

A ciência Genética está em constante expansão; todavia, a genética ensinada na escola não pode ser considerada somente como uma simplificação do conhecimento produzido pela Ciência. Ela é também resultado de valores e práticas. Assim, o objetivo desta pesquisa foi analisar a transposição didática no que se que refere à expressão da cor da pele, cor dos olhos e estatura humana nos livros didáticos brasileiros e portugueses, bem como no Caderno do Aluno do Estado de São Paulo. Dos livros didáticos de Biologia para os diversos períodos do Ensino Médio brasileiro e Ensino Secundário português, foram analisadas doze coleções recentes: nove coleções brasileiras e três coleções portuguesas. O conteúdo dos livros foi comparado com o conhecimento da literatura de referência para a área da Genética. Neste estudo, foram considerados como literatura de referência alguns artigos científicos atuais e livros acadêmicos utilizados nos cursos de formação de professores. A influência de conhecimentos, valores e práticas sociais nesse processo de transposição didática foi também analisada. Os resultados apontam que a maioria dos livros analisados está próxima da referência ao falar sobre a determinação poligênica das características analisadas. Mais da metade dos materiais analisados menciona a influência do ambiente na determinação da cor da pele e da estatura. Foram também identificados valores e práticas que possivelmente influenciaram no processo de transposição didática desta temática, tais como: 1) a preocupação em evitar uma visão determinista da Genética; 2) a prática de matematizar a Biologia; 3) a prática dos autores em seguir orientações curriculares; 4) a prática e a preocupação com as avaliações de livros didáticos; e 5) a preocupação de evitar preconceitos em uma população composta por diferentes grupos étnicos.Genetic science is continuously expanding, but the genetics taught in school cannot be considered only as a simplification of science produced knowledge: it is also a result of values and practices. This research aimed to analyze the didactic transposition on the expression of skin color, eye color, and human height on Brazilian and Portuguese textbooks and the “São Paulo Student Notebook”. Of the biology textbooks for several periods of secondary education (Brazilian “Ensino Médio” and Portuguese “Ensino Secundário”), twelve recent ones were analyzed in detail: nine Brazilian collections and three Portuguese collections. The content of these textbooks was compared with the contents of the reference literature in the genetics area. In this study, reference literature includes some recent scientific papers and academic books for teacher training. The influence of knowledge, values, and social practices on this process of didactic transposition was also a matter of analysis. Results showed that most textbooks are close to the scientific literature in discussing the polygenic determination of the characteristics analyzed. About half of the analyzed books mentioned the influence of the environment. Values and practices influencing didactic transposition of these topics were also identified, such as 1) concerns about avoiding a deterministic view of genetics; 2) the practice of mathematizing biology; 3) the authors’ practices in following curriculum guidelines; 4) practices and concerns related to textbook evaluation; and 5) concerns with avoiding bias within populations composed of different ethnic groups.Agradecemos o apoio financeiro da Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) ao Processo: 2015/09970-8 e ao Projeto Estratégico Português UID/CED/00317/2019 do CIEC (Centro de Investigação em Estudos da Criança) da Universidade do Minho (FCT R&D unit 317)

Use of lymphocyte cultures for BrdU replication banding patterns in anuran species (Amphibia)

Descreve-se a padronização da cultura de linfócitos com a finalidade de melhorar as preparações citológicas de espécies de anfíbios anuros. Esta metodologia permite o uso do tratamento pelo BrdU para se obter padrões de bandas de replicação nos cromossomos dessas espécies.We describe the standardization of lymphocyte culture procedures in order to improve cytological preparations of anuran species. This methodology permits the use of 5-bromodeoxyuridine (BrdU) treatment to obtain replication banding patterns in the chromosomes of these species.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Cytogenetic analysis of Phyllomedusa distincta Lutz, 1950 (2n = 2x = 26), P. tetraploidea Pombal and Haddad, 1992 (2n = 4x = 52), and their natural triploid hybrids (2n = 3x = 39) (Anura, Hylidae, Phyllomedusinae)

Background: Natural polyploidy has played an important role during the speciation and evolution of vertebrates, including anurans, with more than 55 described cases. The species of the Phyllomedusa burmeisteri group are mostly characterized by having 26 chromosomes, but a karyotype with 52 chromosomes was described in P. tetraploidea. This species was found in sintopy with P. distincta in two localities of São Paulo State (Brazil), where triploid animals also occur, as consequence of natural hybridisation. We analyse the chromosomes of P. distincta, P. tetraploidea, and their triploid hybrids, to enlighten the origin of polyploidy and to obtain some evidence on diploidisation of tetraploid karyotype.Results: Phyllomedusa distincta was 2n = 2x = 26, whereas P. tetraploidea was 2n = 4x = 52, and the hybrid individuals was 2n = 3x = 39. In meiotic phases, bivalents were observed in the diploid males, whereas both bivalents and tetravalents were observed in the tetraploid males. Univalents, bivalents or trivalents; metaphase II cells carrying variable number of chromosomes; and spermatids were detected in the testis preparations of the triploid males, indicating that the triploids were not completely sterile. In natural and experimental conditions, the triploids cross with the parental species, producing abnormal egg clutches and tadpoles with malformations. The embryos and tadpoles exhibited intraindividual karyotype variability and all of the metaphases contained abnormal constitutions. Multiple NORs, detected by Ag-impregnation and FISH with an rDNA probe, were observed on chromosome 1 in the three karyotypic forms; and, additionally, on chromosome 9 in the diploids, mostly on chromosome 8 in the tetraploids, and on both chromosome 8 and 9 in the triploids. Nevertheless, NOR-bearing chromosome 9 was detected in the tetraploids, and chromosome 9 carried active or inactive NORs in the triploids. C-banding, base-specific fluorochrome stainings with CMA3 and DAPI, FISH with a telomeric probe, and BrdU incorporation in DNA showed nearly equivalent patterns in the karyotypes of P. distincta, P. tetraploidea, and the triploid hybrids.Conclusions: All the used cytogenetic techniques have provided strong evidence that the process of diploidisation, an essential step for stabilising the selective advantages produced by polyploidisation, is under way in distinct quartets of the tetraploid karyotype. © 2013 Gruber et al.; licensee BioMed Central Ltd

Multiple nucleolus organizer regions in Leptodactylus mystacinus (Amphibia, Anura) and comments on its systematic position in the L fuscus group based on cytogenetic and molecular analyses

Specimens of Leptodactylus mystacinus from Brazil were karyotyped with conventional and differential staining. The 2n = 22 karyotype is similar to that found for the majority of the Leptodactylus, the karyotypic conservatism also confirmed by the similarity of the replication banding patterns with those previously described. L. mystacinus has a small amount of C-banded heterochromatin, located mainly at the centromeres, although telomeric or interstitial bands have also been noticed. With DA/CMA(3) some chromosome regions showed slightly bright fluorescence, and with DA/DAPI, no particular AT-rich repetitive region was observed. Silver staining showed an extensive inter- and intraindividual variation in the number and position of Ag-positive regions, in 1p, 4p, 8p, 8q, and 11p. Nevertheless, FISH using rDNA probes confirmed only the signals on the short arms of chromosomes 4 and 8 as true NORs. The remaining silver stained regions are probably due to the heterochromatin with some affinity to the Ag-staining. Phylogenetic analysis based on partial cytochrome b sequence revealed that L. mystacinus forms a basal branch, so that the presence of multiple NORs in pairs 4 and 8 in this species indicates an autapomorphy

Comparative analysis based on replication banding reveals the mechanism responsible for the difference in the karyotype constitution of treefrogs Ololygon and Scinax (Arboranae, Hylidae, Scinaxinae)

According to the recent taxonomic and phylogenetic revision of the family Hylidae, species of the former Scinax catharinae (Boulenger, 1888) clade were included in the resurrected genus Ololygon Fitzinger, 1843, while species of the Scinax ruber (Laurenti, 1768) clade were mostly included in the genus Scinax Wagler, 1830, and two were allocated to the newly created genus Julianus Duellman et al., 2016. Although all the species of the former Scinax genus shared a diploid number of 2n = 24 and the same fundamental number of chromosome arms of FN = 48, two karyotypic constitutions were unequivocally recognized, related mainly to the distinct size and morphology of the first two chromosome pairs. Some possible mechanisms for these differences had been suggested, but without any experimental evidence. In this paper, a comparison was carried out based on replication chromosome banding, obtained after DNA incorporation of 5-bromodeoxiuridine in chromosomes of Ololygon and Scinax. The obtained results revealed that the loss of repetitive segments in chromosome pairs 1 and 2 was the mechanism responsible for karyotype difference. The distinct localization of the nucleolus organizer regions in the species of both genera also differentiates the two karyotypic constitutions

Cytogenetic analysis of Cycloramphus boraceiensis Heyer (Anura, Leptodactylidae)

Cytogenetic studies on Cycloramphus boraceiensis Heyer, 1983 collected in Picinguaba, Ubatuba, State of São Paulo are presented. The species has 2n=26 karyotype formed by metacentrics, submetacentrics, and one telocentric pair which carries Ag-NORs. The C-banding patterns is also described