Revisao dos dados citogeneticos em especies da família Hylidae (amphibia, anura): resultados e perspectivas

Abstract

Recebido para publicação em 12/12/2008Aceito para publicação em 07/03/2009 RESUMO Células-tronco são caracterizadas por seu estado indiferenciado e seu alto poder de autorrenovação através de divisões assimétricas. Sob a infl uência de determinados sinais biológicos, elas podem se diferenciar em células fenotipicamente distintas de seus precursores. São divididas em dois grandes grupos de acordo com o local de seu isolamento: embrionárias, que são as células retiradas da camada celular interna do blastocisto; e adultas, que são aquelas encontradas em diversos locais de tecidos pós-natais. As células-tronco mesenquimais, por sua vez, formam um grupo heterogêneo de células adultas multipotentes, capazes de originar tecidos mesenquimais: ósseo, adiposo e cartilaginoso, sendo encontradas tanto em tecidos fetais quanto em adultos. O líquido amniótico humano, um fl uido complexo e dinâmico que envolve o feto durante a gestação, contém uma variedade de célu-las esfoliadas do embrião em sua composição. Procedimentos bem estabelecidos de isolamento, crescimento e expansão das células do líquido amniótico podem proporcionar uma fonte alternativa de células-tronco mesenquimais com diversas aplicações biomédicas.Palavras-Chaves: Células-tronco mesenquimais. Líquido amniótico. Terapia celular. ABSTRACTStem cells are characterized by their undifferentiated state and their high capacity of self renewal through asymmetric divisions. Under the infl uence of certain biological signals they can differentiate into specialized cells phenotypically different from their precursors. They are divided into to their place of origin: embryonic

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)

“…All of the species exhibited a diploid number of 2n = 24 bi-armed chromosomes, corresponding to the fundamental number of FN = 48 chromosome arms (revisions in Kasahara 2009 andin Peixoto et al 2015). The work of Cardozo et al (2011) stands out for its inclusion of chromosomal data obtained from a large sample of 28 representatives, and because the results were analyzed for the first time from an evolutionary point of view provided by available phylogenies.…”

Chromosome Evolution in Dendropsophini (Amphibia, Anura, Hylinae)

“…Knowledge on chromosome number and morphology in hylids is still sparse, and in Dendropsophini, only 74 of the 234 assigned species have known karyotypes [Catroli and Kasahara, 2009;Cardozo et al, 2011], with most information limited to chromosome numbers. These are available for 1 of the 14 species of Sphaenorhynchus , 3 of the 4 species of Lysapsus , all species of Pseudis , 24 of the 94 species of Dendropsophus , and 39 of the 111 species of Scinax [Catroli and Kasahara, 2009;Cardozo et al, 2011] .…”

“…These are available for 1 of the 14 species of Sphaenorhynchus , 3 of the 4 species of Lysapsus , all species of Pseudis , 24 of the 94 species of Dendropsophus , and 39 of the 111 species of Scinax [Catroli and Kasahara, 2009;Cardozo et al, 2011] . No cytogenetic information is available for Scarthyla and Xenohyla .…”

Comparative cytogenetics of tree frogs of the Dendropsophus marmoratus (Laurenti, 1768) group: conserved karyotypes and interstitial telomeric sequences

“…Although all of the Dendropsophus species karyotyped to date show 2n = 30 (see review in Catroli and Kasahara 2009, Medeiros et al 2013, Suárez et al 2013, Oliveira et al 2016), a noticeable variation in the number of biarmed/telocentric chromosomes is observed among them, suggesting that several chromosomal rearrangements took place after the evolutionary origin of the hypothetical ancestral 30-chromosome karyotype. Karyotypes with only biarmed chromosomes [as in D. minutus (Peters, 1872) (Gruber et al 2005) and D. leali (Bokermann, 1964) (Bogart 1973)] and karyotypes with up to five pairs of telocentric/subtelocentric chromosomes [as in D. labialis (Peters, 1863) (Bogart 1973), D. sanborni (Schmidt, 1944) and D. jimi (Napoli & Caramaschi, 1999) (Medeiros et al 2013)] may be observed.…”

“…Of the nine species groups recognized in Dendropsophus (for a review of the Dendropsophus groups, see Faivovich et al 2005), the D. microcephalus (Cope, 1886) group is the most species-rich (currently with 40 species-Frost 2016) and the most studied cytogenetically (17 species karyotyped-review by Catroli and Kasahara 2009, Medeiros et al 2013, Oliveira et al 2016. It is noteworthy that karyotypes without any telocentric chromosome (in D. leali-Bogart 1973) (Bogart 1973, Kaiser et al 1996, Gruber et al 2005, which currently has 11 species (see Frost 2016) and is the second most cytogenetically studied species group of Dendropsophus (four of the named species are karyotyped).…”