A phylogenetic analysis using multidirectional chromosome painting of three species (Uroderma magnirostrum, U. bilobatum and Artibeus obscurus) of subfamily Stenodermatinae (Chiroptera-Phyllostomidae).

The species of genera Uroderma and Artibeus are medium-sized bats belonging to the family Phyllostomidae and subfamily Stenodermatinae (Mammalia, Chiroptera) from South America. They have a wide distribution in the Neotropical region, with two currently recognized species in Uroderma and approximately 20 species in Artibeus. These two genera have different rates of chromosome evolution, with Artibeus probably having retained the ancestral karyotype for the subfamily. We used whole chromosome paint probe sets from Carollia brevicauda and Phyllostomus hastatus on Uroderma magnirostrum, Uroderma bilobatum, and Artibeus obscurus. With the aim of testing the previous phylogenies of these bats using cytogenetics, we compared these results with published painting maps on Phyllostomidae. The genome-wide comparative maps based on chromosome painting and chromosome banding reveal the chromosome forms that characterize each taxonomic level within the Phyllostomidae and show the chromosome evolution of this family. Based on this, we are able to suggest an ancestral karyotype for Phyllostomidae. Our cladistic analysis is an independent confirmation using multidirectional chromosome painting of the previous Phyllostomidae phylogenies.

Genetic and morphological variability in South American rodent Oecomys (Sigmodontinae, Rodentia): evidence for a complex of species.

The rodent genus Oecomys (Sigmodontinae) comprises ~16 species that inhabit tropical and subtropical forests in Central America and South America. In this study specimens of Oecomys paricola Thomas, 1904 from Belém and Marajó island, northern Brazil, were investigated using cytogenetic, molecular and morphological analyses. Three karyotypes were found, two from Belém (2n = 68, fundamental number (FN) = 72 and 2n = 70, FN = 76) and a third from Marajó island (2n = 70, FN = 72). No molecular or morphological differences were found between the individuals with differing cytotypes from Belém, but differences were evident between the individuals from Belém and Marajó island. Specimens from Belém city region may represent two cryptic species because two different karyotypes are present in the absence of significant differences in morphology and molecular characteristics. The Marajó island and Belém populations may represent distinct species that have been separated for some time, and are in the process of morphological and molecular differentiation as a consequence of reproductive isolation at the geographic and chromosomal levels. Thus, the results suggest that O. paricola may be a complex of species.

Genomic mapping of human chromosome paints on the threatened masked Titi monkey (Callicebus personatus).

Callicebus is a complex genus of neotropical primates thought to include 29 or more species. Currently, the genus is divided into 5 species groups: donacophilus, cupreus, moloch, torquatus and personatus. However, the phylogenetic relationships among the species are still poorly understood. This genus is karyotypically diverse and shows extensive variation in diploid number (2n = 16 to 50). To foster a better understanding of the chromosomal diversities and phylogenetic relationships among the species of Callicebus, we performed a chromosome-painting analysis on the Callicebus personatus genome using human probes, and compared the resulting hybridization map to those of previously mapped titi species. We detected 38 hybridization signals per haploid autosomal set of C. personatus. Few ancestral syntenies were conserved without rearrangement, but 4 human associations (HSA20/13, 3c/8b, 1b/1c and 21/3a/15a/14) were demonstrated to be apomorphic traits for C. persona tus. G-banding suggested that these associations are shared with C. nigrifrons and C. coimbrai (personatus group), while C. personatus is linked with C. pallescens (donacophilus group) by 2 synapomorphies: HSA10b/11 (submetacentric) and an inversion of HSA1a.

Reciprocal chromosome painting between two South American bats: Carollia brevicauda and Phyllostomus hastatus (Phyllostomidae, Chiroptera).

The Neotropical Phyllostomidae family is the third largest in the order Chiroptera, with 56 genera and 140 species. Most researchers accept this family as monophyletic but its species are anatomically diverse and complex, leading to disagreement on its systematics and evolutionary relationships. Most of the genera of Phyllostomidae have highly conserved karyotypes but with intense intergeneric variability, which makes any comparative analysis using classical banding difficult. The use of chromosome painting is a modern way of genomic comparison on the cytological level, and will clarify the intense intergenus chromosomal variability in Phyllostomidae. Whole chromosome probes of species were produced as a tool for evolutionary studies in this family from two species from different subfamilies, Phyllostomus hastatus and Carollia brevicauda, which have large morphological and chromosomal differences, and these probes were used in reciprocal chromosome painting. The hybridization of the Phyllostomus probes on the Carollia genome revealed 24 conserved segments, while the Carollia probes on the Phyllostomus genome detected 26 segments. Many chromosome rearrangements have occurred during the divergence of these two genera. The sequence of events suggested a large number of rearrangements during the differentiation of the genera followed by high chromosomal stability within each genus.

Conventional cytogenetic characterization of a new cell line, ACP01, established from a primary human gastric tumor

Gastric cancer is the second most frequent type of neoplasia and also the second most important cause of death in the world. Virtually all the established cell lines of gastric neoplasia were developed in Asian countries, and western countries have contributed very little to this area. In the present study we describe the establishment of the cell line ACP01 and characterize it cytogenetically by means of in vitro immortalization. Cells were transformed from an intestinal-type gastric adenocarcinoma (T4N2M0) originating from a 48-year-old male patient. This is the first gastric adenocarcinoma cell line established in Brazil. The most powerful application of the cell line ACP01 is in the assessment of cytotoxicity. Solid tumor cell lines from different origins have been treated with several conventional and investigational anticancer drugs. The ACP01 cell line is triploid, grows as a single, non-organized layer, similar to fibroblasts, with focus formation, heterogeneous division, and a cell cycle of approximately 40 h. Chromosome 8 trisomy, present in 60 percent of the cells, was the most frequent cytogenetic alteration. These data lead us to propose a multifactorial triggering of gastric cancer which evolves over multiple stages involving progressive genetic changes and clonal expansion.

Conventional cytogenetic characterization of a new cell line, ACP01, established from a primary human gastric tumor.

Gastric cancer is the second most frequent type of neoplasia and also the second most important cause of death in the world. Virtually all the established cell lines of gastric neoplasia were developed in Asian countries, and western countries have contributed very little to this area. In the present study we describe the establishment of the cell line ACP01 and characterize it cytogenetically by means of in vitro immortalization. Cells were transformed from an intestinal-type gastric adenocarcinoma (T4N2M0) originating from a 48-year-old male patient. This is the first gastric adenocarcinoma cell line established in Brazil. The most powerful application of the cell line ACP01 is in the assessment of cytotoxicity. Solid tumor cell lines from different origins have been treated with several conventional and investigational anticancer drugs. The ACP01 cell line is triploid, grows as a single, non-organized layer, similar to fibroblasts, with focus formation, heterogeneous division, and a cell cycle of approximately 40 h. Chromosome 8 trisomy, present in 60% of the cells, was the most frequent cytogenetic alteration. These data lead us to propose a multifactorial triggering of gastric cancer which evolves over multiple stages involving progressive genetic changes and clonal expansion.

Chromosomal studies in Callicebus donacophilus pallescens, with classic and molecular cytogenetic approaches: multicolour FISH using human and Saguinus oedipus painting probes.

This paper presents the karyotype of Callicebus donacophilus pallescens for the first time. The analysis included G-, C-, NOR-banding techniques and FISH with chromosome painting probes from Saguinus oedipus and Homo sapiens. The results were compared with the karyotypes of Callicebus moloch donacophilus and C. moloch previously published. These three karyotypes display the same diploid number (2n = 50) but diverge about the number of biarmed and acrocentric chromosomes. The acrocentrics 14 and 15 from C. m. donacophilus and C. moloch have undergone an in-tandem fusion originating a large acrocentric (pair 10) in C. d. pallescens. The major submetacentric pair (pair 1) from C. d. donacophilus and C. moloch have undergone fission originating two acrocentric pairs in C. d. pallescens (pairs 15 and 22). Herein was evidence that, in spite of the high interspecific variation among Callicebus, most of the chromosomes remained conserved.