Karyotypic conservatism in samples of Characidium cf. zebra (Teleostei, Characiformes, Crenuchidae): physical mapping of ribosomal genes and natural triploidy

Basic and molecular cytogenetic analyses were performed in specimens of Characidium cf. zebra from five collection sites located throughout the Tietê, Paranapanema and Paraguay river basins. The diploid number in specimens from all samples was 2n = 50 with a karyotype composed of 32 metacentric and 18 submetacentric chromosomes in both males and females. Constitutive heterochromatin was present at the centromeric regions of all chromosomes and pair 23, had additional interstitial heterochromatic blocks on its long arms. The nucleolar organizer regions (NORs) were located on the long arms of pair 23, while the 5S rDNA sites were detected in different chromosomes among the studied samples. One specimen from the Alambari river was a natural triploid and had two extra chromosomes, resulting in 2n = 77. The remarkable karyotypic similarity among the specimens of C. cf. zebra suggests a close evolutionary relationship. on the other hand, the distinct patterns of 5S rDNA distribution may be the result of gene flow constraints during their evolutionary history.

Natural triploidy and B chromosomes in Astyanax scabripinnis (Characiformes, Characidae): a new occurrence

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The Karyotype of Holoaden luederwaldti (Anura, Strabomantidae), with Report of Natural Triploidy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

NATURAL TRIPLOIDY IN ASTYANAX-SCABRIPINNIS (PISCES, CHARACIDAE) AND SIMULTANEOUS OCCURRENCE OF MACRO B-CHROMOSOMES

The occurrence of natural triploidy in two specimens of Astyanax scabripinnis collected in the Araqua river and in the Corrego das Pedras stream, respectively, is noticed. The triploid specimen from the Araqua river presented one macro B-chromosome and the triploid specimen from Corrego das Pedras stream presented two macro B-chromosomes. The C-banding performed in the specimen from the Araqua river confirmed the triploidy and showed that the macro B-chromosome was entirely heterochromatic. Ag-NOR characterization showed two chromosomes involved in the nucleolar activity in both specimens. Some aspects related to the origin of triploid fishes are described.

Spontaneous triploidy and NOR activity in Eigenmannia sp. (Pisces, Sternopygidae) from the Amazon basin

The occurrence of a natural triploid among diploid individuals of Eigenmannia sp from the Amazon basin is described. The diploid individuals had 2n=31 and 32 chromosomes, the difference in chromosome number being due to a Robertsonian rearrangement. The triploid individual presented 2n=46 and had two fused acrocentrics. NOR activity was present in the three homologues of triploid and a NOR polymorphism was detected in the triploid and diploids. © 1985 Dr W. Junk Publishers.

Synaptonemal complex formation in spermatocytes of the autotriploid rainbow trout, Oncorhynchus mykiss (Pisces, Salmonidae)

Meiotic cells of triploid male rainbow trouts were analyzed by a surface-spreading SC technique in order to show the process of chromosome synapsis. At zygotene the formation of SCs involved, almost exclusively, two sets of lateral elements (LEs), and the remaining set of LEs presented different synaptic configurations involving one, two, three, or four LEs. The absence of SCs involving more than two LEs from mid- to late pachytene indicates that the multivalents produced by synapsis involving more than two LEs, are eliminated before the end of pachytene; thus, the mechanism of chromosome pairing in triploid male rainbow trouts produces, almost exclusively, bivalents with a probable extensive nonhomologous synapsis involving the extra set of chromosomes.

Doses de N e K aplicadas via fertirrigação e espaçamento entre plantas influenciando o desenvolvimento, a produtividade e as relações hídricas em melancieira com e sem sementes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização citogenética das espécies matrinxã (Brycon amazonicus), piraputanga (Brycon hilarii) e sua geração filial, utilizados na piscicultura brasileira

Pós-graduação em Ciências Biológicas (Zoologia) - IBB

Mecanismos de evolução cromossômica e diferenciação cariotípica em espécies das subfamílias Hylinae (tribos Cophomantini e Lophiohylini) e Phyllomedusinae (Hylidae, Anura, Amphibia)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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 denocarcinoma 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.

Genetic Identification of F1 and Post-F1 Serrasalmid Juvenile Hybrids in Brazilian Aquaculture

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Genetic differentiation among distinct karyomorphs of the wolf fish Hoplias malabaricus species complex (Characiformes, Erythrinidae) and report of unusual hybridization with natural triploidy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Diferenciação gonadal em Piaractus mesopotamicus

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Indução à triploidia no tambaqui Colossoma macropomum, pacu Piaractus mesopotamicus e o respectivo híbrido tambacu

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desempenho zootécnico e caracterização da linhagem germinativa de peixes diploides e triploides de lambari (Astyanax altiparanae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)