Cytogenetics

New cytogenetic aberrations found in a case of aggressive retinoblastoma

J. E. X. S. Barros, Soares-Ventura, E. M., Santos, N., Amaral, B. A. S., Oliveira, F. M., Cruz, R. S. Vera, Morais, V. L. L., Marques-Salles, T. J., and Muniz, M. T. C., “New cytogenetic aberrations found in a case of aggressive retinoblastoma”, vol. 11. pp. 1666-1670, 2012.

We describe a case of retinoblastoma with an atypical presentation and previously unreported cytogenetic aberrations. A 19-month-old girl with left intraocular retinoblastoma was treated with enucleation and chemotherapy. The disease showed aggressive evolution within a short period between diagnosis and relapse. Eight months after diagnosis, a new large tumor was present in the orbit of the right eye, with diffuse bone pain, pancytopenia and diffuse infiltration into the bone marrow and the central nervous system. The child did not respond to treatment and died.

Karyotype and spermatogenesis in Triatoma lenti (Hemiptera: Triatominae), a potential Chagas vector

K. C. C. Alevi, Mendonça, P. P., Succi, M., Pereira, N. P., Rosa, J. A., and Azeredo-Oliveira, M. T. V., “Karyotype and spermatogenesis in Triatoma lenti (Hemiptera: Triatominae), a potential Chagas vector”, vol. 11, pp. 4278-4284, 2012.

All species of Triatominae are susceptible to infection by Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae) and consequently, potential insect vectors of Chagas disease. Currently, there are 140 known species of triatomine bugs, which can be grouped into specific species complexes. The species Triatoma lenti (Hemiptera: Triatominae) is found only in Brazil and is considered a potential vector of Chagas disease. We karyotyped male T. lenti and examined its spermatogenesis in detail.

Cobalt chloride induces metaphase when topically applied to larvae and pupae of the stingless bee Melipona scutellaris (Hymenoptera, Apidae, Meliponini)

C. Ueira-Vieira, Tavares, R. R., Morelli, S., Pereira, B. B., Silva, R. P., Torres-Mariano, A. R., Kerr, W. E., and Bonetti, A. M., “Cobalt chloride induces metaphase when topically applied to larvae and pupae of the stingless bee Melipona scutellaris (Hymenoptera, Apidae, Meliponini)”, vol. 12, pp. 2032-2037, 2013.

In order to optimize preparations of bee metaphases, we tested cobalt chloride, which has been used as a metaphase inducer in other organisms, such as hamsters and fish. Four microliters of 65 mM cobalt chloride aqueous solution was topically applied to larval and pupal stages of the stingless bee Melipona scutellaris. The cerebral ganglion was removed after treatment and prepared for cytogenetic analysis. Identically manipulated untreated individuals were used as controls. The number of metaphases was increased 3-fold in treated individuals compared to controls.

Spermatogenesis in Triatoma melanocephala (Hemiptera: Triatominae)

K. C. C. Alevi, Mendonça, P. P., Pereira, N. P., Rosa, J. A., and Azeredo-Oliveira, M. T. V., “Spermatogenesis in Triatoma melanocephala (Hemiptera: Triatominae)”, vol. 12. pp. 4944-4947, 2013.

Triatoma melanocephala is a rare species of Hemiptera. It belonged to the Brasiliensis subcomplex and presents morphological characteristics very close to those of Triatoma vitticeps. We investigated spermatogenesis of T. melanocephala and compared it with that of T. vitticeps in order to determine whether these organisms have similar cytogenetic characteristics. Lacto-acetic orcein staining was used to observe all stages of meiosis.

Tetraploidization in Wilms tumor in an infant

E. T. Valera, Brassesco, M. S., Scrideli, C. A., and Tone, L. G., “Tetraploidization in Wilms tumor in an infant”, vol. 9. pp. 1577-1581, 2010.

Genetic instability is frequent in human cancer. Unscheduled tetraploidization can trigger cell transformation and tumorigenesis. We made a cytogenetic analysis by Giemsa-trypsin banding of a stage I, biphasic Wilms tumor diagnosed in a 10-month-old male. An evident karyotypic heterogeneity was found. Four different subclones of tumor cells were observed, with DNA content varying from diploid to near-tetraploid complements. The genetic events involved in the acquisition of aneuploidy in Wilms tumor remain unclear.

Chromosome number and cytogenetics of Euphorbia heterophylla L.

J. R. Aarestrup, Karam, D., and Fernandes, G. W., “Chromosome number and cytogenetics of Euphorbia heterophylla L.”, vol. 7, pp. 217-222, 2008.

Euphorbia heterophylla L. (Euphorbiaceae) is a herbaceous species of great economic importance due to its invasive potential and consequent damage to agriculture and pasture land. For the first time, we provide information on its chromosome number, morphology, and behavior of mitotic chromosomes. Seeds were germinated and submitted to four treatments to obtain metaphases: 0.5% colchicine for 2 to 5 h, at ambient temperature; 0.5% colchicine for 16 to 24 h; 0.0029 M 8-hydroxyquinoline (8-HQ) for 2 to 5 h at ambient temperature, and 0.0029 M 8-HQ for 16 to 24 h at 4ºC.

Karyotype description of two species of Hypostomus (Siluriformes, Loricariidae) of the Planalto da Bodoquena, Brazil

S. S. Cereali, Pomini, E., Rosa, R., Zawadzki, C. H., Froehlich, O., and Giuliano-Caetano, L., “Karyotype description of two species of Hypostomus (Siluriformes, Loricariidae) of the Planalto da Bodoquena, Brazil”, vol. 7, pp. 583-591, 2008.

Hypostomus sp 3-Córrego Salobrinha NUP 4247 and Hypostomus sp 2-Rio Perdido NUP 4249, collected in the Planalto da Bodoquena, Paraguay River basin, Brazil, were characterized cytogenetically. Hypostomus sp 3-Córrego Salobrinha showed two modal numbers. This polymorphism consists of the presence of two extrachromosomes. It was not possible to define the diploid number in four specimens, where cell lineages had 2n = 83 and 2n = 84 chromosomes in one individual, and 2n = 82, 2n = 83 and 2n = 84 chromosomes in the others.

Cytogenetic analysis in the spermatogenesis of Triatoma melanosoma (Reduviidae; Heteroptera)

V. B. Bardella, Azeredo-Oliveira, M. T. V., and Tartarotti, E., “Cytogenetic analysis in the spermatogenesis of Triatoma melanosoma (Reduviidae; Heteroptera)”, vol. 7, pp. 326-335, 2008.

Triatomines are of great concern in public health because they are vectors of Chagas’ disease. This study presents an analysis of the species Triatoma melanosoma. The cytogenetic characteristics of triatomines include holocentric chromosomes, post-reductional meiosis in the sex chromosomes and nucleolar fragmentation in the meiotic cycle. The methodology utilized consisted of the techniques of lacto-acetic orcein staining and silver ion impregnation. The organs analyzed were adult testicles.

Unusual chromosome numbers in Paspalum L. (Poaceae: Paniceae) from Brazil

A. P. S. Peñaloza, Côrtes, A. L., Pozzobon, M. T., Santos, S., Rua, G. H., and Valls, J. F. M., “Unusual chromosome numbers in Paspalum L. (Poaceae: Paniceae) from Brazil”, vol. 7, pp. 399-406, 2008.

Somatic chromosome numbers were determined for 20 new germplasm accessions of Paspalum, belonging to 17 species collected in Brazil. Chromosome number is reported for the first time for P. reduncum (2n = 18), P. cinerascens (2n = 20), P. cordatum (2n = 20), P. filgueirasii (2n = 24), P. ammodes (2n = 36), P. bicilium (2n = 40), P. heterotrichon (2n = 40), and P. burmanii (2n = 48). New cytotypes were confirmed for two germplasm accessions of P. carinatum (2n = 30) and P.

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