New occurrence of B chromosomes in Partamonahelleri (Friese, 1900) (Hymenoptera, Meliponini)

Cytogenetic analyses of the stingless bee Partamona helleri collected in the state of Bahia, Northeast Brazil revealed the chromosome numbers n = 18 in the haploid males and 2n = 35 in the diploid females. All karyotypes displayed one large acrocentric B chromosome, which differs from the minute B chromosomes previously described in the populations from southeastern Brazil. Giemsa staining, C-banding and DAPI/CMA3 fluorochrome staining also revealed a remarkable interpopulational divergence regarding both the regular karyotype and the B chromosomes. The B chromosomes found in the samples from Jequié, Bahia, were entirely heterochromatic, while those found in Cravolândia, Bahia, displayed a euchromatic portion at the telomeric end of the long arm. CMA 3 labeling sites varied from seven to eight between the two localities in Bahia, due to the presence of an extra GC-rich block in the karyotype of the samples from Jequié. This is the first report of a large B chromosome in P. helleri and reveals the occurrence of a geographic differentiation within this species

Cytogenetic characterization of Partamona cupira (Hymenoptera, Apidae) by fluorochromes

Four colonies of the stingless bee Partamona cupira (Hymenoptera: Apidae) were cytogenetically analyzed using conventional staining and the fluorochromes CMA3 e DAPI. The females have 2n = 34 chromosomes (2K = 32 M¯+2 A¯). Some females, however, presented an additional large B acrocentric chromosome, to a total of 2n = 35. Chromosome B and the chromosomal pairs 2, 9 and 10 showed CMA 3+ bands, indicating an excess of CG base-pairs. A clear association was verified between the P. helleri B chromosome SCAR marker and the presence of a B chromosome in P. cupira. The data obtained suggests that B chromosomes in P. helleri and P. cupira share a common origin

Occurrence of B chromosomes in Tetragonisca Latreille, 1811 (Hymenoptera, Apidae, Meliponini): A new contribution to the cytotaxonomy of the genus

Tetragonisca angustula and Tetragonisca fiebrigi have recently been listed as valid species. This study aimed to cytogenetically investigate both species, emphasizing the new registry of B chromosomes in the tribe Meliponini. We analyzed colonies of T. angustula and T. fiebrigi collected at Tangará da Serra, Mato Grosso, Brazil, through conventional Giemsa staining, C-banding, and base-specific fluorochrome staining (CMA3/DAPI). T. angustula showed 2n = 34 chromosomes in females and n = 17 in males, with karyotype formula 2K = 34AM. T. fiebrigi showed numeric variation, with chromosome number varying from 2n = 34 to 2n = 36 in females and from n = 17 to n = 18 in males, with karyotype formula 2K = 32AM+2AMc and 2K = 32AM+2AMc + 1 or 2 B-chromosomes. The B chromosomes are heterochromatic. In T. fiebrigi, the CMA3/DAPI staining revealed four chromosomes with a CMA3 positive band. All individuals from the same colony showed the same number of B chromosomes. T. angustula and T. fiebrigi showed karyotype divergence, principally due to the presence of B chromosomes, which are found only in T. fiebrigi. Our data corroborate the status of valid species for both T. angustula and T. fiebrigi, as recently proposed

Cytogenetic characterization of Melipona rufiventris Lepeletier 1836 and Melipona mondury Smith 1863 (Hymenoptera, Apidae) by C banding and fluorochromes staining

The stingless bees Melipona rufiventris and M. mondury were analyzed cytogenetically by conventional staining with Giemsa, C-banding and sequential staining with the fluorochromes CMA3/DA/DAPI. Both species presented 2n = 18 and n = 9, except for one colony of M. rufiventris, in which some individuals had 2n = 19 due to the presence of a B chromosome. After Giemsa staining and C-banding the chromosomes appeared very condensed and presented a high heterochromatic content, making it difficult to localize the centromere and therefore to visualize the chromosomes morphology. The constitutive heterochromatin was located in interstitial chromosome regions covering most of the chromosomes extension and consisted mainly of AT, as shown by DAPI staining. The euchromatin was restricted to the chromosome extremities and was GC-rich, as evidenced by CMA3 staining. The B chromosome was CMA3-negative and DAPI-positive, a heterochromatic constitution similar to that of the A genome chromosomes

The effect of autologous costal perichondrium graft with butyl-2-cyanoacrylate in provoked injury in the articular cartilage of rabbit s knee

The purpose of this study was to verify the effect of the perichondrium graft with butyl-2-cyanoacrylate in provoked injury in the articular cartilage of rabbit`s knee. Male adult animals were used, divided in 2 groups, called Group A and Group B, with 17 animals each. The Group A animals were reoperated in 4 weeks and the Group B animals in 8 weeks. A 2 cm fragment was taken out from the 7th costal cartilage from which the perichondrium was removed. Two osteo-cartilaginous cylinders were taken out from each medialis condyles of the femurs in the same animal. The articular cartilage of the cylinder was replaced in one side by the perichondrium with a thin layer of sticking-tissue in its external face and only the articular cartilage was removed from the other side. The cylinders were replaced in the femurs. Macroscopically, in Group A, most of the injuries which received the perichondrium were found completely covered with tissue and all the lesions without perichondrium were only partilly covered. In Group B, no macroscopic significant difference in the covering of the injuries was found. Statistically, There was no microscopical significant difference between the injuries with and without perichondrium of the Group A and Group B and neither groups A and B.A finalidade desse estudo foi verificar o efeito do enxerto autólogo de pericôndrio com butil-2-cianoacrilato em lesão provocada na cartilagem articular do joelho de coelhos. Foram utilizados animais machos, adultos, divididos em 2 grupos, denominados de Grupo A e de Grupo B, de 17 animais cada um. Os animais do Grupo A foram reoperados com 4 semanas e os do Grupo B com 8 semanas. Foi retirado um fragmento de 2 cm da 7ª cartilagem costal esquerda do qual se descolou o pericôndrio. Retiraram-se dois cilindros ósseo-cartilaginosos, um de cada côndilo femural medial do mesmo animal. De um lado a cartilagem articular do cilindro foi substituida por pericôndrio com um fina camada do adesivo tecidual na sua face externa e do outro lado só foi retirada a cartilagem articular. Os cilindros foram recolocados nos fêmures. Macroscopicamente, no Grupo A, encontrou-se a maioria das lesões com pericôndrio recobertas totalmente com tecido e todas as lesões sem pericôndrio recobertas parcialmente. No Grupo B, não se encontrou diferença macroscópica significante entre a cobertura total e parcial com tecido, das lesões. Estatisticamente, não houve diferença microscópica significante entre as lesões com pericôndrio e sem pericôndrio do Grupo A e do Grupo B e nem entre os Grupos A e B.Faculdade de Ciências Médicas de Pouso AlegreUniversidade Federal de São Paulo (UNIFESP)UNIFESPSciEL