Diss. (sammanfattning) Stockholm : Karol. inst., 2005. / Härtill 6 uppsatser.

O objetivo do presente estudo foi avaliar os efeitos genotóxicos/citotóxicos ocasionados por disjuntores de Haas em células epiteliais esfoliadas da mucosa bucal de pacientes submetidos a tratamento ortodôntico, por meio do ensaio de micronúcleos. Participaram do estudo 22 pacientes entre 06 a 12 anos de idade, de ambos os gêneros, que necessitaram de disjuntores de Haas para correção de mordida cruzada posterior. Foi efetuada a coleta de células epiteliais da mucosa da bochecha, por meio de raspagem suave com escova científica. As células foram coletadas antes (T0), um mês após a instalação do aparelho (T1) e 3 meses após o travamento dos disjuntores (T2). As células foram processadas para obtenção de lâminas, as quais foram coradas com o método de Feulgen/Fast Green para quantificação do número de células normais, cariolíticas, picnóticas, brotos nucleares, bi/trinucleadas e com a presença de micronúcleos, em microscospia de luz. Os resultados foram submetidos à analise estatistica por meio do teste ANOVA, seguido do pós-teste de Tukey. O nível de significância adotado foi de 5%. Os resultados demonstraram que não houve diferença estatisticamente significante com relação à preença de micronúcleos, nos períodos avaliados (p>0,05). Os brotos nucleares sofreram aumento em T1 (p>0,05), com retorno aos níveis baseline em T2. Em relação às outras anormalidades (células cariolíticas, picnóticas e bi/trinucleadas), houve aumento significante em T1 e T2 (p<0,0001). Concluindo, este estudo demonstrou que os disjuntores de Haas não ocasionaram aumento de micronúcleos em células da mucosa bucal. Entretanto, foram observadas aumento estatisticamente significante das células cariolíticas, picnóticas e bi/trinucleadas durante o tratamento, sugerindo possíveis efeitos citotóxicos. / The aim of the present study was to evaluate the genotoxic and cytotoxic effects caused by Haas appliance through micronuclei assay in buccal mucosa epithelial cells of patients submitted to orthodontic treatment. The study included 22 patients between 06 and 12 years of age, both genders, who required Haas appliance for correction of posterior crossbite. Epithelial cells from the cheek mucosa were collected performed by gentle scraping scientific toothbrush. The cells were collected before (T0), one month after the device was installed (T1) and 3 months after the appliance immobilization (T2). The cells were processed to obtain slides and Feulgen/Fast Green was used as staining method for counting the number of normal, karyolytic, pyknotic, nuclear buds, binucleated and micronucleus cells under light microscopy. The cellular abnormalities were evaluated with the parametric tests for comparison of the means by ANOVA test followed by the Tukey post-test. The significance level was 5%. The results of this study showed that there were no statistically significant results for the micronuclei in the evaluated periods (p>0,05). Nuclear buds increased in T1 (p<0,05), returning to baseline levels in T2. In relation to the other abnormalities (cariolytic, pyknotic and bi/trinucleated cells), there were a significant increase in T1 and T2 (p<0.0001). In conclusion, this study demonstrated that Haas appliance did not cause micronuclei increase in cells of buccal mucosa. However, a statistically significant increase in cariolytic, pyknotic and bi/trinucleated cells were observed during treatment, suggesting possible cytotoxic effects.

Common fragile sites are a set of genomic locations with a propensity to form lesions, breaks and gaps on mitotic chromosomes upon induction of replication stress. While the exact reasons for their fragility are unknown, CFS display instability in a cell-type specific manner, suggesting a substantial contribution from an epigenetic component. CFSs also overlap with sites of increased breakage and deletions in tumour cells, as well as evolutionary breakpoints, implying that their features shape genome stability in vivo. Previously, factors such as delays in replication timing, low origin density and transcription of long genes have been implicated in instability at CFS locations but comprehensive molecular studies are lacking. Chromatin structure, an important factor that fits the profile of cell-type specific contributor, has also not been investigated yet. Throughout their efforts to determine the factors that lead to the appearance of CFS lesions, investigators have focused on a single component at a time, potentially missing out complex interactions between cellular processes that could underlie fragility. Additional difficulties come from the cell-type specificity of CFS breakage: it indicates that only cell type-matched data would be informative, limiting the scope for studies using publicly available data. To perform a comprehensive study defining the role of different factors in determining CFS fragility, I explored replication timing, transcriptional landscapes and chromatin environment across a number of CFSs in two cell types exhibiting differential CFS breakage. Initially, I characterised the patterns of CFS fragility in the two cell types on both the cytogenetic and the molecular level. I then used a FISH-based technique to investigate the process of mitotic compaction at active CFS sites and found that the cytogenetically fragile core of these sites sits within larger regions which display a tendency to mis-fold in mitosis. The aberrant compaction of these regions could be observed on cytogenetically normal metaphase chromosomes, suggesting that finer scale abnormalities in chromosome structure underlie the cytogenetically visible breaks at fragile sites. I also investigated the links between transcription of long genes and CFS fragility using two approaches: I quantified levels of expression across all fragile sites using RNA-seq and modified transcription at a single active CFS using the CRISPR genome engineering methodology. My results indicate a complex interplay between transcription and CFS fragility: no simple linear correlation can be observed, but an increase of transcriptional levels at the active CFS led to a corresponding increase in fragility. To investigate the influence of the cell type specific replication programme and replication stress on CFS instability, I mapped replication timing genome-wide in unperturbed cells and under conditions of replication stress in both cell types. I found that replication stress induces bi-directional changes in replication timing throughout the genome as well as at CFS regions. Surprisingly, the genomic regions showing the most extreme replication timing alterations under replication stress do not overlap with CFS, implying that CFS instability is not fully explained by replication delays as previously suggested. Instead, I observed a range of replication-stress induced timing changes across CFS regions: while some CFSs appear under-replicated, others display switches to both earlier and later replication as well as differential recruitment of both early and late origins, implying that dis-regulation of replication timing and origin firing, rather than simply delays, underlie the sensitivity to CFS regions to replication stress. Finally, I investigated large-scale chromatin states at two active CFSs throughout S phase and into G2, the cell cycle stages most relevant stage for CFS breakage. I found that changes in large-scale chromatin architecture accompany the replication timing shifts triggered by replication stress, raising the possibility that such alterations contribute to instability. In conclusion, I assessed the influence of multiple relevant factors on CFS fragility. I found that bi-directional replication timing changes and alterations in interphase chromatin structure are likely to play a role, converging to promote mitotic folding problems which ultimately result in the well-described cytogenetic lesions on metaphase chromosomes and genomic instability.

Entre as diversas espécies de plantas forrageiras, destaca-se Paspalum notatum Flugge, uma das mais importantes nas pastagens nativas do sul do Brasil. Os ecótipos nativos são autotetraplóides, reproduzindo-se através apomixia. Porém, a variedade Paspalum notatum (cultivar Pensacola) é diplóide de reprodução sexual e pode ser usada em cruzamentos com plantas apomíticas após duplicação cromossômica. O objetivo deste trabalho foi avaliar genótipos poliploidizados quanto ao modo de reprodução, comportamento meiótico e estimar a fertilidade masculina e feminina. Três plantas diploides de reprodução sexual da cv. Pensacola tiveram seu número cromossômico duplicado artificialmente. A planta WKS 3 apresentou modificação em seu modo de reprodução após a duplicação, que passou a ser apomítico. Já as plantas WKS 63 e WKS 92 confirmaram o modo de reprodução sexual idêntico ao genótipo de origem. As plantas analisadas WKS 3, WKS 63 e WKS 92 apresentaram anormalidades meióticas relacionadas à poliploidia, entretanto essas anormalidades não comprometeram os produtos meióticos, que foram predominantemente tétrades regulares e satisfatória fertilidade polínica, variando de 88,7 a 95,7%. O pareamento cromossômico na fase da diacinese foi variável entre as plantas: WKS 3 apresentou associações predominantemente bivalentes com esporádicas associações quadrivalentes, WKS 92 mostrou associações bivalentes, trivalentes e tetravalentes e associações quadrivalentes, enquanto que na planta WKS 63, houve predomínio de associações quadrivalentes. As plantas WKS 63 e WKS 92 apresentaram baixa fertilidade feminina, indicando que a duplicação cromossômica pode afetar esta característica. Estas plantas duplicadas, juntamente com outros genótipos da espécie, previamente selecionados e os ecótipos apomíticos elite do Rio Grande do Sul, foram utilizadas em esquemas de cruzamentos intraespecíficos. A obtenção de híbridos segregantes abriu um grande leque de possibilidades para o melhoramento de plantas forrageiras, melhorando a composição do campo nativo, podendo corroborar com a conservação dos campos sulinos, evitando sua degradação, bem como sendo uma nova opção para a pecuária do sul do país, através da utilização de materiais bem adaptados, diversificando a produção forrageira. Além disso, podendo gerar materiais que possam ser utilizados na recuperação de áreas degradadas. Novos genótipos apomíticos, gerados através de hibridações e que tenham potencial agronômico poderão ser registrados e protegidos no Serviço Nacional de Proteção de Variedades do Ministério da Agricultura, Pecuária e Abastecimento (MAPA). / Among the various species of forage plants, Paspalum notatum Flugge is one of the most important native grassland species of southern Brazil. The native ecotypes are tetraploid and have apomictic reproduction. However, the variety Paspalum notatum (cultivar Pensacola) is diploid and sexual and they can be used in crosses with apomictic plants after chromosome duplication. The objective of this study was to evaluate polyploidized genotypes as the mode of reproduction, meiotic behavior, pollen viability and to evaluate male and female fertility. Three diploid and sexual plants of cultivar Pensacola had chromosome number artificially duplicate. The WKS 3 plant showed change in mode of reproduction after duplication, which became apomictic. And the plants WKS 63 and WKS 92 confirmed sexual reproduction mode like the original genotype. The analyzed plants WKS 3, WKS 63 and WKS 92 presented abnormalities related to polyploidy, however, the abnormalities observed did not compromise the meiotic products which were characterized by regular tetrads and satisfactory pollen fertility varying from 88.7 to 95.7%.Chromosome paired at diakinesis were variable among plants: WKS 3 presented predominantly quadrivalents associations, WKS 92 presented bivalents, trivalents and tetravalents associations and the plant WKS 63, predominantly presented quadrivalents associations. The plants WKS 63 and WKS 92 had low female fertility, showing that chromosome duplication can affect this trait. These duplicate plants along with other genotypes of species previously selected and the elite apomictic ecotypes of Rio Grande do Sul were used in intraspecific crosses. Obtaining hybrids segregating opened a wide range of possibilities for the improvement of forage plants, improving natural pasture composition, can be corroborate with the conservation of the southern fields, preventing its degradation, as well as being a lever for livestock in the South of the country, with the use of materials well suited, diversifying the forage production. Also, can generate materials that can be used in the recovery of degraded areas. New apomictic genotypes produced, generated across the hybridization, with agronomic potential, will can be registered and licensed by the Ministry of Agriculture, Livestock and Supply of Brazil (MAPA).

Made available in DSpace on 2014-06-11T19:26:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-26Bitstream added on 2014-06-13T19:12:50Z : No. of bitstreams: 1 bardella_vb_me_sjrp.pdf: 973541 bytes, checksum: 2642d082f6fe5ee2cb77ab3b60832684 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Os heterópteros apresentam a meiose cística nos túbulos seminíferos. Esses possuem o cisto espermatogonial envolto pelas células císticas, as quais desenvolvem a função de nutrição das células em divisão celular. Quanto às características citogenéticas, esses insetos apresentam cromossomos holocinéticos, baixa variabilidade cariotípica e meiose invertida dos cromossomos sexuais. No presente trabalho foram caracterizadas as células císticas quanto a sua localização, ultraestrutura e citogenética e, também, foram analisados os aspectos citogenéticos de quatro espécies do gênero Triatoma. Foram utilizadas as técnicas de microscopia eletrônica de transmissão, citogenética convencional (orceína e AgNOR), bandamento C CMA3/DAPI e a técnica de hibridização in situ fluorescente (FISH), com sonda de DNAr 45S de Drosophila melanogaster. Os resultados indicaram que a célula cística envolve um cisto espermatogonial e apresenta um grande núcleo com invaginações citoplasmáticas. Em todas as espécies foram observados vários graus de ploidia da célula cística. Triatoma infestans e T. infestans melanosoma apresentaram vários blocos heterocromáticos com a periferia CMA3 + e o interior DAPI+. Associada às bordas dos blocos heterocromáticos foram observados os segmentos de DNAr 45S, além da presença de vários nucléolos em cada núcleo. Triatoma matogrossensis, T. rubrovaria e T. brasiliensis apresentaram apenas um bloco heterocromático com as mesmas características, com exceção de T. brasiliensis, que apresentou em algumas células vários blocos CMA3 + dispersos. Nessas espécies foi observado apenas um nucléolo com similaridade na localização dos sítios de DNAr. Quanto aos aspectos citogenéticos, todas as espécies apresentaram 2n = 20A + XY, com decréscimo do tamanho relativo dos cromossomos. Em T. infestans melanosoma os cromossomos foram... / Heteroptera, or true bugs, exhibit meiosis in their seminiferous tubules. They posses the spermatogonial cysts that are enclosed by cyst cells, which develop the nutritional function of the cells during cell division. In terms of cytogenetic characteristics, these insects possess holokinetic chromosomes, low karyotype variability, and inverted meiosis in the sex chromosomes. In this study, cyst cells from four species of the genus Triatoma were characterized by their location, superstructure, and cytogenetic makeup. Electronic transmission microscopy techniques were used, as well as conventional cytogenetic techniques (Orcein and AgNOR), C-banding with CMA3 and DAPI banding, and Fluorescence in situ Hybridization (FISH) with a 45S DNA probe of Drosophila melanogaster. The results indicated that the the spermatogonial cyst is enclosed by the cyst cell, and that the cyst cell possesses a large nucleus with cytopasmic invaginations. In all species studied, varying degrees of ploidy were observed in the cyst cells. Triatoma infestans and T. infestans melanosoma presented with various heterochromatic blocks, with CMA3 + at the periphery and DAPI+ at the interior. Segments of rDNA 45S were found along the edges of the heterochromatic blocks, along with the presence of various nucleoli in each nucleus. Triatoma matogrossensis, T. rubrovaria and T. brasiliensis presented with only one heterochromatic block with the same characteristics (with the exception of T. brasiliensis, which presented with various dispersed CMA3 + blocks). In these species, only one nucleolus that was similar to the localization of the rDNA sites was found. All species presented with 2n = 20A + XY, with a decrease in size relative to the chromosomes. In the case of T. infestans melanosoma, the chromosomes were split into groups based on their relative sizes. The heterochromatin of this species presented... (Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:26:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2002-06-26Bitstream added on 2014-06-13T19:12:54Z : No. of bitstreams: 1 marchesin_src_me_sjrp.pdf: 635247 bytes, checksum: b4432ae0de06265a064ac1eae2f6d35f (MD5) / Foram analisados citogenéticamente seis espécies de Vespertilionidae dos gêneros Myotis, Lasiurus, Histiotus e Eptesicus. As metáfases obtidas de culturas de fibroblastos foram analisadas em coloração convencional, Ag-NOR, bandamento C e G e hibridização in situ fluorescente com sonda de seqüências teloméricas (TTAGGG)n humana. As espécies Myotis nigricans, Myotis riparius (2n=44; NF=50), Eptesicus brasiliensis (2n=50; NF=48) e Histiotus velatus (2n=50; NF=48) foram as que apresentaram o maior número de cromossomos; Lasiurus ega (2n=28; NF=48) e Lasiurus cinereus (2n=28; NF=48) apresentaram o menor número de cromossomos, o que evidencia variabilidade cariotípica ao nível morfológico. A coloração Ag-NOR evidenciou variação no número de nucléolos interfásicos e nos cromossomos com RONs. Em M. nigricans e M. riparius as marcações nos cromossomos portadores de RONs variaram em distribuição, número e tamanho. Em M. nigricans o número de cromossomos marcados variou de 7 a 9 e em M. riparius de 6 a 10. Nas duas espécies, as RONs foram observadas nas extremidades dos braços curtos e longos de cromossomos acrocêntricos. A variação no número deve estar refletindo a ativação diferencial de RONs, o que resulta uma variação no número e no tamanho dos nucléolos. Em M. nigricans o número de nucléolos observados variou de 01 a 09 e em M. riparius de 01 a 10. Além da ativação diferencial, a fusão nucleolar resultante do movimento, crescimento e aproximação dos nucléolos podem ser responsáveis pela variação observada. Em L. cinereus e H. velatus as RONs foram coincidentes com as constrições secundárias dos pares heteromórficos 11 e 13 em L. cinereus, e 15 em H. velatus. O padrão de bandas G obtidos para as espécies M. nigricans e M. riparius evidenciou a ocorrência de homologias cromossômicas entre elas. / Six species of four vespertilionid genera (Myotis, Lasiurus, Histiotus and Eptesicus) were cytogenetically analyzed. The metaphases obtained from fibroblast cultures were analyzed in conventional staining, Ag-NOR, C and G banding and fluorescent in situ hybridization with probe of human telomeric sequence (TTAGGG)n. The species Myotis nigricans (2n=44, NF=48), Myotis riparius (2n=44; NF=50), Eptesicus brasiliensis (2n=50; NF=48) and Histiotus velatus (2n=50; NF=48) showed the highest number of chromosomes; Lasiurus ega (2n=28; NF=48) and Lasiurus cinereus (2n=28; NF=48) showed the lowest number, indicating karyotypic variability on the morphologic level. Ag-NOR staining evinced variation in the number of interphasic nucleoli and in chromosomes with NORs. In M. nigricans and M. riparius, the chromosomal Ag-stained regions varied in distribution, number and size. In M. nigricans, the number of marked chromosomes varied between 7 and 9, and in M. riparius, the number varied between 6 and 10. In both species, the NORs were observed on the extremities of the short and long arms of acrocentric chromosomes. The variation in number might be reflecting of NORs differential activation, resulting in variation in the number and size of nucleoli. In M. nigricans, the number of observed nucleoli has varied between 01 and 09, and in M. riparius, between 01 and 10. Besides differential activation, the nucleolar fusion resulting from the movement, growth and approximation of nucleoli might be responsible for the observed variation. In L. cinereus and H. velatus, the NORs were coincident with the secondary constrictions of heteromorphic pairs 11 and 13 in L. cinereus, and pair 15 in H. velatus. The pattern for G banding obtained for the species M. nigricans and M. riparius evinced the occurrence of chromosomal homologies between them.

Made available in DSpace on 2014-06-11T19:26:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-02-24Bitstream added on 2014-06-13T18:29:26Z : No. of bitstreams: 1 faria_kc_me_sjrp.pdf: 1587104 bytes, checksum: 5b515af867e10b2a892710a2b48a4662 (MD5) / Para verificar a ocorrência de homologias cromossômicas entre espécies de Molossidae e Phyllostomidae (Chiroptera), foram realizadas análises comparativas do bandamento G e, hibridização in situ fluorescente genômica e telomérica nas espécies Carollia perspicillata (Carolliinae), Glossophaga soricina (Glossophaginae), P. hastatus (Phyllostominae), Sturnira lilium, Platyrrhinus lineatus e Artibeus planirostris (Stenodermatinae) de Phyllostomidae e, Molossus ater e Molossus molossus (Molossinae) de Molossidae. As análises do bandamento G evidenciaram que, à exceção de C. perspicillata, todas as demais espécies de Phyllostomidae compartilham homologias cromossômicas com as espécies de Molossidae. As espécies A. planirostris, P. lineatus e S. lilium apresentam 29 dos 32 braços cromossômicos de Molossus. Estas espécies compartilham dois cromossomos inteiros e os braços de oito cromossomos meta ou submetacêntricos destas espécies de Stenodermatinae apresentam homologias com cromossomos acrocêntricos e subtelocêntricos de Molossus. G. soricina também apresenta 29 braços cromossômicos de Molossus, sendo que três cromossomos inteiros são compartilhados e os braços de sete cromossomos de G. soricina apresentam homologias com cromossomos acrocêntricos e subtelocêntricos de Molossus. Todos os braços cromossômicos de P. hastatus apresentaram homologias com os cromossomos de Molossus. P. hastatus e Molossus compartilham cinco cromossomos inteiros e os braços de oito cromossomos de P. hastatus apresentam homologias com os cromossomos acrocêntricos e subtelocêntricos de Molossus. Estes resultados parecem sugerir uma proximidade maior das espécies de Molossidae com P. hastatus (Phyllostominae). Além de rearranjos do tipo fusões e inversões pericêntricas, outros rearranjos cromossômicos não determinados justificam as diferenças entre os cariótipos das espécies de... / To verify the occurrence of chromosome homologies between species of Molossidae and Phyllostomidae (Chiroptera), comparative analysis of the G-banding and, genomic and telomeric fluorescence in situ hibridization were accomplished in the species Carollia perspicillata (Carolliinae), Glossophaga soricina (Glossophaginae), Phyllostomus hastatus (Phyllostominae), Sturnira lilium, Platyrrhinus lineatus and Artibeus planirostris (Stenodermatinae) of Phyllostomidae and, Molossus ater and Molossus molossus (Molossinae) of Molossidae. The analysis of the G-banding evidenced that except C. perspicillata all the other species of Phyllostomidae share chromosome homologies with the species of Molossidae. The species A. planirostris, P. lineatus and S. lilium present 29 of the 32 chromosome arms of Molossus. These species share two whole chromosomes and the arms of eight meta or submetacentric chromosomes of these species of Stenodermatinae present homologies with acrocentric and subtelocentric chromosomes of Molossus. G. soricina also presents 29 chromosome arms of Molossus, in a way that three whole chromosomes are shared and the arms of seven chromosomes of G. soricina present homologies with acrocentric and subtelocentric chromosomes of Molossus. All of the chromosome arms of P. hastatus presented homologies with the chromosomes of Molossus. P. hastatus and Molossus share five whole chromosomes and the arms of eight chromosomes of P. hastatus present homologies with the acrocentrics and subtelocentrics chromosomes of Molossus. These results seem to suggest a larger proximity of the species of Molossidae with P. hastatus (Phyllostominae). Besides rearrangements like fusions and pericentric inversions, other not determined chomosome rearrangements justify the differences between the karyotype of the compared species of Phyllostomidae and Molossidae. The comparative genomic hybridizations with Molossus...(Complete abstract click electronic access below)

Made available in DSpace on 2014-06-11T19:35:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-02-19Bitstream added on 2014-06-13T20:07:16Z : No. of bitstreams: 1 alves_jcp_dr_botib.pdf: 3347522 bytes, checksum: 430f7c8a15cc08bc6af20d88aee1d9cc (MD5) / Foram analisadas onze espécies de peixes do gênero Characidium, Characidium cf. zebra, Characidium cf. gomesi, Characidium lauroi, Characidium oiticicai, Characidium lanei, Characidium pterostictum, Characidium schubarti, Characidium alipioi, Characidium sp1, Characidium sp2 e Characidium sp3 de diferentes bacias hidrográficas brasileiras, com o uso de técnicas citogenéticas básicas (coloração com Giemsa, localização das RONs pela marcação com nitrato de Prata e bandamento C) e moleculares (marcação por fluorocromos base-específicos, hibridação in situ fluorescente com sondas de DNAr 18S e 5S, com sondas teloméricas (TTAGGG)n e com sondas para histona H1 e também microdissecção, amplificação e hibridação in situ fluorescente com sondas produzidas a partir do cromossomo sexual W e dos cromossomos B). Todas as espécies apresentaram número diplóide de 2n=50 cromossomos, com predominância dos cromossomos dos tipos meta e submetacêntricos, além da ocorrência de cromossomos supranumerários em C. pterostictum, C. oiticicai, C. cf. gomesi e Characidium sp3. Foi observada também a ocorrência de um sistema ZZ-ZW de cromossomos sexuais representado pelo par heteromórfico número 2 em todas as espécies, com exceção apenas de Characidium cf. zebra, que não apresentou cromossomos sexuais diferenciados. O DNAr 5S foi localizado em diferentes cromossomos entre estas espécies, mas sempre em posição intersticial dos cromossomos, reforçando a idéia de que esta localização cromossômica poderia representar alguma vantagem relacionada à organização destes genes no genoma. As RONs, identificadas pela prata, pela CMA3 e pela sonda de DNAr 18S, foram sempre localizadas em compartimentos cromossômicos distintos do DNAr 5S e estão diretamente relacionadas ao processo de diferenciação dos cromossomos Z e W,... / Eleven species of fish of the genus Characidium comprised by Characidium cf. zebra, Characidium cf. gomesi, Characidium lauroi, Characidium oiticicai, Characidium lanei, Characidium pterostictum, Characidium schubarti, Characidium alipioi, Characidium sp1, Characidium sp2, and Characidium sp3 from different Brazilian hydrographic basins were analyzed using basic cytogenetic (coloration with Giemsa, localization of NORs for silver nitrate marking and C-banding) and molecular techniques (for base-specific fluorochrome markings, fluorescent in situ hybridization with 18S and 5S rDNA probes, telomere probes (TTAGGG)n, and H1 histone, as well as microdissection, amplification and in situ fluorescent hybridization using probes prepared from both sex W and B chromosome). All the species presented a diploid number of 2n=50 chromosomes, with a predominance of the meta- and submetacentric types, besides the occurrence of supranumerary chromosomes in C. pterostictum, C. oiticicai, C. cf. gomesi, and Characidium sp3. The occurrence of a ZZ-ZW sex chromosome system represented by the heteromorphic pair number 2 in all species was observed, with the exception of Characidium cf. zebra, which did not presented differentiated sex chromosomes. The 5S rDNA marks were observed in different chromosomes among these species, but always located in an interstitial position, strengthening the idea that this chromosome location might represent some advantage related to the organization of these genes in the genome. NORs identified using Silver and CMA3, staining and 18S rDNA probe have always been located in distinct chromosome compartments when compared to 5S rDNA, showed to be directly related to the Z and W chromosome differentiation process, and is considered to play an important role in their evolution, considering that they could... (Complete abstract click electronic access below)

Orientador: Eliana Morielle Versute / Banca: Shirley Maria Recco Pimentel / Banca: Guaracy Tadeu Rocha / Resumo: Para verificar a ocorrência de homologias cromossômicas entre espécies de Molossidae e Phyllostomidae (Chiroptera), foram realizadas análises comparativas do bandamento G e, hibridização in situ fluorescente genômica e telomérica nas espécies Carollia perspicillata (Carolliinae), Glossophaga soricina (Glossophaginae), P. hastatus (Phyllostominae), Sturnira lilium, Platyrrhinus lineatus e Artibeus planirostris (Stenodermatinae) de Phyllostomidae e, Molossus ater e Molossus molossus (Molossinae) de Molossidae. As análises do bandamento G evidenciaram que, à exceção de C. perspicillata, todas as demais espécies de Phyllostomidae compartilham homologias cromossômicas com as espécies de Molossidae. As espécies A. planirostris, P. lineatus e S. lilium apresentam 29 dos 32 braços cromossômicos de Molossus. Estas espécies compartilham dois cromossomos inteiros e os braços de oito cromossomos meta ou submetacêntricos destas espécies de Stenodermatinae apresentam homologias com cromossomos acrocêntricos e subtelocêntricos de Molossus. G. soricina também apresenta 29 braços cromossômicos de Molossus, sendo que três cromossomos inteiros são compartilhados e os braços de sete cromossomos de G. soricina apresentam homologias com cromossomos acrocêntricos e subtelocêntricos de Molossus. Todos os braços cromossômicos de P. hastatus apresentaram homologias com os cromossomos de Molossus. P. hastatus e Molossus compartilham cinco cromossomos inteiros e os braços de oito cromossomos de P. hastatus apresentam homologias com os cromossomos acrocêntricos e subtelocêntricos de Molossus. Estes resultados parecem sugerir uma proximidade maior das espécies de Molossidae com P. hastatus (Phyllostominae). Além de rearranjos do tipo fusões e inversões pericêntricas, outros rearranjos cromossômicos não determinados justificam as diferenças entre os cariótipos das espécies de...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: To verify the occurrence of chromosome homologies between species of Molossidae and Phyllostomidae (Chiroptera), comparative analysis of the G-banding and, genomic and telomeric fluorescence in situ hibridization were accomplished in the species Carollia perspicillata (Carolliinae), Glossophaga soricina (Glossophaginae), Phyllostomus hastatus (Phyllostominae), Sturnira lilium, Platyrrhinus lineatus and Artibeus planirostris (Stenodermatinae) of Phyllostomidae and, Molossus ater and Molossus molossus (Molossinae) of Molossidae. The analysis of the G-banding evidenced that except C. perspicillata all the other species of Phyllostomidae share chromosome homologies with the species of Molossidae. The species A. planirostris, P. lineatus and S. lilium present 29 of the 32 chromosome arms of Molossus. These species share two whole chromosomes and the arms of eight meta or submetacentric chromosomes of these species of Stenodermatinae present homologies with acrocentric and subtelocentric chromosomes of Molossus. G. soricina also presents 29 chromosome arms of Molossus, in a way that three whole chromosomes are shared and the arms of seven chromosomes of G. soricina present homologies with acrocentric and subtelocentric chromosomes of Molossus. All of the chromosome arms of P. hastatus presented homologies with the chromosomes of Molossus. P. hastatus and Molossus share five whole chromosomes and the arms of eight chromosomes of P. hastatus present homologies with the acrocentrics and subtelocentrics chromosomes of Molossus. These results seem to suggest a larger proximity of the species of Molossidae with P. hastatus (Phyllostominae). Besides rearrangements like fusions and pericentric inversions, other not determined chomosome rearrangements justify the differences between the karyotype of the compared species of Phyllostomidae and Molossidae. The comparative genomic hybridizations with Molossus...(Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2015-03-26T13:42:17Z (GMT). No. of bitstreams: 1 texto completo.pdf: 4676037 bytes, checksum: 95dde20b76c33bfd09f530eb8a65e6e5 (MD5) Previous issue date: 2010-07-19 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The tribe Attini consists of a monophyletic group that includes about 230 species in 14 genera. Different biological substrate are utilized by these ants for cultivation of the symbiotic fungus on which they feed and are necessarily dependent. This tribe includes the leaf-cutting ants (Atta Fabricius and Acromyrmex Mayr) that are known as important agricultural pests. The usage of cytogenetics in the family Formicidae has made significant contributions in the study of more than 750 ant species. Only 10% of Attini&#8217;s species have some sort of cytogenetic data available. This work aimed at cytogenetically studying six Acromyrmex species and seven species of the tribe Attini divided into four genera: Apterostigma Mayr, Mycocepurus Forel, Sericomyrmex Mayr and Trachymyrmex Forel. Some of the species were also submitted to banding techniques. The karyotypes observed were: Apterostigma madidiense Weber (n=23, 7m + 10sm + 5st + 1a), Apterostigma steigeri Santschi (2n=22, 20m + 2sm), Mycocepurus goeldii (2n=8, 4m + 4sm), Sericomyrmex sp. (2n=50, 44m + 6 sm; n=25, 22m + 3 sm), Trachymyrmex fuscus Emery (2n=18, 16m + 2sm; n=9, 8m + 1sm), Trachymyrmex relictus Borgmeier (2n=20m, n=10m) and Trachymyrmex sp. (2n=22, 18m + 4sm). A size polymorphism on a short arm of a submetacentric pair from Trachymyrmex fuscus was also pointed out. The possible causes of chromosomal segment duplication were discussed. All studied species of the genus Acromyrmex presented 2n=38. Each species showed a different karyotype in relation to morphology (A. balzani: 12m + 10sm + 14st + 2a; A. coronatus: 12m + 12sm + 12st + 2a; A. disciger: 10m + 12sm + 14st + 2a; A. niger: 12m + 18sm + 6st + 2a; A. rugosus: 16m + 12sm + 8st + 2a; A. echinatior: 8m + 6sm + 14st + 10a), in the distribution of heterocromatin (C banding) and GC rich regions (CMA3). For three species (A. coronatus, A. disciger, A. niger) the first subtelocentric pair was the bearer of ribosomal genes. Acromyrmex species presented stability in the number of chromosome with differences in the karyotype. The results suggest that many chromosomal rearrangements such as translocations, growth of heterochromatin and inversion may have occurred during their differentiation, contributing to the karyotype variability found. / A tribo Attini é um grupo monofilético que inclui mais de 230 espécies agrupadas em 14 gêneros. Nesta tribo estão incluídas as formigas cortadeiras (Atta e Acromyrmex), consideradas importantes pragas agrícolas. A utilização da citogenética na família Formicidae tem mostrado importante contribuição nas mais de 750 espécies de formigas estudadas. Os dados citogenéticos são reportados para 10% das espécies da tribo Attini. O presente trabalho teve como objetivo o estudo citogenético de seis espécies do gênero Acromyrmex e de sete espécies de Attini distribuídas em quatro gêneros: Apterostigma, Mycocepurus, Sericomyrmex e Trachymyrmex. Parte das espécies foi submetida a técnicas de bandamentos cromossômicos. Os cariótipos observados foram: Apterostigma madidiense Weber (n=23, 7m + 10sm + 5st + 1a), A. steigeri Santschi (2n=22, 20m + 2sm), Mycocepurus goeldii (Forel) (2n=8, 4m + 4sm), Sericomyrmex sp. (2n=50, 44m + 6sm; n=25, 22m + 3sm), Trachymyrmex fuscus Emery (2n=18, 16m + 2sm; n=9, 8m + 1sm), T. relictus Borgmeier (2n=20m, n=10m) e Trachymyrmex sp. (2n=22, 18m + 4sm). Trachymyrmex fuscus apresentou polimorfismo de tamanho no braço curto do par submetacêntrico. As possíveis causas da duplicação do segmento cromossômico são discutidas. As seis espécies do gênero Acromyrmex apresentaram 2n=38 cromossomos. Cada espécie mostrou um cariótipo diferente em relação à morfologia (A. balzani: 12m + 10sm + 14st + 2a; A. coronatus: 12m + 12sm + 12st + 2a; A. disciger: 10m + 12sm + 14st + 2a; A. niger: 12m + 18sm + 6st + 2a; A. rugosus: 16m + 12sm + 8st + 2a; A. echinatior: 8m + 6sm + 14st + 10a) e variações na distribuição de heterocromatina (banda C) e regiões ricas em GC (CMA3). Em três espécies (A. coronatus, A. disciger, A. niger) o par subtelocêntrico de maior tamanho foi o portador de genes ribossomais. As espécies do gênero Acromyrmex apresentaram estabilidade no número cromossômico com diferenças no cariótipo. Isto sugere que rearranjos do tipo translocações, crescimento de heterocromatina e inversão devem ter ocorrido durante a evolução das espécies deste gênero, levando a modificações nos cariótipos das diferentes espécies.