Comportamento e organização dos cromossomos holocêntricos de heterópteros da região Sul do Brasil baseados em sequências repetitivas DNA, meiose e análise ultraestrutural

The species of the suborder Heteroptera have holokinetic chromosomes, variation in chromosome number, inverted/achiasmatic meiosis in the sex chromosomes and accumulation of heterochromatin predominantly in chromosome ends. In the 30 species analyzed of the infraorders Pentatomomorpha and Cimicomorpha, variations in chromosome numbers and asymmetrical karyotypes were observed, especially in Reduviidae. The C-CMA3/DAPI banding also showed that there is variability in the distribution of heterochromatic bands between autosomes and alossomos, however, the predominant location of heterochromatin were in the chromosome terminals. The 18S rDNA sites were located mainly in the terminal regions, with a tendency to distributed among the autosomes in Pentatomomorpha, whereas in species Cimicomorpha there was greater variation between autosomes and alossomos. To a more detailed study of the origin and organization of families of repetitive DNA, Triatoma infestans was chosen as a model. This study showed the two sequences of AT-rich satellite DNA that predominate on the ends of chromosomes, are composed of short motifs with 79 bp and 33 bp, which were possibly originated from transposable elements known as giant Polintons. Cytogenetic comparisons of all samples studied in this work showed some trends, such as the predominance of the sexual system XY/XX, the preferred location of heterochromatin and 18S rDNA sites on the ends of chromosomes and the occurrence of holokinetic chromosomes. However, changes in the organization and asymmetry of karyotypes observed in each group show a relative dynamic in the genomes of these heteropteranAs espécies da subordem Heteroptera possuem cromossomos holocinéticos, variação do número cromossômico, meiose invertida e aquiasmática nos cromossomos sexuais e acúmulo de heterocromatina predominantemente nas extremidades cromossômicas. Das 30 espécies analisadas das infraordens Pentatomomorpha e Cimicomorpha, foram observadas variações nos números cromossômicos e cariótipos assimétricos, sobretudo em Reduviidae. O bandamento C-CMA3/DAPI também mostrou que há variabilidade na distribuição de bandas heterocromáticas entre autossomos e alossomos, contudo, a localização da heterocromatina predominou nos terminais cromossômicos. Os sítios de DNAr 18S foram localizados principalmente nas regiões terminais, com tendência à distribuição entre os autossomos nos Pentatomomorpha, enquanto que nas espécies de Cimicomorpha houve uma maior variação entre autossomos e alossomos. Para um estudo mais aprofundado sobre a origem e a organização de famílias de DNA repetitivo, foi escolhida Triatoma infestans como modelo. Este estudo mostrou as duas sequências de DNA satélite ricas em AT que predominam nas regiões terminais dos cromossomos, são compostas por motivos curtos com 79 bp e 33 bp de comprimento, que foram originadas possivelmente de elementos transponíveis gigantes conhecidos como Polintons. As comparações citogenéticas de todas as amostras estudadas neste trabalho mostraram algumas tendências, tais como a predominância do sistema sexual XY/XX, a localização preferencial da heterocromatina e dos sítios de DNAr 18S nas regiões terminais dos cromossomos e a ocorrência de cromossomos holocinéticos. Contudo, as variações na organização e assimetria dos cariótipos observadas de cada grupo mostram uma relativa dinâmica nos genomas desses heterópterosCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Análise citogenética molecular em túbulos seminíferos de triatomíneos (Triatominae, Heteroptera)

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)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

The conservation of number and location of 18S sites indicates the relative stability of rDNA in species of Pentatomomorpha (Heteroptera)

Fluorescent in situ hybridization (FISH) with rDNA probes has been used for comparative cytogenetics studies in different groups of organisms. Although heteropterans are a large suborder within Hemiptera, studies using rDNA are limited to the infraorder Cimicomorpha, in which rDNA sites are present in the autosomes or sex chromosomes. We isolated and sequenced a conserved 18S rDNA region of Antiteuchus tripterus (Pentatomidae) and used it as a probe against chromosomes of 25 species belonging to five different families of Pentatomomorpha. The clone pAt05, with a length of 736 bp, exhibited a conserved stretch of 590 bp. FISH analysis with the probe pAt05 always demonstrated hybridization signals in sub-terminal positions, except for Euschistus heros. Apparently, there is a tendency for 18S rDNA sites to locate in autosomes, except for Leptoglossus gonagra and Euryophthalmus rufipennis, which showed signals in the m-and sex chromosomes, respectively. Although FISH has produced evidence that rearrangements are involved in rDNA repositioning, whether in different autosomes or between sex and m-chromosomes, we have no conclusive evidence of what were the pathways of these rearrangements based on the evolutionary history of the species studied here. Nevertheless, the diversity in the number of species analyzed here showed a tendency of 18S rDNA to remain among the autosomes.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Repetitive DNAs in Melipona scutellaris (Hymenoptera: Apidae: Meliponidae): chromosomal distribution and test of multiple heterochromatin amplification in the genus

International audienceAbstractMelipona bees are remarkable due to the high contrast in heterochromatin amounts, making this group interesting for studying repetitive DNA amplification. Here, we performed the first efforts for the chromosomal localization of different repetitive DNAs in M. (Michmelia) scutellaris and tested for unique or multiple heterochromatin amplification in Melipona subgenera. Our data revealed enrichment of repetitive DNAs in chromosomal heterochromatic arms demonstrated by C0t-DNA and DOP-PCR probe hybridization, although microsatellites and multigene families were located at terminal euchromatic regions. Analysis using C0t-DNA probe from M. scutellaris showed positive hybridization only in Michmelia species, suggesting monophyletic amplification and sharing of heterochromatin sequences between species. However, the subgenus Melikerria, with a high amount of heterochromatin, probably underwent independent heterochromatin amplification or experienced sequence modification

Origin and distribution of AT-rich repetitive DNA families in Triatoma infestans (Heteroptera)

Triatoma infestans, one of the most important vectors of Trypanosoma cruzi, is very interesting model, because it shows large interpopulation variation in the amount and distribution of heterochromatin. This polymorphism involved the three large pairs up to almost all autosomal pairs, including the sex chromosomes. To understand the dynamics of heterochromatin variation in T. infestans, we isolated the AT-rich satDNA portion of this insect using reassociation kinetics (C(0)t), followed by cloning, sequencing and FISH. After chromosome localization, immunolabeling with anti-5-methylcytosine, anti-H4K5ac and anti-H3K9me2 antibodies was performed to determine the functional characteristics of heterochromatin. The results allowed us to reorganize the karyotype of T. infestans in accordance with the distribution of the families of repetitive DNA using seven different markers. We found that two arrays with lengths of 79 and 33 bp have a strong relationship with transposable element sequences, suggesting that these two families of satDNA probably originated from Polintons. The results also allowed us to identify at least four chromosome rearrangements involved in the amplification/dispersion of AT-rich satDNA of T. infestans. These data should be very useful in new studies including those examining the cytogenomic and population aspects of this very important species of insect. (C) 2014 Elsevier B.V. All rights reserved.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Heterochromatin base pair composition and diversification in holocentric chromosomes of kissing bugs (Hemiptera, Reduviidae)

Submitted by Sandra Infurna ([email protected]) on 2017-03-07T15:05:03Z No. of bitstreams: 1 cleber_galvao_etal_IOC_2016.pdf: 2748793 bytes, checksum: 860f52373d5ea4435f440b97e2e4f1ae (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2017-03-07T15:15:15Z (GMT) No. of bitstreams: 1 cleber_galvao_etal_IOC_2016.pdf: 2748793 bytes, checksum: 860f52373d5ea4435f440b97e2e4f1ae (MD5)Made available in DSpace on 2017-03-07T15:15:15Z (GMT). No. of bitstreams: 1 cleber_galvao_etal_IOC_2016.pdf: 2748793 bytes, checksum: 860f52373d5ea4435f440b97e2e4f1ae (MD5) Previous issue date: 2016Universidade Estadual Paulista. Instituto de Biociências. Departamento de Biologia. Rio Claro, SP, Brasil.Universidad de la República. Facultad de Ciencias. Sección Genética Evolutiva. Montevideo, Uruguay.Universidade Estadual de Londrina. Centro de Ciências Biológicas. Departamento de Biologia Geral. Londrina, PR, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório Nacional e Internacional de Referência em Taxonomia de Triatomíneos, Rio de Janeiro, RJ, Brasil.Universidad de la República. Facultad de Ciencias. Sección Genética Evolutiva. Montevideo, Uruguay.The subfamily Triatominae (Hemiptera, Reduviidae) includes 150 species of blood-sucking insects, vectors of Chagas disease or American trypanosomiasis. Karyotypic information reveals a striking stability in the number of autosomes. However, this group shows substantial variability in genome size, the amount and distribution of C-heterochromatin, and the chromosome positions of 45S rDNA clusters. Here, we analysed the karyotypes of 41 species from six different genera with C-fluorescence banding in order to evaluate the base-pair richness of heterochromatic regions. Our results show a high heterogeneity in the fluorescent staining of the heterochromatin in both autosomes and sex chromosomes, never reported before within an insect subfamily with holocentric chromosomes. This technique allows a clear discrimination of the heterochromatic regions classified as similar by C-banding, constituting a new chromosome marker with taxonomic and evolutionary significance. The diverse fluorescent patterns are likely due to the amplification of different repeated sequences, reflecting an unusual dynamic rearrangement in the genomes of this subfamily. Further, we discuss the evolution of these repeated sequences in both autosomes and sex chromosomes in species of Triatominae

Spermatogenesis in Triatoma williami Galvao, Souza and Lima (1965) (Hemiptera, Triatominae)

Cytogenetics has proven to be an important tool in the study of triatomine taxonomy. Triatoma williami is a triatomine that has been classified within the Matogrossensis subcomplex. In this study, the cytogenetic technique of lacto-aceto-orcein was used to confirm the karyotype of this species, which was found to be 2n = 22 (20A + XY). In this study, metaphases I and II were analyzed and the heteropyknotic pattern during the spermatogenesis and spermiogenesis was described, with results that corroborated the classification of T. williami in the Matogrossensis subcomplex.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Cytogenetic characterization reveals differences in nuclear organization of cystic cells among Brazilian species of Triatoma (Heteroptera, Reduviidae)

Cytogenetic studies in triatomines have described the occurrence of holokinetic chromosomes, heterochromatin distribution and the location of rDNA (ribosomal DNA) sites, but few aspects of nuclear organization in this group have been discussed. We have focused on ultrastructural and cytogenetic features and differences in cystic cells of seminiferous tubules between five species of Triatoma. Cystic cells showed evidence of polyploidy events and heterochromatic blocks appeared predominantly in the central region of the nuclei. Cytogenetic analyses showed that there was variation in chromocenter number between species, and that the central regions were AT-rich [DAPI(+) (4',6-diamidino-2-phenylindole(+))], whereas the periphery was CG-rich (CMA(+)). Another characteristic was the distribution of 45S rDNA, which differed according to the chromosomal location of this sequence. In all we have compared aspects of nuclear organization, polyploidy, heterochromatin, rDNA site distribution and methylation levels, as well as the relationships between five species of Triatoma from a cystic cell perspective.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES