Meiotic chromosomes and nucleolar behavior in testicular cells of the grassland spittlebugs Deois flavopicta, Mahanarva fimbriolata and Notozulia entreriana (Hemiptera, Auchenorrhyncha)

Spittlebugs annually infest pastures and cause severe damage, representing a serious problem for the tropical American beef cattle industry. Spittlebugs are an important biotic constraint to forage production and there is a lack of cytogenetic data for this group of insects. For these reasons, we conducted this work, in which the spermatogenesis and nucleolar behavior of Deois flavopicta, Mahanarva fimbriolata and Notozulia entreriana were studied. The males possessed testes in the shape of a “bunch of grapes”; a variable number of testicular lobes per individual and polyploid nuclei composed of several heteropycnotic bodies. A heteropycnotic area was located in the periphery of the nucleus (prophase I); the chiasmata were terminal or interstitial; metaphases I were circular or linear and anaphase showed late migration of the sex chromosome. The chromosome complement had 2n = 19, except for N. entreriana (2n = 15); the spermatids were round with heteropycnotic material in the center and elongated with conspicuos chromatin. The analysis of testes after silver nitrate staining showed polyploid nuclei with three large and three smaller nucleolar bodies. Early prophase cells had an intensely stained nucleolar body located close to the chromatin and another less evident body located away from the chromatin. The nucleolar bodies disintegrated during diplotene. Silver staining occurred in two autosomes, in terminal and subterminal locations, the latter probably corresponding to the nucleolus organizer regions (NORs). The spermatids were round with a round nucleolar body and silver staining was observed in the medial and posterior region of the elongated part of the spermatid head

Relacionamento filogenético entre espécies pertencentes às famílias Belostomatidae, Gelastocoridae, Gerridae, Notonectidae, Veliidae (Hemiptera: Heteroptera) e Cercopidae (Hemiptera:Auchenorrhyncha)

O presente trabalho teve por objetivo principal contribuir com informações relevantes a cerca de espécies pertencentes a percevejos aquáticos e cigarrinha das pastagens neotropicais brasileiras. As relações filogenéticas entre espécies das famílias Belostomatidae, Gelastocoridae, Gerridae, Notonectidae e Veliidae (Heteroptera) e Cercopidae (Auchenorrhyncha) vêm sendo bastante discutidas, devido ao grande número de espécies pertencentes a esses dois grupos, quanto a sua monofilia e proximidade entre os táxons. Neste trabalho, foram realizadas análises de variabilidade genética, composição nucleotídica e relacionamentos filogenéticos baseada em aspectos citogenéticos (número de autossomos, sistema cromossômico do sexo, presença ou ausência de m cromossomos e cromossomos Y), ecológicos (habitat e hábito alimentar), moleculares (marcadores COI, 16S e 28S) e morfológicos (morfologia dos testículos) combinados e separadamente. Por meio das análises foi possível verificar que os táxons estudados de Cercopidae (Cicadomorpha, Auchenorrhyncha) e das infraordens Gerromorpha e Nepomorpha de Heteroptera apresentaram se monofiléticos. Diante dos relacionamentos observados, foi possível propor também, que o estado ancestral para o sistema cromossômico do sexo foi o X0, enquanto que para o número de autossomos não foi possível estabelecer quais eventos estão ocorrendo, se de fissão ou fusão. Os resultados apresentados são de grande importância em virtude da escassez de dados de percevejos aquáticos e cigarrinha das pastagens,principalmente em análises combinadas, contendo dados moleculares, citogenéticos, ecológicos e morfológicos. Porém, ainda é necessária a análise de um maior número de táxons e de regiões gênicas para corroborar tais achadosThe present study aimed at contributing with relevant information about the species of aquatic bugs and spittlebugs in Brazilian neotropical pastures. Phylogenetic relationships among species of the families Belostomatidae, Gelastocoridae, Gerridae, Notonectidae and Veliidae (Heteroptera) and Cercopidae (Auchenorrhyncha) have been widely discussed, due to the large number of species belonging to these two groups, as their monophyly and closeness among taxa. In this study, we performed analyzes of genetic variability, nucleotide composition and phylogenetic relationships based on cytogenetic aspects (number of autosomes, sex chromosome system, presence or absence of m-chromosomes and Y chromosomes), ecological (habitat and feeding habits), molecular (COI, 16S and 28S markers) and morphological (morphology of the testes) combined and separately. Through the analysis we found that the taxa studied to Cercopidae (Cicadomorpha, Auchenorrhyncha) and infraorders Gerromorpha and Nepomorpha of Heteroptera showed up monophyletic. Given the observed relationships, it was also possible to propose that the ancestral state for the sex chromosome system was the X0, while the number of autosomes was not possible to establish which events are occurring fission or fusion. The results presented are of great importance due to the scarcity of data from aquatic bugs and spittlebugs, mainly in combined analyzes, data containing molecular, cytogenetic, morphological and ecological. However, it is still necessary to analyze a greater number of taxa and gene regions to corroborate these finding

Espermatogênese e comportamento nucleolar em machos de Heteoptera aquáticos

Os aspectos da espermatogênese e do comportamento nucleolar foram analisados em Brachymetra albinerva, Cylindrostethus palmaris, Halobatopsis platensis, Limnogonus aduncus (Gerridae), Martarega sp. (Notonectidae), Rhagovelia whitei e Rhagovelia sp. (Veliidae). Os testículos são arredondados (Veliidae), alongados (Gerridae) ou espiralados (Notonectidae) e apresentam membrana transparente recobrindo-os. O complemento cromossômico encontrado foi de 2n = 23 (22A + X0, L. aduncus e R. sp.); 25 (24A + X0, B. albinerva e H. platensis); 26 (22A + 2m + XY, Martarega sp.); 29 (28A + X0, C. palmaris) ou 39 (38A + X0, R. whitei) cromossomos, sendo que a única espécie com sistema cromossômico do sexo diferente foi M. sp., que apresentou sistema XY, além de ser, também, a única espécie com m-cromossomos. O comportamento meiótico de todas as espécies foi semelhante, isto é, apresentaram: cromossomos holocêntricos, material heteropicnótico na prófase; quiasmas intersticiais e/ou terminais; primeira divisão reducional para os autossomos e o inverso para os cromossomos sexuais. A única diferença observada foi com relação ao tamanho extremamente maior das células de M. sp., em todas as fases da espermatogênese. Com relação ao comportamento nucleolar as espécies não apresentaram diferenças, somente M. sp. que possui nucléolos maiores que as demais espécies. A única espécie na qual foi possível identificar com clareza a região da RON foi L. aduncus, na região terminal de um autossomo. Confirmou-se, também, através da espécie L. aduncus, que as associações teloméricas não ocorrem ao acaso. Nas demais espécies a marcação da RON foi bastante discreta, não sendo possível afirmar com clareza onde ela está localizada.The aspects of spermatogenesis and nucleolar behaviour were analyzed in Brachymetra albinerva, Cylindrostethus palmaris, Halobatopsis platensis, Limnogonus aduncus (Gerridae), Martarega sp. (Notonectidae), Rhagovelia whitei and Rhagovelia sp. (Veliidae). The testicles are rounded (Veliidae), elongated (Gerridae) or spiral (Notonectidae) and have a transparent membrane covering them. The complement chromosome was 2n = 23 (22A + X0, L. aduncus and R. sp.), 25 (24A + X0, B. albinerva and H. platensis), 26 (22A + 2m + XY, Martarega sp.), 29 (28A + X0, C. palmaris) or 39 (38A + X0, R. whitei) chromosomes, and the only specie with different sex chromosome system was M. sp., which presented XY system and m-chromosomes. The meiotic behavior of all species was similar: holocentric chromosomes, heteropicnotic material at prophase; chiasmas interstitial and/or terminal; first reductional division for the autosomes and the reverse for the sex chromosomes. The only difference observed was related to the very largest size of the cells M. sp. in all stages of spermatogenesis. With regard to the nucleolar behavior, the species did not show differences, only M. sp. which has nucleoli larger than the other species. The only species in which it was clearly possible to identify the region of NOR was L. aduncus, in the region of a terminal autosome. It was also confirmed that the telomeric associations do not occur at random. In other species the marking was very discreet, no one can clearly say where NOR is located.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Morphological patterns of the heteropycnotic chromatin and nucleolar material in meiosis and spermiogenesis of some Pentatomidae (Heteroptera)

Pentatomidae is a family of Heteroptera which includes several agriculture pests that have had different aspects of their meiosis and spermiogenesis analyzed. In the present study we analyzed the morphological patterns of the heteropycnotic chromatin and the nucleolar material of Mormidea v-luteum, Oebalus poecilus and Oebalus ypsilongriseus. The three species presented multilobate testes, with three lobes in M. v-luteum and four in the Oebalus species. A karyotype with 2n = 14 chromosomes (12A + XY) was observed in the three species. Several characteristics were common to the three species, such as the absence of a testicular harlequin lobe (a lobe which produces different types of spermatozoa, previously considered a general characteristic of this family), late migration of the sex chromosomes and semi-persistence of the nucleolus. The three species also shared some characteristics regarding the patterns of the heteropycnotic chromatin and nucleolar material, but differed in others mainly related to the location of the heteropycnotic chromatin in the spermatids and the morphology and distribution of the nucleolar material at zygotene. The differences were always between species from different genera, suggesting a relationship with their genetic divergence.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Regulation of <i>VEGFA</i>, <i>KRAS</i>, and <i>NFE2L2</i> Oncogenes by MicroRNAs in Head and Neck Cancer

Mutations and alterations in the expression of VEGFA, KRAS, and NFE2L2 oncogenes play a key role in cancer initiation and progression. These genes are enrolled not only in cell proliferation control, but also in angiogenesis, drug resistance, metastasis, and survival of tumor cells. MicroRNAs (miRNAs) are small, non-coding regulatory RNA molecules that can regulate post-transcriptional expression of multiple target genes. We aimed to investigate if miRNAs hsa-miR-17-5p, hsa-miR-140-5p, and hsa-miR-874-3p could interfere in VEGFA, KRAS, and NFE2L2 expression in cell lines derived from head and neck cancer (HNC). FADU (pharyngeal cancer) and HN13 (oral cavity cancer) cell lines were transfected with miR-17-5p, miR-140-5p, and miR-874-3p microRNA mimics. RNA and protein expression analyses revealed that miR-17-5p, miR-140-5p and miR-874-3p overexpression led to a downregulation of VEGFA, KRAS, and NFE2L2 gene expression in both cell lines analyzed. Taken together, our results provide evidence for the establishment of new biomarkers in the diagnosis and treatment of HNC

Meiotic behavior of 18 species from eight families of terrestrial Heteroptera

Insects of the suborder Heteroptera are known for their odor, for being pests, or for being disease carriers. To gain better insight into the cytogenetic characteristics of heteropterans, 18 species of terrestrial Heteroptera belonging to eight families were studied. The presence of heteropycnotic corpuscles during prophase I, terminal or interstitial chiasmas, telomeric associations between chromosomes, ring disposals of autosomes during metaphase, and late migrations of the sex chromosomes during anaphase were analyzed. These features showed identical patterns to other species of Heteroptera previously described in the literature. Another studied characteristic was chromosome complements. The male chromosome complements observed were 2n = 12 chromosomes [10A + XY, Galgupha sidae (Amyot & Serville) (Corimelaenidae) and Pachycoris torridus (Scopoli) (Scutelleridae)]; 2n = 13 [10A + 2m + X0, Harmostes serratus (Fabricius), Harmostes apicatus (Stål), Jadera haematoloma (Herrich-Schaeffer), Jadera sanguinolenta (Fabricius), Jadera sp. (Rhopalidae)], and Neomegalotomus parvus (Westwood) (Alydidae); 2n = 13 [12A + X0, Stenocoris furcifera (Westwood) (Alydidae); 2n = 14 [12A + XY, Dictyla monotropidia (Stål) (Tingidae)]; 2n = 19 [18A + X0, Acanonicus hahni (Stål) (Coreidae)]; 2n = 21 [18A + 2m + X0, Acanthocephala sp. (Dallas) (Coreidae)]; 2n = 27 [24A + 2m + X0, Anisoscelis foliacea marginella (Dallas) (Coreidae)]; 2n = 18 [16A + XY, Oncopeltus fasciatus (Dallas) (Lygaeidae)]; 2n = 17 [14A + X1X2Y, Oxycarenus hyalinipennis (Costa) (Lygaeidae)]; 2n = 16 [12A + 2m + XY, Pachybrachius bilobatus (Say) (Lygaeidae)]; 2n = 26 [24A + XY, Atopozelus opsinus (Elkins) (Reduviidae)]; and 2n = 27 [24A + X1X2Y, Doldina carinulata (Stål) (Reduviidae)]. The diversity of the cytogenetic characteristics of Heteroptera was reflected in the 18 studied species. Thus, this study extends the knowledge of these characteristics, such as the variations related to chromosome complements, sex chromosome systems, and meiotic behavior