Immunohistochemical detection of l cells in gastrointestinal tract mucosa of patients after surgical treatment for control of type 2 diabetes mellitus / Detecção imunohistoquímica de células l na mucosa do trato gastrointestinal de pacientes após tratamento cirúrgico para controle de diabetes mellitus tipo 2

ABSTRACT - BACKGROUND: Type 2 diabetes mellitus (T2DM) is a disease of global impact that has led to an increase in comorbidities and mortality in several countries. Immunoexpression of the incretin hormones such as glucagon-like peptide-1 (GLP-1) and peptide YY (3-36) (PYY3-36) can be used as a scorer in the gastrointestinal tract to analyze L-cell activity in response to T2DM treatment. OBJECTIVE: This study aimed to investigate the presence, location, and secretion of L cells in the small intestine of patients undergoing the form of bariatric surgery denominated adaptive gastroenteromentectomy with partial bipartition. METHODS: Immunohistochemical assays, quantitative real-time polymerase chain reaction (qPCR), and Western blot analysis were performed on samples of intestinal mucosa from patients with T2DM in both the preoperative and postoperative periods. RESULTS: All results were consistent and indicated basal expression and secretion of GLP-1 and PYY3-36 incretins by L cells. A greater density of cells was demonstrated in the most distal portions of the small intestine. No significant difference was found between GLP-1 and PYY3-36 expression levels in the preoperative and postoperative periods because of prolonged fasting during which the samples were collected. CONCLUSION: The greater number of L cells in activity implies better peptide signaling, response, and functioning of the neuroendocrine system.

RESUMO - RACIONAL: O diabetes tipo 2 (DM2) é uma doença de impacto mundial que tem levado ao aumento de comorbidades e mortalidade em vários países. A imunoexpressão dos hormônios incretínicos glp-1 e pyy3-36, pode ser usada como marcador no trato gastrointestinal para analisar a atividade da célula L em resposta ao tratamento do DM2. OBJETIVO: O presente estudo teve como objetivo investigar a presença, localização e secreção de células L no intestino delgado de pacientes submetidos à forma de cirurgia bariátrica denominada gastroenteromentectomia adaptativa com bipartição parcial. MÉTODOS: Ensaios imunohistoquímicos, reação quantitativa em cadeia de polimerase em tempo real (qPCR) e análise de manchas ocidentais foram realizados em amostras de mucosa intestinal de pacientes com diabetes tipo 2 nos períodos pré- e pós-operatório. RESULTADOS: Todos os resultados foram consistentes e indicaram expressão basal e secreção de peptídeos glucagon-1 (GLP-1) e peptídeos YY (PYY3-36) incretinas por células L. Uma maior densidade de células foi demonstrada nas porções mais distais do intestino delgado. Não foi encontrada diferença significativa entre os níveis de expressão GLP-1 e PYY3-36 nos períodos pré-operatório e pós-operatório, provavelmente devido ao estado de jejum prolongado durante o qual as amostras foram coletadas CONCLUSÃO: O maior número de células L em atividade implica melhor sinalização de peptídeo, resposta e funcionamento do sistema neuroendócrino.

Small intestinal l cell density in patients with severe obesity after roux-en-y gastric bypass / Avaliação da densidade das células l no intestino delgado em obesos graves após gastroplastia em y-de-roux

ABSTRACT BACKGROUND: Enteroendocrine L cells can be found in the entire gastrointestinal tract and their incretins act on glycemic control and metabolic homeostasis. Patients with severe obesity and type 2 diabetes mellitus may have lower density of L cells in the proximal intestine. AIMS: This study aimed to analyze the density of L cells in the segments of the small intestine in the late postoperative of Roux-en-Y gastric bypass in diabetic patients with standardization of 60 cm in both loops, alimentary and biliopancreatic. METHODS: Immunohistochemistry analysis assays were made from intestinal biopsies in three segments: gastrointestinal anastomosis (GIA= Point A), enteroenteral anastomosis (EEA= Point B= 60 cm distal to the GIA) and 60 cm distal to the enteroenteral anastomosis (Point C). RESULTS: A higher density of L cells immunostaining the glucagon-1 peptide was observed in the distal portion (Point C) when compared to the more proximal portions (Points A and B). CONCLUSIONS: The concentration of L cells is higher 60 cm distal to enteroenteral anastomosis when comparing to proximal segments and may explain the difference in intestinal lumen sensitization and enterohormonal response after Roux-en-Y gastric bypass.

RESUMO RACIONAL: As células L enteroendócrinas podem ser encontradas na extensão de todo trato gastrointestinal e suas incretinas atuam no controle glicêmico e da homeostase metabólica. Estudos mostram que pacientes obesos graves com diabetes mellitus tipo 2 apresentam má sinalização entero-hormonal e baixa resposta da secreção do peptídeo glucagon-1, que poderia ser explicado por uma densidade menor de células L ou uma distribuição mais distal ao longo do intestino delgado. OBJETIVOS: Analisar a diferença da densidade de células L nos segmentos do intestino delgado de pacientes obesos graves submetidos à gastroplastia em Y de Roux, em período pós-operatório tardio, com padronização de alça alimentar e biliopancreática com extensão de 60 cm em ambas. MÉTODOS: Ensaios de análises de imuno-histoquímica foram feitos a partir de biopsias intestinais obtidas em três segmentos: junto à anastomose gastrointestinal (AGI= Ponto A), junto à anastomose entero-enteral (AEE= Ponto B= 60 cm distal à AGI) e 60 cm distalmente à anastomose entero-enteral (Ponto C). Os resultados foram obtidos por meio de imunomarcação do peptídeo glucagon-1 secretado pelas células L. RESULTADOS: Foi observada maior densidade de células L na porção mais distal do intestino delgado (Ponto C) quando comparada às porções mais proximais (Ponto A e B). CONCLUSÕES: Em pacientes no pós-operatório de gastroplastia em Y de Roux, identificou-se concentração maior de células L já na porção a 60 cm distalmente a entero-entero anastomose quando comparada aos segmentos proximais, o que pode explicar diferenças na sensibilização no lúmen intestinal e na resposta entero-hormonal.

Possible Common Origin of B Chromosomes in Neotropical Fish (Siluriformes, Auchenipteridae) Reinforced by Repetitive DNA Mapping

Abstract The aim of this paper was to present the second case of B chromosomes in Auchenipteridae (Trachelyopterus sp.), and to test the hypothesis that the B chromosomes of this species and Parauchenipterus galeatus might have a common origin, since these two species have phylogenetic proximity. Both species have 58 chromosomes in the A complement, heterochromatin preferentially located at terminal region of the most of chromosomes, simple Ag-NORs located at the short arm of a subtelocentric pair, which was confirmed by hybridization with 18S rDNA, two submetacentric pairs carrying 5S rDNA sites, and presence of B chromosomes. The B chromosomes of the two species are small, metacentric, and almost totally heterochromatic, with variation of number intra and interindividual. In addition, for the first time in fish, the telomeric sequence [TTAGGG]n was dispersed along the B chromosomes (both species). The [GATA]n microsatellite were scattered in all chromosomes of the A complement and absent in the B chromosomes, in both species. These aspects confirm the phylogenetic proximity between the genus Parauchenipterus and Trachelyopterus, and they suggest the hypothesis that the B chromosomes of the two species might have common origin, previous to the diversification of these genera.

Does evolutionary biology help the understanding of metabolic surgery? a focused review / A biologia evolutiva ajuda na compreensão da cirurgia metabólica? uma revisão com foco

ABSTRACT Introduction: The wide net of physiological issues involved in metabolic surgery is extremely complex. Nonetheless, compared anatomy and phisiology can provide good clues of how digestive tracts are shaped for more or less caloric food, for more or less fiber, for abundance and for scarcity. Objective: To review data from Compared Anatomy and Physiology, and in the Evolutionary Sciences that could help in the better comprehension of the metabolic surgery. Method: A focused review of the literature selecting information from these three fields of knowledge in databases: Cochrane Library, Medline and SciELO, articles and book chapters in English and Portuguese, between 1955 and 2019, using the headings "GIP, GLP-1, PYY, type 2 diabetes, vertebrates digestive system, hominid evolution, obesity, bariatric surgery ". Results: The digestive tract of superior animals shows highly specialized organs to digest and absorb specific diets. In spite of the wide variations of digestive systems, some general rules are observed. The proximal part of the digestive tract, facing the scarcity of sugars, is basically dedicated to generate sugar from different substrates (gluconeogenesis). Basic proximal gut tasks are to proportionally input free sugars, insulin, other fuels and to generate anabolic elements to the blood, some of them obesogenic. To limit the ingestion by satiety, by gastric emptying diminution and to limit the excessive elevation of major fuels (sugar and fat) in the blood are mostly the metabolict asks of the distal gut. A rapid and profound change in human diet composition added large amounts of high glycemic index foods. They seem to have caused an enhancement in the endocrine and metabolic activities of the proximal gut and a reduction in these activities of the distal gut. The most efficient models of metabolic surgery indeed make adjustments in this proximal/distal balance in the gut metabolic activities. Conclusion: Metabolic surgery works basically by making adjustments to the proximal and distal gut metabolic activities that resemble the action of natural selection in the development the digestive systems of superior animals.

RESUMO Introdução: A rede de questões fisiológicas envolvidas na cirurgia metabólica é muito complexa. No entanto, a anatomia e fisiologia comparadas podem fornecer boas pistas sobre como o trato digestivo é moldado para alimentos mais ou menos calóricos, para mais ou menos fibras, para abundância e escassez. Objetivo: Selecionar e analisar dados de Ciências Evolucionárias e Anatomia e Fisiologia Comparadas que ajudam na compreensão da cirurgia metabólica. Método: Revisão focada da literatura, selecionando informações desses três campos de conhecimento em bancos de dados da Cochrane Library, Medline e SciELO, artigos e capítulos de livros em inglês e português, entre 1950 e 2019, usando como descritores "GIP, GLP-1, PYY, type 2 diabetes, vertebrates digestive system, hominid evolution, obesity, bariatric surgery". Resultado: O trato digestivo de animais superiores mostra órgãos altamente especializados para digerir e absorver dietas específicas..A parte proximal, diante da escassez de açúcares, é basicamente dedicada à geração de açúcar a partir de diferentes substratos (gliconeogênese). As tarefas básicas do intestino proximal consistem em fornecer proporcionalmente açúcares livres, insulina e outros combustíveis e gerar elementos anabólicos no sangue, alguns deles obesogênicos. Limitar a ingestão pela saciedade, por diminuir o esvaziamento gástrico e limitar a elevação excessiva dos principais combustíveis (açúcar e gordura) no sangue são principalmente as tarefas metabólicas do intestino distal. Mudança rápida e profunda na composição da dieta humana causa elevação nas atividades endócrinas e metabólicas do intestino proximal e redução no intestino distal. Os modelos mais eficientes de cirurgia metabólica fazem ajustes nesse equilíbrio proximal-distal das atividades metabólicas intestinais. Conclusão: A cirurgia metabólica funciona basicamente fazendo ajustes nas atividades metabólicas do intestino proximal e distal que se assemelham à ação da seleção natural no desenvolvimento dos sistemas digestivos de animais superiores.

Swim training and the genetic expression of adipokines in monosodium glutamate-treated obese rats

Objective The aim of this study was to evaluate the genetic expression of adipokines in the adipocytes of monosodium glutamate (MSG)-treated obese rats submitted to physical activity.Materials and methods Obesity was induced by neonatal MSG administration. Exercised rats (MSG and control) were subjected to swim training for 30 min for 10 weeks, whereas their respective controls remained sedentary. Total RNA was obtained from sections of the mesenteric adipose tissue of the rats. mRNA levels of adiponectin (Adipoq), tumor necrosis factor alpha (Tnf), peroxisome proliferator-activated receptor alpha (Ppara), and peroxisome proliferator-activated receptor gamma (Pparg) adipokines were quantified by quantitative Real-Time Polymerase Chain Reaction (qRT-PCR).Results In the exercise-trained control group, the expression of Adipoq increased compared to the sedentary control, which was not observed in the MSG-obese rats. Increased levels of Tnf in MSG-obese rats were not reversed by the swim training. The expression of Ppara was higher in sedentary MSG-obese rats compared to the sedentary control. Swimming increased this adipokine expression in the exercise-trained control rats compared to the sedentary ones. mRNA levels of Pparg were higher in the sedentary MSG-rats compared to the sedentary control; however, the exercise did not influenced its expression in the groups analyzed.Conclusions In conclusion, regular physical activity was not capable to correct the expression of proinflammatory adipokines in MSG-obese rat adipocytes.

Hipertensão arterial de difícil controle e o polimorfismo A1166C do gene AT1 / Difficult-to-treat hypertension and AT1 A1166C gene polymorphism

Fundamentos: Polimorfismos presentes em genes que codificam proteínas do sistema renina-angiotensina aldosterona (SRAA) estão associados com o quadro de hipertensão arterial sistêmica (HAS) em algumas populações. Estudos demonstram a relação entre o polimorfismo A1166C no gene do receptor tipo 1 da angiotensina II (AT1) com a HAS, mas os dados ainda são controversos. Objetivo: Analisar a presença deste polimorfismo em pacientes portadores de HAS resistente da região dos Campos Gerais (PR), Brasil. Materiais e Métodos: Grupos de pacientes com hipertensão de fácil (G1) (n = 34) e difícil controle medicamentoso (G2) (n = 39) foram analisados quanto ao polimorfismo mencionado, utilizando-se a técnica de Polymerase Chain Reaction­ Restriction Fragment Lenght Polymorphism (PCR-RFLP). Os pacientes foram categorizados em três genótipos: AA, AC e CC. As frequências alélicas e genotípicas foram calculadas para cada grupo e os dados confrontados com as características metabólicas e antropométricas dos indivíduos. Resultados: não houve diferença entre os grupos quanto a sexo e idade. O índice de massa corporal (IMC), pressão arterial sistólica (PAS), diastólica (PAD) e número de anti-hipertensivos utilizados foram maiores no G2. Asfrequências alélicas e genotípicas mostraram-se semelhantes entre os grupos (p > 0,05). Conclusão: Nesta população, este polimorfismo não está associado ao fácil ou difícil controle da pressão arterial (PA). Possivelmente, outros fatores devem estar influenciando a HAS nestes pacientes

Background: Polymorphisms in genes encoding proteins of the renin-angiotensin-aldosterone system (RAAS) are associated with systemic arterial hypertension (SAH) in some populations. Some reports demonstrated the relationship between the angiotensin II type 1 receptor (AT1) A1166C gene polymorphism with SAH, but the data are still controversial. Objective: To analyze the presence of this polymorphism in patients porting difficult-to-treat SAH from Campos Gerais region (PR), Brazil. Materials and Methods: Groups of patients porting hypertension easy (G1) (n = 34) and difficult-to-treat using drugs (G2) (n = 39) were analyzed according to the polymorphism mentioned, using the Polymerase Chain Reaction­ Restriction Fragment Lenght Polymorphism (PCR-RFLP) technique. The patients were categorized into three genotypes: AA, AC and CC. The allele and genotype frequencies were calculated and the results were compared with metabolic and anthropometric characteristics of the patients. Results: There was no difference between groups regarding gender and age. The body mass index (BMI), systolic and diastolic blood pressures and the number of antihypertensive drugs were higher in G2. The allele and genotype frequencies were similar between the groups (p > 0.05). Conclusions: In this population, the polymorphism analyzed is not associated with easy or difficult-to-treat SAH. Possibly, other factors are influencing the hypertension in these patients

Relação do polimorfismo C825T do gene GNB3 e hipertensão arterial sistêmica de difícil controle / Relationship between C825T polymorphism of the GNB3 gene and dificult-to-treat hypertension

Fundamentos: O polimorfismo C825T do gene GNB3 está associado à hipertensão arterial sistêmica (HAS) em algumas populações já analisadas, porém alguns estudos se mostram controversos no que se refere a esta relação. Objetivo: Avaliar a relação do polimorfismo C825T do gene GNB3 com a HAS de difícil controle medicamentoso em hipertensos de Campos Gerais, PR - Brasil. Métodos: Em relação ao polimorfismo C825T de GNB3, foram determinados os genótipos de 60 hipertensos, os quais foram estratificados em dois grupos (fácil e difícil controle medicamentoso), por meio da técnica de PCR-RFLP (Polymerase Chain Reaction - Restriction Fragment Lenght Polymorphism). Foram avaliadas as frequências alélicas e genotípicas, utilizando-se o teste do qui-quadrado de Pearson, com correção de Yates e odds ratio (OR). Resultados: Não houve diferenças entre os grupos, quando comparadas as frequências alélicas e genotípicas, indicando que a população está em equilíbrio. A probabilidade de o paciente possuir o polimorfismo e a HAS de difícil controle foi 53,5 % (OR=1,15; IC95 % = 0,41-3,26), analisando-se os genótipos. Já a análise dos alelos, separadamente, mostrou uma associação de 55,4 % (OR=1,24; IC95 % = 0,59-2,57). Conclusão: Nesta população não foi encontrada relação entre o polimorfismo C825T do gene GNB3 e a HAS de difícil controle, indicando que outros fatores estão influenciando a manifestação dessa doença nestes pacientes.

Background: C825T polymorphism of the GNB3 gene is associated with systemic arterial hypertension (SAH) in some studied populations, although certain studies are controversial in terms of this relationship. Objective: To evaluate the relationship between C825T polymorphism of the GNB3 gene and difficult-to-treat SAH among hypertensive patients in Campos Gerais, Paraná State, Brazil. Methods: With regard to C825T polymorphism of the GNB3 gene, the genotypes were defined for sixty hypertensive patients divided in 2 groups (easy and difficult-to-treat with drugs), using the Polymerase Chain Reaction - Restriction Fragment Length Polymorphism (PCR-RFLP) technique. The allele and genotype frequencies were assessed through the Pearson chi-square test, with Yates correction and odds ratio (OR). Results: There were no differences between the groups when comparing the allele and genotype frequencies, indicating that the population is in equilibrium. The probability that a patient has polymorphism with difficult-to-treat SAH reached 53.5% (OR=1.15, 95%CI = 0.41-3.26), analyzing the genotypes. A separate allele analysis showed an association of 55.4% (OR=1.24, 95%CI = 0.59-2.57). Conclusion: No relationship was found in this population between C825T polymorphism of the GNB3 gene and difficult-to-treat SAH, indicating that other factors are influencing the appearance of this disease among these patients.

Karyotype variability in neotropical catfishes of the family pimelodidae (Teleostei: Siluriformes)

Dados cariotípicos são apresentados para quatro espécies da família Pimelodidae. Todas apresentaram o mesmo número diploide, 2n = 56 cromossomos, com diferenças nas fórmulas cariotípicas. As espécies aqui analisadas mostraram pouca quantidade de heterocromatina localizada preferencialmente na região centromérica e telomérica de alguns cromossosmos do complemento cariotípico. As regiões organizadoras de nucléolo (Ag-RONs) e a localização dos genes ribossomais pela hibridização in situ fluorescente (FISH), com sondas 18S e 5S, evidenciaram somente um par cromossômico marcado portador de genes ribossomais, à exceção de Pimelodus britskii que apresentou NORs múltiplas e localização sintênica das sondas 18S e 5S. Eventos não-Robertsonianos, como inversão pericêntrica e duplicação das NORs são requeridos para explicar a diversificação cariotípica em Pseudoplatystoma do rio Paraguai (MS), Pimelodus do rio Iguaçu (PR), Sorubim do rio Paraguai (MS) e Steindachneridion do rio Paraíba do Sul (SP). Os dados obtidos para a macroestrutura cariotípica destas espécies corrobora um padrão conservado observado na família Pimelodidae. Por outro lado, evidências de variações interespecíficas pelos marcadores de citogenética molecular empregados possibilitam inferências citotaxonômicas e diferenciação das espécies aqui analisadas.

Karyotypic data are presented for four species of fish belonging to the Pimelodidae family. These species show a conserved diploid number, 2n = 56 chromosomes, with different karyotypic formulae. The analyzed species showed little amount of heterochromatin located preferentially in the centromeric and telomeric regions of some chromosomes. The nucleolus organizer regions activity (Ag-NORs) and the chromosomal location of ribosomal genes by fluorescent in situ hybridization (FISH), with 18S and 5S probes, showing only one chromosome pair marked bearer of ribosomal genes, the only exception was Pimelodus britskii that presented multiple NORs and syntenic location of the 18S and 5S probes. Non-Robertsonian events, as pericentric inversion and NORs duplication are requested to explain the karyotype diversification in Pseudoplatystoma from the rio Paraguay (MS), Pimelodus from the rio Iguaçu (PR), Sorubim from the rio Paraguay (MS) and Steindachneridion from the rio Paraíba do Sul (SP). The obtained data for the karyotype macrostructure of these species corroborates a conserved pattern observed in Pimelodidae. On the other hand, interspecific variations detected by molecular cytogenetics markers made possible cytotaxonomic inferences and differentiation of the species here analyzed.

Metabolic effects of an entero-omentectomy in mildly obese type 2 diabetes mellitus patients after three years

BACKGROUND: Various digestive tract procedures effectively improve metabolic syndrome, especially the control of type 2 diabetes mellitus. Very good metabolic results have been shown with vertical gastrectomy and entero-omentectomy; however, the metabolic effects of an isolated entero-omentectomy have not been previously studied. METHODS: Nine patients with type 2 diabetes mellitus and a body mass index ranging from 29 to 34.8 kg/m² underwent an entero-omentectomy procedure that consisted of an enterectomy of the middle jejunum and exeresis of the major part of the omentum performed through a mini-laparotomy. Glucagon-like peptide-1 and peptide YY were measured preoperatively and three months following the operation. Fasting and postprandial variations in glycemia, insulinemia, triglyceridemia, hemoglobin A1c, and body mass index were determined in the preoperative period and 3, 18 and, 36 months after the operation. RESULTS: All patients significantly improved the control of their type 2 diabetes mellitus. Postprandial secretion of peptide YY and Glucagon-like peptide-1 were enhanced, whereas hemoglobin A1c, fasting and postprandial glucose, insulin, and triglyceride levels were significantly reduced. Mean body mass index was reduced from 31.1 to 27.3 kg/m². No major surgical or nutritional complications occurred. CONCLUSIONS: Entero-omentectomy is easy and safe to perform. A simple reduction in jejunal extension and visceral fat causes important improvements in the metabolic profile.

Preliminary qualitative analysis on mtDNA in Astyanax fasciatus populations Cuvier, 1819 (Teleostei; Characidae) indicate population distinctiveness

A preliminary qualitative analysis of genetic variability status in Astyanax fasciatus (Cuvier, 1819) from upper Tibagi River headwaters and Vila Velha State Park (VVSP) was carried out by enzymatic digestion (RFLP) of D-Loop region from mtDNA. The results showed that Tibagi and VVSP populations were genetically different.

Uma análise qualitativa da variabilidade genética em Astyanax fasciatus (Cuvier, 1819) do alto Rio Tibagi e Parque Estadual de Vila Velha (PEVV) foi conduzida por digestão enzimática (RFLP) da região D-Loop do mtDNA. Os resultados evidenciaram que essas populações são geneticamente diferentes.

Cytogenetic analysis of Astylus antis (Perty, 1830) (Coleoptera, Melyridae): Karyotype, heterochromatin and location of ribosomal genes

Cytogenetic analysis of Astylus antis using mitotic and meiotic cells was performed to characterize the haploid and diploid numbers, sex determination system, chromosome morphology, constitutive heterochromatin distribution pattern and chromosomes carrying nucleolus organizer regions (NORs). Analysis of spermatogonial metaphase cells revealed the diploid number 2n = 18, with mostly metacentric chromosomes. Metaphase I cells exhibited 2n = 8II+Xyp and a parachute configuration of the sex chromosomes. Spermatogonial metaphase cells submitted to C-banding showed the presence of small dots of constitutive heterochromatin in the centromeric regions of nearly all the autosomes and on the short arm of the X chromosome (Xp), as well as an additional band on one of the arms of pair 1. Mitotic cells submitted to double staining with base-specific fluorochromes (DAPI-CMA3) revealed no regions rich in A+T or G+C sequences. Analysis of spermatogonial mitotic cells after sequential Giemsa/AgNO3 staining did not reveal any specific mark on the chromosomes. Meiotic metaphase I cells stained with silver nitrate revealed a strong impregnation associated to the sex chromosomes, and in situ hybridization with an 18S rDNA probe showed ribosomal cistrons in an autosomal bivalent.

Comparative cytogenetics among populations of Astyanax altiparanae (Characiformes, Characidae, Incertae sedis)

Cytogenetic data are presented for Astyanax altiparanae populations from three Brazilian hydrographic systems. The chromosomal data obtained in A. altiparanae support the hypothesis of diploid number conservation. However, small differences in the karyotype formula and number of nucleolar organizer regions were observed in these populations. The apparent karyotypical similarity among the studied populations strongly suggests a close relationship among them with some chromosomal divergences due to gene flow restriction.

Chromosomal studies of five species of the marine fishes from the Paranaguá Bay and the karyotypic diversity in the marine teleostei of the Brazilian coast

In this study, five species of marine fishes from the Paranaguá Bay in the Brazilian coast were evaluated. Eucinostomus argenteus and Diapterus rhombeus (Gerreidae) presented 48 chromosomes, all of which more acrocentric (FN = 48); Strongylura timucu and S. marina (Belonidae) also presented 48 chromosomes, but with a higher karyotypic complexity than the Gerreidae, 10M+2SM+36A (FN = 60) and 4M+44A (FN = 52), respectively. The fifth species, Mugil curema (Mugilidae), different than the others, presented only 28 chromosomes 20M+4ST+4A (FN = 48). The species presented diversity in the karyotypic macro-structure, which should be relevant for the cytotaxonomy and the evolution of this group of the vertebrate.

Nas últimas décadas tem ocorrido no Brasil um incremento de estudos cariotípicos em peixes marinhos. Atualmente são conhecidos os cariótipos de 118 espécies, distribuídas em 43 famílias e 80 gêneros. Foram estudadas cinco espécies de peixes marinhos do complexo estuarino da Baía de Paranaguá na costa brasileira. Eucinostomus argenteus e Diapterus rhombeus (Gerreidae), apresentaram 48 cromossomos todos acrocêntricos (NF = 48); Strongylura timucu e S. marina (Belonidae) apresentaram 48 cromossomos, porém com complexidade cariotípica maior do que apresentada pelos gerreídeos, 10M+2SM+36A (NF = 60) e 4M+44A (NF = 52), respectivamente. A quinta espécie, Mugil curema (Mugilidae), ao contrário das outras quatro espécies aqui analisadas, apresentou apenas 28 cromossomos 20M+4ST+4A (NF = 48). Apesar da tendência em se verificar um cariótipo constituído por 48 cromossomos em teleósteos marinhos, as espécies aqui analisadas apresentam uma diversidade para a macroestrutura cariotípica a ser considerada para a citotaxonomia e evolução desse grupo de vertebrados.

Comparative cytogenetics among species of the Astyanax scabripinnis complex: evolutionary and biogeographical inferences

Karyotype data are presented for distinct species of the genus Astyanax from four rivers belonging to three different hydrographic basins of the State of Paraná, Brazil (Verde River - Tibagi basin, Açungui River - Ribeira basin, and Santo Antônio and Jaguariaíva Rivers - Jaguariaíva basin). Three karyotypic forms were identified, here denominated karyotype A (2n = 50 chromosomes, with 8m+18sm+10st+14a, and thirteen 18S rDNA sites); karyotype B (2n = 50 chromosomes, with 8m+18sm+10st+1f4a, and four 18S rDNA sites); and karyotype C (2n = 48 chromosomes, with 10m+16sm+10st+12a, and eight 18S rDNA sites). The pattern of constitutive heterochromatin was similar among the three karyotypic forms, with few differences. The 5S rDNA corresponds to a synapomorphic character regarding its number and chromosomal localization. The karyotypic form A occurs in the distribution center of the type locality of A. paranae, in the proximities of the town of Castro (Tibagi basin), and may have reached the headwaters of the Ribeira River by the breakdown of geographical barriers. The karyotypic forms B and C are sympatric and syntopic, occurring solely in the Jaguariaíva River basin. Our hypothesis is that the karyotypic form A corresponds to the species A. paranae and forms B and C correspond to other species of the A. scabripinnis complex.

Population analysis of a chromosome polymorphism in Astyanax (Teleostei, Characiformes) species endemic to the Iguaçu River

Chromosomal analyses were performed in the fish Astyanax sp.D collected from three different points: two streams from the right bank and one from the left bank of the Upper Iguaçu River, Paraná State, Brazil. The individuals from all localities possess 2n = 50 chromosomes and a FN = 84 (4m+24sm+6st+16a). The C-banding pattern was similar in all populations. However, within each population, an interindividual variation concerning the number and localization of heterochromatic bands was observed. Some of these variations were quantified in each population, and the results indicate that the samples were not different when studying the variable frequencies. Considering that Astyanax sp.D is typical in the headwaters of the Iguaçu River, these results were not expected. The data indicate that gene flow is occurring and that the Iguaçu River is not an ecological barrier among the Astyanax sp. D populations.

Cytotaxonomic and evolutionary considerations about karyotipic data of fishes from the Iguaçu River Basin in South of Brazil

The cytogenetic data available in the literature about the ichthyofauna of the Iguaçu River basin were analyzed in this review. The ichthyofauna was characterized by the high level of endemism and by the low diversity of species. Twenty-four of the eighty-one species were already karyotyped; six Characiformes, fourteen Siluriformes and four Perciformes. The chromosomal data showed the taxonomic and systematic complexity of the groups. Hypothesis related to the evolution of some Characiformes and Siluriformes groups from the Iguaçu River are proposed, as well as the utilization of karyotypic data for cytotaxonomy.

Nesta revisão são analisados os dados citogenéticos disponíveis na literatura relativos à ictiofauna da bacia do Rio Iguaçu, a qual é caracterizada pelo alto grau de endemismo e pela baixa diversidade de espécies. Das oitenta e uma espécies conhecidas, vinte e quatro já foram cariotipadas sendo 6 Characiformes, 14 Siluriformes e 4 Perciformes. Os dados cromossômicos evidenciam a complexidade taxonômica e sistemática dos grupos. São propostas hipóteses relacionadas à evolução de alguns grupos de Characiformes e Siluriformes do Rio Iguaçu, assim como o aproveitamento de dados cariotípicos para a citotaxonomia.

Astylus variegatus (Coleoptera, Melyridae): Cytogenetic study of a population exposed to agrochemical products

In this work we describe the cytogenetic analyses performed in specimens of Astylus variegatus (Germar, 1824) collected in two localities: one area of natural vegetation and one of agricultural crops, where agrochemical products were used. Astylus variegatus had karyotypes with 2n(male) = 16+Xy p and 2n (female) = 16+XXp, with exclusively metacentric chromosomes. Pachytene spermatocytes showed synapsed autosomal bivalents and non-associated sex chromosomes. In diplotene, the autosomal bivalents exhibited one or two terminal chiasmata and the Xy p had a typical parachute configuration. In meiotic cells of some specimens, an extra chromosome, interpreted as a B chromosome, was observed. C-banding showed constitutive heterochromatin in the pericentromeric region of all chromosomes, with the exception of the y p. Silver nitrate staining revealed one nucleolus organizer region (NOR) on the terminal region of the short arm of the second autosome pair. Silver staining of meiotic cells confirmed the NOR pattern detected in mitotic cells and revealed an argentophilous material on the Xy p. A cytogenetic comparison between the two populations of A. variegatus showed a statistically significant divergence (chi2 = 117.10; df = 1) in the number of aneuploid cells and a higher frequency of B chromosome in the population exposed to agrochemicals.

Cytogenetics and biogeography: considerations about the natural origin of Hoplias malabaricus ( Characiformes, Erythrinidae ) on the Iguaçu river

Hoplias malabaricus (traíra) é uma espécie de peixe com ampla distribuição pela região Neotropical e alta diversidade cariotípica interpopulacional (citótipos), que podem corresponder a um complexo de espécies. Apesar da sua ampla distribuição pelas bacias hidrográficas da América do Sul, alguns autores têm questionado sua origem natural no rio Iguaçu, uma importante bacia hidrográfica brasileira que é caracterizada pela presença de várias espécies de peixes endêmicas. Assim, nós temos analisado o cariótipo de H. malabaricus de diferentes locais de coleta neste rio por métodos convencionais e bandamentos cromossômicos. Nossos resultados, em adição a dados prévios a respeito da distribuição geográfica dos citótipos contribuem para um melhor entendimento da origem de H. malabaricus no rio Iguaçu, reforçando a proposta que esta é uma espécie de peixe natural desta bacia hidrográfica.

Cytogenetic analysis and chromosomal characteristics of the polymorphic 18S rDNA in the fish Prochilodus lineatus (Characiformes, Prochilodontidae)

We used differential staining techniques (BSG, GTG, AgNO3, DAPI and CMA3 banding) and fluorescent in situ hybridization (FISH) with 5S and 18S probes to investigated the karyotypic and cytogenetic chracteristics of Prochilodus lineatus specimens from a population in Vila Velha state park (Parque Estadual de Vila Velha, Ponta Grossa, Paraná state, southern Brazil). The specimens studied showed the same karyotype as that found in other P. lineatus populations, i.e. 2n = 54 biarmed chromosomes (40m + 14 sm) and c-positive heterochromatin preferentially located pericentromerically in all chromosomes. The presence of partial or totally heterochromatic supernumerary chromosomes with numeric intra-individual variation was confirmed in the analyzed population. The nucleolar organizing regions (NORs) were interstitially situated on the long arm of chromosome pair 4 directly beneath the centromere. The differential banding techniques and FISH revealed NOR size polymorphism due to structural events such as breaks and duplication of the larger rDNA site cluster. We also observed syntenic localization of the 5S ribosomal genes in the distal segment of the 45S cluster.