Inferências carioevolutivas sobre grupos crípticos de peixes marinhos e estuarinos

Cytogenetic studies have been revealing a great diversity not detected, until then, in several families of fishes. Many of these groups, especially those that exhibit great diversity, like Perciformes and Siluriformes, possess species with difficult morphologic characterization, called cryptic species, commonly detected through karyotypic analyses, which reveals outstanding interespecific variations with relationship to the number and its chromosomal structures. Thus, the present work intends to contribute for the cytogenetic knowledge of marine and brackish fish species, because they peculiar life habits and by lack of cytogenetic data of your genetic aspects. Therefore, cytogenetic studies were developed in a species of Apogonidae (Perciformes), two species of sea catfishes of the family Ariidae (Siluriformes) and brackish fish Paurachenipterus galeatus (Siluriformes, Auchenipteridae), through C banding, Ag-NOR, use of base-specific flourochromes (DAPI and CMA3), as well as FISH (Fluorescent in situ hybridization) using ribosomal DNA probes 5S and 18S. The present results contribute to a better understanding of the processes of differentiation patterns and chromosome evolution in these groups. The use of other approaches (the morphology and molecular tools) will allow a larger understanding of the genetic and biological diversity of the Brazilian ichthyofauna.

Padrões cariotípicos em tetraodontiformes (Osteichthypes) :redução genômica e mecanismos de diversificação

The Tetraodontiformes order is composed for about 400 species of fish, distributed in ten families, with circuntropical distribution. The morphologic diversity of each family reflects in, part, the different levels of specialization. This group represents an ancestry after-Perciformes and constitutes the last branch of the diffusion of the Teleósteos, occupying a position of prominence. The phylogenetics relationships of the Tetraodontiformes exist diverse works examining and, in all, these families are recognized as groups brothers, being Diodontidae next to Tetraodontidae and Balistidae next to Monacanthidae. Although it possesss a representative number of species, the works involving of the families Balistidae and Monacanthidae are few exemplary, especially species of oceanic islands. In this work cytogenetic studies in five species had been analyzed Cantherhines macrocerus, Cantherhines pullus (Monacanthidae), Melichthys niger (Balistidae), Sphoeroides testudíneus (Tetraodontidae) and Chilomycterus antennatus (Diodontidae); through conventional coloration, Ag-NORs and C banding. Ahead of the different karyological trends of evolution presented by the Tetraodontiformes, the present work also searched to verify the relation existence enters the total size of the chromosomes with the amount of DNA in these groups of Tetraodontiformes. For such, they had been correlated the total size of the chromosomes of these species, with values of content of available DNA in literature. The cytogenetics analyses for the species C.macrocerusJ C.pullus (Monacanthidae) and M.niger (Balistidae), had disclosed 40 chromosomes, all acrocentrics. All possess only one pair of NORs and pericentromeric heterochromatin. For S.testudíneus the found dyploid number was equal 2n=46, with NF=78 (16m+18sm+8st+4a), while that for C.antennatus it possesss 2n=50, with NF=76 (4m+22st+24a). Both species possess simple NORs and pericentromeric heterochromatin blocks. In M.niger, the presence of positive marking (heterochromatin and NOR) in the secondary constriction in the second chromosomic pair suggesting the occurrence of a rearrangement, possibly a fusing involving these homologous ones, indicating that these events had been important for the establishment of the karyological history of this group. A maintenance of the chromosomic constancy found in the populations of C.macrocerus (Monacanthidae) and S.testudineus (Tetraodontidae) perhaps if must for the aiding of the gene flow through oceanic chains. These data contrast with the differentiated kinds of chromosomes of C.antennatus between the Northeast coast and Southeastern, suggesting that the ecological standards of each species, added to the conditions of the marine environment, can be responsible for the karyological delineation of each species. The found characteristics for the species C.macrocerus, C.pullus, M.niger, S.testudineus and C.antennatus add it the available data for other species of Tetraodontiformes. From the data gotten in the present study, it can be inferred that the DNA content possesss direct relation with the total length of the chromosomes

Investigação das alterações citogenéticas em pacientes pediátricos com leucemia linfóide aguda do Rio Grande do Norte

Leukemia is a heterogeneous group of hematologic malignancies that result from partial or total transformation of the blast cells. The Acute Lymphoblastic Leukemia (ALL) is the most common malignancy in childhood, especially in male, Caucasian children younger than 14 years. Several criteria are adopted to classify ALL, including the cell morphology, cytochemistry, immunophenotyping and cytogenetic analysis. Cytogenetic studies allow a more detailed analysis to detect chromosomal abnormalities of leukemic cells. These modifications will determine the diagnosis, classification, stage characterization, remission assessment and prognosis. In this study were evaluated 30 patients, aged from four months to seventeen years, of both sexes and various ethnicities. The age distribution showed that 67% of patients had between one and ten years (with mean age of XX years old), the most prevalent ethnic was Caucasian (50%) and 57% were males. According to immunophenotype, 93% of patients had B-cells progenitor ALL and 7% early lineage T. Considering the total studied population, the most frequent medical findings were lymphadenopathy (37%), hepatomegaly (77%) and splenomegaly (70%), where one patient could present more than one of these medical findings. Regarding the CBC, the majority of patients had hemoglobin below 10 g / dl (73%), leukocyte count less than 10.000/μL (60%) and platelet count below 150.000/μL (83%). Chromosomal abnormalities were observed in 64% of all patients, where hyperdiploidy was the most common numerical change (67%), followed by hypodiploid (33%). All these data are in agreement with the literature. Moreover, complexes structural and/or number changes not yet described in literature were observed, which indicated poor prognosis. Finally, we concluded that this study demonstrated the importance of cytogenetic study in the diagnosis and identification of prognostic factors in pediatric patients with ALL in Rio Grande do Norte. The results obtained in this study are extremely useful and emphasizes that surveys of this nature must be conducted more frequently in our state

Padrões cromossômicos e mapeamento de genes ribossomais 18S e 5S em peixes pelágicos Atlânticos

Cytogenetic studies in fish have been contributed significantly to a better understanding of the marine biodiversity, presenting information related to characterization, evolution and conservation of species e fisheries stocks. Among the marine species which cytogenetic data are less well known pelagic forms are detached, that despite the economic importance and conservation efforts have been suffering great pressure from the artisanal and industrial fisheries. The present work characterized cytogenetically six species of large pelagic fish in the Atlantic, belonging to the Order Perciformes, among them, four species of Scombridae, Thunnus albacares, T. obesus, Scomberomorus brasiliensis and Acanthocybium solandri and two Coryphaenidae, Coryphaena equiselis and C. hippurus using Classical cytogenetic methods as conventional staining, C-banding and Ag-NORs and molecular through staining fluorochromes AT and GC-specific and mapping of ribosomal multigene families, 18S and 5S. The identification of phylogenetic patterns and cytotaxonomic markers between the species and the presence of sex chromosomes in at least one species of Coryphaenidae, are particularly useful in the formulating of phylogenetic hypotheses, as well as comparisons between groups and populations

Fecal androgen levels in common marmoset (Callithrix jacchus) males living in captive family groups

In captive common marmoset groups, the reproductive inhibition observed in subordinate female seems to be a result of olfactory, visual and behavioral cues from the dominant female. However, few studies have examined the relationship among adult males living in the same social group. These studies have shown that reproductive failure among peer males seems to be based on hormonal and behavioral mechanisms. New insights on sexual strategies in primates have been shown using fecal steroids, but so far no information is available for common marmoset males. In the present study, we evaluated the influence of light-dark cycle, age and reproductive condition on the profile of fecal androgens in males living in the same family group. Feces were collected from six fathers and six sons for androgen determination during the light phase of the 24-h cycle for eight days randomly distributed over a 4-week period. Androgen levels were determined by enzyme immunoassay technique. Adult sons showed higher androgen levels (166.97 ± 22.95 ng/g) than fathers (80.69 ± 44.38 ng/g) and juveniles (49.06 ± 23.15 ng/g; P < 0.05). No diurnal variation (P > 0.05) in fecal androgen profile was observed in adults or juveniles. No indication of androgen-mediated social competition between fathers and adult sons was demonstrable. These results provide basic information on fecal androgen profile useful to investigate the socioendocrinology of free-ranging common marmoset males and verify that, in contrast to daughters, the reproductive suppression of sons is not based on physiological inhibition of their gonads

Processos carioevolutivos na ordem tetraodontiformes: uma visão através de suas diferentes linhagens

Given the great diversity of fishes, the Order Tetraodontiformes stands to show genetic and morphological characteristics enough singular. The fishes of this order have a compact DNA which favors molecular studies, as well as comparisons with more basal species. Model of genome evolution, there are still many gaps in knowledge about their chromosomal patterns and how evolutionary rearrangements influence the marked variation in DNA content of this order. In view of this, we present cytogenetic analyzes of the species Acanthostracion quadricornis (Ostraciidae), A. polygonius (Ostraciidae) Melichthys niger (Balistidae) Cantherhines macrocerus (Monacanthidae) and C. pullus (Monacanthidae), Lagocephalus laevigatus, Colomesus psittacus and Canthigaster figueiredoi (Tetraodontidae), to contribute with cytogenetic data for this group. The analysis was performed by C-banding, Ag-RONs, coloring with base-specific fluorochromes DAPI-CMA3, restriction enzymes AluI, EcoRI, TaqI, PstI and HinfI and in situ hybridization with probes for ribosomal DNA 18S and 5S. The heterochromatic ultrastructure of A. quadricornis and A. polygonius revealed a outstanding heterochromatin content, which may indicate that the accumulation or loss of extensive heterochromatin content could be responsible for large variations in genomic content displayed in different Tetraodontiformes families. The species Cantherhines macrocerus, C. pullus (Monacanthidae) and Melichthys niger (Balistidae) shows a huge karyotypic similarity both numerically and structural. L. laevigatus showed similar cytogenetic features (2n = 44 and single RONs) to the species of the genus Takifugu, which reinforces the idea of their phylogenetic relationships. C. psittacus presented the highest diploid number described for the family (2n = 56) and large amount of HC, features that related with its sister family Diodontidae. Cytogenetic analysis in C. figueiredoi revealed heterochromatic polymorphisms, RONs multiple and Bs chromosomes. These events are rare in marine fishes, and are possibly associated with the strong restructuring and genomic reduction that this family has been suffered. These features, plus the morphological and molecular data suggests that these species share the same ancestral branch, with a possible monophyletic origin. In this study, new contributions to the knowledge of evolutionary patterns facing by Tetraodontiformes are provided and discussed under cytotaxonomyc, genomic and evolutionary perspectives.

Contribuição à citogenética de testudines e análise de assimetria flutuante em Eretmochelys imbricata, Cheloniidae

This work has contributed to knowledge of the order Testudines from cytogenetic and morphological point of view. With regard to the aspects proposed cytogenetic characterization of the species Mesoclemmys tuberculata (n = 5), endemic to the Caatinga biomes, through conventional techniques of cytogenetics and molecular levels. This species presented 2n = 58, NF = 64, the first submetacentric pair, the second metacentric and third subtelocentric, and the other microchromosome telocentric. This species showed a nucleolar bearing pair, coincident with the 18S ribosomal rDNA and that proved to be heterochromatic. Small heterochromatic blocks were also found in the centromeres of the largest chromosomes, as well as terminal regions in most other chromosomes of the complement, that were GC +. Telomeric sequences showed variable patterns of signal intensity, with some repeats more intense in microchromosomes and subtly in the larger ones. When compared with other species of the genus, the G-banding patterns showed a marked similarity between them. The first karyotypic description of the species will aid in future studies and the understanding of evolutionary aspects of this family. From the morphological point of view, we carried out studies of fluctuating asymmetry in sea turtle Eretmochelys imbricata, using methods of benchmarking between hatchlings and adults and their implications for natural selection. Data were collected at two different times: first during the spawning female and the second during the outbreak and birth of the nest. The analyzed characteristics consisted of measurements of length and width of front and rear flippers (CANT, LANT, CPOS and LPOS) also collected data on the number of hull plates, side plates (NPL), the surrounding plates (NPCIRC), and plastron; plates power plants (NPP), inframarginais plates (NPIM). With the values of asymmetry we calculated the value of strict heritability for these traits, the calculation was based on only one parent. A nonparametric analysis Mann-Whitneywas performed to compare the groups (females X hatchlings, newborn hatchlings X dead hatchlings). Adult females showed no bilateral fluctuating asymmetry (FA = 0) on the number plates of the hull and plastron, while offspring, living and dead, showed a greater level of variation in these meristic parameters. In the analysis of females x hatchlings we found a significant difference between the levels of asymmetry in hoof plates (p=0.006) an the width of hindlimbs (p=0.001). Levels of FA suggest an accurate indicator as to the viability or maintenance of the individual to the reproductive phase. The coefficient of heritability (h2) of FA , obtained from the regression analysis, showed that both have low and not statistically significant values(p> 0.1). In the case of exclusion of the effective role of genetics in the generation of FA, reproductive strategies based on high number of subsidiaries products, such as those observed in E. imbricata seems to implicate the production of individuals with high level of developmental instability

Levantamento cariotípico em espécies de peixes marinhos costeiros de fundo arenoso (Osteichthypes, Perciformes)

Cytogenetics analyses in fish are important because they compose a private group among the vertebrates, occupying a central position in the animal evolution. The Perciforms Order, dominant in the marine and freshwater environment, it constitutes a model potentially useful in the genetic evaluation of populations, as well as in the understanding of its evolutionary processes. In spite of this, cytogenetics studies in this great group is scarce, above all for the inhabitants of sandy bottom and pelagics habits. The present work proposed to contribute for the cytogenetic characterization of nine species of fish marine of sandy bottom of the coast of Rio Grande do Norte (Brazil), identifying the evolutionary patterns related to the karyotype in these species and the existence of filogenetics affinities between them and other Perciformes. The animals were collected in the beaches of the Redinha, Ponta Negra and Búzios (Coast of Rio Grande do Norte) and in Saint Peter and Saint Paul Archipelago. Later on they were submitted to the cytogenetics technical that consist of mitotic estimulation, obtaining of mitotics chromosomes, proceeded by techniques of conventional coloration (Giemsa) and chromosomic bands (Ag-RONs and C band). Diploid number and fundamental number equal to 48 were observed in most of the species: Menticirrhus americanus, Ophioscion punctatissimus, Pareques acuminatus (Sciaenidae); Chloroscombrus chrysurus (Carangidae); Echeneis sp. 2 (Echeneidae); Archosargus probatocephalus (Sparidae) and Orthopristis ruber (Haemulidae). Trachinotus goodei (NF=52) (Carangidae) and Echeneis sp. 1 (Echeneidae) (NF=54) presented variation in NF, staying constant a diploid number equal to 48. RONs was situated in pericentromeric position in whole the scianids, and in the species Echeneis sp. 2 (22° pair), O. ruber and A. probatocephalus (1° pair), coinciding with great heterocromatics blocks in M. americanus (1° pair), P. acuminatus (2° pairl) and O. ruber (1° pair). RONs was also located in the telomeric area of the short arm of the 5° and 11° acrocentrics pairs in T. goodei, 4° and 19° pairs of C. chrysurus, 1° pair (sm) of Echeneis sp. 1. The C band detected centromeric blocks in most of the chromosomes of the species of Sciaenidae, Carangidae and Echeneidae, with great blocks in A. probatocephalus (4° pair). Heterocromatic blocks in telomeric areas in submetacentrics of Echeneis sp. 1, and pericentromerics in M. americanus (1° and 8° pairs), O. punctatissimus (1° pair) and P. acuminatus (2° pair) were also observed. It is noticed a marked conservatism cromossomic in the species of the family Scianidae and Haemulidae in what says respect to the number of acrocentrics chromosomes and the location of RONs. Even so it is outstanding the presence of heterocromatinization events during the karyotypic evolution of this family. Already in the families Sparidae and Carangidae, the obtained results reaffirm examples of small variations structural resultants of inversion and translocation Robertsonian, as important mechanisms of diversification karyotipical, as well as a pattern numerical evolutionary conserved, also observed in representatives of Echeneidae of Atlantic in relation to Pacific. The presence of RONs multiple, observed in the species T. goodei and C. chrysurus seems to represent a character derived in the family Carangidae. The results for the species O. ruber and A. probatocephalus suggest the presence of possible geographical or climatic barriers among populations of NE of Brazil in relationship the one of the SE

Mapeamento cromossômico de DNAs repetitivos com fins biotecnológicos em peixes marinhos e interesse comercial - Rachycentridae e Lutjanidae

The Rachycentron canadum species, commonly known as beijupirá or cobia is the only representative of Rachycentridae family which has been increasingly used in marine fish farming, in intensive cultivation. As advantageous features it has easy adaptation, prolific behavior, early growth in captivity and high commercial value. Additionally, specie of Lutjanidae family (Lutjanus synagris, Lutjanus jocu, Lutjanus analis, Lutjanus alexandrei and Ocyurus chrysurus) represents an important fisheries resource in all areas of its occurrence. In Brazil, the commercial exploitation of Lutjanidae which begun in the 60's and 80's, already has showed a decline in catch volumes. This fact suggests that the snappers must have a conservative management. Despite the economic potential, little is known about the genetic and cytogenetic characteristics of these species, especially with respect to repetitive DNA analysis, which represents the major part of the eukaryotes genome, playing important evolutionary roles in the fish genome. Cytogenetic data is increasingly being used in population studies and biotechnological purposes in fishes. The cytogenetical analyzes were performed using classical methods such as Giemsa staining, C-banding and Ag-NORs, fluorochromes base-specific staining (DAPI and MM) and physical mapping of repetitive sequences among which, telomeric sequences, transposons (Tol2), retrotransposons (Rex1 and Rex3), repetitive DNA (microsatellites and Cot-1) and transcriptionally active regions of the 18S and 5S ribosomal genes and histone (H3 and H2BA) by in situ hybridization with fluorescent probes (FISH). The chromosomal patterns obtained contributed to the organization of repetitive sequences in the genome of the species, as well as karyotypical differentiation. Unusual patterns of histone sequences expansion depict the first occurrence in marine fishes. The obtained data provided subsides to the genetic knowledge of the important fisheries resource represented by the species here analyzed, seeking the marine pisciculture improvement.

Fecal androgen levels in common marmoset (Callithrix jacchus) males living in captive family groups

In captive common marmoset groups, the reproductive inhibition observed in subordinate female seems to be a result of olfactory, visual and behavioral cues from the dominant female. However, few studies have examined the relationship among adult males living in the same social group. These studies have shown that reproductive failure among peer males seems to be based on hormonal and behavioral mechanisms. New insights on sexual strategies in primates have been shown using fecal steroids, but so far no information is available for common marmoset males. In the present study, we evaluated the influence of light-dark cycle, age and reproductive condition on the profile of fecal androgens in males living in the same family group. Feces were collected from six fathers and six sons for androgen determination during the light phase of the 24-h cycle for eight days randomly distributed over a 4-week period. Androgen levels were determined by enzyme immunoassay technique. Adult sons showed higher androgen levels (166.97 ± 22.95 ng/g) than fathers (80.69 ± 44.38 ng/g) and juveniles (49.06 ± 23.15 ng/g; P < 0.05). No diurnal variation (P > 0.05) in fecal androgen profile was observed in adults or juveniles. No indication of androgen-mediated social competition between fathers and adult sons was demonstrable. These results provide basic information on fecal androgen profile useful to investigate the socioendocrinology of free-ranging common marmoset males and verify that, in contrast to daughters, the reproductive suppression of sons is not based on physiological inhibition of their gonads