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1.
Neotrop. ichthyol ; 18(2): e190093, 2020. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1135375

RESUMO

Several organisms match their skin color to the prevalent background color, granting crypsis against predators. The rate at which body color changes occur varies among organisms as a result of physiological constraints and adaptation to variation in contrasts between objects and the environmental background. Faster darkening of body color is favored in environments that show higher amounts of contrast between common objects and the prevailing background. Soil types in Amazon forest streams (igarapés) create distinct environments with respect to the amount of contrast, a result of the amount of sand and clay, which offers different contrasts against dead leaves. Here, we investigated differences in the rates of color change among populations of the sailfin tetra (Crenuchus spilurus) that represent lineages that live in regions of different soil types. Populations inserted into blackwaters (sandy soil) showed higher rates of color darkening in response to exposure to a dark environment composed by dead leaves. We propose that natural selection stemming from predation can favor faster color change rate in environments where there is higher variability of contrasts between leaf litter and soil, which is common in most blackwater streams.(AU)


Diversos organismos combinam sua coloração corporal com a cor de fundo predominante no ambiente, conferindo cripticidade contra predadores. A taxa na qual as mudanças de coloração corpórea ocorrem varia entre os organismos como resultado de restrições fisiológicas e adaptação à variação de contrastes entre objetos e o ambiente. O escurecimento mais rápido da cor do corpo é favorecido em ambientes que mostram maiores quantidades de contraste entre objetos comuns e o fundo predominante. Tipos de solo em igarapés da floresta amazônica criam ambientes distintos em relação à quantidade de contraste, resultado da quantidade de areia e argila, que oferece diferentes contrastes contra folhiço submerso. Nós investigamos as diferenças nas taxas de mudança de cor entre populações do tetra-colibri Crenuchus spilurus que representam linhagens que vivem em regiões de diferentes tipos de solo. Populações inseridas em águas pretas (solo arenoso) apresentaram maiores taxas de escurecimento da cor em resposta à exposição ao ambiente escuro de folhiço submerso. Nós propomos que a seleção natural decorrente da predação pode favorecer uma taxa de mudança de cor mais rápida em ambientes onde há maior variabilidade de contrastes entre o folhiço submerso e o solo, o que é comum na maioria dos igarapés de águas pretas.(AU)


Assuntos
Animais , Seleção Genética , Solo , Adaptação , Characidae/crescimento & desenvolvimento , Characidae/fisiologia
2.
Braz. j. biol ; 79(4): 639-645, Nov. 2019. tab, graf
Artigo em Inglês | LILACS | ID: biblio-1001491

RESUMO

Abstract In order to evaluate aspects of reproductive biology of the "pequira" ( Bryconamericus stramineus) in the elevator of the Funil Dam - MG, fish capture was carried out from November 2008 to January 2009 and 317 individuals were collected. The mean standard length (SL) of the population was 4.96 cm and mean weight 1.80 g. The females had SL of 5.0 cm, while males had a SL of 4.6 cm. A sex ratio of 2.20: 1 (females: male) was observed. Our results show that 73% of the individuals analyzed were considered adults. The species presented low fecundity, mean of 470.9 oocytes per female and a mean diameter of 221.08 μm, with an increase in oocyte diameter over the evaluation period. The length of the first gonadal maturation was estimated at 5.0 cm. The results obtained in this work suggest that the reproductive cycle of the species occurs in the analyzed period. Although this species does not have migratory reproductive habits, the presence of adults in the reproductive stage was observed in the transposition area, which suggests a search for new environments for spawning.


Resumo Com o objetivo de avaliar aspectos da biologia reprodutiva da pequira Bryconamericus stramineus no elevador da represa do Funil - MG foram realizadas capturas entre os meses de novembro de 2008 a janeiro de 2009, sendo coletados 317 indivíduos. O comprimento padrão (CP) médio da população foi de 4,96 cm e peso médio de 1,80 g. As fêmeas apresentaram CP de 5,0 cm, enquanto que os machos obtiveram um CP de 4,6 cm. Foi observada proporção sexual de 2,20:1(fêmeas:macho). Dos indivíduos analisados, 73% foram considerados adultos. A espécie apresentou baixa fecundidade, com média de 470,9 ovócitos por fêmea e diâmetro médio de 221,08 μm, ocorrendo aumento no diâmetro de ovócitos com o decorrer do tempo no período avaliado. O comprimento de primeira maturação gonadal foi estimado em 5,0 cm. Os resultados obtidos neste trabalho sugerem que o ciclo reprodutivo da espécie ocorre no período analisado. Embora esta espécie não tenha hábitos reprodutivos migratórios, a presença de adultos no estágio reprodutivo foi observada na área de transposição, o que sugere a busca de novos ambientes para a reprodução.


Assuntos
Animais , Feminino , Reprodução/fisiologia , Characidae/crescimento & desenvolvimento , Characidae/fisiologia , Estações do Ano , Razão de Masculinidade , Brasil , Rios , Fertilidade
3.
Arq. bras. med. vet. zootec. (Online) ; 71(5): 1595-1600, set.-out. 2019. tab
Artigo em Português | LILACS, VETINDEX | ID: biblio-1038643

RESUMO

O objetivo deste trabalho foi determinar a digestibilidade do farelo de palmiste (Elaeis guineensis) para o tambaqui (Colossoma macropomum), em duas classes de peso: 1 (210 alevinos de 4,45±1,18g) e 2 (54 juvenis de 115,91±4,01g). Os coeficientes de digestibilidade aparente (CDA) da matéria seca, proteína bruta e energia bruta do farelo de palmiste foram avaliados pela metodologia de substituição da dieta referência, utilizando-se 0,1% de óxido crômico como indicador externo. Os dados foram analisados pelo teste t de Student, a 5% de probabilidade. Os CDAs da matéria seca, proteína bruta e energia bruta do ingrediente foram iguais (P>0,05) nas classes de peso avaliadas. Os CDAs observados nas classes 1 e 2, respectivamente, foram: matéria seca (17,52% e 20,75%), proteína bruta (62,83% e 63,75%) e energia bruta (14,16% e 22,43%). A capacidade do tambaqui para digerir os nutrientes do farelo de palmiste não foi influenciada pelo peso corporal, e o aproveitamento satisfatório da proteína (63,29%) faz desse ingrediente uma potencial fonte alternativa de proteína em dietas para a espécie.(AU)


The objective of this work was to determine the digestibility of palm kernel meal (Elaeis guineensis) in tambaqui (Colossoma macropomum), in two weight classes: 1 (210 fingerlings of 4.45±1.18g) and 2 (54 juveniles of 115.91±4.01g). The apparent digestibility coefficients (ADC) of dry matter, crude protein and crude energy of the palm kernel meal were evaluated by the substitution of the reference diet methodology, using 0.1% chromic oxide as an external indicator. Data were analyzed by Student's t-test at 5% probability. The dry matter, crude protein and crude energy ADCs of the ingredient were the same (P> 0.05) in the weight classes evaluated. The ADCs observed in classes 1 and 2, respectively, were: dry matter (17.52% and 20.75%), crude protein (62.83% and 63.75%) and crude energy (14.16% and 22.43%). The ability of tambaqui to digest the nutrients of palm kernel meal was not influenced by body weight, and satisfactory protein utilization (63.29%) makes this ingredient a potential alternative source of protein in diets for the species.(AU)


Assuntos
Elaeis guineensis , Aquicultura/métodos , Characidae/crescimento & desenvolvimento , Resíduos de Alimentos , Ração Animal/análise
4.
Nat Commun ; 10(1): 4231, 2019 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-31530801

RESUMO

Acoustic communication allows the exchange of information within specific contexts and during specific behaviors. The blind, cave-adapted and the sighted, river-dwelling morphs of the species Astyanax mexicanus have evolved in markedly different environments. During their evolution in darkness, cavefish underwent a series of morphological, physiological and behavioral changes, allowing the study of adaptation to drastic environmental change. Here we discover that Astyanax is a sonic species, in the laboratory and in the wild, with sound production depending on the social contexts and the type of morph. We characterize one sound, the "Sharp Click", as a visually-triggered sound produced by dominant surface fish during agonistic behaviors and as a chemosensory-, food odor-triggered sound produced by cavefish during foraging. Sharp Clicks also elicit different reactions in the two morphs in play-back experiments. Our results demonstrate that acoustic communication does exist and has evolved in cavefish, accompanying the evolution of its behaviors.


Assuntos
Evolução Biológica , Characidae/fisiologia , Acústica , Adaptação Fisiológica , Comunicação Animal , Animais , Cavernas , Characidae/crescimento & desenvolvimento , Feminino , Masculino
5.
Genome Biol Evol ; 11(9): 2563-2573, 2019 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-31418011

RESUMO

Organisms living in the subterranean biome evolve extreme characteristics including vision loss and sensory expansion. Despite prior work linking certain genes to Mendelian traits, the genetic basis for complex cave-associated traits remains unknown. Moreover, it is unclear if certain forms of genetic variation (e.g., indels, copy number variants) are more common in regressive evolution. Progress in this area has been limited by a lack of suitable natural model systems and genomic resources. In recent years, the Mexican tetra, Astyanax mexicanus, has advanced as a model for cave biology and regressive evolution. Here, we present the results of a genome-wide screen for in-frame indels using alignments of RNA-sequencing reads to the draft cavefish genome. Mutations were discovered in three genes associated with blood physiology (mlf1, plg, and wdr1), two genes associated with growth factor signaling (ghrb, rnf126), one gene linked to collagen defects (mia3), and one gene which may have a global epigenetic impact on gene expression (mki67). With one exception, polymorphisms were shared between Pachón and Tinaja cavefish lineages, and different from the surface-dwelling lineage. We confirmed the presence of mutations using direct Sanger sequencing and discovered remarkably similar developmental expression in both morphs despite substantial coding sequence alterations. Further, three mutated genes mapped near previously established quantitative trait loci associated with jaw size, condition factor, lens size, and neuromast variation. This work reveals previously unappreciated traits evolving in this species under environmental pressures (e.g., blood physiology) and provides insight to genetic changes underlying convergence of organisms evolving in complete darkness.


Assuntos
Characidae/genética , Proteínas de Peixes/genética , Mutação INDEL , Animais , Evolução Biológica , Cavernas , Characidae/classificação , Characidae/crescimento & desenvolvimento , Characidae/fisiologia , Perfilação da Expressão Gênica , Genoma , Locos de Características Quantitativas , Análise de Sequência de RNA
7.
Artigo em Inglês | MEDLINE | ID: mdl-30290221

RESUMO

In vertebrates, the essential fatty acids (FA) that satisfy the dietary requirements for a given species depend upon its desaturation and elongation capabilities to convert the C18 polyunsaturated fatty acids (PUFA), namely linoleic acid (LA, 18:2n-6) and α-linolenic acid (ALA, 18:3n-3), into the biologically active long-chain (C20-24) polyunsaturated fatty acids (LC-PUFA), including arachidonic acid (ARA, 20:4n-6), eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3). Recent studies have established that tambaqui (Colossoma macropomum), an important aquaculture-produced species in Brazil, is a herbivorous fish that can fulfil its essential FA requirements with dietary provision C18 PUFA LA and ALA, although the molecular mechanisms underpinning such ability remained unclear. The present study aimed at cloning and functionally characterizing genes encoding key desaturase and elongase enzymes, namely fads2, elovl5 and elovl2, involved in the LC-PUFA biosynthetic pathways in tambaqui. First, a fads2-like desaturase was isolated from tambaqui. When expressed in yeast, the tambaqui Fads2 showed Δ6, Δ5 and Δ8 desaturase capacities within the same enzyme, enabling all desaturation reactions required for ARA, EPA and DHA biosynthesis. Moreover, tambaqui possesses two elongases that are bona fide orthologs of elovl5 and elovl2. Their functional characterization confirmed that they can operate towards a variety of PUFA substrates with chain lengths ranging from 18 to 22 carbons. Overall our results provide compelling evidence that demonstrates that all the desaturase and elongase activities required to convert LA and ALA into ARA, EPA and DHA are present in tambaqui within the three genes studied herein, i.e. fads2, elovl5 and elovl2.


Assuntos
Ácido Araquidônico/metabolismo , Characidae/fisiologia , Ácidos Docosa-Hexaenoicos/metabolismo , Ácido Eicosapentaenoico/metabolismo , Fígado/enzimologia , Acetiltransferases/química , Acetiltransferases/genética , Acetiltransferases/metabolismo , Sequência de Aminoácidos , Animais , Aquicultura , Brasil , Characidae/crescimento & desenvolvimento , Ácidos Graxos Dessaturases/química , Ácidos Graxos Dessaturases/genética , Ácidos Graxos Dessaturases/metabolismo , Elongases de Ácidos Graxos , Proteínas de Peixes/química , Proteínas de Peixes/genética , Proteínas de Peixes/metabolismo , Isoenzimas/química , Isoenzimas/genética , Isoenzimas/metabolismo , Fígado/crescimento & desenvolvimento , Fígado/metabolismo , Necessidades Nutricionais , Organismos Geneticamente Modificados , Filogenia , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Rios , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Especificidade por Substrato
8.
Zebrafish ; 16(2): 182-188, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30562152

RESUMO

Astyanax is an abundant fish genus in South America. Some species of this group are characterized by the presence of B chromosomes and absence of morphologically differentiated sex chromosomes. In this study, we used quantitative real-time polymerase chain reaction to characterize mRNA expression of dmrt1 in Astyanax scabripinnis gonads. Maturing gonads of males with the B chromosome overexpressed dmrt1. Our findings suggest that B chromosomes may have an adaptive role in A. scabripinnis sex determination and maintenance.


Assuntos
Characidae/crescimento & desenvolvimento , Characidae/genética , Proteínas de Peixes/genética , Expressão Gênica/genética , Gônadas/crescimento & desenvolvimento , Processos de Determinação Sexual/genética , Fatores de Transcrição/genética , Animais , Feminino , Proteínas de Peixes/metabolismo , Gônadas/embriologia , Gônadas/metabolismo , Masculino , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Fatores de Transcrição/metabolismo
9.
Chemosphere ; 220: 266-274, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30590293

RESUMO

The toxicity of metals, including aluminum (Al), can be potentiated by temperature and acid pH, a concern in view of the current global warming scenario. The aim of this study was to evaluate the bioconcentration of Al in the testes and semen of Astyanax altiparanae and the potential of this metal, at different environmental temperatures and acid pH, to cause cytotoxicity and genotocixity in erythrocytes and spermatozoa. A. altiparanae males were divided into nine experimental groups: at each of three different water temperatures (20, 25 and 30 °C), the fish were exposed to a neutral pH, an acid pH and acidic water containing Al (0.5 mg.L-1). The fish were subjected to subacute, semi-static exposure and sampled at 24 and 96 h. After each exposure period the comet assay (blood and semen) and micronucleus test (blood) were performed. Bioconcentration of Al was evaluated in the testes and semen. Exposure time and temperature influenced the Al bioconcentration pattern in the testes. Al concentration in the semen was higher in fish exposed at 20 and 25 °C (24 h). The DNA fragmentation score for the semen and blood was higher in fish exposed to Al at 20 (24 h) and 30 °C (96 h). The frequency of nuclear abnormalities in erythrocytes was higher in the group exposed to Al at 30 °C (96 h). It was concluded that Al bioconcentrates in the testes and semen of A. altiparanae at different temperatures and is potentially cytotoxic and genotoxic to erythrocytes and spermatozoa in this species.


Assuntos
Alumínio/toxicidade , Characidae/crescimento & desenvolvimento , Dano ao DNA/efeitos dos fármacos , Espermatozoides/efeitos dos fármacos , Testículo/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Characidae/metabolismo , Ensaio Cometa , Água Doce , Concentração de Íons de Hidrogênio , Masculino , Testes para Micronúcleos , Temperatura
10.
Braz J Biol ; 79(4): 639-645, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30379203

RESUMO

In order to evaluate aspects of reproductive biology of the "pequira" ( Bryconamericus stramineus) in the elevator of the Funil Dam - MG, fish capture was carried out from November 2008 to January 2009 and 317 individuals were collected. The mean standard length (SL) of the population was 4.96 cm and mean weight 1.80 g. The females had SL of 5.0 cm, while males had a SL of 4.6 cm. A sex ratio of 2.20: 1 (females: male) was observed. Our results show that 73% of the individuals analyzed were considered adults. The species presented low fecundity, mean of 470.9 oocytes per female and a mean diameter of 221.08 µm, with an increase in oocyte diameter over the evaluation period. The length of the first gonadal maturation was estimated at 5.0 cm. The results obtained in this work suggest that the reproductive cycle of the species occurs in the analyzed period. Although this species does not have migratory reproductive habits, the presence of adults in the reproductive stage was observed in the transposition area, which suggests a search for new environments for spawning.


Assuntos
Characidae , Reprodução/fisiologia , Animais , Brasil , Characidae/crescimento & desenvolvimento , Characidae/fisiologia , Feminino , Fertilidade , Masculino , Rios , Estações do Ano , Razão de Masculinidade
11.
Neotrop. ichthyol ; 17(1): e170123, 2019. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-990196

RESUMO

Moenkhausia bonita occurs in numerous additional localities from the Bermejo, Paraná, Paraguay, and Uruguay river basins. Given that this finding greatly expands the distributional range of M. bonita, we carried out an intraspecific comparison, using multivariate methods for 18 morphometric and eight meristic characters taken from a comprehensive sample of 536 specimens. All localities were distributed in four major geographic groups as follows: Bermejo, Paraná, Paraguay, and Uruguay. Results of the morphometric comparisons showed significant differences among the studied groups except between the Paraguay and Uruguay groups. Statistical differences in meristic values were found for most between-group comparisons, especially in those resulting from discriminant canonical analyses (DCA). Specimens from the Bermejo basin were the most distinct group in most morphological comparisons. However, the overall subtle differences found in body morphology likely reflect intraspecific variation within M. bonita and seem to be mainly influenced by spatial and environmental features of drainages. As M. bonita was previously identified as M. intermedia in the río de La Plata basin, distributional comments on the latter species in that basin are provided.(AU)


Moenkhausia bonita es registrada en numerosas localidades adicionales de las cuencas de los ríos Bermejo, Paraná, Paraguay, y Uruguay. Dado que estos hallazgos expanden ampliamente el rango distribucional de M. bonita, nosotros llevamos a cabo una comparación intraespecífica, usando métodos multivariados para 18 características morfométricas y 8 merísticas que fueron tomados en una muestra exhaustiva de 536 especímenes. Todas las localidades fueron repartidas en cuatro grupos principales como sigue: Bermejo, Paraná, Paraguay y Uruguay. Los resultados de las comparaciones morfométricas mostraron diferencias significativas a través de los grupos bajo estudio, excepto entre los grupos Paraguay y Uruguay. Diferencias estadísticas fueron encontrados en la mayoría de las comparaciones entre los grupos, especialmente en aquellas obtenidas de los análisis discriminantes canónicos (ADC). Los especímenes de la cuenca del Bermejo fueron encontrados como el grupo más divergente en la mayoría de las comparaciones morfológicas. No obstante, estas leves diferencias encontradas en la morfología del cuerpo son consideradas dentro de la variación intraespecífica de M. bonita y parecen estar influidas por características ambientales y espaciales de los drenajes. Dado que M. bonita fue previamente identificada como M. intermedia en la cuenca del río de La Plata, comentarios distribucionales sobre esta última especie en esta cuenca son presentados.(AU)


Assuntos
Animais , Characidae/crescimento & desenvolvimento , Geomorfologia
12.
Environ Pollut ; 243(Pt A): 723-733, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30228063

RESUMO

The increase of production and consumption of copper oxide nanostructures in several areas contributes to their release into aquatic ecosystems. Toxic effects of copper oxide nanoparticles (CuO NPs), in particular, on tropical aquatic organisms are still unknown, representing a risk for biota. In this study, the effects of rod-shaped CuO NPs on the Neotropical species Ceriodaphnia silvestrii and Hyphessobrycon eques were investigated. We also compared the toxicity of CuO NPs and CuCl2 on these species to investigate the contribution of particles and cupper ions to the CuO NPs toxicity. Considering the low copper ions release from CuO NPs (<1%), our results revealed that the toxicity of CuO NPs to C. silvestrii and H. eques was mainly induced by the NPs. The 48 h EC50 for C. silvestrii was 12.6 ±â€¯0.7 µg Cu L-1 and for H. eques the 96 h LC50 was 211.4 ±â€¯57.5 µg Cu L-1 of CuO NPs. There was significant decrease in reproduction, feeding inhibition and increase in reactive oxidative species (ROS) generation in C. silvestrii exposed to CuO NPs. In fish H. eques, sublethal exposure to CuO NPs caused an increase in ROS generation in gill cells and an increase in cells number that were in early apoptotic and necrotic stages. Our results showed that CuO NPs caused toxic effects to C. silvestrii and H. eques and ROS play an important role in the toxicity pathway observed. Data also indicated that C. silvestrii was among the most sensitive species for CuO NPs. Based on predicted environmental concentration in water bodies, CuO NPs pose potential ecological risks for C. silvestrii and H. eques and other tropical freshwater organisms.


Assuntos
Characidae/crescimento & desenvolvimento , Cladóceros/crescimento & desenvolvimento , Cobre/toxicidade , Nanopartículas Metálicas/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Organismos Aquáticos/efeitos dos fármacos , Organismos Aquáticos/crescimento & desenvolvimento , Cladóceros/efeitos dos fármacos , Brânquias/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo
13.
Nat Ecol Evol ; 2(7): 1155-1160, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29807993

RESUMO

Coding and non-coding mutations in DNA contribute significantly to phenotypic variability during evolution. However, less is known about the role of epigenetics in this process. Although previous studies have identified eye development genes associated with the loss-of-eyes phenotype in the Pachón blind cave morph of the Mexican tetra Astyanax mexicanus, no inactivating mutations have been found in any of these genes. Here, we show that excess DNA methylation-based epigenetic silencing promotes eye degeneration in blind cave A. mexicanus. By performing parallel analyses in A. mexicanus cave and surface morphs, and in the zebrafish Danio rerio, we have discovered that DNA methylation mediates eye-specific gene repression and globally regulates early eye development. The most significantly hypermethylated and downregulated genes in the cave morph are also linked to human eye disorders, suggesting that the function of these genes is conserved across vertebrates. Our results show that changes in DNA methylation-based gene repression can serve as an important molecular mechanism generating phenotypic diversity during development and evolution.


Assuntos
Characidae/genética , Metilação de DNA , Epigênese Genética/genética , Olho/crescimento & desenvolvimento , Inativação Gênica , Animais , Evolução Biológica , Cavernas , Characidae/crescimento & desenvolvimento , Fenótipo
14.
Sci Rep ; 8(1): 7015, 2018 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-29725043

RESUMO

The precise mechanisms underlying cranial bone development, evolution and patterning remain incompletely characterised. This poses a challenge to understanding the etiologies of craniofacial malformations evolving in nature. Capitalising on natural variation, "evolutionary model systems" provide unique opportunities to identify underlying causes of aberrant phenotypes as a complement to studies in traditional systems. Mexican blind cavefish are a prime evolutionary model for cranial disorders since they frequently exhibit extreme alterations to the skull and lateral asymmetries. These aberrations occur in stark contrast to the normal cranial architectures of closely related surface-dwelling fish, providing a powerful comparative paradigm for understanding cranial bone formation. Using a longitudinal and in vivo analytical approach, we discovered two unusual ossification processes in cavefish that underlie the development of 'fragmented' and asymmetric cranial bones. The first mechanism involves the sporadic appearance of independent bony elements that fail to fuse together later in development. The second mechanism involves the "carving" of channels in the mature bone, a novel form of post-ossification remodeling. In the extreme cave environment, these novel mechanisms may have evolved to augment sensory input, and may indirectly result in a trade-off between sensory expansion and cranial bone development.


Assuntos
Characidae/crescimento & desenvolvimento , Ossos Faciais/crescimento & desenvolvimento , Osteogênese , Animais , Estudos Longitudinais
15.
Artigo em Inglês | MEDLINE | ID: mdl-29783005

RESUMO

In the present study, metal (As, Cd, Cu, Fe, Mn, Pb and Zn) accumulation and expression of genes involved in metal metabolism (metallothioneins, ATP7A and CTR1) were evaluated in gills and muscle of the fish Hyphessobrycon luetkenii living in the João Dias creek, a site historically (~1870-1996) contaminated with a metal mixture associated with copper mining (Minas do Camaquã, southern Brazil). Fish were collected in a metal impacted site of the João Dias creek and kept in a cage at this site (PP fish) or translocated to a non-metal impacted reach of this creek (PC fish). Gill metal concentrations and metallothionein gene expression were lower in PC fish than in PP fish at any experimental time (24, 48 and 72 h). In muscle, no significant changes were observed. These findings indicate that metal accumulated in gills of wild fish chronically exposed to the metal mixture are more easily excreted than those accumulated in the muscle. In this case, expression of gene encoding for metallothionein is shown to play a key role in the regulation of metal accumulation in gills of H. luetkenii living in an area historically contaminated with a metal mixture associated with copper mining.


Assuntos
Animais Selvagens/fisiologia , Characidae/fisiologia , ATPases Transportadoras de Cobre/metabolismo , Cobre/toxicidade , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Metalotioneína/metabolismo , Poluentes Químicos da Água/toxicidade , Animais , Animais Selvagens/crescimento & desenvolvimento , Brasil , Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Characidae/crescimento & desenvolvimento , Cobre/metabolismo , ATPases Transportadoras de Cobre/genética , Exposição Ambiental/efeitos adversos , Feminino , Proteínas de Peixes/genética , Proteínas de Peixes/metabolismo , Brânquias/efeitos dos fármacos , Brânquias/crescimento & desenvolvimento , Brânquias/metabolismo , Masculino , Metalotioneína/genética , Metais Pesados/metabolismo , Metais Pesados/toxicidade , Mineração , Desenvolvimento Muscular/efeitos dos fármacos , Músculos/efeitos dos fármacos , Músculos/metabolismo , Especificidade de Órgãos , Rios , Toxicocinética , Poluentes Químicos da Água/metabolismo
16.
J Fish Biol ; 92(5): 1560-1573, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29633274

RESUMO

The larval ultrastructure of Brycon gouldingi related to swimming and feeding from hatching to total yolk absorption is described from scanning electron micrographs. Newly hatched larvae (time zero) had no mouth opening, undefined optic vesicles, an olfactory plate visible as a shallow depression, rudimentary gill arches, neural groove, embryonic fin and a primary neuromast in the dorsal region of the head. At the time of yolk absorption, 55 h post hatching, the larvae presented an optic vesicle comprising an optic cup and crystalline lens; a mouth with tongue, tapered teeth and taste buds; a ciliated olfactory cavity; branched gill arches; filled neural groove signalling central nervous system development; caudal, pectoral, dorsal and anal fins; and neuromasts distributed throughout the head and body. These characters are related to prey capture and swimming ability, key aspects of survival during the larval stage. The results of this study provide important information for exploitation and aquaculture of B. gouldingi.


Assuntos
Characidae/anatomia & histologia , Larva/ultraestrutura , Natação/fisiologia , Animais , Aquicultura , Characidae/crescimento & desenvolvimento , Characidae/fisiologia , Comportamento Alimentar , Feminino , Larva/crescimento & desenvolvimento , Larva/fisiologia , Masculino , Microscopia Eletrônica de Varredura
17.
J Vis Exp ; (142)2018 12 28.
Artigo em Inglês | MEDLINE | ID: mdl-30638199

RESUMO

River and cave-adapted populations of Astyanax mexicanus show differences in morphology, physiology, and behavior. Research focused on comparing adult forms has revealed the genetic basis of some of these differences. Less is known about how the populations differ at post-larval stages (at the onset of feeding). Such studies may provide insight into how cavefish survive through adulthood in their natural environment. Methods for comparing post-larval development in the laboratory require standardized aquaculture and feeding regimes. Here we describe how to raise fish on a diet of nutrient-rich rotifers in non-recirculating water for up to two-weeks post fertilization. We demonstrate how to collect post-larval fish from this nursery system and perform whole-mount immunostaining. Immunostaining is an attractive alternative to transgene expression analysis for investigating development and gene function in A. mexicanus. The nursery method can also be used as a standard protocol for establishing density-matched populations for growth into adults.


Assuntos
Characidae/metabolismo , Imuno-Histoquímica/métodos , Animais , Characidae/crescimento & desenvolvimento , Larva , Fenótipo
18.
Ecotoxicol Environ Saf ; 147: 926-934, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28985654

RESUMO

Endocrine disrupting compounds (EDCs) have the potential to alter fish reproduction at various levels of organization. The aim of this study was to assess the impact of a natural environment with heavily anthropogenic influence on the physiological processes involved in reproduction in the freshwater fish lambari (Astyanax fasciatus) using different biomarkers. Adult males and females were collected in different seasons from two distinct sites in the same watershed: Ponte Nova Reservoir (PN) considered a pristine or small anthropogenic influence reference point; and Billings Reservoir (Bil), subjected to a large anthropogenic impact. Biological indices, such as hepatosomatic index and gonadosomatic index (GSI), gonadal histomorphology, fecundity, and biomarkers such as plasma levels of estradiol (E2) as well as hepatic gene expression of its alfa nuclear receptor (ERα), were analyzed. Hepatic vitellogenin (VTG) gene expression was evaluated in both sexes, as an indicator of xenoestrogen exposure. Females collected at PN presented a typical annual variation reflected in GSI, whereas for those sampled at Bil the index did not change through the seasons. The higher concentration of E2 in males collected at Bil during spring/2013, together with the detection of VTG gene expression, suggest the presence of EDCs in the water. These EDCs may have also influenced fecundity of females from Bil, which was higher during winter and spring/2013. Gene expression of ERα and ovarian morphology did not differ between fish from both sites. Water conditions from Bil reservoir impacted by anthropic activity clearly interfered mainly with biomarkers of biological effect such as plasma E2 levels and absolute and relative fecundity, but also altered biomarkers of exposure as VTG gene expression. These facts support the notion that waterborne EDCs are capable of causing estrogenic activity in A. fasciatus.


Assuntos
Characidae/metabolismo , Disruptores Endócrinos/toxicidade , Monitoramento Ambiental/métodos , Gônadas/efeitos dos fármacos , Organogênese/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Biomarcadores/metabolismo , Brasil , Characidae/crescimento & desenvolvimento , Disruptores Endócrinos/análise , Estradiol/metabolismo , Feminino , Fertilidade/efeitos dos fármacos , Água Doce/química , Expressão Gênica/efeitos dos fármacos , Gônadas/crescimento & desenvolvimento , Gônadas/patologia , Masculino , Reprodução/efeitos dos fármacos , Estações do Ano , Vitelogeninas/metabolismo , Poluentes Químicos da Água/análise
19.
Neotrop. ichthyol ; 16(1): e170135, 2018. tab
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-895131

RESUMO

Data on 15 novel microsatellite loci from the Neotropical fish Bryconamericus aff. iheringii are presented here. Analyses of 32 individuals from four different streams revealed 192 different alleles, ranging from four to 32 alleles per locus (mean of 12.8 per locus). Observed and expected heterozygosities ranged from 0.094 to 0.813 and 0.205 to 0.952, respectively. These loci showed high polymorphic information content and will be a resource for genetic studies of B. aff. iheringii. Furthermore, several loci also amplified other small Neotropical Characidae (Piabarchus stramineus and Piabina argentea) and should be useful for these species.(AU)


Um total de quinze novos locos microssatélites é aqui apresentado para o pequeno peixe Neotropical Bryconamericus aff. iheringii. A análise de 32 indivíduos provenientes de quatro ribeirões diferentes revelou 192 alelos diferentes, variando de quatro a 32 alelos por loco (média de 12,8 por loco), e heterozigozidades observada e esperada variando de 0,094 a 0,813 e 0,205 a 0,952, respectivamente. O conjunto de locos obtido mostrou alto conteúdo de informação polimórfica e bom potencial para estudos genéticos de B. aff. iheringii, além disso vários locos amplificaram para outras espécies de pequenos Characidae neotropicais (Piabarchus stramineus and Piabina argentea).(AU)


Assuntos
Animais , Characidae/crescimento & desenvolvimento , Variação Genética/genética , Biomarcadores/análise
20.
Zygote ; 25(6): 711-718, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29082857

RESUMO

The aim of this study was to describe, for the first time, the embryogenesis and larval growth of the Paraitinga Brycon nattereri Günther, 1864 reared in captivity. After artificial fertilization, eggs were incubated at constant temperature (~19°C) and collected every 15 min during the first 3 h and then every 3 h until hatching. Five larvae were collected daily over 15 days for evaluation of the length, yolk sac volume and specific growth rate. The following stages of embryonic development were identified: zygote, cleavage, gastrula, segmentation and larval. The hatching occurred after 50-54 h, with larvae poorly developed and fully depigmented, devoid of mouth and swimming capacity, presenting 6.32 mm total length and 3.64 mm3 yolk sac volume. The mouth opening was observed between days 3-4 after hatching. The yolk sac absorption was slow during the first 3 days, increasing sharply after this period, being completed on the day 11. During this period there was a decrease in the larval growth rate. After yolk sac absorption, an increase in the growth rate was observed that coincided with the start of exogenous feeding. Cannibalism was not observed during the 15 days of evaluation. The initial development of B. nattereri was slow and poorly developed larvae in relation to other Brycon species, certainly due to the lower temperature required for egg incubation and larval rearing. Other studies are needed in order to develop techniques to improve the methods of incubating eggs and feeding larvae.


Assuntos
Criação de Animais Domésticos/métodos , Characidae/crescimento & desenvolvimento , Embrião não Mamífero/citologia , Desenvolvimento Embrionário/fisiologia , Larva/crescimento & desenvolvimento , Animais , Characidae/embriologia , Embrião não Mamífero/fisiologia , Fertilização In Vitro
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