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1.
Braz. j. biol ; 83: e250003, 2023. tab, graf
Artigo em Inglês | MEDLINE, LILACS, VETINDEX | ID: biblio-1339392

RESUMO

Abstract This study estimated the length-weight relationships of 16 fish species occurring close to the shores of sandy beaches along the lower Negro River basin, Brazilian Amazon. The specimens were captured for one day each month, in October to November 2016, early in the morning and early evening, using trawl net (20 m taken for standard length (SL - 0.1 cm precision) and total weight (TW - 0.01 g precision). The parameters a and b of the equation WT = a.LTb were estimated. The a values ranged from 0.0018 to 0.0226 and b values ranged from 2.5271 to 3.3244. This study also provides new data on of maximum lengths for six species, Amazonsprattus scintilla, Brycon pesu, Moenkhausia megalops, Pachyurus paucirastrus, Reganella depressa and Trachydoras microstomus, and new reports of the LWRs parameters of 15 fish species.


Resumo Este estudo estimou as relações comprimento-peso de 16 espécies de peixes que ocorrem às margens de praias arenosas ao longo da bacia do baixo Rio Negro, Amazônia brasileira. As espécies foram capturadas durante um dia de cada mês, de outubro a novembro de 2016, no início da manhã e no início da noite, usando rede de cerco (20 m de comprimento e 3,5 m de altura, 5 malha mm entre nós opostos). As medidas foram feitas para comprimento padrão (SL - precisão de 0,1 cm) e peso total (TW - precisão de 0,01 g). Os parâmetros a e b da equação WT = a.LTb foram estimados. Os valores de a variaram de 0,0018 a 0,0226 e os valores de b variaram de 2,5271 a 3,3244. Este estudo também fornece novos dados sobre comprimentos máximos para seis espécies, Amazonsprattus scintilla, Brycon pesu, Moenkhausia megalops, Pachyurus paucirastrus, Reganella depressa e Trachydoras microstomus, e novos reportes dos parâmetros da LWRs de 15 espécies de peixes.


Assuntos
Animais , Perciformes , Caraciformes , Characidae , Brasil , Rios
2.
Braz. j. biol ; 83: e249158, 2023. graf
Artigo em Inglês | MEDLINE, LILACS, VETINDEX | ID: biblio-1339346

RESUMO

Abstract The knowledge of the testicular and ovarian morphology of a particular fish species is of paramount importance. Such analyze enables the development of studies and techniques aiming the improvement of their reproduction, management, commercialization and even their conservation. This study performed the ovarian and testicular characterization of the ornamental Amazon fish Serrapinnus kriegi. A total of three males and three females had their gonads analyzed by optical microscopy. Females present ovaries filled with oocytes in asynchronous development, indicating partial spawning in the species. Moreover, the micropyle and micropilar cell formation was observed in primary growing oocytes, representing a precocious oocyte development; and the zona radiata in the final vitellogenic oocytes is thicker than other related species, evidencing the development of a better protection to the embryos in function of the waters' turbulence that characterize it spawning sites in the Amazonian streams. The male specimens' present anastomosed tubular testes with unrestricted spermatogonia spread along the entire seminiferous tubules. The present data elucidate the dynamic of spermatogenesis and oogenesis of an ornamental Amazonian species, through the description of the male and female germ cells development.


Resumo O conhecimento da morfologia testicular e ovariana de uma determinada espécie de peixe é de suma importância, pois através destas análises é possível o desenvolvimento de estudos e técnicas visando o melhoramento de sua reprodução, manejo e comercialização e até mesmo auxiliar em sua conservação. Este estudo realizou a caracterização ovariana e testicular do peixe Amazônico ornamental Serrapinnus kriegi. Um total de três machos e três fêmeas tiveram suas gônadas analisadas através de microscopia óptica. As fêmeas apresentam ovários preenchidos por oócitos em desenvolvimento assincrônico, indicando desova parcelada da espécie. Além disso, observou-se a formação de micrópila e célula micropilar em oócitos em crescimento primário, representando o desenvolvimento precoce do oócito; a zona radiata nos oócitos vitelogênicos finais é mais espessa em comparação a outras espécies relacionadas, evidenciando o desenvolvimento de uma melhor proteção aos embriões, em função das águas turbulentas que caracterizam seu local de desova nos córregos amazônicos. Os machos apresentam testículos do tipo tubular anastomosado com espermatogônias irrestritas, espalhadas por todo o túbulo seminífero. Os dados apresentados elucidam a dinâmica da espermatogênese e oogênese de uma espécie de peixe ornamental amazônica, por meio da descrição das células germinativas masculinas e femininas.


Assuntos
Animais , Masculino , Feminino , Characidae , Oócitos , Oogênese , Ovário , Testículo , Gônadas
3.
Sci Rep ; 12(1): 10115, 2022 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-35710938

RESUMO

Cell lines have become an integral resource and tool for conducting biological experiments ever since the Hela cell line was first developed (Scherer et al. in J Exp Med 97:695-710, 1953). They not only allow detailed investigation of molecular pathways but are faster and more cost-effective than most in vivo approaches. The last decade saw many emerging model systems strengthening basic science research. However, lack of genetic and molecular tools in these newer systems pose many obstacles. Astyanax mexicanus is proving to be an interesting new model system for understanding metabolic adaptation. To further enhance the utility of this system, we developed liver-derived cell lines from both surface-dwelling and cave-dwelling morphotypes. In this study, we provide detailed methodology of the derivation process along with comprehensive biochemical and molecular characterization of the cell lines, which reflect key metabolic traits of cavefish adaptation. We anticipate these cell lines to become a useful resource for the Astyanax community as well as researchers investigating fish biology, comparative physiology, and metabolism.


Assuntos
Characidae , Adaptação Fisiológica/genética , Animais , Evolução Biológica , Cavernas , Characidae/fisiologia , Células HeLa , Humanos , Fígado
4.
Elife ; 112022 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35703366

RESUMO

Insights from organisms, which have evolved natural strategies for promoting survivability under extreme environmental pressures, may help guide future research into novel approaches for enhancing human longevity. The cave-adapted Mexican tetra, Astyanax mexicanus, has attracted interest as a model system for metabolic resilience, a term we use to denote the property of maintaining health and longevity under conditions that would be highly deleterious in other organisms (Figure 1). Cave-dwelling populations of Mexican tetra exhibit elevated blood glucose, insulin resistance and hypertrophic visceral adipocytes compared to surface-dwelling counterparts. However, cavefish appear to avoid pathologies typically associated with these conditions, such as accumulation of advanced-glycation-end-products (AGEs) and chronic tissue inflammation. The metabolic strategies underlying the resilience properties of A. mexicanus cavefish, and how they relate to environmental challenges of the cave environment, are poorly understood. Here, we provide an untargeted metabolomics study of long- and short-term fasting in two A. mexicanus cave populations and one surface population. We find that, although the metabolome of cavefish bears many similarities with pathological conditions such as metabolic syndrome, cavefish also exhibit features not commonly associated with a pathological condition, and in some cases considered indicative of an overall robust metabolic condition. These include a reduction in cholesteryl esters and intermediates of protein glycation, and an increase in antioxidants and metabolites associated with hypoxia and longevity. This work suggests that certain metabolic features associated with human pathologies are either not intrinsically harmful, or can be counteracted by reciprocal adaptations. We provide a transparent pipeline for reproducing our analysis and a Shiny app for other researchers to explore and visualize our dataset.


Assuntos
Antioxidantes , Characidae , Envelhecimento , Animais , Evolução Biológica , Humanos , Metaboloma , Açúcares
5.
Nat Genet ; 54(5): 684-693, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35551306

RESUMO

Cis-regulatory changes are key drivers of adaptative evolution. However, their contribution to the metabolic adaptation of organisms is not well understood. Here, we used a unique vertebrate model, Astyanax mexicanus-different morphotypes of which survive in nutrient-rich surface and nutrient-deprived cave waters-to uncover gene regulatory networks underlying metabolic adaptation. We performed genome-wide epigenetic profiling in the liver tissues of Astyanax and found that many of the identified cis-regulatory elements (CREs) have genetically diverged and have differential chromatin features between surface and cave morphotypes, while retaining remarkably similar regulatory signatures between independently derived cave populations. One such CRE in the hpdb gene harbors a genomic deletion in cavefish that abolishes IRF2 repressor binding and derepresses enhancer activity in reporter assays. Selection of this mutation in multiple independent cave populations supports its importance in cave adaptation, and provides novel molecular insights into the evolutionary trade-off between loss of pigmentation and adaptation to food-deprived caves.


Assuntos
Characidae , Aclimatação , Adaptação Fisiológica/genética , Animais , Evolução Biológica , Cavernas , Characidae/genética , Characidae/metabolismo , Mutação
6.
Zootaxa ; 5116(2): 253-266, 2022 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-35391336

RESUMO

A new species of Hyphessobrycon presenting dimorphic males is described from the western Amazon basin in Brazil, Colombia, Ecuador, and Peru. The new species has been mistakenly identified in the literature with the non-congener Hemigrammus marginatus, with which shares a similar color pattern by presenting dark patches of dark pigmentation on caudal-fin lobes. It can be distinguished from the latter species, as well as from Hemigrammus durbinae, and two similar congeners, Hyphessobrycon diancistrus and Hy. otrynus, all of which sharing the same caudal fin color pattern, by the combination of presenting a dark patch of pigmentation on the dorsal fin, a single large anal-fin hook at the last unbranched anal-fin ray in mature males, and a moderately high body depth (22.432.5 % SL, mean 28.4 %). The new species is more similar to Hyphessobrycon diancistrus, which is putatively its closely related taxon. A putative close relationship with Hyphessobrycon otrynus, and with a non-congener presenting a distinct color pattern but sharing a similar sexual dimorphism on anal-fin hook morphology, Hemigrammus boesemani, is suggested.


Assuntos
Characidae , Caraciformes , Animais , Characidae/anatomia & histologia , Masculino , Pigmentação , Rios , Caracteres Sexuais
7.
Development ; 149(7)2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35388410

RESUMO

The vertebrate retinas originate from a specific anlage in the anterior neural plate called the eye field. Its identity is conferred by a set of 'eye transcription factors', whose combinatorial expression has been overlooked. Here, we use the dimorphic teleost Astyanax mexicanus, which develops proper eyes in the wild type and smaller colobomatous eyes in the blind cavefish embryos, to unravel the molecular anatomy of the eye field and its variations within a species. Using a series of markers (rx3, pax6a, cxcr4b, zic1, lhx2, emx3 and nkx2.1a), we draw a comparative 3D expression map at the end of gastrulation/onset of neurulation, which highlights hyper-regionalization of the eye field into sub-territories of distinct sizes, shapes, cell identities and combinatorial gene expression levels along the three body axes. All these features show significant variations in the cavefish natural mutant. We also discover sub-domains within the prospective telencephalon and characterize cell identities at the frontiers of the eye field. We propose putative fates for some of the characterized eye-field subdivisions, and suggest the existence of a trade-off between some subdivisions in the two Astyanax morphs on a micro-evolutionary scale.


Assuntos
Characidae , Placa Neural , Animais , Evolução Biológica , Olho , Gastrulação , Estudos Prospectivos , Retina
8.
An Acad Bras Cienc ; 94(4): e20201425, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35442265

RESUMO

Ten endoparasite species found in Pygocentrus piraya, which is a piranha species native to São Francisco river, were collected from 108 fish caught in Três Marias reservoir in 2004 and 2005, namely: Digenea - Austrodiplostomum sp. (metacercariae); Eucestoda - Proteocephalidae gen. sp. (plerocercoids); and Nematoda - Procamallanus (Spirocamallanus) inopinatus, Cystidicoloides fischeri and Capillostrongyloides sentinosa (adults); Spinitectus rodolphiheringi (juvenile); Hysterothylacium sp., Contracaecum sp. Type 1, Spiroxys sp. and Goezia sp. (larvae). In helminth fauna, P. (S.) inopinatus has shown higher prevalence and dominance. Fish sex has influenced the prevalence of Hysterothylacium sp., which was higher in female specimens. Longer total length of fish has positively influenced the abundance of C. sentinosa and Hysterothylacium sp.. The rainy season has favored parasitic indices, mainly P. (S.) inopinatus abundance, as well C. sentinosa and Hysterothylacium sp. prevalence and abundance. There were co-occurrences between adult and some larval nematodes. Endemic piranhas, as well as final hosts, are important intermediate and/or paratenic hosts, given the relevant number of larvae (proteocephalideans and nematodes) of heteroxene cycle found in them. Proteocephalidae gen. sp., C. sentinosa, Hysterothylacium sp., Contracaecum sp. Type 1, Goezia sp. and S. rodolphiheringi are new records parasitizing P. piraya in São Francisco basin.


Assuntos
Cestoides , Characidae , Caraciformes , Doenças dos Peixes , Helmintos , Nematoides , Animais , Brasil/epidemiologia , Caraciformes/parasitologia , Feminino , Doenças dos Peixes/epidemiologia , Doenças dos Peixes/parasitologia , Larva , Rios
9.
Curr Biol ; 32(10): 2272-2280.e6, 2022 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-35390280

RESUMO

Nutrient availability varies seasonally and spatially in the wild. While many animals, such as hibernating animals or migrating birds, evolved strategies to overcome periods of nutrient scarcity,1,2 the cellular mechanisms of these strategies are poorly understood. Cave environments represent an example of nutrient-deprived environments, since the lack of sunlight and therefore primary energy production drastically diminishes the nutrient availability.3 Here, we used Astyanax mexicanus, which includes river-dwelling surface fish and cave-adapted cavefish populations, to study the genetic adaptation to nutrient limitations.4-9 We show that cavefish populations store large amounts of fat in different body regions when fed ad libitum in the lab. We found higher expression of lipogenesis genes in cavefish livers when fed the same amount of food as surface fish, suggesting an improved ability of cavefish to use lipogenesis to convert available energy into triglycerides for storage into adipose tissue.10-12 Moreover, the lipid metabolism regulator, peroxisome proliferator-activated receptor γ (Pparγ), is upregulated at both transcript and protein levels in cavefish livers. Chromatin immunoprecipitation sequencing (ChIP-seq) showed that Pparγ binds cavefish promoter regions of genes to a higher extent than surface fish and inhibiting Pparγ in vivo decreases fat accumulation in A. mexicanus. Finally, we identified nonsense mutations in per2, a known repressor of Pparγ, providing a possible regulatory mechanism of Pparγ in cavefish. Taken together, our study reveals that upregulated Pparγ promotes higher levels of lipogenesis in the liver and contributes to higher body fat accumulation in cavefish populations, an important adaptation to nutrient-limited environments.


Assuntos
Characidae , PPAR gama , Adaptação Fisiológica/genética , Animais , Evolução Biológica , Cavernas , Characidae/genética , Characidae/metabolismo , Lipogênese/genética , PPAR gama/genética , PPAR gama/metabolismo
10.
Zebrafish ; 19(2): 71-80, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35394373

RESUMO

The genus Oligosarcus currently comprises 24 valid species distributed in the major river basins of South America. In this group, nine species were cytogenetically investigated, and found to share a diploid number of 50 chromosomes. Despite the conservation of the diploid number, variations in the karyotypic formula, number and position of the nucleolar organizer regions, and longitudinal bands have been described between both species and populations. In this study, we present cytogenetic and molecular data from Oligosarcus pintoi specimens from the Keller River, a tributary of the Ivaí River (Upper Paraná basin), using DNA barcoding and cytogenetic markers (C-band, silver-stained nucleolar organizer regions, and fluorescence in situ hybridization of 18S and 5S rDNA). The genetic inferences reached after analyzing the cytochrome c oxidade subunit 1 gene allowed us to confirm the identity of the individuals with 2n = 50 chromosomes. However, one specimen contained a medium subtelocentric supernumerary chromosome (2n = 51). This is the second record of additional chromosomes in O. pintoi, thereby confirming the existence of a supernumerary chromosome in allopatric populations of this species, a fact that demonstrates an evolutionary path that is divergent from other populations and/or species of Oligosarcus analyzed so far, contributing to the karyotypic diversification of the group.


Assuntos
Characidae , Animais , Characidae/genética , DNA Ribossômico/genética , Hibridização in Situ Fluorescente , Cariótipo , Cariotipagem , Peixe-Zebra/genética
11.
J Morphol ; 283(6): 815-826, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35373392

RESUMO

The cardinal tetra Paracheirodon axelrodi belongs to the family Characidae, an economically important and morphologically diverse family of fishes. Information on the olfactory system of this species is scattered and scarce. Among teleost fishes, differences exist in the shape, number, and arrangement of the olfactory lamellae, in the distribution of the sensory and nonsensory epithelium, as well as in the abundance of various receptor cell types. Here, an anatomical and morphological description of the olfactory system was carried out using light microscopic histology, immunohistochemistry, scanning electron microscopy, and transmission electron microscopy. P. axelrodi is a ditremous and isosmat species. It has an arrow-shaped olfactory rosette arrangement. The olfactory epithelium is covering the 12-14 lamellae of the olfactory rosette and, using scanning electron microscopy, we observed that the apical surface of the olfactory epithelium carries a dense layer of mucus. Based on the histological, immunohistochemical, and ultrastructural descriptions, all characteristic sensory and nonsensory cell types of the olfactory epithelium of teleost fish were identified. Three types of olfactory receptor neurons were identified: ciliated, microvilli, and crypt cells. The distribution of sensory and nonsensory cell types is like that described in Aphyocharax anisitsi, another species of the Characidae family. A. anisitsi inhabits slow-flowing water bodies with high-density vegetation such as P. axelrodi.


Assuntos
Characidae , Caraciformes , Neurônios Receptores Olfatórios , Animais , Characidae/anatomia & histologia , Microscopia Eletrônica de Varredura , Mucosa Olfatória
12.
PLoS One ; 17(4): e0265894, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35385509

RESUMO

Fish display a remarkable diversity of social behaviors, both within and between species. While social behaviors are likely critical for survival, surprisingly little is known about how they evolve in response to changing environmental pressures. With its highly social surface form and multiple populations of a largely asocial, blind, cave-dwelling form, the Mexican tetra, Astyanax mexicanus, provides a powerful model to study the evolution of social behavior. Here we use motion tracking and analysis of swimming kinematics to quantify social swimming in four Astyanax mexicanus populations. In the light, surface fish school, maintaining both close proximity and alignment with each other. In the dark, surface fish no longer form coherent schools, however, they still show evidence of an attempt to align and maintain proximity when they find themselves near another fish. In contrast, cavefish from three independently-evolved populations (Pachón, Molino, Tinaja) show little preference for proximity or alignment, instead exhibiting behaviors that suggest active avoidance of each other. Two of the three cave populations we studied also slow down when more fish are present in the tank, a behavior which is not observed in surface fish in light or the dark, suggesting divergent responses to conspecifics. Using data-driven computer simulations, we show that the observed reduction in swimming speed is sufficient to alter the way fish explore their environment: it can increase time spent exploring away from the walls. Thus, the absence of schooling in cavefish is not merely a consequence of their inability to see, but may rather be a genuine behavioral adaptation that impacts the way they explore their environment.


Assuntos
Evolução Biológica , Characidae , Animais , Fenômenos Biomecânicos , Cavernas , Characidae/fisiologia , Interação Social
13.
PLoS Comput Biol ; 18(3): e1009437, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35235565

RESUMO

In moving animal groups, social interactions play a key role in the ability of individuals to achieve coordinated motion. However, a large number of environmental and cognitive factors are able to modulate the expression of these interactions and the characteristics of the collective movements that result from these interactions. Here, we use a data-driven fish school model to quantitatively investigate the impact of perceptual and cognitive factors on coordination and collective swimming patterns. The model describes the interactions involved in the coordination of burst-and-coast swimming in groups of Hemigrammus rhodostomus. We perform a comprehensive investigation of the respective impacts of two interactions strategies between fish based on the selection of the most or the two most influential neighbors, of the range and intensity of social interactions, of the intensity of individual random behavioral fluctuations, and of the group size, on the ability of groups of fish to coordinate their movements. We find that fish are able to coordinate their movements when they interact with their most or two most influential neighbors, provided that a minimal level of attraction between fish exist to maintain group cohesion. A minimal level of alignment is also required to allow the formation of schooling and milling. However, increasing the strength of social interactions does not necessarily enhance group cohesion and coordination. When attraction and alignment strengths are too high, or when the heading random fluctuations are too large, schooling and milling can no longer be maintained and the school switches to a swarming phase. Increasing the interaction range between fish has a similar impact on collective dynamics as increasing the strengths of attraction and alignment. Finally, we find that coordination and schooling occurs for a wider range of attraction and alignment strength in small group sizes.


Assuntos
Characidae , Comportamento Social , Animais , Comportamento Animal , Cognição , Modelos Biológicos , Instituições Acadêmicas , Natação
14.
Sci Rep ; 12(1): 3735, 2022 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-35260642

RESUMO

Animals inhabiting extreme environments allow the powerful opportunity to examine adaptive evolution in response to diverse pressures. One such pressure is reduced oxygen, commonly present at high-altitude and subterranean environments. Cave-dwelling animals must also deal with darkness and starvation, both of which have been rigorously studied as key forces driving the evolution of cave-associated traits. Interestingly, hypoxia as an environmental pressure has received less attention. Here we examined putatively adaptive phenotypes evolving in a freshwater teleost fish, Astyanax mexicanus, which includes both surface- and cave-dwelling forms. This model system also provides the opportunity to identify convergent responses to hypoxia, owing to the presence of numerous natural and independently-colonised cave populations, alongside closely-related surface conspecifics. The focus of this study is hemoglobin, an essential molecule for oxygen transport and delivery. We found that multiple cave populations harbor a higher concentration of hemoglobin in their blood, which is coincident with an increase in cave morph erythrocyte size compared to surface fish. Interestingly, both cave and surface morphs have comparable numbers of erythrocytes per unit of blood, suggesting elevated hemoglobin is not due to overproduction of red blood cells. Alternatively, owing to an increased cell area of erythrocytes in cavefish, we reason that they contain more hemoglobin per erythrocyte. These findings support the notion that cavefish have adapted to hypoxia in caves through modulation of both hemoglobin production and erythrocyte size. This work reveals an additional adaptive feature of Astyanax cavefish, and demonstrates that coordinated changes between cellular architecture and molecular changes are necessary for organisms evolving under intense environmental pressure.


Assuntos
Characidae , Oxigênio , Adaptação Fisiológica/genética , Animais , Evolução Biológica , Cavernas , Characidae/fisiologia , Eritrócitos , Hipóxia
15.
Mol Phylogenet Evol ; 171: 107462, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35358689

RESUMO

Characinae is one of the most species-rich subfamilies of Characidae and holds special taxonomic importance because it includes Charax, type-genus of Characidae and Characiformes. Currently, the monophyly and the hypotheses of intergeneric and interspecific relationships of Characinae are based on a few morphological and molecular studies but all with low species coverage. Given their diversity, taxonomic importance, and the lack of a taxon-dense phylogeny, we sought to buttress the systematic understanding of Characinae collecting DNA sequence data from ultraconserved elements (UCEs) of the genome from 98 specimens covering 57 species (61%) plus 17 characiforms as outgroups. We used maximum likelihood, Bayesian inference, and coalescent-based species tree approaches and the resulting phylogeny with 1,300 UCE loci (586,785 characters) reinforced the monophyly of the subfamily as well as of six genera: Acestrocephalus, Charax, Cynopotamus, Galeocharax, Phenacogaster, and Roeboides. The phylogeny provides a hypothesis of intergeneric and interspecific relationships for the subfamily with Phenacogaster sister to all genera, and Acanthocharax sister to Cynopotamini (Cynopotamus (Acestrocephalus Galeocharax)) and Characini (Charax Roeboides). We propose a new tribe Acanthocharacini to allocate Acanthocharax, two subclades for Phenacogaster, two for Cynopotamus, three for Charax, and reinforced the four subclades for Roeboides previously identified by morphological studies. Additionally, we generated a time-calibrated phylogeny for Characinae that suggested an initial diversification during the Miocene at around 19 million years ago and discussed historical biogeographic events for major subclades. The results obtained here will contribute to the development of further research on the evolutionary processes modulating species diversification in Characinae.


Assuntos
Characidae , Caraciformes , Animais , Teorema de Bayes , Evolução Biológica , Filogenia , Análise de Sequência de DNA
16.
Mol Biol Evol ; 39(4)2022 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-35277964

RESUMO

Sinocyclocheilus represents a rare, freshwater teleost genus endemic to China that comprises the river-dwelling surface fish and the cave-dwelling cavefish. Using a combinatorial approach of quantitative lipidomics and mass-spectrometry imaging (MSI), we demonstrated that neural compartmentalization of lipid distribution and lipid metabolism is associated with the evolution of troglomorphic traits in Sinocyclocheilus. Attenuated docosahexaenoic acid (DHA) biosynthesis via the Δ4 desaturase pathway led to reductions in DHA-phospholipids in cavefish cerebellum. Instead, cavefish accumulates arachidonic acid-phospholipids that may disfavor retinotectal arbor growth. Importantly, MSI of sulfatides coupled with immunostaining of myelin basic protein and transmission electron microscopy images of hindbrain axons revealed demyelination in cavefish raphe serotonergic neurons. Demyelination in cavefish parallels the loss of neuroplasticity governing social behavior such as aggressive dominance. Outside the brain, quantitative lipidomics and qRT-PCR revealed systemic reductions in membrane esterified DHAs in the liver, attributed to suppression of genes along the Sprecher pathway (elovl2, elovl5, and acox1). Development of fatty livers was observed in cavefish; likely mediated by an impeded mobilization of storage lipids, as evident in the diminished expressions of pnpla2, lipea, lipeb, dagla, and mgll; and suppressed ß-oxidation of fatty acyls via both mitochondria and peroxisomes as reflected in the reduced expressions of cpt1ab, hadhaa, cpt2, decr1, and acox1. These neurological and systemic metabolic adaptations serve to reduce energy expenditure, forming the basis of recessive evolution that eliminates nonessential morphological and behavioral traits and giving cavefish a selective advantage to thrive in caves where proper resource allocation becomes a major determinant of survival.


Assuntos
Characidae , Cyprinidae , Doenças Desmielinizantes , Animais , Evolução Biológica , Cavernas , Characidae/genética , Lipidômica , Redes e Vias Metabólicas , Fosfolipídeos
17.
J Fish Biol ; 100(5): 1245-1263, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35266159

RESUMO

Predictions about global warming have raised interest in assessing whether ectothermic organisms will be able to adapt to these changes. Understanding the physiological mechanisms and metabolic adjustment capacity of fish subjected to heat stress can provide subsidies that may contribute to decision-making in relation to ecosystems and organisms subjected to global climate change. This study investigated the antioxidant defence system and energy metabolism of carbohydrate and protein responses in the gill, liver and kidney tissues of Psalidodon bifasciatus (Garavello & Sampaio 2010), a Brazilian freshwater fish used in aquaculture and in biological studies, following exposure to heat shock at 31°C for 2, 6, 12, 24 and 48 h. The fish presented signs of stress in all tissues tested, as evidenced by increased lipid peroxidation concentration at 2 h and phosphofructokinase, hexokinase and malate dehydrogenase activity at 48 h in the gills; increased glutathione-S-transferase activity at 12 h, citrate synthase activity at 24 h and concentration of reduced glutathione (GSH) concentration at 12 and 48 h in the liver; and through increased activity of superoxide dismutase at 48 h, glutathione reductase at 24 h, glucose-6-phosphate dehydrogenase at 48 h and concentration of GSH at 24 h in the kidney. In the kidneys, changes in the antioxidant system were more prominent, whereas in the gills, there were greater changes in the carbohydrate metabolism. These results indicated the importance of glycolysis and aerobic metabolism in the gills, aerobic metabolism in the liver and pentose-phosphate pathway in the kidneys during homeostasis. The biomarker response was tissue specific, with the greatest number of biomarkers altered in the gills, followed by those in the kidneys and liver.


Assuntos
Antioxidantes , Characidae , Animais , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Characidae/metabolismo , Ecossistema , Metabolismo Energético , Brânquias/metabolismo , Glutationa/metabolismo , Glutationa/farmacologia , Glutationa Peroxidase/metabolismo , Glutationa Peroxidase/farmacologia , Resposta ao Choque Térmico , Peroxidação de Lipídeos , Fígado/metabolismo , Estresse Oxidativo , Superóxido Dismutase/metabolismo , Superóxido Dismutase/farmacologia
18.
Mol Biol Rep ; 49(3): 1741-1748, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35023005

RESUMO

BACKGROUND: The taxonomic status of Knodu in the family Characidae is not yet clear. This study aimed to address this by sequencing and annotating Knodu borki Zarske, 2008. MATERIALS AND RESULTS: K. borki Zarske, 2008 was sequenced using a Hiseq platform and the complete mitogenome was assembled in SPAdes v3.15.2 and SOAPdenovo2 v.2.01. The mitogenome of K. borki from Guangzhou, the first sequenced species of the genus Knodu, is 16,837 bp in length and contains 13 protein-coding genes (PCGs), two ribosomal (r) RNAs, 22 transfer (t) RNAs, and one D-loop. Among these 37 genes, 28 are encoded by the heavy strand, while nine are encoded by the light strand. Twenty-one of the tRNAs can form typical cloverleaf secondary structures, except tRNA-Ser1, which lacks dihydrouridine arms. All PCGs have the same start codon (ATG), with the exception of COI (GTG). Four PCGs (ND1, ATP8, ND4L, and ND5) have TAA as the stop codon, ND6 has TAG as the stop codon, COI has AGG as the stop codon, and the remaining seven genes have incomplete stop codons of TA-/T-(ND2, COII, COIII, ND3, ND4, and Cyt b as T-, ATP6 as TA-). Phylogenetic analysis showed that K. borki belongs to the family Characidae. CONCLUSIONS: Our findings demonstrate that K. borki belongs to the family Characidae, due to consistency with the morphological identification. This study provides molecular information for further research on the phylogeny of the genus Knodus and for analyses of the taxonomic status of Characidae.


Assuntos
Characidae , Cipriniformes , Genoma Mitocondrial , Animais , Composição de Bases , Characidae/genética , Cipriniformes/genética , Genoma Mitocondrial/genética , Genômica , Filogenia , RNA Ribossômico/genética , RNA de Transferência/genética , Análise de Sequência de DNA
19.
Elife ; 112022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34984980

RESUMO

Dark caves lacking primary productivity can expose subterranean animals to hypoxia. We used the surface-dwelling (surface fish) and cave-dwelling (cavefish) morphs of Astyanax mexicanus as a model for understanding the mechanisms of hypoxia tolerance in the cave environment. Primitive hematopoiesis, which is restricted to the posterior lateral mesoderm in other teleosts, also occurs in the anterior lateral mesoderm in Astyanax, potentially pre-adapting surface fish for hypoxic cave colonization. Cavefish have enlarged both hematopoietic domains and develop more erythrocytes than surface fish, which are required for normal development in both morphs. Laboratory-induced hypoxia suppresses growth in surface fish but not in cavefish. Both morphs respond to hypoxia by overexpressing hypoxia-inducible factor 1 (hif1) pathway genes, and some hif1 genes are constitutively upregulated in normoxic cavefish to similar levels as in hypoxic surface fish. We conclude that cavefish cope with hypoxia by increasing erythrocyte development and constitutive hif1 gene overexpression.


Assuntos
Adaptação Fisiológica/genética , Cavernas , Characidae/genética , Meio Ambiente , Eritrócitos/fisiologia , Hipóxia/genética , Animais , Evolução Biológica , Characidae/sangue , Characidae/imunologia , Feminino , Hipóxia/sangue , Masculino
20.
Bull Environ Contam Toxicol ; 108(4): 678-684, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34773480

RESUMO

In the present study, water physicochemical and microbiological parameters, as well as bioassays using Allium cepa L. seeds and the fish species Astyanax jacuhiensis were used to assess the water quality of two rivers - Ilha River and Paranhana River -, located in southern Brazil. Water samples were collected at the source and mouth of the rivers and then, laboratory experiments were performed. The results evidenced high levels of aluminum and iron in water samples collected at the four sampling sites. The micronucleus (MN) test in fish showed significant difference in the frequencies of nuclear abnormalities (NA) in the mouth of the Paranhana River in comparison to control group in one sampling period, whereas the A. cepa test evidenced significant spatial differences in cytotoxicity between the source and mouth of both rivers. Therefore, these data evidence the poor water quality of the rivers studied as well as the potential toxicity to the aquatic organisms.


Assuntos
Characidae , Poluentes Químicos da Água , Animais , Bioensaio , Brasil , Monitoramento Ambiental/métodos , Rios/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade , Qualidade da Água
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