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1.
Nat Commun ; 12(1): 1447, 2021 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-33664263

RESUMO

Identifying the genetic factors that underlie complex traits is central to understanding the mechanistic underpinnings of evolution. Cave-dwelling Astyanax mexicanus populations are well adapted to subterranean life and many populations appear to have evolved troglomorphic traits independently, while the surface-dwelling populations can be used as a proxy for the ancestral form. Here we present a high-resolution, chromosome-level surface fish genome, enabling the first genome-wide comparison between surface fish and cavefish populations. Using this resource, we performed quantitative trait locus (QTL) mapping analyses and found new candidate genes for eye loss such as dusp26. We used CRISPR gene editing in A. mexicanus to confirm the essential role of a gene within an eye size QTL, rx3, in eye formation. We also generated the first genome-wide evaluation of deletion variability across cavefish populations to gain insight into this potential source of cave adaptation. The surface fish genome reference now provides a more complete resource for comparative, functional and genetic studies of drastic trait differences within a species.


Assuntos
Adaptação Fisiológica/genética , Characidae/embriologia , Characidae/genética , Olho/embriologia , Herança Multifatorial/genética , Animais , Evolução Biológica , Cavernas , Mapeamento Cromossômico , Evolução Molecular , Edição de Genes , Genoma/genética , Proteínas de Homeodomínio/genética , Fosfatases da Proteína Quinase Ativada por Mitógeno/genética , Locos de Características Quantitativas/genética
2.
J Vis Exp ; (168)2021 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-33645574

RESUMO

The Mexican tetra, Astyanax mexicanus, is an emerging model system for studies in development and evolution. The existence of eyed surface (surface fish) and blind cave (cave fish) morphs in this species presents an opportunity to interrogate the mechanisms underlying morphological and behavioral evolution. Cave fish have evolved novel constructive and regressive traits. The constructive changes include increases in taste buds and jaws, lateral line sensory organs, and body fat. The regressive changes include loss or reduction of eyes. melanin pigmentation, schooling behavior, aggression, and sleep. To experimentally interrogate these changes, it is crucial to obtain large numbers of spawned embryos. Since the original A. mexicanus surface fish and cave fish were collected in Texas and Mexico in the 1990s, their descendants have been routinely stimulated to breed and spawn large numbers of embryos bimonthly in the Jeffery laboratory. Although breeding is controlled by food abundance and quality, light-dark cycles, and temperature, we have found that incremental temperature changes play a key role in stimulating maximal spawning. The gradual increase of temperature from 72 °F to 78 °F in the first three days of a breeding week provides two-three consecutive spawning days with maximal numbers of high-quality embryos, which is then followed by a gradual decrease of temperature from 78 °F to 72 °F during the last three days of the spawning week. The procedures shown in this video outline the workflow before and during a laboratory breeding week for incremental temperature stimulated spawning.


Assuntos
Cruzamento , Characidae/fisiologia , Temperatura , Animais , Cavernas , Pigmentação/fisiologia
3.
Exp Parasitol ; 223: 108089, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33639135

RESUMO

The morphological, biological, and molecular characterisation of Cryptosporidium piscine genotype 7 from red-eye tetras (Moenkhausia sanctaefilomenae) are described, and the species name Cryptosporidium abrahamseni n. sp. is proposed. Histological analysis of intestinal tissue identified large numbers of Cryptosporidium organisms along the epithelial lining of the intestine. Sequence and phylogenetic analysis at 18S rRNA (18S) and actin loci conducted on intestinal scrapings revealed that C. abrahamseni n. sp. was genetically distinct from other Cryptosporidium species. At the 18S locus, it was most closely related to C. huwi (3.2% genetic distance) and exhibited genetic distances ranging from 5.9 to 6.5% (C. molnari) to 14.9% (C. scolpthalmi) from all other Cryptosporidium species. At the actin locus, the genetic distances were larger and C. abrahamseni n. sp. exhibited 10.3% genetic distance from C. huwi, and 17.6% (C. molnari) to 28% (C. canis) genetic distance from other Cryptosporidium spp. Phylogenetic analysis of concatenated 18S and actin sequences confirmed that C. abrahamseni n. sp. shares the closest genetic relationship with C. huwi (6.7% genetic distance), while the genetic distance between C. abrahamseni n. sp. and other Cryptosporidium spp. ranged from 12.1% (C. molnari) to 20.4% (C. canis). Based on genetic and histological data, C. abrahamseni n. sp. is validated as a separate species.


Assuntos
Characidae/parasitologia , Criptosporidiose/parasitologia , Cryptosporidium/classificação , Doenças dos Peixes/parasitologia , Enteropatias Parasitárias/veterinária , Actinas/genética , Animais , Evolução Biológica , Criptosporidiose/epidemiologia , Criptosporidiose/patologia , Cryptosporidium/genética , Cryptosporidium/ultraestrutura , Doenças dos Peixes/epidemiologia , Doenças dos Peixes/patologia , Genótipo , Enteropatias Parasitárias/epidemiologia , Enteropatias Parasitárias/parasitologia , Enteropatias Parasitárias/patologia , Intestinos/parasitologia , Intestinos/patologia , Filogenia , Prevalência , RNA Ribossômico 18S/genética , Austrália Ocidental/epidemiologia
4.
Ecotoxicol Environ Saf ; 208: 111601, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33396121

RESUMO

Atrazine (ATZ) is among the most widely used herbicides in the world, and yet it has a potential to contaminate aquatic environments due to pesticide leaching from agricultural areas. In the Neotropical region, studies about the effects of this herbicide in native aquatic wildlife is scarce.Our study aimed at investigating the effects of a 30-day exposure to a commercial atrazine formulation on oxidative stress parameters, histopathology in testis and liver, and hormone levels in males and female of yellow-tailed tetra fish (Astyanax altiparanae). Adults were exposed to low but environmentally relevant concentrations of atrazine as follows: 0 (CTL-control), 0.5 (ATZ0.5), 1 (ATZ1), 2 (ATZ2) and 10 (ATZ10) µg/L. Our results showed decreased GST activity in gills in all groups of exposed animals and increased CAT activity in gills from the ATZ10 group. In the liver, there was an increase in lipid peroxidation in fish from ATZ1 and ATZ2 groups. Histological analysis of the liver showed increased percentage of sinusoid capillaries in ATZ2 fish, increased vascular congestion in ATZ1 and increased leukocyte infiltration in the ATZ10 group. Hepatocyte diameter analysis revealed a decrease in cell size in all groups exposed to ATZ, and a decrease in hepatocyte nucleus diameter in ATZ1, ATZ2 and ATZ10 groups. Endocrine parameters did not show significant changes following ATZ exposure, although an increase of triiodothyronine/thyroxine (T3/T4) ratio was observed in ATZ2 fish. Our results provide evidence that even low, environmentally relevant concentrations of ATZ produced oxidative damage and histological alterations in adult yellow-tailed tetra.


Assuntos
Atrazina/toxicidade , Characidae/metabolismo , Herbicidas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Atrazina/metabolismo , Relação Dose-Resposta a Droga , Feminino , Brânquias/efeitos dos fármacos , Brânquias/metabolismo , Herbicidas/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Masculino , Testículo/efeitos dos fármacos , Testículo/metabolismo , Testículo/patologia , Poluentes Químicos da Água/metabolismo
5.
Parasitol Res ; 120(2): 497-514, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33415390

RESUMO

A novel microsporidial disease was documented in two ornamental fish species, black tetra Gymnocorymbus ternetzi Boulenger 1895 and cardinal tetra Paracheirodon axelrodi Schultz 1956. The non-xenoma-forming microsporidium occurred diffusely in most internal organs and the gill, thus referring to the condition as tetra disseminated microsporidiosis (TDM). The occurrence of TDM in black tetra was associated with chronic mortality in a domestic farmed population, while the case in cardinal tetra occurred in moribund fish while in quarantine at a public aquarium. Histology showed that coelomic visceral organs were frequently necrotic and severely disrupted by extensive infiltrates of macrophages. Infected macrophages were presumed responsible for the dissemination of spores throughout the body. Ultrastructural characteristics of the parasite developmental cycle included uninucleate meronts directly in the host cell cytoplasm. Sporonts were bi-nucleated as a result of karyokinesis and a parasite-produced sporophorous vesicle (SPV) became apparent at this stage. Cytokinesis resulted in two spores forming within each SPV. Spores were uniform in size, measuring about 3.9 ± 0.33 long by 2.0 ± 0.2 µm wide. Ultrastructure demonstrated two spore types, one with 9-12 polar filament coils and a double-layered exospore and a second type with 4-7 polar filament coils and a homogenously electron-dense exospore, with differences perhaps related to parasite transmission mechanisms. The 16S rDNA sequences showed closest identity to the genus Glugea (≈ 92%), though the developmental cycle, specifically being a non-xenoma-forming species and having two spores forming within a SPV, did not fit within the genus. Based on combined phylogenetic and ultrastructural characteristics, a new genus (Fusasporis) is proposed, with F. stethaprioni n. gen. n. sp. as the type species.


Assuntos
Characidae/parasitologia , Doenças dos Peixes/microbiologia , Microsporídios não Classificados/classificação , Microsporídios não Classificados/patogenicidade , Microsporidiose/veterinária , Animais , Animais Domésticos , Characidae/classificação , DNA Ribossômico/genética , Doenças dos Peixes/patologia , Macrófagos/parasitologia , Microsporídios não Classificados/citologia , Microsporídios não Classificados/genética , Microsporidiose/microbiologia , Microsporidiose/patologia , Filogenia , Esporos Fúngicos/citologia , Esporos Fúngicos/patogenicidade
6.
Zootaxa ; 4859(2): zootaxa.4859.2.6, 2020 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-33056200

RESUMO

A new species of Hyphessobrycon Durbin from the Paraná do Urariá system in Central Amazon region, Amazonas state, Brazil, is described. The new species is allocated into the Hyphessobrycon heterorhabdus species-group due to its color pattern, composed by a well-defined, horizontally elongated humeral blotch continuous with a conspicuous midlateral dark stripe that becomes blurred towards the caudal peduncle, and can be distinguished from all other species of the group by possessing humeral blotch and continuous midlateral stripe broad, occupying vertical height equivalent of two scale rows. A tricolored pattern composed dorsally by a red or reddish longitudinal stripe, a middle iridescent, golden or silvery longitudinal stripe, and ventrally by a variably-developed longitudinal dark stripe is identified as a putative additional character shared by the species of the Hyphessobrycon heterorhabdus species-group. The presence of bony hooks in all fins in mature males of some species of the Hyphessobrycon heterorhabdus species-group is also discussed.


Assuntos
Characidae , Caraciformes , Nadadeiras de Animais , Animais , Brasil , Masculino
7.
Zootaxa ; 4852(1): zootaxa.4852.1.1, 2020 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-33056706

RESUMO

Moenkhausia cotinho is redescribed based on the examination of meristic and morphometric data and external morphological characters of specimens from the Amazon and Orinoco basins and from rivers in the Guyana. The species is distinguished from congeners based on the combination of a reticulate color pattern, the presence of dark spots on the posterior edge of scales of the longitudinal rows dorsal to the lateral line, the presence of a dark blotch on the caudal-fin base failing to reach the posterior tip of the middle caudal-fin rays; the dorsal region of the eyes red to orange in life; 5/3 longitudinal series of scales, above and below the lateral line, respectively; and the tips of the pectoral-fin rays not extending beyond the base of the pelvic fin. All specimens of M. cotinho have a completely pored literal line except for a few specimens from drainages in the Guyana. The redefinition of the taxonomic limits and geographic distribution of M. cotinho allowed us to reevaluate the taxonomic limits and geographic distribution of Hemigrammus newboldi, the identity of which has been previously questioned, but which is clearly diagnosed from M. cotinho based on the relatively longer pectoral fin, the presence of conical teeth in the posterior portion of the dentary, the absence of a reticulate color pattern of body and in the shorter longitudinal dark stripe on body. In addition, two new species of Moenkhausia are described: Moenkhausia rondoni sp n. from the rio Madeira basin, Brazil and Moenkhausia pirahan sp n. from the lower rio Madeira and rio Trombetas and rio Tapajós basins, Brazil.


Assuntos
Characidae , Caraciformes , Animais , Rios
8.
Ecotoxicol Environ Saf ; 205: 111314, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32956866

RESUMO

Brazilian freshwater ecosystems are continuously exposed to pesticides and domestic sewage. The Uruguay River was chosen for this study because of its international importance, as it flows through Brazil, Argentina, and Uruguay. It receives contaminants such as pesticides and domestic residues. Thus, the aim of this study to assess the accumulation of pesticides in muscle of the fish Astyanax jacuhiensis, its biochemical responses, and the presence of pesticides in water. In total, seven pesticides were registered in water from both river sites. Eight pesticides were detected in fish muscle. The biochemical responses showed that brain lipid peroxidation (LPO) and protein carbonyl (PC) in A. jacuhiensis were higher in the summer. Muscle showed the highest LPO levels in the spring and the highest PC in the summer. Liver LPO and PC levels were higher in the spring and summer. In the gills, the PC was higher in the spring and the LPO in the spring and winter. In the brain and in the gills, glutathione-S-transferase activity was high in the summer and autumn. Catalase activity was lower during the winter and spring. Non-protein thiol (NPSH) levels were lower in the brain in the winter and spring. Muscle tissue showed lower NPSH in the winter (site 1). Liver NPSH showed increased levels in liver in the spring and winter (site 2). The biochemical results clearly is related to pesticides and/or to the presence of other contaminants in the water such as metals or domestic sewage. The accumulation of pesticides in fish muscle added evidence that pesticides have been used in the area surrounding the Uruguay River. In conclusion, the biomarkers assayed in the present study could be used in future investigations considering other sampling sites along Uruguay River.


Assuntos
Characidae/fisiologia , Monitoramento Ambiental , Praguicidas/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Biomarcadores/metabolismo , Brasil , Characidae/metabolismo , Caraciformes/metabolismo , Caraciformes/fisiologia , Ecossistema , Brânquias/metabolismo , Peroxidação de Lipídeos , Metais/metabolismo , Praguicidas/análise , Rios/química , Estações do Ano , Poluentes Químicos da Água/análise
9.
Aquat Toxicol ; 226: 105567, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32745893

RESUMO

The increasing contamination of water bodies with mercury (Hg) raises concerns about the possible effects of this metal on native fish species. Our current understanding of its dynamics in fish organs remains limited. In this study, adult individuals of the native species Astyanax eigenmanniorum were exposed to three environmentally relevant HgCl2 concentrations (5, 100, and 170 µg L-1) for 96 h. To evaluate total Hg (THg) elimination, new individuals were exposed to 100 µg L-1 of HgCl2 (96 h), and at the end of the exposure period, half of the fish were placed in tanks with clean water for 168 h. In both assays, the organs were removed, and THg levels were measured using ICP-MS. The uptake of IHg in A. eigenmanniorum showed a differential accumulation in the organs. Gills, intestine, and brain were the tissues with the highest THg levels. Finally, no elimination of THg in the water was observed, but intestine and gills significantly removed the THg accumulated. Probably a Hg redistribution through the tissues could take place.


Assuntos
Characidae/metabolismo , Mercúrio/metabolismo , Poluentes Químicos da Água/metabolismo , Adulto , Animais , Bioacumulação , Encéfalo/metabolismo , Characidae/sangue , Monitoramento Ambiental , Brânquias/metabolismo , Humanos , Mucosa Intestinal/metabolismo , Mercúrio/análise , Mercúrio/toxicidade , Taxa de Depuração Metabólica , Distribuição Tecidual , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
10.
Sci Total Environ ; 736: 139644, 2020 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-32485386

RESUMO

In 2015, after the Fundão dam failure, in Minas Gerais State, Brazil, around 50 million cubic meters of sludge from iron mining tailings were discharged into the Doce River. After the dam collapse, surpassing concentrations of metals were observed in the river sediment, which could be harmful to aquatic organisms, including the fishes. The present study aimed to evaluate the toxic effects of both elutriate and water, collected from the Doce River, on Astyanax lacustris three years after the dam failure. A bioassay was carried out through subchronic exposure to Doce River water (E0) and three elutriate concentrations (10, 50 and 100%). Biochemical analyses (CAT, GST, AChE), metal bioaccumulation assays and calculation of the integrated biomarker response index, version 2 (IBRv2) were performed. The outcomes uncovered deleterious consequences on organisms exposed to E0, with AChE inhibition and bioaccumulation of Fe and Mn in both liver and gills. IBRv2 values were more elevated in fishes exposed to E0 for all tissues. Thus, the elutriate was not harmful for the assessed fishes, since complexing agents presented in the sediment, such as goethite and hematite, may have triggered metals' chelation. In this scenario, the elutriate may have acted as a protective agent for the subjected organisms, unlike the Doce River waters, in which contaminants were proven to be hazardous for the aquatic biota.


Assuntos
Characidae , Colapso Estrutural , Poluentes Químicos da Água/análise , Animais , Brasil , Monitoramento Ambiental , Rios , Água
11.
Zootaxa ; 4747(3): zootaxa.4747.3.10, 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32230104

RESUMO

A new species of Knodus is described from the rio Cupari drainage, a tributary from the right margin of the lower rio Tapajós, Pará State, Brazil. The new species differs from its congeners, except K. geryi, by having a dark basal blotch on each caudal fin lobe (vs. caudal fin lobes with sparse chromatophores, lacking basal blotches) and, with the exception of K. borki, K. heteresthes, and K. pasco, by having 10-12 scales around the caudal peduncle (vs. 13-15).


Assuntos
Characidae , Caraciformes , Animais , Brasil , Rios
12.
Zootaxa ; 4755(2): zootaxa.4755.2.10, 2020 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-32230188

RESUMO

A new species of Creagrutus is described from the Amazonian Piedmont, Colombia. The new species can be distinguished from congeners by presenting the following unique combination of characters: a dark mid-lateral stripe starting at anteriormost scale of lateral line, a vertically elongated humeral blotch, absence of dark blotches on dorsal fin and at base of middle caudal-fin rays, a triangular dentigerous surface of the premaxilla, 5-6 dentary teeth, and 11-12 predorsal scales. Comparisons with congeners distributed in the piedmont region of Río Caquetá basin are presented and its relationships among species of Creagrutus is inferred from the available phylogenetic framework.


Assuntos
Characidae , Caraciformes , Animais , Brasil , Colômbia , Filogenia , Rios
13.
Zootaxa ; 4751(3): zootaxa.4751.3.1, 2020 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-32230403

RESUMO

A taxonomic review of the Hyphessobrycon panamensis species-group is presented, with recognition of six valid species. In Central America, H. panamensis was restricted to the drainages of both Atlantic and Pacific coasts of Panama; H. savagei was recorded at the río Pírris and río Térraba, Pacific coast of Costa Rica, and Hyphessobrycon bussingi, new species, described from the río Sixaola basin, Atlantic coast of Costa Rica, and from the río Changuinola, río Guarumo and río San San, Atlantic coast of Panama. At trans-andean South America, H. columbianus was recorded at the río Acandí, Colombia, and its geographical distribution was extended into the coastal drainages in San Blas province, Panama; H. condotensis was recorded at the río Atrato, río Baudó, lower río Magdalena and río San Juan basins, Colombia, while H. sebastiani was considered as its junior synonym. Hyphessobrycon daguae was revalidated, erected to the specific level, considered as senior synonym of H. chocoensis, and recorded from the río Dagua, río Patía and río Telembí basins, in Colombia, the río Mira, at the border between Colombia and Ecuador, and the río Cayapas, río Mataje, and río Santiago, in Ecuador. Color pattern and secondary sexual characters (e.g. number, arrangement and shape of hooks in mature males) suggest that the Hyphessobrycon panamensis species-group is a putatively monophyletic lineage.


Assuntos
Characidae , Caraciformes , Animais , Brasil , Masculino , Rios
14.
Environ Pollut ; 262: 114252, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32126440

RESUMO

Given the toxicity of metals, including aluminum (Al), and the effects of water temperature on ectotherms, we investigated the individual or association effect of these variables (Al + acidic pH + temperature changes) on sperm quality of Astyanax altiparanae. Mature males were divided into nine experimental groups based on the combination of each of three water temperatures (20, 25, and 30 °C) with neutral and acidic pH values (7.0 and 5.5, respectively) with or without 0.5 mg L-1 Al. The fish were subjected to subacute, semi-static exposure and at 24 and 96 h were evaluated for seminal parameters: (1) pH; (2) osmolality; (3) sperm concentration; (4) sperm morphology; (5) sperm kinetics; and (6) sperm ultrastructure. At 30 °C, Al caused a reduction in osmolality (24 and 96 h) and sperm concentration (24 h). When analysing sperm kinetics (30 s post-activation), Al caused a reduction in total motility at all temperatures (24 h), and when this exposure time was longer (96 h), both acidic pH and Al addition to the water caused sperm motility reduction. By analysing curvilinear velocity (VCL) 30 s after sperm activation (24 and 96 h), the acidic pH caused a reduction in sperm movement at 20 and 30 °C, but at 25 °C Al triggered this reduction. Finally, Al in the water caused ultrastructural changes in the sperm head, midpiece, and flagella regardless of water temperature. Also, it was found that the combination of Al at 30 °C caused a reduction in sperm head area while at 20 °C, Al triggered a reduction in the midpiece area. Therefore, acidity influenced some A. altiparanae sperm parameters but Al in the water accentuated these effects on seminal quality, especially seminal osmolality and sperm concentration, kinetics, and ultrastructure. This toxicity was also influenced by changes in water temperature.


Assuntos
Characidae , Alumínio , Animais , Água Doce , Humanos , Concentração de Íons de Hidrogênio , Masculino , Motilidade Espermática , Espermatozoides , Temperatura , Água
15.
Bull Environ Contam Toxicol ; 104(5): 575-581, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32166333

RESUMO

Intensive agricultural and livestock activities demand high pesticide use and, consequently, contaminants reach aquatic ecosystems. In the lower Jacuí River, southern Brazil, there is a lack of knowledge about pesticide residues in water samples and the biochemical responses in native fish species. Thus, this study aimed to estimate the influence of pesticide residues and water parameters to biomarker responses in the native fish Astyanax spp. We performed seasonal biomonitoring in 2017 with water samples and fish collections. Biomarkers of oxidative stress, antioxidants, biotransformation, and neurotoxicity were analyzed in fish tissues. Fourteen pesticide residues were detected; they presented correlations with detoxification enzyme and oxidative stress biomarkers. These data indicate that most of variations can be related to the pesticide presence in water indicating high aquatic pollution in this place.


Assuntos
Characidae/metabolismo , Monitoramento Ambiental/métodos , Praguicidas/análise , Rios/química , Poluentes Químicos da Água/análise , Qualidade da Água/normas , Agricultura , Animais , Biomarcadores/metabolismo , Brasil , Ecossistema , Estresse Oxidativo/efeitos dos fármacos , Praguicidas/metabolismo , Poluentes Químicos da Água/metabolismo
16.
J Fish Biol ; 96(6): 1444-1453, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32166742

RESUMO

Hyphessobrycon chiribiquete n. sp. is described from the Río Caquetá drainage in Colombia and the Río Ucayali drainage in Peru, western Amazon. The new species is diagnosed from its congeners by having the following combination of characters: a conspicuous narrow midlateral stripe, starting on the sides of the body behind the opercle near the lateral line; lateral stripe overlapped anteriorly with a vertically elongated humeral blotch; inner premaxillary teeth pentacuspid; margin of anal fin falcate in mature males.


Assuntos
Characidae/anatomia & histologia , Characidae/classificação , Nadadeiras de Animais/anatomia & histologia , Animais , Colômbia , Masculino , Peru , Rios
17.
PLoS Comput Biol ; 16(3): e1007194, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32176680

RESUMO

Coordinated motion and collective decision-making in fish schools result from complex interactions by which individuals integrate information about the behavior of their neighbors. However, little is known about how individuals integrate this information to take decisions and control their motion. Here, we combine experiments with computational and robotic approaches to investigate the impact of different strategies for a fish to interact with its neighbors on collective swimming in groups of rummy-nose tetra (Hemigrammus rhodostomus). By means of a data-based agent model describing the interactions between pairs of H. rhodostomus (Calovi et al., 2018), we show that the simple addition of the pairwise interactions with two neighbors quantitatively reproduces the collective behavior observed in groups of five fish. Increasing the number of interacting neighbors does not significantly improve the simulation results. Remarkably, and even without confinement, we find that groups remain cohesive and polarized when each agent interacts with only one of its neighbors: the one that has the strongest contribution to the heading variation of the focal agent, dubbed as the "most influential neighbor". However, group cohesion is lost when each agent only interacts with its nearest neighbor. We then investigate by means of a robotic platform the collective motion in groups of five robots. Our platform combines the implementation of the fish behavioral model and a control system to deal with real-world physical constraints. A better agreement with experimental results for fish is obtained for groups of robots only interacting with their most influential neighbor, than for robots interacting with one or even two nearest neighbors. Finally, we discuss the biological and cognitive relevance of the notion of "most influential neighbors". Overall, our results suggest that fish have to acquire only a minimal amount of information about their environment to coordinate their movements when swimming in groups.


Assuntos
Comportamento Animal/fisiologia , Biologia Computacional/métodos , Tomada de Decisão Compartilhada , Animais , Characidae/metabolismo , Characidae/fisiologia , Peixes/metabolismo , Peixes/fisiologia , Relações Interpessoais , Modelos Biológicos , Movimento , Robótica , Comportamento Social , Software , Natação
18.
J Vis Exp ; (156)2020 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-32092048

RESUMO

Articles Discussed: Stahl, B. A. et al. Manipulation of Gene Function in Mexican Cavefish. Journal of Visualized Experiments. (146) (2019). Peuß, R. et al. Gamete Collection and In Vitro Fertilization of Astyanax mexicanus. Journal of Visualized Experiments. (147) (2019). Worsham, M. et al. Behavioral Tracking and Neuromast Imaging of Mexican Cavefish.Journal of Visualized Experiments. (147) (2019). Jaggard, J.B., Lloyd, E., Lopatto, A., Duboue, E.R., Keene, A.C. Automated Measurements of Sleep and Locomotor Activity in Mexican Cavefish. Journal of Visualized Experiments. (145) (2019). Luc, H., Sears, C., Raczka, A., Gross, J.B. Wholemount In Situ Hybridization for Astyanax Embryos. Journal of Visualized Experiments. (145) (2019). Riddle, M., Martineau, B., Peavey, M., Tabin, C. Raising the Mexican Tetra Astyanax mexicanus for Analysis of Post-larval Phenotypes and Whole-mount Immunohistochemistry. Journal of Visualized Experiments. (142) (2018).


Assuntos
Criação de Animais Domésticos , Characidae/fisiologia , Técnicas Genéticas , Animais
19.
Sci Total Environ ; 717: 137182, 2020 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-32065889

RESUMO

The eutrophication increases the quantity of algae that are deficient in highly unsaturated fatty acids (HUFA) n3, as EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), altering the bottom-up transfer of the entire food chain. Due to the importance of the fatty acids (FA) in physiological processes related to the main role of the membrane phospholipids (PL) and precursors of eicosanoids, and also the little knowledge about the influence of eutrophication in tropical ecosystems, it is important to understand how anthropogenic changes in the aquatic ecosystem affect the lipid quality, specifically n3 HUFAs. This study aimed to investigate the influence of eutrophication on the FA profile of the hepatic PL, as well as prostaglandin (PG) levels in Astyanax altiparanae females. Fish were collected in reservoirs with different eutrophication degrees: Jundiaí (Ju) reservoir and Embu-Guaçu (EG) branch, considered as mesotrophic points, and Barragem (Ba) and Aracati (Ar), branches from Guarapiranga reservoir, considered as supereutrophic and hypereutrophic points, respectively. The FA profile of the liver PL was analyzed by gas chromatography, and the concentration of liver PGE2 was analyzed using ELISA immunoassay kits. The degree of eutrophication did not alter the PG concentration and produced few modifications in the FA profile of hepatic PL. Fish collected at Ba and EG presented similar FA profiles, both with high percentages of n3 HUFA, especially DHA, in comparison to fish from Ju. However, no change was observed in the n3 HUFA profile of the fish from Ar. These data demonstrated that the FA profile in A. altiparanae seems to be more related to different physiological requirements of n3 HUFA of the species than eutrophication. So, this study contributed to findings on the trophic transfer dynamics in tropical freshwater reservoirs, where a direct effect of eutrophication on the availability of HUFA n3 to animals is not suggested.


Assuntos
Characidae , Animais , Eutrofização , Ácidos Graxos Insaturados , Feminino
20.
J Fish Biol ; 96(4): 950-955, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32048289

RESUMO

A new species of Brachychalcinus is described from the Rio Trombetas basin, Brazil. It differs from congeners by possessing a conspicuous rounded second humeral spot. Additionally, our new species differs from Brachychalcinus nummus, B. orbicularis and B. reisi by having a higher number of branched dorsal-fin rays, and from Brachychalcinus parnaibae by having a lower head depth.


Assuntos
Characidae/anatomia & histologia , Characidae/classificação , Nadadeiras de Animais/anatomia & histologia , Animais , Brasil , Cabeça/anatomia & histologia , Rios , Especificidade da Espécie
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