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1.
Ecotoxicol Environ Saf ; 188: 109907, 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31732269

RESUMO

The pollution from urban effluents discharged into natural waters is a major cause of aquatic biodiversity loss. Ecotoxicological testing contributes significantly to understand the risk of exposure to the biota and to establish conservation policies. The objective of the current study was to assess the toxicity of a river highly influenced by urban effluents (Atuba River, Curitiba city, Southern Brazil) to the early stages of development in four South American native fish species, investigating the consequences at the population level through mathematical modelling. The species chosen were Salminus brasiliensis, Prochilodus lineatus, Rhamdia quelen, and Pseudoplatystoma corruscans, ecologically important species encompassing different conservation statuses and vulnerability. The embryos were exposed from 8 to 96 h post fertilization to the Atuba River water, collected downstream of the largest wastewater treatment plant in the Metropolitan Region of Curitiba, and their survival rates and deformities were registered. The species S. brasiliensis and P. lineatus presented the highest mortality rates, showing high sensitivity to the pollutants present in the water. According to the individual-based mathematical model, these species showed high vulnerability and risk of extinction under the tested experimental conditions, even when different sensitivity scenarios of juveniles and adults were considered. The other two species, R. quelen and P. corruscans, showed a more resistant condition to mortality, but also presented high frequency and severity of deformities. These results emphasize the importance of testing the sensitivity of different Brazilian native species for the conservation of biodiversity and the application of models to predict the effects of pollutants at the population level.


Assuntos
Desenvolvimento Embrionário/efeitos dos fármacos , Peixes/crescimento & desenvolvimento , Águas Residuárias/toxicidade , Animais , Biota/efeitos dos fármacos , Brasil , Ecotoxicologia , Peixes/classificação , Dinâmica Populacional , Rios/química , Especificidade da Espécie
2.
An Acad Bras Cienc ; 91(4): e20181240, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31800702

RESUMO

This study presents the first record of Elops smithi for northern Brazil. The evidence suggests this species is being misidentified incorrectly as Elops saurus in estuaries of the Western Atlantic Ocean. Here, morphological, molecular, and cytogenetic evidence identified all ladyfish specimens from one estuary in the region as E. smithi. Thus, at least Elops smithi occurs in the northern coast of Brazil and it is recommended that specimens from this region identified as E. saurus be further investigated with genetic and cytogenetic tools in order to assure a correct species identification.


Assuntos
Peixes/classificação , Peixes/genética , Distribuição Animal , Animais , Brasil , Estuários , Filogenia , Reação em Cadeia da Polimerase , Análise de Sequência de DNA
3.
Nature ; 574(7776): 95-98, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31554969

RESUMO

Micronutrient deficiencies account for an estimated one million premature deaths annually, and for some nations can reduce gross domestic product1,2 by up to 11%, highlighting the need for food policies that focus on improving nutrition rather than simply increasing the volume of food produced3. People gain nutrients from a varied diet, although fish-which are a rich source of bioavailable micronutrients that are essential to human health4-are often overlooked. A lack of understanding of the nutrient composition of most fish5 and how nutrient yields vary among fisheries has hindered the policy shifts that are needed to effectively harness the potential of fisheries for food and nutrition security6. Here, using the concentration of 7 nutrients in more than 350 species of marine fish, we estimate how environmental and ecological traits predict nutrient content of marine finfish species. We use this predictive model to quantify the global spatial patterns of the concentrations of nutrients in marine fisheries and compare nutrient yields to the prevalence of micronutrient deficiencies in human populations. We find that species from tropical thermal regimes contain higher concentrations of calcium, iron and zinc; smaller species contain higher concentrations of calcium, iron and omega-3 fatty acids; and species from cold thermal regimes or those with a pelagic feeding pathway contain higher concentrations of omega-3 fatty acids. There is no relationship between nutrient concentrations and total fishery yield, highlighting that the nutrient quality of a fishery is determined by the species composition. For a number of countries in which nutrient intakes are inadequate, nutrients available in marine finfish catches exceed the dietary requirements for populations that live within 100 km of the coast, and a fraction of current landings could be particularly impactful for children under 5 years of age. Our analyses suggest that fish-based food strategies have the potential to substantially contribute to global food and nutrition security.


Assuntos
Pesqueiros , Peixes/metabolismo , Abastecimento de Alimentos , Internacionalidade , Micronutrientes/deficiência , Micronutrientes/metabolismo , Estado Nutricional , Animais , Teorema de Bayes , Cálcio/análise , Pré-Escolar , Proteínas na Dieta/análise , Ácidos Graxos Ômega-3/análise , Produtos Pesqueiros/análise , Produtos Pesqueiros/economia , Pesqueiros/economia , Peixes/classificação , Humanos , Lactente , Ferro/análise , Micronutrientes/análise , Selênio/análise , Vitamina A/análise , Zinco/análise
4.
Genes (Basel) ; 10(9)2019 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-31505864

RESUMO

The South American arowanas (Osteoglossiformes, Osteoglossidae, Osteoglossum) are emblematic species widely distributed in the Amazon and surrounding basins. Arowana species are under strong anthropogenic pressure as they are extensively exploited for ornamental and food purposes. Until now, limited genetic and cytogenetic information has been available, with only a few studies reporting to their genetic diversity and population structure. In the present study, cytogenetic and DArTseq-derived single nucleotide polymorphism (SNP) data were used to investigate the genetic diversity of the two Osteoglossum species, the silver arowana O. bicirrhosum, and the black arowana O. ferreirai. Both species differ in their 2n (with 2n = 54 and 56 for O. ferreirai and O. bicirrhosum, respectively) and in the composition and distribution of their repetitive DNA content, consistent with their taxonomic status as different species. Our genetic dataset was coupled with contemporary and paleogeographic niche modeling, to develop concurrent demographic models that were tested against each other with a deep learning approach in O. bicirrhosum. Our genetic results reveal that O. bicirrhosum colonized the Tocantins-Araguaia basin from the Amazon basin about one million years ago. In addition, we highlighted a higher genetic diversity of O. bicirrhosum in the Amazon populations in comparison to those from the Tocantins-Araguaia basin.


Assuntos
Peixes/genética , Especiação Genética , Filogenia , Polimorfismo de Nucleotídeo Único , Distribuição Animal , Animais , Biomassa , Peixes/classificação , Peixes/fisiologia , Filogeografia , América do Sul
5.
Parasitol Res ; 118(10): 2831-2841, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31473854

RESUMO

Corynosoma australe and C. cetaceum are the most frequently reported acanthocephalans in fish from the Argentine Sea, particularly in central and northern areas. Their definitive hosts are otariids and odontocete cetaceans, respectively. The low specificity of these larvae, in combination with high infective capability and long survival periods in fish, make them potentially good biological markers for stocks and other biological features of their fish hosts. In order to determine the distribution patterns of these species and their determining factors, a large dataset composed by newly collected fish samples, published and unpublished data from previous studies by the authors in the region were analysed in relation to host and environmental variables. The complete dataset comprised a total of 5084 fish, belonging to 29 species distributed in 21 families and 9 orders. Host size and trophic habits arose as the main determinants of abundance for both species of Corynosoma, showing higher abundances on larger fish and on higher trophic levels, as it is usual for trophically transmitted parasites. Biogeographic province and depth (indirectly representing the temperature of water) were the main drivers of the spatial distribution, displaying a latitudinal pattern associated to the temperature clines created by the interaction of Malvinas and Brazil currents, determining a decrease in abundance southwards and towards the deeper areas. No patterns were found regarding the distribution of definitive hosts. The knowledge of these distribution patterns of Corynosoma spp. in fish at regional scale, as well as of their causes, provides useful information to design management and conservation policies thus contributing to maintain the full and sustainable productivity of fisheries.


Assuntos
Acantocéfalos/isolamento & purificação , Doenças dos Peixes/parasitologia , Helmintíase Animal/parasitologia , Acantocéfalos/classificação , Acantocéfalos/genética , Acantocéfalos/crescimento & desenvolvimento , Animais , Oceano Atlântico , Brasil , Peixes/classificação , Peixes/parasitologia , Larva/classificação , Larva/genética , Larva/crescimento & desenvolvimento
6.
BMC Evol Biol ; 19(1): 168, 2019 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-31412761

RESUMO

BACKGROUND: Across the tree of life there are numerous evolutionary transitions between different habitats (i.e., aquatic and terrestrial or marine and freshwater). Many of these dramatic evolutionary shifts parallel developmental shifts that require physiological, anatomical and behavioral changes for survival and reproduction. Diadromy (scheduled movement between marine and freshwater) has been characterized as a behavior that acts as an evolutionary intermediate state between marine and freshwater environments, implying that diadromous lineages are evolutionarily transient. This hypothesis comes with assumptions regarding the rates of evolutionary transitions in and out of diadromy as well as rates of speciation and extinction in diadromous fishes. RESULTS: Based on a published phylogeny of 7822 species of ray-finned fishes, state speciation and extinction models of evolutionary transition between marine, freshwater, and diadromous species suggest transition rates out of diadromy are 5-100 times higher that transition between marine and freshwater or into diadromy. Additionally, high speciation and low extinction rates separate diadromous fishes from marine and freshwater species. As a result, net diversification (net diversification = speciation - extinction) is about 7-40 times higher in diadromous fishes compared to freshwater and marine respectively. Together the transition, speciation, and extinction rates suggest diadromy is the least stable of the three states. CONCLUSION: Evolutionary transitions to diadromy are rare in fishes. However, once established, diversification rates in diadromous lineages are high compared to both marine and freshwater species. Diadromous lineages tend to be more transient than marine or freshwater lineages and are found to give rise to marine and freshwater specialists in addition to diadromous descendants. Although diadromy is not a necessary evolutionary intermediate between marine and freshwater, these results support the interpretation of diadromy as an important, occasionally intermediate state, that contributes to biodiversity in fishes in all environments. This evolutionary instability of diadromous lineages is counteracted by their relatively high diversification rates. These findings highlight the importance of integrating the dynamics of diversification and major evolutionary transitions for understanding macroevolutionary patterns.


Assuntos
Migração Animal , Evolução Biológica , Ecossistema , Peixes/genética , Animais , Biodiversidade , Peixes/classificação , Peixes/fisiologia , Água Doce , Especiação Genética , Modelos Biológicos , Filogenia , Água do Mar
7.
Ying Yong Sheng Tai Xue Bao ; 30(8): 2829-2836, 2019 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-31418209

RESUMO

Based on the bottom trawl surveys in spring (May) and in autumn (September to October) from 2011 to 2017 (except 2012) in Haizhou Bay, variations in the mean trophic levels (MTL) and large fish index (LFI) of fish community were examined to understand the changes of fish community structure in Haizhou Bay. The results showed that the dominant fish species were Hexagrammos otakii, Enedrias fangi, Syngnathus acus, Pseudosciaena polyactis and Saurida elongata, which had obvious seasonal variation. The mean trophic level of fish community varied significantly among different years and seasons. Generally, MTL in autumn was higher than that in spring, and the variation of which in autumn always lagged behind that in spring. The result of LFI calculation showed that the large fish resources declined and fish community structure in Haizhou Bay showed an obvious tendency of miniaturization in recent years.


Assuntos
Baías , Peixes/fisiologia , Animais , China , Peixes/classificação , Perciformes , Estações do Ano
8.
Rev Bras Parasitol Vet ; 28(4): 625-631, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31460624

RESUMO

The current parasitological study was carried out to investigate helminth parasites infecting the Red spot emperor Lethrinus lentjan inhabiting Hurghada City at the Gulf of Suez, Red Sea, Egypt. Third-stage larvae of nematode parasite was isolated from the intestine as well as body cavity of the examined fish. Light and scanning electron microscopy revealed that this parasite belonged to Anisakidae family within the genus Pseudoterranova. The present species is named Pseudoterranova decipiens based on the presence of triangular mouth aperture with prominent boring teeth and soft swellings of the cuticle, long muscular esophagus, ventrally excretory pore, and narrow transverse slit of anal opening followed by a short mucron. The morphological characteristics of this species were confirmed by molecular analysis of 18S rDNA gene region of the present parasite. It demonstrated a close identity ≥89% with taxa under family Anisakidae, 85% with Raphidascarididae, and 79-84% with Toxocaridae. A preliminary genetic comparison between gene sequence of the present parasite and other oxyurid species placeed it as a putative sister taxon to other Pseudoterranova decipiens described previously. This study demonstrated that the 18S rDNA gene region of Pseudoterranova decipiens yielded a unique sequence that confirmed its taxonomic position in Anisakidae.


Assuntos
Doenças dos Peixes/parasitologia , Peixes/parasitologia , Nematoides/isolamento & purificação , Animais , DNA Ribossômico/genética , Egito , Peixes/classificação , Oceano Índico , Microscopia Eletrônica de Varredura , Nematoides/classificação , Nematoides/genética , Nematoides/ultraestrutura , Filogenia , RNA Ribossômico 18S/genética
9.
Genes (Basel) ; 10(8)2019 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-31426485

RESUMO

Circadian rhythms are biological rhythms with a period of approximately 24 h. While canonical circadian clock genes and their regulatory mechanisms appear highly conserved, the evolution of clock gene families is still unclear due to several rounds of whole genome duplication in vertebrates. The spotted gar (Lepisosteus oculatus), as a non-teleost ray-finned fish, represents a fish lineage that diverged before the teleost genome duplication (TGD), providing an outgroup for exploring the evolutionary mechanisms of circadian clocks after whole-genome duplication. In this study, we interrogated the spotted gar draft genome sequences and found that spotted gar contains 26 circadian clock genes from 11 families. Phylogenetic analysis showed that 9 of these 11 spotted gar circadian clock gene families have the same number of genes as humans, while the members of the nfil3 and cry families are different between spotted gar and humans. Using phylogenetic and syntenic analyses, we found that nfil3-1 is conserved in vertebrates, while nfil3-2 and nfil3-3 are maintained in spotted gar, teleost fish, amphibians, and reptiles, but not in mammals. Following the two-round vertebrate genome duplication (VGD), spotted gar retained cry1a, cry1b, and cry2, and cry3 is retained in spotted gar, teleost fish, turtles, and birds, but not in mammals. We hypothesize that duplication of core clock genes, such as (nfil3 and cry), likely facilitated diversification of circadian regulatory mechanisms in teleost fish. We also found that the transcription factor binding element (Ahr::Arnt) is retained only in one of the per1 or per2 duplicated paralogs derived from the TGD in the teleost fish, implicating possible subfuctionalization cases. Together, these findings help decipher the repertoires of the spotted gar's circadian system and shed light on how the vertebrate circadian clock systems have evolved.


Assuntos
Peptídeos e Proteínas de Sinalização do Ritmo Circadiano/genética , Evolução Molecular , Proteínas de Peixes/genética , Peixes/genética , Animais , Fatores de Transcrição de Zíper de Leucina Básica/genética , Sequência Conservada , Peixes/classificação , Duplicação Gênica , Filogenia
10.
Nat Commun ; 10(1): 3335, 2019 07 26.
Artigo em Inglês | MEDLINE | ID: mdl-31350395

RESUMO

In live-bearing animal lineages, the evolution of the placenta is predicted to create an arena for genomic conflict during pregnancy, drive patterns of male sexual selection, and increase the rate of speciation. Here we test these predictions of the viviparity driven conflict hypothesis (VDCH) in live-bearing poecilid fishes, a group showing multiple independent origins of placentation and extreme variation in male sexually selected traits. As predicted, male sexually selected traits are only gained in lineages that lack placentas; while there is little or no influence of male traits on the evolution of placentas. Both results are consistent with the mode of female provisioning governing the evolution of male attributes. Moreover, it is the presence of male sexually selected traits (pre-copulatory), rather than placentation (post-copulatory), that are associated with higher rates of speciation. These results highlight a causal interaction between female reproductive mode, male sexual selection and the rate of speciation, suggesting a role for conflict in shaping diverse aspects of organismal biology.


Assuntos
Evolução Biológica , Peixes/genética , Animais , Tamanho Corporal , Feminino , Peixes/classificação , Peixes/crescimento & desenvolvimento , Peixes/fisiologia , Masculino , Filogenia , Placenta/fisiologia , Placentação , Gravidez , Reprodução
11.
Anal Bioanal Chem ; 411(25): 6603-6614, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31317239

RESUMO

The topic of food analysis and safety has attracted increasing interest in recent decades owing to recent scandals concerning fraudulent activities (mislabeling, sophistication, adulteration, etc.) that can undermine human health. Among them, seafood fraud has probably the strongest relationship with food safety, an activity that goes beyond economic interests. This article explores the capabilities of an innovative instrumental setup, called the "iKnife," as a powerful tool in this specific research area, where until now genomics and proteomics have been the workhorses in analytical approaches. iKnife, which means "intelligent knife," is the name of a recent technology based on rapid evaporative ionization mass spectrometry (REIMS). REIMS is an emerging technique able to characterize different samples rapidly, affording a comprehensive profile usable as a fingerprint, without the need for preliminary extraction or cleanup procedures. In detail, a REIMS source is coupled to a high-resolution tandem mass spectrometer; such coupling allows one to maximize the amount of information (discriminant features) collected for a single analysis, as well as to focus on target analytes to achieve enhanced sensitivity and selectivity. A database was created from 18 marine species typical of the Mediterranean Sea, all caught in the very small area of the Strait of Messina, and reliable identification was achieved for each species with confidence higher than 99%. One big model and three submodels were built by principal component analysis and linear discriminant analysis for unambiguous key variable identification within each class (e.g., Cephalopoda), order (e.g., Perciformes), or family (e.g., Carangidae). Graphical abstract.


Assuntos
Peixes , Espectrometria de Massas/instrumentação , Alimentos Marinhos/análise , Animais , Análise Discriminante , Desenho de Equipamento , Peixes/classificação , Análise de Alimentos/instrumentação , Mar Mediterrâneo , Análise de Componente Principal , Alimentos Marinhos/classificação
12.
Artigo em Inglês | MEDLINE | ID: mdl-31318638

RESUMO

In this study, the levels of arsenic (As), cadmium (Cd) and lead (Pb) have been determined in the flesh of two species of fish, sardine (Sardina pilchardus) and swordfish (Xiphias gladius) fished in the Algerian coast. Quantification of As, Cd and Pb was carried out using an ICP-MS method and the results were compared with the thresholds set by national and international regulatory bodies. In a further step, the risk to consumers was assessed using estimated daily intake (EDI), target hazard quotient (THQ) and hazard index (HI).The average concentration of As and Pb was higher in sardine (1.82; 0.10 mg kg-1 w.w., respectively), than in swordfish (1.10 mg kg-1 w.w.; not determined), whereas the concentration recorded for Cd was the same for both species (0.01 mg kg-1 w.w.). These concentrations are below maximum limits set in regulations. The THQs and HI were widely below 1. The consumption of these fish does not pose risk to the consumers.


Assuntos
Arsênico/análise , Cádmio/análise , Monitoramento Ambiental , Peixes/metabolismo , Chumbo/análise , Poluentes Químicos da Água/química , Argélia , Animais , Peixes/classificação , Medição de Risco
13.
Int J Food Microbiol ; 305: 108256, 2019 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-31299548

RESUMO

Acanthocephalans of the genus Corynosoma are known as intestinal parasites, mainly of pinnipeds. Human corynosomiasis has been reported as an infrequent foodborne disease in Hokkaido, the northernmost island of Japan. Potential sources of the human infection are marine fish, because they are paratenic hosts of these parasites. In this study, the prevalence and intensity of larval Corynosoma in commercial fish from 17 fishing ports of Hokkaido were examined from April 2016 to January 2019. Out of a total of 1217 fish examined, 122 (10.0%) were infected with cystacanth larvae. The infected fish assemblage was composed of 7 families and 13 species from all the coastal seas of Hokkaido (the Pacific Ocean, Okhotsk Sea, and Japan Sea), showing that commercial fish can be source of human infection when eaten raw. Flatfish of the family Pleuronectidae showed the highest intensity of cystacanths, ranging from 1 to 56. A DNA barcoding system was developed in this study, based on the standard mitochondrial cox1 sequences of morphologically identified adults of Corynosoma spp. from pinnipeds in Hokkaido. By using the DNA barcoding, most of the fish-derived cystacanths were identified as either C. strumosum or C. villosum, and furthermore, a clinical isolate from human as C. villosum. Both of the species were commonly detected from various fish of Hokkaido, irrespective of the coastal seas. Flatfish frequently harbored C. villosum. Considering the wide range of commercial fish in Hokkaido and the advanced transportation system of fresh fish, there is a possibility that human corynosomiasis will occur everywhere in Japan.


Assuntos
Acantocéfalos/isolamento & purificação , Peixes/parasitologia , Acantocéfalos/classificação , Acantocéfalos/genética , Acantocéfalos/fisiologia , Animais , Código de Barras de DNA Taxonômico , Peixes/classificação , Helmintíase Animal , Ilhas , Japão , Larva/genética , Larva/fisiologia
14.
Korean J Parasitol ; 57(3): 273-281, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31284350

RESUMO

The infection status of digenetic trematode metacercariae (DTM) was investigated in fishes from 2 representative visiting sites of migratory birds in Gyeongsangnam-do, the Republic of Korea (Korea). A totaly 220 freshwater fishes (7 species) were collected from Junam-jeosuji (reservoir), and 127 fishes (7 species) were also collected from Woopo-neup (swamp) in June and October 2017. As the control group, total 312 fish (22 spp.) from Yangcheon in Sancheong-gun, Gyeongsangnam-do were also collected in June and October 2017. All fishes collected in 3 sites were examined with the artificial digestion method. In the fishes from Junam-jeosuji, more than 4 species, i.e., Clonorchis sinensis, Echinostoma spp., Diplostomum spp. and Cyathocotyle orientalis, of DTM were detected and their endemicy was very low, 0.70. More than 6 species, i.e., C. sinensis, Echinostoma spp., Metorchis orientalis, Clinostomum complanatum, Diplostomum spp. and C. orientalis, of DTM were found in the fishes from Woopo-neup, and their endemicy was low, 5.16. In the fishes from Yangcheon, more than 8 species, i.e., C. sinensis, Metagonimus spp., Centrocestus armatus, C. complanatum, C. orientalis, M. orientalis, Echinostoma spp., and Diplostomum spp., of DTM were detected, and their endemicity was relatively high, 95.48. The percentages of avian trematode metacercariae (ATM) were 99.6% and 94.7% in fishes from Junam-jeosuji and Woopo-neup whereas it was 74.1% in the control site, Yangcheon. The above findings suggested that migratory birds partly affect in endemicity of DTM in the fish in the 2 visiting sites in Gyeongsangnam-do, Korea.


Assuntos
Doenças das Aves/parasitologia , Doenças dos Peixes/parasitologia , Metacercárias/fisiologia , Trematódeos/fisiologia , Infecções por Trematódeos/veterinária , Migração Animal , Animais , Aves/parasitologia , Aves/fisiologia , Peixes/classificação , Peixes/parasitologia , Metacercárias/genética , Metacercárias/crescimento & desenvolvimento , Metacercárias/isolamento & purificação , República da Coreia , Trematódeos/genética , Trematódeos/crescimento & desenvolvimento , Trematódeos/isolamento & purificação , Infecções por Trematódeos/parasitologia
15.
J Fish Biol ; 95(4): 1145-1150, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31329266

RESUMO

Long-term survey time series repeated occurrence of the deep-sea chimaeroid species small-eyed rabbitfish Hydrolagus affinis and large-eyed rabbitfish H. mirabilis have been observed at same but few locations in Icelandic waters over 23 years. For H. affinis the catch at one specific station has consisted almost exclusively of mature males over the time period. Identification of potential aggregation locations is of vital importance to natural resource management because such aggregation may render these species vulnerable to potential fishing activities.


Assuntos
Peixes/classificação , Distribuição Animal , Animais , Peixes/fisiologia , Islândia , Masculino
16.
Int J Mol Sci ; 20(14)2019 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-31336568

RESUMO

Oplegnathus fasciatus and O. punctatus (Teleostei: Centrarchiformes: Oplegnathidae), are commercially important rocky reef fishes, endemic to East Asia. Both species present an X1X2Y sex chromosome system. Here, we investigated the evolutionary forces behind the origin and differentiation of these sex chromosomes, with the aim to elucidate whether they had a single or convergent origin. To achieve this, conventional and molecular cytogenetic protocols, involving the mapping of repetitive DNA markers, comparative genomic hybridization (CGH), and whole chromosome painting (WCP) were applied. Both species presented similar 2n, karyotype structure and hybridization patterns of repetitive DNA classes. 5S rDNA loci, besides being placed on the autosomal pair 22, resided in the terminal region of the long arms of both X1 chromosomes in females, and on the X1 and Y chromosomes in males. Furthermore, WCP experiments with a probe derived from the Y chromosome of O. fasciatus (OFAS-Y) entirely painted the X1 and X2 chromosomes in females and the X1, X2, and Y chromosomes in males of both species. CGH failed to reveal any sign of sequence differentiation on the Y chromosome in both species, thereby suggesting the shared early stage of neo-Y chromosome differentiation. Altogether, the present findings confirmed the origin of the X1X2Y sex chromosomes via Y-autosome centric fusion and strongly suggested their common origin.


Assuntos
Peixes/classificação , Peixes/genética , Cromossomos Sexuais , Animais , Mapeamento Cromossômico , Feminino , Marcadores Genéticos , Genoma , Heterocromatina/genética , Hibridização in Situ Fluorescente , Cariótipo , Masculino , Sequências Repetitivas de Ácido Nucleico
17.
J Fish Biol ; 95(4): 1125-1136, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31355448

RESUMO

In this study, the inverted trophic hypothesis was tested in the freshwater fish communities of a reservoir. The distribution of fish species in three freshwater habitats in the Jurumirim Reservoir, Brazil, was examined using both species richness and the relative proportions of different trophic groups. These groups were used as a proxy for functional structure in an attempt to test the ability of these measures to assess fish diversity. Assemblage structures were first described using non-metric multidimensional scaling (NMDS). The influence of environmental conditions for multiple fish assemblage response variables (richness, total abundance and abundance per trophic group) was tested using generalised linear mixed models (GLMM). The metric typically employed to describe diversity; that is, species richness, was not related to environmental conditions. However, absolute species abundance was relatively well explained with up to 54% of the variation in the observed data accounted for. Differences in the dominance of trophic groups were most apparent in response to the presence of introduced fish species: the iliophagous and piscivorous trophic groups were positively associated, while detritivores and herbivores were negatively associated, with the alien species. This suggests that monitoring functional diversity might be more valuable than species diversity for assessing effects of disturbances and managements policies on the fish community.


Assuntos
Biodiversidade , Peixes/fisiologia , Água Doce , Animais , Brasil , Peixes/classificação , Espécies Introduzidas
18.
Sci Total Environ ; 686: 26-37, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31174006

RESUMO

Changes in land-uses and cover are strong drivers of stream degradation worldwide. In Mediterranean ecoregions, land conversion from forest with native species to tree plantations, agricultural, and urban areas have drastically increased in recent years. Here, we examined the influence of land-use types on water quality (physical and chemical variables) and biota (benthic algae, macroinvertebrates, and fishes). We conducted field surveys between December-March 2016 (dry season) in 24 sites located across four land-use types including native vegetation (NV), tree plantation (TP), agriculture (Ag), and urban (Ur) within the Chilean Mediterranean ecoregion. We calculated metrics and multivariate statistics to assess correlations between biological and environmental variables. Significant differences between land-uses were found for environmental/physicochemical variables and the three biotic groups (i.e., benthic algae, macroinvertebrates, and fishes). We found higher chlorophyll-a biomass for TP, Ag, and Ur compared to NV streams. The macroinvertebrate diversity of sensitive taxa (i.e., Ephemeroptera, Plecoptera, and Trichoptera) and water quality were lower in land draining streams with human uses, other than NV, with the most evident impact found in Ag and Ur streams. NV and TP streams had a lower Diptera density and lower percentage of non-insect taxa. Fish richness and diversity were not affected by land-use. However, cold-water fishes (both native and introduced) were closely associated with NV and TP streams whereas warm-water fishes (mostly introduced) were closely associated with Ag and Ur streams. Multivariate analysis revealed that both local habitat and catchment-scale variables influenced each biological assemblage. Our findings suggest that benthic algae, macroinvertebrates, and fish populations are good indicators of human land-use disturbances, with Ag and Ur areas being the most detrimental for freshwater biota.


Assuntos
Ecossistema , Monitoramento Ambiental , Rios , Agricultura , Animais , Biodiversidade , Biota , Chile , Peixes/classificação , Humanos , Invertebrados/classificação , Microalgas , Poluição da Água/análise , Poluição da Água/estatística & dados numéricos , Qualidade da Água
19.
Theriogenology ; 135: 94-108, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31203093

RESUMO

Fish sperm quality assessment is helpful for optimizing production and for monitoring the environmental state. Sperm can be monitored relatively easy and, to date, various analyses have been applied and proven to be helpful in this task. Among them, sperm motility parameters such as sperm speed are one of the main performance traits during assisted fish reproduction. Apart from motility the sperm concentration, volume, and seminal plasma pH and osmolality are also frequently evaluated and are the main sperm quality indicators measured in fish sperm. However, other parameters also determine sperm fertilization potential. Recent knowledge reveals several additional parameters of high importance for sperm function. Among them are DNA integration, membrane stability, mitochondria status and enzymatic activity. Measuring all these parameters in fish sperm provides complex knowledge regarding male fertility and helps to improve broodstock maintenance protocols as well as gamete handling and fertilization processes. This review focuses on the presentation of the sperm quality measures for freshwater and marine species of the fish and provides information regarding recent methods of sperm quality evaluation.


Assuntos
Peixes/fisiologia , Análise do Sêmen/veterinária , Sêmen/fisiologia , Animais , Peixes/classificação , Processamento de Imagem Assistida por Computador , Masculino , Especificidade da Espécie
20.
An Acad Bras Cienc ; 91 Suppl 3: e20190260, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31166477

RESUMO

The Amazon basin houses a particular group of freshwater organisms, whose study tells the geological history of the region, how biological diversity was shaped, how it is maintained, and what it hides. The fish of the Amazon is represented by more than 3,000 known species distributed from the basal groups up to the more specialized ones. This species richness hides a diversity of adaptations that are dispersed at all levels of the biological organization. In this summary of the conference delivered at the Brazil-France Bilateral Symposium, held in Manaus in 2018, we describe two aspects of the hidden world of adaptive diversity: adaptations to changes in dissolved oxygen and the abilities of the Rio Negro fish to face acidic and ion-poor waters of their habitats. Also, we present the vulnerability of Amazonian fish to ongoing climate changes. Then, very briefly, we call attention to the many hidden biological processes that allow these fish species to survive their environments, much of which is unknown. Indeed, however, they are intricately related to men, either by responding to environmental disturbances that we have caused, or by containing information that contributes to improving the quality of the environment in which we live.


Assuntos
Adaptação Fisiológica/fisiologia , Biodiversidade , Ecossistema , Peixes/fisiologia , Oxigênio/fisiologia , Animais , Brasil , Mudança Climática , Peixes/classificação , Água Doce
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