Astyanax Jacuhiensis Research Articles

Combination of Water Quality Parameters and Bioassays for the Assessment of Two Rivers, Southern Brazil.

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.

Ecological impacts of pesticides on Astyanax jacuhiensis (Characiformes: Characidae) from the Uruguay river, Brazil

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.

Water quality monitoring of the Sinos River Basin, Southern Brazil, using physicochemical and microbiological analysis and biomarkers in laboratory-exposed fish

The aim of this study was to monitor the water quality of three rivers of the Sinos River Basin (SRB), southern Brazil. Five sites were selected to evaluate physicochemical and microbiological parameters and genotoxic and histopathological effects in the fish species Astyanax jacuhiensis. Eight water samples were collected from March 2012 to May 2013 at sites located in the upper, middle and lower sections of the SRB. After collection, 35 water quality parameters were analyzed and fish were exposed to water samples under laboratory conditions. Five-day biochemical oxygen demand (BOD5), thermotolerant coliforms, ammoniacal nitrogen, dissolved oxygen, aluminum, iron and manganese values exceeded the permissible limits in some samples of the three sections and the cluster analysis showed three distinct groups composed by sites located in the same section of SRB. The micronuclei (MN) and other nuclear abnormalities (NA) frequencies did not differ from the control group in any sample. Higher frequencies of lamellae with alterations, such as hypertrophy and hyperplasia of epithelial cells, epithelial lifting, aneurysm, edema and necrosis were observed in fish exposed to some water samples of the five sites. The most frequent histopathological alteration was hypertrophy of epithelial cells. Therefore, in this study, the analysis of gill histopathological alterations showed higher sensitivity than the MN test under the conditions studied. The physicochemical and microbiological parameters and histopathological analysis indicate deterioration of water quality at sites located in the three sections of the Sinos River Basin.

Morphologically Cryptic Species of the Astyanax bimaculatus "Caudal Peduncle Spot" Subgroup Diagnosed Through Cytogenetic Characters.

Astyanax is a species-rich polyphyletic genus distributed between the southern United States and central Argentina. The genus contains groups of cryptic species, which are difficult to distinguish, and are sometimes identified wrongly. Basic and molecular cytogenetic analyses were run on Astyanax abramis and three junior synonyms of Astyanax lacustris: Astyanax altiparanae, from the upper Paraná River basin, Astyanax asuncionensis, from the lower Paraná basin, and Astyanax jacuhiensis, from the upper Uruguay River. These species all belong to the Astyanax bimaculatus group. All species presented 2n = 50 chromosomes and single nucleolar organizing regions (NORs). In A. altiparanae, the karyotype was 6m + 28sm+4st+12a and the NORs were present in pair 20, while A. jacuhiensis was 8m + 28sm+6st+8a, with NORs in pair 22, and A. asuncionensis was 8m + 24sm+6st+12a, with NORs in pair 20. A. abramis was 4m + 30sm+8st+8a with NORs in pair 22. Fluorescence in situ hybridization revealed single 5S rDNA cistrons in A. altiparanae and A. asuncionensis, and multiple (4) cistrons in A. abramis and A. jacuhiensis. Heterochromatin had a distinct distribution in each species, but was predominantly centromeric and interstitial proximal. In A. abramis and A. asuncionensis, the first acrocentric chromosome pair presented centromeric, telomeric, and interstitial-proximal heterochromatin in the long arm, which may represent the presence of homologous chromosomes in these species. While there are some cytogenetic similarities, differences in the location of 5S rDNA, distribution of heterochromatin, and karyotype formulae contribute to the differentiation of the study species, and support the identification of phylogenetically proximate groups in the "Astyanax clade."

Biochemical Responses in Freshwater Fish Exposed to Insecticide Propoxur.

Although designed to control pests selectively, there is some evidence that environmental contamination by pesticides increases risks for humans and wildlife. In the present study, we evaluated biomarkers of oxidative stress in Astyanax jacuhiensis exposed to (5, 15 and 30µg L-1) of carbamate Propoxur (PPX) for 96h. Glutathione S-transferase (GST) in liver and gills showed reduced activity in all PPX concentrations tested. Acetylcholinesterase (AChE) activities reduced in brain and muscle at concentrations 15 and 30µg L-1 of PPX. Lipid peroxidation (LPO) and hydrogen peroxide (HP) had no significant differences. In the brain, protein carbonyl (PC) increased in all groups treated with PPX. Although PPX is a selective pesticide, it causes oxidative damage and enzyme alteration in fish. This study pointed out some biomarkers that could be used to assess effects of environmentally relevant concentrations of pesticides, and infer about studies using fish as bioindicator.

A new species of Characithecium (Monogenea: Dactylogyridae) from external surface and gills of two species of Astyanax (Ostariophysi: Characidae) in southern Brazil

A new species of Characithecium, a genus of monogenean parasites of Neotropical characids, is described from specimens collected on the body surface and gills of Astyanax aff. fasciatus and Astyanax jacuhiensis from Lake Guaíba, State of Rio Grande do Sul, Brazil. The new species is similar to Characithecium costaricensis, but differs by having the haptor separated from the body by a long peduncle, and by having an accessory piece composed of 2 subunits in the male copulatory complex – 1 ventral pincer-shaped at the distal end, and 1 dorsal with an expanded rod-shaped proximal end and the distal end containing 3 elongated projections–, and the dorsal bar usually presenting a small median elevation in the anterior margin. This study increases the number of species of Characitecium to 7 and expands our knowledge on the diversity of monogenean parasites of characids.

Gill histopathology and micronucleus test of Astyanax jacuhiensis (Cope, 1894) (Teleostei, Characidae) to evaluate effects caused by acute exposure to aluminum

http://dx.doi.org/10.5007/2175-7925.2016v29n1p75A contaminação de ecossistemas aquáticos por alumínio (Al) é geralmente ocasionada por várias atividades antropogênicas. Diversas alterações morfológicas, fisiológicas e bioquímicas observadas em organismos aquáticos podem ser atribuídas à exposição ao Al. Neste contexto, o objetivo desse estudo foi investigar os efeitos da exposição aguda de peixes da espécie Astyanax jacuhiensis a diferentes concentrações de Al através da histologia de brânquias e frequência de micronúcleos (MN) e anormalidades nucleares (AN) em eritrócitos. Os animais foram expostos às concentrações subletais de 0.3 mg/L e 30 mg/L de alumínio em pH neutro por 72 h. Um grupo controle foi mantido em água filtrada. As alterações branquiais foram caracterizadas por hiperplasia e hipertrofia de células epiteliais, fusão lamelar, edema, descolamento epitelial, aneurisma e necrose. Um aumento significativo (p<0.05) foi observado na frequência de lamelas alteradas nos grupos expostos às duas concentrações de Al em comparação aos animais controle. No entanto, não foram observadas diferenças significativas nas frequências de MN e AN. Embora não tenham sido encontradas evidências de genotoxicidade, os resultados encontrados na análise morfológica sugerem que o Al foi tóxico para os peixes nas duas concentrações testadas em pH neutro.

Review of species of the Astyanax bimaculatus "caudal peduncle spot" subgroup sensu Garutti & Langeani (Characiformes, Characidae) from the rio La Plata and rio São Francisco drainages and coastal systems of southern Brazil and Uruguay.

The species of the Astyanax bimaculatus 'caudal peduncle spot' subgroup of the drainages of the rios La Plata and São Francisco, as well as southeastern coastal systems of Brazil and Uruguay, are revised. Two nominal species are considered valid and are redescribed: Astyanax lacustris and A. abramis. Astyanax jacuhiensis, A. asuncionensis and A. altiparanae are recognized as new junior synonyms of A. lacustris. Bertoniolus paraguayensisis recognized as a new junior synonym of A. abramis. The names Astyanax orbignyanus, A. vittatus, and A. borealis are considered species inquirendae. Notes on A. maculisquamis, included in the 'caudal peduncle spot' subgroup from rio Guaporé (rio Madeira drainage), and Astyanax bahiensis from Bahia, mistakenly considered of the same subgroup, are presented.

Water quality assessment of the Sinos River - RS, Brazil.

Worldwide environmental pollution is increasing at the same rate as social and economic development. This growth, however, is disorganized and leads to increased degradation of water resources. Water, which was once considered inexhaustible, has become the focus of environmental concerns because it is essential for life and for many production processes. This article describes monitoring of the water quality at three points along the Sinos River (RS, Brazil), one in each of the upper, middle and lower stretches. The points were sampled in 2013 and again in 2014. The water samples were analyzed to determine the following physical and chemical parameters plus genotoxicity to fish: metals (Cr, Fe, Al), chemical oxygen demand, biochemical oxygen demand, chlorides, conductivity, total suspended solids, total phosphorous, total and fecal coliforms, pH, dissolved oxygen, turbidity, total Kjeldahl nitrogen nitrate and ammoniacal nitrogen. Genotoxicity was tested by exposing individuals of the species Astyanax jacuhiensis to water samples and then comparing them with a control group exposed to water from the public water supply. The results confirmed the presence of substances with genotoxic potential at the sample points located in the middle and lower stretches of the river. The results for samples from the upper stretch, at P1, did not exhibit differences in relation to the control group. The physical and chemical analyses did not detect reductions in water quality in the lower stretch, as had been expected in view of the large volumes of domestic and industrial effluents discharged into this part of the river.

Spatial and temporal biomarkers responses of Astyanax jacuhiensis (Cope, 1894)(Characiformes: Characidae) from the middle rio Uruguai, Brazil

Due to intense agricultural activity in the rio Uruguai (South Brazil), there is the potential for aquatic contamination by agrochemicals. In this region, there are many reservoirs to meet the water demand for rice fields, forming lentic environments. In line with this information, the aim of this study was to show a comparative analysis of some biomarkers, such as lipid peroxidation (TBARS), gluthatione S-transferase (GST), non-protein thiols (NPSH), amino acids (AA) and piscine micronucleus tests (MNE) in Astyanax jacuhiensis from lentic and lotic environments in the middle rio Uruguai region, comparing warm and cold seasons. Eight pesticides were found in water samples, with propoxur having the highest concentration found in both environments and seasons. Fish from the warm season showed higher levels of biochemical biomarkers, and fish from the cold season showed higher levels of MNE and AA. TBARS and AA presented higher levels in fish from the river, while GST, NPSH, MNE and AA presented higher levels in fish from dams. These environments have different characteristics in terms of redox potential, aeration, sedimentation, trophic structure, agrochemicals input and others, which may affect the physiological and biochemical responses of fish in against adverse situations.

Supplemental observations on the morphology of Procamallanus (Spirocamallanus) hilarii (Nematoda: Camallanidae) parasitizing two species of Astyanax (Characiformes: Characidae) and ecological analyses

Procamallanus (Spirocamallanus) hilarii parasitizes several fish species but only few studies on morphology and ecology have been published. In this study we describe the morphology of P. (S.) hilarii parasitizing Astyanax aff. fasciatus and Astyanax jacuhiensis, and compare ecological parameters of their populations. Seventy A. aff. fasciatus and 60 A. jacuhiensis individuals were captured in Lake Guaiba, Rio Grande do Sul State, Brazil, between March 2012 and December 2013. The specimens of P. (S.) hilarii presented an oval oral opening with 6 cuticular elevations and 2 groups of papillae (one internal and one external) in the anterior region of the body. Males have 8 pairs of sessile caudal papillae (4 pre-cloacal and 4 post-cloacal), spicules with distal bifurcation and lack caudal alae. The prevalence of P. (S.) hilarii was higher in A. aff. fasciatus (69%) than in A. jacuhiensis (18%), whereas there was no difference in mean intensity (respectively, 2 and 5) and mean abundance (respectively, 1.6 and 0.9) of infection between the 2 host species. We suggest that the consumption of copepods, intermediate hosts of P. (S.) hilarii, may explain this difference.

Evaluation of genotoxicity and cytotoxicity of water samples from the Sinos River Basin, southern Brazil.

Some water bodies in the Sinos River Basin (SRB) have been suffering the effects of pollution by residential, industrial and agroindustrial wastewater. The presence of cytotoxic and genotoxic compounds could compromise the water quality and the balance of these ecosystems. In this context, the research aimed to evaluate the genotoxicity and cytotoxicity of the water at four sites along the SRB (in the cities of Santo Antônio da Patrulha, Parobé, Campo Bom and Esteio), using bioassays in fish and cell culture. Samples of surface water were collected and evaluated in vitro using the Astyanax jacuhiensis fish species (micronucleus test and comet assay) and the Vero lineage of cells (comet assay and cytotoxicity tests, neutral red - NR and tetrazolium MTT). The micronucleus test in fish showed no significant differences between the sampling sites, and neither did the comet assay and the MTT and NR tests in Vero cells. The comet assay showed an increase in genetic damage in the fish exposed to water samples collected in the middle and lower sections of the basin (Parobé, Campo Bom and Esteio) when compared to the upper section of the basin (Santo Antônio da Patrulha). The results indicate contamination by genotoxic substances starting in the middle section of the SRB.

A new species of Cacatuocotyle (Monogenea, Dactylogyridae) parasitizing two species of Astyanax (Ostariophysi, Characidae) in southern Brazil.

A new species of Cacatuocotyle is described from the external surface of Astyanax aff. fasciatus and Astyanax jacuhiensis from Lake Guaíba, State of Rio Grande do Sul, Brazil. It differs from the other three species of the genus, recorded from Mexico and the State of Paraná, Brazil, by possessing an accessory piece with a long proximal portion, a U-shaped bar with irregular posterior margin in its midportion, and a haptor containing two circular thickenings with muscular anterior margins. Only one monogenean species, Urocleidoides astyanacis (= Characithecium costaricensis) was recorded for the host Astyanax aff. fasciatus, whereas none were known for A. jacuhiensis. This paper records a new host (A. jacuhiensis) for monogeneans in southern Brazil and extends southward with the geographical distribution of the genus Cacatuocotyle to the State of Rio Grande do Sul, Brazil.

Chromosome Studies of Astyanax jacuhiensis Cope, 1894 (Characidae) from the Tramandai River Basin, Brazil, Using in situ Hybridization with the 18S rDNA Probe, DAPI and CMA3 Staining

The genus Astyanax comprises 86 species of fish distributed in Brazilian river basins and is considered of the Incertae sedis group within the family Characidae. This study presents an analysis of 12 specimens of Astyanax jacuhiensis from the Tramandai River Basin, RS Brazil: 6 from the Maquiné River and 6 from the Quadros Lagoon. All specimens showed a diploid number equal to 50 chromosomes with different karyotypic formula between the two localities. The population from the Maquiné River showed 10m+26sm+6st+8a (FN=92). Fish from the Quadros Lagoon showed 12m+20sm+6st+12a (FN=88). AgNORs were evidenced in the short arm of one acrocentric chromosome pair in both populations, confirmed by FISH with the 18S rDNA probe. CMA3 fluorochrome corresponded with the AgNOR sites, while DAPI staining was negative in these regions. C banding revealed that heterochromatin was weakly distributed, mainly in the pericentromeric and terminal regions in most chromosomes. Analyses of male gonadal tissue were conducted with the objective of characterizing the meiotic chromosome behavior in A. jacuhiensis. The following stages were evidenced: spermatogonial with 50 chromosomes, pachytene and metaphase I with 25 bivalents, and metaphase II with 25 chromosomes, thus confirming the diploid number of the species. Chromosomal abnormalities were not observed. This study shows preliminary data on A. jacuhiensis from the Tramandai River Basin, contributing with more chromosomal information for this group of fish.

Can weight/length relationship predict size at first maturity? A case study with two species of Characidae

A weight/length relationship was established for Astyanax jacuhiensis (Cope, 1894) (n = 370) and Cheirodon ibicuhiensis Eigenmann, 1915 (n = 701), from samples taken monthly in Fortaleza Lagoon, Cidreira, Rio Grande do Sul, from December 1991 through November 1992. Both species showed a polyphasic allometric growth pattern, each stanza described by an independent power equation controlled by a switch function. For C. ibicuhiensis, this change in the growth pattern occurred at 2.948 cm standard length (SL), close to published sizes for the attainment of female maturity. The change in the growth pattern of A. jacuhiensis (SL = 3.481 cm) was below the predicted size at first maturity, and merits further investigation. Although not conclusive, our data suggest that a complex growth pattern is frequent in nature, and perhaps is not usually identified because trends are obscured by natural variability. Despite the increased complexity resulting from the application of a more-complex equation, the identification of a change in the growth pattern could indicate important aspects of fish biology, including the attainment of sexual maturity.

Cytogenetic data on Astyanax jacuhiensis (Characidae) in the lago Guaíba and tributaries, Brazil

Cytogenetic analyses were performed in Astyanax jacuhiensis from lago Guaíba, Brazil. The diploid number was 50, with a karyotype composed of 8m+30sm+4st+8a chromosomes, FN = 92. The AgNORs were observed in 2 to 5 chromosomes, with intra- and interindividual variation. The sm pair 8 observed always carried NORs on the short arms, presenting size heteromorphism between homologous. Fluorescence in situ hybridization (FISH) with an 18S rDNA probe only confirmed the location of ribosomal cistrons in the sm pair 8, and heteromorphism of these regions between the homologous chromosomes. C-banding revealed the occurrence of weak C-positive heterochromatin in the pericentromeric regions of several chromosomes, in addition to more evident bands interstitially located on some chromosome pairs and in the terminal region of the short arms in pair 8. C-banding plus CMA3 revealed light fluorescent signals in different chromosomes of the karyotype, with a strong terminal site in pair 8, indicating the occurrence of several GC-rich heterochromatic regions in this species. Our results provide the first description of the Astyanax jacuhiensis karyotype, showing karyotype similarities when compared to various populations of A. altiparanae and A. bimaculatus, indicating that chromosomal features are very similar for these three species.

Biomonitoring of genotoxicity using micronuclei assay in native population of Astyanax jacuhiensis (Characiformes: Characidae) at sites under petrochemical influence

Bom Jardim brook is a small stream that flows through an area under the influence of a Petrochemical Complex, demanding control over its quality, so a genotoxic evaluation was performed. This study was conducted in situ, based on previous analysis on the same subject. These were performed both in vitro, with Salmonella typhimurium and human lymphocytes, and in vivo, using bioassays with fish exposed to water from the study area. The purpose of this research was to assess the quality of the aquatic environment and possible effects from petrochemical pollution to surrounding native populations. Micronuclei (MNE) and nuclear abnormalities (NA) frequencies in peripheral blood of Astyanax jacuhiensis, a native fish species collected from the study area, were used as biomarkers. Study period was from summer/99 to spring/2001, using samples obtained seasonally at two ponds upstream from the industrial area (BJN and BJPa) and two sites in Bom Jardim brook (BJ002 and BJ000), which are subject to Complex influence. MNE and NA frequencies found in individuals from BJ002 and BJ000 were similar, showing positive genotoxic responses related to control sites BJN and BJPa. No differential sensitivity could be verified for micronuclei induction between genders of A. jacuhiensis in the studied population. This study showed that sites subject to petrochemical influence were under higher genotoxic impact. Biomarkers adequacy to the case and the sensitivity of A. jacuhiensis for water monitoring could be also inferred.