RESUMO
The golden mussel (Limnoperna fortunei) is an aggressive invasive species in South America, where it endangers native species and freshwater ecosystems, in addition to causing extensive economic losses, mainly to the hydroelectric sector. Currently, there's no efficient control method available and the invasion has progressed across the continent. Its high reproduction rate is one of the key factors of the golden mussel's high invasive potential and, recently, efforts have been done in order to understand the reproduction and the sexual features of this species. However, its cytogenetics characterization is incipient and the possible occurrence of sex-specific cytogenetic features was never investigated. In this study, we aimed to characterize the chromosomal morphometry, the distribution profile of heterochromatin, and to detect possible sex-related epigenetic marks in the golden mussel. Results revealed that the karyotypic structure is similar in both sexes and no chromosome heteromorphism was observed between males and females specimens. The data increment the cytogenetic characterization of Limnoperna fortunei and contribute for future studies that aim to further investigate its reproduction and underlying sex determination processes.
Assuntos
Ecossistema , Mytilidae , Feminino , Masculino , Animais , Mytilidae/genética , Citogenética , Cromossomos Sexuais/genética , CariotipagemRESUMO
BACKGROUND: The golden mussel (Limnoperna fortunei) is a highly invasive species that causes environmental and socioeconomic losses in invaded areas. Reference genomes have proven to be a valuable resource for studying the biology of invasive species. While the current golden mussel genome has been useful for identifying new genes, its high fragmentation hinders some applications. FINDINGS: In this study, we provide the first chromosome-level reference genome for the golden mussel. The genome was built using PacBio HiFi, 10X, and Hi-C sequencing data. The final assembly contains 99.4% of its total length assembled to the 15 chromosomes of the species and a scaffold N50 of 97.05 Mb. A total of 34,862 protein-coding genes were predicted, of which 84.7% were functionally annotated. A significant (6.48%) proportion of the genome was found to be in a hemizygous state. Using the new genome, we have performed a genome-wide characterization of the Doublesex and Mab-3 related transcription factor gene family, which has been proposed as a target for population control strategies in other species. CONCLUSIONS: From the applied research perspective, a higher-quality genome will support genome editing with the aim of developing biotechnology-based solutions to control invasion. From the basic research perspective, the new genome is a high-quality reference for molecular evolutionary studies of Mytilida and other Lophotrochozoa, and it may be used as a reference for future resequencing studies to assess genomic variation among different golden mussel populations, unveiling potential routes of dispersion and helping to establish better control policies.
Assuntos
Mytilidae , Animais , Mytilidae/genética , Genoma , Cromossomos/genéticaRESUMO
Nile tilapia (Oreochromis niloticus) is a freshwater phytoplanktivorous fish species reported to accumulate and tolerate large amounts of cyanotoxins such as microcystins (MCs). The present study aimed to investigate molecular responses to the acute exposure of Nile tilapia to the Microcystin-LA analogue (MC-LA). Thus, the specimens were sublethally exposed to 1000⯵gâ¯kg-1 of MC-LA for 12, 24, 48, and 96â¯h. Gene expression of PP1, PP2A, GST, GPX and actin was analyzed by quantitative PCR. The protein abundance profile of PP2A was determined by immunoblotting, while the integrity of its biological function was assessed by a phosphatase enzymatic assay. PP2A activity was significantly and strongly reduced by MC-LA. A resulting feedback mechanism significantly increased PP2A gene expression and protein abundance in all assessed times. However, a recovery of that phosphatase activity was not observed. In this study, the observed increase in GPX gene expression was the only response that could be directly related to the unknown factors associated to the fish survival to such high dose exposure.
Assuntos
Ciclídeos/metabolismo , Microcistinas/toxicidade , Actinas/genética , Actinas/metabolismo , Animais , Ciclídeos/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Glutationa Peroxidase/genética , Glutationa Peroxidase/metabolismo , Glutationa Transferase/genética , Glutationa Transferase/metabolismo , Injeções Intraperitoneais , Proteína Fosfatase 1/genética , Proteína Fosfatase 1/metabolismo , Proteína Fosfatase 2/genética , Proteína Fosfatase 2/metabolismoRESUMO
OBJECTIVE: To investigate the biocatalytic potential of Colletotrichum acutatum and Colletotrichum nymphaeae for monoterpene biotransformation. RESULTS: C. acutatum and C. nymphaeae used limonene, α-pinene, ß-pinene, farnesene, citronellol, linalool, geraniol, perillyl alcohol, and carveol as sole carbon and energy sources. Both species biotransformed limonene and linalool, accumulating limonene-1,2-diol and linalool oxides, respectively. α-Pinene was only biotransformed by C. nymphaeae producing campholenic aldehyde, pinanone and verbenone. The biotransformation of limonene by C. nymphaeae yielded 3.34-4.01 g limonene-1,2-diol l-1, depending on the substrate (R-(+)-limonene, S-(-)-limonene or citrus terpene (an agro-industrial by-product). This is among the highest concentrations already reported for this product. CONCLUSIONS: This is the first report on the biotransformation of these terpenes by Colletotrichum spp. and the biotransformation of limonene to limonene-1,2-diol possibly involves enzymes similar to those found in Grosmannia clavigera.
Assuntos
Biotransformação/fisiologia , Colletotrichum/metabolismo , Monoterpenos/metabolismo , Monoterpenos Acíclicos , Carbono/metabolismo , Biologia Computacional , Cicloexenos , Limoneno , Monoterpenos/análise , Monoterpenos/química , Óleos de Plantas , TerpenosRESUMO
Background: For more than 25 years, the golden mussel, Limnoperna fortunei, has aggressively invaded South American freshwaters, having travelled more than 5000 km upstream across 5 countries. Along the way, the golden mussel has outcompeted native species and economically harmed aquaculture, hydroelectric powers, and ship transit. We have sequenced the complete genome of the golden mussel to understand the molecular basis of its invasiveness and search for ways to control it. Findings: We assembled the 1.6-Gb genome into 20 548 scaffolds with an N50 length of 312 Kb using a hybrid and hierarchical assembly strategy from short and long DNA reads and transcriptomes. A total of 60 717 coding genes were inferred from a customized transcriptome-trained AUGUSTUS run. We also compared predicted protein sets with those of complete molluscan genomes, revealing an exacerbation of protein-binding domains in L. fortunei. Conclusions: We built one of the best bivalve genome assemblies available using a cost-effective approach using Illumina paired-end, mate-paired, and PacBio long reads. We expect that the continuous and careful annotation of L. fortunei's genome will contribute to the investigation of bivalve genetics, evolution, and invasiveness, as well as to the development of biotechnological tools for aquatic pest control.
Assuntos
Mapeamento de Sequências Contíguas/métodos , Genoma , Espécies Introduzidas , Mytilidae/genética , Proteínas/genética , Transcriptoma , Animais , Brasil , Ontologia Genética , Sequenciamento de Nucleotídeos em Larga Escala , Anotação de Sequência Molecular , Mytilidae/classificação , Fases de Leitura Aberta , Controle de Pragas , Filogenia , Domínios e Motivos de Interação entre Proteínas , Proteínas/metabolismoRESUMO
The complete sequence of the brown mussel Perna perna mitochondrial genome is described in this article. It was sequenced in 1/11 of an Illumina HiSeq lane using Nextera multiplexing kit. The mitogenome was assembled using both (i) de novo assembly and (ii) referenced-based strategies with mitoMaker software. Perna perna mitogenome is a circular molecule of 18,415 bp in size, containing 12 protein-coding genes, 23 transfer RNAs, 2 ribossomal RNAs and several non-coding regions. As shown in the previous studies, Perna perna does not present the doubly uniparental inheritance system (DUI) of mitochondria and does not encode the ATPase8 gene, in accordance with other Mytilidae data.
Assuntos
Genes Mitocondriais , Genoma Mitocondrial , Perna (Organismo)/genética , Animais , Evolução Molecular , Ordem dos Genes , Sequenciamento de Nucleotídeos em Larga Escala , Análise de Sequência de DNARESUMO
Despite being considered friendlier to the environment, biodiesel fuel can be harmful to aquatic organisms, especially when combined with petroleum diesel fuel. In this work we evaluated the effects of mineral diesel fuel containing increasing concentrations of biodiesel (5% and 20%, namely B5 and B20) and pure biodiesel (B100), at concentrations of 0.001 and 0.01mLL(-1), after 15 days of exposure, in armored catfish (Pterygoplichtys anisitsi). Toxicity tests were also performed to estimate LC50 values (96h) for each compound. Biotransformation enzymes [ethoxyresorufin-O-deethylase (EROD), and glutathione S-transferase (GST)] as well as oxidative stress markers (superoxide dismutase, SOD, catalase, CAT, glutathione peroxidase, GPx, and the level of lipid peroxidation) were measured in liver and gills after treatment. Genotoxic effects were also accessed in erythrocytes using the comet assay and by evaluating the frequency of micronuclei formation. Further, the mRNA of cytochrome P450 1A (CYP1A) was also measured in liver. Mortality was not observed even exposure to concentrations as high as 6.0mLL(-1). EROD and GST activities were increased after B5 and B20 treatments; however, CYP1A mRNA induction was not observed. SOD and CAT activities were decreased, but GPx was significantly higher for all treatments in gills. There were no significant changes in lipid peroxidation, but genotoxicity markers revealed that all treatments increased comet scores. Fuels B5 and B20 increased micronuclei frequency. Our results indicate that despite being less toxic, biodiesel may cause sublethal alterations in fish that may alter long term health.
Assuntos
Biocombustíveis/toxicidade , Peixes-Gato/metabolismo , Sistema Enzimático do Citocromo P-450/metabolismo , Dano ao DNA , Animais , Catalase/metabolismo , Peixes-Gato/anatomia & histologia , Citocromo P-450 CYP1A1/metabolismo , Sistema Enzimático do Citocromo P-450/genética , Feminino , Gasolina/toxicidade , Brânquias/efeitos dos fármacos , Brânquias/enzimologia , Glutationa Peroxidase/metabolismo , Glutationa Transferase/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/enzimologia , Masculino , Estresse Oxidativo/efeitos dos fármacos , Superóxido Dismutase/metabolismoRESUMO
The success of the Asian bivalve Limnoperna fortunei as an invader in South America is related to its high acclimation capability. It can inhabit waters with a wide range of temperatures and salinity and handle long-term periods of air exposure. We describe the transcriptome of L. fortunei aiming to give a first insight into the phenotypic plasticity that allows non-native taxa to become established and widespread. We sequenced 95,219 reads from five main tissues of the mussel L. fortunei using Roche's 454 and assembled them to form a set of 84,063 unigenes (contigs and singletons) representing partial or complete gene sequences. We annotated 24,816 unigenes using a BLAST sequence similarity search against a NCBI nr database. Unigenes were divided into 20 eggNOG functional categories and 292 KEGG metabolic pathways. From the total unigenes, 1,351 represented putative full-length genes of which 73.2% were functionally annotated. We described the first partial and complete gene sequences in order to start understanding bivalve invasiveness. An expansion of the hsp70 gene family, seen also in other bivalves, is present in L. fortunei and could be involved in its adaptation to extreme environments, e.g. during intertidal periods. The presence of toll-like receptors gives a first insight into an immune system that could be more complex than previously assumed and may be involved in the prevention of disease and extinction when population densities are high. Finally, the apparent lack of special adaptations to extremely low O2 levels is a target worth pursuing for the development of a molecular control approach.
Assuntos
Mytilidae/genética , Transcriptoma , Animais , Perfilação da Expressão Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Espécies Introduzidas , FenótipoRESUMO
Every year thousands of new substances are synthetized and marketed. Either by regulatory demands or scientific purposes, these substances should all be tested. The determination of lethal concentration (LC) in a given population after toxicity testing in the laboratory is still the best way to establish and compare toxicity. In this technical note, we propose an R function to estimate LC with improvements on the choice of experimental design and calculation parameters, as well as in editing and spreadsheet loading. Although only LC50 values are considered herein, the same statistical considerations apply to EC50 and ED50 from quantal (dichotomous, binomial, binary) data. A running example is also provided.
Assuntos
Interpretação Estatística de Dados , Modelos Teóricos , Testes de Toxicidade/métodos , Animais , Concentração Inibidora 50 , Dose Letal MedianaRESUMO
Biological invasions currently pose major threats to ecosystems worldwide. Invasive bivalves such as the Golden Mussel Limnoperna fortunei can act as 'environmental engineers', altering biogeochemistry, reducing biodiversity, and literally changing the landscape of aquatic environments. The risk that this mussel will invade the Amazon basin is a great concern for environmental authorities, especially because no efficient control methods presently exist. In this study, we tested new microencapsulated chemicals, along with the traditional dissolved chlorine and KCl, as alternatives to control L. fortunei infestation in industrial and water supply plants along rivers. Because these bivalves can close their valves when they sense toxic substances in the water, microencapsulation has improved the effectiveness of the chemicals in controlling L. fortunei, reducing variation in the application and increasing toxicity compared to dissolved chemicals. Microencapsulation should be seriously considered as an alternative to replace hazardous chlorine.
Assuntos
Bivalves/efeitos dos fármacos , Desinfetantes/toxicidade , Espécies Introduzidas , Controle de Pragas , Animais , Compostos Clorados/toxicidade , Composição de Medicamentos , Dose Letal MedianaRESUMO
Hemocytes are the first line of defense of the immune system in invertebrates, but despite their important role and enormous potential for the study of gene-environment relationships, research has been impeded by a lack of consensus on their classification. Here we used flow cytometry combined with histological procedures, histochemical reactions and transmission electron microscopy to characterize the hemocytes from the oyster Crassostrea rhizophorae. Transmission electron microscopy revealed remarkable morphological characteristics, such as the presence of membranous cisternae in all mature cells, regardless of size and granulation. Some granular cells contained many cytoplasmic granules that communicated with each other through a network of channels, a feature never previously described for hemocytes. The positive reactions for esterase and acid phosphatase also indicated the presence of mature cells of all sizes and granule contents. Flow cytometry revealed a clear separation in complexity between agranular and granular populations, which could not be differentiated by size, with cells ranging from 2.5 to 25 µm. Based on this evidence we suggest that, at least in C. rhizophorae, the different subpopulations of hemocytes may in reality be different stages of one type of cell, which accumulates granules and loses complexity (with no reduction in size) as it degranulates in the event of an environmental challenge.
Assuntos
Hemócitos/citologia , Ostreidae/citologia , Animais , Citometria de Fluxo , Microscopia Eletrônica de TransmissãoRESUMO
The Amazon catfish genus Pterygoplichthys (Loricariidae, Siluriformes) is closely related to the loricariid genus Hypostomus, in which at least two species lack detectable ethoxyresorufin-O-deethylase (EROD) activity, typically catalyzed by cytochrome P450 1 (CYP1) enzymes. Pterygoplichthys sp. liver microsomes also lacked EROD, as well as activity with other substituted resorufins, but aryl hydrocarbon receptor agonists induced hepatic CYP1A mRNA and protein suggesting structural/functional differences in Pterygoplichthys CYP1s from those in other vertebrates. Comparing the sequences of CYP1As of Pterygoplichthys sp. and of two phylogenetically related siluriform species that do catalyze EROD (Ancistrus sp., Loricariidae and Corydoras sp., Callichthyidae) showed that these three proteins share amino acids at 17 positions that are not shared by any fish in a set of 24 other species. Pterygoplichthys and Ancistrus (the loricariids) have an additional 22 amino acid substitutions in common that are not shared by Corydoras or by other fish species. Pterygoplichthys has six exclusive amino acid substitutions. Molecular docking and dynamics simulations indicate that Pterygoplichthys CYP1A has a weak affinity for ER, which binds infrequently in a productive orientation, and in a less stable conformation than in CYP1As of species that catalyze EROD. ER also binds with the carbonyl moiety proximal to the heme iron. Pterygoplichthys CYP1A has amino acid substitutions that reduce the frequency of correctly oriented ER in the AS preventing the detection of EROD activity. The results indicate that loricariid CYP1As may have a peculiar substrate selectivity that differs from CYP1As of most vertebrate.
Assuntos
Peixes-Gato/metabolismo , Citocromo P-450 CYP1A1/química , Citocromo P-450 CYP1A1/metabolismo , Fígado/enzimologia , Microssomos Hepáticos/enzimologia , Substituição de Aminoácidos , Animais , Sequência de Bases , Citocromo P-450 CYP1A1/genética , Indução Enzimática , Proteínas de Peixes/química , Proteínas de Peixes/genética , Proteínas de Peixes/metabolismo , Fígado/metabolismo , Microssomos Hepáticos/metabolismo , Oxazinas/farmacologia , Bifenilos Policlorados/farmacologia , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Receptores de Hidrocarboneto Arílico/agonistas , Receptores de Hidrocarboneto Arílico/metabolismo , Alinhamento de Sequência , Análise de Sequência de DNA , Análise de Sequência de Proteína , Especificidade por Substrato , beta-Naftoflavona/farmacologiaRESUMO
Organochlorine pesticide (OCP) concentrations were determined in fish muscle and feed collected from four different fish farms in Brazil. Nile tilapia from two growth stages, juveniles and adults, collected at two intensive tanks farms (IT1 and IT2) and two net cage farms (NC1 and NC2), were analyzed by High Resolution Gas Chromatography/High Resolution Mass Spectrometry. Pesticides were detected in almost all samples, but no samples exceeded international maximum limits for safe fish consumption. ΣDDT was the predominant pesticide in fish muscle, found in all fish samples, and endosulfan was the most predominant pesticide in feed, found in all feed samples. No significant correlation (p>0.05) was observed between the different growth stages and OCP concentrations, although slightly higher OCP concentrations were observed in adults. Among the rearing systems, NC farmed fish presented higher lipid levels and, consequently, higher OCP concentrations than fish from IT farms. Some OCPs (ΣHCH, aldrin, dieldrin and endrin) presented strong positive correlations (p<0.05) between feed and fish muscle concentrations, while others (ΣDDT, mirex, chlordane, ΣHCB and endosulfan) presented no correlation. However, the low levels of the sum of contaminants found in most of the feed samples may explain the low contaminant levels in fish tissue.
Assuntos
Ração Animal/análise , Aquicultura , Hidrocarbonetos Clorados/análise , Músculos/química , Resíduos de Praguicidas/análise , Brasil , Cromatografia Gasosa-Espectrometria de Massas , Controle de QualidadeRESUMO
Antioxidant enzymes, total antioxidant capacity (TOSC) and concentration of reactive oxygen species (ROS) were measured in anterior (A), middle (M) and posterior (P) body regions of Laeonereis acuta after copper (Cu; 62.5 microg/l) exposure. A catalase (CAT) activity gradient observed in control group (lowest in A, highest in P) was not observed in Cu exposed group. Glutathione-S-transferase (GST) activity in A region of Cu group was higher than in A region of the control group. DNA damage (comet assay) was augmented in the A region of Cu group. Since copper accumulation was similar in the different body regions, sensitivity to copper in A regions seems to be related to lowest CAT activity. In sum, copper exposure lowered TOSC, a result that at least in part can be related to lowering of antioxidant enzymes like CAT. DNA damage was induced in the anterior region, where a lower CAT activity was observed.
Assuntos
Antioxidantes , Cobre/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Poliquetos/efeitos dos fármacos , Espécies Reativas de Oxigênio , Poluentes Químicos da Água/toxicidade , Animais , Antioxidantes/análise , Antioxidantes/metabolismo , Catalase/análise , Catalase/metabolismo , Ensaio Cometa , Dano ao DNA , Glutationa Transferase/análise , Glutationa Transferase/metabolismo , Estresse Oxidativo/fisiologia , Poliquetos/anatomia & histologia , Poliquetos/metabolismo , Espécies Reativas de Oxigênio/análise , Espécies Reativas de Oxigênio/metabolismoRESUMO
Over the last 20 years several projects carried on the Madeira River basin in the Amazon produced a great amount data on total Hg concentration in different fish species. In this paper we discuss temporal trends in Hg contamination and its relation to body weight in some of those fishes, showing that even within similar groups, such as carnivorous and non-migratory fish, the interspecies variability in Hg accumulation is considerable.
Vários estudos têm sido desenvolvidos nos últimos 20 anos na bacia do Rio Madeira (Amazônia) com o objetivo de diagnosticar a presença de mercúrio em peixes e compreender o ciclo deste elemento no meio ambiente tropical. Neste artigo são discutidas tendências temporais na concentração de Hg e sua relação com a massa corporal de algumas espécies de peixes com diferentes hábitos alimentares, coletadas no Rio Madeira e no reservatório da hidroelétrica de Samuel, no Rio Jamari, Estado de Rondônia. Foi avaliada uma amostragem de peixes de 14 anos (1987 - 2000) com 86 espécies e um total de 1100 espécimes.
Assuntos
Ecossistema Amazônico , Peixes , MercúrioRESUMO
Over the last 20 years several projects carried on the Madeira River basin in the Amazon produced a great amount data on total Hg concentration in different fish species. In this paper we discuss temporal trends in Hg contamination and its relation to body weight in some of those fishes, showing that even within similar groups, such as carnivorous and non-migratory fish, the interspecies variability in Hg accumulation is considerable.
Vários estudos têm sido desenvolvidos nos últimos 20 anos na bacia do Rio Madeira (Amazônia) com o objetivo de diagnosticar a presença de mercúrio em peixes e compreender o ciclo deste elemento no meio ambiente tropical. Neste artigo são discutidas tendências temporais na concentração de Hg e sua relação com a massa corporal de algumas espécies de peixes com diferentes hábitos alimentares, coletadas no Rio Madeira e no reservatório da hidroelétrica de Samuel, no Rio Jamari, Estado de Rondônia. Foi avaliada uma amostragem de peixes de 14 anos (1987 - 2000) com 86 espécies e um total de 1100 espécimes.
RESUMO
Fish is an important item in the diet of Amazonians, and per se is their best single source of essential nutrients. Rapid urbanization and migration are bringing changes in dietary habits of Amazonians. Exposure to fish-Hg during pregnancy and lactation were studied in 100 women and newborns from Porto Velho. Tissue-Hg concentrations and neurodevelopment (Gesell Developmental Schedules) were assessed at birth and at 6 months in exclusively breastfed infants. Maternal mean frequency of fish consumption was low (<2 meals/week; range 0->7 meals/week) compared to Amazonian standards. Women consuming <2 fish meals/week showed less median hair-Hg (3.5 microgg-1) than women that consumed 2 fish meals/week (5.7 microgg). Median total Hg in maternal hair (5.4 microgg-1) was higher than in newborns (1.6 microgg-1). Significant correlation was observed between maternal hair-Hg and infant hair-Hg at birth (r=0.353; p<0.01) and at six months (r=0.510; p<0.01). Placenta-Hg was also significantly correlated to maternal hair-Hg (r=0.321; p<0.01), newborn hair-Hg (r=0.219; p<0.05), maternal blood-Hg (r=0.250; p<0.01) and to umbilical cord-Hg (r=0.857; p<0.01). Most infants (74%) had normal Gesell Schedules but among the 26% showing neuro-motor development delays only six (7%) had multiple (motor, language, and adaptative) delays. The infants with multiple delays were born from mothers with range of hair-Hg comparable to mothers of normally developed infants. Coincidentally, mothers of infants with multiple delays also showed the lowest range of income and level of education. Fish consumption, income, and level of education varied greatly among these breastfeeding urban mothers. It seems that development delays of exclusively breastfed infants are a component of the health inequalities that accompanies socioeconomic disadvantages.
Assuntos
Aleitamento Materno , Contaminação de Alimentos , Exposição Materna/efeitos adversos , Mercúrio/toxicidade , Poluentes Químicos da Água/toxicidade , Adolescente , Adulto , Animais , Brasil , Monitoramento Ambiental , Feminino , Peixes , Cabelo/química , Humanos , Lactente , Recém-Nascido , Desenvolvimento da Linguagem , Mercúrio/análise , Mercúrio/sangue , Destreza Motora/efeitos dos fármacos , Placenta/química , Gravidez , Cordão Umbilical/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/sangueRESUMO
The Pregnane X Receptor (PXR) is a nuclear receptor involved in the transcriptional regulation of drug-metabolizing enzymes and transporters. In mammals, many xenobiotics induce the expression of cytochrome P4503A (CYP3A) and the multiple drug resistance 1 (MDR1) genes via the PXR pathway. Little attention has been given to studies about the identification and biological function of PXR homologues in non-mammalian species. Zebrafish is being widely used and accepted as model for toxicological and pharmacological studies to understand the mechanisms of human diseases and identify conserved signaling pathways. The aim of this study was to evaluate the in vivo expression of PXR, CYP3A and MDR1 genes in liver of zebrafish treated with the synthetic steroid pregnenolone 16alpha-carboninitrile (PCN), the antimycotic clotrimazole (CTZ) and the antianginal drug nifedipine (NIF). The liver of fish treated with PCN showed a 1.9-fold induction in the PXR followed by 1.8-fold induction in the CYP3A and 1.6-fold induction in the MDR1 mRNA. CTZ and NIF did not affect statistically the expression of PXR, CYP3A and MDR1. The similar pattern of mRNA expression of PXR, CYP3A and MDR1 genes found in fish treated with different PXR inducers suggests that the intrinsic association between these three genes is conserved in zebrafish.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Hidrocarboneto de Aril Hidroxilases/genética , Regulação da Expressão Gênica , Fígado/metabolismo , Oxirredutases N-Desmetilantes/genética , Receptores Citoplasmáticos e Nucleares/genética , Receptores de Esteroides/genética , Peixe-Zebra/metabolismo , Animais , Clotrimazol/farmacologia , Citocromo P-450 CYP3A , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Fígado/efeitos dos fármacos , Nifedipino/farmacologia , Receptor de Pregnano X , Carbonitrila de Pregnenolona/farmacologiaRESUMO
In order to study Zn and Cd accumulation and depuration, a set of oysters, Crassostrea rhizophorae, were transplanted to a metal contaminated coastal lagoon and another one was harvested there and transplanted to a non-polluted site. C. rhizophorae oysters and Perna perna mussels native from both sites were collected in order to monitor variability of metal concentration in resident populations. After three months exposure, oysters transplanted to the polluted site accumulated fourfold Zn (307-1319 microgg(-1)) without reaching the concentration level of resident oysters (9770 microgg(-1)). Cadmium concentrations had a slight but significant decrease during the same period (1.25-0.54 microgg(-1)). Oysters transplanted to the non-polluted site, showed threefold Zn depuration (6727-2404 microgg(-1)), while Cd had no significant variation (0.90-1.45 microgg(-1)). Results showed that transplanted oysters do not reach heavy metal concentrations in indigenous populations suggesting transplanted organisms would be better used to evaluate bioavailability instead of environmental concentrations.
Assuntos
Cádmio/farmacocinética , Ostreidae/fisiologia , Poluentes da Água/farmacocinética , Zinco/farmacocinética , Animais , Biodegradação Ambiental , Disponibilidade Biológica , Cádmio/isolamento & purificação , Distribuição Tecidual , Clima Tropical , Poluentes da Água/isolamento & purificação , Zinco/isolamento & purificaçãoRESUMO
We evaluated the indoor atmospheric Hg contamination in gold trade shops in two Brazilian cities of the Legal Amazon area using the Spanish moss (Tillandsia usneoides, Bromeliaceae) as a sentinel species. Plants inside plastic cages were exposed to a controlled atmosphere to evaluate the rate of Hg retention over time and then distributed in several stores with different characteristics to enable a relative comparison. Hg concentrations were determined by cold vapor atomic absorption spectrophotometry. Plants exposed in active stores with good air circulation exhibited lower levels. Ex-gold trade shops that were kept closed for long periods exhibited higher values. Stores that have been restored before being transformed into new businesses exhibited lower values than nonrestored ones. Direct measurements suggest that indoor Hg air concentrations were below the threshold limit recommended by the World Health Organization to occupational exposure; nevertheless, restoring ex-gold trade shops could ensure a healthier working environment.