RESUMEN
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.
Asunto(s)
Ecosistema , Mytilidae , Femenino , Masculino , Animales , Mytilidae/genética , Citogenética , Cromosomas Sexuales/genética , CariotipificaciónRESUMEN
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.
Asunto(s)
Cíclidos/metabolismo , Microcistinas/toxicidad , Actinas/genética , Actinas/metabolismo , Animales , Cíclidos/genética , Regulación de la Expresión Génica/efectos de los fármacos , Glutatión Peroxidasa/genética , Glutatión Peroxidasa/metabolismo , Glutatión Transferasa/genética , Glutatión Transferasa/metabolismo , Inyecciones Intraperitoneales , Proteína Fosfatasa 1/genética , Proteína Fosfatasa 1/metabolismo , Proteína Fosfatasa 2/genética , Proteína Fosfatasa 2/metabolismoRESUMEN
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.
Asunto(s)
Bagres/metabolismo , Citocromo P-450 CYP1A1/química , Citocromo P-450 CYP1A1/metabolismo , Hígado/enzimología , Microsomas Hepáticos/enzimología , Sustitución de Aminoácidos , Animales , Secuencia de Bases , Citocromo P-450 CYP1A1/genética , Inducción Enzimática , Proteínas de Peces/química , Proteínas de Peces/genética , Proteínas de Peces/metabolismo , Hígado/metabolismo , Microsomas Hepáticos/metabolismo , Oxazinas/farmacología , Bifenilos Policlorados/farmacología , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Receptores de Hidrocarburo de Aril/agonistas , Receptores de Hidrocarburo de Aril/metabolismo , Alineación de Secuencia , Análisis de Secuencia de ADN , Análisis de Secuencia de Proteína , Especificidad por Sustrato , beta-naftoflavona/farmacologíaRESUMEN
A semi-quantitative RT-PCR protocol was developed to directly evaluate metallothionein (MT) mRNA expression in different tissues of mangrove oysters (Crassostrea rhizophorae), using beta-Actin (ACT) as a normalizing gene. Clones with high degree of identity from partial coding sequences were obtained for both MT and ACT. Although not statistically significant, high relative accumulation of MT mRNA was observed in the digestive gland (DGG), but not in the gills, from samples collected from both control and contaminated sites. Nevertheless, MT expression was not comparable to the high levels of metal in the contaminated oysters. Results indicate that the variation in relative MT mRNA levels from different samples of the same site could be due to multiple gene copies or different MT isoform induction.
Asunto(s)
Exposición a Riesgos Ambientales/análisis , Monitoreo del Ambiente/métodos , Metalotioneína/análisis , Ostreidae/química , Contaminantes del Agua/análisis , Actinas/genética , Animales , Biomarcadores/análisis , Cadmio/análisis , Cadmio/toxicidad , ADN Complementario/genética , Sistema Digestivo/química , Sistema Digestivo/metabolismo , Perfilación de la Expresión Génica , Branquias/química , Branquias/metabolismo , Metalotioneína/genética , ARN Mensajero/análisis , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Contaminantes del Agua/toxicidad , Zinc/análisis , Zinc/toxicidadRESUMEN
Because of the practical advantages of thre utilization of microorganisms in screening test for wastewater monitoring, the correlation between results of toxicity tests with bacterium and fish for a chemical mixed effluent was examined. Results showed correlation (r=0,74,n=31,pAsunto(s)
Peces
, Klebsiella/aislamiento & purificación
, Pruebas de Toxicidad
, Aguas Residuales
RESUMEN
Because of the practical advantages of thre utilization of microorganisms in screening test for wastewater monitoring, the correlation between results of toxicity tests with bacterium and fish for a chemical mixed effluent was examined. Results showed correlation (r=0,74,n=31,pAsunto(s)
Klebsiella/aislamiento & purificación
, Peces
, Pruebas de Toxicidad
, Aguas Residuales