38 research outputs found
André DUNES, Documentation juridique, Paris, Dalloz, Coll. « Méthodes du droit », 1977, 198 pp., 46FF
Poor water quality condition has been pointed out as one of the major causes for the high mortality of ornamental fishes exported from the state of Amazonas, Brazil. The purpose of the current study was to define water quality standards for cardinal tetra (Paracheirodon axelrodi), by establishing the lower and higher for lethal temperature (LT50), lethal concentration (LC50) for total ammonia and nitrite and LC50 for acid and alkaline pH. According to the findings, cardinal tetra is rather tolerant to high temperature (33.3 ºC), to a wide pH range (acid pH=2.9 and alkaline pH=8.8) and to high total ammonia concentration (23.7 mg/L). However, temperatures below 19.6 ºC and nitrite concentrations above 1.1 mg/L NO2- may compromise fish survival especially during long shipment abroad.A má qualidade da água tem sido apontada como uma das maiores causas da alta mortalidade dos peixes ornamentais exportados pelo Estado do Amazonas, Brasil. A proposta deste estudo foi definir padrões de qualidade da água para o cardinal tetra (Paracheirodon axelrodi), estabelecendo a menor e a maior temperatura letal (LT50), a concentração letal (LC50) para amônia total e nitrito e LC50 para pH ácido e alcalino. De acordo com os resultados, o cardinal tetra é mais tolerante a temperaturas elevadas (33,3 ºC), a amplos limites de pH (pH ácido = 2,9 e pH alcalino = 8,8) e a alta concentração de amônia (23,7 mg/L). Entretanto, temperaturas abaixo de 19,6 ºC e concentrações de nitrito acima de 1,1 mg/L NO2- podem comprometer a sobrevivência dos peixes, especialmente durante longos períodos de transporte para o exterior
Identification of Potential Inhibitors from Pyriproxyfen with Insecticidal Activity by Virtual Screening
Aedes aegypti is the main vector of dengue fever transmission, yellow fever, Zika, and
chikungunya in tropical and subtropical regions and it is considered to cause health risks to millions
of people in the world. In this study, we search to obtain new molecules with insecticidal potential
against Ae. aegypti via virtual screening. Pyriproxyfen was chosen as a template compound to
search molecules in the database Zinc_Natural_Stock (ZNSt) with structural similarity using ROCS
(rapid overlay of chemical structures) and EON (electrostatic similarity) software, and in the final
search, the top 100 were selected. Subsequently, in silico pharmacokinetic and toxicological properties
were determined resulting in a total of 14 molecules, and these were submitted to the PASS online
server for the prediction of biological insecticide and acetylcholinesterase activities, and only two
selected molecules followed for the molecular docking study to evaluate the binding free energy
and interaction mode. After these procedures were performed, toxicity risk assessment such as LD50
values in mg/kg and toxicity class using the PROTOX online server, were undertaken. Molecule
ZINC00001624 presented potential for inhibition for the acetylcholinesterase enzyme (insect and
human) with a binding affinity value of -10.5 and -10.3 kcal/mol, respectively. The interaction with
the juvenile hormone was -11.4 kcal/mol for the molecule ZINC00001021. Molecules ZINC00001021
and ZINC00001624 had excellent predictions in all the steps of the study and may be indicated as the
most promising molecules resulting from the virtual screening of new insecticidal agents.Federal University of Amapá, Program in Biotechnology and Biodiversity-Network
BIONORTE, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) and Conselho Nacional de
Desenvolvimento Científico e Tecnológico (CNPq) for funding in the publication of this article
Red blood cell adrenergic responses in Amazonian teleosts
Erythrocytes from Amazonian teleosts of the Rio Negro were surveyed for the presence of adrenergically mediated Na+/H+ exchange. Washed red blood cells (RBCs) incubated in HEPES-buffered Cortland saline were stimulated with 10-4 M L-adrenaline. The adrenergic response was clearly present in two characids, the tambaqui Colossoma macropomom and the jaraqui Semaprochilodus insignis, as demonstrated by a decrease in the pH(c)-pH(i) gradient across the RBC membrane, an uptake of Na+ from the extracellular medium, and RBC swelling. The latter was signalled by increased mean corpuscular volume (MCV) and decreased mean corpuscular haemoglobin concentration (MCHC). The response did not occur in two other characids, the black piranha Serrasalmus rhombeus and the aracu Leporinus fasciatus or in two silurid catfish, the piranambu Pinirampus pirinampu and the acari-bodo, armoured catfish, Pterygoplichthys multiradiatus. In acari-bodo, the Na+/H+ exchange response was similarly lacking under anoxic conditions. Oxygenated/deoxygenated comparisons revealed the presence of a marked Root effect in jaraqui and its absence in acari-bodo. GTP dominated over ATP as the major intracellular phosphate in all six species. There were no significant changes in any nucleoside phosphate (ATP, ADP, AMP, GTP, GDP, or GMP) in response to adrenaline in any species