RESUMO
Ultrastructural and phylogenetic description of a fish-infecting myxosporean found infecting the gallbladder wall of the teleostean Eugerres brasilianus Cuvier, 1830, collected from the Atlantic coast near the city of Maceió (Alagoas State), Brazil. Groups of mature pseudo-conical myxospores, agglutinated forming pseudocyst structures, occurring in the mucosa of gallbladder were 5.2 ± 0.8 µm (4.5-6.0) (n = 30) long, 4.3 ± 0.6 µm (3.8-4.7) (n = 25) thick, and 2.9 ± 0.2 µm (2.7-3.2) (n = 25) wide. The two ellipsoidal polar capsules, 1.8 ± 0.4 × 1.2 ± 0.4 µm (n = 25), opened close to the sutural line, each containing an isofilar polar tubule. The latter consisted of a single coil with five to six turns, arranged obliquely to the axis of the polar capsule. This myxosporean parasite, while being morphologically similar to Sphaerospora spp., displays tissue tropism and phylogenetic relationships distinct from the latter. Bayesian inference (BI) and maximum likelihood (ML) analyses showed the parasite and two other related species clustering within the marine clade, more specifically within a subclade of the larger Kudoa (Multivalvulida) clade. Consequently, this atypical new myxozoan species was classified as Kudoa eugerres n. sp. and two other histozoic Sphaerospora spp. sensu lato were transferred to the genus Kudoa.
Assuntos
Doenças dos Peixes/parasitologia , Myxozoa/classificação , Doenças Parasitárias em Animais/parasitologia , Animais , Teorema de Bayes , Brasil , DNA Ribossômico/química , Peixes/parasitologia , Vesícula Biliar/parasitologia , Myxozoa/genética , Myxozoa/isolamento & purificação , Filogenia , Análise de Sequência de DNARESUMO
Acetylcholinesterase (AChE) plays an important role in the therapy of Alzheimer's disease and in the detection of pesticides such as organophosphates which are also widely used in chemical warfare. The aim of this study is the physicochemical and kinetic characterization of brain and muscle ChE from Danio rerio (Zebrafish). Optimal activity was found for brain ChE at alkaline pHâ¯9.0 at 30⯰C, and for muscle ChE at alkaline pHâ¯8.5 at temperatures between 20⯰C and 35⯰C. The apparent kinetic constants, Kmapp and Vmaxapp, for brain ChE were determined as 0.191⯱â¯0.024â¯mM and 0.566⯱â¯0.028â¯U/mg protein, and for muscle ChE as 0.230⯱â¯0.030â¯mM and 0.677⯱â¯0.039â¯U/mg protein. Both brain and muscle ChE showed inhibition at high substrate concentrations. Brain and muscle ChE showed IC50 values for physostigmine of 0.61⯵M and 0.37⯵M, respectively. The ChE activity in brain was significantly inhibited by BW254c51 in all concentrations tested, but not by Iso-OMPA, while muscle ChE presented a moderate decrease (13 to 29%) in the activity values, indicating that BuChE is present.