Influência de fatores abióticos sob miogênese de peixes teleósteos / Abiotic influence in myogenesis of teleost fishes / Influencia abiótica en la miogénesis de peces teleósteos

Resumo Os peixes teleósteos são organismos que, geralmente, apresentam limite de crescimento indeterminado e estão presentes em diferentes biomas com diversas características ambientais. Os teleósteos possuem até 80% de sua composição corporal formado por tecido muscular, composto por fibras musculares e células satélites indiferenciadas, formando um tecido muscular complexo cuja forma é muito variada em função das espécies que compõem este grupo de animais. Um ponto importante a ser considerado é que o crescimento muscular dos peixes é influenciado pelas condições ambientais em que estão inseridos. Esta influência ocorre à nível molecular afetando a transcrição e funcionalidade de diferentes transcritos relacionados à miogênese em diferentes fases do desenvolvimento dos peixes. Esta revisão tem o objetivo de discutir alguns dos pontos chave sobre a influência dos fatores ambientais sobre o desenvolvimento e crescimento muscular dos peixes.

Abstract Teleost fish are organisms that generally show an indeterminate growth limit and are present in different biomes with different environmental conditions. Approximately up to 80% of the body composition of fish is formed by muscle tissue. Muscle tissue is composed of muscle fibers and undifferentiated satellite cells, forming a complex tissue that shows a widely varied shape depending on the species which form this group of animals. An important point to be considered is that the muscle growth of the fish is influenced by the environmental conditions in which they are inserted. This influence occurs at the molecular level, affecting the transcription and functionality of different transcripts related to myogenesis at different stages of fish development. This review aims to discuss some of the key aspects about the influence of environmental factors on the development and muscle growth of teleost fish.

Resumen Los peces teleósteos son organismos que generalmente tienen un límite de crecimiento indeterminado y están presentes en diferentes biomas con diferentes características ambientales. Los teleósteos poseen hasta el 80% de su composición corporal compuesta de tejido muscular, compuesto por fibras musculares y células satélite indiferenciadas, formando un tejido muscular complejo cuya forma es muy variada dependiendo de las especies que componen este grupo de animales. Un punto importante por considerar es que el crecimiento muscular de los peces está influenciado por las condiciones ambientales en que están inseridos. Esta influencia ocurre a nivel molecular, afectando la transcripción y la funcionalidad de diferentes transcripciones relacionadas con la miogénesis en diferentes etapas del desarrollo de los peces. Esta revisión tiene como objetivo discutir algunos de los puntos clave sobre la influencia de los factores ambientales en el desarrollo y el crecimiento muscular de los peces.

Beta-haemolytic streptococci in farmed Nile tilapia, Oreochromis niloticus, from Sullana-Piura, Peru / Estreptococos beta-hemolítico en tilapias del Nilo ( Oreochromis niloticus ) cultivadas en Sullana, Piura - Perú

ABSTRACT Objective. This investigation aimed to study the presence of Streptococcus spp. in tilapia (Oreochromis niloticus) from fish farm located in ​​Sullana-Piura, Peru. Materials and methods. 150 fish with clinical signs of streptococcal disease were sampled, and the bacterium isolation was performed on blood agar, correlated to histopathological lesions description and molecular confirmation by real-time PCR. Results. The necropsy revealed exophthalmia, hyphema, congestion and/or haemorrhagic meninges, ascites, splenomegaly, hepatomegaly and diffuse haemorrhagic zones throughout the body. 102 isolated positives (54 tilapias) to Streptococcus spp. were identified in the microbiological analysis (prevalence of 26%), the brain was the organ with the highest percentage of this bacteria (34.31%), and 19 isolates were beta-haemolytic (18.63%) with prevalence of 10.12%. Fish beta-haemolytic streptococci presented epicarditis, perisplenitis and chronic meningitis, panophthalmitis, coagulative necrosis of skeletal muscle and granulomas formation. In the confirmatory test by real-time PCR, any positive tilapia to S. iniae was obtained. The results were analysed using a stochastic simulation of beta distribution using @Risk program uncertainty, reporting an average prevalence of 0.66% in sick tilapias. Conclusions. The analysed fishes were positive to bacteria of the genus Streptococcus, which confirms its presence in the fish farm. However, 19 isolates were beta-haemolytic, and the presence of S. iniae was not positive to the limit prevalence of 2.7% in real-time PCR.

RESUMEN Objetivo. Esta investigación objetivó estudiar la presencia de Streptococcus spp. en tilapia (Oreochromis niloticus) de la piscifactoría localizada en Sullana-Piura, Perú. Materiales y Método. . 150 peces con signos clínicos de la enfermedad estreptocócica fueron analizados, el aislamiento bacteriano se realizó en agar sangre, en correlación con las lesiones histopatológicas y diagnóstico molecular mediante PCR en tiempo real. Resultados. A la necropsia se observó exoftalmia, hifema, congestión y/o meninges hemorrágicas, ascitis, esplenomegalia, hepatomegalia y zonas hemorrágicas difusas en todo el cuerpo. 102 aislados positivos (54) tilapias para Streptococcus spp. fueron identificados en el análisis microbiológico (prevalencia del 26%), el cerebro fue el órgano con el más alto porcentaje del género de esta bacteria (34.31%), 19 aislados fueron beta-hemolítico (18.63%), con prevalencia de 10.12%. Peces con Streptococcus beta-hemolíticos presentaron epicarditis, perisplenitis y meningitis crónica, panoftalmitis, necrosis coagulativa del músculo esquelético y formación de granulomas. En el análisis de PCR en tiempo real, no se obtuvo ninguna tilapia positiva para S. iniae. Los resultados se analizaron mediante una simulación estocástica de la distribución beta usando el programa de incertidumbre @Risk, reportando una prevalencia media de 0.66% en tilapias enfermas. Conclusiones. Los peces analizados fueron positivos para bacterias del género Streptococcus, lo que confirma su presencia en la piscifactoría. Sin embargo, 19 aislados fueron beta-hemolíticos, y la presencia de S. iniae no fue positiva para la prevalencia límite de 2.7% en PCR en tiempo real.

Estudio morfológico de la retina de salmones (Salmo salar) / Morphological study of the retina of salmon (Salmo salar)

La retina de peces teleósteos como pez cebra, se ha transformado en un importante modelo para el estudio de la plasticidad neuronal y la neurogénesis. Se ha demostrado además que la retina experimenta cambios ontogenéticos para adaptarse a distintos medios ambientes durante su vida. Este estudio tiene como objetivo describir el desarrollo ontogenético de la retina del alevín de salmón desde la eclosión hasta la fase de juvenil. Se trabajó con 30 salmones divididos en tres grupos de 10. Grupo I: recién eclosionados, con saco vitelino y 18 mm de longitud. Grupo II: sin saco vitelino y 30 mm de longitud. Grupo III: 100 mm de longitud. Cinco alevinesde cada grupo fueron procesados según el protocolo de Hanken & Wassersug para medir los diámetros dorsoventral y nasal-temporal utilizando el cartílago que protege al globo ocular. Los restantes cinco ejemplares fueron seccionados con micrótomo Microm en forma seriada (5 µm) y procesados con técnica H&E/Azul de Alcián. Se midieron las capas de la retina en un microscopio óptico Zeiss, con cámara Powershot incorporada y con un software Image Tool 3.0. El Grupo 1 presentó grandes ojos pigmentados, con aspecto de copa óptica embrionaria, la retina está estratificada en capas. La Capa Nuclear Interna (CNI) mide 62±10 µm y la capa plexiforme interna (CPI) 10±2 µm. El Grupo 2 presenta cambios en el espesor de ellas. La CNI disminuye su espesor a 45±8 µm y la Plexiforme aumenta a 25±5 µm. En los peces juveniles del Grupo 3, la CNI alcanza el espesor mínimo (15±3 µm), por el contrario, la capa Plexiforme interna aumenta su espesor hasta alcanzar (70±10 µm). En los tres grupos estudiados observamos en la periferia de la retina una zona proliferativa germinativa, que corresponde a un remanente del neuroepitelio embrionario, responsable del crecimiento continuado de la retina. La retina de los salmones puede ser también un importante modelo para el estudio de la ontogenia, la plasticidad neuronal y la neurogénesis. Esta neurogénesis en la retina de peces facilita la reordenación celular a lo largo de la ontogenia, lo que potencialmente permite la optimización del sistema visual a los cambios en las demandas visuales. Este estudio puede ser de utilidad para facilitar el diagnóstico en las patologías de ojo en salmonicultura y también puede contribuir a conocer mejor la regeneración de tejidos. Por otro lado, con estudios posteriores, la neurogénesis de la retina de peces podría extrapolarse al tratamiento de enfermedades humanas con daño a nivel retineal, tales como glaucoma, desprendimiento de retina y retinopatía diabética.

The retina of teleost fish zebrafish, has become an important model for studying neuronal plasticity and neurogenesis. It was further shown that the retina undergoes ontogenetic changes to adapt to different environments during their lifetime. This study aims to describe the ontogenetic development of the retina of juvenile salmon from hatching to the juvenile stage. We worked with 30 salmon divided into three groups of 10. Group I: newly hatched with yolk sac and 18 mm in length. Group II: without yolk sac and 30 mm in length. Group III: 100 mm long. Five fry each group were processed according to the protocol of Hanken & Wassersug to measure dorsoventral and nasal-temporal diameters using the cartilage that protects the eyeball. The remaining five specimens were sectioned with a microtome Microm serially (5 µm) and processed with technical H-E / Alcian blue. The layers of the retina were measured on a Zeiss optical microscope with camera Powershot built and with Image Tool 3.0 software. Group 1 showed large pigmented eyes, looking embryonic optic cup, the retina is stratified in layers. The inner nuclear layer (CNI) measured 62±10 microns and the inner plexiform layer (CPI) 10±2 µm. Group 2 presents changes in the thickness of them. The CNI decreases in thickness to 45±8 µm and the plexiform increased to 25±5 µm. In juvenile fish of group 3, the CNI reaches the minimum thickness (15±3 µm), by contrast, the inner plexiform layer thickness increases up to (70±10 µm). In the three groups observed in the periphery of the retina one proliferative germinative zone, which corresponds to a remnant of the embryonic neural epithelium responsible for the continued growth of the retina. The retina of the salmon can also be an important model for the study of ontogeny, neuronal plasticity and neurogenesis. This retinal neurogenesis fish rearrangement facilitates cell along ontogeny, potentially allowing optimization of the visual system to changes in the visual demands. This study may be useful to help diagnose pathologies in eye salmon and can also contribute to better understand tissue regeneration. On the other hand, with later studies, fish's retinal neurogenesis could be extrapolated to the treatment of human retinal diseases, such us glaucoma, retinal detachment o diabetic retinopathy.

Occurrence of Braga cigarra (Cymothoidae) parasitizing Galeocharax knerii (Characidae) from affluents of Jurumirim reservoir, Brazil / Ocorrência de Braga cigarra (Cymothoidae) parasitando Galeocharax knerii (Characidae) de afluentes da represa de Jurumirim, Brasil

The occurrence of the cymothoidae Braga cigarra is reported parasitizing the oral cavity of freshwater fish Galeocharax knerii from Veados, Paranapanema and Taquari Rivers, affluent of the Jurumirim Reservoir, State of São Paulo, Brazil is reported. The isopod species were identified based on the multilaminar pleopods, narrow pleon and short pleotelson in females. The overall prevalences of isopods were 31.7%, 7.7% and 5.7%, respectively, in the Paranapanema, Veados and Taquari Rivers. This note contributes to the knowledge of the geographical distribution and fauna of parasite crustaceans known to date in these important ecosystems.

Foi registrada a ocorrência do cymothoidae Braga cigarra parasitando a cavidade bucal do peixe de água doce Galeocharax knerii capturado nos rios Veados, Paranapanema e Taquari, afluentes da represa de Jurumirim, Estado de São Paulo, Brasil. As espécies de isópodas foram identificadas com base nos pleópodos multilaminares, abdômen estreito e pleotelson curto nas fêmeas. As prevalências totais de isópodos foram 31,7%, 7,7% e 5,7%, respectivamente, nos rios Paranapanema, Veados e Taquari. Essa nota contribui com o conhecimento da distribuição geográfica e da fauna de crustáceos parasitas conhecidas até a presente data nesses importantes ecossistemas aquáticos.

Chlorpheniramine impairs spatial choice learning in telencephalon-ablated fish

This work investigated the effect of the Hj receptor blockade in the forebrain of ablated Carassius auratus in a simple stimulus-response learning task using a T-maze test with positive reinforcement. The goldfish were submitted to surgery for removal of both telencephalic lobes five days before beginning the experiment. A T-shaped glass aquarium was employed, with two feeders located at the extremities of the long arm. One of the two feeders was blocked. The experimental triáis were performed in nine consecutive days. Each fish was individually placed in the short arm and confined there for thirty seconds, then it was allowed to swim through the aquarium to search for food for ten minutes (máximum period). Time to find food was analysed in seconds. Animáis were injected intraperitoneally with chlorpheniramine (CPA) at 16 mg/kg of body weight or saline after every trial, ten minutes after being placed back in the home aquarium. The results show that all the training latencies of the A-SAL group were higher than the latencies of the S-SAL group. The S-SAL group had decreased latencies from the second trial on, while the S-CPA group showed decreased latencies after the fourth trial. The A-SAL group showed reduced latencies after the fifth trial, but the A-CPA group mainteined the latencies throughout the experiment. This suggests that CPA impairs the consolidation of learning both on telencephalon ablated animáis and in sham-operated ones through its action on mesencephalic structures of the brain and/or on the cerebellum in teleost fish.

Gametogenesis and reproduction of the matrinxã Brycon orthotaenia (Günther, 1864) (Pisces: Characidae) in the São Francisco river, Minas Gerais, Brazil

The gametogenesis and reproduction of the matrinxã, Brycon orthotaenia in the São Francisco river, Pirapora Region, Minas Gerais, were studied from December, 1998 to November, 1999. The matrinxã B. orthotaenia is an endemic species in the São Francisco river basin in Brazil and important for commercial fishing. The size of the 1st gonadal maturation, indicated by the total length of the smallest spent males and spawned female, was 32.0 and 40.5 cm respectively. Reproduction occurred from October to January, when high frequencies of females and males at an advanced ripening/mature stage and spawned females were found. The short spawning period and histological characteristics of spawned ovaries containing only oocytes in stages of initial development, along with post-ovulatory and atresic follicles, indicated that Brycon orthotaenia presents total spawning.

Estudaram-se a gametogênese e a reprodução de Brycon orthotaenia do rio São Francisco, na região de Pirapora, Minas Gerais, no período de dezembro/1998 a novembro/1999. O matrinxã B. orthotaenia é uma espécie endêmica da bacia do rio São Francisco, Brasil e importante na pesca comercial. O tamanho de 1ª maturação gonadal, indicado pelo comprimento total do menor macho espermiado e da menor fêmea desovada, foi de 32,0 e 40,5 cm, respectivamente. A reprodução ocorreu de outubro a janeiro, quando observam-se altas freqüências de fêmeas e machos no estádio maturação avançada/maduro e fêmeas desovadas. O curto período de desova e as características histológicas de ovários desovados, contendo somente ovócitos nos estádios iniciais de desenvolvimento ao lado de folículos pós-ovulatórios e atrésicos, indicam que a desova de B. orthotaenia é do tipo total.