Molecular phylogenetic relationship between Philometroides tahieli (Nematoda, Philometridae) and other philometrids from South America.

In South America, the family Philometridae is represented by several genera and species. In particular, Philometra and Philometroides are the most speciose genera. In Argentina, only Philometroides tahieli has been reported so far. The main objective of this study was to analyze the phylogenetic relationship between Ps. tahieli and other South American philometrids using molecular data. The molecular analysis was performed using a female specimen of Ps. tahieli found on the opercular muscle of a juvenile Micropogonias furnieri from brackish waters in Argentina. Phylogenetic relationships were studied based on partial sequences of the 18S rDNA and 28S rDNA genes. In the 18S rDNA tree, Ps. tahieli was mainly grouped with other Philometroides from freshwater hosts from China, sharing the site of infection (head tissues or muscles). In the 28S rDNA tree, obtained with fewer sequences, Ps. tahieli is related species from subcutaneous tissues of head. This study contributes with information on philometrids and confirms the presence of different lineages among South American species, with Ps. tahieli representing a new one. Further studies on South American species using more molecular markers and new morphological characters will improve our knowledge of philometrid biodiversity and phylogeny.

The adductor pectoral fin muscle of Micropogonias furnieri (Perciformes: Sciaenidae): a morphological and histochemical study

The adductor pectoral fin muscle in post-spawning females of the white croaker Micropogonias furnieri (Desmarest, 1823) is described from a morphological, histochemical and morphometric perspectives. A description of the morphological characteristics was conducted after dissections in different layers, down to the deep layer. Five muscles were found: superficial, medial, radial and deep adductors, and dorsal arrector. Their fibers were studied after applying histochemical techniques: succinic dehydrogenase (SDH) to reveal mitochondria, periodic acid-Schiff (PAS) for glycogen, Sudan black for lipids, myosin adenosinetriphosphatase (mATPase) to reveal the types of fibers, and modified mATPase to evidence the capillaries. Fiber diameters were measured and the number of capillaries was counted. Fiber subtypes named small, medium and large were found within red, pink and white fibers, the latter prevailing. Staining homogeneity was observed in white fibers after alkaline pre-incubations. The number of capillaries decreased from red to white fibers. Due to the prevalence of white fibers, the adductor muscle of the pectoral fins appears to be capable of rapid and discontinuous movements, which are important to body stabilization during subcarangiform swimming. The homogenous staining of white fibers observed in this research corresponds to the post-spawning gonad stage studied.(AU)

The adductor pectoral fin muscle of Micropogonias furnieri (Perciformes: Sciaenidae): a morphological and histochemical study

The adductor pectoral fin muscle in post-spawning females of the white croaker Micropogonias furnieri (Desmarest, 1823) is described from a morphological, histochemical and morphometric perspectives. A description of the morphological characteristics was conducted after dissections in different layers, down to the deep layer. Five muscles were found: superficial, medial, radial and deep adductors, and dorsal arrector. Their fibers were studied after applying histochemical techniques: succinic dehydrogenase (SDH) to reveal mitochondria, periodic acid-Schiff (PAS) for glycogen, Sudan black for lipids, myosin adenosinetriphosphatase (mATPase) to reveal the types of fibers, and modified mATPase to evidence the capillaries. Fiber diameters were measured and the number of capillaries was counted. Fiber subtypes named small, medium and large were found within red, pink and white fibers, the latter prevailing. Staining homogeneity was observed in white fibers after alkaline pre-incubations. The number of capillaries decreased from red to white fibers. Due to the prevalence of white fibers, the adductor muscle of the pectoral fins appears to be capable of rapid and discontinuous movements, which are important to body stabilization during subcarangiform swimming. The homogenous staining of white fibers observed in this research corresponds to the post-spawning gonad stage studied.

17,20 beta-P and cortisol are the main in vitro metabolites of 17-hydroxy-progesterone produced by spermiating testes of Micropogonias furnieri (Desmarest, 1823) (Perciformes Sciaenidae)

The aim was to investigate the major C21 steroids produced by spermiating white croaker Micropogonias furnieri (Sciaenidae) in order to establish the potential mediator of gamete maturation in males of this species. The testes steroid production at the spawning season was identified incubating the 3H-17-hydroxy-4-pregnene-3,20-dione precursor through thin layer chromatography, high pressure liquid chromatography, enzymatic oxydation, acetylation and immunochemistry analyses. 17,20β-Dihydroxy-4-pregnen-3-one (17,20β-P) and 11β,17,21-Trihydroxy-4-pregnene-3,20-dione (cortisol) were the main metabolites produced. Contrary to what we expected, 17,20β,21-Trihydroxy-4-pregnen-3-one was not detected. Circulating levels of 17,20β-P were undetectable in immature testes and in those at the first spermatogenesis stages, while a clear increase was observed during the whole spermatogenesis and spermiation phases (from undetectable to 1047 pg mL-1). In vitro studies together with plasma detection suggest that 17,20β-P is a good steroid candidate involved in M. furnieri testes maturation. The role of cortisol during late phases of testes development needs further studies.(AU)

El objetivo fue investigar cuales eran los esteroides C21 más importantes producidos por los testículos en espermiación de la corvina blanca Micropogonias furnieri (Sciaenidae) para poder identificar los potenciales mediadores de la maduración gamética de los machos de esta especie. Los esteroides producidos por los testículos en espermiación fueron identificados después de su incubación con el precursor 3H-17-hidroxi-4-pregnene-3,20-diona a través de cromatografía de capa fina y cromatografía líquida de alta presión y posteriormente por oxidación enzimática, acetilación e inmunoquímica. Los principales metabolitos producidos por los testículos en espermiación fueron la 17,20β-Dihidroxi-4-pregnen-3-ona (17,20β-P) y la 11β,17,21-Trihidroxi-4-pregnene-3,20-diona (cortisol). Contrariamente a lo esperado, no se encontró el derivado tri-hidroxilado de la progesterona llamado 17,20β,21-Trihidroxi-4-pregnen-3-ona. Los niveles circulantes de 17,20β-P fueron no detectable en los testículos inmaduros y en aquellos en inicios de espermatogénesis, mientras que un aumento claro en las concentraciones circulantes fue detectada en corvinas en plena espermatogénesis y en espermiación (desde no detectable a 1047 pg mL-1). Los resultados obtenidos in vitrojunto a los cambios a nivel plasmático sugieren que la 17,20β-P es un buen candidato a proponer como esteroide involucrado en la regulación del proceso de maduración testicular de la corvina. La función del cortisol a nivel testicular debería ser mejor estudiada en las etapas finales del desarrollo testicular de esta especie.(AU)

17,20 beta-P and cortisol are the main in vitro metabolites of 17-hydroxy-progesterone produced by spermiating testes of Micropogonias furnieri (Desmarest, 1823) (Perciformes Sciaenidae)

The aim was to investigate the major C21 steroids produced by spermiating white croaker Micropogonias furnieri (Sciaenidae) in order to establish the potential mediator of gamete maturation in males of this species. The testes steroid production at the spawning season was identified incubating the 3H-17-hydroxy-4-pregnene-3,20-dione precursor through thin layer chromatography, high pressure liquid chromatography, enzymatic oxydation, acetylation and immunochemistry analyses. 17,20β-Dihydroxy-4-pregnen-3-one (17,20β-P) and 11β,17,21-Trihydroxy-4-pregnene-3,20-dione (cortisol) were the main metabolites produced. Contrary to what we expected, 17,20β,21-Trihydroxy-4-pregnen-3-one was not detected. Circulating levels of 17,20β-P were undetectable in immature testes and in those at the first spermatogenesis stages, while a clear increase was observed during the whole spermatogenesis and spermiation phases (from undetectable to 1047 pg mL-1). In vitro studies together with plasma detection suggest that 17,20β-P is a good steroid candidate involved in M. furnieri testes maturation. The role of cortisol during late phases of testes development needs further studies.

El objetivo fue investigar cuales eran los esteroides C21 más importantes producidos por los testículos en espermiación de la corvina blanca Micropogonias furnieri (Sciaenidae) para poder identificar los potenciales mediadores de la maduración gamética de los machos de esta especie. Los esteroides producidos por los testículos en espermiación fueron identificados después de su incubación con el precursor 3H-17-hidroxi-4-pregnene-3,20-diona a través de cromatografía de capa fina y cromatografía líquida de alta presión y posteriormente por oxidación enzimática, acetilación e inmunoquímica. Los principales metabolitos producidos por los testículos en espermiación fueron la 17,20β-Dihidroxi-4-pregnen-3-ona (17,20β-P) y la 11β,17,21-Trihidroxi-4-pregnene-3,20-diona (cortisol). Contrariamente a lo esperado, no se encontró el derivado tri-hidroxilado de la progesterona llamado 17,20β,21-Trihidroxi-4-pregnen-3-ona. Los niveles circulantes de 17,20β-P fueron no detectable en los testículos inmaduros y en aquellos en inicios de espermatogénesis, mientras que un aumento claro en las concentraciones circulantes fue detectada en corvinas en plena espermatogénesis y en espermiación (desde no detectable a 1047 pg mL-1). Los resultados obtenidos in vitrojunto a los cambios a nivel plasmático sugieren que la 17,20β-P es un buen candidato a proponer como esteroide involucrado en la regulación del proceso de maduración testicular de la corvina. La función del cortisol a nivel testicular debería ser mejor estudiada en las etapas finales del desarrollo testicular de esta especie.

Pilot study about fish self-consumption among artisanal fishermen in Patos Lagoon estuary, RS, Brazil / Estudo piloto sobre o autoconsumo de pescado entre pescadores artesanais do estuário da Lagoa dos Patos, RS, Brasil

The artisanal fishery in Patos Lagoon estuary is a traditional activity. The main target species are mullet Mugil liza, white-croaker Micropogonias furnieri and pink-shrimp Farfantepenaeus paulensis. It is common for fishermen to consume the fish caught by them (self-consumption), what is believed to be important in certain communities. This study aims to estimate quantitatively and qualitatively the self-consumption of fish in three fishing communities of Rio Grande city. From September 2010 to December 2011, ten fishermen from each community were periodically interviewed for collecting information about fisheries and fish self-consumption. The mean per capita consumption of fish found was 109 g day-1, and 38.57 kg year-1. The higher mean daily self-consumption was found for spring (161 g/person) and summer (162 g/person), being the white croaker and the pink shrimp, respectively, the main consumed species. The fish is an important source of food to the artisanal fisherman of the studied communities.

A pesca artesanal no estuário da Lagoa dos Patos é uma atividade tradicional. As principais espécies-alvo são a tainha Mugil liza, a corvina Micropogonias furnieri e o camarão-rosa Farfantepenaeus paulensis. É comum que pescadores consumam parte do que capturam (autoconsumo), o que pode ser significativo em certas comunidades. Neste trabalho objetivou-se estimar quali-quantitativamente o autoconsumo de pescado em três comunidades pesqueiras do município de Rio Grande. Entre setembro de 2010 e dezembro de 2011 foram entrevistados, periodicamente, 10 pescadores de cada comunidade, coletando-se informações sobre a pescaria e a quantidade de pescado consumida. A média de consumo per capita de pescado foi de 109 g dia-1 e 38,57 kg ano-1. O autoconsumo médio diário foi maior na primavera (161 g/pessoa) e no verão (162 g/pessoa), sendo a corvina e o camarão-rosa, respectivamente, as principais espécies consumidas. Os resultados indicaram que o pescado é importante fonte de alimento para os pescadores artesanais das comunidades.