Efecto de la temperatura sobre la morfología y reproducción en el erizo de mar Arbacia dufresnii (Echinodermata: Echinoidea) / Effect of temperature on morphology and reproduction of sea urchin, Arbacia dufresnii (Echinodermata: Echinoidea)

Introducción: El aumento de los valores del CO2 atmosférico y el consecuente calentamiento del agua de mar constituyen factores de estrés para los ecosistemas marinos, renovando el interés en la fisiología de los equinoideos. El equinoideo Arbacia dufresnii es una especie ampliamente estudiada y con amplia distribución en los golfos norpatagónicos. Objetivo: Evaluar el efecto de temperatura del agua de mar sobre su morfología y reproducción. Métodos: Individuos de A. dufresnii fueron expuestos durante 10 semanas (Abril-Junio 2016) a tres tratamientos de temperatura (13 °C control, 15 °C y 17 °C) de acuerdo con las condiciones actuales del agua de mar y los valores esperados para el próximo siglo, según diferentes escenarios estimados. Al finalizar el experimento, diámetro y peso del individuo así como los pesos de los órganos internos fueron estadística e histológicamente analizados. Resultados: Se observó una mayor mortalidad en los individuos expuestos a las mayores temperaturas lo que podría deberse a un estrés en el individuo. Para el tratamiento control y el de 17 °C no se observaron cambios en los pesos secos de gónadas e intestino. En cambio, los individuos expuestos a 15 °C presentaron un aumento en el diámetro del caparazón y en el peso seco de gónadas e intestino. Los estadios gonadales aesta temperatura (15 °C) para machos fueron similares al ambiente a diferencia de las hembras que se observaron estadios más avanzados. Conclusiones: Esto indicaría que 15 °C podría ser la temperatura óptima para la asimilación del alimento y obtención de energía. A esta temperatura se observan cambios a corto plazo en los órganos de metabolismo rápido pero no en los órganos calcificados (caparazón y linterna de Aristóteles).

Introduction: The increase in atmospheric CO2 values and the consequent warming of seawater constitute stressors for marine ecosystems, renovating interest in echinoid physiology. The echinoid Arbacia dufresnii is a widely studied species with a wide distribution in the North Patagonian gulfs. Objective: Evaluate the effect of seawater temperature on its morphology and reproduction. Methods: Individuals were exposed for 10 weeks (April-June 2016) to three temperature treatments (13 °C control, 15 °C and 17 °C) according to the current conditions of seawater and the expected values for the next century. At the end of the experiment, diameter and weight of the whole individual and of its internal organs were statistically and histologically analyzed. Results: Individuals exposed to higher temperatures died in greater numbers. The control, and the 17 °C treatment, had no changes in dry gonad and intestine weights. However, the 15 °C group had wider diameter of test and a higher dry weight of gonads and intestine. At this temperature, the gonadal stages for males were similar to the environment, but females had more advanced stages. Conclusions: Temperature of 15°C could be optimal for assimilating food and obtaining energy. Gonads and intestine would be showing changes in the short term, unlike the calcified organs (test and Aristotle's lantern).

Reproductive cycle of Mytella guyanensis (Lamarck, 1819) in a Marine Reserve (RESEX Bay of Iguape), Bahia, Brazil / Ciclo reprodutivo de Mytella guyanensis (Lamarck, 1819) na Reserva Extrativista Marinha Baía do Iguape, Bahia, Brasil

Abstract Mytella guyanensis, consumed and commercialized in coastal regions of Brazil, is one of several bivalve species of socioeconomic interest for coastal communities. Besides serving as a source of income and subsistence for these communities, it also contributes to their food security as it is a source of proteins and micronutrients. Thus, the reproductive cycle of this species was studied aiming to contribute to food security and its preservation. Samples were collected monthly, between March 2014 and March 2015, in a natural stock (12°38'50"S; 38°51'43"W) in a Marine Reserve (RESEX Bay of Iguape) (community Engenho da Ponte), Bahia, Brazil. Mytella guyanensis is collected by women on site, where the artisanal fishing of this resource is performed without following any specific handling procedure. Also, empirical evidence indicates overexploitation. The specimens collected were measured along the anterior-posterior axis (length), and after macroscopic analysis they were fixed in Davidson solution, processed by routine histology techniques and stained with Harris haematoxylin and eosin (H&E). The macroscopic analysis showed sexual dimorphism, with the male and female gonads presenting a milky-white and orange colour, respectively. A 1:1 sex ratio (M: F) was observed and reproduction of the species was continuous all year round. March, April, July and August were the months with highest values of gamete elimination. We suggest that a M. guyanensis management plan should restrict capture during these months, in order to sustainably regulate exploitation of this food resource in this reserve.

Resumo Mytella guyanensis, consumida e comercializada em regiões litorâneas do Brasil, é uma das diversas espécies de bivalves de interesse socioeconômico para comunidades litorâneas. Além de servir como fonte de renda e subsistência para essas comunidades, esta contribui para a sua segurança alimentar, por ser fonte de proteínas e micronutrientes. Assim, o ciclo reprodutivo desta espécie foi estudado visando contribuir com a segurança alimentar e a preservação da mesma. As amostragens foram realizadas mensalmente, entre março de 2014 e março de 2015 em um estoque natural (12°38'50"S e 38°51'43"W) na Reserva Extrativista Marinha Baía do Iguape (comunidade Engenho da Ponte), Bahia. Mytella guyanensis é coletada no local por mulheres, onde a pesca artesanal desse recurso é realizada sem seguir nenhum procedimento específico de manejo e evidência empírica indica sobrexplotação. Os espécimes coletados foram medidos ao longo do eixo ântero-posterior (comprimento) e após a análise macroscópica, foram fixados em solução de Davidson, processados por técnicas rotineiras de histologia e coradas em hematoxilina de Harris e eosina (HE). A análise macroscópica evidenciou dimorfismo sexual, com as gônadas de machos e fêmeas apresentando coloração branco leitosa e alaranjada, respectivamente. Uma proporção sexual (M: F) de 1:1 foi observada e a reprodução foi contínua ao longo do ano. Março, abril, julho e agosto apresentaram os maiores valores de eliminação de gametas. Sugerimos que um plano de manejo de M. guyanensis restrinja a captura deste durante esses meses, a fim de regular de forma sustentável a exploração desse recurso nesta reserva.

Caracteres estructurales y ultraestructurales de la gametogénesis de Chara hydropitys (Charophyceae) / Structural and ultrastructural characters of the gametogenesis of Chara hydropitys (Charophyceae)

Resumen Los oosporangios y anteridios de Charophyceae son los órganos de reproducción sexual femeninos y masculinos respectivamente. Estas estructuras se caracterizan por su complejidad morfológica y utilidad en taxonomía y sistemática. En el presente trabajo se describen los detalles estructurales y ultraestructurales de la gametogénesis en Chara hydropitys. El material fértil del alga se recolectó en una quebrada tributaria del Río Meléndez en la ciudad de Cali, Colombia (3º21´23´´N - 76º32´5.2´´W). Los especímenes fueron fijados y procesados de acuerdo a los protocolos estándar para la inclusión en resina y obtención de secciones finas que se colorearon con toluidina O (0.3-0.7 μm) para su observación en microscopía fotónica y secciones ultrafinas (60-90 nm) para microscopía electrónica de transmisión (MET). Además, se procesaron muestras para microscopio electrónico de barrido (MEB). Los oosporangios están recubiertos por las células espirales que forman de 10-12 circunvoluciones y terminan en cinco células coronulares. La pared de los oosporangios inmaduros está formada por dos capas que corresponden a la pared de las células espirales y de la oosfera. Al madurar la pared del oosporangio tiene seis capas adicionales, tres de las cuales son aportadas por la oospora y las tres restantes por las células espirales. La oosfera aumenta progresivamente de tamaño a medida que las células espirales crecen y se dividen. En el citoplasma de la oosfera inmadura no se aprecian inclusiones citoplasmáticas conspicuas, pero con la maduración el número de gránulos de almidón aumenta llegando a ocupar la mayor parte del volumen celular. En las células espirales del oosporangio maduro se observan numerosos cloroplastos con prominentes depósitos de almidón entre las lamelas tilacoidales y una vacuola que ocupa casi toda la célula. En las observaciones con MEB se aprecia que la pared externa de la oospora, sobre la zona de la fosa presenta microornamentaciones de tipo verrucado. En los anteridios maduros las células del escudo están fuertemente pigmentadas de color naranja por la presencia de numerosos plastoglóbulos entre las lamelas tilacoidales. De las células del capítulo secundario se desarrollan los filamentos espermatógenos que por divisiones mitóticas unidireccionales y sincrónicas forman los espermatocitos. A partir de estas células haploides por espermiogénesis se desarrollarán los anterozoides biflagelados. Los eventos subcelulares relacionados con estos procesos de división y diferenciación celular incluyen inicialmente cambios en la condensación de la cromatina, pérdida del nucléolo y mayor actividad de los dictiosomas. Posteriormente, el citoplasma se retrae y los orgánulos se alinean a lo largo del núcleo condensado y del aparato flagelar. Los anterozoides maduros emergen a través de un poro lateral de la pared de los espermatocitos. Todos los eventos descritos indican que los procesos de gametogénesis y los detalles estructurales de los gametos son por lo general características ampliamente conservadas en este grupo de algas.

Abstract InCharophyceae, the oosporangia and antheridia are the respective female and male structures of sexual reproduction. These organs are characterized by their morphological complexity and usefulness in taxonomy and systematics. Here we described the structural and ultraestructural details of Chara hydropitys gametogenesis. The fertile material from the algae was collected in a tributary stream of the Río Meléndez in Cali, Colombia (3º21´23´´N - 76º32´5.2´´W) in March 2011. The specimens were fixed and processed following the standard protocols for inclusion in resin. Thin sections (0.3-0.5 μm) were stained with toluidine O, and were observed by photonic microscopy, and additional ultrathin sections (60-90 nm) were observed by transmission electron microscopy (TEM); other samples were processed and observed by scanning electron microscopy (SEM). We found that the oosporangia are covered with spiral cells, forming 10-12 convolutions and ends in five coronula cells. The immature oosporangia wall is formed by two layers that correspond to the wall of the spiral cells and to the oosphere. In mature stages, the oosporangia wall is composed by six additional layers, three of them are provided by the oosphere and the other three are provided by the spiral cells. Oosphere size increases progressively while the spiral cells grow and divide. The cytoplasm of the immature oosphere does not exhibit conspicuous cytoplasmic inclusions, nevertheless, with the maturation, the number of starch granules increases, occupying most of the cell volume. In the spiral cells of the mature oosporangia we observed large number of chloroplast with starch accumulations, between thylakoid lamellae and a vacuole that occupies almost the entire cell. By using SEM it was possible to appreciate, that the external wall of the oospore, more accurately, on the fossa area, shows verrucose micro-ornamentations with verrucae elevations. In mature antheridia, shield cells are strongly pigmented orange due to the presence of a large number of plastoglobules between thylakoid lamellae. The spermatogenous filaments are developed from cells of the secondary capitulum; those, by unidirectional and sincronic mitotic divisions develop the spermatocytes. The biflagellate antherozoids are developed from the haploid cells by spermiogenesis. The subcellular events related with these division and differentiation processes, include first, chromatin condensation, loss of nucleoli and more activity in dictyosomes. Subsequently, retracts the cytoplasm and the organelles are aligned along the condensed nucleus and flagellar apparatus. Mature antherozoids emerge through a side wall pore of the spermatocytes. All the described events showed that the gametogenesis processes and the gametes structural details in general, are widely conserved in this algae group.

Gonadal development of Peprilus medius (Peters, 1869) (Perciformes: Stromateidae) from Southeast of the Gulf of California, Mexico / Desarrollo gonádico de Peprilus medius (Peters, 1869) (Perciformes: Stromateidae) del Sureste del Golfo de California, México

The gonadal development assessment is a fundamental work in researching the reproduction of Peprilus medius, on the way to understand its population dynamics and to achieve a sustainable management of its fisheries. The diagnosis based on morphochromatic features is the quicker, more practical and cheaper method, and properly validated, it may be an accurate procedure. This is particularly useful in researches when it is required to provide prompt and accurate information to support decision-making for fisheries management, and during long-term fisheries monitoring to detect changes in reproductive patterns due to environmental anomalies. These are issues of concern in P. medius and other fishery resources. In this context, a scale that describes the gonadal development through morphochromatic and histological features is presented, and plus anatomical observations of the reproductive organs. Ovarian development was characterized through six phases: immature, development (sub-phases: early and late), mature, spawning (sub-phases: partial and partial post-spawning), post-spawning and resting. Testicular development was described through five phases: immature, development, ejaculation, ejaculated and resting. The position and shape of the reproductive organs are apparently defined by the shape of the fish and the visceral cavity. P. medius's gonads show a gonadal lobe at lower position and an upper lobe in the visceral cavity, and both lobes presented a horizontal placement from gonopore toward the back of the fish. In addition, gonadal deformities occurrence due to deformities in the visceral cavity was evidenced. We recommend to use presented descriptions as a guide in gonadal assessment.

La evaluación del desarrollo gonádico es una labor fundamental para investigar la reproducción de Peprilus medius, en vías a comprender la dinámica de sus poblaciones y lograr un manejo sustentable de sus pesquerías. El diagnóstico a partir de características morfocromáticas es el método más rápido, práctico y barato, y adecuadamente validado puede ser un procedimiento preciso. Este es particularmente útil en investigaciones cuando se requiere aportar información rápida y precisa que apoye la toma de decisiones de manejo pesquero, y durante los monitoreos pesqueros de largo plazo, que permiten detectar cambios en los patrones reproductivos debido a anomalías ambientales. Estos son temas preocupantes en P. medius y otros recursos pesqueros. En ese contexto se presenta una escala que describe el desarrollo gonádico a través de características morfocromáticas e histológicas, y además se presentan observaciones anatómicas de los órganos reproductores. El desarrollo ovárico fue caracterizado a través de seis fases: inmadura, desarrollo (subfases: inicial y avanzado), maduro, desove (subfases: parcial y postdesove parcial), postdesove y reposo. El desarrollo testicular fue descrito a través de cinco fases: inmadura, desarrollo, eyaculación y reposo. La posición y forma de los órganos reproductores están aparentemente definidos por la forma del pez y su cavidad visceral. Las gónadas de P. medius muestran un lóbulo gonádico en posición inferior y uno superior en la cavidad visceral, y ambos lóbulos presentan una colocación horizontal desde el gonoporo hacia la parte posterior del pez. Además se evidencia la ocurrencia de deformidades en las gónadas debido a deformidades en la cavidad visceral. Recomendamos utilizar las descripciones presentadas como una guía en la evaluación de las gónadas.

Reproductive cycle of Mytella guyanensis (Lamarck, 1819) in a Marine Reserve (RESEX Bay of Iguape), Bahia, Brazil

Abstract Mytella guyanensis, consumed and commercialized in coastal regions of Brazil, is one of several bivalve species of socioeconomic interest for coastal communities. Besides serving as a source of income and subsistence for these communities, it also contributes to their food security as it is a source of proteins and micronutrients. Thus, the reproductive cycle of this species was studied aiming to contribute to food security and its preservation. Samples were collected monthly, between March 2014 and March 2015, in a natural stock (12°38'50S; 38°51'43W) in a Marine Reserve (RESEX Bay of Iguape) (community Engenho da Ponte), Bahia, Brazil. Mytella guyanensis is collected by women on site, where the artisanal fishing of this resource is performed without following any specific handling procedure. Also, empirical evidence indicates overexploitation. The specimens collected were measured along the anterior-posterior axis (length), and after macroscopic analysis they were fixed in Davidson solution, processed by routine histology techniques and stained with Harris haematoxylin and eosin (H&E). The macroscopic analysis showed sexual dimorphism, with the male and female gonads presenting a milky-white and orange colour, respectively. A 1:1 sex ratio (M: F) was observed and reproduction of the species was continuous all year round. March, April, July and August were the months with highest values of gamete elimination. We suggest that a M. guyanensis management plan should restrict capture during these months, in order to sustainably regulate exploitation of this food resource in this reserve.

Resumo Mytella guyanensis, consumida e comercializada em regiões litorâneas do Brasil, é uma das diversas espécies de bivalves de interesse socioeconômico para comunidades litorâneas. Além de servir como fonte de renda e subsistência para essas comunidades, esta contribui para a sua segurança alimentar, por ser fonte de proteínas e micronutrientes. Assim, o ciclo reprodutivo desta espécie foi estudado visando contribuir com a segurança alimentar e a preservação da mesma. As amostragens foram realizadas mensalmente, entre março de 2014 e março de 2015 em um estoque natural (12°38'50S e 38°51'43W) na Reserva Extrativista Marinha Baía do Iguape (comunidade Engenho da Ponte), Bahia. Mytella guyanensis é coletada no local por mulheres, onde a pesca artesanal desse recurso é realizada sem seguir nenhum procedimento específico de manejo e evidência empírica indica sobrexplotação. Os espécimes coletados foram medidos ao longo do eixo ântero-posterior (comprimento) e após a análise macroscópica, foram fixados em solução de Davidson, processados por técnicas rotineiras de histologia e coradas em hematoxilina de Harris e eosina (HE). A análise macroscópica evidenciou dimorfismo sexual, com as gônadas de machos e fêmeas apresentando coloração branco leitosa e alaranjada, respectivamente. Uma proporção sexual (M: F) de 1:1 foi observada e a reprodução foi contínua ao longo do ano. Março, abril, julho e agosto apresentaram os maiores valores de eliminação de gametas. Sugerimos que um plano de manejo de M. guyanensis restrinja a captura deste durante esses meses, a fim de regular de forma sustentável a exploração desse recurso nesta reserva.

Histological validation of morphochromatically-defined gonadal maturation stages of green abalone (Haliotis fulgens) Philippi,1845 and pink abalone (Haliotis corrugata) Wood, 1828 / Validación histológica de las fases morfocromáticas de maduración gonádica del abulón azul (Haliotis fulgens) Philippi, 1845 y del abulón amarillo (Haliotis corrugata) Wood, 1828

Identifying the maturity stage of specimens is essential for the determination of the spawning season, which in turn facilitates the formulation of adequate fisheries management measures for the sustainable use of sea resources, such as abalone. This study aims to validate, based on histological evidence, a gonad maturation scale that encompasses four morphochromatically-defined stages (developing, maturity, spawning and resting) for females and males, plus an additional stage for reproductively inactive (undifferentiated) specimens, to be used as an identification key. Given the similarity between Haliotis fulgens and Haliotis corrugata as to their morphochromatic features, the gonadal maturation scale can be used for both species.

La determinación de la fase de madurez es importante para identificar la temporada de desove y permitir establecer medidas de manejo pesquero para el aprovechamiento responsable de los recursos como el abulón. El presente trabajo valida histológicamente una escala de maduración gonádica a manera de guía de identificación, que consiste de cuatro fases morfocromáticas para hembras y machos (desarrollo, madurez, desove y reposo), y un estadio para los organismos reproductivamente inactivos (indiferenciado). Dada la similitud entre las características morfocromáticas de Haliotis fulgens y Haliotis corrugata, la escala de maduración gonádica puede ser utilizada indistintamente.

Gametogenesis and weight change of body organs of the sea cucumber Holothuria (Halodeima) grisea (Aspidochirotida: Holothuriidae) in Southern Brazil / Aspectos reproductivos y la relación entre los órganos y la gametogénesis en Holothuria (Halodeima) grisea (Echinodermata: Holothuroidea)

Abstract The sea cucumber Holothuria (Halodeima) grisea is a widely distributed and economically important species that has been harvested in Brazil for several years, where there are no studies on its reproduction. We studied a population near Guaratuba Bay in Southern Brazil. Four sampling campaigns were made, in February, April, June and October 2008. We examined the macroscopic and microscopic features of the gonads to describe the gametogenesis. In addition, we analyzed the weight change of body organs. A total of 94 individuals were examined and no evidence of external sexual dimorphism was found. In April there were more males than females. Biometrically the body wall and gonads are the most important organs. The body wall increases in the June and the gonads during October and February; there might be an exchange of energy between these organs. Mature gonads are elongated and thick (red in females, cream in males). There were mature individuals year round, with an increase of sexual activity in February when oocyte mature diameter ranges from 70 to 160 µm. Spawning was in winter (June). Maturation period and body component variations were similar between sexes. Rev. Biol. Trop. 63 (Suppl. 2): 285-296. Epub 2015 June 01.

Resumen El pepino de mar Holothuria (Halodeima) grisea es una especie ampliamente distribuida y económicamente importante que se ha recolectado en Brasil desde hace varios años. No hay estudios previos realizados sobre la reproducción de esta especie en Brasil. Además, son aún poco conocidos los aspectos bio-ecológicos de esta especie. En este estudio, se investigaron algunos aspectos de la reproducción del pepino de mar Holothuria (Halodeima) grisea en una población cerca de la bahía de Guaratuba en el sur de Brasil. Se hicieron cuatro salidas de muestreo, en febrero, abril, junio y octubre de 2008, abarcando las cuatro estaciones. Examinamos las características macroscópicas y microscópicas de las gónadas para describir la gametogénesis, adicionalmente, se analizó el cambio de peso de cada componente de los órganos del cuerpo (pared corporal, gónadas, sistema haemal, tracto digestivo y árbol respiratorio). Se examinó un total de 94 individuos y no se encontraron evidencias de dimorfismo sexual externo. Los resultados del análisis estadístico de la prueba x² rechazan la hipótesis nula (H0) con una relación de sexos igual a 1, sin embargo, el análisis de cada mes, esta diferencia de género se observó sólo en el mes de abril, cuando el número de los males es mucho mayor que la de las hembras. Las medidas biométricas mostraron que la pared del cuerpo y las gónadas son los órganos más importantes, con aumentos de la pared corporal en el junio y de las gónadas durante octubre y febrero, que pueden indicar que hay un intercambio de energía entre estos órganos. Macroscópicamente, las gónadas maduras muestran túbulos largos, gruesos y ramificados siendo que las hembras presentan coloración rojiza e los machos tonos de crema. Sin embargo, durante el crecimiento y agotado, no se observaron diferencias morfológicas macroscópicas entre los sexos. Microscópicamente, se observó la presencia constante de individuos maduros entre meses, con un aumento de la actividad sexual en febrero, cuando los ovocitos maduros tuvieron un diámetro oscila entre 70 a 160 μ. El período de desove ocurrió en los meses de invierno (junio). El periodo de maduración y la variación del cuerpo de los componentes fueron similares entre los sexos. La similitud en las demandas metabólicas de la población podría estar confirmando una estrategia para maximizar la sincronía reproductiva.

The reproductive cycle of the sea urchin Lytechinus variegatus (Echinodermata: Echinoidea) in southern Brazil / Ciclo reproductive de Lytechinus variegatus (Lamarck, 1819) (Echinodermata: Echinoidea) en el sur de Brasil

Abstract Lytechinus variegatus (Lamarck) is a common echinoid found on the Atlantic coast of America from North Carolina to southern Brazil and their populations inhabit sub littoral shallow-water environments. This research examined some aspects of reproduction in the southern limit of distribution of the species. A total of 86 adult individuals of L. variegatus (50.8 to 77.0 mm test diameter) were manually collected from September 2000 to September 2001 along the unconsolidated bottoms at the eurihaline sector of Paranaguá Bay (48° 19' W - 25° 35' S) for histological characterization of gametogenesis, sex ratio and gonadal index (GI) evaluation. This population showed a synchronicity in maturation and spawning events (autumn and winter respectively), with a 1:1 sex ratio (χ2 = 2.57, df = 7, p < 0.05). The GI increase was associated with storage of nutritional resources periods (resting stages and proliferation) that occurred between late winter and spring. Biometric analyzes indicated a greater investment in size and/or quantity of gametes between late spring and summer, when it was possible to observe mature sperm occupying on average 63.9 % of the follicular lumen and oocytes reaching values of 70.0 to 75.0 μm. Mature oocyte mean size is the highest diameter of those developed by other regular echinoids in the same latitude. However, the average diameter of mature oocytes of L. variegatus in the southern limit of its distribution was lower than the values recorded for the northern hemisphere. Rev. Biol. Trop. 63 (Suppl. 2): 243-250. Epub 2015 June 01.

Resumen Lytechinus variegatus (Lamarck) es un equinoide común en la costa atlántica de América, desde Carolina del Norte, Estados Unidos, al sur del Brasil y sus poblaciones habitan ambientes sublitorales de aguas someras. Este trabajo examina algunos aspectos de la reproducción en el límite sur de distribución de la especie. Un total de 86 individuos adultos (50.8 a 77.0 mm de diámetro de testa) fueron colectados manualmente de septiembre de 2000 a setiembre de 2001, en fondos blandos del sector eurihalino de la bahía de Paranaguá (48° 19' W - 25° 35' S), para caracterización histológica, proporción de sexos y evaluación del índice gonadal (IG). La población exhibió sincronización en los eventos de maduración y liberación de gametos (otoño e invierno, respectivamente), con una proporción de sexos de 1:1 (χ2 = 2.57, df = 7, p < 0.05). El aumento del IG estuvo asociado a periodos de acumulación de recursos nutricionales (estadios de reposo y proliferación) que ocurrieron entre el final del invierno y el verano. Análisis biométricos indican una gran inversión en tamaño y cantidad de gametos entre final de primavera y verano, cuando es posible observar gametos maduros ocupando, en promedio 63.9 % del lumen folicular, y ovocitos alcanzando diámetros de 70 a 75 μm. El tamaño medio de los ovocitos maduros es el mayor entre los equinodermos regulares de la misma latitud. Sin embargo, el tamaño medio del diámetro de los ovocitos de L. variegatus en su límite sur de distribución es menor que los valores registrados para el hemisferio norte. Llegamos a la conclusión de que a través de su distribuición geográfica extensa, los factores ambientales locales modulan el ritmo y la magnitud de la reproducción en poblaciones de este equinodermo.

Induced reproduction in a migratory teleost species by water level drawdown

Captive reproduction is one of the problems faced in aquaculture requiring the manipulation of environmental factors and/or hormonal treatment. Thus, we seek to verify experimentally which gonadal changes were present in mature individuals of Astyanax altiparanae arising from decreased water level. Collections were made every four hours, initiated four hours before and finished 28 hours after stimulation, at the Fish Farming Station of Companhia Energética de São Paulo, São Paulo, Brazil. The gonads were analyzed by light microscopy. The females had ovaries in the spawning capable phase until 12h; in 16h, in a more advanced stage of spawning capable phase; and, from 20h, in the regressing phase. Males had testes in the spawning capable phase until 8h; in 12h, in a more advanced stage of spawning capable phase; and, from 16h, the return to the spawning capable phase. The morphological description was corroborated by the proportion of cell classes. Females presented variation on the gonadosomatic index, but it was not found an emptying of the gonad for neither sex. The process of inducing reproduction with water level drawdown was considered satisfactory, since both sexes presented a reduction in the number of mature gametes at the end of the sample period.

Reprodução em cativeiro é um dos problemas enfrentados na aquicultura exigindo a manipulação de fatores ambientais e/ou tratamento hormonal. Assim, verificou-se experimentalmente as alterações gonadais presentes em indivíduos adultos de Astyanax altiparanae decorrentes da diminuição do nível da água. As coletas foram realizadas a cada quatro horas, iniciadas quatro horas antes e encerradas 28 horas após a estimulação, na Estação de Piscicultura da Companhia Energética de São Paulo, São Paulo, Brasil. As gônadas foram analisadas por microscopia de luz. As fêmeas apresentaram ovários na fase de apto à reprodução até 12h; em 16h, um estágio mais avançado desta fase; e, a partir das 20h, na fase de regressão. Os machos tiveram os testículos em fase de apto à reprodução até 8h; em 12h, um estágio mais avançado desta fase; e, a partir das 16h, o retorno à fase de apto à reprodução. A descrição morfológica foi corroborada pela proporção das classes celulares. As fêmeas apresentaram variação no índice gonadossomático, mas não foi estabelecido o esvaziamento das gônadas para nenhum dos sexos. O processo utilizado para a indução à reprodução foi considerado satisfatório, uma vez que ambos os sexos apresentaram redução no número de gametas maduros no final do período de amostragem.

Artificial gametes from stem cells / 대한생식의학회지

The generation of artificial gametes is a real challenge for the scientific community today. In vitro development of human eggs and sperm will pave the way for the understanding of the complex process of human gametogenesis and will provide with human gametes for the study of infertility and the onset of some inherited disorders. However, the great promise of artificial gametes resides in their future application on reproductive treatments for all these people wishing to have genetically related children and for which gamete donation is now their unique option of parenthood. This is the case of infertile patients devoid of suitable gametes, same sex couples, singles and those fertile couples in a high risk of transmitting serious diseases to their progeny. In the search of the best method to obtain artificial gametes, many researchers have successfully obtained human germ cell-like cells from stem cells at different stages of differentiation. In the near future, this field will evolve to new methods providing not only viable but also functional and safe artificial germ cells. These artificial sperm and eggs should be able to recapitulate all the genetic and epigenetic processes needed for the correct gametogenesis, fertilization and embryogenesis leading to the birth of a healthy and fertile newborn.

Rhox in mammalian reproduction and development / 대한생식의학회지

Homeobox genes play essential roles in embryonic development and reproduction. Recently, a large cluster of homeobox genes, reproductive homeobox genes on the X chromosome (Rhox) genes, was discovered as three gene clusters, alpha, beta, and gamma in mice. It was found that Rhox genes were selectively expressed in reproduction-associated tissues, such as those of the testes, epididymis, ovaries, and placenta. Hence, it was proposed that Rhox genes are important for regulating various reproductive features, especially gametogenesis in male as well as in female mammals. It was first determined that 12 Rhox genes are clustered into alpha (Rhox1-4), beta (Rhox5-9), and gamma (Rhox10-12) subclusters, and recently Rhox13 has also been found. At present, 33 Rhox genes have been identified in the mouse genome, 11 in the rat, and three in the human. Rhox genes are also responsible for embryonic development, with considerable amounts of Rhox expression in trophoblasts, placenta tissue, embryonic stem cells, and primordial germ cells. In this article we summarized the current understanding of Rhox family genes involved in reproduction and embryonic development and elucidated a previously unreported cell-specific expression in ovarian cells.

Variación lipídica en los ovocitos de la medusa Stomolophus meleagris (Scyphozoa: Rhizostomeae), durante el desarrollo gonádico, en la laguna Las Guásimas, Sonora, México

Lipid variation in oocytes of the jellyfish Stomolophus meleagris (Scyphozoa: Rhizostomeae) from Las Guasimas Lagoon, Mexico, during gonadal development. The jellyfish Stomolophus meleagris has potential for commercial exploitation but there is little information on their reproductive biology. This paper seeks to evaluate some biochemical and demographic characteristics of the species. Samples were taken monthly during 2005 and 2006. Jellyfish collected in 2005 were used to describe the characteristics and quantity of oocyte triglycerides and phospholipids with the Sudan black technique, and to ascertain the degree of gonadal development and sex ratio by the hematoxylin-eosin technique. The 2006 jellyfish were used to determine the size at first maturity and protein and total lipids contents. Four stages of development in both sexes were determined, with a continuous gamete development. The highest percentage of mature organisms was recorded in April. The proportion of sexes was 0.7:1.3. We found higher concentrations of triglycerides than phospholipids in the cytoplasm. There was a positive correlation between triglycerides and the diameter of the oocyte. The size at first maturity for both sexes was 105mm. The highest protein and lipids contents were obtained in April and March respectively. Rev. Biol. Trop. 58 (1): 119-130. Epub 2010 March 01.

La medusa S. meleagris, ha mostrado potencial de explotación pero hay escasa información sobre su biología reproductiva. El presente trabajo pretende conocer el contenido de los triglicéridos y fosfolípidos en los ovocitos durante el desarrollo gonadal, así como la proporción de sexos, talla de primera madurez y la concentración de proteínas y lípidos totales en la medusa. Se realizaron muestreos mensuales durante 2005 y 2006. A las medusas recolectadas en 2005, se les aplicó la técnica del sudán negro, para describir las características del ovocito y la cantidad triglicéridos y fosfolípidos y la técnica de hematoxilina-eosina para conocer el grado de desarrollo gonádico y la proporción de sexos. Las medusas del 2006 se emplearon para determinar la talla de primera madurez y el contenido de proteínas y lípidos totales. Se observaron cuatro fases de desarrollo en ambos sexos, con un desarrollo gamético continúo. El mayor porcentaje de organismos maduros se registró en abril. La proporción de sexos fue de 0.7:1.3. Se encontró mayor concentración de triglicéridos que de fosfolípidos en el citoplasma. Se obtuvo una correlación positiva entre triglicéridos y el diámetro del ovocito. La talla de primera madurez para ambos sexos fue de 105 mm. El mayor contenido de proteínas se obtuvo en abril y para lípidos en marzo.

Estudio citológico en poblaciones diploides y poliploides del género tripsacum / CYTOLOGICAL STUDY IN DIPLOID AND POLIPOID POPULATIONS OF THE Tripsacum GENUS / ESTUDO CITOLÓGICO EM POPULAÇÕES DIPLÓIDES E POLIPLÓIDES DO GÊNERO Tripsacum

El género Tripsacum (Poaceae) tiene afinidad filogenética con el maíz y se distribuye ampliamente en América. El número básico de cromosomas es x=18 y existen poblaciones naturales desde diploides (2n=2x=36) hasta hexaploides (2n=6x=108). Las plantas de este género se reproducen de manera sexual y asexual y, en poliploides, ocurre la apomixis. Se realizó un estudio citológico en plantas con diferente nivel de ploidía. En espigas se hizo análisis de la meiosis, y de semillas se obtuvieron plántulas a las cuales se determinó el número cromosómico en ápices radicales y por cuantificación de ADN mediante citometría de flujo. Se encontraron poblaciones constituidas únicamente por triploides o tetraploides, y otras que contienen una mezcla de diploides hasta hexaploides. En diacinesis, los cromosomas de los diploides se asocian en bivalentes; en los triploides se forman univalentes, bivalentes y trivalentes; mientras que en tetraploides en univalentes, bivalentes, trivalentes y cuadrivalentes. En profase II, los diploides forman, en alta frecuencia, grupos cromosómicos segregantes de 18; los triploides desde 21 hasta 33; y los tetraploides desde 32 hasta 38. El número de cromosomas en progenies de plantas diploides fue 2x=36 y 3x=54; de triploides, 3x=54, 4x=72, 5x=90 y 6x=108; y de tetraploides, 4x=72, 5x=90 y 6x=108. Los resultados indican que los diploides tienen un origen sexual y que los triploides y tetraploides posiblemente sean apomícticos facultativos.

The Tripsacum (Poaceae) genus has phylogenetic affinity with maize and is widely distributed in America. The basic number of chromosomes is x=18, and there are natural populations ranging from diploids (2n=2x=36) to hexaploids (2n=6x=108). The plants of this genus reproduce sexually and asexually and, in polyploids, apomixis occurs. A cytological study was conducted in plants with different ploidy level. Analysis of meiosis was made in tassels, and seedlings were obtained whose chromosomal number was determined in root tips and by DNA quantification using flow cytometry. Populations made up only of triploids or tetraploids were found, and others containing a mixture from diploids to hexaploids. During diakinesis, diploid chromosomes associate in bivalents; in triploids, univalents, bivalents, and trivalents are formed; and in tetraploids, univalents, bivalents, trivalents, and quadrivalents are formed. In prophase II, the diploids form with high frequencies segregating chromosomal groups of 18; the triploids, groups from 21 to 33; and tetraploids, from 32 to 38. The chromosomal number in progenies of diploid plants was 2x=36 and 3x=54; of triploids 3x=54, 4x=72, 5x=90, and 6x=108; and from tetraploids, 4x=72, 5x=90, and 6x=108. Results indicate that the diploid individuals have sexual origin and the triploids and tetraploids may be apomictic.

O gênero Tripsacum (Poaceae) tem afinidade filogenética com o milho e se distribui amplamente na América. O número básico de cromossomas é x=18 e existem populações naturais desde diplóides (2n=2x=36) até hexaplóides (2n=6x=108). As plantas deste gênero se reproduzem de maneira sexual e asexual e, em poliplóides, ocorre a apomixia. Realizou-se um estudo citológico em plantas com diferente nível de ploidia. Foi realizada análise em espigas da meiose e das sementes foram obtidas plântulas nas quais se determinou o número cromossômico em ápices radicais e por quantificação de DNA mediante citometria de fluxo. Encontraram-se populações constituídas unicamente por triplóides ou tetraplóides, e outras que contêm uma mistura de diplóides até hexaplóides. Em diacinese, os cromossomas dos diplóides se associam em bivalentes; nos triplóides se formam monovalentes, bivalentes e trivalentes; enquanto que em tetraplóides em monovalentes, bivalentes, trivalentes e tetravalentes. Na profase II, os diplóides formam, em alta frequência, grupos cromossômicos segregantes de 18; os triplóides desde 21 até 33; e os tetraplóides desde 32 até 38. O número de cromossomas em progênies de plantas diplóides foi 2x=36 e 3x=54; de triplóides, 3x=54, 4x=72, 5x=90 e 6x=108; e de tetraplóides, 4x=72, 5x=90 e 6x=108. Os resultados indicam que os diplóides têm uma origem sexual e que os triplóides e tetraplóides possívelmente sejam apomícticos facultativos.

Identification of a Novel Gene by EST Clustering and its Expression in Mouse Ovary and Testis / 대한불임학회지

OBJECTIVE: Identification of the regulatory mechanism for arrest and initiation of primordial follicular growth is crucial for female fertility. Previously, we found 15 expressed sequence tags (ESTs) that were specifically abundant in the day-5-subtracted cDNA library and that the B357 clone was novel. The present study was conducted to obtain the whole sequence of the novel gene including B357 and to characterize its mRNA and protein expression in mouse ovary and testis. METHODS: The extended sequence of the 2,965-bp cDNA fragment for the clone B357 was named 5-day-ovary-specific gene-1 (5DOS1) and submitted to GenBank (accession number AY751521). Expression of 5DOS1 was characterized in both female and male gonads at various developmental stages by Northern blotting, real-time RT-PCR, in situ hybridization, Western blotting, and immunohistochemistry. RESULTS: The 5DOS1 transcript was highly expressed in the adult testis, brain, and muscle as compared to the other tissues. In the ovary, the 5DOS1 transcript was detected in all oocytes from primordial to antral follicles, and highly expressed at day 5 after birth and decreased thereafter. In contrast, expression of 5DOS1 showed a gradual increase during testicular development and its expression was limited to various stages of male germ cells except spermatogonia. CONCLUSIONS: This is the first report on the expression and characterization of the 5DOS1 gene in the mouse gonads. Further functional analysis of the 5DOS1 protein will be required to predict its role in gametogenesis.

The Novel Noncoding Small RNA: Piwi-interacting RNA(piRNA) / 生物化学与生物物理进展

piRNA is a novel class of small single strand RNA that were recently isolated from testes of the mammals. These RNAs are bigger (26～31 nt) than most previously described small RNAs (21～23 nt) and are associated with Piwi-subfamily members of the Argonaute protein family.

CYTOLOGICAL EFFECT OF GOSSYPOL ON RAT GAMETOGENESIS AND SPERMATOZOA / 解剖学报

Induction of possible male sterility in laboratory rats by gossypol was examined by microscopic observations on sperm motility, sperm morphology following silver staining, and meiosis. The rats were force-fed with gossypol acetate once with 400mg/kg body weight. In a span of 2-5 weeks post-feeding, a marked reduction of sperm motility was observed with a concurrent increase of abnormal spermatozoa Silver staining of the spermatozoa showed various tail abnormalities, including disrupted connecting piece, bent tails, looped tails, and cracked midpiece, Sperm head structure appeared to be not affected. Beginning 6 weeks post-feeding, there was a complete recovery. Short-term in vitro experiments showed similar but weaker response. In all samples, histologieal sections and cytogenetic preparations of testes revealed no abnormalities in the activity and normally of meiotic divisions. In animals 2-4 weeks after feeding with gossypol, no argentophilic accessary structures in developing mammalian spermatids were observed.