Esther Uría-Galicia

Evaluation of kidney injury biomarkers in rat amniotic fluid after gestational exposure to cadmium.

Cadmium is a well‐characterized nephrotoxic agent that is also capable of accumulating and diffusing across the placenta; however, only a few studies have addressed its effects over fetal kidneys and none of them has used a panel of sensitive and specific biomarkers for the detection of kidney injury. The goal of this study was to determine cadmium renal effects in rat fetuses by the quantification of early kidney injury biomarkers. Pregnant Wistar rats were exposed by inhalation to an isotonic saline solution or to CdCl2 solution (DDel=1.48 mg Cd kg−1 day−1) during gestational days (GD) 8–20. On GD 21, dams were euthanized and samples obtained. Kidney injury biomarkers were quantified in amniotic fluid samples and fetal kidneys were microscopically evaluated to search for histological alterations. Our results showed that cadmium exposure significantly raised albumin, osteopontin, vascular endothelial growth factor and tissue inhibitor of metalloproteinases‐1 levels in amniotic fluid, whereas it decreased creatinine. Clusterin, calbindin and IFN‐inducible protein 10 did not show any change. Accordingly, histological findings showed tubular damage and precipitations in the renal pelvis. In conclusion, gestational exposure to cadmium induces structural alterations in fetal renal tissue that can be detected by some kidney injury biomarkers in amniotic fluid samples. Copyright

Populations of the Butterfly Goodeid (Ameca splendens) in the Upper Rio Ameca Basin, Mexico

ABSTRACT The endangered endemic fish Ameca splendens was surveyed monthly from June 2001 to May 2002 at two sites in the upper Rio Ameca basin. Both populations demonstrated two annual reproduction peaks, with one in the spring season and the other in late fall. The condition and gonadosomatic index were higher in the population from the upstream pristine environment. Those fish in the pollution-stressed downstream region attained greater body length, longevity, and fecundity.

Ultrastructural and Histological Study of Oogenesis and Oocyte Degeneration in the PenshellAtrina maura(Bivalvia: Pinnidae)

Abstract The successive stages of oogenesis and the changes involved in the oocyte degeneration process in the penshell Atrina maura were examined using light and transmission electron microscopy. The ovarian maturation process is asynchronous, as oocytes at different developmental stages can be found simultaneously. Oocytes develop from oogonia and then undergo three distinct stages of oogenesis: previtellogenesis, vitellogenesis and postvitellogenesis with mature oocytes. Atrina maura displays a solitary oogenesis type, in which follicular cells become associated with oocytes from the earliest stages of development and seem to play an integral role in vitellogenesis. The cytoplasm of vitellogenic oocytes contains numerous whorls of rough endoplasmic reticulum and Golgi bodies, suggesting that auto-synthetic vitellogenesis may occur in this species. In addition, the degeneration process of postvitellogenic oocytes triggered by a seasonal increase in water temperature (> 25°C) is described.

Ultrastructure of Sperm Development and Mature Sperm Morphology in Spondylus calcifer and S. Princeps (Bivalvia: Spondylidae)

ABSTRACT The entire spermatogenesis process and the presence of accessory cells in sperm development in Spondylus princeps Broderip, 1833, and S. calcifer Carpenter, 1857, were described for the first time. Spermatogenesis in both species showed similar anatomical and ultrastructural features. The testis contained amoeboid somatic cells inside the acini, frequently associated with developing gametes. Overall, spermatogenesis followed the typical pattern reported for other bivalve species, except for a few specific details. In S. princeps, intercellular bridges between spermatogonia, as well as one spermatocyte with seven mitochondria were observed. Both species had mature sperm of the ect-aquasperm type, consisting of a head, which contains a spherical-pyriform nucleus and a conical acrosome bounded by two regions of different density, four spherical mitochondria and two centrioles in the middle piece; the flagellum showed a standard 9 + 2 microtubule arrangement.

Biología Reproductiva de Mytilopsis leucophaeata (Conrad, 1831) (Bivalvia: Dreissenidae) de la Laguna de Tampamachoco, Túxpam-Veracruz

Se caracterizo el ciclo reproductivo de Mytilopsis leucophaeata (Conrad, 1831) en organismos colectados mensualmente durante un ciclo anual en la laguna de Tampamachoco, Tuxpam, Veracruz, que se ubica en la costa del Golfo de Mexico en la Region Terrestre Prioritaria (RTP-103) de CONABIO considerada sitio RAMSAR 1602 en Mexico. Los resultados histologicos indican que M. leucophaeata presenta cuatro etapas gametogenicas: gametogenesis, madurez, desove total para hembras y expulsion parcial para machos. Uno de los principales factores que influyen en el desove sincronico de gametos tanto en machos como en hembras es la salinidad, en los meses de enero a marzo.

Descripción Histológica de la Cámara Incubatriz de Moina hutchinsoni (Brem, 1937)

Los cladoceros son partenogeneticos por lo que la mayor parte del ano, las poblaciones consisten enteramente de hembras que se reproducen asexualmente, en ellas el ovario se comunica por medio de un oviducto, con la camara incubatriz, la cual se localiza en el margen interno posterior del caparazon, cerca del corazon y antes del intestino. Los huevos provenientes de los oviductos se depositan en la camara y se incuban hasta terminar el desarrollo embrionario. Se considera que Moina presenta un desarrollo postembrionario directo, porque los organismos juveniles o neonatos, salen completamente formados e independientes durante la muda. En la reproduccion asexual la camara contiene a las diferentes etapas del desarrollo embrionario llamadas; ovocito, huevo y embrion. En la etapa sexual o gamogenetica la camara contiene un efipio con dos huevos. La camara incubatriz histologicamente esta conformada por un epitelio plano simple, que descansa sobre una membrana basal evidente, la cual se continua con el tejido conjuntivo laxo, despues del cual se encuentra el caparazon. En el interior de la camara se identificaron los ovocitos, huevos y algunas etapas del desarrollo embrionario, en cortes semifinos y finos por microscopia optica y de transmision, respectivamente.