Congress Abstracts - Society for Developmental Biology

truncated form of Oct60 disturbed PGC migration within the endoderm toward the genital ridge at tailbud stage. These results
suggest that Oct60 plays the important role in PGC formation.
Program/Abstract # 175
Paracrine signalling as intraovarian regulator during Xenopus laevis oogenesis
Serrano, Maria de los Angeles; Luque, Melchor Emilio; Sánchez, Sara Serafina (INSIBIO - CONICET, Argentina)
Oogenesis in vertebrates has been well characterized as the result of a harmonic regulation between different signaling systems such
as endocrine and juxtacrine . Throughout the last decade, paracrine factors like the bone morphogenetic proteins (BMPs) have been
identified as fundamental for the correct progression of oogenesis. In this sense, BMPs have become integrated into the whole
oogenesis process as intraovarian regulators. Not much is known about paracrine regulation during oogenesis in oviparous
vertebrates, where the process has the additional complexity of the delicately controlled vitellogenesis. This is characterized by
hepatic production of the glycoprotein vitellogenin (VTG) that is transported via the bloodstream to the ovary where it is incorporated
by oocytes. It is known that in the amphibian ovary the three different stages previtellogenesis, vitellogenesis and maturation are
regulated by endocrine and juxtacrine, mediated by gap junction, signaling. In the present study, we examine the participation of BMP
factors during Xenopus laevis previtellogenesis and vitellogenesis. To analyse the participation of paracrine signaling, we first
determined the gene expression of the different members of the BMP family through oogenesis. To determine a functional role of the
paracrine factors and a possible interaction with endocrine and juxtacrine signaling, we performed different assays with the BMP
pathway inhibitor LDN-193189. The results showed that BMPs are implicated in Xenopus laevis oogenesis, a complex process
coordinated by a cross-talk between the molecules of different signaling pathways.
Program/Abstract # 176
Effects of glyphosate on structure and SF-1 expression in ovaries of zebrafish Danio rerio
Ammar, Dib; Armiliato, Neide; Nazari, Evelise; Nezzi, Luciane; Straliotto, Marcos; Müller, Yara (Universidade Federal de Santa
Catarina, Florianópolis, Brazil)
Glyphosate is non-selective herbicide and highly soluble in water, and when applied in terrestrial systems, it percolates and infiltrates
into the soil, eventually reaching the aquatic community and consequently affecting non-target organisms. Aiming to better understand
the toxicity of glyphosate to female germ cells of the zebrafish Danio rerio , this study evaluated the structure, ultrastructure and
expression of steroidogenic factor 1 (SF-1) in ovaries exposed to 65 μg/L of glyphosate [N-(phosphonomethyl) glycine] for 15 days.
No morphological changes were recognized in the ovaries of exposed and non-exposed females. However, a significant increase in the
diameter of previtellogenic and vitellogenic oocytes was observed after exposure to glyphosate. When we analyzed the ovarian
ultrastructure, we observed, in the cortical regions of the oocytes, the presence of concentric membranes, appearing as myelin-like
structures, associated with the external membranes of mitochondria, and also with the yolk granules. Also, a more significant
immunolocalization of SF-1 was found in cortical yolk granules of D.rerio , after exposure to 65 μg/L of glyphosate. The subtle
noxious effects of glyphosate on oocytes demonstrated here are a serious concern for fish reproduction and must be taken into
account. These results contribute to the understanding of glyphosate toxicity to non-target organisms, showing subcellular and
molecular impairments that affect the reproduction of female fish.
Program/Abstract # 177
Dynamic expression patterns of RaVasa during oogenesis and early embryonic development in Rhynchosciara americana
Rezende-Teixeira, Paula; Machado-Santelli, Glaucia (Universidade de São Paulo, Brazil)
The Dipteran Rhynchosciara americana, a native Brazilian insect, provides an interesting opportunity to study a different model of
insect oogenesis and embryogenesis. The ovarian development in R.americana presents unique characteristics: the synchronic
development of the ovarian follicles and only one giant nurse cell connected with the oocyte through ring canal. The last mitotic
division of undifferentiated germ cells occurs early in its larval life. Each oogonium gives rise to two cells, with different fates: the
oocyte and the nurse cell.
The initial analysis of sequences of a cDNA library constructed with poli A+ RNA of ovary from different ages of Rhynchosciara
americana larvae showed messages related to different molecular functions and biological process. In the present work we isolated a
Rhynchosciara homolog of vasa (RaVasa) and examined the spatial and temporal expression of RaVasa mRNA during the gonad and
embryonic development. RaVasa mRNAs accumulated in ovarian follicles of Rhynchosciara americana in young larva ovary and
adult fly ovary suggesting that RaVasa is maternally contributed to the Rhynchosciara americana eggs. Furthermore, the RaVasa
protein is localized to the posterior pole of the egg and then incorporated into pole cells and remained expressed in germ cells
throughout developmental stages. The molecular structure showed the presence of conserved domains and the RaVasa gene encodes
an ATP-dependent RNA helicase of the DEAD box protein family. This protein is specifically expressed in the germ cell lineage and
is required for multiple processes in the development and maintenance of primordial germ cells.
Program/Abstract # 178
A Transcriptome Analysis of Animal and Vegetal Half-Embryos of the Penaeid Shrimp Marsupenaeus japonicas
Hertzler, Philip Lamar (Central Michigan Univ, USA); Trewin, Carolyn; McWilliam, Sean; Sellars, Melony (CSIRO, Australia)
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