TitleThe Nature of Exocytosis in the Yolk Trophoblastic Layer of Silver Arowana (Osteoglossum bicirrhosum) Juvenile, the Representative of Ancient Teleost Fishes
Publication TypeJournal Article
Year of Publication2009
AuthorsJaroszewska, M, Dabrowski, K
JournalThe Anatomical Record
Volume292
Pagination1745 - 1755
Date Published2009
Abstract

We have chosen the silver arowana (Osteoglossum bicirrhosum), a representative of the most ancient teleost family Osteoglossidae, to address the question of yolk nutrients utilization. Silver arowana have particularly large eggs (1–1.5 cm of diameter) and a unique morphology of the yolk. We present evidence that the yolk cytoplasmic zone (ycz) in the ‘‘yolk sac juveniles’’ is a very complex structure involved in sequential processes of yolk hydrolysis, lipoprotein particles synthesis, their transport, and exocytosis.Vacuoles filled with yolk granules in different stages of digestion move from the vitellolysis zone through the ycz to be emptied into the microvillar interspace in the process of exocytosis. The area of the ycz with the abundance of the mitochondria must play an important role in providing energy for both the transport of vacuoles and the release of their contents. Therefore, we postulate that the function of yolk syncytial layer (ysl) as the‘‘early embryonic patterning center’’ transforms in fish larvae or yolksac juveniles into a predominantly specialized role as the yolk trophoblastic layer ( ytl) involved in yolk nutrients utilization. In addition to discovering the mechanism of transformation of the ysl function into ytl function, we suggest that the machinery involved in nutrient mobilization and exocytosis in yolk of arowana yolksac juveniles can be very attractive system for studies of regulatory processes in almost all secretory pathways in animal cells. 

URLhttp://onlinelibrary.wiley.com/doi/10.1002/ar.20996/epdf
Notice of Publication Number

NOP 09-A20 (English)