Pattern and Mechanism of Calcium Mobilization During Embryonic Development in a Viviparous Snake, <em>Virginia striatula</em>.

• Main Author: Fregoso, Santiago
• Format: Others
• Published: Digital Commons @ East Tennessee State University 2010
• Subjects: calcium; oviparity; placentotrophy; squamates; viviparity; Cell and Developmental Biology; Developmental Biology; Life Sciences
• Online Access: https://dc.etsu.edu/etd/1712; https://dc.etsu.edu/cgi/viewcontent.cgi?article=3067&amp;context=etd

Yolk supplies the majority of embryonic calcium in snakes. Oviparous and viviparous snakes also receive calcium late in development from the eggshell and placenta, respectively. The pattern and mechanism of calcium transport are partly understood for oviparous snakes. I studied a viviparous snake, Virginia striatula, to determine the pattern of embryonic calcium accumulation as well as the ontogenetic expression of calcium transporting proteins in extraembryonic tissues. The pattern of embryonic calcium uptake of V. striatula occurs late in development, during the phase of highest embryonic growth. Calbindin-D28k, Ca2+ ATPase, and carbonic anhydrase II are expressed in chorioallantoic membrane, while yolk sac only expresses calbindin-D28k, coincident with the timing of calcium transport in embryos of V. striatula. Thus, the pattern of embryonic calcium accumulation in V. striatula is similar to that of oviparous snakes. Although calbindin-D28k and Ca2+ ATPase are likely active in embryonic calcium transport, the role of carbonic anhydrase II remains less clear.