The board of iPierian, the South San Francisco-based stem cell company with high-profile scientific founders from Harvard University and prominent financial backers that include GlaxoSmithKline, Kleiner Perkins Caufield & Byers, Google Ventures, and Biogen Idec, has terminated several members of the company’s senior executive team as part of a shift in strategy, Xconomy has learned. Michael Venuti, who was named CEO of Ipierian in July 2010, was fired by the board in late April of this year, and the company’s top executives in charge of finance, business development, and legal/intellectual property were dismissed within days, according to John Walker, Venuti’s predecessor as CEO of iPierian, and two other sources with knowledge of the situation.