Biotech companies in the East Bay married up in 2005 - and exchanged dowries totaling nearly $10 billion - in a string of mergers and acquisitions that promise to shake up the local biotech landscape. Topping the most watched list is Novartis AG’s $5 billion bid for Emeryville’s Chiron Corp., the East Bay’s most prominent biopharmaceutical firm and one of the industry’s darlings. The deal, announced in October after the two wrangled over price for months, is expected to close in the first half of 2006.