Instituform Technologies ( INSU) was plunging 22.8% on two pieces of news. The Chesterfield, Mo., construction company was downgraded to sell from hold by Stifel Nicolaus after predicting lower 2007 earnings year over year, citing a lack of growth in the general sewer-pipeline-rehabilitation market. The company will also take a $21 million pretax charge (or 48 cents a share after taxes) in order to exit the tunneling business, most of which will be incurred in the first half of the year. The liquidation value of all related assets is estimated at $20 million, at most. Shares slid $5.90 to $20.00. CuraGen ( CRGN) tumbled on word Roche will buy its majority-owned unit 454 Life Sciences. The Branford, Conn., biotech will receive $140 million in cash and up to some $14.9 million in stock options, which pans out at roughly $85 million on a fully diluted basis. The deal should close in the second quarter. Shares were off 77 cents, or 20.1%, to $3.07.