Shares of Life Technologies Corp. climbed in premarket trading Tuesday after a report surfaced about companies interested in acquiring the life science and medical research instrument maker.

The Wall Street Journal said that investment manager KKR & Co. is thinking about pairing up with other private equity firms to pursue Life Technologies. The report, citing anonymous sources, also said Danaher Corp. and Thermo Fisher Scientific Inc. are considering bids.

A KKR spokesman said in an email that the company does not respond to market speculation. The other companies did not immediately respond to requests seeking comment from The Associated Press.

Life Technologies offers biological technology including DNA synthesis, protein analysis, stem cell tools and chemicals used in forensics and food safety. The Carlsbad, Calif., company was formed in November 2008 through the combination of Invitrogen Corp. and Applied Biosystems Inc.

The company said in January that it had retained Deutsche Bank Securities and Moelis & Co. to help conduct a strategic review of its business, but it had not decided on a course of action. Companies sometimes hire bankers to find ways to unlock shareholder value, which can result in the spinoff of a division or even the sale of the whole company.

The price of Life Technologies shares topped $65 and reached a new all-time high after that announcement, but the shares have since retreated.

They rose $2.81, or 4.6 percent, to $63.90 in trading 30 minutes ahead of the market opening on Tuesday.