Today's Small-Cap Winners and Losers

Ambassadors International (AMIE) gained after the Newport Beach, Calif., travel and event services firm reached an agreement to acquire the assets of Delta Queen Steamboat Co.

The deal calls for Ambassadors Cruise Group, a unit of Ambassadors, to buy the three vessels and operating assets of Delta Queen for $3 million in cash and the assumption of about $9 million of customer deposits and around $35 million of debt.

Additionally, Delta Queen can get up to 100,000 Ambassadors shares if certain financial targets are met in the three years following the close of the transaction. Shares of Ambassadors gained $2.18, or 12.1%, to $20.15.

Williams Partners (WPZ) fell after the Tulsa, Okla., energy concern agreed to buy a 25.1% interest in Williams Cos.' (WMB ) Four Corners LLC division for $360 million.

Williams Partners said it will sell 7 million common units and use the proceeds from the sale, combined with proceeds from a $150 million private debt offering, to pay for the stake in Four Corners. Lehman Brothers and Citigroup are expected to underwrite the unit offering. Shares fell $1.25, or 3.8%, to $31.50.

Metallica Resources (MRB) sank after the Toronto-based gold and silver producer said regulators in Mexico renewed a previously imposed restriction on a blasting permit for the company's local unit MSX.

Metallica said MSX is working through political and legal channels to have the restriction lifted. The company believes the matter can be resolved within the next several weeks. Shares of Metallica fell 73 cents, or 20%, to $2.93.

PRA International (PRAI) rose on word the Reston, Va., contract research organization was upgraded by Goldman Sachs to outperform from in-line. Shares gained $1.79, or 7.4%, to $26.10.

Shares of Buca (BUCA) surged a day after the Minneapolis-based restaurant owner said same-store sales at its Buca di Beppo restaurants rose 5.6% for the first quarter compared with the same period last year. For the year-ago quarter, comp sales increased 6.7%. Buca was up 74 cents, or 15.6%, to $5.47.