Landry's Restaurants Inc., whose operations include Rainforest Cafe and The Crab House, is buying the Golden Nugget hotel-casino in downtown Las Vegas, a first step in a strategy to get a slice of the lucrative gambling business and expand its profit pipeline. Landry's shares surged more than 8 percent on the news. Houston-based Landry's announced Friday it struck a deal with Poster Financial Group Inc., owners of the Golden Nugget, under which it would pay $140 million in cash and assume $155 million in debt for the Golden Nugget. The Golden Nugget Las Vegas is considered the jewel of a faded downtown with 1,907 hotel rooms and 2,800 employees. Built in 1946, it's the largest of the 14 hotel-casinos in the downtown area. Landry's owns and operates more than 300 restaurants, and the brands also include Landry's Seafood House, Joe's Crab Shack, Willie G's Seafood & Steakhouse and The Chart House.