Mubadala Investment Co just planted its flag in the U.S. natural gas scene, marking its first real foray into the Lower 48's upstream and LNG ambitions. The Abu Dhabi wealth fund's energy arm has snapped up a 24% stake in SoTex HoldCo LLC-operator of a shale gas field and backer of an LNG terminal in Louisiana. Translation: Mubadala's not just dipping a toe; it's cannonballing into America's gas game. The move comes hot on the heels of the UAE's $1.4 trillion promise to the U.S.-a decade-long investment...