GLOBAL MARKETS-Euro zone inflation turns negative, Brent oil below $50

* Euro zone inflation turns negative* Brent oil breaks below $50* Euro falls to 9-year lowBy Jamie McGeeverLONDON, Jan 7 (Reuters) - The euro hit a nine-year trough and bond yields in several euro zone countries reached record lows on Wednesday, as tumbling oil prices tipped inflation into negative territory for the first time since 2009, raising the prospect of outright deflation.Euro zone annual