ISTANBUL (Reuters) - Turkey is investigating an alleged plot to assassinate Ecumenical Patriarch Bartholomew, spiritual leader of the world's Orthodox Christians, and has stepped up security around the patriarchate in Istanbul, his spokesman said on Friday. Spokesman Dositheos Anagnostopoulos said the patriarch had not received any direct threats but had learned of the alleged plot from Turkish media, which was later confirmed to the patriarchate by Turkish police. ...