Democratic front runner Joe Biden on Monday appealed to a billionaire Republican donor for fundraising help in his presidential campaign. But the financier, Trump-supporting New York supermarket magnate John Catsimatidis, declined. Biden spoke to Catsimatidis, who has an estimated net worth of $3.1 billion, for about 10 minutes at a fundraiser held at the New York home of short seller Jim Chanos, according to the businessman.