Australians Robin Warren and Barry Marshall receive the 2005 Nobel Prize in Physiology or Medicine. Their research bucked conventional wisdom, showing that a bacterium, not simply excess stomach acid, causes peptic ulcers. Also, it suggested that bacterium may be a major cause of stomach cancer. - NPR news
buck (verb)oppose [transitive] to oppose
something in a direct way:
He was a rebel who bucked the system (=opposed rules
or authority).
Unemployment in the area has bucked the trend by falling
over the last month.
-Longman
buck conventional wisdom - 挑战传统智慧、和传统智慧唱反调
这个短语已经是英语中固定的说法。所以如果你想把“挑战传统智慧”翻译成中文，没有必要翻译成,"challenge conventional/traditional wisdom"，说"buck conventional wisdom"就行了。
buck在美国口语中经常用作名词，等于"dollar"
Can you lend me 100 bucks? = Can you lend me 100 dollars?－你能借100美元给我么？