All that glitters "is" not gold /all that dogs bark at "are"

All that glitters "is" not gold /all that dogs bark at "are"not thieves.
All that glitters is not gold./All is not gold that glitters.闪光的并非都是金子.
All that dogs bark at are not thieves./All are not thieves that dogs bark at .狗吠者未必是贼.(勿以貌取人)
为什么么前一句谓语动词是"IS",而后一句的却是"ARE"?
glitters 应该是动词吧.闪光.
另外,英语中部分否定与全否定怎么区分?如果我要表达:发亮的都不是金子应该怎么说?