Characterization of free endogenous sphingoid bases in the golden apple snail Pomacea canaliculata : involvement in snail development and nutrient limitation - Qiong Yang; Xiwang Li; Xianwen Lin; Ying Zhou; Jingqun Yuan; Huadi Wang; Jiaan Cheng; Cungui Mao; Zengrong Zhu (Invertebrate Reproduction & Development, 2013)