Task: Named Entity Recognition
Input (English):  Isolated X . laevis oocytes incubated in medium containing 25 microgram DNA / ml labeled with either 125I , 32P or 14C and from three different sources ( bovine , E . coli and X . laevis ) , incorporated the label at an average rate of 0 . 11 ng . mm - 2 . hr - 1 .
Output (English): oocytes