This paper deals with the transformation of knowledge expressed in the natural language into symbolic expressions. It is shown that rules supplied from experts can be transformed by computer into such symbolic expressions as enable using the logic programming to make the plausible inferences. These symbolic expressions are stored in the knowledge base and represent the knowledge acquired from experts. First, the synthesis of the symbolic expression representing the initial knowledge in the knowledge base is considered. Then, the problem of acquiring new elements of knowledge for the knowledge base is argued. Finally, a way of transforming the symbolic expressions into PROLOG rules is introduced. Keywords: expert system, knowledge representation, knowledge integration, logic programming.