REACTIVATION OF ESCHERICHIA-COLI-CELLS, INACTIVATED BY ULTRAVIOLET RAYS, WITH CELL-EXTRACTS OF PROPIONIC-ACID BACTERIA - FRACTIONATION OF THE EXTRACT

Separation of Propionibacterium shermanii extract into fractions and t esting them for their reactivating effect on UV-inactivated Escherichi a coli AB-1157 cells showed that the activity was associated with the fraction of soluble proteins. The activity was not demonstrated in the fractions of RNA, DNA, ribosomes, or cell walls. Fractional salting o ut and subsequent testing of the fractions showed two active protein f ractions: fraction I (20-40% of ammonium sulfate saturating concentrat ion) and fraction II (60-80%). These fractions were separated by HPLC into seven and eight subfractions, respectively. Reactivating activity was showed in subfraction 4 (fraction I) and subfractions 5 and 6 (fr action II). Electrophoresis showed five and four polypeptides in subfr actions 4 and 5, respectively. Subfraction 6 (fraction II) contained o ne protein with a molecular mass of about 30 kDa. This protein apparen tly, was responsible for the protective properties of fraction II.