A bacterial factor induces changes in XXXX proteinase forms in the cellular slime mould @entity4328 .

@entity462 @entity9238 @entity526 @entity4328 @entity1068 @entity375 @entity3881 @entity7178
The electrophoretic pattern of @entity462 proteinases in axenically grown myxamoebae of @entity4328 can be altered by the addition of either Gram-negative ( @entity9238 , @entity526 ) or Gram-positive ( @entity7178 , @entity3881 ) bacteria to the culture. No changes occurred, however, if either @entity375 or latex beads were used in place of bacteria. The changes involved the simultaneous loss of proteinases characteristic of the axenic cells (the A-forms) and the acquisition of those found in cells which have been grown on bacteria (the B-forms). Using @entity9238 the conversion was complete within 4 h. Extracellular proteinase activity was unaffected during this period. After the @entity4328 cells had been lysed, no equivalent change in proteinase band pattern could be produced either by prolonged incubation of cell extracts or by treatment with proteinases. An identical conversion could be induced in cultures of myxamoebae by a factor, @entity462 proteinase converting factor (CPCF), present in the 15,000 g supernatant of a sonicated suspension of @entity9238 . CPCF was macromolecular, as demonstrated by both ultrafiltration and gel filtration, acid-precipitable, but was soluble in @entity1068 or alkali. Its activity was unaffected by treatment with trypsin. The results suggested that CPCF might be a component of the bacterial cell wall, and since its activity was affected by lysozyme treatment, peptidoglycan is implicated. The results can be interpreted in terms of a novel nutrient-dependent post-translational change which affected most of the @entity462 proteinases present in @entity4328 myxamoebae.
