ORIGIN OF PROTEINS RELEASED FROM BARLEY ROOTS BY OSMOTIC SHOCK

Proteins released from osmotically-shocked Hordeum vulgare roots were shown to originate primarily from the root and not from contaminating bacteria. The addition of 6 mg/l tetracycline to the culture solution 1 day before harvest reduced bacterial contamination of 5-day-old roots by 98% without adversely affecting the uptake of oxygen or orthophosphate, although root growth was suppressed. Calculations from bacterial counts indicated that the bacterial protein associated with tetracycline-treated roots could not account for more than 2% of the protein released by osmotic-shock treatments. Furthermore, electrophoretic separations on acrylamide gels using isoelectric focusing showed that patterns for bacterial proteins differed distinctly from those obtained from osmotically-shocked roots. © 1979.