Inhibition of Extracellular DNase Activity of Barley Microspores in the Presence of Polyethylene Glycol and Silicon Carbide Fibers

Nucleolytic activity was detected extracellularly in barley microspore (MS) cultures directly for up to 6 days after isolation. Treatment of MS with polyethylene glycol (PEG) enhanced nucleolytic activity, whereas the addition of silicon carbide fibers (SCF) resulted in some protection of DNA. Extracellular nucleolytic activity was reduced when MS were treated with 12% PEG after addition of a mixture of 8 mmol/L dNTP, 8 mmol/L EDTA, 40 mmol/L spermidine and 1.7 mg/mL proteinase K. In the presence of SCF a mixture without nucleotides was also effective. Gene transfer approaches with PEG and SCF were carried our under conditions of nuclease inhibition, but transient GUS activity was obtained very rarely.