USE OF POLYACRYLIC-ACID TO PREVENT MYCELIAL AGGREGATION OF USTILAGO-NUDA IN AGITATED LIQUID CULTURE

Polyacrylic acid (MW = 4000) prevented mycelial aggregation of Ustilago nuda teliosporelings in agitated liquid culture while polyacrylic acid (MW = 1800) did not. Results of a simple simulation suggest that the anti-aggregation effect of the 4 x 10(6) MW polyacrylic acid involves the prevention of contact of sporeling surfaces through coating of hyphae. However, unambiguous surface coating of sporelings was not visible in the scanning electron microscope. Sporelings grown in 4 x 10(6) MW polyacrylic acid could not be stained using three procedures which effectively stained sporelings grown without polyacrylic acid. Interference with staining also suggests that polyacrylic acid is deposited on sporelings as a persistent coating. Although useful in preventing mycelial aggregation, polyacrylic acid limits cytological studies of U. nuda sporelings.