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A Shake Culture Method for Pythiaceae Applicable to Rapid, Small-Scale Assay of Vegetative Physiology. Carroll D. Rawn, Research Associate, Department of Plant Pathology, University of Nebraska, Lincoln, NE 68583; James L. Van Etten, professor, Department of Plant Pathology, University of Nebraska, Lincoln, NE 68583. Phytopathology 68:1384-1388. Accepted for publication 28 March 1978. Copyright © 1978 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-68-1384.

A method is described for growing uniform mycelial suspensions of Pythium ultimum and Phytophthora megasperma var. sojae in a defined medium in shake culture. Dry weight doubling times of these fungi were 5 to 6 hr and about 12 hr, respectively. Incorporation of radioactive leucine, adenine, glycerol, and acetate into proteins, nucleic acids, and lipids by 3-ml cultures could be measured easily with 10-min pulse periods. These synthetic activities were blocked in a predictable fashion if the cell samples were pretreated for 10 min with a variety of inhibitors known to impair specific cytoplasmic and mitochondrial functions. The cultures were maintained easily, and after about 12 hr from the seeding of fresh cultures they were ready for use. The rapid growth and the ease and reproducibility of sampling make possible short-term manipulations of small amounts of cell material as well as the rapid production of large amounts of uniform, actively growing mycelium.