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RELATIONSHIP OF TOTAL VIABLE AND CULTURABLE CELLS TO EPIPHYTIC POPULATIONS OF PSEUDOMONAS SYRINGAE
Citation:
Wilson, M. AND S. Lindow. RELATIONSHIP OF TOTAL VIABLE AND CULTURABLE CELLS TO EPIPHYTIC POPULATIONS OF PSEUDOMONAS SYRINGAE. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-93/291.
Description:
The accuracy of the plate count method used routinely for enumeration of viable bacterial populations in natural environments is limited by the culturability of the target population. he method was modified to examine epiphytic populations of Pseudomonas syringae. iable population sizes determined from the number of cells that elongated when incubated with yeast extract and nalidixic acid were compared with those determined by the conventional plate count method. he plate count method accurately determined the number of viable cells in epiphytic P.syringae populations in a state of active growth under conditions of high relative humidity. he plate count method also accurately determined the number of viable cells in P. syringae inoculum, or a growing P.syringae population, subject to desiccation stress under conditions of low relative humidity. n epiphytic populations of P.syringae older than 80 h, however, the plate count underestimated the viable-population size by about two- to fourfold, suggesting that up to 7501 of the P.syringae population was nonculturable. he possible underestimation of viable-population size under some circumstances should be considered in epidemiological studies of phytopathogenic bacteria and when genetically engineered microorganisms in terrestrial ecosystems are monitored.