ISOLATION AND IDENTIFICATION OF BDELLOVIBRIO FROM COASTAL AREAS OF TAIWAN

A survey of the occurrence and characteristics of Bdellovibrio around the coastal areas and aqua-cultural ponds of Taiwan was conducted. The recovery rate of bdellovibrios was highest in estuaries during summer . Prey-dependent Bdellovibrio sp. strain TS-S and strain TS-V were iso lated from the estuary of the Tam-shui river, from which prey-independ ent strains were further selected by streptomycin treatment or by usin g enriched medium. Their mutation rates were 1.2 x 10(-6) (streptomyci n method) and 3.8 x 10(-6) (enriched medium) for the strain TS-S and 1 .1 x 10(-5) (streptomycin method) and 2.1 x 10(-6) (enriched medium) f or the strain TS-V. Four prey-independent mutants were isolated from s train TS-S by the enriched medium method and designated as Bdellovibri o sp. strains TS-S-PI1 through TS-S-PI4. Similarly, two prey-independe nt mutants, designated as TS-V-PI1 and TS-V-PI2, were obtained from st rain TS-V. The physiological characteristics of these six prey-indepen dent mutants differed from those of the three species (Bdellovibrio ba cteriovorus, B. stolpii, and B. starrii), in comparisons by biochemica l tests and electron microscopic examination. The average cell sizes o f TS-S-PIs and TS-V-PIs, were 0.18 x 0.85 and 0.21 x 0.78 mu m, respec tively. These sizes are smaller than the cell sizes of the three speci es shown in Bergey's Manual.