Microbial Ecology

, Volume 20, Issue 1, pp 75-84

First online:

Changes of traits in a bacterial population associated with protozoal predation

  • Shuichi ShikanoAffiliated withBiological Institute, Faculty of Science, Tohoku University
  • , Leo S. LuckinbillAffiliated withDepartment of Biological Sciences, Wayne State University
  • , Yasushi KuriharaAffiliated withBiological Institute, Faculty of Science, Tohoku University

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access


In an attempt to understand the significance of predation in the evolution of prey species, the ecological and morphological characteristics of bacterial species under predation by a ciliated protozoa,Cyclidium sp., were investigated. Serial transfer at 7 day intervals was applied to the bacterial populations in the presence or absence ofCyclidium. Although cells of the parental bacterial strain are typically short rods up to 1.5 μm long, cells of much greater length, up to 20 μm long (type L) were found in populations exposed to predation fromCyclidium. However, the wildtype, shorter length bacteria persisted even after the appearance of type L. Type L was not observed in the singl bacterial culture throughout the serial transfers. Type L appeared to improve the ability to escape predation by elongating cell size, but growth rate and saturation density were decreased.