Multiple Factors Affecting Growth and Encystment of Acanthamoeba castellanii in Axenic Culture

John S. Cordingley ； Wendy C. Trzyna

《Acta Protozoologica》 47卷4期 (2008/12) Pp. 307-316

並列摘要

Acanthamoeba castellanii is a free-living amoeba that feeds on bacteria in the environment when growing and dividing but forms a cellulose-containing cyst when confronted with unfavorable conditions. What conditions are considered ”unfavorable” and how the amoeba senses these changes are not fully understood. In addition to encystment the amoebae show a remarkable degree of phenotypic flexibility in which their responses to some environmental conditions change over prolonged periods of time. The response to raised osmolarity remains stable for the Neff strain whereas the amoebae adapt to low temperatures by altering their behavior substantially but continue to grow and divide. In contrast elevated temperatures induce entry into stationary phase and encystment. The efficiency of encystment varies depending on the severity of the environmental challenge. Understanding the factors that affect the encystment process as well as any phenotypic flexibility and possible underlying genomic alterations that may occur over time in laboratory cultures are important variables to consider. This is especially pertinent as Acanthamoeba will potentially be a more widely utilized model system once the genome sequence is completed. A more comprehensive understanding of the details of growth and encystment in culture will contribute in this regard.

並列關鍵字

Encystment ； Acanthamoeba castellanii ； axenic culture ； phenotypic flexibility ； encystment efficiency ； osmolarity