Project title: Radiation-induced allelopathy between living organisms studied using zebrafish embryos

Radiation-induced bystander effect (RIBE) in living organisms describe the phenomenon that unirradiated organisms respond as if they have been irradiated, after contacting with the irradiated organisms or being exposed to the medium previously conditioning the irradiated organisms. RIBE has been demonstrated to exist between fish and between mice. RIBE in living organisms has been suggested as an evolutionarily conserved effect which enables an effective population response. Our group has recently studied using zebrafish embryos the benefit of RIBE in terms of induction of radioadaptive response (RAR) by communication of radiation-induced bystander signals. RAR is a low-dose effect, which occurs when a small preceding priming dose decreases the biological effectiveness of a subsequent large challenging dose. We have also recently discovered that the stress communicated between the unirradiated zebrafish embryos and the irradiated embryos sharing the same medium will help “rescue” the irradiated embryos, and that the strength of the rescue effect depends on the number of rescuing bystander unirradiated embryos. These allelopathic effects will be studied in more details while other allelopathic effects will also be identified, and the possible mechanisms will be examined.


Choi, V.W.Y., Cheng, S.H., Yu, K.N., 2010. Radioadaptive Response Induced by Alpha-Particle-Induced Stress Communicated in Vivo between Zebrafish Embryos. Environmental Science & Technology, 44, 8829-8834.


Choi, V.W.Y., Ng, C.Y.P., Cheng, S.H., Yu, K.N., 2012. α-Particle irradiated zebrafish embryos rescued by bystander unirradiated zebrafish embryos. Environmental Science & Technology, 46, 226–231.

Supervisor: Prof Peter K N Yu (

Suitable for: M.Phil. or Ph.D.

A good degree in radiation biophysics or biology