Analysis of zebrafish (Danio rerio) behavior in response to bacterial infection using a self-organizing map.
BACKGROUND
Animal behavioral responses have been recently established as a suitable tool for detecting contaminants in the environment for risk assessment in situ. In this study, we observed movement behavior of zebrafish (Danio rerio) before and after infection with Edwardsiella tarda CK41 for 3 days until death.


METHODS
Infection status of zebrafish was confirmed through PCR and colonization assay as time progressed and lesion development in the tails of zebrafish was also examined. Movement behaviors in response to bacterial infection were patterned by self-organizing map (SOM) based on movement parameters, including speed (mm/s), acceleration (mm/s (2) ), stop duration (t), stop number (n), locomotory rate (mm/s), turning rate (rad/s), and meander (rad/mm).


RESULTS
According to SOM result, clusters were identified firstly according to time and secondly according to infection. Two movement patterns were observed in the early period of infection: one group with minimum turning rate and meander (i.e., stiff movement) and the other group with maximum strop number. Late infection was characterized by long stop duration.


CONCLUSIONS
SOM was suitable for extracting complex behavioral data and thus can serve as a referencing system for diagnosing disease development in order to reveal the mechanism of the infection process.
Department of Biological Sciences, Pusan National University, Busan, 609-735, Republic of Korea. lsb5162@gmail.com.
Sang-Bin
SB
Lee
Department of Microbiology, Pusan National University, Busandaehak-ro, 63beon-gill, Geumjeong-gu, Busan, 609-735, Republic of Korea. yunjeongchoe1105@gmail.com.
Yunjeong
Y
Choe
Department of Biological Sciences, Pusan National University, Busan, 609-735, Republic of Korea. tschon.chon@gmail.com.|Ecology & Future Research Association (EnFRA), 21 Dusil-ro, 45 beon-gil, Geumjeong-gu, Busan, 609-802, Republic of Korea. tschon.chon@gmail.com.
Tae-Soo
TS
Chon
Department of Microbiology, Pusan National University, Busandaehak-ro, 63beon-gill, Geumjeong-gu, Busan, 609-735, Republic of Korea. hoykang@pusan.ac.kr.
Ho Young
HY
Kang
D000818:Animals; D001522:Behavior, Animal; D020609:Edwardsiella tarda; D004756:Enterobacteriaceae Infections / Q000150:complications / Q000382:microbiology / Q000662:veterinary*; D005393:Fish Diseases / Q000209:etiology / Q000382:microbiology*; D009043:Motor Activity; D015027:Zebrafish