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Not‐Adaptive Behavior of Isotropically Heated, Inert Populations of Oxytricha bifaria (Ciliophora, Stichotrichia)
Author(s) -
BARBANERA FILIPPO,
ERRA FABRIZIO,
BANCHETTI ROSALBA
Publication year - 2002
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/j.1550-7408.2002.tb00341.x
Subject(s) - biology , inert , adaptation (eye) , thermal , isotropy , biophysics , physics , optics , thermodynamics , quantum mechanics , neuroscience
. The physiological effects on isotropically heated populations of Oxytricha bifaria cultured at 24°C were investigated. At 34.6°C ciliates became inert, and did not adaptively react to either cold or warm microgradients; they neither moved towards the favorable cold thermal source nor escaped from the unfavorable warm one. The inert oxytrichas were only able to perform the Side‐Stepping Reaction (SSR) on the same spot. However, mobile ciliates at 31.6°C reacted to the cold microgradient by immediately orienting themselves towards its source, without accelerating but reducing their SSR frequency. Moreover, in a warm microgradient such ciliates immediately increased their SSR frequency, then moved away from the thermal source. At 34.6°C the behavior of ciliates was not‐adaptive—not acting to guide the organisms to more favorable conditions—whereas at 31.6°C it was still clearly adaptive. Therefore, the locomotory inertness of the oxytrichas at 34.6°C was the result of thermal stress rather than their behavioral response to the environmental isotropy, in contrast to populations of the same species made inert at 9°C.