INVESTIGADORES
VALENTINUZZI veronica Sandra
congresos y reuniones científicas
Título:
Photoperiodismo in Subterranean Rodents: Lab, Field and Modeling
Autor/es:
ODA GA; FLORES DANILO EFL; TACHINARDI P; JANNETTI MG; IMPROTA CG; SILVA JEFFERSON; VALENTINUZZI VS
Lugar:
Amelia Island, Florida-Virtual
Reunión:
Congreso; SRBR- Society for Research in Biological Rhythms; 2020
Institución organizadora:
SRBR Society
Resumen:
Background, Objectives: Organisms that inhabit the extreme photicsubterranean environment provide an opportunity to verify minimum daily photic input for daily entrainment and photoperiodism. The aim of the present study was to verify if South American subterranean rodents (Ctenomys aff. knightii), known as tuco-tucos displayed photoperiodic time measurement through internal coincidence and minimum light inputs that sustain this mechanism. Methods: In the Lab, 76 tuco-tucos were divided into groups and maintained in 6 artificial photoperiods (LD3:21,6:18,9:15,12:12,15:9,18:6,21:3 L=1000Lux,T=24 o C±2) to verify effects on daily running-wheel activity onset and duration. In the Field, 12 tuco-tucos (4 males and 8 females, 188±27g) were released into individual semi-natural enclosures (12 X 6 X 1.5m and 1m deep) during summer and winter carrying activity sensor accelerometers and light sensor light-loggers, then recaptured after a minimum of 15 days. Also, 10 freshly caught animals in summer and 10 in winter were released directly to laboratory DD with running-wheels for 15 days. Mathematical Modeling: a two coupled Pavlidis limit-cycle oscillator system under two daily light pulses was simulated. Each light pulse was constrained to input only one of the E/M oscillators and their timing to occur at random times but limited either to the interval from daily light onset to12:00 (midday) or from 12:00 to light offset. Light onset and offset times were then varied according to the annual photoperiod variation to verify the effects on simulated activity onset and duration. Results and Conclusions: Subterranean tuco-tucos displayed photoperiod aftereffects of natural entrainment and seasonal patterns of daily activity onset, duration and light exposure in the field. In the lab, they presented photoperiod dependent responses of activity onset and duration similar to those of epigeous rodents. These experimental results from lab and field studies indicate that subterranean rodents are fully able to perform photoperiodic time measurement. Simulations showed that the modeled minimum light regimen is sufficient to change the phase relationship between two coupled circadian oscillators, enabling photoperiod measurement through an internal coincidence mechanism. Sponsors: FAPESP, CONICET.