1. BIOLOGICAL RHYTHMS CHRONOBIOLOGY The imperceptible movement of plants
The bird navigation
The vigil-sleep cycle
At the basis of the life.
A multidisciplinary argument

2. What is a BIOLOGICAL CLOCK
A molecular / physiological device which synchronizes activities in the living organisms
Oscillation CLOCKS
hourglass
time chain of events

3. BIOLOGICAL CLOCKS OSCILLATING CLOCKS
autochthonous pacemaker (to measure time), generates and checks automatically the endogenous rhythms (infra-, circa-, ultra-diane)
independently by
environmental messages.

4. BIOLOGICAL CLOCKS HOURGLASSES measure time intervals,
need environmental signals which periodically switch they on

5. BIOLOGICAL CLOCKS Oscillating Clocks
Many have different oscillatory frequencies.
They can be classified on the basis of the
living organisms on the basis of
Environmental time scale (temperature compensated)
Biological time scale (not temperature compensated)   
Oscillating Clocks
Hourglasses – they define a time span
(e.g. embryo development, pregnancy, etc.)
Multiple clocks
Mixed oscillating/hourglass [some cellular functions]
Mixed periodicity (endogenous/exogenous)

6. INFRADIAN RHYTHMS YEAR, SEASON, MONTH, WEEK
Germination : 1 year (plants)
Lethargy : in Citellus lateralis of days
Migrations : in Silvidae (Passeriformes)
Menstruation days
(moon cycle days)

7. CIRCADIAN RHYTHMS About 24 h Independent from external stimuli
Free runners, when independent from environmental regulators
Examples: Vigil-sleep cycle
Body temperature cycle

8. with a rest – recharge cycle.
ULTRADIAN RHYTHMS
From unicellular organisms to mammalians, from physiological to cognitive processes
Rhythmic phenomena independent from the circadian, with which they probably interact
Periods of 1.5 – 3 hours are very common
They reflect an economy principle avoiding to spend energy continuously,
with a rest – recharge cycle.

9. The spontaneous (locomotion) activity is a parameter useful for chronobiology studies.
Each biological clock should have the following features:
Rhythm persistence
Period temperature – compensated
A mechanism conservative among species
techniques used for the study of the circadian rhythms require a spectral analysis is required (e.g., the Fourier Analysis)

10. MATHEMATIC – STATISTICAL ANALYSIS TO STUDY BIOLOGICAL RHYTHMS
The Fourier analysis derives from the researches of Jean Baptiste Joseph Fourier (beginning of the XIX century), who demonstrated that each continuous function can be the result of a sum of infinite opportune sinusoidal functions.
The series of simple functions which result from the decomposition of a complex function is called the
Fourier Series

11. FOURIER’S ANALYSIS

12. Period 20-24 h 1 Day = 24 h = 1440 min 480 min = 8,0 h

13. Spectrum power
24 h
12 h
8 h
4 h

14. Monitoring of the mouse’s locomotory activity
12 mice were monitored by radar
in their single cages

15. LD
CIRCADIAN
ULTRADIAN DD

16. ___________________________________
A JUMP INTO THE DARK

17. Within the true caves the light cycle is absent
WHY CAVE ANIMALS
Within the true caves the light cycle is absent

18. Dolichopoda geniculata
A trogloxenic species

19. #A2 - D.g.geniculata (N), Pastena Cave

20. FIRST DATA
ON CAVE MYSIDACEA

21. Spaeleomysis bottazzii
A troglobiont (stygobiont) species

22. Each animal interrupts a infrared beam when it moves into its aquatic environment
Problems:
Animal habitat
Water
Warming of the apparatus
De-sinchronization (aclimatization)

23. RESULTS Spelaeomysis bottazzii #1

24. Spelaeomysis bottazzii shows a pattern of activities (the ACTOGRAM) very similar to that of insects and mammalians

26. CONCLUSIONS
The circa-dian is not the only rhythm for the mobility activity of animals
The ultra-dian components do not depend from the circadian ones
The ultra-dian components are not regulated by photoperiod, but they show higher amplitudes when the circadian is isolated from any photoperiods
They are temperature compensated
They stay even in troglobionts (as mysidaceans)

27. What about Mysidacea migrating in-out a marine cave?
the Ciolo cave: Hemimysis margalefi & Siriella jaltensis

28. 29-30 / 12 / 2006
12.00
00.30
220 specimens H. margalefi
In lab at 19.5 °, L 24 h, yeast

29. 20-40 specimens
1 litre aquarium
Black room
Uninterrupted recording for 5 days
the aquarium the light spot
the rec. apparatus the videocam

30. a recorded image was analyzed every 30 min.
Each square (of 24) was characterized with the specimen number it contained.
The sequence (of 30 min intervals) obtained was passed through the Fourier analyses

31. Hemimysis margalefi, 38 specimens, 5 days, L 24 h

32. RESULTS &
CONCLUSIONS
Hemimysis margalefi shows an activity cycle of 23 h
It does not go outside the cave
Siriella jaltensis is absent from the cave during winter.
It arrives in caves during spring
It goes out of the cave during night
It did not show any activity during behavioral experiments