1. MCB 186 CIRCADIAN BIOLOGY CIRCADIAN PHOTORECEPTION USES DIFFERENT RECEPTORS and PATHWAYS FROM VISION October 26, 2005 J. W. Hastings

2. HOW DOES LIGHT ENTRAIN THE CIRCADIAN CLOCK? Action spectra should reveal the photoreceptor molecules involved What is the “action”? Phase shifts; Tau; Amplitude of Rhythms

3. DOES CIRCADIAN PHOTORECEPTION USE THE SAME MOLECULES AS FOR OTHER PHOTORESPONSES? e.g.,PHOTOTAXIS, PHOTOMOVEMENT, VISION

4. OKAZAKI LARGE SPECTROGRAPH: placing samples

5. OKAZAKI LARGE SPECTROGRAPH: 1 cm= 1 nm

6. GONYAULAX ACTION SPECTRUM FOR PHASE SHIFTING BY 3 HOUR LIGHT EXPOSURES

7. The HORSESHOE CRAB Limulus polyphemus SEVERAL PAIRS of EYES; ALL PARTICIPATE in CLOCK PHOTORECEPTION but TELSON (TAIL) RECEPTORS are DOMINANT

8. THE SEVERAL EYES and MANY PHOTORECEPTORS of the HORSESHOE CRAB Limulus Barlow, Scientific American, April 1990 All receptors have phase shifting effects on circadian rhythm; most effective are those in the tail Renniger et al.1988 J. Comp.Physiol 162: 127-140

9. PHASE SHIFTING by LIGHT ONLY to the TAIL Renniger et al.1988 J. Comp.Physiol 162: 127-140 Horseshoe Crab Limulus

10. PHASE RESPONSE CURVE for LIGHT PULSES TO TAIL Limulus Renniger et al.1988 J. Comp.Physiol 162: 127- 140

11. Chlamydomonas PHOTOTAXIS RHYTHM in constant light KONDO

12. Replace Vitamin A in Rhodopsin with an analog in Chlamydomonas Foster et al 1984 Nature 311: 756-759 Since the absorption spectra are different the action spectra should differ

13. CHLAMY ACTION SPECTRA for PHOTOTAXIS with DIFFERENT ANALOGS Foster et al 1984 Nature 311:756-750

14. ACTION SPECTRA FOR PHASE SHIFTING IN CHLAMY KONDO ET AL, 1989

15. PHASE SHIFTS with DIFFERENT COLORS of LIGHT-CHLAMY

16. PHASE SHIFTS DIFFER with COLOR of LIGHT in CHLAMY

17. Drosophila NO EFFECT of NO beta CAROTENE on CIRCADIAN PHOTORECEPTION Zimmerman & Goldsmith Science 1980

18. EFFECT of LIGHT INTENSITY on TAU in a BLINDED SPARROW M. MENAKER, 1968 PNAS 59: 414-421

19. BLIND SPARROW IS ENTRAINED BY LIGHT (DIM) M. Menaker

20. EYES REMOVED; LIGHT ENTRAINMENT VIA BRAIN (Menaker,1970) feathers plucked 1. from back 2. from head 3. feathers growing back; replucked 4. India ink under skin on head 5. ink removed

21. Chlamydomonas PHASE RESPONSE CURVE