Go toArchive
Browse byFacets
Bookbag ( 0 )
'Ca2 + Calmodulin' in keywords Facet   Publication Year 1984  [X]
Results  1 Item
Sorted by   
Section
Publication Year
1984[X]
1Author    Ken GotoRequires cookie*
 Title    in Lemna  
 Abstract    Biochemical aspects o f circadian rhythms were studied using a long-day duckweed, Lem na gibba G 3 cultured in short day condition (9 h light at 3800 lux follow ed by 15 h darkness), which was transferred in continuous light (LL) at the end (LL 0) o f the last night period. With such a system I have previously reported a rhythm o f affinity for N A D + o f cytoplasm ic N A D -dependent glyceraldehyde 3-phosphate dehydrogenase (C yt-N A D -G P D) 180° out o f phase with that o f affinity for N A D P + o f chloroplastic N A D P -dependent G PD (C h l-N A D P -G P D) and that N A DP+ could increase in vitro the affinity for N A D P + o f C h l-N A D P -G PD . I report here that NA D P+ can decrease in vitro the affinity for N A D + o f C yt-N A D -G P D as well, and furthermore, that the in vivo level o f N A D P + oscillates in phase with the rhythm o f the affinity for N A D P + o f Chl-NADP-GPD. Moreover, I found the existence o f m irror-image circadian rhythms, o f com parable am pli­ tudes, o f in vivo levels o f N A D + + N A D H (total N A D) (with peaks, as the ones o f C yt-N A D -GPD. at LL 0 and 24) and o f N A D P + + N A D P H (total N A D P) (with peaks, as the ones o f Chl-NADP-G PD, at LL 12 and 36). Consequently, a circadian rhythm in the rate o f net in vivo production o f total N A D P (or N A D) m ight be expected 90° in advance o f that in the level o f total NADP (or N A D). Indeed. I found oscillations in the activities o f N A D kinase and o f NA DP phosphatase with peaks occurring, respectively, at LL 6 and at LL 18. Moreover, in vitro treatments with EGTA (a Ca2+-chelator), chlorprom azine and W 7 (both inhibitors o f cal­ modulin) were able to both inhibit N A D kinase from its highest level o f activity to its m inim al one and activate N A D P phosphatase from its lowest level o f activity to its maxim al one. I conclude, therefore, that the in vivo level o f C a2+-calm odulin could oscillate in phase with the rhythm o f N A D kinase activity and induce the mirror-image circadian rhythms o f activities o f NA D kinase and o f NA D P phosphatase. I propose that the control sequence among the several circadian rhythms I studied could start with changes in Ca2+-calm odulin, then proceed through oscillations in N A D kinase and N A D P phosphatase activities, leading to changes in N A D +, N A D P +, and N A D P H levels, which would themselves induce the C hl-N A D P -G PD and C yt-N A D -G P D rhythms. 
  Reference    Z. Naturforsch. 39c, 73 (1984); received June 16/Septem ber 19 1983 
  Published    1984 
  Keywords    Ca2+-Calmodulin, Circadian Rhythms, G lyceraldehyde 3-Phosphate Dehydrogenases (EC 12 
  Similar Items    Find
 DEBUG INFO      
 TEI-XML for    default:Reihe_C/39/ZNC-1984-39c-0073.pdf 
 Identifier    ZNC-1984-39c-0073 
 Volume    39