Development of the circadian clock in the German cockroach, Blattella germanica.
The cell distribution and immunoreactivity (ir) against period (PER), pigment dispersing factor (PDF) and corazonin (CRZ), were compared between adults and nymphs in the central nervous system of the German cockroach. Although PER-ir cells in the optic lobes (OL) were expressed in the nymphs from the first instar, the links between major clock cells became more elaborated after second/third instar. A circadian rhythm of locomotion was initiated at the fourth/fifth instar. The results suggest that the clock was running from hatching, but the control network needed more time to develop. In addition, the putative downstream regulators, PDF-ir and CRZ-ir, are co-localized in various regions of the brain, indicating potential output routes of the circadian clock. CRZ-ir cells with typical morphology of neurosecretory cells in the dorsolateral protocerebrum send out three neural fibers to reach the ipsilateral corpora cardiaca (CC), the antennal lobe and two hemispheres of the protocerebrum. Based on co-localization with some PER-ir/PDF-ir cells, the CRZ-ir cells have the potential to serve as a bridge between circadian neural signals and endocrine regulation. Based on PDF's role in the regulation of locomotion, our results support the finding that the locomotor circadian rhythm is possibly controlled by a hormonal route.
Yang
Yung-Yu
YY
Department of Entomology, National Taiwan University, Taipei 106, Taiwan.
Wen
Chih-Jen
CJ
Mishra
Archana
A
Tsai
Chi-Wei
CW
Lee
How-Jing
HJ
D000818:Animals; D001683:Biological Clocks; D020048:Blattellidae / Q000235:genetics / Q000254:growth & development* / Q000502:physiology; D002490:Central Nervous System / Q000254:growth & development / Q000378:metabolism; D002940:Circadian Rhythm; D018507:Gene Expression Regulation, Developmental; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D009758:Nymph / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D056950:Period Circadian Proteins; D021381:Protein Transport
D009479:Neuropeptides; D009687:Nuclear Proteins; D056950:Period Circadian Proteins