Expression of Clock Genes in Cockroaches
Date Issued
2008
Date
2008
Author(s)
Wen, Chih-Jen
Abstract
The distributions of immunoreactivity (ir) cells against three clock-related proteins (Period, PER; Pigment Dispersing Factor, PDF; and Corazonin, CRZ) were compared between two species of cockroaches. The German cockroach, Blattella germanica, and the double-striped cockroach, B. bisignata, are sibling species with similar period sequence but distinctive circadian rhythm in locomotion. Three major groups of PER-ir cells are located in optic lobes (OLs), which are the sites of the major circadian clock. They are interconnected with PER-ir neural bundles. Interestingly, the potential output signal of the circadian clock, PDF, is co-localized with PER in all three groups of cells. However, only two CRZ-ir cells and their processes are found in the OLs and they are not co-localized with PER-ir or PDF-ir cells and processes. Since only one circadian rhythm is expressed in locomotion, the time signals from both major clocks in the OLs are coupled by connection with PDF-ir processes. A group of 3-4 PER-ir cells in the protocerebrum display typical characteristics of neurosecretary cells. In addition, there are numerous, small PER-ir and PDF-ir co-localized cells in the pars intercerebralis (PI) which have direct connections with the neurohemoorgan, corpora cardiaca (CC), through PER-ir and PDF-ir processes. Based on these findings, the cellular connection shows a circadian control through endocrine route. For the rest of central nervous system, only a few PER-ir and PDF-ir cells or processes are detected. This finding implies the circadian clock for locomotion is not located in subesophageal ganglion (SOG), thoracic or abdominal ganglia, but may use other neural messengers to pass on circadian signals. Since the overall distribution pattern of the clock cells are the same for B. germanica and B. bisignata, the possible explaination of the different expression of locomotion between the species depends on genes downstream of per, pdf and crz. The appendix at the end of the thesis is the the article “Distribution of Corazonin and Pigment-Dispersing Factor in the cephalic ganglia of termites”, which is accept by the journal “Arthropod structure and development”. We finished this work about termites by teamwork with our coauthors: Dr. Ivo Sauman, Dr. František Sehnal, Dr. Ivan Hrdý and Dr. Radka Závodská of Czech Republic.
Subjects
Period
Pigment Dispersing Factor
Corazonin
Blattella germanica
B. bisignata
Type
thesis
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