A comparative view of insect circadian clock systems

SUMMARYAlthough the molecular mechanisms that control circadian rhythms in many animals, particularly in the fly, are well known, molecular and biochemical studies addressing the location and function of the proteins and genes contributing to the cycling of the clock in crayfish Procambarus clarkii are scarce. In this study, we investigated whether three proteins that interact in the feedback loop of the molecular clock described for Drosophila are expressed in the putative circadian pacemakers of crayfish retina, eyestalk and brain and whether their expression cycles in a manner consistent with elements of the circadian clock. Here we identified PER, TIM and CLK immunoreactivity in the cytoplasm and nucleus of cells located in the retina as well as in clusters of cells and neuropils of the optic ganglia, lateral protocerebrum and brain. Brain clusters 6, 10, 9 and 11, in particular, showed Per, Tim and Clk-like immunoreactivity at the perikarya and nucleus, and these antigens colocalized at Zeitgeber time (

Section: Discussionmentioning

confidence: 66%

Putative pacemakers of crayfish show clock proteins interlocked with circadian oscillations

Escamilla‐Chimal

Velázquez-Amado

Fiordelisio

et al. 2010

“…The sensitivity of this approach is most impressively highlighted by the detection of circadian rhythm gene transcripts. In the insect species in which it has been studied, the expression of many circadian clock genes is restricted to small cell groups in the brain (Tomioka and Matsumoto, 2010). While the spatial expression characteristics of clock genes in P. hirtus remain to be determined, it is reasonable to conclude that the sensitivity of RNA sequencing has enabled the comprehensive characterization of phototransduction and clock gene expression using a very marginally cell type-enriched tissue sample.…”

Section: Discussionmentioning

confidence: 99%

“…Remarkably, eutroglophilic and troglobiotic ground beetles exhibit day length entrainment of diurnal activity rhythms (for a review, see Lamprecht and Weber, 1992). To explore the potential for a role of vision in circadian entrainment, we also probed the P. hirtus transcript database for the presence of clock gene orthologs because the expression of clock genes is concentrated in neuronal cell clusters in the brain of insects (for a review, see Tomioka and Matsumoto, 2010). This search revealed the expression of all components of the insect clock gene core network that have been identified in Tribolium (Table3) (Cortes et al, 2010), including the bHlH-PAS transcription factor genes period (per), cycle (cyc), tango (tgo), clock (clk) and timeless (tim) as well as interacting genes like Par-domain protein 1 (Pdp1) and vrille (vri).…”

Section: Conservation Of Circadian Clock Gene Expressionmentioning

confidence: 99%

Phototransduction and clock gene expression in the troglobiont beetlePtomaphagus hirtusof Mammoth cave

Friedrich

Chen

Daines

et al. 2011

SUMMARYObligatory cave species exhibit dramatic trait modifications such as eye reduction, loss of pigmentation and an increase in touch receptors. As molecular studies of cave adaptation have largely concentrated on vertebrate models, it is not yet possible to probe for genetic universalities underlying cave adaptation. We have therefore begun to study the strongly cave-adapted small carrion beetle Ptomaphagus hirtus. For over 100 years, this flightless signature inhabitant of Mammoth Cave, the world's largest known cave system, has been considered blind despite the presence of residual lens structures. By deep sequencing of the adult head transcriptome, we discovered the transcripts of all core members of the phototransduction protein machinery. Combined with the absence of transcripts of select structural photoreceptor and eye pigmentation genes, these data suggest a reduced but functional visual system in P. hirtus. This conclusion was corroborated by a negative phototactic response of P. hirtus in light/dark choice tests. We further detected the expression of the complete circadian clock gene network in P. hirtus, raising the possibility of a role of light sensation in the regulation of oscillating processes. We speculate that P. hirtus is representative of a large number of animal species with highly reduced but persisting visual capacities in the twilight zone of the subterranean realm. These can now be studied on a broad comparative scale given the efficiency of transcript discovery by next-generation sequencing.

“…Although circadian rhythms have been described in a variety of insects, studies across multiple levels of analysis have been done in only a few species [e.g. Drosophila, cockroaches and crickets (Panda et al, 2002;Tomioka and Matsumoto, 2010)]. Furthermore, with the exception of just two studies (Rossel, 1979;Horridge et al, 1981), no analyses have been done using praying mantises (Insect: Mantodea).…”

Section: Introductionmentioning

confidence: 99%

Circadian rhythms affect the electroretinogram, compound eye color, striking behavior, and locomotion of the praying mantis,Hierodula patellifera(Serville)

Schirmer

Prete

Mantes

et al. 2014

Many behaviors and physiological processes oscillate with circadian rhythms that are synchronized to environmental cues (e.g. light onset), but persist with periods of ~24 h in the absence of such cues. We used a multilevel experimental approach to assess whether circadian rhythms modulate several aspects of the visual physiology and behavior of the praying mantis Hierodula patellifera. We used electroretinograms (ERGs) to assess compound eye sensitivity, colorimetric photographic analyses to assess compound eye color changes (screening pigment migration), behavioral assays of responsiveness to computer-generated prey-like visual stimuli and analyses of locomotor activity patterns on a modified treadmill apparatus. Our results indicate that circadian clocks control and/or modulate each of the target behaviors. Strong rhythms, persisting under constant conditions, with periods of ~24 h were evident in photoreceptor sensitivity to light, appetitive responsiveness to preylike stimuli and gross locomotor activity. In the first two cases, responsiveness was highest during the subjective night and lowest during the subjective day. Locomotor activity was strongly clustered around the transition time from day to night. In addition, pigment migration and locomotor behavior responded strongly to light:dark cycles and anticipated the light-dark transition, suggesting that the circadian clocks modulating both were entrained to environmental light cues. Together, these data indicate that circadian rhythms operate at the cellular, cellular systems and organismal level in H. patellifera. Our results represent an intriguing first step in uncovering the complexities of circadian rhythms in the Mantodea.