Organization of endogenous clocks in insects

Helfrich‐Förster, Charlotte

doi:10.1042/bst0330957

Cited by 33 publications

(24 citation statements)

References 51 publications

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“…Even though the distributed location of circadian functions and the supposed lack of a conspicuous pacemaker in the brain may indicate that crustacean clock structures are significantly different from those in insects, the recent identification of some neurons in lobsters (H. americanus) that are homologous to clock neurons in Drosophila and other insects rather gives hints to expect strikingly similar organisations in insect and crustacean clocks. These PDH-ir neurons of the lobster are very similar to the s-LN v s that express the homologous neuropeptide PDF, a clock output of a group of Drosophila pacemakers, which controls the morning bout of locomotory activity (60,213,214), the coordinative l-LN v s of Drosophila (or optic lobe 2-neurons in Phormia terraenovae flies; 325) and the large PDFMe clock neurons of other insects innervating the accessory medulla and the contralateral optic lobes (213,215,216,318).…”

Section: Putative Clock Neurons Conserved In Crustaceans and Insectsmentioning

confidence: 97%

“…The Drosophila clock neuron clusters of a few morphologically and functionally distinct s-/l-LN v s and LN d s are likely a highly adapted clock system. However, PDH/PDF-ir neurons located next to the optic ganglia usually occur in most other insects (57,(316)(317)(318) and in diverse crustaceans (138,140,141) in much larger numbers. They could, thus, represent a clock organisation less specialised than that in Drosophila.…”

Section: Perspectivementioning

confidence: 99%

“…The central clock of most insects is located in the brain or next to optic ganglia of protocerebral origin (58,59,318). Even though the distributed location of circadian functions and the supposed lack of a conspicuous pacemaker in the brain may indicate that crustacean clock structures are significantly different from those in insects, the recent identification of some neurons in lobsters (H. americanus) that are homologous to clock neurons in Drosophila and other insects rather gives hints to expect strikingly similar organisations in insect and crustacean clocks.…”

Section: Putative Clock Neurons Conserved In Crustaceans and Insectsmentioning

confidence: 99%

“…57,[316][317][318]. Notwithstanding the differences that exist between insect species with regard to the distinct cellular locations and distributions of neuronal clock elements and regulatory clock genes or their products in the brain and/or the optic lobe (57,(316)(317)(318)(319), commonalities have perhaps best been documented for the locations of PDH/PDF-ir neurons close to the optic lobes and the role of PDF as a clock output factor (57,(316)(317)(318). The bearings on homologies and functional similarity of these neurons are discussed below (see 4.2.…”

Section: Evolution Of Circadian Pacemakers In Arthropodsmentioning

confidence: 99%

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Circadian clocks in crustaceans: identified neuronal and cellular systems

Strauß

Dircksen²

2010

Front Biosci

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Circadian rhythms are known for locomotory and reproductive behaviours, and the functioning of sensory organs, nervous structures, metabolism and developmental processes. The mechanisms and cellular bases of control are mainly inferred from circadian phenomenologies, ablation experiments and pharmacological approaches. Cellular systems for regulation summarised here comprise the retina, the eyestalk neuroendocrine X-organ-sinus gland system, several neuropeptides such as red pigment concentrating, hyperglycaemic and pigment-dispersing hormones, and factors such as serotonin and melatonin. No master clock has been identified, but a model of distributed clockwork involves oscillators such as the retinular cells, neurosecretory systems in the optic lobes, putative brain pacemakers, and the caudal photoreceptor. Extraretinal brain photoreceptors mediate entrainment. Comparative analyses of clock neurons and proteins known from insects may allow the identification of candidate clock neurons in crustaceans as putative homologues in the two taxa. Evidence for the existence of "insect-like" intracellular clock proteins and (light sensitive) transcription factors is scarce, but clock-, period-, and cryptochrome-gene products have been localised in the CNS and other organs rendering further investigations into crustacean clockwork very promising.

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Section: Putative Clock Neurons Conserved In Crustaceans and Insectsmentioning

confidence: 97%

Section: Perspectivementioning

confidence: 99%

Section: Putative Clock Neurons Conserved In Crustaceans and Insectsmentioning

confidence: 99%

Section: Evolution Of Circadian Pacemakers In Arthropodsmentioning

confidence: 99%

See 2 more Smart Citations

Circadian clocks in crustaceans: identified neuronal and cellular systems

Strauß

Dircksen²

2010

Front Biosci

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“…PDFs in insects act as circadian clock output factors that regulate clock neurons [11][12][13], activity phases, and photoresponsiveness during early night [14]. In Drosophila melanogaster, the lateral PDF neurons adjacent to the optic lobe are known to express the period gene product, PER [11,15,16], which occurs in crustaceans as well [17].…”

Section: Introductionmentioning

confidence: 99%

Pigment-dispersing hormone in Daphnia interneurons, one type homologous to insect clock neurons displaying circadian rhythmicity

Strauß

Zhang

Verleyen

et al. 2011

Cell. Mol. Life Sci.

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We report identification of a beta-type pigment-dispersing hormone (PDH) identical in two water flea species, Daphnia magna and Daphnia pulex. It has been identified by cloning of precursors, chromatographic isolation from tissue extracts followed by immunoassays and de novo-mass spectrometric sequencing. The peptide is restricted to a complex system of distinct interneurons in the brain and visual ganglia, but does not occur in neurosecretory cells projecting to neurohemal organs as in decapod crustaceans. Thirteen neuron types individually identified and reconstructed by immunohistochemistry were almost identical in terms of positions and projection patterns in both species. Several neurons invade and form plexuses in visual ganglia and major brain neuropils including the central body. Five neuron types show contralateral pathways and form plexuses in the lateral, dorsal, or postlateral brain neuropils. Others are local interneurons, and a tritocerebral neuron connects the protocerebrum with the neuropil of the locomotory second antenna. Two visual ganglia neuron types lateral to the medulla closely resemble insect medulla lateral circadian clock neurons containing pigment-dispersing factor based upon positional and projectional criteria. Experiments under 12:12 h light/dark cycles and constant light or darkness conditions showed significant circadian changes in numbers and activities of one type of medulla lateral PDH neuron with an acrophase in the evening. This simple PDH system shows striking homologies to PDH systems in decapod crustaceans and well-known clock neurons in several insects, which suggests evolutionary conservation of an ancient peptidergic interneuronal system that is part of biological clocks.

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The circadian clock network in the brain of different Drosophila species

Hermann

Saccon

Senthilan

et al. 2012

J of Comparative Neurology

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Comparative studies on cellular and molecular clock mechanisms have revealed striking similarities in the organization of the clocks among different animal groups. To gain evolutionary insight into the properties of the clock network within the Drosophila genus, we analyzed sequence identities and similarities of clock protein homologues and immunostained brains of 10 different Drosophila species using antibodies against vrille (VRI), PAR-protein domain1 (PDP1), and cryptochrome (CRY). We found that the clock network of both subgenera Sophophora and Drosophila consists of all lateral and dorsal clock neuron clusters that were previously described in Drosophila melanogaster. Immunostaining against CRY and the neuropeptide pigment-dispersing factor (PDF), however, revealed species-specific differences. All species of the Drosophila subgenus and D. pseudoobscura of the Sophophora subgenus completely lacked CRY in the large ventrolateral clock neurons (lLN(v) s) and showed reduced PDF immunostaining in the small ventrolateral clock neurons (sLN(v) s). In contrast, we found the expression of the ion transport peptide (ITP) to be consistent within the fifth sLN(v) and one dorsolateral clock neuron (LN(d) ) in all investigated species, suggesting a conserved putative function of this neuropeptide in the clock. We conclude that the general anatomy of the clock network is highly conserved throughout the Drosophila genus, although there is variation in PDF and CRY expression. Our comparative study is a first step toward understanding the organization of the circadian clock in Drosophila species adapted to different habitats.

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Organization of endogenous clocks in insects

Cited by 33 publications

References 51 publications

Circadian clocks in crustaceans: identified neuronal and cellular systems

Circadian clocks in crustaceans: identified neuronal and cellular systems

Pigment-dispersing hormone in Daphnia interneurons, one type homologous to insect clock neurons displaying circadian rhythmicity

The circadian clock network in the brain of different Drosophila species

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