Circadian Performance of Suprachiasmatic Nuclei (SCN)-Lesioned Antelope Ground Squirrels in a Desert Enclosure

DeCoursey, Patricia J.; Krulas, Jill R; Mele, Gary; Holley, Daniel C.

doi:10.1016/s0031-9384(97)00263-1

Cited by 124 publications

(72 citation statements)

References 25 publications

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“…Correlation between development time and circadian clocks was also reported in laboratory selection studies on melon flies (Miyatake, 1997b;Shimizu et al, 1997) and fruit flies (Kumar et al, 2006;Takahashi et al, 2013;Yadav and Sharma, 2013a). Disruption of circadian timing systems results in reduced reproductive output in the gypsy moth, Lymantria dispar (Giebultowicz et al, 1990), and D. melanogaster (Beaver et al, 2002;Beaver et al, 2003), shortening of adult lifespan in D. melanogaster (Hendricks et al, 2003;Kumar et al, 2005), reduction in vegetative growth and survivorship in Arabidopsis thaliana (Dodd et al, 2005), and increased predation in free-living ground squirrels Spermophilus lateralis (DeCoursey et al, 1997) and chipmunks Tamias striatus (DeCoursey et al, 2000). Furthermore, circadian clocks in resonance with environmental light/dark (LD) cycles have been shown to enhance adult lifespan of D. melanogaster (Pittendrigh and Minis, 1972;Klarsfeld and Rouyer, 1998) and blow flies Phormia terraenovae (von Saint Paul and Aschoff, 1978), and competitive ability in cyanobacteria Synechococcus sp.…”

Section: Introductionmentioning

confidence: 74%

Correlated changes in life history traits in response to selection for faster pre-adult development in the fruit fly Drosophila melanogaster

Yadav

Sharma

2014

Journal of Experimental Biology

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Insects including the fruit fly Drosophila melanogaster are under intense pressure to develop rapidly because they inhabit ephemeral habitats. We have previously shown that when selection for faster development was artificially imposed on D. melanogaster in the laboratory, reduction of pre-adult development time and shortening of the clock period occurs, suggesting a role for circadian clocks in the regulation of life history traits. Circadian clocks in D. melanogaster have also been implicated in the control of metabolic pathways, ageing processes, oxidative stress and defense responses to exogenous stressors. In order to rigorously examine correlations between pre-adult development time and other life history traits, we assayed pre-adult survivorship, starvation and desiccation resistance, body size and body weight, fecundity and adult lifespan in faster developing populations of D. melanogaster. The results revealed that selection for faster pre-adult development significantly reduced several adult fitness traits in the faster developing flies without affecting pre-adult survivorship. Although overall fecundity of faster developing flies was reduced, their egg output per unit body weight was significantly higher than that of controls, indicating that reduction in adult lifespan might be due to disproportionate investment in reproduction. Thus our results suggest that selection for faster preadult development in D. melanogaster yields flies with higher reproductive fitness. Because these flies also have shorter clock periods, our results can be taken to suggest that pre-adult development time and circadian clock period are correlated with various adult life history traits in D. melanogaster, implying that circadian clocks may have adaptive significance.

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Section: Introductionmentioning

confidence: 74%

Correlated changes in life history traits in response to selection for faster pre-adult development in the fruit fly Drosophila melanogaster

Yadav

Sharma

2014

Journal of Experimental Biology

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“…For example, wild-caught antelope ground squirrels (Ammospermophilus leucurus) deprived of their suprachiasmatic nuclei [SCN, where the master circadian clock is located (Moore & Eichler 1972, Stephan & Zucker 1972] behaved normally but became arrhythmic, enabling nocturnal Mojave Desert predators such as rattlesnakes, kit foxes, bobcats, coyotes, and barn owls to take advantage of their limited visual acuity at night and prey upon them (DeCoursey et al 1997).…”

Section: Adaptations To Nocturnal and Diurnal Activitymentioning

confidence: 99%

Partitioning of Time as an Ecological Resource

Kronfeld‐Schor

Dayan

2003

Annu. Rev. Ecol. Evol. Syst.

770

684

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s Abstract Animal species have evolved different diel activity rhythms that are of adaptive value. Theory suggests that diel temporal partitioning may facilitate coexistence between competitors and between predators and prey. However, relatively few studies demonstrate a temporal shift that is predation-or competition-induced. Recorded shifts are usually within the preferred activity phase of animal species (day or night), although there are some inversions to the opposite phase cycle. Temporal partitioning is not perceived as a common mechanism of coexistence. This rarity has been variously ascribed to theoretical considerations and to the rigidity of time-keeping mechanisms, as well as to other physiological and anatomical traits that may constrain activity patterns. Our decade-long study of spiny mice of rocky deserts demonstrates that, while different factors select for activity patterns, endogenous rhythmicity may be an evolutionary constraint.

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“…Circadian rhythms are observed in organisms ranging from cyanobacteria to humans, and their conservation during evolution suggests that they confer a selective advantage. Indeed, it has been experimentally shown that mutant cyanobacteria with an altered rhythm (16) and ground squirrels with no rhythm (17) were overtaken by their wild-type counterparts either in the test tube or in a simulated field condition. However, the circadian rhythm is not universal: the Archaea and most of the eubacteria display no circadian rhythm, and several model organisms, including Escherichia coli, Saccharomyces cerevisiae, and Schizosaccharomyces pombe, lack circadian rhythms (13).…”

Section: Circadian Rhythmsmentioning

confidence: 99%

Cryptochrome: The Second Photoactive Pigment in the Eye and Its Role in Circadian Photoreception

Sancar

2000

Annu. Rev. Biochem.

243

201

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Key Words blue-light photoreceptor, flavoprotein, retina, suprachiasmatic nucleus, circadian blind mice, seasonal affective disorder s Abstract Circadian rhythms are oscillations in the biochemical, physiological, and behavioral functions of organisms that occur with a periodicity of approximately 24 h. They are generated by a molecular clock that is synchronized with the solar day by environmental photic input. The cryptochromes are the mammalian circadian photoreceptors. They absorb light and transmit the electromagnetic signal to the molecular clock using a pterin and flavin adenine dinucleotide (FAD) as chromophore/cofactors, and are evolutionarily conserved and structurally related to the DNA repair enzyme photolyase. Humans and mice have two cryptochrome genes, CRY1 and CRY2, that are differentially expressed in the retina relative to the opsin-based visual photoreceptors. CRY1 is highly expressed with circadian periodicity in the mammalian circadian pacemaker, the suprachiasmatic nucleus (SCN). Mutant mice lacking either Cry1 or Cry2 have impaired light induction of the clock gene mPer1 and have abnormally short or long intrinsic periods, respectively. The double mutant has normal vision but is defective in mPer1 induction by light and lacks molecular and behavioral rhythmicity in constant darkness. Thus, cryptochromes are photoreceptors and central components of the molecular clock. Genetic evidence also shows that cryptochromes are circadian photoreceptors in Drosophila and Arabidopsis, raising the possibility that they may be universal circadian photoreceptors. Research on cryptochromes may provide new understanding of human diseases such as seasonal affective disorder and delayed sleep phase syndrome. CONTENTS

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Circadian Performance of Suprachiasmatic Nuclei (SCN)-Lesioned Antelope Ground Squirrels in a Desert Enclosure

Cited by 124 publications

References 25 publications

Correlated changes in life history traits in response to selection for faster pre-adult development in the fruit fly Drosophila melanogaster

Correlated changes in life history traits in response to selection for faster pre-adult development in the fruit fly Drosophila melanogaster

Partitioning of Time as an Ecological Resource

Cryptochrome: The Second Photoactive Pigment in the Eye and Its Role in Circadian Photoreception

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