Photoperiod

Publication Title: 
Plant Cell Reports

Resistant rootstocks offer an alternative to pesticides for the control of soil pests. In Prunus spp., resistance loci to root-knot nematodes (RKN) have been mapped and a transformation method is needed to validate candidate genes. Our efforts have focused on the generation of transformed hairy-roots and composite plants appropriate for nematode infection assays. An efficient and reliable method using the A4R strain of Agrobacterium rhizogenes for the transformation of Prunus roots with an Egfp reporter gene is given.

Author(s): 
Bosselut, Nathalie
Van Ghelder, Cyril
Claverie, Michel
Voisin, Roger
Onesto, Jean-Paul
Rosso, Marie-Noëlle
Esmenjaud, Daniel
Publication Title: 
PLoS genetics

Organisms perceive changes in their dietary environment and enact a suite of behavioral and metabolic adaptations that can impact motivational behavior, disease resistance, and longevity. However, the precise nature and mechanism of these dietary responses is not known. We have uncovered a novel link between dietary factors and sleep behavior in Drosophila melanogaster.

Author(s): 
Linford, Nancy J.
Chan, Tammy P.
Pletcher, Scott D.
Publication Title: 
Journal of Biological Rhythms

Sleep inertia is the impaired cognitive performance immediately upon awakening, which decays over tens of minutes. This phenomenon has relevance to people who need to make important decisions soon after awakening, such as on-call emergency workers. Such awakenings can occur at varied times of day or night, so the objective of the study was to determine whether or not the magnitude of sleep inertia varies according to the phase of the endogenous circadian cycle. Twelve adults (mean, 24 years; 7 men) with no medical disorders other than mild asthma were studied.

Author(s): 
Scheer, Frank A. J. L.
Shea, Thomas J.
Hilton, Michael F.
Shea, Steven A.
Publication Title: 
Science Translational Medicine

In humans, modulation of circadian rhythms by light is thought to be mediated primarily by melanopsin-containing retinal ganglion cells, not rods or cones. Melanopsin cells are intrinsically blue light-sensitive but also receive input from visual photoreceptors. We therefore tested in humans whether cone photoreceptors contribute to the regulation of circadian and neuroendocrine light responses.

Author(s): 
Gooley, Joshua J.
Rajaratnam, Shantha M. W.
Brainard, George C.
Kronauer, Richard E.
Czeisler, Charles A.
Lockley, Steven W.
Publication Title: 
PloS One

OBJECTIVE: To examine the time-of-day and Ramadan fasting (RF) effects on serum apolipoprotein-AI (Apo-AI) and B (Apo-B), lipoprotein particles-a (Lp-a), high-sensitive C-reactive-protein (hs-CRP), and homocysteine (Hcy) during the Yo-Yo intermittent recovery test (YYIRT). DESIGN: Performance and biochemical measures were completed at two times-of-day (07:00 and 17:00 h), 1-week before RF (BR), the second week of RF (SWR), and the fourth week of RF (ER).

Author(s): 
Hammouda, Omar
Chtourou, Hamdi
Aloui, Asma
Chahed, Henda
Kallel, Choumous
Miled, Abdelhedi
Chamari, Karim
Chaouachi, Anis
Souissi, Nizar
Publication Title: 
Biology of Reproduction

Short day lengths or reduced food availability are salient cues for small mammals that breed seasonally. Photoperiod-mediated gonadal regression in white-footed mice (Peromyscus leucopus) is a slow, orderly process that involves testicular apoptosis. Testicular regression in response to restricted caloric intake is relatively rapid, and it is generally reversed quickly by ad libitum (ad lib) feeding.

Author(s): 
Young, K. A.
Zirkin, B. R.
Nelson, R. J.
Publication Title: 
American Journal of Physiology. Heart and Circulatory Physiology

Caloric restriction of mammals leads to decreases in blood pressure and heart rate. Although relevant clinically, the mechanisms involved, in terms of hormones and signaling pathways invoked, are currently not known. Circumstantial evidence suggests that leptin signaling may be involved with the bradycardia and hypotension associated with caloric restriction. This hypothesis was specifically tested using leptin-deficient mice (ob/ob) or leptin-receptor rats (Koletsky). Ob/ob mice were hypertensive during the light cycle relative to littermate controls (108 +/- 2 vs.

Author(s): 
Swoap, S. J.
Publication Title: 
Biology of Reproduction

Caloric restriction and hormone treatment delay reproductive senescence in female mammals, but a natural model of decelerated reproductive aging does not presently exist. In addition to describing such a model, this study shows that an abiotic signal (photoperiod) can induce physiological changes that slow senescence. Relative to animals born in April, rodents born in September delay their first reproductive effort by up to 7 mo, at which age reduced fertility is expected.

Author(s): 
Place, Ned J.
Tuthill, Christiana R.
Schoomer, Elanor E.
Tramontin, Anthony D.
Zucker, Irving
Publication Title: 
Hormones and Behavior

Measures of arousal were used to study effects of estradiol and food restriction, and their potential interactions, in ovariectomized female C57Bl/6 mice. It was hypothesized based on a proposed theoretical equation [Pfaff, D.W., 2006a. Brain Arousal and Information Theory. Harvard University Press, Cambridge, Pfaff, D.W., (Ed.), 2006b. Knobil and Neill's The Physiology of Reproduction, 3rd edition. Elsevier/Academic Press, San Diego] that each treatment would increase arousal-related behaviors and that their combination would further increase arousal behavior.

Author(s): 
Shelley, Deborah N.
Dwyer, Evarose
Johnson, Carolyn
Wittkowski, Knut M.
Pfaff, Donald W.
Publication Title: 
PloS One

OBJECTIVE: To examine the time-of-day and Ramadan fasting (RF) effects on serum apolipoprotein-AI (Apo-AI) and B (Apo-B), lipoprotein particles-a (Lp-a), high-sensitive C-reactive-protein (hs-CRP), and homocysteine (Hcy) during the Yo-Yo intermittent recovery test (YYIRT). DESIGN: Performance and biochemical measures were completed at two times-of-day (07:00 and 17:00 h), 1-week before RF (BR), the second week of RF (SWR), and the fourth week of RF (ER).

Author(s): 
Hammouda, Omar
Chtourou, Hamdi
Aloui, Asma
Chahed, Henda
Kallel, Choumous
Miled, Abdelhedi
Chamari, Karim
Chaouachi, Anis
Souissi, Nizar

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