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Articoli di riviste sul tema "Photoperiodism"

Autore: Grafiati

Pubblicato: 4 giugno 2021

Ultima modifica: 28 luglio 2024

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1

Lorincz, Annaka M., M. Benjamin Shoemaker e Paul D. Heideman. "Genetic variation in photoperiodism among naturally photoperiodic rat strains". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 281, n. 6 (1 dicembre 2001): R1817—R1824. http://dx.doi.org/10.1152/ajpregu.2001.281.6.r1817.

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Rattus norvegicus has been considered nonphotoperiodic, but Fischer 344 (F344) rats are inhibited in growth and reproductive development by short photoperiod (SD). We tested photoresponsiveness of the genetically divergent Brown Norway (BN) strain of rats. Peripubertal males were tested in long photoperiod or SD, with or without 30% food reduction. Young males were photoresponsive, with reductions in testis size, body mass, and food intake in SD and with enhanced responses to SD when food restricted. Photoperiods ≤11 h of light inhibited reproductive maturation and somatic growth, whereas photoperiods of 12 h or more produced little or no response. F344/BN hybrids differ from both parent strains in the timing, amplitude, and critical photoperiod of photoperiodic responses, indicating genetic differences in photoperiodism between these strains. This is consistent with the hypothesis that ancestors of laboratory rats were genetically variable for photoperiodism and that different combinations of alleles for photoperiodism have been fixed in different strains of rats.

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2

Brainard, George C., John P. Hanifin, Felix M. Barker, Britt Sanford e Milton H. Stetson. "Influence of near-ultraviolet radiation on reproductive and immunological development in juvenile male Siberian hamsters". Journal of Experimental Biology 204, n. 14 (15 luglio 2001): 2535–41. http://dx.doi.org/10.1242/jeb.204.14.2535.

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SUMMARY The aim of this study was to characterize the lenticular ultraviolet transmission of the Siberian hamster (Phodopus sungorus) and to probe the range of near-ultraviolet (UV-A, 315–400nm) and visible wavelengths (400–760nm) for modulating the photoperiodic regulation of its reproductive and immune systems. Ocular lenses from adult hamsters were found to transmit UV-A wavelengths at similar levels to visible wavelengths, with a short-wavelength cut-off of 300nm. Five separate studies compared the responses of juvenile male hamsters to long photoperiods (16h:8h L:D), short photoperiods (10h:14h L:D) and short photoperiods interrupted by an equal photon pulse of monochromatic light of 320, 340, 360, 500 or 725nm during the night. The results show that UV-A wavelengths at 320, 340 and 360nm can regulate both reproductive and immune short-photoperiod responses as effectively as visible monochromatic light at 500nm. In contrast, long-wavelength visible light at 725nm did not block the short-photoperiod responses. These results suggest that both wavelengths in the visible spectrum, together with UV-A wavelengths, contribute to hamster photoperiodism in natural habitats.

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Siddiqi, Shoaib Ahmad, Shakira Aslam, Mona Hassan, Naureen Naeem e Shazia Bokhari. "Response of Different Species of Plants Towards Photoperiodism". Lahore Garrison University Journal of Life Sciences 2, n. 2 (22 aprile 2020): 153–69. http://dx.doi.org/10.54692/lgujls.2018.010227.

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Different plants respond to photoperiod in diverse manners. There are three major types of the responses of photoperiodism in plants: short-day responses (SD), long-day responses (LD) and dayneutral responses (DN). The LD plants flower most rapidly under high intensity of light provided for a large period of time while the short day plants flower rapidly only if light is provided for a short period of time. The plants with day-neutral responses, does not depends on the conditions of photoperiod in order to flower. Every plant behaves according to the length of light on its own way. In this study the plants that were considered shows distinct responses. Lettuce (Lactuca sativa), for example responded towards longday photoperiod. Synthetic hexaploids showed a slight photoperiodic response of Triricum turgidum rather than the accessions of Triticum tauschii. Tomato (Solanum Lycopersicum) showed a day neutral response but some modern tomatoes had mild short day response towards photoperiodism. The tuberization in potato (Solanum tuberosum) was favored by short day photoperiodic response as well as cool temperature.

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4

Lankinen, Pekka, Chedly Kastally e Anneli Hoikkala. "Nanda-Hamner Curves Show Huge Latitudinal Variation but No Circadian Components in Drosophila Montana Photoperiodism". Journal of Biological Rhythms 36, n. 3 (22 marzo 2021): 226–38. http://dx.doi.org/10.1177/0748730421997265.

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Insect species with a wide distribution offer a great opportunity to trace latitudinal variation in the photoperiodic regulation of traits important in reproduction and stress tolerances. We measured this variation in the photoperiodic time-measuring system underlying reproductive diapause in Drosophila montana, using a Nanda-Hamner (NH) protocol. None of the study strains showed diel rhythmicity in female diapause proportions under a constant day length (12 h) and varying night lengths in photoperiods ranging from 16 to 84 h at 16°C. In the northernmost strains (above 55°N), nearly all females entered diapause under all photoperiods and about half of them even in continuous darkness, while the females of the southern strains showed high diapause proportions only in the circadian 24 h photoperiod. Significant correlation between the strains’ mean diapause proportions in ≥ 24 h photoperiods and critical day length (CDL; half of the females enter diapause) suggests at least partial causal connection between the traits. Interestingly, females of the northern strains entered diapause even in ≤ 24 h photoperiods, where the night length was shorter than their critical night length (24 h - CDL), but where the females experienced a higher number of Light:Dark cycles than in 24 h photoperiods. NH experiments, performed on the control and selection lines in our previous selection experiment, and completed here, gave similar results and confirmed that selection for shorter, southern-type CDL decreases female diapausing rate in non-circadian photoperiods. Overall, our study shows that D. montana females measure night length quantitatively, that the photoperiodic counter may play a prominent but slightly different role in extra short and extra long photoperiods and that northern strains show high stability against perturbations in the photoperiod length and in the presence of LD cycles. These features are best explained by the quantitative versions of the damped external coincidence model.

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5

Saunders, David S. "Dormancy, Diapause, and the Role of the Circadian System in Insect Photoperiodism". Annual Review of Entomology 65, n. 1 (7 gennaio 2020): 373–89. http://dx.doi.org/10.1146/annurev-ento-011019-025116.

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Whole-animal experiments devised to investigate possible association between photoperiodic time measurement and the circadian system (Bünning's hypothesis) are compared with more recent molecular investigations of circadian clock genes. In Sarcophaga argyrostoma and some other species, experimental cycles of light and darkness revealed a photoperiodic oscillator, set to constant phase at dusk and measuring night length repeatedly during extended periods of darkness. In some species, however, extreme dampening revealed an unrepetitive (i.e., hourglass-like) response. Rhythms of clock gene transcript abundance may also show similar phase relationships to the light cycle, and gene silencing of important clock genes indicates that they play a crucial role in photoperiodism either alone or in concert. However, the multiplicity of peripheral oscillators in the insect circadian system indicates that more complex mechanisms might also be important.

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6

Iiams, Samantha E., Aldrin B. Lugena, Ying Zhang, Ashley N. Hayden e Christine Merlin. "Photoperiodic and clock regulation of the vitamin A pathway in the brain mediates seasonal responsiveness in the monarch butterfly". Proceedings of the National Academy of Sciences 116, n. 50 (25 novembre 2019): 25214–21. http://dx.doi.org/10.1073/pnas.1913915116.

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Seasonal adaptation to changes in light:dark regimes (i.e., photoperiod) allows organisms living at temperate latitudes to anticipate environmental changes. In nearly all animals studied so far, the circadian system has been implicated in measurement and response to the photoperiod. In insects, genetic evidence further supports the involvement of several clock genes in photoperiodic responses. Yet, the key molecular pathways linking clock genes or the circadian clock to insect photoperiodic responses remain largely unknown. Here, we show that inactivating the clock in the North American monarch butterfly using loss-of-function mutants for the circadian activators CLOCK and BMAL1 and the circadian repressor CRYPTOCHROME 2 abolishes photoperiodic responses in reproductive output. Transcriptomic approaches in the brain of monarchs raised in long and short photoperiods, summer monarchs, and fall migrants revealed a molecular signature of seasonal-specific rhythmic gene expression that included several genes belonging to the vitamin A pathway. We found that the rhythmic expression of these genes was abolished in clock-deficient mutants, suggesting that the vitamin A pathway operates downstream of the circadian clock. Importantly, we showed that a CRISPR/Cas9-mediated loss-of-function mutation in the gene encoding the pathway’s rate-limiting enzyme, ninaB1, abolished photoperiod responsiveness independently of visual function in the compound eye and without affecting circadian rhythms. Together, these results provide genetic evidence that the clock-controlled vitamin A pathway mediates photoperiod responsiveness in an insect. Given previously reported seasonal changes associated with this pathway in the mammalian brain, our findings suggest an evolutionarily conserved function of vitamin A in animal photoperiodism.

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7

Markovskaya, E. F., e M. I. Sysoeva. "EVOLUTION OF PLANT PHOTOPERIODISM". Acta Horticulturae, n. 907 (settembre 2011): 189–92. http://dx.doi.org/10.17660/actahortic.2011.907.27.

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8

Kryvyi, V. V., e O. Y. Martsinyuk. "Photoperiodism in poultry farming". Taurian Scientific Herald, n. 122 (2021): 208–13. http://dx.doi.org/10.32851/2226-0099.2021.122.30.

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9

EBIHARA, Shizufumi, Shinobu YASUO e Takashi YOSHIMURA. "Mechanisms of Vertebrate Photoperiodism". Seibutsu Butsuri 45, n. 4 (2005): 185–91. http://dx.doi.org/10.2142/biophys.45.185.

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10

Provencio, I. "Shedding light on photoperiodism". Proceedings of the National Academy of Sciences 107, n. 36 (27 agosto 2010): 15662–63. http://dx.doi.org/10.1073/pnas.1010370107.

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11

Tan, Ying, Martha Merrow e Till Roenneberg. "Photoperiodism in Neurospora Crassa". Journal of Biological Rhythms 19, n. 2 (aprile 2004): 135–43. http://dx.doi.org/10.1177/0748730404263015.

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12

Bradshaw, William E., e Christina M. Holzapfel. "Evolution of Animal Photoperiodism". Annual Review of Ecology, Evolution, and Systematics 38, n. 1 (dicembre 2007): 1–25. http://dx.doi.org/10.1146/annurev.ecolsys.37.091305.110115.

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13

Jackson, Stephen. "Photoperiodism. The biological calendar". Annals of Botany 108, n. 7 (novembre 2011): vi. http://dx.doi.org/10.1093/aob/mcr215.

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14

Xia, Zhengjun, Hong Zhai, Shixiang Lü, Hongyan Wu e Yupeng Zhang. "Recent Achievement in Gene Cloning and Functional Genomics in Soybean". Scientific World Journal 2013 (2013): 1–7. http://dx.doi.org/10.1155/2013/281367.

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Soybean is a model plant for photoperiodism as well as for symbiotic nitrogen fixation. However, a rather low efficiency in soybean transformation hampers functional analysis of genes isolated from soybean. In comparison, rapid development and progress in flowering time and photoperiodic response have been achieved inArabidopsisand rice. As the soybean genomic information has been released since 2008, gene cloning and functional genomic studies have been revived as indicated by successfully characterizing genes involved in maturity and nematode resistance. Here, we review some major achievements in the cloning of some important genes and some specific features at genetic or genomic levels revealed by the analysis of functional genomics of soybean.

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15

Roenneberg, Till, e Martha Merrow. "Seasonality and Photoperiodism in Fungi". Journal of Biological Rhythms 16, n. 4 (agosto 2001): 403–14. http://dx.doi.org/10.1177/074873001129001999.

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16

SAUNDERS, DAVID S. "Insect photoperiodism: seeing the light". Physiological Entomology 37, n. 3 (8 giugno 2012): 207–18. http://dx.doi.org/10.1111/j.1365-3032.2012.00837.x.

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17

Saunders, D. S. "Insect photoperiodism: Measuring the night". Journal of Insect Physiology 59, n. 1 (gennaio 2013): 1–10. http://dx.doi.org/10.1016/j.jinsphys.2012.11.003.

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18

Kamphuisen, H. A. C. "Photoperiodism, melatonin and the pineal". Journal of the Neurological Sciences 74, n. 1 (giugno 1986): 121–22. http://dx.doi.org/10.1016/0022-510x(86)90197-8.

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19

Bastow, Ruth, e Caroline Dean. "The Molecular Basis of Photoperiodism". Developmental Cell 3, n. 4 (ottobre 2002): 461–62. http://dx.doi.org/10.1016/s1534-5807(02)00296-4.

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20

Heap, R. B. "Photoperiodism, melatonin and the pineal". Molecular and Cellular Endocrinology 50, n. 3 (aprile 1987): 269–70. http://dx.doi.org/10.1016/0303-7207(87)90026-8.

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21

Jarillo, Jose A., e Manuel A. Piñeiro. "The molecular basis of photoperiodism". Biological Rhythm Research 37, n. 4 (agosto 2006): 353–80. http://dx.doi.org/10.1080/09291010600804619.

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22

Saunders, D. S. "Insect circadian rhythms and photoperiodism". Invertebrate Neuroscience 3, n. 2-3 (settembre 1997): 155–64. http://dx.doi.org/10.1007/bf02480370.

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23

Ebihara, Shizufumi, Shinobu Yasuo, Nobuhiro Nakao e Takashi Yoshimura. "Molecular mechanisms of vertebrate photoperiodism". Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 148, n. 3 (novembre 2007): 338. http://dx.doi.org/10.1016/j.cbpb.2007.07.020.

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24

Reekie, J. Y. C., P. R. Hicklenton e E. G. Reekie. "Effects of elevated CO2 on time of flowering in four short-day and four long-day species". Canadian Journal of Botany 72, n. 4 (1 aprile 1994): 533–38. http://dx.doi.org/10.1139/b94-071.

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This study was undertaken to determine if the effect of elevated CO2 on flowering phenology is a function of the photoperiodic response of the species involved. Four long-day plants, Achillea millefolium, Callistephus chinensis, Campanula isophylla, and Trachelium caeruleum, and four short-day plants, Dendranthema grandiflora, Kalanchoe blossfeldiana, Pharbitis nil, and Xanthium pensylvanicum, were grown under inductive photoperiods (9 h for short day and 17 h for long day) at either 350 or 1000 μL/L CO2. Time of visible flower bud formation, flower opening, and final plant biomass were assessed. Elevated CO2 advanced flower opening in all four long-day species and delayed flowering in all four short-day species. In the long-day species, the effect of CO2 was primarily on bud initiation; all four species formed buds earlier at high CO2. Bud development, the difference in time between flower opening and bud initiation, was advanced in only one long-day species, Callistephus chinensis. Mixed results were obtained for the short-day species. Elevated CO2 exerted no effects on bud initiation but delayed bud development in Dendranthema and Kalanchoe. In Xanthium, bud initiation rather than bud development was delayed. Data on bud initiation and development were not obtained for Pharbitis. The negative effect of CO2 upon phenology in the short-day species was not associated with negative effects on growth. Elevated CO2 increased plant size in both long-day and short-day species. Key words: phenology, bud initiation, flower opening, size at flowering, photoperiodism.

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25

Hasebe, Masaharu, e Sakiko Shiga. "Clock gene-dependent glutamate dynamics in the bean bug brain regulate photoperiodic reproduction". PLOS Biology 20, n. 9 (6 settembre 2022): e3001734. http://dx.doi.org/10.1371/journal.pbio.3001734.

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Animals adequately modulate their physiological status and behavior according to the season. Many animals sense photoperiod for seasonal adaptation, and the circadian clock is suggested to play an essential role in photoperiodic time measurement. However, circadian clock-driven neural signals in the brain that convey photoperiodic information remain unclear. Here, we focused on brain extracellular dynamics of a classical neurotransmitter glutamate, which is widely used for brain neurotransmission, and analyzed its involvement in photoperiodic responses using the bean bug Riptortus pedestris that shows clear photoperiodism in reproduction. Extracellular glutamate levels in the whole brain were significantly higher under short-day conditions, which cause a reproductive diapause, than those under long-day conditions. The photoperiodic change in glutamate levels was clearly abolished by knockdown of the clock gene period. We also demonstrated that genetic modulation of glutamate dynamics by knockdown of glutamate-metabolizing enzyme genes, glutamate oxaloacetate transaminase (got) and glutamine synthetase (gs), attenuated photoperiodic responses in reproduction. Further, we investigated glutamate-mediated photoperiodic modulations at a cellular level, focusing on the pars intercerebralis (PI) neurons that photoperiodically change their neural activity and promote oviposition. Electrophysiological analyses showed that L-Glutamate acts as an inhibitory signal to PI neurons via glutamate-gated chloride channel (GluCl). Additionally, combination of electrophysiology and genetics revealed that knockdown of got, gs, and glucl disrupted cellular photoperiodic responses of the PI neurons, in addition to reproductive phenotypes. Our results reveal that the extracellular glutamate dynamics are photoperiodically regulated depending on the clock gene and play an essential role in the photoperiodic control of reproduction via inhibitory pathways.

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26

Ma, Hong. "Flowering time: From photoperiodism to florigen". Current Biology 8, n. 19 (settembre 1998): R690—R692. http://dx.doi.org/10.1016/s0960-9822(98)70437-3.

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Samach, Alon, e Ayala Gover. "Photoperiodism: The consistent use of CONSTANS". Current Biology 11, n. 16 (agosto 2001): R651—R654. http://dx.doi.org/10.1016/s0960-9822(01)00384-0.

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28

Sheely, Catherine, e Samer Hattar. "Breaking the rules: Atypical photoreceptors with diverse functions". Biochemist 33, n. 6 (1 dicembre 2011): 6–9. http://dx.doi.org/10.1042/bio03306006.

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As the Earth rotates around its axis, the Sun illuminates different parts of the planet with varied strengths and amounts of light exposure. Primary producers, from unicellular cyanobacteria to redwood trees, harness the light energy and provide the basis for food chains in the Earth's ecosystems. Light, however, has other functions that are important for survival, which include phototaxis in unicellular organisms, measuring day length (photoperiodism) in plants and animals, and vision. Although the eye is a highly specialized organ that contains the photoreceptive machinery to mediate vision, organisms such as fish, birds and lizards rely on extraocular photoreceptors to co-ordinate long-term effects of light, including synchronization of daily rhythms to the solar day, photoperiodic measurements and hormonal regulation. Mammals, however, rely solely on the eyes and a specialized photoreceptive neuronal structure, the retina, to receive all light information for image and non-image forming visual functions.

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29

Ahmadi, Hamid, Royce S. Bringhurst e Victor Voth. "Modes of Inheritance of Photoperiodism in Fragaria". Journal of the American Society for Horticultural Science 115, n. 1 (gennaio 1990): 146–52. http://dx.doi.org/10.21273/jashs.115.1.146.

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Genetic analysis of day-neutral (photo-insensitive) cultivars and their derivatives hybridized to standard short-day clones of octoploid strawberries [Fragaria × ananassa Duchn., F. chiloensis (L.) Duchn., and F. virginiana glauca Staudt., x = 7, 2n = 56] revealed that photo-insensitivity is controlled by a single dominant allele of a Mendelian gene. The dominant genetic trait is expressed in hybrids with other Fragaria spp. Intergeneric hybrids of day-neutral Fragaria and short-day Potentilla glandulosa L. and P. fruticosa L. also express photo-insensitivity. The day-neutral genes in European perpetual flowering (photo-insensitive) diploid `Alpine' F. vesca (2N = 14) apparently have evolved independently, since photo-insensitivity is recessive to photo-sensitivity. Native California diploid F. vesca have diverged considerably from European F. vesca. No photo-insensitive diploids have been found among them. Photo-sensitivity in native California F. vesca is controlled by three dominant genes. The origins of day-neutral cultivars of F. × ananassa and the classification of day-neutrality are discussed.

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Davis, Seth J. "Photoperiodism: The Coincidental Perception of the Season". Current Biology 12, n. 24 (dicembre 2002): R841—R843. http://dx.doi.org/10.1016/s0960-9822(02)01348-9.

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Silverin, Bengt. "Photoperiodism in male great tits (Parus major)". Ethology Ecology & Evolution 6, n. 2 (luglio 1994): 131–57. http://dx.doi.org/10.1080/08927014.1994.9522990.

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Gallot, Aurore, Claude Rispe, Nathalie Leterme, Jean-Pierre Gauthier, Stéphanie Jaubert-Possamai e Denis Tagu. "Cuticular proteins and seasonal photoperiodism in aphids". Insect Biochemistry and Molecular Biology 40, n. 3 (marzo 2010): 235–40. http://dx.doi.org/10.1016/j.ibmb.2009.12.001.

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Abrieux, Antoine, Yongbo Xue, Yao Cai, Kyle M. Lewald, Hoang Nhu Nguyen, Yong Zhang e Joanna C. Chiu. "EYES ABSENT and TIMELESS integrate photoperiodic and temperature cues to regulate seasonal physiology inDrosophila". Proceedings of the National Academy of Sciences 117, n. 26 (15 giugno 2020): 15293–304. http://dx.doi.org/10.1073/pnas.2004262117.

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Abstract (sommario):

Organisms possess photoperiodic timing mechanisms to detect variations in day length and temperature as the seasons progress. The nature of the molecular mechanisms interpreting and signaling these environmental changes to elicit downstream neuroendocrine and physiological responses are just starting to emerge. Here, we demonstrate that, inDrosophila melanogaster, EYES ABSENT (EYA) acts as a seasonal sensor by interpreting photoperiodic and temperature changes to trigger appropriate physiological responses. We observed that tissue-specific genetic manipulation ofeyaexpression is sufficient to disrupt the ability of flies to sense seasonal cues, thereby altering the extent of female reproductive dormancy. Specifically, we observed that EYA proteins, which peak at night in short photoperiod and accumulate at higher levels in the cold, promote reproductive dormancy in femaleD. melanogaster. Furthermore, we provide evidence indicating that the role of EYA in photoperiodism and temperature sensing is aided by the stabilizing action of the light-sensitive circadian clock protein TIMELESS (TIM). We postulate that increased stability and level of TIM at night under short photoperiod together with the production of cold-induced and light-insensitive TIM isoforms facilitate EYA accumulation in winter conditions. This is supported by our observations thattimnull mutants exhibit reduced incidence of reproductive dormancy in simulated winter conditions, while flies overexpressingtimshow an increased incidence of reproductive dormancy even in long photoperiod.

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Hoole, C., A. E. McKechnie, D. M. Parker e N. C. Bennett. "The influence of photoperiod on the reproductive physiology of the greater red musk shrew (Crociduraflavescens)". Canadian Journal of Zoology 94, n. 3 (marzo 2016): 163–68. http://dx.doi.org/10.1139/cjz-2015-0128.

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Photoperiodism involves the use of both absolute measures of day length and the direction in which day length is changing as a cue for regulating seasonal changes in physiology and behaviour so that birth and lactation coincide with optimal resource availability, increasing offspring survival. Induced ovulation and opportunistic breeding is often found in species that are predominantly solitary and territorial. In this study, the photoperiodic reproductive responses of male greater red musk shrews (Crocidura flavescens (I. Geoffroy Saint-Hilaire, 1827)) were investigated in the laboratory. The presence of spermatozoa regardless of the light cycle, suggest that although the shrews are photoresponsive, they may be capable of breeding throughout the year. Significantly greater testicular volume and seminiferous tubule diameter following exposure to a short day-light cycle suggests that these animals may have breeding peaks that correspond to short days. The presence of epidermal spines on the penis indicates that the shrew is likely also an induced ovulator. Flexible breeding patterns combined with induced ovulation affords this solitary species the greatest chance of reproductive success.

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Shiga, Sakiko, e Hideharu Numata. "Neuroanatomical Approaches to the Study of Insect Photoperiodism†". Photochemistry and Photobiology 83, n. 1 (26 febbraio 2007): 76–86. http://dx.doi.org/10.1562/2006-03-31-ir-863.

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Ball, Gregory F. "Thyroid Hormone Transport and Photoperiodism: Feeling One’s Oatps". Endocrinology 147, n. 3 (marzo 2006): 1065–66. http://dx.doi.org/10.1210/en.2005-1520.

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Tauber, Eran, e Bambos Panayiotis Kyriacou. "Insect Photoperiodism and Circadian Clocks: Models and Mechanisms". Journal of Biological Rhythms 16, n. 4 (agosto 2001): 381–90. http://dx.doi.org/10.1177/074873001129002088.

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Goto, Shin G. "Roles of circadian clock genes in insect photoperiodism". Entomological Science 16, n. 1 (4 dicembre 2012): 1–16. http://dx.doi.org/10.1111/ens.12000.

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SHIMIZU, Isamu. "Voltinism and photoperiodism of the silkworm, Bombyx mori." Japanese journal of applied entomology and zoology 35, n. 1 (1991): 83–91. http://dx.doi.org/10.1303/jjaez.35.83.

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Hazlerigg, David G., e Gabriela C. Wagner. "Seasonal photoperiodism in vertebrates: from coincidence to amplitude". Trends in Endocrinology & Metabolism 17, n. 3 (aprile 2006): 83–91. http://dx.doi.org/10.1016/j.tem.2006.02.004.

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41

Saunders, D. S. "Controversial aspects of photoperiodism in insects and mites". Journal of Insect Physiology 56, n. 11 (novembre 2010): 1491–502. http://dx.doi.org/10.1016/j.jinsphys.2010.05.002.

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42

Keller, Franziska, e Christian Körner. "The Role of Photoperiodism in Alpine Plant Development". Arctic, Antarctic, and Alpine Research 35, n. 3 (agosto 2003): 361–68. http://dx.doi.org/10.1657/1523-0430(2003)035[0361:tropia]2.0.co;2.

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43

SAUNDERS, David. "Insect photoperiodism: Seasonal development on a revolving planet". European Journal of Entomology 117 (10 agosto 2020): 328–42. http://dx.doi.org/10.14411/eje.2020.038.

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44

Butler, Matthew P., Kevin W. Turner, Jin Ho Park, James P. Butler, Justin J. Trumbull, Sean P. Dunn, Philip Villa e Irving Zucker. "Simulated natural day lengths synchronize seasonal rhythms of asynchronously born male Siberian hamsters". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 293, n. 1 (luglio 2007): R402—R412. http://dx.doi.org/10.1152/ajpregu.00146.2007.

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Abstract (sommario):

Photoperiodism research has relied on static day lengths and abrupt transitions between long and short days to characterize the signals that drive seasonal rhythms. To identify ecologically relevant critical day lengths and to test the extent to which naturally changing day lengths synchronize important developmental events, we monitored nine cohorts of male Siberian hamsters ( Phodopus sungorus) born every 2 wk from 4 wk before to 12 wk after the summer solstice in a simulated natural photoperiod (SNP). SNP hamsters born from 4 wk before to 2 wk after the solstice underwent rapid somatic and gonadal growth; among those born 4–6 wk after the solstice, some delayed puberty by many weeks, whereas others manifested early puberty. Hamsters born eight or more weeks after the solstice failed to undergo early testicular development. The transition to delayed development occurred at long day lengths, which induce early puberty when presented as static photoperiods. The first animals to delay puberty may do so predominantly on the basis of postnatal decreases in day length, whereas in later cohorts, a comparison of postnatal day length to gestational day length may contribute to arrested development. Despite differences in timing of birth and timing of puberty, autumn gonadal regression and spring gonadal and somatic growth occurred at similar calendar dates in all cohorts. Incrementally changing photoperiods exert a strong organizing effect on seasonal rhythms by providing hamsters with a richer source of environmental timing cues than are available in simple static day lengths.

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45

Kumar, Sudhir, Kuldeep Kumar, Rahul Kumar, Jyotishree Pandey, Pritee Sagar, Meenal Rathore e Awnindra Kumar Singh. "Screening for days to Flowering and Photo Insensitivity in Vigna mungo". Ecology, Environment and Conservation 29 (2023): S7—S11. http://dx.doi.org/10.53550/eec.2023.v29i01s.002.

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Abstract (sommario):

Earliness and photo insensitivity is a crucial factor for accommodation of crops in different cropping systems across different agro ecological zones. In the current study we used a core set of 98 genotypes consisting of germplasm as well as released varieties of blackgram to screen it for its response to photoperiodism. Data on days to first flowering and days to fifty percent flowering (DFF) was noted for the individual lines in all the three seasons (Kharif, late kharif, and zaid). An absolute mean difference for days to flowering in all possible combinations and mean of all absolute mean differences were calculated. The core set of genotypes display a huge difference in days to flowering, and thus their differential response to photoperiodism. The set of genotypes were further categorized into early, medium and late flowering according to the mean number of days required for flowering. A total of 32 early, 21 medium, and 2 late flowering lines were identified and were common across both season and years. Similarly, 13 photoperiod insensitive and 8 photoperiod sensitive lines were identified for further validation and studies.

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46

Grevstad, Fritzi S., e Leonard B. Coop. "The consequences of photoperiodism for organisms in new climates". Ecological Applications 25, n. 6 (settembre 2015): 1506–17. http://dx.doi.org/10.1890/14-2071.1.

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47

MARCUS, NANCY H. "Introduction to the Symposium: Photoperiodism in the Marine Environment". American Zoologist 26, n. 2 (maggio 1986): 387–88. http://dx.doi.org/10.1093/icb/26.2.387.

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48

MARCUS, NANCY H. "Population Dynamics of Marine Copepods: The Importance of Photoperiodism". American Zoologist 26, n. 2 (maggio 1986): 469–77. http://dx.doi.org/10.1093/icb/26.2.469.

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49

Bittman, E. L., T. J. Bartness, B. D. Goldman e G. J. DeVries. "Suprachiasmatic and paraventricular control of photoperiodism in Siberian hamsters". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 260, n. 1 (1 gennaio 1991): R90—R101. http://dx.doi.org/10.1152/ajpregu.1991.260.1.r90.

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Abstract (sommario):

The effects of lesions of the suprachiasmatic (SCN) and paraventricular nuclei (PVN) of the hypothalamus on photoperiodic responses were examined in adult Siberian hamsters. SCN lesions reduced nocturnal water intake in long days, whereas PVN lesions increased body weight and food intake in both short and long days. SCN or PVN lesions blocked short-day-induced decreases in body, fat pad, and testes weights and in food intake. Serum prolactin (PRL), but not follicle-stimulating hormone, levels were increased. The distribution of immunostained neurons and fibers for gonadotropin-releasing hormone (GnRH), beta-endorphin, arginine vasopressin (AVP), and vasoactive intestinal polypeptide (VIP) resembled that of other rodent species. Short-day exposure reduced AVP staining in lateral septum, medial amygdala, and bed nucleus of the stria terminalis but not in the PVN of the thalamus or the SCN. Short-day-exposed hamsters had fewer beta-endorphin-positive arcuate nucleus cells and tended to have fewer GnRH-positive preoptic cells than long-day controls. VIP staining was unaffected by photoperiod. Most day length effects on immunostaining were eliminated by either lesion. These results establish the importance of the SCN and PVN in the photoperiodic control of several seasonal responses in Siberian hamsters.

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50

Lofts, B., e C. J. F. Coombs. "Photoperiodism and the testicular refractory period in the mallard". Proceedings of the Zoological Society of London 146, n. 1 (7 maggio 2010): 44–54. http://dx.doi.org/10.1111/j.1469-7998.1965.tb05199.x.

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