Browsing by Subject "circadian rhythms"

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    Effect of Light–Dark Cycle on Skin Mucosal Immune Activities of Gilthead Seabream (Sparus aurata) and European Sea Bass (Dicentrarchus labrax)
    (MDPI, 2020) Ceballos-Francisco, Diana; Cuesta Peñafiel, Alberto; Esteban Abad, María de los Ángeles; Biología Celular e Histología
    Changes in di erent immune activities in the skin mucus of gilthead seabream (Sparus aurata L.) and European sea bass (Dicentrarchus labrax L.) specimens exposed to a constant light–dark photoperiod (12 h L:12 h D) were studied. Samples were collected at 08:00 (light on), 14:00, 20:00 (light o ), 02:00, and again at 08:00 to determine immunoglobulin M (IgM) levels, several enzymes related to the immune system, and bactericidal activity. IgM levels were higher during the day in seabream and reached a minimum value at 20:00, but it was hardly a ected in sea bass. No significant variations were recorded in the levels of protease and antiprotease. Peroxidase reached its maximum level in seabream at 02:00, the same time that it reached its minimum level in sea bass. Lysozyme showed little variation in seabream, but it was significantly lower at 14:00 than during the rest of the cycle in sea bass. Finally, di erent interspecific variations on bactericidal activity against Vibrio harveyi were recorded. The findings demonstrate that the immune parameters present in skin mucus of these important fish species are a ected by the light–dark cycle and that there are substantial interspecies di erences.
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    Light-induced rhythmic changes in thermotolerance in stationary-phase cells of Candida utilis
    (International microbiology : the official journal of the Spanish Society for Microbiology., 2006) Lapeña, Miguel A.; Vicente, Jero; Soto, Teresa; Madrid, Marisa; Núñez, Andrés; García, Encarnación; Cansado Vizoso, José; Gacto, Mariano; Genética y Microbiología
    In synchronized light-dark cycles, stationary-phase cultures of the budding yeast Candida utilis were able to survive heat treatment at 50ºC with an apparent circadian-like rhythm related to the onset of light. However, in continuous darkness this pattern did not run freely and was markedly dampened. We discuss these findings in terms of the potential circadian control of heat tolerance, which has been described in the fission yeast Schizosaccharomyces pombe. Our results suggest that the resistance pattern observed in C. utilis is most likely an adaptive response to the light-induced generation of reactive oxygen species rather than the occurrence of a truly endogenous circadian rhythm