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Lin, C., & Shalitin, D. (2003). Cryptochrome structure and signal transduction. Annu Rev Plant Biol, 54, 469–496.
Abstract: Cryptochromes are photosensory receptors mediating light regulation of growth and development in plants. Since the isolation of the Arabidopsis CRY1 gene in 1993, cryptochromes have been found in every multicellular eukaryote examined. Most plant cryptochromes have a chromophore-binding domain that shares similar structure with DNA photolyase, and a carboxyl terminal extension that contains a DQXVP-acidic-STAES (DAS) domain conserved from moss, to fern, to angiosperm. In Arabidopsis, cryptochromes are nuclear proteins that mediate light control of stem elongation, leaf expansion, photoperiodic flowering, and the circadian clock. Cryptochromes may act by interacting with proteins such as phytochromes, COP1, and clock proteins, or/and chromatin and DNA. Recent studies suggest that cryptochromes undergo a blue light-dependent phosphorylation that affects the conformation, intermolecular interactions, physiological activities, and protein abundance of the photoreceptors.
Keywords: Amino Acid Sequence; Cryptochromes; Cytochromes/metabolism; Deoxyribodipyrimidine Photo-Lyase/genetics; *Drosophila Proteins; *Eye Proteins; Flavoproteins/*chemistry/genetics/physiology; Molecular Sequence Data; Multigene Family; *Photoreceptor Cells, Invertebrate; Plant Physiological Phenomena; Plant Proteins/metabolism; Plants/genetics; Receptors, G-Protein-Coupled; Signal Transduction/*physiology
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Chaves, I., Pokorny, R., Byrdin, M., Hoang, N., Ritz, T., Brettel, K., et al. (2011). The cryptochromes: blue light photoreceptors in plants and animals. Annu Rev Plant Biol, 62, 335–364.
Abstract: Cryptochromes are flavoprotein photoreceptors first identified in Arabidopsis thaliana, where they play key roles in growth and development. Subsequently identified in prokaryotes, archaea, and many eukaryotes, cryptochromes function in the animal circadian clock and are proposed as magnetoreceptors in migratory birds. Cryptochromes are closely structurally related to photolyases, evolutionarily ancient flavoproteins that catalyze light-dependent DNA repair. Here, we review the structural, photochemical, and molecular properties of cry-DASH, plant, and animal cryptochromes in relation to biological signaling mechanisms and uncover common features that may contribute to better understanding the function of cryptochromes in diverse systems including in man.
Keywords: Adenosine Triphosphate/metabolism; Animals; Cryptochromes/chemistry/classification/*physiology; DNA Repair; Deoxyribodipyrimidine Photo-Lyase/chemistry/classification/physiology; Homing Behavior; Insects/physiology; *Light Signal Transduction; Magnetics; Mice; Oxidation-Reduction; Phosphorylation/physiology; Plants/*metabolism
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Beneduci, A., Chidichimo, G., De Rose, R., Filippelli, L., Straface, S. V., & Venuta, S. (2005). Frequency and irradiation time-dependant antiproliferative effect of low-power millimeter waves on RPMI 7932 human melanoma cell line. Anticancer Res, 25(2a), 1023–1028.
Abstract: The biological effects produced by low power millimeter waves (MMW) were studied on the RPMI 7932 human melanoma cell line. Three different frequency-type irradiation modes were used: the 53.57-78.33 GHz wide-band frequency range, the 51.05 GHz and the 65.00 GHz monochromatic frequencies. In all three irradiation conditions, the radiation energy was low enough not to increase the temperature of the cellular samples. Three hours of radiation treatment, applied every day to the melanoma cell samples, were performed at each frequency exposure condition. The wide-band irradiation treatment effectively inhibited cell growth, while both the monochromatic irradiation treatments did not affect the growth trend of RPMI 7932 cells. A light microscopy analysis revealed that the low-intensity wide-band millimeter radiation induced significant morphological alterations on these cells. Furthermore, a histochemical study revealed the low proliferative state of the irradiated cells. This work provides further evidence of the antiproliferative effects on tumor cells induced by low power MMW in the 50-80 GHz frequency range of the electromagnetic spectrum.
Keywords: Cell Line, Tumor; Cell Proliferation/radiation effects; *Electromagnetic Fields; Humans; Light; Melanoma/pathology/*radiotherapy; Microscopy; Microwaves
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Beneduci, A., Chidichimo, G., Tripepi, S., & Perrotta, E. (2005). Transmission electron microscopy study of the effects produced by wide-band low-power millimeter waves on MCF-7 human breast cancer cells in culture. Anticancer Res, 25(2a), 1009–1013.
Abstract: Our previous work showed that low-power wide-band millimeter waves (MMW) inhibit the growth of the MCF-7 human breast carcinoma cell line, also causing a marked reduction of the density of microvilli at the apical membrane of the MCF-7 cells, as revealed by scanning electron microscopy. The aim of the present work was to investigate the ultrastructural changes induced by such electromagnetic radiations on this cell line. A transmission electron microscopy study was performed on MCF-7 cells irradiated under the same experimental conditions previously adopted. Transmission electron microscopy analysis revealed several ultrastructural features of the MMW-irradiated cells pertinent to cells subjected to sublethal injury. The antiproliferative effect of the millimeter radiation was confirmed. MMW, in the 52-78 GHz frequency range, act as stress factor on the cells that survive in a non-steady low-mitogenetic metabolic state.
Keywords: Breast Neoplasms/*radiotherapy/*ultrastructure; Cell Line, Tumor/radiation effects; *Electromagnetic Fields; Humans; Microscopy, Electron, Transmission; Microwaves
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Hirata, M., Kusuzaki, K., Takeshita, H., Hashiguchi, S., Hirasawa, Y., & Ashihara, T. (2001). Drug resistance modification using pulsing electromagnetic field stimulation for multidrug resistant mouse osteosarcoma cell line. Anticancer Res, 21(1a), 317–320.
Abstract: Multidrug resistance (MDR) is one of the major problems in osteosarcoma chemotherapy. Therefore, methods of overcoming MDR are urgently needed. In this study, we investigated the effects of pulsing electromagnetic field stimulation (PEMFs) on a MDR murine osteosarcoma cell line which strongly expresses P-glycoprotein (P-gp). To assess the reversal effects of PEMFs on doxorubicin (DOX) resistance, MTT assay was applied. Viable cells were assessed by the trypan blue exclusion test. Fluorescence intensity of DOX binding to nuclear DNA of each cell was measured using a cytofluorometer. Changes in P-gp expression in each cell were detected by the indirect immunofluorescence method using an antibody to Pgp. PEMFs increased DOX binding ability to nuclear DNA and inhibited cell growth, although it had no significant effect on P-gp expression. These findings indicated that PEMFs reversed the DOX resistance of the MOS/ADR1 cells by inhibiting P-gp function. The results suggested that PEMFs may be useful as a local treatment for MDR osteosarcoma.
Keywords: Animals; Antineoplastic Agents/metabolism/*therapeutic use; Bone Neoplasms/drug therapy/metabolism/*therapy; Cell Division/drug effects; Cell Nucleus/drug effects/metabolism; Combined Modality Therapy; DNA, Neoplasm/drug effects/metabolism; Doxorubicin/metabolism/*therapeutic use; *Drug Resistance, Multiple; Drug Resistance, Neoplasm; *Electromagnetic Fields; Mice; Microscopy, Fluorescence; Osteosarcoma/drug therapy/metabolism/*therapy; P-Glycoprotein/metabolism; Tumor Cells, Cultured
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