The growth of molluscan shell crystals is generally thought to be initiated from the extrapallial fluid by matrix proteins, however, the cellular mechanisms of shell formation pathway remain unknown. Here, we first report amorphous calcium carbonate (ACC) precipitation by cellular biomineralization in primary mantle cell cultures of Pinctada fucata. Through real-time PCR and western blot analyses, we demonstrate that mantle cells retain the ability to synthesize and secrete ACCBP, Pif80 and nacrein in vitro.
View Article and Find Full Text PDFWe report a unique shell margin that differed from the usual shell structure of Pinctada fucata. We observed empty organic envelopes in the prismatic layer and the formation of the nacreous layer in the shell margin. All the characteristics of the growing margin indicated that the shell was growing rapidly.
View Article and Find Full Text PDFPretreatment with 43 nM (10 ng/mL) to 86 nM melatonin for 5 days significantly attenuated cold-induced apoptosis in carrot suspension cells (Daucus carota L.) as evidenced by the TUNEL procedure, DNA fragmentation and the morphological changes revealed by electronic microscopy observations. The antiapoptotic effect of melatonin was initially thought to be a result of its antioxidant actions.
View Article and Find Full Text PDFIn this study, the effect of EGb 761, a standard extract of Ginkgo biloba leaf, on thymocyte apoptosis and age-related thymic atrophy and on peripheral immune dysfunctions was investigated in mice. When primary culture of thymocytes was preincubated with 100 microg/ml EGb 761 before their exposure to hydroxyl radicals (*OH) generated by Fe(2+)-mediated Fenton reaction, apoptotic cell death induced by *OH was distinctly prevented as determined by DNA laddering, the TUNEL assay and flow cytometric analysis. Furthermore, oral EGb 761 administration (about 1.
View Article and Find Full Text PDFThe effect of melatonin on age-related thymic involution and peripheral immune dysfunctions was investigated. Exogenous melatonin was administered through the drinking water (15 microg/ml) of 22-month-old female C57BL mice for 60 consecutive days. Our results show that melatonin distinctly reversed the age-related thymic involution as revealed by the notable increase of thymus weight, total number of thymocytes and percentage of thymocytes at G2+S phases.
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