Coral bleaching has generally been recognized as the main reason for tropical coral reef degradation, but there are few long-term records of coral bleaching events. In this study, trace metals including chromium(Cr), ...Coral bleaching has generally been recognized as the main reason for tropical coral reef degradation, but there are few long-term records of coral bleaching events. In this study, trace metals including chromium(Cr), copper(Cu), molybdenum(Mo), manganese(Mn), lead(Pb), tin(Sn), titanium(Ti), vanadium(V), and yttrium(Y), were analyzed in two Porites corals collected from Meiji Reef in the tropical South China Sea(SCS) to assess differences in trace metal concentrations in bleached compared with unbleached coral growth bands. Ti, V, Cr, and Mo generally showed irregular fluctuations in both corals. Bleached layers contained high concentrations of Mn, Cu, Sn, and Pb. Unbleached layers showed moderately high concentrations of Mn and Cu only. The different distribution of trace metals in Porites may be attributable to different selectivity on the basis of vital utility or toxicity. Ti, V, Cr, and Mo are discriminated against by both coral polyps and zooxanthellae, but Mn, Cu, Sn, and Pb are accumulated by zooxanthellae and only Mn and Cu are accumulated by polyps as essential elements. The marked increase in Cu, Mn, Pb, and Sn are associated with bleaching processes, including mucus secretion, tissue retraction, and zooxanthellae expulsion and occlusion. Variation in these trace elements within the coral skeleton can be used as potential tracers of short-lived bleaching events.展开更多
To investigate if hyperbaric oxygen (HBO) may induce structural changes of neurons in hippocampus from infantile rats and if the changes are reversible. Methods: All 27 healthy SD infantile rats were exposed to HBO ( ...To investigate if hyperbaric oxygen (HBO) may induce structural changes of neurons in hippocampus from infantile rats and if the changes are reversible. Methods: All 27 healthy SD infantile rats were exposed to HBO ( 0.25 MPa) or hyperbaric air (HBA) for 1 to 3 courses (10 days as 1 course). The hippocampus was taken at the end of each course to observe its morphology by light microscope and electron microscope. Results: HBO exposure induced capillary dilation, nuclear membrane winding or blurring and some mitochondria swelling with its crista blurring in neurons. The changes occurred after 1 course exposure and became significant with time. Most of the changes recovered 20 days after stopping exposure. No change was found after HBA exposure. Conclusions: Long-term HBO exposure can cause capillary dilation and ultrastructural injury of neurons in hippocampus from infantile rats. The damage is not serious, but reversible.展开更多
基金Supported by the National Basic Research Program of China(973 Program)(No.2013CB956103)the National Science Foundation of China(Nos.41306109,41476038)
文摘Coral bleaching has generally been recognized as the main reason for tropical coral reef degradation, but there are few long-term records of coral bleaching events. In this study, trace metals including chromium(Cr), copper(Cu), molybdenum(Mo), manganese(Mn), lead(Pb), tin(Sn), titanium(Ti), vanadium(V), and yttrium(Y), were analyzed in two Porites corals collected from Meiji Reef in the tropical South China Sea(SCS) to assess differences in trace metal concentrations in bleached compared with unbleached coral growth bands. Ti, V, Cr, and Mo generally showed irregular fluctuations in both corals. Bleached layers contained high concentrations of Mn, Cu, Sn, and Pb. Unbleached layers showed moderately high concentrations of Mn and Cu only. The different distribution of trace metals in Porites may be attributable to different selectivity on the basis of vital utility or toxicity. Ti, V, Cr, and Mo are discriminated against by both coral polyps and zooxanthellae, but Mn, Cu, Sn, and Pb are accumulated by zooxanthellae and only Mn and Cu are accumulated by polyps as essential elements. The marked increase in Cu, Mn, Pb, and Sn are associated with bleaching processes, including mucus secretion, tissue retraction, and zooxanthellae expulsion and occlusion. Variation in these trace elements within the coral skeleton can be used as potential tracers of short-lived bleaching events.
文摘To investigate if hyperbaric oxygen (HBO) may induce structural changes of neurons in hippocampus from infantile rats and if the changes are reversible. Methods: All 27 healthy SD infantile rats were exposed to HBO ( 0.25 MPa) or hyperbaric air (HBA) for 1 to 3 courses (10 days as 1 course). The hippocampus was taken at the end of each course to observe its morphology by light microscope and electron microscope. Results: HBO exposure induced capillary dilation, nuclear membrane winding or blurring and some mitochondria swelling with its crista blurring in neurons. The changes occurred after 1 course exposure and became significant with time. Most of the changes recovered 20 days after stopping exposure. No change was found after HBA exposure. Conclusions: Long-term HBO exposure can cause capillary dilation and ultrastructural injury of neurons in hippocampus from infantile rats. The damage is not serious, but reversible.
