Blue mussels, Mytilus edulis , form dense beds of both commercial and ecological importance, and many attempts have been made to determine their filtration rate. The total time in which mussels actually utilise their ...Blue mussels, Mytilus edulis , form dense beds of both commercial and ecological importance, and many attempts have been made to determine their filtration rate. The total time in which mussels actually utilise their filtration capacity in nature varies greatly, making in situ methods for filtration rate measurements relevant. Further, it is being debated to what extend filtration rates measured in the laboratory using cultivated algal cells may apply for mussels in nature. In the present study, we have used an open-top chamber setup in order to allow repeated in situ filtration rate measurements of M. edulis using ambient natural phytoplankton and free-living bacteria. We found that the in situ measured filtration rates are comparable to filtration rates obtained in laboratory studies using different methods and controlled diets of cultivated algal cells. Further, we found that the retention efficiency of free-living bacteria was between 22.2% and 29.9%, in good agreement with values from laboratory studies. Our findings support the assumption that mussels in nature tend to use their filtration capacity when the phytoplankton concentration is above a certain lower trigger level.展开更多
Background Pigment epithelium-derived factor （PEDF） is expressed in several normal organs and identified as an inhibitor of neovascularization. In the present study, we investigated the effect of PEDF in an in vitro...Background Pigment epithelium-derived factor （PEDF） is expressed in several normal organs and identified as an inhibitor of neovascularization. In the present study, we investigated the effect of PEDF in an in vitro model of ocular choroidal neovascularization. Methods Microdissection was used to isolate the human choroidal endothelial cells （CECs）, followed by the use of superparamagnetic beads （Dynabeads） coated with the CD31 antibody, which selectively binds to the endothelial cell surface. The mitogenic and motogenic effects of vascular endothelial growth factor （VEGF） on cultured choroidal capillary endothelial cells were examined in the presence or absence of PEDF （1, 10, 100, and 1000 ng/ml） using cell counts and migration assays. Results Cells bound to the beads were isolated using a magnetic particle concentrator and they were successfully cultured and characterized to be endothelial cells that possessed greater than 95% immunoreactivity to von Willebrand factor. PEDF suppressed the proliferation and migration of VEGF-induced choroidal capillary endothelial cells. However, the concentration of PEDF which we used has little effect on normal CECs. Conclusions PEDF played an important role on the growth and migration of VEGF-stimulated choroidal endothelial cell These findings suggest that PEDF may be an effective approach to the treatment of choroidal neovascular disorders.展开更多
基金supported by a research grant(9278)from VILLUM FONDEN
文摘Blue mussels, Mytilus edulis , form dense beds of both commercial and ecological importance, and many attempts have been made to determine their filtration rate. The total time in which mussels actually utilise their filtration capacity in nature varies greatly, making in situ methods for filtration rate measurements relevant. Further, it is being debated to what extend filtration rates measured in the laboratory using cultivated algal cells may apply for mussels in nature. In the present study, we have used an open-top chamber setup in order to allow repeated in situ filtration rate measurements of M. edulis using ambient natural phytoplankton and free-living bacteria. We found that the in situ measured filtration rates are comparable to filtration rates obtained in laboratory studies using different methods and controlled diets of cultivated algal cells. Further, we found that the retention efficiency of free-living bacteria was between 22.2% and 29.9%, in good agreement with values from laboratory studies. Our findings support the assumption that mussels in nature tend to use their filtration capacity when the phytoplankton concentration is above a certain lower trigger level.
基金grants from Shanghai Science and Technology Committee "Qi Ming Xing" Project (No.02QB14037)Youth Foundation of Shanghai Jiao Tong University, School of Medicine(No. 040202).
文摘Background Pigment epithelium-derived factor （PEDF） is expressed in several normal organs and identified as an inhibitor of neovascularization. In the present study, we investigated the effect of PEDF in an in vitro model of ocular choroidal neovascularization. Methods Microdissection was used to isolate the human choroidal endothelial cells （CECs）, followed by the use of superparamagnetic beads （Dynabeads） coated with the CD31 antibody, which selectively binds to the endothelial cell surface. The mitogenic and motogenic effects of vascular endothelial growth factor （VEGF） on cultured choroidal capillary endothelial cells were examined in the presence or absence of PEDF （1, 10, 100, and 1000 ng/ml） using cell counts and migration assays. Results Cells bound to the beads were isolated using a magnetic particle concentrator and they were successfully cultured and characterized to be endothelial cells that possessed greater than 95% immunoreactivity to von Willebrand factor. PEDF suppressed the proliferation and migration of VEGF-induced choroidal capillary endothelial cells. However, the concentration of PEDF which we used has little effect on normal CECs. Conclusions PEDF played an important role on the growth and migration of VEGF-stimulated choroidal endothelial cell These findings suggest that PEDF may be an effective approach to the treatment of choroidal neovascular disorders.
