The most obvious symptom of Al toxicity is the inhibition of root growth. However, the mechanism of Al-inhibiting root growth remains to be elucidated. In this study, auxin transport and vesicle movement of an auxin-e...The most obvious symptom of Al toxicity is the inhibition of root growth. However, the mechanism of Al-inhibiting root growth remains to be elucidated. In this study, auxin transport and vesicle movement of an auxin-efflux carrier (PIN2) were investigated in Arabidopsis roots in response to Al stress. Results indicated that Al inhibited the apical transport of auxin in root tips of Arabidopsis significantly. The severe inhibition was localized in the cells of transition zone, where the concentration of auxin was only 34% that of the control. Brefeldin A (BFA), an inhibitor of vesicle transport, induced the dot-like structure of PIN2 vesicle significantly. Al decreased the size of dot-like structure of PIN2 vesicles. Re- sults of real-time RT-PCR and Western-blotting analysis showed that Al increased the transcript level of PIN2 and the accumulation of PIN2 protein in horizontal direction of plasma membrane, but decreased its distribution in endosomes, suggesting that Al inhibited the transport of PIN2 vesicles from plasma membrane to endosomes. Results of cytoskeleton-depolymering drugs indicated that it was via the pathway of disruption of actin microfilaments that Al inhibited the transport of PIN2 vesicles. Exposed to Al stress, the cells of elongation zone had less Al uptake and less transport frequency of vesicles than cells of transition zone. Taken together, our results suggested that Al inhibited root growth mainly by modulating the transport of PIN2 vesicles between plasma membrane and endosomes, thus block- ing auxin transport and root growth.展开更多
Geodetic applications of Low Earth Orbit(LEO)satellites requires accurate satellite orbits.Instead of using onboard Global Navigation Satellite System observations,this contribution treats the LEO satellite constellat...Geodetic applications of Low Earth Orbit(LEO)satellites requires accurate satellite orbits.Instead of using onboard Global Navigation Satellite System observations,this contribution treats the LEO satellite constellation independently,using Inter-Satellite Links and the measurements of different ground networks.Due to geopolitical and geographical reasons,a ground station network cannot be well distributed.We compute the impact of different ground networks(i.e.,global networks with different numbers of stations and regional networks in different areas and latitudes)on LEO satellite orbit determination with and without the inter-satellite links.The results are based on a simulated constellation of 90 LEO satellites.We find that the orbits determined using a high latitude network is worse than using a middle or low latitude network.This is because the high latitude network has a poorer geometry even if the availability of satellite measurements is higher than for the other two cases.Also,adding more stations in a regional network shows almost no improvements on the satellite orbits if the number of stations is more than 16.With the help of ISL observations,however,the satellite orbits determined with a small regional network can reach the same accuracy as that with the global network of 60 stations.Furthermore,satellite biases can be well estimated(less than 0.6 mm)and have nearly no impact on satellite orbits.It does thus not matter if they are not physically calibrated for estimating precise orbits.展开更多
Current stem cell protocols for ischemic heart disease are limited by the smal l numbers of cells that can be obtained by bone marrow aspirate. To increase myo cardial delivery of bone marrow stem cells in patients wi...Current stem cell protocols for ischemic heart disease are limited by the smal l numbers of cells that can be obtained by bone marrow aspirate. To increase myo cardial delivery of bone marrow stem cells in patients with chronic ischemic hea rt disease(CIHD), we used granulocyte colony stimulating factor(G-CSF) for bone marrow mobilization of CD34+cells, enabling intracoronary infusion of large nu mbers of CD34+stem cells. Patients with CIHD(n=5) demonstrated significantly re duced numbers of CD34+cells mobilized by G-CSF in comparison to age-matched c ontrols. Sustained reduction in anginal symptoms and improvement in quality of l ife scores was seen in all patients following infusion of cells. Moreover, mean collateral flow grade at 12-month follow-up angiography significantly improved , indicating sustained myocardial neovascularization. No proliferative retinopat hy was induced and no in-stent restenosis seen. However, in two patients with d ocumented increase in collateral flow, complications arose, one developing an ac ute coronary syndrome and the other a lentigo maligna. These results demonstrate the feasibility of G-CSF mobilization, leukapheresis and intracoronary transfe r of CD34+stem cells in patients with CIHD, but longer-term studies are requir ed to ensure that this protocol is safe and effective.展开更多
Background: Cutaneous leishmaniasis (CL) is rare in Northern Europe and may be overlooked because colleagues have little experience with it. Objectives: To identify manifestations of CL that may escape diagnosis. Meth...Background: Cutaneous leishmaniasis (CL) is rare in Northern Europe and may be overlooked because colleagues have little experience with it. Objectives: To identify manifestations of CL that may escape diagnosis. Methods: Correlation of clinical diagnosis and histopathological findings in 28 biopsy specimens taken from 19 patients with CL confirmed by polymerase chain reaction (PCR) specific for Leishmania. Results: In only one patient was the clinical diagnosis CL; other diagnoses included: malignant epithelial neoplasms (5), follicular cyst (2), atypical mycobacteriosis (1), sarcoidosis (2) and lymphoma (1). Lesions were single (15) or few (4) nodules predominantly situated on the extremities or face (16). Histopathological findings were diagnostic of CL in only 10 cases. In nine cases Leishmania was not identified microscopically; histopathological diagnoses were: granulomatous dermatitis (6), lupoid rosacea (1), foreign body granuloma (1) and granuloma annulare (1). Unaltered epidermis (9), nodular infiltrates (5), numerous multinucleated histiocytes (3), palisaded granulomas with fibrinoid centres (2), sarcoidal granulomas (4) and elastophagocytosis (1) misled the histopathologists in these cases. Conclusions: CL seems often to be misdiagnosed clinically in countries where it is not endemic. Histopathologically, CL may be misinterpreted as sarcoidosis, foreign body granuloma, lupoid rosacea and granuloma annulare, especially when Leishmania is not seen microscopically. We suggest that in Northern Europe, PCR for Leishmania-specific DNA should be performed routinely in any granulomatous dermatitis presenting as a single or few nodules on the extremities or face, even when a diagnosis of CL was not considered by the referring clinician.展开更多
基金the National Natural Science Foundation of China (Grant Nos. 30771294 and 30471040)the International Foundation for Science of Sweden (Grant Nos. C/3042-1,2), and the DAAD (Ref423)
文摘The most obvious symptom of Al toxicity is the inhibition of root growth. However, the mechanism of Al-inhibiting root growth remains to be elucidated. In this study, auxin transport and vesicle movement of an auxin-efflux carrier (PIN2) were investigated in Arabidopsis roots in response to Al stress. Results indicated that Al inhibited the apical transport of auxin in root tips of Arabidopsis significantly. The severe inhibition was localized in the cells of transition zone, where the concentration of auxin was only 34% that of the control. Brefeldin A (BFA), an inhibitor of vesicle transport, induced the dot-like structure of PIN2 vesicle significantly. Al decreased the size of dot-like structure of PIN2 vesicles. Re- sults of real-time RT-PCR and Western-blotting analysis showed that Al increased the transcript level of PIN2 and the accumulation of PIN2 protein in horizontal direction of plasma membrane, but decreased its distribution in endosomes, suggesting that Al inhibited the transport of PIN2 vesicles from plasma membrane to endosomes. Results of cytoskeleton-depolymering drugs indicated that it was via the pathway of disruption of actin microfilaments that Al inhibited the transport of PIN2 vesicles. Exposed to Al stress, the cells of elongation zone had less Al uptake and less transport frequency of vesicles than cells of transition zone. Taken together, our results suggested that Al inhibited root growth mainly by modulating the transport of PIN2 vesicles between plasma membrane and endosomes, thus block- ing auxin transport and root growth.
基金Federal Ministry of Economic Affairs and Climate Action(BMWi)based on a resolution of the German Bundestag under the code 50 NA 1706.
文摘Geodetic applications of Low Earth Orbit(LEO)satellites requires accurate satellite orbits.Instead of using onboard Global Navigation Satellite System observations,this contribution treats the LEO satellite constellation independently,using Inter-Satellite Links and the measurements of different ground networks.Due to geopolitical and geographical reasons,a ground station network cannot be well distributed.We compute the impact of different ground networks(i.e.,global networks with different numbers of stations and regional networks in different areas and latitudes)on LEO satellite orbit determination with and without the inter-satellite links.The results are based on a simulated constellation of 90 LEO satellites.We find that the orbits determined using a high latitude network is worse than using a middle or low latitude network.This is because the high latitude network has a poorer geometry even if the availability of satellite measurements is higher than for the other two cases.Also,adding more stations in a regional network shows almost no improvements on the satellite orbits if the number of stations is more than 16.With the help of ISL observations,however,the satellite orbits determined with a small regional network can reach the same accuracy as that with the global network of 60 stations.Furthermore,satellite biases can be well estimated(less than 0.6 mm)and have nearly no impact on satellite orbits.It does thus not matter if they are not physically calibrated for estimating precise orbits.
文摘Current stem cell protocols for ischemic heart disease are limited by the smal l numbers of cells that can be obtained by bone marrow aspirate. To increase myo cardial delivery of bone marrow stem cells in patients with chronic ischemic hea rt disease(CIHD), we used granulocyte colony stimulating factor(G-CSF) for bone marrow mobilization of CD34+cells, enabling intracoronary infusion of large nu mbers of CD34+stem cells. Patients with CIHD(n=5) demonstrated significantly re duced numbers of CD34+cells mobilized by G-CSF in comparison to age-matched c ontrols. Sustained reduction in anginal symptoms and improvement in quality of l ife scores was seen in all patients following infusion of cells. Moreover, mean collateral flow grade at 12-month follow-up angiography significantly improved , indicating sustained myocardial neovascularization. No proliferative retinopat hy was induced and no in-stent restenosis seen. However, in two patients with d ocumented increase in collateral flow, complications arose, one developing an ac ute coronary syndrome and the other a lentigo maligna. These results demonstrate the feasibility of G-CSF mobilization, leukapheresis and intracoronary transfe r of CD34+stem cells in patients with CIHD, but longer-term studies are requir ed to ensure that this protocol is safe and effective.
文摘Background: Cutaneous leishmaniasis (CL) is rare in Northern Europe and may be overlooked because colleagues have little experience with it. Objectives: To identify manifestations of CL that may escape diagnosis. Methods: Correlation of clinical diagnosis and histopathological findings in 28 biopsy specimens taken from 19 patients with CL confirmed by polymerase chain reaction (PCR) specific for Leishmania. Results: In only one patient was the clinical diagnosis CL; other diagnoses included: malignant epithelial neoplasms (5), follicular cyst (2), atypical mycobacteriosis (1), sarcoidosis (2) and lymphoma (1). Lesions were single (15) or few (4) nodules predominantly situated on the extremities or face (16). Histopathological findings were diagnostic of CL in only 10 cases. In nine cases Leishmania was not identified microscopically; histopathological diagnoses were: granulomatous dermatitis (6), lupoid rosacea (1), foreign body granuloma (1) and granuloma annulare (1). Unaltered epidermis (9), nodular infiltrates (5), numerous multinucleated histiocytes (3), palisaded granulomas with fibrinoid centres (2), sarcoidal granulomas (4) and elastophagocytosis (1) misled the histopathologists in these cases. Conclusions: CL seems often to be misdiagnosed clinically in countries where it is not endemic. Histopathologically, CL may be misinterpreted as sarcoidosis, foreign body granuloma, lupoid rosacea and granuloma annulare, especially when Leishmania is not seen microscopically. We suggest that in Northern Europe, PCR for Leishmania-specific DNA should be performed routinely in any granulomatous dermatitis presenting as a single or few nodules on the extremities or face, even when a diagnosis of CL was not considered by the referring clinician.
