The chloroplast is surrounded by a double-membrane envelope at which proteins, ions, and numerous metabolites including nucleotides, amino acids, fatty acids, and carbohydrates are exchanged between the two aqueous ph...The chloroplast is surrounded by a double-membrane envelope at which proteins, ions, and numerous metabolites including nucleotides, amino acids, fatty acids, and carbohydrates are exchanged between the two aqueous phases, the cytoplasm and the chloroplast stroma. The chloroplast envelope is also the location where the biosynthesis and accumulation of various lipids take place. By contrast to the inner membrane, which contains a number of specific transporters and acts as the permeability barrier, the chloroplast outer membrane has often been considered a passive compartment derived from the phagosomal membrane. However, the presence of galactoglycerolipids and β-barrel membrane proteins support the common origin of the outer membranes of the chloroplast envelope and extant cyanobacteria. Furthermore, recent progress in the field underlines that the chloroplast outer envelope plays important roles not only for translocation of various molecules, but also for regulation of metabolic activities and signaling processes. The chloroplast outer envelope membrane offers various interesting and challenging questions that are relevant to the understanding of organelle biogenesis, plant growth and development, and also membrane biology in general.展开更多
The major Rhesus （Rh） protein of the green alga Chlamydomonas reinhardtii, Rhl, is homologous to Rh proteins of humans. It is an integral membrane protein involved in transport of carbon dioxide. To localize a fusio...The major Rhesus （Rh） protein of the green alga Chlamydomonas reinhardtii, Rhl, is homologous to Rh proteins of humans. It is an integral membrane protein involved in transport of carbon dioxide. To localize a fusion of intact Rhl to the green fluorescent protein （GFP）, we used as host a white （Its1） mutant strain of C. reinhardtii, which is blocked at the first step of carotenoid biosynthesis. The Its1 mutant strain accumulated normal amounts of Rhl heterotrophically in the dark and Rhl-GFP was at the periphery of the cell co-localized with the cytoplasmic membrane dye FM4-64. Although Rhl carries a potential chloroplast targeting sequence at its N-terminus, Rhl-GFP was clearly not associated with the chloroplast envelope membrane. Moreover, the N-terminal half of the protein was not imported into chloroplasts in vitro and N-terminal regions of Rhl did not direct import of the small subunit of ribulose bisphosphate carboxylase （SSU）. Despite caveats to this interpretation, which we discuss, current evidence indicates that Rhl is a cytoplasmic membrane protein and that Rhl-GFP is among the first cytoplasmic membrane protein fusions to be obtained in C. reinhardtii. Although Its1 （white） mutant strains cannot be used to localize proteins within sub-compartments of the chloroplast because they lack thylakoid membranes, they should nonetheless be valuable for localizing many GFP fusions in Chlamydomonas.展开更多
Objective:No ideal training system exists for pancreaticoduodenectomy(PD).We developed an educational system that uses an objective structured assessment of technical skills.Methods:This retrospective observational st...Objective:No ideal training system exists for pancreaticoduodenectomy(PD).We developed an educational system that uses an objective structured assessment of technical skills.Methods:This retrospective observational study was conducted using the data of consecutive trainees and patients who underwent PD from 2007 to 2013 in Kansai Medical University Hospital.The total score on the task checklist(21 parameters)for measuring technical performance during PD by self assessment and instructor assessment was compared between junior(JN)and hepatobiliary pancreatic(HBP)trainees at a university hospital.Surgical outcomes of 303 PDs(2007-2013)were also compared among JN trainees,HBP trainees,and instructors,and the present position of the trainees was investigated.This study was approved by the institutional review board of Kansai Medical University on May 26,2020.Results:The self-assessment score on the task checklist was significantly higher for the HBP trainees than for the JN trainees on all parts of PD(P<.001).The discrepancy between self-assessment and instructor assessment improved in 3 JN trainees after experience with the first 5 PDs.Although total score curves rose to the right in the JN group,scores in the HBP group were stable,at 70 or higher,which correlated with the instructor assessment.The 90-day and 30-day mortality rates were 1.6%and 0.3%,respectively.Mortality and morbidity after PD did not differ between the JN and HBP trainees or between the instructors and the trainees.Four of 10 trainees became board-certified expert surgeons of the Japanese Society of Hepatobiliary Pancreatic Surgery.Conclusion:These results indicated good construct validity of the task checklist system.This program was safely and effectively implemented in terms of surgical outcomes and final outcomes of trainees becoming board-certified expert surgeons.展开更多
文摘The chloroplast is surrounded by a double-membrane envelope at which proteins, ions, and numerous metabolites including nucleotides, amino acids, fatty acids, and carbohydrates are exchanged between the two aqueous phases, the cytoplasm and the chloroplast stroma. The chloroplast envelope is also the location where the biosynthesis and accumulation of various lipids take place. By contrast to the inner membrane, which contains a number of specific transporters and acts as the permeability barrier, the chloroplast outer membrane has often been considered a passive compartment derived from the phagosomal membrane. However, the presence of galactoglycerolipids and β-barrel membrane proteins support the common origin of the outer membranes of the chloroplast envelope and extant cyanobacteria. Furthermore, recent progress in the field underlines that the chloroplast outer envelope plays important roles not only for translocation of various molecules, but also for regulation of metabolic activities and signaling processes. The chloroplast outer envelope membrane offers various interesting and challenging questions that are relevant to the understanding of organelle biogenesis, plant growth and development, and also membrane biology in general.
文摘The major Rhesus （Rh） protein of the green alga Chlamydomonas reinhardtii, Rhl, is homologous to Rh proteins of humans. It is an integral membrane protein involved in transport of carbon dioxide. To localize a fusion of intact Rhl to the green fluorescent protein （GFP）, we used as host a white （Its1） mutant strain of C. reinhardtii, which is blocked at the first step of carotenoid biosynthesis. The Its1 mutant strain accumulated normal amounts of Rhl heterotrophically in the dark and Rhl-GFP was at the periphery of the cell co-localized with the cytoplasmic membrane dye FM4-64. Although Rhl carries a potential chloroplast targeting sequence at its N-terminus, Rhl-GFP was clearly not associated with the chloroplast envelope membrane. Moreover, the N-terminal half of the protein was not imported into chloroplasts in vitro and N-terminal regions of Rhl did not direct import of the small subunit of ribulose bisphosphate carboxylase （SSU）. Despite caveats to this interpretation, which we discuss, current evidence indicates that Rhl is a cytoplasmic membrane protein and that Rhl-GFP is among the first cytoplasmic membrane protein fusions to be obtained in C. reinhardtii. Although Its1 （white） mutant strains cannot be used to localize proteins within sub-compartments of the chloroplast because they lack thylakoid membranes, they should nonetheless be valuable for localizing many GFP fusions in Chlamydomonas.
文摘Objective:No ideal training system exists for pancreaticoduodenectomy(PD).We developed an educational system that uses an objective structured assessment of technical skills.Methods:This retrospective observational study was conducted using the data of consecutive trainees and patients who underwent PD from 2007 to 2013 in Kansai Medical University Hospital.The total score on the task checklist(21 parameters)for measuring technical performance during PD by self assessment and instructor assessment was compared between junior(JN)and hepatobiliary pancreatic(HBP)trainees at a university hospital.Surgical outcomes of 303 PDs(2007-2013)were also compared among JN trainees,HBP trainees,and instructors,and the present position of the trainees was investigated.This study was approved by the institutional review board of Kansai Medical University on May 26,2020.Results:The self-assessment score on the task checklist was significantly higher for the HBP trainees than for the JN trainees on all parts of PD(P<.001).The discrepancy between self-assessment and instructor assessment improved in 3 JN trainees after experience with the first 5 PDs.Although total score curves rose to the right in the JN group,scores in the HBP group were stable,at 70 or higher,which correlated with the instructor assessment.The 90-day and 30-day mortality rates were 1.6%and 0.3%,respectively.Mortality and morbidity after PD did not differ between the JN and HBP trainees or between the instructors and the trainees.Four of 10 trainees became board-certified expert surgeons of the Japanese Society of Hepatobiliary Pancreatic Surgery.Conclusion:These results indicated good construct validity of the task checklist system.This program was safely and effectively implemented in terms of surgical outcomes and final outcomes of trainees becoming board-certified expert surgeons.
