Diatoms rely on fucoxanthin chlorophyll a/c-binding proteins(FCPs)for light harvesting and energy quenching under marine environments.Here we report two cryo-electron microscopic structures of photosystem I(PSI)with e...Diatoms rely on fucoxanthin chlorophyll a/c-binding proteins(FCPs)for light harvesting and energy quenching under marine environments.Here we report two cryo-electron microscopic structures of photosystem I(PSI)with either 13 or five fucoxanthin chlorophyll a/c-binding protein Is(FCPIs)at 2.78 and 3.20Åresolutions from Thalassiosira pseudonana grown under high light(HL)conditions.Among them,five FCPIs are stably associated with the PSI core,these include Lhcr3,RedCAP,Lhcq8,Lhcf10,and FCP3.The eight additional Lhcr-type FCPIs are loosely associated with the PSI core and detached under the present purification conditions.The pigments of this centric diatom showed a higher proportion of chlorophylls a,diadinoxanthins,and diatoxanthins;some of the chlorophyll as and diadinoxanthins occupy the locations of fucoxanthins found in the huge PSI-FCPI from another centric diatom Chaetoceros gracilis grown under low-light conditions.These additional chlorophyll as may form more energy transfer pathways and additional diadinoxanthins may form more energy dissipation sites relying on the diadinoxanthin-diatoxanthin cycle.These results reveal the assembly mechanism of FCPIs and corresponding light-adaptive strategies of T.pseudonana PSI-FCPI,as well as the convergent evolution of the diatom PSI-FCPI structures.展开更多
AIM: To observe the effects of the different extents of internal limiting membrane(ILM) peeling on the surgical success and anatomical and functional outcomes of idiopathic macular hole(IMH).METHODS: In this retrospec...AIM: To observe the effects of the different extents of internal limiting membrane(ILM) peeling on the surgical success and anatomical and functional outcomes of idiopathic macular hole(IMH).METHODS: In this retrospective cohort study, 36 patients were reviewed and divided into two groups according to the extent of ILM peeling: group A(18 patients), with the peeling area within one-half of the optic disc macular distance as the radius;group B(18 patients), with the peeling area larger than that of group A but did not exceed the optic disc macular distance as the radius. The main outcomes included the best corrected visual acuity(BCVA), light-adaptive electroretinography, macular hole(MH) closure rate, central macular thickness(CMT), retinal nerve fiber layer(RNFL) and ganglion cell complex(GCC) thickness [nine regions based on the Early Treatment of Diabetic Retinopathy Study(ETDRS) ring] before and 1, 3, and 6mo after surgery.RESULTS: The closure rate was 94.4%(17/18) both in groups A and B. The BCVA in both groups improved significantly compared with the preoperative values, but there was no difference between the two groups. The b-wave amplitude of the electroretinogram analysis was significantly improved in both groups compared to that of the preoperative period, with a greater increase in group A than in group B at 6mo(P=0.017). The CMT in both groups gradually decreased after surgery, and there was no difference between the two groups. The RNFL thickness of the temporal outer ring region in group B was significantly lower than that in group A at 3 and 6mo after surgery(P=0.010, 0.032). The GCC thickness of the temporal outer ring region in group B was significantly lower than that in group A at 6mo after surgery(P=0.038).CONCLUSION: Enlarging the extent of ILM peeling doesn’t affect the IMH closure rate and visual acuity recovery, but the greater the extent of peeling, the greater the damage to the inner retinal structures.展开更多
基金supported by the National Key R&D Program of China(2021YFA1300403)the Youth Innovation Promotion Association of CAS(2020081)+3 种基金the CAS Project for Young Scientists in Basic Research(YSBR-093)the National Natural Science Foundation of China(32222007)the Innovation Platform for Academicians of Hainan Province(2022YSCXTD0005)the Science&Technology Specific Project in Agricultural High-Tech Industrial Demonstration Area of the Yellow River Delta(2022SZX12).
文摘Diatoms rely on fucoxanthin chlorophyll a/c-binding proteins(FCPs)for light harvesting and energy quenching under marine environments.Here we report two cryo-electron microscopic structures of photosystem I(PSI)with either 13 or five fucoxanthin chlorophyll a/c-binding protein Is(FCPIs)at 2.78 and 3.20Åresolutions from Thalassiosira pseudonana grown under high light(HL)conditions.Among them,five FCPIs are stably associated with the PSI core,these include Lhcr3,RedCAP,Lhcq8,Lhcf10,and FCP3.The eight additional Lhcr-type FCPIs are loosely associated with the PSI core and detached under the present purification conditions.The pigments of this centric diatom showed a higher proportion of chlorophylls a,diadinoxanthins,and diatoxanthins;some of the chlorophyll as and diadinoxanthins occupy the locations of fucoxanthins found in the huge PSI-FCPI from another centric diatom Chaetoceros gracilis grown under low-light conditions.These additional chlorophyll as may form more energy transfer pathways and additional diadinoxanthins may form more energy dissipation sites relying on the diadinoxanthin-diatoxanthin cycle.These results reveal the assembly mechanism of FCPIs and corresponding light-adaptive strategies of T.pseudonana PSI-FCPI,as well as the convergent evolution of the diatom PSI-FCPI structures.
基金Supported by a grant from the Natural Science Foundation of Tianjin City (No.20JCZXJC00040)Tianjin Key Medical Discipline (No.Specialty) Construction Project (No.TJYXZDXK-037A)。
文摘AIM: To observe the effects of the different extents of internal limiting membrane(ILM) peeling on the surgical success and anatomical and functional outcomes of idiopathic macular hole(IMH).METHODS: In this retrospective cohort study, 36 patients were reviewed and divided into two groups according to the extent of ILM peeling: group A(18 patients), with the peeling area within one-half of the optic disc macular distance as the radius;group B(18 patients), with the peeling area larger than that of group A but did not exceed the optic disc macular distance as the radius. The main outcomes included the best corrected visual acuity(BCVA), light-adaptive electroretinography, macular hole(MH) closure rate, central macular thickness(CMT), retinal nerve fiber layer(RNFL) and ganglion cell complex(GCC) thickness [nine regions based on the Early Treatment of Diabetic Retinopathy Study(ETDRS) ring] before and 1, 3, and 6mo after surgery.RESULTS: The closure rate was 94.4%(17/18) both in groups A and B. The BCVA in both groups improved significantly compared with the preoperative values, but there was no difference between the two groups. The b-wave amplitude of the electroretinogram analysis was significantly improved in both groups compared to that of the preoperative period, with a greater increase in group A than in group B at 6mo(P=0.017). The CMT in both groups gradually decreased after surgery, and there was no difference between the two groups. The RNFL thickness of the temporal outer ring region in group B was significantly lower than that in group A at 3 and 6mo after surgery(P=0.010, 0.032). The GCC thickness of the temporal outer ring region in group B was significantly lower than that in group A at 6mo after surgery(P=0.038).CONCLUSION: Enlarging the extent of ILM peeling doesn’t affect the IMH closure rate and visual acuity recovery, but the greater the extent of peeling, the greater the damage to the inner retinal structures.
