Steady-state and time-resolved fluo- rescence spectroscopies have been used to study the excited state properties of Chl a in different ag- gregation forms of light-harvesting complex II (LHC II) from an intertidal gr...Steady-state and time-resolved fluo- rescence spectroscopies have been used to study the excited state properties of Chl a in different ag- gregation forms of light-harvesting complex II (LHC II) from an intertidal green alga, Bryopsis corticulans, i.e. LHC II monomer, trimer and oligomer. When either Chl a or Chl b was selectively excited, the observed decrease in Chl a fluorescence in the oligomer is proved to be caused mainly by the fast fluorescence quenching among Chl a molecules, rather than by the decrease in Chl b-to-Chl a singlet excitation transfer efficiency. Analyses of the picosecond time-resolved fluorescence kinetics identified two exponential de- cay components in all of the three forms of LHC II: a longer-lived component (4.1―4.7 ns) originating from fluorescence emission of Chl a, and a shorter-lived one (135―540 ps) from the rapid equilibration of singlet excitation among Chl a molecules. The time constant of excitation equilibration is 135 ps in oli- gomer, 520 ps in trimer and 540 ps in monomer. These results imply that LHC II in oligomer form is inherently able to quench Chl a excitation, a mecha- nism which may be related to the photoprotection of PS II via changing the degree of LHC II aggregation in Bryopsis corticulans.展开更多
文摘目的探讨维持性血液透析患者(maintenance hemodialysis,MHD)蛋白质能量消耗(protein-energy wasting,PEW)与甲状旁腺激素(parathyroid hormone,PTH)水平的关系。方法采用横断面研究,选取2022年1月至2023年5月在安徽医科大学第三附属医院行维持性血液透析治疗的成年患者150例为研究对象,依据PTH水平将患者分为低PTH组(<150 ng/L)、PTH达标组(150~300 ng/L)、较高PTH组(>300~600 ng/L)及高PTH组(PTH>600 ng/L),PEW的诊断采用国际肾脏营养与代谢学会(international society of renal nutrition and metabolism,ISRNM)提出的PEW诊断标准,采用logistic回归分析探究PEW与PTH水平的关系。结果150例MHD患者中蛋白质能量消耗组52例(34.7%),低PTH组患者蛋白质能量消耗患病率高于PTH达标组、较高PTH组及高PTH组(χ^(2)=20.64,P<0.05),单因素logistic回归分析结果显示,低PTH(OR=13.810,95%CI:2.907~65.603,P=0.001)与PEW风险增加相关,低PTH组发生PEW的风险是高PTH组的13.810倍;多因素logistic回归分析结果显示,低PTH(OR=19.891,95%CI:1.810~218.620,P=0.014)、C反应蛋白(OR=1.056,95%CI:1.015~1.099,P=0.007)与PEW风险增加独立相关,血红蛋白(OR=0.959,95%CI:0.931~0.988,P=0.005)、上臂中部周径(OR=0.544,95%CI:0.338~0.875,P=0.012)与PEW风险降低独立相关,低PTH组发生PEW的风险是高PTH组的19.891倍;PTH达标组、较高PTH组与高PTH组相比,PEW发生风险差异均无统计学意义(均P>0.05)。结论低PTH的患者发生PEW的风险显著增加,临床工作中应重视对低PTH血症的防治,对降低PEW发生风险具有重要的意义。
基金This work was supported by the National Natural Science Foundation of China(Grant No.20273077)the Knowledge Innovation Program of Chinese Academy of Sciences(Grant No.KSCX2-SW-130).
文摘Steady-state and time-resolved fluo- rescence spectroscopies have been used to study the excited state properties of Chl a in different ag- gregation forms of light-harvesting complex II (LHC II) from an intertidal green alga, Bryopsis corticulans, i.e. LHC II monomer, trimer and oligomer. When either Chl a or Chl b was selectively excited, the observed decrease in Chl a fluorescence in the oligomer is proved to be caused mainly by the fast fluorescence quenching among Chl a molecules, rather than by the decrease in Chl b-to-Chl a singlet excitation transfer efficiency. Analyses of the picosecond time-resolved fluorescence kinetics identified two exponential de- cay components in all of the three forms of LHC II: a longer-lived component (4.1―4.7 ns) originating from fluorescence emission of Chl a, and a shorter-lived one (135―540 ps) from the rapid equilibration of singlet excitation among Chl a molecules. The time constant of excitation equilibration is 135 ps in oli- gomer, 520 ps in trimer and 540 ps in monomer. These results imply that LHC II in oligomer form is inherently able to quench Chl a excitation, a mecha- nism which may be related to the photoprotection of PS II via changing the degree of LHC II aggregation in Bryopsis corticulans.
