PSI-driven cyclic electron fl ow(CEF-I)helps higher plants avoid severe heat damage.Gelidium amansii,a red seaweed used in the production of agar,inhabits subtidal rocks but can be found in the intertidal zone.The bio...PSI-driven cyclic electron fl ow(CEF-I)helps higher plants avoid severe heat damage.Gelidium amansii,a red seaweed used in the production of agar,inhabits subtidal rocks but can be found in the intertidal zone.The biological role of CEF-I is still unclear in this organism.Wild G.amansii was exposed to 30℃heat stress for 12 h with continuous lighting.The results showed that treatment at 30℃gradually decreased maximal PSII photochemical effi ciency(F_(v)/F_(m)),linear electron transfer rate,and activity of photosynthetic reaction center.Both the maximal photochemical effi ciency under light(F_(v)'/F_(m)')and maximum quantum yield of light-adapted PSII(Φ_(PSII))were maintained at a relatively stable level during the initial 6 h and then signifi cantly decreased at 12 h.The up-regulated CEF-I helps to enhance proton gradient transfer across thylakoid membrane to protect oxygen-evolving complex against heat damage.Following the addition of a CEF-I inhibitor to plants,the F_(v)/F m greatly decreased,suggesting that the CEF-I alleviates degree of photoinhibition caused by strong light.The results of measurement of antioxidant enzymes,including superoxide dismutase(SOD),ascorbate peroxidase(APX)and catalase(CAT),and the contents of H_(2)O_(2)and malonaldehyde(MDA)provided additional evidence that CEF-I plays a protective role to a certain extent for G.amansii to manage stress at 30℃.Therefore,it can be concluded that CEF-I enables G.amansii to survive in intertidal zones by protecting it from the heat damage caused by high temperature stress.展开更多
Materials Wild algae was collected by divers from the Sanggou Bay, Rongcheng County. The mature fe-male gametophyte and tetrasporaphyte were selected as mother seaweed, washed with purified seawaterand prepared for sp...Materials Wild algae was collected by divers from the Sanggou Bay, Rongcheng County. The mature fe-male gametophyte and tetrasporaphyte were selected as mother seaweed, washed with purified seawaterand prepared for spore collection.展开更多
Gelidium amansii agar was fractionated on DEAE-cellulose and four fractions were obtained sequentially. The yields of 1.0 mol/L NaCl fraction and 2.5 mol/L NaCl fraction were 2.80% and 2.03%. They are highly sulfated ...Gelidium amansii agar was fractionated on DEAE-cellulose and four fractions were obtained sequentially. The yields of 1.0 mol/L NaCl fraction and 2.5 mol/L NaCl fraction were 2.80% and 2.03%. They are highly sulfated agar, and named as agaropectin with sulfate content being 22.8% and 32.5%, respectively. The anticoagulant experiment results show that agaropectin could effectively prolong the coagulation time in a dose-dependent manner in vitro. Agaropection could be absorbed and effectively prolong the plasma coagulation time in vivo. After intragastric administration at the doses of 100, 200, and 400 mg/kg·d in rats for 15 days, TT (thrombin time), CT (coagulation time), PT (prothrombin time), and APTT (activated partial thromboplastin time) could be effectively prolonged and the plasma Fib level could be significantly lowered.展开更多
The effect of sonication pretreatment condition on Eucheuma cottonii and Gelidium amansii seaweed towards agar extraction wae studied.Four parameters were changed during sonication to investigate the effects on agar y...The effect of sonication pretreatment condition on Eucheuma cottonii and Gelidium amansii seaweed towards agar extraction wae studied.Four parameters were changed during sonication to investigate the effects on agar yield and quality.These parameters include the time interval,concentration ratio,frequency,and intensity.The highest amount of agar extracted from Eucheuma cottonii species could be obtained from the time interval of 30min,seaweed weight to solvent volume ratio of 1:20,the frequency of 35Hz,and the sonication power intensity of 30%.For Gelidium amansii species,the best agar yield also could be obtained from the time interval of 30 min,1:20 of seaweed weight to water volume ratio,the frequency of 35Hz,and power intensity of 30%.From the experiment,sonication pretreatment signifi cantly influenced the yield and properties of extracted agar.The sonication with autoclaved seaweed produced agar containing less sulfate content,which is an excellent chemical property for gel electrophoresis applications.The gelstrength of sonication with autoclaving for both seaweeds,Eucheuma and Gelidium species was the highest among those by sonication with direct heating,which proved that sonication pretreatment with autoclaving could enhance the physical properties of the agar.展开更多
基金Supported by the National Key R&D Program of China(No.2019YFD0900700)。
文摘PSI-driven cyclic electron fl ow(CEF-I)helps higher plants avoid severe heat damage.Gelidium amansii,a red seaweed used in the production of agar,inhabits subtidal rocks but can be found in the intertidal zone.The biological role of CEF-I is still unclear in this organism.Wild G.amansii was exposed to 30℃heat stress for 12 h with continuous lighting.The results showed that treatment at 30℃gradually decreased maximal PSII photochemical effi ciency(F_(v)/F_(m)),linear electron transfer rate,and activity of photosynthetic reaction center.Both the maximal photochemical effi ciency under light(F_(v)'/F_(m)')and maximum quantum yield of light-adapted PSII(Φ_(PSII))were maintained at a relatively stable level during the initial 6 h and then signifi cantly decreased at 12 h.The up-regulated CEF-I helps to enhance proton gradient transfer across thylakoid membrane to protect oxygen-evolving complex against heat damage.Following the addition of a CEF-I inhibitor to plants,the F_(v)/F m greatly decreased,suggesting that the CEF-I alleviates degree of photoinhibition caused by strong light.The results of measurement of antioxidant enzymes,including superoxide dismutase(SOD),ascorbate peroxidase(APX)and catalase(CAT),and the contents of H_(2)O_(2)and malonaldehyde(MDA)provided additional evidence that CEF-I plays a protective role to a certain extent for G.amansii to manage stress at 30℃.Therefore,it can be concluded that CEF-I enables G.amansii to survive in intertidal zones by protecting it from the heat damage caused by high temperature stress.
文摘Materials Wild algae was collected by divers from the Sanggou Bay, Rongcheng County. The mature fe-male gametophyte and tetrasporaphyte were selected as mother seaweed, washed with purified seawaterand prepared for spore collection.
基金the Innovative Key Project of Chinese Academy of Sciences (KZCX2-YW-209)the Department of Science and Technology of Shandong Province (2007BS07004)
文摘Gelidium amansii agar was fractionated on DEAE-cellulose and four fractions were obtained sequentially. The yields of 1.0 mol/L NaCl fraction and 2.5 mol/L NaCl fraction were 2.80% and 2.03%. They are highly sulfated agar, and named as agaropectin with sulfate content being 22.8% and 32.5%, respectively. The anticoagulant experiment results show that agaropectin could effectively prolong the coagulation time in a dose-dependent manner in vitro. Agaropection could be absorbed and effectively prolong the plasma coagulation time in vivo. After intragastric administration at the doses of 100, 200, and 400 mg/kg·d in rats for 15 days, TT (thrombin time), CT (coagulation time), PT (prothrombin time), and APTT (activated partial thromboplastin time) could be effectively prolonged and the plasma Fib level could be significantly lowered.
基金Supported by the University of Malaya under Equitable Society Research Cluster(ESRC)(No.GC002A-15SBS)
文摘The effect of sonication pretreatment condition on Eucheuma cottonii and Gelidium amansii seaweed towards agar extraction wae studied.Four parameters were changed during sonication to investigate the effects on agar yield and quality.These parameters include the time interval,concentration ratio,frequency,and intensity.The highest amount of agar extracted from Eucheuma cottonii species could be obtained from the time interval of 30min,seaweed weight to solvent volume ratio of 1:20,the frequency of 35Hz,and the sonication power intensity of 30%.For Gelidium amansii species,the best agar yield also could be obtained from the time interval of 30 min,1:20 of seaweed weight to water volume ratio,the frequency of 35Hz,and power intensity of 30%.From the experiment,sonication pretreatment signifi cantly influenced the yield and properties of extracted agar.The sonication with autoclaved seaweed produced agar containing less sulfate content,which is an excellent chemical property for gel electrophoresis applications.The gelstrength of sonication with autoclaving for both seaweeds,Eucheuma and Gelidium species was the highest among those by sonication with direct heating,which proved that sonication pretreatment with autoclaving could enhance the physical properties of the agar.
