Screening Of Microalgae With Anti-stress Activity And Role Of Spirulina In Healthy Ageing

With the development of the society and the increasing population,the demand of people for resources is growing,and the depletion of land resources is accelerating.Microalgae is attracting more attention as a sustainable renewable energy source.The use of microalgae is widespread,such as are biological carbon fixation,biofuels,wastewater treatment,and pharmaceuticals,etc.Microalgae contains many bioactivity ingredients with medicinal properties,so in order to provide abundant materials for the medical field,it is of great significance to develop microalgae.As aging of the population intensifies,aging and aging-related diseases bring increasing presseure of society.It is currently the hotspot of research about how to promote healthy.At present,health aging is focused on resistance to external stress,effective prolongation of lifespan,aging-related degenerative diseases,etc.Microalgae is an important biological resource,but currently,there are few studies on anti-aging about microalgae.This experiment uses the advantage of Caenorhabditis elegans in the activity screening for the microalgae ethanol extract.This experiment for the first time to detect the stress resistance of microalgae ethanol extract(MEE)and microalgae aqueous extract(MAE)by the advantages of Caenorhabditis elegans(C.elegans)in activity screening,20 strains of microalgae were screened out for the potential delay-aging activity,and they are distributed in 10 genus.Among them Chlorella,Chlamydomonas,Spirulina and Planktothrix are prominent.The most common Spirulina is the Spirulina platensis,so in this paper,Spirulina platensis was selected to evaluate the activity on delay-aging.Because the Spirulina platensis containes high protein,and many studies have shown that Spirulina platensis protein has a variety of bioactivities,so in this paper,the Spirulina platensis protein(SPP)and Spirulina platensis protein hydrolysate(SPPH)are the main research objects,and there are three aspect about the healthy aging research : the resistance of stress,lifespan related indicators and neurodegenerative diseases.The results showed that paraquatinduced worms fed with 2 mg/mL SPP and SPPH had the highest survival rate.Compared with the control,the worms treatwith SPP and SPPH was increased by 23.94% and 30.39%.Respectively,the average survival rate and sample were concentration dependence.Then we found SPP and SPPH can improve the tolerance of heat stress and increased the expression of heat shock protein HSP-16.2 on transgenic nematode CL2070 by 49.50% and 168.83%.Through the lifespan related assay,we found the SPP and SPPH can prolong lifespan in C.elegans by 7.02% and 10.44% compared with the control group,the results also show that SPP and SPPH can decrease the accumulation of lipofuscin in C.elegans by 12.63% and 28.39%,and they had no effect on the locomotor activity,growth,and reproduction capacity of C.elegans.Finally,we found SPP and SPPH had no effect on acetylcholinesterase(AchE)activity.Then the neuroprotective activities of SPP and SPP were studied through three neurodegenerative disease models AM141,CL2355 and NL5901.We find that SPP has no effect on aggregation of polyglutamine(polyQ)and amyloid-β(Aβ),but can inhibit the aggregation of α-synuclein by 11.37% compared with the control group;SPPH had no effect on the aggregation of the youth AM141,but can decreased the aggregation of AM141 during the adult period.And SPPH can also inhibit the toxictcity from Aβ,enhanced the chemotaxis index of CL2355 by 38.80%,decreased the aggregation of α-synuclein by 16.05% compared with the control group.In this dissertation,20 species were screened out for the potential delay-aging activity,which laid a foundation for the development of new microalgae.Then the anti-aging activity of SPP and SPPH were evaluated comprehensively,it was found that SPP and SPPH can improve the healthy aging,and may have intervention in neurodegenerative disease.