Biochemical Composition And Transcriptome Analysis Of Euglena Slenderness Adapted To Various Environmental Factors

Euglena is a kind of unique unicellular algae with high adaptability.It can survive in an extreme environment,but the reason is unclear.This experiment was conducted by adding paromomycin(1ug/m L,5ug/m L,25ug/m L),sodium chloride(Na Cl)(1%),cadmium chloride(Cd Cl₂)(0.5m M,1m M,1.5m M),alcohol(0.5%?1%?1.5%)and glucose(0.5%?1%?1.5%)in culture medium respectively to analyze its effect on Euglena gracilis growth,biochemical components(paramylon,chlorophyll,carotenoid,and fatty acids)and the molecular level(transcription),and took a preliminary exploration into the possible adaptation mechanism of E.gracilis in the complex environment.The main contents and results of this thesis are as follows:(1)Glucose and alcohol promoted the growth of Euglena with glucose treatment being the most significant.,while Cd Cl₂,Na Cl and paromomycin inhibited the growth of E.gracilis.(2)Alcohol,glucose,Na Cl and Cd Cl₂ treatments all reduced the chlorophyll and carotenoids in E.gracilis cells significantly.However,paromomycin had no significant effect on these two groups of pigments.(3)Paramycin,Na Cl and Cd Cl₂ had no significant effect on the content of paramylon in E.graicilis cells.However,glucose or alcohol could significantly promote the synthesis of paramylon,and 0.5%(m/v)of glucose treatment was the most significant,which increased by 486.60%compared with the control.This was followed by 0.5%(v/v)alcohol treatment,which increased by 135.43%.(4)The fatty acid content of E.gracilis cells increased in all treatments.The effect of glucose on promoting fatty acid content was the most obvious,which increased by 66.81%?307.78%compared with the control group.Cd Cl₂ treatment had the lowest promotion effect,with an increase of only 18.96?31.42%.Except for paramycin,the proportion of myristic acid(C14:0),C11-C14 fatty acid and saturated fatty acid in the alcohol,glucose,Na Cl and Cd Cl₂ treatment was higher than that in the control.(5)A de novo high-throughput second-generation transcriptome sequencing analysis was carried out on E.gracilis treated under different conditions.The results showed that no core signature genes for various environmental changes were found as expected,and the effects of different treatments on transcriptome were also significantly different.The number of differentially expressed genes in Cd Cl₂treatment was the highest.Some genes related to metabolisms of amino acids,carbohydrates,and lipids,photosynthesis and respiration were described and analyzed in details,involving 67 enzymes.(6)The biochemical changes and transcriptome of E.gracilis under different treatments were analyzed in combination.We targeted some interesting differential expressed genes and enriched pathways according to various treatments.The differential composition and amounts of fatty acids in Na Cl and paromomycin treatments were analyzed.The effects of each treatment on chloroplasts and photosynthesis were also analysized.In summary,this theses focused on comparing the changes of biochemical components of E.gracilis under the treatments of paromomycin,sodium chloride,cadmium chloride,alcohol,and glucose,performed transcriptome analysis at the transcriptional level.The primary adaptation mechanism of E.gracilis to the complex environment has been initially explored,and it can also provide certain theoretical guidance for large-scale production of Euglenide bioactive substances.