英文文献报告

1、Reading Report,The effect of mixotrophy on microalgal growth, lipid content, and expression levels of the pathway genes in Chlorella sorokiniana,IF=3.425,主要内容,本文围绕生物能源微藻的培养进行研究。对目的微藻进行培养优化，对微藻的光合自养、异养和混合培养对其生长、脂质影响进行比较和分析，认为混合培养即可以大量促进微藻的生物量的累积并提高微藻的脂含量，而且代价较异养要低，可以作为微藻大规模培养的可选择手段。且C. sorokiniana CC

2、TCC M209220要优于另外两种微藻。 本文通过实时PCR，对（accD、acc1、rcbL）基因在C. sorokiniana CCTCC M209220中的表达量进行测试，并将表达差异和脂质含量进行比较，选出了和脂质含量密切相关的基因作为将来基因改造的候选基因。认为在非异养条件下，accD基因的表达水平可作为评估脂质含量的检验手段之一。,Contents,Introduction,The search of an improved raw material is one of the major objectives in biodiesel research. Microalgae

3、have many advantages for the production of biodiesel compared to other oil crops.,Introduction,Introduction,Mixotrophic Mixotrophic cultivation can complement photoautotrophy with organic material, thus shortening the growth cycle, increasing biomass yield, and decreasing the cost of heterotrophic m

4、icroalgae cultivation.,Introduction,Acetyl-CoA carboxylase (ACCase) In the branch point, acetyl-CoA carboxylase (ACCase) can catalyze acetyl-CoA to be converted to malonyl-CoA and to enter the pathway of lipid biosynthesis. This reaction is a critical step in fatty acid biosynthesis, so ACCase is co

5、nsidered a key enzyme for lipid accumulation.,Introduction,Introduction,Introduction,This paper analyzed the expression of three different genes (accD, acc1, and rbcL) in this strain under different mixotrophic conditions by real-time PCR. In order to study gene regulation related to lipid synthesis

6、, and examined the relative expression of three genes with respect to growth and oil accumulation, which offers useful insights into subsequent steps to improve this particular microalgal strain.,Results,Fig.1(a) Growth curves of N. oculata CCMP 525 under mixotrophic conditions,Effect of mixotrophic

7、 conditions on microalgal growth,Results,Fig.1(b) Growth curves of D. salina FACHB 435under mixotrophic conditions,Fig.1(c) Growth curves of C. sorokiniana CCTCC M209220 under mixotrophic conditions,Results,Results,Fig2(a): Lipid content of N. oculata CCMP 525, D.salina FACHB 435, and C. sorokiniana

8、 CCTCC M209220 under mixotrophic conditions,Effects of mixotrophic growth on protein and lipid content of algal biomass,Results,Fig2(b): Protein content of N. oculata CCMP 525, D.salina FACHB 435, and C. sorokiniana CCTCC M209220 under mixotrophic conditions,Results,Results,Fig.3(a) The glucose rema

9、ins of N.oculata CCMP 525 in the mixotrophic medium,Results,Fig 3.(b) The glucose remains of D. salina FACHB 435 in the mixotrophic medium,Results,Fig 3.(c) The glucose remains of C. sorokiniana CCTCC M209220 in the mixotrophic medium,Effects of mixotrophic conditions on oil contentand differential

10、gene expression in C. sorokiniana,Results,Results,Fig.4 Quantification of the expression of pathway genes, accD, related with lipid synthesis in C. sorokiniana CCTCC M209220 with different glucose concentrations,Results,Fig.4 Quantification of the expression of pathway genes, acc1, related with lipi

11、d synthesis in C. sorokiniana CCTCC M209220 with different glucose concentrations,Results,Fig.4 Quantification of the expression of pathway genes, rbcL, related with lipid synthesis in C. sorokiniana CCTCC M209220 with different glucose concentrations,Results,Fig. 5 Lipid content of C. sorokiniana C

12、CTCC M209220 during different population growth periods under mixotrophic conditions,Discussion,High lipid productivity is a key characteristic of an algal species for biodiesel production. In this study, C. sorokiniana CCTCC M209220 has exhibited a rapid growth rate and high oil content when cultur

13、ed in mixotrophic condition and thus can be considered as a promising candidate species that may in the future be genetically manipulated to improve oilyield further.,Discussion,Mixotrophic cultivation is an effective method to obtain high microalgal biomass productivity; furthermore, mixotrophy can

14、 beneficially affect the protein and lipid content of this biomass at least for species such as C. sorokiniana. A rend of increased lipid and protein content was observed perhaps because glucose provides additional energy and material for biosynthesis.,Discussion,Heteromeric ACCase(accD) is one of the key enzymes required for the synthesis of fatty acids. In this study, expression levels of the gene showed little correlation with lipid content as expression levels of acc1 were consistently low in each culture. Thus, the rbcL gene