Study Of Astaxanthin Biosynthesize At Single Cell Level By Femtosecond Laser Manipulation

Single-cell techniques have been used to describe the composition and activities of cells, have been a key element in revealing the relationship of environmental distribution and activities of microorganisms, and have been used to detail dynamics of reactions in cells. Single-cell methods have also been essential to understanding problems in bioengineering such as the screening of high-product strains. Femtosecond laser has attractive in single-cell research for high temporal resolution and high spatial resolution. Study of astaxanthin biosynthesize at single cell level was performed with Haematococcus pluvialis and Phaffia rhodozyma by femtosecond laser manipulation in this article.The trapping of living cells by femtosecond laser tweezers was been studied. Q-value of femtosecond laser tweezers was measured and the trapping capability of femtosecond laser and continuous wave was compared. The result proved that femtosecond laser could be used as optical tweezers as well as continuous laser. Additional, a primary attempt was made in using optical crystal fiber as optical tweezers.A system study of activity of cells in the trapping of femtosecond laser tweezers was performed by the analysis of the effect of laser power and exposure time on cell activity. The range of laser power and exposure time for safe trapping has been provided. The transfer of single cell from the suspension to plate has been achieved successfully on the base of the trapping by femtosecond laser.Femtosecond laser pulse has been used as the method of mutagenesis for the first time. The cells of Haematococcus pluvialis and Phaffia rhodozyma have been treated with femtosecond laser at single cell level. The results showed that the mutagenesis by femtosecond laser at single cell level succeed for Haematococcus pluvialis while failed for Phaffia rhodozyma. A primary attempt was carry out in detecting of astaxanthin content in single cell by microspectroscopic method.The preparation of protoplast of Haematococcus pluvialis and Phaffia rhodozyma has been accomplished through the selection of appropriate enzyme and the analysis of conditions.Femtosecond laser induced cell fusion was achieved for the first time. The fusion of Phaffia rhodozyma protoplast was performed with femtosecond laser manipulation system. The factor which may affect the result of femtosecond laser induce fusion was investigated and the possible mechanism was studied. A hypothetical model of cell fusion induced by femtosecond laser was presented on the base of experimental result.