The fast development of life science and technology such as organ transplantation,euthanasia,gene research plan and assisted reproductive technique and so forth brought happiness for human being,and at the same time they also brought lots of ethical dilemmas.System construction is an important approach to these problems and ethic guidance is absolutely necessary in this process.Moreover,the reasonable procedure is the important support for ethical guidance.Lastly,ethical problems are also closely related to scientists′ social responsibiliies of scientists.In conclusion,from the ultimate view,the advancement and balanced development of society is the fundamental factor to solve the negative effects of life science and technology.

In order to improve the yield of bacterial cellulose (BC), the fermentation medium of BC-producing strain J2 (Gluconobacter) was optimized, and BC ultra-micro-structure was observed. Initially, Plackett-Burman design was employed to evaluate eight variables which were relevant to BC production. Three statistically significant parameters including yeast extract, ZnSO4, ethanol were selected and other 5 variables were not significant (P > 0.05). The optimized levels of three variables were defined by Box-Behnken design and response surface methodology (RSM). BC ultra-micro-structure was observed by scanning electron microscope (SEM) with cotton cellulose as comparison. The results indicated that the BC yield under the optimum fermentation medium was 11.52 g/100 mL, which was as 1.35 times as that under the original fermentation medium. The SEM photos manifested that bacterial cellulose ribbon, with a diameter less than 0.1 microm, was less than cotton cellulose ribbon. The bacteria inside the cellulose net were eliminated after the NaOH treatment.
Cell Culture Techniques ; Cellulose ; biosynthesis ; ultrastructure ; Culture Media ; chemistry ; Fermentation ; Gluconobacter ; cytology ; metabolism