Rapid improvement of lipase production in Penicillium expansum by genome shuffling / 生物工程学报

In the present study, the genome shuffling was used to improve lipase production of Penicillium expansum. A lipase producing mutant strain-Penicillium expansum FS8486 and a wild type of Aspergillus Tamarii FS-132 isolated from soil of a volcano in Xinjiang were used as the parental strains. After two rounds of genome shuffling, several elite daughter strains were screened. The lipase activity in one of the daughter strains was increased 317% over the starting strain FS8486. Comparisons of the morphology, RAPD (Random Amplification of Polymorphic DNA) polymorphism and the fatty acid compositions between the daughter and the parental strains suggested that the filial generation were generated by genome shuffling. In this study, the genome shuffling used successfully first time in eukaryotic microorganism and increases the production of the desired metabolite in short time, the study will be useful to spread the genome shuffling in eukaryotic microbial breeding.

Selection and inhibitory effect analysis of siRNAs specific to ORF2-4 of porcine reproductive and respiratory syndrome virus / 生物工程学报

RNA interference (RNAi) is a powerful tool in gene function research. In order to investigate the role of GP2, GP3 and GP4 of porcine reproductive and respiratory syndrome virus (PRRSV) in the viral replication, small interference RNAs (siRNAs) directed to ORF2, ORF3 and ORF4 were designed and 12 short hairpin RNA (shRNA) expression vectors were constructed (designed as 21,22,23,24,31,32,33,34,41,42,43 and 44). Cells treated with shRNA expression vectors were infected by PRRSV. The effective shRNA expression vectors were selected by fluorescent quantatitive PCR (FQ-PCR). The virus titer of supernatant of the cells treated with effective shRNA expression vectors (23,24,31,34 and 41) were reduced by 184 to 4.65 folds compared with that of controls.