Biomedical subjects

Baojian Li

Publications and source records attributed to Baojian Li.

3 recordsLinked to original sources

PubMed2006

A highly efficient polyethylene glycol-mediated transformation method for mushrooms.

A highly efficient transformation system mediated by polyethylene glycol was developed for the cultivated mushroom Pleurotus ostreatus. Eighty to 180 integrative and stable-resistant colonies appeared per mug of DNA per 10(7) viable protoplasts in a transformation experiment with the hygromycin B phosphotransferase gene (hph), which is about 40-1800 times higher than that previously reported in P. ostreatus. One hundred to 150 transformants emitting green fluorescence were observed per mug of DNA per 10(7) viable protoplasts in a transformation with the green fluorescent protein gene, but green fluorescence disappeared 30 h after transformation, suggesting that the green fluorescent protein gene was only transiently expressed in P. ostreatus. Plasmid pAN7-1 was also transferred into two important cultivated mushrooms, Ganoderma lucidum and Lentinus edodes, and 120-150 and 85-100 transformants per mug of DNA per 10(7) viable protoplasts were obtained, respectively, which is seven to 38 times and 24-28 times greater than previously reported. These data indicate that this new polyethylene glycol-mediated transformation procedure is highly efficient for mushrooms, and could be a useful tool in mushroom improvement by gene engineering.

Drug Resistance, Fungal↗

PubMed2004

Prophylactic and therapeutic effects of small interfering RNA targeting SARS-coronavirus.

OBJECTIVES: To identify and characterize the siRNA duplexes that are effective for inhibition of SARS-CoV infection and replication in the non-human primate cells. This in vitro study will serve as the foundation for development of novel anti-SARS therapeutics. METHODS: 48 siRNA sequences were designed for targeting regions throughout entire SARS-CoV genome RNA including open-reading frames for several key proteins. Chemically synthesized siRNA duplexes were transfected into foetal rhesus kidney (FRhK-4) cells prior to or after SARS-CoV infection. The inhibitory effects of the siRNAs were evaluated for reductions of intracellular viral genome copy number and viral titres in the cell culture medium measured by Q-RT-PCR and CPE-based titration, respectively. Four siRNA duplexes were found to achieve potent inhibition of SARS-CoV infection and replication. A prolonged prophylactic effect of siRNA duplexes with up to 90% inhibition that lasted for at least 72 h was observed. Combination of active siRNA duplexes targeting different regions of the viral genome resulted in therapeutic activity of up to 80% inhibition. CONCLUSION: Chemically synthesized siRNA duplexes targeting SARS-CoV genomic RNA are potent agents for inhibition of the viral infection and replication. The location effects of siRNAs were revealed at both genome sequence and open-reading frame levels. The rapid development of siRNA-based SARS-CoV inhibitors marked a novel approach for combating newly emergent infectious diseases.

Animals↗

PubMed2003

Efficient linking and transfer of multiple genes by a multigene assembly and transformation vector system.

Introduction and expression of multiple transgenes is frequently required for basic and applied studies. However, at present, multigene transformation is very difficult due to technical limitations of existing methods. Here, we describe a vector system for efficient multigene assembly and transformation. The system consists of a transformation-competent artificial chromosome (TAC)-based acceptor vector together with two donor vectors. By exploiting the CreloxP recombination system and homing endonucleases, multiple rounds of gene assembly cycling were carried out with alternate use of the donor vectors, and multiple genes were sequentially delivered into the TAC vector. With this system, we created constructs containing as many as 10 foreign DNA fragments. Multiple genes, including six resistant genes stacked in a construct, were transferred into rice genome by Agrobacterium-mediated transformation. This system extends the repertoire of molecular genetic studies and biotechnological endeavors by enabling simultaneous manipulation of multiple genes.

Agrobacterium tumefaciens↗