Plasmid DNA extraction by double magnetic beads method and its application / 生物工程学报

Plasmids are the most commonly used gene carriers in the field of gene synthesis and sequencing. However, the main problems faced by traditional plasmid DNA extraction technology are low extraction throughput and high production cost, so they cannot meet the growing demand. In this study, a double-magnetic-bead method (DMBM) for plasmid extraction was developed based on the principle of plasmid extraction. The effects of the input of magnetic beads, the size of plasmid DNA fragments, and the volume of bacterial on plasmid DNA extraction were explored. In addition, the quality, throughput, and cost of plasmid DNA extraction were also compared between this technique and the commercial plasmid DNA extraction kits. The results showed that the DMBM can meet the needs of extracting plasmid DNA with different cell densities and fragment lengths. Moreover, the sensitivity and quality of plasmid extraction by the DMBM method were both superior to those of the centrifugal adsorption column method. In addition, this technique could be applied on a 96-channel automated nucleic acid extractor, resulting in higher purity of the extracted plasmid DNA, 80% reduction in extraction time, and 57.1% reduction in cost. It also reduces manual operations, achieving high-throughput and low-cost plasmid DNA extraction, thus may facilitate gene synthesis and sequencing.

Correlative study between NT-proBNP,cTnI levels and inflammation reaction in patients with acute respiratory distress syndrome caused by severe pneumonia / 重庆医学

Objective To investigate the association betweent clinical markers of N‐terminal probrain natriuretie peptide (NT‐proBNP) ,cardiac troponin I (cTnI) and C‐reaction protein (CRP) in the patients with acute respiratory distress syndrome (ARDS) caused by severe pneumonia and to reveal the pathophysiologic process of myocardial injury after ARDS .Methods Totally 33 patients diagnosed as ARDS caused by severe pneumonia were divided into 3 groups:mild group ,moderate group and severe group according to the New Berlin definition of ARDS .Arterial blood gas analysis ,NT‐proBNP ,cTnI and CRP were observed be‐fore the treatment .Statistics were used for the analyses .Results The NT‐proBNP level in the severe group was significantly higher than that in the mild and moderate groups (P 0 .05) .The CRP level in the severe group was significantly higher than that in the mild (P<0 .05) .Moreover ,the NT‐proBNP level of 33 patients was positively associated with the both CRP and cTnI level (P<0 .05) .Conclusion The seriously inflammatory response mediates myocardial injury probably because of ARDS .Combined NT‐proBNP and cTnI testing is important for evaluating the condition of ARDS at the early stage .