Abstract An efficient and concise synthesis of cytotoxic 5,6-dihydro-α-pyrone (+)-brevipolide H has been accomplished in 12 long linear steps in 8.65% overall yield from readily available chiral synthons, d-galactal and ethyl l-lactate. The features of this synthesis are highly diastereoselective Simmons–Smith cyclopropanation and carbohydrate-based chiron approach to rapid access to key 5,6-dihydro-α-pyrone skeleton.
Dissolved organic matter (DOM) has been used frequently to distinguish different environmental samples based on its abundant fingerprint information. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) is the most powerful technique to analyze the complex composition of DOM. Balancing between the reproducibility of peak magnitude and peak diversity is a key factor for achieving reliable and reproducible fingerprint information of DOM with FT-ICR-MS. In this paper, a novel magnitude filter (MGF) method and a novel MS-MGF strategy were proposed to improve the data reproducibility of FT-ICR-MS analysis. With the MS-MGF strategy, a 20% magnitude filter threshold (TMGF) was recommended to remove magnitude outliers, and a relatively low signal-to-noise ratio (SNR) threshold of 3.5 was recommended to retain those low but stable-magnitude peaks. The total relative magnitude was recommended since it could obtain better reproducibility of MS analysis compared to other types of peak magnitude. In addition, three replicates were enough to obtain satisfactory reproducibility. More importantly, the proposed MS-MGF strategy was also adaptable to different FT-ICR-MS instruments and different experimental conditions. Overall, the results are expected to initiate the promising applications of the MS-MGF strategy to distinguish the reliable fingerprint characteristics of DOM samples from different sources.
Objective To transfect the respiratory syncytial virus(RSV)M 2-1 gene to the human lung adenocarcinoma PAa cell lines and obtain its expresstion. Methods The RSV M 2-1 gene was inserted into the plasmid(pJX-41) multiclone sites and transfected the PAa cell lines. The identification of the RSV M 2-1 gene expression was performed by RT-PCR, immunofluorescence and Western blot. Results ①The positive recombinants were digested by EcoRI and XhoI,the digested bands were 620 bp; ②the M 2-1 gene was amplified by RT-PCR, the amplified bands were 620 bp; ③The special green fluorescences were identified by immunofluorescence in cytochylema of the PAa cell transfected with M 2-1 gene; ④The special band of M 2-1 protein was identified by Western blot. Conclusion The RSV M 2-1 gene is successfully transfected and expressed in human pulmonary adenocarcinoma PAa cell lines, and it might be helpful to futher study.
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