BackgroundHuman-like H3N2 influenza viruses have repeatedly been transmitted to domestic pigs in different regions of the world, but it is still uncertain whether any of these variants could become established in pig populations. The fact that different subtypes of influenza viruses have been detected in pigs makes them an ideal candidate for the genesis of a possible reassortant virus with both human and avian origins. However, the determination of whether pigs can act as a “mixing vessel” for a possible future pandemic virus is still pending an answer. This prompted us to gather the epidemiological information and investigate the genetic evolution of swine influenza viruses in Jilin, China.MethodsNasopharyngeal swabs were collected from pigs with respiratory illness in Jilin province, China from July 2007 to October 2008. All samples were screened for influenza A viruses. Three H3N2 swine influenza virus isolates were analyzed genetically and phylogenetically.ResultsInfluenza surveillance of pigs in Jilin province, China revealed that H3N2 influenza viruses were regularly detected from domestic pigs during 2007 to 2008. Phylogenetic analysis revealed that two distinguishable groups of H3N2 influenza viruses were present in pigs: the wholly contemporary human-like H3N2 viruses (represented by the Moscow/10/99-like sublineage) and double-reassortant viruses containing genes from contemporary human H3N2 viruses and avian H5 viruses, both co-circulating in pig populations.ConclusionsThe present study reports for the first time the coexistence of wholly human-like H3N2 viruses and double-reassortant viruses that have emerged in pigs in Jilin, China. It provides updated information on the role of pigs in interspecies transmission and genetic reassortment of influenza viruses.
Veronicastrum axillare polysaccharides (VAP) were isolated by cellulase‐assisted digestion. The optimum conditions (2 % cellulase, 47 °C for 2.5 h, then, 95 °C for 2.5 h, pH 4.1, solid/liquid ratio 1 : 7.6) were identified by a combination of single factor optimization and response surface DOE (design of experiment) methods, and achieved a yield of 4.7 %. Treatment with 1 % TCA for 10 min, then, 2 % DEAE‐cellulose removed protein and colored impurities. Purified VAP retained most of the radical‐scavenging activities and GES‐1 cell protection capability in vitro, indicating VAP were the key active components of V. axillare. Some molecular features were identified by FT‐IR and NMR analyses. The molecular weight was estimated from DOSY NMR experiments to be around 21 kDa. There were 6.3 % uronic acid residues in the VAP. The constituent sugars after TFA hydrolysis were identified by HPLC to include glucose, arabinose, rhamnose, galactose, and xylose in a molar ratio of 405 : 259 : 82 : 42 : 1.
Despite an outstanding agent for control of Lepidoptera, the diamide insecticide cyclaniliprole (CYCP) is a suspected carcinogen. In the present study, an analytical method was developed for the determination of CYCP in six fruits and vegetables (apple, grape, peach, bell pepper, lettuce, and tomato) using ultrahigh-performance liquid chromatography coupled with tandem mass spectrometry. Sample preparation was carried out by the acetonitrile-salting-out extraction followed by simple and fast cleanup of disposable pipette extraction tip containing styrene divinyl benzene and/or graphitized carbon black. Satisfactory linearity (r > 0.99) was obtained in the calibration range of 0.001–1 µg mL−1. Matrix effects decreased from −9.9–−17.9% to −1.0–−7.6% after the cleanup. The recoveries of CYCP at three spike levels (0.01, 0.1, and 1 mg kg−1) from different matrices were between 75.7% and 111.5%, with the intra-day (n = 5) and inter-day (n = 15) relative standard deviations lower than 12.1%. The limit of quantification was 0.01 mg kg−1. The developed method provides a good reference for routine monitoring of CYCP in these fruits and vegetables.
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