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61.
Jairo Gooskens Jessika C. Zevenhoven-Dobbe Eric C. Claas Aloys C. M. Kroes Clara C. Posthuma 《PloS one》2014,9(4)
The pandemic influenza A (H1N1) 2009 virus (pH1N1) contains novel gene segments of zoonotic origin that lack virulence and antiviral resistance markers. We aimed to evaluate the applicability and accuracy of mass spectrometry-based comparative sequence analysis (MSCSA) to detect genetic mutations associated with increased virulence or antiviral resistance in pH1N1. During the 2009 H1N1 pandemic, routine surveillance specimens and clinical antiviral resistance monitoring specimens were analyzed. Routine surveillance specimens obtained from 70 patients with pH1N1 infection were evaluated for mutations associated with increased virulence (PB1-F2, PB2 and NS1 genes) or antiviral resistance (neuraminidase gene, NA) using MSCSA and Sanger sequencing. MSCSA and Sanger sequencing results revealed a high concordance (nucleotides >99%, SNPs ∼94%). Virulence or resistance markers were not detected in routine surveillance specimens: all identified SNPs encoded for silent mutations or non-relevant amino acid substitutions. In a second study population, the presence of H275Y oseltamivir resistant virus was identified by real-time PCR in 19 of 35 clinical antiviral resistance monitoring specimens obtained from 4 immunocompromised patients with ≥14 days prolonged pH1N1 excretion. MSCSA detected H275Y in 24% (4/19) of positive specimens and Sanger sequencing in 89% (17/19). MSCSA only detected H275Y when the mutation was dominant in the analyzed specimens. In conclusion, MSCSA may be used as a rapid screening tool during molecular surveillance of pH1N1. The low sensitivity for the detection of H275Y mutation in mixed viral populations suggests that MSCSA is not suitable for antiviral resistance monitoring in the clinical setting. 相似文献
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Shaoliang Chen Jinke Li Tianhua Wang Shasheng Wang Andrea Polle Aloys Hüttermann 《Journal of Plant Growth Regulation》2003,21(3):224-233
We designed two experiments to investigate the osmotic stress and ion-specific effects on xylem abscisic acid (ABA) and the
relevance to salinity tolerance in one-year-old seedlings of Populus euphratica Oliv. (a salt-resistant genotype) and one-year-old
rooted cuttings of P. 'popularis 35-44' (P. popularis) (a salt-sensitive genotype). Net photosynthetic rates (Pn) and unit
transpiration rates (TRN) of the two genotypes were significantly decreased upon osmotic shock caused by PEG 6000 (osmotic
potential = -0.24 MPa) or iso-NaCl (50 mM). Shoot xylem ABA concentrations in both genotypes increased rapidly after the onset
of PEG stress, resulting from a decreased water flow. NaCl-treated trees of P. euphratica maintained considerably greater
concentrations of ABA than PEG-treated plants in a longer term, whereas salinized P. popularis exhibited a transient accumulation
of ABA in the shoot. TRN was greatly enhanced in both genotypes when pressure (0.24 MPa) was applied to counteract the osmotic
suction of 50 mM NaCl. Pressurizing of root systems diluted solutes in the root xylem, but the dilution effect was more pronounced
in P. popularis. Root xylem ABA concentrations in P. euphratica steadily increased with salt stress although pressurization
lowered its levels. In contrast, there were no observed changes in ABA response to salinity in pressured P. popularis. Therefore,
we concluded that the salt-tolerant P. euphratica had a greater capacity to synthesize ABA under saline conditions, which
may partially result from specific salt effects. In addition, P. euphratica exhibited a higher capacity for salt (Na+ and
Cl-) transport control under salt stress, compared with P. popularis. The possible association between ABA and salt transport
limitation, and the relevance to salinity tolerance were discussed. 相似文献
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