Mutation of D201G near the receptor binding site significantly drives antigenic drift of circulating H9N2 subtype avian influenza virus.

The H9N2 subtype of avian influenza virus (H9N2 AIV) has caused significant losses in chicken flocks throughout China. Our previous research has shown that field isolates of H9N2 underwent antigenic drift to evolve into distinct groups with significant antigenic divergence from the commercially available vaccines. The present study sought to identify which single mutations that have naturally appeared in isolates from the past 5 years have driven antigenic drift. Six high-frequency mutation sites in/near the receptor binding site region were screened by comparing amino acid alignments of the H9N2 AIVs isolated from China between 2014 and 2019. Two substitutions (A168N and D201G) were demonstrated to have a significant impact on the antigenicity but did not change the growth kinetics of the virus. It is worth noting that the D201G substitution not only significantly changed the antigenicity but also caused immune escape against the parental virus. In conclusion, A168N and D201G substitution are newly discovered determinants that can significantly change the antigenicity of H9N2 AIV, which should be tracked during outbreaks.

Association of Serum Glucocorticoids with Various Blood Pressure Indices in Patients with Dysglycemia and Hypertension: the Henan Rural Cohort Study.

OBJECTIVE: To our knowledge, no definitive conclusion has been reached regarding the relationship between glucocorticoids and hypertension. Here, we aimed to explore the characteristics of glucocorticoids in participants with dysglycemia and hypertension, and to analyze their association with blood pressure indicators. METHODS: The participants of this study were from the Henan Rural Cohort study. A total of 1,688 patients 18-79 years of age were included in the matched case control study after application of the inclusion and exclusion criteria. Statistical methods were used to analyze the association between glucocorticoids and various indices of blood pressure, through approaches such as logistic regression analysis, trend tests, linear regression, and restricted cubic regression. RESULTS: The study population consisted of 552 patients with dysglycemia and hypertension (32.7%). The patients with co-morbidities had higher levels of serum cortisol ( P = 0.009) and deoxycortisol ( P < 0.001). The adjusted odds ratios (and 95% confidence intervals) for dysglycemia with hypertension were 1.55 (1.18, 2.04) for the highest tertile of Ln-cortisol compared with the lowest tertile. Additionally, the highest Ln-deoxycortisol levels were associated with increased prevalence of dysglycemia with hypertension by 159% (95% confidence interval: 122%, 207%). CONCLUSIONS: Serum deoxycortisol was positively correlated with systolic blood pressure, pulse pressure, mean arterial pressure, mean blood pressure, and mean proportional arterial pressure. Glucocorticoids (deoxycortisol and cortisol) increase the risk of hypertension in people with dysglycemia, particularly in those with T2DM.

A novel fluorescent nanoprobe that based on poly(thymine) single strand DNA-templated copper nanocluster for the detection of hydrogen peroxide.

In this paper, a label-free fluorescence nanoprobe is constructed based on poly(thymine) single strand DNA-templated Copper nanocluster (denote as: T-CuNCs) for the detection of hydrogen peroxide. In the assay, the fluorescent T-CuNCs will generate though the reaction of Cu2+, poly(thymine) and sodium ascorbate. However, the hydroxyl radical (.OH) will generated in the presence of H2O2, which is able to induced the oxidative lesions of poly(thymine) single chain DNA and lead to the poly(thymine) being splitted into shorter or single oligonucleotide fragments and lose the ability to template the fluorescent T-CuNCs again. Therefore, H2O2 can be detected by monitoring the fluorescence strength change of T-CuNCs. The experimental results show that the fluorescence intensity change of T-CuNCs has fantastic linearity versus H2O2 concentration in the range of 1-30 µM (R2 = 0.9947) and 30-80 µM (R2 = 0.9972) with the limit of detection (LOD) as low as 0.5 µM (S/N = 3). More important, the fluorescent nanoprobe was also successfully utilized on the detection of H2O2 in serum samples. Therefore, a label-free, costless and effective fluorescence method has been established for the detection of H2O2, the intrinsic properties of the nanoprobe endow its more potential applications in chemical and biological study.

Magnetic immunoassay using CdSe/ZnS quantum dots as fluorescent probes to detect the level of DNA methyltransferase 1 in human serum sample.

BACKGROUND: DNA methyltransferase 1 (DNMT1), a dominant enzyme responsible for the transfer of a methyl group from the universal methyl donor to the 5-position of cytosine residues in DNA, is essential for mammalian development and closely related to cancer and a variety of age-related chronic diseases. DNMT1 has become a useful biomarker in early disease diagnosis and a potential therapeutic target in cancer therapy and drug development. However, till now, most of the studies on DNA methyltransferase (MTase) detection have focused on the prokaryote MTase and its activity. METHODS: A magnetic fluorescence-linked immunosorbent assay (FLISA) using CdSe/ZnS quantum dots as fluorescent probes was proposed for the rapid and sensitive detection of the DNMT1 level in this study. Key factors that affect the precision and accuracy of the determination of DNMT1 were optimized. RESULTS: Under the optimal conditions, the limit of detection was 0.1 ng/mL, the linear range was 0.1-1,500 ng/mL, the recovery was 91.67%-106.50%, and the relative standard deviations of intra- and inter-assays were respectively 5.45%-11.29% and 7.03%-11.25%. The cross-reactivity rates with DNA methyltransferases 3a and 3b were only 4.0% and 9.4%, respectively. Furthermore, FLISA was successfully used to detect the levels of DNMT1 in human serum samples, and compared with commercial enzyme-linked immunosorbent assay (ELISA) kits. The results revealed that there was a good correlation between FLISA and commercial ELISA kits (correlation coefficient r=0.866, p=0.001). The linear scope of FLISA was broader than ELISA, and the measurement time was much shorter than ELISA kits. CONCLUSION: These indicated that the proposed FLISA method was sensitive and high throughput and can quickly screen the level of DNMT1 in serum samples.