Characterization and immunogenicity of SARS-CoV-2 spike proteins with varied glycosylation.

The ongoing coronavirus disease-19 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has drastically changed our way of life and continues to have an unmitigated socioeconomic impact across the globe. Research into potential vaccine design and production is focused on the spike (S) protein of the virus, which is critical for virus entry into host cells. Yet, whether the degree of glycosylation in the S protein is associated with vaccine efficacy remains unclear. Here, we first optimized the expression of the S protein in mammalian cells. While we found no significant discrepancy in purity, homogeneity, or receptor binding ability among S proteins derived from 293F cells (referred to as 293F S-2P), 293S GnTI- cells (defective in N-acetylglucosaminyl transferase I enzyme; 293S S-2P), or TN-5B1-4 insect cells (Bac S-2P), there was significant variation in the glycosylation patterns and thermal stability of the proteins. Compared with the partially glycosylated 293S S-2P or Bac S-2P, the fully glycosylated 293F S-2P exhibited higher binding reactivity to convalescent sera. In addition, 293F S-2P induced higher IgG and neutralizing antibody titres than 293S or Bac S-2P in mice. Furthermore, a prime-boost-boost regimen, using a combined immunization of S-2P proteins with various degrees of glycosylation, elicited a more robust neutralizing antibody response than a single S-2P alone. Collectively, this study provides insight into ways to design a more effective SARS-CoV-2 immunogen.

Red mud based passivator reduced Cd accumulation in edible amaranth by influencing root organic matter metabolism and soil aggregate distribution.

Red mud was a highly alkaline hazardous waste, and their resource utilization was a research hotspot. In this study, influencing mechanisms of red mud based passivator on the transformation of Cd fraction in acidic Cd-polluted soil, photosynthetic property, and Cd accumulation in edible amaranth were investigated based on the evaluation of Cd adsorption capacity, root metabolic response, and soil aggregate distribution. Results showed that red mud exhibited good Cd adsorption capacities at about 35 °C and pH 9 in an aqueous solution, and the adsorption behavior of red mud on Cd in rhizosphere soil solution was considered to have some similarity. In the soil-pot trial, red mud application significantly facilitated edible amaranth growth by enhancing the maximum photochemical efficiency and light energy absorption by per unit leaf area by activating more reaction centers. The main mechanisms of rhizosphere soil Cd immobilisation by red mud application included: i) the reduction of mobilized Cd caused by the increasing negative surface charge of soil and precipitation of Cd hydroxides and carbonates at high pH; ii) the increase of organics-Cd complexes caused by the increasing -OH and -COOH amounts adsorbed on the surface of rhizosphere soil after red mud application; and iii) the decrease of available Cd content in soil aggregates caused by the increasing organic matters after red mud application. This study would provide the basis for the safe utilization of red mud remediating acidic Cd-polluted soil.

Serum Uric Acid Levels and Outcomes After Acute Ischemic Stroke.

Previous studies assessing the association between serum uric acid levels and neurological outcome after acute ischemic stroke reported conflicting results. A systematic review and meta-analysis were conducted to assess the impact of serum uric acid levels on outcome after acute ischemic stroke. Pubmed, Embase, Web of Science, and Google scholar were searched through September 26, 2014 to identify eligible published or unpublished studies on the association between serum uric acid levels and outcome after acute ischemic stroke. Hazard ratio (HR) for poor outcome or mean differences of serum uric acid levels with 95% confidence intervals (95% CIs) were pooled using meta-analysis. The primary outcome was occurrence of poor outcomes, while the secondary outcome was the mean differences of serum uric acid levels in patients with good or poor outcomes. Ten eligible studies with a total of 8131 acute ischemic stroke patients were included into the meta-analysis. Compared with low serum uric acid level, high serum uric acid level was associated better outcome after acute ischemic stroke (HR = 0.77, 95% CI 0.68-0.88, P = 0.0001). Sensitivity analysis further identified the prognostic role of serum uric acid levels on outcome after acute ischemic stroke. Patients with good outcomes had a higher serum uric acid level compared with those with poor outcome (mean difference = 30.61 µmol/L, 95% CI 20.13-41.08, P < 0.00001). There was no obvious risk of publication bias in the meta-analysis. This meta-analysis supports that serum uric acid level has a protective effect on neurological outcome after acute ischemic stroke. High uric acid level at the onset is a biomarker of better prognosis in patients with acute ischemic stroke.