Expression, Purification and Characterization of Arginase from Helicobacter pylori in Its Apo Form

Arginase, a manganese-dependent enzyme that widely distributed in almost all creatures, is a urea cycle enzyme that catalyzes the hydrolysis of L-arginine to generate L-ornithine and urea. Compared with the well-studied arginases from animals and yeast, only a few eubacterial arginases have been characterized, such as those from H. pylori and B. anthracis. However, these enzymes used for arginase activity assay were all expressed with LB medium, as low concentration of Mn2+ was detectable in the medium, protein obtained were partially Mn2+ bonded, which may affect the results of arginase activity assay. In the present study, H. pylori arginase (RocF) was expressed in a Mn2+ and Co2+ free minimal medium, the resulting protein was purified through affinity and gel filtration chromatography and the apo-form of RocF was confirmed by flame photometry analysis. Gel filtration indicates that the enzyme exists as monomer in solution, which was unique as compared with homologous enzymes. Arginase activity assay revealed that apo-RocF had an acidic pH optimum of 6.4 and exhibited metal preference of Co2+>Ni2+>Mn2+. We also confirmed that heat-activation and reducing regents have significant impact on arginase activity of RocF, and inhibits S-(2-boronoethyl)-L-Cysteine (BEC) and Nω-hydroxy-nor-Arginine (nor-NOHA) inhibit the activity of RocF in a dose-dependent manner

Constructing dataset of classified drainage areas based on surface water-supply patterns in High Mountain Asia

The High Mountain Asia (HMA) region, ranging from the Hindu Kush and Tien Shan in the west to the Himalaya in the south with an altitude between 2000 and 8844 m, holds the largest reservoir of glaciers and snow outside Earth Polar Regions. In the last decades, numerous glaciers and lake areas there have undergone tremendous changes with water redistribution. In order to increase understanding of the pattern of distribution of water resources, and their dynamic changes at the basin scale, a watershed classification based on the water replenishment patterns dataset was constructed. The input dataset are from the Randolph Glacier Inventory V.6.0 and the vector data of rivers and streams. Four datasets were thus obtained: Glacier-fed and Runoff-fed Drainage Area (GRDA), Glacier-fed and Runoff-free Drainage Area (GDA), Glacier-free and Runoff-fed Drainage Area (RDA), and the Glacier-free and Runoff-free Drainage Area (NGRDA), and the numbers of these four types of basins are 87, 107, 32, and 448 separately. The statistical results show GRDA has the largest surface area, accounting for 82.2% of the total basin area in HMA, mainly in the region of the basin with outflow rivers or streams. Dominated by small basins, the GDA area accounts for the smallest area, only 3.86% and the RDA accounts for 5.62%. For NGRDA, most are with small areas, accounting for 8.32%, and mainly distributes in the closed basin of the Qiangtang Plateau. This dataset provides a fundamental classified data source for research on water resources, climate, ecology, and environment in HMA. The published data are available at https://data.4tu.nl/download/uuid:d07d748f-d10b-4308-9626-199ef05cc9af/ and http://www.dx.doi.org/10.11922/sciencedb.923.</p

Determining the immunological characteristics of a novel human monoclonal antibody developed against staphylococcal enterotoxin B

Staphylococci are the main cause of nosocomial infections globally. The exotoxin staphylococcal enterotoxin B (SEB) produced by methicillin-resistant Staphylococcus aureus is a major cause of pathology after a staphylococcal infection. We previously isolated an anti-SEB human monoclonal antibody designated as M0313. Here we further characterize this antibody in vitro and in vivo. Immunoblotting analysis and ELISA results indicated that M0313 accurately recognized and bound to SEB. Its binding affinity to native SEB was measured at the low nM level. M0313 effectively inhibited SEB from inducing mouse splenic lymphocyte and human peripheral blood mononuclear cell proliferation and cytokine release in cell culture. M0313 also neutralized SEB toxicity in BALB/c female mice. Most importantly, M0313 promoted the survival of mice treated with SEB-expressing bacteria. In-vivo imaging revealed that M0313 treatment significantly reduced the replication of SEB-expressing bacteria in mice. The neutralization capacity of M0313 correlated with its ability to block SEB from binding to major histocompatibility complex II and T-cell receptor by binding to the SEB residues 85–102 and 90–92. Thus, the monoclonal antibody M0313 may be developed into a therapeutic agent

Constructing dataset of classified drainage areas based on surface water-supply patterns in High Mountain Asia

The High Mountain Asia (HMA) region, ranging from the Hindu Kush and Tien Shan in the west to the Himalaya in the south with an altitude between 2000 and 8844 m, holds the largest reservoir of glaciers and snow outside Earth Polar Regions. In the last decades, numerous glaciers and lake areas there have undergone tremendous changes with water redistribution. In order to increase understanding of the pattern of distribution of water resources, and their dynamic changes at the basin scale, a watershed classification based on the water replenishment patterns dataset was constructed. The input dataset are from the Randolph Glacier Inventory V.6.0 and the vector data of rivers and streams. Four datasets were thus obtained: Glacier-fed and Runoff-fed Drainage Area (GRDA), Glacier-fed and Runoff-free Drainage Area (GDA), Glacier-free and Runoff-fed Drainage Area (RDA), and the Glacier-free and Runoff-free Drainage Area (NGRDA), and the numbers of these four types of basins are 87, 107, 32, and 448 separately. The statistical results show GRDA has the largest surface area, accounting for 82.2% of the total basin area in HMA, mainly in the region of the basin with outflow rivers or streams. Dominated by small basins, the GDA area accounts for the smallest area, only 3.86% and the RDA accounts for 5.62%. For NGRDA, most are with small areas, accounting for 8.32%, and mainly distributes in the closed basin of the Qiangtang Plateau. This dataset provides a fundamental classified data source for research on water resources, climate, ecology, and environment in HMA. The published data are available at https://data.4tu.nl/download/uuid:d07d748f-d10b-4308-9626-199ef05cc9af/ and http://www.dx.doi.org/10.11922/sciencedb.923.Optical and Laser Remote Sensin

Respiratory mucosal vaccination of peptide-poloxamine-DNA nanoparticles provides complete protection against lethal SARS-CoV-2 challenge

International audienceThe ongoing SARS-CoV-2 pandemic represents a brutal reminder of the continual threat of mucosal infectious diseases. Mucosal immunity may provide robust protection at the predominant sites of SARS-CoV-2 infection. However, it remains unclear whether respiratory mucosal administration of DNA vaccines could confer protective immune responses against SARS-CoV-2 challenge due to insurmountable barriers posed by the airway. Here, we applied self-assembled peptide-poloxamine nanoparticles with mucus-penetrating properties for pulmonary inoculation of a COVID-19 DNA vaccine (pSpike/PP-sNp). The pSpike/PP-sNp not only displays superior gene transfection and favorable biocompatibility in the mouse airway, but also promotes a tripartite immunity consisting of systemic, cellular, and mucosal immune responses that are characterized by mucosal IgA secretion, high levels of neutralizing antibodies, and resident memory phenotype T-cell responses in the lungs of mice. Most importantly, immunization with pSpike/PP-sNp completely eliminates SARS-CoV-2 infection in both upper and lower respiratory tracts and enables 100% survival rate of mice following lethal SARS-CoV-2 challenge. Our findings indicate PP-sNp is a promising platform in mediating DNA vaccines to elicit all-around mucosal immunity against SARS-CoV-2