Highly Efficient Phosphate Sequestration in Aqueous Solutions Using Nanomagnesium Hydroxide Modified Polystyrene Materials

Phosphate removal is important for the control of eutrophication, and adsorption may serve as a powerful supplement to biological phosphate sequestration. Here, we develop a new composite adsorbent (denoted as HMO-PN) by encapsulating active nano-Mg­(OH)₂ onto macroporous polystyrene beads modified with fixed quaternary ammonium groups [CH₂N⁺(CH₂)₃Cl]. The N⁺-tailored groups can accelerate the diffusion of target phosphate through electrostatic attractions. The performance of the as-prepared HMO-PN was found to depend on the pH value of an aqueous medium. HMO-PN also exhibits high sorption selectivity toward the target phosphate. Kinetic equilibrium of phosphate adsorption can be achieved within 100 min, and the calculated maximum adsorption capacity is approximately 1.47 mmol/g (45.6 mg/g). Column experiments further show that the effluent concentration of phosphate can be reduced to below 0.5 mg/L (500 BV), suggesting highly efficient phosphate sequestration. Moreover, the exhausted HMO-PN can be readily regenerated using an alkaline brine solution

Additional file 1 of A potent synthetic nanobody with broad-spectrum activity neutralizes SARS-CoV-2 virus and the Omicron variant BA.1 through a unique binding mode

Additional file 1: Table S1. Epitope binning of spike nanobodies. Table S2. Cryo-EM data collection, refinement and validation statistics. Table S3. Conservation of epitopic residues in RBD for C5G2 binding from natural occurring SARS-Cov-2 variants

Optimizing Production of Antigens and Fabs in the Context of Generating Recombinant Antibodies to Human Proteins

<div><p>We developed and optimized a high-throughput project workflow to generate renewable recombinant antibodies to human proteins involved in epigenetic signalling. Three different strategies to produce phage display compatible protein antigens in bacterial systems were compared, and we found that <i>in vivo</i> biotinylation through the use of an Avi tag was the most productive method. Phage display selections were performed on 265 <i>in vivo</i> biotinylated antigen domains. High-affinity Fabs (<20nM) were obtained for 196. We constructed and optimized a new expression vector to produce <i>in vivo</i> biotinylated Fabs in <i>E</i>. <i>coli</i>. This increased average yields up to 10-fold, with an average yield of 4 mg/L. For 118 antigens, we identified Fabs that could immunoprecipitate their full-length endogenous targets from mammalian cell lysates. One Fab for each antigen was converted to a recombinant IgG and produced in mammalian cells, with an average yield of 15 mg/L. In summary, we have optimized each step of the pipeline to produce recombinant antibodies, significantly increasing both efficiency and yield, and also showed that these Fabs and IgGs can be generally useful for chromatin immunoprecipitation (ChIP) protocols.</p></div

Overview of targets and their success rates.

<p>Overview of the 265 antigen domains included in the study and what protein families they belong to. Family success rate was calculated as percentage of targets that were successful in selections and which also yielded at least one antibody that passed cell-based validation.</p><p>Overview of targets and their success rates.</p

Fab and IgG production.

<p>(A) Comparison of purification yields between different expression vectors using an anti-MBP Fab as an example. The large-scale purification method on the ÄKTA Xpress including a heat denaturation step was used. (B) SDS-PAGE gel showing the anti-MBP Fab produced with various expression vectors and purified in triplicate. (C) IgG production yields with and without the dilution strategy.</p

Comparison of antigen immobilization methods.

<p>(A) Three different affinity tags were tested for antigen immobilization in phage display; <i>in vivo</i> biotinylation through an Avi tag, SBP and GST tags. The diversity of Fabs derived from these differentially tagged antigens was then compared. (B) Immunoprecipitation with Fabs selected against either Avi-tagged antigen or GST-tagged antigen from a cell lysate expressing FLAG-tagged target protein. Immunoprecipitated antigen was detected with an M2 antibody against the FLAG tag. Fabs selected against Avi-tagged antigen generally show a higher recovery of the antigen.</p

Performance consistency among Fabs and IgGs generated against the same target.

<p>Multiple Fabs and IgGs against several targets were used to immunoprecipitate their corresponding FLAG-tagged antigens. Western blot was performed and the presence of the FLAG-tagged immunoprecipitated protein was detected with an antibody against the tag. A) CBX3. B) L3MBTl2, C) SFMBT2, D) TDRD3. FLAG-tagged GFP was used as control (data not shown). Fab batches are labeled with a trailer “-Bxxx” and IgG batches are labeled with a trailer “-IBxxx”. Fabs against CBX3 and SFMBT2 have been produced twice (CBX3 (B002, B004); SFMBT2 (B002, B004)) while Fabs against L3MBTL2 and TDRD3 have been produced only once (L3MBTL2 (B001); TDRD3 (B001)). Multiple IgGs have been produced with corresponding IB numbers. Fabs/IgGs derived from the same phagemid clone have similar efficiencies and show a high lot-to-lot consistency.</p