Biochar composites: Emerging trends, field successes, and sustainability implications

Engineered biochars are promising candidates in a wide range of environmental applications, including soil fertility improvement, contaminant immobilization, wastewater treatment and in situ carbon sequestration. This review provides a systematic classification of these novel biochar composites and identifies the promising future trends in composite research and application. It is proposed that metals, minerals, layered double hydroxides, carbonaceous nanomaterials and microorganisms enhance the performances of biochars via distinct mechanisms. In this review, four novel trends are identified and assessed critically. Firstly, facile synthesis methods, in particular ball milling and co-pyrolysis, have emerged as popular composite fabrication strategies that are suitable for large-scale applications. Secondly, biochar modification with green materials, such as natural clay minerals and microorganisms, align well with the on-going green and sustainable remediation (GSR) movement. Furthermore, new applications in soil health improvement and climate change mitigation support the realization of United Nation's Sustainable Development Goals (SDGs). Finally, the importance of field studies is getting more attention, since evidence of field success is critically needed before large-scale applications

Structural basis of broad HIV neutralization by a vaccine-induced cow antibody

Structure and mutagenesis studies show that a potent vaccine-elicited cow bnAb binds with a compact footprint to HIV gp120 CD4bs.</jats:p

Ku86 preserves chromatin integrity in cells adapted to high NaCl

Cells adapted to high NaCl have many DNA breaks both in cell culture and in the renal inner medulla in vivo; yet they survive, function, and even proliferate. Here, we show that Ku86 is important for maintaining chromosomal integrity despite the continued presence of DNA breaks. The Ku heterodimer is part of DNA-dependent PK (DNA-PK), a complex that contributes by nonhomologous end joining to repair of double-strand breaks. We demonstrate that cells deficient in Ku86, but not cells deficient in DNA-PKcs (the catalytic subunit of DNA-PK), are hypersensitive to high NaCl as manifested by profound inhibition of proliferation, aberrant mitosis, and increased chromosomal fragmentation. Lower eukaryotes, including the soil nematode Caenorhabditis elegans, lack a DNA-PKcs homologue but are able to adapt to high NaCl. We show that cells of C. elegans adapted to high NaCl have many DNA breaks, similar to the mammalian cells adapted to high NaCl. Ku86 mutant C. elegans as well as C. elegans fed with cku86 dsRNA also display hypersensitivity to high NaCl, characterized by a reduced number of progeny and prolonged generation time in high NaCl. We propose that Ku86 ameliorates the effects of high NaCl-induced DNA breaks in adapted cells by supporting alignment of the broken ends of the DNA and thus maintaining integrity of the fragmented chromatin

A Genetically Encoded aza-Michael Acceptor for Covalent Cross-Linking of Protein–Receptor Complexes

Selective covalent bond formation at a protein–protein interface potentially can be achieved by genetically introducing into a protein an appropriately “tuned” electrophilic unnatural amino acid that reacts with a native nucleophilic residue in its cognate receptor upon complex formation. We have evolved orthogonal aminoacyl-tRNA synthetase/tRNA_CUA pairs that genetically encode three aza-Michael acceptor amino acids, <i>N</i>^ε-acryloyl-(<i>S</i>)-lysine (AcrK, <b>1</b>), <i>p</i>-acrylamido-(<i>S</i>)-phenylalanine (AcrF, <b>2</b>), and <i>p</i>-vinylsulfonamido-(<i>S</i>)-phenylalanine (VSF, <b>3</b>), in response to the amber stop codon in Escherichia coli. Using an αErbB2 Fab-ErbB2 antibody-receptor pair as an example, we demonstrate covalent bond formation between an αErbB2-VSF mutant and a specific surface lysine ε-amino group of ErbB2, leading to near quantitative cross-linking to either purified ErbB2 <i>in vitro</i> or to native cellular ErbB2 at physiological pH. This efficient biocompatible reaction may be useful for creating novel cell biological probes, diagnostics, or therapeutics that selectively and irreversibly bind a target protein <i>in vitro</i> or in living cells

A Structurally Distinct Human Mycoplasma Protein that Generically Blocks Antigen-Antibody Union

Easy M Our immune systems can produce a vastly diverse repertoire of antibody molecules that each recognize and bind to a specific foreign antigen via a hypervariable region. However, there are a few bacterial antigens—such as Protein A, Protein G, and Protein L—that instead bind to the antibody's conserved regions and can bind to a large number of different antibodies. These high-affinity broad-spectrum antibody-binding properties have been widely exploited both in the laboratory and in industry for purifying, immobilizing, and detecting antibodies. Grover et al. (p. 656 ) have now identified Protein M found on the surface of human mycoplasma, which displays even broader antibody-binding specificity. The crystal structure of Protein M revealed how Protein-M binding blocks the antibody's antigen binding site. This mechanism may be exploited by mycoplasma to escape the humoral immune response. </jats:p

Mechanistic studies of the immunochemical termination of self-tolerance with unnatural amino acids

For more than 2 centuries active immunotherapy has been at the forefront of efforts to prevent infectious disease [Waldmann TA (2003) Nat Med 9:269–277]. However, the decreased ability of the immune system to mount a robust immune response to self-antigens has made it more difficult to generate therapeutic vaccines against cancer or chronic degenerative diseases. Recently, we showed that the site-specific incorporation of an immunogenic unnatural amino acid into an autologous protein offers a simple and effective approach to overcome self-tolerance. Here, we characterize the nature and durability of the polyclonal IgG antibody response and begin to establish the generality of p-nitrophenylalanine (pNO2Phe)-induced loss of self-tolerance. Mutation of several surface residues of murine tumor necrosis factor-α (mTNF-α) independently to pNO2Phe leads to a T cell-dependent polyclonal and sustainable anti-mTNF-α IgG autoantibody response that lasts for at least 40 weeks. The antibodies bind multiple epitopes on mTNF-α and protect mice from severe endotoxemia induced by lipopolysaccharide (LPS) challenge. Immunization of mice with a pNO2Phe43 mutant of murine retinol-binding protein (RBP4) also elicited a high titer IgG antibody response, which was cross-reactive with wild-type mRBP4. These findings suggest that this may be a relatively general approach to generate effective immunotherapeutics against cancer-associated or other weakly immunogenic antigens

Immunochemical termination of self-tolerance

The ability to selectively induce a strong immune response against self-proteins, or increase the immunogenicity of specific epitopes in foreign antigens, would have a significant impact on the production of vaccines for cancer, protein-misfolding diseases, and infectious diseases. Here, we show that site-specific incorporation of an immunogenic unnatural amino acid into a protein of interest produces high-titer antibodies that cross-react with WT protein. Specifically, mutation of a single tyrosine residue (Tyr86) of murine tumor necrosis factor-α (mTNF-α) to p-nitrophenylalanine (pNO2Phe) induced a high-titer antibody response in mice, whereas no significant antibody response was observed for a Tyr86 → Phe mutant. The antibodies generated against the pNO2Phe are highly cross-reactive with native mTNF-α and protect mice against lipopolysaccharide (LPS)-induced death. This approach may provide a general method for inducing an antibody response to specific epitopes of self- and foreign antigens that lead to a neutralizing immune response