Nickel-Catalyzed Deaminative Allenylation of Amino Acid Derivatives: Catalytic Activity Enhanced by an Amide-Type NN₂ Pincer Ligand

Herein, we report a general and practical nickel-catalyzed deaminative allenylation of amino acid derivatives with terminal alkynes. The well-designed, electron deficient, and sterically hindered amide-type NN2 pincer ligand was crucial to the success of this transformation, enabling the coupling to occur under mild conditions with high efficiency. The remarkable features of this chemistry are its good scalability, its broad substrate scope, functional group tolerance, and the efficient modification of peptides, drugs, and natural products

Nickel-Catalyzed Deaminative Alkyl–Alkyl Cross-Coupling of Katritzky Salts with Cyclopropanols: Merging C–N and C–C Bond Activation

Herein, we report a general and practical nickel-catalyzed deaminative alkylation of Katritzky salts with cyclopropyl alcohols via merging C–N and C–C bond activation. This protocol enables the formation of an alkyl–alkyl bond along with the generation of a versatile ketone functional group in a single operation, thus providing a convenient approach for accessing β-alkyl ketones. This reaction is distinguished by its high functional group tolerance, broad substrate scope, and efficient late-stage derivatization of complex bioactive molecules

Nickel-Catalyzed Reductive Iminoarylation of Oxime Ester-Tethered Alkenes: Rapid Entrance to Diverse Functionalized Pyrrolines

Herein, we disclose a general and practical iminoarylation of alkenes by nickel-catalyzed reductive cross-coupling of unsaturated oxime esters with readily available aryl halides, providing an expedient approach for constructing pyrroline derivatives. The absence of organometallic reagents enables the reaction to occur under mild conditions with a broad substrate scope and good functional group tolerance. Moreover, other C-based electrophiles, including alkenyl, alkynyl and alkyl halides, or pseudohalides, were also competent substrates for this reaction

Tea Tree Oil Nanoemulsion Potentiates Antibiotics against Multidrug-Resistant Escherichia coli

Extensive efforts are underway to overcome the rising prevalence of antibiotic resistance. Combination therapy may be a potential method to treat multidrug-resistant (MDR) bacterial infections. In this study, tea tree essential oil (TTO) nanoemulsion (nanoTTO) was used in combination with antibiotics to kill microbes. Results showed that nanoTTO enhanced the activities of multiple antibiotics against MDR Escherichia coli (E. coli), and its antimicrobial activity was not changed against bacteria that were cultured in the presence of nanoTTO for 30 passages. Further studies to visualize and quantify intracellular antibiotics concentrations identified that nanoTTO increased the drug accumulation in MDR E. coli by disrupting outer and inner membranes and inhibiting the AcrAB–TolC efflux pump involved in membrane permeability. In addition, nanoTTO was effective in enhancing antibiotic efficacy in the Galleria mellonella infection model and mouse peritonitis model, suggesting a potential strategy against MDR bacterial infections

Additional file 2 of The novel llama-human chimeric antibody has potent effect in lowering LDL-c levels in hPCSK9 transgenic rats

Additional file 2: Fig.S2. The structure schematic diagram and the amino acid sequence of the PCSK9 protein. The PCSK9 protein is composed of signal peptide (amino acid NO. 1-30), pro-domain (NO. 31-152), catalytic domain (NO. 153-425) and C-terminal domain (NO. 426-692). It consists of 692 amino acid residues. The sequence of the PCSK9 protein was shown every 60 amino acid residues in a row

Additional file 5 of The novel llama-human chimeric antibody has potent effect in lowering LDL-c levels in hPCSK9 transgenic rats

Additional file 5: Fig. S4. The stability test by the affinity determination. (A-E) The storage stability test was performed by the affinity determination of the B11-Fc preserved for 1, 4, 7, 10 and 13 weeks. (F) The thermal stability test was performed by the affinity determination of the B11-Fc at 40 °C reaction temperature. Each colored line represents one antibody concentration. The black lines represent the automatic fitting curves by the built-in evaluation software. The binding and dissociation time was set at 180 s/240 s and 240 s respectively, and the protein injection time point was automatically set as 0 s by the built-in evaluation software

Additional file 3 of The novel llama-human chimeric antibody has potent effect in lowering LDL-c levels in hPCSK9 transgenic rats

Additional file 3: Fig. S3. The serological antibody titer test of the immunized llama. The horizontal axis represents five dilution concentrations of the llama serum. The vertical axis represents the OD450 value. ‘(+)’ and ‘(−)’refer to the coating and no-coating of the antigen hPCSK9 to ELISA plates. ‘Pre’ refers to the collected serum before the immunization. ‘Post’ refers to the collected serum 1 month after last immunization. ‘Blank’ refers to the PBS control of the ELISA assay. The star (#) represents serology positive (the OD450 ratio of post-immune serum/pre-immune serum ≥ 2.1)

Additional file 4 of The novel llama-human chimeric antibody has potent effect in lowering LDL-c levels in hPCSK9 transgenic rats

Additional file 4: Table S1. The sequences of the sdAbs

Additional file 1 of The novel llama-human chimeric antibody has potent effect in lowering LDL-c levels in hPCSK9 transgenic rats

Additional file 1: Fig. S1. The LDL-c metabolism mechanisms and the effects of the PCSK9 protein. Under normal circumstances, LDL-c in the serum binds to the LDLR on the liver cell surface and then be be degraded by lysosome. LDLR would recover its activity on the cell surface (the pathway of orange arrows). PCSK9 protein plays a vital role in cholesterol homeostasis by binding to the LDLR. High level PCSK9 competitively binds LDLR with LDL-c, which would cause disorder of LDL-c metabolism. The LDLR would be degraded abnormally intracellularly (the pathway of green arrows). The antibodies (Evolocumab in red or VHH-Fcin blue) can bind the PCSK9, promote LDLR recovery and restore the LDL-c metabolism at some level

Generation and Screening of Antigen-Specific Nanobodies from Mammalian Cells Expressing the BCR Repertoire Library Using Droplet-Based Microfluidics

Nanobodies, also known as VHHs, originate from the serum of Camelidae. Nanobodies have considerable advantages over conventional antibodies, including smaller size, more modifiable, and deeper tissue penetration, making them promising tools for immunotherapy and antibody-drug development. A high-throughput nanobody screening platform is critical to the rapid development of nanobodies. To date, droplet-based microfluidic systems have exhibited improved performance compared to the traditional phage display technology in terms of time and throughput. In realistic situations, however, it is difficult to directly apply the technology to the screening of nanobodies. Requirements of plasma cell enrichment and high cell viability, as well as a lack of related commercial reagents, are leading causes for impeding the development of novel methods. We overcame these obstacles by constructing a eukaryotic display system that secretes nanobodies utilizing homologous recombination and eukaryotic transformation technologies, and the significant advantages are that it is independent of primary cell viability and it does not require plasma cell enrichment in advance. Next, a signal capture system of “SA-beads + Biotin-antigen + nanobody-6 × His + fluorescence-labeled anti-6 × His (secondary antibody)” was designed for precise localization of the eukaryotic-expressed nanobodies in a droplet. Based on this innovation, we screened 293T cells expressing anti-PD-L1 nanobodies with a high positive rate of targeted cells (up to 99.8%). Then, single-cell transcriptomic profiling uncovered the intercellular heterogeneity and BCR sequence of target cells at a single-cell level. The complete complementarity determining region (CDR3) structure was obtained, which was totally consistent with the BCR reference. This study expanded the linkage between microfluidic technology and nanobody applications and also showed potential to accelerate the rapid transformation of nanobodies in the large-scale market