Discovery of new dibenzodiazepine derivatives as antibacterials against intracellular bacteria.

The emergence and spread of multidrug-resistant bacteria underscore the critical need for novel antibacterial interventions. In our screening of 12 synthesized thienobenzodiazepines, pyridobenzodiazepines, and dibenzodiazepines, we successfully identified a small molecule compound SW33. Notably, SW33 demonstrated potent inhibitory activity against intracellular multidrug-resistant and fluoroquinolone-resistant strains of S. typhimurium in both macrophages and epithelial cells. Furthermore, SW33 was also effective against intramacrophagic Salmonella typhi, Yersinia enterocolitica, and Listeria monocytogenes. These significant findings suggest that SW33 possesses broad-spectrum activity against intracellular bacteria.

Repurposing the tyrosine kinase inhibitor nilotinib for use against intracellular multidrug-resistant Salmonella Typhimurium.

BACKGROUND/PURPOSE: The increasing incidence of infections caused by multidrug-resistant Salmonella enterica has become a serious threat to global public health. Here, we found that the tyrosine kinase inhibitor nilotinib exhibits antibacterial activity against intracellular S. enterica serovar Typhimurium in RAW264.7 macrophages. Thus, we aimed to pharmacologically exploit the anti-intracellular Salmonella activity of nilotinib and to elucidate its mechanism of action. METHODS: The antibacterial activity of the compounds was assessed by high-content analysis (HCA) and intracellular CFU, minimum inhibitory concentration (MIC), and bacterial growth assays. The cytotoxicity of the compounds was evaluated by HCA and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) cell viability assays. The levels of cellular AMPK, phospho-AMPK, Atg7 and ß-actin were determined by immunoblotting. RESULTS: The screen identified two small molecule compounds (SCT1101 and SCT1104) with potent activity against intracellular S. Typhimurium. Moreover, SCT1101 and SCT1104 enhanced the efficacy of ciprofloxacin and cefixime against intracellular S. Typhimurium. However, only SCT1101 exhibited activity against intracellular MDR and fluoroquinolone-resistant S. Typhimurium isolates. Subsequent mechanistic studies showed that neither of these nilotinib derivatives increased the phospho-AMPK level in RAW264.7 cells. Neither the AMPK inhibitor compound C nor SBI-0206965 reversed the inhibitory effects of SCT1101 and SCT1104 on intracellular Salmonella. Furthermore, neither blockade of autophagy by 3-MA nor shRNA-mediated knockdown of Atg7 protein expression in RAW264.7 cells affected the antibacterial activity of SCT1101 and SCT1104. CONCLUSION: The structure of nilotinib could be used to develop novel therapeutics for controlling MDR S. Typhimurium infections.

Discovery of antipsychotic loxapine derivatives against intracellular multidrug-resistant bacteria.

The emergence and spread of multidrug-resistant bacteria highlight the need for new antibacterial interventions. A screening of 24 newly synthesized dibenzoxazepines identified a small molecule compound, SW14, with potent inhibitory activity against intracellular multidrug-resistant and fluoroquinolone-resistant strains of S. typhimurium in macrophages and epithelial cells. Moreover, intra-macrophagic Salmonella typhi, Yersinia enterocolitica, and Listeria monocytogenes and methicillin-resistant Staphylococcus aureus are also susceptible to SW14. Overall, our findings suggest that SW14 has a broad-spectrum activity against intracellular bacteria.

Heavily Doped and Highly Conductive Hierarchical Nanoporous Graphene for Electrochemical Hydrogen Production.

Heavy chemical doping and high electrical conductivity are two key factors for metal-free graphene electrocatalysts to realize superior catalytic performance toward hydrogen evolution. However, heavy chemical doping usually leads to the reduction of electrical conductivity because the catalytically active dopants give rise to additional electron scattering and hence increased electrical resistance. A hierarchical nanoporous graphene, which is comprised of heavily chemical doped domains and a highly conductive pure graphene substrate, is reported. The hierarchical nanoporous graphene can host a remarkably high concentration of N and S dopants up to 9.0 at % without sacrificing the excellent electrical conductivity of graphene. The combination of heavy chemical doping and high conductivity results in high catalytic activity toward electrochemical hydrogen production. This study has an important implication in developing multi-functional electrocatalysts by 3D nanoarchitecture design.

Three-dimensional bicontinuous nanoporous materials by vapor phase dealloying.

Three-dimensional bicontinuous open (3DBO) nanoporosity has been recognized as an important nanoarchitecture for catalysis, sensing, and energy storage. Dealloying, i.e., selectively removing a component from an alloy, is an efficient way to fabricate nanoporous materials. However, current electrochemical and liquid-metal dealloying methods can only be applied to a limited number of alloys and usually require an etching process with chemical waste. Here, we report a green and universal approach, vapor-phase dealloying, to fabricate nanoporous materials by utilizing the vapor pressure difference between constituent elements in an alloy to selectively remove a component with a high partial vapor pressure for 3DBO nanoporosity. We demonstrate that extensive elements, regardless of chemical activity, can be fabricated as nanoporous materials with tunable pore sizes. Importantly, the evaporated components can be fully recovered. This environmentally friendly dealloying method paves a way to fabricate 3DBO nanoporous materials for a wide range of structural and functional applications.

A simpler and more cost-effective peptide biosynthetic method using the truncated GST as carrier for epitope mapping.

There is a need to develop better methods for epitope mapping and/or identification of antibody-recognizing motifs. Here, we describe improved biosynthetic peptide (BSP) method using a newly developed plasmid pXXGST-3 as vector, which has a viral E7 gene in the cloning sites of pXXGST-1. It is crucial to employ pXXGST-3 instead of pXXGST-1, since it makes use of the BSP method simpler and easier to perform, and more cost-effective for epitope mapping. These merits are embodied in two aspects: i) convenient recovery of double enzyme-digested product due to the existence of 315 bp inserted between BamH I and Sal I sites, and thus greatly reducing the production of self-ligation clones, and ii) no longer requiring control protein when screening recombinant (r-) clones expressing 8/18mer peptides by running polyacrylamide gel electrophoresis. The protocol involves the following core steps: (i) design of plus and minus strands of DNA fragments encoding overlapping 8/18mer peptides; (ii) chemical synthesis of the designed DNA fragments; (iii) development of r-clones using pXXGST-3 vector expressing each 8/18mer peptide fused with truncated GST188 protein; (iv) screening r-clones by running the cell pellets from each induced clone on SDS-PAGE gel followed by sequencing of inserted DNA fragments for each verified r-clone; and (v) Western blotting with either monoclonal antibodies or polyclonal antibodies. This improved GST188-BSP method provides a powerful alternative tool for epitope mapping.

Correlation between Chemical Dopants and Topological Defects in Catalytically Active Nanoporous Graphene.

The interplay between chemical dopants and topological defects plays a crucial role in electrocatalysis of doped graphene. By systematically tuning the curvatures, thereby the density of topological defects, of 3D nanoporous graphene, the intrinsic correlation of topological defects with chemical doping contents and dopant configurations is revealed, shining lights into the structural and chemical origins of HER activities of graphene.

Simple and rapid human papillomavirus genotyping method by restriction fragment length polymorphism analysis with two restriction enzymes.

Cervical cancer, the third most common cancer that affects women worldwide, is caused by the human papillomavirus (HPV) and is treatable when detected at an early stage. To date, more than 100 different HPV types have been described, and the development of simple, low-cost, and accurate methods to distinguish HPV genotypes is highly warranted. In this study, an HPV genotyping assay based on polymerase chain reaction (PCR) was evaluated. This method involved the use of MY09/11 primers followed by restriction fragment length polymorphism (RFLP) analysis with the restriction enzymes HpyCH4V and NlaIII. Cervical specimens preserved using CytoRich Blue fluid were collected from 1,134 female volunteers for HPV detection, and 1,111 valid samples were amplified using PCR. The PCR method was sensitive enough to detect 25 copies of HPV18, and three copies of HPV16. Out of 202 PCR-positive samples, HPV genotypes were determined in 189 samples (93.6%) by this RFLP method. Results were then evaluated further by capillary sequencing method. Concordant results between the two tests were as high as 96.0%. Thirteen samples, which tested negative with RFLP, were verified as non-specific amplifications with PCR. In conclusion, this PCR-RFLP method using restriction enzymes HpyCH4V and NlaIII is simple, non-labor intensive, and is applicable for the inexpensive determination of HPV genotypes in clinical samples.