Transcriptome Analysis Reveals the Growth Promotion Mechanism of Enteropathogenic Escherichia coli Induced by Black Phosphorus Nanosheets

An LF-NMR homogeneous sensor for highly sensitive and precise detection of E. coli based on target-triggered CuAAC click reaction

In this study, a low field nuclear magnetic resonance (LF-NMR) homogeneous sensor was constructed for detection of Escherichia coli (E. coli) based on the copper metabolism of E. coli triggered click reaction. When live E. coli was present, a large amount of Cu2+ ions were transformed into Cu+ via copper metabolism, which then catalyzed a Cu+-catalyzed azide-alkyne cycloaddition (CuAAC) reaction between two materials, azide group modified gadolinium oxide nanorods (Gd2O3-Az) and PA-GO@Fe3O4 i.e., graphene oxide (GO) loaded with large amounts of alkynyl (PA) groups and Fe3O4 nanoparticles simultaneously. After magnetic separation, unbound Gd2O3-Az was dissolved by added hydrochloric acid (HCl) to generate homogeneous Gd3+ solution, enabling homogeneous detection of E. coli. Triple signal amplification was achieved through the CuAAC reaction induced by E. coli copper metabolism, functional nanomaterials, and HCl assisted homogeneous detection. Under the optimal experimental conditions, the linear range and limit of detection (LOD) for E. coli were 10-1.0 × 107 CFU/mL and 3.5 CFU/mL, respectively, and the relative standard deviations (RSDs) were all less than 2.8 %. In addition, the sensor has satisfactory selectivity, stability and practical sample application capability, providing a new approach for the LF-NMR detection of food-borne pathogenic bacteria.

Phthalates Boost Natural Transformation of Extracellular Antibiotic Resistance Genes through Enhancing Bacterial Motility and DNA Environmental Persistence

The environmental dissemination of extracellular antibiotic resistance genes (eARGs) in wastewater and natural water bodies has aroused growing ecological concerns. The coexisting chemical pollutants in water are known to markedly affect the eARGs transfer behaviors of the environmental microbial community, but the detailed interactions and specific impacts remain elusive so far. Here, we revealed a concentration-dependent impact of dimethyl phthalate (DMP) and several other types of phthalate esters (common water pollutants released from plastics) on the natural transformation of eARGs. The DMP exposure at an environmentally relevant concentration (10 μg/L) resulted in a 4.8-times raised transformation frequency of Acinetobacter baylyi but severely suppressed the transformation at a high concentration (1000 μg/L). The promotion by low-concentration DMP was attributed to multiple mechanisms, including increased bacterial mobility and membrane permeability to facilitate eARGs uptake and improved resistance of the DMP-bounded eARGs (via noncovalent interaction) to enzymatic degradation (with suppressed DNase activity). Similar promoting effects of DMP on the eARGs transformation were also found in real wastewater and biofilm systems. In contrast, higher-concentration DMP suppressed the eARGs transformation by disrupting the DNA structure. Our findings highlight a potentially underestimated eARGs spreading in aquatic environments due to the impacts of coexisting chemical pollutants and deepen our understanding of the risks of biological-chemical combined pollution in wastewater and environmental water bodies.

Recent Advances of Emerging Metal-Containing Two-Dimensional Nanomaterials in Tumor Theranostics

In recent years, metal-containing two-dimensional (2D) nanomaterials, among various 2D nanomaterials have attracted widespread attention because of their unique physical and chemical properties, especially in the fields of biomedical applications. Firstly, the review provides a brief introduction to two types of metal-containing 2D nanomaterials, based on whether metal species take up the major skeleton of the 2D nanomaterials. After this, the synthetical approaches are summarized, focusing on two strategies similar to other 2D nanomaterials, top-down and bottom-up methods. Then, the performance and evaluation of these 2D nanomaterials when applied to cancer therapy are discussed in detail. The specificity of metal-containing 2D nanomaterials in physics and optics makes them capable of killing cancer cells in a variety of ways, such as photodynamic therapy, photothermal therapy, sonodynamic therapy, chemodynamic therapy and so on. Besides, the integrated platform of diagnosis and treatment and the clinical translatability through metal-containing 2D nanomaterials is also introduced in this review. In the summary and perspective section, advanced rational design, challenges and promising clinical contributions to cancer therapy of these emerging metal-containing 2D nanomaterials are discussed.