Search for: All records

Acinetobacters pose a significant threat to human health, especially those with weakened immune systems. Type IV pili of acinetobacters play crucial roles in virulence and antibiotic resistance. Single-stranded RNA bacteriophages target the bacterial retractile pili, including type IV. Our study delves into the interaction betweenAcinetobacterphage AP205 and type IV pili. Using cryo-electron microscopy, we solve structures of the AP205 virion with an asymmetric dimer of maturation proteins, the nativeAcinetobactertype IV pili bearing a distinct post-translational pilin cleavage, and the pili-bound AP205 showing its maturation proteins adapted to pilin modifications, allowing each phage to bind to one or two pili. Leveraging these results, we develop a 20-kilodalton AP205-derived protein scaffold targeting type IV pili in situ, with potential for research and diagnostics.

Water-based coherent detection of broadband terahertz (THz) wave has been recently proposed with superior performances, which can alleviate the limited detection bandwidth and high probe laser energy requirement in the solid- and air-based detection schemes, respectively. Here, we demonstrate that the water-based detection method can be extended to the aqueous salt solutions and the sensitivity can be significantly enhanced. The THz coherent detection signal intensity scales linearly with the third-order nonlinear susceptibilityχ⁽³⁾or quadratically with the linear refractive indexη₀of the aqueous salt solutions, while the incoherent detection signal intensity scales quadratically withχ⁽³⁾or quartically withη₀, proving the underlying mechanism is the four-wave mixing. Both the coherent and incoherent detection signal intensities appear positive correlation with the solution concentration. These results imply that the liquid-based THz detection scheme could provide a new technique to measureχ⁽³⁾and further investigate the physicochemical properties in the THz band for various liquids.