Nonlinear metasurface engineering with disordered gold nanorods on ITO: a cost-effective approach to broadband response, polarization-independence, and weak nonlinear index dispersion.

The strong coupling of epsilon-near-zero materials with nanoantennas has demonstrated enhanced nonlinear optical responses, yet practical challenges persist. Here, we propose an alternative: an ultrathin metasurface featuring broadband response with a weakly dispersive nonlinear index, achieved through a simple implementation. Our metasurface, comprising a disordered gold nanorod array on indium tin oxide, exhibits polarization-independent behavior and a large average nonlinear refractive index of 5 cm2/GW across a broad wavelength range (1000-1300 nm). Enhanced performance is attributed to the weak coupling between gold nanorods and indium tin oxide, offering a cost-effective method for nonlinear optical metasurfaces and a flexible design in nanophotonic applications.

AtPFA-DSP3, an atypical dual-specificity protein tyrosine phosphatase, affects salt stress response by modulating MPK3 and MPK6 activity.

Protein phosphorylation, especially serine/threonine and tyrosine phosphorylation, plays significant roles in signalling during plant growth and development as well as plant responses to biotic or abiotic stresses. Dual-specificity protein tyrosine phosphatases dephosphorylate components of these signalling pathways. Here, we report that an atypical dual-specificity protein tyrosine phosphatase, AtPFA-DSP3 (DSP3), negatively affects the response of plants to high-salt conditions. A DSP3 loss-of-function mutant showed reduced sensitivity to salt treatment. DSP3 was primarily localized in nuclei and was degraded during salt treatment. Compared to wild type, the level of ROS was lower in the dsp3 mutant and higher in plants ectopically expressing DSP3, indicating that higher DSP3 level was associated with increased ROS production. DSP3 interacted with and dephosphorylated MPK3 and MPK6. Genetic analyses of a dsp3mpk3 double mutant revealed that DSP3's effect on salt stress depends on MPK3. Moreover, the phosphatase activity of DSP3 was required for its role in salt signalling. These results indicate that DSP3 is a negative regulator of salt responses in Arabidopsis by directly modulating the accumulation of phosphorylated MPK3 and MPK6.

The response regulator ArcA enhances biofilm formation in the vpsT manner under the anaerobic condition in Vibrio cholerae.

Vibrio cholerae, the agent of severe diarrheal disease cholera, is known to form biofilm to persist in the environmental and the host,s intestines. The bacteria execute a complex regulatory pathway producing virulence factors that allow colonization and cause disease in response to environmental signals in the intestine, including low oxygen-limited condition. VpsR and VpsT are primary regulators of the biofilm formation-regulatory network. In this study, we determined that anaerobic induction enhanced biofilm formation via the two component system, ArcB/A, which functions as a positive regulator of toxT expression. The biofilm formation has reduced approximately 2.4-fold in the ΔarcA mutant compared to the wild type in anaerobic condition. Chip-qPCR and EMSA assays confirmed that ArcA can bind directly to the vpsT promoter and then activates the expression of biofilm formation related genes, vpsA-K and vpsL-Q. Meanwhile, the ΔarcA mutant decreased the ability of colonization in intestine with CI (competition index) of 0.27 compared to wild type strain. These results suggest that ArcA links the expression of virulence and biofilm synthesis genes during anaerobic condition, and contributes to understand the complex relationship between biofilm formation and the intestinal signals during infection.

O-Antigen Gene Clusters of Plesiomonas shigelloides Serogroups and Its Application in Development of a Molecular Serotyping Scheme.

Plesiomonas shigelloides is a Gram-negative, flagellated, rod-shaped, ubiquitous, and facultative anaerobic bacterium. It has been isolated from various sources, such as freshwater, surface water, and many wild and domestic animals. P. shigelloides is associated with diarrheal diseases of acute secretory gastroenteritis, an invasive shigellosis-like disease, and a cholera-like illness in humans. At present, 102 somatic antigens and 51 flagellar antigens of P. shigelloides have been recognized; however, very little is known about variations of O-antigens among P. shigelloides species. In this study, 12 O-antigen gene clusters of P. shigelloides, O2H1a1c (G5877), O10H41 (G5892), O12H35 (G5890), O23H1a1c (G5263), O25H3 (G5879), O26H1a1c (G5889), O32H37 (G5880), O33H38 (G5881), O34H34 (G5882), O66H3 (G5270), O75H34 (G5885), and O76H39 (G5886), were sequenced and analyzed. The genes that control O-antigen synthesis are present as chromosomal gene clusters that maps between rep and aqpZ, and most of the synthesis and translocation of OPS (O-specific polysaccharide) belongs to Wzx/Wzy pathway with the exception of O12, O25, and O66, which use the ATP-binding cassette (ABC) transporter pathway. Phylogenetic analysis of wzx and wzy show that the wzx and wzy genes are specific to individual O-antigens and can be used as targets in molecular typing. Based on the sequence data, an O-antigen specific suspension array that detects 12 distinct OPS' has been developed. This is the first report to catalog the genetic features of P. shigelloides O-antigen variations and develop a suspension array for the molecular typing. The method has several advantages over traditional bacteriophage and serum agglutination methods and lays the foundation for easier identification and detection of additional O-antigen in the future.