Tackling Vibrio parahaemolyticus in ready-to-eat raw fish flesh slices using lytic phage VPT02 isolated from market oyster.

The opportunistic pathogen V. parahaemolyticus is a major causative agent for seafood-borne illness worldwide. It also causes severe vibriosis in aquaculture animals, affecting seafood production with huge economic loss. These issues are getting worse due to the current global warming in oceans, spread of antibiotic resistance, and changes in consumer preference toward ready-to-eat (RTE) food items including seafood. To answer the urgent need for sustainable biocontrol agents against V. parahaemolyticus, we isolated and characterized a novel lytic bacteriophage VPT02 from market oyster. VPT02 lysed antibiotic resistant V. parahaemolyticus strains including FORC_023. Moreover, it exhibited notable properties as a biocontrol agent suitable for seafood-related settings, like short eclipse/latent periods, high burst size, broad thermal and pH stability, and no toxin/antibiotic resistance genes in the genome. Further comparative genomic analysis with the previously reported homologue phage pVp-1 revealed that VPT02 additionally possesses genes related to the nucleotide scavenging pathway, presumably enabling the phage to propagate quickly. Consistent with its strong in vitro bacteriolytic activity, treatment of only a small quantity of VPT02 (multiplicity of infection of 10) significantly increased the survival rate of V. parahaemolyticus-infected brine shrimp (from 16.7% to 46.7%). When applied to RTE raw fish flesh slices, the same quantity of VPT02 achieved up to 3.9 log reduction of spiked V. parahaemolyticus compared with the phage untreated control. Taken together, these results suggest that VPT02 may be a sustainable anti-V. parahaemolyticus agent useful in seafood-related settings including for RTE items.

The effect of 4-hexylresorcinol on xenograft degradation in a rat calvarial defect model.

BACKGROUND: The objective of this study was to evaluate xenograft degradation velocity when treated with 4-hexylresorcinol (4HR). METHODS: The scapula of a cow was purchased from a local grocery, and discs (diameter 8 mm, thickness 1 mm) were prepared by trephine bur. Discs treated with 4HR were used as the experimental group. Untreated discs were used as the control. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), antibacterial test, endotoxin test, and scanning electron microscopy (SEM) were performed on the discs. In vivo degradation was evaluated by the rat calvarial defect model. RESULTS: The XRD and FT-IR results demonstrated successful incorporation of 4HR into the bovine bone. The experimental disc showed antibacterial properties. The endotoxin test yielded results below the level of endotoxin contamination. In the SEM exam, the surface of the experimental group showed needle-shaped crystal and spreading of RAW264.7 cells. In the animal experiments, the amount of residual graft was significantly smaller in the experimental group compared to the control group (P = 0.003). CONCLUSIONS: In this study, 4HR was successfully incorporated into bovine bone, and 4HR-incorporated bovine bone had antibacterial properties. In vivo experiments demonstrated that 4HR-incorporated bovine bone showed more rapid degradation than untreated bovine bone.

High-Throughput Screening Protocol for the Coupling Reactions of Aryl Halides Using a Colorimetric Chemosensor for Halide Ions.

Mercury complex of 4-(2-pyridylazo)resorcinol (PAR-2Hg(2+)), a halide-ion chemosensor, was prepared and its efficiency as a tool for high-throughput screening (HTS) of transition-metal-catalyzed coupling reactions was investigated. It showed a high selectivity for halide ions. When the PAR-2Hg(2+) complex was used in the Suzuki coupling reaction and C-H activated coupling reaction with aryl bromides, the quantitative and qualitative conversions of aryl halides were obtained from the reaction mixture color change.