Rabbit Anti-Human FES (C-terminal) Polyclonal antibody

We developed a top-down strategy to characterize an antimicrobial, oxidizing sanitizer, which has diverse proposed applications including surface-sanitization of fresh foods, and with benefits for water resilience. The strategy involved finding quenchers of antimicrobial activity then antimicrobial mode of action, by identifying key chemical reaction partners starting from complex matrices, narrowing down reactivity to specific organic molecules within cells. The sanitizer electrolyzed-water (EW) retained partial fungicidal activity against the food-spoilage fungusAspergillus nigerat high levels of added soils (30-750 mg mL(-1)), commonly associated with harvested produce. Soil with high organic load (98 mg g(-1)) gave stronger EW inactivation. Marked inactivation by a complex organics mix (YEPD medium) was linked to its protein-rich components. Addition of pure proteins or amino acids (<= 1 mg mL(-1)) fully suppressed EW activity. Mechanism was interrogated further with the yeast model, corroborating marked suppression of EW action by the amino acid methionine. Pre-culture with methionine increased resistance to EW, sodium hypochlorite, or chlorine-free ozonated water. Overexpression of methionine sulfoxide reductases (which reduce oxidized methionine) protected against EW. Fluoroprobe-based analyses indicated that methionine and cysteine inactivate free chlorine species in EW. Intracellular methionine oxidation can disturb cellular FeS-clusters and we showed that EW treatment impairs FeS-enzyme activity. The study establishes the value of a top-down approach for multi-level characterization of sanitizer efficacy and action. The results reveal proteins and amino acids as key quenchers of EW activity and, among the amino acids, the importance of methionine oxidation and FeS-cluster damage for antimicrobial mode-of-action.

The key to understand the origin of banded iron-formations (BIFs) formed in 3.8-2.5 Ga is to identify the oxidation mechanism of Fe2+ in anoxic oceans. In this study, we proposed a likely pyrite-induced Fe2+ oxidation mechanism for near-vent, hydrothermal fluid-dominated BIFs. A series of important environmental conditions including light intensity, wavelength and pH were considered and monitored to check their effects on the production of reactive oxygen species (ROS) in anaerobic pyrite suspensions. By quantifying the concentration of center dot OH and H2O2, we observed a stable ROS production as induced by pyrite in both dark and light under a wide pH range. Interestingly, light significantly promoted the producing rate of ROS, which increased with the light intensity, but was poorly correlated with the light wavelength. In addition, the producing rate of ROS remarkably increased as the pH decreased from 6.0 to 3.0, suggesting the acidic conditions were more beneficial for ROS generation. The production of ROS could be attributed to the semiconducting photocatalysis of pyrite, and the sulfur-deficient defect on its surface. Based on the sulfur content of volatiles in modern submarine basalts and black smokers, we assumed that the concentration of H2S in Archean hydrothermal fluids ranged from 0.5 to 55 mmol/kg. Combined with the experimental results of H2O2 producing rates under 150 mW/cm(2) irradiation at pH 3.0 and under dark at pH 6.0, the H2O2 flux of 6.9 x 10(5) -1.1 x 10(9) mol/yr could be estimated in a thermal flow. This value covered the amount of H2O2 required for Fe2+ oxidation in Archean oceans to form the near-vent, hydrothermal fluid-dominated BIFs (1.7 x 10(6) -1.3 x 10(7) mol/yr). The reaction kinetics revealed that the conversion of amorphous FeS into pyrite under hydrothermal conditions was very quick, while the consumption of H2O2 during the back-reaction with pyrite was quite limited. This view can explain why this type of BIFs typically occurs as intercalated layers in volcanic rocks and is associated with volcanogenic massive sulfide ore (VMS)-type deposits.