In the present study, onion extract was used for green synthesis of iron oxide nanoparticles (Fe-NPs). The X-ray diffraction, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy characterizations demonstrated that the biosynthesized Fe-NPs were mainly composed of low-crystalline or amorphous Fe 2 O 3 with diameter of 19−30 nm. The effect of seed priming with different concentrations of Fe-NPs (20, 40, 80, and 160 mg L −1 ) on seedling growth parameters, photosynthetic pigments, antioxidant potential, metabolites, and hormonal profiles of diploid and triploid watermelon (Citrullus lanatus (Thunb.) Matsum. and Nakai) varieties were studied on the third and eighth days of seedling development. Seed priming with Fe-NPs was safer compared to its bulk counterparts (FeCl 3 and Fe 2 O 3 ) and had no toxic impact on seed germination, seedling development, and chlorophyll biosynthesis at studied concentrations. Untargeted metabolomics studies showed that different Fe-NPs priming treatments distinctly altered the metabolome of diploid and triploid watermelon seedlings. Uniquely, we found that different Fe-NPs priming treatments significantly modulate the 12-oxo phytodienoic acid (OPDA) level in diploid and triploid watermelon seedlings. In conclusion, seed priming with nontoxic Fe-NPs can be applied sustainably to increase nonenzymatic antioxidant potential as well as to prime or induce jasmonates-linked defense responses in watermelon seedlings.

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Gut microbiota plays essential roles in maintaining gut homeostasis. The composition of gut microbes and their metabolites are altered in response to diet and remedial agents such as antibiotics. However, little is known about the effect of antibiotics on the gut microbiota and their volatile metabolites. In this study, we evaluated the impact of a moderate level of ampicillin treatment on volatile fatty acids (VFAs) of gut microbial cultures using an optimized real-time secondary electrospray ionization coupled with high-resolution mass spectrometry (SESI-HRMS). To evaluate the ionization efficiency, different types of electrospray solvents and concentrations of formic acid as an additive (0.01, 0.05, and 0.1%, v/v) were tested using VFAs standard mixture (C2–C7). As a result, the maximum SESI-HRMS signals of all studied m/z values were observed from water with 0.01% formic acid than those from the aqueous methanolic solutions. Optimal temperatures of sample inlet and ion chamber were set at 130 °C and 85 °C, respectively. SESI spray pressure at 0.5 bar generated the maximum intensity than other tested values. The optimized SESI-HRMS was then used for the analysis of VFAs in gut microbial cultures. We detected that the significantly elevated C4 and C7 VFAs in the headspace of gut microbial cultures six hours after ampicillin treatment (1 mg/L). In conclusion, our results suggested that the optimized SESI-HRMS method can be suitable for the analysis of VFAs from gut microbes in a rapid, sensitive, and non-invasive manner.

The use of nanoscale nutrients in agriculture to improve crop productivity has grown in recent years. However, the bioefficacy, safety, and environmental toxicity of nanoparticles (NPs) are not fully understood. Herein, we used onion bulb extract to synthesize manganese oxide nanoparticles (MnO-NPs). X-ray diffraction, X-ray photoelectron spectroscopy, and high-resolution transmission electron microscopy were used for the structural and morphological characterization of synthesized MnO-NPs. The MnO-NPs were oval shape crystalline nanoparticles of Mn2O3 with sizes 22–39 nm. In further studies, we assessed the comparative toxicity of seed priming with MnO-NPs and its bulk counterparts (KMnO4 and Mn2O3), which showed seed priming with MnO-NPs had comparatively less phytotoxicity. Investigating the effect of seed priming with different concentrations of MnO-NPs on the hormonal, phenolic acid, chlorophyll, and antioxidant profiles of watermelon seedlings showed that treatment with 20 mg·L−1 MnO-NPs altered the chlorophyll and antioxidant profiles of seedlings. At ≤40 mg·L−1, MnO-NPs had a remarkable effect on the phenolic acid and phytohormone profiles of the watermelon seedlings. The physiological outcomes of the MnO-NP seed priming in watermelon were genotype-specific and concentration-dependent. In conclusion, the MnO-NPs were safer than their bulk counterparts and could increase crop productivity.

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Metabolomics, especially large-scale untargeted metabolomics, generate massive amounts of data on a regular basis, which often need to be filtered, screened, analyzed and annotated via a variety of approaches. Data-dependent...

As an alternative to pharmacological treatment to diseases, lifestyle interventions, such as dietary changes and physical activities, can help maintain healthy metabolic conditions. Recently, the emerging analyses of volatile organic compounds (VOCs) from breath and short-chain fatty acids (SCFAs) from plasma/feces have been considered as useful tools for the diagnosis and mechanistic understanding of metabolic diseases. Furthermore, diet-induced changes of SCFAs in individuals with diagnosed metabolic abnormalities have been correlated with the composition changes of the gut microbiome. More interestingly, the analysis of exhaled breath (breathomics) has gained attention as a useful technique to measure the human VOC profile altered as a result of dietary interventions. In this mini-review, we examined recent clinical trials that performed promising dietary interventions, SCFAs analysis in plasma/feces, and VOC profile analysis in exhaling breath to understand the relationship between dietary intervention and metabolic health.

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