Search

As a natural product isolated from thyme oil in thyme, thymol (2‐isopropyl‐5‐methylphenol) harbors antiviral, antioxidant, and other properties, and thus could be potentially used for the treatment of various diseases. However, the function of thymol has not been comprehensively studied. Here, we applied an inverse molecular docking approach to identify unappreciated functions of thymol. Potential targets of thymol in humans were identified by the server of DRAR‐CPI, and targets of interest were then assessed by GO and KEGG pathway analysis. Subsequently, homologous proteins of these targets in Caenorhabditis elegans were identified by Blast tool, and their three‐dimensional structures were achieved using Swiss‐Model workspace. Interaction between thymol and the targeted proteins in worms was verified using AutoDock 4.0. Analyses of the targets revealed that thymol could be potentially involved in the glycolysis/gluconeogenesis and fatty acid degradation pathways. To verify the activity of thymol on lipid deposition in vivo, the C. elegans model was established. The lipid content of nematodes induced by high‐dose glucose was determined by Oil Red O and Nile Red staining, and gene expression was assessed by qRT‐PCR. The results showed that thymol might lead to the acceleration of β‐oxidation by upregulating cpt‐1, aco, fabp, and tph‐1, causing the descent of lipid content in nematodes. Our findings indicated that thymol could be potentially used for the treatment of chronic metabolic diseases associated with increased fatty acid deposition. [ABSTRACT FROM AUTHOR]

As a destructive fungus-like plant pathogen, the oomycete Phytophthora capsici is unable to synthesize its own ergosterol as the potential target of fungicide cinnamaldehyde (CA). In this study, CA exerted efficient inhibitory effects on both mycelial growth (EC50=0.75 mM) and zoospore germination (MIC=0.4 mM) of P. capsici. CA-induced immediate Ca2+ efflux from zoospores could be confirmed by the rapid decrease in intracellular Ca2+ content determined by using Fluo-3 AM and the increase in extracellular Ca2+ concentration determined by using ICP-AES (inductively coupled plasma atomic emission spectrometry). Blocking Ca2+ influx with ruthenium red and verapamil led to a higher level of CA-induced Ca2+ efflux, suggesting the simultaneous occurrence of Ca2+ influx along with the Ca2+ efflux under CA exposure. Further results showed that EGTA-induced decrease in intracellular Ca2+ gave rise to the impaired vitality of P. capsici while the addition of exogenous Ca2+ could suppress the growth inhibitory effect of CA. These results suggested that Ca2+ efflux played an important role in CA-induced growth inhibition of P. capsici. The application of 3-phenyl-1-propanal, a CA analog without α,β- unsaturated bond, resulted in a marked Ca2+ influx in zoospores but did not show any growth inhibitory effects. In addition, exogenous cysteine, an antagonist against the Michael addition (the nucleophilic addition of a carbanion or another nucleophile) between CA and its targets, could attenuate CA-induced growth inhibition of P. capsici by suppressing Ca2+ efflux. Our results suggest that CA inhibits the growth of P. capsici by stimulating a transient Ca2+ efflux via Michael addition, which provides important new insights into the antimicrobial action of CA. [ABSTRACT FROM AUTHOR]

Persisters are tolerant to multiple antibiotics, and widely distributed in bacteria, fungi, parasites, and even cancerous human cell populations, leading to recurrent infections and relapse after therapy. In this study, we investigated the potential of cinnamaldehyde and its derivatives to eradicate persisters in Escherichia coli. The results showed that 200 μg/ml of alpha-bromocinnamaldehyde (Br-CA) was capable of killing all E. coli cells during the exponential phase. Considering the heterogeneous nature of persisters, multiple types of persisters were induced and exposed to Br-CA. Our results indicated that no cells in the ppGpp-overproducing strain or TisB-overexpressing strain survived the treatment of Br-CA although considerable amounts of persisters to ampicillin (Amp) and ciprofloxacin (Cip) were induced. Chemical induction by carbonyl cyanide m-chlorophenylhydrazone (CCCP) led to the formation of more than 10% persister to Amp and Cip in the entire population, and Br-CA still completely eradicated them. In addition, the cells in the stationary phase, which are usually highly recalcitrant to antibiotics treatment, were also completely eradicated by 400 μg/ml of Br-CA. Further studies showed that neither thiourea (hydroxyl-radical scavenger) nor DPTA (Fe3+ chelator to block the hydroxyl-radical) affected the bactericidal efficiency of the Br-CA to kill E. coli, indicating a ROS-independent bactericidal mechanism. Taken together, we concluded that Br-CA compound has a novel bactericidal mechanism and the potential to mitigate antibiotics resistance crisis. [ABSTRACT FROM AUTHOR]

Thymol is a plant-derived natural compound with antimicrobial activity. However, we have little knowledge about the application of thymol in agriculture. One of the limitations is the high volatility and low aqueous solubility of thymol. Tomato gray mold caused by Botrytis cinerea is one of the most devastating postharvest diseases. In this study, we prepared a nano-emulsion of thymol (named as Nano-Thy) to form a stable O/W (oil in water) microemulsion. In vitro experiments showed that Nano-Thy had antifungal activity against B. cinerea by inhibiting mycelial growth and spore germination. Nano-Thy induced ROS accumulation in mycelia, further leading to lipid peroxidation, cell membrane damage, and subsequent cell death. Nano-Thy significantly prevented the infection of B. cinerea on fresh tomato fruits. Finally, we discussed the mechanisms and their significance in controlling postharvest disease of fruit crops. [ABSTRACT FROM AUTHOR]

Acne vulgaris is a common chronic inflammatory skin disease involving Cutibacterium acnes with other skin commensals such as Staphylococcus aureus and Candida albicans in the anaerobic and lipid-rich conditions of pilosebaceous units. These microbes readily form multispecies biofilms that are tolerant of traditional antibiotics as well as host immune systems. The phytopigment alizarin was previously found to prevent biofilm formation by S. aureus and C. albicans strains under aerobic conditions. Hence, we hypothesized that alizarin might control C. acnes and multispecies biofilm development. We found that under anaerobic conditions, alizarin efficiently inhibited single biofilm formation and multispecies biofilm development by C. acnes, S. aureus, and C. albicans without inhibiting planktonic cell growth. Alizarin increased the hydrophilicities of S. aureus and C. albicans cells, decreased lipase production by S. aureus, diminished agglutination by C. acnes, and inhibited the aggregation of C. albicans cells. Furthermore, the co-administration of alizarin and antibiotics enhanced the antibiofilm efficacies of alizarin against C. acnes. A transcriptomic study showed that alizarin repressed the transcriptions of various biofilm-related genes such as lipase, hyaluronate lyase, adhesin/invasion-related, and virulence-related genes of C. acnes. Furthermore, alizarin at 100 µg/mL prevented C. acnes biofilm development on porcine skin. Our results show that alizarin inhibits multispecies biofilm development by acne-causing microbes and suggest it might be a useful agent for treating or preventing C. acnes-causing skin diseases. [ABSTRACT FROM AUTHOR]

A comprehensive lipidomic analysis of the lipids extracted from grass carp bones, black carp bones, shrimp shells, and crab shells was performed in this study. First, HPLC analysis revealed that the lipids extracted from shrimp and crab shells contained 60.65% and 77.25% of diacylglycerols, respectively. Second, GC‐MS analysis identified 18 fatty acid species in the lipids extracted from fish bones and crustacean shells, in which polyunsaturated fatty acids (PUFAs) were highly enriched. PUFAs were present at 45.43% in the lipids extracted from shrimp shells. Notably, the lipids extracted from shrimp and crab shells contained a considerable amount of eicosapentaenoic acids and docosahexaenoic acids. Finally, multidimensional mass spectrometry‐based shotgun lipidomics showed that various lipids including acetyl‐L‐carnitine, sphingomyelin (SM), lysophosphatidylcholine, and phosphatidylcholine (PC) were all identified in the lipid samples, but PC and SM were the most abundant. Specifically, the total content of PC in shrimp shells was as high as 6.145 mmol/g. More than 35 species of PC were found in all samples, which were more than other lipids. This study is expected to provide a scientific basis for the application of freshwater fish bones and crustacean shells in food, medicine, and other fields. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the performance of volatile organic compounds (VOCs) for evolution monitoring and early detection of Aspergillus flavus (A. flavus) contamination in walnuts. We successfully applied headspace–gas chromatography–ion mobility spectrometry (HS‐GC‐IMS) to evaluate walnut VOC changes caused by A. flavus contamination. A total of 48 VOCs were identified in walnuts contaminated with A. flavus. After identification of VOCs, a heat map and principal component analysis (PCA) highlighted ethyl acetate‐D, 3‐methyl‐2‐butanol, and cyclohexanone as potential biomarkers specific to A. flavus contamination in walnuts. These results provided valid targets for the development of sensors to evaluate the early mold contamination in stored walnuts. [ABSTRACT FROM AUTHOR]

The postharvest quality of kiwifruit is critical for consumer satisfaction and reducing waste. Ready-to-eat kiwifruit lacks a consistent quality standard, and monitoring its quality is essential. This study proposes a novel and smart strategy to monitor the quality of mature kiwifruits stored at room temperature using image recognition application on a mobile phone. The study correlates the storage time, quality indexes, and volatile flavor compounds with RGB (RGB stands for Red, Green, and Blue) values readouts from photos. Results show that central B/G (The ratio of B to G in the center of kiwifruit) values positively correlate with vitamin C and negatively correlate with weight loss rate. Specific volatile compounds, such as methyl benzoate, methyl butyrate, ethyl benzoate, ethyl butyrate, and ethyl acetate, can serve as markers for evaluating kiwifruit quality and freshness. Furthermore, firmness strongly correlates with the volatile gases hexanal and trans -2-hexenoic acid. Chroma values and specific volatiles can serve as early warning indicators to monitor the quality of postharvest kiwifruit. The study provides a quick and facile method to evaluate kiwifruit quality stored at room temperature, providing a basis for the development of ready-to-eat kiwifruit. This strategy benefits both consumers and processing plants in reducing waste and improving kiwifruit quality. [Display omitted] • Quality of kiwifruits was correlated with RGB values of smart phone photos. • A potential quick evaluation method for freshness of kiwifruits was provided. • We provides a monitoring standard for ready-to-eat kiwifruit production. • Analyzed the correlation between quality and color values kiwifruit during storage. [ABSTRACT FROM AUTHOR]

• The bactericidal effect was positively correlated with the blue light dose. • Blue light damaged the cell membrane and caused a reactive oxygen species burst. • RNA-seq analysis was used to characterize the changes of metabolic pathways. • Ultrasonic field for 15 min assisted by blue light sterilization is more effective. • Blue light or ultrasonic field treatment maintained the quality of salmon. Vibrio parahaemolyticus is a typical marine bacterium, which often contaminates seafood and poses a health risk to consumers. Some non-thermal sterilization technologies, such as ultrasonic field (UF) and blue light (BL) irradiation, have been widely used in clinical practice due to their efficiency, safety, and avoidance of drug resistance, but their application in food preservation has not been extensively studied. This study aims to investigate the effect of BL on V. parahaemolyticus in culture media and in ready-to-eat fresh salmon, and to evaluate the killing effectiveness of the UF combined with BL treatment on V. parahaemolyticus. The results showed that BL irradiation at 216 J/cm2 was effective in causing cell death (close to 100%), cell shrinkage and reactive oxygen species (ROS) burst in V. parahaemolyticus. Application of imidazole (IMZ), an inhibitor of ROS generation, attenuated the cell death induced by BL, indicating that ROS were involved in the bactericidal effects of BL on V. parahaemolyticus. Furthermore, UF for 15 min enhanced the bactericidal effect of BL at 216 J/cm2 on V. parahaemolyticus , with the bactericidal rate of 98.81%. In addition, BL sterilization did not affect the color and quality of salmon, and the additive UF treatment for 15 min did not significant impact on the color of salmon. These results suggest that BL or UF combined with BL treatment has potential for salmon preservation, however, it is crucial to strictly control the intensity of BL and the duration of UF treatment to prevent reducing the freshness and brightness of salmon. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes frequently causes Listeriosis in humans and animals. In present study, we discovered that in the presence of FeSO 4 , L. monocytogenes became viable but non-culturable (VBNC), and remained virulent to Caenorhabditis elegans. The killing assay indicated that these VBNC cells kept sensitive to tetracycline, differing from dormant cells. Transcriptomic analysis revealed more gene transcription occurrence in the VBNC cells compared to dormant cells, involving stress response and ribosome binding. No ferroptosis hallmarks were observed in the VBNC cells, whereas the application of either intracellular Fe2+ chelator or the ferroptosis inhibitor arrested the formation of VBNC state by FeSO 4 , as well as by Benzakonium chloride or Haz-Tab. This implicated the universal involvement of intracellular Fe2+ and other cascades related to ferroptosis in the formation of VBNC state in L. monocytogenes. Taken together, we discovered an iron-induced VBNC state in L. monocytogenes , and provided clues to further understanding their potential risks. [ABSTRACT FROM AUTHOR]

Hydrogels loaded with ampicillin, vancomycin or other antibiotics are one of the most widely used therapeutic agents for keratitis caused by Staphylococcus aureus. However, emergence of methicillin-resistant S. aureus (MRSA) makes infections harder to be treated by antibiotic-based hydrogels, urging the development of novel antibacterial materials. Inspired by mammalian ferroptosis, we determined the bactericidal effects of ferrous sulfate (FeSO 4) on S. aureus , and evaluated the therapeutic potential of FeSO 4 -loaded hydrogel in a mouse keratitis model. The results showed that FeSO 4 facilitated ferroptosis-like cell death in S. aureus with the key characteristics of reactive oxygen species (ROS) generation and lipid peroxidation. Notably, FeSO 4 also efficiently killed persisters and MRSA, and eliminated biofilms of S. aureus. RNA profiles demonstrated that ferroptosis-related genes were significantly up-regulated, and the genes responsible for cell wall and cell membrane biosynthesis were down-regulated after exposure to Fe2+, supporting the occurrence of ferroptosis and cell lysis. We further prepared a FeSO 4 -loaded hydrogel by using hyaluronic acid (HA) and ascorbate. The FeSO 4 hydrogel has the characteristics of injectability, self-healing, uniform distribution of Fe2+ in the three-dimensional gel structure, appropriate fluidity, high-water retention, high efficacy to kill MRSA, and excellent biocompatibility. In a mouse keratitis model, we showed that treatment of animals with FeSO 4 hydrogel led to a rapid recovery of from keratitis, prevented the dissimilation of MRSA to the lung, and alleviated systemic inflammation, demonstrating the therapeutic potential of FeSO 4 hydrogel. Taken together, our results indicated that FeSO 4 hydrogel is a promising alternative to current antibiotics-dependent therapeutic materials for the treatment of infections by MRSA. [ABSTRACT FROM AUTHOR]

Aspergillus flavus is a well-known for both crops and human beings. The acquisition of resistance to azoles by A. flavus is leading to more failures occurring in the prevention of infection by A. flavus. In this study, we found that thymol, one of the major chemical constituents of the essential oil of Monarda punctate, had efficient fungicidal activity against A. flavus and led to sporular lysis. Further studies indicated that thymol treatment induced the generation of both ROS and NO in spores, whereas NO accumulation was far later than ROS accumulation in response to thymol. By blocking ROS production with the inhibitors of NADPH oxidase, NO generation was also significantly inhibited in the presence of thymol, which indicated that ROS induced NO generation in A. flavus in response to thymol treatment. Moreover, the removal of either ROS or NO attenuated lysis and death of spores exposed to thymol. The addition of SNP (exogenous NO donor) eliminated the protective effects of the inhibitors of NADPH oxidase on thymol-induced lysis and death of spores. Taken together, it could be concluded that ROS is involved in spore death induced by thymol via the induction of NO. [ABSTRACT FROM AUTHOR]

[Display omitted] • Physical field intervention shows accelerated aging of fermented products. • Ultrasonic and magnetic fields co-treatment facilitate fast aging of vinegar. • Correlation analysis between time and flavor was assessed under different treatments. Most fermented foods need a natural aging process to enrich desired flavours. This process is normally the bottleneck for cost-effective production. Therefore, it is desirable to accelerate the process and obtain products with the same flavour profile. Here, we used physical interventions (ultrasonic field, alternating magnetic field, or combination of both) to assist the aging process with naturally brewed vinegar as a case example. Flavour profiles of different physical-assisted aging process were compared with that of the naturally aged vinegar by using gas-chromatography mass-spectrometry (GC–MS) and electronic nose. Principal component analysis (PCA) and Pearson correlation analyses show that ultrasonic and alternating magnetic fields treatment could accelerate the aging process of vinegar. The highest accelerating aging effect was combination of ultrasonic and magnetic field followed by individual ultrasonic or magnetic field and natural process (combination of ultrasonic and magnetic field > ultrasonic or magnetic field individual > natural process). These results suggest that physical field intervention could potentially be used for acceleration of aging of fermented products without affecting flavour quality. [ABSTRACT FROM AUTHOR]

Aflatoxin biosynthesis has established a connection with oxidative stress, suggesting a prevention strategy for aflatoxin contamination via reactive oxygen species (ROS) removal. Epigallocatechin gallate (EGCG) is one of the most active and the richest molecules in green tea with well-known antioxidant effects. Here, we found EGCG could inhibit aflatoxin B1 (AFB1) biosynthesis without affecting mycelial growth in Aspergillus flavus, and the arrest occurred before the synthesis of toxin intermediate metabolites. Further RNA-seq analysis indicated that multiple genes involved in AFB1 biosynthesis were down-regulated. In addition, EGCG exposure facilitated the significantly decreased expression of AtfA which is a bZIP (basic leucine zipper) transcription factor mediating oxidative stress. Notably, KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis indicated that the MAPK signaling pathway target transcription factor was down-regulated by 1 mg/mL EGCG. Further Western blot analysis showed 1 mg/mL EGCG could decrease the levels of phosphorylated SakA in both the cytoplasm and nucleus. Taken together, these data evidently supported that EGCG inhibited AFB1 biosynthesis and alleviated oxidative stress via MAPK signaling pathway. Finally, we evaluated AFB1 contamination in soy sauce fermentation and found that EGCG could completely control AFB1 contamination at 8 mg/mL. Conclusively, our results supported the potential use of EGCG as a natural agent to prevent AFB1 contamination in fermentation industry. [ABSTRACT FROM AUTHOR]