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Antioxidants (Basel, Switzerland) Jun 2024This study explored, for the first time, the chemical composition and in vitro antioxidant and antibacterial activities of a caper leaf essential oil (EO) emulsion for...
This study explored, for the first time, the chemical composition and in vitro antioxidant and antibacterial activities of a caper leaf essential oil (EO) emulsion for possible food applications as a natural preservative. The EO was extracted by hydrodistillation from the leaves of growing wild in the Aeolian Archipelago (Sicily, Italy) and exhibited a pungent, sulphurous odour. The volatile fraction of the emulsion, analysed by SPME-GC-MS, consisted of over 100 compounds and was dominated by compounds with recognised antibacterial and antioxidant properties, namely dimethyl tetrasulfide (18.41%), dimethyl trisulfide (12.58%), methyl isothiocyanate (7.97%), and terpinen-4-ol (6.76%). The emulsion was effective against all bacterial strains tested (, , , subsp. enterica serovar Enteritidis, ), with exhibiting the lowest minimum inhibitory concentration (MIC = 0.02 mg/mL) while had the highest (MIC = 0.06 mg/mL). The emulsion had a good DPPH (2,2-diphenyl-1-picrylhydrazine) radical scavenging activity that was dose-dependent and equal to 42.98% at the 0.08 mg/mL level with an IC value of 0.099 mg/mL. Based on the results, the caper leaf EO emulsion has the potential to be proposed as a natural alternative to chemical preservatives in the food industry.
PubMed: 38929157
DOI: 10.3390/antiox13060718 -
Antioxidants (Basel, Switzerland) May 2024() is an opportunistic pathogen frequently isolated from cutaneous chronic wounds. How , in the presence of oxidative stress (OS), colonizes chronic wounds and forms a...
() is an opportunistic pathogen frequently isolated from cutaneous chronic wounds. How , in the presence of oxidative stress (OS), colonizes chronic wounds and forms a biofilm is still unknown. The purpose of this study is to investigate the changes in gene expression seen when PA is challenged with the high levels of OS present in chronic wounds. We used a biofilm-forming strain isolated from the chronic wounds of our murine model (RPA) and performed a qPCR to obtain gene expression patterns as RPA developed a biofilm in vitro in the presence of high levels of OS, and then compared the findings in vivo, in our mouse model of chronic wounds. We found that the planktonic bacteria under OS conditions overexpressed quorum sensing genes that are important for the bacteria to communicate with each other, antioxidant stress genes important to reduce OS in the microenvironment for survival, biofilm formation genes and virulence genes. Additionally, we performed RNAseq in vivo and identified the activation of novel genes/pathways of the Type VI Secretion System (T6SS) involved in RPA pathogenicity. In conclusion, RPA appears to survive the high OS microenvironment in chronic wounds and colonizes these wounds by turning on virulence, biofilm-forming and survival genes. These findings reveal pathways that may be promising targets for new therapies aimed at disrupting -containing biofilms immediately after debridement to facilitate the treatment of chronic human wounds.
PubMed: 38929094
DOI: 10.3390/antiox13060655 -
International Journal of Environmental... May 2024The effects of exposure to airborne particulate matter with a size of 10 μm or less (PM) on C57BL/6 mouse corneas, their response to (PA) infection, and the protective...
The effects of exposure to airborne particulate matter with a size of 10 μm or less (PM) on C57BL/6 mouse corneas, their response to (PA) infection, and the protective effects of SKQ1 were determined. C57BL/6 mouse corneas receiving PBS or SKQ1 were exposed to control (air) or PM for 2 weeks, infected, and the disease was documented by clinical score, PMN quantitation, bacterial plate count, RT-PCR and Western blot. PBS-treated, PM-exposed corneas did not differ at 1 day postinfection (dpi), but exhibited earlier (3 dpi) corneal thinning compared to controls. By 3 dpi, PM significantly increased corneal mRNA levels of several pro-inflammatory cytokines, but decreased IL-10, NQO1, GR1, GPX4, and Nrf2 over control. SKQ1 reversed these effects and Western blot selectively confirmed the RT-PCR results. PM resulted in higher viable bacterial plate counts at 1 and 3 dpi, but SKQ1 reduced them at 3 dpi. PM significantly increased MPO in the cornea at 3 dpi and was reduced by SKQ1. SKQ1, used as an adjunctive treatment to moxifloxacin, was not significantly different from moxifloxacin alone. Exposure to PM increased the susceptibility of C57BL/6 to PA infection; SKQ1 significantly reversed these effects, but was not effective as an adjunctive treatment.
Topics: Animals; Mice, Inbred C57BL; Pseudomonas Infections; Particulate Matter; Pseudomonas aeruginosa; Mice; Cornea; Disease Susceptibility; Cytokines; Female; Air Pollutants
PubMed: 38928968
DOI: 10.3390/ijerph21060722 -
International Journal of Molecular... Jun 2024This paper presents the work performed to transition a lab-scale synthesis (1 g) to a large-scale (400 g) synthesis of the 3-5-diamino-1H-Pyrazole Disperazol, a new...
This paper presents the work performed to transition a lab-scale synthesis (1 g) to a large-scale (400 g) synthesis of the 3-5-diamino-1H-Pyrazole Disperazol, a new pharmaceutical for treatment of antibiotic-resistant biofilm infections. The potentially hazardous diazotisation step in the lab-scale synthesis was transformed to a safe and easy-to-handle flow chemistry step. Additionally, the paper presents an OSHA-recommended safety assessment of active compound , as performed by Fauske and Associates, LLC, Burr Ridge, IL, USA.
Topics: Pyrazoles; Pseudomonas aeruginosa; Anti-Bacterial Agents; Biofilms; Humans; Pseudomonas Infections; Risk Assessment
PubMed: 38928443
DOI: 10.3390/ijms25126737 -
International Journal of Molecular... Jun 2024An approach based on the heat stress and microbial stress model of the medicinal plant was proposed to elucidate the regulation and mechanism of bioactive phenol...
An approach based on the heat stress and microbial stress model of the medicinal plant was proposed to elucidate the regulation and mechanism of bioactive phenol accumulation. This method integrates LC-MS/MS analysis, 16S rRNA sequencing, RT-qPCR, and molecular assays to investigate the regulation of phenolic metabolite biosynthesis in rhizome (SL) under stress. Previous research has shown that the metabolites and genes involved in phenol biosynthesis correlate to the upregulation of genes involved in plant-pathogen interactions. High-temperature and the presence of bacteria were observed alongside SL growth. Under conditions of heat stress or bacteria stress, both the metabolites and genes involved in phenol biosynthesis were upregulated. The regulation of phenol content and phenol biosynthesis gene expression suggests that phenol-based chemical defense of SL is stimulated under stress. Furthermore, the rapid accumulation of phenolic substances relied on the consumption of amino acids. Three defensive proteins, namely Ss4CL, SsC4H, and SsF3'5'H, were identified and verified to elucidate phenol biosynthesis in SL. Overall, this study enhances our understanding of the phenol-based chemical defense of SL, indicating that bioactive phenol substances result from SL's responses to the environment and providing new insights for growing the high-phenol-content medicinal herb SL.
Topics: Plants, Medicinal; Heat-Shock Response; Gene Expression Regulation, Plant; Phenols; Phenol; Plant Proteins; Rhizome; Pseudomonas; Tandem Mass Spectrometry; RNA, Ribosomal, 16S
PubMed: 38928085
DOI: 10.3390/ijms25126379 -
International Journal of Molecular... Jun 2024Various metabolites, including phytohormones, phytoalexins, and amino acids, take part in the plant immune system. Herein, we analyzed the effects of L-methionine (Met),...
Various metabolites, including phytohormones, phytoalexins, and amino acids, take part in the plant immune system. Herein, we analyzed the effects of L-methionine (Met), a sulfur-containing amino acid, on the plant immune system in tomato. Treatment with low concentrations of Met enhanced the resistance of tomato to a broad range of diseases caused by the hemi-biotrophic bacterial pathogen pv. ) and the necrotrophic fungal pathogen (), although it did not induce the production of any antimicrobial substances against these pathogens in tomato leaf tissues. Analyses of gene expression and phytohormone accumulation indicated that Met treatment alone did not activate the defense signals mediated by salicylic acid, jasmonic acid, and ethylene. However, the salicylic acid-responsive defense gene and the jasmonic acid-responsive gene were induced more rapidly in Met-treated plants after infection with and , respectively. These findings suggest that low concentrations of Met have a priming effect on the phytohormone-mediated immune system in tomato.
Topics: Solanum lycopersicum; Methionine; Gene Expression Regulation, Plant; Plant Diseases; Botrytis; Pseudomonas syringae; Cyclopentanes; Plant Growth Regulators; Oxylipins; Plant Immunity; Disease Resistance; Salicylic Acid; Plant Leaves; Plant Proteins; Ethylenes
PubMed: 38928022
DOI: 10.3390/ijms25126315 -
Genes Jun 2024Many enzymes in the Raetz pathway for lipid A biosynthesis in are essential. A homologous protein Pa1792|LpxH in is known to complement the loss of LpxH in ....
Many enzymes in the Raetz pathway for lipid A biosynthesis in are essential. A homologous protein Pa1792|LpxH in is known to complement the loss of LpxH in . Genome-wide transposon-insertion sequencing analysis indicates that is essential in . However, genetic analysis of in has not been carried out, partly because the conditional alleles of essential genes are not readily constructed. In this study, we first constructed a plasmid-based temperature-sensitive mutant or in PAO1. Spot-plating assay indicated that was lethal at a restrictive temperature, confirming its essentiality for growth. Microscopic analysis revealed that exhibited an oval-shaped morphology, suggesting that was required for rod-shape formation. SDS-PAGE and Western blotting analysis showed that failed to synthesize lipid A, consistent with its function in lipid A biosynthesis. Strong expression of but not the non-homologous isoenzyme or impeded growth and caused cell lysis, implying that -specific cofactors were required for this toxic effect in . Together, our results demonstrate that is essential for lipid A biosynthesis, rod-shaped growth, and viability in . We propose that this plasmid-based conditional allele is a useful tool for the genetic study of essential genes in .
Topics: Pseudomonas aeruginosa; Plasmids; Bacterial Proteins; Temperature; Mutation; Lipid A; Escherichia coli
PubMed: 38927720
DOI: 10.3390/genes15060784 -
Biology Jun 2024KT2440 is a popular platform for bioremediation due to its robust tolerance to environmental stress and strong biodegradation capacity. Limited research on the salt...
KT2440 is a popular platform for bioremediation due to its robust tolerance to environmental stress and strong biodegradation capacity. Limited research on the salt tolerance of KT2440 has hindered its application. In this study, the strain KT2440 was tested to tolerate a maximum of 4% / NaCl cultured with minimal salts medium. Transcriptomic data in a high-salinity environment showed significant expression changes in genes in membrane components, redox processes, chemotaxis, and cellular catabolic processes. -encoding betaine-aldehyde dehydrogenase was identified from the transcriptome data to overexpress and enhance growth profile of the strain KT2440 in minimal salts medium containing 4% / NaCl. Meanwhile, screening for exogenous salt-tolerant genes revealed that the Na/H antiporter from significantly increased the growth of the strain KT2440 in 4% / NaCl. Then, co-expression of and (KT2440-) increased the maximum salt tolerance of strain KT2440 to 5% / NaCl. Further addition of betaine and proline improved the salt tolerance of the engineered strain to 6% / NaCl. Finally, the engineered strain KT2440- was able to degrade 56.70% of benzoic acid and 95.64% of protocatechuic acid in minimal salt medium containing 4% / NaCl in 48 h, while no biodegradation was observed in the normal strain KT2440 in the same conditions. However, the strain KT2440- failed to degrade catechol in minimal salt medium containing 3% / NaCl. This study illustrated the improvement in the salt tolerance performance of KT2440 and the feasibility of engineered strain KT2440 as a potential salt-tolerant bioremediation platform.
PubMed: 38927284
DOI: 10.3390/biology13060404 -
Biology May 2024Compared to pathogens and , HYS has stronger virulence towards . However, the underlying mechanisms haven't been fully understood. The heme synthesis system is...
Compared to pathogens and , HYS has stronger virulence towards . However, the underlying mechanisms haven't been fully understood. The heme synthesis system is essential for virulence, and former studies of HemN have focused on the synthesis of heme, while the relationship between HemN and virulence were barely pursued. In this study, we hypothesized that deficiency affected 7-hydroxytropolone (7-HT) biosynthesis and redox levels, thereby reducing bacterial virulence. There are four genes in HYS, and we reported for the first time that deletion of significantly reduced the virulence of HYS towards , whereas the reduction in virulence by the other three genes was not significant. Interestingly, deletion significantly reduced colonization of HYS in the gut of . Further studies showed that HemN2 was regulated by GacS and participated in the virulence of HYS towards by mediating the synthesis of the virulence factor 7-HT. In addition, HemN2 and GacS regulated the virulence of HYS by affecting antioxidant capacity and nitrative stress. In short, the findings that HemN2 was regulated by the Gac system and that it was involved in bacterial virulence via regulating 7-HT synthesis and redox levels were reported for the first time. These insights may enlighten further understanding of HemN-based virulence in the genus .
PubMed: 38927253
DOI: 10.3390/biology13060373 -
Biology May 2024Tomato bacterial spots, caused by pv. () and (), as well as bacterial specks, caused by two strains of pv. ( and ), represent significant threats to tomato...
Tomato bacterial spots, caused by pv. () and (), as well as bacterial specks, caused by two strains of pv. ( and ), represent significant threats to tomato production in the El-Sharkia governorate, often resulting in substantial yield losses. The objective of this study was to evaluate the efficacy of various biocontrol culture filtrates, including bacteria and fungi agents, in managing the occurrence and severity of these diseases, while also monitoring physiological changes in tomato leaves, including antioxidant enzymes, phenolics, and pigment content. The culture filtrates from examined species (, and ), as well as the tested bacteria (, , and ) at concentrations of 25%, 50%, and 100%, significantly inhibited the proliferation of pathogenic bacteria In vitro. For the In vivo experiments, we used specific doses of 5 mL of spore suspension per plant for the fungal bioagents at a concentration of 2.5 × 10 spores/mL. The bacterial bioagents were applied as a 10 mL suspension per plant at a concentration of 1 × 10 CFU/mL. Spraying the culture filtrates of the tested bioagents two days before infection In vivo significantly reduced disease incidence and severity. exhibited the highest efficacy among the fungal bioagents, followed by and . Meanwhile, the culture filtrate of emerged as the most potent among the bacterial bioagents, followed by . Furthermore, applying these culture filtrates resulted in elevated levels of chitinase, peroxidase, and polyphenol oxidase activity. This effect extended to increased phenol contents, as well as chlorophyll a, chlorophyll b, and carotenoids in sprayed tomato plants compared to the control treatment. Overall, these findings underscore the potential of these biocontrol strategies to effectively mitigate disease incidence and severity while enhancing plant defense mechanisms and physiological parameters, thus offering promising avenues for sustainable disease management in tomato production.
PubMed: 38927249
DOI: 10.3390/biology13060369