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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 -
Antibiotics (Basel, Switzerland) Jun 2024We evaluated the activities of aztreonam/avibactam and recently approved β-lactamase inhibitor combinations (BLICs) to compare the antimicrobial susceptibility patterns...
Activity of Aztreonam/Avibactam and Recently Approved β-Lactamase Inhibitor Combinations against Enterobacterales and from Intensive Care Unit and Non-Intensive Care Unit Patients.
We evaluated the activities of aztreonam/avibactam and recently approved β-lactamase inhibitor combinations (BLICs) to compare the antimicrobial susceptibility patterns of Enterobacterales and isolated from intensive care unit (ICU) and non-ICU patients. Clinical isolates (1/patient) were consecutively collected from 72 United States medical centres in 2020-2022 and susceptibility tested by broth microdilution. The results for 5421 isolates from ICU patients were analysed and compared to those for 20,649 isolates from non-ICU patients. Isolates from ventilator-associated pneumonia patients were analysed separately. Aztreonam/avibactam inhibited 100.0%/>99.9% Enterobacterales and 100.0%/98.3% of carbapenem-resistant Enterobacterales (CRE) from ICU/non-ICU patients at ≤8 mg/L, respectively. The CRE susceptibility rates were 88.5%/82.9% for ceftazidime/avibactam, 82.1%/81.2% for meropenem/vaborbactam, and 78.2%/72.6% for imipenem/relebactam among ICU/non-ICU isolates. Among the isolates from ICU/non-ICU patients, the susceptibility rates were 96.3%/97.6% for ceftazidime/avibactam, 97.2/98.4% for ceftolozane/tazobactam, 97.1%/98.0% for imipenem/relebactam, 77.8%/84.6% for piperacillin/tazobactam, and 76.9%/85.8% for meropenem; aztreonam/avibactam inhibited 78.0%/81.9% of at ≤8 mg/L. In summary, lower susceptibility rates were observed among ICU than non-ICU isolates. Aztreonam/avibactam exhibited potent in vitro activity and broad-spectrum activity against Enterobacterales from ICU and non-ICU patients, including CRE and isolates non-susceptible to newer BLICs. Against , aztreonam/avibactam showed a spectrum of activity comparable to that of piperacillin/tazobactam, meropenem, and ceftazidime.
PubMed: 38927230
DOI: 10.3390/antibiotics13060564 -
Antibiotics (Basel, Switzerland) Jun 2024Carbapenemases, a class of enzymes specialized in the hydrolysis of carbapenems, represent a significant threat to global public health. These enzymes are classified... (Review)
Review
Carbapenemases, a class of enzymes specialized in the hydrolysis of carbapenems, represent a significant threat to global public health. These enzymes are classified into different Ambler's classes based on their active sites, categorized into classes A, D, and B. Among the most prevalent types are IMI/NMC-A, KPC, VIM, IMP, and OXA-48, commonly associated with pathogenic species such as , , and . The emergence and dissemination of carbapenemase-producing bacteria have raised substantial concerns due to their ability to infect humans and animals (both companion and food-producing) and their presence in environmental reservoirs. Adopting a holistic One Health approach, concerted efforts have been directed toward devising comprehensive strategies to mitigate the impact of antimicrobial resistance dissemination. This entails collaborative interventions, highlighting proactive measures by global organizations like the World Health Organization, the Center for Disease Control and Prevention, and the Food and Agriculture Organization. By synthesizing the evolving landscape of carbapenemase epidemiology in Portugal and tracing the trajectory from initial isolated cases to contemporary reports, this review highlights key factors driving antibiotic resistance, such as antimicrobial use and healthcare practices, and underscores the imperative for sustained vigilance, interdisciplinary collaboration, and innovative interventions to curb the escalating threat posed by antibiotic-resistant pathogens. Finally, it discusses potential alternatives and innovations aimed at tackling carbapenemase-mediated antibiotic resistance, including new therapies, enhanced surveillance, and public awareness campaigns.
PubMed: 38927223
DOI: 10.3390/antibiotics13060557 -
Antibiotics (Basel, Switzerland) Jun 2024The Infectious Diseases Society of America (IDSA) recommends a single dose of an aminoglycoside for uncomplicated cystitis caused by extended-spectrum beta-lactamase...
The Infectious Diseases Society of America (IDSA) recommends a single dose of an aminoglycoside for uncomplicated cystitis caused by extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales (ESBL-E) and difficult-to-treat . However, there is very little recent clinical evidence to support this recommendation. The objective of this study was to evaluate the safety and efficacy of a single-dose aminoglycoside for cystitis caused by ESBL-E or . This was a multicenter, retrospective, cohort study. Patients who received ≥3 days of standard of care were compared to patients who received a one-time dose of an aminoglycoside with or without a short course of effective therapy before. The primary outcome was the rate of relapse defined as requiring escalation of antibiotics or starting new antibiotic therapy within 14 days after the completion of antibiotics. A total of 66 patients were included in this study, with 33 patients in each arm. There were more males and complicated cystitis patients in the standard-of-care group. There was no difference found in the rate of relapse. The length of stay was significantly shorter in the aminoglycoside group (4.5 ± 4.4 days vs. 14.1 ± 10.1 days, < 0.0001). A one-time dose of an aminoglycoside did not increase the risk of relapse and was associated with a shorter length of stay when used to treat cystitis caused by ESBL-E or .
PubMed: 38927218
DOI: 10.3390/antibiotics13060552 -
Antibiotics (Basel, Switzerland) Jun 2024Colistin is a last-resort antimicrobial for treating multidrug-resistant Gram-negative bacteria. Phenotypic colistin resistance is highly associated with...
Colistin is a last-resort antimicrobial for treating multidrug-resistant Gram-negative bacteria. Phenotypic colistin resistance is highly associated with plasmid-mediated mobile colistin resistance () genes. -bearing have been detected in many countries, with the emergence of colistin-resistant pathogens a global concern. This study assessed the distribution of , , , , and genes with phenotypic colistin resistance in isolates from diarrheal infants and children in Bangladesh. Bacteria were identified using the API-20E biochemical panel and 16s rDNA gene sequencing. Polymerase chain reactions detected gene variants in the isolates. Their susceptibilities to colistin were determined by agar dilution and E-test by minimal inhibitory concentration (MIC) measurements. Over 31.6% (71/225) of isolates showed colistin resistance according to agar dilution assessment (MIC > 2 μg/mL). Overall, 15.5% of isolates carried genes (7, ; 17, ; 13, and , with co-occurrence occurring in two isolates). Clinical breakout MIC values (≥4 μg/mL) were associated with 91.3% of -positive isolates. The -positive pathogens included twenty spp., five , five spp., two , and three . The -genes appeared to be significantly associated with phenotypic colistin resistance phenomena ( = 0.000), with 100% colistin-resistant isolates showing MDR phenomena. The age and sex of patients showed no significant association with detected variants. Overall, -associated colistin-resistant bacteria have emerged in Bangladesh, which warrants further research to determine their spread and instigate activities to reduce resistance.
PubMed: 38927200
DOI: 10.3390/antibiotics13060534 -
Antibiotics (Basel, Switzerland) Jun 2024The prevalence of carbapenem-resistant has dramatically increased over the last decade, and antibiotics alone are not enough to eradicate infections caused by this...
The prevalence of carbapenem-resistant has dramatically increased over the last decade, and antibiotics alone are not enough to eradicate infections caused by this opportunistic pathogen. Phage therapy is a fresh treatment that can be administered under compassionate use, particularly against chronic cases. However, it is necessary to thoroughly characterize the virus before therapeutic application. Our work describes the discovery of the novel sequenced bacteriophage, vB_PaeP-F1Pa, containing an integrase, performs a phylogenetical analysis, describes its stability at a physiological pH and temperature, latent period (40 min), and burst size (394 ± 166 particles per bacterial cell), and demonstrates its ability to infect MDR and XDR strains. Moreover, this novel bacteriophage was able to inhibit the growth of bacteria inside preformed biofilms. The present study offers a road map to analyze essential areas for successful phage therapy against MDR and XDR infections, and shows that a phage containing an integrase is also able to show good in vitro results, indicating that it is very important to perform a genomic analysis before any clinical use, in order to prevent adverse effects in patients.
PubMed: 38927189
DOI: 10.3390/antibiotics13060523