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Toxins Oct 2021Food bio-preservatives are requested as substituents of chemical pesticides in food. The aim of this study was to carry out a screening of twenty biocontrol agents...
Food bio-preservatives are requested as substituents of chemical pesticides in food. The aim of this study was to carry out a screening of twenty biocontrol agents (BCAs) for their potential fungicidal activity in vitro. Twenty BCAs were tested against ten pathogenic fungi. Some of the cell-free supernatants (CFS) tested showed in vitro antifungal activity versus pathogenic fungi. The highest fungicidal activity was observed in the fermented CFS of CECT 375, CECT 493, and CECT 850, which showed a minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values of 125 and 250 g/L, respectively. The compounds responsible for the antifungal activity, such as organic and phenolic acids, were determined. Lactic acid, acetic acid, benzoic acid, and phenyllactic acid among others can be related to antifungal activity. HPLC-MS/MS analysis showed a reduction of ochratoxin A (OTA) and aflatoxin B (AFB) up to 26% ( CECT 2) and 55% ( CECT 155), respectively. The present study prompts that metabolism products of BCAs are propitious for the bioconservation of food, due to their ability to reduce the proliferation of mycotoxigenic fungi and mycotoxins production.
Topics: Aflatoxin B1; Antifungal Agents; Bacillus amyloliquefaciens; Cell-Free System; Fungicides, Industrial; In Vitro Techniques; Ochratoxins; Paenibacillus; Pantoea; Pest Control, Biological; Poisons
PubMed: 34822536
DOI: 10.3390/toxins13110752 -
Plants (Basel, Switzerland) May 2021Grapevine bunch rot, caused by and , causes important economic losses every year in grape production. In the present study, we examined the plant protective activity of...
Grapevine bunch rot, caused by and , causes important economic losses every year in grape production. In the present study, we examined the plant protective activity of the biological control agents, K165, sp. FP12 and sp. FP15 against and on grapes. The in vitro experiments showed that strain K165 significantly reduced the growth of both fungi, while FP15 restricted the growth of and FP12 was ineffective. Following the in vitro experiments, we conducted in planta experiments on grape berries. It was shown that K165, FP12 and FP15 reduced rot severity by 81%, 57% and 37%, respectively, compared to the control, whereas, in the case of , the only protective treatment was that with K165, which reduced rot by 75%. The transcriptomic analysis of the genes encoding the pathogenesis-related proteins PR2, PR3, PR4 and PR5 indicates the activation of multiple defense responses involved in the biocontrol activity of the examined biocontrol agents.
PubMed: 34068090
DOI: 10.3390/plants10050970 -
Frontiers in Plant Science 2021The sustainable development of agriculture can be stimulated by the great market availability of bio-inputs, including phosphate-solubilizing microbial strains. However,...
The sustainable development of agriculture can be stimulated by the great market availability of bio-inputs, including phosphate-solubilizing microbial strains. However, these strains are currently selected using imprecise and questionable solubilization methodologies in solid or liquid media. We hypothesized that the hydroponic system could be a more efficient methodology for selecting phosphate-solubilizing strains as plant growth promoters. This methodology was tested using the plant as a model. The growth-promoting potential of the strains was compared with that of the Biomaphos® commercial microbial mixture. The obtained calcium phosphate (CaHPO) solubilization results using the hydroponic system were inconsistent with those observed in solid and liquid media. However, the tests in liquid medium demonstrated poor performances of sp. (328EF) and (33EF) in reducing pH and solubilizing CaHPO, which corroborates with the effects of biotic stress observed in plants inoculated with these strains. Nevertheless, the hydroponic system allowed the characterization of (PA12), which is also efficient in solubilization in a liquid medium. The bacterium (PA26) was the most effective in CaHPO solubilization owing to the higher phosphorus (P) absorption, growth promotion, and physiological performance observed in plants inoculated with this bacterium. The hydroponic method proved to be superior in selecting solubilizing strains, allowing the assessment of multiple patterns, such as nutritional level, growth, photosynthetic performance, and anatomical variation in plants, and even the detection of biotic stress responses to inoculation, obtaining strains with higher growth promotion potential than Biomaphos®. This study proposed a new approach to confirm the solubilizing activity of microorganisms previously selected and potentially intended for the bio-input market that are useful in P availability for important crops, such as soybeans.
PubMed: 34777440
DOI: 10.3389/fpls.2021.759463 -
Metabolites Sep 2019Priming is a natural phenomenon that pre-conditions plants for enhanced defence against a wide range of pathogens. It represents a complementary strategy, or sustainable...
Priming is a natural phenomenon that pre-conditions plants for enhanced defence against a wide range of pathogens. It represents a complementary strategy, or sustainable alternative that can provide protection against disease. However, a comprehensive functional and mechanistic understanding of the various layers of priming events is still limited. A non-targeted metabolomics approach was used to investigate metabolic changes in plant growth-promoting rhizobacteria (PGPR)-primed seedlings infected with the anthracnose-causing fungal pathogen, , with a focus on the post-challenge primed state phase. At the 4-leaf growth stage, the plants were treated with a strain of at 10 cfu mL. Following a 24 h PGPR application, the plants were inoculated with a spore suspension (10 spores mL), and the infection monitored over time: 1, 3, 5, 7 and 9 days post-inoculation. Non-infected plants served as negative controls. Intracellular metabolites from both inoculated and non-inoculated plants were extracted with 80% methanol-water. The extracts were chromatographically and spectrometrically analysed on an ultra-high performance liquid chromatography (UHPLC) system coupled to high-definition mass spectrometry. The acquired multidimensional data were processed to create data matrices for chemometric modelling. The computed models indicated time-related metabolic perturbations that reflect primed responses to the fungal infection. Evaluation of orthogonal projection to latent structure-discriminant analysis (OPLS-DA) loading shared and unique structures (SUS)-plots uncovered the differential stronger defence responses against the fungal infection observed in primed plants. These involved enhanced levels of amino acids (tyrosine, tryptophan), phytohormones (jasmonic acid and salicylic acid conjugates, and zeatin), and defence-related components of the lipidome. Furthermore, other defence responses in both naïve and primed plants were characterised by a complex mobilisation of phenolic compounds and biosynthesis of the flavones, apigenin and luteolin and the 3-deoxyanthocyanidin phytoalexins, apigeninidin and luteolinidin, as well as some related conjugates.
PubMed: 31547091
DOI: 10.3390/metabo9100194 -
Applied and Environmental Microbiology Jul 2019Recent papers have reported dipeptides containing d-amino acids to have novel effects that cannot be observed with ll-dipeptides, and such dipeptides are expected to be...
Recent papers have reported dipeptides containing d-amino acids to have novel effects that cannot be observed with ll-dipeptides, and such dipeptides are expected to be novel functional compounds for pharmaceuticals and food additives. Although the functions of d-amino acid-containing dipeptides are gaining more attention, there are few reports on the synthetic enzymes that can accept d-amino acids as substrates, and synthetic methods for d-amino acid-containing dipeptides have not yet been constructed. Previously, we developed a chemoenzymatic system for amide synthesis that comprised enzymatic activation and a subsequent nucleophilic substitution reaction. In this study, we demonstrated the application of the system for d-amino acid-containing-dipeptide synthesis. We chose six adenylation domains as targets according to our newly constructed hypothesis, i.e., an adenylation domain located upstream from the epimerization domain may activate d-amino acid as well as l-amino acid. We successfully synthesized over 40 kinds of d-amino acid-containing dipeptides, including ld-, dl-, and dd-dipeptides, using only two adenylation domains, TycA-A from tyrocidine synthetase and BacB2-A from bacitracin synthetase. Furthermore, this study offered the possibility that the epimerization domain could be a clue to the activity of the adenylation domains toward d-amino acid. This paper provides additional information regarding d-amino acid-containing-dipeptide synthesis through the combination of enzymatic adenylation and chemical nucleophilic reaction, and this system will be a useful tool for dipeptide synthesis. Because almost all amino acids in nature are l-amino acids, the functioning of d-amino acids has received little attention. Thus, there is little information available on the activity of enzymes toward d-amino acids or synthetic methods for d-amino acid-containing dipeptides. Recently, d-amino acids and d-amino acid-containing peptides have attracted attention as novel functional compounds, and d-amino acid-activating enzymes and synthetic methods are required for the development of the d-amino acid-containing-peptide industry. This study provides additional knowledge regarding d-amino acid-activating enzymes and proposes a unique synthetic method for d-amino acid-containing peptides, including ld-, dl-, and dd-dipeptides.
Topics: Amino Acids; Bacillus licheniformis; Bacterial Proteins; Biocatalysis; Dipeptides; Paenibacillus; Peptide Synthases; Protein Domains; Substrate Specificity
PubMed: 31003981
DOI: 10.1128/AEM.00120-19 -
Advanced Science (Weinheim,... Feb 2024Post-translational prenylations, found in eukaryotic primary metabolites and bacterial secondary metabolites, play crucial roles in biomolecular interactions. Employing...
Post-translational prenylations, found in eukaryotic primary metabolites and bacterial secondary metabolites, play crucial roles in biomolecular interactions. Employing genome mining methods combined with AlphaFold2-based predictions of protein interactions, PalQ , a prenyltransferase responsible for the tryptophan prenylation of RiPPs produced by Paenibacillus alvei, is identified. PalQ differs from cyanobactin prenyltransferases because of its evolutionary relationship to isoprene synthases, which enables PalQ to transfer extended prenyl chains to the indole C3 position. This prenylation introduces structural diversity to the tryptophan side chain and also leads to conformational dynamics in the peptide backbone, attributed to the cis/trans isomerization that arises from the formation of a pyrrolidine ring. Additionally, PalQ exhibited pronounced positional selectivity for the C-terminal tryptophan. Such enzymatic characteristics offer a toolkit for peptide therapeutic lipidation.
Topics: Dimethylallyltranstransferase; Tryptophan; Prenylation; Protein Processing, Post-Translational; Peptides
PubMed: 38059776
DOI: 10.1002/advs.202307372 -
Open Life Sciences 2020[This corrects the article DOI: 10.1515/biol-2020-0019.].
[This corrects the article DOI: 10.1515/biol-2020-0019.].
PubMed: 33818580
DOI: 10.1515/biol-2020-0104 -
Microorganisms Aug 2023Honey bees coexist with fungi that colonize hive surfaces and pollen. Some of these fungi are opportunistic pathogens, but many are beneficial species that produce...
Honey bees coexist with fungi that colonize hive surfaces and pollen. Some of these fungi are opportunistic pathogens, but many are beneficial species that produce antimicrobial compounds for pollen conservation and the regulation of pathogen populations. In this study, we tested the in vitro antimicrobial activity of strains isolated from bee bread against (associated with European foulbrood disease) and three species that cause stonebrood disease. We found that methanol extracts of strains B18 and B195 inhibited the growth of at a concentration of 0.39 mg/mL. Bioactivity-guided dereplication revealed that the activity of the crude extracts correlated with the presence of diketopiperazines, a siderophore, and three unknown compounds. We propose that non-pathogenic fungi such as spp. and their metabolites in bee bread could be an important requirement to prevent disease. Agricultural practices involving the use of fungicides can disrupt the fungal community and thus negatively affect the health of bee colonies.
PubMed: 37630627
DOI: 10.3390/microorganisms11082067 -
Virulence Dec 2020is a bacterial pathogen that causes epidemic outbreaks of European foulbrood (EFB) in honey bee populations. The pathogenicity of a bacterium depends on its virulence,...
is a bacterial pathogen that causes epidemic outbreaks of European foulbrood (EFB) in honey bee populations. The pathogenicity of a bacterium depends on its virulence, and understanding the mechanisms influencing virulence may allow for improved disease control and containment. Using a standardized assay, we demonstrate that virulence varies greatly among sixteen isolates from five European countries. Additionally, we explore the causes of this variation. In this study, virulence was independent of the multilocus sequence type of the tested pathogen, and was not affected by experimental co-infection with , a bacterium often associated with EFB outbreaks. Virulence was correlated with the growth dynamics of isolates in artificial medium, and with the presence of a plasmid carrying a gene coding for the putative toxin melissotoxin A. Our results suggest that some strains showed an increased virulence due to the acquisition of a toxin-carrying mobile genetic element. We discuss whether strains with increased virulence play a role in recent EFB outbreaks.
Topics: Animals; Bacterial Toxins; Bacterial Typing Techniques; Bees; Enterococcaceae; Gram-Positive Bacterial Infections; Interspersed Repetitive Sequences; Larva; Multilocus Sequence Typing; Plasmids; Virulence
PubMed: 32456539
DOI: 10.1080/21505594.2020.1768338 -
Metabolites May 2020Plant growth-promoting rhizobacteria (PGPR) are beneficial microbes in the rhizosphere that can directly or indirectly stimulate plant growth. In addition, some can...
Plant growth-promoting rhizobacteria (PGPR) are beneficial microbes in the rhizosphere that can directly or indirectly stimulate plant growth. In addition, some can prime plants for enhanced defense against a broad range of pathogens and insect herbivores. In this study, four PGPR strains ( N04, N19, T19, and T22) were used to induce priming in (cv. Moneymaker) plants. Plants were inoculated with each of the four PGPRs, and plant tissues (roots, stems, and leaves) were harvested at 24 h and 48 h post-inoculation. Methanol-extracted metabolites were analyzed by ultra-high performance liquid chromatography mass spectrometry (UHPLC-MS). Chemometric methods were applied to mine the data and characterize the differential metabolic profiles induced by the PGPR. The results revealed that all four strains induced defense-related metabolic reprogramming in the plants, characterized by dynamic changes to the metabolomes involving hydroxycinnamates, benzoates, flavonoids, and glycoalkaloids. In addition, targeted analysis of aromatic amino acids indicated differential quantitative increases or decreases over a two-day period in response to the four PGPR strains. The metabolic alterations point to an altered or preconditioned state that renders the plants primed for enhanced defense responses. The results contribute to ongoing efforts in investigating and unraveling the biochemical processes that define the PGPR priming phenomenon.
PubMed: 32443694
DOI: 10.3390/metabo10050210