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International Journal of Systematic and... Apr 2024By investigating wet and dry age-related ripening of beef, strains V3/3/4/13 and V3/K/3/5 were isolated. Strain V3/3/4/13 exhibited more than 99 % 16S rRNA gene-based...
By investigating wet and dry age-related ripening of beef, strains V3/3/4/13 and V3/K/3/5 were isolated. Strain V3/3/4/13 exhibited more than 99 % 16S rRNA gene-based similarity to and other members of this group, while isolate V3/K/3/5 was very close to and a number of relatives within the group. Additional comparisons of complete sequences and draft genomes allowed us to place isolate V3/3/4/13 close to DSM 26521. In the case of V3/K/3/5 the closest relative was DSM 11331. Average nucleotide identity (ANIb) and digital DNA-DNA hybridization (dDDH) values calculated from the draft genomes of V3/3/4/13 and DSM 26521 were 88.5 and 39.8 %, respectively. For V3/K/3/5 and its closest relative DSM 11331, the ANIb value was 95.1 % and the dDDH value was 60.7 %. The DNA G+C contents of V3/3/4/13 and V3/K/3/5 were 57.4 and 60.8 mol%, respectively. Predominant fatty acids were C, C ω7, C cyclo and summed feature C ω7/C iso 2OH. The main respiratory quinones were Q9, with minor proportions of Q8 and, in the case of V3/K/3/5, additional Q10. The main polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and, in the case of V3/K/3/5, additional phosphatidylcholine. Based on the combined data, isolates V3/3/4/13 and V3/K/3/5 should be considered as representatives of two novel species. The type strain of the newly proposed sp. nov. is V3/3/4/13 (=DSM 113654=LMG 32520), a second strain belonging to the same species is FLM 004-28 (=DSM 113604=LMG 32521); the type strain for the newly proposed sp. nov. is V3/K/3/5 (=DSM 113573=LMG 32518) with a second isolate FLM 11 (=DSM 113572=LMG 32519).
Topics: Animals; Cattle; Base Composition; Chickens; Fatty Acids; RNA, Ribosomal, 16S; Phylogeny; Sequence Analysis, DNA; DNA, Bacterial; Bacterial Typing Techniques; Pseudomonas; Nucleotides
PubMed: 38587505
DOI: 10.1099/ijsem.0.006293 -
Frontiers in Microbiology 2023CFBP2392 has been recognized as a potential biocontrol agent due to its ability to suppress damping-off and root rot disease. This isolate has antibacterial activity...
CFBP2392 has been recognized as a potential biocontrol agent due to its ability to suppress damping-off and root rot disease. This isolate has antibacterial activity as many other strains from the complex. In this work, the antibacterial and antifungal activity of the strain were explored. Dual culture assays evidenced the antifungal activity of the strain against different phytopathogens: sp., , , and . Purification of an antifungal fraction was performed by preparative HPLC from the chemical extraction of growth media. The fraction showed altered growth and ultrastructure. Transmission electron microscopy revealed the purified compound hypertrophied mitochondria, membranous vesicles, and a higher number of vacuoles in cytoplasm. In addition, co-cultivation of CFBP2392 with resulted in an enlarged and deformed cell wall. To gain genomic insights on this inhibition, the complete genome of CFBP2392 was obtained with Oxford Nanopore technology. Different biosynthetic gene clusters (BGCs) involved in specialized metabolites production including a lokisin-like and a koreenceine-like cluster were identified. In accordance with the putative BGCs identified, sequence phylogeny analysis of the MacB transporter in the lokisin-like cluster further supports the similarity with other transporters from the amphisin family. Our results give insights into the cellular effects of the purified microbial metabolite in ultrastructure and provide a genomic background to further explore the specialized metabolite potential.
PubMed: 38033591
DOI: 10.3389/fmicb.2023.1286926 -
Journal of Microbiological Methods Sep 2023Salmonella is one of the most important foodborne pathogens and its analysis in raw and processed products is mandatory in the food industry. Although microbiological...
Salmonella is one of the most important foodborne pathogens and its analysis in raw and processed products is mandatory in the food industry. Although microbiological analysis is the standard practice for Salmonella determination, these assays are commonly laborious and time-consuming, thus, alternative techniques based on easy operation, few manipulation steps, low cost, and reduced time are desirable. In this paper, we demonstrate the use of an e-nose based on ionogel composites (ionic liquid + gelatine + FeO particles) as a complementary tool for the conventional microbiological detection of Salmonella. We used the proposed methodology for differentiating Salmonella from Escherichia coli, Pseudomonas fluorescens, Pseudomonas aeruginosa, and Staphylococcus aureus in nonselective medium: pre-enrichment in brain heart infusion (BHI) (incubation at 35 °C, 24 h) and enrichment in tryptone soy agar (TSA) (incubation at 35 °C, 24 h), whereas Salmonella differentiation from E. coli and P. fluorescens was also evaluated in selective media, bismuth sulfite agar (BSA), xylose lysine deoxycholate agar (XLD), and brilliant green agar (BGA) (incubation at 35 °C, 24 h). The obtained data were compared by principal component analysis (PCA) and different machine learning algorithms: multilayer perceptron (MLP), linear discriminant analysis (LDA), instance-based (IBk), and Logistic Model Trees (LMT). For the nonselective media, under optimized conditions, taking merged data of BHI + TSA (total incubation time of 48 h), an accuracy of 85% was obtained with MLP, LDA, and LMT, while five separated clusters were presented in PCA, each cluster corresponding to a bacterium. In addition, for evaluation of the e-nose for discrimination of Salmonella using selective media, considering the combination of BSA + XLD and total incubation of 72 h, the PCA showed three separated and well-defined clusters corresponding to Salmonella, E. coli, and P. fluorescens, and an accuracy of 100% was obtained for all classifiers.
Topics: Agar; Electronic Nose; Escherichia coli; Salmonella; Culture Media; Food Microbiology
PubMed: 37558057
DOI: 10.1016/j.mimet.2023.106805 -
Frontiers in Microbiology 2023Bacterial communication is a fundamental process used to synchronize gene expression and collective behavior among the bacterial population. The most studied bacterial...
Bacterial communication is a fundamental process used to synchronize gene expression and collective behavior among the bacterial population. The most studied bacterial communication system is quorum sensing, a cell density system, in which the concentration of inductors increases to a threshold level allowing detection by specific receptors. As a result, bacteria can change their behavior in a coordinated way. While in quorum sensing based on the synthesis of -acyl homoserine lactone molecules is well studied, volatile organic compounds, although considered to be communication signals in the rhizosphere, are understudied. The MFE01 strain has a very active type six secretion system that can kill some competitive bacteria. Furthermore, MFE01 emits numerous volatile organic compounds, including 1-undecene, which contributes to the aerial inhibition of growth. Finally, MFE01 appears to be deprived of -acyl homoserine lactone synthase. The main objective of this study was to explore the role of 1-undecene in the communication of MFE01. We constructed a mutant affected in gene encoding the enzyme responsible for 1-undecene synthesis to provide further insight into the role of 1-undecene in MFE01. First, we studied the impacts of this mutation both on volatile organic compounds emission, using headspace solid-phase microextraction combined with gas chromatography-mass spectrometry and on long-range inhibition. Then, we analyzed influence of 1-undecene on MFE01 coordinated phenotypes, including type six secretion system activity and biofilm formation. Next, to test the ability of MFE01 to synthesize -acyl homoserine lactones in our conditions, we investigated the presence of corresponding genes across the MFE01 genome and we exposed its biofilms to an acyl homoserine lactone-degrading enzyme. Finally, we examined the effects of 1-undecene emission on MFE01 biofilm maturation and aerial communication using an original experimental set-up. This study demonstrated that the Δ mutant is impaired in biofilm maturation. An exposure of the Δ mutant to the volatile compounds emitted by MFE01 during the biofilm development restored the biofilm maturation process. These findings indicate that MFE01 uses 1-undecene emission for aerial communication, reporting for the first time this volatile organic compound as bacterial intraspecific communication signal.
PubMed: 37908545
DOI: 10.3389/fmicb.2023.1264801 -
Journal of Hazardous Materials Jun 2024As well known, surface discharge cold plasma has efficient inactivation ability and a variety of RONS are main active particles for inactivation, but their synergistic...
Insight into the surface discharge cold plasma efficient inactivation of Pseudomonas fluorescens in water based on exogenous reactive oxygen and nitrogen species: Synergistic mechanism and energy benefits.
As well known, surface discharge cold plasma has efficient inactivation ability and a variety of RONS are main active particles for inactivation, but their synergistic mechanism is still not clear. Therefore, surface discharge cold plasma system was applied to treat Pseudomonas fluorescens to study bacterial inactivation mechanism and energy benefit. Results showed that energy efficiency was directly proportional to applied voltage and inversely proportional to initial concentration. Cold plasma treatment for 20 min was inactivated by approximately > 4-logPseudomonas fluorescens and application of •OH and O scavengers significantly improved survival rate. In addition, •OH and O destroyed cell membrane structure and membrane permeability, which promoted diffusion of RONS into cells and affecting energy metabolism and antioxidant capacity, leading to bacterial inactivation. Furthermore, accumulation of intracellular NO and ONOOH was related to infiltration of exogenous RNS, while accumulation of •OH, HO, O, O was the result of joint action of endogenous and exogenous ROS. Transcriptome analysis revealed that different RONS of cold plasma were responsible for Pseudomonas fluorescens inactivation and related to activation of intracellular antioxidant defense system and regulation of genes expression related to amino acid metabolism and energy metabolism, which promoting cellular process, catalytic activity and other biochemical pathways.
PubMed: 38943891
DOI: 10.1016/j.jhazmat.2024.134984 -
Frontiers in Microbiology 2023Although the bacterial composition of boar ejaculate has been extensively studied, the bacterial composition of extended boar semen is often overlooked, despite the...
Although the bacterial composition of boar ejaculate has been extensively studied, the bacterial composition of extended boar semen is often overlooked, despite the potential risks these microorganisms may pose to the long-term preservation of extended boar semen at 15-17°C. In this study, we characterized the bacterial community composition of extended semen and discovered that spp. was the dominant flora. The dominant strains were further isolated and identified as a potential new species in the group and named strain, which had adverse effects on sperm quality and was better adapted to growth at 17°C. Antimicrobial susceptibility testing showed that the strain was resistant to all commonly used veterinary antibiotics. Whole-genome sequencing (WGS) and genome annotation revealed the large genetic structure and function [7,253,751 base pairs and 6,790 coding sequences (CDSs)]. Comparative genomic analysis with the closest type strains showed that the strain predicted more diversity of intrinsic and acquired resistance genes to multi-antimicrobial agents. Taken together, our study highlights a problem associated with the long-term storage of extended boar semen caused by a group strain with unique biological characteristics. It is essential to develop a new antibacterial solution for the long-term preservation of boar semen.
PubMed: 37869660
DOI: 10.3389/fmicb.2023.1279630 -
Fish & Shellfish Immunology Dec 2023Polyvalent antibodies can resist multiple bacterial species, and immunoglobulin Y (IgY) antibody can be economically prepared in large quantities from egg yolk; further,...
Polyvalent antibodies can resist multiple bacterial species, and immunoglobulin Y (IgY) antibody can be economically prepared in large quantities from egg yolk; further, IgY polyvalent antibodies have application value in aquaculture. The outer membrane proteins (OMPs) PF1380 and ExbB of Pseudomonas fluorescens were expressed and purified, and the corresponding IgY antibodies were prepared. PF1380, ExbB, and the corresponding IgY antibodies could activate the innate immune responses of chicken and Carassius auratus. The passive immunization to C. auratus showed that the IgY antibodies of PF1380 and ExbB had an immune protection rate, down-regulated the expression of antioxidant-related factors (MDA, SOD, GSH-Px, and CAT) to reduce the antioxidant reaction, down-regulated the expression of inflammation-related genes (IL-6, IL-8, TNF-α, and IL-1β) to reduce the inflammatory reaction, maintained the integrity of visceral tissue structure, and reduced apoptosis and damage of tissue cells in relation to P. fluorescens and Aeromonas hydrophila infections. Thus, the IgY antibodies of PF1380 and ExbB could be considered as passive polyvalent vaccine candidates in aquaculture.
Topics: Animals; Pseudomonas fluorescens; Membrane Proteins; Egg Yolk; Antioxidants; Immunoglobulins; Antibodies; Inflammation; Vaccines; Chickens
PubMed: 37944683
DOI: 10.1016/j.fsi.2023.109211 -
Scientific Reports Aug 2023The compound 2,4-diacetylphloroglucinol (DAPG) is a broad-spectrum antibiotic that is primarily produced by Pseudomonas spp. DAPG plays an important role in the...
The compound 2,4-diacetylphloroglucinol (DAPG) is a broad-spectrum antibiotic that is primarily produced by Pseudomonas spp. DAPG plays an important role in the biocontrol disease suppressing activity of Pseudomonas spp. In the current study, we report the discovery of the DAPG biosynthetic cluster in strains of Chromobacterium vaccinii isolated from Brazilian aquatic environments and the distribution of the biosynthetic cluster in the Chromobacterium genus. Phylogenetic analysis of the phlD protein suggests the biosynthetic cluster probably entered the genus of Chromobacterium after a horizontal gene transfer event with a member of the Pseudomonas fluorescens group. We were able to detect trace amounts of DAPG in wild type cultures and confirm the function of the cluster with heterologous expression in Escherichia coli. In addition, we identified and verified the presence of other secondary metabolites in these strains. We also confirmed the ability of C. vaccinii strains to produce bioactive pigment violacein and bioactive cyclic depsipeptide FR900359. Both compounds have been reported to have antimicrobial and insecticidal activities. These compounds suggest strains of C. vaccinii should be further explored for their potential as biocontrol agents.
Topics: Chromobacterium; Phylogeny; Anti-Bacterial Agents; Brazil; Escherichia coli; Pseudomonas
PubMed: 37653049
DOI: 10.1038/s41598-023-41277-0 -
Biofilm Dec 2023Biofilms are complex microbial communities embedded in extracellular matrix. Pathogens within the biofilm become more resistant to the antibiotics than planktonic...
Biofilms are complex microbial communities embedded in extracellular matrix. Pathogens within the biofilm become more resistant to the antibiotics than planktonic counterparts. Novel strategies are required to encounter biofilms. Exopolysaccharides are one of the major components of biofilm matrix and play a vital role in biofilm architecture. In previous studies, a glycosyl hydrolase, PslG, from was found to be able to inhibit biofilm formation by disintegrating exopolysaccharide in biofilms. Here, we investigate the potential spectrum of PslG homologous protein with anti-biofilm activity. One glycosyl hydrolase from , PslG, exhibits anti-biofilm activities and the key catalytic residues of PslG are conserved with those of PslG. PslG at concentrations as low as 50 nM efficiently inhibits the biofilm formation of and disassemble its preformed biofilm. Furthermore, PslG exhibits anti-biofilm activity on a series of , including and pv. . PslG stays active under various temperatures. Our findings suggest that glycosyl hydrolase PslG has potential to be a broad spectrum inhibitor on biofilm formation of a wide range of .
PubMed: 37928620
DOI: 10.1016/j.bioflm.2023.100155 -
The ISME Journal Oct 2023Proteobacteria primarily utilize acyl-homoserine lactones (AHLs) as quorum-sensing signals for intra-/interspecies communication to control pathogen infections....
Proteobacteria primarily utilize acyl-homoserine lactones (AHLs) as quorum-sensing signals for intra-/interspecies communication to control pathogen infections. Enzymatic degradation of AHL represents the major quorum-quenching mechanism that has been developed as a promising approach to prevent bacterial infections. Here we identified a novel quorum-quenching mechanism revealed by an effector of the type IVA secretion system (T4ASS) in bacterial interspecies competition. We found that the soil antifungal bacterium Lysobacter enzymogenes OH11 (OH11) could use T4ASS to deliver the effector protein Le1288 into the cytoplasm of another soil microbiome bacterium Pseudomonas fluorescens 2P24 (2P24). Le1288 did not degrade AHL, whereas its delivery to strain 2P24 significantly impaired AHL production through binding to the AHL synthase PcoI. Therefore, we defined Le1288 as LqqE1 (Lysobacter quorum-quenching effector 1). Formation of the LqqE1-PcoI complex enabled LqqE1 to block the ability of PcoI to recognize/bind S-adenosy-L-methionine, a substrate required for AHL synthesis. This LqqE1-triggered interspecies quorum-quenching in bacteria seemed to be of key ecological significance, as it conferred strain OH11 a better competitive advantage in killing strain 2P24 via cell-to-cell contact. This novel quorum-quenching also appeared to be adopted by other T4ASS-production bacteria. Our findings suggest a novel quorum-quenching that occurred naturally in bacterial interspecies interactions within the soil microbiome by effector translocation. Finally, we presented two case studies showing the application potential of LqqE1 to block AHL signaling in the human pathogen Pseudomonas aeruginosa and the plant pathogen Ralstonia solanacearum.
Topics: Humans; Quorum Sensing; Bacterial Proteins; Pseudomonas; Pseudomonas aeruginosa; Acyl-Butyrolactones; Pseudomonas fluorescens
PubMed: 37340074
DOI: 10.1038/s41396-023-01457-2