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BMC Research Notes Dec 2022Staphylococcus epidermidis is a skin colonizer and a major cause of nosocomial infections that can lead to sepsis. It causes opportunistic infections by forming biofilms...
OBJECTIVE
Staphylococcus epidermidis is a skin colonizer and a major cause of nosocomial infections that can lead to sepsis. It causes opportunistic infections by forming biofilms on medical devices, which are hard to control with conventional antibiotics. In an attempt to develop its biofilm inhibitors, the culture supernatant (CS) of Pseudomonas fluorescens was assessed. This study examined the effect of the CS on S. epidermidis 1457 biofilm formation, the characteristics of inhibitors in the CS, and the differential gene expression of S. epidermidis when treated with the CS.
RESULTS
P. fluorescens CS specifically targeted the maturation stage of S. epidermidis biofilm formation while not affecting planktonic growth. RT-qPCR analysis revealed that P. fluorescens CS significantly downregulated S. epidermidis ica genes and upregulated an ica repressor, tcaR. This indicates that the CS reduced polysaccharide intercellular adhesin synthesis, a major component of the S. epidermidis 1457 biofilm matrix. Further studies are required to elucidate the specific inhibitory components in the CS and their mechanism of action. Our results indicate that inhibitors in the P. fluorescens CS may have a significant value for inhibiting S. epidermidis biofilm. Combinations of specific inhibitors from the CS and antibiotics against staphylococci may provide an effective measure to control S. epidermidis biofilm formation while avoiding antibiotic resistance and compensating the attenuated effectiveness of antibiotics on biofilms.
Topics: Humans; Staphylococcus epidermidis; Pseudomonas fluorescens; Biofilms; Polysaccharides, Bacterial; Anti-Bacterial Agents; Staphylococcus; Staphylococcal Infections
PubMed: 36510276
DOI: 10.1186/s13104-022-06257-z -
Biomolecules Nov 2021Genome-wide analysis of plant-growth-promoting strain SS101 (SS101) followed by site-directed mutagenesis previously suggested that sulfur assimilation may play an...
Genome-wide analysis of plant-growth-promoting strain SS101 (SS101) followed by site-directed mutagenesis previously suggested that sulfur assimilation may play an important role in growth promotion and induced systemic resistance in . Here, we investigated the effects of sulfur metabolism in SS101 on growth, defense, and shoot metabolomes of and the Brassica crop, Broccoli. Root tips of seedlings of and two Broccoli cultivars were treated with SS101 or with a mutant disrupted in the adenylsulfate reductase , a key gene in cysteine and methionine biosynthesis. Phenotyping of plants treated with wild-type SS101 or its mutant revealed that sulfur assimilation in SS101 was associated with enhanced growth of but with a reduction in shoot biomass of two Broccoli cultivars. Untargeted metabolomics revealed that -mediated sulfur assimilation in SS101 had significant effects on shoot chemistry of , in particular on chain elongation of aliphatic glucosinolates (GLSs) and on indole metabolites, including camalexin and the growth hormone indole-3-acetic acid. In Broccoli, SS101 sulfur assimilation significantly upregulated the relative abundance of several shoot metabolites, in particular, indolic GLSs and phenylpropanoids. These metabolome changes in Broccoli plants coincided with SS101-mediated suppression of leaf infections by . Our study showed the metabolic interconnectedness of plants and their root-associated microbiota.
Topics: Arabidopsis; Brassicaceae; Glucosinolates; Pseudomonas fluorescens
PubMed: 34827700
DOI: 10.3390/biom11111704 -
Journal of Dairy Science Jun 2021New cases of blue cheese discoloration has led to recent research to identify the causal agent and factors that favor blue pigment appearing. Nonetheless, very few...
New cases of blue cheese discoloration has led to recent research to identify the causal agent and factors that favor blue pigment appearing. Nonetheless, very few reports have described the source of contamination and the measurements to eradicate the microbiological source on cheese farms by determining the relation between blue discoloration on fresh cheese and the Pseudomonas fluorescens group. Thus, 60 samples from a cheese farm (cheese, equipment surfaces, tap water, and raw and pasteurized milk) were analyzed by phenotypical, MALDI-TOF, 16S rRNA sequencing and pulsed-field gel electrophoresis tests to determine the causal agent. The results obtained by pulsed-field gel electrophoresis with restriction enzymes XbaI and SpeI confirmed tap water as the initial contaminated source. The above-mentioned result was essential to avoid Pseudomonas contamination due to the most residual microorganisms being inactivated through a new disinfection program.
Topics: Animals; Cheese; Dairy Products; Electrophoresis, Gel, Pulsed-Field; Milk; Pseudomonas; Pseudomonas fluorescens; RNA, Ribosomal, 16S
PubMed: 33838893
DOI: 10.3168/jds.2020-19517 -
Bioinformation 2023Increased amounts of toxicants may cause sever health issues in humans as well as in aquatic life. Scientists are developing new technologies to combat these problems....
Increased amounts of toxicants may cause sever health issues in humans as well as in aquatic life. Scientists are developing new technologies to combat these problems. Biological methods of detoxification are always beneficial for the environment. Pseudomonas fluorescens is known for its detoxification capacity. In this study stains were isolated from different locations of the Ha'il region, Saudia Arabia. The microbial strain AM-1 displayed resistance to heavy metals (Cr6+, Ni2+, Cd2+, Pb2+) and pesticides (BHC, 2,4-D, Mancozeb) at pollutant levels typical of highly contaminated areas. Additionally, AM-1 exhibited substantial detoxification potential, reducing toxicity by 40.67% for heavy metals and 47.4% for pesticides at 3x concentrations. These findings suggest that the AM-1 strain supports environmental remediation and pollution mitigation. Atomic absorption spectrometry (AAS) results exhibited bioremediation efficiency for metals Cr, Ni, and Pb using immobilized cells of AM-1 isolate, estimated to be 60.57%, 68.4%, and 53.93% respectively. These findings show that AM-1 strain has a potential role in bioremediation of water pollutants and may have future implications in wastewater treatment.
PubMed: 37928494
DOI: 10.6026/97320630019901 -
Molecular Microbiology Feb 2022Many bacteria form mats at the air-liquid interface of static microcosms. These structures typically involve the secretion of exopolysaccharides, the production of which...
Many bacteria form mats at the air-liquid interface of static microcosms. These structures typically involve the secretion of exopolysaccharides, the production of which is often controlled by the secondary messenger c-di-GMP. Mechanisms of mat formation have been particularly well characterized in Pseudomonas fluorescens SBW25; stimuli or mutations that increase c-di-GMP production by diguanylate cyclases (WspR, AwsR, and MwsR) result in the secretion of cellulose and mat formation. Here, we characterize and compare mat formation in two close relatives of SBW25: Pseudomonas simiae PICF7 and P. fluorescens A506. We find that PICF7-the strain more closely related to SBW25-can form mats through mutations affecting the activity of the same three diguanylate cyclases as SBW25. However, instead of cellulose, these mutations activate production of the exopolysaccharide Pel. We also provide evidence for at least two further-as yet uncharacterized-routes to mat formation by PICF7. P. fluorescens A506, while retaining the same mutational routes to mat formation as SBW25 and PICF7, preferentially forms mats by a semi-heritable mechanism that culminates in Psl and Pga over-production. Our results demonstrate a high level of evolutionary flexibility in the molecular and structural routes to mat formation, even among close relatives.
Topics: Biofilms; Biological Evolution; Cyclic GMP; Mutation; Pseudomonas; Pseudomonas aeruginosa; Pseudomonas fluorescens
PubMed: 34856020
DOI: 10.1111/mmi.14855 -
Microbiology (Reading, England) Aug 2023Evolutionary innovation of transcription factors frequently drives phenotypic diversification and adaptation to environmental change. Transcription factors can gain or...
Evolutionary innovation of transcription factors frequently drives phenotypic diversification and adaptation to environmental change. Transcription factors can gain or lose connections to target genes, resulting in novel regulatory responses and phenotypes. However the frequency of functional adaptation varies between different regulators, even when they are closely related. To identify factors influencing propensity for innovation, we utilise a SBW25 strain rendered incapable of flagellar mediated motility in soft-agar plates via deletion of the flagellar master regulator (). This bacterium can evolve to rescue flagellar motility via gene regulatory network rewiring of an alternative transcription factor to rescue activity of FleQ. Previously, we have identified two members (out of 22) of the RpoN-dependent enhancer binding protein (RpoN-EBP) family of transcription factors (NtrC and PFLU1132) that are capable of innovating in this way. These two transcription factors rescue motility repeatably and reliably in a strict hierarchy – with NtrC the only route in a ∆ background, and PFLU1132 the only route in a ∆∆ background. However, why other members in the same transcription factor family have not been observed to rescue flagellar activity is unclear. Previous work shows that protein homology cannot explain this pattern within the protein family (RpoN-EBPs), and mutations in strains that rescued motility suggested high levels of transcription factor expression and activation drive innovation. We predict that mutations that increase expression of the transcription factor are vital to unlock evolutionary potential for innovation. Here, we construct titratable expression mutant lines for 11 of the RpoN-EBPs in . We show that in five additional RpoN-EBPs (FleR, HbcR, GcsR, DctD, AauR and PFLU2209), high expression levels result in different mutations conferring motility rescue, suggesting alternative rewiring pathways. Our results indicate that expression levels (and not protein homology) of RpoN-EBPs are a key constraining factor in determining evolutionary potential for innovation. This suggests that transcription factors that can achieve high expression through few mutational changes, or transcription factors that are active in the selective environment, are more likely to innovate and contribute to adaptive gene regulatory network evolution.
Topics: Transcription Factors; Transcription, Genetic; Gene Expression Regulation; Pseudomonas fluorescens; Gene Expression Regulation, Bacterial; Bacterial Proteins
PubMed: 37584667
DOI: 10.1099/mic.0.001378 -
Journal of Food Protection Aug 2021Pseudomonas fluorescens is a specific spoilage microorganism of refrigerated marine fish, and is highly adapted to low temperature. Cold shock proteins (CSPs) play an...
ABSTRACT
Pseudomonas fluorescens is a specific spoilage microorganism of refrigerated marine fish, and is highly adapted to low temperature. Cold shock proteins (CSPs) play an important role in cold adaptation of bacteria. In this study, CSP genes were identified from the genome of P. fluorescens PF08 by search of the conserved domain of CSPs with HMMER software, and the CSP physicochemical properties, structures, and functions were analyzed through bioinformatics. Five typical CSPs were identified in the P. fluorescens PF08 genome (PfCSPs). All five PfCSPs are small hydrophilic acidic proteins with a molecular mass of ca. 7.4 kDa. They are located in the cytoplasm and are nonsecretory and nontransmembrane proteins. Multiple sequence alignment analysis indicated that the CSPs are highly conserved between species, especially in DNA-binding sites and RNA-binding motifs that can bind to single-stranded DNA and RNA. The five PfCSPs clustered with CspD from Escherichia coli and Salmonella Typhimurium, which suggests a close homology and high functional similarity among the five PfCSPs and CspD. The secondary and tertiary structures of the PfCSPs are in accordance with the characteristics of the CSP family, and ligand binding sites with higher likelihood were found in PfCSPs. The five PfCSPs were predicted to interact with some of the same proteins that are involved in virulence, stress responses (including to low temperature), cell growth, ribosome assembly, and RNA degradation. The results provide further elucidation of the function of CSPs in adaptation to low temperatures by P. fluorescens.
Topics: Amino Acid Sequence; Animals; Bacterial Proteins; Cold Shock Proteins and Peptides; Cold Temperature; Computer Simulation; Heat-Shock Proteins; Pseudomonas fluorescens
PubMed: 33852731
DOI: 10.4315/JFP-21-044 -
International Journal of Molecular... Nov 2020Endophytic bacteria hold tremendous potential for use as biocontrol agents. Our study aimed to investigate the biocontrol activity of BRZ63, a new endophyte of oilseed...
Endophytic bacteria hold tremendous potential for use as biocontrol agents. Our study aimed to investigate the biocontrol activity of BRZ63, a new endophyte of oilseed rape ( L.) against W70, K, K2291, and . In addition, features crucial for biocontrol, plant growth promotion, and colonization were assessed and linked with the genome sequences. The in vitro tests showed that BRZ63 significantly inhibited the mycelium growth of all tested pathogens and stimulated germination and growth of oilseed rape seedlings treated with fungal pathogens. The BRZ63 strain can benefit plants by producing biosurfactants, siderophores, indole-3-acetic acid (IAA), 1-aminocyclopropane-1-carboxylate (ACC) deaminase, and ammonia as well as phosphate solubilization. The abilities of exopolysaccharide production, autoaggregation, and biofilm formation additionally underline its potential to plant colonization and hence biocontrol. The effective colonization properties of the BRZ63 strain were confirmed by microscopy observations of EGFP-expressing cells colonizing the root surface and epidermal cells of Col-0. Genome mining identified many genes related to the biocontrol process, such as transporters, siderophores, and other secondary metabolites. All analyses revealed that the BRZ63 strain is an excellent endophytic candidate for biocontrol of various plant pathogens and plant growth promotion.
Topics: Ammonia; Arabidopsis; Ascomycota; Bacterial Proteins; Biological Control Agents; Brassica napus; Carbon-Carbon Lyases; Colletotrichum; Data Mining; Endophytes; Fusarium; Genome, Bacterial; Indoleacetic Acids; Phylogeny; Plant Diseases; Plant Roots; Polysaccharides, Bacterial; Pseudomonas fluorescens; Rhizoctonia; Seedlings; Siderophores; Surface-Active Agents
PubMed: 33228091
DOI: 10.3390/ijms21228740 -
Applied and Environmental Microbiology Nov 20202P24 is a rhizosphere bacterium that protects many crop plants against soilborne diseases caused by phytopathogens. The PcoI/PcoR quorum-sensing (QS) system and...
2P24 is a rhizosphere bacterium that protects many crop plants against soilborne diseases caused by phytopathogens. The PcoI/PcoR quorum-sensing (QS) system and polyketide antibiotic 2,4-diacetylphloroglucinol (2,4-DAPG) are particularly relevant to the strain's biocontrol potential. In this study, we investigated the effects of c-di-GMP on the biocontrol activity of strain 2P24. The expression of the diguanylate cyclase (YedQ) and phosphodiesterase (YhjH) in 2P24 significantly increased and decreased the cellular concentration of c-di-GMP, respectively. The production of the QS signals -acyl homoserine lactones (AHLs) and 2,4-DAPG was negatively regulated by c-di-GMP in 2P24. The regulatory proteins RsmA and RsmE were positively regulated by c-di-GMP. Genomic analysis revealed that 2P24 has 23 predicted proteins that contain c-di-GMP-synthesizing or -degrading domains. Among these proteins, C0J56_12915, C0J56_13325, and C0J56_27925 contributed to the production of c-di-GMP and were also involved in the regulation of the QS signal and antibiotic 2,4-DAPG production in Overexpression of C0J56_12915, C0J56_13325, and C0J56_27925 in 2P24 impaired its root colonization and biocontrol activities. Taken together, these results demonstrated that c-di-GMP played an important role in fine-tuning the biocontrol traits of In various bacteria, the bacterial second messenger c-di-GMP influences a wide range of cellular processes. However, the function of c-di-GMP on biocontrol traits in the plant-beneficial rhizobacteria remains largely unclear. The present work shows that the QS system and polyketide antibiotic 2,4-DAPG production are regulated by c-di-GMP through RsmA and RsmE proteins in 2P24. The diguanylate cyclases (DGCs) C0J56_12915, C0J56_13325, and C0J56_27925 are especially involved in regulating the biocontrol traits of 2P24. Our work also demonstrated a connection between the Gac/Rsm cascade and the c-di-GMP signaling pathway in .
Topics: Bacterial Proteins; Biological Control Agents; Cyclic GMP; Pseudomonas fluorescens; Quorum Sensing
PubMed: 33036989
DOI: 10.1128/AEM.02016-20 -
ACS Applied Materials & Interfaces May 2020Biofilm formation is most commonly combatted with antibiotics or biocides. However, proven toxicity and increasing resistance of bacteria increase the need for...
Biofilm formation is most commonly combatted with antibiotics or biocides. However, proven toxicity and increasing resistance of bacteria increase the need for alternative strategies to prevent adhesion of bacteria to surfaces. Chemical modification of the surfaces by tethering of functional polymer brushes or films provides a route toward antifouling coatings. Furthermore, nanorough or superhydrophobic surfaces can delay biofilm formation. Here we show that submicrometer-sized roughness can outweigh surface chemistry by testing the adhesion of to surfaces of different topography and wettability over long exposure times (>7 days). Gram-negative and positive bacterial strains are tested for comparison. We show that an irregular three-dimensional layer of silicone nanofilaments suppresses bacterial adhesion, both in the presence and absence of an air cushion. We hypothesize that a 3D topography can delay biofilm formation (i) if bacteria do not fit into the pores of the coating or (ii) if bending of the bacteria is required to adhere. Thus, such a 3D topography offers an underestimated possibility to design antibacterial surfaces that do not require biocides or antibiotics.
Topics: Bacterial Adhesion; Biofouling; Escherichia coli; Glass; Hydrocarbons, Fluorinated; Micrococcus luteus; Nanostructures; Pseudomonas fluorescens; Silicones; Wettability
PubMed: 32142252
DOI: 10.1021/acsami.9b22621