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International Journal of Molecular... Feb 2024(MI) colonizing metalworking fluids (MWFs) has been associated with chronic hypersensitivity pneumonitis (HP) in machinists. However, it is etiologically unclear why...
Differential Immunogenicity and Lung Disease-Inducing Potential of Genotypes and Impact of Co-Exposure with Pseudomonas: Optimizing a Mouse Model of Chronic Hypersensitivity Pneumonitis.
(MI) colonizing metalworking fluids (MWFs) has been associated with chronic hypersensitivity pneumonitis (HP) in machinists. However, it is etiologically unclear why only certain mycobacteria-contaminated fluids induce this interstitial lung disease. We hypothesized that this may be due to differential immunogenicity and the HP-inducing potential of MI strains/genotypes as well as the confounding effect of co-inhaled endotoxin-producers. To test this hypothesis, we optimized a chronic HP mouse model in terms of MI antigen dose, timepoint of sacrifice, and form of antigen (cell lysates vs. live cells) and compared six different field-isolated MI strains. Overall, MJY10 was identified as the most immunogenic and MJY4 (or MJY13) as the least immunogenic genotype based on lung pathoimmunological changes as well as Th1 cellular response (IFN-γ release). Infection with MI live cells induced a more severe phenotype than MI cell lysate. Co-exposure with caused a greater degree of lung innate immune response and granuloma formation but a diminished adaptive (Th1) immune response (IFN-γ) in the lung and spleen. In summary, this study led to the first demonstration of differential immunogenicity and the disease-inducing potential of field strains of MI and an interfering effect of the co-contaminating Pseudomonas. The improved chronic MI-HP mouse model and the identified polar pair of MI strains will facilitate future diagnostic and therapeutic research on this poorly understood environmental lung disease.
Topics: Mice; Animals; Pseudomonas; Alveolitis, Extrinsic Allergic; Lung; Genotype; Mycobacteriaceae
PubMed: 38396736
DOI: 10.3390/ijms25042058 -
RSC Advances Aug 2023is a cosmopolitan genus of bacteria found in soil, water, organic matter, plants and animals and known for the production of glycolipid and lipopeptide biosurfactants....
is a cosmopolitan genus of bacteria found in soil, water, organic matter, plants and animals and known for the production of glycolipid and lipopeptide biosurfactants. In this study bacteria (laboratory collection number 28E) isolated from soil collected in Spitsbergen were used for biosurfactant production. 16S rRNA sequencing and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) revealed that this isolate belongs to the species . In the present study, crude glycerol, a raw material obtained from several industrial processes, was evaluated as a potential low-cost carbon source to reduce the costs of lipopeptide production. Among several tested glycerols, a waste product of stearin production, rich in nitrogen, iron and calcium, ensured optimal conditions for bacterial growth. Biosurfactant production was evidenced by a reduction of surface tension (ST) and an increase in the emulsification index (%). According to Fourier-transform infrared spectroscopy (FTIR) and electrospray ionization mass spectrometry (ESI-MS), the biosurfactant was identified as viscosin. The critical micelle concentration (CMC) of lipopeptide was determined to be 20 mg L. Interestingly, viscosin production has been reported previously for , and . To the best of our knowledge, this is the first report on viscosin production by a 28E. The results indicated the potential of crude glycerol as a low-cost substrate to produce a lipopeptide biosurfactant with promising tensioactive and emulsifying properties.
PubMed: 37577095
DOI: 10.1039/d3ra03408a -
Microorganisms Aug 2023Forty-four bacterial strains isolated from greenhouse soil and beetroots were tested for their antagonistic activity against the plant-parasitic root-knot nematode (RKN)...
Forty-four bacterial strains isolated from greenhouse soil and beetroots were tested for their antagonistic activity against the plant-parasitic root-knot nematode (RKN) , which causes significant yield losses in a number of important crops worldwide. Through a novel combination of in vitro and on planta screening assays, spp. 105 and 108 were identified as the most promising bacterial isolates. Both strains were evaluated for their potential to control different RKN population densities and as root protectants against nematode infestation. Regardless of the application method, both strains significantly reduced root galling caused by . These two strains were subjected to whole genome sequencing and de novo genome assembly as a basis for phylogenetic and future functional characterization. Phylogenetic analysis revealed that both strains cluster within the clade among previously characterized RKN antagonists and -based biocontrol agents of plant diseases.
PubMed: 37630571
DOI: 10.3390/microorganisms11082011 -
Transfusion Medicine and Hemotherapy :... Apr 2024Bacterial contamination of blood products presumably occurs mainly during blood collection, starting from low initial concentrations of 10-100 colony-forming units...
INTRODUCTION
Bacterial contamination of blood products presumably occurs mainly during blood collection, starting from low initial concentrations of 10-100 colony-forming units (CFUs) per bag. As little is known about bacterial growth behavior and distribution in stored whole blood (WB) and WB-derived blood products, this study aims to provide data on this subject.
METHODS
WB units were inoculated with transfusion-relevant bacterial species (; = 12 for each species), stored for 22-24 h at room temperature, and then centrifuged for separation into plasma, red blood cells (RBCs), and buffy coats (BCs). The latter were pooled with 3 random donor BCs and one unit of PAS-E each to yield plasma-reduced platelet concentrates (PCs). Samples for bacterial colony counting were collected after WB storage and immediately after blood component production. Sterility testing in PCs ( = 12 for each species) was performed by bacterial culture after 7 days of storage.
RESULTS
Bacterial growth in WB varied remarkably between donations and species. Streptococcus species produced the highest titers in WB, whereas , , and did not multiply. Centrifugation resulted in preferential accumulation of bacteria in BCs, with titers of up to 3.5 × 10 CFU/mL in BCs and up to ≤0.9 × 10 CFU/mL in BC-derived PCs. Overall, 72/144 PCs (50%) tested positive for bacteria after storage. Sterility test results were species-dependent, ranging from 12 of 12 PCs tested positive for to 1 of 12 PCs positive for . Bacterial contamination of RBC and plasma units was much less common and was associated with higher initial bacterial counts in the parent WB units.
CONCLUSIONS
Bacterial growth in WB is species-dependent and varies greatly between donations. Preferential accumulation of bacteria in BCs during manufacturing is a critical determinant of the contamination risk of BC-derived pooled PCs.
PubMed: 38584696
DOI: 10.1159/000536242 -
Ecotoxicology and Environmental Safety Apr 2024Lead (Pb) is one of the most dreadful non-essential elements whose toxicity has been well reported worldwide due to its interference with the major plant functions and...
Synergistic application of Pseudomonas strains and compost mitigates lead (Pb) stress in sunflower (Helianthus annuus L.) via improved nutrient uptake, antioxidant defense and physiology.
Lead (Pb) is one of the most dreadful non-essential elements whose toxicity has been well reported worldwide due to its interference with the major plant functions and its overall yield. Bioremediation techniques comprising the application of beneficial microorganisms have gained attention in recent times owing to their ecofriendly nature. Addition of organic matter to soil has been reported to stimulate microbial activities. Compost application improves soil structure and binds toxic contaminants due to its larger surface area and presence of functional groups. Furthermore, it stimulates soil microbial activities by acting as C-source. So, in current study, we investigated the individual and synergistic potential of two lead (Pb)-tolerant Pseudomonas strains alongwith compost (1% w/w) in sustaining sunflower growth under Pb contaminated soil conditions. Lead chloride (PbCl) salt was used for raising desired Pb concentration (500 mg kg). Results revealed that Pb stress drastically affected all the measured attributes of sunflower plant, however joint application of rhizobacteria and compost counteracted these adverse effects. Among them, co-application of str-1 and compost proved to be significantly better than str-2, as its inoculation significantly improved shoot and root lengths (64 and 76%), leaf area and leaves plant (95 and 166%), 100-achene weight (200%), no. of flowers plant (138%), chl 'a', 'b' and carotenoid (86, 159 and 33%) contents in sunflower as compared to control treatments. Furthermore, inoculation of Pseudomonas fluorescens along with compost increased the NPK in achene (139, 200 and 165%), flavonoid and phenolic contents (258 and 185%) along with transpiration and photosynthetic rates (54 and 72%) in leaves as compared to control treatment under Pb contamination. In addition, Pb entry to roots, shoots and achene were significantly suppressed under by 87, 90 and 91% respectively due to integrated application of compost and str-1 as evident by maximum Pb-immobilization efficiency (97%) obtained in this treatment. Similarly, bioconcentration factors for roots, shoots and achene were found to be 0.58, 0.18 and 0.0055 with associated translocation factor (0.30), which also revealed phytostabilization of Pb under combined application of PGPR and compost. Since, phytoremediation of heavy metals under current scenario of increasing global population is inevitable, results of the current study concluded that tolerant PGPR species along with organic amendments such as compost can inhibit Pb uptake by sunflower and confer Pb tolerance via improved nutrient uptake, physiology, antioxidative defense and gas exchange.
Topics: Antioxidants; Helianthus; Pseudomonas; Lead; Composting; Biodegradation, Environmental; Plant Roots; Soil; Nutrients; Soil Pollutants
PubMed: 38479312
DOI: 10.1016/j.ecoenv.2024.116194 -
Journal of Evolutionary Biology Oct 2023Fitness effects of mutations may generally depend on temperature that influences all rate-limiting biophysical and biochemical processes. Earlier studies suggested that...
Fitness effects of mutations may generally depend on temperature that influences all rate-limiting biophysical and biochemical processes. Earlier studies suggested that high temperatures may increase the availability of beneficial mutations ('more beneficial mutations'), or allow beneficial mutations to show stronger fitness effects ('stronger beneficial mutation effects'). The 'more beneficial mutations' scenario would inevitably be associated with increased proportion of conditionally beneficial mutations at higher temperatures. This in turn predicts that populations in warm environments show faster evolutionary adaptation but suffer fitness loss when faced with cold conditions, and those evolving in cold environments become thermal-niche generalists ('hotter is narrower'). Under the 'stronger beneficial mutation effects' scenario, populations evolving in warm environments would show faster adaptation without fitness costs in cold environments, leading to a 'hotter is (universally) better' pattern in thermal niche adaptation. We tested predictions of the two competing hypotheses using an experimental evolution study in which populations of two model bacterial species, Escherichia coli and Pseudomonas fluorescens, evolved for 2400 generations at three experimental temperatures. Results of reciprocal transplant experiments with our P. fluorescens populations were largely consistent with the 'hotter is narrower' prediction. Results from the E. coli populations clearly suggested stronger beneficial mutation effects at higher assay temperatures, but failed to detect faster adaptation in populations evolving in warmer experimental environments (presumably because of limitation in the supply of genetic variation). Our results suggest that the influence of temperature on mutational effects may provide insight into the patterns of thermal niche adaptation and population diversification across thermal conditions.
Topics: Temperature; Escherichia coli; Adaptation, Physiological; Mutation; Acclimatization; Genetic Fitness
PubMed: 37750539
DOI: 10.1111/jeb.14225 -
Scientific Reports Oct 2023Studying bacterial adhesion to mineral surfaces is crucial for understanding soil properties. Recent research suggests that minimal coverage of sand particles with cell...
Studying bacterial adhesion to mineral surfaces is crucial for understanding soil properties. Recent research suggests that minimal coverage of sand particles with cell fragments significantly reduces soil wettability. Using atomic force microscopy (AFM), we investigated the influence of hypertonic stress on Pseudomonas fluorescens adhesion to four different minerals in water. These findings were compared with theoretical XDLVO predictions. To make adhesion force measurements comparable for irregularly shaped particles, we normalized adhesion forces by the respective cell-mineral contact area. Our study revealed an inverse relationship between wettability and the surface-organic carbon content of the minerals. This relationship was evident in the increased adhesion of cells to minerals with decreasing wettability. This phenomenon was attributed to hydrophobic interactions, which appeared to be predominant in all cell-mineral interaction scenarios alongside with hydrogen bonding. Moreover, while montmorillonite and goethite exhibited stronger adhesion to stressed cells, presumably due to enhanced hydrophobic interactions, kaolinite showed an unexpected trend of weaker adhesion to stressed cells. Surprisingly, the adhesion of quartz remained independent of cell stress level. Discrepancies between measured cell-mineral interactions and those calculated by XDLVO, assuming an idealized sphere-plane geometry, helped us interpret the chemical heterogeneity arising from differently exposed edges and planes of minerals. Our results suggest that bacteria may have a significant impact on soil wettability under changing moisture condition.
Topics: Soil; Pseudomonas fluorescens; Osmotic Pressure; Microscopy, Atomic Force; Minerals
PubMed: 37816775
DOI: 10.1038/s41598-023-44256-7 -
Scientific Reports Jan 2024Lipopeptides, derived from microorganisms, are promising surface-active compounds known as biosurfactants. However, the high production costs of biosurfactants,...
Lipopeptides, derived from microorganisms, are promising surface-active compounds known as biosurfactants. However, the high production costs of biosurfactants, associated with expensive culture media and purification processes, limit widespread industrial application. To enhance the sustainability of biosurfactant production, researchers have explored cost-effective substrates. In this study, crude glycerol was evaluated as a promising and economical carbon source in viscosinamide production by Pseudomonas fluorescens DR54. Optimization studies using the Box - Behnken design and response surface methodology were performed. Optimal conditions for viscosinamide production including glycerol 70.8 g/L, leucine 2.7 g/L, phosphate 3.7 g/L, and urea 9.3 g/L were identified. Yield of viscosinamide production, performed under optimal conditions, reached 7.18 ± 0.17 g/L. Preliminary characterization of viscosinamide involved the measurement of surface tension. The critical micelle concentration of lipopeptide was determined to be 5 mg/L. Furthermore, the interactions between the viscosinamide and lipase from Candida rugosa (CRL) were investigated by evaluating the impact of viscosinamide on lipase activity and measuring circular dichroism. It was observed that the α-helicity of CRL increases with increasing viscosinamide concentration, while the random coil structure decreases.
Topics: Pseudomonas fluorescens; Glycerol; Surface-Active Agents; Lipopeptides; Lipase; Peptides, Cyclic
PubMed: 38233450
DOI: 10.1038/s41598-024-51179-4 -
MSystems Feb 2024Root-associated microorganisms play an important role in plant health, such as plant growth-promoting rhizobacteria (PGPR) from the and genera. Although bacterial...
Root-associated microorganisms play an important role in plant health, such as plant growth-promoting rhizobacteria (PGPR) from the and genera. Although bacterial consortia including these two genera would represent a promising avenue to efficient biofertilizer formulation, we observed that root colonization is decreased by the presence of and . To determine if can adapt to the inhibitory effect of on roots, we conducted adaptative laboratory evolution experiments with in mono-association or co-cultured with on tomato plant roots. Evolved isolates with various colony morphology and stronger colonization capacity of both tomato plant and roots emerged rapidly from the two evolution experiments. Certain evolved isolates also had better fitness on the root in the presence of other species. In all independent lineages, whole-genome resequencing revealed non-synonymous mutations in genes or encoding regulators involved in repressing biofilm development, suggesting their involvement in enhanced root colonization. These findings provide insights into the molecular mechanisms underlying adaptation to root colonization and highlight the potential of directed evolution to enhance the beneficial traits of PGPR.IMPORTANCEIn this study, we aimed to enhance the abilities of the plant-beneficial bacterium to colonize plant roots in the presence of competing bacteria. To achieve this, we conducted adaptive laboratory experiments, allowing to evolve in a defined environment. We successfully obtained strains of that were more effective at colonizing plant roots than the ancestor strain. To identify the genetic changes driving this improvement, we sequenced the genomes of these evolved strains. Interestingly, mutations that facilitated the formation of robust biofilms on roots were predominant. Many of these evolved isolates also displayed the remarkable ability to outcompete species. Our research sheds light on the mutational paths selected in to thrive in root environments and offers exciting prospects for improving beneficial traits in plant growth-promoting microorganisms. Ultimately, this could pave the way for the development of more effective biofertilizers and sustainable agricultural practices.
Topics: Bacillus subtilis; Bacillus; Biofilms; Arabidopsis; Pseudomonas fluorescens
PubMed: 38206029
DOI: 10.1128/msystems.00843-23 -
MSphere May 2024The genome of encodes >50 proteins predicted to play a role in bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP)-mediated biofilm formation. We built a...
The genome of encodes >50 proteins predicted to play a role in bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP)-mediated biofilm formation. We built a network representation of protein-protein interactions and extracted key information via multidimensional scaling (i.e., principal component analysis) of node centrality measures, which measure features of proteins in a network. Proteins of different domain types (diguanylate cyclase, dual domain, phosphodiesterase, PilZ) exhibit unique network behavior and can be accurately classified by their network centrality values (i.e., roles in the network). The predictive power of protein-protein interactions in biofilm formation indicates the possibility of localized pools of c-di-GMP. A regression model showed a statistically significant impact of protein-protein interactions on the extent of biofilm formation in various environments. These results highlight the importance of a localized c-di-GMP signaling, extend our understanding of signaling by this second messenger beyond the current "Bow-tie Model," support a newly proposed "Hub Model," and suggest future avenues of investigation.
Topics: Cyclic GMP; Biofilms; Pseudomonas fluorescens; Bacterial Proteins; Protein Interaction Maps; Gene Expression Regulation, Bacterial; Phosphorus-Oxygen Lyases; Escherichia coli Proteins
PubMed: 38591888
DOI: 10.1128/msphere.00178-24