RESUMEN
Cadmium (Cd) in rice is a significant concern for its quality and safety. Currently, there is a crucial need to develop cost-effective and efficient ways to remove Cd or re-utilize Cd-contaminated rice. The food additive sodium erythorbate is produced via 2-ketogluconic acid (2KGA) fermentation by Pseudomonas plecoglossicida and lactonization using starch-rich raw materials, such as rice. We aimed to determine whether cadmium-contaminated rice can be used to produce sodium erythorbate. To achieve this aim, the migration of cadmium during the production of sodium erythorbate from Cd-contaminated rice was studied. Five rice varieties with different Cd contents from 0.10 to 0.68 mg/kg were used as raw materials. The results indicated the presence of Cd in rice and CaCO3 did not have a notable impact on the fermentation performance of 2KGA. The acidification of 2KGA fermentation broth, the addition of K4Fe(CN)6·3H2O and ZnSO4, and 2KGA purification using cation exchange effectively removed >98% of the Cd in the fermentation broth, but the 2KGA yield remained high at approximately 94%. The sodium erythorbate synthesized from Cd-contaminated rice was of high quality and free from Cd, meeting the requirements of the Chinese National Standard, GB 1886.28-2016. The study provided a safe and effective strategy for comprehensively utilizing Cd-contaminated rice to produce high value-added food additive.
Asunto(s)
Cadmio , Fermentación , Aditivos Alimentarios , Contaminación de Alimentos , Oryza , Oryza/química , Oryza/metabolismo , Oryza/microbiología , Cadmio/metabolismo , Cadmio/análisis , Contaminación de Alimentos/análisis , Aditivos Alimentarios/análisis , Aditivos Alimentarios/metabolismo , Pseudomonas/metabolismo , Azúcares Ácidos/metabolismo , Azúcares Ácidos/química , Azúcares Ácidos/análisisRESUMEN
Two strains of Fe/Mn oxidizing bacteria tolerant to high concentrations of multiple heavy metal(loid)s and efficient decontamination for them were screened. The surface of the bio-Fe/Mn oxides produced by the oxidation of Fe(II) and Mn(II) by Pseudomonas taiwanensis (marked as P4) and Pseudomonas plecoglossicida (marked as G1) contains rich reactive oxygen functional groups, which play critical roles in the removal efficiency and immobilization of heavy metal(loid)s in co-contamination system. The isolated strains P4 and G1 can grow well in the following environments: pH 5-9, NaCl 0-4%, and temperature 20-30°C. The removal efficiencies of Fe, Pb, As, Zn, Cd, Cu, and Mn are effective after inoculation of the strains P4 and G1 in the simulated water system (the initial concentrations of heavy metal(loid) were 1 mg/L), approximately reaching 96%, 92%, 85%, 67%, 70%, 54% and 15%, respectively. The exchangeable and carbonate bound As, Cd, Pb and Cu are more inclined to convert to the Fe-Mn oxide bound fractions in P4 and G1 treated soil, thereby reducing the phytoavailability and bioaccessible of heavy metal(loid)s. This research provides alternatives method to treat water and soil containing high concentrations of multi-heavy metal(loid)s.
Asunto(s)
Metales Pesados , Contaminantes del Suelo , Contaminantes Químicos del Agua , Contaminantes Químicos del Agua/metabolismo , Contaminantes Químicos del Agua/análisis , Contaminantes del Suelo/metabolismo , Oxidación-Reducción , Pseudomonas/metabolismo , Manganeso , Hierro/química , Hierro/metabolismo , Suelo/química , Biodegradación Ambiental , Microbiología del SueloRESUMEN
The Loess Plateau is one of the key areas for soil and water erosion control in China. Planting vegetation, such as Robinia pseudoacacia, is one of the mainstream methods to prevent soil and water erosion. However, the combination of abundant calcium ions and phosphate in the soil of the Loess Plateau limits the phosphorus nutrition of plants. In the present study, soil samples were collected under the R. pseudoacacia forest, from which two PSB strains with efficient phosphate solubilization capacities, named PSB2 and PSB7, were isolated and screened. The dissolved phosphate concentrations of their culture media were 9.68-fold and 11.61-fold higher, respectively, than that of the control group. After identification, PSB2 was classified as Pseudomonas and PSB7 as Inquilinus. This is the first time that Inquilinus has been isolated as a PSB from calcareous soil in the Loess Plateau. We then investigated the effects of different growth conditions on their phosphate solubilization capacities. Both strains effectively utilized glucose and ammonium nitrogen while maintaining high phosphate solubilization efficiency. In addition, PSB2 preferred to survive under neutral conditions and PSB7 under acidic conditions. Pot experiments indicated that the inoculation with PSB7 significantly increased the phosphorus content in the roots of R. pseudoacacia. These results imply the potential of this PSB as a phosphorus biofertilizer for R. pseudoacacia, which may be beneficial for soil and water management on the Loess Plateau.
Asunto(s)
Fosfatos , Raíces de Plantas , Rizosfera , Robinia , Microbiología del Suelo , Robinia/microbiología , Robinia/química , Fosfatos/metabolismo , China , Raíces de Plantas/microbiología , Suelo/química , Solubilidad , Fósforo/metabolismo , Bacterias/metabolismo , Bacterias/clasificación , Bacterias/aislamiento & purificación , Bacterias/genética , Pseudomonas/metabolismo , Pseudomonas/aislamiento & purificación , Pseudomonas/clasificación , Filogenia , ARN Ribosómico 16S/genéticaRESUMEN
BACKGROUND: Pseudomonas eucalypticola, a new species of the P. fluorescens group that generates most Pseudomonas-based biocontrol agents, has not been found in any plants other than Eucalyptus dunnii leaves. Except for antagonism to the growth of a few fungi, its features in plant growth promotion and disease control have not been evaluated. Here, we identified a similar species of P. eucalypticola, 1021Bp, from endophyte cultures of healthy leaves of English boxwood (Buxus sempervirens 'Suffruticosa') and investigated its antifungal activity, plant growth promotion traits, and potential for boxwood blight control. RESULTS: Colorimetric or plate assays showed the properties of 1021Bp in nitrogen fixation, phosphate solubilization, and production of indole-3-acetic acid (IAA) and siderophores, as well as the growth suppression of all five plant fungal pathogens, including causal agents of widespread plant diseases, gray mold, and anthracnose. Boxwood plant leaves received 87.4% and 65.8% protection from infection when sprayed with cell-free cultural supernatant (CFS) but not the resuspended bacterial cells at 108-9/mL of 1021Bp at one and seven days before inoculation (dbi) with boxwood blight pathogen, Calonectria pseudonaviculata, at 5 × 104 spores/mL. They also received similarly high protection with the 1021Bp cell culture without separation of cells and CFS at 14 dbi (67.5%), suggesting a key role of 1021Bp metabolites in disease control. CONCLUSIONS: Given the features of plant growth and health and its similarity to P. eucalypticola with the P. fluorescens lineage, 1021Bp has great potential to be developed as a safe and environmentally friendly biofungicide and biofertilizer. However, its metabolites are the major contributors to 1021Bp activity for plant growth and health. Application with the bacterial cells alone, especially with nonionic surfactants, may result in poor performance unless survival conditions are present.
Asunto(s)
Enfermedades de las Plantas , Hojas de la Planta , Pseudomonas , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/prevención & control , Pseudomonas/genética , Pseudomonas/crecimiento & desarrollo , Pseudomonas/metabolismo , Hojas de la Planta/microbiología , Antibiosis , Ácidos Indolacéticos/metabolismo , Hongos/crecimiento & desarrollo , Hongos/genética , Hongos/clasificación , Hongos/efectos de los fármacos , Sideróforos/metabolismo , Endófitos/metabolismo , Endófitos/genética , Desarrollo de la Planta , Agentes de Control Biológico , Antifúngicos/farmacología , Antifúngicos/metabolismoRESUMEN
Plant growth-promoting rhizobacteria (PGPR) have been reported to suppress various diseases as potential bioagents. It can inhibit disease occurrence through various means such as directly killing pathogens and inducing systemic plant resistance. In this study, a bacterium isolated from soil showed significant inhibition of Valsa mali. Morphological observations and phylogenetic analysis identified the strain as Pseudomonas thivervalensis, named K321. Plate confrontation assays demonstrated that K321 treatment severely damaged V. mali growth, with scanning electron microscopy (SEM) observations showing severe distortion of hyphae due to K321 treatment. In vitro twigs inoculation experiments indicated that K321 had good preventive and therapeutic effects against apple Valsa canker (AVC). Applying K321 on apples significantly enhanced the apple inducing systemic resistance (ISR), including induced expression of apple ISR-related genes and increased ISR-related enzyme activity. Additionally, applying K321 on apples can activate apple MAPK by enhancing the phosphorylation of MPK3 and MPK6. In addition, K321 can promote plant growth by solubilizing phosphate, producing siderophores, and producing 3-indole-acetic acid (IAA). Application of 0.2% K321 increased tomato plant height by 53.71%, while 0.1% K321 increased tomato fresh weight by 59.55%. Transcriptome analysis revealed that K321 can inhibit the growth of V. mali by disrupting the integrity of its cell membrane through inhibiting the metabolism of essential membrane components (fatty acids) and disrupting carbohydrate metabolism. In addition, transcriptome analysis also showed that K321 can enhance plant resistance to AVC by inducing ISR-related hormones and MAPK signaling, and application of K321 significantly induced the transcription of plant growth-related genes. In summary, an excellent biocontrol strain has been discovered that can prevent AVC by inducing apple ISR and directly killing V. mali. This study indicated the great potential of P. thivervalensis K321 for use as a biological agent for the control of AVC.
Asunto(s)
Malus , Enfermedades de las Plantas , Pseudomonas , Malus/microbiología , Enfermedades de las Plantas/prevención & control , Enfermedades de las Plantas/microbiología , Pseudomonas/fisiología , Ascomicetos/fisiología , Agentes de Control Biológico , Resistencia a la EnfermedadRESUMEN
The anti-diabetic drug metformin is one of the most widely prescribed medicines in the world. Together with its degradation product guanylurea, it is a major pharmaceutical pollutant in wastewater treatment plants and surface waters. An operon comprising two genes of the ureohydrolase family in Pseudomonas and Aminobacter species has recently been implicated in metformin degradation. However, the corresponding proteins have not been characterized. Here we show that these genes encode a Ni2+-dependent enzyme that efficiently and specifically hydrolyzes metformin to guanylurea and dimethylamine. The active enzyme is a heteromeric complex of α- and ß- subunits in which only the α-subunits contain the conserved His and Asp residues for the coordination of two Ni2+ ions in the active site. A crystal structure of metformin hydrolase reveals an α2ß4 stoichiometry of the hexameric complex, which is unprecedented in the ureohydrolase family. By studying a closely related but more widely distributed enzyme, we find that the putative predecessor specifically hydrolyzes dimethylguanidine instead of metformin. Our findings establish the molecular basis for metformin hydrolysis to guanylurea as the primary pathway for metformin biodegradation and provide insight into the recent evolution of ureohydrolase family proteins in response to an anthropogenic compound.
Asunto(s)
Metformina , Níquel , Metformina/metabolismo , Metformina/química , Níquel/metabolismo , Níquel/química , Ureohidrolasas/metabolismo , Ureohidrolasas/genética , Ureohidrolasas/química , Cristalografía por Rayos X , Dominio Catalítico , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/química , Hidrólisis , Biodegradación Ambiental , Pseudomonas/enzimología , Pseudomonas/genética , Modelos MolecularesRESUMEN
The relationships between plants and bacteria are essential in agroecosystems and bioinoculant development. The leaf endophytic Pseudomonas protegens E1BL2 was previously isolated from giant Jala maize, which is a native Zea mays landrace of Nayarit, Mexico. Using different Mexican maize landraces, this work evaluated the strain's plant growth promotion and biocontrol against eight phytopathogenic fungi in vitro and greenhouse conditions. Also, a plant field trial was conducted on irrigated fields using the hybrid maize Supremo. The grain productivity in this assay increased compared with the control treatment. The genome analysis of P. protegens E1BL2 showed putative genes involved in metabolite synthesis that facilitated its beneficial roles in plant health and environmental adaptation (bdhA, acoR, trpE, speE, potA); siderophores (ptaA, pchC); and extracellular enzymes relevant for PGPB mechanisms (cel3, chi14), protection against oxidative stress (hscA, htpG), nitrogen metabolism (nirD, nit1, hmpA), inductors of plant-induced systemic resistance (ISR) (flaA, flaG, rffA, rfaP), fungal biocontrol (phlD, prtD, prnD, hcnA-1), pest control (vgrG-1, higB-2, aprE, pslA, ppkA), and the establishment of plant-bacteria symbiosis (pgaA, pgaB, pgaC, exbD). Our findings suggest that P. protegens E1BL2 significantly promotes maize growth and offers biocontrol benefits, which highlights its potential as a bioinoculant.
Asunto(s)
Enfermedades de las Plantas , Pseudomonas , Zea mays , Zea mays/microbiología , Zea mays/genética , Pseudomonas/genética , Pseudomonas/metabolismo , Enfermedades de las Plantas/microbiología , Enfermedades de las Plantas/genética , Hongos/genética , Agricultura/métodos , Genómica/métodos , Genoma BacterianoRESUMEN
In the aquaculture industry, biocides are routinely used to treat parasitosis in fish, and researchers are continually developing sustainable alternatives that can replace these harsh chemicals. In this context, the objective of this study was to evaluate the effectiveness of a new natural compound, BiokosTM, for the treatment against Epistylis sp. in Carassius auratus fish. The infestation was identified by the presence of whitish plaques on the integument of five animals, and the diagnosis was confirmed through skin scrapings. BiokosTM is a lipopeptide derived from the bacteria Pseudomonas that can destroy the functionality of the cell membrane of ciliated protozoa. The action of BiokosTM does not harm animals and the environment because the compound degrades into amino acids and fatty acids within days. A 0.15 m3 (150 L) aquarium was treated with an Ich-AwayTM water conditioner manufactured by the Danish company Sundew ApS, which has BiokosTM as the active ingredient. Six tablets were added to the water daily for two days, and new skin scrapings were performed. The fish were clinically well and no longer possessed lesions or parasites. The results obtained indicate that BiokosTM can be an innovative and more sustainable alternative for controlling epistyliasis in ornamental fish.
Asunto(s)
Enfermedades de los Peces , Carpa Dorada , Lipopéptidos , Pseudomonas , Animales , Carpa Dorada/parasitología , Enfermedades de los Peces/parasitología , Enfermedades de los Peces/tratamiento farmacológico , Pseudomonas/aislamiento & purificación , Pseudomonas/efectos de los fármacos , Lipopéptidos/uso terapéutico , Tensoactivos , Infecciones por Cilióforos/veterinaria , Infecciones por Cilióforos/tratamiento farmacológico , Hymenostomatida/efectos de los fármacosRESUMEN
BACKGROUND: Plants have evolved various defense mechanisms against insect herbivores, including the formation of physical barriers, the synthesis of toxic metabolites, and the activation of phytohormone responses. Although plant-associated microbiota influence plant growth and health, whether they play a role in plant defense against insect pests in natural ecosystems is unknown. RESULTS: Here, we show that leaves of beetle-damaged weeping willow (Salix babylonica) trees are more resistant to the leaf beetle Plagiodera versicolora (Coleoptera) than those of undamaged leaves. Bacterial community transplantation experiments demonstrated that plant-associated microbiota from the beetle-damaged willow contribute to the resistance of the beetle-damaged willow to P. versicolora. Analysis of the composition and abundance of the microbiome revealed that Pseudomonas spp. is significantly enriched in the phyllosphere, roots, and rhizosphere soil of beetle-damaged willows relative to undamaged willows. From a total of 49 Pseudomonas strains isolated from willows and rhizosphere soil, we identified seven novel Pseudomonas strains that are toxic to P. versicolora. Moreover, re-inoculation of a synthetic microbial community (SynCom) with these Pseudomonas strains enhances willow resistance to P. versicolora. CONCLUSIONS: Collectively, our data reveal that willows can exploit specific entomopathogenic bacteria to enhance defense against P. versicolora, suggesting that there is a complex interplay among plants, insects, and plant-associated microbiota in natural ecosystems.
Asunto(s)
Escarabajos , Hojas de la Planta , Pseudomonas , Salix , Animales , Salix/microbiología , Escarabajos/microbiología , Hojas de la Planta/microbiología , Microbiota , Rizosfera , Microbiología del Suelo , Herbivoria , Raíces de Plantas/microbiología , Enfermedades de las Plantas/microbiologíaRESUMEN
Bacteriocins are a class of proteins produced by bacteria that are toxic to other bacteria. These bacteriocins play a role in bacterial competition by helping to inhibit potential competitors. In this study, we isolated and purified a novel bacteriocin Pkmh, different from the previously reported bacteriocin PA166, from Pseudomonas sp. strain 166 by ammonium sulfate precipitation, dialysis membrane method, ion exchange chromatography, and gel filtration chromatography. SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) revealed that the molecular weight of Pkmh is approximately 35 kDa. Pkmh exhibited potent antimicrobial activity against bovine Mannheimia haemolytica (M. haemolytica) with low cytotoxicity, and lower hemolytic activity was observed. In addition, Pkmh retained antimicrobial activity at different pH ranges (2-10) and temperature conditions (40, 60, 80, 100 °C). Our analysis of its antimicrobial mechanism showed that Pkmh acts on bacterial cell membranes, increasing their permeability and leading to cell membrane rupture and death. In conclusion, Pkmh exhibited low hemolytic activity, low toxicity, and potent antibacterial effects, suggesting its potential as a promising candidate for clinical therapeutic drugs.
Asunto(s)
Antibacterianos , Bacteriocinas , Bacteriocinas/farmacología , Bacteriocinas/química , Antibacterianos/farmacología , Antibacterianos/química , Animales , Hemólisis/efectos de los fármacos , Mannheimia haemolytica/efectos de los fármacos , Pseudomonas/efectos de los fármacos , Bovinos , Pruebas de Sensibilidad Microbiana , Humanos , Peso Molecular , Membrana Celular/efectos de los fármacos , Membrana Celular/metabolismo , Temperatura , Concentración de Iones de HidrógenoRESUMEN
In this research, a novel active food packaging material was developed by blending starch, chitosan, and plant-based mucilage with zinc oxide nanoparticles. The polymeric nanocomposite film, created by incorporating zinc oxide nanoparticles into the mixture using a straightforward approach, was analyzed for its structural and functional attributes using FTIR, XRD, SEM, and TGA/DSC. These analyses revealed a robust interaction between the polymers' functional groups and the nanoparticles, forming a stable film. The film's mechanical properties, including tensile strength and Young's modulus, were high. It also showed reduced wettability and water solubility, enhancing water resistance. The biodegradability rate was 100 %. Antibacterial tests against Bacillus sp. and Pseudomonas sp. showed significant inhibition zones of 26 mm and 30 mm, respectively, demonstrating strong antibacterial effectiveness. The film's non-target toxicity was assessed through phytotoxicity experiments on Vigna angularis and soil nutrient evaluations, with no negative impact on plant growth or soil health observed. These results indicate that this nanocomposite is a safe, biocompatible option for food packaging.
Asunto(s)
Antibacterianos , Quitosano , Embalaje de Alimentos , Nanocompuestos , Almidón , Óxido de Zinc , Quitosano/química , Quitosano/farmacología , Nanocompuestos/química , Nanocompuestos/toxicidad , Óxido de Zinc/química , Óxido de Zinc/farmacología , Almidón/química , Antibacterianos/farmacología , Antibacterianos/química , Mucílago de Planta/química , Vigna , Nanopartículas/química , Fenómenos Mecánicos , Resistencia a la Tracción , Solubilidad , Pseudomonas/efectos de los fármacosRESUMEN
The increasing prevalence of antibiotic resistance, driven by the production of extended-spectrum beta-lactamases (ESBLs), presents a critical challenge to current medical treatments, particularly in clinical settings. Understanding the distribution and frequency of ESBL-producing bacteria is essential for developing effective control strategies. This study investigated the antibiotic resistance and extended-spectrum beta-lactamase (ESBL) production in bacterial isolates in clinical and non-clinical (food) specimens in Tabuk, KSA. A total of 57 bacterial isolates were analysed, with E. coli and Pseudomonas sp. being the most prevalent. High resistance rates were observed, particularly against third-generation cephalosporins in clinical isolates. ESBL screening revealed a significant prevalence in clinical samples (58.3%), with E. coli showing the highest positivity. Conversely, only a low percentage of food isolates were ESBL positive. Molecular analysis confirmed the presence of various ESBL genes, with blaCTX-M being the most frequent, predominantly found in clinical isolates. This study highlights the concerning levels of antibiotic resistance and ESBL production in the region, emphasising the need for effective infection control measures and prudent antibiotic use.
Asunto(s)
beta-Lactamasas , Humanos , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Pruebas de Sensibilidad Microbiana , Escherichia coli/efectos de los fármacos , Pseudomonas/efectos de los fármacos , Farmacorresistencia Bacteriana , Microbiología de AlimentosRESUMEN
Functional amyloids formed by the protein FapC in Pseudomonas bacteria are key structural components of Pseudomonas biofilms, which mediate chronic infections and also contribute to antimicrobial resistance. Here, we combine kinetic experiments with mechanistic modelling to probe the role of surfaces in FapC functional amyloid formation. We find that nucleation of new fibrils is predominantly heterogeneous in vitro, being catalysed by reaction vessel walls but not by the air/water interface. Removal of such interfaces by using microdroplets greatly slows heterogeneous nucleation and reveals a hitherto undetected fibril surface-catalysed "secondary nucleation" reaction step. We tune the degree of catalysis by varying the interface chemistry of the reaction vessel and by adding nanoparticles with tailored surface properties that catalyse fibril nucleation. In so doing, we discover that the rate of nucleation is controlled predominantly by the strength with which FapC binds to the catalytic sites on the interface, and by its surface area. Surprisingly, neither primary nucleation rate nor catalytic site binding strength appear closely correlated to the charge and hydrophilicity of the interface. This indicates the importance of considering experimental design in terms of surface chemistry of the reaction container while also highlighting the notion that fibril nucleation during protein aggregation is a heterogeneous process.
Asunto(s)
Amiloide , Propiedades de Superficie , Amiloide/química , Amiloide/metabolismo , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Cinética , Biopelículas , Pseudomonas/metabolismo , Nanopartículas/química , Interacciones Hidrofóbicas e HidrofílicasRESUMEN
The ability of bacteria to colonize diverse environmental niches is often linked to their competence in biofilm formation. It depends on the individual characteristics of a strain, the nature of the colonized surface (abiotic or biotic), or the availability of certain nutrients. Pseudomonas donghuensis P482 efficiently colonizes the rhizosphere of various plant hosts, but a connection between plant tissue colonization and the biofilm formation ability of this strain has not yet been established. We demonstrate here that the potential of P482 to form biofilms on abiotic surfaces and the structural characteristics of the biofilm are influenced by the carbon source available to the bacterium, with glycerol promoting the process. Also, the type of substratum, polystyrene or glass, impacts the ability of P482 to attach to the surface. Moreover, P482 mutants in genes associated with motility or chemotaxis, the synthesis of polysaccharides, and encoding proteases or regulatory factors, which affect biofilm formation on glass, were fully capable of colonizing the root tissue of both tomato and maize hosts. Investigating the role of cellular factors in biofilm formation using these plant-associated bacteria shows that the ability of bacteria to form biofilm on abiotic surfaces does not necessarily mirror its ability to colonize plant tissues. Our research provides a broader perspective on the adaptation of these bacteria to various environments.
Asunto(s)
Biopelículas , Carbono , Pseudomonas , Biopelículas/crecimiento & desarrollo , Pseudomonas/fisiología , Pseudomonas/metabolismo , Pseudomonas/genética , Carbono/metabolismo , Raíces de Plantas/microbiología , Rizosfera , Solanum lycopersicum/microbiología , Zea mays/microbiología , Vidrio , Adhesión Bacteriana , Glicerol/metabolismo , PoliestirenosRESUMEN
All bacterial strains studied retained the viability and ability to form both mono- and polycultural biofilms under conditions of long-term culturing in artificial seawater at 6°C and without addition of nutrients. Bacillus sp. and Pseudomonas japonica presumably stimulated the growth and reproduction of the pathogenic bacteria Listeria monocytogenes and Yersinia pseudotuberculosis. Preserved cell viability in a monoculture biofilm for a long period without adding a food source can indicate allolysis. At the same time, in a polycultural biofilm, the metabolites secreted by saprotrophic strains can stimulate the growth of L. monocytogenes and Y. pseudotuberculosis.
Asunto(s)
Biopelículas , Listeria monocytogenes , Yersinia pseudotuberculosis , Yersinia pseudotuberculosis/crecimiento & desarrollo , Yersinia pseudotuberculosis/fisiología , Biopelículas/crecimiento & desarrollo , Listeria monocytogenes/crecimiento & desarrollo , Listeria monocytogenes/fisiología , Animales , Agua de Mar/microbiología , Pseudomonas/fisiología , Pseudomonas/crecimiento & desarrollo , Pseudomonas/metabolismo , Interacciones Microbianas/fisiologíaRESUMEN
BACKGROUND: Pseudomonas juntendi is a newly identified opportunistic pathogen, of which we have limited understanding. P. juntendi strains are often multidrug resistant, which complicates clinical management of infection. METHODS: A strain of Pseudomonas juntendi (strain L4326) isolated from feces was characterized by MALDI-TOF-MS and Average Nucleotide Identity BLAST. This strain was further subject to whole-genome sequencing and Maximum Likelihood phylogenetic analysis. The strain was phenotypically characterized by antimicrobial susceptibility testing and conjugation assays. RESULTS: We have isolated the novel P. juntendi strain L4236, which was multidrug resistant, but retained sensitivity to amikacin. L4236 harbored a megaplasmid that encoded blaOXA-1 and a novel blaIMP-1 resistance gene variant. P. juntendi strain L4236 was phylogenetically related to P. juntendi strain SAMN30525517. CONCLUSION: A rare P. juntendi strain was isolated from human feces in southern China with a megaplasmid coharboring blaIMP-1-like and blaOXA-1. Antimicrobial selection pressures may have driven acquisition of drug-resistance gene mutations and carriage of the megaplasmid.
Asunto(s)
Farmacorresistencia Bacteriana Múltiple , Filogenia , Plásmidos , Pseudomonas , beta-Lactamasas , Pseudomonas/genética , Pseudomonas/aislamiento & purificación , Plásmidos/genética , beta-Lactamasas/genética , Farmacorresistencia Bacteriana Múltiple/genética , China , Humanos , Pruebas de Sensibilidad Microbiana , Antibacterianos/farmacología , Secuenciación Completa del Genoma , Heces/microbiología , Cromosomas Bacterianos/genética , Genoma BacterianoRESUMEN
The development of nontoxic antifouling coatings in static marine environments is urgent. Herein, the successful synthesis of sulfobetaine borneol fluorinated polymers (PEASBF) by a free radical polymerization method is reported. The PEASBF coatings exhibit outstanding antifouling activity, which effectively resists the adhesion of Bovine serum albumin (FITC-BSA adhesion rate: 0.5%), Pseudomonas sp. (Biofilm: 1.3 absorbance) and Navicula sp. (Diatom attachment rate: 33%). More importantly, the PEASBF coatings display outstanding fouling release properties, achieving a release rate of 98% for Navicula sp., and the absorbance of the Pseudomonas sp. biofilm is only 0.2 under 10 Pa shear stress. XPS and MD studies showed that the fluorinated/isobornyl groups induce more sulfobetaine groups to migrate toward polymer surfaces for intensify antifouling. Additionally, the chiral stereochemical structure of borneol enhances antifouling and fouling release ability of amphiphilic polymers. Therefore, the PEASBF has the potential for static marine antifouling applications.
Asunto(s)
Incrustaciones Biológicas , Canfanos , Polímeros , Incrustaciones Biológicas/prevención & control , Canfanos/química , Canfanos/farmacología , Polímeros/química , Polímeros/farmacología , Biopelículas/efectos de los fármacos , Animales , Pseudomonas/efectos de los fármacos , Betaína/química , Betaína/análogos & derivados , Betaína/farmacología , Albúmina Sérica Bovina/química , Diatomeas/efectos de los fármacos , Diatomeas/química , Tensoactivos/química , Tensoactivos/farmacología , Tensoactivos/síntesis química , Halogenación , Propiedades de SuperficieRESUMEN
Harmful algal bloom (HAB) is an unresolved existing problem worldwide. Here, we reported a novel algicidal bacterium, Pseudomonas fragi YB2, capable of lysing multiple algal species. To Chlorella vulgaris, YB2 exhibited a maximum algicidal rate of 95.02 % at 120 h. The uniqueness of YB2 lies in its ability to self-produce three algicidal compounds: 2-methyl-1, 3-cyclohexanedione (2-MECHD), N-phenyl-2-naphthylamine, and cyclo (Pro-Leu). The algicidal properties of 2-MECHD have not been previously reported. YB2 significantly affected the chloroplast and mitochondrion, thus decreasing in chlorophyll a by 4.74 times for 120 h and succinate dehydrogenase activity by 103 times for 36 h. These physiological damages disrupted reactive oxygen species and Ca2+ homeostasis at the cellular level, increasing cytosolic superoxide dismutase (23 %), catalase (35 %), and Ca2+ influx. Additionally, the disruption of Ca2+ homeostasis rarely reported in algicidal bacteria-algae interaction was observed using the non-invasive micro-test technology. We proposed a putative algicidal mechanism based on the algicidal outcomes and physiological algicidal effects and explored the potential of YB2 through an algicidal simulation test. Overall, this study is the first to report the algicidal bacterium P. fragi and identify a novel algicidal compound, 2-MECHD, providing new insights and a potent microbial resource for the biocontrol of HAB.
Asunto(s)
Chlorella vulgaris , Pseudomonas , Pseudomonas/metabolismo , Pseudomonas/efectos de los fármacos , Chlorella vulgaris/efectos de los fármacos , Chlorella vulgaris/metabolismo , Ciclohexanonas/toxicidad , Ciclohexanonas/química , Especies Reactivas de Oxígeno/metabolismo , Calcio/metabolismo , Clorofila A/metabolismoRESUMEN
The quantification of pesticide dissipation in agricultural soil is challenging. In this study, we investigated atrazine biodegradation in both liquid and soil experiments bioaugmented with distinct atrazine-degrading bacterial isolates. This was achieved by combining 14C-mineralisation assays and compound-specific isotope analysis of atrazine. In liquid experiments, the three bacterial isolates mineralised over 40% of atrazine, demonstrating their potential for extensive degradation. However, the kinetics of mineralisation and degradation varied among the isolates. Carbon stable isotope fractionation was similar for Pseudomonas isolates ADPT34 and ADP2T0, but slightly higher for Chelatobacter SR27. In soil experiments, atrazine primarily degraded into atrazine-desethyl, while atrazine-hydroxy was mainly observed in experiments with SR27. Atrazine mineralisation in soil by ADPT34 and SR27 exceeded 40%, whereas ADP2T0 exhibited a mineralisation rate of 10%. In experiments with ADPT34 and SR27, atrazine 14C-residues were predominantly found in the non-extractable fraction, whereas they accumulated in the extractable fraction in the experiment with ADP2T0. Compound-specific isotope analysis (CSIA) relies on changes of stable isotope ratios and holds potential to evaluate herbicide transformation in soil. CSIA of atrazine indicated atrazine biodegradation in water and solvent extractable soil fractions and varied between 29% and 52%, depending on the bacterial isolate. Despite atrazine degradation in both soil fractions, a significant portion of atrazine residues persisted, depending on the bacterial degrader, initial cell concentration, and mineralisation and degradation rates. Overall, our approach can aid in quantifying atrazine persistence and degradation in soil, and in optimizing bioaugmentation strategies for remediating soils contaminated with persistent herbicides.
Asunto(s)
Atrazina , Biodegradación Ambiental , Herbicidas , Microbiología del Suelo , Contaminantes del Suelo , Suelo , Atrazina/metabolismo , Contaminantes del Suelo/metabolismo , Contaminantes del Suelo/análisis , Herbicidas/metabolismo , Herbicidas/análisis , Suelo/química , Radioisótopos de Carbono , Cinética , Isótopos de Carbono , Bacterias/metabolismo , Pseudomonas/metabolismoRESUMEN
The sericulture industry suffers severe crop losses due to various silkworm diseases, necessitating the development of further technologies for rapid pathogen detection. Here, we report an all-in-one portable biosensor that combines conjugated gold nanoparticles (Au NPs) with an aptamer-based lateral flow assay (LFA) platform for the real-time analysis of Mammaliicoccus sp. and Pseudomonas sp. Our platform enables sample-to-answer naked eye detection within 5 min without any cross-reactivity with other representatives of the silkworm pathogenic bacterial group. This assay was based on the sandwich-type format using a bacteria-specific primary aptamer (Apt1) conjugated with 23 nm ± 1.27 nm Au NPs as a signal probe and another bacteria-specific secondary aptamer (Apt2)-coated nitrocellulose membrane as a capture probe. The hybridization between the signal probe and the capture probe in the presence of bacteria develops a red band in the test line, whose intensity is directly proportional to the bacterial concentration. Under the optimal experimental conditions, the visual limit of detection of the strip for Mammaliicoccus sp. and Pseudomonas sp. was 1.5 × 104 CFU/mL and 1.5 × 103 CFU/mL, respectively. Additionally, the performance of the LFA device was validated by using a colorimetric assay, and the results from the colorimetric assay are consistent with those obtained from the LFA. Our findings indicate that the developed point-of-care diagnostic device has significant potential for providing a cost-effective, scalable alternative for the rapid detection of silkworm pathogens.