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International Journal of Biological... Jun 2024This study determined the inhibitory mechanism as well as anti-biofilm activity of chlorogenic acid-grafted-chitosan (CS-g-CA) against Pseudomonas fluorescens (P....
This study determined the inhibitory mechanism as well as anti-biofilm activity of chlorogenic acid-grafted-chitosan (CS-g-CA) against Pseudomonas fluorescens (P. fluorescens) in terms of biofilm content, oxidative stress, quorum sensing and cyclic diguanosine monophosphate (c-di-GMP) concentration, and detected the changes in the expression levels of related genes by quantitative real-time PCR (qRT-PCR). Results indicated that treatment with sub-concentrations of CS-g-CA for P. fluorescens led to reduce the biofilm size of large colonies, decrease the content of biofilm and extracellular polymers, weaken the motility and adhesion of P. fluorescens. Moreover, CS-g-CA resulted in higher ROS levels, diminished catalase activity (CAT), and increased superoxide dismutase (SOD) in P. fluorescens. CS-g-CA reduced the production of quorum-sensing signaling molecules (AHLs) and the concentration of c-di-GMP in bacteria. Genes for flagellar synthesis (flgA), the resistance to stress (rpoS and hfq), and pde (phosphodiesterases that degrade c-di-GMP) were significantly down-regulated as determined by RT-PCR. Overall, CS-g-CA leads to the accumulation of ROS in bacteria via P. fluorescens environmental resistance genes and decreases the activity of enzymes in the bacterial antioxidant system, and interferes with the production and reception of quorum-sensing signaling molecules and the synthesis of c-di-GMP in P. fluorescens, which regulates the generation of biofilms.
PubMed: 38852716
DOI: 10.1016/j.ijbiomac.2024.133029 -
Microbiology Resource Announcements Jun 2024We provide the complete genome sequence for a novel bacteriophage named UNO-G1W1. This phage was isolated from a single ice cover sampling. The genome was sequenced on...
We provide the complete genome sequence for a novel bacteriophage named UNO-G1W1. This phage was isolated from a single ice cover sampling. The genome was sequenced on the Nanopore MinION, generated with the direct terminal repeat-phage-pipeline and polished with Illumina short reads. Sequence identity classifies the phage as an .
PubMed: 38847506
DOI: 10.1128/mra.00384-24 -
Ecology Letters Jun 2024Interspecific competition can hinder populations from evolutionarily adapting to abiotic environments, particularly by reducing population size and niche space; and...
Interspecific competition can hinder populations from evolutionarily adapting to abiotic environments, particularly by reducing population size and niche space; and feedback may arise between competitive ability and evolutionary adaptation. Here we studied populations of two model bacterial species, Escherichia coli and Pseudomonas fluorescens, that evolved in monocultures and cocultures for approximately 2400 generations at three temperatures. The two species showed a reversal in competitive dominance in cocultures along the temperature gradient. Populations from cocultures where they had been competitively dominant showed the same magnitude of fitness gain as those in monocultures. However, competitively inferior populations in cocultures showed limited abiotic adaptation compared with those in monocultures. The inferior populations in cocultures were also more likely to evolve weaker interspecific competitive ability, or go extinct. The possible competitive ability-adaptation feedback may have crucial consequences for population persistence.
Topics: Pseudomonas fluorescens; Escherichia coli; Biological Evolution; Adaptation, Physiological; Temperature
PubMed: 38844349
DOI: 10.1111/ele.14457 -
Ecotoxicology and Environmental Safety Jul 2024This study aimed to evaluate the effect of adding liquid extract of algae (Hypnea musciformis, Grateloupia acuminata, and Sargassum muticum) (HGS) and Magnesium oxide...
Synergistic effect of green synthesis magnesium oxide nanoparticles and seaweed extract on improving water quality, health benefits, and disease resistance in Nile tilapia.
This study aimed to evaluate the effect of adding liquid extract of algae (Hypnea musciformis, Grateloupia acuminata, and Sargassum muticum) (HGS) and Magnesium oxide nanoparticles (MgO NPs) using this extract to rear water of Oreochromis niloticus, on improving culture water indices, growth performance, digestive enzyme, hemato-biochemical characters, immune, antioxidative responses, and resistance after challenged by Aeromonas hydrophila with specific refer to the potential role of the mixture in vitro as resistance against three strains bacteria (Aeromonas sobria, Pseudomonas fluorescens, P. aeruginosa) and one parasite (Cichlidogyrus tilapia). The first group represented control, HGS0, whereas the other group, HGS5, HGS10, and HGS15 mL of liquid extract, as well as all groups with 7.5 μg mL MgO-NPs added to culture water of O. niloticus, for 60 days. Data showed that increasing levels at HGS 10 and HGS15 mL in to-culture water significantly enhanced growth-stimulating digestive enzyme activity and a significantly improved survival rate of O. niloticus after being challenged with A. hydrophila than in the control group. The total viability, coliform, fecal coliform count, and heavy metal in muscle partially decreased at HGS 10 and HGS15 mL than in the control group. Correspondingly, the highest positive effect on hemato-biochemical indices was noticed at levels HGS 10 and HGS15 mL. Fish noticed an improvement in immune and antioxidant indices compared to control groups partially at HGS 10 and HGS15 mL. Interestingly, fish cultured in rearing water with the mixture provided downregulated the related inflammatory genes (HSP70, TNF, IL-1β, and IL-8) partially at HGS15 mL. In vitro, the mixture showed positive efficiency as an antibacterial and partially antiparasitic at HGS 10 and HGS15 mL. This study proposes utilizing a mixture of (HGS) and (MgO-NPs) with optimum levels of 10-15 mL in cultured water to improve water indices, growth, health status, and increased resistance of O. niloticus against bacterial and parasitic infection.
Topics: Animals; Magnesium Oxide; Cichlids; Disease Resistance; Water Quality; Seaweed; Fish Diseases; Plant Extracts; Nanoparticles; Green Chemistry Technology; Metal Nanoparticles; Aeromonas hydrophila; Sargassum
PubMed: 38843743
DOI: 10.1016/j.ecoenv.2024.116522 -
BioRxiv : the Preprint Server For... May 2024are exposed to a variety of pathogenic and non-pathogenic bacteria species in their natural environment. Correspondingly, has evolved an ability to discern between...
are exposed to a variety of pathogenic and non-pathogenic bacteria species in their natural environment. Correspondingly, has evolved an ability to discern between nutritive and infectious bacterial food sources. Here we show that can learn to avoid the pathogenic bacteria (PF15), and that this learned avoidance behavior is passed on to progeny for four generations, as we previously demonstrated for (PA14) and , using similar mechanisms, including the involvement of both the TGF-β ligand DAF-7 and retrotransposon-encoded virus-like particles. PF15 small RNAs are both necessary and sufficient to induce this transgenerational avoidance behavior. Unlike PA14 or , PF15 does not use P11, Pv1, or a small RNA with homology for this avoidance; instead, an unrelated PF15 small RNA, Pfs1, that targets the Ephrin receptor gene is necessary and sufficient for learned avoidance, suggesting the evolution of yet another bacterial sRNA/ gene target pair involved in transgenerational inheritance of pathogen avoidance. As VAB-2 Ephrin receptor ligand and MACO-1 knockdown also induce PF15 avoidance, we have begun to understand the genetic pathway involved in small RNA targeted pathogenic avoidance. Moreover, these data show that axon guidance pathway genes (VAB-1 and VAB-2) have previously unknown adult roles in regulating neuronal function. may have evolved multiple bacterial specificity-encoded small RNA-dependent mechanisms to avoid different pathogenic bacteria species, thereby providing progeny with a survival advantage in a dynamic environment.
PubMed: 38826453
DOI: 10.1101/2024.05.23.595334 -
Microbial Cell Factories Jun 2024Syringic acid (SA) is a high-value natural compound with diverse biological activities and wide applications, commonly found in fruits, vegetables, and herbs. SA is...
BACKGROUND
Syringic acid (SA) is a high-value natural compound with diverse biological activities and wide applications, commonly found in fruits, vegetables, and herbs. SA is primarily produced through chemical synthesis, nonetheless, these chemical methods have many drawbacks, such as considerable equipment requirements, harsh reaction conditions, expensive catalysts, and numerous by-products. Therefore, in this study, a novel biotransformation route for SA production was designed and developed by using engineered whole cells.
RESULTS
An O-methyltransferase from Desulfuromonas acetoxidans (DesAOMT), which preferentially catalyzes a methyl transfer reaction on the meta-hydroxyl group of catechol analogues, was identified. The whole cells expressing DesAOMT can transform gallic acid (GA) into SA when S-adenosyl methionine (SAM) is used as a methyl donor. We constructed a multi-enzyme cascade reaction in Escherichia coli, containing an endogenous shikimate kinase (AroL) and a chorismate lyase (UbiC), along with a p-hydroxybenzoate hydroxylase mutant (PobA) from Pseudomonas fluorescens, and DesAOMT; SA was biosynthesized from shikimic acid (SHA) by using whole cells catalysis. The metabolic system of chassis cells also affected the efficiency of SA biosynthesis, blocking the chorismate metabolism pathway improved SA production. When the supply of the cofactor NADPH was optimized, the titer of SA reached 133 μM (26.2 mg/L).
CONCLUSION
Overall, we designed a multi-enzyme cascade in E. coli for SA biosynthesis by using resting or growing whole cells. This work identified an O-methyltransferase (DesAOMT), which can catalyze the methylation of GA to produce SA. The multi-enzyme cascade containing four enzymes expressed in an engineered E. coli for synthesizing of SA from SHA. The metabolic system of the strain and biotransformation conditions influenced catalytic efficiency. This study provides a new green route for SA biosynthesis.
Topics: Gallic Acid; Biocatalysis; Escherichia coli; Metabolic Engineering; Methyltransferases; Shikimic Acid; Pseudomonas fluorescens; Biotransformation
PubMed: 38824548
DOI: 10.1186/s12934-024-02441-x -
Archives of Microbiology May 2024The objective of this study was to investigate the effectiveness of a phage cocktail against Pseudomonas fluorescens group and its effect on the microbial, physical and...
The objective of this study was to investigate the effectiveness of a phage cocktail against Pseudomonas fluorescens group and its effect on the microbial, physical and chemical properties of raw milk during different storage conditions. A phage cocktail consisting of Pseudomonas fluorescens, Pseudomonas tolaasii, and Pseudomonas libanensis phages was prepared. As a result, reductions in fluorescent Pseudomonas counts of up to 3.44 log units for the storage at 4 °C and 2.38 log units for the storage at 25 °C were achieved. Following the phage application, it is found that there was no significant difference in the total mesophilic aerobic bacteria and Enterobacteriaceae counts. However, it was observed that the number of lactic acid bacteria was higher in phage-treated groups. The results also showed that pH values in the phage added groups were lower than the others and the highest titratable acidity was obtained only in the bacteria-inoculated group. As a future perspective, this study suggests that, while keeping the number of target microorganisms under control in the milk with the use of phages during storage, the microbiota and accordingly the quality parameters of the milk can be affected. This work contributes to the development of effective strategies for maintaining the quality and extending the shelf life of milk and dairy products.
Topics: Milk; Pseudomonas fluorescens; Animals; Pseudomonas Phages; Food Microbiology; Hydrogen-Ion Concentration; Bacteriophages
PubMed: 38806864
DOI: 10.1007/s00203-024-04008-1 -
Pharmaceutics May 2024In recent decades, ionic liquids (ILs) have garnered research interest for their noteworthy properties, such as thermal stability, low or no flammability, and negligible...
In recent decades, ionic liquids (ILs) have garnered research interest for their noteworthy properties, such as thermal stability, low or no flammability, and negligible vapour pressure. Moreover, their tunability offers limitless opportunities to design ILs with properties suitable for applications in many industrial fields. This study aims to synthetise two series of methylimidazolium ILs bearing long alkyl chain in their cations (C9, C10, C12, C14, C16, C18, C20) and with tetrafluoroborate (BF) and the 1,3-dimethyl-5-sulfoisophthalate (DMSIP) as counter ions. The ILs were characterised using H-NMR and MALDI-TOF, and their thermal behaviour was investigated through DSC and TGA. Additionally, the antimicrobial, anticancer, and cytotoxic activities of the ILs were analysed. Moreover, the most promising ILs were incorporated at different concentrations (0.5, 1, 5 wt%) into polyvinyl chloride (PVC) by solvent casting to obtain antimicrobial blend films. The thermal properties and stability of the resulting PVC/IL films, along with their hydrophobicity/hydrophilicity, IL surface distribution, and release, were studied using DSC and TGA, contact angle (CA), SEM, and UV-vis spectrometry, respectively. Furthermore, the antimicrobial and cytotoxic properties of blends were analysed. The in vitro results demonstrated that the antimicrobial and antitumor activities of pure ILs against t , , strains, and the breast cancer cell line (MCF7), respectively, were mainly dependent on their structure. These activities were higher in the series containing the BF anion and increased with the increase in the methylimidazolium cation alkyl chain length. However, the elongation of the alkyl chain beyond C16 induced a decrease in antimicrobial activity, indicating a cut-off effect. A similar trend was also observed in terms of in vitro biocompatibility. The loading of both the series of ILs into the PVC matrix did not affect the thermal stability of PVC blend films. However, their T decreased with increased IL concentration and alkyl chain length. Similarly, both the series of PVC/IL films became more hydrophilic with increasing IL concentration and alkyl chain. The loading of ILs at 5% concentration led to considerable IL accumulation on the blend film surfaces (as observed in SEM images) and, subsequently, their higher release. The biocompatibility assessment with healthy human dermal fibroblast (HDF) cells and the investigation of antitumoral properties unveiled promising pharmacological characteristics. These findings provide strong support for the potential utilisation of ILs in biomedical applications, especially in the context of cancer therapy and as antibacterial agents to address the challenge of antibiotic resistance. Furthermore, the unique properties of the PVC/IL films make them versatile materials for advancing healthcare technologies, from drug delivery to tissue engineering and antimicrobial coatings to diagnostic devices.
PubMed: 38794304
DOI: 10.3390/pharmaceutics16050642 -
Microorganisms May 2024Lactoperoxidase (LP) is an important enzyme of the salivary and mammary glands. It has been proven to increase the shelf life of raw milk by inhibiting the growth of...
Lactoperoxidase (LP) is an important enzyme of the salivary and mammary glands. It has been proven to increase the shelf life of raw milk by inhibiting the growth of bacteria, especially , , , and spp. The aim of this work was to verify the use of LP to extend the shelf life of meat products. In vitro experiments showed inhibitory effects on the selected bacteria ( (ATCC 33090), (CP054440.1), and (ATCC 13525) due to a prolongation of the lag phase of growth curves. A lower increase in viable counts ( < 0.05) was also found by testing pork cubes' surface treated with LP solution (5%) + and stored for 7 days at 15 °C. LP has also been studied at concentrations of 0.25 and 0.50% in meat products (pork ham and pâté) during refrigerated storage (4 °C for 28 days). Lower viable counts were observed throughout the storage experiment, especially for 0.50% LP ( < 0.05). Meat products containing LP also showed lower levels of oxidation (MAD) ( < 0.05). According to these results, LP could extend the shelf life of a wider range of products.
PubMed: 38792839
DOI: 10.3390/microorganisms12051010 -
Microorganisms May 2024To optimize the application of plant growth-promoting rhizobacteria (PGPR) in field trials, tracking methods are needed to assess their shelf life and to determine the...
To optimize the application of plant growth-promoting rhizobacteria (PGPR) in field trials, tracking methods are needed to assess their shelf life and to determine the elements affecting their effectiveness and their interactions with plants and native soil microbiota. This work developed a real-time PCR (qtPCR) method which traces and quantifies bacteria when added as microbial consortia, including five PGPR species: , , , , and Through a literature search and in silico sequence analyses, a set of primer pairs which selectively tag three bacterial species (, and ) was retrieved. The primers were used to trace these microbial species in a field trial in which the consortium was tested as a biostimulant on two wheat varieties, in combination with biochar and the mycorrhizal fungus . The qtPCR assay demonstrated that the targeted bacteria had colonized and grown into the soil, reaching a maximum of growth between 15 and 20 days after inoculum. The results also showed biochar had a positive effect on PGPR growth. In conclusion, qtPCR was once more an effective method to trace the fate of supplied bacterial species in the consortium when used as a cargo system for their delivery.
PubMed: 38792831
DOI: 10.3390/microorganisms12051002