ACTA AGRICULTURAE SCANDINAVICA SECTION B-SOIL AND PLANT SCIENCE
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2018
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IF 0.894
Yujie Yin,Pei’en Ni,Bohan Deng,Shiping Wang,Wenping Xu,Dapeng Wang
Purpose: Pseudomonas syringae pv. actinidiae causes bacterial canker of kiwifruit and is responsible for severe economic losses and emergence of drug-resistant bacteria. Bacteriophages are viruses that infect target bacterial hosts and may be the best strategy to prevent and control kiwifruit canker disease. The objective of this experiment was to monitor the prevalence of Pseudomonas syringae pv. actinidiae and provide insight for the use of phages in biological control.Materials and methods: In this study, 52 strains of Pseudomonas syringae pv. actinidiae were isolated from 68 stem samples of kiwi plant (cv. Hongyang & Jinkui). Following polymerase chain reaction (PCR) analysis, 15 isolates belonging to biovar 3 were identified, one of which was named XWY0007 and used as the target strain to isolate the phages. Thirty-six phages were isolated and purified from a total of 51 surface water samples collected in Shanghai. All phages were identified by transmission electron microscopy (TEM) and their host ranges were evaluated. Three phages, designated φXWY0013, φXWY0014 and φXWY0026 were selected and further characterised using one-step growth curve and stability at different temperatures and pH.Results and conclusions: The isolated phages are promising for use as antimicrobials against bacterial canker in kiwi. This report is regarding Pseudomonas syringae pv. actinidiae and its phages from major areas of kiwifruit cultivation.
研究领域:
植物病理学
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微生物学
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
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2022
·Vol. 30
·期 10
·28227-28237
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IF 5.19
Liu Huan-Huan,Yang Lei,Guo Lin-Kai,Tu Li-Xin,Li Xiao-Tong,Wang Jia,Ren Yong-Xiang
The occurrence of metal oxide nanoparticles (NPs) in wastewater treatment plants (WWTPs) has raised great concerns about their adverse impacts on nitrification performance. In this study, a heterotrophic nitrifying bacterium Pseudomonas putida strain NP5 showed strong resistance against TiO 2 and NiO NPs. Under 5–50 mg/L NP stress, cell viability was still normal, and the final nutrient removal rates, always higher than 80%, were slightly inhibited. Correspondingly, the PO 4 3− -P removal rates were almost the same as those observed in the control test. Although the enzyme assay demonstrated ammonia monooxygenase and hydroxylamine oxidoreductase activities markedly decreased caused by increased reactive oxygen species (ROS) level under 50 mg/L NPs stress. The total antioxidant capability of NP5 could eliminate excess ROS to maintain a balance between oxidants and antioxidants. Besides, in response to the escalating burden of NPs, strain NP5 tended to secrete more extracellular polymeric substances (EPS), which could protect cell from being damaged by binding to ions and coating. Thus, the strong NP resistance of NP5 would help to overcome the vulnerability of the nitrification process in WWTPs.
研究领域:
环境微生物学
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纳米毒理学
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污水处理
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微生物生理学
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ENVIRONMENTAL TECHNOLOGY
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2018
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IF 1.666
Shufeng Liu,Ming Wang,Tingting Li,Qian Chen
The cytotoxicity of titanium dioxide nanoparticles (TiO2 NPs) to microorganisms has attracted great attention over the past few decades. As an important participator in the nitrogen cycle, aerobic denitrifiers have been proven to be negatively affected by TiO2 NPs, but the mechanism of this effect remains unclear. In this study, the bacteria-nanoparticle interaction was investigated by exposing an aerobic denitrifier, Pseudomonas stutzeri PCN-1 to different concentrations of TiO2 NPs at the dark condition, in order to investigate the cytotoxicity mechanism. The results illustrated that aerobic denitrification was inhibited at different TiO2 NPs concentrations from 1 to 128 mg/L, accompanied by the postponement of nitrate reduction and the accumulations of nitrite and nitrous oxide. But this inhibitory effect was mitigated with increasing TiO2 NPs concentrations. Further studies revealed that expressions of aerobic denitrification genes were also inhibited with the presence of TiO2 NPs, and the inhibition effect on napA and nirS genes was more significant than that on nosZ and cnorB, which might directly bring about the delayed nitrate reduction and hindered nitrite transfer. Moreover, the decreased toxicities at higher TiO2 NPs concentrations could be attributed to the formation of larger aggregates (>1000 nm), which greatly reduced the chance for direct interactions between NPs and bacterial membranes, as well as the interruption of denitrifying genes expressions. These findings were meaningful for the formation of deep insights into the mechanism of TiO2 NPs cytotoxicity as well as the development of strategies to control the negative effect of nanoparticles in the environment.Aerobic denitrification characteristics of strain PCN-1 under different carbon sources.
研究领域:
环境科学
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微生物学
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JOURNAL OF DAIRY SCIENCE
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2023
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IF 3.5
Lei Yuan,Yanhe Zhang,Zizhuo Mi,Xiangfeng Zheng,Shuo Wang,Huaxiang Li,Zhenquan Yang
ABSTRACT Biofilm formation is usually affected by many environmental factors including divalent cations. The purpose of the current work was to analyze how calcium (Ca 2+ ) affects the biofilm formation of dairy Pseudomonas fluorescens isolates by investigating their growth, swarming motility, biofilm-forming capacity, EPS production, and biofilm structures. Moreover, the regulation mechanism of Ca 2+ involved in its biofilm formation was explored through RNA-sequencing analysis. This work revealed that supplementation of 5, 10, 15, and 20 mM Ca 2+ significantly reduced the swarming motility of P. fluorescens strains (P.F 2 , P.F 4 , and P.F 17 ), but the biofilm-forming ability and polysaccharide production were increased after the supplementation of 5 and 10 mM Ca 2+ . By the supplementation of Ca 2+ , complex structures with more cell clusters glued together in P. fluorescens P.F 4 biofilms were confirmed by scanning electron microscopy, and increased biomass and coverage of P. fluorescens P.F 4 biofilms were observed by confocal laser scanning microscopy. In addition, RNA-sequencing results showed that P. fluorescens P.F 4 showed a transcriptional response to the supplementation of 10 mM Ca 2+ , and a total of 137 genes were significantly expressed. The differential genes were represented in 4 upregulated KEGG pathways (nonribosomal peptide structures, quorum sensing, biosynthesis of siderophore group nonribosomal peptides, and phenylalanine metabolism), and 4 downregulated KEGG pathways (flagellar assembly, amino sugar and nucleotide sugar metabolism, nitrotoluene degradation, and cationic antimicrobial peptide (CAMP) resistance). The results indicate that Ca 2+ might serve as an enhancer to substantially trigger the biofilm formation of dairy P. fluorescens isolates in the dairy industry.
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Frontiers in Microbiology
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2026
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IF 5.8
Chaoyue Yang,Zhenyu Liu,Xiaoya Peng,Li Zhou,Zhixiong Xie,Jun Huang,Wenhui Jiang,Songtao Ai,Fang Peng
Polar warming is expected to release and redistribute psychrophilic microorganisms, thereby increasing their likelihood of encountering warmer environments and potential hosts. However, it remains uncertain whether psychrophilic polar bacteria maintain pathogenic properties relevant to mammalian hosts during such transitions. Here, we investigated two hemolytic Antarctic Pseudomonas isolates, 3S6 and NS21, assigned to P. antarctica and P. yamanorum, respectively. Both isolates exhibited hemolytic activity, biofilm formation, and siderophore production, although these phenotypes were weaker than those of P. aeruginosa. Functional analyses indicated that their cell-associated hemolytic activity was dependent on the ExlBA two-partner secretion system (TPS), in which the outer-membrane transporter ExlB secretes the pore-forming cytotoxin ExlA: deletion of exlB abolished hemolysis, whereas genetic complementation restored this phenotype, and this activity was temperature-sensitive, consistent with repression of ExlBA expression under elevated temperatures. Temperature elevation from 20 °C to 28 °C reduced hemolytic activity, exlBA transcription, and intracellular cAMP levels, while strongly inducing cpdA, implicating a CpdA-cAMP/Vfr-associated regulatory mechanism. Elevated temperature also triggered a transition from a motile to a biofilm-associated lifestyle in strain 3S6, potentially reflecting adaptive resource allocation toward survival rather than virulence under thermal stress. Under host-relevant conditions, both isolates caused ExlBA-dependent membrane damage in mammalian cells and shortened Caenorhabditis elegans survival. In mice, they caused transient bloodstream invasion and acute lung inflammation without mortality or sustained colonization. Collectively, these findings indicate that psychrophilic hemolytic polar Pseudomonas possess restricted, temperature-responsive host-damaging capacity under exposure conditions associated with environmental warming.
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CATALYSIS LETTERS
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2020
·Vol. 150
·期 7
·1841-1848
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IF 2.482
Wu Ting-Ting,Zhao Xiang-Jie,Yang Rong-Ling,Bilal Muhammad,Wang Zhao-Yu,Luo Hong-Zhen,Xu Ning-Ning,Nie Ze-Kun
In this study, lyophilized Pseudomonas aeruginosa based whole-cell biocatalyst was used in the highly efficient and regioselective acylation of helicid with fatty acid vinyl esters in organic solvents. P. aeruginosa whole-cell catalyst showed high biomass and biocatalytic performance using 0.1% (w/v) soybean oil and 0.2% (w/v) tryptone as the carbon and nitrogen source, respectively. The biomass (0.72 g/L) cultivated for 36 h under the optimized conditions was 2-folds higher than that obtained by the use of the initial conditions (0.36 g/L). In addition, the optimized medium was found to be suitable for P. aeruginosa cultured in 3.5-L scale fermentation with high biomass (0.71 g/L) obtained at 24 h. Besides, a high substrate conversion efficiency (ranged from 92 to 99%) and excellent regioselectivity (99%) was achieved when P. aeruginosa whole-cell biocatalyst was applied to synthesize an array of 6′-esters of helicid. The reaction rate varies with varying acyl donors because of their differential interactions with the catalytic site of the enzyme from the whole cells of P. aeruginosa . Taken together, P. aeruginosa whole-cell catalyst obtained using optimal culture medium manifest a promising and highly-regioselective alternative to purified enzymes for the regioselective formation of 6′-esters derivatives of helicid in non-aqueous solvents. Graphic Abstract
研究领域:
生物化学
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酶工程
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工业微生物学
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2012
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IF 2.823
Jian-Dong Cui,Ji Qing Qiu
Curdlan is a microbial polysaccharide composed exclusively of β-(1,3)-linked glucose residues. Until now only bacteria belonging to the Alcaligenes and Agrobacterium species have been reported to produce Curdlan. In this study, a bacterium capable of producing extracellular Curdlan, identified as Pseudomonas sp. on the basis of 16S rDNA gene sequencing, was isolated from soil samples. From the HPLC, permethylation linkage analysis, 13C NMR, and FT-IR analytical data, the polysaccharide consisted exclusively of glucose; the most prominent sugar was 1,3-linked glucose, and most glycosidic bonds joining these sugar residues were of the β-type. This also supported that the exopolysaccharide produced by Pseudomonas sp. was actually Curdlan. In addition, the Pseudomonas sp. was studied for the production of Curdlan by conventional “one-factor-at-a-time technique” and response surface methodology (RSM). It was observed that glucose and yeast extract were the most suitable carbon source and nitrogen source for Curdlan production, respectively. By using RSM, Curdlan production was increased significantly by 188%, from 1.25 to 2.35 g/L, when the strain was cultivated in the optimal condition developed by RSM, and the highest Curdlan production rate of 0.81 g/(L h) was obtained. To the best of the authors' knowledge, this is the first report on Curdlan production by Pseudomonas sp.
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INTERNATIONAL JOURNAL OF PHARMACEUTICS
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2016
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IF 3.994
Y. Long,Z. Li,Q. Bi,C. Deng,Z. Chen,S. Bhattachayya,C. Li
Considering outburst of various infectious diseases globally, nanoparticle assisted targeted drug delivery has emerged as a promising strategy that can enhance the therapeutic efficacy and minimize the undesirable side effects of an antimicrobial agents. Molecular imprinting is a newly developed strategy that can synthesize a drug carrier with highly stable ligand-like ‘cavity’, may serve as a new platform of ligand-free targeted drug delivery systems. In this study, we use the amphiphilic lipopolysaccharides, derived from Pseudomonas aeruginosa as imprinting template and obtained an evenly distributed sub-40 nm polymeric nanoparticles by using inverse emulsion method. These molecularly imprinted nanoparticles (MIPNPs) showed specific binding to the lipopolysaccharide as determined by fluorescence polarization and microscale thermophoresis. MIPNPs showed selective recognition of target bacteria as detected by flow cytometry. Additionally, MIPNPs exhibited the in vivo targeting capabilities in both the keratitis model and meningitis model. Moreover, the photosensitizer methylene blue-loaded MIPNPs presented significantly strong inhibition of bacterial Growth, compared to non-imprinted controls for in vitro model of the photodynamic therapy. Our study shows an attempt to design a magic bullet by molecular imprinting that may provide a novel approach to generate synthetic carrier for targeting pathogen and treatment for a variety of infectious human diseases.
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Frontiers in Microbiology
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2024
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IF 4
Liu Chang,Cui Chenxuan,Tan Xiaoxin,Miao Junjie,Wang Wei,Ren Han,Wu Hua,Zheng Cuiying,Ren Huan,Kang Weijun
The emergence of multidrug-resistant Pseudomonas aeruginosa isolates is a growing concern for public health, necessitating new therapeutic strategies. Gallium nitrate [Ga(NO3)3], a medication for cancer-related hypercalcemia, has attracted great attention due to its ability to inhibit P. aeruginosa growth and biofilm formation by disrupting iron metabolism. However, the antibacterial efficacy of Ga(NO3)3 is not always satisfactory. It is imperative to investigate the factors that affect the bactericidal effects of Ga(NO3)3 and to identify new ways to enhance its efficacy. This study focused on the impact of pH on P. aeruginosa resistance to Ga(NO3)3, along with the underlying mechanism. The results indicate that acidic conditions could increase the effectiveness of Ga(NO3)3 against P. aeruginosa by promoting the production of pyochelin and gallium uptake. Subsequently, using glutamic acid, a clinically compatible acidic amino acid, the pH was significantly lowered and enhanced the bactericidal and inhibitory efficacy of Ga(NO3)3 against biofilm formation by P. aeruginosa, including a reference strain PA14 and several multidrug-resistant clinical isolates. Furthermore, we used an abscess mouse model to evaluate this combination in vivo; the results show that the combination of glutamic acid and Ga(NO3)3 significantly improved P. aeruginosa clearance. Overall, the present study demonstrates that acidic conditions can increase the sensitivity of P. aeruginosa to Ga(NO3)3. Combining glutamic acid and Ga(NO3)3 is a potential strategy for the treatment of P. aeruginosa infections.
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FOOD CONTROL
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2025
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IF 6.3
Chanchiang Liang,Siyang Chen,Wenxiu Zhu,Hanzheng Dou,Xiaodong Xia
The antimicrobial efficacy of punicalagin against foodborne pathogens has been extensively studied, yet its impact on spoilage microorganisms remains poorly characterized. This study aimed to evaluate punicalagin's inhibitory effects on Pseudomonas fluorescens and explore its potential application in tilapia preservation. Growth curve analysis showend that punicalagin effetively inhibited the growth of Pseudomonas fluorescens . In addition, punicalagin triggered intracellular potassium ion efflux and leakage of nucleic acids and protein. Scanning electron microscopy revealed compromised cell membrane integrity after punicalagin treatment. Furthermore, punicalagin exposure reduced intracellular ATP levels and elevated reactive oxygen species accumulation. Concurrently, it effectively suppressed biofilm formation and destroyed preformed biofilms. In tilapia spiked with Pseudomonas fluorescens , punicalagin markedly attenuated spoilage progression, as evidenced by diminished protein degradation and lipid oxidation. These collective findings indicate that punicalagin exhibit antimicrobial and anti-biofilm activities against Pseudomonas fluorescens , highlighting its potential as a natural preservative for aquatic products.
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Frontiers in Pharmacology
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2026
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IF 5.4
YaTong Zhang,Xuelin Sun,HuiBo Li,DanDan Li,Caiyuan Yu,Bin Zhao,YingChen Zhou,Yi Zhun Zhu,Rongsheng Zhao
Introduction Antibiotic resistance has become a global health crisis, driving the urgent need for novel antibacterial strategies. Antimicrobial peptides (AMPs) have emerged as promising therapeutic candidates due to their broad-spectrum activity and low propensity for resistance development. However, conventional discovery approaches remain time-consuming and inefficient for large-scale screening. Methods In this study, we developed an integrated prediction framework that combines deep learning with classical machine learning methods to enable rapid and accurate identification of AMPs. The model was applied to screen over 250,000 artificially generated peptide sequences. Candidate peptides were selected based on physicochemical descriptors and activity-associated features, followed by solid-phase synthesis and minimum inhibitory concentration assays against Pseudomonas aeruginosa. Mechanistic investigations were conducted using scanning electron microscopy to visualize membrane damage, molecular dynamics simulations to probe peptide-membrane interactions, and transcriptomic profiling to assess bacterial stress responses and metabolic pathway alterations. Results Ten promising antibacterial candidates were successfully identified and experimentally validated. All selected peptides exhibited measurable activity against P. aeruginosa, with several showing potent inhibitory effects. Microscopic and simulation analyses confirmed that the peptides exert their antibacterial effects primarily through membrane disruption. Transcriptomic data further revealed that these peptides interfere with key metabolic pathways and activate bacterial stress response systems. Discussion Our findings demonstrate that the integrated deep learning-machine learning pipeline offers an efficient and reliable approach for large-scale AMP discovery. The mechanistic insights gained from this study not only validate the predicted candidates but also provide a foundation for rational optimization of peptide-based therapeutics. This comprehensive strategy holds promise for accelerating the development of next-generation alternatives to conventional antibiotics.
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APPLIED AND ENVIRONMENTAL MICROBIOLOGY
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2021
·Vol. 87
·期 5
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IF 4.792
Shanshan Chen,Xianyue Jing,Yongliang Yan,Shaofu Huang,Xing Liu,Piao Chen,Shungui Zhou
Diazotrophs can produce bioavailable nitrogen from inert N2 gas by bioelectrochemical nitrogen fixation (e-BNF), which is emerging as an energy-saving and highly selective strategy for agriculture and industry. However, current e-BNF technology is impeded by requirements for NH4+ assimilation inhibitors to facilitate intracellular ammonia secretion and precious metal catalysts to generate H2 as the energy-carrying intermediate. Here, we initially demonstrate inhibitor- and catalystless extracellular NH4+ production by the diazotroph Pseudomonas stutzeri A1501 using an electrode as the sole electron donor. Multiple lines of evidence revealed that P. stutzeri produced 2.32 ± 0.25 mg/liter extracellular NH4+ at a poised potential of −0.3 V (versus standard hydrogen electrode [SHE]) without the addition of inhibitors or expensive catalysts. The electron uptake mechanism was attributed to the endogenous electron shuttle phenazine-1-carboxylic acid, which was excreted by P. stutzeri and mediated electron transfer from electrodes into cells to directly drive N2 fixation. The faradaic efficiency was 20% ± 3%, which was 2 to 4 times that of previous e-BNF attempts using the H2-mediated pathway. This study reports a diazotroph capable of producing secretable NH4+ via extracellular electron uptake, which has important implications for optimizing the performance of e-BNF systems and exploring the novel nitrogen-fixing mode of syntrophic microbial communities in the natural environment.IMPORTANCE Ammonia greatly affects global ecology, agriculture, and the food industry. Diazotrophs with an enhanced capacity of extracellular NH4+ excretion have been proven to be more beneficial to the growth of microalgae and plants, whereas most previously reported diazotrophs produce intracellular organic nitrogen in the absence of chemical suppression and genetic manipulation. Here, we demonstrate that Pseudomonas stutzeri A1501 is capable of extracellular NH4+ production without chemical suppression or genetic manipulation when the extracellular electrode is used as the sole electron donor. We also reveal the electron uptake pathway from the extracellular electron-donating partner to P. stutzeri A1501 via redox electron shuttle phenazines. Since both P. stutzeri A1501 and potential electron-donating partners (such as electroactive microbes and natural semiconductor minerals) are abundant in diverse soils and sediments, P. stutzeri A1501 has broader implications on the improvement of nitrogen fertilization in the natural environment.
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