Journal of Environmental Chemical Engineering
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2024
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IF 7.4
Zheng Qi,Chunguang Liu
Characterizing the metabolic network and dynamics of Viable But Nonculturable (VBNC) bacteria is crucial for their identification and control. In this study, single-cell Raman spectroscopy was used to explore the metabolic intricacies of VBNC P. aeruginosa induced by chlorine disinfection over 24 h. VBNC P. aeruginosa exhibited significant reductions of 75.98 %, 84.26 % and 81.07 % in carbohydrate, protein and nucleic acid Raman peaks, signaling decreased metabolic activity in these crucial components. Intriguingly, lipid metabolism in VBNC P. aeruginosa remained robust, indicating a potential adaptation to environmental stress. Furthermore, this study analyzed Raman characteristic peaks to examine metabolic conversion in these bacteria. VBNC P. aeruginosa displayed distinct phase-specific metabolic conversion patterns compared to culturable ones. These findings shed light on the temporal dynamics of metabolic processes, such as lipid-carbohydrate conversion, which appeared to be ongoing throughout the incubation period in VBNC P. aeruginosa . Compared to the culturable state, VBNC P. aeruginosa exhibited reduced isotopic assimilation rates for carbon, nitrogen and hydrogen by 40.57 %, 44.62 % and 39.45 %, indicating decreased substrate uptake for biomolecular synthesis. Additionally, the metabolic heterogeneity index of the VBNC bacterial population increased by 37.28 %, with this heterogeneity displaying a progressive increase with the duration of the culture. This observation suggests VBNC P. aeruginosa differentiation into distinct subpopulations, believed crucial for survival in challenging environments. These findings reveal the metabolic dynamics of VBNC state bacteria, providing insights into their adaptive strategies and implications for environmental health risk assessment and precise control technologies.
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Environmental Science-Processes & Impacts
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2024
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IF 4.3
Caihong Wang,Qiao Ma,Jiaxin Zhang,Nan Meng,Dan Xu
Benzalkonium chloride (BAC) is a disinfectant with broad-spectrum antibacterial properties, yet despite its widespread use and detection in the environments, the effects of BAC exposure on microorganisms remain poorly documented. Herein, the impacts of BAC on a Pseudomonas aeruginosa strain Jade-X were systematically investigated. The results demonstrated that the minimum inhibitory concentration (MIC) of BAC against strain Jade-X was 64 mg/L. Exposure to BAC concentrations of 8, 16, 32, and 64 mg/L significantly augmented biofilm formation by 2.03-, 2.43-, 2.96-, and 2.56-fold respectively. The swimming and twitching abilities, along with the pyocyanin production, were inhibited. Consistently, quantitative reverse transcription PCR assays revealed significant downregulation of genes related to flagellate- and pili-mediated motilities (flgD, flgE, pilB, pilQ, and motB), as well as phzA and phzB genes involved in pyocyanin production. The results of disk diffusion and MIC assays demonstrated that BAC decreased the antibiotic susceptibility of ciprofloxacin, levofloxacin, norfloxacin, and tetracycline. Conversely, an opposite trend was observed for polymyxin B and ceftriaxone. Genomic analysis revealed that strain Jade-X harbored eleven resistance-nodulation-cell division efflux pumps, with mexCD-oprJ exhibiting significant upregulation while mexEF-oprN and mexGHI-opmD were downregulated. In addition, the quorum sensing-related regulators LasR and RhlR were also suppressed, implying that BAC might modulate the physiological and biochemical behaviors of strain Jade-X by attenuating the quorum sensing system. This study enhances our understanding of interactions between BAC and P. aeruginosa, providing valuable insights to guide the regulation and rational use of BAC.
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Phytopathology Research
·
2022
·Vol. 4
·期 1
·1-12
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IF 3.955
Jiang Long,Xiang Shunyu,Lv Xing,Wang Xiaoyan,Li Fengwei,Liu Weina,Liu Changyun,Ran Mao,Huang Jin,Xu Xiaohong,Ma Xiaozhou,Jin Yabo,Sun Xianchao
Silver (Ag)-containing agents or materials are widely used today in plant protection for their antimicrobial activity. In view of the superior inhibitory ability of biosynthesized (aldehyde-modified sodium alginate based) silver nanoparticles (AgNPs) against plant pathogenic fungi in our previous research, here we explored the antagonistic effect of biosynthesized AgNPs on plant pathogenic bacteria and the underlying mechanism. We selected Pseudomonas syringae pv. tabaci , the causal agent of tobacco wildfire disease, as the target and found that 1.2 μg/mL biosynthesized AgNPs completely inhibited the growth of P. syringae pv. tabaci in vitro and in vivo by partly destroying the cell membrane structure of the pathogen, resulting in cytoplasmic leakage. Moreover, Nicotiana benthamiana treated with 1.2 μg/mL biosynthesized AgNPs exhibited a significant upregulation of nonexpressor of pathogenesis-related genes 1 ( NPR1 ) and pathogenesis-related gene 2 ( PR2 ), the typical markers of the salicylic acid (SA)-mediated defense system, and an increase in peroxidase (POD) and polyphenol oxidase (PPO) activities as well as the production of reactive oxygen species (ROS). Furthermore, biosynthesized AgNPs treatment increased the chlorophyll content and dry weight of N. benthamiana . Overall, we demonstrated that biosynthesized AgNPs at a low concentration have high inhibitory effect on the pathogen causing tobacco wildfire disease by destroying bacterial cell membrane and inducing defense resistance in host plant. These results lay a theoretical foundation for further application of biosynthesized AgNPs in the control of plant bacterial diseases.
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Journal of Water Process Engineering
·
2026
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IF 6.6
Yize Liu,Chuanzhou Liang,Ruizhuo Lu,Zhe Liu,Xiongbo Zhan,Zhongxiong Zhou,Lin Liu,Minhua He,Bolin Li,Zhiyu Wei
Sulfamethoxazole (SMX)-degrading bacteria have been isolated previously but were rarely applied into realistic wastewater due to poor colonization and instability. In this study, an efficient SMX-degrading bacteria consortium, dominated by Pseudomonas , was enriched from activated sludge and systematically evaluated for accelerated immobilization and application in the treatment of realistic municipal wastewater. The results showed that co-substrate addition markedly enhanced consortium growth and SMX degradation. Co-substrate type further governed immobilization: glucose accelerated biofilm formation on raw carriers, whereas sucrose favored planktonic growth and required chitosan-modified electrophilic carriers for effective immobilization. Co-substrate-assisted immobilization shortened the period from over 40 d to <10 d. Moreover, the immobilized consortia exhibited a remarkably SMX degradation efficiency with ∼3 h half-life, which was strongly correlated with total attached consortium DNA ( r = 0.988). The immobilized consortia achieved stable SMX removal (>99.8%) over 30 d of cyclic operation in realistic municipal influent and effluent wastewater, respectively, proving its applicability as bio-augmentation in secondary and polishing treatment for SMX. Microbial community analysis revealed persistent Pseudomonas dominance with adaptive diversification driven by co-substrate regime, carrier type, and wastewater conditions. Overall, this study highlights rational co-substrate selection and carrier design as key determinants for efficient immobilization and long-term performance of slow-growing antibiotic-degrading consortia, providing a scalable strategy for sulfonamide antibiotics removal in wastewater treatment systems.
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JOURNAL OF MICROBIOLOGY AND BIOTECHNOLOGY
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2026
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IF 3.4
Yuechen Xu,Lingyun Wei
Early and accurate detection of Pseudomonas aeruginosa ( P. aeruginosa ) is critically important in perioperative care to prevent severe healthcare-associated infections and guide timely antimicrobial intervention. Herein, we report a novel biosensing strategy for sensitive and label-free detection of P. aeruginosa by integrating F23 aptamer-mediated target recognition, garland rolling circle amplification (RCA)-triggered self-priming extension, and SYBR Green I (SG-I)-based fluorescence readout. The capture probe, comprising the F23 aptamer and a primer strand immobilized on magnetic nanoparticles, specifically recognizes P. aeruginosa and releases the primer to initiate dumbbell probe circularization and subsequent RCA. The resulting RCA products are cleaved by a nicking endonuclease to generate fragmented DNA, which then hybridizes with a hairpin probe to prime cyclic self-extension reactions, producing abundant double-stranded DNA for SG-I intercalation and fluorescence enhancement. Under optimized conditions, the proposed method achieves a detection limit as low as 2.3 CFU/mL with a wide linear range from 10 to 10 6 CFU/mL. The assay exhibits excellent specificity against non-target bacteria, robust stability during storage, and satisfactory anti-interference capability in complex clinical matrices. Validation using clinical samples demonstrates excellent agreement with the gold-standard colony counting method while reducing the assay time to less than 2.5 h without requiring nucleic acid extraction or thermal cycling. With its label-free design, isothermal amplification, and operational simplicity, this strategy holds great promise for point-of-care testing in perioperative settings and can be readily adapted for detecting other pathogens by substituting the corresponding aptamer.
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JOURNAL OF APPLIED MICROBIOLOGY
·
2025
·Vol. 136
·期 12
·
IF 3.2
Wang Wei,Jiang Kaichong,Zhou Yafei,Zhou Rui,Huang Wenjun,Huang Yinong
BackgroundMultidrug-resistant (MDR) Pseudomonas aeruginosa poses major therapeutic challenges due to biofilm-associated tolerance and limited antibiotic efficacy. Lipophilic diterpenoids from Salvia miltiorrhiza (Danshen) have reported antimicrobial potential, but their effects on P. aeruginosa biofilm phenotypes, motility, and antibiotic susceptibility remain poorly defined.Methods and resultsFive Danshen-derived compounds were tested for antibacterial activity, biofilm modulation, and motility inhibition in P. aeruginosa PAO1 and two MDR clinical isolates (designated XCH-MDR-01 and XCH-MDR-02). Antibacterial activity was negligible (MIC > 256 µmol L−1). Dihydrotanshinone I and tanshinone I enhanced PAO1 biofilm formation (20%–30%) but inhibited biofilm formation in MDR isolates (40%–50%) and disrupted established biofilms (50%–60% at 50 µmol L−1). Confocal microscopy confirmed reduced biofilm density and altered architecture in MDR isolates, contrasting with enhanced biofilms in PAO1. Motility was suppressed in MDR isolates but unaffected in PAO1. qPCR showed strain-specific regulation of wspR and pslA, with upregulation in PAO1 (2–3-fold) and downregulation (∼50%) in XCH-MDR-01. Co-treatment with dihydrotanshinone I or tanshinone I reduced ceftazidime MICs by 4–8-fold in MDR isolates.ConclusionsDanshen-derived diterpenoids exert strain-specific effects on P. aeruginosa biofilm formation and motility, and selectively potentiate ceftazidime activity against MDR isolates.
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LANGMUIR
·
2026
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IF 4.4
Yudan Chai,Bin Wang,Jun Xu,Jian Zhang
Microbial lipases are versatile biocatalysts that are essential for hydrolyzing ester bonds in triglycerides. Among these enzymes, Pseudomonas cepacia lipase (PCL) possesses a canonical lid domain, whereas Candida antarctica lipase B (CALB) features a rigid lid-like structure. Understanding how these different structures catalyze mechanisms differently at the interface is crucial. Experimental assays demonstrated high activity for both enzymes in aqueous systems, but CALB exhibited lower activity than PCL in biphasic water–organic solvent systems. Molecular dynamics simulations were employed to investigate the conformational dynamics and interfacial interactions. The results reveal that the PCL undergoes polarity-induced conformational changes leading to channel shortening and bottleneck widening, thereby facilitating substrate access. In contrast, CALB retains a rigid architecture with fixed distances between the lid-like region and the catalytic triad, thereby limiting interfacial adaptability. PCL further employs a lid-mediated adsorption mechanism that enhances interfacial binding and exposes hydrophobic residues. Conversely, CALB relies on an active-site-oriented approach with a weaker interfacial affinity. Additionally, the aqueous environment promotes lid closure in lipase PCL by stabilizing hydrogen bond networks and inducing conformational shifts in key flexible regions. This study elucidates polarity-driven interfacial activation mechanisms distinguishing lid-containing and lid-like lipases, offering atomistic insights for rational lipase engineering in nonaqueous environments.
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CHEMOSPHERE
·
2023
·
IF 8.8
Sini Lv,Fengzhen Zheng,Zeyu Wang,Luyao Dai,Huan Liu,Dzmitry Hrynshpan,Tatsiana Savitskaya,Jun Chen
The high hydrophobicity of n -hexane is the main reason why it is difficult to be removed biologically. In this study, the effects of bamboo-charcoal modified by bimetallic Fe/Pd (BBC) on n -hexane biodegradation by Pseudomonas mendocina NX-1 (PM) was investigated. The n- hexane removal efficiency was increased in the presence of BC. The highest n- hexane removal efficiency at 90.0% was achieved at 0.05 g L −1 BCE and 3 g L −1 NH 4 + under pH 7.7 and 35 °C. Additionally, protein content (45.9 μg mL −1 ) and negative cell surface zeta potential (−26.4 mV) were increased during biodegradation process, with PM-BBC being 43.1 μg mL −1 and 19.1 mV. Bacterial growth was improved and maximum cell surface hydrophobicity was obtained after 20 h, which was 59.4% higher than the control with PM-BBC (37.7%) or PM (16.1%), showing biodegradation products of 1-butanol and acetic acid. The results indicate that BBC improved n- hexane biodegradation efficiency by promoting bacterial growth, reducing cell zeta potential, exposing hydrophobic proteins, and increasing cell surface hydrophobicity of bacterial strain NX-1. This investigation suggests that BBC-enhanced biodegradation can be promising to treat n- hexane-containing gas.
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BIOCHEMICAL ENGINEERING JOURNAL
·
2023
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IF 3.9
Siyuan Chang,Bingfeng Li,Tianyi Chen,Leilei Zhang,Yaru Li,Xuejun He,Sen Zhang,Xin Pan
The catalytic transformation of biomass-derived 5-hydroxymethylfurfural (HMF) into value-added chemicals and biofuels has received considerable interest. Previously, we demonstrated that Pseudomonas aeruginosa PC-1 could be used for selective 900 mM HMF oxidation into 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) with over 90% yield. Here, we aimed to mine the potential aldehyde dehydrogenases (ALDHs) for HMF biocatalysis and improved the catalytic activity and tolerance through protein engineering. ALDHs were heterologously expressed in E. coli BL21 (DE3) and subsequently the most efficient HMF oxidation conditions of E. coli /pET -PaALDH70140 were identified. Based on the structural analysis of PaALDH70140 with the HMF and NAD + complexes, the engineering hotspots in the active site architecture were identified and subjected to saturation mutagenesis . The mutant L172R displayed 175% higher HMF catalytic efficiency than PaALDH70140, and the mutant also showed improved HMF-tolerance. Kinetic parameters suggested that L172R had higher HMF affinity and catalytic efficiency, indicating a higher HMF conversion efficiency than the wild-type. Molecular docking revealed that the mutation introduced new hydrogen bonds between the enzyme and HMF, which fixed the spatial position of HMF and shortened the reaction time of the catalysis, thus enhancing the catalytic efficiency of HMF. In the fed-batch process, E. coli /pET -PaALDH70140 - L172R exhibited a 166% increase in the yield of HMFCA within 22 h, proving its potential for HMF bioconversion applications.
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Journal of Environmental Sciences
·
2022
·
IF 6.796
Yunhao Zhang,Yi Qian,Ming Zhang,Weichuan Qiao
The wastewater discharge from the process of chrome plating, which contains 6:2 chlorinated polyfluorinated ether sulfonate (F-53B) and chromium (Cr), may be toxic to biofilm. In this study we found that the biofilm formed by Pseudomonas aeruginosa PAO1 was inhibited by exposure to a combination of F-53B and Cr(VI). The combined pollution damaged the cell membranes and the structure of the biofilm, and inhibited the production of the Pseudomonas quinolone-based signal, which affected biofilm formation. Moreover, the secretion of extracellular polymeric substances decreased as a result of this combined exposure. Exposure to F-53B and Cr(VI) individually or in combination could induce the excessive accumulation of intracellular reactive oxygen species (ROS), and the ROS positive rate of the bacteria increased under the treatment with 0.2 mmol/L of Cr(VI) and 250 nmol/L of F-53B, respectively. In addition, the activities of superoxide dismutase (SOD) and catalase (CAT) were enhanced for scavenging ROS in the bacteria that were exposed to Cr(VI) and F-53B. As an antioxidant, rutin was used to repair the toxicity of Cr(VI) and F-53B towards the biofilm formed by the bacteria. When rutin was added to the bacteria medium, with either Cr(VI) or F-53B as pollutant, or with the combined pollutants, the extracellular protein content of the bacteria recovered to 0.84, 0.94, and 0.85 times that of the control, respectively. Meanwhile, the accumulation of ROS and the activities of SOD and CAT decreased, which indicated that the addition of rutin can alleviate the oxidative stress and promote the antioxidant stress system.
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BIORESOURCE TECHNOLOGY
·
2022
·
IF 11.889
Kongyan Luo,Long Chen,Lei Du,Yuanyi Zhao,Qian Chen
Performance and molecular changes of an aerobic denitrifying phosphorus accumulating bacteria Pseudomonas psychrophila HA-2 have been investigated under different temperatures and ZnO nanoparticles (NPs) exposures. Strain HA-2 removed 95.7% of total nitrogen (TN) and 24.6% of phosphorus at 10 °C, which was attributed to the joint up-regulation of intracellular energy metabolism and ribosome. Moreover, with the increase of ZnO NPs from 0 to 100 mg/L, TN and phosphurs removal efficiencies decreased from 95.7% to 44.5% and 24.6% to 6.8% at 10 °C, respectively, whereas phosphorus removal rate increased from 10.5% to 24.5% at 20 °C. Further transcriptomics and proteomics revealed that significant down-regulation of purine and amino acid metabolisms was the main reason for the inhibitory effect at 10 °C, while the up-regulation of antioxidant pathways and functional genes expressions was responsible for the promoted phosphorus accumulation at 20 °C. This study provides a potential solution for improving biological nutrients removal processes in winter months.
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INTERNATIONAL JOURNAL OF PHARMACEUTICS
·
2022
·
IF 6.51
Yiqin Rao,Yingying Sun,Pengyu Li,Mao Xu,Xiaonan Chen,Yalong Wang,Yan Chen,Xin Deng,Shihui Yu,Haiyan Hu
Robust biofilms and the complex airway environment with thick sputum, local hypoxia and persistent inflammation induce the intractability of chronic pulmonary infections caused by Pseudomonas aeruginosa ( P. aeruginosa ). Herein, we proposed a type of antibiotic-adjuvant liposomes ( [email protected] ), co-incorporating azithromycin (AZI), adjuvant (2-nitroimidazole derivative, 6-NIH) and biofilm dispersant (nitric oxide donor, DETA NONOate). [email protected] possessing negatively-charged surface and good hydrophilicity could easily penetrate through the sputum layer, then disassembled triggered by overexpressed phospholipase A 2 (PLA 2 ) in the microenvironment around biofilms. Nitric oxide produced by DETA NONOate promoted P. aeruginosa biofilms dispersal. 6-NIH was reduced to 2-aminomidazole derivative (6-AIH) under a hypoxic condition, and hence acted as an AZI adjuvant to enhance the antibacterial activity of AZI. It was found that [email protected] could significantly eliminate mature P. aeruginosa biofilms, effectively kill dispersed bacteria, inhibit the metabolism of survivors and prevent P. aeruginosa adherence to airway epithelial cells, accordingly restrain recurrent infections. Additionally, [email protected] performed a remarkable advantage in killing AZI-resistant P. aeruginosa and removing their biofilms. In summary, [email protected] present a potential nano-strategy to treat stubborn pseudomonal pulmonary infections and overcome correlative drug resistance.
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