APPLIED AND ENVIRONMENTAL MICROBIOLOGY
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2024
·
IF 3.9
Chao-Fan Yin,Yong Nie,Tao Li,Ning-Yi Zhou
Many Acinetobacter species can grow on n-alkanes of varying lengths (≤C40). AlmA, a unique flavoprotein in these Acinetobacter strains, is the only enzyme proven to be required for the degradation of long-chain (LC) n-alkanes, including C32 and C36 alkanes. Although it is commonly presumed to be a terminal hydroxylase, its role in n-alkane degradation remains elusive. In this study, we conducted physiological, biochemical, and bioinformatics analyses of AlmA to determine its role in n-alkane degradation by Acinetobacter baylyi ADP1. Consistent with previous reports, gene deletion analysis showed that almA was vital for the degradation of LC n-alkanes (C26–C36). Additionally, enzymatic analysis revealed that AlmA catalyzed the conversion of aliphatic 2-ketones (C10–C16) to their corresponding esters, but it did not conduct n-alkane hydroxylation under the same conditions, thus suggesting that AlmA in strain ADP1 possesses Baeyer–Villiger monooxygenase (BVMO) activity. These results were further confirmed by bioinformatics analysis, which revealed that AlmA was closer to functionally identified BVMOs than to hydroxylases. Altogether, the results of our study suggest that LC n-alkane degradation by strain ADP1 possibly follows a novel subterminal oxidation pathway that is distinct from the terminal oxidation pathway followed for short-chain n-alkane degradation. Furthermore, our findings suggest that AlmA catalyzes the third reaction in the LC n-alkane degradation pathway.
研究领域:
微生物学
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酶学
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生物化学
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DOI
PubMed
高影响因子
ENZYME AND MICROBIAL TECHNOLOGY
·
2025
·
IF 3.7
Jing Wu,Zhenggang Han,Pengrong Li,Jing Li,Yuanyuan Chen,Shangbo Ning,Hong-jun Chao,Xue-wang Gao,Dazhong Yan
Cyclohexylamine oxidase is a member of amine oxidases that catalyzes the conversion of cyclohexylamine to cyclohexanone. In our previous work, the enzymatic activity assay of cyclohexylamine oxidase CHAO YT-02 indicated that its specific activity towards cyclohexylamine of CHAO YT-02 was ten times higher than that of its homolog CHAO IH-35A . In this study, the crystal structure of CHAO YT-02 was determined by the molecular replacement method at a resolution of 1.49 Å. The atomic structure revealed that the amino acid residues Leu302, Trp70, Phe197, Phe349, and Tyr440 constitute the active center pocket of the enzyme. Amino acid residues Ile180, Leu181, and Trp332 separate the active center pocket and an intermediate pocket. Moreover, a molecular dynamics (MD) simulation and the calculation of the binding free energy were performed to predict substrate entry and product release from cyclohexylamine oxidases. Single-amino acid substitution mutants (W70A, I180A, L181A, I208A, F197A, L302A, W332A, F349A, and Y440A) of CHAO YT-02 were constructed to investigate the role of these amino acid residues in enzymatic properties and substrate specificity. The results indicated that both the amino acid residues in the active center pocket and gating the two pockets affected the activity or substrate specificity of CHAO YT-02 . This study on the structure and catalytic mechanism of cyclohexylamine oxidase is beneficial to eliminating toxic amine compounds in the environment.
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DOI
PubMed
高影响因子
Frontiers in Microbiology
·
2025
·
IF 4.5
Yongtian Yuan,Liangliang Zhao,Zhuchun Bei,Baogang Wang,Dongna Zhang,Likun Xu,Jiahui Liu,Meng Lv,Qin Xu,Yabin Song
Introduction: Drug-resistant bacteria, particularly Acinetobacter baumannii, present a significant threat to global public health, highlighting the urgent need for novel antibacterial therapies. Drug repurposing has emerged as a promising strategy to accelerate therapeutic development by identifying new applications for existing pharmaceuticals. This study investigates the potential of naphthoquine phosphate (NQP), an antimalarial agent, as a broad-spectrum antibacterial candidate against the multidrug-resistant strain A. baumannii LAC-4.Methods: To evaluate the antibacterial activity of NQP, we determined the minimum inhibitory concentration (MIC) against Acinetobacter baumannii LAC-4. Inhibition kinetics were analyzed to assess concentration-dependent effects. Membrane permeability assays were performed to examine NQP-induced changes in cell membrane integrity. Oxidative damage tests were conducted to investigate impacts on bacterial metabolic processes. Morphological changes in A. baumannii LAC-4 treated with NQP of MIC were observed using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Additionally, transcriptome analysis was performed to identify disrupted physiological pathways associated with NQP exposure.Results and discussion: NQP exhibited broad-spectrum antibacterial activity, with a MIC of 62.5 μg/mL against Acinetobacter baumannii LAC-4. Its inhibition kinetics curve confirmed a concentration-dependent inhibitory effect. Membrane permeability tests revealed that NQP disrupts cell membrane integrity, enhancing permeability—consistent with TEM/SEM observations showing significant structural damage in NQP-treated A. baumannii, including membrane rupture, cellular deformation, and cytoplasmic disorganization. Oxidative damage tests indicated NQP impacts bacterial metabolism, and transcriptome analysis further demonstrated that NQP disrupts multiple physiological pathways, primarily through enhanced membrane permeability and induced oxidative stress. These findings support NQP as a promising molecular scaffold for developing novel therapies against Acinetobacter baumannii infections, highlighting its potential in drug repurposing strategies for combating drug resistance.
研究领域:
微生物学
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药理学
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抗菌素耐药性
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细胞生物学
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分子生物学
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药物再利用
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产品关联
DOI
PubMed
高影响因子
BIORESOURCE TECHNOLOGY
·
2020
·
IF 7.539
Zhe Dou,Guochao Xu,Ye Ni
A novel carboxylesterase Ac Est1 was identified from Acinetobacter sp. JNU9335 with high efficiency in the biosynthesis of chiral precursor of Edoxaban through kinetic resolution of methyl 3-cyclohexene-1-carboxylate (CHCM). Sequence analysis revealed Ac Est1 belongs to family IV of esterolytic enzymes and exhibits <40% identities with known carboxylesterases. The optimum pH and temperature of recombinant Ac Est1 are 8.0 and 40 °C. Substrate spectrum analysis indicated that Ac Est1 prefers substrates with short acyl and alcohol groups. Ac Est1 was highly active in the hydrolysis of CHCM with k cat of 1153 s −1 and displayed high substrate tolerance. As much as 2.0 M (280 g·L −1 ) CHCM could be enantioselectively hydrolyzed into ( S )-CHCM by merely 0.08 g·L −1 Ac Est1 with ee s of >99% ( S ) and substrate to catalyst ratio (S/C) of 3500 g·g −1 . These results indicate that the novel Ac Est1 is a promising biocatalyst in the synthesis of chiral carboxylic acids.
研究领域:
生物催化
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酶学
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药物化学
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DOI
PubMed
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2025
·
IF 19
Yun Li,Zhuorui Dong,Yingfei Ma,Jian Zhang,Yanan Wang,Dandan Cui,Kaifang Wang,Baojie Du,Runzhi Li,Zhifei Wang,Ruixue Wang,Bing Cao,Ruiping Zhang
Acinetobacter baumannii ( A. baumannii ) is a leading cause of pneumonia. Conventional antibiotics can increase the risk of drug resistance and non-specifically harm microflora, disrupting their balance. In addition to pathogenic bacteria, lung inflammation also damages tissue. This study develops an aptamer/polymer-functionalized mesoporous polydopamine/silver nanocomposite (Apt/ODEA-PDA/Ag-ICG) to specifically target A. baumannii and sequentially exhibit antibacterial/antioxidative properties for pneumonia treatment. After synthesizing the polyzwitterion (ODEA), the polymer/aptamer is conjugated with the PDA/Ag core, and ICG is further labeled to fabricate the nanocomposite. Upon intratracheal instillation, nanocomposites penetrate the mucus barrier with the help of polyzwitterions. The nanocomposite precisely targets A. baumannii through specific recognition by the aptamer, without affecting other microflora. Moreover, ICG is conjugated and distributed disorderedly within the polymer. ICG near the PDA/Ag core contributes to high NIR-I absorbance and good photothermal ability. ICG further from the PDA/Ag acts as a fluorescent molecule for specific A. baumannii imaging. Furthermore, PDA/Ag efficiently exhibits synergistic antibacterial activity owing to the acidic environment/heat-accelerated Ag + release and photothermal effect. Importantly, alongside Ag + release, the antioxidant ability of PDA scavenges reactive oxygen species and alleviates inflammation, thereby accelerating pneumonia treatment. In summary, nanocomposites provide an alternative approach for designing advanced antibacterial systems.
研究领域:
医学
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生物材料学
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纳米医学
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产品关联
DOI
高影响因子
EUROPEAN FOOD RESEARCH AND TECHNOLOGY
·
2019
·Vol. 245
·期 4
·825-835
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IF 2.056
Zhong Jian-Jun,Liao Ningbo,Li Charlie,Wang Wenjun,Wang Danli,Pu Yunfeng,Ye Xingqian,Liu Donghong
Urocanic acid, deaminated histidine and the first intermediate in the histidine utilization (Hut) pathway in bacteria, has recently been suggested to have adverse health effects by inducing scombrotoxicosis and immunosuppression after trans – cis isomerization. This work aimed to shed some light on the microbiology of its formation in scombroid fish, given that such information is very scarce. The isolation of urocanic acid producers from chub mackerel was basically based on enrichment of bacteria possessing the Hut pathway with histidine as the sole source of carbon, energy, and nitrogen. Morphological and molecular identification revealed that the isolates ( n = 12), taken from the skin, gills, and intestine, were comprised entirely of Acinetobacter from at least five species. This implies that the Hut pathway in the microbes can be particularly active and as such conferred a growth advantage. Dynamic monitoring of bacterial growth and urocanic acid production in fish juice broth indicated that urocanic acid is a primary metabolite and its production is a closely growth-associated process. This in turn implies that its production can be controlled directly by suppressing the bacterial growth. Several potential methods are proposed through a study of the growth characteristics and preservative susceptibility of representative isolates. In conclusion, this work suggests that Acinetobacter can constitute a potentially important group of urocanic acid producers in chub mackerel.
研究领域:
微生物学
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食品安全
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健康科学
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产品关联
DOI
高影响因子
BIORESOURCE TECHNOLOGY
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2022
·
IF 11.889
Siyue Han,Yue Tao,Yunhe Cui,Jiaming Xu,Hanxun Ju,Linlin Fan,Lin Zhang,Ying Zhang
A novel biobased composite was developed for the removal of phosphate (P) and atrazine from agricultural wastewater. A composite with strong P affinity and good biocompatibility, synthesized from La 3+ and polydopamine (PDA), was immobilized onto an atrazine-degrading bacterium Acinetobacter lwoffii DNS32 (La/PDA/DNS32). Following Box-Behnken design optimization, the maximum removal rate of P (500 mg L -1 ) and atrazine (100 mg L -1 ) by La/PDA/DNS32 reached 28 % and 100 %, respectively. Density functional theory calculations revealed that La/PDA had more negative adsorption energy (−5.90 eV) than PDA alone and exhibited prominent electrophilic sites. Additionally, La/PDA-induced sorption of atrazine improved transmembrane transport and enhanced expression of degradation-associated genes in strain DNS32. La/PDA nanoparticles surrounding strain DNS32 provided a shielding effect and exhibited desirable biostability, thermal stability, and acid-alkaline resistance under contamination stress. This study demonstrates the promising potential of La/PDA/DNS32 in reducing the P and atrazine pollution caused by agricultural production.
研究领域:
环境科学
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微生物学
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产品关联
DOI
PubMed
高影响因子
BIORESOURCE TECHNOLOGY
·
2023
·
IF 11.4
Yang Yang,Zhichao Kang,Jian Wang,Guanghui Xu,Yong Yu
Biochar-based bacteria are regarded as an efficient strategy for remediating organic pollutants in aquatic environments. Herein, a strain named Acinetobacter YH0317 that could degrade bensulfuron-methyl (BSM) at a lower temperature (15 °C) was isolated from a paddy rice field with long-term BSM application. Then Acinetobacter YH0317 was loaded on unmodified biochar (BC) and boron doping biochar (BBC). Results showed that BBC-based YH0317 significantly enhanced the removal efficiency of BSM (71.8–99.1%) compared with BC-based YH0317 (41.9–44.0%) and YH0317 alone (18.1–20.7%) in 24 h. BBC promoted the growth of YH0317 and secretion of extracellular secretions by providing a carrier and shelter for YH0317. The electrochemical analysis suggested BBC improved the electron transfer rate, which ultimately facilitated the removal of BSM. Hydroponic experiments indicated that BBC-based YH0317 effectively improved the growth of soybean. This work reports a novel BBC-based Acinetobacter YH0317 that could effectively remediate BSM contamination in the water environment.
研究领域:
环境科学
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微生物学
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生物修复
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农业科学
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DOI
PubMed
高影响因子
ENVIRONMENTAL POLLUTION
·
2023
·
IF 8.9
Edidiong Okokon Atakpa,Hanghai Zhou,Lijia Jiang,Dongdong Zhang,Yanhong Li,Wenjie Zhang,Chunfang Zhang
The widespread exploration and exploitation of crude oil has increased the prevalence of petroleum hydrocarbon pollution in the marine and coastal environment. Bioremediation of petroleum hydrocarbons using cell immobilization techniques is gaining increasing attention. In this study, the crude oil degradation performance of bacterial and fungal co-culture was optimized by entrapping both cells in sodium-alginate and polyvinyl alcohol composite beads. Results indicate that fungal cells remained active after entrapment and throughout the experiment, while bacterial cells were non-viable at the end of the experimental period in treatments with the bacterial-fungal ratio of 1:2. A remarkable decrease in surface tension from 72 mN/m to 36.51 mN/m was achieved in treatments with the bacterial-fungal ratio of 3:1. This resulted in a significant ( P < 0.05 ) total petroleum hydrocarbon (TPH) removal rate of 89.4%, and the highest degradation of n -alkanes fractions (from 2129.01 mg/L to 118.53 mg/L), compared to the other treatments. Whereas PAHs removal was highest in treatments with the most fungal abundance (from 980.96 μg/L to 177.3 μg/L). Furthermore, enzymes analysis test revealed that catalase had the most effect on microbial degradation of the target substrate, while protease had no significant impact on the degradation process. High expression of almA and PAH-RHDa genes was achieved in the co-culture treatments, which correlated significantly ( P < 0.05 ) with n -alkanes and PAHs removal, respectively. These results indicate that the application of immobilized bacterial and fungal cells in defined co-culture systems is an effective strategy for enhanced biodegradation of petroleum hydrocarbons in aqueous systems.
研究领域:
环境科学
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微生物学
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产品关联
DOI
PubMed
高影响因子
BIORESOURCE TECHNOLOGY
·
2015
·
IF 4.494
Ruijing Li,Xun-an Ning,Jian Sun,Yujie Wang,Jieying Liang,Meiqing Lin,Yaping Zhang
The strain Acinetobacter baumannii YNWH 226 was utilized to degrade Congo red (CR) under aerobic conditions. CR was employed as the sole carbon source to produce extracellular polymeric substances (EPS) used as potent bioflocculants in this strain. A total of 98.62% CR was removed during the 48-h decoloration experiments using CR (100 mg/L). A total of 83% bioadsorption and 65% biodegradation were responsible for the decoloration and degradation of CR through the strain. The bioflocculant showed high flocculation activity and dewaterability on textile dyeing sludge. A maximum flocculation of 78.62% with a minimum SBF of 3.07 × 10 9 s 2 /g and a CST of 58.4 s were achieved. We investigated the internal relationship between the decolorization efficiency of YNWH 226 and the flocculation activity and dewatering capacity of its EPS. The components and structure of the EPS highly influenced the decolorization efficiency of CR and the flocculation activity and dewatering capacity on sludge.
研究领域:
环境科学
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微生物学
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污水处理
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产品关联
DOI
PubMed
高影响因子
BMC MICROBIOLOGY
·
2022
·Vol. 22
·期 1
·1-13
·
IF 4.465
Guo Tingting,Sun Xiaoli,Yang Jie,Yang Liying,Li Mengying,Wang Yuhang,Jiao Hongmei,Li Guocai
Background Acinetobacter baumannii (A. baumannii) is an opportunistic pathogen and has emerged as one of the most troublesome pathogens. Drug resistance in A. baumannii has been reported on a global scale. Minocycline was found to be active against multi-drug resistant A. baumannii and was approved by the FDA for the infections caused by sensitive strains of A. baumannii. However, the emergence of minocycline resistance and its toxic effects still need to be addressed. Therefore, this study aimed to evaluate the synergistic effects of metformin combined with minocycline on minocycline-resistant A. baumannii . Results The effect of metformin on the antibacterial activity of minocycline was determined by checkerboard and time-killing assay. Further, it was observed by biofilm formation assay that metformin combination with minocycline can inhibit the formation of biofilm. Outer membrane integrity, membrane permeability, membrane potential and reactive oxygen species (ROS) were monitored to explore the underlying synergistic mechanisms of metformin on minocycline. And the results shown that metformin can destroy the outer membrane of A. baumannii , enhance its membrane potential, but does not affect the membrane permeability and ROS. Conclusion These findings suggested that the combination of metformin and minocycline has the potential for rejuvenating the activity of minocycline against minocycline-resistant A. baumannii .
研究领域:
微生物学
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药理学
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传染病学
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DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2024
·
IF 12.2
Yang Yang,Zhichao Kang,Guanghui Xu,Jian Wang,Yong Yu
Bensulfuron-methyl (BSM) is a typical broad-spectrum sulfonylurea herbicide and the runoff of BSM residues from agricultural regions poses a significant threat to the ecosystem. Here we develop a bacteria-material hybrid system constructed by Acinetobacter YH0317 and Mg(NO 3 ) 2 modified biochar (MBC) for efficiently degrading BSM under various conditions including pH and temperature. Results showed that BSM biodegradation efficiency by YH0317&MBC (96.7 %) was significantly higher than YH0317&BC (79.5 %) and YH0317 (43.9 %) at 15 °C after 7 d of incubation. The addition of MBC significantly increased the reactive oxygen species (ROS) level, which was significantly higher than group YH0317. Moreover, the bacterial viability, extracellular polymeric substances (EPS) production, and membrane permeability of YH0317 were also enhanced with the addition of MBC. The electron paramagnetic resonance (EPR) and quenching experiments revealed that singlet oxygen ( 1 O 2 ) was the dominant active substance produced by MBC. The YH0317&MBC could effectively remove the BSM, and reduce the oxidative stress to soybean, which was beneficial to the growth of soybean through hydroponic experiment. This study establishes a microorganism-material system that efficiently removes BSM in aquatic environments and emphasizes the importance of ROS in pollution removal by the hybrid system.
研究领域:
环境科学
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微生物学
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生物技术
·
农业化学
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产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）