JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE
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2019
·Vol. 99
·期 8
·4123-4128
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IF 2.422
Fengchuan Yu,Yajun Bai,Tai-ping Fan,Xiaohui Zheng,Yujie Cai
BACKGROUND Cheese ripening involves a complex series of metabolic reactions and numerous concomitant secondary transformations. Alcohol dehydrogenase (ADH) converts aldehydes into their corresponding alcohols, which enrich cheese aroma. RESULTS In this study, we identified five ADH genes in Proteus mirabilis JN458, and these genes were overexpressed and characterized in Escherichia coli BL21 (DE3). The optimum pH was 7.0 for the purified recombinant ADH-1, ADH-2, and ADH-3 and 8.0 for ADH-4 and ADH-5. The optimum temperature was 40 °C for ADH-1, ADH-3, and ADH-5 and 45 °C for ADH-2 and ADH-4. The K m value of ADH-1, ADH-2, and ADH-3 was 34.45, 16.90, and 10.01 µmol L −1 for phenylacetaldehyde, respectively. The K m value of ADH-4 and ADH-5 was 14.81 and 24.62 µmol L −1 for 2-methylbutanal, respectively. CONCLUSION Proteus species play important roles during cheese ripening. The results of our study are important for further research on cheese flavor and for quality control during cheese production. © 2019 Society of Chemical Industry
研究领域:
食品科学
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微生物学
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生物化学
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MICROCHIMICA ACTA
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2020
·Vol. 187
·期 7
·1-8
·
IF 6.232
Yao Wenyan,Shi Jian,Ling Jiang,Guo Yadong,Ding Chensen,Ding Yanjun
Aptamer-modified SiC quantum dots (DNA-SiC QDs) as fluorescent aptasensor are described for the determination of Proteus mirabilis . The SiC QDs were synthesized through one-pot hydrothermal method with particle sizes of about 14 nm. The amino-modified aptamers against P. mirabilis were conjugated to the surfaces of SiC QDs for bacteria recognition . The aptamer with an affinity for target protein can bound to P. mirabilis and this causes a decrease in the fluorescence intensity of DNA-SiC QDs. P. mirabilis levels were tested by the aptasensor within 35 min with fluorescence excitation/emission maxima at 320/420 nm. The linear range is from 10 3 to 10 8 CFU mL −1 and the limit of detection is 526 CFU mL −1 ( S / N = 3). The aptasensor was used for determination of P. mirabilis in pure milk samples and obtained good accuracy (87.6–104.5%) and recovery rates (85–110.2%) were obtained. The detection in simulated forensic identification samples (pure milk, milk powder, blood, and urine) obtained gave satisfactory coincidence rates with the method of bacterial isolation and identification as standard. These results demonstrate that the fluorescent aptasensor is a potential tool for identification of P. mirabilis in forensic food poisoning cases.
Determination of P. mirabilis is based on SiC QDs fluorescence aptasensor. The SiC QDs with plentiful carboxyl groups on the surface can be synthesized via one-pot hydrothermal route. After activated by EDC/NHS, the SiC QDs can bind to aptamer to form fluorescence aptasensors. When the target P. mirabilis exists, the fluorescence of aptasensor will be quenched and the determination of the P. mirabilis based on the fluorescence change can be analyzed.
研究领域:
生物传感技术
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微生物学
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食品安全检测
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高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2020
·
IF 4.192
Jinbin Liu,Yajun Bai,Tai-ping Fan,Xiaohui Zheng,Yujie Cai
Proteus mirabilis could convert l-phenylalanine into 2-phenylethanol (2-PE) via the Ehrlich pathway, the amino acid deaminase pathway, and the aromatic amino acid decarboxylase pathway. The aromatic amino acid decarboxylase pathway was proved for the first time in P. mirabilis. In this pathway, l-aromatic amino acid transferase demonstrated a unique catalytic property, transforming 2-penylethylamine into phenylacetaldehyde. Eleven enzymes were supposed to involve in 2-phenylethanol synthesis. The mRNA expression levels of 11 genes were assessed over time by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) in vivo. As a result, the expression of 11 genes was significantly increased, suggesting that P. mirabilis could transform l-phenylalanine into 2-phenylethanol via three pathways under aerobic conditions; nine genes were significantly overexpressed, suggesting that P. mirabilis could synthesize 2-phenylethanol via the Ehrlich pathway under anaerobic conditions. This study reveals the multipath synthetic metabolism for 2-phenylethanol in P. mirabilis and will enrich the new ideas for natural (2-PE) synthesis.
研究领域:
微生物学
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生物化学
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代谢工程
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高影响因子
BIOTECHNOLOGY LETTERS
·
2022
·Vol. 44
·期 5
·635-642
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IF 2.716
Liu Jia,Liu Jianmin,Yang Bin,Gao Cong,Song Wei,Hu Guipeng,Liu Liming,Wu Jing
Objectives This study aimed to develop an efficient enzymatic strategy for the industrial production of phenylpyruvate (PPA) from l -phenylpyruvic acid ( l -Phe). Results l -amino acid deaminase from Proteus mirabilis was expressed in Escherichia coli BL21 (DE3) and modified to release product inhibition by employing conformational dynamics engineering. Based on structural analysis, two residues (E145/L341) were identified for reducing interactions between the product and enzyme and increasing flexibility of the protein, thereby facilitating the product release. The mutant M2 E145A/E341A exhibited a 3.84-fold reduction in product inhibition and a 1.35-fold increase in catalytic efficiency in comparison to the wild type. Finally, 81.2 g/L PPA production with a conversion of 99.6% was obtained in a 5-L bioreactor. Conclusions The engineered catalyst can significantly reduce product inhibition and facilitate the effective industrial synthesis of PPA.
研究领域:
生物化学
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工业微生物学
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高影响因子
INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY
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2025
·
IF 5.2
Xiao-li Liu,Si-yi Wu,Zhan-peng Zou,Xiting Xian,Jingyuan Wang,Li Min,Yuanyuan Zhou,Kurt Houf,Zhongjia Yu
Proteus mirabilis , a well-known urinary tract pathogen, is increasingly recognized as a food safety concern due to its frequent detection in meat products, particularly poultry. Sporadic reports indicate gastrointestinal symptoms linked to P. mirabilis , but the relationship between its genome, antibiotic resistance, and variable pathogenicity remains unclear. In this study, 142 P. mirabilis isolates were collected from broiler carcasses and processing environments in wet markets and industrial facilities to assess contamination levels. Thirty-six representative isolates were characterized for genomic heterogeneity, antibiotic resistance, and virulence gene profiles using whole-genome sequencing and phenotypic susceptibility testing. Selected strains were further assessed for intestinal pathogenicity in a murine model. Broiler carcasses from wet markets had significantly higher contamination rates (80.77 %, 21/26) than industrial sources (41.67 %, 5/12), with all wet market samples (13/13) testing positive. Overall, 94.4 % of isolates were multidrug-resistant, with carcass isolates showing higher resistance than environmental isolates. Animal experiments demonstrated variable pathogenicity, including intestinal injury, villus disruption, epithelial shedding, goblet cell loss, inflammatory cytokine elevation, and gut dysbiosis. Dysbiosis induced by certain strains (e.g., R638) was linked to intestinal injury, as confirmed by fecal microbiota transplantation. These findings highlight P. mirabilis as a highly heterogeneous foodborne pathogen, emphasizing the need for targeted hygiene practices, particularly in wet market processing environments.
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FOOD CHEMISTRY
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2017
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IF 4.529
Biying Wang,Yajun Bai,Taiping Fan,Xiaohui Zheng,Yujie Cai
Alpha-keto acid decarboxylases can convert keto acids to their corresponding aldehydes, which are often volatile aroma compounds. The gene encoding α-keto acid decarboxylase in Proteus mirabilis JN458 was cloned, and the enzyme overexpressed in Escherichia coli BL21 (DE3), purified in high yield, and characterised. The molecular weight is 62.291 kDa by MALDI-TOF MS, and optimum activity at pH 6.0 and 40–50 °C. The enzyme is a typical decarboxylase, dependent on thiamine diphosphate and Mg 2+ as cofactors. For the decarboxylation reaction, the enzyme displayed a broad substrate range. Kinetic parameters were determined using 4-methyl-2-oxopentanoic acid, phenyl pyruvate and 3-methyl-2-oxopentanoic acid as substrates. K m and k cat values for phenyl pyruvate were 0.62 mM and 77.38 s −1 , respectively, and the k cat / K m value was 124.81 mM −1 s −1 . The enzyme properties suggest it may act effectively under cheese ripening conditions.
研究领域:
生物化学
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食品科学
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微生物学
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2018
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IF 3.412
Jinbin Liu,Jing Jiang,Yajun Bai,Tai-ping Fan,Ye Zhao,Xiaohui Zheng,Yujie Cai
Bacteria rarely produce natural 2-phenylethanol. We verified a new pathway from Proteus mirabilis JN458 to produce 2-phenylethanol using Escherichia coli to coexpress l-amino acid deaminase, α-keto acid decarboxylase, and alcohol dehydrogenase from P. mirabilis. Based on this pathway, a glucose dehydrogenase coenzyme regeneration system was constructed. The optimal conditions of biotransformation by the recombinant strain E-pAEAKaG were at 40 °C and pH 7.0. Finally, the recombinant strain E-pAEAKaG produced 3.21 ± 0.10 g/L 2-phenylethanol in M9 medium containing 10 g/L l-phenylalanine after a 16 h transformation. Furthermore, when the concentration of l-phenylalanine was 4 g/L (24 mM), the production of 2-phenylethanol reached 2.88 ± 0.18 g/L and displayed a higher conversion rate of 97.38 mol %.
研究领域:
微生物学
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生物化学
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代谢工程
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高影响因子
Frontiers in Microbiology
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2017
·
IF 4.076
Jiang Xiaobing,Yu Tao,Liu Lei,Li Yi,Zhang Kun,Wang Hailei,Shi Lei
The aim of this study was to examine the presence of genes responsible for resistance to quaternary ammonium compounds (QACs) and the association of qac genes with class 1 integrons in Proteus mirabilis isolated from cooked meat products. A total of 52 P. mirabilis isolates (29.2%) were detected from 178 samples, and their minimum inhibitory concentrations (MICs) of benzalkonium chloride (BC) ranged from 4 to >32 μg/mL. The isolates with BC MICs of 24 μg/mL were observed most frequently. PCR assays indicated that mdfA, ydgE/ydgF, qacE, qacEΔ1, emrE, sugE(c), and sugE(p) were commonly present (32.7%–100%) in these isolates, but qacH was less prevalent (3.8%). Five groups of resistance gene cassettes were identified in 10 intI1-positive isolates. An unusual gene cassette array dfrA32-ereA-aadA2 was found in one foodborne isolate of P. mirabilis. Two isolates harbored qacH- and sul3- associated non-classic integrons: aadA2-cmlA1-aadA1-qacH-IS440-sul3 and a new arrangement dfrA32-ereA1-aadA2-cmlA1-aadA1-qacH-IS440-sul3, which is first reported in P. mirabilis. Non-classic class 1 integrons were located on conjugative plasmids of 100 kb in two tested isolates. Our data showed that the QAC resistance genes were commonly present among P. mirabilis isolates from cooked meats and qacH was associated with non-classic class 1 integrons. The creation of transconjugants demonstrated that qacH-associated non-classic class 1 integrons were located on conjugative plasmids and therefore could facilitate the co-dissemination of disinfectant and antimicrobial resistance genes among bacteria, an increasing area of concern.
研究领域:
微生物学
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食品安全
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分子生物学
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高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2020
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IF 2.627
Shanshan Pei,Xiaobo Ruan,Jia Liu,Wei Song,Xiulai Chen,Qiuling Luo,Liming Liu,Jing Wu
l -Amino acid deaminase (LAAD) is a key enzyme in the deamination of l -valine ( l -val) to produce α-ketoisovalerate (KIV). However, the product inhibition of LAAD is a major hindrance to industrial KIV production. In the present study, a combination strategy of modification of flexible loop regions around the product binding site and the avoidance of dramatic change of main-chain dynamics was reported to reduce the product inhibition. The four mutant PM-LAAD M4 (PM-LAAD S98A/T105A/S106A/L341A ) achieved a 6.2-fold higher catalytic efficiency and an almost 6.7-fold reduction in product inhibition than the wild-type enzyme. Docking experiments suggested that weakened interactions between the product and enzyme, and the flexibility of the “lid” structure relieved LAAD product inhibition. Finally, the whole-cell biocatalyst PM-LAAD M4 has been applied to KIV production, the titer and conversion rate of KIV from l -val were 98.5 g·L −1 and 99.2% at a 3-L scale, respectively. These results demonstrate that the newly engineered catalyst can significantly reduce the product inhibition, that making KIV a prospective product by bioconversion method, and also provide the understanding of the mechanism of the relieved product inhibition of PM-LAAD.
研究领域:
生物技术
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酶学
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生物化工
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高影响因子
FOOD RESEARCH INTERNATIONAL
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2026
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IF 8.8
Chuying Wang,Yujie Niu,Xiaowu Yu,Peng Zhang,Qicheng Lu,Yanfang Li,Yan Liang,Yonggang Qu,Wenju Zhang
Proteus mirabilis harbors multiple antibiotic resistance and virulence genes. • vB_PMG_YP1 is a safe phage and remains stable under a range of conditions. • The phage reduces Proteus mirabilis on food matrices at 4 °C and 25 °C. • The phage vB_PMG_YP1 application preserves food sensory qualities. Proteus mirabilis ( P. mirabilis ) is frequently detected in the food supply chain, particularly in meat and fresh produce. It carries antibiotic resistance genes (ARGs) and virulence factors, which pose significant risks to food safety and public health. Phages are considered a promising natural antimicrobial agent capable of effectively eliminating multidrug-resistant (MDR) pathogens. However, the application of phages to control MDR P. mirabilis in the food supply chain remains relatively limited. In this study, the P. mirabilis isolate carried seven virulence factors, one class 1 integron, and four ARGs, showing resistance to 94.74% (18/19) of the tested antibiotics. We isolated and characterized a lytic P. mirabilis phage, vB_PMG_YP1. Genomic analyses revealed that vB_PMG_YP1 belongs to the genus Privateervirus . vB_PMG_YP1 encodes tRNA genes and lacks genes associated with antibiotic resistance, virulence, or lysogeny. vB_PMG_YP1 maintained activity from 4 to 60 °C and across pH 3–11. The optimal multiplicity of infection (MOI) was 0.1, with a burst size of 240 phages per cell. The spot assay (60.87%, 14/23) and EOP test showed that vB_PMG_YP1 possesses a moderate lytic spectrum against P. mirabilis. vB_PMG_YP1 provided sustained suppression of P . mirabilis on chicken breast, pork tenderloin, and lettuce at 4 °C, whereas at 25 °C it achieved more rapid and robust inhibition. Under both 4 °C and 25 °C conditions, phage treatment did not significantly affect the color, texture, odor, or overall acceptability of any food matrix. These findings suggest vB_PMG_YP1 as a potential biocontrol candidate for reducing MDR P. mirabilis on food matrices. Download: Download high-res image (57KB) Download: Download full-size image
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PROTEIN EXPRESSION AND PURIFICATION
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2024
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IF 1.4
Junzhang Chang,Yuxin Zhang,Zhiwei Li,Yunfeng Ma,Xueqin Hu,Jingwen Yang,Hongbin Zhang
Chiral amino acids and their deamination products, α-keto acids, have important applications in food, medicine, and fine chemicals. In this study, two l -amino acid deaminase genes from Proteus mirabilis , PM473 of type Ⅰ and PM471 of type Ⅱ were cloned and expressed in Escherichia coli respectively, expected to achieve the chiral separation of amino acids . Extensive substrate preference testing showed that both deaminases had catalytic effects on the d -amino acid component of the D, l -amino acids, and PM473 has a wider catalytic range for amino acids. When D, L-Cys was used as the substrate, all L-Cys components and 75.1 % of D-Cys were converted to mercapto pyruvate , and the remaining D-Cys was a single chiral enantiomer . Molecular docking analysis showed that the interaction between the substrate and the key residues affected the stereoselectivity of enzymes . The compatibility of hydrophobicity between the binding pocket and substrate may be the basic factor that affects the substrate selectivity. This work provides an alternative method for the production of α-keto acids and the resolution of chiral amino acids.
研究领域:
生物化学
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生物催化
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酶学
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药物化学
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高影响因子
Journal of Materials Chemistry B
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2024
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IF 6.1
Jiru Miao,Haiyang Chai,Longxing Niu,Mi Ouyang,Rong Wang
Catheter-associated urinary tract infection is one of the most common hospital-acquired infections. Proteus mirabilis, a common pathogen associated with urinary tract infections, has swarming motility and has pili on its surface for adhesion and flagella for upward movement. Migration of P. mirabilis along the catheter surface can lead to ascending urinary tract infection. However, there is currently a lack of effective strategies to inhibit or delay the colonization, migration, and encrustation formation of P. mirabilis in urinary catheters. This study developed a method for constructing a stable superhydrophobic coating on the surface of urinary catheters using a layer-by-layer approach. The adhesion and deposition of polydopamine were enhanced by pre-coating a liquid bandage film on the polydimethylsiloxane surface, resulting in a multilayer micro-nano composite structure on the catheter surface. This structure was combined with copper ions and superhydrophobic modifiers, ultimately achieving a highly stable superhydrophobic coating. The coating retains its superhydrophobic properties after prolonged incubation, friction tests, and tape peeling tests. Importantly, the coating demonstrates excellent efficacy in inhibiting P. mirabilis colonization, migration, and encrustation formation. This study offers novel insights into developing biomedical superhydrophobic coatings with enhanced stability and efficacy in inhibiting urinary tract bacterial infections.
研究领域:
生物医学工程
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材料科学
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微生物学
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传染病学
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高影响因子
危险品化学品经营许可证（带存储）