JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2023
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IF 6.1
Lian Wang,Huijing Wang,Jianbin Chen,Minglong Hu,Xiaoyu Shan,Jingwen Zhou
Chlorogenic acid is a natural phenolic compound widely used in the food and daily chemical industries. Compared to plant extraction, microbial cell factories provide a green and sustainable production method for the production of chlorogenic acid. However, complex metabolic flux distribution and potential byproducts limited the biosynthesis of chlorogenic acid in microorganisms. A de novo biosynthesis pathway for chlorogenic acid was constructed in Escherichia coli via modular engineering. Increasing the shikimate pathway flux greatly promoted chlorogenic acid production, and the influence of pyruvate metabolism on chlorogenic acid synthesis was also explored. The supply of cofactors for the key enzymes quinate/shikimate 5-dehydrogenase (YdiB) and 4-hydroxyphenylacetate 3-monooxygenase (HpaBC) was enhanced by a cofactor regeneration system. Furthermore, mutants of YdiB were verified for chlorogenic acid production in vivo. Chlorogenic acid browning occurred when the buffer pH of the buffer exceeded 6.0, but two-stage pH control achieved a chlorogenic acid titer of 2789.2 mg/L in a 5 L fermenter, the highest reported to date. This study provided a strategy for the efficient production of chlorogenic acid from simple carbon sources.
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BIORESOURCE TECHNOLOGY
·
2023
·
IF 11.4
Yufei Zhang,Junhua Yun,Guoyan Zhang,Amreesh Parvez,Lei Zhou,Hossain M. Zabed,Jia Li,Xianghui Qi
3-Hydroxypropionic acid (3-HP) is a top value-added chemical with multifaceted application in chemical, material, and food field. However, limited availability of robust strains and elevated fermentation costs currently impose constraints on sustainable biosynthesis of 3-HP. Herein, transporter engineering, metabolic dynamic modulation, and enzyme engineering were combined to address above limitations. First, a glucose-utilizing 3-HP biosynthetic pathway was constructed in Escherichia coli , followed by recruiting alternative glucose transport system to overcome center metabolism overflow. Next, the Cra (a transcription factor)-dependent switch was applied to autonomously fine-tune carbon flux, which alleviated growth retardation and improved the 3-HP production. Subsequently, inactivation of glycerol facilitator (GlpF) increased intracellular glycerol levels and boosted 3-HP biosynthesis, but caused toxic intermediate 3-hydroxypropionaldehyde (3-HPA) accumulation. Furthermore, semi-rational design of aldehyde dehydrogenase (YdcW) increased its activity and eliminated 3-HPA accumulation. Finally, fed-batch fermentation of the final strain resulted in 52.73 g/L 3-HP, with a yield of 0.59 mol/mol glucose.
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LANGMUIR
·
2023
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IF 3.9
Lingling Zhao,Yue Ma,Zhaomeng Sun,Xiaoqing Zhang,Mei Liu
Bacterial infections and antibiotic abuse are a global threat to human health. In recent years, there has been a boom in research on antimicrobial agents with low toxicity and efficient nanomaterials. Boric acid-functionalized carbon dots (B-CDs) with negative surface charge were synthesized by the hydrothermal method. Covalent bonds were formed between the boric acid groups and the cis-diol groups of the polysaccharide in the bacterial cell wall, and numerous B-CDs were trapped on the bacterial surface. In the experiments of antibacterial activity, B-CDs presented strong bactericidal activity against Escherichia coli (E. coli) with a minimum bactericidal concentration of 12.5 μg/mL. The antibacterial mechanism suggested that B-CDs entered the cell interior by diffusion and posed significant damage to the double helix structure of E. coli DNA. Furthermore, B-CDs exhibited low toxicity. The results demonstrated that the novel antimicrobial B-CDs not only fought against E. coli infection and antibiotic misuse but also provided new ideas for safe and effective antimicrobial agents of carbon nanomaterials.
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JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2023
·Vol. 98
·期 10
·2597-2609
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IF 3.4
Jun Chen,Xiaohong Yang,Shangqing Xia,Xue Li,Yutong Wang,Zongsheng Zhan,Mingxia Du,Dongliang Shao
BACKGROUND Persulfate (PS) has the capability to yield free radicals via activators, thereby shaping an advanced oxidation process that can significantly contribute to effective sterilization. Central to this technology is the pursuit of appropriate activators. RESULTS In our research, we successfully synthesized an economical and efficient PS activator, namely a pyrrhotite-loaded sludge carbon (Pyr-SC) composite. This was achieved via a straightforward procedure utilizing two environmentally friendly and cost-efficient raw materials: pyrite and sludge. Pyr-SC exhibited a specific surface area of 60.4 m 2 g −1 and rich functional groups such as carbon–sulfur and sulfur–oxygen. The magnetic and graphitic carbon structures were formed at high temperatures during the preparation process, and the sludge carbon (SC) exhibited porous defects, which allowed the effective insertion of iron/sulfur into SC to form the stable Pyr-SC structure. Pyr-SC activated PS, which further sterilized Escherichia coli in the wastewater at a sterilization rate of 7.00 lg E. coli at 10 7 cfu mL −1 in 80 min. The sterilization rate was less affected by temperature and pH. We verified sulfate, hydroxyl and oxygen free radicals produced by the Pyr-SC-activated PS. The Pyr-SC composite, thanks to its expedited electron transfer, could activate PS to engender free radicals. Furthermore, the oscillatory transformation of iron ions caused by the monosulfide ion on the Pyr-SC surface augmented the production of free radicals. An assessment of Pyr-SC's stability was conducted, adhering to the principles of magnetic separation. After five cycles in the Pyr-SC/PS reaction system, the sterilization rate reached 3.29 lg, whereas the leaching rate of iron in Pyr-SC decreased. The Pyr-SC/PS reaction system also had a broad spectrum of wastewater. CONCLUSION The economically prepared Pyr-SC composite provided an effective technology for activating PS and sterilizing microorganisms in wastewater. © 2023 Society of Chemical Industry.
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VETERINARY RESEARCH
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2023
·Vol. 54
·期 1
·1-12
·
IF 4.4
Fu Shaodong,Wang Zhenglei,Han Xiangan,Xu Yuanyuan,Miao Jinfeng
Macrophages play a pivotal role in the inflammatory response to the zoonotic pathogen E. coli, responsible for causing enteric infections. While considerable research has been conducted to comprehend the pathogenesis of this disease, scant attention devoted to host-derived H2S. Herein, we reported that E. coli infection enhanced the expression of CSE in macrophages, accompanied by a significantly increased inflammatory response. This process may be mediated by the involvement of excessive autophagy. Inhibition of AMPK or autophagy with pharmacological inhibitors could alleviate the inflammation. Additionally, cell model showed that the mRNA expression of classic inflammatory factors (Il-1β, Il-6), macrophage polarization markers (iNOS, Arg1) and ROS production was significantly down-regulated after employing CSE specific inhibitor PAG. And PAG is capable of inhibiting excessive autophagy through the LKB1-AMPK-ULK1 axis. Interestingly, exogenous H2S could suppress inflammation response. Our study emphasizes the importance of CSE in regulating the macrophage-mediated response to E. coli. Increased CSE in macrophages leads to excessive inflammation, which should be considered a new target for drug development to treat intestinal infection.
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BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
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2023
·
IF 3.1
Liangwan Wei,Zhe Wang,Yindi Chu,Kun Cai,Wei Li,Piying Huang,Youcai Qin,Dailin Liu,Xiaocui Zhuang,Mingquan Guo,Xinbo Song,Enguo Fan
Antimicrobial resistance (AMR) crisis urges the development of new antibiotics. In the present work, we for the first time used bio-affinity ultrafiltration combined with HPLC-MS (UF-HPLC-MS) to examine the interaction between the outer membrane β-barrel proteins and natural products. Our results showed that natural product licochalcone A from licorice interacts with BamA and BamD with the enrichment factor of 6.38 ± 1.46 and 4.80 ± 1.23, respectively. The interaction was further confirmed by use of biacore analysis, which demonstrated that the Kd value between BamA/D and licochalcone was 6.63/28.27 μM, suggesting a good affinity. To examine the effect of licochalcone A on BamA/D function, the developed versatile in vitro reconstitution assay was used and the results showed that 128 μg/mL licochalcone A could reduce the outer membrane protein A integration efficiency to 20%. Although licochalcone A alone can not inhibit the growth of E. coli , but it can affect the membrane permeability , suggesting that licochalcone A holds the potential to be used as a sensitizer to combat AMR.
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JOURNAL OF BASIC MICROBIOLOGY
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2023
·
IF 3.1
Panmei Jiang,Yingxiang Ye,Jian Liu,Fangbin Wang
The antiglycemic drug metformin, which is widely prescribed as a first-line drug for the treatment of type 2 diabetes, has become a concern for emerging pollutants in natural ecosystems. However, its effects on bacterial swimming motility remain unclear. In this study, we showed that metformin promotes bacterial surface aggregation by tracking swimming and by measuring the density distribution of Escherichia coli cultured with metformin near a surface in a homogeneous environment. Flagella are essential for the promotion of bacterial surface aggregation by metformin. Swimming motility, which is mediated by flagella, determines bacterial surface aggregation. The promotion of bacterial surface aggregation by metformin is caused by a reduction in swimming motility, which is governed by a decrease in the proton motive force. Our results reveal that metformin has a pronounced effect on flagellated bacterial motility associated with surface sensing and aggregation.
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METABOLIC ENGINEERING
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2023
·
IF 8.4
Peichao Zhang,Jing Gao,Haiyang Zhang,Yongzhen Wang,Zhen Liu,Sang Yup Lee,Xiangzhao Mao
Zosteric acid (ZA) is a Zostera species-derived, sulfated phenolic acid compound with antifouling activity and has gained much attention due to its nontoxic and biodegradable characteristics. However, the yield of Zostera species available for ZA extraction is limited by natural factors, such as season, latitude, light, and temperature. Here we report the development of metabolically engineered Escherichia coli strains capable of producing ZA from glucose and glycerol. First, intracellular availability of the sulfur donor 3′-phosphoadenosine-5′-phosphosulfate (PAPS) was enhanced by knocking out the cysH gene responsible for PAPS consumption and overexpressing the genes required for PAPS biosynthesis . Co-overexpression of the genes encoding tyrosine ammonia-lyase, sulfotransferase 1A1, ATP sulfurylase, and adenosine 5′-phosphosulfate kinase constructed ZA producing strain with enhanced PAPS supply. Second, the feedback-resistant forms of aroG and tyrA genes (encoding 3-deoxy- d -arabinoheptulosonate 7-phosphate synthase and chorismate mutase , respectively) were overexpressed to relieve the feedback regulation of L- tyrosine biosynthesis. Third, the pykA gene involved in phosphoenolpyruvate-consuming reaction, the regulator gene tyrR , the competing pathway gene pheA , and the ptsHIcrr genes essential for the PEP:carbohydrate phosphotransferase system were deleted. Moreover, all genes involved in the shikimate pathway and the talA , tktA , and tktB genes in the pentose phosphate pathway were examined for ZA production. The PTS-independent glucose uptake system, the expression vector system, and the carbon source were also optimized. As a result, the best-performing strain successfully produced 1.52 g L −1 ZA and 1.30 g L −1 p -hydroxycinnamic acid from glucose and glycerol in a 700 mL fed-batch bioreactor .
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JOURNAL OF FOOD PROTECTION
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2018
·
IF 1.51
Jianyu Wang,Maomao Ma,Jun Yang,Long Chen,Ping Yu,Jun Wang,Deming Gong,Shuguang Deng,Xuefang Wen,Zheling Zeng
ABSTRACT In the present study, the antibacterial activity of monocaprylin in comparison with sodium benzoate and potassium sorbate against Staphylococcus aureus and Escherichia coli was assessed by measuring MIC, MBC, effect of pH on MIC, and incubation temperature on bactericidal efficacy. Results showed that monocaprylin exhibited an excellent antibacterial activity against both strains, with the lowest MIC and MBC of 1.28 mg/mL. A MIC of monocaprylin remained unchanged despite the pH values of culture medium, ranging from 5 to 9, unlike that of potassium sorbate or sodium benzoate. Furthermore, monocaprylin at MBC effectively reduced the population of E. coli and S. aureus by >5.5 log CFU/mL at 25°C within 6 h and decreased E. coli by approximately 5.0 log CFU/mL and S. aureus by 2.9 log CFU/mL at 12 h. The underlying mechanism of monocaprylin was then investigated by measuring β-galactosidase activity, membrane potential, release of cellular contents, scanning electron microscopy, and transmission electron microscopy observations. Results indicated that monocaprylin killed E. coli by the rapid change in permeability and integrity of cell membrane, leading to decline of membrane potential, leakage of nucleic acids and proteins, and ultimately cell membrane disintegration and lysis. On the other hand, monocaprylin might exert its antibacterial activity against S. aureus mainly by diffusing across the cell wall, collapsing the cell membrane, and disturbing the order of intracellular contents. These findings indicated that monocaprylin had better antibacterial ability compared with traditional synthetic preservatives and might be a potential antibacterial additive independent of pH.
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JOURNAL OF HAZARDOUS MATERIALS
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2018
·
IF 6.434
Minrui Liu,Xia Lu,Aman Khan,Zhenmin Ling,Peng Wang,Yu Tang,Pu Liu,Xiangkai Li
Seafood consumption is widely considered as the primary route for human exposure to the neurotoxin methylmercury (MeHg) that is produced by certain anaerobic microorganisms and can bioaccumulate to high concentration levels in natural aquatic food webs. In this study, a novel methylmercury-binding peptide with seven amino acids was displayed on the cell surfaces of Escherichia coli strain W-1, which was isolated from fish feces and fused with ice nucleation protein. These cells exhibited high affinity and selectivity toward methylmercury. They efficiently removed more than 96% of 12 μM methylmercury, and accumulation of methylmercury in the engineered strain was four times higher than that in the wild type. Transmission electron microscopy confirmed methylmercury accumulation on cell membranes. Carassius auratus was fed by engineered bacteria, which showed a decrease in methylmercury concentration in muscles of about 36.3 ± 0.7%; whereas an increase in methylmercury concentration was observed in the feces (36.7 ± 0.8%) in comparison to the control group. The engineered strain in the gut captured methylmercury and prevented it’s absorption by muscles, while some bacteria with methylmercury were excreted in the feces. The surface-engineered E. coli effectively protected fish from methylmercury contamination.
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FOOD CONTROL
·
2019
·
IF 4.248
Qisen Xiang,Wenjie Wang,Dianbo Zhao,Liyuan Niu,Ke Li,Yanhong Bai
This study was designed to evaluate the synergistic antimicrobial effect of plasma-activated water (PAW) combined with mild heat (40, 50, and 60 °C) against Escherichia coli O157:H7. Populations of E. coli O157:H7 were reduced from about 8.28 log CFU/mL to undetectable levels following exposure to the combined treatment of PAW and mild heat (60 °C, 4 min), which was higher than that of individual treatment of PAW (0.77 log CFU/mL) or mild heat (1.78 log CFU/mL). The results demonstrated that PAW had good synergistic activity with mild heat against E. coli cells. Field emission scanning electron microscope (FE-SEM) confirmed that the combined treatment with PAW and mild heat caused marked morphological damage of E. coli cells. The N-phenyl-1-napthylamine (NPN) uptake assay and propidium iodide (PI) staining indicated that the combined treatment with PAW and mild heat synergistically enhanced the permeability of the outer and cytoplasmic membrane of E. coli cells, resulting in the leakage of intracellular components such as proteins and nucleic acids. It can be concluded that membrane damage is a key mechanism involved in the inactivation of E . coli cells by the combined treatment with PAW and mild heat. This synergistic antimicrobial treatment of PAW and mild heat may be used as a potential intervention strategy to reduce the incidence of E. coli and other pathogens entering the food chain.
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FOOD CONTROL
·
2019
·
IF 4.248
Yanlan Lin,Xu Tang,Liangzong Xu,Shaoyun Wang
Octopus scraps, as a kind of marine waste, have drawn much attention due to its biological values. Amino groups and carboxyl groups of octopus scraps peptides (OSP) chelated with Zn 2+ formed OSP-Zn by Zn-N and Zn-O covalent bonds. The aggregation state of OSP had been changed and the typical particle diameter of OSP transformed from 104.74 nm to 147.36 nm after chelating with zinc. The chelate OSP-Zn showed notably antimicrobial ability towards Escherichia coli (E. coli). Moreover, the antibacterial mechanism of OSP-Zn against E. coli might be explained by the pathway of damaging cell membrane structure and oxidative stress-mediated apoptosis. It also suggests that OSP-Zn could inhibit the growth of the dominant spoilage bacteria of Penaeus vannamei and exhibit a good preservative effect. Our work illuminates the synergic effect of OSP and Zn complexes for the first time, supporting the potential application of OSP-Zn chelate as a natural bacteriostatic agent in the food or pharmaceutical industry.
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