JOURNAL OF BACTERIOLOGY
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2017
·Vol. 200
·期 1
·
IF 3.143
Hao Yu,Shuxue Zhao,Lizhong Guo
The 1,125-bp mabB gene encoding 5-aminosalicylate (5ASA) 1,2-dioxygenase, a nonheme iron dioxygenase in the bicupin family that catalyzes the cleavage of the 5ASA aromatic ring to form cis-4-amino-6-carboxy-2-oxohexa-3,5-dienoate in the biodegradation of 3-aminobenzoate, was cloned from Comamonas sp. strain QT12 and characterized. The deduced amino acid sequence of the enzyme has low sequence identity with that of other reported ring-cleaving dioxygenases. MabB was heterologously expressed in Escherichia coli cells and purified as a His-tagged enzyme. The optimum pH and temperature for MabB are 8.0 and 10°C, respectively. FeII is required for the catalytic activity of the purified enzyme. The apparent Km and Vmax values of MabB for 5ASA are 52.0 ± 5.6 μM and 850 ± 33.2 U/mg, respectively. The two oxygen atoms incorporated into the product of the MabB-catalyzed reaction are both from the dioxygen molecule. Both 5ASA and gentisate could be converted by MabB; however, the catalytic efficiency of MabB for 5ASA was much higher (∼70-fold) than that for gentisate. The mabB-disrupted mutant lost the ability to grow on 3-aminobenzoate, and mabB expression was higher when strain QT12 was cultivated in the presence of 3-aminobenzoate. Thus, 5ASA is the physiological substrate of MabB.IMPORTANCE For several decades, 5-aminosalicylate (5ASA) has been advocated as the drug mesalazine to treat human inflammatory bowel disease and considered the key intermediate in the xenobiotic degradation of many aromatic organic pollutants. 5ASA biotransformation research will help us elucidate the microbial degradation of these pollutants. Most studies have reported that gentisate 1,2-dioxygenases (GDOs) can convert 5ASA with significantly high activity; however, the catalytic efficiency of these enzymes for gentisate is much higher than that for 5ASA. This study showed that MabB can convert 5ASA to cis-4-amino-6-carboxy-2-oxohexa-3,5-dienoate, incorporating two oxygen atoms from the dioxygen molecule into the product. Unlike GDOs, MabB uses 5ASA instead of gentisate as the primary substrate. mabB is the first reported 5-aminosalicylate 1,2-dioxygenase gene.
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Energy Technology
·
2017
·Vol. 6
·期 9
·1633-1641
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IF 2.789
Fei Li,Guang Zhang,Yinghua Song
Herein, a facile method for constructing acid-base and Cr III species multi-functionalized multi-walled carbon nanotubes (CNTs) catalyst was reported. Acid and base, i.e., −SO 3 H and −NH 2 groups, were first grafted on CNTs to synthesize CNTs−SO 3 H−NH 2 bi-functional catalyst. Then the obtained CNTs−SO 3 H−NH 2 catalyst was further functionalized with Cr III species for further enhancement of acidity. The catalytic activity of fabricated catalysts were systematically studied for the one-pot conversion of cellulose to 5-hydroxymethylfurfural (HMF) in an ionic liquid solvent system. Results indicated that in the one-pot cellulose to HMF reaction, acidic sites were necessary for dissolved cellulose hydrolysis and fructose dehydration process, and the isomerization of glucose to fructose can be regarded as rate determining step. Co-existed base and Lewis acid sites were found to promote glucose isomerization to fructose, and Brønsted acid sites direct the dehydration of reactively formed fructose to HMF. And under the optimal conditions, the highest HMF yield of 40.2 % was achieved by multi-functional CNTs−SO 3 H−NH 2 −Cr III catalyst. Moreover, the fabricated catalyst in this study revealed excellent stability for recycle use in HMF production from cellulose.
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Journal of Environmental Sciences
·
2024
·
IF 5.9
Kaini Ma,Kai Li,Ping Ning,Jiayu Feng,Jiacheng Bao,Lei Shi,Xiangyu Wang,Xin Sun
This study employed a wet impregnation method to synthesize five types of Cu/HZSM-5 adsorbents with Si/Al ratios of 25, 50, 85, 200, and 300, used for the removal of H 2 S in low-temperature, low-oxygen environments. The impact of different Si/Al ratios on the adsorption oxidative performance of Cu 30 /HZSM-5–85 adsorbents was investigated. According to the performance test results, Cu 30 /HZSM-5–85 exhibited the highest breakthrough capacity, reaching 231.75 mg H 2 S/g sorbent . Cu/HZSM-5 sorbent maintains a strong ability to remove H 2 S even under humid conditions and shows excellent water resistance. XRD , BET, and XPS results revealed that CuO is the primary active species, with Cu 30 /HZSM-5–85 having the largest surface area and highest CuO content, providing more active sites for H 2 S adsorption. H 2 -TPR and O 2 -TPD results confirmed that Cu 30 /HZSM-5–85 sorbent exhibits outstanding redox properties and oxygen storage capacity, contributing to excellent oxygen transferability in the molecular sieve adsorption-oxidation process. With notable characteristics such as a large surface area, high desulfurization efficiency, and water resistance, Cu 30 /HZSM-5–85 sorbents hold significant importance for industrial applications.
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Chem Catalysis
·
2024
·
IF 11.5
Bin Chen,Shui Yang,Longmei Shang,Yiling Wu,Youting Wang,Jian Tian,Jiale Huang,Xiaodong Zhang,Qingbiao Li,Guowu Zhan
Biomass resources can be converted to biochemicals via the catalytic pyrolysis process, but conventional catalysts often suffer from severe deactivation due to coke formation. Here, a ternary Ni/bio-Z5 catalyst was constructed by integrating ZSM-5 and Ni components on a porous bio-SiO2 platform derived from rice husk. The Ni/bio-Z5 achieved 76% aromatic selectivity for the catalytic pyrolysis of soybean oil, corresponding to a space-time yield as high as 154.8 garom · h−1 · gcata−1. It is confirmed that the bio-SiO2 platform shortened the surface diffusion path of aromatics by co-diffusion, which then inhibited coke formation and significantly improved the catalyst stability. Moreover, the atomically dispersed Ni on ZSM-5 effectively promotes the aromatization of C2=-C6= by enhancing adsorption and acting as an oligomerization center for isoalkyl carbenium ions. The coupling of deoxygenation and aromatization reactions promotes the enhancement of aromatic selectivity through the formation of methyl-substituted cyclopentenone that can be readily converted to aromatics.
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POWDER TECHNOLOGY
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2024
·
IF 4.5
Han Hao,Tiantian Ren,Cuilu Quan,Jing Wang
Arginine (ARG) is a precursor for producing NO, which can relax vascular smooth muscle. We herein report cocrystals screened by powder grinding using chiral ARG to improve the bioavailability of 5-fluorouracil (5-FU) and alleviate 5-FU induced cardiotoxicity. The results of powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) inferred the formation of new solid phases. Hydrogen bonding interactions between C=O group and N-H were supported by Fourier transform infrared (FTIR) spectroscopy. The spectra intensity of circular dichroism (CD) of cocrystals were higher than that of ARG after combined with non-optically active 5-FU. The bioavailability and cytotoxicity of 5-FU were enhanced by cocrystallization. Notably, L-cocrystal prepared using biologically active L-ARG released lower dose NO in human umbilical vein endothelial cells (HUVEC) cells than that of D-cocrystal. D-cocrystal performed higher NO release ability by non-enzymatic pathway, indicating a greater potential to alleviate cardiotoxicity. 5-FU-induced cardiotoxicity in rats was effectively alleviated, proved by the least increased LDH, cTnI and CK-MB level induced by D-cocrystal.
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Bioresources and Bioprocessing
·
2025
·Vol. 12
·期 1
·1-14
·
IF 5.1
Ai Yulin,Huang Yusong,Zhao Hongru,Su Bingmei,Lin Juan
5-Hydroxytryptophan (5-HTP) is widely used as a natural remedy for sleep disorders. In terms of biosafety, bio-derived 5-HTP is preferred over chemically synthesized 5-HTP. However, the low titer of 5-HTP in the reported microbiological methods (< 10 g/L) limits the industrialization of 5-HTP biosynthesis. In the present study, a Trp-accumulating E. coli strain TRP1 was constructed by blocking the degradation path (Δ tnaA ), branching paths (Δ pheA , Δ tyrA ) and repression system (Δ trpR , Δ trpL ). Next, the hydroxylation module employing a phenylalanine hydroxylase mutant XcPAH W179F (XC2) coupled with an MH4 regenerating system (CvPCD-EcFolM system) was screened to convert L-Trp into 5-HTP. Protein engineering was performed on hydroxylase XC2 based on the molecular dynamics simulation of the enzyme-substrate complex, and the strain TRP1-XC4 harboring the triple-mutant XcPAH L98I/A129K/W179F (XC4) was able to produce 319.4 mg/L 5-HTP. Genome editing was carried out focused on accelerating product efflux (strengthening YddG) and increasing MH4 supply (strengthening FolM, FolE and FolX), resulting in a strain TRP5-XC4 to produce 13.9 g/L 5-HTP in 5 L fed-batch fermentation with a space-time yield of 0.29 g/L/h, which is the highest production and productivity record for 5-HTP biosynthesis. This study successfully provided an engineered strain and an efficient green method for the industrial synthesis of 5-HTP. Graphical
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Journal of Water Process Engineering
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2024
·
IF 6.3
Jing Li,Suxia Ma,Nuo Xu
The pursuit of carbon peaking and carbon neutrality goals necessitates flexible operation and deep peaking of coal-fired units, thus placing heightened demands on nitrogen oxide (NO X ) emission control. Fly ash, a solid waste rich in silicon (Si) and aluminum (Al), should be fully leveraged, and the high-value synthesis of zeolite represents a viable utilization method. In this context, fly ash-based zeolite was prepared as a catalyst to facilitate the generation of active oxides from H 2 O 2 , combined with alkali solution absorption, to achieve efficient denitrification. This approach effectively transforms ‘waste to pollution’ mitigation. The optimal synthesis conditions for FA-ZSM-5 zeolite were established using the alkali fusion hydrothermal synthesis method, with fly ash as the raw material. The specified conditions were NaOH/FA = 1.2, SiO 2 /Al 2 O 3 = 40, H 2 O/Al 2 O 3 = 1325, TPAOH/Al 2 O 3 = 10, ZSM-5-seed addition of 5 %, and a hydrothermal temperature and time of 140 °C for 24 h. Experimental parameters were meticulously investigated to ascertain their impact on nitric oxide (NO) removal efficiency. The highest removal efficiency was achieved under specific conditions: a reaction temperature of 140 °C, an H 2 O 2 concentration of 6 %, a catalyst dose of 0.3 g, an NO concentration of 600 mg/m 3 , and an SO 2 concentration of 1000 mg/m 3 . Finally, analysis of the catalytic oxidation mechanism revealed that H 2 O 2 , when catalyzed by FA-ZSM-5 zeolite, generates ·OH radicals with strong oxidizing properties, thereby facilitating the oxidative removal of NO.
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ACS Nano
·
2024
·
IF 15.8
Hao Zhang,Li Yang,Mengxiao Han,Yaobao Han,Zhilin Jiang,Qing Zheng,Jun Dong,Tingting Wang,Zhen Li
The currently available immune checkpoint therapy shows a disappointing therapeutic efficacy for glioblastoma multiforme (GBM), and it is of great importance to discover better immune checkpoints and develop innovative targeting strategies. The discovered metabolic immune checkpoint ecto-5-nucleotidase (CD73) in a tumor contributes to its immune evasion due to the dysregulation of extracellular adenosine (ADO), which significantly inhibits the function of antitumor T cells and increases the activity of immunosuppressive cells. Herein, we drastically inhibit the expression of CD73 to reduce the production of ADO by using versatile Au@Cu2–xSe nanoparticles (ACS NPs). ACS NPs can decrease the expression of CD73 by alleviating the tumor hypoxia through their Fenton-like reaction to weaken the ADO-driven immunosuppression for enhancing antitumor T cell infiltration and activity of GBM. The copper ions (Cu2+) released from ACS NPs can chelate with disulfide, leading to the formation of cytotoxic bis(N,N-diethyldithiocarbamate)-copper complex (CuET), which can be combined with radiotherapy to recruit more antitumor T cells to infiltrate into the tumor site. Based on the inhibition of CD73 to promote the infiltration and activity of antitumor T cells, a cascade of enhancing GBM immunotherapy effects can be achieved. The significant increase in CD8+ T and CD4+ T cells within the tumor and the memory T cells in the spleen effectively reduces tumor size by 92%, which demonstrates the excellent efficacy of immunotherapy achieved by a combination of metabolic immune checkpoint CD73 inhibition with chemoradiotherapy. This work demonstrates that modulation of CD73-mediated tumor immunosuppression is an important strategy of improving the outcome of GBM immunotherapy.
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Heliyon
·
2024
·
IF 3.4
Changhong Wu,Jie Yang,Chenxiao Ye,Hui Wu,Wenxi Shu,Rongrong Li,Sihan Wang,Yi Lu,Haitao Chen,Zewei Zhang,Qinghua Yao
Background 5-Fluorouracil (5-Fu), a prominent chemotherapeutic agent for colorectal cancer (CRC) treatment, is often associated with gastrointestinal toxicities, particularly diarrhea. Our previous study demonstrated that berberine (BBR) ameliorates 5-Fu-induced intestinal mucosal injury by modulating the gut microbiota in rats. Nevertheless, the precise molecular mechanism underlying BBR's protective effect on intestinal mucosa remains elusive, and its impact on the anti-tumor efficacy of 5-Fu warrants further investigation. Methods The effect of BBR on 5-Fu-induced intestinal mucosal injury was investigated using a tumor-bearing murine model, employing H&E staining, 16 S rDNA sequencing, transcriptome sequencing, Western blot analysis, cell experiments and constructing a pseudo-germ-free tumor xenograft model. Result Our findings demonstrate that BBR alleviates intestinal mucosal damage, reduces the levels of inflammatory factors (IL-6, TNF-α, and IL-1β), and inhibits epithelial cell apoptosis in 5-Fu-treated mice without compromising 5-Fu's anti-tumor efficacy. Moreover, 16 S rDNA sequencing indicated that BBR significantly increases the abundance of Akkermansia and decreases the abundance of pathogenic bacteria Escherichia/Shigella at the genus level. Mechanistically, transcriptome sequencing and Western blot analysis confirmed that BBR upregulates PI3K/AKT/mTOR expression in the intestinal mucosa. However, this effect was not observed in tumor tissues. Notably, BBR did not demonstrate a direct protective effect on 5-Fu-treated CCD841 and SW480 cells. Additionally, BBR had no effect on the PI3K/AKT/mTOR pathway in the intestinal tissue of the 5-Fu-treated mouse model with a depleted gut microbiota. Conclusion This study indicates that BBR alleviates 5-Fu-induced intestinal mucosal injury by modulating the gut microbiota and regulating the PI3K/AKT/mTOR signaling pathway without compromising the anti-tumor efficacy of 5-Fu.
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CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Xiangfei Ding,Youbing Zhu,Ketao Shi,Zhen Xu,Jian Chen,Zengxi Li,Hui Wang
ZSM-5 zeolite is extensively employed for hydrocarbons cracking to generate light olefins, and its acidity is closely related to the activity and product distribution. In this work, Al-Sn bimetallic ZSM-5 was prepared via a “one-pot” route. Characterizations, including XRD, UV–Vis, XPS, revealed that Sn species were mainly embedded into the zeolite framework as tetrahedral Sn (IV). Moreover, the Sn atoms promoted the formation of Lewis acid sites and reduced the Brønsted acid amount, which effectively inhibited occurrence of side reactions ( e.g. , aromatization, hydrogen transfer) and improved the selectivity of light olefins in n-hexane cracking. Light olefins yield over HZ5[100,200] (Si/Al = 100, Si/Sn = 200) reached 33.4 % due to the appropriate acid property, in comparison with only 15.4 % for HZ5[50,∞] (Si/Al = 50, Si/Sn=∞) containing system. Through optimization of reaction conditions, better catalytic performance (n-hexane conversion of 91.6 % and light olefins yield of 37.6 %) was obtained over HZ5[100,200] under 575 °C with WHSV of 2 h −1 .
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Clean Energy
·
2025
·
IF 3.7
Jiang Zhenhua,Xia Wei,Zhang Yanli,Wang Xinrui,Dong Mingyuan,Chen Kun,Liu Dong,Lu Baowang
This study aims to compare the catalytic performance of ZSM-5 and SAPO-34 zeolite catalysts in the conversion of ethanol. Through experiments conducted at different temperatures (773 K and 673 K), it was found that SAPO-34 initially exhibits superior propylene selectivity compared to ZSM-5. However, the propylene yield on SAPO-34 gradually decreases, while the ethylene yield increases with time on stream. density functional theory calculations were employed for the investigation of reaction mechanism. The results indicate that the SAPO-34 catalyst surface favors propylene desorption, which beneficial for its initial high propylene selectivity. Nevertheless, the smaller pore structure of SAPO-34 limits the effective diffusion of products, leading to product accumulation within the pores and potentially causing catalyst coking and deactivation. By combining the experimental results with theoretical calculation, this study not only explored the selectivity difference between SAPO-34 and H-ZSM-5 in ethanol conversion reaction, but also revealed the influence of different molecular sieve catalyst structures on product distribution and catalyst stability.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2024
·
IF 5.7
Yangyang Wen,Jie Li,Weiwei Gong,Zhenjia Yu,Hailin Wang,Shiyi Lu,Hongyan Li,Jing Wang,Baoguo Sun
Precise on-site monitoring of alkylresorcinols, a vital biomarker, is crucial for verifying whole wheat foods and accurately quantifying the whole wheat content in various consumer and industrial products. Herein, for the first time, we introduce a novel ratiometric fluorescence sensor (CDs@ZIF-8/CdTe@MIP) for ultrasensitive and selective detection of alkylresorcinols. 5-Heneicosylresorcinol (C21:0 AR), the primary alkylresorcinol homologue in whole wheat grains, was selected as the target analyte. This analyte was specifically and selectively recognized by the incorporation of a molecularly imprinted polymer (MIP) layer. Within this nanoreactor, blue-emitting carbon dots embedded in zeolitic imidazolate framework-8 (CDs@ZIF-8) and orange-emitting CdTe quantum dots served as the self-calibration signal and response signal, respectively. Exploiting a photoinduced electron transfer effect between CdTe and C21:0 AR, the established fluorescence sensor exhibited remarkable sensing performance, offering wide linear responses in 0.005–1 μg·mL–1 and 1–80 μg·mL–1 concentration ranges, and achieving a low detection limit of 1.14 ng·mL–1. The proposed assay effectively detected C21:0 AR in real samples, including 8 whole wheat foods and 19 whole wheat grains, demonstrating good recoveries and relative standard deviation. Furthermore, an intelligent sensing platform was established by integrating CDs@ZIF-8/CdTe@MIP with a smartphone-assisted device, thus validating the feasibility of visual and on-site monitoring of C21:0 AR. Because of its rapid response, portability, cost-effectiveness, superior sensitivity, and high selectivity, the proposed sensor serves as a reliable method for the analysis of C21:0 AR, thus having substantial potential for on-site monitoring of whole wheat foods.
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