MICROBIAL PATHOGENESIS
·
2024
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IF 3.3
Xiaoye Cheng,Yijin Jiang,Xu Zhao,Nana Ma,Xiangzhen Shen
Lactate has been increasingly recognized for its role in diseases progression, necessitating a deeper understanding of its metabolic processes and regulatory mechanisms. This study aimed to evaluate the impact of lipopolysaccharide (LPS) on lactate accumulation in bovine mammary epithelial cells (BMECs) and to elucidate the underlying regulatory mechanisms. Further optimization of LPS treatment points was achieved by assessing the content of key glycolytic enzymes-hexokinases (HK), pyruvate kinase (PK) and pyruvate dehydrogenase (PDH)-as well as the expression levels of HK2, pyruvate dehydrogenase kinase4 (PDK4) and lactate dehydrogenase (LDHA). Our results indicate that LPS can promote intracellular glycolysis and inhibits pyruvate synthesis, thereby increasing lactate content. BMECs were cultured and divided into a control group (CON) and an LPS-stimulated group (10 μg/mL for 6 h, LPS group). LPS was found to upregulate expression levels of HIF-1α and MCT1, suggesting a role for HIF-1α and MCT1 in cellular glucose metabolism. To explore the effect of HIF-1α on lactate accumulation, BMECs were stimulated with a HIF-1α inducer (COCL 2 ) and HIF-1α inhibitor (DMBPA). COCL 2 was observed to promote lactate accumulation, while DMBPA inhibited it. Additionally, modulation of HIF-1α expression influenced the expression of MCT1, which is a crucial transporter for extracellular lactate influx. To investigate the specific impact of MCT1 on intracellular lactate, we utilized overexpression plasmids and small interfering RNA to modulate MCT1 expression. The findings indicate that while MCT1 expression alone does not affect intracellular lactate levels, it does modulate the changes induced by LPS. In conclusion, our study suggests that LPS regulates lactate accumulation in BMECs through the HIF-1α/MCT1 pathway, providing insights into the metabolic dysregulation associated with LPS-induced stress in dairy cattle.
研究领域:
动物科学
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细胞生物学
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代谢学
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乳品科学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF BIOTECHNOLOGY
·
2024
·
IF 4.1
Kehao Yuan,Zongchao Huo,Ya`ning Zhang,Zuran Guo,Yucan Chang,Yunming Jin,Lining Gao,Tong Zhang,Yanwei Li,Qinyuan Ma,Xiuzhen Gao
During the deamination and amination processes of meso -diaminopimelate dehydrogenase ( meso -DAPDH) from Symbiobacterium thermophilum (StDAPDH), residue R71 was observed to display distinct functions. H154 has been proposed as a basic residue that facilitates water molecules to attack the D-chiral carbon of meso -DAP during deamination . Inspired by the phenomenon of R71, the effects of H154 during deamination and amination were investigated in this study with the goal of enhancing the amination activities of StDAPDH. Single site saturation mutagenesis indicated that almost all of the H154 mutants completely lost their deamination activity towards meso -DAP. However, some H154 variants showed enhanced k cat / K m values towards pyruvic acid and other bulky 2-keto acids, such as 2-oxovaleric acid, 4-methyl-2-oxopentanoic acid, 2-ketobutyric acid, and 3-methyl-2-oxobutanoic acid. When combined with the previously reported W121L/H227I mutant, triple mutants with significantly improved k cat / K m values (2.4-, 2.5-, 2.5-, and 4.0-fold) towards these 2-keto acids were obtained. Despite previous attempts, mutations at the H154 site did not yield the desired results. Moreover, this study not only recognizes the distinctive impact of H154 on both the deamination and amination reactions, but also provides guidance for further high-throughput screening in protein engineering and understanding the catalytic mechanism of StDAPDH.
研究领域:
生物化学
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蛋白质工程
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酶学
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产品关联
DOI
PubMed
高影响因子
ANNALS OF CLINICAL AND LABORATORY SCIENCE
·
2017
·Vol. 47
·期 6
·676-686
·
IF 0.727
Mingxiu Guan,Yingna Tong,Xiaobin Liu,Dong Dong,Yunli Zhou
Background M2 type Pyruvate kinase (PKM2) is the key rate-limiting enzyme of glycolysis, and it mainly exists as a dimer in tumor cells.This study aims to establish an enzyme kinetic assay for serum tumor M2 pyruvate kinase (TuM2-PK), and to evaluate its diagnosticvalue in breast cancer. Methods The catalytic kinetics of Pyruvate Kinase (PK) was examined. Its allosteric regulation property and Michaelis constant werethen measured. Next, the levels of TuM2-PK in serum were detected and compared with results from an enzyme-linked immunosorbentassay (ELISA). Finally, the levels of TuM2-PK among breast cancer patients, post-mastectomy patients, patients with benignbreast diseases, and healthy controls were compared. Results A PK kinetic assay was established in this study. The assay reaction time is 108 seconds, and the optimum pH level is 8.0.In the presence of the allosteric activator fructose 1, 6-bisphosphate (FBP), the Km of PK for phosphoenolpyruvate (PEP) is0.15 mmol/L and the Vmax is 330 μmol/min. The levels of TuM2-PK in serum obtained by enzyme kinetics are comparable to theELISA results. Both assays showed that TuM2-PK in breast cancer patients was increased from stage I to IV. Importantly, TuM2-PKlevels were significantly different between early and late-stage breast cancer patients (stage I and stage II vs. stage IIIand IV), as well as between late-stage and non-malignant patients (p<0.05). No statistical difference was found between benign breast disease patients and healthy controls. Conclusions An enzyme kinetic assay of serum TuM2-PK was successfully established and may be useful for breast cancer diagnosis.
研究领域:
肿瘤学
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生物化学
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癌症诊断
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酶学
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产品关联
DOI
PubMed
高影响因子
Biomolecules
·
2021
·Vol. 11
·期 9
·1358
·
IF 4.879
Li Liu,Bohao Wang,Sheng Li,Fengyuan Xu,Qi He,Chun Pan,Xiangdong Gao,Wenbing Yao,Xiaoda Song
The activity and function of proteins can be improved by incorporation of non-canonical amino acids (ncAAs). To avoid the tedious synthesis of a large number of chiral phenylalanine derivatives, we synthesized the corresponding phenylpyruvic acid precursors.Escherichia colistrain DH10B and strain C321.ΔA.expΔPBAD were selected as hosts for phenylpyruvic acid bioconversion and genetic code expansion using theMmPylRS/pyltRNACUAsystem. The concentrations of keto acids, PLP and amino donors were optimized in the process. Eight keto acids that can be biotransformed and their coupled genetic code expansions were identified. Finally, the genetic encoded ncAAs were tested for incorporation into fluorescent proteins with keto acids.Keywords:keto acids;biotransform;evolution
研究领域:
生物化学
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分子生物学
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合成生物学
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DOI
PubMed
高影响因子
EBioMedicine
·
2018
·
IF 6.183
Aiyun Li,Qun Liu,Qiang Li,Baolin Liu,Yang Yang,Ning Zhang
Background Mitochondrial pyruvate import via mitochondrial pyruvate carrier (MPC) is a central step in hepatic gluconeogenesis. Berberine inhibits hepatic gluconeogenesis, but the mechanism is incompletely understood. This study aims to investigate whether berberine could reduce excessive hepatic glucose production (HGP) by limiting mitochondrial import of pyruvate through MPC1. Methods High-fat diet (HFD) feeding augmented HGP. The effects of berberine on hepatic fatty acid oxidation, sirtuin3 (SIRT3) induction and mitochondrial pyruvate carrier 1 (MPC1) function were examined. Findings HFD feeding increased hepatic acetyl coenzyme A (acetyl CoA) accumulation with impaired pyruvate dehydrogenase (PDH) activity and increased pyruvate carboxylase (PC) induction. Berberine reduced acetyl CoA accumulation by limiting fatty acid oxidation and prevented mitochondrial pyruvate shift from oxidation to gluconeogenesis through carboxylation. Upon pyruvate response, SIRT3 binded to MPC1 and stabilized MPC1 protein via deacetylation modification, facilitating mitochondrial import of pyruvate. Berberine preserved the acetylation of MPC1 by suppression of SIRT3 induction and impaired MPC1 protein stabilization via protein degradation, resultantly limiting mitochondrial pyruvate supply for gluconeogenesis. Interpretation Berberine reduced acetyl CoA contents by limiting fatty acid oxidation and increased MPC1 degradation via preserving acetylation, thereby restraining HGP by blocking mitochondrial import of pyruvate. These findings suggest that limitation of mitochondrial pyruvate import might be a therapeutic strategy to prevent excessive hepatic glucose production.
研究领域:
药理学
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代谢学
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肝病学
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分子生物学
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产品关联
DOI
PubMed
高影响因子
Inorganic Chemistry Frontiers
·
2023
·Vol. 10
·期 15
·4562-4568
·
IF 7
Chu-Xuan Liu,Rui Shi,Wangjing Ma,Fulai Liu,Yong Chen
The recycling of plastic waste has attracted increasing attention because of its negative effects on the ecological environment and human health. Photoreforming is emerging as a green and promising approach for upcycling plastic waste into highly valuable chemicals and H2 fuels. Herein, an earth-abundant Ni2P/ZnIn2S4 catalyst prepared by mechanical grinding is reported to selectively photoreform various polyester plastics into high-added-value chemicals coupled with H2 evolution under mild conditions. In particular, polylactic acid (PLA) can be upcycled to pyruvic acid (PA) with high activity (745.9 μmol g−1 h−1) and selectivity (>90%). Moreover, the H2 evolution rate can reach up to 781.3 μmol g−1 h−1 catalyzed by 7.5 wt% Ni2P/ZnIn2S4. This system exhibits excellent photocatalytic performance, benefiting from efficient photogenerated charge carrier separation and transfer between Ni2P and ZnIn2S4. This study provides a viable and promising solution for simultaneously producing high-purity H2 and added-value chemicals from polyester plastic waste, demonstrating its potential for practical recycling applications.
研究领域:
环境科学
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材料科学
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化学工程
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2020
·
IF 5.774
Yan Li,Jian-Ying Dai,Zhi-Long Xiu
The salting-out extraction (SOE) systems based on ionic liquids (ILs) have attracted extensive attention in the separation of bio-based products, in which imidazolium ILs were widely studied. However, the high cost and toxicity have hindered their further industrial application. Hydroxylammonium ILs have the characteristics of cheap raw material, simple synthesis process and low toxicity, but are rarely used in the SOE systems. In this work, five hydroxylammonium ILs (2 cations and 4 carboxylate anions) were synthesized and used in SOE of bio-chemicals. The phase forming abilities of ILs with K 3 PO 4 and H 2 O were affected by the hydrophilicity of anions and cations. With the increase of carbon chain length, phase forming abilities of ILs increased, while the temperature had little influence. The partition behaviors of acetoin, ILs and 2,3-butandiol, and the selectivity of acetoin to organic acids were investigated and compared at different concentrations of ethanolammonium butyrate (EOAB) and K 3 PO 4 . In a SOE system consisted of 6% EOAB-38% K 3 PO 4 (w/w), the recovery of acetoin, IL and 2,3-butandiol was 92.7%, 76.0% and 86.0%, respectively, and the selectivity of acetoin to lactic acid and acetic acid was 16.46 and 3.85, respectively. The ATR-IR spectra showed the hydrogen bonds formed between acetoin and O-H, N-H, –COO – of hydroxylammonium IL played an important role in the efficient extraction of acetoin from fermentation broths.
研究领域:
生物化工
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化学工程
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产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2023
·
IF 4.2
Yiyun Wang,Xinli Li,Zhi Chen,Kai Ma,Congming Tang
This work reported the coupling reaction of lactic acid (LA) to produce pyruvic acid (PyA) and propionic acid (PA) simultaneously over defect-rich MoS2 nanosheets. The process intensification linked to dehydrogenation of LA and hydrodeoxygenation of LA brings about the advantage that is not supplied additionally with oxygen and hydrogen, achieving a green and safe route. The defected structure is characterized by high-resolution transmission electron microscopy (HRTEM) and positron annihilation lifetime spectroscopy (PALS), which promotes the catalytic performance for the coupling reaction of LA. To fully understand the importance of the defected structure, the catalytic performance of defect-free MoS2 is also evaluated. It is found that the PyA/PA ratio is less than 1 and acetaldehyde selectivity is relatively high, suggesting that the produced hydrogen from the dehydrogenation of LA is insufficient for hydrodeoxygenation of LA over defect-free MoS2, and the difference of hydrogen comes from the side reactions of decarbonylation and decarboxylation of LA. Unlike the defect-free MoS2, the dehydrogenation of LA over the defect-rich MoS2 can provide sufficient hydrogen for hydrodeoxygenation of LA, so that the side reactions are drastically weakened. The widened interplanar spacing can fully expose the defect and the LA reactant molecule is more accessible to defective sites, which can endow a better catalytic activity. Surface hydrophilicity can improve adsorption and transfer, and better activity is observed over the defect-rich MoS2 and widened defect-rich MoS2. At 300 °C and a LA LHSV of 2.6 h–1 under an inert atmosphere, the catalyst offers a satisfactory total selectivity to pyruvic acid and propionic acid of about 85%, and the molar ratio of pyruvic acid/propionic acid is 1.1.
研究领域:
化学工程
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催化科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Lu Li,Sihong Xu,Liang Jin,Wenxing Chen,Shichang Chen
It is essential to find a depolymerization system with good catalytic activity, easy operation, and high efficiency for the degradation of waste PET. The synergistic catalytic effect of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and zinc 2-ethylhexanoate (ZnEH) in PET glycolysis was investigated. Waste PET can be more efficient when completely degraded than single organocatalyst or zinc salt or previous DBU/Zn(OAc) 2 , and the yield of BHET reaches 84.1 % under optimal reaction conditions with the molar ratio of 2:1 of DBU to ZnEH and the weight ratio of 3:1 of EG to PET, the temperature of 180 °C and at 60 minutes. By combining experimental results with density functional theory (DFT) calculations, the synergistic enhancing degradation mechanism that generates hydrogen and coordination bonds is proposed. The purified depolymerization product of BHET was repolymerized to PET, delightfully the r-PET was almost identical to virgin PET.
研究领域:
材料科学
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环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
BIOCHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 3.7
Ying Li,Yu Zeng,Shuo Zhao,Zhen Wang,Li Chen,Kequan Chen
Pyruvate, a pivotal metabolite in the glycolytic pathway, typically confronts substantial barriers to its natural accumulation within microbial cells. This study successfully facilitated the natural accumulation of pyruvate in Actinobacillus succinogenes 130Z by fine-tuning the oxidation-reduction potential (ORP) in the fermentation milieu. A mechanistic exploration revealed that the accumulation of pyruvate was optimized when ORP conditions favorably modulated pyruvate kinase activity and concurrently suppressed succinate dehydrogenase activity. By integrating the influence of metal ions on enzymatic functions with an innovative aluminum ion-mediated ORP control strategy, we achieved a pyruvate yield of 27.54 g/L over 20 hours, which constitutes an 89.54% increase compared to the baseline. Additionally, the production rate of pyruvate reached 1.38 g/L·h. This investigation not only elucidates the metabolic underpinnings that facilitate the natural enrichment of glycolytic intermediates in Actinobacillus succinogenes 130Z but also lays a robust theoretical foundation for the industrial-scale fermentation of pyruvate. Moreover, the capability to efficiently and rapidly concentrate essential platform metabolites within the glycolytic pathway is of paramount significance, potentially propelling forward the research and synthesis of various downstream metabolic products.
研究领域:
微生物学
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生物化学
·
工业发酵
✓ 已验证
DOI
高影响因子
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
·
2020
·Vol. 86
·期 19
·
IF 4.016
Haixia Wang,Xiaoyu Wang,Hao Ren,Xuejun Wang,Zhenmei Lu
3-Hydroxypyridine (3HP) is an important natural pyridine derivative. Ensifer adhaerens HP1 can utilize 3HP as its sole sources of carbon, nitrogen, and energy to grow, but the genes responsible for the degradation of 3HP remain unknown. In this study, we predicted that a gene cluster, designated 3hpd, might be responsible for the degradation of 3HP. The analysis showed that the initial hydroxylation of 3HP in E. adhaerens HP1 was catalyzed by a four-component dehydrogenase (HpdA1A2A3A4) and led to the formation of 2,5-dihydroxypyridine (2,5-DHP). In addition, the SRPBCC component in HpdA existed as a separate subunit, which is different from other SRPBCC-containing molybdohydroxylases acting on N-heterocyclic aromatic compounds. Moreover, the results demonstrated that the phosphoenolpyruvate (PEP)-utilizing protein and pyruvate-phosphate dikinase were involved in the HpdA activity, and the presence of the gene cluster 3hpd was discovered in the genomes of diverse microbial strains. Our findings provide a better understanding of the microbial degradation of pyridine derivatives in nature and indicated that further research on the origin of the discovered four-component dehydrogenase with a separate SRPBCC domain and the function of PEP-utilizing protein and pyruvate-phosphate dikinase might be of great significance.IMPORTANCE 3-Hydroxypyridine is an important building block for the synthesis of drugs, herbicides, and antibiotics. Although the microbial degradation of 3-hydroxypyridine has been studied for many years, the molecular mechanisms remain unclear. Here, we show that 3hpd is responsible for the catabolism of 3-hydroxypyridine. The 3hpd gene cluster was found to be widespread in Actinobacteria, Rubrobacteria, Thermoleophilia, and Alpha-, Beta-, and Gammaproteobacteria, and the genetic organization of the 3hpd gene clusters in these bacteria shows high diversity. Our findings provide new insight into the catabolism of 3-hydroxypyridine in bacteria.
研究领域:
微生物学
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生物化学
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分子生物学
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Zhihao Shen,Qicheng Feng,Shuming Wen,Han Wang
Novel eco-friendly organic depressants with high selectivity are attracting ever-growing interests. The selective inhibition effect of pyrogallic acid (PA) on galena in chalcopyrite flotation was investigated in this study. Flotation trials showed that PA markedly depressed galena with only a small effect on chalcopyrite, which contributed to the separation of chalcopyrite and galena by flotation after adding a low dosage of PA. Surface hydrophobicity tests suggested that PA strongly adsorbed on galena but not on chalcopyrite, which attenuated the adsorption activity of collector on galena, thus rendering galena highly hydrophilic. Conversely, chalcopyrite still retained favorable floatability. These findings were corroborated by the results obtained from infrared and surface adsorption measurements. Results of time-of-flight secondary ion mass spectrometry and X-ray photoelectron spectroscopy measurements also validated the strong adsorption of PA on galena. This behavior promoted the generation of other hydrophilic species on galena. In addition, molecular dynamic simulations demonstrated that PA tended to adsorb on galena, and water molecules accumulated on galena following PA adsorption, which would decrease the floatability of galena.
研究领域:
矿物加工工程
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计算化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）