CHEMOSPHERE
·
2024
·
IF 8.1
Hong-Peng Shi,Ying-Hao Zhao,Mei-Lin Zheng,Cheng-Yan Gong,Lei Yan,Ying Liu,Yong-Ming Luo,Zhi-Pei Liu
The performance of bacterial strains in executing degradative functions under the coexistence of heavy metals/heavy metal-like elements and organic contaminants is understudied. In this study, we isolated a fluorene-degrading bacterium, highly arsenic-resistant, designated as strain 2021, from contaminated soil at the abandoned site of an old coking plant. It was identified as a member of the genus Rhodococcus sp. strain 2021 exhibited efficient fluorene-degrading ability under optimal conditions of 400 mg/L fluorene, 30 °C, pH 7.0, and 250 mg/L trivalent arsenic. It was noted that the addition of arsenic could promote the growth of strain 2021 and improve the degradation of fluorene – a phenomenon that has not been described yet. The results further indicated that strain 2021 can oxidize As 3+ to As 5+ ; here, approximately 13.1% of As 3+ was converted to As 5+ after aerobic cultivation for 8 days at 30 °C. The addition of arsenic could greatly up-regulate the expression of arsR / A / B / C / D and pcaG / H gene clusters involved in arsenic resistance and aromatic hydrocarbon degradation; it also aided in maintaining the continuously high expression of cstA that codes for carbon starvation protein and prmA / B that codes for monooxygenase. These results suggest that strain 2021 holds great potential for the bioremediation of environments contaminated by a combination of arsenic and polycyclic aromatic hydrocarbons. This study provides new insights into the interactions among microbes, as well as inorganic and organic pollutants.
研究领域:
环境微生物学
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生物修复
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毒理学
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分子生物学
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产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2019
·
IF 4.784
Zhang Yajuan,Duan Yajuan,Zhong Lingli,Li Zhoukun,Cui Zhongli,Huang Yan
The asymmetric reduction of prochiral ketones is a promising process for synthesis of optically active alcohols. The aldo-keto reductase (AKR) is an attractive candidate of biocatalyst, due to its high enantioselectivity and environmentally friendly reaction conditions. In this work, nine putative AKR encoding genes from Corallococcus sp. EGB were cloned and expressed in Escherichia coli . Of these produced enzymes (CoAKRs), CoAKR7 exhibited reductive activity to various ketones and ketoesters, especially very high activity toward ethyl 4-chloro-3-oxobutanoate (COBE) with NADPH as the coenzyme. The CoAKR7 was optimally active at pH 7.0 and 50 °C. The apparent K m and V max for COBE was 14.18 U/mg and 0.269 mM, respectively. Moreover, CoAKR7 catalyzed an anti-Prelog reduction of COBE to ( S )-ethyl-4-chloro-3-hydroxybutanoate (CHBE) with e.e. >99%. Enzyme-substrate-cofactor docking analysis elucidated the molecular mechanism of the substrate stereospecificity, providing basis for protein engineering of these enzymes for applications in the synthesis of valuable chemicals.
研究领域:
生物化学
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生物技术
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酶学
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产品关联
DOI
PubMed
高影响因子
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
·
2022
·Vol. 88
·期 4
·
IF 5.005
Zhijian Ke,Qian Zhu,Siyuan Gao,Mingliang Zhang,Mingli Jiang,Yijun Ren,Yali Liu,Yidong Zhou,Jiguo Qiu,Qing Hong
Previously, a LysR family transcriptional regulator, McbG, that activates the mcbBCDEF gene cluster involved in the upstream pathway (from carbaryl to salicylate) of carbaryl degradation in Pseudomonas sp. strain XWY-1 was identified by us (Z. Ke, Y. Zhou, W. Jiang, M. Zhang, et al., Appl Environ Microbiol 87:e02970-20, 2021, https://doi.org/10.1128/AEM.02970-20). In this study, we identified McbH and McbN, which activate the mcbIJKLM cluster (responsible for the midstream pathway, from salicylate to gentisate) and the mcbOPQ cluster (responsible for the downstream pathway, from gentisate to pyruvate and fumarate), respectively. They both belong to the LysR family of transcriptional regulators. Gene disruption and complementation study reveal that McbH is essential for transcription of the mcbIJKLM cluster in response to salicylate and McbN is indispensable for the transcription of the mcbOPQ cluster in response to gentisate. The results of electrophoretic mobility shift assay (EMSA) and DNase I footprinting showed that McbH binds to the 52-bp motif in the mcbIJKLM promoter area and McbN binds to the 58-bp motif in the mcbOPQ promoter area. The key sequence of McbH binding to the mcbIJKLM promoter is a 13-bp motif that conforms to the typical characteristics of the LysR family. However, the 12-bp motif that is different from the typical characteristics of the LysR family regulator binding site sequence is identified as the key sequence for McbN to bind to the mcbOPQ promoter. This study revealed the regulatory mechanisms for the midstream and downstream pathways of carbaryl degradation in strain XWY-1 and further our knowledge of (and the size of) the LysR transcription regulator family.IMPORTANCE The enzyme-encoding genes involved in the complete degradation pathway of carbaryl in Pseudomonas sp. strain XWY-1 include mcbABCDEF, mcbIJKLM, and mcbOPQ. Previous studies demonstrated that the mcbA gene, responsible for hydrolysis of carbaryl to 1-naphthol, is constitutively expressed and that the transcription of mcbBCDEF was regulated by McbG. However, the transcription regulation mechanisms of mcbIJKLM and mcbOPQ have not been investigated yet. In this study, we identified two LysR-type transcriptional regulators, McbH and McbN, which activate the mcbIJKLM cluster (responsible for the degradation of salicylate to gentisate) and the mcbOPQ cluster (responsible for the degradation of gentisate to pyruvate and fumarate), respectively. The 13-bp motif is critical for McbH to bind to the promoter of mcbIJKLM, and 12-bp motif different from the typical characteristics of the LysR-type transcriptional regulator (LTTR) binding sequence affects the binding of McbN to the promoter. These findings help to expand the understanding of the regulatory mechanism of microbial degradation of carbaryl.
研究领域:
微生物学
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分子生物学
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环境科学
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产品关联
DOI
PubMed
高影响因子
Scientific Reports
·
2019
·Vol. 9
·期 1
·1-14
·
IF 4.011
Zhang Yan,Shi Junling,Ni Yongqing,Liu Yanlin,Zhao Zhixia,Zhao Xixi,Gao Zhenhong
Phomopsis sp. XP-8, an endophytic fungus from the bark of Tu-Chung ( Eucommia ulmoides Oliv) showed capability to biosynthesize pinoresinol (Pin) and pinoresinol diglucoside (PDG) from glucose (glu) and phenylalanine (Phe). To verify the mass flow in the biosynthesis pathway, [ 13 C 6 ]-labeled glu and [ 13 C 6 ]-labeled Phe were separately fed to the strain as sole substrates and [ 13 C 6 ]-labeled products were detected by ultra-high-performance liquid chromatography-quadrupole time of flight mass spectrometry. As results, [ 13 C 6 ]-labeled Phe was incorporated into [ 13 C 6 ]-cinnamylic acid (Ca) and p -coumaric acid ( p -Co), and [ 13 C 12 ]-labeled Pin, which revealed that the Pin benzene ring came from Phe via the phenylpropane pathway. [ 13 C 6 ]-Labeled Ca and p -Co, [ 13 C 12 ]-labeled Pin, [ 13 C 18 ]-labeled pinoresinol monoglucoside (PMG), and [ 13 C 18 ]-labeled PDG products were found when [ 13 C 6 ]-labeled glu was used, demonstrating that the benzene ring and glucoside of PDG originated from glu. It was also determined that PMG was not the direct precursor of PDG in the biosynthetic pathway. The study identified the occurrence of phenylalanine- lignan biosynthesis pathway in fungi at the level of mass flow.
研究领域:
生物化学
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代谢组学
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植物次生代谢
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DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2023
·Vol. 30
·期 36
·85558-85568
·
IF 5.8
Jin
Jingnan,Shi Yahui,Zhang Baozhong,Wan Dongjin,Zhang Qingye
A bacterial strain Citrobacter sp. HJS-1 was discovered from the sludge in a drainage canal of a coal mine. Firstly, its biodegradation capacity for benzo[a]pyrene (BaP) was detected under different concentrations. The results proved that the strain possessed excellent biodegradation capacity for BaP with high-efficiency degradation rates ranging from 78.9 to 86.8%. The highest degradation rate was observed in the low-concentration sample, and the high-concentration BaP had a slight influence on the biodegradation capacity due to the potential toxicity of BaP and its oxygen-containing derivatives. Meanwhile, the degradation test for the other five aromatic hydrocarbons (2- to 4-ring) proved that the strain had a comprehensive degradation potential. To clarify the biodegradation mechanism of BaP, a dioxygenase structure was constructed by homology modeling. Then, the interactions between dioxygenase and BaP were researched by molecular simulation. Combined with the identification of the vital BaP-cis-7,8-dihydrodiol intermediate and the interaction analysis, the initial oxidation mode and the binding site of BaP were revealed in the dioxygenase. Taken together, this study has offered a way to understand the biodegradation process of BaP and its interaction mechanism based on experimental and theoretical analysis.
研究领域:
环境微生物学
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生物化学
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分子生物学
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DOI
PubMed
高影响因子
APPLIED AND ENVIRONMENTAL MICROBIOLOGY
·
2024
·Vol. 90
·期 8
·
IF 3.9
Yating Li,Tong Xu,Yanqin Tu,Tong Li,Yifeng Wei,Yan Zhou
Phloroglucinol (1,3,5-trihydroxybenzene) is a key intermediate in the degradation of polyphenols such as flavonoids and hydrolysable tannins and can be used by certain bacteria as a carbon and energy source for growth. The identification of enzymes that participate in the fermentation of phloroglucinol to acetate and butyrate in Clostridia was recently reported. In this study, we present the discovery and characterization of a novel metabolic pathway for phloroglucinol degradation in the bacterium Collinsella sp. zg1085, from marmot respiratory tract. In both the Clostridial and Collinsella pathways, phloroglucinol is first reduced to dihydrophoroglucinol by the NADPH-dependent phloroglucinol reductase (PGR), followed by ring opening to form (S)-3-hydroxy-5-oxohexanoate by a Mn2+-dependent dihydrophloroglucinol cyclohydrolase (DPGC). In the Collinsella pathway, (S)-3-hydroxy-5-oxohexanoate is then cleaved to form malonate semialdehyde and acetone by a newly identified aldolase (HOHA). Finally, a NADP+-dependent malonate-semialdehyde dehydrogenase converts malonate semialdehyde to CO2 and acetyl-CoA, an intermediate in carbon and energy metabolism. Recombinant expression of the Collinsella PGR, DPGC, and HOHA in E. coli enabled the conversion of phloroglucinol into acetone, providing support for the proposed pathway. Experiments with Olsenella profusa, another bacterium containing the gene cluster of interest, show that the PGR, DPGC, HOHA, and MSDH are induced by phloroglucinol. Our findings add to the variety of metabolic pathways for the degradation of phloroglucinol, a widely distributed phenolic compound, in the anaerobic microbiome.
研究领域:
微生物学
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生物化学
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代谢途径
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酶学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2022
·
IF 14.224
Qingyun Ma,Xiaoyan Han,Jinlong Song,Jie Wang,Qingqing Li,Rebecca E. Parales,Lin Li,Zhiyong Ruan
The widespread use of the herbicide chlorimuron-methyl is hazard to rotational crops and causes soil degradation problems. Biodegradation is considered a promising way for removing herbicide residues from the environment. Here, a new isolated strain, Cedecea sp . LAM2020, enabled complete degradation of 100 mg/L chlorimuron-methyl within five days. Transcriptome analysis revealed that ABC transporters, atrazine degradation and purine metabolism were enriched in the KEGG pathway. Integrating GO and KEGG classification with related reports, we predict that carboxylesterases are involved in the biodegradation of chlorimuron-methyl by LAM2020. Heterologous expression of the carboxylesterase gene carH showed 26.67% degradation of 50 mg/L chlorimuron-methyl within 6 h. The intracellular potential biological response and extracellular degradation process of chlorimuron-ethyl were analyzed by the nontarget metabolomic and mass spectrometry respectively, and the biodegradation characteristics and complete mineralization pathway was revealed. The cleavage of the sulfonylurea bridge and the ester bond achieved the first step in the degradation of chlorimuron-methyl. Together, these results reveal the presence of acidolysis and enzymatic degradation of chlorimuron-methyl by strain LAM2020. Hydroponic corn experiment showed that the addition of strain LAM2020 alleviated the toxic effects of chlorimuron-ethyl on the plants. Collectively, strain LAM2020 may be a promising microbial agent for plants chlorimuron-ethyl detoxification and soil biofertilizer .
研究领域:
环境微生物学
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生物修复
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植物科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Cleaner Production
·
2024
·
IF 9.7
Jin-Na Zhang,Xiao-Fan Gong,Guang-guo Ying,An-Guo Wang,Mei-Jun Dong,You-sheng Liu,Tong-Chu Deng,Mei-Ying Xu
In response to the widespread environmental concern of endocrine disruptors, our research investigated the aerobic biodegradation of dexamethasone (DEX), a widely used synthetic glucocorticoid with endocrine-disrupting properties, by strain Rhodococcus sp. D32. This innovative strain showcases remarkable DEX-degrading capabilities, with the half-life for degrading 500 μg/L DEX in MH broth being just 7.56 h. Utilizing high-resolution mass spectrometry, we identified six transformation products (TPs) and revealed a unique steroid nucleus-opening pathway marked by A-ring lactonization and subsequent lactone hydrolysis. This newly discovered pathway deviates from the classical steroid 9,10-seco pathways and previous transformations that preserved the intact steroid nucleus, thus expanding our knowledge of microbial steroid transformations. Additionally, the degradation process progressively converts the parent DEX into less ecotoxic products, significantly reducing the overall ecotoxicity of the system. This reduction remains evident when considering the combined toxicity of DEX and its TPs, indicating a promising approach for lessening environmental harm. Strain D32 also proved effective in various authentic aquatic environments, including fishpond water, urban sewage, river water, and reservoir water, where its introduction markedly expedited the dissipation of DEX. Our findings underscore the potential of strain D32 as a powerful tool for the bioremediation of DEX, presenting an efficient and eco-friendly strategy to alleviate the effects of this endocrine disruptor in aquatic ecosystems.
研究领域:
环境科学
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微生物学
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生物技术
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毒理学
✓ 已验证
DOI
高影响因子
JOURNAL OF APPLIED MICROBIOLOGY
·
2019
·Vol. 127
·期 6
·1716-1726
·
IF 2.683
Cheng R.,Wang L.,Li J.,Fu R.,Wang S.,Zhang J.
AimsTo purify and characterize an exopolysaccharide (EPS) from an Agrobacterium strain ZCC3656 with high EPS‐secreting performance and investigate its anti‐inflammatory activity using lipopolysaccharide (LPS)‐induced macrophage cells in an acute liver injury mouse model.Methods and ResultsTwelve rhizobial strains were compared for EPS fermentation production in modified M9 salts supplemented with mannitol or sucrose as the sole carbon source. Agrobacterium sp. ZCC3656 exhibited the highest EPS yield (21·1 g l−1) and was characterized for EPS production by carbon source utilization, time course fermentation and serial subcultivation assays. The EPS, designated Riclin, was purified by deproteinization using the Sevag method. The combined results of gel permeation chromatography, monosaccharide composition, methylation analysis and nuclear magnetic resonance analyses indicated that Riclin is a succinoglycan‐like polysaccharide comprised of glucose, galactose, succinate and pyruvate at a ratio of 7·8. : 1·0 : 0·9 : 1·1 and has an molecular weight of approximately 2·5 × 106 Da. Riclin inhibited TNF‐α, IL‐1β and IL‐6 expression in LPS‐stimulated RAW 264.7 macrophage cells in a dose‐dependent manner. In addition, Riclin pretreatment increased the survival rate of D‐Gal/LPS treated mice, inhibited serum ALT and AST activities and reduced the production of the inflammatory mediators TNF‐α, IL‐1β and IL‐6.ConclusionsAgrobacterium sp. ZCC3656 is a highly stable EPS‐producing strain. The EPS Riclin from ZCC3656 is a succinoglycan‐type polysaccharide that is noncytotoxic and exhibits remarkable anti‐inflammatory effects in vivo and in vitro.Significance and Impact of the StudySuccinoglycans are well known for good rheological properties and their physiological interactions with plants. However, their potential activity towards mammals has received little attention. Our study revealed that the succinoglycan Riclin exhibited excellent anti‐inflammatory activities and could be considered as a promising reagent in anti‐inflammatory treatment.
研究领域:
微生物学
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免疫学
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药理学
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产品关联
DOI
PubMed
高影响因子
FOOD CHEMISTRY
·
2021
·
IF 7.514
Ruiguo Cui,Long Xu,Dongming Lan,Bo Yang,Yonghua Wang
Our study offers a novel sn -1,3 specific lipase MAJ1 from marine member Janibacter sp. strain HTCC2649 for preparing long-medium-long (LML) type structured triacylglycerols (TAGs). Firstly, the resin ECR1030 was selected as a suitable support for the immobilization of lipase MAJ1. An efficient synthesis of LML-type structured TAGs by the immobilized lipase MAJ1-catalyzed interesterification of methyl palmitate and tricaprylin was studied in a solvent-free system. The reaction conditions, including substrate molar ratio, temperature and enzyme loading, were optimized. Under the optimum conditions (immobilized lipase MAJ1 of 45 U/g, substrate molar ratio of 4:1, temperature of 35 °C, reaction time of 24 h), the structured TAGs with double long chains (DLCST) were obtained in a yield of 44.3 mol%. Secondly, multi-dimensional mass spectrometry-based shotgun lipidomics (MDMS-SL) was employed to quantify each TAG positional isomer in DLCST. The content of 1,3-dipalmitoyl-2-capryloyl- sn -glycerol in DLCST was 97.6% determined by the MDMS-SL technology.
研究领域:
生物化学
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酶工程
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脂质组学
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产品关联
DOI
PubMed
高影响因子
BIORESOURCE TECHNOLOGY
·
2024
·
IF 9.7
Guofu Zhao,Ming Chen,Jingwen Liu,Shang Wang,Dongmei Fu,Chunzhi Zhang
Antioxidant addition is an effective strategy to achieve docosahexaenoic acid (DHA) overproduction in oleaginous microorganisms. Nevertheless, antioxidants like phenolic compounds sometimes exert pro-oxidant activity. In this work, effects of proanthocyanidins (PAs) on fermentation performance and oxidative stress in Schizochytrium sp. were investigated. Low PAs addition (5 mg/L) reduced reactive oxygen species and enhanced lipogenic enzymes activities and NADPH, resulting in significant increase in lipid (20.3 g/L) by 33.6 % and DHA yield (9.8 g/L) by 53.4 %. In contrast, high PAs addition (500 mg/L) exerted pro-oxidant effects, aggravated oxidative damage and lipid peroxidation, leading to sharp decrease in biomass (21.3 g/L) by 35.1 %, lipid (8.2 g/L) by 46.0 %, and DHA (2.9 g/L) by 54.8 %. Therefore, the antioxidant concentration is especially crucial in DHA production. This study is the first to report concentration-dependant dual roles of PAs in oxidative stress and DHA production in Schizochytrium sp., providing new insights into microbial DHA production.
研究领域:
微生物学
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生物化学
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生物技术
✓ 已验证
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2024
·
IF 7.7
Zhongyu Shi,Xiasen Wei,Yunfan Wei,Zheyi Zhang,Sibao Wan,Haiyan Gao,Zhen Qin
A novel glycoside hydrolase (GH) family 16 multi-domain β-1,3-1,4-glucanase (FsGlc16A) from Fibrobacter sp. UWP2 was identified, heterogeneously expressed, and its enzymatic properties, protein structure and application potential were characterized. Enzymological characterization showed that FsGlc16A performed the optimal catalytic activity at pH 4.5 and 50 °C with a specific activity of 3263 U/mg. FsGlc16A exhibited the substrate specificity towards oat β-glucan, barley β-glucan and lichenan, and in addition, it hydrolyzed oat β-glucan and lichenan into different β-glucooligosaccharides with polymerization degrees of 3–4, which further illustrated that it belonged to the endo-type β-1,3-1,4-glucanase. FsGlc16A was classified in subfamily25 of GH16. A ‘PXSSSS’ repeats domain was identified at the C-terminus of FsGlc16A, which was distinct from the typical GH family 16 β-1,3-1,4-glucanases. Removing the ‘PXSSSS’ repeats domain affected the binding of the substrate to FsGlc16A and reduced the enzyme activity. FsGlc16A displayed good potential for the applications, which hydrolyzed oat bran into β-glucooligosaccharides, and reduced filtration time (18.89 %) and viscosity (3.64 %) in the saccharification process. This study investigated the enzymatic properties and domain function of FsGlc16A, providing new ideas and insights into the study of β-1,3-1,4-glucanase.
研究领域:
生物化学
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酶学
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微生物学
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食品科学
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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）