Frontiers in Microbiology
·
2021
·
IF 5.64
Zhao Shuxue,Chen Xi,Sun Qianshu,Wang Fei,Hu Chunhui,Guo Lizhong,Bai Jie,Yu Hao
Indole-3-acetic acid (IAA), known as a common plant hormone, is one of the most distributed indole derivatives in the environment, but the degradation mechanism and cellular response network to IAA degradation are still not very clear. The objective of this study was to elucidate the molecular mechanisms of IAA degradation at the protein level by a newly isolated strain Pseudomonas sp. LY1. Label-free quantitative proteomic analysis of strain LY1 cultivated with IAA or citrate/NH4Cl was applied. A total of 2,604 proteins were identified, and 227 proteins have differential abundances in the presence of IAA, including 97 highly abundant proteins and 130 less abundant proteins. Based on the proteomic analysis an IAA degrading (iad) gene cluster in strain LY1 containing IAA transformation genes (organized as iadHABICDEFG), genes of the β-ketoadipate pathway for catechol and protocatechuate degradation (catBCA and pcaABCDEF) were identified. The iadA, iadB, and iadE-disrupted mutants lost the ability to grow on IAA, which confirmed the role of the iad cluster in IAA degradation. Degradation intermediates were analyzed by HPLC, LC-MS, and GC-MS analysis. Proteomic analysis and identified products suggested that multiple degradation pathways existed in strain LY1. IAA was initially transformed to dioxindole-3-acetic acid, which was further transformed to isatin. Isatin was then transformed to isatinic acid or catechol. An in-depth data analysis suggested oxidative stress in strain LY1 during IAA degradation, and the abundance of a series of proteins was upregulated to respond to the stress, including reaction oxygen species (ROS) scavenging, protein repair, fatty acid synthesis, RNA protection, signal transduction, chemotaxis, and several membrane transporters. The findings firstly explained the adaptation mechanism of bacteria to IAA degradation.
研究领域:
微生物学
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植物学
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环境科学
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DOI
PubMed
高影响因子
EXTREMOPHILES
·
2018
·Vol. 22
·期 3
·473-484
·
IF 2
Chen Kun,Mo Qingshan,Liu Huan,Yuan Feiyan,Chai Haonan,Lu Fuping,Zhang Huitu
A psychrophilic extracellular protease was isolated from the marine bacterium Planococcus sp. M7 found in the deep-sea mud of the Southern Indian Ocean. The mature protease is about 43 kDa and contains 389 amino acids. Sequence alignment revealed that the protease whose catalytic triad was comprised of Ser224, Lys249, and Gln253 contains a catalytic module belonging to the serralysin-type protease family 41, and displays 46.55% identity with the experimentally verified serine protease from Bacillus subtilis str. 168. The enzyme displayed an alkaline mesophilic preference with an optimum pH of 10.0 and an optimum temperature of 35 °C. The enzyme retained its activity from 5 to 35 °C and was resistant to repeated freezing and thawing, but was completely inactivated at 55 °C. Calcium ions had a protective effect against thermal denaturation. More than 60% of the maximum activity was retained at pH values in the range of 5.0–11.0. Almost no activity loss was detected after 1 h of incubation at pH 8.0–10.0 and 20 °C, or with 1.0% SDS. Most important, this protease also showed good stability and compatibility with the standard enzyme-free detergent, which indicates its special interest for applications in detergent industry.
研究领域:
微生物学
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生物化学
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酶学
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海洋生物学
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产品关联
DOI
PubMed
高影响因子
Environmental Technology & Innovation
·
2023
·
IF 7.1
Xingjie Li,Zhigang Zhao,Qiusheng Xiao,Ning He,Jiejie Kong,Daofeng Zhang,Rungen Li,Qin Shao
In this study, the adsorption capacity and mechanism of Cd 2 + by both live and dead Curtobacterium sp. GX_31 biomasses were evaluated using a batch experiment, adsorption isotherm and kinetic models, scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) analysis. The optimal pH, dosage, and contact time were 6.0, 1.0 g/L, and 60 min, respectively. Under optimal conditions, the removal efficiency was >90% for the live biomass and close to 100% for the dead biomass at an initial Cd 2 + concentration of ≤ 10 mg/L, and the maximum adsorption capacities were 37.04 and 40.16 mg/g for the live and dead biosorbents with 200 mg/L Cd 2 + . The R 2 values of the isotherm models indicated that the Temkin isotherm model was best fitted for both the live and dead biomass. The parameters K L (0.3998 vs. 5.1066), n (4.0177 vs. 6.0205), and b T (507.7947 vs. 675.3512) implied that the dead cells had a higher affinity, stronger adsorption, and higher binding energy than the live cells. The kinetic study showed that the pseudo-second-order model was more suitable for depicting the biosorption process, demonstrating that the rate-limiting step might be chemisorption and more than one step, which was confirmed by the intra-particle diffusion model. SEM analysis identified Cd 2 + adsorbed onto the cell surface. FT-IR spectra suggested that hydroxyl, amino, carboxyl, sulphate and carbonyl functional groups might be involved in Cd 2 + adsorption. Based on the results obtained, Curtobacterium sp. GX_31 might be a promising novel biosorbent for Cd 2 + -contaminated soil or water, especially at lower concentrations.
研究领域:
环境生物学
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微生物学
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产品关联
DOI
高影响因子
BIORESOURCE TECHNOLOGY
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2016
·
IF 4.917
Zhiyi Sun,Yongkang Lv,Yuxiang Liu,Ruipeng Ren
A novel heterotrophic nitrifying and metal resistant bacterium was isolated and identified as Cupriavidus sp. S1. The utilization of ammonium, nitrate and nitrite as well as the production of N 2 proved the heterotrophic nitrification and aerobic denitrification ability of S1. The ammonium, nitrate and nitrite removal efficiencies were 99.68%, 98.03% and 99.81%, with removal rates of 10.43, 8.64 and 8.36 mg/L/h, respectively. A multiple regression equation well described the relationship between carbon source utilization, cell growth and nitrification. Keeping the shaking speed at 120 rpm was beneficial for denitrification. Moreover, different forms of nitrogen source could be utilize in simultaneous nitrification and denitrification. Additionally, the efficient removal of ammonium occurred at 20.0 mg/L Zn 2+ , or 10.0 mg/L Ni 2+ or 8.0 mg/L Cu 2+ or 5.0 mg/L Cr 6+ , 33.35 mmol/L sodium pyruvate, C/N 12–28. These findings demonstrate that S1 was effective for nitrogen removal in industrial wastewater containing heavy metal.
研究领域:
微生物学
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环境科学
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废水处理技术
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DOI
PubMed
高影响因子
JOURNAL OF THE AMERICAN COLLEGE OF NUTRITION
·
2017
·
IF 2.107
Jinhui Yu,Yong Ma,Jie Sun,Liyuan Ran,Youwei Li,Ning Wang,Tao Yu,Wenting Gao,Wenbin Jia,Rujiao Jiang,Meihua Guo,Yuping Bi,Yingjie Wu
Objective: Dietary n-3 polyunsaturated fatty acids (PUFAs), especially eicosapentaenoic acids (EPA) and docosahexaenoic acid (DHA), are proved to be effective in obesity reduction. Microalgal oil (MO) is an important alternative source of n-3 PUFAs that effectively alleviates obesity. The aim of the present study was to explore the anti-obesity effects of microalgal oil from Schizochytrium sp. (SMO) and to compare the effects of 2 SMOs (SMO1 and SMO2) with different levels of purity of n-3 PUFAs on high fat diet (HFD)-induced obesity in male C57BL/6J mice.Methods: Mice were randomly divided into 5 groups: (1) regular chow (RC); (2) HFD; (3) HFD + fish oil (FO); (4) HFD + SMO1; and (5) HFD + SMO2. Body weight and food intake were weekly monitored. After 16 weeks of treatment, a glucose tolerance test (GTT) and an insulin tolerance test (ITT) were performed. Serum lipid profile, morphological changes in the liver and epididymal white adipose tissue (eWAT), and the mRNA expression of lipid metabolism–related genes were also examined.Results: SMO treatment significantly decreased HFD-induced abdominal fat accumulation, lowered the levels of triglycerides, cholesterol, and low-density lipoprotein, as did the positive control treated with FO. Morphological examination revealed a remarkable reduction in lipid droplet formation in the liver tissue and the particle size of eWAT. An alleviation of inflammation infiltration in eWAT caused by a high-fat diet was also observed. Real-time reverse transcription–polymerase chain reaction analysis examination confirmed that microalgal oil inhibited the gene expression of fatty acid synthase, sterol responsive element-binding protein-1c, and acetyl-CoA carboxylase but promoted that of hormone-sensitive lipase and lipoprotein lipase, carnitine palmitoyltransferase-1, and uncoupling proteins in the liver and eWAT. Moreover, similar anti-obesity effects were obtained with the same dosage but different purity of n-3 PUFAs.Conclusions: As an alternative n-3 PUFAs resource, dietary intake of SMO might be beneficial to prevent HFD-induced abdominal fat accumulation.
研究领域:
营养学
·
肥胖研究
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分子生物学
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脂质代谢
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2020
·
IF 4.192
Xiaofeng Zhang,Xinqi Xu,Xuemei Yao,Rong Wang,Hengtao Tang,Xin Ju,Liangzhi Li
Ribose-5-phosphate isomerase B is of great importance for biocatalysis and biosynthesis, but the multifunctional residues in active sites hinder the research efforts. This study employed rational design strategies to locate the key residues of RpiB from Ochrobactrum sp. CSL1 (OsRpiB). A single-mutant S9T of a noncontact residue showed 80% activity improvement toward d-allose. A double-mutant S98H/S134H further increased the activity to 3.6-fold. The mutations were analyzed by kinetics and molecular dynamics analyses, indicating that S9T might enhance the substrate binding and catalysis by inducing a steric effect, and S98H/S134H could strengthen both ring opening and binding of d-allose. Though S98H/S134H showed low temperature stability, its potential was explored by isomerizing d-allose to d-psicose with higher conversion and in less reaction time. The findings of this study were beneficial for illustrating the complex functions of key residues in RpiBs and applying OsRpiB in preparing rare sugars.
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
Frontiers in Bioengineering and Biotechnology
·
2021
·
IF 5.89
Yang Ruigang,Zhu Lingyun,Li Tao,Zhu Lv-yun,Ye Zi,Zhang Dongyi
Metabolic engineering of cyanobacteria has received much attention as a sustainable strategy to convert CO2 to various longer carbon chain fuels. Pinene has become increasingly attractive since pinene dimers contain high volumetric energy and have been proposed to act as potential aircraft fuels. However, cyanobacteria cannot directly convert geranyl pyrophosphate into pinene due to the lack of endogenous pinene synthase. Herein, we integrated the gene encoding Abies grandis pinene synthase into the model cyanobacterium Synechococcus sp. PCC 7002 through homologous recombination. The genetically modified cyanobacteria achieved a pinene titer of 1.525 ± 0.l45 mg L−1 in the lab-scale tube photobioreactor with CO2 aeration. Specifically, the results showed a mixture of α- and β-pinene (∼33:67 ratio). The ratio of β-pinene in the product was significantly increased compared with that previously reported in the engineered Escherichia coli. Furthermore, we investigated the photoautotrophic growth performances of Synechococcus overlaid with different concentrations of dodecane. The work demonstrates that the engineered Synechococcus is a suitable potential platform for β-pinene production.
研究领域:
生物技术
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环境科学
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生物化学
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DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2023
·
IF 13.6
Shu-Ting Zhang,Tao Li,Shi-Kai Deng,Jim C. Spain,Ning-Yi Zhou
Nitroanisoles are used widely as synthetic intermediates and explosives. Although bacteria have been reported to degrade 4-nitroanisole (4NA) under aerobic conditions , the key enzymes and the catalytic mechanism have remained elusive. Rhodococcus sp. strain JS3073 was isolated for its ability to grow on 4NA as the sole carbon and energy source. In this study, whole cell biotransformation experiments indicated that 4NA degradation is initiated by O -demethylation to form 4-nitrophenol (PNP), which undergoes subsequent degradation by a previously established pathway involving formation of 1,2,4-benzenetriol and release of nitrite. Based on comparative transcriptomics and heterologous expression, a novel three-component cytochrome P450 system encoded by pnaABC initiates the O -demethylation of 4NA to yield formaldehyde and PNP. The pnaABC genes encode a phthalate dioxygenase type reductase (PnaA), a cytochrome P450 monooxygenase (PnaB), and an EthD family protein (PnaC) with putative function similar to ferredoxins. This unusual P450 system also has a broad substrate specificity for nitroanisole derivatives. Sequence analysis of PnaAB revealed high identity with multiple self-sufficient P450s of the CYP116B subfamily. The findings revealed the molecular basis of the catabolic pathway for 4NA initiated by an unusual O -demethylase PnaABC and extends the understanding of the diversity among P450s and their electron transport chains.
研究领域:
微生物学
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环境科学
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分子生物学
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DOI
PubMed
高影响因子
ENVIRONMENTAL RESEARCH
·
2023
·
IF 8.3
Yuqing Liu,Huiqing Ma,Ang Li,Haixia Pan,Xianliang Yi,Yang Liu,Jingjing Zhan,Hao Zhou
Tellurium (Te) is a rare element within the chalcogen group, and its biogeochemical cycle has been studied extensively. Tellurite (Te(IV)) is the most soluble Te species and is highly toxic to organisms. Chemical or biological Te(IV) reduction to elemental tellurium (Te 0 ) is generally considered an effective detoxification route for Te(IV)-containing wastewater. This study unveils a previously unnoticed Te 0 oxidation process mediated by the manganese-oxidizing bacterium Bacillus sp. FF-1. This bacterium, which exhibits both Mn(II)-oxidizing and Te(IV)-reducing abilities, can produce manganese oxides (BioMnO x ) and Te 0 (BioTe 0 ) when exposed to Mn(II) and Te(IV), respectively. When 5 mM Mn(II) was added after incubating 0.1 mM or 1 mM Te(IV) with strain FF-1 for 16 h, BioTe 0 was certainly re-oxidized to Te(IV) by BioMnOx. Chemogenic and exogenous biogenic Te 0 can also be oxidized by BioMnOx, although at different rates. This study highlights a new transformation process of tellurium species mediated by manganese-oxidizing bacteria, revealing that the environmental fate and ecological risks of Te 0 need to be re-evaluated.
研究领域:
微生物学
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环境科学
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产品关联
DOI
PubMed
高影响因子
WORLD JOURNAL OF MICROBIOLOGY & BIOTECHNOLOGY
·
2021
·Vol. 37
·期 12
·1-12
·
IF 3.312
Zhao Zhenzhen,Liu Chao,Xu Qianqian,Ahmad Shahbaz,Zhang Haiyang,Pang Yu,Aikemu Abudumukeyiti,Liu Yang,Yan Hai
A promising bacterial strain for biodegrading dibutyl phthalate (DBP) was successfully isolated from activated sludge and characterized as a potential novel Microbacterium sp. USTB-Y based on 16S rRNA sequence analysis and whole genome average nucleotide identity (ANI). Initial DBP of 50 mg/L could be completely biodegraded by USTB-Y both in mineral salt medium and in DBP artificially contaminated soil within 12 h at the optimal culture conditions of pH 7.5 and 30 ℃, which indicates that USTB-Y has a strong ability in DBP biodegradation. Phthalic acid (PA) was identified as the end-product of DBP biodegraded by USTB-Y using GC/MS. The draft genome of USTB-Y was sequenced by Illumina NovaSeq and 29 and 188 genes encoding for putative esterase/carboxylesterase and hydrolase/alpha/beta hydrolase were annotated based on NR (non redundant protein sequence database) analysis, respectively. Gene3781 and gene3780 from strain USTB-Y showed 100% identity with dpeH and mpeH from Microbacterium sp. PAE-1. But no phthalate catabolic gene ( pht ) cluster was found in the genome of strain USTB-Y. The results in the present study are valuable for obtaining a more holistic understanding on diverse genetic mechanisms of PAEs biodegrading Microbacterium sp. strains.
研究领域:
环境微生物学
·
基因组学
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DOI
PubMed
高影响因子
ENZYME AND MICROBIAL TECHNOLOGY
·
2019
·
IF 3.553
Li-Quan Ren,Tian-Tian Chang,Da-Peng Ren,Ying Zhou,Bang-Ce Ye
Acinetobacter sp. strain LMB-5 can produce a kind of esterase degrading phthalate esters. However, low activity of Est3563 esterase limited its large-scale application. In this study, computer-aided simulation mutagenesis was used to improve the esterase activity with a tightened screening library and enlarged success rate. Two positive mutants, P218R and A242R, were obtained with 2.5 and 2.1 folds higher than the WT Est3563 esterase, with 11.96 ± 0.45 U·mg −1 and 9.90 ± 0.52 U·mg −1 , respectively. With the help of bioinformatics analysis and three-dimensional printing technology, it was found that the mutations could increase the 240–280 residues swing distance and make them deviate from the catalytic pocket. The instability and deviation of these residues on the lid-like structure of the esterase could deteriorate the seal of the binding pocket and expose the active site. Thus, the catalytic efficiency of the mutants became higher. This result demonstrates that the instability and deviation of the lid-like structure could expand the binding pocket of the esterase and enhance the esterase activity.
研究领域:
酶学
·
生物化学
·
生物技术
·
计算生物学
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DOI
PubMed
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2024
·
IF 5.8
Liqiang Zhang,Ningmin Zhu,Chaochao Wang,Rongzheng Cui,Riyi Lin
Two-step catalytic pyrolysis of Nannochloropsis sp (NS) was conducted with SBA-15 and ZSM-5. Thermogravimetric analyzer (TG) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) were used to investigate the effects of SBA-15 and ZSM-5 on the two-step pyrolysis of NS. The comparative study showed that ZSM-5 and SBA-15 had different effects on the pyrolysis characteristic of NS because of their different property. ZSM-5 had no effects on the kinetic mechanism, but SBA-15 obviously changed DTG curves and the reaction order of the low temperature pyrolysis stage. SBA-15 increased the contents of amines and alkanes to 19.40% and 5.62% in the first step compared with those of the one-step pyrolysis (1.95% and 1.83%). Due to the stronger acid sites, ZSM-5 improved the content of olefins (33.79%) and esters (10.79%) in the first step and the contents of nitriles (11.75%) and aromatic hydrocarbons (31.01%) in the second step compared with those of one-step pyrolysis (10.61%, 5.41%, 0.00%, 8.42%). Acid catalyst had no positive effects on the generation of N-heterocyclic compounds. This study is expected to provide a reference for the efficient pyrolysis utilization of microalgae.
研究领域:
生物能源
·
催化化学
·
环境科学
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DOI
高影响因子
危险品化学品经营许可证（带存储）