JOURNAL OF MICROBIOLOGY AND BIOTECHNOLOGY
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2025
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IF 3.1
Kaize Kong,Feitao Chen,Huan Fang,Pingtao Jiang,Xinfang Zhao,Jijiao Zhang,Huina Dong,Hongxing Jin,Dawei Zhang
Isopropyl β-D-thiogalactopyranoside (IPTG), while widely utilized for inducing gene expression in systems governed by T7 lac and related promoters, poses significant challenges due to its toxicity and expense, prompting the exploration of alternative induction strategies. In this study, we developed a series of inducer-free vitamin B 12 -producing strains featuring thermally regulated pathway genes. We engineered a thermal switch by replacing the lacI promoter with the P R promoter, which is regulated by the temperature-sensitive repressor cI857 from the λ bacteriophage. As a result, target genes driven by T7 lac or other lac -derived promoters containing lac operators were expressed upon lowering the temperature. Our findings indicate that culturing at 37°C and then shifting to 32°C when the optical density at 600 nm reaches 2 is the most effective strategy for vitamin B 12 production. Additionally, the vitamin B12 titer increased by 37.96% after introducing an ssrA degradation tag at the C-terminus of lacI . This study introduces a novel strategy for vitamin B 12 production that circumvents the need for IPTG by implementing a thermal switch. This approach may have significant implications for chemical bioproduction processes that have traditionally relied on IPTG for gene induction.
研究领域:
合成生物学
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代谢工程
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分子生物学
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DOI
PubMed
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2017
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IF 2.536
Longhua Ding,Hongmei Yang,Shenguang Ge,Jinghua Yu
A simple and effective fluorescent assay for the determination of vitamin B 12 was developed. In this study, carbon dots (CDs) were prepared by one-pot hydrothermal method and directly used as a fluorophore in the inner filter effect (IFE). Both of the maximum absorption peak of vitamin B 12 and excitation maxima of CDs are located at 360 nm, hence, the excited light of CDs can be absorbed by vitamin B 12 , resulting in the fluorescence reduction of CDs. And the fluorescence intensity of CDs decreases with the increasing concentration of vitamin B 12 . This IFE-based sensing strategy shows a good linear relationship between the normalized fluorescence intensity and the concentration of vitamin B 12 ranging from 0 to 60 μM, with a limit of detection (LOD) of 0.1 μM at a signal-to-noise ratio of 3. Furthermore, this proposed approach was successfully applied to vitamin B 12 sensing in injections. This IFE sensing platform based on various fluorescent nanomaterials has a high promise for the detection of other biomolecules due to its inherent convenience.
研究领域:
分析化学
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生物医学
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DOI
PubMed
高影响因子
LUMINESCENCE
·
2019
·Vol. 34
·期 6
·544-552
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IF 1.691
Yao Long,Li Zhang,Ying Yu,Bixia Lin,Yujuan Cao,Manli Guo
A simple and rapid detection strategy for vitamin B 12 (VB 12 ) was established based on label-free silicon quantum dots (SiQDs); the detection mechanism was additionally investigated. SiQDs were synthesized using a one-step microwave method, and their fluorescence was stronger than that synthesized using the hydrothermal method. SiQDs fluorescence was quenched using VB 12 due to the inner filter effect (IFE), which was demonstrated using ultraviolet (UV) absorption spectra, fluorescence lifetime, transmission electron microscopy and zeta potential analysis. Subsequently, quercetin (Que) and doxorubicin (Dox) with absorption peaks that overlapped the excitation or emission peaks of SiQDs respectively were used as control groups to investigate the quenching mechanism. Results showed that quenching efficiency was related to the level of overlap between the adsorption peak of the quencher and the excitation or emission peaks of SiQDs. A greater level of overlap caused a higher quenching efficiency. Therefore, the sensitive quenching of VB 12 for SiQDs was due to the synergistic effect of the synchronous overlap between the absorption peak of VB 12 with the excitation and emission peaks of SiQDs. Fluorescence quenching efficiency increased linearly in the 0.5 to 16.0 μmol·L −1 VB 12 concentration range, and the detection limit was 158 nmol·L −1 . In addition, SiQDs were applied to determine VB 12 in tablets and human urine samples with satisfactory recoveries ranging from 97.7 to 101.1%.
研究领域:
分析化学
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生物医学
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DOI
PubMed
高影响因子
JOURNAL OF AOAC INTERNATIONAL
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2022
·Vol. 105
·期 5
·1350-1359
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IF 2.028
Xiang Yingying,Song Fei,Jiang Lei,Liu Ze,Tu Yujiao
BackgroundVB12 is involved in the production of bone marrow red blood cells, preventing pernicious anemia and brain nerve damage.ObjectiveA large edible fungus Lactarius hatsudake (Lh) was used as a carbon source to produce fluorescent carbon dots (CDs) with high quantum yield and high photostability by a one-step hydrothermal method.MethodThe structure and optical properties of Lh-CDs were characterized by XRD, XPS, FTIR, and UV-Vis, and the stability of Lh-CDs was studied. The maximum excitation wavelength and emission wavelength of Lh-CDs were 324 and 408 nm, respectively, and the average fluorescence lifetime was 2.29 ns.ResultsThe linear range is 0∼20 μM (R2 = 0.9972) with a detection limit of 36.9 nM. At the same time, the mechanism of fluorescence quenching was internal filtration effect.ConclusionsIt showed that Lh-CDS had good selectivity, high sensitivity, and good anti-interference ability to VB12, which provided a new detection method for VB12.Highlights The fluorescence intensity of the LH-CDs could be effectively quenched by VB12.HighlightsThe fluorescence intensity of the LH-CDs could be effectively quenched by VB12.
研究领域:
生物化学
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分析化学
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DOI
PubMed
高影响因子
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
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2022
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IF 4.831
Xiaosong Huang,Zhikun Liu,Yiqian Huang,Yi Zong,Xiaoyi Yang,Zhengqiang Hu,Cheng Zeng
Fluorescent carbon dots (CDs) with the long-wavelength emission have received increasing attention due to their promising application prospects in the biological field. The synthesis of CDs with long wavelength emission mainly focuses on the high temperature method, but the room temperature synthesis is still rarely studied. Herein, a simple room temperature strategy is developed for the preparation of orange-emitting CDs (O-CDs) by Schiff base crosslinking reaction between methyl- p -benzoquinone and triethylenetetramine. The proposed O-CDs show a strong excitation-dependent emission with a relative quantum yield of about 6.56%. Because of the strong inner filter effect, O-CDs can be well applied for the highly-sensitive detection of vitamin B12 (VB12). The intensity ratio ( F / F 0 ) of O-CDs is linear against the concentration of VB12 from 50 nM to 200 μM with a low detection limit of 10 nM. Therefore, the obtained O-CDs nanoprobes provide a promising platform for pharmaceutical analysis applications.
研究领域:
生物医学
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材料科学
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分析化学
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DOI
PubMed
高影响因子
MICROCHEMICAL JOURNAL
·
2024
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IF 4.9
Shen Zhang,Xiao Wang,Yutong Wang,Jiaxu Dong,Yixuan Zhang,Manlin Zhao
Vitamin B12 is a drug that can participate in the production of bone marrow red blood cells, prevention of pernicious anemia and damage to brain nerves. It is needful to prepare new vitamin B12 determination strategies with excellent sensitivity, selectivity and uniqueness. Herein, a novel and facile chemical reduction method was successfully carried out (histidine and ascorbic acid were applied as protectant and reductant) for preparing histidine-functionalized silver nanoclusters (Ag NCs@his) with blue fluorescence. Some technologies were adopted to clarify the structure, optical characteristics of this stable Ag NCs@his and fluorescence quenching mechanism. Based on inner filter effect, a sensitive and selective platform for vitamin B12 detection was established. Under optimum pH value, reaction time and temperature, the as-developed platform could be utilized to the trace measurement of vitamin B12 with linear range of 0.5–200 μM and detection limit of 0.038 μM. Moreover, this platform was successfully used to measure vitamin B12 in real samples and temperature.
研究领域:
生物化学
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分析化学
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医学检测
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DOI
高影响因子
Journal of Environmental Chemical Engineering
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2023
·
IF 7.7
Xiaoyan Ma,Sinong Huang,Yuhong Jin,Hang Jiang,Liangjie Tang,Yifei Wu,Yongjiong Ni,Shijun Zhu,Xueyan Li,Andrea M. Dietrich
Haloacetic acids (HAAs) are ubiquitously detected in drinking water and even persistent after boiling due to their stability and nonvolatility, which leads to risk exposure to human. To minimize the risk, HAAs removal through electrocatalytic reduction easily utilized in point-of-use household devices is proposed. Trichloroacetic acid (TCAA) as a typical target, was investigated using laboratory-prepared metal electrode modified with Vitamin B12 (VB12) by the drop coating method. The dechlorination performance and effects of influencing factors on the TCAA dechlorination by VB12/metal composite cathode were studied. Under the conditions of 10.0 mg VB12 loading and 7.0 mA/cm 2 current density, 92.9% TCAA removal efficiency was achieved within 5 h at 25 °C in neutral water solution. The degradation processes followed the first-order kinetic model. The results show that VB12/iron (Fe) electrode presented the superior electrocatalytic activity than VB12/aluminium and VB12/copper. The dechlorination efficiency of TCAA was promoted by higher VB12 loadings and current density; inhibited by alkaline condition and higher initial concentration of TCAA. The synergistic effect between atomic H* and VB12 occurred during the TCAA dechlorination process through the electron transfer . The proposed pathway elucidated that TCAA was dechlorinated to form dichloroacetic acid (DCAA) and monochloroacetic acid (MCAA), with acetic acid and chloride as ultimate products. This electrocatalysis system with VB12/Fe composite electrode exhibits high reaction efficiency, targeted dehalogenation, and environmental friendliness. This work is expected to provides a new way for the removal of halogenated DBPs at the tap and the safeguard drinking water for consumers.
研究领域:
环境科学
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化学工程
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水处理技术
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Zhuyu Sun,Dan Geng,Chaojie Zhang,Jiabin Chen,Xuefei Zhou,Yalei Zhang,Qi Zhou,Michael R. Hoffmann
Due to the extremely high stability of perfluorooctane sulfonate (PFOS), effective defluorination is difficult. Previous studies indicated that PFOS can be decomposed under the catalysis of vitamin B12 (VB12) with strong artificial reductants such as Ti(III)-citrate and nZn 0 . In this study, we explored if naturally occurring reductant like sulfide (S 2− ) could initiate the reaction. In S 2− /VB12 system, branched PFOS (br-PFOS) can undergo effective decomposition and defluorination at the temperature of 70 °C and pH greater than 12. The degradation of br-PFOS fits pseudo-first-order kinetic with a rate constant of 0.0984 ± 0.0034 d -1 in the presence of 30 mM Na 2 S and 300 μM VB12, while linear PFOS (L-PFOS) remained stable during 30 d reaction process. UV–Vis spectral characterization indicates that S 2− reduces VB12(Co III ) to Co II , which is able to initiate the reductive defluorination. Based on the product analysis, HF/2F elimination followed by C–C scission is the dominant degradation pathway of br-PFOS instead of stepwise H/F exchange. The primary products include F − and polyfluorinated sulfonates and carboxylates. The degradation of br-PFOS is strongly dependent on temperature due to a relatively high apparent activation energy of 62.86 kJ/mol. Strong alkaline condition can greatly enhance the decomposition efficiency since S 2− is the primary reactive form. This study provides new insights into the VB12-catalyzed defluorination of PFOS and a feasible approach for future natural or engineered remediations of br-PFOS.
研究领域:
环境科学
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化学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2017
·
IF 6.216
Bo Yang,Jianping Deng,Liyan Wei,Yanni Han,Gang Yu,Shubo Deng,Caizhen Zhu,Huabo Duan,Qiongfang Zhuo
2,2′,4,4′-Tetrabromodiphenyl ether (BDE47) is known as a recalcitrant bromated organic pollutant with the significant persistence, toxicity, and bioaccumulation. In this study, a synergistic effect of ball-milled Al particles with vitamin B 12 on the degradation of BDE47 was found according to the coordinated catalytic reduction process. The micro-scale Al particles prepared by ball milling and vitamin B 12 as common pharmaceutical composed a new combination reagent for hydrodebromination with low-cost and high reactivity. The degradation conditions were optimized by the addition of 2.0 g/L BM Al particles and 0.3 mM VB 12 using the solvent of methanol/H 2 O (v:v = 40:60) at pH 4.0. More than 97% of 25 mg/L BDE47 was debrominated into lower-brominated diphenyl ethers in a sequential pattern and finally into diphenyl ethers within a 120-min reaction. UV/Visible spectra showed that vitamin B 12 (Co(III)) was reduced to vitamin B 12s (Co(II)) by the ball-milled Al particles, which possesses super nucleophilic property to associate the carbon atom on C Br bond and then facilitates the hydrodebromination process of brominated diphenyl ethers. The experimental results can provide basic understanding to identify a reaction process of vitamin B 12 /vitamin B 12s for the enhanced reductive debromination of polybrominated diphenyl ethers by ball-milled Al particles, which would be possibly applied to treat soil washing solvent in the field of soil remediation.
研究领域:
环境科学
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化学
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产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2025
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IF 5.4
Xiaoyan Ma,Kunming Wei,Hongwei Liu,Qi Zheng,Wenqing Cao,Liang Zhang,Liangjie Tang,Stefanos Giannakis,Jing Deng,Su Jiang,Daniel L. Gallagher,Andrea M. Dietrich
Haloacetic acids (HAAs) are prevalently occurred in drinking water after disinfection by chlorine or chloramine, classified as the non-volatile and thermally stable disinfection byproducts (DBPs). To minimize the existed HAAs, catalytical electrolysis based on effective cathode was employed. Dehalogenation of HAAs were improved by vitamin B12 (VB12) coating on the stainless steel (SS), iron, copper, and aluminum electrodes. The VB12/SS composite electrode proved to be the optimal for the synergistic effect of VB12 and metal substrate on the DCAA degradation. Target chloro-, bromo-, and iodo-HAAs were catalytically decomposed, and their dehalogenation efficiency and mechanistic pathway were compared. The results show that HAAs electrolytic dehalogenation rates were significantly related with both the degree of halogenation (tri > di > mono) and the halogen atomic weight (I > Br > Cl). Dehalogenation of HAAs follows a first-order kinetic model, and kinetic variations were well described by a linear model. The logarithm base 10 of the dehalogenation rate constant k was proportional to its HAA molecular weight: log 10 (k) =0.00237 MW -0.85. The intermediate dehalogenation products were identified as less-halogenated acetic acids, and the final were acetic acid and halide ions. No mineralization occurred according to carbon conservation analysis. ESR detection and quenching experiments confirmed that HAAs dehalogenation was mainly an indirect reduction mediated by atomic H*. The synergistic effect between atomic H* and VB12 occurred through the electron transfer. This comparative study of various HAAs dehalogenation provides a mechanism of dehalogenation and a predictive linear model for electrolysis of HAAs.
研究领域:
环境科学
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化学工程
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DOI
高影响因子
ACS Applied Materials & Interfaces
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2023
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IF 9.5
Qing Li,Xinke Yu,Shiqi Zhang,Mengyue Xu,Yunyi Yang,Zhili Wan,Xiaoquan Yang
Supramolecular hydrogels self-assembled from naturally occurring small molecules (e.g., glycyrrhizic acid, GA) are promising materials for controlled bioactive delivery due to their facile fabrication processes, excellent biocompatibility, and versatile stimuli-responsive behaviors. However, most of these natural hydrogels suffer from poor mechanical strength and processability for practical applications. In this work, through adopting a multicomponent gel approach, we developed a novel mechanically robust GA-based hydrogel with an interpenetrating double network (DN) that is composed of a Ca2+-enhanced hydrogen-bond supramolecular GA nanofibril (GN) network and a Ca2+cross-linked natural polysaccharide sodium alginate (ALG) network. Compared to the single GN network (SN) hydrogel, the GN-ALG hybrid hydrogels (GN-ALG-DN) with the hierarchical double-network structure possess excellent mechanical properties and shaping adaptation, encouraging small and large amplitude oscillatory shear (SAOS and LAOS) rheological performances, better thermal stability, higher resistance to large compression deformations, and lower swelling behaviors. Furthermore, the GN-ALG-DN hydrogels exhibit a pH-responsive and sustained release behavior of nutrients (i.e., vitamin B12, VB12), showing a faster VB12 release rate with a higher swelling ratio in an alkaline condition (pH 7.5) than in an acidic condition (pH 2.5). This is ascribed to the fact that the higher dissociation degree of carboxylic groups in GA and ALG molecules in an alkaline environment induces the erosion and looseness of the self-assembled GN network and the ionic-cross-linked ALG network, which can lead to the decomposition of the hybrid hydrogels and thereby increases the release of nutrients. Cytotoxicity tests further demonstrate the excellent biocompatibility of the GN-ALG-DN hydrogels. This study highlights the design of robust shaped and structured supramolecular hydrogels from natural herb small molecules, which can serve as solid, edible, and stimuli-responsive active cargo delivery platforms for food, biomedical, and sustainable applications.
研究领域:
材料科学
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生物医学工程
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食品科学
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产品关联
DOI
PubMed
高影响因子
Analytical Methods
·
2021
·Vol. 13
·期 41
·4920-4925
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IF 2.896
Dingyan Fan,Yingzhou Zhang,Haiping Wu
To prevent infants from vitamin B12 deficiency, infant food is designed based on cow's milk or cereal with the fortification of vitamin B12. A method for quantitative determination of vitamin B12 in infant food was developed with hydrophilic high performance liquid chromatography (HPLC) coupled with a diode array detector (DAD). The sensitivity of the detector was enhanced by implementing a 60 mm high-sensitivity LightPipe flow cell, and the limit of detection (LOD) and limit of quantification (LOQ) were improved as low as 0.006 μg 100 g−1 and 0.02 μg 100 g−1 respectively. The effect of sample extraction and enrichment, chromatography separation parameters on the analyte, were studied in detail and optimized. Under these conditions, the method performed a good linear analytical range of 0.3–50 μg L−1, and a good repeatability with % RSD below 2.8% and recovery of 90.2–96.5% (n = 6). To the best of our knowledge, for the first time, 60 mm high-sensitivity LightPipe flow cell was included in the HPLC-DAD method for determination of the trace amount of vitamin B12 in infant food. The proposed method was further validated by analysis of FAPAS QC samples (T21120 and T21118), and it was specific and precise for the intended use.
研究领域:
营养学
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分析化学
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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）