Metabolomics
·
2022
·Vol. 18
·期 11
·1-14
·
IF 4.747
Li Yongyu,Tian Sicheng,Yang Le,Bao Xiaoming,Su Lin,Zhang Xiang,Liu Sijing,Zhu Yalan,Yang Jiaxue,Lin Hua,Zhang Jing,Zeng Jumei,Wang Chuan,Tang Tian
Introduction Previous reports revealed the role played by Salmonella PhoP–PhoQ system in virulence activation, antimicrobial tolerance and intracellular survival, the impact of PhoP–PhoQ on cell metabolism has been less extensively described. Objectives The aim of this study is to address whether and how the PhoP–PhoQ system affects the cell metabolism of Salmonella. Methods We constructed a Salmonella phoP deletion mutant strain TT-81 (PhoP-OFF), a Salmonella PhoP constitutively expressed strain TT-82 (PhoP-ON) and a wild-type Salmonella PhoP strain TT-80 (PhoP-N), using P22-mediated generalized transduction or λ Red-mediated targeted mutagenesis. We then measured the in vitro growth kinetics of all test strains and determined their metabolomic and transcriptomic profiles using gas chromatography coupled with tandem mass spectrometry (GC–MS/MS) and RNA-seq technique, respectively. Results Low-Mg 2+ conditions impaired the growth of the phoP deletion mutant strain TT-81 (PhoP-OFF) dramatically. 42 metabolites in the wild-type PhoP strain TT-80 (PhoP-N) and 28 metabolites in the PhoP constitutively expressed strain TT-82 (PhoP-ON) changed by the absence of phoP . In contrast, the level of 19 compounds in TT-80 (PhoP-N) changed comparing to the PhoP constitutively expressed strain TT-82 (PhoP-N). The mRNA level of 95 genes in TT-80 (PhoP-N) changed when phoP was disrupted, wherein 78 genes downregulated and 17 genes upregulated. 106 genes were determined to be differentially expressed between TT-81 (PhoP-OFF) and TT-82 (PhoP-ON). While only 16 genes were found to differentially expressed between TT-82 (PhoP-ON) and TT-80 (PhoP-N). Conclusion Our findings confirmed the impact of PhoP–PhoQ system on lipopolysaccharide (LPS) modification, energy metabolism, and the biosynthesis or transport of amino acids. Most importantly, we demonstrated that the turnover of a given metabolite could respond differentially to the level of phoP . Taken together, the present study provided new insights into the adaptation of Salmonella to the host environment and helped to characterize the impact of the PhoP–PhoQ system on the cell metabolism.
✓ 已验证
DOI
PubMed
高影响因子
MICROCHIMICA ACTA
·
2019
·Vol. 187
·期 1
·1-10
·
IF 5.479
Lv Man-Man,Fan Shuang-Fei,Wang Qiong-Lin,Lv Qi-Yan,Song Xiaojie,Cui Hui-Fang
An ultrasensitive enzyme-free electrochemical sandwich DNA biosensor is described for the detection of ssDNA oligonucleotides. A DNA sequence derived from the genom of Helicobacter pylori was selected as a model target DNA. The DNA assay was realized through catching target DNA on capture DNA immobilized gold electrode; then labeling the target DNA with reporter DNA (rpDNA) and initiator DNA (iDNA) co-modified gold nanoparticles (AuNPs). The high density of iDNAs serves as one of the amplification strategies. The iDNA triggers hybridization chain reaction (HCR) between two hairpins. This leads to the formation of a long dsDNA concatamer strand and represents one amplification strategy. The electrochemical probe [Ru(NH 3 ) 5 L] 2+ , where L stands for 3-(2-phenanthren-9-ylvinyl)pyridine, intercalated into dsDNA chain. Multiple probe molecules intercalate into one dsDNA chain, serving as one amplification strategy. The electrode was subjected to differential pulse voltammetry for signal acquisition, and the oxidation peak current at −0.28 V was recorded. On each AuNP, 240 iDNA and 25 rpDNA molecules were immobilized. Successful execution of HCR at the DNA-modified AuNPs was confirmed by gel electrophoresis and hydrodynamic diameter measurements. Introduction of HCR significantly enhances the DNA detection signal intensity. The assay has two linear ranges of different slopes, one from 0.01 fM to 0.5 fM; and one from 1 fM to 100 fM. The detection limit is as low as 0.68 aM. Single mismatch DNA can be differentiated from the fully complementary DNA. Conceivably, this highly sensitive and selective assay provides a general method for detection of various kinds of DNA.
Schematic representation of the detection and the amplification principles of the electrochemical sandwich DNA assay. Purple curl: Captured DNA; Green curl: Reporter DNA; Orange curl: HCR initiator DNA; Yellow solid-circle: Gold nanoparticle; H1 and H2: Two hairpin DNA; [Ru(NH 3 ) 5 L] 2+ : Signal probe.
✓ 已验证
DOI
PubMed
高影响因子
MICROCHIMICA ACTA
·
2018
·Vol. 185
·期 5
·1-10
·
IF 5.705
Cheng Wenjie,Pan Jiahong,Yang Jianying,Zheng Zengyao,Lu Fushen,Chen Yaowen,Gao Wenhua
A photoelectrochemical (PEC) aptasensor for the highly sensitive and specific detection of thrombin is described. This aptasensor is based on an indium tin oxide (ITO) support that is covered with carbon quantum dot (CQD)-sensitized TiO 2 and acts as a photoactive matrix. The ITO/TiO 2 /CQD electrode was prepared by impregnation assembly. It displays an enhanced and steady photocurrent response under irradiation by visible light. A carboxyl-functionalized thrombin-binding aptamer was covalently immobilized on the modified ITO to obtain a PEC aptasensor whose photocurrent decreases with increasing concentration of thrombin. Under 420 nm irradiation at a bias voltage of 0 V, the aptasensor has a linear response in the 1.0 to 250 pM thrombin concentration range, with a 0.83 pM detection limit. Conceivably, this approach can be extended to numerous other PEC aptasensors for the detection of targets for which appropriate aptamers are available.
Schematic of a PEC aptasensor for thrombin. It is based on the use of CQD as the sensitizer, TiO 2 /CQDs as the photoactive matrix, and the thrombin aptamer as the recognition element.
✓ 已验证
DOI
PubMed
高影响因子
CHINESE SCIENCE BULLETIN
·
2014
·Vol. 59
·期 10
·964-970
·
IF 1.365
Zhan Lei,Peng Li,Huang Cheng-Zhi
Combining the unique optical properties of metal nanoparticles and the specific recognition of aptamer, aptamer–nanoparticle conjugates have been extensively used in a wide range of applications, particularly multifunctional nanoparticles for cell detection and molecular imaging. Conventional conjugates prepared by chemisorption of monothiol-modified oligonucleotides onto nanoparticle surfaces suffer from a lack of stability when exposed to a variety of small molecules. If silver is used in place of gold, then this lack of stability is even more pronounced. In this study, we reported here the effective and facile strategy of preparing stable silver nanoparticle–aptamer conjugates by in situ generation of strong metal affinity capping ligands, dithiocarbamates modified anti-prion protein aptamer. The conjugates produced are stable and can withstand NaCl concentration at 0.25 mol/L. Meanwhile, they could be applied in the cellular prion protein imaging successfully.
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2019
·Vol. 26
·期 26
·27052-27062
·
IF 2.914
Huang Jingang,Chen Susu,Wu Weihong,Chen Huiping,Guo Kangyin,Tang Junhong,Li Jianping
Anaerobic fermentation of waste activated sludge (WAS) for recycling valuable volatile fatty acids (VFAs) is economically valuable. However, the fermentation of protein is the rate-limiting step of VFA production with WAS as a substrate. In this study, the effect of redox mediators (RMs, i.e., riboflavin and lawsone) on the enhanced production of VFAs from WAS was investigated. The results indicate that both RMs can promote protein-dependent fermentation, increasing maximum VFA accumulation by 43.9% and 42.5% respectively. In cultures supplemented with riboflavin and lawsone, VFA production was highly correlated with protease activities, but not with α-glucosidase activities. This implies that RMs affected the redox reaction of amino acids degradation, resulting in an increased release of ammonia. Sequencing results showed that RMs significantly increased the abundance of bacteria related to VFA fermentation and protein/amino acid degradation at the levels of phylum, class, order, family, and even genus.
✓ 已验证
DOI
PubMed
高影响因子
Scientific Reports
·
2018
·Vol. 8
·期 1
·1-8
·
IF 4.122
Zhang Hong,Li Xintong,He Fan,Zhao Mingqin,Ling Liansheng
A novel turn-off colorimetric sensor for sequence-specific recognition of single-stranded DNA (ssDNA) was established by combining Y-shaped DNA duplex and G-quadruplex-hemin DNAzyme. A G-rich single-stranded DNA (Oligo-1) displays peroxidase mimicking catalytic activity due to the specific binding with hemin in the presence of K + , which was able to catalyze the oxidation of colorless 2,2′-azinobis(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS 2− ) by H 2 O 2 to generate green ABTS− radical for colorimetric assay. Oligonucleotide 2 (Oligo-2) was partly complementary with Oligo-1 and the target DNA. Upon addition of target DNA, Oligo-1, Oligo-2 and target DNA can hybridize with each other to form Y-shaped DNA duplex. The DNAzyme sequence of Oligo-1 was partly caged into Y-shaped DNA duplex, resulting in the inactivation of the DNAzyme and a sharp decrease of the absorbance of the oxidation product of ABTS 2− . Under the optimum condition, the absorbance decreased linearly with the concentration of target DNA over the range of 1.0–250 nM and the detection limit was 0.95 nM (3σ/slope) Moreover, satisfied result was obtained for the discrimination of single-base or two-base mismatched DNA.
✓ 已验证
DOI
PubMed
高影响因子
MICROCHIMICA ACTA
·
2021
·Vol. 188
·期 8
·1-11
·
IF 5.833
Zhang Youxiong,Li Bing,Wei Xianhu,Gu Qihui,Chen Moutong,Zhang Jumei,Mo Shuping,Wang Juan,Xue Liang,Ding Yu,Wu Qingping
A facile and versatile competitive electrochemical aptasensor for tobramycin (TOB) detection is described using electrochemical-deposited AuNPs coordinated with PEI-functionalized Fe-based metal-organic framework (AuNPs/P-MOF) as signal-amplification platform and a DNA probe labeled with methylene blue (MB) at the 3′-end (MB-Probe) as a signal producer. First, F-Probe (short complementary DNA strands of both the aptamer and the MB-Probe label with a sulfhydryl group at the 5′-end) was immobilized on the AuNPs/P-MOF modified electrode as detection probes, which competed with TOB in binding to the aptamer. TOB-aptamer binding resulted in F-Probe remaining unhybridized on the electrode surface, so that a significant current response was generated by hybridizing with MB-Probe instead. The developed strategy showed favorable repeatability, with a relative standard deviation (RSD) of 4.3% computed over five independent assays, and high stability, with only 6.8% degradation after 15 days of storage. Under optimal conditions, the proposed aptamer strategy exhibited a linear detection range from 100 pM to 500 nM with a limit of detection (LOD) of 56 pM (S/ N = 3). The electrochemical aptasensor demonstrated remarkable selectivity, and its feasibility for accurate and quantitative detection of TOB in milk samples was confirmed (RSD < 4.5%). Due to its simple design, easy operation, and high sensitivity and selectivity, the proposed method could expect to detect other antibiotics by replacing the aptamers. In summary, this study provides a simple and effective new strategy for electrochemical aptasening based on MOF-based sensing interface. Graphical abstract
Scheme illustration of label-free competitive electrochemical aptamer-based detection of tobramycin based on electrochemically deposited AuNPs coordinated with PEI-functionalized Fe-based metal-organic framework as signal-amplification platform.
✓ 已验证
DOI
PubMed
高影响因子
Nature Communications
·
2021
·Vol. 12
·期 1
·1-9
·
IF 14.919
Yang Yonggang,Wang Zegao,Gan Cuifen,Klausen Lasse Hyldgaard,Bonné Robin,Kong Guannan,Luo Dizhou,Meert Mathijs,Zhu Chunjie,Sun Guoping,Guo Jun,Ma Yuxin,Bjerg Jesper Tataru,Manca Jean,Xu Meiying,Nielsen Lars Peter,Dong Mingdong
Long-distance extracellular electron transfer has been observed in Gram-negative bacteria and plays roles in both natural and engineering processes. The electron transfer can be mediated by conductive protein appendages (in short unicellular bacteria such as Geobacter species) or by conductive cell envelopes (in filamentous multicellular cable bacteria). Here we show that Lysinibacillus varians GY32, a filamentous unicellular Gram-positive bacterium, is capable of bidirectional extracellular electron transfer. In microbial fuel cells, L. varians can form centimetre-range conductive cellular networks and, when grown on graphite electrodes, the cells can reach a remarkable length of 1.08 mm. Atomic force microscopy and microelectrode analyses suggest that the conductivity is linked to pili-like protein appendages. Our results show that long-distance electron transfer is not limited to Gram-negative bacteria.
✓ 已验证
DOI
PubMed
高影响因子
Nature Communications
·
2021
·Vol. 12
·期 1
·1-16
·
IF 14.919
Wang Yongchao,Gong Ningqiang,Ma Chi,Zhang Yuxuan,Tan Hong,Qing Guangchao,Zhang Jimei,Wang Yufei,Wang Jinjin,Chen Shizhu,Li Xianlei,Ni Qiankun,Yuan Yuan,Gan Yaling,Chen Junge,Li Fangzhou,Zhang Jinchao,Ou Caiwen,Zhao Yongxiang,Liu Xiaoxuan,Liang Xing-Jie
Immunological adjuvants are essential for successful cancer vaccination. However, traditional adjuvants have some limitations, such as lack of controllability and induction of systemic toxicity, which restrict their broad application. Here, we present a light-activable immunological adjuvant (LIA), which is composed of a hypoxia-responsive amphiphilic dendrimer nanoparticle loaded with chlorin e6. Under irradiation with near-infrared light, the LIA not only induces tumour cell lysis and tumour antigen release, but also promotes the structural transformation of 2-nitroimidazole containing dendrimer to 2-aminoimidazole containing dendrimer which can activate dendritic cells via the Toll-like receptor 7-mediated signaling pathway. The LIA efficiently inhibits both primary and abscopal tumour growth and induces strong antigen-specific immune memory effect to prevent tumour metastasis and recurrence in vivo. Furthermore, LIA localizes the immunological adjuvant effect at the tumour site. We demonstrate this light-activable immunological adjuvant offers a safe and potent platform for in situ cancer vaccination.
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF NANOBIOTECHNOLOGY
·
2022
·Vol. 20
·期 1
·1-13
·
IF 9.429
Gu Jun,Zhao Gang,Yu Jiangkun,Xu Pei,Yan Jiabin,Jin Zhengshuai,Chen Sheng,Wang Yong,Zhang Leshuai W.,Wang Yangyun
Although combination chemoimmunotherapy shows promising clinical results for cancer treatment, this approach is largely restricted by variable objective response rate and severe systemic adverse effects of immunotherapeutic antibody and chemotherapeutic drugs. Therefore, an in situ-formed therapeutic silk-chitosan composite scaffold is fabricated in this study to allow local release of the chemotherapeutic drug doxorubicin (DOX) and JQ1 (small molecular inhibitor used for the extraterminal protein BRD4 and bromodomain) with control release kinetics. DOX-JQ1@Gel contains a pH-degradable group that releases therapeutics in a weak acidic tumor microenvironment. The released DOX could directly kill tumor cells or lead to immunogenic cell death, thereby triggering the response of antitumor immunity. Meanwhile, chemotherapy-triggered antigen release and JQ1-mediated PD-L1 checkpoint blockade cumulatively contribute to trigger the response of antitumor immunity. Finally, the DOX-JQ1@Gel is locally injected to evaluate its synergistic cancer therapeutic effect, which is expected to improve objective response rate of immunotherapy and minimize systemic side effects.Graphical Abstract
✓ 已验证
DOI
PubMed
高影响因子
Bioresources and Bioprocessing
·
2022
·Vol. 9
·期 1
·1-11
·
IF 4.983
Liu Yangyang,Sun Qihao,Hao Mengyang,Tan Wen‑Song,Cai Haibo
The application of natural killer (NK) cells as potential antitumor effector cells appears to be valuable for immunotherapies. However, the clinical use of NK cells is limited because the technical difficulties associated with mass production NK cells at sufficiently high numbers represents a great challenge. Ex vivo expansion of NK cells is a key technology for cell therapy. Bioreactor systems can generate homogeneous culture condition and modulate the environmental and biochemical cues. In this study, a novel magnetically controlled bioreactor was developed for supporting NK cells ex vivo expansion. Using synthetic magnetic beads, the stirring device of the magnetically controlled bioreactor generated reduced shearing force. The intermittent magnetic field was applied for magnetic beads movement to homogenize the culture system. NK-92 cells were cultured in the magnetically controlled bioreactor and the expansion and function of expanded cells were investigated on day 8. The results showed that the expansion of NK-92 cells in the bioreactor was 67.71 ± 10.60-fold, which was significantly higher than that of the T25 culture flask (P < 0.05). Moreover, the proportions of CD3−CD56+ cells and cell killing activity of expanded cells in the bioreactor did not reveal any differences compared to T25 flasks. Taken together, this study demonstrated the possibility of magnetically controlled bioreactor as a potent strategy in NK cells production for facilitating cancer immunotherapy.
✓ 已验证
DOI
高影响因子
MICROCHIMICA ACTA
·
2019
·Vol. 186
·期 9
·1-9
·
IF 5.479
Yue Qiaoli,Hu Yingying,Tao Lixia,Zhang Baoqian,Liu Chen,Wang Yongping,Chen Chunying,Zhao Jinsheng,Li Chen-Zhong
A fluorometric method is described for “turn-on” sensing of pH values via black phosphorus quantum dots (BPQD). Water-stable BPQD were synthesized by a liquid exfoliation method and characterized by TEM, FT-IR, XPS, and absorption and fluorescence spectra. The nanoparticles of BPQD have a uniform distribution with an average size of 5.2 nm. They exhibit bright green fluorescence, with excitation/emission maxima at 420/515 nm. The fluorescence of the BPQD is likely to arise from the quasi-molecular fluorophores of polycyclic aromatic compounds carrying P-P, P-O-P, and P x O y functions on its surface. The protonation and deprotonation of hydroxyl groups of BPQD causes a different degree of quenching of the BPQD. At pH values below 4.0, protons bind to BPQD to form non-fluorescent ground state complexes. At pH values above 4.0, the hydroxyl groups become deprotonated, and this induces the recovery of fluorescence. The sensor has a linear response in the pH range of 1.0–9.0. It was successfully applied to the determination of the pH values in human urine and serum samples.
Schematic representation of the preparation of black phosphorus quantum dots (BPQDs) from powdered BP crystals using liquid-phase exfoliation in N-methyl-2-pyrrolidone solution. The BPQDs display green fluorescence at high pH values but no fluorescence at very low pH values.
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）