Publications by authors named "Xiaoyi Ma"

36 Publications

Rapid detection of using a DNAzyme-based sensor.

Food Sci Nutr 2021 Jul 11;9(7):3873-3884. Epub 2021 Jun 11.

Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology Jiangsu Ocean University Lianyungang China.

In the present study, a DNAzyme was screened in vitro through the use of a DNA library and crude extracellular mixture (CEM) of . Following eight rounds of selection, a DNAzyme termed PAE-1 was obtained, which displayed high rates of cleavage with strong specificity. A fluorescent biosensor was designed for the detection of in combination with the DNAzyme. A detection limit as low as 1.2 cfu/ml was observed. Using proteases and filtration, it was determined that the target was a protein with a molecular weight of 10 kDa-50 kDa. The DNAzyme was combined with a polystyrene board to construct a simple indicator plate sensor which produced a color that identified the target within 10 min. The results were reliable when tap water and food samples were tested. The present study provides a novel experimental strategy for the development of sensors based on a DNAzyme to rapidly detect in the field.
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http://dx.doi.org/10.1002/fsn3.2367DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8269565PMC
July 2021

The biological responses and mechanisms of endothelial cells to magnesium alloy.

Regen Biomater 2021 Jun 28;8(3):rbab017. Epub 2021 May 28.

National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, China.

Due to its good biocompatibility and degradability, magnesium alloy (Mg alloy) has shown great promise in cardiovascular stent applications. Rapid stent re-endothelialization is derived from migrated and adhered endothelial cells (ECs), which is an effective way to reduce late thrombosis and inhibit hyperplasia. However, fundamental questions regarding Mg alloy affecting migration and adhesion of ECs are not fully understood. Here, we evaluated the effects of Mg alloy on the ECs proliferation, adhesion and migration. A global gene expression profiling of ECs co-culturing with Mg alloy was conducted, and the adhesion- and migration-related genes were examined. We found that Mg alloy had no adverse effects on ECs viability but significantly affected ECs migration and adhesion. Co-cultured with Mg alloy extract, ECs showed contractive adhesion morphology and decreased motility, which was supported by the down-regulation of adhesion-related genes ( and ) and migration-related genes ( and ). Accordingly, the re-endothelialization of Mg alloy stent was inhibited . Our results may provide new inspiration for improving the broad application of Mg alloy stents.
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http://dx.doi.org/10.1093/rb/rbab017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8240605PMC
June 2021

Detection of in Seafood With a DNAzyme-Based Biosensor.

Front Microbiol 2021 4;12:655845. Epub 2021 Jun 4.

Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China.

is an important pathogenic bacterium that is often associated with seafood-borne illnesses. Therefore, to detect this pathogen in aquatic products, a DNAzyme-based fluorescent sensor was developed for the detection of . After screening and mutation, a DNAzyme that we denominated "RFD-VV-M2" exhibited the highest activity, specificity, and sensitivity. The limit of detection was 2.2 × 10 CFU/ml, and results could be obtained within 5-10 min. Our findings suggested that the target of DNAzyme RFD-VV-M2 was a protein with a molecular weight between 50 and 100 kDa. The proposed biosensor exhibited an excellent capacity to detect marine products contaminated with . Therefore, our study established a rapid, simple, sensitive, and highly specific detection method for in aquatic products.
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http://dx.doi.org/10.3389/fmicb.2021.655845DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8213197PMC
June 2021

Utility of multi-parametric quantitative magnetic resonance imaging of the lacrimal gland for diagnosing and staging Graves' ophthalmopathy.

Eur J Radiol 2021 Aug 8;141:109815. Epub 2021 Jun 8.

Department of Endocrinology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510080, Guangdong Province, China. Electronic address:

Purpose: To explore radiological changes of the lacrimal gland (LG) in Graves' ophthalmopathy (GO) based on multi-parametric quantitative MRI and its clinical utility in LG diagnosis and activity in GO.

Methods: We enrolled 99 consecutive patients with GO (198 eyes) and 12 Graves' Disease (GD) patients (24 eyes) from July 2018 to June 2020. Clinical, laboratory, and MRI data were collected at the first visit. Based on clinical activity scores, eyes with GO were subdivided into active and inactive groups. T2-relaxation time (T2) and the absolute reduction in T1-relaxation time (ΔT1) were determined. After MRI and processing, we performed descriptive data analysis and group comparisons. Novel logistic regression predictive models were developed for diagnosing and staging GO. Diagnostic performance of MRI parameters and models was assessed by receiver operating characteristic curve analysis.

Results: LG in GO group had significantly higher T2 and ΔT1 values than the GD group [106.25(95.30,120.21) vs. 83.35(78.15,91.45), P<0.001, and 662.62(539.33,810.95) vs. 547.35(458.62,585.57), P = 0.002, respectively]. The GO group had higher T2 of LG indicating higher disease activity [110.93(102.54,127.67) vs. 93.29(87.06,101.96), P < 0.001]. Combining T2 and ΔT1 values of LG, Model I had higher diagnostic value for distinguishing GO from GD (AUC=0.94, 95 %CI: 0.89,0.99, P<0.001). Meanwhile, T2 of LG had higher diagnostic value for grading GO activity (AUC = 0.84, 95 %CI: 0.76,0.92, P<0.001).

Conclusions: Multi-parametric quantitative MRI parameters of the LG in GO were significantly altered. Novel models combining LG T2 and ΔT1 values showed excellent predictive performances in diagnosing GO. Furthermore, T2 of LG showed practical utility for staging GO.
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http://dx.doi.org/10.1016/j.ejrad.2021.109815DOI Listing
August 2021

Antibiotics armed neutrophils as a potential therapy for brain fungal infection caused by chemotherapy-induced neutropenia.

Biomaterials 2021 07 11;274:120849. Epub 2021 May 11.

Shanghai Tenth People's Hospital, Department of Medical Ultrasound, Department of Pharmacology, Tongji University School of Medicine, Shanghai, 200092, PR China. Electronic address:

Chemotherapy-induced neutropenia, a symptom of neutrophil depletion, makes cancer patients highly susceptible to invasive fungal infection with substantial morbidity and mortality. To address the cryptococcal brain infection in this condition, this study attempts to arm neutrophils (NEs) with antibiotics to potentiate the antifungal capability of NEs. To allow effective integration, amphotericin B, a potent antibiotic, is assembled with albumin nanoparticles through hydrophobic and hydrogen-bond interactions to form [email protected] nanoparticles (A-NPs). The nutrient composition (albumin) and virus-like size (~40 nm) facilitate efficient uptake of A-NPs by NEs to construct the antibiotics-armed NEs. It is demonstrated that the armed NEs can maintain the intrinsic biological functions of NEs, such as cell viability and capacity of migration to an inflammatory site. In a neutropenic mouse model of brain fungal infection, the treatment with the armed NEs allows for preventing fungal invasion more effectively than that with the native NEs, without the apparent systemic toxicity. Such a synergistic anti-infection system maximizes the antifungal effects by taking advantage of NEs and antibiotics. It provides a potential NEs-mediated therapeutic approach for treating fungal infection caused by chemotherapy-induced neutropenia.
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http://dx.doi.org/10.1016/j.biomaterials.2021.120849DOI Listing
July 2021

Exploring the interactions of naringenin and naringin with trypsin and pepsin: Experimental and computational modeling approaches.

Spectrochim Acta A Mol Biomol Spectrosc 2021 Sep 21;258:119859. Epub 2021 Apr 21.

School of Medical Engineering, Xinxiang Medical University, Xinxiang, Henan 453003, PR China. Electronic address:

Naringenin and naringin are two natural compounds with important health benefits, whether as food or drug. It is necessary to study the interactions between naringenin/naringin and digestive proteases, such as trypsin and pepsin. In this study, the bindings of naringenin and naringin to trypsin and pepsin were investigated using multi-spectroscopy analysis and computational modeling approaches. Fluorescence experiments indicate that both naringenin and naringin can quench the intrinsic fluorescence of trypsin/pepsin via static quenching mechanism. Naringin binds trypsin/pepsin in a more firmly way than naringenin. Thermodynamic analysis reveals that the interactions of naringenin/naringin and trypsin/pepsin are synergistically driven by enthalpy and entropy, and the major driving forces are hydrophobic, electrostatic interactions and hydrogen bonding. Synchronous fluorescence spectroscopy, circular dichroism spectroscopy and FT-IR show that naringenin/naringin may induce microenvironmental and conformational changes of trypsin and pepsin. Molecular docking reveals that naringenin binds in the close vicinity of the active site (Ser-195) of trypsin and Asp-32 (the catalytic activity of pepsin) appears in naringin-pepsin system. The direct interactions between naringenin or naringin and catalytic amino acid residues will inhibit the catalytic activity of trypsin and pepsin, respectively. The results of molecular dynamic simulation validate the reliability of the docking results.
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http://dx.doi.org/10.1016/j.saa.2021.119859DOI Listing
September 2021

Landscape scaling of different land-use types, geomorphological styles, vegetation regionalizations, and geographical zonings differs spatial erosion patterns in a large-scale ecological restoration watershed.

Environ Sci Pollut Res Int 2021 Jul 17;28(28):38374-38392. Epub 2021 Mar 17.

Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.

Water erosion is one of the main types of soil degradation, but few quantitative estimates have been done in the soil erosion intensity grades of different landscape scaling characteristics in a large-scale ecological restoration watershed. This study comparatively illustrates the utility of high-resolution data and geospatial technique, particularly the GIS-based RUSLE model, for an improved understanding of the spatial patterns of soil erosion under different land use types, geomorphological styles, vegetational regionalizations, and geographical zonings, aiming to promote ecological sustainable watershed management in practice. Results indicate the following:(i) The soil erosion intensity grade showed an overall decreasing trend from northwest to southeast in the Jinghe River Watershed. The percentages of intense erosion and extremely intense erosion in different land use types in 2015 were significantly lower than that in 2000 except middle- and low-coverage grasslands because of the effective implementation of "Grain for Green" project. e.g., the percentage of extremely intense erosion in dry land decreased from 41.72% in 2000 to 8.99% in 2015.(ii) The mid-elevation loessial beams and hills and mid-elevation loessial tableland were both the major sources of intense erosion and extremely intense erosion, with the contribution ratio of 41.89 and 53.94% and 35.79 and 20.83% in 2000 and 44.45 and 48.99% and 36.88 and 18.72% in 2015, respectively.(iii) The intense, extremely intense and severe erosion in the temperate typical grassland subzone accounted for 32.62, 44.47, and 9.6% in 2000 and 36.74, 40.7, and 8.1% in 2015, respectively. There were no severe and extremely intense erosion in the deciduous oak forest subzone of northern and southern warm temperate. (iv) The intense, extremely intense, and severe erosion of the loessial wide valley hills accounted for 32.19, 45.27, and 8.92% in 2000 and 36.32, 41.42, and 7.48% in 2015. The intense and extremely intense erosion of the loessial tableland accounted for 40.58 and 16.02% in 2000 and 40.57 and 14.27% in 2015. More importantly, land use types can be applied to the design and implementation of a development scheme more reliably than other landscapes because the land use system is a more scientific and fine classification based on topography, soils, and vegetation correlated with geology, geomorphology, and climate. The knowledge on the fine landscape scale will be useful for comprehensive watershed management by soil scientists, agronomists, environmental scientists, land managers, and policymakers.
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http://dx.doi.org/10.1007/s11356-021-13274-1DOI Listing
July 2021

β-Amyloid Peptide 1-42-Conjugated Magnetic Nanoparticles for the Isolation and Purification of Glycoproteins in Egg White.

ACS Appl Mater Interfaces 2021 Mar 17;13(12):14028-14036. Epub 2021 Mar 17.

Institute of Translational Medicine, Department of Pharmacy, Shenyang Medical College, Shenyang 110034, China.

Aβ-conjugated magnetic nanoparticles, Aβ@MNP, were prepared by covalently coupling Aβ to hyperbranched polyethyleneimine (PEI)-modified magnetic nanoparticles via -(3-dimethylaminopropyl)-'-ethylcarbodiimide hydrochloride (EDC). Aβ's high binding capacity to glycosyl groups facilitates Aβ@MNP composite to be a promising selective adsorbent for glycoproteins in egg whites. In our study, under conditions of pH 4.0, the adsorption efficiency of Aβ@MNP composite for ovalbumin (100 μg mL) was 98.4% and its maximum adsorption capacity was 344.8 mg g ; under the condition of pH 4.0 and 200 mmol L NaCl, its adsorption efficiencies for ovalbumin and ovotransferrin were 96.9% and 60.0%, respectively. According to these primary data, in practice, ovalbumin was removed from egg white by Aβ@MNP composite at pH 4.0 (step I), and then after adding NaCl until the final salt concentration reached 200 mmol L (pretreated egg white), we utilized the same adsorbent to further isolate/purify glycoproteins (step II). SDS-PAGE results showed that Aβ@MNP composite could largely remove ovalbumin in step I and could isolate/purify the remaining ovalbumin and ovotransferrin in step II. LC-MS/MS analysis results showed that the removal of ovalbumin reduced its percentage in egg white samples from 32.93% to 11.05% in step I and the remaining ovalbumin and ovotransferrin were enriched in step II, where the final percentage reached 11.6% and 12.6%, respectively. In summary, 81 protein species were identified after two-step extraction with Aβ@MNP on egg white, while only 46 protein species were identified directly from raw egg white without any pretreatment. This work well illustrates the excellent adsorption performance of Aβ@MNP composite to glycoproteins and its potential in the application of proteomic studies on low-abundance proteins in egg white.
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http://dx.doi.org/10.1021/acsami.1c02356DOI Listing
March 2021

Metformin restores hippocampal neurogenesis and learning and memory via regulating gut microbiota in the obese mouse model.

Brain Behav Immun 2021 07 18;95:68-83. Epub 2021 Feb 18.

Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology (HUST), Wuhan 430074, China; Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan 430030, China. Electronic address:

Numerous studies have shown that over-nutritional obesity may lead to pre-diabetes, type 2 diabetes and cognitive decline. As the degree of metabolic disorders increases, the cognitive decline is getting worse. However, the cellular events that cause this cognitive dysfunction is yet to be clarified. We used a high-fat diet (HFD) consumption-induced obesity mouse model to test the effects of metformin on the hippocampal neurogenesis and learning and memory abilities of obese mice. 5-Bromo-2'-deoxyuridine (BrdU) labelling and retrovirus labeling were applied to detect hippocampal newborn neurons. Behavioral experiments were used to detect learning and memory abilities of mice. 16S rRNA gene sequencing was performed to detect the composition of gut microbiota. The positron emission tomography (PET) was conducted to detect the energy metabolism activity of different mouse brain regions. Our results reveal that metformin restores the impairment of neurogenesis in the dentate gyrus and finally prevents the cognitive decline of the obese mice. Moreover, the therapeutic effects of metformin are achieved by regulating the composition of gut microbiota of mice, which may inhibit microglia activation and neuroinflammation in the brain of obese mice. This study suggests that metformin may be taken as a promising candidate for the intervention of cognitive decline related to imbalance of gut microbiota caused by obesity.
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http://dx.doi.org/10.1016/j.bbi.2021.02.011DOI Listing
July 2021

Rapid Detection of by the Naked Eye Using DNA Aptamers.

ACS Omega 2021 Feb 21;6(5):3771-3779. Epub 2021 Jan 21.

Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang 222005, PR China.

was first isolated from gastritis patients by Barry J. Marshall and J. Robin Warren in 1982, and more than 90% of duodenal ulcers and about 80% of gastric ulcers are caused by infection. Most detection methods require sophisticated instruments and professional operators, making detection slow and expensive. Therefore, it is critical to develop a simple, fast, highly specific, and practical strategy for the detection of . In this study, we used as a target to select unique aptamers that can be used for the detection of . In our study, we used random ssDNA as an initial library to screen nucleic acid aptamers for . We used binding rate and the fluorescence intensity to identify candidate aptamers. One DNA aptamer, named HPA-2, was discovered through six rounds of positive selection and three rounds of negative selection, and it had the highest affinity constant of all aptamers tested ( = 19.3 ± 3.2 nM). This aptamer could be used to detect and showed no specificity for other bacteria. Moreover, we developed a new sensor to detect with the naked eye for 5 min using illumination from a hand-held flashlight. Our study provides a framework for the development of other aptamer-based methods for the rapid detection of pathogenic bacteria.
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http://dx.doi.org/10.1021/acsomega.0c05374DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7876845PMC
February 2021

Hydrothermal combination and geometry control the spatial and temporal rhythm of glacier flow.

Sci Total Environ 2021 Mar 9;760:144315. Epub 2020 Dec 9.

Gansu Academy of Eco-environment Sciences, Lanzhou 730000, China.

The dynamic response of glacier to atmospheric change has varied both spatially and temporally. While some of this variability is likely related to regional climate signals, the geometry of this particular glacier also appears to be important. In this study, we investigated the hydrothermal conditions and geometric controls on the temporal and spatial evolution of Baishui River Glacier No.1's velocity from 2012 to 2019. To do this, we combined field investigations and remote sensing observations to measure the velocity of the glacier, and factors controlling this velocity. Annual changes showed that, from 2012 to 2019, the Baishui River Glacier No. 1 experienced continuous shrinkage, accompanied by decreasing ice velocities. Seasonal changes showed that the glacier velocity during the monsoon period was significantly higher than during the non-monsoon period. Spatially, the glacier's dynamic variability decreased toward its terminus, but increased toward the upper reaches of the glacier, along a longitudinal axis. We would suggest that the interannual velocity variation of Baishui River Glacier No.1 corresponded to thinning of the glacier, which in turn affected its gravitational force. Given that surface melt-induced basal lubrication, basal friction controlled by freezing rate, and dynamic thickening can alter seasonal patterns of movement, these variations may be important for understanding the seasonal evolution of this, and other glaciers. Our results further indicated that glacier width, slope, surface meltwater and crevasses were important constraints on any spatial movement patterns.
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http://dx.doi.org/10.1016/j.scitotenv.2020.144315DOI Listing
March 2021

A novel mechanism of inhibiting in-stent restenosis with arsenic trioxide drug-eluting stent: Enhancing contractile phenotype of vascular smooth muscle cells via YAP pathway.

Bioact Mater 2021 Feb 4;6(2):375-385. Epub 2020 Sep 4.

Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, 400030, China.

Objective: Arsenic trioxide (ATO or AsO) has beneficial effects on suppressing neointimal hyperplasia and restenosis, but the mechanism is still unclear. The goal of this study is to further understand the mechanism of ATO's inhibitory effect on vascular smooth muscle cells (VSMCs).

Methods And Results: Through cell culture and stent implanting into the carotid arteries of rabbit, a synthetic-to-contractile phenotypic transition was induced and the proliferation of VSMCs was inhibited by ATO. F-actin filaments were clustered and the elasticity modulus was increased within the phenotypic modulation of VSMCs induced by ATO . Meanwhile, Yes-associated protein (YAP) nuclear translocation was inhibited by ATO both and . It was found that ROCK inhibitor or YAP inactivator could partially mask the phenotype modulation of ATO on VSMCs.

Conclusions: The interaction of YAP with the ROCK pathway through ATO seems to mediate the contractile phenotype of VSMCs. This provides an indication of the clinical therapeutic mechanism for the beneficial bioactive effect of ATO-drug eluting stent (AES) on in-stent restenosis (ISR).
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http://dx.doi.org/10.1016/j.bioactmat.2020.08.018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7484501PMC
February 2021

ACE2 modulates glucose homeostasis through GABA signaling during metabolic stress.

J Endocrinol 2020 09;246(3):223-236

Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.

The angiotensin-converting enzyme 2 (ACE2)/angiotensin 1-7 (A1-7)/MAS axis and glutamate decarboxylase 67 (GAD67)/gamma-aminobutyric acid (GABA) signal both exist in the islet and play important roles in regulating blood glucose metabolism. It has been reported that the activation of ACE2 in the brain increases GABA expression to improve biological effects; however, it is unclear whether there is functional correlation between the ACE2/A1-7/MAS axis and GAD67/GABA signal in the islet. In this study, we showed that the ACE2/A1-7/MAS and GABA signaling systems decreased in the islet of different metabolic stress models. In ACE2-knockout mice, we found that GAD67 and GABA expression decreased significantly, which was reversed by exogenous administration of A1-7. Furthermore, A1-7 mediated PDX1 and AKT activation was inhibited by allylglycine (a specific GAD67 inhibitor) in MIN6 cells. Moreover, giving A1-7 and GABA could significantly reduce beta-cell dedifferentiation and improved glucose metabolism during metabolic stress in vivo and in vitro. In conclusion, our study reveals that the ACE2/A1-7/MAS axis improves beta-cell function through regulating GAD67/GABA signal in beta cells and that up-regulating the ACE2/A1-7/MAS axis and GABA signals delays the development of obesity-induced diabetes.
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http://dx.doi.org/10.1530/JOE-19-0471DOI Listing
September 2020

Long-Term Liraglutide Administration Induces Pancreas Neogenesis in Adult T2DM Mice.

Cell Transplant 2020 Jan-Dec;29:963689720927392

Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, P.R. China.

In vivo beta-cell neogenesis may be one way to treat diabetes. We aimed to investigate the effect of glucagon-like peptide-1 (GLP-1) on beta-cell neogenesis in type 2 diabetes mellitus (T2DM). Male C57BL/6J mice, 6 wk old, were randomly divided into three groups: Control, T2DM, and T2DM + Lira. T2DM was induced using high-fat diet and intraperitoneal injection of streptozotocin (40 mg/kg/d for 3 d). At 8 wk after streptozotocin injection, T2DM + Lira group was injected intraperitoneally with GLP-1 analog liraglutide (0.8 mg/kg/d) for 4 wk. Apparently for the first time, we report the appearance of a primitive bud connected to pancreas in all adult mice from each group. The primitive bud was characterized by scattered single monohormonal cells expressing insulin, GLP-1, somatostatin, or pancreatic polypeptide, and four-hormonal cells, but no acinar cells and ductal epithelial cells. Monohormonal cells in it were small, newborn, immature cells that rapidly proliferated and expressed cell markers indicative of immaturity. In parallel, Ngn3 endocrine progenitors and Nestin cells existed in the primitive bud. Liraglutide facilitated neogenesis and rapid growth of acinar cells, pancreatic ducts, and blood vessels in the primitive bud. Meanwhile, scattered hormonal cells aggregated into cell clusters and grew into larger islets; polyhormonal cells differentiated into monohormonal cells. Extensive growth of exocrine and endocrine glands resulted in the neogenesis of immature pancreatic lobes in adult mice of T2DM + Lira group. Contrary to predominant acinar cells in mature pancreatic lobes, there were still a substantial number of mesenchymal cells around acinar cells in immature pancreatic lobes, which resulted in the loose appearance. Our results suggest that adult mice preserve the capacity of pancreatic neogenesis from the primitive bud, which liraglutide facilitates in adult T2DM mice. To our knowledge, this is the first time such a phenomenon has been reported.
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http://dx.doi.org/10.1177/0963689720927392DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7563804PMC
June 2021

Comparative studies on the interaction of nine flavonoids with trypsin.

Spectrochim Acta A Mol Biomol Spectrosc 2020 Sep 4;238:118440. Epub 2020 May 4.

Grade 2018, School of Pharmacy, Xinxiang Medical University, Xinxiang, Henan 453003, PR China.

In this study, the interaction between nine classic flavonoids (including baicalin, quercetin, myricetin, rutin, puerarin, daidzein, liquiritin and isoliquiritin) and trypsin was investigated by fluorescence spectroscopy and molecular modeling methods. The results reveal that all flavonoids can interact with trypsin to form flavonoid-trypsin complexes. The binding parameters obtained from the data at different temperatures indicate that all flavonoids can spontaneously bind with trypsin with one binding site. The binding constants of trypsin with nine classic flavonoids are in the following order as: baicalin > myricetin > rutin > isoliquiritin > hesperidin > puerarin > quercetin > daidzein > liquiritin. The interaction forces between flavonoids and trypsin may be electrostatic forces (except for rutin/puerarin/daidzein), hydrophobic interactions as well as van der Waals forces. Synchronous fluorescence spectroscopy shows that the interaction between flavonoids and trypsin changes the hydrophobicity of the microenvironment of tryptophan (Trp) residues. All flavonoids close to tyrosine (Tyr) residues but have no effect on the microenvironment around Tyr residues except for hesperidin and liquiritin. Molecular modeling displays that all flavonoids bind directly into trypsin cavity site and lead to a decrease in enzyme activity.
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http://dx.doi.org/10.1016/j.saa.2020.118440DOI Listing
September 2020

Liraglutide Attenuates Non-Alcoholic Fatty Liver Disease in Mice by Regulating the Local Renin-Angiotensin System.

Front Pharmacol 2020 8;11:432. Epub 2020 Apr 8.

Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.

The renin-angiotensin system (RAS) is involved in the pathogenesis of non-alcoholic fatty liver disease (NAFLD) and represents a potential therapeutic target for NAFLD. Glucagon-like peptide-1 (GLP-1) signaling has been shown to regulate the RAS within various local tissues. In this study, we aimed to investigate the functional relationship between GLP-1 and the local RAS in the liver during NAFLD. Wild-type and ACE2 knockout mice were used to establish a high-fat-induced NAFLD model. After the mice were treated with liraglutide (a GLP-1 analogue) for 4 weeks, the key RAS component genes were up-regulated in the liver of NAFLD mice. Liraglutide treatment regulated the RAS balance, preventing a reduction in fatty acid oxidation gene expression and increasing gluconeogenesis and the expression of inflammation-related genes caused by NAFLD, which were impaired in ACE2 knockout mice. Liraglutide-treated HepG2 cells exhibited activation of the ACE2/Ang1-7/Mas axis, increased fatty acid oxidation gene expression, and decreased inflammation, which could be reversed by A779 and AngII. These results indicate that the local RAS in the liver becomes overactivated in response to NAFLD. Moreover, ACE2 knockout increases the severity of liver steatosis. Liraglutide has a negative and antagonistic effect on the ACE/AngII/AT1R axis, a positive impact on the ACE2/Ang1-7/Mas axis, and is mediated through the PI3K/AKT pathway. This may represent a potential new mechanism by which liraglutide improves NAFLD.
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http://dx.doi.org/10.3389/fphar.2020.00432DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7156971PMC
April 2020

FRET investigation toward DNA tetrahedron-based ratiometric analysis of intracellular telomerase activity.

J Mater Chem B 2019 03 15;7(11):1926-1932. Epub 2019 Feb 15.

Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou 215163, P. R. China.

Telomerase catalyzes the elongation of telomeres, which is closely associated with tumorigenesis. Therefore, development of reliable and convenient methods for telomerase activity analysis is critical for clinical diagnosis of cancers. However, most of the current probes for intracellular telomerase activity assay suffer from inevitable false-positive interferences. In this study, we have proposed a novel fluorescence resonance energy transfer (FRET)-based strategy for ultrasensitive monitoring intracellular telomerase activity with an amplification-free procedure. DNA nanoprobes constructed using a DNA tetrahedron and Flare DNA are designed to circumvent the problem of false-positive interference. Generally, telomerase catalyzes DNA extension and changes the configuration of the DNA nanoprobe, which finally leads to the increase of the distance between two labelled fluorophores. Based on the notably decreased FRET efficiency, a simple ratiometric sensor is established for the detection of telomerase activity at the single-cell level, which is much suitable for clinical applications. In addition, this method can be further applied in the detection of telomerase inhibitors, which is important for anti-cancer drug discovery.
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http://dx.doi.org/10.1039/c9tb00001aDOI Listing
March 2019

Silver [email protected] tetrahedron-based colorimetric detection of HIV-related DNA with cascade strand displacement amplification.

Authors:
Xiaoyi Ma Peng Miao

J Mater Chem B 2019 04 20;7(16):2608-2612. Epub 2019 Mar 20.

University of Science and Technology of China, Hefei 230026, China.

DNA tetrahedron-modified silver nanoparticles (AgNPs) were achieved via amino-silver chemistry for the first time and were applied as a colorimetric biosensor for detecting HIV-related DNA. Target DNA initiated strand displacement polymerization and nicking endonuclease-aided cycles were involved to link DNA tetrahedron-modified AgNPs, reporting colorimetric responses. This developed method showed excellent specificity and sensitivity. A wide linear range from 1 to 15 000 nM was achieved with a limit of detection of 0.84 nM. Moreover, it was successfully applied to determine DNA in blood serum samples.
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http://dx.doi.org/10.1039/c9tb00274jDOI Listing
April 2019

Is the correlation between hydro-environmental variables consistent with their own time variability degrees in a large-scale loessial watershed?

Sci Total Environ 2020 Jun 14;722:137737. Epub 2020 Mar 14.

Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A&F University, Yangling, Shaanxi 712100, PR China; College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, Shaanxi 712100, PR China. Electronic address:

Temporal scale is an important keyword in environmental hydrology but little information is available in the relationship between correlation and time variability degree of hydro-environmental variables at a watershed scale, which makes it difficult to design effective real-time management strategies. Here we take the Yanhe River Watershed as a study case to simulate and inventory the fractal characteristics of correlation and time variability degree of runoff, rainfall, and NH-N at different time scales, focusing on the long-term series of 1984-2012. (i) The coupled modeling framework based on SWAT (Soil and Water Assessment Tool), statistics and fractal theory is a time series analysis method that is particularly suitable for the evaluation of long-range correlation of non-linear time series. The Nash-Sutcliffe Efficiency coefficient (NSE), R and PBIAS during the calibration and verification period proved the reliability and acceptability of the established SWAT model in modeling multi-time scale runoff and NH-N load in the upstream catchment of Ganguyi hydrological station. (ii) Runoffs at all time scales showed positive correlations with rainfall although the significant level had a certain time scale differences. More interestingly, the correlation between NH-N loss and runoff at different time scales was significantly higher than that of rainfall. (iii) Each hydro-environmental variable has different fractal and time variation characteristics at different time scales, and the correlation levels between different hydrological variables are not completely consistent with their own time variability degrees at different time scales. These findings point to a fundamental challenge in managing regions with leading infiltration-excess runoff and uneven nutrient loading because the meteorological and hydrological variables in these regions exhibit the strongest temporal variability, which will affect the effective allocation and implementation in management practices.
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http://dx.doi.org/10.1016/j.scitotenv.2020.137737DOI Listing
June 2020

Using five long time series hydrometeorological data to calibrate a dynamic sediment delivery ratio algorithm for multi-scale sediment yield predictions.

Environ Sci Pollut Res Int 2020 May 2;27(14):16377-16392. Epub 2020 Mar 2.

Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China.

The sediment delivery ratio (SDR) is a key link between slope erosion and river sediment transport but the accurate quantification of sediment yield in different catchments has been hampered by a lack of dynamic multi-scale information on SDR. A dynamic multi-scale SDR algorithm was innovatively applied in the modified sediment yield model to quantify the spatiotemporal evolutions of sediment delivery and inventory the relationships between sediment yield and different hydrometeorological and landscape factors in the loess hilly and gully catchment. Results indicate that (i) The sloping farmland (dry lands in hilly areas) in the upstream catchment of Ansai hydrological station was an important sediment source because its soil erosion grade was between intensive and extremely intensive. The high-risk regions of sediment yield were primarily concentrated in the sloping farmlands locating at both sides of the river banks. (ii) The large-scale soil conservation practices since the late 1990s have played a very significant role in sediment reduction. The annual sediment yield rate showed an overall decreasing trend from 1981 to 2015, particularly, it decreased dramatically from 11,844.08 t•km in 2005 to 65 t•km in 2015. (iii) The correlations between SDR and sediment yield rate, maximum peak flow, or runoff amount were all greater than that of rainfall parameters, indicating that there was no direct causal relationship between SDR and rainfall indicators in loessial ecological restoration watersheds. Results provide scientific insights needed to guide model modifications and sustainable soil conservation planning in the Loess Plateau.
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http://dx.doi.org/10.1007/s11356-020-08121-8DOI Listing
May 2020

Ratiometric fluorescence method for ctDNA analysis based on the construction of a DNA four-way junction.

Analyst 2020 Feb;145(4):1174-1178

CAS Key Lab of Bio-Medical Diagnostics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, China.

We present a novel ratiometric fluorescent biosensor for ctDNA analysis based on the construction of a DNA four-way junction (FWJ). Three fuel strands for the FWJ are firstly designed and prepared. Another essential strand for the formation of the structure is the DNA product generated from target ctDNA initiated strand displacement amplification. With the transformation of the DNA structure, the FRET states of two fluorophores change and the ratiometric fluorescence response can be recorded to indicate the level of the initial ctDNA. The proposed method also has excellent capability to discriminate mismatches and shows potential practical utility for clinical samples.
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http://dx.doi.org/10.1039/d0an00044bDOI Listing
February 2020

Using vegetation correction coefficient to modify a dynamic particulate nutrient loss model for monthly nitrogen and phosphorus load predictions: a case study in a small loess hilly watershed.

Environ Sci Pollut Res Int 2019 Nov 19;26(31):32610-32623. Epub 2019 Oct 19.

Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A&F University, Yangling, 712100, People's Republic of China.

Vegetation is an important factor affecting nutrient enrichment ratio in runoff sediments but few studies have been examined in the effects of different vegetation scenarios on the monthly evolutions of particulate nitrogen (N) and phosphorus (P) loss. In this study, a vegetation correction coefficient was innovatively embedded in a dynamic particulate nutrient loss model to evaluate the monthly trends of particulate N and P loss in a small highly erodible watershed. Results indicate that (i) the monthly sediment yield from June to August 2013 accounted for the dominant percentage in this extreme hydrological year, which was consistent with the monthly trends of rainfall erosivity. The largest monthly sediment yield rate under four different vegetation scenarios all occurred in July with the values of 530.56, 258.09, 579.69, and 370.74 t km. (ii) Particulate N and P loss from April to September changed significantly under different vegetation scenarios, and they were mainly concentrated in June and July 2013; only the N and P loss loads in July accounted for > 70% of annual load. However, the loads in January, February, March, October, November, and December were considered as zero because there was no erosive rainfall during the above 6 months. (iii) The reduction efficiency of particulate N and P loss by scenario 1 was about 1.7 times higher than scenario 3, which shows that forestland in sediment reduction was stronger than grassland and cropland in Zhifanggou Watershed. Results provide the underlying insights needed to guide vegetation reconstruction and soil conservation planning in loess hilly regions.
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http://dx.doi.org/10.1007/s11356-019-06564-2DOI Listing
November 2019

Triple-Input Molecular AND Logic Gates for Sensitive Detection of Multiple miRNAs.

ACS Appl Mater Interfaces 2019 Nov 28;11(44):41157-41164. Epub 2019 Oct 28.

Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences , Suzhou 215163 , People's Republic of China.

Abnormal miRNA expressions are closely related to the occurrence and development of cancers. It is of great significance to monitor miRNA expression levels for early diagnosis and therapy of the diseases. This study presents two independent colorimetric strategies for simultaneously monitoring multiple miRNAs based on cross-linking or non-cross-linking aggregations of gold nanoparticles (AuNPs). By introducing a Y shaped DNA structure and two types of DNA modified AuNPs, a triple-input DNA AND logic gate is facilely developed with the cross-linking aggregation of AuNPs as the signal output. To improve the sensitivity and shorten reaction time, the logic gate is modified by further employing a three DNA strands formed duplex and hybridization chain reaction. Non-cross-linking aggregation of AuNPs is used to evaluate the concentration of initial miRNA inputs. This strategy does not require DNA modification of AuNPs and ultrahigh sensitivity is achieved with the amplification of hybridization chain reaction. The present work may provide powerful tools for multiple miRNAs diagnostics and inspire further development of DNA based logic gates.
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http://dx.doi.org/10.1021/acsami.9b16812DOI Listing
November 2019

Recognition of Helicobacter pylori by protein-targeting aptamers.

Helicobacter 2019 Jun 4;24(3):e12577. Epub 2019 Apr 4.

Jiangsu Key Laboratory of Marine Bioresources and Environment, Huaihai Institute of Technology, Lianyungang, China.

Background: Helicobacter pylori (H pylori) is a disease-causing pathogen capable of surviving under acidic conditions of the human stomach. Almost half of the world's population is infected with H pylori, with gastric cancer being the most unsatisfactory prognosis. Although H pylori has been discovered 30 years ago, the effective treatment and elimination of H pylori continue to be problematic.

Materials And Methods: In our study, we screened nucleic acid aptamers using H pylori surface recombinant antigens as targets. Trypsin was used for separating aptamers that were bound to proteins. Following nine rounds of screening, we performed sequence similarity analyses to assess whether the aptamers can recognize the target protein. Two sequences with desirable recognition ability were selected for affinity detection. Aptamer Hp4 with the strongest binding ability to the H pylori surface recombinant antigen was chosen. After optimization of the binding conditions, we conducted specificity tests for Hp4 using Escherichia coli, Staphylococcus aureus, Vibrioanguillarum, and H pylori.

Results: The data indicated that the aptamer Hp4 had an equilibrium dissociation constant (K ) of 26.48 ± 5.72 nmol/L to the target protein. This aptamer was capable of exclusively detecting H pylori cells, without displaying any specificity for other bacteria.

Conclusions: We obtained a high-affinity aptamer for H pylori, which is expected to serve as a new molecular probe for detection of H pylori.
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http://dx.doi.org/10.1111/hel.12577DOI Listing
June 2019

Experiment and simulation of supersaturated total dissolved gas dissipation: Focus on the effect of confluence types.

Water Res 2019 May 2;155:320-332. Epub 2019 Mar 2.

Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A&F University, Yangling, Shaanxi, 712100, China.

Total dissolved gas supersaturation (TDGS) downstream caused by spill discharge from high dams can easily cause fish to suffer from gas bubble disease (GBD). One potential approach to mitigate the impact of TDGS is at the confluence of a downstream tributary, where the introduction of low-TDG water might provide refuge space for fish. In this study, we carried out a series of flume experimental cases and established a three-dimensional TDGS model at confluences. The formula of the dissipation coefficient of TDGS had been obtained by parts of experiment cases. The other parts of experimental cases were carried out to validate the established TDGS model. The biggest relative error of TDG concentration between the experiment and simulation was -5.7%. The results show that the convergence of tributary water (TDG = 100%) can affect the mainstream water (TDG = 140% ∼ 150%) significantly. The two most obvious features are the presence of the separation zone and secondary flow which become more significant as the flow rate increases. The separation zone area at the bottom is smaller than that at the surface. There are two secondary circulations on transversal planes which decrease as the longitudinal distance increases. In addition, the area below 110% and 120% of TDGS in different planes of different cases were compared in detail. This study can provide scientific basis for the utilization of the low-TDG-saturation region to protect fish from the damage of TDGS at confluences during high dam discharge.
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http://dx.doi.org/10.1016/j.watres.2019.02.056DOI Listing
May 2019

Arsenic Trioxide-Coated Stent Is an Endothelium-Friendly Drug Eluting Stent.

Adv Healthc Mater 2018 08 16;7(15):e1800207. Epub 2018 May 16.

Key Laboratory for Biorheological Science and Technology of Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, Bioengineering College of Chongqing University, Chongqing, 400030, China.

An ideal vascular stent would both inhibit in-stent restenosis (ISR) and promote rapid re-endothelialization. In the current study, the performance of arsenic trioxide (ATO)-drug eluting stent (AES) is compared with the bare metal stent, poly-lactic-co-glycolic acid-coating metal stent, and rapamycin-drug eluting stent (RES). In vivo AES is shown to prevent neointimal hyperplasia more efficiently than the others when implanted into the carotid arteries of rabbits. Moreover, AES promotes endothelial cells proliferation and re-endothelialization more quickly than RES. In vitro ATO exposure significantly increases the viability, proliferation, adhesion, and spreading of primary porcine coronary artery endothelial cells (PCAECs), which are critical for endothelialization. However, ATO exposure reduces the viability of porcine coronary artery smooth muscle cells (PCASMCs). The evaluation of mitochondrial morphology, membrane potential, and function demonstrates that ATO at 2 µmol L causes enlargement of the mitochondrion, enhancement of mitochondrial membrane potential, and adenosine triphosphate (ATP) production in PCAECs but not in PCASMCs. Thus, both in vivo and in vitro studies demonstrate that AES is an effective strategy for rapid re-endothelialization and inhibition of ISR.
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http://dx.doi.org/10.1002/adhm.201800207DOI Listing
August 2018

Colorimetric theophylline aggregation assay using an RNA aptamer and non-crosslinking gold nanoparticles.

Mikrochim Acta 2017 12 7;185(1):33. Epub 2017 Dec 7.

CAS Key Lab of Bio-Medical Diagnostics, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, 215163, People's Republic of China.

The authors are presenting a rapid method for the determination of theophylline using unique non-crosslinking gold nanoparticle (AuNP) aggregation. An RNA aptamer against theophylline is firstly split into two RNA fragments which then interact with bare AuNPs. The two RNA probes cause an enhancement of the salt tolerance of AuNPs. However, in the presence of theophylline, the RNA probes form a complex with theophylline so that less RNA probes are available to protect the AuNPs from salt-induced aggregation. Theophylline induced aggregation of AuNPs is accompanied by a color change from red to blue. The color change can be detected visually and via UV-vis absorptiometry by ratioing the absorbances at 650 and 520 nm. The ratio increases linearly in the 0.1 to 20 μM theophylline concentration range, with a 67 nM limit of detection. The method is highly sensitive and selective. Graphical abstract Single-stranded split RNA aptamers (R1 and R2) protect gold nanoparticles (AuNPs) from salt-induced non-crosslinking aggregation. After recognition of theophylline by the RNA probe, the unprotected AuNPs aggregate and undergo a color change from red to blue, and this is used to quantify the theophylline concentration.
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http://dx.doi.org/10.1007/s00604-017-2606-4DOI Listing
December 2017

Licochalcone D induces apoptosis and inhibits migration and invasion in human melanoma A375 cells.

Oncol Rep 2018 May 20;39(5):2160-2170. Epub 2018 Mar 20.

School of Integrated Traditional Chinese and Western Medicine, Binzhou Medical University, Yantai, Shandong 264000, P.R. China.

The aim of the present study was to determine the effects of Licochalcone D (LD) on the apoptosis and migration and invasion in human melanoma A375 cells. Cell proliferation was determined by sulforhodamine B assay. Apoptosis was assessed by Hoechst 33258 and Annexin V‑FITC/PI staining and JC‑1 assay. Total intracellular reactive oxygen species (ROS) was examined by DCFH‑DA. Wound healing and Transwell assays were used to detect migration and invasion of the cells. The activities of matrix metalloproteinase (MMP‑2 and MMP‑9) were assessed via gelatin zymography. Tumor growth in vivo was evaluated in C57BL/6 mice. RT‑PCR, qPCR, ELISA and western blot analysis were utilized to measure the mRNA and protein levels. Our results showed that LD inhibited the proliferation of A375 and SK‑MEL‑5 cells in a concentration‑dependent manner. After treatment with LD, A375 cells displayed obvious apoptotic characteristics, and the number of apoptotic cells was significantly increased. Pro‑apoptotic protein Bax, caspase‑9 and caspase‑3 were upregulated, while anti‑apoptotic protein Bcl‑2 was downregulated in the LD‑treated cells. Meanwhile, LD induced the loss of mitochondrial membrane potential (ΔΨm) and increased the level of ROS. ROS production was inhibited by the co‑treatment of LD and free radical scavenger N‑acetyl‑cysteine (NAC). Furthermore, LD also blocked A375 cell migration and invasion in vitro which was associated with the downregulation of MMP‑9 and MMP‑2. Finally, intragastric administration of LD suppressed tumor growth in the mouse xenograft model of murine melanoma B16F0 cells. These results suggest that LD may be a potential drug for human melanoma treatment by inhibiting proliferation, inducing apoptosis via the mitochondrial pathway and blocking cell migration and invasion.
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http://dx.doi.org/10.3892/or.2018.6329DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5928765PMC
May 2018

Electrochemical Determination of Ca Based On Recycling Formation of Highly Selective DNAzyme and Gold Nanoparticle-Mediated Amplification.

Bioconjug Chem 2018 04 12;29(4):1021-1024. Epub 2018 Mar 12.

Suzhou Institute of Biomedical Engineering and Technology , Chinese Academy of Sciences , Suzhou 215163 , People's Republic of China.

Calcium ion (Ca) plays a critical and indispensable role in many physiological and biochemical processes in the human body. In this report, we demonstrate a novel electrochemical method for the determination of the Ca level aided by three functional DNA probes and gold nanoparticles (AuNPs). It affords high selectivity in sensing Ca over other metal cations, which is due to the adoption of the DNAzyme at the electrode interface with exceptionally high binding ability. This method also integrates recycling formation of DNAzyme and AuNPs-mediated amplification; thus, high sensitivity is promised. Therefore, this work provides a favorable way to probe Ca for biomedical applications.
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http://dx.doi.org/10.1021/acs.bioconjchem.8b00096DOI Listing
April 2018

Coupling loss characteristics of runoff-sediment-adsorbed and dissolved nitrogen and phosphorus on bare loess slope.

Environ Sci Pollut Res Int 2018 May 7;25(14):14018-14031. Epub 2018 Mar 7.

Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Ministry of Education, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China.

Soil and nutrient loss is a common natural phenomenon but it exhibits unclear understanding especially on bare loess soil with variable rainfall intensity and slope gradient, which makes it difficult to design control measures for agricultural diffuse pollution. We employ 30 artificial simulated rainfalls (six rainfall intensities and five slope gradients) to quantify the coupling loss correlation of runoff-sediment-adsorbed and dissolved nitrogen and phosphorus on bare loess slope. Here, we show that effects of rainfall intensity on runoff yield was stronger than slope gradient with prolongation of rainfall duration, and the effect of slope gradient on runoff yield reduced gradually with increased rainfall intensity. But the magnitude of initial sediment yield increased significantly from an average value of 6.98 g at 5° to 36.08 g at 25° with increased slope gradient. The main factor of sediment yield would be changed alternately with the dual increase of slope gradient and rainfall intensity. Dissolved total nitrogen (TN) and dissolved total phosphorus (TP) concentrations both showed significant fluctuations with rainfall intensity and slope gradient, and dissolved TP concentration was far less than dissolved TN. Under the double influences of rainfall intensity and slope gradient, adsorbed TN concentration accounted for 7-82% of TN loss concentration with an average of 58.6% which was the main loss form of soil nitrogen, adsorbed TP concentration accounted for 91.8-98.7% of TP loss concentration with an average of 96.6% which was also the predominant loss pathway of soil phosphorus. Nitrate nitrogen (NO-N) accounted for 14.59-73.92% of dissolved TN loss, and ammonia nitrogen (NH-N) accounted for 1.48-18.03%. NO-N was the main loss pattern of TN in runoff. Correlation between dissolved TN, runoff yield, and rainfall intensity was obvious, and a significant correlation was also found between adsorbed TP, sediment yield, and slope gradient. Our results provide the underlying insights needed to guide the control of nitrogen and phosphorus loss on loess hills.
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http://dx.doi.org/10.1007/s11356-018-1619-9DOI Listing
May 2018
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