Jun Li
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Publication
Journal: Frontiers in plant science
November/21/2019
Abstract
Plant cyclic peptides (CPs) are a large group of small molecule metabolites found in a wide variety of plants, including traditional Chinese medicinal plants. However, the majority of plant CPs have not been studied for their biosynthetic mechanisms, including heterophyllin B (HB), which is one of the characteristic chemical components of Pseudostellaria heterophylla. Here, we screened the precursor gene (prePhHB) of HB in P. heterophylla and functionally identified its correctness in vivo and in vitro. First, we developed a new method to screen the precursors of HB from 16 candidate linear peptides. According to transcriptome sequencing data, we cloned the genes that encoded the HB precursor peptides and confirmed that the prePhHB-encoded precursor peptide could enzymatically synthesize HB. Next, we generated the transgenic tobacco that expressed prePhHB, and the results showed that HB was detected in transgenic tobacco. Moreover, we revealed that prePhHB gene expression is positively correlated with HB accumulation in P. heterophylla. Mutations in the prePhHB gene may influence the accumulation of HB in P. heterophylla. These results suggest that HB is ribosomally synthesized and posttranslationally modified peptide (RiPP) derived from the precursor gene prePhHB-encoded precursor peptide, and the core peptide sequence of HB is IFGGLPPP in P. heterophylla. This study developed a new idea for the rapid identification of Caryophyllaceae-type CP precursor peptides via RNA-sequencing data mining.
Publication
Journal: Turkish journal of medical sciences
October/27/2019
Abstract
Hypertension is an important risk factor for cognitive impairment. This study explored whether elderly patients with stage I hypertension (HPs) and normotensive patients (NPs) showed differences in the recovery of postoperative attention network function, according to attentional network test (ANT) performance.Of 110 patients screened, 25 HPs and 25 NPs completed this study. All participants completed the Mini-Mental State Examination 1 day preoperatively and the ANT on postoperative days (PODs) 2 and 7.Compared with NPs, HPs had significantly lower alerting network effect scores and more difficulty resolving conflict on POD 7. However, no significant difference was observed between groups on POD 2. Orienting network performance was similar between groups at all timepoints. Significant differences in alerting and executive control network performance were observed between PODs 2 and 7 within each group.HPs showed selective cognitive impairment at different timepoints following elective hip or knee arthroplasty. Compared with NPs, HPs were more likely to experience delayed recovery of alerting and executive control network function, but not orienting network function, during the first postoperative week.
Publication
Journal: Molecular imaging and biology
October/25/2019
Abstract

PURPOSE
Diabetic retinopathy (DR) is characterized by dopaminergic neuron loss in the retina of the eyes. [18F]fluoropropyl-(+)-dihydrotetrabenazine ([18F]FP-(+)-DTBZ) positron emission tomography (PET) has been shown to detect dopaminergic neuron loss. The study is to investigate the feasibility of PET imaging with [18F]FP-(+)-DTBZ for early diagnosis of diabetic retinopathy (DR) in diabetes mellitus (DM) rat models.

METHODS
The DM rat model was established by a single intraperitoneal injection of streptozotocin (STZ) (65 mg/kg). After 4 weeks, 8 weeks, and 12 weeks of STZ injection, the retinas of the rats were evaluated by electroretinogram (ERG), color fundus photography (CFP), fundus fluorescein angiography (FFA), and small animal PET scan with [18F]FP-(+)-DTBZ by targeting vesicular monoamine transporter 2 (VMAT2). [18F]FP-(+)-DTBZ uptake in retina was quantified as standardized uptake value (SUV). Immunofluorescence staining and Western blot were also performed to confirm the expression level of VMAT2 in retina.

RESULTS
ERG dysfunction was observed at 8 weeks in STZ-diabetic rats, evidenced by smaller amplitudes of oscillatory potentials (OPs) when compared with OPs in normal rats. CFP and FFA showed no significant difference in vascular leakage and neovascularization between STZ-diabetic retinas and normal ones until 8 weeks. PET imaging revealed that the SUV of [18F]FP-(+)-DTBZ was significantly lower in the STZ-diabetic retinas compared with the normal ones as early as of week 4. The results from immunofluorescence staining and Western blots confirmed the early findings in PET imaging studies.

CONCLUSIONS
Early DR can be non-invasively detected with PET imaging using [18F]FP-(+)-DTBZ targeting VMAT2. The expression level of VMAT2 in retina may act as a new biomarker for early DR diagnosis.

Publication
Journal: Experimental eye research
June/3/2019
Abstract
Posterior capsule opacification (PCO) is a common long-term complication of modern cataract surgery. The epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs) is a crucial process in the development of PCO. The purpose of this study is to investigate the role of microRNA-34a (miR-34a) in the regulation of EMT and its target gene. Human LECs were treated with TGFβ2 to induce EMT as a model for PCO. The mRNA levels of miR-34a and EMT markers were examined by real-time quantitative polymerase chain reaction (qPCR). The expression level of miR-34a was downregulated, whereas that of Notch1 was upregulated in TGFβ2-induced EMT of LECs. Overexpression of miR-34a by transfection with miR-34a inhibited EMT of LECs and reduced the expression of Notch1; while, inhibition of miR-34a upregulated the expression of both Notch1 and its ligand Jagged1 in LECs. Luciferase reporter assays revealed that Notch1 gene was direct target of miR-34a. Moreover, DAPT, a specific inhibitor of Notch signaling pathway, reversed LEC-EMT. In addition, the expression level of miR-34a was downregulated, whereas that of Notch1 was upregulated in capsular opacification from cataract samples. MiR-34a can negatively regulate EMT of LECs by targeting Notch1. Therefore, miR-34a/Notch1 could serve as a potential therapeutic approach for the treatment of PCO.
Publication
Journal: Journal of cellular biochemistry
May/19/2019
Abstract
As a common phenotype in chronic kidney disease, renal interstitial fibrosis has been largely studied. Norcantharidin (NCTD), a derivative of naturally occurring cantharidin, has an anti-renal fibrotic effect. However, its underlying mechanisms of the protective role remain largely unknown. Long noncoding RNAs (lncRNAs) play vital parts in tissue homeostasis modulation under pathophysiological conditions. In this study, we discovered the underlying lncRNAs and genes, which may contribute to the anti-renal fibrotic effects of NCTD.RNA-seq analysis was performed to evaluate profiling of lncRNAs and messenger RNAs (mRNAs) in kidney tissues of sham-control, and unilateral ureteral obstruction (UUO) mouse models with or without NCTD treatment. Systematic bioinformatic analysis of expression levels was used in lncRNAs and mRNAs of NCTD-treated UUO kidneys. Altered expression of lncRNAs and mRNAs levels was confirmed by quantitative real-time polymerase chain reaction analysis.467 lncRNAs and 1502 mRNAs were differentially expressed between UUO- and sham-operated kidneys, and notably, these alterations in UUO-operated kidney were partially reversed following NCTD treatment. Interestingly, the up-regulation of lncRNA Gm16076, Gm26669, and down-regulation of Fam120aos were highly correlated with the up-regulation of mRNA levels of fibrosis-related gene ITGB1, STAT3 and reduction of Pink1 in UUO kidney, respectively.The result suggested lncRNAs-regulated genes may contribute to the anti-renal fibrotic effect under NCTD treatment, and thus targeting lncRNAs-controlled genes and their related molecular signaling pathways may serve as a promising therapeutic target in renal fibrosis treatment.
Publication
Journal: Journal of the American Chemical Society
May/9/2019
Abstract
The electrochemical reduction of CO2 has seen many record-setting advances in C2 productivity in recent years. However, the selectivity for ethanol, a globally significant commodity chemical, is still low compared to the selectivity for products such as ethylene. Here we introduce diverse binding sites to a Cu catalyst, an approach that destabilizes the ethylene reaction intermediates and thereby promotes ethanol production. We develop a bimetallic Ag/Cu catalyst that implements the proposed design toward an improved ethanol catalyst. It achieves a record Faradaic efficiency of 41% toward ethanol at 250 mA/cm2 and -0.67 V vs RHE, leading to a cathodic-side (half-cell) energy efficiency of 24.7%. The new catalysts exhibit an in situ Raman spectrum, in the region associated with CO stretching, that is much broader than that of pure Cu controls, a finding we account for via the diversity of binding configurations. This physical picture, involving multisite binding, accounts for the enhanced ethanol production for bimetallic catalysts, and presents a framework to design multimetallic catalysts to control reaction paths in CO2 reductions toward desired products.
Publication
Journal: Biochemical and biophysical research communications
April/21/2019
Abstract
The development of adipose tissue is a precisely coordinated cellular process, in which both protein-coding and non-coding genes are involved. To characterize the in vivo function of a novel long non-coding RNA (lncRNAs), loss-of-function assays were performed with slincRAD knockdown mice. Down-regulation of slincRAD expression was found to impair the development of adipose tissue, leading to a slim phenotype for both of the male and female mice. Compared to normal adipocytes, slincRAD knockdown cells had defective differentiation features, such as smaller sizes and decreased lipid production. For elder mice, slincRAD knockdown led to abnormal glucose and lipid metabolism. Therefore, a physiologically important lncRNA was characterized in the development of adipose tissue.
Publication
Journal: Fish & shellfish immunology
January/1/2019
Abstract
Land-based recirculating aquaculture systems (RAS) are widely utilized for turbot (Scophthalmus maximus) culture. Flow velocity in the tank is essential to maintain water quality, conservation of energy and fish welfare. However, little is known about how turbot respond to different velocities in the long term. In this study, water quality was kept constant, allowing the effect of flow velocity on the feeding intake, growth, plasma biochemical indexes, innate (non-specific) immunity and immune-related stress gene expressions in the skin to be examined in isolation in RAS. Turbot (average body length 20.10 cm) were reared for 60 days in RAS under three velocities, 0.06 m s-1, 0.18 m s-1, and 0.36 m s-1, corresponding to approximately 0.3 body length per second (bl s-1), 0.9 bl s-1 and 1.8 bl s-1, respectively. The results showed that at velocities of 0.36 m s-1 (1.8 bl s-1), juvenile turbot were subject to stress accompanied by a reduced growth rate. A velocity of 0.36 m s-1 was also found to significantly reduce SOD and GSH activity, and the concentration of total protein in plasma, while concentrations of urea nitrogen (BUN) and total bilirubin (TBIL) increased. There was an up-regulation of cathepsin D and lysozyme (LZM) in the skin at the highest velocity, implying the activation of stress and immune responses. At the medium velocity of 0.18 m s-1 (0.9 bl s-1), turbot increased their feed intake, obtained an elevated special growth rate (SGR), and exhibited significantly higher AKP and ACP activity in plasma. Overall, the results suggest that excessively high velocities are a stressor for turbot inducing an immune response in the skin, which is sensitive to environmental changes. A velocity of approximately 0.9 bl s-1 is suggested to promote growth and obtain better innate immunity of cultured turbot.
Publication
Journal: Molecular genetics and genomics : MGG
December/6/2018
Abstract
Acne inversa (AI) is a chronic inflammatory disease of hair follicles. The pathogenesis of AI remains unclear. Haploinsufficiency of genes encoding γ-secretase components is the genetic basis for a subset of familial AI. Idiopathic guttate hypomelanosis (IGH) is a leukoderma characterized by multiple porcelain-white macules. Familial AI associated with IGH has not been reported previously. Herein, we present the pathogenic variation in a Chinese Han family with AI and IGH. Peripheral blood samples were collected from 16 members of the entire family. Eighteen exons and flanking introns of the NCSTN gene were amplified by polymerase chain reaction. Two hundred unrelated healthy Chinese subjects were used as controls. Sequencing results were analysed using CodonCode Aligner Software. Seven of the 16 family members in three generations were AI patients. Six AI patients also had IGH, while the other only had AI. One had IGH without AI. All AI patients carried the mutation, c.218delC, located in exon 4 of NCSTN. The deletion mutation led to a reading frame shift and the appearance of a premature termination codon (p.P73Lfs*15), resulting in the production of truncated protein. Family members without AI did not carry this mutation, indicating that it cosegregated with the phenotype. The mutation was not detected among the controls. This mutation has not been reported in the EXaC, HGMD, and dbSNP databases. In addition, we performed whole-exome sequencing on the proband and finally screened six candidate genes, ADAMTS2, BUB1B, CRB2, FBLN1, SEC24B, and WNK1, which we further validated in effected family members, and none of them were cosegregated. In conclusion, we identified a novel deletion mutation in exon 4 of NCSTN, which may underlie the molecular pathogenesis in this AI family. However, we found no relationship between this mutation and IGH.
Publication
Journal: Animal cells and systems
December/6/2018
Abstract
BMP I type receptor inhibitor can selectively inhibit BMP/Smad signaling pathways, mainly by inhibiting the BMP I type receptor activity to prevent phosphorylation of Smad1, Smad5 and Smad9. The aim of the present study was to explore the effects of mouse ovarian granulosa cell function and related gene expression by suppressing BMP/Smad signaling pathway with LDN-193189(A type of BMP I type receptor inhibitor). In this study, we cultivate the original generation of mouse ovarian granular cells then collect cells and cell culture medium after treatment. Cellular localization and expression of Smad9 and P-smad9 proteins was studied by immunofluorescence (IF) in the ovarian granulosa cells of mouse; Related genes mRNA and proteins expression was checked by QRT-PCR and Western blot; Detected the concentration of related hormones by using ELISA kit; finally, the growth of the cells was analyzed by plotting cell growth curve with CCK-8 assay. The results indicate that, suppression of BMP/Smad signaling pathway can inhibit the expression of LHR and FSHR, inhibit cell proliferation and decrease E2 secretion, the mechanism of action maybe reduce the expression of smad9, at the same time, we found that the feedback regulation of smad9 may affect the expression of FSHR and cell proliferation.
Publication
Journal: Molecules (Basel, Switzerland)
December/6/2018
Abstract
This review discusses different forms of nanomaterials generated from chitosan and its derivatives for controlled drug delivery. Nanomaterials are drug carriers with multiple features, including target delivery triggered by environmental, pH, thermal responses, enhanced biocompatibility, and the ability to cross the blood-brain barrier. Chitosan (CS), a natural polysaccharide largely obtained from marine crustaceans, is a promising drug delivery vector for therapeutics and diagnostics, owing to its biocompatibility, biodegradability, low toxicity, and structural variability. This review describes various approaches to obtain novel CS derivatives, including their distinct advantages, as well as different forms of nanomaterials recently developed from CS. The advanced applications of CS-based nanomaterials are presented here in terms of their specific functions. Recent studies have proven that nanotechnology combined with CS and its derivatives could potentially circumvent obstacles in the transport of drugs thereby improving the drug efficacy. CS-based nanomaterials have been shown to be highly effective in targeted drug therapy.
Publication
Journal: Cancer letters
December/3/2018
Abstract
Tumor cells need to attain anoikis resistance to survive prior to metastasis making it a vital trait of malignancy. The molecular mechanism by which hepatocellular carcinoma (HCC) cells resist anoikis remains not fully understood. Here, we report that ZNF32 expression is markedly upregulated in HCC cells upon detachment. Enforced ZNF32 expression significantly promotes the anchorage-independent growth capability of HepG2 and Huh7 cells, whereas knockdown of ZNF32 results in increased apoptosis of HCC cells after detachment. Mechanistically, we demonstrate that ZNF32 overexpression suppresses the reactive oxygen species (ROS) accumulation and maintains mitochondrial membrane potential, leading to ATP, GSH and NADPH elevation and promoting HCC cell survival in response to suspension. Moreover, ZNF32 enhances the phosphorylation and activation of Src/FAK signaling. Src and FAK inhibitors effectively reverse ZNF32-induced anoikis resistance in HCC cells. Collectively, our findings not only reveal a novel and important mechanism by which ZNF32 contributes to anoikis resistance through maintaining redox homeostasis and activating Src/FAK signaling, but also suggest the potential therapeutic value of ZNF32 in HCC patients.
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Publication
Journal: Psychiatric genetics
November/26/2018
Abstract
Catechol-O-methyltransferase (COMT) gene variants may be involved in the pathogenesis of psychotic symptoms, and associated especially with negative symptom in schizophrenia, but their roles in cognitive function and treatment response remain unclear. The aim of this study was to explore the association between COMT gene polymorphisms, clinical symptoms (including cognitive function), and treatment response to antipsychotic medications in patients with schizophrenia.
A total of 200 Han Chinese inpatients with schizophrenia were recruited in accordance with Diagnostic and Statistical Manual of Mental Disorders, 4th ed. (DSM-IV). In total, 96 of them completed assessments at baseline and after 8 weeks of antipsychotic treatment. Clinical symptoms were assessed using the Positive And Negative Syndrome Scale (PANSS), and cognitive function was evaluated using the Verbal Fluency Test, Trail Making Test A-B, Stroop Color-Word Test, and Wisconsin Card Sorting Test. Two single nucleotide polymorphisms, rs4680 and rs165599, on the COMT gene were genotyped.
At baseline, we found no significant genotypic association between rs4680 and clinical symptoms or cognitive function. After 8 weeks of antipsychotic treatment, compared with patients with GG genotype, patients with AA/AG genotypes at rs4680 showed significantly higher scores on PANSS total, both at baseline and at the end of 8 weeks, especially in negative and general psychopathology symptoms. Patients with GG at rs165599 scored significantly higher on the Stroop test, suggesting better cognitive performance after 8 weeks of treatment. No significant association was found between rs165599 genotype and psychiatric symptoms as assessed by the PANSS and cognitive function tests at baseline.
Our findings suggest that the COMT gene polymorphisms may influence the response to antipsychotic treatment in Han Chinese patients with schizophrenia.
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Publication
Journal: Journal of natural products
November/25/2018
Abstract
Fifteen new structurally unique monoterpenoid carbazole alkaloids, including two pairs of epimers (1/2 and 3/4), three pairs of enantiomers (6a/6b, 7a/7b, and 8a/8b), and five optically pure analogues (5, 9-12), were obtained from a 95% aqueous EtOH extract of Murraya microphylla by a combination of bioassay- and LC-MS-guided fractionation procedures. Their structures were established based on NMR and HRESIMS data interpretation. The absolute configuration of compound 1 was determined via X-ray crystallographic data analysis and for all compounds by comparison of experimental and calculated ECD data. Compounds 1-5 were assigned as five new thujane-carbazole alkaloids, and compounds 6-12 as 10 new menthene-carbazole alkaloids linked through an ether or carbon-carbon bond. Compounds 1-12 promoted insulin secretion in the HIT-T15 cell line, 1.9-3.1-fold higher than the gliclazide control at 100 μM.
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Publication
Journal: Journal of molecular histology
November/22/2018
Abstract
Cdkn1c, a member of the Cip/Kip cyclin-dependent kinase inhibitor family, is critically involved in regulating cell cycle and cellular differentiation during development in mammals. However, the functional role of Cdkn1c and the underlying mechanisms by which Cdkn1c affects odontogenesis remain largely unknown. In our study, we found that Cdkn1c expression dynamically changes from embryonic day 11.5 (E11.5) to postnatal day 3 (P3), and exhibits tissue-specific expression profiles. Evaluation of CDKN1C protein by immunohistochemistry and western blot, revealed that CDKN1C protein expression peaks at P3 and then is reduced at P5 and P7. Interestingly, we observed that CDKN1C expression is higher in immature odontoblasts than preodontoblasts, is lower in mature odontoblasts, and is practically absent from ameloblasts. We evaluated cell cycle progression to further investigate the mechanisms underlying CDKN1C-mediated regulation of odontogenesis, and found that pRB, cyclin D1 and CDK2 expression decreased from P1 to P3, and reduced at P5 and P7. In addition, we observed increased methylation of KvDMR1 at P1 and P3, and reduced KvDMR1 methylation at P5 and P7. However, the methylation levels of Cdkn1c-sDMR were relatively low from P1 to P7. In summary, we demonstrated that Cdkn1c expression and methylation status may be involved in early postnatal tooth development through regulating the cell cycle inhibition activity of Cdkn1c. Notably, Cdkn1c expression and methylation may associate with cell cycle exit and differentiation of odontoblasts.
Publication
Journal: Analytical chemistry
November/19/2018
Abstract
Adenosine triphosphate (ATP) as a primary energy source plays a unique role in the regulation of all cellular events. The necessity to detect ATP requires sensitive and accurate quantitative analytical strategies. Herein, we present our study of developing a MoS2 nanosheet-enhanced aptasensor for fluorescence polarization-based ATP detection. A bifunctional DNA strand was designed to consist of chimeric aptamers that recognize and capture ATP and berberine, a fluorescence enhancer. In the absence of ATP, the DNA strand bound to berberine will be hydrolyzed when Exonuclease I (Exo I) is introduced, releasing berberine as a result. In contrast, when ATP is present, ATP aptamer folds into a G-quadruplex structure; thus, the complex can resist degradation by Exo I to maintain berberine for fluorescent detection purpose. In addition, to magnify the fluorescence polarization (FP) signal, MoS2 nanosheets were also adopted in the system. This nanosheets-enhanced FP strategy is simple and facile which does not require traditional dye-labeled DNA strands and complex operation steps. The developed fluorescence polarization aptasensor showed high sensitivity for the quantification of ATP with a detection limit of 34.4 nM, performing well both in buffer solution and in biological samples.
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Publication
Journal: Nature communications
November/19/2018
Abstract
The current industrial ammonia synthesis relies on Haber-Bosch process that is initiated by the dissociative mechanism, in which the adsorbed N2 dissociates directly, and thus is limited by Brønsted-Evans-Polanyi (BEP) relation. Here we propose a new strategy that an anchored Fe3 cluster on the θ-Al2O3(010) surface as a heterogeneous catalyst for ammonia synthesis from first-principles theoretical study and microkinetic analysis. We have studied the whole catalytic mechanism for conversion of N2 to NH3 on Fe3/θ-Al2O3(010), and find that an associative mechanism, in which the adsorbed N2 is first hydrogenated to NNH, dominates over the dissociative mechanism, which we attribute to the large spin polarization, low oxidation state of iron, and multi-step redox capability of Fe3 cluster. The associative mechanism liberates the turnover frequency (TOF) for ammonia production from the limitation due to the BEP relation, and the calculated TOF on Fe3/θ-Al2O3(010) is comparable to Ru B5 site.
Publication
Journal: Ying yong sheng tai xue bao = The journal of applied ecology
November/8/2018
Abstract
Soil fertility properties described by four physical indices and seven chemical indices in the 10-year long-term experiment of wheat fields in Weibei Highland were used to investigate the cumulative effect of 11 soil indices under six long-term conservation tillage treatments. The principal component analysis was performed to comprehensively evaluate the cumulative effect of soil fertility under different tillage treatments, so as to provide scientific basis for soil sustainable utilization and management in Weibei Highland. The results showed that, compared with continuous conventional tillage (CT/CT), soil bulk density by no-tillage/subsoiling rotational tillage (NT/ST), subsoiling/conventional tillage rotational tillage (ST/CT) and conventional tillage/no-tillage rotational tillage (CT/NT) decreased by 6.6%, 5.9% and 6.6%, respectively, and no significant difference was found between continuous no-tillage (NT/NT) and CT/CT. NT/NT had the highest content of >0.25 mm mechanical stable aggregate, and no-tillage/subsoiling rotational tillage (NT/ST) had the highest content of >0.25 mm water stable aggregate. Compared with CT/CT, the mechanical stable aggregate contents under other five tillage treatments increased by 1.7%-10.1%, soil organic matter increased by 0.6%-11.2%, and the contents of nitrogen, phosphorus, and potassium contents also increased. By principal component analysis, 11 soil indices were divided into two principal components to comprehensively characterize soil quality. The contribution rate of the first principal component was 75.5%, where the major contributors were soil organic matter, water stable aggregate, total nitrogen, total phosphorus, total potassium, alkaline hydrolysis nitrogen, available phosphorus, available potassium, bulk density and soil porosity. The contribution rate of the second principal component was 13.2%, where the major contributor was mechanical stable aggregate. Together, those two principal components accounted for 88.6% of the original variables. The soil fertility performance was in the sequence of NT/ST>ST/CT>CT/NT>NT/NT>ST/ST>CT/CT after gradually accumulating the effects of long-term conservation tillage. NT/ST was the most appropriate tillage patterns for the wheat fields in Weibei Highland, due to the resulting balanced and high-quality soil environment.
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Publication
Journal: Analytical chemistry
October/1/2018
Abstract
A T790M secondary mutation in epidermal-growth-factor receptor (EGFR) is the most well-established EGFR-tyrosine-kinase-inhibitor (TKI) resistance marker in non-small-cell lung cancer (NSCLC). The current methods to rapidly and accurately detect T790M in clinical practice are not satisfactory because of several obstacles, including the unavailability of tumor-tissue rebiopsies and the low DNA copy number of T790M in circulating tumor DNA (ctDNA). Here, we develop library-aliquot-based droplet digital PCR (LAB-ddPCR) to increase detection sensitivity without affecting accuracy. This new LAB-ddPCR method is performed using aliquots of the ctDNA precapture next-generation-sequencing (NGS) library, in which the isolated ctDNA was amplified and enriched. We show that the LAB-ddPCR can precisely distinguish between T790M wild-type and mutation alleles without introducing extra false-positive signals. In a cohort of 70 post-TKI NSCLC patients, the LAB-ddPCR identified 41 T790M-positive cases (sensitivity 58.57%), but ddPCR only detected T790M in 27 cases (sensitivity 38.57%). Taking the ARMS-PCR result from matched tumor rebiopsies into consideration, the LAB-ddPCR method is better than ddPCR. In conclusion, the LAB-ddPCR ctDNA test offers a feasible and flexible option for the rapid and accurate detection of the T790M secondary mutation, which is helpful in dynamically monitoring drug response and disease progression throughout the therapeutic regimen.
Publication
Journal: Insect biochemistry and molecular biology
September/8/2018
Abstract
Like pathogens, galling insects deliver effectors into plant tissues that induce gall formation. The gall midge Mayetiola destructor, also called Hessian fly, can convert a whole wheat seedling into a gall by inducing the formation of nutritive cells at the feeding site, inhibiting wheat growth, and reprogramming metabolic pathways of the attacked plants. Here we demonstrated the identification of a secreted Hessian fly protein, the nucleoside diphosphate kinase (NDK), in infested wheat plants through liquid chromatography-tandem mass spectrometry (LC-MS/MS) and western blots. In association with the NDK presence, enzymatic activity of NDK increased significantly in wheat tissues at the feeding site. In addition, there was a sudden increase in ATP abundance at the feeding site of infested susceptible wheat seedlings 24 h following Hessian fly larval infestation. Even though a direct link between cause and effect remains to be established, our data points to the direction that Hessian fly larvae injected NDK into wheat tissues as an effector protein, which plays a role in manipulating host plants and converting the plants into galls.
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Journal: Shanghai kou qiang yi xue = Shanghai journal of stomatology
August/26/2018
Abstract
OBJECTIVE
To analyze the accuracy of 3D reconstruction of pulp cavity in mandibular premolars based on cone-beam CT (CBCT).
METHODS
Thirty-two extracted single-rooted mandibular premolars were randomly collected and scanned by micro-CT and CBCT. After image segmentation and 3D reconstruction, the surface model and volume model of the pulp cavity were rendered. By using Amira 5.0 software, each pairs of pulp cavity surface models were registered. The surface models reconstructed from micro-CT scanning were set as the references and the surface models reconstructed from CBCT were tested. The morphological differences between each pairs of surface models were calculated by Amira 5.0 software and represented by color-coded maps. The total 3D morphological difference value of each sample was recorded and the volume reconstruction differences between the two image acquisition techniques were analyzed. Statistical analysis was performed with SPSS 13.0 software package.
RESULTS
The mean value of 3D morphological differences of 32 teeth was 0.27 mm. Distribution of the greatest morphological differences were mainly located in the apical portion of the pulp cavity and some small anatomical variation. The volume of the reconstructed models by micro-CT and CBCT were (34.89±4.36) mm3 and (27.32±4.83) mm3 respectively, and the difference was significant (P<0.05).
CONCLUSIONS
When CBCT scanning is used to reconstruct pulp cavity of mandibular premolars, there is certain degree of information loss, which mainly distributes in the apical portion and small anatomical variation sites. Dentists should consider these characteristics during clinical application of CBCT.
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Journal: Huan jing ke xue= Huanjing kexue
July/1/2018
Abstract
This study investigates the effect of increased hydraulic retention time (HRT) and dissolved oxygen (DO) on the destruction and restoration of the performance of activated sludge and biofilm sequencing batch reactor (SBR) nitritation after the processes were simultaneously started up and stably operated at room temperature (25℃). The results showed that was easier to start nitritation in an activated sludge reactor, but nitritation was destroyed when DO was 2-2.5 mg·L-1. The performance could be restored by reducing DO to 0.5-1 mg·L-1. The biofilm process was not affected by DO. Prolonging HRT destroyed the stable operation of the two processes. Compared with the method of biofilm, the activated sludge method had less resistance, but restoring performance was better than for the biofilm process after shortening the HRT. Subsequently, the temperature (20, 15, and 10℃) was continuously reduced to investigate the synergistic effect of DO and temperature on nitritation stabilization. The results showed that the reduction of temperature destroyed the stable operation of nitritation, but the reduction of DO concentration could compensate for the adverse effects of temperature reduction. In addition, when the temperature was higher than 20℃, the rate of nitritation in the activated sludge process was better than that in thebiofilm method. At low temperature (below 15℃), a stable operation of nitritation was easier to achieve with the biofilm method. The capacity of the activated sludge process was hardly changed at 10℃. The above conclusions were confirmed by molecular microbiological analysis, and it was found that the stable operation of nitritation could be achieved without complete wash-out of the nitrite-oxidizing bacteria (NOB).
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Journal: Colloids and surfaces. B, Biointerfaces
June/4/2018
Abstract
The tumor suppressor protein p53 plays a central role in preventing cancer through interaction with DNA response elements (REs) to regulate target gene expression in cells. Due to its significance in cancer biology, relentless efforts have been directed toward understanding p53-DNA interactions for the development of cancer therapeutics and diagnostics. In this paper, we report a rapid, label-free and versatile colorimetric assay to detect wildtype p53 DNA-binding function in complex solutions. The assay design is based on a concept that alters interparticle-distances between RE-AuNPs from a crosslinking effect induced through tetramerization of wildtype p53 protein (p53-WT) upon binding to canonical DNA motifs modified on gold nanoparticles (RE-AuNPs). This leads to a visible solution color change from red to blue, which is quantifiable by the UV- visible absorption spectra with a detection limit of 5 nM. Contrastingly, no color change was observed for the binding-deficient p53 mutants and non-specific proteins due to their inability to crosslink RE-AuNPs. Based on this sensing principle, we further demonstrate its utility for fast detection of drug-induced DNA binding function to cancer-associated Y220C mutant p53 protein using well-established reactivating compounds. By exploiting the dominant-negative property of mutant p53 over p53-WT and interactions with RE-AuNPs, this assay is configurable to detect low numbers of mutant p53 expressing cells in miniscule sample fractions obtained from typical core needle biopsy-sized tissues without signal attrition, alluding to the potential for biopsy sampling in cancer diagnostics or for defining cancer margins. This nanogold enabled colorimetric assay provides a facile yet robust method for studying important parameters influencing p53-DNA interactions with great promises for clinically pertinent applications.
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Journal: Journal of hepatology
May/18/2018
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