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1.
Biosci Rep ; 2020 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-32426838

RESUMO

LncRNA LINC00657 has oncogenic or anti-carcinoma roles in different cancers, and yet its detailed molecular mechanism in esophageal cancer(EC) remains unclear. In addition, competitive endogenous RNA (ceRNA) regulatory lncRNA-miRNA-mRNA networks are critical for tumorigenesis and progression. Hence, this study explored the roles of LINC00657 in EC and identified its relevant ceRNA network. We firstly detected the expression of LINC00657 in EC. Then, we applied starBase and TargetScan websites to find miR-26a-5p binding to LINC00657 and obtain CKS2 as a target of miR-26a-5p. The roles of LINC00657, miR-26a-5p or CKS2 in the proliferation, migration, invasion and apoptosis of EC cells were respectively assessed by CCK-8, wound healing assay, transwell invasion assay, and flow cytometry. The changes of the MDM2/p53/Bcl2/Bax pathway were measured via western blot. The results revealed that LINC00657 showed an aberrant high expression in EC cells, which promoted the growth of EC cells. Additionally, LINC00657 functioned as a sponge of miR-26a-5p, and LINC00657 negatively mediated miR-26a-5p to regulate the growth of EC cells. Furthermore, CKS2 was observed as a direct target of miR-26a-5p, and CKS2 controlled the growth of EC cells via the MDM2/p53/Bcl2/Bax pathway. Moreover, there was a positive correlation between LINC00657 and CKS2. LINC00657 knockdown inhibited CKS2 expression to suppress the proliferation, migration and invasion of EC cells and induced apoptosis via regulating the MDM2/p53/Bcl2/Bax pathway. Collectively, LINC00657/miR-26a-5p/CKS2 ceRNA network could promote the progression of EC, which is good for understanding the molecular mechanism of EC and offers novel biomarkers for EC diagnosis and therapy.

2.
J Mol Diagn ; 22(5): 708-719, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32359725

RESUMO

Salmonella is a common cause of foodborne disease worldwide, including Australia. More than 85% of outbreaks of human salmonellosis in Australia were caused by five Salmonella serovars. Rapid, accurate, and sensitive identification of Salmonella serovars is vital for diagnosis and public health surveillance. Recently, an isothermal amplification technique, termed multiple cross-displacement amplification (MCDA), has been employed to detect Salmonella at the species level. Herein, seven MCDA assays were developed and evaluated for rapid detection and differentiation of the five most common Salmonella serovars in Australia: Typhimurium, Enteritidis, Virchow, Saintpaul, and Infantis. MCDA primer sets were designed by targeting seven serovar/lineage-specific gene markers identified through genomic comparisons. The sensitivity and specificity of the seven MCDA assays were evaluated using 79 target strains and 32 nontarget strains. The assays were all highly sensitive and specific to target serovars, with the sensitivity ranging from 92.9% to 100% and the specificity from 93.3% to 100%. The limit of detection of the seven MCDA assays was 50 fg per reaction (10 copies) from pure DNA, and positive results were detected in as little as 8 minutes. These seven MCDA assays offer a rapid, accurate, and sensitive serotyping method. With further validation in clinically relevant conditions, these assays could be used for culture-independent serotyping of common Salmonella serovars directly from clinical samples.

3.
Artigo em Inglês | MEDLINE | ID: mdl-32370730

RESUMO

BACKGROUND: Gastrointestinal symptoms are often the first symptoms of hypopituitarism. However, pseudo-intestinal obstruction is not a common manifestation of hypopituitarism. Some patients presenting with gastrointestinal symptoms as their chief complaint were admitted to the Department of Gastroenterology and were accurately diagnosed with hypopituitarism at the Department of Endocrinology. CASE SUMMARY: This case pertains to a 57-year-old man with poor appetite, fatigue, weakness, and recent onset recurring abdominal pain. An erect, abdominal X-ray indicated flatulence and gas-fluid levels in the midsection of the abdomen, and pseudo-intestinal obstruction was diagnosed. Subsequently, the patient was referred to the Department of Gastroenterology to identify the cause of the pseudo-intestinal obstruction. An examination of the digestive system did not reveal any abnormalities, but the patient developed hyponatremia and exhibited drowsiness. The patient was transferred to the Department of Endocrinology for further treatment. The patient was eventually diagnosed with hypopituitarism, caused by empty sella syndrome. The patient received prednisone and euthyrox replacement therapy, and pseudo-intestinal obstruction did not occur again. CONCLUSION: In general, endocrine diseases, including hypopituitarism, hypothyroidism, and hyponatremia, should be considered for patients with pseudo-intestinal obstruction combined with hyponatremia and drowsiness, especially if the symptoms of the digestive system are not complicated and the drowsiness is obvious.

4.
Diabetes Obes Metab ; 2020 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-32267071

RESUMO

BACKGROUND: Chinese guidelines for the treatment of type 2 diabetes (T2D) recommend basal or premixed insulins as insulin starters after failed oral antihyperglycaemic medication (OAM). This pragmatic study compared effectiveness and safety of add-on basal insulin analog (BI) and mid-mixture insulin analog (MMI; 50:50 premixed insulin) as starter insulin regimens in Chinese patients with T2D in a real-world setting. MATERIALS AND METHODS: This was a multicentre, open-label, randomized, parallel, pragmatic trial. Patients receiving OAMs were randomized 1:1 to BI (n = 410) or MMI (n = 404) for 24 weeks. Insulin titration and OAM adjustment were determined by investigators following usual standard-of-care. The primary outcome was change in glycated haemoglobin (HbA1c) from baseline. RESULTS: Least-squares mean changes in HbA1c from baseline to week 24 were -2.00% and -2.15% for BI and MMI groups, respectively (P = .13). The MMI group demonstrated a greater reduction in concomitant OAM therapies used than BI group (53.8% vs. 35.3%, respectively; P < .001). Very limited daily insulin dose increments were observed from baseline to week 24 in both BI and MMI groups (2.5 U/day and 1.8 U/day, respectively). Although both insulin analogs were well-tolerated without severe hypoglycaemia, small weight gains were seen with both treatments. Higher total hypoglycaemia rates were noticed with the MMI group, while nocturnal hypoglycaemia events were comparable. CONCLUSIONS: In real-world settings, BI and MMI provided similar improvement in glucose control without conceding hypoglycaemia. The BI group received a greater number of OAMs in real-world settings. Limited insulin dose titration was observed, while more adjustments occurred with OAM usage.

5.
Biosci Rep ; 40(4)2020 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-32323724

RESUMO

The association between lung and intestine has already been reported, but the differences in community structures or functions between lung and intestine bacteria yet need to explore. To explore the differences in community structures or functions, the lung tissues and fecal contents in rats were collected and analyzed through 16S rRNA sequencing. It was found that intestine bacteria was more abundant and diverse than lung bacteria. In intestine bacteria, Firmicutes and Bacteroides were identified as major phyla while Lactobacillus was among the most abundant genus. However, in lung the major identified phylum was Proteobacteria and genus Pseudomonas was most prominent genus. On the other hand, in contrast the lung bacteria was more concentrated in cytoskeleton and function in energy production and conversion. While, intestine bacteria were enriched in RNA processing, modification chromatin structure, dynamics and amino acid metabolism. The study provides the basis for understanding the relationships between lung and intestine bacteria.

6.
Artigo em Inglês | MEDLINE | ID: mdl-32336082

RESUMO

Recently, several types of lead halide perovskites have been demonstrated as active layers in resistive switching memory or artificial synaptic devices for neuromorphic computing applications. However, the thermal instability and toxicity of lead halide perovskites severely restricted their further practical applications. Herein, the environmentally friendly and uniform Cs3Cu2I5 perovskite films are introduced to act as the active layer in the Ag/Cs3Cu2I5/ITO memristor. Generally, the Ag ions could react with iodide ions and form AgIx compounds easily, so the Ag/PMMA/Cs3Cu2I5/ITO memristor was designed by employing the ultrathin polymethylmethacrylate (PMMA) layer to avoid the direct contact between the top Ag electrode and Cs3Cu2I5 perovskite films. After optimization, the obtained memristor demonstrated bipolar resistive switching with low operating voltage (< ±1 V), large on/off ratio (102), stable endurance (100 cycles), and long retention (>104 s). Additionally, biological synaptic behaviors including long-term potentiation and long-term depression have been investigated. By using the MNIST handwritten recognition data set, the handwritten recognition rate based on experimental data could reach 94%. In conclusion, our work provides the opportunity of exploring the novel application for the development of next-generation neuromorphic computing based on lead-free halide perovskites.

8.
Curr Med Res Opin ; : 1-9, 2020 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-32338063

RESUMO

Objective: DBPR108, a novel dipeptidyl-peptidase-4 inhibitor, has shown great antihyperglycemic effect in animal models. This study was to evaluate the efficacy and safety of DBPR108 monotherapy in type 2 diabetes mellitus (T2DM).Methods: This was a 12-week, double-blind, placebo-controlled phase II clinical trial. The newly diagnosed or inadequately controlled untreated T2DM patients were randomized to receive 50, 100, 200 mg DBPR108 or placebo in a ratio of 1:1:1:1. The primary efficacy outcome was HbA1c change from baseline to week 12. Relevant secondary efficacy parameters and safety were assessed. The clinical trial registration is NCT04124484.Results: Overall, 271 of the 276 randomized patients, who received 50 mg (n = 68), 100 mg (n = 67), 200 mg (n = 69) DBPR108 or placebo (n = 67), were included in full analysis set. At week 12, HbA1c change from baseline was -0.04 ± 0.77 in placebo group, -0.51 ± 0.71, -0.75 ± 0.73, and -0.57 ± 0.78 (%, p < .001 vs. placebo) in 50, 100, and 200 mg DBPR108 groups, respectively. Since week 4, DBPR108 monotherapy resulted in significant improvements in secondary efficacy parameters. At end of 12-week treatment, the goal of HbA1c ≤7% was achieved in 29.85, 58.82, 55.22, and 47.83% of the patients in placebo, 50, 100, and 200 mg DBPR108 groups, respectively. The incidence of adverse events did not show significant difference between DBPR108 and placebo except mild hypoglycemia in DBPR108 200 mg group.Conclusions: The study results support DBPR108 100 mg once daily as the primary dosing regimen for T2DM patients in phase III development program.

9.
Biol Trace Elem Res ; 2020 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-32249377

RESUMO

The assessment method of iodine nutrition for pregnant women lacks strong evidence-based medicine. The prevalence of iodine deficiency in pregnant women may be overestimated using urinary iodine concentration (UIC). The reference intervals of UIC-to-urinary creatinine concentration ratio (UIC/UCr) were established using a self-sequential longitudinal study of pregnant women with singleton gestation who were recruited using the criteria of the National Academy of Clinical Biochemistry in Dandong City, which is a long-term iodine-replete area. Nine thousand one hundred sixty-four pregnant women in the first trimester from Dalian City, Dandong City, and Shenyang City were included to verify our proposed reference intervals. UIC and concentrations of urinary creatinine, serum iodine, TSH, FT4, TPOAb, and TgAb were measured. The reference intervals of UIC/UCr were 38.63-489.46 µg/g for the first trimester, 58.48-644.03 µg/g for the second trimester, and 56.27-644.93 µg/g for the third trimester. The prevalence of iodine deficiency was 49.50% using UIC as the indicator (< 150 µg/L), while the prevalence was 3.28% using UIC/UCr (< 38.63 µg/g). The prevalence of iodine excess was 3.21% using UIC as the indicator (> 500 µg/L) while the prevalence was 1.45% using UIC/UCr (> 489.46 µg/g). The highest prevalence of overt hypothyroidism and positive thyroid antibodies was in the group with UIC/UCr < 38.63 µg/g. In contrast to the place of residence and age, BMI was an influencing factor for UIC/UCr. The reference intervals of UIC/UCr were established. UIC/UCr may eliminate the effect of urine volume and reflect the actual prevalence of iodine deficiency in pregnant women.

10.
Chin Med J (Engl) ; 133(8): 968-974, 2020 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-32187054

RESUMO

Autoimmune diseases are primary immune diseases in which autoreactive antibodies or sensitized lymphocytes destroy and damage tissue and cellular components, resulting in tissue damage and organ dysfunction. Helper T cells may be involved in the pathogenesis of autoimmune diseases under certain conditions. This review summarizes recent research on the role of helper T cells in autoimmune diseases from two aspects, helper T cell-mediated production of autoantibodies by B cells and helper T cell-induced activation of abnormal lymphocytes, and provides ideas for the treatment of autoimmune diseases. The abnormal expression of helper T cells promotes the differentiation of B cells that produce autoantibodies, which leads to the development of different diseases. Among them, abnormal expression of Th2 cells and T follicular helper cells is more likely to cause antibody-mediated autoimmune diseases. In addition, abnormal activation of helper T cells also mediates autoimmune diseases through the production of abnormal cytokines and chemokines. Helper T cells play an essential role in the pathogenesis of autoimmune diseases, and a full understanding of their role in autoimmune diseases is helpful for providing ideas for the treatment of autoimmune diseases.

11.
Sheng Wu Gong Cheng Xue Bao ; 36(2): 295-308, 2020 Feb 25.
Artigo em Chinês | MEDLINE | ID: mdl-32148002

RESUMO

γ-polyglutamic acid (γ-PGA) is widely used in food processing, cosmetic production, medicinal industry, etc. Currently, the production strains used in fermentation process are commonly glutamic acid-dependent, which results in extra cost. In this study, a de novo way of producing γ-PGA from sugars was reported. To this end, the γ-polyglutamate synthase gene cluster pgsBCA was cloned from the natural γ-PGA-producing strain Bacillus subtilis (ATCC 6051-U), and was constitutively and inducibly expressed in Corynebacterium glutamicum ATCC 13032. Only inducible expression of pgsBCA can lead to the generation of γ-PGA with a titer of 1.43 g/L from glucose, without any supplementation of glutamic acid. The production was further elevated to 1.98 g/L upon optimization of the induction conditions with the induction time at 2 h post-inoculation and the IPTG concentration of 0.8 mmol/L. Moreover, to achieve a higher titer of γ-PGA, pgsBCA was inducibly expressed in C. glutamicum F343, which shows a paramount glutamate production capacity. The final γ-PGA production reached 10.23 g/L in shake flasks and 20.08 g/L in a 5-L fermentor using glucose as the substrate. The weight-average molecular weight (Mw) of γ-PGA from recombinant strain F343 showed 34.77% higher than that produced by B. subtilis. This study provides a novel way of producing γ-PGA from sugars directly and potentiates new applications of γ-PGA in the future.


Assuntos
Corynebacterium glutamicum , Fermentação , Ácido Poliglutâmico/análogos & derivados , Açúcares
12.
Emerg Microbes Infect ; 9(1): 548-557, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32160805

RESUMO

Helicobacter pylori (H. pylori) recurrence remains a significant public health concern. The study aimed to assess H. pylori reinfection rate and identify its risk factors in China. This prospective open cohort, observational study was performed at 18 hospitals across 15 provinces in China. Consecutive patients who received the successful initial eradication during 1 January 2012 and 31 December 2018 were eligible for enrolment. H. pylori recurrence was defined as reinfection that occurred at more than the 12-month interval after successful initial eradication. Surveyed risk factors that might be associated with reinfection were preliminarily estimated by log-rank test and further determined by Cox regression model to calculate the hazard ratio (HR) and 95% confidence interval (CI). A total of 5193 subjects enrolled in the study. The follow-up intervals varied from 6 to 84 months with a general follow-up rate of 67.9%. Annual reinfection rate was 1.5% (95% CI: 1.2-1.8) per person-year. H. pylori reinfection was independently associated with the following five risk factors: minority groups (HR = 4.7, 95% CI: 1.6-13.9), the education at lower levels (HR = 1.7, 95% CI: 1.1-2.6), a family history of gastric cancer (HR = 9.9, 95% CI: 6.6-14.7), and the residence located in Western China (HR = 5.5, 95% CI: 2.6-11.5) following by in Central China (HR = 4.9, 95% CI: 3-8.1) (all P < 0.05). Reinfection rate of H. pylori in China is relatively low. Patients with specific properties of ethnic groups, education level, family history, or residence location appear to be at higher risk for reinfection.


Assuntos
Infecções por Helicobacter/virologia , Helicobacter pylori/fisiologia , Adulto , Erradicação de Doenças , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Recidiva , Fatores de Risco , Fatores de Tempo
13.
Chem Commun (Camb) ; 56(30): 4200-4203, 2020 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-32167511

RESUMO

Enantioselective dearomatization inverse-electron-demand Diels-Alder reaction/oxidation of indoles with 2-(2-nitrovinyl)-1,4-benzoquinone was realised using a chiral bisoxazoline/zinc complex as a catalyst. This transformation allowed for the synthesis of enantioenriched six-membered [2,3]-fused indolines (up to 99% yield and 88% ee).

14.
Chembiochem ; 2020 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-32180310

RESUMO

Transcription terminators play a role in terminating the progress of gene transcription, and are thus essential elements in the gene circuit. Terminators have two main functions: terminating gene transcription and improving the stability of gene transcripts during translation. We therefore considered the detailed characteristics of terminators in relation to their different roles in gene transcription and translation, including transcription shut-down degree (α) and upstream mRNA protection capacity (ß), and apparent termination efficiency (η) reflecting the overall regulatory effect of the terminator. Based on a dual-reporter gene system, we constructed three terminator-probe plasmids to investigate each characteristic in Escherichia coli. According to multiple regression analysis, the transcription shut-down degree and the upstream mRNA protection capacity contributed almost equally to the apparent termination efficiency. Sequence analysis of 12 terminators demonstrated that the terminator sequence was dominated by GC bases, and that a high ratio of GC bases in the stem structure of terminators might be associated with a high degree of transcription shut-down. This comprehensive characterization of terminators furthers our understanding of the role of terminators in gene expression and provides a guide for synthetic terminator design.

15.
Pol J Microbiol ; 69(1): 91-97, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32189484

RESUMO

The root of Paris polyphylla var. yunnanensis, a famous and endangered traditional Chinese herb, has a significant medicinal value. The aim of this study was to analyze the composition and functional characteristics of bacterial endophytes in roots, stems, and leaves of P. polyphylla var. yunnanensis. The 16S rRNA gene sequencing and functional prediction of bacterial endophytes in roots, stems, and leaves of P. polyphylla var. yunnanensis were conducted. The Chao and Shannon indices of the bacteria in roots were significantly higher than those in stems and leaves. The dominant endophyte phyla were Cyanobacteria, Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria. The main genera detected in roots were unclassified Cyanobacteria, Rhizobium, Flavobacterium, and Sphingobium; the main genera in stems were norank_c__Cyanobacteria, Bacillus, and Pseudomonas; the main genera in leaves were norank_c__Cyanobacteria and Rhizobium. The microbiota in roots was particularly enriched in functional categories "extracellular structures" and "cytoskeleton" compared with stems and leaves (p < 0.05). Our study reveals the structural and functional characteristics of the endophytic bacteria in roots, stems, and leaves of P. polyphylla var. yunnanensis, which aids in the scientific understanding of this plant.The root of Paris polyphylla var. yunnanensis, a famous and endangered traditional Chinese herb, has a significant medicinal value. The aim of this study was to analyze the composition and functional characteristics of bacterial endophytes in roots, stems, and leaves of P. polyphylla var. yunnanensis. The 16S rRNA gene sequencing and functional prediction of bacterial endophytes in roots, stems, and leaves of P. polyphylla var. yunnanensis were conducted. The Chao and Shannon indices of the bacteria in roots were significantly higher than those in stems and leaves. The dominant endophyte phyla were Cyanobacteria, Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria. The main genera detected in roots were unclassified Cyanobacteria, Rhizobium, Flavobacterium, and Sphingobium; the main genera in stems were norank_c__Cyanobacteria, Bacillus, and Pseudomonas; the main genera in leaves were norank_c__Cyanobacteria and Rhizobium. The microbiota in roots was particularly enriched in functional categories "extracellular structures" and "cytoskeleton" compared with stems and leaves (p < 0.05). Our study reveals the structural and functional characteristics of the endophytic bacteria in roots, stems, and leaves of P. polyphylla var. yunnanensis, which aids in the scientific understanding of this plant.

16.
Plant Cell Rep ; 39(5): 687-689, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32080747

RESUMO

The authors signal an error in Fig. 1b which does not show the correct set of plants and should be replaced with the included new figure.

17.
Sci Rep ; 10(1): 3182, 2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-32081869

RESUMO

This study aimed to analyze the clinical characteristics of lower extremity atherosclerotic disease (LEAD) in Chinese adult type 2 diabetes (T2D) patients, and also explored the risk factors for LEAD and developed simple-to-use nomograms for LEAD and lesion degree in these patients. We retrospectively studied 4422 patients (male = 2084; female = 2338) with T2D who were ≥50. Based on lower extremity arterial ultrasound findings, we divided the patients into three groups: normal, mild, and moderate-to-severe group. The factors related to LEAD in patients with T2D were analyzed by logistic regression analysis. The risk factors for moderate-to-severe LEAD included: high HbA1c (OR = 1.07 95% CI 1.02-1.13), diabetic peripheral neuropathy (OR = 1.93 95% CI 1.57-2.37), and diabetic retinopathy (OR = 1.26 95%CI 1.01-1.57). The overall areas under the receiver operating characteristic curves for the nomograms for predicting the risks of LEAD and moderate-to-severe LEAD in adult T2D patients were 0.793 (95%CI 0.720, 0.824) and 0.736 (95%CI 0.678, 0.795), respectively. The developed nomograms are simple to use and enable preliminary visual prediction of the risk and degree of LEAD in Chinese T2D patients over 50 years. The nomograms are accurate to a certain degree and provide a clinical basis for predicting the occurrence and progression of LEAD.

18.
Med Sci Monit ; 26: e921745, 2020 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-32062668

RESUMO

BACKGROUND Through observing the changes of indexes of the intestinal mucosal barrier and intestinal flora in rats, we explored the mechanism by which Hetiao Jianpi Decoction (HTJPD) treats antibiotic-associated diarrhea (AAD) by repairing intestinal mucosal injury and regulating intestinal flora. MATERIAL AND METHODS Samples of colon tissues were collected for HE staining. Enzyme-linked immunosorbent assay (ELISA) was used to assess levels of diamine oxidase (DAO) and D-lactic acid in rat plasma and the expression of secretory immunoglobulin A (SIgA) in colon tissue. We assessed the abundance of intestinal contents by high-throughput sequencing of the 16S rRNA gene. RESULTS Compared with the Model group, the muscle layer and intestinal mucosal edema were improved, and the continuity was restored; the levels of DAO and D-lactic acid in plasma decreased, and the SIgA level were increased in the HTJPD group. The structure of the intestinal flora changed, as indicated by increased levels of certain beneficial bacteria (Verrucomicrobia, Actinobacteria, CF231, and Akkermansia), decreased levels of pathogenic bacteria (Spirochaetes and Treponema), and increased species diversity. CONCLUSIONS By improving the permeability and immune function of the intestinal mucosa, Hetiao Jianpi decoction prevented the occurrence of AAD by repairing the intestinal mucosal damage and regulating the structure and diversity of intestinal flora.

19.
Org Biomol Chem ; 18(10): 1886-1891, 2020 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-32104832

RESUMO

Two new types of cyclic pyridinium ylides were designed and further used in reactions with azoalkenes to access structurally diverse spirocyclic compounds. A range of spiropyrazoline oxindoles could be smoothly obtained in up to 99% yield via a [4 + 1] annulation process with oxindole 3-pyridinium ylides as C1 synthons. Similarly, a series of spiropyrazoline indanones could be prepared with indanone 2-pyridinium ylides as C1 synthons. This work represents the first example of cyclic pyridinium ylides as C1 synthons for the efficient construction of spirocyclic compounds.

20.
Biosens Bioelectron ; 154: 112014, 2020 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-32056973

RESUMO

We developed a novel electrochemical biosensor for uracil-DNA glycosylase (UDG) detection based on enzyme-free and substrate-free electrocatalytic signal amplification by porphyrin-based covalent-linked nanomaterial (OAPS-Por). This OAPS-Por could not only absorb much Thionine (Thi), but also possess obvious electrocatalytic activity toward the reduction of Thi without involvement of H2O2. Sequentially, the functionalized OAPS-Por with Thi, Au nanoparticles and single-stranded DNA (OAPS-Por/Thi@AuNPs-ssDNA) was ingeniously designed as the signal probe. Meantime, the hairpin DNA (hDNA) with four uracil bases was immobilized on AuNPs/GCE via an Au-S bond. When UDG was present, the uracil in hDNA was removed and hairpin structure was unfolded. Next, the signal probes binded with the unfolded hDNA by DNA hybridization. The Thi in signal probes could generated an original electrochemical signal, which could be further amplified and output due to the robust electrocatalytic activities of OAPS-Por toward Thi. As a result, the as-constructed electrochemical biosensor had a broad linear range from 0.005 to 1 U mL-1. It also exhibited a low detection limit of 6.97 × 10-4 U mL-1. Moreover, this biosensor could be used to assay the inhibition of UDG (UGI) and the UDG activity in real samples (HeLa cell lysates and human blood serums), and demonstrated great prospect in clinical diagnostics and biomedical research.

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