Microenvironment-Sensitive Fluorescent Ligand Binds Ascaris Telomere Antiparallel G-Quadruplex DNA with Blue-Shift and Enhanced Emission.

The development of small molecules that can selectively target G-quadruplex (G4) DNAs has drawn considerable attention due to their unique physiological and pathological functions. However, only a few molecules have been found to selectively bind a particular G4 DNA structure. We have developed a fluorescence ligand Q1, a molecular scaffold with a carbazole-pyridine core bridged by a phenylboronic acid side chain, that acts as a selective ascaris telomere antiparallel G4 DNA ASC20 ligand with about 18 nm blue-shifted and enhanced fluorescence intensity. Photophysical properties revealed that Q1 was sensitive to the microenvironment and gave the best selectivity to ASC20 with an equilibrium binding constant Ka =6.04×105  M-1 . Time-resolved fluorescence studies also demonstrated that Q1 showed a longer fluorescence lifetime in the presence of ASC20. The binding characteristics of Q1 with ASC20 were shown in detail in a fluorescent intercalator displacement (FID) assay, a 2-Ap titration experiment and by molecular docking. Ligand Q1 could adopt an appropriate pose at terminal G-quartets of ASC20 through multiple interactions including π-π stacking between aromatic rings; this led to strong fluorescence enhancement. In addition, a co-staining image showed that Q1 is mainly distributed in the cytoplasm. Accordingly, this work provides insights for the development of ligands that selectively targeting a specific G4 DNA structure.

Design, synthesis and mechanistic studies of a TICT based fluorogenic probe for lighting up protein HSA.

Human serum albumin (HSA) in blood serves as an important biomarker for clinical diagnosis, and fluorescence sensing method has attracted extensive attention. In this work, a small organic molecule probe, YS8, involving twisted intramolecular charge transfer (TICT) characteristic, was designed and investigated to detect HSA. YS8 kept silent state in fluorescence under physiological conditions, but the encapsulation of YS8 in the hydrophobic subdomain IB region of HSA inhibited the TICT state and produced a clear light-up fluorescent signal. Especially, YS8 was demonstrated to be an efficient fluorogenic probe to discriminate HSA from other proteins including the bovine serum albumin (BSA). Moreover, YS8/HSA complex could be applied in fluorescence imaging in living cells and is also useful in the study of artificial fluorescent protein (AFP).

Distribution of human papillomavirus genotypes in western China and their association with cervical cancer and precancerous lesions.

The aim of this study was to describe the distribution of human papillomavirus (HPV) genotypes among cervical cancers and pre-cancers in Shaanxi province of western China. A total of 17,341 women who were screened for cervical cancer from January 2014 to December 2016, using HPV genotyping and ThinPrep cytologic test were included. The prevalence and attribution of HPV genotypes were stratified by cervical lesion and age group. Of the subjects, 26.3% were infected with HPV, 28.0% of whom had multiple infections. The crude HPV prevalence increased from atypical squamous cells of undetermined significance/low-grade squamous intraepithelial lesions (ASCUS/LSIL, 64.3%) to high-grade squamous intraepithelial lesions (HSIL, 79.8%) and to invasive cervical cancer (ICC, 89.7%, P < 0.001). The three most prevalent genotypes were HPV 16 (8.0%), 58 (4.2%), and 52 (4.0%), and HPV 16, 31 and 33 were positively correlated with increased severity of cervical lesions. Additionally, the divalent vaccine genotypes HPV 16 and 18 accounted for 68.2% of ICC cases. Although 78.5% of ICC and 60.3% of HSIL cases were attributed to 9-valent vaccine genotypes, the other genotypes not covered by any vaccine still resulted in increases in coverage, with 1.5% for ICC, 5.3% for HSIL, and 13.5% for ASCUS/LSIL. HPV prevalence in western China was consistent with other regions of China. Early vaccination with 9-valent HPV vaccine is recommended in this locality for females younger than 26 years with no prior infection, while divalent the vaccine is more appropriate for women between 26 and 45 years, considering the efficacy, safety and cost-effectiveness of vaccines.

Effect of Helicobacter pylori on gastrointestinal microbiota: a population-based study in Linqu, a high-risk area of gastric cancer.

OBJECTIVE: Gastrointestinal microbiota may be involved in Helicobacter pylori-associated gastric cancer development. The aim of this study was to explore the possible microbial mechanisms in gastric carcinogenesis and potential dysbiosis arising from H. pylori infection. DESIGN: Deep sequencing of the microbial 16S ribosomal RNA gene was used to investigate alterations in paired gastric biopsies and stool samples in 58 subjects with successful and 57 subjects with failed anti-H. pylori treatment, relative to 49 H. pylori negative subjects. RESULTS: In H. pylori positive subjects, richness and Shannon indexes increased significantly (both p<0.001) after successful eradication and showed no difference to those of negative subjects (p=0.493 for richness and p=0.420 for Shannon index). Differential taxa analysis identified 18 significantly altered gastric genera after eradication. The combination of these genera into a Microbial Dysbiosis Index revealed that the dysbiotic microbiota in H. pylori positive mucosa was associated with advanced gastric lesions (chronic atrophic gastritis and intestinal metaplasia/dysplasia) and could be reversed by eradication. Strong coexcluding interactions between Helicobacter and Fusobacterium, Neisseria, Prevotella, Veillonella, Rothia were found only in advanced gastric lesion patients, and were absent in normal/superficial gastritis group. Changes in faecal microbiota included increased Bifidobacterium after successful H. pylori eradication and more upregulated drug-resistant functional orthologs after failed treatment. CONCLUSION: H. pylori infection contributes significantly to gastric microbial dysbiosis that may be involved in carcinogenesis. Successful H. pylori eradication potentially restores gastric microbiota to a similar status as found in uninfected individuals, and shows beneficial effects on gut microbiota.

Synthesis of amino acid derivatives of 5-alkoxy-3,4-dihalo-2(5H)-furanones and their preliminary bioactivity investigation as linkers.

A series of amino acid derivatives are successfully synthesized via a metal-free C-N coupling reaction of 5-alkoxy-3,4-dihalo-2(5H)-furanones and amino acids. Their structures are well characterized with 1H NMR, 13C NMR, ESI-MS and elemental analysis. As potential linkers of the 2(5H)-furanone unit with other drug moieties containing a hydroxyl or amino group, the effect of amino acids is investigated by comparison with other 2(5H)-furanone compounds by constructing C-O/C-S bonds. The preliminary results of the biological activity assay by the MTT method on a series of cancer cell lines in vitro reveal that the introduction of amino acids basically has no toxic effect. This can lead to these 2(5H)-furanone derivatives being further well-linked with other bioactive moieties with amino or hydroxy groups as expected. Thus, the biological activity assay gives a direction for the design of bioactive 2(5H)-furanones based on these amino acid linkers.

Metabolite Alterations and Interactions with Microbiota in Helicobacter pylori-Associated Gastric Lesions.

Metabolites and their interactions with microbiota may be involved in Helicobacter pylori-associated gastric lesion development. This study aimed to explore metabolite alterations upon H. pylori eradication and possible roles of microbiota-metabolite interactions in progression of precancerous lesions. Targeted metabolomics assays and 16S rRNA gene sequencing were conducted to investigate metabolic and microbial alterations of paired gastric biopsy specimens in 58 subjects with successful and 57 subjects with failed anti-H. pylori treatment. Integrative analyses were performed by combining the metabolomics and microbiome profiles from the same intervention participants. A total of 81 metabolites were significantly altered after successful eradication compared to failed treatment, including acylcarnitines, ceramides, triacylglycerol, cholesterol esters, fatty acid, sphingolipids, glycerophospholipids, and glycosylceramides, with P values of <0.05 for all. The differential metabolites showed significant correlations with microbiota in baseline biopsy specimens, such as negative correlations between Helicobacter and glycerophospholipids, glycosylceramide, and triacylglycerol (P < 0.05 for all), which were altered by eradication. The characteristic negative correlations between glycosylceramides and Fusobacterium, Streptococcus, and Gemella in H. pylori-positive baseline biopsy specimens were further noticed in active gastritis and intestinal metaplasia (P < 0.05 for all). A panel including differential metabolites, genera, and their interactions may help to discriminate high-risk subjects who progressed from mild to advanced precancerous lesions in short-term and long-term follow-up periods with areas under the curve (AUC) of 0.914 and 0.801, respectively. Therefore, our findings provide new insights into the metabolites and microbiota interactions in H. pylori-associated gastric lesion progression. IMPORTANCE In this study, a panel was established including differential metabolites, genera, and their interactions, which may help to discriminate high-risk subjects for progression from mild lesions to advanced precancerous lesions in short-term and long-term follow-up.

Performance of circulating methylated Septin9 gene DNA in diagnosis and recurrence monitoring of colorectal cancer in Western China.

BACKGROUND AND AIMS: Methylated Septin9 (mSEPT9) has been suggested for CRC detection. To assess the performance of mSEPT9 in Western China, we compared its diagnostic and recurrence monitoring values with fecal occult blood test (FOBT), carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA 19-9). MATERIAL AND METHODS: Overall 300 subjects including 209 CRC patients and 91 healthy subjects, who have performed mSEPT9, FOBT, CEA and CA19-9 tests, were involved. Sensitivity, specificity, and area under the ROC curve (AUC) were used to evaluate the efficacy of each method. RESULTS: Plasma mSEPT9 demonstrated an AUC of 0.860, and a sensitivity of 76.4 % for CRC detection. The sensitivity of mSEPT9 was higher than FOBT, CEA and CA 19-9. Though mSEPT9 presented a larger or equal sensitivity for stage Ⅱ-IV CRCs, FOBT showed a better sensitivity for stage I CRCs. Logistical analysis showed the ones with positive mSEPT9, FOBT and CEA were more likely to have CRC (all P < 0.01). Then, the three biomarkers built the nomogram predicting the probability of having CRC. The sensitivity of mSEPT9 was also much higher than CEA for CRC recurrence monitoring. CONCLUSION: The mSEPT9 test performed better than traditional tests for CRC detection, and should be recommended for FOBT-positive ones or individuals who refuse FOBT.

Amphiphilic BODIPY-based nanoparticles as "light-up" fluorescent probe for PAEs detection by an aggregation/disaggregation approach.

Phthalic acid eaters (PAEs) play the role of plasticizer and have been widely used in the industrial and plastic production process. But due to not chemically bound in the polymeric matrix, PAEs can be easily released directly and/or indirectly into the environment, and pose a threat the ecosystem and human health. Small-molecule self-assembled nanoparticles have drawn more and more attention due to advantages of precise molecular structure, biocompatibility, great diversity, and tunability in optical properties and functionalities. Here we report the use of disaggregation-induced emission (DIE) based supramolecular assembly to design organic nanoprobe for detection PAEs. In the water solution, the designed small organic fluorophore AJ-1 was aggregated via noncovalent forces to form fluorescence off nanoparticles, but in the presence of PAEs, they disaggregated and produced a clear light-up fluorescent signal. The detection of PAEs with selectivity, sensitivity and rapid response were further achieved. The experiment of recovery of PAEs in real-water sample illustrated the practicability of probe AJ-1 in real-world applications. Besides, cellular uptake assay suggested that AJ-1 could pass through membrane and gather in the cytoplasm.

Microbiota alteration at different stages in gastric lesion progression: a population-based study in Linqu, China.

In addition to Helicobacter pylori (H.pylori), gastric microbiota may be involved in carcinogenesis process. However, the longitudinal study to assess changes in the gastric microbiota associated with the development of gastric carcinogenesis is still limited. The aim of this study is to explore dynamic microbial alterations in gastric cancer (GC) development based on a 4-year endoscopic follow-up cohort in Linqu County, China. Microbial alterations were investigated by deep sequencing of the microbial 16S ribosomal RNA gene in 179 subjects with various gastric lesions, and validated in paired gastric biopsies prospectively collected before and after lesion progression and in non-progression controls. Significant differences were found in microbial diversity and community structure across various gastric lesions, with 62 candidate differential taxa between at least two lesion groups. Further validations identified Helicobacter, Bacillus, Capnocytophaga and Prevotella to be associated with lesion progression-to-dysplasia (DYS)/GC (all P < 0.05), especially for subjects progressing from intestinal metaplasia (IM) to DYS/GC. The combination of the four genera in a microbial dysbiosis index showed a significant difference after lesion progression-to-DYS/GC compared to controls (P = 0.027). The panel including the four genera identified subjects after progression-to-DYS/GC with an area under the receiver-operating curve (AUC) of 0.941. Predictive significance was found before lesion progression-to-DYS/GC with an AUC = 0.776 and an even better AUC (0.927) for subjects progressing from IM to DYS/GC. Microbiota may play different roles at different stages in gastric carcinogenesis. A panel of bacterial genera associated with gastric lesions may help to assess gastric microbial dysbiosis and show potential predictive values for lesion progression. Our findings provide new clues for the microbial mechanism of H.pylori-associated carcinogenesis.

Quick construction of a C-N bond from arylsulfonyl hydrazides and Csp2-X compounds promoted by DMAP at room temperature.

An efficient approach for C-N bond construction by the coupling reaction of arylsulfonyl hydrazides and Csp2-X compounds is described for the first time with good yields at room temperature. The reaction promoted by the simple base DMAP displays excellent regioselectivity as well as high functional group tolerance with 41 examples. Even for inactive Csp2-Cl compounds, the metal-free transformation also affords a satisfactory yield after prolonging the reaction time, which is comparable to that of the corresponding Csp2-Br compound. The good effect of DMAP and its action mechanism are confirmed by the competitive experiments of reactivity between Cl-substituted and Br-substituted substrates and the single-crystal X-ray analysis of the key intermediate quaternary ammonium salt. Importantly, the application of this method for a gram-scale (even over 10 g) preparation can be accomplished.

Association Between Gut Microbiota and Helicobacter pylori-Related Gastric Lesions in a High-Risk Population of Gastric Cancer.

Eradication of Helicobacter pylori has been found to be effective for gastric cancer prevention, but uncertainties remain about the possible adverse consequences such as the potential microbial dysbiosis. In our study, we investigated the association between gut microbiota and H. pylori-related gastric lesions in 47 subjects by deep sequencing of microbial 16S ribosomal RNA (rRNA) gene in fecal samples. The dominant phyla in fecal samples were Bacteroidetes, Firmicutes, and Proteobacteria with average relative abundances of 54.77, 31.37 and 12.91%, respectively. Microbial diversity analysis showed that observed species and Shannon index were increased in subjects with past or current H. pylori infection compared with negative subjects. As for the differential bacteria, the average relative abundance of Bacteroidetes was found to significantly decrease from H. pylori negative (66.16%) to past infection group (33.01%, p = 0.007), as well as from normal (76.49%) to gastritis (56.04%) and metaplasia subjects (46.83%, p = 0.027). For Firmicutes and Proteobacteria, the average relative abundances showed elevated trends in the past H. pylori infection group (47.11, 20.53%) compared to negative group (23.44, 9.05%, p = 0.068 and 0.246, respectively), and similar increased trends were also found from normal (18.23, 5.05%) to gastritis (35.31, 7.23%, p = 0.016 and 0.294, respectively) or metaplasia subjects (32.33, 20.07%, both p < 0.05). These findings suggest that the alterations of fecal microbiota, especially the dominant phyla of Bacteroidetes, Firmicutes and Proteobacteria, may be involved in the process of H. pylori-related gastric lesion progression and provide hints for future evaluation of microbial changes after H. pylori eradication.

Toll-like receptor 1 and 10 polymorphisms, Helicobacter pylori susceptibility and risk of gastric lesions in a high-risk Chinese population.

Genetic polymorphisms of Toll-like receptor (TLR) 1 and 10 may influence Helicobacter pylori (H. pylori) susceptibility. To evaluate associations between TLR1 and 10 polymorphisms, H. pylori infection, and precancerous gastric lesions, a population-based study was conducted in a high-risk Chinese population. Three single-nucleotide polymorphisms, TLR1 rs4833095, TLR10 rs10004195, and TLR10 rs4129009 were genotyped by TaqMan SNP genotyping assay in 2553 participants with diverse gastric lesions. The status of H. pylori infection was determined by (13)C-urea breath test. TLR1 rs4833095 T and TLR10 rs10004195 T alleles were the minor alleles and showed in linkage disequilibrium (D'=0.98, r(2)=0.73) in the Chinese population. A decreased risk of H. pylori infection was observed in subjects with TLR1 rs4833095 CT genotype [adjusted odds ratio (OR)=0.80; 95% confidence interval (CI): 0.66-0.96] or T allele (OR=0.82; 95%CI: 0.69-0.99). Moreover, subjects carrying TLR1 rs4833095 TT genotype were associated with reduced risks of chronic atrophic gastritis (CAG, OR=0.66; 95%CI: 0.45-0.97) and intestinal metaplasia (IM, OR=0.57; 95%CI: 0.36-0.90). The risk of CAG was also decreased in subjects carrying TLR10 rs10004195 T allele (OR=0.75; 95%CI: 0.57-0.99). Furthermore, haplotype analysis indicated that haplotype TT of rs4833095 and rs10004195 had a protective effect on H. pylori infection (OR=0.83; 95%CI: 0.72-0.96) or precancerous gastric lesions (OR=0.78; 95%CI: 0.64-0.96 for CAG, and OR=0.74; 95%CI: 0.57-0.96 for IM). These findings suggest that TLR1 rs4833095 and TLR10 rs10004195 may play crucial roles in H. pylori susceptibility and gastric pathogenesis.

Post-modification of covalent organic framework functionalized aminated carbon nanotubes with active site (Fe) for the sensitive detection of luteolin.

In this research, the TT-COF(Fe)@NH2-CNTs was innovatively prepared through a post-modification synthetic process functionalized TT-COF@NH2-CNTs with active site (Fe), where TT-COF@NH2-CNTs was prepared via a one-pot strategy using 5,10,15,20-tetrakis (para-aminophenyl) porphyrin (TTAP), 2,3,6,7-tetra (4-formylphenyl) tetrathiafulvalene (TTF) and aminated carbon nanotubes (NH2-CNTs) as raw materials. The complex TT-COF(Fe)@NH2-CNTs material possessed porous structures, outstanding conductivity and rich catalytic sites. Thus, it can be adopted to construct electrochemical sensor with glassy carbon electrode (GCE). The TT-COF(Fe)@NH2-CNTs/GCE can selectively detect luteolin (Lu) with a wide linear plot ranging from 0.005 to 3 µM and a low limit of detection (LOD) of 1.45 nM (S/N = 3). The Lu residues in carrot samples were determined using TT-COF(Fe)@NH2-CNTs sensor and UV-visible (UV-Vis) approach. This TT-COF(Fe)@NH2-CNTs/GCE sensor paves the way for the quantification of Lu through a cost-efficient and sensitive electrochemical approach, which can make a significant step in the sensing field based on crystalline COFs.