LncACTdb 3.0: an updated database of experimentally supported ceRNA interactions and personalized networks contributing to precision medicine.

LncACTdb 3.0 is a comprehensive database of experimentally supported interactions among competing endogenous RNA (ceRNA) and the corresponding personalized networks contributing to precision medicine. LncACTdb 3.0 is freely available at http://bio-bigdata.hrbmu.edu.cn/LncACTdb or http://www.bio-bigdata.net/LncACTdb. We have updated the LncACTdb 3.0 database with several new features, including (i) 5669 experimentally validated ceRNA interactions across 25 species and 537 diseases/phenotypes through manual curation of published literature, (ii) personalized ceRNA interactions and networks for 16 228 patients from 62 datasets in TCGA and GEO, (iii) sub-cellular and extracellular vesicle locations of ceRNA manually curated from literature and data sources, (iv) more than 10 000 experimentally supported long noncoding RNA (lncRNA) biomarkers associated with tumor diagnosis and therapy, and (v) lncRNA/mRNA/miRNA expression profiles with clinical and pathological information of thousands of cancer patients. A panel of improved tools has been developed to explore the effects of ceRNA on individuals with specific pathological backgrounds. For example, a network tool provides a comprehensive view of lncRNA-related, patient-specific, and custom-designed ceRNA networks. LncACTdb 3.0 will provide novel insights for further studies of complex diseases at the individual level and will facilitate the development of precision medicine to treat such diseases.

Highly selective detection of deoxyribonucleic acid in living cells using RecA-green fluorescent protein-single-stranded deoxyribonucleic acid filament fluorescence resonance energy transfer probe.

A fluorescence resonance energy transfer (FRET) method was developed for double-stranded deoxyribonucleic acid (dsDNA) detection in living cells using the RecA-GFP (green fluorescent protein) fusion protein filament. In brief, the thiol-modified single-stranded DNA (ssDNA) was attached to gold nanoparticles (AuNPs); on the contrary, the prepared RecA-GFP fusion protein interacted with ssDNA. Due to the FRET between AuNPs and RecA-GFP, fluorescence of RecA-GFP fusion protein was quenched. In the presence of homologous dsDNA, homologous recombination occurred to release RecA-GFP fusion protein. Thus, the fluorescence of RecA-GFP was recovered. The dsDNA concentration was detected using fluorescence intensity of RecA-GFP. Under optimal conditions, this method could detect dsDNA activity as low as 0.015 optical density (OD) Escherichia coli cells, with a wide linear range from 0.05 to 0.9 OD cells, and the regression equation was ΔF = 342.7c + 78.9, with a linear relationship coefficient of 0.9920. Therefore, it provided a promising approach for the selective detection of dsDNA in living cells for early clinical diagnosis of genetic diseases.

A dual amplified gold nanoparticle-based biosensor for ultrasensitive and selective detection of fibrin.

Ultrasensitive, selective, and non-invasive detection of fibrin in human serum is critical for disease diagnosis. So far, the development of high-performance and ultrasensitive biosensors maintains core challenges for biosensing. Herein, we designed a novel ribbon nanoprobe for ultrasensitive detection of fibrin. The probe contains gold nanoparticles (AuNPs) that can not only link with homing peptide Cys-Arg-Glu-Lys-Ala (CREKA) to recognize fibrin but also carry long DNA belts to form G-quadruplex-based DNAzyme, catalyzing the chemiluminescence of luminol-hydrogen peroxide (H2O2) reaction. Combined with the second amplification procedure of rolling circle amplification (RCA), the assay exhibits excellent sensitivity with a detection limit of 0.04 fmol L-1 fibrin based on the 3-sigma. Furthermore, the biosensor shows high specificity on fibrin in samples because the structure of antibody-fibrin-homing peptide was employed to double recognize fibrin. Altogether, the simple and inexpensive approach may present a great potential for reliable detection of biomarkers.

First report of Phytophthora blight caused by Phytophthora nicotianae on Daphne odora in China.

The variegated leaves and fragrant flowers of Daphne odora var. marginata Mak. make it a popular garden plant. In May 2020, we found diseased D. odora plants in a greenhouse at the Ganzhou Vegetable and Flower Research Institute, in southeast China; 72% of 1800 plants had Phytophthora blight-like symptoms-shrunken stems, black withered branches, wilted and dropped leaves (Fig 1a), and rotted and dark green roots. The root and stem tissue surfaces were disinfected with 75% ethanol for 30 s followed by 0.1% HgCl2 for 1 min, rinsed thrice with sterile water, and cultured on potato-dextrose agar (PDA) medium at 25°C. Mycelia from the diseased tissue were subcultured on fresh PDA medium, providing three colonies. White colonies (~4.1 mm) were formed after 10 days at 25°C (Fig 1b). Sporangia and chlamydospores were induced by placing actively growing mycelia on PDA medium at 25°C for ~30 days and then at 45°C for ~3 days. Sporangia were ovoid to spherical and 19.33 × 20.99 µm in size (Fig 1c), whereas chlamydospores were spherical and 15.68 × 16.10 µm in size (Fig 1d). All three colonies resembled Phytophthora spp. Genomic DNA was extracted from isolates using the Ezup Column Fungi Genomic DNA Purification Kit (Sangon Biotech [Shanghai] Co. Ltd.), and rDNA-ITS and ß-tubulin were amplified and sequenced. BLAST analysis (GenBank) revealed that the ITS (Accession No. MZ676071) and ß-tubulin (MZ748503) sequences of isolates shared the highest similarity (99-100%) with those of Phytophthora nicotianae (Duccio et al. 2015). A phylogenetic tree of the relationship between our isolate hjt3 and its close relatives within the P. nicotianae species was constructed using the MEGA X neighbor-joining method (Fig 2). The pathogen was identified as P. nicotianae based on morphological and molecular characteristics. Sequencing results of the three samples were consistent, all indicating P. nicotianae. A specimen (JXAU-H2020245) was deposited in the Herbarium of the College of Agronomy, Jiangxi Agricultural University. To confirm pathogenicity, 9-month-old healthy D. odora plants were used for stem and soil inoculation. Stems were cut ~5 cm from the soil with sterilized scalpels and inoculated with 0.8 cm diameter PDA plugs containing actively growing mycelia of isolate hjt3. The soil was sterilized and 0.8 cm PDA plugs containing actively growing mycelia were buried in the soil at ~5 cm; the mycelia were in contact with the roots. Plants in both groups were treated equally; those inoculated with sterile PDA plugs served as controls. There were six plants in each group, with each experiment performed in triplicate. All plants were incubated in a greenhouse at 25-28°C. The stems shrank and began to rot rapidly after 7 days (Fig 3) and the branches turned black and withered within 2 weeks. After soil inoculation, the stems of the inoculated plants blackened and rotted in ~20 days (Fig 4) and the roots rotted and turned dark green (Fig 5). These symptoms rapidly spread to the branches. The control plants did not exhibit any symptoms. Reisolated colonies showed the same morphological traits as the isolates used for inoculation; no target colonies were isolated from the control plants. Phytophthora blight caused by P. nicotianae on D. odora has been reported in Italy (Garibaldi A, 2009) and Korea (Kwon et al. 2005). This is the first detection in China. Therefore, Phytophthora blight on D. odora caused by P. nicotianae should be monitored and controlled to promote the development of the D. odora industry.

Simple and sensitive detection of deoxyribonucleic acid using a RecA-GFP fusion protein-DNA filament as probe.

A simple, rapid and highly sensitive method for detection of double-stranded DNA (dsDNA) was developed using a novel fluorescence probe composed of a RecA-GFP fusion protein that had specific recognition of ssDNA complexes (RecA-GFP-DNA filament). The RecA-GFP fusion protein not only had strong fluorescence, but could also occur by homologous recombination. In the presence of the target dsDNA, the complementary ssDNA of the RecA-GFP-DNA filaments invaded one end of the dsDNA chain. In addition, the other end of the ssDNA dissociated the RecA-GFP filaments. An assay of the probe showed a linear relationship with dsDNA concentration in the range 1-11 nM, with a correlation coefficient of 0.9923. The limit of detection for dsDNA was determined experimentally to be 0.3 nM (3δ). Compared with conventional methods, this method has the advantages of simple operation, high specificity, and high sensitivity.

Enhancing the functional characteristics of soy protein isolate via cross-linking catalyzed by Bacillus subtilis transglutaminase.

BACKGROUND: Although Streptomyces mobaraense transglutaminase (MTG) has been extensively applied to enhance the functional characteristics of soy protein isolate (SPI) through cross-linking, various transglutaminases (TGs) in nature may provide more choice in the food industry. Previous research reported that TG derived from Bacillus subtilis (BTG) exhibited better pH stability and thermostability than MTG. RESULTS: An attempt was made to study the influence of BTG induced cross-linking on the properties of SPI. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) results indicated that almost all protein constituents (α', α, ß, AS, and BS) in SPI could be cross-linked with BTG treatment. The BTG treatment also resulted in a significant increase (*P < 0.05) in SPI mean particle size. Emulsifying activity and stability were improved from 0.11535 m2  g-1 and 48.3% for native SPI to 0.13252 m2  g-1 and 83.9% for SPI treated with BTG at 6 h. Similarly, the modified SPI showed better foam activity (1.32 mL) and stability (87.6%) than the original SPI (0.93 mL and 56.8%). The water-holding capacity of SPI gel was found to increase with time, with a value of 95.43% at 6 h. Furthermore, SPI gel's texture profiles were greatly improved by adding BTG (*P < 0.05). CONCLUSION: The results of the present study indicated that BTG could be a promising cross-linking agent for improving the functional characteristics of SPI. As a substitute for MTG, BTG could thus potentially be used for food structure engineering to enhance the functional characteristics of multiple proteins to advance the development of food chemistry. © 2020 Society of Chemical Industry.

Label-free detection of fibrinogen based on the fibrinogen-enhanced peroxidase activity of a fibrinogen-hemin composite.

A simple, label-free colorimetric method for the determination of fibrinogen (Fib) in plasma is presented. In this work, it was observed that Fib interacted with hemin to form a hemin-Fib composite. Because Fib prevented hemin from the formation of m-oxo-dimers, the hemin-Fib composite possesses excellent peroxidase-like activity. Importantly, the peroxidase-like activity of Fib-hemin increased with the increase in the Fib. This allows us to utilize the H2O2-ABTS colorimetric system for the quantitative analysis of Fib. This optimized method provided a linear determination range of 2.0-100 pM with a correlation of 0.9975. The limit of detection for Fib was experimentally determined to be 0.7 pM based on a signal-to-noise ratio (S/N) of 3. This novel approach provides a rapid, sensitive, cost efficient and robust bioassay for detection of Fib in pathology and clinical applications.

[The Advancement of Attenuated Total Reflection Fourier Transform Infrared Technology in Clinical Application].

The authors systemically reviewed the fast development of attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and its clinical application in the past decades. The advantages of this objective technique include real time scanning, easy manipulation and no harm to the subjects examined. Combined with pattern recognition methodology and further confirmation with the clinical and pathological diagnosis, the goal of fast differentiation of malignancy from benign lesions could be achieved. ATR-FTIR spectroscopy technique has shown high differential capacity for benign and malignant tissues such as thyroid, breast and pulmonary diseases. ATR-FTIR spectroscopy has being applied in investigating the differential value (the sensitivity, specificity, and accuracy) of metastatic lymph nodes in thyroid and breast cancer with encouraging results. ATR-FTIR technique would become a promising tool in tissue diagnosis intra-operatively. ATR-FTIR spectroscopy has also been widely applied in detecting bio-fluid to differentiate diseases. The serum ATR-FTIR spectroscopy has the ability of reflecting disease-related information in a fingerprint manner with little amount of blood. Several published articles have covered diseases such as glioma, chest pain, prostate cancer, renal failure, Alzheimer's disease, and ovarian cancer. The results of these researches have proved the efficacious discriminate value of this method. As ATR-FTIR spectroscopy has the potential of fast analysis, accurate diagnosis, and low cost-effective value. It would become one of the most important assisting diagnosis tools in future. Follow-up study should focus on enhancing sample quality and enlarging sample size to have further prospective clinical application.

An ultrasensitive detection of 17ß-estradiol using a gold nanoparticle-based fluorescence immunoassay.

A novel ultrasensitive amplification immunoassay for the determination of 17ß-estradiol (E2) is reported based on the nanoparticle signal amplification platform. It involves two types of particles: magnetic microparticles (MMPs) functionalized with an anti-E2 antibody produced in rabbit as a capture probe; double-codified gold nanoparticles (DC-AuNPs) modified with both goat anti-rabbit antibody and SH-dsDNA-biotin as a signal amplifier; and avidin-FITC was added to link to the SH-dsDNA-biotin as a tracer. The competitive reaction of the anti-E2 antibody immobilized on magnetic microparticles with estradiol in the sample solution and with the goat anti-rabbit antibody on double-codified gold nanoparticles results in a complex involving the DC-AuNPs and MMPs. Under optimized conditions, the linear range of E2 is from 1.0 × 10(-5) to 1.0 ng mL(-1), and the detection limit of the assay could reach up to 6.37 × 10(-6) ng mL(-1). It was applied to determine E2 in human urine, with mean percent recoveries in the range of 96.5%-107.4%, and relative standard deviations were below 8.1%.

Magnetic nanoparticles-cooperated fluorescence sensor for sensitive and accurate detection of DNA methyltransferase activity coupled with exonuclease III-assisted target recycling.

A fluorescence magnetic biosensor for the DNA methyltransferase activity was developed based on the cooperative amplification by combining the magnetic nanoparticles synergistic exonuclease III (Exo III)-assisted circular exponential amplification and a supramolecular structure ZnPPIX/G-quadruplex. First, a duplex DNA probe, which was constructed by the hybridization of a quadruplex-forming oligomer with a molecular beacon, was assembled on the magnetic nanoparticles (MNPs) as a reporter. A hairpin probe (HP)-containing sequence of GATC was used as the methylation substrate of DNA adenine methyltransferase (DAM). Once HP was methylated by DAM, it could be recognized and cleaved by Dpn I, which allows the release of a single-stranded DNA. The DNA (tDNA1) then hybridizes to the MNP probe, which then triggers the exonuclease III-mediated target exponential recycling reaction. Simultaneously, numerous quadruplex forming oligomers are liberated and folded into the G-quadruplex-ZnPPIX complexes with the help of zinc(ii)-protoporphyrin IX(ZnPPIX) on the MNP surface to give a remarkable fluorescence response. In the developed sensor, a small amount of target DAM can be converted to a large number of stable DNA triggers, leading to remarkable amplification of the target. Moreover, using MNPs as a vector of the sensor may reduce the interference from the real samples, which increases the anti-interference of the sensing system. Based on this unique amplification strategy, a very low detection limit down to 2.0 × 10(-4) U mL(-1) was obtained. Furthermore, the sensor could be used to evaluate the DAM activity in different growth stages of E. coli cells and screen Dam MTase inhibitors. Therefore, the strategy proposed here provides a promising platform for monitoring the activity and inhibition of DNA MTases and has great potential to be applied further in early clinical diagnostics and medical research.

[Research on Application of Fourier Transform Infrared Spectrometry in the Diagnosis of Lymph Node Metastasis in Gastric Cancer].

To explore the feasibility of quick intraoperative in situ and noninvasive diagnosis of lymph node metastasis in gastric cancer by Fourier transform infrared (FTIR) spectrometry. FTIR spectra of surgically removed fresh lymph nodes were measured by FTIR via probe of attenuated total reflection (ATR). For each spectrum, 13 bands were indentified and assigned between 3 000 and 1 000 cm(-1). Peaks in the spectra were measured and relative intensity ratios were calculated and compared between the spectra of Metastatic lymph nodes (MLN) and Non-metastatic lymph nodes (NMLN). Standard statistic analysis was performed. 720 lymph nodes were measured in 38 gastric cancer patients. Results show that there were significant differences between the FTIR of 540 MLN and 180 NMLN. (1) For the band related to nucleic acid: The ratios of I1240/I1460 (p = 0.015) and I1080/I1460 (p = 0.034) increased in MLN, which shows that the relative quantity of nucleic acid was more in MLN than that in NMLN. (2) For the bands related to protein: The ratios of I1640 /I1460 (p = 0.001) and I146/I1460 (p = 0.027) increased in MLN, which shows that the relative quantity of protein was more in MLN. (3) For the bands related to lipid: The ratio of I2855/I460 and I1740/I1460 decreased in MLN FTIR spectrum, indicating the lower relative quantity of lipid in MLN. (4) For the bands related to carbohydrate: The ratio of I1160/I1460 (p = 0.023) decreased in MLN FTIR spectrum, indicating the lower relative quantity of carbohydrate in MLN. The results demonstrate that the FTIR spectroscopy technique maybe develop into a promising method for in situ and quick intraoperative differential diagnosis of lymph node metastasis in gastric cancer.

A comprehensive database of exosome molecular biomarkers and disease-gene associations.

Exosomes play a crucial role in intercellular communication and can be used as biomarkers for diagnostic and therapeutic clinical applications. However, systematic studies in cancer-associated exosomal nucleic acids remain a big challenge. Here, we developed ExMdb, a comprehensive database of exosomal nucleic acid biomarkers and disease-gene associations curated from published literature and high-throughput datasets. We performed a comprehensive curation of exosome properties including 4,586 experimentally supported gene-disease associations, 13,768 diagnostic and therapeutic biomarkers, and 312,049 nucleic acid subcellular locations. To characterize expression variation of exosomal molecules and identify causal factors of complex diseases, we have also collected 164 high-throughput datasets, including bulk and single-cell RNA sequencing (scRNA-seq) data. Based on these datasets, we performed various bioinformatics and statistical analyses to support our conclusions and advance our knowledge of exosome biology. Collectively, our dataset will serve as an essential resource for investigating the regulatory mechanisms of complex diseases and improving the development of diagnostic and therapeutic biomarkers.

Detection of lung cancer tissue by attenuated total reflection-Fourier transform infrared spectroscopy-a pilot study of 60 samples.

BACKGROUND: Attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy could serve as a diagnostic tool for detecting and discriminating different diseases. The aim of this preliminary study was to distinguish malignant and nonmalignant lung tissues with ATR-FTIR spectroscopy. METHODS: Sixty lung tissue samples were obtained from 30 patients who underwent pulmonary lobectomy. Samples were examined with ATR-FTIR spectroscopy before histologic diagnosis. Peak positions, intensities, and full width at half maximum of each absorbent band were measured, and the relative intensity ratios were calculated. Canonical discriminant analysis was performed to discriminate malignant and nonmalignant groups. RESULTS: Twenty-two parameters were significantly different between malignant and nonmalignant groups. Peak intensity at 1546/cm, intensity ratio at 1120/cm, and full width at half maximum at 1303 and 1240/cm were selected as independent factors to form discriminant functions. The sensitivity and specificity of the discriminants were all 96.7%. CONCLUSIONS: ATR-FTIR spectroscopy is a promising method for the detection of malignant lung tissue and could be proved useful in lung tumor surgery.

Characterization of tumour microenvironment reprogramming reveals invasion in epithelial ovarian carcinoma.

BACKGROUND: Patients with epithelial ovarian carcinoma (EOC) are usually diagnosed at an advanced stage with tumour cell invasion. However, identifying the underlying molecular mechanisms and biomarkers of EOC proliferation and invasion remains challenging. RESULTS: Herein, we explored the relationship between tumour microenvironment (TME) reprogramming and tissue invasion based on single-cell RNA sequencing (scRNA-seq) datasets. Interestingly, hypoxia, oxidative phosphorylation (OXPHOS) and glycolysis, which have biologically active trajectories during epithelial mesenchymal transition (EMT), were positively correlated. Moreover, energy metabolism and anti-apoptotic activity were found to be critical contributors to intratumor heterogeneity. In addition, HMGA1, EGR1 and RUNX1 were found to be critical drivers of the EMT process in EOC. Experimental validation revealed that suppressing EGR1 expression inhibited tumour cell invasion, significantly upregulated the expression of E-cadherin and decreased the expression of N-cadherin. In cell components analysis, cancer-associated fibroblasts (CAFs) were found to significantly contribute to immune infiltration and tumour invasion, and the accumulation of CAFs was associated with poorer patient survival. CONCLUSION: We revealed the molecular mechanism and biomarkers of tumour invasion and TME reprogramming in EOC, which provides effective targets for the suppression of tumour invasion.

Label-free fluorescence method for screening G-quadruplex ligands.

G-quadruplex ligands can interfere with the telomere structure, telomere elongation/replication, and proliferation of cancer cells. A key element in the development of potent G-quadruplex ligands is the screening of large chemical libraries of potential candidates. Here, we describe a simple fluorescence method for screening of G-quadruplex ligands. The method is based on the ability of G-quadruplex ligands to displace hemin from G-quadruplex-based DNAzyme, resulting in a decrease of its catalytic activity on the fluorescence-developing reaction between p-hydroxyphenylacetic acid and H(2)O(2). The method eliminates the requirement for expensive and time-consuming preparation of labeled DNA. Our method provides a simple, cheap, and sensitive approach to screen G-quadruplex ligands (potential antitumor drugs).

Identification of colitis and cancer in colon biopsies by Fourier Transform Infrared spectroscopy and chemometrics.

Cancer is a disease that does great harms to the health of human beings. FT-IR spectroscopy could identify variability at the molecular level in biological specimens. It is a rapid and noninvasive method, which could be used intraoperatively to modify surgical procedures. The aim of this paper is to identify and separate cancer from colitis in endoscopic colon biopsies through the use of FT-IR spectroscopy. A total of 88 endoscopic colon samples, including 41 cases of colitis and 47 cases of colon cancer, were obtained. Specimens were placed on an ATR accessory linked to FT-IR spectrometer with a MCT detector for greater stability and sensitivity. Later, specimens were sent for the histological examination as the reference in the spectral analysis. 41 colitis and 47 cancer specimens were compared. Spectra preprocessed with smoothing and normalization were used for discrimination analysis. PCA was processed to simplify the spectrum data set. Naive Bayes classifier model was constructed for diagnostic classification. Leave-one-out cross-validation method was utilized to assess the discrimination results. The sensitivity of FT-IR detection for cancer achieves 97.6%. The results showed that colon cancer could be distinguished from colitis with high accuracy using FT-IR spectroscopy and chemometrics.

Homing peptide combined with DNAzyme-based ELISA-like assay for highly specific and sensitive detection of fibrin.

A highly sensitive and specific ELISA-like chemiluminescence method for detection of fibrin has been developed. In the sensing platform, the homing peptide (CREKA), as recognition molecule, which can specially recognize the fibrin on microtiter plate, combined with G-quadruplex-based DNAzyme to form the probe of G-quadruplex-hemin DNAzyme-CREKA. After the sample solution was coated on the plates, the probe was crosslinked with fibrin through the interaction of CREKA and fibrin. Finally, luminol-H2O2 chemiluminesecence (CL) reaction was exploited for quantitative analysis of fibrin. The liner range for fibrin detection was from 0.112 pmol L-1 to 5.6 pmol L-1 with the detection limit of fibrin as low as 0.04 pmol L-1, based on a signal-to-noise ratio (S/N) of 3. Furthermore, on the basis of the high amplification efficiency of the rolling circle amplification (RCA) reaction, the method enabled to analyze fibrin with a detection limit corresponding to 0.06 fmol L-1, whose sensitivity increased 3 orders of magnitude than that of above method in the absence of RCA reaction. In particular, combined with the separation and washing steps of ELISA, the proposed method possessed higher selectivity, high-throughput and low cost, which shows promise for applications in clinical diagnosis.

Crosslinking Mechanism on a Novel Bacillus cereus Transglutaminase-Mediated Conjugation of Food Proteins.

Until now, Streptoverticillium mobaraense transglutaminase (TG) is the only commercialized TG, but limited information is known about its selection tendency on crosslinking sites at the protein level, restricting its application in the food industry. Here, four recombinant Bacillus TGs were stable in a broad range of pH (5.0−9.0) and temperatures (<50 °C), exhibiting their maximum activity at 50−60 °C and pH 6.0−7.0. Among them, TG of B. cereus (BCETG) demonstrated the maximal specific activity of 177 U/mg. A structural analysis indicated that the Ala147-Ala156 region in the substrate tunnel of BCETG played a vital role in catalytic activity. Furthermore, bovine serum albumin, as well as nearly all protein ingredients in soy protein isolate and whey protein, could be cross-linked by BCETG, and the internal crosslinking paths of three protein substrates were elucidated. This study demonstrated Bacillus TGs are a candidate for protein crosslinking and provided their crosslinking mechanism at the protein level for applications in food processing.

Intraoperative detection of thyroid carcinoma by fourier transform infrared spectrometry.

BACKGROUND: Fourier transform infrared (FTIR) spectroscopy is a powerful tool for distinguishing cancerous tissue from normal one. Our aim in this study was to establish tissue discriminant analysis for thyroid malignancy and benign samples intraoperatively using FTIR spectroscopy. METHODS: Seventeen papillary thyroid cancer and 43 nodular goiter tissues were obtained and underwent FTIR spectroscopy scanning intraoperatively. Nine peak positions were identified and assigned. Peak position values and wave intensity ratios were measured in every single spectrum. Data of malignant and benign groups were compared and equations of canonical discriminant analysis were established. RESULTS: Peak positions of P1640, P1240, P1550, and peak intensity ratios of I3375/I1460, I1640/I1460, I1400/I1460, I1550/I1080, I1080/I1460, and I1640/I1550 of thyroid papillary carcinoma group are significantly different from nodular goiter group. The sensitivity, specificity, and accuracy rate of the discriminants are 83.3%, 95.2%, and 91.67%, respectively. CONCLUSION: FTIR spectroscopy technique in combination with canonical discriminant analysis method can achieve fast and accurate discrimination for malignant and benign thyroid nodules during operation.

Label-free fluorescent detection of thrombin using G-quadruplex-based DNAzyme as sensing platform.

We report herein a label-free and sensitive fluorescent method for detection of thrombin using a G-quadruplex-based DNAzyme as the sensing platform. The thrombin-binding aptamer (TBA) is able to bind hemin to form the G-quadruplex-based DNAzyme, and thrombin can significantly enhance the activity of the G-quadruplex-based DNAzyme. The G-quadruplex-based DNAzyme is found to effectively catalyze the H(2)O(2)-mediated oxidation of thiamine, giving rise to fluorescence emission. This allows us to utilize the H(2)O(2)-thiamine fluorescent system for the quantitative analysis of thrombin. The assay shows a linear toward thrombin concentration in the range of 0.01-0.12 nM. The present limit of detection for thrombin is 1 pM, and the sensitivity for analyzing thrombin is improved by about 10,000-fold as compared with the reported colorimetric counterpart. The work also demonstrates that thiamine is an excellent substrate for the fluorescence assay using the G-quadruplex-based DNAzyme as the sensing platform.