Recent Advances in Electrochemiluminescence Biosensors for MicroRNA Detection.

Electrochemiluminescence (ECL) as an analytical technology with a perfect combination of electrochemistry and spectroscopy has received considerable attention in bioanalysis due to its high sensitivity and broad dynamic range. Given the selectivity of bio-recognition elements and the high sensitivity of the ECL analysis technique, ECL biosensors are powerful platforms for the sensitive detection of biomarkers, achieving the accurate prognosis and diagnosis of diseases. MicroRNAs (miRNAs) are crucial biomarkers involved in a variety of physiological and pathological processes, whose aberrant expression is often related to serious diseases, especially cancers. ECL biosensors can fulfill the highly sensitive and selective requirements for accurate miRNA detection, prompting this review. The ECL mechanisms are initially introduced and subsequently categorize the ECL biosensors for miRNA detection in terms of the quenching agents. Furthermore, the work highlights the signal amplification strategies for enhancing ECL signal to improve the sensitivity of miRNA detection and finally concludes by looking at the challenges and opportunities in ECL biosensors for miRNA detection.

Metal-Organic Framework-Loaded Engineering DNAzyme for the Self-Powered Amplified Detection of MicroRNA.

DNAzyme shows great promise in designing a highly sensitive and specific sensing platform; however, the low cellular uptake efficiency, instability, and especially the insufficient cofactor supply inhibit the intracellular molecule sensor applications. Herein, we demonstrate a novel type of DNAzyme-based self-driven intracellular sensor for microRNA (miRNA) detection in living cells. The sensor consists of a metal-organic framework [zeolite imidazole framework (ZIF-8)] core loaded with a shell consisting of a rationally designed DNAzyme, where the substrate strand is modified with FAM and BHQ-1 nearby both the sides of the restriction site, respectively, while the enzyme strand consists of two separate strands with a complementary fragment to the substrate strand and the targeting miRNA, respectively. The ZIF-8 nanoparticles enable the efficient delivery of DNAzyme into the cell and protect the DNAzyme from degradation. The pH-responsive ZIF-8 degradation is accompanied with the release of the DNAzyme and Zn2+ cofactors, and the intracellular target miRNAs recognize and activate the DNAzyme driven by the Zn2+ cofactors to cleave the substrate strand, resulting in the release of the FAM-labeled shorter product strand and increased fluorescence for miRNA detection. The self-driven approach can be generally applied to various miRNAs' detection through DNAzyme engineering.

Recent Advances in Near-Infrared-II Fluorescence Imaging for Deep-Tissue Molecular Analysis and Cancer Diagnosis.

Fluorescence imaging with high sensitivity and minimal invasiveness has received tremendous attention, which can accomplish visualized monitoring and evaluation of cancer progression. Compared with the conventional first near-infrared (NIR-I) optical window (650-950 nm), fluorescence imaging in the second NIR optical window (NIR-II, 950-1700 nm) exhibits deeper tissue penetration capability and higher temporal-spatial resolution with lower background interference for achieving deep-tissue in vivo imaging and real-time monitoring of cancer development. Encouraged by the significant preponderances, a variety of multifunctional NIR-II fluorophores have been designed and fabricated for sensitively imaging biomarkers in vivo and visualizing the treatment procedure of cancers. In this review, the differences between NIR-I and NIR-II fluorescence imaging are briefly introduced, especially the advantages of NIR-II fluorescence imaging for the real-time visualization of tumors in vivo and cancer diagnosis. An important focus is to summarize the NIR-II fluorescence imaging for deep-tissue biomarker analysis in vivo and tumor tissue visualization, and a brief introduction of NIR-II fluorescence imaging-guided cancer therapy is also presented. Finally, the significant challenges and reasonable prospects of NIR-II fluorescence imaging for cancer diagnosis in clinical applications are outlined.

Two New Prenylated Indole Diterpenoids from Tolypocladium sp. and Their Antimicrobial Activities.

Two new prenylated indole diterpenoids, tolypocladins K and L (1 and 2), together with a known analog terpendole L (3), were isolated from the solid fermentation culture of a mine soil-derived fungus Tolypocladium sp. XL115. Their structures and relative configurations were determined by comprehensive spectroscopic data analysis, as well as by comparison of their NMR data with those related known compounds. Compound 3 exhibited remarkable antibacterial activity against Micrococcus luteus with an MIC value of 6.25 µg/mL, and compounds 1 and 3 displayed moderate antifungal activity selectively against tested strains with MIC values of 25-50 µg/mL.

The Role and Impact of Deep Learning Methods in Computer-Aided Diagnosis Using Gastrointestinal Endoscopy.

At present, the application of artificial intelligence (AI) based on deep learning in the medical field has become more extensive and suitable for clinical practice compared with traditional machine learning. The application of traditional machine learning approaches to clinical practice is very challenging because medical data are usually uncharacteristic. However, deep learning methods with self-learning abilities can effectively make use of excellent computing abilities to learn intricate and abstract features. Thus, they are promising for the classification and detection of lesions through gastrointestinal endoscopy using a computer-aided diagnosis (CAD) system based on deep learning. This study aimed to address the research development of a CAD system based on deep learning in order to assist doctors in classifying and detecting lesions in the stomach, intestines, and esophagus. It also summarized the limitations of the current methods and finally presented a prospect for future research.

Two new alkylated furan derivatives with antifungal and antibacterial activities from the plant endophytic fungus Emericella sp. XL029.

Two new alkylated furan derivatives, 5-(undeca-3',5',7'-trien-1'-yl)furan-2-ol (1) and 5-(undeca-3',5',7'-trien-1'-yl)furan-2-carbonate (2), were isolated from the crude extract of the plant endophytic fungus Emericella sp. XL029 associated with the leaves of Panax notoginseng. The anti-agricultural pathogenic fungal assay indicated that compound 1 displayed significant activity against all tested fungi with minimum inhibitory concentrations (MIC) values from 25 to 3.1 µg/mL, while compound 2 displayed activity against all tested fungi except for Rhizoctonia solani and Fusarium oxysporum with MIC values from 50 to 12.5 µg/mL. Furthermore, compounds 1-2 also exhibited significant inhibitory activity against eight of thirteen tested bacteria with MIC values ranging from 50 to 6.3 µg/mL.

Emericellins A and B: Two sesquiterpenoids with an unprecedented tricyclo[4,4,2,1]hendecane scaffold from the liquid cultures of endophytic fungus Emericella sp. XL 029.

Two novel sesquiterpenoids with an unprecedented tricyclo[4,4,2,1]hendecane scaffold, namely emericellins A (1) and B (2) representing a new skeleton, were isolated from the liquid cultures of an endophytic fungus Emericella sp. XL 029 associated with the leaves of Panax notoginseng. Their structures and relative configurations were characterized by extensive spectroscopic methods. Compounds 1-2 displayed moderate activities against three fungal strains (Verticillium dahliae Kleb, Helminthosporium maydis, and Botryosphaeria dothidea) and three bacterial strains (Bacillus subtilis, Bacillus cereus and Escherichia coli) with MIC values of 25-50 µg/mL.

New alkenylated tetrahydropyran derivatives from the marine sediment-derived fungus Westerdykella dispersa and their bioactivities.

Six new alkenylated tetrahydropyran derivatives belonged to polyketides, designated as (12R,13R)-dihydroxylanomycinol (1), (12S,13S)-dihydroxylanomycinol (2), (12R,13S)-dihydroxylanomycinol (3) and (12S,13R)-dihydroxylanomycinol (4), (12S,13R)-N-acetyl-dihydroxylanomycin (5) and (12S,13S)-N-acetyl-dihydroxylanomycin (6), together with one related known compound lanomycinol (7) were isolated from the liquid cultures of Westerdykella dispersa obtained from the marine sediments. Their structures and absolute configurations were determined on the basis of extensive analysis of NMR spectra combined with comparison of NMR data to those of known compound, and computational method via calculation of the electronic circular dichroism (ECD). The anti-agricultural pathogenic fungal and antibacterial activities of all isolated compounds were evaluated. Compounds 1-7 exhibited moderate antifungal activities selectively against tested fungal strains with minimum inhibitory concentration (MIC) values ranging from 12.5 to 50µg/mL, and weak antibacterial activities selectively against tested antibacterial strains with MIC value at 100µg/mL.

Cytochalasan and Tyrosine-Derived Alkaloids from the Marine Sediment-Derived Fungus Westerdykella dispersa and Their Bioactivities.

Six new cytochalasans, designated as 18-oxo-19,20-dihydrophomacin C (1), 18-oxo-19-methoxy-19,20- dihydrophomacin C (2), 18-oxo-19-hydroxyl-19,20-dihydrophomacin C (3), 19,20-dihydrophomacin C (4), 19-methoxy-19,20-dihydrophomacin C (5), 19-hydroxyl-19,20-dihydrophomacin C (6), and one new tyrosine-derived alkaloid named as gymnastatin Z (8), together with two known compounds, phomacin B (7) and triticone D (9), were isolated from a solid-substrate fermentation culture of Westerdykella dispersa which was derived from marine sediments. Their structures were established on the basis of spectroscopic analysis using 1D and 2D NMR techniques, and comparison of NMR data to those of known compounds. The anti-bacterial and cytotoxic activities assays of all isolated compounds were evaluated against eight human pathogenic bacteria and five human cancer cell lines, respectively. Compound 8 exhibited moderate activity against B. subtilis with MIC values of 12.5 µg/mL, while compounds 5, 7 and 8 displayed moderate inhibitory activities against five human cancer cell lines (MCF-7, HepG2, A549, HT-29 and SGC-7901), with IC50 values ranging from 25.6 to 83.7 µM.