Publications by authors named "Lan-lan Xu"

Protein reagents are essential resources for several stages of drug discovery projects from structural biology and assay development through lead optimization. Depending on the aim of the project different amounts of pure protein are required. Small-scale expressions are initially used to determine the reachable levels of production and quality before scaling up protein reagent supply.

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Article Synopsis
  • * Researchers analyzed over 100 SARS-CoV-2 protein representations and selected three key antigens from the spike glycoprotein and nucleocapsid protein for further testing on samples from COVID-19 patients and uninfected controls.
  • * The final assay achieved impressive accuracy, with sensitivities ranging from 99.1% to 99.7% and specificities from 95.7% to 100%, especially when using two antigens together, demonstrating the assay's potential for reliable COVID-19 detection.
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The proteins secreted by human tissues and blood cells, the secretome, are important both for the basic understanding of human biology and for identification of potential targets for future diagnosis and therapy. Here, a high-throughput mammalian cell factory is presented that was established to create a resource of recombinant full-length proteins covering the majority of those annotated as 'secreted' in humans. The full-length DNA sequences of each of the predicted secreted proteins were generated by gene synthesis, the constructs were transfected into Chinese hamster ovary (CHO) cells and the recombinant proteins were produced, purified and analyzed.

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A systematic chemical exploration of the marine-derived fungus led to the isolation of four indole-diterpenoid derivatives (-), including new penijanthines C and D ( and ), and a pair of new steroidal epimers, penijanthoids A and B ( and ). The calculated ECD spectra and Snatzke's method for the new compound were carried out to determine its absolute configuration. The absolute configuration of was established by X-ray diffraction and calculated ECD methods for the first time.

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Penicimutanolones A (1) and B (2), penicimutanolone A methyl ether (3), and penicimumide (4), four new antitumor metabolites, were isolated from a neomycin-resistant mutant of the marine-derived fungus Penicillium purpurogenum G59. The structures of the compounds were elucidated by spectroscopic methods, and the absolute configurations were determined by X-ray crystallography and calculated ECD. In MTT and SRB assays, compounds 1-3 showed strong inhibitory effects on 14 human cancer cell lines.

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It is important to design a nice electrochemiluminescence (ECL) biological nanomaterial for fabricating sensitive ECL immunosensor to detect tumor markers. Most reported ECL nanomaterial was decorated by a number of mono-luminophore. Here, we report a novel ECL nanomaterial assembled by dual luminophores perylenetetracarboxylic acid (PTCA) and carbon quantum dots (CQDs).

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Interface states can always arise in heterostructures that consist of two or more (artificial) materials with topologically different energy bands. The gapped band structure can be classified by the Chern number (a topological invariant) generally or the Zak phase in one-dimensional periodic systems. Recently, topological properties have been employed to investigate the interface states occurring at the connecting regions of the heterostructures of mechanical isostatic lattices and acoustical waveguides.

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A new phenyl ether derivative, 3-hydroxy-5-(3-hydroxy-5-methylphenoxy)-4-methoxybenzoic acid (1), along with two known analogues, 3,4-dihydroxy-5-(3-hydroxy-5-methylphenoxy)benzoic acid (2) and 3-hydroxy-5-(3-hydroxy-5-methylphenoxy)benzoic acid (3), were isolated from the fungus Aspergillus carneus collected from South China Sea. The structure elucidation of 1 was determined based on extensive NMR and MS spectroscopic analyses. Compound 2 showed a strong antioxidant activity with an IC value of 19.

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Background: The role of PCT (procalcitonin) in elderly patients with bacterial infection has not fully been investigated. In previous studies, the role of PCT in diagnosing bacterial infection has mainly been studied in patients with severe infections. This study was to access a diagnostic value of PCT in elderly patients with local infection.

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The Raman spectra of 2,6-pyridine dicarboxylic acid (DPA) and their calcium salts(Ca-DPA) in different states and the Ca-DPA in a single bacterial spore have been recorded by laser tweezers Raman system (LTRS) and the spectra have been assigned. Raman spectra of different states of DPA and Ca-DPA are different evidently. Analysis leading to differences in the structure of spectrum may be due to that the Raman spectra of DPA crystalline reflected more precise characteristics information compared to DPA powder, in which the laser can penetrate through DPA crystalline and the Raman scatter from the crystalline interior is greater than that from DPA powder.

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Measuring the levels of 2,6-pyridine dicarboxylic acid (DPA) in bacteria spores could provide the information about the DPA function, resistance mechanism and the mechanism of spore germination. The authors have measured levels of Ca-DPA of individual spores of different 19 kinds of Bacillus which from different sources, species, and strains by using laser tweezers Raman spectroscopy (LTRS). Also we have verified the reproducibility of the system simultaneously.

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Objective: To develog an HPLC method determination of two new saponins in the dried rhizomes of Tupistra chinensis.

Method: The analysis was performed on YMC-Pack ODS-AQ (4.6 mm x 250 mm, 5 microm) eluted with of acetonitrile and waterin gradient mode.

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The demand for high-throughput recombinant protein production has markedly increased with the increased activity in the field of proteomics. Within the Human Protein Atlas project recombinantly produced human protein fragments are used for antibody production. Here we describe how the protein expression and purification protocol has been optimized in the project to allow for handling of nearly 300 different proteins per week.

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Two furostanol saponins were obtained from the rhizomes of Tupistra chinensis Bak. Their structures were determined as 5beta-furost-delta(25(27))-en-1beta,2beta,3beta,4beta,5beta,7alpha,22xi,26-octaol-6-one-26-O-beta-D-glucopyranoside (1) and 5beta-furost-delta(25(27))-en-1beta,2beta,3beta,4beta,5beta,6beta,7alpha,22xi,26-nonaol-26-O-beta-D-glucopyranoside (2), on the basis of chemical and spectroscopic evidence. Both compounds displayed marked inhibitory action against NO production in rat abdomen macrophages induced by lipopolysaccharide (LPS) at 40 microg/mL.

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Antibody-based proteomics provides a powerful approach for the functional study of the human proteome involving the systematic generation of protein-specific affinity reagents. We used this strategy to construct a comprehensive, antibody-based protein atlas for expression and localization profiles in 48 normal human tissues and 20 different cancers. Here we report a new publicly available database containing, in the first version, approximately 400,000 high resolution images corresponding to more than 700 antibodies toward human proteins.

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