Publications by authors named "Xia Li-Qiu"

Inspired by information processing and communication in nature based on molecular recognition and structural diversity, ongoing efforts aim to development of artificial molecular or nano-systems for sensing, logic computing, and even data storage and safety. However, due to their preparation/functionalization shortcomings (laborious and time-consuming), poor flexibility and compatibility, and limited paradigm, it is still a big challenge whether simple molecules can be used to achieve comprehensive and universal applications from sensing to information storage and protection. Herein, we for the first time demonstrated a molecular paradigm-computer-like "basic input output system (BIOS)" which can realize "plug-and-play" sensing, information encoding, molecular cryptography, and steganography based on a simple artificial molecule (p-nitrophenol, PNP).

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Plasmonic materials have been widely used in chemo/biosensing and biomedicine. However, little attention has been paid to the application of plasmonic materials in terms of the transition from molecular sensing to molecular informatization. Herein, we demonstrated that silver nanoparticles (AgNPs) prepared through facile and rapid microwave heating have multimode colorimetric sensing capabilities to different metal ions (Cr, Hg, and Ni), which can be further transformed into interesting and powerful molecular information technology (massively parallel molecular logic computing and molecular information protection).

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Tumorigenesis, metastasis, and the recurrence of cancer, which may result from the abnormal presence or activation of cancer stem cells (CSCs), are involved in disorders of exchanged matter (biomarkers), energy and information in living organisms. Rapid and sensitive detection and imaging of CSC biomarkers (such as CD133) are helpful for early diagnosis and therapeutic evaluation of tumors. Recently, a preliminary exploration of a few affinity molecules (like peptide-based probes) has just begun for chemical measurements and imaging of CSC biomarker CD133.

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Inspired by information processing and communication of life based on complex molecular interactions, some artificial (bio)chemical systems have been developed for applications in molecular information processing or chemo/biosensing and imaging. However, little attention has been paid to simultaneously and comprehensively utilize the information computing, encoding, and molecular recognition capabilities of molecular-level systems (such as DNA-based systems) for multifunctional applications. Herein, a graphene-based steganographically aptasensing system was constructed for multifunctional application, which relies on specific molecular recognition and information encoding abilities of DNA aptamers ( Aeromonas hydrophila and Edwardsiella tarda-binding aptamers as models) and the selective adsorption and fluorescence quenching capacities of graphene oxide (GO).

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Sensing of pyrophosphate (PPi) is helpful to better understand many life processes and diagnose various early-stage diseases. However, many traditional reported methods based on artificial receptors for sensing of PPi exhibit some disadvantages including difficulties in designing appropriate binding sites and complicated multi-step assembly/functionalization. Thus, it is significantly important and a big challenge to know how to use a simple molecular self-assembly or an interaction system to solve the above-mentioned limits to achieve the quantitative analysis of specific substances in the system.

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Due to rapid change in information technology, many consumer electronics become electronic waste which is the fastest-growing pollution problems worldwide. In fact, many discarded electronics with prefabricated micro/nanostructures may provide a good basis to fulfill special needs of other fields, such as tissue engineering, biosensors, and energy. Herein, to take waste optical discs as an example, we demonstrate that discarded electronics can be directly repurposed as highly anisotropic platforms for in vitro investigation of cell behaviors, such as cell adhesion, cell alignment, and cell-cell interactions.

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Patterning graphene allows to precisely tune its properties to manufacture flexible functional materials or miniaturized devices for electronic and biomedical applications. However, conventional lithographic techniques are cumbersome for scalable production of time- and cost-effective graphene patterns, thus greatly impeding their practical applications. Here, we present a simple scalable fabrication of wafer-scale three-dimensional (3D) graphene micropatterns by direct laser tuning graphene oxide reduction and expansion using a LightScribe DVD writer.

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The most serious and yet unsolved problems of molecular logic computing consist in how to connect molecular events in complex systems into a usable device with specific functions and how to selectively control branchy logic processes from the cascading logic systems. This report demonstrates that a Boolean logic tree is utilized to organize and connect "plug and play" chemical events DNA, nanomaterials, organic dye, biomolecule, and denaturant for developing the dual-signal electrochemical evolution aptasensor system with good resettability for amplification detection of thrombin, controllable and selectable three-state logic computation, and keypad lock security operation. The aptasensor system combines the merits of DNA-functionalized nanoamplification architecture and simple dual-signal electroactive dye brilliant cresyl blue for sensitive and selective detection of thrombin with a wide linear response range of 0.

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Objective: To investigate the flexibility and mobility of the Bacillus thuringiensis toxin Cry1Aa.

Methods: The graph theory-based program Constraint Network Analysis and normal mode-based program NMsim were used to analyze the global and local flexibility indices as well as the fluctuation of individual residues in detail.

Results: The decrease in Cry1Aa network rigidity with the increase of temperature was evident.

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A unique residue W544 in the beta18-beta19 loop of the Bacillus thuringiensis Cry1Ac toxin has been implicated in its toxicity. In this study, the effects of mutations at this residue on protein stability during protease treatment, UV irradiation, and preservation were examined. Residue 544 of Cry1Ac was involved in maintaining structural stability, and substitution of a polar group at this position was unfavorable to protein stability.

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Our previous mutagenic analysis showed that the unique residue N546 in the apex of beta18-beta19 loop of Bacillus thuringiensis Cry1Ac toxin is important for its toxicity. In this study, trypsin digestion susceptibility, binding to BBMV and oligomer formation activity was therefore analyzed to determine the mechanism of toxicity change of these mutant toxins. The results showed that residue N546 was not involved in toxin oligomerisation and maintaining the stability of toxin, the enhanced toxicity of mutant N546A was just because of increased binding to BBMV, and reduction in toxicity of other mutants were caused by reduction in initial or irreversible binding to BBMV.

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Cry5Aa is a crystal protein produced by Bacillus thuringiensis serovar. damstadiensis during its stationary phase, this delta-endotoxin is active against nematodes and has great potential for nematodes control. The theoretical model of the three-dimensional structure of Cry5Aa was predicted by homology modeling on the structures of the Cry1Aa which is specific to Lepidopteran insects.

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A fusion gene was constructed by combining the cry1Ac gene of Bacillus thuringiensis strain 4.0718 with a neurotoxin gene, hwtx-1, which was synthesized chemically. In this process, an enterokinase recognition site sequence was inserted in frame between two genes, and the fusion gene, including the promoter and the terminator of the cry1Ac gene, was cloned into the shuttle vector pHT304 to obtain a new expression vector, pXL43.

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Cry5Ba is a delta-endotoxin produced by Bacillus thuringiensis PS86A1 NRRL B-18900. It is active against nematodes and has great potential for nematode control. Here, we predict the first theoretical model of the three-dimensional (3D) structure of a Cry5Ba toxin by homology modeling on the structure of the Cry1Aa toxin, which is specific to Lepidopteran insects.

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Article Synopsis
  • A new fusion gene cry1Ac-tchiB was developed by combining the cry1Ac gene from Bacillus thuringiensis with a modified tchiB gene, aiming to boost the toxicity of crystal proteins.
  • Through a series of cloning and transformation steps involving the creation of two new expression vectors, recombinant bacterial strains HAccB6 and HAccB7 were produced, which showed significant expression of the fusion protein.
  • The results demonstrated that these recombinant strains generated proteins with higher toxicity against larvae, outperforming the original Cry1Ac protein, which suggests potential for developing more toxic strains for pest control.
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The present study analyses the insecticidal crystal proteins (ICPs) from Bacillus thuringiensis strain 4.0718 through two-dimensional electrophoresis and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS). By comparing and optimizing the composition of lysis solution, the volume of sample loading and the protocol for isoelectric focusing, a well-focused 2-DE map with high resolution and reproducibility was achieved for the first time.

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Article Synopsis
  • The CrylA crystal protein from Bacillus thuringiensis is linked to unknown DNA sequences, which were studied by extracting and analyzing associated DNA from bipyramidal crystals.
  • Using specific enzymes and cloning techniques, researchers created recombinant plasmids containing amplified cry1Ac gene fragments and produced high amounts of a fusion protein, which was confirmed to be a significant part of the cellular protein composition.
  • Bioassays demonstrated that the inclusion bodies and crystals from the modified strains exhibited high toxicity against the larvae of Plutella xylostella, paving the way for further research into insecticidal applications.
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