Photodynamic Effect of Hypericin on the Conformation and Catalytic Activity of Hemoglobin

Hypericin, extracted from H. perforatum, can induce the generation of reactive oxygen species by visible light irradiation, which may consequently induce the conformational change of hemoglobin. We have not only employed UV-vis spectroscopy to observe the changes of UV-vis spectra of the protein, which reveals the conformational changes of the protein, but also employed electrochemical method to obtain its enhanced peroxidase activity. The photodynamic effect of hypericin on the conformation and catalytic activity of the protein has also been proven to be strongly dependent on the irradiation time, the hypericin concentration and the presence of oxygen. This work is beneficial not only to the fabrication of more sensitive hydrogen peroxide biosensor, but also to the guidance of the usage of this medicinal herb molecule, since the conformational change of the protein and the enhanced peroxidase can be easily obtained only by visible light irradiation on hypericin, the process of which is so common to happen

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Co3O4 nanoparticles were prepared from cobalt nitrate that was accommodated in the pores of a metal-organic framework (MOF) ZIF-8 (Zn(MeIM)2, MeIM = 2-methylimidazole) by using a simple liquid-phase method. Analysis by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that the obtained Co3O4 was composed of separate nanoparticles with a mean size of 30 nm. The obtained Co3O4 nanoparticles exhibited superior electrochemical property. Co3O4 electrode exhibited a maximum specific capacitance of 189.1 F g−1 at the specific current of 0.2 A g−1. Meanwhile, the Co3O4 electrode possessed the high specific capacitance retention ratio at the current density ranging from 0.2 to 1.0 A g−1, thereby indicating that Co3O4 electrode suited high-rate charge/discharge

Self-Catalyzed Assembly of Peptide Scaffolded Nanozyme as a Dynamic Biosensing System

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Electrochemical Detection and Distribution Analysis of β‑Catenin for the Evaluation of Invasion and Metastasis in Hepatocellular Carcinoma

Pro-metastatic cell signaling controls the switch to distant metastasis and the final cancer death. In hepatocellular carcinoma (HCC), this death switch is turned on by the multiprotein interactions of β-catenin with many transcription factors, so a method to assay the bioactivity of β-catenin to participate in these pro-metastatic protein/protein interactions has been proposed in this work. This method employs cost-effective peptide-based protein targeting ligands, while the electrochemical catalytic cross-linking in this method also “finalize” the noncovalent molecular recognition, so that the robustness can be improved to enable detection of relatively more complex biosamples. In studying clinical samples with the proposed method, the cellular distribution and overall expression of β-catenin show a parallel with the pathological grade of the sample, particularly, nuclear translocation. The pro-metastatic activation of β-catenin can also be observed as evidently correlated with higher-grade cases, suggesting the active role of β-catenin in promoting metastasis. According to these results, the proposed method may have the prospective use as a prognostic tool for evaluating the potential of invasion and metastasis in cancer

Assembly of Selective Biomimetic Surface on an Electrode Surface: A Design of Nano–Bio Interface for Biosensing

In nature, cellular molecule sensing is usually achieved at the environment/membrane interface. In the meantime, rapid growth of nanotechnology is increasingly pushing engineered nanomaterials to interact with biological surfaces. Herein, inspired by trans-membrane signal transduction, a nano–bio interface has been constructed in this work for biosensing application. The interface is formed between a selective biomembrane mimetic surface (SBMMS) and a function-oriented 2D nanohybrid. Based on the design, target recognition can be performed in a biologically favorable environment, and the nano–bio interaction can be transduced into amplified electrochemical readouts. Furthermore, this sensing platform can be used to analyze various kinds of targets, including proteins, nucleic acids, and small molecules, just by changing the biorecognition element. Low detection limits and wide detection ranges can also be obtained. So, this nano–bio interface may provide a new platform for bioanalytical research in the future

RNA Sequencing Analysis of Chicken Cecum Tissues Following Eimeria tenella Infection in Vivo

Eimeria tenella (E. tenella) is one of the most frequent and pathogenic species of protozoan parasites of the genus Eimeria that exclusively occupies the cecum, exerting a high economic impact on the poultry industry. To investigate differentially expressed genes (DEGs) in the cecal tissue of Jinghai yellow chickens infected with E. tenella, the molecular response process, and the immune response mechanism during coccidial infection, RNA-seq was used to analyze the cecal tissues of an E. tenella infection group (JS) and an uninfected group (JC) on the seventh day post-infection. The DEGs were screened by functional and pathway enrichment analyses. The results indicated that there were 5477 DEGs (p-value < 0.05) between the JS and the JC groups, of which 2942 were upregulated, and 2535 were downregulated. GO analysis indicated that the top 30 significantly enriched GO terms mainly involved signal transduction, angiogenesis, inflammatory response, and blood vessel development. KEGG analysis revealed that the top significantly enriched signaling pathways included focal adhesion, extracellular matrix–receptor interaction, and peroxisome proliferator-activated receptor. The key DEGs in these pathways included ANGPTL4, ACSL5, VEGFC, MAPK10, and CD44. These genes play an important role in the infection of E. tenella. This study further enhances our understanding of the molecular mechanism of E. tenella infection in chickens

Protein Detection Based on Small Molecule-Linked DNA

Based on small molecule-linked DNA and the nicking endonuclease-assisted amplification (NEA) strategy, a novel electrochemical method for protein detection is proposed in this work. Specifically, the small molecule-linked DNA (probe 1) can be protected from exonuclease-catalyzed digestion upon binding to the protein target of the small molecule, so the DNA strand may hybridize with another DNA strand (probe 2) that is previously immobilized onto an electrode surface. Consequently, the NEA process is triggered, resulting in continuous removal of the DNA strands from the electrode surface, and the blocking effect against the electrochemical species [Fe­(CN)₆]^3–/4– becomes increasingly lower; thus, increased electrochemical waves can be achieved. Because the whole process is activated by the target protein, an electrochemical method for protein quantification is developed. Taking folate receptor (FR) as an example in this work, we can determine the protein in a linear range from 0.3 to 15 ng/mL with a detection limit of 0.19 ng/mL. Furthermore, because the method can be used for the assay of FR in serum samples and for the detection of other proteins such as streptavidin by simply changing the small molecule moiety of the DNA probes, this novel method is expected to have great potential applications in the future

Evaluating Tumor-Associated Activity of Extracellular Sulfatase by Analyzing Naturally Occurring Substrate in Tumor Microenvironment of Hepatocellular Carcinoma

The progress of cancer is intimately connected with the activity of the extracellular matrix (ECM) enzymes. To evaluate the promoting effect of these enzymes on tumor development in a pathological biocontext, we propose in this work to analyze their natural substrates in the ECM. This strategy is demonstrated by studying heparan sulfate (HS), the substrate of ECM sulfatase, in the development of hepatocellular carcinoma (HCC). An assay is designed to study the abundance and sulfation of HS and to evaluate the interactions between HS and the growth factors, such as fibroblast growth factor 2 (FGF2). Peptides derived from the amyloid peptide and various growth factors are employed to detect HS and evaluate their affinity toward the growth factors, whereas the ruthenium polypyridyl complex is taken as a photocatalyst to achieve a more sensitive signal readout. Applying this method to HepG2 cells, correlated changes between the activity of sulfatase 2 in regulating FGF2-induced cell proliferation and the abundance, degree of sulfation, and growth factor binding of HS can be observed. This method has also been applied to analyze clinical tissue samples of HCC. The results may suggest tumor-progress-related alterations in the above-studied biochemical features of HS. These results may point to the prospect of using this method to facilitate the diagnosis and prognosis of HCC in the future