Chromatographic purification of the plasmin-like enzyme from clamworm (Perinereis aibuhitensis Grub) and its fibrinolytic activity by metal ions.

In this study, fibrinolytic protease was isolated and purified from Perinereis aibuhitensis Grub, and the extraction process was optimized. The properties of the enzyme, such as the amino acid composition, thermal stability, optimal temperature, and pH, were investigated. After detoxification, proteins collected from fresh Clamworm (Perinereis aibuhitensis Grub) were concentrated via ammonium sulfate precipitation. The crude protease was purified using gel filtration resin (Sephadex G-100), anion exchange resin (DEAE-Sepharose FF), and hydrophobic resin (Phenyl Sepharose 6FF). The molecular weight of the protease was determined by polyacrylamide gel electrophoresis (SDS-PAGE). The optimum temperature and optimum pH of the protease were determined. The activity of crude protease in the 40-60% salt-out section was the highest, reaching 467.53 U/mg. The optimal process for purifying crude protein involved the application of DEAE-Sepharose FF and Phenyl Sepharose 6FF, which resulted in the isolation of a single protease known as Asp60-D1-P1 with the highest fibrinolytic activity; additionally, the enzyme activity was measured at 3367.76 U/mg. Analysis by Native-PAGE and SDS-PAGE revealed that the molecular weight of Asp60-D1-P1 was 44.5 kDa, which consisted of two subunits with molecular weights of 6.5 and 37.8 kDa, respectively. The optimum temperature for Asp60-D1-P1 was 40°C, and the optimal pH was 8.0.

Rapid development and mass production of SARS-CoV-2 neutralizing chicken egg yolk antibodies with protective efficacy in hamsters.

Despite the record speed of developing vaccines and therapeutics against the SARS-CoV-2 virus, it is not a given that such success can be secured in future pandemics. In addition, COVID-19 vaccination and application of therapeutics remain low in developing countries. Rapid and low cost mass production of antiviral IgY antibodies could be an attractive alternative or complementary option for vaccine and therapeutic development. In this article, we rapidly produced SARS-CoV-2 antigens, immunized hens and purified IgY antibodies in 2 months after the SARS-CoV-2 gene sequence became public. We further demonstrated that the IgY antibodies competitively block RBD binding to ACE2, neutralize authentic SARS-CoV-2 virus and effectively protect hamsters from SARS-CoV-2 challenge by preventing weight loss and lung pathology, representing the first comprehensive study with IgY antibodies. The process of mass production can be easily implemented in most developing countries and hence could become a new vital option in our toolbox for combating viral pandemics. This study could stimulate further studies, optimization and potential applications of IgY antibodies as therapeutics and prophylactics for human and animals.

Ginkgo biloba extract alleviates CCl4-induced acute liver injury by regulating PI3K/AKT signaling pathway.

Acute liver injury (ALI) is a global health problem associated with high mortality and has attracted clinical attention. Ginkgo biloba extract (GBE) is an extract from dried Ginkgo leaves that has many pharmacological effects because of its various ingredients and has been shown to be hepatoprotective. We investigated the hepatoprotective effect of GBE on carbon tetrachloride (CCl4)-induced acute liver injury in vitro. The components of Ginkgo biloba extract are analyzed by LC-MS, and the key targets of "liver injury-Ginkgo biloba" are identified based on bioinformatics analysis. The signaling pathways such as PI3K/AKT are mainly enriched with high correlation in KEGG. The results of in vitro experiments showed that compared with the Model group, except that the ALT activity level and MDA content in EGB-L group were not significantly decreased (P > 0.05), the activity of ALT, AST and MDA content in other EGB groups were significantly decreased (P < 0.05), and the activities of SOD and CAT were significantly increased (P < 0.05). The expression of inflammatory factors IL-1ß, IL-6 and TNF-α were also detected. The results showed that compared with the Model group, the contents of IL-6 in EGB-L group were not significantly decreased (P > 0.05), while the contents of IL-1ß, IL-6 and TNF-α in other EGB groups were significantly decreased (P < 0.05), indicating that EGB could reduce the level of cell inflammation. Western blot assay detected the protein expression levels of GF, RTK, PI3K, AKT and p-AKT in cells. The results showed that compared with the Model group, the protein expression levels of GF, RTK, PI3K, AKT and P-AKT were significantly increased after EGB treatment (P < 0.05), and the protein expression level of the EGB-H group was higher than the EGB-L group. Ginkgo biloba extract can inhibit the expression of downstream related genes by activating PI3K/AKT signaling pathway, and at the same time alleviate the inflammatory response of cells, reduce the level of inflammation, and protect the cell damage caused by CCl4.

Rapid, visual and highly sensitive sexing of bovine embryos by recombinase polymerase amplification with CFI staining.

Early bovine embryo sexing both increases the number of offspring of the desired sex, and reduces the subsequent costs of processing unwanted offspring of the opposite sex. The need for cattle of different sexes varies from industry to industry, and a range of tools have been set up to meet this need, but most are energy- and time-consuming, hence it is important to establish a fast and convenient method for bovine embryo determination. Herein, we established a recombinase polymerase amplification (RPA) method combined with CFI dye (RPA-CFI) for sexing of bovine embryos. The assay is highly sensitive, specific, rapid and simple; it can be carried out in only 5 min at 37 °C in a metal bath, and results are visualised using a fluorescent colorimeter. Highly specific male-female common and male-specific primers were designed based on the 1399 bp repeating unit of bovine 1.715 satellite DNA and the male-specific S4 repeating sequence, respectively. The limit of detection (LOD) of RPA-CFI with male-female common primers was 1 pg/µL, and the LOD with male-specific primers was 2 pg/µL. RPA-CFI could determine the sex of bovine embryos from only two cells. This is the first report using RPA-CFI for sex determination of bovine embryos. The assay could be applied to other economically important animals to improve efficiency in livestock industries. Additionally, the assay could relieve pressure on food demand due to human population growth, and contribute to economic development of global stockbreeding.

Screening for diagnostic targets in tuberculosis and study on its pathogenic mechanism based on mRNA sequencing technology and miRNA-mRNA-pathway regulatory network.

Purpose: Tuberculosis is common infectious diseases, characterized by infectivity, concealment and chronicity, and the early diagnosis is helpful to block the spread of tuberculosis and reduce the resistance of Mycobacterium tuberculosis to anti-tuberculosis drugs. At present, there are obvious limitations in the application of clinical detection methods used for the early diagnosis of tuberculosis. RNA sequencing (RNA-Seq) has become an economical and accurate gene sequencing method for quantifying transcripts and detecting unknown RNA species. Methods: A peripheral blood mRNA sequencing was used to screen the differentially expressed genes between healthy people and tuberculosis patients. A protein-protein interaction (PPI) network of differentially expressed genes was constructed through Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) database. The potential diagnostic targets of tuberculosis were screened by the calculation of degree, betweenness and closeness in Cytoscape 3.9.1 software. Finally, the functional pathways and the molecular mechanism of tuberculosis were clarified in combination of the prediction results of key gene miRNAs, and by Gene Ontology (GO) enrichment analysis and the Kyoto Encyclopedia Genes and Genomes (KEGG) pathway annotation analysis. Results: 556 Differential genes of tuberculosis were screened out by mRNA sequencing. Six key genes (AKT1, TP53, EGF, ARF1, CD274 and PRKCZ) were screened as the potential diagnostic targets for tuberculosis by analyzing the PPI regulatory network and using three algorithms. Three pathways related to the pathogenesis of tuberculosis were identified by KEGG pathway analysis, and two key miRNAs (has-miR-150-5p and has-miR-25-3p) that might participate in the pathogenesis of tuberculosis were screened out by constructing a miRNA-mRNA pathway regulatory network. Conclusion: Six key genes and two important miRNAs that could regulate them were screened out by mRNA sequencing. The 6 key genes and 2 important miRNAs may participate in the pathogenesis of infection and invasion of Mycobacterium tuberculosis through herpes simplex virus 1 infection, endocytosis and B cell receptor signaling pathways.

A high-throughput analytical method for multiple DNA targets based on microdroplet PCR coupled with DGGE.

We developed a novel approach to analyze multiple DNA targets based on microdroplet PCR coupled with denaturing gradient gel electrophoresis (MPDG) to achieve high-throughput detection of biological samples. The target DNAs were preamplified using specific primers. Subsequently, the preamplified products were separated into individual microreactors for parallel amplification with high efficiency, avoiding the interference of different primers and templates, and preventing inconsistent amplification efficiency and non-specific amplification. The final products were analyzed using denaturing gradient gel electrophoresis (DGGE). Using genetically modified (GM) maize as samples, the MPDG method could be used for the simultaneous detection of three DNA targets with an absolute limit of detection of 0.5% (w/w), with no cross reaction with other non-GM samples. The simulated sample assay of MPDG suggested that the method is suitable for practical application. The MPDG approach, with high sensitivity and specificity, could play a crucial role in the field of nucleic acid detection.