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Polystyrene nanoplastics (PS-NPs) are widely used in industry, pharmaceutical and consumer packaging materials, and medical products. The biological health impacts of PS-NPs are receiving increasing attention. Therefore, it is necessary to conduct a literature review of in vitro and in vivo experimental studies from a biological mechanism perspective. Based on the latest research results at home and abroad, this review introduced the characteristics and cell internalization of PS-NPs in cytotoxicity experiments, and summarized the effects of PS-NPs on cytotoxic targets such as mitochondria, lysosomes, proteins, and DNA. In addition, the influencing factors of the health effects of PS-NPs were analyzed from the aspects of physical and chemical properties and cell types. Finally, by discussing the current research hotspots of cytotoxicity mechanism and biological effects, it was anticipated to provide a reference for the health risk management and biological safety assessment of PS-NPs.
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Objective To construct the prokaryotic expression vector pET30a( +)-VH-mms13 and identification of its protein after induced with IPTG.Method Heavy chain variable region VH gene of typeⅣcollagenase monoclonal antibody and magnetosome membrane protein gene mms13 were amplified separately,the fusion gene VH-linker-mms13 were synthesized by SOE-PCR technique and inserted into pET30a ( +) plasmid, which was confirmed by restriction enzyme digest and sequencing.Then the recombinant plasmid pET30a ( +)-VH-mms13 was transform into E.coli DE3 and induced with 0.4 mmol/L IPTG.The fused protein was identified by SDS-PAGE and Western blot.Results The length of fusion gene VH-mms13 was 738 bp,and the sequence was correct.After induced with IPTG,the fused protein was found in the inclusion body and Western blot results suggested that the fused protein can bind with His-tag antibody specifically.Conclusion Expression vector pET30a ( +)-VH-mms13 is successfully constructed and the fusion protein has good immunogenicity,which lay the foundation for the development of biomagnetism-targeted drug.
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In order to adapt to the requirements of modem medical knowledge and skills for higher medical workers,and to cultivate medical students' molecular medicine quality and comprehensive ability,Weifang Medical University broke the boundaries of disciplines and constructed experimental course group in molecular medicine based on the ideas of curriculum group construction.Molecular medical knowledge was integrated into the teaching process of experimental course group,experimental teaching content system was reasonably integrated and optimized,high quality teaching team was set up,multi-level experimental teaching platform was built and student-centered teaching mode was implemented to explore the experimental teaching approach which helped medical students to form systematic molecular medicine knowledge structure and ability structure.
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<p><b>OBJECTIVE</b>To label embryonic stem (ES) cells with enhanced green fluorescent protein (EGFP) on the hypoxanthineguanine phosphoribosyl transferase (HPRT) gene locus for the first time to provide a convenient and efficient way for cell tracking and manipulation in the studies of transplantation and stem cell therapy.</p><p><b>METHODS</b>Homologous fragments were obtained by polymerase chain reaction (PCR), from which the gene targeting vector pHPRT-EGFP was constructed. The linearized vector was introduced into ES cells by electroporation. The G418(r)6TG(r) cell clones were obtained after selection with G418 and 6TG media. The integration patterns of these resistant cell clones were identified with Southern blotting.</p><p><b>RESULTS</b>EGFP expressing ES cells on the locus of HPRT were successfully generated. They have normal properties, such as karyotype, viability and differentiation ability. The green fluorescence of EGFP expressing cells was maintained in propagation of the ES cells for more than 30 passages and in differentiated cells. Cultured in suspension, the "green" ES cells aggregated and formed embryoid bodies, retaining the green fluorescence at varying developmental stages. The "green" embryoid bodies could expand and differentiate into various types of cells, exhibiting ubiquitous green fluorescence.</p><p><b>CONCLUSIONS</b>This generation of "green" targeted ES cells is described in an efficient protocol for obtaining the homologous fragments by PCR. Introducing the marker gene in the genome of ES cells, we should be able to manipulate them in vitro and use them as vehicles in cell-replacement therapy as well as for other biomedical and research purposes.</p>