A laboratory exercise for visible gel filtration chromatography using fluorescent proteins

Demonstrating core molecular biology principles using GST-GFP in a semester-long laboratory course

Undergraduate laboratory courses are essential to teaching core principles in STEM. This course, Quantitative Biological Methods, provides a unique approach to teaching molecular biology research techniques to students, in a laboratory that is delivered in a sequence that parallels standard biomedical research laboratory protocols. Students attend a lecture where they are taught the essential principles of biomedical research, and a lab where they learn to use laboratory equipment, perform experiments, and purify and quantify DNA and proteins. The course begins with an introduction to laboratory safety, pipetting, centrifugation, spectrophotometry, and other basic laboratory techniques. Next, the lab focuses on the purification and analysis of glutathione S-transferase (GST) fused to green fluorescent protein (GFP) from an Escherichia coli lysate. Students study this GST-GFP fusion protein and perform protein quantification, enzyme assays, chromatography, fluorescent detection, normalization, SDS-PAGE, and western blotting. Students then learn recombinant DNA technology using the GST-GFP vector that was the source of the fusion protein in the prior labs, and perform ligation, transformation of E. coli cells, blue/white screening, DNA purification via a miniprep, PCR, DNA quantification, restriction enzyme digestion, and agarose gel electrophoresis. Students write laboratory reports to demonstrate an understanding of the principles of the laboratory methods, and they must present and critically analyze their data. The lab methods described herein aim to emphasize the core molecular biology principles and techniques, prepare students for work in a biomedical research laboratory, and introduce students to both GST and GFP, two versatile laboratory proteins.

Anti-diarrhea effects and identification of Musca domestica larvae low molecular weight peptides (LMWP)

Musca domestica larvae have been used clinically to cure children malnutritional stagnation and low molecular weight peptides (LMWP) of Musca domestica larvae showed more useful bioactivities. But there is no report on anti-diarrhea effects and identification of the LWMP. The purposes of this study were clarifying the anti-diarrhea effects by regulating intestinal microecology and identification of LMWP. In anti-diarrhea test, diarrhea mice were administered LMWP by oral gavage. Then rectal stool indicator bacteria were counted also the identification of rectal stool bacteria were determined by PCR-DGGE. In LMWP identification test, GFC and RP-HPLC were used to separate the peptide. Then the single polypeptide was tested by MALDI TOF and N-terminal sequence analysis. The results of anti-diarrhea showed that LMWP was effective in the inhibition diarrhea in mice. And microbial diversity indices showed that LMWP treatment group exhibited a higher number of bands. The identification test showed that LMWP had four main components (10-30KD, S1, S2, S3), and there were 5, 7 and 4 peaks in S1, S2 and S3, respectively. The the molecular weight of S2-5, S3-2 and S3-3 was 877.053D, 877.0631D and 1069.4391D, respectively. And S3-3 was determined as Chain A, Carboxypeptidase G2. So the hypothesis that intestinal microbiological regulation might be one of the potential anti-diarrhea mechanisms of Musca domestica larvae LMWP which had four main components and one of the single polypeptide was identified could be drawn.