Cloning, expression, and spectral analysis of mouse betatrophin.

Background: Betatrophin, a novel secretory protein from liver and fatty tissues, is believed to be involved in lipid and glucose metabolism. However, its precise physiological role remains unclear. Here, we report the cloning, expression, and purification steps of mouse betatrophin in a prokaryotic system, followed by its structural analysis. Methods: Specific cloning primers were used to amplify the coding sequence of mouse liver betatrophin. The product was cloned into pET28 and expressed in E.coli BL21 (DE3) cells. The suitability of the refolding procedure was assessed by determining secondary structures of the initial and refolded proteins using circular dichroism spectroscopy. Results: The polymerase chain reaction resulted in a 549 bp nucleotide sequence, encoding a 183 amino acid polypeptide, with an apparent molecular weight of 21 kDa, which was expressed in an inclusion body. Following an optimization and refolding procedure, the recombinant protein was purified by anion exchange and metal affinity chromatography. CD spectra revealed that the refolded protein has suitable configuration. Conclusion: We believe that the produced betatrophin is suitable for further biochemical studies on glucose and lipid metabolism.

Perceived challenges and barriers for medical students in the COVID-19 crisis.

BACKGROUND: Unpredictable and immediate changes, especially in the clinical and practical fields of medical sciences following the coronavirus disease (COVID-19) epidemic, have posed many challenges for medical students. This study was conducted to identify the experiences and students' understanding of the challenges in the COVID-19 crisis. MATERIALS AND METHODS: The present qualitative research was conducted by performing semi-structured interviews with the students along with holding a student panel. The study population consisted of 30 clinical and basic medical students of Babol, Iran and Kermanshah universities of medical sciences who were selected by purposive sampling method. Data were collected based on students' perceived experiences of challenges, obstacles, and problems in the COVID-19 crisis. The data analysis process was performed by conducting interviews and information obtained from the panel using v10 R150410 software. Finally, the related factors and components were identified. RESULTS: Challenges and perceived obstacles of medical students in the COVID-19 crisis were identified in the form of eight factors including student life factors, interaction and communication, psychological factors, educational technology, factors related to the professors, limitations of educational and research planning, crisis management, and educational evaluation. CONCLUSION: Identifying the challenges of medical education perceived by students in this study and adopting appropriate strategies to overcome existing barriers open new opportunities for expanding the scope of the curriculum, providing education, and promoting community health to universities; moreover, the challenges of medical education and any skill-based discipline, such as medical sciences in the COVID-19 pandemic will require much attention and investigation in cognitive sciences.

Oyster Saccostrea cucullata as a biomonitor for Hg contamination and the risk to humans on the coast of Qeshm Island, Persian Gulf, Iran.

A total of 174 individuals of rocky oysters (Saccostrea cucullata) and 35 surface sediment samples were collected from seven stations off the intertidal zones of Qeshm Island, Persian Gulf, in order to study the concentration of mercury in oysters' tissues, and to investigate whether mercury concentrations in the edible soft tissues are within the permissible limits for public health. The average mercury concentrations were found as 3.44, 50.66 and 2.29 µg kg(-1) dw in the sediments, soft tissues and shells of the oysters, respectively. Results indicated that the levels of mercury in sediment differed significantly between the stations. In addition, results confirmed that the soft tissues of oysters could be a good indicator of mercury in the aquatic system. In comparison with food safety standards, mercury levels in oysters were well within the permissible limits for human consumption.

Identification and Characterization of Main Allergic Proteins in Cooked Wolf Herring Fish.

Our aim in this study was to identify and characterize allergic proteins in cooked wolf herring fish. We heated the crude extract alternatively at 50, 60, 70, 80, 90, and 100°C for one hour and results were compared by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Also, proteins were immunoblotted with fish-sensitive patients' sera. The major allergenic proteins were identified via mass spectrometry. These allergenic proteins were then purified by anion exchange chromatography and the IgE-immunoreactivity of the fractions was compared with the crude extracts via disk enzyme-linked immunosorbent assay (ELISA). SDS-PAGE of the crude extract showed more than 15 distinct protein bands. Five of these proteins, with apparent molecular weights of 12, 18, 24, 38, and 51 kDa, were only observed in the 100°C heated extract. Immunoblotting of the heated extract revealed that the 12 and 51 kDa proteins were IgE-immunoreactive with 88 percent of fish-sensitive patient sera while the 24 and 38 kDa proteins reacted with 33.3 and 55.5 percent of fish-sensitive patient sera, respectively. Mass spectrometry of the 12, 38, and 51 kDa proteins revealed that all three were parvalbumin oligomers. Disk ELISA results showed that 20 of 25 and 14 of 25 fish-allergic patients' sera were IgE-reactive with purified oligomeric parvalbumin-coated and crude extract-coated disks, respectively. Parvalbumin and its oligomers are the main allergenic molecules in cooked fish. Therefore, an enriched or purified fraction containing this protein could be a useful source of allergen for applications in ELISA-based immunoassays and could discriminate fish-allergic patients who can tolerate cooked fish from those who cannot.