Expansin is a plant protein family that induces plant cell wall-loosening and cellulose disruption without exerting cellulose-hydrolytic activity. Expansin-like proteins have also been found in other eukaryotes such as nematodes and fungi. While searching for an expansin produced by bacteria, we found that the BsEXLX1 protein from Bacillus subtilis had a structure that was similar to that of a beta-expansin produced by maize. Therefore, we cloned the BsEXLX1 gene and expressed it in Escherichia coli to evaluate its function. When incubated with filter paper as a cellulose substrate, the recombinant protein exhibited both cellulose-binding and cellulose-weakening activities, which are known functions of plant expansins. In addition, evaluation of the enzymatic hydrolysis of filter paper revealed that the recombinant protein also displayed a significant synergism when mixed with cellulase. By comparing the activity of a mixture of cellulase and the bacterial expansin to the additive activity of the individual proteins, the synergistic activity was found to be as high as 240% when filter paper was incubated with cellulase and BsEXLX1, which was 5.7-fold greater than the activity of cellulase alone. However, this synergistic effect was observed when only a low dosage of cellulase was used. This is the first study to characterize the function of an expansin produced by a non-eukaryotic source.

It is important to pay attention to the indirect effects of the social distancing implemented to prevent the spread of coronavirus disease 2019 (COVID-19) pandemic on children and adolescent health. The aim of the present study was to explore impacts of a reduction in physical activity caused by COVID-19 outbreak in pediatric patients diagnosed with obesity. This study conducted between pre-school closing and school closing period and 90 patients aged between 6- and 18-year-old were included. Comparing the variables between pre-school closing period and school closing period in patients suffering from obesity revealed significant differences in variables related to metabolism such as body weight z-score, body mass index z-score, liver enzymes and lipid profile. We further evaluated the metabolic factors related to obesity. When comparing patients with or without nonalcoholic fatty liver disease (NAFLD), only hemoglobin A1c (HbA1c) was the only difference between the two time points (p < 0.05). We found that reduced physical activity due to school closing during COVID-19 pandemic exacerbated obesity among children and adolescents and negatively affects the HbA1C increase in NAFLD patients compared to non-NAFLD patients.

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