Proteases are important enzymes that are engaged in a variety of essential physiological functions and have a significant possible use in industrial applications. In this work, we reported the purification and biochemical characterization of a detergent stable, antimicrobial, and antibiofilm potential protease (SH21) produced by Bacillus siamensis CSB55 isolated from Korean fermented vegetable kimchi. SH21 was purified to obtain homogeneity via ammonium sulfate precipitation (40–80%), Sepharose CL-6B, and Sephadex G-75 column. By analyzing the SDS-PAGE and zymogram, it was determined that the molecular weight was around 25 kDa. The enzyme activity was almost completely inhibited in the presence of PMSF and DFP, which indicated that it was a member of the serine protease family. SH21 showed excellent activity with a broad range of pH and temperature, with its maximum pH of 9.0 and temperature of 55 °C. The enzyme had estimated K_m and V_max values of 0.197 mg/mL and 1.22 × 10³ U/mg, respectively. In addition, it preserved good activity in the presence of different organic solvents, surfactants, and other reagents. This enzyme showed good antimicrobial activity that was evaluated by MIC against several pathogenic bacteria. Furthermore, it exhibited strong antibiofilm activity as determined by MBIC and MBEC assay and degraded the biofilms, which were analyzed by confocal microscopic study. These properties established that SH21 is a potent alkaline protease that can be used in industrial and therapeutic applications.

Global public health is facing a major issue with emerging resistance to antimicrobial agents. Antimicrobial agents that are currently on the market are strong and efficient, but it has not been ruled out that these medications will eventually cause resistance to bacteria. Exploring novel bioactive compounds derived from natural sources is therefore, crucial to meet future demands. The present study evaluated the mode of action of the antimicrobial potential protease enzyme SH21. Protease SH21 exhibited antimicrobial activity, strong heat stability (up to 100 °C), and pH stability (pH 3.0 to 9.0). In terms of mode of action, we found that protease SH21 was able to disrupt the bacterial cell membrane as the results of the nucleotide leakage and cell membrane permeability assay. In addition, we also checked inner membrane permeability by PI uptake assay which suggested that protease SH21 has the ability to enter the bacterial cell membrane. Our results revealed that the antimicrobial protease SH21 might be a promising candidate for treating microbial infections.

Background: Chikungunya is a vector-borne disease, mostly present in tropical and subtropical regions. The virus is spread by Ae. aegypti and Ae. albopictus mosquitos and symptoms include high fever to severe joint pain. Dhaka, Bangladesh, suffered an outbreak of chikungunya in 2017 lasting from April to September. With the goal of reducing cases, social media was at the forefront during this outbreak and educated the public about symptoms, prevention, and control of the virus. Popular web-based sources such as the top dailies in Bangladesh, local news outlets, and Facebook spread awareness of the outbreak. Objective: This study sought to investigate the role of social and mainstream media during the chikungunya epidemic. The study objective was to determine if social media can improve awareness of and practice associated with reducing cases of chikungunya. Methods: We collected chikungunya-related information circulated from the top nine television channels in Dhaka, Bangladesh, airing from 1st April–20th August 2017. All the news published in the top six dailies in Bangladesh were also compiled. The 50 most viewed chikungunya-related Bengali videos were manually coded and analyzed. Other social media outlets, such as Facebook, were also analyzed to determine the number of chikungunya-related posts and responses to these posts. Results: Our study showed that media outlets were associated with reducing cases of chikungunya, indicating that media has the potential to impact future outbreaks of these alpha viruses. Each media outlet (e.g., web, television) had an impact on the human response to an individual’s healthcare during this outbreak. Conclusions: To prevent future outbreaks of chikungunya, media outlets and social media can be used to educate the public regarding prevention strategies such as encouraging safe travel, removing stagnant water sources, and assisting with tracking cases globally to determine where future outbreaks may occur.