Enhanced Production of Sisomicin in Micromonospora inyoensis by Protoplast Mutagenesis and Fermentation Optimization.

Sisomicin is a broad-spectrum aminoglycoside antibiotic and is the precursor of netilmicin and plazomicin. However, the fermentation level of sisomicin is still low compared with other antibiotics, which restricts the application of sisomicin and its derivatives. In this study, to improve sisomicin production, breeding of high-yielding sisomicin strains was conducted with chemical mutagenesis using Micromonospora inyoensis OG-1 (titer, 1042 U·mL-1) as the starting strain. Protoplast preparation was conducted under optimal conditions, and protoplast mutagenesis was performed with a suitable concentration of diethyl sulfate. Subsequently, a high-yielding and genetically stable strain (H6-32) was obtained by screening, with a sisomicin titer of 1486 U·mL-1 (an increase of 42.6%). Finally, carbon and nitrogen sources were optimized to further improve sisomicin production, and a sisomicin titer of 1780 U·mL-1 was ultimately obtained by controlling the dissolved oxygen level at 30% in a 5-L fermenter, which to the best of our knowledge is the highest reported titer ever achieved by fermentation. Comparative genome analysis showed that a total of 13 genes in the genome of the mutant strain H6-32 were mutated compared to the original strain. This study not only provides a reference for further breeding of high-yielding strains and fermentation optimization, but also enhances our understanding of sisomicin production.

Examining the Influence of Authentic Leadership on Follower Hope and Organizational Citizenship Behavior: The Mediating Role of Follower Identification.

Authentic leadership's influence on follower outcomes through the mediating roles of identification with the supervisor and social identification forms the core purpose of this research. By studying this less explored relationship within leadership studies, we aim to elucidate how these factors interrelate within the context of follower hope and organizational citizenship behavior (OCB). Using a quantitative methodology, we gathered and analyzed data from a sample of 241 employees across various South Korean businesses. Our main findings reveal that a follower's identification with the supervisor significantly mediates the relationship between perceived authentic leadership and follower outcomes, such as hope and OCB. Concurrently, the study found that strengthening employee identification with their work group positively enhances these outcomes. From these findings, we conclude that authentic leadership can effectively drive follower identification, fostering beneficial outcomes, such as hope and OCB. It also suggests that workplaces that promote authentic leadership and a culture of strong supervisor and social identification can effectively enhance overall employee well-being and organizational performance.

Impact of authentic leadership on employee turnover intention: Perceived supervisor support as mediator and organizational identification as moderator.

Authentic leadership is considered a critical factor for retaining talented employees. However, despite fruitful findings, researchers have paid little attention to how authentic leadership is associated with employee turnover intention. Drawing on organizational support theory, justice literature, and social identity theory, we examine the effects of supervisors' authentic leadership on employee turnover intention to better understand how authentic leaders reduce employees' turnover intention in Asian context. In this study, we focus on the mediating role of perceived supervisor support (PSS) and the moderating role of organizational identification in the relationship between supervisors' authentic leadership and employee turnover intention. To test our hypothesized research model, we adopted a cross-sectional design with a convenience data sampling. We also used a self-report research design in the current study. We collected data from 433 employees from several organizations in Korea. Our respondents rated their immediate supervisors' authentic leadership and their PSS, turnover intention and organizational identification. Confirmatory factor analysis, regression analysis, and moderated mediation analysis revealed that: authentic leadership negatively predicted employee turnover intention. In addition, PSS completely mediates the relationship between authentic leadership and employee turnover intention. Furthermore, organizational identification moderates the relationship between PSS and turnover intention. Lastly, organizational identification moderates the mediating effect of PSS on the relationships between perceptions of authentic leadership and employee turnover intention. Herein, we discuss the managerial implications and future research directions arising from our study.