• KDI Journal of Economic Policy
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• v.14 no.4
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• pp.107-121
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• 1992

Moonlighting or second-jobs will increase shirking of the primary job. This paper analyzes the motives for moonlighting so that the means of reducing these motives could be explored. The traditional theory claims that a worker who cannot fully realize his work potential will look to moonlighting. In a two-period model, however, the following motives are more important. The precautionary savings motive : A worker has an incentive to save for fear of losing his job and his income in the second period. The worker could save more by working more during the first period, and this additional motive for working is the precautionary savings motive. The insurance motive : When a worker is unemployed, he cannot expand his moonlighting hours according to his needs since the moonlighting hour is upward rigid. Therefore, a worker has an incentive to secure additional moonlighting hours in the first period so that quick adjustment can be made during the unemployment in the second period. Two policy measures to remove those motives for moonlighting are recommended, for these measures will enhance the productivity in the primary job. First, a firm should guarantee that there will be no layoffs in a downturn in the economy and that the employment level is adjusted to the economic states by work sharing among workers. Second, as unemployment insurance benefits compensate a portion of the income in case of unemployment, it substitutes the motives for moonlighting. A generalization of this argument can be found in Ehrlich and Becker(1972) where self-insurance(moonlighting) and market insurance(in this case, unemployment insurance) serves as substitutes. The two policy measures in the above have a spill-over effect : A decrease of labor supply in the moonlighting market will ease job search, and therefore will help those who have their primary job in the moonlighting sector.

• Journal of Labour Economics
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• v.40 no.2
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• pp.31-68
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• 2017

This study examined the moonlighting behavior in Korea, to which relatively less attention has been paid. Based on the wage earners of 25 to 65 year old married, the results show that about 1.4% of the sample have dual jobs, working very long hours, on average 60 hours for a week combining both the primary job and the secondary job. The results of the fixed effects logit model on the moonlighting participation indicate that the wage rate and the hours of work in the primary job have a negative effect on moonlighting participation while the insecurity of the primary job appears to lead to a higher probability of taking a secondary job. The results of the moonlighting hours analysis suggest that hours worked in the primary job have a negative effect on moonlight hours while the wage of the primary job does not appear to have any significant effect on moonlighting hours. Interestingly enough, the wage of the secondary job appears to have a negative impact on moonlighting hours, which might be very plausible considering the long working hours moonlighters are engaged in.

• IMMUNE NETWORK
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• v.23 no.4
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• pp.31.1-31.18
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• 2023

Evidence suggests that the human respiratory tract, as with the gastrointestinal tract, has evolved to its current state in association with commensal microbes. However, little is known about how the airway microbiome affects the development of airway immune system. Here, we uncover a previously unidentified mode of interaction between host airway immunity and a unique strain (AIT01) of Staphylococcus epidermidis, a predominant species of the nasal microbiome. Intranasal administration of AIT01 increased the population of neutrophils and monocytes in mouse lungs. The recruitment of these immune cells resulted in the protection of the murine host against infection by Pseudomonas aeruginosa, a pathogenic bacterium. Interestingly, an AIT01-secreted protein identified as GAPDH, a well-known bacterial moonlighting protein, mediated this protective effect. Intranasal delivery of the purified GAPDH conferred significant resistance against other Gram-negative pathogens (Klebsiella pneumoniae and Acinetobacter baumannii) and influenza A virus. Our findings demonstrate the potential of a native nasal microbe and its secretory protein to enhance innate immune defense against airway infections. These results offer a promising preventive measure, particularly relevant in the context of global pandemics.

• Journal of Veterinary Science
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• v.24 no.5
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• pp.72.1-72.16
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• 2023

Background: Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) on the surface of Streptococcus dysgalactiae, coded with gapC, is a glycolytic enzyme that was reported to be a moonlighting protein and virulence factor. Objective: This study assessed GAPDH as a potential immunization candidate protein to prevent streptococcus infections. Methods: Mice were vaccinated subcutaneously with recombinant GAPDH and challenged with S. dysgalactiae in vivo. They were then evaluated using histological methods. rGAPDH of mouse bone marrow-derived dendritic cells (BMDCs) was evaluated using immunoblotting, reverse transcription quantitative polymerase chain reaction, and enzyme-linked immunosorbent assay methods. Results: Vaccination with rGAPDH improved the survival rates and decreased the bacterial burdens in the mammary glands compared to the control group. The mechanism by which rGAPDH vaccination protects against S. dysgalactiae was investigated. In vitro experiments showed that rGAPDH boosted the generation of interleukin-10 and tumor necrosis factor-α. Treatment of BMDCs with TAK-242, a toll-like receptor 4 inhibitor, or C29, a toll-like receptor 2 inhibitor, reduced cytokines substantially, suggesting that rGAPDH may be a potential ligand for both TLR2 and TLR4. Subsequent investigations showed that rGAPDH may activate the phosphorylation of MAPKs and nuclear factor-κB. Conclusions: GAPDH is a promising immunization candidate protein for targeting virulence and enhancing immune-mediated protection. Further investigations are warranted to understand the mechanisms underlying the activation of BMDCs by rGAPDH in a TLR2- and TLR4-dependent manner and the regulation of inflammatory cytokines contributing to mastitis pathogenesis.