Professor Yonggyum Kim

The seminar also will be on Zoom. The Zoom link:
https://ucdavis.zoom.us/j/94350897170.

Kim is a professor with the Department of Plant Medicals, Andong National University, Andong, Korea, and editor-in-chief of the Archives of Insect Biochemistry and Physiology.

His abstract: "EpOMEs, produced from linoleic acid by CPP450, play a crucial role in terminating excessive and unnecessary immune responses at late infection stage in insects. Alternatively, any increase of EpOME level can enhance the virulence of insect pathogens against insect pests.

"This study tested this hypothesis using a specific inhibitor against soluble epoxide hydrolase (sEH) that degrades EpOMEs, yielding elevated endogenous levels of EpOME. as well as a baculovirus, Autographa californica multiple nucleopolyhedrovirus (AcMNPV), to infect three different lepidopteran insects by either oral feeding or hemocoelic injection treatments.

"The viral infection quickly (within 1 h) induced the expressions of three phospholipase A2 (PLA2) genes and later (after 12 h) up-regulated the expressions of CYP and sEH genes in Spodopera exigua. As expected, the viral virulence was suppressed by the addition of arachidonic acid (a product of PLA2) but enhanced by the addition of either of EpOME regioisomers. In addition, the treatment with the sEH inhibitor (= AUDA) increased the viral virulence against three different lepidopteran insects. This enhanced effect of EpOMEs on viral virulence was further supported by using RNA interference (RNAi): a RNAi specific to CYP expression decreased the viral virulence while a RNAi against sEH expression significantly enhanced the viral virulence. In response to AcMNPV infection, S. exigua larvae exhibited an apoptosis in the midgut, fat body, and epidermis. Inhibition of apoptosis by a pan-caspase inhibitor, Z-VAD-FMK, significantly increased the viral virulence. Similarly, the addition of AUDA to the viral treatment suppressed the gene expressions of the five inducible caspases and cytochrome C to suppress the apoptosis, which led to significant increase of the viral titers in the tissues. These results indicate that EpOMEs play a role in resolving inflammation from viral infection at late stage by down-regulating antiviral apoptosis in the lepidopteran insects."

For more information, contact UC Davis distinguished professor Bruce Hammock at hammocklab-office@ucdavis.edu, Hammock holds a joint appointment with the UC Davis Department of Entomology and Nematology and the UC Davis Comprehensive Cancer Center.