The recombinant protein yields for batch cultures of the insect cell baculovirus expression system have been significantly enhanced by oxygen, glucose, and glutamine feeding. The improvement in both volumetric and specific yields was based on influencing the metabolism of infected cells. Oxygen was absolutely required for viral replication and high protein expression in infected cells. Increases of 200% in volumetric yield and 100% in specific yield of recombinant epoxide hydrolase were achieved by controlling the dissolved oxygen (DO) level to near 35% saturation. An additional 100% increase was achieved by glucose and glutamine feeding. Results indicated that the intracellular metabolite pool was not adequate for recombinant protein overproduction. Finally, the specific protein yield, based on initial infection cell density, in high cell density spinner flasks and bioreactors of spent media with glucose and glutamine feeding was equivalent to that freshly diluted cultures.

Glutamine is an essential nutrient in insect cell culture and plays a role in maximizing protein expression in baculovirus-infected cells. This paper presents a technique which combines two enzymatic reactions, specifically the deamination of glutamine via glutaminase and the subsequent amination of 2-oxoglutarate to glutamate, to measure the concentration of glutamine in insect cell media. A specific ghttamine uptake rate of 4.2x lo-* umol/lO%ells/hr was determined for infected cells by this method.

Previous studies have suggested that the dorsomedial prefrontal cortex (dmPFC) plays a central role in processing first impressions; however, little is known about how dmPFC processes different valences of first impressions. Moreover, it is still unclear as to whether the dmPFC shows lateralization or only induces different levels of activation when processing positive and negative impressions. To address these questions in the present study, the brain activities for the impression judgments expressed by participants were measured with near-infrared spectroscopy. For each real facial picture, participants were asked to evaluate their first impressions on a scale from 'bad' to 'good' using a keyboard. The results showed that although the right dmPFC has a higher sensitivity in processing impressions, both the hemispheres of dmPFC showed a significant trend where the activation of positive impressions was higher than the negative ones. Accordingly, it is proposed that the dmPFC acts as a single mechanism responsible for delineating the processing of first impressions rather than two lateralized systems. Therefore, a 'positivity dominance hypothesis' is also proposed, which states that dmPFC in both hemispheres have a higher sensitivity and priority for positive impressions than negative ones. The present study provides valuable findings with respect to the role of the dmPFC in the processes of first impression formation.