Effect of Technically Relevant X-Ray Doses on the Structure and Function of Alcohol Dehydrogenase and Hen Egg-White Lysozyme.

PURPOSE: The effect of different irradiation doses on the structure and activity of lyophilized powders of Hen Egg-White Lysozyme (HEWL) and alcohol dehydrogenase (ADH) was investigated using these substances as models for robust and sensitive proteins, respectively. Three doses were selected to cover the ranges of radio-sterilization (25kGy), treatment of blood products (25Gy) and annual background radiation dose (approximately 2mGy). The results offer an initial screening of different irradiation doses and support the development of X-ray imaging methods as non-destructive process analytical technology (PAT) tools for detecting the visible particulate matters in such products. METHODS: HEWL and ADH were exposed to X-rays in the solid state. The effect of irradiation was determined directly after irradiation and after storage. Structural changes and degradation were investigated using SAXS, SDS-PAGE and HPLC-MS. Protein functionality was assessed via activity assays. RESULTS: Lower irradiation doses of 25Gy and 2mGy had no significant impact on the structure and enzyme activity. The dose of 25kGy caused a significant decrease in the enzyme activity and structural changes immediately after irradiation of ADH and after storage of irradiated HEWL at -20°C. CONCLUSION: The results emphasize the importance of careful selection of radiation doses for development of X-ray imaging methods as PAT tools inspection of solid biopharmaceutical products.

Effect of Temperature and Photoperiod on Development, Survival, and Growth Rate of Mealworms, Tenebrio molitor.

Insects are a potential substitute for conventional meat and can be part of a sustainable human diet due to their valuable nutrients and relatively low environmental production impact. One species that is already produced for human consumption and livestock feed is the mealworm, i.e., larvae of Tenebrio molitor. Knowledge of the effects of temperature, and particularly photoperiod, on mealworm development is scarce, but crucial for the improvement of rearing. Therefore, the effects of three temperatures (20 °C, 25 °C, and 30 °C), in combination with three photoperiods (long-day-16 h:8 h light:dark; short-day-8 h:16 h light:dark, and constant darkness) on mealworm survival, developmental time, and growth rate were tested. We describe a significant effect of temperature on survival rate, developmental time, and growth rate. Furthermore, significant effects of photoperiod on developmental time and growth rate were found. At 25 and 30 °C and constant darkness, the highest survival and growth rate, along with the shortest developmental time, were observed. Our data can be used to improve the mass rearing of mealworms for an efficient production of food and feed.