Changes in ATPase activity, antioxidant enzymes and proline biosynthesis in yeast Candida guilliermondii NP-4 under X-irradiation.

This study investigates the effects of X-radiation on ATPase activity and antioxidant enzyme activity, particularly enzymes involved in proline biosynthesis, in yeast C. guilliermondii NP-4. Moreover, the study examined the post-irradiation repair processes in these cells. Results showed that X-irradiation at a dose of 300 Gy led to an increase in catalase (CAT) and superoxide dismutase (SOD) activity, as well as, an increase in the CAT/SOD ratio in C. guilliermondii NP-4. The repair of radiation-induced damage requires a substantial amount of energy, resulting in an increased demand for ATP in the irradiated and repaired yeasts. Consequently, the total and FoF1-ATPase activity in yeast homogenates and mitochondria increased after X-irradiation and post-irradiation repair. It was showed an increase in the activity of proline biosynthesis enzymes (ornithine transaminase and proline-5-carboxylate reductase) in X-irradiated C. guilliermondii NP-4, which remained elevated even after post-irradiation repair. As a result, the proline levels in X-irradiated and repaired yeasts were higher than those in non-irradiated cells. These findings suggest that proline may have a radioprotective effect on X-irradiated C. guilliermondii NP-4 yeasts. Taken together this study provides insights into the effects of X-radiation on ATPase activity, antioxidant enzyme activity, and proline biosynthesis in C. guilliermondii NP-4 yeast cells, highlighting the potential radioprotective properties of proline in X-irradiated yeasts.

Changes in growth kinetic parameters, morphology and mitotic activity of yeasts Candida guilliermondii exposed to the low-intensity waves of 51.8-GHz frequency.

Under the influence of electromagnetic waves of millimeter range with the frequency of 51.8 GHz, changes in the morphology, growth parameters and mitotic activity of yeasts C. guilliermondii NP-4 are revealed. Filamentous and giant cells appeared in a population of exposed yeasts. The sigmoid shape of the growth curve remained but the lag phase duration was increased by 2 h in comparison with non-exposed yeasts; accordingly, the log and stationary phases followed 2 h later. The specific growth rate in the log growth phase and colony-forming ability of exposed yeasts was decreased. It is suggested that yeasts have some response mechanisms to 51.8-GHz frequency electromagnetic waves. The results can be used to understand the response mechanisms of microorganisms to non-ionizing radiation, as well as to develop approaches to protect living organisms from it. The effect of electromagnetic waves of 51.8-GHz frequency to suppress yeasts can be applied in biotechnology and medicine.