The comet assay as a method for assessing dna damage in cryopreserved samples.

The preservation of the nuclear genome's integrity is paramount for the viability and overall health of cells, tissues, and organisms. DNA, being susceptible to damage under physiological conditions and vulnerable to both endogenous and environmental factors, faces constant threats. To assess DNA damage and repair within individual eukaryotic cells, the comet assay presents itself as a versatile, gel electrophoresis-based, relatively simple, and highly sensitive method. Originally designed to monitor DNA damage and repair within populations of mammalian cells, the comet assay has now found applications across diverse domains, including yeast, protozoa, plants, and invertebrates. This technique has proven invaluable in cryopreservation studies, serving as a valuable adjunct for determining suitable cryopreservation protocols. These protocols encompass choices related to cryoprotectants, sample preparation, as well as storage conditions in terms of time and temperature. In the realm of animal cryopreservation research, the comet assay stands as a gold-standard method for assessing DNA integrity. Nevertheless, when applied in plant-oriented investigations, additional efforts are essential due to the distinct nature of plant cells and associated technical challenges. This review elucidates the fundamental principles underlying the comet assay, discusses its current iterations, and delineates its applications in the cryopreservation of both animal and plant specimens. Moreover, we delve into the primary challenges confronting the comet assay's utility as a monitoring tool in the context of plant sample cryopreservation. https://doi.org/10.54680/fr24110110112.

Development and characterisation of an irradiation device for biomedical studies covering the solar spectrum with individual regulated spectral bands.

To understand the importance of terrestrial solar exposure on human skin, not only individual spectral components need to be considered in biomedical studies, but also the relevance of the combined action profile of the complete solar spectrum (cSS) must be established. We therefore developed a novel irradiation device that combines the emission of four individual lamps (UVB, UVA, VIS and nIR) to achieve exposure from 280 to 1400 nm with individual controllable lamps. The integrated irradiance of each spectral band is similar to the solar spectrum. The lamps can be utilised individually or in any desired combination. Here we present the design, realisation, and validation of this irradiation device as well as biological results on cellular metabolism (MTT assay), cell cycle alterations, and clonogenic growth in HaCaT cells after exposures to the individual spectral bands as well as their simultaneous combinations. Thereby, we demonstrate that UVB combined with UVA is the main determinant for the metabolic activity within cSS. Also, UVB-dependent effects dominate cell cycle regulation in cSS, whilst UVA and nIR have little influence. Lastly, also clonogenic growth is dominated by the UVB action profile in cSS, despite nIR showing modulatory activity when applied in combination with UVB. Together, this highlights the regulatory influence of the different spectral bands on the three biological endpoints and demonstrates their modulation when being part of the complete solar spectrum.