The aim of our study was to assess the combined impact of UVR (280–400 nm) and temperature on the first larval stage (Zoea I) of three crab species from the Patagonian coast: Cyrtograpsus altimanus, C. angulatus,and Leucippa pentagona. We determined the survival response of newly hatched Zoea I after being exposed for 8–10 h under a solar simulator (Hönle SOL 1200) at 15 and 20 °C. There was no mortality due to Photosynthetic Active Radiation (PAR, 400–700 nm) or ultraviolet-A radiation (UV-A, 315–400 nm), and all the observed mortality was due to ultraviolet-B radiation (UV-B, 280–315 nm). The data of larval mortality relative to exposure time was best fit using a sigmoid curve. Based on this curve, a threshold (Th) and the lethal dose for 50% mortality (LD₅₀) were determined for each species. Based on the Th and LD₅₀, C. altimanus was found to be the most resistant species, while L. pentagona was found to be the most sensitive to UV-B. For both species of Cyrtograpsus, mortality was significantly lower at 20 °C than at 15 °C; however, no significant differences between the two temperature treatments were found in L. pentagona. Bioaccumulation of UV-absorbing compounds in the gonads and larvae of C. altimanus, and to a lesser extent in C. angulatus, might have contributed for counteracting the impact of UV-B. However, most of the resilience to UV-B observed with the increase in temperature might be due to an increase in metabolic activity caused by a repair mechanism mediated by enzymes. Full article

We provide a direct comparison of the distribution and abundance of mycosporine-like amino acids (MAAs) in a diverse range of microalgal cultures (33 species across 13 classes) grown without supplementary ultraviolet radiation (UV). We compare the MAAs in cultures with those present in characterised natural phytoplankton populations from the English Channel. We detected 25 UV absorbing compounds including at least two with multiple absorption maxima. We used LC-MS to provide chemical characterisation of the six most commonly occurring MAAs, namely, palythene, palythine, mycosporine-glycine, palythenic acid, porphyra-334 and shinorine. MAAs were abundant (up to 7 pg MAA cell⁻¹)in 10 species, with more minor and often unknown MAAs in a further 11 cultures. Shinorine was the most frequently occurring and abundant MAA (up to 6.5 pg cell⁻¹) and was present in all but two of the MAA-containing species. The study provides further insight into the diversity and abundance of MAAs important from an ecological perspective and as potential source of natural alternatives to synthetic sunscreens. Full article

Mycosporine-like amino acids (MAAs) and scytonemin are UV-screening compounds that have presumably appeared early in the history of life and are widespread in cyanobacteria. Natural colonies of the UV-insensitive Nostoc flagelliforme were found to be especially rich in MAAs (32.1 mg g DW^-1), concentrated in the glycan sheath together with scytonemin. MAAs are present in the form of oligosaccharide-linked molecules. Photosystem II activity, measured using PAM fluorescence and oxygen evolution, was used as a most sensitive physiological parameter to analyse the effectiveness of UV-protection. Laboratory experiments were performed under controlled conditions with a simulated solar radiation specifically deprived of UV-wavebands with cut-off filters (295, 305, 320, 345 and 395 nm). The UV-insensitivity of N. flagelliforme was found to cover the whole UV-A (315–400 nm) and UV-B (280–320 nm) range and is almost certainly due to the complementary UV-absorption of MAAs and scytonemin. The experimental approach used is proposed to be suitable for the comparison of the UV-protection ability in organisms that differ in their complement of UV-sunscreen compounds. Furthermore, this study performed with a genuinely terrestrial organism points to the relevance of marine photoprotective compounds for life on Earth, especially for the colonization of terrestrial environments. Full article

Taxonomically diverse marine, freshwater and terrestrial organisms have evolved the capacity to synthesize, accumulate and metabolize a variety of UV-absorbing substances called mycosporine-like amino acids (MAAs) as part of an overall strategy to diminish the direct and indirect damaging effects of environmental ultraviolet radiation (UVR). Whereas the enzymatic machinery to synthesize MAAs was probably inherited from cyanobacteria ancestors via the endosymbionts hypothesis, metazoans lack this biochemical pathway, but can acquire and metabolize these compounds by trophic transference, symbiotic or bacterial association. In this review we describe the structure and physicochemical properties of MAAs, including the recently discovered compounds and the modern methods used for their isolation and identification, updating previous reviews. On this basis, we review the metabolism and distribution of this unique class of metabolites among marine organism. Full article

Marine organisms form a prominent component of the oceanic population, which significantly contribute in the production of cosmeceutical and pharmaceutical molecules with biologically efficient moieties. In addition to the molecules of various biological activities like anti-bacterial, anti-cancerous, anti-inflammatory and anti-oxidative etc., these organisms also produce potential photoprotective or anti-photoaging agents, which are attracting present day researchers. Continuous exposure to UV irradiation (both UV-A and UV-B) leads to the skin cancer and other photoaging complications, which are typically mediated by the reactive oxygen species (ROS), generated in the oxidative pathways. Many of the anti-oxidative and anti-photoaging compounds have been identified previously, which work efficiently against photodamage of the skin. Recently, marine originated photoprotective or anti-photoaging behavior was observed in the methanol extracts of Corallina pilulifera (CPM). These extracts were found to exert potent antioxidant activity and protective effect on UV-A-induced oxidative stress in human dermal fibroblast (HDF) cells by protecting DNA and also by inhibiting matrix metalloproteinases (MMPs), a key component in photoaging of the skin due to exposure to UV-A. The present review depicts various other photoprotective compounds from algae and other marine sources for further elaborative research and their probable use in cosmeceutical and pharmaceutical industries. Full article