Abstract
Accumulation of mycosporine-like amino acids (MAAs) has been reported
in a wide range of species in nature, including microalgae, macroalgae, cyanobacteria,
phytoplankton, fungi, and some animals. This chapter describes the distribution of
MAAs with a focus on macroalgae and cyanobacteria. MAAs biosynthesized by
macroalgae have already been applied in cosmetic products, such as Helioguard 365
and Helinori. Macroalgae tend to accumulate multiple types of MAAs, and the types
and accumulation levels are affected by changes in environmental factors. Regarding
cyanobacteria, we focus on UV, salt, and osmotic stresses, temperature changes, and
drought stress as environmental factors, and describe the species in which the
accumulations of MAAs are induced by these stresses. UV-B irradiation is a common
environmental factor that can induce the accumulation of MAAs in cyanobacteria, but
induction by other abiotic stresses has been reported. These findings suggest that
MAAs act as a multifunctional molecule that responds to a variety of environmental
factors, not just as a UV absorber.