Human skin is constantly exposed to damaging ultraviolet radiation (UVR), which induces a number of acute and chronic disorders. To reduce the risk of UV-induced skin injury, people apply an additional external protection in the form of cosmetic products containing sunscreens. Nowadays, because of the use of some chemical filters raises a lot of controversies, research focuses on exploring novel, fully safe and highly efficient natural UV-absorbing compounds that could be used as active ingredients in sun care products. A promising alternative is the application of multifunctional mycosporine-like amino acids (MAAs), which can effectively compete with commercially available filters. Here, we outline a complete characterization of these compounds and discuss their enormous biotechnological potential with special emphasis on their use as sunscreens, activators of cells proliferation, anti-cancer agents, anti-photoaging molecules, stimulators of skin renewal, and functional ingredients of UV-protective biomaterials.

dCyanobacteria produce numerous volatile organic compounds (VOCs), such as ␤-cyclocitral, geosmin, and 2-methylisoborneol, which show lytic activity against cyanobacteria. Among these compounds, only ␤-cyclocitral causes a characteristic color change from green to blue (blue color formation) in the culture broth during the lysis process. In August 2008 and September 2010, the lysis of cyanobacteria involving blue color formation was observed at Lake Tsukui in northern Kanagawa Prefecture, Japan. We collected lake water containing the cyanobacteria and investigated the VOCs, such as ␤-cyclocitral, ␤-ionone, 1-propanol, 3-methyl-1-butanol, and 2-phenylethanol, as well as the number of cyanobacterial cells and their damage and pH changes. As a result, the following results were confirmed: the detection of several VOCs, including ␤-cyclocitral and its oxidation product, 2,2,6-trimethylcyclohexene-1-carboxylic acid; the identification of phycocyanin based on its visible spectrum; the lower pH (6.7 and 5.4) of the lysed samples; and characteristic morphological change in the damaged cyanobacterial cells. We also encountered the same phenomenon on 6 September 2013 in Lake Sagami in northern Kanagawa Prefecture and obtained almost the same results, such as blue color formation, decreasing pH, damaged cells, and detection of VOCs, including the oxidation products of ␤-cyclocitral. ␤-Cyclocitral derived from Microcystis has lytic activity against Microcystis itself but has stronger inhibitory activity against other cyanobacteria and algae, suggesting that the VOCs play an important role in the ecology of aquatic environments.

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Macroporous polyacrylamide gels (MPAAG) with iminodiacetic acid (IDA) functionality were prepared by (i) chemical modification of polyacrylamide gel, (ii) co-polymerization of acrylamide with allyl glycidyl ether (AGE) and N,N'metylene-bis(acrylamide) (MBAAm) followed by coupling IDA ligand or (iii) by copolymerization of acrylamide and MBAAm with functional monomer carrying IDA-functionality (1-(N,N-bis(carboxymethyl)amino-3-allylglycerol). Screening for optimized conditions for the production of the MPAAG with required porous properties was performed in a 96-well chromatographic format that allowed parallel production and analysis of the MPAAG prepared from reaction mixtures with different compositions. Scanning electron microscopy of the fabricated MPAAG revealed two different types of the porous structures: monomodal macroporous structure with large interconnected pores separated by dense non-porous pore walls in case of plain gels or gels produced via copolymerization with AGE. The other type of the MPAAG (gel produced via co-polymerization with functional monomer carrying IDA-functionality) had bimodal pore structure with large interconnected pores separated by the pore walls pierced through with micropores. The effect of different modifications of MPAAG monoliths and of porous structure of the MPAAG (monomodal and bimodal porous structure) on protein binding has been evaluated.

Nineteen compounds isolated from field samples of cyanobacteria Woronichinia naegeliana (Unger) Elenkin were identified. They fell into four classes of peptides: cyanopeptolins (cyanopeptolin B, cyanopeptolin C, cyanopeptolin D, cyanopeptolin 880, micropeptin 88D, micropeptin 478-B, micropeptin SD999, micropeptin T2, planktopeptin BL1061), microginins (microginin 478, microginin 757, microginin 51A, microginin 91E, microginin FR3, microginin FR4), anabaenopeptins (oscillamide B) and possibly microcystins (trace amounts of microcystin-LR) showing respectively fragment patterns in their electrospray ion source-MS spectra. The molecular masses of the determined peptides range from 700 to 1100 Da. These results confirm the remarkable ability of cyanobacteria to synthesize a wide array of peptides.

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The cyanobacterium Microcystis produces volatile organic compounds such as β-cyclocitral and 3-methyl-1-butanol. The lysis of cyanobacteria involving the blue color formation has been occasionally observed in a natural environment. In this study, we focused on the oxidation behavior of β-cyclocitral that contributed to the blue color formation in a natural environment and compared β-cyclocitral with a structurally related compound concerning its oxidation, acidification, and lytic behavior. The oxidation products of β-cyclocitral were identified by the addition of β-cyclocitral in water, in which 2,2,6-trimethylcyclohex-1-ene-1-yl formate and 2,2,6-trimethylcyclohexanone were structurally characterized. That is, β-cyclocitral was easily oxidized to produce the corresponding carboxylic acid and the enol ester in water without an oxidizing reagent, suggesting that this oxidation proceeded according to the Baeyer-Villiger oxidation. The oxidation behavior of β-cyclocitral in a laboratory was different from that in the natural environment, in which 2,2,6- trimethylcyclohexanone was detected at the highest amount in the natural environment, whereas the highest amount in the laboratory was β-cyclocitric acid. A comparison of β-cyclocitral with structurally similar aldehydes concerning the lytic behavior of a Microcystis strain and the acidification process indicated that only β-cyclocitral was easily oxidized. Furthermore, it was found that a blue color formation occurred between pH 5.5 and 6.5, suggesting that chlorophyll a and β-carotene are unstable and decomposed, whereas phycocyanin was stable to some extent in this range. The obtained results of the characteristic oxidation behavior of β-cyclocitral would contribute to a better understanding of the cyanobacterial life cycle.