Differential Responses to UV-A Stress Recorded in Carotenogenic Microalgae Haematococcus rubicundus, Bracteacoccus aggregatus, and Deasonia sp.

Abstract

UV-A is the main ultraviolet component of natural (solar) radiation. Despite it, its effect on phototrophs is studied less than UV-B. Effects of UV-A on photosynthetic apparatus of three carotenoid-producing microalgae were elucidated. Photosynthetic activity was studied using chlorophyll fluorescence analysis. Cell extracts were evaluated by absorbance spectroscopy. On the one hand, there were some common features of three strains. In all cases the changes involved PSII primary photochemistry and antennae size. All strains accumulated UV-absorbing polar compounds. On the other hand, some responses were different. Upregulation of non-photochemical quenching was observed only in B. aggregatus BM5/15, whereas in other cases its level was low. H. rubicundus BM7/13 and Deasonia sp. NAMSU 934/2 accumulated secondary carotenoids, whereas B. aggregatus BM5/15 accumulated primary ones. Microscopic features of the cultures were also different. H. rubicundus BM7/13 and Deasonia sp. NAMSU 934/2 were represented mostly by solitaire cells or small cell clusters, lacking their green color; the cells of B. aggregatus BM5/15 formed aggregates from green cells. Cell aggregation could be considered as an additional UV-protecting mechanism. Finally, the strains differed by their viability. B. aggregatus BM5/15 was most resistant to UV-A, whereas massive cell death was observed in two other cultures.

Diversity and Distribution of Carotenogenic Algae in Europe: A Review

“…The fact of carotenoids accumulation has been noticed for Deasonia granata [ 194 ] and the strain Deasonia sp. NAMSU 934/2 [ 90 ] ( Figure 4 l). No data have been published on the carotenoid composition of these strains.…”

“…No data have been published on the carotenoid composition of these strains. Based on the absorbance spectra of pigment extracts [ 90 ], Deasonia sp. NAMSU 934/2 accumulates ketocarotenoids under stress conditions.…”

“…The strain Deasonia sp. CALU 934 was isolated from the soil samples on the shore of a lake in the Gvardeyskoye Settlement, Leningrad Oblast, European part of Russia [ 90 , 195 ]. The strain defined as Deasonia granata ACKU 566–06 (authentic strain of the genus) was isolated by Pringsheim from soil in the vicinity of the city of Praha (former Czechoslovakia) [ 116 , 117 ], the strain Deasiona garanata ACSSI 150 was isolated from the soil in Gomel (Belarus) [ 196 ] ( Table 2 ).…”

“… Representatives of carotenogenic algae inhabiting Europe. ( a ) Haematococcus lacustris , scale bar = 10 μm, adapted with permission from [ 69 ] © Springer Nature B.V., 2020; ( b ) Ettlia carotinosa , scale bar = 5 μm (unpublished); ( c ) Dunaliella salina , scale bar—not provided, adapted from [ 1 ] © Springer Nature B.V., 2005; ( d ) Chromochloris zofingiensis , scale bar = 5 μm, adapted from [ 83 ]; ( e ) Chloromonas krienitzii , scale bar = 10 μm, adapted from [ 84 ]; ( f ) Chlainomonas sp., scale bar = 10 μm, adapted from [ 85 ] © Taylor & Francis Online, 2018; ( g ) Sanguina nivaloides , scale bar = 5 μm, adapted from [ 86 ] © Oxford Academic, 2019; ( h ) Coelastrella rubescens , scale, bar = 10 μm, adapted from [ 70 ]; ( i ) Bracteacoccus aggregatus , scale bar = 10 μm, adapted with permission from [ 87 ] © Oxford Academic, 2020; ( j ) Halochlorella rubescens , scale bar = 5 μm, adapted with permission from [ 88 ] © Pleiades Publishing, Ltd., 2022; ( k ) Tetraëdron minimum , scale bar = 20 μm, adapted from [ 89 ] © Iheringia, Série Botânica, 2016; ( l ) Deasonia sp., scale bar = 5 μm, adapted with permission from [ 90 ]; ( m ) Chlorosarcinopsis bastropiensis , scale bar = 10 μm, adapted with permission from [ 91 ]; ( n ) Acetabularia acetabulum , scale bar—not provided, adapted from [ 92 ] © Inter-Research Science Publisher, 2012; ( o ) Pseudospongiococcum protococcoides , scale bar = 10 μm, adapted from [ 93 ] © Phytocenter, 2013; ( p ) Protosiphon botryoides , scale bar = 20 μm, adapted with permission from [ 94 ] © Taylor & Francis Online, 2019; ( q ) Botryococcus braunii , scale bar = 40 μm, adapted from [ 95 ]; ( r ) Golenkinia brevispicula , scale bar = 10 μm, adapted with permission from [ 96 ] © Elsevier, 2020; ( s ) Euglena sanguinea , scale bar = 20 μm, adapted with permission from [ 97 ] © Taylor & Francis Online, 2021; ( t ) Trachelomonas volvocina , scale bar 10 μm, adapted from [ 98 ] © TÜBİTAK libraries, 2013; ( u ) Tovellia sanguinea , scale bar = 10 μm, adapted with permission from [ 99 …”

Microalgae Photo-Protectants and Related Bio-Carriers Loaded with Bioactive Entities for Skin Applications—An Insight of Microalgae Biotechnology

“…This shows that more research must be completed to determine the resistance of more microalgae; however, this research has established the initial step for a new opportunity in the production of sunscreens based on these compounds that confer resistance to UV rays. Table 1 shows a summary of the findings on some of the most relevant UV-resistant microalgae along with their resistance factor and the experimental conditions to which they were exposed [ 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 ].…”