The effect of shock freezing on physiological properties and consequent growth of Antarctic filamentous (Stigeoclonium sp.) and coccal alga (Diplosphaera chodatii) on agar plates

We studied the changes in PSII photochemical processes in the cells of Antarctic algae Klebsormidium sp. and Stigeoclonium sp. exposed to salinity stress (0 – 3M NaCl) for 3 h. Salinity stress induced a decrease in the potential (FV/FM) and effective quantum yield of PSII electron transport (FPSII). Salinity stress induced a decrease in vitality index (Rfd, relative decrease of chlorophyll fluorescence). Analyses of the polyphasic fast chlorophyll fluorescence transients (OJIP) showed that with the increase in salt concentration, the chlorophyll fluorescence signals recorded at the phases J, I, and P declined, and the transient flattened with increaseing NaCl concentration reaching close to zero ChlF values at salt concentration of 3 M NaCl after 180 min. exposition. Klebsormidium sp. was found more salinity stress resistant than Stigeoclonium sp.

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“…For Stigeoclonium sp. from Antarctic habitats, resistence to sub-zero temperature has been studied (Orekhova et al 2019).…”

Section: Experimental Speciesmentioning

confidence: 99%

Species-specific responses of Antarctic terrestrial microalgae to salinity stress. Comparative study in Klebsormidium sp. and Stigeoclonium sp.

Canora¹,

Llorens²,

Sicilia³

2022

Czech Polar Rep.

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“…In this context, the cell cluster of Diplosphaera spp. may be surrounded by a gelatinous matrix ensuring a high desiccation tolerance (Orekhova et al 2019). Members of the genus Coccomyxa occur as soil algae or free-living in terrestrial green biofilms and associated with mosses (Darienko et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Enhancing carotenogenesis in terrestrial microalgae by UV-A light stress

et al. 2022

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Carotenoids are among the most widely distributed pigments in nature with broad application options in pharmacology, cosmetics and food industries. For commercial-scale production using microalgae, however, it is crucial to find the best performing strains regarding growth and yields of the products of interest. As terrestrial microalgae present the ability to quickly adapt to changing or unfavorable environmental conditions through cell-specific defense mechanisms, they constitute highly promising candidates. The present study thus aimed to investigate the potential of five terrestrial microalgal strains to increasingly produce the carotenoids β-carotene, canthaxanthin and astaxanthin when being exposed to UV-A stress. Light stress experiments were performed using a novel irradiation system based on UV-LED technology. Microalgal cultures were treated with UV-A radiation to stimulate carotenogenesis and the time-dependent effects were investigated by high-performance liquid chromatography analysis. The potential of the microalgae to enhance de novo biosynthesis of the targeted metabolites under the influence of UV-A light could be confirmed by significantly increased yields of canthaxanthin in four out of five strains and by a significantly enhanced β-carotene concentration in at least one strain during 72 h of investigation. Overall, the results provided evidence that UV-A light stress can be effective in rapidly inducing carotenogenesis in terrestrial microalgae and thus harbors vast potential for further exploitation regarding large-scale carotenoid production.

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Diplosphaera elongata sp. nova: Morphology and Phenotypic Plasticity of This New Microalga Isolated from Lichen Thalli

et al. 2023

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Lichen phycobiomes have recently emerged as a source of biodiversity and new species of microalgae. Although in the genus Diplosphaera free-living microalgae are common, numerous strains belonging to this genus have frequently been recognized or isolated from lichen thalli. In this study, a comprehensive analysis of the strain Diplosphaera sp. ASUV135, isolated from a lichen thallus, has been carried out using an integrative taxonomic approach. The SSU and nuclear-encoding ITS rDNA, as well as the chloroplast rbcL gene, were sequenced and analyzed to ascertain its taxonomic position and phylogenetic relationships within the genus Diplosphaera. This strain was also analyzed by light, confocal and transmission microscopy for morphological and ultrastructural characterization. The phenotypic plasticity in this strain was also confirmed by changes in its morphology under different growth conditions, as well as those of modulated Chlorophyll a fluorescence emissions, to understand its photosynthetic functioning. Our results pointed out that this strain represents a new taxon within the genus Diplosphaera (Prasiola group), described here as Diplosphaera longate sp. nova. This study also provides tools for future research on organisms with high phenotypic plasticity by using molecular, morphological, ultrastructural and physiological approaches

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The effect of shock freezing on physiological properties and consequent growth of Antarctic filamentous (Stigeoclonium sp.) and coccal alga (Diplosphaera chodatii) on agar plates

Cited by 4 publications

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Species-specific responses of Antarctic terrestrial microalgae to salinity stress. Comparative study in Klebsormidium sp. and Stigeoclonium sp.

Species-specific responses of Antarctic terrestrial microalgae to salinity stress. Comparative study in Klebsormidium sp. and Stigeoclonium sp.

Enhancing carotenogenesis in terrestrial microalgae by UV-A light stress

Diplosphaera elongata sp. nova: Morphology and Phenotypic Plasticity of This New Microalga Isolated from Lichen Thalli

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