Antioxidant Production in Dunaliella

Roy, Uttam K.; Nielsen, Birthe V.; Milledge, John J.

doi:10.3390/app11093959

Cited by 26 publications

(4 citation statements)

References 158 publications

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“…Plants may also enhance antioxidant capacity through enhancing the AsA-GSH cycle and the regeneration rates of AsA and GSH. Low levels of UV-B radiation increased the accumulation of GSH and GSSG, revealing a positive response of non-enzymatic antioxidants to UV-B exposure similar to that observed in other species of marine algae (Wang et al, 2007;Roy et al, 2021). Furthermore, the activities of GR, DHAR, and GPx involved in GSH regeneration also increased under low UV-B radiation.…”

Section: Regulation Of the Antioxidant System By Ros Under Uv-b Condi...supporting

confidence: 74%

Ultraviolet-B radiation stress triggers reactive oxygen species and regulates the antioxidant defense and photosynthesis systems of intertidal red algae Neoporphyra haitanensis

et al. 2022

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The enhancement of harmful ultraviolet-B (UV-B, 280–320 nm wavelength) radiation is a serious problem generally faced by photosynthetic organisms. Previous studies have reported that the currently increasing level of UV-B radiation received on earth can promote the formation of reactive oxygen species (ROS) by altering the antioxidant defense system or by hampering of photosynthesis system of plants. However, the relationship between the UV-B-induced ROS production, antioxidant capacity, and photosynthetic performance in macroalgae remains unclear. In this study, the regulation of the antioxidant system and photosynthetic activity by ROS triggered by UV-B radiation were investigated in an intertidal seaweed, Neoporphyra haitanensis. The contents of hydrogen peroxide and malondialdehyde increased with enhanced UV-B radiation, indicating N. haitanensis experienced oxidative stress. Increased activities of antioxidant enzymes showed a positive response of enzymatic antioxidants to maintain the balance of ROS under low UV-B conditions. Likewise, an accumulation of non-enzymatic antioxidants occurred and glutathione redox status was maintained at a high level, suggesting that the ascorbate–glutathione cycle played an indispensable role in detoxifying ROS. Nevertheless, high UV-B radiation markedly inhibited the efficiency of the enzymatic and non-enzymatic antioxidants, causing oxidative damage and a depression of photosynthesis. The addition of ROS scavengers alleviated the increased oxidation level caused by UV-B radiation, implying that oxidative damage under UV-B condition was ascribed to accumulated ROS. The activation of the antioxidant defense system was also modulated by ROS. Additionally, the decreased photosynthetic activities induced by enhanced UV-B radiation were reversed by ROS scavengers, indicating that ROS-mediated oxidative damage caused by UV-B radiation is one of the important causes of photo-inhibitory damage in N. haitanensis. Overall, these results shed some light on the close relationship between UV-B-induced ROS production, the antioxidant defense system, and photosynthetic performance in macroalgae, which helps to reveal their survival strategies for adapting to highly variable marine intertidal environments.

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Section: Regulation Of the Antioxidant System By Ros Under Uv-b Condi...supporting

confidence: 74%

Ultraviolet-B radiation stress triggers reactive oxygen species and regulates the antioxidant defense and photosynthesis systems of intertidal red algae Neoporphyra haitanensis

et al. 2022

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“…Enzymatic antioxidants prevent or delay the oxidation of other molecules by neutralizing reactive oxygen species (ROS) (Hasanuzzaman et al, 2020). These enzymes eliminate ROS by reducing the energy of free radicals or donating electrons to free radicals, constituting the first level of defense in the cell's antioxidant network (Roy et al, 2021). This study observed CAT, APX and GPOD activities of C. vulgaris in different growth phases.…”

Section: Enzymatic Antioxidants In C Vulgarismentioning

confidence: 84%

Antioxidative Responses of Chlorella vulgaris Under Different Growth Phases

Yusuf

Athirah²,

Suhaila³

2022

Squalen Bull. Marine Fisheries Postharvest Biotech.

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Chlorella vulqaris is a unicellular microorganism that offers health benefits due to its concentrated antioxidant production. This microalga has received huge attention due to its natural antioxidative property as an alternative antioxidant source because of its rapid growth, easy and flexible culture. Research to date only focuses on the growth and antioxidant production in a selected growth phase, especially exponential and stationary phases; however, so far, limited reports on the production of antioxidants in all growth phases of C. vulgaris. Thus, this study determines the growth, the enzymatic (Catalase, CAT; Ascorbate Peroxidase, APX; and guaiacol peroxidase, gPOD) specific activities and the amount of the non-enzymatic antioxidants (a-tocopherol, ascorbic acid and carotenoids) of C. vulgaris in five growth phases. Chlorella vulgaris was cultured in F/2 medium at 25±2 °C under laboratory conditions. CAT specific activities were the highest at the exponential phase (1.50±0.08 units/mg protein), whereas APX and gPOD were induced at the lag phases of 37.13±4.93 units/mg protein and 1.31±0.03 units/mg protein, respectively. The amount of a-tocopherol was accumulated at the stationary phase (97.3±4.18 µg/g.fwt), whereas the highest amount of ascorbic acid (266.67±22.22 µg/g.fwt) and carotenoids (8.16±2.52 µg/g.fwt) were at the decline phase. Production of enzymatic and non-enzymatic antioxidants in the microalgae cells indicated that they efficiently scavenged reactive oxygen species (ROS) and converted them into less harmful substances. In addition, the production of these antioxidants in different growth phases can be used as a guideline to produce massive antioxidants, which can be commercialized in the food and pharmaceutical industries.

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“…Reactive oxygen species (ROS) are important in cellular signaling, but stress conditions may cause increased ROS production and result in oxidative damage ( Rezayian et al, 2019 ). Various antioxidant defense systems to neutralize ROS exist in different cellular compartments, especially in organelles that are major sources of ROS such as H 2 O 2 ( Roy et al, 2021 ). The butyrate metabolic responses include a total of 10 proteins that are associated to antioxidant defense.…”

Section: Resultsmentioning

confidence: 99%

Proteomics unveil a central role for peroxisomes in butyrate assimilation of the heterotrophic Chlorophyte alga Polytomella sp.

Lacroux

Atteia²,

Brugière³

et al. 2022

Front. Microbiol.

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Volatile fatty acids found in effluents of the dark fermentation of biowastes can be used for mixotrophic growth of microalgae, improving productivity and reducing the cost of the feedstock. Microalgae can use the acetate in the effluents very well, but butyrate is poorly assimilated and can inhibit growth above 1 gC.L−1. The non-photosynthetic chlorophyte alga Polytomella sp. SAG 198.80 was found to be able to assimilate butyrate fast. To decipher the metabolic pathways implicated in butyrate assimilation, quantitative proteomics study was developed comparing Polytomella sp. cells grown on acetate and butyrate at 1 gC.L−1. After statistical analysis, a total of 1772 proteins were retained, of which 119 proteins were found to be overaccumulated on butyrate vs. only 46 on acetate, indicating that butyrate assimilation necessitates additional metabolic steps. The data show that butyrate assimilation occurs in the peroxisome via the β-oxidation pathway to produce acetyl-CoA and further tri/dicarboxylic acids in the glyoxylate cycle. Concomitantly, reactive oxygen species defense enzymes as well as the branched amino acid degradation pathway were strongly induced. Although no clear dedicated butyrate transport mechanism could be inferred, several membrane transporters induced on butyrate are identified as potential condidates. Metabolic responses correspond globally to the increased needs for central cofactors NAD, ATP and CoA, especially in the peroxisome and the cytosol.

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Antioxidant Production in Dunaliella

Cited by 26 publications

References 158 publications

Ultraviolet-B radiation stress triggers reactive oxygen species and regulates the antioxidant defense and photosynthesis systems of intertidal red algae Neoporphyra haitanensis

Ultraviolet-B radiation stress triggers reactive oxygen species and regulates the antioxidant defense and photosynthesis systems of intertidal red algae Neoporphyra haitanensis

Antioxidative Responses of Chlorella vulgaris Under Different Growth Phases

Proteomics unveil a central role for peroxisomes in butyrate assimilation of the heterotrophic Chlorophyte alga Polytomella sp.

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