The evolution of glutathione metabolism in phototrophic microorganisms

Fahey, Robert C.; Buschbacher, Ralph M.; Newton, Gerald L.

doi:10.1007/bf02100044

Cited by 62 publications

(31 citation statements)

References 41 publications

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“…The first in this group, Chlorella sorokiniana UTEX 1230, has been studied extensively for its carbohydrate, lipid, protein, and biopolymer content [48]–[50] as well as hydrogen photoproduction [51], glucose transport [52], production of biomolecules by fermentation [53], [54], and bioremediation capabilities [55]–[58]. This organism was isolated by Sorokin and Meyers in the early 1950s [59] and maintained in many culture collections under different strain numbers (originally classified as C. pyrenoidosa ) [60]–[64].…”

Section: Resultsmentioning

confidence: 99%

Comparative Analyses of Three Chlorella Species in Response to Light and Sugar Reveal Distinctive Lipid Accumulation Patterns in the Microalga C. sorokiniana

et al. 2014

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While photosynthetic microalgae, such as Chlorella, serve as feedstocks for nutritional oils and biofuels, heterotrophic cultivation can augment growth rates, support high cell densities, and increase triacylglycerol (TAG) lipid content. However, these species differ significantly in their photoautotrophic and heterotrophic characteristics. In this study, the phylogeny of thirty Chlorella strains was determined in order to inform bioprospecting efforts and detailed physiological assessment of three species. The growth kinetics and lipid biochemistry of C. protothecoides UTEX 411, C. vulgaris UTEX 265, and C. sorokiniana UTEX 1230 were quantified during photoautotrophy in Bold's basal medium (BBM) and heterotrophy in BBM supplemented with glucose (10 g L−1). Heterotrophic growth rates of UTEX 411, 265, and 1230 were found to be 1.5-, 3.7-, and 5-fold higher than their respective autotrophic rates. With a rapid nine-hour heterotrophic doubling time, Chlorella sorokiniana UTEX 1230 maximally accumulated 39% total lipids by dry weight during heterotrophy compared to 18% autotrophically. Furthermore, the discrete fatty acid composition of each strain was examined in order to elucidate lipid accumulation patterns under the two trophic conditions. In both modes of growth, UTEX 411 and 265 produced 18∶1 as the principal fatty acid while UTEX 1230 exhibited a 2.5-fold enrichment in 18∶2 relative to 18∶1. Although the total lipid content was highest in UTEX 411 during heterotrophy, UTEX 1230 demonstrated a two-fold increase in its heterotrophic TAG fraction at a rate of 28.9 mg L−1 d−1 to reach 22% of the biomass, corresponding to as much as 90% of its total lipids. Interestingly, UTEX 1230 growth was restricted during mixotrophy and its TAG production rate was suppressed to 18.2 mg L−1 d−1. This constraint on carbon flow raises intriguing questions about the impact of sugar and light on the metabolic regulation of microalgal lipid biosynthesis.

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Section: Resultsmentioning

confidence: 99%

Comparative Analyses of Three Chlorella Species in Response to Light and Sugar Reveal Distinctive Lipid Accumulation Patterns in the Microalga C. sorokiniana

et al. 2014

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“…Only if a species is adapted to the environment, will it survive. The fact that only phototrophic eubacteria contain GSH indicates that GSH evolved in parallel to oxygenic photosynthesis [36]. Furthermore, GSTs are evolutionarily-conserved, and homologous domains can be found back to early prokaryotes.…”

Section: Long Term Adaptation—transcriptional Epigenetic and Genmentioning

confidence: 99%

“…In the end this will result in an up-regulation of γGCS. Additionally, acrolein is thought to activate p38MAPK that have been shown to have an effect on the activity and expression of certain lysine acetyl-transferases (e.g., KAT3A/KAT3B (CBP/p300)) [36,46]. Furthermore, via this mechanism, the expression of GSH system-related genes could be modified.…”

Section: Adaptation Induced By Acroleinmentioning

confidence: 99%

Time in Redox Adaptation Processes: From Evolution to Hormesis

Sthijns

Weseler

Bast

et al. 2016

IJMS

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Life on Earth has to adapt to the ever changing environment. For example, due to introduction of oxygen in the atmosphere, an antioxidant network evolved to cope with the exposure to oxygen. The adaptive mechanisms of the antioxidant network, specifically the glutathione (GSH) system, are reviewed with a special focus on the time. The quickest adaptive response to oxidative stress is direct enzyme modification, increasing the GSH levels or activating the GSH-dependent protective enzymes. After several hours, a hormetic response is seen at the transcriptional level by up-regulating Nrf2-mediated expression of enzymes involved in GSH synthesis. In the long run, adaptations occur at the epigenetic and genomic level; for example, the ability to synthesize GSH by phototrophic bacteria. Apparently, in an adaptive hormetic response not only the dose or the compound, but also time, should be considered. This is essential for targeted interventions aimed to prevent diseases by successfully coping with changes in the environment e.g., oxidative stress.

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“…Subsequently bacterial GSTs associated with the beta, chi, theta and zeta classes have been identified and GSTs of the MAPEG (membrane-associated proteins involved in ecosanoid and glutathione metabolism) class have also been determined (13). Most of these GSTs are found in proteobacteria and cyanobacteria, phyla generally found to produce GSH (16-18). The rates for bacterial GSTs are substantially lower (5-200-fold) than those of mammalian liver GSTs (19).…”

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confidence: 99%

The DinB Superfamily Includes Novel Mycothiol, Bacillithiol, and Glutathione S-Transferases

et al. 2011

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The superfamily of glutathione S-transferases has been the subject of extensive study but Actinobacteria produce mycothiol (MSH) in place of glutathione and no mycothiol S-transferase (MST) has been identified. Using mycothiol and monochlorobimane as substrates a MST activity was detected in extracts of Mycobacterium smegmatis and purified sufficiently to allow identification of MSMEG_0887, a member the DUF664 family of the DinB superfamily, as the MST. The identity of the M. smegmatis and homologous Mycobacterium tuberculosis (Rv0443) enzymes was confirmed by cloning and the expressed proteins were found to be active with MSH but not bacillithiol (BSH) or glutathione (GSH). Bacillus subtilis YfiT is another member of the DinB superfamily but this bacterium produces BSH. The YfiT protein was shown to have S-transferase activity with monochlorobimane when assayed with BSH but not with MSH or GSH. Enterococcus faecalis EF_3021 shares some homology with MSMEG_0887 but this organism produces GSH but not MSH or BSH. Cloned and expressed EF_0321 was active with monochlorobimane and GSH but not with MSH or BSH. MDMPI_2 is another member of the DinB superfamily and has been previously shown to have mycothiol-dependent maleylpyruvate isomerase activity. Three of the eight families of the DinB superfamily include proteins shown to catalyze thiol-dependent metabolic or detoxification activities. Since more than two-thirds of the sequences assigned to the DinB superfamily are members of these families it seems likely that such activity is dominant in the DinB superfamily.

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The evolution of glutathione metabolism in phototrophic microorganisms

Cited by 62 publications

References 41 publications

Comparative Analyses of Three Chlorella Species in Response to Light and Sugar Reveal Distinctive Lipid Accumulation Patterns in the Microalga C. sorokiniana

Comparative Analyses of Three Chlorella Species in Response to Light and Sugar Reveal Distinctive Lipid Accumulation Patterns in the Microalga C. sorokiniana

Time in Redox Adaptation Processes: From Evolution to Hormesis

The DinB Superfamily Includes Novel Mycothiol, Bacillithiol, and Glutathione S-Transferases

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