Imaging the accumulated intracellular microalgal lipids as a response to temperature stress

Elsayed, Khaled N. M.; Колесникова, Т. А.; Noke, Anja; Klöck, Gerd

doi:10.1007/s13205-017-0677-x

Cited by 18 publications

(12 citation statements)

References 53 publications

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“…Initially, the optimal wavelength for excitation and emission was determined and it was noted that irrespective of DMSO and acetone concentrations, an excitation emission wavelength of 530/580 nm was found to be optimum for neutral lipid detection in Chlorella emersonii and Pseudokirchneriella subcapitata. This mirrors previous literature with similar microalgae strains (7,12,13,14). Subsequently, the optimum solvent to obtain maximum fluorescence intensity, for both Chlorella emersonii and Pseudokirchneriella subcapitata, was determined to be 20% (v/v) DMSO (see Figures 1, 3).…”

Section: Cell Concentrationsupporting

confidence: 85%

Nile Red assay development for the estimation of neutral lipids in Chlorella emersonii and Pseudokirchneriella subcapitata

Priyanka

Kinsella

Henehan

et al. 2020

The EuroBiotech Journal

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Fluorescent dyes offer a useful method for the measurement of intracellular lipids. They are inexpensive and require simple optical measurement instrumentation, whilst simultaneously providing high throughput application. Nile Red is a hydrophobic, metachromatic dye which has been widely used for detection of intracellular lipids. However, Nile Red fluorescence depends on its concentration, microenvironment polarity, incubation time and, therefore, requires strain specific optimization. Hence, neutral lipids in Chlorella emersonii and Pseudokirchneriella subcapitata cannot be quantified using existing Nile Red methods developed for other microalgae strains and, therefore an optimised procedure for these strains is required. In this method development, the optimal excitation and emission wavelengths were selected based on the solvent used for Nile Red dissolution. The effect of Nile Red concentration, microalgae cell concentration, incubation time on fluorescence intensity was explored and optimised. Quintuplet assay repeats were executed for increased assay robustness for two microalgae strains, Chlorella emersonii and Pseudokirchneriella subcapitata, with protocol reliability confirmed by fluorescence microscopy. In brief, 20% (v/v) DMSO containing 10μg/ml and 5μg/ml Nile red was found to be ideal concentration for neutral lipid estimation in Chlorella emersonii and Pseudokirchneriella subcapitata respectively when an incubation time of 60mins and 40mins at 40°C was used. This optimised Nile Red protocol is a robust, simple and cost-effective method for neutral lipid quantification in Chlorella emersonii and Pseudokirchneriella subcapitata.

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Section: Cell Concentrationsupporting

confidence: 85%

Nile Red assay development for the estimation of neutral lipids in Chlorella emersonii and Pseudokirchneriella subcapitata

Priyanka

Kinsella

Henehan

et al. 2020

The EuroBiotech Journal

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“…In eukaryotes, energy can be stored as triacylglycerol (TAG), which is an essential carbon source and an important component that contributes to survival under harsh environmental conditions [25]. Most microalgae accumulate triacylglycerols under conditions of nitrogen or phosphorus limitation, high salinity, and temperature stress [34][35][36]. Comparison of current study with previous reports of microalgae under low temperature, the highest biomass, lipid and fatty acids content of X. hormidioides was higher than other microalgae (Table 2).…”

Section: Discussionsupporting

confidence: 62%

The growth, lipid accumulation and adaptation mechanism in response to variation of temperature and nitrogen supply in psychrotrophic filamentous microalga Xanthonema hormidioides (Xanthophyceae)

Gao

Hong

Chen

et al. 2023

Biotechnol Biofuels

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Background Microalgae are promising feedstocks for production of renewable biofuels and value-added bioproducts. Temperature and nitrogen supply are important environmental and nutritional factors affecting the growth and metabolism of microalgae, respectively. In this study, the growth and lipid accumulation of filamentous microalgae Xanthonema hormidioides under different temperatures (5, 7, 10, 15, 20, 25, 27 and 30 °C) and initial nitrogen concentrations (3, 9, 18 mM) were investigated, and its adaptive mechanisms of tolerance to low temperature and nitrogen stress were analysis by proteomics. Results The optimum temperature range for the growth of X. hormidioides was between 15 and 20 °C, and the algal cells had slow growth rate at 5 °C and could not survive at 30 °C. The maximum biomass concentration was 11.73 g L−1 under the temperature of 20 °C, and the highest total lipid content was 56.63% of dry weight. Low temperature did not change the fatty acids profiles but promoted the accumulation of unsaturated fatty acids of X. hormidioides. The maximum contents of palmitoleic acid, eicosapentaenoic acid and total fatty acid were 23.64%, 2.49% and 41.14% of dry weight, respectively. Proteomics was performed under three temperature (7, 15, 25 °C), two nitrogen concentrations (3 and 18 mM) and two cultivation times (day 3 and 12). A total of 6503 proteins were identified. In the low temperature, photosynthesis-related proteins were down-regulated to protect the photosynthetic apparatus. The up-regulation of key enzymes DGAT and PDAT demonstrated the accumulation of TAGs under low nitrogen treatment. The proteins related to ribosome, phosphatidylinositol signaling system, antioxidant system and cold shock proteins (CSPs) in X. hormidioides were co-upregulated under the treatment of low temperature, which can alleviate the damages induced by temperature stress and maintain the normal growth and metabolism of algal cells. Conclusions X. hormidioides is a psychrotolerant microalga. It is an oleaginous filamentous microalga containing hyper palmitoleic acid and a certain amount of eicosapentaenoic acid with great potential for biofuel development, as well as for applications in nutritional health products and other industries.

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“…Microalgal strain Synechocystis sp. PAK13, isolated by Elsayed et al [13], was cultivated on Wuxal liquid media (WM; Wilhelm Haug GmbH & Co. KG®) in 250‐ml Erlenmeyer flasks at 28 ± 2°C, with a light‐dark cycle of 10 h of light (light intensity 30.4 µmol m −2 s −1 ) followed by 14 h in the dark. The growth curve was monitored by measuring optical density at 700 nm and counting cell number with a hemocytometer.…”

Section: Methodsmentioning

confidence: 99%

Recombinant overexpression of the Escherichia coli acetyl‐CoA carboxylase gene in Synechocystis sp. boosts lipid production

et al. 2021

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Microalgae have received continued attention as a potential source for biofuel production. However, the lack of suitable strains that provide a lipid‐rich biomass and tolerate harsh condition inhibits their industrial application. This report describes an effort to transform Synechocystis sp. with genes encoding acetyl‐CoA carboxylase (ACC), a key regulatory enzyme in the lipogenesis pathway, from the white mustard plant (Sinapis alba) and the bacterium Escherichia coli DH5α using chitosan nanoparticles. Although a recombinant plasmid encoding S. alba ACC failed to express, successful transformation was achieved with a recombinant plasmid encoding E. coli DH5α ACC. The successful transformant, Synechocystis sp. PAK13, exhibited increased ACC expression compared with its wild‐type parent (11.8 vs. 7.2 ng), which significantly increased its lipid content (by 3.6‐fold). Synechocystis sp. PAK13 also exhibited a significant (20%) reduction in photosynthetic pigments, a 1.52‐fold higher glucose content and a 3.5‐fold lower sucrose content than the wild‐type. In conclusion, this report introduces a useful strategy to overexpress the ACC gene in microalgae, creating strains with improved lipid production that are suited to industrial applications.

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Imaging the accumulated intracellular microalgal lipids as a response to temperature stress

Cited by 18 publications

References 53 publications

Nile Red assay development for the estimation of neutral lipids in Chlorella emersonii and Pseudokirchneriella subcapitata

Nile Red assay development for the estimation of neutral lipids in Chlorella emersonii and Pseudokirchneriella subcapitata

The growth, lipid accumulation and adaptation mechanism in response to variation of temperature and nitrogen supply in psychrotrophic filamentous microalga Xanthonema hormidioides (Xanthophyceae)

Recombinant overexpression of the Escherichia coli acetyl‐CoA carboxylase gene in Synechocystis sp. boosts lipid production

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