Light modulation of biomass and macromolecular composition of the diatom Skeletonema marinoi

Chandrasekaran, Raghu; Barra, Lucia; Carillo, Sara; Caruso, Tonino; Corsaro, Maria Michela; Piaz, Fabrizio Dal; Graziani, Giulia; Corato, Federico; Pepe, Debora; Manfredonia, Alessandro; Orefice, Ida; Ruban, Alexander V.; Brunet, Christophe

doi:10.1016/j.jbiotec.2014.10.016

Cited by 25 publications

(24 citation statements)

References 31 publications

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“…For example, Orefice et al [62] showed that the fluctuation of red light on blue light spectral distribution affected the metabolic state of cells via increase in non-photochemical quenching and ultimately promoting an increase in carbohydrates, glycolipids, and saturated fatty acids in Skeletonema marinoi [62]. In another study, it was observed that different doses of blue wavelengths cause significant alternations in the growth cycle of Skeletonema marinoi [63]. The change in the growth pattern and biochemical composition can be referred to the ability of diatoms and microalgae to finely balance the light-harvesting and photoprotective capacity [64][65][66][67].…”

Section: C:dmentioning

confidence: 99%

Red Light Variation an Effective Alternative to Regulate Biomass and Lipid Profiles in Phaeodactylum tricornutum

et al. 2020

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Marine water diatom Phaeodactylum tricornutum is a photosynthetic organism that is known to respond to the changing light environment and adapt to different temperatures to prevent photoinhibition and maintain its metabolic functions. The objective of the present study was to test whether light shift variations in different growth phases impact the growth and lipid metabolism of P. tricornutum. Thus, we investigated R exposure in different growth phases to find the most effective light shift condition. The results showed that substituting white light (W) by red light (R) under autotrophic conditions, a condition called red shift (RS), increased biomass and lipid content compared to levels found under continuous W or R exposure alone. We observed an increase by 2-fold biomass and 2.3-fold lipid content in RS as compared to W. No significant change was observed in the morphology of lipid droplets, but the fatty acid (FA) composition was altered. Specifically, polyunsaturated FAs were increased, whereas monounsaturated FAs decreased in P. tricornutum grown in RS compared to W control. Therefore, we propose that a light shift during the beginning of the stationary phase is a low-cost cultivation strategy to boost the total biomass and lipids in P. tricornutum.Appl. Sci. 2020, 10, 2531 2 of 18 for the high production of desired bioactive molecules. Therefore, light should be provided with specific spectral components, intensity, and duration. Multiple ecophysiological studies have been published reporting on the distinct behaviors of different diatoms and algae in response to variations in light [4,5]. It has been shown that light quality has an impact on chloroplast migration and on the light acclimation reactions of photosynthesis [6,7]. Red light has been linked to stimulating growth, ethylene production [8], lipid accumulation [7], and increasing thylakoid stacking [6]. have suggested the involvement of phytochromes in increasing the intracellular nitrate content on exposure to red light for short periods altering the overall cellular nitrate content. Recent discoveries in genomics have revealed exciting information on phytochromes, blue-light sensing cryptochromes, and aureochromes [10]. In a study by Jungandreas et al. [11], it has been reported that P. tricornutum cells acclimated to both red and blue light have comparable metabolite profiles, but drastic changes in metabolites and carbon partitioning was observed under red to blue light shift. In addition, various interdisciplinary studies have shown that light perceived by the red-light receptor (phytochromes) can regulate nutrient metabolism, cellular events, and signaling cascades [12]. These discoveries are still in progress and much remains unknown, but these studies can be explored for application-based diatom experiments such as developing low-cost cultivation technology or efficient bioreactors.In both culture medium and natural water bodies, light (intensity, distribution, photoperiod) may vary and will not behave similar to the dissolved salts or nu...

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Section: C:dmentioning

confidence: 99%

Red Light Variation an Effective Alternative to Regulate Biomass and Lipid Profiles in Phaeodactylum tricornutum

et al. 2020

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“…When cell concentrations at T f were not significantly different between controls and copepod tanks, grazing was considered under the detection limit (i.e., <dl in Table 4). Ingestion rates were converted to ng Chl a ind −1 d −1 using a literature-based mean value of 0.10 pg Chl a cell −1 for S. marinoi (Norici et al, 2011;Chandrasekaran et al, 2014;Orefice et al, 2016;Smerilli et al, 2019) and 0.35 pg Chl a cell −1 for C. neogracile (unpublished data from González-Fernández et al, 2019).…”

Section: Specific Growth Rate and Grazing Parametersmentioning

confidence: 99%

Copepod Grazing Influences Diatom Aggregation and Particle Dynamics

et al. 2019

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In marine ecosystems, carbon export is driven by particle flux which is modulated by aggregation, remineralization, and grazing processes. Zooplankton contribute to the sinking flux through the egestion of fast sinking fecal pellets but may also attenuate the flux by tearing apart phytoplankton aggregates into small pieces through swimming activity or direct ingestion. Freely suspended cells, artificial monospecific aggregates from two different diatom species (Chaetoceros neogracile and Skeletonema marinoi) and natural aggregates of Melosira sp. were independently incubated with five different copepod species (Acartia clausi, Temora longicornis, Calanus helgolandicus, Euterpina acutifrons, and Calanus hyperboreus). During the grazing experiments initiated with free diatoms, E. acutifrons feeding activity evidenced by ingestion rates of 157 ± 155 ng Chl a ind −1 d −1 , induced a significant increase of S. marinoi aggregation. Transparent exopolymeric particles (TEP) production was only slightly boosted by the presence of grazers and turbulences created by swimming may be the main trigger of the aggregation processes. All copepods studied were able to graze on aggregates and quantitative estimates led to chlorophyll a ingestion rates (expressed in Chla a equivalent, i.e., the sum of chlorophyll a and pheopigments in their guts) ranging from 4 to 23 ng Chl a eq ind −1 d −1 . The relation between equivalent spherical diameters (ESDs) and sinking velocities of the aggregates did not significantly change after grazing, suggesting that copepod grazing did not affect aggregate density as also shown by Si:C and C:N ratios. Three main trends in particle dynamics could be identified and further linked to the copepod feeding behavior and the size ratio between prey and predators:(1) Fragmentation of S. marinoi aggregates by the cruise feeder T. longicornis and of Melosira sp. aggregates by C. hyperboreus at prey to predator size ratios larger than 15; (2) no change of particle dynamics in the presence of the detritic cruise feeder E. acutifrons; and finally (3) re-aggregation of C. neogracile and S. marinoi aggregates when the two filter feeders A. clausi and C. helgolandicus were grazing on aggregate at prey to predator size ratios lower than 10. Aggregation of freely suspended cells or small aggregates was facilitated by turbulence resulting from active swimming of small copepods. However, stronger turbulence created by larger cruise feeders copepods prevent aggregate formation and even made them vulnerable to breakage.

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“…The cells were pre-acclimated to photoperiod of 12 h:12 h light:dark, and the diurnal phase consisted in a sinusoidal blue light course, characterized by a gradual light intensity increase from dawn to midday (6 h) peaking at 150 mmol photons s 21 m 22 , and then a gradual light decrease from midday to sunset (6 h). This pre-acclimation setup has been selected following the results obtained by Chandrasekaran et al, (2014), who stated that this condition provides the optimal physiological health in S. marinoi enhancing growth capacity and metabolic state. Growth rate during the exponential phase was %0.82 d 21 .…”

Section: Experimental Strategy and Samplingmentioning

confidence: 99%

“…Skeletonema marinoi was used as model due to its high capability of growth and potential relevant role in biotechnological applications (Chandrasekaran et al ., ), as well as for all the information already available on the biology and photophysiology of this species (Chandrasekaran et al ., ; Orefice et al , ). S. marinoi is a cosmopolitan centric diatom, very abundant during spring bloom in temperate waters when its concentration can reach millions of cells per litre in the photic zone.…”

Section: Introductionmentioning

confidence: 99%

“…Next-generation photobioreactors allow the selection of specific conditions according to the physiological and growth characteristics of each individual microalgal species. One of the most important parameters that modulates growth and productivity of photosynthetic microorganisms is light (Perrine et al, 2012;Chandrasekaran et al, 2014). In aquatic ecosystems light is the most changeable parameter, displaying huge variability of the photon flux density (PFD) and spectral composition as a result of the vertical gradient, time of the day and the absorptive and scattering processes of the water itself.…”

Section: Introductionmentioning

confidence: 99%

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Photoprotective and antioxidant responses to light spectrum and intensity variations in the coastal diatom Skeletonema marinoi

Smerilli

Orefice

Corato

et al. 2016

Environmental Microbiology

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Photosynthesis is known to produce reactive oxygen species together with the transformation of light into biochemical energy. To fill the gap of the knowledge on the protective antioxidant network of microalgae, a series of experiments to explore the role of spectral composition and intensity of light in the modulation of the photodefence mechanisms developed by the coastal diatom Skeletonema marinoi were performed. The modulation of the total phenolic content, ascorbic acid and the enzymes glutathione reductase, catalase, ascorbate peroxidase and superoxide dismutase together with xanthophyll cycle and non-photochemical quenching in response to variations in the light environment were analysed. Most of the enzymes' activity was promptly affected by the red light. Yet, the monochromatic high intensity blue light enhanced the synthesis of total phenolic content and ascorbic acid in parallel to the xanthophyll cycle activity. This study reveals the dual effects of spectral composition and intensity of light on the modulation of photoprotective mechanisms. Diatoms developed a complementary and/or alternative tuning processes to cope with the variable light environment they experience in the water column. They also provided valuable insights into light manipulation regimes for diatom cultivation that will help to maximize production of bioactive molecules.

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Light modulation of biomass and macromolecular composition of the diatom Skeletonema marinoi

Cited by 25 publications

References 31 publications

Red Light Variation an Effective Alternative to Regulate Biomass and Lipid Profiles in Phaeodactylum tricornutum

Red Light Variation an Effective Alternative to Regulate Biomass and Lipid Profiles in Phaeodactylum tricornutum

Copepod Grazing Influences Diatom Aggregation and Particle Dynamics

Photoprotective and antioxidant responses to light spectrum and intensity variations in the coastal diatom Skeletonema marinoi

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