Light and photosynthetic microalgae: A review of cellular- and molecular-scale optical processes

Lehmuskero, Anni Maria; Chauton, Matilde Skogen; Boström, Tobias

doi:10.1016/j.pocean.2018.09.002

Cited by 105 publications

(54 citation statements)

References 175 publications

(221 reference statements)

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“…Wild-type Euglena gracilis showed distinct colored features under brightfield microscopy, particularly the green chloroplasts (Figure 2A). Absorbance and emission spectroscopy showed peaks consistent with chlorophyll and carotenoids [31,32] ( Figures 2C,D). Streptomycin-bleached Euglena appeared hollowed under brightfield, with transparent regions (Figure 2B).…”

Section: Euglena Appearance and Spectramentioning

confidence: 99%

Multiwavelength Digital Holographic Imaging and Phase Unwrapping of Protozoa Using Custom Fiji Plug-ins

et al. 2019

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Multiwavelength digital holographic microscopy (DHM) has been used to improve phase reconstructions of digital holograms by reducing 2π phase ambiguities. However, most samples used as test images have been solid or adhered to a surface, making it easy to determine focal planes and correct for chromatic aberration. In this study we apply 3-wavelength off-axis DHM to swimming protozoa containing distinct spectral features such as chlorophyll and carotenoids. We reconstruct the holograms into amplitude and phase images using the angular spectrum method. Methods for noise subtraction, chromatic aberration correction, and image registration are presented for both amplitude and phase. Approaches to phase unwrapping are evaluated and compared to expected results from simulated holograms. The algorithms used are implemented in plug-ins using the open source Fiji platform and are available for use, significantly expanding the open-source software available for DHM.

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Section: Euglena Appearance and Spectramentioning

confidence: 99%

Multiwavelength Digital Holographic Imaging and Phase Unwrapping of Protozoa Using Custom Fiji Plug-ins

et al. 2019

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“…However, a strikingly different pattern was observed with fluorometry: between the first and second day of the time course, the total fluorescence soared from below 1kRFU to 32 kRFU. Daily observation of the microplates by the experimenters ruled out the possibility that such a sudden overnight increase corresponded to a commensurate biomass increase, and was therefore attributed mainly the induction of chlorophyll synthesis due to photoacclimation [see 25,26]. Subsequently, the fluorescence readings remained at least one order of magnitude higher in the 20 µmol.m -2 .s -1 condition compared to the low light control until the end of the experiment (Fig.…”

Section: Non-invasive Monitoring Of Algal Growthmentioning

confidence: 99%

Parallelisable non-invasive biomass, fitness and growth measurement of macroalgae and other protists with nephelometry

et al. 2020

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With the exponential development of algal aquaculture and blue biotechnology, there is a strong demand for simple, inexpensive, high-throughput, quantitative phenotyping assays to measure the biomass, growth and fertility of algae and other marine protists. Here, we validate nephelometry, a method that relies on measuring the scattering of light by particles in suspension, as a non-invasive tool to measure in real-time the biomass of aquatic microorganisms , such as microalgae, filamentous algae, as well as non-photosynthetic protists. Nephelometry is equally applicable to optic density and chlorophyll fluorescence measurements for the quantification of some microalgae, but outperforms other spectroscopy methods to quantify the biomass of biofilm-forming and filamentous algae, highly pigmented species and non-photosynthetic eukaryotes. Thanks to its insensitivity to the sample's pigmentation, nephelometry is also the method of choice when chlorophyll content varies between samples or time points, for example due to abiotic stress or pathogen infection. As examples, we illustrate how nephelometry can be combined with fluorometry or image analysis to monitor the quantity and time-course of spore release in fertile kelps or the progression of symptoms in diseased algal cultures.

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“…Exposure to wavelengths between 500 and 600 nm (so called green gap in literature) alone generally causes a lower level of growth rate than that under either blue or red lights. Therefore, green LED s were often found to be highly unsuitable for microalgae if used without additional light sources (Itoh et al, 2014; Lehmuskeroa, Skogen Chautonb, & Boström, 2018; Schulze, Barreira Luísa, Pereira, Perales José, & Varela, 2014). In contrast, some studies have reported that ‘the green gap’ waveband is also an effective radiation to promote photosynthesis of higher plants and microalgae (Johkan, Shoji, Goto, Hahida, & Yoshihara, 2012; Mohsenpour & Willoughby, 2013; Terashima, Fujita, Inoue, Chow, & Oguchi, 2009).…”

Section: Discussionmentioning

confidence: 99%

“…The explanation is that in the cells, pigments are contained in chloroplasts within an intricate molecular environment. The constituents of the cells, such as proteins, lipids, pigments and carbohydrates, have their own optical properties that reduce the energy of photons reaching the PSII reaction centre (Johnsen & Sakshaug, 2007; Lehmuskeroa et al, 2018).…”

Section: Discussionmentioning

confidence: 99%

Analysis of light absorption and photosynthetic activity by Isochrysis galbana under different light qualities

Liu

2020

Aquac Res

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The effect of light qualities, for example white light (WL), blue light (BL), red light (RL) and green light (GL), respectively, provided by the LEDs on the growth, pigment content, light absorption and chlorophyll fluorescence parameters of Isochrysis galbana strain IOAC724S was measured. The growth rate of algae exposed to GL was not significantly different from that of WL, but was significantly higher than that of blue light (BL) or red light (RL). These four light colours were all efficiently absorbed by algal cells, with an absorption rate up to 92%-93%. The light absorbed by pigments contributes only part of the light absorbed by cells, ranging from 8.3% (at RL) to 59.7% (at BL). Among the monochromatic light, the highest light absorption was obtained in cells cultivated at BL, but the photochemical reaction was lowered. No positive effect of monochromatic RL was found. Cells cultivated at BL and RL were, respectively, restricted by down-regulated photosynthetic efficiency and sufficient light absorption; meanwhile, GL showed a dramatic increase in photosynthetic efficiency, associated with a light absorption close to that for cells exposed to WL (both at 30.6%), suggesting that GL promotes the photosynthesis of I. galbana by balancing the light absorption and utilization.

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Light and photosynthetic microalgae: A review of cellular- and molecular-scale optical processes

Cited by 105 publications

References 175 publications

Multiwavelength Digital Holographic Imaging and Phase Unwrapping of Protozoa Using Custom Fiji Plug-ins

Multiwavelength Digital Holographic Imaging and Phase Unwrapping of Protozoa Using Custom Fiji Plug-ins

Parallelisable non-invasive biomass, fitness and growth measurement of macroalgae and other protists with nephelometry

Analysis of light absorption and photosynthetic activity by Isochrysis galbana under different light qualities

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