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Rammel T, Nagarkar M, Palenik B. Temporal and spatial diversity and abundance of cryptophytes in San Diego coastal waters. JOURNAL OF PHYCOLOGY 2024; 60:668-684. [PMID: 38721968 DOI: 10.1111/jpy.13451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 11/02/2023] [Accepted: 01/29/2024] [Indexed: 06/12/2024]
Abstract
Cryptophytes (class Cryptophyceae) are bi-flagellated eukaryotic protists with mixed nutritional modes and cosmopolitan distribution in aquatic environments. Despite their ubiquitous presence, their molecular diversity is understudied in coastal waters. Weekly 18S rRNA gene amplicon sequencing at the Scripps Institution of Oceanography pier (La Jolla, California) in 2016 revealed 16 unique cryptophyte amplicon sequence variants (ASVs), with two dominant "clade 4" ASVs. The diversity of cryptophytes was lower than what is often seen in other phytoplankton taxa. One ASV represented a known Synechococcus grazer, while the other one appeared not to have cultured representatives and an unknown potential for mixotrophy. These two dominant ASVs were negatively correlated, suggesting possible niche differentiation. The cryptophyte population in nearby San Diego Bay was surveyed in 2019 and showed the increasing dominance of a different clade 4 ASV toward the back of the bay where conditions are warmer, saltier, and shallower relative to other areas in the bay. An ASV representing a potentially chromatically acclimating cryptophyte species also suggested that San Diego Bay exerts differing ecological selection pressures than nearby coastal waters. Cryptophyte and Synechococcus cell abundance at the SIO Pier from 2011 to 2017 showed that cryptophytes were consistently present and had a significant correlation with Synechococcus abundance, but no detectable seasonality. The demonstrated mixotrophy of some cryptophytes suggests that grazing on these and perhaps other bacteria is important for their ecological success. Using several assumptions, we calculated that cryptophytes could consume up to 44% (average 6%) of the Synechococcus population per day. This implies that cryptophytes could significantly influence Synechococcus abundance.
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Affiliation(s)
- Tristin Rammel
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
| | - Maitreyi Nagarkar
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
| | - Brian Palenik
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
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2
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Zhang S, Si L, Su X, Zhao X, An X, Li M. Growth phase-dependent reorganization of cryptophyte photosystem I antennae. Commun Biol 2024; 7:560. [PMID: 38734819 PMCID: PMC11088674 DOI: 10.1038/s42003-024-06268-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Accepted: 04/30/2024] [Indexed: 05/13/2024] Open
Abstract
Photosynthetic cryptophytes are eukaryotic algae that utilize membrane-embedded chlorophyll a/c binding proteins (CACs) and lumen-localized phycobiliproteins (PBPs) as their light-harvesting antennae. Cryptophytes go through logarithmic and stationary growth phases, and may adjust their light-harvesting capability according to their particular growth state. How cryptophytes change the type/arrangement of the photosynthetic antenna proteins to regulate their light-harvesting remains unknown. Here we solve four structures of cryptophyte photosystem I (PSI) bound with CACs that show the rearrangement of CACs at different growth phases. We identify a cryptophyte-unique protein, PsaQ, which harbors two chlorophyll molecules. PsaQ specifically binds to the lumenal region of PSI during logarithmic growth phase and may assist the association of PBPs with photosystems and energy transfer from PBPs to photosystems.
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Affiliation(s)
- Shumeng Zhang
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Long Si
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xiaodong Su
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Xuelin Zhao
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Xiaomin An
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Mei Li
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
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3
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Merritt KA, Richardson TL. Variability in spectral absorption within cryptophyte phycobiliprotein types. JOURNAL OF PHYCOLOGY 2024; 60:528-540. [PMID: 38456338 DOI: 10.1111/jpy.13439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 01/29/2024] [Accepted: 02/05/2024] [Indexed: 03/09/2024]
Abstract
Cryptophytes are known to vary widely in coloration among species. These differences in color arise primarily from the presence of phycobiliprotein accessory pigments. There are nine defined cryptophyte phycobiliprotein (Cr-PBP) types, named for their wavelength of maximal absorbance. Because Cr-PBP type has traditionally been regarded as a categorical trait, there is a paucity of information about how spectral absorption characteristics of Cr-PBPs vary among species. We investigated variability in primary and secondary peak absorbance wavelengths and full width at half max (FWHM) values of spectra of Cr-PBPs extracted from 75 cryptophyte strains (55 species) grown under full spectrum irradiance. We show that there may be substantial differences in spectral shapes within Cr-PBP types, with Cr-Phycoerythrin (Cr-PE) 545 showing the greatest variability with two, possibly three, subtypes, while Cr-PE 566 spectra were the least variable, with only ±1 nm of variance around the mean absorbance maximum of 565 nm. We provide additional criteria for classification in cases where the wavelength of maximum absorbance alone is not definitive. Variations in spectral characteristics among strains containing the same presumed Cr-PBP type may indicate differing chromophore composition and/or the presence of more than one Cr-PBP in a single cryptophyte species.
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Affiliation(s)
- Kristiaän A Merritt
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina, USA
| | - Tammi L Richardson
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina, USA
- School of the Earth, Ocean & Environment, University of South Carolina, Columbia, South Carolina, USA
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4
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Schomaker RA, Richardson TL, Dudycha JL. Consequences of light spectra for pigment composition and gene expression in the cryptophyte Rhodomonas salina. Environ Microbiol 2023; 25:3280-3297. [PMID: 37845005 DOI: 10.1111/1462-2920.16523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 09/28/2023] [Indexed: 10/18/2023]
Abstract
Algae with a more diverse suite of pigments can, in principle, exploit a broader swath of the light spectrum through chromatic acclimation, the ability to maximize light capture via plasticity of pigment composition. We grew Rhodomonas salina in wide-spectrum, red, green, and blue environments and measured how pigment composition differed. We also measured expression of key light-capture and photosynthesis-related genes and performed a transcriptome-wide expression analysis. We observed the highest concentration of phycoerythrin in green light, consistent with chromatic acclimation. Other pigments showed trends inconsistent with chromatic acclimation, possibly due to feedback loops among pigments or high-energy light acclimation. Expression of some photosynthesis-related genes was sensitive to spectrum, although expression of most was not. The phycoerythrin α-subunit was expressed two-orders of magnitude greater than the β-subunit even though the peptides are needed in an equimolar ratio. Expression of genes related to chlorophyll-binding and phycoerythrin concentration were correlated, indicating a potential synthesis relationship. Pigment concentrations and expression of related genes were generally uncorrelated, implying post-transcriptional regulation of pigments. Overall, most differentially expressed genes were not related to photosynthesis; thus, examining associations between light spectrum and other organismal functions, including sexual reproduction and glycolysis, may be important.
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Affiliation(s)
| | - Tammi L Richardson
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina, USA
- School of the Earth, Ocean, & Environment, University of South Carolina, Columbia, South Carolina, USA
| | - Jeffry L Dudycha
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina, USA
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5
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Rathbone HW, Laos AJ, Michie KA, Iranmanesh H, Biazik J, Goodchild SC, Thordarson P, Green BR, Curmi PMG. Molecular dissection of the soluble photosynthetic antenna from the cryptophyte alga Hemiselmis andersenii. Commun Biol 2023; 6:1158. [PMID: 37957226 PMCID: PMC10643455 DOI: 10.1038/s42003-023-05508-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 10/25/2023] [Indexed: 11/15/2023] Open
Abstract
Cryptophyte algae have a unique phycobiliprotein light-harvesting antenna that fills a spectral gap in chlorophyll absorption from photosystems. However, it is unclear how the antenna transfers energy efficiently to these photosystems. We show that the cryptophyte Hemiselmis andersenii expresses an energetically complex antenna comprising three distinct spectrotypes of phycobiliprotein, each composed of two αβ protomers but with different quaternary structures arising from a diverse α subunit family. We report crystal structures of the major phycobiliprotein from each spectrotype. Two-thirds of the antenna consists of open quaternary form phycobiliproteins acting as primary photon acceptors. These are supplemented by a newly discovered open-braced form (~15%), where an insertion in the α subunit produces ~10 nm absorbance red-shift. The final components (~15%) are closed forms with a long wavelength spectral feature due to substitution of a single chromophore. This chromophore is present on only one β subunit where asymmetry is dictated by the corresponding α subunit. This chromophore creates spectral overlap with chlorophyll, thus bridging the energetic gap between the phycobiliprotein antenna and the photosystems. We propose that the macromolecular organization of the cryptophyte antenna consists of bulk open and open-braced forms that transfer excitations to photosystems via this bridging closed form phycobiliprotein.
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Affiliation(s)
- Harry W Rathbone
- School of Physics, The University of New South Wales, Sydney, NSW, 2052, Australia
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia
- UMR144 Cell Biology and Cancer, Institut Curie, Paris, 75005, France
| | - Alistair J Laos
- UNSW RNA Institute and School of Chemistry, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Katharine A Michie
- School of Physics, The University of New South Wales, Sydney, NSW, 2052, Australia
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia
- Mark Wainwright Analytical Centre, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Hasti Iranmanesh
- School of Physics, The University of New South Wales, Sydney, NSW, 2052, Australia
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Joanna Biazik
- Mark Wainwright Analytical Centre, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Sophia C Goodchild
- School of Molecular Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Pall Thordarson
- UNSW RNA Institute and School of Chemistry, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Beverley R Green
- Department of Botany, University of British Columbia, Vancouver, BC, Canada
| | - Paul M G Curmi
- School of Physics, The University of New South Wales, Sydney, NSW, 2052, Australia.
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia.
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Xu S, Li G, He C, Huang Y, Yu D, Deng H, Tong Z, Wang Y, Dupuy C, Huang B, Shen Z, Xu J, Gong J. Diversity, community structure, and quantity of eukaryotic phytoplankton revealed using 18S rRNA and plastid 16S rRNA genes and pigment markers: a case study of the Pearl River Estuary. MARINE LIFE SCIENCE & TECHNOLOGY 2023; 5:415-430. [PMID: 37637251 PMCID: PMC10449762 DOI: 10.1007/s42995-023-00186-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 06/11/2023] [Indexed: 08/29/2023]
Abstract
Understanding consistencies and discrepancies in characterizing diversity and quantity of phytoplankton is essential for better modeling ecosystem change. In this study, eukaryotic phytoplankton in the Pearl River Estuary, South China Sea were investigated using nuclear 18S rRNA and plastid 16S or 23S rRNA genes and pigment analysis. It was found that 18S abundance poorly explained the variations in total chlorophyll a (Chl-a). However, the ratios of log-transformed 18S abundance to Chl-a in the major phytoplankton groups were generally environment dependent, suggesting that the ratio has potential as an indicator of the physiological state of phytoplankton. The richness of 18S-based operational taxonomic units was positively correlated with the richness of 16S-based amplicon sequence variants of the whole phytoplankton community, but insignificant or weak for individual phytoplankton groups. Overall, the 18S based, rather than the 16S based, community structure had a greater similarity to pigment-based estimations. Relative to the pigment data, the proportion of haptophytes in the 18S dataset, and diatoms and cryptophytes in the 16S dataset, were underestimated. This study highlights that 18S metabarcoding tends to reflect biomass-based community organization of eukaryotic phytoplankton. Because there were lower copy numbers of plastid 16S than 18S per genome, metabarcoding of 16S probably approximates cell abundance-based community organization. Changes in biomass organization of the pigment-based community were sensitive to environmental changes. Taken together, multiple methodologies are recommended to be applied to more accurately profile the diversity and community composition of phytoplankton in natural ecosystems. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-023-00186-x.
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Affiliation(s)
- Shumin Xu
- School of Marine Sciences, Sun Yat-Sen University (Zhuhai Campus), and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000 China
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Guangzhou, 510006 China
| | - Guihao Li
- School of Marine Sciences, Sun Yat-Sen University (Zhuhai Campus), and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000 China
| | - Cui He
- School of Marine Sciences, Sun Yat-Sen University (Zhuhai Campus), and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000 China
| | - Yi Huang
- School of Marine Sciences, Sun Yat-Sen University (Zhuhai Campus), and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000 China
| | - Dan Yu
- School of Marine Sciences, Sun Yat-Sen University (Zhuhai Campus), and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000 China
| | - Huiwen Deng
- School of Marine Sciences, Sun Yat-Sen University (Zhuhai Campus), and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000 China
| | - Zhuyin Tong
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102 China
| | - Yichong Wang
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102 China
| | - Christine Dupuy
- BIOFEEL, UMRi LIENSs, La Rochelle Université/CNRS, La Rochelle, France
| | - Bangqin Huang
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361102 China
| | - Zhuo Shen
- School of Marine Sciences, Sun Yat-Sen University (Zhuhai Campus), and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000 China
| | - Jie Xu
- Centre for Regional Oceans, Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau, China
| | - Jun Gong
- School of Marine Sciences, Sun Yat-Sen University (Zhuhai Campus), and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000 China
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Guangzhou, 510006 China
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Michie KA, Harrop SJ, Rathbone HW, Wilk KE, Teng CY, Hoef‐Emden K, Hiller RG, Green BR, Curmi PMG. Molecular structures reveal the origin of spectral variation in cryptophyte light harvesting antenna proteins. Protein Sci 2023; 32:e4586. [PMID: 36721353 PMCID: PMC9951199 DOI: 10.1002/pro.4586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/24/2023] [Accepted: 01/27/2023] [Indexed: 02/02/2023]
Abstract
In addition to their membrane-bound chlorophyll a/c light-harvesting antenna, the cryptophyte algae have evolved a unique phycobiliprotein antenna system located in the thylakoid lumen. The basic unit of this antenna consists of two copies of an αβ protomer where the α and β subunits scaffold different combinations of a limited number of linear tetrapyrrole chromophores. While the β subunit is highly conserved, encoded by a single plastid gene, the nuclear-encoded α subunits have evolved diversified multigene families. It is still unclear how this sequence diversity results in the spectral diversity of the mature proteins. By careful examination of three newly determined crystal structures in comparison with three previously obtained, we show how the α subunit amino acid sequences control chromophore conformations and hence spectral properties even when the chromophores are identical. Previously we have shown that α subunits control the quaternary structure of the mature αβ.αβ complex (either open or closed), however, each species appeared to only harbor a single quaternary form. Here we show that species of the Hemiselmis genus contain expressed α subunit genes that encode both distinct quaternary structures. Finally, we have discovered a common single-copy gene (expressed into protein) consisting of tandem copies of a small α subunit that could potentially scaffold pairs of light harvesting units. Together, our results show how the diversity of the multigene α subunit family produces a range of mature cryptophyte antenna proteins with differing spectral properties, and the potential for minor forms that could contribute to acclimation to varying light regimes.
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Affiliation(s)
- Katharine A. Michie
- School of PhysicsThe University of New South WalesSydneyNew South WalesAustralia
- School of Biotechnology and Biomolecular SciencesThe University of New South WalesSydneyNew South WalesAustralia
- Mark Wainwright Analytical CentreUniversity of New South WalesSydneyNew South WalesAustralia
| | - Stephen J. Harrop
- School of PhysicsThe University of New South WalesSydneyNew South WalesAustralia
- MX Beamlines, Australian SynchrotronClaytonVictoriaAustralia
| | - Harry W. Rathbone
- School of PhysicsThe University of New South WalesSydneyNew South WalesAustralia
- School of Biotechnology and Biomolecular SciencesThe University of New South WalesSydneyNew South WalesAustralia
| | - Krystyna E. Wilk
- School of PhysicsThe University of New South WalesSydneyNew South WalesAustralia
| | - Chang Ying Teng
- Department of BotanyUniversity of British ColumbiaVancouverCanada
| | | | - Roger G. Hiller
- Department of Biological SciencesMacquarie UniversitySydneyNew South WalesAustralia
| | | | - Paul M. G. Curmi
- School of PhysicsThe University of New South WalesSydneyNew South WalesAustralia
- School of Biotechnology and Biomolecular SciencesThe University of New South WalesSydneyNew South WalesAustralia
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Promising Biomolecules with High Antioxidant Capacity Derived from Cryptophyte Algae Grown under Different Light Conditions. BIOLOGY 2022; 11:biology11081112. [PMID: 35892969 PMCID: PMC9331842 DOI: 10.3390/biology11081112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 07/21/2022] [Accepted: 07/22/2022] [Indexed: 11/17/2022]
Abstract
The accumulation and production of biochemical compounds in microalgae are influenced by available light quality and algal species-specific features. In this study, four freshwater cryptophyte strains (Cryptomonas ozolinii, C. pyrenoidifera, C. curvata, and C. sp. (CPCC 336)) and one marine strain (Rhodomonas salina) were cultivated under white (control), blue, and green (experimental conditions) lights. Species-specific responses to light quality were detected, i.e., the color of light significantly affected cryptophyte biomass productivity and biochemical compositions, but the optimal light for the highest chemical composition with high antioxidant capacity was different for each algal strain. Overall, the highest phycoerythrin (PE) content (345 mg g−1 dry weight; DW) was reached by C. pyrenoidifera under green light. The highest phenolic (PC) contents (74, 69, and 66 mg g−1 DW) were detected in C. curvata under control conditions, in C. pyrenoidifera under green light, and in C. ozolinii under blue light, respectively. The highest exopolysaccharide (EPS) content (452 mg g−1 DW) was found in C. curvata under the control light. In terms of antioxidant activity, the biochemical compounds from the studied cryptophytes were highly active, with IC50 -values < 50 µg mL−1. Thus, in comparison to well-known commercial microalgal species, cryptophytes could be considered a possible candidate for producing beneficial biochemical compounds.
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Spangler LC, Yu M, Jeffrey PD, Scholes GD. Controllable Phycobilin Modification: An Alternative Photoacclimation Response in Cryptophyte Algae. ACS CENTRAL SCIENCE 2022; 8:340-350. [PMID: 35350600 PMCID: PMC8949638 DOI: 10.1021/acscentsci.1c01209] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Indexed: 05/29/2023]
Abstract
Cryptophyte algae are well-known for their ability to survive under low light conditions using their auxiliary light harvesting antennas, phycobiliproteins. Mainly acting to absorb light where chlorophyll cannot (500-650 nm), phycobiliproteins also play an instrumental role in helping cryptophyte algae respond to changes in light intensity through the process of photoacclimation. Until recently, photoacclimation in cryptophyte algae was only observed as a change in the cellular concentration of phycobiliproteins; however, an additional photoacclimation response was recently discovered that causes shifts in the phycobiliprotein absorbance peaks following growth under red, blue, or green light. Here, we reproduce this newly identified photoacclimation response in two species of cryptophyte algae and elucidate the origin of the response on the protein level. We compare isolated native and photoacclimated phycobiliproteins for these two species using spectroscopy and mass spectrometry, and we report the X-ray structures of each phycobiliprotein and the corresponding photoacclimated complex. We find that neither the protein sequences nor the protein structures are modified by photoacclimation. We conclude that cryptophyte algae change one chromophore in the phycobiliprotein β subunits in response to changes in the spectral quality of light. Ultrafast pump-probe spectroscopy shows that the energy transfer is weakly affected by photoacclimation.
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Affiliation(s)
- Leah C. Spangler
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Mina Yu
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Philip D. Jeffrey
- Department
of Molecular Biology, Princeton University, Princeton, New Jersey 08544, United States
| | - Gregory D. Scholes
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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