Chilling out: the evolution and diversification of psychrophilic algae with a focus on Chlamydomonadales

Cvetkovska, Marina; Hüner, Norman P. A.; Smith, David Roy

doi:10.1007/s00300-016-2045-4

Cited by 51 publications

(45 citation statements)

References 121 publications

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“…Primary production in many cold ecosystems is mainly dependent on photosynthetic microorganisms, including eukaryotic algae (Morgan-Kiss et al, 2006). Many of these organisms are obligate cold-temperature extremophiles (psychrophiles), defined as being metabolically active and able to reproduce at temperatures permanently close to the freezing point of water and unable to tolerate more moderate (mesophilic) temperatures (≥ 20°C) (Cvetkovska et al, 2017). Cold temperatures place severe physiochemical constraints on crucial aspects of cell function, including water viscosity, membrane fluidity, macromolecule interactions, and enzyme kinetics.…”

Section: Introductionmentioning

confidence: 99%

“…Under laboratory conditions, UWO241 grows optimally at 8°C and low salinity (70 mM), and is unable to grow at temperatures ≥18°C (Morgan et al, 1998;Pocock et al, 2004Pocock et al, , 2007Takizawa et al, 2009;Possmayer et al, 2011). With over two decades of research focused on the biochemistry and biophysics of its photosynthetic apparatus (Morgan-Kiss et al, 2006;Dolhi et al, 2013;Cvetkovska et al, 2017), and a close phylogenetic relationship with other model algae such as Chlamydomonas reinhardtii and Dunaliella salina (Possmayer et al, 2016), UWO241 is emerging as an attractive system for studying how photosynthesis operates at low temperatures. While some aspects of photosynthesis in UWO241 have been studied in detail, researchers have not yet managed to link these features to the function of cold-adapted enzymes.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of photosynthetic ferredoxin from the Antarctic alga Chlamydomonas sp. UWO241 reveals novel features of cold adaptation

et al. 2018

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The objective of this work was to characterize photosynthetic ferredoxin from the Antarctic green alga Chlamydomonas sp. UWO241, a key enzyme involved in distributing photosynthetic reducing power. We hypothesize that ferredoxin possesses characteristics typical of cold-adapted enzymes, namely increased structural flexibility and high activity at low temperatures, accompanied by low stability at moderate temperatures. To address this objective, we purified ferredoxin from UWO241 and characterized the temperature dependence of its enzymatic activity and protein conformation. The UWO241 ferredoxin protein, RNA, and DNA sequences were compared with homologous sequences from related organisms. We provide evidence for the duplication of the main ferredoxin gene in the UWO241 nuclear genome and the presence of two highly similar proteins. Ferredoxin from UWO241 has both high activity at low temperatures and high stability at moderate temperatures, representing a novel class of cold-adapted enzymes. Our study reveals novel insights into how photosynthesis functions in the cold. The presence of two distinct ferredoxin proteins in UWO241 could provide an adaptive advantage for survival at cold temperatures. The primary amino acid sequence of ferredoxin is highly conserved among photosynthetic species, and we suggest that subtle differences in sequence can lead to significant changes in activity at low temperatures.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characterization of photosynthetic ferredoxin from the Antarctic alga Chlamydomonas sp. UWO241 reveals novel features of cold adaptation

et al. 2018

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“…Moreover, we currently do not know if DPOR is active in the high-oxygen natural habitat of ICE-MDV and whether this alga has retained the ability to synthesize chlorophyll in the absence of light. Whatever the reasons for the presence of DPOR in ICE-MDV and its absence in UWO241, these data further emphasize just how unique UWO241 is relative to other green algae [7], both inside and outside of Lake Bonney.…”

Section: Main Documentmentioning

confidence: 73%

“…Among the best-studied algae that brave the lake's waters are Chlamydomonas sp. UWO241 [6,7] and Chlamydomonas sp. ICE-MDV [5,8].…”

Section: Main Documentmentioning

confidence: 99%

Presence and absence of light-independent chlorophyll biosynthesis among Chlamydomonas green algae in an ice-covered Antarctic lake

Smith

Cvetkovska

Hüner

et al. 2019

Communicative & Integrative Biology

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The cold, permanently ice-covered waters of Lake Bonney, Antarctica, may seem like an uninviting place for an alga, but they are home to a diversity of photosynthetic life, including Chlamydomonas sp. UWO241, a psychrophile residing in the deep photic zone. Recently, we found that UWO241 has lost the genes responsible for light-independent chlorophyll biosynthesis, which is surprising given that this green alga comes from a light-limited environment and experiences extended periods of darkness during the Antarctic winter. Why discard such a process? We argued that it might be linked to the very high dissolved oxygen concentration of Lake Bonney at the depth at which UWO241 is found. Oxygen is the Achilles' heel of the key enzyme involved in light-independent chlorophyll biosynthesis: DPOR. If this hypothesis is true, then other algae in Lake Bonney should also be susceptible to losing DPOR, such as Chlamydomonas sp. ICE-MDV, which predominantly resides in the chemocline, a depth with an even higher oxygen concentration than that where UWO241 exists. Here, we report that, contrary to our earlier prediction, ICE-MDV has maintained the genes encoding DPOR. We briefly discuss the implications of this finding in relation to the loss of light-independent chlorophyll synthesis in UWO241. ARTICLE HISTORY

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“…Change in the ice or snow algae composition can be attributed to variety of factors such as air temperature, altitude, distance from the ice margin, nutrient availability and source material (Mueller, Pollard 2004;Stibal et al 2010;Yallop et al 2012;Lutz et al 2014;Cvetkovska et al 2017;Anderson et al 2017). Although we have not tested the air temperature connection, overall air temperature increase most probably could be a forcing base in subsequent algae and environmental change (Tingley, Huybers 2013;Lutz et al 2014), and increase in GrIS melting (Tedesco et al 2016b).…”

Section: Discussionmentioning

confidence: 96%

Spheroidal carbonaceous particles in cryoconite sediment on the Russell glacier, Southwest Greenland

Stivriņš¹,

Lamsters²,

Karušs³

et al. 2019

Baltica

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In this study, we analysed the organic and inorganic content of the cryoconite holes along the altitudinal gradient at the lower elevations of the Russell glacier ablation zone in Southwest Greenland. We specifically focus on less studied industrial microscopic spheroidal carbonaceous particles (SCP; part of black carbon) to get more insights about their accumulation patterns on the glacier surface. We found no clear SCP distribution pattern, including concentration values. This outcome underlines the complexity of the ice margin zone and draws attention for further research on this topic with the inclusion of multiyear evaluation of SCP concentration at the even wider area that could possibly give results that can be compared to the emission source and long-way air pollution validation. In addition, our results indicate that during the summer of 2016, algae composition was formed of both green algae (Chlamydomonadaceae, Mesotaeniaceae) and cyanobacteria (Oscillatoriaceae). Green algae had a larger relative proportion than cyanobacteria in the cryoconite holes throughout the studied gradient.

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Chilling out: the evolution and diversification of psychrophilic algae with a focus on Chlamydomonadales

Cited by 51 publications

References 121 publications

Characterization of photosynthetic ferredoxin from the Antarctic alga Chlamydomonas sp. UWO241 reveals novel features of cold adaptation

Characterization of photosynthetic ferredoxin from the Antarctic alga Chlamydomonas sp. UWO241 reveals novel features of cold adaptation

Presence and absence of light-independent chlorophyll biosynthesis among Chlamydomonas green algae in an ice-covered Antarctic lake

Spheroidal carbonaceous particles in cryoconite sediment on the Russell glacier, Southwest Greenland

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