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Lopes JC, Kinasz CT, Luiz AMC, Kreusch MG, Duarte RTD. Frost fighters: unveiling the potential of microbial antifreeze proteins in biotech innovation. J Appl Microbiol 2024; 135:lxae140. [PMID: 38877650 DOI: 10.1093/jambio/lxae140] [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: 04/02/2024] [Revised: 05/30/2024] [Accepted: 06/13/2024] [Indexed: 06/16/2024]
Abstract
Polar environments pose extreme challenges for life due to low temperatures, limited water, high radiation, and frozen landscapes. Despite these harsh conditions, numerous macro and microorganisms have developed adaptive strategies to reduce the detrimental effects of extreme cold. A primary survival tactic involves avoiding or tolerating intra and extracellular freezing. Many organisms achieve this by maintaining a supercooled state by producing small organic compounds like sugars, glycerol, and amino acids, or through increasing solute concentration. Another approach is the synthesis of ice-binding proteins, specifically antifreeze proteins (AFPs), which hinder ice crystal growth below the melting point. This adaptation is crucial for preventing intracellular ice formation, which could be lethal, and ensuring the presence of liquid water around cells. AFPs have independently evolved in different species, exhibiting distinct thermal hysteresis and ice structuring properties. Beyond their ecological role, AFPs have garnered significant attention in biotechnology for potential applications in the food, agriculture, and pharmaceutical industries. This review aims to offer a thorough insight into the activity and impacts of AFPs on water, examining their significance in cold-adapted organisms, and exploring the diversity of microbial AFPs. Using a meta-analysis from cultivation-based and cultivation-independent data, we evaluate the correlation between AFP-producing microorganisms and cold environments. We also explore small and large-scale biotechnological applications of AFPs, providing a perspective for future research.
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Affiliation(s)
- Joana Camila Lopes
- Laboratory of Molecular Ecology and Extremophiles, Department of Microbiology, Immunology and Parasitology, Federal University of Santa Catarina-Campus Reitor João David Ferreira Lima, s/n Trindade, Florianópolis, SC 88040-900, Brazil
- Postgraduate Program in Biotechnology and Biosciences, Federal University of Santa Catarina, Campus Reitor João David Ferreira Lima, s/n Trindade, Florianópolis, SC 88040-900, Brazil
| | - Camila Tomazini Kinasz
- Laboratory of Molecular Ecology and Extremophiles, Department of Microbiology, Immunology and Parasitology, Federal University of Santa Catarina-Campus Reitor João David Ferreira Lima, s/n Trindade, Florianópolis, SC 88040-900, Brazil
- Postgraduate Program in Biotechnology and Biosciences, Federal University of Santa Catarina, Campus Reitor João David Ferreira Lima,, s/n Trindade, Florianópolis, SC 88040-900, Brazil
| | - Alanna Maylle Cararo Luiz
- Laboratory of Molecular Ecology and Extremophiles, Department of Microbiology, Immunology and Parasitology, Federal University of Santa Catarina-Campus Reitor João David Ferreira Lima, s/n Trindade, Florianópolis, SC 88040-900, Brazil
- Postgraduate Program in Biotechnology and Biosciences, Federal University of Santa Catarina, Campus Reitor João David Ferreira Lima,, s/n Trindade, Florianópolis, SC 88040-900, Brazil
| | - Marianne Gabi Kreusch
- Laboratory of Molecular Ecology and Extremophiles, Department of Microbiology, Immunology and Parasitology, Federal University of Santa Catarina-Campus Reitor João David Ferreira Lima, s/n Trindade, Florianópolis, SC 88040-900, Brazil
| | - Rubens Tadeu Delgado Duarte
- Laboratory of Molecular Ecology and Extremophiles, Department of Microbiology, Immunology and Parasitology, Federal University of Santa Catarina-Campus Reitor João David Ferreira Lima, s/n Trindade, Florianópolis, SC 88040-900, Brazil
- Postgraduate Program in Biotechnology and Biosciences, Federal University of Santa Catarina, Campus Reitor João David Ferreira Lima,, s/n Trindade, Florianópolis, SC 88040-900, Brazil
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Poirier M, Osmers P, Wilkins K, Morgan-Kiss RM, Cvetkovska M. Aberrant light sensing and motility in the green alga Chlamydomonas priscuii from the ice-covered Antarctic Lake Bonney. PLANT SIGNALING & BEHAVIOR 2023; 18:2184588. [PMID: 38126947 PMCID: PMC10012900 DOI: 10.1080/15592324.2023.2184588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 02/20/2023] [Indexed: 12/23/2023]
Abstract
The Antarctic green alga Chlamydomonas priscuii is an obligate psychrophile and an emerging model for photosynthetic adaptation to extreme conditions. Endemic to the ice-covered Lake Bonney, this alga thrives at highly unusual light conditions characterized by very low light irradiance (<15 μmol m-2 s-1), a narrow wavelength spectrum enriched in blue light, and an extreme photoperiod. Genome sequencing of C. priscuii exposed an unusually large genome, with hundreds of highly similar gene duplicates and expanded gene families, some of which could be aiding its survival in extreme conditions. In contrast to the described expansion in the genetic repertoire in C. priscuii, here we suggest that the gene family encoding for photoreceptors is reduced when compared to related green algae. This alga also possesses a very small eyespot and exhibits an aberrant phototactic response, compared to the model Chlamydomonas reinhardtii. We also investigated the genome and behavior of the closely related psychrophilic alga Chlamydomonas sp. ICE-MDV, that is found throughout the photic zone of Lake Bonney and is naturally exposed to higher light levels. Our analyses revealed a photoreceptor gene family and a robust phototactic response similar to those in the model Chlamydomonas reinhardtii. These results suggest that the aberrant phototactic response in C. priscuii is a result of life under extreme shading rather than a common feature of all psychrophilic algae. We discuss the implications of these results on the evolution and survival of shade adapted polar algae.
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Affiliation(s)
| | - Pomona Osmers
- Department of Biology, University of Ottawa, Ottawa, OH, Canada
| | - Kieran Wilkins
- Department of Biology, University of Ottawa, Ottawa, OH, Canada
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Stahl-Rommel S, Kalra I, D'Silva S, Hahn MM, Popson D, Cvetkovska M, Morgan-Kiss RM. Cyclic electron flow (CEF) and ascorbate pathway activity provide constitutive photoprotection for the photopsychrophile, Chlamydomonas sp. UWO 241 (renamed Chlamydomonas priscuii). PHOTOSYNTHESIS RESEARCH 2022; 151:235-250. [PMID: 34609708 DOI: 10.1007/s11120-021-00877-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Accepted: 09/13/2021] [Indexed: 06/13/2023]
Abstract
Under environmental stress, plants and algae employ a variety of strategies to protect the photosynthetic apparatus and maintain photostasis. To date, most studies on stress acclimation have focused on model organisms which possess limited to no tolerance to stressful extremes. We studied the ability of the Antarctic alga Chlamydomonas sp. UWO 241 (UWO 241) to acclimate to low temperature, high salinity or high light. UWO 241 maintained robust growth and photosynthetic activity at levels of temperature (2 °C) and salinity (700 mM NaCl) which were nonpermissive for a mesophilic sister species, Chlamydomonas raudensis SAG 49.72 (SAG 49.72). Acclimation in the mesophile involved classic mechanisms, including downregulation of light harvesting and shifts in excitation energy between photosystem I and II. In contrast, UWO 241 exhibited high rates of PSI-driven cyclic electron flow (CEF) and a larger capacity for nonphotochemical quenching (NPQ). Furthermore, UWO 241 exhibited constitutively high activity of two key ascorbate cycle enzymes, ascorbate peroxidase and glutathione reductase and maintained a large ascorbate pool. These results matched the ability of the psychrophile to maintain low ROS under short-term photoinhibition conditions. We conclude that tight control over photostasis and ROS levels are essential for photosynthetic life to flourish in a native habitat of permanent photooxidative stress. We propose to rename this organism Chlamydomonas priscuii.
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Affiliation(s)
- Sarah Stahl-Rommel
- Department of Microbiology, Miami University, Oxford, OH, 45045, USA
- JES Tech, Houston, TX, 77058, USA
| | - Isha Kalra
- Department of Microbiology, Miami University, Oxford, OH, 45045, USA
| | - Susanna D'Silva
- Department of Microbiology, Miami University, Oxford, OH, 45045, USA
| | - Mark M Hahn
- Department of Microbiology, Miami University, Oxford, OH, 45045, USA
| | - Devon Popson
- Department of Microbiology, Miami University, Oxford, OH, 45045, USA
| | - Marina Cvetkovska
- Department of Biology, University of Ottawa, Ottawa, ON, K1N 6N5, Canada
| | - Rachael M Morgan-Kiss
- Department of Microbiology, Miami University, Oxford, OH, 45045, USA.
- Department of Microbiology, Miami University, 700 E High St., 212 Pearson Hall, Oxford, OH, 45056, USA.
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4
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Zhang X, Cvetkovska M, Morgan-Kiss R, Hüner NPA, Smith DR. Draft genome sequence of the Antarctic green alga Chlamydomonas sp. UWO241. iScience 2021; 24:102084. [PMID: 33644715 PMCID: PMC7887394 DOI: 10.1016/j.isci.2021.102084] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/08/2020] [Accepted: 01/14/2021] [Indexed: 11/22/2022] Open
Abstract
Antarctica is home to an assortment of psychrophilic algae, which have evolved various survival strategies for coping with their frigid environments. Here, we explore Antarctic psychrophily by examining the ∼212 Mb draft nuclear genome of the green alga Chlamydomonas sp. UWO241, which resides within the water column of a perennially ice-covered, hypersaline lake. Like certain other Antarctic algae, UWO241 encodes a large number (≥37) of ice-binding proteins, putatively originating from horizontal gene transfer. Even more striking, UWO241 harbors hundreds of highly similar duplicated genes involved in diverse cellular processes, some of which we argue are aiding its survival in the Antarctic via gene dosage. Gene and partial gene duplication appear to be an ongoing phenomenon within UWO241, one which might be mediated by retrotransposons. Ultimately, we consider how such a process could be associated with adaptation to extreme environments but explore potential non-adaptive hypotheses as well. Chlamydomonas sp. UWO241 is a green alga originating from Lake Bonney, Antarctica We present a draft nuclear genome sequence of UWO241 (∼212 Mb). The UWO genome contains hundreds of highly similar duplicated genes These duplicates, we argue, might be involved in cold adaptation
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Affiliation(s)
- Xi Zhang
- Department of Biology, University of Western Ontario, London, ON N6A 5B7, Canada
| | - Marina Cvetkovska
- Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | | | - Norman P A Hüner
- Department of Biology, University of Western Ontario, London, ON N6A 5B7, Canada
| | - David Roy Smith
- Department of Biology, University of Western Ontario, London, ON N6A 5B7, Canada
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Hejduková E, Elster J, Nedbalová L. Annual Cycle of Freshwater Diatoms in the High Arctic Revealed by Multiparameter Fluorescent Staining. MICROBIAL ECOLOGY 2020; 80:559-572. [PMID: 32488483 DOI: 10.1007/s00248-020-01521-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 05/01/2020] [Indexed: 06/11/2023]
Abstract
Diatoms (Bacillariophyceae) are important primary producers in a wide range of hydro-terrestrial habitats in polar regions that are characterized by many extreme environmental conditions. Nevertheless, how they survive periods of drought and/or freeze remains unknown. A general strategy of microorganisms to overcome adverse conditions is dormancy, but morphologically distinct diatom resting stages are rare. This study aimed to evaluate the annual cycle of freshwater diatoms in the High Arctic (Central Spitsbergen) and provide an insight into their physiological cell status variability. The diversity and viability of diatom cells were studied in samples collected five times at four study sites, tracing the key events for survival (summer vegetative season, autumn dry-freezing, winter freezing, spring melting, summer vegetative season [again]). For viability evaluation, a multiparameter fluorescent staining was used in combination with light microscopy and allowed to reveal the physiological status at a single-cell level. The proportions of the cell categories were seasonally and locality dependent. The results suggested that a significant portion of vegetative cells survive winter and provide an inoculum for the following vegetative season. The ice thickness significantly influenced spring survival. The thicker the ice layer was, the more dead cells and fewer other stages were observed. The influence of the average week max-min temperature differences in autumn and winter was not proven.
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Affiliation(s)
- Eva Hejduková
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic.
| | - Josef Elster
- Institute of Botany of the Czech Academy of Sciences, Dukelská 135, 379 82, Třeboň, Czech Republic
- Centre for Polar Ecology, Faculty of Science, University of South Bohemia, Na Zlaté stoce 3, 370 05, České Budějovice, Czech Republic
| | - Linda Nedbalová
- Department of Ecology, Faculty of Science, Charles University, Viničná 7, 128 44, Prague 2, Czech Republic
- Institute of Botany of the Czech Academy of Sciences, Dukelská 135, 379 82, Třeboň, Czech Republic
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Raymond JA, Morgan-Kiss R, Stahl-Rommel S. Glycerol Is an Osmoprotectant in Two Antarctic Chlamydomonas Species From an Ice-Covered Saline Lake and Is Synthesized by an Unusual Bidomain Enzyme. FRONTIERS IN PLANT SCIENCE 2020; 11:1259. [PMID: 32973829 PMCID: PMC7468427 DOI: 10.3389/fpls.2020.01259] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 07/30/2020] [Indexed: 06/11/2023]
Abstract
Glycerol, a compatible solute, has previously been found to act as an osmoprotectant in some marine Chlamydomonas species and several species of Dunaliella from hypersaline ponds. Recently, Chlamydomonas reinhardtii and Dunaliella salina were shown to make glycerol with an unusual bidomain enzyme, which appears to be unique to algae, that contains a phosphoserine phosphatase and glycerol-3-phosphate dehydrogenase. Here we report that two psychrophilic species of Chlamydomonas (C. spp. UWO241 and ICE-MDV) from Lake Bonney, Antarctica also produce high levels of glycerol to survive in the lake's saline waters. Glycerol concentration increased linearly with salinity and at 1.3 M NaCl, exceeded 400 mM in C. sp. UWO241, the more salt-tolerant strain. We also show that both species expressed several isoforms of the bidomain enzyme. An analysis of one of the isoforms of C. sp. UWO241 showed that it was strongly upregulated by NaCl and is thus the likely source of glycerol. These results reveal another adaptation of the Lake Bonney Chlamydomonas species that allow them to survive in an extreme polar environment.
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Affiliation(s)
- James A. Raymond
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, United States
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Vallesi A, Pucciarelli S, Buonanno F, Fontana A, Mangiagalli M. Bioactive molecules from protists: Perspectives in biotechnology. Eur J Protistol 2020; 75:125720. [PMID: 32569992 DOI: 10.1016/j.ejop.2020.125720] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 05/11/2020] [Accepted: 05/15/2020] [Indexed: 12/14/2022]
Abstract
For hundreds of years, mankind has benefited from the natural metabolic processes of microorganisms to obtain basic products such as fermented foods and alcoholic beverages. More recently, microorganisms have been exploited for the production of antibiotics, vitamins and enzymes to be used in medicine and chemical industries. Additionally, several modern drugs, including those for cancer therapy, are natural products or their derivatives. Protists are a still underexplored source of natural products potentially of interest for biotechnological and biomedical applications. This paper focuses on some examples of bioactive molecules from protists and associated bacteria and their possible use in biotechnology.
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Affiliation(s)
- Adriana Vallesi
- School of Biosciences and Veterinary Medicine, Università degli Studi di Camerino, Camerino (MC), Italy.
| | - Sandra Pucciarelli
- School of Biosciences and Veterinary Medicine, Università degli Studi di Camerino, Camerino (MC), Italy.
| | - Federico Buonanno
- Laboratory of Protistology and Biology Education, Department of E.C.H.T. Università degli Studi di Macerata, Macerata, Italy
| | - Angelo Fontana
- Bio-Organic Chemistry Unit, CNR-Institute of Biomolecular Chemistry, Pozzuoli, Napoli, Italy
| | - Marco Mangiagalli
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milano, Italy
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Cho SM, Kim S, Cho H, Lee H, Lee JH, Lee H, Park H, Kang S, Choi HG, Lee J. Type II Ice-Binding Proteins Isolated from an Arctic Microalga Are Similar to Adhesin-Like Proteins and Increase Freezing Tolerance in Transgenic Plants. PLANT & CELL PHYSIOLOGY 2019; 60:2744-2757. [PMID: 31418793 DOI: 10.1093/pcp/pcz162] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 08/11/2019] [Indexed: 06/10/2023]
Abstract
Microalgal ice-binding proteins (IBPs) in the polar region are poorly understood at the genome-wide level, although they are important for cold adaptation. Through the transcriptome study with the Arctic green alga Chloromonas sp. KNF0032, we identified six Chloromonas IBP genes (CmIBPs), homologous with the previously reported IBPs from Antarctic snow alga CCMP681 and Antarctic Chloromonas sp. They were organized with multiple exon/intron structures and low-temperature-responsive cis-elements in their promoters and abundantly expressed at low temperature. The biological functions of three representative CmIBPs (CmIBP1, CmIBP2 and CmIBP3) were tested using in vitro analysis and transgenic plant system. CmIBP1 had the most effective ice recrystallization inhibition (IRI) activities in both in vitro and transgenic plants, and CmIBP2 and CmIBP3 had followed. All transgenic plants grown under nonacclimated condition were freezing tolerant, and especially 35S::CmIBP1 plants were most effective. After cold acclimation, only 35S::CmIBP2 plants showed slightly increased freezing tolerance. Structurally, the CmIBPs were predicted to have β-solenoid forms with parallel β-sheets and repeated TXT motifs. The repeated TXT structure of CmIBPs appears similar to the AidA domain-containing adhesin-like proteins from methanogens. We have shown that the AidA domain has IRI activity as CmIBPs and phylogenetic analysis also supported that the AidA domains are monophyletic with ice-binding domain of CmIBPs, and these results suggest that CmIBPs are a type of modified adhesins.
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Affiliation(s)
- Sung Mi Cho
- Unit of Polar Genomics, Korea Polar Research Institute (KOPRI), Yeonsu-gu, Incheon 21990, Republic of Korea
| | - Sanghee Kim
- Division of Polar Life Sciences, Korea Polar Research Institute (KOPRI), Yeonsu-gu, Incheon 21990, Republic of Korea
| | - Hojin Cho
- Unit of Polar Genomics, Korea Polar Research Institute (KOPRI), Yeonsu-gu, Incheon 21990, Republic of Korea
- Department of Polar Science, University of Science and Technology, Daejeon 34113, Republic of Korea
| | - Hyoungseok Lee
- Unit of Polar Genomics, Korea Polar Research Institute (KOPRI), Yeonsu-gu, Incheon 21990, Republic of Korea
- Department of Polar Science, University of Science and Technology, Daejeon 34113, Republic of Korea
| | - Jun Hyuck Lee
- Unit of Polar Genomics, Korea Polar Research Institute (KOPRI), Yeonsu-gu, Incheon 21990, Republic of Korea
- Department of Polar Science, University of Science and Technology, Daejeon 34113, Republic of Korea
| | - Horim Lee
- Department of Biotechnology, Duksung Women's University, Seoul 01369, Republic of Korea
| | - Hyun Park
- Unit of Polar Genomics, Korea Polar Research Institute (KOPRI), Yeonsu-gu, Incheon 21990, Republic of Korea
- Department of Polar Science, University of Science and Technology, Daejeon 34113, Republic of Korea
- Division of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Seunghyun Kang
- Unit of Polar Genomics, Korea Polar Research Institute (KOPRI), Yeonsu-gu, Incheon 21990, Republic of Korea
| | - Han-Gu Choi
- Division of Polar Life Sciences, Korea Polar Research Institute (KOPRI), Yeonsu-gu, Incheon 21990, Republic of Korea
| | - Jungeun Lee
- Unit of Polar Genomics, Korea Polar Research Institute (KOPRI), Yeonsu-gu, Incheon 21990, Republic of Korea
- Department of Polar Science, University of Science and Technology, Daejeon 34113, Republic of Korea
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Raymond JA, Remias D. Ice-Binding Proteins in a Chrysophycean Snow Alga: Acquisition of an Essential Gene by Horizontal Gene Transfer. Front Microbiol 2019; 10:2697. [PMID: 31849866 PMCID: PMC6892780 DOI: 10.3389/fmicb.2019.02697] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 11/06/2019] [Indexed: 01/08/2023] Open
Abstract
All ice-associated algae examined so far have genes for ice-binding proteins (IBPs), which suggest that these proteins are essential for survival in icy habitats. The most common type of IBP, type 1 IBPs (also referred to as DUF3494 IBPs), is also found in ice-associated bacteria and fungi. Previous studies have suggested that algal IBP genes were acquired by horizontal transfer from other microorganisms (probably bacteria). However, it remains unclear whether this is also the case for algae distantly related to the ones examined so far and whether microorganisms other than bacteria could be the donors. Furthermore, there is only limited evidence that these proteins are expressed at low temperature. Here, we show that Kremastochrysopsis austriaca (Chrysophyceae), an Austrian snow alga that is not closely related to any of the ice-associated algae examined so far, also produces IBPs, although their activity was weak. Sequencing the algal genome and the transcriptomes of cells grown at 1 and 15°C revealed three isoforms of a type 1 IBP. In agreement with their putative function, the three isoforms were strongly upregulated by one to two orders of magnitude at 1°C compared to 15°C. In a phylogenetic tree, the K. austriaca IBPs were distant from other algal IBPs, with the closest matches being bacterial proteins. These results suggest that the K. austriaca IBPs were derived from a gene that was acquired from a bacterium unrelated to other IBP donor bacteria and confirm by their presence in yet another alga the essential role of algal IBPs.
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Affiliation(s)
- James A Raymond
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV, United States
| | - Daniel Remias
- School of Engineering, University of Applied Sciences Upper Austria, Wels, Austria
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Cook G, Teufel A, Kalra I, Li W, Wang X, Priscu J, Morgan-Kiss R. The Antarctic psychrophiles Chlamydomonas spp. UWO241 and ICE-MDV exhibit differential restructuring of photosystem I in response to iron. PHOTOSYNTHESIS RESEARCH 2019; 141:209-228. [PMID: 30729447 DOI: 10.1007/s11120-019-00621-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 01/25/2019] [Indexed: 06/09/2023]
Abstract
Chlamydomonas sp. UWO241 is a psychrophilic alga isolated from the deep photic zone of a perennially ice-covered Antarctic lake (east lobe Lake Bonney, ELB). Past studies have shown that C. sp. UWO241 exhibits constitutive downregulation of photosystem I (PSI) and high rates of PSI-associated cyclic electron flow (CEF). Iron levels in ELB are in the nanomolar range leading us to hypothesize that the unusual PSI phenotype of C. sp. UWO241 could be a response to chronic Fe-deficiency. We studied the impact of Fe availability in C. sp. UWO241, a mesophile, C. reinhardtii SAG11-32c, as well as a psychrophile isolated from the shallow photic zone of ELB, Chlamydomonas sp. ICE-MDV. Under Fe-deficiency, PsaA abundance and levels of photooxidizable P700 (ΔA820/A820) were reduced in both psychrophiles relative to the mesophile. Upon increasing Fe, C. sp. ICE-MDV and C. reinhardtii exhibited restoration of PSI function, while C. sp. UWO241 exhibited only moderate changes in PSI activity and lacked almost all LHCI proteins. Relative to Fe-excess conditions (200 µM Fe2+), C. sp. UWO241 grown in 18 µM Fe2+ exhibited downregulation of light harvesting and photosystem core proteins, as well as upregulation of a bestrophin-like anion channel protein and two CEF-associated proteins (NdsS, PGL1). Key enzymes of starch synthesis and shikimate biosynthesis were also upregulated. We conclude that in response to variable Fe availability, the psychrophile C. sp. UWO241 exhibits physiological plasticity which includes restructuring of the photochemical apparatus, increased PSI-associated CEF, and shifts in downstream carbon metabolism toward storage carbon and secondary stress metabolites.
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Affiliation(s)
- Greg Cook
- Department of Microbiology, Miami University, 700 E High St., 32 Pearson Hall, Oxford, OH, 45056, USA
| | - Amber Teufel
- Department of Microbiology, Miami University, 700 E High St., 32 Pearson Hall, Oxford, OH, 45056, USA
| | - Isha Kalra
- Department of Microbiology, Miami University, 700 E High St., 32 Pearson Hall, Oxford, OH, 45056, USA
| | - Wei Li
- Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, USA
| | - Xin Wang
- Department of Microbiology, Miami University, 700 E High St., 32 Pearson Hall, Oxford, OH, 45056, USA
| | - John Priscu
- Land Resources and Environmental Sciences, Montana State University, Bozeman, MT, USA
| | - Rachael Morgan-Kiss
- Department of Microbiology, Miami University, 700 E High St., 32 Pearson Hall, Oxford, OH, 45056, USA.
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11
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Arai T, Fukami D, Hoshino T, Kondo H, Tsuda S. Ice-binding proteins from the fungus Antarctomyces psychrotrophicus possibly originate from two different bacteria through horizontal gene transfer. FEBS J 2018; 286:946-962. [PMID: 30548092 DOI: 10.1111/febs.14725] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 11/03/2018] [Accepted: 12/06/2018] [Indexed: 12/12/2022]
Abstract
Various microbes, including fungi and bacteria, that live in cold environments produce ice-binding proteins (IBPs) that protect them from freezing. Ascomycota and Basidiomycota are two major phyla of fungi, and Antarctomyces psychrotrophicus is currently designated as the sole ascomycete that produces IBP (AnpIBP). However, its complete amino acid sequence, ice-binding property, and evolutionary history have not yet been clarified. Here, we determined the peptide sequences of three new AnpIBP isoforms by total cDNA analysis and compared them with those of other microbial IBPs. The AnpIBP isoforms and ascomycete-putative IBPs were found to be phylogenetically close to the bacterial ones but far from the basidiomycete ones, which is supported by the higher sequence identities to bacterial IBPs than basidiomycete IBPs, although ascomycetes are phylogenetically distant from bacteria. In addition, two of the isoforms of AnpIBP share low sequence identity and are not close in the phylogenetic tree. It is hence presumable that these two AnpIBP isoforms were independently acquired from different bacteria through horizontal gene transfer (HGT), which implies that ascomycetes and bacteria frequently exchange their IBP genes. The non-colligative freezing-point depression ability of AnpIBP was not very high, whereas it exhibited significant abilities of ice recrystallization inhibition, ice shaping, and cryo-protection against freeze-thaw cycles even at submicromolar concentrations. These results suggest that HGT is crucial for the cold-adaptive evolution of ascomycetes, and their IBPs offer freeze resistance to organisms to enable them to inhabit the icy environments of Antarctica. DATABASES: Nucleotide sequence data are available in the DDBJ database under the accession numbers LC378707, LC378707, LC378707 for AnpIBP1a, AnpIBP1b, AnpIBP2, respectively.
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Affiliation(s)
- Tatsuya Arai
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Daichi Fukami
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Tamotsu Hoshino
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, Japan
| | - Hidemasa Kondo
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan.,Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, Japan
| | - Sakae Tsuda
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan.,Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo, Japan.,OPERANDO Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
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12
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Raymond JA, Morgan-Kiss R. Multiple ice-binding proteins of probable prokaryotic origin in an Antarctic lake alga, Chlamydomonas sp. ICE-MDV (Chlorophyceae). JOURNAL OF PHYCOLOGY 2017; 53:848-854. [PMID: 28543018 PMCID: PMC5546997 DOI: 10.1111/jpy.12550] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 03/27/2017] [Indexed: 05/14/2023]
Abstract
Ice-associated algae produce ice-binding proteins (IBPs) to prevent freezing damage. The IBPs of the three chlorophytes that have been examined so far share little similarity across species, making it likely that they were acquired by horizontal gene transfer (HGT). To clarify the importance and source of IBPs in chlorophytes, we sequenced the IBP genes of another Antarctic chlorophyte, Chlamydomonas sp. ICE-MDV (Chlamy-ICE). Genomic DNA and total RNA were sequenced and screened for known ice-associated genes. Chlamy-ICE has as many as 50 IBP isoforms, indicating that they have an important role in survival. The IBPs are of the DUF3494 type and have similar exon structures. The DUF3494 sequences are much more closely related to prokaryotic sequences than they are to sequences in other chlorophytes, and the chlorophyte IBP and ribosomal 18S phylogenies are dissimilar. The multiple IBP isoforms found in Chlamy-ICE and other algae may allow the algae to adapt to a greater variety of ice conditions than prokaryotes, which typically have a single IBP gene. The predicted structure of the DUF3494 domain has an ice-binding face with an orderly array of hydrophilic side chains. The results indicate that Chlamy-ICE acquired its IBP genes by HGT in a single event. The acquisitions of IBP genes by this and other species of Antarctic algae by HGT appear to be key evolutionary events that allowed algae to extend their ranges into polar environments.
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Affiliation(s)
- James A. Raymond
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, Nevada 89154 USA
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13
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Chilling out: the evolution and diversification of psychrophilic algae with a focus on Chlamydomonadales. Polar Biol 2016. [DOI: 10.1007/s00300-016-2045-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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14
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Jung W, Campbell RL, Gwak Y, Kim JI, Davies PL, Jin E. New Cysteine-Rich Ice-Binding Protein Secreted from Antarctic Microalga, Chloromonas sp. PLoS One 2016; 11:e0154056. [PMID: 27097164 PMCID: PMC4838330 DOI: 10.1371/journal.pone.0154056] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 04/07/2016] [Indexed: 11/18/2022] Open
Abstract
Many microorganisms in Antarctica survive in the cold environment there by producing ice-binding proteins (IBPs) to control the growth of ice around them. An IBP from the Antarctic freshwater microalga, Chloromonas sp., was identified and characterized. The length of the Chloromonas sp. IBP (ChloroIBP) gene was 3.2 kb with 12 exons, and the molecular weight of the protein deduced from the ChloroIBP cDNA was 34.0 kDa. Expression of the ChloroIBP gene was up- and down-regulated by freezing and warming conditions, respectively. Western blot analysis revealed that native ChloroIBP was secreted into the culture medium. This protein has fifteen cysteines and is extensively disulfide bonded as shown by in-gel mobility shifts between oxidizing and reducing conditions. The open-reading frame of ChloroIBP was cloned and over-expressed in Escherichia coli to investigate the IBP’s biochemical characteristics. Recombinant ChloroIBP produced as a fusion protein with thioredoxin was purified by affinity chromatography and formed single ice crystals of a dendritic shape with a thermal hysteresis activity of 0.4±0.02°C at a concentration of 5 mg/ml. In silico structural modeling indicated that the three-dimensional structure of ChloroIBP was that of a right-handed β-helix. Site-directed mutagenesis of ChloroIBP showed that a conserved region of six parallel T-X-T motifs on the β-2 face was the ice-binding region, as predicted from the model. In addition to disulfide bonding, hydrophobic interactions between inward-pointing residues on the β-1 and β-2 faces, in the region of ice-binding motifs, were crucial to maintaining the structural conformation of ice-binding site and the ice-binding activity of ChloroIBP.
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Affiliation(s)
- Woongsic Jung
- Department of Life Science, Hanyang University, Seoul, South Korea
| | - Robert L. Campbell
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Canada K7L-3N6
| | - Yunho Gwak
- Department of Life Science, Hanyang University, Seoul, South Korea
| | - Jong Im Kim
- Department of Biology, Chungnam National University, Daejeon, South Korea
| | - Peter L. Davies
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Canada K7L-3N6
- * E-mail: (PLD); (EJ)
| | - EonSeon Jin
- Department of Life Science, Hanyang University, Seoul, South Korea
- * E-mail: (PLD); (EJ)
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15
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Mock T, Daines SJ, Geider R, Collins S, Metodiev M, Millar AJ, Moulton V, Lenton TM. Bridging the gap between omics and earth system science to better understand how environmental change impacts marine microbes. GLOBAL CHANGE BIOLOGY 2016; 22:61-75. [PMID: 25988950 PMCID: PMC4949645 DOI: 10.1111/gcb.12983] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 05/05/2015] [Accepted: 05/12/2015] [Indexed: 05/17/2023]
Abstract
The advent of genomic-, transcriptomic- and proteomic-based approaches has revolutionized our ability to describe marine microbial communities, including biogeography, metabolic potential and diversity, mechanisms of adaptation, and phylogeny and evolutionary history. New interdisciplinary approaches are needed to move from this descriptive level to improved quantitative, process-level understanding of the roles of marine microbes in biogeochemical cycles and of the impact of environmental change on the marine microbial ecosystem. Linking studies at levels from the genome to the organism, to ecological strategies and organism and ecosystem response, requires new modelling approaches. Key to this will be a fundamental shift in modelling scale that represents micro-organisms from the level of their macromolecular components. This will enable contact with omics data sets and allow acclimation and adaptive response at the phenotype level (i.e. traits) to be simulated as a combination of fitness maximization and evolutionary constraints. This way forward will build on ecological approaches that identify key organism traits and systems biology approaches that integrate traditional physiological measurements with new insights from omics. It will rely on developing an improved understanding of ecophysiology to understand quantitatively environmental controls on microbial growth strategies. It will also incorporate results from experimental evolution studies in the representation of adaptation. The resulting ecosystem-level models can then evaluate our level of understanding of controls on ecosystem structure and function, highlight major gaps in understanding and help prioritize areas for future research programs. Ultimately, this grand synthesis should improve predictive capability of the ecosystem response to multiple environmental drivers.
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Affiliation(s)
- Thomas Mock
- School of Environmental SciencesUniversity of East AngliaNorwich Research ParkNR4 7TJNorwichUK
| | - Stuart J. Daines
- College of Life and Environmental SciencesUniversity of ExeterEX4 4QEExeterUK
| | - Richard Geider
- School of Biological SciencesUniversity of EssexWivenhoe ParkColchesterCO4 3SQUK
| | - Sinead Collins
- Ashworth LaboratoriesEdinburgh UniversityEH9 3JFEdinburghUK
| | - Metodi Metodiev
- School of Biological SciencesUniversity of EssexWivenhoe ParkColchesterCO4 3SQUK
| | - Andrew J. Millar
- SynthSys and School of Biological SciencesEdinburgh UniversityEH9 3BFEdinburghUK
| | - Vincent Moulton
- School of Computing SciencesUniversity of East AngliaNorwich Research ParkNR4 7TJNorwichUK
| | - Timothy M. Lenton
- College of Life and Environmental SciencesUniversity of ExeterEX4 4QEExeterUK
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In situ expression of eukaryotic ice-binding proteins in microbial communities of Arctic and Antarctic sea ice. ISME JOURNAL 2015; 9:2537-40. [PMID: 25885562 PMCID: PMC4611500 DOI: 10.1038/ismej.2015.43] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 02/17/2015] [Accepted: 02/26/2015] [Indexed: 11/29/2022]
Abstract
Ice-binding proteins (IBPs) have been isolated from various sea-ice organisms. Their characterisation points to a crucial role in protecting the organisms in sub-zero environments. However, their in situ abundance and diversity in natural sea-ice microbial communities is largely unknown. In this study, we analysed the expression and phylogenetic diversity of eukaryotic IBP transcripts from microbial communities of Arctic and Antarctic sea ice. IBP transcripts were found in abundances similar to those of proteins involved in core cellular processes such as photosynthesis. Eighty-nine percent of the IBP transcripts grouped with known IBP sequences from diatoms, haptophytes and crustaceans, but the majority represented novel sequences not previously characterized in cultured organisms. The observed high eukaryotic IBP expression in natural eukaryotic sea ice communities underlines the essential role of IBPs for survival of many microorganisms in communities living under the extreme conditions of polar sea ice.
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The ice-binding proteins of a snow alga, Chloromonas brevispina: probable acquisition by horizontal gene transfer. Extremophiles 2014; 18:987-94. [PMID: 25081506 DOI: 10.1007/s00792-014-0668-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 06/26/2014] [Indexed: 10/25/2022]
Abstract
All ice-and snow-related unicellular algae examined so far secrete ice-binding proteins (IBPs) to mitigate freezing damage. Two types of IBP have been identified in chlorophytes. Type 1 IBPs are members of a large family of proteins that share a large domain of unknown function (DUF3494). Previous studies have suggested that the type 1 algal IBP genes were acquired by horizontal gene transfer. To test this hypothesis I sequenced the IBP genes of a snow alga, Chloromonas brevispina. The IBPs were identified by ice affinity purification, de novo sequencing of a tryptic peptide and large-scale sequencing of the transcriptome and genome. C. brevispina has genes for over 20 IBP isoforms, which strongly indicates their importance. The IBPs are all of type 1 and match fungal and bacterial proteins more closely than they match known algal IBPs, providing further evidence that the genes were acquired by horizontal transfer. Modeling of the 3D structures of the IBPs based on the known structure of a homologous protein suggests that the ice-binding site has characteristics that are shared by all DUF3494 proteins.
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Lyon BR, Mock T. Polar Microalgae: New Approaches towards Understanding Adaptations to an Extreme and Changing Environment. BIOLOGY 2014; 3:56-80. [PMID: 24833335 PMCID: PMC4009763 DOI: 10.3390/biology3010056] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 01/22/2014] [Accepted: 01/24/2014] [Indexed: 02/02/2023]
Abstract
Polar Regions are unique and highly prolific ecosystems characterized by extreme environmental gradients. Photosynthetic autotrophs, the base of the food web, have had to adapt physiological mechanisms to maintain growth, reproduction and metabolic activity despite environmental conditions that would shut-down cellular processes in most organisms. High latitudes are characterized by temperatures below the freezing point, complete darkness in winter and continuous light and high UV in the summer. Additionally, sea-ice, an ecological niche exploited by microbes during the long winter seasons when the ocean and land freezes over, is characterized by large salinity fluctuations, limited gas exchange, and highly oxic conditions. The last decade has been an exciting period of insights into the molecular mechanisms behind adaptation of microalgae to the cryosphere facilitated by the advancement of new scientific tools, particularly "omics" techniques. We review recent insights derived from genomics, transcriptomics, and proteomics studies. Genes, proteins and pathways identified from these highly adaptable polar microbes have far-reaching biotechnological applications. Furthermore, they may provide insights into life outside this planet, as well as glimpses into the past. High latitude regions also have disproportionately large inputs into global biogeochemical cycles and are the region most sensitive to climate change.
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Affiliation(s)
- Barbara R Lyon
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK.
| | - Thomas Mock
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK.
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Singh P, Hanada Y, Singh SM, Tsuda S. Antifreeze protein activity in Arctic cryoconite bacteria. FEMS Microbiol Lett 2013; 351:14-22. [PMID: 24283367 DOI: 10.1111/1574-6968.12345] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 11/23/2013] [Accepted: 11/24/2013] [Indexed: 11/30/2022] Open
Abstract
Fourteen Arctic bacterial strains belonging to five genera, Cryobacterium, Leifsonia, Polaromonas, Pseudomonas, and Subtercola isolated from sediments found in cryoconite holes of Arctic glaciers, were subjected to screening for antifreeze proteins (AFPs). Eight strains showed AFP activity, and six strains of four species were further characterized. Pseudomonas ficuserectae exhibited a high thermal hysteresis (TH) activity. Ice recrystallization inhibition (IRI) activity was observed in most cultures at low protein concentration. Bacterial AFPs produced rounded shape of ice crystals that did not change their size and morphology within the TH window. Cry-g (P. ficuserectae) failed to inhibit ice recrystallization, indicating that the IRI activity of the AFPs does not relate to the strength of TH activity. SDS-PAGE analysis of the AFPs suggests their apparent molecular weights to be around 23 kDa. This study is significant as it screens several species of Arctic bacterial strains for AFP activity. So far, only one species of bacteria, Pseudomonas putida, was reported from the Arctic to produce AFPs. N-terminal amino acid sequence analysis shows that the bacterial AFPs isolated belong to the AFP family IBP-1, which is known to have an important physiological role in the cold environment. AFPs of glacier cryoconite habitat have been discussed.
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Affiliation(s)
- Purnima Singh
- Birla Institute of Technology and Science (BITS), Goa campus, Zuarinagar, Goa, India
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20
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Ice recrystallization inhibition mediated by a nuclear-expressed and -secreted recombinant ice-binding protein in the microalga Chlamydomonas reinhardtii. Appl Microbiol Biotechnol 2013; 97:9763-72. [PMID: 24037309 DOI: 10.1007/s00253-013-5226-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 08/26/2013] [Accepted: 08/28/2013] [Indexed: 01/08/2023]
Abstract
A Lolium perenne ice-binding protein (LpIBP) demonstrates superior ice recrystallization inhibition (IRI) activity and has proposed applications in cryopreservation, food texturing, as well as in being a "green" gas hydrate inhibitor. Recombinant production of LpIBP has been previously conducted in bacterial and yeast systems for studies of protein characterization, but large-scale applications have been hitherto limited due to high production costs. In this work, a codon-optimized LpIBP was recombinantly expressed and secreted in a novel one-step vector system from the nuclear genome of the green microalga Chlamydomonas reinhardtii. Both mixotrophic and photoautotrophic growth regimes supported LpIBP expression, indicating the feasibility of low-cost production using minimal medium, carbon dioxide, and light energy as input. In addition, multiple growth and bioproduct extraction cycles were performed by repetitive batch cultivation trials, demonstrating the potential for semi-continuous production and biomass harvesting. Concentrations of recombinant protein reached in this proof of concept approach were sufficient to demonstrate IRI activity in culture media without additional purification or concentration, with activity further verified by thermal hysteresis and morphology assays. The incorporation of the recombinant LpIBP into a model gas hydrate offers the promise that algal production may eventually find application as a "green" hydrate inhibitor.
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21
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Dolhi JM, Maxwell DP, Morgan-Kiss RM. The Antarctic Chlamydomonas raudensis: an emerging model for cold adaptation of photosynthesis. Extremophiles 2013; 17:711-22. [PMID: 23903324 DOI: 10.1007/s00792-013-0571-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 07/18/2013] [Indexed: 10/26/2022]
Abstract
Permanently cold habitats dominate our planet and psychrophilic microorganisms thrive in cold environments. Environmental adaptations unique to psychrophilic microorganisms have been thoroughly described; however, the vast majority of studies to date have focused on cold-adapted bacteria. The combination of low temperatures in the presence of light is one of the most damaging environmental stresses for a photosynthetic organism: in order to survive, photopsychrophiles (i.e. photosynthetic organisms adapted to low temperatures) balance temperature-independent reactions of light energy capture/transduction with downstream temperature-dependent metabolic processes such as carbon fixation. Here, we review research on photopsychrophiles with a focus on an emerging model organism, Chlamydomonas raudensis UWO241 (UWO241). UWO241 is a psychrophilic green algal species and is a member of the photosynthetic microbial eukaryote community that provides the majority of fixed carbon for ice-covered lake ecosystems located in the McMurdo Dry Valleys, Antarctica. The water column exerts a range of environmental stressors on the phytoplankton community that inhabits this aquatic ecosystem, including low temperatures, extreme shade of an unusual spectral range (blue-green), high salinity, nutrient deprivation and extremes in seasonal photoperiod. More than two decades of work on UWO241 have produced one of our most comprehensive views of environmental adaptation in a cold-adapted, photosynthetic microbial eukaryote.
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Affiliation(s)
- Jenna M Dolhi
- Department of Microbiology, Miami University, 700 E High St., 32 Pearson Hall, Oxford, OH 45056, USA
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