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Huang YP, Paviani B, Fukagawa NK, Phillips KM, Barile D. Comprehensive oligosaccharide profiling of commercial almond milk, soy milk, and soy flour. Food Chem 2023; 409:135267. [PMID: 36586264 DOI: 10.1016/j.foodchem.2022.135267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 12/16/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
Oligosaccharides are known for several bioactivities on health, however, in sensitive individuals, can cause intestinal discomfort. This study aimed to investigate the oligosaccharide profiles in selected plant-based food products. A quantification method based on high-performance anion-exchange chromatography-pulsed amperometric detection was developed, validated, and used to measure major oligosaccharides. Additional low-abundant oligosaccharides and glycosides were characterized by liquid chromatography-tandem mass spectrometry and glycosidases. The summed concentration of raffinose, stachyose, and verbascose ranged from 0.12-0.19 mg/g in almond milk, 3.6-6.4 mg/g in soy milk, and 74-77 and 4.8-57 mg/g in defatted and full-fat soy four. Over 80 different oligosaccharides were characterized. Novel compounds, 2,3-butanediol glycosides, were identified in almond milk. Low-abundant oligosaccharides represented 25 %, 6 %, and 10 % of total OS in almond milk, soy milk, and soy flour, respectively. The data here are useful to estimate oligosaccharide consumption from dietary intake and facilitate further studies on their bioactivity.
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Affiliation(s)
- Yu-Ping Huang
- Department of Food Science and Technology, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States
| | - Bruna Paviani
- Department of Food Science and Technology, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States
| | - Naomi K Fukagawa
- USDA ARS Beltsville Human Nutrition Research Center, 10300 Baltimore Ave, BARC-East, Center Road, Beltsville, MD 20705, United States
| | | | - Daniela Barile
- Department of Food Science and Technology, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States; Foods for Health Institute, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States.
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Zhu S, Gu D, Lu C, Zhang C, Chen J, Yang R, Luo Q, Wang T, Zhang P, Chen H. Cold stress tolerance of the intertidal red alga Neoporphyra haitanensis. BMC PLANT BIOLOGY 2022; 22:114. [PMID: 35287582 PMCID: PMC8919617 DOI: 10.1186/s12870-022-03507-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 02/28/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND Red algae Porphyra sensu lato grow naturally in the unfavorable intertidal environment, in which they are exposed to substantial temperature fluctuations. The strategies of Porphyra to tolerate cold stress are poorly understood. RESULTS Herein, investigations revealed that chilling and freezing induced alterations in the physiological properties, gene transcriptional profiles and metabolite levels in the economically important red algae species, Neoporphyra haitanensis. Control samples (kept at 20 °C) were compared to chilled thalli (10 and 4 °C) and to thalli under - 4 °C conditions. Chilling stress did not affect the health or photosynthetic efficiency of gametophytes, but freezing conditions resulted in the arrest of growth, death of some cells and a decrease in photosynthetic activity as calculated by Fv/Fm. Transcriptome sequencing analysis revealed that the photosynthetic system was down-regulated along with genes associated with carbon fixation and primary metabolic biosynthesis. Adaptive mechanisms included an increase in unsaturated fatty acids levels to improve membrane fluidity, an increase in floridoside and isofloridoside content to enhance osmotic resistance, and an elevation in levels of some resistance-associated phytohormones (abscisic acid, salicylic acid, and methyl jasmonic acid). These physiochemical alterations occurred together with the upregulation of ribosome biogenesis. CONCLUSIONS N. haitanensis adopts multiple protective mechanisms to maintain homeostasis of cellular physiology in tolerance to cold stress.
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Affiliation(s)
- Shanshan Zhu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, Zhejiang, China
- College of Life Sciences, Zhejiang University, Hangzhou, 310058, Zhejiang, China
| | - Denghui Gu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, Zhejiang, China
| | - Caiping Lu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, Zhejiang, China
| | - Caixia Zhang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, Zhejiang, China
| | - Juanjuan Chen
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, Zhejiang, China
- Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo University, Ningbo, 315211, Zhejiang, China
| | - Rui Yang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, Zhejiang, China
- Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo University, Ningbo, 315211, Zhejiang, China
| | - Qijun Luo
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, Zhejiang, China
- Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo University, Ningbo, 315211, Zhejiang, China
| | - Tiegan Wang
- Zhejiang Mariculture Research Institute, Wenzhou, 325005, China
| | - Peng Zhang
- Zhejiang Mariculture Research Institute, Wenzhou, 325005, China
| | - Haimin Chen
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, 315211, Zhejiang, China.
- Collaborative Innovation Center for Zhejiang Marine High-efficiency and Healthy Aquaculture, Ningbo University, Ningbo, 315211, Zhejiang, China.
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Yanshin N, Kushnareva A, Lemesheva V, Birkemeyer C, Tarakhovskaya E. Chemical Composition and Potential Practical Application of 15 Red Algal Species from the White Sea Coast (the Arctic Ocean). Molecules 2021; 26:2489. [PMID: 33923301 PMCID: PMC8123152 DOI: 10.3390/molecules26092489] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 04/21/2021] [Accepted: 04/21/2021] [Indexed: 02/03/2023] Open
Abstract
Though numerous valuable compounds from red algae already experience high demand in medicine, nutrition, and different branches of industry, these organisms are still recognized as an underexploited resource. This study provides a comprehensive characterization of the chemical composition of 15 Arctic red algal species from the perspective of their practical relevance in medicine and the food industry. We show that several virtually unstudied species may be regarded as promising sources of different valuable metabolites and minerals. Thus, several filamentous ceramialean algae (Ceramium virgatum, Polysiphonia stricta, Savoiea arctica) had total protein content of 20-32% of dry weight, which is comparable to or higher than that of already commercially exploited species (Palmaria palmata, Porphyra sp.). Moreover, ceramialean algae contained high amounts of pigments, macronutrients, and ascorbic acid. Euthora cristata (Gigartinales) accumulated free essential amino acids, taurine, pantothenic acid, and floridoside. Thalli of P. palmata and C. virgatum contained the highest amounts of the nonproteinogenic amino acid β-alanine (9.1 and 3.2 μM g-1 DW, respectively). Several red algae tend to accumulate heavy metals; although this may limit their application in the food industry, it makes them promising candidates for phytoremediation or the use as bioindicators.
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Affiliation(s)
- Nikolay Yanshin
- Department of Plant Physiology and Biochemistry, Faculty of Biology, St. Petersburg State University, 199034 St. Petersburg, Russia; (N.Y.); (V.L.)
| | | | - Valeriia Lemesheva
- Department of Plant Physiology and Biochemistry, Faculty of Biology, St. Petersburg State University, 199034 St. Petersburg, Russia; (N.Y.); (V.L.)
| | - Claudia Birkemeyer
- Faculty of Chemistry and Mineralogy, University of Leipzig, 04103 Leipzig, Germany;
| | - Elena Tarakhovskaya
- Department of Plant Physiology and Biochemistry, Faculty of Biology, St. Petersburg State University, 199034 St. Petersburg, Russia; (N.Y.); (V.L.)
- Vavilov Institute of General Genetics RAS, St. Petersburg Branch, 199034 St. Petersburg, Russia
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Maneffa AJ, Whitwood AC, Whitehouse AS, Powell H, Clark JH, Matharu AS. Unforeseen crystal forms of the natural osmolyte floridoside. Commun Chem 2020; 3:128. [PMID: 36703387 PMCID: PMC9814874 DOI: 10.1038/s42004-020-00376-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 08/14/2020] [Indexed: 01/29/2023] Open
Abstract
Floridoside (2-α-O-D-galactopyranosyl glycerol) is a glycerol glycoside that is biosynthesised by most species of red algae and has been implicated as an intracellular regulator of various homeostatic functions. Here, we report the identification of two unforeseen crystal forms of the ubiquitous natural osmolyte floridoside including a seemingly unheralded second anhydrous conformational polymorph and the unambiguous description of an elusive monohydrated variant. By employing a variety of thermal and spectroscopic techniques, we begin to explore both their macro and molecular physicochemical properties, which are notably different to that of the previously reported polymorph. This work advances the characterisation of this important natural biomolecule which could aid in facilitating optimised utilisation across a variety of anthropocentric applications and improve comprehension of its role in-vivo as a preeminent compatible solute.
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Affiliation(s)
- Andrew J. Maneffa
- grid.5685.e0000 0004 1936 9668Green Chemistry Centre of Excellence, Department of Chemistry, University of York, Heslington, York YO10 5DD UK
| | - Adrian C. Whitwood
- grid.5685.e0000 0004 1936 9668Department of Chemistry, University of York, Heslington, York YO10 5DD UK
| | - A. Steve Whitehouse
- Nestlé Product Technology Centre (Nestec York Ltd.), Clifton, York YO31 8FY UK
| | - Hugh Powell
- Nestlé Product Technology Centre (Nestec York Ltd.), Clifton, York YO31 8FY UK
| | - James H. Clark
- grid.5685.e0000 0004 1936 9668Green Chemistry Centre of Excellence, Department of Chemistry, University of York, Heslington, York YO10 5DD UK
| | - Avtar S. Matharu
- grid.5685.e0000 0004 1936 9668Green Chemistry Centre of Excellence, Department of Chemistry, University of York, Heslington, York YO10 5DD UK
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Sun M, Zhu Z, Chen J, Yang R, Luo Q, Wu W, Yan X, Chen H. Putative trehalose biosynthesis proteins function as differential floridoside-6-phosphate synthases to participate in the abiotic stress response in the red alga Pyropia haitanensis. BMC PLANT BIOLOGY 2019; 19:325. [PMID: 31324146 PMCID: PMC6642608 DOI: 10.1186/s12870-019-1928-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 07/08/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND The heteroside floridoside is a primary photosynthetic product that is known to contribute to osmotic acclimation in almost all orders of Rhodophyta. However, the encoding genes and enzymes responsible for the synthesis of floridoside and its isomeric form, L- or D-isofloridoside, are poorly studied. RESULTS Here, four putative trehalose-6-phosphate synthase (TPS) genes, designated as PhTPS1, PhTPS2, PhTPS3, and PhTPS4, were cloned and characterized from the red alga Pyropia haitanensis (Bangiophyceae). The deduced amino acid sequence is similar to the annotated TPS proteins of other organisms, especially the UDP-galactose substrate binding sites of PhTPS1, 2, which are highly conserved. Of these, PhTPS1, 4 are involved in the biosynthesis of floridoside and isofloridoside, with isofloridoside being the main product. PhTPS3 is an isofloridoside phosphate synthase, while PhTPS2 exhibits no activity. When challenged by desiccation, high temperature, and salt stress, PhTPS members were expressed to different degrees, but the responses to thermal stress and desiccation were stronger. CONCLUSIONS Thus, in P. haitanensis, PhTPSs encode the enzymatical activity of floridoside and isofloridoside phosphate synthase and are crucial for the abiotic stress defense response.
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Affiliation(s)
- Minxiu Sun
- Key Laboratory of Marine Biotechnology of Zhejiang Province, Ningbo University, Post Box 71, Ningbo, 315211 Zhejiang Province China
| | - Zhujun Zhu
- Ningbo Institute of Oceanography, Ningbo, 315832 Zhejiang China
| | - Juanjuan Chen
- Key Laboratory of Marine Biotechnology of Zhejiang Province, Ningbo University, Post Box 71, Ningbo, 315211 Zhejiang Province China
| | - Rui Yang
- Key Laboratory of Marine Biotechnology of Zhejiang Province, Ningbo University, Post Box 71, Ningbo, 315211 Zhejiang Province China
| | - Qijun Luo
- Key Laboratory of Marine Biotechnology of Zhejiang Province, Ningbo University, Post Box 71, Ningbo, 315211 Zhejiang Province China
| | - Wei Wu
- Key Laboratory of Marine Biotechnology of Zhejiang Province, Ningbo University, Post Box 71, Ningbo, 315211 Zhejiang Province China
| | - Xiaojun Yan
- Key Laboratory of Marine Biotechnology of Zhejiang Province, Ningbo University, Post Box 71, Ningbo, 315211 Zhejiang Province China
| | - Haimin Chen
- Key Laboratory of Marine Biotechnology of Zhejiang Province, Ningbo University, Post Box 71, Ningbo, 315211 Zhejiang Province China
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Davey MP, Norman L, Sterk P, Huete‐Ortega M, Bunbury F, Loh BKW, Stockton S, Peck LS, Convey P, Newsham KK, Smith AG. Snow algae communities in Antarctica: metabolic and taxonomic composition. THE NEW PHYTOLOGIST 2019; 222:1242-1255. [PMID: 30667072 PMCID: PMC6492300 DOI: 10.1111/nph.15701] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 01/08/2019] [Indexed: 05/20/2023]
Abstract
Snow algae are found in snowfields across cold regions of the planet, forming highly visible red and green patches below and on the snow surface. In Antarctica, they contribute significantly to terrestrial net primary productivity due to the paucity of land plants, but our knowledge of these communities is limited. Here we provide the first description of the metabolic and species diversity of green and red snow algae communities from four locations in Ryder Bay (Adelaide Island, 68°S), Antarctic Peninsula. During the 2015 austral summer season, we collected samples to measure the metabolic composition of snow algae communities and determined the species composition of these communities using metabarcoding. Green communities were protein-rich, had a high chlorophyll content and contained many metabolites associated with nitrogen and amino acid metabolism. Red communities had a higher carotenoid content and contained more metabolites associated with carbohydrate and fatty acid metabolism. Chloromonas, Chlamydomonas and Chlorella were found in green blooms but only Chloromonas was detected in red blooms. Both communities also contained bacteria, protists and fungi. These data show the complexity and variation within snow algae communities in Antarctica and provide initial insights into the contribution they make to ecosystem functioning.
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Affiliation(s)
- Matthew P. Davey
- Department of Plant SciencesUniversity of CambridgeCambridgeCB2 3EAUK
| | - Louisa Norman
- Department of Plant SciencesUniversity of CambridgeCambridgeCB2 3EAUK
| | - Peter Sterk
- Cambridge Institute for Medical ResearchUniversity of CambridgeWellcome Trust MRC Building, Hills RoadCambridgeCB2 0QQUK
| | | | - Freddy Bunbury
- Department of Plant SciencesUniversity of CambridgeCambridgeCB2 3EAUK
| | | | - Sian Stockton
- Department of Plant SciencesUniversity of CambridgeCambridgeCB2 3EAUK
| | - Lloyd S. Peck
- British Antarctic SurveyNERCMadingley RoadCambridgeCB3 0ETUK
| | - Peter Convey
- British Antarctic SurveyNERCMadingley RoadCambridgeCB3 0ETUK
| | | | - Alison G. Smith
- Department of Plant SciencesUniversity of CambridgeCambridgeCB2 3EAUK
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Ochsenkühn MA, Röthig T, D’Angelo C, Wiedenmann J, Voolstra CR. The role of floridoside in osmoadaptation of coral-associated algal endosymbionts to high-salinity conditions. SCIENCE ADVANCES 2017; 3:e1602047. [PMID: 28835914 PMCID: PMC5559212 DOI: 10.1126/sciadv.1602047] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 07/19/2017] [Indexed: 05/12/2023]
Abstract
The endosymbiosis between Symbiodinium dinoflagellates and stony corals provides the foundation of coral reef ecosystems. The survival of these ecosystems is under threat at a global scale, and better knowledge is needed to conceive strategies for mitigating future reef loss. Environmental disturbance imposing temperature, salinity, and nutrient stress can lead to the loss of the Symbiodinium partner, causing so-called coral bleaching. Some of the most thermotolerant coral-Symbiodinium associations occur in the Persian/Arabian Gulf and the Red Sea, which also represent the most saline coral habitats. We studied whether Symbiodinium alter their metabolite content in response to high-salinity environments. We found that Symbiodinium cells exposed to high salinity produced high levels of the osmolyte 2-O-glycerol-α-d-galactopyranoside (floridoside), both in vitro and in their coral host animals, thereby increasing their capacity and, putatively, the capacity of the holobiont to cope with the effects of osmotic stress in extreme environments. Given that floridoside has been previously shown to also act as an antioxidant, this osmolyte may serve a dual function: first, to serve as a compatible organic osmolyte accumulated by Symbiodinium in response to elevated salinities and, second, to counter reactive oxygen species produced as a consequence of potential salinity and heat stress.
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Affiliation(s)
- Michael A. Ochsenkühn
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Division of Science and Engineering, New York University Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Till Röthig
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Cecilia D’Angelo
- Coral Reef Laboratory/Institute for Life Sciences, Ocean and Earth Science, University of Southampton, Southampton, UK
| | - Jörg Wiedenmann
- Coral Reef Laboratory/Institute for Life Sciences, Ocean and Earth Science, University of Southampton, Southampton, UK
| | - Christian R. Voolstra
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Corresponding author.
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Chen J, Song D, Luo Q, Mou T, Yang R, Chen H, He S, Yan X. Determination of Floridoside and Isofloridoside in Red Algae by High-Performance Liquid Chromatography–Tandem Mass Spectrometry. ANAL LETT 2014. [DOI: 10.1080/00032719.2014.905950] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Different responses to heat shock stress revealed heteromorphic adaptation strategy of Pyropia haitanensis (Bangiales, Rhodophyta). PLoS One 2014; 9:e94354. [PMID: 24709783 PMCID: PMC3978056 DOI: 10.1371/journal.pone.0094354] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 03/14/2014] [Indexed: 01/12/2023] Open
Abstract
Pyropia has a unique heteromorphic life cycle with alternation stages between thallus and conchocelis, which lives at different water temperatures in different seasons. To better understand the different adaptation strategies for temperature stress, we tried to observe comparative biochemical changes of Pyropia haitanensis based on a short term heat shock model. The results showed that: (1) At normal temperature, free-living conchocelis contains significantly higher levels of H2O2, fatty acid-derived volatiles, the copy number of Phrboh and Phhsp70 genes,the activities of NADPH oxidase and floridoside than those in thallus. The released H2O2 and NADPH oxidase activity of conchocelis were more than 7 times higher than those of thallus. The copy number of Phrboh in conchocelis was 32 times that in thallus. (2) After experiencing heat shock at 35°C for 30 min, the H2O2 contents, the mRNA levels of Phrboh and Phhsp70, NADPH oxidase activity and the floridoside content in thallus were all significantly increased. The mRNA levels of Phrboh increased 5.78 times in 5 min, NADPH oxidase activity increased 8.45 times in 20 min. (3) Whereas, in conchocelis, the changes in fatty acids and their down-stream volatiles predominated, significantly increasing levels of saturated fatty acids and decreasing levels of polyunsaturated fatty acids occurred, and the 8-carbon volatiles were accumulated. However, the changes in H2O2 content and expression of oxidant-related genes and enzymatic activity were not obvious. Overall, these results indicate that conchocelis maintains a high level of active protective apparatus to endure its survival at high temperature, while thallus exhibit typical stress responses to heat shock. It is concluded that Pyropia haitanensis has evolved a delicate strategy for temperature adaptation for its heteromorphic life cycle.
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Leya T. Snow Algae: Adaptation Strategies to Survive on Snow and Ice. CELLULAR ORIGIN, LIFE IN EXTREME HABITATS AND ASTROBIOLOGY 2013. [DOI: 10.1007/978-94-007-6488-0_17] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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12
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Gustavs L, Eggert A, Michalik D, Karsten U. Physiological and biochemical responses of green microalgae from different habitats to osmotic and matric stress. PROTOPLASMA 2010; 243:3-14. [PMID: 19585217 DOI: 10.1007/s00709-009-0060-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Accepted: 06/10/2009] [Indexed: 05/27/2023]
Abstract
Growth of five aeroterrestrial green algal strains (Trebouxiophyceae) in response to changing water availabilities-caused by osmotic (ionic) and matric (desiccation) stresses-was investigated in comparison with a freshwater and a marine strain. All investigated algae displayed good growth under brackish conditions while four out of the five aeroterrestrial strains even grew well under full marine conditions (28-40 psu). The comparison between growth responses in liquid medium, on solid agarose, and on glass fiber filters at 100% air humidity indicated a broad growth tolerance of aeroterrestrial algae towards diminished water availability. While two aeroterrestrial strains even grew better on solid medium which mimics natural biofilm conditions, the aquatic strains showed significant growth inhibition under matric stress. Except Stichococcus sp., which contained the C6-polyol sorbitol, all other aeroterrestrial green algae investigated synthesized and accumulated the C5-polyol ribitol in response to osmotic stress. Using (13)C NMR spectroscopy and HPLC, it could be verified that ribitol functions as an osmotically regulated organic solute. This is the first proof of ribitol in free-living aeroterrestrial green algae. The biochemical capability to synthesize polyols under environmental stress conditions seems to support algal life outside aquatic habitats.
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Affiliation(s)
- Lydia Gustavs
- Department of Biological Sciences, Applied Ecology, University of Rostock, Albert-Einstein-Strasse 3, 18051 Rostock, Germany.
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