ICE‐BINDING PROTEINS FROM SEA ICE DIATOMS (BACILLARIOPHYCEAE)<sup>1</sup>

Janech, Michael G.; Krell, Andreas; Möck, Thomas; Kang, Jae‐Shin; Raymond, James A.

doi:10.1111/j.1529-8817.2006.00208.x

Cited by 166 publications

(154 citation statements)

References 37 publications

(53 reference statements)

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“…Antarctic phytoplankton species are well adapted to sub-zero temperatures (Morgan-Kiss et al, 2006), having evolved cryoprotectants (Raymond and Knight, 2003) and anti-freeze proteins (Janech et al, 2006). In general, they show higher growth rates and physiological activity than would be expected (Feller and Gerday, 2003;Morgan-Kiss et al, 2006;Young et al, 2015), which may be a form of cold adaptation, where the cell is able to overcome the slow enzymatic rates usually enforced by cold temperatures (Feller and Gerday, 2003;Morgan-Kiss et al, 2006).…”

Section: Temperaturementioning

confidence: 99%

Southern Ocean phytoplankton physiology in a changing climate

Petrou

Kranz

Trimborn

et al. 2016

Journal of Plant Physiology

114

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Please cite this article in press as: Petrou, K., et al., Southern Ocean phytoplankton physiology in a changing climate. J Plant Physiol (2016), http://dx.doi.org/10.1016/j.jplph.2016.05.004 ARTICLE IN PRESS a b s t r a c tThe Southern Ocean (SO) is a major sink for anthropogenic atmospheric carbon dioxide (CO 2 ), potentially harbouring even greater potential for additional sequestration of CO 2 through enhanced phytoplankton productivity. In the SO, primary productivity is primarily driven by bottom up processes (physical and chemical conditions) which are spatially and temporally heterogeneous. Due to a paucity of trace metals (such as iron) and high variability in light, much of the SO is characterised by an ecological paradox of high macronutrient concentrations yet uncharacteristically low chlorophyll concentrations. It is expected that with increased anthropogenic CO 2 emissions and the coincident warming, the major physical and chemical process that govern the SO will alter, influencing the biological capacity and functioning of the ecosystem. This review focuses on the SO primary producers and the bottom up processes that underpin their health and productivity. It looks at the major physico-chemical drivers of change in the SO, and based on current physiological knowledge, explores how these changes will likely manifest in phytoplankton, specifically, what are the physiological changes and floristic shifts that are likely to ensue and how this may translate into changes in the carbon sink capacity, net primary productivity and functionality of the SO.

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Section: Temperaturementioning

confidence: 99%

Southern Ocean phytoplankton physiology in a changing climate

Petrou

Kranz

Trimborn

et al. 2016

Journal of Plant Physiology

114

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“…Furthermore, increases in PUFA composition within the thylakoid membrane enables increased electron flow under light limitation (Mock and Kroon, 2002b), compensates for pigment and protein loss under nitrogen limitation (Mock and Kroon, 2002a), and has been shown to confer salinity tolerance in the freshwater cyanobacterium, Synechocystis (Allakhverdiev et al, 1999). Polar diatoms also produce ice-binding proteins that serve as cryoprotectants via their ability to prevent ice recrystallization (Janech et al, 2006). Secretion of these proteins along with other exopolymeric substances likely serve to maintain brine channel structure (Krembs et al, 2002) and facilitate the retention of brine (Raymond et al, 2009;Krembs et al, 2011;Raymond, 2011).…”

mentioning

confidence: 99%

Proteomic Analysis of a Sea-Ice Diatom: Salinity Acclimation Provides New Insight into the Dimethylsulfoniopropionate Production Pathway

et al. 2011

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Dimethylsulfoniopropionate (DMSP) plays important roles in oceanic carbon and sulfur cycling and may significantly impact climate. It is a biomolecule synthesized from the methionine (Met) pathway and proposed to serve various physiological functions to aid in environmental stress adaptation through its compatible solute, cryoprotectant, and antioxidant properties. Yet, the enzymes and mechanisms regulating DMSP production are poorly understood. This study utilized a proteomics approach to investigate protein changes associated with salinity-induced DMSP increases in the model sea-ice diatom Fragilariopsis cylindrus (CCMP 1102). We hypothesized proteins associated with the Met-DMSP biosynthesis pathway would increase in relative abundance when challenged with elevated salinity. To test this hypothesis axenic log-phase cultures initially grown at a salinity of 35 were gradually shifted to a final salinity of 70 over a 24-h period. Intracellular DMSP was measured and two-dimensional gel electrophoresis was used to identify protein changes at 48 h after the shift. Intracellular DMSP increased by approximately 85% in the hypersaline cultures. One-third of the proteins increased under high salinity were associated with amino acid pathways. Three protein isoforms of S-adenosylhomo-cysteine hydrolase, which synthesizes a Met precursor, increased 1.8-to 2.1-fold, two isoforms of S-adenosyl Met synthetase increased 1.9-to 2.5-fold, and S-adenosyl Met methyltransferase increased by 2.8-fold, suggesting active methyl cycle proteins are recruited in the synthesis of DMSP. Proteins from the four enzyme classes of the proposed algal Met transaminase DMSP pathway were among the elevated proteins, supporting our hypothesis and providing candidate genes for future characterization studies.

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“…These proteins are a subset of an expanding group of identified proteins, whose salient feature is ice binding (3,4). AFPs are characterized by their ability to cause a temperature difference (hysteresis) in the melting and freezing of ice and are classified as hyperactive or moderately active according to the magnitude of their freezing hysteresis (FH) activity (5).…”

mentioning

confidence: 99%

Microfluidic experiments reveal that antifreeze proteins bound to ice crystals suffice to prevent their growth

Celik

Drori

Pertaya-Braun

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

150

142

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Antifreeze proteins (AFPs) are a subset of ice-binding proteins that control ice crystal growth. They have potential for the cryopreservation of cells, tissues, and organs, as well as for production and storage of food and protection of crops from frost. However, the detailed mechanism of action of AFPs is still unclear. Specifically, there is controversy regarding reversibility of binding of AFPs to crystal surfaces. The experimentally observed dependence of activity of AFPs on their concentration in solution appears to indicate that the binding is reversible. Here, by a series of experiments in temperature-controlled microfluidic devices, where the medium surrounding ice crystals can be exchanged, we show that the binding of hyperactive Tenebrio molitor AFP to ice crystals is practically irreversible and that surface-bound AFPs are sufficient to inhibit ice crystal growth even in solutions depleted of AFPs. These findings rule out theories of AFP activity relying on the presence of unbound protein molecules.thermal hysteresis | ice structuring proteins A ntifreeze proteins (AFPs) are found in a variety of coldadapted organisms, where they serve as inhibitors of ice crystal growth and recrystallization (1, 2). These proteins are a subset of an expanding group of identified proteins, whose salient feature is ice binding (3, 4). AFPs are characterized by their ability to cause a temperature difference (hysteresis) in the melting and freezing of ice and are classified as hyperactive or moderately active according to the magnitude of their freezing hysteresis (FH) activity (5). The FH activity is defined as the difference between the melting temperature of ice crystals and the nonequilibrium freezing temperature at which rapid crystal growth commences. Although the FH activity has been investigated for more than four decades, the actual mechanism of action of AFPs is still not clear. This is partly because the interactions between molecules of AFPs, water, and ice at the ice-water interface are difficult to study experimentally due to the delicate, transitory nature of the ice-water interface.FH activity is thought to be due to an adsorption-inhibition mechanism that states that AFPs bind to ice surfaces and allow ice crystal growth only in surface regions between the bound AFP molecules (6, 7). This patchy growth pattern causes increased local microcurvature of the ice front that leads to larger surface energy, making the transformation of water into ice less energetically favorable and thus reducing the freezing temperature (GibbsThompson effect). It has been argued that the binding of AFPs to ice surfaces must be irreversible, because AFP desorption would result in rapid crystal growth in the areas where the AFP molecules have been desorbed from the ice surface (6,8). This theory has been criticized for assuming that the ice-water interface is sharp, contrary to the experimental evidence that the transitions from an ordered solid phase to a liquid phase at the ice-water interfaces are gradual and occur over seve...

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ICE‐BINDING PROTEINS FROM SEA ICE DIATOMS (BACILLARIOPHYCEAE)¹

Cited by 166 publications

References 37 publications

Southern Ocean phytoplankton physiology in a changing climate

Southern Ocean phytoplankton physiology in a changing climate

Proteomic Analysis of a Sea-Ice Diatom: Salinity Acclimation Provides New Insight into the Dimethylsulfoniopropionate Production Pathway

Microfluidic experiments reveal that antifreeze proteins bound to ice crystals suffice to prevent their growth

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ICE‐BINDING PROTEINS FROM SEA ICE DIATOMS (BACILLARIOPHYCEAE)1

Cited by 166 publications

References 37 publications

Southern Ocean phytoplankton physiology in a changing climate

Southern Ocean phytoplankton physiology in a changing climate

Proteomic Analysis of a Sea-Ice Diatom: Salinity Acclimation Provides New Insight into the Dimethylsulfoniopropionate Production Pathway

Microfluidic experiments reveal that antifreeze proteins bound to ice crystals suffice to prevent their growth

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ICE‐BINDING PROTEINS FROM SEA ICE DIATOMS (BACILLARIOPHYCEAE)¹