Molar mass determination of the polysaccharide associated with coccoliths of emiliania huxleyi

Borman, Anton H.; Kok, Dirk J.; Jong, Elisabeth W. de Vrind‐de; Westbroek, Peter; Varkevisser, F.A.; Treslong, C. J. Bloys van; Bosch, L.

doi:10.1016/0014-3057(86)90177-1

Cited by 10 publications

(7 citation statements)

References 10 publications

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“…Coccolith polysaccharides may be the source of newly produced HMW DOM in our experiments based on similar NAld composition of HMW DOM in our study and of coccolith polysaccharides in previous studies (Fichtinger‐Schepman et al ., ; de Jong et al ., ; Borman et al ., ; ). Increasing production rates of NAld's (Table ) during the stationary phase together with the positive correlation between 13 C incorporated into PIC and into HMW ΣNAld (from day 10 to 19: r = 0.77, n = 9, P < 0.05) also suggest coccolith polysaccharides may be the source of newly produced HMW DOM.…”

Section: Discussionmentioning

confidence: 99%

Release of dissolved carbohydrates by Emiliania huxleyi and formation of transparent exopolymer particles depend on algal life cycle and bacterial activity

Oostende

Moerdijk-Poortvliet

Boschker

et al. 2012

Environmental Microbiology

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Summary The coccolithophore Emiliania huxleyi plays a pivotal role in the marine carbon cycle. However, we have only limited understanding of how its life cycle and bacterial interactions affect the production and composition of dissolved extracellular organic carbon and its transfer to the particulate pool. We traced the fate of photosynthetically fixed carbon during phosphate‐limited stationary growth of non‐axenic, calcifying E. huxleyi batch cultures, and more specifically the transfer of this carbon to bacteria and to dissolved high molecular weight neutral aldoses (HMW NAld) and extracellular particulate carbon. We then compared the dynamics of dissolved carbohydrates and transparent exopolymer particles (TEP) between cultures of non‐axenic and axenic diploid E. huxleyi. In addition, we present the first data on extracellular organic carbon in (non‐axenic) haploid E. huxleyi cultures. Bacteria enhanced the accumulation of dissolved polysaccharides and altered the composition of dissolved HMW NAld, while they also stimulated the formation of TEP containing high densities of charged polysaccharides in diploid E. huxleyi cultures. In haploid E. huxleyi cultures we found a more pronounced accumulation of dissolved carbohydrates, which had a different NAld composition than the diploid cultures. TEP formation was significantly lower than in the diploid cultures, despite the presence of bacteria. In diploid E. huxleyi cultures, we measured a high level of extracellular release of organic carbon (34–76%), retrieved mainly in the particulate pool instead of the dissolved pool. Enhanced formation of sticky TEP due to bacteria–alga interactions, in concert with the production of coccoliths, suggests that especially diploid E. huxleyi blooms increase the efficiency of export production in the ocean during dissolved phosphate‐limited conditions.

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Section: Discussionmentioning

confidence: 99%

Release of dissolved carbohydrates by Emiliania huxleyi and formation of transparent exopolymer particles depend on algal life cycle and bacterial activity

Oostende

Moerdijk-Poortvliet

Boschker

et al. 2012

Environmental Microbiology

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“…8 We used a Digital Instruments Multimode IIIa atomic force microscope (AFM) running in contact mode using sharpened tips of Si 3 N 4 with a spring constant of about 0.6 nN. The samples were imaged in a glass fluid cell.…”

Section: Methodsmentioning

confidence: 99%

“…The CAP was isolated from cultures of E. huxleyi by the method described for Pleurochrysis carterae in Marsh et al 4 The molar mass of CAP is 88.6 kDa. 8 We used a Digital Instruments Multimode IIIa atomic force microscope (AFM) running in contact mode using sharpened tips of Si 3 N 4 with a spring constant of about 0.6 nN. The samples were imaged in a glass fluid cell.…”

Section: Methodsmentioning

confidence: 99%

Controlling Biomineralization: The Effect of Solution Composition on Coccolith Polysaccharide Functionality

Henriksen

Stipp

2009

Crystal Growth & Design

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The calcite shields produced by unicellular marine algae demonstrate the remarkable crystal control that organisms can achieve through biomineralization. Emiliania huxleyi produces complex polysaccharides ("coccolith associated polysaccharides", CAP) that regulate crystal morphology by preferentially attaching to calcite acute step edges, thus promoting growth of the specific crystal faces required for design of that species of coccolith. However, to control crystal growth, the alga must be able to control CAP behavior at the local scale, so its functionality can be switched on and off. Here, we show that the functionality of CAP from E. huxleyi depends directly on solution composition. We used atomic force microscopy (AFM) to investigate the behavior of calcite surfaces under varying pH, in the presence of CAP and cations chosen to test the role of ionic potential, that is, charge per unit radius (K + , Na + , Sr 2+ , Ca 2+ , Mg 2+ , Zn 2+ , and Eu 3+ at 1 M charge concentration). Site-specific adsorption to calcite steps, essential for regulating morphology, only occurs in neutral to acidic pH (range investigated: 3.4-7.7) and in the presence of K + , Na + , Sr 2+ , and Ca 2+ . Basic pH (range investigated: 9.9-11.3), or cations of higher ionic potential than Ca (Mg 2+ , Zn 2+ , and Eu 3+ ), caused CAP to ignore step edges, turning off its normal functionality. We propose that complexation between cations, CAP, and the calcite surface controls CAP behavior. Thus, cations provide an on/off switch for CAP function, with the power to regulate and disturb coccolith biomineralization as well as to control calcite growth at the unblocked precipitation sites.

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“…It has a mannose (simple sugar, C 6 H 12 O 6 ) backbone and many side chains of polygalacturonic acid [n(C 6 H 8 O 6 )] and ester-bound sulfate groups (Fichtinger-Shepman et al 1981); the molecular weight is 88.6 kDa (Borman et al 1986). It has the ability to bind Ca 2+ ions, enabling it to inhibit calcite crystallization (Borman et al 1982) and inß uence crystal morphology (Didymus et al 1993).…”

Section: Introductionmentioning

confidence: 97%

Biological control on calcite crystallization: AFM investigation of coccolith polysaccharide function

Henriksen

Stipp

Young

et al. 2004

American Mineralogist

122

128

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Calcite crystals grown by organisms can be elaborate and enigmatic. One of the best examples is the tiny calcite shields known as coccoliths that are produced by unicellular algae. Coccoliths consist of interlocking single crystals of highly modiÞ ed morphology, and complex organic molecules called CAPs (coccolith associated polysaccharides) are known to be intimately associated with their formation. Here, we show how a CAP can regulate crystal morphology to enhance precipitation of speciÞ c faces, a crucial aspect of the biomineralization process.Using atomic force microscopy (AFM), we investigated the interaction of CAP from the species Emiliania huxleyi with the calcite surface during dissolution, precipitation, and dynamic equilibrium. We were able to see the polysaccharide adsorbed to the surface and observe its impact on mineral behavior. These experiments demonstrate that CAP preferentially interacts with surface sites deÞ ned by acute, rather than obtuse, angles and blocks acute sites during dissolution and growth. Therefore, CAP makes the calcite face that is most stable in the pure system, {101-4}, extend preferentially on the obtuse edges, promoting development of faces with lower angles to c-axis. AFM images of E. huxleyi at micrometer and atomic scales established that this is precisely the type of faces that deÞ ne the morphology of the coccolith crystals. Therefore, we propose that crystal shape regulation by CAP is a fundamental aspect of coccolith biomineralization, and that preferential growth inhibition by sitespeciÞ c functional groups is the mechanism causing CAP functionality.

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Molar mass determination of the polysaccharide associated with coccoliths of emiliania huxleyi

Cited by 10 publications

References 10 publications

Release of dissolved carbohydrates by Emiliania huxleyi and formation of transparent exopolymer particles depend on algal life cycle and bacterial activity

Release of dissolved carbohydrates by Emiliania huxleyi and formation of transparent exopolymer particles depend on algal life cycle and bacterial activity

Controlling Biomineralization: The Effect of Solution Composition on Coccolith Polysaccharide Functionality

Biological control on calcite crystallization: AFM investigation of coccolith polysaccharide function

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