Structural identification of long-chain polyamines associated with diatom biosilica in a Southern Ocean sediment core

Bridoux, Maxime C.; Ingalls, Anitra E.

doi:10.1016/j.gca.2010.04.010

Cited by 43 publications

(31 citation statements)

References 69 publications

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“…It was previously shown that such treatments do not affect organic components embedded within the silica [28], [29]. After dissolution of the silica with HF following this treatment, we observed no structured organic material, confirming the absence of an insoluble organic matrix trapped inside the silica structure (data not shown).…”

Section: Resultssupporting

confidence: 82%

Characterization and Localization of Insoluble Organic Matrices Associated with Diatom Cell Walls: Insight into Their Roles during Cell Wall Formation

Tesson

Hildebrand

2013

PLoS ONE

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Organic components associated with diatom cell wall silica are important for the formation, integrity, and function of the cell wall. Polysaccharides are associated with the silica, however their localization, structure, and function remain poorly understood. We used imaging and biochemical approaches to describe in detail characteristics of insoluble organic components associated with the cell wall in 5 different diatom species. Results show that an insoluble organic matrix enriched in mannose, likely the diatotepum, is localized on the proximal surface of the silica cell wall. We did not identify any organic matrix embedded within the silica. We also identified a distinct material consisting of glucose polymer with variable localization depending on the species. In some species this component was directly involved in the morphogenesis of silica structure while in others it appeared to be only a structural component of the cell wall. A novel glucose-rich structure located between daughter cells during division was also identified. This work for the first time correlates the structure, composition, and localization of insoluble organic matrices associated with diatom cell walls. Additionally we identified a novel glucose polymer and characterized its role during silica structure formation.

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Section: Resultssupporting

confidence: 82%

Characterization and Localization of Insoluble Organic Matrices Associated with Diatom Cell Walls: Insight into Their Roles during Cell Wall Formation

Tesson

Hildebrand

2013

PLoS ONE

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“…The exact distribution of silica and organic material within the frustule has not been experimentally verified, but it seems to be tightly bound to the silica within the frustule because it survived the cleaning process to remove the organic cellular material. Further evidence for these tight, likely chemical bonds is that active LCPAs were recovered from fossilized diatomaceous material (27,28). A proposed mechanism for the promotion of silica precipitation by LCPAs is the presence of alternating protonated and nonprotonated tertiary amine groups in the polyamine chains, which form strong hydrogen bonds to silicic acid and facilitate the Si-O bond formation (29).…”

Section: Strength Vs Relative Densitymentioning

confidence: 99%

Microstructure provides insights into evolutionary design and resilience of Coscinodiscus sp. frustule

Aitken

Luo

Reynolds

et al. 2016

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

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We conducted in situ three-point bending experiments on beams with roughly square cross-sections, which we fabricated from the frustule of Coscinodiscus sp. We observe failure by brittle fracture at an average stress of 1.1 GPa. Analysis of crack propagation and shell morphology reveals a differentiation in the function of the frustule layers with the basal layer pores, which deflect crack propagation. We calculated the relative density of the frustule to be ∼30% and show that at this density the frustule has the highest strength-to-density ratio of 1,702 kN·m/kg, a significant departure from all reported biologic materials. We also performed nanoindentation on both the single basal layer of the frustule as well as the girdle band and show that these components display similar mechanical properties that also agree well with bending tests. Transmission electron microscopy analysis reveals that the frustule is made almost entirely of amorphous silica with a nanocrystalline proximal layer. No flaws are observed within the frustule material down to 2 nm. Finite element simulations of the threepoint bending experiments show that the basal layer carries most of the applied load whereas stresses within the cribrum and areolae layer are an order of magnitude lower. These results demonstrate the natural development of architecture in live organisms to simultaneously achieve light weight, strength, and exceptional structural integrity and may provide insight into evolutionary design.iatoms are single-cell algae that form a hard cell wall made of a silica/organic composite. The ability to produce a functional biosilica shell presents several natural precedents that fascinate and inspire scientists and engineers. One fascinating aspect of such silica glass shells is their intricate, varied, and detailed architecture. Diatoms are generally classified based on the symmetry of their shells: Centric diatoms display radial symmetry whereas pennate diatoms have bilateral symmetry. Fig. 1A shows a schematic of a typical centric diatom and reveals that the shells are composed of two halves, called frustules, that fit together in a Petri-dish configuration. The frustules are attached to each other around the perimeter of the shell by one or several girdle bands. The frustules are usually porous with pore size and density varying between species. The frustule shell can also be composed of multiple layers with a cellular structure within the shell.The proposed evolutionary functions for these intricate shell designs include nutrient acquisition, control of diatom sinking rate, control of turbulent flow around the cell, and protection from grazing and viral attack (1). Evidence in favor of a protective function is that the degree of shell silification depends on the environment, with greater amounts of silica found in shells grown in a predatory environment (2). As a deterrent to predation, the frustule makes use of an inherently brittle glass as a structurally protective material while balancing other evolutionary pressures. A denser ...

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“…This difference might be attributed to the unique function of PAs in the synthesis of the nano-silicate structure of the diatom cell wall, and in the role of silicate in diatom cell division (Kröger et al 2000, Sumper & Lehmann 2006. The failure to detect extractable PUT and SPD in diatoms during the early stages of log phase growth could be due to the conjugation of PAs into silafins (proteins involved in silica precipitation) or into long-chain polyamines (LCPAs) in the cell wall (Sumper et al 2005, Bridoux & Ingalls 2010. When cells began to die at the end of the stationary phase, PAs (especially PUT) may accumulate intracellularly as a result of low rates of silicate precipitation, or as a result of dissolution of the cell wall and catabolism of cell wall structures, including silafins and LCPAs.…”

Section: Pa Profiles During Growth Of T Pseudonanamentioning

confidence: 99%

“…Specifically, N or P limitation was found to reduce the cell quota of that element in phytoplankton (Johanssen & Granéli 1999). Silica is important to the growth of diatoms because of its role in cell wall structure (Kröger et al 2000, Sumper & Kröger 2004, Bridoux & Ingalls 2010. Since PAs have a high N content (≥2), it is perhaps not surprising that their intracellular concentrations vary with nitrogen availability (Altman & Levin 1993, Minocha et al 2000.…”

Section: Effect Of Environmental Factors On Extractable Pa Pools Of Tmentioning

confidence: 99%

Response of polyamine pools in marine phytoplankton to nutrient limitation and variation in temperature and salinity

Liu¹,

Nishibori²,

Imai³

et al. 2016

Mar. Ecol. Prog. Ser.

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Structural identification of long-chain polyamines associated with diatom biosilica in a Southern Ocean sediment core

Cited by 43 publications

References 69 publications

Characterization and Localization of Insoluble Organic Matrices Associated with Diatom Cell Walls: Insight into Their Roles during Cell Wall Formation

Characterization and Localization of Insoluble Organic Matrices Associated with Diatom Cell Walls: Insight into Their Roles during Cell Wall Formation

Microstructure provides insights into evolutionary design and resilience of Coscinodiscus sp. frustule

Response of polyamine pools in marine phytoplankton to nutrient limitation and variation in temperature and salinity

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