The amino acid and sugar composition of diatom cell-walls

Hecky, R.E.; Mopper, Kenneth; Kilham, Peter; Degens, Egon T.

doi:10.1007/bf00348902

Cited by 521 publications

(332 citation statements)

References 16 publications

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“…The good correlation of the kinetic rate constants k andk indicates that the kinetics of BSi dissolution is related to the kinetics of OM degradation, rather than to an intrinsic property of the solid BSi phase, as the latter would require a close coupling of BSi and OM in the particle downflux, which is not the case. Further investigations that integrate studies on how BSi and OM are associated within particles (Schrader, 1971;Tande and Slagstad, 1985;Ragueneau et al, 2002), the structure of diatom skeletons (Hecky et al, 1973;Wetherbee et al, 2000;Volcani, 2002), and models on the use and spreading of hydrolytic enzymes by bacteria (Vetter et al, 1998;Rothman and Forney, 2007) are necessary to elucidate the conditions under which bacteria may mediate BSi dissolution, and the low impact of sediment opal contents on its dissolution rate.…”

Section: Kinetics and Reactive Surface Areamentioning

confidence: 99%

“…Heterotrophic bacteria use exoenzymes for the extracellular degradation of highly polymeric substrates into macronutrients that can be assimilated. The exoenzymes may also attack organic components (not coatings) of the diatom frustule that have been integrated into the BSi matrix during valve morphogenesis (Hecky et al, 1973;Kröger et al, 2002;Volcani, 2002) and may act as corrosion inhibitors (Picket-Heaps et al, 1990;Wetherbee et al, 2000). Upon destruction of the protecting organic substances, the BSi dissolution rate should be notably enhanced.…”

Section: How Bacteria May Contribute To Bsi Dissolutionmentioning

confidence: 99%

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Microbial mediation of benthic biogenic silica dissolution

Holstein

Hensen

2009

Geo-Mar Lett

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Pore water profiles from 24 stations in the South Atlantic (located in the Guinea, Angola, Cape, Guyana, and Argentine basins) show good correlations of oxygen and silicon, suggesting microbially mediated dissolution of biogenic silica. We used simple analytical transport and reaction models to show the tight coupling of the reconstructed process kinetics of aerobic respiration and silicon regeneration. A generic transport and reaction model successfully reproduced the majority of Si pore water profiles from aerobic respiration rates, confirming that the dissolution of biogenic silica (BSi) occurs proportionally to O 2 consumption. Possibly limited to well-oxygenated sediments poor in BSi, benthic Si fluxes can be inferred from O 2 uptake with satisfactory accuracy. Compared to aerobic respiration kinetics, the solubility of BSi emerged as a less influential parameter for silicon regeneration. Understanding the role of bacteria for silicon regeneration requires further investigations, some of which are outlined. The proposed aerobic respiration control of benthic silicon cycling is suitable for benthic-pelagic models. The empirical relation of BSi dissolution to aerobic respiration can be used for regionalization assessments and estimates of the silicon budget to increase the understanding of global primary and export production patterns.

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Section: Kinetics and Reactive Surface Areamentioning

confidence: 99%

Section: How Bacteria May Contribute To Bsi Dissolutionmentioning

confidence: 99%

Microbial mediation of benthic biogenic silica dissolution

Holstein

Hensen

2009

Geo-Mar Lett

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“…4A, asterisks). We consider these changes likely to be important because hydroxyls have been implicated previously as surface functional groups capable of guiding mineral oxide deposition (25,29,30,38).…”

Section: Resultsmentioning

confidence: 99%

Evolutionary selection of enzymatically synthesized semiconductors from biomimetic mineralization vesicles

Bawazer

Izumi

Kolodin

et al. 2012

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

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The way nature evolves and sculpts materials using proteins inspires new approaches to materials engineering but is still not completely understood. Here, we present a cell-free synthetic biological platform to advance studies of biologically synthesized solid-state materials. This platform is capable of simultaneously exerting many of the hierarchical levels of control found in natural biomineralization, including genetic, chemical, spatial, structural, and morphological control, while supporting the evolutionary selection of new mineralizing proteins and the corresponding genetically encoded materials that they produce. DNA-directed protein expression and enzymatic mineralization occur on polystyrene microbeads in waterin-oil emulsions, yielding synthetic surrogates of biomineralizing cells that are then screened by flow sorting, with light-scattering signals used to sort the resulting mineralized composites differentially. We demonstrate the utility of this platform by evolutionarily selecting newly identified silicateins, biomineralizing enzymes previously identified from the silica skeleton of a marine sponge, for enzyme variants capable of synthesizing silicon dioxide (silica) or titanium dioxide (titania) composites. Mineral composites of intermediate strength are preferentially selected to remain intact for identification during cell sorting, and then to collapse postsorting to expose the encoding genes for enzymatic DNA amplification. Some of the newly selected silicatein variants catalyze the formation of crystalline silicates, whereas the parent silicateins lack this ability. The demonstrated bioengineered route to previously undescribed materials introduces in vitro enzyme selection as a viable strategy for mimicking genetic evolution of materials as it occurs in nature. directed evolution | in vitro compartmentalization | DNA shuffling | metal oxide nanoparticles | self-assembly

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“…Particle quality-In diatoms, glycine and serine are concentrated in the cell wall and are comparatively unreactive compared to glutamic acid, tyrosine, phenylalanine, and methionine, which is generally more concentrated in the cell interior (Hecky et al 1973). In several sediment trap studies, it has been demonstrated that the relative glycine content increases with water depth (Degens 1970;Siezen and Mague 1978;Lee et al 1987;Burdige and Martens 1988), and the relative increase can consequently be used for the effect of decomposition processes in the particles.…”

Section: Discussionmentioning

confidence: 99%

Use of amino acid composition to investigate settling and resuspension of a spring bloom in the southern Skagerrak

Petersson¹,

Floderus²

2001

Limnology & Oceanography

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Short-term changes in amino acid composition of near-bed particulate flux were studied at an upper shelf location in the southern Skagerrak, 55 m deep. Sediment trap samples were collected with a 3-d sampling interval from late April to late June 1992. A high settling rate (85 g m Ϫ2 d Ϫ1 ) was intercepted in May, coinciding with high shear velocity and settling of fresh phytoplankton. During the peak in the settling rate, a decrease in the mole percentage of glycine was noticed. At the end of June, smaller peaks of high flux corresponded to periods of increased shear velocity; during this time, the amino acid composition did not change. A Q-mode factor analysis on the amino acid variation of collected particles showed a relation between certain samples consisting of fresh phytoplankton material. If organic carbon is compared to the shear velocity, the related phytoplankton samples had a positive correlation, whereas the more degraded samples had a negative correlation. The observed patterns suggest a coupling between food web dynamics and particle composition on the one hand and availability of benthic fluff at the sediment surface on the other. The length of the period affected by fresh material could be sorted out by using the amino acid composition and be made comparable to samples influenced by more degraded material.Shelves and slopes are highly dynamic environments where the chemical composition of settling particulate matter and the movement of phytoplankton through the water column is controlled by physical processes such as turbulence, advection, gravitational sinking, and sorting, especially during bloom periods in spring and late summer (Riegman et al. 1993). The water content and consistency of the sediment surface layer change because of different conditions, and a surficial fluff layer, benthic fluff, can develop when sedimentation is greater than erosion. Newly settled material with a high water content and/or material with a low density results in benthic fluff that is less resistant to erosion. Jago and Jones (1998) showed that during periods with strong bottom currents, the supply of resuspendable material on the bottom limits the amount being resuspended and transported.

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The amino acid and sugar composition of diatom cell-walls

Cited by 521 publications

References 16 publications

Microbial mediation of benthic biogenic silica dissolution

Microbial mediation of benthic biogenic silica dissolution

Evolutionary selection of enzymatically synthesized semiconductors from biomimetic mineralization vesicles

Use of amino acid composition to investigate settling and resuspension of a spring bloom in the southern Skagerrak

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