Pleuralins are Involved in Theca Differentiation in the Diatom Cylindrotheca fusiformis

Kröger, Nils; Wetherbee, Richard

doi:10.1078/1434-4610-00024

Cited by 104 publications

(101 citation statements)

References 17 publications

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“…Waterkeyn & Beinfait (1987) speculated that the callose formed a permeable seal at sites along the silicified wall at which the plasma membrane may be temporarily exposed to the external medium. Kro¨ger & Wetherbee (2000) also speculated that the callosic strip on the edge of the hypotheca may assist in binding proteins called pleuralins, which appear to play a role in the differentiation of the hypotheca during cell division in C. fusiformis. Although callose deposits represent 1,3-b-glucan that is closely bound to the cell wall, they are a relatively minor component of the cellular glucans and have a different biological function to that of chrysolaminaran.…”

Section: Discussionmentioning

confidence: 99%

The glucans extracted with warm water from diatoms are mainly derived from intracellular chrysolaminaran and not extracellular polysaccharides

Chiovitti

Molino

Crawford

et al. 2004

European Journal of Phycology

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104

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Several recent studies have employed warm-water treatment of diatom cells to extract nominally bound extracellular polymeric substances. Where examined, the dominant neutral sugar in these extracts was glucose. In the present study, we sought to characterize the structure of the glucose-rich polymers in the water extracts of diatoms and to determine the origin of these polymers. The marine diatoms surveyed were Phaeodactylum tricornutum, Cylindrotheca fusiformis, Craspedostauros australis and Thalassiosira pseudonana. A freshwater species, Pinnularia viridis, was also investigated for the dye labelling experiments. Freshly harvested marine diatoms were extracted with water at 308C for 1 h. Constituent monosaccharide analyses showed that glucose was the dominant neutral sugar (80 -95 mol% of the total) in the extracts from three marine species, whereas the P. tricornutum extract contained predominantly ribose, galactose and glucose, and was inferred to be enriched in low-molecular-weight components. Linkage analysis of the constituent monosaccharides and proton nuclear magnetic resonance spectroscopy showed that the glucose in these extracts was derived primarily from 1,3-b-D-glucan. Immunocytochemistry with a monoclonal anti-1,3-b-D-glucan antibody confirmed that the glucan was localized in the vacuoles of diatom cells preserved by freeze-substitution. Nearly all diatom cells incubated with a fluorescent dye, DiBAC 4 (3), during warm water treatment at 308C or 608C incorporated the dye, demonstrating that the membrane integrity of the diatoms was compromised and supporting the contention that intracellular glucan was released during the treatment. In light of these data, the extracellular glucans of diatoms reported in some previous studies are re-interpreted as intracellular chrysolaminaran.

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Section: Discussionmentioning

confidence: 99%

The glucans extracted with warm water from diatoms are mainly derived from intracellular chrysolaminaran and not extracellular polysaccharides

Chiovitti

Molino

Crawford

et al. 2004

European Journal of Phycology

Self Cite

104

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“…Although it is clear that girdle bands are synthesized in an SDV [28,33], mechanisms of formation are not known, nor what constitutes the difference between a girdle band SDV and valve SDV. A first step in understanding the mechanism of formation of girdle bands is to be able to image the object at high resolution-fortunately, AFM allows this.…”

Section: Formation Of Valves In Centric Diatoms Involves Radial Deposmentioning

confidence: 99%

Application of AFM in understanding biomineral formation in diatoms

Hildebrand

Doktycz

Allison

2007

Pflugers Arch - Eur J Physiol

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We review previous work and present new data on the application of atomic force microscopy (AFM) to study biomineral formation in diatoms, unicellular algae that make cell walls of silica. Previous studies examined a small subset of mostly larger diatom species, identifying a prevalence of large particulate silica on the nanoscale. We survey different structures including valves, girdle bands, and elongated spines called setae, in a variety of species, and show a diversity of nano-and meso-scale silica morphologies, even on different portions of the same structure. A general trend of highly organized mesoscale silica structure on the proximal face of cell wall components was observed, with less organized structure occurring on the distal face. The highly organized structures have features suggestive of an underlying linear template, which defines the area of initial silica polymerization. Such features have not been imaged with such clarity previously, demonstrating the advantages of AFM to image small differences in surface morphology and providing new insights and confirming evidence for models of diatom silica structure formation. In addition to its imaging capability, more developed application of AFM to map locations of organic template components on the nanoscale will greatly aid in elucidating mechanisms of diatom biosilica synthesis.

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“…It is possible that Zn incorporation into the frustule might be via one of these HF-or NH 4 Fextractable organic macromolecules. These compounds include some of the major components involved in silica polymerization: silaffins (Kroger et al, 2001(Kroger et al, , 2002Frigeri et al, 2006), long-chain polyamines Ingalls et al, 2004), pleuralins (Kroger et al, 1997;Kroger and Wetherbee, 2000) and several other unidentified molecules (Swift and Wheeler, 1992;Frigeri et al, 2006). Whereas the association of pleuralins with the frustule is due to their high affinity for silica, long chain polyamines and silaffins are thought to be fully encapsulated in the silica spheres (Vrieling et al, 2002).…”

Section: Nature Of Zn Incorporationmentioning

confidence: 99%

Incorporation of zinc into the frustule of the freshwater diatom Stephanodiscus hantzschii

2009

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Zinc incorporation into the frustule (siliceous cell wall) of the freshwater diatom Stephanodiscus hantzschii was studied for Zn 2+ concentrations ranging from 25 pmol L − 1 to 25 nmol L − 1. A sigmoidal dependency was observed between Zn 2+ concentrations in the culture medium and the concentration of Zn in the frustule.Concentrations of intracellular Zn were positively correlated with Zn in the frustule, suggesting that Zn in the frustule originated from intracellular pools. The processes leading to Zn incorporation into the cell wall were examined by determining the role(s) of Si and Mn via competition experiments. Results demonstrated that Zn competed with Mn for incorporation into the frustule. Zn/Si values for S. hantzschii were consistent with field data obtained from Lake Geneva (Switzerland). The study suggests that the Zn content of fossil frustules could be a valuable tool to study past levels of bioavailable Zn in freshwaters.

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Pleuralins are Involved in Theca Differentiation in the Diatom Cylindrotheca fusiformis

Cited by 104 publications

References 17 publications

The glucans extracted with warm water from diatoms are mainly derived from intracellular chrysolaminaran and not extracellular polysaccharides

The glucans extracted with warm water from diatoms are mainly derived from intracellular chrysolaminaran and not extracellular polysaccharides

Application of AFM in understanding biomineral formation in diatoms

Incorporation of zinc into the frustule of the freshwater diatom Stephanodiscus hantzschii

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