Adhesive Modular Proteins Occur in the Extracellular Mucilage of the Motile, Pennate Diatom Phaeodactylum tricornutum

Dugdale, Tony M.; Willis, Anusuya; Wetherbee, Richard

doi:10.1529/biophysj.106.081687

Cited by 60 publications

(58 citation statements)

References 13 publications

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“…This includes the permanent adhesive pad secreted by the centric diatom Toxarium undulatum [11,12,14] and the temporary adhesive EPS secreted by the motile, pennate diatom Phaeodactylum tricornutum [13]. To date there has been no identification of any protein from the family of structurally homologous proteins that would need to exist in order to explain the observed sawtooth responses of different dimensions found from an increasing number of different natural adhesives.…”

Section: Resultsmentioning

confidence: 99%

“…EPS is therefore considered to be a complex mixture of structural and functional proteins, glycoproteins, and proteoglycans arranged in a 3-D matrix structure. 466 A. S. Mostaert et al While studies continue to attempt chemical characterization of algal EPS, mainly of diatoms [10,11], recent studies [12][13][14][15] have begun to explore the nanomechanical properties of algal adhesives using the atomic force microscope (AFM) [16]. The AFM is a particularly effective tool for measuring the adhesion of nanoscale volumes of material as it relies upon sensitive laser detection of the deflections of a small cantilever-mounted tip, in response to intermolecular forces between the tip and material of interest.…”

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confidence: 99%

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Characterisation of Amyloid Nanostructures in the Natural Adhesive of Unicellular Subaerial Algae

Mostaert

Giordani

Crockett

et al. 2009

The Journal of Adhesion

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The composition and nanoscale mechanical characteristics of the adhesive from two species of subaerial green unicellular microalgae (Chlorophyta), Coccomyxa sp. and Glaphyrella trebouxiodes, have been studied using Raman spectroscopy, chemical staining, and atomic force microscopy (AFM). Raman spectroscopy confirmed the adhesive proteins of both species to be predominantly in ß-sheet conformations and composed of a number of hydrophobic amino acid residues. Chemical staining with Congo red and thioflavin-T dyes further confirmed the presence of amyloid-like structures. Probing the adhesives with AFM revealed highly ordered and repetitive mechanical responses indicative of highly ordered structures within the adhesive. The repetitive nature of the sawtooth response is typical of a ''sacrificial bond'' and ''hidden length'' mechanism, and what wepropose is the result of mechanical manipulation of individual molecules within an intermolecular ß-sheet that makes up the generic amyloid structure. The mechanical data show how amyloid provides cohesive strength to the adhesives, and this intrinsic mechanical property of an amyloid-based adhesive explains the ecological success of attachment of these subaerial microalgae on various surfaces in urban environments. It is unknown to what extent amyloid fibrils occur in algal adhesives, but we postulate that the amyloid structure could provide a widespread mechanism for mechanical strength.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Characterisation of Amyloid Nanostructures in the Natural Adhesive of Unicellular Subaerial Algae

Mostaert

Giordani

Crockett

et al. 2009

The Journal of Adhesion

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“…For this, the surface chemistry of the involved particles is critical, and it is not surprising that different algae are different in this respect. It is outside the scope of this paper to make any analysis of the underlying chemistry, but the flocculation of P. tricornutum at a relatively low pH could be due to adhesive proteins at the cell surface (Dugdale et al 2006). The adhesiveness of the surface can to a large degree be altered by the algae themselves (when healthy), and increasing adhesiveness is an active strategy for some species in order to, e.g., attach to surfaces (Hoagland et al 1993).…”

Section: Discussionmentioning

confidence: 99%

“…obliquus at high pH was studied. The reason behind choosing these species was that adhesive proteins in P. tricornutum have been identified (Dugdale et al 2006), and diatoms in general seem to flocculate at high pH (Knuckey et al 2006). In contrast, previous studies have suggested that S. obliquus does not flocculate very easily at high pH (Lavoie and de la Noüe 1986).…”

Section: Introductionmentioning

confidence: 99%

Inducing autoflocculation in the diatom Phaeodactylum tricornutum through CO2 regulation

2010

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The effect of pH on flocculation was studied using the diatom Phaeodactylum tricornutum and the green algae Scenedesmus cf. obliquus as surrogate species. There was a distinct, species-specific threshold of pH where flocculation started. P. tricornutum started to flocculate at pH 10.5 and S. cf. obliquus at pH 11.3. Above this threshold, settling rates up to 360 cm h −1 were observed for P. tricornutum and the concentrating factor was up to 60-fold. The combined effect of pH, turbulence, and cell density on flocculation of P. tricornutum was additionally studied in a factorial 5 3 -design experiment. pH was the most important factor affecting flocculation, but at the pH threshold (pH 10.5), the concentrating factor was increased by increasing cell density and turbulence. Algae increases the pH during photosynthesis, and the P. tricornutum and S. cf. obliquus cultures increased the pH to a maximum of 10.8 and 9.5, respectively, after discontinuing the CO 2 supply. For P. tricornutum, this was above the flocculation threshold, and rapid settling of this species due to increased pH was observed in a matter of hours after the CO 2 supply was turned off. This could be used as a simple, low-cost, initial dewatering step for this species.

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“…Diatoms responsible for biofouling not only differ in adhesive strength depending on the surface they are exposed to but also in terms of the difference in adhesive strength between species (Holland et al, 2004). The isolate Pt 1.8.6 has been used in nearly all of the P. tricornutum studies described in the literature (Borowitzka & Volcani, 1978;Scala et al, 2002;Montsant et al, 2005;Dugdale et al, 2006). It is from this isolate that the genome has been sequenced and the EST libraries created (Montsant et al, 2005).…”

Section: Discussionmentioning

confidence: 99%

Whole cell adhesion strength of morphotypes and isolates of Phaeodactylum tricornutum (Bacillariophyceae)

Stanley

Callow

2007

European Journal of Phycology

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Adhesion of raphid diatoms to natural surfaces, which is mediated by the secretion of extracellular polymeric substances (EPS), is an important strategy for growth and survival and contributes to the economically important process of biofouling. An understanding of adhesion processes requires that the genes involved in the EPS biosynthetic pathways and their regulation be characterized. Phaeodactylum tricornutum provides a model system in which to do this but the quantitative adhesion characteristics of the various morphotypes and isolates of this species are currently unknown. The present paper reports on the use of a calibrated fully turbulent flow cell to characterize the whole cell adhesion properties of morphotypes and strains of this species. It has been shown that only the oval cell morphotype adheres to a surface. There are strain/isolate differences in adhesion strength: some strains including strain Pt 1.8.6, the genome of which has been sequenced, show adhesion strengths comparable to other raphid diatoms. In common with some other raphid diatom species, adhesion strength of oval cells of some isolates of P. tricornutum was greater on a hydrophobic surface (Silastic T2 silicone elastomer), than on hydrophilic acid-washed glass. These studies provide a baseline for future molecular genetic and gene expression studies.

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Adhesive Modular Proteins Occur in the Extracellular Mucilage of the Motile, Pennate Diatom Phaeodactylum tricornutum

Cited by 60 publications

References 13 publications

Characterisation of Amyloid Nanostructures in the Natural Adhesive of Unicellular Subaerial Algae

Characterisation of Amyloid Nanostructures in the Natural Adhesive of Unicellular Subaerial Algae

Inducing autoflocculation in the diatom Phaeodactylum tricornutum through CO2 regulation

Whole cell adhesion strength of morphotypes and isolates of Phaeodactylum tricornutum (Bacillariophyceae)

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