Experimental silver bioaccumulation in the polychaetePomatoceros triqueter (L.)

Vovelle, Jean; Grasset, Michèle

doi:10.1007/bf01135387

Cited by 6 publications

(6 citation statements)

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“…The necessity of microion addition for charge equivalence, high polydispersity in molecular weight and negative charges (via phosphorylation), and the effect of divalent ion binding on Pc-3 backbone flexibility all portend a multiphase coacervate morphology. Although this is consistent with the porous structure of the cement (7) and of the mottled cement precursor granules (3,33), a fundamental understanding of the process will require much more study.…”

Section: Discussionmentioning

confidence: 73%

“…Addition of microions such as Mg 2ϩ and Ca 2ϩ to the mixture could help overcome the charge imbalance but high salt also suppresses coacervation (30). Cytochemical studies of cement producing cells in the cement glands of the tubeworms have established that Mg 2ϩ and Ca 2ϩ are colocalized with phosphate in mottled granules (6,33), but it is not known whether Pc-1 and -2 are also present. The emerging picture is one that contrasts starkly with coacervation based on a symmetrical mixture.…”

Section: Discussionmentioning

confidence: 99%

“…In mussel byssal adhesive plaques, diDopa cross-links prevail (15), but whether they also occur in Phragmatopoma cement is not known. A role for phosphoserines in setting is suggested by the high levels of Mg/Ca 2ϩ in the cement and cement gland (6,7,33) and cement softening by EDTA treatment. 5 Indeed, Ca/Mg 2ϩ interactions with phosphates represent an excellent pH triggered type of setting.…”

Section: Discussionmentioning

confidence: 99%

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Cement Proteins of the Tube-building Polychaete Phragmatopoma californica

Zhao

Sun

Stewart

et al. 2005

Journal of Biological Chemistry

269

284

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The mineralized tube of the sandcastle worm Phragmatopoma californica is made from exogenous mineral particles (sand, shell, etc.) glued together with a cement secreted from the "building organ" on the thorax of the worm. The glue is a cross-linked mixture of three highly polar proteins. The complete sequences of Pc-1 (18 kDa) and Pc-2 (21 kDa) were deduced from cDNAs derived from previously reported peptide sequences (Waite, J. H., Jensen, R., and Morse, D. E. (1992) Biochemistry 31, 5733-5738). Both proteins are basic (pI ϳ10) and exhibit Gly-rich peptide repeats. The consensus repeats in Pc-1 and -2 are VGGYGYGGKK (15 times), and HPAVX-HKALGGYG (eight times), respectively, in which X denotes an intervening nonrepeated sequence and Y is modified to 3,4-dihydroxyphenyl-L-alanine (Dopa). The third protein, Pc-3, was deduced from the cement to be about 80 mol % phosphoserine/ serine, and the cDNA was obtained by exploiting the presence of poly-serine repeats. Pc-3 consists of a family of at least seven variants with 60 -90 mol % serine most of which is phosphorylated in the cement. Pc-1, -2, and -3 contain cysteine some of which reacts to form 5-S-cysteinyl-Dopa cross-links during the setting process.The California sandcastle worm, Phragmatopoma californica (Fewkes), is a premier sand mason (1). In common with other sabellariid polychaetes, it exhibits an almost frenzied diligence in the collection, sorting and placement of sand grains for the construction and repair of its tubular home.3 Although each worm builds primarily the tube in which it resides, a colony of worms can coordinate its efforts to erect massive boulder-like concretions that play a pivotal role in reef ecology (3, 4). The cement used by Phragmatopoma and related sabellariids to bind together grains of sand has been of interest for some time in that it adheres irreversibly to wet mineral surfaces and is used with extraordinary speed and economy. Perhaps 4 -7 "spot welds," each about 100 m in diameter, are used to hold each sand grain (diameter 500 m) in place in the natural concrete (3,5).Phragmatopoma cement consists of proteins and significant levels of phosphate, calcium, and magnesium (6, 7). Two of the cement proteins, Pc-1 and Pc-2, 4 known from an earlier partial characterization (8),resemble the byssal adhesives of mussels (9) in that they are basic and contain 3,4-dihydroxyphenyl-L-alanine (Dopa) (5,7,8). Surprisingly, the abundant phosphate was not found to be associated with mineral but rather with serine residues in the cement (7). Indeed, the cement is dominated by phosphoserine and glycine, which together account for nearly 60 mol % of all the residues detected post-hydrolysis. Since the serine content of Pc-1 and -2 is negligible (8), the existence of a third serine-rich precursor is postulated. The aim of the present research was to identify the serine-rich protein, to obtain full-length sequences of Pc-1 and Pc-2, and to gain some insights into the mechanism of cement solidification. MATERIALS AND METHODSWorm Maintenance for Tub...

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Section: Discussionmentioning

confidence: 73%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Cement Proteins of the Tube-building Polychaete Phragmatopoma californica

Zhao

Sun

Stewart

et al. 2005

Journal of Biological Chemistry

269

284

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“…Likewise, AgNPs were identified as resulting from Bacillus subtillus by reduction of Ag ions due to extracellular biosynthesis . Marine polychaetes may isolate Ag metal in vacuoles, presumably as a detoxification mechanism. , Ag from AgNPs was found associated with inorganic granules in estuarine polychaetes . In addition, to having a high Ag metal proportion, worms from the AgNP-citrate treatment had a higher fraction of Ag 2 S than did the AgNP-PVP and AgNO 3 treatments.…”

Section: Resultsmentioning

confidence: 99%

“…22 In addition, to having a high Ag metal proportion, worms from the AgNP-citrate treatment had a higher fraction of Ag 2 S than did the AgNP-PVP and AgNO 3 treatments. This may be a result of sulfur containing metallothionein proteins also used by the worm for detoxification 22,28,29 or may reflect the worm's inability to break down the Ag 2 S-citrate complex compared to Ag 2 S-PVP or Ag 2 S-Ag + complexes.…”

Section: Environmental Science and Technologymentioning

confidence: 99%

Toxicity, Bioaccumulation, and Biotransformation of Silver Nanoparticles in Marine Organisms

Wang

Scheckel

et al. 2014

Environ. Sci. Technol.

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The toxicity, bioaccumulation, and biotransformation of citrate and polyvinylpyrrolidone (PVP) coated silver nanoparticles (NPs) (AgNP-citrate and AgNP-PVP) in marine organisms via marine sediment exposure was investigated. Results from 7-d sediment toxicity tests indicate that AgNP-citrate and AgNP-PVP did not exhibit toxicity to the amphipod (Ampelisca abdita) and mysid (Americamysis bahia) at ≤75 mg/kg dry wt. A 28-d bioaccumulation study showed that Ag was significantly accumulated in the marine polychaete Nereis virens (N. virens) in the AgNP-citrate, AgNP-PVP and a conventional salt (AgNO3) treatments. Synchrotron X-ray absorption spectroscopy (XAS) results showed the distribution of Ag species in marine sediments amended with AgNP-citrate, AgNP-PVP, and AgNO3 was AgCl (50–65%) > Ag2S (32–42%) > Ag metal (Ag0) (3–11%). In N virens, AgCl (25–59%) and Ag2S (10–31%) generally decreased and, Ag metal (32–44%) increased, relative to the sediments. The patterns of speciation in the worm were different depending upon the coating of the AgNP and both types of AgNPs were different than the AgNO3 salt. These results show that the AgNP surface capping agents influenced Ag uptake, biotransformation, and/or excretion. To our knowledge, this is the first demonstration of the bioaccumulation and speciation of AgNPs in a marine organism (N. virens).

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Effects of silver ions (Ag⁺) on contractile ring function and microtubule dynamics during first cleavage in Ilyanassa obsoleta

Conrad¹,

Stephens²,

Paulsen³

et al. 1994

Cell Motil. Cytoskeleton

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The terminal phase of cell division involves tight constriction of the cleavage furrow contractile ring, stabilization/elongation of the intercellular bridge, and final separation of the daughter cells. At first cleavage, the fertilized eggs of the mollusk, Ilyanassa obsoleta, form two contractile rings at right angles to each other in the same cytoplasm that constrict to tight necks and partition the egg into a trefoil shape. The cleavage furrow contractile ring (CF) normally constricts around many midbody microtubules (MTs) and results in cleavage; the polar lobe constriction contractile ring (PLC) normally constricts around very few MTs and subsequently relaxes without cleavage. In the presence of Ag+ ions, the PLC 1) begins MT-dependent rapid constriction sooner than controls, 2) encircles more MTs than control egg PLCs, 3) elongates much more than control PLCs, and 4) remains tightly constricted and effectively cleaves the polar lobe from the egg. If Ag(+)-incubated eggs are returned to normal seawater at trefoil, tubulin fluorescence disappears from the PLC neck and the neck relaxes. If nocodazole, a drug that depolymerizes MTs, is added to Ag(+)-incubated eggs during early PLC constriction, the PLC is not stabilized and eventually relaxes. However, if nocodazole is added to Ag(+)-incubated eggs at trefoil, tubulin fluorescence disappears from the PLC neck but the neck remains constricted. These results suggest that Ag+ accelerates and gradually stabilizes the PLC constriction by a mechanism that is initially MT-dependent, but that progressively becomes MT-independent.

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Experimental silver bioaccumulation in the polychaetePomatoceros triqueter (L.)

Cited by 6 publications

References 9 publications

Cement Proteins of the Tube-building Polychaete Phragmatopoma californica

Cement Proteins of the Tube-building Polychaete Phragmatopoma californica

Toxicity, Bioaccumulation, and Biotransformation of Silver Nanoparticles in Marine Organisms

Effects of silver ions (Ag⁺) on contractile ring function and microtubule dynamics during first cleavage in Ilyanassa obsoleta

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Experimental silver bioaccumulation in the polychaetePomatoceros triqueter (L.)

Cited by 6 publications

References 9 publications

Cement Proteins of the Tube-building Polychaete Phragmatopoma californica

Cement Proteins of the Tube-building Polychaete Phragmatopoma californica

Toxicity, Bioaccumulation, and Biotransformation of Silver Nanoparticles in Marine Organisms

Effects of silver ions (Ag+) on contractile ring function and microtubule dynamics during first cleavage in Ilyanassa obsoleta

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Effects of silver ions (Ag⁺) on contractile ring function and microtubule dynamics during first cleavage in Ilyanassa obsoleta