Convergence of cellular systems of metal detoxification

Simkiss, K.; Taylor, Marina G.

doi:10.1016/0141-1136(89)90227-4

Cited by 42 publications

(28 citation statements)

References 7 publications

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“…The inverse concentration-dependent accumulation appears to be unique for an organic compound; a brief review of the literature found similar relationships in metal bioaccumulation studies (24,25). Reasons for an inverse relationship in metals are proposed to be related to saturated uptake conditions at higher exposure concentrations (26) and active regulation of metal uptake. Since SMZ may be ionized at environmental pHs, as in the present study, it is possible that it was similarly regulated.…”

Section: Bioavailability Of Sulfamethazinementioning

confidence: 88%

Fate and bioavailability of sulfamethazine in freshwater ecosystems

Henderson

Coats

2009

ACS Symposium Series

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The antibiotic sulfamethazine can be transported from manured fields to surface water bodies. We investigated the degradation, fate, and bioavailability of sulfamethazine in surface water using 14C-U-phenylsulfamethazine in small pond water microcosms. Sulfamethazine dissipated exponentially from the water column, with the majority of loss occurring via movement into the sediment phase. Manure input significantly increased sorption and binding of sulfamethazine residues to the sediment. These results indicate sediment is a potential sink for sulfamethazine and sulfamethazine-related residues, which could have important implications for benthic organisms. Understanding the bioavailability of pharmaceuticals in environmental matrices is particularly important considering they are often in a bioactive form. The bioavailability of sulfamethazine in surface water microcosms was evaluated using Lumbriculus variegatus in a bioassay. Bioconcentration factors (BCFs) were calculated, and a log BCF >2 was observed during aquatic exposure (0.05 mg/l). Interestingly, a significant inverse relationship between exposure concentration and BCF was also noted. Our results indicate the need for further assessment of the bioaccumulation potential of SMZ residues as a result of sediment exposure of benthic invertebrates. The antibiotic sulfamethazine can be transported from manured fields to surface water bodies. We investigated the degradation, fate, and bioavailability of sulfamethazine in surface water using 14 C-U-phenyl-sulfamethazine in small pond water microcosms. Sulfamethazine dissipated exponentially from the water column, with the majority of loss occurring via movement into the sediment phase. Manure input significantly increased sorption and binding of sulfamethazine residues to the sediment. These results indicate sediment is a potential sink for sulfamethazine and sulfamethazine-related residues, which could have important implications for benthic organisms.Understanding the bioavailability of pharmaceuticals in environmental matrices is particularly important considering they are often in a bioactive form. The bioavailability of sulfamethazine in surface water microcosms was evaluated using Lumbriculus variegatus in a bioassay. Bioconcentration factors (BCFs) were calculated, and a log BCF >2 was observed during aquatic exposure (0.05 mg/l). Interestingly, a significant inverse relationship between exposure concentration and BCF was also noted. Our results indicate the need for further assessment of the bioaccumulation potential of SMZ residues as a result of sediment exposure of benthic invertebrates.

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Section: Bioavailability Of Sulfamethazinementioning

confidence: 88%

Fate and bioavailability of sulfamethazine in freshwater ecosystems

Henderson

Coats

2009

ACS Symposium Series

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“…The transfer of metals across the plasma membrane of the cell most likely occurs via facilitated diffusion (Carpene and George, 1981;Vercauteren and Blust, 1999) or by energy-dependent processes (Rainbow and Dallinger, 1993), say: 1) transport by a membraneprotein of relatively wide specificity (Simkiss and Taylor, 1989); 2) transport by intrinsic proteins of the plasma membrane through which metal ions pass selectively (Viarengo, 1989); or 3) endocytosis (Depledge and Rainbow, 1990;Davies et al, 1997).…”

Section: Cellular Uptake Of Metalsmentioning

confidence: 99%

Cellular and subcellular distribution of metals in molluscs

Marigómez

Soto

Cajaraville

et al. 2002

Microscopy Res & Technique

422

202

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The cellular processes involved in metal metabolism in molluscs are reviewed, with emphasis on the contribution of microscopy (AMG, ARG, EPMA, and SIMS) to both basic research of metal cell biology and applied environmental research. In molluscs, metal uptake may occur by facilitated diffusion, active transport, or endocytosis, and can be enhanced by MT synthesis or formation of mineralized granules. In aquatic molluscs, gills constitute a key interface for dissolved metal uptake, where metals are bound to MT, incorporated into lysosomes, and released basally towards the blood plasma and circulating hemocytes. However, particulate metal uptake is mainly achieved via the digestive tract by endocytosis; further metals are transferred first to lysosomes and then to residual bodies, especially in the digestive cells of the digestive gland. Additionally, metals can be accumulated selectively in specific cell types. As ligands pools differ from cell to cell, different metals may be retained in different cell types. Class "a" metals are localized in cells with granules composed of carbonate, oxalate, phosphate, and sulfate (oxygen donors), whereas "b" metals are associated with those cell types rich in sulfur and nitrogen ligands (sulfur donors). In molluscs, oxygen donors occur in connective tissue calcium cells and basophilic cells, whereas sulfur donors are present in digestive cells, podocytes, nephrocytes, and rhogocytes. Hemocytes, which constitute the most relevant system for metal transport between tissues, move around the body and may penetrate tissues and remove metals from the inner medium to be accumulated in lysosomes as nondigested products. Rhogocytes also participate in metal mobilization, accumulation, and release. The assessment of metal levels in target cells of sentinel molluscs by microscopic techniques provides an early-warning measure, with promising applications as an exposure biomarker for environmental monitoring programs.

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“…These deposits have been implicated in metal detoxification mechanisms for invertebrates such as snails and protozoa (Simkiss and Taylor, 1989). Low molecular weight S-binding proteins (phytochelatins in plants and metallothioneins in animals) have recently been studied intensively.…”

Section: Discussionmentioning

confidence: 99%

Mineralogy of Pb-P grains in the roots of Agrostis capillaris L. by ATEM and EXAFS

1999

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Analytical transmission electron microscopy (ATEM) and X-ray absorption spectroscopy (XAS) have been used to determine the mineralogy of Pb-P deposits in the roots of the heavy metal tolerant grass cultivar Agrostis capillaris L. cv. Parys Mountain. The deposits have a pyromorphite (Pbs(PO4)3C1)-type structure and composition although some of the C1 may be substituted by OH. Energy-dispersive mapping under the scanning electron microscope demonstrated that the majority of these deposits are present in the outer cell wall of the epidermis (the outermost la~er of root cells). The phosphate composition of these grains contrasts with the phytate (C6HIsO24P6 2 ) composition of Zn-P deposits observed in similar electron microscopy studies. The physiological role of heavy metal P deposits is unclear. Heavy metal P precipitates may form actively as a tolerance mechanism to heavy metals or passively, sequestering P in a metabolically inactive foma.

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Convergence of cellular systems of metal detoxification

Cited by 42 publications

References 7 publications

Fate and bioavailability of sulfamethazine in freshwater ecosystems

Fate and bioavailability of sulfamethazine in freshwater ecosystems

Cellular and subcellular distribution of metals in molluscs

Mineralogy of Pb-P grains in the roots of Agrostis capillaris L. by ATEM and EXAFS

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