Changes in subcellular metal partitioning in the gills of freshwater bivalves (Pyganodon grandis) living along an environmental cadmium gradient

1999 ◽  
Vol 56 (5) ◽  
pp. 774-784 ◽  
Author(s):  
Dacheng Wang ◽  
Yves Couillard ◽  
G C Campbell ◽  
Pierre Jolicoeur
Keyword(s):  
Mining Area ◽  
Size Exclusion ◽  
Metal Exposure ◽  
Relative Molecular Mass ◽  
Biological Organization ◽  
Freshwater Bivalve ◽  
Exclusion Chromatography ◽  
Saturation Method ◽  
Pyganodon Grandis ◽  
Different Levels

To test the response of the freshwater bivalve Pyganodon grandis to increased metal exposure in the field, specimens were collected from 10 lakes located along a known metal gradient in a mining area in northwestern Québec. Total gill concentrations of metallothionein (MT) were determined by the 203Hg saturation method for molluscs from each lake, and the distribution of Cd among various cytosolic ligands, including MT, was determined by size-exclusion chromatography. Gill MT concentrations responded to environmental exposure to Cd but not to Cu or Zn exposure; these spatial variations along the Cd gradient were more important than the seasonal summer variations in gill MT concentrations. Bivalves exposed to concentrations of dissolved free Cd2+ higher than ~1 nM in the external medium exhibited a marked increase of Cd in the low relative molecular mass ligand pool. Symptoms of toxic effects at different levels of biological organization were associated with this biochemical anomaly.

Field transplantation of a freshwater bivalve, Pyganodon grandis, across a metal contamination gradient. I. Temporal changes in metallothionein and metal (Cd, Cu, and Zn) concentrations in soft tissues

1995 ◽  
Vol 52 (4) ◽  
pp. 690-702 ◽  
Author(s):  
Y. Couillard ◽  
P. G. C. Campbell ◽  
A. Tessier ◽  
J. C. Auclair ◽  
J. Pellerin-Massicotte
Keyword(s):  
Soft Tissues ◽  
Shell Growth ◽  
Mining Area ◽  
Metal Exposure ◽  
Steady Increase ◽  
Freshwater Bivalve ◽  
Slow Increase ◽  
Metal Levels ◽  
Pyganodon Grandis ◽  
Over Time

To test the response of the freshwater bivalve Pyganodon grandis (formerly Anodonta grandis) to increased metal exposure in the field, we transferred specimens (8 cm length; 4–6 years old) from a less to a more contaminated lake in the mining area of Rouyn-Noranda, in northwestern Québec. The transplanted bivalves were maintained in open enclosures placed in the bottom sediments of the contaminated lake. Up to 16 individuals were removed from pairs of enclosures at times t = 0 (June 1990), 5, 14, 30, 60, 90, and 400 d; tissue concentrations of metallothionein (MT) and metals were monitored over time. Measurements on control molluscs enclosed in their lake of origin showed that enclosure per se had no apparent effect on tissue [MT] or tissue metal levels, but did decrease shell growth. Metallothionein levels in specimens transplanted to the more contaminated lake showed a slow but steady increase with time; in contrast, MT levels in the control populations showed only modest seasonal fluctuations. The increase in MT over time in the transplanted bivalves was closely correlated with a similar slow increase in soft tissue [Cd]. We conclude that MT in the freshwater bivalve P. grandis is a promising biochemical indicator of metal exposure.

Field transplantation of a freshwater bivalve, Pyganodon grandis, across a metal contamination gradient. II. Metallothionein response to Cd and Zn exposure, evidence for cytotoxicity, and links to effects at higher levels of biological organization

1995 ◽  
Vol 52 (4) ◽  
pp. 703-715 ◽  
Author(s):  
Y. Couillard ◽  
P. G. C. Campbell ◽  
J. G. Auclair ◽  
J. Pellerin-Massicotte
Keyword(s):  
Gill Tissue ◽  
Weight Fraction ◽  
Condition Index ◽  
Mining Area ◽  
Low Molecular Weight ◽  
Biological Organization ◽  
Freshwater Bivalve ◽  
Cellular Toxicity ◽  
Pyganodon Grandis ◽  
Anodonta Grandis

To examine links between the metallothionein (MT) status of an organism and its general health, we transplanted adult specimens of the freshwater bivalve Pyganodon grandis (formerly Anodonta grandis) from a less to a more contaminated lake in the mining area of Rouyn-Noranda, in northwestern Québec. The transplanted bivalves were maintained in open enclosures placed in the bottom sediments of the contaminated lake; in addition, indigenous specimens were maintained in control enclosures in their lake of origin. Up to 16 individuals were removed from pairs of enclosures at times t = 0 (June 1990), 5, 14, 30, 60, 90, and 400 d. Excised gill tissue was analyzed for metallothionein, Cd, Cu, Zn, Ca, and malondialdehyde (MDA), a product of lipid peroxidation. Metal partitioning in the gill cytosol, as determined on a subset of gill samples from transplanted molluscs, changed markedly during the experiment. After 400 d, Cd was present in the low molecular weight fraction of the gill cytosol, and symptoms of cellular toxicity were detected in the transplanted molluscs (elevated [MDA] and [Ca]). At the whole organism level, the marked transplanted bivalves grew more slowly over the 400-d experiment than did marked control bivalves in Lake Opasatica, and their condition index deteriorated over time.

scholarly journals Homodimerization of calpain 3 penta-EF-hand domain

2005 ◽  
Vol 388 (2) ◽  
pp. 585-591 ◽  
Author(s):  
Ravikiran RAVULAPALLI ◽  
Beatriz GARCIA DIAZ ◽  
Robert L. CAMPBELL ◽  
Peter L. DAVIES
Keyword(s):  
Skeletal Muscle ◽  
Molecular Modelling ◽  
Analytical Ultracentrifugation ◽  
Domain Size ◽  
Small Subunit ◽  
Size Exclusion ◽  
Relative Molecular Mass ◽  
Calpain 3 ◽  
Ef Hand ◽  
Exclusion Chromatography

Calpains 1 and 2 are heterodimeric proteases in which large (relative molecular mass Mr 80000) and small (Mr 28000) subunits are linked through their respective PEF (penta-EF-hand) domains. The skeletal muscle-specific calpain 3 is believed not to form a heterodimer with the small subunit but might homodimerize through its PEF domain. Size-exclusion chromatography and analytical ultracentrifugation of the recombinant PEF domain of calpain 3 show that it forms a stable homodimer that does not dissociate on dilution. Molecular modelling suggests that there would be no barriers to the dimerization of the whole enzyme through the PEF domains. This orientation would place the catalytic centres at opposite ends of the dimer.

CHARACTERIZATION OF A NEW LCAT MUTATION CAUSING FAMILIAL LCAT DEFICIENCY (FLD) AND THE ROLE OF APOE AS A MODIFIER GENE OF THE FLD PHENOTYPE

2009 ◽  
Vol 32 (6S) ◽  
pp. 3
Author(s):  
A Baass ◽  
H Wassef ◽  
M Tremblay ◽  
L Bernier ◽  
R Dufour ◽  
...  
Keyword(s):  
Modifier Gene ◽  
Size Exclusion ◽  
Plasma Lipoproteins ◽  
Lipoprotein Profile ◽  
Exclusion Chromatography ◽  
Low Hdl ◽  
Lcat Deficiency ◽  
Apoe Genotypes

Introduction: LCAT (lecithin:cholesterol acyltransferase ) is an enzyme which plays an essential role in cholesterol esterification and reverse cholesterol transport. Familial LCAT deficiency (FLD) is a disease characterized by a defect in LCAT resulting in extremely low HDL-C, premature corneal opacities, anemia as well as proteinuria and renal failure. Method: We have identified two brothers presenting characteristics of familial LCAT deficiency. We sequenced the LCAT gene, measured the lipid profile as well as the LCAT activity in 15 members of this kindred. We also characterized the plasma lipoproteins by agarose gel electrophoresis and size exclusion chromatography and sequenced several candidate genes related to dysbetalipoproteinemia in this family. Results: We have identified the first French Canadian kindred with familial LCAT deficiency. Two brothers affected by FLD, were homozygous for a novel LCAT mutation. This c.102delG mutation occurs at the codon for His35 causing a frameshift that stops transcription at codon 61 abolishing LCAT enzymatic activity both in vivo and in vitro. It has a dramatic effect on the lipoprotein profile, with an important reduction of HDL-C in both heterozygotes (22%) and homozygotes (88%) and a significant decrease in LDL-C in heterozygotes (35%) as well as homozygotes (58%). Furthermore, the lipoprotein profile differed markedly between the two affected brothers who had different APOE genotypes. We propose that APOE could be an important modifier gene explaining heterogeneity in lipoprotein profiles observed among FLD patients. Our results suggest that a LCAT-/- genotype associated with an APOE ?2 allele could be a novel mechanism leading to dysbetalipoproteinemia.

Structure of a shear-thickening polysaccharide extracted from the New Zealand black tree fern, Cyathea medullaris

2020 ◽  
Author(s):  
M Wee ◽  
M Mastrangelo ◽  
Susan Carnachan ◽  
Ian Sims ◽  
K Goh
Keyword(s):  
New Zealand ◽  
Uronic Acid ◽  
Average Molecular Weight ◽  
Shear Thickening ◽  
Water Soluble ◽  
Size Exclusion ◽  
Resonance Spectroscopy ◽  
Tree Fern ◽  
13C Nuclear Magnetic Resonance ◽  
Exclusion Chromatography

A shear-thickening water-soluble polysaccharide was purified from mucilage extracted from the fronds of the New Zealand black tree fern (Cyathea medullaris or 'mamaku' in Māori) and its structure characterised. Constituent sugar analysis by three complementary methods, combined with linkage analysis (of carboxyl reduced samples) and 1H and 13C nuclear magnetic resonance spectroscopy (NMR) revealed a glucuronomannan comprising a backbone of 4-linked methylesterified glucopyranosyl uronic acid and 2-linked mannopyranosyl residues, branched at O-3 of 45% and at both O-3 and O-4 of 53% of the mannopyranosyl residues with side chains likely comprising terminal xylopyranosyl, terminal galactopyranosyl, non-methylesterified terminal glucopyranosyl uronic acid and 3-linked glucopyranosyl uronic acid residues. The weight-average molecular weight of the purified polysaccharide was ~1.9×106Da as determined by size-exclusion chromatography coupled with multi-angle laser light scattering (SEC-MALLS). The distinctive rheological properties of this polysaccharide are discussed in relation to its structure. © 2014 Elsevier B.V.

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