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.

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.

In Vivo Studies on the Inhibition of Coagulation by Fractionated Heparin and by a Heparin Analogue I. Effects of Heparin Fractions

1981 ◽  
Vol 46 (03) ◽  
pp. 612-616 ◽  
Author(s):  
U Schmitz-Huebner ◽  
L Balleisen ◽  
F Asbeck ◽  
J van de Loo
Keyword(s):  
Molecular Weight ◽  
Day Treatment ◽  
Gel Filtration ◽  
Weight Fraction ◽  
In Vivo Studies ◽  
Low Molecular Weight ◽  
High Molecular Weight Fraction ◽  
Platelet Factor ◽  
Heparin Fractions

SummaryHigh and low molecular weight heparin fractions obtained by gel filtration chromatography of sodium mucosal heparin were injected subcutaneously into six healthy volunteers and compared with the unfractionated substance in a cross-over trial. Equal doses of 5,000 U were administered twice daily over a period of three days and heparin activity was repeatedly controlled before and 2, 4, 8 hrs after injection by means of the APTT, the anti-Xa clotting test and a chromogenic substrate assay. In addition, the in vivo effect of subcutaneously administered fractionated heparin on platelet function was examined on three of the volunteers. The results show that s.c. injections of the low molecular weight fraction induced markedly higher anti-Xa activity than injections of the other preparations. At the same time, APTT results did not significantly differ. Unfractionated heparin and the high molecular weight fraction enhanced ADP-induced platelet aggregation and collagen-mediated MDA production, while the low molecular weight fraction hardly affected these assays, but potently inhibited thrombin-induced MDA production. All heparin preparations stimulated the release of platelet Factor 4 in plasma. During the three-day treatment periods, no side-effects and no significant changes in the response to heparin injections were detected.

scholarly journals Candidate markers for the detection of hepatocellular carcinoma in low-molecular weight fraction of serum

2007 ◽  
Vol 28 (10) ◽  
pp. 2149-2153 ◽  
Author(s):  
Radoslav Goldman ◽  
Habtom W. Ressom ◽  
Mohamed Abdel-Hamid ◽  
Lenka Goldman ◽  
Antai Wang ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Molecular Weight ◽  
Weight Fraction ◽  
Low Molecular Weight

Basal Activity of the Natriuretic Factor Extracted from the Rat Kidney as a Function of the Diet and its Role in the Regulation of the Acute Sodium Balance

1980 ◽  
Vol 58 (5) ◽  
pp. 385-391 ◽  
Author(s):  
F. Louis ◽  
H. Favre
Keyword(s):  
Sodium Intake ◽  
Rat Kidney ◽  
Extracellular Volume ◽  
Gel Filtration ◽  
Kidney Tissue ◽  
Weight Fraction ◽  
Sodium Content ◽  
Sodium Balance ◽  
Low Molecular Weight ◽  
Extracellular Volume Expansion

1. The effect of the sodium content of the diet on the natriuretic activity of an extract from the kidneys was studied in non-expanded and volume-expanded rats. 2. The kidney tissue was homogenized and the supernatant fractionated by gel filtration on Sephadex G-25. A single low-molecular-weight fraction eluted after the salt possessed the natriuretic activity and was tested on a rat bioassay. 3. The natriuretic activity of the fraction obtained from the kidneys of non-expanded rats was related to the sodium intake. 4. After an acute extracellular volume expansion, the natriuretic activity obtained from the fraction extracted from the kidneys was much greater than before expansion and was related to the dietary intake of sodium.

Anti-Inflammatory Activity in the Low Molecular Weight Fraction of Commercial Human Serum Albumin (LMWF5A)

2015 ◽  
Vol 37 (1) ◽  
pp. 55-67 ◽  
Author(s):  
Gregory W. Thomas ◽  
Leonard T. Rael ◽  
Charles W. Mains ◽  
Denetta Slone ◽  
Matthew M. Carrick ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Weight Fraction ◽  
Inflammatory Activity ◽  
Low Molecular Weight ◽  
Anti Inflammatory

Characterization of Sol and Gel in Hevea Natural Rubber

1997 ◽  
Vol 70 (5) ◽  
pp. 707-713 ◽  
Author(s):  
Jitladda Tangpakdee ◽  
Yasukuki Tanaka
Keyword(s):  
Molecular Weight ◽  
Weight Fraction ◽  
Toluene Solution ◽  
Low Molecular Weight ◽  
Branch Points ◽  
Gel Content ◽  
High Ammonia ◽  
Linear Molecules ◽  
Cis And Trans

Abstract The gel content of rubber from high-ammonia latex (HA-latex) decreased significantly after deproteinization with proteolytic enzyme. The addition of 1–2% ethanol in toluene solution reduced the gel content of rubbers from HA-latex, deproteinized HA-latex (HA-DP) and pale crepe. Transesterification of the rubber in toluene solution with sodium methoxide dissolved the gel fraction. The gel fractions solubilized after transesterification showed molecular weight distribution rich in low molecular-weight fraction. The Huggins k′ constant of the fractionated rubbers from solubilized-gels was in the range of 0.42–0.45, lower than that of the fractionated HA-DP of 0.5–0.8. This indicates that all the branch-points were decomposed by transesterification to form linear molecules. The Mn values of rubber chains assembling the gel was 5.5−8.3×105 by 13C-NMR measurements of the ratio between cis- and trans-isoprene units, which were comparable to the molecular weight between crosslinks, Mc, of 7−11×105 by swelling measurements. These findings suggest that the branching and crosslinks are composed of two types of branch-points, i. e. one by association or aggregation of proteins or oligopeptides at the initiating end and the other by ester linkages including phosphoric ester at the terminal end.

scholarly journals Antitumor Activities of Low Molecular Weight Fraction Derived from the Cultured Fruit Body of Sparassis crispa in Tumor-Bearing Mice

2007 ◽  
Vol 54 (9) ◽  
pp. 419-423 ◽  
Author(s):  
Kyosuke Yamamoto ◽  
Yoshihiro Nishikawa ◽  
Takashi Kimura ◽  
Munehiko Dombo ◽  
Nariaki Matsuura ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Fruit Body ◽  
Weight Fraction ◽  
Low Molecular Weight ◽  
Antitumor Activities ◽  
Tumor Bearing ◽  
Sparassis Crispa
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