The relationship between metallothionein and intestinal zinc absorption in the winter flounder

1984 ◽  
Vol 62 (11) ◽  
pp. 2211-2220 ◽  
Author(s):  
M. A. Shears ◽  
G. L. Fletcher
Keyword(s):  
Molecular Weight ◽  
Zinc Uptake ◽  
Winter Flounder ◽  
Zinc Binding ◽  
Low Molecular Weight ◽  
Zinc Absorption ◽  
Marine Teleost ◽  
Pseudopleuronectes Americanus ◽  
Chromatographic Techniques ◽  
The Relationship

Chromatographic techniques were used to investigate the presence of zinc-binding proteins in the intestinal mucosal cytosols of a marine teleost, the winter flounder (Pseudopleuronectes americanus). A low molecular weight, zinc-binding protein, characterized as metallothionein, was isolated from the intestinal cytosols of zinc-injected flounder. Metallothionein synthesis was induced in the intestine of the flounder by parenteral injections of zinc. However, studies conducted to assess the involvement of metallothionein in gastrointestinal zinc uptake indicated that its presence in the intestinal cytosol was not associated with any enhancement or depression of zinc uptake. These findings contrast with current hypotheses concerning metallothionein function in mammalian intestines.

Hepatic metallothionein in the winter flounder (Pseudopleuronectes americanus)

1985 ◽  
Vol 63 (7) ◽  
pp. 1602-1609 ◽  
Author(s):  
M. A. Shears ◽  
G. L. Fletcher
Keyword(s):  
Molecular Weight ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Acid Composition ◽  
Metal Binding ◽  
Winter Flounder ◽  
Low Molecular Weight ◽  
Pseudopleuronectes Americanus ◽  
Metal Binding Protein ◽  
Hepatic Metallothionein

A low molecular weight, metal-binding protein, characterized as metallothionein, was isolated from the liver cytosols of winter flounder injected with zinc or cadmium. This identity was confirmed by its amino acid composition, which was similar to that of metallothioneins isolated from the intestinal mucosal cytosol of zinc-injected flounder and from liver cytosols of other species of fish and mammals.

A proposed mechanism of zinc absorption in the rat

1975 ◽  
Vol 228 (2) ◽  
pp. 501-505 ◽  
Author(s):  
GW Evans ◽  
CI Grace ◽  
HJ Votava
Keyword(s):  
Molecular Weight ◽  
Bile Duct ◽  
Plasma Membranes ◽  
Basolateral Membrane ◽  
Serum Zinc ◽  
Zinc Binding ◽  
Whole Body ◽  
Low Molecular Weight ◽  
Zinc Absorption ◽  
Deficient Diet

Studies were conducted at the cellular level in an attempt to describe the processes involved in zinc absorption from the intestine. A low-molecular-weight zinc-binding ligand was identified in the pancreas of rats and pancreatic secretions from a dog. The whole-body absorption of 65Zn in rats in which the common bile duct was ligated was significantly less than the absorption of 65Zn in rats in which the hepatic bile duct was ligated. The uptake of 65Zn by epithelial cells from everted intestinal segments was markedly increased in the presence of the zinc-binding ligand fraction from pancreatic secretions. Following in vivo labeling, 30% of the 65Zn in the epithelial cell was associated with the partially purified basolateral plasma membrane. When labeled basolateral plasma membranes were incubated in a medium that contained zinc-free albumin, approximately 96% of the 65Zn was transferred to the medium while less than 30% of the isotope was released to media that contained either no albumin or a 3:1 zinc: albumin complex. In rats fed a zinc-deficient diet, 65Zn absorption was inversely proportional to the serum zinc concentration, and both zinc and copper injections produced a marked decrease in 65Zn absorption. These results suggest that zinc absorption consists of interactions among a low-molecular-weight ligand, recpetor sites on the basolateral membrane, and metal-free albumin.

Zinc- and copper-binding proteins in the plasma of winter flounder (Pseudopleuronectes americanus)

1980 ◽  
Vol 58 (4) ◽  
pp. 609-613 ◽  
Author(s):  
P. E. Fletcher ◽  
G. L. Fletcher
Keyword(s):  
Molecular Weight ◽  
Binding Proteins ◽  
Binding Protein ◽  
Gel Filtration ◽  
Protein S ◽  
Egg Yolk ◽  
Winter Flounder ◽  
Zinc Binding ◽  
Copper Binding ◽  
Copper Binding Proteins

Zinc- and copper-binding proteins were isolated from the plasma of winter flounder using gel filtration chromatography. A single copper-binding protein fraction of molecular weight 170 000 was isolated from the plasma of both sexes.In male and female flounder over 95% of the plasma zinc was associated with a zinc-binding protein(s) with a molecular weight of 76 000. In male flounder the remaining zinc appeared to be bound to a protein(s) of molecular weight 186 000. In female flounder the remaining 5% of the zinc was associated with two zinc-binding fractions with apparent molecular weights of 186 000 and 340 000 – 370 000.Extracts of plasma vitellogenin and egg yolk proteins revealed significant quantities of zinc and copper. It is hypothesized that the female specific zinc-binding protein (340 000 – 370 000) was vitellogenin.

Stress protein content of mature Brassica seeds and their germination performance

1998 ◽  
Vol 8 (3) ◽  
pp. 347-355 ◽  
Author(s):  
Mary Bettey ◽  
W. E. Finch-Savage
Keyword(s):  
Molecular Weight ◽  
Water Stress ◽  
Seed Development ◽  
Positive Relationship ◽  
Stress Proteins ◽  
Stress Protein ◽  
Low Molecular Weight ◽  
Optimal Conditions ◽  
Seed Vigour ◽  
The Relationship

AbstractPlants respond to sub-optimal conditions by the synthesis of specific ‘stress’ proteins, and these are thought to play a role in stress tolerance. Some of these proteins accumulate during late seed development, arguably to protect against damage during post-maturation drying and subsequent imbibition, prior to germination. Seed vigour is also determined during this late stage of seed development. High vigour seeds are those that can withstand the desiccation required for storage and successfully germinate under sub-optimal conditions to establish healthy seedlings. If stress proteins are involved in tolerating stress conditions, then they are likely to be important determinants of seed vigour. In this work the relationship between seed vigour (measured by seed germination performance following rapid aging, or under water stress) in Brassica oleracea var. capitata and the content of two classes of stress protein (dehydrins and a low molecular weight heat shock protein HSP17.6) at maturity was examined. Dehydrins did not show a positive relationship with seed performance. However, the protein HSP17.6 showed a positive correlation with seed performance, and a treatment that reduced the amount of this protein in the seed also caused a reduction in subsequent seed performance.

Absorption of trace metals in the zinc-deficient rat

1975 ◽  
Vol 228 (4) ◽  
pp. 1020-1023 ◽  
Author(s):  
CJ Hahn ◽  
GW Evans
Keyword(s):  
Molecular Weight ◽  
Trace Elements ◽  
Gel Filtration ◽  
Weight Fraction ◽  
Intestinal Content ◽  
Whole Body ◽  
Low Molecular Weight ◽  
Zinc Absorption ◽  
Body Absorption ◽  
Insight Into

The effects of zinc deficiency on the whole-body absorption and intestinal content of Zn, Cd, Cu, Co, Fe, Mn, and Cr were determined in the rat 1 h after oral administration of the isotopes. Both the absorption and intestinal content of Zn and Cr were increased in zinc-deficient rats, and the intestinal content of Feand Co was also increased in the zinc-deficient animals. Zinc administered orally with Cr decreased both absorption and intestinal content of the isotope in zinc-deficient rats. Chromium administered orally with Zn decreased intestinal content and absorption of Zn in zinc-deficient rats. Fractionation of mucosal supernatants by gel filtration showed that both zinc and chromium eluted in the same low molecular weight fraction. The elution patterns of zinc and cadmium from that of zinc-supplemented animals. These experiments provide some insight into the specificity of the zinc absorption pathway and present some explanations for the interaction or lack of interaction among trace elements.

The relationship between molecular weight and antifreeze polypeptide activity in marine fish

1986 ◽  
Vol 64 (3) ◽  
pp. 578-582 ◽  
Author(s):  
Ming H. Kao ◽  
Garth L. Fletcher ◽  
Nam C. Wang ◽  
Choy L. Hew
Keyword(s):  
Molecular Weight ◽  
Thermal Hysteresis ◽  
Freezing Temperature ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Molecular Weights ◽  
Shorthorn Sculpin ◽  
Myoxocephalus Scorpius ◽  
Antifreeze Peptides ◽  
Antifreeze Activity

Previous studies have established that the capacity of the glycopeptide antifreezes to depress the freezing temperature of aqueous solutions is positively correlated with molecular weight. The present study was carried out to determine whether a similar correlation existed within the antifreeze peptides. Two approaches were used. Initially, the antifreeze activity (thermal hysteresis) curves of antifreeze peptides from winter flounder, Pseudopleuronectes americanus (molecular weight, 3300), shorthorn sculpin, Myoxocephalus scorpius (molecular weight, 4000), ocean pout, Macrozoarces americanus (molecular weight, 6000), and sea raven, Hemitripterus americanus (molecular weight, 9700), were compared. In the second approach, a more specific comparison was made of two different sized antifreeze peptide components (molecular weights, 2900 and 4000) from the shorthorn sculpin. In both approaches, antifreeze peptide activity was positively correlated with molecular weight and the curve illustrating this relationship suggests that any reduction in molecular weight below 3300 will result in a disproportionate decline in activity. The relatively small antifreeze peptides from the winter flounder and shorthorn sculpin had greater activity than did glycopeptide antifreezes of similar size. However, glycopeptide antifreezes with a molecular weight of 10 000 or more had activities that exceeded that of any known antifreeze peptide. Increases in molecular weight of antifreeze peptides above 4000 resulted in a decline in antifreeze activity per milligram protein. Therefore, in terms of ability to depress the freezing temperature, there appears to be no advantage in evolving large antifreeze peptide molecules.

FRACTIONATION OF LIVER SOMATOMEDIN ACTIVITY BY ULTRAFILTRATION

1974 ◽  
Vol 62 (2) ◽  
pp. 355-361 ◽  
Author(s):  
JENNIFER M. DEHNEL ◽  
P. D. McCONAGHEY ◽  
M. J. O. FRANCIS
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Weight Fraction ◽  
Low Molecular Weight ◽  
High Molecular Weight Fraction ◽  
Cartilage Growth ◽  
The Relationship ◽  
Somatomedin Inhibitors

SUMMARY Plasma somatomedin is the intermediary through which growth hormone (GH) exerts its effects on the growing skeleton. Somatomedin activity may be produced in vitro by perfusion of the liver and kidneys of rats with Waymouth's medium containing GH. The relationship between the activity of plasma somatomedin and somatomedin of hepatic and renal origin has yet to be clarified. Somatomedin from plasma can be separated into active fractions of both high and low molecular weight. Similarly, ultrafiltration of medium containing somatomedin of hepatic origin indicates the existence of two active fractions, one of high molecular weight (greater than 50000) and one of low molecular weight (less than 1000). The latter can be attributed to the release of amino acids, such as serine and glutamine, by the perfused tissue. The high molecular weight fraction is believed to represent GH-dependent somatomedin. Fractions that inhibit production of cartilage matrix are present in liver perfusates as well as in plasma. These results provide further evidence that the liver is a source of GH-dependent somatomedin in vivo. Furthermore, cartilage growth may be controlled not only by the GH-stimulated release of somatomedin by the liver, but also by its release of acid-labile somatomedin inhibitors.

Heterogeneity of antifreeze polypeptides from the Newfoundland winter flounder, Pseudopleuronectes americanus

1984 ◽  
Vol 62 (1) ◽  
pp. 28-33 ◽  
Author(s):  
Ron M. Fourney ◽  
Shashikant B. Joshi ◽  
Ming H. Kao ◽  
Choy L. Hew
Keyword(s):  
Molecular Weight ◽  
High Performance Liquid Chromatography ◽  
Gel Electrophoresis ◽  
High Performance ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Winter Flounder ◽  
Pseudopleuronectes Americanus ◽  
Reverse Phase ◽  
Antifreeze Polypeptides

The heterogeneity of Newfoundland winter flounder antifreeze polypeptides was analyzed by reverse phase high performance liquid chromatography and by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Seven antifreeze polypeptide components could be readily demonstrated. Five of the components were similar in molecular weight (3300) and amino acid composition. Two of the antifreeze polypeptide components were larger (4500) and contained valine. The two major components (components 6 and 8) were identical to those reported earlier from our laboratories.

A low molecular weight peptide from snow mold with epitopic homology to the winter flounder antifreeze protein

1994 ◽  
Vol 72 (3-4) ◽  
pp. 152-156 ◽  
Author(s):  
W. Jay Newsted ◽  
Sandra Polvi ◽  
Bob Papish ◽  
Ed Kendall ◽  
Mohammed Saleem ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Antifreeze Protein ◽  
Cross Reactivity ◽  
Winter Flounder ◽  
Low Molecular Weight ◽  
Culture Temperature ◽  
Snow Mold ◽  
Typhula Incarnata ◽  
Magnetic Resonance Microimaging ◽  
Nuclear Magnetic Resonance Microimaging

Evidence for a small size protein (ca. 3500 kDa) exhibiting epitopic homology to the Atlantic winter flounder antifreeze protein (AFP) is found in the snow molds Coprinus psychromorbidus, Myriosclerotinia borealis, and Typhula incarnata. The protein shows strong cross-reactivity with antisera specific for the flounder AFP. Preliminary studies suggest that the protein is synthesized in response to lowering the culture temperature, and that it is membrane associated and, therefore, may function in an analogous capacity to the fish AFP. Also, the protein is shown to have antifreeze properties as determined by nuclear magnetic resonance microimaging experiments.Key words: antifreeze proteins, low temperature stress, snow mold, winter flounder.

Biological activity of 2,4-D esters on rubber vine (Cryptostegia grandiflora): dependence on vapour pressure and molecular weight and isomerism of the alcohol substituent

1989 ◽  
Vol 40 (3) ◽  
pp. 685
Author(s):  
GJ Harvey
Keyword(s):  
Molecular Weight ◽  
Vapour Pressure ◽  
Low Molecular Weight ◽  
Straight Chain ◽  
Biological Efficacy ◽  
Cryptostegia Grandiflora ◽  
Normal Series ◽  
Branched Chain ◽  
The Relationship ◽  
Volatile Esters

The relationship between molecular structure and biological efficacy was investigated for 16 esters of 2,4-D [(2,4-dich1orophenoxy)acetic acid] on rubber vine (Cryptostegia grandiflora). These included the normal (n) or straight-chain esters from C-1 (methyl) to C-8 (octyl), the n-decyl, n-dodecyl, isobutyl, amyl (iso-pentyl), 2-ethylhexyl (iso-octyl), and the methoxy-, ethoxy-, and butoxyethyl esters. For the normal series esters, biological efficacy was found to be a function of both the molecular weight and the vapour pressure of the esters. This relationship was linear for the higher molecular weight, low volatile esters, biological efficacy decreasing with increasing molecular weight and the accompanying decrease in vapour pressure of the esters. The low molecular weight, volatile esters were more active than the higher molecular weight, low volatile esters, and increases in the vapour pressure of these low molecular weight, volatile esters were sufficient to account for the deviation from linearity of those esters. When all esters are considered, the same relationships hold but the branched-chain (iso) and chemically substituted (alkoxy alcohol) esters are less effective than the corresponding normal esters. Possible reasons for these results are discussed.

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