Levels of Stable Zn and 65Zn in Crassostrea virginica from North Carolina

1970 ◽  
Vol 27 (1) ◽  
pp. 47-57 ◽  
Author(s):  
Douglas A. Wolfe
Keyword(s):  
North Carolina ◽  
Crassostrea Virginica ◽  
Half Life ◽  
Specific Activity ◽  
Adductor Muscle ◽  
Animal Tissues ◽  
Wet Weight ◽  
Zinc Levels

The concentration of zinc in oysters was highly variable — samples from relatively unpolluted estuaries of North Carolina contained, on the average, 85–245 ppm zinc, based on wet weight. Internal tissues, like adductor muscle and pericardial sac, had zinc levels less than half those of external tissues but zinc was nonetheless distributed uniformly throughout the animal tissues. During 1964–66, North Carolina oysters contained 2–20 pCi 65Zn from fallout per 100 g wet weight. Specific activity of 65Zn in these oysters during 1965–66 was in the range 90–300 pCi/g Zn, and was declining with an apparent half-life of 276 days.

Cadmium Uptake by Marine Organisms

1972 ◽  
Vol 29 (9) ◽  
pp. 1367-1369 ◽  
Author(s):  
R. Eisler ◽  
G. E. Zaroogian ◽  
R. J. Hennekey
Keyword(s):  
Crassostrea Virginica ◽  
Fundulus Heteroclitus ◽  
Sea Water ◽  
Homarus Americanus ◽  
Adductor Muscle ◽  
Marine Organisms ◽  
Cadmium Uptake ◽  
Wet Weight

Adults of mummichog, Fundulus heteroclitus, scallop Aquipecten irradians, oyster Crassostrea virginica, and subadult lobsters Homarus americanus were immersed for 21 days in flowing sea water containing 10 μg/liter of cadmium as[Formula: see text]. Cadmium residues in whole animals and selected tissues were consistently higher in exposed organisms than controls; edible portions of treated lobster (muscle), scallop (adductor muscle), and oyster (whole animal) contained more cadmium per unit wet weight than controls by 25%, 19%, and 352%, respectively.

Oyster citrate synthase: control of carbon entry into the Krebs cycle of a facultative anaerobe

1976 ◽  
Vol 54 (6) ◽  
pp. 892-895 ◽  
Author(s):  
J. H. A. Fields ◽  
P. W. Hochachka
Keyword(s):  
Enzyme Activity ◽  
Catalytic Activity ◽  
Crassostrea Gigas ◽  
Citrate Synthase ◽  
Specific Activity ◽  
Krebs Cycle ◽  
Adductor Muscle ◽  
Facultative Anaerobe ◽  
Wet Weight ◽  
Regulatory Properties

Citrate synthase (EC 4.1.3.7) in adductor muscle of the oyster, Crassostrea gigas, occurred in relatively low specific activity, about 1.5 μmol product formed per minute per gram wet weight of tissue. The enzyme activity was essentially independent of pH between pH 7.5 and 9.0. The Km values for acetyl-CoA and oxaloacetate were about 0.005 mM in each case. Catalytic activity was modulated by the adenylates, citrate, and 2-ketoglutarate, all of which were inhibitory. The regulatory properties of the enzyme suggest that during the transition to anoxia oxaloacetate becomes limiting, thus reducing flux through the initial stages of the Krebs cycle.

Simultaneous optimization of activity and stability of xylose reductase from D. nepalensis NCYC 3413 using statistical experimental design

2020 ◽  
Vol 27 ◽  
Author(s):  
Shwethashree Malla ◽  
Sathyanarayana N. Gummadi
Keyword(s):  
Half Life ◽  
Specific Activity ◽  
Enzyme Stability ◽  
Reductase Activity ◽  
Xylose Reductase ◽  
Life Time ◽  
Economic Feasibility ◽  
Simultaneous Optimization ◽  
Physical Parameters ◽  
Statistical Experimental Design

Background: Physical parameters like pH and temperature play a major role in the design of an industrial enzymatic process. Enzyme stability and activity are greatly influenced by these parameters; hence optimization and control of these parameters becomes a key point in determining the economic feasibility of the process. Objective: This study was taken up with the objective to optimize physical parameters for maximum stability and activity of xylose reductase from D. nepalensis NCYC 3413 through separate and simultaneous optimization studies and comparison thereof. Method: Effects of pH and temperature on the activity and stability of xylose reductase from Debaryomyces nepalensis NCYC 3413 were investigated by enzyme assays and independent variables were optimised using surface response methodology. Enzyme activity and stability were optimised separately and concurrently to decipher the appropriate conditions. Results: Optimized conditions of pH and temperature for xylose reductase activity were determined to be 7.1 and 27 ℃ respectively, with predicted responses of specific activity (72.3 U/mg) and half-life time (566 min). The experimental values (specific activity 50.2 U/mg, half-life time 818 min) were on par with predicted values indicating the significance of the model. Conclusion: Simultaneous optimization of xylose reductase activity and stability using statistical methods is effective as compared to optimisation of the parameters separately.

Posttranslational modifications of recombinant myotube-synthesized human factor IX

Blood ◽  
2001 ◽  
Vol 97 (1) ◽  
pp. 130-138 ◽  
Author(s):  
Valder R. Arruda ◽  
James N. Hagstrom ◽  
Jeffrey Deitch ◽  
Terry Heiman-Patterson ◽  
Rodney M. Camire ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Posttranslational Modifications ◽  
Half Life ◽  
Specific Activity ◽  
Factor Ix ◽  
Serine Phosphorylation ◽  
Hemophilia B ◽  
Tyrosine Sulfation ◽  
Aav Vector ◽  
Carbohydrate Analysis

Abstract Recent data demonstrate that the introduction into skeletal muscle of an adeno-associated viral (AAV) vector expressing blood coagulation factor IX (F.IX) can result in long-term expression of the transgene product and amelioration of the bleeding diathesis in animals with hemophilia B. These data suggest that biologically active F.IX can be synthesized in skeletal muscle. Factor IX undergoes extensive posttranslational modifications in the liver, the normal site of synthesis. In addition to affecting specific activity, these posttranslational modifications can also affect recovery, half-life in the circulation, and the immunogenicity of the protein. Before initiating a human trial of an AAV-mediated, muscle-directed approach for treating hemophilia B, a detailed biochemical analysis of F.IX synthesized in skeletal muscle was carried out. As a model system, human myotubes transduced with an AAV vector expressing F.IX was used. F.IX was purified from conditioned medium using a novel strategy designed to purify material representative of all species of rF.IX in the medium. Purified F.IX was analyzed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE), N-terminal sequence analysis, chemical γ-carboxyglutamyl analysis, carbohydrate analysis, assays for tyrosine sulfation, and serine phosphorylation, and for specific activity. Results show that myotube-synthesized F.IX has specific activity similar to that of liver-synthesized F.IX. Posttranslational modifications critical for specific activity, including removal of the signal sequence and propeptide, and γ-carboxylation of the N-terminal glutamic acid residues, are also similar, but carbohydrate analysis and assessment of tyrosine sulfation and serine phosphorylation disclose differences. In vivo experiments in mice showed that these differences affect recovery but not half-life of muscle-synthesized F.IX.

THE GROSS AND MICROSCOPIC ANATOMY OF THE DIGESTIVE TRACT OF THE OYSTER CRASSOSTREA VIRGINICA (GMELIN)

1957 ◽  
Vol 35 (3) ◽  
pp. 325-347 ◽  
Author(s):  
Barbara L. Shaw ◽  
Helen I. Battle
Keyword(s):  
Epithelial Cells ◽  
Digestive Tract ◽  
Crassostrea Virginica ◽  
Atlantic Coast ◽  
Dorsal Surface ◽  
Adductor Muscle ◽  
Posterior Chamber ◽  
Microscopic Anatomy ◽  
The North ◽  
Cytoplasmic Processes

The gross and microscopic anatomy of the digestive tract of Crassostrea virginica (Gmelin), the common oyster of commerce of the North Atlantic Coast, is described. The dorsoventrally compressed mouth bounded by two pairs of labial palps leads into a crescentic oesophagus, thence to the anterior chamber of the stomach from which a complex caecum extends into anteriorly and posteriorly directed spiral appendices. The posterior chamber of the stomach bears a chondroid gastric shield and leads into an elongated chamber which is incompletely divided by two typhlosoles into a style-sac and mid-gut. The intestine is divisible into ascending, median, and descending limbs, the latter merging into the rectum which terminates on the dorsal surface of the adductor muscle. Extensively branched tubular digestive diverticula exit from the stomach by a series of ducts along the margin of the caecum and the posterior stomach. The complete digestive tract is lined by a simple columnar epithelium which is ciliated throughout with the exception of the upper lip or fused external palps, the lower side of the gastric shield in the posterior stomach, and the tubules of the digestive diverticula. Mucous secreting and eosinophilic epithelial cells occur in varying numbers along the course of the tract. Phagocytes are present between the lining epithelial cells, among the peripheral collagenous and muscle fibers, as well as in the lumen of the tract. The gastric shield is shown to be intimately attached to the underlying epithelium by a central clip as well as by minute cytoplasmic processes. The anatomical relationships are compared with various lamellibranchs including the Chilean oyster, Ostrea chilensis Philippi; the European oyster, Ostrea edulis L.; and the Portuguese oyster, Gryphea angulata Lamarck.

scholarly journals In Vitro Characterization of Rabbit Thrombin, Antithrombin III, and Thrombin-Antithrombin III Complex, and Determination of Their Survival Times in Vivo

1977 ◽  
Author(s):  
Christine N. Vogel ◽  
Kingdon S. Henry ◽  
Roger L. Lundblad
Keyword(s):  
Gel Electrophoresis ◽  
Half Life ◽  
Antithrombin Iii ◽  
Specific Activity ◽  
Sodium Dodecyl ◽  
In Vivo Studies ◽  
Survival Times ◽  
At Iii

Our intention is to study the interaction of rabbit thrombin with antithrombin III (AT-III) in vitro and in vivo. After activation of crude prothrombin with tissue thromboplastin and CaCl2, thrombin was purified and showed two species of thrombin with molecular weights of 36,000 and 39,000 daltons as determined by sodium dodecyl sulfate discontinuous gel electrophoresis. Rabbit AT-III was purified using a heparin agarose column and had a molecular weight of 55,000 daltons. The inhibition of thrombin by AT-III was followed by fibrinogen clotting assays and an AT-III-thrombin complex was observed on gel electrophoresis. For the in vivo studies both thrombin and AT-III were radiolabelled with Na125i using the solid state lactoperoxidase method and retained 99% of the pre-iodinated specific activity. Radiolabelled thrombin and a radiolabelled AT-III-thrombin complex were injected into different rabbits. The rate of removal of both was very similar with a half-life of approximately 9 hours. When radiolabelled AT-III was injected, the half-life was approximately 60 hours. Since the disappearance rate of thrombin more closely approximates that of the preformed AT-III-thrombin complex and is clearly shorter than the turnover rate of AT-III, the possibility is raised that thrombin combines in vivo with a native inhibitor such as AT-III and may in fact be removed from the circulation as a complex rather than as a native molecule.

Use of purified lyophilized human lactate dehydrogenase isoenzyme 5 in a study of measuring lactate dehydrogenase activity.

1989 ◽  
Vol 35 (8) ◽  
pp. 1774-1776 ◽  
Author(s):  
D A Smith ◽  
G C Moses ◽  
A R Henderson
Keyword(s):  
Lactate Dehydrogenase ◽  
Half Life ◽  
Specific Activity ◽  
Lactate Dehydrogenase Activity ◽  
Bovine Albumin ◽  
First Order ◽  
First Order Kinetics ◽  
The Stability ◽  
Lactate Dehydrogenase Isoenzymes ◽  
Excellent Stability

Abstract We examined the stability of human lactate dehydrogenase (EC 1.1.1.27) isoenzyme 5--purified to a specific activity of about 400 kU/g--when lyophilized in a buffered, stabilized matrix of bovine albumin. This isoenzyme was prepared with a final activity of about 500 U/L and stored at -20, 4, 20, 37, and 56 degrees C for as long as six months. This isoenzyme decayed with approximate first-order kinetics, with an estimated half-life at -20 degrees C of about 475 years. Stability of reconstituted samples stored at 20 or 4 degrees C was poor, suggesting that the reconstituted material should be used without delay; material stored at -20 degrees C showed excellent stability for 15 days. We propose that such preparations might be further investigated as standards for use in electrophoresis of lactate dehydrogenase isoenzymes.

scholarly journals Dating of Polar Ice By 32Si

1973 ◽  
Vol 12 (66) ◽  
pp. 411-416 ◽  
Author(s):  
Henrik B. Clausen
Keyword(s):  
Half Life ◽  
Specific Activity ◽  
Greenland Ice Sheet ◽  
Cosmic Ray ◽  
Polar Ice ◽  
Poor Knowledge ◽  
The Poor ◽  
Glacier Ice ◽  
Cosmic Ray Flux

32Si dating of glacier ice has hitherto been complicated by the poor knowledge of the half life. Furthermore, fall-out of bomb-produced 32Si impedes the determination of the specific activity of cosmic-ray produced 32Si in recent precipitation. Measurements on well-dated pre-bomb samples from the Greenland ice sheet establish a calibration for 32Si dating of up to 1 000 year old polar ice samples of the magnitude of 1 metric ton. If the technique is used on temperate glaciers, samples of pre-bomb deposits (or from after 1970) must be collected for comparison with samples of old ice, using an apparent half life of 295±25 years. Due to secular cosmic-ray flux variations, the true half life of 32Si is estimated at the slightly higher value of 330±40 years.

Determination of the specific ?-activity and the half-life of U233

Atomic Energy ◽  
1960 ◽  
Vol 6 (1) ◽  
pp. 41-41
Author(s):  
Ya. P. Dokuchaev ◽  
I. S. Osipov
Keyword(s):  
Half Life ◽  
Specific Activity

Half-Life Determination of 41Ca and Some Other Radioisotopes

Radiocarbon ◽  
1992 ◽  
Vol 34 (3) ◽  
pp. 436-446 ◽  
Author(s):  
Walter Kutschera ◽  
Irshad Ahmad ◽  
Michael Paul
Keyword(s):  
Mass Spectrometry ◽  
Electron Capture ◽  
Half Life ◽  
Specific Activity ◽  
Low Energy ◽  
X Rays ◽  
Weighted Mean ◽  
Electron Capture Decay

We have performed a new determination of the half-life of 41Ca by measuring the specific activity of an enriched Ca material with known 41Ca abundance. We measured the activity via the 3.3-keV X-rays emitted in the electron capture decay of 41Ca, and the 41Ca abundance was measured by low-energy mass spectrometry. The result, t1/2 = (1.01 ± 0.10) × 105 yr, agrees with the recent ‘geological’ half-life of Klein et al., (1991), t1/2 = (1.03 ± 0.07) × 105 yr, and with the corrected value of Mabuchi et al. (1974), t1/2 = (1.13 ± 0.12) × 105 yr. We recommend the weighted mean of these three measurements, t1/2 = (1.04 ± 0.05) × 105 yr, as the most probable half-life of 41Ca. We also discuss the situation of the radioisotopes, 32Si, 44Ti, 79Se and 126Sn, whose half-lives, though still uncertain, are potentially interesting for future AMS studies and other applications.

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