Incorporation of glucose by the sheep conceptus between days 13 and 19 of pregnancy

1989 ◽  
Vol 1 (2) ◽  
pp. 137 ◽  
Author(s):  
RG Wales ◽  
CL Cuneo ◽  
EE Waugh
Keyword(s):  
Culture Medium ◽  
Soluble Fraction ◽  
Embryonic Disc ◽  
Lactate And Pyruvate ◽  
Extraembryonic Membranes

Incorporation of glucose into the internal biochemical pools of the sheep embryo and samples of extraembryonic membranes was measured during a 2.5 h incubation in the presence of radiolabelled glucose. Very little glucose was incorporated into the glycogen pools by either the embryo or its membranes and never represented more than 5% of total incorporation. Approximately 65% of label was isolated in the non-glycogen acid-soluble fraction of samples and the remainder was incorporated into non-glycogen macromolecules. The embryonic disc of the day-13 conceptus had the highest rate of incorporation per mg dried weight of any structure studied. Synthesis of non-glycogen macromolecules by the day-13 disc was five to six times that of either day-15 or day-17 embryos. On day 19 very low rates of incorporation into the isolated embryo were found during culture. Evidence suggests that this was a result of limitations on the diffusion of substrate into the embryo because incubation of fragmented embryos produced rates similar to those found on days 15 and 17. Incorporation of glucose into the intracellular pools of extraembryonic membranes per mg dried weight remained relatively low and stable over the period studied and there were only minor differences in the rate of incorporation between membranes. Incorporation of glucose by embryos and extraembryonic membranes was equally as good in phosphate-buffered media as in bicarbonate-buffered solutions and was unaffected by changes in the concentration of lactate and pyruvate in the culture medium.

Characterization of protein production by caprine placental membranes: identification and immunolocalization of retinol-binding protein

1995 ◽  
Vol 146 (3) ◽  
pp. 527-534 ◽  
Author(s):  
K H Liu ◽  
J C Huang ◽  
J D Godkin
Keyword(s):  
Protein Production ◽  
Culture Medium ◽  
De Novo ◽  
Binding Protein ◽  
Yolk Sac ◽  
Retinol Binding Protein ◽  
Minimum Essential Medium ◽  
Placental Membranes ◽  
Extraembryonic Membranes

Abstract Caprine chorion, allantois and amnion from days 23, 28, 35, 39 and 45, and yolk sac from day 23 of pregnancy were isolated by dissection and cultured for 24 h in modified minimum essential medium in the presence of [35S] methionine. De novo-synthesized proteins released into the culture medium were analyzed by two-dimensional PAGE and fluorography. Patterns of protein production by these isolated extraembryonic membranes remained relatively unchanged from days 23 to 45 of pregnancy. Electrophoretic profiles of proteins synthesized by allantois and amnion were identical but distinct from that produced by chorion. Yolk sac was the major source of serum-like proteins. An acidic (pI 5·3–6·3) 22 kDa protein, which consisted of four isoelectric variants, was produced by all extraembryonic membranes and demonstrated to immunoreact with antiserum produced against bovine placental retinol-binding protein (RBP). Limited N-terminal sequence analysis of one major isoform indicated that the protein had complete homology with bovine RBP over the first 15 amino acids. Immunoreactive RBP was localized in epithelial cells lining the chorion, allantois and amnion. In this study, we have characterized and compared protein production by isolated extraembryonic membranes through days 23 to 45 of pregnancy and identified the 22 kDa protein as caprine RBP of placental origin. Journal of Endocrinology (1995) 146, 527–534

scholarly journals Metabolic studies in experimental liver disease resulting from d(+)-galactosamine administration

1972 ◽  
Vol 130 (1) ◽  
pp. 37-44 ◽  
Author(s):  
Christopher O. Record ◽  
K. G. M. M. Alberti ◽  
Dermot H. Williamson
Keyword(s):  
Phosphoenolpyruvate Carboxylase ◽  
Ketone Bodies ◽  
Soluble Fraction ◽  
Mass Action ◽  
Significant Elevation ◽  
Control Value ◽  
Glucose Synthesis ◽  
Lactate And Pyruvate ◽  
Experimental Liver ◽  
Pyruvate Ratio

1. In confirmation of previous work, administration of d(+)-galactosamine (0.5–0.75g/kg body wt.) to rats caused a hepatitis with histological evidence of liver damage and a 9-fold rise in aspartate aminotransferase activity in serum. 2. There was a significant elevation of blood lactate and pyruvate concentrations in 24h-starved rats treated with galactosamine but no change in the [lactate]/[pyruvate] ratio. 3-Hydroxybutyrate and acetoacetate concentrations in blood were decreased. 3. The changes in the concentrations of lactate, pyruvate and ketone bodies in the freeze-clamped liver were parallel to those observed in the blood. 4. In the livers of 24h-starved galactosamine-treated rats there were large increases in the concentrations of alanine (3-fold), citrate (5-fold), 2-oxoglutarate (4-fold), with smaller increases in malate, glutamate and aspartate. There was a 4-fold rise in the value of the mass-action ratio of the alanine aminotransferase system in the livers of galactosamine-treated rats when compared to controls. 5. There was a significant decrease in the activities of aspartate and alanine aminotransferases in the cytoplasm and the soluble fraction of sonicated homogenates of the livers of rats treated with galactosamine. The activity of phosphoenolpyruvate carboxylase was decreased by 75% of the control value. 6. Glucose synthesis from lactate in perfused livers from galactosamine-treated rats was inhibited 39% when compared with controls. 7. The results indicate that the conversion of lactate into glucose is decreased in the livers of galactosamine-treated rats and that this decrease may be due to the loss of phosphoenolpyruvate carboxylase from damaged hepatocytes.

Oxidation of

1993 ◽  
Vol 5 (2) ◽  
pp. 201 ◽  
Author(s):  
RG Wales ◽  
EE Waugh
Keyword(s):  
Yolk Sac ◽  
Metabolic Energy ◽  
Embryonic Tissue ◽  
Co2 Production ◽  
Acetate Metabolism ◽  
Embryonic Disc ◽  
Extraembryonic Membranes

Acetate metabolism by the sheep conceptus was assessed by measuring CO2 production during a 2.5-h incubation of embryos and samples of the extraembryonic membranes in HEPES-buffered media containing 1.12 mM [U-14C]acetate. The rate of oxidation of acetate by embryonic tissue showed little change between Days 13 and 15 of pregnancy but greatly decreased by Days 17 and 19. By contrast, oxidation of the substrate by the trophoblast increased substantially with development and was five times the early rate by Day 19. Oxidation of acetate by the yolk sac also increased 4-fold between Days 17 and 19. The addition of glucose to incubations of extraembryonic membranes resulted in some reduction in the oxidation of acetate by the yolk sac and allantois but had little effect on the trophoblast. At Days 13 and 15, the rate of oxidation of acetate by the embryonic disc was 6-7 times that by the trophoblast. As development progressed, this situation was reversed and by Day 19 the trophoblast metabolized more than five times the amount of acetate per microgram than did the Day-19 embryo. Although acetate metabolism by yolk sac and allantois on Day 17 was low, its metabolism by the yolk sac increased to values similar to those for the trophoblast at Day 19 but its utilization by the allantoic membrane remained low. Comparison of the estimates of ATP generated from acetate by these tissue with those published for glucose demonstrates that acetate is much less effective than glucose for the provision of metabolic energy.

Subcellular localization of PEPCK and metabolism of gluconeogenic substrains of renal cell lines

1995 ◽  
Vol 268 (2) ◽  
pp. C449-C457 ◽  
Author(s):  
T. Holcomb ◽  
N. P. Curthoys ◽  
G. Gstraunthaler
Keyword(s):  
Phosphoenolpyruvate Carboxykinase ◽  
Culture Medium ◽  
Northern Blot Analysis ◽  
Mitochondrial Marker ◽  
Activity Data ◽  
Cell Strains ◽  
Lactate And Pyruvate ◽  
Low Levels ◽  
Lactate Consumption ◽  
Renal Cell Lines

The two gluconeogenic substrains of renal epithelial cells, LLC-PK1-FBPase+ and OKGNG+, have been shown to differ markedly in their metabolism of lactate and pyruvate. OKGNG+ cells consumed lactate as well as pyruvate at high rates in contrast to LLC-PK1-FBPase+ cells, which failed to take up or utilize lactate. (Aminooxy)acetate (AOA), an inhibitor of transamination reactions, was used to further delineate these differences. Lactate consumption of OKGNG+ cells was significantly inhibited by AOA, whereas pyruvate consumption by LLC-PK1-FBPase+ cells was slightly stimulated. Growth of OKGNG+ cultures, however, could be achieved on lactate in the presence of AOA. From these results it was concluded that the cell strains might differ in the subcellular distribution of phosphoenolpyruvate carboxykinase (PEPCK). LLC-PK1-FBPase+ cells may express both mitochondrial and cytosolic PEPCK isoenzymes, whereas OKGNG+ cells express only the mitochondrial isoenzyme. This was tested by directly assaying PEPCK activity in subcellular fractions of the cells. In OKGNG+ cells PEPCK activity fractionated with the mitochondrial marker glutamate dehydrogenase; however, in LLC-PK1-FBPase+ cells two-thirds of PEPCK activity was found in the cytosol. In LLC-PK1-FBPase+ cells, PEPCK activity increased twofold on incubation in acidic culture medium (pH 6.9) for 18 h, in contrast to the PEPCK activity in OKGNG+ cells. Northern blot analysis using cDNA probes specific for the mitochondrial and cytosolic PEPCK mRNAs confirmed the enzyme activity data. In LLC-PK1-FBPase+ cells strong expression of cytosolic PEPCK mRNA was observed, whereas in OKGNG+ cells only very low levels could be detected.(ABSTRACT TRUNCATED AT 250 WORDS)

The release of membrane antigens into culture by adult Schistosoma mansoni

Parasitology ◽  
1975 ◽  
Vol 71 (2) ◽  
pp. 247-259 ◽  
Author(s):  
J. R. Kusel ◽  
P. E. Mackenzie ◽  
D. J. McLaren
Keyword(s):  
Schistosoma Mansoni ◽  
Culture Medium ◽  
Soluble Fraction ◽  
Culture Media ◽  
Surface Membrane ◽  
Microscope Examination ◽  
Particulate Form ◽  
Surface Labelling ◽  
Membrane Antigens ◽  
Solution Surface

Antigens sharing determinants with surface membranes and soluble proteins of adult Schistosoma mansoni have been detected in culture media after incubation of radioactively labelled worms. The relative quantities of these antigens were measured with specific antisera raised in rabbits and with serum from an immune rhesus monkey. It was found that 12–16% of TCA-precipitable radioactivity in the culture medium consisted of membrane antigens and 6–8% consisted of antigens sharing determinants with proteins found in the soluble fraction of adult worms. Over half the membrane antigens were present in particulate form, while other antigens were present in solution. Surface labelling the adult worms with [125I]confirmed that some of the particles in the culture medium were derived from the surface membrane of the adult worm and electron microscope examination of such particles showed that large membrane fragments were present. These results support the hypothesis that anti-bodies against schistosome membrane antigens are induced by particulate membrane antigens released by the parasite.

Effect of oxygen concentration on the incorporation of glucose by the sheep conceptus between days 13 and 19 of pregnancy

1993 ◽  
Vol 5 (3) ◽  
pp. 317
Author(s):  
ZF Du ◽  
RG Wales
Keyword(s):  
Oxygen Concentration ◽  
Soluble Fraction ◽  
Embryonic Tissue ◽  
Initial Value ◽  
Glucose Carbon ◽  
O2 Concentration ◽  
Glucose Incorporation ◽  
Extraembryonic Membranes ◽  
Effect Of Oxygen ◽  
Sole Energy

Embryos and extraembryonic membranes recovered from the sheep conceptus on Days 13, 15, 17 and 19 of pregnancy were incubated in medium containing glucose as sole energy substrate. In all components of the conceptus 60-70% of substrate carbon incorporated was recovered in the non-glycogen acid-soluble fraction, 25-30% in non-glycogen macromolecules and 4-8% in the glycogen pools. At all stages of development examined, embryonic tissue accumulated more glucose carbon into all fractions than did yolk sac which in turn was more active than trophoblast. After its appearance, the allantois was at least as active in glucose incorporation as embryonic tissue. Over the period of development examined, incorporation into all tissues of the conceptus fell progressively as pregnancy advanced and, by Day 19, total incorporation was about 60% of the initial value for each component. Reduction in oxygen concentration generally depressed incorporation into all intracellular carbon pools. The most consistent and significant effects were recorded for the two non-glycogen pools where incorporation fell, on average, by 30-40% when O2 concentration was reduced to 1%. Most of the response observed was due to a drop in O2 concentration from 20 to 5% with smaller additional effects when the O2 was further reduced to 1%. Incorporation into all pools isolated tended to follow a similar pattern and incorporation into the three macromolecular components, expressed as a percentage of total incorporation, remained unchanged as O2 concentration was reduced.

Influence of abscisic acid on the derepression of the acid phosphatases in Ipomoea sp. cultured in vitro

1983 ◽  
Vol 61 (9) ◽  
pp. 2343-2348
Author(s):  
M. W. Zink
Keyword(s):  
Abscisic Acid ◽  
Culture Medium ◽  
Soluble Fraction ◽  
Morning Glory ◽  
Acid Phosphatases ◽  
Developmental Patterns ◽  
Phosphate Deprivation ◽  
Mineral Stress ◽  
High Phosphate

The effect of abscisic acid on the levels and the developmental patterns of the two acid phosphatases in the culture medium, in the soluble fraction, and in the particulate fraction of Ipomoea sp. (morning glory) cultured in vitro depends upon the phosphate status of the cells. Under conditions of mineral stress or phosphate deprivation the enzymes are derepressed and this derepression is suppressed by abscisic acid. No inhibition of the synthesis of the phosphatases by the hormone occurs when the cells are grown under conditions of high phosphate. The significance of the abscisic effect on the derepression of the acid phosphatases is discussed.

Acid phosphatases of Ipomoea sp. cultured in vitro. 1. Influence of pH and inorganic phosphate on the formation of phosphatases

1979 ◽  
Vol 57 (7) ◽  
pp. 739-753 ◽  
Author(s):  
M. W. Zink ◽  
I. A. Veliky
Keyword(s):  
Inorganic Phosphate ◽  
Culture Medium ◽  
Soluble Fraction ◽  
Morning Glory ◽  
Acid Phosphatases ◽  
Developmental Patterns ◽  
Low Concentrations ◽  
Shake Flasks ◽  
Influence Of Ph

The levels and the developmental patterns of the two acid phosphatases in Ipomoea sp. (morning glory) were influenced by the pH of the medium and whether the cultures were grown in fermentors or shake flasks. The two enzymes, which appeared in the culture medium, in the soluble fraction, and in the particulate fraction, were derepressed when suspension cultures were grown in a medium containing low concentrations of inorganic phosphate. The addition of up to 4 μmol of phosphate per millilitre to cells grown for 4 days on low phosphate did not repress the synthesis of the enzymes. However, the addition of excess phosphate resulted in a temporary cessation of phosphatase synthesis. Inorganic phosphate appeared to be only one of several factors controlling the levels of the enzymes.

5. Mitt.: Über den Einfluß von Ethambutol auf den endogenen Stoffwechsel von M. smegmatis / The Endogenous Metabolism of Mycobacteria V: The Influence of Ethambutol on the Endogenous Metabolism of M. smegmatis

1972 ◽  
Vol 27 (11) ◽  
pp. 1405-1411 ◽  
Author(s):  
H. Reutgen ◽  
H. Iwainsky
Keyword(s):  
Main Part ◽  
Culture Medium ◽  
Specific Activity ◽  
Soluble Fraction ◽  
Endogenous Respiration ◽  
Phosphate Metabolism ◽  
Phosphate Content ◽  
Chronological Order ◽  
Endogenous Metabolism ◽  
Rna And Dna

1. Under conditions of the endogenous respiration the mode of action of ethambutol on mycobacteria was studied. Oxygen uptake, 32P-incorporation and changes in the phosphate-content were measured as parameters for the behaviour of the metabolism.2. In order to localize the first step of inhibition the radioactive isotope was applicated in a fixed chronological order and a fractionation in acid-soluble fraction, polyphosphate-, RNA- and DNA-fraction was carried out.3. Proportional to the incubation periode the 32P was incorporated into the acid-soluble fraction, into the polyphosphate- and into the RNA-fraction in about the same proportions. The content in the DNA-fraction is nearly 200-times lower than in the RNA-fraction.4. The main part of the phosphate is localized in the RNA (∼60%). Only in the begin of the incubation periode the part of the acid-soluble fraction is higher than that of the polyphosphate fraction.5. The main part of the phosphate, transferred from the culture medium into the bacteries, was found in the polyphosphate fraction. During the incubation periode the phosphate-content in the RNA-fraction remains nearly unchanged. After decreasing to the begin the same was found for the acid-soluble fraction.6. The specific activity of the polyphosphate fraction rises not continuously, according to the changes of the polyphosphate-content. Depending on the incubation periode the occured changes in the relations of the single fractions are similar in both the control- and the Ethambutol-trial.7. In contrary to the results of other authors these investigations showed the same degree of inhibition of the phosphate metabolism in the acidsoluble fraction, the polyphosphate and the RNA-fraction.8. Under conditions of the endogenous respiration ethambutol is inhibiting the phosphorylation of specific compounds of the intermediar-metabolism in the acid-soluble fraction or their further reactions. On the other side the changed incorporation of the 32P can be explained with a alterated permeability of the cell wall of the bacteria.

Sign in / Sign up

Export Citation Format

Share Document