scholarly journals Changes in the expression of alpha-fodrin during embryonic development of Xenopus laevis.

1987 ◽  
Vol 105 (2) ◽  
pp. 843-853 ◽  
Author(s):  
D H Giebelhaus ◽  
B D Zelus ◽  
S K Henchman ◽  
R T Moon
Keyword(s):  
Steady State ◽  
Embryonic Development ◽  
Xenopus Laevis ◽  
De Novo ◽  
Single Gene ◽  
Predicted Amino Acid Sequence ◽  
Cdna Clones ◽  
De Novo Synthesis ◽  
S1 Nuclease ◽  
Stage Of Development

Fodrin (nonerythroid spectrin) and its associated proteins have been previously implicated in the establishment of specialized membrane-cytoskeletal domains in differentiating cells. Using antiserum which is monospecific for the alpha-subunit of fodrin, we demonstrate that alpha-fodrin is present in oocytes and adult tissues of Xenopus laevis. Analyses of the de novo synthesis of alpha-fodrin during embryonic development reveal that alpha-fodrin is synthesized in oocytes, but not during early development. To investigate the level of control of alpha-fodrin expression, we isolated two cDNA clones for oocyte alpha-fodrin. The oocyte cDNA clones were identified as encoding portions of alpha-fodrin based on DNA sequence analysis and on the comparison of the predicted amino acid sequence of the cDNAs with the known sequence of human erythrocyte alpha-spectrin. The Xenopus alpha-fodrin cDNAs hybridize to a transcript of approximately 9 kb on RNA blots, and probably to a single gene type on genomic DNA blots. Both RNA blot analyses and S1 nuclease protection assays with the Xenopus alpha-fodrin cDNAs demonstrate that the observed decline in the de novo synthesis of alpha-fodrin polypeptides is controlled by a dramatic decrease in the abundance of alpha-fodrin transcripts after fertilization. In contrast, levels of actin transcripts do not decrease during this period. Inasmuch as steady-state levels of alpha-fodrin transcripts rise by the neurula stage of development, these results suggest that the synthesis of alpha-fodrin polypeptides during embryonic development of Xenopus is regulated, rather than constitutive, and that the primary level of control is the steady-state abundance of mRNA.

Divergent effects of intravenous GSH and cysteine on renal and hepatic GSH

1992 ◽  
Vol 263 (2) ◽  
pp. R348-R352 ◽  
Author(s):  
S. Aebi ◽  
B. H. Lauterburg
Keyword(s):  
Steady State ◽  
De Novo ◽  
Feedback Inhibition ◽  
Therapeutic Use ◽  
Steady State Concentration ◽  
De Novo Synthesis ◽  
State Concentration ◽  
Cellular Thiol

There is a growing interest in the therapeutic use of sulfhydryls. To assess the effect of glutathione (GSH) and cysteine on the cellular thiol status, thiols were administered intravenously to rats in doses ranging from 1.67 to 8.35 mmol/kg with and without pretreatment with 4 mmol/kg buthionine-[S,R]-sulfoximine (BSO), an inhibitor of GSH synthesis. One hour after administration of 1.67 mmol/kg GSH, the concentration of GSH rose from 5.2 +/- 1.0 to 8.4 +/- 0.9 mumol/g and from 2.5 +/- 0.5 to 3.7 +/- 0.7 mumol/g in liver and kidneys, respectively. After 8.35 mmol/kg, hepatic GSH did not increase further, but renal GSH rose to 6.7 +/- 1.8 mumol/g. Infusion of cysteine increased hepatic GSH to the same extent as intravenous GSH, but renal GSH did not increase after 1.67 mmol/kg and even significantly decreased to 0.6 +/- 0.2 mumol/g after 8.35 mmol/kg. In the presence of BSO, GSH resulted in a significant increase in renal but not hepatic GSH, suggesting that the kidneys take up intact GSH and indicating that the increment in hepatic GSH was due to de novo synthesis. The present data show that hepatic GSH can be markedly increased in vivo by increasing the supply of cysteine. Measurements of hepatic cysteine indicate that up to a concentration of approximately 0.5 mumol/g cysteine is a key determinant of hepatic GSH, such that the physiological steady-state concentration of GSH in the liver appears to be mainly determined by the availability of cysteine. At higher concentrations GSH does not increase further, possibly due to feedback inhibition of GSH synthesis or increased efflux.(ABSTRACT TRUNCATED AT 250 WORDS)

Expression of intermediate filament proteins during development of Xenopus laevis. I. cDNA clones encoding different forms of vimentin

Development ◽  
1989 ◽  
Vol 105 (2) ◽  
pp. 279-298
Author(s):  
H. Herrmann ◽  
B. Fouquet ◽  
W.W. Franke
Keyword(s):  
Amino Acid ◽  
Xenopus Laevis ◽  
Intermediate Filament ◽  
De Novo ◽  
Mesenchymal Cell ◽  
Amino Acid Sequences ◽  
Cytoskeletal Proteins ◽  
Cdna Clones ◽  
Mammalian Development ◽  
Intermediate Filament Proteins

To provide a basis for studies of the expression of genes encoding the diverse kinds of intermediate-filament (IF) proteins during embryogenesis of Xenopus laevis we have isolated and characterized IF protein cDNA clones. Here we report the identification of two types of Xenopus vimentin, Vim1 and Vim4, with their complete amino acid sequences as deduced from the cloned cDNAs, both of which are expressed during early embryogenesis. In addition, we have obtained two further vimentin cDNAs (Vim2 and 3) which are sequence variants of closely related Vim1. The high evolutionary conservation of the amino acid sequences (Vim1: 458 residues; Mr approximately 52,800; Vim4: 463 residues; Mr approximately 53,500) to avian and mammalian vimentin and, to a lesser degree, to desmin from the same and higher vertebrate species, is emphasized, including conserved oligopeptide motifs in their head domains. Using these cDNAs in RNA blot and ribonuclease protection assays of various embryonic stages, we observed a dramatic increase of vimentin RNA at stage 14, in agreement with immunocytochemical results obtained with antibody VIM-3B4. The significance of very weak mRNA signals detected in earlier stages is discussed in relation to negative immunocytochemical results obtained in these stages. The first appearance of vimentin has been localized to a distinct mesenchymal cell layer underlying the neural plate or tube, respectively. The results are discussed in relation to programs of de novo synthesis of other cytoskeletal proteins in amphibian and mammalian development.

Lipid composition of developing Xenopus laevis embryos

1976 ◽  
Vol 54 (6) ◽  
pp. 578-582 ◽  
Author(s):  
Mary Mes-Hartree ◽  
John B. Armstrong
Keyword(s):  
Fatty Acids ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Xenopus Laevis ◽  
Lipid Content ◽  
Lipid Composition ◽  
De Novo ◽  
Total Lipid Content ◽  
De Novo Synthesis ◽  
Xenopus Laevis Embryos

The total lipid content, amount of phospholipid, proportions of major polar and neutral lipid classes, and the overall fatty acid composition were examined in Xenopus laevis embryos. No obvious differences were observed in any of the parameters between fertilization and hatching, or between eggs produced by different females. The average lipid content per egg was 113 μg, 31.6 μg of which was phospholipid. The major phospholipids were phosphatidylcholine and sphingomyelin. The major fatty acids were palmitic and oleic acids, but polyunsaturated fatty acids were also present in substantial amounts. The results suggest that significant de novo synthesis of lipids does not occur until after hatching.

scholarly journals Arabidopsis REI-LIKE proteins activate ribosome biogenesis during cold acclimation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bo Eng Cheong ◽  
Olga Beine-Golovchuk ◽  
Michal Gorka ◽  
William Wing Ho Ho ◽  
Federico Martinez-Seidel ◽  
...  
Keyword(s):  
Steady State ◽  
Feedback Control ◽  
Cold Acclimation ◽  
Ribosomal Proteins ◽  
Ribosome Biogenesis ◽  
Transcriptional Control ◽  
De Novo ◽  
De Novo Synthesis ◽  
Steady State Temperature

AbstractArabidopsis REIL proteins are cytosolic ribosomal 60S-biogenesis factors. After shift to 10 °C, reil mutants deplete and slowly replenish non-translating eukaryotic ribosome complexes of root tissue, while controlling the balance of non-translating 40S- and 60S-subunits. Reil mutations respond by hyper-accumulation of non-translating subunits at steady-state temperature; after cold-shift, a KCl-sensitive 80S sub-fraction remains depleted. We infer that Arabidopsis may buffer fluctuating translation by pre-existing non-translating ribosomes before de novo synthesis meets temperature-induced demands. Reil1 reil2 double mutants accumulate 43S-preinitiation and pre-60S-maturation complexes and alter paralog composition of ribosomal proteins in non-translating complexes. With few exceptions, e.g. RPL3B and RPL24C, these changes are not under transcriptional control. Our study suggests requirement of de novo synthesis of eukaryotic ribosomes for long-term cold acclimation, feedback control of NUC2 and eIF3C2 transcription and links new proteins, AT1G03250, AT5G60530, to plant ribosome biogenesis. We propose that Arabidopsis requires biosynthesis of specialized ribosomes for cold acclimation.

Accumulation of Proline and Sucrose during the First Hours after Transfer of Chlorella emevsonii to High NaCl

1979 ◽  
Vol 6 (1) ◽  
pp. 69 ◽  
Author(s):  
H Greenway ◽  
T.L Setter
Keyword(s):  
Steady State ◽  
Osmotic Potential ◽  
De Novo ◽  
Lag Phase ◽  
Sucrose Synthesis ◽  
De Novo Synthesis ◽  
Subsequent Period ◽  
Osmotic Solutes ◽  
Steady State Levels ◽  
Osmotic Solute

Net synthesis of proline, the main osmotic solute in C. emersonii, showed a lag of at least 15 min following transfer of cells from 1 m~ NaCl to concentrations ranging between 25 and 335 m~ NaCl. During the subsequent period of rapid net proline synthesis, the maximum rates were approximately linearly related to the decreases in external osmotic potential (YJ until the cells plasmolysed. Beyond the point of incipient plasmolysis, further large decreases in Y* did not change the maximum rates of proline synthesis. The steady-state levels of proline were lower, and were reached faster, the smaller the decreases in external Ys. Overall these results support the notion that turgor potential has a regulating role in the synthesis of osmotic solutes. Sucrose synthesis showed no lag and was rapid even in plasmolysed cells. Cycloheximide inhibited formation of proline but not of sucrose. This, together with the lag phase of 15 min in proline synthesis, indicated that transfer of C. emersonii to high NaCl induced de novo synthesis of enzymes involved in proline formation. Effects of DCMU and darkness were also measured. Cells transferred to 125 m~ NaCl still showed substantial net synthesis of sucrose, but not of proline. Supply of glucose in the dark did not lead to proline formation, but it did stimulate proline synthesis which occurred when glutamate was supplied.

scholarly journals Effects of meal ingestion on intramyocellular ceramide concentrations and fractional de novo synthesis in humans

2018 ◽  
Vol 314 (2) ◽  
pp. E105-E114 ◽  
Author(s):  
Jin Ook Chung ◽  
Christina Koutsari ◽  
Agnieszka Urszula Blachnio-Zablieska ◽  
Kazanna C. Hames ◽  
Michael D. Jensen
Keyword(s):  
Insulin Resistance ◽  
Steady State ◽  
De Novo ◽  
De Novo Synthesis ◽  
Overweight Status ◽  
Fractional Contribution ◽  
Meal Ingestion ◽  
Muscle Biopsies

We investigated the effects of meal ingestion on intramyofibrillar (IMF) and subsarcolemmal (SS) ceramide metabolism in volunteers ranging from lean to obese. Thirty-eight women and men underwent a steady-state meal ingestion protocol that included a 6.5-h infusion of [U-13C]palmitate and muscle biopsies 1.5 and 6.5 h after starting the tracer infusion. We measured IMF and SS sphingolipid concentrations and the contribution of plasma palmitate to intramyocellular C16:0 ceramide by use of LC-MS-MS. In response to meal ingestion SS C24 ceramide concentrations, but not C14-C20 concentrations, increased significantly. IMF ceramide concentrations did not change. The increases in SS C24 ceramides were negatively related to parameters of insulin resistance. The fractional contribution of plasma palmitate to intramyocellular C16:0 ceramides in both IMF and SS fractions was inversely related to overweight status (β = –0.432, P = 0.0095 and β = –0.443, P = 0.0058, respectively). These data indicate that meal ingestion has differing effects on SS ceramide subspecies and suggest that the fractional de novo synthesis of intramyocellular ceramide from plasma palmitate in the postprandial condition is reduced in those who are overweight.

Characterization of Monocyte-Associated Factor V

1993 ◽  
Vol 70 (02) ◽  
pp. 273-280 ◽  
Author(s):  
Janos Kappelmayer ◽  
Satya P Kunapuli ◽  
Edward G Wyshock ◽  
Robert W Colman
Keyword(s):  
Monoclonal Antibody ◽  
Light Chain ◽  
Peripheral Blood ◽  
De Novo ◽  
Factor V ◽  
Blood Monocytes ◽  
De Novo Synthesis ◽  
Hep G2 ◽  
Hep G2 Cells ◽  
Peripheral Blood Monocytes

SummaryWe demonstrate that in addition to possessing binding sites for intact factor V (FV), unstimulated peripheral blood monocytes also express activated factor V (FVa) on their surfaces. FVa was identified on the monocyte surface by monoclonal antibody B38 recognizing FVa light chain and by human oligoclonal antibodies H1 (to FVa light chain) and H2 (to FVa heavy chain) using immunofluorescence microscopy and flow cytometry. On Western blots, partially cleaved FV could be identified as a 220 kDa band in lysates of monocytes. In addition to surface expression of FVa, monocytes also contain intracellular FV as detected only after permeabilization by Triton X-100 by monoclonal antibody B10 directed specifically to the Cl domain not present in FVa. We sought to determine whether the presence of FV in peripheral blood monocytes is a result of de novo synthesis.Using in situ hybridization, no FV mRNA could be detected in monocytes, while in parallel control studies, factor V mRNA was detectable in Hep G2 cells and CD18 mRNA in monocytes. In addition, using reverse transcriptase and the polymerase chain reaction, no FV mRNA was detected in mononuclear cells or in U937 cells, but mRNA for factor V was present in Hep G2 cells using the same techniques. These data suggest that FV is present in human monocytes, presumably acquired by binding of plasma FV, and that the presence of this critical coagulation factor is not due to de novo synthesis.

Platelets Stimulate Thromboplastin Synthesis in Human Endothelial Cells

1983 ◽  
Vol 49 (02) ◽  
pp. 069-072 ◽  
Author(s):  
U L H Johnsen ◽  
T Lyberg ◽  
K S Galdal ◽  
H Prydz
Keyword(s):  
Endothelial Cells ◽  
De Novo ◽  
Umbilical Vein ◽  
Time Dependent ◽  
De Novo Synthesis ◽  
Human Endothelial Cells ◽  
Tumor Promotor ◽  
Coagulation Assay ◽  
Platelet Aggregates ◽  
Umbilical Vein Endothelial Cells

SummaryHuman umbilical vein endothelial cells in culture synthesize thromboplastin upon stimulation with phytohaemagglutinin (PHA) or the tumor promotor 12-O-tetradecanoyl-phorbol-13-acetate (TPA). The thromboplastin activity is further strongly enhanced in a time dependent reaction by the presence of gel-filtered platelets or platelet aggregates. This effect was demonstrable at platelet concentrations lower than those normally found in plasma, it may thus be of pathophysiological relevance. The thromboplastin activity increased with increasing number of platelets added. Cycloheximide inhibited the increase, suggesting that de novo synthesis of the protein component of thromboplastin, apoprotein III, is necessary.When care was taken to remove monocytes no thromboplastin activity and no apoprotein HI antigen could be demonstrated in suspensions of gel-filtered platelets, platelets aggregated with thrombin or homogenized platelets when studied with a coagulation assay and an antibody neutralization technique.

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