scholarly journals Studies on the assembly and secretion of a multicomponent protein. The biosynthesis of vitellogenin, an oestrogen-induced glycolipophosphoprotein

1973 ◽  
Vol 132 (3) ◽  
pp. 459-463 ◽  
Author(s):  
A. H. Merry ◽  
P. J. Dolphin ◽  
K. A. Munday ◽  
M. Akhtar
Keyword(s):  
Polypeptide Chain ◽  
Lag Phase ◽  
Pulse Labelling ◽  
Tissue Protein ◽  
Liver Slices ◽  
Single Protein ◽  
Time Required ◽  
Total Tissue ◽  
Cumulative Evidence

1. Incorporation of [32P]Pi and [3H]leucine into vitellogenin secreted in vitro by liver slices from oestrogen-treated Xenopus laevis is accompanied by a 2h lag; no lag is apparent for the incorporation into total tissue protein. 2. The addition of cycloheximide was found immediately to inhibit further incorporation of radioactive leucine into total tissue protein. The incorporation into secreted vitellogenin, however, continued for 2h after the addition of cycloheximide. 3. Pulse-labelling of liver slices with [3H]leucine for 30min, followed by a chase with a large excess of unlabelled leucine, resulted in the appearance of radioactivity in secreted vitellogenin from 90min after the end of the pulse period. 4. Evidence is presented which suggests that of the radioactivity from [3H]leucine incorporated into proteins by the liver of oestrogen-treated Xenopus some 70% is present in the single protein vitellogenin. 5. The incorporation of [32P]Pi into vitellogenin followed a pattern identical with that found for [3H]leucine in the pulse-labelling experiments and this indicates that synthesis of the polypeptide chain and incorporation of Pi are closely linked processes. 6. The cumulative evidence suggests that the 2h lag phase represents the time required for the assembly and secretion of this multicomponent protein.

scholarly journals Amino acids attached to transfer ribonucleic acid in vivo

1975 ◽  
Vol 150 (3) ◽  
pp. 419-432 ◽  
Author(s):  
M Butler ◽  
A Darbre ◽  
H R Arnstein
Keyword(s):  
Amino Acids ◽  
Liquid Chromatography ◽  
Ribonucleic Acid ◽  
Rabbit Liver ◽  
Gas Liquid Chromatography ◽  
Tissue Protein ◽  
Flame Ionization ◽  
Total Tissue

1. tRNA was extracted from rabbit liver by both the phenol and diethyl pyrocarbonate methods under conditions preventing deacylation of the amino acids attached in vivo. 2. After deacylation 12 amino acids were determined by gas-liquid chromatography, by using the flame-ionization and nitrogen-sensitive thermionic detectors. 3. Comparison of the distribution of 12 amino acids attached to tRNA with those contained in total tissue protein and in the free pool showed little correlation. 4. Results for the enzymic charging assay for tRNA in vitro did not correlate satisfactorily with the analysis of amino acids attached to tRNA in vivo. Marked differences were ntoed in comparison made between our own and other published results.

Delayed response of the mouse uterus to progesterone and oestradiol

1989 ◽  
Vol 1 (2) ◽  
pp. 107
Author(s):  
CM Murray ◽  
GM Stone
Keyword(s):  
Low Dose ◽  
In Vitro Metabolism ◽  
Delayed Response ◽  
Mouse Uterus ◽  
Tissue Protein ◽  
Ovariectomized Mouse ◽  
Oestradiol Benzoate ◽  
Long Acting ◽  
Total Tissue

The delayed response of the uterus of the ovariectomized mouse to progesterone (P) required the presence of a low dose of oestradiol-17 beta (E2) and was associated with a maintained level of uterine DNA, an increase in RNA:DNA ratio and in total tissue protein and a decreased level of uterine P. This last parameter was associated with an increased level of in vitro metabolism of P by the uterus. Changes in the level of receptors for P and E2 were temporally unrelated to the delayed response. Omission of oestradiol every second, third or fourth day inhibited development of the delayed response, which could also be obtained with the long acting progestogen, medroxy progesterone acetate, and E2 or oestradiol benzoate.

CORTICOSTEROID-UMSATZ UND CORTICOSTEROID-PRODUKTION BEI RATTEN UNTER DER BEHANDLUNG MIT ANABOLEN STEROIDEN

1965 ◽  
Vol 48 (2) ◽  
pp. 263-271 ◽  
Author(s):  
Herbert Schriefers ◽  
Gerlinde Scharlau ◽  
Franzis Pohl
Keyword(s):  
Production Rate ◽  
Adult Female ◽  
Anabolic Steroids ◽  
Reduction Rate ◽  
Female Rats ◽  
Adrenal Weight ◽  
Hydrogenase Activity ◽  
Anabolic Effect ◽  
Liver Slices

ABSTRACT After the administration of anabolic steroids to adult female rats in daily doses of 1 mg per animal for 14 days, the following parameters were investigated: the rate of the Δ4-5α-hydrogenase-catalyzed cortisone reduction in liver slices and microsomal fractions, the adrenal weight and the in vitro corticosterone production rate. Among the steroids tested, only 17α-methyl-testosterone and 17α-ethyl-19-nor-testosterone were effective in lowering significantly cortisone reduction rate by liver slices with concomitant decreases in microsomal Δ4-5α-hydrogenase-activity. Testosterone, 19-nor-testosterone, 17α-ethinyl-19-nor-testosterone, 17α-methyl-17β-hydroxy-androsta-1,4-dien-3-one and 1-methyl-17β-hydroxy-androst-1-en-3-one were ineffective or only slightly effective. Adrenal weight and absolute corticosterone production rate (μg/60 min per animal) were decreased after treatment with 17α-methyl-testosterone, 17α-ethyl-19-nor-testosterone and 1-methyl-17β-hydroxy-androst-1-en-3-one. Corticosterone production was decreased with 17α-ethinyl-19-nor-testosterone in spite of an unchanged adrenal weight. The relative corticosterone production rate (μg/60 min · 100 mg adrenal) was in any cases unaffected. According to these results there exists – with the exception of 17α-ethinyl-19-nor-testosterone – a strict parallelism between corticosteroid turnover and corticosterone production rate: unchanged turnover is correlated with unchanged corticosterone production rate, while a decreased turnover is correlated with decreased adrenal activity. The protein-anabolic effect of certain anabolic steroids may be partly due to an anti-catabolic action of these compounds resulting from a decreased corticosteroid inactivation and production rate. Possible mechanisms by which anabolic steroids may affect corticosteroid-balance are discussed.

scholarly journals Onset of acid-neutralizing action of a calcium/magnesium carbonate-based antacid using an artificial stomach model: an in vitro evaluation

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Maxim Voropaiev ◽  
Deborah Nock
Keyword(s):  
In Vitro Study ◽  
Magnesium Carbonate ◽  
Human Gastrointestinal Tract ◽  
Pepsin Activity ◽  
Onset Of Action ◽  
Over The Counter ◽  
Calcium Magnesium ◽  
Secondary Objective ◽  
Time Required

Abstract Background Calcium carbonate antacids are potent over-the-counter antacids, made more effective by adding magnesium carbonate (as in Rennie, Bayer). However, published studies on their onset of action are scarce. Therefore, we carried out an in vitro study comparing Rennie and placebo under simulated conditions of the human stomach (artificial stomach model) to reconfirm the onset of action of Rennie. Methods The validated Simulator of the Human Intestinal Microbial Ecosystem apparatus (SHIME, ProDigest, Belgium) was used, comprising five reactors simulating different parts of the human gastrointestinal tract. Both Rennie and placebo were dosed at two tablets per incubation over six independent, 2-h stomach incubations each. Primary objectives: to evaluate the time required to achieve pH 3.0, 3.5, 4.0 and 4.5, as well as the maximum pH reached. Secondary objective: to evaluate pepsin activity over the entire 2-h gastric incubation. Results After addition of Rennie, the gastric medium reached a pH of 3.0 within 40 s. The maximum pH of 5.24 was maintained for almost 10 min. In contrast, the maximum pH with placebo was 1.28 during the entire gastric simulation. Furthermore, Rennie strongly reduced the activity of mucosa-damaging pepsin during the period of increased pH. With placebo, the lower pH resulted in consistently high loads of digested peptides, reflecting the high cumulative and instantaneous pepsin activity. Conclusions New data is a critical component in informed decision making. Our data confirm the high efficacy and fast onset of acid-neutralizing action of Rennie, which begins to work within seconds.

Precision-cut Guinea-pig Liver Slices as a Tool for Studying the Toxicity of Volatile Anaesthetics

1990 ◽  
Vol 18 (1_part_1) ◽  
pp. 191-199
Author(s):  
Hanan N. Ghantous ◽  
Jeanne Fernando ◽  
Scott E. Morgan ◽  
A. Jay Gandolfi ◽  
Klaus Brandel
Keyword(s):  
Guinea Pig ◽  
Rank Order ◽  
Normal Liver ◽  
Liver Slice ◽  
Volatile Anaesthetics ◽  
Pig Liver ◽  
Liver Slices ◽  
Guinea Pig Liver ◽  
Krebs Henseleit Buffer

Cultured precision-cut liver slices retain normal liver architecture and physiological biochemical functions. Hartley male guinea-pig liver slices have proven to be a good model for studying the biotransformation and toxicity of halothane. This system was used to evaluate the biotransformation and toxicity of different volatile anaesthetics (halothane, enflurane, isoflurane and sevoflurane), and compare their effects to those of new anaesthetics (desflurane). Liver slices (250–300μm thick) were incubated in sealed roller vials, containing Krebs Henseleit buffer at 37°C under 95% O2:5% CO2 atmosphere. Volatile anaesthetics were delivered by volatilisation after pre-incubation for 1 hour to produce a constant concentration in the medium. Production of the metabolites, trifluroacetic acid and fluoride ion, was measured. Intracellular potassium ion content, protein synthesis and secretion were determined as indicators of viability of the slices. The rank order of biotransformation of anaesthetics by the liver slices was halothane >sevoflurane>isoflurane and enflurane>desflurane. The rank order of hepatotoxicity of these anaesthetics was halothane>isoflurane and enflurane>sevoflurane and desflurane. Halothane is the anaesthetic which is metabolised furthest and has the most toxic effect, while desflurane is the least metabolised anaesthetic and has the least toxicity. This in vitro cultured precision-cut liver slice system appears to be suitable for studying the biotransformation of volatile anaesthetics and correlating its role in the resulting toxicity.

scholarly journals Entrapment of the Fastest Known Carbonic Anhydrase with Biomimetic Silica and Its Application for CO2 Sequestration

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2452
Author(s):  
Chia-Jung Hsieh ◽  
Ju-Chuan Cheng ◽  
Chia-Jung Hu ◽  
Chi-Yang Yu
Keyword(s):  
Carbonic Anhydrase ◽  
High Activity ◽  
Co2 Sequestration ◽  
Residual Activity ◽  
Entrapment Efficiency ◽  
Free Form ◽  
Uncatalyzed Reaction ◽  
The Stability ◽  
Time Required

Capturing and storing CO2 is of prime importance. The rate of CO2 sequestration is often limited by the hydration of CO2, which can be greatly accelerated by using carbonic anhydrase (CA, EC 4.2.1.1) as a catalyst. In order to improve the stability and reusability of CA, a silica-condensing peptide (R5) was fused with the fastest known CA from Sulfurihydrogenibium azorense (SazCA) to form R5-SazCA; the fusion protein successfully performed in vitro silicification. The entrapment efficiency reached 100% and the silicified form (R5-SazCA-SP) showed a high activity recovery of 91%. The residual activity of R5-SazCA-SP was two-fold higher than that of the free form when stored at 25 °C for 35 days; R5-SazCA-SP still retained 86% of its activity after 10 cycles of reuse. Comparing with an uncatalyzed reaction, the time required for the onset of CaCO3 formation was shortened by 43% and 33% with the addition of R5-SazCA and R5-SazCA-SP, respectively. R5-SazCA-SP shows great potential as a robust and efficient biocatalyst for CO2 sequestration because of its high activity, high stability, and reusability.

scholarly journals In vitro metabolism of rumenic acid in bovine liver slices

2005 ◽  
Vol 45 (4) ◽  
pp. 441-451 ◽  
Author(s):  
Anne De La Torre ◽  
Dominique Gruffat ◽  
Jean-Michel Chardigny ◽  
Jean-Louis Sebedio ◽  
Denys Durand ◽  
...  
Keyword(s):  
Bovine Liver ◽  
In Vitro Metabolism ◽  
Liver Slices

scholarly journals Chemical Validation of Phosphodiesterase C as a Chemotherapeutic Target in Trypanosoma cruzi, the Etiological Agent of Chagas' Disease

2010 ◽  
Vol 54 (9) ◽  
pp. 3738-3745 ◽  
Author(s):  
Sharon King-Keller ◽  
Minyong Li ◽  
Alyssa Smith ◽  
Shilong Zheng ◽  
Gurpreet Kaur ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Catalytic Domain ◽  
Polypeptide Chain ◽  
Inflammatory Diseases ◽  
New Drugs ◽  
Volume Recovery ◽  
Chronic Pulmonary Diseases ◽  
Potential Inhibitors

ABSTRACT Trypanosoma cruzi phosphodiesterase (PDE) C (TcrPDEC), a novel and rather unusual PDE in which, unlike all other class I PDEs, the catalytic domain is localized in the middle of the polypeptide chain, is able to hydrolyze cyclic GMP (cGMP), although it prefers cyclic AMP (cAMP), and has a FYVE-type domain in its N-terminal region (S. Kunz et al., FEBS J. 272:6412-6422, 2005). TcrPDEC shows homology to the mammalian PDE4 family members. PDE4 inhibitors are currently under development for the treatment of inflammatory diseases, such as asthma, chronic pulmonary diseases, and psoriasis, and for treating depression and serving as cognitive enhancers. We therefore tested a number of compounds originally synthesized as potential PDE4 inhibitors on T. cruzi amastigote growth, and we obtained several useful hits. We then conducted homology modeling of T. cruzi PDEC and identified other compounds as potential inhibitors through virtual screening. Testing of these compounds against amastigote growth and recombinant TcrPDEC activity resulted in several potent inhibitors. The most-potent inhibitors were found to increase the cellular concentration of cAMP. Preincubation of cells in the presence of one of these compounds stimulated volume recovery after hyposmotic stress, in agreement with their TcrPDEC inhibitory activity in vitro, providing chemical validation of this target. The compounds found could be useful tools in the study of osmoregulation in T. cruzi. In addition, their further optimization could result in the development of new drugs against Chagas' disease and other trypanosomiases.

Synthesis and turnover of proteins and mRNA in germinating wheat embryos

1982 ◽  
Vol 60 (3) ◽  
pp. 389-397 ◽  
Author(s):  
Zbyszko F. Grzelczak ◽  
Mark H. Sattolo ◽  
Linda K. Hanley-Bowdoin ◽  
Theresa D. Kennedy ◽  
Byron G. Lane
Keyword(s):  
Growth Phase ◽  
Time Course ◽  
Phase 1 ◽  
Major Product ◽  
Lag Phase ◽  
Wheat Embryo ◽  
Phase Development ◽  
Wheat Embryos

The most prominent methionine-labeled protein made when cell-free systems are programmed with bulk mRNA from dry wheat embryos has been identified with what may be the most abundant protein in dry wheat embryos. The protein has been brought to purity and has a distinctive amino acid composition, Gly and Glx accounting for almost 40% of the total amino acids. Designated E because of its conspicuous association with early imbibition of dry wheat embryos, the protein and its mRNA are abundant during the "early" phase (0–1 h) of postimbibition development, and easily detected during "lag" phase (1–5 h), but they are almost totally degraded soon after entry into the "growth" phase of development, by about 10 h postimbibition.The most prominent methionine-labeled protein peculiar to the cell-free translational capacity of bulk mRNA from "growth" phase embryos is not detected as a product of in vivo synthesis. Its electrophoretic properties and its time course of emergence, after 5 h postimbibition development, suggest that this major product of cell-free synthesis may be an in vitro counterpart to a prominent methionine-labeled protein made only in vivo, by "growth" phase embryos. Designated G because of its conspicuous association with "growth" phase development, the cell-free product does not comigrate with any prominent dye-stained band in electrophoretic distributions of wheat proteins. The suspected cellular counterpart to G, also, does not comigrate with a prominent dye-stained wheat protein during electrophoresis, and although found in particulate as well as soluble fractions of wheat embryo homogenates it is not concentrated in either nuclei or mitochondria, as isolated.

Studies on the induction of rat hepatic CYP1A, CYP2B, CYP3A and CYP4A subfamily form mRNAs in vivo and in vitro using precision-cut rat liver slices

Xenobiotica ◽  
2003 ◽  
Vol 33 (5) ◽  
pp. 511-527 ◽  
Author(s):  
C. Meredith ◽  
M. P. Scott ◽  
A. B. Renwick ◽  
R. J. Price ◽  
B. G. Lake
Keyword(s):  
Rat Liver ◽  
Liver Slices
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