scholarly journals Ribonucleic acid synthesis in the renal cortex at the initiation of compensatory growth

1976 ◽  
Vol 158 (2) ◽  
pp. 457-470 ◽  
Author(s):  
P Cortes ◽  
N W Levin ◽  
P R Martin
Keyword(s):  
Rna Synthesis ◽  
Compensatory Growth ◽  
Renal Cortex ◽  
Acid Synthesis ◽  
Sham Operation ◽  
Precursor Pool ◽  
Cortex Slices ◽  
Endogenous Precursor

The mechanisms responsible for the increase in RNA per cell during the first 48h of renal compensatory growth were studied in the renal cortex. Unilaterally nephrectomized, sham-operated or non-operated rats were used. Incorporation into RNA of labelled precursors was studied in vivo and in vitro. Sham-operation produced significant changes in precursor incorporation, absolute amounts of UTP and RNA, and the rate of RNA synthesis. At 6h after surgery, the amount of RNA decreased in sham-operated controls, whereas that in growing cortex remained unchanged. Incorporation into RNA in vivo was greater in the growing cortex, although the rate of RNA synthesis was not increased. At 24h, precursor incorporation into RNA and UTP and RNA synthesis were all increased in the growing cortex. In contrast with results obtained in vivo, slices of growing cortex incorporated less labelled precursor into RNA than did cortex slices from sham-operated controls, from 3 to 48h. Maximal differences were found from 6 to 24h. An attempt was made to equalize endogenous precursor pool sizes by increasing the concentration of unlabelled uridine in the media; incorporation differences were narrowed significantly. Serum from nephrectomized animals did not increase precursor incorporation into RNA in vitro. An increase in RNA synthesis is an important factor in RNA accretion in the renal cortex beyond 12h of compensatory growth. This is accompanied by increased UTP content and preceded by expansion of other pools. The amount of labelled precursor incorporated into RNA is greatly influenced by its delivery rate to the growing kidney in vivo and by intracellular dilution of expanded precursor pools in vitro.

Ribonucleic acid synthesis inPlasmodium knowlesimaintained bothin vivoandin vitro

Parasitology ◽  
1975 ◽  
Vol 71 (2) ◽  
pp. 199-209 ◽  
Author(s):  
P. I. Trigg ◽  
P. G. Shakespeare ◽  
Susan J. Burt ◽  
Sally I. Kyd
Keyword(s):  
Ribosomal Rna ◽  
Rna Synthesis ◽  
Nuclear Division ◽  
Plasmodium Knowlesi ◽  
Acid Synthesis ◽  
Agarose Gel Electrophoresis ◽  
Trophozoite Stage ◽  
Late Trophozoite

RNA extracted from purified parasites ofPlasmodium knowlesiwas fractionated using agarose gel electrophoresis. Preparations from parasites grown bothin vivoandin vitrocontained species of RNA with sedimentation coefficients of 4·0S, 5·0S, 16·6S, 24·2S, 31·4S, 38·0S and 48·3S. There was less RNA present in parasites grownin vitrothan the equivalent stage parasites grownin vivobut the proportional amounts of the various species of RNA was similar in both cases. It is suggested that the 24·2S and 16·6S species of RNA are ribosomal and that the high molecular weight 31·4S, 38·0S and 48·0S species are ribosomal precursors. Ribosomal RNA synthesis occurs throughout the cell cycle during growth from the ring to the schizont stage; maximum incorporation of [H3]-adenosine occurs at the late trophozoite stage before nuclear division.

ACTION OF KI, THYROXINE AND CYCLIC AMP ON [3H]URIDINE INCORPORATION INTO THE RNA OF THYROID SLICES

1976 ◽  
Vol 83 (2) ◽  
pp. 313-320 ◽  
Author(s):  
Mario A. Pisarev ◽  
Leonardo O. Aiello ◽  
Diana L. Kleiman de Pisarev
Keyword(s):  
Cyclic Amp ◽  
Inhibitory Action ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Protein Biosynthesis ◽  
Rna Degradation ◽  
Precursor Pool ◽  
Rna Precursor

ABSTRACT Potassium iodide (KI) has been shown to impair thyroid protein biosynthesis both in vivo and in vitro. The present study was performed in order to clarify its mechanism of action. Ribonucleic acid (RNA) synthesis was studied in beef thyroid slices with either [32P] or [3H]-uridine as labelled precursors. Both KI and thyroxine (T4) at 10−5 m significantly decreased RNA labelling under our conditions. In other experiments RNA degradation was examined in pulse-labelled and actinomycin D-treated slices. KI did not modify the degradation of the [3H]-RNA thus indicating that it interferes with the biosynthesis rather than with the degradation of RNA. Taking the perchloric acid soluble radioactivity as a rough index of the precursor pool the present results would indicate an action at this level. Both KClO4 and methylmercapto-imidazole relieved the gland from the inhibitory action of KI, supporting the view that an intracellular and organified form of iodine is responsible for this action. Since T4 also reproduced the effects of KI on RNA synthesis we would like to propose iodothyronines as the intermediates of this action. Cyclic AMP has been shown to stimulate thyroid protein biosynthesis. The present results demonstrate an action at the RNA level. Cyclic AMP increased both the PCA-soluble and RNA-linked radioactivity, thus suggesting an effect at the RNA precursor pool. KI at 10−5 m blocked the action of 2 mm cyclic AMP.

Demethylation of 3-O-methyldopa in the kidney: a possible source for dopamine in urine

1996 ◽  
Vol 270 (5) ◽  
pp. F862-F868 ◽  
Author(s):  
F. R. Ibarra ◽  
J. Aguirre ◽  
S. Nowicki ◽  
M. Barontini ◽  
E. E. Arrizurieta ◽  
...  
Keyword(s):  
Renal Cortex ◽  
Proximal Tubules ◽  
Maximal Velocity ◽  
Velocity Condition ◽  
Male Wistar Rats ◽  
Cortex Slices ◽  
Dose Dependent ◽  
Proximal Tubule Segments

The possibility that demethylation of 3-O-methyldopa (OM-dopa) in the kidney could provide a source for dopamine in the urine was explored in male Wistar rats aged 60-90 days, using in vivo and in vitro approaches. The results showed that endogenous OM-dopa is filtered, reabsorbed and extensively metabolized in the kidney. Infusion of OM-dopa into anesthetized rats increased significantly urinary excretion of Na+, dopa, dopamine, and 3,4 dihydroxyphenylacetic acid. Whole kidney homogenates, slices from renal cortex, and microdissected proximal tubules produced significant amounts of both dopa and dopamine when incubated with OM-dopa. Renal cortex slices produced dose-dependent amounts of dopa and dopa-mine when incubated with 1-100 microM OM-dopa. Incubation of microdissected proximal tubule segments with 1 microM OM-dopa produced a fourfold (P < 0.025) increment in dopa and a twofold (P < 0.05) increment in dopamine (an effect similar to that observed with 1 microM L-dopa). One micromolar OM-dopa or 1 microM L-dopa decreased (P < 0.05) Na(+)-K(+)-adenosinetriphosphatase activity measured at maximal velocity condition in proximal tubules. In conclusion, these experiments show that in vitro the kidney is able to produce dopamine by demethylation of OM-dopa, while the results of the OM-dopa infusion suggest that this conversion may also occur in vivo.

Nuclear p26, a small heat shock/α-crystallin protein, and its relationship to stress resistance in Artemia franciscana embryos

2001 ◽  
Vol 204 (13) ◽  
pp. 2339-2350 ◽  
Author(s):  
Julia K. Willsie ◽  
James S. Clegg
Keyword(s):  
Heat Shock ◽  
Rna Synthesis ◽  
Low Ph ◽  
Artemia Franciscana ◽  
Precursor Pool ◽  
In Vivo Experiments ◽  
Nuclear Targets

SUMMARY The role of the small heat shock/α-crystallin protein, p26, in transcription in Artemia franciscana embryos was examined using isolated nuclei, containing either control or elevated levels of p26, in transcription run-on assays. Heat shock or anoxia in vivo and acid pH in vitro were used to transfer p26 into nuclei. The results suggest that parameters other than, or in addition to, p26 are responsible for the reduced transcription rates observed and that decreases in pHi are involved. In vivo experiments indicate that RNA synthesis and, to a lesser extent, protein synthesis are downregulated in intact embryos recovering from heat shock and that the precursor pool is not limiting. Confocal microscopy confirmed that p26 moves into nuclei in response to heat shock and anoxia in vivo, and to low pH in vitro, and indicated that the nuclear distribution of p26 is similar under all three conditions. We present evidence that unstressed (control) embryos containing p26 in all their nuclei will not hatch, even under permissive conditions, and propose that they are unable to terminate diapause. Potential nuclear targets of p26 chaperone activity are discussed.

Characteristics of in vitro ammonia and glucose production by dog kidney cortex

1975 ◽  
Vol 228 (3) ◽  
pp. 934-943 ◽  
Author(s):  
P Cartier ◽  
P Belanger ◽  
G Lemieux
Keyword(s):  
Renal Cortex ◽  
Left Kidney ◽  
Glucose Production ◽  
Kidney Cortex ◽  
Significant Difference ◽  
Dog Kidney ◽  
Cortex Slices ◽  
The Right

Renal cortex slices from acidotic dogs incubated with L-glutamine 1 mM at pH 7.05 produced more ammonia and glucose than slices from nonacidotic animals but no significant difference could be demonstrated at pH 7.48. At a phosphate concentration of 20-30 mM in the medium, a 20-30% increase in ammonia and a 25-40% decrease in glucose production were observed. At L-glutamine concentrations from 0 to 8 mM, a curvilinear increase in both ammonia and glucose production was noted, the effect being greater in slices from acidotic animals. D-Glutamine had little effect on ammoniagenesis. Ammonia production (1 mM L-glutamine) in vitro was 50% lower in acidotic dogs than in vivo. Slices from the remnant left kidney (4-6 wk after right nephrectomy) did not behave differently during acidosis than those from the right kidney with regard to ammonia or glucose production. In vitro ammonia and glucose production was higher in the rat than in the dog in acidotic and nonacidotic conditions when comparable concentrations of L-glutamine substrate were used.

scholarly journals Ribonucleic acid synthesis in vitro in primary spermatocytes isolated from rat testis

1977 ◽  
Vol 168 (1) ◽  
pp. 23-31 ◽  
Author(s):  
J. Anton Grootegoed ◽  
Anne H. Grollé-Hey ◽  
Focko F. G. Rommerts ◽  
Henk J. Van Der Molen
Keyword(s):  
Electrophoretic Mobility ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Marked Change ◽  
Acid Synthesis ◽  
Specific Pattern ◽  
28S Rrna ◽  
Phenol Extraction

The incorporation of [3H]uridine into RNA was studied quantitatively (by incorporation of [3H]uridine into acid-precipitable material) and qualitatively (by phenol extraction and electrophoretic separation of RNA in polyacrylamide gels) in preparations enriched in primary spermatocytes, obtained from testes of rats 26 or 32 days old. The rate of incorporation of [3H]uridine into RNA of isolated spermatocytes was constant during the first 8h of incubation, after which it decreased, but the decreased rate of incorporation was not reflected in a marked change in electrophoretic profiles of labelled RNA. In isolated spermatocytes, [3H]uridine was incorporated mainly into heterogeneous RNA with a low electrophoretic mobility. Most of this RNA was labile, as shown when further RNA synthesis was inhibited with actinomycin D. Spermatocytes in vivo also synthesized heterogeneous RNA with a low electrophoretic mobility. A low rate of incorporation of [3H]uridine into rRNA of isolated spermatocytes was observed. The cleavage of 32S precursor rRNA to 28S rRNA was probably retarded in spermatocytes in vitro as well as in vivo. RNA synthesis by preparations enriched in early spermatids or Sertoli cells was qualitatatively different from RNA synthesis by the spermatocyte preparations. It is concluded that isolated primary spermatocytes maintain a specific pattern of RNA synthesis, which resembles RNA synthesis in spermatocytes in vivo. Therefore isolated spermatocytes of the rat can be used for studying the possible regulation of RNA synthesis during the meiotic prophase.

scholarly journals E3 ubiquitin ligase Grail promotes hepatic steatosis through Sirt1 inhibition

2021 ◽  
Vol 12 (4) ◽  
Author(s):  
Pei-Yao Liu ◽  
Cheng-Cheung Chen ◽  
Chia-Ying Chin ◽  
Te-Jung Liu ◽  
Wen-Chiuan Tsai ◽  
...  
Keyword(s):  
Hepatic Steatosis ◽  
Lipid Accumulation ◽  
Acid Synthesis ◽  
Sirtuin 1 ◽  
Nonalcoholic Fatty Liver ◽  
Expression Of Genes ◽  
Hepatic Fat ◽  
Underlying Mechanisms

AbstractIn obese adults, nonalcoholic fatty liver disease (NAFLD) is accompanied by multiple metabolic dysfunctions. Although upregulated hepatic fatty acid synthesis has been identified as a crucial mediator of NAFLD development, the underlying mechanisms are yet to be elucidated. In this study, we reported upregulated expression of gene related to anergy in lymphocytes (GRAIL) in the livers of humans and mice with hepatic steatosis. Grail ablation markedly alleviated the high-fat diet-induced hepatic fat accumulation and expression of genes related to the lipid metabolism, in vitro and in vivo. Conversely, overexpression of GRAIL exacerbated lipid accumulation and enhanced the expression of lipid metabolic genes in mice and liver cells. Our results demonstrated that Grail regulated the lipid accumulation in hepatic steatosis via interaction with sirtuin 1. Thus, Grail poses as a significant molecular regulator in the development of NAFLD.

scholarly journals INHIBITING EFFECT OF THE NEW CYTOTOXIC ANTIBIOTIC DAUNOMYCIN ON NUCLEIC ACIDS AND MITOTIC ACTIVITY OF HELA CELLS

1965 ◽  
Vol 27 (3) ◽  
pp. 545-550 ◽  
Author(s):  
A. Di Marco ◽  
R. Silvestrini ◽  
S. Di Marco ◽  
T. Dasdia
Keyword(s):  
Mitotic Activity ◽  
Rna Synthesis ◽  
Thymidine Incorporation ◽  
Acid Synthesis ◽  
Acetyl Derivative ◽  
Total Inhibition ◽  
Nuclear Rna ◽  
Nucleolar Rna ◽  
Higher Doses

The effect has been studied of Actinomycin D, Daunomycin (Da.), and Da. N acetyl derivative on mitotic activity and on the nucleic acid synthesis of in vitro HeLa cell cultures. The experiments were carried out by means of the radioautographic technique using stripping films. The relative uptake of thymidine-H3 and uridine-H3 was determined by means of the reduced silver grain count present in the nuclei of controls and treated cells. The mitotic activity and thymidine incorporation were noticeably reduced by Daunomycin and Actinomycin, whereas both processes appeared less affected by Da. N acetyl derivative. As regards nuclear RNA synthesis, all three antibiotics at low doses chiefly inhibit nucleolar RNA synthesis. On the other hand, whilst Actinomycin at higher doses causes an almost total inhibition of the synthesis of the whole nuclear RNA, in Daunomycin- and Da. N acetyl derivative-treated cells extranucleolar RNA synthesis is less susceptible to inhibition.

Studies of two temperature-sensitive mutants of Mengo virus

1979 ◽  
Vol 57 (6) ◽  
pp. 902-913 ◽  
Author(s):  
Patrick W. K. Lee ◽  
John S. Colter
Keyword(s):  
Rna Synthesis ◽  
Viral Rna ◽  
Temperature Sensitive ◽  
Supporting Evidence ◽  
Structural Polypeptide ◽  
Infected Cells ◽  
Mengo Virus ◽  
In Vitro Stability

Studies of the synthesis of viral ribonucleates and polypeptides in cells infected with two RNA−ts mutants of Mengo virus (ts 135 and ts 520) have shown that when ts 135 infected cells are shifted from the permissive (33 °C) to the nonpermissive (39 °C) temperature: (i) the synthesis of all three species of viral RNA (single stranded, replicative form, and replicative intermediate) is inhibited to about the same extent, and (ii) the posttranslational cleavage of structural polypeptide precursors A and B is partially blocked. Investigations of the in vivo and in vitro stability of the viral RNA replicase suggest that the RNA− phentotype reflects a temperature-sensitive defect in the enzyme. The second defect does not appear to result from the inhibition of viral RNA synthesis at 39 °C, since normal cleavage of polypeptides A and B occurs in wt Mengo-infected cells in which viral RNA synthesis is blocked by cordycepin, and at the nonpermissive temperature in ts 520 infected cells. Considered in toto, the evidence suggests that ts 135 is a double mutant.Subviral (53 S) particles have been shown to accumulate in ts 520 (but not ts 135) infected cells when cultures are shifted from 33 to 39 °C. This observation provides supporting evidence for the proposal that this recently discovered particle is an intermediate in the assembly pathway of Mengo virions.

Phosphoenolpyruvate carboxylase during grape berry development: protein level, enzyme activity and regulation

2000 ◽  
Vol 27 (3) ◽  
pp. 221 ◽  
Author(s):  
Paraskevi Diakou ◽  
Laurence Svanella ◽  
Philippe Raymond ◽  
Jean-Pierre Gaudillère ◽  
Annick Moing
Keyword(s):  
Malic Acid ◽  
Protein Level ◽  
Phosphoenolpyruvate Carboxylase ◽  
Phosphorylation Site ◽  
Acid Synthesis ◽  
Grape Berry ◽  
Vitis Vinifera L ◽  
Normal Acid

The protein level and regulation of phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31, involved in malic acid synthesis) was studied during the fruit development of two grape (Vitis vinifera L.) varieties, ‘Cabernet Sauvignon’ and ‘Gora Chirine’, with berries of normal and low organic acid content, respectively. The protein level and in vitro activity were higher in the low-acid variety than in the normal-acid variety for most stages. In vivo PEPC activity, measured using 14 CO2 labelling, was significantly higher in the low-acid variety than in the normal-acid variety about 1 week before and 1 week after veraison (the day which corresponds to the onset of ripening). However, partitioning into malate was the same for both varieties. Antibodies raised against the N-terminal part of SorghumPEPC recognised the grape berry PEPC, indicating the presence of the consensus phosphorylation site involved in PEPC regulation. PEPC phosphorylation status was estimated by studying sensitivity to pH and malate. Grape berry PEPC appeared more sensitive to low pH and malate during ripening (IC50 malate, 0.2–0.7 mM) compared to during the earlier stages of development (IC50 malate, 1.2–2 mM) for both varieties. Therefore, in the normal-acid variety, PEPC seems to participate in controlling malic acid accumulation but does not seem to control the differences in malic acid concentration observed between the two varieties.

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