scholarly journals PROTEINS IN NUCLEOCYTOPLASMIC INTERACTIONS

1967 ◽  
Vol 33 (3) ◽  
pp. 637-644 ◽  
Author(s):  
Lester Goldstein ◽  
David M. Prescott
Keyword(s):  
Amino Acid ◽  
Amoeba Proteus ◽  
Nuclear Proteins ◽  
Quantitative Assay ◽  
Protein Breakdown ◽  
High Concentration ◽  
And Migration ◽  
Triton X ◽  
Slow Turnover ◽  
Nucleocytoplasmic Interactions

By the transplantation of amino acid-3H-labeled nuclei between cells and the subsequent isolation of nuclei for quantitative assay, we have confirmed that all the nuclear proteins of Amoeba proteus are divisible into two classes that are sharply defined by their physiological behavior. About 40% of the proteins in the nucleus rapidly migrates back and forth between the nucleus and the cytoplasm. These rapidly migrating proteins (RMP) are 25–50 times more concentrated in the nucleus than in the cytoplasm, and migration into the nucleus therefore occurs against a high concentration differential. The remaining 60% of nuclear proteins has been classified as slow turnover proteins (STP) since (as reported in a following paper) virtually all of them ultimately undergo turnover. Turnover in this context means loss of label from the nucleus, by either protein breakdown or protein migration to the cytoplasm. Isolation of nuclei in the detergent Triton X-100 results in a 20% loss of nuclear proteins but conclusions about RMP and STP were not found to be significantly affected by this loss.

scholarly journals PROTEINS IN NUCLEOCYTOPLASMIC INTERACTIONS

1968 ◽  
Vol 39 (2) ◽  
pp. 404-414 ◽  
Author(s):  
David Prescott ◽  
Lester Goldstein
Keyword(s):  
Binding Sites ◽  
Interphase Nucleus ◽  
Nuclear Protein ◽  
Protein A ◽  
Amoeba Proteus ◽  
Nuclear Proteins ◽  
Nuclear Transplantation ◽  
Amino Acid Labeling ◽  
Turn Over ◽  
Nucleocytoplasmic Interactions

The behavior of nuclear proteins in Amoeba proteus was studied by tritiated amino acid labeling, nuclear transplantation, and cytoplasmic amputation. During prophase at least 77% (but probably over 95%) of the nuclear proteins is released to the cytoplasm. These same proteins return to the nucleus within the first 3 hr of interphase. When cytoplasm is amputated from an ameba in mitosis (shen the nuclear proteins are in the cytoplasm), the resultant daughter nuclei are depleted in the labeled nuclear proteins. The degree of depletion is less than proportional to the amount of cytoplasm removed because a portion of rapidly migrating protein (a nuclear protein that is normally shuttling between nucleus and cytoplasm and is thus also present in the cytoplasm) which would normally remain in the cytoplasm is taken up by the reconstituting daughter nuclei. Cytoplasmic fragments cut from mitotic cells are enriched in both major classes of nuclear proteins, i.e. rapidly migrating protein and slow turn-over protein. An interphase nucleus implanted into such an enucleated cell acquires from the cytoplasm essentially all of the excess nuclear proteins of both classes. The data indicate that there is a lack of binding sites in the cytoplasm for the rapidly migrating nuclear protein. The quantitative aspects of the distribution of rapidly migrating protein between the nucleus and the cytoplasm indicate that the distribution is governed primarily by factors within the nucleus.

scholarly journals PROTEINS IN NUCLEOCYTOPLASMIC INTERACTIONS

1968 ◽  
Vol 36 (1) ◽  
pp. 53-61 ◽  
Author(s):  
Lester Goldstein ◽  
David M. Prescott
Keyword(s):  
Cell Division ◽  
Nuclear Protein ◽  
Amoeba Proteus ◽  
Rapid Rate ◽  
Cell Nuclei ◽  
Protein Label ◽  
Protein Classes ◽  
Host Nucleus ◽  
Slow Turnover ◽  
Nucleocytoplasmic Interactions

In previous studies, we showed that essentially all the proteins of the Amoeba proteus nucleus could be classified either as Rapidly Migrating Proteins (RMP), which shuttle between nucleus and cytoplasm continuously at a relatively rapid rate during interphase, or as Slow Turnover Proteins (STP), which seem to move hardly at all during interphase. In this paper, we report on the kinetics and direction of the movement of both classes of protein, as well as on aspects of their localization, with and without growth. The effects of growth were observed with and without cell division. These nuclear proteins have been studied in several ways: by transplantation of labeled nuclei into unlabeled cells and noting the rate of distribution to cytoplasm and host cell nuclei; by repeated amputation of cytoplasm from labeled cells—with and without initially labeled cytoplasm—each amputation being followed by refeeding on unlabeled food; by noting the redistribution of the various protein classes following growth and cell division. The data show (a) labeled RMP equilibrate between a grafted labeled nucleus and an unlabeled host nucleus in ca. 3 hr, but are detectable in the latter less than 30 min after the operation; (b) STP label does, indeed, leave the nucleus and does so at a rate of ca. 25% of the nuclear total per cell generation (ca. 36–40 hr at 23°C); (c) the cytoplasm appears to have a reserve of material that is converted to RMP; (d) when labeled cells are amputated just before they would have divided and are refed unlabeled food after each amputation, there is a loss of 20–25% of the nuclear protein label with each amputation; (e) under the latter circumstances, an essentially complete turnover of all nuclear protein can be demonstrated.

scholarly journals Tuned S-Scheme Cu2S_TiO2_WO3 Heterostructure Photocatalyst toward S-Metolachlor (S-MCh) Herbicide Removal

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2231
Author(s):  
Alexandru Enesca ◽  
Luminita Isac
Keyword(s):  
Sol Gel ◽  
Annealing Treatment ◽  
Atomic Ratio ◽  
High Concentration ◽  
Step Procedure ◽  
Constant Rate ◽  
Efficient Charge ◽  
Crystallite Sizes ◽  
Oxygen Excess ◽  
And Migration

A dual S-scheme Cu2S_TiO2_WO3 heterostructure was constructed by sol–gel method using a two-step procedure. Due to the synthesis parameters and annealing treatment the heterostructure is characterized by sulfur deficit and oxygen excess allowing the passivation of oxygen vacancies. The photocatalytic activity was evaluated under UV and UV–Vis irradiation scenarios using S-MCh as reference pollutant. The heterostructure is composed on orthorhombic Cu2S, anatase TiO2 and monoclinic WO3 with crystallite sizes varying from 65.2 Å for Cu2S to 97.1 Å for WO3. The heterostructure exhibit a dense morphology with pellets and particle-like morphology closely combined in a relatively compact assembly. The surface elemental composition indicate that the heterostructure maintain a similar atomic ratio as established during the synthesis with a slight sulfur deficit due to the annealing treatments. The results indicate that the three-component heterostructure have higher photocatalytic efficiency (61%) comparing with two-component heterostructure or bare components. Moreover, Cu2S_TiO2_WO3 exhibit a superior constant rate (0.114 s−1) due to the high concentration of photogenerated charge carriers, efficient charge separation and migration.

The Synthesis and Migration of Nuclear Proteins during Mitosis and differentiation of Cells in Rats

1965 ◽  
Vol s3-106 (75) ◽  
pp. 229-240
Author(s):  
R. T. SIMS
Keyword(s):  
Granular Cell ◽  
Nuclear Proteins ◽  
Photographic Emulsion ◽  
Metaphase Chromosomes ◽  
Interphase Nuclei ◽  
Cell Layers ◽  
The Difference ◽  
Mitotic Figures ◽  
And Migration ◽  
Silver Grains

Hooded rats were given an intraperitoneal injection of 3H-tyrosine, and killed in pairs 10 min, 30 min, 12 h, 36 h, 7 days, and 30 days later. A piece of skin with white growing hair, and the tongue, were taken from each animal and radioautographs were prepared. Silver grains were counted over whole nuclei and whole mitotic figures of the germinal cells and whole nuclei of differentiating cells of both tissues. It was found that the interphase nuclei have significantly more silver grains over them than the chromosomes at all stages of mitosis and there are virtually no grains over metaphase, anaphase, and early telophase chromosomes in both tissues of all the animals killed up to 36 h after the injection. The difference between the grain counts over the interphase nuclei and the chromosomes of dividing cells is at least 20-fold at 30 min in the hair matrix, at least 5-fold at 30 min in the tongue and at 36 h in both tissues. It was established that the differences observed between the radioactivities of the nuclei and chromosomes of mitotic figures are real from estimates of: the radioactivity of the cell cytoplasm, volumes of the metaphase chromosomes and interphase nuclei within 1µ of the photographic emulsion, and the volumes of cytoplasm separating the photographic emulsion and these structures. No protein synthesis was demonstrable in the chromosomes during metaphase, anaphase, and early telophase. Nuclear proteins leave the chromosomes during prophase and prometaphase and return to the nucleus during late telophase. The cells in the matrix and upper bulb of the growing hair follicle and those in the germinal, prickle, and granular cell layers of the tongue are in different functional states; 30 min after injection of 3H-tyrosine they have different amounts of it in their nuclear proteins. It is suggested that the amount incorporated into each nucleus is related to the rate at which proteins are being synthesized by the cell.

scholarly journals Acetylcholinesterase aus Rindererythrozyten. Reinigung und Eigenschaften des mit und ohne Triton X-100 solubilisierten Enzyms / Acetylcholinesterase from Bovine Erythrocytes. Purification and Properties of the En­zyme Solubilized in the Presence and the Absence of Triton X-100

1979 ◽  
Vol 34 (9-10) ◽  
pp. 721-725 ◽  
Author(s):  
Heinz Großmann ◽  
Manfred Liefländer
Keyword(s):  
Amino Acid ◽  
Specific Activity ◽  
Multiple Forms ◽  
Terminal Amino Acid ◽  
Enzyme Preparations ◽  
Purification And Properties ◽  
Solubilized Enzyme ◽  
Terminal Amino ◽  
Triton X ◽  
Bovine Erythrocytes

Abstract Acetylcholinesterase was released from bovine erythrocytes by Triton X-100 treatment and pu­rified by twofold affinity chromatography. The detergentfree enzyme was obtained with a specific activity of 4130 U /mg (303 000-fold purification) and a 25% yield. Alternatively, the commercial available crude enzyme was purified. The latter preparation has an uniform molecular weight (Mr 175 000). The Triton-solubilized enzyme, however, can be resolved after removal of the detergent in eight multiple forms (Mr 175 000 and multiple values), in the presence of Triton there exists only one form (Mr 338 000). The amino acid composition of the two enzyme preparations differs significantly. No differences were observed with respect to other properties: SDS gel electrophore­sis revealed two protein bands (Mr 166 000 and 86 000) with both preparations. The enzyme is a glycoprotein with a pI value of 4.3 and contains strongly bound phosphatidylethanolamine. The N-terminal amino acid has been found to be Glu (or Gin).

Effects of acute cold exposure on muscle amino acid and protein in rats

1982 ◽  
Vol 52 (5) ◽  
pp. 1250-1256 ◽  
Author(s):  
O. L. Smith ◽  
G. Huszar ◽  
S. B. Davidson ◽  
E. Davis
Keyword(s):  
Amino Acid ◽  
Cold Exposure ◽  
Muscle Protein ◽  
Serum Insulin ◽  
Amino Nitrogen ◽  
Streptozotocin Diabetes ◽  
Total Amino Acid ◽  
Protein Breakdown ◽  
Amino Acid Release ◽  
Acid Release

To test the effects of acute cold on muscle amino acid and protein 1) rats were exposed to 4 degrees C for 24 h, functionally hepatectomized (eviscerated) and accumulation in the blood used to indicate changes in amino acid release from the tissues; 2) other rats were left intact, and urinary excretion of 3-methylhistidine (proportional to muscle protein breakdown) determined during cold exposure. In the eviscerated group, cold enhanced loss of total amino acids from the tissues (as alpha-amino nitrogen), but the loss (213 +/- 14.8% of basal in 2 h) was not due to excess alanine (180 +/- 8.5%). By comparison, in fasted rats total amino acid was 182 +/- 12.3, alanine 309 +/- 17.2%. Also, the cold-induced loss resembled the effects of streptozotocin diabetes and depended on a depression by cold of serum insulin (to 35.7 +/- 2.3 muU/ml). Therefore it was prevented when insulin was restored by infusion (40 mU . 100 g-1 . h-1) or by adrenodemedullation before cold exposure. Epinephrine (10 micrograms/100 g sc) depressed insulin in the latter and permitted amino acid release to recur. In intact rats, 3-methylhistidine excretion was unaffected by cold. The results suggest that although cold fails to stimulate alanine synthesis or protein breakdown, it inhibits insulin release sympathetically, thereby diminishing the amount of amino acid incorporated into muscle protein.

scholarly journals Experimental Investigation of Water–Sand Mixed Fluid Initiation and Migration in Porous Skeleton during Water and Sand Inrush

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-18 ◽  
Author(s):  
Xin Yang ◽  
Yong J. Liu ◽  
Ming Xue ◽  
Tian H. Yang ◽  
Bin Yang
Keyword(s):  
Structural Instability ◽  
Sand Particle ◽  
Incipient Motion ◽  
High Concentration ◽  
Sand Mixture ◽  
Porous Skeleton ◽  
Key Factor ◽  
Motion Characteristics ◽  
And Migration ◽  
Mixed Fluid

Water–sand inrush is one of the most serious disasters for mining in China. The evaluation of the occurrence and development of a high-concentration water and sand mixed fluid is an important issue for mining in China. In this study, contraposing to the 3 phases of water–sand inrush, three kinds of experiments are designed for the investigation of initiation, development, and occurrence of the disaster. A new sand–water transport testing system is setup to perform the tests. The results show that there are two key points in the disaster: (1) sand particle incipient motion and (2) porous skeleton structural instability. The incipient motion of sand grains is accompanied with the phenomena of volumetric dilatation and granular fluidization. The critical velocity of the incipient motion of the water–sand mixed fluid is significantly affected by the particle size and external stress. The interaction between water and sand grains is the key factor affecting the motion characteristics of water–sand mixture. When the hydraulic conditions exceed the threshold, the water and sand grains are mutually promoted, and the aquifer skeleton becomes unstable. Furthermore, during the water–sand inrush, the curves of volumetric flow rates of sand and water, respectively, for different samples manifest as two distinct waveforms.

scholarly journals Changes in Whole-Body Amino Acid Metabolism in Response to 2 Weeks of the Very-Low Calorie Diet Are Not Affected by Gender

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1700-1700
Author(s):  
Agata Wierzchowska-McNew ◽  
Mariëlle Engelen ◽  
Kristopher Knoop ◽  
Gabriella Ten Have ◽  
John Thaden
Keyword(s):  
Weight Loss ◽  
Amino Acid ◽  
Acid Metabolism ◽  
Whole Body ◽  
Protein Breakdown ◽  
Restricted Diet ◽  
Very Low Calorie Diet ◽  
Low Calorie ◽  
Low Calorie Diet ◽  
Calorie Diet

Abstract Objectives Very Low-Calorie Diet (VLCD) is an approved method to safely achieve substantial short-term weight loss in obese patients. We previously reported that two weeks of the VLCD maintains whole-body protein and amino acid turnover despite a large reduction in lean body mass. Since the observed effects on body weight (BW) and composition differed between men and women, we hypothesized that the changes in amino acid metabolism in a response to the calorie-restricted diet is gender-specific. Methods 34 morbidly obese adults (BMI: 42 ± 0.9 kg/m2, 10 males and 24 females) underwent a VLCD for 2 weeks consisting of 820 kcal/day and 105-grams protein/day. Before the start of the VLCD (baseline), the whole-body production (WBP) rates of multiple amino acids involved in protein metabolism (e.g., glycine (GLY), glutamine (GLN), phenylalanine (PHE), tyrosine (TYR), and arginine (ARG)) were measured after IV pulse administration of their stable isotopes. Weight loss and body composition by dual-energy X-ray absorptiometry were assessed after 2 weeks of the VLCD. Baseline plasma enrichments were measured by LC-MS/MS. Data are presented as mean ± SE. Statistics are performed by Pearson correlation tests. Results The magnitude of the BW loss after 2 weeks of the VLCD differed between males and females (7.0 ± 0.7 kg vs. 4.1 ± 0.2 kg, P < 0.0001, respectively) with a higher reduction in lean body mass observed in men than women (4.3 ± 0.8 kg vs. 2.7 ± 0.4 kg, P < 0.05). Although, females had significantly reduced baseline WBP of ARG (7.3% vs. 2%, P = 0.0027), GLY (22.8% vs. 3.6%, P < 0.001), and PHE (4.8% vs. 3.1%, P = 0.018) in comparison to men, two weeks of the VLCD had a comparable effect on multiple amino acid WBP in both genders. Suppressed contractile myofibrillar protein breakdown rate was observed in both groups (13% vs. baseline, P = 0.02) with no gender difference in net protein breakdown (PHE to TYR conversion rate). Hence, increased catabolism in men cannot be explained by a different response to the 2 weeks of a calorie-restricted diet. Conclusions Despite gender differences in body weight loss and changes in composition in response to a Very Low-Calorie Diet, changes in whole-body amino acid kinetics are not differently affected in men and women. Funding Sources CTRAL Internal Funds.

Effects of two volatile anesthetics and a volatile convulsant on the excitatory and inhibitory amino acid responses in dissociated CNS neurons of the rat

1991 ◽  
Vol 66 (6) ◽  
pp. 2014-2021 ◽  
Author(s):  
M. Wakamori ◽  
Y. Ikemoto ◽  
N. Akaike
Keyword(s):  
Amino Acid ◽  
Nucleus Tractus Solitarius ◽  
Rank Order ◽  
Volatile Anesthetics ◽  
Hill Coefficient ◽  
Gamma Aminobutyric Acid ◽  
High Concentration ◽  
Patch Clamp Technique ◽  
Excitatory Response ◽  
The Hill

1. Effects of two volatile anesthetics [halothane (Hal) and enflurane (Enf)] and a volatile convulsant [hexafluorodiethyl ether (HFE)] on amino acid-induced membrane currents in neurons dissociated from the nucleus tractus solitarius of the rat were examined. The dissociated neurons were voltage clamped in the whole-cell mode of the patch-clamp technique. All drugs were applied with a microperfusion system, termed the "Y-tube" method. 2. The glutamate (Glu)-induced excitatory response was slightly reduced by both the anesthetics. The responses to three agonists at Glu receptor were depressed by Hal (10(-3) M) in the rank order of quisqualate greater than N-methyl-D-aspartate greater than kainate. HFE slightly increased the Glu response at a high concentration of 2 x 10(-3) M. 3. The gamma-aminobutyric acid (GABA)-induced chloride current (ICl) was enhanced by both anesthetics. The dissociation constant (Kd) for the enhancement was 2.3 x 10(-4) M for Hal and 2.1 x 10(-4) M for Enf, and the Hill coefficient was 1.6 for Hal and 1.5 for Enf. HFE depressed the GABA response with a Kd of 8.7 x 10(-5) M and a Hill coefficient of 0.84. 4. Hal (10(-3) M) and Enf (10(-3) M) decreased the Kd of the GABA concentration-response curve from 3.5 x 10(-6) to 10(-6) and 1.9 x 10(-6) M, respectively, without changing the maximum response or the Hill coefficient (1.5). In the presence of HFE (10(-4) M), the Kd was increased to 1.4 x 10(-5) M and the Hill coefficient was slightly changed to 1.2.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Proteins of the kidney microvillar membrane. Purification and properties of carboxypeptidase P from pig kidneys

1985 ◽  
Vol 229 (1) ◽  
pp. 251-257 ◽  
Author(s):  
S Hedeager-Sørensen ◽  
A J Kenny
Keyword(s):  
Amino Acid ◽  
Horseradish Peroxidase ◽  
Immunoaffinity Chromatography ◽  
Maximum Activity ◽  
Single Step ◽  
Acid Oxidase ◽  
Amino Acid Oxidase ◽  
Purification And Properties ◽  
Triton X ◽  
Polypeptide Chains

Carboxypeptidase P has been purified by immunoaffinity chromatography from pig kidneys. A single-step assay with Z-Pro-Met (where Z represents benzyloxycarbonyl) as substrate was used, methionine being determined by using L-amino acid oxidase and horseradish peroxidase. The enzyme constitutes about 1.5% of the kidney microvillar proteins. Triton X-100-solubilized and papain-released forms of the enzyme were isolated. The former had an apparent subunit Mr of 135 000, and the latter form contained two polypeptide chains of Mr 128 000 and 95 000. The undenatured forms were dimeric proteins. In common with other microvillar hydrolases, carboxypeptidase P was a glycoprotein and each subunit contained one Zn atom. MnCl2 (1 mM) in the assay was necessary for maximum activity; in its absence, 0.5 mM-ZnSO4 produced a limited activation, but was inhibitory at higher concentrations. The Km for Z-Pro-Met, in the presence of MnCl2, was 4.1 mM, and the kcat. for freshly prepared enzyme was 1230 min-1. The enzyme lost activity during storage at −20 degrees C. In a limited survey of peptides, hydrolysis was observed only with substrates containing a proline, alanine or glycine residue in the P1 position, and these included angiotensins II and III. The best substrate in this series was Val-Ala-Ala-Phe.

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