Neurotrophic dependence of macromolecular synthesis in the early limb regenerate of the newt, Triturus

Development ◽  
1972 ◽  
Vol 28 (1) ◽  
pp. 1-11
Author(s):  
Marcus Singer ◽  
J. Douglas Caston
Keyword(s):  
Intraperitoneal Injection ◽  
Specific Activity ◽  
Limb Regeneration ◽  
Macromolecular Synthesis ◽  
Previous Demonstration ◽  
Rna And Dna

The well-documented nerve dependence of limb regeneration in the newt was analysed by study of accumulation of newly synthesized macromolecules following denervation. The specific activity of RNA and DNA in the denervated early regenerate bud was determined following intraperitoneal injection of [3H]-uridine and [3H]-thymidine. Results showed an outburst in the incorporation into RNA and DNA which reached a peak 3 h after denervation for the former and 7 h for the latter. There was then a decline in incorporation to a plateau about 50–60% of the control non-denervated side within 48 h. Combining these results with our previous demonstration of a similar outburst in the accumulation of newly synthesized protein with a peak at 4 h, the sequence of the outbursts was in order RNA, protein and DNA. The results are interpreted to mean that the nerve influences either macromolecular synthesis or macromolecular processing and turnover, and therefore accumulation in the regenerate.

DIE INITIALE VERTEILUNG VON RADIO-C IN DEN ZELLFRAKTIONEN EINIGER RATTENORGANE NACH INJEKTION VON TESTOSTERON-4-14C

1964 ◽  
Vol 47 (1) ◽  
pp. 51-57 ◽  
Author(s):  
K.-O. Mosebach ◽  
W. Dirscherl
Keyword(s):  
Intraperitoneal Injection ◽  
Specific Activity ◽  
Initial Distribution ◽  
Male Rats ◽  
Initial Formation ◽  
Thigh Muscles ◽  
The Absolute ◽  
Cell Fractions

ABSTRACT The initial distribution of radioactive C was studied in the cell fractions of the liver, kidney, testes and thigh muscles after intraperitoneal injection of testosterone-4-14C into 40 day old male rats. To make this possible, the absolute and specific activity values (μc/mg C) were determined. After both ten and twenty minutes the cytoplasm fractions possessed the highest activity values, the only exception being the specific activity of the liver cytoplasm ten minutes after injection when the microsomes of the liver showed a higher activity. After 20 min the mitochondria possessed the highest specific activity values among the corpuscular fractions. The specific activity values in the microsomes of all four organs studied were lower 20 min after the time of injection than after 10 min, a fact, which is suspected to be the result of the initial formation of conjugates in the microsomes.

PHOSPHORUS METABOLISM OF THE LIVER: EFFECT OF HYPOPHYSECTOMY, ADRENALECTOMY, AND ADMINISTRATIONOF ACTH ON THE INCORPORATION OF RADIOACTIVE PHOSPHATE INTO RNA NUCLEOTIDES

1955 ◽  
Vol 33 (1) ◽  
pp. 54-61 ◽  
Author(s):  
J. E. Logan ◽  
F. C. Heagy ◽  
R. J. Rossiter
Keyword(s):  
Adrenal Cortex ◽  
Intraperitoneal Injection ◽  
Inorganic Phosphate ◽  
Adrenal Glands ◽  
Specific Activity ◽  
Phosphorus Metabolism ◽  
Relative Specific Activity ◽  
Hypophysectomized Rats

The specific activity of the liver RNA nucleotide phosphorus, relative to the specific activity of the liver inorganic phosphate, was determined in the rat, 16 hr. after an intraperitoneal injection of radioactive inorganic phosphate. The nucleotides were isolated by ionophoresis on paper strips.Hypophysectomy caused a decrease in the relative specific activity of each of the four RNA nucleotides. The administration of ACTH caused an increase in the incorporation of P32 into each of the RNA nucleotides of the liver of hypophysectomized animals, but it caused a small and statistically significant decrease in normal animals. Adrenalectomy, either in normal or in hypophysectomized rats, did not affect the P32 incorporation, nor did the administration of ACTH in the absence of the adrenal glands.It is concluded that ACTH can affect the incorporation of P32 into the RNA of the liver and that this effect is due to the action of the hormone on the adrenal cortex. However, other factors also must be operative, since removal of the adrenal glands does not cause the decrease in the P32 incorporation observed after removal of the pituitary.

scholarly journals Similarities between the biochemical actions of cycasin and dimethylnitrosamine

1967 ◽  
Vol 105 (2) ◽  
pp. 521-527 ◽  
Author(s):  
R. C. Shank ◽  
P. N. Magee
Keyword(s):  
Small Intestine ◽  
Ion Exchange ◽  
Active Compound ◽  
Intraperitoneal Injection ◽  
Leucine Incorporation ◽  
Stomach Tube ◽  
Purine Base ◽  
Acetate Ester ◽  
Ion Exchange Column ◽  
Rna And Dna

1. Rats were given the hepatotoxin and carcinogen cycasin by stomach tube. In one experiment, rats whose RNA had previously been labelled with [14C]-formate were given the acetate ester of the aglycone form of cycasin, methylazoxymethanol, by intraperitoneal injection. 2. Incorporation of 14C from l-[U−14C]leucine into the proteins of some organs was measured in cycasin-treated rats. Cycasin inhibited leucine incorporation into liver proteins but not into kidney, spleen or ileum proteins. This inhibition was not evident until about 5hr. after cycasin administration, but once established it persisted for the next 20hr. 3. Methylation of nucleic acids was detected in some organs of rats treated with cycasin or methylazoxymethanol. The purine bases of RNA and DNA were isolated by acid hydrolysis followed by ion-exchange column chromatography. The resulting chromatograms showed an additional purine base that was identified as 7-methylguanine. It was shown that, in animals treated with the toxin, liver RNA was methylated to a greater extent than was either kidney or small-intestine RNA. Also, as a result of cycasin administration, liver DNA guanine was methylated to a greater extent than was RNA guanine. 4. These results are discussed in relation to comparable experiments with dimethylnitrosamine. It is suggested that cycasin and dimethylnitrosamine are metabolized to the same biochemically active compound, perhaps diazomethane, but that various tissues differ in their capacity to metabolize the two carcinogens.

scholarly journals THE MECHANISM OF COLCHICINE INHIBITION OF MITOSIS

1965 ◽  
Vol 25 (1) ◽  
pp. 145-160 ◽  
Author(s):  
Edwin W. Taylor
Keyword(s):  
Cell Cycle ◽  
Mitotic Spindle ◽  
Specific Activity ◽  
High Specific Activity ◽  
Quantitative Agreement ◽  
Direct Effects ◽  
Macromolecular Synthesis ◽  
Reversible Binding ◽  
Maximum Value ◽  
Interphase Cells

H3-colchicine of high specific activity (2.5 curies per mM) was prepared in order to study the mechanism of colchicine inhibition of mitosis in cultures of human cells, strain K.B. No direct effects on the duration of the cell cycle or macromolecular synthesis were demonstrable at a concentration of colchicine which completely inhibited mitosis. The radioactive compound was bound to the cells at a rate proportional to colchicine concentration. The binding appeared to be reversible since the radioactivity of the cells reached a maximum value for a given concentration and was slowly lost after resuspension of the cells in fresh medium. A suitable exposure to colchicine produced accumulation of metaphase-blocked mitoses after the colchicine was removed from the medium. An exposure of 6 to 8 hours at 10-7 M was sufficient to block essentially all the cells in metaphase, thus indicating that colchicine is bound to the majority of interphase cells. The data are in quantitative agreement with a mechanism involving reversible binding of colchicine to a set of cellular sites. Based on the correlation between the time of first appearance of blocked mitoses and the radioactivity per cell, it is suggested that if a critical fraction (3 to 5 per cent) of the sites are complexed, the cell is unable to form a functional mitotic spindle.

PHOSPHORUS METABOLISM OF THE LIVER: EFFECT OF HYPOPHYSECTOMY, ADRENALECTOMY, AND ADMINISTRATIONOF ACTH ON THE INCORPORATION OF RADIOACTIVE PHOSPHATE INTO RNA NUCLEOTIDES

1955 ◽  
Vol 33 (1) ◽  
pp. 54-61
Author(s):  
J. E. Logan ◽  
F. C. Heagy ◽  
R. J. Rossiter
Keyword(s):  
Adrenal Cortex ◽  
Intraperitoneal Injection ◽  
Inorganic Phosphate ◽  
Adrenal Glands ◽  
Specific Activity ◽  
Phosphorus Metabolism ◽  
Relative Specific Activity ◽  
Hypophysectomized Rats

The specific activity of the liver RNA nucleotide phosphorus, relative to the specific activity of the liver inorganic phosphate, was determined in the rat, 16 hr. after an intraperitoneal injection of radioactive inorganic phosphate. The nucleotides were isolated by ionophoresis on paper strips.Hypophysectomy caused a decrease in the relative specific activity of each of the four RNA nucleotides. The administration of ACTH caused an increase in the incorporation of P32 into each of the RNA nucleotides of the liver of hypophysectomized animals, but it caused a small and statistically significant decrease in normal animals. Adrenalectomy, either in normal or in hypophysectomized rats, did not affect the P32 incorporation, nor did the administration of ACTH in the absence of the adrenal glands.It is concluded that ACTH can affect the incorporation of P32 into the RNA of the liver and that this effect is due to the action of the hormone on the adrenal cortex. However, other factors also must be operative, since removal of the adrenal glands does not cause the decrease in the P32 incorporation observed after removal of the pituitary.

scholarly journals Preparation and Purification of Tritiated Phytohemagglutinin and Studies of Cellular Localization in Human Leukocyte Cultures

Blood ◽  
1970 ◽  
Vol 35 (1) ◽  
pp. 44-55 ◽  
Author(s):  
ROBERT A. CONARD ◽  
CHARLES F. DEMOISE
Keyword(s):  
Cellular Localization ◽  
Mononuclear Cells ◽  
Specific Activity ◽  
Specific Radioactivity ◽  
Human Leukocyte ◽  
Chemical Extraction ◽  
Mitochondrial Activity ◽  
Electron Microscopic ◽  
Grain Distribution ◽  
Rna And Dna

Abstract A tritiated bean extract was obtained from bean plants (Phaseolus vulgaris) grown hydroponically in nutrient media containing various concentrations of tritium water. Purification was accomplished by ammonium sulfate precipitation and column chromatography using DEAE, CM-52 cellulose columns, and finally by Sephadex G-100 gel filtration. The purified product showed greatly increased mitogenic activity and electrophoretically showed a single labeled protein band on electrophoresis. Radioactivity of the purified PHA varied between 0.1-0.5 µCi/mg. which, though not as high as desirable, was sufficient for autoradiographic and subcellular fractionation studies in human leukocyte cultures. Within a few hours cytoplasmic localization of the label was noted in most of the cells in culture, including neutrophils and larger mononuclear cells. Breakdown of many of these cells during the first 24 hr. resulted in labeled amorphous basophilic staining masses of cell particles. Though agglutination of cells was commonly seen, the lack of label in red cells or surface label of leukocytes was notable. Blast forms which appeared by the second day showed prominent labeling which appeared to be largely cytoplasmic as evidenced by grain distribution. Several reasons were discussed which made it seem likely that the mitogenic molecule was represented in the cell label. Assay of subcellular fractions showed the major portion of radioactivity in the mitochondrial fraction. Specific activity, however, was too low to permit electron microscopic localization of label in individual organelles. Lack of label of RNA and DNA proteins was demonstrated by cellular distribution of the label and chemical extraction of RNA and DNA. Interesting speculation arises as to whether the PHA may stimulate mitochondrial activity and induce RNA synthesis and blastogenesis. Further experiments are in progress to obtain a purer PHA with higher specific radioactivity in order to more precisely define the site and mechanism of action of the mitogen.

Radioiodination of Alginate via Covalently-Bound Tyrosinamide Allows Monitoring of its Fate In Vivo

1995 ◽  
Vol 10 (1) ◽  
pp. 4-13 ◽  
Author(s):  
Aymen Al-Shamkhani ◽  
Ruth Duncan
Keyword(s):  
Molecular Weight ◽  
Intraperitoneal Injection ◽  
Specific Activity ◽  
Subcutaneous Administration ◽  
High Specific Activity ◽  
Weight Fraction ◽  
Low Molecular Weight ◽  
Blood Compartment ◽  
Almost All

Tb monitor the fate of alginate following systemic administration, a method was developed that allowed the covalent incorporation of approximately 1 mol% tyrosinamide. The product could be radioiodinated to a high specific activity, and was subsequently stable on storage at 4°C for 30 days, with very little (c 1%) free [125I] iodide released over that period. Twenty-four hours following intravenous administration, the low molecular weight fraction (<48,000) of the injected polymer was excreted in the urine while the larger polymer fraction remained in the circulation and did not readily accumulate in any of the tissues. Almost all of the dose administered by intraperitoneal injection was transferred from the peritoneal cavity to the blood compartment within 24 h, with the low molecular weight fraction of the polymer excreted in the urine. Following subcutaneous administration, the majority (-70%) of the injected dose was retained at the site of injection at 24 h.

Determination of fractional disappearance rate of kidney cholesterol

1963 ◽  
Vol 204 (3) ◽  
pp. 505-508 ◽  
Author(s):  
Charles H. Duncan ◽  
Maurice M. Best
Keyword(s):  
Rate Constant ◽  
Intraperitoneal Injection ◽  
Specific Activity ◽  
Left Kidney ◽  
Mevalonic Acid ◽  
Disappearance Rate ◽  
Selective Labeling ◽  
Additional Group ◽  
Back Exchange

Mevalonic acid-2-C14 was injected intraperitoneally into rats, and the incorporation of the C14 into cholesterol of various tissues determined. A disproportionate incorporation into kidney cholesterol was observed, resulting in a specific activity 55 times that of serum cholesterol with which it can exchange. This selective labeling of kidney cholesterol and the essentially identical cholesterol-C14 content found in the two kidneys permitted the determination of the disappearance rate constant of kidney cholesterol without the necessity of considering back exchange of the label. One week after the intraperitoneal injection of mevalonic acid-2-C14 into an additional group of rats the left kidney was removed from each animal and its cholesterol-C14 content determined; from 2 to 6 weeks later the remaining kidney was removed and its cholesterol-C14 content also determined. A disappearance rate constant of the labeled kidney cholesterol of 0.030 day–1 was found.

PHOSPHORUS METABOLISM OF THE ADRENAL GLAND EFFECT OF HYPOPHYSECTOMY AND ADMINISTRATION OF ACTH ON INCORPORATION OF P32 INTO INORGANIC PHOSPHATE

1954 ◽  
Vol 32 (3) ◽  
pp. 251-260 ◽  
Author(s):  
B. E. Riedel ◽  
J. E. Logan ◽  
H. A. DeLuca ◽  
R. J. Rossiter
Keyword(s):  
Adrenal Gland ◽  
Intraperitoneal Injection ◽  
Inorganic Phosphate ◽  
Specific Activity ◽  
Time Intervals ◽  
Inorganic P ◽  
Relative Specific Activity ◽  
Single Intraperitoneal Injection ◽  
Hypophysectomized Rats ◽  
Significant Change

In confirmation of the work of others, the concentration of inorganic phosphate (P) in the plasma of hypophysectomized rats was found to be less than that in the plasma of control animals. Hypophysectomy caused no significant change in the concentration of inorganic P in the adrenal gland or liver. A single intraperitoneal injection of each of two preparations of ACTH failed to cause any significant change in the concentrations of inorganic P in plasma, adrenal, or liver.The specific activity of the inorganic P in the plasma of hypophysectomized rats after an intraperitoneal injection of inorganic P labelled with P32 was greater than that in the control animals. Hypophysectomy caused a decrease in the specific activity of the inorganic P of the adrenal gland relative to that of the inorganic P of the plasma. Each of the two preparations of ACTH, given to the hypophysectomized animals as a single intraperitoneal injection 20 hr. before killing, restored the relative specific activity of the inorganic P of the adrenals to normal values. When the ACTH was administered six hours before killing, one of the preparations (ACTH A) caused an increase in the relative specific activity of the inorganic P of the adrenals, but a second preparation (ACTH C) was without significant effect.The increase in the specific activity of the inorganic P of the plasma comes on slowly (quite small two days after hypophysectomy), whereas the decrease in the relative specific activity of the inorganic P of the adrenal gland comes on rapidly (maximal two days after hypophysectomy). For this reason, at longer time intervals after hypophysectomy (greater than six days) the absolute activity of the acid-soluble P of the adrenal, i.e. the activity not referred to that of the inorganic P of the plasma, was greater in hypophysectomized animals, and not less, as reported by other workers. The activity of this fraction is less in hypophysectomized animals only if the observations are made at short time intervals after removal of the pituitary. Evidence is presented for the view that the increase in the specific activity of the inorganic P of the plasma is the result of changes brought about by a deficiency of growth hormone, whereas the decrease in the relative specific activity of the adrenal is due to a deficiency of ACTH.

Participation of cartilage grafts in amphibian limb regeneration

Development ◽  
1974 ◽  
Vol 32 (2) ◽  
pp. 391-404
Author(s):  
H. Wallace ◽  
M. Maden ◽  
B. M. Wallace
Keyword(s):  
Connective Tissue ◽  
Blood Vessels ◽  
Limb Regeneration ◽  
Host Cells ◽  
Variable Response ◽  
Cartilage Grafts ◽  
Mesenchyme Cells ◽  
Previous Demonstration

Irradiated axolotl arms bearing grafts of pure cartilage obtained from the non-irradiated humerus of other specimens show a variable response to amputation of the hand. Some arms grow spikes with little morphogenesis, others produce one or more digits, and some regenerate small and defective but recognizable hands. Identically irradiated control arms which carry no grafts or grafts of irradiated tissue show none of these features. The cartilage grafts must therefore be responsible for the limited amount of regeneration observed. The origin of the regenerated tissues could not be independently determined in this experiment, although grafts were made reciprocally between white and dark genotypes, as all the regenerates were either very pale or completely unpigmented. A previous demonstration that grafted tissue does not reactivate irradiated host cells, however, permits the conclusion that the grafted cartilage provides all the mesodermal tissues of these regenerates. The grafts consisted exclusively of chondrocytes, while the regenerates contained cartilage, muscle, blood vessels, nerve sheaths and general connective tissue. It is concluded that chondrocytes dedifferentiate into pluripotent blastemal mesenchyme cells which can redifferentiate into all other internal tissues of the limb. The concepts of modulation and neoblasts (undifferentiated reserve cells) thus have no basis in amphibian limb regeneration.

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