scholarly journals Effect of the He-Ne Laser Radiation on the Reproduction Rate and Protein Synthesis of the Yeast

1984 ◽  
Vol 5 (1) ◽  
pp. 27-33 ◽  
Author(s):  
G. E. Fedoseyeva ◽  
T. I. Karu ◽  
V. S. Letokhov ◽  
V. V. Lobko ◽  
N. A. Pomoshnikova ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Laser Radiation ◽  
Dose Range ◽  
Reproduction Rate ◽  
Maximal Activation ◽  
Endomyces Magnusii ◽  
Lag Period

The reproduction rate and protein synthesis of the yeast-like fungus Endomyces magnusii and yeast Torulopsis sphaerica was studied after the He–Ne laser (λ = 632.8 nm) irradiation. The synthesis of protein in E. magnusii was activated in dose range from 0.42 to 0.84 J/cm2 with maximum at 0.63 J/cm2. In T. sphaerica the maximal activation took place at 0.42 J/cm2. The lag-period was not changed, but the exponential period of the growth was reduced by 1.5 hours for irradiated cells.

Protein and Nucleic Acid Syntheses in Dark-dormant Common Purslane(Portulaca oleracea)Seed

Weed Science ◽  
1978 ◽  
Vol 26 (6) ◽  
pp. 669-672 ◽  
Author(s):  
Bonnie J. Reger ◽  
Ida E. Yates
Keyword(s):  
Protein Synthesis ◽  
Nucleic Acid ◽  
Rna Synthesis ◽  
Acid Synthesis ◽  
Portulaca Oleracea ◽  
Dark Incubation ◽  
Radicle Protrusion ◽  
Lag Period ◽  
Common Purslane ◽  
H Protein

Dark-incubated common purslane(Portulaca oleraceaL.) seed synthesize very little protein and essentially no nucleic acids. Dark-incubated seed incorporate only 14 × 10−3nmoles14C-leucine/mg protein/12-h dark. In contrast, seed exposed to 12-h light following 24-h dark incubation incorporate 365 × 10−3-nmoles14C-leucine/mg protein/12-h light. Once dormancy is broken by exposure of seed to light, initiation of radicle protrusion occurs at 12 h. Protein synthesis gradually increases with time in the light and precedes nucleic acid synthesis which is associated with radicle protrusion. During the 12-h lag period preceding radicle protrusion protein synthesis increases significantly by 3 to 9 h in light, RNA synthesis by 9 h in light, and DNA synthesis by 12 h in light. After 12 h in light,32P can be detected in all nucleic acid fractions, DNA and RNAs.

Regulation of K+ Influx in Barley Roots: Evidence for Direct Control by Internal K+

1977 ◽  
Vol 4 (2) ◽  
pp. 313 ◽  
Author(s):  
ADM Glass
Keyword(s):  
Protein Synthesis ◽  
Cell Division ◽  
Actinomycin D ◽  
Direct Control ◽  
Pretreatment Period ◽  
Rna And Protein Synthesis ◽  
Lag Period ◽  
Limited Protein ◽  
K Concentration ◽  
Gamma Irradiated

Values for plasmalemma influx of K+ into excised barley roots, from solutions containing 0.05 mM KCl plus 0.5 mM CaSO4, were reduced by 50-60% following a 6-h pretreatment period in 50 mM KCl plus 0.05 mM CaSO4 solution. This reduction of influx, associated with increased internal K+ concentration, was independent of DNA, RNA and protein synthesis during the pretreatment period as indicated by its insensitivity to the presence of 5-fluorodeoxyuridine, actinomycin D, cycloheximide, p-fluorophenylalanine or anisomycin in the pretreatment solutions. Roots of plantlets grown from gamma-irradiated barley seeds, which were incapable of under-going cell division and capable of only limited protein synthesis, were nevertheless able to reduce K+ influx values in response to increased internal K+ concentration. The measurement of K+ influx from 0.05 mM KCl solutions following pretreatment periods as short as 15 min in 50 mM KCl gave no evidence of any lag period in the development of reduced influx associated with increased internal K+ status. The above experiments are discussed in terms of a model for the regulation of K+ influx which ascribes a direct 'allosteric' role to internal K+ in controlling influx.

Cycloheximide Inhibition of Cytokinin-dependent Protein Synthesis: Correlation with Betacyanin Synthesis

1983 ◽  
Vol 10 (2) ◽  
pp. 145
Author(s):  
D.C Elliott ◽  
A Koltunow
Keyword(s):  
Protein Synthesis ◽  
Biological Response ◽  
Leucine Incorporation ◽  
Basal Rate ◽  
Dependent Protein ◽  
Lag Period

Cytokinin-dependent betacyanin accumulation in Amaranthus trlcolor half-seedlings (cotyledons plus 5-mm hypocotyls) can be detected after a lag period of about 6 h. A significant (P<O.01) promotion by cytokinin of [3H]leucine incorporation into protein was observed at 5-7 h. It is concluded that the cytokinin-induced biological response was subsequent to or at the same time as the effect on protein synthesis and therefore could be dependent on it, a conclusion that is strengthened by the correlation between the effects of cycloheximide on the two processes. Cycloheximide preferentially inhibits cytokinin-dependent protein synthesis as compared to the effect of the inhibitor on the basal rate.

scholarly journals MACROPHAGE-MELANOMA CELL HETEROKARYONS

1971 ◽  
Vol 134 (4) ◽  
pp. 935-946 ◽  
Author(s):  
Saimon Gordon ◽  
Zanvil Cohn
Keyword(s):  
Protein Synthesis ◽  
Dna Synthesis ◽  
Melanoma Cell ◽  
Melanoma Cells ◽  
Irreversible Inhibitor ◽  
Cell Pretreatment ◽  
Lag Period ◽  
Inhibitor Of Protein Synthesis ◽  
Physical Changes ◽  
The Relationship

Dormant macrophage nuclei initiate DNA synthesis 2–3 hr after fusion of macrophages with exponentially growing melanoma cells. Cycloheximide treatment (1–5 µg/ml) of heterokaryons during the preceding lag period inhibits the initiation of macrophage DNA synthesis, in a reversible fashion. Each type of cell was also treated with streptovitacin A, an irreversible inhibitor of protein synthesis. Pretreatment of the melanoma cells (0.5–2 µg/ml), 1 hr before fusion, inhibited the induction of macrophage DNA synthesis in heterokaryons, whereas pretreatment of macrophages (1–20 µg/ml) had no effect. Melanoma cell pretreatment reduced the incorporation of leucine-3H into the cytoplasm and nuclei of heterokaryons, whereas macrophage pretreatment had no effect. These experiments suggested that melanoma proteins played an important role in the initiation of macrophage DNA synthesis. The relationship between the melanoma cell cycle and macrophage DNA synthesis was studied with synchronous melanoma cells. If the melanoma cells were in S phase at the time of fusion, macrophage DNA synthesis occurred 2 hr later. However, the fusion of melanoma cells in G1 delayed macrophage DNA synthesis until the melanoma nuclei had entered S. Experiments with actinomycin and cycloheximide showed that RNA and protein, essential to achieve DNA synthesis in the macrophage nucleus, were made during late G1 as well as S. Melanoma cells and macrophages differ in their radiolabeled acid-soluble products after incubation in thymidine-3H. Thymidine taken up by the macrophage remained unphosphorylated, whereas it was recovered mainly as thymidine triphosphate from melanoma cells. These findings, as well as those reported previously, suggest that the melanoma cell provides the RNA, protein, and precursors which initiate macrophage DNA synthesis. In the absence of a requirement for new macrophage RNA and protein synthesis, other changes must be responsible for the 2 hr delay in DNA synthesis. These may involve physical changes in DNA, associated with swelling, as well as the transport of melanoma products into the macrophage nucleus.

scholarly journals The action of streptomycin in a mutant of Escherichia coli with increased sensitivity to the antibiotic

1970 ◽  
Vol 118 (4) ◽  
pp. 659-666 ◽  
Author(s):  
G. Turnock
Keyword(s):  
Escherichia Coli ◽  
Protein Synthesis ◽  
Normal Cell ◽  
Permeability Barrier ◽  
Bactericidal Action ◽  
Site Of Action ◽  
Inhibition Of Protein Synthesis ◽  
Increased Sensitivity ◽  
Lag Period

A mutant of Escherichia coli with increased sensitivity to streptomycin has been studied. This strain differed from a normal strs strain in that streptomycin produced inhibition of protein synthesis and loss of viability with almost no lag period. Chloramphenicol protected a normal strs strain but not the mutant against the bactericidal action of streptomycin. The results obtained support the idea that access of streptomycin to its site of action in a normal cell is restricted, and that this restriction, which is much less effective in the mutant, probably involves a permeability barrier. Comparison of the inhibition of protein synthesis by streptomycin with concomitant changes in the distribution of polyribosomes in both strains suggested that the antibiotic can directly inhibit the translation of mRNA.

scholarly journals Evidence for the glia-neuron protein transfer hypothesis from intracellular perfusion studies of squid giant axons.

1977 ◽  
Vol 74 (2) ◽  
pp. 524-530 ◽  
Author(s):  
H Gainer ◽  
I Tasaki ◽  
R J Lasek
Keyword(s):  
Protein Synthesis ◽  
Action Potentials ◽  
De Novo ◽  
Protein Transfer ◽  
Intracellular Perfusion ◽  
Giant Axons ◽  
Perfusion Studies ◽  
Time Period ◽  
Lag Period ◽  
De Novo Protein Synthesis

Incubation of intracellulary perfused squid giant axons in [3H]leucine demonstrated that newly synthesized proteins appeared in the perfusate after a 45-min lag period. The transfer of labeled proteins was shown to occur steadily over 8 h of incubation, in the presence of an intact axonal plasma membrane as evidenced by the ability of the perfused axon to conduct propagated action potentials over this time-period. Intracellularly perfused RNase did not affect this transfer, whereas extracellularly applied puromycin, which blocked de novo protein synthesis in the glial sheath, prevented the appearance of labeled proteins in the perfusate. The uptake of exogenous 14C-labeled bovine serum albumin (BSA) into the axon had entirely different kinetics than the endogenous glial labeled protein transfer process. The data provide support for the glia-neuron protein transfer hypothesis.

Derepression of Arylsulfatase Activity by Sulfate Starvation in Chlorella fusca

1987 ◽  
Vol 42 (5) ◽  
pp. 530-536 ◽  
Author(s):  
Inge Niedermeyer ◽  
Susanne Biedlingmaier ◽  
Ahlert Schmidt
Keyword(s):  
Protein Synthesis ◽  
Boric Acid ◽  
Limiting Factor ◽  
Type I ◽  
Chlorella Fusca ◽  
Sulfur Starvation ◽  
Arylsulfatase Activity ◽  
Green Alga Chlorella ◽  
Lag Period ◽  
Starvation Conditions

Abstract Arylsulfatase activity was detected in the green alga Chlorella fusca 211-8b during sulfur starvation. No activity was present during growth on sulfate, whereas activity was found with sulfur sources as growth-limiting factor including L-cysteine and L-methionine. Arylsulfatase activity was found after transfer to sulfate starvation conditions after a lag-period of about 3 h; addition of cycloheximide prevented arylsulfatase formation, suggesting the participation of protein synthe­ sis. Addition of sulfate to cultures with active arylsulfatase led to a decay of this enzyme, whereas addition of sulfate and cycloheximide prevented this decay suggesting that protein synthesis is also needed for degradation of arylsulfatase activity. The Km for p-nitrophenyl sulfate was determined to be 0.8 mм. The activity of the arylsulfatase is not affected by sulfate or phosphate, however it is inhibited strongly by sulfite, cyanide and boric acid and therefore is classified according to Dogson and Spencer (Meth. Biochem. Anal. 4, 211-254 (1957) as an arylsulfatase of type I.

Zoospore Germination in Blastocladiella Emersonii

1971 ◽  
Vol 9 (3) ◽  
pp. 679-699
Author(s):  
D. R. SOLL ◽  
D. R. SONNEBORN
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Actinomycin D ◽  
Morphological Changes ◽  
Amino Acid Incorporation ◽  
Population Kinetics ◽  
Turn On ◽  
Acid Incorporation ◽  
Lag Period ◽  
Flagellar Axoneme

1. Zoospores germinate rapidly and semi-synchronously upon exposure to growth medium or an inorganic salts solution. Amino acid incorporation into protein is detected only after a characteristic lag period, the extent of which is a function of developmental, rather than absolute, time. 2. The ‘turn-on’ of amino acid incorporation occurs after several of the morphological events of germination have taken place - notably, retraction of the flagellum, conversion to a spheroid cell morphology, vesicle fusion with the plasma membrane, formation of the initial cell wall, and elongation of the single mitochondrion. A second group of morphological changes - release of ribosomes from the nuclear cap into the cytoplasm, appearance of multiple mitochondrial profiles, disappearance of the flagellar axoneme, and disappearance of gamma particles - takes place in the cell population during the turn-on of incorporation. 3. Cycloheximide reversibly inhibits germination at a characteristic block point. Inhibited cells accomplish all the known morphological events of germination except the disappearance of the flagellar axoneme and the formation of the germ tube. Amino acid incorporation is inhibited to undetectable levels in growth medium and by about 80% in the inorganic salts medium. Nevertheless, the population kinetics for the morphological changes which occur in cycloheximide-inhibited cells are indistinguishable from those in untreated cells. Cycloheximide effectively enters cells prior to the characteristic block point, since the drug drastically inhibits the low level of amino acid incorporation by zoospores. 4. ‘Pools’ extractable by trichloroacetic acid (TCA) have been examined; the results do not support the possibility of extensive early protein synthesis from endogenous sources. 5. Actinomycin D, at levels which inhibit [3H]uridine incorporation into TCA-precipitable material (nucleic acid) by over 98%, does not affect the population kinetics of germination. The drug does not affect the lag period for amino acid incorporation. The rate of amino acid incorporation (pulse labelling) fluctuates predictably during germination. Actinomycin D only partially inhibits the first ‘round’ of incorporation, but severely inhibits the second. From this information, we conclude that: (a) the proteins necessary for most of the structural events of germination are preformed in the zoospore; (b) therefore, these events are controlled directly by mechanisms other than differential protein synthesis; (c) two of the known events - disappearance of the flagellar axoneme and formation of the germ tube - do appear to have a requirement for concomitant protein synthesis; (d) germination does not require de novo RNA synthesis; and (e) certain of the first proteins made during germination are evidently synthesized with preformed messages.

scholarly journals The cellular origin of glyoxysomal proteins in germinating castor-bean endosperm

1976 ◽  
Vol 154 (2) ◽  
pp. 501-506 ◽  
Author(s):  
L Bowden ◽  
J. M Lord
Keyword(s):  
Endoplasmic Reticulum ◽  
Protein Synthesis ◽  
Castor Bean ◽  
Developmental Stages ◽  
Endoplasmic Reticulum Membrane ◽  
Endosperm Tissue ◽  
Cellular Origin ◽  
Lag Period ◽  
Kinetics Of

The capacity of castor-bean endosperm tissue to incorporate [35S]methionine into proteins of the total particulate fraction increased during the first 3 days of germination and subsequently declined. At the onset of germination 66% of the incorporated 35S was found in the separated endoplasmic-reticulum fraction, with the remainder in mitochondria, whereas at later developmental stages an increasing proportion of 35S was recovered in glyoxysomes. The kinetics of [35S]methionine incorporation into the major organelle fractions of 3-day-old endosperm tissue showed that the endoplasmic reticulum was immediately labelled, whereas a lag period preceded the labelling of mitochondria and glyoxysomes. When kinetic experiments were interrupted by the addition of an excess of unlabelled methionine, incorporation of [35S]methionine into the endoplasmic reticulum rapidly ceased, but incorporation into mitochondia and glyoxysomes continued for a further 1h. Examination of isolated organelle membranes during this period showed that the addition of unlabelled methionine resulted in a stimulated incorporation of [35S]no methionine into the endoplasmic-reticulum membrane for 30 min, after which time the 35S content of this fraction declined, whereas that of the glyoxysomal membranes continued to increase slowly. The 35S-labelling kinetics of organelles and fractions derived therefrom are discussed in relation to the role of the endoplasmic reticulum in protein synthesis during glyoxysome biogenesis.

scholarly journals Insulin and glucagon attenuate the ability of cholera toxin to activate adenylate cyclase in intact hepatocytes

1988 ◽  
Vol 251 (2) ◽  
pp. 447-452 ◽  
Author(s):  
F J Irvine ◽  
M D Houslay
Keyword(s):  
Adenylate Cyclase ◽  
Cholera Toxin ◽  
Regulatory Protein ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Stimulatory Action ◽  
Maximal Activation ◽  
Lag Period ◽  
Guanine Nucleotide Regulatory Protein ◽  
Dose Dependent

Treatment of intact hepatocytes with cholera toxin at 37 degrees C caused a stable activation of adenylate cyclase activity after a lag period of around 10 min. The presence of either insulin (10 nM) or glucagon (10 nM) in the incubation medium had little effect on this lag period; however, these hormones markedly attenuated the maximal activation of adenylate cyclase activity that could be achieved by treatment with cholera toxin. Such actions of insulin and glucagon were dose-dependent, with EC50 values (concn. giving 50% inhibition) of 0.20 nM for insulin and 0.49 nM for glucagon, and were not additive. Treatment of intact hepatocytes with either glucagon or insulin did not affect the ability of cholera toxin to cause the ADP-ribosylation of the 45 kDa alpha-subunit of the stimulatory guanine nucleotide regulatory protein, Gs, in intact hepatocytes. It is suggested that treatment of intact hepatocytes with either insulin or glucagon attenuates the stimulatory action of ADP-ribosylated Gs on adenylate cyclase.

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