Evidence that elevated intracellular cyclic AMP maturation in Dictyostelium

Development ◽  
1989 ◽  
Vol 105 (4) ◽  
pp. 753-759 ◽  
Author(s):  
R.R. Kay
Keyword(s):  
Cyclic Amp ◽  
Fruiting Body ◽  
Normal Development ◽  
Environmental Influences ◽  
Intracellular Camp ◽  
Spore Coat ◽  
Transduction Pathway ◽  
Wild Type ◽  
Type Strains ◽  
Spore Maturation

Spore maturation occurs during normal development in when environmental influences induce a migrating slug a fruiting body. As the amoeboid prespore cells turn spores there is a burst of enzyme accumulation, epimerase, and at a later stage the exocytosis of of the spore coat. Evidence is presented here that triggered by an elevated intracellular cAMP number of rapidly developing (rde) mutants, whose cAMP been investigated previously, are shown to be able to submerged monolayers, whereas wild-type strains are of these mutants are best explained by a derepression transduction pathway utilizing intracellular cAMP. direct, it is shown that the permeant cAMP analogues

scholarly journals Overexpression of an activated rasG gene during growth blocks the initiation of Dictyostelium development.

1996 ◽  
Vol 16 (8) ◽  
pp. 4156-4162 ◽  
Author(s):  
M Khosla ◽  
G B Spiegelman ◽  
G Weeks
Keyword(s):  
Growth Rate ◽  
Cell Growth ◽  
Cyclic Amp ◽  
Dominant Negative ◽  
Differentiation Process ◽  
Fruiting Bodies ◽  
Wild Type ◽  
Ras Protein ◽  
Initial Generation ◽  
Type Strains

Transformants that expressed either the wild-type rasG gene, an activated rasG-G12T gene, or a dominant negative rasG-S17N gene, all under the control of the folate-repressible discoidin (dis1gamma) promoter, were isolated. All three transformants expressed high levels of Ras protein which were reduced by growth in the presence of folate. All three transformants grew slowly, and the reduction in growth rate correlated with the amount of RasG protein produced, suggesting that RasG is important in regulating cell growth. The pVEII-rasG transformant containing the wild-type rasG gene developed normally despite the presence of high levels of RasG throughout development. This result indicates that the down regulation of rasG that normally occurs during aggregation of wild-type strains is not essential for the differentiation process. Dictyostelium transformants expressing the dominant negative rasG-S17N gene also differentiated normally. Dictyostelium transformants that overexpressed the activated rasG-G12T gene did not aggregate. The defect occurred very early in development, since the expression of car1 and pde, genes that are normally induced soon after the initiation of development, was repressed. However, when the transformant cells were pulsed with cyclic AMP, expression of both genes returned to wild-type levels. The transformants exhibited chemotaxis to cyclic AMP, and development was synergized by mixing with wild-type cells. Furthermore, cells that were pulsed with cyclic AMP for 4 h before being induced to differentiate by plating on filters produced small, but otherwise normal, fruiting bodies. These results suggest that the rasG-G12T transformants are defective in cyclic AMP production and that RasG - GTP blocks development by interfering with the initial generation of cyclic AMP pulses.

scholarly journals Cyclic nucleotides in glutamate chemosensory signal transduction of Paramecium

1997 ◽  
Vol 110 (20) ◽  
pp. 2567-2572
Author(s):  
W.Q. Yang ◽  
C. Braun ◽  
H. Plattner ◽  
J. Purvee ◽  
J.L. Van Houten
Keyword(s):  
Signal Transduction ◽  
Cyclic Amp ◽  
Cyclic Gmp ◽  
Signal Transduction Pathway ◽  
Protein Kinase Inhibitors ◽  
Intracellular Camp ◽  
Paramecium Tetraurelia ◽  
Transduction Pathway ◽  
Kinetic Measurements ◽  
Chemosensory Transduction

Glutamate is an attractant stimulus to Paramecium tetraurelia. It causes a hyperpolarization of the cell and smooth, relatively fast swimming that is characteristic of hyperpolarizing stimuli. We show here that by 1–30 seconds of stimulation, glutamate increases intracellular cAMP. Interestingly, other attractant stimuli, such as acetate and NH4Cl, that similarly hyperpolarize the cell do not induce an increase in cyclic AMP observable at 30 seconds. In order to determine whether the changes in cyclic AMP could be rapid enough to participate in stimulation as compared to slower processes such as adaptation, rapid kinetic measurements of cyclic AMP were made on whole cells by quenched-flow. We found that, in cells stimulated with glutamate, intracellular cyclic AMP increases by 30 mseconds and peaks at about sevenfold over basal levels by 200 mseconds. Cyclic GMP does not change relative to basal levels over rapid or slower time courses of glutamate stimulation. An antagonist of glutamate, IMP, depolarizes the cells and decreases intracellular cyclic AMP by approx. 50% and slightly increases cyclic GMP. Results of behavioral tests of cells treated with protein kinase inhibitors also suggest that cyclic AMP is part of the signal transduction pathway for glutamate, but not for other attractant stimuli. These studies are the first demonstration of a possible role for cyclic nucleotide second messengers in an attractant chemosensory transduction pathway in Paramecium.

Modulating action of cyclic AMP on the expression of two SOS genes in Escherichia coli K-12

1987 ◽  
Vol 33 (8) ◽  
pp. 704-708 ◽  
Author(s):  
Jordi Barbé ◽  
Isidre Gibert ◽  
Ricardo Guerrero
Keyword(s):  
Escherichia Coli ◽  
Cyclic Amp ◽  
Type Strain ◽  
Wild Type Strain ◽  
Wild Type ◽  
Cultural Conditions ◽  
Gene Coding ◽  
K 12 ◽  
Type Strains ◽  
Lambda Prophage

Ultraviolet irradiation and cyclic AMP treatment produce a synergistic effect on the induction of the clel gene (coding for bacteriocin ColE1) in wild-type strains of Escherichia coli. On the other hand, cyclic AMP does not affect the uv-mediated induction of the recA, sfiA, and umuDC genes. Growth in the presence of glucose or glycerol does not affect the factor of amplification of the expression of the clel gene in uv-irradiated cells of the wild-type strain. Although, in cultures not treated with uv, the basal level of clel induction is about twice as high in cells grown with glycerol as in those using glucose as carbon source. In recA mutants neither simultaneous nor separate treatments with either cyclic AMP or uv irradiation induced transcription of the clel gene. Moreover, cyclic AMP induced a slight increase in clel gene expression in uv-irradiated cya strains, but not in the crp mutants. Nevertheless, the pattern of the uv-mediated induction of other SOS genes, such as umuDC, was the same in the cya and crp mutants, as in their parental wild-type strains. Furthermore, the uv-mediated induction of lambda prophage was decreased after either addition of cyclic AMP or growth in cultural conditions where the level of this nucleotide was low.

scholarly journals Dunce mutants of Drosophila melanogaster: mutants defective in the cyclic AMP phosphodiesterase enzyme system.

1981 ◽  
Vol 90 (1) ◽  
pp. 101-107 ◽  
Author(s):  
R L Davis ◽  
J A Kiger
Keyword(s):  
Enzyme Activity ◽  
Drosophila Melanogaster ◽  
Cyclic Amp ◽  
Enzyme System ◽  
Residual Enzyme Activity ◽  
Wild Type ◽  
Camp Content ◽  
Mutant Strains ◽  
Normal Enzyme ◽  
Type Strains

The cyclic AMP and cyclic GMP phosphodiesterase activities present in flies of six mutant strains of the dunce gene and in the parent wild-type strains are characterized. All of the mutants exhibit aberrant cyclic AMP metabolism. The mutant strains dunceM14, dunceM11, and dunceML appear to be amorphic, because they completely lack the cAMP-specific phosphodiesterase normally present in adult flies. These strains exhibit extremely high levels of cAMP. The mutant strains dunce1, dunce2, and dunceCK are hypomorphic and exhibit reduced levels of the cAMP-specific phosphodiesterase. These strains exhibit less marked increases in cAMP content compared with the three amorphic strains. The dunce2 strain possesses a residual enzyme activity that exhibits anomalous kinetics compared with those of the normal enzyme. The possibility that the dunce locus is the structural gene for the cAMP-specific phosphodiesterase is discussed.

Differentiation in roller tube cultures of wild-type and two cyclic AMP mutant strains of the cellular slime mould Polysphondylium pallidum

1982 ◽  
Vol 28 (10) ◽  
pp. 1143-1149
Author(s):  
Gary D. Paterno ◽  
Danton H. O'Day
Keyword(s):  
Cyclic Amp ◽  
Fruiting Body ◽  
Weight Fraction ◽  
Stalk Cell ◽  
Wild Type ◽  
Submerged Cultures ◽  
Slime Mould ◽  
Polysphondylium Pallidum ◽  
Exogenous Agents ◽  
Cellular Slime

Submerged cultures of wild-type Polysphondylium pallidum (WS320) undergo a developmental sequence in which cells agglutinate and form tight aggregates within which extensive stalk and some spore differentiation occurs. Development of submerged cultures of P. pallidum bears many similarities to fruiting body cultures except that differentiation occurs in the absence of morphogenesis. Here we extend the results of an earlier study of submerged cultures of P. pallidum WS320 (Paterno and O'Day. 1981. Can. J. Microbiol. 27: 924–936) by showing that these cultures respond to several exogenous agents (cyclic AMP, lithium chloride, ammonium chloride, colchicine, and concanavalin A) in the same way as slime mould fruiting body cultures. However, two mutants abnormal in cyclic AMP production which complement to form fruiting bodies on agar plates could not form normal submerged culture aggregates when mixed together. Complementation tests with mutant and wild-type cells also failed. The inability of the mutants (PN507 and PN518) to complement in submerged cultures suggests that their fruiting complementarity may be based on a morphogenetic event. A low molecular weight fraction from wild-type cells could enhance development and stalk cell differentiation in WS320 and one mutant, PN507, but not in PN518. Together these data reveal that submerged cultures can be utilized to test the effects of extracellular factors on development and used as a source for the isolation of factors that regulate cellular differentiation.

scholarly journals Induction of β-Lactamase Influences the Course of Development in Myxococcus xanthus

1999 ◽  
Vol 181 (20) ◽  
pp. 6319-6331 ◽  
Author(s):  
Kathleen A. O’Connor ◽  
David R. Zusman
Keyword(s):  
Fruiting Body ◽  
Liquid Culture ◽  
Specific Activity ◽  
Myxococcus Xanthus ◽  
Signal Transduction Pathway ◽  
Transduction Pathway ◽  
Negative Bacterium ◽  
Wild Type ◽  
Multicellular Aggregates ◽  
Transmission Electron

ABSTRACT Myxococcus xanthus is a gram-negative bacterium that develops in response to starvation on a solid surface. The cells assemble into multicellular aggregates in which they differentiate from rod-shaped cells into spherical, environmentally resistant spores. Previously, we have shown that the induction of β-lactamase is associated with starvation-independent sporulation in liquid culture (K. A. O’Connor and D. R. Zusman, Mol. Microbiol. 24:839–850, 1997). In this paper, we show that the chromosomally encoded β-lactamase of M. xanthus is autogenously induced during development. The specific activity of the enzyme begins to increase during aggregation, before spores are detectable. The addition of inducers of β-lactamase in M. xanthus, such as ampicillin, d-cycloserine, and phosphomycin, accelerates the onset of aggregation and sporulation in developing populations of cells. In addition, the exogenous induction of β-lactamase allowsM. xanthus to fruit on media containing concentrations of nutrients that are normally too high to support development. We propose that the induction of β-lactamase is an integral step in the development of M. xanthus and that this induction is likely to play a role in aggregation and in the restructuring of peptidoglycan which occurs during the differentiation of spores. In support of this hypothesis, we show that exogenous induction of β-lactamase can rescue aggregation and sporulation of certain mutants. Fruiting body spores from a rescued mutant are indistinguishable from wild-type fruiting body spores when examined by transmission electron microscopy. These results show that the signal transduction pathway leading to the induction of β-lactamase plays an important role in aggregation and sporulation in M. xanthus.

Effect of Cyclic AMP and Cyclic GMP on Thromboplastin (Factor III) Synthesis in Human Monocytes In Vitro

1983 ◽  
Vol 50 (04) ◽  
pp. 804-809 ◽  
Author(s):  
Torstein Lyberg
Keyword(s):  
Cyclic Amp ◽  
Cyclic Gmp ◽  
Immune Complexes ◽  
Phosphodiesterase Inhibitors ◽  
Inhibitory Effect ◽  
Intracellular Camp ◽  
Human Monocytes ◽  
Purified Protein Derivative ◽  
A 23187

SummaryHuman monocytes in vitro respond to various agents (immune complexes, lectins, endotoxin, the divalent ionophore A 23187, 12-0-tetradecanoyl-phorbol 13-acetate [TPA], purified protein derivative [PPD] of Bacille Calmette-Guerin) with an increased synthesis of the protein component of thromboplastin. The effect of cyclic AMP and cyclic GMP on this response has been studied. Dibutyryl-cyclic AMP, prostaglandin E1 and the phosphodiesterase inhibitors 3-butyl-1-methyl-xanthine (MIX) and rac -4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone (Ro 201724), separately and in combination have a pronounced inhibitory effect on the response to immune complexes and PPD, and a moderate effect on the response to endotoxin and lectins. The effect on TPA response and on the response to A 23187 was slight. Dibutyryl-cyclic GMP (1 mM) gave a slight inhibition of the TPA arid IC response, but had essentially no effect on the response to other inducers. The intracellular cAMP level increased when monocytes were incubated with IC, TPA or A 23187 followed by a decrease to basal levels within 1-2 hr, whereas lectin (PHA) and PPD did not induce such changes. The cAMP response to endotoxin varied. Stimulation with IC induced an increase in monocyte cGMP levels, whereas the other stimulants did not cause such changes.

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