Rapid effects of insulin on cyclic GMP location in an intact protozoan

Kőhidai, László; Bársony, Julia; Roth, Jesse; Marx, Stephen J.

doi:10.1007/bf01928167

Cited by 46 publications

(21 citation statements)

References 23 publications

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“…16,17 It utilizes many signalling pathways analogous to those of mammalian cells, e.g. adenylate cyclase-cAMP, 17 guanylate cyclase-cGMP, 18,19 Ca-calmodulin 20 and the phosphatidylinositol system 21 and provides evidence for the activity of enzymes such as phospholipases A 2 , C and D (PLA 2 , PLC and PLD), which play important roles in the generation of second messengers. [22][23][24] Actin assembly and disassembly are affected by second messengers, e.g.…”

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confidence: 99%

Effect of drugs affecting microtubular assembly on microtubules, phospholipid synthesis and physiological indices (signalling, growth, motility and phagocytosis) inTetrahymena pyriformis

Kovács

Csaba

2006

Cell Biochem. Funct.

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Structural changes of microtubules, incorporation of radioactively labelled components into phospholipids, cell motility, growth and phagocytosis were studied under the effect of four drugs affecting microtubular assembly: colchicine, nocodazole, vinblastine and taxol. Although the first three agents influence microtubules in the direction of depolymerization and the fourth stabilizes them, their effects on the structure of microtubules cannot be explained by this. Using confocal microscopy after an acetylated anti-tubulin label, in nocodazole- and colchicine-treated cells, the basal body cages disappear and longitudinal microtubules (LM) became thinner without changing transversal microtubules (TM). After taxol treatment LM also became thinner, however TM disappeared. Under the effect of vinblastine TM became thinner, without influencing LM. These drugs influence the incorporation of components ([(3)H]-serine, [(3)H]-palmitic acid and (32)P) into phospholipids, however their effect is equivocal and cannot be consequently coupled with the effect on the microtubules. Nocodazole, vinblastine and taxol significantly reduced the cell's motility, however colchicine did so to a lesser degree. Vinblastine and nocodazole totally inhibited, and taxol significantly decreased cell growth, while colchicine in a lower concentration increased the multiplication of cells. Phagocytosis was not significantly influenced after 1 min, but after 5 min all the agents studied (except colchicine) significantly inhibited phagocytosis. After 15 and 30 min each molecule caused highly significant inhibition. The experiments demonstrate that drugs affecting microtubular assembly dynamics influence differently the diverse (longitudinal, transversal etc.) microtubular systems of Tetrahymena and also differently influence microtubule-dependent physiological processes. The latter are more dependent on microtubular dynamics than are changes in phospholipid signalling.

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confidence: 99%

Effect of drugs affecting microtubular assembly on microtubules, phospholipid synthesis and physiological indices (signalling, growth, motility and phagocytosis) inTetrahymena pyriformis

Kovács

Csaba

2006

Cell Biochem. Funct.

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“…Melatonin is also synthesized by the cells, which is infl uenced by the lighting conditions and previous encounter (hormonal imprinting) [16][17][18][19]. Hungarica 62, 2015 Enzymes and genes related to biogenic amines Adenylate cyclase and guanylate cyclase were found in Tetrahymena and their activity was infl uenced by biogenic amines [20][21][22]. Epinephrine stimulated the enzyme's action [23] while in other experiments adrenergic receptor agonists inhibited the enzyme and epinephrine blockers decreased this effect [24].…”

Section: Synthesis and Uptake Of The Biogenic Aminesmentioning

confidence: 99%

Biogenic amines at a low level of evolution: Production, functions and regulation in the unicellular Tetrahymena

Csaba

2015

Acta Microbiologica et Immunologica Hungarica

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The unicellular eukaryote Tetrahymena synthesize, store and secrete biogenic amines (histamine, serotonin, epinephrine, dopamine, melatonin) and also can take up amines from the milieu. It also has (G-protein-coupled) receptors (binding sites) for these amines as well, as second messengers. The factors infuencing the mentioned processes are shown. For certain amines the genes and the coded enzymes are demonstrated. The amines infl uence phagocytosis, cell division, ciliary regeneration, glucose metabolism and chemotaxis. There are interhormone actions between the amines, and between the amines and other hormones produced by Tetrahymena. The critical review discusses the role of amines in the early stages of evolution and compares this to their functions in mammals. It tries to give answer how and why biogenic amines were selected to hormones, and why new functions formed for them in higher ranked animals, preserving also the ancient ones.

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“…Insulin in Tetrahyniena binds to both the plasma membrane and the nuclear membrane (Hegyesi & Csaba, 1992). (3) The effect of insulin in modifying cGMP location in this species (Kohidai et aL, 1992) is specially interesting since the process of exocytosis in higher organisms is regulated by certain Rab proteins (a subset of small GTP-binding proteins) (Zerial & Stenmark, 1993), which also regulate membrane traffic.…”

Section: Comparison With Other Systemsmentioning

confidence: 99%

Differentiation, growth and morphogenesis:Acetabulariaas a model system

1997

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SUMMARY The aim of this paper is to review the present knowledge of the main aspects of differentiation of Acetabularia, a unicellular, eukaryotic organism, and to underline the multiple control pathways modulated by circadian rhythmicity. Growth and morphogenesis are sequentially programmed. Timing of cap differentiation is highly dependent on external conditions. The importance of the sequence of processes is shown by experimental disregulation. The alga is a highly polarized cell, both in morphology and in the relative concentrations of a number of the molecules it contains. Apical cap differentiation is regulated at the post‐transcriptional level and could also depend in part on polyamines and on proteolytic activity. Acetabularia displays a number of circadian rhythms (CR). These rhythms form an elaborate biological time structure (also called temporal morphology, or morphology in time as opposed to morphology in space): the distribution in the 24 h cycle of the peaks and troughs of the oscillating functions. The oscillations display fixed relations both with the other functions and with external conditions (such as the transition from dark to light). Interestingly, the CR modulate Acetabularia's development, which is influenced by photoperiod; we present preliminary experiments suggesting that disruption of temporal morphology is deleterious to morphogenesis. Induction of growth and of morphogenesis are totally dependent on blue light. However, blue light receptors in plants arc probably multiple, but we present arguments suggesting that flavin‐cytochrome b and the associated KHAM‐sensitive molecule are present in Acetabularia plasma membrane and are involved in blue light perception. Agents interfering with different steps of signal perception and transduction show that at least some of these steps are temporally regulated. According to recent experiments from our laboratory, the existence of a redox signalling mechanism appears to be highly probable. The phytohormones (or plant regulators), auxin (indole acetic acid), abscisic acid and ethylene, exert cell‐regulatory functions and are involved in Acetabularia differentiation. They also modulate at least some circadian rhythms. Finally, circadian rhythms intervene in differentiation and are proposed to have an integrative function.

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Rapid effects of insulin on cyclic GMP location in an intact protozoan

Cited by 46 publications

References 23 publications

Effect of drugs affecting microtubular assembly on microtubules, phospholipid synthesis and physiological indices (signalling, growth, motility and phagocytosis) inTetrahymena pyriformis

Effect of drugs affecting microtubular assembly on microtubules, phospholipid synthesis and physiological indices (signalling, growth, motility and phagocytosis) inTetrahymena pyriformis

Biogenic amines at a low level of evolution: Production, functions and regulation in the unicellular Tetrahymena

Differentiation, growth and morphogenesis:Acetabulariaas a model system

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