Stabilizing effects of D<sub>2</sub>O on the microtubular components and needle‐like form of heliozoan axopods: A pressure‐temperature analysis

Marsland, Douglas; Tilney, Lewis G.; Hirshfield, M.

doi:10.1002/jcp.1040770209

Cited by 58 publications

(30 citation statements)

References 17 publications

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“…(14,30), high hydrostatic pressure (14,22), and treatment with colchicine and certain other compounds, the dynamic equilibrium is shifted towards the monomer state, resulting in a breakdown of microtubules. Conversely, elevated temperature (19,30), low hydrostatic pressure (19), and D20 (7,19) result in stabilization of microtubular structure due to a shift towards increased polymerization. Thus, conditions which alter the birefringence patterns and microfibrillar deposition also alter the stability of microtubules.…”

Section: Methodsmentioning

confidence: 99%

Ethylene Effects in Pea Stem Tissue

Steen

Chadwick²

1981

Plant Physiol.

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The marked effects of ethylene on pea stem growth have been investigated. Low temperature and coichicine, both known microtubule depolymerization agents, reverse the effects of ethylene in straight growth tests. Low temperature (6 C) also profoundly reduces the effects of gas in terms of swelling, hook curvature, and horizontal nutation. Deuterium oxide, an agent capable of rigidifying microtubular structure, mimics the effects of ethylene. Electron microscopy shows that microtubule orientation is strikingly altered by ethylene. These findings indicate that some of the ethylene responses may be due to a stabilizing effect on microtubules in plant cells.The multinet hypothesis suggests that isodiametric expansion is prevented in normally elongating cells by radially oriented microfibrils in the cell wall (25). The finding that the orientation of microfibrils usually parallels that of microtubules (9, 21) has led to the suggestion that microtubules may be responsible for determining the orientation of newly deposited cellulose microfibrils (21, 23). Colchicine, which is known to alter microfibrillar deposition (12) and produce a mottled birefringence pattern (10), is also known to depolymerize microtubules (3, 12). On the other hand, D20 produces a banded birefringence pattern similar to that exhibited by C2H4-treated tissue (8) and is known to have a "stabilizing" effect on microtubules (13). were incubated for various times at 24 C in the light or dark. After the predetermined period of time, epicotyls were cut from the seed and shadow-graphed. Hook angles were measured with a protractor (16).Straight Growth Tests. Seeds were soaked as previously described, germinated in plastic bins containing moist vermiculite and grown in darkness at 24 C for 7 days. Under dim green light, 10-mm subhook sections were excised from the third internode of selected seedlings (plants whose third internode was less than 30 mm). Ten sections were floated in 10 ml standard growth media 12% sucrose, (w/v), 5 mm CoCl2, 5 mim phosphate buffer (pH 6.8), 1 mm IAA, and appropriate concentrations of colchicine and C2H4J in 125-ml Erlenmeyer flasks which were sealed with vaccine caps and gently shaken in the dark at 24 C for 12 h. In some experiments, some of the flasks were incubated for 48 h at 6 C. After incubation, C2H4 levels were determined by GC, stem sections were weighed on an analytical balance, and lengths were measured to the nearest 0.1 mm.Long Term Low Temperature Experiments. Pea seeds were surface-sterilized with a 5% Clorox solution, rinsed and soaked in sterile water for 6 h, and planted in moist vermiculite in autoclaved 1-liter glass jars. The jars were sealed with air-tight lids and appropriate concentrations of C2H4 were introduced. They were incubated at 6 C for up to 60 days in the dark. At 3-day intervals, the jars were ventilated and fresh C2H4 was introduced. Observations were made and pictures were taken periodically.

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Section: Methodsmentioning

confidence: 99%

Ethylene Effects in Pea Stem Tissue

Steen

Chadwick²

1981

Plant Physiol.

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“…Exogenous cAMP, or compounds which increase its cellular concentration, also reduces antigeninduced histamine release from sensitized leukocytes (14,15) and lung tissue (16,17). In contrast, deuterium oxide (D20) favors formation of microtubules (18,19) and augments histamine release from leukocytes (20,21). Moreover, it has been reported that a-adrenergic agents (which decrease cAMP levels) and cholinergic agonists, enhance the immunologic release of histamine and slow-reacting substance of anaphylaxis (SRS-A) from human lung fragments (22).…”

Section: Introductionmentioning

confidence: 99%

Mechanisms of Lysosomal Enzyme Release from Human Leukocytes II. EFFECTS OF cAMP AND cGMP, AUTONOMIC AGONISTS, AND AGENTS WHICH AFFECT MICROTUBULE FUNCTION

Zurier¹,

Weissmann²,

Hoffstein³

et al. 1974

J. Clin. Invest.

539

182

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A B S T R A C T Selective release of inflammatory ma-terials from leukocyte lysosomes is reduced by compounds which increase cyclic 3',5'-adenosine monophosphate (cAMP) levels in suspensions of human leukocytes and is augmented by agents which increase cyclic 3',5'-guanosine monophosphate (cGMP) levels in these cell suspensions. Lysosomal enzymes are released in the absence of phagocytosis when cytochalasin B (5 ,ug/ml) converts polymorphonuclear leukocytes (PMN) to secretory cells: lysosomes merge directly with the plasma membrane upon encounter of PMN with zymosan, and cells selectively extrude substantial proportions of lysosomal, but not cytoplasmic enzymes. P-Adrenergic stimulation of human leukocytes produced a dose-related reduction in P-glucuronidase release (blocked by 10' M propranolol) whereas a-adrenergic stimulation (phenylephrine plus propranolol) was ineffective. In contrast, the cholinergic agonist carbamylcholine chloride enhanced enzyme secretion, an effect blocked by 1 0' M atropine. Incubation of cells with exogenous cAMP or with agents that increase endogenous cAMP levels (prostaglandin E1, histamine, isoproterenol, and cholera enterotoxin) reduced extrusion of lysosomal enzymes; in contrast, exogenous cGMP and carbamylcholine chloride (which increases endogenous cGMP levels), increased fi-glucuronidase release. Whereas colchicine (5 X 10-' M), a drug which impairs microtubule integrity, reduced selective enzyme release, deuterium oxide,

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“…Marsland concluded that the hydrostatic pressure is acting on the microtubules directly and, further, that the sites of interaction of the subunits are blocked by shells of bound water which must be dispersed as polymerization takes place (7,12,13). The effect of the hydrostatic pressure reported earlier (i.e., microtubule depolymerization) is consistent with an increase in volume of the reaction of polymerization.…”

Section: Resultsmentioning

confidence: 60%

Stability of Neuronal Microtubules to High Pressure In Vivo and In Vitro

O'Connor

Houston

Samson

1974

Proc. Natl. Acad. Sci. U.S.A.

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Neuronal microtubules in a variety of nerve cell types are unaffected by high hydrostatic pressures over a range of 1400-10,000 pounds/inch2 and periods of 10-45 min. Similarly, purified tubulin polymerized to form microtubules in vitro were not depolymerized by the same range of pressures. The depolymerization of microtubules in several types of non-neuronal cells, which has been reported, may have been over-generalized with regard to the direct action of pressure on microtubule stability.Within the past several years the knowledge of the structure and biochemistry of microtubules has advanced rapidly (1-3). In view of their ubiquity and their functional importance to the cell, a better understanding of the forces of interactions between tubulin subunits that result in polymerization-depolymerization will improve our concept of the physiological mechanisms of the control and action of microtubules.The commonly held view is that microtubules are sensitive to hydrostatic pressure (3)(4)(5)(6). This view is supported by reports that the microtubules of the mitotic apparatus are depolymerized by hydrostatic pressure in the range of 3000-3800 lbs./inch2 (7). Further, it was shown that the microtubules of the heliozoan axopodium are sensitive to high hydrostatic pressure (5). That is, pressures ranging from 4000 to 8000 lbs./inch2 caused a rapid disintegration of the microtubules of the axopodia and cytosome of Actinosphaerium nucleofilum. A wide variety of cells tend to become rounded and lose their motility when exposed to pressure at 4000-8000 lbs./inch2, including amoebae, human fibroblasts in tissue culture, various gate the direct effects of pressure on microtubule assembly. It was found that high hydrostatic pressure did not depolymerize either the microtubules of vertebrate neurons or microtubules in vitro, prepared from purified beef brain tubulin. MATERIALS AND METHODSThe pressure chamber used in this study was similar to the one designed by Landau and Thibodeau (8). This chamber permits tissues to be fixed under high pressure without decompression. Basically, it is two chambers in one, with the inner assembly consisting of two compartments separated by a thin cover glass. Living tissue is placed in one of the compartments. This compartment is separated from the compartment containing the fixative by the cover glass. The ends of the two compartments are covered with rubber diaphragms which allow the pressure to be transmitted equally to the tissue and fixative. The inner assembly, containing the tissue and fixative, is placed in a large outer pressure cylinder and the latter is then filled with water.The pressure cylinder was connected to a hand-operated hydraulic pump (American Instrument Co.). This assembly allowed compressions up to 10,000 lbs./inch2, with the pressures reached in less than 5 sec. After compression, the valve to the pressure cylinder was closed and the cylinder was disconnected from the pump. The cylinder with "sealed in" pressure was, after a period of time, inverted and shake...

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Stabilizing effects of D₂O on the microtubular components and needle‐like form of heliozoan axopods: A pressure‐temperature analysis

Cited by 58 publications

References 17 publications

Ethylene Effects in Pea Stem Tissue

Ethylene Effects in Pea Stem Tissue

Mechanisms of Lysosomal Enzyme Release from Human Leukocytes II. EFFECTS OF cAMP AND cGMP, AUTONOMIC AGONISTS, AND AGENTS WHICH AFFECT MICROTUBULE FUNCTION

Stability of Neuronal Microtubules to High Pressure In Vivo and In Vitro

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Stabilizing effects of D2O on the microtubular components and needle‐like form of heliozoan axopods: A pressure‐temperature analysis

Cited by 58 publications

References 17 publications

Ethylene Effects in Pea Stem Tissue

Ethylene Effects in Pea Stem Tissue

Mechanisms of Lysosomal Enzyme Release from Human Leukocytes II. EFFECTS OF cAMP AND cGMP, AUTONOMIC AGONISTS, AND AGENTS WHICH AFFECT MICROTUBULE FUNCTION

Stability of Neuronal Microtubules to High Pressure In Vivo and In Vitro

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Stabilizing effects of D₂O on the microtubular components and needle‐like form of heliozoan axopods: A pressure‐temperature analysis