The Effect of Cycloheximide on Uptake and Transport of lons by Sunflower Roots

Kelday, L. S.; Bowling, D. J. F.

doi:10.1093/oxfordjournals.aob.a085021

Cited by 11 publications

(5 citation statements)

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“…Après désinfection par l'eau oxygénée, les graines de colza (Brassica napus L. variété drakkar 00) sont mises à germer. Six jours après, les plantules sont repiquées sur des seaux en plastique de 6 l, remplis d'une solution nutritive de base [17], aérée de manière constante par des pompes à aquarium. Les cultures sont conduites sous serre, en conditions contrôlées de température (25/18 • C ; jour/nuit) et d'humidité relative (50%).…”

Section: Conditions De Cultureunclassified

Effets du cadmium sur le métabolisme des lipides de plantules de colza (Brassica napus L.)

Youssef¹,

Nouairi²,

Temime³

et al. 2005

Comptes Rendus. Biologies

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Cadmium effects on lipid metabolism of rape (Brassica napus L.). Treatment of rape seedlings with increasing CdCl 2 concentrations in the culture medium resulted in a cadmium accumulation within plant tissues, which increased with external metal dose; such accumulation was more important in roots than in leaves. Biomass production was severely inhibited, even at low cadmium concentration. In leaves, quantities of chloroplastic lipids, monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), sulfolipids (SL) and phosphatidylglycerol (PG) decreased sharply under metallic treatment. However, contents of extrachloroplastic lipids, mainly phosphatidylcholine (PC) and phosphatidylethanolamine (PE) increased significantly. In contrast to leaves, contents of root phospholipids decreased. Likewise, levels of tri-unsaturated fatty acids: linolenic (C18:3) and hexadecatrienoïc (C16:3) dropped in leaves of treated seedlings as compared to those of controls, suggesting that heavy metals induced an alteration in the fatty acid desaturation process or a stimulation of their peroxidation. Also, trans palmitoleic acid (C16:1-trans) level in PG decreased considerably. In roots, there was a slight decrease in C18:3 level, with a concomitant increase in the C18:2 percentage. Radioactive labelling of leaf lipids with (1-14 C) acetate allowed to show that fatty acid biosynthesis was noticeably altered at the highest cadmium dose used (50 µM). Biosynthesis of tri-unsaturated fatty acids was also inhibited which may explain the decline in non-labelled lipid contents. Results showed that metallic ion seems to affect selectively chloroplastic membranes due to an inhibition of polyunsaturated fatty acid biosynthesis. Moreover, a lipid peroxidation occurred in our case because of the spectacular increase of malondialdehyde (MDA) content observed in cadmium treated leaves. To cite this article: N.

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Section: Conditions De Cultureunclassified

Effets du cadmium sur le métabolisme des lipides de plantules de colza (Brassica napus L.)

Youssef¹,

Nouairi²,

Temime³

et al. 2005

Comptes Rendus. Biologies

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“…In tissues where ion-absorption rates are increasing due to washing or aging (13,17,25,26), the inhibition might be reasonably attributed to blocked synthesis of those enzymes required to augment transport rates. In other cases, however, there have been suggestions that protein synthesis inhibitors may have secondary or side effects, possibly interfering with metabolic energy supply (9,14,22 tions, also blocked IAA-induced growth and its associated increases in respiration, H+ efflux, and cell potential. These inhibitions were much less marked when FC was used to induce growth.…”

mentioning

confidence: 99%

Action of Protein Synthesis Inhibitors in Blocking Electrogenic H⁺ Efflux from Corn Roots

Chastain¹,

LaFayette²,

Hanson³

1981

Plant Physiol.

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The block in the electrogenic H+ efflux produced by protein synthesis inhibitors in corn root tissue can be released or by-passed by addition of fusicoccin or nigericin. The It has been repeatedly demonstrated in a wide variety of plant tissues that inhibitors of protein synthesis, such as cycloheximide, will also inhibit energy-linked ion absorption, but the nature of this inhibition is not resolved. In tissues where ion-absorption rates are increasing due to washing or aging (13,17,25,26), the inhibition might be reasonably attributed to blocked synthesis of those enzymes required to augment transport rates. In other cases, however, there have been suggestions that protein synthesis inhibitors may have secondary or side effects, possibly interfering with metabolic energy supply (9,14,22 tions, also blocked IAA-induced growth and its associated increases in respiration, H+ efflux, and cell potential. These inhibitions were much less marked when FC was used to induce growth. They concluded that a short-lived protein(s), possibly functioning with the cell membrane, is involved in IAA-induced cell enlargement but that a residual growth promotion is possible with FC which does not involve new protein synthesis. Bates and Cleland (2), using peeled Avena coleoptiles, found CH and MDMP to inhibit IAA-induced H+ efflux after a 5-to 8-min lag period, which was followed closely by a decline in growth rate. Incorporation of [3HJleucine into protein was strongly inhibited, but respiration was not affected. Cleland and Lomax (7) had previously found FC-induced K+ uptake to be unaffected by CH. FCinduced H+ efflux, unlike that due to IAA, was unaffected by protein synthesis inhibition (2, 6).We have investigated the effects of protein synthesis inhibitors on the H+ efflux, K+ influx, and electrogenic cell potential of washed corn root tissue to determine if the inhibitions discussed above can be related to the regulation of the H+ extrusion as suggested by Marre (21). The most effective protein synthesis inhibitor (MDMP) will completely block H+ efflux after an 8-to 10-min lag, depolarizing the electrogenic potential and strongly inhibiting K+ influx. FC and nigericin will largely release the blocked H+ efflux, restoring the cell potential, but only FC is active in recovering part of the K+ influx. The results are discussed in terms of the putative plasmalemma (H+,K+)-ATPase which in corn roots appears to be responsible for K+ transport and electrogenicity at low K+ concentrations (4, 5, 11). MATERIALS AND METHODSMethods for raising corn seedlings (Zea mays L.,[A6l9xOh43]xA632, Crow's Hybrid Corn Co., Milford, IL), washing 0.5-to 2.5-cm root segments, and following ion and H+ fluxes have been described (12,16). Seeds were sterilized in 1% NaOCl and the seedlings were grown on paper towels wetted with 0. Inmm CaSO4. Root segments were washed for 4 h in aerated 0.2 mm KH2PO4 + 0.2 mm CaSO4 (pH 6.0) at 30 C. This was also the standard solution used in all experiments unless otherwise stated. Net H+ efflux was continu...

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“…However, MacDonaid and Ellis (1969) found that CHM inhibited chloride uptake and uncoupled respiration in a number of tissues. Kelday and Bowling (1975) also found that CHM uncoupled respiration in sunflower roots and inhibited both ion uptake and transport simultaneously.…”

Section: Leakage or Secretion Into The Vessels?mentioning

confidence: 84%

“…However, the data provided by it have proved to be very consistent from a range of species and show an absence of electrical gradient across the root which is in accord with the symplasm concept. Some recent results also reflect the presence of an electrogenic component to the PD (Kelday and Bowling 1980). The presence of the latter indicates that the cells were not damaged by the insertion of the microelectrode, a possibility raised hy Anderson and Higinbotham (1975).…”

Section: Leakage or Secretion Into The Vessels?mentioning

confidence: 85%

Release of ions to the xylem in roots

Bowling

1981

Physiologia Plantarum

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The Effect of Cycloheximide on Uptake and Transport of lons by Sunflower Roots

Cited by 11 publications

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Effets du cadmium sur le métabolisme des lipides de plantules de colza (Brassica napus L.)

Effets du cadmium sur le métabolisme des lipides de plantules de colza (Brassica napus L.)

Action of Protein Synthesis Inhibitors in Blocking Electrogenic H⁺ Efflux from Corn Roots

Release of ions to the xylem in roots

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The Effect of Cycloheximide on Uptake and Transport of lons by Sunflower Roots

Cited by 11 publications

References 0 publications

Effets du cadmium sur le métabolisme des lipides de plantules de colza (Brassica napus L.)

Effets du cadmium sur le métabolisme des lipides de plantules de colza (Brassica napus L.)

Action of Protein Synthesis Inhibitors in Blocking Electrogenic H+ Efflux from Corn Roots

Release of ions to the xylem in roots

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Product

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Action of Protein Synthesis Inhibitors in Blocking Electrogenic H⁺ Efflux from Corn Roots