Showing papers by "László Vígh published in 1986"
TL;DR: Levels of polyamines prior to chilling treatment did not appear to be correlated with chill-tolerance as levels in the non-chilled controls were highest in cultivars of medium chill-sensitivity, whereas more chill-sensitive genotypes remained unchanged or slightly declined in putrescine content on chilling.
Abstract: Guye, M. G., Vigh, L. and Wilson, J. M. 1986. Polyamine titre in relation to chill-sensitivity in Phaseolus sp.—J. exp. Bot. 37: 1036-1043. Endogenous levels of the polyamines putrescine, spermidine and spermine were quantified in the primary leaves of five cultivars of bean (Phaseolus sp.) differing in their 'wilting response' to a chilling exposure of 5 °C for 24 h. Levels of polyamines prior to chilling treatment did not appear to be correlated with chill-tolerance as levels in the non-chilled controls were highest in cultivars of medium chill-sensitivity. Plants grown under a vapour saturation deficit (PSD) of 8-4 g m ~ 3 day/6-1 g m ~ 3 night exhibited a mild hardening as compared to plants grown under a VSD of 5-7 g m"3 day/4-1 g m ~3 night, as the former showed less wilting on chilling. Hardening at high VSD had the effect of slightly lowering the putrescine content of non-chilled tissue but total polyamine content remained unchanged. However, on chilling, the largest relative increase in polyamine levels, in particular that of putrescine, occurred in hardened plants. There was also a significant relative increase in putrescine titre in response to chilling in non-hardened genotypes of high chill-tolerance, whereas more chill-sensitive genotypes remained unchanged or slightly declined in putrescine content on chilling. Relative changes in putrescine content rather than absolute levels appears to be correlated with chill-tolerance. These results are discussed in view of present knowledge on the adaptive significance of stress-induced changes in polyamines, especially with regard to membrane stability.
70 citations
TL;DR: It is suggested that cytoplasmic membrane plays a determinative role in the thermal acclimation of the algal cells in nitrate-starved Anacystis nidulans cells.
Abstract: The lipid phase transition of the cytoplasmic membrane and the chilling susceptibility were studied in nitrate-starved Anacystis nidulans cells. Nitrate starvation resulted in the disappearance of the thylakoid membrane system, without any effect on chilling susceptibility. The chilling susceptibility of the algal cells depended on the growth temperature. Temperatures of lipid phase transitions of the cytoplasmic membranes were detected by chilling-induced spectral changes in the carotenoid region, in vivo. These values were identical to those of cultures containing intact thylakoid systems. Our results suggest that cytoplasmic membrane plays a determinative role in the thermal acclimation of the alga cells.
35 citations
TL;DR: The lipid composition of the photosynthetic membrane has been altered by the homogeneous catalytic hydrogenation of the unsaturated fatty acid residues of membrane lipids, which may suggest that the unsaturation level of fatty acids plays a crucial role by ensuring the lateral mobility of plastoquinone between Photosystem II and Photosystem I.
33 citations
TL;DR: The possible role of dehydration-induced structural changes in the bilayer matrix in triggering adaptive alterations in membrane composition, similar to those observed during cold hardening, is discussed.
Abstract: Seedlings of winter wheat (Triticum aestivum L. cv. Jubilejnaja 50) were grown under normal and dry conditions. Frost resistance (LT50) of 10-day-old control seedlings was −6°C. LT50 of the subsequently drought-stressed leaves shifted to −16°C. In plants of the same physiological age (28 days) but grown without stress, LT50 was −12°C. Phosphatidylcholine accumulated and phosphatidylethanolamine decreased in drought-stressed leaves. Fatty acid unsaturation of these phospholipids increased with leaf age, independently of water supply. Both ageing and drought stress produced a decrease in the apparent phase separation temperature of isolated total phospholipids as determined by electron spin resonance. The possible role of dehydration-induced structural changes in the bilayer matrix in triggering adaptive alterations in membrane composition, similar to those observed during cold hardening, is discussed.
32 citations
TL;DR: In the renal tissue, the result of ascorbic acid pretreatment exhibits a similar tendency to that of paraquat treatment, but a more significant one, while the administration of as Corbenic acid together with paraquats does not cause a substantial change in the fluidity index compared to the control.
Abstract: 1. 1. The effects of the simultaneous administration of ascorbic acid and the LD 50 of paraquat (an ingredient of Gramoxone ® ), and of ascorbic acid pretreatment followed by the LD 50 of paraquat, were studied on the phospholipid and trigliceride fatty acid levels in homogenates of mouse lung, liver and kidney. 2. 2. Ascorbic acid treatment increases the content of polyunsaturated fatty acids in the lung considerably, i.e. the pulmonary membrane fluidity decreases significantly in response to ascorbic acid. 3. 3. In the liver homogenate, the membrane fluidity is significantly increased by ascorbic acid pretreatment, and significantly decreased by simultaneous ascorbic acid treatment. 4. 4. In the renal tissue, the result of ascorbic acid pretreatment exhibits a similar tendency to that of paraquat treatment, but a more significant one, while the administration of ascorbic acid together with paraquat does not cause a substantial change in the fluidity index compared to the control.
2 citations