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Influence of air pollutants and nutrient deficiency on D-1 protein content and photosynthesis in young spruce trees (1992)

Lütz, C. ; Steiger, A. ; Godde, D.

Oxford, UK : Blackwell Publishing Ltd

Physiologia plantarum 85 (1992), S. 0

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ISSN: 1399-3054

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: Long-term fumigation with different mixtures of air pollutants, such as O3, NO2 and SO2, in combination with potassium deficiency in 4-year-old spruce trees shows clearly that the photosynthetic apparatus reacts very sensitively to environmental stress. Even when no change in photosynthetic oxygen evolution of the leaves was measurable, the content of D-1 protein in the reaction center of photosystem II already increased significantly at low stress conditions. With increasing concentrations of pollutants, the content of D-1 protein decreased considerably. This pattern was observed with all combinations of gases, although they differed in effectiveness. The most potent effect on the content of D-1 protein was found with a combined fumigation of SO2 plus NO2. Obviously, the ratio between synthesis and degradation of the D-1 protein is influenced by stress factors. However, the content of D-1 protein was not strongly correlated with photosynthetic oxygen evolution in whole needles nor with electron transport rate in isolated thylakoids. Under controlled potassium deficiency, effects similar to those observed upon ozone fumigation developed. The results suggest unspecific stress answers for the D-1 content and the photosynthetic reactions rather than specific responses.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1399-3054.1992.tb04762.x

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Flumazenil exerts intrinsic activity on sleep EEG and nocturnal hormone secretion in normal controls (1994)

Steiger, A. ; Guldner, J. ; Lauer, C. J. ; [et al.]

Springer

Psychopharmacology 113 (1994), S. 334-338

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ISSN: 1432-2072

Keywords: Sleep EEG ; Cortisol ; Growth hormone ; Flumazenil ; Midazolam

Source: Springer Online Journal Archives 1860-2000

Topics: Medicine

Notes: Abstract The physiological function of benzodiazepine (BDZ) receptors includes regulation of sleep and neuroendocrine activity. Most of the pharmacological effects of BDZ are blocked by flumazenil. However, recent neurological and behavioral studies suggest that flumazenil has its own central intrinsic activity. This issue was addressed in a study of the sleep EEG and the nocturnal secretion of growth hormone and cortisol in ten normal male controls, who were given flumazenil either alone or in combination with the BDZ agonist midazolam, placebo and midazolam alone. Flumazenil prompted an increase in sleep onset latency, a decrease in slow wave sleep and an increase in wakefulness. Plasma cortisol concentrations after flumazenil administration were lower than after midazolam. Both flumazenil and midazolam decreased nocturnal growth hormone secretion. After simultaneous application of both BDZ receptor ligands the growth hormone blunting was amplified. Our study demonstrates that at the level of the sleep EEG and neuroendocrine activity flumazenil is capable of exerting both agonistic and inverse agonistic or antagonistic effects.