Vitalfärbungsversuche mit reduziertem Neutralrot an „vollen“ Zellsäften einiger höherer Pflanzen

Ohne ZusammenfassungDie vorliegenden Versuehe wurden während meines kurzen Aufenthalts im Pflanzenphysiologisehen Institut der Universität Wien ausgeführt. Herrn Prof. Dr. Karl Höfler und Herrn Dr. H. Kinzel danke ich sehönstens auch an dieser Stelle für die Untersfützung während der Arbeit.     

Intravenous thrombolysis for acute ischemic stroke--our experiences

Intravenous (i.v.) thrombolysis with recombinant tissue plasminogen activator (rt-PA) is the only available pharmacological therapy to improve the outcome of acute ischemic stroke. We compared 71 patients presenting with ischaemic stroke and given intravenous rt-PA (0.9 mg/kg total dose) within 3 h with 71 patients who present to the hospital more than 3 hours after stroke symptom onset. The primary endpoint was the modified Rankin scale (mRS) at 90 days, dichotomised for favourable and unfavourable (score 2-6). Outcome measures were symptomatic intracerebral haemorrhage within 36 h (haemorrhage associated with National Institutes of Health Stroke Scale [NIHSS] > or = 4 points deterioration), and mortality at 3 months. More patients had favourable outcome with the rt-PA-treated group than with the control group (64.79% vs. 22.54%; p = 0.0001). The greater proportion of patients left with minimal or no deficit 90 days after rt-PA treatment, as compared with the control group. In the treated group symptomatic intracranial hemorrhage occurred in 1 patient who recovered to a level of functional independence, and asymptomatic intracranial hemorrhage was observed in 2 patients. Our experience of an acute stroke thrombolysis service shows that we are able to provide this treatment safely and in accordance with established treatment guidelines. We recommend thrombolytic treatment in acute ischemic stroke for selected population.     

Grafting influence on the weight and quality of tomato fruit under salt stress

Two commercial tomato cultivars were used to determine whether grafting could prevent decrease of fruit weight and quality under salt stress conditions. The cultivars Buran F1 and Berberana F1 were grafted onto rootstock ‘Maxifort’ and grown under three levels of elevated soil salinity (EC 3.80 dS m^?1, 6.95 dS m^?1 and 9.12 dS m^?1). Fruit weight reduction of grafted plants was lower (about 20–30%) in comparison with non‐grafted ones. Salt stress at the second salinity level (EC 6.95 dS m^?1) induced the highest alteration of examined growth and quality parameters. The total increase of phenols, flavonoids, ascorbate and lycopene content in the fruits of both grafted and non‐grafted plants for both cultivars had a similar trend and intensity, though some inter‐cultivar variation was observed. The possibility of grafting tomato plants to improve salt tolerance without fruit quality loss is discussed.     

Characterisation of antioxidants in photosynthetic and non‐photosynthetic leaf tissues of variegated Pelargonium zonale plants

Hydrogen peroxide is an important signalling molecule, involved in regulation of numerous metabolic processes in plants. The most important sources of H₂O₂ in photosynthetically active cells are chloroplasts and peroxisomes. Here we employed variegated Pelargonium zonale to characterise and compare enzymatic and non‐enzymatic components of the antioxidative system in autotrophic and heterotrophic leaf tissues at (sub)cellular level under optimal growth conditions. The results revealed that both leaf tissues had specific strategies to regulate H₂O₂ levels. In photosynthetic cells, the redox regulatory system was based on ascorbate, and on the activities of thylakoid‐bound ascorbate peroxidase (tAPX) and catalase. In this leaf tissue, ascorbate was predominantly localised in the nucleus, peroxisomes, plastids and mitochondria. On the other hand, non‐photosynthetic cells contained higher glutathione content, mostly located in mitochondria. The enzymatic antioxidative system in non‐photosynthetic cells relied on the ascorbate–glutathione cycle and both Mn and Cu/Zn superoxide dismutase. Interestingly, higher content of ascorbate and glutathione, and higher activities of APX in the cytosol of non‐photosynthetic leaf cells compared to the photosynthetic ones, suggest the importance of this compartment in H₂O₂ regulation. Together, these results imply different regulation of processes linked with H₂O₂ signalling at subcellular level. Thus, we propose green‐white variegated leaves as an excellent system for examination of redox signal transduction and redox communication between two cell types, autotrophic and heterotrophic, within the same organ.     

The influence of coumestrol,zearalenone, and genistein administration on insulin receptors and insulin secretion in ovariectomized rats

The influence of phytoestrogens (genistein and coumestrol) and mycoestrogen (zearalenone) on insulin secretion, liver insulin receptors and some aspects of lipid and carbohydrate metabolism were investigated in this study. Ovariectomized rats were injected s.c. with the above mentioned compounds in the amount of 1 mg for three days. Coumestrol and zearalenone caused a significant increase in uterus weight, similar to the effects observed after estrone action, while this effect was not observed after the genistein injection. Blood insulin level was not changed after phyto- or mycoestrogen treatment. However, coumestrol and genistein significantly decreased the binding capacity of liver insulin receptors. These changes corresponded with alterations in glucose and free fatty acids profiles in blood, as well as with glycogen content in liver. The effects observed after genistein and coumestrol injections differed from those noticed in rats treated with zearalenone or estrone. On the basis of these results we conclude that metabolic effects of high doses of coumestrol and genistein in ovariectomized rats are partly mediated by changes in insulin sensitivity of the liver and that the action of plant estrogens on metabolism is, at least to the some degree, independent of their estrogen activity.     

Impact of abscisic acid in overcoming the problem of albinism in horse chestnut androgenic embryos

Horse chestnut (Aesculus hyppocastanum L., Hyppocastanacea) is a relict species with a slow and complex reproductive cycle considered to have horticultural and medical importance. The cycle maybe circumvented via in vitro androgenesis. Androgenesis of horse chestnut was induced in microspores and anther culture on MS media. Some of the horse chestnut androgenic embryos were albinos. Addition of abscisic acid in media (in concentrations of 0.01, 0.1, 0.5, 1, 2, 5, 10, and 20 mg l^?1) with horse chestnut androgenic embryos has circumvented the reproduction cycle barriers. The best results were achieved on medium with the lowest abscisic acid concentration (0.01 mg l^?1) in microspore culture. The microspore culture proved to be a better model system for embryo production and albino embryo reduction than anther culture. Flow cytometry analysis after maturation treatments induced by ABA showed that 88 % of green embryos originating from microspore culture were haploid. However, 50 % of green embryos from anther culture were haploid. The remaining analyzed androgenic embryos, from both types of cultures were diploid.     

Kinetic model for the bioconversion of glucose to 2,5-diketo-D-gluconic acid

Summary A simple unstructured mathematical model for the oxidation of glucose to 2,5-diketo-D-gluconic acid with Erwinia citreus was developed. The kinetic parameters of the model were estimated by the oxygen partial pressure method and directly from the temporal response obtained from the experimental data collected in the batch fermentation. The simple developed model based on the kinetic measurements was able to simulate quite well the dynamic behaviour of the batch fermentation.