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Biomedical subjects

R Seeger

Publications and source records attributed to R Seeger.

At least 37 records · Page 2Linked to original sources
PubMed1981

Rubescenslysin and phallolysin release marker molecules from phospholipid cholesterol liposomes.

Multilamellar liposomes were prepared from phospholipid, cholesterol and dicetyl phosphate and marked with potassium chromate or with glucose. They were treated with 0.5--50 haemolytic units (HU)/ml of rubescenslysin from Amanita rubescens or of phallolysin from Amanita phalloides. Rubescenslysin caused a dose-dependent release of marker molecules from phosphatidylcholine and from sphingomyelin liposomes. A statistically significant marker leakage was caused by 0.5--1 HU/ml from liposomes prepared from sphingomyelin, phosphatidylcholine from egg yolk, and among the synthetic phosphatidylcholines from distearoyl greater than dipalmitoyl greater than dioleoyl phosphatidylcholine. With the lysin concentrations tested, at the best 50% of total markers were released from sphingomyelin liposomes and 75--95% from phosphatidylcholine liposomes. Also phallolysin released marker molecules from phosphatidylcholine liposomes; statistically significant amounts were released by 0.5 HU/ml from egg yolk phosphatidylcholine and from dipalmitoyl congruent to distearoyl greater than dioleoyl phosphatidylcholine liposomes; 60--90% of maximum release was achieved at the best. However, liposomes prepared from (bovine) sphingomyelin were resistant to phallolysin; even with 50 HU/ml no leakage of markers was observed. Heat-inactivated rubescenslysin, heat-inactivated phallolysin and human serum albumin failed to release markers. Our results lead to the conclusion that both, rubescenslysin and phallolysin, interact with membrane phospholipids, phallolysin showing a higher degree of specificity.

Amanitins↗
PubMed1980

Degranulation of rat mast cells in vitro by the fungal cytolysins phallolysin, rubescenslysin and fascicularelysin.

Phallolysin from Amanita phalloides (Vaill. ex Fr.) Secr., rubescenslysin from Amanita rubescens (Pers. ex Fr.) Gray, and fascicularelysin from Hypholoma fasciculare (Huds. ex Fr.) Kummer, in vitro caused disruption of mast cells in rat mesentery. The mast-cell-degranulating potency of rubenscenslysin and fascicularelysin roughly corresponded to their haemolytic potency; the dose-response curves were extremely steep and the cells were either completely destroyed or remained intact. The action of rubescenslysin and fascicularelysin was very fast: at 37 degrees C 95 resp. 90% of the cells were disrupted within 5 min. Phallolysin degranulated mast cells only at 10-50-fold haemolytic concentrations; the concentration-response curve was flatter, and the effect less radical: a high percentage of the cells underwent only incomplete degranulation. 75% of the cells were degranulated within 5 min. Fascicularelysin released marker molecules from both, lecithin and sphingomyelin liposomes.

Amanitins↗
PubMed1978

[The potassium content of mushrooms (author's transl)].

The potassium content of 410 species (1075 samples) of wild mushrooms ranged between 1.5 and 117g/kg dry wt. It was dependent on species and genus, and on the average was highest in Coprinaceae and lowest in Polyporaceae. A positive correlation was observed between potassium and water content; consequently, the potassium content of the wet wt. showed less variation: it ranged between 0.6 and 14.6 g/kg. In the solid matter of single fruit-bodies (11 species) potassium was distributed as follows: flesh of the cap greater than stem greater than gills or tubes greater than spores. The flesh of the cap contained maximally 1.8 times the potassium of the gills. But due to a correspondingly higher water content, significant potassium differences between fresh weights of these parts of fruit-bodies were uncommon. Potassium was concentrated 20--40-fold in fruit-bodies as compared with the soil.--According to our results mushrooms rank among the most potassium-rich vegetables, appropriate for consideration in diets in chronic potassium deficiency. On the other hand, toxic effects must be considered, especially in cases of renal insufficiency.

Basidiomycota↗
PubMed1978

[Cadmium in mushrooms (author's transl)].

The cadmium content of 402 species of wild mushrooms was determined by flameless atomic absorption spectroscopy. Altogether 1049 samples, grown mainly, in southern Germany, were tested. The cadmium content was between less than 0,1 and 120 mg/kg dry weight, equivalent to less than 0,01 and 10,8 mg/kg fresh weight. Samples with low cadmium content were predominant: 68% of the samples contained less than 2 mg/kg dry weight, 86.5% contained less than 5 mg/kg dry weight, equivalent to about less than 0,2 and less than 0,5 mg/kg fresh weight, respectively. The cadmium content was clearly species-dependent, and to a lesser extent genus-dependent. Samples containing more than 10 mg/kg dry weight occurred in 41 species, among these were 9 Tricholomataceae, 10 Agaricaceae, 11 Cortinariaceae, 3 Amanitas and 4 Russula species. Samples containing more than 50 mg/kg dry weight were found in Agaricus augustus, A perrarus, A. silvicola, A. macrosporus, A. maleolens, and Inocybe bongardii. In single fruiting-bodies the lowest cadmium content was found in the stem, whereas the highest content was found in the gills and tubes. Cadmium content of the gills was at most five times the amount present in the cup. In cadmium-rich mushrooms a marked concentration as compared with the cadmium content of the soil had occured.

Basidiomycota↗
PubMed1978

New neural cell lines derived from experimentally induced rat tumors and from human neuroblastomas.

We have isolated a series of new cell lines from tumors of the nervous system. Two approaches have been used. In the first, tumors were induced in neonatal rats with the potent carcinogen ethylnitrosourea. Tumors were put into cell culture and cloned after several passages. The resultant cell lines were characterized for a variety of presumptive neuronal and glial functions. Our second approach, designed to identify lines with neuronal characteristics, has been to culture and analyze cells derived from human neurolbastomas. Five lines have been characterized for the Na+ action potential ionophore and several enzyme markers.

Acetylcholine↗
PubMed1978

[Changes in erythrocyte shape and volume caused by silymarin].

In vitro treatment of fresh human red cells with silymarin as well as its individual components silybin and silydianin (10(-4) and 10(-3) g/ml of water-soluble sodium or hemisuccinate sodium salt) resulted in disc-crenated sphere transformation of the erythrocyte shape, silydianin being least effective. 10(-4) g/ml of each compound tested, causing only slight changes of the shape of the erythrocytes, significantly increased their maximum diameter, whereas 10(-3) g/ml silymarin or silybin, resulting in a marked sphering of the cells, significantly decreased their maximum diameter. Mean cell volume in isotonic medium determined by Coulter counter method was significantly increased by 10(-3) g/ml silymarin, silybin, silydianin and, above all, chlorpromazin. 2 x 10(-5) g/ml chlorpromazine significantly increased the critical haemolytic volume in hypotonic medium, determined by microhaematocrit method, whereas an insignificant increase of the critical haemolytic volume was induced by 2.7 x 10(-4) g/ml silymarin.

Chlorpromazine↗
PubMed1976

[Elimination of toxic peptides from amanita phalloides by charcoal perfusion in vitro (author's transl)].

Charcoal perfusion in vitro resulted in virtually complete detoxication of an extract from 170 g of Amanita phalloides in aqueous or plasma protein solution. After 4 min of perfusion the amanitin content was reduced to 1-2% after 15 min it was less than 1% of the starting material. Under the same conditions toadstool toxin was eliminated from plasma protein solution too: after 4 min of perfusion a dose of remaining material, corresponding to the LD70 of the starting material, was nontoxic in mice.

Amanitins↗
PubMed1976

[Lead in mushrooms (author's transl)].

The lead content of 222 species of wild mushrooms, either edible or poisonous, was determined by graphite furnace atomic absorption spectroscopy. Altogether 494 samples, grown in rural regions of southern Germany, were tested. The lead content was between less than 2.0 and 40.4, on the average 10.6 mg/kg dry weight, equivalent to less than 0.1 and 3.0, on the average 1.06 mg/kg fresh weight.

Basidiomycota↗
PubMed1976

The haemolytic effect of phallolysin.

Phallolysin from the toadstool, Amanita phalloides, is a basic protein that causes direct haemolysis of red cells. The dose-response curve is steep; the pH optimum is in the weakly acid range. The rate of haemolysis increases with the concentration of the lysin, the optimal temperature is 20 degrees C. The percentage haemolysis-time curves are S-shaped. Haemolysis is of the non-osmotic type. Ca2+ is not required but inhibits haemolysis in a concentration-dependent fashion, as do Mg2+ and Zn2+. The red cell sensitivity of various animal species decreases in the following sequence:mouse greater than rabbit = guniea pig greater than rat greater than man greater than dog approximately or equal to pig greater than sheep = cattle. Red cells of cattle and sheep are largely resistant. Phallolysin is virtually not consumed on haemalysis: the amount of haemoglobin released increases with the number of red cells applied; on repeated addition of fresh red cells the haemolysate retains its full activity. Phallolysin is not inhibited by serum, albumin, cholesterol, lecithin, cephalin or sphingomyelin; inhibition by red cell ghosts of phallolysin haemolysis is considerably less than that of digitonin haemolysis. At sublytic concentrations phallolysin, unlike benzalkonium chloride, liberates practically no membrane lipids from human red cells. Surface activity of phallolysin does not exceed that of bovine serum albumin.-A saponin-like interaction with cholesterol as the basic mechanism of haemolysis can be disregarded. There is also no evidence suggesting a detergent-like effect.

Amanitins↗
PubMed1976

Scanning electron microscopic studies on the cytolytic effect of phallolysin on isolated rat hepatocytes and AS-30 D hepatoma cells.

Rat hepatocytes and AS-30 D hepatoma cells were treated in vitro with phallolysin, the toxic haemolysin from the death cap fungus Amanita phalloides. Scanning electron microscopy revealed dose-dependent formation of bulky protrusions on the cell surface, which later on burst, expelling intracellular material into the surrounding medium, while the cells became stainable with trypan blue. After 1 haemolytic unit (HU)/ml the protrusions burst within 10 min; after 3 HU/ml all cells were destroyed within 3-5 min. Susceptibility of hepatoma cells did not differ from that of hepatocytes.

Amanitins↗
PubMed1976

[Distribution of mercury in the fruit-bodies of Boletus edulis and Agaricus species (authors transl)].

The mercury content of various parts of single fruit-bodies of the Yellow Bolete Boletus edulis (n = 26), the Field-Mushroom Agaricus campester (n = 23) and of Agaricus silvicola (n = 17) was determined by flameless atomic absorption spectroscopy. In each species the lowest mercury content was found in the stem (x = 1,96--3,21 mg/kg dry wt.), whereas the caps contained significantly more mercury (x = 4,19--6,97 mg/kg dry wt.). The highest mercury content was found in the gills and tubes (x = 4,85--8,77 mg/kg dry wt.), which contained significantly more mercury then the flesh of the caps (x = 3,11--5,60 mg/kg dry wt.). Young mushrooms seemed to contain more mercury then older ones.

Agaricales↗
PubMed1976

[Mercury content of mushrooms (author's transl)].

The mercury content of 236 species of wild mushrooms was determined by flameless atomic absorption spectroscopy. Of each species several samples--altogether 616--were tested. The mercury content was between 0.04 and 21.60 mg/kg dry weight, equivalent to 0.002 and 3.090 mg/kg fresh weight. The mercury content was clearly species-dependent. Mercury-rich species particularly were found in Tricholomataceae, Agaricaceae and Lycoperdaceae, whereas in Boletaceae, Amanitaceae and Russulaceae mercury-rich species were rather rare. There was a considerable variability within species, too; hence, other factors, yet unknown, must also determine the mercury content. Geographical influences were not demonstrable. All mushrooms grown on wood had a very low mercury content. Storing over several years did not diminish the mercury content of dried mushrooms. The highest mercury content was found in a poisonous mushroom, but on the average, poisonous mushrooms contained less mercury than edible ones.

Agaricales↗
PubMed1975

Some physico-chemical properties of phallolysin obtained from Amanita phalloides.

The molecular weight of phallolysin, the toxic haemolysin from Amanita phalloides, was established by gel chromatography to be 30000 daltons. The isoelectric point (I.P.) was found in Ampholine pH 7-10 at 8.34. In Ampholine pH 7-9 the gel chromatographically homogeneous phallolysin was separated into phallolysin A (I.P. 8.06) and phallolysin B (I.P. 7.49). Sodium dodecylsulphate-polyacrylamide gel electrophoresis indicated a molecular weight of 33000 daltons for phallolysin A. Phallolysin was thermo- and acid-labile. It was relatively stable in alkaline solutions. 8 M urea as well as 0.1% sodium dodecylsulphate caused irreversible denaturation. On the other hand, phallolysin showed resistance to diverse proteases (pepsin, trypsin, alpha-chymotrypsin, subtilisin, pronase E, bromelin, proteinase K) and also alpha-amylase and pancreatin. Treatment with proteinase K did not change the molecular weight and the isoelectric points of phallolysin. Resistance to proteases was not due to inhibition of proteases by phallolysin.

Agaricales↗
PubMed1975

Demonstration and isolation of phallolysin, a haemolytic toxin from Amanita phalloides.

Phallolysin, a high-molecular weight, thermo- and alcohol-labile toxin with haemolytic activity, was demonstrated in Amanita phalloides. Phallolysin was isolated from cold aqueous toadstool extracts by precipitation with 40% ammonium sulphate, ion-exchange chromatography on DEAE cellulose, gel chromatography on Biogel P-30 and electrofocussing in Ampholine. Electrofocussing in a flat pH gradient resulted in the separation of the gelchromatographically homogeneous phallolysin into phallolysin A (I.P. 8.06) and phallolysin B (I.P. 7.49). Phallolysin A exhibited 70% purity with respect to its behaviour on polyacrylamide gel electrophoresis when stained with Coomassie Brilliant Blue. On the average 0.62 mug, at least 0.20 mug of protein was equivalent to 1 haemolytic unit (HU). The i.p. LD50 for mice was found to be 1060 (930--1210) HU/kg.

Agaricales↗
PubMed1975

Toxic effects of phallolysin from amanita phalloides.

Phallolysin, a protein from Amanita phalloides with cytolytic effects in vitro, was highly toxic when given intravenously to rats, mice, rabbits and guinea pigs: i.v. LD50 in rats was 85 Haemolytic Units (HU)/kg, corresponding to 0.05 mg protein/kg b.w. Death ensued from intravascular haemolysis. In rats large doses (600 HU/kg b.w.) caused cardiac death within a few minutes due to liberation of potassium from lysed cells. The serum contained lethal concentrations of potassium. There was also histological evidence of severe renal damage as a result of the haemolysis. In addition, phallolysin directly damaged the isolated guinea pig heart and the isolated rat liver, probably by its action on membranes. Given by mouth, phallolysin was not poisonous to rats.

Amanitins↗