János Vetter

János Vetter
University of Veterinary Medicine Budapest · Department of Botany

PhD, DSc

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79
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Publications

Publications (79)
Article
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Antioxidant parameters of extracts from whole fruiting bodies and different morphological tissues (peel, inner cap, gills and stipes) of eight popular edible mushrooms were determined and compared. The examined species of both cultivated and wild mushrooms were analysed for total phenolic content (TPC) and free radical scavenging activity (RSA) by...
Article
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Cultivated mushrooms are not only valuable foods of our age (functional foods) but contain certain benefi cial chemical components (high level of K and P, very low content of Na, considerable quantities of some microelements, high and valuable protein but low fat contents). Some cultivated mushrooms have anti-carcinogenic effects caused fi rst of a...
Article
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Effect-directed isolation of free radical scavengers from the methanol extract of the freeze-dried fruiting bodies of the cultivated basidiomycetous mushroom, black poplar (Cyclocybe cylindracea), yielded a β-carboline alkaloid. Its structure was determined based on ESI-TOF-MS/MS, NMR and circular dichroism spectra by comparison with published data...
Chapter
This chapter presents new chemical data on the structure, characteristics, content, and probable biological functions of the secondary metabolites of ferns. The number of isolated new phenolics and terpenoids is high, but the occurrence of alkaloids is very limited; some qualitative data are uncertain. However, it is known that saccharides and alka...
Chapter
The cyanogenic glycosides (CGs) are glycosidic derivatives of α-hydroxynitriles. These molecules are distributed in three phyla of higher plants; the majority of such compounds were isolated and described in dicot plants, and highest occurrence characterizes the subclass Rosidae. Biosynthetic capacity of CGs seems to be an ancient property in plant...
Article
Agaricus bisporus (button mushroom) is one of the most consumed edible mushrooms in the world. The components of its methanol and ethyl acetate extracts were tested for their ability to inhibit the growth of a soil bacterium Bacillus subtilis utilizing direct bioautography (thin-layer chromatography (TLC) coupled with bioassay). The active componen...
Article
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King oyster mushroom (Pleurotus eryngii) is a worldwide cultivated mushroom of appreciated nutritional and medicinal quality. Aims of these investigations were to give new comparative data for the better evaluation of P. Eryngii. Results of our investigations can be summarized as follows: P. Eryngii has higher (crude protein, crude fat) or at least...
Article
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Laetiporus sulphureus (chicken of the woods) is a wood decaying mushroom with positive medicinal and biological effects. The aim of this study was to determine its chemical composition including the main organic components (protein, fat, fibre, and ash contents, different protein fractions, the free amino acid level, soluble oligo- and polysacchari...
Article
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Background Data of mushroom nitrate content from scientific studies is limited. There have been two such recent investigations (mainly regarding certain cultivated species). To obtain comparable analytical data, we analyzed 134 samples of 54 taxa gathered and prepared by our Department.ResultsThe mushroom species were evaluated according to their n...
Article
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Death cap (Amanita phalloïdes) and fool's mushroom (Amanita verna) are the most important amatoxin containing mushrooms in Central-Europe. These toxins belong to the cyclic octapeptides; their chemical structure (as triptathionin) is unusual, they have a great stability (against heat, acids and digestive enzymes). Humans and mammals are very suscep...
Article
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Summer truffle (Tuber aestivum Vittadini) is one of the most important mycorrhizal mushrooms with underground fruit bodies. Formerly the scientific investigations were focused mainly on its specific fragrant constituents. Our work was concentrated on complex chemical characterization including different organic and inorganic components. Summer truf...
Article
In the course of the work, 93 samples from 17 hypogeous fungus species belonging to 6 genera were taken from various habitats in Hungary and were analysed for the concentrations of 22 elements using the inductively coupled plasma spectroscopy ICP method. All the measurements were made in three independent replications. The data were compared with t...
Article
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The edible mushrooms have different valuable chemical properties (proteins, minerals, aromatic compounds, low lipid and energy contents, etc.) but there are practically no data about the iodine content. The aim of this work was to produce new data on the iodine content of the common edible mushrooms. The inorganic iodine contents of different wild...
Article
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Agaricus subrufescens Peck is a well-known Basidiomycota fungus (Royal Sun Agaricus), with rising demand in consumption and production worldwide. This particular mushroom with high medical value has been used successfully in cancer therapy and in the treatment of some bacterial and viral diseases. Four strains of A. subrufescens (Si2.2, 853, 1105,...
Chapter
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Bracken fern, Pteridium aquilinum (L.) Kuhn, is not only a worldwide distributed aggressive weed species, but it has great toxicological-eco-toxicological importance in medicine and veterinary medicine, based on its characteristic chemical composition. The plant has different secondary plant metabolites of potentially high biological activities. Co...
Article
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Bracken fern (Pteridium aquilinum) is the fifth most distributed common weed species of the world. Its ecological distribution is very wide, and the plant can grow and spread successfully on many types of soil. The cover of P. aquilinum is--in some cases--remarkable (e.g., in the United Kingdom). Bracken fern contains different poisonous agents: so...
Article
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The chitin contents of pileus and stipes of fruit bodies of Agaricus bisporus, Pleurotus ostreatus and Lentinula edodes (shii take) were determined and compared. The fruit bodies of different, common varieties of the cultivated mushroom species were taken from Hungarian and German large-scale farming. The analytical procedure was carried out on the...
Article
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Contents of 23 elements were estimated in pilei and stipes of different varieties of three cultivated mushrooms (Agaricus bisporus, Pleurotus ostreatus and Lentinula edodes). The average data of element's composition were evaluated and compared to each other and to the average composition of the wild growing fungi. The high and remarkable K (and pa...
Article
Basidiomes of 43 samples of eight Amanita species were gathered from different habitats of Hungary. The mineral composition (22 elements) was analysed by the ICP method in three independent replications, and mineral compositions found as discussed and compared. The Amanita species analysed were very different in As-, Cd-, Cr-, Mo-, Mn-, Se- and mai...
Article
Occurrence, content and biological role(s) of lithium in plant-, animal- and human tissues are partly understood, but information about Li levels of fungi (macrofungi) is practically absent. 171 samples of 38 common, edible wild mushroom species, originating from different localities in Hungary, were analysed. 44 samples had undetectable and 127 de...
Article
Production of cultivated mushrooms continues to increase at a high rate. The chemical composition of mushrooms is, therefore, of both scientific and practical importance. The mercury content of Agaricus bisporus (variety K-23), the most important cultivated mushroom species worldwide was investigated. The caps and stalks of the fruiting bodies, ori...
Article
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The review article writes about the toxicoses of indoor plant and garden plant origin - Amaryllis, Cyclamen, Bluebonnet, Four-o'clock, Gloriosa lily, Foxglove, Hydrangea, Hellebore, Hyacinth, Calla lily. Blue star. Lilies, Iris, Autumn crocus, Bird-of-paradise flower. Foxtail, Mother-in-law's tongue. Larkspur, Anemone, Bleedingheart, Coontie -, and...
Article
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One of the most poisonous species amongst higher plants is Conium maculatum. It is a very common nitrophile weed species, belonging to the Apiaceae (formerly Umbelliferae) family. It contains some piperidine alkaloids (coniine, N-methyl-coniine, conhydrine, pseudoconhydrine, gamma-coniceine), which are formed by the cyclisation of an eight-carbon c...
Article
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Selenium intake of the human population is very distinct and depends on the Se-content of consumed food. The higher intake of selenium can decrease the risk of many health problems in human and animal organisms. The main task of this work was to obtain new comparable data on Se content of Agaricus bisporus mushroom. The selenium content of differen...
Article
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The arsenic contents of 162 fruit body samples of 37 common edible mushroom taxa were analyzed. The samples were gathered from different habitats of Hungary (mainly from mountains) between 1984 and 1999. The arsenic content of the samples was measured by the inductively coupled plasma spectrometry method. Very low [lower than 0.05mg/kg dry matter (...
Article
Sodium contents of fruit bodies of some common edible mushroom species were analysed from the samples (total number: 153) gathered from different habitats of Hungary. The average sodium content of the different mushroom taxa varies between 100 and 400 ppm, and seems to be practically independent of habitat, nutrition type (saprotrophic, xylophagous...
Article
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A comparison of chemical constituents of fresh and conserved samples of Agaricus bisporus was made. The crude protein and crude fat contents were practically unchanged but a decrease in dry matter content and a remarkable decrease in ash content were found. The concentrations of some minerals (Cd, Mn, Zn) were unchanged, indicating that the solubil...
Article
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The author reviews frequent phytotoxicoses - Bean tree, Horse chestnut, False sago palm, Croton, Misletoe, Dieffenbachia, Monstera, Philodendron, Cuckoopint, Alocasia, Flamingo flowers, Holly, Lilly of the valley, Poinsettia, Daffodil, Oleander, Rhododendron, Monkshood, Yew, Tulip - in dogs and cats, summarizes the source, clinical signs and the po...
Article
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and Hygrophorus species, Craterellus cornucopioides, Gomphidius glutinosus, Macrolepiota rhacodes and Hydnum repandum. The inhibiting activities found were higher than those of cereals but lower than those of some fabaceous plants.
Article
The cyanogenic glycosides (CGs) are glycosidic derivatives of α-hydroxynitriles. These molecules are distributed in three phyla of higher plants; the majority of such compounds were isolated and described in dicot plants, and highest occurrence characterizes the subclass Rosidae. Biosynthetic capacity of CGs seems to be an ancient property in plant...
Article
Full-text available
The cyanogen glycosides belong to the products of secondary metabolism of plants. They are composed of an a-hydroxinitrile type aglycone and of a sugar moiety (mostly D-glucose). The distribution of the cyanogen glycosides in the plant kingdom is relatively wide, the number of glycoside-containing taxa is about 2500 (Taxa of Fabaceae, Rosaceae, Lin...
Article
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A lot of positive effects of some fungi (macrofungi) were and are used in the human medicine of some Asiatic countries (China, Thailand etc.). The historical background and some of the new results of the mycoterapy are summarised. The different nutritional benefits and biological effects of Agaricus bisporus, Lentinellus edodes, Pleurotus ostreatus...
Article
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The vanadium content of samples of 21 common, edible wild mushroom species was measured. The mushroom samples were gathered from different locations (habitats) of Hungarian forests and the analysis was performed with ICP. The V contents were found between 0 (i.e. under the detections limit) and 1 mg/kg d.m. Bioaccumulation of V was not found, the s...
Article
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The green plants fix a great amount of carbon (CO2) and accumulate as different organic molecules mainly as lignocelluloses. Fungi belong not only to an independent group of Eukaryots but they have – in most of the cases – a specific biochemical, physiological ability to decompose organic molecules, to produce substrates of respiration and to miner...
Article
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The vanadium content of samples of 21 common, edible wild mushroom species was measured. The mushroom samples were gathered from different locations (habitats) of Hungarian forests and the analysis was performed with ICP. The V contents were found between 0 (i.e. under the detections limit) and 1 mg/kg d.m. Bioaccumulation of V was not found, the s...
Article
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The review summarises the main groups of poisonous plants of Hungary. These poisonous plants may be grouped according to their toxic principles, an alternative and practical method of classification is based on the effect caused by the plants. The plants of the first group cause excitement and damage of central nervous system, the members of the se...
Article
The most poisonous mushroom toxins are produced by Amanita phalloides (death cap). The occurrence and chemistry of three groups of toxins (amatoxins, phallotoxins and virotoxins) are summarized. The concentration and distribution of toxins in certain species are variable, with the young fruit body containing lower, and the well-developed fungus hig...
Article
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Different chemical properties and biological effects of selenium are summarized. Natural selenium sources, the distribution and accumulation of this element in plants and fungi are not only chemical and phytochemical problems, but have a number of environmental and toxicological aspects too. The relative by high Se-accumulation of Boletus mushrooms...
Article
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Mercury is one of the most poisonous heavy metal which can be accumulated both in the environment and in different edible fungi. The first data on Hg-content of fungi were published in the seventies from different countries of the world. These investigations demonstrated the accumulations capacity of some fungal taxa (first of all Agaricus species)...
Article
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 The mercury (Hg) content of 112 samples of common, wild edible mushrooms was analysed by atomic absorption spectrometry. The average Hg content of all the samples was 1.72 mg/kg dry mass (DM) but the Hg concentrations found in different taxonomic groups (genera and species varied) remarkably. Although different sampling locations obviously have an...
Article
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Ninety three samples of twenty five higher mushroom species were analysed for chromium and nickel contents. The average Cr-content of the samples (gathered in years 1993-1995) was 1.43 mg/kg D.M., the concentrations varied between 0.05 and 4.51 mg/kg D.M. The highest Cr-content was found in Lactarius deliciosus, the smallest one in Tricholoma scalp...
Article
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The average zinc content of 363 mushroom samples collected form various locations in Hungary over a three-year period was 118.7 mg/kg dry wt. In 17 samples the zinc content was greater than 200 mg/kg dry wt. The greatest Zn content i.e. "accumulation" occurred in Russula atropurpurea samples (763-1067 mg/kg dry wt.). The mode of accumulation is yet...
Article
The average zinc content of 363 mushroom samples collected form various locations in Hungary over a three-year period was 118.7 mg/kg dry wt. In 17 samples the zinc content was greater than 200 mg/kg dry wt. The greatest Zn content i.e. “accumulation” occurred in Russula atropurpurea samples (763–1067 mg/kg dry wt.). The mode of accumulation is yet...
Article
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World wide about 200,000 tons of shii-take mushrooms (Lentinus edodes) are produced per year. Different positive biological effects are known (anticarcinogenic, anticholesterol, immunostimulating effects), but the mineral contents and amino acid composition of caps and stipes are still little investigated. The concentrations of minerals are in gene...
Article
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Different chemical components were analysed in the seeds and in testa of Vicia faba. The seeds contain a relatively high crude protein (27.5%), a low crude fat (3.36%) content; and the lignin concentration is low (2.65%). The testa of the seeds has a very high fibre concentration and is a significant Ca-source (1.86 g/kg). The higher macroelement c...
Article
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Weltweit werden jhrlich etwa 200000 t des Shii-take Pilzes (Lentinus edodes) produziert. Verschiedene positive, biologische Wirkungen sind bekannt (anticarcinogene, cholesterinsenkende Wirkungen und stimulierende Wirkungen auf das Immunsystem), aber die Mineralstoff- und Aminosuregehalte des Pilzes sind bislang nur wenig untersucht. Die Mineralstof...
Article
An HPLC method was used to separate and determine four isoflavone compounds (genistein, daidzein, formononetin, and biochanin A) from different parts (stem, leaf, and flower) of seven common Trifolium species. In general, low isoflavone concentrations were found in T. montanum, T. fragiferum, T. incarnatum, and T. repens, while T. alpestre, T. prat...
Article
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The chemical structure and main biological effects of higher mushrooms are summarised. The amanitins, phallotoxins (virotoxins), the giromitrin, muscarin, the toxins of Amanita pantherina, of Psilocybe species, the orrelanin, the coprin and the unidentified toxin of Paxillus invoulutus are discussed.
Article
The mineral elements of Agaricus bisporus and Pleurotus ostreatus (separately in the caps and stipes of the fruit body) were analysed. The main conclusions are: 1.1. The classical (conventional) and the new cultivation methods produce different mineral compositions in champignon. The new method (on pure wheat straw) produced lower B, Ca, Cu, Na, Zn...
Article
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Fifty six samples of edible, wide-spread species of higher fungi were analysed for copper-, manganese- and zinc-contents. The average copper concentration of the samples is high (56.16 mg/kg dry mass) as compared to the green plants. Some groups of fungi (Agaricus and Macrolepiota species) are considerable copper-accumulators (until 226 mg/kg DM)....
Article
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Der Kaliumgehalt von ebaren hheren Pilzarten betrgt durchschnittlich 34,35 g/kg–1 Trockenmasse (Standardabweichung: 12,91), er ist somit bedeutend und stellt eine wertvolle K-Quelle fr die menschliche Ernhrung dar. Die Kalium-Konzentration der Pilze ist relativ konstant. Eine Akkumulation von Kalium wird in den Proben nicht gefunden. Diese Tatsache...
Article
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56 Proben ebarer, verbreiteter Gropilzarten wurden auf Kupfer-, Mangan- und Zink-Gehalte analysiert. Die durchschnittliche Kupferkonzentration der Pilzproben (56,16 mg/kg Trockenmasse) ist relativ hoch (im Vergleich zu grnen Pflanzen), einige Pilzgruppen (Agaricus- undMacrolepiota-Arten) zeigen Kupfer-Akkumulation (bis 226 mg/kg). Ausgesprochene Ma...
Article
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The mineral elements and the amino acids in seeds of cultivated Amaranthus hypochondriacus were studied. The following conclusions can be made: 1. The contents of minerals in Amaranthus seed are similar to those of wheat and (except of a few elements: P, K) of pea. The habitats of plants, especially the soil conditions effect importantly on mineral...
Article
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Die Mineralstoffe und die Aminosu-rezusammensetzung der Samen von kultiviertemAmaranthus hypochondriacus wurden untersucht. Die Konzentrationen der Mineralstoffe inAmaranthus-Krnern sind hnlich denen in Weizen oder auch der Erbse. Die Standorte der Pflanzen haben allerdings einen bedeutenden Einflu. Der Gesamt-Aminosuregehalt und besonders die Meng...
Article
The arsenic and cadmium contents of 88 samples of mushrooms were determined. The majority of samples have a very low (practically zero) arsenic level; however, significant accumulations were found in the Agaricus species and in Macrolepiota rhacodes (which is related to the Agaricaceae family) and in three Tricholomataceae species (Flammulina velut...
Article
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The average potassium content of edible higher mushroom species is 34,35 g/kg-1 dry matter (SD: 12,91) and thus an important and valuable K-source for human diet. The K-concentration of mushrooms is relatively constant. An accumulation of potassium in the mushroom samples analysed was not found. This fact is confirmed by the results of other author...
Article
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The arsenic and cadmium contents of 88 macrofungi samples were determined. The majority of investigated samples have a very low (practically undemonstrable) level of arsenic; however accumulations were found in the Agaricus species and in the Macrolepiota rhacodes (family: Agaricaceae) and in two Tricholomataceae species (Lepista nuda, Clitocybe in...
Article
Certain species and genera of higher fungi possess the ability of bioaccumulation of certain elements. The high (in few cases extremely high) concentrations of cadmium, mercury, selenium, lead, vanadium, copper and arsenic in different taxons are demonstrated and possible mechanisms are noted and discussed.
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Different kinds of protein (crude, digestible, non-digestible) were analysed in caps and stipe of Pleurotus ostreatus (oyster mushroom) in four phases of development. The phases examined were: a (cap diameter < 5 cm); B (diameter 5-8 cm); C (diameter, 8-10 cm) and D (diameter > 10 cm). The Pleurotus variety analysed (the cap and the stipe) has a re...
Article
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The amino acid concentrations of six samples (five species) of the genus Russula and of seven samples (five species) of the genus Agaricus were determined. The Russula samples have significantly lower total amino acid concentrations (14.79% of the dry weight), than the Agaricus species (23.75%). Essential amino acids occur in both groups in appreci...
Article
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A comparative analysis of crude protein, crude ash, phosphorus (P), potassium (K) and calcium (Ca) contents of 57 samples of eight common edible mushroom species was made. The most important protein sources were: Marasmius oreades and Lepista nebularis. Species of the Boletaceae formed an intermediate group, while relatively proteinless species wer...
Article
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A comparative analysis of crude protein, crude ash, phosphorus (P), potassium (K) and calcium (Ca) contents of 57 samples of eight common edible mushroom species was made. The most important protein sources were:Marasmius oreades andLepista nebularis. Species of theBoletaceae formed an intermediate group, while relatively proteinless species were:A...
Article
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Die Aminosurezusammensetzungen von 6 Proben (5 Arten) der GattungRussula und von 7 Proben (5 Arten) der GattungAgaricus wurden bestimmt. Die Proben der GattungRussula(Tubling)-Arten haben eine Gesamtkonzentration von 14,79% (bezogen auf Trockengewicht), dieAgaricus-Proben (Champignon-Arten) haben eine hhere durchschnittliche Gesamtaminosurekonzentr...
Article
The different positive medicinal effects of certain fungi (first of all of higher ones) are reviewed. In the first part was summarized the fungus species used in the folks medicine, in the second a certain species of homeopathic treatments, finally the groups of fungi on the basis of their effects were described. Thus: one can distinguish the group...
Article
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Summary The chitin content of fruit bodies (in some cases caps and stipes) of some higher fungi from different parts of Hungary have been analysed. The following results were obtained. 1. TheAphyllophorales species which are xilophagous, wood-rotting fungi, have a lower chitin content. The other species (Boletales, Agaricales, Russulales) have a si...
Article
Die vergleichende Untersuchung der chemischen Zusammensetzung von Champignon-(Agaricus) und Austernseitling- (Pleurotus) Arten bzw. von ihren gezchteten Sorten erfolgte hinsichtlich 23 mineralischer Elemente. Aufgrund des Vergleiches der erzielten Ergebnisse konnte festgestellt werden: DieAgaricus-Arten erwiesen sich mit Ausnahme des gezchteten Cha...
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The authors carried out quantitative determinations of saponin content in papilionaceous-, grass- and other species of grasslands for 143 samples of a total of 80 species. Besides species of the genus Medicago (Medicago saliva, M. iupulina, M. falcala) saponin was measured in the species Anthyllis iiilneraria and A. macrocephala, and in all samples...
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The author analysed the steril tissue, isolated from the stem of tobacco (Nicotiana tabacum), grown 34 days on synthetic nutrient medium, supplemented by different amount of auxin. On the basis of data of fresh weight, dry matter, cell number and RNase activity after 34 days and after a short term auxin treatment in relation of RNase activity, it c...
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Various strains (D-13, F-1 and Pc-17) of champignon Agaricus bisporus (Lange, Singer) were cultivated with the small scale method of plastic bags on compost supplemented by different amounts of two bioactive substances (6-methyluracil and Ethrel) respectively. The average yield of the mushroom (kg/q compost), the dry matter (in per cent of fresh we...
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A terméshozamok növelése céljából kétféle hőkezeléssel (nedves, száraz) előállított szalma táptalajon dúsítási kísérletet végeztünk négy gombafajjal (Agaricus bisporus, Agaricus bitorquis, Pleurotus ostreatus, Lentinula edodes). A hőkezelt szalmához borsószalmát, szójaszalmát, lucernalisztet, buzakorpát és ProMycelt kevertünk 1, 2 és 3%-ban. A kísé...

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