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101.
Progesterone transformations as a diagnostic feature in the generaAlternaria,Stemphylium andCladosporium 总被引:1,自引:1,他引:0
Various species of the generaAlternaria, Stemphylium andCladosporium were shown to display a specific reaction characteristic for the given genus. In theAlternaria genus this is a 1-2-dehydrogenation of the A ring of the steroid molecule, inStemphylium 14α-hydroxylation and inCladosporium 7β-hydroxylation. This chemotaxonomic feature may supplement morphological and functional criteria in the taxonomy of filamentous fungi (Hyphomycetes). 相似文献
102.
Regression analysis of the spontaneous spike activity of neurons in Helix pomatia was carried out with the aim to establish the statistical parameters of this activity under constant experimental conditions and during longer time intervals. The activity of 38 randomly chosen neurons in visceral and parietal ganglia, penetrated by microelectrodes and activated either endogenously by pacemaker potentials or by synaptic inputs, was recorded during time intervals lasting from 20 min to 3 h. The main results of the statistical analyses are presented in the table where the parameters of both cell types are listed. The validity of the regression analysis applied here is discussed from the point of the possibility it offers for carrying on the data processing quickly and without applying complex calculating means. The results are also considered regarding the current interest of our research group. 相似文献
103.
104.
Ethylene was collected in methanol solution of mercuric acetate and the addition compound formed was then separated by means of paper chromatography. The spot area and colour intensity after detection were determined using a densitometer. The amount of collected ethylene was calculated from a calibration curve. The ethylene liberated from plant samples was collected during one or two days. During this period the amputation of the whole plant organs did not influence ethylene production. Changes in ethylene production were found after segmentation of the tissue or after the treatment with auxin and Co2+ ions. The above-ground parts of investigated herbs released 0.3 to 3.5 μl of ethylene per kg fresh weight per hour. The leaves of investigated trees released 1 to 20 μl of ethylene per kg f.w. per hour. The rate of the production of ethylene seems to be specific for a given species. 相似文献
105.
106.
It was found that ethionine partially inhibits the transport of the inducer (TMG) of β-galactosidase into the cells ofEscherichia coli ML-30. The synthesis of β-galactosidase-specific messenger RNA is not inhibited. Ethionine appears to be incorporated into
proteins synthesized by the strains used. The incorporation of ethionine into the molecule of β-galactosidase results in the
synthesis of an enzymically inactive, immunologically cross-reacting protein. 相似文献
107.
Manometric studies were carried out on the respiratory activity of different rhizosphere and non-rhizosphere soils to follow
quantitatively the over-all microbial activity in the rhizosphere soil as affected by the species and growth phase of plant.
Oxygen consumption was distinctly greater in rhizosphere soils as compared to that in non-rhizosphere soils. The difference
between oxygen consumption by rhizosphere and non-rhizosphere soils changed with the course of plant growth and it was not
the same in different plants. This difference in oxygen consumption might be a measure of the amount of available oxidizable
substrate in the rhizosphere. A rhizosphere sample had greater diversity as well as higher concentration of free amino acids
than a non-rhizosphere sample of the same soil. Bacterial counts pointed to preferential stimulation in the rhizosphere of
bacteria requiring individual amino acids. amino acids, such as glycine, alanine, asparsic acid of tyrosine were oxidized
more rapidly in rhizosphere than in non-rhizosphere soil, but the extsent of oxidation for each of the amino acids studied
did not differ. The amount of oxygen consumed during oxidation of alanine, aspartic acid or tyrosine was about one-half of
the total amount necessary for complete oxidation. With glycine a higher extent of oxidation (60%) was observed. These extents
of oxidation of glycine and aspartic acid did not change on investigation at two different phases of plant growth. 相似文献
108.
109.
The virus origin of a Czechoslovak isolate of potato witches' broom disease is discounted: electron micrographs of ultrathin section of phloem tissues from plants infected with potato witches' broom disease demonstratedMycoplasma-like bodies, spherical or elongated showing binary fission and fragmentation. The minute corpuscles have a diameter of about 50–60 nm, the largest bodies of 1000 nm. The width of elongated filamentous structures is about 200 nm, most oval bodies have a diameter of 250 nm. A weak tetracycline treatment of diseased plants causes a delay of symptom development; a strong dose of tetracycline (applied by means of the wick method into the stem) inhibits symptom appearance completely. Tetracycline produces a phytotoxic effect inhibiting the growth of tomato plants and causing (at higher concentrations) necrosis and death of these plants. There is a note in the paper dealing with the term “mycoplasma”. The word mycoplasma in the sense ofEriksson (1897) or ofMereschkowsky (1910) does not correspond to the genus nameMycoplasma Nowak (1929). 相似文献
110.
Milena Riesová-Kučerová 《Biologia Plantarum》1969,11(5):338-346
The dependence of the frequency of recessive lethal (two groups), chlorophyll and morphological mutations on the mutagen concentration was determined in M2 after subjection to N-nitroso-N-methylurea applied to seeds ofArabidopsis in three concentrations (0·05, 0·10 and 0·20mm). The observed frequencies were compared with the theoretically expected ones for the linear and for two exponential types of dependence, by using the t-test, according to the formulas m=k. C, m=k. C3/2, m=k. C2. No satisfactory agreement with any expected type of dependence was found when directly observed frequencies were used. Since a considerable deficit of mutation frequency was observed in high concentrations, the correction of frequency values was done with respect to the probability of occurence of double mutations. After such a correction, a clear exponential relation was found in both types of lethals and a linear one in chlorophyll and morphological mutations. The probable occurence of multiple mutations should be, therefore, taken into account if the dependence of mutation frequency on the concentration of mutagen is discussed. 相似文献