Biomedical subjects

G Höflich

Publications and source records attributed to G Höflich.

31 records · Page 2Linked to original sources

PubMed1977

[The effect of biocides on the microflora of soils and their degradation. I. The selection of suitable biocides and ways of selective influences in soil-microorganisms (author's transl)].

The influence of 544 biocides on soil-microflora was investigated by a special plate-test and by a soil-test. Fungi were particularly sensitive to active substances. They were more inhibited by a greater number of substances, by lower concentrations and by a larger time-interval than bacteria. A differentiated sensitivity of fungi becomes apparent. The pseudomonads, a species of Agrobacter (AIA), flavobacteria and some coryneforme bacteria were relatively resistant. Actinomyces responded similar to fungi. The plate-test is suitable as preliminary test for the selection of substances retarding the degradation of straw. These organisms already favoured by treatments with active substance locate in higher quantities in such soils where the biological balance was disturbed in after the injection. Therefore, the effect of the active substance exceeds that of the injection. The displacement-effect by bacteria resistant to active substances and little active against cellulose plays a minor role in opposite to bacteria active against cellulose, because bacteria don't develop any homogeneous protective coat. A priority effect is therefore excluded.

Bacteria↗

PubMed1977

[The effect of biocides on the microflora of soils and their degradation. II. Correlations between a changed population of micro-organisms and the degradation of straw (author's transl)].

Fungi are of precedent importance for the decomposition of straw in comparison with bacteria and actinomycetes. Several genera and species are able to replace one another. For the fungi, by biocides easier reduced than other kinds of organisms, an inhibition of the decomposition of straw by application of fungicides is possible. An unrestricted or promoted flora of bacteria is not able to replace a restricted flora of fungi. The decomposition of straw cannot be stopped completely. Certain types of fungi locate in higher quantities as a result of the elimination of the competition by bacteria and in dependence on the used antibiotic. Then the special intensity of the decomposition of straw depends on the cellulase-activity of the in each case located fungi. In order to stop the decomposition of straw completely it is necessary to inhibit both the physiologically active bacteria (pseudomonads and bacteria) and the fungi for a longer period of time. Combinations of bactericides and fungicides can bring about synergistic decomposition retarding effects. A persistent stimulation of the straw-decomposition by application of active substances was not successful.

Actinomycetales↗

PubMed1977

[The effect of biocides on the microflora of soils and their degradation. 3. Interactions between modified populations of micro-organisms and the decomposition of plants for green-manure in comparison to the decomposition of straw (author's transl)].

The possibilities to influence the decomposition of straw and lucerne by fungicidal, bactericida and total acting microbiocides, respectively, were tested comparatively. Total or fungicidal acting substances caused the heaviest inhibition of decomposition at both the organic matters. The efficiency of active ingredients was greater at straw than at lucerne. The reason of the different inhibiting effects is that the lucerne which is easy to decompose and rich in protein can be decomposed alone by the physiologically active bacteria, which are resistant to active ingredients. That means the decomposition of lucerne takes place without the help of fungi. However, the fungi sensible to the active ingredients play a more important role in the straw decomposition. Therefore substances with permanent fungicidal effects are sufficient for the inhibition of straw decomposition. Inhibiting the decomposition of greenmanure presumes permanent acting fungicidal and bactericidal substances. Such substances are not available at present. Systemic fungicides did not influence the decomposition of plants for green-manure due to their limited scope of activity.

Anti-Bacterial Agents↗

PubMed1977

[The effect of biocides on the microflora of soils and their degradation. 4. The influence of substances inhibiting the straw decomposition on the nitrogen transformation (author's transl)].

1. Active ingredients retarding the carbon-transformation of straw (TCP, Thiuram, TBTO) also retard the nitrification. Their active period depends on the concentration and on the presence of organic matter. High doses of urea can inhibit the nitrification as well. 2. The activity of urease and the ammonification could not be influenced by adequate doses of the tested active ingredients. 3. The species of bacterium Azotobacter fixing the nitrogen from the air were inhibited by TCP, urea and D-chloramphenicol and promoted by Thiuram and WTZ II 277 after a short period of inhibition. 4. The fungi are very important in the biological nitrogen fixation after manuring straw and in prevention of nitrogen leaching in the autumn. 5. The sufficient concentration of the active ingredients to inhibit the nitrification are lower than the fungicidal concentrations. The soil bacteria could even not be restrained by doses of 5000 ppm. The bacilli were more retarded in presence of organic matters than in a not manured soil.

Ammonia↗

PubMed1975