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H Korth

Publications and source records attributed to H Korth.

At least 19 recordsLinked to original sources
PubMed1993

Pseudomonas fluorescens var. aluphilia--the influence of Al3+ on the growth rate and formation of phenazines.

The thin-layer chromatographic characterization of phenazine derivatives formed by a subspecies of Pseudomonas fluorescens under iron deficiency conditions in the presence of Al3+ showed that regarding type and quantity they were relatively different from phenazines generated on the basis of Be(2+)-containing culture media or containing neither Be2+ ions nor Al3+ ions. A comparison has shown that bacterial synthesis of phenazine derivatives is stimulated more by Be2+ ions than by Al3+ ions.

Aluminum↗
PubMed1990

Isolation of Pseudomonas fluorescens producing phenazine derivatives exclusively under strains conditions of iron deficiency.

We succeeded in isolating biotypes of Pseudomonas fluorescens forming phenazine derivatives exclusively under conditions iron deficiency. A culture medium containing traces of beryllium with glucose as the only carbon source allowed these microorganisms to grow under production of a brilliant red colour. Without beryllium the colonies were brown in colour. Spectroscopic investigations showed the red pigment to be a mixture of di- and trihydroxyphenazine carboxylic acid. UV/VIS measurements of the culture medium indicated the additional presence of ironcomplexing proferro-rosamines.

Beryllium↗
PubMed1986

[Not Available].

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Equipment and Supplies↗
PubMed1984

Breath hydrogen as a test for gastrointestinal transit.

Intestinal transit is an important indicator of small-bowel function. This study served to investigate oro-cecal and duodeno-cecal transit times of different carbohydrate test meals and to evaluate intra- and interindividual variability of the breath hydrogen test. Breath hydrogen was analysed by an electrochemical cell in 25 healthy volunteers. Oro-cecal transit time of lactulose was much shorter than that of a standardized normal test meal. Duodeno-cecal transit was approximately one hour shorter than oro-cecal transit. Considerable intra- and interindividual differences were observed. It is concluded that results of lactulose test meals do not permit conclusions as to the physiological situation. Large intra- and interindividual variability of transit times must be taken into account in any study using the breath hydrogen test.

Adult↗
PubMed1982

[Isolation of an antibacterial active tropolone from a Pseudomonas cepacia strain].

In the strain ATCC 17759 of Pseudomonas cepacia a highly antibacterial active substance was found, which could be identified as the tropolone bis-(3-hydroxy-2-oxocyclo-heptatrien-(3,5,7)-yl)-sulfide. This data confirm that tropolones are not only found in plants like western red cedars, but are also occurring as metabolites in bacteria. At least in Pseudomonas cepacia there seems to be an interesting reciprocal correlation between the production of tropolones and of phenacines. The purified tropolone showed a broad antibacterial activity spectrum against gram-positive and gram-negative microorganisms. The MIC-values were situated between 12.5 and greater than 100,0 microgram/ml.

Cycloheptanes↗
PubMed1979

[Differentiation of Klebsiella pneumoniae variatio "oxytoca" (author's transl)].

Altogether 268 strains of Klebsiella were investigated with respect to their ability to ferment dulcitol and to produce indole, gelatinase, and brown pigment on a medium containing gluconate and ferric citrate. In addition the capacity of the strains to use m-hydroxybenzoic acid as sole source of carbon and energy was tested. Of the 83 indole-positive Klebsiella strains 72 (87%) were able to grow on the m-hydroxybenzoic acid medium, whereas only 2 (1%) of the indole-negative strains did so. Late liquefaction of gelatin occurred in 66 (80%) of the indole-positive strains. The ability of the indole-positive Klebsiella strains to use m-hydroxybenzoic acid as sole carbon source supports the view that these strains should be grouped in a separate taxon, which may be named Klebsiella oxytoca; it also provides a simple additional test for the identification of these strains.

Fermentation↗
PubMed1971

Pigment formation for differentiating Cryptococcus neoformans from Candida albicans.

When 2,3- or 3,4-dihydroxybenzoic acid, 3,4-dihydroxyphenylalanine, and 3,4-dihydroxycinnamic acid are added to growth media, they are converted to a characteristic brown pigment by Cryptococcus neoformans. This pigment formation has hitherto been encountered only when this microorganism was cultivated on media containing Guizotia abyssinica seed. This phenomenon can be used for differentiating Cryptococcus neoformans from Candida albicans. Possible precursors of these o-diphenols (quinic acid, aromatic monohydroxy acids, or tyrosine) do not give rise to the brown pigmentation.

Agar↗