Fatal Chaetomium cerebritis in a bone marrow transplant patient.

The number of opportunistic infections in the central nervous system (CNS) has been steadily increasing because of a rising number of immunocompromised patients. A rare form of CNS infection can be caused by Chaetomium species, one of the largest genera of saprophytic ascomycetes. The CNS lesions in the present case were caused by Chaetomium atrobrunneum. The main characteristic of almost all Chaetomium species is presence of hairs or setae covering the ascomata. Microbiological studies are the only definitive way to correctly identify this fungal organism. The rapid evolvement of the cerebral infection suggests that the brain tissue provides a favorable environment for growth and proliferation of these fungi. This is the second documented case of a fatal brain abscess caused by Chaetomium atrobrunneum, and the first case report in a bone marrow transplant patient.

Production of cytokinin-like substances by mycorrhizal fungi of pine (Pinus sylvestris L.) in cultures with and without metabolites of actinomycetes.

Studies on the effect of post culture liquids of actinomycetes on cytokinin-like substances production by mycorrhizal fungi have revealed that actinomycete metabolites inhibited or stimulated the synthesis of these compounds. The results of chromatographic analyses suggest, that substances stimulating the soybean callus are likely to be: riboside 6 (gamma, gamma-dimethylallylamino) purine and riboside zeatin. Using gas chromatography it was confirmed that both substances are produced by Rhizopogon luteolus. Paxillus involutus synthesizes probably besides the two substances also zeatin, as appears from the data obtained by column chromatography.

Effect of pH on production of cytokinin-like substances by bacteria isolated from soil, rhizosphere and mycorrhizosphere of pine (Pinus silvestris L.).

Cytokinin-like substances were produced in higher amounts by soil isolates than by those isolated from the rhizosphere and mycorrhizosphere. However more bacterial strains isolated from the rhizosphere and mycorrhizosphere were capable of synthesizing cytokinin-like compounds. A distinct effect of pH on the production of these substances was found. It is suggested that zeatin and zeatin riboside are likely to be among the cytokinin-like substances detected.

The synthesis of cytokinin-like substances by coryneform bacteria isolated from the roots of pine seedlings (Pinus silvestris L.).

Seven of ten strains studied produced cytokinin-like substances, mainly in 7 day old cultures. The cytokinin-like substances were most often located on chromatograms at Rf values 0.8 to 0.9, rarely at Rf 0.6 to 0.7.

Synthesis of auxins by fungi isolated from the roots of pine seedings (Pinus silvestris L.) and from soil.

Synthesis of auxins by fungi grown with and without tryptophan has been studied. 26 out of 30 fungal strains produced detectable amounts of auxins in tryptophan contain media. 18 strains produced but very small amounts of auxins in media without this amino acid. By means of paper chromatography, chromogenic reagents and biotest three active substances could be distinguished. They were found on the chromatograms run with isopropanol, ammonia, water (10:1:1 v/v) at Rf 0.05--0.2, 0.3--0.5 and 0.8--1.0. Most strains produced active substances with Rf 0.3--0.5.

Production of auxins by bacteria isolated from the roots of pine seedlings (Pinus silvestris L.).

Qualitative and quantitative studies were carried out on the production of auxins by Coryneform bacteria, the only bacterial types isolated from roots of pine seedlings. Almost all isolates were capable of producing auxins in tryptophan containing media. In media without this amino acid only trace or no auxins were produced. Most of the bacteria studied synthesized auxins located on the chromatograms run with isopropanol, ammonia, water (10:1:1 v/v) at Rf 0.3--0.5. Moreover substances with Rf values 0.05--0.2 and 0.8--1.0 were produced by some strains. No plant growth inhibitors detected with the Avena coleoptiles biotest were produced by the bacteria studied.

Production of gibberellin-like substances by bacteria and fungi isolated from the roots of pine seedlings (Pinus silvestris L.).

The production of gibberellin-like substances by bacteria and fungi was investigated. A considerable number of the microorganisms studied produced these substances (55 and 86% of bacterial and fungal isolates respectively). Most of the organisms tested synthesized biologically active substances located on the chromatograms with the solvent system benzene, acetic acid (10:3 v/v) at Rf 0.05--0.3. The ammount of gibberellin-like substances produced varied in the range 0.00007--0.00065 GA3 equivalents mug/ml in bacteria and 0.00014--0.00118 mug/ml in fungi.