Antibiotic Production by the Microfungi of Acid Heath Soils

Abstract

SUMMARY: A study has been made, using a plating technique, of the fungi occurring in acid sandy podsol soils and of their distribution at different levels of the soil profile. The most widespread species, characteristic of this type of soil, included: Absidia orchidis, Mortierella alpina, Mucor ramannianus, Penicillium frequentans, P. nigricans, P. roqueforti, P. terlikmshii and Tricho-a wiride. A number of other species were locally abundant, including Absidia glauca, Coniothyrium sp., Gliocladium sp. (roseum series), Penicillium citrinum and Zygorhyncus nmellem'.The plate counts of viable fungal units decreased sharply from upper to lower levels, though there was occasionally a secondary maximum in the upper part of the B horizon. Most species were characteristically found most abundantly in upper layers of the A horizon, but Mucor ramannianus was notable for its abundance a t much lower levels ; in several of the profiles examined it was isolated in almost pure culture from the B horizon.Of the sixty-five species isolated, about half produced antibiotics. Most of these were toxic to fungi and bacteria; only a few cases of specific antifungal or antibacterial activity were encountered. The Phycomycetes differed from other groups in that none produced antifungal substances. The capacity to produce antifungal antibiotics appears to be correlated with the distribution of species; of the widespread and locally abundant fungi, 45% produced such antibiotics as compared with 15 yo of the rare fungi. Nevertheless, certain widespread species (e.g. Absidia orchidis, Mortierella alpina, Mucor ramannianus, Penieillium roqueforti) did not produce antifungal antibiotics, so it cannot be considered to be a necessary character of widespread soil fungi. There is some evidence that such widespread non-producers of antibiotics are relatively resistant to the antibiotics produced by other species.An attempt has been made to group the fungi isolated into Burges' ecological categories of 'sugar-fungi' and 'humus-fungi' on the basis of their capacity to attack and utilize carboxymethylcellulose (CMC). Only 26 % of the fungi were unable to utilize CMC, Phycomycetes being prominent among these. Whereas 35 yo of the rare fungi and 54% of locally abundant fungi were 'sugar-fungi', only 17% (all Phycomycetes) of the widespread fungi were ' sugar-fungi'.These results are believed to lend support to the view that antibiotic production is of ecological significance to soil fungi. They also provide information which can form the basis of an experimental search for more direct evidence.

Soil Microfungal Changes among the Profiles of Disturbed Conifer-Hardwood Forests

“…Although this pattern has been proposed by other investigators working with different vegetational communities, their conclusions were based primarily on subjective evaluation of species lists (Jeffereys et al 1953, Chase and Baker 1954, McLennan and Ducker 1954, Sewell 1959, Burges 1958, Warcup 1957, Parkinson and Balassoria 1967. A somewhat unexpected result was the sequence in which the popula- tions were segregated along the first axis.…”

AXENIC SYNTHESIS OF ERICOID MYCORRHIZA IN VACCINIUM ANGUSTIFOLIUM AIT. BY OIDIODENDRON SPECIES

“…The ability of three of the five species to produce typical ericoid mycorrhizas on Vaccinium seedlings suggests that the role of some soil fungi may differ depending on environmental factors. O. cerealis and O. griseum, for example, in addition to being root endophytes are good cellulose decomposers (Robak, 1932;Jefferys et al, 1953;Mangenot, 1952).…”

Antifungal properties of silver nanoparticles against indoor mould growth

“…Mortierella isabellina has been applied in various regio-and stereospecific biotransformations. Mortierella wolfii is reported as an animal pathogen causing bovine mycotic abortion, pneumonia and systemic mycosis (Certik and Shimizu, 1999;Domsch et al, 1980;Dyal and Narine, 2005;Jefferys et al, 1953). Information provided by the Occupational Safety & Health Administration of the United States Department of Labor states that the Mortierella species might cause certain health effects such as: allergies, irritation, hypersensitivity pneumonitis, and dermatitis.…”