Schizothecium keniense — a new fungus from cow dung

Schizothecium keniense is a coprophilous fungus, that is, one associated with the dung of herbivores. The material came from cow dung collected near the campus of Egerton University in Kenya. The fruiting bodies were immersed in the substrate and broke through its surface. In their upper part they bore clusters of agglutinated, swollen hairs, a character typical of the genus Schizothecium. The dark upper cell of the spore had a germ pore, and the lower one was pale and narrow.

The material was isolated in pure culture, designated CCF 6931 and YMF 175. The culture did not sporulate, so the description of the sexual structures was based on the specimen from dung, preserved in the PRM herbarium under number 964937. The authors examined growth on several media and a range of temperatures: a minimum of about 8°C, an optimum of 25°C and a maximum of 28°C. The phylogeny used ITS, LSU, rpb2 and tub2.

The name was registered in MycoBank under the number MB 862939, and the formal authorship reads Y. Marín & K. Harms. The epithet keniense refers to the country of origin. The paper under DOI 10.3897/mycokeys.136.191424 combined taxonomy with a study of metabolites. Among other compounds, a new one named pyrrospirone Z and related decahydrofluorene alkaloids were isolated from the culture.

Detecting activity of a compound in laboratory tests does not amount to a finished antibiotic or a medicine. An in vitro result is a first stage that requires confirmation of mechanism, toxicity, dose and action in an organism. Nor does origin in dung make the fungus dangerous to people; the publication does not present it as a pathogen.

The species shows that a short-lived substrate can hold rich and poorly known diversity. Collecting requires a record of the host, the place and the state of the material, and culture preserves the possibility of further study. Assessing range and threat is not currently possible on the basis of a single known origin.

The specimen and the culture play different roles. The herbarium preserves the structures on which the diagnosis was based, while the living strain allows sequencing, growth tests and chemical analyses to be repeated. Results should always cite the deposit number, so that an experiment concerns the same material. Further isolates from other hosts and regions will show whether the metabolite characters are stable for the species or peculiar to one strain and its culture conditions.

What the paper establishes

Schizothecium keniense was described from cow dung collected near Egerton University, Kenya. Holotype PRM 964937 preserves sexual structures, whereas living culture CCF 6931/YMF 175 did not sporulate; ITS, LSU, rpb2 and tub2 supported its placement. MycoBank: MB 862939. Culture growth was optimal at 25°C, but one isolate cannot define the species' niche or range. The cow is not a host in a parasitic sense: dung is the coprophilous substrate. The culture yielded the new pyrrospirone Z and related compounds. Some inhibited selected Gram-positive bacteria in vitro or were cytotoxic to tested cancer-cell lines. These are plate-based compound screens, not evidence of a safe or effective medicine.