Mutagenic and tumourigenic properties of the spores of Aspergillus clavatus

Abstract

Summary.-Spore walls of a sputum-derived isolate of Aspergillus clavatus yielded mutagen(s) when their extracts were fractionally precipitated with ethanol following alkaline hydrolysis. After spores were given by nasal inoculation to 6-8-week-old CF-i mice, light and electron microscopy of lung sections showed that they had been readily phagocytozed by the polymorphonuclear leucocytes and alveolar macrophages mobilized during early allergic alveolitis in immunized mice. The formation of phagosomes was followed in thioglycollate-stimulated peritoneal macrophages grown in vitro. Unimmunised mice showed a comparable lung reaction, attributed to pulmonary mycotoxicosis, and revealed a rising incidence of lung tumours, from 25% at 2 months from inoculation, to 27.3% at 6 and to 55.5o% at 8. Mean numbers of tumours per lung rose from 1-0 to 2-2. Total tumours, including lymphomas, reached a final incidence of 77.7o% at 8 months, when control animals were tumourfree. Tumour development correlated with the retention of apparently intact spores within giant cells probably derived from aggregates of alveolar macrophages. The implications of these findings in the light of the known history of human exposure to such spores is discussed.

Discovery of a sexual cycle in Aspergillus clavatus

“…8,9 Its spores are carcinogenic in mouse lung. 10 A. clavatus is also an economically important species because it can grow on rotting fruit (especially apples) and stored food products (mainly cereal grains) with high moisture content e.g. inadequately stored rice, corn and millet 2,3 and their malts (germinated seeds) including barley, maize and sorghum, as well as other stored feedstuffs, including legume seeds.…”

Aspergillus clavatus tremorgenic neurotoxicosis in cattle fed sprouted grains

“…1,2 Its spores are carcinogenic in mouse lung. 3 A tremorgenic mycotoxicosis from eating sprouted grain infested with A clavatus has been described in ruminants in Europe, South Africa, China, Israel and Brazil. [4][5][6][7][8][9][10][11] Sprouted grains of barley, wheat, sorghum, and maize have been involved.…”

The Genus Aspergillus

“…Mutagenicity of alkaline hydrolysates of A. clavatus has been demonstrated, and in laboratory mice pulmonary tumours developed after nasal administration of spores (Blyth and Hardy, 1982).…”