Identification of spores in the polycentric anaerobic gut fungi which enhance their ability to survive.

Two new isolates of the gut fungi were obtained from the rumen digesta and faeces of a cow. These isolates, designated Anaeromyces following rDNA typing, displayed a polycentric growth habit but differed from all other gut fungi in that they were able to survive in the laboratory for considerable periods without the need for sub-culture. Light microscopy of preparations from old liquid-grown cultures revealed the presence of DNA-containing spores with two or four chambers. A comparative evaluation of the growth produced when fresh media were inoculated with a sample originating from young or old cultures revealed that active growth was delayed with the inoculum from the older culture. We propose that the chambered spores observed in these cultures provide an alternative path in the life cycle of these fungi and may function as a resting stage within the anaerobic environment of the herbivore gut.