FEBkUARY 15-16 - MINUTES OF MEETING 
5 
"N. crassa and S. cerevisiae as HV1 systems. Specified 
strains of N. cr assa which have been modified to prevent 
aerial dispersion and unmodified laboratory strains of 
S. cerevisiae are acceptable as HVl systems based on 
their natural containment. The following N. crassa 
strains can be used: 
(1) ini (inositolless) strains 37102, 37401, 46316, 
64001 and 89601. 
(2) csp-1 strain UCLA 37 and csp-2 strains FS 590, 
UCLA101 (these are conidial separation mutants). 
(3) eas strain UCLA191 (an "easily wettable" mutant)." 
This section of the report was discussed and some of the advantages 
of using the lower eukaryote host-vector systems were described. 
The organisms are structurally and genetically more related to the 
cells of higher eukaryotes and there is the possibility of obtain- 
ing gene expression that may not occur in E. coli , particularly due 
to possibility of processing intervening sequences. The extensive 
knowledge of the genetics of Saccharomyces and Neurospora will 
enable significant contributions by investigators who have worked 
extensively with these organisms. 
It was explained that the basis for proposing these organisms for 
HVl containment came from considerations of the modes of excape, 
the opportunity for establishment in nature, and the possibility 
of transferring cloned segments to other species or strains in 
nature. As discussed in the report, there is very little oppor- 
tunity to mate with other strains or species in nature and, 
furthermore, there are no natural vectors known which might 
effect interspecific transfer of genetic material. 
Saccharomyces cerevisiae and Neurospora crassa are nonpathogenic 
to man, animals and plants, and not closely related to known 
pathogens. Therefore, relevant and important experiments could 
be done safely without risk to man, animals, plants or the general 
environment. The ecological niche for cerevisiae is the 
surface of fruits or the nectar of f lcwers . N. crassa is found 
abundantly at barren, burned-out sites in the semi-tropics. 
Neither organism can colonize the gut of man. Large amounts of 
bread and beer are consumed without any pathogenic effects of 
the yeast that are present. 
Dr. Gottesman said that she supported the proposal as these organ- 
isms are not pathogens and yeast does not have the usual escape 
[ 51 ] 
