17 
the proper control (following the time course of death without thymine 
after 20 hours) was not included in the presentation. 
c) Thymineless death does not occur at high cell densities and 
death at low densities appears to cease after 8 to 12 hours of starvation 
(Curtiss jrt al. , Figure 20). This phenotype may not be expressed in 
environments where cell density is high, such as in human individuals who 
have a high concentration of bacteria in the gut, or as in densely 
populated raw sewage. 
§10. Thymineless DAP-less death: 
a) Thymineless death and DAP-less death phenotypes do not act 
cooperatively or synergistically in that the death rate under combined 
starvation conditions is similar to the rate of death during either DAP 
or thymine starvation conditions singly in all media tested excepting 
supplemented ML (Curtiss jrt jQ. , Figure 19). 
b) Although slow regrowth of cultures was not observed under 
this "test of fire", under the most minimal of conditions tested, greater 
than 1.0% of both Xl??6 and X1876 survived up to 36 hours of starvation 
(Curtiss e_t al^. , Figure 22). 
c) In addition, whereas X1776 died out almost completely by 
zxo nours (9 days), 0.1% of X1876 survived for 9 days in the most minimal 
of nutrient starvation media tested (ML + Glc, Thr, Met, Bio, Lys). The 
addition of the suplemental piece of DNA (pSClOl) into yl776 enables the 
strain to survive much better under starvation conditions. 
d) This evidence (§10c, immediately above) is the first direct 
evidence presented demonstrating that the addition of a supplemental piece 
of DNA into the yl776 disarmed host improves the viability of that host 
[Appendix C — 205] 
