8 
Ms. Hunt said organism survival was calculated in percent biological recovery, 
a ratio of percent viable rec every and percent physical recovery. The fluores- 
cent tracer uranine was added to the bacterial suspension before aerosol izat ion 
as a control to calculate physical loss. The uranine was also collected in 
all qlass impinqer (AGI) samplers and analyzed by a fluoremeter. 
Ms. Hunt then presented data generated at 45 percent relative humidity and 
room temperature. She said samples of aerosolized organisms were taken at 
two, five, ten, arrJ thirty minutes after aerosolization. As might be expected, 
the wild-type strain. Eh coli CS10, survived better than both Eh subtilis 
BR151 and Eh coli HB101. Eh subtilis BR151 and BR151-pHV14 survived aerosoli- 
zation somewhat better than E. coli HB101 although this was not statistically 
siernificant. BR151 survived aerosolization better than BR15l-pHV14. 
At 45 percent humidity and room tonperature, Eh_ coli HB101 rapidly decreased 
within the first few minutes after aerosolization. In fact, no viable Ek_ coli 
HB101 oraanisms were detected after five minutes following aerosolization. 
However, HB.lOl-pBIRBT survived better than HB101, with small but detectable 
levels of HBlOl-pBRffo observable after 30 minutes following aerosolization. 
Ms. Hunt then presented data generated at 70 percent relative humidity and 
room temperature . At 70 percent relative humidity, there was no significant 
difference between the aerosol survival of the wild- type Eh_ coli CS10 and 
HB]01 for up to 30 minutes after aerosolization. However, Eh_ coli HBlOl-pBRfiT, 
survived siqnificantly better than Eh_ coli HB101 and wild-type Eh_ coli CS10 
for up to the 30 minutes after aerosolization. 
Ms. Hunt hypothesized that perhaps pBF$T may code for excretion of beta tubulin 
to the periplasmic space, as the pBR-322 plasmid expresses ampicillin resistance 
by excretion of beta lactamase to the periplasmic space, and the cDNA encoding 
for beta tubulin is inserted within the ampicillin resistance gene. If beta 
tubulin is excreted to this space, its presence may protect the organism. 
Alternatively she suggested that as pBR T expresses tetracycline resistance, 
the appearance of additional membrane proteins of 14,000, 17,000, and 34,000 
daltons associated with tetracycline resistance may affect membrane structure 
and stability. A recent Russian study demonstrated increased aerosol survival of 
E. coli K-12 after transfer of the pSA-50 plasmid into the organism. The study^ 
correlated increased survival to appearance in the outer membrane of two pro- 
teins of molecular weights of 70,000 and 80,000 daltons encoded by the plasmid. 
Ms. Hunt said the E. coli strains were examined for retention of plasmid func- 
tion after aerosolization at 70 percent relative humidity. Aerosolized E. 
coli HRIOl-pBRBT were sampled and grown on media either containing (tet + ) 
^Koniukhov , v. G., M. E. Liaiman, L. Likhoded, and L. A. Maltseva, 1982. Analysis 
of the basic protein fractions of the outer membrane in Eb_ coli strains differing 
in survivability in air. Zh. Mikrobiol . Epidemiol. Immunobiol. 1:54-58. [English 
Abstract! . 
[ 344 ] 
