Figure 1 : Frequency of plasmid molecular weights in sewage effluent (SE), sewage
outfall (SO), Ocean City (OC), and clean water (CW) strains.
The results of the experiment designed to transfer the 34 Mdal plasmid back into the
cured derivative strain of SB23 were inconclusive. Plasmid DNA could not be detected in
the transformed cells, even though clearing was observed around the colonies two to four
days after cells undergoing transformation treatment were spread-inoculated onto
phenanthrene-layered agar plates. Lack of detection of the plasmid DNA suggests that
integration of the plasmid into the chromosome may have occurred, as one possible
explanation for this finding.
After 2 days
After 7 days
Strains
DPM*
% of total DPM
DPM
% of Total DPM
above control
above control
Control
223
0.00
718
0.00
E. coli HB101
290.83
0.62 = 0.01
693.93
-0.22 = 0.01
Flavobacterium sp.
SB23 cured
286.33
0.58 = 0.05
581.5
-1.24 = 1.43
Flavobacterium sp.
SB23 (pG05) parent
391.67
1.50 = 0.1
1295.7
5.25 = 0.13
Table 2 : Radiolabeled (
14 C-) Penanthrene Metabolism. * mean DPM (disintegrations per minute) for three
replicate vials.
Flavobacterium sp. SB23 (pG05), known to clear phenanthrene agar, and cured dervivative (non-phenanthrene clearing) strain were tested for their abilities to metabolize (9
-
14 C)-phenanthrene as sole source of carbon and energy (Table 2). While E. coli HB101, a
strain not known to degrade phenanthrene, yielded dpm of 0.62, 0.01 % above control
after 2 days of incubation, the cured derivative of strain SB23 yielded dpm of 0.58,0.05 %
above control. The parent Flavobacterium sp. SB23 carrying the 34 Mdal plasmid, pG05,
yielded dpm of 1.5, 0.11 % above control after 2 days of incubation. After 7 days of
incubation, however, both E. coli HB101 and the cured strain of SB23 yielded counts
which were below that of control. The parent Flavobacterium sp. SB23 (pG05) yielded
dpm of 5.3, 0.13 % above control after 7 days of incubation. From these results, it is
concluded that the plasmid-bearing strain showed an increased 14 CO
2
evolution from
14 C-phenanthrene. In one experimental sample, counts for the plasmid-bearing strain
were significantly greater than those of the cured strain. These results suggest that
606
outfall (SO), Ocean City (OC), and clean water (CW) strains.
The results of the experiment designed to transfer the 34 Mdal plasmid back into the
cured derivative strain of SB23 were inconclusive. Plasmid DNA could not be detected in
the transformed cells, even though clearing was observed around the colonies two to four
days after cells undergoing transformation treatment were spread-inoculated onto
phenanthrene-layered agar plates. Lack of detection of the plasmid DNA suggests that
integration of the plasmid into the chromosome may have occurred, as one possible
explanation for this finding.
After 2 days
After 7 days
Strains
DPM*
% of total DPM
DPM
% of Total DPM
above control
above control
Control
223
0.00
718
0.00
E. coli HB101
290.83
0.62 = 0.01
693.93
-0.22 = 0.01
Flavobacterium sp.
SB23 cured
286.33
0.58 = 0.05
581.5
-1.24 = 1.43
Flavobacterium sp.
SB23 (pG05) parent
391.67
1.50 = 0.1
1295.7
5.25 = 0.13
Table 2 : Radiolabeled (
14 C-) Penanthrene Metabolism. * mean DPM (disintegrations per minute) for three
replicate vials.
Flavobacterium sp. SB23 (pG05), known to clear phenanthrene agar, and cured dervivative (non-phenanthrene clearing) strain were tested for their abilities to metabolize (9
-
14 C)-phenanthrene as sole source of carbon and energy (Table 2). While E. coli HB101, a
strain not known to degrade phenanthrene, yielded dpm of 0.62, 0.01 % above control
after 2 days of incubation, the cured derivative of strain SB23 yielded dpm of 0.58,0.05 %
above control. The parent Flavobacterium sp. SB23 carrying the 34 Mdal plasmid, pG05,
yielded dpm of 1.5, 0.11 % above control after 2 days of incubation. After 7 days of
incubation, however, both E. coli HB101 and the cured strain of SB23 yielded counts
which were below that of control. The parent Flavobacterium sp. SB23 (pG05) yielded
dpm of 5.3, 0.13 % above control after 7 days of incubation. From these results, it is
concluded that the plasmid-bearing strain showed an increased 14 CO
2
evolution from
14 C-phenanthrene. In one experimental sample, counts for the plasmid-bearing strain
were significantly greater than those of the cured strain. These results suggest that
606