[FIGURE 1 OMITTED] Table 1 Number or revertants
colonies were counted, and the toxic effect was determined by viewing the background lawn under a stereo microscope.
Individual plate counts were recorded and the mean number of revertant
colonies per plate as well as the standard deviation was calculated.
TABLE 2: Number of Salmonella typhimurium TA97, TA198, TA100, TA1535, and TA102 revertant
colonies per plate in the presence of the PBN derivate following the preincubation procedure of the Salmonella/microsome assay in the absence (-) and in the presence (+) of exogenous metabolizing system from rat liver S9-mix.
Until alternative vaccines become commercially available, control of AHS will remain reliant on the use of AHSV-LAV coupled with the adoption of strategies to minimize the likelihood of natural dissemination of revertant
and reassortant vaccine-derived viruses.
We defined a positive mutagenic response as a reproducible, dose-related response with a 2-fold or greater increase in revertants
(rev) per plate relative to the DMSO control.
(1995) Expression of ril, a novel LIM domain gene, is down-regulated in Hras-transformed cells and restored in phenotypic revertants
. Oncogene 10(1): 61-68.
Some "escaped" and persistent cultivated tetraploids in the Andes ("Araq" potatoes) and some putative "wild" species may be revertants
from cultivation (Spooner et al.
There were no revertants
exceeding three times the background average either with or without the metabolic activation system.
These results were confirmed by Kwon--Chung et al (1985) and they also showed that revertants
with restored proteolytic activity also regained their virulence.
SR: spontaneous revertants
. Positive controls: TA98: picrolonic acid (PA) (50 [micro]g/Petri dish) without S9, 475.0 [+ or -] 33.42, [His.sup.+] revertants
; (2AA) 2-aminoanthracene (10 [micro]g/Petri dish) with S9, 2354.83 [+ or -] 222.49; TA100: methyl-N'-nitro-N-nitrosoguanidine (MNNG), (10 [micro]g/Petri dish) without S9, 5,881.17 [+ or -] 861.49, (CF) cyclophosphamide (500 [micro]g/Petri dish) with S9, 530.0 [+ or -] 60.97; TA102: mitomycin C (2 ng/Petri dish) without, 3,401.67 [+ or -] 703.37, 2AA (10 [micro]g/Petri dish) 1,264.83 [+ or -] 77.38.
Furthermore, on King's B agar plates where the Wrinkly Spreader is genetically unstable and rapidly generates Smooth-like revertants
(phenotypically similar to the biofilm cheaters recovered from static microcosms), the Wrinkly Spreader has an even lower fitness (W = 0.15) 62].