Article Figures & Data
Figures
- FIG. 1.
Recombination frequency in ME as a function of the distance between markers. A. Marker separations of 0 to 1,154 bp. Frequencies are numbers of Pyr+ recombinants per cell plated, representing median values from four to seven independent determinations (the horizontal line marks the average of all medians); error bars indicate standard deviations. B. Effect of DNA damage. Washed cell suspensions were divided in half, and one half received 50 J/m2 of UV-C radiation before the mating. Mean numbers of recombinants per CFU and standard deviations (error bars) were normalized to the average of all values for each treatment. Solid symbols, untreated; open symbols, UV irradiated.
- FIG. 2.
Comparison of S. acidocaldarius ME to other systems. A. Logarithmic plot. Straight lines approximate linear regressions of the surrounding points, with the following slopes: E. coli plasmid recombining with bacteriophage λ (25), 1.0; bacteriophage T4 mutants (26), 2.0; plasmid integration into L. sake chromosome (15), 2.2; linearDNA integrating into Chinese hamster ovary cell APRT gene (23), 3.5; S. acidocaldarius conjugational crosses (data of Fig. 1A), 0.5. B. Arithmetic plot. To facilitate comparison, the recombinant frequencies for each system were normalized to the average value over the interval shown. Data are corresponding subsets of those in Fig. 1A. Lines approximate linear extrapolation of higher frequencies to zero recombination.
- FIG. 3.
Tests for genetic linkage. Three-factor crosses used to evaluate genetic linkage by ME. The ×'s symbolize point mutations, whereas the open brackets represent the 18-bp deletion in strain MR31. Predicted frequencies of Pyr+ recombinants are based on corresponding distances in E. coli Hfr crosses (16).
Tables
- TABLE 1.
Deletion mutants as recipients in ME
γ-Ray dose (kilorads) Avg survival Parental strain irradiateda Relative efficiency of deletion mutant Parental strain irradiateda Relative efficiency of deletion mutant JDS10 MR311 Neither JDS21 MR103 Neither 100 6.8 × 10−4 0.77 ± 0.25b (8) 4.33 ± 2.46 (10) 3.94 ± 0.66 (2) 0.18 <0.007 (8) 9.80 ± 4.22 (6) 2.96 ± 0.67 (4) <0.001 150 5.6 × 10−5 1.34 ± 0.97 (8) 4.51 ± 1.31 (8) 2.99 ± 1.05 (8) 0.30 0.007 (8) 12.2 ± 2.6 (8) 0.71 ± 0.45 (4) 0.001 200 1.6 × 10−4 0.81 ± 0.41 (8) 2.58 ± 2.64 (8) 10.1 ± 3.2 (4) 0.31 0.22 ± 0.22 (8) 70.1 ± 64.0 (8) 4.64 ± 1.94 (4) 0.003
