Table 3.

Relationship between amplification level for theclc element and capability to metabolize MCB

Derivative strainGrowth on MCBaMean copy no. of theclc element on XbaI restriction fragments ofb:
48 kb75 kb100 kb
RR221110
RR2231110
RR2232110
RR2233++115
RR2234+111
RR2235+111
RR2236+111
RR2237+111
RR2238++113
RR2239110
RR2240110
RR22 MCBc +++116
  • a Relative capabilities to grow on MCB were tested by spotting 10 μl of overnight-grown LB medium cultures (except for strain RR22) on a mineral agar plate incubated in the presence of MCB vapor. −, no growth; +, moderate growth; ++, good growth; +++, excellent growth. It was not feasible to determine actual growth rates on MCB due to the unstable genotypes of these strains.

  • b The relative levels of hybridization of theXbaI restriction fragments to the clc-gene probe were determined densitometrically. This determination provided an estimation of how many copies of the clc element were included in the 100-kb XbaI band.

  • c Strain RR22 cultivated on MCB.