Mucoid variant mutated from Mutabile-type Var. (Murase) or mucoid RT mutated from the mucoid variant are inhibited in their growth upon the plating on to the 0.5-1.0 % Na
2SO
3 agar. However, no inhibition is observed when the non-mucoid one such as Mutabile-type Var., and its so-called back mutant, the RT. are plated. Also, same tendency is seen in case of mucoid var. mutated from the original type of Salmonella or Escherichia and the resistant strains of mucoid RT of them.
Inhibition phenomenon is always observed when the organisms are cultured on the Na
2SO
3 agar plate or kept in the Na
2SO
3 saline or broth in the incubator at 37°C but not in the refrigerator.
If the paper disc method is employed and the plate is kept in the refrigerator over night before incubation at 37°C, no inhibition zone could be proved because of too diluted diffusion of Na
2SO
3.
The activity of Na
2SO
3 is thought to be dependent to the weak bactericidal power of the compound. Its activity is resistant to the autoclaving (15 lb 20') or Koch's sterilization (100°C 30' 3x) .
The Na
2SO
3 agar plate may be active over 3 weeks when it is preserved anaerobically. Na
2SO
3 obtained from the newly opened bottle is more active than that of the old one.
The Na
2SO
3 loose its activity in accordance with the loss of fuchsinreducing power.
The antibacterial activities are examined on Na
2SO
3 and its derivates. No activity was found on Na
2SO
4. Na
2S
2O
3 showed rather milder activity than that of Na
2SO
3 and NaHSO
3 was the most active both to mucoid varr. and non-mucoid vary. No selective action was observed
PH of the Na
2SO
3 and its derivates has no effect against the activity specifically. But, when the PH of NaHSO
3 is adjusted to that of Na
2SO
3, the activity is rather lowered and permits the growth of some mucoid variant colonies, even no growth is allowed in the former concentration. Therefore it is believed that the activity of Na
2SO
3 against our two kinds of strains of mucoid varr. means the weak bactericidal and bacteriostatic power in relation to the reducing power of the compound. To clarify the selective action of Na
2SO
3 on the mucoid varr. further investigations should be performed.
View full abstract