Growth inhibitory effect of sodium azide in chemosensitivity assays

In vitro chemosensitivity assays based on colony counting are plagued by persistent incidence of false-negative results. To avoid serious predictive errors, some investigators have utilized positive controls (known toxic compounds) as a quality control measure. Sodium azide (NaN3) at 6 mg/ml failed to inhibit colony formation in 17/35 (49%) assays; while in the thymidine incorporation assay, sodium azide was effective in inhibiting 124/131 (95%) specimens. Positive control substances for use in chemosensitivity assays must be carefully selected to insure accurate results.     

Novel effect of azide on sodium channel of Xenopus oocytes

Bath application of a few mM of sodium azide to a voltage clamped oocyte activated a voltage dependent Na+ current. Characteristics of the azide-induced current were the same as those of already described Na+ current induced by prolonged depolarization. The Na+ current induced either by azide or depolarization was suppressed by the application of Ca2+ channel blockers (Diltiazem and La3+). Azide is known to affect some metabolic processes (ATP and cGMP production etc.), but the present effect could not be attributed to metabolic actions.     

The effect of growth regulators on sodium azide induced genetic damage in barley

The influence of growth regulators (GA and IAA) on the genetic effects of sodium azide was studied. Treatments with growth regulators were administered either prior to or after the mutagen. Post-treatments were found to be more effective against mutagen-induced plant growth injury and gave a slightly higher frequency of mutations. M₁ spike sterility however showed a rise following treatments with growth regulators.     

The effect of sodium azide on the thermotolerance of the yeast Saccharomyces cerevisiae and Candida albicans

The addition of sodium azide (a mitochondrial inhibitor) at a concentration of 0.15 mM to glucosegrown Saccharomyces cerevisiae or Candida albicans cells before exposing them to heat shock increased cell survival. At higher concentrations of azide, its protective effect on glucose-grown cells decreased. Furthermore, azide, even at low concentrations, diminished the thermotolerance of galactose-grown yeast cells. It is suggested that azide exerts a protective effect on the thermotolerance of yeast cells when their energy requirements are met by the fermentation of glucose. However, when cells obtain energy through respiratory metabolism, the azide inhibition of mitochondria enhances damage inflicted on the cells by heat shock.     

The susceptibility ofSpirillum minus andBorrelia duttoni to streptomycin and penicillin

Summary An investigation into the effect of streptomycin and penicillin onSpirillum minus infections in mice, guinea pigs and hamsters, showed that streptomycin effectively controlledSpirillum infections in guinea pigs, but that this antibiotic was not always efficacious in mice and hamsters. Penicillin, when given in rather high dosages, seemed to be more reliable. Both antibiotics were absolutely inadequate for the control ofBorrelia duttoni infections in mice.     

The very low mutagenic activity of sodium azide inArabidopsis thaliana

Sodium azide, reported to be a strong mutagen in barley, revealed a very weak mutagenic activity inArabidopsis.