Highly selective assay of proteins in dilute solutions.

A very simple, highly selective assay of proteins has been developed. Solutions of 6 M hydrochloric acid containing 0-20 mug ml(-1) protein are subjected to acid hydrolysis, in the presence of air, during their evaporation to dryness on a steam bath. Then, the resulted amino acids are determined with a 2,2-dihydroxy-1,3-indanedione reagent.

[Antimicrobial activity of new 4,4'-bipyridine derivatives: and in vitro study].

The antimicrobial and antifungal activity of some 4,4'-bipyridine derivatives were studied. The diffusimetric gelose surface diffusion method with stainless steel cylinders was used to study bacteria and Sabouraud fields for Candida albicans. Comparative analysis of the results led to the following conclusions.

Cyanide reaction with ninhydrin: elucidation of reaction and interference mechanisms.

A new sensitive spectrophotometric method has recently been developed for the trace determination of cyanide with ninhydrin. Cyanide ion was supposed to act as a specific base catalyst. Nevertheless, this paper demonstrates that the reported assay is based on a novel reaction of cyanide with 2,2-dihydroxy-1,3-indanedione, which affords purple or blue colored salts of 2-cyano-1,2,3-trihydroxy-2H indene.

[In vitro antimicrobial activity of new 1,10-phenantroline derivatives].

The antimicrobial and antifungical activities of some 1,10-phenanthroline derivatives are described. The test was performed using the diffusimetric method with stainless steel cylinders based on diffusion of the substances on the gelose surface for bacteria and Sabouraud field for Candida Albicans yeast. The comparative analysis of the obtained data leads to the following conclusions concerning the relation between structure and activity