Cytokinin-like activity of N,N'-diphenylureas. N,N'-bis-(2,3-methylenedioxyphenyl)urea and N,N'-bis-(3,4-methylenedioxyphenyl)urea enhance adventitious root formation in apple rootstock M26 (Malus pumila Mill.).

Vegetative propagation of cuttings is a widespread method to multiplicate plants. Adventitious root formation is a key step in vegetative propagation and considerable progress has recently been made in understanding root formation. But, in spite of the efforts made, no new rooting treatments have been developed. Here, we report for the first time, that N,N'-bis-(2,3-methylenedioxyphenyl)urea and N,N'-bis-(3,4-methylenedioxyphenyl)urea enhance adventitious root formation in microcuttings of Malus pumila Mill. rootstock M26. Roots emerge without auxin supplementation in the darkness, transfer in hormone free medium, or callus formation. With the use of different bioassays, we also demonstrate that these two diphenylurea derivatives do not show cytokinin- or auxin-like activity.

Biological studies on 1,2-benzisothiazole derivatives VI Antimicrobial activity of 1,2-benzisothiazole and 1,2-benzisothiazolin-3-one derivatives and of some corresponding 1,2-benzisoxazoles.

Numerous 1,2-benzisothiazole and 1,2-benzisothiazolin-3-one derivatives, variously substituted in the different positions of the molecule, were tested for their in vitro antimicrobial activity. Some corresponding 1,2-benzisoxazoles and 1,2-benzisoxazolin-3-ones were also considered. Several compounds possess a potent and broad antibacterial and antifungal activity, particularly against Gram positive microorganisms, yeasts and dermatophytes. 1,2-Benzisothiazolin-3-ones were found to be the most active substances. On the contrary, the benzisoxazoles and the benzisoxazolin-3-ones considered were devoid of activity. The results obtained are discussed on the basis of structure-activity relationships.

Biological studies on 1,2-benzisothiazole derivatives. IV. Relationships between chemical structure and genotoxicity.

This paper describes in vitro evaluation by Bacillus subtilis rec-assay and Salmonella-microsome assay of the genotoxic properties of some 1,2-benzisothiazole and 1,2-benzisothiazolin-3-one derivatives, containing groups (aromatic nitro, aromatic amino, epoxide groups) often associated with mutagenic properties and defined as "alerting groups". Compounds 2, 3, 4, 7, 8, 9, 11, 14, 16, 20, 21 and 22 exhibited DNA-damaging activity. The Salmonella-microsome assay confirmed the genotoxic activity of these compounds, which was also demonstrated for compounds 5, 6, 10, 12, 13, 15, 17, 18, 19, 25 and 27. Relationships between chemical structure and genotoxic activity showed that all the 1,2-benzisothiazole derivatives containing an alerting group were active. On the contrary, among 1,2-benzisothiazolin-3-one derivatives, compounds 24 and 26 were non-mutagenic, although an alerting group was present in the molecule.

[Imidazopyrimidines with cytokinin activity]. / Imidazopirimidine ad attivita citochininica.

Some imidazopyrimidines structurally analogous to the corresponding natural kinetics (adenine, benzyladenine, kinetic) were prepared and tested for cytokinin-like activity. Among the compounds tested for ability to retard degradation of the photosynthetic system, the 7-chloroderivatives (II-III) showed activity comparable with that of natural kinetic and confirm the chlorine function as a potentiator of biological activity.