N-[2-Naphthyl]-glycine hydrazide, a potent inhibitor of DNAdependent RNA polymerase of Mycobacterium tuberculosis H37Rv.

N-[2-Naphthyl]-glycine hydrazide has been shown for the first time as a potent inhibitor of the DNA-dependent RNA polymerase (EC 2.7.7.6) of Mycobacterium tuberculosis H37Rv. At a concentration of 10–9 M, the compound shows maximum inhibition of the enzyme, the inhibition being less at higher concentrations. It is suggested that the novel type of inhibition pattern may be due to hydrophobic interactions occurring between the molecules of the compound at higher concentrations. The finding that there is a shift in the λmax of the compound could also account for this phenomenon. The effect of this compound was also tested on DNA-dependent RNA polymerases from an eukaryotic fungus, Microsporum canis. At a concentration of 10–9 Μ it inhibits RNA polymerase II (32%) but not RNA polymerases I and III.

Preformed messengers in Microsporum canis macroconidia.

Macroconidia of Microsporum canis, when placed in a nutrient medium produce germ tubes within 4–6 h. Precursor incorporation studies showed that protein synthesis occurred prior to RNA synthesis. Sucrose density gradient analysis of wet and dry spore extracts revealed the presence of 16 % and 11 % polysomes respectively. The polysomal content increased to about 50% within 15 min of germination. Synthesis of RNA occurred only after 2 h of germination. Pool equilibration of the radioactive precursors was not limiting to these measurements. Polyadenylated RNA was isolated from macroconidia and was found to comprise 2-2·5 % of the total RNA. The poly(A)+ RNAs were heterodisperse and translatable in a wheat germ cell free translating system. It was concluded that macroconidia of Microsporum canis contain pre-formed mRNA which is translated early in germination.