A simple thin-layer chromatographic system for the separation of the iso,prenologues of vitamin K, is described. This system employs hexadecane-impregnated Kieselguhr thin-layer plates and an acetone-water solvent system. Using ~c-[r-W]naphthol or Z-[l‘X]methyl-x,4-naphthoquinone and DL-[5-3H]mevalonate, the separation of the isoprenologues was confirmed. Each isoprenologue was recovered quanti...

A new extraction procedure is applied here to radioimmunoassay of serum estradiol. Small columns packed with porous, grainy kieselguhr are loaded with the samples. The kieselguhr material acts as support for the water phase, from which the lipophilic compound estradiol is eluted with diethyl ether. With use of a specially constructed rack, several columns can be handled simultaneously, which ma...

OBJECTIVE To evaluate the insecticidal effect of diatomaceous earth (DE) against adults and nymphs of Blattella germanica. METHODS This cross sectional study has been done on the laboratory strain of German cockroaches. Two stages, nymph and adult, were exposed to six dose rates of the DE, 2.5, 5, 10, 15, 20 and 25 g/m(2), at 24, 48 and 72 h exposure period. Mortality (number of dead cockroac...

The distribution of pyrimidine oligodeoxynucleotide clusters in L and H strands of Bacillus subtilis DNA separated by methylated albumin-Kieselguhr has been determined. Preparations of native and single-stranded DNA were degraded with diphenylamine in formic acid, and the released isostichs with the general formula of Py(n)P(n+1) were separated on DEAE-cellulose by chain length. Eleven isostich...

Red light, which produces the physiologically active form of phytochrome (Pfr), inhibited epicotyl elongation in intact dark-grown Alaska pea seedlings. This red light response was detectable 3 hours after the light treatment and became pronounced after 5 hours. The growth inhibition was completely reversed by far red light applied immediately after the red or by pretreatment of the seedlings w...