Escherichia coli KK313, which was deficient in spermidine transport, was isolated by treatment of E. coli MA261 with N-methyl-N'-nitro-N-nitrosoguanidine. E. coli NH1596, which was deficient in spermidine transport and has a 90% decreased putrescine transport activity, was obtained by a second treatment of E. coli KK313 with the same mutagen. Genes for polyamine transport systems were isolated ...

In order to investigate the seasonal changes and the possible role of the free polyamines in the leaves and stems on the alternate bearing habit of the ‘Kinnow’ mandarin (Citrus reticulata Blanco) trees, a comparative study was conducted to analyze the levels of free polyamines  (putrescine, spermidine and spermine) in the leaves and stems tissues of “on” and &ldquo...

The effect of methylglyoxal bis(guanylhydrazone), a substance known to inhibit putrescine-dependent S-adenosyl-l-methionine decarboxylase, on polyamine metabolism in liver and kidney was investigated. Almost complete inhibition of the incorporation of putrescine into spermidine was obtained up to 8h after administration of 80mg of methylglyoxal bis(guanylhydrazone)/kg body wt. by intraperitonea...

Polyamine uptake and metabolism were studied in cultures of normal and Rous sarcoma virus-transformed chick embryo fibroblasts. The uptake of radioactive putrescine and spermidine by the transformed cells was faster than that of the normal controls. The amount of radioactive putrescine and polyamines taken up by the transformed cells also exceeded that observed with normal fibroblasts. The intr...

How polyamines such as spermidine cooperate with histone to condense and de-condense DNA during transcription has not been clarified. In this work, using the complex of DNA and poly(L-lysine) (PLL) at +/- ratio of 0.5 as a model of nucleosome, we monitored the de-condensation of DNA in the presence of spermidine. As revealed by the results from atomic force microscopy and time-resolved laser li...

The biosynthesis of the spermidine and guanidino groups has been studied with carbon-14 and carbon-13 labeled intermediates. Arginine, citrulline and ornithine are incorporated in good efficiency. The guanidino group of arginine and the ureido group of citrulline both label the guanidino group on the hexose sugar. None of the ureido groups in the antibiotic was enriched. It is likely that citru...

Spermidine is a naturally occurring polyamine which regulate growth processes in living beings. Using solid phase synthetic strategy spermidine was synthesised. The only purification process involved throughout the synthesis is filtration and washing with suitable solvents. Spermidine was first synthesised over polystyrene support and then cleaved from matrix photolytically. The yield and purit...

Polyamine depletion by pretreatment with alpha-difluoromethylornithine (DFMO), a specific and irreversible inhibitor of ornithine decarboxylase, potentiates the cytotoxicity of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) in L1210 leukemia cells grown in a modified soft agar system. The dose enhancement ratio was 1.97 at a control colony formation level of 5%. The basis for this enhancement was ...

We have reported that a single injection of 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25(OH)2D3), the active form of vitamin D3, into vitamin D-deficient chicks produces a marked increase in the formation of duodenal putrescine by two pathways, one from ornithine and one from spermidine (Shinki, T., Takahashi, N., Kadofuku, T., Sato, T., and Suda, T. (1985) J. Biol. Chem. 260, 2185-2190). In this...