Putrescine utilizing cells

Experiments utilizing D,L-a-difluoromethylornithine (DFMO), an irreversible inhibitor of ornithine decatboxylase, to determine its effect on mitogen- or al-loantigen-induced lymphocyte proliferation and CTL induction have certain similarities to the inhibition seen in N=0-induced inhibition of lymphocyte function. Stimulation of both mouse and human T cells in the presence of DFMO results in partial inhibition of proliferation which can be reversed by addition of the polyamines putrescine, spermidine, and spermine (Bowlin et al., 1987 McCarthy et al., 1990). lL-2 levels in these lymphocyte cultute supernatants as well... 

The production of berberine in cell suspension cultures of T. minus var. hypoleucum was greatly enhanced via the administration of spermidine. However, the utilization of other polyamines including cadaverine, putrescine, and spermine were not effective. Experimental results indicate that spermidine induces an increase in the production of ethylene, the latter of which is definitively associated with the biosynthesis of berberine [161]. 

Most pyrrolizidine alkaloids are esters of basic alcohols known as necine bases. The most frequently studied pyrrolizidine alkaloids are formed from the polyamines, putrescine and spermidine, and possess one of three common necine bases retronecine, heliotridine, and otonecine. Putrescine is utilized exclusively as a substrate in secondary metabolism, whereas spermidine is a universal cell-growth factor involved in many physiological processes in eukaryotes. Spermidine biosynthesis begins with the decarboxylation of SAM by SAM decarboxylase 165). The aminopropyl group is then transferred from decarboxylated SAM to putrescine by spermidine synthase to form spermidine (Scheme 5). Putrescine can be produced from ornithine by ODC. However, putrescine is derived from the arginine-agmatine pathway in pyrrolizidine alkaloid-producing plants due to the absence of ODC activity 166). 

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