Purine auxotrophs of various Rhizobium species are symbiotically defective, usually unable to initiate or complete the infection process. Earlier studies demonstrated that, in the Rhizobium etli-bean symbiosis, infection by purine auxotrophs is partially restored by supplementation of the plant medium with 5-amino-imidazole-4-carboxamide (AICA) riboside, the unphosphorylated form of the purine ...

The pathways of purine biosynthesis and degradation have been elucidated during the last 30 years; the regulation of the mechanisms involved is not yet fully understood, particularly with respect to quantitative aspects. Research into inborn errors of purine metabolism has provided valuable insights into purine synthesis and salvage pathways. Nutrition experiments using purine-free formula diet...

Summary Ascospores generated during sexual reproduction are the primary inoculum for wheat scab fungus Fusarium graminearum . Purine metabolism is known to play important roles in fungal pathogens but its lifecycle stage‐specific regulation unclear. By characterizing genes involved purine de novo and salvage biosynthesis pathways, we showed that syntheses of inosine, adenosine guanosine monopho...

7-Hydroxyguanine, an antitumor purine-analog, reacted with ribose (or deoxyribose)-1-phosphate in the presence of purine nucleoside phosphorylase. We prepared 7-hydroxyguanine riboside and deoxyriboside using purine nucleoside phosphorylase from bovine spleen. Each nucleoside exhibits antitumor activity against mouse leukemia L1210 cells. The therapeutic effect of 7-hydroxyguanine deoxyriboside...

Clostridium feseri (chuavoei), ATCO-10092, grows well in a semi-synthetic basal medium devoid of purine bases and folic acid. Growth inhibition of this organism in such a medium by carcinostatic purine analogs is pronounced, and by pyrimidine analogs marked. Purines in the medium block the growth inhibition of Clostridium feseri by purine analogs. Greater agreement occurs between the growth inh...

A clone (AE1) of cells resistant to adenosine cytotoxicity was isolated from a mutagenized population of mouse T-lymphoma (S49) cells. These adenosine-resistant cells cannot transport adenosine or any other purine or pyrimidine nucleoside tested, but their transport of purine bases is intact. The AE1 cells also have an impaired ability to salvage thymidine. Kinetic analyses of the uptake of pur...

The purine bases hypoxanthine, xanthine, guanine, and purine markedly inhibit epinephrine-induced lipolysis in rat adipose tissue, an action previously ascribed only to nucleosides, nucleotides, and nucleic acids. The inhibition by purines and purine conjugates is associated with increased destruction of epinephrine. Allopurinol, an inhibitor of xanthine oxidase, prevents the degradation of epi...

Rates of purine salvage of adenine and hypoxanthine into the adenine nucleotide (AdN) pool of the different skeletal muscle phenotype sections of the rat were measured using an isolated perfused hindlimb preparation. Tissue adenine and hypoxanthine concentrations and specific activities were controlled over a broad range of purine concentrations, ranging from 3 to 100 times normal, by employing...

The megaloblastic anemia of cobalamin deficiency appears secondary to decreased methionine synthetase activity. Decreased activity of this enzyme should cause 5-methyltetrahydrofolate to accumulate intracellularly, and consequently, decrease purine and DNA synthesis; this is the basis of the "methylfolate trap" hypothesis of cobalamin deficiency. However, only some of the clinical and biochemic...