6-Thioguanine fromErwinia amylovora

Identification and genetics of 6-thioguanine secreted by Erwinia species and its interference with the growth of other bacteria

“…In plant assays on detached apple flowers, pear slice assays and shoot infection on apple and pear seadlings (MM106 and Kirchensaller Mostbirne) both 6-TG mutants still induced symptom formation. No necrosis was observed when bathing pear slices in a solution of synthetic 6-TG, confirming the findings of Feistner (1986) that it is unlikely to act as phytotoxin. No direct correlation of 6-TG synthesis to pathogenicity was observed.…”

“…In 1986, Feistner and Staub investigated potential phytotoxin production in E. amylovora and therefore analyzed secondary metabolites produced by the pathogen (Feistner and Staub 1986). They demonstrated the production of 6-thioguanine (6-TG) by various E. amylovora isolates, but could exclude a function as phytotoxin for this compound.…”

Proferrioxamine synthesis in Erwinia amylovora in response to precursor or hydroxylysine feeding: metabolic profiling with liquid chromatography-electrospray mass spectrometry

“…Often, the proferrioxamines could serve this purpose; however, in the iron-supplementation studies this was not feasible, because iron at >10 6M suppresses proferrioxamine synthesis (Feistner et al 1993a). In these instances, the extracts were analyzed for 6-thioguanine (6-TG), another metabolic marker for E. amylovora (Feistner & Staub 1986). Since no LC-ESI-MS profiling method for 6-TG is available yet (Feistner 1994b) conventional reversed-phase HPLC analysis (C~s; 2.1 x 220 mm; plus 30 mm precolumn; Applied Biosystems, Foster City, CA) with absorbance detection at 340nm was used.…”

“…The analyses were performed on a Hewlett-Packard (Palo Alto, CA) 1090M workstation, using a linear gradient ofO-50% B over 1-50 min (A = 100% water; B=90% methanol), a flow rate of 0.2mlmin ~, peak controlled acquisition of absorbance spectra (210-400 nm) and an injection volume of 50pl. 6-TG was identified on grounds of its retention time of approximately 13.8 min and its characteristic UV absorbance spectrum (Feistner & Staub 1986). …”

Caracterización fenotípica y genotípica de aislados españoles de Erwinia amylovora.

“…En la búsqueda de moléculas tóxicas producidas por E. amylovora, potencialmente responsables de la patogenicidad, se han aislado dos metabolitos secundarios. Uno de ellos es la 6-tioguanina (Feistner y Staub, 1986), que finalmente no mostró efectos tóxicos en células de peral en cultivo. El otro es la 2,5-dihidrofenilalanina (DHP) (Feistner, 1988), considerada inicialmente como una necrotoxina, para la cual se propuso un papel importante en la patogenicidad, aunque la inconsistencia en la producción de esta molécula no apoya dicha función.…”