North M J, Lockwood B C, Bremner A F, Coombs G H
Mol Biochem Parasitol. 1986 Jun;19(3):241-9. doi: 10.1016/0166-6851(86)90006-x.
Trichomonas vaginalis, Tritrichomonas foetus and Trichomitus batrachorum grown in modified Diamond's medium all had high concentrations of putrescine and lower concentrations of spermidine and spermine. Ornithine decarboxylase (ODC; EC 4.1.1.17) was detectable in all three species although at significantly different levels. Trichomonas vaginalis had the highest activity (typically around 1.85 nmol min-1 (mg protein)-1), Trichomitus batrachorum the lowest (0.11 nmol min-1 (mg protein)-1). The Trichomonas vaginalis ODC had an apparent Mr of 230 000 and was severely inhibited by alpha-difluoromethylornithine (DFMO). S-Adenosyl-methionine decarboxylase (EC 4.1.1.50) could not be detected in T. batrachorum but was present in the other two species. Arginine decarboxylase was apparently absent from all three. All three trichomonad species were able to accumulate spermidine and putrescine from the medium. When T. vaginalis was grown in the presence of DFMO (4 mM), which had little effect on parasite growth, ODC activity was reduced by over 99% and the polyamine content was altered; putrescine concentrations were decreased, those of spermidine and spermine remained the same or were raised. DFMO-treated cells accumulated more exogenous putrescine than untreated control cells. The results suggest that the lack of effect of DFMO on T. vaginalis in culture was due to the parasite being able to accumulate polyamines from the growth medium. It appears, therefore, that testing DFMO and similar compounds in axenic trichomonad cultures may well not give a true indication of their effectiveness in vivo where sources of exogenous polyamines may not be available.
在改良的钻石培养基中生长的阴道毛滴虫、胎儿三毛滴虫和蛙三毛滴虫都含有高浓度的腐胺，而亚精胺和精胺的浓度较低。在这三种物种中均能检测到鸟氨酸脱羧酶（ODC；EC 4.1.1.17），尽管其水平存在显著差异。阴道毛滴虫的活性最高（通常约为1.85 nmol min-1（mg蛋白）-1），蛙三毛滴虫的活性最低（0.11 nmol min-1（mg蛋白）-1）。阴道毛滴虫的ODC表观分子量为230000，并且受到α-二氟甲基鸟氨酸（DFMO）的严重抑制。在蛙三毛滴虫中未检测到S-腺苷甲硫氨酸脱羧酶（EC 4.1.1.50），但在其他两个物种中存在。在所有这三种滴虫中显然都不存在精氨酸脱羧酶。所有这三种滴虫物种都能够从培养基中积累亚精胺和腐胺。当阴道毛滴虫在DFMO（4 mM）存在的情况下生长时，DFMO对寄生虫生长影响很小，但ODC活性降低了99%以上，多胺含量发生了变化；腐胺浓度降低，亚精胺和精胺的浓度保持不变或升高。经DFMO处理的细胞比未处理的对照细胞积累了更多的外源性腐胺。结果表明，DFMO对培养的阴道毛滴虫没有影响是由于该寄生虫能够从生长培养基中积累多胺。因此，在无菌滴虫培养物中测试DFMO和类似化合物很可能无法真实反映它们在体内的有效性，因为体内可能无法获得外源性多胺来源。
