Villasuso Ana L, Romero Patricio, Woelke Mariela, Moyano Patricia, Machado Estela, de Lema Mirta García
Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, CPX5804BYA, Río Cuarto, Córdoba, Argentina.
Lipids. 2010 Mar;45(3):275-83. doi: 10.1007/s11745-010-3387-2. Epub 2010 Feb 4.
Fetal bovine serum (FBS) is an important factor in the culture of Trypanosoma cruzi, since this parasite obtains and metabolizes fatty acids (FAs) from the culture medium, and changes in FBS concentration reduce the degree of unsaturation of FAs in phosphoinositides. When T. cruzi epimastigotes were cultured with 5% instead of 10% FBS, and stearic acid was used as the substrate, (9) desaturase activity decreased by 50%. Apparent K (m) and V (m) values for stearic acid, determined from Lineaweaver-Burk plots, were 2 microM and 219 pmol/min/mg of protein, respectively. In studies of the requirement for reduced pyridine nucleotide, (9) desaturase activity reached a maximum with 8 microM NADH and then remained constant; the apparent K (m) and V (m) were 4.3 microM and 46.8 pmol/min/mg of protein, respectively. The effect of FBS was observed only for (9) desaturase activity; (12) desaturase activity was not affected. The results suggest that decreased FBS in culture medium is a signal that modulates (9) desaturase activity in T. cruzi epimastigotes.
胎牛血清（FBS）是克氏锥虫培养中的一个重要因素，因为这种寄生虫从培养基中获取并代谢脂肪酸（FAs），并且FBS浓度的变化会降低磷酸肌醇中脂肪酸的不饱和度。当克氏锥虫前鞭毛体在5%而非10%的FBS中培养，且以硬脂酸作为底物时，（9）去饱和酶活性降低了50%。根据Lineaweaver-Burk图确定的硬脂酸的表观K（m）和V（m）值分别为2 microM和219 pmol/分钟/毫克蛋白质。在对还原型吡啶核苷酸需求的研究中，（9）去饱和酶活性在8 microM NADH时达到最大值，然后保持恒定；表观K（m）和V（m）分别为4.3 microM和46.8 pmol/分钟/毫克蛋白质。仅在（9）去饱和酶活性方面观察到了FBS的影响；（12）去饱和酶活性未受影响。结果表明，培养基中FBS的减少是一种调节克氏锥虫前鞭毛体（9）去饱和酶活性的信号。
