Markos A, Blahůsková A, Kalous M, Bysková E, Byska K, Nohýnková E
Department of Physiology and Developmental Biology, Faculty of Sciences, Charles University, Prague, Czechoslovakia.
Folia Parasitol (Praha). 1989;36(3):225-38.
Bloodforms of Trypanosoma brucei brucei STIB 247 taken from rats and containing more than 80 per cent short stumpy forms, differentiated in vitro to procyclic forms in medium SDM 79 (Brun and Schönenberger 1979), enriched with 3 mmol.dm-3 cis-aconitate. Cell division was abolished by the addition of hydroxyurea (200 micrograms.ml-1) or arabinosyl adenine (20 micrograms.ml-1 to the cultivation medium, or by the omission of serum from the medium. The ultrastructure of exponentially growing controls was rearranged within 24 h. The endogenous respiration and the respiration stimulated by proline, succinate, and 2-oxoglutarate were detectable within 12 h; after 48 h the respiration rates were comparable to those found in the established procyclic forms. After 12 h the respiration was inhibited by 200 mumol.dm-3 KCN, and by 20 mumol.dm-3 antimycin to the extent found in procyclic forms. Hydroxyurea did not significantly affect respiration. Activities of procyclic-stage enzyme markers malate dehydrogenase, threonine dehydrogenase, succinate: cytochrome c reductase, and NADH: cytochrome c reductase rose within 48 h of differentiation to values which were close to those found in established procyclic forms. The activity of glutamate dehydrogenase (NAD-specific), however, was only 1/3 of that in the procyclics, and no citrate synthase was detected in differentiating culture. Glycosomal malate dehydrogenase was detected after 6 h. In the presence of hydroxyurea or arabinosyl adenine, or in the absence of serum, respiration rates, marker enzyme activities, and glycosomal malate dehydrogenase developed to the extent comparable to the untreated controls. The results suggest that it is possible to separate the process of differentiation from cell proliferation. Cell division is not a necessary prerequisite of differentiation.
从大鼠体内获取的布氏布氏锥虫STIB 247的血液形态，其中短粗型形态占比超过80%，在添加了3 mmol·dm⁻³顺乌头酸的SDM 79培养基（Brun和Schönenberger，1979）中体外分化为前循环型。通过向培养基中添加羟基脲（200微克·毫升⁻¹）或阿拉伯糖基腺嘌呤（20微克·毫升⁻¹），或从培养基中去除血清，可抑制细胞分裂。指数生长的对照细胞的超微结构在24小时内发生重排。内源性呼吸以及由脯氨酸、琥珀酸和2-氧代戊二酸刺激的呼吸在12小时内即可检测到；48小时后，呼吸速率与已建立的前循环型中的呼吸速率相当。12小时后，呼吸受到200微摩尔·dm⁻³ KCN和20微摩尔·dm⁻³抗霉素的抑制，抑制程度与前循环型中相同。羟基脲对呼吸没有显著影响。前循环期酶标志物苹果酸脱氢酶、苏氨酸脱氢酶、琥珀酸：细胞色素c还原酶和NADH：细胞色素c还原酶的活性在分化48小时内升至接近已建立的前循环型中的值。然而，谷氨酸脱氢酶（NAD特异性）的活性仅为前循环型中的1/3，并且在分化培养物中未检测到柠檬酸合酶。6小时后检测到糖体苹果酸脱氢酶。在存在羟基脲或阿拉伯糖基腺嘌呤的情况下，或在无血清的情况下，呼吸速率、标志物酶活性和糖体苹果酸脱氢酶的发展程度与未处理的对照相当。结果表明，有可能将分化过程与细胞增殖分开。细胞分裂不是分化的必要前提条件。
