LeFurgey A, Ingram P, Blum J J
Department of Cell Biology, Duke University Medical Center, Durham, NC.
Mol Biochem Parasitol. 1990 Apr;40(1):77-86. doi: 10.1016/0166-6851(90)90081-v.
Leishmania major promastigotes contain electron-dense vacuoles. The elemental composition of these vacuoles and of the cytoplasm was measured by electron probe X-ray microanalysis, using rapid cryopreservation techniques to prevent alterations in composition due to diffusion. The electron-dense vacuoles are rich in P, presumably present as polyphosphate (poly P). Mg is present at about 9 times its cytoplasmic level. There is sufficient Mg to largely neutralize most of the negative charge of the Poly P. The electron-dense vacuoles also contain appreciable amounts of Ca and Zn, which are not detectable in the cytoplasm, as well as Na, K, and Cl, the latter two at concentrations below that of the cytoplasm. These results suggest that the vacuolar membranes have at least one cation transport system. Incubation of the promastigotes for 1 h in the absence of phosphate in the presence or absence of glucose did not cause significant changes in the vacuolar contents of P, Mg, or Zn, but changes in K and Cl content were observed in both the electron-dense vacuoles and in the cytoplasm.
硕大利什曼原虫前鞭毛体含有电子致密液泡。利用快速冷冻保存技术防止因扩散导致成分改变，通过电子探针X射线微量分析测定了这些液泡和细胞质的元素组成。电子致密液泡富含磷，推测以多聚磷酸盐（多聚P）形式存在。镁的含量约为其细胞质水平的9倍。有足够的镁来大致中和多聚P的大部分负电荷。电子致密液泡还含有大量在细胞质中无法检测到的钙和锌，以及钠、钾和氯，后两者的浓度低于细胞质中的浓度。这些结果表明液泡膜至少有一个阳离子转运系统。在有或没有葡萄糖存在的情况下，将前鞭毛体在无磷酸盐的条件下孵育1小时，不会导致液泡中磷、镁或锌含量发生显著变化，但在电子致密液泡和细胞质中均观察到钾和氯含量的变化。
