Matta M A, Alviano C S, Angluster J, De Souza W, Silva-Filho F C, Esteves M J
Instituto de Microbiologia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Brazil.
Cell Biophys. 1992 Feb;20(1):69-79. doi: 10.1007/BF02782655.
Surface charge of wild-type Crithidia fasciculata and three drug-resistant mutants (TR3, TFRR1, and FUR11) was studied by direct zeta-potential determination and ultrastructural cytochemistry. Surface tension was also investigated by measurements of the advancing contact angle formed by the protozoa monolayers with drops of liquids of different polarities. The individual zeta potential varies markedly among the C. fasciculata cells. The wild and FUR11 mutant strains displayed lower negative surface charge (-12.5 and -9.5 mV, respectively) as compared with the TR3 (-14.8 mV) and TFRR1 (-14.7 mV) mutant strains. Binding of cationized ferritin (CF) was observed at the cell surface of wild and mutant strains of C. fasciculata. Neuraminidase treatment reduced the negative surface charge in the TFRR1 and TR3 mutants in about 37 and 29%, respectively, whereas no significant change was observed with the wild and FUR11 mutant strains. These findings suggest that sialic acid residues are the major anionogenic groups on the surface of C. fasciculata. The density of sialic acid residues per cell in wild and mutant strains of C. fasciculata falls in a range of 1.4 x 10(4) to 3.6 x 10(4). Marked differences of hydrophobicity were also observed. For example, the TFRR1, FUR11, and TR3 drug-resistant mutant strains showed higher contact angle values (55.4, 54.2, and 49.3, respectively) than the wild-type (35.6), as assessed by alpha-bromonaphtalene.
通过直接测定ζ电位和超微结构细胞化学方法，研究了野生型克氏锥虫及三种耐药突变体（TR3、TFRR1和FUR11）的表面电荷。还通过测量原生动物单层与不同极性液体滴形成的前进接触角来研究表面张力。克氏锥虫细胞的个体ζ电位差异显著。与TR3（-14.8 mV）和TFRR1（-14.7 mV）突变株相比，野生型和FUR11突变株的表面负电荷较低（分别为-12.5和-9.5 mV）。在克氏锥虫野生型和突变株的细胞表面观察到阳离子铁蛋白（CF）的结合。神经氨酸酶处理使TFRR1和TR3突变体的负表面电荷分别降低了约37%和29%，而野生型和FUR11突变株未观察到显著变化。这些发现表明，唾液酸残基是克氏锥虫表面主要的阴离子基团。克氏锥虫野生型和突变株每个细胞的唾液酸残基密度在1.4×10⁴至3.6×10⁴范围内。还观察到明显的疏水性差异。例如，通过α-溴萘评估，TFRR1、FUR11和TR3耐药突变株的接触角值（分别为55.4、54.2和49.3）高于野生型（35.6）。
