Jana T K, Srivastava A K, Csery K, Arora D K
Laboratory of Applied Mycology, Centre of Advanced Study in Botany, Banaras Hindu University, India.
Can J Microbiol. 2000 Jan;46(1):28-37.
The relative cell surface hydrophobicity (CSH) of 18 soil isolates of Pseudomonas fluorescens, determined by phase exclusion, hydrophobic interaction chromatography (HIC), electrostatic interaction chromatography (ESIC), and contact angle, revealed large degrees of variability. Variation in the adhesion efficiency to Macrophomina phaseolina of the hyphae/sclerotia of these isolates was also examined. Two such isolates with maximum (32.8%; isolate 12-94) and minimum (12%; isolate 30-94) CSH were selected for further study. Early- to mid-log exponential cells of these isolates were more hydrophobic than those in stationary phase, and the CSH of these isolates was also influenced by fluctuations in temperatures and pH. Isolate 12-94 exhibited high CSH (32.3%) at 30 degrees C, compared to lower values (28-24%) in the higher temperature range (35-40 degrees C). Increasing concentrations of either Zn2+, Fe3+, K+, and Mg2+ in the growth medium were associated with the increased CSH. Trypsin, pepsin, and proteinase K (75 to 150 micrograms.mL-1) reduced the CSH of isolate 12-94 cells. CSH was reduced, following exposure to DTT, SDS, Triton X-100, or Tween 80. Prolonged exposure of cells to starvation (60 days) also caused a significant decline in CSH. Several protein bands (18, 21, 23, 26 kDa) of the outer cell membrane were absent in 60-day starved cells compared to unstarved cells. In conclusion, our findings demonstrate that CSH of P. fluorescens isolates may contribute to nonspecific attachment/adhesion onto M. phaseolina hyphae/sclerotia, and the efficiency of adhesion is regulated by growth and other environmental conditions.
通过相排斥法、疏水相互作用色谱法（HIC）、静电相互作用色谱法（ESIC）和接触角测定的18株荧光假单胞菌土壤分离株的相对细胞表面疏水性（CSH）显示出很大程度的变异性。还检测了这些分离株的菌丝/菌核对菜豆壳球孢的粘附效率变化。选择了两株CSH最高（32.8%；分离株12 - 94）和最低（12%；分离株30 - 94）的分离株进行进一步研究。这些分离株对数生长早期至中期的细胞比稳定期的细胞疏水性更强，并且这些分离株的CSH也受温度和pH波动的影响。与较高温度范围（35 - 40℃）下较低的值（28 - 24%）相比，分离株12 - 94在30℃时表现出高CSH（32.3%）。生长培养基中Zn2 +、Fe3 +、K +和Mg2 +浓度的增加与CSH的增加相关。胰蛋白酶、胃蛋白酶和蛋白酶K（75至150微克·毫升-1）降低了分离株12 - 94细胞的CSH。暴露于二硫苏糖醇（DTT）、十二烷基硫酸钠（SDS）、吐温X - 100或吐温80后，CSH降低。细胞长时间暴露于饥饿状态（60天）也导致CSH显著下降。与未饥饿细胞相比，60天饥饿细胞的外细胞膜中几条蛋白带（18、21、23、26 kDa）缺失。总之，我们的研究结果表明，荧光假单胞菌分离株的CSH可能有助于其非特异性附着/粘附到菜豆壳球孢的菌丝/菌核上，并且粘附效率受生长和其他环境条件的调节。
