de Carvalho Carla C C R, da Cruz Alexandra A R L, Pons Marie-Nöelle, Pinheiro Helena M R V, Cabral Joaquim M S, da Fonseca M Manuela R, Ferreira Bruno S, Fernandes Pedro
Centro de Engenharia Biológica e Química, Instituto Superior Técnico, 1049-001 Lisboa, Portugal.
Microsc Res Tech. 2004 Jun 15;64(3):215-22. doi: 10.1002/jemt.20061.
This work aimed at studying the behavior and tolerance of Mycobacterium sp. NRRL B-3805, Rhodococcus erythropolis DCL14 and Pseudomonas putida S12 cells in the presence of various concentrations of water miscible (ethanol, butanol, and dimethylformamide, up to 50% v/v) and water immiscible solvents (dodecane, bis(2-ethylhexyl) phthalate and toluene, up to 5% v/v). When incubated in the presence of these solvents, the cells were found to have lower tolerance to butanol and toluene than to the remaining solvents. Nevertheless, the concentrations of solvents endured by the tested strains show that they are quite solvent-tolerant, confirming their potential as biocatalysts in nonconventional systems. Microscopic observation of samples showed that the hydrophobic Mycobacterium sp. and R. erythropolis cells were able to aggregate to protect the population under stress conditions. Comparison of the results obtained at the single cell level by fluorescence microscopy and colony development on agar plates indicated that the primary effects of most solvents tested were on the cell membrane and replicating capability of the cells.
这项工作旨在研究在不同浓度的与水混溶的溶剂（乙醇、丁醇和二甲基甲酰胺，体积分数高达50%）和与水不混溶的溶剂（十二烷、邻苯二甲酸二（2-乙基己基）酯和甲苯，体积分数高达5%）存在的情况下，分枝杆菌属NRRL B-3805、红平红球菌DCL14和恶臭假单胞菌S12细胞的行为和耐受性。当在这些溶剂存在的情况下进行培养时，发现细胞对丁醇和甲苯的耐受性低于对其余溶剂的耐受性。然而，受试菌株所能耐受的溶剂浓度表明它们具有相当高的耐溶剂性，证实了它们作为非常规体系中生物催化剂的潜力。对样品的显微镜观察表明，疏水性的分枝杆菌属和红平红球菌细胞能够聚集起来，以在应激条件下保护群体。通过荧光显微镜在单细胞水平上获得的结果与在琼脂平板上菌落发育情况的比较表明，大多数受试溶剂的主要作用是针对细胞膜和细胞的复制能力。
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