| dc.description.abstract | Alkylphenol polyethoxylates (APEOs) are non-ionic surfactants that have been used in the household and as industrial detergents for more than 40 years. Triton X-100 belongs to the octylphenol polyethoxylates, and their metabolism intermediates such as octylphenol and octyl phenol monoethoxylate have been proved the environmental hormone. A bacterial strain, Pseudomonas nitroreducens TX1 was previously isolated from the sediments of drainage near the dormitory of National Central University in Taiwan. The bacterial strain is able to use Triton X-100 as the sole carbon and energy source to grow. This study was aimed to use 2D gel electrophoresis-based proteomic approach to identify proteins up- and down-regulated by 0.5% and 20% Triton X-100 in P. nitroreducens TX1, respectively. Results showed that there are about 500 protein spots from the pI 4-7 gels for P. nitroreducens TX1 grown under minimal salts basal medium (MSB) containing 0.5% Triton X-100 (experiment group) and about 600 spots for cells grown under 0.5% succinate as the sole carbon source (control group). 600 spots for cells grown under 20% Triton X-100 as the sole carbon source (experiment group). Moreover, the matrix-assisted laser desorption ionization-quadruples-time of fly mass spectrometer (MALDI-Q-TOF MS) was used to identify the proteins separated by two dimension gel electrophoresis (2DE). In the case of 0.5% Triton X-100, there are 17 up-regulated proteins and 11 down-regulated proteins were identified. Among the up-regulated proteins, several classes of proteins were found: (1) Six proteins were found putative ATP binding cassette (ABC) transporters, including two main classes of ABC transporters. One of the classes, the Leu/ Ile/ Val-binding protein family was suggested to involve in the transportation of Triton X-100; (2) Three were found the stress-responsive proteins (GroEL, ClpB, IbpA), which perform the function of chaperone meditating protein folding; (3) The alkyl hydroperoxide reductase (AhpC), which was first discovered in surfactant stress response; (4) Other stress proteins (TerD, TerE), which are presumed to relate to oxidative stress; (5) The K+ transporters KdpD and KdpE are highly expressed while the osmotic regulator OmpR was depressed, which suggest there may exist osmotic control system in the presence of Triton X-100. (6) One of the up-regulated enzyme is dihydrolipoamide dehydrogenase. It is related to the energy synthesis and catalyze the transformation of acetyl CoA from pyruvate. On the other hand, down-regulated enzymes are involved in the fatty acid synthesis, DNA biosynthesis and serine synthesis. The proteins up-regulated by 20% Triton X-100 were further studied in comparison to 0.5% Triton X-100. Up-regulated proteins included ATP synthetase, flagellin and fatty synthesis related proteins. Malate synthetase, one of key enzyme involved in the glyoxylate cycle, which catalyzes glyoxylate to malate was down-regulated, These suggested the degradation of polyethoxylate chain in Triton X-100 is less likely to generate glyoxylate. However, study founded acetaldehyde inhibit the expression of PhoP protein, which familiar to our experiment. It suggested the degradation of polyethoxylate side chain in Triton X-100 is more likely to from acetaldehyde. | en_US |