Toxicoproteomic analysis of human lung epithelial cells exposed to steel industry ambient particulate matter (PM) reveals possible mechanism of PM related carcinogenesis.

Toxicoproteomic analysis of steel industry ambient particulate matter (PM) that contain high concentrations of PAHs and metals was done by treating human lung cancer cell-line, A549 and the cell lysates were analysed using quantitative label-free nano LC-MS/MS. A total of 18,562 peptides representing 1576 proteins were identified and quantified, with 196 proteins had significantly altered expression in the treated cells. Enrichment analyses revealed that proteins associated to redox homeostsis, metabolism, and cellular energy generation were inhibited while, proteins related to DNA damage and repair and other stresses were over expressed. Altered activities of several tumor associated proteins were observed. Protein-protein interaction network and biological pathway analysis of these differentially expressed proteins were carried out to obtain a systems level view of proteome changes. Together it could be inferred that PM exposure induced oxidative stress which could have lead into DNA damage and tumor related changes. However, lowering of cellular metabolism, and energy production could reduce its ability to overcome these stress. This kind of disequilibrium between the DNA damage and ability of the cells to repair the DNA damage may lead into genomic instability that is capable of acting as the driving force during PM induced carcinogenesis.

Determination of total chromium in tannery waste water by inductively coupled plasma-atomic emission spectrometry, flame atomic absorption spectrometry and UV-visible spectrophotometric methods.

The determination of total chromium in different streams of tannery effluents were carried out by the digestion of samples in a HNO(3)/H(2)SO(4) mixture followed by KMnO(4) oxidation, which resulted in the complete conversion of Cr(III) to Cr(VI). The Cr(VI) (Cr(2)O(7)(2-)) species present in these samples were estimated by inductively coupled plasma-atomic emission spectrometry (ICP-AES), flame atomic absorption spectrometry (FAAS) and UV-visible spectrophotometry (1,5-diphenyl carbazide method). The results obtained from these methods were critically evaluated. UV-visible spectrophotometry was found to be better suited for this analysis when compared with the other two methods. Since these solutions contain relatively high concentrations of chromium (200-2400 mg/l), the need for preconcentration did not arise. The higher values obtained in the case of ICP-AES and FAAS methods can be attributed to the matrix effect arising out of high concentration of mineral acids and electrolytes. In addition, the values obtained in the latter methods (ICP-AES and FAAS) are comparable with each other, indicating that the interferences influence the results almost equally in both techniques. The statistical treatment of data indicates that the differences between the methods are within the acceptable range.