FTIR study of the effect of nTiO2 on the biochemical constituents of gill tissues of Zebrafish (Danio rerio).

In the present study, an attempt is made to assess the changes in the biochemical contents in general, and the protein structural changes in particular, in the gill tissues of Zebrafish (Danio rerio) due to titanium nanoparticles and their bulk counterpart using FTIR spectroscopy. The FTIR spectra show that the intensity differences between the control and titanium-exposed tissues are remarkable. For example, TiO(2)-exposed tissues show higher intensities at amide I and amide II of proteins, but lower at 2924 cm(-1) (CH(2) asymmetric stretching of lipids), 2853 cm(-1) (CH(2) symmetric stretching of lipids) and 1744 cm(-1) (CO stretching of phospholipids) when compared with the control tissues. This suggests that there is an increase or decrease in the percentage of a certain types of biomolecules relative to the total infrared-active constituents in the gill tissues. The curve-fitting analysis suggests an increase in alpha-helical structure and a decrease in beta-sheet structure due to TiO(2) exposure. These results confirm that the structural conformation of proteins in fish gill tissues was significantly influenced by TiO(2) exposure. Further, the changes are more due to nTiO(2) when compared to TiO(2) bulk, suggesting that nTiO(2) are affecting the biochemical constituents more than their bulk counterpart.

The study of the changes in the biochemical and mineral contents of bones of Catla catla due to lead intoxication.

In the present study, an attempt has been made to analyze the changes in the biochemical and mineral contents of lead-intoxicated bones of Catla catla at subchronic (15.5 ppm) exposure, and also to determine whether the effects of Pb intoxication can be reversed with the chelating agent meso 2, 3-dimercaptosuccinic acid (DMSA) on the bones of freshwater fingerlings Catla catla by using Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and atomic absorption spectrophotometer techniques. The FT-IR spectra of the lead-exposed bones show significant alteration in the biochemical constituents. The XRD analysis showed a decrease in crystallinity due to lead exposure. Further, the Ca, Mg, and P contents of the lead-exposed bones were less than those of the control group, and there was an increase in the mineral contents of the bones after DMSA treatment. In conclusion, the present study suggests that the subchronic lead exposure results in severe loss of bone minerals. The overall decrease in the FT-IR band intensity of Pb-exposed bones relative to the control indicates a decrease in the biochemical constituents like proteins and lipids. The increase in the band intensity after treatment with chelating agent DMSA indicates increased biochemical constituents, showing that the subchronic effects of lead can be reversed by DMSA. The amide I bands observed at 1654 cm(-1) in the present study suggest that the protein is dominated by alpha-helical structure.

Bioaccumulation and depuration of chromium in the selected organs and whole body tissues of freshwater fish Cirrhinus mrigala individually and in binary solutions with nickel.

Contamination of aquatic ecosystems with heavy metals has been receiving increased worldwide attention due to their harmful effects on human health and other organisms in the environment. Most of the studies dealing with toxic effects of metals deal with single metal species, while the aquatic organisms are typically exposed to mixtures of metals. Hence, in order to provide data supporting the usefulness of freshwater fish as indicators of heavy metal pollution, it has been proposed in the present study to investigate the bioaccumulation and depuration of chromium in the selected organs of freshwater fingerlings Cirrhinus mrigala, individually and in binary solutions with nickel. The results show that the kidney is a target organ for chromium accumulation, which implies that it is also the "critical" organ for toxic symptoms. The results further show that accumulation of nickel in all the tissues of C. mrigala is higher than that of chromium. In addition, the metal accumulations of the binary mixtures of chromium and nickel are substantially higher than those of the individual metals, indicating synergistic interactions between the two metals. Theoretically the simplest explanation for an additive joint action of toxicants in a mixture is that they act in a qualitatively similar way. The observed data suggest that C. mrigala could be suitable monitoring organisms to study the bioavailability of water-bound metals in freshwater habitats.

The effect of arsenic exposure and the efficacy of DMSA on the proteins and lipids of the gill tissues of Labeo rohita.

Arsenic is a naturally occurring, highly toxic environmental pollutant. Fourier transform infrared (FT-IR) spectroscopy is a non-disturbing technique which provides quantitative information about the molecular composition of biological samples. The aim of this work is to study the compositional and structural changes at the molecular level occurring in gill tissues of Labeo rohita fingerlings due to arsenic exposure for various exposure periods by using FT-IR spectroscopic technique. The results of the present study suggest that arsenic exposure causes significant changes on the major biochemical constituents such as proteins, lipids and nucleic acids in the gill tissues of L. rohita. The changes are more pronounced as the period of exposure is increased. The significant decrease in the intensity and area of the amide I peak and CH(3) asymmetric stretching band suggests an alteration in the protein profile and lipid levels respectively, due to arsenic exposure. The amide A peak shifts suggests a change in the level of protein amide hydrogen bonding due to arsenic exposure. Further, the treatment with meso-2,3-dimercaptosuccinic acid (DMSA) improves the levels of biochemical constituents significantly, which suggest that DMSA treatment reduces the toxic effects and helps the recovery of gill tissues and its return to the level of the control.

Morphological changes due to Lead exposure and the influence of DMSA on the gill tissues of the freshwater fish, Catla catla.

Catla catla fingerlings were reared in freshwater and exposed to 15.5 ppm concentration of lead for 60 days. The morphological changes on the gill of the C. catla fingerlings due to lead intoxication and the effect of DMSA (meso 2,3-dimercaptosuccinic acid) on the affected tissues were observed using Scanning Electron Microscope. It has been found that the lead treated gill tissues showed certain marked changes, such as cell hypertrophy, alteration in the lamellar surfaces, epithelial hyperplasia and the fusion of adjacent lamellae. The antidote DMSA treatment reduces the toxic effects and helps the recovery of gill tissue and its return to the level of the control/normal.