Biomolecular changes in gills of Gambusia affinis studied using two dimensional correlation infrared spectroscopy coupled with chemometric analysis

Abstract

The pesticide use in agriculture production at reduced cost results in increased usage. Excessive use of this is en-routed to the aquatic environment causing serious threats. Fishes are used as a bioindicator of toxicants due to pollution in the aquatic environment. These are suitable biomarkers for assessment in the ecosystem. Hence the study of pesticides toxicity in fish provides useful information about the aquatic biota. 2DCOS infrared spectral analysis gives fine spectral resolutions of overlapping bands. The enhancement in spectral resolution and overlapping bands in second dimensions is an advantage in interpreting complex spectra. The synchronous 2DCOS spectra show amide of proteins as a predominant occurring followed by phospholipids esters of fatty acids at 1771 cm−1. The asynchronous +ve and -ve cross peaks +(1651, 1691) and – (1623, 1651) results in an overlapped contribution of β sheet (1691 cm−1) with a decrease in α helix (1651 cm−1) of protein secondary structure. The principal component analysis (PCA) shows samples are well discriminated with a high loading value for 0.51 ppb (T3) treatment. The hierarchical analysis shows clustering of samples identical in nature. The Receiver Operation Characteristic analysis (ROC) validates experimental outcome as measured from the area under the curve.