Spectroscopic analysis of bacterial biological warfare simulants and the effects of environmental conditioning on a bacterial spectrum

The ability to distinguish bacteria from mixed samples is of great interest, especially in the medical and defence arenas. This paper reports a step towards the aim of differentiating pathogenic endospores in situ, to aid any required response for hazard management using infrared spectroscopy combined with multivariate analysis. We describe a proof-of-principle study aimed at discriminating biological warfare simulants from common environmental bacteria. We also report an evaluation of multiple pre-processing techniques and subsequent differences in cross-validation of two pattern recognition models (Support Vector Machines and Principal Component–Linear Discriminant Analysis) for a six-class classification (bacterial classification). These classifications were possible with an average sensitivity of 88.0 and 86.9 %, and an average specificity of 97.6 and 97.5 % for the SVM and the PC-LDA models, respectively. Most spectroscopic models are built upon spectra from bacteria that have been specifically prepared for analysis by a particular method; this paper will comment upon the differences in the bacterial spectrum that occur between specific preparations when the bacteria have spent 30 days in the simulated weather conditions of a hot dry climate

The effect of white sturgeon (Acipenser transmontanus) ovarian fat deposition on caviar yield and nutritional quality: introducing image processing method for sturgeon ovary fat determination

Image analysis can predict the fat content of sturgeon ovaries that had been categorized as having a low, medium, and high fat content based upon the caviar yield expressed as a percent of the total ovary weight, and were correlated with the chemical measurement of total fat (R 2 = 0.83). The fatty acid composition of eggs was not influenced by ovary fat content. Palmitic acid (16:00) was the most abundant saturated fatty acid and oleic acid (18:1n-9) the most predominant monounsaturated fatty acids in sturgeon eggs regardless of the ovary fat content. No significant differences (P > 0.05) were observed in docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) in eggs from fish with different fat ovaries. Fourier transform infrared spectroscopy (FT-IR) coupled with principal component analysis indicated no significant difference in chemical compositions in sturgeon eggs separated from ovaries of different fat contents confirming the fatty acid composition results