Laboratory of Biochemistry, Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, 410049 Saratov, Russia.
Molecules. 2021 Feb 21;26(4):1146. doi: 10.3390/molecules26041146.
To demonstrate the importance of sample preparation used in Fourier transform infrared (FTIR) spectroscopy of microbiological materials, bacterial biomass samples with and without grinding and after different drying periods (1.5-23 h at 45 °C), as well as biogenic selenium nanoparticles (SeNPs; without washing and after one to three washing steps) were comparatively studied by transmission FTIR spectroscopy. For preparing bacterial biomass samples, Sp7 and Sp245 (earlier known as Sp245) were used. The SeNPs were obtained using Sp7 incubated with selenite. Grinding of the biomass samples was shown to result in slight downshifting of the bands related to cellular poly-3-hydroxybutyrate (PHB) present in the samples in small amounts (under ~10%), reflecting its partial crystallisation. Drying for 23 h was shown to give more reproducible FTIR spectra of bacterial samples. SeNPs were shown to contain capping layers of proteins, polysaccharides and lipids. The as-prepared SeNPs contained significant amounts of carboxylated components in their bioorganic capping, which appeared to be weakly bound and were largely removed after washing. Spectroscopic characteristics and changes induced by various sample preparation steps are discussed with regard to optimising sample treatment procedures for FTIR spectroscopic analyses of microbiological specimens.
为了展示在微生物材料的傅里叶变换红外（FTIR）光谱学中样品制备的重要性，对具有和不具有研磨且经过不同干燥期（45°C 下 1.5-23 小时）的细菌生物量样品，以及未经洗涤和洗涤一至三个洗涤步骤后的生物源硒纳米颗粒（SeNPs）进行了比较研究，采用透射 FTIR 光谱法。为了制备细菌生物量样品，使用了 Sp7 和 Sp245（以前称为 Sp245）。通过用亚硒酸盐孵育 Sp7 获得了 SeNPs。结果表明，对生物质样品进行研磨会导致与细胞多聚 3-羟基丁酸（PHB）相关的谱带轻微下移，其存在量较小（约 10%以下），反映了其部分结晶化。结果表明，干燥 23 小时可使细菌样品的 FTIR 光谱更具重现性。结果表明，SeNPs 含有蛋白质、多糖和脂质的外壳层。所制备的 SeNPs 在其生物有机外壳中含有大量的羧基化成分，这些成分似乎结合较弱，在洗涤后大部分被去除。讨论了各种样品制备步骤引起的光谱特征和变化，以优化用于微生物样品 FTIR 分析的样品处理程序。
