Fourier transform Raman spectroscopic characterisation of cells of the plant-associated soil bacterium Azospirillum brasilense Sp7

Molecular Diversity of Sea Spray Aerosol Particles: Impact of Ocean Biology on Particle Composition and Hygroscopicity

“…[4][5][6]9,14,22 The OM fraction of SSA depends on size and varies in composition; field studies have reported that the majority of OM in the bulk submicrometer marine aerosol is relatively water insoluble and that in supermicrometer SSA is mostly water soluble. [12][13][14][23][24][25][26] Spectroscopic measurements of SSA particles collected in the field have shown that the oxygen-rich organic fraction of individual particles contains molecules with spectral signatures that are characteristic of saccharides, 24 and signatures for carboxylic acids 26 and alkanes 27 have also been observed.…”

“…16,21,22,28,29 However, in some cases, weak correlations between levels of chlorophyll a and organic content in SSA have been observed. 13,21,27 Recent studies have shown that bacteria-driven alterations of seawater composition lead to changes in both the external and internal mixing state of SSA, as well as particle hygroscopicity. 9,11,14,[30][31][32] In an effort to provide more detail on the complex molecular composition of individual SSA, we utilized micro-Raman spectroscopy in this study to measure the vibrational spectra of individual freshly emitted SSA particles that had been generated via wave breaking under ocean-relevant bloom conditions in an enclosed wave flume.…”

“…24,25 The SSA spectrum categorized as polysaccharides (Figure 1f) features skeletal C-C, C-O and stretching C-C-O bands at 991 and 1044 cm -1 , CH2 bending vibration that typically appears at 1459 cm -1 in lipids, a peak at 1642 cm -1 that can be either C=O stretching in carbohydrates or C=C stretching vibration of unsaturated fatty acid chains and a broad peak at 2929 cm -1 identified as the C-H stretching modes of -CH-, methylene (-CH2-) and terminal methyl (-CH3) groups of fatty acid chains. 26,27 This spectrum obtained from SSA was compared with the spectrum of commercially available standards representative of cellular polysaccharides: lipopolysaccharide (LPS) from E. coli, lamanarin, inulin, sodium alginate and peptidoglycan. For a quantitative comparison of the spectra from SSA with the spectra obtained from the standards of cellular polysaccharides, χ 2 errors between two spectra were determined for the 550-4000 cm -1 spectral range (see Figure S8).…”

Trace cobalt speciation in bacteria and at enzymic active sites using emission Mössbauer spectroscopy

“…Azospirillum brasilense Sp245 was cultivated in a standard mineral medium as described elsewhere [9,18,19,20], with 5 mmol L -1 NH 4 Cl as a nitrogen source and 0.6% sodium malate as a carbon source (pH 6.9). For EMS studies of Co 2+ -treated cells, the bacterial culture was grown up to ca.…”

“…Our previous studies on the plant growth-promoting rhizobacterium Azospirillum brasilense have shown that 0.2 mmol L -1 cobalt(II) in the culture medium taken up by the bacterium can induce some metabolic changes in the latter as a response to metal stress [18,19]. Co 2+ was also shown to support the activity of glutamine synthetase (GS, a key enzyme of nitrogen metabolism) from this bacterium [9,20].…”