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

Structural and compositional features of bacterial cell samples and of lipo polysaccharide-protein complex isolated from the cell surface of the plant- growth-promoting rhizobacterium Azospirillum brasilense (wild-type strain S p7) were characterised using Fourier transform (FT) Raman spectroscopy. The structural spectroscopic information obtained is analysed and considered t ogether with analytical data on the content of metal cations (Co2+, Cu2+ an d Zn2+) in the bacterial cells grown in a standard medium as well as in the presence of each of the cations (0.2 mM). The latter, being taken up by ba cterial cells from the culture medium in significant amounts, were shown to induce certain metabolic changes in the bacterium revealed in FT-Raman spe ctra, which is discussed from the viewpoint of bacterial response to enviro nmental stresses. (C) 2001 Elsevier Science B.V. All rights reserved.