Search Results

You are looking at 1 - 4 of 4 items for :

  • " Fourier -transform Raman spectroscopy" x
  • All content x
Clear All

Bioautography can be extended to a complex system called BioArena by linking different steps to it, for example dissolving a variety of compounds in the cell suspension to affect biological activity, measuring putative mediators of antibiosis, for example formaldehyde (HCHO) and hydrogen peroxide (H 2 O 2 ) in the inoculated layer, and performing densitometric and ex and in situ spectroscopic examination to follow the changes in the inhibition zones and active compounds (e.g. antibiotics and toxins). Possibilities of the basic elements of BioArena system are illustrated in this paper by results with aflatoxin B1 (AFB1). Target bacterial cells in the logarithmic growth phase were found to be the most sensitive for direct bioautography. Densitometric signals of bioautograms (negative densitometry) of 0.125–1 μg AFB1 spots showed logarithmic correlation with the amount of AFB1. The HCHO capturer L-arginine decreased whereas the HCHO generator-mobilizer Cu(II) ions increased the antibacterial-toxic effect of AFB1. The latter effect was also confirmed by negative densitometry. Besides higher levels of HCHO, a decrease of H 2 O 2 in the toxin spot was found. HCHO could also originate, among other sources, from demethylation of AFB1, which is apparent from the Fourier transform Raman spectra obtained in situ from the AFB1-containing spots. These results support the suggested role of HCHO and its reaction products with H 2 O 2 (e.g. singlet oxygen ( 1 O 2 ), ozone (O 3 )) in the antibacterial-toxic effect of AFB1.

Restricted access

second measurement (with NaOH and without CO 2 – was conducted for 15 min. All measurements were performed in four replicates. Results were converted to dry mass (per gram). Fourier transform Raman spectroscopy measurements

Restricted access
Journal of Thermal Analysis and Calorimetry
Authors: Blaž Likozar, Romana Cerc Korošec, Ida Poljanšek, Primož Ogorelec, and Peter Bukovec

-dimensionally cross-linked network to which part of the urea residues are linked as pendants or grafts. They proposed this model as the polymeric structure of the MUF resin. Scheepers et al. [ 3 ] based Fourier transform Raman spectroscopy band assignments on a

Restricted access

chromatography (GC) [ 12 ], or by environmental friendly methods such as Fourier transform infrared spectroscopy (FTIR) [ 13 ] and Fourier transform Raman spectroscopy (FTRS) [ 14 ]. Collaborative International Pesticides Analytical Council (CIPAC) has published

Open access