Authors:Ágnes Móricz, Nóra Adányi, Erzsébet Horváth, Péter Ott, and Ernő Tyihák
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
) in the inoculated layer, and performing densitometric and ex and
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
in the toxin spot was found. HCHO could also originate, among other sources, from demethylation of AFB1, which is apparent from the
spectra obtained in situ from the AFB1-containing spots. These results support the suggested role of HCHO and its reaction products with H
(e.g. singlet oxygen (
), ozone (O
)) in the antibacterial-toxic effect of AFB1.
Authors:Andrzej Skoczowski, Magdalena Troć, Anna Baran, and Małgorzata Baranska
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).
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 FouriertransformRamanspectroscopy band assignments on a
Authors:L. Velkoska-Markovska and B. Petanovska-Ilievska
chromatography (GC) [ 12 ], or by environmental friendly methods such as Fourier transform infrared spectroscopy (FTIR) [ 13 ] and FouriertransformRamanspectroscopy (FTRS) [ 14 ]. Collaborative International Pesticides Analytical Council (CIPAC) has published