Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) represents a simple reliable approach for rapid bacterial identification based on specific peptide/protein fingerprints. However, cell-wall characteristics of mycobacterial species, and their well known stability, complicate MALDI-TOF MS profiling analysis. In this study, we tested two recently published protocols for inactivation and disruption of mycobacteria, and we also examined the influence of different culture conditions (four culture media and five cultivation times) on mass spectral quality and the discriminatory power of the method. We found a significant influence of sample pretreatment method and culture medium on species identification and differentiation for a total of 10 strains belonging to Mycobacterium phlei and Mycobacterium smegmatis. Optimum culture conditions yielding the highest identification success rate against the BioTyper database (Bruker Daltonics) and permitting the possibility of automatic acquisition of mass spectra were found to be distinct for the two mycobacterial species examined. Similarly, individual changes in growth conditions had diverse effects on the two species. For these reasons, thorough control over cultivation conditions should always be employed to maximize the performance and discriminatory power of MALDI-TOF MS profiling, and cultivation conditions must be optimized separately for individual groups of mycobacterial species/strains.
A microtiter plate-based assay was developed for the automatic monitoring of degradation profile of the yellow-coloured nitrophenolic compounds. The method enables to reduce the intervals between measurements of substrate concentration to minutes and to overcome the problem of discontinuity of sampling typical for conventional methods. The concentrations of nitrophenolic compounds were calculated from the absorbance values determined automatically by BIOSCREEN C. Verification of the method was based on the comparison of results with the conventional HPLC method results. The values of the rate and saturation constants were comparable for both the microtiter plate-based assay and the conventional HPLC method. The automatic method described here seems to be efficient for the screening degradation studies, which requires the treatment of quantity of samples.
- MeSH
- Arthrobacter izolace a purifikace metabolismus růst a vývoj MeSH
- bakteriologické techniky metody přístrojové vybavení MeSH
- biodegradace MeSH
- financování organizované MeSH
- katecholy metabolismus MeSH
- kinetika MeSH
- kultivační média MeSH
- molekulární sekvence - údaje MeSH
- nitrofenoly metabolismus MeSH
- půdní mikrobiologie MeSH
- Rhodococcus genetika izolace a purifikace klasifikace metabolismus MeSH
- sekvenční analýza DNA MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Publikační typ
- hodnotící studie MeSH
