Antitumour and apoptotic effects of a novel Tris-peptide complex obtained after isolation of Raoultella ornithinolytica extracellular metabolites.

AIMS: The characterization of the antitumour activity and chemical identification of the compounds obtained after the isolation of extracellular metabolites of bacteria Raoultella ornithinolytica. METHODS AND RESULTS: The fraction with anticancer activity against the HeLa cell line, T47D and TOV-112D was obtained from the supernatants of R. ornithinolytica culture using ion-exchange chromatography, and separated by Sephadex G-50 medium gel filtration into two subfractions. The obtained compounds were analysed using Fourier Transform-Infrared Spectroscopy, Raman spectroscopy and matrix-assisted laser desorption/ionization MS/MS spectrometry. The antitumour activity of the two subfractions was analysed using 5-bromo-2-deoxy-uridine kit. The subfraction with the highest activity against HeLa cells was identified as Tris-peptide complex. The amino acid sequence of the peptide from the complex was found to be TDAPSFSDIPN and molecular weight was estimated at 1430·6576 Da. Cytotoxic, cytopathic and apoptotic effects in HeLa cells treated with the active complex were observed; however, the cytotoxic effect against normal human skin fibroblasts was minimal. CONCLUSIONS: The Tris-peptide complex from R. ornithinolytica showed selective antitumour activity against the HeLa cell line. SIGNIFICANCE AND IMPACT OF THE STUDY: The Tris-peptide complex due to the high selectivity can be used in biomedicine, and its derivatives may contribute to the development of new anticancer compounds.

Anti-Candida albicans action of the glyco-protein complex purified from metabolites of gut bacterium Raoultella ornithinolytica isolated from earthworms Dendrobaena veneta.

AIMS: The aim of our research was to isolate the compounds from the metabolites of Raoultella ornithinolytica with the activity against Candida albicans and to analyse the action of the compounds on the metabolic activity and morphology of the fungus cells. METHODS AND RESULTS: The effect of active protein fractions on the cell morphology, growth, and metabolic activity of C. albicans was analysed under a light microscope with Nomarski contrast and after staining with calcofluor-white. The LIVE/DEAD Yeast Viability Kit F-7030 FUN 1 was used for determination of C. albicans metabolic activity. The biomolecules obtained after isolation by ion exchange chromatography were further fractionated by Sephadex G-50 medium gel filtration. Then, after molecular sieve, the fractions were analysed by FTIR and SERS Spectroscopy. A subfraction was isolated from the antifungal protein fraction above 100 kDa. The active subfraction identified as the glyco-protein complex caused a decrease in the metabolic activity and morphological changes of C. albicans cells. CONCLUSIONS: The glyco-protein complex obtained from metabolites of bacteria Raoultella ornithinolytica possesses antifungal activity against C. albicans and shows minimal toxicity (1%) against fibroblasts. SIGNIFICANCE AND IMPACT OF THE STUDY: Studies on the glyco-protein complex obtained from earthworm gut bacteria R. ornithinolytica can lead to their application in biological fungicide and pharmaceutical industry.