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Anti-oxidative Activity of Probiotic Lactobacillus rhamnosus 0908 Towards 2-Amino-3-methyl-3H-imidazo[4,5-f]quinoline (IQ) And 2-Amino-1-methyl-6-phenyl-1H-imidazo[4,5-b]pyridine (PhIP)
(Lodz University of Technology Press, 2015) Nowak, Adriana
Nowadays, humans are exposed to increasingly harmful xenobiotic substances which diffuse from the contaminated environment to food. Additionally, thermal processing of food, especially of meat, gives rise to pyrolytic products, such as heterocyclic aromatic amines (HAAs). HAAs may be linked to an increased cancer incidence in such organs as the colon, breast, stomach and liver. Carcinogenic mechanisms of HAAs include the initiation of tumours through reactive oxygen species (ROS) production, resulting in the formation of oxidised DNA bases, apurinic/apyrimidinic (AP) sites, or DNA strand breaks (Brown et al., 2014). ROS may participate in HAA-induced tumour development. HAAs can cause significant oxidative damage to DNA, lipids and proteins in the human body. The Lactobacillus bacteria are regarded as beneficial for host health, and they are most often used as probiotics. The human colon microbiota and probiotics are important factors that may play a major role in preventing colorectal cancer. One of the mechanism is antioxidative activity, which involves the detoxification of ROS (Koller et al., 2008).
In vitro anti-adherence effect of probiotic Lactobacillus strains on human enteropathogens
(Lodz University of Technology Press, 2017) Nowak, Adriana; Motyl, Ilona
Probiotic bacteria possess great potential for producing antimicrobial substances that inhibit and control pathogenic bacteria in the human gastrointestinal tract. The aim of this study was to determine the anti-adherence properties of the probiotic Lactobacillus strains Lb. rhamnosus ŁOCK 0900, Lb. rhamnosus ŁOCK 0908, and Lb. casei ŁOCK 0919 (individually and in a 1:1:2 mixture) against the reference pathogens Clostridium difficile (ATCC 9689), Enterococcus faecalis (ATCC 29212), Listeria monocytogenes (ATCC 19115), and Staphylococcus aureus (ATCC 6538) using the Caco-2 human colon adenocarcinoma cell line. The mixture of probiotic strains inhibited the adherence of all pathogens, from 10.2% for E. faecalis ATCC 29212 to 97.2% for L. monocytogenes ATCC 19115. Of all the tested probiotic strains, Lb. casei ŁOCK 0919 reduced the adherence of S. aureus ATCC 6538 to the greatest extent (by 45.9%). These results suggest that adherence inhibition may involve competition for eukaryotic cell receptors and probiotic bacteria could protect the host cells from pathogen colonization and disease.
Wzrost i przeżywalność bakterii probiotycznych w obecności heterocyklicznych amin aromatycznych
(Lodz University of Technology. Press, 2014) Nowak, Adriana
Heterocyclic aromatic amines (HCAs) ingested with heat-processed meat can contribute to colon cancer development. Those compounds interact with human intestinal microbiota. Under the research study, the effect was analyzed of IQ, MeIQx, or PhIP amines (each of them at 5 and 25 μg/ml concentration rates) on the growth (24 h cultivation in MRS broth) and survival (incubation for max. 120 h in a phosphate buffer) of four probiotic strains of Lactobacillus. It was found that no concentration level of the HCAs analyzed impacted the growth of bacteria. A higher concentration level of IQ (25 μg/ml) decreased the survival of Lb. casei 0900 after a 24 h period of incubation. MeIQx and PhIP also decreased the survival of Lb. paracasei 0919 after a 24 h period of incubation. Totally, the count of living cells decreased from 109 cfu/ml to 108 cfu/ml. Three strains were absolutely resistant to PhIP during a 120 h period of incubation. The results obtained prove that the probiotic bacteria studied maintain their high viability in the presence of the amines tested and, probably, they can bind together with them in human colon and, then, the aggregated particles are removed from the human body.