Impact of Exopolysaccharides (EPSs) of Lactobacillus gasseri strains isolated from human vagina on cervical tumor cells (HeLa).

Lactobacilli, commonly used as probiotics, have been shown to maintain vaginal health and contribute to host microbiota interaction. Exopolysaccharides (EPSs) produced by lactobacillus have been found to have an important role in probiotic activity; however, there is limited knowledge concerning their impact on cervical cancer and urogenital health. The objective of this study is to investigate and compare EPSs of L. gasseri strains (G10 and H15), isolated from a healthy human vagina, for their capability to inhibit cervical cancer cell (HeLa) growth and modulate immune response. HeLa cells were treated with live culture at ∼108 CFU/ml or increasing concentration of lyophilized EPS (L-EPS) (100, 200, or 400 µg/ml) of L. gasseri strains and their ability to adhere to host cells, inhibit proliferation, and modulate immune response were evaluated. Additionally, monosaccharide composition of the L-EPSs produced by L. gasseri strains was determined by HPLC. The sugar component was the same; however, relative proportions of the individual monosaccharides except mannose were different. Although they both produce similar amount of EPS, the most adhesive strain was G10. Both live and L-EPS of L. gasseri strains were capable of inhibiting the cell proliferation of HeLa cells with the impact of L-EPS being strain specific. L-EPSs of L. gasseri strains induced apoptosis in HeLa cells in a strain dependent manner. The ability to induce apoptosis by G10 associated with an upregulation of Bax and Caspase 3. L. gasseri strains showed an anti-inflammatory impact on HeLa cells by decreasing the production of TNF-α and increasing the IL-10 production. In conclusion, diversity in sugar composition of EPS might contribute to adhesion and proliferation properties. Although our results suggest a relationship between the ability of a strain to induce apoptosis and its sugar composition of EPS, further research is required to determine the probiotic mechanisms of action by which L. gasseri strains result in strain specific anti-proliferative activity.

[Detection of Cryptosporidium spp. in feces with nested PCR and carbol fuchsin staining method]. / Cryptosporidium spp'nin Diskidan Nested PCR ve Carbol Fuchsin Boyama Yöntemi ile Teshis Edilmesi.

This study was carried out on 45 stool specimens, consisting of 18 samples from children with diarrhea and 27 samples from diarrheic calves. Samples were screened by both carbol fuchsin staining and nested PCR for presence of Cryptosporidium spp. Using the carbol fuchsin staining method, we detected a total of 4 (8.9%) positive samples out of 45; of these 3 (11.2%) were from calf samples and 1 (5.6%) from a child. Nested PCR detected a total of 9 (20.0% positive samples out of 45 including 8 (29.7%) from calf samples and 1 (5.6%) from a child. Although the staining method revealed a 100% specificity, it was deficient in sensitivity (44.0%) compared to nested PCR. The study showed that nested PCR is an acceptable method for studying the etiology of doubtful diarrheal cases.