Cyst formation Cilengitide manufacturer might be due to depletion of nutrients exhausting by dividing protozoa. The presence of L. monocytogenes significantly accelerated protozoan encystment. Thus, on day 7 a four-fold increase in cyst concentration compared to the control culture was observed (p < 0.05). By the end of week 2 at least twice as more cysts compared to control and no vegetative cells were revealed in association with L. monocytogenes. To examine whether the observed effects are characteristic for wild type L. monocytogenes and were not associated with specific toxicity of the EGDe strain, four additional L. monocytogenes strains were tested. The previously described wild type strains
VIMVR081, VIMVW039, VIMHA034, and VIMVF870 isolated from a wild
rodent, environment, human, and food, respectively, were used [5]. All L. monocytogenes strains tested reduced trophozoite concentrations on day 7 (Figure selleck chemicals 3). In contrast, the number of cysts increased in the co-culture. Thus, wild type L. monocytogenes caused mortality and induced encystment in T. pyriformis. Figure 3 The effect of various L. monocytogenes strains on the T. pyriformis population. T. pyriformis trophozoite (while columns) and cyst (black columns) concentrations are shown on day 7 of co-cultivation with various L. monocytogenes strains designated on the figure, or without bacteria (w/o bacteria). The mean values ± SE from two experiments made in triplicate are shown.*
p < 0,05; **p < 0,005. LLO absence diminishes L. monocytogenes cytotoxic effect on T. pyriformis and prevents induction of protozoan encystment Using LLO specific antibodies, we observed that LLO expression was low but detectable in the conditions used (the LB broth at 28°C) (Figure 4A). Therefore, these conditions permitted us to examine a LLO contribution into the interactions between L. monocytogenes and T. pyriformis. Figure 4 Changes in the T. pyriformis population in the co-culture with L. monocytogenes in dependence on L. monocytogenes LLO production. A. Detection of LLO in the culture supernatant of L. monocytogenes grown in the LB broth at 28°C. Proteins from 0,5 ml were loaded in each lane. On the left, secreted proteins are separated onto 10 % SDS-PAGE gel and visualized of by staining with Coomassie Brilliant Blue R-250; on the right, Western blot analysis of secreted proteins with LLO-specific antiserum; 1 – wild type EGDe strain; 2 – EGDeΔhly strain carrying the vector pTRKL2; 3 – EGDeΔhly strain carrying the plasmid pHly. Numbers show molecular weight standard positions. The arrow shows a LLO position (MWLLO 58 kDa). B. Trophozoite (left) and cyst (right) concentrations related to LLO production: designations for columns are shown on the figure. The mean values ± SE from two experiments made in triplicate are shown. * p < 0,05.