|
|
|
|
|
|
Pyruvate Decarboxylase, the Target for Omeprazole in Metronidazole-Resistant and Iron-Restricted Tritrichomonas foetus. Róbert Sutak, 2004.The substituted benzimidazole omeprazole, used for the treatment of human peptic ulcer disease, inhibits the growth of the metronidazole-resistant bovine pathogen Tritrichomonas foetus in vitro (MIC at which the growth of parasite cultures is inhibited by 50%, 22 µg/ml [63 µM]) . The antitrichomonad activity appears to be due to the inhibition of pyruvate decarboxylase (PDC), which is the key enzyme responsible for ethanol production and which is strongly upregulated in metronidazole-resistant trichomonads . PDC was purified to homogeneity from the cytosol of metronidazole-resistant strain . The tetrameric enzyme of 60-kDa subunits is inhibited by omeprazole (50% inhibitory concentration, 16 µg/ml) . Metronidazole-susceptible T . foetus, which expresses very little PDC, is only slightly affected . Omeprazole has the same inhibitory effect on T . foetus cells grown under iron-limited conditions . Similarly to metronidazole-resistant cells, T . foetus cells grown under iron-limited conditions have nonfunctional hydrogenosomal metabolism and rely on cytosolic PDC-mediated ethanol fermentation . Production and Properties of Bacteriocin-Like Inhibitory Substances from the Swine Pathogen Streptococcus suis Serotype 2. D. Mélançon, 2003.Streptococcus suis serotype 2 is a major pathogen found in the upper respiratory tract of swine . In this study, isolates of this bacterial species were tested for the production of bacteriocin-like inhibitory substances (BLIS) . Of the 38 strains tested, four inhibited the growth of other S . suis isolates according to a deferred-antagonism plate assay . Interestingly, three of the strains were originally isolated from healthy carrier pigs and were considered nonvirulent . Three isolates (94-623, 90-1330, and AAH4) that produced BLIS in liquid broth were selected for further characterization . None of the inhibitory activities was related to the production of either organic acids or hydrogen peroxide . The BLIS produced by these strains were heat stable and proteinase K, pronase, and elastase sensitive but were trypsin and chymotrypsin resistant . They were stable at pH 2 and 12 and had molecular masses in the range of 14 to 30 kDa . Maximum production was observed during the mid-log phase . Following a curing procedure with novobiocin, only 90-1330 lost the ability to produce BLIS, suggesting that the BLIS might be plasmid encoded . Analysis of the inhibitory spectra revealed that the BLIS-producing strains also inhibited the growth of Actinobacillus minor, Actinobacillus porcinus, Enterococcus durans, Micrococcus luteus, Streptococcus agalactiae, Streptococcus dysgalactiae subsp . dysgalactiae, Streptococcus equi subsp . zooepidemicus, and S . dysgalactiae subsp . equisimilis . This study reports for the first time the ability of the swine pathogen S . suis serotype 2 to produce BLIS with the characteristics of classic bacteriocins . Further studies are required to investigate the possibility of using bacteriocin-producing strains to prevent swine infections caused by virulent strains of S . suis serotype 2 .
|
© 2005
Transgalactic Ltd (manufacturer of Bioscreen C software) |
Privacy Statement | P.O. Box
1393, 00101 Helsinki, Finland,
Last modified: May 25, 2005
| ||||||
