ABSTRACT
This study demonstrated that the cells of Helicobacter felis and Helicobacter cinaedi spontaneously absorb cholesterol added to the medium. A recent study by our group has revealed that phosphatidylethanolamine (PtdEtn) of Helicobacter pylori contains myristic acid as the most predominant saturated fatty acid and that the PtdEtn of this bacterium binds cholesterol more selectively than cholesteryl ester. We, therefore, isolated the PtdEtn from the two Helicobacter species to analyze the hydrophobic interaction between cholesterol and its glycerophospholipid. PtdEtn of the Helicobacter bacteria interacted more selectively with cholesterol than with cholesteryl ester, and the degree of the selective binding of cholesterol was higher in the PtdEtn than in the phosphatidylglycerol-cardiolipin of the same bacteria. These results suggest the possibility that the cells of H. felis and H. cinaedi may contain abundant PtdEtn with myristic acid. On this basis, we analyzed the PtdEtn molecular species of the Helicobacter bacteria and demonstrated that the PtdEtn containing myristic acid accounts for more than 35% in the total PtdEtn. These results suggest that the myristoyl PtdEtn takes part in the absorption of cholesterol in H. felis and H. cinaedi.
Subject(s)
Cardiolipins/metabolism , Cholesterol Esters/metabolism , Cholesterol/metabolism , Helicobacter/metabolism , Phosphatidylethanolamines/metabolism , Phosphatidylglycerols/metabolism , Binding Sites , Cardiolipins/chemistry , Helicobacter/chemistry , Helicobacter felis/chemistry , Helicobacter felis/metabolism , Phosphatidylethanolamines/chemistry , Phosphatidylglycerols/chemistryABSTRACT
"Helicobacter (H.) heilmannii" type 1 colonizes the human stomach. It has been shown to be identical to "Candidatus H. suis", a Helicobacter species colonizing the stomach of more than 60% of slaughter pigs. This bacterium is, until now, not isolated in vitro. The effect of vaccination on "Candidatus H. suis" infection was studied in a mouse model. Mice were vaccinated intranasally or subcutaneously with whole bacterial cell lysate of Helicobacter pylori or Helicobacter felis and subsequently challenge infected with "Candidatus H. suis". Intranasal and subcutaneous immunisation caused a decrease in faecal excretion of "Candidatus H. suis" DNA. Urease tests on stomach tissue samples at 16 weeks after challenge infection were negative in all H. felis intranasally immunized animals and in the majority of the animals of the other immunisation groups. Since PCR on stomach tissue samples at 16 weeks after challenge infection could still detect "Candidatus H. suis DNA" in all immunisation-challenge groups, complete clearance of challenge bacteria was not achieved.
