Hirofumi Shimomura

Learn More
Resact, a peptide obtained from eggs, causes a change in the Mr, and a loss of 32P from a plasma membrane protein identified as guanylate cyclase. Here, a resact analog (125I-[Tyr1, Ser8] resact) was synthesized and shown to bind to isolated sperm membranes. Resact, but not speract, competed with the radiolabeled ligand for binding. When membranes were(More)
Pituitary adenylate cyclase activating polypeptide (PACAP) was isolated from ovine hypothalami and found to exist as two amidated forms with 38 (PACAP 38) and 27 (PACAP 27) residues. The amino acid sequences of PACAPs isolated from the vertebrates, such as a bird, a frog and teleost fish, appear to be well conserved. In the present study, we attempted to(More)
Lipopolysaccharide (LPS) of Burkholderia cepacia was purified by the conventional phenol-water extraction method (preparation BcLPS-1), followed by enzymatic treatments with DNase, RNase, trypsin, and proteinase K (preparation BcLPS-2), and finally by deoxycholate-phenol-water extraction (preparation BcLPS-3). Cells of LPS-hyporesponsive C3H/HeJ mice were(More)
Helicobacter pylori, a pathogen responsible for gastric and duodenal diseases, absorbs various steroid compounds into the cell membrane even though some are toxic to this bacterium. An earlier study by our group has demonstrated that progesterone is bactericidal to H. pylori. In this study, we newly synthesized a steroid compound, 17α-hydroxyprogesterone(More)
We have demonstrated that lipopolysaccharide (LPS) obtained from Burkholderia cepacia, an important opportunistic pathogen, has unique characteristics in both structure and activity. One of the structural characteristics is that the B. cepacia LPS has 4-amino-4-deoxy-L-arabinose (Ara4N) in its inner core region. Polymyxin B (PmxB) is known to act as an LPS(More)
The catabolic pathway for flavodoxin has yet to be clarified for any bacterial species. In this study, we found that the flavin mononucleotide in the flavodoxin of Helicobacter pylori is degraded to riboflavin via the phosphomonoesterase activity of class C acid phosphatase. The result is a conversion of holoflavodoxin to apoflavodoxin.
Two peptides associated with the eggs of the sea urchin, Lytechinus pictus, which stimulate L. pictus but not Arbacia punctulata sperm respiration rates, were purified and their amino acid sequences determined. The peptides (Gly-Phe-Asp-Leu-Thr-Gly-Gly-Gly-Val-Gln and Phe-Asp-Leu-Thr-Gly-Gly-Gly-Val-Gln) were found to be structurally similar to the peptide,(More)
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(More)
This study demonstrated that the vitamin D₃ decomposition product VDP1 exerts an antibacterial action against Helicobacter pylori but not against other bacteria. Treatment with VDP1 induced a collapse of cell membrane structures of H. pylori and ultimately lysed the bacterial cells. A unique dimyristoyl phosphatidylethanolamine in the membrane lipid(More)
Helicobacter pylori assimilates various steroids as membrane lipid components, but it can also survive in the absence of steroids. It thus remains to be clarified as to why the organism relies on steroid physiologically. In this study, we have found that phosphatidylcholine carrying a linoleic acid molecule or arachidonic acid molecule has the potential to(More)
  • 1