title: Preparation of (13)C-labeled ceramide by acetic acid bacteria and its incorporation in mice.
abstract: We prepared 2-hydroxypalmitoyl-sphinganine (dihydroceramide) labeled with a stable isotope by culturing acetic acid bacteria with (13)C-labeled acetic acid. The GC/MS spectrum of the trimethylsilyl derivative of (13)C-labeled dihydroceramide gave molecular ions with an increased mass of 12-17 Da over that of nonlabeled dihydroceramide. The fragment ions derived from both sphinganine base and 2-hydroxypalmitate were confirmed to be labeled with the stable isotope in the spectrum. Therefore, (13)C-labeled dihydroceramide can be an extremely useful tool for analyzing sphingolipid metabolism. The purified [(13)C]dihydroceramide was administered orally to mice for 12 days, and the total sphingoid base fractions in various tissues were analyzed by GC/MS. The spectrum patterns specific to (13)C-labeled sphingoids were detected in the tissues tested. Sphinganine pools in skin epidermis, liver, skeletal muscle, and synapse membrane in brain were replaced by [(13)C]sphinganine at about 4.5, 4.0, 1.0, and 0.3%, respectively. Moreover, about 1.0% of the sphingosine pool in the liver was replaced by [(13)C]sphingosine, implying that exogenous dihydroceramide can be converted to sphingosine. These results clearly indicate that ingested dihydroceramide can be incorporated into various tissues, including brain, and metabolized to other sphingolipids.
authors.affiliation: Central Research Institute, Mizkan Group Corporation, Handa, Aichi, Japan. h-fukami@mizkan.co.jp
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Fukami
authors.forename: Hideki
authors.initials: H
authors.lastname: Tachimoto
authors.forename: Mikiya
authors.initials: M
authors.lastname: Kishi
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kaga
authors.forename: Hatsue
authors.initials: H
authors.lastname: Waki
authors.forename: Machiko
authors.initials: M
authors.lastname: Iwamoto
authors.forename: Yasukazu
authors.initials: Y
authors.lastname: Tanaka
mesh_terms: D019342:Acetic Acid / Q000378:metabolism*; D000091:Acetobacter / Q000378:metabolism*; D000284:Administration, Oral; D000818:Animals; D002247:Carbon Isotopes; D002518:Ceramides / Q000008:administration & dosage / Q000096:biosynthesis* / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D007553:Isotope Labeling; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL
chemical_list: D002247:Carbon Isotopes; D002518:Ceramides; C109343:dihydroceramide; D019342:Acetic Acid