Identification of glycine betaine as a host-derived molecule required for the vegetative proliferation of the protozoan parasite Perkinsus olseni

Perkinsus olseni is an industrially significant protozoan parasite of Manila clam, Ruditapes philippinarum. So far, various media, based on Dulbecco's Modified Eagle Medium and Ham's F-12 nutrient mixture with supplementation of fetal bovine serum (FBS), have been developed to proliferate the parasitizing trophozoite stage of P. olseni. The present study showed that P. olseni did not proliferate in FBS-deficient Perkinsus broth medium (PBMΔF), but proliferated well in PBMΔF supplemented with tissue extract of host Manila clams, indicating that FBS and Manila clam tissue contained molecule(s) required for P. olseni proliferation. Preliminary characterization suggested that the host-derived molecule(s) was a heat-stable molecule(s) with a molecular weight of less than 3 kDa, and finally a single molecule required for the proliferation was purified by high-performance liquid chromatography processes. High-resolution electrospray ionization mass spectrometry and nuclear magnetic resonance analyses identified this molecule as glycine betaine (=trimethylglycine), and the requirement of this molecule for P. olsseni proliferation was confirmed by an assay using chemically synthesized, standard glycine betaine. Although glycine betaine was required for the proliferation of all examined Perkinsus species, supplementation of glycine betaine precursors, such as choline and betaine aldehyde, enhanced the proliferation of 4 Perkinsus species (P. marinus, P. chesapeaki, P. mediterraneus and P. honshuensis), but not of 2 others (P. olseni and P. beihaiensis). Thus, it was concluded that the ability to biosynthesise glycine betaine from its precursors varied among Perkinsus species, and that P. olseni and P. beihaiensis lack the ability required to biosynthesize glycine betaine for proliferation

Introduction for Fisheries and Aquatic Biology

Chapter I. Aquatic Environment. Ken FURUYA and Ichiro YASUDA : chapter_1.pdfChapter II. Biology and Ecology of Aqua-Shere. Toyoji KANEKO, Katsumi TSUKAMOTO, Atsushi TSUDA, Yuzuru SUZUKI and Katsufumi SATOH : chapter_2.pdfChapter III. Aquatic Resource and Production. Ichiro AOKI, Kazuo OGAWA, Taku YAMAKAWA and Tomoyoshi YOSHINAGA : chapter_3.pdfChapter IV. Chemistry of Aquatic Organism and Their Utilization. Hiroki ABE, Shugo WATABE, Yoshihiro OCHIAI, Shigeru OKADA, Naoko YOSHIKAWA, Yoshiharu KINOSHITA, Gen KANEKO and Shigeki MATSUNAGA : chapter_4.pdfChapter V. Relation between Aqua-Shere and Human Life. Hisashi KUROKURA, Hirohide MATSUSHIMA, Shingo KUROHAGI, Haruko YAMASHITA, Akinori HINO, Kazumasa IKUTA, Satoquo SEINO, Masahiko ARIJI, Ken FURUYA, Junichiro OKAMOTO and Nobuyuki YAGI : chapter_5.pdfPart of "Introduction for Fisheries and Aquatic Biology

A preliminary study on the infection of anisakid larvae in juvenile greater amberjack Seriola dumerili imported from China to Japan as mariculture seedlings

Juvenile greater amberjack Seriola dumerili (fork length: 39.5-43.0 cm) imported from China to Japan as mariculture seedlings were found infected with larval anisakid nematodes in the spring of 2005. The parasite was morphologically identified as Anisakis type I larva causing human anisakiasis. Based on the nucleotide sequence of ITS1-5.8S rRNA-ITS2 region, the parasite was tentatively identified as A. pegreffii, one of the species comprising A. simplex sensu lato. The main infection site was the wall and serous membrane of the stomach. No worms were found in the ventral side of the body muscle of fish. This is the first documented case of Anisakis infection in cultured marine fishes