Tohoku University · Environmental Science
Professor Mari Yotsu-Yamashita's research lab specializes in marine natural products chemistry, with a primary focus on the isolation, structural elucidation, and biosynthetic investigation of potent marine toxins—particularly tetrodotoxin (TTX) and saxitoxin analogs—found in pufferfish, amphibians, and marine invertebrates. The lab employs advanced analytical techniques such as LC-MS, NMR spectroscopy, and radio-ligand binding assays to study toxin structure-activity relationships, receptor interactions, and biosynthetic pathways. A key research direction involves identifying novel toxin derivatives and their precursors to unravel the enzymatic mechanisms behind toxin production in marine organisms.
Figures are computed from collected data and may differ slightly.
Some species of puffer fish have been reported to possess both of tetrodotoxin and saxitoxin, which share one binding site on sodium channels. We purified a novel soluble glycoprotein that binds to these toxins from plasma of the puffer fish, Fugu pardalis, and named puffer fish saxitoxin and tetrodotoxin binding protein (PSTBP). PSTBP possessed a binding capacity of 10.6 +/- 0.97 nmol x mg(-1) protein and a K(d) of 14.6 +/- 0.33 nm for [(3)H]saxitoxin in equilibrium binding assays. [(3)H]Saxito
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolycavernoside A: a novel glycosidic macrolide from the red alga Polycavernosa tsudai (Gracilaria edulis)Mari Yotsu-Yamashita, Robert L. Haddock, and Takeshi YasumotoCite this: J. Am. Chem. Soc. 1993, 115, 3, 1147–1148Publication Date (Print):February 1, 1993Publication History Published online1 May 2002Published inissue 1 February 1993https://pubs.acs.org/doi/10.1021/ja00056a048https://doi.org/10.1021/ja00056a048research-articleACS PublicationsReques
Even though tetrodotoxin (TTX) is a widespread toxin in marine and terrestrial organisms, very little is known about the biosynthetic pathway used to produce it. By describing chemical structures of natural analogs of TTX, we can start to identify some of the precursors that might be important for TTX biosynthesis. In the present study, an analog of TTX, 5,11-dideoxyTTX, was identified for the first time in natural sources, the ovary of the pufferfish and the pharynx of a flatworm (planocerid sp
Bufonid anurans of the genus Atelopus contain both steroidal bufadienolides and various guanidinium alkaloids of the tetrodotoxin class. The former inhibit sodium-potassium ATPases, whereas the latter block voltage-dependent sodium channels. The structure of one guanidinium alkaloid, zetekitoxin AB, has remained a mystery for over 30 years. The structure of this alkaloid now has been investigated with a sample of approximately 0.3 mg, purified from extracts obtained decades ago from the Panamani
Tetrodotoxin (TTX) is well known as the puffer fish toxin. Naturally occurring analogs of TTX have been isolated from puffer fish, newts and frogs, and their structures have been determined by spectroscopic methods. Additionally, TTX analogs have been prepared by chemical modification to investigate its binding site on sodium channels and the structure-activity relationship of TTX. In this article, the NMR data of TTX analogs are listed, and the chemical modification methods for preparation of T
Tetrodotoxin (TTX) and its deoxy analogs, 5-deoxyTTX, 11-deoxyTTX, 6,11-dideoxyTTX, and 5,6,11-trideoxyTTX, were quantified in the tissues of three female and three male specimens of the marine puffer fish, Fugu niphobles, from the southern coast of Korea, and in the whole body of the brackishwater puffer fishes, Tetraodon nigroviridis (12 specimens) and Tetrodon biocellatus (three specimens) from Southeast Asia using LC/MS in single ion mode (SIM). Identification of these four deoxy analogs in
Identification of new tetrodotoxin (TTX) analogs from TTX-possessing animals might provide insight into its biosynthesis and metabolism. In this study, four new analogs, 8-epi-5,6,11-trideoxyTTX, 4,9-anhydro-8-epi-5,6,11-trideoxyTTX, 1-hydroxy-8-epi-5,6,11-trideoxyTTX, and 1-hydroxy-4,4a-anhydro-8-epi-5,6,11-trideoxyTTX, were isolated from the newt, Cynops ensicauda popei, and their structures were determined using spectroscopic methods. These are the first 8-epi-type analogs of TTX that have be
Two novel phlorotannins with a molecular weight of 974, temporarily named 974-A and 974-B, were isolated from the polyphenol powder prepared from the edible marine brown alga Ecklonia kurome Okamura, and their chemical structures were determined by spectroscopic method. The isolated yield of the total of 974-A and 974-B was approximately 4% (w/w) from the polyphenol powder. In 974-A, the carbon at the C2' position in the A ring of phlorofucofuroeckol-A forms a C-C bond with the carbon at the C2″
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