Ko Yasumoto

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New aliphatic sulfates and sulfamates were isolated from Daphnia pulex as the Daphnia kairomones that induced morphological defense of a freshwater phytoplankton Scenedesmus gutwinskii var. heterospina (NIES-802). Their structures were determined by spectroscopic and synthetic studies.
4,8-Dimethylnonyl sulfate (1) and 3-methyl-4E-decenyl sulfate (2) were isolated from Daphnia pulex as the Daphnia kairomones that induced morphological defense of a freshwater phytoplankton Scenedesmus gutwinskii var. heterospina (NIES-802). The absolute configuration at C4 of 1 was determined by Ohrui's method applied to alcohol 3. The absolute(More)
2,6-Dimethylheptyl sulfate (1) and 6-methyloctyl sulfate (3) were isolated from Daphnia pulex as the Daphnia kairomones that induced morphological defense of a freshwater phytoplankton Scenedesmus gutwinskii var. heterospina (NIES-802). The absolute stereochemistry at C2 of 1 was determined by (1)H-NMR analysis of the (R)-MTPA ester of alcohol 2. The(More)
New brominated fatty acids (3, 5-8, 10) and new sterol esters (14-16) have been isolated from an unidentified marine sponge collected in Papua New Guinea. Their structures were determined on the basis of their spectroscopic data. A major component of the marine sponge (1) was tested for activities against Arutemia salina and some fungi.
Bacteria, including cyanobacteria, as well as some fungi, are known to deposit calcium carbonate (CaCO3) extracellularly in calcium-containing artificial medium. Despite extensive investigation, the mechanisms involved in extracellular formation of CaCO3 by bacteria have remained unclear. The ability of synthetic amines to remove carbon dioxide (CO2) from(More)
Little is known about the correlation between genotype and drug susceptibility in Mycobacterium avium (Mav) strains isolated from patients with Mav infections. To examine whether drug susceptibility profile of Mav is associated with genotype, we carried out variable-number tandem-repeat (VNTR) typing and drug susceptibility testing for Mav isolates from(More)
The brackish water clam Corbicula japonica inhabits rivers and brackish waters throughout Japan where the major fishing grounds in the Ibaraki Prefecture, Japan, are located at the Hinuma Lake and Hinuma River. Water salinity in the Lake Hinuma is low and stable due to the long distance from the Pacific Ocean, whereas that in the downstream of the river(More)
A new sulfoalkylresorcinol (1) was isolated from the marine-derived fungus, Zygosporium sp. KNC52. The structure of 1 was elucidated by spectroscopic methods including MS and NMR, and the absolute stereochemistry was determined by the modified Mosher's method. Compound 1 inhibited FtsZ polymerization in vitro and exhibited weak antimicrobial activity(More)
Most reef-building corals in tropical and subtropical areas symbiose with microalgae from the genus Symbiodinium (dinoflagellate) and depend on the photosynthate produced by the microalgae. The majority of corals acquire Symbiodinium from the surrounding environment through horizontal transfer, but the molecular mechanisms involved in the acquisition of(More)
TB, especially multidrug-resistant TB and extensively drug-resistant TB, is an important global health concern, and the novel development of effective anti-tuberculous drugs is urgently needed. Newly elucidated, critical information on the entire genome of Mycobacterium tuberculosis (MTB) and advances in knowledge regarding various mycobacterial virulence(More)