Sayaka Kurasawa

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Fertilization results in cortical granule exocytosis, which is thought to be involved in modifications of the zona pellucida that constitute the zona pellucida block to polyspermy. A previous report demonstrated that a decrease in the number of Lens culinaris agglutinin-staining granules, which are likely to be cortical granules, occurred during in vivo(More)
Germinal vesicle (GV)-intact fully grown mouse oocytes do not undergo cortical granule (CG) exocytosis in response to A23187 treatment, whereas metaphase II (MII)-arrested eggs do. This differential response may reflect the development of the ability of the egg to undergo CG exocytosis, which is responsible for the biochemical modification of the(More)
The structure of bisucaberin, a new siderophore, was determined to be 1,12-dihydroxy-1,6,12,17-tetraazacyclodocosane-2,5,13,16-tetron e by spectroscopic analysis and X-ray crystallographic analysis. The molecule of bisucaberin consists of a cyclic dimer of 1-hydroxy-1,6-diazaundecane-2,5-dione moiety and is closely related to nocardamine, the trimer of the(More)
Alkyl, cycloalkyl, allyl, 4-pentenyl, and benzyl alpha-glycosides of maltose, cellobiose, and lactose were prepared (17-77% yield; alpha/beta=70/30-96/4) via a direct reaction of the free disaccharides with a binary AcBr-AcOH mixture, followed by glycosidation with alcohol using FeCl3 in MeNO2 or CH2Cl2, Zemplén deacetylation, and resolution of the anomeric(More)
Mouse eggs microinjected with physiological concentrations of inositol 1,4,5-trisphosphate (IP3) do not emit the second polar body, form a pronucleus, or display a fertilization-associated set of changes in the pattern of protein synthesis. IP3-injected eggs, however, display a conversion of the zona pellucida glycoprotein ZP2 to ZP2f. The effect is(More)
Screening of new insecticidal and acaricidal antibiotics was carried out with reference to anti-brine shrimp activity from actinomycete strains isolated from marine environments. Of 200 actinomycete isolates, one isolate was found to produce a new substance, altemicidin. The strain was isolated from sea mud collected at Gamo, Miyagi Prefecture, Japan, and(More)
Extracellular polysaccharides of marine bacteria were screened for their antitumor activity against sarcoma-180 solid tumor in mice. An active polysaccharide was purified and named marinactan. The producing microorganism has a typical marine bacterial nature requiring sea water for growth and was identified as Flavobacterium uliginosum. Marinactan is a(More)
Alteromonas haloplanktis strain SB-1123 isolated from deep-sea mud produced a new siderophore, bisucaberin. Bisucaberin rendered tumor cells susceptible to cytolysis mediated by murine peritoneal macrophages which were elicited by Proteose peptone and not yet activated by lymphokine. Bisucaberin exerted its sensitizing activity by both the preincubation(More)
Psi-tectorigenin, an isoflavonoid, was isolated from a culture filtrate of actinomycetes as an inhibitor of epidermal growth factor-induced phosphatidylinositol turnover in cultured A431 cells. It inhibited phosphatidylinositol turnover with an IC50 of about 1 microgram/ml; thus, its inhibitory activity was 6-times stronger than that of genistein or orobol.(More)