Kazuo Shin-ya

Spiruchostatins A and B, novel gene expression-enhancing substances produced by Pseudomonas sp.

Abstract Spiruchostatins A and B were isolated from Pseudomonas sp. as gene expression-enhancing substances. They possess novel bicyclic depsipeptides involving 4-amino-3-hydroxy-5-methylhexanoic acid and 4-amino-3-hydroxy-5-methylheptanoic acid residues, respectively, as shown in Fig. 1 Download high-res image (1KB) Download full-size image Figure 1 . Structures of spiruchostatins A ( 1 ) and B ( 2 ). .

Versipelostatin, a novel GRP78/Bip molecular chaperone down-regulator of microbial origin

Abstract We discovered a novel down-regulator of grp 78 gene expression designated as versipelostatin from the culture broth of Streptomyces versipellis 4083-SVS6. Its structure was determined to be a macrocyclic compound consisting of an α-acyltetronic acid and sugar moieties.

Absolute configuration of a novel glutamate receptor antagonist kaitocephalin

Abstract The absolute configuration of kaitocephalin, a novel glutamate antagonist, was determined by NMR spectral analysis of a cyclic derivative of kaitocephalin and by the modified Moshers method to be 2 S ,3 S ,4 R ,7 R and 9 S .

Synthesis of the proposed structure and revision of stereochemistry of kaitocephalin

A stereoselective total synthesis of the proposed structure of kaitocephalin (1) was accomplished starting from l-proline and d- and l-serines. However, its 1H NMR spectral data and retention time on HPLC were not identical with those of authentic natural kaitocephalin. The revised stereochemistry of natural kaitocephalin, (2R)-isomer (16), was inferred from further experiments employing diastereomers and model compounds.

Gymnasterol, a new antitumor steroid against IGF-dependent cells from Gymnascella dankaliensis

Abstract A new antitumor substance, gymnasterol ( 1 ), was isolated from the culture broth of Gymnascella dankaliensis . The structure of 1 was determined to be a novel ergostane steroid on the basis of NMR studies. Gymnasterol selectively inhibited IGF-1-dependent growth of MCF-7 human breast cancer cells.

Time courses of increased expression of signaling transduction molecules induced by basic fibroblast growth factor in PC12 cells

Abstract We previously demonstrated that basic fibroblast growth factor (bFGF) protected neuronal injury in in vivo experimental cerebral ischemia. The precise molecular mechanisms of the neuroprotective effect of bFGF, however, remains unsolved. We investigated time courses of up-regulated molecules involved in intracellular signaling transduction pathways induced by bFGF in PC12 cells to explore the possible neuroprotective mechanism of bFGF action. In Western blot analysis, bFGF increased expression of Ras mainly in the early stage up to 24 h, returning to the baseline level at 48 h. Expression of phosphatidylinositol 3-kinase (PI 3-kinase) was enhanced throughout the early and later stages, and was more up-regulated at 48 h compared to 24 h. The present findings suggest that bFGF might promote cell survival or proliferation mainly via Ras, and PI 3-kinase might be involved in cell survival and differentiation in PC12 cells.