Angiogenic activity of osteopontin-derived peptide SVVYGLR

Angiogenesis plays an important role in various pathological conditions as well as some physiological processes. Although a number of soluble angiogenic factors have been reported, extracellular matrix also has crucial effect on angiogenesis through interaction with endothelial cells. Since recent reports showed osteopontin had some angiogenic activity, the effect of the SVVYGLR peptide, novel binding motif in osteopontin molecule, on angiogenesis was examined in this study. Synthetic peptide SVVYGLR did not have proliferative effect on endothelial cells but adhesion and migration activity to endothelial cells. Furthermore, SVVYGLR had as potent activity for tube formation in three-dimensional collagen gel as vascular endothelial growth factor which is known to be the strongest angiogenic factor. Electron microscopical analysis showed a number of microvilli on the endothelial luminar surface and tight junction formation in the luminar intercellular border between endothelial cells, indicating SVVYGLR induced cell porarity and differentiation of endothelial cells. This small peptide might be expected to stimulate angiogenesis to improve some ischemic conditions in the future because of some advantages due to smaller molecular weight.     

Synthesis and activity of pyrimidinylpropenamide antibiotics: the alkyl analogues of sparsomycin

Facile syntheses of sparsomycin (3) and its four analogues (4-7) based on diastereoselective oxidation of sulfide, sulfenylation, and coupling of 6-methyluracylacryllic acid with monooxodithioacetal amine, are described. Studies on the biological activity of morphological reversion on src(ts)-NRK cells were also carried out.     

Metabolism of deuterium-labeled jasmonic acid and OPC 8:0 in the potato plant (Solanum tuberosum L.)

The metabolism of deuterium-labeled (+/-)-jasmonicacid and 3-oxo-2-[(Z)pent-2'-enyl]-cyclopentan-1- octanoic acid in potato (Solanum tuberosum L.) was examined by using cultures of potato single-node stems. Deuterium-labeled (+/-)-jasmonic acid and 3-oxo-2-[(Z) pent-2'-enyl]cyclopentan-1-octanoic acid, which had been prepared from commercially available methyl (+/-)-jasmonate, were fed to the cultures, and the metabolites were extracted from the plants and analyzed by a liquid chromatography-selected ion monitoring system. The metabolism of deuterium-labeled (+/-)-jasmonic acid and 3-oxo-2-[(Z)-2'-pentenyl]cyclopentan-1-octanoic acid to 5' and 4'-O-glucopyranosyloxyjasmoic acids was strongly suggested.     

Nucleotide sequences of genes encoding allosamidin-sensitive and -insensitive chitinases produced by allosamidin-producing Streptomyces

Allosamidin is a strong inhibitor of family 18 chitinases. We previously reported the presence of allosamidin-sensitive and -insensitive chitinases (chitinase S and IS) in the culture filtrate of the allosamidin-producing strain, Streptomyces sp. AJ9463. In this study, we cloned and sequenced the genes encoding the two chitinases, which clarified that chitinase S and IS belong to the family 18 and 19 chitinase, respectively.     

Isolation and identification of sodium 2-propenyl thiosulfate from boiled garlic (Allium sativum) that oxidizes canine erythrocytes

Sodium 2-propenyl thiosulfate was identified in boiled garlic (Allium sativum). When canine erythrocytes were incubated with sodium 2-propenyl thiosulfate, the methemoglobin concentration and Heinz body percentage in erythrocytes were both increased, indicating that the compound induced oxidative damage in canine erythrocytes. It seems that this compound is one of the causative agents of garlic-induced hemolysis in dogs.     

Low temperature promotes annexin V expression in newt testis

We examined the effect of low temperatures on annexin V expression in newt testis. When newts were transferred to a low temperature (12 degrees C), up-regulation of annexin V protein was observed in secondary spermatogonia. In primary spermatocytes, high levels of annexin V expression were observed at both 12 degrees C and 22 degrees C, but at 12 degrees C the protein was localized in part of the cytoplasm of primary spermatocytes. These results indicate that in newt testis annexin V is a cold-sensitive protein, suggesting the possibility that annexin V might have a cold stress-related function in newt germ cells.     

NKT cells in the rat: organ-specific distribution of NK T cells expressing distinct V alpha 14 chains

Rat invariant TCR alpha-chains and NKT cells were investigated to clarify whether CD1d-mediated recognition by NKT cells is conserved further in evolution. Rats had multiple-copies of TRAV14 genes, which can be categorized into two types according to the diversity accumulated in the CDR2 region. Rats retained invariant TCR alpha forms with the homogeneous junctional region similar to mouse invariant TRAV14-J281. The proportion of invariant TCR among V alpha 14+ clones was 12.9% in the thymus and increased in the periphery, 31% in the spleen and 95% in hepatic sinusoidal cells. The invariant TRAV14-J281 was expressed by liver sinusoidal and splenic NKT cells with CD8, CD44high, and TCR V beta 8. Type 1 invariant TCR alpha was expressed more frequently in hepatic lymphocytes, while type 2 invariant TCR alpha was expressed predominantly in the spleen. Both types of cells cytolyzed to and were stimulated to proliferate by CD1d-expressing cells in a CD1d-restricted manner. These results suggested that rat NKT cells bearing distinct V alpha 14 chains are distributed in a tissue-specific pattern. NKT cell populations in rats were more variable than those in mice, indicating that they play novel roles in nature. The implication of the molecular interaction between the structurally diverse invariant TCR alpha and CD1d/ligand complex in different organs is discussed.     

Structural basis for the higher Ca(2+)-activation of the regulated actin-activated myosin ATPase observed with Dictyostelium/Tetrahymena actin chimeras

Replacement of residues 228-230 or 228-232 of subdomain 4 in Dictyostelium actin with the corresponding Tetrahymena sequence (QTA to KAY replacement: half chimera-1; QTAAS to KAYKE replacement: full chimera) leads to a higher Ca(2+)-activation of the regulated acto-myosin subfragment-1 ATPase activity. The ratio of ATPase activation in the presence of tropomyosin-troponin and Ca(2+) to that without tropomyosin-troponin becomes about four times as large as the ratio for the wild-type actin. To understand the structural basis of this higher Ca(2+)-activation, we have determined the crystal structures of the 1:1 complex of Dictyostelium mutant actins (half chimera-1 and full chimera) with gelsolin segment-1 to 2.0 A and 2.4 A resolution, respectively, together with the structure of wild-type actin as a control. Although there were local changes on the surface of the subdomain 4 and the phenolic side-chain of Tyr230 displaced the side-chain of Leu236 from a non-polar pocket to a more solvent-accessible position, the structures of the actin chimeras showed that the mutations in the 228-232 region did not introduce large changes in the overall actin structure. This suggests that residues near position 230 formed part of the tropomyosin binding site on actin in actively contracting muscle. The higher Ca(2+)-activation observed with A230Y-containing mutants can be understood in terms of a three-state model for thin filament regulation in which, in the presence of both Ca(2+) and myosin heads, the local changes of actin generated by the mutation (especially its phenolic side-chain) facilitate the transition of thin filaments from a "closed" state to an "open" state. Between 394 and 469 water molecules were identified in the different structures and it was found that actin recognizes hydrated forms of the adenine base and the Ca ion in the nucleotide binding site.