Construction of nitrogen-heterocyclic compounds through zirconium mediated intramolecular alkene-carbonyl coupling reaction of N-(o-alkenylaryl)carbamate derivatives

Intramolecular alkene-carbonyl coupling reaction of N-benzyl-N-(o-alkenylaryl)carbamate derivative derived from o-aminostyrene, o-(aminomethyl)styrene and o-aminoallylbenzene smoothly proceeded by treating with zirconocene-butene complex to give the corresponding lactam derivative.     

Origin of the vertebrate visual cycle: III. Distinct distribution of RPE65 and beta-carotene 15,15'-monooxygenase homologues in Ciona intestinalis

We previously identified three genes that encode putative visual cycle proteins that are homologues of retinal G-protein coupled receptor (Ci-opsin3), cellular retinaldehyde-binding protein (Ci-CRALBP) and beta-carotene 15,15'-monooxygenase (Ci-BCO) in the ascidian Ciona intestinalis. Ci-opsin3 and Ci-CRALBP are localized in both ocellus photoreceptor cells and surrounding non-photoreceptor cells in the brain vesicle of the larva. In the present study, we investigated the possible role and evolutionary origin of the BCO/RPE65 family in the visual cycle by analyzing Ci-BCO localization by immunohistochemistry and by identifying a novel gene that encodes a homologue of retinal pigment epithelium-specific 65 kDa protein (Ci-RPE65) in C. intestinalis. In situ hybridization and expressed sequence tag (EST) profiles consistently suggest that Ci-RPE65 is not significantly expressed in the ocellus and brain vesicle of the larva. Ci-RPE65 is expressed in the neural complex, a photoreceptor organ of the adult ascidian, at a level comparable to that of Ci-opsin3 and Ci-CRALBP. Ci-RPE65 is also expressed in various adult tissues, including the gill, body wall and intestine, suggesting that Ci-RPE65 plays a role in addition to that in the visual cycle. In contrast, Ci-BCO is predominantly localized in ocellus photoreceptor cells of the larva. The larval visual cycle seems to use Ci-opsin3 as a photo-isomerase. Our results also suggest that the RPE65-dependent visual cycle is used in the adult photoreceptors of a primitive chordate.     

Adsorption characteristics of bisphenol A onto carbonaceous materials produced from wood chips as organic waste

A single-chain amphiphile containing a rigid Schiff base segment, 3-cyano-N-benzylidene hexadecylamine (CNBHB) in the polar head group was synthesized and studied for its vesicle-forming properties. The dependence of the aggregation behavior of the vesicles as such and in the presence of manganese ions were studied as a function of temperature using differential scanning calorimetry and turbidity measurements. Transmission electron microscopy (TEM) was used to analyze the morphology of the vesicles, showed interesting features with fusion of regular structures, and were quite stable. In the presence of manganese ions, fusion of vesicles takes place. This could be due to the metal ions that are bound to the surface of the vesicles that cause a partial destruction of the hydration shell on the surface of the vesicles. The reduction in the hydration force could thus be responsible for the fusion.     

Phosphorescent Ruthenium Complexes with a Nitroimidazole Unit that Image Oxygen Fluctuation in Tumor Tissue

Understanding oxygen fluctuation in a cancerous tumor is important for effective treatment, especially during radiotherapy. In this paper, ruthenium complexes bearing a nitroimidazole group are shown to report the oxygen status in tumor tissue directly. The nitroimidazole group was known to be accumulated in hypoxic tumor tissues. On the other hand, the ruthenium complex showed strong phosphorescence around 600 nm. The emission of ruthenium is quenched instantaneously by molecular oxygen due to energy transfer between triplet states of oxygen and ruthenium complex, but the emission is then recovered by the removal of oxygen. Thus, we could observe oxygen fluctuation in tumor tissue in a real‐time manner by monitoring the phosphorescence of the ruthenium complex. The versatility of the probe is demonstrated by monitoring oxygen fluctuation in living cells and tumor tissue planted in mice. The ruthenium complex promptly penetrated plasma membrane and accumulated in cells to emit its oxygen‐dependent phosphorescence. In vivo experiments revealed that the oxygen level in tumor tissue seems to fluctuate at the sub‐minute timescale.     

Improved separation of alpha chains of collagen type I, type III, and type V by noninterrupted electrophoresis using thioglycolic acid as a negatively charged reducer

Improved separation of alpha chains of collagen type I (alpha 1 [I]2 alpha 2[I]), type III(alpha 1[III]3), and type V (alpha 1[V]alpha 3[V])was achieved by noninterrupted sodium dodecyl sulfate-polyacrylamide gel electrophoresis with a negatively charged reducer, thioglycolic acid. The thioglycolic acid, added to the running buffer of the cathodic reservoir, in the middle of electrophoresis quickly migrated in the gel anode, reducing interchain disulfide linkages in collagen type III and dissociating it into its alpha chain monomer, alpha 1[III], without an interruption of electrophoresis. The alpha chain, alpha 1[III], migrated more slowly than the alpha 1 [I] and alpha 2[I] chains of collagen type I, resulting in an excellent separation of alpha 1[III] from alpha 1[I]. The mobility of alpha 1[III] could be controlled by varying the time of thioglycolic acid addition to the running buffer. This enabled us not only to separate alpha 1[III] from alpha 1[I] and alpha 1[V], but also to precisely quantitate these alpha chains, even at low protein loading of mixed samples.     

DNA DAMAGE and ITS REPAIR IN Dictyostelium discoideum IRRADIATED BY HEALTH LAMP LIGHT (UV- B)

Irradiation by health lamp (HL) light (280–320 nm) more efficiently induced cell killing and mutation in a radiation sensitive mutant (TW8) of Dictyostelium discoideum as compared with the parental wild-type strain (NC4). This light as well as a germicidal lamp-light (254 nm) produced pyrimidine dimers. The dimers were removed from DNA molecules by excision repair in NC4, but more slowly in TW8. It is suggested that pyrimidine dimers are the main DNA damage caused by HL light in D. discoideum , and that this results in cell killing and induced mutation.     

Synthesis of poly (ether-sulfone-amide)s by palladium-catalyzed polycondensation of aromatic dibromides containing ether sulfone structure,aromatic diamines,and carbon monoxide

A general method for the preparation of aromatic poly (ether-sulfone-amide)s has been developed. Polymerization is based on the palladium-catalyzed polycondensation of aromatic dibromides containing ether sulfone structural units, aromatic diamines, and carbon monoxide. Reactions were carried out in N, N-dimethylacetamide (DMAc) in the presence of palladium catalyst, triphenylphosphine, and 1,8-diazabicyclo [5,4,0]–7–undecene (DBU), and gave a series of poly (ether-sulfone-amide)s with inherent viscosities up to 0.86 dL/g under mild conditions. The polymers were quite soluble in strong acids, dipolar aprotic solvents, and pyridine. Thermogravimetry of the polymers showed excellent thermal stability, indicating that 10% weight losses of the polymers were observed in the range above 470°C in air. The glass transition temperatures of the polymers were around 230°C, which are higher than those of poly (ether-sulfone) analogues. These polymers also showed the good tensile strengths and tensile modulus. © 1994 John Wiley & Sons, Inc.