Coordination behavior of amine bases to the axial site of a (dibenzo[b,i][1,4,8,11]tetraazacyclotetradecinato)cobalt(II)

The mutual interaction of various amine bases with the (dibenzo[b,i][1,4,8,11] tetraazacyclotetradecinato)cobalt(II) (Co(II)-1) was investigated by measuring electronic spectra in methyl benzoate. The Co(II)-1 became the pentacoordinated complex by taking up an amine base in the axile site: Co(II)-1 + B ? BCo(II)-1. For the mutual interaction of substituted pyridines with the Co(II)-1, the general behavior of the equilibrium constants was explained on the basis of the amine basicity and the Hammett equation by reference to the corresponding behavior of the porphyrin, corrin and corrole complexes. Moreover, there exists a systematic correlation between log K and the chemical shift of the corresponding 4-position in the ¹³C-NMR spectra of substituted pyridines. The isoequilibrium temperature obtained from a plot of ΔH against ΔS was 260 K. The equilibrium is primarily controlled by entropy at the usual temperature. The weaker coordination tendency of some hindered pyridine such as 2-methyl- and 2,6-dimethylpyridine toward Co(II)-1 was attributed to the steric effect between the in-plane ligand of Co(II)-1 and the 2- and/or 6-methyl groups of substituted pyridines in the coordination process.     

Triterpenes from periandra dulcis roots

Two new triterpenes from the root of Periandra dulcis were found to be 3,25-dioxoolean-12(13)-en-30-oic acid and 3,25-dioxoolean-18(19)-en-30-oic acid.     

Three new secoiridoid glucosides from Eustoma russellianum

Three new secoiridoid glucosides, eustomoside, eustoside and eustomorusside, have been isolated along with three known glucosides, sweroside, swertiamarin and gentiopicroside, as well as one unknown glycoside from Eustoma russellianum.     

No regional differences of cytochrome P450 expression in the liver of Cynomolgus monkeys (Macaca fascicularis).

Non-human primates are frequently used in toxicological studies the result of which are extrapolated to humans, but background data on drug metabolism ability among monkeys derived from different countries has not been published, especially on the key enzyme, cytochrome P450 (CYP450). We assessed the amounts of hepatic CYP450 obtained from cynomolgus monkeys of different ages and from different countries in this study. There were no regional differences of total P450 content, as well as major CYP450 isozymes (CYP 1A, 2A, 2B, 2C, 2D, 2E1 and 3A4) in cynomolgus monkeys by westernblot analysis. Similarly, there were no significant differences with hybrid cynomolgus monkeys, but variations in individual values were large. As for aging, total P450 contents declined in old cynomolgus monkeys (12-32 years of age). These results indicate the usefulness of basic data of hepatic CYP450 obtained from cynomolgus monkeys of different ages and from different countries.     

Isoform-Specific Redistribution of Calcineurin Aα and Aβ in the Hippocampal CA1 Region of Gerbils After Transient Ischemia

Abstract: To investigate isoform-specific roles of Ca²⁺/calmodulin-dependent phosphatase [calcineurin (CaN)] in ischemia-induced cell death, we raised antibodies specific to CaN Aα and CaN Aβ and localized the CaN isoforms in the hippocampal CA1 region of Mongolian gerbils subjected to a 5-min occlusion of carotid arteries. In the nonischemic gerbil, immunoreactions of both isoforms were highly enriched in CA1 regions, especially in the cytoplasm and apical dendrites of CA1 pyramidal neurons. At 4–7 days after the induced ischemia, immunoreactivities of the CaN Aα isoform in CA1 pyramidal cells were markedly reduced, whereas they were enhanced in the CA1 radiatum and oriens layers. In contrast, CaN Aβ immunoreactivities were reduced in all layers of the ischemic CA1 region, whereas they were enhanced in activated astrocytes, colocalizing with glial fibrillary acidic protein. These findings suggest that up-regulation of CaN Aα in afferent fibers in CA1 and up-regulation of CaN Aβ in reactive astrocytes may be involved in neuronal reorganization after ischemic injury.     

Suppression of electrophoretic anomaly of bent DNA segments by the structural property that causes rapid migration.

Intrinsic DNA curvature is speculated to be a common feature of all satellite DNA sequences and may aid in the tight winding of DNA in constitutive heterochromatin. Several satellite DNAs, however, show unusually rapid migration in non-denaturing polyacrylamide gels, which is just the opposite behavior of that shown by curved DNA structures. Employing bovine satellite I DNA monomer, we attempted to understand the molecular mechanism of 'rapid migration'. The phenomenon of rapid migration was temperature-dependent and to a small extent polyacrylamide-concentration-dependent. Physiological or near-physiological concentrations of Mg2+and Ca2+ions bent the rapid migrating DNA segment. Predominance of purine-purine base stacking over purine-pyrimidine in nucleotide sequence was strongly indicated to be the cause of the rapid migration. Furthermore, they seemed to be implicated in the formation of induced DNA bend. We also found that the satellite I monomer contains an intrinsic DNA curvature as do many other satellites. Heretofore, the rapid migration property has concealed the presence of curvature.     

Appendage Development in Clostridium bifermentans

The appendages of Clostridium bifermentans UK-A 1003 spores were shown to originate from a substance located just exterior to the outer forespore membrane. The dense spore coat develops along the periphery of this material, and, as the appendages develop in the cytoplasm, the coalescing spore coat intervenes between the appendages and their origin. Freeze etching revealed that the appendages are in the form of distinct fibers in proximity to the mature spore body. These fibers form a network around the spore, seemingly encasing it and insuring that the appendages remain attached to the mature, free spore. The inner wall of each appendage tubule is lined with fibers whereas the outer surface is smooth. The developing exosporium contained several layers consisting of small (3 nm) globular subunits; the outer exosporial surface is composed of relatively unstructured material.