The SI strain of measles virus derived from a patient with subacute sclerosing panencephalitis possesses typical genome alterations and unique amino acid changes that modulate receptor specificity and reduce membrane fusion activity

Subacute sclerosing panencephalitis (SSPE) is a fatal sequela associated with measles and is caused by persistent infection of the brain with measles virus (MV). The SI strain was isolated in 1976 from a patient with SSPE and shows neurovirulence in animals. Genome nucleotide sequence analyses showed that the SI strain genome possesses typical genome alterations for SSPE-derived strains, namely, accumulated amino acid substitutions in the M protein and cytoplasmic tail truncation of the F protein. Through the establishment of an efficient reverse genetics system, a recombinant SI strain expressing a green fluorescent protein (rSI-AcGFP) was generated. The infection of various cell types with rSI-AcGFP was evaluated by fluorescence microscopy. rSI-AcGFP exhibited limited syncytium-forming activity and spread poorly in cells. Analyses using a recombinant MV possessing a chimeric genome between those of the SI strain and a wild-type MV strain indicated that the membrane-associated protein genes (M, F, and H) were responsible for the altered growth phenotype of the SI strain. Functional analyses of viral glycoproteins showed that the F protein of the SI strain exhibited reduced fusion activity because of an E300G substitution and that the H protein of the SI strain used CD46 efficiently but used the original MV receptors on immune and epithelial cells poorly because of L482F, S546G, and F555L substitutions. The data obtained in the present study provide a new platform for analyses of SSPE-derived strains as well as a clear example of an SSPE-derived strain that exhibits altered receptor specificity and limited fusion activity.     

Radical scavenging activity of dicaffeoyloxycyclohexanes: contribution of an intramolecular interaction of two caffeoyl residues

Six regio- and stereoisomers of dicaffeoyloxycyclohexanes and 2,4-di-O-caffeoyl-1,6-anhydro-beta-D-glucose were synthesized as model compounds of dicaffeoylquinic acids, and their radical scavenging activity was evaluated by DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt) radical scavenging tests. Both DPPH and ABTS radical scavenging reactions of these compounds consisted of two different steps. In the first step, catechol moieties of the caffeoyl residues were rapidly converted to o-quinone structures and no significant difference in the reactivity was observed among the tested compounds. In the second step, however, the rate of the reaction increased as the intramolecular distance of the two caffeoyl residues decreased. A novel intramolecular coupling product, which could scavenge additional radicals, was isolated from the reaction mixture of trans-1,2-dicaffeoyloxycyclohexane and DPPH radical. The result suggests that the second step of the radical scavenging reaction is arising from an intramolecular interaction between the two caffeoquinone residues to regenerate catechol structures, and that the closer their distance is, the more rapidly they react. The radical scavenging activity of natural dicaffeoylquinic acids in a biological aqueous system might also depend on the positions of caffeoyl ester groups.     

A repeating unit of the DYZ1 family on the human Y chromosome consists of segments with partial male-specificity

An average-sized human Y chromosome contains about 3,000 copies of the repeating DNA family DYZ1. A major repeating unit of the family, pHY10, has been cloned and an entire 3,564-bp sequence has already been determined by Nakahori et al. (1986). In the present study, pHY10 was divided into six consecutive segments, A to F, which were independently amplified by the PCR technique to see if they were strictly male-specific. pHY10 appears to consist of segments of various male-specificity. The B segment was apparently male-specific; however, the use of additional techniques (Southern-blot analysis or second PCR amplification in combination with the standard PCR) revealed homologous sequences in some females. None of the six segments of pHY10 may be male-specific in a strict sense. Different segments appear to be conserved during evolution to different extents. The 323-bp E segment appears to be the least conserved and to be responsible for the generation of most variations within the DYZ1 family.     

Rad50 is involved in MMS-induced recombination between homologous chromosomes in mitotic cells

The structural maintenance of chromosomes (SMC) family proteins (Smc1-Smc6) typically consist of two coiled-coil domains, an amino-terminal head domain, and a carboxyl-terminal tail domain. Rad50, a component of the Mre11/Rad50/Xrs2 (MRX) complex, has a similar domain structure to the SMC proteins. In Saccharomyces cerevisiae, the MRX complex appears to be essential for recombination between homologous chromosomes in meiotic cells, but not in cells undergoing vegetative growth. Here we provide for the first time evidence that Rad50, like Smc6, is required for the induction of recombination between homologous chromosomes in cells in the vegetative growth state upon exposure to methyl methanesulfonate. However, UV-induced recombination between homologous chromosomes is intact in both rad50 and smc6-56 mutant cells.     

The cDNA microarray analysis using an Arabidopsis pad3 mutant reveals the expression profiles and classification of genes induced by Alternaria brassicicola attack

The hypersensitive response (HR) was induced in a wild-type Arabidopsis thaliana plant (Columbia) (Col-wt) by inoculation with Alternaria brassicicola that causes the development of small brown necrotic lesions on the leaves. By contrast, pad3-1 mutants challenged with A. brassicicola produced spreading lesions. The cell death in pad3-1 mutants could not inhibit the pathogen growth and development, although both production of H(2)O(2) and localized cell death were similar in Col-wt and pad3-1 plants after the inoculation. The difference between Col-wt and pad3-1 plants is defense responses after the occurrence of cell death. In other words, PAD3 is necessary for defense response to A. brassicicola. Therefore, we examined the changes in the expression patterns of ca. 7,000 genes by cDNA microarray analysis after inoculation with A. brassicicola. The cDNA microarrays were also done to analyze Arabidopsis responses after treatment with signal molecules, reactive oxygen species (ROS)-inducing compounds and UV-C. The results suggested that the pad3-1 mutation altered not only the accumulation of camalexin but also the timing of expression of many defense-related genes in response to the challenge with A. brassicicola. Furthermore, the plants integrate two or more signals that act together for promoting the induction of multiple defense pathways.     

Synthesis and biological evaluation of pyrrolidine derivatives as novel and potent sodium channel blockers for the treatment of ischemic stroke

A novel series of pyrrolidine derivatives as Na⁺ channel blockers was synthesized and evaluated for their inhibitory effects on neuronal Na⁺ channels. Structure–activity relationship (SAR) studies of a pyrrolidine analogue 2 led to the discovery of 5e as a potent Na⁺ channel blocker with a low inhibitory action against human ether-a-go-go-related gene (hERG) channels. Compound 5e showed remarkably neuroprotective activity in a rat transient middle cerebral artery occlusion (MCAO) model, suggesting that 5e would act as a neuroprotectant for ischemic stroke.     

Neuronal interactions between neuropeptide W- and orexin- or melanin-concentrating hormone-containing neurons in the rat hypothalamus

Neuropeptide W (NPW) was recently discovered as the endogenous ligand for GPR7 and GPR8, which are orphan G protein-coupled receptors isolated from the porcine brain. These receptors are assumed to be involved in feeding regulation and/or energy homeostasis. Recent anatomical studies have revealed that high levels of GPR7 mRNA are distributed in the brain, including the hypothalamus and amygdala. However immunohistochemical studies on the distribution and localization of NPW have revealed differing results concerning whether or not NPW-containing cell bodies and their processes are present in the hypothalamus. Only a few immunohistochemical reports have been published concerning the presence of NPW-containing neurons in the brains of rodents, while there have been no anatomical studies of the co-localization of this neuropeptide with other transmitters. On this basis, we used a specific antiserum against NPW to determine immunohistochemically the presence of NPW-containing neurons in the rat hypothalamus. Many NPW-like immunoreactive cell bodies and their processes could be detected in the caudal region of the lateral hypothalamus but not in its anterior or middle regions. Given this positive identification of NPW-containing neurons in the lateral hypothalamus, we further studied the nature of interaction between NPW-containing neurons and neurons containing feeding regulating peptides such as orexin- and melanin-concentrating hormone (MCH). Very close interactions between NPW-containing nerve processes and orexin- and MCH-containing neuronal cell bodies and processes could be observed. These morphological findings strongly suggest that NPW is involved in the regulation of feeding and/or sleep/arousal behavior through orexin- and/or MCH-mediated neuronal pathways.