Morphine-Induced Changes in Histamine Dynamics in Mouse Brain

The effect of the acute morphine treatment on histamine (HA) pools in the brain and the spinal cord was examined in mice. Morphine (1-50 mg/kg, s.c.) administered alone caused no significant change in the steady-state levels of HA and its major metabolite, tele-methylhistamine (t-MH), in the brain. However, depending on the doses tested, morphine significantly enhanced the pargyline (65 mg/kg, i.p.)-induced accumulation of t-MH and this effect was antagonized by naloxone. A specific inhibitor of histidine decarboxylase, alpha-fluoromethylhistidine (alpha-FMH) (50 mg/kg, i.p.), decreased the brain HA level in consequence of the almost complete depletion of the HA pool with a rapid turnover. Morphine further decreased the brain HA level in alpha-FMH-pretreated mice. Morphine administered alone significantly reduced the HA level in the spinal cord, an area where the turnover of HA is very slow. These results suggest that the acute morphine treatment increases the turnover of neuronal HA via opioid receptors, and this opiate also releases HA from a slowly turning over pool(s).     

Effects of the Histamine H3-Agonist (R)-α-Methylhistamine and the Antagonist Thioperamide on Histamine Metabolism in the Mouse and Rat Brain

To study the feedback control by histamine (HA) H3-receptors on the synthesis and release of HA at nerve endings in the brain, the effects of a potent and selective H3-agonist, (R)-alpha-methylhistamine, and an H3-antagonist, thioperamide, on the pargyline-induced accumulation of tele-methylhistamine (t-MH) in the brain of mice and rats were examined in vivo. (R)-alpha-Methylhistamine dihydrochloride (6.3 mg free base/kg, i.p.) and thioperamide (2 mg/kg, i.p.), respectively, significantly decreased and increased the steady-state t-MH level in the mouse brain, whereas these compounds produced no significant changes in the HA level. When administered to mice immediately after pargyline (65 mg/kg, i.p.), (R)-alpha-methylhistamine (3.2 mg/kg, i.p.) inhibited the pargyline-induced increase in the t-MH level almost completely during the first 2 h after treatment. Thioperamide (2 mg/kg, i.p.) enhanced the pargyline-induced t-MH accumulation by approximately 70% 1 and 2 h after treatment. Lower doses of (R)-alpha-methylhistamine (1.3 mg/kg) and thioperamide (1 mg/kg) induced significant changes in the pargyline-induced t-MH accumulation in the mouse brain. In the rat, (R)-alpha-methylhistamine (3.2 mg/kg, i.p.) and thioperamide (2 mg/kg, i.p.) also affected the pargyline-induced t-MH accumulation in eight brain regions and the effects were especially marked in the cerebral cortex and amygdala. These results indicate that these compounds have potent effects on HA turnover in vivo in the brain.     

Genetic structure and differentiation of the Japanese extremely long-tailed chicken breed (Onagadori), associated with plumage colour variation: suggestions for its management and conservation

The Onagadori is a distinguished chicken breed that is characterized by an extremely long tail in the male. In this breed, three different plumage colour varieties have been developed (black-breasted white, black-breasted red and white) in which the black-breasted white is believed to be the original colour of the Onagadori, based on historical records. To establish a conservation strategy, 176 birds were genotyped for autosomal microsatellites. Significant genetic distinctness was found between the original (black-breasted white) and two derivative varieties ( F _ST = 0.091 and 0.093). At the same time, a Bayesian model-based clustering revealed that the majority of individuals belonging to the black-breasted red and white varieties had an extremely low proportion of the genome shared with the original type (black-breasted white). This suggests that derivative varieties were created by crossing with other breeds, with low introgression of the original-type genome. We propose that the three plumage colour varieties should be treated as separate genetic units in a conservation programme.     

Binding of a pleurotolysin ortholog from Pleurotus eryngii to sphingomyelin and cholesterol-rich membrane domains

A mixture of sphingomyelin (SM) and cholesterol (Chol) exhibits a characteristic lipid raft domain of the cell membranes that provides a platform to which various signal molecules as well as virus and bacterial proteins are recruited. Several proteins capable of specifically binding either SM or Chol have been reported. However, proteins that selectively bind to SM/Chol mixtures are less well characterized. In our screening for proteins specifically binding to SM/Chol liposomes, we identified a novel ortholog of Pleurotus ostreatus, pleurotolysin (Ply)A, from the extract of edible mushroom Pleurotus eryngii, named PlyA2. Enhanced green fluorescent protein (EGFP)-conjugated PlyA2 bound to SM/Chol but not to phosphatidylcholine/Chol liposomes. Cell surface labeling of PlyA2-EGFP was abolished after sphingomyelinase as well as methyl-β-cyclodextrin treatment, removing SM and Chol, respectively, indicating that PlyA2-EGFP specifically binds cell surface SM/Chol rafts. Tryptophan to alanine point mutation of PlyA2 revealed the importance of C-terminal tryptophan residues for SM/Chol binding. Our results indicate that PlyA2-EGFP is a novel protein probe to label SM/Chol lipid domains both in cell and model membranes.     

Isolation and characterization of a novel mycovirus infecting an edible mushroom,Grifola frondosa

Grifola frondosa (Maitake mushroom) is an important cultivated mushroom due to its medicinal and nutrient values. In this study, we isolated and characterized a novel partitivirus (named Grifola frondosa partitivirus 1, GfPV1) infecting a standard G. frondosa strain Gf-N2. This virus has a two-segmented dsRNA genome (dsRNA1 and dsRNA2) with nucleotide lengths of 2.3 and 2.2 kbp, respectively. The coding strand of dsRNA1 and dsRNA2 segments carries single open reading frame encoding RNA-dependent RNA polymerase (RdRp) and a coat protein (CP), respectively. BLAST searches and phylogenetic analyses showed that GfPV1 is most closely related to a betapartitivirus, Lentinula edodes partitivirus 1 (RdRp <70% and CP <60% amino acid sequence identities), but the sequence divergence suggests that GfPV1 is classifiable as a new member of the genus Betapartitivirus, family Partitiviridae. The presence of GfPV1 does not affect colony morphology and fruiting body development of G. frondosa. This is the first report investigating the effects of a mycovirus infection on the colony morphology and fruiting body development of G. frondosa. Interestingly, GfPV1 accumulations markedly decreased along with the fruiting body maturation stages, suggesting the inhibition of virus multiplication during sexual phase of the G. frondosa life cycle.     

Genetic polymorphisms and antiviral activity in the bovine MX1 gene

Bovine MX1 cDNAs consisting of 2280 bp from 11 animals of five breeds and from a cultured cell line were sequenced and compared with previously reported data. Ten nucleotide substitutions were synonymous mutations, and a single nucleotide substitution at 458 resulted in an amino acid exchange of Ile (ATT) and Met (ATG). A 13-bp deletion-insertion mutation was also found in the 3'-UTR. Based on the nucleotide substitutions found in this study, bovine MX1 cDNA was classified into 11 genotypes. A phylogenetic tree of the 11 genotypes suggested that the genotypes observed in Brahman were a great genetic distance from other genotypes. An 18-bp deletion-insertion variation at position 171 was found to be the result of alternative splicing. The 18-bp deletion-insertion is located at the boundary between exon 3 and intron 3. Permanently transfected 3T3 cell lines expressing bovine MX1 mRNA were established to analyse the antiviral potential against VSVDeltaG*-G infection. Transfected cell clones expressing bovine MX1 mRNA showed a significantly smaller number of cells infected with VSVDeltaG*-G compared with the control cells. These results indicate that the bovine MX1 protein has potent antiviral activity.     

Karyotypic evolution in the Galliformes: an examination of the process of karyotypic evolution by comparison of the molecular cytogenetic findings with the molecular phylogeny

To define the process of karyotypic evolution in the Galliformes on a molecular basis, we conducted genome-wide comparative chromosome painting for eight species, i.e. silver pheasant (Lophura nycthemera), Lady Amherst's pheasant (Chrysolophus amherstiae), ring-necked pheasant (Phasianus colchicus), turkey (Meleagris gallopavo), Western capercaillie (Tetrao urogallus), Chinese bamboo-partridge (Bambusicola thoracica) and common peafowl (Pavo cristatus) of the Phasianidae, and plain chachalaca (Ortalis vetula) of the Cracidae, with chicken DNA probes of chromosomes 1-9 and Z. Including our previous data from five other species, chicken (Gallus gallus), Japanese quail (Coturnix japonica) and blue-breasted quail (Coturnix chinensis) of the Phasianidae, guinea fowl (Numida meleagris) of the Numididae and California quail (Callipepla californica) of the Odontophoridae, we represented the evolutionary changes of karyotypes in the 13 species of the Galliformes. In addition, we compared the cytogenetic data with the molecular phylogeny of the 13 species constructed with the nucleotide sequences of the mitochondrial cytochrome b gene, and discussed the process of karyotypic evolution in the Galliformes. Comparative chromosome painting confirmed the previous data on chromosome rearrangements obtained by G-banding analysis, and identified several novel chromosome rearrangements. The process of the evolutionary changes of macrochromosomes in the 13 species was in good accordance with the molecular phylogeny, and the ancestral karyotype of the Galliformes is represented.