Evolutionary relationships of three new species of Enterobacteriaceae living as symbionts of aphids and other insects

Ecological studies on three bacterial lineages symbiotic in aphids have shown that they impose a variety of effects on their hosts, including resistance to parasitoids and tolerance to heat stress. Phylogenetic analyses of partial sequences of gyrB and recA are consistent with previous analyses limited to 16S rRNA gene sequences and yield improved confidence of the evolutionary relationships of these symbionts. All three symbionts are in the Enterobacteriaceae. One of the symbionts, here given the provisional designation "Candidatus Serratia symbiotica," is a Serratia species that has acquired a symbiotic lifestyle. The other two symbionts, here designated "Candidatus Hamiltonella defensa" and "Candidatus Regiella insecticola," are sister groups to one another and together show a relationship to species of Photorhabdus.     

Skin temperature rise induced by calcitonin gene-related peptide in gonadotropin-releasing hormone analogue-treated female rats and alleviation by Keishi-bukuryo-gan, a Japanese herbal medicine

The effects of Keishi-bukuryo-gan on calcitonin gene-related peptide (CGRP)-induced elevation of skin temperature were investigated in gonadotropin-releasing hormone (GnRH) analogue-treated female rats. Leupline (1.0 mg/kg) as the GnRH analogue was subcutaneously (s.c.) injected into female rats. After Keishi-bukuryo-gan (100-1,000 mg/kg, p.o.) or 17beta-estradiol (0.010 mg/kg, s.c.) was administered to GnRH analogue-treated rats for 14 days, CGRP-induced skin temperature elevation, concentration of plasma 17beta-estradiol and pituitary gonadotropin (luteinizing hormone; LH, and follicle stimulating hormone; FSH) were measured. In addition, effects of 17beta-estradiol and Keishi-bukuryo-gan on the proliferation of estrogen-dependent human breast cancer (MCF-7) cells were investigated under in vitro conditions. GnRH analogue significantly lowered the concentrations of plasma 17beta-estradiol and pituitary gonadotropins. Tissue weights of the ovaries and uterus were also decreased by the analogue. Under the condition of estrogen deficiency, intravenous (i.v.) injection of exogenous CGRP (10 microg/kg) elevated the skin temperature of the hind paws more significantly than it did in sham-treated control rats. Estrogen supplementation inhibited this elevation of skin temperature with restoration of both the lowered plasma estrogen level and the decreased uterine weight in GnRH analogue-treated rats. On the other hand, Keishi-bukuryo-gan inhibited the elevation of skin temperature in a dose-dependent manner without restoring the plasma estrogen level and uterine weight. In addition, in an in vitro study, MCF-7 cells proliferated in a dose-dependent manner by the addition of 17beta-estradiol (10(-13)-10(-8) M) to the medium. However, Keishi-bukuryo-gan (10(-6)-10(-4) mg/ml) did not activate the MCF-7 cell proliferation. These results suggest that Keishi-bukuryo-gan, which does not exhibit estrogen activity, may be useful for the treatment of hot flashes in women who are undergoing medical ovariectomy with a GnRH analogue.     

Sonic hedgehog myocardial gene therapy: tissue repair through transient reconstitution of embryonic signaling

Sonic hedgehog (Shh) is a crucial regulator of organ development during embryogenesis. We investigated whether intramyocardial gene transfer of naked DNA encoding human Shh (phShh) could promote a favorable effect on recovery from acute and chronic myocardial ischemia in adult animals, not only by promoting neovascularization, but by broader effects, consistent with the role of this morphogen in embryogenesis. After Shh gene transfer, the hedgehog pathway was upregulated in mammalian fibroblasts and cardiomyocytes. This resulted in preservation of left ventricular function in both acute and chronic myocardial ischemia by enhanced neovascularization, and reduced fibrosis and cardiac apoptosis. Shh gene transfer also enhanced the contribution of bone marrow-derived endothelial progenitor cells to myocardial neovascularization. These data suggest that Shh gene therapy may have considerable therapeutic potential in individuals with acute and chronic myocardial ischemia by triggering expression of multiple trophic factors and engendering tissue repair in the adult heart.     

Phylogeography of the Russian flying squirrel (Pteromys volans): implication of refugia theory in arboreal small mammal of Eurasia

A phylogeographical study of the Russian (Siberian) flying squirrel (Pteromys volans) was carried out using the complete mitochondrial (mt) cytochrome b gene sequences with special reference to the refugia theory for the arboreal traits of this species. We examined 31 specimens from 24 localities, resulting in 28 haplotypes. One breeding specimen with a unique haplotype from Hokkaido, Japan was included in the phylogenetic analysis. There were three mtDNA lineages: Hokkaido, Far Eastern, and northern Eurasia. Divergence data among lineages demonstrated that the Hokkaido group separated from the other groups during the Holsteinian interglacial. The phylogeographical pattern of P. volans is different from that previously reported for terrestrial rodents associated with treeless habitats. Unlike grasslands, forests decreased during glaciation and moved southward because of the cold and arid environmental conditions. The glacial refugia of P. volans would have been associated with forest dynamics in the Pleistocene.     

ICOS costimulates invariant NKT cell activation

It has been reported that costimulatory molecules, CD80/86-CD28 and CD154-CD40, critically contribute to activation of CD1d-restricted invariant NKT (iNKT) cells. Here we have demonstrated that ICOS, a new member of the CD28 family, plays a substantial role in iNKT cell activation. iNKT cells constitutively expressed ICOS as well as CD28 independently, and ICOS expression was further up-regulated 2-3 days after alpha-galactosylceramide (alpha-GalCer) treatment. Blockade of ICOS-mediated costimulation by administration of anti-ICOS ligand (B7RP-1) mAb or by ICOS gene knockout substantially inhibited alpha-GalCer-induced IFN-gamma and IL-4 production, cytotoxic activity, and anti-metastatic effect. Moreover, blockade of both B7RP-1-ICOS and CD80/86-CD28 interactions mostly abolished the alpha-GalCer-induced immune responses. These findings indicate that iNKT cell activation is regulated by CD28 and IOCS independently.     

Estimating the time to the whole-genome duplication and the duration of concerted evolution via gene conversion in yeast

A maximum-likelihood (ML) method is developed to estimate the duration of concerted evolution and the time to the whole-genome duplication (WGD) event in baker's yeast (Saccharomyces cerevisiae). The models with concerted evolution fit the data significantly better than the molecular clock model, indicating a crucial role of concerted evolution via gene conversion after gene duplication in yeast. Our ML estimate of the time to the WGD is nearly identical to the time to the speciation event between S. cerevisiae and Kluyveromyces waltii, suggesting that the WGD occurred in very early stages after speciation or the WGD might have been involved in the speciation event.     

Requirement for Mab21l2 during development of murine retina and ventral body wall

The mab-21 gene was first identified because of its requirement for ray identity specification in Caenorhabditis elegans. It is now known to constitute a family of genes that are highly conserved from vertebrates to invertebrates, and two homologues Mab21l1 and Mab21l2 have been identified in many species. Here we describe the generation of Mab21l2-deficient mice, which have defects in eye and body wall formation. The mutant mouse eye has a rudimentary retina, as a result of insufficient invagination of the optic vesicle due to deficient proliferation, causing the absence of lens. The defects in optic vesicle development correlate with reduced expression of Chx10, which is also required for retina development; Rx, Lhx2, and Pax6 expression is not significantly affected. We conclude that Mab21l2 expression is essential for optic vesicle growth and formation of the optic cup, its absence causing reduced expression of Chx10. Mutant mice also display abnormal extrusion of abdominal organs, defects in ventral body wall formation, resulting in death in utero at mid-gestational stage. Our results reveal that Mab21l2 plays crucial roles in retina and in ventral body wall formation.     

Effective accumulation of polyion complex micelle to experimental choroidal neovascularization in rats

Exudative age-related macular degeneration, characterized by choroidal neovascularization (CNV), is a major cause of visual loss. In this study, we examined the distribution of the polyion complex (PIC) micelle encapsulating FITC-P(Lys) in blood and in experimental CNV in rats to investigate whether PIC micelle can be used for treatment of CNV. We demonstrate that PIC micelle has long-circulating characteristics, accumulating to the CNV lesions and is retained in the lesion for as long as 168 h after intravenous administration. These results raise the possibility that PIC micelles can be used for achieving effective drug targeting to CNV.     

No influence of tumor growth by intramuscular injection of hepatocyte growth factor plasmid DNA: safety evaluation of therapeutic angiogenesis gene therapy in mice

Recently, a novel therapeutic treatment for ischemic diseases using angiogenic growth factors to augment collateral artery development has been proposed. As intramuscular injection of naked human hepatocyte growth factor (HGF) plasmid DNA induced therapeutic angiogenesis in several animal test subjects, we have started a clinical trial to treat peripheral arterial disease. However, one might assume that over-expression of angiogenic growth factors could enhance tumor growth. To resolve this issue, we examined the over-expression of HGF in tumor bearing mice. Tumors on their backs were prepared with an intradermal inoculation of A431, human epidermoid cancer cells expressing c-Met. These mice were intramuscularly injected with human HGF plasmid or control plasmid into the femoral muscle. Human HGF concentration was increased only in the femoral muscle, but not in blood. Although recombinant HGF stimulated the growth of A431 cells in vitro, temporally and locally HGF elevation in hindlimb had no effect on tumor growth in mice.