Notes on some plant-inhabiting fungi collected from the Nansei Islands (1)

In the course of a survey on plant diseases and their pathogenic fungi in the Nansei Islands, some noteworthy fungi were collected. Among them, four fungi newly found in Japan were described with some mycological and pathological notes. These species are Septoria gardeniae Savelli, causing circular leaf spot of Gardenia; Phyllosticta cordylinophila Young apud Stevens, causing brown leaf spot of Cordyline; Phyllosticta drummondii Vanef et van der Aa, causing brown needle blight of Araucaria; and Phyllachora minuta Hennings, causing tar spot of Hibiscus.     

Involvement of Oct3/4 in the enhancement of neuronal differentiation of ES cells in neurogenesis-inducing cultures

Oct3/4 plays a critical role in maintaining embryonic stem cell pluripotency. Regulatable transgene-mediated sustained Oct3/4 expression in ES cells cultured in serum-free LIF-deficient medium caused accelerated differentiation to neuroectoderm-like cells that expressed Sox2, Otx1 and Emx2 and subsequently differentiated into neurons. Neurogenesis of ES cells is promoted by SDIA (stromal cell-derived inducing activity), which accumulates on the PA6 stromal cell surface. Oct3/4 expression in ES cells was maintained by SDIA whereas without it expression was promptly downregulated. Suppression of Oct3/4 abolished neuronal differentiation even after stimulation by SDIA. In contrast, sustained upregulated Oct3/4 expression enhanced SDIA-mediated neurogenesis of ES cells. Therefore, Oct3/4 appears to promote neuroectoderm formation and subsequent neuronal differentiation from ES cells.     

Addition and re-examination of Japanese species belonging to the genus <Emphasis Type="Italic">Cercospora </Emphasis>and allied genera. V. Collections from the Nansei Islands (2)

 Five species collected in the Nansei Islands are discussed. Of these, one species found on Gardenia jasminoides is described as a new species, Cercosporidium okinawaense Kobayashi et Nishijima. Asperisporium caricae on Carica papaya, Pseudocercospora melastomobia on Melastoma candidum, and P. neoliquidambaris Nakashima et Kobayashi, nom. nov. on Liquidambar formosana are newly added to the Japanese mycoflora. Cercospora violamaculans on Rhaphiolepis umbellata is transferred to the genus Pseudocercospora as Pseudocercospora violamaculans (Fukui) Kobayashi et Nakashima, comb. nov., with some additional notes. Received: October 26, 2001 / Accepted: March 13, 2002     

Two novel mouse genes--Nubp2, mapped to the t-complex on chromosome 17, and Nubp1, mapped to chromosome 16--establish a new gene family of nucleotide-binding proteins in eukaryotes.

Two novel mouse genes and one novel human gene that define distinctive eukaryotic nucleotide-binding proteins (NUBP) and are related to the mrp gene of prokaryotes are characterized. Phylogenetic analyses of the genes, encoding a short form (Nubp2) and a long form (Nubp1) of NUBP, clearly establish them as a new NUBP/MRP gene family that is well conserved throughout phylogeny. In addition to conserved ATP/GTP-binding motifs A (P-loop) and A', members of this family share at least two highly conserved sequence motifs, NUBP/MRP motifs alpha and beta. Only one type of NUBP/MRP gene has been observed thus far in prokaryotes, but there are two types in eukaryotes. One group includes mouse Nubp1, human NBP, yeast NBP35, and Caenorhabditis elegans F10G8.6 and is characterized by a unique N-terminal sequence with four cysteine residues that is lacking in the other group, which includes mouse Nubp2, human NUBP2, and yeast YIA3w. Northern blot analyses of the two mouse genes show distinctive patterns consistent with this classification. Mouse Nubp2 is mapped to the t-complex region of mouse Chromosome 17, whereas Nubp1 is mapped to the proximal region of mouse Chromosome 16. Interestingly, both regions are syntenic with human chromosome 16p13.1-p13.3, suggesting that a chromosomal breakage between Nubp2 and Nubp1 probably occurred during the evolution of mouse chromosomes.     

Double antenna structure of chicken prolactin receptor deduced from the cDNA sequence.

Chicken prolactin receptor (cPRLR) deciphered from the cDNA sequence showed a unique double antenna structure in its extracellular domain. The predicted cPRLR preprotein was composed of 831 amino acids and contained a signal peptide and a transmembrane region. The extracellular domain comprised 438 residues, and was divided into two tandemly repeated, highly homologous units, each of which corresponded to the extracellular domains of mammalian prolactin receptors. Both extracellular units of cPRLR possessed two structural features characteristic of the ligand binding units of cytokine/prolactin receptor family, namely two pairs of cysteine residues and a WSXWS motif. These findings strongly suggest that cPRLR contains two repeated ligand binding units, that is a double antenna structure. The cPRLR gene is expressed in a wide range of tissues of laying hen.     

2-Cyclohexylcarbonylbenzimidazoles as potent,orally available and brain-penetrable opioid receptor-like 1 (ORL1) antagonists

The synthesis and biological evaluation of new potent opioid receptor-like 1 (ORL1) antagonists are presented. Conversion of the thioether linkage of the prototype [It is reported prior to this communication as a consecutive series.: Kobayashi, K.; Kato, T.; Yamamoto, I.; Shimizu, A.; Mizutani, S.; Asai, M.; Kawamoto, H.; Ito, S.; Yoshizumi, T.; Hirayama, M.; Ozaki, S.; Ohta, H.; Okamoto, O. Bioorg. Med. Chem. Lett., in press] to the carbonyl linker effectively reduces susceptibility to P-glycoprotein (P-gp) efflux. This finding led to the identification of 2-cyclohexylcarbonylbenzimizole analogue 7c, which exhibited potent ORL1 activity, excellent selectivity over other receptors and ion channels, and poor susceptibility to P-gp. Compound 7c also showed satisfactory pharmacokinetic profiles and brain penetrability in laboratory animals. Furthermore, 7c showed good in vivo antagonism. Hence, 7c was selected as a clinical candidate for a brain-penetrable ORL1 antagonist.     

Osteoclast‐specific Dicer gene deficiency suppresses osteoclastic bone resorption

Osteoclasts are unique cells that resorb bone, and are involved in not only bone remodeling but also pathological bone loss such as osteoporosis and rheumatoid arthritis. The regulation of osteoclasts is based on a number of molecules but full details of these molecules have not yet been understood. MicroRNAs are produced by Dicer cleavage an emerging regulatory system for cell and tissue function. Here, we examine the effects of Dicer deficiency in osteoclasts on osteoclastic activity and bone mass in vivo. We specifically knocked out Dicer in osteoclasts by crossing Dicer flox mice with cathepsin K‐Cre knock‐in mice. Dicer deficiency in osteoclasts decreased the number of osteoclasts (N.Oc/BS) and osteoclast surface (Oc.S/BS) in vivo. Intrinsically, Dicer deficiency in osteoclasts suppressed the levels of TRAP positive multinucleated cell development in culture and also reduced NFATc1 and TRAP gene expression. MicroRNA analysis indicated that expression of miR‐155 was suppressed by RANKL treatment in Dicer deficient cells. Dicer deficiency in osteoclasts suppressed osteoblastic activity in vivo including mineral apposition rate (MAR) and bone formation rate (BFR) and also suppressed expression of genes encoding type I collagen, osteocalcin, Runx2, and Efnb2 in vivo. Dicer deficiency in osteoclasts increased the levels of bone mass indicating that the Dicer deficiency‐induced osteoclastic suppression was dominant over Dicer deficiency‐induced osteoblastic suppression. On the other hand, conditional Dicer deletion in osteoblasts by using 2.3 kb type I collagen‐Cre did not affect bone mass. These results indicate that Dicer in osteoclasts controls activity of bone resorption in vivo. J. Cell. Biochem. 109: 866–875, 2010. © 2009 Wiley‐Liss, Inc.     

Fetal Growth Retardation and Lack of Hypotaurine in Ezrin Knockout Mice

Ezrin is a membrane-associated cytoplasmic protein that serves to link cell-membrane proteins with the actin-based cytoskeleton, and also plays a role in regulation of the functional activities of some transmembrane proteins. It is expressed in placental trophoblasts. We hypothesized that placental ezrin is involved in the supply of nutrients from mother to fetus, thereby influencing fetal growth. The aim of this study was firstly to clarify the effect of ezrin on fetal growth and secondly to determine whether knockout of ezrin is associated with decreased concentrations of serum and placental nutrients. Ezrin knockout mice (Ez^−/−) were confirmed to exhibit fetal growth retardation. Metabolome analysis of fetal serum and placental extract of ezrin knockout mice by means of capillary electrophoresis–time-of-flight mass spectrometry revealed a markedly decreased concentration of hypotaurine, a precursor of taurine. However, placental levels of cysteine and cysteine sulfinic acid (precursors of hypotaurine) and taurine were not affected. Lack of hypotaurine in Ez^−/− mice was confirmed by liquid chromatography with tandem mass spectrometry. Administration of hypotaurine to heterogenous dams significantly decreased the placenta-to-maternal plasma ratio of hypotaurine in wild-type fetuses but only slightly decreased it in ezrin knockout fetuses, indicating that the uptake of hypotaurine from mother to placenta is saturable and that disruption of ezrin impairs the uptake of hypotaurine by placental trophoblasts. These results indicate that ezrin is required for uptake of hypotaurine from maternal serum by placental trophoblasts, and plays an important role in fetal growth.