Staphylotrichum boninense, a new hyphomycete (Chaetomiaceae) from soils in the Bonin Islands, Japan

Staphylotrichum boninense, a new hyphomycete classified in the Chaetomiaceae (Ascomycota), was isolated from soils in the Bonin Islands, Japan. It is characterized morphologically by the production of yellow-orange colonies and subglobose holoblastic conidia. Morphologically the species is similar to S. coccosporum, but it is significantly different from S. coccosporum in phylogeny and also differs with respect to its secondary metabolite profile.     

Analysis of the saccharification capability of high-functional cellulase JN11 for various pretreated biomasses through a comparison with commercially available counterparts

Although the capabilities of Trichoderma reesei cellulases have been greatly improved, these enzymes are still too costly for commercial use. The aim of this research was to assess the biomass saccharification capability of JN11, a recombinant cellulase, compared with that of the commercially available cellulases Accellerase 1500 and Cellic CTec. The activities of JN11, Accellerase 1500, and Cellic CTec were compared by using various types of cellulosic biomass, including rice straw, Erianthus, eucalyptus, and Japanese cedar. JN11 had higher saccharification capability for rice straw, Erianthus, eucalyptus, and Japanese cedar compared with the commercial cellulases. The JN11 saccharification of cellulosic biomasses, including hemicellulose (NaOH-pretreated biomasses), resulted in high glucose and xylose yields because of the high xylanase/xylosidase activity of JN11. Moreover, even JN11 saccharification of hemicellulose-free biomasses (sulfuric acid-, hydrothermally, and steam exploded-pretreated biomasses) resulted in high glucose yields. The cellulase activity of JN11, however, was comparable to that of its commercial counterparts. These findings indicate that the saccharification ability of cellulase is unrelated to its cellulase activity when measured against Avicel, CMC, pNP-lactoside, and other substrates. JN11 showed high activity for all types of pretreated cellulosic biomasses, indicating its usefulness for saccharification of various cellulosic biomasses.     

Rimmed Vacuoles in Becker Muscular Dystrophy Have Similar Features with Inclusion Myopathies

Rimmed vacuoles in myofibers are thought to be due to the accumulation of autophagic vacuoles, and can be characteristic in certain myopathies with protein inclusions in myofibers. In this study, we performed a detailed clinical, molecular, and pathological characterization of Becker muscular dystrophy patients who have rimmed vacuoles in muscles. Among 65 Becker muscular dystrophy patients, we identified 12 patients who have rimmed vacuoles and 11 patients who have deletions in exons 45–48 in DMD gene. All patients having rimmed vacuoles showed milder clinical features compared to those without rimmed vacuoles. Interestingly, the rimmed vacuoles in Becker muscular dystrophy muscles seem to represent autophagic vacuoles and are also associated with polyubiquitinated protein aggregates. These findings support the notion that rimmed vacuoles can appear in Becker muscular dystrophy, and may be related to the chronic changes in muscle pathology induced by certain mutations in the DMD gene.     

Inhibition of TDP-43 Accumulation by Bis(thiosemicarbazonato)-Copper Complexes

Amyotrophic lateral sclerosis (ALS) is a progressive, fatal, motor neuron disease with no effective long-term treatment options. Recently, TDP-43 has been identified as a key protein in the pathogenesis of some cases of ALS. Although the role of TDP-43 in motor neuron degeneration is not yet known, TDP-43 has been shown to accumulate in RNA stress granules (SGs) in cell models and in spinal cord tissue from ALS patients. The SG association may be an early pathological change to TDP-43 metabolism and as such a potential target for therapeutic intervention. Accumulation of TDP-43 in SGs induced by inhibition of mitochondrial activity can be inhibited by modulation of cellular kinase activity. We have also found that treatment of cells and animal models of neurodegeneration, including an ALS model, with bioavailable bis(thiosemicarbazonato)copper(II) complexes (Cu(II)(btsc)s) can modulate kinase activity and induce neuroprotective effects. In this study we examined the effect of diacetylbis(-methylthiosemicarbazonato)copper(II) (Cu(II)(atsm)) and glyoxalbis(-methylthiosemicarbazonato)copper(II) (Cu(II)(gtsm)) on TDP-43-positive SGs induced in SH-SY5Y cells in culture. We found that the Cu(II)(btsc)s blocked formation of TDP-43-and human antigen R (HuR)-positive SGs induced by paraquat. The Cu(II)(btsc)s protected neurons from paraquat-mediated cell death. These effects were associated with inhibition of ERK phosphorylation. Co-treatment of cultures with either Cu(II)(atsm) or an ERK inhibitor, PD98059 both prevented ERK activation and blocked formation of TDP-43-and HuR-positive SGs. Cu(II)(atsm) treatment or ERK inhibition also prevented abnormal ubiquitin accumulation in paraquat-treated cells suggesting a link between prolonged ERK activation and abnormal ubiquitin metabolism in paraquat stress and inhibition by Cu. Moreover, Cu(II)(atsm) reduced accumulation of C-terminal (219-414) TDP-43 in transfected SH-SY5Y cells. These results demonstrate that Cu(II)(btsc) complexes could potentially be developed as a neuroprotective agent to modulate neuronal kinase function and inhibit TDP-43 aggregation. Further studies in TDP-43 animal models are warranted.     

Glycosylation-dependent interactions of C-type lectin DC-SIGN with colorectal tumor-associated Lewis glycans impair the function and differentiation of monocyte-derived dendritic cells

Dendritic cells (DCs) are APCs that play an essential role by bridging innate and adaptive immunity. DC-specific intercellular adhesion molecule-3-grabbing nonintegrin (DC-SIGN) is one of the major C-type lectins expressed on DCs and exhibits high affinity for nonsialylated Lewis (Le) glycans. Recently, we reported the characterization of oligosaccharide ligands expressed on SW1116, a typical human colorectal carcinoma recognized by mannan-binding protein, which is a serum C-type lectin and has similar carbohydrate-recognition specificities as DC-SIGN. These tumor-specific oligosaccharide ligands were shown to comprise clusters of tandem repeats of Lea/Leb epitopes. In this study, we show that DC-SIGN is involved in the interaction of DCs with SW1116 cells through the recognition of aberrantly glycosylated forms of Lea/Leb glycans on carcinoembryonic Ag (CEA) and CEA-related cell adhesion molecule 1 (CEACAM1). DC-SIGN ligands containing Lea/Leb glycans are also highly expressed on primary cancer colon epithelia but not on normal colon epithelia, and DC-SIGN is suggested to be involved in the association between DCs and colorectal cancer cells in situ by DC-SIGN recognizing these cancer-related Le glycan ligands. Furthermore, when monocyte-derived DCs (MoDCs) were cocultured with SW1116 cells, LPS-induced immunosuppressive cytokines such as IL-6 and IL-10 were increased. The effects were significantly suppressed by blocking Abs against DC-SIGN. Strikingly, LPS-induced MoDC maturation was inhibited by supernatants of cocultures with SW1116 cells. Our findings imply that colorectal carcinomas affecting DC function and differentiation through interactions between DC-SIGN and colorectal tumor-associated Le glycans may induce generalized failure of a host to mount an effective antitumor response.     

Identification of a new mutagen, 4,4'-diamino-3,3'-dichloro-5-nitrobiphenyl, in river water flowing through an industrial area in Wakayama, Japan

3,3'-Dichlorobenzidine (DCB), which has been assigned as a possible carcinogen to humans (Group 2B) by IARC, is produced as a raw material in the manufacture of polymers and dye intermediates. In our previous paper, we identified DCB as an indirect-acting mutagenic constituent in the water concentrates from the Waka River, which flows through an industrial area in Wakayama, Japan. In this study, we have identified a novel mutagen in the water samples from the Waka River. Organic chemicals in the river water were adsorbed to blue rayon at the site where effluents from chemical plants and a sewage plant were discharged into the river. The adsorbate was highly mutagenic in Salmonella YG1024 in the presence and absence of S9 mix, inducing 440,000 and 170,000 revertants/g blue rayon equivalent, respectively. Two mutagenic fractions, which accounted for 18% and 12% of the total mutagenicity of the water concentrate in YG1024 with S9 mix, were separated by HPLC with a reversed-phase column following Sephadex LH20 column chromatography. Both fractions were further separated by HPLC using reversed-phase columns. On the basis of spectral analysis and co-chromatography using an authentic chemical standard, one mutagen in the former fraction was identified as DCB and one mutagen in the latter fraction was deduced to be a novel chemical, a 5-nitro derivative of DCB (5-nitro-DCB; 4,4'-diamino-3,3'-dichloro-5-nitrobiphenyl). 5-Nitro-DCB showed strong mutagenicity in YG1024 especially with S9 mix, inducing 24,200 revertants/microg. 5-Nitro-DCB was detected in water concentrates in the range from less than detection limit to 6.9 microg/g of blue rayon. DCB was also detected in the range from 13.2 to 104 micro/g of blue rayon. These results demonstrate that Waka River water might be continually contaminated with the indirect-acting mutagens DCB and 5-nitro-DCB as major mutagenic constituents of the river water.     

Genotoxic activation of 2-phenylbenzotriazole-type compounds by human cytochrome P4501A1 and N-acetyltransferase expressed in Salmonella typhimurium umu strains

Four 2-phenylbenzotriazole (PBTA)-type compounds (PBTA-4, PBTA-6, PBTA-7, and PBTA-8) were identified as major mutagens in blue cotton/rayon-adsorbed substances collected at sites below textile dyeing factories or municipal water treatment plants treating domestic waste and effluents from textile dyeing factories in several rivers in Japan. The main purpose of this study is to understand the basis of the roles of human cytochrome P450 (CYP) and N-acetyltransferases (NATs) in genotoxic activation of PBTA derivatives. We compared the induction of umuC gene expression as a measure of genotoxicity using Salmonella typhimurium TA1535/pSK1002 (parental strain), NM2009 (bacterial O-acetyltransferase-overexpressing strain) established in our laboratories. PBTA-4, PBTA-6, PBTA-7, and PBTA-8 induced the umuC gene expression more strongly in the bacterial O-acetyltransferase-overproducing strain than in the parental strain in the presence of rat S9 mix. We determined the activation of PBTA derivatives by cDNA-based recombinant (Trichoplusia ni) systems expressing human or rat cytochrome P450 enzymes (P450 or CYP) and NADPH-P450 reductase using S. typhimurium NM2009. The results showed that human recombinant CYP1A1 enzyme was much more active than CYP1A2 and CYP3A4 in the genotoxic activation of PBTA-4, PBTA-6, PBTA-7, and PBTA-8. Similarly, rat recombinant CYP1A1 enzyme catalyzed the activation of these chemicals at high rates. alpha-Naphthoflavone, a known inhibitor of CYP1A1, was found to inhibit genotoxic activation caused by PBTA derivatives. We further determined the activation of PBTA derivatives using S. typhimurium NM6001 (human NAT1-expressing strain), S. typhimurium NM6002 (human NAT2-expressing strain), and S. typhimurium NM6000 (O-AT-deficient parent strain) in the presence of S9 mix. PBTA-4 showed almost similar sensitivity in the NAT1-expressing strain and the NAT2-expressing strain, although NAT2-expressing strain exhibited relatively higher sensitivity to PBTA-6, PBTA-7, and PBTA-8 than NAT1-expressing strain. The results support the view that O-acetylation by human NAT1 and NAT2 enzymes is involved in the genotoxic activation of PBTA compounds. These results demonstrate for the first time that human P4501A1 and NATs (NAT1 and NAT2) contribute significantly to the activation of PBTA-type compounds to genotoxic metabolites that induce umuC gene expression in S. typhimurium tester strains.     

Synaptic interaction between ghrelin- and ghrelin-containing neurons in the rat hypothalamus

Synaptic relationships between ghrelin-like immunoreactive axon terminals and other neurons in the hypothalamic arcuate nucleus (ARC) were studied using immunostaining methods at the light and electron microscope levels. Many ghrelin-like immunoreactive axon terminals were found to be in apposition to ghrelin-like immunoreactive neurons at the light microscopic level. At the electron microscopic level, ghrelin-like immunoreactive axon terminals were found to make synapses on ghrelin-like immunoreactive cell bodies and dendrites in the ARC. While the axo-dendritic synapses between ghrelin- and ghrelin-like immunoreactive neurons were mostly the asymmetric type, the axo-somatic synapses were both asymmetric and symmetric type of synapses. Ghrelin at 10(-10) M increased cytosolic Ca(2+) concentration ([Ca(2+)](i)) in the neurons isolated from the ARC, some of which were immunocytochemically identified as ghrelin-positive. Ghrelin at 10(-10) M also increased [Ca(2+)](i) in 12% of ghrelin-like immunoreactive neurons in the ARC. These findings suggest that ghrelin serves as a transmitter and/or modulator that stimulates [Ca(2+)](i) signaling in ghrelin neurons of the ARC, which may participate in the orexigenic action of ghrelin. Our data suggests a possibility of existing a novel circuit implicating regulation of feeding and/or energy metabolism.     

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.