Showing papers by "Hiroshi Maeda published in 2005"

Genome sequencing and analysis of Aspergillus oryzae

Abstract: The genome of Aspergillus oryzae, a fungus important for the production of traditional fermented foods and beverages in Japan, has been sequenced. The ability to secrete large amounts of proteins and the development of a transformation system have facilitated the use of A. oryzae in modern biotechnology. Although both A. oryzae and Aspergillus flavus belong to the section Flavi of the subgenus Circumdati of Aspergillus, A. oryzae, unlike A. flavus, does not produce aflatoxin, and its long history of use in the food industry has proved its safety. Here we show that the 37-megabase (Mb) genome of A. oryzae contains 12,074 genes and is expanded by 7-9 Mb in comparison with the genomes of Aspergillus nidulans and Aspergillus fumigatus. Comparison of the three aspergilli species revealed the presence of syntenic blocks and A. oryzae-specific blocks (lacking synteny with A. nidulans and A. fumigatus) in a mosaic manner throughout the genome of A. oryzae. The blocks of A. oryzae-specific sequence are enriched for genes involved in metabolism, particularly those for the synthesis of secondary metabolites. Specific expansion of genes for secretory hydrolytic enzymes, amino acid metabolism and amino acid/sugar uptake transporters supports the idea that A. oryzae is an ideal microorganism for fermentation.

Purification and characterization of a biodegradable plastic-degrading enzyme from Aspergillus oryzae.

Abstract: We used biodegradable plastics as fermentation substrates for the filamentous fungus Aspergillus oryzae. This fungus could grow under culture conditions that contained emulsified poly-(butylene succinate) (PBS) and emulsified poly-(butylene succinate-co-adipate) (PBSA) as the sole carbon source, and could digest PBS and PBSA, as indicated by clearing of the culture supernatant. We purified the PBS-degrading enzyme from the culture supernatant, and its molecular mass was determined as 21.6 kDa. The enzyme was identified as cutinase based on internal amino acid sequences. Specific activities against PBS, PBSA and poly-(lactic acid) (PLA) were determined as 0.42 U/mg, 11 U/mg and 0.067 U/mg, respectively. To obtain a better understanding of how the enzyme recognizes and hydrolyzes PBS/PBSA, we investigated the environment of the catalytic pocket, which is divided into carboxylic acid and alcohol recognition sites. The affinities for different substrates depended on the carbon chain length of the carboxylic acid in the substrate. Competitive inhibition modes were exhibited by carboxylic acids and alcohols that consisted of C4-C6 and C3-C8 chain lengths, respectively. Determination of the affinities for different chemicals indicated that the most preferred substrate for the enzyme would consist of butyric acid and n-hexanol.

Isolation, identification, and structure of a potent alkyl-peroxyl radical scavenger in crude canola oil, canolol.

Abstract: Alkylhydroperoxides in oxidized oil are undesirable components because they become alkylperoxyl radicals (ROO*) in the presence of heme, hemoglobin, or myoglobin in red meat ROO* are biochemically reactive and damage nucleic acids and proteins, thereby harming living cells We isolated a component, a highly potent ROO* scavenger, from crude canola oil (rapeseed), which we designated canolol, and identified its chemical structure, 4-vinyl-2,6-dimethoxyphenol The canolol content of crude canola oil greatly increased after the seed was roasted as compared with that from unroasted seed, but it decreased in highly purified oil This anti-ROO* activity was highest in crude oil, deceased after each refining step, and was lowest in highly purified refined oil Canolol was thus generated during roasting As shown previously, canolol is one of the most potent anti-ROO* components in crude canola oil and its potency is much greater than that of well-known antioxidants, including alpha-tocopherol, vitamin C, beta-carotene, rutin, and quercetin

The fungal hydrophobin RolA recruits polyesterase and laterally moves on hydrophobic surfaces.

Abstract: When fungi grow on plant or insect surfaces coated with wax polyesters that protect against pathogens, the fungi generally form aerial hyphae to contact the surfaces. Aerial structures such as hyphae and conidiophores are coated with hydrophobins, which are surface-active proteins involved in adhesion to hydrophobic surfaces. When the industrial fungus Aspergillus oryzae was cultivated in a liquid medium containing the biodegradable polyester polybutylene succinate-coadipate (PBSA), the rolA gene encoding hydrophobin RolA was highly transcribed. High levels of RolA and its localization on the cell surface in the presence of PBSA were confirmed by immunostaining. Under these conditions, A. oryzae simultaneously produced the cutinase CutL1, which hydrolyses PBSA. Pre-incubation of PBSA with RolA stimulated PBSA degradation by CutL1, suggesting that RolA bound to the PBSA surface was required for the stimulation. Immunostaining revealed that PBSA films coated with RolA specifically adsorbed CutL1. Quartz crystal microbalance analyses further demonstrated that RolA attached to a hydrophobic sensor chip specifically adsorbed CutL1. Circular dichroism spectra of soluble-state RolA and bound RolA suggested that RolA underwent a conformational change after its adsorption to hydrophobic surfaces. These results suggest that RolA adsorbed to the hydrophobic surface of PBSA recruits CutL1, resulting in condensation of CutL1 on the PBSA surface and consequent stimulation of PBSA hydrolysis. A fluorescence recovery after photobleaching experiment on PBSA films coated with FITC-labelled RolA suggested that RolA moves laterally on the film. We discuss the novel molecular functions of RolA with regard to plastic degradation.

Immunoglobulin superfamily receptor translocation associated 2 protein on lymphoma cell lines and hairy cell leukemia cells detected by novel monoclonal antibodies.

Abstract: Purpose: The immunoglobulin superfamily receptor translocation associated 2 (IRTA2) gene encodes a cell surface receptor homologous to the family of Fc receptors. Because of the restricted expression of mRNA in B cell–lineage cells, IRTA2 is a new potential target for the immunotherapy of B cell malignancies. To study the expression of the IRTA2 gene product, we produced monoclonal antibodies (MAbs) specific to IRTA2. Experimental Design: A mouse used for cell fusion was DNA-immunized with an expression plasmid encoding the IRTA2 cDNA. The reactivity of MAbs secreted from the hybridomas were characterized with recombinant proteins of IRTA family members in an enzyme immunoassay and a fluorescence-activated cell sorter (FACS). Nineteen human lymphoma cell lines and blood cells from five patients with hairy cell leukemia (HCL) were analyzed with IRTA2 expression using FACS. Results: Three MAbs (F25, F56, and F119) were selected based on their specific reactivity with recombinant IRTA2 and lack of cross-reactivity with other IRTA family members. In a FACS analysis, MAbs F56 and F119 detected IRTA2 expression in six of seven B cell non–Hodgkin9s lymphoma and one of six Burkitt9s lymphoma cell lines. Reverse transcriptase-PCR experiments and Western blotting using MAb F25 confirmed the expression profile. We also found that HCL cells from five patients expressed IRTA2. Conclusions: Our results provide the first evidence that IRTA2 is expressed on the surface of human lymphoma cell lines and HCL cells. IRTA2 could be useful as a new target for immunotherapy.

Intrinsic Josephson junctions in Y1Ba2Cu3Ox single-crystal whiskers grown using Te-doped precursors

Abstract: Single-crystal whiskers of Y1Ba2Cu3Ox with a length of about 5mm were grown from a Te-doped precursor. The optimum nominal composition of the precursors was Y2Ba3Cu3Te0.5Ox. From the energy-dispersive x-ray spectroscopy measurement, Te was not detected in the whiskers. The current-voltage (I-V) characteristics along the c axis of an annealed in vacuum whisker exhibit a clear multibranched structure and a hysteresis curve corresponding to intrinsic Josephson junctions.

Protective effect of melatonin on human peripheral blood hematopoeitic stem cells against doxorubicin cytotoxicity.

Abstract: Background: The dose-limiting toxicity of doxorubicin on hematopoietic stem cells reduces the maximum benefit from this powerful drug. Melatonin may play a role in reducing this toxicity. Materials and Methods: Melatonin at 10 IM was used while challenging human peripheral blood stem cells (PBSC) with doxorubicin (0.6 IM and 1 IM), and colony formation was used to evaluate the protective effect of melatonin. Results: Melatonin was protective for the myeloid and erythroid series when given during or 1 hour after, but not before, doxorubicin, as measured by colony assay. This protection was independent from its antioxidant function as measured by 2', 7'- dichlodihydro-fluorescein diacetate and was selective for PBSC when compared to the MCF-7 cancer cell line. Conclusion: The results suggest the importance of the time sequence for melatonin administration to exert its protective effect in relation to doxorubicin treatment, as well as its protective effect on both erythroid and myeloid elements independent from its antioxidant function. The toxicity of chemotherapeutic agents to normal tissues is critical in determining both the dose and the frequency of drug administration. Many drugs cause toxicity because of their preferential activity against rapidly proliferating cells. Normal tissues that maintain high rates of cell proliferation, such as bone marrow cells, limit the dose of drugs that can be prescribed for cancer patients (1). Many studies suggested a role for different antioxidants in chemoprotection. Lipids, which are major constituents of cellular membranes, are easily oxidized and damaged by free radicals, a process referred to as lipid peroxidation. This process is self-propagating once initiated (2). It was reported that antioxidant supplementation prior to conditioning chemotherapy reduces bone marrow toxicity due to peroxidation processes in bone marrow- transplant recipients (3). Among the antioxidants, melatonin, N-acetyl- 5-methoxytryptamine, a hormonal product of the pineal gland, is one of the most potent agents (4). Along with its antioxidant function, it was also suggested to play a role in hematopoiesis both in vitro and in vivo (5-7). In this study, the protective effect of melatonin on human peripheral hematopoeitic stem cells was investigated after treatment with the cytotoxic anticancer drug, doxorubicin.

Growth of Y1Ba2Cu3Ox Single-Crystal Whisker Using Sb-doped Precursor

Abstract: Single-crystal whiskers of Y1Ba2Cu3Ox with a length of approximately 4 mm were grown from an Sb-doped precursor. The optimum nominal composition of precursors in this Sb-doping method is Y2Ba2.75Cu3Sb0.5Ox. Sb is not detected in the whiskers by energy-dispersive X-ray spectroscopy. The standard 4-probe transport measurements for the as-grown whiskers show a critical temperature TC of approximately 90 K and a c-axis critical current density JC of 6.57 ×104 A/cm2 at 89 K.

Electrostatic shielding structure for stationary induction apparatus

Abstract: PROBLEM TO BE SOLVED: To provide an electrostatic shielding structure for a stationary induction apparatus which is resistant to a mechanical force in the radial direction of a acting on a shielding plate and is capable of suppressing rise in the local field. SOLUTION: The electrostatic field structure of the stationary induction apparatus provided with the electrostatic shielding plate 4 between a coaxially wound primary coil and a coaxially wound secondary coil. The electrostatic shielding plate 4 is divided into a plurality of plates in a direction of the periphery. Side ends 10a, 10b, 11a, 11b, adjacent to the divided electrostatic shielding plate 4, are superimposed by having each sandwiching an insulating material 12 therebetween. COPYRIGHT: (C)2006,JPO&NCIPI

Air-core reactor

Abstract: PROBLEM TO BE SOLVED: To provide an air-core reactor which is simple in configuration, easily formed into coils, and reduced in weight and in size. SOLUTION: Plate-like metal materials 1 and 1 are laminated into a conductive member 2, insulating sheets 3 and 4 different from each other in kind are laminated into an insulating member 5, and the conductive member 2 and the insulating member 5 are stacked up and rolled up into the coils 6. The insulating sheets 3 and 4 of different kinds are used as an inter-turn insulator, so that the insulating sheets 3 and 4 are improved in sliding properties between them, insulating media such as the conductive member 2 and the insulating member 5 are easily formed into a coil, and the coil is impregnated well with an insulating medium. COPYRIGHT: (C)2006,JPO&NCIPI

Rail current detector

Abstract: PROBLEM TO BE SOLVED: To provide a rail current detector capable of reliably detecting presence/absence of the load current with a simple configuration, and reliably opening a disconnector, accordingly. SOLUTION: The rail current detector comprises a detection means 12 which detects the AC current running in a rail 11 and outputs the signal according to the AC current when an electric vehicle is connected to a trolley cable 24, a determination means 13 to output the determination signal when the rail current detected by the detection means 12 is equal to or greater than a predetermined value, and a display means 15 to perform the display corresponding to presence/absence of the AC current running in the rail 11, and further comprises a blocking means 16 to block the operation of a disconnector 23 connected to the trolley cable 24 by the input of the determination signal. COPYRIGHT: (C)2006,JPO&NCIPI