Cloning and functional analysis of the Aspergillus oryzae conidiation regulator gene brlA by its disruption and misscheduled expression

We cloned the brlA gene from Aspergillus oryzae genomic DNA using the A. nidulans brlA gene as a probe. A 3.1-kb EcoRI-BalI genomic DNA fragment was cloned and sequenced. The deduced amino acid sequence revealed 70% identity with A. nidulans BRLA and contained two C2H2 zinc finger motifs in its carboxyl terminus, and the promoter sequence contained a 43-bp highly conserved region, indicating that the cloned gene was an A. oryzae homologue of A. nidulans brlA. Disruption of the brlA gene by homologous recombination resulted in the loss of ability to form conidiophores. These results suggest that the brlA gene of A. oryzae plays a fundamental role in controlling conidiophore development. When the brlA gene was expressed under the control of the amyB promoter in A. oryzae transformants, highly differentiated and compact colonies were observed on a solid medium. The misscheduled expression of the brlA gene in submerged culture, in which conidiation does not normally occur, caused the development of complex conidiophore structures with vesicles, phialides and conidia.     

Properties of the peptides liberated from rice protein in sokujo-moto

In the supernatant of sokujo-moto, a high level of acid carboxypeptidase (ACP) activity and a large amount of peptides were observed, however, the amount of free amino acids liberated was small. In order to determine why these peptides were not hydrolyzed to any significant degree by the ACP, the properties of the peptides in sokujo-moto were investigated in this study. Peptides were fractionated from sokujo-moto by ion exchange column chromatography. ACP purified from rice-koji (rice overgrown with Aspergillus oryzae) was allowed to react with the peptides, and it was found that they were not hydrolyzed to any significant degree by the enzyme. Gel filtration chromatography was performed to ascertain the molecular size distribution of the peptides in sokujo-moto, and it was revealed that they were of low molecular sizes; molecular size: mainly in the range of 200-400, and chain length: 2-3. ACP purified from rice-koji was also allowed to react with various synthetic peptides, and it was found that ACP of rice-koji could not rapidly hydrolyze low-molecular-size peptides, such as dipeptides or tripeptides. Acid protease (AP) purified from rice-koji released peptides of molecular sizes mainly in the range of 300-600 or above from rice protein under acidic conditions (pH 3.6; the pH of sokujomoto). When AP and ACP were allowed to act at the same time on rice protein, mainly low-molecular-size peptides (molecular sizes mainly in the range of 200-400) were produced. From these results, it was estimated that AP released peptides with molecular sizes mainly in the range of 300-600 or above from rice protein and ACP degraded the relatively higher molecular size peptides among them to lower molecular size peptides; consequently only low-molecular-size peptides with molecular sizes mainly in the range of 200-400 were released in the supernatant of sokujo-moto.     

Growth induction of rat primary hepatocytes using antisense oligonucleotides

We examined growth control of adult and fetal hepatocytes by regulating the expression of cell-cycle-related proteins using antisense S-oligonucleotides to tumor suppressors retinoblastoma (RB) protein and p53, and cyclin-dependent kinase (CDK) inhibitors p21 and p27. The protein expression in both adult and fetal hepatocytes was significantly suppressed with the addition of corresponding antisense oligonucleotides at a concentration of 2.5 microM. For the evaluation of growth, 3H-thymidine incorporation and DNA content were measured and the results demonstrated that all the antisense oligonucleotides had growth-promoting effects and the promoting potential was equivalent or slightly greater than that with the addition of hepatocyte growth factor (HGF) (10 ng/ml). The growth-promoting effect of the antisense oligonucleotides was enhanced by HGF in both adult and fetal hepatocyte cultures, and the effects on hepatocyte growth were also observed in a suspension culture.     

A quick and simple method for the identification of meat species and meat products by PCR assay

The polymerase chain reaction (PCR) was applied to identify six meats (cattle, pig, chicken, sheep, goat and horse) as raw materials for products. By mixing seven primers in appropriate ratios, species-specific DNA fragments could be identified by only one multiplex PCR. A forward primer was designed on a conserved DNA sequence in the mitochondrial cytochrome b gene, and reverse primers on species-specific DNA sequences for each species. PCR primers were designed to give different length fragments from the six meats. The products showed species-specific DNA fragments of 157, 227, 274, 331, 398 and 439 bp from goat, chicken, cattle, sheep, pig and horse meats, respectively. Identification is possible by electrophoresis of PCR products. Cattle, pig, chicken, sheep and goat fragments were amplified from cooked meat heated at 100 or 120°C for 30 min, but horse DNA fragments could not be detected from the 120°C sample. Detection limits of the DNA samples were 0.25 ng for all meats.     

A 64-Mb DRAM with meshed power line

A 64-Mb dynamic RAM (DRAM) has been developed with a meshed power line (MPL) and a quasi-distributed sense-amplifier driver (qDSAD) scheme. It realizes high speed, t_RAS=50 ns (typical) at V_cc=3.3 V, and 16-b input/output (I/O). This MPL+qDSAD scheme can reduce sensing delay caused by the metal layer resistance. Furthermore, to suppress crosstalk noise, a V_SS shield peripheral layout scheme has been introduced, which also widens power line widths. This 64-Mb DRAM was fabricated with 0.4-μm CMOS technology using KrF excimer laser lithography. A newly developed memory cell structure, the tunnel-shaped stacked-capacitor cell (TSSC), was adapted to this 64-Mb DRAM     

A vehicular-mounted vertical space diversity antenna for a landmobile radio

A vertical space-diversity antenna has been developed in order to achieve a diversity scheme while maintaining the simple appearance of a trunk-lid antenna. It is shown that small correlation coefficients can be achieved by a separation of approximately 0.5 wavelengths. Differences in the upper and lower antenna radiation patterns are clarified as being caused by mutual coupling of these antennas, and an incoming wave spread of more than 20° is the main reason for reduction of the correlation coefficients. Field tests in the Tokyo metropolitan area have indicated that adequate correlation coefficients and an adequate received signal level can be achieved. Moreover, calculation estimations are confirmed by the experimental results     

1 Tbit/s (111 Gbit/s/ch X 10 ch) no-guard-interval CO-OFDM transmission over 2100 km DSF

Spectrally efficient (2bit/s/Hz) 1 Tbit/s DWDM transmission of 111 Gbit/s no-guard-interval PDM CO-OFDM signals with 50 GHz spacing over DSF is demonstrated. The record transmission distance of 2100 km was achieved for a 100 Gbit/s-data-rate CO-OFDM system.     

Tunable Optical Notch Filter Realized by Shifting the Photonic Bandgap in a Silicon Photonic Crystal Line-Defect Waveguide

A tunable optical notch filter was realized by thermally shifting the TM-like (the light's electric field perpendicular to the substrate) bandgap of a silicon photonic crystal slab W1 line-defect waveguide with silica cladding. This device is compact-its footprint is 340times16 mum², excluding the electrode pads. The 3-dB bandwidth of the device was about 5 nm, and the extinction ratio at the center wavelength was as high as 40 dB. A maximum center wavelength shift of 17.9 nm was attained at a heating power of 0.7W, with a tuning efficiency of 25.5 nm/W. The tuning response time was less than 100 mus     

L-band Er3+-doped fluorophosphate glass-fibre amplifier

The first L-band EDFA to employ fluorophosphate glass as the host glass material has been realised. The lowest fibre loss yet reported for fluorophosphate glass fibre of 0.7 dB/m is achieved. The amplifier achieved a flat gain with an average value of 21.7 dB in the L-band.     

On the mechanisms limiting mobility in InP/InGaAs buried channel nMISFETs

MISFETs incorporating the InP/InGaAs buried channel showed a high peak mobility of 5500 cm²/V s. Spillover of the inversion carriers from the buried channel to the MIS interface on the InP barrier layer caused drastic mobility degradation as the carrier concentration was increased. The spillover was evidenced by observing a negative transconductance and a kink in split capacitance-voltage curves. Remote scattering by the trapped charges at the MIS interface also reduced the mobility when the InP barrier layer was as thin as 2 nm.