Multicopy suppressors of the sly1 temperature-sensitive mutation in the ER-Golgi vesicular transport in Saccharomyces cerevisiae

Saccharomyces cerevisiae Sly1 protein is a member of the Sec1/Munc18-family proteins, which are essential for vesicular trafficking, but their exact biological roles are yet to be determined. A temperature-sensitive sly1 mutant arrests the vesicular transport from the ER to Golgi compartments at 37 degrees C. We screened for multicopy suppressor genes that restore the colony formation of the sly1(ts) mutant to discover functionally interacting components. The suppressor genes obtained were classified as: (1) those that encode a multifunctional suppressor, SSD1; (2) heat shock proteins, SSB1 and SSB2; (3) cell surface proteins, WSC1, WSC2 and MID2; (4) ER-Golgi transport proteins, USO1 and BET1; and (5) an as-yet-uncharacterized protein, HSD1 (high-copy suppressor of SLY1 defect 1). By epitope tagging of the gene product, we found that Hsd1 protein is an ER-resident membrane protein. Its overproduction induced enlargement of ER-like membrane structures.     

Isolation and structural analysis of efficient autonomously replicating sequences (ARSs) of the yeast Candida utilis

The industrially important yeast Candida utilis is widely used in production of food and medical materials, but its host-vector system has not been well developed. We screened for compact and efficient ARSs to construct practically useful vectors. The C. utilis strain AHU3053 was found to be efficiently transformed by the conventional lithium acetate method and was used as the host. The C. utilis IAM4264 genomic library was constructed by inserting the partial Sau3AI digests in pRI51, which has a kanMX gene expressible in C. utilis. By examining 98 C. utilis G418-resistant transformants, five plasmids had the highest ARS activity. By trimming of the inserts, the 1490 and 552 bp fragments with transformation activity of over 10(3)/microg DNA were obtained from ARS3 and ARS4, respectively. Although several sequences identical to S. cerevisiae ARS consensus sequences (ACSs) were found in ARS3 and ARS4, our deletion analysis indicated that these were not essential for the activity. Because the minimal functional ARS fragment was also several-fold larger than that of S. cerevisiae, the C. utilis ARSs have some unique characteristics resembling the Sz. pombe ARSs. These ARSs were functional in other C. utilis strains tested and useful for constructing practical vectors.     

Sub-millimeter-long carbon nanotubes repeatedly grown on and separated from ceramic beads in a single fluidized bed reactor

A semi-continuous fluidized-bed process is reported which rapidly converts acetylene into carbon nanotubes (CNTs). Catalysts are first immobilized on ceramic beads and CNTs are then grown on the beads and then separated from them in a repetitive process accomplished within a single reactor simply by switching gases at a fixed temperature. CNTs of 6–10 nm diameter, three walls on average, 0.4 mm length and 99 wt.% purity were synthesized at an yield of over 70% in a reactor residence time shorter than 0.3 s. The easy and efficient production of such CNTs with in situ separation from the catalysts may accelerate the development of CNT-based nanotechnology industries.     

TRANSIENT THERMOELASTIC CONTACT STRESS IN A SHORT-LENGTH CIRCULAR CYLINDER

This paper is a treatment of a transient thermoelastic contact problem in a short-length circular cylinder, to which a heated rigid band is bonded. The problem may be reduced to that of solving dual-series equations. The solution meets the boundary conditions on both the lateral surface and the plane ends of the cylinder. The radial, hoop, and axial stresses have singularities at the end of a rigid band on the cylindrical surface.     

Shrunk multiline addressing method in a passive‐matrix‐driven liquid powder display

Abstract— A shrunk multiline addressing method (SMLA) in a passive‐matrix‐driven liquid powder display will be discussed. An algorithm to generate SMLA data that effectively reduces the number of scanning lines has been devised. The update time is reduced by 44.5% on average, and this reduction is maintained despite increased sizes of the images. The SMLA data generated by this algorithm is applied to e‐paper panels, thereby confirming the reduction in update time and that the image quality of the panels driven by SMLA is equal to that of conventionally driven ones.     

Hybrid Rational Function Approximation and Its Accuracy Analysis

We propose a rational function approximation method combining numeric and symbolic computations. Given functions or data are first interpolated by a rational function, i.e. the ratio of polynomials. Undesired poles appearing in the rational interpolant are removed by an approximate-GCD method. We call the rational approximation a Hybrid Rational Function Approximation and abbreviate it as HRFA. In this paper we give a short survey of the HRFA and then discuss its accuracy analysis by using the approximate-GCD proposed by Pan.     

MD simulation of atom-order void formation in Ni fcc metal

Atom-order void formation in a defective crystalline material is studied by using molecular dynamics method (MD). Infinite long cylinder, which is constructed with nickel atoms with a line of vacancies, is subjected to multiaxial tensile strain field by moving periodic boundary and the atoms on the outer surface of the cylinder. When the load exceeds a critical value, sudden appearance of the void is observed and it develops rapidly. The developed void does not disappear by only unloading and relaxation, in spite of the system with the void has higher potential energy than that without void. The biaxial or the triaxial load is necessary to the atom order void formation. Moreover, the results by the MD simulations are compared with theoretical solution for nonlinear elastic solid. Received 26 August 1999     

Channel coding scheme for in HDTV digital VCR

The authors have developed an experimental in HDTV digital videocassette recorder (VCR). The VCR can record HDTV digital base-band signals for more than 64 min on a in metal particle (MP) tape. An eight-to-eight modulation ( ) scheme has been developed for this VCR to realize high-density recording. In order to suppress sufficiently the low-frequency components and reduce the occurrence probability of long-run-lengths for the recording data sequence, a new conversion table and bit-rearrangement method have been introduced in this modulation scheme. This conversion table has been particularly structured to reduce run-length using the bit-rearrangement process. Three kinds of typical HDTV images were used to evaluate the performance compared with the scrambled-NRZ method. The run-length distribution and the frequency spectrum were calculated for each image. The results showed that the occurrence probability of long-run-lengths were well reduced and the low-frequency components along with the DC component were sufficiently suppressed. Cross-talk interferences and overwriting noises were also found to be much less than those for the scrambled-NRZ method.     

Site-specific localization of Epstein-Barr virus in pharyngeal carcinomas

Electrospray ionization (ESI) Fourier transform ion cyclotron resonance (FTICR) mass spectrometry has been used to characterize heterotetrameric corynebacterial sarcosine oxidase. By using a conventional quadrupole mass spectrometer, no spectra for the intact complex could be obtained (i.e., electrospraying protein at neutral pH), but spectra showing the four protein subunits were obtained when electrospraying from acidic solution. Initial low resolution ESI-FTICR mass spectra of the intact heterotetramer revealed a typical narrow charge state distribution in the range 6000 < m/z < 9000, consistent with retention of a compact structure in the gas phase, and gave a mass measurement about 1000 u higher than predicted. Efficient in-trap clean up, based upon low energy collisionally induced dissociation of adducts, allowed significant improvement in mass measurement accuracy. The present results represent the largest heteromultimeric protein complex successfully analyzed using FTICR mass spectrometry, and clearly illustrate the importance of sample clean up methods for large molecule characterization.     

Requirements for high-frequency LD FM response in an optical CPFSKheterodyne delay demodulation system

The required high-frequency laser diode (LD) FM responses for a continuous phase frequency shift keying (CPFSK) heterodyne delay modulation system were investigated. The degradations due to insufficient high-frequency FM response are evaluated, considering the FSK waveform distortion, which gives undesired phase error at the demodulation circuit. From the phase error, bit error rate (BER) degradation is calculated. The calculated results indicate that the delay-time adjustment for the demodulation circuit is effective in minimizing the power penalty. The theoretical evaluation, including the demodulation circuit optimization, explains the experimental results fairly well. Using the same evaluation procedure, required high-frequency LD FM responses are derived. The results, together with the required low-frequency FM responses, give guidelines for transmitter LD selection for coherent CPFSK systems