Paraquat Resistant Tobacco Calluses with Enhanced Superoxide Dismutase Activity

Seven paraquat resistant calluses of tobacco (Nicotiana tabacumL. cv. Samsun) were obtained by three successive screeningsof protoplast-derived calluses on a paraquat containing medium.Superoxide dismutase (SOD) activity of the resistant calluseswas 14- to 159-fold that of the leaf cells on protein basis.Paraquat-resistant calluses, however, showed little increasein catalase and peroxidase activities. More than 90% of SODactivity in the resistant calluses was inhibited by KCN, aswas the SOD activity in leaves, indicating that the major SODin the callus appears to be the Cu, Zn containing enzyme. Thecallus cells, however, expressed the immunologically distinguishedSOD isozyme from the enzyme in the leaves. (Received April 23, 1984; Accepted August 6, 1984)     

A simple microinjection technique not employing a micromanipulator

A new microinjection method is presented in which a modified condenser is used instead of a conventional micromanipulator. The micropipette is located in a hole through the optical axis of the condenser lens of a normal microscope. The three-dimensional movement of the micropipette is simply controlled by manipulation of the adjusting screws controlling the movement of the condenser. In comparison with conventional microinjection instruments, the simplicity of this new instrument is outstanding.     

Expression vectors for chicken–human chimeric antibodies

The chicken is a useful animal for preparation of antibodies that are reactive with highly conserved mammalian molecules. For further clinical application of chicken antibodies, we constructed the novel expression vectors for chicken–human chimeric antibodies, pcSLCγ1, pcSLCγ4 and pcSLCκ. These vectors had the following characteristics: (1) any chicken variable regions from hybridomas or a phage display library can be easily introduced; (2) the variable regions are able to be expressed in different immunoglobulin isotypes; and (3) the chimeric antibodies can be highly expressed in either transiently or stably transfected eukaryotic cells (COS-7 and CHO-K1 cells). Western blot analysis of the chimeric antibodies revealed that the expressed products were of the predicted size, structure and specificity. These results indicate that these vectors are useful tools for the chimerization of chicken antibodies.     

The Role of Barrier Islands in Subsistence of the Inhabitants of Roviana Lagoon,Solomon Islands

This multidisciplinary study examines the strategy adopted by villagers in the Roviana Lagoon, South New Georgia, Solomon Islands, to cope with changing socioeconomic and demographic conditions. The study addresses land use, shifting cycles, land tenure, soil nutrients, subsistence production, vegetation, land cover change, and carrying capacity. The results suggested that even if a society had been integrated into the market economy and introduced cash cropping, they used a small island, which was fertile, mainly for traditional shifting cultivation under customary management. However, they used a large area of the main island for cultivation of potentially risky perennial cash crops for private income. This case suggests that a local society is able to develop a harmonized way of rural development, community welfare, and environmental preservation.     

Temperature dependent sorbitol utilization in diapause eggs of the silkworm,Bombyx mori

Summary A series of experiments was conducted to determine whether the interconversion of glycogen and sorbitol at the initiation and termination of diapause in eggs of the silkworm,Bombyx mori was influenced by low temperatures (5°C and 1°C). The conversion of glycogen to sorbitol and glycerol at the initiation of diapause was not affected by exposure to 5°C and 1°C. Chilling diapause eggs at 5°C for over 70 days resulted in a progressive conversion of sorbitol to glycogen. Transfer to 1°C after chilling to 5°C led to a decrease in sorbitol and glycerol conversion. While continuous chilling at 1°C completely inhibited sorbitol utilization for at least 400 days, sorbitol began to decrease immediately following transfer to 5°C. In contrast, glycerol utilization was not prevented by acclimation to 1°C, but a delayed decrease occurred. Continuous exposure to 1°C delayed hatching for a period of 440 days, whereas acclimation to 5°C resulted in 100 per cent hatching by about 100 days. A low, or high acclimation temperature 1°C or 5°C produce different effects on sorbitol utilization and termination of diapause in silkworm eggs.     

In situ monitoring of peptide-bound dsDNA selection on a GCN4-bZIP-immobilized quartz-crystal microbalance.

A highly sensitive 27 MHz quartz-crystal microbalance (QCM) was applied as a device of dsDNA in vitro selection. When GCN4-bZIP peptides were immobilized on the small Au electrode of the QCM, dsDNAs having TGACTCA sequences could be mainly selected from DNA library having a 15-bp random region, which was consistent with the sequence observed by X-ray crystallography.     

Chemical synthesis of branched RNAs: a new method for construction of synthetic units for branched RNAs by use of 2'-phosphorylation on the basis of steric control.

A 3',5'-unprotected 2'-O-bis(tert-butoxy)-phosphinyl-6-N-benzoyladenosine derivative was prepared as a key intermediate for the synthesis of branched RNAs, and used for construction of building units from which chain elongation in any of 2'-, 3'-, and 5'-directions would be possible. From this synthetic intermediate, 2'-phosphorylated ApC dimer was also synthesized.