| Research Abstract |
This projects have been organized to investigate the ultrastructures and biotechnological applications of important viruses and plasmids in plants, insects, vertibrates, fungi and bacteria. (1) The ultrastructures of surface and intracellular appearance of many plant viruses that have the filamentous, rod-shaped, spherical, geminate and bacilliform morphology were observed in negatively stained preparations and in ultrathin sections, respectively. Their physicochemical and serological properties were characerized in purified virus preparations from infected plants. It was also examined the introduction of virus genes for plant protoplasts, preparation of monoclonal antibodies, and cloning - sequencing of viral genomes in some viruses. Viroids, a pathogen of free-RNA, were screened mainly in Rosaceae. The viroid- like RNAs were detected in pear, peach, rose, apple, and also carnation. The physicochemical and molecular properties of 22 and 3 species of undescribed viruses and plasmid-lik
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e DNAs, respectively, detected in plant pathogenic fungi, were also investigated. (2) The ultrastructures and constituted components such as polypeptides and nucleic acids were analized on nuclear polyhedrosis, cytoplasmic polyhedrosis, pox, densonucleosis and infectious flacheria viruses in silkworm and agro-insects. It was also examined the establishment of cell culture systems, screening of antiviral substances, genetics of virus resistance and habitual host of wild insects. (3) Adeno, herpes, calici, prarmyxo, corona viruses containing DNA or RNA in caline, feline, horse, chicken, were purified from cell culturs and organs. The ultrastructures, physicochemical properties and antigenicity were examined in these viruses. It was also tested the procedures for detection and/or titration, and vaccination of them. (4) Nitrogen fixation genes of Klebsiella oxytoca, a important nitrogen fixation bacterium in rhizosphere of root nudules of rice plants, were cloned and sequenced, and also reconstructed for the improvement of their ability. Base sequence and properties of cellulase genes of Bacillus subtilis were proved, and these natures were compared with Streptomyces celulase. The aspartic protease gene of mucor rennin was expressed by recombinant yeast cells. Less
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