Silk is praised "Queen of Fiber", which wrote a glorious page in the history of human adornment culture. Thanks to the development of science and technology, silk production has been increased dramatically during last half century. Nowadays, as "Healthy Fiber" silk lets all the globe to be forming the "Silk Boom" Like in other scientific fields, a great deal of progress has been made in sericultural science and technology, which also accelerated the development of multipurpose utilization of sercultural recourses. The main tendency of the sericulture development is raising the quality of cocoon, and at the same time, increasing the output per unit mulberry area and labor production efficiency. The chief measure of raising the cocoon quality is breeding and selecting the new mulberry and silkworm varieties, preventing and curing the diseases and pests and improving the environment of mounting, and the symble for increasing the labor productivity is carrying out the technological system of saving labor and operation ease, and enlarging the production scale. As a natural protein fiber, silk will be still a favorite with human in the next century, because its structure and properties can not be replaced by other any fiber. The 21st century is the biological time, and measures of developing sericulture will use the achievement on the field of molecular biology and biotechnology to carry out the molecular breeding, development regulating, silkworm rearing industrializing, exploiting the new silk and its new usage, utilizing the sericultural resources, and producing the special protein from silkworm as a host of expressing exogenous genes so that make the sericulture to contribute more what it can do for the human being.

This is a progress report of rice biotechnology including development of gene transformation system, gene cloning and molecular mapping in rice. The scope of the research was focused on the connection between conventional breeding and biotech-researches. Plant transformation via Agrobacterium or particle bombardment was developed to introduce one or several genes to recommended rice cultivars. Two chimeric genes containing a maize ribosome inactivating protein gene (RIP) and a gerbicide resistant gene (bar) were introduced to Nipponbare, a Japonica cultivar, and transmitted to Korean cultivars. The homozygous progenies of herbicide resistant transgenic plant showed good fertility and agronomic characters. To explore the genetic resourses in rice, over 8,000 cDNA clones from immature rice seed have been isolated and sequenced. About 13% of clones were identified as enzymes related to metabolic pathway. Among them, twenty clones have high homology with genes encoding enzymes in the photorespiratory carbon cycle reaction. Up to now about 100 clones were fully sequenced and registered at EMBL and GenBank. For the mapping of quantitative tarits loci (QTL) and eternal recombinant inbred population with 164 F13 lines (MGRI) was developed from a cross between Milyang 23 and Gihobyeo, Korean rice cultivars. After construction of fully saturated RFLP and AFLP map, quantitative traits using MGRI population were analyzed and integrated into the molecular map. Eighty seven loci were determined with 27 QTL characters including yield and yield components on rice chromosomes. Map based cloning was also tried to isolate semi-dwarf (sd-1) gene in rice. A DNA probe, RG 109, the most tightly linked to sd-1 gene was used to screen from bacterial artifical chromosome (BAC) libraries and five over lapping clones presumably containing sd-1 gene were isolated. Rice genetic database including results of biotech reasearch and classical genetics is provided at Korea Rice Genome Server which is accessible with world wide web (www) browser. The server provides rice cDNA sequences and map informations linked with phenotypic images.

Diapause hormone (DH) is a neuropeptide hormone which is secreted from the suboesophageal ganglion (SG) and is responsible for induction of embryonic diapause of the silkworm, Bombyx mori. DH is isolated from SGs and determined to be a 24 amino acid peptide amide. The cDNA encodes the polyprotein precursor from which DH, pheromone biosynthesis activating neuropeptide (PBAN) and three other neuropeptides are released and become matured. The C-terminal FXPRL-NH2 sequence of DH is essential but not sufficient for expression of full activity. Recently, we have isolated a unique hydrohobic peptide (VAP peptide) with a slight diapause egg induceing activity from organic solvent extracts of the male adult heads of the silkworm. The VAP peptide itself has no diapause inducing activity, but enhances DH activity through reducing ED50 value and the threshold concentration of DH. The DH-PBAN gene is composed of 6 exons interrupted by 5 introns and is expressed in 12 neurosecretory cells of the SG. The incubation of eggs at 25$^{\circ}C$, which induces embryonic diapause in the progeny, caused DH-PBAN mRNA content to increase at 5 different stages in the life cycle. By contrast, a 15$^{\circ}C$ incubation only induced expression of the gene at the late phrase adult stage. The temperature-controlled expression of DH-PBAN gene is closely correlated to the incidence of diapause, indicating that DH-PBAN gene expression is the initial event leading to diapause induction. DH acts to stimulate trehalase activity in developing ovary to bring about hyprglycogenism in mature eggs, a prerequisite metabolism for diapause initiation. Using in vivo and in vitro systems, DH is clearly shown to induce trehalase gene expression in developing ovaries. New protein synthesis is not needed for this process, but a Ca2+-dependent proteinkinase seems to be involved. Quite recently, we have sucessfully applied a new and potent trehalase inhibitor (Trehazoline) to reudce glycogen content in developing ovaries. The eggs deficient in glycogen were also able to enter diapause as the natural eggs do, so that we could provide the new egg system to reconsider the diapause associated metabolism other than the glycogen-sorbitol metabolic system.

Baculoviruses are characterized by large double-stranded circular DNA genomes and rod-shaped enveloped virions. Bombyx mori nucleopolyhedrovirus(BmNPV) is a major pathogen, which causes severe damage in sericulture. Currently, BmNPV is recogtnized as an improtant tool in molecular biology, especially for expression of useful genes in B.mori cells and silkworm larvae. Our laboratories have focused on the studies of the molecular mechanisms of BmNPV replication and the application of BmNPV to agriculture and medicine. The entire nucleotide sequence of the BmNPV genome has recently determined. The BmNPV genome possessed 135 putative genes and 7 homologous repeated sequence (hrs) regions. Relatively little space, a few to a few hundred base-pairs, was observed between the open reading frames and hrs. Termination codons often overlapped. These results showed a compactly packde BmNPV genome. Based on comparative sequence analyses, we speculated that the ancestor of BmNPV was a baculovirus similar to Autographa californica NPV(AcNPV). The function of the BmNPV genes were characterized by gene deletion analysis; p35 was found to be involved in blocking apoptosis and cysteine proteinase was found to be involved in horizontal virus transmission by degrading viral-infected larval host. By AcNPV and BmNPV coinfection experiments, we identified a BmNPV gene involved in expanding host specificity of AcNPV. The identified gene was likely encoded a DNA helicase based on the amino acid sequence analysis; a few amino acid substitutions in the putative DNA helicase gene resulted in the expansion of host range of AcNPV. These findings indicate that BmNPV evolved within a short period from an AcNPV-like ancestral virus due to rapid evolution including specific amino acid substitutions and gene deletions/insertions.

Decrease in the cocoon production of Japan is drastic because of low price of cocoon, scarcity of successors and so on. To tide over the difficulty, the automation system in the sericulture was discussed and some trials have been conducted by the Ministry of Agriculture, Forestry and Fisheries of Japan. The attempts are based on a low cost artificial diet which does not rely on mulberry leaves. Automatic machines developed until now are a rearing machine constituted with repeated belt conveyor, an reformation type of former rearing machine "Bombyx" and a mounting machine. Running parallel with them, utilization of 20-hydroxyecdysone extracted from a plant to the mounting was also studied to use their machines efficiently in the fields. In conclusion, 10 tons of law cocoon will come to be produced by two persons labor. At present, an automatic rearing system on low cost artificial diet has been developing for the future sericulture.

As the average span of human life is continuously increasing, especially the old aged groups, are suffering from various chronic and critical diseases e.g. cardiovascular diseases, coronary heart disease, diabetes, atherosclerosis and alzheimer's etc. However, effective and safe treatment methods have not yet been investigated threathening old aged groups. This research was planned to isolate compounds with the therapeutic potential for the above mentioned chronic diseases from the mulberry leaves. Biological screenings were carried out for the following categories; anti-atherogenic, anti-diabetic and antihypertensive effects. The results were as follows; Mulberry leaves, 20% $\alpha$-treated Gaelyrangppong showed significant 81% of blood glucose lowering effects in alloxan-induced hyperglycemic mice. Particularly, butanol-soluble fractions of mulberry leaves showed the more significant hypoglycemic activity than other fractions in alloxan induced hyperhlycemic mice. Also in the group given 1g/kg doses of extract of mulberry leaves, total cholesterol level was decreased significantly by as much as 49% in hyperlipidemia-induced rats. In Mulberry leaves post-treated group, the atheroscelosis index, HDL-cholesterol/Total-cholesterol, was increased significantly by as much as 91%.

Since 1992, Sericulture & Entomology Research Institute(NSERI) and Kyung Hee University group screened an activity of lowering blood-glucose levels with silkworm related materials such as silkworm larvae powder, dried feces, pupae and silkworm moth in other to guide laymans to rational and educated utilization of silkworm-related materials for the treatment of diabetes mellitus. In experiments examining several silkworms in different stages and prepared in different conditions, a freeze dried silkworm powder of 5th instar 3rd day showed a higher glucose lowering activity about 20% than heat dried matured silkworm powder. Among the three dosage of 500mg, 830mg and 1,160mg in ate preliminary clinical trial, the 830mg exhibited a significant effect on postprandial blood glucose level and did and did not cause any hypoglycemic side effect. In the blood glucose lowering activity of mulberry and silkworm varieties, the Yongcheonppong and Samkwangjam showed the highest activity for lowering blood glucose levels. In experiments to see the difference in blood-glucose lowering activity between either male and female or larvae and pupae, activity of larvae was higher than that of pupae and the male was higher than female. The heating dry and artificial diet showed lower than mulberry diet and normal freeze dry of the 5th instar 3rd day. Among the sericultural products, larvae showed the highest activity. We find out the fact that effect of silkworm powder attributed to the inhibition of ${\alpha}$-glucohydrolase catalyzed reaction in the small intestine.

ABA-type(or AB) block copolymers composed of poly(${\gamma}$-alkyl L-glutamate) (PALG)[or poly(L-leucine)] as the A component and polyether[or poly (N-isopropy1 acrylamide) as the B component were synthesized by polymerization of (${\gamma}$-alkyl L-glutamate N-carboxyanhydride initiated by primary amined located at both(or one) ends of the polymer chains. Structural studies of the block copolymers were performed in the solution and solid state. Also, artificial skin, drug delivery system of the block copolymers and cell attachment onto the copolymer were carried out for biomedical applications.