Earthworms, especially Eisenia andrei, are cultivated for a variety of purposes including waste disposal and compost production. In this study, bacteria from earthworm gut were cultured and the dominant species identified. Subsequently, we isolated bacteriophages able to lyse the isolated gut bacteria. Two dominant genera of gut bacteria, Aeromonas sp. and Citrobacter sp. were identified by using MALDI-TOF MS analysis and a library was constructed to find lytic phages. Phage EF1 showed lytic activity for C. freundii and two Citrobacter isolates, C. braakii and C. murliniae. These 3 species have similar sensitivities to EF1. Several aspects of the life cycle of EF1 were investigated by using C. freundii under optimal growth conditions. EF1 infects C. freundii with a moderate latent period, approximately 25 min, and a large burst size averaging 5 × 109 per infected cell. Moreover, the antimicrobial activity of EF1 was well maintained under diverse conditions including a broad temperature range of 40°C to 50°C and a wide pH range of 4 to 11. In conclusion, the results indicate that earthworm casting contain a wide range of bacteria species, for which there are various corresponding bacteriophages.

The silkworm (Bombyx mori), as an industrial insect, possesses a high economic value. Casual discrimination and accumulated genetic information of silkworm varieties are essential ground for the practical utilization and long-term conservation. In this study, nine available microsatellite loci were successfully genotyped from ~50 silkworm strains preserved in Korea. According to genotyping analysis, we obtained 3 ~ 16 alleles per locus, with an average of 7.4, the observed heterozygosity ranging from 0.04 to 0.98, and the polymorphic information content (PIC) ranging from 0.06 to 0.88, revealing that some loci are highly variable. Among 54 strains 13 strains were casually identified by the presence of 17 strain-specific apomorphic alleles. Furthermore, 30 among remaining strains contained strain-specific allele combinations that are also apomorphic to each strain, allowing us to discriminate each of these from other strains by genotyping of multiple loci. These results collectively suggest that the silkworm microsatellite DNA is actually and potentially important molecular marker for the discrimination of the silkworm strains that are preserved as hundreds in Korea, as more loci are genotyped.

Three acetylcholinesterases (AChEs) were identified from the pinewood nematode, Bursaphelenchus xylophilus. Sequence comparison with known AChEs in conjunction with three-dimensional structure analysis suggested that all BxAChEs share typical characteristics of AChE at the major catalytic structures. BgAChE3 was most predominantly transcribed and then followed by AChE1 and AChE2. Immunohistochemistry using anti-BxAChEs antibodies revealed that BxAChE1 is most widely distributed whereas BxAChE2 exhibits more localized distribution in neuronal tissues. BxAChE3 was detected from entire body together with some limited tissues, including mouth parts and alimentary lining, and determined to be the only soluble AChE, suggesting its localization in hemolymph or/and extracellular space. Kinetic analysis of in vitro expressed BxAChEs revealed that BxAChE1 has the highest substrate specificity whereas BxAChE2 has the highest catalytic efficiency with BxAChE3 having the lowest catalytic efficiency. Interestingly, presence of BxAChE3 in the pool of BxAChEs significantly reduced the inhibition of BxAChE1 and BxAChE2 by inhibitors. Knockout of BxAChE3 by RNAi significantly increased the toxicity of nematicides, suggesting the protective role of BxAChE3 against these toxicants. Based on several features, including tissue distribution, expression level, substrate kinetics and inhibition property, it appeared that BxAChE1 is the major AChE with the function of postsynaptic transmission whereas BxAChE3 has been evolved to acquire the function of chemical defense, perhaps intrinsically against secondary toxic compounds from host pine trees, such as α-pinene and limonene. BxAChE2 appears to play a role in post-synaptic transmission in specialized neurons but its detailed physiological function still remains to be elucidated.

졸-겔 공정은 비교적 간단하고 사용이 편리하며 저렴한 설비투자비가 소요되면서도 우수한 물성 및 차단특성을 갖는 코팅 박막을 얻을 수 있다는 장점이 있다. 졸-겔 공정으로 코팅된 필름은 산소 등의 영향에 의해 부패되기 쉬운 식품, 음료, 약품, 의약품 등의 포장재나 단열제로 응용 가능하다. 본 연구에서는 aluminum isopropoxide를 출발물질로 하여 alumina sol을 제조한 후 실란 커플링제를 첨가하여 코팅 용액을 제조하였다. 또한, 제조된 alumina sol 용액을 이축연신 폴리프로필렌(BOPP)에 코팅하여 복합 필름을 만들고 산소 투과 특성을 측정한 결과 순수한 BOPP에 비해서 산소 투과도가 약 85% 정도 감소되는 효과를 보였다.

Mutagenesis approach in combination with whole genome sequencing has become an import role in genetic and molecular biological study and breeding of crop plants. In this study, we screened the fast neutron M4 10,000 soybean mutant plants based on morphological phenotypes of agronomically important traits and characterized the mutant of interest using resequencing. Fast neutron radiation has been known to be a very effective mutagen to cause large deletion in genome. The screened mutant showed abnormal phenotypes in plant heights, seed sizes, color of leaves, number of leaves, maturity and number of branches etc. Among them, the mutant displaying short plant height and bush type of growth habit was selected for identification of the altered genomic regions. Analysis of deletion sites of genome in interesting soybean mutant was performed using next generation sequencer Illumina Hi-seq. Mutant sequence reads generated by paired-end shotgun library were mapped on a draft soybean reference soybean (G. max cv. Williams 82). The paired-end DNA sequences of 21.6 Gb produced by Illumina Hi-seq produced 21 fold sequence depth. Among the predicted deletion sites, total 3 deletion regions confirmed by PCR. Glyma03g02390 gene and Glyma03g03560 gene were involved in the deletion regions. Glyma03g02390 gene was related to AMP binding, catalytic activity, cofactor binding and metabolic process of cell growth and Glyma03g03560 gene was concerned to oxygen binding, defense response to bacterium, and especially process of indole acetic acid (IAA) biosynthesis. These genes detected in this mutant will be studied about their molecular function in stunted phenotype.

“Ilyeop” (Perilla frutescens (L.) Britton), a new cultivar for leaf vegetable, was developed from a cross between Ipdeulkkae1 and YCPL187 at the National Yeongnam Agricultural Experiment Station, RDA, in 2001. For the cultivation of leaf vegetable perilla, the plants are grown with a spacing of 10 × 5 cm between rows and plants and all branches are removed to harvest uniform leaves from main stem, indicating that the amount of the next harvesting leaf is a important characteristic for the growth of the plant. “Ilyeop” grows vigorously and yields high quality leaf with higher amount of the next harvesting leaves composed with a check cultivar, “Ipdeulkkae1”. “Ilyeop” has five days of earlier seed maturity (Oct. 24) than that of “Ipdeulkkae1” under natural condition, less chance of frost damage is expected. The flowering date of “Ilyeop” is same with that of “Ipdeulkkae1” in winter cultivation with night break treatment.

“Bora” is a new perilla (Perilla frutescens (L.) Britton) cultivar developed from a cross between Ipdeulkkae1 and YCPL199 at National Yeongnam Agricultural Experiment Station, RDA, in 2001. Purple backside leaf color is one of the most important characteristics for the high quality perilla leaf. “Bora” has purple backside leaf color in all climate condition, while a check variety, Ipdeulkkae1 has too light color during summer season or in high temperature condition. “Bora” matures at October 18th and has 79 cm of the stem length, shorter than that of Ipdeulkkae1. Although leaf yield is 11% less than that of a check variety Ipdeulkkae1, the harvested leaf number of “Bora” is similar with that of Ipdeulkkae1. The cultivar is appropriable in all area of Korea for the leaf harvesting cultivation whereas it is restricted to southern part of Korea South Gyeongsang and South Jeola provinces, for the seed harvesting cultivation.