Acquisition of a reference Tetranychusstrains that are completely susceptible to acaricides and retain identical genetic backgrounds to acaricide-resistant strains is an essential step in elucidating mechanisms of resistance. To establish both completely susceptible and acaricide-resistant strains for this purpose, I collected Tetranychus mite populations from various regions in South Korea including both heavily cultivated and remote regions. Suitability as a susceptible or resistant reference strain was tested by determining species identity as Tetranychus urticae along with baseline susceptibility to common acaricides. The majority of mite populations collected from cultivated areas belonged to a monophyletic group of the previously reported green-type T. urticae as determined by mtCOI- and ITS2-based phylogenetic analysis. These strains showed relatively reduced levels of susceptibility to the acaricides tested, suggestive of the development of resistance. Among them, the AbaR strain was classified as a minor group in the T. urticae complex. The UD strain, originally collected from a remote island region, was found to be susceptible to the acaricides tested and generated an independent phylogenetic branch. The UD strain was also considered a minor group in the T. urticae complex. Phenotypic analysis based on morphological characters confirmed that both the AbaR and UD strains were statistically undistinguishable from the major green-type T. urticae. Taken together, I propose that the UD strain be used as a susceptible reference strain as it provides baseline susceptibility to acaricides and a wild-type genetic background for the resistance studies.

To search for hyper-variable genetic markers that can distinguish regional populations of head lice, we screened the inter simple sequence repeats (ISSR) based on the genome database of body louse, which is closely related conspecific species. An ISSR mining software, SciRoKo 3.4, was employed to excavate ISSR markers from the genome database under the MISA mode (≥ 60 bp repeats). Entire body louse genome (ca.100 Mb) was loaded to SciRoKo for ISSRs mining. A total of 5,336 ISSRs were obtained, and primers specific to individual ISSRs were designed by the Primer 3 and DesignPrimer 1.0 softwares. In order to prove the compatibility of body louse ISSRs to head lice, 31 PCR primers were randomly chosen out of a total of 613 pairs, and their appropriateness was tested by comparing the amplified PCR band patterns between body and head lice. Eleven primer pairs that resulted in poor or little amplification were excluded, and 20 primer pairs were further tested for three head louse populations (California, Panama and Chung-ju, Korea). Finally, nine primer pairs ensuring robust amplification of highly variable band patterns were selected to use for population genetic study of head lice.

This study was conducted to clear the regional difference in the resistance development of the spirodiclofen 36% WP, an acaricide of tetronic acid class, against two-spotted spider mite, Tetranychus urticae occurred in apple orchard since 2007. Two-spotted spider mite was collected from eight regions in the Chungnam, Chungbuk and Gyeongbuk that were major apple cultivation in Korea. An bioassay was investigated the ovicidal activity to compare with the degree of resistance development of this pest. The managed orchard in Sancheok-myeon, Myeongseo-ri, Chungju was controlled by several different acaricides from 2001 to 2008, and spirodiclofen WP was used for the last seven years. LC50 of spirodiclofen WP was estimated as 19.4 ppm in managed orchard, it showed as high as 2.6-fold (resistance ratio) comparing to those of susceptible strain showed as 7.5 ppm. LC50 of spirodiclofen WP against etoxazole-resistant two-spotted spider mite, gained from Chungbuk National University, was proved in 8.1 ppm. This observation indicates that spirodiclofen WP did not occurred in cross resistance with etoxazole SC. Other two regions in Chungju, the resistance ratio against spirodiclofen WP showed as 2.5- and 2.3-fold, respectively. In Chungnam, Gyeongbuk, it has been limited the resistance ratio under 3-fold, respectively.

The TSSM is one of the most destructive pests on various orchard trees and garden plants. Abamectin resistance mechanisms in two resistant TSSM strains (PTF, ca. 155-fold; AbaR, ca. 3700-fold) were investigated with an emphasis on target site insensitivity mechanism. Detoxification enzyme assays revealed that metabolic factors contributed by EST and/or P450are involved in abamectin resistance. Synergistic assays showed that enhanced detoxification enzyme activity is not enough to account for the high level of abamectin resistance, further suggestive of the involvement of additional resistance mechanism, most likely target site insensitivity. As a putative target site for abamectin, we cloned the cDNA fragments of glutamate-gated chloride channel (Tuglucl) and determined its full length nucleotide sequences. Amino acid sequence comparison among the four strains showed that the Gly323Asp mutation located in the third transmembrane domainis only found in the AbaR strain, suggesting it is likely associated with the target site insensitivity conferring a high level of abamectin resistance.

An outbreak of Ussur Brown Katydid, Paratlanticus ussuriensis, occurred in the orchard areas of central Korea during 2006 and 2007. These crickets occur widely in Korea but before 2000 they were not regarded as an agricultural pest and were mainly confined to wooded hillsides. In an attempt to understand this katydid ecology, firstly, we have conducted a life cycle study of the Ussur brown katydid. This katydid spends one or two years as an egg stage. Most of eggs enter the initial diapause, which take place in stage 4. Less than 10% eggs didn't occur the initial diapause and developed until in stage 23 before beginning winter season. In the laboratory experiment, diapause depends on the initial temperature after eggs laid. They had an initial and final diapause around less 25℃. Therefore, it takes two years to hatch at low temperature. On the other hand, eggs are kept at temperatures around over 27℃, entry into the first diapause stage was circumvented and eggs emerged the following spring. That is, the high temperature seems to affect on the life cycle of Katydid. Thus, if they are exposed to high temperature on early egg stage, they emerge next year just after spending a winter.

A new species of Adoxophyes unique from other closely resembling species was discovered based on molecular characters. Larvae of this species were collected from sweet cherry (Prunus avium) imported from China and intercepted under plant quarantine inspection at Korean sea and airport in 2008. They were reared to adult in the laboratory for accurate identification. We also collected two specimens from China for this study. In addition, we conducted a comparative study of three related Korean species (A. orana, A. honmai, and A. paraorana (= orana-like)) to confirm the identity of new species. We compared DNA barcoding sequences (~658 bp) of the mitochondrial cytochrome c oxidase subunit I (COI) gene from 13 specimens of four Adoxophyes species. We also compared variable internal transcribed space region 1 (ITS 1) nuclear rDNA sequence for further identification. As a result of this study, we confirmed the identity of Adoxophyes a new species. We also provided pairwise p-distances among the species and their neighbor-joining tree.

This study was conducted to develop a model for describing the effect of storage temperature (4, 10, 15, 20, 25, 30 and 35℃) on the growth of Escherichia coli O157 : H7 in ready-to-eat (RTE) lettuce treated with or without (control) alkaline electrolyzed water (AIEW). The growth curves were well fitted with the Gompertz equation, which was used to determine the specific growth rate (SGR) and lag time (LT) of E. coli O157 : H7 (R2 = 0.994). Results showed that the obtained SGR and LT were dependent on the storage temperature. The growth rate increased with increasing temperature from 4 to 35℃. The square root models were used to evaluate the effect of storage temperature on the growth of E. coli O157 : H7 in lettuce samples treated without or with AIEW. The coefficient of determination (R2), adjusted determination coefficient (R2 Adj), and mean square error (MSE) were employed to validate the established models. It showed that R2 and R2 Adj were close to 1 (> 0.93), and MSE calculated from models of untreated and treated lettuce were 0.031 and 0.025, respectively. The results demonstrated that the overall predictions of the growth of E. coli O157 : H7 agreed with the observed data.

The study was conducted to evaluate the effect of drying, curing and freezing on the quality of beef. Three types of dried (without salt = T1, with salt = T2 and salt + spices = T3); three types of cured (salt curing = T4, sugar curing = T5 and brine curing = T6) and three types of frozen beef (0℃ = T7, -10℃ = T8 and -20℃ = T9) were analyzed at different time intervals up to the period of 180 d. Parameters studied were protein, fat, ash, color and cooking loss of beef. All the chemical constituents (protein, fat and ash) were decreased gradually up to 120 d. The decreasing trend was observed rapid after 120 d up to 180 d of preservation. Highest protein loss was found in T7 (11.1%) and the lowest protein loss was found in T6 (3.85%) in 180 d preservation and significant (p < 0.01) differences were observed among the different preservation methods. Highest fat loss was observed in T6 (7.62%) and the lowest fat loss was observed in T2 (3.18%) and the differences were also significant (p < 0.05) among different methods during the experimental period. Spices dried beef showed a brighter color than others and cured beef showed brown color and the intensity of color was reduced gradually with the increasing of storage period. T9 showed the lowest cooking loss among 3 treatments of frozen beef and the differences also significant (p < 0.01) up to 180 d. It might be stated that sugar curing (T5) and spices drying (T3) would be the useful technique of meat preservation in rural areas and freezing (T9) would be used in large scale preservation at urban areas.

The importance of nanopore structures of carbons is shown in terms of interaction potential for various molecules including supercritical gases such as H2 and CH4. The key factors for adsorption of supercritical H2 and CH4 are shown for single wall carbon nanohorn, single wall carbon nanotube, and double wall carbon nanotube. The cluster formation of molecules is a key process for water adsorption on hydrophobic carbon nanopores. The X-ray absorption spectroscopic examination elucidates an explicit dehydration structure of ions confined in carbon nanopores.

EBR-II사용후핵연료의 파이로건식처리공정에 의해 발생된 우라늄의 순도에 대한 포괄적인 분석을 수행하였다. 분석결과를 미국 아이다호 국립연구소 및 한국원자력연구원의 협력과제 하에서 한국과 미국의 저준위 폐기물 기준으로 비교하였다. 미국의 저준위 폐기물 기준은 우라늄 동위원소를 포함하지 않으나, 한국의 경우는 포함하는 것으로 조사되었다. 분석결과 EBR-II 우라늄 생성물 내에서 저준위 기준을 초과하는 유일한 알파 핵종은 우라늄 동위원소가 아니라 Pu-239였다. 생성물 내의 Pu 오염은 개량된 염증류공정을 통한 예비실험 결과 획기적으로 줄일 수 있음을 알 수 있었으며, 보다 공정을 개선 시킨다면 제안된 기술을 이용하여 미국의 저준위 기준을 만족시킬 수 있을 것으로 판단된다

In this paper, statistical distribution functions are developed for distance determination of stellar groups. This method depends on the assumption that absolute magnitudes and apparent magnitudes follow a Gaussian distribution function. Due to the limits of the integrands of the frequency function of apparent and absolute magnitudes, we introduce Case A, B, and C Gaussian distributions. The developed approaches have been implemented to determine distances to some clusters and stellar associations. The comparison with the distances derived by different authors reveals good agreement.

Ingestion of plant secondary metabolites (PSMs) presents a major challenge to mammalian herbivores. We investigated the relationship between PSM concentrations in the diet and feeding patterns in sheep fed diet containing flavone extracted from Apocynum venetum. Results showed that the flavone concentrations significantly influenced food intake by sheep. With the concentration of flavone in diet increase, sheep can regulate their intake of PSM within limits that are tolerable.

Grazing restoration succession of the degraded grassland is an important aspect in community ecology. Field experiment was carried out to examine how major species restore in first four years restoration following 11 consecutive grazing under different stocking rates in Inner Mongolian steppe. A. frigida and P. acaulis are the most important two species in the all treatments (NG, LG, MG and HG) after four years restoration, although they had high fluctuation. The biomasses of these two species account for 40-90% of total biomass. Especially in no grazing area, which was exclosured since 1990, A. frigida and P. acaulis are still the most important two species in the community. These results suggested A. frigida and P. acaulis conununity are quite stable, and will keep long-time if no special measurements were taken during the restoration of the degraded grassland.

To explore the relationship of species diversity and aboveground productivity in grazing ecosystem is very important to manage grassland. We used the four years' data to check this relationship and to look how abiotic factor affect species diversity and aboveground productivity. We found a good linear relationship between species diversity and aboveground productivity in all previous grazing sites, while no any relationship was found in the no grazing site. From our results, we concluded that drought affects aboveground productivity more than grazing, while heavy grazing affects species diversity more than drought in Inner Mongolian steppe.