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        41.
        2013.04 구독 인증기관·개인회원 무료
        The bumblebee, Bombus ignitus (Hymenoptera: Apidae), is a valuable natural resource that is widely utilized for greenhouse pollination in South Korea. Understanding the magnitude of genetic diversity and geographic relationships is of fundamental importance for long term preservation and utilization. As a first step, we sequenced a partial COI gene of mitochondrial DNA (mtDNA) corresponding to the “DNA barcode” region and the complete internal transcribed spacer 2 (ITS2) of nuclear ribosomal DNA from 88 individuals collected in nine South Korean localities. The complete ITS2 sequences were longest among known insects, ranging in size from 2,034 bp ~ 2,052 bp, harboring two duplicated 112-bp long repeats. The 658-bp long mtDNA sequences provided only six haplotypes with a maximum sequence divergence of 0.61% (4 bp), whereas the ITS sequences provided 84 sequence types with a maximum sequence divergence of 1.02% (21 sites). The combination of the current COI data with those of published data suggest that the B. ignitus in South Korea and China are genetically a large group, but those in Japan can be roughly separated into another group. Overall, a very high per generation migration ratio, a very low level of genetic fixation, and no discernable hierarchical population were found to exist among the South Korean populations of B. ignitus, which suggests panmixia. This finding is consistent with our understanding of the dispersal capability of the species.
        43.
        2012.09 구독 인증기관 무료, 개인회원 유료
        The previous studies of p16INK4a, pRb, p53, and Ki-67 expression suggested that these markers may be preferentially expressed in cervical neoplasms. The purpose of this study was to assess the expression and the clinical significance of p16INK4a, pRb, p53, and Ki-67 proteins in cervical lesions. We obtained 106 cases with various categories of cervical squamous mucosa, including squamous cell carcinoma (n=35), cervical intraepithelial neoplasia (CIN) II/III (n=26), CIN I (n=10), squamous metaplasia (n=15), and normal squamous mucosa (n=20). Immunohistochemical staining was performed for p16INK4a, pRb, p53, and Ki-67 proteins in formalin-fixed and paraffin-embedded tissue sections of the uterine cervix. Evaluation of immunohistochemical staining was based on the frequencies of expression and the mean immunoreactivity scores (IS) in each diagnostic category. p16INK4a positive sotaining was observed in 26 of 35 cases (74.3%) of squamous cell carcinoma, in 16 of 26 cases (61.5%) of CIN II/III, in six of 10 cases (60%) of CIN I, in nine of 15 cases (60%) of squamous metaplasia, and negative in normal squamous mucosa. pRb expression was detected in all diagnostic categories; however, the proportion of pRb positive cells was relatively decreased in CIN II/III (38.5%) and squamous cell carcinomas (51.4%), compared to normal squamous epithelium (90%) and squamous metaplasia (73.3%). No significant differences in expression of p53 were observed in any diagnostic categories. Ki-67 expression was increased in squamous cell carcinoma (37.1%), CIN II/ III (42.3%), and CIN I (40%), but negative in squamous metaplasia and normal mucosa. In 35 cases of squamous cell carcinomas, multivariate analysis revealed no differences in pINK4a, pRb, p53, and Ki-67 expression according to the age of the patient, lymph node metastasis and clinical stage. In conclusion, the combined use of p16INK4a and Ki-67 immunoreactivity could improve the diagnostic specificity of squamous cell carcinoma of the uterine cervix.
        4,000원
        44.
        2012.06 구독 인증기관·개인회원 무료
        MAC-T cells, bovine mammary epithelial cell line, have been utilized to investigate bovine lactation system. A lactogenic phenotype of the cell is generally induced by combination of dexamethasone, insulin and prolactin (PRL). Effect of vitamin A derivative retinoic acid (RA), well reported as an inducer for differentiation in many cells, to MAC-T cell has not been studied. The objective of this study was to confirm effect of differentiation potential by RA treatment in MAC-T cells and to test effect of combination of RA and PRL treatment. In RA or PRL treatment groups, both has induced morphological change to secrete milk of MAC-T cells. Combination of RA and PRL treatment group has presented noticeable lactogenic phenotype among the all group. This phenotype observed at four days after treatment and showed critical morphological change that was rouphly spherical structure at eight days. RA alone treatment showed slightly inhibition of proliferation in the MAC-T cells, but co-treatment with PRL was improved the cell growth more than control group. MTT assay result and Bcl-xL/Bax ratio of mRNA abundance also was entirely consistent with earlier one. RA-induced differentiation of MAC-T cells has increased αs1-casein, αs2-casein and β-casein mRNA expression compared to PRL treatment group. Expression of αs1-casein, αs2-casein and β-casein genes represented the maximum value in the combination of RA and PRL treatment group at four days. The value of each casein gene expression was 4-, 5.5- and 5.9-fold, respectively, as compared with PRL alone treatment in the MAC-T cells. Protein level of β-casein releasing to the medium also induced the highest level at four days. These results provide evidence that RA can induce the differentiation of MAC-T cells and have synergetic effect with PRL.
        45.
        2011.03 구독 인증기관 무료, 개인회원 유료
        Ursolic acid is a triterpenoid compound present in many plants. This study examined the antimicrobial activity of ursolic acid against mutans streptococci (MS) isolated from the Korean population. The antimicrobial activity was evaluated by the minimum inhibitory concentration (MIC) and time kill curves of MS. The cytotoxicity of ursolic acid against KB cells was tested using an MTT assay. The MIC90 values of ursolic acid for Streptococcus mutans and Streptococcus sobrinus isolated from the Korean population were 2 μg/ml and 4 μg/ml, respectively. Ursolic acid had a bactericidal effect on S. mutans ATCC 25175 T and S. sobrinus ATCC 33478 T at > 2 × MIC (4 μg/ml) and 4 × MIC (8 μg/ml), respectively. Ursolic acid had no cytotoxic effect on KB cells at concentrations at which it exerted antimicrobial effects. The results suggest that ursolic acid can be used in the development of oral hygiene products for the prevention of dental caries.
        4,000원
        46.
        2010.12 KCI 등재 구독 인증기관·개인회원 무료
        Neurotrophic factors are essential to maintain and organize neurons functionally; thereby neurotrophic factor-like substances or their inducers are expected to be applied to the treatment of neurodegenerative diseases such as stroke. In the present study, we firstly examined the effects of ethanol extracts of Hericium erinaceus (HE, Yamabushitake), on nerve growth factor expression in neuronal cells. HE extract promoted NGF expression in a brain tissue. Here we assessed neuroprotective effects of HE with a transient global cerebral ischemia model. Global cerebral ischemia was induced by occluding both common carotid arteries. Treatment with HE was initiated after ischemia induction and given once a day for 7 consecutive days. Neuronal cell loss in CA1 of hippocampus was significantly decreased and the performance in the Morris water maze was significantly improved in rats administered HE. We conclude that treatment with HE attenuated learning and memory deficits, motor functional disability, and neuronal cell loss induced by global cerebral ischemia. These results suggest that HE may be a potential candidate for the treatment of vascular dementia.
        48.
        2010.05 구독 인증기관·개인회원 무료
        The perilla leaf pyralid moth, Pyrausta panopealis Walker (Lepidoptera: Pyralidae), is a serious pest damaging to leaf perilla. In order to establish the life parameters of P. panopealis for eventual purpose of control, the developmental span of each stage were investigated under five temperature regimes (20℃ ~ 3 0℃). In addition, the larvicial efficacy of several on-the-market environment-friendly agricultural materials (EFAMs) was tested. The width of head capsule at each larval stage measured to be the mean of 0.21, 0.32, 0.47, 0.64, and 0.98 mm, respectively. The larval period of P. panopealis was longest at 20ºC as 27.0 days and shortened as temperature goes up to 30ºC as 11.3 days. Survivorship of the larval P. panopealis was the highest at 30ºC as 80%, whereas that of other temperatures ranged from 40% (20ºC) to 62.5% (27.5ºC), indicating that the P. panopealis appears to favor higher temperature. In addition to larval period, the duration of egg, prepupa, and pupa stages also shortened as temperature goes up, whereas the duration of adult stage increased as temperature goes up: from 4.1 days at 20 ºC to 6.1 days at 30ºC. After the perilla leaf pyralid moths were successfully stabilized in indoor environment the larvicidal efficacy of the ten EFAMs that were previously selected from the result of other moth species was tested aimed at 4th instar larvae for 48 hrs. Seven of the ten tested showed more than 90% of mortality within 12 hrs and reached nearly up to 100% within 24 hrs, but the remaining three showed less than ~70%.
        49.
        2010.05 구독 인증기관·개인회원 무료
        The bumblebee, Bombus ignitus (Hymenoptera: Apidae), is a valuable natural resource that is one of the most notably utilized for greenhouse pollination in Korea. In order to understand the nature of genetic relationships, gene flow, and population structure of the species we sequenced a partial COI gene of mitochondrial DNA (mtDNA) corresponding to “animal barcode” region and the complete internal transcribed spacer 2 (ITS2) of the nuclear ribosomal DNA (nrDNA) collected from Korean localities. Although the 658-bp long mtDNA sequence provided only six haplotypes with the maximum sequence divergence of 0.61% (4 bp), the ITS sequences provided 84 sequence types with the maximum sequence divergence of 1.02% (21 sites), confirming better applicability of the ITS sequences to the study of intraspecific variation. The complete ITS2 sequences of B. ignitus were shown to be longest among known insects, ranging in size from 2,034 bp ~ 2,052 bp, harboring two duplicated repeats. Overall, a very high per generation migration ratio, a very low level of genetic fixation, and no discernable hierarchical population/ population group were noted to exist among populations of B. ignitus on the basis of both molecules, thus suggesting that the B. ignitus populations on the Korean peninsula are panmictic, which is consistent with our understanding of the dispersal capability of the species
        50.
        2009.10 구독 인증기관·개인회원 무료
        Diamondback moth (Plutella xylostella L.) belonging to genus Lepidoptera is a notorious pest of cruciferous crops worldwide. We evaluated the bioinsecticidal activity of the liquid cultures (LB and NB) of a bacterial strain, Serratia sp. EML-SE1, isolated from a diseased diamondback moth. The pathogenicity of a bacterial strain to diamondback moth was confirmed by the following procedures: treatment of liquid culture on cabbage leaves, ingestion of inoculated cabbage and mortality response. For the test, twenty 3rd instar larvae of diamondback moth were placed on the Chinese cabbage leaf in a round plastic cage (Ø 10 × 6 cm) and sprayed with the liquid cultures. After 72 hours, insecticidal activity of LB and NB cultures of Serratia sp. against P. xylostella larvae showed 91.7% and 88.3%, respectively. In addition, the bioinsecticidal activity on potted cabbage with 14 leaves in a growth cage (165 × 83 × 124 cm) also was similar to that of plastic cage experiment. Summarized, the Serratia sp. EML-SE1 may be a potent candidate as a bioinsecticidal agent to control diamondbac kmoth.
        51.
        2009.10 구독 인증기관·개인회원 무료
        The bumblebee, Bombus ignitus (Hymenoptera: Apidae), is a valuable natural resource that is one of the most notably utilized for greenhouse pollination in Korea. In order to understand the nature of genetic relationships, gene flow, and population structure of the species we sequenced a partial COI gene of mitochondrial DNA (mtDNA) corresponding to “animal barcode” region and the complete internal transcribed spacer 2 (ITS2) of the nuclear ribosomal DNA (nrDNA) with the individuals collected from Korean localities. Although the 658-bp long mtDNA sequence provided only six haplotypes with the maximum sequence divergence of 0.456% (3 bp, from 91 individuals), but the ITS sequences provided 33 sequence types with the maximum sequence divergence of 0.78% (16 bp, from 35 individuals), confirming better applicability of the ITS sequences to the study of intraspecific variation. The ITS2 sequences of B. ignitus were shown to be the longest among known insects, ranging in size from 2,034 bp ~ 2,045 bp and harbored two duplicated repeats, indicating unusual structure of B. ignitus ITS2 sequences compared with other insect ITS sequences. Overall, a very high per generation migration ratio, a very low level of genetic fixation, and no discernable hierarchical population/population group were noted to exist among populations of B. ignitus on the basis of both molecules, thus suggesting that the B. ignitus populations on the Korean peninsula are panmictic, which is consistent with our understanding of the dispersal capability.
        52.
        2009.08 구독 인증기관·개인회원 무료
        The main nutritional problem of sorghum×sudangrass (sudangrass) silage is low quality and dry matter (DM) contents. This experiment was conducted to evaluate whether agricultural byproducts addition of sorghum×sudangrass silage increases DM content and forage quality of the silage. Sorghum×sudangrass silage with added byproducts had low pH values, however sorghum×sudangrass silage (control) had a high pH value because of its high moisture content. Silage added with byproduct had lower acid detergent fiber (ADF) and neutral detergent fiber (NDF) contents than control silages, while its non-fiber carbohydrate (NFC), and total digestible nutrients (TDN) and lactic acid contents showed the opposite results. Silages added with crushed rice and green grain of rice were higher in lactic acid content than othor treatments as well as high DM, NFC, and TDN contents. Silage added with crushed rice and green grain of rice can be recommended as the most effective treatment for increasing forage quality and DM content of sorghum×sudangrass silage.
        53.
        2009.05 구독 인증기관·개인회원 무료
        Root knot nematode species, such as Meloidogyne hapla, M. incognita, M. arenaria and M. javanica are economically most notorious nematode pests, causing serious damage to the various crops throughout world. In this study, DNA sequence analyses of the D1-D3 expansion segments of the 28S gene in the ribosomal DNA were conducted to characterize genetic variation of the four Meloidogyne species obtained from Korea and United States. PCR-RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism), SCAR (Sequence Characterized Amplified Region) marker and RAPD (Random Amplification of Polymorphic DNA) also were used to develop the methods for exact and rapid species identification. In the sequence analysis of the D1-D3 expansion segments, only a few nucleotide sequence variation were detected among M. incognita, M. arenaria, and M. javanica, except for M. hapla. The PCR-RFLP analysis that involves amplification of the mitochondrial COII and lrRNA region yielded one distinct amplicon for M. hapla at 500 bp, enabling us to distinguish M. hapla from M. incognita, M. arenaria, M. javanica reproduced by obligate mitotic parthenogenesis. SCAR markers successfully identified the four root knot nematode species tested. We are under development of RAPD primers specific to the three root knot nematodes found in Korea.
        54.
        2009.05 구독 인증기관·개인회원 무료
        whitefly, Bemisia tabaci (Gennadius) have a wide host range including cucumber, tomato, and pepper, resulting in loss of crop yield. In this study, we tested larvicidal efficacy of several on-the-market environment–friendly agricultural materials (EFAM) to select the effective products after the target pests were stabilized in indoor rearing condition. The developmental periods of two whiteflies are as follows: in the case of T. vaporariorum, egg duration is 9.6 days, and nymph is 18.9 days, and in the case of B.tabaci, egg durationis 7.4 days, and nymph is 15.2 days under 25℃ with relative humidity (RH) of 60±5% and a photoperiod of 16L : 8D. The total period of T. vaporariorum as 5 days longer than B. tabaci. Among 22 EFAMs six products showed more than 60% of insecticide efficacy for against T. vaporariorum BTVB, BTVD, BTVG, BTVL, BTVM, and BTVS. On the other hand, seven EFAM products including showed over 60% of insecticide efficacy against B. tabaci BTVD, BTVG, BTVK, BTVL, BTVM, BTVN, and BTVU. In the case of Spodptera litura previously, xxEFAMs were tesed against 2nd instar S.litura, and EFAMs were found to have more than 90% efficacy. Test of these six EFAMs against entire larval stages were performed in this study. Although some of these products showed still more than 90% of insecticidal efficacy against up to 3rd instar larvae, the efficacy of these EFAMs sharply decreased as ages increase, result is less than 60% of efficacy of the products at most. This result indicates the difficulty to control S. litura with the on-the-market EFAMs alone under economic injury level. Collectively, it is required to find more EFAMs and find alternative method to control those insect pests tested in this study.
        55.
        2009.05 구독 인증기관·개인회원 무료
        The bumblebees, Bombus species are valuable natural resources being utilized for greenhouse pollination. Low level of genetic variation of Bombus species has been reported previously. In this study, we sequenced complete internal transcribed spacer 2 (ITS2) of the nuclear rDNA from 100 individuals of B. ardens collected from seven localities in Korean peninsula. The ITS2 sequence of B. ardens is longest, ranging in size from 1,940 bp-1,954 bp among known in insects, which ranges approximately from 241 bp-1,728 bp. The ITS2 sequences have ~51% of C+C content and contain each two 27 bp repeats, 20 bp repeats, 33 bp repeats, and 34 bp repeats at the beginning. Such repeats were not found in other insects. Uncorrected pairwise distance among 96 sequences that were obtained from 100 individuals revealed a maximum sequence divergence of 1.03%. Genetic diversity (π) of each population ranged from 0.007801 to 0.009627, and the lowest diversity was obtained from islet population of Ulleungdo, indicating possibly small, isolation of the population. Significant level of genetic distance was only found when Ulleungdo population was compared to two other mainland populations. Except for this, overall, a very high rate of per generation migration ratio (Nm=7.1-infinite) and a very low level of genetic fixation (FST=0-0.06546) were detected between pairs of localities. Analysis of hierarchical relationships among localities consistently revealed no statistically significant structure among populations. Taken these together, the B. ardens populations on the Korean peninsula are panmictic this is consistent with our understanding of the dispersal capability.
        57.
        2007.12 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to determine the effect of administration of Prostaglandin F2α (PGF2α) on semen collection training and semen characteristics in sexually inexperienced boars. Boars were moved individually to a semen collection pen and were trained to mount dummy sow. During the first and second semen collection secessions, 4 out of 17 boars and 4 out of remaining 13 boars allowed collection of semen. The 9 boars that failed semen collection from first 2 attempts received immediately 15 mg of PGF2α i.m. (intramuscular injection) upon entering the collection pen for semen collection resulted in successful semen collection from all 9 boars. Total numbers of spermatozoa were higher in PGF2α treated boars but there was no significant difference in % motility kinematics characteristics between control and PGF2α treated groups during 72 hr period. Overall, administration of PGF2α in sexually inexperienced boars increased the sex drive and facilitated the mounting activity to the dummy sow for semen collection.
        3,000원
        58.
        2007.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        본 연구는 사용 후 핵연료의 금속전환 공정에서 발생되는 폐용융염을 고형화하는 방법으로 실리카 함유 무기물을 이용하여 폐용융염을 열적, 수화학적 안정한 화합물로 전환하는 방법을 제안하였다. 실리카 함유 무기물(SAP)은 일반적인 sol-gel process로 합성되었으며, 및 로 구성된다. 제조된 SAP을 에서 폐용융염과 반응시켜 각 금속염화물에 대한 반응특성 및 열안정성을 조사하고, PCT 침출시험법을 이용하여 수화학적 안정성을 평가하였다. LiCl은 와 로, CsCl는 CS-aluminosilicate와 로, 는 로, 는 로 전환되었다. 9시간 동안 반응시킨 후, 금속염화물의 전환율은 였으며, 까지 열감량은 1wt%이하로 TGA(Thermo Gravimetric Analysis)로 확인하였다. Cs 및 Sr의 침출속도는 로 매우 높은 내침출특성을 나타내었다. 이상의 결과로부터, SAP으로 명명된 안정화제(stabilizer)는 금속염화물로 구성된 폐용융염에 대해 매우 효과적인 것으로 판단된다. SAP을 이용한 폐용융염의 고화처리방법은 후속적인 안정성의 검증과정을 통하여 폐용융염의 최종처분부피를 최소화할 수 있는 대안적인 고화방법으로 고려될 수 있을 것으로 기대 된다.
        4,000원
        59.
        2005.10 KCI 등재 구독 인증기관·개인회원 무료
        뻐ny studìes have shown the anti-proli ferative effects of irondeprivation on cancer cell s‘ but the effects 01' iron-chelators on oral cancer have not been clearly elucidated , To investigate the effects of an iron chelato r, desferrioxamine( 01"O).on the growth of ilIllTIortali zed human o1'al ke ratinocytes(IHOK), primary oraJ cancer cel ls(HN4)‘ metastatic oral cancer cell s(HN12) , and human skin keratìnocytes(HaCaT) in the MTr assay, three-dimensional(3D) raft cul tmes, Western blott ing, cell cycJ e analysis‘ nuclear staining‘ and cytochrome c expression for apoptosis s ig naling pathway were used OFO inhibited the growth of immortalized IHOK and HaCaT and mal ignant HN4 and HN12 keratinocytes in a time- and dose-dependent manner according to the MTT assay, The 3D organotypic cu l tu re also revealed that OF'O-treated cells showed less epithelial maturation, less surface keratinizati on‘ and de creased epithelia l thickness, The major mechanìsm of growth inhìbition with the micromolar 0 1"0 treatment was by the induction of apoptosis‘ which was supported by nuclear OAPI staining, ONA fragmentation analysis, and J10w cytometric analysis for sub-Gl phase ar rest and Annexin V-1"ITC stainìng, Furthermore‘ Bax expression in creased together with p53 and p21WAF1!CIPl, whìle the Bcl-2 expression decreased in the immortalized and malig nant keratinocytes treated with 01"0 , Time-dependent cytochrome c from mitochondria was observed in D1"O-treated [l-IOK and 0 1'머 cancel‘ ceJJ s, and was accompanied by the activation of caspase-3 in IHOK cells. These resu lts demonstrate that 0 1"0 has growth inhibitory effects on immortalized and malignant oral keratinocyLes Lhrough the induction of apoptosis and suggest that further evaluation of OFO as a potcntial thcrapcutic agent for human oral precancerous and cancerous lesions is warranted
        60.
        2004.12 구독 인증기관 무료, 개인회원 유료
        Human embryonic stem (ES) cells are derived from the inner cell mass of the preimplantation embryo. Human ES cells have the capacity to differentiate into various types of cells in the body. Human ES cells are indefinite source of cells for cell therapy in various degenerative disorders including neuronal disorders. Directed differentiation of human ES cells is a prerequisite for their clinical application. The objective of this study is to develop the culture condition for the derivation of neural precursor cells from human ES cells. Neural precursor cells were derived from human ES cells in a stepwise culture condition. Neural precursor cells in the form of neural rosette structures developed into neurospheres when cultured in suspension. Suspension culture of neurospheres has been maintained over 4 months. Expressions of nestin, soxl, sox2, pax3 and pax6 transcripts were upregulated during differentiation into neural precursor cells by RT-PCR analysis. In contrast, expression of oct4 was dramatically downregulated in neural precursor cells. Immunocytochemical analyses of neural precursor cells demonstrated expression of nestin and SOX1. When induced to differentiate on an adhesive substrate, neuro-spheres were able to differentiate into three lineages of neural systems, including neurons, astrocytes and oligo-dendrocytes. Transcripts of sox1 and pax6 were downregulated during differentiation of neural precursor cells into neurons. In contrast, expression of map2ab was elevated in the differentiated cells, relative to those in neural precursor cells. Neurons derived from neural precursor cells expressed NCAM, Tuj1, MAP2ab, NeuN and NF200 in immunocytochemical analyses. Presence of astrocytes was confirmed by expression of GFAP immuno-cytochemically. Oligodendrocytes were also observed by positive immuno-reactivities against oligodendrocyte marker O1. Results of this study demonstrate that a stepwise culture condition is developed for the derivation of neural precursor cells from human ES cells.
        4,000원
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