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        검색결과 74

        21.
        2010.03 구독 인증기관 무료, 개인회원 유료
        Recently, studies on natural source antioxidants have become increasingly active in various fields. Among analytical methods for assessment of antioxidant activity, the DPPH, ABTS, and TBA assays have become quite popular in natural antioxidant studies. One of the reasons is that these methods are simple to use and highly sensitive. In particular, DPPH and ABTS assays are based on the theory that a hydrogen donor is an antioxidant. The antioxidant effect can be easily evaluated by following the decrease of specific UV absorption and the results are usually expressed in terms of Trolox equivalent antioxidant capacity (TEAC). The TBA assay has been commonly used for measurement of lipid oxidation in some foods and biological systems. Because the colored complex is formed by the TBA-malonaldehyde interaction, the TBA value can be evaluated using a UV spectrophotometer or HPLC. However, the TBA-malonaldehyde complex is very unstable and often is either not detected in many oxidized lipids or is a minor product of secondary oxidation. As a result of these defects, numerous studies are ongoing.
        4,000원
        22.
        2009.12 구독 인증기관 무료, 개인회원 유료
        Pregnancy is a unique event in which a fetus develops in the uterus despite being genetically and immunologically different from the mother, and the underlying mechanisms remain poorly understood. To analyze the differential gene expression profiles in nonpregnant and 7 days post coitus (dpc) pregnant uterus of mice, we performed a global proteomic study by 2‐D gel electrophoresis (2‐DE) and MALDI‐TOF‐MS. The uterine proteins were separated using 2‐DE. Approximately 1,000 spots were detected on staining with Coomassie brilliant blue. An image analysis using Melanie III (Swiss Institute for Bioinformatics) was performed to detect variations in protein spots between pregnant and nonpregnant uterus. Twenty‐one spots were identified as differentially expressed proteins, of which 10 were up‐regulated proteins such as alpha‐fetoprotein, chloride intracellular channel 1, transgelin, heat‐shock protein beta‐1, and carbonic anhydrase II, while 11 were down‐regulated proteins such as X‐box binding protein, glutathione S‐transferase omega 1, olfactory receptor Olfr204, and metalloproteinase‐disintegrin domain containing protein TECADAM. Most of the identified proteins appeared to be related with catabolism, cell growth, metabolism, regulation, cell protection, protein repair, or protection. Our results uncovered key proteins of mouse uterus involved in pregnancy.
        4,000원
        23.
        2009.10 구독 인증기관·개인회원 무료
        Matsumuraeses phaseoli and M. falcana cannot be classified with the external morphological characters. Although differences in the morphology of male genitalia and in the mitochondrial DNA sequence of cytochrome oxidase I between the two species have been found, there is no information that the two species are biologically different species till now. We, therefore in this study, tried to cross the two species to observe postzygotic incompatibility in the next hybrid generations and to know whether the two species are 'biological species' or not. In crossing between the parents, two kinds of F1 hybrids were produced successfully. In inter- and intra-breeding between F1 hybrids, two lines crossed with females of F1 hybrid produced by females of M. phaseoli could not produce F2 adults to show inviability of larvae. The other two lines produced F2 adults successfully and the F2 adults produced F3 larvae in inbreeding. In back-crossing between parents and F1 hybrids, the two lines of 8 breeding lines, in which females of F1 hybrid were produced by females of M. phaseoli, could not produce the next generation of larvae. The other six lines produced F2 adults successfully. The results indicated that maternal factors of F1 hybrid produced by M. phaseoli females contributed to create the incompatibility between the F1 females and other lines. In conclusion, the results showed a postzygotic reproductive isolation between M. phaseoli and M. falcana in part.
        24.
        2009.06 구독 인증기관 무료, 개인회원 유료
        The Maillard Reaction Products (MRPs) such as Glucose-tyrosine (Glu-Tyr) and Xylose-arginine (Xyl-Arg) have antioxidant, antimutagenic, and antibacterial effects. However, to date, still little is known about the other biological effects of the MRPs. In this study, we investigated whether the fructose-tyrosine MRP, 2,4-bis(p-hydroxyphenyl)-2-butenal (Fru-Tyr), could modulate cell cycle progression and NF-κB activity, and thereby induce apoptotic cell death of colon cancer cells. Treatment with different concentrations (10-40 μg/ ml) of Fru-Tyr for 24 h inhibited colon cancer cell (SW620 and HCT116) growth followed by induction of G2/M phase cell cycle arrest and apoptosis in a dose-dependent manner. We also found that Fru-Tyr suppressed tumor necrosis factor-alpha (TNF-α)-induced NF-κB transcriptional activity. Moreover, Fru-Tyr induced the expression of apoptotic gene, cleaved caspse-3. These results suggest that Fru-Tyr inhibited colon cancer cell growth through induction of G2/M phase cell cycle arrest and apoptotic cell death by modulating of NF-κB.
        4,000원
        25.
        2009.05 구독 인증기관·개인회원 무료
        Apolipophorin-Ⅲ (apoLp-Ⅲ) is a hemolymph protein whose function is to facilitate lipid transport in an aqueous medium in insect. Recently, apolipophorin-Ⅲ in Galleria mellonella and Hyphantria cunea was shown to play an unexpected role in insect immune activation. We show here a novel possible function/role of apoLp-Ⅲ in insects. To investigate the genes which have a relationship with apoLp-Ⅲ in fall webworm larvae, we reduction of endogenous Hc apoLp-Ⅲ mRNA levels in larvae via RNA interference (RNAi). The RNAi-mediated Hc apoLp-Ⅲ reduction resulted in the reduction of antioxidants, like MnSOD, catalase, and glutathione S transferase as well as immune proteins. In particular, expression of MnSOD commonly decreased in fat body, midgut, and hemocytes following the knockdown of Hc apoLp-Ⅲ, which induced an elevated level of superoxide anion in H. cunea larvae. The observed effect of Hc apoLp-Ⅲ RNAi suggests that Hc apoLp-Ⅲ is related to the action/expression of antioxidants.
        26.
        2009.05 구독 인증기관·개인회원 무료
        Innate immunity responses are triggered by the immune challenge and therefore involve signaling processes. The cellular response is initiated by hemocytes and mainly involves phagocytosis and encapsulation of intruders by these cells. To address whether Hc-STAT is activated upon bacterial challenge, we examined the subcellular location of STAT protein in hemocyte by immunostaining. A new insect member of the STAT family of transcription factors (Hc-STAT) has been cloned from the lepidopteran, Hyphantria cunea. The domain involved in DNA interaction and the SH2 domain are well conserved. The gene is transcribed at a low level during all stages of development, and the protein is present in hemocytes, fat body, midgut, epidermis, and Malphigian tuble (Mt). Especially, hemocytes and Mt showed transcriptional activation of Hc-STAT upon Gram (-) bacteria and fungal challenge. Gram (-) bacteria and fungal challenge specifically results in nuclear translocation of Hc-STAT protein and induction of DNA-binding activity that recognizes a STAT target site in H. cunea hemocyte. In vitro treatment with pervanadate translocates Hc-STAT to the nucleus in hemocyte cells. Here we report the first evidence for the involvement hemocyte JAK/STAT pathway upon microbial infection in lepidopteran insect.
        28.
        2008.10 구독 인증기관·개인회원 무료
        As indigenous aphid parasitoid, Aphelinus varipes kill aphids for feeding in addition to parasitization. Because of this characteristic of A. varipes, this parasitoid may have the possibility of biological control agent against aphids. So we have evaluated traits such as daily paratization, total parasization, number of aphids killed by host feeding, sex ratio, development time, pupal mortality of A. varipes parasitizing green peach aphid, Myzus persicae. At 25°C and 16L:8D, longevity, total paratization and host feeding of A. varipes female was 11.0, 25.3, and 63.3 days, respectively. And development time of male and female, sex ratio (M:F), pupa mortality of offspring of A. varipes were 12.0 days, 12.5 days, 0.88, and 11.6%, respectively. However, because these results are not enough to estimate potential of A. varipes as biological control agents/factors, other factors such as host suitability (Macrosiphum euphorbiae, Aulacorthum solani), effect of temperature, and host seeking behavior of A. varipes continually will be investigated.
        29.
        2008.10 구독 인증기관·개인회원 무료
        Bt crystal proteins, encoded by cry genes, are a group of insecticidal proteins unique in the Gram-positive and spore-forming bacterium, Bacillus thuringiensis. These cry genes are widely applied as one of the most successful candidates for constructing transgenic crops resistant to pest insects. In our previous report, we found Cry1-5 had high insecticidal activity against Spodoptera larvae although its amino acid sequences showed high similarity (95.6%) to those of Cry1Ac which had low activity. In comparison with Cry1Ac, Cry1-5 had 12 different residues on domain I and II. In order to convert these residues to Cry1-5 randomly, 10 mutagenic primers were designed. Through multi site-directed mutagenesis, we mutated the modified cry1Ac gene by plant codon usage in pOBI-Modcry1Ac based on cry1-5 and constructed 63 mutant cry genes. Among them, 10 mutant cry genes on domain II were selected and their recombinant proteins were expressed by baculovirus expression system. From bioassay results to P. xylostella and S. exigua, we found some mutants have high insecticidal activities to be applicable to transgenic crops.
        30.
        2008.10 구독 인증기관·개인회원 무료
        Innate immunity responses are triggered by the immune challenge and therefore involve signaling processes. The cellular response is initiated by hemocytes and mainly involves phagocytosis and encapsulation of intruders by these cells. To address whether Hc-STAT is activated upon bacterial challenge, we examined the subcellular location of STAT protein in hemocyte by immunostaining. A new insect member of the STAT family of transcription factors (Hc-STAT) has been cloned from the lepidopteran, Hyphantria cunea. The domain involved in DNA interaction and the SH2 domain are well conserved. The gene is transcribed at a low level during all stages of development, and the protein is present in hemocytes, fat body, midgut, epidermis, and Malphigian tuble (Mt). Especially, hemocytes and Mt showed transcriptional activation of Hc-STAT upon Gram (-) bacteria and fungal challenge. Gram (-) bacteria and fungal challenge specifically results in nuclear translocation of Hc-STAT protein and induction of DNA-binding activity that recognizes a STAT target site in H. cunea hemocyte. In vitro treatment with pervanadate translocates Hc-STAT to the nucleus in hemocyte cells. Here we report the first evidence for the involvement hemocyte JAK/STAT pathway upon microbial infection in lepidopteran insect.
        31.
        2008.10 구독 인증기관·개인회원 무료
        As an effective generalist predator of aphids and other hemipteran pests, Harmonia axyridis has been a successful biological control agent. Interestingly, it was known that there were varied in color patterns on H. axyridis elytra. In fact, Seo & Youn (2007) reported that H. axyridis had five color patterns, for example, succinea 1, 2, conspicua, spectabilis, and axyridis. But there are uncertain that H. axyridis elytra colour patterns are regulated by genetic polymorphism. So we tried to what is the reason that color patterns are greatly variable. To identify DNA markers linked to a elytra polymorphism, amplified fragment length polymorphism (AFLP) analysis was performed on DNA samples from four female succinea, conspicua, spectabilis and Coccinella septempunctata which is another species in Coccinellidae. AFLP analysis with the restriction endonuclease combination EcoRⅠ and MseⅠwas performed. Using 12 AFLP primer pairs, nine AFLP fragments which is specific between succinea, conspicua, spectabilis was identified. These nine AFLP fragments were isolated, cloned and sequenced. Subsequent UPGMA cluster analysis revealed three major group of H. axyridis populations. These genetic tree showed that H. axyridis elytra colour diversity was affected by genetic polymorphism. For more genetically understanding elytra colour genes, different primer combinations may be need to be generate enough polymorphic markers. These genetic analyses may be facilitate the understanding of molecular mechanism behind wing colour pattern formation.
        32.
        2008.06 구독 인증기관 무료, 개인회원 유료
        Oral spirochetes are anaerobes known as one of causative agents for periodontal diseases. In this study, we investigated the possibility of utilizing fluorescent fatty acids for labeling oral spirochetes. Bacterial labeling was standardized with three different lengths of fluorescent fatty acids: 5-octadecanoylaminfluorescein (OAF), 5-dodecanoylamin-fluorescein (DAF), and 5-hexadecanoylaminfluorescein (HAF). Among these fatty acids, OAF showed the best labeling activity. Treponema denticola ATCC 35405 was totally saturated to the maximum when incubated with OAF 1μM/mℓ for 1 hour. Treponema vincentii LA-1 also increased in fluorescence in proportion to incubation time length and the concentration. In conclusion, these findings showed the possibility that the fluorescent fatty acid can be used for labeling oral spirochetes.
        4,000원
        33.
        2008.05 구독 인증기관·개인회원 무료
        Bt crystal proteins, encoded by cry genes, are a group of insecticidal proteins unique in the Gram-positive and spore-forming bacterium, Bacillus thuringiensis. These cry genes are widely applied as one of the most successful candidates for constructing transgenic plants resistant to pest insects. In our previous report, we found Cry1-5 had high insecticidal activity against Spodoptera larvae although its amino acid sequences showed high similarity (97.9%) to those of Cry1Ab which had low activity. In comparison with Cry1Ac, Cry1-5 had 12 different residues in domain Ⅰ and domain Ⅱ, and we focused on domain Ⅰand domain Ⅱ regions and designed 10 mutagenic primers to change 12 residues. Through multi site-directed mutagenesis, we mutated the modified cry1Ac gene by plant codon usage in pOBⅠ-Mod-cry1Ac based on cry1-5 and constructed 63 various mutant cry genes. In the further study, we will express those mutant proteins as a fusion form with polyhedrin using baculovirus expression system and subsequently do bioassay to Spodoptera larvae.
        34.
        2008.05 구독 인증기관·개인회원 무료
        The surface of most coccinellids (particularly the elytra) has characteristic colour patterns, which show great variability within many species. Individuals of a species of ladybird often differ from one another in colour and pattern. In case of Harmonia axyridis, environmental factors, such as temperature or food, can probably influence colour and pattern. However, virtually no work has been carried out in the influence of such factor. Therefore, in this study, according to rearing temperature, photoperiod and diet, variation of elytra color patterns were investigated. First instar larva on each color pattern were reared in an incubator at one of two temperatures; 25 and 30℃, under the following photoperiod; L16: D8, L12: D12 and L8: D16 and were provided three species of aphids. And their color pattern of adults were estimated.
        35.
        2008.05 구독 인증기관·개인회원 무료
        The multicolored Asian ladybird beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), is common to a wide range of natural and agricultural habitats. Applications of gamma irradiation minimized the losses of stored food and the death or failure of emergence in larval and pupal stages. On the other hand, degrade toxin waste as one of alternative to chemical pesticide for both quarantine and sprout control purposes of storage crop pest. So, we have investigated whether gamma irradiation exposed to eggs, lava, pupa and adults of H. axyridis. It may be affected the emergence, fertility, fecundity, development period and sex ratio of H. axyridis. Some changes of physiological characteristics may be applied to more efficient agents as biological control of several aphids. Insects were exposed to gamma irradiation from 0 to 500 Gy of 60Co depended on their developmental stages. The results showed that the first instar, eggs, third instar, pupae, and adults were more sensitive in order of irradiation dose. And fecundity and fertility of female adults were significantly decreased with increasing gamma irradiation dose at all tested individuals.
        36.
        2005.06 구독 인증기관 무료, 개인회원 유료
        Cloned calves derived from somatic cell nuclear transfer (SCNT) have been frequently lost by sudden death at 1 to 3 month following healthy birth. To address whether placental anomalies are responsible for the sudden death of cloned calves, we compared protein patterns of 2 placentae derived from SCNT of Korean Native calves died suddenly at two months after birth and those of 2 normal placentae obtained from AI fetuses. Placental proteins were separated using 2-Dimensional gel electrophoresis. Approximately 800 spots were detected in placental 2-D gel stained with coomassie-blue. Then, image analysis of Malanie III (Swiss Institute for Bioinformatics) was performed to detect variations in protein spots between normal and SCNT placentae. In the comparison of normal and SCNT samples, 8 spots were identified to be up-regulated proteins and 24 spots to be down-regulated proteins in SCNT placentae, among which proteins were high mobility group protein HMG1, apolipoprotein A-1 precursor, bactenecin 1, tropomyosin beta chain, H+-transporting ATPase, carbonic anhydrase II, peroxiredoxin 2, tyrosine-rich acidic matrix protein, serum albumin precursor and cathepsin D. These results suggested that the sudden death of cloned calves might be related to abnormal protein expression in placenta.
        4,000원
        37.
        2005.06 구독 인증기관 무료, 개인회원 유료
        Postantibiotic effects (PAE) refer to suppression of the bacterial growth following limited periods of exposure to an antibiotic and subsequent to the removal of the antibiotic agent. Fusobacterium nucleatum and Porphyromonas gingivalis are Gram-negative anaerobic bacteria associated with several periodontal diseases. In this study, postantibiotic effects (PAE), postantibiotic sub-MIC effect (PA SME) and sub-MIC effect (SME) of antibiotics on F. nucleatum ATCC 25586 and P. gingivalis W50 were investigated. The PAE was induced by 10X the MIC of antibiotic and antibiotic was eliminated by washing. The PA SMEs were studied by addition of 0.1, 0.2 and 0.3X MICs during the postantibiotic phase of the bacteria, and the SMEs were studied by exposition of the bacteria to antibiotic at the sub-MICs only. Amoxicillin, doxycycline and tetracycline induced PAE for F. nucleatum ATCC 25586 and P. gingivalis W50. But metronidazole and penicillin induced PAE for only F. nucleatum ATCC 25586. Metronidazole and doxycycline induced PA SME and SME for both species of anaerobic bacteria used in this study. The PA SME values for both strains were substantially longer than the SME values. The present study showed the existence of PAE, PA SME and SME for various antibiotics against F. nucleatum ATCC 25586 and P. gingivalis W50.
        4,000원
        39.
        2002.10 구독 인증기관 무료, 개인회원 유료
        The main objective of this paper to purpose a evaluating methods of process capability measures for exponential distributed quality characteristics. For correctly evaluating process capability , the first thing , exponential data is applied the Lilliefors test statistic to the null hypothesis of nornality. The next , exponential parameters is estimated in terms of MLE , ME , MME and then evaluated , respectively , process capability index based on exponential curved (Cpe). We consider simultaneously process capability messures based on Pearson system, Johnson system and Burr system.
        4,000원
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