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        검색결과 252

        122.
        2012.10 구독 인증기관·개인회원 무료
        We investigated the molecular and kinetic properties of two acetylcholinesterases (AmAChE1 and AmAChE2) from the Western honey bee, Apis mellifera. Western blot analysis revealed that AmAChE2 has most of catalytic activity rather than AmAChE1, further suggesting that AmAChE2 is responsible for synaptic transmission in A. mellifera, in contrast to most other insects. AmAChE2 was predominately expressed in the ganglia and head containing the central nervous system (CNS), while AmAChE1 was abundantly observed not only in the CNS but also in the peripheral nervous system/non-neuronal tissues. Both AmAChEs exist as homodimers; the monomers are covalently connected via a disulfide bond under native conditions. However, AmAChE2 was associated with the cell membrane via the glycophosphatidylinositol anchor, while AmAChE1 was present as a soluble form. The two AmAChEs were functionally expressed with a baculovirus system. Kinetic analysis revealed that AmAChE2 has approximately 2,500-fold greater catalytic efficiency toward acetylthiocholine and butyrylthiocholine than AmAChE1, supporting the synaptic function of AmAChE2. In addition, AmAChE2 likely serves as the main target of the organophosphate (OP) and carbamate (CB) insecticides as judged by the lower IC50 values against AmAChE2 than against AmAChE1. When OP and CB insecticides were pre-incubated with a mixture of AmAChE1 and AmAChE2, asignificant reduction in the inhibition of AmAChE2 was observed, suggesting a protective role of AmAChE1 against xenobiotics. Taken together, based on their tissue distribution pattern, molecular and kinetic properties, AmAChE2 plays a major role in synaptic transmission, while AmAChE1 has non-neuronal functions, including chemical defense.
        124.
        2012.05 구독 인증기관·개인회원 무료
        The cotton aphid, Aphis gossypii (Glover), is one of the most serious pest in seed potato and various vegetable cultivation. The imidacloprid-resistant strain (IR) was over 300-fold more resistant to imidacloprid compared to a susceptible strain (S) as judged by LC50 values. A highly imidacloprid-resistant local field population (L) was collected from cucumber at Gangwha island in 4th August 2011. Even though neonicotinoid insecticides especially imidacloprid were sprayed six times during June and July, aphid density was too high to be counted. To identify differentially expressed genes in IR or L, comparative transcriptome analyses based on GS-FLX were conducted using total RNAs extracted from IR, L and S strains. Futhermore, to search the resistance associated proteins in IR or L, comparative proteome analyses based on 2DE were conducted using total proteins extracted from IR, L and S strains. Few common candidate genes detected among IR and L such as ABC genes. Comparison of the nucleotide sequence of six nicotinic acetylcholine receptor (nAChR) subunit (alpha 1-5, beta 1) genes from IR, L and S strain revealed a point mutation in the loop D region of the nAChR beta 1 subunit of the IR, causing an arginine to threonine substitution (R81T). These mechanisms also reported in Myzus persicae and this amino acid change confers a vertebrate-like character to the insect nAChR and results in reduced sensitivity to neonicotinoids.
        125.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study effectiveness of core strengthening exercise programs on symmetric double limb support and balance ability for elderly. The subjects that 30 persons between the ages of 65~80 elderly participated were divided into two groups randomly for 8 weeks. Tetrax interactive balance system and Berg's balance scale were used to assess support and stability. Paired t-tests were used to evaluate the changes before and after intervention. The difference between the groups was compared using an independent t-test. The experimental group showed significantly increase weight support, stability, balance(p<.05). However, the control group not showed significantly increase weight support, stability, balance(p>.05). In a variation, experimental and control groups showed significantly increased rate of weight support, stability, balance(p<.05). Consequently, core strengthening exercise program should be considered as a therapeutic method for the elderly to improve the balance ability and effectiveness on falls.
        4,000원
        126.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Hemorrhagic Escherichia coli (E. coli) is one of the most important agent of diarrhea in piglet. The aim of this study was to investigate the characteristics of virulence genes and genetic diversity in hemorrhagic E. coli isolated from piglets with diarrhea. Among 122 hemorrhagic E. coli, 62 isolates carried single toxin gene like heat-stable toxin (ST), heatlabile toxin (LT), verotoxin 1 (VT1), verotoxin 2 (VT2), spa and eae. The most prevalent toxin gene carried by isolates was ST gene (23 isolates), while the most common association was ST/LT (14 isolates) and ST/LT/VT2 (13 isolates). In pulsed field gel electrophoresis, isolates were not classified as one cluster by epidemiological information including isolated area, isolated year and possessed toxins.
        3,000원
        127.
        2011.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to examine the effects of gait training using functional electrical stimulation on the improvement of hemiplegic patients' functions for balance and gait velocity. The subjects of the experiment were determined to be 10 each hemiplegic patients who had been diagnosed with stroke or brain damage six months or longer earlier assigned to an experimental group and a control group respectively. The subjects were evaluated before the experiment using Tetrax and 10M gait tests, received gait training five times a week for four weeks using functional electrical stimulation and were evaluated after the experiment in the same method as used in the evaluation before the experiment. In order to examine differences between the experimental group that received gait training using functional electrical stimulation and the control group that was treated by functional electrical stimulation and received gait training thereafter, differences between before and after the experiment were analyzed using paired sample t-tests and differences in changes after the experiment between the experimental group and the control group were analyzed using independent sample t-tests in order to compare the two groups with each other. Experimental results showed significant differences in weight bearing, balance and gait velocity between before and after the experiment in the experimental group(p<.05). In the control group, whereas weight bearing and gait velocity did not show any significant difference between before and after the experiment(p>.05), balance showed significant differences(p<.05). Weight bearing, balance and gait velocity change rates showed significant differences between the experimental group and the control group(p<.05). In conclusion, it was indicated that gait training using functional electrical stimulation is effective for enhancing stroke patients' weight bearing rates, balance abilities and gait velocity.
        4,000원
        128.
        2011.10 구독 인증기관·개인회원 무료
        Testes‐derived unipotent male germ‐line stem (GS) cells can acquire multipotency under appropriate culture conditions to become mGS cells which can contribute to all three germ‐layers. This study was designed to investigate the epigenetic characteristics of mGS cells derived from adult mouse testes (maGS cells). The GS cells were isolated from 4 6 week DBA mouse and were cultured in Dulbecco’s modified Eagle Medium supplemented with 15% (v/v) fetal bovine serum, 1,000 U/ml LIF, 4 ng/ml GDNF at 37℃ in an humidified atmosphere of 5% CO2 in air to derive the maGS cells. The multipotency of maGS cells were verified by morphological and gene expression analyses, teratoma formation upon transplantation into nude mouse and in vitro differentiation ability. Bisulfite genomic sequencing revealed that GS cells had androgenetic DNA methylation pattern at the Igf2‐H19, Gnas‐Nespas , and Dlk1‐Dio3 imprinted gene clusters which changed to hemi‐zygotic embryonic stem (ES)‐cell like pattern in the maGS cells. Western blot analysis, using modification‐ and residue‐specific antibodies, revealed that both maGS and ES cells had similar level of histone di‐methylation at 4th and 27th lysine residue of histone 3 (H3K4me2 and H3K27me2) which represent “bivalent domain” for regulating self‐renewal and differentiation of mouse ES cells. Both maGS and ES cells also shared similar hisone modification for H3K9me2, H3K79me2, H3K9ac and H3K18ac. However, maGS cells had higher level of H3K- 36me2 and H3S10p. These data suggest that maGS and ES cells share several epigenetic characteristics but they also have their own unique epigenetic marks that may be useful as a molecular marker for their identification.
        129.
        2011.10 구독 인증기관·개인회원 무료
        The cotton aphid, Aphis gossypii (Glover), is one of the most serious pest in the cultivation of various vegetables. A highly imidacloprid-resistant field population (CA-L) was collected from cucumber at Gangwha island in 4th August 2011. Even though neonicotinoid insecticides especially imidacloprid were sprayed six times during June and July, aphid density was too high to be counted. IEF and 2DE analyses revealed that general esterase isozyme (pI. 5) in CA-L were dramatically overexpressed and more isozyme spots identified in CA-L compared to susceptible (CA-S) strain. To identify differentially expressed genes in CA-L, comparative transcriptome analyses based on GS-FLX were conducted with total RNA extracted from CA-L, which generated ca. 143 Mb reads. Previously reported, comparative transcriptome analyses performed in imidacloprid resistant (CA-IR) and CA-S. The comparative transcriptome analyses re-investigated after all data sets were combined together. As previously reported, seven ATP-binding cassette (ABC) transporter genes were newly identified in A. gossypii, among which only ABCC9 gene was highly expressed in CA-IR and L. These results suggested that ABCC subfamily associated with imidacloprid resistance in A. gossypii.
        130.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to investigate the antimicrobial resistance pattern and distribution of resistance gene determinants in fecal E. coli from chicken. Antimicrobial susceptibility test was performed on a total of 109 fecal E. coli isolates from chicken, collected in Gyeonggi, Chungbuk, Jeonnam and Jeonbuk province from March to November 2003, by the disk agar diffusion method. Eighteen commonly used antimicrobial agents approved in Korea as veterinary medicine were tested: ampicillin (AM), amoxicillin/clavulanic acid (AMC), cephalothin (CF), cefozolin (CZ), cefoxitin (FOX), cefotaxime (CTX), cefepime (FEP), imipenem (IPM), streptomycin (S), gentamicin (GM), amikacin (AN), ciprofloxacin (CIP), enrofloxacin (ENO), norfloxacin (NOR), trimethoprim/sulfamethoxazole (SXT), erythromycin (E), chloramphenicol (C) and tetracycline (TE). Higher resistance rates (≥50%) were observed against 9 antimicrobial agents including AM, CF, S, CIP, ENO, NOR, SXT, E and TE. Resistance was most frequent for TE in 105 E. coli isolates (96.3%). Twenty-two isolates (20.2%) of the isolates showed multiple antimicrobial resistance to 8, and 19 isolates (17.4%) showed to 7 antimicrobial agents. The distribution of the resistance gene determinants for S and TE was assessed by PCR in resistant isolates. Thirty isolates possessed the strA, strB, and aadA gene, 25 isolates possessed the strA and strB gene among the 66 streptomycin-resistant isolates. Fifty one isolates possessed only the tetA gene, 22 isolates possessed the tetA and tetB gene, 11 isolates possessed only the tetB gene among the tetracycline-resistant isolates.
        4,000원
        131.
        2010.12 KCI 등재 구독 인증기관·개인회원 무료
        World wide mushroom productions have been increased to 10-20% and more various mushrooms have been attempted to cultivate. Similar trends were also observed in Korea. More diverse mushroom varieties such as Pleurotus eryngii, Hericium erinaceus and Agrocybe aegerita have been attempted to cultivate in larger areas. In these days, 235 varieties of 33 different mushroom species have been cultivated. However only 50 varieties were protected by the law. Since 1960s, mushroom industry had been considered as one of the major export industries in Korea and mushroom production has been rapidly increased. In 2008, total mushroom production was about 198,209 ton, which were about 800 billion won (one trillion won if include mushroom factory products). Major cultivated species are Pleurotus ostreatus, P. eryngii, Flammulina velutipes, Lentinula edodes and Agaricus bisporus, which cover 90% of total production. We believed that the protection of mushroom vavarieties by the law is one of the main problems to be solved. Also, more studies to develop better mushroom production methods with low cost and improve the distribution structures are certainly required. In these days, the export of mushroom has been increased in Korea. We imported more mushrooms than exported for last 4 years, however, it has been changed that export is getting bigger in these days. Because we developed the liquid spawning and automatic cultivation systems, which lead the reduction of mushroom production cost and resulted in the increasement of export. If we develop better post-harvest system, it is certain that the mushroom export should be more important in the future. As an alternative way, some Korean companies are planning to build the plants in main export countries. Mushroom industry has promising future because mushroom is good for your health.
        135.
        2010.06 구독 인증기관 무료, 개인회원 유료
        Selenoprotein S (SelS) is widely expressed in diverse tissues where it localizes in the plasma membrane and endoplasmic reticulum. We studied the potential function of SelS in erythrocyte differentiation using K562 cells stably over-expressing SelS wild-type (WT) or one of two SelS point mutants, U188S or U188C. We found that in the K562 cells treated with 1μM Ara-C, SelS gradually declined over five days of treatment. On day 4, intracellular ROS levels were higher in cells expressing SelS-WT than in those expressing a SelS mutant. Moreover, the cell cycle patterns in cells expressing SelS-WT or U188C were similar to the controls. The expression and activation of SIRT1 were also reduced during K562 differentiation. Cells expressing SelS-WT showed elevated SIRT1 expression and activation (phosphorylation), as well as higher levels of FoxO3a expression. SIRT1 activation was diminished slightly in cells expressing SelS-WT after treatment with the ROS scavenger NAC (12 mM), but not in those expressing a SelS mutant. After four days of Ara-C treatment, SelS-WT-expressing cells showed elevated transcription of β-globin, y-globin, ε-globin, GATA-1 and zfpm-1, whereas cells expressing a SelS mutant did not. These results suggest that the suppression of SelS acts as a trigger for proerythrocyte differentiation via the ROS-mediated downregulation of SIRT1.
        4,000원
        137.
        2009.06 구독 인증기관 무료, 개인회원 유료
        Periodontal ligament (PDL) tissue is a connective tissue that is interposed between the roots of the teeth and the inner wall of the alveolar bone socket. PDL is always exposed to physiologic mechanical force such as masticatory force and PDL cells play important roles during orthodontic tooth movement by synthesizing and secreting different mediators involved in bone remodeling. The Wnt/β-catenin signaling pathway was recently shown to play a significant role in the control of bone formation. In the present study, we applied cyclic tensile stress of 20% elongation to cultured human PDL cells and assessed its impact after six days upon components of the Wnt/β-catenin signaling pathway. RTPCR analysis showed that Wnt1a, Wnt3a, Wnt10b and the Wnt receptor LRP5 were down-regulated, whereas the Wnt inhibitor DKK1 was up-regulated in response to these stress conditions. In contrast, little change was detected in the mRNA expression of Wnt5a, Wnt7b, Fz1, and LRP6. By western blotting we found decreased expression of the β-catenin and p-GSK-3β proteins. Our results thus show that mechanical stress suppresses the canonical Wnt/β-catenin signaling pathway in PDL cells.
        4,000원