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        검색결과 393

        141.
        2013.05 구독 인증기관·개인회원 무료
        The Hypsizigus marmoreus has been used as medicinal and food source in worldwide. Viridans Streptococci, which include Streptococcus sanguinis and Streptococcus gordonii, are pioneer oral bacteria that initiate dental plaque formation. This study was to investigate the antimicrobial activity of Hypsizigus marmoreus Extracts. Antimicrobial activity of extracts were tested against pathogenic bacteria (Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus sanguinis and Streptococcus gordonii) by paper disc methods. The Hypsizigus marmoreus Extracts were extracted with 80% methanol. The 80% methanol extracts of Hypsizigus marmoreus Extracts showed antimicrobial activity against S. sanguinis and S. gordonii. The 80% methanol extract of Hypsizigus marmoreus Extracts were fractioned by hexane, chloroform, ethylacetate and buthanol. The ethylacetate fraction of Hypsizigus marmoreus Extracts showed strong antimicrobial activity against S. sanguinis and S. gordonii with minimum inhibitory concentration (MIC) range of 0.8-1 mg/ml. Especially, the 80% methanol extract and ethylacetate fraction of Hypsizigus marmoreus Extracts were inhibited the biofilm formation of S. sanguinis and S. gordonii at a concentration of 1.0 mg/ml. These results suggest that Hypsizigus marmoreus extracts can be developed as a potent antimicrobial agent.
        142.
        2013.04 구독 인증기관·개인회원 무료
        Worldwide studies on Apis cerana variation for biogeography and genetic diversity depended largely on a 86~93 bp-long mitochondrial non-coding region (internal spacer region) located between tRNALeu and COII (named as NC2), possibly due to higher variability among available markers. In order to incorporate the A. cerana occurring in South Korea into world extensive data, we also sequenced the NC2 from 118 A. cerana samples collected over nine Korean localities and 66 A. cerana samples over seven Asian localities, such as China, Vietnam, and Thailand. These data were combined with preexisting world data to scrutinize genetic relationships of A. cerana in South Korea to outside distributional range. Sequencing of 184 samples provided a total of ten haplotypes: five from Korea, six from China, one from Vietnam, and two from Thailand. Among them eight were new, whereas two were previously reported ones. Phylogenetic analysis of A. cerana NC2 haplotypes so far found including ours has confirmed the presence of four major groups of A. cerana (Asian mainland group, Sundaland group, Palawan group, and Luzon-Mindahnao group) and all haplotypes found in this study also were included in the Asian mainland group. In order to find further variable regions that can be used as sequence-based marker several mitochondrial non-coding regions and nuclear intron regions are in the middle of testing.
        144.
        2012.12 구독 인증기관 무료, 개인회원 유료
        Although bombesin (BN) regulates colonic motility, the associated mechanism of action remains unclear. The objective of this study was to investigate the effect of BN on colonic motility using isolated rat colon. An isolated rat colon was perfused with Krebs solution via the superior mesenteric artery. Intraluminal pressure was measured via microtip catheter pressure transducers at both proximal and distal portions of the isolated colon. After a control period, BN was administered intraarterially in concentrations of 13, 26, 130, and 260 pM. After pretreatment with hexamethonium (10-3 M), atropine (10-5 M), or tetrodotoxin (10-6 M), BN was administered at a concentration of 260 pM (proximal colon) or 130 pM (distal colon); intraluminal pressure was then monitored. Changes in motility were expressed as the percentage change of motility index (MI) over the basal period. As a result, BN increased colonic motility and a dose-dependent increase in proximal colonic motility was observed. The stimulant effect of BN was almost completely abolished by atropine and tetrodotoxin at both the proximal and distal colon. However, BN was not inhibited by hexamethonium at both the proximal and distal colon. Therefore, the stimulant action of BN may be mediated by local cholinergic muscarinic receptors.
        4,000원
        145.
        2012.12 구독 인증기관 무료, 개인회원 유료
        Vital pulpotomy is a very useful method for disarming of canine tooth, tooth fracture, periodontitis, and malocclusion in veterinary dentistry. Calcium hydroxide is the material commonly used as a liner during vital pulpotomy. This creates a mineralized barrier by stimulating osteoblastic hard tissue repair, arrests the inflammatory response, and soothes dentin. However, the powder or mix type calcium hydroxide materials have many disadvantages due to complicated procedures for use and are hard to handle when vital pulpotomy is followed under general anesthesia in animals. This study was conducted in order to compare the effect of mix and premixed paste type calcium hydroxide as a liner in vital pulpotomy. Six beagle dogs underwent hemisection on the mesial root of the mandibular first molar and vital pulpotomy on the distal root of the first molar. On the distal root of the left and right mandibular first molar, mix type (DYCAL®, Dentsply, USA) and premixed paste type calcium hydroxide (VITAPEX®, Morita, Japan) were used as liners, respectively. Radiological evaluation was performed at immediate, 4, 12, and 20 weeks after vital pulpotomy. According to the results, all teeth had well-formed dentinal bridges, and there were no periradicular lucency, lamina dura loss, or anomalies of the pulp cavity. According to these results, on vital pulpotomy in animals, premixed paste type calcium hydroxide was easy to handle and decreased the anesthesia period due to a more convenient application procedure. A further study of many clinical cases is needed for evaluation of side effects and other problems.
        4,000원
        146.
        2012.11 구독 인증기관·개인회원 무료
        The mushrooms have been used as traditional medicines and food resources in many countries. The objective of this study was to determine antioxidant compounds and to evoluate tyrosinase inhibitory activity of extracts from Hypsizigus marmoreus. The pileus and stipe of Hypsizigus marmoreus were extracted with methanol and water, separately. The methanol extract of Hypsizigus marmoreus were fractioned by hexane, chloroform, ethylacetate and buthanol. The concentrations of total polyphenolics and flavonoids in methanol extracts were investigated by colorimetric methods. The concentrations of total polyphenolics and flavonoids in methanol extract of the pileus was higher than methanol extract of the stipe. The DPPH redical scavenging activity of the pileus extract was also higher than stipe extract in methanol extract. The IC50 of DPPH redical scavenging activity of the pileus and stipe in methanol extract were 18 mg/ml and 1 10 mg/ml, respectively. The IC50 of tyrosinase inhibitory activity of the pileus and stipe in methanol extract were 500 mg/ml and 1,000 mg/ml in methanol extract. These results suggest that Hypsizigus marmoreus can be potentially used as a source of natural antioxidant agent in the cosmetic industry as well as the food, pharmaceutical and medicinal industry.
        147.
        2012.09 구독 인증기관 무료, 개인회원 유료
        Probiotics, enzymes, organic acids, oligosaccharides, antioxidants, and other functional materials are actively being explored as alternatives to antibiotics. Probiotics include live beneficial microorganisms that colonize the intestinal tract and competitively inhibit attachment and growth of harmful microbes. Probiotics also increase feed efficiency by assisting in nutrient absorption and digestion. The current study was conducted in order to evaluate the effect of a new probiotic, CS-A, as a dietary supplement of a fermented product on growth performance, feed intake, and feed conversion efficiency in broiler chickens, and to evaluate its value as an alternative for antibiotics used as a feed additive. Antibacterial and anti-inflammatory effects of CS-A were investigated in vitro and the in vivo effects of a constant concentration of supplemented CS-A on growth rate and feed efficiency were evaluated. In addition, the safety of CS-A was assessed by examination of common symptoms and mortality. Determination of minimal inhibitory concentration revealed an excellent antibacterial effect of CS-A. Cytotoxicity was low and anti-inflammatory effects were achieved at the effective concentration of CS-A. Supplementation with 0.1% CS-A resulted in a feed efficiency score of 1.84 in broilers, compared to 2.00 in the control group. There were no adverse clinical findings, necropsy findings, hematology, and altered serum biochemistry parameters, and no mortality. Thus, it is concluded that CS-A is safe and effective as a feed additive.
        4,000원
        148.
        2012.06 구독 인증기관·개인회원 무료
        Pluripotent stem cells can be derived from both pre- and post-implantation embryos. Embryonic stem cells (ES cells), derived from inner cell mass (ICM) of blastocyst are naïve pluripotent and epiblast stem cells (EpiSCs) derived from post-implantation epiblast are primed pluripotent. The phenotypes and gene expression patterns of the two pluripotent stem cells are different each other and EpiSCs thought to be in a more advanced pluripotent (primed pluripotent state) than mouse ES cells (naïve pluripotent state). Therefore, we questioned whether EpiSCs are less potential to be differentiated into specialized cell types in vitro. EpiSCs were isolated from 5.5~6.5 day post coitum mouse embryos of the post-implantation epiblast. The EpiSCs could differentiate into all tree germ layers in vivo, and expressed pluripotency markers (Oct4, Nanog). Interestingly, EpiSCs also were able to efficiently differentiate into neural stem cells (NSCs). The NSCs differentiated from EpiSCs (EpiSC-NSCs) expressed NSC markers (Nestin, Sox2, and Musasi), self-renewed over passage 20, and could differentiate into two neural subtypes, neurons, astrocytes and oligodendrocytes. Next, we compared global gene expression patterns of EpiSC-NSCs with that of NSCs differentiated from ES cells and brain tissue. Gene expression pattern of brain tissue derived NSCs were closer to ES cell-derived NSCs than EpiSC-NSCs, indicating that the pluripotent stem cell-derived somatic cells could have different characteristics depending on the origin of pluripotent stem cell types. * This work was supported by the Next Generation Bio-Green 21 Program funded by the Rural Development Administration (Grant PJ 008009).
        149.
        2012.06 구독 인증기관·개인회원 무료
        Neural stem cells (NSCs) are self-renewing tripotent cell populations and have capacity of neuronal (neurons) and glial (astrocytes and oligodendrocytes) differentiation. Many researchers have reported that NSCs have therapeutic effects in neurological disease by transplantation. However, it is not easy to obtain NSCs in vitro. Recently, Yamanaka and colleagues showed that somatic cells could be reprogrammed into pluripotent state by enforcing reprogramming factors. Induced pluripotent stem (iPS) cells undergo unlimited self-renewal and have differentiation potential into various types of cells like embryonic stem cells. Direct differentiation into a specialized cell types from iPS cells hold considerable promise for regenerative medicine as well as basic research. Here, we induced differentiation of iPS cells into NSCs in vitro and in vivo, which were compared with embryonic stem (ES) cell-derived NSCs and brain derived NSCs. NSCs from ES and iPS cells were morphologically indistinguishable from brain derived NSCs and stained positive for NSCs markers Nestin and Sox2. ES cells derived NSCs were transcriptionally distinguishable from brain derived NSCs. However, global gene expression pattern were similar but distinct between iPS derived NSCs and brain derived NSCs. Moreover, iPS derived NSCs were spontaneously aggregated upon passaging, formed ES cell like colonies, and finally reactivated Oct4-GFP. The spontaneously reverted GFP-positive cells (iPS-NSC-iPS) expressed similar levels of pluripotency markers (Oct4,Nanog) to ES and iPS cells, and could form germ line chimera. One possible explanation for this phenomenon is that spontaneously re-reprogramming was associated with transgene re-activation when iPS cells were differentiated into NSCs. However, NSCs from dox-inducible iPScells could not be reprogrammed into pluripotent state without doxycycline. Taken together, iPS derived NSCs were morphologically and similar to brain derived NSCs, but differ in gene expression pattern and maintenance. * This work was supported by the Next Generation Bio-Green21 Program funded by the Rural Development Administration (Grant PJ008009).
        150.
        2011.06 구독 인증기관 무료, 개인회원 유료
        Substantia gelatinosa (SG) neurons receive synaptic inputs from primary afferent Aδ- and C-fibers, where nociceptive information is integrated and modulated by numerous neurotransmitters or neuromodulators. A number of studies were dedicated to the molecular mechanism underlying the modulation of excitability or synaptic plasticity in SG neurons and revealed that second messengers, such as cAMP and cGMP, play an important role. Recently, cAMP and cGMP were shown to downregulate each other in heart muscle cells. However, involvement of the crosstalk between cAMP and cGMP in neurons is yet to be addressed. Therefore, we investigated whether interaction between cAMP and cGMP modulates synaptic plasticity in SG neurons using slice patchclamp recording from rats. Synaptic activity was measured by excitatory post-synaptic currents (EPSCs) elicited by stimulation onto dorsal root entry zone. Application of 1 mM of 8- bromoadenosine 3,5-cyclic monophosphate (8-Br-cAMP) or 8-bromoguanosine 3,5-cyclic monophosphate (8-Br-cGMP) for 15 minutes increased EPSCs, which were maintained for 30 minutes. However, simultaneous application of 8-BrcAMP and 8-Br-cGMP failed to increase EPSCs, which suggested antagonistic cross-talk between two second messengers. Application of 3-isobutyl-1-methylxanthine (IBMX) that prevents degradation of cAMP and cGMP by blocking phosphodiesterase (PDE) increased EPSCs. Co-application of cAMP/cGMP along with IBMX induced additional increase in EPSCs. These results suggest that second messengers, cAMP and cGMP, might contribute to development of chronic pain through the mutual regulation of the signal transduction.
        4,000원
        152.
        2011.05 구독 인증기관·개인회원 무료
        The Black pine bast scale, Matsucoccus thunbergianae is one of the most serious in black pine, Pinus thunbergii forests in Korea. Since this pest was first reported in Goheung, Korea in 1963, which is gradually spread into neighboring regions and now occurs in many regions of the southern and eastern part of the Korean peninsula. The monitoring for distribution of M. thunbergianae was able to observed by naked eye egg sacs and pupa of male on the host until now. Therefore, this monitoring was very difficult in the low density of M. thubergianae. This experiment was conducted to use simple and practical moving cross-shaped flat trap for monitoring of M. thunbergianae. The monitoring of M. thunbergianae using the device was carried out to southern regions of the Korean peninsula. The first emergence of male showed mid. March in Namhae and late march in Busan, Jinju and Pohang. The peak of emergence showed late March in Namhae and early April in the other regions. When the number of M. thunbergianae intermediate nymph showed 58~59, 11~44 and 8~25 on 39.25 ㎠ bark area of the black pine, Pinus thubergii for 1 week, the number of captured its male adult was 58~83, 67~488 and 1~55 on the moving cross-shaped flat trap (10× 13㎝), respectively. The low density of M. thunbergianae was some few the number of capture, but there were no significant difference in its high density. Also, the number of captured its male adult was no significant in the different color (yellow, red, white and blue) of the moving cross-shaped flat trap.
        159.
        2010.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 azoxymethane (AOM)과 dextran sodium sulfate (DSS)로 유도된 대장 발암과정에 대한 셀레늄의 방어 효과를 조사하였다. 셀레늄 결핍(0.02 ppm Se), 정상(0.1 ppm Se), 과다(0.5 ppm Se)사료를 12주간 식이로 급여하여 혈액검사와 대장암 발생의 초기단계인 aberrant crypt foci (ACF)수를 측정했으며, 암 발생율을 조사하였다. ICP-AES 를 사용하여 간의 셀레늄 농도를 측정하였으며, 또한 셀레늄포함 항산화효소인 glutathione peroxidase (GPx) 활성을 알아보았다. 또한 TUNEL assay와 PCNA, β-catenin에 대한 면역조직 염색을 수행하였다. ACF 수 및 종양 발생률에 있어서, 셀레늄과다사료를 급여한 군이 정상셀레늄사료를 급여한 군보다 낮았으며, 셀레늄결핍사료를 급여한 군은 오히려 ACF 수 및 종양 발생률이 높았다. GPx 활성은 셀레늄의 섭취가 과다한 군에서 높게 나타났으며, 이 때, TUNEL 에서 apoptotic positive cell이 증가하는 것을 확인했다. 또 한 셀레늄의 섭취가 과다한 군에서 PCNA와 β-catenin의 발현이 감소됨을 볼 수 있었다. 본 마우스 모델실험에서 셀레늄은 여러 기전에 의해 대장암 발생을 억제할 수 있을 것으로 사료된다.
        4,000원
        160.
        2010.05 구독 인증기관·개인회원 무료
        Our previous study demonstrated that Coprisin, a peptide from Copris tripartitus infected with bacterial pathogens, has an antibacterial activity. We assessed in this study whether Coprisin caused cellular toxicity in various mammalian cell lines. Coprisin selectively caused a marked drop of cell viability in Jurkat T cells, U937 cells and AML-2 cells belonging to the human leukemia cells but not in Caki cells and Hela cells. Fragmentation of DNA, a maker of apoptosis, was also confirmed in theleukemia cell lines but not in other cells. The Coprisin-induced apoptosis in leukemia cells was mediated by AIF (apoptosis inducing factor), a caspase -independent pathway.