• 천문학논총
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• 제27권4호
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• pp.285-286
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• 2012

We combine data from two all-sky surveys, the Swift/Burst Alert Telescope 22 Month Source Catalog and the AKARI Point Source Catalogue, in order to study the connection between the hard X-ray (> 10 keV) and infrared (IR) properties of local active galactic nuclei (AGN). We find two photometric diagnostics are useful for source classification: one is the X-ray luminosity vs. IR color diagram, in which type 1 radio-loud AGN are well isolated from other AGN. The second one uses the X-ray vs. IR color-color diagram as a redshift-independent indicator for identifying Compton-thick (CT) AGN. Importantly, CT AGN and starburst galaxies in composite systems can also be separated in this plane based upon their hard X-ray fluxes and dust temperatures. This diagram may be useful as a new indicator to classify objects in new surveys such as with WISE and NuSTAR.

• 한국미생물·생명공학회지
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• 제26권4호
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• pp.290-296
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• 1998

Alkaline protease 생산력이 우수한 야생형인 A. oryzae val. oryzae의 핵을 순수 분리하여 영양요구성 변이주인 P. chrysogenum(T$yr^{-}$)의 원형질체에 전달하는 핵전이를 이용하여 종간잡종을 형성시킨 후 이들 형질전환체으로 부터 alkaline protease 고생산 균주를 획득하였다. 핵전이를 위한 원형질체 형성 및 재생 조건에서는 Novozym 234의 농도 1%, 삼투안정제는 0.6 M KCl, 효 소의 처리 시간은 180분 그리고 최적 pH는 5.8로 나타났다. 핵전이에 의한 형질전환의 빈도는 1.3~3.8$\times$$10^{-4}$으로 비교적 낮은 편이었으며, 유전적 안정성, conidia의 크기, DNA함량의 측정 그리고 핵염색의 결과 형질전환체의 핵형은 aneuploid로 추정되었다. 형질전환체의 alkaline protease 활성은 모균주와 비교하여 1.1~2.2배 증가하였다.다.

• 한국균학회지
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• 제27권6호
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• pp.399-405
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• 1999

${\alpha}-amylase$ 생산력이 우수한 야생형인 S. fiburigera의 핵을 순수분리하여 영양요구성 변이주인 S. cerevisiae(tyr-, ura-)의 원형질체에 전달하는 핵전이를 이용하여 종간잡종을 형성시킨 후 이들 형질전환체로부터 ${\alpha}-amylase$ 고생산 균주를 획득하였다. 핵전이를 위한 원형질체 형성 및 재생조건에서는 Novozym 234의 농도 1%, 삼투안정제는 0.6M KC1, 효소처리 시간은 90분, 그리고 최적 pH는 5.8로 나타났다. 핵전이에 의한 형질전환율은 0.25%로 비교적 낮은 편이었으며, 유전적 안정성, 세포크기의 체적, DNA함량의 측정 그리고 핵염색의 결과 형질전환체의 핵형은 aneuploid로 추정되었다. 형질전환 체의 ${\alpha}-amylase$ 활성은 모균주와 비교하여 약 $1.2{\sim}1.9$배 증가하였다.

• 대한세포병리학회지
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• 제16권1호
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• pp.52-56
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• 2005

Fine-needle aspiration cytology (FNAC) has been used extensively in the diagnosis of metastatic malignancies. However, metastatic soft tissue sarcomas are often overlooked, primarily due to the low frequency with/ which they occur. Here, we report a rare case of metastatic rhabdomyosarcoma in both cervical lymph nodes, which was detected by FNAC. A 45-year-old woman presented with anosmia, postnasal drip, and sneezing, symptoms which had persisted for 1 month. The patient was found to have a tumorous lesion at the upper portion of the mid-turbinate, with multiple enlarged cervical lymph nodes, and this lesion was examined closely at our facility. FNA cytology smears obtained from both cervical lymph nodes revealed a high degree of cellularity, and displayed cohesive clusters with gland-like spaces, as well as single isolated cells with abundant karyorrhectic debris. The tumor cells exhibited round to oval nuclei containing fine chromatin, occasional small nucleoli, and scanty cytoplasm, or a total lack of cytoplasm. Some of the tumor cells were arranged in multinucleated forms and abundant dense eosinophilic cytoplasms, reminiscent of a rhabdomyoblast. The histological findings on the lymph nodes revealed an outstanding sinusoidal infiltration and a prominent alveolar growth pattern, interspersed with occasional typical rhabdomyoblasts. The immunohistochemical results [desmin (+), myoglobin (+), myogenin (+), pan CK (-), synaptophysin (-), neuron specific enolase (-)] supported a confirmative diagnosis of alveolar rhabdomyosarcoma. Alveolar rhabdomyosarcoma is a representative sarcoma, which typically manifests with nodal metastasis and carcinoma-like clustering. The cytopathologist should remain alert upon encountering unusual morphology, so that the possibility of this condition, although somewhat remote, should not be dismissed or overlooked.

• The Korean Journal of Physiology and Pharmacology
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• 제10권3호
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• pp.131-135
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• 2006

Coeruleo-vestibular pathway which connects locus coeruleus and vestibular nuclei is noradrenergic. This study was designed to elucidate the effects of phenylephrine on the spontaneous activity of acutely isolated medial vestibular nuclear neurons of rat by whole-cell patch-clamp technique. Sprague-Dawley rats, aged 14 to 16 days, were used. After enzymatic digestion, dissociated medial vestibular neurons were transferred to a recording chamber mounted on an inverted microscope, and spontaneous action potentials were recorded by standard patch-clamp techniques. In current-clamp mode, the frequency of spontaneous action potential of medial vestibular nuclear neurons was decreased by phenylephrine (n=15). Phenylephrine increased the amplitude of afterhyperpolarization without changes in the resting membrane potential and spike width. In voltage-clamp mode, the whole potassium currents of the medial vestibular nuclear neurons were increased by phenylephrine (n=12). These experimental results suggest that ${\alpha}-receptor$ mediates the inhibitory effects on the neuronal activity of the medial vestibular nuclear neuron.

• The Korean Journal of Physiology and Pharmacology
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• 제7권6호
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• pp.295-301
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• 2003

Striatum plays a crucial role in the movement control and habitual learning. It receives an information from wide area of cerebral cortex as well as an extensive serotonergic (5-hydroxytryptamine, 5-HT) input from raphe nuclei. In the present study, the effects of 5-HT to modulate synaptic transmission were studied in the rat corticostriatal brain slice using in vitro extracellular recording technique. Synaptic responses were evoked by stimulation of cortical glutamatergic inputs on the corpus callosum and recorded in the dorsal striatum. 5-HT reversibly inhibited coticostriatal glutamatergic synaptic transmission in a dose-dependent fashion (5, 10, 50, and $10{\mu}M$), maximally reducing in the corticostriatal population spike (PS) amplitude to $40.1{\pm}5.0$% at a concentration of $50{\mu}M$ 5-HT. PSs mediated by non-NMDA glutamate receptors, which were isolated by bath application of the NMDA receptor antagonist, d,l-2-amino-5-phospohonovaleric acid (AP-V), were decreased by application of $50{\mu}M$ 5-HT. However, PSs mediated by NMDA receptors, that were activated by application of zero $Mg^{2+}$ aCSF, were not significantly affected by $50{\mu}M$ 5-HT. To test whether the corticostriatal synaptic inhibitions by 5-HT might involve a change in the probability of neurotransmitter release from presynaptic nerve terminals, we measured the paired-pulse ratio (PPR) evoked by 2 identical pulses (50 ms interpulse interval), and found that PPR was increased ($33.4{\pm}5.2$%) by 5-HT, reflecting decreased neurotransmitter releasing probability. These results suggest that 5-HT may decrease neurotransmitter release probability of glutamatergic corticostriatal synapse and may be able to selectively decrease non-NMDA glutamate receptor-mediated synaptic transmission.

• 한국균학회지
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• 제17권3호
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• pp.154-160
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• 1989

핵전이 기술을 이용하여 Aspergillus nidulans에서의 종내잡종들을 얻어내고 이들의 섬유질 분해효소계 활성 및 핵형분석을 통하여 이 방법에 의한 균주개량의 가능성을 조사하였다. A. nidulans 야생균주와 영양요구성 돌연변이주 FGSC 475로부터 추출한 핵을 FGSC 514의 원형질체에 각각 전이시킨 결과 4.8% 및 10.1%의 잡종형성율을 나타냄으로써, 0.6%의 융합빈도를 보인 원형질체 융합법보다 핵전이법이 잡종형성에 더 효과적임을 알 수 있었다. 또한 형성된 잡종들에서 cellulase및 xylanase system과 mannanase 중 일부분의 효소성분의 활성이 향상된 균주가 분리되어 이 방법에 의한 우수 섬유질분해 균주개발의 가능성을 확인할 수 있었으며, 형성된 잡종의 핵형은 이배체 또는 이수체로 분석되었다.

• 대한핵의학회지
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• 제19권1호
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• pp.83-93
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• 1985

The ability of $^{67}Ga$, administered carrier free as the citrate complex, to localize in human and animal tumors to an extent sufficient to permit visualization of the lesion by scanning is well established. However, neither the mechanism of $^{67}Ga$ uptake by tumors or inflammatory cells nor its relationship to cell type or to the biochemical status of the cell is yet understood. Author investigated the uptake of $^{67}Ga-citrate$ using subcellular tissue fractionation of rat livers treated with $CCl_4$ associated with the $^3H-thymidine$ incorporation rate to detect subcellular localization of $^{67}Ga$ and it's relationship in DNA synthesis. Large amounts of $^{67}Ga$ associated with the soluble portion of tissue homogenate rather than with isolated cell organelles and not related nuclei residue in the regenerating period after hepatocellular injury caused by $CCl_4$. The elevated uptake of $^{67}Ga$ in the livers of $CCl_4$ treated rats was also inhibited when protein synthesis was stopped by cyclohexamide. Thus protein and the soluble portion of issue homogenates seems to play an important role in the elevated uptake of $^{67}Ga$ in liver injury induced by $CCl_4$ treated rats.

• Ocean and Polar Research
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• 제25권4호
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• pp.607-615
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• 2003

Many organisms are known to survive in icy environments. These include both over wintering terrestrial insects and plants as well the marine fish inhabiting high latitudes. The adaptation of these organisms is both a fascinating and important topic in biology. Marine teleosts in particular, can encounter ice-laden seawater that is approximately $1^{\circ}C$ colder than the colligative freezing point of their body fluids. These animals produce a unique group of proteins, the antifreeze proteins (AFPs) or antifreeze glycoproteins (AFGPs) that absorb the ice nuclei and prevent ice crystal growth. Presently, there are at least four different AFP types and one AFGP type that are isolated from a wide variety of fish. Despite their functional similarity, there is no apparent common protein homology or ice-binding motifs among these proteins, except that the surface-surface complementarity between the protein and ice are important for binding. The remarkable diversity of these proteins and their odd phylogenetic distribution would suggest that these proteins might have evolved recently in response to sea level glaciations just 1-2 million years ago in the northern hemisphere and 10-30 million years ago around Antarctica. Winter flounder, Pleuronectes americanus, has been used as a popular model to study the regulation of AFP gene expression. It has a built-in annual cycle of AFP expression controlled negatively by the growth hormone. The signal transduction pathways, transcription factors and promoter elements involved in this process have been studied in our laboratory and these studies will be presented.

• Journal of Microbiology
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• 제40권3호
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• pp.199-204
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• 2002

A microsporidium, from cabbage white bntteflies, Pieris rapae, collected in Korea, was purified and characterized according to its gene structure, spore morphology and pathogenicity. From the observation of the isolate by SEM and TEM, the endospores, exospores and nuclei, about 12 polar filament coils of the polar tube and posterior vacuoles were all identified. The nucleotide sequence was determined for a portion of genomic DNA which spans the V4 variable region of the small subunit rRNA gene. Comparison with the GenBank database for 15 other microsporidia species suggests that this isolate is most closely related to Nosema species. The pathogenicity against cabbage white butterflies was quantified by inoculating variable doses of spores to the second instar larvae. Peroral inoculation at a dosage of 10$\^$8/ spores/ml resulted in the death of all larvae prior to adult eclosion, but at lower spore dosages of 10$\^$4/-10$\^$5/ spores/ml, many adults successfully emerged. The median lethal dose (LD$\_$50/) was deter-mined to be 4.6$\times$10$\^$6/ spores/ml and the isolate also transmitted transovarially to the progeny eggs at a frequency of 92%.