• Journal of Microbiology and Biotechnology
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• 제17권11호
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• pp.1782-1788
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• 2007

Cellulosomes in Clostridium cellulovorans are assembled by the interaction between the repeated cohesin domains of a scaffolding protein (CbpA) and the dockerin domain of enzyme components. In this study, we determined the synergistic effects on cellulosic and hemicellulosic substrates by three different recombinant mini-cellulosomes containing either endoglucanase EngB or endoxylanase XynA bound to mini-CbpA with one cohesin domain (mini-CbpAl), two cohesins (mini-CbpA12), or four cohesins (mini-CbpAl234). The assembly of EngB or XynA with mini-CbpA increased the activity against carboxymethyl cellulose, acid-swollen cellulose, Avicel, xylan, and com fiber 1.1-1.8-fold compared with that for the corresponding enzyme alone. A most distinct improvement was shown with com fiber, a natural substrate containing xylan, arabinan, and cellulose. However, there was little difference in activity between the three different mini-cellulosomes when the cellulosomal enzyme concentration was held constant regardless of the copy number of cohesins in the cellulosome. A synergistic effect was observed when the enzyme concentration was increased to be proportional to the number of cohesins in the mini-cellulosome. The highest degree of synergy was observed with mini-CbpAl234 (1.8-fold) and then mini-CbpAl2 (1.3-fold), and the lowest synergy was observed with mini-CbpAl (1.2-fold) when Avicel was used as the substrate. As the copy number of cohesin was increased, there was more synergy. These results indicate that the clustering effect (physical enzyme proximity) of the enzyme within the mini-cellulosome is one of the important factors for efficient degradation of plant cell walls.

• International Journal of Industrial Entomology and Biomaterials
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• 제23권1호
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• pp.107-113
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• 2011

Infection effect of $Nosema$ $bombyics$ on the midgut of silkworm $Bombyx$ $mori$ and subsequent appearance of spores and the performance of larvae was studied. Autopsy of larvae showed white pustules on the surface of midgut at 5 days of post infection (pi). At later stage, important organs like midgut, silk gland and gonads reduced in size and all these organs showed white pustules. Light microscope observation of pustules revealed enormous spores. Spore multiplication was at a faster rate in young larvae. Infection of the adult larvae resulted in pebrinized pupa and moths. Larval weight, cocoon weight and cocoon shell ratio reduced as the post infection period increased. Transverse sections of midgut showed $N.$ $bombycis$ infection limited to a few columnar cells at 3-5 days of pi. At 7 days pi, cell volume increased, cells were swollen and elongated. Heavily infected cells looked like sacks filled with parasite and the apical region of certain cells were bulging into the gut lumen. Later at 8-9 days of pi, spores or its developing stages leaked into the lumen either freely or enclosed within the globules of host cytoplasm. Besides columnar cells, development of $N.$ $bombycis$ was observed in the regenerative cells and rarely in goblet cells. Development of $N.$ $bombycis$ was also observed in both longitudinal and circular muscles at the late pi period. The histopathological changes, deformities and spore production time in the host were all influenced by the spore dosage and age of the host.

• 한국응용곤충학회지
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• 제38권2호
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• pp.129-138
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• 1999

본 연구는 서로 다른 수명 패턴을 갖고 있는 누에성충 중 두가지 타입을 이용하여 수행되었다. 장명품종(성충 수명이 15일 이상; LLS), 단명 품종(성충 수명이 5일 미만;SLS). 누에성충의 노화 생리를 밝히기 위해 장단명 암수에 있어서의 지방체 미세구조를 비교해 보았다. 단명품종에 있어서는, 암컷에는 조면소포체 및 글리코겐 과립이 세포질내에서 다량 확인된 반면, 수컷에는 활면소포체만이 세포질내에서 발견되었다. 또한 단명품종에 있어서는, 성충 3일째 이후 미토콘드리아의 용적이 비대해지는 경향을 보였으며, 많은 지방구 퇴화가 관찰되었다. 단명품종에 반해 장명품종에서는, 성충 5일째의 암컷은 비교적 정상적인 미토콘드리아와 핵막이 관찰되었다. 성충 15일째에 이르러서야 대부분의 세포막이 사라졌고 미토콘드리아가 비정상적으로 비대해졌다. 장명품종 수컷(성충 10일째)의 세포질내에서 다량의 지방과립이 관찰되었으며, 이 개체는 성충 15일째에 세포내용물이 모두 고갈되어 사망하였다. 따라서, 금후 수명에 관한 조직 연구를 위해서는 조직의 변화상을 관찰하기 용이한 단명품종이 적절할 것으로 사료된다.

• Journal of Ginseng Research
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• 제16권3호
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• pp.222-227
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• 1992

Unlike carbohydrats and fats, alcohol is essentially foreign to the body and it is known that the body get rid of it by oxidizing alcohol maily in the liver. Acetaldehyde is produced during ethanol metabolism and is known to be oxidized mainly by aldehyde dehydrogenase (ALDH). ALDH activity was found mainly in the mitochondrial fraction but a significant ALDH activity was also present in microsomal and cytosol fraction. Wistar rats (150~200 g, male) were given freely with 12% ethanol (Control) and/or 12% ethanol containing 0.1% ginseng saponins (Test) instead of water for 6 days and the liver was analyzed. ALDH activities of both control and test group were lower than that of normal group but test AkDH was less inhibited than control. ADH activies of both control and test were slightly higher than that of normal group but our previous data showed that it became gradually steady after prolonged ethanol feeding. MEOS activities of both control and test group were much higher than that of normal group. MEOS enzymes are inducible but the activity of test group was greatly higher than that of control. Ethanol containing [1-i4C] ethanol (5 $\mu$Ci) was injected to the above three groups and 30 min later, the distribution of radioactivity of hepatic lipids was investigated. Radioactivities of hepatic lipids of both control and test group were higher than that of normal group, however, that of test group was much lower than that of control. Analysis of individual lipids showed that phospholipid biosynthesis was significantly impaired and fatty acid and triglycerides biosynthesis were greatly stimulated. However, it was realized that the saponin prevented phospholipid biosynthesis depression and the increase of triglyceride biosynthesis considerably. It seemed that the saponin might stimulate ADH, ALDH and MEOS and the acetaldehyde formed would be removed faster. The excess hydrogen can be shunt more quickly into lipid biosynthesis. Electron microscopic observation showed that the hepatic cell of control group was si gnificantly damaged. Mitochondria were swollen and rough endoplasmic reticulum were dilated, however, hepatocytes of test group were not damaged.

• 한국어류학회지
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• 제28권4호
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• pp.223-228
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• 2016

한국산 대륙송사리 Oryzias sinensis의 후각기관을 실체현미경과 광학현미경을 이용하여 해부 및 조직 화학적 특징들을 조사하였다. 전체적 구조에서 후각기관은 두부의 주둥이 위에 한 쌍으로 존재하였으며 다소 떨어져있는 전비공과 후비공, 한 개의 비강, 한 개의 비낭으로 구성되었다. 비강내 상피는 감각상피와 비감각상피층으로 구분되었다. 감각상피는 후감각세포, 지지세포, 기저세포 그리고 공포들로 구성되었다. 비감각상피는 층상상피 세포, 산성과 중성 점액세포들로 구성되었다. 비낭의 상피층은 층상상피세포와 배상세포들로 구성되었다. 결과적으로 이러한 대륙송사리의 후각기관의 해부 및 조직화학적 특징들은 농경지에서의 정체되고 오염되어있는 수환경을 반영하는 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제17권2호
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• pp.262-270
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• 2007

Of the twelve lytic bacteriophages recovered from five different fermenting cucumber tanks that were inoculated with Pediococcus sp. LA0281, a lytic phage, ${\phi}ps05$, was characterized in the present study. The plaques were mostly clear and round-shaped on the lawn of starter strain, indicating lytic phage. Overall appearance indicated that it belongs to the Siphoviridae family or Bradley's group B1, with a small isometric head and a flexible noncontractile tail with swollen base plate. The average size was found to be 51.2 nm in head diameter and 11.6 nm wide ${\times}$ 129.6 nm long for the tail. The single-step growth kinetics curve showed that the eclipse and the latent period were 29 min and 34 min, respectively, and an average burst size was calculated to be 12 particles per infective center. The optimum proliferating temperature ($35^{\circ}C$) was slightly lower than that of cell growth ($35\;to\;40^{\circ}C$). The structural proteins revealed by SDS-PAGE consisted of one main protein of 33 kDa and three minor proteins of 85, 58, and 52 kDa. The phage genome was a linear double-stranded DNA without cohesive ends. Based on the single and double digestion patterns obtained by EcoRI, HindIII, and SalI, the physical map was constructed. The overall size of the phage genome was estimated to be 24.1 kb. The present report describes the presence of a lytic phage active against a commercial starter culture Pediococcus sp. LA0281 in cucumber fermentation, and a preliminary study characterizes the phage on bacterial successions in the process of starter-added cucumber fermentation.

• 미생물학회지
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• 제22권4호
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• pp.207-214
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• 1984

2-deoxy-D-glucose가 첨가된(25 pg/ml) 최소액체 배지에 8.5시간 전 배양하여 swelling 시킨 conidiospore에 2% driselase와 2% ${\beta}-glucuronidase$를 동량 혼합한 효소용액을 처리하여 반응시킨 결과 protoplast형성 시간 2시간이내로 단축 시킬 수 있었다. 5% Ficoll(m.w. 400,000)용액을 사용하여 conidial protoplast를 보다 순수하게 분리 벙제할 수 있었으며, protoplast를 Giemsa로 핵 염색한 결과, 대부분의 protoplast는 하나의 핵을 갖고 있었다. 또한 전자현미경으로 관찰한 결과 conidiospore에서 유래된 protoplast는 세포벽 성분이 남아 있지 아니한 완전한 protoplast인 것으로 판명되었다. 영양요구성 돌연변이주에서 유래된 conidial protoplast의 융합률은 $3.4{\times}10^{-1}$에서 $4.9{\times}10^{-1}$수준으로 이는 mycelial protoplast의 경우보다 5-28배 가량 높은 수준의 것이었다.

• Applied Microscopy
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• 제22권2호
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• pp.1-14
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• 1992

This experiment was performed to study the morphological responses of the parafollicular cells of rat following X-ray irradiation. Male rats were divided into normal and experimental groups. The head and neck region of the rat, under sodium thiopental anesthesia, was exposed to 3,000 rads or 6,000 rads of radiation in a single dose, respectively. The source was a Mitsubishi Linear Accelerator ML-4MV. The target to skin distance was 80 cm, and the dose rate was 200 rads/min. The rate of experimental groups were sacrificed on the 6th hour, 2nd and 6th day after X-ray irradiation. Pieces of the tissue taken from the thyroid gland were fixed in 2.5% glutaraldehyde-1.5% paraformaldehyde (0.1M Millonig's phosphate buffer, pH 7.3), and in 1% osmium tetroxide (0.1M Millonig's phosphate buffer, pH 7.3), and embedded in araldite mixture. The ultrathin sections stained with uranyl acetate and lead citrate were observed with JEM 100 CX-II electron microscope. The results were as follow; 1. Two types of the parafollicular cells, according to their electron densities, were found, i. e., light cells and dark cells. 2. Three types of the parafollicular cells, according to their sizes of secretory granules were found, i.e., small granule cells ($85nm{\pm}20.1;64{\sim}102nm$), medium granule cells ($120nm{\pm}26.5;77{\sim}179nm$), and large granule cells ($165nm{\pm}25.7;128{\sim}189nm$). 3. The differential ultrastructural changes of the cells according to their cell types, i.e., dark and light cell, or small, medium and large granule cells, were hardly observed in the time and dose range covered by this study. 4. The morphological changes of the parafollicular cells were not pronounced after exposure to 3,000 rads of X-ray. 5. Swollen cisternae of the granular endoplasmic reticulum and partial cytolysis were observed after exposure to 6,000 rads of X-ray. 6. Above results suggest that the parafollicular cells showed the alterations of mitochondrial and granular endoplasmic reticular swelling, and partial cytolysis, but only in doses of 6,000 rads.

• Applied Biological Chemistry
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• 제42권1호
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• pp.12-19
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• 1999

Biopolymer를 생산하는 Bacillus subtilis K-1과 유당 이용능이 있는 Bacillus coagulans를 융합시켜 획득된 융합주에 의해 생산된 biopolymer의 특성 변화, 생산성 향상의 연구의 일환으로 두균주의 융합을 시도하였고 융합주의 특성을 조사하였다. 원형질체 융합은 33% PEG(Mw. 6,000), 1% PVP, 10 mM $CaCl_2$이 함유된 fusion fluid(FF)에서 5분간 반응하였고, 항생제가 함유된 선별배지에 중층 후, 3일간 배양했을 때 Bacillus subtillus coagulans 변이주 들간의 융합빈도는 $4.6{\times}10^{-5}{\sim}1.8{\times}10^{-7}$이었다. 융합주의 세포특성 검토에서 분리된 모든 융합주의 segregation 비는 $1{\sim}6%$로 나타나 유전적으로 안정하였고, 각 균주가 요구하는 영양 요구성 marker와 항생제의 함유배지에서 생육이 확인되었다. 주요 융합주의 DNA함량은 모균주보다 $1.6{\sim}2.7$배 높게 나타났다. 융합주의 전자현미경 관찰에서두 모균주는 간상체로서 두꺼운 세포벽과 이중막을 확인할 수 있었고 원형질체 형성과정에서 팽융된 세포에서 구형의 원형질체 방출이 이루어지고, 원형질체 융합과정 및 형성된 융합체에서 융합체내 전형적인 vesicle이 확인되었으며 모균주보다는 큰 형태의 세포를 확인할 수 있었다.

• 한국임상수의학회지
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• 제8권2호
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• pp.127-142
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• 1991

This study was carried out to investigate fatty liver in Korean black goats. Adult female goats were divided into 3 test groups(A, B and C). Group A and B of goats each received 3 test consecutive daily doses of DL-ethionine at 75mg/kg and 150mg/kg body weight, respectively. Group C of goats was given 3 consecutive doses of the compound every 48 hours at 150mg/kg body weight. The clinical symptoms, hematological values, serum chemical values and histopathological study of the liver were investigated in the test animals. The results obtained are as follows ; 1. Fatty liver were observed in every test animal. 2. Some clinical symptoms( anorexia, depression) were appeared from 1st day to 7th day after administration of the compound in every test animal. In addition to these symptoms, diarrhea and salivation were generally observed in test animals which were given the compound at 150mg/kg body weight. The degree of these symptoms was dose dependent. 3. There was no significant variations in total WBC counts and fibrinogen values in the blood of test goats. The PCV values were significantly increased on 5th day of dosing in group A and B of goats. 4. The total lipid value was not changed but the concentration of NEFA was significantly increased on 3rd day of dosing with the compound and returned to normal value after 10 days hereafter. The value of triglycerides was significantly increased on 1st day and returned to normal value on 3rd day of dosing. The value of cholesterol was significantly decreased on 3rd day and returned to normal value on 10th day after treatment. 5. Total protein level was decreased on 10th day of dosing in the groups of B and C, and billirubin level was significantly increased on 7th day of dosing in every test group and returned to normal level after 13th day of administration. 6. The activity of GGT in serum was not changed while the activities of SDH and AST were significantly increased in every test goat and those values were returned to normal after 10~13th day of trestment. 7 The 35K-protein fraction in serum was not detected by SDS-polyacrylamide gel electrophoresis, but this protein fraction was detected by the same method after treating the 21st and 22nd fraction which were obtained by column chromatography with Sephadex G-100. 8. The affected liver was congested and swollen on 3rd day, and yellowish brown in color and mottled appearance on 7th day of treatment. Histopathologically, fat droplets were common in the hepatocytes, this change was intensive on 7th day after treatment in group B and C. Hepatic cell necrosis was observed in some livers but this pathological change was disappeared and returned to normal after 13 days of treatment.