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Chemical Structures and Physiological Activities of Plant Growth Substance, Malformin B's (식물생장조절물질 말포민 B동족체의 화학구조 및 생리활성)

  • Kim, K.W.
    • Korean Journal of Weed Science
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    • v.15 no.1
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    • pp.85-98
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    • 1995
  • Six malformin B's produced by Aspergillus niger van Tiegh. were separated by HPLC. Their structures determined by the methods of amino acid analyses, mass spectrometry, and two-dimensional NMR were revealed as cyclic pentapeptides structurally related to malformin $A_1$. Both the NMR and MS/MS data suggest that the respective structures of separated malformin B's were as follows; cyclo-D-Cys-D-Cys-L-Val-D-Leu-L-allo-Ile for $B_{1a}$, cyclo-D-Cys-D-Cys-L-Val-D-Leu-L-Leu for $B_{1b}$, cyclo-D-Cys-D-Cys-L-Val-D-Val-L-Leu for $B_2$, cyclo-D-Cys-D-Cys-L-Val-D-Ile-L-Leu for $B_3$, cyclo-D-Cys-D-Cys-L-Val-D-Ile-L-Ile for $B_4$, and cyclo-D-Cys-D-Cys-L-Val-D-Val-L-Ile for $B_5$. Among the malformin B's, the structure of $B_{1b}$ was the same as that of malformin $A_3$ or C. All the malformin B's showed physiological activities in the two assay systems using corn(Zea mays L.) roots and mung bean(Phaseolus aureus Roxb.) hypercotyl segments. The malformin B's with molecular weight 529 were more effective for inducing corn root curvature than those with molecular weight 515. The difference in molecular weight of malformin B's, i.e., the retention time on HPLC, results in the polarity change of the whole malformin molecule which affects the revealation of the malformin activities. In addition, the disulfide form of the malformin B's gives the rigidity of the molecule, whereas the combination of the fourth and the fifth amino acid residues provides the optimal three-dimensional configuration to the malformin receptor of plants. Presumably, these two factors are appeared to be essential for the greatest physiological activity of malformin B's. malformin $B_{1a}$ caused the corn root curvature by 90% at a concentration of $0.25{\mu}M$. However, such differential activities with molecular weight of 529 or 515 of malformin B's were not found in the mung bean hypercotyl segment test. Maximum stimulation of mung bean hypercotyl growth was observed at $0.1{\mu}M$ concentration of malformin B's. The growth of the segments treated with $B_5$ was 154% greater than that of the control.

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Effects of BCG on Gastric Chief Cells of the Mouse Implanted with Ehrlich Carcinoma Cells (BCG가 Ehrlich 암세포를 이식한 생쥐 위점막 으뜸세포의 미세구조에 미치는 영향)

  • Ryoo, In-Sang;Ahn, E-Tay;Park, Kyung-Ho;Park, Dae-Kyoon;Kim, Myeong-Soo;Ko, Jeong-Sik
    • Applied Microscopy
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    • v.35 no.3
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    • pp.153-163
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    • 2005
  • This experiment was performed to evaluate the morphological responses of the gastric chief cells of the mouse, inoculated with Ehrlich carcinoma cells in the inguinal area, following administration of BCG (Bacillus Calmette-Guerin). Healthy adult ICR mice weighing 25 gm each were divided into normal and experimental groups (experimental control group and BCG treated group). In the experimental groups, each mouse was inoculated with $1x10^7$ Ehrlich carcinoma cells subcutaneously in the inguinal area. From next day after inoculations, 0.2 mL of saline or BCG (0.5 mL/25 g B.W.: $0.03{\times}10^8{\sim}0.32{\times}10^8$ CFU) were injected subcutaneously to the animals every other day, respectively. The day following the last injection, each mouse was sacrificed. Pieces of the tissue were taken from the stomach, prefixed with 2.5% glutaraldehyde-1.5% paraformaldehyde solution, followed by post-fixation with 1% osmium tetroxide solution. The ultrathin sections were stained with uranyl acetate and lead citrate. The size of zymogen granule and the size of the mitochondrion of the gastric chief cells were observed and calculated. In the BCG treated group, most chief cells did not show any difference in ultrastructure, except that myelin figures were more frequently observed, in comparison with that of nornmal control group. The size of zymogen granule in the gastric chief cells of normal control, experimental control and BCG-treated groups were $0.98({\pm}0.108){\mu}m,\;1.05({\pm}0.092){\mu}m\;and\;0.93({\pm}0.053){\mu}m$, respectively. And the mitochondrial size of the gastric chief cells of normal control, experimental control and BCG-treated groups were $0.80({\pm}0.130){\mu}m,\;0.83({\pm}0.143){\mu}m\;and\;0.72({\pm}0.078){\mu}m$, respectively. From the above results, it was concluded that BCG may slightly suppress function of the gastric chief cells.

식품과 알레르기: 유전자 재조합 식품의 알레르기 위험성

  • 손대열
    • Proceedings of the Korean Journal of Food and Nutrition Conference
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    • 2000.12a
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    • pp.29-34
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    • 2000
  • 산업 발달에 따라 날로 많은 식품들이 새롭게 개발되어지고 있다. 또한 이와 병행해서 식품으로 인한 알레르기 발생 빈도도 날로 증가하고 있으며 그 증상 또한 점차 심화되고 있는 것이 세계적인 추세이다. 우리나라도 예외는 아니어서 일반 알레르기 환자뿐 아니라 식품으로 인한 알레르기 환자들이 점차 증가됨이 보고되어지고 있다. 농산물 시장의 수입개방이후 우리나라에는 많은 해외 농산물이 수입되어지고 있으며 그 중 작년 한해의 경우 총 수입 농산물의 10%를 넘는 유전자 재조합 농산물이 우리나라에 수입되어진 것으로 통계 보고되어졌다. 이러한 관점에서 알레르기 환자의 증가와 새로운 식품 (특히 유전자 재조합 식품)의 증가에는 서로 관련성이 있을 것으로 추측되어지고 있어 (새로운) 식품에 대한 알레르기성의 예측과 관리가 필요한 실정이다. 이에 몇몇 발표된 유전자 재조합 식품에 관련된 알레르기성 검사 논문들과 실험실에서 이루어진 연구 결과들을 중심으로 유전자 재조합 식품의 알레르기 위험성에 대해 알아보고자 한다. 일반적으로 식품의 단백질이 알레르겐(allergen)으로 작용하기 위해서는 먼저 소화효소에 의해 분해되어지고 장에서 흡수되어져서 immunopotent cell에 의해 process 되어 immune system에 present 되어져야 한다. 따라서 단백질로 인한 알레르기 반응은 그 단백질의 자연적 형태 뿐만이 아니라 소화 효소에 분해된 단편들의 구조 또는 다른 알레르겐 단백질과의 유사 구조로 인한 교차 반응에 의해 발생함을 기억해야 한다. 식품 단백질 중 어떤 단백질이 알레르겐으로 작용하는가에 대한 특이성 조사에 많은 관심이 집중되어지고 있지만 아직까지는 대략 다섯 개 정도의 일반적인 특성으로서 요약되어질 수 있다. 그러나 이러한 대략의 특성에 적용되지 않는 식품 알레르겐도 많음을 잊어서는 안 될 것이다. 알레르겐으로 작용하는 식품 단백질의 일반적 특성 1. 좋은 수용성 2. 식품내에 많은 부분을 차지하는 주 단백질이 주 알레르겐으로 작용 3. 단백질내에 하나 이상의 IgE-binding site 존재 4. 위장액에 대한 저항성 5. 10~70 kDa 크기 유전자 재조합 기술이란 말 그대로 유전자를 인위적으로 새롭게 조합하는 기술로 이전의 기술로는 불가능했던 유전적 변형을 농작물과 동물에 가능하게 했으며 이로 인해 유전적으로 변형된 식용 동식물의 개발이 가능하게 되었다. 새로운 유전인자를 개체에 삽입함으로 새로운 단백질이 발현 될수 있고 그로 인해 1) 해충과 질병에 대한 저항성 증가, 2) 화학 제초제에 대한 새로운 저항성 부여, 3) 식품의 저장성 향상, 4) 식품의 영향적 보충/향상 등의 이점을 얻을 수 있다 (표 1). 세계적으로 유전자 재조합 된 새로운 농산물의 재배는 날로 증가추세에 있으며 그 중에서 가장 많은 부분을 차지하는 농산물로 soybean을 들 수 있으며 (표 2) soybean을 중심으로 그 알레르기성의 변화가 연구 조사된 몇 가지 예를 살펴보고자 한다. (표 3)에 요약된 soybean중 첫 번째 경우는 재초제에 대한 저항성을 높여주기 위해 Agrobacterium에 존재하는 EPSPS라는 단백질을 콩에서 발현하도록 찬 유전자 재조합 된 콩의 경우이다. 이 콩의 경우에는 첫째. 이전된 새로운 단백질 EPSPS가 다른 여러 식물에 이미 존재하고 있는 단백질로서 우리가 이미 이러한 식품을 섭취할 때 이 단백질도 같이 섭취해오고 있었다는 점, 둘째. 이 단백질이 소화액 분해 실험에서 짧은 시간내에 분해가 되었다는 점, 셋째. 재조합 된 콩과 자연 콩이 성분 분석에서 차이를 나타내지 않았다는 점, 네 번째. 쥐를 통한 다양섭취 실험에서 아무런 이상 반응이 없었다는 점등의 결과를 기준으로 알레르기에 대한 개별 검사 없이 안전한 콩으로 결론짓고 있다. 영양성을 높이기 위해 Brazil nut에서 methionine 함량이 풍부한 2s albumine을 콩에서 발현하도록 한 두 번째 유전자 재조합 콩의 경우 이전된 단백질 때문에 Brazil nut에 알레르기 반응을 일으키는 알레르기 환자들을 조사한 결과 역시 재조합 된 콩에도 알레르기 반응을 일으켰다는 보고이다. Brazil nut에서 콩으로 이전된 단백질이 Brazil nut에서의 알레르기성을 그대로 유지한 점을 볼 때 새로운 단백질이 어디에서 유래하는가가 중요함을 잘 보여준 연구이다 세 번째 콩의 경우 역시 영양성을 높여주기 위해 corn에서 10 kDa과 HSZ 단백질을 콩에서 발현하도록 유전자 재조합했는데 이 콩의 경우는 알레르기 환자들이 유전자 재조합 된 콩과 자연 콩에 반응의 차이를 나타내지 않았다는 결과 보고이다. 위의 세 실험 결과들을 종합해 볼 때 무엇보다도 새롭게 발현된 단백질이 원래 어떤 성질을 갖고 있으며 어디에서 유래했는지가 알레르기성 조사에 중요한 역할을 한다 할 수 있겠다. 또한 유전자 재조합된 식품들은 알레르기 환자들을 위해 표기되어져야 할 것인데 이를 위한 알레르기성 검사 실험은 공공단체를 통해 이루어져야 할 것이며 환자들마다 알레르겐으로 작용하는 단백질의 인식부위(epitope)가 다를 수 있기 때문에 적어도 10명 이상의 알레르기 환자들이 조사되어져서 검사가 이루어져야 할 것이다. 환자들의 혈청을 통한 in vitro 실험에서는 ELISA, RAST, immunoblotting과 같은 검사 방법들이 적용될 수 있고, 그 결과가 음성인 경우에 그 다음 단계로 in vivo 실험에서는 직접 환자의 피부반응검사 (skin prick test)나 DBPCFC (double-blind placebo-controlled food challenge) 검사 방법을 통해 확인되어져서 이 모든 경우가 음성인 경우와 하나라도 양성인 경우를 구별하여 식품에 표기함으로 알레르기 환자들의 유전자 재조합 식품에 대한 안전성이 보장되어져야 할 것이다.

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Enhancement of Fertilizing Ability of Frozen-Thawed Bovine and Human Spermatozoa Treated with Fertilizing Promoting Peptide or Pentoxifylline (Fertilizing Promoting Peptide와 Pentoxifylline으로 처리된 소와 사람 동결 정액의 수정능 향상)

  • Lee, K.S.;Kim, E.Y.;Park, S.Y.;Shin, H.A.;Park, S.P.;Lim, J.H.;Chung, K.S.;Lee, H.T.
    • Korean Journal of Animal Reproduction
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    • v.25 no.4
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    • pp.409-419
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    • 2001
  • This study was to examine whether the in vitro friability, motility and intact acrosome of frozen-thawed bovine and human sperm can be improved by adding Pentoxifylline (PF) or Fertilization Promoting Peptide (FPP). Human semen was frozen ultra-rapidly using Test yolk-buffer (TYB) freezing medium. Additive (PF, FPP) effects in frozen-thawed bovine and human sperm were analyzed by microscopic count for sperm motility and coomassie brilliant blue staining method f3r sperm acrosome intact. The in vitro motility of frozen-thawed bovine sperm with 5 mM PF treatment group (50.0%) was significantly higher than that of control (34.0%) (P<0.05). In the frozen-thawed bovine sperm was examined, the intact acrosome rate of 50 nM FPP treatment (49.0%) was significantly higher than those of control (30.0%) and 25 nM FPP (38.0%) treatment groups (P<0.01). In human semen, when in vitro motility of sperm with PF addition prior to freezing was examined, the result of 5 mM treatment group (51.0%) was significantly higher than those of control and 2.5 mM treatment group (39.0, 40.0%) (P<0.01). In addition, 50 nM (75.5%) FPP adding in all treatment procedures for human semen freezing (before freezing, freezing and after thawing) was significant effect on maintenance of the sperm intact acrosome percentage (control: 45.0; 25 nM: 53.0; 100 nM: 68.0%) (P<0.01). Also, the intact acrosome rate of human sperm with FPP (65.0%) was significantly higher than that with PF (43.0%) (P<0.05), although sperm motility was slightly higher in PF treatment group. These results suggest that improved sperm motility and intact acrosome of frozen thawed bovine and human sperm can be obtained by addition of PF or FPP, and that the enhanced in vitro viability, motility and intact acrosome can be obtained by addition of FPP in all semen freezing procedures.

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Neutralization of Pyrophyllite Mine Wastes by the Lime Cake By-Product (부산석회를 이용한 납석광산 폐석의 중화처리)

  • Yoo, Kyung-Yoal;Cheong, Young-Wook;Ok, Yong-Sik;Yang, Jae-E.
    • Korean Journal of Environmental Agriculture
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    • v.24 no.3
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    • pp.215-221
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    • 2005
  • Numerous abandoned or closed mines are present in the steep mountain valleys in Korea due to the depression of the mining industry since the late 1980s. From the mines, enormous amounts of wastes were dumped on the slopes causing sedimentation and acid mine drainage to be discharged directly into streams causing detrimental effects on surrounding environment. Objective of this research was to evaluate the feasibility of the lime cake by-product from the soda ash production (Solvay process) to neutralize the pyrophyllite mine wastes, which have discharged the acid drainage to soil and stream in the watershed. The pH of mine wastes was strongly acidic at pH 3.67 containing over 16% of $Al_2O_3$ and 11% of $Fe_2O_3$. Whereas the lime cake by-product was strongly basic at pH 9.97 due to high contents of CaO, MgO and $CaCl_2$ as major components. Column experiments were conducted to test the neutralizing capacity of the lime cake by-product for the acidic pyrophyllite mine wastes. The column packed with the wastes (control) was treated with the lime cake by-product, calcium carbonate, the dressing soil or combination. The distilled water was eluted statically through the column and the leachate was collected for the chemical analyses. Treatments of the mine wastes with the lime cake by-product (or calcium carbonate) as mixtures increased pH of the leachate from $3.5{\sim}4.0\;to\;7{\sim}8$. Concentrations of Fe and Al in the leachate were also decreased below 1.0 mg $L^{-1}$. A Similar result was observed at the combined treatments of the mine waste, the lime by-product (or calcium carbonate) and the dressing soil. The results indicated that the lime cake by-product could sufficiently neutralize the acid drainage from the pyrophyllite mine wastes without dressing soils.

A Case of Childhood Obstructive Sleep Apnea Syndrome with Co-morbid Attention Deficit Hyperactivity Disorder Treated with Continuous Positive Airway Pressure Treatment (지속적(持續的) 상기도(上氣道) 양압술(陽壓術)을 시행(施行)하여 치료효과(治療效果)를 본 주의력(注意力) 결핍(缺乏).과잉(過剩) 운동장애(運動障碍)를 동반(同伴)한 소아기(小兒基) 폐쇄성(閉鎖性) 수면무호흡증(睡眠無呼吸症) 1례(例))

  • Sohn, Chang-Ho;Shin, Min-Sup;Hong, Kang-E;Jeong, Do-Un
    • Sleep Medicine and Psychophysiology
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    • v.3 no.1
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    • pp.85-95
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    • 1996
  • Obstructive sleep apnea syndrome(OSAS) in childhood is unique and different n-om that in adulthood in several aspects, including pathophysiology, clinical features, diagnostic criteria, complications, management, and prognosis. Characteristic features of childhood OSAS in comparison with the adult form are the variety of severe complications such as developmental delay, more prominent behavioral and cognitive impairments, vivid cardiovascular symptoms, and increased death risk, warranting a special attention to the possible diagnosis of OSAS in children who snore. However, the childhood OSAS is often neglected and unrecognized. We, therefore, report a case of very severe OSAS in a 5-year-old boy who was sucessfully treated with continuous positive airway pressure(CPAP) treatment. Interestingly, the patient was comor-bid with the attention deficit hyperactivity disorder. Prior to the initial visit to us, adenotonsillectomy had been done at the age of 4 with no significant improvement of apneic symptoms and heavy snoring. On the initial diagnostic procedures, marked degree of snoring was audible even in the daytime wake state and the patient was observed to be very hyperactive. Increased pulmonary vascularity with borderline cardiomegaly was noted on chest X-ray. The baseline polysomnography revealed that the patient was very sleep-apneic and snored very heavily, with the respiratory disturbance index(RDI) of 46.9 per hour of sleep, the mean SaO2 of 78.8%, and the lowest SaO2 of 40.0%(the lowest detectable oxygen level by the applied oxymeter). The second night polysomnography was done for CPAP titration and the optimal pressure turned out to be $8.0\;cmH_2O$. The applied CPAP treatment was well tolerated by the patient and was found to be very effective in alleviating heavy snoring and severe repetitive sleep apneas. After 18 months of the CPAP treatment, the patient was followed up with nocturnal polysomnography(baseline and CPAP nights) and clinical examination. Sleep apneas were still present without CPAP on the baseline night. However, the severity of OSAS was significantly decreased(RDI of 15.7, mean SaO2 of 96.2%, and the lowest SaO2 of 83.0%), compared to the initial polysomnographic findings before initiation of long-term CPAP treatment. Wechsler intelligence tests done before and after the CPAP treatment were compared with each other and surprising improvement of intelligence(total 9 points, performance 16 points) was noted. Clinically he was found to be markedly improved in his attention deficit hyperactive behavior after CPAP treatment, but with minimal change of TOVA(test of variables of attention) scores except conversion of reaction time score into normal range. On the chest X-ray taken after 18 months of CPAP application, the initial cardiopulmonary abnormalities were not found at all. We found that the CPAP treatment in a young child is very effective, safe, and well-tolerated and also improves the co-morbid attention deficit hyperactive symptoms. Overall, the growth and development of the child has been facilitated with the long-term use of CPAP. Cardiovascular complications induced by OSAS have been also normalized with CPAP treatment. We suggest that early diagnosis and active treatment intervention of OSAS in children are crucial in preventing and ameliorating possible serious complications caused by repetitive sleep apneas and consequent hypoxic damage during sleep.

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The Clinical Significance of Serum CD23 and CD25 in Chronic Cough Patients (만성 기침환자에서 혈청 CD23와 CD25 측정의 임상적 의의)

  • Choi, Jae-Chol;Park, Young-Bum;Jee, Hyun-Suk;Kim, Jae-Yeol;Park, In-Won;Choi, Byoung-Whui;Hue, Sung-Ho
    • Tuberculosis and Respiratory Diseases
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    • v.48 no.4
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    • pp.471-477
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    • 2000
  • Background : Coughing is the most common complaint for which patients seek medical service. When caughing continues over 3 weeks in non-smokers who do not take cough-provoking drugs, they are classified as patients with chronic cough. Three well known main causes of chronic caugh are postnasal drip syndrome, bronchial asthma and gastroesophaseal reflux disease. Among them, postnasal drip syndrome is reported to be the most common cause of all in chronic cough diseases, and allergic inflammation plays an important role in the pathogenesis of postnasal drip syndrome. CD23 and CD25 which are low affinity receptor for IgE and IL-2 receptor alpha, respectively, are closely related to allergic inflammation and their roles were evaluated in chronic cough patients. Methods : We evaluated 105 patients with chronic cough and selected 56 patients for measurement of serum CD23 & CD25 levels. We selected 10 normal, medical students for comparison of serum CD23 & CD25 levels. Result : The postnasal drip syndrome was found to be the most common cause of chronic cough. Serum CD23 and CD25 did not increase in chronic cough patient compared to normal controls. However in bronchial asthma patient, serum CD23 level was increased relative to normal control (p<0.05). Conclusion : In bronchial asthma presented as chronic cough, lymphocyte mediated allergic inflammation may related with the pathogenesis of the disease.

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Influence of the Increase of Dissolved $CO_2$ Concentration on the Marine Organisms and Ecosystems (해수중 용존 $CO_2$ 농도 증가가 해양생물 및 해양생태계에 미치는 영향: 국내외 사례 연구)

  • Lee, Jung-Suk;Lee, Kyu-Tae;Kim, Chan-Kook;Park, Gun-Ho;Lee, Jong-Hyeon;Park, Young-Gyu;Gang, Seong-Gil
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.9 no.4
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    • pp.243-252
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    • 2006
  • Influence of the increasing carbon dioxide concentration in seawater on various marine organisms is assessed in this article with regard to the impacts of anthropogenic $CO_2$ introduced into surface or deep oceans. Recent proposals to sequester $CO_2$ in deep oceans arouse the concerns of adverse effects of increased $CO_2$ concentration on deep-sea organisms. Atmospheric introduction of $CO_2$ into the ocean can also acidify the surface water, thereby the population of some sensitive organisms including coral reefs, cocolithophorids and sea urchins will be reduced considerably in near future (e.g. in 2100 unless the increasing trend of $CO_2$ emission is actively regulated). We exposed bioluminescent bacteria and benthic amphipods to varying concentrations of $CO_2$ and also pH for a short period. The ${\sim}l.5$ unit decrease of pH adversely affected test organisms. However, amphipods were not influenced by decreasing pH when HCl was used for the seawater acidification. In this article, we reviewed the biological adverse effects of $CO_2$ on various marine organisms studied so for. Theses results will be useful to predict the potential risks of the increase of $CO_2$ concentrations in seawater due to the increase of atmospheric $CO_2$ emission and/or sequestration of $CO_2$ in deep oceans.

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Sister Chromatid Exchange (SCE) Frequency and In Vitro Development of Mouse Zygote Cryopreserved by Vitrification (초자화 동결에 의한 생쥐 1-세포기배의 체외 발달과 SCE 빈도)

  • Kim, M.K.;Baik, C.S.;Uhm, S.J.;Kim, E.Y.;Yoon, S.H.;Park, S.P.;Chung, K.S.;Lim, J.H.
    • Clinical and Experimental Reproductive Medicine
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    • v.23 no.3
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    • pp.379-384
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    • 1996
  • This study was undertaken to investigate the sister chromatid exchange (SCE) frequency and embryonic development after exposure to cryoprotectants and vitrification of mouse zygotes. Mouse IVF zygotes were cryopreserved by vitrification using vitrification solution, EFS40 (40% ethylene glycol, 30% Ficoll and 0.3 M sucrose in phosphate buffer saline containing 10% FBS). After mouse zygotes were exposed to EFS40 at $25^{\circ}C$ for 30 sec., they were immediately plunged into $LN_2$ or cultured for cryoprotectant toxicity test without freezing. The results obtained in these experiments were summarized as follows: After thawing, survival rates to the 2-cell stage of zygotes exposed to or vitrified in EFS 40 (98.5%, 95.2%) were not significantly difference compared with that of control (100%). However, the developmental rates upto blastocyst and hatching blastocyst in vitrified groups (66.7, 50.0%) were lower than those of control (93.9, 81.8%) or exposed group (94.0, 78.8%) (p<0.05). When the influence of vitrification and exposure to cryoprotectant on the in vitro development of mouse zygotes was assessed by the SCE frequency, the SCE frequency in exposed ($20.2{\pm}2.1$) to or vitrified embryos ($21.4{\pm}3.2$) was higher than that in control embryos ($16.8{\pm}1.5$). These results suggest that the frequency of SCE was increased after cryoprotectant exposure or Vitrification although developmental rates of zygotes upto blastocysts and /or hatching blastocysts were not afected by cryoprotectant.

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Effects of Chitosan on Quality and Shelf-life of Paeksulgis Added Chitosan (키토산 첨가에 따른 백설기의 품질특성 및 저장성)

  • 정현숙;박찬성;노홍균
    • Food Science and Preservation
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    • v.8 no.4
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    • pp.427-433
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    • 2001
  • The purpose of this study was to investigate the effect of chitosan on the shelf-life and quality of Paeksulkis(Korea rice cake). Paeksulgis containing 0-0.5% chitosan were stored at 5$^{\circ}C$ for 4 week and 2$0^{\circ}C$ for 1 week to test the effect of extenting shelf-life of Paeksulgis by chitosan. The pH of Paeksulkis was 5.65 without chitosan and pH of those were about 7.0(6.94-7.01) with 0.05-0.5% level of chitosan. Moisture content of Paekrukis wish or without chitosan was 38-40%. In Hunter’s color values of Paeksulkis of control, the lightness (L) was 84.28, redness(a) was -1.56 and yellowness(b) was 7.68. The lightness (L), redness(a) and yellowness(b) of Paeksulkis were increased by the increasing concentration of chitosan. In mechanical characteristics, cohesiveness concentration of Paeksulkis were the highest in control while obtained the highest score in color, after swallowing and overall quality (p<0.05). The score of flavor and consistency of Paeksulkis with different levels of chitosan wre not significant while the score of moisture in Paeksulkis with 0.05-0.5% level of chitosan was significantly higher than control (p<0.05). The score of flavor and consistency of Paeksulkis with different levels of chitosan were not significant while the score of moisture in Paeksulkis with 0.05-0.5% level of chitosan was significantly higher than control (p<0.05). Total bacterial counts (TBC) of Paeksulgis immediately before storage were 4.2$\times$10$^2$CFU/g in control and those containing 0.3-0.5% of chitosan were 0.5-1.0 log cycle lower than control. TBC of Paelsulgis containing chitosan was lower than increased for 2 weeks, reached at 1.8$\times$10$^{5}$ CFU/g and decreased for 2 weeks, reached at 1.8$\times$10$^4$CFU/g during storage at 5$^{\circ}C$. TBC of Paeksulkis with more than 0.3% of chitosan were 1.9 log cycles lower than that of control during storage at 5$^{\circ}C$. TBC of Paeksulkis with more than 0.3% of chitosan were 1.9 log cycles lower than that of control during storage at 5$^{\circ}C$ for 4 weeks. TBC of Paeksulgis increased to 10$^{8}$ CFU/g in control and 10$^{6}$-10$^{7}$ CFU/g in more than 0.3% chitosan during storage at 20$^{\circ}C$ for 1 week. The shelf-life of Paeksulkis was increased with increasing concentration of chitosan both temperature at 5$^{\circ}C$ and 20$^{\circ}C$.

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