• 한국동물학회:학술대회논문집
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• 한국동물학회 1999년도 한국생물과학협회 학술발표대회
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• pp.11-11
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• 1999

;It has been reported that suspension-cultured rice cells grown on mixed carbon sources of glucose (GIc) and acetate exhibited diauxic growth in which acetate was the preferred carbon source (Lee and Lee, 1996). Carrot (Daucus carota L.) suspension cells, showing a diauxic growth very similar to that of rice cells, were used to delineate the mechanisms underlying this preferential use of acetate over GIc. Uptakes of both GIc and 3-0-methylglucose (3-0MG), a non-metabolizable GIc analogue, were similarly inhibited when acetate or butylate, weak acids which are capable of transporting protons into the cytosol, were present in the uptake assay mixture containing cells harvested during the GIc-utilizing second growth phase. Inhibition of GIc uptake by these weak acids was similar when equivalent experiments were carried out with isolated plasma membranes. It was further shown that Glc uptake, which requires a proper proton gradient across the plasma membranes, was inhibited during the first growth phase by acetate-mediated alkalization of growth medium and/or simultaneous acidification of cytosol. This study strongly suggests that Glc utilization in plant cells is inhibited by co-presenting carbon source(s) which can alter the proton gradient across the plasma membrane. We further examined diauxic growth in culture containing GIc and malate. Unlike the case in the culture with GIc and acetate, carrot cells used GIc first. Malate was utilized only after Glc is depleted from medium. These results indicate that GIc can be a preferred or less-preferred carbon source depending on the competing carbon source. It was noted that malate was not directly taken up by cells. Instead it was converted extracellularly into fumarate which was subsequently transported into cells. During the malate-growth phase malate uptake was negligible, and fumarate uptake was active and pH-sensitive. It was shown that fumarase released into medium was responsible for the extracellular conversion of malate into fumarate. An immunoblot experiments showed that fumarase antibody raised against Arabidopsis fumarase provided positive signals only in medium in malate culture, not in fumarate or GIc cultures. This study demonstrates the first example in that fumarase, a mitochondria marker enzyme, can be present in places other than mitochondria.ndria.

• 폴리머
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• 제25권1호
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• pp.108-114
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• 2001

Krebs회로 산인 L-malic acid와 glycerol의 -OH와 -COOH의 몰비를 달리하면서 가교공중합체 poly(glycerol-co-malate)s를 합성하였다. 단량체 및 합성된 가교공중합체를 적외선흡수 분광기법에 의하여 확인하였으며, pH에 따른 수팽윤도를 측정하였다. 용액의 pH가 증가함에 따라 그 공중합체 수화겔의 수팽윤도는 증가하였으며, 각 pH에서 가교공중합체는 -COOH에 대한 -OH기의 몰비가 증가할수록 수팽윤도가 감소하였다. 용액의 pH 변화에 따른 가교공중합체의 가수분해도를 37${\circ}C$에서 조사한 결과 용액의 pH가 증가함에 따라 가수분해는 빨리 진행되었다. 모델 약물로는 diclofenac monosodium salt를 사용하여 pH에 따른 약물방출 거동을 조사한 결과 약물의 방출은 pH가 증가할수록 더 빨리 방출되었고, 합성된 가교공중합 에스테르는 미반응 카르복실기와 하이드록실기로 인해 pH에 의해 크게 영향을 받음을 확인하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제22권1호
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• pp.82-89
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• 2009

Two in vitro experiments were conducted to examine the effects of propionate precursors in the dicarboxylic acid pathway on ruminal fermentatation characteristics, $CH_4$ production and degradation of feed by rumen microbes. Fumarate or malate as sodium salts (Exp. 1) or acid type (Exp. 2) were added to the culture solution (150 ml, 50% strained rumen fluid and 50% artificial saliva) to achieve final concentrations of 0, 8, 16 and 24 mM, and incubated anaerobically for 0, 1, 3, 6, 9 and 12 h at $39^{\circ}C$. For both experiments, two grams of feed consisting of 70% concentrate and 30% ground alfalfa (DM basis) were prepared in a nylon bag, and were placed in a bottle containing the culture solution. Addition of fumarate or malate in both sodium salt and acid form increased (p<0.0001) pH of culture solution at 3, 6, 9 and 12 h incubations. The pH (p<0.0001) and total volatile fatty acids (VFA, p<0.05) were enhanced by these precursors as sodium salt at 3, 6 and 9 h incubations, and pH (p<0.001) and total VFA (p<0.01) from fumarate or malate in acid form were enhanced at a late stage of fermentation (9 h and 12 h) as the addition level increased. pH was higher (p<0.001) for fumarate than for malate as sodium salt at 3 h and 6 h incubations. Propionate ($C_3$) proportion was increased (p<0.0001) but those of $C_2$ (p<0.05) and $C_4$ (p<0.01 - p<0.001) were reduced by the addition of sodium salt precursors from 3 h to 12 incubation times while both precursors in acid form enhanced (p<0.011 - p<0.0001) proportion of $C_3$ from 6h but reduced (p<0.018 - p<0.0005) $C_4$ proportion at incubation times of 1, 3, 9 and 12 h. Proportion of $C_3$ was increased (p<0.05 - p<0.0001) at all incubation times by both precursors as sodium salt while that of $C_3$ was increased (p<0.001) from 6h but $C_4$ proportion was decreased by both precursors in acid form as the addition level increased. Proportion of $C_3$ was higher (p<0.01 - p<0.001) for fumarate than malate as sodium salt from 6 h incubation but was higher for malate than fumarate in acid form at 9 h (p<0.05) and 12 h (p<0.01) incubation times. Increased levels (16 and 24 mM) of fumarate or malate as sodium salt (p<0.017) and both precursors in acid form (p<0.028) increased the total gas production, but no differences were found between precursors in both chemical types. Propionate precursors in both chemical types clearly reduced (p<0.0001 - p<0.0002) $CH_4$ production, and the reduction (p<0.001 - p<0.0001) was dose dependent as the addition level of precursors increased. The $CH_4$ generated was smaller (p<0.01 - p<0.0001) for fumarate than for malate in both chemical types. Addition of fumarate or malate as sodium type reduced (p<0.004) dry matter degradation while both precursors in both chemical types slightly increased neutral detergent fiber degradability of feed in the nylon bag.

• Asian-Australasian Journal of Animal Sciences
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• 제22권6호
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• pp.819-826
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• 2009

An in vitro study was conducted to investigate the effect of malate or fumarate on fermentation characteristics, and production of conjugated linoleic acid (CLA) and methane ($CH_4$) by rumen microbes when incubated with linolenic acid (${\alpha}-C_{18:3}$). Sixty milligrams of ${\alpha}-C_{18:3}$ alone (LNA), or ${\alpha}-C_{18:3}$ with 24 mM malic acid (M-LNA) or ${\alpha}-C_{18:3}$ with 24 mM fumaric acid (F-LNA) were added to the 150 ml culture solution consisting of 75 ml strained rumen fluid and 75ml McDougall's artificial saliva. Culture solution for incubation was also made without malate, fumarate and ${\alpha}-C_{18:3}$ (Control). Two grams of feed consisting of 70% concentrate and 30% ground alfalfa (DM basis) were also added to the culture solution of each treatment. In vitro incubation was made anaerobically in a shaking incubator up to 12 h at $39^{\circ}C$. Supplementation of malate (M-LNA) or fumarate (F-LNA) increased pH at 6 h (p<0.01) and 12 h (p<0.001) incubation times compared to control and linolenic acid (LNA) treatments. Both malate and fumarate did not influence the ammonia-N concentration. Concentration of total VFA in culture solution was higher for M-LNA and F-LNA supplementation than for control and LNA treatments from 6 h (p<0.040) to 12 h (p<0.027) incubation times, but was not different between malate and fumarate for all incubation times. Molar proportion of $C_3$ was increased by F-LNA and M-LNA supplementation from 6 h (p<0.0001) to 12 h (p<0.004) incubation times compared to control and LNA treatments. No differences in $C_{3}$ proportion, however, were observed between M-LNA and F-LNA treatments. Accumulated total gas production for 12h incubation was increased (p<0.0002) by M-LNA or F-LNA compared to control or LNA treatment. Accumulated $CH_4$ production for 12 h incubation, however, was greatly reduced (p<0.0002) by supplementing malate or fumarate compared to the control, and its production from M-LNA or F-LNA treatment was smaller than that from LNA treatment. Methane production from LNA, M-LNA or F-LNA treatment was steadily lower (p<0.01 - p<0.001) from 3 h incubation time than that from the control, and was also lower for M-LNA or F-LNA treatment at incubation times of 6 h (p<0.01) and 9 h (p<0.001) than for LNA treatment. Methane production from LNA, however, was reduced (p<0.01 - p<0.001) from 3 h to 9 h incubation times compared to the control. Both malate and fumarate increased concentration of trans11-$C_{18:1}$ from 3 h to 12 h incubation (p<0.01), cis9,trans11-CLA up to 6 h incubation (p<0.01 - p<0.01), trans10,cis12-CLA at 3 h (p<0.05) and 12 h (p<0.01), and total CLA for all incubation times (p<0.05) compared to corresponding values for the ${\alpha}-C_{18:3}$ supplemented treatment (LNA). In conclusion, malate and fumarate rechanneled the metabolic $H_2 pathway to production of propionate and CLA, and depressed the process of biohydrogenation and methane generation. Linolenic acid alone would also be one of the optimistic alternatives to suppress the $CH_4$ generation.

• Bulletin of the Korean Chemical Society
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• 제32권11호
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• pp.4067-4070
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• 2011

• International Journal of Industrial Entomology and Biomaterials
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• 제2권2호
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• pp.149-153
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• 2001

The influence of baculovirus Bombyx mori Nuclear Polyhedrosis virus (BmNPV) infection on intermediary metabolic pathways in silkworm Bombyx mori L. was investigated. Studies revealed that NADP-linked malate dehydrogenase activity in hemolymph of infected silkworms at 96 hrs post infection (p.i.) with visible symptoms of infection was enhanced in comparison to healthy larvae of the same age. Also, NADP-dependent MDH activity was significantly lower in fat body cytosol of infected larvae at 96 hrs p.i. when compared to healthy larvae. Similarly, some biometabolic parameters like growth, protein content and cholesterol titer were observed to be influenced by baculovirus infection. While the growth of infected larvae was significantly retardedi protein content was also drastically reduced in both hemolymph and fat body tissues. Cholesterol titers however, was enhanced in infected larvae. The results observed herein point to a significant change in the normal biochemical and biometabolic pathways required for growth and development following BmNPV infection.

• 한국식품영양과학회지
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• 제37권12호
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• pp.1548-1553
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• 2008

한천 가수분해물의 각종 생리활성을 실험한 결과, $100^{\circ}C$ 이상의 조건에서 가수분해된 시료에서 B. cereus와 B. subtilis에 강한 항균활성을 나타내었는데 특히, malate 가수분해물에서 활성이 높은 것으로 나타났으며, 일부 획분에서는 E. coli에 대해서도 확실한 항균 효과를 나타내었고, 약하지 만 S. aureus에 대해서도 항균활성을 나타내었다. Citrate와 malate로 가수분해된 시료에서 $55{\sim}80%$의 tyrosinase 활성을 저해하는 것으로 나타났으나 전체적으로 활성이 낮았다. 한천 가수분해물의 비피더스균 증식 효과는 온도에 관계없 이 lactate, citrate 및 malate로 가수분해된 시료에서 B. infantis 균에 대해 증식효과가 확인되었다. 한천 가수분해물에서는 ACE 저해능이 확인되지 않았으며, 항혈액응고활성도 거의 나타나지 않았다. 한편, 세포증식 억제능은 0.5%의 citrate와 lactate로 $110^{\circ}C$에서 180분간 가수분해되어진 시료에서 강한 활성이 확인되었으며, 이들 시료를 정제하여 얻어진 특정 획분(C3과 L3)에서도 강한 세포 증식 억제능이 확인되었다.

• KSBB Journal
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• 제30권5호
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• pp.253-256
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• 2015

송이버섯 추출액의 박테리아에 대한 항균력을 측정하기 위하여 최소저해농도를 확인한 결과 젓갈 제조시 빈번하게 발생하는 부패균, 어병원인 균등 9가지 박테리아에 대해 성장이 저해되는 것을 확인하였다. 확인된 송이버섯 추출액의 항균력을 저염 젓갈의 제조 공정에 적용하기 위해 식품보존제인 사과산나트륨과 아질산나트륨을 함께 첨가하여 S. aureus에 대한 최소저해농도를 확인하였다. 그 결과 사과산나트륨과 아질산나트륨의 최소저해농도가 각각 0.25 g/L와 0.025 g/L로 크게 낮아지는 것을 확인할 수 있었다. 본 연구를 통해 항균력을 갖는 송이버섯 추출액을 첨가함으로써 일반적으로 첨가되는 식품보존제의 농도를 크게 낮출 수 있었을 뿐 아니라 송이버섯의 다양한 기능성이 추가된 고급화된 저염 젓갈을 개발할 수 있을 것으로 예상된다.

• Journal of Applied Biological Chemistry
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• 제42권1호
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• pp.1-6
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• 1999

Poly-${\beta}$-hydroxybutyrate (PHB) and enzymes related PHB metabolism have been measured in nitrogen-fixing symbiosis of chickpea and cowpea plants. Bacteroids from chickpea and cowpea contained PHB to 0.8% and 43% of their dry weight, respectively, whereas the free-living cells CC 1192 and I 16 produced $285{\pm}55mg$ and $157{\pm}18mg$ of PHB g (dry weight)$^{-1}$. To further understand why chickpea bacteroids contained little PHB, the enzyme activities of PHB metabolism (3-ketothiolase, acetoacetyl-CoA reductase, PHB depolymerase, and 3-hydroxybutyrate dehydrogenase), the TCA cycle (malate dehydrogenase, citrate synthase, and isocitrate dehydrogenase), and related reactions (malic enzyme, pyruvate dehydrogenase, and glutamate:2-oxoglutarate transaminase) were compared in extracts from chickpea and cowpea bacteroids and the respective free-living bacteria. Significant differences were observed between chickpea and cowpea bacteroids and between the bacteroid and free-living forms of CC 1192, with respect to the capacity for some of these reactions. It is indicated that a greater potential for oxidizing malate to oxaloacetate in chickpea bacteroids could be a factor that favors the utilization of acetyl-CoA in TCA cycle rather than for PHB synthesis.

• Journal of Ginseng Research
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• 제8권1호
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• pp.15-21
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• 1984

It has been known that ethyl acetate fraction and petroleum ether fraction prepared from ginseng are inhibitory to the L5178Y and sarcoma 180 cell at the concentrations o! 0.Imgfml or 0.2mg/ml. The shiny was carried out to examine effects of the two fractions on the activities of RNA polymerase, succinate dehydrogenase (SDH) and malate dehydrogenase (MDH) present in normal rabbit liver. The ethyl acetate fraction did not show any inhibitory effect on the RNA polymerase and SDH activity at the concentrations of 0.Imgfml and 0.2mglml, but inhibited malate dehydrogenase activity by 12.3% and 15.5%, at the same concentrations, respectively. The fraction also inhibited all the three enzymes at higher concentrations tested, but stimulated the succinate dehydrogenase activity at 0.024mg/ml to increase the enzyme activity by 14.6%. The petroleum ether fraction activated the SDH activity by 12.9% and 20.8%, at the concentration of 0.1mg/ml and 0.2mg/ml respectively. But the fraction did not affect the MDH activity at the same concentration. The fraction, however, inhibited the MDH activity and activated the SDH activity by 13.5% and 18.2%, at the concentration of 0.8mg/ml respectively.