• Preventive Nutrition and Food Science
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• v.5 no.4
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• pp.230-233
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• 2000

The present work was designed to determine whether change in fluidity of the mitochondrial membrane affects mitochondrial {TEX}$F_{1}${/TEX}{TEX}$F_{0}${/TEX}ATPase characteristics in NIDDM-prone BHE/Cdb rat. Isolated mitochondria fom BHE/Cdb rat fed a 6% coconut oil or corn oil were functionally tested by an analysis of its respiration and the coupling of this process to ATP synthesis in presence of oligomycin, a specific inhibitor of oxidative phosphorylation (OXPHOS), that binds to the {TEX}$F_{1}${/TEX}{TEX}$F_{0}${/TEX}ATPase. Mitochondria from rats fed coconut oil were more responsive to the inhibitory action of oligomycin with respect to state 3 respiration, respiratory control (RC) ratio and ADP:P (P/O) ratio than were mitochondria from rats fed corn oil. In state 3 respiration, mitochondria from rats fed coconut oil consumed less oxygen than did mitochondria from rats fed corn oil. RC ratio was lower in the mitochondria from rats fed coconut oil than was mitochondria from rats fed corn oil. In P/O ratio, the mitochondria from rats fed coconut oil had a lower P/O ratio than did mitochondria from rats fed corn oil. The data showed that the chang influidity of the mitochondrial membrane by dietary fat affected mitochondrial {TEX}$F_{1}${/TEX}{TEX}$F_{0}${/TEX}ATPase characteristics. The present study on diet differences in {TEX}$F_{1}${/TEX}{TEX}$F_{0}${/TEX}ATPase characteristics provides considerable insight into the role diets play in the control of mitochondrial function, expecially OXPHOS in NIDDM with mitochondrial defects.

• The Korean Journal of Mycology
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• v.22 no.2
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• pp.122-129
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• 1994

The role of metal ions for the activity of the mitochondrial $F_1-ATPase$ was studied. Removal of non-heme iron ion from the mitochondria by dialysis against chelating agents, 10 mM ethylenediaminetetraacetic acid(EDTA) and 10 mM o-phenanthroline(o-Phe), led to 56% and 49% inactivation of the enzyme, respectively. The enzyme dialyzed against EDTA was reactivated 81% by the addition of 0.5 mM $Fe^{3+}$ and 70% by 0.5 mM $Mg^{2+}$. But, $Fe^{2+}$ did not reactivate the enzyme. Coexistence of 0.5 mM $Fe^{2+}$ and 0.5 mM $Mg^{2+}$ resulted in 95% reactivation of the enzyme, while $Fe^{3+}$ with 0.5 mM $Mg^{2+}$ did not reactivate the enzyme like the effect of $Fe^{2+}$ alone. The enzyme dialyzed against o-Phe showed the similar results. These data showed that $Fe^{3+}$ is predominantly required for the activity of the mitochondrial $F_1-ATPase$ in Lentinus edodes and stimulated the activity of it by $Mg^{2+}$. $Fe^{3+}$ and $Mg^{2+}$ increased enzyme's affinity for substrate, decreasing the Km value 1.67 mM to 0.65 mM.

• Journal of Nutrition and Health
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• v.30 no.4
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• pp.379-385
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• 1997

This study was designed to determine whether genetic defects in the efficiency of ATP synthesis existed in the NIDDM-prone BHE/cdb rat and to determine whether these defects caused the development of glucose intolerance. Thyroxine treatment provided an excellent clue as to the nature of the genetic defects in this rat. The characteristics of hyperhyroid and control Sprague-Dawley(SD) and BHE/cdb rats were studied. Hyperthyroidism was induced through the addition of thyroxine($T_4$) to the diet(2mg/kg of diet). Active proton conductances and passive proton conductances were tested. Mitochondria from hyperhyroid BHE/cdb rats were less efficient iii active proton conductances than mitochondria from hyperhyroid SD rats. It showed that decreased efficiency of ATP synthesis in the BHE/cdb rat was probably related to defects in active proton conductance, Indicating aberrant FoATPase. The levels of $F_1F_0$ATPaseATPase activity were tested. Mitochondria from hyperthyroid BHE/cdb rats were less active than mitochondria from hyperthyroid SD rats. This may be an attribute of aberrant F$_1$ATPase and may contribute to the BHE/cdb strain s characteristic of reduced ATP synthesis efficiency. Glucose tolerances were tested. BHE/cdb rats were profoundly affected by thyroxine, whereas SD rats were less so. It showed that the diabetes phenotype in BHE/cdb rats was related to defects in thyroxine-induced uncoupling. These results showed the decreased efficiency of ATP synthesis due to genetic defects in $F_1F_0$ATPase had relevance to the characteristic of impaired glucose tolerance in the NIDDM-prone BHE/cdb rat.

• Journal of Microbiology and Biotechnology
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• v.10 no.4
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• pp.441-448
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• 2000

The production and cation flux-mediated activation of the P-type ATPase in Helicobacter pylori was investigated. Using the polymerase chain reaction (PCR), the proton pump genotype of H. pylori was found to be positive for both F-type and P-type ATPases. Yet, their production in terms of enzyme specific activity varied substantially depending on H. pylori strains, ranging over 3-fold. Its main constituent appeared to be the P-type ATPase pool, in contrast to other common bacterial compositions. Interestingly, the F-type ATPase was observed only when intact H. pyloricells were exposed to pH 4.5 or above (37$^{\circ}C$ for 1 h). In contrast, significant amounts of the P-type ATPase still remained after 1 h of cell treatment even at pH below 4.5. By enriching the acidic medium with RPMI(pH 3.0), the P-type ATPase was stabilized, accompained by inactivation of the F-type ATPase. Using H. pylori membrane vesicles, it was found that ammionia-mediated cation flux increased the rate of ATP hydrolysis by the P-type ATPase. Accordingly, these data strongly suggest that the P-type ATPase is involved or functions as an effective regulator for the cation flux across the H. pylori membrane, thereby reducing the risk of excess proton influx.

• The Korean Journal of Mycology
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• v.21 no.3
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• pp.157-164
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• 1993

The effects of the iron ions on the light-induced mitochondrial $F_1-ATPase$ in Lentinus edodes was studied. This enzyme activity was stimulated by each of the ferric, ferrous and magnesium ion. Especially, the activity of the enzyme by 5.0 mM ferric ion increased up to 107% in comparision with control group(100%). In the presence of magnesium ion, each of ferric and ferrous ion increased the activity of the enzyme, particulary, coexistence of 0.1 mM magnesium and 5.0 mM ferric ion increased the activity up to 270% with magnesium ion dependence. The activity of the enzyme was stimulated up to 268% by 5.0 mM ferric ion in the presence of 0.1 mM magnesium and 0.1 mM ferrous ion. Therefore, the coexistence of ferrous ion did not affect the activity. From the above, we propose that light-induced mitochondrial $F_1-ATPase$ in Lentinus edodes is a $Mg^{2+}{\cdot}Fe^{3+}{\;}F_1-ATPase.$ The optimal pH and temperature for the enzyme were 7.5 and $66^{\circ}C$ respectively.

• The Korean Journal of Mycology
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• v.21 no.3
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• pp.165-171
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• 1993

The effects of the iron ions for the light-induced mitochondrial $F_0F_1-ATPase$ of Lentinus edodes was studied. The enzyme activity was stimulated up to 202% by 0.1 mM $Fe^{2-}$ ion, but was inhibited by $Fe^{3+}\;and\;Mg^{2+}$. In the presence of 0.5 mM $Mg^{2+}$, the activity also increased 32% by 0.1 mM $Fe^{2+}$ ion, and decreased to a similar extent by $Fe^{3+}$ ion than by only $Fe^{3+}$ ion. Also, the activity was inhibited 53% by 5.0 mM $Fe^{2-}$ ion in the presence of 0.5 mM $Mg^{2+}$ ion and various concentration of $Fe^{3+}$ ion(mM). These results showed that $Fe^{2+}$ strongly stimulated the enzyme activity and its role for the enzyme was independent of $Mg^{2+}$ ion, but was dependent of $Fe^{3+}$ ion. From inactivation of the enzyme by addition of metal chelating agent, EDTA, it is suggested that the enzyme is to be metalloenzyme. The optimal pH and temperature of the enzyme in the presence of 0.1 mM $Fe^{2+}$ was 7.6 and $63^{\circ}C$, respectively.

• Bulletin of the Korean Chemical Society
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• v.17 no.2
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• pp.104-105
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• 1996

• Journal of the Korean Chemical Society
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• v.40 no.10
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• pp.674-677
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• 1996

• Proceedings of the KSCN Conference
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• 1997.10a
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• pp.52-52
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• 1997

no Abstract, See Full Text

• Journal of Dairy Science and Biotechnology
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• v.33 no.1
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• pp.83-91
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• 2015

Yogurt is a product of the acidic fermentation of milk, which affects the survival of lactic acid bacteria (LAB). The aim of this present study was to examine the survival and acid stress response of Lactobacillus rhamnosus GG to low pH environment. The survival of LAB in commercial yogurt was measured during long-term storage. The enumeration of viable cells of LAB was determined at 15-day intervals over 52-weeks at $5^{\circ}C$. L. acidophilus, L. casei, and Bifidobacterium spp. showed low viability. However, L. rhamnosus GG exhibited excellent survival throughout the refrigerated storage period. At the end of 52-weeks, L. rhamnosus GG survived 7.0 log10 CFU/mL. $F_0F_1$ ATPase activity in L. rhamnosus GG at pH 4.5 was also evaluated. The ATPase activities of the membranes were higher when exposed at pH 4.5 for 24 h. The survival of L. rhamnosus GG was attributable to the induction in $F_0F_1$ ATPase activity. In addition, the mRNA expression levels of acid stress-inducible genes at low pH were investigated by qRT-PCR. clpC and clpE genes were up-regulated after 1 h, and atpA and dnaK genes were up-regulated after 24 h of incubation at pH 4.5. These genes could enhance the survival of L. rhamnosus GG in the acidic condition. Thus, the modulation of the enzymes or genes to assist the viability of LAB in the low pH environment is thought to be important.