• Environmental Mutagens and Carcinogens
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• v.16 no.2
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• pp.83-87
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• 1996

This study was performed by the sister chromatid exchanges (SCEs) to investigate the effects of Aphidicolin (APC) or 2, 4-dinitrophenoi (DNP) on cross-adaptive response to ultraviolet radiation (UV) or ethyl methanesulfonate (EMS) in Chinese hamster ovary (CHO) cells. The pretreatment with 1 J/m$^2$ UV decreased the yield of SCEs induced by subsequent treatment with 8 mM EMS in CHO cells. And the treatment with 10 $\mu$g/ml APC or 50 $\mu$M DNP during incubation after pretreatment with 1 J/m$^2$ UV increased the yield of SCEs induced by 8 mM EMS. The pretreatment with 2 mM EMS decreased the yield of SCEs induced by subsequent treatment with 5 J/m$^2$ UV. The treatment with 10 $\mu$g/ml APC during incubation after 2 mM EMS increased the yield of SCEs induced by 5 J/m$^2$ UV. These results suggest that APC and DNP inhibit cross-adaptive response to pretreatment with UV and subsequent treatment with EMS, and also cross-adaptive response to pretreatment with EMS and subsequent treatment with UV is inhibited by APC in CHO cells.

• Journal of Microbiology and Biotechnology
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• v.14 no.5
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• pp.967-971
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• 2004

The kinetics of sulfite uptake were examined in a wild-type laboratory strain of Saccharomyces cerevisiae to determine if carrier-mediated sulfite uptake involved a proton symport, as previous studies on sulfite uptake have suggested both an active process and facilitated diffusion. Accumulation of intracellular sulfite was initially rapid and linear up to 50 sec. Uptake was saturable at final concentrations equal to or greater than 3 mM sulfite, and increased 2-fold in the presence of 2% glucose. Uptake was significantly reduced in cells pretreated with 100-500 $\mu$M carbonyl cyanide mchlorophenylhydrazone (CCCP) or 2,4-dinitrophenol (DNP), both of which dissipate proton gradients. Uptake was also significantly inhibited in the presence of 1 mM arsenate, an inhibitor of ATP synthesis. Extracellular alkalization was observed in cells incubated with 1-2 mM sulfite in a weak tartrate buffer at pH 3.5 and 4.5. These findings suggest that the bisulfite ion, $HSO_3^-$, an anionic form of sulfite, is taken up by a carrier-mediated proton symport. A met16 sull sul2 mutant, impaired in both sulfite formation and sulfate uptake, was found able to grow on a medium with sulfite as the sole Sulfur source, indicating that the sulfate transporters Sul1p and Sul2p are not required for sulfite uptake.

• Journal of Pharmaceutical Investigation
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• v.2 no.1
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• pp.18-30
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• 1972

Renal pathways for excretion of sulfadiazine has been studied by standard clearance technique in the rabbit. 1. Large part of sulfadiazine filtered in the glomeruli is reabsorbed in the tubules, as visualized from the fact that Csd (clearance of sulfadiazine) amounts only a fraction of simultaneously measured Ccr (GFR). 2. Csd changed linearly with the rate of urine flow, whether it is increased by the duir etics or decreased by clamping u reter. 3. Csd remained unchanged until the plasma level of the Csdremained unchanged drug reached 10.0 mg%, and the amount transported in the tubules increased linearly with the increase in the load, exhibiting No maximum capacity for transport. 4. Csd was increased by 2,4-dinitrophenol which is an uncoupling agent of oxidative phosphorylation and decreased by probenecid which is on uricosuric agent. 5. During sodium bicarbonate infusion net secretion of sulfadiazine by tubules observed. All the evidences obtained in the rabbit indicated that sulfadiazine was reabsorbed by active, energy-requiring, or passive, simple diffusion, process, and secreted simultaneously by a probenecid-sensitive, active procss.

• YAKHAK HOEJI
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• v.38 no.2
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• pp.114-122
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• 1994

A study on the absorption mechanism of cefixime(CF), an oral ${\alpha}-amino$ group deficient cephalosporin antibiotic, has been undertaken through the rat jejunum and nasal cavity using an in situ simultaneous perfusion technique developed in our laboratory. CF was well absorbed in the jejunum and nasal cavity of rats at pH 5.0, but not at pH 7.0. CF absorption was studied over four orders of magnitude in concentration to determine saturability. Disappearance of CF in the perfusate followed first-order kinetics at all tested concentrations. The apparent first-order absorption rate constant was found to be dependent on the concentration over the range of $0.1\;mM{\sim}3\;mM$ in the jejunum and nasal cavity of rats. Inhibitors were added to determine the competitive inhibition of CF absorption. The presence of L-tyrosine, L-phenylalanine, alanine-alanine, glycine-glycine and cefadroxil produced the significant inhibition of CF absorption in the nasal cavity and jejunum. However, there was no evidence of the inhibition in the presence of cefazolin. In addition, The CF absorption in the nasal cavity and jejunum was inhibited significantly by ouabain and 2,4-dinitrophenol(DNP). This study suggested that CF is absorbed across the rat nasal cavity and jejunum by carrier-mediated transport mechanism and energy consuming system.

• Carbon letters
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• v.7 no.3
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• pp.188-195
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• 2006

Phosphoric acid-activated carbon WP's and zinc chloride-activated carbons WZ's were developed from wild cherry stones. The textural properties of the activated carbons were determined from nitrogen adsorption data at 77 K and the chemistry of the carbon surface, i.e. the surface carbon-oxygen groups (type and amount) was determined from the base and acid neutralization capacities (Boehm method). The adsorption of phenol, p-nitrophenol, p-chlorophenol, dinitrophenol and dichlorophenol was followed at 298 K. The activated carbons obtained were characterized by high surface area and large pore volumes as well as by high surface concentration of C-O groups. The investigated carbons exhibited high adsorption capacities towards phenols with these capacities increased with the increase of molecular weight and the decrease of the solubility of phenol in water. However, no general relationship could be observed between the adsorption capacities of carbons and any of their textural parameters or their surface chemistry. This may be attributed to the many factors controlling phenol adsorption and the different types and mechanisms of adsorption involved.

• Journal of Photoscience
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• v.8 no.2
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• pp.61-66
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• 2001

Using maize green- and white-leaf tissue, we have examined the effect of various chemicals on cytoplasmic leakage with respect to the light requirement or chloroplast targeting for their activities. Oxyfluorfen, oxadiazon, diuron, and paraquat, which are known as representative herbicides acting on plant chloroplasts, caused the electrolyte leakage only in the green tissues, whereas 2, 4-dinitrophenol, rose bengal (singlet oxygen producing chemical) and methyl-jasmoante (senscence-stimulating chemical) play a role both in green- and white-tissue. Benzoyl(a) pyrene, generating superoxide radical upon light illumination, functions only in white tissues. Tralkoxydim, metsulfuron-methyl and norflurazon showed no effect in two tested plant samples. In terms of light requirement in electrolyte leakage activity, diuron, oxyfluorfen, oxadiazon, rose bengal, and benzoyl(a) pyrene absolutely require the light for their functions, but other chemicals did not. based on these results, we could classify into four different response types according to whether chemicals require light or chlroplasts for their action. This classification is likely to be applied to simply and rapidly identify the requirement of light and chlroplasts for the actions of chemicals, thereby it makes easy to characterize many new herbicides that their action mechanisms are unclear, and to elucidate the mode of action of them.

• Microbiology and Biotechnology Letters
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• v.18 no.3
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• pp.233-238
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• 1990

The mechanism of intracellular accumulation of cadmium in a cadmium-ion tolerant yeast, Hansenula ammala B-7, which is an extreme cadmium tolerant strain and has the ability to take up a large amount of cadmium was investigated. The amounts of cadmium taken up by the scalded yeast cells were 2 to 3 times more than the value of the living cells. The living Hansenula anomala B-7 cells adsorbed 74% of cadmium taken up onto the other layer of the cells and 26% of it accumulated inside the cells. But the scalded cells adsorbed 98.3% of cadmium taken up and accumulated 1.7% of it inside the cells. A cadmium uptake and its accumulation were accelerated up to 162.3% and 275.4% by Triton X-100 in the living cells, respectively. Whereas in the scalded cell cadmium uptake was not affected by Triton X-100. Furthermore the cadmium uptake and its accumulation were strongly inhibited by metabolic inhibitors like 2,4-dinitrophenol, sodium azide and potassium cyanide in the living cells, but in the scalded cells cadmium uptake was not affected by metabolic inhibitors. These results suggested that the intracellular accumulation of cadmium by the cadmium-tolerant Hansenula anomala B-7 cells was apparently dependent of biological activity, and also gave evidence of the existance of energy-dependent system.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.5
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• pp.1330-1336
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• 2005

This study was carried out to investigate the motor activity and glucose transport and metabolism of Gaewool-Whadam-Jian(GWJ) in rat gastro-intestinal tract. The motor activity of the rat gastro-intestinal tract has been investigated by means of measuring barium sulfate passage degrees. Atropine treatment significantly delayed barium sulfate transit, and GWJ pretreatment increased intestinal motor activity, but not significant. GWJ administration showed no toxicity to kidney and liver. Transport and metabolism of glucose were studied in everted sac of rat small intestine with incubation under several conditions. The transport and metabolism of glucose were greater at jejunum than ileum. So, everted jejunum of rat were used to study the effect of GWJ. When GWJ were treated, the concentration of glucose were higher than untreated group. This result was thought to be influenced by the glucose in GWJ. When 2, 4 dinitrophenol and phlorizin were treated, the transport and metabolism of glucose were decreased, but GWJ treated together, the concentration of glucose in serosal solution increased. Gastric juice secretion and total acidity significantly decreased by administration of GWJ through duodenum region. The mechanism of effect of GWJ was still unidentified, Dut through continuous investigation, the effect of GWJ should be investigated.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.3
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• pp.305-313
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• 1999

To explore whether $Cl^-$ channel blockers interact with the ATP-sensitive $K^+\;(K_{ATP})$ channel, I have examined the effect of two common $Cl^-$ channel blockers on the $K_{ATP}$ channel activity in isolated rat ventricular myocytes using patch clamp techniques. In inside-out patches, 4,4'-diisothio-cyanatostilbene- 2,2'-disulfonic acid (DIDS) and niflumic acid applied to bath solution inhibited the $K_{ATP}$ channel activity in a concentration-dependent manner with $IC_{50}$ of 0.24 and 927 ${\mu}M,$ respectively. The inhibitory action of DIDS was irreversible whereas that of niflumic acid was reversible. Furthermore, DIDS-induced block was not recovered despite exposure to ATP (1 mM). In cell-attached and inside-out patches, DIDS blocked the pinacidil- or 2,4-dinitrophenol (DNP)-induced $K_{ATP}$ channel openings. In contrast, niflumic acid did not block the pinacidil-induced $K_{ATP}$ channel openings in inside-out patches, but inhibited it in cell-attached patches. DIDS and niflumic acid produced additional block in the presence of ATP and did not affect current-voltage relationship and channel kinetics. All these results indicate that DIDS among $Cl^-$ channel blockers specifically blocks the cardiac $K_{ATP}$ channel.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.6
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• pp.741-748
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• 1997

In the present study, we have investigated the effect of metabolic inhibition on the inward rectifier K current ($I_{K1}$). Using whole cell patch clamp technique we applied voltage ramp from +80 mV to -140 mV at a holding potential of -30 mV and recorded the whole cell current in single ventricular myocytes isolated from the rabbit heart. The current-voltage relationship showed N-shape (a large inward current and little outward current with a negative slope) which is a characteristic of $I_{K1}$. Application of 0.2 mM dinitrophenol (DNP, an uncoupler of oxidative phosphorylation as a tool for chemical hypoxia) to the bathing solution with the pipette solution containing 5 mM ATP, produced a gradual increase of outward current followed by a gradual decrease of inward current with little change in the reversal potential (-80 mV). The increase of outward current was reversed by glibenclamide ($10\;{\mu}M$), suggesting that it is caused by the activation of $K_{ATP}$. When DNP and glibenclamide were applied at the same time or glibenclamide was pretreated, DNP produced same degree of reduction in the magnitude of the inward current. These results show that metabolic inhibition induces not only the increase of $K_{ATP}$ channel but also the decrease of $I_{K1}$. Perfusing the cell with ATP-free pipette solution induced the changes very similar to those observed using DNP. Long exposure of DNP (30 min) or ATP-free pipette solution produced a marked decrease of both inward and outward current with a significant change in the reversal potential. Above results suggest that the decrease of $I_{K1}$ may contribute to the depolarisation of membrane potential during metabolic inhibition.