• Journal of Microbiology and Biotechnology
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• v.18 no.5
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• pp.880-884
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• 2008

A strain of Streptomyces sp. (M10) antagonistic to Botrytis cinerea was isolated from orchard soil obtained from Jeju Island, Korea. An antifungal substance (CN1) was purified from the culture extracts of the strain, and then identified as valinomycin through extensive spectroscopic analyses. Valinomycin showed potent in vitro antifungal activity against Botrytis cinerea and also in vivo control efficacy against Botrytis blight development in cucumber plants. Overall, the disease control efficacy of valinomycin was similar to that of vinclozolin, a commercial fungicide. This study provides the first report on the disease control efficacy of valinomycin against Botrytis blight.

• Journal of the Korean Magnetic Resonance Society
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• v.12 no.1
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• pp.51-59
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• 2008

Convection effect in liquids has been one of the main targets to be overcome in pulsed-field-gradient NMR measurements of self-diffusion coefficients since the temperature gradient along the sample tube generated by the heating and/or cooling process causes the effect, resulting in additional diffusion. It is known that the capillary is the most appropriate tube type for diffusion experiments at variable temperatures since the narrower tube suppresses convection effectively. For evaluating the properties of hydrogen bonding, diffusion coefficients of the $K^+$-complexed and free valinomycin in a micro tube have been determined at various temperatures. From the analysis of the obtained diffusion coefficient values, we could conclude that the intramolecular hydrogen bonding in both of the $K^+$ complexed and free valinomycin in a non-polar solvent is preserved over the observed temperature range, and the temperature dependence of hydrogen bonding is more pronounced in free valinomycin. It is also thought that there is no big change in the radius of the $K^+$-complexed as temperature is varied, and the ratio of overall radius, $r_{complex}/r_{free}$ is slightly decreased as temperature rises.

• Natural Product Sciences
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• v.13 no.2
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• pp.144-147
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• 2007

Using antifungal activity-guided fractionation, an actinomycete, Streptomyces padanus strain TH-04, which was isolated from mummified peaches infected with Monilinia fructicola, was found to produce the valinomycin (1). The structure of 1 was established using spectroscopic data, which including one- and two-dimensional NMR experimental and mass spectroscopy. Valinomycin (1) showed antifungal activity against Phytophthora capsici, with an IC$_{50}$ value of 15.9 ${\mu}$g/mL.

• Applied Chemistry for Engineering
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• v.9 no.5
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• pp.734-741
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• 1998

Electrode characteristics were studied in the interface between sample solutions and $K^+$ ion selective PVC membrane electrodes containing neutral carriers, dibenzo-18-crown-6(D18Cr6) and valinomycin(Val). The effect of doping of base electrolytes, the chemical structure and the content of carrier, variation of plasticizer, membrane thickness, and concentration variation of sample solution on the response characteristics of electrode such as the measured Nernstian slope, the detection limit, the linear response range, and potentiometric selectivity coefficients, were studied. In order to synthesize the membrane D18Cr6 and Val as neutral carriers were used, and complex between the carrier and $K^+$ ions were used as active materials. PVC membrane electrodes were made of plasticizers (DBP, DOS, and DBS), the base electrolyte[potassium tetraphenylborate(KTPB)], and solvent(THF). The chemical structure of carrier D18Cr6 was best for electrode and ideal electrode characteristics were appeared especially in case of doping of TPB. The optimum carrier content was about 3.23 wt % in case of D18Cr6 and Val. DBP was best as a plasticizer. As membrane thickness decreased the electrode characteristics was improved. But its characteristics were lowered below the optimum membrane thickness because of the elution of carrier, deterioration of membrane strength, etc. In the case of D18Cr6, the selectivity coefficients by the mixed solution method for the $K^+$ ion were in the order of $NH_4{^+}>Ca^{2+}>Mg^{2+}>Na^+$.

• Food Science and Biotechnology
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• v.14 no.4
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• pp.554-557
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• 2005

As a device for taste sensation, an 8-channel taste evaluation system was prepared and applied for discriminant analysis of marketed liquor. The biomimetic polymer membranes for the system were prepared through a casting procedure by employing polyvinyl chloride, bis (2-ethylhexyl)sebacate as plasticizer and electroactive materials such as valinomycin in the ratio of 33:66:1, and were separately attached over the sensitive area of ion-selective electrodes to construct the corresponding taste sensor array. The sensor array in conjunction with a double junction reference electrode was connected to a high-input impedance amplifier and the amplified sensor signals were interfaced to a personal computer via an A/D converter. When the signal data from the sensor array for 3 groups of marketed liquor like Maesilju, Soju and beer were analyzed by principal component analysis after normalization, it was observed that the 1st, 2nd and 3rd principal component were responsible for most of the total data variance, and the analyzed liquor samples were discriminated well in 2 dimensional principal component planes composed of the 1st-2nd and the 1st-3rd principal component.

• Journal of Microbiology and Biotechnology
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• v.13 no.6
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• pp.833-840
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• 2003

Sperm motility of salmonid fishes is suppressed by external $K^{+}$ and initiated by decrease of $K^{+}$ concentration surrounding the sperm. It was shown that the decrease in external $K^{+}$ concentration induced not only the initiation of sperm motility, but also hyperpolarization of the plasma membrane and synthesis of cAMP in the sperm of rainbow trout, steelhead trout, and masu salmon. Inhibitors of $K^{+}$ channels, especially voltage-dependent $K^{+}$ channels, inhibited these three reactions, and the inhibitions were abolished by subsequent addition of a $K^{+}$ ionophore, valinomycin, suggesting that $K^{+}$ efflux through the $K^{+}$ channel contributes to rapid changes in the membrane potential of sperm and cAMP synthesis, thereby resulting in the initiation of sperm motility of salmonid fishes.

• The Plant Pathology Journal
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• v.40 no.3
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• pp.322-328
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• 2024

Soybean (Glycine max), a crucial global crop, experiences yearly yield reduction due to diseases such as anthracnose (Colletotrichum truncatum) and root rot (Fusarium spp.). The use of fungicides, which have traditionally been employed to control these phytopathogens, is now facing challenges due to the emergence of fungicide-resistant strains. Streptomyces bacillaris S8 strain S8 is previously known to produce valinomycin t through a nonribosomal peptide synthetase (NRPS) pathway. The objective of this study was to evaluate the antifungal activity of S. bacillaris S8 against C. truncatum and Fusarium sp., assessing its efficacy against soybean pathogens. The results indicate that strain S8 effectively controlled both above-ground and underground soybean diseases, using the NRPS and NRPS-related compound, suggesting its potential as a biological control in plant-microbe interactions. These findings underscore the pivotal role of the stain S8 in fostering healthy soybean microbial communities and emphasize the significance of microbiota structure studies in unveiling potent biocontrol agents.

• The Korean Journal of Physiology
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• v.30 no.1
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• pp.63-76
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• 1996

The aim of present study was to characterize phosphate uptake and to investigate the mechanism for the insulin and insulin-like growth factor(IGF) stimulation of phosphate uptake in primary cultured rabbit renal proximal tubule cells. Results were as follows : 1. The primary cultured proximal tubule cells had accumulated $6.68{\pm}0.70$ nmole phosphate/mg protein in the presence of 140 mM NaCl and $2.07{\pm}0.17$ nmole phosphate/mg protein in the presence of 140 mM KCl during a 60 minute uptake period. Raising the concentration of extracellular phosphate to 100 mM$(48.33{\pm}1.76\;pmole/mg\;protein/min)$ induced decrease in phosphate uptake compared with that in control cells maintained in 1 mM phosphate$(190.66{\pm}13.01\;pmole/mg\;protein/min)$. Optimal phosphate uptake was observed at pH 6.5 in the presence of 140 mM NaCl. Phosphate uptake at pH 7.2 and pH 7.9 decreased to $83.06{\pm}5.75%\;and\;74.61{\pm}3.29%$ of that of pH 6.5, respectively. 2. Phosphate uptake was inhibited by iodoacetic acid(IAA) or valinomycin treatment $(62.41{\pm}4.40%\;and\;12.80{\pm}1.64%\;of\;that\;of\;control,\;respectively)$. When IAA and valinomycin were added together, phosphate uptake was inhibited to $8.04{\pm}0.61%$ of that of control. Phosphate uptake by the primary proximal tubule cells was significantly reduced by ouabain treatment$(80.27{\pm}6.96%\;of\;that\;of\;control)$. Inhibition of protein and/or RNA synthesis by either cycloheximide or actinomycin D markedly attenuated phosphate uptake. 3. Extracellular CAMP and phorbol 12-myristate 13 acetate(PMA) decreased phosphate uptake in a dose-dependent manner in all experimental conditions. Treatment of cells with pertussis toxin or cholera toxin inhibited phosphate uptake. cAMP concentration between $10^{-6}\;M\;and\;10^{-4}\;M$ significantly inhibited phosphate uptake. Phosphate uptake was blocked to about 25% of that of control at 100 ng/ml PMA. 3-Isobutyl-1-methyl-xanthine(IBMX) inhibited phosphate uptake. However, in the presence of IBMX, the inhibitory effect of exogenous cAMP was not significantly potentiated. Forskolin decreased phosphate transport. Acetylsalicylic acid did not inhibit phosphate uptake. The 1,2-dioctanoyl-sn-glycorol(DAG) and 1-oleoyl-2-acetyl-sn- glycerol(OAG) showed a inhibitory effect. However, staurosporine had no effect on phosphate uptake. When PMA and staurosporine were treated together, inhibition of phosphate uptake was not observed. In conclusion, phosphate uptake is stimulated by high sodium and low phosphate and pH 6.5 in the culture medium. Membrane potential and intracellular energy levels are also an important factor fer phosphate transport. Insulin and IGF-I stimulate phosphate uptake through a mechanisms that involve do novo protein and/or RNA synthesis and decrease of intracellular cAMP level. Also protein kinase C(PKC) is may play a regulatory role in transducing the insulin and IGF-I signal for phosphate transport in primary cultured proximal tubule cells.

• Molecules and Cells
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• v.20 no.1
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• pp.127-135
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• 2005

The uptake of putrescine, spermidine and spermine by Fortner's hamster amelanocytic melanoma AMEL-3 cells was observed in this study to be time-dependent, temperature-sensitive, pH-dependent and saturable. Metabolic poisons nullified polyamine uptake, an indication that this is an energy-requiring mechanism. The presence of $Na^+$ ions was found to be requisite to full activity. Valinomycin, gramicidin, monensin and the calcium ionophore calcimycin were also observed to inhibit the process substantially. The transporter active site would seem to contain sulfhydryl groups. Other diamines and polyamine analogues, as well as cationic diamidines, suppressed putrescine uptake. The presence of the ornithine decarboxylase inhibitor DFMO in the culture medium induced putrescine inflows. Putrescine, in turn, induced the negative expression of the carrier, thus suggesting that this influx mechanism is governed by up/down regulation. The cationic diamidine CGP 40215A and its analogue CGP039937A competitively inhibited putrescine transport, with Ki values of 1.9 and $15{\mu}M$, respectively. The role of polyamine uptake in these cultures is discussed.

• Journal of Biosystems Engineering
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• v.27 no.3
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• pp.249-258
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• 2002

The fourteen different electrodes coated with polymeric lipid membrane were evaluated to selectively monitor the sweet, salty, sour and bitter tastes, and umami. The polymeric lipid membrane consisted of the three components, or polymer matrix, plasticizer and electroactive material, the compositional ratio of which was 1:1.25:1. Herein, the 14 different electroactive materials were used. Sucrose, NaCl, citric acid, caffeine and MSG were used as standard materials of sweet, salty, sour and bitter tastes, and umami. The linear responses of each electrode regarding 5 tastes were analyzed by means of the correlation coefficient between electric potential difference and concentration of a taste material when the linearity was based on a linear model and a thermodynamic model, respectively. As fur salty taste, the electrode coated with valinomycin had a selective linearity at the significance level of 0.01. For monitoring sweet taste, the electrode with oleylamine and the electrode with the mixture of tai-n-octylmethylammonium chloride and dioctylphosphate (2:8) showed the significant linearities at the levels of 0.05 and 0.10, respectively.