• Journal of Microbiology and Biotechnology
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• v.20 no.12
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• pp.1614-1623
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• 2010

Bacteria were isolated from roots of sugarcane varieties grown in the fields of Punjab. They were identified by using API20E/NE bacterial identification kits and from sequences of 16S rRNA and amplicons of the cpn60 gene. The majority of bacteria were found to belong to the genera of Enterobacter, Pseudomonas, and Klebsiella, but members of genera Azospirillum, Rhizobium, Rahnella, Delftia, Caulobacter, Pannonibacter, Xanthomonas, and Stenotrophomonas were also found. The community, however, was dominated by members of the Pseudomonadaceae and Enterobacteriaceae, as representatives of these genera were found in samples from every variety and location examined. All isolates were tested for the presence of five enzymes and seven factors known to be associated with plant growth promotion. Ten isolates showed lipase activity and eight were positive for protease activity. Cellulase, chitinase, and pectinase were not detected in any strain. Nine strains showed nitrogen fixing ability (acetylene reduction assay) and 26 were capable of solubilizing phosphate. In the presence of 100 mg/l tryptophan, all strains except one produced indole acetic acid in the growth medium. All isolates were positive for ACC deaminase activity. Six strains produced homoserine lactones and three produced HCN and hexamate type siderophores. One isolate was capable of inhibiting the growth of 24 pathogenic fungal strains of Colletotrichum, Fusarium, Pythium, and Rhizoctonia spp. In tests of their abilities to grow under a range of temperature, pH, and NaCl concentrations, all isolates grew well on plates with 3% NaCl and most of them grew well at 4 to $41^{\circ}C$ and at pH 11.

• Journal of Microbiology and Biotechnology
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• v.24 no.11
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• pp.1574-1582
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• 2014

Bacteria recognize changes in their population density by sensing the concentration of signal molecules, N-acyl-homoserine lactones (AHLs). AHL-mediated quorum sensing (QS) plays a key role in biofilm formation, so the interference of QS, referred to as quorum quenching (QQ), has received a great deal of attention. A QQ strategy can be applied to membrane bioreactors (MBRs) for advanced wastewater treatment to control biofouling. To isolate QQ bacteria that can inhibit biofilm formation, we isolated diverse AHL-degrading bacteria from a laboratory-scale MBR and sludge from real wastewater treatment plants. A total of 225 AHL-degrading bacteria were isolated from the sludge sample by enrichment culture. Afipia sp., Acinetobacter sp. and Streptococcus sp. strains produced the intracellular QQ enzyme, whereas Pseudomonas sp., Micrococcus sp. and Staphylococcus sp. produced the extracellular QQ enzyme. In case of Microbacterium sp. and Rhodococcus sp., AHL-degrading activities were detected in the whole-cell assay and Rhodococcus sp. showed AHL-degrading activity in cell-free lysate as well. There has been no report for AHL-degrading capability in the case of Streptococcus sp. and Afipia sp. strains. Finally, inhibition of biofilm formation by isolated QQ bacteria or enzymes was observed on glass slides and 96-well microtiter plates using crystal violet staining. QQ strains or enzymes not only inhibited initial biofilm development but also reduced established biofilms.

• Archives of Pharmacal Research
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• v.28 no.2
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• pp.172-176
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• 2005

Phytochemical investigation of the whole plant of Amberboa ramosa led to the isolation of six sesquiterpene lactones which could be identified as $8{\alpha}$-hydroxy-$11{\beta}$-methyl-$1{\alpha}H,\;5{\alpha}H,\;6{\beta}H,\;7{\alpha}H,\;11{\alpha}H-guai-10(14)$, 4(15)-dien-6, 12-olide(2), $3{\beta},\;8{\alpha}-dihydroxy-11{\alpha}-methyl-1{\alpha}H,\;5{\alpha}H,\;6{\beta}H,\;7{\alpha}H,\;11{\beta}H-guai-10(14)$, 4(15)-dien-6, 12-olide (2), $3{\beta},\;4{\alpha},\;8{\alpha}-trihydroxy-4{\beta}(hydroxymethyl)-1{\alpha}H,\;5{\alpha}H,\;6{\beta}H,\;7{\alpha}H-guai-10(14)$, 11(13)-dien-6, 12-olide (3), $3{\beta},\;4{\alpha},\;8{\alpha}-trihydroxy-4{\beta}-(chloromethyl)-1{\alpha}H,\;5{\alpha}H,\;6{\beta}H,\;7{\alpha}H-guai-10(14)$, 11(13)-dien-6, 12-olide(4), $3{\beta},\;4{\alpha},\;dihydroxy-4{\beta}-(hydroxymethyl)-1{\alpha}H,\;5{\alpha}H,\;6{\beta}H,\;7{\alpha}H-guai-10(14)$, 11(13)-dien-6, 12-olide(5), $3{\beta},\;4{\alpha}-dihydroxy-4{\beta}-(chloromethyl)-8{\alpha}-(4-hydroxymethacrylate)-1{\alpha}H,\;5{\alpha}H,\;6{\beta}H,\;7{\alpha}H-guai-10(14)$, 11(13)-dien-6, 12-olide (6) by spectroscopic methods. All of them showed inhibitory potential against butyrylcholinesterase.

• Journal of the Korean Chemical Society
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• v.21 no.2
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• pp.108-120
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• 1977

The approximate rates and stoichiometries of the reaction of lithium borohydride, with fifty two selected organic compounds containing representative functional groups under the standard condition (tetrahydrofuran, $0^{\circ}$), were studied.Among the active hydrogen compounds,primary alcohols and compounds containing an acidic proton liberated hydrogen relatively fast, but secondary and tertiary alcohols very sluggishly. All the carbonyl compounds examined were reduced rapidly within one hour. Especially, among the ${\alpha}{\beta}$-unsaturated carbonyl compounds tested, the aldehydes consumed one hydride cleanly, however the cyclic ketones consumed more than one hydride even at $-20^{\circ}$. Carboxylic acids were reduced very slowly, showing about 60% reduction in 6 days at $25^{\circ}$, however acyl chlorides reduced immediately within 30 minutes. On the other hand, the reductions of cyclic anhydrides proceeded moderately to the hydroxy acid stage, however the further reductions were very slow. Aromatic and aliphatic esters, with exception of the relatively moderate reduction of acetate, were reduced very slowly, however lactones were reduced at a moderate rate. Epoxides reacted slowly, but amides and nitriles as well as the nitro compounds were all inert to this reagent. And cyclohexanone oxime and phenyl isocyanate were reduced very sluggishly. Last of all, all sulfur compounds studied were inert to this hydride.

• Journal of Plant Biology
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• v.17 no.2
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• pp.69-83
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• 1974

To elucidate the relationship between chemical structure and biological activity of alantolactone, and also to investigate the relationship between the growth of cells and the respiration of Chlorella pyrenoidosa affected by alantolactone, alantolactone and isoalantolactone were isolated from Inula helenium L., and di-, and tetrahydroalantolactones were prepared by the hydrogenation. At a concentration of 5$\times$10-5M alantolactone, the growth rate of Chlorella was greatly reduced. The viability of cells was also reduced over 50% within 2 hr at a concentration of 2.5$\times$10-4M alantolactone. However, oxygen uptake was increased by 20% over 3 hr. And 14CO2 production from glucose-1-14C, glucose-6-14C and 14C-acetate-U.L. was also increased by alantolactone. Biological activityof alantolactone was significantly reduced by cysteine, reduced glutathione or cystine but not by tryptophan or histidine. It was detected by spectrophotometrically and by TLC that alantolactone was also reacted with thiols except cystine. The solution of alantolactone reached with thiol gave the UV absorption spectrum of $\alpha$-saturated ${\gamma}$-lactone, and most of SH groups were disappeared by the addition reaction. From the reaction mixture of alantolactone and cysteine, a lactone adduct was isolated and purified. Isoalantolactone had shown similar activity as alantolactone, however, it was appeared that di-, and tetrahydroalantolactones were not only inactive biologically but also in vitro. It was concluded that there was no correlationship between increased respiration rate and mortality of Chlorella. During the respiration TCA cycle was activated, however it was uncertain that the activation of EMP or HMP was also appeared. Alantolactone and isoalantolactone were biologically active compounds but others were inactive. The reactivity of $\alpha$-methylene ${\gamma}$-lactone moiety toward SH group was principally responsible for its biological activity in sesquiterpene lactones.

• Journal of the Korean Chemical Society
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• v.17 no.4
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• pp.275-285
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• 1973

The addition of one mole of aluminum chloride to three moles of sodium borohydride in tetrahydrofuran gives a turbid solution with enormously more powerful reducing properties than those of sodium borohydride itself. The reducing properties of this reagent were tested with 49 organic compounds which have representative functional groups. Alcohols liberated hydrogen immediately but showed no sign of hydrogenolysis of alkoxy group. Aldehydes and ketones were reduced rapidly within one hr. Acyl derivatives were reduced moderately, however, carboxylic acids were reduced much more slowly. Esters, lactones and epoxides were reduced readily than sodium borohydride or borane. Tertiary amide was reduced slowly, however, primary amide consumed one hydride for hydrogen evolution but reduction was sluggish. Aromatic nitrile was reduced much more readily than aliphatic nitrile. Nitro compounds were inert to this reagent but azo and azoxy groups were slowly attacked. Oxime was reduced slowly but isocyanate was only partially reduced. Disulfide and sulfoxide were attacked slowly but sulfide and sulfone were inert. Olefin was hydroborated rapidly.

• Journal of Microbiology and Biotechnology
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• v.18 no.5
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• pp.828-836
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• 2008

The biocontrol rhizobacterium Pseudomonas sp. M18 can produce two kinds of antibiotics, namely pyoluteorin (Plt) and phenazine-1-carboxylic acid (PCA), and is antagonistic against a number of soilborne phytopathogens. In this study, a luxR-type quorum-sensing regulatory gene, vqsR, was identified and characterized immediately downstream of the Plt gene cluster in strain MI8. A vqsR-inactivated mutant led to a significant decrease in the production of Plt and its biosynthetic gene expression. However, this was restored when introducing the vqsR gene by cloning into the plasmid pME6032 in trans. The vqsR mutation did not exert any obvious influence on the production of PCA and its biosynthetic gene expression and the production of N-acylhomoserine lactones (C4 and C8-HSLs) and their biosynthetic gene rhlI expression. Accordingly, these results introduce VqsR as a regulator of Plt production in Pseudomonas spp., and suggest that the regulatory mechanism of vqsR in strain M18 is distinct from that in P. aeruginosa. In addition, it was demonstrated that vqsR mutation did not have any obvious impact on the expression of Plt-specific ABC transporters and other secondary metabolic global regulators, including GacA, RpoS, and RsmA.

• Bulletin of the Korean Chemical Society
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• v.4 no.1
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• pp.3-9
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• 1983

Lithium n-butylborohydride was prepared from borane-dimethylsulfide (BMS) and n-butyllithium, and the approximate rates and stoichiometrics of its reactions with selected organic compounds containing representative functional groups were studied in THF at room temperature. Phenol and benzenetiol liberated hydrogen quickly and quantitatively, and the reactions of primary alcohols, 2,6-di-ter-butylphenol and 1-hexanethiol liberated hydrogen quantitatively within 3 hrs, whereas the reactions of secondary and tertiary alcohols were very slow. Aldehydes and ketones were reduced rapidly and quantitatively to the corresponding alcohols. Cinnamaldehyde utilized 1 equiv. of hydride rapidly, suggesting the reduction to cinnamyl alcohol. Carboxylic acids evolved 1 equiv. of hydrogen rapidly and further reduction was not observed. Anhydrides utilized 2 equiv. of hydride rapidly but further hydride uptake was very slow, showing a half reduction. Acid chlorides were reduced to the alcohol stage very rapidly. All the esters examined were reduced to the corresponding alcohol rapidly. Lactones were also reduced rapidly. Expoxides took up 1 equiv. of hydride at a moderate rate to be reduced to the corresponding alcohols. Nitriles and primary amides were inert to this hydride system, whereas tertiary amide underwent slow reduction. Nitroethane and nitrobenzene were reduced slowly, however azobenzene and azoxybenzene were quite inert. Cyclohexanone oxime evolved 1 equiv. of hydrogen rapidly, but no further reduction was observed. Phenyl isocyanate and pyridine N-oxide were proceeded slowly, showing 1.74 and 1.53 hydride uptake, respectively in 24 hours. Diphenyl disulfide was reduced rapidly, whereas di-n-butyl disulfide, sulfone and sulfonic acids were inert or sluggish. n-Hexyl iodide and benzyl bromide reacted rapidly, but n-octyl bromide, n-octyl chloride, and benzyl chloride reacted very slowly.

• Bulletin of the Korean Chemical Society
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• v.15 no.2
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• pp.132-138
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• 1994

Bis(diethylamino)aluminum hydride was utilized in a systematic study of the approximate rates and stoichiometry of the reaction of excess reagent with 55 selected organic compounds containing representative functional groups under standardized conditions (THF, $0^{\circ}C$, reagent to compound=4 : 1) in order to define the characteristics of the reagent for selective reductions. The reducing action of BEAH was also compared with that of the parent aluminum hydride. The reducing action of the reagent is quite similar to that of aluminum hydride, but the reducing power is much weaker. Aldehydes and ketones were readily reduced in 1-3 h to the corresponding alcohols. However, unexpectedly, a ready involvement of the double bond in cinnamaldehyde was realized to afford hydrocinnamyl alcohol. The introduction of diethylamino group to the parent aluminum hydride appears not to be appreciably influential in stereoselectivity on the reduction of cyclic ketones. Both p-benzoquinone and anthraquinone utilized 2 equiv of hydride readily without evolution of hydrogen, proceeded cleanly to the 1,4-reduction products. Carboxylic acids and acid chlorides underwent reduction to alcohols slowly, whereas cyclic anhydrides utilized only 2 equiv of hydride slowly to the corresponding hydroxylacids. Especially, benzoic acid with a limiting amount of hydride was reduced to benzaldehyde in a yield of 80%. Esters and lactones were also readily reduced to alcohols. Epoxides examined all reacted slowly to give the ring-opened products. Primary and tertiary amides utilized 1 equiv of hydride fast and further hydride utilization was quite slow. The examination for possibility of achieving a partial reduction to aldehydes was also performed. Among them, benzamide and N,N-dimethylbenzamide gave ca, 90% yields of benzaldehyde. Both the nitriles examined were also slowly reduced to the amines. Unexpectedly, both aliphatic and aromatic nitro compounds proved to be relatively reactive to the reagent. On the other hand, azo- and azoxybenzenes were quite inert to BEAH. Cyclohexanone oxime liberated 1 equiv of hydrogen and utilized 1 equiv of hydride for reduction, corresponding to N-hydroxycyclohexylamine. Pyridine ring compounds were also slowly attacked. Disulfides were readily reduced with hydrogen evolution to the thiols, and dimethyl sulfoxide and diphenyl sulfone were also rapidly reduced to the sulfides.

• Bulletin of the Korean Chemical Society
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• v.10 no.4
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• pp.382-388
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• 1989

The approximate rates and stoichiometry of the reaction of excess potassium tri-sec-butylborohydride ($K_s-Bu_3BH$) with selected organic compounds containing representative functional groups were determined under the standard conditions (0$^{\circ}C$, THF) in order to define the characteristics of the reagent for selective reductions. Primary alcohols evolve hydrogen in 1 h, but secondary and tertiary alcohols and amines are inert to this reagent. On the other hand, phenols and thiols evolve hydrogen rapidly. Aldehydes and ketones are reduced rapidly and quantitatively to the corresponding alcohols. Reduction of norcamphor gives 99.3% endo- and 0.7% exo-isomer of norboneols. The reagent rapidly reduces cinnamaldehyde to the cinamyl alcohol stage and shows no further uptake of hydride. p-Benzoquinone takes up one hydride rapidly with 0.32 equiv hydrogen evolution and anthraquinone is cleanly reduced to the 9,10-dihydoxyanthracene stage. Carboxylic acids liberate hydrogen rapidly and quantitatively, however further reduction does not occur. Anhydrides utilize 2 equiv of hydride and acyl chlorides are reduced to the corresponding alcohols rapidly. Lactones are reduced to the diol stage rapidly, whereas esters are reduced moderately (3-6 h). Terminal epoxides are rapidly reduced to the more substituted alcohols, but internal epoxides are reduced slowly. Primary and tertiary amides are inert to this reagent and nitriles are reduced very slowly. 1-Nitropropane evolves hydrogen rapidly without reduction and nitrobenzene is reduced to the azoxybenzene stage, whereas azobenzene and azoxybenzene are inert. Cyclohexanone oxime evolves hydrogen without reduction. Phenyl isocyanate utilizes 1 equiv of hydride to proceed to formanilide stage. Pyridine and quinoline are reduced slowly, however pyridine N-oxide takes up 1.5 equiv of hydride in 1 hr. Disulfides are rapidly reduced to the thiol stage, whereas sulfide, sulfoxide, sulfonic acid and sulfone are practically inert to this reagent. Primary alkyl bromide and iodide are reduced rapidly, but primary alkyl chloride, cyclohexyl bromide and cyclohexyl tosylate are reduced slowly.