• Microbiology and Biotechnology Letters
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• v.40 no.4
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• pp.389-395
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• 2012

T-RFLP (terminal restriction fragment length polymorphism) analysis, one of the most highly adopted culture-independent microbial community analysis methods, was applied to evaluate the colonization of probiotics in experimental animal gut. Lactic acid bacteria that exhibited cinnamoyl esterase activity were isolated from Korean fermented vegetables and identified by 16S ribosomal RNA sequence analysis. Lactobacillus plantarum KK3, which demonstrated high chlorogenic acid hydrolysis by cinnamoyl esterase activity, and acid/bile salt resistances, was cultured, freeze-dried, and fed to mice and the microbiota in their feces were monitored by T-RFLP analysis. The T-RF of L. plantarum was detected in the feces of mice after the start of administration and lasted at least 31 days after the initial 7 day feeding. T-RFLP analysis was considered a useful tool to evaluate the gut colonization of probiotic L. plantarum. In order to prove that L. plantarum was from viable cells, we reisolated L. plantarum in the feces using cinnamoyl esterase activity media as the screening step. The colonization of L. plantarum KK3 in the mouse gut was confirmed by this research.

• Korean journal of applied entomology
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• v.40 no.3
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• pp.265-271
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• 2001

Resistance mechanisms in the green peach aphid (Myzus persicae) resistant to imidacloprid were investigated. Imidacloprid residues on the aphid integuments decreased slowly as time passed with no significant difference between the susceptible and resistant strains. Residue in the aphid body increased in both strains with time elapse, and was slightly more in the susceptible strain. A higher metabolic rate of imidacloprid in the resistant strain can be expected by the fact that more amount of imidacloprid were excreted in the resistant strain than in the susceptible one. The activity of AChE was higher 1.4 times in the resistant strain than in the susceptible one, and imidacloprid did not inhibit AChE at all in both strains. Piperonyl butoxide (PBO) and iprobenfos (IBP) synergized imidacloprid activity. The mixtures of imidacloprid and PBO (1 : 1 and 1 : 5) caused 69.4- and 250-fold increase of imidacloprid toxicity against the aphid. Insecticide toxicity of the mixtures of IBP and imidacloprid (1 : 1 and 1 : 5) was also increased 227 and 80.6 times. Esterase activity when $\alpha$-naphtyl butyrate and $\beta$-naphtyl acetate were used as substrates was higher in the resistance strain than in the susceptible one. This means that P450 monooxygenase and esterase are responsible for the resistance to imidacloprid in this aphid strain.

• Korean journal of applied entomology
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• v.31 no.2
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• pp.144-152
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• 1992

The juvenile hormone(JH) titers and juvenile hormone esterase (JHE) activities were mea¬sured in larval homogenates of the chestnut gall waL,J, Dryocosmus kuriphilus Yasumatsu, parasiting a susceptible and two resistant chestnut ( Cheuk-Pa, and Dan- Tak) varieties by GLC, Galleria wax test and Liquid scintilation counter. JH of the chestnut gall wasp was identified as JH- I. Their juvenile hormone titers were 35,800 GU/g(Cheuk-Pa), 30,900 GU/g (Dan-Tak), and 28,600 GU/g(susceptible variety). The juvenile hormone esterase activities were 1.48 n mole/min/ml(Cheuk-Pa), 1.63 n mole/min/ml(Dan- Tak), and 1.89 n mole/mini ml(susceptible variety). JH titer activity of the chestnut gall wasp parasiting resistant varie¬ties were higher than that from susceptible, whereas their JHE activity was higher in those from susceptible variety than those from resitant varieties. JH titer and JH specific esterase activity was inversely proportional.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.2
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• pp.174-176
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• 1991

A electrophoretic study on seveal important enzymes was conducted with seed, leaf and stem of Benincasa hipida (Thunb) Cogn and Commelina communis L. Isozyme patterns of esterase were different from the parts and fruit of wax gourd appeared only one band. In the peroxidase isozyme, fruit of wax gourd appeared four bands, but stem of common dayflower no appeared. In the amylase isozyme, seed and fruit of 'gourd were appeared clearly one band, respectively.

• Molecular & Cellular Toxicology
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• v.2 no.3
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• pp.216-221
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• 2006

The cholinesterase-inhibiting organophosphorous (OP) compounds known as nerve agents are highly toxic. The principal toxic mechanism of OP compounds is the inhibition of acethylcholine esterase (AChE) by phosphorylation of its catalytic site. The reversible competitive inhibition of AChE may prevent the subsequent OP intoxication. In this study, three-dimensional quantitative structure-activity relationship (3D-QSAR) was performed to investigate the relationship between the 29 compounds with structural diversity and their bioactivities against AChE. In particular, predictive models were constructed using the comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA). The results indicate reasonable model for CoMFA ($q^{2}=0.453,\;r^{2}=0.697$) and CoMSIA ($q^{2}=0.518,\;r^{2}=0.696$). The presence of steric and hydophobic group at naphtyl moiety of the model may lead to the design of improved competitive inhibitors for organophosphorous intoxication.

• The Korean Journal of Ecology
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• v.20 no.2
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• pp.103-109
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• 1997

Eleven phenolic compounds including caffeic acid were identified through analyzing the aqueous extracts of Pinus rigida by HPLC. Among them, protocatechuic acid was the maximum amount of 6.84 ppm. Seed germination of Cassia mimosoides var. nomame was significantly stimulated by the extract of P. rigida leaves in the proportion ot concentration. However, root growth was elevalted at a threshold concentration below 25%, but it was inhibited at high concentrations. In 50% extract of P. rigida, upward root tip of C. mimosoides var. nomame showed negageotropism which the root end showed necrosis. New isozyme bands were induced indicating concentration activity of peroxidase from the extract of C. mimosoides var. nomame, especially in the cathodic region. Although it reduced the mumber of isozyme bands of esterase, esterase activities were stimulated in the anodic region of C. mimosoides var. nomame. The activity of amylase was not remarkably different between control and treatment.

• Journal of Sericultural and Entomological Science
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• v.23 no.2
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• pp.11-36
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• 1982

Forty-nine plant species as additives to silkworm artificial diet and 5 species as cellulose sources for artificial diet were screened for their economic values as feed-resources for the silkworm. Feeding response to artificial diet was tested on 82 silkworm strains. The effect of rearing conditions on feeding response and enzyme activities in the silkworm was investigated. The results were summarized as follows. 1. Seven species out of 49, Vigna sinensis ENDL, Ipomoea vatatas Lamarck, Cyperus anuricus Var. Laxus, Alnus japonica Stendel, Trifolium repens L, Prunus serrulata Lindley. Var, Glycine max L increased feeding response, compared with the basic formula of artificial diet. 2. The economic values of Vigna sinensis ENDL, Ipomoea vatatas Lamarck, Cyperus anuricus Var. Laxus, Ainus japonica Stendel, Cassia tera L, Erigeron canedensis L as feed-resources for artificiale diet were recognized, through feeding experiment during the entire larval stage. 3. Mulberry cellulose showed the best results in rearing and cocoon characteristics. 4. The extent of feeding response varied according to strains and varieties. Varieties in japanese strains showed higher feeding response than those in chinese and european varieties, with considerable variations among a varieties in strains. 5. The begining of 4th instar seems to be a proper time to convert from mulberry to artificial diet, or artificial diet to mulberry, however the middle of 3rd instar seems acceptable. 6. The optimum temperature for artificial diet rearing is 30$^{\circ}C$ during the period of 1st-3rd instar and 28$^{\circ}C$ for 4th-5th instar. 7. Electrophoretic isozyme patterns of esterase and acid phosphatase on agarose gel, as affected by strain. rearing temperature and feed-resources, were observed as follow. (1) Isozyme patterns of mid-gut esterase varied, depending on instar. One or two more isozyme bands were observed in the larvae than feed on the mulberry fed for the artificial diet. (2) A strain, chinese-15 with a higher feeding response, had 1∼2 more bands than chinese-60 with a lower feeding response. (3) Five bands of mid-gut esterase in 3rd and 4th instar larvae reared at 28$^{\circ}C$. and 4 for 3rd instar and 6∼7 for 4th instar larvae at 35$^{\circ}C$ were observed. (4) No similar esterase bands could be found among mid-gut, blood and silkgland. There are five esterase bands in the midgut, one in blood and three in silkgland. (5) There was rather small digerence in acid phosphatase types of mid-gut and blood according to varieties and rearing temperature. No active band was shown in silkgland. In midgut, there was one acid phosphatase band at 3rd instar, two at 4th instar and three at 5th instar. In blood, one active band at 3rd or 4th instar and three bands at 5th inster wire detected.

• The Korean Journal of Malacology
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• v.12 no.1
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• pp.39-45
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• 1996

Polyacrylamide gel electrophoresis was used to reveal the esterase isozyme patterns of a freshwater snail, Semisulcospira gottschei, in the lake Uiam. From the result with inhibitors, it is tentatively concluded that four types (arylesterase, carboxylesterase, acethylesterase, acethylcholinesterase)of the adult(means of allele per locus=1.16, %polymorphism=16.7, heterozygosity=0.082)was lower than the juveniles(A=1.7, %P=16.7, H$\sub$D/=0.2215).

• Journal of Microbiology and Biotechnology
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• v.26 no.2
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• pp.315-325
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• 2016

A novel esterase gene, est7K, was isolated from a compost metagenomic library. The gene encoded a protein of 411 amino acids and the molecular mass of the Est7K was estimated to be 44,969 Da with no signal peptide. Est7K showed the highest identity of 57% to EstA3, which is an esterase from a drinking water metagenome, when compared with the enzymes with reported properties. Est7K had three motifs, SMTK, YSV, and WGG, which correspond to the typical motifs of family VIII esterases, SxxK, Yxx, and WGG, respectively. Est7K did not have the GxSxG motif in most lipolytic enzymes. Three additional motifs, LxxxPGxxW, PLGMxDTxF, and GGxG, were found to be conserved in family VIII enzymes. The results of the phylogenetic analysis and the alignment study suggest that family VIII enzymes could be classified into two subfamilies, VIII.1 and VIII.2. The purified Est7K was optimally active at 40ºC and pH 10.0. It was activated to exhibit a 2.1-fold higher activity by the presence of 30% methanol. It preferred short-length p-nitrophenyl esters, particularly p-nitrophenyl butyrate, and efficiently hydrolyzed glyceryl tributyrate. It did not hydrolyze β-lactamase substrates, tertiary alcohol esters, glyceryl trioleate, fish oil, and olive oil. Est7K preferred an S-enantiomer, such as (S)-methyl-3-hydroxy-2-methylpropionate, as the substrate. The tolerance to methanol and the substrate specificity may provide potential advantage in the use of the enzyme in pharmaceutical and other biotechnological processes.

• Korean journal of applied entomology
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• v.36 no.2
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• pp.172-178
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• 1997

There was a great variation in insecticide susceptibilities among field and laboratory populations of the beet armyworm, Spodoptera exigua (Hiibner). Unselected laboratory population, which had been reared for 6-7 generations in our laboratory without exposure to insecticides, was more susceptible than its parental field population in all tested insecticides. Two selected laboratory populations with parathion or deltamethrin showed much higher insecticide tolerance than did the unselected laboratory population in their own selection insecticide. The variation of the insecticide susceptibilities was highly correlated with esterase and acetylcholinesterase activities. Field and the selected laboratory populations had lower acetylcholinesterase activities and higher esterase activities than did the unselected laboratory population. Acetylcholinesterase of the field and the selected laboratory populations had higher Km values than did that of the unselected. In a population, Km values were varied among different developmental stages; acetylcholinesterase of the fifth instar larvae had the highest Km value among those of the other larval stages. Twenty one esterase bands were separated on 6.5% nondenaturing polyacrylamide gel from the whole body extracts of the fifth instar larvae. E2, E7, E8, Ell, El6, and El7 esterase bands were developed more frequently in the insecticides-selected populations than in the unselected population. These results suggest that the variation of insecticide susceptibilities of the beet armyworm includes both biochemical mechanisms: target site insensitivity and enhanced activity of detoxification enzyme.