• Journal of Plant Biology
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• v.19 no.1
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• pp.14-18
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• 1976

Inhibition of flowering in Lemna perpusilla 6746 by 30 mM sucrose was reversed by the addition of acetylcholine (>$10^{-4}M) supplemented with 10^{-4}M$ ascorbic acid to 1/10-strength Hunter's growth medium. The reversible effect of acetylcholine was found to be greater at early stages of flowering than in the later period. Promotive effects of both acetylcholine ($10^{-3}M) and eserine(10^{-5}M$) on flowering in the short-day plant under various photoperiodic conditions were studied. It was indicated that the application decreased length of the critical dark period for the floral induction, and it was also shown that the endogenous status of acetylcholine was involved in the floral response which had a correlation with phytochrome. Interruption of inductive dark periods by red irradiation (1min) immediately followed by far-red light (1 min) completely inhibited flowering, while the addition of acetylcholine and eserine to the medium under the same condition slightly promoted flowering, indicating possible involvement of phytochrome system in acetylcholine activity for photoperiodic sensitivity of floral response in Lemna perpusilla 6746.

• The Korean Journal of Pesticide Science
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• v.11 no.3
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• pp.171-178
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• 2007

Esterase isozymes were extracted from final instar larvae of M. saltuarius treated with selective diets and inhibitors. Twenty esterase isozymes were separated on 12% native-PAGE gel and stained with three different substrates(${\alpha}$-naphthyl acetate, ${\beta}$-naphthyl acetate, or ${\alpha}$-naphthyl butyrate). Interestingly, the isozymes of Est7(${\alpha}$-naphthyl acetate and ${\alpha}$-naphthyl butyrate) and Est6(${\beta}$-naphthyl acetate) were specifically activated in final instar larvae fed with the bark of Pinus koraiensis. However, we could not find any band from substrate ${\beta}$-naphthyl stearate. The esterase activities of Est3, Est6, and Est7 were inhibited by organophosphate and carbamate insecticides. In addition, The esterase activities of Est4, Est6, and Est7 were also inhibited by eserine. However, inhibition of esterase activities in methoprene, bornyl acetate, linal, cineol, and citral was not observed. However, It is necessary to reconfirm these results in vivo.

• BMB Reports
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• v.43 no.8
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• pp.573-578
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• 2010

Several organophosphorus (OP) insecticides can selectively kill the silkworm maggot, Exorista sorbillans (Es) (Diptera: Tachinidae), while not obviously affecting the host (Bombyx mori) larvae, but the mechanism is not yet clear. In this study, the cDNA encoding an acetylcholinesterase (AChE) from the field Es was isolated. One point mutation (Gly353Ala) was identified. The Es-353G AChE and Es-353A AChE were expressed in baculovirus-insect cell system, respectively. The inhibition results showed that for eserine and Chlorpyrifos, Es-353A AChE was significantly less sensitive than Es-353G AChE. Meanwhile, comparison of the I50 values of eserine, dichlorvos, Chlorpyrifos and omethoate of recombinant Es AChEs with its host (Bombyx mori) AChEs indicated that, both Es AChEs are more sensitive than B. mori AChEs. The results give an insight of the mechanism that some OP insecticides can selectively kills Es while without distinct effect on its host, B. mori.

• The Korean Journal of Pesticide Science
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• v.11 no.3
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• pp.179-185
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• 2007

Esterase isozymes were investigated from digestive juice of M. saltuarius adults after pesticide treatment. Twelve esterase isozymes were separated on 12% native-PAGE gel and stained with three different substrates(${\alpha}$-naphthyl acetate, ${\beta}$-naphthyl acetate, and ${\alpha}$-naphthyl butyrate). Interestingly, the isozyme of Est1(${\alpha}$-naphthyl acetate) was strongly inhibited by the carbofuran and methomyl. The Est1 activity was completely inhibited by the chlorpyrifos and partially inhibited by methidation about 70 %. In addition, eserine suppressed esterase isozyme activities of Est1 about 70% and isozyme activities of Est2, Est3, and Est4 were weakly inhibited. ${\alpha}$-pinene did not suppressed esterase isozyme activities but activities of esterases were very weakly inhibited in camphor and bornyl acetate.

• Parasites, Hosts and Diseases
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• v.31 no.4
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• pp.321-330
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• 1993

F. seoulensis were obtained from artificially infected albino rats at 3, 4, 5, 6, 7 days after infection. The worms and metacercariae were washed in physiological saline solution, and fled with 10% neutral formalin. The acetylcholinesterase (AchE) stained by one histochemistry using acetylthiocholine iodide as substrate. Eserine, ism-OMPA and BW284C51 were used as inhibitors of AchE. The nervous system consists of three pairs longitudinal nerve trunks interconnected with excretory plexus in posterior half, and phinmc and oral sucker in anterior half of metacercariae and adults. The longitudinal nerve trunks are interconnected with transverse commissures and numerous circular commissures. Considerable numbers of circular commissures are interconnected with longitudinal nerve trunks tying on the surface of the worms. At each stage of juvenile worms, AchE and nonspecific cholinesterase activites were observed in the oral sucker, ventral sucker, pharynx and nerve system. Isoxymes of AchE in f seoderuts were separated into the two bands, 69 kDa and 132 kDa. The major band was 69 kDa.

• Journal of the Korean Society of Tobacco Science
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• v.21 no.1
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• pp.49-56
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• 1999

Classification of esterase isozymes of the apterous green peach aphids (Myzus persicae Sulzer) collected in tobacco fields were investigated by the native polyacrylamide gel electrophoresis (PAGE). A total of twelve esterase bands were identified in adult apterous aphid, and the difference of enzyme band activity in the clones was observed at the first and second bands group. Esterases of green peach aphids reacted with specific substrate were more stained $\alpha$-naphthyl acetate than $\alpha$-naphthyl propionate, and $\alpha$-naphthyl acetate more than $\beta$-naphthyl acetate. Twelve esterases on the basis of inhibition by the three types of inhibitors (organophosphates: 2.5$\times$10$^{-3}$ M paraoxon, 4$\times$10$^{-3}$ M DFP; eserine sulfate : 2$\times$10$^{-3}$ M eserin; sulfhydryl reagents: 2$\times$10$^{-3}$ M p-HMB) were classified into three class, namely, cholinesterase (ChE) I, II, carboxylesterase (CE) and arylesterase (ArE), and these classes contained 3, 4, 3 and 2 isozymes, respectively.

• Toxicological Research
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• v.22 no.1
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• pp.1-8
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• 2006

The primary metabolism of pyribenzoxim was studied in rat liver microsomes in order to identify the cytochrome P450 (CYP) isoform(s) and esterases involved in the metabolism of pyribenzoxim. Chemical inhibition using CYP isoform-selective inhibitors such as ${\alpha}$-naphthoflavone, tolbutamide, quinine, chlorzoxazone, troleandomycin, and undecynoic acid indicated that CYP1A and CYP2D are responsible for the oxidative metabolism of pyribenzoxim. And inhibitory studies using eserine, bis-nitrophenol phosphate, dibucaine, and mercuric chloride indicated pyribenzoxim hydrolysis involved in microsomal carboxylesterases containing an SH group (cysteine) at the active center.

• Journal of the Korean Society of Tobacco Science
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• v.20 no.1
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• pp.80-86
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• 1998

Changes in activity and classification of esterase isozymes during the tire cycle or Plodia inteipunctella (Hiibner) were investigated by the native polyacrylamide gel electrophoresis. The stage specificity in esterase activity and isozyme pattern was observed throughout the larvalpupal-adult transformation. The activity esterase was highest at the 3-day old adult stage, and the lowest level at the prepupal stage. A total of 12 esterase bands were identified throughout the development, and the bands showing high enzyme activity was observed in the middle part of gel. Twelve esterases on the basis of inhibition by the three types of inhibitors (organophosphates, eserine sulfate and sulfhydryl reagents) were classified into three class, namely, carboxylesterase (CE), arylesterase (ArE) and cholinesterase (ChE), and these classes contained 7, 3 and 2 isozymes, respectively.

• The Korean Journal of Zoology
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• v.39 no.2
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• pp.190-197
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• 1996

The optimal conditions and substrate specificity of whole body esterase (EST) activity, effects of inhibitors (Eserine, Paraoxon, p-HMB, DDVP, DFP) on the enzyme, and ontogenv of the isozymes were determined in Lucilio ilfustris Meisen. The optimal temperature was $45^{\circ}C$ regardless of kind of reacted substrate, $\alpha-naphthyl$ acetate $(\alpha-Nal,$ a.naphthvl butylate $(\alpha-N),$ and Pnaphthyl acetate $(\beta-Na),$ but the optimal pH showed some regioselectivitv to naphthvl group of the esters; PH 7.0 for Iform, pH 7.5 for a-form. The maximum reaction rate was recorded at about 2.5 $\times$ 10's M of PNa and etNa, but 1.0 $\times$ 10'S M of $\alpha-Nb.$ Among the five EST inhibitors tested, DDVP was the most powerful. However, distinction of the relative specificity of inhibitors between three body parts, head, thorax, and abdomen, was shouts, representing differences in the distribution and activity of isozvmes. Of 12 carboxyl-esterases (CE), 8 cholinesterases (ChE) and 2 arvlesterases (ArE) identified based on their inhibitor specificity throughout the development, two larval and prepupal stage specific ChEs, no pupal specific, and 2 CEs.2ChEs. and one ArE adult specific isozvmes were confirmed.

• Mycobiology
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• v.43 no.2
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• pp.137-149
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• 2015

In the search for novel potent fungi-derived bioactive compounds for bioinsecticide applications, crude ethyl acetate culture filtrate extracts from 110 mangrove fungal endophytes were screened for their toxicity. Toxicity tests of all extracts against brine shrimp (Artemia salina) larvae were performed. The extracts with the highest toxicity were further examined for insecticidal activity against Spodoptera litura larvae and acetylcholinesterase (AChE) inhibition activity. The results showed that the extracts of five isolates exhibited the highest toxicity to brine shrimp at 50% lethal concentration ($LC_{50}$) values of 7.45 to 10.24 ppm. These five fungal isolates that obtained from Rhizophora mucronata were identified based on sequence data analysis of the internal transcribed spacer region of rDNA as Aspergillus oryzae (strain BPPTCC 6036), Emericella nidulans (strains BPPTCC 6035 and BPPTCC 6038), A. tamarii (strain BPPTCC 6037), and A. versicolor (strain BPPTCC 6039). The mean percentage of S. litura larval mortality following topical application of the five extracts ranged from 16.7% to 43.3%. In the AChE inhibition assay, the inhibition rates of the five extracts ranged from 40.7% to 48.9%, while eserine (positive control) had an inhibition rate of 96.8%, at a concentration of 100 ppm. The extracts used were crude extracts, so their potential as sources of AChE inhibition compounds makes them likely candidates as neurotoxins. The high-performance liquid chromatography profiles of the five extracts differed, indicating variations in their chemical constituents. This study highlights the potential of culture filtrate ethyl acetate extracts of mangrove fungal endophytes as a source of new potential bioactive compounds for bioinsecticide applications.