• 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.

• Journal of Animal Science and Technology
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• v.48 no.1
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• pp.77-90
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• 2006

The purpose of this study was to isolate cellulolytic and hemicellulolytic anaerobic bacteria inhabiting from gut of ruminants and investigate their hydrolytic enzyme activities. Extracellular CMCase activities of H-strains isolated from the rumen of a Holstein dairy cow were higher than those of D- and DC- strains from the rumen and large intestine of Korean spotted deer. Most isolated bacteria utilized more efficiently Dehority's artificial medium containing starch, glucose and cellobiose (DAS) than those in Dehority's artificial medium containing cellulose only (DAC). The results of biochemical reactions and sugar fermentation indicated that the isolated bacteria belong to one of bacterial strains of Peptostreptococcus spp., Bifidobacterium spp., Prevotela ruminicola/buccae, Clostridium beijer/butyricum and Streptococcus intermedis which are not highly cellulolytic. Activities of Avicelase, xylanase, β-D-glucosidase, α-L-arabinofuranosidase and β-xylosidase of the isolated anaerobic bacteria in DAS were higher than those in DAC. In conclusion, the results indicated the higher enzyme activities of the isolated strains cultured in DAS medium were mainly caused by their specific carbohydrate utilization for enzyme production and growth rate. The highly cellulolytic bacteria were not isolated in the present experiment. Thus further research is required to investigate characteristics of gut bacteria from Korean spotted deer.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.5
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• pp.542-550
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• 1996

An experiment with alfalfa (Medicago sativa L.) plants was designed to investigate the changes in non-structural carbohydrate (NSC) contents and the activities of amylolytic enzymes during a regrowth period following defoliation. Sampling from hydroponic grown-plants were carried out at intervals during 24 days of regrowth. Shoot regrowth was very slow during the first 10 days and root growth was depressed after defoliation. Defoliation induced a great decrease in both total sugar and starch contents in taproots during the first 10∼14 days. A major recovery of NSC occurred from day 15. Averaged over sampling dates, the activity of exo-amylase was about 400-fold higher than that of endo-amylase. Exo-amylase activity in defoliate plants slightly increased until day 6 (maximum level) and then decreased. Endo-amylase rapidly increased for the first 4 days after defoliation and slightly increased afterwards to a maximum on day 24. These results showed that increase in amylolytic enzyme activity in taproots coincided with the time of starch utilization during regrowth and that indicated it plays an important role in starch degradation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.1
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• pp.65-69
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• 1991

In order for investigating the factors related to decrease of seedling vigor in the naked barley lines, two naked lines and a covered variety were sprouted with 20 mm rainfall in the natural condition, dried and the sprouted seeds were threshed by hand and small machine thresher, Chiyota. In the case of hand-threshing of the sprouted seeds, the germination rate index (GRI), germination rate, and TTC test value of the different varieties were not different due to the different sprouting degrees, but emergence rate index (ERI) became decreased with stronger sprouting damage. In comparison with hand-threshing, the embryos of sprouted seeds from machine threshing with 700 rpm were partially damaged, and the traits related to seedling vigor were decreased highly significantly. However, the diastatic activity was sharply increased by stronger sprouting and machine threshing. The sprouting degree in the hand-threshing plot was significantly correlated with the diastatic activity(r=0.931＊＊, 0.951＊＊) and GRI(r=0.461), respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.1
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• pp.15-24
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• 2011

The glutathione (GSH) concentration in leaves of different maturities and roots of forage rape (Brassica napus L.) supplied with four levels of external $SO_4^{2-}$ (0, 0.1, 1.0 and 2.0 mM) supply were measured. The relationships of GSH concentration with $SO_4^{2-}$ uptake, ATP sulfurylase (ATPS) and O-acteylserine (thiol) lyase (OASTL) activity were also assessed. The $SO_4^{2-}$ uptake increased in parallel with the external $SO_4^{2-}$ supply, while protein concentration was not significantly changed. The ATPS activity increased continuously with decreasing $SO_4^{2-}$ supply from 2.0 to 0 mM, while the OASTL activity decreased significantly only at S-deficient conditions (0 and 0.1 mM). The GSH concentration in the young leaves, middle leaves and roots continuously increased (except for between 1.0 and 2.0 mM in the middle leaves and roots) as the external S supply was increased, but no significant changes occurred in the old leaves. The increased endogenous GSH concentration, affected by the $SO_4^{2-}$ supply level, was significantly related with the decrease in ATPS activity in both leaves and roots, and the decrease in OASTL activity only in leaves..

• Current Research on Agriculture and Life Sciences
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• v.6
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• pp.157-162
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• 1988

In order to study of practical purpose of immobilized Mucor spp L42 milk clotting enzyme on activated succimylamino-propyl glass beads with glutaraldehyde in continuous curd coagulation, acidified milk(pH5.6, $8^{\circ}C$) was treated through reactor packed with immobilized beads, and warmed at $30^{\circ}C$ and allowed to coagulation for the determination of enzyme stability, deactivation of milk clotting ability by continuous reaction, the beads treatment conditions, and contact time of milk and beads in reactors. The results obtained were summarized as follow ; 1) After 3 month's storage, activity of immobilized Mucor spp L42 milk clotting enzyme in 0.2M phosphate buffer(pH 4.6) with 0.06% sodium azide was only 80% of initial activity. 2) Milk clotting activity of the beads was decreased by continuouse exposure on acidified skim milk. Nitrogen accumulation on the beads paralled loss of the activity in initial reaction stage. 3) After 6 hours continuous treatment of the beads at 60 sec/ml surface time, the milk-clotting activity of the beads was about 70% of initial activity. 4) Bead reactor and shaking bed reactor were more effective than column reactor on continuouse skim milk coagulation.

• Current Research on Agriculture and Life Sciences
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• v.3
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• pp.166-173
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• 1985

Several enzyme immobilization methods has been compared for immobilization of pepsin. Carboxymethyl cellulose and diethylaminoethyl cellulose were activated with Hcl and with NaOH, and were used for immobilization of pepsin. Sepharose-4B was activated cyanogen bromide, and was used for immobilization of pepsin. Porous glass beads were derivatized with 3-aminopropyitrlethoxysilane and with succinicanhydride, and were used for immobilization of pepsin. The results abtained were summarized as follow, 1. 10 mg/gr. dry bead and 15mg/gr. dry bead of pepsin were absorbed to CM-cellulose and DEAE-cellulose, 20 mg/gr. dry bead and 27 mg/gr. dry bead were coupled to CM-cellulose and DEAE-cellulose with glutaraldehyde respectively. Enzyme yields were 22% and 24% of soluble pepsin. 2. 16 mg/gr. dry bead of pepsin was attached to cyanogen bromide activated sepharose-4B, 19mg/gr. dry bead was cross linked to the activated bead with glutaraldehyde. Immobilized enzyme activity was 23% of soluble pepsin. 3. 40 mg/gr. dry bead of pepsin was conjugated to the derivatized glass beads. Immobilized enzyme activity was 45% of soluble pepsin.

• Journal of Life Science
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• v.17 no.12
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• pp.1660-1668
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• 2007

The non-ionic surfactant (NIS) Tween 80 was evaluated for its ability to influence invitro cumulative gas production, dry matter digestibility, cellulolytic enzyme activities, anaerobic microbial growth rates, and adhesion to substrates by mixed rumen microorganisms on rice straw, alfalfa hay, cellulose filter paper and tall fescue hay. The addition of NIS Tween 80 at a level of 0.05% increased significantly (P<0.05) in vitro DM digestibility, cumulative gas production, microbial growth rate and cellulolytic enzyme activity from all of substrates used in this study. In vitro cumulative gas production from the NIS-treated substrates; rice straw, alfalfa hay, filter paper and tall fescue hay was significantly (P<0.05) improved by 274.8, 235.2, 231.1 and 719.5% compared with the control, when substrates were incubated for 48 hr in vitro. The addition of 0.05% NIS Tween 80 to cultures growing on alfalfa hay resulted in a significant increase in CMCase (38.1%), xylanase (121.4%), Avicelase (not changed) and amylase (38.2%) activities after 36 h incubation. These results indicated that the addition of 0.05% Tween 80 could greatly stimulate the release of some kinds of cellulolytic enzymes without decreasing cell growth rate in contrast to trends reported with aerobic microorganism. Our SEM observation showed that NIS Tween. 80 did not influence the microbial adhesion to substrates used in the study. Present data clearly show that improved gas production, DM digestibility and cellulolytic enzyme activity by Tween 80 is not due to increased bacterial adhesion on the substrates.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2002.05a
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• pp.30-30
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• 2002

• Korean Journal of Food Science and Technology
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• v.23 no.4
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• pp.452-458
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• 1991

Psychrotrophs producing protease were isolated during ripening periods of Cheddar cheese and one of them containing the highest protease activity was identified as Pseudomonas fluorescens 65. The extracelluar proteolytic enzyme was partially purified from P. fluorescens 65 through the Sephadex G-100 gel filtration. The protease was eluted between 190 ml and 230 ml of elution volume of sodium phosphate buffer. The purified protease showed a single band in SDS-PAGE and its molecular weight was 47,000. The composition of amino acid for the protease was determined and the most abundant amino acids were glutamic acid (14.96%) and serine (13.86%). The optimum temperature and pH for the activity was $45{\sim}50^{\circ}C$ and 6.0, respectively.