• International Journal of Industrial Entomology and Biomaterials
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• v.19 no.1
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• pp.155-164
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• 2009

The most important factors in environment that influence the physiology of insects are temperature and humidity. Insects display a remarkable range of adaptations to changing environments and maintain their internal temperature (thermoregulation) and water content within tolerable limits, despite wide fluctuations in their surroundings. Adaptation is a complex and dynamic state that widely differs in species. Surviving under changing environment in insects depends on dispersal, habitat selection, habitat modification, relationship with ice and water, resistance to cold, diapause and developmental rate, sensitivity to environmental signals and syntheses of variety of cryoprotectant molecules. The mulberry silkworm (Bombyx mori) is very delicate and sensitive to environmental fluctuations and unable to survive naturally because of their domestication since ancient times. Thus, the adaptability to environmental conditions in the silkworm is quite different from those of wild insects. Temperature, humidity, air circulation, gases and photoperiod etc. shows a significant interaction in their effect on the physiology of silkworm depending upon the combination of factors and developmental stage affecting growth, development, productivity and quality of silk. An attempt has been made in this article to briefly discuss adaptation in insects with special emphasis on the role of environmental factors and their fluctuations and its significance in the physiology of mulberry silkworm, B. mori.

• International Journal of Industrial Entomology and Biomaterials
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• v.10 no.2
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• pp.137-141
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• 2005

Though many insecticides are commercially available, development of resistance, pest resurgence and effects on non-target organisms led to the search for alternate insect pest management (IPM) strategy based on larval growth and reproductive fitness. Reproductive potential of insects depends on its acquiring of vitellogenic competence which is under hormonal control. Exogenous application of analogues of JR (JHAs) and ecdysterone could derail normal development and reproduction in insects by manipulating an array of physiological processes. In the rice pest, brown planthopper, Nilaparvata lugens, JHA, hydroprene induced metathetely from the fifth (final) instar nymphs in an age-dependent manner. Day 0 of the final instar showed highest sensitivity to induce this abnormal development. Adults emerged from treated day 3 nymphs looked normal. Both the morphotypes were reproductively incompetent and showed partial to complete sterility. Pre-adult exposure of the ovarian tissue to hydroprene suppressed mitotic division of germinal cells and induced abnormalities in the later s1ages of growth and differentiation of ovary in N. lugens. More over the nymphal exposure to hydroprene inhibited patency changes of follicular epithelium and affected competence of the follicles for yolk sequestration. In the absence of ovarian growth and oocyte differentiation, germarium found disintegrated, trophic core regressed and terminal oocytes resorbed. Hydroprene exposure to newly ecdysed brachypterous females did not affect ovarian development and egg production. Proper larval-adult transition appeared as a. prerequisite for vitellogenic competence in N. lugens for which the ovarian tissues must be exposed to ecdysterone in the internal milieu devoid of JH.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.5
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• pp.764-772
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• 2003

Two genetic constructs used to confer improved agronomic characteristics, namely herbicide tolerance (HT) in maize and soyabean and insect resistance (Bt) in maize, are considered in respect of feeding to farm livestock, animal performance and the nutritional value and safety of animal products. A review of nucleic acid (DNA) and protein digestion in farm livestock concludes that the frequency of intact transgenic DNA and proteins of GM and non-GM crops being absorbed is minimal/non existent, although there is some evidence of the presence of short fragments of rubisco DNA of non-GM soya in animal tissues. It has been established that feed processing (especially heat) prior to feeding causes significant disruption of plant DNA. Studies with ruminant and non-ruminant farm livestock offered GM feeds demonstrated that animal performance and product composition are unaffected and that there is no evidence of transgenic DNA or proteins of current GM in the products of animals consuming such feeds. On this evidence, current HT and Bt constructs represent no threat to the health of animals, or humans consuming the products of such animals. However as new GM constructs become available it will be necessary to subject these to rigorous evaluation.

• Journal of Microbiology and Biotechnology
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• v.4 no.4
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• pp.322-326
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• 1994

Bacillus thuringiensis strain BT-14 was isolated from alfalfa dust in Korea. The strain BT-14 produced one bipyramidal crystal and one spore in the cell. The biochemical characteristics of the strain BT-14 were similar to those of Bacillus thuringiensis subsp. kurstaki HD-l. Examination of its antibiotic resistance revealed that while the strain BT-14 was less resistant than BTK HD-l to ampicillin, gentamycin, neomycin and tobramycin, it was more resistant to amikacin than BTK HD-l. The $\delta$-endotoxin crystal of strain BT-14 consisted of a single protein with a high molecular weight of ca 135 KD on a 10% SDS-PACE. The strain BT-14 contained at least nine different plasmids with sizes of 2.9, 5.3, 5.8, 6.2, 9.4, 15.1, 18.1, 23.1 and 79 Kb. In insect bioassay, the isolated strain BT-14 showed lethality of 67% against Plutella xylostella larvae at dilution of 5$\times$$l0^{-4}$ (5$\times$l0 to 3$\times$$l0^2$ spores/ml), which is, almost equivalent to that of BTK HD-l.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2002.04b
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• pp.19-25
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• 2002

Biotechnology in the 21st century will be driven by three emerging technologies: genomics, high-throughput biology, and bioinformatics. These technologies are complementary to one another. A large number of economically important crops are currently subjected to whole genome sequencing. Functional genomics for determining the functions of the genes comprising the given plant genome is under progress by using various means including phenotyping data from transgenic mutants, gene expression profiling data from DNA microarrays, and metabolic profiling data from LC/mass analysis. The aim of plant molecular breeding is shifting from introducing agronomic traits such as herbicide and insect resistance to introducing quality traits such as healthful oils and proteins, which will lead to improved and nutritional food and feed products. Plant molecular breeding is also expected to aim to develop crops for producing human therapeutic and industrial proteins.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47
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• pp.124-134
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• 2002

The sweetpotato, Ipomoea batatas L. (Lam.), is one of the important summer upland crops in Korea and has been used as human food, industrial yaw material and vegetable. Sweetpotato has been consumed for human foods such as boiled, roasted, fried or salad etc. It should be developed for higher quality as a snack or health food, primarily through improving the eating and marketing qualities as well as nutritional value. Its quality after cooking or processing is a complex one combining the aroma, taste, texture and fiber content. The other important qualities for consumers are root shape, size, skin color, flesh color, insect and disease resistance, nutritional components and safety from phytoalexins(toxic stress metabolites) etc. Korean people generally prefer to red skin color, round or elliptic shape and dry texture, yellow flesh color of sweetpotato which is high in starch content including vitamins and nutrients. The almost factors of quality components of sweetpotato are genetically controlled by breeder, but postharvest handlings and marketing management for making high quality goods should be done thoroughly according to the quality evaluation criteria of sweetpotato from the moment of harvest until shipping them to the market by farmers and the other users. This paper describes current status and prospects of the quality evaluations and researches in sweetpotato roots in Korea.

• Korean Journal of Agricultural Science
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• v.44 no.3
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• pp.348-358
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• 2017

The green peach aphid, Myzus persicae, is one of the most serious insect pest and a vector for a multitude of viral diseases to many crops, vegetables, ornamentals, and fruit trees in the world. A large number of aphids can reduce plant vigor and cause defoliation. Many insecticides have been developed and applied to control the green peach aphid. However, this aphid has displayed a remarkable ability to establish resistance to almost every insecticide. We treated 5 different insecticides registered for M. persicae on pepper leaves and investigated the effects of the insecticides by measuring the time it took to achieve 90% control of the aphids. Acetamiprid worked faster than any other insecticides while cyantraniliprole showed the slowest insecticidal effect. Pymetrozine, pyrifluquinazon, and spirotetramet provided 90% control within similar time. Iwol population's control value was higher than any other populations 24 hours after treatment. When five different unregistered insecticides for M. persicae were treated on pepper leaves, no insecticidal effect was found for gamma-cyhalothrin and novaluron and spinosad showed an insecticidal effect of up to 70% in Iwol population only. Although chlorfenapyr and dinotefuran were not registered for M. persicae, their insecticidal effects were found to be 90% or higher.

• BMB Reports
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• v.37 no.2
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• pp.167-176
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• 2004

Although efficient antiviral lamivudine is used for HBV-infected patients, a prolonged treatment with nucleoside analogs often results in lamivudine-resistant variants. In this study, we evaluated the fidelity of the lamivudine-resistant variants. The FLAG-tagged wild-type (FPolE) and Met550 variants (FPolE/M550A, M550V, and M550I) of HBV DNA polymerases were expressed in insect cells then purified. Like many other reverse transcriptases, no $3'{\rightarrow}5'$ exonuclease activity was detected in the HBV DNA polymerase. Since there is no proofreading activity, then the use of the site-specific nucleotide misincorporation method is beneficial. From the $f_{ins}$ value analysis, it is evident that M550I and M550V exhibit higher fidelity values than the wild-type HBV DNA polymerase, while M550A exhibits similar fidelity values. It is therefore suggested that lamivudine resistance comes from the stringency to dNTP binding and the discrimination of dCTP and lamivudine in M550V and M550I.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.2
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• pp.1-5
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• 1980

Comparisons were made between pubescent and smooth leaved cultivars or lines for the brown planthopper feeding preference, adult emergence percent, nymphal period, grain yield and brown rice recovery percent, and found that there were no significant differences of the traits tested between smooth and pubescent.

• Journal of Plant Biotechnology
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• v.29 no.3
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• pp.145-150
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• 2002

Biotechnology in the 21st century will be driven by three emerging technologies: genomics, high-throughput biology, and bioinformatics. These technologies are complementary to one another. A large number of economically important crops are currently subjected to whole genome sequencing. Functional genomics for determining the functions of the genes comprising the given plant genome is under progress by using various means including phenotyping data from transgenic mutants, gene expression profiling data from DNA microarrays, and metabolic profiling data from LC/mass analysis. The aim of plant molecular breeding is shifting from introducing agronomic traits such as herbicide and insect resistance to introducing quality traits such as healthful oils and proteins, which will lead to improved and nutritional food and feed products. Plant molecular breeding is also expected to aim to develop crops for producing human therapeutic and industrial proteins.