• Korean journal of applied entomology
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• v.33 no.2
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• pp.81-87
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• 1994

The experiments were canied out to investigate the toxicological characteristics of Insect Growth Regulators (IGRs) such as chlorfluazuron, diflubenzuron, pyriproxyfen and tebufenozide against the various stages of instars of fall webwom (Hyphantrio cuneo Dmy) and nce stem borer (Chiio suppressaiis Walker). In fall webwom, the tolerance ratio m) with the 2nd-6th instars, as cornpared with LCso of the 1st instar, ranged 107-358, 1.13-6.06, 1.02-3.23 and 1.05- 6.64, respectively. In the rice stern borer, the TR of the 3rd instar, as compared with LCso of the 1st instar, to chlorfluazuron, diflubenzuron, pyriproxyfen and tebufenoz~de were 2.86, 260, 19.80 and 15.30, respectively.

• The Korean Journal of Zoology
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• v.24 no.1
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• pp.27-37
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• 1981

Protein patterns at various stages of pre-and post-fertilization in Drosophila melanogaster were analyzed using polyacrylamide gel electrophoresis. Ovaries at various times after hatching, embryos, larvae and pupae were collected and used for protein analysis. The protein patterns were found to vary qualitatively and quantitatively during oogenesis as well as during embryogenesis and metamorphosis. Yolk proteins, which were found to be synthesized in fat body and transferred into the oocytes, appeared in three bands in the gel in the early stages, but these proteins seemded to be converged into a single band in the late stage of oogenesis. The protein patterns in the post fertilization stages seemed to be abruptly changed at two different stages; between embryonic and larval stages and between the second and third instar stages. The pattern in the pupal stages was not very much different from that of the third instar.

• Applied Microscopy
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• v.12 no.2
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• pp.69-79
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• 1982

In order to define the morphological changes of the secreting cells of prothoracic gland during larva-pupal molt, ultrastructural observations were carried out using Bombyx mori L. as the experimental material. At first stage of present experiment, 4 day old 5th instar larva, the polyhedral secreting cells were centrally located in the prothoracic gland surrounded by the connective sheath. The secreting cells were attached to the neighboring cells by the prominent desmosomes, and the plasma membrane contacted with connective sheath were highly infolded. In cytoplasm, the most of the cell organelles, such as rod-like mitochondria, rough surfaced endoplasmic reticulum, ribosome were developed. As the stages advance from larva to pupa, general feature of the secreting cells were retained, but structural changes of the various cytoplasmic organelles-ribosome, rough surfaced endoplasmic reticulum, mitochondria, Golgi apparatus, lamellar body, and vesicle-were noted. In the perinuclear cytoplasm of the secreting cells at the stage of 6 day old 5th instar larva, it is peculiar that only a large amount of ribosomes were distributed and the other organelles were retreated from the juxtanuclear region. Just before and after spining cocoon, these features were more remarkable. Rough surfaced endoplasmic reticulum were gradually increased from the stage just before spining cocoon to the pharate pupa. Rod-like mitochondria with irregular cristae and the matrix showing low density were distributed throughout the cytoplasm in the secreting cells of the 4 day old 5th instar larva. Sometimes, longitudinally distended and curved mitochondria were observed. At the stage of pharate pupa, most of mitochondria were deformed. The rod-like mitochondria of the secreting cells of pupal prothoracic gland were narrower than those of 4 day old 5th instar larva, and the electron density of the mitochondrial matrix is increased in pupa. Golgi apparatus were a few in number in both stages, last instar larva and spining cocoon. In stages of the pharate pupa, the Golgi apparatus were frequently observed. Cytoplasmic vesicles were observed for the first time in the secreting cells of one day after spining cocoon, and the number and the size of cytoplasmic vesicles were distinctly increased inpharate pupa and just after pupation. In the secretory cells of the PG, it in concluded that the RER was closely related to syntheting the enzymes seem to produce the ecdysone.

• The Korean Journal of Zoology
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• v.16 no.3
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• pp.185-191
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• 1973

The soluble whole body proteins of meal-worm Ephestia kuhniella, at various developmental stages have been studied by means of acrylamide gel disc electrophoresis. A maximum of eighteen bands were observed in the male of the 6th instar larva and the female of the late pupa. In general, the protein bands increased with the growth of larva, decreased at the prepupal stages, and at the pupal stages they increased again. The possible significance of these observations has been discussed. In addition, comparisons have been made of the protein patterns between the males and females in the developmental stages.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.2
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• pp.195-199
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• 2002

In order to find potential anticancer agents, we extracted pheophytin in the silkworm feces from various larval stages by water, chloroform and methanol extraction. The cytotoxicity of the pheophytin extracts of various silkworm feces was measured in the CT-26 cells originated from murine metastatic colon cancer, by dye uptake assay. The cytotoxicity of those pheophytins in 2nd, 3rd and 4th instars was better than remaining larval stages. The in vitro anticoagulant and fibyinolytic activities of ethanol extract from varietal mulberry leaves, mulberry branches and silkworm feces and pheophytin extracts from silkworm feces obtained at various larval stages were evaluated in order to find effective therapeutic drugs for the treatment of myocardial and cerebral thrombosis. The fibrinolytic activity was tested using the activated partial thromboplastin time (APTT) and thrombin time (TT) was measured for blood clotting activity. With regards to the fibrinolytic system, ethanol extracts of silkworm feces were better than varietal mulberry leaves and mulberry branches. The pheophytin extracts from 7th days of 5th instar contained the highest percentage of pheophytin and good fibrinolytic activity.

• Journal of Microbiology and Biotechnology
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• v.30 no.9
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• pp.1367-1378
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• 2020

The polyphagous eri silk moth, Samia ricini, is associated with various symbiotic gut bacteria believed to provide several benefits to the host. The larvae of S. ricini were subjected to isolation of gut bacteria using culture-dependent 16S rRNA generic characterization, metagenomics analysis and qualitative enzymatic assays. Sixty culturable aerobic gut bacterial isolates comprising Firmicutes (54%) and Proteobacteria (46%); and twelve culturable facultative anaerobic bacteria comprising Proteobacteria (92%) and Firmicutes (8%) were identified inhabiting the gut of S. ricini. The results of metagenomics analysis revealed the presence of a diverse community of both culturable and un-culturable gut bacteria belonging to Proteobacteria (60%) and Firmicutes (20%) associated with seven orders. An analysis of the results of culturable isolation indicates that these bacterial isolates inhabited all the three compartments of the gut. Investigation on persistence of bacteria coupled with metagenomics analysis of the fifth instar suggested that bacteria persist in the gut across the different instar stages. In addition, enzymatic assays indicated that 48 and 75% of culturable aerobic, and 75% of anaerobic gut bacterial isolates had cellulolytic, lipolytic and nitrate reductase activities, thus suggesting that they may be involved in food digestion and nutritional provision to the host. These bacterial isolates may be good sources for profiling novel genes and biomolecules for biotechnological application.

• Korean Journal of Environmental Biology
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• v.22 no.2
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• pp.321-328
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• 2004

The effects of Di (2-ethylhexyl) phthalate (DEHP) on the fourth instar larvae of Chironomus riparius were tested in the laboratory. Employing a waterreplacement exposure setup, chironomids were subjected to various concentrations. In the most treatments mortality reached a statistically significant difference from the control conditions. As DEHP concentrations were increased, the rates of emerged adults decreased. Sex ratio was unaffected with little deviation from a 1:1 relationship (except in 1 and $30\mu{g}\;L^{-1})$. The developmental stages was delayed at low concentration (0.3 and $1\mu{g}\;L^{-1})$. Generally the emergent period was different between males and females, and the first emergent day of males was faster than females. The body shape of female adults was larger than males. Differences between males and females were found in body volume, body length and body width. In addition, the body volume showed the significant difference between controls and treatments, and those especially well observed females.

• Korean journal of applied entomology
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• v.49 no.3
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• pp.199-204
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• 2010

The seasonal fluctuation of the large 28-spotted lady beetle, Henosepilachna vigintioctomaculata (Motschulsky), was observed in potato fields of Gangneung region, Gangwondo Province. The effects of their leaf consumption over a 24 hour period and developmental periods by different temperatures were investigated, and then the developmental threshold (DT) and effective cumulative temperature (ET) of each stage were calculated. Various developmental stages of H. vigintioctomaculata were captured in the fields from May to September, with three peaks in late May, late June, and late August. Leaf consumption by larval stages increased with the development of instar. The 4th instar larvae consumed potato leaves much more than other stages. Egg hatchability and emergence rate of H. vigintioctomaculata were lower at $10^{\circ}C$ and $30^{\circ}C$, but higher at around $20{\sim}23^{\circ}C$. The developmental periods of each stage became shorter as temperature increased; 90 days at $10^{\circ}C$, 40 days at $20^{\circ}C$ and 25 days at $25^{\circ}C$. Base on developmental velocity to temperature, calculated DT and ET were $7.3^{\circ}C$ and 83.

• Korean journal of applied entomology
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• v.35 no.3
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• pp.249-253
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• 1996

In the laboratory study, the toxicities of chlorpyrifos-methyl, chlorpyrifos, etofenprox, etofenprox+PAF' and deltamethrin for different larval instars of S. litura decreased significantly as larvae aged. LCso values for chlorpyrifos- methyl and chlorpyrifos increased significantly from 3rd instar larvae, while those for etofenprox+PAP and deltamethrin-increased from 2nd instar larvae. In pot study, no significant differences in control efficacy were observed among each treated plots and over 90% control efficacy at 5 d after treatment was obtained in all of the treated plots, except treatment with deltamethrin. Therefore four insecticides excluding deltamethrin will be effective for controlling S. litura. However, it will be probably important to select appropriate insecticides and decide a proper time of treatment because the developmental stage is a significant factor in deciding insecticide efficacy because various developmental stages of the tobacco cutworm inhibit in fields.

• The Korean Journal of Zoology
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• v.36 no.3
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• pp.373-379
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• 1993

The heat shock protein (HSP) genes are expressed at various stages of the Drosophila life cycle even under non-heat-shock conditions. In the present study, developmental changes of HSP23 gene expression and the role of 20-hydroxyecdysone (2OHE) on the HSP23 gene expression were investigated in Drosophila melanogaster. The Northern blot and Western blot analyses showed that HSP23 gene expression occurred at the early third instar larval stage, reached the highest with a sharp peak in the white prepupa, and then decreased throughout the pupal period. When the HSP23 gene expression was compared with the secretion of 20HE, there is a slmiladty between 20HE synthesis and HSP23 gene expression during the third instar larval-prepupal period. It appears that 2OHE regulates expression of HSP23 gene at larva-pupa molting period, and that, 2OHE is also involved in the control the metamorphosis in some part through the HSP23.