• Journal of Life Science
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• v.10 no.5
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• pp.496-503
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• 2000

This study was designed to investigate the effects of silkworm (Bombyx mori L.) powder on oxidative stress and membrane fluidity in liver membranes of rats. Sprague-Dawley (SD) male rats (160±10 g) were fed basic diet (control group), and experimental diets (SWP-200 and SWP-400 groups) added 200 and 400 mg/kg BW/day for 6 weeks. A significant differences between liver mitochondria and microsomes of SWP-200 and SWP-400 groups could not be obtained. Membrane fluidities were dose-dependently increased (14.8% and 28.5%, 20.0% and 29.9%) in liver mitochondria and microsomes of SWP-200 and SWP-400 groups compared with control group. Basal oxygen radicals (BOR) in liver mitochondria and mocrosomes were significantly inhibited (15.2% and 21.7%, 12.6% and 18.6%, respectively) by SWP-200 and SWP-400 groups compared with control group. Induced oxygen radicals (IOR) in liver microsomes were significantly inhibited (15.5% and 16.1%, respectively) by SWP-200 and SWP-400 groups compared with control group, but IOR in liver mitochondria was significantly inhibited about 12.0% by SWP-400 group only compared with control group. Lipid peroxide (LPO) levels were significantly decreased (14.4% and 9.1%, respectively) in liver mitochondria and microsomes of SWP-400 group only compared with control group. Oxidized protein (OP) levels were remarkably decreased about 12.7% and 16.3% in liver microsomes only of SWP-200 and SWP-400 groups, but significant difference between liver motochondria could not obtained. These results suggest that administration of SWP may play an effective role in a attenuating a oxidative stress and increasing a membrane fluidity in liver membranes.

• International Journal of Industrial Entomology and Biomaterials
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• v.12 no.2
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• pp.51-56
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• 2006

Use of products containing phytoecdysteroid (PE) as active principle has become popular in prominent sericultural areas of India for hastening larval maturation events and synchronizing cocoon spinning activities as an obvious advantage is assured. At times, the present recommendation of administering PE at the onset of spinning results in peak labour requirement at odd hrs. To enable making recommendation for the use of PE on $multi{\times}bivoltine$ silkworm hybrids based on the climatic conditions prevailing in different areas especially with regard to temperature, the experiment was taken up to determine proper treatment times so that the induced spinning will be more orderly and the labour can be leveraged more efficiently. Different brackets of low ($18-22^{\circ}C$), medium ($24-28^{\circ}C$) and high ($29-32^{\circ}C$) temperature were simulated during the latter half of V larval instar and cocoon spinning. PE was administered to $multi{\times}bivoltine$ silkworm ($BL67{\times}CSR101$) hybrid batches as per the recommended dose at three different times viz., 10 am, 4 pm and 10 pm. Three replicates of 100 larvae were maintained for each treatment. Absolute controls were also maintained in each temperature range to compare the results. Cumulative maturation percentage was recorded at 6 hrs interval to ascertain peak mounting span. The influence of the treatment on the cocoon traits also was studied. Based on the peak mounting span, it was evident that in low temperature 10 pm treatment would be better. In medium and high temperature, treatment at 4 pm proved to be a better option. The influence of the treatment times at different temperature range on labour management is discussed.

• Journal of Sericultural and Entomological Science
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• v.28 no.1
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• pp.24-29
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• 1986

A set of 21 crosses of F1 generation by diallel crosses from seven parent silkworm, Bombyx mori L. were used as materials to estimate genetic parameters such as gene action and combining ability. Experiments were conducted in 1985, and three characters, which are weight of cocoon, weight of cocoon layer and ration of cocoon layer, were observed. The data were analyzed for each character by Jinks', Hayman's and Griffing's methods. The result obtained are summarized as follows : 1. In Vr-Wr graphical analyses, weight of cocoon was found to be inherited in over dominance, and weight of cocoon layer and ration of cocoon layer were observed as partial dominance. 2. Estimate of additive component of variance(D) was greater than those of dominance component of variance(H) for weight of cocoon layer and ratio of cocoon layer, and positive values of F were observed for all characters. 3. Mean squares of general combining ability were higher than those of specific combining ability. 4. Variety Jam 107 was expressed as the highest GCA effects for three characters, and high SCA effects for all characters were observed in combinations of 113 $\times$Jung 14 and Jam 107 $\times$Jung 14.

• Current Research on Agriculture and Life Sciences
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• v.1
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• pp.67-83
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• 1983

The new microsporidia S80 isolated from, Bombyx mori L. in Korea showed ovoid in the morphology of the spores and the size were measured $2.9{\pm}0.28{\mu}$ in length and $1.7{\pm}0.29{\mu}$ width. No other microsporidian spore like this has not been so far isolated from Silkworm. The length of the polar filament extruded in hydrogen peroxide ($H_2O_2$) at $30^{\circ}C$ was $26{\mu}$ of a round cytoplasm on the top. The spores were partly stained with Giemsa, Safranin-O and Gram as the same staining properties as Nosema bombycis, Microsporidia K 79 and other microsporidian spores. The fine structures were observed under scanning eleceron microscope through ultrathin sectioning. The spore wall was composed of three layers ; the thin exospore of an electron dense rippled layer, the thick electron lucent endospore which was thinning considerably at the polar filament insertion point, and the inner limiting membrane. Polar cap present at the sporeapex, with a long polar filament of 12-13 coils, subtending angle of $60^{\circ}$ to spore axis, which is tubular made up of a multilayered and are a benes core, light ring structure enclosing the dance core, the dark ring structure enclosing the inner light ring structure and the other than and light ring structure bounded from cytoplasm. Lamellate polaroplast occupied the anterior part of the spore, and the two neclei with dense nucleoplasm bounded by a double nuclear envelope were cited in the slight downer middle portion of spore. From the characteristics of the shape, size and fine structures, it is certain to reason the Microsporidia S80 belong to the phylum Microspora, class Microspora, order Microsporida, order Microsporida. The shape of two nuclei cited seems to be genus Nosema, but in the classification for the suborder it should be defined wheather pansporoblasts be formed or not and for the genis especial attempts have been made to define the characters which distinguish the disporous genera in the life cycle. Survey through the infection of the bad cocoons during 1980 to 1982 in South Korea the areas contaminated with new microsporidia were revealed 5 provinces of Kyung-Gi, Kang-Won, Chung-Nam and Chun-Nam. Pathological effects inoculated per os at second instar larvae of silkworm, the LD 50 was $7.1{\times}10^7/ml$ as lower pathogenecity than that of Nosema bombycis Naegeli of $1.2{\times}10_7/ml$. While on the other hand the inoculation of the microsporidia at fourth instar larvae lowerd the whole cocoon weight and cocoon shell weight and significant at 1% level. The microsporidia S80 defined it can not be transmitted transovarially from the result of predictive and collective examination of 21 egg batches from the infected female moth.

• Journal of Sericultural and Entomological Science
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• v.16 no.2
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• pp.35-53
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• 1974

A series of experiment was conducted to investigate the effects of the level of dietary Protein (soybean meal) and carbohydrate (sucrose) on the growth rate, feed efficiency, nutrients digestibility and amylase activity of larvae at 5th instar. The results obtained from the experimentation are summarized as follow： (1) It was found that the body weight gain, cocoon quality and feed efficiency of the 5th instar larvae were significantly affected by the level of protein and carbohydrate in the artificial diet. Present data revealed that the proper level of dietary protein and carbohydrate would be the most important factor for the optimum growth of larvae. (2) In the amount of diet consumption, the group of larvae gained more body weight consumed more diet than the group gained less amount of body weight. (3) Digestibility of nutrients was improved as the level of protein in the diet increased, although the level of dietary carbohydrate did not exert any positive results. (4) It was observed that the amylase activity in digestive juice was stimulated by the increasement of dietary carbohydrate. However, no correlation between the level of dietary protein and carbohydrate was detected in the amylase activity. (5) Analytical data indicated that the amount of protein or carbohydrate excreted through feces and urine was proportional to the content of protein or carbohydrate in artificial diet. The group o( larvae consumed the diet contained high protein excreted more protein and less nitrogen free extract than did the group received low protein diet. Likewise, the group of larvae fed high dietary carbohydrate excreted more nitrogen free extract and less protein through excreta than the group consumed low carbohydrate diet group. (6) Although the amylase activity of the larvae received the artificial diet was higher than the larvae received natural diet (mulberry leaf), the rate of body weight gam and the quality of cocoon produced from the natural diet group was better than the artificial diet group. It is, thus, concluded that feeding the larvae by the artificial diet may net be recommendable. (7) It was determined that the best level of protein (soybean meal) and carbohydrate (sucrose) in artificial diet was found to be 40g and 0g, respectively when it was fed to the 5th instar larvae. (8) It may be concluded from the results obtained that the artificial diet that could stimulate the activity of amylase nay not be recommendable for the practical larvae feeding Purpose due simply to the Poor economic return from this diet than natural diet.