• Journal of Sericultural and Entomological Science
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• v.15 no.1
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• pp.1-7
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• 1973

his study has been carried out to investigate amylase activity of digestive juice in the 5th day of the 5th instar influenced by the dietary composition (quantitative ratio between carbohydrate and protein) and the rearing temperature during the 4th moulting period. The larvae grew on three kinds of semi-synthetic diets. The A-diet has more carbohydrate than the others, the B-diet has carbohydrate in 1 : 2 with protein, and the C-diet has more protein than the others. All the diets were kept at 16$^{\circ}C$, 25$^{\circ}C$ and 32$^{\circ}C$ during the 4th moulting period. Amylase activity of digestive juice at the 5th day of the 5th instar was analyzed by Fuwa's method. The results were as follows. 1. Both A and C-diets were worse than B-diet in the larval growth and development. 2. The dietary composition influencing amylase activity of digestive juice was not related to the rearing temperature during the 4th moulting period. Amylase activity was stronger in C-diet, B-diet and A-diet order. 3. It was found that amylase activity at 32$^{\circ}C$ was stronger than that at 16$^{\circ}C$ in all kinds of diets. 4. There was an inter-action in amylase activity of male larval digestive juice between the dietary composition and the rearing temperature during 4th the moulting period.

• International Journal of Industrial Entomology and Biomaterials
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• v.22 no.1
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• pp.1-4
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• 2011

This study was conducted to test the use of colored cocoon silkworm, Golden Silk, as a host for the fruiting body production of Cordyceps mushroom. Golden Silk variety had a shorter larval period than Yangwonjam at $25.3^{\circ}C$ and 78.5% RH: The average larval period of the Golden Silk was 24 days and 7 hr, and that of the Yangwonjam was 24 days and 15 hr. In the infection test of I. tenuipes on silkworm, the larval period of normal silkworms was longer than the silkworms inoculated with I. tenuipes in both Golden Silk and Yangwonjam. The pupae survival percentage of Golden Silk was 94.4%, whereas it was 91.9% in Yangwonjam. Golden Silk had a higher pupation rate than Yangwonjam. The pupation rate of normal silkworms was about 5% higher than that of silkworms inoculated with I. tenuipes. Infection rate of I. tenuipes into larvae of 5th instar newly exuviated silkworm was 93.8% in Golden Silk, and 96.9% in Yangwonjam. Synnemata production of I. tenuipes was better in Yangwonjam with an incidence rate of 99.8% than Golden Silk with 98.6%. The average synnemata weight of Golden Silk was 1.12 g and that of Yangwonjam 1.29 g. Golden Silk had a lower synnemata weight than Yangwonjam. But no significant difference was observed in synnemata weight varieties. The synnemata of I. tenuipes produced on pupae were white or milky-white in color, and similar in shape and color to wild synnemata collected in Korea.

• Journal of Sericultural and Entomological Science
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• v.45 no.1
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• pp.6-9
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• 2003

This experiment was done to know developmental characteristics of Sericin jam. Incubation periods were 10 day 2 hr, and 10 day 1 hr. 11 day 1 hr for Nd-s jam, N $d^{H}$ jam, and Baegok jam, respectively. Hatching rates were 83.9, 83.3 and 96.0% for Nd-s jam, N $d^{H}$ jam, and Baegok jam. Larval periods were, 20 days 1 hr for Nd-s jam, 20 days 5 hrs for N $d^{H}$ jam, and 22 days 12 hrs for Baegok jam. Death rate of larvae was highest in N $d^{H}$ iam, followed by Nd-s jam and Baegok jam. Pupation rate was highest in Baegok Jam followed by Nd-s jam and that of N $d^{H}$ jam was the lowest among the three. Cocoon weight was 1.39, 1.08, and 2.01 g for Nd-s jam, N $d^{H}$ jam, and Baegok jam, respectively. Shell weight were 13, 3, and 48 cg for Nd-s jam, N $d^{H}$ jam, and Baegok jam. Cocoon shell ratios were 9.0% for Nd-s jam, 2.8% for N $d^{H}$ jam and 23.9% for Baegok jam. Cocoon sizes were 30.6${\times}$15.8 mm for Nd-s jam, 24.7${\times}$14.9 mm for N $d^{H}$ jam and 35.8 ${\times}$ 20.5 mm(1${\times}$w) for Baegok jam.w) for Baegok jam.

• Journal of Sericultural and Entomological Science
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• v.32 no.1
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• pp.17-30
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• 1990

A 6${\times}$4 top-cross set was made from the ten silkworm parental lines selected by the first principal component scores. They were also analysed for the relationship between the combining ability and the first principal component score. The highest general combining ability effects were detected in the parental lines of Japanese, N39 and chinese, C46, for the most quantitative characters in the study. The first principal component score of factors related to silk productivity in the parents was significantly and positively correlated to the general combining ability of the twelve characters such as cocoon yield, cocoon weight, cocoon shell weight, cocoon shell percentage, duration of the 5th instar larvae, total larval period, length of a bave, weight of a have, non-breaking length of a bave, non-breaking weight of a have, raw silk percentage, and neatness. Similarity distance (D$^2$) was related to the specific combining ability of the characters such as cocoon yield, non-breaking length of a bave, non-breaking weight of a have, non-breaking ratio of a bave, raw silk percentage, neatness. From the results, it is possible to predict the general combining ability effects by the principal component scores for the 12 characters of the parents related to silk productivity.

• Journal of Sericultural and Entomological Science
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• v.29 no.2
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• pp.31-37
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• 1987

Mulberry leaf sprayed on at the various concentrations of cadmium (Cd) was fed on the just molted fifth instar through the 6th day of the fifth instar and content of cadmium and zinc in the feces, organs and tissues involved were analyzed by spectrophotometer. Along with the effect of those heavy metals on development of the relevant organs and tissues sexwise. 1. The residual content of cadmium on mulberry leaf was about 50% of the total cadmium and the weight of feces disposed from the cadmium fed larvae was less than the control. There was distinctive differences in female-wise disposal of feces between cadmium treatment and control ; cadmium treatment female larvae disposed less feces than female of control. 2. Fourteen percent of the total dry weight of the anterior plus the middle silkgland and of the posterior silkgland in cadmium 100ppm treatment was decreased in female but only 9% of the anterior plus middle silkgland in male was made, showing no decrease the weight of the posterior silkgland in male. 3. Decrease of the dry weight of the silkgland, fat body and hindgut was made in cadmium 100ppm treatment and contrarily the weight of midgut and malphihian tube were increased. The total larval weight of the female and male were decreasd in cadmium 100ppm treatment and the decreasing ratio was higher in famale. 4. There wasa no detection of cadmium in all of the organs and tissues of the control and in those of the cadmium treatment the high residual content was in order of the midgut, hindgut, malphighian tube and head. A slight accumulation of cadmium was shown in fat body and silkgland. 5. Cadmium accumulation in the midgut was higher than in female but in the fat body, malphighian tube, trachea and integument was contrarily high in the female than male. 6. The total zinc content of the larvae was below 60ppm in the control and 80ppm in cadmium 100ppm treantment. The increase of zinc content in cadmium treatment was made on silkgland, malphigian tube and midgut but contrarily the decrease of zinc content in fat body was resulted. 7. In cadmium treatment, much more cadmium accumulation took place in the female and zinc accumulation was made much more in the male.

• Journal of Sericultural and Entomological Science
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• v.25 no.1
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• pp.1-20
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• 1983

It has been known that the insect molting hormone and its analogues exist also in plant kingdom and their concentration has been found to be about 0.1~2.0% of dry matter, which is equivalent to $10^3{\sim}10^5$ times of those in insects. This study was carried out; 1) to isolate the phytoecdysones from Korean Achyranthes radix and characterize their physico-chemical properties. 2) to investigate the biological activity of this phytoecdysone on Bombyx mori larvae. The resuls were summarized as follows; 1. The extraction method of phytoecdysones was optimized by three consecutive reflux for 1hr using 200g of dried and milled radix per 1l methanol. 2. The purification from the crude extract was made by a series of steps such as precipitation of gum-type polymer with n-Butyl acetate, adsorption on technical grade silica and chromatography with neutral alumina. The conditions of each step were optimized and the resulting crude crystal was about 500mg per kg dry radix. 3. The crude crystal from the cultivated Achyranthes(Achyranthes japonia) contained ecdysterone (20-hydroxyecdysone) and inokosterone in the proportion of one to one. In order to separate these, a series of processes such as acetylation, separation by alumina column chromatography deacetylation by alcoholysis, deionization and crystallization were introduced and optimized 125mg of ecdysterone and 18mg of inokosterone per kg dry radix were thus obtained. 4. The wild Achyranthes (Achyranthes obtusifolia) radix was found to contain the ecdysterone only. A 285mg of ecdysterone was crystallized per kg dry radix. 5. Isolated ecdysterone, inodosterone and acetylated compounds were characterized by IR., UV., NMR spectroscopy, mp, TLC and densitometry. 6. Ligation experiment was undertaken to confirm the biological activity of the purified ecdysterone; the ecdysterone could induce larval-pupal metamorphosis in the ligated abdomen of 4th instar larvae injecting 0.5~1.0${\mu}g$. 7. By ecdysterone feeding experiment using artificial diet, it was elucidated that the critical time of feeding would be the first half of each instar resulting in increased weight of silk layer. 8. The ecdysterone was fed to 5th instar silkworm at the level of 1, 2, 3, 5ppm of dry feed of artificial diet containing 5% mulberry leaves for 72hrs. At 2ppm of the concentration. body weight and silk layer weight were arrived at maximum. But at higher concentrations body weight and silk layer weight decreased than the control group. At 2ppm of the concentration, body weight was increased by 12.5%. 9. Feeding 2ppm of ecdysterone at the later half of 5th instar, the duration of larvae was shortened.

• Journal of Sericultural and Entomological Science
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• v.23 no.2
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• pp.11-36
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• 1982

Forty-nine plant species as additives to silkworm artificial diet and 5 species as cellulose sources for artificial diet were screened for their economic values as feed-resources for the silkworm. Feeding response to artificial diet was tested on 82 silkworm strains. The effect of rearing conditions on feeding response and enzyme activities in the silkworm was investigated. The results were summarized as follows. 1. Seven species out of 49, Vigna sinensis ENDL, Ipomoea vatatas Lamarck, Cyperus anuricus Var. Laxus, Alnus japonica Stendel, Trifolium repens L, Prunus serrulata Lindley. Var, Glycine max L increased feeding response, compared with the basic formula of artificial diet. 2. The economic values of Vigna sinensis ENDL, Ipomoea vatatas Lamarck, Cyperus anuricus Var. Laxus, Ainus japonica Stendel, Cassia tera L, Erigeron canedensis L as feed-resources for artificiale diet were recognized, through feeding experiment during the entire larval stage. 3. Mulberry cellulose showed the best results in rearing and cocoon characteristics. 4. The extent of feeding response varied according to strains and varieties. Varieties in japanese strains showed higher feeding response than those in chinese and european varieties, with considerable variations among a varieties in strains. 5. The begining of 4th instar seems to be a proper time to convert from mulberry to artificial diet, or artificial diet to mulberry, however the middle of 3rd instar seems acceptable. 6. The optimum temperature for artificial diet rearing is 30$^{\circ}C$ during the period of 1st-3rd instar and 28$^{\circ}C$ for 4th-5th instar. 7. Electrophoretic isozyme patterns of esterase and acid phosphatase on agarose gel, as affected by strain. rearing temperature and feed-resources, were observed as follow. (1) Isozyme patterns of mid-gut esterase varied, depending on instar. One or two more isozyme bands were observed in the larvae than feed on the mulberry fed for the artificial diet. (2) A strain, chinese-15 with a higher feeding response, had 1∼2 more bands than chinese-60 with a lower feeding response. (3) Five bands of mid-gut esterase in 3rd and 4th instar larvae reared at 28$^{\circ}C$. and 4 for 3rd instar and 6∼7 for 4th instar larvae at 35$^{\circ}C$ were observed. (4) No similar esterase bands could be found among mid-gut, blood and silkgland. There are five esterase bands in the midgut, one in blood and three in silkgland. (5) There was rather small digerence in acid phosphatase types of mid-gut and blood according to varieties and rearing temperature. No active band was shown in silkgland. In midgut, there was one acid phosphatase band at 3rd instar, two at 4th instar and three at 5th instar. In blood, one active band at 3rd or 4th instar and three bands at 5th inster wire detected.

• Journal of Sericultural and Entomological Science
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• v.18 no.2
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• pp.89-93
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• 1976

The physiological saline solution for animals is known as Ringer's solution which is used for keeping the function of cold blooded vertebrate animals. Primaily the saline solution is used for the purpose of perfusion experiment in frogs. Later the saline solution is applied in several kinds of animals including human being with satisfactory results. However, this saline solution was introduced to silkworm and it was found that the result was not as successful as in the case of other animals and human being. Normally, in the case of silkworm, the physiological saline solution is prepared in order to maintain the normal function of separated organs and tissues. To this end, the saline solution is adjusted to contain the certain amount and strength of ions, osmosis pressure and hydrogen concentration. The most of cases, the physiological saline solution should be prepared so that the constituent of the solution be the same with the blood selium and body fluid. The hydrogen concentration in the ion element of the saline solution is adjustable by adding Na$\^$＋/, K$\^$＋/, Ca$\^$＋＋/, Mg$\^$＋＋/ which are followed by adding of buffer solution such as NaHCO$_3$and NaH$_2$PO$_4$. Determination of optimum concentration of cation in the physiological saline solution, and the optimum mixing rate of more than two kinds of cations are based on the movement of dorsal vessel in the silkworm larvae. The optimum concentration of cations in the solution is prepared by adding NaCl solution which is under zero point. However, this solution was further added with the different concentration of KCl and CaCl$_2$. By dropping the prepared solution on the 5th larvae, the effects of solution was measured. The measurement was done by observation of movement' of dorsal vessel and its time length, and the number of pulses. According to the experiment, it was found that when only NaCl solution was applied, the number of pulses is increased for a moment, and the pulse stopped after one hour or so. When KCl solution was added the time of pulse was prolonged and in the contrast, the number of pulses was slow down. If KCl and CaCl$_2$solutions are added the time of pulse was further prolonged. Even though the adding of KCl and CaCl$_2$are found to be effectible, the correlation between the concentration of solution and the movement of dorsal vessel was not observed. However, it was same in the case of adding Ca$\^$＋＋/ or K$\^$＋/. It was found that when Mg$\^$＋＋/ was added to dorsal vessel the number of the pulses was not decreased although the prolonged time pulse was observed.

• Journal of Sericultural and Entomological Science
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• v.47 no.1
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• pp.12-17
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• 2005

To develop technique for the production of P. tenuipes stromata on a large scale, the infection of P. tenuipes and the growth of stroma were investigated by silkworm (Bombyx mori) variety. Also, studied about biological activites of fruiting body formed on silkworm. Infection rate of the 5th instar larvae of the silkworm with P. tenuipes was the highest in Yangwonjam, followed by Hachojam, Baegokjam and Chilbojam in that order. Also, as the inoculation times was increased, infection rate tended to be raised. The rate of fruiting body formation of the silkworm pupae infected with P. tenuipes was the highest in Baegokjam, followed by Yangwonjam and Chilbojam in the order. But, actually the fruiting body formation of the 5th instar larvae of the silkworm tested was good in Chilbojam, followed by Yangwonjam and Baegokjam in that order in 3 times spraying inoculation. The fruiting bodies of Yangwonjam and Chilbojam infected with P. tenuipes had high amount of Mannitol, but Baegokjam and Hachojam had high concentration of Glucose on a dry weight basis. The mean content of total amino acid in the fruiting bodies of P. tenuipes was 1.03 ${\mu}mole/g$. The distribution rate of amino acid components decreased in the order of Arginine (12.2%)>Glycine (10.5%)> Proline (9.6)>Tyrosine (8.9%)>Serine>Leucine>Threonine. The most abundant amino acid in the fruiting bodies of the Baegokjam, Chilbojam and Hachojam infected with P. tenuipes was arginine, while Yangwonjam was Glycine. The most abundant fatty acid in P.tenuipes was Oleic acid on a dry weight basis. The unsaturated fatty acids such as Oleic acid, Linoleic acid and Linolenic acid accounted for more than 78% of the total fatty acids.

• Journal of Sericultural and Entomological Science
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• v.26 no.1
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• pp.25-29
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• 1984

Since 1966, practical use of active heavy analogs of the hormones has been also worked out as an insecticide and brought the features of it to the light as cocoon producer. On the other hand, it is expected to afford the increase of silk productivity resulted from control of the fifth larval period by delaying normal development. With these regards, some of analogs have been tried to apply practically to the silkworm for an increase of cocoon productivity. One of the synthesized juvenile hormone available is "Manina". And it is presently used for the increase of silk productivity in Korea. For the practical use, it is very essential the varietal differences in the increase of silk productivity by topical application was tested and the obtained results are summarized as follows. 1. It was evident that the fifty larval period was extended by topical application after 48 hrs. of the last ecdysis, ranging from 8 hrs. to one day, as compared to the control. 2. In pupal rates, there is no significance between control and treatments. It proved that there was no toxicity to silkworm by topical application in general, except jam 120. With regards to an increase of cocoon yield in Japanese, it was resulted from 17∼24% of cocoon yield from 10,000 larvae, as compared to that of control. In case of Chinese, the incrasing rates were varied from 15∼26% of cocoon yield, 17.8kg of it with 26% increase for Jam 122 and 16.7kg of it with 25% increase for Jam 118. In case of all hybrids, an increase of the cocoon yield took places from 20% to 31% and the weight of cocoon layer for the Japanese increased by 6 to 14%, those for the Chinese by 4 to 7% and those for the hybrids ranged from 21 to 29% increase. 3. It was recognized that the hybrid vigor rate took places with the hybrids between high responsing parents to juvenile hormones.