• Journal of Sericultural and Entomological Science
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• v.18 no.2
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• pp.83-88
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• 1976

A study was made on the interstrain difference in dose-infection response and induction response of silkworm to the two strains of cytoplasmic polyhedrosis virus to obtain some informations on screening the leading strains. Comparison of dose-infection responses of larvae following the inoculation of the inclusion body of cytoplasmic polyhedrosis virus revealed that there is no significance in the resistance to dose-infection and any of strains were more resistant at advanced stage(4th instar) than younger stage(2nd instar). In the pathogenicity between cytoplasmic polyhedrosis virus with hexagonal and tetragonal outline, the hexagonal polyhedra showed higher pathogenicity than the tetragonal polyhedra. However, the averages of $LC_{50}$ of cytoplasmic polyhedrosis virus with hexagonal outline to larvae of parental inbred line were 6.12${\times}$10$\^$6//$m\ell$ at 2nd instar and 1.57${\times}$10$\^$7//$m\ell$ at 4th instar in spring and those to their hybrids were 1.28${\times}$10$\^$6//$m\ell$ at 2nd ins tar and 4.99${\times}$10$\^$6//$m\ell$ at 4th ins tar in autumn. Meanwhile the $LC_{50}$ averages of tetragonal polyhedra. to larvae of parental inbred line were 2.06${\times}$10$\^$7//$m\ell$ at 2nd instar and 5.67${\times}$10$\^$7//$m\ell$ at 4th instar in spring and those to their hybrids were 9.84${\times}$10$\^$6//$m\ell$ at 2nd instar and 3.86${\times}$10$\^$7//$m\ell$ at 4th instar in autumn, respectively. In comparison of induction response of silkworm larvae to inoculation of tetragonal polyhedra of cytoplasmic polyhedrosis virus, the induction rate of hexagonal polyhedra was remarkably higher in the treatment of inoculation at 2nd instar than at 4th instar and at the concentration of 1.3${\times}$10$\^$6//$m\ell$ than at any others. Most of induction showed a mixed infection with hexagonal and tetragonal polyhedra of cytoplasmic polyhedrosis virus.

• 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.10
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• pp.1-25
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• 1969

Since widely use of anthracite for the radiating purpose in a rearing room in Korea, the weakness of silkworm, poor uniformity of the worm growth, the increase of missing worm ratio, unusual cocoon assorting ratio, and the decrease of cocoon layer ratio have been realized by the author, therefore, he has started out to search the mechanism of these evil influences regarding with various gas densities and terms of the gas treatment which will be supposed to be a warning for temperature control during the silkworm reading work. Among the anthracite gas components, CO or SO$_2$ influence and their complexed harm effect were investigated through the use of anthracite gas, CO and SO$_2$ gas. Meantime, each treatment was applied, separately, during the worm egg stage, young instar, adult instar and whole instar, because the harm intensity for any improperable rearing condition is flexible by the growing stages. Meantime, the gas density and term variation were applied for the above each treatment such as in case of anthracite and CO gas, the following treat methods were used. 1) 0.06% for 30 mins. 2) 0.06% for 1 hour. 3) 0.1% for 1 hour. 4) 0.15% for 1 hour. on the other hand, SO$_2$ gas was used as 1) 120ppm for 30 mins. 2) 200ppm for 30 mins. 3) 400ppm for 30 mins. The measurement of gas density was proceeded by using CO tester (Carbon Monoxide Indicator) and SO$_2$ tester (Indicator Sampler Cgf) which could keep any specific density before each treatment.

• Journal of Sericultural and Entomological Science
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• v.45 no.1
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• pp.10-17
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• 2003

This study was carried out to analyze physicochemical characteristics of sericin cocoon from silkworm, Bombyx mori. The degumming loss increased with increasing treatment time up to 2 hr, and temperature up to 130$^{\circ}C$. At 130$^{\circ}C$, degumming loss of Nd-s jam and Nd$\^$H/ jam were 100% while that of Baegok jam was 24%. Nd-s jam and Baegok jam ha high glycine content of 29.1∼46.3 mol% where as Nd$\^$H/ jam had high serine content of 32.6 mol%. Thermal denaturation temperatures were found at 218$^{\circ}C$ for Nd-s jam, 216$^{\circ}C$ for Nd$\^$H/ jam, and 218$^{\circ}C$ for Baegok jam. Before degumming, crystallinities obtained by FT-IR analysis were 44.3, 43.7, and 59.9% for Nd-s jam, Nd$\^$H/ jam, and Baegok jam respectively. After degumming, crystallinity increased to 61.8% for Baegok jam. Before degumming, crystallinitics obtained from XRD were 35.9, 33.5, and 47.2%, for Nd-s jam, Nd$\^$H/ jam, and Baegok jam. After degumming, crystallinity increased to 49.8% for Baegok jam. The molecular weight of Nd$\^$H/ jam were 9,417 in 1 hr, 3,744 in 2 hr, 4,944 in hr, and 3,910 in 6 hr.

• Journal of Sericultural and Entomological Science
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• v.14 no.1
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• pp.9-13
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• 1972

On the seventh day of mounting male and feamale cocoons are distinguished. A part of those male and female pupae is irradiated for 40 min. with 1,000r-ray irradiation. Those eggs obtained from the irradiated pupae are divided into six groups of 5, 15, 45, 90, 720 and 2,400 minutes after laying. The cahanges of accid soluble phosphorus in the each group of eggs are as follows. 1. In the control group of the maximum quantity in acid soluble phosphorus was 1,456r/100mg D.P. in the 2,400 minutes group, while the minimum quantity was 1,233r/100mg D.P. in the 720 minutes group. 2. In the mated group of ＊irradiated female moths and control male moths, the quantity of acid soluble phoshorus was small as compared with the control group in the five minute group of 1,288r/100mg D.P. and in the 15 minutes group of 1,299r/100mg D.P. while the quantity increased to 1,484r/100mg D.P. in the 45 minutes group. The quantity began to decrease again to 1,400r/100mg D.P. in the 2,400 minutes group which was smaller than that of the control group. The quantity was slightly small in the silkworm eggs laid in the early stage when compared with that of mated group of ＊irradiated male moths and control female moths. Both groups showed the larger quantity in the 720 minutes group than that of the control group. The quantity of acid soluble phosphorus in the mated group of control female moths .and ＊irradiated male moths was larger in variation than in the mated group of control male moths and ＊irradiated female moths. 3. In the mated group of ＊irradiated male and female moths the largerst quantity was 1,760r/100ms D.P. in 2,400 minutes group and second was 1,736r/100mg D.P. in 90 minutes group, and third was 1,288r/100mg D. P., in 5 minutes group. Generally the quantity was small in silkworm eggs laid by the irradiated one in the early stage than the control group, but in the later period of egg the quantity began to increase more than that of control group.

• Journal of Sericultural and Entomological Science
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• v.29 no.2
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• pp.44-50
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• 1987

The silkworms were inoculated with flacherie virus and reserved at high temperature (37$^{\circ}C$) to find out the effect of high temperature on the multiplication of the virus in silkworms. The obtained results are summarized as follows. 1. It was shown that the inhibitory effect of high temperature treatment on the virus multiplication was achieved at high level at the newly molted stages in 5th instar larvae and both in 4th and in 5th larvae. 2. Twelve hours treatment and 24 hours treatment showed high inhibitory effect on the multiplication of flacherie virus. 3. The silkworms were inoculated with flacherie virus at the newly molted stage in 2nd instar larvae and followed by have temperature (37$^{\circ}C$) treatment at the newly molted stages in 5th instar and both in 4th and in 5th instar for 12 and 24 hours respectively. The increase in the survival rate with high temperature treatment ranged from 33.8 to 39.5 percent in index number and cocoon productive was 45.8 to 54.2 percent compared to non-treatment. 5. In the inoculation of the virus to the 4th instar larvae, the high temperature treatment at the newly molted stage in 5th instar brought increases in the survial rate from 49.7 to 68.9 percent in index number and in cocoon production from 44.3 to 69.0 percent.

• 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.

• Current Research on Agriculture and Life Sciences
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• v.20
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• pp.55-63
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• 2002

This experiment was to know properties of Sericin Jam that development, growth of silkgland, content of sericin and composition of amino acid in hemolymph. The characters of Sericin Jam can he seen form this experiment. Hatching ratio was 85% in Sericin Jam and 95% in Jam 120. Especially hatching period of Sericin Jam was longer than Jam 120 and also hatching of Sericin Jam was ununiform. The larval duration of Sericin Jam was 20 days and 23 hours, and Jaw 120 was 21 days and 22 hours. In Sericin Jam, middle silkgland contain a great p arts in silkgalod and posterior silkgand is short and no curves. The period of mounting to emergence was 12 days in Sericin Jam. The period of pupa was 7day. It is property of Sericin Jam that the period is short. Cocoon was very thin and light in Sericin Jam. Weight of cocoon shell of Sericin Jam is 2.7cg. The sericin protein quantity was 100% in cocoon shell of Sericin Jam, about 28% in cocoon shell of Jam 120, however the sericin ratio per Sericin Jam cocoon was 34.6% compare to cocoon shell of Jaw 120 in sericin protein quantity. The amino acids in hemolymph of Sericin Jaw was much hidtidine, lysine, glut amic acid. And the amount of almost amino acids were increased depends upon development at t he 5th instar.

• Journal of Sericultural and Entomological Science
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• v.9
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• pp.67-87
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• 1969

1. Objectives and Importance. Many silkworms have been damaged by nuclear polyhedrosis virus diseases thoughout the country every year causing a decease in cocoon production by approximately ten per cent per year. The damage caused by the infections virus has occured in spite of complete disinfection. In this respect, it is well known it is impossible, at the present time, to protect the silkworm from these virus infections through chemical and physical control methods. Therefore, this author has attempted to solve this urgent problem from the view point of heredity and breeding, discovering the different resistances and heritabilities among 120 stains collected from throughout the country, and selecting the ones with highest resistance for the basic materials in the silkworm breeding. 2. Results of work 1) The strains with strong resistance to the nuclear polyhedrosis virus diseases are N$_4$, N$\sub$15/, N$\sub$48/, C$\sub$55/ and Em. the log ED$\sub$50/ values of them vary between 0.799 and 1.611. The susceptible strains are N$\sub$20/, C$\sub$62/, N$\sub$76/, N$\sub$79/ and C$\sub$108/, the log ED$\sub$50/ values of them vary between 5.159 and 7.258. (Reference Table 4) The Japanese strain with a log ED$\sub$50/, value of 3.770 is the strongest, followed by the Chinese strain with a log ED$\sub$50/ value of 3.564. The weakest is the European strain with a log ED$\sub$50/ value of 3.3381. The direction coefficient of the regression equation of the susceptibility varies between 0.1 and 0.6, the uniformness of the resistance of the preserved strains of this country is comparatively low. The hereditary henomena of the resistance of each strain and the conerete method of its application for silkworm breeding main the subjects for later studies. 2) The content of water and ash in silkworm has not been correlated with the capability for resistance to the virus diseases(Reference. Table 8). but it is very significantly correlated with mortality rate (in common reaning). In the case of the silkworms which have just completed the fourth moulting the content of water and ash is not related to the mortality rate. In the case of the silkworms which have just completed the third moulting, however, the water( +0.326) and ash (+0.362) registered a high significance. The ash content in the first ($\div$0.520) and second ($\div$0.386) moults is highly significant but water content in both cases is not significant (Reference Table 7). 3) The No. 205 strain proved to be the best in character among the various F$_1$ hybrids. No. 204 was very good in strength but a little lower in cocoon character than the control. No. 212 was a little low in coccon character and mortality was average, but the cocoon harvest was the best among all the varieties offered for (Reference Table 9). 4), In short, the above mentioned strains which are known to have strong resistance to the virus disease are expected to provide basic data for breeding strong varieties. It is proposed that continued research should be conducted on the characteristics of various strains for a satisfactory preservation of various characteristics.research should be conducted on the characteristics of various strains for a satisfactory preservation of various characteristics.

• Journal of Sericultural and Entomological Science
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• v.26 no.2
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• pp.11-15
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• 1984

To save the labour reguired for separation of copulated moth during egg Production, some of the chemicals available at the market were on screen test for easy separation of copulated moth of silkworm. The obtained results are summarized as following. 1. In a separation ratio of copulated moth along with a treating time, TCTFE(Trichloro-trifluoroethane) completely separated the copulated moth in 10 minutes. The combinations of TCTFE plus Acetone (87.5 : 12.5 V/V) and TCTFE plus Acetic acid (50 : 50 V/V) take 25minutes for the complete separation of copulated moth. Use of Acetic acid solution only makes 100% separation of copulated moth in one hour and foully minutes and non$.$treatment shows only 47.5% of separation in three and half hours. On the other hand. There is no statistical significance between TCTFE Plus Acetone and control in the egg productivity. 2. The combination of TCTFE Plus Acetone (87.5 : 12.5 V/V) does not infuluence the egg productivity of the moth, showing 443 grains for an average number of egg per moth out of which 417 grains are for the number of fertilized eggs while control shows 452 grains for an avarage number of egg/moth and 428 grains for the number of fertilized eggs. However a sing1e use of TCTFE and Acetic acid shows less egg productivity and number of ferilized eggs per moth, respectively as compared to those of the control. In particular, a single use of acetic acid makes an increase of number of non-egg prodncible moth and it seems to be brought due to a chemical damage. 3. In a rearing test of the egg laid by the chemical treated moth, there are no differences among the treatments in all of the useful characters of the larvae; larval duration, survival rate, cocoon yield, single cocoon weight, single cocoon shell weight and cocoon shell ratio. In these regards, it is recognized that TCTFE can be practically used for the separation of copulated moth and the combination of TCTFE and Acetone promote its efiectiveness on the separation of copulated moth.