• Proceedings of the Korean Society of Sericultural Science Conference
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• 2003.04a
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• pp.42-42
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• 2003

The wild silkworm, Bombyx mandarina, was believed the only ancestor of B. mori, inhabits the limited area of Eastern Asia including China, Korea and Japan. However, the geographic dimorphism of B. mandarina was reported with chromosome number and arylphorin gene. In connection with those dimorphism, we studied the genetic differences of ITS-2 region in rDNA purposing the differentiation and geographic variation within the species of B. mandarina. (omitted)

• International Journal of Industrial Entomology and Biomaterials
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• v.47 no.1
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• pp.1-11
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• 2023

The Indian golden muga silkworm, Antheraea assamensis Helfer is an economically important wild silkworm endemic to Northeastern part of India. In recent years, climate change has posed a threat to muga silk production due to the requirement that larvae be reared outdoors. Since the muga silkworm larvae are exposed to the vagaries of nature, the changing climate has increased the incidence of microbial diseases in the rearing fields. Accurate diagnosis of the disease causing pathogens and its associated epidemiology are prerequisites to manage the diseases in the rearing field. Although conventional microbial culturing methods are widely used to identify pathogenic bacteria, they would not provide meaningful information on a wide variety of silkworm pathogens. The information on use of molecular diagnostic tools in detection of microbial pathogens of wild silk moths is very limited. A wide range of molecular and immunodiagnostic techniques including denaturing gradient gel electrophoresis (DGGE), random amplified polymorphism (RAPD), 16S rRNA/ITSA gene sequencing, multiplex polymerase chain reaction (M-PCR), fluorescence in situ hybridization (FISH), immunofluorescence, and repetitive-element PCR (Rep-PCR), have been used for detecting and characterizing the pathogens of insects with economic significance. Nevertheless, the application of these molecular tools for detecting and typing entomopathogens in surveillance studies of muga silkworm rearing is very limited. Here, we discuss the possible application of these molecular techniques, their advantages and major limitations. These methods show promise in better management of diseases in muga ecosystem.

• International Journal of Industrial Entomology and Biomaterials
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• v.1 no.1
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• pp.9-17
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• 2000

Genetic variation in the domestic silkworm strains (Bombyx mori) and phylogenetic relationships between domestic silkworms and wild silkworms (B. mandarina) were investigated by using a portion of mitochondrial CGI gene sequences. Ten geographic strains of B. mori we sequenced were identical in the 410 bp-section of mitochondrial COI gene. This sequence was also identical to the homologous sequence of the four Gen-Bank-registered strains, but one strain of B. mori differed a single nucleotide (0.2%) from others. MtDNA homogeneity in the B. mori strains appears to be resulted from fixation into the mast frequent mtDNA type during the course of breeding for new strains, in which an extensive indoor rearing and removal of unwanted individuals were accompanied. In the comparisons between domestic and wild silkworms, some wild silkworms were closely related to domestic silkworms (0.2%-1.2% of divergence), but the others were not (2.7%-3.7% of sequence divergence). This result was also reflected in the phylogenetic analyses, showing two independent phylogenetic groups: one including all B. mandarina sequences and the other including both B. mandarina and B. mori sequences. Thus, domestic silkworms may have been derived from the ancestor of B. mandarina, which belongs to this group, alto-ough more extensive study will provide better understanding on this issue.

• Korean journal of applied entomology
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• v.31 no.1
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• pp.33-36
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• 1992

To establish the succeeding generations of wild silkworms, Bombyx mandarina Moore, massrearing was made in the laboratory. The rearing result was good under high humidity and moderately warm condition. Larval periods were 15 to 25 days and the most of larval period was around 17 days. The pupation rate and the pupal period of most of males and females were 40% and 13 to 25 days, respectively. There were two emergence peaks of males and females, and males emergence peak occurred two or three days faster than females.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.2
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• pp.87-90
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• 1998

Hemolymph is oxidized and darkens visibly during the collection from silkworm due to the activity of tyrosinase in it. Toxic quinones are produced by the oxidation and consequently inhibit the cell growth. Heat treatment can be used to prevent the oxidation ; however, the oxidation may occur during the collection of hemolymph before it is heat-treated. It makes the hemolymph collection difficult especially on a large-scale preparation. Hemolymphs collected from 257 different strains of silkworms were examined to select the slowly oxidized hemolymphs. Hemolymphs collected from mutant strains such as Lemone, TBO, Cre, Y4, and wEb showed relatively slow color changes. Oxidation rates of the hemolymphs were measured by the absorbance change using a spectrophotometer. The hemolymph of wEb showed the slowest oxidation. The absorbance of this mutant hemolymph reached the saturation value at 20$^{\circ}C$ in 450 min, whereas the total oxidation time of the wild-type (Baekokjam) hemolymph at the same temperature was 120 min. We tested if this mutant hemolymph is useful as a medium supplement for insect cell culture. Cell growth rate and final cell concentration in the medium supplemented with the wEb hemolymph were almost same as those in the medium supplemented with the wild-type hemolymph. Hemolymph is collected on a small scale by clipping the abdominal leg; however, this method is not appropriate fro large scale preparation. Centrifugation after chopping the silkworm hemolymph by a blending mixer is a more appropriate procedure for large scale collection. Slowly oxidized wEb hemolymph resulted in higher cell concentration than the wild-type hemolymph when hemolymph was collected by the large scale preparation method.

• Journal of Sericultural and Entomological Science
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• v.37 no.1
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• pp.16-26
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• 1995

DNA restriction fragment length polymorphisms(RFLPs) were used for the classification of 22 leading silkworm races and wild silkworm, Bombyx mandarina. A genomic DNA library from silkworm was partially constructed and was prescreened to evaluate the selected DNA probes. Three DNA probes (SP1-13, SP1-28, 10-42) were selected to determine the polymorphism between silkworm races. As a result, high polymorphism with the probe SP1-28, moderate polymorphism with SP1-13 and monomorphism with 10-42 were obse-rbed.

• Journal of Sericultural and Entomological Science
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• v.39 no.1
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• pp.22-29
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• 1997

Ultraviolet weavelength (UV) of 366 nm produced clearer fluorescent dolor than that of 254 nm for the inspection of silkworm cocoons. Fluorescent color of silkworm cocoons varied in color, appears no relationship with the natural color under the normal light. Uniformity of fluorescent color was improved by selection of blue or yellow line from wild types. Blue and yellow, located at the opposite poles on the color solid and L*a*b* color system, confirmed as pure standard of fluorescent color in the silkworm races for commercial white cocoons. the cocoons with blue fluorescence occupied as high as 1.7 to 8.6 times than those with yellow in the Japanese silkworm races. Fluorescence of silkworm cocoon was not affected by forced flow dry at 70$^{\circ}C$ for 6 hrs. While the Japanese races revealed no sexual difference in fluorescent color, sex-dependence of the color was common in the Chinese races for commercial white cocoon. The fluorescence of cocoon shell of Chinese races showed clear separation of blue of median color. Silkworm strain of Dc20 and Fc24 were sexualy segregated 98.8${\pm}$1.20%, 99.0${\pm}$1.00% by cocoon fluorescence, as that of 99.3${\pm}$0.44% by typical larval marking of sex-limited inheritance. Specific expression of cocoon fluorescence, applicable to breeding of simple discrimination of sex for Chinese races, inspected thoroughly on the surface and inner layer of cocoon shell.

• Journal of Life Science
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• v.8 no.4
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• pp.426-430
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• 1998

The molecular relationships have analyzed between the Bombyx mandarina(wild silkworm) and Bombyx mori strains (domesticated silkworm, geographical silkworms). A total of 166 polymorphic RAPD markers amplified from 35 different primers were used to analyze the molecular relationships among thirteen silkworm strains. The genetic similarity coefficient between Bombyx mandarina and Jam305 showed the lowest genetic similarity value with 0.451, Bombyx mandarina and Bibaekjam showed the highest genetic similarity value with 0.958. These strains were classified into Bombyx mandarina(a wild silkworm) and Bombyx mori(twelve domesticated silkworm) groups upon the genetic similary coefficient of 0.55. Further classificient of 0.60; the 1st sub-group (J111, Bibaekjam, $pnd^{ps}$), the 2nd sub-group (Galwon, C18, od yujam, JAM306, C108), the 3rd sub-group(R-hwang, p50), the 4th sub-group(zebra) and the 5th sub-group(JAM305). According to this study, RAPD markers seems to be a valuable tool for molecular relationships and classification among the silkworms.

• International Journal of Industrial Entomology and Biomaterials
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• v.31 no.2
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• pp.127-131
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• 2015

Oak silkworm, Antheraea yamamai (A. yamamai), has been used for clothing and surgical suture and considered as biomaterial due to RGD tripeptide. This paper reported the degumming conditions of A. yamamai using sodium oleate, high pressure and temperature, and sodium carbonate. Degumming ratio of A. yamamai cocoon using sodium oleate was less than 10%. High pressure and temperature treatment induced 30% weight loss of A. yamamai cocoon. The concentration, treatment temperature and time using sodium carbonate was examined and revealed the following conditions for degumming; 5% owf, 60 min at 100℃. The degummed solution was confirmed using UV and FT-IR spectrometer. Our results can be used to handle A. yamamai silkworm cocoon for further application including material processing.

• International Journal of Industrial Entomology and Biomaterials
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• v.26 no.2
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• pp.67-73
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• 2013

Antheraea mylitta Drury is basically a crossbreeding species, as such it seems to be potentially a good material for the exploitation of heterosis. In the present study F1 hybrid of wild ecorace Laria (L) and semi-domestic Daba (D) was raised and evaluated for various quantitative traits and biochemical parameters during larval stage. Improved fecundity ($+18{\pm}1.8%$ and higher egg hatching rate ($+10.96{\pm}1.3%$) was recorded in the F1hybrid ($L{\times}D$). Biochemical parameters studied in the hemolymph, midgut and fatbody of the larva showed significantly higher (P<0.05) total proteins and carbohydrate concentration besides digestive enzyme activity. Correspondingly SDS-PAGE revealed more number of protein bands in the hemolymph sample of F1s, ranging between 29 kDa to 66 kDa compared to parental lines. The present study demonstrates the positive heterosis effect in the F1 hybrid of Laria ${\times}$ Daba. Biochemical analysis indicates that, there is possibilities of exploitation of hybrids with specific parents targeted for desirable commercial traits (silk yield and fecundity). Moreover, most of these biochemical parameters can be used as markers to analyze the genetic improvement in the tasar silkworms.