• International Journal of Industrial Entomology and Biomaterials
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• v.6 no.1
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• pp.27-31
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• 2003

Infectious flacherie of silkworm Bombyx mori is caused by B. mori infectious flacherie virus (BmIFV) and causes severe crop loss to sericulturists. In the present study, a colloidal textile dye-based dipstick immunoassay is developed for the detection of infectious flacherie in silkworms. Colloidal textile dye (blue D2R) with Aλ$_{max}$ at 620 nm was sensitised with 500 $\mu\textrm{g}$/ml of purified anti-BmIFV IgG. The dye-antibody reagent detects purified antigen up to 10 ng/ml and BmIFV infection in diseased larval extracts $(up to a dilution of {10^-5})$ and faecal matter extracts $(up to a dilution of {10^-2})$ by forming clear blue dot within 30 min. It was observed to be stable for three months period at $4^{\circ}C$. The efficacy of textile dye-based dipstick immunoassay was on pay with HRP-based dipstick immunoassay and fluorescent antibody test, and better than latex agglutination and ouchterlony tests in the detection of BmIFV The dye-based dipstick immunoassay method provides a simple, sensitive and less expensive test for the detection of BmIFV infection in silkworms.s.

• International Journal of Industrial Entomology and Biomaterials
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• v.6 no.1
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• pp.99-102
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• 2003

A cDNA of novel immulectin homologue (BmIML), a C-type lectin, was cloned from the silkworm, Bombyx mori. The immulectin cDNA is an open reading frame of 921 bp encoding 307 amino acid residues. The deduced amino acid sequence from the BmIML cDNA contains two C-type carbohydrate recognition domains (CRDs). The BmIML was most similar (61 % protein sequence identity) to the M. sexta immulectin-1, whereas BmIML showed relatively lower identity to the B. mori lipopolysaccharide-binding protein (25% protein sequence identity). These features of BmIML indicate that BmIML is a novel member of C-type lectin superfamily. Northern blot analysis revealed that the BmIML is specifically expressed in the fat body of B. moli larvae.

• International Journal of Industrial Entomology and Biomaterials
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• v.2 no.1
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• pp.61-64
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• 2001

Ubiquitin can be covalently attached to cellular proteins as a post-translational modification rind is involved in metabolic stresses, such as bent shock and immune response. We have isolated and sequenced a cDNA encoding ubiquitin from the silkworm, Bombyx mori. The insert in the clone is 533 nucleotide long with an open reading frame of 387 nucleotides that encodes a protein of 129 amino acids with a molecular weight of 14.8 kDa. The amino acid sequence shared high homology with the ubiquitins known so far, The result of dot blot hybridization showed that the B. mori ubiquitin gene is up-regulated upon f. rofi infection, suggesting that the B. mori ubiquitin plays an immune-related role.

• International Journal of Industrial Entomology and Biomaterials
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• v.11 no.2
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• pp.139-143
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• 2005

The implications of temperature (25, 30 and $35^{\circ}C$) and relative humidity (RH; 60, 70 and $80\%$) on the hatching rhythmicity and hatching parameters (percentage and duration) were studied in the silkworm, Bombyx mori L. under natural photoperiod (LD 12 : 12). Disease free layings (DFLs) of two pure silkworm breeds, Pure Mysore (PM, a multivoltine breed) and $NB_4D_2$ (a bivoltine breed), and their hybrid, $PM{\times}NB_4D_2$ were introduced into the experimental conditions on the $3^{rd}$ day of oviposition till completion of hatching. The hatching rhythm was predominantly diurnal under all temperature and humidity conditions, with peaks just after 'lights-on' phase (6 hrs). Extreme temperature and humidity conditions did not alter the hatching rhythmicity, but prolonged the hatching durations, extending it to the next day, coupled with reduced hatching percentage in PM and $PM{\times}NB_4D_2{\cdot}In\;NB_4D_2$, on the other hand, hatching did not extend to the next day. Hatching percentage in this breed, however, reduced below the economic level under high temperature and low humidity conditions. The high temperature and low humidity together, though did not alter the rhythmicity, seems to exert synergetic effect on the hatching percentage and its duration in the silkworm, B. mori.

• International Journal of Industrial Entomology and Biomaterials
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• v.11 no.2
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• pp.107-111
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• 2005

Impact of microsporidian infection and season on reproductive potential of Bombyx mori L. was investigated in the laboratory. Microsporidian infection significantly (P<0.01) reduced fecundity and hatching and increased sterility and mortality of eggs. Among the microsporidia, Nosema sp. 2 infected silkworm produced eggs with least fecundity and hatching percent as well as highest dead and sterile eggs followed by Nosema sp. 1 and N. bombycis. Microsporidia, in general, significantly reduced fecundity and hatching percent of eggs and increased number of dead and sterile eggs in all the three seasons except N. bombycis in July - August (S3) and Nosema sp. 2 in January February (S1). Since, seed production is the anchor sheet of mulberry sericulture, coefficient of egg lying is considered as an important aspect and the industry quite often facing shortage of disease free layings. The present study indicates that B. mori is more susceptible to microsporidia during S2 followed by S3 and S1 and Nosema sp2. is most virulent followed by Nosema spl. and N. bombycis.

• International Journal of Industrial Entomology and Biomaterials
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• v.9 no.1
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• pp.145-148
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• 2004

As an initial step to define the molecular mechanism of diapause during embryogenesis of the silkworm, Bombyx mori, mRNA transcripts from diapausing eggs and diapause-activated eggs were compared by differential expression using cDNA microarray. Twenty-four individual cDNA clones were identified. Amomg them, ten genes including alcohol dehydrogenase, dead box-l, cytochrome oxidase subunit I and 18 wheeler showed increased expression in the diapause-activated eggs. The rest of fourteen genes showed increased expression in diapausing eggs.

• Journal of Sericultural and Entomological Science
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• v.37 no.1
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• pp.57-61
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• 1995

In order to isolate naturally occuring novel B. thuringensis strains, we identified the distribution of B. thuringiensis from soils of sericultural farms(spring and autumn season, respectively) of various regions in Korea. A total of 82 strains of B. thuringiensis producing spore and crystal were isolated. We examined oral toxicity against lepidopterous larvae, Bombyx mori, dipterous larvae, Culex pipiens and coleopterous, Sitophilus oryzae. The results showed that 82 B. thuringiensis isolates from sericultural farms were isolated and most isolates were toxic to lepidopterous larvae. Particularly, B. thuringiensis strains which is lepidopterous-active, lepidopterous-and dipterous-active were widely distributed. Also, non-toxic B. thuringiensis isolate was common.

• International Journal of Industrial Entomology and Biomaterials
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• v.6 no.1
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• pp.93-97
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• 2003

We describe here the cloning of a cDNA encoding putative calreticulin (CRT) from the silkworm, Bombyx mori. The CRT cDNA comprised of 1,194 bp encoding 398 amino acid residues. B. mori. CRT has a HDEL sequence at the end of the C-domain. The B. morl, CRT showed 88% protein sequence identity to the G. mellonella CRT, 71 % to A. aegypti CRT, and 63% to H. sapiens CRT, Phylogenetic analysis revealed that the deduced amino acid sequences of the B. mori CRT formed a highly inclusive subgroup with other insect CRTs. Northern blot analysis exhibited an expression of the B. mori CRT gene in the fat body, evidencing the fat body as a major site for CRT synthesis.

• International Journal of Industrial Entomology and Biomaterials
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• v.8 no.2
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• pp.123-127
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• 2004

Normally, silkworms, Bombyx mori, generate offspring by sexual activity. As we known, the hybrids of the first generation of the silkworm have higher cocoon production than pure lines. During the sericulture production, many processes are related with sex control. For example, sex sorting in the egg grainages, rearing of only male silkworm to save the mulberry leaf consumption and increase silk output and quality. Therefore it is very interested in understanding the sex control of the silkworm in theory and practice. Chinese sericultural scientists have been being engaged in the researches in the fields of artificifial parthogenesis, dispermic androgenesis, sex-limited varieties, sex linkage balanced lethal strain and high temperature sensitive male stocks for several decades and gained substantial achievement. Some of the achievements have been used in the commercial production. In this review, the authors introduced that the methods for control of the silkworm sex, and regulate the silkworm sex ratio according to different producing aim in the world and especially in China.

• International Journal of Industrial Entomology and Biomaterials
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• v.9 no.1
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• pp.73-78
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• 2004

The impact of low concentration fluoride on toxification was studied by treating $3^rd$ instar silkworm larvae of Qiufeng${\times}$Baiyu (Fluoride resistant strain) and Jinshong${\times}$Haoyue (Fluoride sensitive strain). The $5^th$ instar silkworm larvae of Zhenong-l, Shu-12, Qiufeng ${\times}$ Baiyu, Chunhua ${\times}$ Qhiushi, Jinshong and Haoyue were fed mulberry leaves treated with sodium fluoride at different concentrations to determine its effect on fecundity. Harmful effects of low concentration fluoride at early instars on growth, development and economic characters of Bombyx mori are related to its resistance. Harmful effect on resistant strain Qiufeng${\times}$Baiyu manifested on prolongation of instar duration of 15 and 6% in 70 ppm, where as the sensitive breed Jinshong${\times}$Haoyue manifested with 100% mortality in 50 ppm. The impact of low concentration fluoride on fecundity resulted in considerable increase in formed eggs (9%) and laid eggs (9%) in Zhenong-l and Shu-12 among treated population over control. The present observations emphasis that fluoride apart from exhibiting harmful effects on silkworm growth and development, however, its low concentration do playa vital role in inducing some positive effect on fecundity and cocoon traits.