• 한국잠사곤충학회지
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• 제37권1호
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• pp.57-61
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• 1995

토양에 존재하고 있는 새롭고, 특이한 활성을 갖는 B.t를 분리하기 위하여 춘잠 및 추잠기에 양잠농가의 토양을 채취하여 B.t의 분포를 조사하였다. 총 300개의 채취된 토양시료중에서 포자와 내독소 단백질을 생산하는 82개의 B.t를 분리했다. 분리된 B.t의 독성별 분석에서 봄에는 주로 나비목(Bombyx mori)에 독성을 띄는 균주(67%)가, 가을에는 나비목과 파리목(Culex pipiens)에 동시에 독성을 띄는 균주(67%)가 많이 분리되었다. 한편 딱정벌레목(Sitophilus oryzae)에 독성을 나타내는 것은 찾지 못했다. 또한, 내독소 단백질은 생산하지만, 독성을 띄지 않는 균주들도 봄에는 6%, 가을에는 27%의 비율로 분리되어 자연상태에서 흔히 존재함을 알 수 있었다.

• International Journal of Industrial Entomology and Biomaterials
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• 제8권2호
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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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• 제9권1호
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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.

• International Journal of Industrial Entomology and Biomaterials
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• 제18권2호
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• pp.83-89
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• 2009

Multiplication and spore production of three microsporidia(Nosema bombycis, Nosema sp. 1 and Nosema sp. 2) in selected tissues of pupa and adult of silkworm, Bombyx mori L. were studied in two seasons (SI, SII) with distinct temperature (SI: $20.1{\pm}0.8^{\circ}C$ and SII: $25.1{\pm}0.7^{\circ}C$) regimes. Multiplication of the microsporidia followed a logistic pattern with a lag phase, an exponential phase and a stationary phase. In SII, spore production was significantly (P<0.01) higher in various tissues. Highest spore production was observed 30 days post inoculation (p.i.) in SI and in SII, it was $21{\sim}23$ days p.i. Spore production was significantly (P<0.01) higher in the gut tissues than other tissues. Nosema sp. 2 registered significantly (P<0.01) higher spore production in both the seasons compared to Nosema bombycis and Nosema sp. 1. Results indicate that the multiplication and spore production of microsporidia are tissue specific and extremely sensitive to the temperature at which the host is reared. Through this study, the precise day that the spore numbers of the microsporidia are maximized can be predicted in both pupa and adult in case the infection is initiated in the first instar.

• BMB Reports
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• 제45권11호
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• pp.665-670
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• 2012

The insect midgut epithelium is generally lined with a unique chitin and protein structure, the peritrophic membrane (PM), which facilitates food digestion and protects the gut epithelium. We used gel electrophoresis and mass spectrometry to identify the extracted proteins from the silkworm PM to obtain an in-depth understanding of the biological function of the silkworm PM components. A total of 305 proteins, with molecular weights ranging from 8.02 kDa to 788.52 kDa and the isoelectric points ranging from 3.39 to 12.91, were successfully identified. We also found several major classes of PM proteins, i.e. PM chitin-binding protein, invertebrate intestinal mucin, and chitin deacetylase. The protein profile provides a basis for further study of the physiological events in the PM of Bombyx mori.

• International Journal of Industrial Entomology and Biomaterials
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• 제6권2호
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• pp.183-190
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• 2003

An attempt was made to identify superior bivoltine silkworm hybrid suitable for monsoon and spring season of Uttar Pradesh. Breeds with superior cocoon characters and their more popularity in an area were major parameters on basis of which breeds from different regions were selected. Six bivoltine hybrids of silkworm (Bombyx mori L.) of different geographical regions were reared in monsoon (three hybrids) and spring season (three hybrids) during 2000-2002 i.e., for three years at Babasaheb Bhimrao Ambedkar University, Lucknow. Their performances were analyzed statistically for nine characters. The analysis made on a number of traits viz., hatching percentage, larval duration, pupation rate, yield /10000 larvae (by no.), yield /10000 larvae (by weight), cocoon weight, cocoon shell weight, cocoon shell ratio, showed the superiority of one bivoltine hybrid out of the three bivoltine hybrids studied in each season. $SH6{\times}{NB_4}{D_2}$ was found to be superior in major cocoon parameters in both the seasons i.e., monsoon and spring season of Uttar Pradesh.

• International Journal of Industrial Entomology and Biomaterials
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• 제6권2호
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• pp.197-202
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• 2003

The hot climatic conditions prevailing particularly in summer are not conducive to rear these high yielding bivoltine hybrids throughout the year, In order to select efficiently the breeds with high temperature tolerance, it is very important to analyze critically the impact of high temperature on many silk yielding attributes of silkworm races. Keeping the above in view, the present study was undertaken to determine the effect of high temperature $(36 {\pm} 1^{\circ}C)$ and high humidity $(80 {\pm} 5% Relative Humidity)$ on the rearing performance of pure races, foundation crosses, single hybrids and double hybrids of bivoltine silkworm, Bombyx mori L. The robust bivoltine breeds, CSR18, CSR19, 8HT and 5HT, eight foundation crosses, eight single hybrids and eight double hybrids involving these breeds were chosen as materials in this study.

• International Journal of Industrial Entomology and Biomaterials
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• 제31권2호
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• pp.95-102
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• 2015

Insects are heterotherms that exhibit a close relationship between their ecology (especially temperature changes) and physiology. In the present study, selected genes associated with cell death and temperature were examined to determine gene expression in Bombyx mori in high and low temperature environments. We determined the amount of dsRNA, different concentrations of dsRNA, and different type of cells to set the conditions most efficient for RNAi. We then prepared dsRNA transcripts of the genes associated with cell death and temperature response. We analyzed cell damage via Trypan blue staining and found that cell viability was reduced after knockdown of these genes. The special transduced cell lines produced in the present study can be applied in various research fields. We also expect that these cell lines can be used as a research tool for the precise functional analysis of various genes.

• International Journal of Industrial Entomology and Biomaterials
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• 제14권1호
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• pp.63-68
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• 2007

The response of silkworm, Bombyx mori L. to phytoecdysteroid (PE) when administered at different ages of $5^{th}$ instar was studied in the popular bivoltine ($CSR2{\times}CSR4$) and multi${\times}$bivoltine ($PM{\times}CSR2$) silkworm hybrids, reared on the Victory-1 variety of mulberry leaves. PE was administered to $5^{th}$ instar silkworm per os at a rate of $250{\mu}g$ per 100 larvae to different batches of silkworm at 0, 24, 48, 72, 96, 120, 144 hrs and at the onset of cocoon spinning when a few larvae were ripe. The larval and mounting duration, cocoon yield and cocoon characters were influenced by PE. The intensity of influence was dependent on the time of application. The larvae treated at the beginning of the instar, improved the economic traits significantly with a marginal increase in larval duration. In the larvae treated at the middle of the instar, larval duration was shortened remarkably but the economic traits were adversely affected. This particular treatment can become a good management strategy in the case of mulberry leaf shortage or disease incidence. In the larvae treated at the onset of cocoon spinning, the mounting duration was substantially reduced without much effect on the cocoon traits which would be a big benefit in commercial sericulture. The physiological significance of varied response of silkworm to PE administration is discussed.

• International Journal of Industrial Entomology and Biomaterials
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• 제17권1호
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• pp.121-124
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• 2008

The caspase family proteins play an important role in programmed cell death (apoptosis). To date, the expression profiles of the caspase family genes in Bombyx mori (Bm) are poorly known. In this study, we examined the expression profiles of two novel Bm caspase family genes (ice-2 and ice-5), the potential change of the mitochondrial membrane and the morphology in Bm cells after stimulation of ultraviolet (UV) irradiation. The results showed the potential change of the mitochondrial membrane occurred at 5 hours after UV irradiation treatment. Analysis of fluorescent quantitative RT-PCR demonstrated that both the ice-2 and ice-5 might be involved in UV induced apoptosis in Bm cells. Notably, after UV irradiating, expression pattern of ice-2 and ice-5 were remarkably different. The ice-2 gene was highly expressed at two time points, 0.5 and 5 hours after UV stimulating, while the expression level of ice-5 only peaked at 5 hours after UV stimulating. It indicated that apoptosis induced by UV irradiation was involved in the mitochondrial pathway and the two isoforms of Bm ice may act but play different role during the apoptosis of Bm cells.