著者

Kenji Yukuhiro Kazuya Iwata Natuo Kômoto Shuichiro Tomita Masanobu Itoh Makoto Kiuchi

出版者

The Japanese Society of Sericultural Science

雑誌

Journal of Insect Biotechnology and Sericology (ISSN:13468073)

巻号頁・発行日

vol.81, no.1, pp.1_029-1_035, 2012 (Released:2013-01-28)

参考文献数

21

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We analyzed 3633 Japanese Bombyx mandarina COI sequences from 37 locations in Japan, found 94 segregating sites in 714-bp long COI nucleotide sequences and eventually identified 121 haplotypes. We further confirmed that the 121 haplotypes were different from the 8 B. mori haplotypes reported by Yukuhiro et al. (2011), and the result strongly suggested little gene flow from B. mori to Japanese B. mandarina. We discuss the properties of the mutational differences between the two species.

著者

Haruka Kawaguchi Teruyuki Niimi

出版者

The Japanese Society of Sericultural Science

雑誌

Journal of Insect Biotechnology and Sericology (ISSN:13468073)

巻号頁・発行日

vol.87, no.2, pp.2_035-2_044, 2018 (Released:2018-08-07)

参考文献数

22

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The development of genome editing techniques has allowed the generation of tremendous genetic diversity, even in non-model insects. The major obstacle for maintenance of genetically diverse stocks in non-model insects is the need for constant rearing in the laboratory, which is labor-intensive and time-consuming. The maintenance of insect colonies in the laboratory is further complicated by risk factors such as disease contamination, human error, and genetic changes by natural mutations that can lead to the loss of desirable genotypes. To avoid these risk factors, cryopreservation is the most desirable option. Here, we present a method we developed for cryopreservation of ovary from the multicolored Asian ladybird beetle, Harmonia axyridis, adapted from techniques for ovary cyropresevation in the silkworm, Bombyx mori. We used last (4th) instar beetle larvae as both donors and recipients for the cryopreserved ovaries. The best and average success rates of cryopreservation were 40% and 26%, respectively, based on the percentage of beetles receiving cryopreserved ovary transplants that subsequently laid viable eggs. This success rate is much higher than that reported for B. mori using last instar larvae. The 26% average success rate is sufficient for the technique to be of practical use for maintaining genetically diverse lines of H. axyridis, and reduces the laborious tasks required for constant maintenance of numerous colonies. This is the first reported success in ovary cryopreservation for a small non-model insect. The techniques that we developed should also be useful for ovary cryopreservation in other small non-model insects.

著者

Kiyoshi Asaoka

出版者

(社)日本蚕糸学会

雑誌

Journal of Insect Biotechnology and Sericology (ISSN:13468073)

巻号頁・発行日

vol.72, no.2, pp.117-125, 2003 (Released:2004-10-27)

参考文献数

43

被引用文献数

1

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Ultrastructure of sensilla on the maxilla of the silkworm, Bombyx mori L. was observed by light microscopy and by both scanning and transmission electron microscopy. Structural differences among different silkworm strains, if any, were also examined. Cuticular specializations reveal presence of eight sensilla on the maxillary galea and eight basiconic sensilla on the apical tip of the maxillary palpus. The two galeal styloconic sensilla are innervated by five neurons with one modified as a structure like a tubular body. Cuticular specializations of conical pegs of the galeal styloconic sensillum and the number of basiconic sensilla on the apical tip of the maxillary palpus vary among different strains and individuals. These structural differences are attributed to strain differences and not to feeding habits of strains.

著者

Ying An Tetsuro Yamashita Atsushi Seino Kunio Imai Koichi Suzuki

出版者

The Japanese Society of Sericultural Science

雑誌

Journal of Insect Biotechnology and Sericology (ISSN:13468073)

巻号頁・発行日

vol.76, no.1, pp.1_51-1_55, 2007 (Released:2008-10-06)

参考文献数

27

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Peptides of the ENF (Glu-Asn-Phe) family, which occur in the hemolymph of Lepidoptera, were reported to act on the plasmatocytes and heart, cause body paralysis, and inhibit body growth. In this paper we report on yet another, most surprising effect. An ENF peptide isolated from the wild silkmoth, Antheraea yamamai, and named Antya-ParP causes paralysis in the caterpillars but not in the pupae of Bombyx mori. However, adults that emerge from the treated pupae lay diapausing eggs. The embryonic diapause of B. mori is normally induced by the diapause hormone (Bommo-DH), which is produced in pupae from the suboesophageal ganglion. The effect of Antya-ParP is independent of this ganglion, showing that the Antya-ParP action is not mediated by Bommo-DH. The sequence of 23 amino acid residues of Antya-ParP shows no similarity to the Bommo-DH sequence of 24 residues. The mode of action of the two peptides seems to be identical but the threshold concentration of Bommo-DH is up to hundred times lower than that of Antya-ParP.

著者

Yoko Takemura Yukina Matsumoto Akio Ohnuma Yuji Mochida Takeshi Yokoyama Katsuhiko Ito

出版者

The Japanese Society of Sericultural Science

雑誌

Journal of Insect Biotechnology and Sericology (ISSN:13468073)

巻号頁・発行日

vol.89, no.2, pp.2_031-2_037, 2020 (Released:2020-07-04)

参考文献数

28

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Many lethal mutations of the silkworm egg have been reported. The lethal phenotype is exhibited at several stages including blastokinesis, head pigmentation, and body pigmentation. We recently isolated a novel lethal mutant, which the skin color of the mature embryo became a light orange and the embryo died before hatching. In this study, we performed morphological observation and genetic analysis of this lethal mutation. Phenotypic observation showed that the phenotype of this lethal mutant is quite similar to that of the sex-linked chocolate lethal (schl), chocolate (ch), chocolate 2 (ch-2), and maternal chocolate (cm) mutants. We first performed the crossing experiment, which revealed that this mutation is regulated by a single recessive gene, and is not linked to the sex chromosome on which the schl mutation is located. We next performed the pre-linkage test with this lethal mutation and three other mutations, which revealed that an allelic relationship among these mutations could not be detected. Therefore, we determined that this is a novel lethal mutant, which we named light orange lethal (l-og). We next performed the linkage analysis of the l-og mutation using 20 F2 individuals and primer sets designed for each chromosome. The linkage analysis revealed that the l-og mutation is definitely located on chromosome 10. Furthermore, the rough mapping using 119 F2 individuals and 7 primer sets designed for chromosome 10 revealed that the l-og-linked region was narrowed down to approximately 3.7 Mb long on chromosome 10.

著者

Tsuguru Fujii Yutaka Banno

出版者

The Japanese Society of Sericultural Science

雑誌

Journal of Insect Biotechnology and Sericology (ISSN:13468073)

巻号頁・発行日

vol.87, no.3, pp.3_071-3_078, 2018 (Released:2019-01-07)

参考文献数

30

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Ge (giant egg) is a sex-linked mutation in Bombyx mori which leads to the production of large-sized eggs caused by an increase in the number of follicular epithelial cells, each with decreased cell size. We previously determined that a gene orthologous to human Phytanoyl-CoA dioxygenase domain-containing 1 (PHYHD1) is specifically disrupted in Ge and Ge2 mutants through positional cloning of the Ge locus. However, little is known about the function of the BmPHYHD1 gene in determination of the egg size. In this study, we knocked out BmPHYHD1 using CRISPR/Cas9. We employed a novel knockout protocol developed in other lepidopteran species in which a commercialized Cas9 mixed with two sgRNAs designed for a target gene is injected into newly-laid eggs. First, we confirmed that the protocol was applicable to B. mori with high efficiency. Second, we targeted the BmPHYHD1 gene and obtained G0 moths laid large size eggs. CRISPR/Cas9-mediated mutations were confirmed in G1 moths that laid large-sized eggs, demonstrating that the BmPHYHD1 gene controls egg size in B. mori. Finally, the dominant/recessive relationship between Ge and +Ge is discussed and we propose the use of gi (giant egg) and gi2 (giant egg 2) to represent giant egg mutations, Ge and Ge2, respectively. We believe that Ge mutants are an appropriate model for the study of genetic mechanisms mediating the size and number of cells in animals.

著者

Yujun Wang Mikihiko Miura Hideaki Morikawa

出版者

(社)日本蚕糸学会

雑誌

Journal of Insect Biotechnology and Sericology (ISSN:13468073)

巻号頁・発行日

vol.72, no.1, pp.71-77, 2003 (Released:2004-10-27)

参考文献数

6

被引用文献数

1

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In a few genetic strains of the silkworm, Bombyx mori, two mature larvae jointly spin a large cocoon called a double cocoon with a high frequency. We measured the behaviour of the silkworm to spin double cocoons and analysed the data to examine the relationships between the two silkworms concerning the sharing of the cocoon construction, the relative positions of the two silkworms, the moving properties and the spinning speed. As a result, we were able to visually show the spinning positions and the sharing of the two silkworms for the construction of the cocoon. The results showed that they fixed their bodies in the same or opposite direction with a high frequency. Furthermore, in one race of double cocoons, pseudo-periodicity existed in the serial change of the angle between the two silkworm bodies. There was a difference between the transition probabilities of the two different kinds of double cocoons. The behaviour of one silkworm affected the movement of the other silkworm in one of the double cocoons, though the two silkworms behaved more independently in the other double cocoon. They moved the spinneret significantly faster when the hind parts of the body were being fixed than when they were moving, although there was no definite difference between the spinning speed of the two silkworms.

著者

Masato Hino Daisuke Morokuma Hiroaki Mon Jae Man Lee Takahiro Kusakabe

出版者

(社)日本蚕糸学会

雑誌

Journal of Insect Biotechnology and Sericology (ISSN:13468073)

巻号頁・発行日

vol.85, no.2, pp.2_021-2_029, 2016 (Released:2016-10-12)

参考文献数

29

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DNA replication is one of key event in cell-cycle progression, yet due to their importance and lethality, the chronological phenotypes of DNA synthesis machineries after the depletion of corresponding genes have proved difficult to study. In the present study, mRNAs for three DNA polymerases, a clamp, and three clamp loaders were gradually depleted from cultured silkworm cells by soaking RNAi. Interestingly, the depletion of these DNA synthesis factors had different effects on the cell growth rate and arrest of cell-cycle progression during time-lapse observation. The depletion of DNA polymerases immediately arrested the cell-cycle progression at the S phase, while that of PCNA, a DNA clamp, required more time to slow cell growth and finally induced apoptosis. Surprisingly, silkworm cells continued to undergo several rounds of cell division when the components of clamp loaders were knocked down.

著者

Hitoshi Mitsunobu Makiko Izumi Kazuhiro Iiyama Hiroyuki Jikuya Jae Man Lee Hiroaki Mon Yutaka Kawaguchi Takahiro Kusakabe

出版者

(社)日本蚕糸学会

雑誌

Journal of Insect Biotechnology and Sericology (ISSN:13468073)

巻号頁・発行日

vol.79, no.3, pp.3_075-3_083, 2010 (Released:2011-09-12)

参考文献数

31

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In eukaryotes, genomic DNA is wrapped around an octamer of the core histone proteins H2A, H2B, H3 and H4. Silkworms have been known to bear holocentric chromosomes and their regulatory mechanisms of chromatin remodeling remain unclear. We have cloned the silkworm canonical core histones and their variants. The H2A variants, H2AX and H2AZ, were highly conserved in the silkworm, whereas the fly has only one H2A variant, H2Av, which is a chimera of H2AX and H2AZ with the function of both molecules. In the silkworm, all histones except for H2AX were ubiquitously expressed in all tested tissues, and H2AX was expressed only in the genital organs. A subcellular localization analysis of the cloned histones using an EGFP fusion construction demonstrated that the behaviors of the histones are the same as those of genomic DNA throughout the cell cycle. The fluorescence intensities of H2AX and H3.3 were weaker than those of the other histones. The incorporation of these histones into chromatin might be restricted due to their specific function in DNA repair and transcription activity. There were two H3 variants, H3.2 and H3.3, in the silkworm; H3.1 was not present. Lysine 9 on H3 was methylated and acetylated in silkworms bearing holocentric chromosomes.