||Kazunori Matsuo, Yoshimi Hirose, Takeshi Yokoyama, Yumiko Nakajima, Yu-Feng Hsu, Yutaka Banno, Discovery of a New Species of Telenomus (Hymenoptera:Scelionidae) Parasitic on Eggs of Bombyx mandarina and Bombyx mori (Lepidoptera: Bombycidae) in Japan and Taiwan
, Journal of Insect Science, 10.1093/jisesa/iey072 Research, 18, 4:10, 1-7, 2018.08, We reared a Telenomus species from eggs of Bombyx mandarina (Moore) (Lepidoptera: Bombycidae) and Bombyx mori (Linnaeus) (Lepidoptera: Bombycidae) in Japan, and from eggs of B. mandarina in Taiwan. Morphological examination revealed that this Telenomus species is new to science. In this article, we describe it as Telenomus moricolus Matsuo et Hirose, sp. nov. Because B. mandarina is considered to be an
ancestor of B. mori, a domestic insect, it is reasonable to assume that B. mandarina is an original host of T. moricolus. This is the second discovery of an egg parasitoid attacking wild and domesticated silkworms, following the first discovery of T. theophilae, a Chinese species. The significance of the discovery of T. moricolus is discussed in relation to examining the effects of host-insect domestication on egg parasitism..
||Shigeki Nakagome, Yumiko Nakajima, Shuhei Mano, Biogeography revealed by mariner-like transposable element sequences via a bayesian coalescent approach, Journal of Molecular Evolution, 10.1007/s00239-013-9581-0, 77, 3, 64-69, 2013.09, Genetic diversity of natural populations is useful in biogeographical studies. Here, we apply a Bayesian method based on the coalescent model to dating biogeographical events by using published DNA sequences of wild silkworms, Bombyx mandarina, and the domesticated model organisms B. mori, both of which categorized into the order of Lepidoptera, sampled from China, Korea, and Japan. The sequences consist of the BmTNML locus and the flanking intergenic regions. The BmTNML locus is composed of cecropia-type mariner-like element (MLE) with inverted terminal repeats, and three different transposable elements (TE), including L1BM, BMC1 retrotransposons, and BmamaT1, are inserted into the MLE. Based on the genealogy defined by TE insertions/deletions (indels), we estimated times to the most recent common ancestor and these indels events using the flanking, MLE, and indels sequences, respectively. These estimates by using MLE sequences strongly correlated with those by using flanking sequences, implying that cecropia-type MLEs can be used as a molecular clock. MLEs are thought to have transmitted horizontally among different species. By using a pair of published cecropia-type MLE sequences from lepidopteran insect, an emperor moth, and a coral in Ryukyu Islands, we demonstrated dating of horizontal transmission between species which are distantly related but inhabiting geographically close region..
||Masako Yokoo, Ryosuke Fujita, Yumiko Nakajima, Mamoru Yoshimizu, Hisae Kasai, Shin-ichiro Asano, Hisanori Bando, Mos1 transposon-based transformation of fish cell lines using baculoviral vectors, Biochemical and biophysical research communications, 10.1016/j.bbrc.2013.08.037, 439, 11, 18-22, 2013.09, Drosophila Mos1 belongs to the mariner family of transposons, which are one of the most ubiquitous transposons among eukaryotes. We first determined nuclear transportation of the Drosophila Mos1-EGFP fusion protein in fish cell lines because it is required for a function of transposons. We next constructed recombinant baculoviral vectors harboring the Drosophila Mos1 transposon or marker genes located between Mos1 inverted repeats. The infectivity of the recombinant virus to fish cells was assessed by monitoring the expression of a fluorescent protein encoded in the viral genome. We detected transgene expression in CHSE-214, HINAE, and EPC cells, but not in GF or RTG-2 cells. In the co-infection assay of the Mos1-expressing virus and reporter gene-expressing virus, we successfully transformed CHSE-214 and HINAE cells. These results suggest that the combination of a baculovirus and Mos1 transposable element may be a tool for transgenesis in fish cells..
||Yuichi Kawanishi, Reiko Takaishi, Miki Morimoto, Yutaka Banno, Si Kab Nho, Hideaki Maekawa, Yumiko Nakajima, A novel maT-type transposable element, BmamaT1, in Bombyx mandarina, homologous to the B. mori mariner-like element Bmmar6, Journal of Insect Biotechnology and Sericology, 77, 1, 45-52, 2008.02, A complex type marner-like element (MLE) was isolated by PCR with genomic DNA of Bombyx mandarina. The clones of this MLE, homologous to the 'Cecropia-ITR-MLE' in BmTNML locus that we have isolated previously from B. mori, were roughly classified into four groups according to the state of inserted elements: (1) Containing a retrotransposon (L1Bm) and another element, (2) containing L1Bm, alone, (3) containing another element alone and (4) without insertions. This inserted element was named BmamaT1, as it was homologous to the B. mori MLE called Bmmar6, which was previously reported to be similar to a maT-family member, Bmmar1. Many of the current Cecropia-ITR-MLE clones had, as the BmamaT1 insertion site, the sequence of TA/TATA, which may be a transposition target site. Moreover, the BmamaT1 elements that inserted into the Cecropia-ITR-MLE region were highly homogeneous, making one group when a phylogenetic tree was made together with BmamaT1 members isolated directly from the B. mandarina genome. Many of the inserted type BmamaT1 elements had complete ORF which: possessed the so-called DDD catalytic triad. All these findings were taken to indicate that a large fraction of the BmamaT1 elements are still highly active..
||Yuichi Kawanishi, Yutaka Banno, Hirofumi Fujimoto, Si Kab Nho, Zhenli Tu, Kazuei Mita, Kozo Tsuchida, Naoko Takada, Hideaki Maekawa, Yumiko Nakajima, Method for rapid distinction of Bombyx mandarina (Japan) from B. mandarina (China) based on rDNA sequence differences, Journal of Insect Biotechnology and Sericology, 77, 2, 79-85, 2008.06, The EcoRI site is located between the 5.8S and 28S rRNA genes in Bombyx mandarina (Japan) (Japanese type rDNA) but is absent in the rDNA of B. mandarina (China)(B. mori type rDNA) including the domesticated B. mori. Digestion of PCR products amplified by primers of both flanking sides of this EcoRI site with EcoRI should only be successful for amplification products of B. mandarina (Japan) containing Japanese type rDNA. The distribution of Japanese type rDNA in Japan, Korea, and China was determined using this rapid detection method. Japanese type was not detected in China or in Korea despite having 27 chromosomes. These findings suggest that the choromosome fusion and the rDNA type separation were independent evolutionary events. Invasion of B. mori chromosome #11 into Japanese B. mandarina (Japan) was examined..
||Naoko Takada, Emiko Yamauchi, Hirofumi Fujimoto, Yutaka Banno, Kozo Tsuchida, Kazuo Hashido, Yumiko Nakajima, Zhenli Tu, Masateru Takahashi, Hiroshi Fujii, Hajime Fugo, Hideaki Maekawa, A novel indicator for radiation sensitivity using the wing size reduction of Bombyx mori pupae caused by γ-ray irradiation, Journal of Insect Biotechnology and Sericology, 75, 3, 161-165, 2006.10, The wings of Bombyx mori are known to become smaller when irradiated with γ-rays at the larval stage. This was considered to be a non-stochastic effect wherein the wing-size reduction curve, plotted vs. the irradiation dose, shows a threshold. Here we propose a new indicator for radiation sensitivity, named the wingless dose 50 (WLD50), which was obtained from the inflection point of wing-size data normalized by the body-size changes and plotted against the irradiation dose. This indicator was confirmed to serve as a tool to compare irradiation sensitivity among B. mori strains..
||Yuichi Kawanishi, Reiko Takaishi, Yutaka Banno, Hirofumi Fujimoto, Si Kab Nho, Hideaki Maekawa, Yumiko Nakajima, Sequence comparison of mariner-like elements among the populations of Bombyx mandarina inhabiting China, Korea and Japan, Journal of Insect Biotechnology and Sericology, 76, 2, 79-87, 2007.06, Mariner-like elements (MLEs) were isolated from Chinese, Korean and Japanese individuals of Bombyx mandarina by the long PCR methods using the inverted terminal repeat of the Hyalophora cecropia MLE as a primer. The amplified clones of about 1.3 kbp in size were regarded to be full-length MLEs and termed Cecropia-ITR-MLEs. The sequences of the elements were determined, trimmed to eliminate any insertions and used to construct a phylogenetic tree. As a result, the Cecropia-ITR-MLE sequences of B. mandarina could be divided into major groups here called the Continental type and the Japanese type. Chinese and Korean specimens mostly belonged to the former group, which is very diverse and may well consist of subgroups. A majority of Honshu (the main island of Japan) specimens belonged to the latter, which is a much more closely related group of sequences. Interestingly, Tsushima (south of Korea) and Hokkaido (close to Russia) specimens mainly fell into the former type, whereas Fukuoka (south of Tsushima) individuals included both..
||Yumiko Nakajima, Takashi Nakamura, Yutaka Banno, Hirofumi Fujimoro, Kazuo Hashido, Teiichiro Shino, Kozo Tsuchida, Naoko Takada, Hideaki Maekawa, Comparison of mariner-like elements among Bombyx mandarina individuals inhabiting East Asia in the light of the segregation of B. mori and B. mandarina genomes, International Journal of Wild Silkmoth & Silk, 8, 57 -64, 2003.01.
||Yumiko Nakajima, Hirofumi Fujimoto, Tsutomu Negishi, Kazuo Hashido, Teiichiro Shiino, Kozo Tsuchida, Michio Hidaka, Naoko Takada, Hideaki Maekawa, Possible horizontal transfer of mariner-like sequences into some invertebrates including lepidopteran insects, a grasshopper and a coral, Journal of Insect Biotechnology and Sericology, 71, 3, 109-121, 2002.10, Marine-like elements (MLEs) were amplified by PCR against genomic DNAs from several Japanese lepidopteran species, using the inverted terminal repeats (IR) of the Hyalophora cecropia MLE as a primer. Clones thus obtained were of a size of about 1.3 kb, and expected to contain the full-length MLE. A 1.3-kb band was also amplified against genomic DNA from the grasshopper, Traulia ornata, and from a coral allocated to the Fungia family. All of the 1.3-kb bands were cloned and analyzed for nucleotide sequence. Multi-alignment analyses of the results indicated that the clones were highly similar to each other and classified into the cecropia subfamily of MLEs. The coral MLE was found to have a complete ORF coding for transposase, a situation similar to that previously found in the Emperor moth, Attacus atlas, from the Ryukyu island. These findings, together with the fact that all of the insects and coral species that exhibited a positive signal for the full-length MLE were collected in relatively close regions around Japan, indicated that the horizontal transfer of MLEs had taken place even among phylogenetically remote organisms..
||K. Funatsuki, K. Hashido, M. Matsunami, Y. Kameoka, K. Iwabuchi, H. Tsukeda, K. Tsuchida, N. Takada, Yumiko Nakajima, H. Maekawa, Rapid identification of Bombyx mori cells using PCR amplification following a direct procedure for genomic DNA preparation, Journal of Insect Biotechnology and Sericology, 70, 2, 129-136, 2001.02, In cultured cells, karyotypes and genomic dose are variable, especially in ones passaged for a long time. We have improved a method for the genome confirmation of cultured cells of the silkworm, Bombyx mori. A rapid, simple procedure was developed for direct extraction of genomic DNA from cultured cells which has two main steps of proteinase K treatment and heating, without phenol extraction. Genomic characterization is based on PCR amplification of three known genes which vary in copy number and chromosome location. The retrotransposon, BMC1, is dispersed in the genome; rDNA is clustered in one locus; and the fibroin gene is single copy. These genes were sufficient to identify cells as Bombyx mori for comparing among the other species. It was shown that this method could also be used for genotyping and strain identification using larval hemolymph samples..
||Yumiko Nakajima, Kazuo Hashido, Kozo Tsuchida, Naoko Takada, Teiichiro Shiino, Hideaki Maekawa, A novel tripartite structure comprising a mariner-like element and two additional retrotransposons found in the Bombyx mori genome, Journal of Molecular Evolution, 10.1007/PL00006500, 48, 5, 577-585, 1999.05, A clone of a DNA-mediated mobile element (transposon) corresponding to a mariner-like element (MLE) was obtained by carrying out the polymerase chain reaction with genomic DNA of Bombyx mori using a Hyalophora cecropia MLE sequence as a primer. This clone had a size of about 4.2 kb and, after sequencing, was found to contain an RNA-mediated, shorter retrotransposon named L1Bm, which was in turn integrated with a much longer retrotransposon named BMC1. Thus, the mobile elements made a novel tripartite structure. The BMC1 and L1Bm moieties of the composite structure each contained a 63-bp conserved sequence which was subsequently found to be highly conserved in all BMC1 and L1Bm elements registered so far. We propose that the 63-bp stretch may be a recognition site for a retrotransposition mechanism conducted by a reverse transcriptase and an endonuclease complex. On the basis of this inference, we propose a model that predicts how different types of BMC1 and L1Bm elements are dispersed in the genome. In addition, a phylogenetic tree made from the current and extant BMC1 and L1Bm sequences indicated that these elements can be classified into Subfamilies I and II..
||Yumiko Nakajima, Masaru Nagamine, Kazuo Hashido, Kozo Tsuchida, Teiichiro Shiino, Toshihiko Hayashi, Hldeaki Maekawa, Isolation of a mariner-like sequence containing a complete open reading frame for transposase from Attacus atlas and its phylogenetic relationships within the Ditrysia of Lepidoptera, Journal of Insect Biotechnology and Sericology, 10.11416/kontyushigen1930.67.271, 67, 4, 271-278, 1998.07, A complete open reading frame (ORF) encoding a transposase was found in the mariner-like element of the Emperor moth (Yonaguni-san), Attacus atlas. The transposase sequence was isolated by PCR amplification using primers derived from the inverted terminal repeat of Hyalophora cecropia. Within the ORF of the transposase sequence, two consensus sequences and a D, D (34) D motif were found. The sequence of A. atlas was homologous to mariner-like elements from Bombyx mori, H. cecropia, Manduca sexta, Sitotroga cerealella and Ephestia cautella. These results suggested that the mariner-like elements and the inverted terminal repeat may be conserved among Bombycoidea and related species of Ditrysia. Bmmarl, previously reported to be an element from B. mori, showed very low homology compared to sequences from Lepidoptera and other insect groups..
||Tsuyoshi Asato, Yumiko Nakajima, Masaru Nagamine, Yasutsugu Nakashima, Hiroshi Takei, Toshiyuki Maehama, Takenobu Yamashiro, Masahiro Higashi, Michio Nakayama, Koji Kanazawa, Correlation between the Progression of Cervical Dysplasia and the Prevalence of Human papillomavirus, The Journal of Infectious Diseases, 10.1093/infdis/169.4.940, 169, 4, 940 -941, 1994.04,