[Obituary] Professor Frantisek Sehnal

Frantisek Sehnal, a distinguished entomologist, a member of Editorial Advisory Board of the journal, International Journal of Wild Silkmoth and Silk, since 2001 and an honorary member of The Entomological Society of America since January 2008, died Friday, November 26, 2021 at the age of 83. He attended many times the International Conference on Wild Silkmoths and made presentations. He was a leading researcher in the field of insect physiology, particularly, hormonal control of insect development and function of silk gland related to silk protein synthesis.

Professor Sehnal was born in September 11, 1938 in Czechoslovakia. At the university, he majored in Biology and Chemistry and made a Ph.D. study under the instruction by Dr. Vladimir Novak and obtained Ph.D. degree. From 1966 to 1968, he worked as a postdoctoral fellow at the Laboratory of Dr. Howard A. Schneiderman, Case Western Reserve University, Cleveland, USA. I became the postdoctoral fellow at the same time as Professor Sehnal and at the same Laboratory and enjoyed research life with him. He returned to Czechoslovakia and obtained a permanent position at the Entomological Institute of the Czech Academy of Sciences. He studied, at first, ecophysiology of caddisflies, but realized that studies on action of juvenile hormone and juvenoids were needed. For this research, in 1972, he received Steinhouse Memorial Lectureship Award from the University of California, Irvine, USA. Then he studied neurohormones and silk composition. For this research, in 1987, he received the Japanese Government Award for Foreign Specialists. He became a professor at the University of South Bohemia in Czech Republic. He served from 1992 to 1995 as University Vice-Rector for Foreign Affairs. In 1995, he became the Director of the Entomological Institute. In 2007, he was named Director of the Biology Center of the Czech Academy of Sciences until 2012.

His research interests were from oxidative stress, circadian rhythms, environmental impact of genetically modified crops, to nature conservation.

Today, number of insect researchers in EU is decreasing and many research institutes of insects in EU are abolished accordingly. In Czech Republic, however, the Entomological Institute is maintained, and outstanding research achievement is being produced. I believe that this is due to the contribution and achievement by Professor Sehnal.

Professor Sehnal made a research for a long time. He taught 17 Ph.D. students. He obtained 22 patents and published more than 250 papers. He served editorial boards of ten journals. I praise these achievements of his and I would like to express my deepest sympathy to his soul.

Hiromu Akai

President of International Society of Wild Silkmoths

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[Obituary] Professor Koichi Suzuki

Professor Koichi Suzuki, a member of The Japanese Society for Wild Silkmoths and an Editorial Board member of the International Journal of Wild Silkmoth and Silk, since the establishment of the society and the journal (1994) had gone on Saturday, January 15, 2022 at 75 years old. His contribution for the journal publication was 4 papers, and 2 paper contribution was also enclosed in books of the WILD SILKMOTHS ’88 (edited by Akai H and Wu ZS) and the WILD SILKMOTHS ’89･’90 (edited by Akai H and Kiuchi M). He attended several International Conference on Wild Silkmoths and presented 3 times Keynote and Plenary lectures.

Professor Suzuki was bone in Ishikoshi machi, a most northern part of Miyagi prefecture, Japan. After graduating from Faculty of Agriculture, Iwate University, he selected Nagoya University to start scientific study in insect physiology supervised by professors Kinsaku Hasegawa and Okitsugu Yamashita. Just after the start of his doctoral study he was employed in Iwate University. With the scientific works as well as university education for 14 years he successfully defended doctor theses in Nagoya University and became an associate professor. Since then, one of his scientific interests faced in diapause mechanism in the Japanese oak silkmoth, Antheraea yamamai. During his carrier he found that an imidazole compound, KK-42 terminates pharate first instar diapause of A. yamamai. He proposed the mode of action against the diapause maintenance peptide, yamamarin, and applied to rear the larvae twice a year for wild silk production in Quercus field. He also found A. yamamai paralytic peptide mimicked Bombyx mori diapause hormone. The molecular mechanisms and mode of action is still being analyzed by his former doctoral student.

Professor Suzuki supervised 30 doctoral students and many master and bachelor students. He published more than 100 papers and more than 25 review/book chapters. After retirement in his university carrier, he worked as a chief in BioCocoon Laboratories. In the very recent paper, he found a novel cyclic peptide, named “Naturido” (means “child of nature” in Esperanto) may be a possible candidate of glia-neuron modulator for the treatment of not only senescence but also Alzheimer’s disease and other neurodegenerative diseases. I regret very much for his death. Hoping all readers keep his valuable contribution to the International Journal of Wild Silkmoth and Silk and his achievement of researches in Antheraea yamamai in your memories.

Ken Sahara
Professor, Laboratory of Applied Entomology, Faculty of Agriculture, Iwate Universi

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[Obituary] Professor Koichi Suzuki

Koichi Suzuki, a prominent entomologist, an Emeritus Professor of Iwate University, Japan, a member of Editorial Advisory Board of the journal, International Journal of Wild Silkmoth and Silk, since 1994 died on Saturday, January 15th, 2022 at the age of 75. He was a pioneering researcher in the field of insect diapause. In 1986 he developed a method of breaking diapause in the wild silkmoth, Antheraea yamamai using KK-42. Recently, he searched active substances in the winter insect summer grass, isolated ‘Naturido’, determined its chemical structure and published a paper in 2021 which proposed as a modulator of glia-neuron interactions. He worked as a fellow of BioCocoon Co. Ltd. to utilize academic research achievement for human welfare.

Professor Suzuki studied in graduate school at Nagoya University, in the master course and a part of Ph.D. course, Faculty of Agriculture, Laboratory of Sericulture. I was in the same laboratory, two grades younger than Professor Suzuki. He advised me in several occasions. Later he worked at the University of Arizona, Tucson, USA as a postdoctoral fellow in the Laboratory of Dr. Bowers. I had worked at the University of Arizona earlier, from 1985 to 1986, in the Laboratory of Dr. John H. Law. We were alumnus in Japan and USA. I believe Professor Suzuki visited Arizona Sonora Desert Museum in the suburb of Tucson to see huge cacti all over the hills and enjoyed barbecue in hot weather of Arizona.

In 2006, Professor Suzuki summarized his studies of 20 years on diapause in wild silkmoths in Sanshi-Konchu Biotech. I highly regard his great efforts for elucidating the molecular mechanisms. He must have felt much stress. The difficulties in advancing the studies must have come from the degree of advancement of biology at the time. Professor Suzuki always thought of the application of achievement in fundamental study to human welfare. He could find ‘Naturido’ through his studies and I suppose he was happy. I thank Professor Suzuki. He kindly advised me to advance the study of fibroinase of silk gland around 1994 when I was wondering if I should go to the purification of it. He advised me to publish good papers in the Journal of Insect Biotechnology and Sericology, a journal published by The Japanese Society of Sericultural Science, possibly because he was a member of the Editorial Board.

My deepest sympathies. I pray that he rests in peace.

Motoyuki Sumida
Mahasarakham University, Maha Sarakham 44150, Thailand

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We conducted an extrachromosomal interplasmid transposition assay using the lepidopteran piggyBac transposon in embryos of the eri silkworm Samia ricini. To construct the transposition assay system, expression of the piggyBac transposase in embryos is required. We first measured the promoter activity of the upstream region of the cytoplasmic actin 3 gene (BmA3) of the mulberry silkworm (Bombyx mori) in eri embryos by the luciferase assay and found that the BmA3 promoter worked well in eri silkworms. We then constructed a helper plasmid expressing piggyBac transposase in eri embryos using the BmA3 promoter and tested for transposition activity in interplasmid transposition assays to determine whether or not the piggyBac element works. The piggyBac element was inserted into the TTAA sequences on the acceptor plasmid and the frequency of transposition was high. Based on these results, we concluded that the piggyBac transposon can serve as an effective vector for germ-line transformation in the eri silkworm.

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Center of Excellence for Silk Innovation (CESI), Mahasarakham University (MSU) is an institute which supports sericulture activities in northeastern Thailand from the university sector. CESI was established in 2014 based on Silk Innovation Center (SIC), MSU, which was established in 2000 and had been functioning until 2014. Since 2014, CESI has been performing activities that SIC had been playing with one more activity. This case study evaluated the activities of CESI for the past seven years and proposed the topics for the future.

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The silkworm, Bombyx mori, feeds primarily on mulberry, Morus alba. Instead, the Non-preference Shokei, Nps, mutant has different food habit trait which allows the larvae to feed on a considerable number of plants and artificial diets unpalatable to the normal silkworm. How the Nps allele affects feeding behavior is not known. In this study, the behavioral responses to feeding deterrents together with the electrophysiological responses and the morphology of the central projections of the taste neurons were compared between Nps mutant and normal larvae. By comparing parameters such as the latency to the first sustained feeding and total time spent on feeding under 45 minutes of observation, deterrent effects of salicin and strychnine nitrate were significantly lower in Nps larvae than in normal larvae. Dose-response relationships for sucrose, myo-inositol, salicin and strychnine nitrate recorded from the galeal styloconic sensilla and their temporal patterns of spike firing were almost identical between the genotypes. These results suggest a presence of alteration in the central nervous system, which causes the abnormal feeding behavior of the Nps larvae. One of the possibilities of the feeding difference relates in the axonal central projections of the taste neurons. However, whole mount observations of anterograde-filled neurons from each galeal styloconic sensillum with a cobalt-lysine complex have not visibly made a clear difference between the genotypes.

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Composition of artificial diet, M–25, that has been used for germfree rearing of bivoltine silkworm strains in the Laboratory of Kyoto Institute of Technology (KIT), Japan was presented. The components in vitamin B group mixture in KIT diet was comparable with that in National Institute of Sericultural and Entomological Science, Japan and further possibility to develop new diets for the silkworm was discussed.

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We observed a big nest of Japanese paper wasp, Polistes nipponensis, on the farm of Tsuchiura-city and examined the construction process and the development of its eggs and larvae during the founding, worker, and reproductive phases. The wasp is known to make small nests consisting of 30–50 cells. However, the nest we observed was of 118 cells, consisting of 32, 62, and 24 cells created in the above three phases. The numbers of eggs laid were 31, 79, and 105 in the three phases. We found that some of the cells were reused up to three times. The growth rate of the wasp generally depends on temperature. However, it was faster in the early term than that of the late during the founding phase although the temperature was gradually increasing. In the outer area of the nest, the eggs were preferentially laid in the inner cell wall towards the nest stem. In the middle area they were laid in a manner that was just easier for the wasp, especially in the reuses of the cells. The building of nest cells appeared to depend on the growth status of larvae and the appearance of adults in the colony.

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