著者

Atsushi Miyashita Kazuhisa Sekimizu Chikara Kaito

出版者

International Research and Cooperation Association for Bio & Socio-Sciences Advancement

雑誌

Drug Discoveries & Therapeutics (ISSN:18817831)

巻号頁・発行日

pp.2022.01058, (Released:2022-09-06)

参考文献数

25

---

Male crickets emit acoustic signals (i.e., songs) by chirping using their forewings. Although the mechanisms and adaptive functions of these songs are well studied, knowledge about how songs develop within a generation is relatively scarce. Our previous work demonstrated a stable peak frequency at 5.7 kHz in the calling songs recorded from mature adult male crickets (Gryllus bimaculatus). In the present study, we monitored changes in the frequency component over time from the sexual maturity stage (early adult stage). We recorded 300 calling songs from a pool of 122 adults. The peak frequency distribution was lower and unstable (i.e., greater coefficient of variance) in the early adult stage. The mean peak frequency was 4.9 kHz on day 3, but gradually converged to 5.8 kHz over the 2-week adult stage. Immature adult males (emitting immature songs) produced an appropriately tuned song with a peak frequency of 5.8 kHz in an environment of 80% helium and 20% oxygen. These results suggest that the frequency component of the calling song is acquired during the early to mid-adult stage, and may be related to sexual maturation in males. Findings from the helium substitution experiment revealed that physical resistance from surrounding gas molecules negatively affect the stability of male singing, and that muscle development and forewing hardening may contribute to the maturation of singing, suggesting that females may adaptively select sexually mature males based on song traits.

著者

Hiroko Maruki-Uchida Masahiko Sai Kazuhisa Sekimizu

出版者

International Research and Cooperation Association for Bio & Socio-Sciences Advancement

雑誌

Drug Discoveries & Therapeutics (ISSN:18817831)

巻号頁・発行日

pp.2017.01051, (Released:2017-10-30)

参考文献数

15

被引用文献数

1 2

---

We evaluated the innate immune-stimulating activity of amazake using a silkworm muscle contraction assay. Sake cake, a raw material used to make amazake, had high innate immunity-stimulating activity, whereas rice malt, another raw material used to make amazake, did not, even after fermentation. These results suggest that the silkworm muscle contraction assay is a useful tool to screen foods with high innate immune-stimulating activity and that amazake made from sake cake has immunomodulatory potential.

著者

Makoto Urai Keiko Kataoka Satoshi Nishida Kazuhisa Sekimizu

出版者

International Research and Cooperation Association for Bio & Socio-Sciences Advancement

雑誌

Drug Discoveries & Therapeutics (ISSN:18817831)

巻号頁・発行日

vol.11, no.5, pp.230-237, 2017-10-31 (Released:2017-11-22)

参考文献数

22

被引用文献数

7

---

Vegetables are eaten as part of a healthy diet throughout the world, and some are also applied topically as a traditional medicine. We evaluated the innate immunostimulating activities of hot water extracts of various vegetables using the silkworm muscle contraction assay system, and found that broccoli, Brassica oleracea var. italica, contains a strong innate immunostimulant. We purified the innate immunostimulant from broccoli, and characterized the chemical structure by chemical analyses and NMR spectroscopy. The innate immunostimulant comprised galacturonic acid, galactose, glucose, arabinose, and rhamnose, and had a pectic-like polysaccharide structure. To determine the structural motif involved in the innate immunostimulating activity, we modified the structure by chemical and enzymatic treatment, and found that the activity was attenuated by pectinase digestion. These findings suggest that a pectic-like polysaccharide purified from broccoli has innate immune-stimulating activity, for which the polygalacturonic acid structure is necessary.

著者

Satoshi Nishida Yasuo Ono Kazuhisa Sekimizu

出版者

International Research and Cooperation Association for Bio & Socio-Sciences Advancement

雑誌

Drug Discoveries & Therapeutics (ISSN:18817831)

巻号頁・発行日

vol.10, no.1, pp.49-56, 2016 (Released:2016-03-12)

参考文献数

34

被引用文献数

4 27

---

Lactic acid bacteria (LAB) have been thought to be helpful for human heath in the gut as probiotics. It recently was noted that activity of LAB stimulating immune systems is important. Innate immune systems are conserved in mammals and insects. Silkworm has innate immunity in response to microbes. Microbe-associated molecular pattern (ex. peptidoglycan and β-glucan) induces a muscle contraction of silkworm larva. In this study, we established an efficient method to isolate lactic acid bacteria derived from natural products. We selected a highly active LAB to activate the innate immunity in silkworm by using the silkworm muscle contraction assay, as well. The assay revealed that Lactococcus lactis 11/19-B1 was highly active on the stimulation of the innate immunity in silkworm. L. lactis 11/19-B1 solely fermented milk with casamino acid and glucose. This strain would be a starter strain to make yogurt. Compared to commercially available yogurt LAB, L. lactis 11/19-B1 has higher activity on silkworm contraction. Silkworm normally ingested an artificial diet mixed with L. lactis 11/19-B1 or a yogurt fermented with L. lactis 11/19-B1. Interestingly, silkworms that ingested the LAB showed tolerance against the pathogenicity of Pseudomonas aeruginosa. These data suggest that Lactococcus lactis 11/19-B1 would be expected to be useful for making yogurt and probiotics to activate innate immunity.

著者

Yasuhiko Matsumoto Kazuhisa Sekimizu

出版者

バイオ&ソーシャル・サイエンス推進国際研究交流会

雑誌

Drug Discoveries & Therapeutics (ISSN:18817831)

巻号頁・発行日

vol.10, no.1, pp.14-18, 2016 (Released:2016-03-12)

参考文献数

26

被引用文献数

6

---

Silkworm shows hyperglycemia after intake of diet containing large amount of glucose. The hyperglycemic silkworm model is useful for evaluation of anti-diabetic drugs. A hot water extract of Rehmanniae Radix, an herbal medicine, showed hypoglycemic effect against the hyperglycemic silkworms. This method is applicable for quick and simple evaluation of the hypoglycemic activities of different batches of Rehmanniae Radix. Our findings suggest that silkworms have a lot of merit as experimental animals for evaluation of various herbal medicines.

著者

Atsushi Miyashita Yuuki Hirai Kazuhisa Sekimizu Chikara Kaito

出版者

バイオ&ソーシャル・サイエンス推進国際研究交流会

雑誌

Drug Discoveries & Therapeutics (ISSN:18817831)

巻号頁・発行日

pp.2015.01000, (Released:2015-01-25)

参考文献数

11

被引用文献数

2 16

---

The search for new antibiotics or antifungal agents is crucial for the chemotherapies of infectious diseases. The limited resource of soil bacteria makes it difficult to discover such new drug candidate. We, therefore, focused on another bacterial resource than soil bacteria, the microbial flora of insect species. In the present study, we isolated 40 strains of bacteria and fungi from the mycangia of three species of stag beetle, Dorcus hopei binodulosus, Dorcus rectus, and Dorcus titanus pilifer. We identified those species with their ribosomal DNA sequences, and revealed that Klebsiella spp. are the most frequent symbiont in the stag beetle mycangia. We examined whether these microorganisms produce antibiotics against a Gram-negative bacterium, Escherichia coli, a Gram-positive bacterium, Staphylococcus aureus, or a fungus, Cryptococcus neoformans. Culture supernatants from 33, 29, or 18 strains showed antimicrobial activity against E. coli, S. aureus, or C. neoformans, respectively. These findings suggest that bacteria present in the mycangia of stag beetles are useful resources for screening novel antibiotics.