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1.
Yohei Kato 《Pesticide biochemistry and physiology》2004,79(2):64-73
A hydrophilic form of acetylcholinesterase (AChE) was purified from N-methyl carbamate susceptible (SA) and highly N-methyl carbamate-resistant (N3D) strains of the green rice leafhopper (GRLH), Nephotettix cincticeps Uhler. Both of purified AChE from SA and N3D strains displayed the highest activities toward acetylthiocholine (ATCh) at pH 8.5. In the SA strain, the optimum concentrations for ATCh, propionylthiocholine (PTCh), and butyrylthiocholine (BTCh) were about 1 × 10−3, 2.5 × 10−3, and 1 × 10−3 M, respectively. However, in the N3D strain, substrate inhibition was not identified for ATCh, PTCh, and BTCh to 1 × 10−2 M. The Km value in the SA strain was 51.1, 39.1, and 41.6 μM and that in the N3D strain was 91.8, 88.1, and 85.2 μM for ATCh, PTCh, and BTCh, respectively. The Km value in the N3D strain indicated about 1.80-, 2.25-, and 2.05-fold lower affinity than that of the SA strain for ATCh, PTCh, and BTCh, respectively. The Vmax value in the SA strain was 70.2, 30.5, and 4.6 U/mg protein and that in the N3D strain was 123.0, 27.0, and 14.5 U/mg protein for ATCh, PTCh, and BTCh, respectively. The Vmax value in the N3D strain was 1.75- and 3.15-fold higher for ATCh and BTCh than that in the N3D strain. However, it was 1.13-fold lower for PTCh. The increased activity of AChE in the N3D strain is due to the qualitatively modified enzyme with a higher catalytic efficiency. The bimolecular rate constant (ki) for propoxur was 27.1 × 104 and 0.51 × 104 M−1 min−1 in the SA and N3D strain and that for monocrotophos was 0.031 × 104 and 2.0 × 104 M−1 min−1 in the SA and N3D strain. AChE from the N3D strain was 53-fold less sensitive than SA strain to inhibition by propoxur. In contrast, AChE from the N3D strain was 65-fold more sensitive to inhibition by monocrotophos than AChE from the SA strain. This indicated negatively correlated cross-insensitivity of AChE to propoxur and monocrotophos. 相似文献
2.
Hisayuki Arakawa Yohei Ohi Akira Matsumoto Kenji Takio Takumi Kimoto Katsutoshi Kawabe 《Fisheries Science》2012,78(5):1083-1090
The populations of red alga Gelidium elegans along the coast of Miyakejima Island were severely damaged by a volcanic eruption in 2000. The effect of this volcanic eruption has been long lasting, and populations of this red alga still have not recovered. We investigated the effect of seabed sediment particles derived from volcanic ash on the substrate adhesion of G.?elegans spores. The analysis provides evidence that increasing amounts of sediment particles result in lower adhesion rates of G.?elegans spores, and that smaller sediment particles have a greater influence on adhesion. The amount of seabed sediment particles around Miyakejima Island was 9.3?C1815.4?mg/cm2. This amount has changed greatly from year to year. The adhesion rate of G.?elegans spores in water around Miyakejima Island was 0?% at all points in 2008 and 2010, but it was estimated as 6.3?C38.6?% in 2009. These results suggest that there is significant inhibition of algal spore adhesion by seabed sediment particles derived from volcanic ash around Miyakejima Island. 相似文献
3.
Yohei Kawasaki Ryo Yamazaki Katsuyuki Katayama Tetsuya Yamada Hideyuki Funatsuki 《Plant Production Science》2013,16(4):387-397
ABSTRACTUnderstanding how maturity genes affect soybean yield formation will provide important information for crop management decisions. This study aimed to reveal how maturity genes E2 and E3 in the soybean cultivar ‘Enrei’ affect yields and yield formation in warm regions of Japan. ‘Enrei’ (e2e3) and three near-isogenic lines of ‘Enrei’ (e2E3, E2e3, and E2E3) were cultivated in 2016 and 2017 in Fukuyama, Japan (34°30′N, 133°23′E). Two sowing dates were set in each year (June sowing and July sowing). E2 extended the period from emergence to R1 and also the period from R1 to R7, whereas E3 extended only the period from emergence to R1. Interaction between E2 and E3 did not affect duration of the period from emergence to R1, but did affect the period from R1 to R7. Although seed yield did not differ between genotypes in the June sowings, the effects of E2 and E3 on seed yield in July sowing were both significant and interaction between E2 and E3 also observed. The total number of nodes increased in E3 genotypes in both sowing dates, especially in E2E3. Pod-set ratio was lower in E2 and E3 genotypes than in e2 and e3 genotypes in the June sowings, but did not differ between genotypes in the July sowings. The high yield of E2E3 genotypes in the July sowings was attributed to increased number of nodes and flower production while maintaining pod-set ratio. Appropriate choice of sowing date is suggested to be essential when using E3 genotypes.Abbreviations: HI: harvest index; NIL: near-isogenic line; RUE: radiation use efficiency; TDM: total above-ground dry matter; TRI: total solar radiation intercepted 相似文献
4.
Yohei Nakamura Masahiro Horinouchi Mitsuhiko Sano Takuro Shibuno 《Fisheries Science》2009,75(6):1401-1408
Whilst the importance of seagrass beds as nurseries for coral reef fishes has been clearly recognized, the vast majority of
early studies on fish nursery habitats emphasized the close proximity of the latter to coral reefs. To determine the potential
nursery role of isolated seagrass beds, we investigated the degree to which juvenile emperor fishes (Lethrinidae) utilized
seagrass beds in the presence/absence of adjacent coral habitats at Ishigaki Island (southern Japan), such fishes being known
to use seagrass beds as nurseries. Seagrass beds in close proximity to coral habitats (distance between the two habitats of
50–200 m) had greater densities of lethrinid juveniles than those without adjacent coral habitats (2.5–4 km) for 3 different
sites investigated, although a significant difference was obtained only for 1 site. Juveniles of Lethrinus atkinsoni, L. obsoletus, L. harak, and L. nebulosus were observed in seagrass beds with and without adjacent coral habitats, whereas L. ornatus occurred only in the former. Overall, most lethrinid juveniles utilize seagrass beds irrespective of the presence of adjacent
adult coral habitat, suggesting that both types of seagrass beds would contribute to lethrinid adult populations. Therefore,
management efforts for lethrinid populations should be applied not only to contiguous coral-seagrass habitat systems but also
to isolated habitats. 相似文献
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Yohei Kawauchi Masayuki Chimura Takashi Mutoh Masamichi Watanobe Hokuto Shirakawa Kazushi Miyashita 《Fisheries Science》2014,80(2):139-149
We examined factors affecting the vertical distribution of juvenile walleye pollock during “the second critical period” (i.e. the transition period of prey size) in and around Funka Bay, Hokkaido, Japan. During the day, small juveniles (<30 mm) were distributed mainly in shallow, warm, and low-salinity water within the bay, whereas larger ones (≥30 mm) occurred in deeper, cold and saline water. During the night, the large juveniles migrated to shallower depths. Outside the bay, small- and large-sized juveniles were distributed in water masses of similar physical properties during the daytime, whereas during the nighttime, most of the juveniles moved to shallower depth, and some juveniles dived to deeper water mass. Dietary analysis revealed that large juveniles fed on large copepods (≥0.5 mm in body width) more than small juveniles did. The composition of zooplankton in our survey area showed that large-sized copepods often occurred in deeper saline water. From these results, there is a possibility that juvenile pollock inside and outside Funka Bay occupied different water masses preferable for each feeding advantage. 相似文献
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Asada Yohei Kimura Masaomi Azechi Issaku Iida Toshiaki Kubo Naritaka 《Paddy and Water Environment》2019,17(3):351-358
Paddy and Water Environment - Leakage of agricultural pipes has been increasingly frequent problems due to corrosion, loosening of joints, and cracks, which result in the subsidence of peripheral... 相似文献
10.
Daito T Fujino K Watanabe Y Ikuta K Tomonaga K 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2011,73(9):1243-1247
Borna disease virus (BDV) is a non-segmented, negative-strand RNA virus that is characterized by nuclear replication and persistent infection. A unique feature of BDV is that it releases only a small number of infectious particles from infected cells. Although these characteristics might make it difficult to obtain a large amount of recombinant viruses in a reverse genetics system, the mechanism underlying the budding or assembly of BDV particle has remained largely unknown. In this study, as a first step toward understanding the virion formation of BDV, we investigated the intracellular distribution and mobility of the fluorescent marker fusion envelope glycoprotein (G) of BDV in living cells. Expression analysis revealed that fusion proteins seem to cleave into functional subunits and localize in the endoplasmic reticulum (ER)/Golgi apparatus, as well as the authentic BDV G. Furthermore, we demonstrated using fluorescence recovery after photobleaching analysis that BDV G fluorescence shows rapid recovery in both the ER/Golgi and plasma membrane regions, indicating that BDV G fusion protein may be a useful tool to investigate not only the maturation of BDV G but also the budding and assembly of BDV particles in living cells. 相似文献