Acoustic evaluation of the vertical distribution of dwarf ayu Plecoglossus altivelis altivelis in Lake Biwa     

Kunio Shirakihara  Masahiko Yoshida  Machiko Nishino  Yoshimi Takao  Kouichi Sawada 《Fisheries Science》2001,67(3):430-435

SUMMARY: The vertical distribution of dwarf ayu Plecoglossus altivelis altivelis in the pelagic waters of Lake Biwa was evaluated from June to September in 1995–97 from eight acoustic surveys using a quantitative echosounder. In each survey, echoes from a depth range of 3 m to the sea bottom were collected at a station every 2.7 s for 24 h together with measurements of vertical profiles of water temperature and chlorophyll-a. The ayu's echoes were identified using an underwater video camera. The ayu were observed near the maximum chlorophyll-a depth and above the thermocline. Their density was highest at depths of 4–11 m with 2–4 individuals/m ³ and was almost zero below 20 m. Echo signs were recorded as having a frequent duration of more than 1 h at night, whereas were of a shorter duration in the day. The fish stay in the epilimnion during the day without any clear vertical migration, but are distributed more uniformly at night. The advantages of remaining in the epilimnion are discussed in terms of food availability and predator avoidance.  相似文献   

Effect of dietary vitamins C and E fortification on lipid metabolism in red sea bream Pagrus major and black sea bream Acanthopagrus schlegeli     

HONG  JI  Ahmad Daud  OM  Takao  YOSHIMATSU  Masahiro  HAYASHI  Tetsuya  UMINO  Heisuke  NAKAGAWA  Masaya  ASANO  Atsushi  NAKAGAWA 《Fisheries Science》2003,69(5):1001-1009

  相似文献   

Distribution of citrus viroids and <Emphasis Type="Italic">Apple stem grooving virus</Emphasis> on citrus trees in Japan using multiplex reverse transcription polymerase chain reaction     

Takao Ito  Nobuyuki Namba  Tsutae Ito 《Journal of General Plant Pathology》2003,69(3):205-207

  相似文献   

MCPB-ethyl疏花对富士苹果授粉受精及胚珠发育的影响   总被引：6，自引：1，他引：6  

曹秋芬  孟玉平  横田清  崔贵梅  青華幸二  寿松木章 《果树学报》2003,20(1):8-11

通过在花期用MCPB-ethyl处理,对富士苹果花粉的发芽、花粉管的伸长以及胚珠的发育等进行了形态方面的观察和探讨,以阐明MCPB-ethyl的疏花机制。结果表明,MCPB-ethyl对花粉的发芽及花粉管的伸长没有影响,整个受精过程与对照相同,没有发现异常。但受精后胚乳核只进行了数次分裂便停止生长,此后珠皮、珠心细胞迅速解体。根据以上结果,认为MCPB-ethyl的疏花效果不是通过影响花粉的发芽或花粉管的伸长阻碍受精所致,而是使胚和胚珠的发育停止,形成离层导致了落花。  相似文献   

Carrier rate of the c.235G>C mutation in the bovine isoleucyl-tRNA synthetase (IARS) gene of Japanese Black cows at Kagoshima prefecture, Japan,and analysis of the metabolic profiling and reproductive performance of heterozygous cows     

Md Shafiqul ISLAM  Urara SHINYA  Mitsuhiro TAKAGI  Takao AKAHOSHI  Akira YABUKI  Shahnaj PERVIN  Tofazzal Md RAKIB  Mohammad Mahbubur RAHMAN  Martia Rani TACHARINA  Osamu YAMATO 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(2):254

Bovine isoleucyl-tRNA synthetase (IARS) disorder, a major cause of weak calf syndrome, is caused by a homozygous missense (c.235G>C) mutation in the bovine IARS gene of Japanese Black (JB) cattle, which was identified in 2013. However, the extent to which the carrier rate has changed at Kagoshima prefecture, Japan, and whether the carrier status is associated with any clinical or reproductive problems, have yet to be ascertained. In this study, using a real-time polymerase chain reaction-based genotyping assay, we determined the carrier rate in a regional JB cow population at Kagoshima prefecture. Comparative analyses were performed on the metabolic profile test (MPT) results and reproductive performance data obtained for heterozygous carrier and homozygous wild-type cows. In 2009 and 2018, DNA samples were collected from 130 and 462 clinically healthy JB cows, respectively, in Kagoshima prefecture. MPT results and reproductive performance data were evaluated for 62 cows, comprising four heterozygous carriers and 58 wild-type cows. Genotyping revealed that the carrier rate was 6.9% in 2009 and 1.5% in 2018, the difference of which was statistically significant (P<0.005). There were no statistically significant differences between the carrier and wild-type cows with respect to either MPT results or reproductive performance, indicating that the carrier cows have necessary IARS activity to maintain minimal health and reproductive potential.  相似文献   

Lactobacillus rhamnosus GG SpaC pilin subunit binds to the carbohydrate moieties of intestinal glycoconjugates          下载免费PDF全文

Keita Nishiyama  Shintaro Ueno  Makoto Sugiyama  Yuji Yamamoto  Takao Mukai 《Animal Science Journal》2016,87(6):809-815

Lactobacillus rhamnosus GG (LGG) is a well‐established probiotic strain. The beneficial properties of this strain are partially dependent on its prolonged residence in the gastrointestinal tract, and are likely influenced by its adhesion to the intestinal mucosa. The pilin SpaC subunit, located within the Spa pili structure, is the most well studied LGG adhesion factor. However, the binding epitopes of SpaC remain largely unknown. The aim of this study was to evaluate the binding properties of SpaC to the carbohydrate moieties of intestinal glycoconjugates using a recombinant SpaC protein. In a competitive enzyme‐linked immunosorbent assay, SpaC binding was markedly reduced by addition of purified mucin and the mucin oligosaccharide fraction. Histochemical staining revealed that the binding of SpaC was drastically reduced by periodic acid treatment. Moreover, in the surface plasmon resonance‐based Biacore assay, SpaC bound strongly to the carbohydrate moieties containing β‐galactoside at the non‐reducing terminus of glycolipids. We here provide the first demonstration that SpaC binds to the oligosaccharide chains of mucins, and that the carbohydrate moieties containing β‐galactoside at the non‐reducing termini of glycoconjugates play a crucial role in this binding. Our results demonstrate the importance of carbohydrates of SpaC for mucus interactions.  相似文献   

Growth Characteristics of Tea Plants and Tea Fields in Japan     

Hiromi Yokota  Akio Morita  Faezeh Ghanati 《Soil Science and Plant Nutrition》2005,51(5):625-627

In 12th century, the Buddhist priest Eisai brought tea ( Camellia sinensis L.) seeds to Japan from China and now tea plants are cultivated all over Japan except in the Hokkaido and Tohoku districts. The quality (reflected in the price) of Japanese green tea is affected by the nitrogen content. Consequently in tea fields, for last three decades large amounts of fertilizer have been applied to produce high quality tea. As a result, problems such as acidification of soil have been caused. It is also known that the growth of tea plants is stimulated by the addition of aluminum (Al) under acidic conditions. In this keynote address, some problems caused by excess applications of fertilizer in tea fields and the growth characteristics of tea plants related to Al are presented.  相似文献   

Sporadic endemicity of zoonotic Paragonimus in raccoon dogs and Japanese badgers from Miyazaki Prefecture,Japan     

Mari ISHIDA  Chiho KANEKO  Takao IRIE  Yoshino MARUYAMA  Asami TOKUDA  Ayako YOSHIDA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2022,84(3):454

Paragonimiasis is a zoonotic trematode infection caused by Paragonimus spp. To determine the recent status of Paragonimus infections in wild animals, this study investigated Paragonimus spp. in 39 raccoon dogs and 54 Japanese badgers from March 2019 to January 2021 in Miyazaki Prefecture, and examined metacercariae in freshwater crabs. Triploid P. westermani was found in one raccoon dog (2.6%), and metacercariae were recovered from Eriocheir japonica captured near the infected animal collected. One Japanese badger (1.9%) harbored P. skrjabini miyazakii; this prevalence was lower than the approximately 30% that was reported in the 1970s. Results indicated that zoonotic Paragonimus was sporadically prevalent in wild animals. Further investigation in various animals is awaited to elucidate current wildlife reservoirs for those Paragonimus.  相似文献   

考虑可控非可控因素动态特性的含水层系统有限元模拟模型   总被引：1，自引：0，他引：1  

刘廷玺  天谷孝夫  贾德彬  史小红  杨·呼和巴拉 《内蒙古农业大学学报(自然科学版)》2002,23(2):115-122

本文提出了考虑可控非可控因素动态特征的水资源系统有限元动态模拟模型，将各单元逐时段系统输入输出信息的动态计算模型引入到模型中，然后由于这些量的动态特性，加之需要模拟识别的参数繁多，给有限元模拟模型的求解工作增加了很大的难度，我们在分析各类参数及曲线精度及物理概念的基础上，先固定一部分参数和曲线，然后从剩余参数的物理概念出发，确定其初值及其相互间的逻辑关系，最后由有限元模拟模型识别出这些参数，通过验证表明了模拟参数的准确性，也充分说明了有限元各项项信息量确定的准确，系统输入输出信息量计算模型合理可靠。  相似文献   

Recent advances in the high-density rotifer culture in Japan     

Takao Yoshimatsu  M. Amzad Hossain 《Aquaculture International》2014,22(5):1587-1603

The success of rapidly growing aquaculture industry depends on the steady supply of fish seeds. Appropriate food for initial larval stages is critical for mass scale fish seed production. Live food found better over artificial food for fish larvae culture. Rotifers have been found to be the best live food for feeding fish larvae in early life stage. Attempts have been made to develop viable techniques for the production of rotifer through batch, continuous, and semi-continuous culture methods. In order to feed increased number of fish larvae, rotifer need to be cultured under high-density method. Various efforts have been made for increasing culture density of rotifer. In Japan, stable high-density culture of rotifer has been developed in commercial scale at a rate of 20,000–30,000 ind. ml^?1. Later on, ultra-high-density rotifer culture (160,000 ind. ml^?1) was found successful, which can fulfill the increased demand for rotifer as fish larval food. Furthermore, a scope of alternative use of rotifer can be explored. The development of the high-density rotifer culture method in Japan has been reviewed. The considerations of the associated nutritional requirements, microbial aspects, and prospects of high-density culture have been discussed.  相似文献