Enhanced local recruitment of glass eel <Emphasis Type="Italic">Anguilla japonica</Emphasis> in Oyodo River,Miyazaki and offshore environmental conditions in 2002     

Kazuhiro Aoki  Toshihiro Yamamoto  Nobuto Fukuda  Kazuki Yokouchi  Hiroaki Kurogi  Takashi Setou  Hiroshi Kuroda  Takahiko Kameda  Kazuhiro Takafuji  Tsutomu Tokeshi 《Fisheries Science》2018,84(5):777-785

To examine the environmental factors controlling the inshore recruitment dynamics of Anguilla japonica in the Oyodo River, Miyazaki Prefecture, Kyushu, glass eel samplings were carried out using fyke nets during winter (November–March) of 1994–2014. The peak CPUEs (catch per unit effort) were observed between November and February, but differed from year to year. The yearly CPUE was extremely high in 2002, when the sea surface temperature (SST) in the offshore area of the Oyodo River was the lowest in winter of all the sampling years. The negative SST anomaly of less than ? 0.5 °C was sustained in the offshore area during the recruitment season in 2002, which was caused by two combined factors; low air temperature and the Kuroshio path. The oceanographic data showed that the dominant path of the Kuroshio was displaced eastward at 31°N in 2002, which was different from the average Kuroshio path. The eastward displacement of the Kuroshio induced a cyclonic mesoscale eddy in the offshore area of the Oyodo River, resulting in the entrainment of the cold seawater into coastal waters from deep water. The oceanographic condition in relation to the continuous low SST could be favorable for local recruitment of glass eels.  相似文献   

Functional insulin‐like factor 3 (INSL3) hormone‐receptor system in the testes and spermatozoa of domestic ruminants and its potential as a predictor of sire fertility          下载免费PDF全文

Ali M. Pitia  Kyoko Uchiyama  Hiroaki Sano  Masashi Kinukawa  Yoshiaki Minato  Hiroshi Sasada  Tetsuya Kohsaka 《Animal Science Journal》2017,88(4):678-690

Insulin‐like factor 3 (INSL3) is essential for fetal testis descent, and has been implicated in the testicular and sperm functions in adult males; however, similar functions in domestic ruminants remain largely unknown. This study investigated the functional INSL3 hormone‐receptor system in adult ruminant testes and spermatozoa, and explored its potential to diagnose the fertility of sires. Testes and spermatozoa were obtained from fertile bulls, rams and he‐goats, whereas subfertile testes and spermatozoa were obtained only from bulls. As expected, INSL3 was visualized in Leydig cells, while we clearly demonstrated that the functional receptor, relaxin family peptide receptor 2 (RXFP2), enabling INSL3 to bind was identified in testicular germ cells and in the sperm equatorial segment of bulls, rams and he‐goats. In comparison to fertile bulls, the percentage of INSL3‐ and RXFP2‐expressing cells and their expression levels per cell were significantly reduced in the testes of subfertile bulls. In addition, the population of INSL3‐binding spermatozoa was also significantly reduced in the semen of subfertile bulls. These results provide evidence for a functional INSL3 hormone‐receptor system operating in ruminant testes and spermatozoa, and its potential to predict subfertility in sires.  相似文献   

Genetic diversity of the `peruvianum-complex' (Lycopersicon peruvianum (L.) Mill. and L. chilense Dun.) revealed by RAPD analysis     

Hiroaki Egashira  Hiroyuki Ishihara  Tadashi Takashina  Shigeru Imanishi 《Euphytica》2000,116(1):23-31

Two lines of hexaploid wheat were crossed and the basic generations of parent, F1, F2 and back-cross were sown in a controlled-environment chamber. FreshF1 and back-cross grains were generated, so the material could be handled either as the standard set of basic generations on a whole-plant basis, or as an extended set on an embryo or endosperm basis. The experiment was repeated. Mature grains were harvested and the starch particle size distribution was analysed in 3284 grains from 111 plants. Means and variances were partitioned into additive, dominance and interaction components. Grains from cross-pollinations had B-granule contents between parental values, rather than of the maternal parent, indicating an involvement of the grain genotype. Quantitative models based on endosperm genotype gave a better fit to the data than those based on embryo genotype. The difference in starch B-granule content between the parents was largely due to additive genes. Dominant genes were also indicated, with the first dose in the triploid endosperm having a large effect while the second dose had little or none. Non-allelic interactions were significant in the second experiment where the use of more types of backcross made them more detectable. There were also small and significant residual effects of the maternal plant in the first experiment, attributed to the vigour of the F1 mother plant and to the cytoplasm of Sunco. Narrow-sense heritability was low, between 0.05and 0.18 depending on the generation. Transgressive segregation was not found, suggesting that all alleles tending to increase the B-granule content were found in the Sunco parent and none in ME71. There was also no detectable heterosis in this character. The results show that breeding and selection for a low B-granule content should be possible but a further reduction will require new and complementary genes. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Development of a technique to estimate the horizontal distribution of lit fishing vessels in the East China Sea using satellite luminescence     

Saito  Rui  Sasaki  Hiroaki  Yamada  Haruya  Hiroe  Yutaka  Inagake  Denzo  Saito  Tsutomu 《Fisheries Science》2020,86(1):13-25

Fisheries Science - The East China Sea is a semi-enclosed sea, surrounded by Japan, China, South Korea and Taiwan, and is continuously influenced by lit fishing vessels overexploiting fishery...  相似文献   

Environmental characteristics of spawning and nursery grounds of Japanese sardine and mackerels in the Kuroshio and Kuroshio Extension area     

Sayaka Sogawa  Kiyotaka Hidaka  Yasuhiro Kamimura  Masanori Takahashi  Hiroaki Saito  Yuji Okazaki  Yugo Shimizu  Takashi Setou 《Fisheries Oceanography》2019,28(4):454-467

The sustainable use of marine resources requires understanding the surrounding ecosystem and elucidating mechanisms of variation. However, we still lack a comprehensive understanding of environmental variation in the spawning and nursery grounds of important fisheries species Japanese sardine (Sardinops melanostictus) and mackerels (Scomber japonicus and Scomber australasicus) in the northwest Pacific. Here, we investigate detailed physical, chemical, and biological environment variations in the spawning and nursery grounds along the Kuroshio and Kuroshio Extension area from intensive investigation in spawning season (April) of 2013. We found similar water mass property and copepod community in the egg‐rich Kuroshio area and the larvae‐rich downstream Kuroshio Extension area, indicating environmental variability is small during transportation and development processes. The egg‐rich northern Izu Islands region showed high copepod abundance, although low nutrient and chlorophyll concentrations were observed. Eggs were scarce or absent in the second survey 10 days after abundant eggs were observed in the region, along with differences in water property and copepod community. This indicates that not only the location but also the specific water characteristic and copepod community are a determining factor for spawning. Indicator communities of copepod found in our study (indicator community of transportation process from spawning ground, of non‐spawning ground, and of reproductive area in the Kuroshio Extension area) would be a key factor for recruitment prediction.  相似文献   

Evaluation from otolith Sr stable isotope ratios of possible juvenile growth areas of Japanese eels collected from the West Mariana Ridge spawning area     

Otake  Tsuguo  Amano  Yosuke  Shirai  Kotaro  Mochioka  Noritaka  Takahashi  Toshiro  Chow  Seinen  Kurogi  Hiroaki  Dou  Shouzeng  Yamaguchi  Asuka  Tsukamoto  Katsumi 《Fisheries Science》2019,85(3):483-493

Fisheries Science - The widely distributed East Asian Japanese eel Anguilla japonica constitutes a single genetically homogeneous population with a single spawning area near the West Mariana Ridge....  相似文献   

Difference in the stable nitrogen isotope ratio of Sargassum piluliferum (Phaeophyceae: Fucales) associated with fish and pearl oyster aquaculture facilities     

Hiroaki Matsuo  Nobuyuki Matsuka  Koji Omori  Yoshitsugu Koizumi  Ichiro Takeuchi 《Fisheries Science》2010,76(1):147-153

In order to estimate the nitrogen loading from fish aquaculture facilities, we studied the nitrogen and carbon stable isotope ratios (δ¹⁵N and δ¹³C, respectively) in the brown macroalga Sargassum piluliferum and small amphipod crustaceans Caprella spp., both of which are lower trophic level biota found at fish and pearl oyster aquaculture facilities situated along the eastern coast of the Uwa Sea, Japan. This coastal region is one of the least populated areas along the Japanese coast. The mean concentrations of chlorophyll a, dissolved inorganic nitrogen, dissolved inorganic phosphate, and dissolved silicate-Si were 1.5- to 2-fold higher in samples from the fish aquaculture facilities than in those from the pearl oyster aquaculture facilities, indicating that the fish aquaculture facilities were associated with nitrogen loading. The δ¹⁵N abundance level in S. piluliferum collected from the fish aquaculture facilities was significantly higher (1.3‰) than that in macroalga collected at the pearl oyster aquaculture facilities, whereas that in Caprella spp., primary consumers, was only slightly higher (0.3‰). The feeding style of Caprella spp., which depends on suspended particulate organic matter and attached microalgae, is considered to the primary causal factor for the lack of a significant difference in δ¹⁵N abundance level between the two types of aquaculture facilities. Based on these results, we conclude that S. piluliferum found in close proximity of aquaculture facilities is a suitable organism for monitoring nitrogen loading from fish aquaculture facilities, through the analysis of δ¹⁵N.  相似文献   

Collection,preservation and distribution of Oryza genetic resources by the National Bioresource Project RICE (NBRP-RICE)     

Yutaka Sato  Katsutoshi Tsuda  Yoshiyuki Yamagata  Hiroaki Matsusaka  Hiromi Kajiya-Kanegae  Yuri Yoshida  Ayumi Agata  Kim Nhung Ta  Sae Shimizu-Sato  Toshiya Suzuki  Misuzu Nosaka-Takahashi  Takahiko Kubo  Shoko Kawamoto  Ken-Ichi Nonomura  Hideshi Yasui  Toshihiro Kumamaru 《Breeding Science》2021,71(3):291

Biological resources are the basic infrastructure of bioscience research. Rice (Oryza sativa L.) is a good experimental model for research in cereal crops and monocots and includes important genetic materials used in breeding. The availability of genetic materials, including mutants, is important for rice research. In addition, Oryza species are attractive to researchers for both finding useful genes for breeding and for understanding the mechanism of genome evolution that enables wild plants to adapt to their own habitats. NBRP-RICE contributes to rice research by promoting the usage of genetic materials, especially wild Oryza accessions and mutant lines. Our activity includes collection, preservation and distribution of those materials and the provision of basic information on them, such as morphological and physiological traits and genomic information. In this review paper, we introduce the activities of NBRP-RICE and our database, Oryzabase, which facilitates the access to NBRP-RICE resources and their genomic sequences as well as the current situation of wild Oryza genome sequencing efforts by NBRP-RICE and other institutes.  相似文献   

Local administration of Neurokinin B in the arcuate nucleus accelerates the neural activity of the GnRH pulse generator in goats     

Yoshihiro WAKABAYASHI  Hiroaki OKAMURA  Takashi YAMAMURA 《The Journal of reproduction and development》2021,67(6):352

Kisspeptin neurons in the arcuate nucleus (ARC), which co-express neurokinin B (NKB) and dynorphin A, are termed KNDy neurons. These neurons are candidates for the intrinsic gonadotropin-releasing hormone (GnRH) pulse generator. The central and peripheral administration of NKB or its receptor (NK3R) agonist evokes GnRH pulse generator activity and the subsequent pulsatile GnRH/luteinizing hormone (LH) secretion. However, the mechanism responsible for neural activation of the GnRH pulse generator in goats is unclear. We conducted electrophysiological and histochemical experiments to test the hypothesis that KNDy neurons receive NKB and that the signal is transmitted bilaterally to a population of KNDy neurons. Bilateral electrodes aimed at a cluster of KNDy neurons were inserted into the ovariectomized goat ARC. We observed the GnRH pulse generator activity, represented by characteristic increases in multiple-unit activity (MUA volleys). The unilateral administration of NKB or vehicle in the close vicinity of KNDy neurons under simultaneous MUA recording from both sides revealed that only NKB evoked MUA volley(s) immediately after administration. The timing of the MUA volley(s) evoked on the ipsilateral side was synchronized to that on the contralateral side. The double-labeled ISH for KISS1 and TACR3, which encode kisspeptin and NK3R, respectively, revealed that most KNDy neurons co-expressed TACR3. Therefore, NKB could directly stimulate KNDy neurons, following which the stimulatory signal is immediately transmitted to the entire population of KNDy neurons via connection with their fibers. This mechanism helps synchronize burst activity among KNDy neurons, thereby generating neural signals that govern pulsatile GnRH secretion.  相似文献   

Diffusion tensor imaging-based quantitative analysis of the spinal cord in Pembroke Welsh Corgis with degenerative myelopathy     

Eiji NAITO  Kohei NAKATA  Hiroki SAKAI  Osamu YAMATO  Md Shafiqul ISLAM  Sadatoshi MAEDA  Hiroaki KAMISHINA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2022,84(2):199

Canine degenerative myelopathy (DM) is a progressive neurodegenerative disease of the spinal cord. The diagnosis is based on the observation of clinical signs, genetic testing, and exclusion of other spinal cord diseases, and a definitive diagnosis of DM can only be confirmed by postmortem histopathological findings. The aim of this study was to investigate the diagnostic ability of diffusion tensor imaging (DTI) for DM. Eight DM-affected Pembroke Welsh Corgis, thirteen dogs with thoracolumbar intervertebral disk herniation (IVDH), and six healthy control dogs were included. All dogs were scanned using a 3.0-T MRI system. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values were calculated for each intervertebral disk level slice between T8–T9 and L2–L3 intervertebral disk levels, and the entire area of the thoracolumbar spinal cord between T8–T9 and L2–L3 intervertebral disk levels (T8–L3 region). The ADC and FA values of the T8–L3 region were significantly lower in the DM group than in the IVDH group. The ADC values for the T8–L3 region had a moderate negative correlation with clinical duration (r_s= −0.723, P=0.043); however, the FA values of other intervertebral disk levels and T8–L3 region had no correlation with clinical durations. The measurement of DTI indices can be used to quantitatively assess neurodegeneration and may have diagnostic value for DM. In particular, the ADC value of the T8–L3 region may aid in making a non-invasive premortem diagnosis of DM.  相似文献