Predation on glass eels of Japanese eel <Emphasis Type="Italic">Anguilla japonica</Emphasis> in the Tone River Estuary,Japan     

Yoichi Miyake  Aigo Takeshige  Hikaru Itakura  Hajime Itoh  Hiroaki Onda  Akira Yamaguchi  Akihito Yoneta  Kohma Arai  Yulina V. Hane  Shingo Kimura 《Fisheries Science》2018,84(6):1009-1014

Aquaculture of Japanese eel Anguilla japonica relies upon the natural recruitment of their glass eels (juveniles); however, predation that could influence glass eel recruitment remains unknown. In the present study, we aimed to elucidate the proportion of predation on A. japonica glass eels through stomach content analysis of predatory fishes collected in the estuary region of the Tone River system and its vicinity in Japan. Species of the predated glass eels were identified by DNA barcoding. A total of 270 predatory fishes of 15 taxa was collected over 2 years. The overall proportion of predation on glass eels, genetically identified as Japanese eel, was 0.7%, but this rose to 2.0% when data were limited to fishes caught during the peak months of glass eel recruitment. A glass eel was found in the stomach contents of a channel catfish Ictalurus punctatus, an invasive species in this river system, and a blackfin sea bass Lateolabrax latus. These fishes are therefore considered potential predators of A. japonica glass eels. However, as the proportion of predation was low, and the glass eels represented only small proportions of predator stomach contents, further investigation is needed for a better understanding of predation on A. japonica glass eels, and its effects on the early life stages of this endangered species.  相似文献   

Acetylcholinesterase activity, and neurofilament protein, and catecholamine synthesizing enzymes immunoreactivities in the mouse adrenal gland during postnatal development.     

K Iwasa  Y Oomori  H Tanaka 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1999,61(6):621-629

The present study showed the acetylcholinesterase (AChE) activity, and neurofilament protein (NFP), catecholamine-synthesizing enzymes, dopamine beta-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT) immunoreactivities in the mouse adrenal gland during postnatal development. From birth to postnatal-1-day, AChE activity was weakly and diffusely found in some medullary cells and in very few nerve fibers whereas strong NFP immunoreactivity was seen in a few ganglion cells and in remarkably numerous nerve fibers in the medulla. Almost all meduallary cells were reactive for both DBH and PNMT during this period. From postnatal-2- or -3-day to postnatal-1-week, strong AChE activity was observed in a few large ganglion cells, but the reaction was weak in clusters of chromaffin cells, and the number of strong AChE-active nerve fibers in the medulla was rapidly increased. From postnatal-2-day onwards, the number of NFP-immunoreactive nerve fibers in the medulla were remarkably numerous. Numerous chromaffin cells were reactive for both DBH and PNMT whereas some chromaffin cells were reactive for only DBH from postnatal-2-day onwards. These results suggest that drastic changes such as an increase of acetylcholine in the nerve fibers, differentiation of noradrenaline and adrenaline cells of the medulla may occur during this period. From postnatal-2-week to postnatal-3-week, weak AChE activity was seen in the clusters of several chromaffin cells and a few ganglion cells, and the number of AChE-active nerve fibers in the medulla was gradually increased. From postnatal-4-week to postnatal-8-week (adult), the distribution and frequency of AChE activity in the adrenal gland were similar to those at postnatal-3-week. In the adult, AChE activity was weakly seen in the clusters of several chromaffin cells showing noradrenaline fluorescence in the adrenal medulla. The noradrenaline cells were contacted by denser AChE-reactive nerve fibers than adrenaline cells. These results suggest that the development of cholinergic nervous system in the mouse adrenal medulla may be completed by postnatal-3-week.  相似文献   

Colocalization of gamma-aminobutyric acid immunoreactivity and acetylcholinesterase activity in nerve fibers of the mouse adrenal gland.     

K Iwasa  Y Oomori  H Tanaka 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1999,61(6):631-635

The present immunohistochemical and enzyme histochemical study showed gamma-aminobutyric acid (GABA) immunoreactivity and acetylcholinesterase (AChE) activity in the mouse adrenal gland. Weak GABA immunoreactivity was seen in clusters of chromaffin cells showing noradrenaline fluorescence. This finding suggests that both GABA and noradrenaline may be released from the granules of noradrenaline cells by adequate stimuli. GABA-immunoreactive varicose nerve fibers densely contacted adrenaline cells and large ganglion cells, but they were sparse in the periphery of clusters of noradrenaline cells. AChE activity was strong in a few large ganglion cells and weak in chromaffin cells showing noradrenaline fluorescence, and was found in numerous nerve bundles and fibers of the medulla. AChE-active nerve fibers more densely contacted noradrenaline cells than adrenaline cells. By using double labeling technique, numerous GABA-immunoreactive nerve fibers in the medulla were reactive for AChE in the same sections. These results suggest that both GABA and acetylcholine may be colocalized in the intra-adrenal nerve fibers and may have some secretory effects on the chromaffin cells.  相似文献   

Identification of overwintering vegetative cells of the bivalve-killing dinoflagellate <Emphasis Type="Italic">Heterocapsa circularisquama</Emphasis> in Uranouchi Inlet,Kochi Prefecture,Japan     

Tomotaka Shiraishi  Shingo Hiroishi  Seiya Taino  Tetsu Ishikawa  Yoshihiro Hayashi  Setsuko Sakamoto  Mineo Yamaguchi  Ichiro Imai 《Fisheries Science》2008,74(1):128-136

ABSTRACT:   Red tides of Heterocapsa circularisquama have led to serious damage of bivalve aquacultures in western coastal areas of Japan. To understand the whole picture regarding the ecology of this species, it is essential to clarify its overwintering mechanisms. In this study, the population dynamics of H. circularisquama were investigated from February 2004 to November 2005, and overwintering cells were identified for the first time in water columns of Uranouchi Inlet, Kochi Prefecture, Japan. Heterocapsa circularisquama cells were detected by the indirect fluorescent antibody technique using monoclonal antibodies that specifically recognize and react to this species. Vegetative cells were almost always detected from the first observation in February 2004 to November 2005 with temperatures of 10.5–30.6°C. During the period from winter to spring, this species survived in areas with a temperature higher than 10°C. The overwintering cells of H. circularisquama were isolated in March 2004, and identification was made via observation of the morphology and body scales of the cultured cells. These overwintering cells were identified as H. circularisquama and reacted to the monoclonal antibody. These results indicate that H. circularisquama can overwinter and survive throughout the year in a vegetative cell state in Uranouchi Inlet.  相似文献   

Characterization and expression of Saprospira cytoplasmic fibril protein (SCFP) gene from algicidal Saprospira spp. strains     

Takeshi Yoshikawa  Miyuki Nakahara  Ayano Tabata  Shingo Kokumai  Go Furusawa  Taizo Sakata 《Fisheries Science》2008,74(5):1109-1117

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Soil Adsorption of Urea II     

Shingo Mitsui  Hiroshi Takatoh 《Soil Science and Plant Nutrition》2013,59(3):19-26

Soils have generally been considered to adsorb little amounts of urea because it scarcely dissociates in water solution. A few works^1-3) have been reported on this problem. But it should be noticed that an electrostatic adsorption might not be the sole mechanism of soil adsorption of urea. In the previous paper⁴⁾ a correlation between equilibrium concentrations of urea in soil solutions and the amount of adsorbed urea was worked out, using Tanashi paddy soil of volcanic ash origin. An adsorption coefficient of Urea on the soil was calculated from the correlation and it was suggested that the soil possibly adsorbed considerable amounts of urea by a force which was weaker than the electrostatic force. together with experiments⁴⁾ using urea derivatives such as thiourea, methylurea or dimethylurea, it was concluded that the soil adsorption of Urea was possibly due to the formation of hydrogen bondings, principally arising from amino hydrogens and partly from carbonyl oxygen in a urea molecule.  相似文献   

Pharmacokinetics in plasma and alveolar regions of a healthy calf intramuscularly administered a single dose of orbifloxacin     

Tetsuro KURAMAE  Shingo ISHIKAWA  Aki KONO  Seiji HOBO 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2022,84(3):400

This study analyzed the pharmacokinetics of orbifloxacin (OBFX) in plasma, and its migration and retention in epithelial lining fluid (ELF) and alveolar cells within the bronchoalveolar lavage fluid (BALF). Four healthy calves received a single dose of OBFX (5.0 mg/kg) intramuscularly. Post-administration OBFX dynamics were in accordance with a non-compartment model, including the absorption phase. The maximum concentration (C_max) of plasma OBFX was 2.2 ± 0.1 μg/ml at 2.3 ± 0.5 hr post administration and gradually decreased to 0.3 ± 0.2 μg/ml at 24 hr following administration. The C_max of ELF OBFX was 9.3 ± 0.4 μg/ml at 3.0 ± 2.0 hr post administration and gradually decreased to 1.2 ± 0.1 μg/ml at 24 hr following administration. The C_max of alveolar cells OBFX was 9.3 ± 2.9 μg/ml at 4.0 hr post administration and gradually decreased to 1.1 ± 0.2 μg/ml at 24 hr following administration. The half-life of OBFX in plasma, ELF, and alveolar cells were 6.9 ± 2.2, 7.0 ± 0.6, and 7.8 ± 1.6 hr, respectively. The C_max and the area under the concentration-time curve for 0–24 hr with OBFX were significantly higher in ELF and alveolar cells than in plasma (P<0.05). These results suggest that OBFX is distributed and retained at high concentrations in ELF and alveolar cells at 24 hr following administration. Hence, a single intramuscular dose of OBFX (5.0 mg/kg) may be an effective therapeutic agent against pneumonia.  相似文献   

Considerations on diving patterns of bigeye tuna Thunnus obesus based on archival tag data     

Takayuki Matsumoto  Takashi Kitagawa  Shingo Kimura 《Fisheries Science》2013,79(1):39-46

Swimming depth and selected environmental factors were examined using 2764 days of archival tag data for 18 bigeye tuna Thunnus obesus (fork length at release 58.5 ± 7.2 cm) that were captured, tagged, and released into Japanese waters. Daytime swimming depth was deeper with increasing body length. The lowest temperature encountered was usually about 10 °C or slightly higher. A positive correlation between swimming depth and light intensity at the ocean surface was dominant for during both daytime and nighttime. Synchronicity of swimming depth with deep scattering layer (DSL) was observed, except around midday. Deep diving to depths exceeding 550 m was observed a mean of 0.30 dives/fish/day. Based on the classification and analyses of deep diving pattern and consideration of environmental data, deep diving was assumed to be undertaken for the purposes of foraging, predator avoidance, and exploration of bathymetry, as well as due to aberrant behavior. Occasionally, extremely deep diving events exceeding 1000 m (maximum 1616 m) were recorded. Bigeye tuna appear to have high visual acuity and tolerance of both low and wide temperature ranges, and low dissolved oxygen content. Thus, probably bigeye tuna swimming depth is primarily adjusted based on prey distribution.  相似文献   

Development of Singlet Oxygen Absorption Capacity (SOAC) Assay Method. 3. Measurements of the SOAC Values for Phenolic Antioxidants     

K Mukai  A Ouchi  S Takahashi  K Aizawa  T Inakuma  J Terao  S Nagaoka 《Journal of agricultural and food chemistry》2012,60(32):7905-7916

Measurements of the singlet oxygen ((1)O(2)) quenching rates (k(Q) (S)) and the relative singlet oxygen absortpion capacity (SOAC) values were performed for 16 phenolic antioxidants (tocopherol derivatives, ubiquinol-10, caffeic acids, and catechins) and vitamin C in ethanol/chloroform/D(2)O (50:50:1, v/v/v) solution at 35 °C. It has been clarified that the SOAC method is useful to evaluate the (1)O(2)-quenching activity of lipophilic and hydrophilic antioxidants having 5 orders of magnitude different rate constants from 1.38 × 10(10) M(-1) s(-1) for lycopene to 2.71 × 10(5) for ferulic acid. The logarithms of the k(Q) (S) and the SOAC values for phenolic antioxidants were found to correlate well with their peak oxidation potentials (E(p)); the antioxidants that have smaller E(p) values show higher reactivities. In previous works, measurements of the k(Q) (S) values for many phenolic antioxidants were performed in ethanol. Consequently, measurements of the k(Q) (S) and relative SOAC values were performed for eight carotenoids in ethanol to investigate the effect of solvent on the (1)O(2)-quenching rate. The k(Q) (S) values for phenolic antioxidants and carotenoids in ethanol were found to correlate linearly with the k(Q) (S) values in ethanol/chloroform/D(2)O solution with a gradient of 1.79, except for two catechins. As the relative rate constants (k(Q)(AO) (S)/k(Q)(α-Toc) (S)) of antioxidants (AO) are equal to the relative SOAC values, the SOAC values do not depend on the kinds of solvent used, if α-tocopherol is used as a standard compound. In fact, the SOAC values obtained for carotenoids in mixed solvent agreed well with the corresponding ones in ethanol.  相似文献   

Discovering the dominance of the non-native European eel in the upper reaches of the Tone River system,Japan     

Kohma Arai  Hikaru Itakura  Akihito Yoneta  Tatsuki Yoshinaga  Fumiaki Shirotori  Kenzo Kaifu  Shingo Kimura 《Fisheries Science》2017,83(5):735-742

To investigate the presence of non-native anguillid eels in Japanese waters, 141 eels were collected from seven sampling sites throughout the Tone River system. Genetic species identification showed an extraordinary dominance of the non-native European eel Anguilla anguilla in the uppermost site of the study area. Estimation of age from otoliths suggested that the European eels were introduced into the river in the 1990s, corresponding to previous reports from other Japanese water systems. Comparison of the von Bertalanffy growth curve parameters indicated that the European eels caught in the Tone River system appeared to have a similar or even higher growth rate than the same species in the original habitats in Europe. The long-term inhabitation and the normal development of European eels in Japanese waters suggest that regulations prohibiting the release of non-native eels and safeguards against accidental escape from culture ponds must be strictly maintained in order to ensure the conservation of the native Japanese eel.  相似文献