Net depth response of a depth-controllable (towed) gillnet for fish sampling     

Daisuke Shiode  Yasuzumi Fujimori  Fuxiang Hu  Susumu Shimizu  Teisuke Miura 《Fisheries Science》2001,67(1):110-117

SUMMARY: Flume-tank experiments were performed to examine the depth response of a new type of depth-controlled gillnet. Variations of net depth were investigated as the warp was paid out and wound up for different changes of warp length, main sinker weights, and winch speeds. In most experiments, when the warp finished paying out, the net continued to descend and then ascended slightly to an equilibrium depth (overshoot phenomenon). The overshoot distance was nearly constant when the warp was wound up and increased linearly with increasing winch speed when the warp was paid out. An increase in winch speed reduced net settling time, which converged on a constant value for both paying out and winding up.  相似文献   

Powdery Mildew of Prairie Gentian: Characteristics,Molecular Phylogeny and Pathogenicity   总被引：3，自引：0，他引：3  

OKAMOTO  Jun  LIMKAISANG  Saranya  NOJIMA  Hidenobu  TAKAMATSU  Susumu 《Journal of General Plant Pathology》2002,68(3):200-207

In March 1999, we found prairie gentian (Eustoma grandiflorum) infected with powdery mildew in a greenhouse in Oita Prefecture, Japan. Morphological observation revealed that the causal fungus belongs to the mitosporic genus Oidium subgenus Pseudoidium [teleomorph: Erysiphe sensu Braun and Takamatsu (2000)]. Precise taxonomic position of the fungus, however, is uncertain due to lack of the perfect stage. We determined the nucleotide sequence of the rDNA ITS region of the fungus. Comparison of the sequence with those obtained from DNA databases of this fungal group revealed that the sequence is identical to those of powdery mildews from garden four-o'clock (Mirabilis jalapa) and broad bean (Vicia faba). Inoculation of an isolate from garden four-o'clock caused mildew on prairie gentian and broad bean, suggesting that the prairie gentian mildew originates from garden four-o'clock or broad bean. Molecular phylogenetic analysis indicated a close relationship of this fungus to Erysiphe baeumleri on Vicia spp. and E. trifolii on Trifolium pratense. From these results, we propose that prairie gentian mildew diverged from a Fabaceae-parasitic ancestor. Received 14 March 2002/ Accepted in revised form 28 May 2002  相似文献   

Simultaneous detection of multiple mycotoxins in broiler feeds using a liquid chromatography tandem-mass spectrometry     

Jutamart KONGKAPAN  Saranya POAPOLATHEP  Supaporn ISARIYODOM  Susumu KUMAGAI  Amnart POAPOLATHEP 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2016,78(2):259-264

Mycotoxins are secondary fungal metabolites that are typically present in grain and feed ingredients used for animal feeds. An analytical method using LC-ESI-MS/MS was developed to quantify nine mycotoxins, consisting of aflatoxin B₁ (AFB₁), AFB₂, AFG₁, AFG₂, T-2 toxin, deoxynivalenol (DON), nivalenol (NIV), zearalenone (ZEA) and ochratoxin A (OTA) in broiler feeds. In total, 100 samples of broiler feeds were collected from poultry farms in Central Thailand. The survey found that AFB₁ and ZEA were the most prevalent mycotoxins in the feed samples at percentages of 93% and 63%, respectively. The limit of detections (LODs) of investigated mycotoxins was 0.20–0.78 ng/g. AFB₂, DON, AFG₁, NIV and T-2 toxin were also detectable at low contamination levels with percentages of 20%, 9%, 7%, 5% and 1%, respectively, whereas OTA and AFG₂ were not detected in any of the feed samples. These results suggest that there is a very low level of risk of the exposure to mycotoxins in feeds obtained from broiler farms in Central Thailand.  相似文献   

Identification of bovine serum albumin as an IgE-reactive beef component in a dog with food hypersensitivity against beef     

Ohmori K  Masuda K  Kawarai S  Yasuda N  Sakaguchi M  Tsujimoto H 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2007,69(8):865-867

IgE-reactive beef components were examined by an immunoblot analysis using a serum from a dog with food hypersensitivity against beef. The immunoblot analysis revealed a distinct band at approximately 66 kDa and a faint band at approximately 50 kDa. The immunoblot analysis for serum IgE reactivity to bovine serum albumin (BSA) also revealed a positive band at 66 kDa. Serum IgE reactivity to the 66-kDa protein of beef was diminished by pre-incubating the serum sample with BSA. Furthermore, a positive reaction to BSA was detected in intradermal testing in the dog. These results clearly indicated that BSA was an IgE-reactive beef component in the dog with food hypersensitivity against beef.  相似文献   

Enhancement of antigen-specific immunoglobulin G production in mice by co-administration of L-cystine and L-theanine   总被引：2，自引：0，他引：2  

Kurihara S  Shibahara S  Arisaka H  Akiyama Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2007,69(12):1263-1270

Supplementation with both cystine and glutamic acid increases the synthesis of glutathione (GSH), which has a marked effect on immune cell function, as compared with supplementation with either amino acid alone in human macrophages in vitro. As dietary glutamic acid is metabolized during intestinal transport, oral administration of L-theanine (gamma-glutamylethylamide), which is metabolized to glutamic acid mainly in the liver, may act as a glutamic acid donor in vivo. The present study was performed to investigate the effects of oral administration of L-cystine and/or L-theanine on GSH levels and immune responses. Co-administration of L-cystine (200 mg/kg) and L-theanine (80 mg/kg) for 11 days before immunization significantly increased the levels of total GSH in the liver 6 hr after immunization as compared with the levels in control mice. To examine the effects of administration of L-cystine and/or L-theanine on the balance of T helper (Th) 1/Th2 cell responses, the serum ratios of the Th1 cytokine, interferon (IFN)-gamma, and the Th2 cytokine, interleukin IL-10, were investigated. At 24 hr after immunization, co-administration significantly increased the IL-10/IFN-gamma ratio compared with the ratios of the control and single-administration mice. Furthermore, co-administration before primary immunization significantly enhanced serum antigen-specific IgG levels. Taken together, these findings suggest that co-administration of L-cystine and L-theanine enhances antigen-specific IgG production partly through augmentation of GSH levels and Th2-mediated responses.  相似文献   

Identification of oyster-derived hypotensive peptide acting as angiotensin-I-converting enzyme inhibitor     

Kazuhiro Shiozaki  Momo Shiozaki  Junko Masuda  Akiko Yamauchi  Shuichi Ohwada  Toshiki Nakano  Toshiyasu Yamaguchi  Tadao Saito  Koji Muramoto  Minoru Sato 《Fisheries Science》2010,76(5):865-872

Angiotensin-I-converting enzyme (ACE) plays a crucial role in the crisis of hypertension. Some peptides that originate from protease hydrolysates are known to suppress ACE activity in vitro and in vivo. Here, we investigated whether trypsin hydrolysate of oyster Crassostrea gigas showed hypotensive activity and ACE inhibition. The hydrolysate significantly suppressed systolic blood pressure and ACE activity in spontaneously hypertensive rats following a one-shot oral administration and a long-term feeding experiment lasting 9 weeks. Each hydrolysate from oyster tissue showed ACE inhibitory activity, indicating the hypotensive effect was due to synergism. One potent ACE inhibitory peptide, Asp-Leu-Thr-Asp-Tyr, was identified from the hydrolysate of the striate muscle, and the peptide exhibited hypotensive activity in vivo. Protease digestion analysis suggested that Asp-Tyr could be the real effector of this penta-peptide in vivo.  相似文献   

Underwater sound detection by cephalopod statocyst     

Kenzo Kaifu  Tomonari Akamatsu  Susumu Segawa 《Fisheries Science》2008,74(4):781-786

Abstract:   The cephalopod receptor of particle motion was identified. In a previous study, it was suggested that statocysts served this function, but there was no direct supporting evidence, and epidermal hair cells had not been conclusively ruled out. Experiments on Octopus ocellatus were conducted using respiratory activity as an indicator of sound perception. Intact animals clearly responded to 141-Hz particle motion at particle accelerations below 1.3 × 10⁻³ m/s², and the mean perception threshold at this frequency was approximately 6.0 × 10⁻⁴ m/s². Specimens in which the statoliths had been surgically removed did not show any response for accelerations up to 3.9 × 10⁻³ m/s² at 141 Hz, which was approximately 16 dB greater than the mean perception threshold at this frequency. Specimens that had undergone a control operation in which the statoliths remained intact showed positive responses at 2.8 × 10⁻³ m/s² for the same frequency stimulus. This indicates that the statocyst, which is morphologically similar to the inner ear system in fish, is responsible for the observed responses to particle motion in O. ocellatus . This is the first direct evidence that cephalopods detect kinetic sound components using statocysts.  相似文献   

Effects of Aeration, Alum Treatment, Liming, and Organic Matter Application on Phosphorus Exchange between Soil and Water in Aquaculture Ponds at Auburn, Alabama   总被引：4，自引：0，他引：4  

Kiyoshi  Masuda Claude E.  Boyd 《Journal of the World Aquaculture Society》1994,25(3):405-416

Application of readily-oxidizable organic substrate to laboratory soil-water systems and fish ponds caused anaerobic conditions in bottom soil and water, and concentrations of soluble reactive phosphorus (SRP) increased. Aeration of ponds increased total phosphorus (TP) concentrations by suspending soil particles in the water, but SRP concentrations declined because of increased oxy- genation of bottom water and soil, Alum [Al₂(SO₄)₃·14H₂O] treatment of ponds reduced SRP and TP concentrations in ponds, but the low concentration of alum used, 20 mg/L, had little residual effect on phosphorus concentration. Application of agricultural limestone at 0.2 kg/m² to ponds with soil pH of 5.5 and Ca²⁺ concentration of 5 mg/L did not affect SRP and TP concentration. Unless pond soils were anaerobic at their surfaces, a condition not acceptable in thermally-unstratified fish ponds, soils released little phosphorus to the water. Strong adsorption of phosphorus by soils in intensive ponds with feeding is beneficial, because removal of phosphorus by aerobic soils is a control on excessive phytoplankton growth. In fertilized ponds, phosphorus must be applied at frequent intervals to replace phosphorus removed from the water by soils.  相似文献   

Carbon and nitrogen stocks and their mineralization potentials are higher under organic than conventional farming practices in Japanese Andosols     

Valensi Kautsar  Keitaro Tawaraya  Susumu Yamada  Kazunobu Toriyama  Kazuhiko Kobayashi 《Soil Science and Plant Nutrition》2020,66(1):144-151

ABSTRACT

This study aimed at understanding whether and how long-term organic rice farming affects soil carbon (C) and nitrogen (N) stocks and their mineralization potentials in submerged rice paddies in Tochigi, Japan. An incubation experiment was carried out to assess the impacts of internal nutrient cycling after organic farming (OF) for 4–5 years (4OF), 8–9 years (8OF), and 12 years (12OF), compared with a conventional rice field (CF). Soil samples were collected at 0–15 cm and 15–20 cm in flooded rice fields after harvest in October 2013. pH and bulk density at 0–15 cm were significantly lower in 12OF fields than in CF fields (by 0.22 unit pH and 17.5%, respectively). Compared with CF, 12OF fields showed significant differences in soil organic carbon (SOC) and total nitrogen (TN), but 4OF and 8OF fields did not. In 8OF fields, the C decomposition (Co) and N mineralization (No) potentials were significantly higher (by 34.0% and 35.6%, respectively, at 0–15 cm, and by 67.1% and 24.5% at 15–20 cm) than in CF fields. Similarly, in 8OF fields at 0–15 cm, the Co:SOC and No:TN ratios were 19.8% and 23.2% higher, respectively, than in CF fields. Co, No, Co:SOC, and No:TN in 12OF fields were higher than those in CF fields, demonstrating the effects of prolonged organic rice farming. Additionally, in 12OF fields, C and N stocks were significantly higher (by 15.5% and 17.2%, respectively, at 0–15 cm, and by 4.8% and 12.1% at 15–20 cm) than in CF fields. Our findings suggest that long-term organic rice farming increases soil C and N stocks as well as C and N mineralization in Japanese Andosols.  相似文献   

Identification of the medicinal off-flavor compound formed from ascorbic acid and (E)-hex-2-enal     

Sakamaki K  Ishizaki S  Ohkubo Y  Tateno Y  Fujita A 《Journal of agricultural and food chemistry》2011,59(12):6667-6671

A test apple beverage made up of apple juice (20%), high-fructose corn syrup (11.5%), citric acid (0.43%), trisodium citrate (0.02%), apple-odor flavor (0.1%), and ascorbic acid (0.02%) was stored at 40 °C and then analyzed for the change of odor in the beverage. Although no thermoacidophilic bacteria (TAB) were detected, a medicinal off-flavor was perceived after the 8 weeks of storage. Model experiments on the ingredients of the test apple beverage revealed that the off-flavor compound had been formed by ascorbic acid and (E)-hex-2-enal. Synthesis and NMR (1H, 13C, HMQC, and HMBC) analyses identified the compound as 6-propylbenzofuran-7-ol. The odor quality, retention index (RI), and mass spectrum of synthetic 6-propylbenzofuran-7-ol were identical with those of the medicinal odor compound from the test apple beverage. Sensory evaluation revealed the recognition thresholds for medicinal odor were 31.4 ppb in water and 24.0 ppb in apple beverage, and the detection thresholds were 19.6 ppb in water and 8.6 ppb in apple beverage, respectively. The quantified concentration of 6-propylbenzofuran-7-ol formed in test apple beverage was 90 ppb, approximately. This concentration was well above the odor threshold, so it was concluded that the compound was the source of the medicinal off-flavor.  相似文献