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   

Paralytic shellfish poisoning toxin analysis of the genus <Emphasis Type="Italic">Alexandrium</Emphasis> (Dinophyceae) occurring in Korean coastal waters     

Choong?-Jae?KimEmail author  Chang?-Hoon?Kim  Yoshihiko?Sako 《Fisheries Science》2005,71(1):1-11

ABSTRACT:   Paralytic shellfish poisoning (PSP) toxins produced by Alexandrium isolates from Korea were analyzed by high-pressure liquid chromography. Species designation of the regional isolates was determined by morphological criteria and ribotyping inferred from sequences of the 28S rDNA D1-D2 region. Toxin analysis performed at the exponential growth phase, revealed that the two strains of A. fraterculus were non-toxic, while the strains of A. tamarense and A. catenella were toxic. Toxic isolates DPC7 and DPC8 of A. catenella produced GTX1, 2, 3, 4, 5, dcGTX2, 3, C1, 2, neoSTX and STX with trace or non-detectable levels of C3 and C4, while isolates UL7, KDW981, SJW97043, SJW97046, KJC97111 and KJC97112 of A. tamarense produced GTX1, 2, 3, 4, dcGTX3, C1, 2, neoSTX with trace or non-detectable levels of C3, 4, dcSTX and STX, and no GTX5 and dcGTX2. The major toxins produced by A. catenella were C1 +2, and those of A. tamarense were C1 +2 and GTX4 in most of the isolates. A. tamarense strains other than SJW97046 produced a relatively high proportion of carbamate toxins, reflecting the high toxicity scores of shellfish intoxication in sampled coastal areas. Two representative toxic isolates, A. tamarense SJW97043 and A. catenella DPC7, were cultured for 30 days in batch mode and subjected to toxin analysis at 5-day intervals. Comparison of toxin productivity in terms of total toxin content, toxin components, and their variations with culture age revealed marked differences between the two strains.  相似文献   

Purified Culture Systems for Bovine Oviductal Stromal Cells     

Yuki YAMAMOTO  Yoshihiko KOBAYASHI  Kiyoshi OKUDA 《The Journal of reproduction and development》2014,60(1):73-77

Isolated stromal cells from the ampullary and isthmic parts of bovine oviductal tissues were cultured in monolayer and spheroid (cell aggregate) systems. Prostaglandin F2α (PGF) plays a crucial role in oviductal contraction and is produced by oviductal epithelial cells in cattle. Since stromal cells of many organs produce PGF, PGF production by bovine oviductal stromal cells was investigated. After PGF synthesis was confirmed, the utility of isolation and culture methods for oviductal stromal cells was evaluated by PGF production in the present study. The homogeneity of the cells was > 99%. PGF production of the cells was increased by tumor necrosis factor-α. The stromal cells aggregated and formed a spheroid by the treatments with several reagents. PGF production was higher in the spheroid culture than in the monolayer culture. The isolation and culture methods described here will facilitate studies of the physiological function of bovine oviductal stromal cells.  相似文献   

Development of a quantification assay for the cysts of the toxic dinoflagellate <Emphasis Type="Italic">Alexandrium tamarense</Emphasis> using real-time polymerase chain reaction   总被引：1，自引：0，他引：1  

Ryoma?KamikawaEmail author  Shoko?Hosoi-Tanabe  Satoshi?Nagai  Shigeru?Itakura  Yoshihiko?Sako 《Fisheries Science》2005,71(5):987-991

ABSTRACT:   The cysts of toxic dinoflagellate Alexandrium tamarense are the seed population for the bloom responsible for paralytic shellfish poisoning (PSP). However, it is impossible to identify the Alexandrium spp. cyst on the basis of morphological features. In this study, we prepared A. tamarense cysts by sexual conjugation in laboratory conditions and developed an efficient DNA extraction method for polymerase chain reaction (PCR) assay. Using the A. tamarense cysts, we established the identification and quantification method showing the species specificity and the high sensistivity for A. tamarense cysts using real-time PCR. This assay was also able to detect and quantify the A. tamarense cysts accurately when mixed with excess cysts of A. catenella (Whedon and Kofoid) Balech prepared by conjugation experiment.  相似文献   

Development and application of fluorescence in situ hybridization (FISH) method for simple and rapid identification of the toxic dinoflagellates Alexandrium tamarense and Alexandrium catenella in cultured and natural seawater   总被引：2，自引：0，他引：2  

Shoko Hosoi-Tanabe  Yoshihiko Sako 《Fisheries Science》2006,72(1):77-82

ABSTRACT:   The toxic dinoflagellates Alexandrium tamarense (Lebour) Balech and A. catenella (Whedon and Kofoid) Balech produce potent neurotoxins, such as saxitoxin and gonyautoxin and have been mainly responsible for paralytic shellfish poisoning (PSP) in Japan. To prevent a negative effect on the fishery industry, it is necessary to identify these toxic species precisely and rapidly before and during the bloom. In this paper, a rapid and simple protocol of a fluorescence in situ hybridization (FISH) method using ribosomal RNA (rRNA)-targeted probes has been established for identifying the cultured strains and natural cells of A. tamarense and A. catenella . Using the FISH method established in this study, it was possible to identify these toxic species species-specifically and rapidly, within 30 min. The procedure of detection constituted three steps: (i) fixation/dehydration; (ii) hybridization; and (iii) washing; this made the identification simple. Moreover, this method did not require either special techniques or equipment, and the cost for detection was low. The specificity, rapidity, and simplicity of the developed method suggest that it might be useful for routine monitoring of these toxic microalgae.  相似文献   

Activities of mesencephalic nucleus neurons during fictive swimming of the carp Cyprinus carpio     

Yoshihiko  BABA  Yasuyuki  KAKE  Masayuki  YOSHIDA  Kazumasa  UEMATSU 《Fisheries Science》2003,69(3):581-588

ABSTRACT:   Fish swim by undulatory contractions of the axial trunk musculature. It has been presumed that a descending signal from the brainstem activates central pattern generators in the spinal cord to make the swimming rhythm. In the carp the electrical or chemical stimulation of a mesencephalic nucleus, the nucleus fasciculi longitudinalis medialis (Nflm), could initiate swimming. However, it has not been established what signals originate from the Nflm in order to make the fish swim. The activity of the Nflm neurons was therefore examined electrophysiologically during fictive swimming in paralyzed carp. Three types of neuronal activities closely related to the swimming rhythms were obtained. The first type was a continuous tonic firing throughout an episode of fictive swimming. Neurons involved in this tonic activity may project to the spinal cord and contribute to the activation of spinal neurons to initiate fish swimming. The second type was accompanied by continual phasic firings occurring in rhythm with the activity of spinal motoneurons. Supposing that the swimming rhythm originates in the spinal cord, the synchronous activity in the brain neurons may suggest that in the nucleus there is a relay neuron conveying the rhythm information from the cord to other neurons there or in the brain. The third type exhibited reduced firing rates during fictive swimming. It is possible that the neurons engaged in this activity may be inhibitory and suppress the activities of other neurons in the nucleus and spinal cord during rest or during decelerating swimming.  相似文献   

Antitumor activity of compounds isolated from leaves of Eriobotrya japonica   总被引：3，自引：0，他引：3  

Ito H  Kobayashi E  Li SH  Hatano T  Sugita D  Kubo N  Shimura S  Itoh Y  Tokuda H  Nishino H  Yoshida T 《Journal of agricultural and food chemistry》2002,50(8):2400-2403

In a search for possible antitumor agents from natural sources, megastigmane glycosides and polyphenolic constituents isolated from the leaves of Eriobotrya japonica (Rosaceae) were found to inhibit the 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced activation of Epstein-Barr virus early antigen in Raji cells. Roseoside and procyanidin B-2 were among the active compounds found in an in vitro assay; these compounds were further assessed for antitumor activity in vivo in a two-stage carcinogenesis assay on mouse skin. Roseoside significantly delayed carcinogenesis induced by peroxynitrite (initiator) and TPA (promoter), and its potency was comparable to that of a green tea polyphenol, (-)-epigallocatechin 3-O-gallate, in the same assay.  相似文献   

Validation of a food-frequency questionnaire for cohort studies in rural Japan     

Ogawa K  Tsubono Y  Nishino Y  Watanabe Y  Ohkubo T  Watanabe T  Nakatsuka H  Takahashi N  Kawamura M  Tsuji I  Hisamichi S 《Public health nutrition》2003,6(2):147-157

  相似文献   

Aureusidin synthase: a polyphenol oxidase homolog responsible for flower coloration   总被引：1，自引：0，他引：1  

Nakayama T  Yonekura-Sakakibara K  Sato T  Kikuchi S  Fukui Y  Fukuchi-Mizutani M  Ueda T  Nakao M  Tanaka Y  Kusumi T  Nishino T 《Science (New York, N.Y.)》2000,290(5494):1163-1166

Aurones are plant flavonoids that provide yellow color to the flowers of some popular ornamental plants, such as snapdragon and cosmos. In this study, we have identified an enzyme responsible for the synthesis of aurone from chalcones in the yellow snapdragon flower. The enzyme (aureusidin synthase) is a 39-kilodalton, copper-containing glycoprotein catalyzing the hydroxylation and/or oxidative cyclization of the precursor chalcones, 2',4',6',4-tetrahydroxychalcone and 2',4',6',3,4-pentahydroxychalcone. The complementary DNA encoding aureusidin synthase is expressed in the petals of aurone-containing varieties. DNA sequence analysis revealed that aureusidin synthase belongs to the plant polyphenol oxidase family, providing an unequivocal example of the function of the polyphenol oxidase homolog in plants, i.e., flower coloration.  相似文献   

Extended glucuronidation is another major path of cyanidin 3-O-beta-D-glucopyranoside metabolism in rats     

Ichiyanagi T  Shida Y  Rahman MM  Hatano Y  Konishi T 《Journal of agricultural and food chemistry》2005,53(18):7312-7319

We previously determined that five rather hydrophobic metabolites appeared in blood plasma after oral administration of cyanidin 3-O-beta-D-glucopyranoside, but a group of hydrophilic metabolites still remained unidentified. In the present study, 12 hydrophilic metabolites found were collected from urine and plasma samples by high-performance liquid chromatography (HPLC) and then analyzed by tandem MS spectrometry. From the MS spectra, four metabolites out of 12 were assigned as glucuronides of cyanidin 3-O-beta-D-glucopyranoside and six out of 12 were glucuronides of the primary metabolites of cyanidin 3-O-beta-D-glucopyranoside (O-methyl cyanidin 3-O-beta-D-glucopyranoside). Extended glucuronides of cyanidin 3-O-beta-D-glucopyranoside and O-methyl cyanidin 3-O-beta-D-glucopyranoside showed their maximum plasma concentrations at 15 and 60 min (or 30 min) after oral administration, respectively. Their maximum plasma concentrations ranged from 15 to 70 nM. From the profile of urinary-excreted anthocyanins after intravenous administration, it was deduced that extended glucuronides of cyanidin 3-O-beta-D-glucopyranoside and O-methyl cyanidin 3-O-beta-D-glucopyranoside were mainly produced in the liver rather than by intestinal flora. The area under the plasma concentration curve was 0.25 micromol min/L for extended glucuronides of cyanidin 3-O-beta-D-glucopyranoside and 0.14 micromol min/L for O-methyl cyanidin 3-O-beta-D-glucopyranoside, respectively, when evaluated as cyanidin 3-O-beta-D-glucopyranoside equivalent, indicating that extended glucuronidation is a critical pathway in cyanidin 3-O-beta-D-glucopyranoside metabolism in rats.  相似文献