Effects of thyroid hormone on gonadotropin-induced steroid production in medaka,Oryzias latipes,ovarian follicles

Blood and ovarian samples were collected at intervals of 4h prior to spawning time from medaka (Oryzias latipes) that were maturationally synchronized with artificial photoperiod (14h light: 10h dark). Plasma estradiol-17β (E₂) levels increased rapidly from 16h before spawning and peaked at 8h before spawning. Follicle-enclosed oocytes (ovarian follicles) at different stages of development were isolated from the ovaries and used to study the in vitro effects of thyroid hormone (triiodothyronine; T₃) on pregnant mare serum gonadotropin (GTH)-induced E₂ production. GTH at a concentration of 100 IU/ml stimulated E₂ production by ovarian follicles collected between 32 and 16h before spawning. At 32h before spawning, T₃ (5 ng/ml) administered along with GTH (100 IU/ml) resulted in a 3.5 fold increase in E₂ production, compared with GTH administered alone. These results suggest that T₃ can act on ovarian follicles directly to modulate GTH-stimulated E₂ production in the medaka.     

Growth hormone-like substance in the rotifer Brachionus plicatilis

ABSTRACT:   A growth hormone (GH)-like substance was extracted from the rotifer Brachionus plicatilis and subsequently purified by gel filtration and ion exchange chromatography. The GH-like substance had a molecular weight of approximately 28 kDa and had cross-reactivity with salmon GH antibody. In vivo bioassay showed a higher intrinsic rate of increase and net reproduction rate of B. plicatilis treated with the GH-like substance.     

Chemical Characteristics of Bottom Soils from Freshwater and Brackishwater Aquaculture Ponds

Soil chemical analyses were conducted on samples from 358 freshwater fish ponds and 346 brackishwater shrimp ponds. Freshwater ponds were located in Honduras, Rwanda, Bhutan, and the United States. Ponds in the United States were in Alabama, Georgia, Mississippi, Florida, and South Carolina. Brackishwater ponds were in Thailand, Ecuador, Philippines, and Venezuela. Soils of freshwater and brackishwater ponds did not differ greatly in average concentrations and concentration ranges for carbon, nitrogen, calcium, and pH. Concentrations of copper and barium tended to be higher in freshwater soils than in brackishwater ones. All other measured chemical constitutents tended to be more abundant in the soils of brackishwater ponds than in those of freshwater ponds. For the most part, ranges of pond soil chemical properties were similar to those of terrestrial soils, with freshwater pond soils resembling terrestrial soils from humid areas and brackishwater soils being similar in many respects to soils of arid regions. However, some brackishwater pond soils were highly acidic, acid-sulfate soils. Data were arranged into concentration categories (very low, low, medium, high, and very high) to facilitate comparisons of the present data set with other data on soil chemical properties for aquaculture ponds. All ponds included in the present study were used for aquaculture, showing that it is possible to rear fish and shrimp across an extremely wide range of soil chemical properties.     

Chromospheric anemone jets as evidence of ubiquitous reconnection

The heating of the solar chromosphere and corona is a long-standing puzzle in solar physics. Hinode observations show the ubiquitous presence of chromospheric anemone jets outside sunspots in active regions. They are typically 3 to 7 arc seconds = 2000 to 5000 kilometers long and 0.2 to 0.4 arc second = 150 to 300 kilometers wide, and their velocity is 10 to 20 kilometers per second. These small jets have an inverted Y-shape, similar to the shape of x-ray anemone jets in the corona. These features imply that magnetic reconnection similar to that in the corona is occurring at a much smaller spatial scale throughout the chromosphere and suggest that the heating of the solar chromosphere and corona may be related to small-scale ubiquitous reconnection.     

Self-feeding activity of a pleuronectiform fish, the barfin flounder

The self-feeding activity of the barfin flounder (Verasper moseri) was examined under natural photoperiod and temperature. The experiment, carried out over 12 weeks from September to December, involved tagged fish (mean body weight: 371 g) reared in three 1000-l tanks (3 or 5 fish per tank) with a self-feeder device. The sensor comprised a switch and trigger string with a bead. Self-feeding activity was recorded in all tanks from day 1. The fish fed mostly at night. Strong positive correlations were observed between the number of daily feeder activations and water temperature/photoperiod, and all fish grew during the experiment. These results demonstrate that barfin flounder can operate self-feeding systems and it is suggested that self-feeding activity is influenced by photoperiod and water temperature.     

Simple Measurement of 4,4’-bis(2-sulfostyryl)-biphenyl in River Water by Fluorescence Analysis and Its Application as an Indicator of Domestic Wastewater Contamination

A characteristic peak of fluorescent whitening agents (FWAs) was detected by fluorescence excitation spectrum (FES) measurement of river water samples. The main causative chemical was 4,4’-bis(2-sulfostyryl)-biphenyl (DSBP), which is commonly added to household detergents in Japan. As the fluorescence of DSBP overlaps with that of fulvic-like organic matter in the spectral fluorescent signatures, DSBP concentration was determined by the newly proposed calculation method, which uses fluorescence intensity at three excitation wavelengths of 320, 345 and 360 nm at emission wavelength of 430 nm for baseline correction. The concentration of DSBP calculated using this method showed strong correlation (correlation coefficient: r = 0.992) with that obtained by high-performance liquid chromatography analysis. The concentrations of DSBP detected in river water samples were 0.28 to 1.84 μg l^?1, with high concentrations observed at the stations with relatively high flow rates of upstream sources of treated domestic wastewater and untreated gray water (domestic wastewater excluding flush toilet wastewater). It was proved that the concentration of DSBP in river water is useful for giving rough estimation of the magnitude of domestic wastewater contamination in river water.     

Caffeoylsophorose in a red vinegar produced through fermentation with purple sweetpotato

Recently, a new red vinegar has been developed via fermentation with the storage root of purple-fleshed sweetpotato, Ipomoea batatas L. cv. Ayamurasaki. The red vinegar had a higher antioxidative activity than white or black vinegars. The red vinegar contained some new components possibly derived from the original purple sweetpotato. A major component was isolated using preparative HPLC, and the chemical structure was determined to be 6-O-(E)-caffeoyl-(2-O-beta-d-glucopyranosyl)-alpha-d-glucopyranose (caffeoylsophorose) by MS and NMR. Because the caffeoylsophorose showed a high antioxidative activity, it plays an important functional role in red vinegar as do anthocyanins and other components. Examination of the mechanism of formation is now in progress.     

Molecular detection of filarial nematode parasites in Japanese black bears (Ursus thibetanus japonicus) from Iwate Prefecture, Japan

This study aimed to detect filarial parasites in blood samples of Japanese black bears (Ursus thibetanus japonicus) collected from Iwate Prefecture, Japan. Positive amplicons were obtained from 26 out of 30 samples by nested PCR targeting 18S ribosomal RNA gene and first internal transcribed spacer regions. DNA sequences of Mansonella sp. close to M. ozzardi and Dirofilaria sp. were detected for eight and 11 positive amplicons, respectively. Co-infection was detected for the remaining seven amplicons. Dirofilaria sp. was identified as D. ursi by further genetic analysis of 5S ribosomal RNA gene sequence. The results of this study will contribute to further investigations of Japanese black bears for monitoring their risk as a reservoir of possible zoonotic filarial parasites.