425 research outputs found
Ecological value of gravel pit ponds for floodplain wetland fish
Floodplain wetlands support high biodiversity, but they have been degraded and geographically fragmented due to human activities. Some types of human-created waterbodies have received growing attention as alternative habitats for conserving wetland biodiversity. Gravel pit ponds (GPPs) are human-created wetlands formed when a gravel pit is excavated at or below the water table and filled with groundwater. Differences in community structure among GPPs and floodplain wetlands with respect to habitat characteristics are scarcely known, resulting in insufficient evaluations of the ecological value of GPPs for floodplain wetland species. In this study, we evaluated the ecological value of GPPs for wetland fishes in floodplain landscapes. We surveyed fish abundance, community composition, and 10 environmental factors in GPPs and two types of floodplain ponds (remnant ponds and river backwaters) to clarify the biotic and abiotic differences among the pond types. Environmental factors were similar among the pond types, with only water temperature and the distance from the main channel to the pond significantly lower in river backwaters. The richness and abundance of native fish species did not differ among the pond types, but species composition did. Rhynchocypris percnura sachalinensis, Carassius sp., and Lethenteron sp. N (one of the two cryptic species of Lethenteron reissneri) were selected as indicator species in GPPs, remnant ponds, and river backwaters, respectively. These results indicate that GPPs provide valuable habitats for wetland fishes in floodplain landscapes and support regional gamma diversity. Since many species inhabited the GPPs in this study, including red list species, appropriate management of GPPs is important to conserve wetland fishes
Functional expression of choline transporter-like protein 1 (CTL1) in small cell lung carcinoma cells: A target molecule for lung cancer therapy
AbstractCholine is essential for the synthesis of the major membrane phospholipid phosphatidylcholine and the neurotransmitter acetylcholine (ACh). Elevated levels of choline and up-regulated choline kinase activity have been detected in cancer cells. Thus, the intracellular accumulation of choline through choline transporters is the rate-limiting step in phospholipid metabolism and a prerequisite for cancer cell proliferation. However, the uptake system for choline and the functional expression of choline transporters in lung cancer cells are poorly understood. We examined the molecular and functional characterization of choline uptake in the small cell lung carcinoma cell line NCI-H69. Choline uptake was saturable and mediated by a single transport system. Interestingly, removal of Na+ from the uptake buffer strongly enhanced choline uptake. This increase in choline uptake under the Na+-free conditions was inhibited by dimethylamiloride (DMA), a Na+/H+ exchanger (NHE) inhibitor. Various organic cations and the choline analog hemicholinium-3 (HC-3) inhibited the choline uptake and cell viability. A correlation analysis of the potencies of organic cations for the inhibition of choline uptake and cell viability showed a strong correlation (R=0.8077). RT-PCR revealed that choline transporter-like protein 1 (CTL1) mRNA and NHE1 are mainly expressed. HC-3 and CTL1 siRNA inhibited choline uptake and cell viability, and increased caspase-3/7 activity. The conversion of choline to ACh was confirmed, and this conversion was enhanced under Na+-free conditions, which in turn was sensitive to HC-3. These results indicate that choline uptake through CTL1 is used for ACh synthesis. Both an acetylcholinesterase inhibitor (eserine) and a butyrylcholinesterase inhibitor (ethopropazine) increased cell proliferation, and these effects were inhibited by 4-DAMP, a mAChR3 antagonist. We conclude that NCI-H69 cells express the choline transporter CTL1 which uses a directed H+ gradient as a driving force, and its transport functions in co-operation with NHE1. This system primarily supplies choline for the synthesis of ACh and secretes ACh to act as an autocrine/paracrine growth factor, and the functional inhibition of CTL1 could promote apoptotic cell death. Identification of this new CTL1-mediated choline transport system provides a potential new target for therapeutic intervention
Implementation of remote monitoring and diffraction evaluation systems at the Photon Factory macromolecular crystallography beamlines
At the Photon Factory macromolecular crystallography beamlines, two new functions, remote monitoring and diffraction image evaluation, have been developed and installed on the beamline controlling system STARS (simple transmission and retrieval system)
Radial Age and Metal Abundance Gradients in the Stellar Content of M32
We present long-slit spectroscopy of the elliptical galaxy M32, obtained with
the 8-m Subaru telescope at Mauna Kea, the 1.5-m Tillinghast telescope at the
F. L. Whipple Observatory, and the 4-m Mayall telescope at the Kitt Peak
National Observatory. The spectra cover the Lick index red spectral region as
well as higher order Balmer lines in the blue. Spectra have been taken with the
slit off-set from the nucleus to avoid scattered light contamination from the
bright nucleus of M32. An analysis of numerous absorption features,
particularly involving the H and H Balmer lines, reveals that
systematic radial trends are evident in the integrated spectrum of M32.
Population synthesis models indicate a radial change in both the age and
chemical composition of the light-weighted mean stellar population in M32, from
the nucleus out to 33", i.e., approximately 1.0 effective radius, R_e.
Specifically, the light-weighted mean stellar population at 1 R_e is older, by
\~3 Gyr, and more metal-poor, by ~-0.25 dex in [Fe/H], t han the central value
of ~4 Gyr and [Fe/H]~0.0. We show that this apparent population trend cannot be
attributed to a varying contribution from either hot stars or emission line
contamination. The increase in age and decrease in metal-abundance with radius
are sufficiently well-matched to explain the flat radial color profiles
previously observed in M32. In addition, the ratio of Mg to Fe abundance,
[Mg/Fe], increases from ~-0.25 in the nucleus to ~-0.08 at 1 R_e. Finally, we
find spuriously pronounced line strength gradients in the Mayall data that are
an artifact of scattered light from the bright nucleus. Scattered light issues
may explain the lack of consistency among previously published studies of
radial line strength gradients in M32.Comment: 25 pages, 14 figures, 3 tables, accepted for publication in the
Astronomical Journa
α-Naphthylisothiocyanate (ANIT) Induced Cholestasis in Rats
In order to distinguish the disorder of bile acid and cholesterol metabolism in α-naphthylisothiocyanate (ANIT)-induced cholestasis, we examined changes in bile acid levels and compositions in bile, serum, feces and urine, as well as cholesterol levels in bile, serum, liver and feces in Wistar male rats (10-13 weeks) after a single oral administration of 100 mg/kg of ANIT. The bile flow and the biliary secretions of cholesterol, phospholipids and bile acids markedly decreased on days 1 and 2 but increased over the normal values on day 4 and then returned to the normal ranges. The fecal excretion of bile acids decreased after the treatment and remained low by day 4 but markedly increased thereafter. The urinary excretion of bile acids changed almost in parallel with serum bile acid level, increasing to 37 mg/day on day 2, 28 mg/day on days 3-4 but to a trace on days 5-6. The urinary bile acids on day 2 mainly consisted of cholic acid while those on days 3-4 and biliary bile acids on day 4 were mostly β-muricholic acid. The serum cholesterol level markedly increased maximally on day 2 and decreased thereafter. The fecal excretion of sterols, cholesterol and coprostanol, decreased on days 1-2 but rather increased thereafter. These data suggest that the cholestasis induced by ANIT is very similar to that in bile duct ligated rats for a short period but not to those ligated for long periods. In addition, the present data suggest that the bile acid independent bile flow is impaired and the daily synthesis of bile acids, especially β-muricholic acid, is increased in the ANIT induced cholestasis
Clustering of red Galaxies near the Radio-loud Quasar 1335.8+2834 at z=1.1
We have obtained new deep optical and near-infrared images of the field of
the radio-loud quasar 1335.8+2834 at where an excess in the surface
number density of galaxies was reported by Hutchings et al. [AJ, 106, 1324]
from optical data. We found a significant clustering of objects with very red
optical-near infrared colors, and near the quasar. The colors and magnitudes of the reddest objects
are consistent with those of old (12 Gyr old at z=0) passively-evolving
elliptical galaxies seen at , clearly defining a `red envelope' like
that found in galaxy clusters at similar or lower redshifts. This evidence
strongly suggests that the quasar resides in a moderately-rich cluster of
galaxies (richness-class ). There is also a relatively large fraction
of objects with moderately red colors () which have a
distribution on the sky similar to that of the reddest objects. They may be
interpreted as cluster galaxies with some recent or on-going star formation.Comment: 14 pages text, 5 PostScript figures, 1 GIF figure, and 1 combined PS
file. Accepted for ApJ, Letter
Aerobic and Anaerobic Biotransformation of Bile Acids by Escherichia coli (III)
The oxidation/reduction reactions of bile acids by Escherichia coli (E. coli) K-12 were examined in both Davis and brain-heart infusion (BHI) media under aerobic and anaerobic conditions. The pH in the Davis medium changed by almost the same amount, around pH 6.5?7.0 in both aerobic and anaerobic cultures, but the pH in the BHI medium was different in both cultures, that is, about pH 9.0 in the aerobic culture but only about 6.5 in the anaerobic culture. The growth curve of E. coli in the Davis medium showed a similar pattern in both conditions. Cholic acid (CA) was oxidized to 3α12α-dihydroxy-7-oxo-5β-cholanoic acid (3α12α7=O) in both cultures, but the reaction in the anaerobic culture was somewhat slower than that in the aerobic culture. On the other hand, reduction of 3α12α7=O to CA did not occur in the aerobic culture, but about 10% reduction was observed in the anaerobic culture after 4 days. These data suggest that the oxidation/reduction reaction of E. coli was oxidative in aerobic culture but reductive in anaerobic culture and these characteristics were not due to the changes in the pH of the medium. The reactions of CA and glycocholic acid to crude 7α-HSDH prepared from E. coli were examined and it was found that both free and conjugated CA as a substrate for the 7α-HSDH showed similar Km values
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