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31.
Comparison of telomere length among different life cycle stages of the jellyfish Cassiopea
andromeda
The polyp (scyphistoma) of the jellyfish Cassiopea andromeda reproduces asexually repeatedly, while the medusa, the sexually reproducing stage, exhibits a relatively shorter life span.
As a first step to understand the mechanism behind the differences in the life spans of the polyp and medusa stages of the
jellyfish, we compared the lengths of the telomere region of one targeted chromosome between the polyp and medusa stages using
a modified single telomere length assay (STELA). The double-stranded regions of the telomeres were amplified by PCR, and the
average length of the PCR products was estimated by densitometry analysis of the gel smear. Chromosomes within cells of the
bell region of the medusa were characterized by longer telomeres than those of polyps, asexual propagules, or other regions
of the medusa. This is the first study to estimate the telomere lengths of targeted chromosomes in a cnidarian and opens a
way to understand the mechanism underlying different life spans of the polyp and medusa stages. 相似文献
32.
When wind-induced water waves appear over the free-surface flows such as natural rivers and artificial channels, large amounts
of oxygen gas and heat are transported toward the river bed through the interface between water and wind layers. In contrast,
a bed region is a kind of turbulent boundary layer, in which turbulence generation and its transport is promoted by the production
of bed shear stress. In particular, coherent hairpin vortices, together with strong ejection events toward the outer part
of the layer, promote mass and momentum exchanges between the inner and outer layers. It is inferred that such a near-bed
turbulence may be influenced significantly by these air–water interfacial fluctuations accompanied with free-surface velocity
shear and wind-induced water waves. However, these wind effects on the wall-turbulence structure are less understood. To address
these exciting and challenging topics, we conducted particle imagery velocimetry (PIV) measurements in open-channel flows
combined with air flows, and furthermore the present measured data allows us to investigate the effects of air–water interactions
on turbulence structure through the whole depth region. 相似文献
33.
Watanabe M Adams RM Wu J Bolte JP Cox MM Johnson SL Liss WJ Boggess WG Ebersole JL 《Journal of environmental management》2005,75(2):93-104
This paper integrates economic, biological, and physical models to explore the efficient combination and spatial allocation of conservation efforts to protect water quality and increase salmonid populations in the Grande Ronde basin, Oregon. We focus on the effects of shade on water temperatures and the subsequent impacts on endangered juvenile salmonid populations. The integrated modeling system consists of a physical model that links riparian conditions and hydrological characteristics to water temperature; a biological model that links water temperature and riparian conditions to salmonid abundance, and an economic model that incorporates both physical and biological models to estimate minimum cost allocations of conservation efforts. Our findings indicate that conservation alternatives such as passive and active riparian restoration, the width of riparian restoration zones, and the types of vegetation used in restoration activities should be selected based on the spatial distribution of riparian characteristics in the basin. The relative effectiveness of passive and active restoration plays an important role in determining the efficient allocations of conservation efforts. The time frame considered in the restoration efforts and the magnitude of desired temperature reductions also affect the efficient combinations of restoration activities. If the objective of conservation efforts is to maximize fish populations, then fishery benefits should be directly targeted. Targeting other criterion such as water temperatures would result in different allocations of conservation efforts, and therefore are not generally efficient. 相似文献
34.
The atmospheric deposition of reactive nitrogen on turf grassland in Tsukuba, central Japan, was investigated from July 2003
to December 2004. The target components were ammonium, nitrate, and nitrite ions for wet deposition and gaseous ammonia, nitric
and nitrous acids, and particulate ammonium, nitrate, and nitrite for dry deposition. Organic nitrogen was also evaluated
by subtracting the amount of inorganic nitrogen from total nitrogen. A wet-only sampler and filter holders were used to collect
precipitation and the atmospheric components, respectively. An inferential method was applied to calculate the dry deposition
velocity of gases and particles, which involved the effects of surface wetness and ammonia volatilization through stomata
on the dry deposition velocity. The mean fraction of the monthly wet to total deposition was different among chemical species;
37, 77, and 1% for ammoniacal, nitrate-, and nitrite-nitrogen, respectively. The annual deposition of inorganic nitrogen in
2004 was 47 and 48 mmol m−2 yr−1 for wet and dry deposition, respectively; 51% of atmospheric deposition was contributed by dry deposition. The annual wet
deposition in 2004 was 20, 27, and 0.07 mmol m−2 yr−1, and the annual dry deposition in 2004 was 35, 7.4, and 5.4 mmol m−2 yr−1 for ammoniacal, nitrate-, and nitrite-nitrogen, respectively. Ammoniacal nitrogen was the most important reactive nitrogen
because of its remarkable contribution to both wet and dry deposition. The median ratio of the organic nitrogen concentration
to total nitrogen was 9.8, 17, and 15% for precipitation, gases, and particles, respectively. 相似文献
35.
Akira Hoshino Maso Tsuji Masanori Momochi Akiko Mizutani Hideo Sawada Setsuo Kohnami Hiroki Nakagomi Michio Ito Hisato Saida Munehiro Ohnishi Michimasa Hirata Masao Kunioka Masahiro Funabash Shogo Uematsu 《Journal of Polymers and the Environment》2007,15(4):275-280
Several ISO standards for determining the ultimate aerobic/anaerobic biodegradability of plastic materials have been published.
In particular, ISO 14855-1 is a common test method that measures evolved carbon dioxide using such methods as continuous infrared
analysis, gas chromatography or titration and others (ISO 14855-1(2005.9)). This method is a small-scale test for determining
the ultimate aerobic biodegradability of plastic materials, where the amounts of compost inoculum and test sample in one tenth
comparing with that of ISO 14855-1. This method is well versed in ISO/DIS 14855-2 which the carbon dioxide evolved from test
vessel is determined by gravimetric analysis of carbon dioxide absorbent. The focus of this study is to elucidate statistically
the results of round robin test by seven countries used MODA, which were various deviations among the experiments. 相似文献
36.
We have found that giant hornets (Vespa mandarinia japonica) are killed in less than 10 min when they are trapped in a bee ball created by the Japanese honeybees Apis cerana japonica, but their death cannot be solely accounted for by the elevated temperature in the bee ball. In controlled experiments, hornets
can survive for 10 min at the temperature up to 47°C, whereas the temperature inside the bee balls does not rise higher than
45.9°C. We have found here that the CO2 concentration inside the bee ball also reaches a maximum (3.6 ± 0.2%) in the initial 0–5 min phase after bee ball formation.
The lethal temperature of the hornet (45–46°C) under conditions of CO2 concentration (3.7 ± 0.44%) produced using human expiratory air is almost the same as that in the bee ball. The lethal temperature
of the honeybee is 50–51°C under the same air conditions. We concluded that CO2 produced inside the bee ball by honeybees is a major factor together with the temperature involved in defense against giant
hornets. 相似文献
37.
Effect of the carbon coating in Fe-C-TiO(2) photocatalyst on phenol decomposition under UV irradiation via photo-Fenton process 总被引:1,自引:0,他引:1
Fe-C-TiO(2) photocatalysts which contained the residue carbon (0.2-3.3 mass%) were prepared from a mixture of TiO(2) and FeC(2)O(4) through the heating at 673-1173 K in Ar. These photocatalysts did not show a high adsorption of phenol, but they were active in photo-Fenton reactions during decomposition of phenol under UV irradiation with addition of H(2)O(2). It was proved that Fe(2+) governed the photoactivity of Fe-C-TiO(2) photocatalysts, it decreased with heat-treatment temperature above 773 K. For comparison, Fe-TiO(2) photocatalyst was prepared by heating TiO(2) and FeC(2)O(4) at 823 K in air for 3h. Phenol decomposition was going much slower on Fe-TiO(2) photocatalyst in comparison with Fe-C-TiO(2), of which mechanism was different, on the former phenol was decomposed by the radical reaction, on the latter through a complex reaction with iron and intermediates of phenol decomposition. Therefore carbon-coating TiO(2) was found to be advantageous for mounting iron and its application for the phenol decomposition via photo-Fenton process. 相似文献
38.
Ubiquity of parasporin-1 producers in <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> natural populations of Japan 总被引:1,自引:0,他引:1
Uemori A Maeda M Yasutake K Ohgushi A Kagoshima K Mizuki E Ohba M 《Die Naturwissenschaften》2007,94(1):34-38
Parasporin, a Bacillus thuringiensis parasporal protein, is unique in having a strong cytocidal activity preferential for human cancer cells. In this study, we
characterized parasporin activities associated with three novel geographical isolates of B.
thuringiensis. Parasporal inclusion proteins of the three isolates were highly toxic to human uterus cervix cancer cells (HeLa), but not
to non-cancer uterine smooth muscle cells (UtSMC). Inclusions of the isolates lacked insect toxicity and hemolytic activity
against sheep erythrocytes. Ouchterlony immunodiffusion tests revealed that the proteins of the three isolates are immunologically
closely related to parasporin-1 (Cry31A), but dissimilar to the three other existing parasporin groups. Our results provide
evidence that the parasporin-1-producing organism is a common member in B. thuringiensis populations occurring in natural environments of Japan. 相似文献
39.
Chlordane compounds (CHLs) were quantitated in krill (Euphausia superba), benthic fish (Trematomus bernacchii) and Weddell seal (Leptonychotes weddelli) collected around the Japanese Antarctic Research Station (Syowa Station: 69°00'S, 39°35'E). The concentrations of ZCHL (cis‐, trans‐chlordane+ cis‐, fraws‐nonachlor + oxych‐lordane) in krill was much lower than that of benthic fish. The ratio of SCHL to sum of SCHL, SDDT and PCBs decreased with the trophic levels. These results indicate that CHLs appear to be easily degraded in higher organisms. 相似文献
40.
The criteria of ovarian maturity during the spawning season and maturity rates according to age are described for the female
red sea bream Pagrus major collected from the Chikuzenkai between April and June, 1984. The degree of maturity of the ovary is categorized into four
stages based on the maturation stage of the most advanced oocytes in the ovary, rate of atresia and occurrence of post-ovulatory
follicles. The ovarian maturity rates in fish aged 2, 3, 4 and 5 years were shown to be 5.8, 46.2, 75.0 and 97.3%, respectively,
assuming that yolked ovaries with low levels of atresia (<50% yolked oocytes affected) attain maturity. The fork length at
which 50% of the fish attained maturity ranged from 280 to 300 mm. 相似文献