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The stable isotope ratios of nitrogen were measured in the mysid,Neomysis intermedia, together with various biogenic materials in a eutrophic lake, Lake Kasumigaura, in Japan throughout a year of 1984/85. The mysid, particulate organic matter (POM, mostly phytoplankton), and zooplankton showed a clear seasonal change in 15N with high values in spring and fall, but the surface bottom mud did not. A year to year variation as well as seasonal change in 15N was found in the mysid. The annual averages of 15N of each material collected in 1984/85 are as follows: surface bottom mud, 6.3 (range: 5.7–6.9); POM, 7.9 (5.8–11.8); large sized mysid, 11.6 (7.7–14.3); zooplankton, 12.5 (10.0–16.4); prawn, 13.2 (9.9–15.4); goby, 15.1 (13.8–16.7). The degree of15N enrichment by the mysid was determined as 3.2 by the laboratory rearing experiments. The apparent parallel relationship between the POM and the mysid in the temporal patterns of 15N with about 3 difference suggests the POM (mostly phytoplankton) as a possible food source ofN. intermedia in this lake through the year. 相似文献
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Alterations to river flow conditions have wide impacts on riparian organisms in terms of behavior and biomass. However, little
is known about natural flood impacts on prey use and individual growth of riparian predators. Using stable carbon isotope
analysis, we investigated flood impacts on aquatic-prey use and the size structure of an orb-web spider, Nephila clavata, during 3 years under different flood conditions in a black locust forest in the middle reaches of the Chikuma River. Large
floods depressed aquatic-prey abundance, but did not affect terrestrial-prey abundance in the riparian forest. Consequently,
spider growth was stunted after large floods. Spider body size was positively correlated with the body sizes of both aquatic
and terrestrial insects in spider webs, where terrestrial insects were significantly larger than aquatic insects. The δ13C of aquatic insects was about 8‰ higher than that of terrestrial insects, and the δ13C of both insect groups did not vary significantly between months or among years. A negative relationship was found between
body size and δ13C in spiders under different subsidies levels. Our results showed that flow regime altered spider growth through changes in
aquatic subsidies level, but not aquatic-prey use by the spiders due to relative body sizes of predators and prey. Changes
in relative body sizes of predator and prey may be an important factor in understanding nutrients, materials, and energy flows
in aquatic and terrestrial linkages in the context of flow regime. 相似文献
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Fumikazu Akamatsu Koichi Ide Koji Shimano Hideshige Toda 《Landscape and Ecological Engineering》2011,7(1):109-115
Fixation of river flow passages and riverbed degradation may facilitate the development of higher floodplains with the establishment
of exotic species such as black locust (Robinia pseudoacacia L.). We quantitatively evaluated the relationship between nitrogen (N) levels in black locust trees and in sediments under
different flood disturbance regimes in a riparian area of the Chikuma River. In this study, allometric equations were developed
for relating leaf N content to diameter at breast height of black locust. The amount of leaf N in black locust increased with
distance from the river, reaching 159 kg N ha−1 at 180 m from the river. There was a small difference in N content between green and fallen leaves (0.2%), and so the leaf
N was almost equivalent to N input to riparian sediments. Fine sediments accumulated on the riparian area, where the amount
of sediments N increased with distance from the river, ranging from 1091 ± 767 to 4953 ± 2953 kg N ha−1. The N accumulation rates also increased with distance from the river, corresponding with the amount of leaf N in black locust
per unit area, but the former exceeded the latter. The sediment N accumulation might be accelerated by sediment trapping effect
due to riparian vegetation itself. A large input of N provided by invaded black locust might alter nutrient dynamics and native
plant community structure in the riparian area. 相似文献
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Emma L. Teuten Jovita M. Saquing Detlef R. U. Knappe Morton A. Barlaz Susanne Jonsson Annika Bj?rn Steven J. Rowland Richard C. Thompson Tamara S. Galloway Rei Yamashita Daisuke Ochi Yutaka Watanuki Charles Moore Pham Hung Viet Touch Seang Tana Maricar Prudente Ruchaya Boonyatumanond Mohamad P. Zakaria Kongsap Akkhavong Yuko Ogata Hisashi Hirai Satoru Iwasa Kaoruko Mizukawa Yuki Hagino Ayako Imamura Mahua Saha Hideshige Takada 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2009,364(1526):2027-2045
Plastics debris in the marine environment, including resin pellets, fragments and microscopic plastic fragments, contain organic contaminants, including polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons, petroleum hydrocarbons, organochlorine pesticides (2,2′-bis(p-chlorophenyl)-1,1,1-trichloroethane, hexachlorinated hexanes), polybrominated diphenylethers, alkylphenols and bisphenol A, at concentrations from sub ng g–1 to µg g–1. Some of these compounds are added during plastics manufacture, while others adsorb from the surrounding seawater. Concentrations of hydrophobic contaminants adsorbed on plastics showed distinct spatial variations reflecting global pollution patterns. Model calculations and experimental observations consistently show that polyethylene accumulates more organic contaminants than other plastics such as polypropylene and polyvinyl chloride. Both a mathematical model using equilibrium partitioning and experimental data have demonstrated the transfer of contaminants from plastic to organisms. A feeding experiment indicated that PCBs could transfer from contaminated plastics to streaked shearwater chicks. Plasticizers, other plastics additives and constitutional monomers also present potential threats in terrestrial environments because they can leach from waste disposal sites into groundwater and/or surface waters. Leaching and degradation of plasticizers and polymers are complex phenomena dependent on environmental conditions in the landfill and the chemical properties of each additive. Bisphenol A concentrations in leachates from municipal waste disposal sites in tropical Asia ranged from sub µg l–1 to mg l–1 and were correlated with the level of economic development. 相似文献
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Establishment and characterization of tartrate-resistant acid phosphatase and alkaline phosphatase double positive cell lines 总被引:3,自引:0,他引:3
Riako Masuda Hisako Sakiyama Takashi Nonaka Alvin Kwan Koichi Nakagawa Hideshige Moriya Shinobu Imajoh-Ohmi Midori Honjo Kazuko Yoshida 《Cell and tissue research》2001,304(3):351-359
Morphologically macrophage-like cells were cloned from hamster bone marrow cells by coculturing bone marrow cells with hamster chondrocytes. One of the clones (CCP-2) was characterized in the present study. CCP-2 cells were positive in an osteoclast marker enzyme, tartrate-resistant acid phosphatase (TRAP), alkaline phosphatase (ALP) and non-specific esterase (NSE). We showed CCP-2 cells degraded cartilage matrix and hydroxyapatite coated on Osteologic disks. A gelatinase secreted from CCP-2 cells was observed and purified from serum-free conditioned medium of the cells. N-terminal amino acid sequencing of the purified enzyme revealed it was matrix metalloproteinase-9. However, CCP-2 cells failed to express calcitonin receptors, a mature osteoclast marker, even after coculture with osteoblast ST2 cells in the presence of 1alpha, 25-dihydroxyvitamin D3 [1alpha, 25-(OH)2D3]. The cells showed high affinity to types X and I but not to type II collagen. In addition, histochemical studies have shown the presence of tartrate-resistant acid phosphatase and alkaline phosphatase double positive cells at the secondary ossification site of the hamster humerus. From these observations, we concluded that CCP-2 cells are similar to osteoclast but not the same. CCP-2 cells are therefore important tools for investigating chondroclastogenesis/osteoclastogenesis and endochondral ossification. 相似文献
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Kazuhide Hayakawa Ryouji Okumura Hiroki Yamamoto Manabu Fujiwara Nobuhisa Yamaji Hideshige Takada Masakazu Kanematsu Yoshihisa Shimizu 《Limnology》2007,8(3):251-259
Distributions of fluorescent whitening agents (FWAs) in the waters of a small river system in Japan were surveyed in summer
when the water volume rose following high precipitation and in winter when it subsided as precipitation declined. The main
source of FWAs in the river system was domestic wastewater, and fluxes in the tributaries depended on the size of the residential
population and the elimination rates of sewage treatment systems in their catchments, although FWA concentrations in the river
itself fluctuated, largely as a consequence of dilution by heavy precipitation and unstable water flows in the small-sized
river system. The FWA concentrations in the river waterduring summer decreased not only by the dilution of river water but
also by photodegradation because of more prolonged exposure to sunlight. 相似文献