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61.
The datasets of net ecosystem CO2 exchange (NEE) were acquired from 21 forests, 3 grasslands, and 3 croplands in the eastern part of Asia based on the eddy covariance measurements of the international joint program, CarboEastAsia. The program was conducted by three networks in Asia, ChinaFLUX, JapanFlux, and KoFlux, to quantify, synthesize, and understand the carbon budget of the eastern part of Asia. An intercomparison was conducted for NEE estimated by three gap-filling procedures adopted by ChinaFLUX, JapanFlux, and KoFlux to test the range of uncertainty in the estimation of NEE. The overall comparison indicated good agreement among the procedures in the seasonal patterns of NEE, although a bias was observed in dormant seasons depending on the different criteria of data screening. Based on the gap-filled datasets, the magnitude and seasonality of the carbon budget were compared among various biome types, phenology, and stress conditions throughout Asia. The annual values of gross primary production and ecosystem respiration were almost proportional to the annual air temperature. Forest management, including clear-cutting, plantation, and artificial drainage, was significant and obviously affected the annual carbon uptake within the forests. Agricultural management resulted in notable seasonal patterns in the crop sites. The dataset obtained from a variety of biome types would be an essential source of knowledge for ecosystem science as well as a valuable validation dataset for modeling and remote sensing to upscale the carbon budget estimations in Asia.  相似文献   
62.
The wave attenuation function of a Japanese black pine forest was evaluated based on its growth at different initial planting densities (P ini) using the spatially explicit, individual-based, dynamic global vegetation model. The forest dynamics were simulated for 150 years utilizing datasets for tree density and stem diameter at different stand ages obtained in the field. To elucidate the ability of the forest to reduce the wave height $ \eta_{t} $ (m), a long linear wave that propagates on dry ground was assumed. The attenuation of $ \eta_{t} $ (m) was expressed as follows: $ \eta_{t} = \eta_{t0} \exp ( - k_{\text{i}} x) $ , where $ \eta_{t0} $ , x, and k i are the initial wave height (m), the distance (m), and the wave attenuation coefficient (m?1), respectively. The tree destruction caused by the waves was considered in order to estimate k i. The model suggested that there was a peak age that maximized k i and was dependent on $ \eta_{t} $ , and that the maximum k i attained decreased with increasing $ \eta_{t} $ . When P ini was varied widely from 0.5 to 4 m?2, the maximum k i for a relatively low wave height (≤3 m) changed dramatically. For example, when $ \eta_{t} = 2{\text{ m}},$ the maximum k i ranged from 0.008 to 0.031 m?1, depending on P ini. Thus, utilizing a relatively low P ini would be an efficient way of quickly creating a forest capable of sufficient wave attenuation in areas where a relatively high wave height (≥4 m) is expected. It was concluded that regular harvesting and planting would be required to realize the full potential of the coastal forests to attenuate waves, and that tailoring P ini is one of the management options that could be used to establish a wave prevention forest.  相似文献   
63.
The effects of NaCl stress on plant growth, gas-exchange, activity of superoxide dismutase (SOD), rate of lipid peroxidation, and accumulation of Na+ ion and sugar were investigated in leaves and fruits of pepper plants (Capsicum annuum L.). Especially, the gene expression of l-galactono-1,4-lactone dehydrogenase (GalLDH), which is the last enzyme of ascorbic acid (AsA) biosynthesis, and the relationships between AsA level and Na+ concentration in plant tissue were investigated with increasing salinity. Plants were treated with three treatments: the control (0 mM NaCl) and two salinity levels (50 and 100 mM NaCl) for 21 days under greenhouse conditions. Plant growth was markedly restricted due to the reduction of photosynthetic rate and the increase of Na+ accumulation in leaves with the increasing intensity of NaCl stress. Salinity had more effect on fruit growth comparing to leaf growth, suggesting that fruits could be more sensitive to salinity than leaves. In comparison with the control, salt stress significantly increased lipid peroxidation (as measured as malondialdehyde content) but decreased SOD activity in both fruits and leaves although the effect was larger in fruits; and the rate of the decrease in SOD activity was greater than that of the increase in lipid peroxidation. The AsA concentration transiently increased first 7 days but it slightly decreased from the initial level in the end of treatment day 21. The change in GalLDH gene expression was similar to AsA concentration. The accumulation of Na+, the reduction of AsA level at severe salinity stress were greater in fruits than in leaves; and AsA level had a negative relationship with Na+ concentration in both leaves and fruits. These results suggest that the difference in salt sensitivity between fruits and leaves in pepper plants can be related to the difference in inhibition of AsA synthesis, which in turn is probably due to the toxicity of extreme accumulation of Na+.  相似文献   
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Successful regeneration and remodeling of neuromuscular junctions are critical for restoring functional capacities and properties of skeletal muscle after damage, and axon‐guidance molecules may be involved in the signaling that regulates such restoration. Recently, we found that early‐differentiated satellite cells up‐regulate a secreted neural chemorepellent Sema3A upon in vivo muscle‐crush injury. The study also revealed that Sema3A expression is up‐regulated in primary satellite‐cell cultures in response to hepatocyte growth factor (HGF) and basic fibroblast growth factor (FGF2) and is prevented by transforming growth factor (TGF)‐β2, 3. In order to verify the physiological significance of this regulation in vitro, the present study was designed to estimate the time‐course of extracellular HGF, FGF2 and TGF‐β3 concentrations after crush‐injury of Gastrocnemius muscle in the rat lower hind‐limb, using a combination of a non‐homogenization/non‐spin extraction of extracellular wound fluids and enhanced chemiluminescence–Western blotting analyses. Results clearly demonstrated that active HGF and FGF2 are prevalent in 2–8 days post‐crush, whereas active TGF‐β3 increases after 12 days, providing a better understanding of the time‐coordinated levels of HGF, FGF2 and TGF‐β3 that drive regulation of Sema3A expression during regenerative intramuscular moto‐neuritogenesis.  相似文献   
67.
The kinetics of the antigen production of Chlamydia psittaci strains Izawa-1 and Pigeon-1041 (P-1041) was examined every 6 hr after infection up to 48 hr, by the indirect immunofluorescent antibody technique using monoclonal antibodies (MAbs). All three genus-specific antigenic determinants on lipopolysaccharide (LPS) appeared during the whole growth cycle. Antigenic determinants on proteins were, on the other hand, detected at various time periods from the early to the late stages of infection. However, a cross-reactive antigenic determinant on protein recognized by a MAb 3E9 was also detected during the whole growth cycle, similar to that on LPS. The time of appearance of common antigenic determinants on proteins of Izawa-1 and P-1041 was examined using cross-reactive MAbs, and it varied depending on heterologous and homologous MAbs. From the relationship between the detection of antigenic determinants and the morphological changes of chlamydial particles revealed by electron microscopy during the growth cycle, the antigenic determinants on proteins of Chlamydia psittaci were divided into two groups; one was specific to the elementary body and the other was coexisting in both the elementary body and the reticulate body.  相似文献   
68.
Pathology of experimental chlamydiosis in chicks   总被引:1,自引:0,他引:1  
Twelve one-day-old chicks were experimentally inoculated with Chlamydia psittaci derived from turkeys. Acute chlamydial septicemic lesions were induced by the inoculation into the air sac and trachea. No lesions were produced by the esophageal injection. Clinically, the affected chicks showed emaciation and mouth breathing, and were inactive while some birds died. Grossly, they had hepatomegaly, splenomegaly and airsacculitis. Histopathologically, fibrinopurulent airsacculitis, pneumonia and bronchitis, multiple fibrinous serositis in the hepatic and splenic capsules, peri- and epicardium, and mesenterium, focal endoarteritis in the aortae, activation of reticuloendothelial cells in the spleen, and hepatic necrosis were noted. Immunohistochemically, chlamydial antigen granules were present in the cytoplasm of epithelial cells of the respiratory system, hepatocytes, macrophages in the air sac, lung, serous membrane, liver, spleen, aortae, reticuloendothelial cells in the spleen, and mesothelial cells in various organs or tissues. Chlamydial multiplication in the cells of the organs or tissues involved was preceded to form the lesions.  相似文献   
69.
To develop an easy method of typing of mitochondrial DNA (mtDNA) in Hokkaido brown bears (Ursus arctos yesoensis), the PCR-RFLP technique was improved using four restriction enzymes: Mbo 1, Cfr 13 I, TspE 1, and Fok 1. This approach identified seven groups of mtDNA haplotypes, HB1/2/5-7, HB 3, HB4, HB8/9, HB10/11, HB12 and HB13 from 102 brown bears of northern, central and eastern Hokkaido.  相似文献   
70.
It has previously been shown that mechanical stretch induces activation of cultured quiescent satellite cells by rapid release of hepatocyte growth factor (HGF) from its extracellular association with satellite cells and its subsequent presentation to the c‐met receptor. The present study provides evidence that the stretch activation activity varies according to the origin of satellite cells from back and leg skeletal muscles in vitro. Satellite cells were isolated from three muscle groups, back (BK), upper hind limb (UL) and lower hind limb (LL) muscles, of adult male rats and stretch activation activities were compared. In response to stretch, lower hind limb satellite cells showed significantly greater response than upper hind limb and back muscles (LL > UL > BK). Immunoblots of stretched culture media revealed a higher HGF‐releasing capacity of lower hind limb satellite cells than back muscle satellite cells. In addition, lower hind limb satellite cells exhibited a greater activation activity in response to exogenous HGF added to culture media than compared to satellite cells from back and upper hind limb (LL > UL > BK). The increased ability to release HGF and the increased cellular responsiveness might account for higher stretch activation activities of lower hind limb satellite cells. Electrophoretic analysis of myosin heavy chain isoforms verified a higher content of slow muscle fibers in lower limb muscles (LL > UL > BK), suggesting a difference in stretch‐induced activation activity between satellite cells associated with fast and slow muscle fibers.  相似文献   
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