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151.
DORIEN M. KOOL † HAEGEUN CHUNG KEVIN R. TATE‡ DES J. ROSS‡ PAUL C. D. NEWTON§ JOHAN SIX 《Global Change Biology》2007,13(6):1282-1293
Soil has been identified as a possible carbon (C) sink to mitigate increasing atmospheric CO2 concentration. However, several recent studies have suggested that the potential of soil to sequester C is limited and that soil may become saturated with C under increasing CO2 levels. To test this concept of soil C saturation, we studied a gley and organic soil at a grassland site near a natural CO2 spring. Total and aggregate‐associated soil organic C (SOC) concentration showed a significant increase with atmospheric CO2 concentration. An asymptotic function showed a better fit of SOC and aggregation with CO2 level than a linear model. There was a shift in allocation of total C from smaller size fractions to the largest aggregate fraction with increasing CO2 concentration. Litter inputs appeared to be positively related to CO2 concentration. Based on modeled function parameters and the observed shift in the allocation of the soil C from small to large aggregate‐size classes, we postulate that there is a hierarchy in C saturation across different SOC pools. We conclude that the asymptotic response of SOC concentration at higher CO2 levels indicates saturation of soil C pools, likely because of a limit to physical protection of SOC. 相似文献
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HEAVY meromyosin (HMM) fragments of myosin from striated muscle specifically bind with actin filaments to form complexes that are readily observed by electron microscopy1 in both negatively-stained preparations and sectioned material. The composite or “decorated filaments” appear like a line of arrowheads. The existence of such decorated filaments in cells or some cell fraction after treatment with HMM indicates that actin is present. Ishikawa et al.2 used this to demonstrate actin in a number of cultured cell types. More recently, other workers have similarly demonstrated actin filaments in slime mould3, amoebae4,5, blood platelets6, microvilli7, macrophages8 and, less convincingly, in sperm tails9 and the mitotic spindle10. We prove here that filaments from the cortical region of mouse neuroblastoma cells bind HMM and therefore contain actin. 相似文献
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PAUL R. FITZGERALD 《The Journal of eukaryotic microbiology》1974,21(2):336-338
Blood, withdrawn by heart puncture, from donor rabbits infected with Eimeria stiedai, was transfused by heart puncture, to uninfected recipient rabbits. Fifty-nine of 76 young coccidia-free recipients, given heparinized whole blood, erythrocytes or leucocytes from donors orally inoculated up to 27 days earlier, developed E. stiedai infections. 相似文献
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SYNOPSIS. Notification is given of the deposit of paratype material of 36 species of Myxosporida. described by Prof. R. R. Kudo, with the U. S. National Museum. 相似文献
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Metal-replete cuticle was characterised by back-scattered electron imaging, secondary ion mass spectrometry, proton induced X-ray emission and SEM-X-ray microanalysis. Each technique was found to have singular advantages and limitations for localising and quantifying metal content. Manganese and zinc were found coincident at the mandibular cutting edge of the leaf-cutting ant Atta sexdens; these two metals were found in different zones within jaws of the ragworm, Nereis virens; while only manganese was found in the jaws of the termite C. cumulans. 相似文献