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421.
Elizabete Marchante Annelise Kjøller Sten Struwe Helena Freitas 《Biological invasions》2009,11(4):813-823
Invasion by Acacia longifolia alters soil characteristics and processes. The present study was conducted to determine if the changes in soil C and N pools and processes induced by A. longifolia persist after its removal, at the São Jacinto Dunes Nature Reserve (Portugal). Some areas had been invaded for a long time (>20 years) and others more recently (<10 years). For each type of invasion, (i.e., long-invaded and recently invaded), three treatments were used: (1) A. longifolia left intact; (2) A. longifolia was removed; and (3) both A. longifolia and litter layer were removed. Soil samples were collected once a year for four and half years and analysed for chemical and microbial properties. In general, microbial parameters responded faster than C and N pools. In long-invaded areas, two and half years after removal of plants and litter, basal respiration and microbial biomass had already decreased >30%, β-glucosaminidase activity (N mineralization index) >60% and potential nitrification >95%. Removal of plants and litter resulted in a >35% decrease in C and N content after four and half years. In recently invaded areas, β-glucosaminidase activity and potential nitrification showed a marked decrease (>54% and >95%, respectively) after removal of both A. longifolia and litter. Our results suggest that after removal of an N2-fixing invasive tree that changes ecosystem-level processes, it takes several years before soil nutrients and processes return to pre-invasion levels, but this legacy slowly diminish, suggesting that the susceptibility of native areas to (re)invasion is a function of the time elapsed since removal. Removal of the N-rich litter layer facilitates ecosystem recovery. 相似文献
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Boris Zhivotovsky David H. Burgess Jrg Schlegel M. Isabella Prn Daina Vanags Sten Orrenius 《Journal of cellular biochemistry》1997,64(1):43-49
Involvement of a unique family of cysteine proteases in the multistep apoptotic process has been documented. Cloning of several mammalian genes identifies some components of this cellular response. However, it is currently unclear which protease plays a role as a signal and/or effector of apoptosis. We summarize contributions to the data concerning proteases in Fas-mediated apoptosis. J. Cell. Biochem. 64:43–49. © 1997 Wiley-Liss, Inc. 相似文献
424.
Mancini MC Costa AP de Melo ME Cercato C Giannella-Neto D Garrido AB Rosberg S Albertsson-Wikland K Villares SM Halpern A 《Obesity (Silver Spring, Md.)》2006,14(3):383-387
Objective : The purpose of this study was to analyze growth hormone (GH) concentrations in obese women before and after Roux‐en‐Y gastric bypass (RYGBP) and how resulting changes in weight, fat mass, ghrelin levels, and insulin sensitivity affect GH secretion. Research Methods and Procedures : Blood was sampled at 20‐minute intervals for 24 hours in 10 non‐diabetic premenopausal severely obese women before and 6 months after RYGBP. GH concentrations were measured in all samples, and serum ghrelin was collected at five time‐points. Results : After a 27% BMI drop (55.9 ± 6.2 to 40.7 ± 5.8 kg/m2), blunted GH profiles underwent partial recovery. Basal, postprandial, and mean ghrelin concentrations were not changed. A negative correlation was found between mean GH levels and insulin and homeostasis model assessment (p < 0.01). BMI accounted for 54% of GH variation. Discussion : Partial recovery of GH secretion after RYGBP‐induced weight loss suggests that a blunted secretion is not a causal factor of obesity but a consequence of the obese state and does not seem to be ghrelin‐level dependent. 相似文献
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Hypoxia Due to Cardiac Arrest Induces a Time-Dependent Increase in Serum Amyloid �� Levels in Humans
Henrik Zetterberg Erik M?rtberg Linan Song Lei Chang Gail K. Provuncher Purvish P. Patel Evan Ferrell David R. Fournier Cheuk W. Kan Todd G. Campbell Ray Meyer Andrew J. Rivnak Brian A. Pink Kaitlin A. Minnehan Tomasz Piech David M. Rissin David C. Duffy Sten Rubertsson David H. Wilson Kaj Blennow 《PloS one》2011,6(12)
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Microbial changes during oil decomposition in soil 总被引:2,自引:0,他引:2
An examination has been made of the changes in bacterial and fungal populations during the decomposition of oil in contaminated soil. The number of aerobic and anaerobic bacteria and the length of mycelium increased in the oily soil whereas the number of CFU (= colony forming units) of fungi was highest in a control soil. The percentage of oil-utilizing fungi increased from 60% to 82%, while the bacterial utilization figure increased from 3% to 50%. The important oil-utilizing fungus Scolecobasidium appeared only in the oily soil, but otherwise the composition of the fungal flora changed only little after addition of oil. In laboratory experiments the chemical Pajab FI was shown to increase microbial activity. 相似文献
429.
Grillner S 《Current biology : CB》2011,21(20):R835-R836
430.
Burgdorf KS Grarup N Justesen JM Harder MN Witte DR Jørgensen T Sandbæk A Lauritzen T Madsbad S Hansen T;DIAGRAM Consortium Pedersen O 《PloS one》2011,6(1):e15813