Plant-derived CO2 flux from cultivated peat soils     

Örjan Berglund  Kerstin Berglund  Leif Klemedtsson 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(6):508-513

Abstract

Methods used to estimate the CO₂ emission from soil commonly measure the total CO₂ flux. To be able to quantify the net CO₂ emission from cultivated peat soils there is a need to distinguish between soil organic matter-derived CO₂ respiration and plant-derived respiration. In this investigation we used the root exclusion method to separate the plant-derived respiration from total CO₂ emission. The plant-derived contribution was estimated to be between 27 and 63% of total CO₂ emission depending on soil type and season. We also found a relationship between soil temperature, biomass growth and CO₂ efflux, which can be used to estimate plant-derived respiration. Due to the priming effect the root exclusion method is less reliable late in the season.  相似文献   

Effects of Family Housing on Behaviour,Plasma Cortisol and Performance in Adult Female Mink (Mustela vison)     

Vivi Pedersen  Leif Lau Jeppesen 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(1):77-88

Various behavioural, physiological and production-related parameters were examined in 200 adult female pastel and pearl mink either family housed in three-room cages with no weaning or housed singly in one-room cages after normal weaning procedures. Scanning observations of behaviour and use of the cages were performed in the nursing period and several parameters related to reproduction were registered. The adult female mink were weighed when kits were 16 weeks old (September) and again at pelting time (November). Blood samples were collected from all adult female mink in September at which time the teat condition and fur damage were evaluated. After pelting, bite marks on the leather side of the skin were counted, fur damage was graded after severity and the fur size was measured. Some positive consequences of being family housed were revealed. The familyhoused adult female mink showed a lower level of stereotypes and a higher level of defensiveness and curiosity than the adult female mink in one-room cages during the nursing period. In September and November, family-housed adult females were heavier than singly housed adult females. However, most of the physiological or production-related parameters pointed in a negative direction for familyhoused adult female mink. Reproductive success was somewhat reduced, although not significantly. Plasma cortisol levels were elevated in September, indicating higher levels of stress in these females. They showed a generally poor teat condition in September, with a high proportion of swollen or bitten teats. A high proportion of these adult females showed fur damage in both September and November, and a high number of bite marks was found on the leather side of the skins of these females, indicating that family housing had a high cost for the adult female mink. In conclusion, there seem to be some benefits, at least on the behavioural level, in keeping adult female mink in three-room cages during the nursing period, but both physiological and production-related parameters indicated that the welfare of the adult female mink was threatened if she was continuously cohoused with her litter past the normal age of weaning.  相似文献   

c-Jun N-Terminal Kinase Phosphorylation Is a Biomarker of Plitidepsin Activity     

María J. Mu?oz-Alonso  Enrique álvarez  María José Guillén-Navarro  Marina Pollán  Pablo Avilés  Carlos M. Galmarini  Alberto Mu?oz 《Marine drugs》2013,11(5):1677-1692

Plitidepsin is an antitumor drug of marine origin currently in Phase III clinical trials in multiple myeloma. In cultured cells, plitidepsin induces cell cycle arrest or an acute apoptotic process in which sustained activation of c-Jun N-terminal kinase (JNK) plays a crucial role. With a view to optimizing clinical use of plitidepsin, we have therefore evaluated the possibility of using JNK activation as an in vivo biomarker of response. In this study, we show that administration of a single plitidepsin dose to mice xenografted with human cancer cells does indeed lead to increased phosphorylation of JNK in tumors at 4 to 12 h. By contrast, no changes were found in other in vitro plitidepsin targets such as the levels of phosphorylated-ERK, -p38MAPK or the protein p27^KIP1. Interestingly, plitidepsin also increased JNK phosphorylation in spleens from xenografted mice showing similar kinetics to those seen in tumors, thereby suggesting that normal tissues might be useful for predicting drug activity. Furthermore, plitidepsin administration to rats at plasma concentrations comparable to those achievable in patients also increased JNK phosphorylation in peripheral mononuclear blood cells. These findings suggest that changes in JNK activity provide a reliable biomarker for plitidepsin activity and this could be useful for designing clinical trials and maximizing the efficacy of plitidepsin.  相似文献   

The influence of the herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA) on the mineralization of litter-derived alkanes and the abundance of the alkane monooxygenase gene (alkB) in the detritusphere of Pisum sativum (L.)     

Stephan Schulz  Tatiana Yuyunkina  Holger Pagel  Lukas Y. Wick  Christian Poll  Thilo Streck  Ellen Kandeler  Michael Schloter 《Biology and Fertility of Soils》2012,48(8):933-940

In the present study, the temporal and spatial variation of the abundance of the alkane monooxygenase gene alkB and 16S rRNA genes in different soil compartments was analysed in the presence or absence of 2-methyl-4-chlorophenoxyacetic acid (MCPA) after the addition of pea litter to soil in a microcosm study. Samples were analysed shortly after litter addition (T0) and 1?week (T1), 3?weeks (T3) and 6?weeks (T6) after the addition of litter. In addition also, the quantity and quality of litter-derived alkanes was analysed and measured. The results revealed a fast and complete degradation of MCPA in all compartments throughout the experiment. Nevertheless, significant changes in the distribution patterns of short- and middle-chained alkanes suggest an interaction of MCPA and alkane degradation. alkB gene copy numbers were highly influenced by the time point of analysis and by the investigated soil compartment. Overall, an increase in alkB gene copy numbers from T0 to T3 was visible in the upper soil compartments whereas a decrease compared to T0 was measured in the deeper soil compartments. MCPA addition resulted in an increase of alkB abundance at T6. Gene copy numbers of 16S rRNA were not influenced by sampling time and soil compartment. In contrast to the control treatments, a slight increase in 16S rRNA gene copy numbers was visible at T1 and T3 compared to T0 in all soil compartments.  相似文献   

A New Shift‐Share Method     

Lionel Artige  Leif van Neuss 《Growth and change》2014,45(4):667-683

Shift‐share analysis is a decomposition technique widely used in regional studies to quantify an industry‐mix effect and a competitive effect on the growth of regional employment (or any other relevant variable) relative to the national average. This technique has always been subject to criticism for its lack of theoretical basis. This paper presents a critical assessment of the methods suggested by Dunn and Esteban‐Marquillas and proposes a new shift‐share method, which separates out the two effects unambiguously. By way of illustration, we provide an application to manufacturing employment in the Belgian provinces between 1995 and 2007.  相似文献   

Distribution,structure and function of Nordic eelgrass (Zostera marina) ecosystems: implications for coastal management and conservation          下载免费PDF全文

Christoffer Boström  Susanne Baden  Anna‐Christina Bockelmann  Karsten Dromph  Stein Fredriksen  Camilla Gustafsson  Dorte Krause‐Jensen  Tiia Möller  Søren Laurentius Nielsen  Birgit Olesen  Jeanine Olsen  Leif Pihl  Eli Rinde 《水产资源保护:海洋与淡水生态系统》2014,24(3):410-434

The influence of soil organic matter fractions on aggregates stabilization in agricultural and forest soils of selected Slovak and Czech hilly lands     

Nora Polláková  Vladimír Šimanský  Miroslav Kravka 《Journal of Soils and Sediments》2018,18(8):2790-2800

  相似文献   

Chemical changes in wheat pan bread during storage and how it affects the sensory perception of aroma,flavour, and taste     

Sidsel Jensen  Henrik Oestdal  Leif H. Skibsted  Erik Larsen  Anette K. Thybo 《Journal of Cereal Science》2011

Wheat bread and whole wheat bread were stored for up to 3 weeks and specific chemical reactions were related to perceptual flavour changes as analysed by sensory profiling. Volatile and non-volatile compounds were quantified using GC–MS and HPLC. Results were examined by multivariate data analysis.  相似文献   

Inhibition of lactoperoxidase-catalyzed 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and tyrosine oxidation by tyrosine-containing random amino acid copolymers     

Clausen MR  Skibsted LH  Stagsted J 《Journal of agricultural and food chemistry》2008,56(18):8692-8698

Oxidation of 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) by lactoperoxidase was found to be inhibited by tyrosine-containing random amino acid copolymers but not by tyrosine. Both electrostatic effects and polymer size were found to be important by comparison of negatively and positively charged copolymers of varying lengths, with poly(Glu, Tyr)4:1 ([E 4Y 1] approximately 40) as the strongest competitive inhibitor (EC 50 approximately 20 nM). This polymer did not form dityrosine in the presence of lactoperoxidase (LPO) and peroxide. Furthermore, incubation with tert-butyl hydroperoxide, as opposed to hydrogen peroxide, resulted in a peculiar long lag phase of the reaction between the redox intermediate compound II and [E 4Y 1] approximately 40, indicating a very tight association between enzyme and inhibitor. We propose that interactions between multiple positively charged areas on the surface of LPO and the polymer are required for optimal inhibition.  相似文献   

Micro-scale modelling of carbon turnover driven by microbial succession at a biogeochemical interface     

Joachim Ingwersen  Christian Poll  Thilo Streck  Ellen Kandeler 《Soil biology & biochemistry》2008,40(4):864-878

The detritusphere is a very thin but microbiological highly active zone in soil. To trace the fate of litter carbon in the detritusphere we developed a new 1D dynamic mechanistic model. In a microcosm experiment soil cores were incubated with ¹³C labelled rye residues (δ¹³C=299‰), which were placed on the surface. Microcosms were sampled after 3, 7, 14, 28, 56 and 84 days and soil cores were separated into layers of increasing distance to the litter. Gradients in soil organic carbon (TOC), dissolved organic carbon (DOC), microbial biomass and activity were detected over a distance of 3 mm from the litter layer. The newly developed 1D model simulates both the total carbon and the ¹³C carbon pools and fluxes, so that it was possible to include the ¹³C data in model optimisation. The special feature of the model is that it operates with two decomposer populations; the first one is assumed to be dominated by bacteria (initial-stage decomposer) and second one by fungi (late-stage decomposer). Moreover, in the model the DOC pool is divided into two sub pools. Each DOC pool is consumed by one of the decomposer populations. After parameter optimisation the model was well suited to simulate the experimental data. The model explained 92% of the observed variance. The model output provides a comprehensive insight into the carbon cycling within the detritusphere. The simulation results showed among others that after 84 days about 10% of total litter C was transferred to the soil organic matter (SOM) pool. Only 3% was located in the microbial biomass. From the evolved CO₂ 71% was litter-derived and 29% was soil-derived. From the litter-derived CO₂, 69% was directly formed in the litter layer. The remaining 31% was transported to soil before mineralisation. Our study shows that a combination of experimental work and mathematical modelling is a powerful approach to provide a comprehensive insight into the small-scale carbon turnover in soil.  相似文献