bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of cathepsin K as a novel marker of adiposity in white adipose tissue
Authors: Chiellini Chiara , Costa Mario , Novelli Silvia E. , Amri Ez‐Zoubir , Benzi Luca , Bertacca Anna , Cohen Paul , Del Prato Stefano , Friedman Jeffrey M. , Maffei Margherita
Published: March 2003

In obesity, adipocytes undergo dramatic morphological and molecular changes associated with alterations in their gene expression profile. To identify genes differentially modulated in white adipose tissue (WAT) of obese db/db mice compared to wild type (wt) mice, we utilized RNA fingerprinting. Among the 52 candidates that we identified, we focused here on cathepsin K (ctsk), a cysteine protease, prevalently localized in lysosomes and involved in bone extracellular matrix degradation. In db/db mice, WAT ctsk mRNA was elevated 5.9‐fold, as were Mitf and TFE3 (2‐ and 3.3‐fold respectively), two transcription factors involved in ctsk induction in osteoclasts. Moreover, the level of WAT ctsk mRNA was increased in other obese models including Ay, fat, and tubby (2.8‐, 3.2‐, and 4.9‐fold respectively) and decreased in mice undergoing weight loss. Despite the ubiquitous distribution of the ctsk transcript, we demonstrated that the obesity related increase is specific to the adipocytes. Further, in vitro experiments proved that the abundance of ctsk transcript increases upon adipose conversion of the established cell line of preadipocytes 3T3‐F442A. In addition, ctsk gene expression was examined in adipose tissue of 21 lean and obese male subjects and significant correlations with BMI (r = 0.54, P = 0.012) and plasma leptin levels (r = 0.54, P = 0.015) were found. In conclusion, the WAT of obese db/db mice exhibits a different expression profile from that of the wt mice, and cathepsin K can be considered a novel marker of obesity and a target for the inhibition of adipose mass growth. © 2003 Wiley‐Liss, Inc.
Cell death regulation by the Bcl‐2 protein family in the mitochondria
Authors: Tsujimoto Yoshihide
Published: March 2003

An increase in the permeability of the outer mitochondrial membrane is central to apoptotic cell death, since it leads to the release of several apoptogenic factors, such as cytochrome c and Smac/Diablo, into the cytoplasm that activate downstream death programs. During apoptosis, the mitochondria also release AIF and endonuclease G, both of which are translocated to the nucleus and are implicated in apoptotic nuclear changes that occur in a caspase‐independent manner. Mitochondrial membrane permeability is directly controlled by the major apoptosis regulator, i.e., the Bcl‐2 family of proteins, mainly through regulation of the formation of apoptotic protein‐conducting pores in the outer mitochondrial membrane, although the precise molecular mechanisms are still not completely understood. Here, I focus on the mechanisms by which Bcl‐2 family members control the permeability of mitochondrial membrane during apoptosis. © 2003 Wiley‐Liss, Inc.
Human brain synembryn interacts with Gsα and Gqα and is translocated to the plasma membrane in response to isoproterenol and carbachol
Authors: Klattenhoff Carla , Montecino Martín , Soto Ximena , Guzmán Leonardo , Romo Ximena , de los Angeles García María , Mellstrom Britt , Naranjo José Ramón , Hinrichs María Victoria , Olate Juan
Published: March 2003

Heterotrimeric G‐proteins transduce signals from heptahelical transmembrane receptors to different effector systems, regulating diverse complex intracellular pathways and functions. In brain, facilitation of depolarization‐induced neurotransmitter release for synaptic transmission is mediated by Gsα and Gqα. To identify effectors for Gα‐proteins, we performed a yeast two‐hybrid screening of a human brain cDNA library, using the human Gαs protein as a bait. We identified a protein member of the synembryn family as one of the interacting proteins. Extending the study to other Gα subunits, we found that Gqα also interacts with synembryn, and these interactions were confirmed by in vitro pull down studies and by in vivo confocal laser microscopy analysis. Furthermore, synembryn was shown to translocate to the plasma membrane in response to carbachol and isoproterenol. This study supports recent findings in C. elegans where, through genetic studies, synembryn was shown to act together with Gqα regulating neuronal transmitter release. Based on these observations, we propose that synembryn is playing a similar role in human neuronal cells. © 2003 Wiley‐Liss, Inc.
Mouse epidermal stem cells proceed through the cell cycle
Authors: Dunnwald Martine , Chinnathambi Sathivel , Alexandrunas Dana , Bickenbach Jackie R.
Published: March 2003

The epidermis is a continuously renewing tissue maintained by undifferentiated stem cells. For decades it has been assumed that epidermal stem cells (ESCs) were held in the G0 phase of the cell cycle and that they only entered the cell cycle when needed. Previously, we showed that ESCs retained nuclear label for long periods, indicating that these cells did not proceed through the cell cycle at the same rate as the other proliferative basal cells. However, their exact cell‐cycle profile has not been determined because a pure population of ESCs has not been available. In this study, we sorted stem and transient amplifying (TA) cells from murine neonatal back skin, and adult ear, footpad, and back skin, using our recently developed method. We found that neonatal back skin had two times the number of ESCs as the adult tissues. Despite the age and anatomical difference, these ESC populations exhibited similar cell cycle profiles with approximately 96% in G0/G1 and 4% in S‐G2/M. The cell cycle profiles of the TA cells from neonatal back skin and adult footpad also showed a profile similar to each other (85% in G1 and 15% in S‐G2/M). Examination of genes on a cell cycle chip showed that proliferation associated genes and only p57 were upregulated in the TA cell and ESC population, respectively. We found BrdU positive and cyclin B1 positive cells in all groups, confirming that both ESCs and TA cells were cycling. These data demonstrate that there are more TA cells dividing than ESCs, that the cell cycle profile of adult TA cells is related to the proliferative state of the tissue in which they reside, and that ESC proceed through the cell cycle. © 2003 Wiley‐Liss, Inc.
Compartmental fasciotomy and isolating a muscle from neighboring muscles interfere with myofascial force transmission within the rat anterior crural compartment
Authors: Huijing Peter A. , Maas Huub , Baan Guus C.
Published: March 2003

Muscles within the anterior crural compartment (extensor digitorum longus, EDL; tibialis anterior, TA; and extensor hallucis longus, EHL) and within the peroneal compartment were excited simultaneously and maximally. All muscles were kept at constant length with the exception of EDL, for which muscle length was changed by moving its proximal tendon. Active and passive force was measured at proximal as well as distal EDL tendons and at the combined distal tendons of TA and EHL (TA+EHL). In the initial experimental condition, a difference (Fproximal > Fdistal) in EDL force, amounting to 0–14% of proximal force, was confirmed for most EDL lengths. This is interpreted as a clear proof of extramuscular myofascial force transmission, as no significant EDL length effects could be shown on TA+EHL force. Repeated measurements were confirmed to cause marked changes of both proximal and distal length–force characteristics, such as a shift of the whole ascending limb of the active curve, including optimum length, to higher lengths without decreasing optimum force, and decreasing active force at low lengths (by ∼57%). Repeated measurements also lowered proximal and distal EDL passive force (by up to 35%). The proximo–distal difference in passive as well as active EDL force was decreased, but persisted. At most lengths, this difference for active force amounted to a constant fraction (14%) of proximal force. TA+EHL force was not affected significantly. Subsequently, acute effects of experimental surgical alterations were studied: The first manipulation was full lateral fasciotomy of the anterior crural compartment that caused a further decrease in active force at the proximal EDL but not at the distal EDL tendon. Passive forces showed no further significant changes. The proximo–distal EDL active force difference decreased to 0–5% of proximal force. After fasciotomy, TA+EHL force increased by 30%. This was interpreted as evidence of increased intramuscular and decreased extramuscular myofascial force transmission. The second manipulation was full isolation of EDL from TA+EHL, but not from extramuscular connective tissues, which caused a further decrease of the EDL proximo–distal force differences, indicating a stiffening effect of the presence of TA+EHL on the extramuscular matrix. For EDL active force the difference was no longer significantly different from zero. In contrast, for EDL passive force the proximo–distal force difference persisted. It is concluded that extramuscular myofascial force transmission is an important feature of the anterior crural compartment. The magnitude of this force transmission requires that it be considered in analysis of muscular function. J. Morphol. 256:306–321 2003 ©2003 Wiley‐Liss, Inc.
Stomach of Aplysia depilans (Mollusca, Opisthobranchia): A histochemical, ultrastructural, and cytochemical study
Authors: Lobo‐da‐Cunha Alexandre , Batista‐Pinto Carla
Published: March 2003

We report the results of a morphological, histochemical, and cytochemical characterization of the Aplysia depilans stomach, an organ little studied in opisthobranchs. Very thin ciliated cells with microvilli on their apical surfaces are predominant in the epithelium lining the lumen of the stomach. Many lysosomes with a strong arylsulphatase activity were present in the apical regions of these cells that could also contain some lipid droplets and glycogen. Small peroxisomes were observed, usually around lipid droplets or mitochondria. Bottle‐shaped secretory cells are very common in this epithelium and produce a secretion rich in proteins and acidic mucopolysaccharides. Most of the cytoplasm of these mucus‐producing cells was filled with a very high number of granules and the nucleus is dislocated to the basal region. Cisternae of rough endoplasmic reticulum were abundant around the nucleus and several Golgi stacks were also present in this area. In spite of the variation in the electron density of the granules, only one type of secretory cell seems to be present in the stomach epithelium, since granules with very different electron densities were frequently found in the same cell. A few neurons were also found in the stomach epithelium of this species. Fibrocytes, muscle cells, nerves, and amebocytes were observed in the connective tissue of the stomach wall. J. Morphol. 256:360–370, 2003. © 2003 Wiley‐Liss, Inc.
Guidelines for using quantitative magnetization transfer magnetic resonance imaging for monitoring treatment of multiple sclerosis
Authors: Horsfield Mark A. , Barker Gareth J. , Barkhof Frederik , Miller David H. , Thompson Alan J. , Filippi Massimo
Published: March 2003

Quantitative evaluation of brain magnetic resonance imaging (MRI) scans is now an accepted part of the trial of new putative treatments for multiple sclerosis (MS). However, conventional MRI is not pathologically specific, and it does not reveal the details of the pathological processes that underlie the progression of the disease. Magnetization transfer (MT) imaging is a relatively new quantitative technique that appears to offer some pathological specificity, and can be used to monitor the changes over time in both individual lesions and the central nervous system as a whole. This paper considers the case for incorporating MT imaging into new clinical trials, so that the utility of MT for monitoring the modification of MS progression by treatment can be assessed. Specific guidelines for implementing MT imaging as part of a large multicenter clinical trial are given, and practical considerations when planning such a trial are detailed. It is anticipated that MT imaging will be incorporated into many new trials in the near future. J. Magn. Reson. Imaging 2003;17:389–397. © 2003 Wiley‐Liss, Inc.
MRI depiction of chronic intradural (subdural) hematoma in evolution
Authors: Atkinson John L.D. , Lane John I. , Aksamit Allen J.
Published: March 2003

The usual chronic subdural hematoma encountered in the elderly is actually thought to be a chronic intradural hematoma, which has been described clinically and anatomically. However, the evolution of how this chronic hematoma occurs remains enigmatic. We report the first magnetic resonance (MR) depiction of an apparent chronic intradural hematoma in evolution over several months in a 61‐year‐old man after a minimal head injury. The time delay from injury, subsequent focal pachymeningeal T1‐gadolinium enhancement, and apparent splitting of the pachymeninges by proven chronic hematoma should serve as a stimulus for further MR investigations of this interesting process. J. Magn. Reson. Imaging 2003;17:484–486. © 2003 Wiley‐Liss, Inc.
Investigation of apparent diffusion constant as an indicator of early degenerative disease in articular cartilage
Authors: Mlynárik Vladimír , Sulzbacher Irene , Bittšanský Michal , Fuiko Reinhard , Trattnig Siegfried
Published: March 2003

Purpose

To investigate the apparent diffusion constant (ADC) as a prospective magnetic resonance imaging (MRI) marker of early degeneration in articular cartilage.

Materials and Methods

Early degenerative changes were studied using in vitro MRI on cartilage‐bone specimens excised from human femoral condyles. The loss of proteoglycans developed in vivo due to a degenerative process was compared with a gadolinium diethylenetriamine pentaacetate anion (Gd‐DTPA2–) enhanced decrease of T1 relaxation times, and with an increase of ADCs and T2 relaxation times.

Results

Contrast enhanced T1 values decreased and the diffusion constants increased in cartilage regions with depleted proteoglycans. The relative changes in diffusion constants were smaller than those of Gd‐DTPA2– enhanced T1, and in some proteoglycan‐depleted regions no changes in the diffusion constants were detected. T2 relaxation times showed considerable spatial variability that did not correlate with proteoglycan concentration.

Conclusion

In contrast to Gd‐DTPA2– enhanced T1, which reflects changes in chemical composition, diffusion constants may reflect structural degradation of the cartilage matrix. J. Magn. Reson. Imaging 2003;17:440–444. © 2003 Wiley‐Liss, Inc.
Assessment of reliability in functional imaging studies
Authors: Specht Karsten , Willmes Klaus , Shah N. Jon , Jäncke Lutz
Published: March 2003

Purpose

To investigate the reliability of functional magnetic resonance imaging (fMRI), an approach for mapping and quantifying reliably activated voxels was developed.

Materials and Methods

First, a SPM99 analysis was performed, and the resulting statistical maps were taken as the basis for subsequent analyses of reliability. Several approaches were demonstrated using 1) a voxel‐wise intraclass correlation coefficient (ICC); 2) an analysis of scatter plots, calculating the correlation of contrast t‐values for pairs of activation maps; and 3) the ratio of overlapping volumes as suggested in the literature. The methods were applied to an fMRI study in which subjects were asked to vary their attentional effort during watching a flickering checkerboard pattern with varying letters in the center. The subjects had to ignore or attend to the presentation, or they had to detect a target letter within the checkerboard.

Results

The imaging data showed good reliability in terms of ICC for regions of visual processing, as well as for frontal areas, especially in the letter detection task. Furthermore, the size of reliable clusters depended on the presumed attentional effort of the subjects.

Conclusion

Application of the method demonstrated that the activation due to visual stimulation could also be detected very consistently during a no‐attend condition, but the reliability of the activations were best during the attended tasks. J. Magn. Reson. Imaging 2003;17:463–471. © 2003 Wiley‐Liss, Inc.
Multislice double inversion‐recovery black‐blood imaging with simultaneous slice reinversion
Authors: Yarnykh Vasily L. , Yuan Chun
Published: March 2003

Purpose

To develop a technique for time‐efficient multislice double inversion‐recovery (DIR) black‐blood imaging and to test its applicability and limitations for high‐resolution imaging of carotid arteries.

Materials and Methods

A multislice DIR pulse sequence with fast spin‐echo (FSE) readout was implemented on a 1.5T magnetic resonance (MR) scanner. The principle of the method is that a slice‐selective inversion in a DIR preparation reinverts an entire slice pack, and all slices are imaged within repetition time (TR). The number of slices acquired per TR (N) controls the inversion time (TI) to execute the readout for each slice at the zero‐crossing point of blood. Multislice DIR images (TR/TE = 2500/9 msec) of carotid arteries were obtained with variable N = 2–8 from four subjects. The method was compared with the standard single‐slice DIR and inflow saturation techniques.

Results

Multislice DIR with N = 2–6 provided similar flow suppression in carotid arteries as single‐slice DIR. At all N = 1–8, blood suppression by DIR was significantly better than by inflow saturation. An additional limitation of multislice DIR was saturation of the signal from stationary tissues that worsened visualization of the vessel wall at N ≥ 6.

Conclusion

Multislice DIR provides up to eight‐fold improvement of time‐efficiency relative to single‐slice DIR and high‐quality blood suppression. J. Magn. Reson. Imaging 2003;17:478–483. © 2003 Wiley‐Liss, Inc.
Effects of the North Atlantic oscillation on the probability for climatic categories of local monthly rainfall in southern Spain
Authors: Muñoz‐Díaz D. , Rodrigo F. S.
Published: March 2003

In many regions of the world, planning agricultural and water management activities is usually done based on probabilities for seasonal or monthly rainfall, for specified intervals of values. These intervals of rainfall amounts are commonly grouped into three categories: drought, normal rainfall, and abundant rainfall. Changes in the probabilities of occurrence of rainfall amounts within these climatic rainfall categories will influence the decisions that farmers and water managers will take. This research explores the changes produced by the North Atlantic oscillation (NAO) on the probability that local monthly rainfall takes in the southern Iberian Peninsula. The evolution of the NAO was divided into three phases: negative NAO, ‘normal’ NAO, and positive NAO, and local rainfall series were divided into three groups, corresponding to each NAO phase. The resulting empirical distribution functions were analysed and modelled by Gamma distributions. The results allow one to estimate the change in the probabilities of wet and dry months when a change in NAO phase is produced. The main result of this work is that changes in the probability of occurrence of climate categories of rainfall are more complex than only an increase of rainfall amount during the negative NAO phase and a decrease during the positive NAO phase. In fact, a certain asymmetry is detected in January, with more extremes linked to the negative NAO phase. Copyright © 2003 Royal Meteorological Society
The ‘Montserrat‐2000’ flash‐flood event: a comparison with the floods that have occurred in the northeastern Iberian Peninsula since the 14th century
Authors: Llasat María del Carmen , Rigo Tomeu , Barriendos Mariano
Published: March 2003

This paper presents an analysis of the flash floods that occurred in Catalonia (NE Iberian Peninsula) on 10 June 2000, in the context of the historical floods recorded since the 14th century. The study starts with pluviometric and meteorological analyses (essentially synoptic and thermodynamic) of the episode. There follows a comparison of this event with previous floods for which we have instrumental information, information from archives, or both types of information. In some cases this permitted us to make a meteorological comparison of episodes similar to that of June 2000, and the complete series was used to carry out a frequency analysis of floods that have occurred in the basin under study. The conclusions show that although catastrophic flooding in spring is not as typical a phenomenon as autumn flooding, such floods have been recorded at least once each century, and it can be stated that the synoptic meteorological situation, where recorded, showed similar characteristics in all cases. Copyright © 2003 Royal Meteorological Society
Preferential flow and aging of NAPL in the unsaturated soil zone of a hazardous waste site: implications for contaminant transport
Authors: Totsche Kai U. , Kögel‐Knabner Ingrid , Haas Bettina , Geisen Stefan , Scheibke Rainer
Published: March 2003

Flow of non‐aqueous phase liquids (NAPL) in the unsaturated zone is thought to be driven by gravity with a dominant vertical flow direction, and lateral spreading to be limited to the gradient of the relative permeabilities. The effect of soil profile build‐up, preferential flow, aging, and groundwater level fluctuations is mostly neglected. The objective of our study was to check the effects of such processes on the fate of NAPL in the unsaturated soil zone. At a hazardous waste site, we conducted a field survey of the unsaturated soil zone and monitored the groundwater for a two year period. We conducted spatially resolved and depth dependent soil sampling and analysis and the evaluation of former ram and core drilling protocols. The samples were analyzed for the 16 EPA PAH and alkanes with GC‐MS and GC‐FID. 13C‐NMR spectroscopy was used to assess structural changes of the NAPL phase. Flow of bulk NAPL along macropores and along preferential permeability structures, like sedimentation discontinuities, are the dominant transport pathways which cause large lateral spreading beyond those expected by the relative permeability gradient. Accumulation of NAPL was found at locations with abrupt textural changes and within the zone of capillary rise. Aging of NAPL results in the depletion in soluble and volatile compounds but also in oxidation and polymerization. It increases the chemical diversity and decreases the mobility of the NAPL. Thus, NAPL flow ceases much earlier than expected from the capillary forces. As chemical transformation is restricted to the NAPL water/air interface, a skin‐like thin film is formed which encapsulates and preserves the bulk NAPL from further hardening, limiting contaminant mass transfer from the NAPL to the aqueous phase.
Estimating water retention curves of forest soils from soil texture and bulk density
Authors: Teepe Robert , Dilling Hermann , Beese Friedrich
Published: March 2003

Forest soils differ significantly from the arable land in their distribution of the soil bulk density and humus content, but the water retention parameters are primarily derived from the data of agricultural soils. Thus, there is a need to relate physical parameters of forest soils with their water retention characteristics and compare them with those of agricultural soils. Using 1850 water retention curves from forest soils, we related the following soil physical parameters to soil texture, bulk density, and C content: air capacity (AC), available water capacity (AWC), and the permanent wilting point (PWP). The ACs of forest soils were significantly higher than those of agricultural soils which were related to the low bulk densities of the forest soils, whereas differences in AWCs were small. Therefore, for a proper evaluation of the water retention curves (WRCs) and the parameters derived from them, further subdivisions of the lowest (< 1.45 g cm‐3) of the three bulk density classes was undertaken to the wide range of low soil densities in forest soils (giving a total of 5 bulk density classes). In Germany, 31 soil texture classes are used for the estimation of soil physical parameters. Such a detailed classification is not required because of insignificant differences in WRCs for a large number of these classes. Based on cluster analysis of AC, AWC, and PWP parameters, 10 texture collectives were obtained. Using 5 classes of bulk densities, we further calculated the ACs, AWCs, and the PWPs for these 10 classes. Furthermore, “van Genuchten parameters” (θ r, θ s, α, and n) were derived which described the average WRC for each designated class. In a second approach using multiple regression analysis, regression functions for AC, AWC, and PWP and for the van Genuchten parameter were calculated.
Organische Substanz und Benetzbarkeit von Bodenproben ‐ eine Interpretation
Authors: Ellies Achim , Hartge Karl Heinrich , MacDonald Roberto , Ramirez Carlos
Published: March 2003

An je vier Standorten vulkanischer oder Anteile vulkanischer Aschen enthaltender Böden unter Wald‐ und unterWeidenutzung wurden aus den A‐Horizonten Aggregate mit 4—6 und 10—12 mm Größe entnommen und durch Schälen in die Bereiche Kern und Schale aufgeteilt. Mit der ausgesiebten Fraktion 38—63 μm wurden auf Objektträgern Körnerpräparate hergestellt und die Benetzungswinkel mit Tropfen gesättigter KCl‐Lösung gemessen. An allen Gruppen wurde der Anteil an organischer Substanz bestimmt. Die Benetzungswinkel stiegen stets mit zunehmendem Anteil an organischer Substanz, unabhängig von der Art der Aufteilung in Gruppen (Nutzung, Alter und Anteil der vulkanischen Mineralkomponente, Aggregatgröße, —bereich und Entnahmetiefe). Die Beziehungen waren auch bei höherer Signifikanz niemals eng (r ∼ 0, 5). Ursachen für die Steigung sind der Mengenanteil separater organischer Partikel sowie Anteile und Ausprägung von Filmen auf Mineralteilchen. Benetzungswinkel in Böden sind Summeneffekte dieser beiden Parameter.
Proton release by N2‐fixing plant roots: A possible contribution to phytoremediation of calcareous sodic soils
Authors: Qadir Manzoor , Steffens Diedrich , Yan Feng , Schubert Sven
Published: March 2003

With a world‐wide occurrence on about 560 million hectares, sodic soils are characterized by the occurrence of excess sodium (Na+) to levels that can adversely affect crop growth and yield. Amelioration of such soils needs a source of calcium (Ca2+) to replace excess Na+ from the cation exchange sites. In addition, adequate levels of Ca2+ in ameliorated soils play a vital role in improving the structural and functional integrity of plant cell walls and membranes. As a low‐cost and environmentally feasible strategy, phytoremediation of sodic soils — a plant‐based amelioration — has gained increasing interest among scientists and farmers in recent years. Enhanced CO2 partial pressure (PCO2) in the root zone is considered as the principal mechanism contributing to phytoremediation of sodic soils. Aqueous CO2 produces protons (H+) and bicarbonate (HCO3‐). In a subsequent reaction, H+ reacts with native soil calcite (CaCO3) to provide Ca2+ for Na+ Ca2+ exchange at the cation exchange sites. Another source of H+ may occur in such soils if cropped with N2‐fixing plant species because plants capable of fixing N2 release H+ in the root zone. In a lysimeter experiment on a calcareous sodic soil (pHs = 7.4, electrical conductivity of soil saturated paste extract (ECe) = 3.1 dS m‐1, sodium adsorption ratio (SAR) = 28.4, exchangeable sodium percentage (ESP) = 27.6, CaCO3 = 50 g kg‐1), we investigated the phytoremediation ability of alfalfa (Medicago sativa L.). There were two cropped treatments: Alfalfa relying on N2 fixation and alfalfa receiving NH4NO3 as mineral N source, respectively. Other treatments were non‐cropped, including a control (without an amendment or crop), and soil application of gypsum or sulfuric acid. After two months of cropping, all lysimeters were leached by maintaining a water content at 130% waterholding capacity of the soil after every 24±1 h. The treatment efficiency for Na+ removal in drainage water was in the order: sulfuric acid > gypsum = N2‐fixing alfalfa > NH4NO3‐fed alfalfa > control. Both the alfalfa treatments produced statistically similar root and shoot biomass. We attribute better Na+ removal by the N2‐fixing alfalfa treatment to an additional source of H+ in the rhizosphere, which helped to dissolve additional CaCO3 and soil sodicity amelioration.
Carbon allocation in a sweet sorghum‐soil system using 14C as a tracer
Authors: Fernández Jesús , Curt M. Dolores , Aguado Pedro , Magro Enrique
Published: March 2003

Carbon (C) distribution in a sweet sorghum‐soil system was studied by 14CO2 pulse‐labeling of shoots at three dates during the growth cycle in order to assess the contribution of the crop to carbon storage in the soil. Soil and plant samplings were performed 24 h after the 14C‐labeling and at final harvest (October) to determine the assimilate allocation and estimate the amount of plant‐derived soil carbon. Approximately 4‐16% of the 14C present in the sorghum‐soil system was located in the soil fine fraction (< 2 mm) over a 24 h period. At final harvest, the proportion of 14C in the soil accounted for 7‐9% of the 14C present in the sorghum‐soil system. The plant‐derived soil carbon was estimated at 0.10‐0.12 g C plant‐1 day‐1. The total amount of carbon captured by sweet sorghum was estimated at 1.44 kg C m‐2 over the whole growth cycle: 0.82 kg C m‐2 in the above‐ground biomass, 0.52 kg C m‐2 in the below‐ground biomass and 0.10 kg C m‐2 in the soil carbon pool. No significant increase in soil 14C was detected over the next 14 months.
Changes in soil properties and humic substances after long‐term amendments with manure and crop residues in dryland farming systems
Authors: Dorado José , Zancada María‐Cristina , Almendros Gonzalo , López‐Fando Cristina
Published: March 2003

After 16 years of periodical applications of either farmyard manure or crop wastes at two levels of mineral N fertilization to a Calcic Haploxeralf in the semiarid central Spain, we found significant changes in chemical fertility levels and in the concentration, chemical composition, and carbon mineralization rates of soil organic matter (SOM). The changes in SOM quality were related to significant improvements of soil physical properties, mainly aggregate stability and water retention. Such changes were related to the increased concentration of humic colloids in soil, the mineral N dose, and the type of organic matter applied. When compared with the control plots, the organic matter accumulated in the amended plots tended to be less transformed, and its total concentration and humification degree decreased with increasing external N‐inputs. Humic acids from the amended plots showed a more marked aliphatic character (mainly after N addition) than those from control plots. Farmyard manure led to a significant improvement of soil physical properties, but had a comparatively small effect in promoting biodegradation and humification of crop wastes. This could be due to the high biological stability of the manure used which, in semiarid Mediterranean fields, usually leads to an accumulation of little transformed SOM.
Aeration effects on CO2, N2O, and CH4 emission and leachate composition of a forest soil
Authors: Vor Torsten , Dyckmans Jens , Loftfield Norman , Beese Friedrich , Flessa Heiner
Published: March 2003

The availability of O2 is one of the most important factors controlling the chemical and biological reactions in soils. In this study, the effects of different aeration conditions on the dynamics of the emission of trace gases (CO2, N2O, CH4) and the leachate composition (NO3‐, DOC, Mn, Fe) were determined. The experiment was conducted with naturally structured soil columns (silty clay, Vertisol) from a well aerated forest site. The soil monoliths were incubated in a microcosm system at different O2 concentrations (0, 0.001, 0.005, 0.01, 0.05, and 0.205 m3 m‐3 in the air flow through the headspace of the microcosms) for 85 days. Reduced O2 availability resulted in a decreased CO2 release but in increased N2O emission rates. The greatest cumulative N2O emissions (= 1.6 g N2O‐N m‐2) were observed at intermediate O2 concentrations (0.005 and 0.01 m3 m‐3) when both nitrification and denitrification occurred simultaneously in the soil. Cumulative N2O emissions were smallest (= 0.05 g N2O‐N m‐2) for the aeration with ambient air (O2 concentration: 0.205 m3 m‐3), although nitrate availability was greatest in this treatment. The emission of CH4 and leaching of Mn and Fe were restricted to the soil columns incubated under completely anoxic conditions. The sequence of the reduction processes under completely anoxic conditions complied with the thermodynamic theory: soil nitrate was reduced first, followed by the reduction of Mn(IV) and Fe(III) and finally CO2 was reduced to CH4. The re‐aeration of the soil columns after 85 days of anoxic incubation terminated the production of CH4 and dissolved Fe and Mn in the soil but strongly increased the emission rates of CO2 and N2O and the leaching of NO3‐ probably because of the accumulation of DOC and NH4+ during the previous anoxic period.
Nitrous oxide emission from frozen grassland soil and during thawing periods
Authors: Müller C. , Kammann C. , Ottow J. C. G. , Jäger H.‐J.
Published: March 2003

Nitrous oxide (N2O) was emitted during a frost period from an old grassland as well as during thawing. Soil incubations at various times throughout the freezing period showed that highest emission rates were emitted around 0 °C, and the magnitude of the emission peak increased with the length of the freezing period. Highest N2O emissions during freezing and thawing were measured from soil previously treated with nitrate (NO3‐). The emitted N2O was produced via reduction of NO3‐. The steady drop in N2O emission at soil temperatures higher than 2 °C coincided with large dinitrogen (N2) emissions which most likely reflected the increasing enzymatic activity of N2O reductase with increasing temperatures. Measurements of mineral N concentrations showed that NO3‐ and NH4+, which were shortly after fertilizer application immobilized into the microbial biomass, became partly available again through the freezing effect and caused large N2O emissions in winter. This study provided evidence that N2O emissions during freezing and thawing in the winter are due to biological rather than chemical activity in soil.
Effectiveness of an elemental sulfur fertilizer in an oilseed‐cereal‐legume rotation on the Canadian prairies
Authors: Wen Guang , Schoenau Jeff J. , Mooleki S. Patrick , Inanaga Shinobu , Yamamoto Tahei , Hamamura Kunio , Inoue Mitsuhiro , An Ping
Published: March 2003

Adequate sulfur (S) nutrition is critical for sustaining yields in crop rotation systems. Because of slow oxidation of elemental S (S°), research on S° fertilizers has emphasized improving the short‐term availability, while the long‐term effects of S° have been overlooked. The effectiveness of a dispersible granule S° fertilizer (SF: Sulfer95), consisting of S° particles smaller than any S° fertilizer reported in literature (< 44 μm in diameter), was compared to gypsum (CS: CaSO4) and ammonium sulfate [AS: (NH4)2SO4] in a three‐year experiment (1997—1999) on a moderately S deficient Black Chernozem soil (Typic Cryoboroll). The three S fertilizers were applied to canola (Brassica rapaL.) at 20, 40, and 80 kg S ha‐1, supplemented with corresponding rates of nitrogen (N) fertilizer in the first year. The control treatment (CT) received N only. Barley (Hordeum vulgareL.) and peas (Pisum sativumL.) were grown in the second and third years to test the availability of residual S. Although the yield of canola in SF fertilized treatments was only slightly higher than in CT, available S provided by SF produced a higher physiological S efficiency (PSE). Superior yields with residual SF were obtained in the second and third years by barley and peas at the rate of 80 kg S ha‐1applied in the first year, indicating that slow oxidation of SF was beneficial to the crops subsequently grown. Over three years, the total crop S uptake was 21, 4.0, and 15% higher with SF than with CT, CS, and AS, respectively.
Rice yield gaps in irrigated systems along an agro‐ecological gradient in West Africa
Authors: Becker Mathias , Johnson David E. , Wopereis Marco C. S. , Sow Abdoulaye
Published: March 2003

Irrigated rice (Oryza sativa L.) in West Africa covers about 12 % of the regional rice‐growing area, and is produced all along the agro‐ecological gradient from the forest zone to the Sahara desert margins. Spatial and temporal variability of yield gaps (i.e., difference between actual and potential yield) were determined to set priorities for research and target technologies. On‐farm trials were conducted on 191 irrigated lowland fields in the humid forest, the savanna and the Sahel. Farmers' yields were compared with those of super‐imposed treatments of improved fertilization and weed management. Farmers' yields varied between 0.2 and 8.7 Mg ha‐1, with average yields of 3.4 Mg ha‐1 (Guinea savanna), 3.6 Mg ha‐1 (humid forest), 3.9 Mg ha‐1 (Sahel), and 5.1 Mg ha‐1 (Sudan savanna). Simulated potential yields increased from 7 Mg ha‐1 in the forest to about 10 Mg ha‐1 in the Sahel. Accordingly, yield gaps were large, ranging from 3.2 to 5.9 Mg ha‐1. Researcher weed control in the Sahel gave grain yield increases of about 1.0 Mg ha‐1. Improved weed and N fertilization management increased yields by 1 to 2 Mg ha‐1 in the forest and Guinea savanna sites. A share of 57‐80 % of the yield gap could not be accounted for. Improving weed control is likely to have the highest pay‐off in the Sahel while improved management of fertilizer N will be most beneficial in the forest and savanna environments.
The effect of soil flooding on the transformation of Fe oxides and the adsorption/desorption behavior of phosphate
Authors: Zhang Yongsong , Lin Xianyong , Werner Wilfried
Published: March 2003

As repeatedly reported, soil flooding improves the availability of P to rice. This is in contrast with an increased P sorption in paddy soils. The effects of soil flooding on the transformation of Fe oxides and the adsorption/desorption of P of two paddy soils of Zhejiang Province in Southeast‐China were studied in anaerobic incubation experiments (submerging with water in N2 atmosphere). Soil flooding significantly increased oxalate‐extractable Fe (Feox), mainly at the expense of dithionite‐soluble Fe (FeDCB), as well as oxalate‐extractable P (Pox), but decreased the ratio of Pox/Feox. Flooding largely increased both, P adsorption and the maximum P adsorption capacity. The majority of newly sorbed P in the soils was Pox, but also more newly retained P was found to be not extractable by oxalate. Flooding also changed the characteristics of P desorption in the soils. Due to a decrease of the saturation index of the P sorption capacity, P adsorbed by flooded soils was much less desorbable than that from non‐flooded soils. There are obviously significant differences in the nature of both, the Feox and Pox fractions under non‐flooded and flooded conditions. The degree of the changes in Feox, Pox, P adsorption and P desorption by flooding depended on the contents of amorphous and total Fe oxides in non‐flooded soils. Our results confirm that the adsorption and desorption behavior of P in paddy soils is largely controlled by the transformation of the Fe oxides. The reasons of the often‐reported improved P availability to rice induced by flooding, in spite of the unfavorable effect on P desorbability, are discussed.
Varietal tolerance to Zinc deficiency in wheat and barley grown in chelatorbuffered nutrient solution and its effect on uptake of Cu, Fe, and Mn
Authors: Lombn�s Peder , Singh Bal Ram
Published: March 2003

Tolerance to zinc (Zn) deficiency was examined for three wheat (Triticum aestivum L.) and three barley (Hordeum vulgare L.) varieties grown in chelator‐buffered nutrient solution. Four indices were chosen to characterize tolerance to Zn deficiency: (1) relative shoot weight at low compared to high Zn supply (“Zn efficiency index”), (2) relative shoot to root ratio at low compared to high Zn supply, (3) total shoot uptake of Zn under deficient conditions, and (4) shoot dry weight under deficient conditions. Barley and wheat exhibited different tolerance to Zn deficiency, with barley being consistently more tolerant than wheat as assessed by all four indices. The tolerance to Zn deficiency in the barley varieties was in the order Thule=Tyra>Kinnan, and that of wheat in the order Bastian=Avle>Vinjett. The less tolerant varieties of both species accumulated more P in the shoots than the more tolerant varieties. For all varieties, the concentrations of Mn, Fe, Cu, and P in shoot tissue were negatively correlated with Zn supply. This antagonism was more pronounced for Mn and P than for Cu and Fe. Accumulation of Cu in barley roots was extremely high under Zn‐deficient conditions, an effect not so clearly indicated in wheat.
Effect of cropping systems on phosphatases in soils
Authors: Dodor Daniel E. , Tabatabai M. Ali
Published: March 2003

Phosphatases are widely distributed in nature and play a major role in phosphorus nutrition of plants. The effects of crop rotations and nitrogen fertilization on the activities of phosphatases (acid phosphatase, alkaline phosphatase, and phosphodiesterase) were studied in soils from two long‐term cropping systems at the Northeast Research Center (NERC) in Nashua and the Clarion Webster Research Center (CWRC) in Kanawha, Iowa, USA. Surface soils (0—15 cm) were taken in 1996 and 1997 from replicated field plots in corn, soybeans, oats, or meadow (alfalfa) that received 0 or 180 kg N ha—1 before corn. Because of differences in organic C contents among soils of the two sites, the soils from the CWRC sites contained greater enzyme activity values than those from the NERC site. Plots under oats or meadow showed the greatest activity values, whereas those under continuous corn at the CWRC site and soybean at the NERC site showed the least activities. Analysis of variance indicated that the activities of the phosphatases were significantly affected by crop rotation (P < 0.001) in both years at the NERC site but not at the CWRC site. Nitrogen fertilization affected the activity of acid phosphatase in soils from the CWRC site in both years and alkaline phosphatase only in 1997; but it did not affect the activities of the phosphatases in the soils from the NERC site. With the exception of alkaline phosphatase (CWRC) and phosphodiesterase (NERC) in soils sampled in 1997, activities of alkaline phosphatase and phosphodiesterase were significantly correlated with microbial biomass C (C mic) in soils from both sites and years, with r values ranging from 0.366* to 0.599***. Cropping systems and N fertilization affected the specific activities of phosphomonoesterases, especially acid phosphatase, but not of phosphodiesterase. Regression analysis showed that activities of phosphatases were significantly correlated with organic C contents of soils from the NERC site but not from the CWRC site.
Fate of heavy metals in a strongly acidic shooting‐range soil: small‐scale metal distribution and its relation to preferential water flow
Authors: Knechtenhofer Lars A. , Xifra Irene O. , Scheinost Andreas C. , Flühler Hannes , Kretzschmar Ruben
Published: March 2003

To assess the mobility of Pb and associated metals in a highly contaminated shooting range soil (Losone, Ticino, Switzerland), we investigated the spatial distribution of the metals and their relation to preferential water flow paths. A 2.2 m2 plot located 40 m behind the stop butt was irrigated with a solution containing bromide and Brilliant Blue, a slightly sorbing dye. A soil profile 50 cm in width was sampled down to 80 cm with a spatial resolution of 2.5 cm, resulting in 626 samples. Concentrations of elements (12 ≤ Z ≤ 92) were determined by energy‐dispersive Xray fluorescence spectrometry, and Brilliant Blue concentrations were determined with a chromameter. In the acidic (pH 3), organic matter‐rich, well drained Dystric Cambisol, maximum concentrations of 80.9 g kg‐1 Pb, 4.0 g kg‐1 Sb, and 0.55 g kg‐1 Cu were measured in the topsoil. Within 40 cm soil depth, however, Pb, Sb, and Cu approached background concentrations of 23 mg kg‐1, 0.4 mg kg‐1, and 9.4 mg kg‐1, respectively. The even horizontal distribution and the steep gradient along soil depth indicate tight metal binding in the topsoil, and a fairly homogeneous transport front. In contrast, water flow through the profile was highly heterogeneous. In the uppermost 20 cm, preferential flow was initiated by heterogeneous infiltration at the soil surface, but had no influence on metal distribution. Below 20 cm, however, preferential flow originated from larger tree roots, and metal concentrations were significantly elevated along these macropores. Spatial distributions of Pb, Sb, and Cu were similar, suggesting that all three metals are strongly retained in the topsoil and transported along preferential water flow paths in the subsoil.
Persistent organic pollutant concentrations in air‐ and freeze‐dried compared to field‐fresh extracted soil samples of an eastern Slovak deposition gradient
Authors: Wilcke Wolfgang , Krauss Martin , Barančíková Gabriela
Published: March 2003

Sample preparation affects the results of the determination of persistent organic pollutant (POP) concentrations in soils. We compared the extraction results of POPs from air‐ and freeze‐dried with field‐fresh samples. We determined the concentrations of 21 polycyclic aromatic hydrocarbons (PAHs) and 14 polychlorinated biphenyls (PCBs) in 35 horizons of forest soils (Lithosols and Cambisols) along a deposition gradient caused by a chemical factory in Strážske (eastern Slovakia). The organic C (Corg) concentrations of the studied samples ranged 14‐477 g kg‐1, the sum of 21 PAH (Σ 21PAHs) concentrations 53‐6870 μg kg‐1, and that of 14 PCBs (Σ 14PCBs) 0.12 96 μg kg‐1. The benzofluoranthenes were the most abundant PAHs, and the hexa‐chlorinated PCBs 138 and 153 were the most abundant PCBs. The deposition gradient was reflected by decreasing PAH and PCB storages in the organic layer with increasing distance from the chemical factory (Σ 21PAHs: 82‐238, Σ 14PCBs: 0.34‐2.3 g ha‐1). The PAH concentrations in air‐ and freeze‐dried samples were consistently lower than those in field‐fresh extracted samples. For naphthalene, this was mainly attributable to volatilization losses during drying. Naphthalene losses decreased with increasing Corg concentrations. For all other PAHs, drying reduced the extractability; the latter was correlated with the water content of the samples. The differences in most PCB concentrations among the sample preparation methods were small (within the determination error of ±15 %) and inconsistent. However, PCBs 8, 28, 52, and 209 had markedly higher concentrations in dried than in fieldfresh extracted samples. The increased recovery of low‐chlorinated PCBs in dried samples may be explained by redistribution of PCBs from higher to lower contaminated samples via the drying room atmosphere because there were no PCBs in analytical blanks. This assumption is supported by a close correlation between the octanol‐air distribution coefficient and the up to hexa‐chlorinated PCB concentrations (normalized to those in field‐fresh extracted samples) in air‐ (r = ‐0.90) and freeze‐dried (r = ‐0.86) samples. Our study shows that each sample preparation method has its specific advantages and disadvantages. Sample drying results in a standardization to a well‐defined water content and facilitates homogenization; therefore it increases the reproducibility of POP determinations. Extraction of field‐fresh samples reduces volatilization losses and contamination risks.