bluuebunny/crossref_metadata_2025_split huggingface dataset:
Life strategies and spatial arrangement of grasses in a Mediterranean ecosystem in Greece
Authors: Dalaka A. , Sgardelis S. 
Published: August 2006

AbstractThe temporal and spatial distribution, and the life strategies, of fifteen grass species in a Mediterranean evergreen sclerophyllous formation at Petralona (Chalkidiki, Greece) were studied in order to identify the relationships between species, and among species and the environment, which allows for the coexistence of species.The grass species were grouped into (i) early annual species that were characterized by early germination and a relatively long growth period; they did not need excessive resources and were distributed over the entire site, (ii) late annuals that were characterized by late germination and a short growth period; they required resources within this limited period and were competitive in capturing them and so were confined to the most productive sites of the site and (iii) perennial grasses that were characterized by early germination and vegetative reproduction; they were tolerant to nutrient shortages and hence maintained their distribution on the site.The spatial arrangement of species can be considered as a response to the selective pressures of the seasonal water and resource availability in a Mediterranean environment. This environment posed temporal limitations on the activity of early annual and late annual species, which restricts them in time and space. The perennial species overcame this by being flexible in their resource capture and use, because of their ability to store nutrients.
Performance and environmental effects of forage production on sandy soils. V. Impact of grass understorey, slurry application and mineral N fertilizer on nitrate leaching under maize for silage
Authors: Wachendorf M. , Büchter M. , Volkers K.C. , Bobe J. , Rave G. , Loges R. , Taube F. 
Published: August 2006

AbstractA field experiment with maize for silage was conducted to assess the effects of mineral nitrogen (N) fertilizer application rates (0, 50, 100, 150 kg ha−1), slurry application rates (0, 20, 40 m3 ha−1) and the use of an understorey with perennial ryegrass on nitrate (NO3)‐leaching losses. Leachate was collected using ceramic suction cups. Soil mineral N (SMN) was determined to a depth of 90 cm at the end of the growing season. Higher levels of N supply with mineral fertilizer or slurry resulted in higher leaching losses. The grass understorey significantly reduced the losses. The amount of N lost to the groundwater was positively related to SMN at the end of the growing season, with leaching losses representing less than 0·45 of SMN on average. Leaching losses were positively related to the N surplus, which was calculated from the difference between N input (N from fertilizer, slurry and atmospheric deposition) and N output (N removed with maize herbage mass and bound in the understorey biomass in spring). In view of the large variation in weather conditions between the experimental years, it is suggested that for the sandy soils in this experiment N‐leaching losses under maize can be estimated satisfactorily from SMN and the calculated N surplus.
Performance and environmental effects of forage production on sandy soils. IV. Impact of slurry application, mineral N fertilizer and grass understorey on yield and nitrogen surplus of maize for silage
Authors: Wachendorf M. , Volkers K. C. , Loges R. , Rave G. , Taube F. 
Published: August 2006

AbstractA field experiment was conducted from 1998 to 2001 to measure the performance and environmental effects of a maize crop (Zea mais L.) in a continuous production system with and without a grass understorey (Lolium perenne L.), with varied N inputs. The experiment was located on a sandy soil in northern Germany and comprised all combinations of slurry application rate (0, 20, 40 m3 ha−1) and mineral N fertilizer (0, 50, 100, 150 kg N ha−1). Understorey treatments included maize with and without perennial ryegrass. Net energy (NEL) yield of maize increased with mineral N application rate but reached a plateau at high rates. Increase in yield of dry matter because of mineral N fertilizer was lower with increased slurry application rate. Neither slurry and mineral N application nor a grass understorey affected NEL concentration of maize, whereas crude protein (CP) concentration increased with increase in application of slurry and mineral N fertilizer. Nitrogen supply by slurry or mineral fertilizer had no effect on the amount of N in the grass understorey after the harvest of maize. The average amount of N bound annually in the understorey was 60 kg N ha−1. The reduced biomass of the understorey because of enhanced maize competition was compensated for by an increased CP concentration in the grass. The grass understorey affected the NEL yield of maize negatively only at very low levels of N input but increased the N surplus at all levels.
Diurnal and seasonal patterns of leaf gas exchange in bahiagrass (Paspalum notatum Flügge) growing in a subtropical climate
Authors: Ribeiro R. V. , Lyra G. B. , Santiago A. V. , Pereira A. R. , Machado E. C. , Oliveira R. F. 
Published: August 2006

AbstractThe objective of this study was to evaluate the seasonal and diurnal changes in leaf gas exchange in bahiagrass (Paspalum notatum) plants grown in an irrigated lawn. Carbon dioxide assimilation, transpiration, stomatal conductance, leaf temperature and leaf‐to‐air vapour pressure difference were measured during the daylight period from April 2003 to March 2004. The monitored environmental variables were photosynthetic photon flux density, air temperature, air relative humidity, photoperiod and sunshine rate. Factor and cluster analyses were used to select variables and to group months with similar physiological and meteorological characteristics, and three distinct periods were identified: (i) May to July: with low energetic availability, low leaf temperatures and low photosynthetic activity; (ii) September to January: with high energetic availability, high leaf temperatures and high photosynthetic activity; and (iii) April–March–August: a transient period with environmental and physiological characteristics showing intermediate values. The reduced plant development and growth during the winter season was in accordance to the lower photosynthetic activity recorded from June to August, this variable being a potential indicator of reduced phytomass production. The relationships between leaf gas exchange and seasonal growth are discussed.
Scaling up of a mechanistic dynamic model in a GIS environment to model temperate grassland production at the regional scale
Authors: Gimona A. , Birnie R. V. , Sibbald A. R. 
Published: August 2006

AbstractRegional‐scale ecological processes are mediated by processes occurring at local scales. Spatially explicit models are needed to understand the broad‐scale consequences of a large number of local processes, driven by factors which are heterogeneous at a broad scale. A Geographic Information System (GIS)‐based mechanistic model, which can be used as a flexible tool to investigate the regional‐scale effects of changes in environmental factors on herbage production from aLolium perennesward, was developed and used to investigate the consequences of aggregating driving variables at different resolutions. The model allows rigorous scaling up of previously existing field‐based modelling approaches within a GIS context. The model's mechanistic approach allows flexibility in the simulation of the separate effects of environmental driving variables and of cutting regimes. The driving variables (temperature, solar radiation, available soil moisture and soil nitrogen status) are scaled up using geostatistical techniques. The model is used to evaluate weekly changes in herbage production under environmental conditions, variable both in space and time, under different cutting regimes. It is shown that, in this model, aggregation at 1 km2is a good compromise between accuracy and practical feasibility, and that, while ignoring heterogeneity over many square kilometres can induce large errors, their magnitude and direction also depend on the model response curve to an input variable. The results obtained were consistent with the known trends in influential environmental factors. The programming within a GIS makes the model flexible in its application and, therefore, makes it easy to apply at a variety of scales.
Effects of plant age, experimental nutrient addition and ant occupancy on herbivory in a neotropical myrmecophyte
Authors: TRAGER MATTHEW D. , BRUNA EMILIO M. 
Published: August 2006

SummaryVariation in antiherbivore defences among individuals within a plant species may be influenced by intrinsic characteristics of the plant, environmental conditions and the interactions between these factors.We used a long‐term field experiment and a laboratory palatability trial to elucidate the effects of plant age, nutrient availability and ant occupancy on herbivore damage sustained byCordia alliodora, a common neotropical myrmecophyte.Herbivory in this system was influenced by both plant characteristics and environmental conditions, and the relative importance of these variables changed with plant age.Five‐year‐old plants had a higher frequency of ant occupation and more workers per domatium than 1‐year‐old plants.Plant age did not significantly affect herbivory in either field studies or laboratory palatability trials conducted with a specialist herbivore. In the field, however, 1‐year‐old plants tended to have higher levels of herbivory than 5‐year‐old plants.There was a trend towards lower herbivory in trees that had been fertilized. Additionally, leaves from fertilized trees were significantly less palatable to specialist herbivores.In 1‐year‐old plants, the abundance of ants in domatia had no effect on herbivory of nearby leaves. In contrast, ant abundance and herbivory were negatively correlated for 5‐year‐old trees, demonstrating that ants provide effective defence only for older plants.These results suggest that understanding ant‐plant‐herbivore relationships requires examining how biotic and abiotic factors and their interactions change with plant ontogeny. Although our work focused on one particular ant‐plant system, the importance of ontogenetic variation in antiherbivore defence is increasingly recognized as a critical area of study in plant defence theory.
Plasmacytoid Dendritic Cells Induce a Distinct Cytokine Pattern in Virus‐Specific CD4+ Memory T Cells that is Modulated by CpG Oligodeoxynucleotides
Authors: Farkas L. , Kvale E. O. , Lund‐Johansen F. , Jahnsen F. L. 
Published: August 2006

AbstractInherent properties of dendritic cell (DC) subsets are important in the regulation of naïve T‐cell differentiation (e.g. Th1 versus Th2 cells), whereas effector memory T cells are believed to produce a fixed cytokine repertoire independent of the type of antigen presenting cell. Here we show that two distinct human DC subsets, plasmacytoid DC (PDC) and myeloid CD11c+ DC, induced autologous mumps virus‐specific memory CD4+ T cells to produce markedly different cytokine patterns upon antigen stimulation. PDC stimulated the T cells to produce γ‐interferon (IFN‐γ) and interleukin‐(IL)‐10, whereas CD11c+ DC induced lower levels of IFN‐γ, virtually no IL‐10, but significant levels of IL‐5. Analysis of intracellular cytokine production showed simultaneous production of IL‐10 and IFN‐γ in mumps‐specific T cells activated by PDC, a cytokine pattern similar to that described for Th1‐like regulatory cells. Introduction of CpG oligodeoxynucleotides in PDC/T‐cell co‐cultures had synergistic effect on virus‐dependent IFN‐γ production, whereas the other cytokines remained unchanged. Together, our results show that the type of DC involved in reactivation of previously primed T cells may have significant impact on the resulting cytokine response and suggest that targeting of viral antigens and adjuvant to specific DC subsets should be considered in the design of therapeutic antiviral vaccines.
Immunomodulation of Japanese Encephalitis Vaccine Through CpG Oligodeoxynucleotides in Mice
Authors: Sidhapuriwala J. N. , Sivalingam S. P. , Lu J. , Moochhala S. M. 
Published: August 2006

AbstractSynthetic oligodeoxynucleotides (ODN) containing unmethylated cytosine guanine (CpG) dinucleotides motifs act as immune adjuvant and provide means of modulation to immune responses when co‐delivered with antigens. They stimulate both innate and adaptive immune responses and induce T helper 1 (Th1) immune responses. We investigated the immunomodulation of Japanese encephalitis (JE) vaccine using CpG ODN as an adjuvant. Mice were immunized with one dose of JE vaccine 0.1 ml with different concentrations (10, 25 and 100 μg) of CpG ODN. The serum antibody level and cytokines were evaluated and compared with mice immunized with two doses of JE vaccine alone. Our studies revealed that anti‐JE antibody level in mice immunized with single dose of 0.1 ml JE vaccine and 100 μg CpG ODN were almost equal to mice immunized with two doses of JE vaccine alone. Furthermore, CpG ODN enhanced the production of TNF‐α and Th1‐mediated cytokines, including IFN‐γ and IL‐2 compared with JE vaccine alone. In addition, absence of any significant changes in biochemical, haematological and histological studies suggest that CpG ODN are safe adjuvants for JE vaccine. Therefore, it is inferred that CpG ODN are effective and improve the efficacy of JE vaccine.
Increased Soluble 4‐1BB Ligand (4‐1BBL) Levels in Peripheral Blood of Patients with Multiple Sclerosis
Authors: Liu G.‐z. , Gomes A. C. , Putheti P. , Karrenbauer V. , Kostulas K. , Press R. , Hillert J. , Hjelmström P. , Gao X.‐G. 
Published: August 2006

Abstract4‐1BB ligand (4‐1BBL; CD137L) is a member of the tumour necrosis factor superfamily expressed primarily on antigen presenting cells such as B cells, macrophages and dendritic cells. Its engagement with the receptor 4‐1BB (CD137) has been shown to promote T‐cell activation and regulate proliferation and survival of T cells. The role of the costimulatory molecule in multiple sclerosis (MS) remains unclear. In this study, the expression of 4‐1BBL and soluble 4‐1BBL (s4‐1BBL) protein levels were analysed in peripheral blood of MS patients. Compared with healthy controls, MS patients had an increase in both plasma s4‐1BBL protein levels and expression of 4‐1BBL in CD14+ monocytes. In contrast, myelin basic protein‐reactive T‐cell proliferation was not found to be inhibited by the use of an anti‐4‐1BBL antibody. The elevated s4‐1BBL protein levels in the MS patients may function as a self‐regulatory mechanism of 4‐1BB/4‐1BBL interaction and costimulation.
Increase in Adhesion Molecules in Cerebrospinal Fluid of Children with Mumps and Mumps Meningitis
Authors: Sulik A. , Wojtkowska M. , Rozkiewicz D. , Oldak E. 
Published: August 2006

AbstractAdhesion molecules play a key role in leucocyte migration into the central nervous system (CNS). Concentrations of endothelial‐derived soluble intercellular adhesion molecule‐1 (sICAM‐1) and leucocyte‐originated soluble L‐selectin (sL‐selectin) in cerebrospinal fluid (CSF) of children with mumps meningitis (mononuclear pleocytosis, n = 33) and mumps (absence of pleocytosis, n = 9) were compared with values from age‐matched control group (n = 19). In 14 patients from the meningitis group, adhesion molecule levels together with albumin concentration were estimated in paired CSF/serum samples to calculate concentration quotients and determine molecule intrathecal release. Both sICAM‐1 (median 3.44 versus 0.86 ng/ml; P < 0.0001) and sL‐selectin (median 29.91 versus 8.52 ng/ml; P < 0.0001) concentrations in CSF were increased in mumps meningitis patients compared with controls. Increased levels of the selected adhesion molecules were also observed in mumps patients without CNS involvement when compared with controls (median sICAM‐1: 1.14 versus 0.86 ng/ml, sL‐selectin: 13.54 versus 8.52 ng/ml; P < 0.01). Additionally, the concentration of adhesion molecules was found to correlate with CSF leucocyte count. Considerable correlation of sICAM‐1 and sL‐selectin quotients and corresponding albumin quotients suggests that a majority of the soluble adhesion molecules originated from the bloodstream. Analysis of adhesion molecule levels demonstrated indirect evidence of brain‐derived fractions. Our results suggest the involvement of adhesion molecules during the early phase of mumps meningitis.
Resistance Against Natural Killer Cell Cytotoxicity: Analysis of Mechanisms
Authors: Hasenkamp J. , Borgerding A. , Wulf G. , Uhrberg M. , Jung W. , Dingeldein S. , Truemper L. , Glass B. 
Published: August 2006

AbstractTarget cell resistance against natural killer (NK) cell‐mediated cytotoxicity obstructs NK cell‐based immunotherapy of leukaemia. Several mechanisms of resistance have been described. Because of lack of simple assays for analysing these mechanisms, their relative impact on a given effector–target pair is mostly unknown. We here analysed the combination of the Granzyme B (GrB) enzyme‐linked immunospot assay (ELISPOT) for the assessment of NK cell reactivity and cytotoxicity assays to estimate target cell escape mechanisms. Target cell recognition failure leads to negative GrB ELISPOT results, whereas target cell resistance shows positive GrB ELISPOT results in the absence of cytotoxicity. We confronted NK cells with the sensitive target cell line K562, and with the resistant cell lines ML2, SupB15 and Raji. ML2 cells sufficiently activated GrB‐release whilst being resistant against cytotoxic granules of NK cells. Partial resistance of Raji results from the interaction of HLA class I with inhibitory killer immunglobulin‐like receptors (KIR) on the NK cells. Failure of target recognition by HLA class I–KIR interaction, lacking ligands to stimulatory NK cell receptors and partial resistance to cytotoxic granules all contributed to resistance of SupB15. In conclusion, revealing the mechanisms of resistance against NK cell‐mediated cytotoxicity may allow improving the results of NK‐based immunotherapy.
Discrepancy in CD3‐Transmembrane Peptide Activity between In Vitro and In Vivo T‐Cell Inhibition
Authors: Collier S. , Bolte A. , Manolios N. 
Published: August 2006

AbstractElectrostatic amino acid interactions between receptor subunits within the T‐cell antigen receptor (TCR) transmembrane domain are critical for the formation of the TCR‐CD3 complex. Core peptide, a short peptide corresponding to the TCR‐α transmembrane region, containing two positively charged amino acids, is known to inhibit T‐cell function in vitro and in vivo. The aim of this study was to examine peptides corresponding to the syntactic transmembrane CD3 region binding to TCR‐α for their ability to inhibit T‐cell activation in vitro and in vivo. Three peptides matching the transmembrane sequence of CD3‐δ, ‐ɛ and ‐γ were synthesized and tested in different biological in vitro and in vivo systems for their effect on T‐cell activity. The CD3‐peptides had no impact on T‐cell function in vitro, but surprisingly, decreased signs of inflammation in the adjuvant arthritis rat model in vivo. Preliminary evidence suggests that peptides with CD3 transmembrane‐derived sequences can inhibit an immune response as assessed by adjuvant‐induced arthritis. The lack of in vitro activity may lead to a wasteful disregard of active compounds in the process of drug discovery and development.
Cutis laxa acquisita associated with cutaneous mastocytosis
Authors: Mahajan Vikram K. , Sharma Nand Lal , Garg Geeta 
Published: August 2006

A female child, a product of a nonconsanguineous parentage and normal pregnancy, was seen first at the age of 4 years. She had suffered from recurrent episodes of multiple, erythematous, confluent plaques and a few bullous lesions all over the body since infancy. The child was irritable but had no history of flushing, dyspnea, wheezing, or frequent diarrhea. Darier's sign was strongly positive and systemic examination did not reveal any abnormality. Routine laboratory investigations were normal and a skin biopsy specimen revealed an unremarkable epidermis and dense proliferation of round to spindle‐shaped mast cells which stained positive for metachromatic granules (Fig. 1). With the diagnosis of urticaria pigmentosa, she was managed with antihistaminic drugs and the parents were advised to handle the child gently. She did not report for further follow‐up.Photomicrograph of skin histology showing metachromatic granules (toluidine blue, ×40)imageRecently, the child, now 8 years of age, was brought again with finely wrinkled, lax, and redundant skin, especially of the face, giving her a senile appearance (Fig. 2). Systemic examination did not show any abnormality. History revealed that the child had been asymptomatic during the last 4 years even without treatment, but developed slowly progressive lax and pendulous skin. A repeat biopsy from the lax facial skin revealed sparse and fragmented elastic fibres, normal collagen, and a perivascular and intradermal cellular infiltrate composed of metachromatic mast cells. Her serum α1‐antitrypsin levels were 190.0 mg/dL (normal, 93–224 mg/dL) and a pulmonary function test showed no abnormality. Treatment with antihistaminic drugs was started again and she was advised to have a cosmetic facial uplift at a later stage.Patient with urticaria pigmentosa seen at 8 years of age showing cutis laxa and a senile appearanceimage
Head louse infestations: the “no nit” policy and its consequences
Authors: Mumcuoglu Kosta Y. , Meinking Terri A. , Burkhart Craig N. , Burkhart Craig G. 
Published: August 2006

AbstractHealth authorities in the USA, Canada and Australia recommend a “no nit” policy, i.e. the immediate dismissal of all children who have head lice, eggs and/or nits on their hair from school, camp or child‐care settings. These children would be readmitted to the institution only when all head lice, eggs and nits have been removed. The “no nit” policy assumes that all nits seen when examining the scalp are viable and therefore the infested individual should be treated for lice, and all nits must be removed from the scalp. However, it has been repeatedly shown that only a small number of children who have nits on their scalp are also infested with living lice. Accordingly, in the USA alone 4–8 million children are treated unnecessarily for head lice annually, which amounts to 64% of all lice treatments. In addition, 12–24 million school days are lost annually. The annual economic loss owing to missed workdays by parents who have to stay home with their children adds US$4–8 billion to the country's economy. The policy also results in serious psychological problems for children and their parents. Therefore, the “no nit” policy should be abandoned and alternative ways of examination and treatment for head lice should be found.