bluuebunny/crossref_metadata_2025_split huggingface dataset:
Responses to fish predation and nutrients by plankton at different levels of taxonomic resolution
Authors: Hansson Lars‐Anders , Gyllström Mikael , Ståhl‐Delbanco Annika , Svensson Marie 
Published: November 2004

Summary1. To improve mechanistic understanding of plankton responses to eutrophication, a mesocosm experiment was performed in the shallow littoral zone of a south Swedish lake, in which nutrient and fish gradients were crossed in a fully factorial design.2. Food chain theory accurately predicted total biomass development of both phyto‐ and zooplankton. However, separating zooplankton and algae into finer taxonomic groups revealed a variety of responses to both nutrient and fish gradients.3. That both nutrients and fish are important for phytoplankton dynamics was seen more clearly when viewing each algal group separately, than drawing conclusions only from broad system variables such as chlorophyll a concentration or total phytoplankton biovolume.4. In some taxa, physiological constraints (e.g. sensitivity to high pH and low concentrations of free CO2) and differences in competitive ability may be more important for the biomass development than fish predation, grazing by herbivorous zooplankton, and nutrient availability.5. We conclude that food chain theory accurately predicted responses in system variables, such as total zooplankton or algal biomass, which are shaped by the dynamics of certain strong interactors (‘keystone species’), such as large cladocerans, cyanobacteria and edible algae (<50 μm), whereas responses at finer taxonomic levels cannot be predicted from current theory.
Effects of fish and nutrient additions on food‐web stability in a charophyte‐dominated lake
Authors: Van De Bund Wouter J. , Van Donk Ellen 
Published: November 2004

Summary1. The response of major food‐web constituents to combinations of nutrient addition and zooplanktivorous fish abundance was tested during two subsequent years in the shallow charophyte‐dominated lake Naardermeer in the Netherlands, using in situ enclosures.2. Treatment effects differed sharply between study years. In 1998, when the summer temperature was low (17–21 °C), high algal biomass only developed at high nutrient levels in the presence of fish, but with no major effect on Chara biomass. In 1999, when the summer temperature was relatively high (20–25 °C), algal blooms occurred at high nutrient levels regardless of fish abundance, and were associated with a drastic decline in Chara biomass.3. Differences between years in temperature and initial zooplankton composition and biomass were likely to contribute to the varying relative importance of top‐down and bottom‐up effects in these enclosure experiments.4. The results suggest that when nutrient loads are increased towards levels where the macrophyte‐dominated state is being destabilised, a ‘switch’ is more likely to occur in warm summers.
Continental‐scale patterns of nutrient and fish effects on shallow lakes: introduction to a pan‐European mesocosm experiment
Authors: Stephen D. , Balayla D. M. , Bécares E. , Collings S. E. , Fernández‐Aláez C. , Fernández‐Aláez M. , Ferriol C. , García P. , Gomá J. , Gyllström M. , Hansson L.‐A. , Hietala J. , Kairesalo T. , Miracle M. R. , Romo S. , Rueda J. , Ståhl‐Delbanco A. , Svensson M. , Vakkilainen K. , Valentín M. , Van de Bund W. J. , Van Donk E. , Vicente E. , Villena M. J. , Moss B. 
Published: November 2004

Summary1. Shallow lake ecosystems are normally dominated by submerged and emergent plants. Biological stabilising mechanisms help preserve this dominance. The systems may switch to dominance by phytoplankton, however, with loss of submerged plants. This process usually takes place against a background of increasing nutrient loadings but also requires additional switch mechanisms, which damage the plants or interfere with their stabilising mechanisms.2. The extent to which the details or even major features of this general model may change with geographical location are not clear. Manipulation of the fish community (biomanipulation) has often been used to clear the water of algae and restore the aquatic plants in northerly locations, but it is again not clear whether this is equally appropriate at lower latitudes.3. Eleven parallel experiments (collectively the International Mesocosm Experiment, IME) were carried out in six lakes in Finland, Sweden, England, the Netherlands and Spain in 1998 and 1999 to investigate the between‐year and large‐scale spatial variation in relationships between nutrient loading and zooplanktivorous fish on submerged plant and plankton communities in shallow lakes.4. Comparability of experiments in different locations was achieved to a high degree. Cross‐laboratory comparisons of chemical analyses revealed some systematic differences between laboratories. These are unlikely to lead to major misinterpretations.5. Nutrient addition, overall, had its greatest effect on water chemistry then substantial effects on phytoplankton and zooplankton. Fish addition had its major effect on zooplankton and did not systematically change the water chemistry. There was no trend in the relative importance of fish effects with latitude, but nutrient addition affected more variables with decreasing latitude.6. The relative importance of top‐down and bottom‐up influences on the plankton differed in different locations and between years at the same location. The outcome of the experiments in different years was more predictable with decreasing latitude and this was attributed to more variable weather at higher latitudes that created more variable starting conditions for the experiments.
Continental‐scale patterns of nutrient and fish effects on shallow lakes: synthesis of a pan‐European mesocosm experiment
Authors: Moss B. , Stephen D. , Balayla D. M. , Bécares E. , Collings S. E. , Fernández‐Aláez C. , Fernández‐Aláez M. , Ferriol C. , García P. , Gomá J. , Gyllström M. , Hansson L.‐A. , Hietala J. , Kairesalo T. , Miracle M. R. , Romo S. , Rueda J. , Russell V. , Ståhl‐Delbanco A. , Svensson M. , Vakkilainen K. , Valentín M. , Van de Bund W.J. , Van Donk E. , Vicente E. , Villena M.J. 
Published: November 2004

Summary1. Results are analysed from 11 experiments in which effects of fish addition and nutrient loading on shallow lakes were studied in mesocosms. The experiments, five in 1998, six in 1999, were carried out in six lakes, distributed from Finland to southern Spain, according to a standard protocol.2. Effects of the treatments on 29 standard chemical, phytoplankton and zooplankton variables are examined to assess the relative importance of bottom‐up (nutrient enrichment) and top‐down (fish predation) effects. For each year, the experiments in different locations are treated as replicates in a meta‐analysis. Results of individual experiments are then compared in terms of the patterns of significant influences of nutrient addition and fish predation with these overall results (the baseline), and between years in the same location.3. The overall meta‐analysis gave consistent results across the 2 years, with nutrient loading influencing all of the chemical variables, and on average 31% of primary producer and 39% of zooplankton variables. In contrast, fish influenced none of the chemical variables, 11% of the primary producer and 44% of the zooplankton variables. Nutrient effects on the system were thus about three times greater than fish effects, although fish effects were not inconsiderable.4. The relative importance of nutrients and fish in individual experiments often differed between years at the same location and effects deviated to varying degrees from the baseline. These deviations were treated as measures of consistency (predictability) of conclusions in repeat experiments. Consistency increased southwards and this is interpreted as a consequence of more variable annual weather northwards.5. The influence of nutrient loading was greater southwards and this was probably manifested through naturally greater annual macrophyte abundance in warmer locations in consequence of the longer plant growing‐season. There was no trend in the relative importance of fish effects with latitude but this may partly be an artefact of the simple fish community used. These findings suggest that nutrient control should be a greater priority than biomanipulation in the restoration of eutrophicated shallow lakes in warm temperate regions.6. Starting conditions affected the outcome of experiments. High initial concentrations of total phosphorus and planktonic chlorophyll a concentration (created by local conditions prior to the experiment) led to de‐emphasis of the importance of nutrient loading in the experiment.
Late‐ and Post‐Glacial history of the Mustelidae in Europe
Authors: SOMMER ROBERT , BENECKE NORBERT 
Published: November 2004

ABSTRACT 1. Analyses of the subfossil records of mustelid species in Europe indicate specific differences in the pattern of temporal and spatial recolonization of central Europe after the maximum glaciation of the last glacial period. 2. For Meles meles, Martes martes and (with some reservations) Mustela putorius it can be seen that the populations were separated in several glacial refugia during the maximum glaciation of the Weichselian. In contrast, the European population of Lutra lutra was restricted to a single glacial refuge, which had not been clearly localized until now. 3. Besides the known glacial refugia of the Iberian Peninsula, Italian Peninsula and the Balkans, there is evidence of possible additional glacial refugia for mustelids near the Carpathians, in western Moldova and in the northern Pontic region. 4. Gulo gulo, Mustela nivalis, and Mustela erminea show adaptations for survival in Pleistocene conditions, but they were historically also distributed in the warmer areas of southern Europe. 5. Among the more thermophilic mustelid species, Mustela putorius is likely to have been the earliest immigrant following the maximum glaciation. Meles meles has been recorded in comparably early times and also seems to be relatively tolerant of climatic extremes. It is clear that Martes martes had already arrived in central Europe during the Allerød, in connection with the recolonization by birch and pine woods. Lutra lutra, by contrast, seems to have been an absolute Holocene immigrant.
Coat colour variation in the banded palm civet Hemigalus derbyanus and in Owston's civet Chrotogale owstoni
Authors: VERON GÉRALDINE , LAIDLAW RUTH , ROSENTHAL SHELAGH HEARD , STREICHER ULRIKE , ROBERTON SCOTT 
Published: November 2004

ABSTRACT 1. Coat colour variation was studied in two viverrid species belonging to the subfamily Hemigalinae, on the basis of museum specimens and observations of live animals. 2. In both species, polymorphism and ontogenetic colour change occur, and in the Owston's civet, sexual dimorphism in coat colour was identified.
Levamisole can reduce bait monopolization in wild red foxes Vulpes vulpes
Authors: GENTLE MATT , MASSEI GIOVANNA , SAUNDERS GLEN 
Published: November 2004

ABSTRACT 1. Baits are used worldwide to deliver vaccines, contraceptives and poison to wild animal species. In carnivores, multiple bait uptake and bait monopolization by dominant individuals may reduce baiting effectiveness. This study investigated whether a conditioned‐taste‐aversion agent, levamisole, can be used to decrease bait consumption by individual wild foxes Vulpes vulpes. 2. The results indicated that after consuming levamisole‐treated baits, foxes avoided eating treated baits but consumed untreated baits. We concluded that the reduction in bait consumption was achieved through learned aversion to levamisole rather than via conditioned‐taste‐aversion to baits. Adding levamisole to baits could potentially be used to reduce bait monopolization by individual wild foxes.
The Free Economy and the Schizophrenic State: Ideology and the Conservatives
Authors: GARNETT MARK 
Published: November 2004

This article focuses on Michael Howard's ideas to illustrate ideological developments within the Conservative party. It recognises that the ideas of a democratic organisation cannot be represented by the thoughts of a single individual, but Howard provides useful insights. He won the leadership unopposed in November 2003 partly because he seemed likely to perform well in debates with Tony Blair, but also because he offered the prospect of policy reform on a range of issues without a radical departure from the Thatcher legacy.Soon after becoming leader Howard issued an unusually detailed statement of his beliefs. This showed him to be a convinced economic liberal, whose thinking has been heavily influenced by America. The main departure from Thatcherism is that he is even more antipathetic towards the state. This is difficult to reconcile with his support for UK 'sovereignty' within the EU, his hard line on law and order issues, and his insistence that there are no plans to privatise the NHS. It is unlikely to provide a platform for a significant Tory recovery.
Bank and Nonbank Financial Intermediation
Authors: BOND PHILIP 
Published: November 2004

ABSTRACTConglomerates, trade credit arrangements, and banks are all instances of financial intermediation. However, these institutions differ significantly in the extent to which the projects financed absorb aggregate intermediary risk, in whether or not intermediation is carried out by a financial specialist, in the type of projects they fund and in the type of claims they issue to investors. The paper develops a simple unified model that both accounts for the continued coexistence of these different forms of intermediation, and explains why they differ. Specific applications to conglomerate firms, trade credit, and banking are discussed.
The Effect of Banking Relationships on the Firm's IPO Underpricing
Authors: SCHENONE CAROLA 
Published: November 2004

ABSTRACTThis paper investigates the effects of pre‐IPO banking relationships on a firm's IPO. Using a new and unique data set, which compares the firm's pre‐IPO banking relationships to the underwriters managing the firm's new issue, I test whether banking relationships established before the firm's IPO ameliorate asymmetric informa tion problems behind high IPO underpricing. The results show that firms with a pre‐IPO banking relationship with a prospective underwriter face about 17% lower underpricing than firms without such banking relationships. These results are robust to controlling for the firm's endogenous selection of the pre‐IPO banking institution.
NK Cells Contribute to the Control ofTrypanosoma cruziInfection by Killing Free Parasites by Perforin-Independent Mechanisms
Authors: Lieke Thorsten , Graefe Sebastian E. B. , Klauenberg Ulricke , Fleischer Bernhard , Jacobs Thomas 
Published: November 2004

ABSTRACTThe protozoan parasiteTrypanosoma cruzicirculates in the blood as trypomastigotes and invades a variety of cells to multiply intracellularly as amastigotes. The acute phase leads to an immune response that restricts the proliferation of the parasite. However, parasites are able to persist in different tissues, which causes the pathology of Chagas' disease. Natural killer (NK) cells play an important role in innate resistance to a variety of pathogens. In the present study we analyzed whether NK cells participated in the control of experimentalT. cruziinfection. NK cells were depleted from C57BL/6 mice by antiasialo antibodies. This treatment caused an increased parasitemia during the acute phase, but tissue parasite burdens were not significantly altered according to quantitative real-time PCR. Our results demonstrated that NK cells were activated during the initial phase of aT. cruziinfection and exhibited a contact-dependent antiparasitic activity against extracellular parasites that was independent from perforin. Thus, NK cells limit the propagation of the parasite by acting on circulatingT. cruzitrypomastigotes.
Resistance ofMycoplasma pulmonisto Complement Lysis Is Dependent on the Number of Vsa Tandem Repeats: Shield Hypothesis
Authors: Simmons Warren L. , Denison Amy M. , Dybvig Kevin 
Published: November 2004

ABSTRACTThe Vsa proteins are associated with the virulence of the murine respiratory pathogenMycoplasma pulmonis. The antigens consist of a conserved N-terminal region that is combined with one of several different variable C-terminal regions comprised of tandem repeats.M. pulmonisstrains that produce VsaA with about 40 tandem repeats do not adhere to polystyrene or erythrocytes and are highly resistant to complement killing. Strains that produce VsaA with three tandem repeats adhere strongly to polystyrene and erythrocytes and are highly susceptible to complement killing. We report here that the resistance to complement lysis was not due to a lack of activation of the complement cascade. Isolation and analysis ofM. pulmonisstrains that produced Vsa proteins other than VsaA (VsaG and VsaI) with either long or short repeat regions indicated that adherence to polystyrene and resistance to complement were dependent on the length of the repeat region but not on the Vsa type. Furthermore,M. pulmonisVsa variants were susceptible to the polypeptide pore-forming molecule gramicidin D, independent of the Vsa type and length. Collectively, the data indicate the Vsa proteins nonspecifically mediateM. pulmonissurface interactions and function to sterically hinder access of complement to the mycoplasma cell membrane while permitting access of smaller molecules.
Salmonella entericaSerovar Typhimurium Infection Induces Cyclooxygenase 2 Expression in Macrophages: Involvement ofSalmonellaPathogenicity Island 2
Authors: Uchiya Kei-ichi , Nikai Toshiaki 
Published: November 2004

ABSTRACTSalmonellapathogenicity island 2 (SPI-2) is required for intramacrophage survival and systemic infection in mice. We have recently reported thatSalmonella entericacauses activation of the protein kinase A (PKA) signaling pathway in a manner dependent on SPI-2, resulting in the upregulation of interleukin-10 expression in macrophages (K. Uchiya et al., Infect. Immun. 72:1964-1973, 2004). We show in the present study the involvement of SPI-2 in a signal transduction pathway that induces the expression of cyclooxygenase 2 (COX-2), an inducible enzyme involved in the synthesis of prostanoids. High levels of prostaglandin E2(PGE2) and prostacyclin (PGI2), which are known to activate the PKA signaling pathway via their receptors, were induced in J774 macrophages infected with wild-typeSalmonellacompared to a strain carrying a mutation in thespiCgene, located within SPI-2. The increased production of both prostanoids was dependent on COX-2. COX-2 expression was dose dependently blocked by treatment with a specific inhibitor of the extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway, and the phosphorylation level of ERK1/2 was higher in macrophages infected with wild-typeSalmonellacompared to thespiCmutant. Taken together, these results indicate thatSalmonellacauses an SPI-2-dependent ERK1/2 activation that leads to increased COX-2 expression, resulting in the upregulation of PGE2and PGI2production in macrophages. A COX-2 inhibitor inhibited not onlySalmonella-induced activation of the PKA signaling pathway but also growth of wild-typeSalmonellawithin macrophages, suggesting thatSalmonellautilizes the COX-2 pathway to survive within macrophages and that the mechanism involves activation of the PKA signaling pathway.
Bystander Activation of CD8+T Lymphocytes during Experimental Mycobacterial Infection
Authors: Gilbertson Brad , Germano Susie , Steele Pauline , Turner Steven , de St. Groth Barbara Fazekas , Cheers Christina 
Published: November 2004

ABSTRACTInfection of C57BL/6 mice withMycobacterium aviumleads to the activation of both CD4+and CD8+gamma interferon (IFN-γ)-producing T cells, although the CD8+cells play no role in protection against infection. Using transfer of different lines of transgenic T cells with T-cell receptors (TCRs) which recognize irrelevant antigens, we show here that transferred CD8+T cells from two of the three lines were activated to the same degree as the host cells, suggesting that the majority of the IFN-γ-producing CD8+T cells of the host represented bystander activation. The third line, specific for the male HY antigen, showed no activation. Activation required the participation of the CD28 coreceptor on T cells and was unaffected by the removal of CD44hi(memory phenotype) T cells. The transferred CD8+T cells proliferated in vivo, although this was not essential for IFN-γ production. Taken together, these data are highly reminiscent of homeostatic proliferation of TCR transgenic T cells upon transfer to lymphopenic hosts, and suggest low-affinity stimulation through the TCR, possibly by self peptides. The findings are discussed in relation to homeostatic proliferation and their significance in the possible induction of autoimmune disease.
Redirecting the Humoral Immune Response againstStreptococcus mutansAntigen P1 with Monoclonal Antibodies
Authors: Oli Monika W. , Rhodin Nikki , McArthur William P. , Brady L. Jeannine 
Published: November 2004

ABSTRACTThe adhesin P1 ofStreptococcus mutanshas been studied as an anticaries vaccine antigen. An anti-P1 monoclonal antibody (MAb) bound toS. mutansprior to mucosal immunization of mice was shown previously to alter the amount, specificity, isotype, and biological activity of anti-P1 antibodies. The present study was undertaken to screen this and four additional anti-P1 MAbs for immunomodulatory activity when complexed withS. mutansand administered by a systemic route and to evaluate sera from immunized mice for the ability to inhibit adherence ofS. mutansto immobilized human salivary agglutinin. All five MAbs tested influenced murine anti-P1 serum antibody responses in terms of subclass distribution and/or specificity. The effects varied depending on which MAb was used and its coating concentration. Two MAbs promoted a more effective, and two others a less effective, adherence inhibition response. An inverse relationship was observed between the ability of the MAbs themselves to inhibit adherence and the ability of antibodies elicited following immunization with immune complexes to inhibit adherence. Statistically significant correlations were demonstrated between the levels of anti-P1 serum immunoglobulin G2a (IgG2a) and IgG2b, but not of IgG1 or IgG3, and the ability of sera from immunized animals to inhibit bacterial adherence. These results indicate that multiple anti-P1 MAbs can mediate changes in the immune response and that certain alterations are potentially more biologically relevant than others. Immunomodulation by anti-P1 MAbs represents a useful strategy to improve the beneficial immune response againstS. mutans.