Growing evidence for declines in wild bees calls for the development and implementation of effective mitigation measures. Enhancing floral resources is a widely accepted measure for promoting bees in ...agricultural landscapes, but effectiveness varies considerably between landscapes and regions. We hypothesize that this variation is mainly driven by a combination of the direct effects of measures on local floral resources and the availability of floral resources in the surrounding landscape. To test this, we established wildflower strips in four European countries, using the same seed mixture of forage plants specifically targeted at bees. We used a before–after control–impact approach to analyse the impacts of wildflower strips on bumblebees, solitary bees and Red List species and examined to what extent effects were affected by local and landscape‐wide floral resource availability, land‐use intensity and landscape complexity. Wildflower strips generally enhanced local bee abundance and richness, including Red‐listed species. Effectiveness of the wildflower strips increased with the local contrast in flower richness created by the strips and furthermore depended on the availability of floral resources in the surrounding landscape, with different patterns for solitary bees and bumblebees. Effects on solitary bees appeared to decrease with increasing amount of late‐season alternative floral resources in the landscape, whereas effects on bumblebees increased with increasing early‐season landscape‐wide floral resource availability. Synthesis and applications. Our study shows that the effects of wildflower strips on bees are largely driven by the extent to which local flower richness is increased. The effectiveness of this measure could therefore be enhanced by maximizing the number of bee forage species in seed mixtures, and by management regimes that effectively maintain flower richness in the strips through the years. In addition, for bumblebees specifically, our study highlights the importance of a continuous supply of food resources throughout the season. Measures that enhance early‐season landscape‐wide floral resource availability, such as the cultivation of oilseed rape, can benefit bumblebees by providing the essential resources for colony establishment and growth in spring. Further research is required to determine whether, and under what conditions, wildflower strips result in actual population‐level effects.
Mass‐flowering crops (MFCs) are increasingly cultivated and might influence pollinator communities in MFC fields and nearby semi‐natural habitats (SNHs). Across six European regions and 2 years, we ...assessed how landscape‐scale cover of MFCs affected pollinator densities in 408 MFC fields and adjacent SNHs. In MFC fields, densities of bumblebees, solitary bees, managed honeybees and hoverflies were negatively related to the cover of MFCs in the landscape. In SNHs, densities of bumblebees declined with increasing cover of MFCs but densities of honeybees increased. The densities of all pollinators were generally unrelated to the cover of SNHs in the landscape. Although MFC fields apparently attracted pollinators from SNHs, in landscapes with large areas of MFCs they became diluted. The resulting lower densities might negatively affect yields of pollinator‐dependent crops and the reproductive success of wild plants. An expansion of MFCs needs to be accompanied by pollinator‐supporting practices in agricultural landscapes.
Dopamine and glutamate are key neurotransmitters involved in learning and memory mechanisms of the brain. These two neurotransmitter systems converge on nerve cells in the neostriatum. Dopamine ...modulation of activity-dependent plasticity at glutamatergic corticostriatal synapses has been proposed as a cellular mechanism for learning in the neostriatum. The present research investigated the role of specific subtypes of dopamine receptors in long-term potentiation (LTP) in the corticostriatal pathway, using intracellular recording from striatal neurons in a corticostriatal slice preparation. In agreement with previous reports, LTP could be induced reliably under Mg(2+)-free conditions. This Mg(2+)-free LTP was blocked by dopamine depletion and by the dopamine D-1/D-5 receptor antagonist SCH 23390 but was not blocked by the dopamine D-2 receptor antagonist remoxipride or the GABA(A) antagonist picrotoxin. In dopamine-depleted slices, the ability to induce LTP could be restored by bath application of the dopamine D-1/D-5 receptor agonist, SKF 38393. These results show that activation of dopamine D-1/D-5 receptors by either endogenous dopamine or exogenous dopamine agonists is a requirement for the induction of LTP in the corticostriatal pathway. These findings have significance for current understanding of learning and memory mechanisms of the neostriatum and for theoretical understanding of the mechanism of action of drugs used in the treatment of psychotic illnesses and Parkinson's disease.
The ability to change strategies in different contexts is a form of behavioral flexibility that is crucial for adaptive behavior. The striatum has been shown to contribute to certain forms of ...behavioral flexibility such as reversal learning. Here we report on the contribution of striatal cholinergic interneurons-a key element in the striatal neuronal circuit-to strategy set-shifting in which an attentional shift from one stimulus dimension to another is required. We made lesions of rat cholinergic interneurons in dorsomedial or ventral striatum using a specific immunotoxin and investigated the effects on set-shifting paradigms and on reversal learning. In shifting to a set that required attention to a previously irrelevant cue, lesions of dorsomedial striatum significantly increased the number of perseverative errors. In this condition, the number of never-reinforced errors was significantly decreased in both types of lesions. When shifting to a set that required attention to a novel cue, rats with ventral striatum lesions made more perseverative errors. Neither lesion impaired learning of the initial response strategy nor a subsequent switch to a new strategy when response choice was indicated by a previously relevant cue. Reversal learning was not affected. These results suggest that in set-shifting the striatal cholinergic interneurons play a fundamental role, which is dissociable between dorsomedial and ventral striatum depending on behavioral context. We propose a common mechanism in which cholinergic interneurons inhibit neurons representing the old strategy and enhance plasticity underlying exploration of a new rule.
Recent concern over global pollinator declines has led to considerable research on the effects of pesticides on bees. Although pesticides are typically not encountered at lethal levels in the field, ...there is growing evidence indicating that exposure to field-realistic levels can have sublethal effects on bees, affecting their foraging behaviour, homing ability and reproductive success. Bees are essential for the pollination of a wide variety of crops and the majority of wild flowering plants, but until now research on pesticide effects has been limited to direct effects on bees themselves and not on the pollination services they provide. Here we show the first evidence to our knowledge that pesticide exposure can reduce the pollination services bumblebees deliver to apples, a crop of global economic importance. Bumblebee colonies exposed to a neonicotinoid pesticide provided lower visitation rates to apple trees and collected pollen less often. Most importantly, these pesticide-exposed colonies produced apples containing fewer seeds, demonstrating a reduced delivery of pollination services. Our results also indicate that reduced pollination service delivery is not due to pesticide-induced changes in individual bee behaviour, but most likely due to effects at the colony level. These findings show that pesticide exposure can impair the ability of bees to provide pollination services, with important implications for both the sustained delivery of stable crop yields and the functioning of natural ecosystems.
In the slow channel congenital myasthenic syndrome mutations in genes encoding the muscle acetylcholine receptor give rise to prolonged ion channel activations. The resulting cation overload in the ...postsynaptic region leads to damage of synaptic structures, impaired neuromuscular transmission and fatigable muscle weakness. Previously we identified and characterised in detail the properties of the slow channel syndrome mutation εL221F. Here, using this mutation, we generate a transgenic mouse model for the slow channel syndrome that expresses mutant human ε-subunits harbouring an EGFP tag within the M3–M4 cytoplasmic region, driven by a ~1500bp region of the CHRNB promoter. Fluorescent mutant acetylcholine receptors are assembled, cluster at the motor endplates and give rise to a disease model that mirrors the human condition. Mice demonstrate mild fatigable muscle weakness, prolonged endplate and miniature endplate potentials, and variable degeneration of the postsynaptic membrane. We use our model to investigate ephedrine as a potential treatment. Mice were assessed before and after six weeks on oral ephedrine (serum ephedrine concentration 89±3ng/ml) using an inverted screen test and in vivo electromyography. Treated mice demonstrated modest benefit for screen hang time, and in measures of compound muscle action potentials and mean jitter that did not reach statistical significance. Ephedrine and salbutamol show clear benefit when used in the treatment of DOK7 or COLQ congenital myasthenic syndromes. Our results highlight only a modest potential benefit of these β2-adrenergic receptor agonists for the treatment of the slow channel syndrome.
•We have generated a mouse model of slow channel congenital myasthenic syndrome.•Fluorescent mutant acetylcholine receptors integrate into mouse muscle endplates.•The characteristics of human disease are replicated in the model.•Model shows prolonged endplate current and fatigable weakness.•Oral ephedrine modestly improves neurotransmission and fatigability in model mice.
Highlights • We recorded extracellular single-unit activity from the striatum of two strains of rat during quiet rest. • Putative identified neuronal subtypes included medium spiny neurons (pMSN) and ...fast-spiking interneurons (pFSI). • pFSI in GH rats showed different basal firing properties and were encountered less frequently than in Wistar controls. • AMPH increased Wistar rat pFSI firing rate, but did not significantly change GH rat pFSI activity.
Objectives: In July 2003, the UK Department of Health announced an allocation of £12 million to hospital pharmacists to improve the monitoring and control of anti-infective use over the ensuing 3 ...year period (the Hospital Pharmacy Initiative, or HPI). Chief Pharmacists were asked to use this money for developments to promote prudent antibiotic use and monitoring of antimicrobials within their Trusts. This study aimed to evaluate the impact of the HPI funding, which at the time had been in place for nearly 2 years, on pharmacy activities in this area. Methods: A postal questionnaire was sent to the pharmacy department of each acute hospital Trust in England, aiming to provide a descriptive overview of the activities of hospital pharmacy staff in the field of anti-infectives and to explore the extent to which these activities were made possible by the HPI funding. Results: One hundred and forty-one specialist antimicrobial pharmacy staff were employed in 130 responding Trusts; 89% were pharmacists, 7% pharmacy technicians and the remainder administrative staff. Three-quarters of these staff had been employed due to the funding, resulting in review of antimicrobial prescribing guidelines, antibiotic audit projects and multidisciplinary work with Microbiology/Infectious Diseases staff. Thirteen Trusts gave details of drug acquisition cost savings; over the course of a year, these Trusts saved £1.1 million in total. Conclusions: The HPI funding has facilitated greater interaction between Pharmacy and Microbiology/Infectious Diseases departments than was previously possible. Significant reductions in antibiotic acquisition costs have been demonstrated, though further work is warranted to fully establish the impact of pharmacy activities on clinical and microbiological outcomes.
Background Outpatient and home parenteral antimicrobial therapy (OHPAT) is becoming increasingly commonplace in the UK, enabling those patients who would previously have been obliged to remain in ...hospital for intravenous treatment to be managed as outpatients or in their own homes. The OHPAT service at St Mary's Hospital, London, was established in 2004. This paper describes the types of infection, antimicrobial management and outcomes of patients referred to the service in the 3.5 years since its inception. Patients and methods All inpatients were eligible for OHPAT, provided that they had a serious infection requiring parenteral therapy, were well enough to leave hospital and fulfilled other criteria. We initially used an outpatient clinic model, but as the service developed, treatment was often delivered in patients' homes, with the OHPAT team providing training and assessment of primary care staff. Results Four hundred and sixty-seven patients were referred to the service between September 2004 and April 2008. Of these, 273 received 303 courses of OHPAT, 48 were discharged on oral therapy and 3 patients declined outpatient therapy; the remaining 143 patients were deemed unsuitable for inclusion, most commonly because the patient was too unwell for discharge (28.7%) or their social situation was inappropriate (14.7%). Causative organisms were identified in two-thirds of cases, with methicillin-resistant Staphylococcus aureus implicated in one-third of these. Mean treatment length was 24 days (range 1–165 days), with 7394 inpatient bed-days saved. Less than 5% of patients were readmitted within 28 days with infection- or drug-related problems. There were no cases of Clostridium difficile-associated diarrhoea during or after outpatient treatment, despite extensive use of cephalosporins and other broad-spectrum agents. Patients found the service highly satisfactory and felt that it had improved their quality of life during the treatment period. Conclusions The introduction of the OHPAT service at St Mary's Hospital has proved to be of benefit to patients and hospital efficiency alike.
The analysis of the neural mechanisms responsible for reward-related learning has benefited from recent studies of the effects of dopamine on synaptic plasticity. Dopamine-dependent synaptic ...plasticity may lead to strengthening of selected inputs on the basis of an activity-dependent conjunction of sensory afferent activity, motor output activity, and temporally related firing of dopamine cells. Such plasticity may provide a link between the reward-related firing of dopamine cells and the acquisition of changes in striatal cell activity during learning. This learning mechanism may play a special role in the translation of reward signals into context-dependent response probability or directional bias in movement responses.
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