Garden and Landscape-Scale Correlates of Moths of Differing Conservation Status: Significant Effects of Urbanization and Habitat Diversity

Moths are abundant and ubiquitous in vegetated terrestrial environments and are pollinators, important herbivores of wild plants, and food for birds, bats and rodents. In recent years, many once abundant and widespread species have shown sharp declines that have been cited by some as indicative of a widespread insect biodiversity crisis. Likely causes of these declines include agricultural intensification, light pollution, climate change, and urbanization; however, the real underlying cause(s) is still open to conjecture. We used data collected from the citizen science Garden Moth Scheme (GMS) to explore the spatial association between the abundance of 195 widespread British species of moth, and garden habitat and landscape features, to see if spatial habitat and landscape associations varied for species of differing conservation status. We found that associations with habitat and landscape composition were species-specific, but that there were consistent trends in species richness and total moth abundance. Gardens with more diverse and extensive microhabitats were associated with higher species richness and moth abundance; gardens near to the coast were associated with higher richness and moth abundance; and gardens in more urbanized locations were associated with lower species richness and moth abundance. The same trends were also found for species classified as increasing, declining and vulnerable under IUCN (World Conservation Union) criteria. However, vulnerable species were more strongly negatively affected by urbanization than increasing species. Two hypotheses are proposed to explain this observation: (1) that the underlying factors causing declines in vulnerable species (e.g., possibilities include fragmentation, habitat deterioration, agrochemical pollution) across Britain are the same in urban areas, but that these deleterious effects are more intense in urban areas; and/or (2) that urban areas can act as ecological traps for some vulnerable species of moth, the light drawing them in from the surrounding landscape into sub-optimal urban habitats.     

Copper transport during lactation in transgenic mice expressing the human ATP7A protein

We investigated the membrane trafficking of AQP3 induced by epinephrine in Caco-2 cells to clarify the digestive absorption of glycerol permeated by AQP3. Epinephrine was found to promote within 60 min the translocation of AQP3 from the cytoplasmic fraction to the plasma membrane. This increased trafficking of AQP3 was suppressed by phospholipase C and protein kinase C (PKC) inhibitors and a phorbol ester accelerated the trafficking of AQP3 to the membrane fraction. In contrast, adenylyl cyclase (AC) and protein kinase A (PKA) inhibitors did not have any effect on the increased in trafficking of AQP3 by epinephrine and an AC activator did not affect the trafficking of AQP3. Phosphorylation of a threonine (514) residue in PKC was detected upon the treatment with epinephrine and the temporal transitional pattern of this phosphorylation paralleled that of the increased trafficking of AQP3. These results suggest that PKC modulates the trafficking of AQP3.     

Bioinformatic and Expression Analyses of Genes Mediating Zinc Homeostasis in Nostoc punctiforme

Zinc homeostasis was investigated in Nostoc punctiforme. Cell tolerance to Zn²⁺ over 14 days showed that ZnCl₂ levels above 22 μM significantly reduced cell viability. After 3 days in 22 μM ZnCl₂, ca. 12% of the Zn²⁺ was in an EDTA-resistant component, suggesting an intracellular localization. Zinquin fluorescence was detected within cells exposed to concentrations up to 37 μM relative to 0 μM treatment. Radiolabeled ⁶⁵Zn showed Zn²⁺ uptake increased over a 3-day period, while efflux occurred more rapidly within a 3-h time period. Four putative genes involved in Zn²⁺ uptake and efflux in N. punctiforme were identified: (i) the predicted Co/Zn/Cd cation transporter, putative CDF; (ii) the predicted divalent heavy-metal cation transporter, putative Zip; (iii) the ATPase component and Fe/Zn uptake regulation protein, putative Fur; and (iv) an ABC-type Mn/Zn transport system, putative zinc ZnuC, ZnuABC system component. Quantitative real-time PCR indicated the responsiveness of all four genes to 22 μM ZnCl₂ within 3 h, followed by a reduction to below basal levels after 24 h by putative ZIP, ZnuC, and Fur and a reduction to below basal level after 72 h by putative CDF efflux gene. These results demonstrate differential regulation of zinc transporters over time, indicating a role for them in zinc homeostasis in N. punctiforme.     

Closed-loop seizure control with very high frequency electrical stimulation at seizure onset in the GAERS model of absence epilepsy

A closed-loop system for the automated detection and control of epileptic seizures was created and tested in three Genetic Absence Epilepsy Rats from Strasbourg (GAERS) rats. In this preliminary study, a set of four EEG features were used to detect seizures and three different electrical stimulation strategies (standard (130 Hz), very high (500 Hz) and ultra high (1000 Hz)) were delivered to terminate seizures. Seizure durations were significantly shorter with all three stimulation strategies when compared to non-stimulated (control) seizures. We used mean seizure duration of epileptiform discharges persisting beyond the end of electrical stimulation as a measure of stimulus efficacy. When compared to the duration of seizures stimulated in the standard approach (7.0 s ± 10.1), both very high and ultra high frequency stimulation strategies were more effective at shortening seizure durations (1.3 ± 2.2 s and 3.5 ± 6.4 s respectively). Further studies are warranted to further understand the mechanisms by which this therapeutic effect may be conveyed, and which of the novel aspects of the very high and ultra high frequency stimulation strategies may have contributed to the improvement in seizure abatement performance when compared to standard electrical stimulation approaches.     

Stress and microbial endocrinology: prospects for ruminant nutrition

The feed efficiency of ruminant meat and dairy livestock can be significantly influenced by factors within their living environments. In particular, events perceived by the animals as stressful (such as parturition, transport or handling) have been found to affect susceptibility to infection. It has been well documented that even minor stress such as weighing can result in an increase in colonisation and faecal shedding of enteric pathogens such as Salmonella enterica and Escherichia coli O157:H7. Such infections affect both ruminant overall health and therefore performance, and are a particular problem for the meat production industries. Prior explanations for stress enhancing the likelihood of infection is that activation of the sympathetic nervous system under stress leads to the release of neuroendocrine mediators such as the catecholamine stress hormones noradrenaline and adrenaline, which may impair innate and adaptive immunity. More recently, however, another equally compelling explanation, viewed through the lens of the newly recognised microbiological discipline of microbial endocrinology is that the myriad of bacteria within the ruminant digestive tract are as responsive to the hormonal output of stress as the cells of their host. Work from our laboratories has shown that enteric pathogens have evolved systems for directly sensing stress hormones. We have demonstrated that even brief exposure of enteric pathogens to physiological concentrations of stress hormones can result in massive increases in growth and marked changes in expression of virulence factors such as adhesins and toxins. Happy, less stressed ruminants may therefore be better-nourished animals and safer sources of meat. This article reviews evidence that stress, as well as affecting nutrition, in ruminants is correlated with increased risk of enteric bacterial infections, and examines the molecular mechanisms that may be at work in both processes.     

Formation of Transient Non-Protein Calcium Pores by Lysophospholipids in S49Lymphoma cells

Palmitoyl-lysophosphatidylcholine promotes a transient calcium influx in lymphoma cells. Previously, it was observed that this influx was accompanied by a temporary increase in propidium iodide permeability that appeared linked to calcium entry. Those studies demonstrated that cobalt or nickel could block the response to lysophosphatidylcholine and raised the question of whether the calcium conductance involved specific channels. This communication describes a series of experiments to address that issue. The time dependence and structural specificity of the responses to lysophosphatidylcholine reinforced the hypothesis of a specific channel or transporter. Nevertheless, observations using patch clamp or calcium channel blockers suggested that this “channel” does not involve proteins. Alternative protein-mediated mechanisms such as indirect involvement of the sodium-calcium exchanger and the sodium-potassium ATPase were also excluded. Experiments with extracellular and intracellular calcium chelators suggested a common route of entry for calcium and propidium iodide. More directly, the ability of lysophosphatidylcholine to produce cobalt-sensitive permeability to propidium iodide was reproduced in protein-free artificial membranes. Finally, the transient nature of the calcium time course was rationalized quantitatively by the kinetics of lysophosphatidylcholine metabolism. These results suggest that physiological concentrations of lysophosphatidylcholine can directly produce membrane pores that mimic some of the properties of specific protein channels.This revised version was published online in June 2005 with a corrected cover date.     

Resuscitation of Salmonella enterica Serovar Typhimurium and Enterohemorrhagic Escherichia coli from the Viable but Nonculturable State by Heat-Stable Enterobacterial Autoinducer

Salmonella enterica serovar Typhimurium and enterohemorrhagic Escherichia coli were stressed by prolonged incubation in water microcosms until it was no longer possible to observe colony formation when samples were plated on nonselective medium. Overnight incubation of samples in nutrient-rich broth medium supplemented with growth factors, however, allowed resuscitation of stressed and viable but nonculturable cells so that subsequent plating yielded observable colonies for significantly extended periods of time. The growth factors were (i) the trihydroxamate siderophore ferrioxamine E (for Salmonella only), (ii) the commercially available antioxidant Oxyrase, and (iii) the heat-stable autoinducer of growth secreted by enterobacterial species in response to norepinephrine. Analysis of water microcosms with the Bioscreen C apparatus confirmed that these supplements enhanced recovery of cells in stressed populations; enterobacterial autoinducer was the most effective, promoting resuscitation in populations that were so heavily stressed that ferrioxamine E or Oxyrase had no effect. Similar results were observed in Bioscreen analysis of bacterial populations stressed by heating. Patterns of resuscitation of S. enterica serovar Typhimurium rpoS mutants from water microcosms and heat stress were qualitatively similar, suggesting that the general stress response controlled by the σ^s subunit of RNA polymerase plays no role in autoinducer-dependent resuscitation. Enterobacterial autoinducer also resuscitated stressed populations of Citrobacter freundii and Enterobacter agglomerans.     

Size-Energy Relationships in Ecological Communities

Hypotheses that relate body size to energy use are of particular interest in community ecology and macroecology because of their potential to facilitate quantitative predictions about species interactions and to clarify complex ecological patterns. One prominent size-energy hypothesis, the energetic equivalence hypothesis, proposes that energy use from shared, limiting resources by populations or size classes of foragers will be independent of body size. Alternative hypotheses propose that energy use will increase with body size, decrease with body size, or peak at an intermediate body size. Despite extensive study, however, size-energy hypotheses remain controversial, due to a lack of directly-measured data on energy use, a tendency to confound distinct scaling relationships, and insufficient attention to the ecological contexts in which predicted relationships are likely to occur. Our goal, therefore, was to directly evaluate size-energy hypotheses while clarifying how results would differ with alternate methods and assumptions. We comprehensively tested size-energy hypotheses in a vertebrate frugivore guild in a tropical forest in Madagascar. Our test of size-energy hypotheses, which is the first to examine energy intake directly, was consistent with the energetic equivalence hypothesis. This finding corresponds with predictions of metabolic theory and models of energy distribution in ecological communities, which imply that body size does not confer an advantage in competition for energy among populations or size classes of foragers. This result was robust to different assumptions about energy regulation. Our results from direct energy measurement, however, contrasted with those obtained with conventional methods of indirect inference from size-density relationships, suggesting that size-density relationships do not provide an appropriate proxy for size-energy relationships as has commonly been assumed. Our research also provides insights into mechanisms underlying local size-energy relationships and has important implications for predicting species interactions and for understanding the structure and dynamics of ecological communities.     

Catecholamine inotropes as growth factors for Staphylococcus epidermidis and other coagulase-negative staphylococci

Drugs commonly used in intensive care settings were assayed for their ability to affect the growth of Staphylococcus epidermidis in a minimal salts medium containing 30% serum. Of 28 compounds tested, the inotropic catecholamines adrenaline, dobutamine, dopamine, isoprenaline and noradrenaline significantly stimulated bacterial growth. These drugs, but not structurally similar compounds lacking a dihydroxybenzoyl moiety (such as tyramine, phenylephrine and salbutamol), were able to remove iron from iron-saturated transferrin and to supply transferrin-bound 55Fe to S. epidermidis cells. Similar results were observed with a range of coagulase-negative staphylococci associated with line infections, but not with Staphylococcus aureus (including MRSA).