bluuebunny/crossref_metadata_2025_split huggingface dataset:
Efficacy of a radar‐activated on‐demand system for deterring waterfowl from oil sands tailings ponds
Authors: RONCONI ROBERT A. , CASSADY ST. CLAIR COLLEEN 
Published: December 2005

Summary

Oil sands mining is one of several industrial activities that produces effluent that is dangerous to waterfowl. Such industries require effective systems to deter birds, but current deterrents are not always successful, presumably because wildlife ignore or habituate to them.
We tested a new radar‐activated on‐demand system of deterrence in the oil sands region of Alberta, Canada, by comparing the proportion of birds that landed on a tailings pond while it was activated with the proportion that landed during two other treatments: a continuous, randomly activated, deterrent system, and control periods with no deterrents. We also assessed the efficacy of different stimuli types within the on‐demand system.
Across several bird guilds, only the on‐demand deterrent system significantly reduced the probability of birds landing in comparison with the control treatment. In addition to treatment effects, birds were more likely to land earlier in the spring and when they flew at lower altitudes, and shorebirds were more likely to land than ducks, geese and gulls.
The comparison of stimuli revealed that cannons elicited significantly more response by birds in flight than mechanized peregrine falcon effigies with speakers broadcasting peregrine sounds.
Synthesis and applications. Our results promote the use of on‐demand systems for waterfowl deterrence at tailings ponds and recommend cannons over effigies as stimuli. We suggest that oil sands deterrence efforts should (i) be operational in the early spring, when tailings ponds appear to be most attractive to migrating waterfowl, (ii) target low‐flying waterfowl and shorebirds and (iii) be effective during both day and night. These results and recommendations have potential application for problems of bird deterrence at several other industrial sites.
Statistical methods for analysing responses of wildlife to human disturbance
Authors: PREISLER HAIGANOUSH K. , AGER ALAN A. , WISDOM MICHAEL J. 
Published: December 2005

Summary

Off‐road recreation is increasing rapidly in many areas of the world, and effects on wildlife can be highly detrimental. Consequently, we have developed methods for studying wildlife responses to off‐road recreation with the use of new technologies that allow frequent and accurate monitoring of human–wildlife interactions. To illustrate these methods, we studied the response of Rocky Mountain elk Cervus elaphus L. to all‐terrain vehicles (ATVs), one of the most prominent forms of summer recreation in North America. We studied elk because the species is not only of keen economic and social interest across North America and Europe but also exemplifies species that can be sensitive to human disturbance.
The study was part of a controlled landscape experiment where global positioning system (GPS)‐equipped recreationists traversed an established 32‐km route inside a 1453‐ha elk‐proof enclosure. Elk locations before and during the human disturbances were monitored using an automated telemetry system. The unique data set and study objectives led to our development of statistical methods for analysing the response of wildlife to human disturbance.
We developed a statistical method, referred to as a probabilistic flight response, which accounted for daily circadian rhythms in movement behaviour of elk, and related the probability of flight to distance to the disturbance and a number of environmental covariates. We also present methods for estimating spatially and temporally explicit movement vectors as a way of detecting and visualizing landscape‐level movement patterns.
Using these methods, we observed that elk appeared to respond at relatively long distances (> 1000 m) to ATVs, and that the estimated probability of flight appeared to be higher when elk were closer to the ATV routes, even when the distance to an ATV was large.
Synthesis and applications. Our study quantifies the response of wildlife to human disturbance at a resolution well beyond previous work, and provides methods to improve our understanding of wildlife–human interactions related to management of wildlife and recreation. These methods may be used for any study involving accurate, frequent monitoring of animals and humans with the use of GPS or similar technologies now commonly available.
Invasibility and species richness of island endemic arthropods: a general model of endemic vs. exotic species
Authors: Borges Paulo A. V. , Lobo Jorge M. , de Azevedo Eduardo B. , Gaspar Clara S. , Melo Catarina , Nunes Luis V. 
Published: December 2005

AbstractAim This paper has two objectives. First, we examine how a variety of biotic, abiotic and anthropogenic factors influence the endemic and introduced arthropod richness on an oceanic island. Second, we look at the relationship between the endemic and introduced arthropod richness, to ask whether areas with high levels of endemic species richness deter invasions.Location The work was carried out on a young volcanic island, Terceira, in the Azores.Methods We used standard techniques to collect data on arthropod species richness. Environmental data were obtained from the CIELO climatic model and using GIS. The explanatory value of environmental variables on a small‐scale gradient of endemic and exotic arthropod species richness was examined with generalized linear models (GLMs). In addition, the impact of both endemic and exotic species richness in the communities was assessed by entering them after the environmental variable(s) to see if they contributed significantly to the final model (the hierarchical method).Results Abiotic (climatic and geomorphological) variables gave a better explanation of the variation in endemic species richness, whereas anthropogenic variables explained most of the variation in introduced species richness. Furthermore, after accounting for all environmental variables, part of the unexplained variance in the endemic species richness is explained by the introduced species richness and vice‐versa. That is, areas with high levels of endemic species richness had many introduced species. There is evidence of a somewhat inverse spatial distribution between a group of oceanic‐type, forest‐dwelling, endemic, relict arthropods and a group of more generalist endemic arthropods that are able to survive in disturbed marginal sites particularly rich in non‐indigenous species.Main conclusions Richness of endemic species is mainly driven by abiotic factors such as a climatic axis (oceanic‐type localities with lower temperatures and summer precipitations) and a binary variable CALD (location of sites in caldeiras or ravines), whereas richness of introduced species depends on disturbance related factors. However, after factoring out these major influences, there is a correlation between endemic and introduced richness, suggesting that – independent of the environmental and geographical factors that affect the distribution of endemic or introduced species – the richest endemic assemblages are more prone to invasion, due probably to a facilitation process. Inconclusive evidence suggests that non‐indigenous species are limited to those sites under anthropogenic influence located mainly near forest edges, but the rate of expansion of those species to high‐altitude, core pristine sites has still to be tested.
People withMECP2mutation‐positive Rett disorder who converse
Authors: Kerr A. M. , Archer H. L. , Evans J. C. , Prescott R. J. , Gibbon F. 
Published: December 2005

AbstractBackground People with useful speech after regression constitute a distinct group of those with mutation‐positive Rett disorder, 6% (20/331) reported among mutation‐positive people in the British Survey. We aimed to determine the physical, mental and genetic characteristics of this group and to gain insight into their experience of Rett syndrome.Methods Clinical and molecular data for people with Rett, aged 10 or more years at follow‐up (the study group,n = 13), with the ability to converse and aMECP2mutation are presented. They were compared with an age‐matched control group (n = 110), who could not converse and had a pathogenicMECP2mutation.Results The study group differed significantly from the control group with regard to their disease severity (P < 0.001); feeding difficulty scores (P < 0.001); health scores (P < 0.001); epilepsy (P < 0.001); head circumference (P < 0.004); age at onset of the regression period (P < 0.001) (six in the study group did not regress) and mutation frequency (C‐terminal deletionsP = 0.014, R133CP < 0.006). The results indicate that favourable skewing of X‐inactivation is only present in a small proportion of mild cases. Speech was fragmented with a soft, breathless quality, and all but two had obviously irregular breathing. One person with an R168X mutation preferred signing to speech. All enjoyed interpersonal contact, showing affection and preferring people to objects, clearly distinguishing the condition from autism. Most were habitually anxious. Music was a source of pleasure and relaxation also providing a valuable educational asset. Even in these most able cases, understanding was severely restricted in most and little initiative was shown.Conclusions While the Rett profile is present in these people they are commonly not classic, and the presence of speech, good head growth and lack of regression may lead to missed diagnoses. A strong association was demonstrated between this milder form of the disease and R133C and C‐terminal deletions.
Progesterone Treatment of Adult Male Rats Suppresses Arginine Vasopressin Expression in the Bed Nucleus of the Stria Terminalis and the Centromedial Amygdala
Authors: Auger C. J. , Vanzo R. J. 
Published: December 2005

AbstractThe steroid sensitive vasopressin cells of the bed nucleus of the stria terminalis (BST) and centromedial amygdala (CMA) are involved in numerous behavioural and physiological functions. These cells are known to be greatly influenced by gonadal steroids. Castration reduces and testosterone replacement restores arginine vasopressin (AVP)‐immunoreactive (‐ir) labelling and AVP mRNA expression in the BST and CMA. Gonadal steroids appear to act directly in AVP‐expressing cells within the BST and CMA, because the majority of AVP‐ir cells in these areas contain oestrogen and androgen receptor immunoreactivity. Recently, we have localised progestin receptor immunoreactivity in virtually all of the AVP‐ir cells in the BST and CMA. To understand the role played by progestin receptors in AVP cells within the BST and CMA, we treated male rats with 1 mg of progesterone or oil for 5 days, and then examined AVP immunoreactivity within the brain. We found that progesterone decreased AVP‐ir labelling within the BST and CMA, as well as in two of the projection sites of these cells, the lateral septum and lateral habenula. Progesterone treatment did not alter testosterone secretion from the testes, nor did it alter adult male sexual behaviour. These data illustrate an additional mechanism by which the AVP cells in the BST and CMA can be regulated. These data also suggest that progesterone may act in the male brain to influence behaviours that are AVP‐dependent.
GABAB Receptor‐Activation Inhibits GABAergic Synaptic Transmission in Parvocellular Neurones of Rat Hypothalamic Paraventricular Nucleus
Authors: Liu X. , Tribollet E. , Raggenbass M. 
Published: December 2005

AbstractThe paraventricular nucleus of the hypothalamus contains three classes of neurones: (i) magnocellular and (ii) parvocellular neurosecretory neurones and (iii) nonendocrine projection neurones. The present study aimed to determine whether functional GABAB receptors are present on axon terminals that synapse with parvocellular neurosecretory and nonendocrine paraventricular neurones and to determine how activation of GABAB receptors control GABAergic input to these neurones. Whole‐cell recordings were performed in coronal hypothalamic slices of the rat containing the paraventricular nucleus. GABAA receptor–mediated inhibitory postsynaptic currents (i.p.s.c.) were isolated pharmacologically in the presence of antagonists of glutamatergic ionotropic receptors. We found that baclofen, an agonist of GABAB receptors, decreased the frequency of spontaneous and miniature i.p.s.c. It also decreased the amplitude of evoked i.p.s.c. These effects were suppressed by CGP55845A, a competitive antagonist of GABAB receptors. CGP55845A also increased the frequency of miniature i.p.s.c. and the amplitude of evoked i.p.s.c., suggesting that, in physiological conditions, presynaptic GABAB receptors exert a tonic inhibition on GABA release. Baclofen had no effect on GABA‐evoked postsynaptic currents, suggesting that the baclofen‐dependent suppression of GABAergic i.p.s.c. was exclusively due to a presynaptic action of the agonist. Our data indicate that GABAB receptors are present on axon terminals of GABAergic presynaptic neurones contacting parvocellular neurosecretory and nonendocrine paraventricular neurones, and suggest that GABAB receptors exert a tonic inhibition of GABA release from GABAergic terminals. Activation of these receptors causes disinhibition of parvocellular neurosecretory and nonendocrine paraventricular neurones.
Influence of hydrogeographic history and hybridization on the distribution of genetic variation in the pupfishesCyprinodon atrorusandC. bifasciatus
Authors: CARSON EVAN W. , DOWLING THOMAS E. 
Published: December 2005

AbstractThe evolutionary importance of hybridization in animals has been subject of much debate. In this study, we examined the influence of hydrogeographic history and hybridization on the present distribution of nuclear and mitochondrial DNA variation in two pupfish species,Cyprinodon atrorusandCyprinodon bifasciatus. Results presented here indicate that there has been limited introgression of nuclear genes; however, mtDNA introgression has been substantial, with complete replacement of theC.bifasciatusmitochondrial genome by that ofC.atrorus. Subsequent to this replacement, there has been diversification of mitochondrial haplotypes along major geographic regions in the basin. Evidence was also found that mitochondrial replacement follows a predictable, cyclical pattern in this system, with isolation and diversification followed by re‐contact and replacement ofC.bifasciatusmitochondrial haplotypes by those ofC.atrorus. This pattern is best explained by a combination of a numeric bias towardsC.atrorusand mating site selection rather than selection forC.atrorusmitochondrial genome. These results demonstrate the important role hybridization can play in evolution.
The cell surface expression of group 2 capsular polysaccharides in Escherichia coli: the role of KpsD, RhsA and a multi‐protein complex at the pole of the cell
Authors: McNulty Clodagh , Thompson James , Barrett Brendan , Lord Liz , Andersen Christian , Roberts Ian S. 
Published: December 2005

SummaryThe export of large negatively charged capsular polysaccharides across the outer membrane represents a significant challenge to Gram negative bacteria. In the case of Escherichia coli group 2 capsular polysaccharides, the mechanism of export across the outer membrane was unknown, with no identified candidate outer membrane proteins. In this paper we demonstrate that the KpsD protein, previously believed to be a periplasmic protein, is an outer membrane protein involved in the export of group 2 capsular polysaccharides across the outer membrane. We demonstrate that KpsD and KpsE are located at the poles of the cell and that polysaccharide biosynthesis and export occurs at these polar sites. By in vivo chemical cross‐linking and MALDI‐TOF‐MS analysis we demonstrate the presence of a multi‐protein biosynthetic/export complex in which cytoplasmic proteins involved in polysaccharide biosynthesis could be cross‐linked to proteins involved in export across the inner and outer membranes. In addition, we show that the RhsA protein, of previously unknown function, could be cross‐linked to the complex and that a rhsA mutation reduces K5 biosynthesis suggesting a role for RhsA in coupling biosynthesis and export.
Iron acquisition systems for ferric hydroxamates, haemin and haemoglobin in Listeria monocytogenes
Authors: Jin Bo , Newton Salete M. C. , Shao Yi , Jiang Xiaoxu , Charbit Alain , Klebba Phillip E. 
Published: December 2005

Summary Listeria monocytogenes is a Gram‐positive bacterium that causes severe opportunistic infections in humans and animals. We biochemically characterized, for the first time, the iron uptake processes of this facultative intracellular pathogen, and identified the genetic loci encoding two of its membrane iron transporters. Strain EGD‐e used iron complexes of hydroxamates (ferrichrome and ferrichrome A, ferrioxamine B), catecholates (ferric enterobactin, ferric corynebactin) and eukaryotic binding proteins (transferrin, lactoferrin, ferritin, haemoglobin). Quantitative determinations showed 10–100‐fold lower affinity for ferric siderophores (Km ≈ 1–10 nM) than Gram‐negative bacteria, and generally lower uptake rates. Vmax for [59Fe]‐enterobactin (0.15 pMol per 109 cells per minute) was 400‐fold lower than that of Escherichia coli. For [59Fe]‐corynebactin, Vmax was also low (1.2 pMol per 109 cells per minute), but EGD‐e transported [59Fe]‐apoferrichrome similarly to E. coli (Vmax = 24 pMol per 109 cells per minute). L. monocytogenes encodes potential Fur‐regulated iron transporters at 2.031 Mb (the fur‐fhu region), 2.184 Mb (the feo region), 2.27 Mb (the srtB region) and 2.499 Mb (designated hupDGC region). Chromosomal deletions in the fur‐fhu and hupDGC regions diminished iron uptake from ferric hydroxamates and haemin/haemoglobin respectively. In the former locus, deletion of fhuD (lmo1959) or fhuC (lmo1960) strongly reduced [59Fe]‐apoferrichrome uptake. Deletion of hupC (lmo2429) eliminated the uptake of haemin and haemoglobin, and decreased the virulence of L. monocytogenes 50‐fold in mice. Elimination of srtB region genes (Δlmo2185, Δlmo2186, Δlmo2183), both sortase structural genes (ΔsrtB, ΔsrtA, ΔsrtAB), fur and feoB did not impair iron transport. However, deletion of bacterioferritin (Δfri, lmo943; 0.97 Mb) decreased growth and altered iron uptake: Vmax of [59Fe]‐corynebactin transport tripled in this strain, whereas that of [59Fe]‐apoferrichrome decreased 20‐fold.
Interactions between the YycFG and PhoPR two‐component systems in Bacillus subtilis: the PhoR kinase phosphorylates the non‐cognate YycF response regulator upon phosphate limitation
Authors: Howell Alistair , Dubrac Sarah , Noone David , Varughese Kottayil I. , Devine Kevin 
Published: December 2005

SummaryTwo‐component signal transduction systems (TCS) are an important mechanism by which bacteria sense and respond to their environment. Although each two‐component system appears to detect and respond to a specific signal(s), it is now evident that they do not always act independently of each other. In this paper we present data indicating regulatory links between the PhoPR two‐component system that participates in the cellular response to phosphate limitation, and the essential YycFG two‐component system in Bacillus subtilis. We show that the PhoR sensor kinase can activate the YycF response regulator during a phosphate limitation‐induced stationary phase, and that this reaction occurs in the presence of the cognate YycG sensor kinase. Phosphorylation of YycF by PhoR also occurs in vitro, albeit at a reduced level. However, the reciprocal cross‐phosphorylation does not occur. A second level of interaction between PhoPR and YycFG is indicated by the fact that cells depleted for YycFG have a severely deficient PhoPR‐dependent phosphate limitation response and that YycF can bind directly to the promoter of the phoPR operon. YycFG‐depleted cells neither activate expression of phoA and phoPR nor repress expression of the essential tagAB and tagDEF operons upon phosphate limitation. This effect is specific to the PhoPR‐dependent phosphate limitation response because PhoPR‐independent phosphate limitation responses can be initiated in YycFG‐depleted cells.
A major protein component of the Bacillus subtilis biofilm matrix
Authors: Branda Steven S. , Chu Frances , Kearns Daniel B. , Losick Richard , Kolter Roberto 
Published: December 2005

SummaryMicrobes construct structurally complex multicellular communities (biofilms) through production of an extracellular matrix. Here we present evidence from scanning electron microscopy showing that a wild strain of the Gram positive bacterium Bacillus subtilis builds such a matrix. Genetic, biochemical and cytological evidence indicates that the matrix is composed predominantly of a protein component, TasA, and an exopolysaccharide component. The absence of TasA or the exopolysaccharide resulted in a residual matrix, while the absence of both components led to complete failure to form complex multicellular communities. Extracellular complementation experiments revealed that a functional matrix can be assembled even when TasA and the exopolysaccharide are produced by different cells, reinforcing the view that the components contribute to matrix formation in an extracellular manner. Having defined the major components of the biofilm matrix and the control of their synthesis by the global regulator SinR, we present a working model for how B. subtilis switches between nomadic and sedentary lifestyles.
New insights into the pneumococcal fratricide: relationship to clumping and identification of a novel immunity factor
Authors: Håvarstein Leiv Sigve , Martin Bernard , Johnsborg Ola , Granadel Chantal , Claverys Jean‐Pierre 
Published: December 2005

SummaryIn 1971, Tomasz and Zanati discovered that competent pneumococci have a tendency to form aggregates when pelleted by centrifugation and resuspended in 0.01 N HCl by brief vortexing. Interestingly, no clumping was observed with parallel cultures of non‐competent cells treated in the same way. We set out to elucidate the mechanism behind this striking phenomenon, and were able to show that it depends on extracellular DNA that is presumably released by so‐called competence‐induced cell lysis. Competence‐induced cell lysis, which was first described a few years ago, seems to rely on the concerted action of several murein hydrolases. Our results confirmed and extended previous findings by showing that competence‐induced aggregation is abolished in a lytA–lytC double mutant, and absolutely requires CbpD and its N‐terminal CHAP amidase domain. Furthermore, we discovered a novel competence stimulating peptide (CSP)‐induced immunity protein, encoded by the early competence gene comM (spr1762), which protects competent pneumococci against their own lysins. Together, the murein hydrolases and the immunity protein constitutes a CSP‐controlled mechanism that allows competent pneumococci to commit fratricide by killing non‐competent pneumococci sharing the same ecological niche. Through such predatory behaviour, pneumococci can get access to transforming DNA and nutrients, promote the release of virulence factors, and at the same time get rid of competitors.