bluuebunny/crossref_metadata_2025 huggingface dataset:
Citrobacter rodentiuminfection causes iNOS-independent intestinal epithelial dysfunction in mice
Authors: Skinn Andrew C. , Vergnolle Nathalie , Zamuner Stella R. , Wallace John L. , Cellars Laurie , MacNaughton Wallace K. , Sherman Philip M.
Published: May 2007

Attaching-effacing bacteria are major causes of infectious diarrhea in humans worldwide. Citrobacter rodentium is an attaching-effacing enteric pathogen that causes transmissible murine colonic mucosal hyperplasia. We characterized colonic inflammation and ion transport at 3, 7, 10, 30, and 60 d after infection of C57Bl/6 mice with C. rodentium. Macroscopic damage score was significantly increased 7 and 10 d after infection. Colonic wall thickness was increased at 7, 10, 30, and 60 d. Myeloperoxidase (MPO) activity was significantly increased at 3, 7, and 10 d and returned to control levels by days 30 and 60. The expressions of inducible nitric oxide synthase and cyclooxygenase-2 were increased by C. rodentium infection. Significant reductions in the epithelial secretory response to carbachol, but not to electrical field stimulation or forskolin, were observed at 3 and 10 d of infection. Translocation of enteric bacteria into the mesenteric lymph nodes was observed 10 d following infection. There was no difference in response to infection between animals deficient in inducible nitric oxide synthase and wild-type controls. The COX-2 inhibitor rofecoxib caused decreased wall thickness and MPO activity at day 10. However, COX-2 inhibition did not alter infection-induced changes in ion transport. Citrobacter rodentium infection causes colonic inflammation, mucosal hyperplasia, and nitric-oxide-independent epithelial dysfunction in association with increased permeability to luminal bacteria.
The role of Granzyme B in atheromatous diseasesThis paper is one of a selection of papers published in this Special Issue, entitled Young Investigators' Forum.
Authors: Chamberlain Ciara M. , Granville David J.
Published: May 2007

The mechanism and role of apoptotic cell death in the pathogenesis of atheromatous diseases is an area of intense research. Atherosclerosis is an inflammatory disease and as such, immune-mediated cell killing plays an important role. Recent studies have suggested that Granzyme B and perforin play an important role in atherogenesis. The current manuscript reviews our current understanding pertaining to the role of Granzyme B in cardiac allograft vasculpathy and atherosclerosis.
Type 2 diabetes and cardiovascular disease: getting to the fat of the matterThis paper is one of a selection of papers published in this Special Issue, entitled Young Investigators' Forum.
Authors: Goralski Kerry B. , Sinal Christopher J.
Published: May 2007

The increasing national prevalence of obesity is a major public health concern and a substantial burden on the health care resources of Canada. In addition to the direct health impact of obesity, this condition is a well-established risk factor for the development of various prevalent comorbidities including type 2 diabetes, hypertension, and cardiovascular disease. Historically, adipose tissue has been regarded primarily as an organ for energy storage. However, the discovery of leptin in the mid 1990’s revolutionized our understanding of this tissue and has focused attention on the endocrine function of adipose tissue as a source of secreted bioactive peptides. These compounds, collectively termed adipokines, regulate a number of biological functions including appetite and energy balance, insulin sensitivity, lipid metabolism, blood pressure, and inflammation. The physiological importance of adipokines has led to the hypothesis that changes in the synthesis and secretion of these compounds in the obese are a causative factor contributing to the development of obesity and obesity-related diseases in these individuals. Following from this it has been proposed that pharmacologic manipulation of adipokine levels may provide novel effective therapeutic strategies to treat and prevent obesity, type 2 diabetes, and cardiovascular disease.
Variability in asthma: symptom perception, care, and outcomesThis paper is one of a selection of papers published in this Special Issue, entitled Young Investigators' Forum.
Authors: Lougheed M. Diane
Published: May 2007

Asthma remains a global respiratory health concern. Substantial variations in asthma outcomes persist in Canada despite the dissemination of national management guidelines. Many factors and their interactions presumably contribute to variations in outcomes, including asthma prevalence, severity, symptom recognition, self-management behaviour, access to care, and management. This article reviews the physiology of symptom perception in asthma, specifically the role of dynamic lung hyperinflation (DH) on the perception of the intensity and quality of dyspnea in asthma, and the link between blunted perception and life-threatening asthma. Additionally, the magnitude and correlates of regional variation in emergency department visit rates and hospitalizations for asthma in Ontario are reviewed.
The public health and safety consequences of sleep disordersThis paper is one of a selection of papers published in this Special Issue, entitled Young Investigators' Forum.
Authors: Sigurdson Krista , Ayas Najib T.
Published: May 2007

Sleep deprivation and medical disorders of sleep are common in today’s society and have significant public health implications. In this article, we address 3 specific issues related to the public health and safety consequences of sleep disorders. First, we review data that has linked sleep restriction to a variety of adverse physiologic and long-term health outcomes including all-cause mortality, diabetes, and cardiovascular disease. Second, we will review recent data that has demonstrated that therapy for obstructive sleep apnea (the most common respiratory disorder of sleep) is an extremely efficient use of healthcare resources (in terms of dollars spent per quality adjusted life year gained), and compares favorably with other commonly funded medical therapies. Finally, we will review data that illustrate the potential adverse patient and occupational safety impacts of the extreme work schedules of housestaff (physicians in training).
Therapeutic potential of the epidermal growth factor receptor transactivation in hypertension: a convergent signaling pathway of vascular tone, oxidative stress, and hypertrophic growth downstream of vasoactive G-protein-coupled receptors?This paper is one of a selection of papers published in this Special Issue, entitled Young Investigators' Forum.
Authors: Fernandez-Patron Carlos
Published: May 2007

The concurrence of enhanced vascular tone, oxidative stress, and hypertrophic growth is a hallmark of hypertension, the condition characterized by sustained elevated blood pressure. However, it is unclear how and why such apparently distinct processes coincide in hypertension. Elevated levels of certain vasoactive G-protein-coupled receptor agonists (such as catecholamines, endothelin-1, and angiotensin II) can explain, at least in part, the development and progression of many hypertensive disorders. Here, we review findings made by other investigators and ourselves suggesting that enhanced vascular tone, oxidative stress, and hypertrophic growth characteristically induced by these agonists involve the transactivation of growth factor receptors. The first step in this transactivation mechanism is agonist-induced activation of metalloproteinase-dependent shedding of growth factors. Shed growth factors then trigger intracellular signaling cascades necessary for growth, production of reactive oxygen species, and maintenance of vascular tone. If this hypothesis is proven generally correct, then transactivation blockers have general therapeutic potential in hypertension regardless of the causative agonist.
Insights into the change in brain natriuretic peptide after ST-elevation myocardial infarction (STEMI): why should it be better than baseline?This paper is one of a selection of papers published in this Special Issue, entitled Young Investigators' Forum.
Authors: Ezekowitz Justin A. , Théroux Pierre , Welsh Robert , Bata Iqbal , Webb John , Armstrong Paul W.
Published: May 2007

While baseline N-terminal brain natriuretic peptide (NT-proBNP) is useful in the prognosis of acute ST-elevation myocardial infarction (STEMI), it is unclear whether a relationship exists between serial NT-proBNP, reperfusion success, and prognosis. We prospectively defined a NT-proBNP analysis in the WEST (Which Early ST-elevation myocardial infarction Therapy) trial that enrolled 304 acute STEMI patients. NT-proBNP (pg/mL) was measured at baseline prior to treatment (n = 258) and 72 to 96 h (n = 247) and 30 days (n = 221) after treatment (ΔNT-proBNP = 72 h value – the baseline NT-proBNP). Reperfusion success was measured by ST-segment resolution at 180 min, infarct size by peak creatine kinase (CK) during the first 24 h, and QRS score at discharge (QRSd). The primary endpoint was a 30 day clinical composite. The ability of either baseline NT-proBNP or ΔNT-proBNP to predict the primary endpoint was compared using single-variable logistic regression and the c-statistic. Median (interquartile range) NT-proBNP in pg/mL was 87 (39–316) at baseline, 864 (338–1857) at 72 h, and 585 (264–1212) at 30 days. ST resolution was inversely correlated with ΔNT-proBNP (r = –0.23, p = 0.002) and 30 day NT-proBNP (30 day NT-proBNP 1016, 828, and 397 for <30%, 30%–70%, ≥70% STR, respectively, p < 0.001). Infarct size was correlated with ΔNT-proBNP by CK (r = 0.41, p < 0.001) and QRSd (r = 0.31, p < 0.001); the 30 day NT-proBNP relationship was similar for CK (r = 0.48, p < 0.001) and QRSd (p = 0.003). The baseline NT-proBNP was associated with an increased 30-day composite endpoint (Q1, 19%; Q2, 20%; Q3, 15%; Q4, 38%; p = 0.03 for trend) as was ΔNT-proBNP (Q1, 16%; Q2, 18%; Q3, 19%; Q4, 37%; p = 0.009 for trend). The c-statistic for baseline, 72 to 96 h, and ΔNT-proBNP was 0.59, 0.61, and 0.62 for the 30-day composite and 0.64, 0.62, and 0.62 for the 90-day composite, respectively. ΔNT-proBNP clearly predicts short-term adverse cardiac events and is superior to baseline NT-proBNP, but similar to the 72 to 96 h NT-proBNP in predicting clinical events after STEMI. This likely reflects the variability in NT-proBNP at presentation and the ability to integrate subsequent important physiologic sequelae of STEMI such as reperfusion and infarct size.
Bovine lactoferrin protects lipopolysaccharide-induced diarrhea modulating nitric oxide and prostaglandin E2 in mice
Authors: Talukder M. Jamilur R. , Harada Etsumori
Published: May 2007

Lactoferrin (Lf), an iron-binding multifunctional glycoprotein, is abundantly present in colostrum and milk of different species such as humans, bovines, and mice. Our previous observation revealed that bovine colostral Lf is transported into the systemic circulation and cerebrospinal fluid from gut-lumen through receptor-mediated transcytosis in calves. Diarrhea caused by Escherichia coli is one of the important causes of infant morbidity and mortality in developing countries. We investigated the effects of bovine lactoferrin (BLf) on lipopolysaccharide (LPS)-induced diarrheogenic activity, gastrointestinal transit (GIT), and intestinal fluid content in mice. LPS accumulated abundant fluid in the small intestine in a dose-dependent manner, induced diarrhea, but decreased the GIT. Pretreatment with BLf significantly attenuated the effects of LPS on the diarrheogenic activity and intestinal content, but reversed the GIT when compared with NG-nitro-l-arginine-methyl ester (L-NAME, a non-selective NOS inhibitor) or indomethacin (an inhibitor of prostaglandin synthesis). Both plasma NO and PGE2 in enterocytes were found to increase in LPS-treated mice and were reversed by BLf. These findings demonstrate that the action of BLf against LPS was specific and it exerts antidiarrheal activity through modulating the cyclooxygenase [NO and PGE2] pathway in the gut.
Beneficial effects of carvedilol as a concomitant therapy to angiotensin-converting enzyme inhibitor in patients with ischemic left ventricular systolic dysfunction
Authors: Gandhi Purvi S. , Goyal Ramesh K. , Jain Anil R. , Mallya B. Srinivas , Gupta Vishal M. , Shah Dhiren S. , Trivedi Bharat R. , Shastri Naman A. , Mehta Chirag B. , Jain Kalpana A. , Bhavasar Niren S. , Shah Urmi J.
Published: May 2007

Studies are scant on the effects of short-term carvedilol treatment as an adjuvant to angiotensin-converting enzyme (ACE) inhibitor in patients with left ventricular (LV) systolic dysfunction. The objective of this study was to find the effects of short-term treatment of carvedilol on patients with ischemic LV systolic dysfunction (defined as LV ejection fraction (LVEF) ≤30% on 2D echocardiography) undergoing coronary artery bypass surgery (CABG). There were 74 patients that received ACE inhibitor without any β-blocker (control) and 67 patients that received carvedilol in addition to ACE inhibitor following CABG (carvedilol group). After 1 month of drug administration following CABG, the control group was found to have significantly greater percent improvement in LVEF (29.1% ± 5.39%) as compared with the carvedilol group (15.3% ± 4.89%). However, after 3 and 6 months, LVEF levels were found to be significantly greater in the carvedilol group as compared with the control group. Further, at 6 months of drug administration, LV end systolic diameter was significantly less in the carvedilol group (39.11 ± 1.10 mm) as compared with the control group (43.49 ± 1.39 mm). Thus, carvedilol produces beneficial effect on short-term administration in terms of LV contractility when given along with ACE inhibtior as compared with ACE inhibitor therapy alone.
Combining ursodeoxycholic acid or its NO-releasing derivative NCX-1000 with lipophilic antioxidants better protects mouse hepatocytes against amiodarone toxicity
Authors: Ouazzani-Chahdi Amine , Elimadi Aziz , Chabli Allal , Spénard Jean , Colin Patrick , Haddad Pierre S.
Published: May 2007

Nonalcoholic steatohepatitis (NASH) is a common and potentially severe form of liver disease. This study aimed to determine the effect of ursodeoxycholic acid and its NO-releasing derivative NCX-1000 alone or in combination with antioxidants on cultured mouse hepatocytes treated with amiodarone to mimic certain aspects of hepatocyte injury found in NASH. Isolated mouse hepatocytes were incubated with ursodeoxycholic acid or NCX-1000 (0–100 μmol/L) combined or not combined with the hydrophilic antioxidants butylated hydroxytoluene and ascorbic acid (0–100 μmol/L) or with the lipophilic antioxidant α-tocopherol (0–100 μmol/L) 15 min before adding amiodarone (50 μmol/L) to the culture medium. Twenty hours later, necrosis, apoptosis, superoxide anion production, and malondialdehyde levels were assessed in cultured cells. Amiodarone led to a dose-dependent decrease in cell viability with an LD50of 50 μmol/L and increased production of superoxide anion and lipid peroxidation. NCX-1000 showed a better protective potential than ursodeoxycholic acid against the toxic effects of amiodarone. The hydrophilic antioxidants had no effect on the toxicity of amiodarone, whereas α-tocopherol at a concentration >100 μmol/L almost completely suppressed it. Ursodeoxycholic acid and NCX-1000 protection was additive only when they were combined with α-tocopherol, not with butylated hydroxytoluene or ascorbic acid. In addition, all the antioxidants tested reduced the superoxide anion detected, but only α-tocopherol prevented lipid peroxidation induced by amiodarone. The combination of lipophilic antioxidants with ursodeoxycholic acid or NCX-1000 enhances their protective potential and could represent an interesting therapeutic approach to explore for the treatment of NASH.
Altered PKC expression and phosphorylation in response to the nature, direction, and magnitude of mechanical stretch
Authors: Bullard Tara A. , Hastings Joshua L. , Davis Jeffrey M. , Borg Thomas K. , Price Robert L.
Published: May 2007

Protein kinase C (PKC) isozymes have been shown to play a role in mechanotransduction in a variety of cell types. We sought to identify the PKC isozymes involved in transducing mechanical (cyclic vs. static), direction and intensity of stretch by examining changes in protein expression and phosphorylation. We used a 3-dimensional culture system with aligned neonatal rat cardiac myocytes on silastic membranes. Myocytes were subjected to either cyclic stretch at 5 cycles/min or static stretch for a period of 24 h at intensities of 0%, 2.5%, 5%, or 10% of full membrane length. Stretch was applied in perpendicular or parallel directions to myocyte alignment. PKC δ was most sensitive to stretch applied perpendicular to myocyte alignment regardless of the nature of stretch, while phospho PKC δ T505 increased in response to static-perpendicular stretch. PKC ε expression was altered by cyclic stretch but not static stretch, while phospho PKC ε S719 remained unchanged. PKC α expression was not altered by stretch; however, phospho PKC α S657 increased in a dose-dependent manner following cyclic-perpendicular stretch. Our results indicate that changes in PKC expression and phosphorylation state may be a mechanism for cardiac myocytes to discriminate between the nature, direction, and intensity of mechanical stretch.
Effect of browse on post-ingestive energy loss in an Arctic ruminant: implications for muskoxen (Ovibos moschatus) in relation to vegetation change
Authors: Lawler James P. , White Robert G.
Published: May 2007

Shrubs are predicted to dominate tundra with warmer temperatures at northern latitudes. We tested the null hypothesis that addition of browse to a graminoid diet would not alter post-ingestive energy loss in muskoxen ( Ovibos moschatus (Zimmermann, 1780)). Energy losses over 8 h following feeding were used to test our hypothesis. Willows ( Salix alaxensis (Anderss.) Coville, Salix planifolia ssp. pulchra (Cham.) Argus) and birch ( Betula nana L.) (twigs in winter, leaves in summer) were separately mixed at graded levels (0%, 20%, 40%, 60%, and 80%) with chopped hay ( Bromus inermis Leyss.) and fed as single meals to muskoxen. Meals containing ≥60% browse were often partially or completely rejected. Meals containing 20%–60% woody or leafy S. alaxensis or S. p. pulchra resulted in higher energy expenditure than meals of 100% hay. Meals containing 20%–60% woody B. nana tended to decrease energy expenditure relative to 100% hay, while 20%–60% leafy B. nana was similar to 100% hay. We conclude there is an energy cost associated with consuming browse. This cost varies by browse species and type. Since muskoxen tolerated up to 40% browse in the diet, this cost may be within their ecological tolerance. This tolerance has important implications under global warming scenarios.
The good mother: Does nest-site selection constitute parental investment in turtles?
Authors: Hughes E.J. , Brooks R.J.
Published: May 2007

We tested the hypothesis that female midland painted turtles ( Chrysemys picta marginata Agassiz, 1857) provide significant parental care to their offspring through their choice of nest site. Painted turtle nest sites can be described in relation to specific microhabitat characteristics that, because of their effects on soil microclimate, may influence survival to hatch. We created models of the relationships between nest-site microhabitat and nest-site selection and between nest-site microhabitat and survival to hatch, and judged the fit of the models using Akaike’s information criterion corrected for small sample sizes. Female painted turtles selected nest sites with little canopy cover, little understory vegetation, and a southwestern slope aspect. Increased survival to hatch was associated with decreased organic content, which may serve as a surrogate for little or no vegetation or canopy cover. Nests in sites selected by turtles had slightly higher survival to hatch rates than nests in randomly chosen sites, suggesting that turtles may choose nest sites which increase offspring survival. Selection of nest sites may constitute significant parental investment and should be considered in studies of turtle life history.
Impact of puma predation on the decline and recovery of a mule deer population in southeastern Idaho
Authors: Laundré J.W. , Hernández L. , Clark S.G.
Published: May 2007

We modeled the impact of puma ( Puma concolor (L., 1771)) predation on the decline and recovery of mule deer ( Odocoileus hemionus (Rafinesque, 1817)) in southern Idaho based on estimates of puma numbers, predation rates of pumas, and reproductive variables of deer. Deer populations peaked in 1992–1993, then declined more than 55% and remained low for the next 11 years. Puma numbers peaked 4–6 years after deer populations peaked but then declined to original levels. Estimated puma predation on the deer population before and after the decline was 2.2%–3.3% and 3.1%–5.8%, respectively. At high puma densities (>3 pumas/100 km2), predation by pumas delayed deer recovery by 2–3 years. Percent winter mortality of fawns (r2 = 0.62, P < 0.001) and adult female deer (r2 = 0.68, P < 0.001) correlated positively with December–January snowfall. Incorporation of winter snowfall amounts in the model produced a pattern of deer population change matching estimated changes based on field survey data. We conclude that pumas probably were a minor factor in the decline of the deer population in our area and did not suppress deer recovery. We propose that winter snowfall was the primary ultimate and proximate factor in the deer decline and suppression of their recovery.
Escape tactics of two syntopic forms of the Lacerta perspicillata complex with different colour patterns
Authors: Carretero Miguel A. , Vasconcelos Raquel , Fonseca Miguel , Kaliontzopoulou Antigoni , Brito José C. , Harris D. James , Perera Anna
Published: May 2007

It has been suggested that dorsal colour patterns and defence strategies could have coevolved in reptiles, the striped species being more prone to flee compared with the spotted species that rely more on crypsis. Because of the confounding effects of phylogeny and habitat, we compared closely related forms that share the same habitats and predation pressures but display different patterns. The spotted (chabanaudi) and the striped (pellegrini) forms of the Lacerta perspicillata (= Teira perspicillata ) Duméril and Bibron, 1839 complex are reproductively isolated in a locality where they live in syntopy. The responses of lizards to a direct attack by a predator, simulated by the approach of a researcher, were investigated. Both forms displayed divergent antipredatory behaviours (escaping and recovering) to optimize survival. Chabanaudi lizards showed longer approach distances and took more time to abandon shelter than pellegrini lizards when the effects of temperature and of distance fled were removed. Reappearance was related with previous flight in chabanaudi but with thermal quality of the refuge in pellegrini. Although both used similar refuges, chabanaudi selected bigger rocks that were less accessible to terrestrial predators but were more prone to bird attacks, whereas pellegrini selected fragmented rocks that faced more terrestrial predation. Our results support the hypothesis of coevolution between pattern and antipredatory behaviour.
Eggs of spruce grouse dry at a faster rate than those of ruffed grouse
Authors: Bendell James F. , Bendell–Young L.I.
Published: May 2007

We measured the rate of water loss and pore density of eggs of spruce grouse ( Canachites canadensis canace (L., 1766)) and ruffed grouse ( Bonasa umbellus togata (L., 1766)) from different parts of their range in Ontario. Eggs were dried in enclosed glass jars over Drierite®and in paper trays in open air at room temperature and humidity. Eggs were weighed to the nearest 0.01 g every 2–4 days and the change in mass was measured as water loss. Pores of shells were counted (pores/cm2) in the blunt, middle, and pointed sections of the egg. Eggs of spruce grouse lost water at a faster rate in Drierite®and in open air and had a greater density of pores than eggs of ruffed grouse. Rates of water loss were constant and varied inversely with ambient humidity, with the difference between species greatest in open air. Eggs late in incubation of ruffed grouse dried at a faster rate than those early in incubation in Drierite®. The adaptations of eggs of each grouse to the moisture of the nest may help explain their distribution, density, and habitat and nest-site selections, as well as behavioural aspects of the nesting hen. Both, especially the spruce grouse, may be good indictors of climate change.
Songs of the Savannah Sparrow: structure and geographic variation
Authors: Sung Ha-Cheol , Handford Paul
Published: May 2007

We investigated song structure and the pattern of geographic variation at the syllable and whole song levels in Savannah Sparrow, Passerculus sandwichensis (J.F. Gmelin, 1789). Songs were recorded for 179 males from eight sample populations distributed along a 230 km transect in southwestern Ontario in 2000. Subsequent analysis included measurement and comparison of structural song features and qualitative analysis of syllable and song type similarity among individuals both within and among populations, by reference to a syllable catalogue based on syllable similarity. Song type sharing within samples was not common, while song dissimilarity significantly correlated with distance among samples. Overall south–north trends appeared in two aspects of quantitative and qualitative characteristics, and the geographic differentiation of Savannah Sparrow songs was gradual, increasing with distance. At a higher level of analysis, two song groups, with qualitatively distinct structures (here termed themes), were identified. These themes showed a clinal intergrade, such that one theme was found in all individuals of the four southern samples, while in the four more northerly samples, the second theme's incidence grew progressively from 20% to 80%. However, birds singing the southern theme in populations dominated by the northern theme nevertheless produced songs that show metrical (frequency and duration) characteristics typical of the northern theme songs from their own population. Cluster analysis based on syllable and song type similarity–dissimilarity between populations linked geographically neighboring populations closely, while populations fell into two main clusters: the three most northerly and the five most southerly populations. The same cluster pattern also appeared within each theme type.
The value of bioelectrical impedance analysis vs. condition indices in predicting body fat stores in North American porcupines (Erethizon dorsatum)
Authors: Barthelmess Erika L. , Phillips Monica L. , Schuckers Michael E.
Published: May 2007

We developed a predictive model to estimate body fat stores in a population of North American porcupines, Erethizon dorsatum (L., 1758). We trapped porcupines in the autumn of 2004 and spring of 2005. After collecting morphometric measurements on each animal, we used a plethysmograph to perform bioelectrical impedance analysis (BIA). We euthanized the subjects, measured two components of body composition (body fat, body water) via direct chemical analysis, and calculated lean dry mass to compare with BIA data. With regression we found the best predictive models for total body water, total body fat, percent body fat, and lean dry mass. We also estimated body condition for each animal using six different condition indices and compared the ability of the condition indices and our regression model to predict total body fat. Our model for total body fat accounted for 84% of the variation in fat measured by direct chemical analysis, and our model for percent body fat accounted for 78% of the variation. Two condition indices were significantly related to total body fat in porcupines and explained 45%–49% of the variation in observed body fat. We recommend BIA as a useful technique for estimating body fat stores in field studies of free-ranging porcupines and suggest abandonment of the use of condition indices as analogues of body fat stores in animal studies unless the indices can first be validated.
Effects of pH, aluminium, and soft water on larvae of the amphibiansBufo bufoandTriturus vulgaris
Authors: Skei Jon K. , Dolmen Dag
Published: May 2007

Larval Bufo bufo (L., 1758) and Triturus vulgaris (L., 1758) were exposed to soft water (0.5 mg·L–1Ca2+) experimentally acidified to pH 3.9 to 5.9 and total aluminium concentrations of <10, 150, and 300 µg·L–1. Below pH 4.5 both species experienced increased mortality. The LC50(168 h) for <10 and 150 µg·L–1Al was pH 4.3 and 4.1 for B. bufo and 4.2 and 4.1 for T. vulgaris. However, Al3+increased the survival of both species, which may be due to the contribution of Al3+to the ionic strength. No B. bufo larvae died at pH >4.5, whereas T. vulgaris at higher Al concentrations suffered relatively high mortality at pH 5.1–5.9, where Al occurs mainly as Al(OH)2+and Al(OH)2+. Unlike external gills (T. vulgaris), internal gills (B. bufo) have their own internal environment and are probably better protected against the presence of these toxic Al species in the water. These Al species thus seem to be toxic to T. vulgaris larvae but not to B. bufo. Chloride was seen to be important for survival in water of low ionic strength, since the survival of T. vulgaris larvae, particularly at low Al concentration, increased at pH levels down to pH 4.3 when the water was acidified with HCl.
Timing of Hexagenia (Ephemeridae: Ephemeroptera) mayfly swarms
Authors: Corkum Lynda D. , Ciborowski Jan J.H. , Dolan David M.
Published: May 2007

Although degree-days can be used to determine when insect emergence begins, peak swarming events in species that exhibit extended emergence periods are difficult to estimate. With the aid of logistic regression, we estimated the probability of adult mayfly swarms (≥50 individuals/m2), occurring on any given night in western Lake Erie, using meteorological data. We sampled adult Hexagenia Walsh, 1863 from 2130 (sunset) to 2300 on 18 dates in 2000 (2 June – 18 July), with the largest numbers retrieved between 13 June and 2 July. Water temperature (20 °C) was the cue to the onset of swarming (subimagos). Highest mean (±SE) density of all Hexagenia adults (subimagos and imagos) was 24 740 ± 8 757 individuals/m2. Overall, 10-fold more imagos (mostly females) than subimagos were attracted to lights. Of the factors examined (air and water temperature, Julian day, dew point, heat index, humidity, moon phase, wind chill, wind direction, wind speed), onshore wind speed (0–9.2 km/h) on calendar dates for which the water temperature exceeded 20 °C was the most significant factor to account for total adult swarms. Eighty-three percent of the 18 swarming events observed in 2000 were correctly predicted. Validity of the model was confirmed with data collected in 2002, during which 5 of 6 swarming events were correctly predicted from the logistic model. Wind promotes adult aggregation at the land–water interface, the effect of which facilitates mating success and predator swamping.
Coyote survival in a row-crop agricultural landscape
Authors: Van Deelen T.R. , Gosselink T.E.
Published: May 2007

With intensive farming, planting and harvest are the primary disturbance factors driving cover dynamics that influence wildlife communities. A top predator, coyotes ( Canis latrans Say, 1823) impact other wildlife when populations are high. Thus, knowledge of coyote demographics in agricultural habitat is critical to understanding ecosystem dynamics. We studied survival of 59 radio-collared coyotes (28 juveniles, 31 adults) from 1996 to 2001 in intensively farmed central Illinois. Logistic regression suggested that age and year were important covariates, but sex was not. Divergence in age-specific Kaplan–Meier survival functions occurred during fall harvest because of higher mortality among juveniles. Annual survival (30 April – 29 April) was 0.59 (95% CI = 0.47–0.71) for adults and 0.13 (0.06–0.20) for juveniles captured after June 1. Shooting (58% of mortality) was the principal cause of mortality, followed by road kills (24%) and other mortalities. Mortality of juveniles following agricultural harvest probably occurs because of inexperience, dispersal through unfamiliar territory, intense human activity, and catastrophic loss of agricultural cover. In contrast, we recorded no shootings of coyotes during the growing season when agricultural cover was highest (14 June – 29 September) despite a year-round open hunting season on coyotes in Illinois.
Secretory material from antennal organs and its possible role in mating behaviour of Pipunculidae (Diptera)
Authors: Belcari A. , Kozánek M.
Published: May 2007

The study of antennal morphology of entomoparasitic flies belonging to the family Pipunculidae (Diptera) revealed the presence of a developed secretory system area on the third antennal segment (flagellum) of pipunculid males. The possible physiological function of this system is discussed. Socketed mechanotactile bristles, two types of basiconical sensilla, one type of grooved sensilla, and a sensory pit form the sensillar system of pipunculid antennae. The morphology of these sensilla and the pattern of their distribution are presented. The discovery of a secretory system in male antennae reveals the possible complex role of antennae in courtship behaviour of pipunculid flies.
First results on the feeding ecology of the Transcaucasian water shrew Neomys teres (Soricomorpha: Soricidae) from Armenia
Authors: Churchfield Sara , Rychlik Leszek , Yavrouyan Eduard , Turlejski Kris
Published: May 2007

Microscopic examination of alimentary tracts of 14 Neomys teres Miller, 1908 from a mountainous region in northern Armenia produced the first data on the diet of this almost unknown species of conservation concern. Twenty-three different prey types were distinguished in summer-caught shrews, all of which were invertebrates (14 terrestrial and 9 aquatic in origin). The dominant dietary items were Coleoptera and Diptera adults, Araneae, Opiliones, and Lumbricidae, as well as freshwater crustaceans and Trichoptera larvae. Prey ranged from <3 to >16 mm in length, but those eaten most frequently were 6–10 mm in length. Although N. teres was captured beside streams and rivers, aquatic prey comprised only 27% of the dietary composition. Despite the morphological similarity of N. teres to Neomys fodiens (Pennant, 1771), its foraging niche more closely resembles that of upland populations of Neomys anomalus Cabrera, 1907 and its reliance on aquatic habitats remains equivocal.
Behavioral roles of the sexually dimorphic structures in the male harvestman, Phalangium opilio (Opiliones, Phalangiidae)
Authors: Willemart Rodrigo H. , Farine Jean-Pierre , Peretti Alfredo V. , Gnaspini Pedro
Published: May 2007

In various animal species, male sexual dimorphic characters may be used during intrasexual contests as ornaments to attract females, or to hold them before, during, or after copulation. In the well-known harvestman, Phalangium opilio L., 1758, the behavioral functions of these male sexually dimorphic structures have never been studied in detail. Therefore, in addition to a morphometric study, 21 male contests and 43 sexual interactions were analyzed. Our observations revealed that during contests, the male cheliceral horns form a surface by which the contestants use to push each other face-to-face while rapidly tapping their long pedipalps against the pedipalps of the opponent, occasionally twisting the opponent’s pedipalp. Scanning electron micrographs revealed contact mechanoreceptors on the pedipalp that would detect the intensity–frequency of contact with the contender’s pedipalp. Larger males won almost all contests, whereas the loser rapidly fled. During sexual interactions, the longer pedipalps of the male held legs IV of the female, whereas males with shorter pedipalps held the female by legs III. No contact with the male pedipalps and chelicerae by the females was visible before, during, or after copulation. Soon after copulating, males typically bent over the female, positioning their cheliceral horns against the females’s dorsum. Consequently, our data show that the cheliceral horns and the longer pedipalps of the male seem to play an important role, during both intersexual and intrasexual encountering.
Do pronghorn (Antilocapra americana) perceive roads as a predation risk?
Authors: Gavin S.D. , Komers P.E.
Published: May 2007

The risk–disturbance hypothesis proposes that organisms respond to generalized threat stimuli; therefore, human disturbances that elicit these behaviours will cause individuals to behave similarly to avoid a natural predator. Studies have shown that pronghorn antelope, Antilocapra americana (Ord, 1815), are influenced by human disturbances. We examined several intensities of human activity and distance from disturbances as indicators of risk perception in pronghorns. We investigated whether pronghorns exhibited risk-avoidance behaviour towards road traffic consistent with the risk–disturbance hypothesis by comparing vigilance and foraging behaviour observations across increasing traffic levels and proximity to roads. Pronghorns showed higher vigilance and lower foraging times along high traffic roads during the spring season compared with lower traffic levels, suggesting that risk perception is related to traffic level. Moreover, individuals within close proximity to roads regardless of traffic level exhibited higher vigilance levels, indicating that there is an overall risk perceived towards roads. Our results also suggest that individuals in herds with young are more risk averse than other social groupings and individuals in larger groups perceive less risk. We suggest that consequences of risk-avoidance behaviour should be reflected in land-use plans that address road densities and traffic levels to better manage wildlife.
What carnivore biologists can learn from bugs, birds, and beavers: a review of spatial theories
Authors: Young Julie K. , Shivik John A.
Published: May 2007

Information on the ecology and evolution of a species can be enhanced by studying spatial ecology. Even though space use has been a focus of carnivore research for decades, the theoretical framework for such studies remains poorly developed. Most spatial ecology theory has instead been developed and tested with invertebrates and expanded into fishery and ornithological research. The goal of this review is to examine spatial theories being tested in other taxonomic groups that could positively influence how carnivore biologists design studies. Details are provided from studies that illustrate methods to quantify space use, and four broad areas of spatial theory are reviewed: conspecific attraction, territory establishment, within-territory space use, and inheritance of space use. Suggestions are given on how carnivore biologists could incorporate each of these components into study designs. Carnivore biologists have opportunities to test spatial theory at small and large scales that could ultimately advance the entire field of spatial ecology. Although this review focuses on improving studies of terrestrial carnivores, our suggestions are relevant for studies of spatial theories across taxa.
Bomb radiocarbon dating calibrates beluga (Delphinapterus leucas) age estimates
Authors: Stewart R.E.A. , Campana S.E. , Jones C.M. , Stewart B.E.
Published: May 2007

The ages of many mammals are estimated by counting growth layers in tooth sections, yet validation of age estimation techniques using free-ranging mammals has been problematic. Contrary to age estimates for most other animals in which it is assumed that one bipartite growth increment forms annually, beluga whale ( Delphinapterus leucas (Pallas, 1776)) age estimates have been calculated assuming that two growth layer groups (GLGs) form each year. Here we report the age validation for belugas based on date-specific incorporation of atomic bomb radiocarbon into tooth GLGs. Radiocarbon assays of dentinal layers formed in belugas harvested between 1895 and 2001 indicated that radiocarbon from atmospheric testing of nuclear weapons was incorporated into growing teeth and retained for the remaining life of the animal. Comparison of age determined by bomb radiocarbon with age determined by GLG counts indicated that GLGs form annually, not semiannually, and provide an accurate indicator of age for belugas up to at least 60 years old. Radiocarbon signatures of belugas were temporally and metabolically stable and were apparently derived more from the radiocarbon content of their prey than from water. Our understanding of many facets of beluga population dynamics is altered by the finding that this species lives twice as long as previously thought.
Stress and parasitism of white-footed mice (Peromyscus leucopus) in dry and floodplain environments
Authors: Brown T.T. , Fuller C.A.
Published: May 2007

We hypothesized that flooding represents an environmental stressor that might affect the corticosterone levels, parasite prevalence, and life history of small mammals living in floodplain environments. We compared populations of white-footed mice ( Peromyscus leucopus (Rafinesque, 1818)) on floodplains and dry areas. We found more males on floodplains (p = 0.008) and more females on dry areas (p = 0.005). There were no differences in mass (p > 0.05) or intestinal parasite prevalence (p = 0.665) between dry and floodplain habitats, but bot fly larvae were significantly more prevalent in males living on floodplains (p = 0.043). Floodplain animals had significantly higher levels of corticosterone than dry-area animals in fall, and lower levels in summer (F[1,20] = 4.483, p = 0.047). In addition, we found that animals with intestinal parasites had higher levels of corticosterone than those that were without parasites (p = 0.014) or that harbored bot fly larvae (p = 0.001). Floodplains seem to be harsher environments than dry areas, but this may be a result of differences in habitat rather than a direct result of flooding.
Site fidelity, migratory behaviour, and spatial organization of female isards (Rupicapra pyrenaica) in the Pyrenees National Park, France
Authors: Crampe J.-P. , Bon R. , Gerard J.-F. , Serrano E. , Caens P. , Florence E. , Gonzalez G.
Published: May 2007

We studied from 1993 to 2002 the spatial organization of visually marked females in an isard ( Rupicapra pyrenaica Bonaparte, 1845) population in the Pyrenees National Park. In winter, all individuals were concentrated within the same 3.7 km2 refuge area. In summer, two patterns of space use were recorded: sedentary females (n = 33; 52.2%) remained within the refuge area, whereas migrating females (n = 29; 46.8%) summered outside the refuge area, at a horizontal distance of 1.4–9.2 km and 300–800 m higher in elevation than their winter ranges. Females were faithful to their seasonal ranges. The population was organized in well-defined spatial units in summer. This organization was roughly preserved in winter, despite the spatial concentration of the individuals by this season. The resulting spatial clustering might reduce spatial competition and pathogenic contamination between groups, allowing the maintenance of high population density. The appearance of a migratory pattern occurred probably as a result of the protected status of the species, which allowed the population to increase. Some individuals dispersed as a result of the population density increase. The two recorded patterns of space use likely arose from spatial attachment and social affinity that developed in the first years of a female’s life, and could explain the coexistence of the two spatial patterns.
Wildfire effects on home range size and fidelity of boreal caribou in Alberta, Canada
Authors: Dalerum Fredrik , Boutin Stan , Dunford Jesse S.
Published: May 2007

Wildfire can rapidly alter the forage availability for boreal ungulates such as woodland caribou ( Rangifer tarandus caribou Gmelin, 1788). Since fire decreases available lichens, a crucial food source for caribou, it may be an important determinant of caribou range use and demography. Here we examined whether wildfire affected range use, habitat selection, and basic demographic variables of boreal caribou in three regions in northern Alberta, Canada. Contrary to expectations, caribou showed no change in home range sizes nor did they shift their home ranges in the years following fires, despite having up to 76% of individual home ranges burned. Within home ranges, caribou preferred stands >50 years old and avoided stands <50 years old, but the extent of home range burned did not affect habitat selection in the year after fire. Although fire does not seem to directly affect the spatial distribution of Alberta caribou, the generation of younger seral stages may affect how caribou distribute within their annual ranges. However, this did not appear to affect population demographics, as fire did not affect annual mortality or fecundity. Boreal caribou in Alberta may be resilient to the effects of fire owing to large home ranges.
Biodiversity genomics for species at risk: patterns of DNA sequence variation within and among complete mitochondrial genomes of three species of wolffish (Anarhichas spp.)
Authors: Johnstone K.A. , Marshall H.D. , Carr S.M.
Published: May 2007

The first marine fish species to be listed under the Canadian Species At Risk Act as Threatened with extinction are the spotted wolffish ( Anarhichas minor Olafsen, 1774) and the broadhead wolffish ( Anarhichas denticulatus Krøyer, 1844); a third species, the striped wolffish ( Anarhichas lupus L., 1758), is listed as a species of special concern. As part of the recovery plan for wolffish, we determined the complete mitochondrial DNA (mtDNA) genome sequences of all three species to identify the most variable gene regions for population analysis. Anarhichas genomes comprise either 16 519 or 16 520 base pairs (bp), among which there are 449 single nucleotide polymorphisms (SNPs). The most variable protein-coding loci are ND4, CYTB, and ND2, with 4.40, 4.22, and 4.19 SNPs / 100 bp, respectively. Comparisons of rates of synonymous and nonsynonymous nucleotide substitutions indicate no evidence of selection. The control region, characterized in many species as hypervariable, was less variable than 9 of 13 protein-coding loci (2.45 SNPs / 100 bp). Phylogenetic analysis shows that A. lupus and A. minor are more closely related to each other than either is to A. denticulatus. Amplification and sequence analysis of a contiguous block of 6392 bp that spans the ND4, ND5, ND6, and CYTB loci is an efficient strategy for evaluating patterns of intraspecific mtDNA variability.
Local- and landscape-level den selection of striped skunks on the Canadian prairies
Authors: Hwang Yeen Ten , Larivière Serge , Messier François
Published: May 2007

We examined the seasonal landscape and habitat use patterns of striped skunks ( Mephitis mephitis Schreber, 1776). We tracked 52 male and 72 female skunks from September 1999 to June 2003 in Saskatchewan, Canada. At the local level, den structures differed by sex and season. In autumn/winter, all skunks preferred buildings, whereas in spring/summer females selectively used underground burrows and rock piles for parturition and rearing of young, and males used aboveground retreats. Den sites were closer to crop fields, roads, water sources, and macrohabitat edges than random sites. At the landscape level, den sites were associated positively with weighted mean shape index of crop fields, mean patch size of water bodies, total edge of water bodies, and weighted mean fractal dimensions of grassland, woodland, and farmsteads, suggesting that wetland edges and habitat complexity are important in den selection by skunks. Compositional analysis revealed sex- and season-specific differences at the population level. Both sexes preferred grassland/pastures and farmstead habitats for establishing den sites. In autumn/winter, skunks preferred grassland/pastures for winter dens. However, in spring/summer skunks preferred farmsteads for resting sites. Our results suggest that skunks respond to landscape and habitat features surrounding den sites, and not just specific den or local habitat characteristics.