1,257 research outputs found

    The Gray Wolves (Canis lupus) of British Columbia’s Coastal Rainforests

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    The mainland coast of British Columbia (BC) is a remote area that is comparatively free from human-caused disturbance. However, concerns about current and anticipated increases in industrial forestry activity have prompted conservation biologists to investigate the biota in this understudied region. We were commissioned by the Raincoast Conservation Society to study coastal wolves so that information could be incorporated into ongoing conservation planning and education efforts. The summer of 2000 marked the pilot season of a multi-year research project. Our team spent more than 240 person days in the field during the summer and fall seasons. We surveyed 18 mainland watersheds and 21 islands in an area greater than 29,000-km2 (land and sea). We examined scats to describe wolf diet, collected genetic material, and noted other natural history observations. We also conducted an extensive review of scientific literature and made estimates of population size and human-caused mortality

    What Enables Size-Selective Trophy Hunting of Wildlife?

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    Although rarely considered predators, wildlife hunters can function as important ecological and evolutionary agents. In part, their influence relates to targeting of large reproductive adults within prey populations. Despite known impacts of sizeselective harvests, however, we know little about what enables hunters to kill these older, rarer, and presumably more wary individuals. In other mammalian predators, predatory performance varies with knowledge and physical condition, which accumulates and declines, respectively, with age. Moreover, some species evolved camouflage as a physical trait to aid in predatory performance. In this work, we tested whether knowledge-based faculty (use of a hunting guide with accumulated experience in specific areas), physical traits (relative body mass [RBM] and camouflage clothing), and age can predict predatory performance. We measured performance as do many hunters: size of killed cervid prey, using the number of antler tines as a proxy. Examining ,4300 online photographs of hunters posing with carcasses, we found that only the presence of guides increased the odds of killing larger prey. Accounting for this effect, modest evidence suggested that unguided hunters presumably handicapped with the highest RBM actually had greater odds of killing large prey. There was no association with hunter age, perhaps because of our coarse measure (presence of grey hair) and the performance tradeoffs between knowledge accumulation and physical deterioration with age. Despite its prevalence among sampled hunters (80%), camouflage had no influence on size of killed prey. Should these patterns be representative of other areas and prey, and our interpretations correct, evolutionarily-enlightened harvest management might benefit from regulatory scrutiny on guided hunting. More broadly, we suggest that by being nutritionally and demographically de-coupled from prey and aided by efficient killing technology and road access, wildlife hunters in the developed world might have overcome many of the physical, but not knowledge-based, challenges of hunting

    A novel selective 11b-hydroxysteroid dehydrogenase type 1 inhibitor prevents human adipogenesis.

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    Glucocorticoid excess increases fat mass, preferentially within omental depots; yet circulating cortisol concentrations are normal in most patients with metabolic syndrome (MS). At a pre-receptor level, 11b-hydroxysteroid dehydrogenase type 1 (11b-HSD1) activates cortisol from cortisone locally within adipose tissue, and inhibition of 11b-HSD1 in liver and adipose tissue has been proposed as a novel therapy to treat MS by reducing hepatic glucose output and adiposity. Using a transformed human subcutaneous preadipocyte cell line (Chub-S7) and human primary preadipocytes, we have defined the role of glucocorticoids and 11b-HSD1 in regulating adipose tissue differentiation. Human cells were differentiated with 1.0 mM cortisol (F), or cortisone (E) with or without 100 nM of a highly selective 11b-HSD1 inhibitor PF-877423. 11b-HSD1 mRNA expression increased across adipocyte differentiation (P!0.001, nZ4), which was paralleled by an increase in 11b-HSD1 oxo-reductase activity (from nil on day 0 to 5.9G1.9 pmol/mg per h on day 16,P!0.01, nZ7). Cortisone enhanced adipocyte differentiation; fatty acid-binding protein 4 expression increased 312-fold (P!0.001) and glycerol-3-phosphate dehydrogenase 47-fold (P!0.001) versus controls. This was abolished by co-incubation with PF-877423. In addition, cellular lipid content decreased significantly. These findings were confirmed in the primary cultures of human subcutaneous preadipocytes. The increase in 11b-HSD1 mRNA expression and activity is essential for the induction of human adipogenesis. Blocking adipogenesis with a novel and specific 11b-HSD1 inhibitor may represent a novel approach to treat obesity in patients with MS

    Online Hunting Forums Identify Achievement as Prominent Among Multiple Satisfactions

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    Understanding hunter satisfactions can lead to improved wildlife management policy and practice. Whereas previous work has suggested that hunters often seek multiple satisfactions (achievement, affiliation, appreciation), little is known about how satisfactions might vary with target species. Additionally, past research has mostly gathered data using interviews and surveys, which might limit scope as well as introduce strategic bias for potentially provocative subjects such as hunting. To address these gaps, we analyzed data from online hunting forums, which provide an open-access source of peer-to-peer discussion that is geographically and taxonomically broad. We used directed qualitative content analysis to analyze hunting narratives for satisfactions by coding 2,864 phrases across 455 hunting “stories,” and compared patterns of dominant (most frequent) and multiple satisfactions between target species type (ungulates and carnivores) using forums from 3 regions: British Columbia, Canada; Texas, USA; and North America-wide. We found that achievement was the dominant satisfaction in 81% of ungulate and 86% of carnivore stories. Appreciation was nearly absent as a dominant satisfaction in carnivore stories. We found that 62% of ungulate and 53% of carnivore stories had multiple satisfactions present, indicating that appreciation and affiliation play important secondary satisfaction roles even when achievement is dominant. If these data are broadly representative of hunters on a larger scale, management policy instruments that ignore achievement may not evoke change in hunter behavior, particularly involving carnivore target species. Despite limitations associated with online forums (e.g., nonrepresentative of all hunters), they provide a new and valuable resource for wildlife management research

    Offspring subcutaneous adipose markers are sensitive to the timing of maternal gestational weight gain

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    peer-reviewedBackground Excessive maternal weight gain during pregnancy impacts on offspring health. This study focused on the timing of maternal gestational weight gain, using a porcine model with mothers of normal pre-pregnancy weight. Methods Trial design ensured the trajectory of maternal gestational weight gain differed across treatments in early, mid and late gestation. Diet composition did not differ. On day 25 gestation, sows were assigned to one of five treatments: Control sows received a standard gestation diet of 2.3 kg/day (30 MJ DE/day) from early to late gestation (day 25–110 gestation). E sows received 4.6 kg food/day in early gestation (day 25–50 gestation). M sows doubled their food intake in mid gestation (day 50–80 gestation). EM sows doubled their food intake during both early and mid gestation (day 25–80 gestation). L sows consumed 3.5 kg food/day in late gestation (day 80–110 gestation). Offspring body weight and food intake levels were measured from birth to adolescence. Markers of lipid metabolism, hypertrophy and inflammation were investigated in subcutaneous adipose tissue of adolescent offspring. Results The trajectory of gestational weight gain differed across treatments. However total gestational weight gain did not differ except for EM sows who were the heaviest and fattest mothers at parturition. Offspring birth weight did not differ across treatments. Subcutaneous adipose tissue from EM offspring differed significantly from controls, with elevated mRNA levels of lipogenic (CD36, ACACB and LPL), nutrient transporters (FABP4 and GLUT4), lipolysis (HSL and ATGL), adipocyte size (MEST) and inflammation (PAI-1) indicators. The subcutaneous adipose depot from L offspring exhibited elevated levels of CD36, ACACB, LPL, GLUT4 and FABP4 mRNA transcripts compared to control offspring. Conclusions Increasing gestational weight gain in early gestation had the greatest impact on offspring postnatal growth rate. Increasing maternal food allowance in late gestation appeared to shift the offspring adipocyte focus towards accumulation of fat. Mothers who gained the most weight during gestation (EM mothers) gave birth to offspring whose subcutaneous adipose tissue, at adolescence, appeared hyperactive compared to controls. This study concluded that mothers, who gained more than the recommended weight gain in mid and late gestation, put their offspring adipose tissue at risk of dysfunction.This research was funded by Teagasc, under the National Development Plan. LBMcN was in receipt of a Teagasc Walsh Fellowship. Nestle hosted LG on a sabbatical and funded the RT-PCR cost

    Why Men Trophy Hunt

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    The killing of Cecil the lion (Panthera leo) ignited enduring and increasingly global discussion about trophy hunting. Yet, policy debate about its benefits and costs focuses only on the hunted species and biodiversity, not the unique behaviour of hunters. Some contemporary recreational hunters from the developed world behave curiously, commonly targeting ‘trophies’: individuals within populations with large body or ornament size, as well as rare and/or inedible species, like carnivores. Although contemporary hunters have been classified according to implied motivation (i.e. for meat, recreation, trophy or population control, as well the ‘multiple satisfactions’ they seek while hunting (affiliation, appreciation, achievement; an evolutionary explanation of the motivation underlying trophy hunting (and big-game fishing) has never been pursued. Too costly (difficult, dangerous) a behaviour to be common among other vertebrate predators, we postulate that trophy hunting is in fact motivated by the costs hunters accept. We build on empirical and theoretical contributions from evolutionary anthropology to hypothesize that signalling these costs to others is key to understanding, and perhaps influencing, this otherwise perplexing activity

    Etablierung und Charakterisierung einer Cytochrom P450 Monooxygenase fĂŒr die Bioelektrokatalyse in einem dreidimensionalen CNT-Solgel Elektrodensystem

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    Die Motivation dieser durch das BMBF finanzierten ElektroZym Projekts ist die Überwindung der Limitation einer geringen spezifischen Produktleistung der bisher etablierten elektrochemisch getriebenen Cytochrom P450 Monooxygenase (CYP) Applikationen. Diese Applikationen wurden als Alternative zur meist unselektiven chemischen Metall-katalysierten Hydroxylierung entwickelt und stellen unterschiedliche hydroxlierte Produkte zur VerfĂŒgung. Dabei sind vor allem hydroxylierte FettsĂ€uren (OHFA) von Bedeutung, welche als Bausteine (building blocks) zur Synthese von z.B. Geruchs und Geschmackstoffen verwendet werden. Momentan sind diese OHFAs aufgrund der hohen Herstellungskosten nicht kommerziell verfĂŒgbar. Das Ziel des Projekts ist die Immobilisierung eines CYP Enzyms in einer dreidimensionalen, auf einer Solgel Matrix basierenden Elektrode. Die kovalente Immobilisierung von CYP Enzymen auf einer planaren ElektrodenoberflĂ€che fĂŒhrt im Idealfall zu einer einfachen OberflĂ€chenbedeckung (Monolayer) der Elektrode mit reduzierbarem Enzym. Die CYP Elektroden sind aufgrund der geringen OberflĂ€che in ihrer spezifischen Produktleistung stark limitiert. Daher wurde ein optimiertes CYP Enzym fĂŒr den Einsatz auf Kohlenstoffnanoröhren (CNT) basierten Elektroden etabliert. Als Enzym diente das von einer zusĂ€tzlichen Reduktase unabhĂ€ngige (autarke) CYP 102A1 aus Bacillus megaterium (P450 BM3). FĂŒr eine in situ AktivitĂ€tsbestimmung wurde das Enzym auf den Umsatz von Anilin zum elektroaktiven Aminophenol optimiert. Vier Enzymmutanten wurden zusĂ€tzlichen mit einer C-terminal lokalisierten und CNT-affinen Petidsequenz (CNT-tag) modifiziert. Diese werden im Folgenden als Modell Proteinvarianten bezeichnet. Diese Sequenz erlaubt die eigenstĂ€ndige und orientierte Anlagerung des Enzyms an der CNT OberflĂ€che und erleichtert die elektrochemische HĂ€meisenreduktion des Enzyms entscheidend. Die HĂ€meisenreduktion dieses P450 BM3 Konstruktes erlaubt die elektrochemisch getriebene enzymatische Hydroxylierung von Anilin. Diese elektrochemisch enzymatische Hydroxlierung erreichte 78 % der AktivitĂ€t, der Nicotinamid-abhĂ€ngigen Susbtratumsetzung. Das CNT-tag modifizierte Enzym wurde ebenfalls fĂŒr die erfolgreiche „proof-of-concept“ Etablierung einer dreidimensionalen CNT-Solgel Matrix Elektrode verwendet und die spezifische Produktleistung erreichte das dreifache Niveau einer verfgleichbaren planaren Elektrode

    Stable Isotope Analysis Of Summer Wolf Diet In Northwestern Montana

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    When distinct ?13C and ?15N values of potential prey are known, stable isotope analysis (SIA) of wolf (Canis lupus) hair can be used to estimate diet variability at the individual, pack, and regional levels. Our objectives were to estimate intra-population diet variability, and determine proportions of prey consumed by wolves. We collected guard hairs of 45 wolves from 12 packs in northwestern Montana and temporally matched scats from 4 of the same packs, summer 2008 and 2009. We used hierarchical Bayesian stable isotope mixing models to determine diet and scales of diet variation from ?13C and ?15N values of wolves, deer (Odocoileus spp.), elk (Cervus canadensis), moose (Alces alces), and other prey. We calculated percent biomass of prey consumed from scats, and used bootstrapped scat data, and Markov Chain Monte Carlo simulation data from stable isotopes to estimate confidence intervals of difference between results from each technique for the 4 packs with matched samples. Differences among packs explained most variability in diet based on stable isotopes, and moose was the most common prey item for 11 of 12 packs. From scat data, deer was the most common prey item for 3 of 4 packs, and estimates of moose consumed were significantly different from SIA estimates for the same 3 packs. The proportion of moose in wolf diet may have been overestimated by SIA because wolf-specific fractionation values were not available. Stable isotope analysis has the potential to efficiently provide useful management information, but experimentally derived fractionation values for wolves would likely improve the accuracy of estimates in future studies

    Signalling of Arabidopsis thaliana response to Pieris brassicae eggs shares similarities with PAMP-triggered immunity

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    Insect egg deposition activates plant defence, but very little is known about signalling events that control this response. In Arabidopsis thaliana, oviposition by Pieris brassicae triggers salicylic acid (SA) accumulation and induces the expression of defence genes. This is similar to the recognition of pathogen-associated molecular patterns (PAMPs), which are involved in PAMP-triggered immunity (PTI). Here, the involvement of known signalling components of PTI in response to oviposition was studied. Treatment with P. brassicae egg extract caused a rapid induction of early PAMP-responsive genes. In addition, expression of the defence gene PR-1 required EDS1, SID2, and, partially, NPR1, thus implicating the SA pathway downstream of egg recognition. PR-1 expression was triggered by a non-polar fraction of egg extract and by an oxidative burst modulated through the antagonistic action of EDS1 and NUDT7, but which did not depend on the NADPH oxidases RBOHD and RBOHF. Searching for receptors of egg-derived elicitors, a receptor-like kinase mutant, lecRK-I.8, was identified which shows a much reduced induction of PR-1 in response to egg extract treatment. These results demonstrate the importance of the SA pathway in response to egg-derived elicitor(s) and unravel intriguing similarities between the detection of insect eggs and PTI in Arabidopsi
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