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Physiological and Biochemical Zoology: PBZ

Layla Hiramatsu, Theodore Garland
Understanding evolution is a necessary component of undergraduate education in biology, and evolution is difficult to explain without studying the heritability of traits. However, in most classes, heritability is presented with only a handful of graphs showing typical morphological traits, for example, beak size in finches and height in humans. The active-inquiry exercise outlined in the following pages allows instructors to engage students in this formerly dry subject by bringing their own data as the basis for estimates of heritability...
November 2016: Physiological and Biochemical Zoology: PBZ
Karine Salin, Sonya K Auer, Agata M Rudolf, Graeme J Anderson, Colin Selman, Neil B Metcalfe
Standard metabolic rate (SMR) and maximum metabolic rate (MMR) typically vary two- or threefold among conspecifics, with both traits assumed to significantly impact fitness. However, the underlying mechanisms that determine such intraspecific variation are not well understood. We examined the influence of mitochondrial properties on intraspecific variation in SMR and MMR and hypothesized that if SMR supports the cost of maintaining the metabolic machinery required for MMR, then the mitochondrial properties underlying these traits should be shared...
November 2016: Physiological and Biochemical Zoology: PBZ
Pauline Vuarin, Pierre-Yves Henry, Martine Perret, Fabien Pifferi
Polyunsaturated fatty acids (PUFAs) are involved in a variety of physiological mechanisms, including heterothermy preparation and expression. However, the effects of the two major classes of PUFAs, n-6 and n-3, can differ substantially. While n-6 PUFAs enhance torpor expression, n-3 PUFAs reduce the ability to decrease body temperature. This negative impact of n-3 PUFAs has been revealed in temperate hibernators only. Yet because tropical heterotherms generally experience higher ambient temperature and exhibit higher minimum body temperature during heterothermy, they may not be affected as much by PUFAs as their temperate counterparts...
November 2016: Physiological and Biochemical Zoology: PBZ
Andrea Novelletto, Letizia Testa, Federico Iacovelli, Paola Blasi, Luisa Garofalo, Toni Mingozzi, Mattia Falconi
We sequenced coding portions (1.6 kb) of the mtDNA in 170 loggerhead (Caretta caretta) turtles sampled in the central Mediterranean. The sequences spanned the entire ND1 and ND3 genes, the tRNAGly and tRNAArg, plus the 3' and 5' termini of COXIII and ND4L genes, respectively. Based on our sequencing results and published complete mitogenomes, we constructed a maximum parsimony phylogeny of C. caretta matrilines that sheds new light on the evolutionary relationships within the collection of lineages found in the Mediterranean and so far recognized by D-loop haplotypes only...
November 2016: Physiological and Biochemical Zoology: PBZ
Jesús M Avilés, Deseada Parejo
In altricial birds, sex differentiation can start early in the ontogeny in the form of color, physiology, and/or growth and may potentially result in sex-specific condition dependence of traits mediating parent-offspring communication. Carotenoids have long been hypothesized to modulate the expression of gape coloration, but their sex-specific role enforcing honesty of gape coloration remains poorly studied. In a within-nest design, we provided carotenoid supplementation to nestlings of the Eurasian roller (Coracias garrulus) and measured the response in circulating carotenoids, coloration of the gape, cutaneous immune responsiveness to phytohemagglutinin, and growth while accounting for the sex of nestlings...
November 2016: Physiological and Biochemical Zoology: PBZ
Neal Ingraham Callaghan, Louise Tunnah, Suzanne Currie, Tyson James MacCormack
In rainbow trout, warmer temperatures increase metabolic rate, which can be energetically stressful. Diel fluctuations in water temperatures are common in rivers, raising the question of whether fish experience metabolic preconditioning with repeated heat stress. In this study, rainbow trout (Oncorhynchus mykiss Walbaum, 1792) were subjected to three temperature treatments consisting of either a constant exposure to 16°C, a single exposure to 24°C, or three cycles between 16° and 24°C. Metabolic responses were investigated, including patterns of regulation of adenosine monophosphate-activated protein kinase and its substrates, key metabolic enzymes, and several relevant metabolites...
November 2016: Physiological and Biochemical Zoology: PBZ
Pablo Burraco, Ivan Gomez-Mestre
Natural and anthropogenic disturbances cause profound alterations in organisms, inducing physiological adjustments to avoid, reduce, or remedy the impact of disturbances. In vertebrates, the stress response is regulated via neuroendocrine pathways, including the hypothalamic-pituitary-interrenal axis that regulates the secretion of glucocorticoids. Glucocorticoids have cascading effects on multiple physiological pathways, affecting the metabolic rate, reactive oxygen species production, or immune system. Determining the extent to which natural and anthropogenic environmental factors induce stress responses in vertebrates is of great importance in ecology and conservation biology...
November 2016: Physiological and Biochemical Zoology: PBZ
Jeffrey M Goessling, Craig Guyer, Mary T Mendonça
Studies have suggested a role for natural seasonal change to drive patterns of disease, especially within ectothermic vertebrates. In light of recent climate change, it is important to understand baseline disease resistance in a seasonal context to further understand the role that changes in seasonal weather patterns may have in increasing disease frequency. Herein we found support for the seasonal acclimation hypothesis in Gopherus polyphemus (gopher tortoise), which indicated that natural seasonal variation causes differences in baseline immune function across seasonal acclimation states...
November 2016: Physiological and Biochemical Zoology: PBZ
Jessica L Malisch, Karen deWolski, Thomas H Meek, Wendy Acosta, Kevin M Middleton, Ondi L Crino, Theodore Garland
In vertebrates, acute stressors-although short in duration-can influence physiology and behavior over a longer time course, which might have important ramifications under natural conditions. In laboratory rats, for example, acute stress has been shown to increase anxiogenic behaviors for days after a stressor. In this study, we quantified voluntary wheel-running behavior for 22 h following a restraint stress and glucocorticoid levels 24 h postrestraint. We utilized mice from four replicate lines that have been selectively bred for high voluntary wheel-running activity (HR mice) for 60 generations and their nonselected control (C) lines to examine potential interactions between exercise propensity and sensitivity to stress...
November 2016: Physiological and Biochemical Zoology: PBZ
Brent Sinclair
No abstract text is available yet for this article.
September 2016: Physiological and Biochemical Zoology: PBZ
Barbara Tschirren, Ann-Kathrin Ziegler, Cindy I Canale, Monika Okuliarová, Michal Zeman, Mathieu Giraudeau
Yolk androgens of maternal origin are important mediators of prenatal maternal effects. Although in many species short-term benefits of exposure to high yolk androgen concentrations for the offspring have been observed, females differ substantially in the amount of androgens they transfer to their eggs. It suggests that costs for the offspring or the mother constrain the evolution of maternal hormone transfer. However, to date, the nature of these costs remains poorly understood. Unlike most previous work that focused on potential costs for the offspring, we here investigated whether high yolk testosterone transfer is associated with metabolic costs (i...
September 2016: Physiological and Biochemical Zoology: PBZ
Rémy Simide, Frédéric Angelier, Sandrine Gaillard, Antoine Stier
Telomeres shorten at each cell division due to the end-replication problem but also in response to oxidative stress. Consequently, telomeres shorten with age in many endotherms, and this shortening is accelerated under stressful environmental conditions. Data in ectotherm vertebrates remain scarce so far, so our goal was to review existing data for fish and to test the influence of age and stress on telomere length in a very long-lived fish, the Siberian sturgeon (Acipenser baerii). Our review of the literature revealed age-related telomere shortening in approximately half of the published studies...
September 2016: Physiological and Biochemical Zoology: PBZ
Janek Urvik, Richard Meitern, Kalev Rattiste, Lauri Saks, Peeter Hõrak, Tuul Sepp
Age-related declines in life-history traits have been widely observed in free-living animals. Several theories link senescence to oxidative stress. The aim of this study was to measure several widely used markers of oxidative and nutritional state in a long-lived seabird, the common gull (Larus canus), in order to assess the suitability of these markers for describing deterioration in physiological condition associated with chronological age and survival. Associations with longevity and individual consistency of these parameters over the years (repeatability) were also assessed...
September 2016: Physiological and Biochemical Zoology: PBZ
Rachael M Heuer, Kathleen M Munley, Nafis Narsinghani, Jessica A Wingar, Theresa Mackey, Martin Grosell
Most marine teleosts defend blood pH during high CO2 exposure by sustaining elevated levels of HCO3(-) in body fluids. In contrast to the gill, where measures are taken to achieve net base retention, elevated CO2 leads to base loss in the intestine of marine teleosts studied to date. This loss is thought to occur through transport pathways previously demonstrated to be involved with routine osmoregulation in marine teleosts. The main objective of this study was to characterize the intestinal transport physiology of the gulf toadfish (Opsanus beta) when exposed to varied levels of CO2: control, 5,000, 10,000, and 20,000 μatm CO2 (0...
September 2016: Physiological and Biochemical Zoology: PBZ
Alexa Fritzsche McKay, Vanessa O Ezenwa, Sonia Altizer
Organisms have a finite pool of resources to allocate toward multiple competing needs, such as development, reproduction, and enemy defense. Abundant resources can support investment in multiple traits simultaneously, but limited resources might promote trade-offs between fitness-related traits and immune defenses. We asked how food restriction at both larval and adult life stages of the monarch butterfly (Danaus plexippus) affected measures of immunity, fitness, and immune-fitness interactions. We experimentally infected a subset of monarchs with a specialist protozoan parasite to determine whether parasitism further affected these relationships and whether food restriction influenced the outcome of infection...
September 2016: Physiological and Biochemical Zoology: PBZ
Nicholas W Pilfold, Daryll Hedman, Ian Stirling, Andrew E Derocher, Nicholas J Lunn, Evan Richardson
Polar bears (Ursus maritimus) have adapted to an annual cyclic regime of feeding and fasting, which is extreme in seasonal sea ice regions of the Arctic. As a consequence of climate change, sea ice breakup has become earlier and the duration of the open-water period through which polar bears must rely on fat reserves has increased. To date, there is limited empirical data with which to evaluate the potential energetic capacity of polar bears to withstand longer fasts. We measured the incoming and outgoing mass of inactive polar bears (n = 142) that were temporarily detained by Manitoba Conservation and Water Stewardship during the open-water period near the town of Churchill, Manitoba, Canada, in 2009-2014...
September 2016: Physiological and Biochemical Zoology: PBZ
Alison H Doherty, Danielle M Roteliuk, Sara E Gookin, Ashley K McGrew, Carolyn J Broccardo, Keith W Condon, Jessica E Prenni, Samantha J Wojda, Gregory L Florant, Seth W Donahue
Periods of physical inactivity increase bone resorption and cause bone loss and increased fracture risk. However, hibernating bears, marmots, and woodchucks maintain bone structure and strength, despite being physically inactive for prolonged periods annually. We tested the hypothesis that bone turnover rates would decrease and bone structural and mechanical properties would be preserved in hibernating marmots (Marmota flaviventris). Femurs and tibias were collected from marmots during hibernation and in the summer following hibernation...
September 2016: Physiological and Biochemical Zoology: PBZ
Chris J Law, Colleen Young, Rita S Mehta
Sexual dimorphism attributed to niche divergence is often linked to differentiation between the sexes in both dietary resources and characters related to feeding and resource procurement. Although recent studies have indicated that southern sea otters (Enhydra lutris nereis) exhibit differences in dietary preferences as well as sexual dimorphism in skull size and shape, whether these intersexual differences translate to differentiation in feeding performances between the sexes remains to be investigated. To test the hypothesis that scaling patterns of bite force, a metric of feeding performance, differ between the sexes, we calculated theoretical bite forces for 55 naturally deceased male and female southern sea otters spanning the size ranges encountered over ontogeny...
September 2016: Physiological and Biochemical Zoology: PBZ
Don J Larson, Brian M Barnes
Ice nucleation across the skin of wood frogs (Lithobates sylvaticus) rapidly induces endogenous production of glucose, a cryoprotectant necessary for freeze tolerance. In laboratory studies of freeze tolerance, wood frogs are cooled slowly, often at -0.05°C h(-1), to facilitate high cryoprotectant production and survival. Under natural conditions in Alaska, however, wood frogs accumulate maximal tissue glucose concentrations while cooling at much faster rates, -0.35° to -1.6°C h(-1), and in addition undergo multiple successive freeze-thaw cycles before remaining frozen for the winter...
July 2016: Physiological and Biochemical Zoology: PBZ
A S Pollard, A A Pitsillides, S J Portugal
Avian embryos are a commonly used model system for developmental studies, but monitoring of physiological parameters such as heart rate (HR) and movement in ovo poses a challenge to researchers. These are also increasingly common research objectives for ecological and embryo behavior studies in oviparous species. We therefore explored the validity of a new digital egg-monitoring system for the noninvasive monitoring of these parameters. We tested the relationship between frequency-of-movement values gathered by digital monitoring and those gathered by the current standard method, which is comparatively invasive and requires egg windowing, and demonstrated that the digital monitoring method effectively distinguishes individual movements but cannot reliably monitor HR in actively motile embryos...
July 2016: Physiological and Biochemical Zoology: PBZ
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