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Articles 1 - 8 of 8

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

A Phylogenetic Analysis Of The Correlates Of Sleep In Birds, Timothy Roth, John Lesku, Charles Amlaner, Steven Lima Nov 2006

A Phylogenetic Analysis Of The Correlates Of Sleep In Birds, Timothy Roth, John Lesku, Charles Amlaner, Steven Lima

Charles J. Amlaner

Quantitative comparative studies of sleep have focused exclusively on mammals. Such studies have repeatedly found strong relationships between the time spent in various sleep states and constitutive variables related to morphology, physiology, and life history. These studies influenced the development of several prominent hypotheses for the functions of sleep, but the applicability of these patterns and hypotheses to non-mammalian taxa is unclear. Here, we present the first quantitative analysis of sleep in a non-mammalian taxon (birds), focusing on the daily amount of time spent in slow-wave sleep (SWS) and rapid-eye movement (REM) sleep as determined by electrophysiological methods. We examined ...


A Phylogenetic Analysis Of Sleep Architecture In Mammals: The Integration Of Anatomy, Physiology, And Ecology, John Lesku, Timothy Roth, Charles Amlaner, Steven Lima Sep 2006

A Phylogenetic Analysis Of Sleep Architecture In Mammals: The Integration Of Anatomy, Physiology, And Ecology, John Lesku, Timothy Roth, Charles Amlaner, Steven Lima

Charles J. Amlaner

Among mammalian species, the time spent in the two main "architectural" states of sleep-slow-wave sleep (SWS) and rapid-eye-movement (REM) sleep-varies greatly. Previous comparative studies of sleep architecture found that larger mammals, those with bigger brains, and those with higher absolute basal metabolic rates (BMR) tended to engage in less SWS and REM sleep. Species experiencing a greater risk of predation also exhibited less SWS and REM sleep. In all cases, however, these studies lacked a formal phylogenetic and theoretical framework and used mainly correlational analyses. Using independent contrasts and an updated data set, we extended existing approaches with path analysis ...


Chemical Evidence For Dietary Toxin Sequestration In The Asian Snake Rhabdophis Tigrinus, Deborah A. Hutchinson Jul 2006

Chemical Evidence For Dietary Toxin Sequestration In The Asian Snake Rhabdophis Tigrinus, Deborah A. Hutchinson

Biological Sciences Theses & Dissertations

Rhabdophis tigrinus (Colubridae: Natricinae) is an oviparous, bufophagous (toad-eating) snake from eastern Asia that possesses defensive integumentary glands on the neck known as nuchal glands. These glands are used in antipredator displays and typically contain bufadienolide toxins. Whereas toads are known to synthesize bufadienolide steroids from cholesterol precursors, we found that chemically undefended R. tigrinus must sequester bufadienolides from ingested toads in order to exhibit these compounds in their nuchal glands. Chemically defended females are capable of provisioning their embryos with these toxins so their unfed hatchlings possess defensive bufadienolides prior to consuming toads themselves. All of the hatchling R ...


Screening For Antibiotic, Antifungal And Antitumoral Compounds In Natural Products Extracted From Freshwater Sponges, Danielle Daehnke Apr 2006

Screening For Antibiotic, Antifungal And Antitumoral Compounds In Natural Products Extracted From Freshwater Sponges, Danielle Daehnke

Life and Environmental Sciences Undergraduate Theses

The secondary metabolites of marine sponges include many bioactive products (e.g., ara-C) that have found uses in the health field. Even though freshwater sponges share many characteristics with their marine cousins, little is known about their secondary metabolites. This study looks at the effects of the secondary metabolites extracted from three freshwater sponge species on the survival of bacteria, fungi and brine shrimp. It found that none of the extracts were toxic to the bacteria or fungi. Preliminary results did, however, show that all three species tested were active against the brine shrimp. This study suggests that the secondary ...


Asynchronous Eye Closure As An Anti-Predator Behavior In The Western Fence Lizard (Sceloporus Occidentalis), Christian Mathews, John Lesku, Stephen Lima, Charles Amlaner Feb 2006

Asynchronous Eye Closure As An Anti-Predator Behavior In The Western Fence Lizard (Sceloporus Occidentalis), Christian Mathews, John Lesku, Stephen Lima, Charles Amlaner

Charles J. Amlaner

Asynchronous eye closure (ASEC), one eye open while the other is closed, is a behavior observed in birds, some aquatic mammals, and reptiles. In birds and aquatic mammals, ASEC is associated with unihemispheric sleep wherein the cerebral hemisphere contralateral to (i.e. neurologically connected to) the closed eye sleeps while the other cerebral hemisphere remains awake with its associated eye open and functional. Evidence from birds suggests that ASEC is an important anti-predator adaptation to mediate the trade-off between the need to remain vigilant and the need to sleep. However, the anti-predator correlates of ASEC remain largely unstudied in other ...


Redesigning Beef Cattle To Have A More Healthful Fatty Acid Composition, Shu Zhang, Travis J. Knight, Richard G. Tait Jr., Allen H. Trenkle, Doyle E. Wilson, Gene H. Rouse, Daryl R. Strohbehn, James M. Reecy, Donald C. Beitz, Jennifer A. Minick Jan 2006

Redesigning Beef Cattle To Have A More Healthful Fatty Acid Composition, Shu Zhang, Travis J. Knight, Richard G. Tait Jr., Allen H. Trenkle, Doyle E. Wilson, Gene H. Rouse, Daryl R. Strohbehn, James M. Reecy, Donald C. Beitz, Jennifer A. Minick

Iowa State Research Farm Progress Reports

We propose to improve the fatty acid composition of beef by capitalizing on the natural genetic differences among animals. It is our thought that improvements in the healthfulness of the fatty acid composition of beef can be made while maintaining other positive attributes. Stearoyl-CoA desaturase is responsible for the conversion of 16:0 and 18:0 to 16:1 and 18:1, respectively, the two major monounsaturated fatty acids of bovine lipids.


Differential Effects Of Sodium And Magnesium Sulfate On Water Consumption By Beef Cattle, A. S. Grout, D. M. Veira, D. M. Weary, M. A. G. Von Keyserlingk, D. Fraser Jan 2006

Differential Effects Of Sodium And Magnesium Sulfate On Water Consumption By Beef Cattle, A. S. Grout, D. M. Veira, D. M. Weary, M. A. G. Von Keyserlingk, D. Fraser

Biochemistry Collection

The existing guidelines for maximum sulfate (SO4) in cattle drinking water are based on Na2SO4, although many water sources contain greater concentrations of MgSO4. Two experiments compared the effect of different SO4 salts on water consumption and fecal DM of cattle. In Exp. 1, 8 yearling heifers (initial BW = 345 ± 8 kg; mean ± SD) were watered twice daily with tapwater or water containing Na2SO4 or MgSO4 at target levels of 1,500, 3,000, or 4,500 mg of SO4/L for 2-d treatment periods separated by 2 d of access ...


The Evolution Of Sleep: A Phylogenetic Approach, John Lesku, Niels Rattenborg, Charles Amlaner Dec 2005

The Evolution Of Sleep: A Phylogenetic Approach, John Lesku, Niels Rattenborg, Charles Amlaner

Charles J. Amlaner

No abstract provided.