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Articles 121 - 150 of 165

Full-Text Articles in Comparative and Evolutionary Physiology

The Physiological Stress Response Caused By Hypoxia And Reperfusion Injury In Striped Bass (Morone Saxatilis) And Nile Tilapia (Oreochromis Niloticus), Amanda C. Reynolds Jan 2015

The Physiological Stress Response Caused By Hypoxia And Reperfusion Injury In Striped Bass (Morone Saxatilis) And Nile Tilapia (Oreochromis Niloticus), Amanda C. Reynolds

College of Graduate Studies: Theses & Dissertations

Approximately five million people in the United States are affected by cardiovascular related diseases yearly contributing to 300,000 annual deaths, making CVD the leading cause of mortality worldwide. It has been suggested that apoptosis (programmed cell death) contributes to the pathogenesis of cardiovascular diseases. When blood flow is reduced or cut off from the heart, usually by a thrombus, this results in oxygen deprivation (hypoxia) to the cardiomyocytes (heart cells). In response to this hypoxic stress, cardiomyocytes will undergo apoptosis. Since many species of fish can survive levels of hypoxia that would be fatal to mammals, fish are an ideal …

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Physiological Variation Of Garry Oak (Quercus Garryana) Seedlings To Drought Stress, Matthew A. Merz Jan 2015

Physiological Variation Of Garry Oak (Quercus Garryana) Seedlings To Drought Stress, Matthew A. Merz

All Master's Theses

The purpose of this study was to determine physiological differences in drought response among Garry oak (Quercus garryana Douglas ex Hook. [Fagaceae]) seedlings that grow in distinct populations in Washington state, in order to aid in restoration efforts by informing growers of the potential differences between the acorn collection sites. Acorns from six Washington populations east of the Cascades, as well as one population from Whidbey Island, were collected and grown in containers under controlled conditions. The plants were assessed with and without moderate and severe drought stress induced by withholding water. The most extreme differences in photosynthetic characteristics …

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Ontogenetic Scaling Patterns And Functional Anatomy Of The Pelvic Limb Musculature In Emus (Dromaius Novaehollandiae), Luis P. Lamas, Russell P. Main, John R. Hutchinson Dec 2014

Ontogenetic Scaling Patterns And Functional Anatomy Of The Pelvic Limb Musculature In Emus (Dromaius Novaehollandiae), Luis P. Lamas, Russell P. Main, John R. Hutchinson

Department of Basic Medical Sciences Faculty Publications

Emus (Dromaius novaehollandiae) are exclusively terrestrial, bipedal and cursorial ratites with some similar biomechanical characteristics to humans. Their growth rates are impressive, as their body mass increases eighty-fold from hatching to adulthood whilst maintaining the same mode of locomotion throughout life. These ontogenetic characteristics stimulate biomechanical questions about the strategies that allow emus to cope with their rapid growth and locomotion, which can be partly addressed via scaling (allometric) analysis of morphology. In this study we have collected pelvic limb anatomical data (muscle architecture, tendon length, tendon mass and bone lengths) and calculated muscle physiological cross sectional area …

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Eggshell Calcium Regulates Calcium Transport Protein Expression In An Oviparous Snake, Hannah Frye May 2014

Eggshell Calcium Regulates Calcium Transport Protein Expression In An Oviparous Snake, Hannah Frye

Undergraduate Honors Theses

One hypothesis explaining the numerous independent evolutionary transitions from oviparity to viviparity among squamates (snakes and lizards) proposed that squamate embryonic development is independent of eggshell calcium. Recent research showed at least 25% of the calcium in hatchling oviparous squamates is extracted from the shell. Though not a direct test, these results are inconsistent with the hypothesis. To directly test the hypothesis, we removed eggshell calcium (through peeling) early in development of Pantherophis guttatus (corn snake) eggs. Survivorship to hatching did not differ between peeled and intact eggs. Yet hatchlings from peeled eggs were shorter (273.6 ± 3.4 vs. 261.0 …

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Distribution And Elimination Of 3-Trifluoromethyl-4-Nitrophenol (Tfm) By Sea Lamprey (Petromyzon Marinus) And Non-Target, Rainbow Trout (Oncorhynchus Mykiss) And Lake Sturgeon (Acipenser Fulvescens), Michael W. Le Clair Jan 2014

Distribution And Elimination Of 3-Trifluoromethyl-4-Nitrophenol (Tfm) By Sea Lamprey (Petromyzon Marinus) And Non-Target, Rainbow Trout (Oncorhynchus Mykiss) And Lake Sturgeon (Acipenser Fulvescens), Michael W. Le Clair

Theses and Dissertations (Comprehensive)

The pesticide, 3-trifluoromethyl-4-nitrophenol (TFM), has been highly successful in the control of sea lamprey (Petromyzon marinus) populations in the Great Lakes. Treatments with TFM involve applying it to streams, where it targets larval sea lamprey which live burrowed in the stream substrate. While the toxic mechanism of TFM has been elucidated, and its effects on sea lamprey described, its effects on non-target fish species such as rainbow trout (Oncorhynchus mykiss) and lake sturgeon (Acipenser fulvescens) are not as well understood. The present work demonstrated that rainbow trout show a great capacity to detoxify the lampricide using glucuronidation, when exposed to …

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Growth Of Tropical Dasyatid Rays Estimated Using A Multi-Analytical Approach, Owen R. O'Shea, Matias Braccini, Rory Mcauley, Conrad W. Speed, Mark G. Meekan Oct 2013

Growth Of Tropical Dasyatid Rays Estimated Using A Multi-Analytical Approach, Owen R. O'Shea, Matias Braccini, Rory Mcauley, Conrad W. Speed, Mark G. Meekan

Fisheries Research Articles

We studied the age and growth of four sympatric stingrays: reticulate whipray, Himanutra uarnak (n=19); blue mask, Neotrygon kuhlii (n=34); cowtail, Pastinachus atrus (n=32) and blue-spotted fantail, Taeniura lymma (n=40) rays at Ningaloo Reef, a fringing coral reef on the north-western coast of western Australia. Age estimates derived from band counts within sectioned vertebrae ranged between 1 and 27 years (H. uarnak, 1 - 25 yrs.; N. kuhlii, 1.5 - 13 yrs.; P. atrus, 1 - 27 yrs. and T. lymma, 1 -11 yrs.). Due to limitations of sample sizes, we combined several analytical methods …

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Colour And Odour Drive Fruit Selection And Seed Dispersal By Mouse Lemurs, Kim Valenta, Ryan J. Burke, Sarah A. Styler, Derek A. Jackson, Amanda D. Melin, Shawn M. Lehman Aug 2013

Colour And Odour Drive Fruit Selection And Seed Dispersal By Mouse Lemurs, Kim Valenta, Ryan J. Burke, Sarah A. Styler, Derek A. Jackson, Amanda D. Melin, Shawn M. Lehman

Dartmouth Scholarship

Animals and fruiting plants are involved in a complex set of interactions, with animals relying on fruiting trees as food resources, and fruiting trees relying on animals for seed dispersal. This interdependence shapes fruit signals such as colour and odour, to increase fruit detectability, and animal sensory systems, such as colour vision and olfaction to facilitate food identification and selection. Despite the ecological and evolutionary importance of plant-animal interactions for shaping animal sensory adaptations and plant characteristics, the details of the relationship are poorly understood. Here we examine the role of fruit chromaticity, luminance and odour on seed dispersal by …

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From Gibbons To Gymnasts: A Look At The Biomechanics And Neurophysiology Of Brachiation In Gibbons And Its Human Rediscovery, Emma Et Pennock May 2013

From Gibbons To Gymnasts: A Look At The Biomechanics And Neurophysiology Of Brachiation In Gibbons And Its Human Rediscovery, Emma Et Pennock

Student Works

This conference paper serves to examine the evolutionary linkages of a brachiating ancestor in humans, the biomechanical and neurophysiology of modern day brachiators, and the human rediscovery of this form of locomotion. Brachiation is arguably one of the most metabolically effective modes of travel by any organism and can be observed most meritoriously in Gibbons. The purpose of the research conducted for this paper was to encourage further exploration of the neurophysiological similarities and differences between humans and non-human primates. The hope is that in spurring more interest and research in this area, further possibilities for rehabilitating brain injury will …

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Variable Levels Of Atmospheric Oxygen Do Not Affect Microanatomy And Limb Bone Geometry In Alligator Mississippiensis, Susan Lee Lujan Jan 2013

Variable Levels Of Atmospheric Oxygen Do Not Affect Microanatomy And Limb Bone Geometry In Alligator Mississippiensis, Susan Lee Lujan

Theses Digitization Project

Striking changes in atmospheric oxygen levels have occured since the beginning of the Phanerozic 542 million years ago. Alligators belong to a clade of vertebrates with a long evolutionary history spanning much of this variability in atmospheric oxygen. An investigation into the effects of hypoxia and hyperoxia on skeletal growth and physiology in alligators may help to reconstruct the life history of archosaurs, explain patterns in the fossil record, and broaden our understanding of the processes underlying long term success of this clade.

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Postcranial Description And Reconstruction Of The Varanodontine Varanopid Aerosaurus Wellesi (Synapsida: Eupelycosauria), Valerie Ann Pelletier Jan 2013

Postcranial Description And Reconstruction Of The Varanodontine Varanopid Aerosaurus Wellesi (Synapsida: Eupelycosauria), Valerie Ann Pelletier

Theses Digitization Project

The postcranial skeleton of the varanopid synapsid aerosaurus wellesi is reconstructed based on several specimens including partly articulated material of an apparently fully adult specimen. Comparisons are made with other known varanopid taxa, reaffirming its position as a basal varanondontine.

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Euryhalinity In An Evolutionary Context, Eric T. Schultz, Stephen D. Mccormick Jan 2013

Euryhalinity In An Evolutionary Context, Eric T. Schultz, Stephen D. Mccormick

EEB Articles

This chapter focuses on the evolutionary importance and taxonomic distribution of euryhalinity. Euryhalinity refers to broad halotolerance and broad halohabitat distribution. Salinity exposure experiments have demonstrated that species vary tenfold in their range of tolerable salinity levels, primarily because of differences in upper limits. Halotolerance breadth varies with the species’ evolutionary history, as represented by its ordinal classification, and with the species’ halohabitat. Freshwater and seawater species tolerate brackish water; their empirically-determined fundamental haloniche is broader than their realized haloniche, as revealed by the halohabitats they occupy. With respect to halohabitat distribution, a minority of species (<10%) are euryhaline. Habitat-euryhalinity is prevalent among basal actinopterygian fishes, is largely absent from orders arising from intermediate nodes, and reappears in the most derived taxa. There is pronounced family-level variability in the tendency to be halohabitat-euryhaline, which may have arisen during a burst of diversification following the Cretaceous-Palaeogene extinction. Low prevalence notwithstanding, euryhaline species are potent sources of evolutionary diversity. Euryhalinity is regarded as a key innovation trait whose evolution enables exploitation of new adaptive zone, triggering cladogenesis. We review phylogenetically-informed studies that demonstrate freshwater species diversifying from euryhaline ancestors through processes such as landlocking. These studies indicate that some euryhaline taxa are particularly susceptible to changes in halohabitat and subsequent diversification, and some geographic regions have been hotspots for transitions to freshwater. Comparative studies on mechanisms among multiple taxa and at multiple levels of biological integration are needed to clarify evolutionary pathways to, and from, euryhalinity.

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Population Genetics And Ecology Of Regional Malaria Vectors In Amazonian Brazil, Sascha Naomi Mckeon Jan 2013

Population Genetics And Ecology Of Regional Malaria Vectors In Amazonian Brazil, Sascha Naomi Mckeon

Legacy Theses & Dissertations (2009 - 2024)

Species complexes are common among anopheline mosquitoes, but only some members of complexes are disease vectors. Research involving overall patterns of divergence, phylogenetic relationships and population structure is partly driven by the operational need to be able to reliably distinguish component taxa that may be involved in malaria transmission. Anopheles triannulatus, An. nuneztovari and An. albitarsis are broadly distributed species complexes that contain local and regionally important malaria vectors, whose genetic diversity has been largely overshadowed by studies involving An. darlingi, the principal vector of Central and South America. I have analyzed the ecological suitability of habitats and geographical ranges …

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Comparative Sugar Transport By Crustacean Hepatopancreas And Intestine, Ada Duka Jan 2013

Comparative Sugar Transport By Crustacean Hepatopancreas And Intestine, Ada Duka

UNF Graduate Theses and Dissertations

Glucose is transported in crustacean hepatopancreas and intestine by Na+-dependent co-transport, while Na+-dependent D-fructose influx has only been described for the hepatopancreas. It is still unclear if the two sugars are independently transported by two distinct cotransporter carrier systems. In this study lobster (Homarus americanus) hepatopancreas brush border membrane vesicles (BBMV) were used to characterize, in detail, the cation-dependency of both D-[3H] glucose and D-[3H] fructose influxes, while in vitro perfused intestines were employed to determine the nature of cation-dependent sugar transport in this organ. Over the sodium concentration range …

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Knockdown Of Vitellogenin By Rnai Increases Survivorship But Exhibits Similar Physiological Responses To Ovariectomy In Grasshoppers, Alicia G. Linquist Jan 2013

Knockdown Of Vitellogenin By Rnai Increases Survivorship But Exhibits Similar Physiological Responses To Ovariectomy In Grasshoppers, Alicia G. Linquist

UNF Graduate Theses and Dissertations

Reduced reproduction has been shown to increase lifespan in many animals, yet the mechanisms behind this trade-off are mostly unknown. A previous study has shown that in the lubber grasshopper, Romalea microptera, ovariectomized (OVX) individuals have a 30% increase in lifespan relative to controls (Sham). In a separate study, an increase in fat body mass and a halting of ovarian growth were seen upon reduction of vitellogenin transcript via RNAi (VgRNAi). These data suggest that VgRNAi increases lifespan through the trade-off between reproduction and longevity and animals with combined ovariectomy and VgRNAi, might show additive physiological responses. In this …

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Mechanisms Of Nitrogenous Waste Excretion During The Complex Life Cycle Of The Sea Lamprey (Petromyzon Marinus), James M. Neal Mr. Jan 2013

Mechanisms Of Nitrogenous Waste Excretion During The Complex Life Cycle Of The Sea Lamprey (Petromyzon Marinus), James M. Neal Mr.

Theses and Dissertations (Comprehensive)

Sea lampreys (Petromyzon marinus) are a phylogenetically ancient jawless fish, with a multi-staged life cycle characterized by a prolonged suspension-feeding larval stage, which is followed by metamorphosis into parasitic lampreys that feed on the protein-rich blood of fishes. The switch from a nutrient poor to protein-rich diet in the sea lamprey is associated with an increased capacity to deaminate excess amino acids and to excrete ammonia and urea following metamorphosis. The focus of this thesis was to determine if changes in nitrogenous waste transporter protein abundance facilitate ammonia and urea excretion during different stages of the sea lamprey …

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Phylogeny Of Panthera, Including P. Atrox, Based On Cranialmandibular Characters, Leigha M. King May 2012

Phylogeny Of Panthera, Including P. Atrox, Based On Cranialmandibular Characters, Leigha M. King

Electronic Theses and Dissertations

Over the past 20 years both morphological and molecular phylogenies have been proposed for extant and extinct members of the family Felidae. However, there remain several discrepancies, particularly within the genus Panthera and the position of Panthera atrox. Consequently, morphologic characters from the skull and dentary were analyzed within Panthera (including all extant and one extinct taxa) to gain a better understanding of pantherine phylogeny. Multiple specimens of each taxon were analyzed, including: P. leo, P. tigris, P. onca, P. pardus , Uncia uncia, and Neofelis nebulosa. Four outgroups were used; Crocuta crocuta, Metailurus ssp., Proailurus lemanensis …

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The Time-Course Of The Effects Of Growth Hormone During Zebrafish (Danio Rerio) Auditory Hair Cell Regeneration, Yajie Wang May 2012

The Time-Course Of The Effects Of Growth Hormone During Zebrafish (Danio Rerio) Auditory Hair Cell Regeneration, Yajie Wang

Masters Theses & Specialist Projects

Growth hormone (GH) was upregulated in the zebrafish inner ear following sound exposure in a previous study. To identify the specific role of GH in hair cell regeneration and the possible cellular mechanisms of this regeneration, groups of zebrafish were divided into baseline (no sound exposure, no injection), buffer-injected and GH-injected groups. Buffer- and GH-injected fish were exposed to a 150 Hz tone at a source level of 179 dB re 1 μPa root mean squared (RMS) for 36 h. Phalloidin-staining was used to assess the effects of GH on hair cell bundle density; BrdU-labeling was used to assess the …

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Salinity Preference Of Alaskan Threespine Stickleback: Test For Divergence In Halotaxis Between Ancestral And Landlocked Populations, David Fryxell, Eric T. Schultz Jan 2012

Salinity Preference Of Alaskan Threespine Stickleback: Test For Divergence In Halotaxis Between Ancestral And Landlocked Populations, David Fryxell, Eric T. Schultz

EEB Articles

Glacial retreat during the Pleistocene caused landlocking of anadromous Alaskan threespine stickleback, Gasterosteus aculeatus, furnishing a natural ‘experiment’ in osmoregulatory divergence. The objective of this study was to assess the effects of individual acclimation and population divergence on salinity preference. Full-sibling families of marine, anadromous, and freshwater-landlocked populations of stickleback were reared in common environments until 3 weeks post-hatch, then were split and acclimated to low or high salinity. At 6 to 8 weeks of age the six experimental groups were tested for salinity preference in a tank that offers fish a choice of compartments with different salinities arranged …

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Foraging And Roosting Behaviors Of Rafinesque's Big-Eared Bat (Corynorhinus Rafinesquii) At The Northern Edge Of The Species Range, Joseph S. Johnson Jan 2012

Foraging And Roosting Behaviors Of Rafinesque's Big-Eared Bat (Corynorhinus Rafinesquii) At The Northern Edge Of The Species Range, Joseph S. Johnson

Theses and Dissertations--Animal and Food Sciences

Bat populations in the eastern United States are currently declining at unprecedented rates as a result of habitat loss, commercial wind energy development, and white-nose syndrome. Effective conservation of these declining populations requires knowledge of several aspects of summer and winter ecology, including daytime habitat use (day-roost selection and social behaviors), nocturnal habitat use (foraging habitat selection, prey selection, and prey abundance), and winter hibernation (torpor) patterns. This dissertation addresses these questions for Rafinesque’s big-eared bat (Corynorhinus rafinesquii), a species of conservation concern in the southeastern United States. Kentucky represents the northern edge of the range of Rafinesque’s …

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Evolution Of Starvation Resistance In Drosophila Melanogaster: Measurement Of Direct And Correlated Responses To Artificial Selection, Tiffany E. Schwasinger-Schmidt, Stephen D. Kachman, Lawrence G. Harshman Jan 2012

Evolution Of Starvation Resistance In Drosophila Melanogaster: Measurement Of Direct And Correlated Responses To Artificial Selection, Tiffany E. Schwasinger-Schmidt, Stephen D. Kachman, Lawrence G. Harshman

Lawrence G. Harshman Publications

Laboratory selection for resistance to starvation has been conducted under relatively controlled conditions to investigate direct and correlated responses to artificial selection. With regard to starvation resistance, there are three physiological routes by which the trait can evolve: resource accumulation, energy conservation and starvation tolerance. A majority of energetic compounds and macromolecules including triglycerides, trehalose and other sugars, and soluble protein increased in abundance as a result of selection. Movement was additionally investigated with selected males moving less than control males and selected females exhibiting a similar response to selection. Results obtained from this study supported two of the possible …

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Systematics Of Protosteloid Amoebae, Lora Lindley Shadwick Dec 2011

Systematics Of Protosteloid Amoebae, Lora Lindley Shadwick

Graduate Theses and Dissertations

Because of their simple fruiting bodies consisting of one to a few spores atop a finely tapering stalk, protosteloid amoebae, previously called protostelids, were thought of as primitive members of the Eumycetozoa sensu Olive 1975. The studies presented here have precipitated a change in the way protosteloid amoebae are perceived in two ways: (1) by expanding their known habitat range and (2) by forcing us to think of them as amoebae that occasionally form fruiting bodies rather than as primitive fungus-like organisms. Prior to this work protosteloid amoebae were thought of as terrestrial organisms. Collection of substrates from aquatic habitats …

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The Relationship Between 11-Ketotestosterone, Cortisol, And Testosterone And Condition Index For Poecilia Reticulata, Shelly Gupta, Brandy G. Kalbach Mar 2011

The Relationship Between 11-Ketotestosterone, Cortisol, And Testosterone And Condition Index For Poecilia Reticulata, Shelly Gupta, Brandy G. Kalbach

Biological Sciences

The guppy, Poecilia reticulata, is a common study organism for behavioral and other ecological experiments (Houde, 1997).  As far as we know, no previous data have been compiled regarding hormones and condition index of guppies.  In this experiment we examined the relationship between circulating levels of three hormones (testosterone, 11-ketotestosterone and cortisol) and condition index in males and also made comparisons among the hormone levels, for three guppy sites from the northern range of Trinidad – Aripo River, Marianne River and Small Crayfish River.  Hormone samples were obtained using non-invasive water borne techniques and quantified by our collaborator.  The condition …

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Comparative Morphometrics Of The Sacral Vertebra In Aneides (Caudata: Plethodontidae)., Lisa Nicole Schaaf May 2010

Comparative Morphometrics Of The Sacral Vertebra In Aneides (Caudata: Plethodontidae)., Lisa Nicole Schaaf

Electronic Theses and Dissertations

The genus Aneides (Caudata: Plethodontidae) is an arboreal salamander with a prehensile tail and a distribution that spans North America. It is hypothesized that adaptations for arboreality will be visible in the osteology of the sacral vertebra either by qualitative analysis or linear and morphometric analysis in comparison with other plethodontid salamanders. This study demonstrates that while qualitative and quantitative analyses are successful at making genus-level distinctions between taxa, identification to lower taxonomic levels remains inconclusive. Linear morphometrics and dorsal Procrustes landmarks were the most successful metrics to identify known taxa. Two unidentified fossil salamander sacral vertebrae from Oregon Caves …

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The Complexity And Origins Of The Human Eye: A Brief Study On The Anatomy, Physiology, And Origin Of The Eye, Evan T. Sebastian Apr 2010

The Complexity And Origins Of The Human Eye: A Brief Study On The Anatomy, Physiology, And Origin Of The Eye, Evan T. Sebastian

Senior Honors Theses

The human eye has been the cause of much controversy in regards to its complexity and how the human eye came to be. Through following and discussing the anatomical and physiological functions of the eye, a better understanding of the argument of origins can be seen. The anatomy of the human eye and its many functions are clearly seen, through its complexity. When observing the intricacy of vision and all of the different aspects and connections, it does seem that the human eye is a miracle, no matter its origins. Major biological functions and processes occurring in the retina show …

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Interspecific Variation In Palatability Suggests Cospecialization Of Antipredator Defenses In Sea Hares, Kimberly K. Takagi, Nadia N. Ono, William G. Wright Jan 2010

Interspecific Variation In Palatability Suggests Cospecialization Of Antipredator Defenses In Sea Hares, Kimberly K. Takagi, Nadia N. Ono, William G. Wright

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Prey species often deploy different kinds of antipredator defenses, which can interact with each other in ways that are not yet completely understood. Much research into these interactions has utilized gastropod mollusks, usually focusing (in part) on the protective utility of the gastropod shell. This makes the evolutionary reduction of the shell in the opisthobranch gastropods (marine slugs) particularly interesting. This loss of protective function of the shell is associated with the evolution of alternative defenses. Particularly well studied are chemical defenses, especially those using secondary metabolites derived from food resources. As a first step toward understanding interspecific variation in …

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The Differential Roles Of D-Pax2 Variants In Regulating Drosophila Eye And Bristle Development, Colin J. O’Shea Jan 2010

The Differential Roles Of D-Pax2 Variants In Regulating Drosophila Eye And Bristle Development, Colin J. O’Shea

Honors Theses

The ability to appropriately interact with the environment is crucial to an organism’s survival. The establishment of functional sensory systems, such as the bristles and eyes in Drosophila, is a critical event during the development of the organism. The transcription factor D Pax2 is involved in the differentiation of the shaft and glial cells in the developing bristle (Kavaler et al., Dev, 126:2261-2272, 1999) and of the cone and primary pigment cells in the developing eye (Fu and Noll, Genes Dev, 11:389-405, 1997). How D-Pax2 contributes to distinct differentiative pathways in different cell types is not known. Recent work by …

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The Relationship Between Plasma Steroid Hormone Concentrations And The Reproductive Cycle Of The Northern Pacific Rattlesnake, Crotalus Oreganus, Craig Michael Lind Jun 2009

The Relationship Between Plasma Steroid Hormone Concentrations And The Reproductive Cycle Of The Northern Pacific Rattlesnake, Crotalus Oreganus, Craig Michael Lind

Master's Theses

To gain a better understanding of the role of steroid hormones in vertebrate reproduction, we quantified steroid hormone concentrations in a free ranging population of the Northern Pacific rattlesnake, Crotalus oreganus. Plasma steroid hormone concentrations were quantified for both male and female snakes throughout the active season (Mar-Oct). We measured testosterone (T), 5α-dihydrotestosterone (DHT), and corticosterone (B) concentrations in male and female snakes. 17β-estradiol (E2) and progesterone (P) were measured in females only. We also observed breeding behaviors (e.g. consortship, courtship, and copulation) in the field and measured testis and follicle size in male and female snakes from museum collections. …

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Mice Deficient In The Serine/Threonine Protein Kinase Vrk1 Are Infertile Due To A Progressive Loss Of Spermatogonia, Matthew S. Wiebe, R. Jeremy Nichols, Tyler P. Molitor, Jill K. Lindgren, Paula Traktman Jan 2009

Mice Deficient In The Serine/Threonine Protein Kinase Vrk1 Are Infertile Due To A Progressive Loss Of Spermatogonia, Matthew S. Wiebe, R. Jeremy Nichols, Tyler P. Molitor, Jill K. Lindgren, Paula Traktman

Nebraska Center for Virology: Faculty Publications

The VRK1 protein kinase has been implicated as a proproliferative factor. Genetic analyses of mutant alleles of the Drosophila and Caenorhabditis elegans VRK1 homologs have revealed phenotypes ranging from embryonic lethality to mitotic and meiotic defects with resultant sterility. Herein, we describe the first genetic analysis of murine VRK1. Two lines of mice containing distinct gene-trap integrations into the Vrk1 locus were established. Insertion into intron 12 (GT12) spared VRK1 function, enabling the examination of VRK1 expression in situ. Insertion into intron 3 (GT3) disrupted VRK1 function, but incomplete splicing to the gene trap rendered this allele hypomorphic (~15% of …

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Spots Of Adult Male Red-Spotted Newts Are Redder And Brighter Than In Females: Evidence For A Role In Mate Selection?, Andrew K. Davis, Kristine L. Grayson Nov 2008

Spots Of Adult Male Red-Spotted Newts Are Redder And Brighter Than In Females: Evidence For A Role In Mate Selection?, Andrew K. Davis, Kristine L. Grayson

Biology Faculty Publications

As aquatic adults, eastern red-spotted newts (Notophthalmus v. viridescens) are generally green with two rows of dorsal spots, which vary in number between individuals and range in colour from orange to red. The function of these spots is unknown, but it is possible that they serve as sexual ornamentations and we examined this hypothesis by testing for sexual dimorphism in spot characteristics. We used an image analysis approach that has been used previously with this and other amphibian species to compare the number, size and colour – redness (hue score) and brightness – of spots in 100 male …

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Inhibition Of Nitric Oxide And Soluble Guanylyl Cyclase Signaling Affects Olfactory Neuron Activity In The Moth, Manduca Sexta, Caroline H. Wilson, Thomas A. Christensen, Alan J. Nighorn Jun 2007

Inhibition Of Nitric Oxide And Soluble Guanylyl Cyclase Signaling Affects Olfactory Neuron Activity In The Moth, Manduca Sexta, Caroline H. Wilson, Thomas A. Christensen, Alan J. Nighorn

Health Sciences and Kinesiology Faculty Articles

Nitric oxide is emerging as an important modulator of many physiological processes including olfaction, yet the function of this gas in the processing of olfactory information remains poorly understood. In the antennal lobe of the moth, Manduca sexta, nitric oxide is produced in response to odor stimulation, and many interneurons express soluble guanylyl cyclase, a well-characterized nitric oxide target. We used intracellular recording and staining coupled with pharmacological manipulation of nitric oxide and soluble guanylyl cyclase to test the hypothesis that nitric oxide modulates odor responsiveness in olfactory interneurons through soluble guanylyl cyclase-dependent pathways. Nitric oxide synthase inhibition resulted …

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