Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 10 of 10

Full-Text Articles in Entire DC Network

Daily Energy Expenditure Of Florida Scrub-Jays (Aphelocoma Coerulescens) In Suburban And Wildland Landscapes, Hugh I. Ellis, Reed Bowman Jan 2020

Daily Energy Expenditure Of Florida Scrub-Jays (Aphelocoma Coerulescens) In Suburban And Wildland Landscapes, Hugh I. Ellis, Reed Bowman

Biology: Faculty Scholarship

Urbanization alters ecological systems, disturbance regimes, food webs, and a variety of other processes that can influence local flora and fauna. In birds, most studies have focused on behavioral or demographic responses to altered conditions; however, the physiological mechanisms associated with these responses have been understudied. We have previously documented shifts in foraging behavior because of the availability of human-provided food; we sought to see if this was driven by or associated with a change in field metabolic rates. We measured field metabolic rates (FMR), a measure of daily energy expenditure (DEE), of Florida Scrub-Jays (Aphelocoma coerulescens) in 2 habitats …


Polyglutamine Repeat Proteins Disrupt Actin Structure In Drosophila Photoreceptors., Annie Vu, Tyler Humphries, Sean Vogel, Adam Haberman Dec 2018

Polyglutamine Repeat Proteins Disrupt Actin Structure In Drosophila Photoreceptors., Annie Vu, Tyler Humphries, Sean Vogel, Adam Haberman

Biology: Faculty Scholarship

Expansions of polygutamine-encoding stretches in several genes cause neurodegenerative disorders including Huntington's Disease and Spinocerebellar Ataxia type 3. Expression of the human disease alleles in Drosophila melanogaster neurons recapitulates cellular features of these disorders, and has therefore been used to model the cell biology of these diseases. Here, we show that polyglutamine disease alleles expressed in Drosophila photoreceptors disrupt actin structure at rhabdomeres, as other groups have shown they do in Drosophila and mammalian dendrites. We show this actin regulatory pathway works through the small G protein Rac and the actin nucleating protein Form3. We also find that Form3 has …


Retrotransposons Are The Major Contributors To The Expansion Of The Drosophila Ananassae Muller F Element, William Leung, Sarah C. R. Elgin, Adam Haberman Jan 2017

Retrotransposons Are The Major Contributors To The Expansion Of The Drosophila Ananassae Muller F Element, William Leung, Sarah C. R. Elgin, Adam Haberman

Biology: Faculty Scholarship

The discordance between genome size and the complexity of eukaryotes can partly be attributed to differences in repeat density. The Muller F element (~5.2 Mb) is the smallest chromosome in Drosophila melanogaster, but it is substantially larger (>18.7 Mb) in Drosophila ananassae. To identify the major contributors to the expansion of the F element and to assess their impact, we improved the genome sequence and annotated the genes in a 1.4 Mb region of the D. ananassae F element, and a 1.7 Mb region from the D element for comparison. We find that transposons (particularly LTR and LINE retrotransposons) …


Drosophila Muller F Elements Maintain A Distinct Set Of Genomic Properties Over 40 Million Years Of Evolution, Adam Haberman Jan 2015

Drosophila Muller F Elements Maintain A Distinct Set Of Genomic Properties Over 40 Million Years Of Evolution, Adam Haberman

Biology: Faculty Scholarship

The Muller F element (4.2 Mb, ~80 protein-coding genes) is an unusual autosome of Drosophila melanogaster; it is mostly heterochromatic with a low recombination rate. To investigate how these properties impact the evolution of repeats and genes, we manually improved the sequence and annotated the genes on the D. erecta, D. mojavensis, and D. grimshawi F elements and euchromatic domains from the Muller D element. We find that F elements have higher transposon density (25%–50%) than euchromatic reference regions (3%–11%). Among the F elements, D. grimshawi has the lowest transposon density (particularly DINE-1: 2% versus 11%–27%). F element genes have …


Temperature Regulation And The Constraints Of Climate In The Eared Grebe, Hugh I. Ellis, Joseph R. Jehl Jr Feb 2003

Temperature Regulation And The Constraints Of Climate In The Eared Grebe, Hugh I. Ellis, Joseph R. Jehl Jr

Biology: Faculty Scholarship

Eared Grebes (Podiceps nigricollis) encounter a variety of climatic regimes in their annual cycle. The most dramatic occur while on staging areas in autumn. We investigated the thermoregulatory abilities of the Eared Grebe to determine how they coped with these climate changes during staging. The basal metabolic rate (BMR) was higher than predicted. Mass-specific BMR was 1.212 mL O2/g·h for birds averaging 317 g. The thermoneutral zone is wide and extended from 15°C to 38°C. Minimal thermal conductance and average body temperature were not unusual. We conclude that Eared Grebes live most of the year under thermoneutral conditions and that …


Energetics Of Free-Ranging Seabirds, Hugh I. Ellis, Geir Wing Gabrielsen Jan 2002

Energetics Of Free-Ranging Seabirds, Hugh I. Ellis, Geir Wing Gabrielsen

Biology: Faculty Scholarship

No abstract provided.


Summer Activity Cost Of Eared Grebes At Mono Lake, Hugh I. Ellis May 1994

Summer Activity Cost Of Eared Grebes At Mono Lake, Hugh I. Ellis

Biology: Faculty Scholarship

No abstract provided.


Total Body Water And Body Composition In Phalaropes And Other Birds, Hugh I. Ellis, Joseph R. Jehl Jr Jan 1991

Total Body Water And Body Composition In Phalaropes And Other Birds, Hugh I. Ellis, Joseph R. Jehl Jr

Biology: Faculty Scholarship

Contrary to some reviews, total body water (TBW) may fall below the expected value of about 65% in birds if measured as a percentage of total body mass. However, water constitutes a relatively stable proportion (659%-70%) of body composition when measured as a percentage of lean body mass (LBM). We demonstrate this by using data from two migratory phalaropes (Phalaropus tricolor and Phalaropus lobatus), which exhibit inverse relationships between TBW and body mass and between TBW and fat content. As the phalaropes fatten before migration, lipids increase but not at the expense of water, which also increases with gains in …


Incubation Energetics Of The Laysan Albatross, Ted N. Pettit, K A. Nagy, Hugh I. Ellis, G Causey Whittow Jan 1988

Incubation Energetics Of The Laysan Albatross, Ted N. Pettit, K A. Nagy, Hugh I. Ellis, G Causey Whittow

Biology: Faculty Scholarship

The energy expenditure of incubating and foraging Laysan Albatross (Diomedea immutabilis, mean body weight 3.07 kg) was estimated by means of the doubly-la- belled water technique. During incubation, the energy expenditure was similar to that of resting birds that were not incubating an egg. The energy expenditure of foraging albatross (2072 kJ/day) was 2.6 times that of resting birds. It was concluded that the energy expenditure of the tropical Laysan Albatross was not less than that of species foraging over cold, high-latitude oceans. An energy budget compiled for an incubating pair of albatross revealed that the energy expenditure of the …


Metabolism And Solar Radiation In Dark And White Herons Nesting In Hot Climates, Hugh I. Ellis Mar 1980

Metabolism And Solar Radiation In Dark And White Herons Nesting In Hot Climates, Hugh I. Ellis

Biology: Faculty Scholarship

Metabolism, body temperature (Tb), and feather reflectance was measured for dark Louisiana herons (LOU), little blue herons (LB), snowy egrets (SE), and cattle egrets (CE); only LOU nest preferentiallyin shade. The reflectance of LOU and adult LB was 13%-15%; it was 80%-82% for SE, CE, and immature (white) LB. Tb for all four species approximated 40 C; hypothermy was never observed. Basal metabolism (HJb) was 107% of the expected level for LOU, 85% for SE and CE, and 66% for LB. Minimal thermal conductance (C) was calculated as approximately 131% of the expected value for LOU, 115% for SE and …