Life Sciences Commons^™

The Selfish Nature Of Generosity: Harassment And Food Sharing In Primates, Jeffrey R. Stevens

Jeffrey Stevens Publications

Animals may share food to gain immediate or delayed fitness benefits. Previous studies of sharing have concentrated on delayed benefits such as reciprocity, trade and punishment. This study tests an alternative model (the harassment or sharing–under–pressure hypothesis) in which a food owner immediately benefits because sharing avoids costly harassment from a beggar. I present an experiment that varies the potential ability of the beggar to harass, and of the owner to defend the food, to examine the effects of harassment on food sharing in two primate species: chimpanzees (Pan troglodytes) and squirrel monkeys (Saimiri boliviensis). For …

A Conceptual Framework For Non-Kin Food Sharing: Timing And Currency Of Benefits, Jeffrey R. Stevens, Ian C. Gilby

Jeffrey Stevens Publications

Many animal species, from arthropods to apes, share food. This paper presents a new framework that categorizes nonkin food sharing according to two axes: (1) the interval between sharing and receiving the benefits of sharing, and (2) the currency units in which benefits accrue to the sharer (especially food versus nonfood). Sharers can obtain immediate benefits from increased foraging efficiency, predation avoidance, mate provisioning, or manipulative mutualism. Reciprocity, trade, status enhancement and group augmentation can delay benefits. When benefits are delayed or when food is exchanged for nonfood benefits, maintaining sharing can become more difficult because animals face discounting and …

Deletion Of The Δ12-Oleic Acid Desaturase Gene Of A Nonaflatoxigenic Aspergillus Parasiticus Field Isolate Affects Conidiation And Sclerotial Development, Perng Kuang Chang, Richard A. Wilson, Nancy P. Keller, Thomas E. Cleveland

Fungal Molecular Plant-Microbe Interactions

Aims: To investigate how linoleic acid affects conidial production and sclerotial development in a strictly mitotic Aspergillus parasiticus field isolate as related to improving biocompetitivity of atoxigenic Aspergillus species.

Methods and Results: We disrupted A. parasiticus Δ12-oleic acid desaturase gene (odeA) responsible for the conversion of oleic acid to linoleic acid. We examined conidiation and sclerotial development of SRRC 2043 and three isogenic mutant strains deleted for the odeA gene (DodeA), either with or without supplementing linoleic acid, on one complex potato dextrose agar (PDA) medium and on two defined media: nitrate-containing Czapek agar (CZ) and Cove’s ammonium …

Two Δ9-Stearic Acid Desaturases Are Required For Aspergillus Nidulans Growth And Development, Richard A. Wilson, Perng-Kuang Chang, Agnieszka Dobrzyn, James B. Ntambi, Robert Zarnowski, Nancy P. Keller

Fungal Molecular Plant-Microbe Interactions

Unsaturated fatty acids are important constituents of all cell membranes and are required for normal growth. In the filamentous fungus Aspergillus nidulans, unsaturated fatty acids and their derivatives also influence asexual (conidial) and sexual (ascospore) sporulation processes. To investigate the relationship between fatty acid metabolism and fungal development, we disrupted the A. nidulans sdeA and sdeB genes, both encoding Δ9-stearic acid desaturases responsible for the conversion of palmitic acid (16:0) and stearic acid (18:0) to palmitoleic acid (16:1) and oleic acid (18:1). The effects of sdeA deletion on development were profound, such that growth, conidial and ascospore production were …

The Effects Of Habitat Resolution On Models Of Avian Diversity And Distributions: A Comparison Of Two Land-Cover Classifications, Joshua Lawler, Raymond O'Connor, Carolyn Hunsaker, K. Bruce Jones, Thomas Loveland, Denis White

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

Quantifying patterns is a key element of landscape analysis. One aspect of this quantification of particular importance to landscape ecologists is the classification of continuous variables to produce categorical variables such as land-cover type or elevation stratum. Although landscape ecologists are fully aware of the importance of spatial resolution in ecological investigations, the potential importance of the resolution of classifications has received little attention. Here we demonstrate the effects of using two different land-cover classifications to predict avian species richness and the occurrences of six individual species across the conterminous United States. We compared models built with a data set …

Genetic Diversity And Structure Of The Fisher (Martes Pennanti) In A Peninsular And Peripheral Metapopulation, Samantha M. Wisely, Steven W. Buskirk, Gregory A. Russell, Keith B. Aubry, William J. Zielinsky

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

Evolutionary processes can be strongly affected by landscape features. In vagile carnivores that disperse widely, however, genetic structure has been found to be minimal. Using microsatellite DNA primers developed for other mustelids, we found that populations of a vagile forest carnivore, the fisher (Martes pennanti), exhibit high genetic structure (F_ST = 0.45, SE = 0.07) and limited gene flow (Nm < 1) within a .1,600-km narrow strip of forested habitat; that genetic diversity decreases from core to periphery; and that populations do not show an equilibrium pattern of isolation-by-distance. Genetic structure was greater at the periphery than at the core of the distribution and our data fit a 1-dimensional model of stepping-stone range expansion. Multiple lines of paleontological and genetic evidence suggest that the fisher recently (<5,000 years ago) expanded into the mountain forests of the Pacific coast. The reduced dimensionality of the distribution of the fisher in western coastal forests appears to have contributed to the high levels of structure and decreasing diversity from north to south. These effects were likely exacerbated by human-caused changes to the environment. The low genetic diversity and high genetic structure of populations in the southern Sierra Nevada suggest that populations in this part of the geographic range are vulnerable to extinction.

Record High Wolf, Canis Lupus, Pack Density, L. David Mech, Shawn Tracy

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

This report documents a year-around Wolf (Canis lupus) density of 18.2/100 km² and a summer density of 30.8/100 km², in a northeastern Minnesota Wolf pack. The previous record was a summer density of 14.1/100 km², for a Wolf pack on Vancouver Island, British Columbia, Canada.

Cd46-Mediated Transduction Of A Species D Adenovirus Vaccine Improves Mucosal Vaccine Efficacy, Zenaido T. Camacho, Mallory A. Turner, Michael A. Barry, Eric A. Weaver

Nebraska Center for Virology: Faculty Publications

The high levels of preexisting immunity against Adenovirus type 5 (Ad5) have deemed Ad5 unusable for translation as a human vaccine vector. Low seroprevalent alternative viral vectors may be less impacted by preexisting immunity, but they may also have significantly different phenotypes from that of Ad5. In this study we compare species D Ads (26, 28, and 48) to the species C Ad5. In vitro transduction studies show striking differences between the species C and D viruses. Most notably, Ad26 transduced human dendritic cells much more effectively than Ad5. In vivo imaging studies showed strikingly different transgene expression profiles. The …

Phylogenetic Analyses Of Texas Isolates Indicate An Evolving Subtype Of The Clade B Feline Immunodeficiency Viruses, Eric A. Weaver, Ellen W. Collisson, Margaret Slater, Guan Zhu

Nebraska Center for Virology: Faculty Publications

Rigorous phylogenetic analyses were used to compare the nucleotide sequences of feline immunodeficiency virus strains isolated from Texas and throughout the world. The envelope V3-V4 sequences and capsid gene of the Texas isolates formed a cluster between subtypes B and E. Statistical comparisons with other published sequences confirmed that the Texas group is a unique cluster, possibly a new subtype, arising from subtype B.

A Method To Detect Oxidative Stress By Monitoring Changes In The Extracellular Antioxidant Capacity In Plant Suspension Cells, C. Jacyn Baker, Norton M. Mock

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

Detection of H₂O₂ in the supernatant of plant suspension cells is often used to indicate the time and extent of the oxidative burst during interactions with either bacteria or pathogen-related elicitors. We have found that suspensions of plant cells, depending on conditions, may produce considerable levels of extracellular phenolics that can function as antioxidants and prevent or suppress the detection of H₂O₂. These compounds can be used as substrates by extracellular peroxidases to scavenge stoichiometric amounts of H₂O₂. When this occurs during plant/pathogen interactions it can mask both the …

Comparison Of Three Methods Of Size Grading Channel Catfish Stockers, Bartholomew W. Green, David L. Heikes, Andrew E. Goodwin

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

The stocking of size-graded catfish into production ponds should increase production efficiency, but grading large numbers of fish with existing technology is laborious. We evaluated the effectiveness of a mechanical grader recently developed at the University of Arkansas at Pine Bluff (UAPB) relative to that of box and sock graders and assessed injuries sustained by stocker channel catfish Ictalurus punctatus during grading. Three 0.25-acre ponds were stocked at 11,777 lb/acre. Initial total length (TL) ranged from 6.3 to 15.7 in, and initial weight of individuals ranged from 0.04 to 1.10 lb. The fish population in each pond was divided into …

Tribute To Rod Gangwish And Mark Gustafson, John Owens

John Owens: Speeches and Appearances

President Williamson, honored guests and friends, it is such a pleasure to be here with you tonight, and such a privilege to deliver this tribute to our 2004 Nebraska Hall of Agricultural Achievement honorees, Rod Gangwish and Mark Gustafson.

Uaad Award Presentation Remarks, John Owens

John Owens: Speeches and Appearances

It's my great pleasure to be asked to participate in recognizing great employees for service to the university. I am pleased to be able to confer awards today upon two university employees whose work ethic and devotion to the university are exemplary.

Uaad Founders' Day, John Owens

John Owens: Speeches and Appearances

Because today is the birthday of Thomas Edison who was born in 1847 in Ohio, I suppose that you would expect me as today's speaker to have a special obligation to be inventive. Some of you probably know that for several years, Edison's birthday has been observed as National Science Youth Day, which sounds to me like a rather interesting invention itself. Youth is not a science and science is certainly not a youth, but I am perfectly willing to go along with the national celebration and wish a happy birthday to any science youth that I might happen to …

Opening Comments Before Master Conservationist Presentations, John Owens

John Owens: Speeches and Appearances

It is a real pleasure to participate in this recognition program honoring the 2004 Master-Conservationists. We are grateful for the partnership with the Omaha World Herald in this unique program. In an effort to keep the program in tune with current developments in soil and waster conservation, a special committee is considering the idea of including conservation easements in the 2005 program. Some members of the committee are in the audience tonight. We appreciate the efforts of members of the Omaha World Herald, Natural Resources Districts, the USDA Natural-Resources Conservation Service and the Institute of Agriculture and Natural Resources in …

Ianr Recognition Luncheon, John Owens

John Owens: Speeches and Appearances

What a pleasure it is to come together here to recognize and celebrate Outstanding work of members of our IANR community. It is even more of a treat to have three reasons to celebrate today as we recognize excellence with two IANR Exemplary Service Awards, two Dinsdale Family Faculty Awards, and the IANR Team Award.

Gudmundsen Sandhills Laboratory Open House, John Owens

John Owens: Speeches and Appearances

What a pleasure it is to be here with you today at the Gudmundsen Sandhills Laboratory Open House. I grew up a country boy in Texas, and any day I get to spend in rangeland is a good day to me.

2004 Nebraska Grazing Conference, John Owens

John Owens: Speeches and Appearances

It is both my privilege and pleasure to have the opportunity this morning to welcome you to the 2004 Nebraska Grazing Conference. I am sure you are looking forward to the next two days of great topics and excellent speakers. This is the fourth year this conference has brought people together to hear, to discuss, to exchange a wide variety of ideas. Reading through the list of conference sponsors and supporters, I think how fortunate we are in Nebraska to forge and foster such productive partnerships for the good of our state.

Moving Ahead In Lean Times: Nebraska Ag Relations Council, John Owens

John Owens: Speeches and Appearances

One day a rancher's prize bull was missing from the section of his land the railroad passed through. He filed suit against the railroad, wanting only to be paid a fair-price of the bull. A big-city lawyer arrived in the rancher's small town to represent the railroad in the case and quickly cornered the rancher, pressuring him to settle out of court.

Ag At The Crossroads, John Owens

John Owens: Speeches and Appearances

Thank you for inviting me to be here with you today. It is always such a pleasure to be asked to talk about the ways the Institute of Agriculture and Natural Resources benefits Nebraskans, Nebraska, and our state's economy. I am proud of the real difference our work makes in Nebraska's future and in Nebraskans' lives.

Agriculture Builders Of Nebraska, Inc., John Owens

John Owens: Speeches and Appearances

What a pleasure it is to be with you here this morning! And How startling it is to realize a whole year has passed since we last gathered at this meeting. So much has occurred in that year.

Splinter Dedication, John Owens

John Owens: Speeches and Appearances

This man who grew up on an irrigated farm near North Platte was inducted into the National Academy of Engineering in 1984 for invention and development of aerial-spray systems and harvesting systems, the only Nebraskan elected to that esteemed academy. Six patents are based on his research.

Omtvedt Innovation Awards Presented To Chris Calkins, Steven Jones, Rodger Johnson, And Sheila Scheideler, John Owens

John Owens: Speeches and Appearances

It's a great pleasure to welcome you to this very first recognition ceremony for the Omtvedt Innovation Awards. We are present here to honor innovation strengths of the Institute of Agriculture and Natural Resources, and certainly the four faculty members receiving today's awards are greatly deserving of this recognition. Just hearing about their work is gratifying!

The Southwestern Association Of Parasitologists: The First 35 Years: 1967–2002, Donald W. Duszynski

Harold W. Manter Laboratory of Parasitology: Faculty Publications

First two paragraphs:

It is likely that the idea to organize southwestern parasitologists into a regional group originated over cocktails one night in the late 1950s during a regional or national meeting. What is clear is that two men—Drs. Robert E. Kuntz and Donald V. Moore— were instrumental in turning the idea into what has become, in reality, the Southwestern Association of Parasitologists (SWAP).

Dr. J. Teague Self (personal communication, 1981) stated, “The beginning of SWAP was an idea of Robert Kuntz who felt that something could be gained if several of us here in the southwest could get together …

Some Aspects Of The Biology And Life History Of Bothitrema Bothi (Monogenea: Bothitrematidae) From The Flounder Scophthalmus Aquosus (Bothidae) From New Jersey, Usa, Sherman S. Hendrix

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Bothitrema bothi (MacCallum, 1913), a monopisthocotylean monogenean (Bothitrematidae) found on gills and occasionally on the olfactory rosette within the nares of the bothid flounder, Scophthalmus aquosus (Mitchill, 1815), is distributed along the Atlantic coast of the USA from Woods Hole, Massachusetts to Delaware Bay. This study details aspects of the morphology, microecology and biology of the oncomiracidium, juvenile and adult. Adult worms occur almost exclusively between rakers on the first and second gill arches while juveniles occupy secondary gill filaments. Analysis of variance revealed significant arch, side and position effects. Worm attachment and position is maintained largely by suction generated …

Cardicola Forsteri (Digenea: Sanguinicolidae) From The Heart Of A Northern Bluefin Tuna, Thunnus Thynnus (Scombridae), In The Northwest Atlantic Ocean, Stephen A. Bullard, Robert J. Goldstein, Robert H. Goodwin Iii, Robin M. Overstreet

Harold W. Manter Laboratory of Parasitology: Faculty Publications

We report a specimen of Cardicola forsteri Cribb, Daintith, and Munday, 2000 (Digenea: Sanguinicolidae) from the lumen of the heart of a northern bluefin tuna, Thunnus thynnus (Linnaeus, 1758) (Scombridae), that was 218 cm in total length (TL) and caught in the northwest Atlantic Ocean 12 km south of Cape Lookout, North Carolina. The hearts of 12 similarly sized northern bluefin tuna (127–262 cm TL) from George’s Bank, northwest Atlantic Ocean, were not infected. This is the first report of C. forsteri from a wild host and of a sanguinicolid from any scombrid in the northwest Atlantic Ocean. Bluefin tuna …

Morphology Predicts Suction Feeding Performance In Centrarchid Fishes, Andrew M. Carroll, Peter C. Wainwright, Stephen H. Huskey, David C. Collar, Ralph G. Turingan

Ocean Engineering and Marine Sciences Faculty Publications

Suction feeding fish differ in their capacity to generate subambient pressure while feeding, and these differences appear to relate to morphological variation. We developed a morphological model of force transmission in the fish head and parameterized it with measurements from individual fish. The model was applied to 45 individuals from five species of centrarchid fishes: Lepomis macrochirus, Lepomis punctatus, Lepomis microlophus, Micropterus salmoides and Pomoxis nigromaculatus. Measurements of epaxial cross-sectional area, epaxial moment arm, buccal area and buccal area moment arm were combined to estimate pressure generation capacity for individual fish. This estimation was correlated with pressure measured in fish …

Aminoacyl-Trnas: Setting The Limits Of The Genetic Code, Michael Ibba, Dieter Söll

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Aminoacyl-tRNAs (aa-tRNAs) are simple molecules with a single purpose—to serve as substrates for translation. They consist of mature tRNAs to which an amino acid has been esterified at the 3′-end. The 20 different types of aa-tRNA are made by the 20 different aminoacyl-tRNA synthetases (aaRSs, of which there are two classes), one for each amino acid of the genetic code (Ibba and Söll 2000). This would be fine if it were not for the fact that such a straightforward textbook scenario is not true in a single known living organism. aa-tRNAs lie at the heart of gene expression; they interpret …

Evaluation Of Artificial Lighting Sources For The Acquisition Of Color Infrared Imagery Under Glasshouse Conditions, Kenneth R. Summy, Christopher R. Little, Ruben A. Mazariegos, Diana Lee Hinojosa-Kettelkamp, Jeri Carter, Shireen Yousef, Robert Valdez

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

English: Research was conducted to evaluate the spectral properties, illumination intensities and lighting patterns of four basic categories of bulbs and lamps which could conceivably serve as sole lighting sources for the acquisition of color infrared (CIR) imagery under glasshouse conditions. Bulbs and lamps in two major categories (fluorescent tubes and sodium- and mercury-vapor glasshouse lamps) were deemed unsuitable for this purpose either because they emitted little or no nearinfrared (NIR) radiation or because they imparted an overall bluish cast that seriously degraded the quality of CIR imagery. All of the incandescent and quartz halogen lamps evaluated in these studies …

Regional Ecological Resource Assessment Of The Rio Grande Riparian Corridor: A Multidisciplinary Approach To Understanding Anthropogenic Effects On Riparian Communities In Semi-Arid Environments, Jay Raney, Amy Neuenschwander, Frank W. Judd, Gene Paull, Melba Crawford, Robert I. Lonard, Tatiana Encheva, Thomas Tremblay, William White

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Biology)

Riparian ecosystems of the Southwestern United States are among the most productive ecosystems of North America. The rapid decline of these ecosystems throughout the United States, including the Lower Rio Grande Valley, has made riparian conservation a focal issue. This was a multidisciplinary study of riparian communities along the Lower Rio Grande Valley of Texas and Mexico. The objectives of this research project were to: (1) acquire and analyze high-resolution, remotely sensed data from multiple sensors; (2) integrate existing and new field data and remotely sensed data into a geographic information system (GIS); (3) ascertain whether the native vegetation communities …