Life Sciences Commons^™

U.S. Drought Monitor, December 31, 2013, Matthew Rosencrans

United States Agricultural Commodities in Drought Archive

Drought map of U.S. for December 31, 2013 (12/31/13) plus: U.S. crop areas experiencing drought (map), Approximate percentage of crop located in drought, by state (bar graph), Percent of crop area located in drought, past 52 weeks (line graph) for: Corn, Soybeans, Hay, Cattle, Winter wheat.

U.S. Drought Monitor, December 24, 2013, Matthew Rosencrans

United States Agricultural Commodities in Drought Archive

Drought map of U.S. for December 24, 2013 (12/24/13) plus: U.S. crop areas experiencing drought (map), Approximate percentage of crop located in drought, by state (bar graph), Percent of crop area located in drought, past 52 weeks (line graph) for: Hay, Cattle, Winter wheat.

Beef Cattle Body Temperature During Climatic Stress: A Genome-Wide Association Study, Jeremy T. Howard, Stephen D. Kachman, Warren M. Snelling, E. John Pollak, Daniel C. Ciobanu, Larry A. Kuehn, Matthew L. Spangler

Department of Animal Science: Faculty Publications

Cattle are reared in diverse environments and collecting phenotypic body temperature (BT) measurements to characterize BT variation across diverse environments is difficult and expensive. To better understand the genetic basis of BT regulation, a genome-wide association study was conducted utilizing crossbred steers and heifers totaling 239 animals of unknown pedigree and breed fraction. During predicted extreme heat and cold stress events, hourly tympanic and vaginal BT devices were placed in steers and heifers, respect i v e l y. I n d i v i dua l s we r e genotyped with t h e BovineSNP50K_v2 assay and data …

U.S. Drought Monitor, December 17, 2013, Mark D. Svoboda

United States Agricultural Commodities in Drought Archive

Drought map of U.S. for December 17, 2013 (12/17/13) plus: U.S. crop areas experiencing drought (map), Approximate percentage of crop located in drought, by state (bar graph), Percent of crop area located in drought, past 52 weeks (line graph) for: Corn, Soybeans, Hay, Cattle, Winter wheat.

U.S. Drought Monitor, December 10, 2013, Michael J. Brewer

United States Agricultural Commodities in Drought Archive

Drought map of U.S. for December 10, 2013 (12/10/13) plus: U.S. crop areas experiencing drought (map), Approximate percentage of crop located in drought, by state (bar graph), Percent of crop area located in drought, past 52 weeks (line graph) for: Corn, Soybeans, Hay, Cattle, Winter wheat.

Making Chlamydomonas Reinhardtii A Better Model Organism: Tackling The Inefficiency Of Nuclear Transgene Expression And Improving Methods For The Generation And Characterization Of Insertional Mutant Libraries, Thomas M. Plucinak

Department of Biochemistry: Dissertations, Theses, and Student Research

The green algal species Chlamydomonas reinhardtii possesses many beneficial features that have made it a useful model organism for many decades. Many types of experimentation however are difficult to conduct with this organism due to the relative under-development of genetic tools available for use. Tasks such as transgene expression, overexpression of proteins of interest (POIs) or site specific genomic modification that are routine in other more facile microbial model organisms such as Escherichia coli and yeast are difficult to accomplish in C. reinhardtii. The second chapter of this thesis describes the development of a novel nuclear transgene expression system …

Studies On The Regulation Of Fgf21 Gene Expression By (R)-Α-Lipoic Acid: Mechanistic Insight Into The Lipid Lowering Properties Of A Dithiol Dietary Molecule, Xiaohua Yi

Department of Nutrition and Health Sciences: Dissertations, Theses, and Student Research

Controlling blood lipids is a major public health challenge of our time. The pleiotropic hormone-like polypeptide fibroblast growth factor 21 (FGF21) was recently recognized as a potent modulator of lipid and glucose metabolism and a promising treatment strategy for obesity related metabolic disorders, including dyslipidemia. A cost effective and practical alternative to the administration of recombinant FGF21 is to stimulate endogenous FGF21 production through diet. Our research identified (R)-a-lipoic acid (LA), a naturally occurring enzyme cofactor and dietary molecule found in green leafy vegetable and red meat, as an inducer of FGF21 expression. LA stimulated FGF21 production, demonstrated by a …

Biotinylation Of The C-Myc Promoter Binding Protein Mbp-1 Decreases C-Myc And Cox-2 Expression In Mammary Carcinoma Mcf-7 Cells, Jie Zhou

Department of Nutrition and Health Sciences: Dissertations, Theses, and Student Research

Biotin feeding in a Balb/c mouse model of breast cancer suggest that the tumor load is ~100% greater in biotin-deficient mice compared with biotin-sufficient controls, and that the increase is associated with metastasis rather than new tumors. The oncogenes c-Myc and COX-2 are implicated in cancer metastasis, and their expressions are repressed by binding of MBP-1 to the promoter. Mass spectrometry studies, designed to discover novel biotin-containing proteins, suggest that lysine residues K10 and K12 in the c-Myc promoter binding protein (MBP-1) contains covalently bound biotin (MBP-1bio). We hypothesized that biotinylation of MBP-1 increases the binding of MBP-1 to the …

U.S. Drought Monitor, December 3, 2013, Michael J. Brewer

United States Agricultural Commodities in Drought Archive

Drought map of U.S. for December 3, 2013 (12/3/13) plus: U.S. crop areas experiencing drought (map), Approximate percentage of crop located in drought, by state (bar graph), Percent of crop area located in drought, past 52 weeks (line graph) for: Corn, Soybeans, Hay, Cattle, Winter wheat.

Changes In Poa Annua Populations In Response To Herbicides And Plant Growth Regulators, Jesse Brown

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Poa annua (annual bluegrass; ABG) is an invasive weedy species in turfgrass. Herbicides and plant growth regulators (PGRs) are often used for ABG control, providing limited or inconsistent results. Identifying shifts in ABG populations in response to these treatments would be beneficial for understanding inconsistent control. Our research employed amplified fragment length polymorphic (AFLP) markers with the objective to determine if there are changes in genetic structure of ABG populations after multiple-year season-long control programs in three states. Annual bluegrass was sampled after the second or third year of seven different season-long ABG treatments consisting of herbicide or PGR applications. …

Transcriptional Regulation Of The Porcine Gnrh Receptor Gene By Glucocorticoids, Chanho Lee

Department of Animal Science: Dissertations, Theses, and Student Research

Binding of GnRH to its receptor (GnRHR) stimulates the synthesis and secretion of the gonadotropins, as well as up-regulation of GnRHR. Thus, the interaction between GnRH and GnRHR represents a central point for regulation of reproduction. Glucocorticoids alter reproduction by reducing GnRH responsiveness of gonadotropes within the anterior pituitary gland, potentially via transcriptional regulation of the GnRHR gene. Investigation into this mechanism, however, revealed that the murine GnRHR gene was stimulated by glucocorticoids. To determine the effect of glucocorticoids on porcine GnRHR gene expression, gonadotrope-derived αT3-1 cells were transiently transfected with a vector containing 5118 bp of 5’ flanking sequence …

Predicting Invasion Risk Of Non-Native Plants Using A Modified I-Rank Assessment, Justin B. Williams

School of Natural Resources: Dissertations, Theses, and Student Research

Biological invasions are a global problem responsible for native species declines worldwide. Understanding the invasion risk from non-native species is important in establishing management goals and making decisions for managing native ecosystems. Useful modeling methods for quantifying or predicting invasion risk should consider research needs, data availability, and operate at an appropriate scale. I evaluated risk assessment methods towards answering a specific research question; which plant species pose the greatest risk of becoming invasive or having the greatest negative impact in Nebraska? I selected the I-Rank assessment method, which consists of 20 questions grouped into four risk categories or Subranks: …

A Population Model For Walleye In Nebraska Irrigation Reservoirs, Robert A. Kill

School of Natural Resources: Dissertations, Theses, and Student Research

Understanding how and why fish population size changes between years is a central theme in fisheries ecology. Fishery agencies have limited time and financial resources, thus there is a need for a quantitative way to direct the limited time and financial resources so agencies can manage fisheries more efficiently. I developed a tool for fishery managers that synthesizes common population indices and evaluated the relative importance of those indices given varying uncertainty in age-0 walleye Sander vitreus survival. Under most circumstances, I determined that resources are best utilized in reducing age-0 survival uncertainty when understanding walleye population growth. I applied …

Determining Scaphirhynchus Sturgeon Population Demographics And Dynamics: Implications For Range-Wide Management, Recovery, And Conservation, Martin J. Hamel

School of Natural Resources: Dissertations, Theses, and Student Research

Sturgeons (Acipenseridae) have experienced world-wide declines as a result of anthropogenic effects such as over-harvest, habitat degradation, altered flow regimes, and pollution. Nearly all European and Asian sturgeon species have experienced population declines and have subsequently been classified as either threatened or endangered. North American sturgeons have experienced a similar plight in that all eight native sturgeon species are listed as endangered, threatened, or of special concern. Direct linkages between North American sturgeon declines and anthropogenic effects are difficult to assess due to scale considerations, fluctuating environmental conditions, difficulty in capture, and the interaction of all these effects. To recover, …

Anoxia Tolerance Of Forensically Important Calliphorids, Melissa M. Lein

School of Natural Resources: Dissertations, Theses, and Student Research

Forensically important blow flies, Diptera: Calliphoridae, are among the first organisms to colonize carrion. After eggs hatch, the larvae of most blow fly species feed in an aggregation or “mass.” While in this mass larvae may experience periods of no oxygen (anoxia), little oxygen (hypoxia), or normal oxygen (normoxia), but the tolerance of blow fly larvae to severe hypoxic conditions is not known. I tested the anoxia tolerance of four species of calliphorids (Calliphora vicina, Cochliomyia macellaria, Lucilia sericata, and Phormia regina), using third stage larvae across five temperatures. Experiments were conducted by exposing larvae to pure nitrogen …

Evaluation Of Three Nest Searching Methods For Ring-Necked Pheasant, Jeffery W. Stackhouse, Kevin K. Sedivec, Benjamin A. Geaumont

The Prairie Naturalist

Ring-necked pheasant (Phasianus colchicus) are a highly sought after game bird and as such, much research has been conducted regarding their ecology (Warner 1981, Trautman 1982, Johnson and Knue 1989). Perhaps the most investigated aspect of pheasant ecology is the species’ reproductive season (e.g. Linder et al. 1960, Dumke and Pils 1979, Leif 1994) with many studies focusing on nesting habitat (Baskett 1947, Clark et al. 1999). Results from previous research have acknowledged the difficulty associated with locating pheasant nests in their preferred cover types (Hanson 1970, Evrard 2000). Studies of pheasant nesting ecology have been based on …

Dual Capture Of A Piñon Deer Mouse And A Silky Pocket Mouse Resulting In Consumption Of The Smaller Animal, Jon C. Pigage, Roger D. Peyton

The Prairie Naturalist

Intraspecific dual captures of rodents are uncommon, but not rare. There are several reports of brown rats (Rattus norvegicus), white-footed deer mice (Peromyscus leucopus), North American deer mice (P. maniculatus), western harvest mice (Reithrodontomys megalotis) and meadow voles (Microtus pennsylvanicus) caught simultaneously in the same trap (i.e. a door-closing live-trap; Davis 1955, Getz 1961, Blaustein and Rothstein 1978, Jenkins and Llewellyn 1981, Novak 1983). Some reports are incidental whereas others are interpreted as social associations or bonding between conspecifics. Interspecific dual captures are rarely reported in the literature. The earliest report of …

Red-Tailed Hawk Nesting In Kansas: Influence Of Landscape Characteristics, William Langley

The Prairie Naturalist

Factors that affect nest site selection in red-tailed hawks (Buteo jamaicensis) include the physical features surrounding the nest and landscape characteristics. Features surrounding nests include: tree height, tree diameter (dbh), percent canopy cover, slope, nest openness, and density of woody plants or shrubs (Titus and Mosher 1981, Bechard et al. 1990, Tietje et al. 1997, Actkinson et al. 2007). Landscape characteristics that influence nest-site selection by red-tailed hawks vary across regions. In Georgia, red-tailed hawks selected nest site in areas with greater area of agriculture and open pasture (Moorman and Chapman 1996), whereas in Oklahoma prairies, the hawks …

Associations Between Iron Concentration And Productivity In Montane Streams Of The Black Hills, South Dakota, Cari-Ann Hayer, Benjamin M. Holocmb, Steven R. Chipps

The Prairie Naturalist

Iron is an important micronutrient found in aquatic systems that can influence nutrient availability (e.g. phosphorus) and primary productivity. In streams, high iron concentrations often are associated with low pH as a result of acid mine drainage, which is known to affect fish and invertebrate communities. Streams in the Black Hills of South Dakota are generally circumneutral in pH, yet select streams exhibit high iron concentrations associated with natural iron deposits. In this study, we examined relationships among iron concentration, periphyton biomass, macroinvertebrate abundance, and fish assemblages in four Black Hills streams. The stream with the highest iron concentration (~5 …

Use Of Seeded Exotic Grasslands By Wintering Birds, Andrew D. George, Timothy J. O'Connell, Karen R. Hickman, David M. Lesliee Jr.

The Prairie Naturalist

Despite widespread population declines of North American grassland birds, effects of anthropogenic disturbance on wintering habitat of this guild remain poorly understood. We compared avian abundance and habitat structure in fields planted to the exotic grass Old World bluestem (Bothriochloa ischaemum; OWB) to that in native mixed-grass prairie. During winters of 2007–2008 and 2008–2009, we conducted bird and vegetation surveys in six native grass and six OWB fields in Garfield, Grant, and Alfalfa counties, Oklahoma. We recorded 24 species of wintering birds in native fields and 14 species in OWB monocultures. While vegetation structure was similar between field …

How Important Is A Quality Manuscript Review?, Christopher N. Jacques

The Prairie Naturalist

Temperatures are finally starting to cool a bit (for those of us in the northern Great Plains region) and Thanksgiving break is just around the corner.

I offer my reflections in the spirit of encouraging each of you to take a break from your professional obligations and spend time with friends and family enjoying nature and everything it has to offer this fall.

Salamander Colonization Of Chase Lake, Stutsman County, North Dakota, David M. Mushet, Kyle I. Mclean, Craig A. Stockwell

The Prairie Naturalist

Salt concentrations in lakes are dynamic. In the western United States, water diversions have caused significant declines in lake levels resulting in increased salinity, placing many aquatic species at risk (Galat and Robinson 1983, Beutel et al. 2001). Severe droughts can have similar effects on salt concentrations and aquatic communities (Swanson et al. 2003). Conversely, large inputs of water can dilute salt concentrations and contribute to community shifts (Euliss et al. 2004).

Chase Lake is a large, shallow, alkaline lake in east-central North Dakota most famously known for supporting one of the largest breeding colonies of the American white pelican …

A Simple Device For Measuring The Minimum Current Velocity To Maintain Semi-Buoyant Fish Eggs In Suspension, Julias S. Mueller, Brandon D. Cheek, Qingman Chen, Jillian Groeschel, Shannok K. Brewer, Timothy B. Grabowski

The Prairie Naturalist

Pelagic broadcast spawning cyprinids are common to Great Plains rivers and streams. This reproductive guild produces non-adhesive semi-buoyant eggs that require sufficient current velocity to remain in suspension during development. Although studies have shown that there may be a minimum velocity needed to keep the eggs in suspension, this velocity has not been estimated directly nor has the influence of physicochemical factors on egg buoyancy been determined. We developed a simple, inexpensive flow chamber that allowed for evaluation of minimum current velocity needed to keep semi-buoyant eggs in suspension at any time frame during egg development. The device described here …

Genetic Variability Of Spined Soldier Bugs (Hemiptera: Pentatomidae) Sampled From Distinct Field Sites And Laboratory Colonies In The United States, Fatima Mustafa, Muhammad Ullah, Kathleen M. Kneeland, Thomas A. Coudron, W. Wyatt Hoback, S. R. Skoda, Jaime Molina-Ochoa, John E. Foster

Department of Entomology: Faculty Publications

The spined soldier bug, Podisus maculiventris (Say), is an important biological control agent of agricultural and forest pests; and it preys on eggs and larvae of lepidopteran and coleopteran species. Genetic variability among field samples collected from Michigan, Mississippi, Missouri, Florida and established laboratory colonies was examined using Amplified Fragment Length Polymorphism-Polymerase Chain Reaction (AFLP-PCR). Four AFLP primer pairs generated a total of 340 molecular markers for evaluation. Results from Analysis of Molecular Variance showed that the majority of the genetic variation occurred within populations (individuals from each sample site). Nei’s method indicated reduced genetic diversity in laboratory populations compared …

Impact Of Wheat Streak Mosaic Virus And Triticum Mosaic Virus On Transmission By Aceria Tosichella Keifer (Eriophyidae) And Virus Epidemiology In Wheat, Camila F. De Oliveira

Department of Entomology: Dissertations, Theses, and Student Research

The wheat curl mite (WCM), Aceria tosichella Keifer, transmits a complex of viruses, Wheat streak mosaic virus (WSMV), Triticum mosaic virus (TriMV) and Wheat mosaic virus (WMoV), to wheat, Triticum aestivum, in the Great Plains. Co-infection of wheat by these viruses is frequently observed, increasing disease severity and yield loss.

Current genetic work classifies WCM populations into two genotypes, Type 1 and Type 2. It has been shown that different mite genotypes are able to transmit viruses at varying rates. WCM-virus relations are very specific and can impact vector biology. In this study, the primary objective was to determine …

Population Occurrence And Pathogen Prevalence Of Lone Star (Acari: Ixodidae) Ticks Collected From Southeast Nebraska, Amanda C. Maegli

Department of Entomology: Dissertations, Theses, and Student Research

Lone star tick, Amblyomma americanum (L.), has recently become established in Nebraska; therefore, local biology, ecology, and tick-borne disease risk are not known. Research was conducted to determine monthly questing activity, establishment, and pathogenic microorganisms associated with the lone star tick in Nebraska.

Lone star tick populations were collected from May through August, 2012 in six sites in southeast Nebraska using carbon dioxide (CO₂) traps. A total of 747 adults, 3,076 nymphs, and 1,289 larvae were collected. Total ticks collected and monthly activity were significantly different for each site.

A semi-randomized sample of 251 adult ticks were selected …

Toxic And Repellent Effects Of Pyrethroids Used In Orchards On The Honey Bee, Apis Mellifera L. (Hymenoptera: Apidae), Erin M. Ingram

Department of Entomology: Dissertations, Theses, and Student Research

Managed honey bee colonies provide valuable pollination services and are rented by fruit orchards to improve fruit quality and yield. The placement of colonies in this agricultural setting increases the possibility of exposure to pyrethroids used for broad-spectrum pest control in orchards. Although highly toxic to bees, pyrethroids are believed to pose a relatively low hazard due to their low application rates in the field as well as their contact repellent properties. Previous studies have noted a decrease in foraging visits following pyrethroid application possibly preventing bees from acquiring a lethal dose in the field.

This research quantified behaviors associated …

Loss Of Vascular Endothelial Growth Factor A (Vegfa) Isoforms In The Testes Of Male Mice Causes Subfertility, Reduces Sperm Numbers, And Alters Expression Of Genes That Regulate Undifferentiated Spermatogonia, Ningxia Lu, Kevin M. De Avila, Debra T. Clopton, William E. Pohlmeier, Vanessa M. Brauer, Renee M. Mcfee, John S. Weber, Napoleone Ferrara, David W. Silversides, Andrea S. Cupp

Department of Animal Science: Faculty Publications

Vascular endothelial growth factor A (VEGFA) isoform treatment has been demonstrated to alter spermatogonial stem cell homeostasis. Therefore, we generated pDmrt1-Cre;Vegfa^−/− (knockout, KO) mice by crossing pDmrt1-Cre mice to floxed Vegfa mice to test whether loss of all VEGFA isoforms in Sertoli and germ cells would impair spermatogenesis. When first mated, KO males took 14 days longer to get control females pregnant (P < .02) and tended to take longer for all subsequent parturition intervals (9 days; P < .07). Heterozygous males sired fewer pups per litter (P < .03) and after the first litter took 10 days longer (P < .05) to impregnate females, suggesting a more progressive loss of fertility. Reproductive organs were collected from 6-month-old male mice. There were fewer sperm per tubule in the corpus epididymides (P < .001) and fewer ZBTB16-stained undifferentiated spermatogonia (P < .003) in the testes of KO males. Testicular mRNA abundance for Bcl2 (P < .02), Bcl2:Bax (P < .02), Neurog3 (P < .007), and Ret was greater (P = .0005), tended to be greater for Sin3a and tended to be reduced for total Foxo1 (P < .07) in KO males. Immunofluorescence for CD31 and VE-Cadherin showed no differences in testis vasculature; however, CD31-positive staining was evident in undifferentiated spermatogonia only in KO testes. Therefore, loss of VEGFA isoforms in Sertoli and germ cells alters genes necessary for long-term maintenance of undifferentiated spermatogonia, ultimately reducing sperm numbers and resulting in subfertility.

Atf3 Expression In The Corpus Luteum: Possible Role In Luteal Regression, Dagan Mao, Xiaoying Hou, Heather Talbott, Robert A. Cushman, Andrea S. Cupp, John S. Davis

Department of Animal Science: Faculty Publications

The present study investigated the induction and possible role of activating transcription factor 3 (ATF3) in the corpus luteum. Postpubertal cattle were treated at midcycle with prostaglandin F2α(PGF) for 0–4 hours. Luteal tissue was processed for immunohistochemistry, in situ hybridization, and isolation of protein and RNA. Ovaries were also collected from midluteal phase and first-trimester pregnant cows. Luteal cells were prepared and sorted by centrifugal elutriation to obtain purified small (SLCs) and large luteal cells (LLCs). Real-time PCR and in situ hybridization showed that ATF3 mRNA increased within 1 hour of PGF treatment in vivo. Western blot and immunohistochemistry demonstrated …

American Society Of Parasitologists Newsletter, V. 35, No. 3, Winter 2013, Scott Lyell Gardner

American Society of Parasitologists: Newsletter

An issue of the American Society of Parasitologists' quarterly newsletter, also called the Journal of Parasitology Newsletter.