Inheritance, fitness costs, and potential mechanisms of resistance for western corn rootworm larvae surviving Bt corn

The western corn rootworm, Diabrotica virgifera virgifera LeConte, has developed resistance to most control tactics used to manage it. Transgenic corn varieties that express insecticidal proteins from the bacterium Bacillus thuringiensis Berliner (Bt), cause mortality to target pests when ingested. In an attempt to delay resistance formation to these Bt products, the Environmental Protection Agency mandates the development of an insect resistance management program prior to registration for commercial sale. Despite plans to delay resistance being in place, resistance has developed in the field for both Cry3Bb1 and mCry3A-expressing hybrids. Resistance to these products could be due to physiological adaptations or through behavioral avoidance of the toxin in the plant. For the first portion of this work, we investigated a behavioral avoidance hypothesis for resistance. We hypothesized that later hatching western corn rootworm larvae could utilize previous feeding damage on Bt corn roots by early hatching larvae as an entry point into the root cortex containing lower levels of the Bt protein. Field and greenhouse tests involving infestation staggering to facilitate previous feeding damage did not support our hypothesis and did not indicate any effect of previous root feeding on the ability of this pest to establish on Bt plants and cause damage. We also evaluated resistance dynamics in the western corn rootworm in response to the most recent Bt protein commercialized for rootworm management, eCry3.1Ab. For one experiment, an eCry3.1Ab-selected and a paired control western corn rootworm colony were utilized to determine the potential fitness costs associated with eCry3.1Ab resistance. Adult longevity, egg viability, and larval development time results indicated a lack of fitness costs associated with eCry3.1Ab resistance in the western corn rootworm. Reciprocally crossed colonies of the eCry3.1Ab-selected and control colonies were created in order to evaluate whether the resistance trait to eCry3.1Ab was recessive, dominant, or something in between. Each reciprocal cross and their parent colonies were evaluated in diet toxicity and plant assays. Results indicated that the eCry3.1Ab resistance trait we selected for under laboratory conditions is dominantly inherited

Reverberation Mapping of the Dusty Torus in Active Galactic Nuclei

The Dusty Torus is a structure that is believed to exist in Active Galactic Nuclei. The Torus is physically too small to be spatially resolved, so Reverberation Mapping can be performed in order to replace spatial resolution with temporal resolution, yielding observations that can unravel the mystery of the Dusty Torus. One of the unknowns about the Torus is how the dust is distributed. The two competing theories are that either the dust resides in discrete clouds or that there is a solid wall of dust. This thesis presents the results of a year long observation program, starting in August 2011, that surveyed 12 Active Galactic Nuclei. Their fluxes were measured in two wavelengths: 3.6 and 4.5 µm. These two light curves were cross correlated with each other in a process called Flux Redistribution/Random Subset Selection in order to measure the lag in the signal between them. If there are discrete clouds of dust, the interchannel lag should be much smaller than the lag between the continuum and the 3.6 µm emissions. If there is a solid wall of dust, then the lag should be either as long or longer than the lag behind the continuum. Only one of the Active Galactic Nuclei, NGC 6418, had a measurable time lag, which was 12.3 +2.3 −1.9 days. This result, paired with estimates of the lag between the AGN continuum and the 3.6 µm emissions, is consistent with the discrete clouds theory

Genetic networks controlling retinal injury.

PURPOSE: The present study defines genomic loci underlying coordinate changes in gene expression following retinal injury. METHODS: A group of acute phase genes expressed in diverse nervous system tissues was defined by combining microarray results from injury studies from rat retina, brain, and spinal cord. Genomic loci regulating the brain expression of acute phase genes were identified using a panel of BXD recombinant inbred (RI) mouse strains. Candidate upstream regulators within a locus were defined using single nucleotide polymorphism databases and promoter motif databases. RESULTS: The acute phase response of rat retina, brain, and spinal cord was dominated by transcription factors. Three genomic loci control transcript expression of acute phase genes in brains of BXD RI mouse strains. One locus was identified on chromosome 12 and was highly correlated with the expression of classic acute phase genes. Within the locus we identified the inhibitor of DNA binding 2 (Id2) as a candidate upstream regulator. Id2 was upregulated as an acute phase transcript in injury models of rat retina, brain, and spinal cord. CONCLUSIONS: We defined a group of transcriptional changes associated with the retinal acute injury response. Using genetic linkage analysis of natural transcript variation, we identified regulatory loci and candidate regulators that control transcript levels of acute phase genes

Frequency and Distribution of Extended Diapause in Nebraska Populations of \u3ci\u3eDiabrotica barberi\u3c/i\u3e (Coleoptera: Chrysomelidae)

The frequency of extended diapause in populations of the northern corn rootworm, Diabrotica barberi Smith & Lawrence (Coleoptera: Chrysomelidae), was measured in eastern Nebraska. Adult collections were made during late summer in 2008 and 2009 from eight sites each year (seven sites were consistent over years). Eggs were obtained from 12 to 20 females per site and were held on moist soil under appropriate temperature profiles to facilitate egg survival, diapause development, and diapause termination. Percentage egg hatch was recorded after the first and second year for the 2008 and 2009 collections. Additional extended diapause expression was estimated for the 2008 and 2009 collections by counting remaining live eggs after the second-year egg hatch was completed. These data also were used to estimate each site’s maximum egg viability. Results collectively indicate that the extended diapause trait was present in all eastern Nebraska populations; however, significant variation in the frequency of extended diapause was observed within and among D. barberi populations (first-year mean percentage egg hatch range: 2008 collections: 4.5–38.6%; 2009 collections: 10.7–42.5%). Geographically, the highest incidence of extended diapause was found along a north-south transect in eastern counties of Nebraska that parallels the Missouri River. In general, the frequency of extended diapause was lower in sites found west of the north-south transect. This study contributes to the knowledge base needed to develop appropriate D. barberi management strategies in Nebraska. These data can be used to pinpoint areas of Nebraska that may have the greatest risk of economic injury in first-year corn (Zea mays L.) when D. barberi densities are high

Frequency and Distribution of Extended Diapause in Nebraska Populations of \u3ci\u3eDiabrotica barberi\u3c/i\u3e (Coleoptera: Chrysomelidae)

The frequency of extended diapause in populations of the northern corn rootworm, Diabrotica barberi Smith & Lawrence (Coleoptera: Chrysomelidae), was measured in eastern Nebraska. Adult collections were made during late summer in 2008 and 2009 from eight sites each year (seven sites were consistent over years). Eggs were obtained from 12 to 20 females per site and were held on moist soil under appropriate temperature profiles to facilitate egg survival, diapause development, and diapause termination. Percentage egg hatch was recorded after the first and second year for the 2008 and 2009 collections. Additional extended diapause expression was estimated for the 2008 and 2009 collections by counting remaining live eggs after the second-year egg hatch was completed. These data also were used to estimate each site’s maximum egg viability. Results collectively indicate that the extended diapause trait was present in all eastern Nebraska populations; however, significant variation in the frequency of extended diapause was observed within and among D. barberi populations (first-year mean percentage egg hatch range: 2008 collections: 4.5–38.6%; 2009 collections: 10.7–42.5%). Geographically, the highest incidence of extended diapause was found along a north-south transect in eastern counties of Nebraska that parallels the Missouri River. In general, the frequency of extended diapause was lower in sites found west of the north-south transect. This study contributes to the knowledge base needed to develop appropriate D. barberi management strategies in Nebraska. These data can be used to pinpoint areas of Nebraska that may have the greatest risk of economic injury in first-year corn (Zea mays L.) when D. barberi densities are high

Art and Technology: Reviving Van Gogh for a New Generation

Our world is ever-changing due to technology’s rapid progress; some changes have been beneficial while others have been detrimental. My Honors Thesis focuses on exploring whether such progress has had a positive or negative impact on the art world and its audiences. As such, the purpose of this paper is to illustrate the difference between direct observation of still works of art versus being able to be fully immersed in said works via projection technologies. Starting with a brief history of the artist Vincent Van Gogh, as well as an examination of the Impressionist movement in Paris in the 19th c., will lead me to an analysis of direct observation of his paintings, which was how works during his lifetime were meant to be experienced. I will then take my experience of the Beyond Van Gogh exhibition and compare the two. While each method of viewing art has its merits, the ability to emotionally connect with Van Gogh’s works is magnified by the immersive format, and I will show how these technologies have the power to revive history for a whole new generation of young artists.NASUNY BrockportHonors CollegeBAChase, Alisi

Effects of Cold Storage on Nondiapausing Eggs of the Western Corn Rootworm (Coleoptera: Chrysomelidae)

Western corn rootworm, Diabrotica virgifera virgifera LeConte, became much easier to research with the development of a nondiapausing rootworm strain. In the event that the eggs cannot be used immediately researchers have been known to delay egg hatch by storing the eggs at low temperatures. It is not well known how this technique could affect egg hatch or larval development, which could alter the results of an experiment. To test for this nondiapausing eggs of the western corn rootworm were stored at low temperatures to test for potential negative effects on hatch and larval development. Eggs were stored in either soil or agar and placed in refrigerators set to 4 or 8.5°C. Nondiapausing eggs were exposed to the cold for 1, 2, or 4 wk and then placed in a chamber set to 25°C. Eggs were then tested for average hatch percentage in Petri dishes and average larval recovery from containers with seedling corn. Results showed a significant reduction in percent hatch for eggs stored at 4°C for 4 wk. Larval recovery was significantly reduced in eggs stored for 4 wk at both 4 and 8.5°C. Within the treatments tested, egg storage for less than 4 wk in soil at 8.5°C provided the best hatch and larval recovery. Researchers wishing to store eggs may use these results to improve their rearing or testing of western corn rootworm