The movement behavior and reproductive ecology of western corn rootworm beetles (coleoptera: chrysomeliae) in Bt cornfields with structured and seed blend refuges

In the United States, western corn rootworm (Coleoptera: Chrysomelidae; Diabrotica virgifera virgifera LeConte) larvae have been managed using transgenic Bt (Bacillus thuringiensis Berliner) corn hybrids expressing insecticidal Cry proteins since 2003. To slow the evolution of resistance to Cry proteins, the Environmental Protection Agency mandated an insect resistance management (IRM) plan requiring the planting of non-Bt refuges as structured blocks or randomly distributed (seed blends) within Bt cornfields. Refuges allow susceptible larvae to develop without exposure to Cry proteins expressed elsewhere in the field. The modest populations of susceptible beetles from the refuge are expected to disperse across cornfields and mate with most of the rare, potentially resistant, beetles that survived Bt exposure. These “mixed-matings” are expected to produce heterozygous Bt susceptible offspring, delaying resistance because few resistant individuals will have opportunities to mate and produce homozygous Bt resistant offspring. Because the efficacy of the rootworm refuge strategy relies heavily on western corn rootworm movement and mating behavior, it is important to understand these behaviors in Bt cornfields. This dissertation presents data on daily movement within Bt cornfields and details of western corn rootworm mating relevant to resistance management. The spatial and temporal distribution of beetle mating activity and movement were measured in four refuge treatments 1) 20% structured refuge, 2) 5% structured refuge, 3) 5% seed blend refuge and 4) 0% refuge from 2010 to 2012. By testing beetle gut contents for the presence of specific Cry proteins and comparing them to the Cry proteins expressed by plants at their collection site, recent movement could be detected. These findings are presented in Chapters 2 and 3 of this dissertation. In Chapter 2, gut content analysis revealed that 8.5% of mating pairs were mixed-matings: they included a beetle that moved between refuge and Bt corn prior to mating. Most mixed-matings occurred in refuge corn, meaning that most resulted from an individual traveling from Bt to refuge corn before it mated. Dissection of mating females confirmed that most mated while they were newly emerged and that at least 4.5% of females mated more than once in short succession or more than a week after their initial mating. Chapter 3 of this dissertation revealed that the daily proportion of beetles moving between refuge and Bt corn was 17 to 25% collected during the vegetative period but dropped off dramatically to 3 to 10% during the pollination and post-pollination periods. When beetles moved within cornfields, they traveled at a rate of 26 to 31 m/day. In Chapter 4, the effect of high and low beetle density with three different M:F sex ratios (1:3, 1:1 and 3:1) on mating frequency was evaluated. Sex ratio significantly influenced mating regardless of density. More matings per female were recorded in male skewed treatments and more matings by males were recorded in female skewed treatments. Female dissections revealed that matings occurred throughout the five day experiment. Chapter 5 describes a sperm precedence study, in which females were given the opportunity to mate with a new male each day and paternity was assessed for family groups of egg batches as well as the female beetle and her two mates using microsatellite genotyping. Of the females in the study, 8.5% of females accepted a second mate and the mean interval between the first and second mating was 7.5 days. Genotyping results were inconclusive. The assumptions of the high-dose refuge strategy are poorly matched to the reality of western corn rootworm biology. Structured refuges do not facilitate movement and mating patterns that favor production of heterozygous susceptible offspring. A seed blend generated a more even distribution of beetles and mating activity; yet, detailed mating analyses suggest seed blends may not promote more desirable mixed-matings than structured refuges

Landslides on Ceres: Diversity and Geologic Context.

Landslides are among the most widespread geologic features on Ceres. Using data from Dawn's Framing Camera, landslides were previously classified based upon geomorphologic characteristics into one of three archetypal categories, Type 1(T1), Type 2 (T2), and Type 3 (T3). Due to their geologic context, variation in age, and physical characteristics, most landslides on Ceres are, however, intermediate in their morphology and physical properties between the archetypes of each landslide class. Here we describe the varied morphology of individual intermediate landslides, identify geologic controls that contribute to this variation, and provide first-order quantification of the physical properties of the continuum of Ceres's surface flows. These intermediate flows appear in varied settings and show a range of characteristics, including those found at contacts between craters, those having multiple trunks or lobes; showing characteristics of both T2 and T3 landslides; material slumping on crater rims; very small, ejecta-like flows; and those appearing inside of catenae. We suggest that while their morphologies can vary, the distribution and mechanical properties of intermediate landslides do not differ significantly from that of archetypal landslides, confirming a link between landslides and subsurface ice. We also find that most intermediate landslides are similar to Type 2 landslides and formed by shallow failure. Clusters of these features suggest ice enhancement near Juling, Kupalo and Urvara craters. Since the majority of Ceres's landslides fall in the intermediate landslide category, placing their attributes in context contributes to a better understanding of Ceres's shallow subsurface and the nature of ground ice

APOL1 risk alleles are associated with exaggerated age-related changes in glomerular number and volume in African-American adults: an autopsy study

APOL1 genetic variants contribute to kidney disease in African Americans. We assessed correlations between APOL1 profiles and renal histological features in subjects without renal disease. Glomerular number (N-glom,) and mean glomerular volume (V-glom,) were measured by the dissector/fractionator method in kidneys of African-American and non-African-American adults without renal disease, undergoing autopsies in Jackson, Mississippi. APOL1 risk alleles were genotyped and the kidney findings were evaluated in the context of those profiles. The proportions of African Americans with none, one, and two APOL1 risk alleles were 38%, 43%, and 19%, respectively; 38% of African Americans had G1 allele variants and 31% of African Americans had G2 allele variants. Only APOL1-positive African Americans had significant reductions in N-glom and increases in V-glom with increasing age. Regression analysis predicted an annual average loss of 8834 (P=0.03, sex adjusted) glomeruli per single kidney over the first 38 years of adult life in African Americans with two risk alleles. Body mass index above the group medians, but below the obesity definition of >= 30 kg/m(2), enhanced the expression of age-related changes in N-glom in African Americans with either one or two APOL1 risk alleles. These findings indicate that APOL1 risk alleles are associated with exaggerated age-related nephron loss, probably decaying from a larger pool of smaller glomeruli in early adult life, along with enlargement of the remaining glomeruli. These phenomena might mark mechanisms of accentuated susceptibility to kidney disease in APOL1-positive African Americans

WISE-2005: prolongation of left ventricular pre-ejection period with 56 days head-down bed rest in women

This study tested the hypothesis that prolonged physical deconditioning affects the coupling of left ventricular depolarization to its ejection (the pre-ejection period, PEPi) and that this effect is minimized by exercise countermeasures. Following assignment to non-exercise (Control) and exercise groups (Exercise), 14 females performed 56 days of continuous head-down tilt bed rest. Measurements of the electrocardiogram (ECG) and stroke volume (Doppler ultrasound) during supine rest were obtained at baseline prior to (Pre) and after (Post) the head-down tilt bed rest (HDBR) period. Compared with Pre, the PEPi was increased following head-down tilt bed rest (main effect, P \u3c 0.005). This effect was most dominant in the Control group [Pre = 0.038 ± 0.06 s (s.d.) versus Post = 0.054 ± 0.011 s; P \u3c 0.001]. In the Exercise group, PEPi was 0.032 ± 0.005 s Pre and 0.038 ± 0.018 s Post; P= 0.08. Neither the QRS interval nor cardiac afterload was modified by head-down tilt bed rest in Control or Exercise groups. Low-dose isoprenaline infusion reversed the head-down tilt bed rest-induced delay in the PEPi. These results suggest that head-down tilt bed rest leads to a delayed onset of systolic ejection following left ventricular depolarization in a manner that is affected little by the exercise countermeasure but is related to Β-adrenergic pathways. The delayed onset of systole following head-down tilt bed rest appears to be related to mechanism(s) affecting contraction of the left ventricle rather than its depolarization. © 2010 The Authors. Journal compilation © 2010 The Physiological Society

Sustainable Management of Water Resources

The Dawn spacecraft arrived at dwarf planet Ceres in spring 2015 and imaged its surface from four successively lower polar orbits at ground sampling dimensions between ∼1.3 km/px and ∼35 m/px. To understand the geological history of Ceres a mapping campaign was initiated to produce a set of 15 quadrangle-based geological maps using the highest-resolution Framing Camera imagery. Here we present the geological map of the Ac-10 Rongo Quadrangle, which is located at the equator encompassing the region from 22°N to 22°S and 288° to 360°E. The total relief within the quadrangle is 11.1 km with altitudes ranging from about −7.3 km to +3.8 km. We identified nine geological units based on surface morphology and surface textural characteristics. The dominant and most widespread unit is the cratered terrain (crt) representing ancient reworked crustal material. Its consistent formation age across the quadrangle is 1.8 Ga. Two edifices (unit th), Ahuna Mons and an unnamed tholus within Begbalel Crater, are interpreted to be of (cryo)volcanic origin. The southwest portion of the quadrangle is dominated by ejecta material (Ye) emplaced during the formation of the 260-km diameter Yalode impact basin at about 580 Ma. Rayed crater ejecta material (cr) is dominant in the eastern part of the quadrangle but also occurs in isolated patches up to a distance of 455 km from the 34 km diameter source crater Haulani. The remaining five geological units also represent impact crater materials: degraded rim (crdeg), bright crater (cb), hummocky floor (cfh), talus (ta), and crater (c) materials. Widespread Yalode and Haulani ejecta materials can potentially be utilised as stratigraphic markers. Therefore, it is essential to consistently map their full areal extent and to date their formations using impact crater statistics

Million-fold sensitivity enhancement in proteopathic seed amplification assays for biospecimens by Hofmeister ion comparisons

Recent work with prion diseases and synucleinopathies indicates that accurate diagnostic methods for protein-folding diseases can be based on the ultrasensitive, amplified measurement of pathological aggregates in biospecimens. A better understanding of the physicochemical factors that control the seeded polymerization of such aggregates, and their amplification in vitro, should allow improvements in existing assay platforms, as well as the development of new assays for other proteopathic aggregates. Here, we systematically investigated the effects of the ionic environment on the polymerization of tau, α-synuclein, and the prion protein (PrP) induced by aggregates in biospecimens. We screened salts of the Hofmeister series, a relative ordering of strongly and weakly hydrated salts that tend to precipitate or solubilize proteins. We found that sensitivities of tau-based assays for Alzheimer’s seeds and PrP-based assays for prions were best in weakly hydrated anions. In contrast, we saw an inverse trend with different tau-based assays, improving detection sensitivity for progressive supranuclear palsy seeds by ≈106. Hofmeister analysis also improved detection of sporadic Creutzfeldt–Jakob disease prions in human nasal brushings and chronic wasting disease prions in deer-ear homogenates. Our results demonstrate strong and divergent influences of ionic environments on the amplification and detection of proteopathic seeds as biomarkers for protein-folding diseases