Twin studies demonstrate significant environmental influences and a lack of genetic effects on disordered eating before puberty in girls. However, genetic factors could act indirectly through passive gene–environment correlations (rGE; correlations between parents’ genes and an environment shaped by those genes) that inflate environmental (but not genetic) estimates. The only study to explore passive rGE did not find significant effects, but the full range of parental phenotypes (e.g., internalizing symptoms) that could impact daughters’ disordered eating was not examined. We addressed this gap by exploring whether parents’ internalizing symptoms (e.g., anxiety, depressive symptoms) contribute to daughters’ eating pathology through passive rGE. Participants were female twin pairs (aged 8–14 years; M = 10.44) in pre-early puberty and their biological parents (n = 279 families) from the Michigan State University Twin Registry. Nuclear twin family models explored passive rGE for parents’ internalizing traits/symptoms and twins’ overall eating disorder symptoms. No evidence for passive rGE was found. Instead, environmental factors that create similarities between co-twins (but not with their parents) and unique environmental factors were important. In pre-early puberty, genetic factors do not influence daughters’ disordered eating, even indirectly through passive rGE. Future research should explore sibling-specific and unique environmental factors during this critical developmental period.

OBJECTIVES/SPECIFIC AIMS: Objectives and goals of this study are to (i) determine whether IBS-D patients randomized to either rifaximin or low FODMAP diet show improvement in IBS-related symptoms; and (2) identify using longitudinal analyses how SIBO status and fecal microbiota features associate with response to either rifaximin or low FODMAP dietary intervention. METHODS/STUDY POPULATION: 42 patients ≥ 18 years of age who meet Rome IV criteria for IBS-D will be randomized to receive either rifaximin or low FODMAP diet intervention. The primary outcome will be the proportion of responders to intervention which is defined as ≥ 30% reduction in mean daily abdominal pain or bloating by visual analog scale compared with baseline. Exclusion criteria will include: (a) history of microscopic colitis, inflammatory bowel disease, celiac disease, or other organic disease that could explain symptoms, (b) prior gastrointestinal surgery, other than appendectomy or cholecystectomy > 6 months prior to study initiation, (c) prior use of rifaximin or formal dietary interventions for IBS-D, (d) use of antibiotics within the past 3 months, or (e) use of probiotics within 1 month of study entry. Glucose hydrogen breath tests will be performed at the beginning and end of the trial to evaluate for SIBO. Fecal samples will be collected at 0, 2, and 6 weeks to determine changes in fecal microbial composition and structure. RESULTS/ANTICIPATED RESULTS: This study seeks to examine whether longitudinal analyses of small intestinal and colonic microbiota can subtype IBS-D subjects into clinically relevant phenotypes. A total of 18 subjects have been enrolled into the study. Clinical variables, hydrogen breath test results, and fecal microbiota data are being collected for ongoing analysis. DISCUSSION/SIGNIFICANCE OF IMPACT: Results from this study may help move treatment of IBS from a purely symptom based approach to a more individualized approach by stratifying IBS-D patients into distinct clinical phenotypes which are amenable to targeted therapeutic approaches.

Placing hydrilla (Hydrilla verticillata Royle) in 2.7 and 5.4 μM solutions of carbon-14-labeled endothali [7-ox = abicyclo(2,2,1)heptane-2,3-dicarboxylic acid] under controlled conditions resulted in a sigmoid-shaped uptake curve for both herbicide concentrations. Apical sections of hydrilla, which included the apical bud, absorbed greater amounts of endothall-14C than sections excised from the center of the plant below the apical bud. Low concentrations of copper as copper sulfate pentahydrate solutions of 0.4 and 2.0 μM in combination with endothall-14C increased the amount of radioactivity found in hydrilla, but copper concentrations of 4.0, 8.0, and 16.0 μM inhibited endothall-14C uptake. The greatest uptake by hydrilla in 5.4 and 2.7 μM solutions of endothall-14C exposed to temperatures of 10, 20, and 30 C occurred in the 20 and 30 C solutions, respectively. Endothall-14C uptake was studied under light intensities of 0, 540, 5400, and 21,500 lux. Uptake of radioactivity from 2.7 and 5.4 μM solutions of endothall-14C was greatest at 540 and 21,500 lux, respectively.

Flumioxazin has recently (2010) been registered for aquatic use for control of hydrilla and other noxious invasive aquatic plant species. Due to the rapid degradation of flumioxazin, especially in high pH water, some hydrilla research trials have produced less than desirable results with rapid plant regrowth. Therefore, laboratory experiments were conducted to evaluate the influence of pH on flumioxazin's effect on photosynthesis. Flumioxazin applied at concentrations ≥ 200 µg ai L−1 in high (9.0) pH water and ≥ 100 µg L−1 in low (6.0) pH water required 68 to 123 h to reduce photosynthesis by 50% (ET50). The effect of 400 µg L−1 flumioxazin on photosynthesis of apical hydrilla tips was also compared at low (20 µmol m−2 s−1), medium (170 µmol m−2 s−1), and high (400 µmol m−2 s−1) light levels at pH 9.0. Low light–treated tips were still photosynthetic at approximately 73% of the nontreated control plants 168 h after treatment. Low light–treated hydrilla required an estimated 303 h to achieve a 50% reduction in photosynthesis, while high light plants only required 99 h. Chlorophyll content of hydrilla was reduced as flumioxazin concentration was increased from 100 to 1,600 µg L−1. These data indicate that flumioxazin activity on hydrilla photosynthesis is influenced by herbicide concentration, water pH, and light intensity.

The development of fluridone resistance by hydrilla has significantly impacted hydrilla management, and research is ongoing to develop alternate herbicides for effective hydrilla control. We determined the potential cross-resistance in fluridone-resistant hydrilla to other bleaching herbicides norflurazon, mesotrione, and topramezone-methyl. Phytoene, β-carotene, and chlorophyll contents as a function of hydrilla biotype and herbicide treatment were evaluated. Hydrilla shoot tips were collected from fluridone-susceptible (S) and -resistant (R) biotypes and exposed to 5, 25, 50, 75, and 100 µg L−1 of herbicide. The susceptible biotype showed an increase in phytoene and a decrease in β-carotene and chlorophyll contents when treated with 5 µg L−1 fluridone, whereas higher doses of fluridone were required to affect these pigments in the resistant biotype. There was no difference in response by S and R biotypes to mesotrione and topramezone-methyl, with both biotypes showing significant affects on pigment contents at 5 µg L−1. Higher doses of norflurazon were required to affect these pigments in the R compared to the S biotype. The S biotype had EC50 values of 11.7, 12.2, and 4.7 µg L−1, whereas the R biotype had EC50 values of 56.6, 41.1, and 41.7 µg L−1 fluridone for phytoene, β-carotene, and chlorophyll contents, respectively. There was no difference in EC50 for phytoene, β-carotene, and chlorophyll values between the hydrilla biotypes for mesotrione and topramezone-methyl herbicides. In fluridone-susceptible and -resistant hydrilla biotypes, EC50 values for phytoene, β-carotene, and chlorophyll were 12.4 to 11.8, 10.2 to 13.2, and 3.1 to 4.6 µg L−1 mesotrione and 12.6 to 13.5, 13.3 to 11.9, and 4.6 to 5.7 µg L−1 topramezone-methyl, respectively. For norflurazon, S and R biotypes had EC50 values of 33.1, 45.4, and 40.6 µg L−1 and 84.6, 81.0, and 92.7 µg L−1 for phytoene, β-carotene, and chlorophyll, respectively. These studies confirmed negative cross-resistance of fluridone-resistant hydrilla to mesotrione and topramezone-methyl and a positive cross-resistance to norflurazon.

Bodies of water that are treated with herbicides for aquatic weed control are often used as a source of irrigation water by landowners near the water body, but there is little information regarding the effects of experimental aquatic herbicides on common garden plants. Therefore, the goal of these experiments was to identify phytotoxicity of four herbicides on vegetables frequently cultivated by home gardeners. Sweet pepper, zucchini, tomato, and bush bean were irrigated with water containing bispyribac-sodium, quinclorac, topramezone, and trifloxysulfuron-sodium to identify the herbicide concentrations that damage these garden vegetables. Experiments were conducted during 2009 and repeated in 2010. Plants were irrigated four times during an 11-d period with the equivalent of 1.27 cm of treated water during each irrigation, then irrigated with well water until they were harvested 41 d after the first herbicide treatment. Values of the concentration of herbicide expected to reduce treated plants by 10% compared with control plants (EC10) were calculated from components of nonlinear regression. Analysis of visual quality and dry weight data revealed that bush bean was the most sensitive of the vegetable plants to bispyribac-sodium, trifloxysulfuron-sodium, and topramezone, whereas the species most sensitive to quinclorac was zucchini. Exposure of bush bean to 7.1, 0.9, and 1.2 parts per billion (ppb) of bispyribac-sodium, trifloxysulfuron-sodium, and topramezone, respectively, would be expected to cause 10% reductions compared with control plants, whereas exposure of zucchini to as little as 11.0 ppb of quinclorac would be expected to cause a 10% reduction in dry weight.

Hydrilla is one of the most serious aquatic weed problems in the United States, and fluridone is the only U.S. Environment Protection Agency (USEPA)–approved herbicide that provides relatively long-term systemic control. Recently, hydrilla biotypes with varying levels of fluridone resistance have been documented in Florida. Fluridone-susceptible (S) and several fluridone-resistant (R1 to R5) hydrilla biotypes varying in resistance levels were maintained in 950-L tanks under ambient sunlight and day-length conditions. To correlate varying levels of fluridone resistance to ploidy in hydrilla, flow cytometric analysis was performed. Differential ploidy levels (diploid, 2n = 2x = 16; triploid, 2n = 3x = 24; and tetraploid, 2n = 4x = 32) were reported among different hydrilla biotypes, plants within each biotype, and within shoot tissues of the same plant. Triploid plants were predominant in all biotypes. Diploid plants were observed in all hydrilla biotypes except the susceptible hydrilla (S). Plants with tetraploidy were rare within biotypes. The diploid, triploid, and tetraploid plants had nuclear DNA contents of 2.43 to 2.73 pg, 3.44 to 3.71 pg, and 4.64 to 4.90 pg, respectively, and no differences were observed among plants with same ploidy for nuclear DNA content in different hydrilla biotypes. Endoreduplication patterns were observed in diploid plants of R1 and R3 biotypes. However, no plant with higher ploidy levels (triploid or tetraploid) in any hydrilla biotypes showed endoreduplication.

Landoltia was collected and cultured from a canal in Lake County, Florida, where diquat was used repeatedly during the past 20–30 yr for duckweed control. Recent applications of diquat failed to provide adequate control of duckweed, and a new commercial formulation of diquat was suspected. The new formulation was not the cause of reduced efficacy. Static exposures (48 h) to various concentrations of diquat were used to compare the susceptibility of the Lake County landoltia accession to one never exposed to diquat. These static tests indicated that landoltia, from a population with no prior history of herbicide treatment, was extremely susceptible to diquat. The accession from Lake County, FL had developed resistance to diquat, and was also cross resistant to paraquat. The resistance factor was 50 for diquat and 29 for paraquat. The Lake County accession also exhibited reduced ion leakage after diquat exposure under light and dark conditions. This suggests the resistance mechanism to the bipyridylium herbicides in landoltia is independent of photosynthetic electron transport. This research documents the first aquatic plant species that has developed resistance to the bipyridylium herbicides.

The effects of flumioxazin in irrigation water were evaluated on four row crop species (corn, cotton, soybean, and wheat) and three ornamental species (begonia, impatiens, and snapdragon). Plants were overhead irrigated one time with flumioxazin at concentrations of 0, 10, 25, 50, 100, 200, 400, 800, 1,600, and 3,200 µg ai/L in water equivalent to 1.27 cm. Ornamental plant tolerances on the basis of a 10% reduction in dry weight (effective concentration 10 [EC10]) were as follows: impatiens (40) < begonia (103) < snapdragon (7,024). The EC10 values of flumioxazin on the basis of dry weight values for row crop species were wheat (35) < corn experiment 1 (53) < cotton (106) < corn experiment 2 (181) < soybean (193). EC10 values for plant height were similar to values for plant dry weight for ornamental and crop species. Snapdragon was the only plant evaluated that was mature at the time of treatment; consequently, all other species were moderately to highly sensitive to irrigation water containing flumioxazin. These data show that flumioxazin can injure and kill immature ornamental and crop species within the potential maximum concentration of 400 µg/L; however, the very short half-life of this herbicide in water with pH 7.0 to 9.0 (ca. 16 h to 17 min) could result in less injury than suggested in this study.

Cabomba is a submersed aquatic plant native to the southeastern United States that is commonly sold worldwide through the aquarium trade. While infrequently managed in its native range, cabomba has recently been reported as invasive and tolerant to management efforts in the northern areas of the United States and in other countries. Invasive populations of cabomba are characterized by a phenotype that is bright green. In contrast, cabomba native to the southeastern United States is characterized by a red phenotype, while plants sold through the aquarium trade have intermediate characteristics of both the green and red phenotypes. The response of the three cabomba phenotypes to selected herbicides was evaluated by measuring photosynthetic response over the course of a static 144-hr exposure. Plants were exposed to the maximum recommended use-rates of 2,4-D, carfentrazone, copper, diquat, endothall (amine and dipotasium salt formulation), flumioxazin, quinclorac, triclopyr, and a combination of diquat and copper. A submersed plant species known to be sensitive to each of these herbicides was also included to compare photosynthetic response of the cabomba to a susceptible plant. The photosynthetic response of the red and green phenotypes differed following exposure to carfentrazone, diquat, 2,4-D, triclopyr, and flumioxazin. Diquat, diquat plus copper, endothall (amine salt), and flumioxazin were the only products that resulted in a greater than 50% reduction of photosynthesis in all three phenotypes of cabomba. A second experiment was conducted where all three phenotypes of cabomba were exposed to these four herbicides for 24 hr, and photosynthesis was evaluated. Following the 24-hr exposure, results further documented distinct response differences between the green and red phenotypes, with the green phenotype demonstrating a reduced sensitivity to the herbicides evaluated. Results demonstrate clear phenotypic differences in response to herbicide treatments and lack of susceptibility of cabomba to most herbicides.

Hydrilla is one of the most serious aquatic weed problems in the United States, and fluridone is the only U.S. Environment Protection Agency (USEPA)–approved herbicide that provides relatively long-term systemic control. Recently, hydrilla biotypes with varying levels of fluridone resistance have been documented in Florida. Several biotypes of hydrilla varying in resistance levels were maintained in 950-L tanks under ambient sunlight and day-length conditions from September 2004 to September 2005 in absence of fluridone. Phenotypic measurements were performed during this 1-yr period to monitor differences in growth and reproductive physiology. All fluridone-resistant biotypes (except R3) were growing at the same rate or greater than the susceptible hydrilla. These data suggested that there are no deleterious effects on growth and reproductive physiology because of development of fluridone resistance. Aggressive spread of fluridone-resistant dioecious hydrilla in aquatic ecosystems can severely affect hydrilla management and, consequently, cause substantial and long-lasting ecological and economic problems throughout the southern United States.

Hydrilla is one of the most serious aquatic weed problems in the United States, and fluridone is the only U.S. Environment Protection Agency (USEPA)–approved herbicide that provides relatively long-term systemic control. Recently, hydrilla biotypes with varying levels of fluridone resistance have been documented in Florida. One susceptible and five fluridone-resistant biotypes of hydrilla varying in resistance levels were maintained in 950-L tanks under ambient sunlight and day-length conditions from September 2004 to September 2005 in absence of fluridone. Because fluridone is an inhibitor of the enzyme phytoene desaturase (PDS), the gene for PDS (pds) was cloned from fluridone-susceptible and -resistant hydrilla biotypes. Somatic mutations in amino acid 304 of hydrilla PDS are known to confer herbicide resistance. We determined pds sequence from these hydrilla biotypes at planting and 12-mo after planting. Two independent mutations at the arginine 304 codon of pds were found in the resistant hydrilla plants. The codon usage for arginine 304 is CGT, and a single point mutation yielding either serine (AGT) or histidine (CAT) was identified in different resistant hydrilla biotypes. There were no differences at codon 304 in the PDS protein of any hydrilla biotype 12-mo after planting. Several other mutations were also found in resistant pds alleles, though their possible role in herbicide resistance is unclear.

We have carried out a systematic study of the effects of irradiation on the electronic and optical properties of InGaN alloys over the entire composition range. High energy electrons, protons, and 4He+ were used to produce displacement damage doses (Dd) spanning over five orders of magnitude. The free electron concentrations in InN and In-rich InGaN increase with Dd and finally saturate after a sufficiently high Dd. The saturation of carrier density is attributed to the formation of native donors and the Fermi level pinning at the Fermi Stabilization Energy (EFS), as predicted by the amphoteric native defect model. Electrochemical capacitance-voltage (ECV) measurements reveal a surface electron accumulation whose concentration is determined by pinning at EFS.

High-energy particle irradiation has been used to control the free electron concentration and electron mobility in InN by introducing native point defects that act as donors. A direct comparison between theoretical calculations and the experimental electron mobility suggests that scattering by triply-charged donor defects limits the mobility in irradiated samples across the entire range of electron concentrations studied. Thermal annealing of irradiated films in the temperature range 425°C to 475°C results in large increases in the electron mobility that approach the values predicted for singly-ionized donor defect scattering. It is suggested that the radiation-induced donor defects are stable, singly-charged nitrogen vacancies, and triply-charged, relaxed indium vacancy complexes that are removed by the annealing.

The hydrostatic pressure dependence of the optical transitions in InN, In-rich In1-xGaxN (0 < x < 0.5) and In1-xAlxN (x = 0.25) alloys is studied using diamond anvil cells. The absorption edges and the photoluminescence peaks shift to higher energy with pressure. The pressure coefficient of InN is determined to be 3.0±0.1 meV/kbar. Together with previous experimental results, our data suggest that the pressure coefficients of group-III nitride alloys have only a weak dependence on the alloy composition. Photoluminescence gives much smaller pressure coefficients, which is attributed to emission involving highly localized states. This indicates that photoluminescence might not be an accurate method to study the pressure dependence of the fundamental bandgaps of group III-nitrides.