29 research outputs found

    Grow them and we will come for the feast

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    Sustainable production of switchgrass and other bioenergy grasses will require eff ective pest management. Identifi cation of potential insect pests and detailed characterization of the plant-insect interaction will better enable us to address emergent insect pests in production fi elds. An added uncertainty is how manipulation of plants for improved quality (e.g. lower lignin) will aff ect plant resistance to insect herbivory. Plants can utilize different mechanisms to defend against chewing versus piercing-sucking insects; however, some basal plant responses appear to be shared across diverse biotic stressors. Th e range and modulation of these responses are beginning to be addressed for several of the temperate, perennial, warm-season grasses that are designated as biomass crops. Other systems have demonstrated the need to become proactive in these studies. For instance, buff alograss, Buchloë dactyloides (Nuttall) Engelmann, was fi rst introduced as a low-maintenance turf species. However, a number of important insect pests were documented within a relatively short time frame.1,2 Similarly, several recent reports have been published for switchgrass (Panicum virgatum L.) and Miscanthus (Miscanthus x giganteus) that indicate the presence of insect pests in production fi elds, and the overall susceptibility of these species to insect herbivory.3-

    Mass production of volume phase holographic gratings for the VIRUS spectrograph array

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    The Visible Integral-field Replicable Unit Spectrograph (VIRUS) is a baseline array of 150 copies of a simple, fiber-fed integral field spectrograph that will be deployed on the Hobby-Eberly Telescope (HET). VIRUS is the first optical astronomical instrument to be replicated on an industrial scale, and represents a relatively inexpensive solution for carrying out large-area spectroscopic surveys, such as the HET Dark Energy Experiment (HETDEX). Each spectrograph contains a volume phase holographic (VPH) grating with a 138 mm diameter clear aperture as its dispersing element. The instrument utilizes the grating in first-order for 350-550 nm. Including witness samples, a suite of 170 VPH gratings has been mass produced for VIRUS. Here, we present the design of the VIRUS VPH gratings and a discussion of their mass production. We additionally present the design and functionality of a custom apparatus that has been used to rapidly test the first-order diffraction efficiency of the gratings for various discrete wavelengths within the VIRUS spectral range. This device has been used to perform both in-situ tests to monitor the effects of adjustments to the production prescription as well as to carry out the final acceptance tests of the gratings' diffraction efficiency. Finally, we present the as-built performance results for the entire suite of VPH gratings.Comment: 16 pages, 11 figures, 2 tables. To be published in Proc. SPIE, 2014, "Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation", 9151-53. The work presented in this article follows from arXiv:1207:448

    A Novel Approach to Improve the Estimation of a Diet Adherence Considering Seasonality and Short Term Variability – The NU-AGE Mediterranean Diet Experience

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    In this work we present a novel statistical approach to improve the assessment of the adherence to a 1-year nutritional intervention within the framework of the NU-AGE project. This was measured with a single adherence score based on 7-days food records, under limitations on the number of observations per subject and time frame of intervention. The results of the NU-AGE dietary intervention were summarized by variations of the NU-AGE index as described in the NU-AGE protocol. Food and nutrient intake of all participants was assessed by means of 7-days food records at recruitment and after 10 to 14 months of intervention (depending on the subject availability). Sixteen food groups and supplementations covering the dietary goals of the NU-AGE diet have been used to estimate the NU-AGE index before and after the intervention. The 7-days food record is a reliable tool to register food intakes, however, as with other tools used to assess lifestyle dietary compliance, it is affected by uncertainty in this estimation due to the possibility that the observed week is not fully representative of the entire intervention period. Also, due to logistic limitations, the effects of seasonality can never be completely removed. These variabilities, if not accounted for in the index estimation, will reduce the statistical power of the analyses. In this work we discuss a method to assess these uncertainties and thus improve the resulting NU-AGE index. The proposed method is based on Hierarchical Bayesian Models. This model explicitly includes country-specific averages of the NU-AGE index, index variation induced by the dietary intervention, and country based seasonality. This information is used to evaluate the NU-AGE index uncertainty and thus to estimate the “real” NU-AGE index for each subject, both before and after the intervention. These corrections reduce the possibility of misinterpreting measurement variability as real information, improving the power of the statistical tests that are performed with the resulting index. The results suggest that this method is able to reduce the short term and seasonal variability of the measured index in the context of multicenter dietary intervention trials. Using this method to estimate seasonality and variability would allow one to obtain better measurements from the subjects of a study, and be able to simplify the scheduling of diet assessments

    Transcriptional analysis of defense mechanisms in upland tetraploid switchgrass to greenbugs

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    Background: Aphid infestation of switchgrass (Panicum virgatum) has the potential to reduce yields and biomass quality. Although switchgrass-greenbug (Schizaphis graminum; GB) interactions have been studied at the whole plant level, little information is available on plant defense responses at the molecular level. Results: The global transcriptomic response of switchgrass cv Summer to GB was monitored by RNA-Seq in infested and control (uninfested) plants harvested at 5, 10, and 15 days after infestation (DAI). Differentially expressed genes (DEGs) in infested plants were analyzed relative to control uninfested plants at each time point. DEGs in GB-infested plants induced by 5-DAI included an upregulation of reactive burst oxidases and several cell wall receptors. Expression changes in genes linked to redox metabolism, cell wall structure, and hormone biosynthesis were also observed by 5- DAI. At 10-DAI, network analysis indicated a massive upregulation of defense-associated genes, including NAC, WRKY, and MYB classes of transcription factors and potential ancillary signaling molecules such as leucine aminopeptidases. Molecular evidence for loss of chloroplastic functions was also detected at this time point. Supporting these molecular changes, chlorophyll content was significantly decreased, and ROS levels were elevated in infested plants 10-DAI. Total peroxidase and laccase activities were elevated in infested plants at 10-DAI relative to control uninfested plants. The net result appeared to be a broad scale defensive response that led to an apparent reduction in C and N assimilation and a potential redirection of nutrients away from GB and towards the production of defensive compounds, such as pipecolic acid, chlorogenic acid, and trehalose by 10-DAI. By 15-DAI, evidence of recovery in primary metabolism was noted based on transcript abundances for genes associated with carbon, nitrogen, and nutrient assimilation. Conclusions: Extensive remodeling of the plant transcriptome and the production of ROS and several defensive metabolites in an upland switchgrass cultivar were observed in response to GB feeding. The early loss and apparent recovery in primary metabolism by 15-DAI would suggest that these transcriptional changes in later stages of GB infestation could underlie the recovery response categorized for this switchgrass cultivar. These results can be exploited to develop switchgrass lines with more durable resistance to GB and potentially other aphids

    Identifikasi Nilai-Nilai Cerita Wayang Beber Pacitan sebagai Media Pembelajaran Sejarah

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    Wayang Beber Pacitan merupakan hasil kearifan lokal atau local genius bangsa Indonesia dan menjadi local identity atau identitas budaya bangsa. Isinya mengenai kepahlawanan dan percintaan yang berpusat pada dua tokoh utama, yaitu raden Inu Kertapati atau Panji Asmarabangun, dan Dewi Sekartaji atau Galuh Candrakirana. Cerita dalam Wayang Beber Pacitan mempunyai folklor yang sarat dengan nilai-nilai simbolis yang masih relevan dengan masa sekarang. Penyebarluasan cerita Wayang Beber ini sangat penting untuk menjaga agar tidak punah dan mengajarkannya kepada generasi muda merupakan cara yang tepat. Salah satu media yang tepat adalah melalui Pembelajaran Sejarah.Pembelajaran sejarah haruslah mengembangkan tugas sebagai wahana “transmission of culture”. Fungsi didaktis Pembelajaran Sejarah dimana pengetahuan sejarah dimaksudkan agar generasi penerus bisa mengambil hikmah dari masa lalu selain itu juga mengambil pelajarannya. Sejarah sebagai sarana edukatif dan inspiratif memberikan nilai-nilai pendidikan bagi peserta didik yang sangat berguna dalam memberikan inspirasi kepada peserta didik. Nilai-nilai dalam cerita Wayang beber Pacitan dapat digunakan sebagai media Pembelajaran Sejarah, untuk memberikan pengalaman nyata yang dapat menumbuhkan kegiatan berusaha sendiri peserta didik. Oleh karena itu tulisan ini berusaha menguraikan nilai-nilai yang terkandung dalam cerita Wayang Beber sebagi media pembelajaran sejarah. Penulisan ini menggunakan metode deskriptif kualitatif

    Characterization of the Tolerance Response in the Soybean KS4202 to \u3ci\u3eAphis glycines\u3c/i\u3e Matsumura

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    Since the introduction of the soybean aphid, Aphis glycines Matsumura, to the soybean growing regions of the United States, the soybean aphid has caused considerable economic damage and yield loss to soybean growers. The objectives of this research were to evaluate selected genotypes for resistance to the soybean aphid and characterize transcriptional changes in response to aphid feeding to better understand the underlying tolerant mechanism(s) in KS4202 and genes contributing to its tolerance response. A field study (2009) was conducted to evaluate selected soybean genotypes during their reproductive stages for resistance to A. glycines. The economic injury level (EIL) was reached in all genotypes during the 2009-growing season. Most of the genotypes showed no significant differences in yield or yield parameters with some minor exceptions for a few yield parameters. For KS4202, the average seed weight and the average number of seeds per pod for aphid infested treatments were significantly lower than their respective non-infested control plants. The mean number of aphids was significantly higher for KS4202 when compared to the other genotypes and the average peak number of aphids for this genotype was almost 5 times the economic threshold. The second component of this research was to characterize transcriptional changes in response to aphid feeding to better understand the underlying tolerant mechanism(s) in KS4202 and genes contributing to the tolerance response. Comparing gene expression levels between infested and control plants for KS4202, over 550 genes had a higher expression level in response to aphid feeding, while, over 650 genes had a lower expression level in response to aphid feeding. For K03-4686 (susceptible), over 150 genes had a higher expression level in response to aphid feeding, whereas, over 750 genes had a lower expression level when comparing infested to control plants. This research will significantly add to the understanding of the mechanisms of soybean aphid tolerance in soybeans and allow for the continual development of improved soybeans varieties with soybean aphid resistance. Advisers: Tiffany Heng-Moss and Thomas E. Hun

    BIOCHEMICAL, PHYSIOLOGICAL, AND ANATOMICAL INSIGHTS INTO APHID-BIOENERGY SWITCHGRASS INTERACTIONS

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    Switchgrass, Panicum virgatum L., a perennial, warm-season grass native to North America, is a candidate for development as a bioenergy crop. Previously, warm-season grasses were considered to be relatively pest free in their native habitats. However, recent studies using the hemipteran family Aphididae have shown phloem-feeding insects can lead to significant injury in switchgrass. The objectives of this research were to: 1) gain physiological, biochemical, and anatomical insights into insect-bioenergy switchgrass interactions to determine potential insect resistance mechanisms among susceptible and resistant switchgrass genotypes; and 2) to generate and evaluate diverse segregating populations of switchgrass, both resistant and susceptible, to assess for insect herbivory. Recently, select aphids including greenbugs, Schizaphis graminum (Rondani), and yellow sugarcane aphids, Sipha flava (Forbes), have been identified as potential pests of switchgrass. However, limited research has been devoted to selecting insect-resistant switchgrasses and understanding the physiological responses of susceptible and resistant switchgrasses to aphid feeding. Using a series of photosynthesis studies, differences in photosynthetic activity were detected among the switchgrasses evaluated in response to aphid feeding. Overall, the lowland ecotype (Kanlow) assimilated carbon dioxide more efficiently than the upland ecotype (Summer) and the hybrid KxS when exposed to aphid herbivory. These observations suggest the antibiotic population, Kanlow, has mechanisms similar to those observed in tolerant plant systems where changes in photosynthetic rates occurred in response to aphid herbivory. Feeding by greenbugs and yellow sugarcane aphids on plants can elicit a number of stress-related responses. Our studies investigated the accumulation of reactive oxygen species (ROS) scavenging enzymes and defensive response genes in resistant and susceptible switchgrass populations using biochemical protocols along with gene expression studies. Genes of interest involving greenbug-switchgrass interactions were identified from previous Illumina® Solexa data, specifically RNAseq. These data provide valuable insight into the physiological, biochemical, and anatomical response of switchgrass when challenged by cereal aphids. Furthermore, continued screening of susceptible and resistant switchgrass germplasm will help researchers better understand the defensive systems operating in segregating switchgrass populations. Advisors: Tiffany Heng-Moss and Gautam Sarat

    Transcriptional responses of tolerant and susceptible soybeans to soybean aphid (\u3ci\u3eAphis glycines\u3c/i\u3e Matsumura) herbivory

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    The soybean aphid, Aphis glycines Matsumura, was introduced in 2000 to North America and has become one of the most significant pests to soybean, Glycine max (L.) Merrill, production. Possible solutions to this problem are the use of resistant plants and the understanding of the genes involved in plant resistance. In this study, we sought to better understand the genes involved in the tolerance response of soybean plants to the soybean aphid, utilizing tolerant (KS4202) and susceptible (K-03-4686) plants. Studies were conducted under greenhouse conditions. Leaf samples of both tolerant and susceptible plants were collected at day 5 and day 15 after infestation and analyzed by sequencing-by-synthesis on an Illumina GA II X instrument. In the tolerant genotype, 3 and 36 genes were found to be differentially expressed in the infested plants compared to the control treatments at day 5 and day 15, respectively. A similar comparison in the susceptible genotype revealed 0 and 11 genes to be differentially expressed at day 5 and day 15, respectively. Predominately, genes related to plant defense, such as WRKY transcription factors, peroxidases, and cytochrome p450s, were upregulated in the tolerant genotype 15 days post-infestation by aphids. In contrast, none of these genes were similarly up-regulated in the susceptible plants, suggesting that consistent elevation of defense responses is important to plant tolerance. However, significant genotypic differences in global gene expression were also found when transcriptomes from control uninfested plants were compared at both day 5 and 15. qPCR validation of select genes confirmed our RNA-seq data. These comparisons indicate that potentially broader regulation of transcriptomes also contributes to the tolerance response and provides data that the tolerant genotype (KS4202) could be useful in soybean breeding programs trying to minimize production losses accruing from soybean aphid feeding

    Biology and Economics of Recommendations for Insecticide-Based Management of Soybean Aphid

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    Soybean aphid, Aphis glycines Matsumura, remains the key insect pest of soybean, Glycine max (L.) Merrill, in the north-central United States. Management of this pest has relied primarily on scouting and application of foliar insecticides based on an economic threshold (ET) of 250 aphids per plant. This review explains why this ET remains valid for soybean aphid management, despite changes in crop value and input costs. In particular, we review how soybean aphid impacts soybean yield, the role of biology and economics in recommendations for soybean aphid management, and the short- and long-term consequences of inappropriately timed insecticide applications
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