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Sample records for hop glandular trichomes

  1. Terpene Biosynthesis in Glandular Trichomes of Hop12[W][OA

    PubMed Central

    Wang, Guodong; Tian, Li; Aziz, Naveed; Broun, Pierre; Dai, Xinbin; He, Ji; King, Andrew; Zhao, Patrick X.; Dixon, Richard A.

    2008-01-01

    Hop (Humulus lupulus L. Cannabaceae) is an economically important crop for the brewing industry, where it is used to impart flavor and aroma to beer, and has also drawn attention in recent years due to its potential pharmaceutical applications. Essential oils (mono- and sesquiterpenes), bitter acids (prenylated polyketides), and prenylflavonoids are the primary phytochemical components that account for these traits, and all accumulate at high concentrations in glandular trichomes of hop cones. To understand the molecular basis for terpene accumulation in hop trichomes, a trichome cDNA library was constructed and 9,816 cleansed expressed sequence tag (EST) sequences were obtained from random sequencing of 16,152 cDNA clones. The ESTs were assembled into 3,619 unigenes (1,101 contigs and 2,518 singletons). Putative functions were assigned to the unigenes based on their homology to annotated sequences in the GenBank database. Two mono- and two sesquiterpene synthases identified from the EST collection were expressed in Escherichia coli. Hop MONOTERPENE SYNTHASE2 formed the linear monterpene myrcene from geranyl pyrophosphate, whereas hop SESQUITERPENE SYNTHASE1 (HlSTS1) formed both caryophyllene and humulene from farnesyl pyrophosphate. Together, these enzymes account for the production of the major terpene constituents of the hop trichomes. HlSTS2 formed the minor sesquiterpene constituent germacrene A, which was converted to β-elemene on chromatography at elevated temperature. We discuss potential functions for other genes expressed at high levels in developing hop trichomes. PMID:18775972

  2. Characterization of the formation of branched short-chain fatty acid:CoAs for bitter acid biosynthesis in hop glandular trichomes.

    PubMed

    Xu, Haiyang; Zhang, Fengxia; Liu, Baoxiu; Huhman, David V; Sumner, Lloyd W; Dixon, Richard A; Wang, Guodong

    2013-07-01

    Bitter acids, known for their use as beer flavoring and for their diverse biological activities, are predominantly formed in hop (Humulus lupulus) glandular trichomes. Branched short-chain acyl-CoAs (e.g. isobutyryl-CoA, isovaleryl-CoA and 2-methylbutyryl-CoA), derived from the degradation of branched-chain amino acids (BCAAs), are essential building blocks for the biosynthesis of bitter acids in hops. However, little is known regarding what components are needed to produce and maintain the pool of branched short-chain acyl-CoAs in hop trichomes. Here, we present several lines of evidence that both CoA ligases and thioesterases are likely involved in bitter acid biosynthesis. Recombinant HlCCL2 (carboxyl CoA ligase) protein had high specific activity for isovaleric acid as a substrate (K cat /K m = 4100 s(-1) M(-1)), whereas recombinant HlCCL4 specifically utilized isobutyric acid (Kcat/K m = 1800 s(-1) M(-1)) and 2-methylbutyric acid (Kcat/K m = 6900 s(-1) M(-1)) as substrates. Both HlCCLs, like hop valerophenone synthase (HlVPS), were expressed strongly in glandular trichomes and localized to the cytoplasm. Co-expression of HlCCL2 and HlCCL4 with HlVPS in yeast led to significant production of acylphloroglucinols (the direct precursors for bitter acid biosynthesis), which further confirmed the biochemical function of these two HlCCLs in vivo. Functional identification of a thioesterase that catalyzed the reverse reaction of CCLs in mitochondria, together with the comprehensive analysis of genes involved BCAA catabolism, supported the idea that cytosolic CoA ligases are required for linking BCAA degradation and bitter acid biosynthesis in glandular trichomes. The evolution and other possible physiological roles of branched short-chain fatty acid:CoA ligases in planta are also discussed. PMID:23300257

  3. A Rapid Method for Isolating Glandular Trichomes

    PubMed Central

    Yerger, Ellen H.; Grazzini, Richard A.; Hesk, David; Cox-Foster, Diana L.; Craig, Richard; Mumma, Ralph O.

    1992-01-01

    A physical method is described for the rapid isolation of plant trichomes, with emphasis on stalked glandular types. The technique involved breaking frozen trichomes with powdered dry ice and collection of glandular heads by sieving from larger tissue fragments. This method was applied to several plants that bear similar stalked trichomes: geranium (Pelargonium), potato (Solanum tuberosum), tomato (Lycopersicon esculentum), squash (Cucurbita pepo), and velvetleaf (Abutilon theophrasti). The tissue preparation was of sufficient quality without further purification for biochemical and molecular studies. The preparation maintained the biochemical integrity of the trichomes for active enzymes and usable nucleic acids. A large quantity of tissue can be harvested; for example, 351 milligrams dry weight of glandular trichomes were harvested from geranium pedicels in 12 hours. The utility of the technique was demonstrated by examining the fatty acid composition of tall glandular trichomes of geraniums, Pelargonium ×hortorum L.H. Bailey. These purified cells contained high concentrations of unusual ω5-unsaturated fatty acids, proportionally 23.4% of total fatty acids in the trichomes. When the trichomes were removed, the supporting tissue contained no ω5-fatty acids, thereby unequivocally localizing ω5-fatty acids to the trichomes. Because ω5-fatty acids are unique precursors for the biosynthesis of ω5-anacardic acids, we conclude that anacardic acid synthesis must occur in the glandular trichomes. ImagesFigure 1Figure 2 PMID:16668834

  4. Secreting Glandular Trichomes: More than Just Hairs

    PubMed Central

    Wagner, George J.

    1991-01-01

    Secreting glandular plant trichome types which accumulate large quantities of metabolic products in the space between their gland cell walls and cuticle permit the plant to amass secretions in a compartment that is virtually outside the plant body. These structures not only accumulate and store what are often phytotoxic oils but they position these compounds as an apparent first line of defense at the surface of the plant. Recent advances in methods for isolation and study of trichome glands have allowed more precise analysis of gland cell metabolism and enzymology. Isolation of mutants with altered trichome phenotypes provides new systems for probing the genetic basis of trichome development. These advances and their continuation can pave the way for future attempts at modification of trichome secretion. The biochemical capability of glandular secreting trichomes and the potential for its future manipulation to exploit this external storage compartment is the focus of this review. PMID:16668241

  5. Glandular Trichomes and Essential Oil of Thymus quinquecostatus

    PubMed Central

    Jia, Ping; Liu, Hanzhu; Gao, Ting; Xin, Hua

    2013-01-01

    The distribution and types of glandular trichomes and essential oil chemistry of Thymus quinquecostatus were studied. The glandular trichomes are distributed on the surface of stem, leaf, rachis, calyx and corolla, except petiole, pistil and stamen. Three morphologically distinct types of glandular trichomes are described. Peltate trichomes, consisting of a basal cell, a stalk cell and a 12-celled head, are distributed on the stem, leaf, corolla and outer side of calyx. Capitate trichomes, consisting of a unicellular base, a 1–2-celled stalk and a unicellular head, are distributed more diffusely than peltate ones, existing on stem, leaf, rachis and calyx. Digitiform trichomes are just distributed on the outer side of corolla, consisting of 1 basal cell, 3 stalk cells and 1 head cell. All three types of glandular trichomes can secrete essential oil, and in small capitate trichomes of rachis, all peltate trichomes and digitiform trichomes, essential oil is stored in a large subcuticular space, released by cuticle rupture, whereas, in other capitate trichomes, essential oil crosses the thin cuticle. The essential oil of T. quinquecostatus is yellow, and its content is highest in the growth period. 68 constituents were identified in the essential oils. The main constituent is linalool. PMID:24250266

  6. Induction of glandular and non-glandular trichomes by damage in leaves of Madia sativa under contrasting water regimes

    NASA Astrophysics Data System (ADS)

    Gonzáles, Wilfredo L.; Negritto, María A.; Suárez, Lorena H.; Gianoli, Ernesto

    2008-01-01

    Plant traits may play multiple functional roles simultaneously. Leaf trichomes have been related to resistance against herbivores as well as to enhanced water economy in the plant. In a greenhouse study, we evaluated the interactive effect of damage (control vs. mechanical damage) and water availability (control vs. low watering) on the expression of glandular and non-glandular leaf trichomes in the annual Chilean tarweed Madia sativa (Asteraceae). We found that the overall trichome density increased both after damage and when plants were grown under water shortage. Interestingly, the type of trichome induced after damage varied with each water environment. While damage induced glandular trichomes only under control watering, non-glandular trichomes were induced by damage only under experimental drought. Results indicate that in M. sativa glandular trichomes are equally induced by drought or damage but there is no additive effect of these factors. In both cases glandular trichome density apparently reached a limit, which may be interpreted in terms of constraint or efficacy. On the other hand, the synergistic effect of damage and drought on non-glandular trichomes might suggest that, compared to glandular ones, these trichomes are less responsive to each stress factor separately. Thus, for plants to induce non-glandular trichomes they must be subjected to a degree of stress above a threshold that was not reached for each individual factor in our experimental setting. We did not detect a significant correlation between trichome types. Thus, the contrasting patterns observed likely reflect independent responses of trichomes to the evaluated factors.

  7. The nonvolatile metabolome of sunflower linear glandular trichomes.

    PubMed

    Spring, Otmar; Pfannstiel, Jens; Klaiber, Iris; Conrad, Jürgen; Beifuß, Uwe; Apel, Lysanne; Aschenbrenner, Anna-Katharina; Zipper, Reinhard

    2015-11-01

    Uniseriate linear glandular trichomes occur on stems, leaves and flowering parts of Helianthus species and related taxa. Their metabolic activity and biological function are still poorly understood. A phytochemical study documented the accumulation of bisabolene type sesquiterpenes and flavonoids as the major constituents of the non-volatile metabolome of linear glandular trichomes in the common sunflower, Helianthus annuus. Besides known sesquiterpenes of the glandulone, helibisabonol and heliannuol type, four previously undescribed sesquiterpenes named glandulone D, E, F and helibisabonol C were identified by spectroscopic analysis. In addition, four known nevadensin type flavonoids varying in O-methoxy substitutions were found. None of them has previously been reported from Helianthus annuus. PMID:26412774

  8. Comparative Functional Genomic Analysis of Solanum Glandular Trichome Types1[W][OA

    PubMed Central

    McDowell, Eric T.; Kapteyn, Jeremy; Schmidt, Adam; Li, Chao; Kang, Jin-Ho; Descour, Anne; Shi, Feng; Larson, Matthew; Schilmiller, Anthony; An, Lingling; Jones, A. Daniel; Pichersky, Eran; Soderlund, Carol A.; Gang, David R.

    2011-01-01

    Glandular trichomes play important roles in protecting plants from biotic attack by producing defensive compounds. We investigated the metabolic profiles and transcriptomes to characterize the differences between different glandular trichome types in several domesticated and wild Solanum species: Solanum lycopersicum (glandular trichome types 1, 6, and 7), Solanum habrochaites (types 1, 4, and 6), Solanum pennellii (types 4 and 6), Solanum arcanum (type 6), and Solanum pimpinellifolium (type 6). Substantial chemical differences in and between Solanum species and glandular trichome types are likely determined by the regulation of metabolism at several levels. Comparison of S. habrochaites type 1 and 4 glandular trichomes revealed few differences in chemical content or transcript abundance, leading to the conclusion that these two glandular trichome types are the same and differ perhaps only in stalk length. The observation that all of the other species examined here contain either type 1 or 4 trichomes (not both) supports the conclusion that these two trichome types are the same. Most differences in metabolites between type 1 and 4 glands on the one hand and type 6 glands on the other hand are quantitative but not qualitative. Several glandular trichome types express genes associated with photosynthesis and carbon fixation, indicating that some carbon destined for specialized metabolism is likely fixed within the trichome secretory cells. Finally, Solanum type 7 glandular trichomes do not appear to be involved in the biosynthesis and storage of specialized metabolites and thus likely serve another unknown function, perhaps as the site of the synthesis of protease inhibitors. PMID:21098679

  9. Tobacco NtLTP1, a glandular-specific lipid transfer protein, is required for lipid secretion from glandular trichomes.

    PubMed

    Choi, Yong Eui; Lim, Soon; Kim, Hyun-Jung; Han, Jung Yeon; Lee, Mi-Hyun; Yang, Yanyan; Kim, Ji-Ah; Kim, Yun-Soo

    2012-05-01

    Glandular trichomes are the phytochemical factories of plants, and they secrete a wide range of commercially important natural products such as lipids, terpenes and flavonoids. Herein, we report that the Nicotiana tabacum LTP1 (NtLTP1) gene, which is specifically expressed in long glandular trichomes, plays a role in lipid secretion from trichome heads. NtLTP1 mRNA is abundantly transcribed in trichomes, but NtLTP3, NtLTP4 and NtLTP5 are not. In situ hybridization revealed that NtLTP1 mRNAs accumulate specifically in long trichomes and not in short trichomes or epidermal cells. X-gluc staining of leaves from a transgenic plant expressing the NtLTP1 promoter fused to a GUS gene revealed that NtLTP1 protein accumulated preferentially on the tops of long glandular trichomes. GFP fluorescence from transgenic tobacco plants expressing an NtLTP1-GFP fusion protein was localized at the periphery of cells and in the excreted liquid droplets from the glandular trichome heads. In vitro assays using a fluorescent 2-p-toluidinonaphthalene-6-sulfonate probe indicated that recombinant NtLTP1 had lipid-binding activity. The overexpression of NtLTP1 in transgenic tobacco plants resulted in the increased secretion of trichome exudates, including epicuticular wax. In transgenic NtLTP1-RNAi lines, liquid secretion from trichomes was strongly reduced, but epicuticular wax secretion was not altered. Moreover, transgenic tobacco plants overexpressing NtLTP1 showed increased protection against aphids. Taken together, these data suggest that NtLTP1 is abundantly expressed in long glandular trichomes, and may play a role in lipid secretion from long glandular trichomes. PMID:22171964

  10. Variation in the number of capitate glandular trichomes in wild and cultivated sunflower germplasm and potential for use in host plant resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Capitate glandular trichomes of wild sunflower (Helianthus spp.) are considered an effective defense against the sunflower moth, Homoeosoma electellum (Hulst), but cultivated sunflowers are reportedly deficient in glandular trichomes. To investigate whether glandular trichomes have a role in protect...

  11. Genetic basis for glandular trichome formation in cotton.

    PubMed

    Ma, Dan; Hu, Yan; Yang, Changqing; Liu, Bingliang; Fang, Lei; Wan, Qun; Liang, Wenhua; Mei, Gaofu; Wang, Lingjian; Wang, Haiping; Ding, Linyun; Dong, Chenguang; Pan, Mengqiao; Chen, Jiedan; Wang, Sen; Chen, Shuqi; Cai, Caiping; Zhu, Xiefei; Guan, Xueying; Zhou, Baoliang; Zhu, Shuijin; Wang, Jiawei; Guo, Wangzhen; Chen, Xiaoya; Zhang, Tianzhen

    2016-01-01

    Trichomes originate from epidermal cells and can be classified as either glandular or non-glandular. Gossypium species are characterized by the presence of small and darkly pigmented lysigenous glands that contain large amounts of gossypol. Here, using a dominant glandless mutant, we characterize GoPGF, which encodes a basic helix-loop-helix domain-containing transcription factor, that we propose is a positive regulator of gland formation. Silencing GoPGF leads to a completely glandless phenotype. A single nucleotide insertion in GoPGF, introducing a premature stop codon is found in the duplicate recessive glandless mutant (gl2gl3). The characterization of GoPGF helps to unravel the regulatory network of glandular structure biogenesis, and has implications for understanding the production of secondary metabolites in glands. It also provides a potential molecular basis to generate glandless seed and glanded cotton to not only supply fibre and oil but also provide a source of protein for human consumption. PMID:26795254

  12. Genetic basis for glandular trichome formation in cotton

    PubMed Central

    Ma, Dan; Hu, Yan; Yang, Changqing; Liu, Bingliang; Fang, Lei; Wan, Qun; Liang, Wenhua; Mei, Gaofu; Wang, Lingjian; Wang, Haiping; Ding, Linyun; Dong, Chenguang; Pan, Mengqiao; Chen, Jiedan; Wang, Sen; Chen, Shuqi; Cai, Caiping; Zhu, Xiefei; Guan, Xueying; Zhou, Baoliang; Zhu, Shuijin; Wang, Jiawei; Guo, Wangzhen; Chen, Xiaoya; Zhang, Tianzhen

    2016-01-01

    Trichomes originate from epidermal cells and can be classified as either glandular or non-glandular. Gossypium species are characterized by the presence of small and darkly pigmented lysigenous glands that contain large amounts of gossypol. Here, using a dominant glandless mutant, we characterize GoPGF, which encodes a basic helix-loop-helix domain-containing transcription factor, that we propose is a positive regulator of gland formation. Silencing GoPGF leads to a completely glandless phenotype. A single nucleotide insertion in GoPGF, introducing a premature stop codon is found in the duplicate recessive glandless mutant (gl2gl3). The characterization of GoPGF helps to unravel the regulatory network of glandular structure biogenesis, and has implications for understanding the production of secondary metabolites in glands. It also provides a potential molecular basis to generate glandless seed and glanded cotton to not only supply fibre and oil but also provide a source of protein for human consumption. PMID:26795254

  13. Engineering of Tomato Glandular Trichomes for the Production of Specialized Metabolites.

    PubMed

    Kortbeek, R W J; Xu, J; Ramirez, A; Spyropoulou, E; Diergaarde, P; Otten-Bruggeman, I; de Both, M; Nagel, R; Schmidt, A; Schuurink, R C; Bleeker, P M

    2016-01-01

    Glandular trichomes are specialized tissues on the epidermis of many plant species. On tomato they synthesize, store, and emit a variety of metabolites such as terpenoids, which play a role in the interaction with insects. Glandular trichomes are excellent tissues for studying the biosynthesis of specialized plant metabolites and are especially suitable targets for metabolic engineering. Here we describe the strategy for engineering tomato glandular trichomes, first with a transient expression system to provide proof of trichome specificity of selected promoters. Using microparticle bombardment, the trichome specificity of a terpene-synthase promoter could be validated in a relatively fast way. Second, we describe a method for stable expression of genes of interest in trichomes. Trichome-specific expression of another terpene-synthase promoter driving the yellow-fluorescence protein-gene is presented. Finally, we describe a case of the overexpression of farnesyl diphosphate synthase (FPS), specifically in tomato glandular trichomes, providing an important precursor in the biosynthetic pathway of sesquiterpenoids. FPS was targeted to the plastid aiming to engineer sesquiterpenoid production, but interestingly leading to a loss of monoterpenoid production in the transgenic tomato trichomes. With this example we show that trichomes are amenable to engineering though, even with knowledge of a biochemical pathway, the result of such engineering can be unexpected. PMID:27480691

  14. Bidirectional secretions from glandular trichomes of pyrethrum enable immunization of seedlings.

    PubMed

    Ramirez, Aldana M; Stoopen, Geert; Menzel, Tila R; Gols, Rieta; Bouwmeester, Harro J; Dicke, Marcel; Jongsma, Maarten A

    2012-10-01

    Glandular trichomes are currently known only to store mono- and sesquiterpene compounds in the subcuticular cavity just above the apical cells of trichomes or emit them into the headspace. We demonstrate that basipetal secretions can also occur, by addressing the organization of the biosynthesis and storage of pyrethrins in pyrethrum (Tanacetum cinerariifolium) flowers. Pyrethrum produces a diverse array of pyrethrins and sesquiterpene lactones for plant defense. The highest concentrations accumulate in the flower achenes, which are densely covered by glandular trichomes. The trichomes of mature achenes contain sesquiterpene lactones and other secondary metabolites, but no pyrethrins. However, during achene maturation, the key pyrethrin biosynthetic pathway enzyme chrysanthemyl diphosphate synthase is expressed only in glandular trichomes. We show evidence that chrysanthemic acid is translocated from trichomes to pericarp, where it is esterified into pyrethrins that accumulate in intercellular spaces. During seed maturation, pyrethrins are then absorbed by the embryo, and during seed germination, the embryo-stored pyrethrins are recruited by seedling tissues, which, for lack of trichomes, cannot produce pyrethrins themselves. The findings demonstrate that plant glandular trichomes can selectively secrete in a basipetal direction monoterpenoids, which can reach distant tissues, participate in chemical conversions, and immunize seedlings against insects and fungi. PMID:23104830

  15. Bidirectional Secretions from Glandular Trichomes of Pyrethrum Enable Immunization of Seedlings[W

    PubMed Central

    Ramirez, Aldana M.; Stoopen, Geert; Menzel, Tila R.; Gols, Rieta; Bouwmeester, Harro J.; Dicke, Marcel; Jongsma, Maarten A.

    2012-01-01

    Glandular trichomes are currently known only to store mono- and sesquiterpene compounds in the subcuticular cavity just above the apical cells of trichomes or emit them into the headspace. We demonstrate that basipetal secretions can also occur, by addressing the organization of the biosynthesis and storage of pyrethrins in pyrethrum (Tanacetum cinerariifolium) flowers. Pyrethrum produces a diverse array of pyrethrins and sesquiterpene lactones for plant defense. The highest concentrations accumulate in the flower achenes, which are densely covered by glandular trichomes. The trichomes of mature achenes contain sesquiterpene lactones and other secondary metabolites, but no pyrethrins. However, during achene maturation, the key pyrethrin biosynthetic pathway enzyme chrysanthemyl diphosphate synthase is expressed only in glandular trichomes. We show evidence that chrysanthemic acid is translocated from trichomes to pericarp, where it is esterified into pyrethrins that accumulate in intercellular spaces. During seed maturation, pyrethrins are then absorbed by the embryo, and during seed germination, the embryo-stored pyrethrins are recruited by seedling tissues, which, for lack of trichomes, cannot produce pyrethrins themselves. The findings demonstrate that plant glandular trichomes can selectively secrete in a basipetal direction monoterpenoids, which can reach distant tissues, participate in chemical conversions, and immunize seedlings against insects and fungi. PMID:23104830

  16. Glandular trichomes as an inflorescence defence mechanism against insect herbivores in Iberian columbines.

    PubMed

    Jaime, Rafael; Rey, Pedro J; Alcántara, Julio M; Bastida, Jesús M

    2013-08-01

    Glandular trichomes play a defensive role against herbivores in the leaves of many plant species. However, their functional role in inflorescences has not been studied, even though theory suggests that tissues with a higher fitness value, such as inflorescences, should be better defended. Using manipulative experiments, we analysed the defensive role of glandular trichomes against herbivorous insects in the inflorescence of Iberian columbines (genus Aquilegia), and its inter-population and inter-taxa variation in relation to herbivore abundance and potential selective pressure. The experiments were conducted in eight populations belonging to four subspecies of two columbines (Aquilegia vulgaris and Aquilegia pyrenaica). For each population, we estimated the density of glandular trichomes in the inflorescences, the abundance of insects stuck in the inflorescences, the abundance of small herbivorous insects, the incidence of damage on flowers and fruits, and the fruit set. The density of glandular trichomes on the inflorescence of A. vulgaris and A. pyrenaica was higher in regions of higher herbivore abundance. We also found that when the plants lose the protection of glandular trichomes, small insects have better access to flowers and fruits, causing more damage and reducing plant fitness. This study concludes that glandular trichomes are part of an adaptive response against phytophagous insect herbivory. The observed variation in herbivore pressure between taxa, likely caused by habitat differentiation, might have played a role in trait differentiation through divergent selection. This result adds evidence to the differentiation of the Iberian columbines through habitat specialization. PMID:23247688

  17. Influence of Environment on Glandular Trichomes and Composition of Essential Oil of Perovskia abrotanoides Karel.

    PubMed Central

    Oreizi, Elaheh; Rahiminejad, Mohammad Reza; Asghari, Gholamreza

    2014-01-01

    Background: Perovskia abrotanoides Karel. is a medicinal plant used in Iranian folk medicine as a pain killer. Forty-one components have been identified in P. abrotanoides samples collected from Baluchistan Province, and 29 components have been recognized in samples collected from Khorasan Province. The leaves of P. abrotanoides have glandular trichomes (capitates and peltate) on both sides of the lamina. Objectives: This study aimed to evaluate the variation of oil constituents of the plant and illustrate the glandular trichomes types and then show the influence of environment on oil constituents and glandular trichomes. Materials and Methods: The essential oil of the plant was obtained using hydrodistillation and the analysis of oils carried out using GC-MS. The anatomical analysis of leaves was done by fixing, coloring, and photoing the sections. Results: Glandular trichomes composed of capitates and peltate trichomes. The essential oil composition differs. Viridiflora and neryl acetate were not identified in yellow glandular trichomes. Conclusions: It seems that there is no relation between anatomical characteristics of the plant leaves and its essential oil composition. PMID:25625046

  18. Plant Glandular Trichomes as Targets for Breeding or Engineering of Resistance to Herbivores

    PubMed Central

    Glas, Joris J.; Schimmel, Bernardus C. J.; Alba, Juan M.; Escobar-Bravo, Rocío; Schuurink, Robert C.; Kant, Merijn R.

    2012-01-01

    Glandular trichomes are specialized hairs found on the surface of about 30% of all vascular plants and are responsible for a significant portion of a plant’s secondary chemistry. Glandular trichomes are an important source of essential oils, i.e., natural fragrances or products that can be used by the pharmaceutical industry, although many of these substances have evolved to provide the plant with protection against herbivores and pathogens. The storage compartment of glandular trichomes usually is located on the tip of the hair and is part of the glandular cell, or cells, which are metabolically active. Trichomes and their exudates can be harvested relatively easily, and this has permitted a detailed study of their metabolites, as well as the genes and proteins responsible for them. This knowledge now assists classical breeding programs, as well as targeted genetic engineering, aimed to optimize trichome density and physiology to facilitate customization of essential oil production or to tune biocide activity to enhance crop protection. We will provide an overview of the metabolic diversity found within plant glandular trichomes, with the emphasis on those of the Solanaceae, and of the tools available to manipulate their activities for enhancing the plant’s resistance to pests. PMID:23235331

  19. Peltate glandular trichomes of Colquhounia seguinii harbor new defensive clerodane diterpenoids.

    PubMed

    Li, Chun-Huan; Liu, Yan; Hua, Juan; Luo, Shi-Hong; Li, Sheng-Hong

    2014-09-01

    Glandular trichomes produce a wide variety of secondary metabolites that are considered as major defensive chemicals against herbivore attack. The morphology and secondary metabolites of the peltate glandular trichomes of a lianoid Labiatae, Colquhounia seguinii Vaniot, were investigated. Three new clerodane diterpenoids, seguiniilactones A-C (1-3), were identified through precise trichome collection with laser microdissection, metabolic analysis with ultra performance liquid chromatography-tandem mass spectrometer, target compound isolation with classical phytochemical techniques, structure elucidation with spectroscopic methods. All compounds showed significant antifeedant activity against a generalist plant-feeding insect Spodoptera exigua. Seguiniilactone A (1) was approximately 17-fold more potent than the commercial neem oil. α-Substituted α,β-unsaturated γ-lactone functionality was found to be crucial for strong antifeedant activity of this class of compounds. Quantitative results indicated that the levels of these compounds in the peltate glandular trichomes and leaves were sufficiently high to deter the feeding by generalist insects. Moderate antifungal activity was observed for seguiniilactone C (3) against six predominant fungal species isolated from the diseased leaves of C. seguinii, while seguiniilactones A and B were generally inactive. These findings suggested that seguiniilactones A-C might be specialized secondary metabolites in peltate glandular trichomes for the plant defense against insect herbivores and pathogens. PMID:25048077

  20. Changes in Structure and Histochemistry of Glandular Trichomes of Thymus quinquecostatus Celak

    PubMed Central

    Jia, Ping; Gao, Ting; Xin, Hua

    2012-01-01

    The types, morphology, distribution, structure, and development process of the glandular trichomes on the leaves of Thymus quinquecostatus Celak had been investigated in this study. Two different types of glandular trichomes were determined in detail, namely, capitate trichomes and peltate ones. Besides, there were distinct differences on morphology, distribution, structure, and development process between the two kinds of trichomes. As the peltate trichome stepping into senium stage, it caved in the epidermis integrally, which was different from the capitate one. The secretion of the capitate trichome contained essential oil, polyphenols, and flavonoids, while, in addition to these three components, the secretion of the peltate one also contained acid polysaccharides. A distinctive difference was also seen in the secretory pathway of the secretion between the two types of trichomes. The secretion of capitate one was extruded through the cuticle of the head cell, but the secretion of the peltate one kept accumulating in the subcuticular space of the head cells until it was released by cuticle rupture. PMID:22545009

  1. Biochemical and histochemical localization of monoterpene biosynthesis in the glandular trichomes of spearmint (Mentha spicata)

    SciTech Connect

    Gershenzon, J.; Maffei, M.; Croteau, R. )

    1989-04-01

    The primary monoterpene accumulated in the glandular trichomes of spearmint (Mentha spicata) is the ketone (-)-carvone which is formed by cyclization of the C{sub 10} isoprenoid intermediate geranyl pyrophosphate to the olefin (-)-limonene, hydroxylation to (-)-trans-carveol and subsequent dehydrogenation. Selective extraction of the contents of the glandular trichomes indicated that essentially all of the cyclase and hydroxylase activities resided in these structures, whereas only about 30% of the carveol dehydrogenase was located here with the remainder located in the rest of the leaf. This distribution of carveol dehydrogenase activity was confirmed by histochemical methods. Electrophoretic analysis of the partially purified carveol dehydrogenase from extracts of both the glands and the leaves following gland removal indicated the presence of a unique carveol dehydrogenase species in the glandular trichomes, suggesting that the other dehydrogenase found throughout the leaf probably utilizes carveol only as an adventitious substrate. These results demonstrate that carvone biosynthesis takes place exclusively in the glandular trichomes in which this natural product accumulates.

  2. Biochemical and Histochemical Localization of Monoterpene Biosynthesis in the Glandular Trichomes of Spearmint (Mentha spicata) 12

    PubMed Central

    Gershenzon, Jonathan; Maffei, Massimo; Croteau, Rodney

    1989-01-01

    The primary monoterpene accumulated in the glandular trichomes of spearmint (Mentha spicata) is the ketone (−)-carvone which is formed by cyclization of the C10 isoprenoid intermediate geranyl pyrophosphate to the olefin (−)-limonene, hydroxylation to (−)-trans-carveol and subsequent dehydrogenation. Selective extraction of the contents of the glandular trichomes indicated that essentially all of the cyclase and hydroxylase activities resided in these structures, whereas only about 30% of the carveol dehydrogenase was located here with the remainder located in the rest of the leaf. This distribution of carveol dehydrogenase activity was confirmed by histochemical methods. Electrophoretic analysis of the partially purified carveol dehydrogenase from extracts of both the glands and the leaves following gland removal indicated the presence of a unique carveol dehydrogenase species in the glandular trichomes, suggesting that the other dehydrogenase found throughout the leaf probably utilizes carveol only as an adventitious substrate. These results demonstrate that carvone biosynthesis takes place exclusively in the glandular trichomes in which this natural product accumulates. Images Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 PMID:16666709

  3. Phytotoxicity of Constituents of Glandular Trichomes and the Leaf Surface of Camphorweed, Heterotheca subaxillaris

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Camphorweed, Heterotheca subaxillaris (Lam.) Britt. & Rusby has a camphor-like odor, and its leaf surfaces contain glandular trichomes of the type shown to contain high levels of isoprenoids in other species. Phytotoxic calamenene-type sesquiterpenes (1-4, 8-10), borneol (11) and methylated flavone...

  4. Capitate glandular trichomes in Aldama discolor (Heliantheae - Asteraceae): morphology, metabolite profile and sesquiterpene biosynthesis.

    PubMed

    Bombo, A B; Appezzato-da-Glória, B; Aschenbrenner, A-K; Spring, O

    2016-05-01

    The capitate glandular trichome is the most common type described in Asteraceae species. It is known for its ability to produce various plant metabolites of ecological and economic importance, among which sesquiterpene lactones are predominant. In this paper, we applied microscopy, phytochemical and molecular genetics techniques to characterise the capitate glandular trichome in Aldama discolor, a native Brazilian species of Asteraceae, with pharmacological potential. It was found that formation of trichomes on leaf primordia of germinating seeds starts between 24 h and 48 h after radicle growth indicates germination. The start of metabolic activity of trichomes was indicated by separation of the cuticle from the cell wall of secretory cells at the trichome tip after 72 h. This coincided with the accumulation of budlein A, the major sesquiterpene lactone of A. discolor capitate glandular trichomes, in extracts of leaf primordia after 96 h. In the same timeframe of 72-96 h post-germination, gene expression studies showed up-regulation of the putative germacrene A synthase (pGAS2) and putative germacrene A oxidase (pGAO) of A. discolor in the transcriptome of these samples, indicating the start of sesquiterpene lactone biosynthesis. Sequencing of the two genes revealed high similarity to HaGAS and HaGAO from sunflower, which shows that key steps of this pathway are highly conserved. The processes of trichome differentiation, metabolic activity and genetic regulation in A. discolor and in sunflower appear to be typical for other species of the subtribe Helianthinae. PMID:26642998

  5. Leaf Peltate Glandular Trichomes of Vernonia galamensis ssp. galamensis var. ethiopica Gilbert: Development, Ultrastructure and Chemical Composition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plants from the genus Vernonia produce a variety of flavonoids and bitter sesquiterpene lactones important for agriculture and human health. Leaf glandular trichomes of Vernonia galamensis ssp. galamensis var. ethiopica Gilbert (VGAE) were investigated for ultrastructural development and content com...

  6. Transcriptional profiling unravels potential metabolic activities of the olive leaf non-glandular trichome.

    PubMed

    Koudounas, Konstantinos; Manioudaki, Maria E; Kourti, Anna; Banilas, Georgios; Hatzopoulos, Polydefkis

    2015-01-01

    The olive leaf trichomes are multicellular peltate hairs densely distributed mainly at the lower leaf epidermis. Although, non-glandular, they have gained much attention since they significantly contribute to abiotic and biotic stress tolerance of olive leaves. The exact mechanisms by which olive trichomes achieve these goals are not fully understood. They could act as mechanical barrier but they also accumulate high amounts of flavonoids among other secondary metabolites. However, little is currently known about the exact compounds they produce and the respective metabolic pathways. Here we present the first EST analysis from olive leaf trichomes by using 454-pyrosequencing. A total of 5368 unigenes were identified out of 7258 high quality reads with an average length of 262 bp. Blast search revealed that 27.5% of them had high homologies to known proteins. By using Blast2GO, 1079 unigenes (20.1%) were assigned at least one Gene Ontology (GO) term. Most of the genes were involved in cellular and metabolic processes and in binding functions followed by catalytic activity. A total of 521 transcripts were mapped to 67 KEGG pathways. Olive trichomes represent a tissue of highly unique transcriptome as per the genes involved in developmental processes and the secondary metabolism. The results indicate that mature olive trichomes are trancriptionally active, mainly through the potential production of enzymes that contribute to phenolic compounds with important roles in biotic and abiotic stress responses. PMID:26322070

  7. Transcriptional profiling unravels potential metabolic activities of the olive leaf non-glandular trichome

    PubMed Central

    Koudounas, Konstantinos; Manioudaki, Maria E.; Kourti, Anna; Banilas, Georgios; Hatzopoulos, Polydefkis

    2015-01-01

    The olive leaf trichomes are multicellular peltate hairs densely distributed mainly at the lower leaf epidermis. Although, non-glandular, they have gained much attention since they significantly contribute to abiotic and biotic stress tolerance of olive leaves. The exact mechanisms by which olive trichomes achieve these goals are not fully understood. They could act as mechanical barrier but they also accumulate high amounts of flavonoids among other secondary metabolites. However, little is currently known about the exact compounds they produce and the respective metabolic pathways. Here we present the first EST analysis from olive leaf trichomes by using 454-pyrosequencing. A total of 5368 unigenes were identified out of 7258 high quality reads with an average length of 262 bp. Blast search revealed that 27.5% of them had high homologies to known proteins. By using Blast2GO, 1079 unigenes (20.1%) were assigned at least one Gene Ontology (GO) term. Most of the genes were involved in cellular and metabolic processes and in binding functions followed by catalytic activity. A total of 521 transcripts were mapped to 67 KEGG pathways. Olive trichomes represent a tissue of highly unique transcriptome as per the genes involved in developmental processes and the secondary metabolism. The results indicate that mature olive trichomes are trancriptionally active, mainly through the potential production of enzymes that contribute to phenolic compounds with important roles in biotic and abiotic stress responses. PMID:26322070

  8. Autofluorescence as a Signal to Sort Developing Glandular Trichomes by Flow Cytometry.

    PubMed

    Bergau, Nick; Navarette Santos, Alexander; Henning, Anja; Balcke, Gerd U; Tissier, Alain

    2016-01-01

    The industrial relevance of a number of metabolites produced in plant glandular trichomes (GTs) has spurred research on these specialized organs for a number of years. Most of the research, however, has focused on the elucidation of secondary metabolite pathways and comparatively little has been undertaken on the development and differentiation of GTs. One way to gain insight into these developmental processes is to generate stage-specific transcriptome and metabolome data. The difficulty for this resides in the isolation of early stages of development of the GTs. Here we describe a method for the separation and isolation of intact young and mature type VI trichomes from the wild tomato species Solanum habrochaites. The final and key step of the method uses cell sorting based on distinct autofluorescence signals of the young and mature trichomes. We demonstrate that sorting by flow cytometry allows recovering pure fractions of young and mature trichomes. Furthermore, we show that the sorted trichomes can be used for transcript and metabolite analyses. Because many plant tissues or cells have distinct autofluorescence components, the principles of this method can be generally applicable for the isolation of specific cell types without prior labeling. PMID:27446176

  9. Autofluorescence as a Signal to Sort Developing Glandular Trichomes by Flow Cytometry

    PubMed Central

    Bergau, Nick; Navarette Santos, Alexander; Henning, Anja; Balcke, Gerd U.; Tissier, Alain

    2016-01-01

    The industrial relevance of a number of metabolites produced in plant glandular trichomes (GTs) has spurred research on these specialized organs for a number of years. Most of the research, however, has focused on the elucidation of secondary metabolite pathways and comparatively little has been undertaken on the development and differentiation of GTs. One way to gain insight into these developmental processes is to generate stage-specific transcriptome and metabolome data. The difficulty for this resides in the isolation of early stages of development of the GTs. Here we describe a method for the separation and isolation of intact young and mature type VI trichomes from the wild tomato species Solanum habrochaites. The final and key step of the method uses cell sorting based on distinct autofluorescence signals of the young and mature trichomes. We demonstrate that sorting by flow cytometry allows recovering pure fractions of young and mature trichomes. Furthermore, we show that the sorted trichomes can be used for transcript and metabolite analyses. Because many plant tissues or cells have distinct autofluorescence components, the principles of this method can be generally applicable for the isolation of specific cell types without prior labeling. PMID:27446176

  10. The Key Role of Peltate Glandular Trichomes in Symbiota Comprising Clavicipitaceous Fungi of the Genus Periglandula and Their Host Plants

    PubMed Central

    Steiner, Ulrike; Hellwig, Sabine; Ahimsa-Müller, Mahalia A.; Grundmann, Nicola; Li, Shu-Ming; Drewke, Christel; Leistner, Eckhard

    2015-01-01

    Clavicipitaceous fungi producing ergot alkaloids were recently discovered to be epibiotically associated with peltate glandular trichomes of Ipomoea asarifolia and Turbina corymbosa, dicotyledonous plants of the family Convolvulaceae. Mediators of the close association between fungi and trichomes may be sesquiterpenes, main components in the volatile oil of different convolvulaceous plants. Molecular biological studies and microscopic investigations led to the observation that the trichomes do not only secrete sesquiterpenes and palmitic acid but also seem to absorb ergot alkaloids from the epibiotic fungal species of the genus Periglandula. Thus, the trichomes are likely to have a dual and key function in a metabolic dialogue between fungus and host plant. PMID:25894995

  11. The key role of peltate glandular trichomes in symbiota comprising clavicipitaceous fungi of the genus periglandula and their host plants.

    PubMed

    Steiner, Ulrike; Kucht, Sabine Hellwig neé; Ahimsa-Müller, Mahalia A; Grundmann, Nicola; Li, Shu-Ming; Drewke, Christel; Leistner, Eckhard

    2015-04-01

    Clavicipitaceous fungi producing ergot alkaloids were recently discovered to be epibiotically associated with peltate glandular trichomes of Ipomoea asarifolia and Turbina corymbosa, dicotyledonous plants of the family Convolvulaceae. Mediators of the close association between fungi and trichomes may be sesquiterpenes, main components in the volatile oil of different convolvulaceous plants. Molecular biological studies and microscopic investigations led to the observation that the trichomes do not only secrete sesquiterpenes and palmitic acid but also seem to absorb ergot alkaloids from the epibiotic fungal species of the genus Periglandula. Thus, the trichomes are likely to have a dual and key function in a metabolic dialogue between fungus and host plant. PMID:25894995

  12. Comparison of oxalate formation from ascorbic and glyoxyl acids in detached glandular heads of tobacco trichomes

    SciTech Connect

    Vogeli-Lange, R.; Wagner, G.J.

    1987-08-01

    Ca-oxalate crystal containing cells from detached glandular heads of trichomes from Nicotiana tabacum, TI 1068, are capable of converting (1-/sup 14/C) ascorbic acid (AA) and (1-/sup 14/C) glyoxylic acid (GA) to oxalate. AA was found to be a better precursor for oxalate formation than GA. In detached glandular heads, 3.6x more label was converted to oxalate from AA than from GA, in the epidermis the factor was 3x while that with petiole tissue was 7x. Oxalate formation from AA, in detached glandular heads, was only partially inhibited in the dark and in the presence of metabolic inhibitors, suggesting that a nonenzymatic component might be involved. Oxalate formation from GA increased in the presence of metabolic inhibitors. During treatment of detached glandular heads with 2 mM Ca-acetate for 2 days, oxalate formation from AA was stimulated 3 fold, while the presence of 2mM Ca-acetate had no effect on the oxalate formation from GA. These results suggest that Ca/sup 2 +/ stimulates the formation of Ca-oxalate crystals in glandular head cells, and that AA can serve as a precursor for oxalate production.

  13. Light, Conventional and Environmental Scanning Electron Microscopy of the Trichomes of Cucurbita pepo subsp. pepo var. styriaca and Histochemistry of Glandular Secretory Products

    PubMed Central

    KOLB, DAGMAR; MÜLLER, MARIA

    2004-01-01

    • Background and Aims In the present study, the differences between glandular and non-glandular trichomes, the secretory process and the method of secretion were studied. Previous studies on leaves of Styrian oil pumpkin (Cucurbia pepo var. styriaca) plants have shown that four morphologically and ontogenetically independent glandular and non-glandular trichome types and one bristle hair type can be distinguished. The four types of trichomes can be categorized into three glandular trichome types: type I, a short-stalked trichome with four head cells including a ‘middle-cell’, two stalk cells and one basal cell; type II, a long-stalked trichome with two head cells, a ‘neck-cell’ region and a long stalk area; type IV, a ‘stipitate-capitate’ trichome with a mesophyll cell basement, a short stalk and a multicellular head; type III, a non-glandular ‘columnar-digit’ trichome, which consists of two head cells continuous with three-celled stalk, and the basal cell. • Methods The histochemical studies (the main classes of metabolite in secreted material of glandular trichomes) were conducted in fresh and fixed hand sections, using the following tests: Sudan black B, Nile blue A, osmium tetroxide, neutral red, Naturstoffreagent A, FSA (fuchsin–safranin–astra blue), NADI (naphthol + dimethylparaphenylenediamine) and ruthenium red. Each suggested differences in the intercalations during the ontogenetical development of each trichome during the development stage. • Key Results The histochemical reactions revealed the main components of the materials secreted by all types of trichomes, which include lipids, flavones and terpenes and the different cell wall compositions. Glandular secretions were observed during environmental scanning electron microscopy (ESEM) and the trichomes compared with those seen by conventional scanning electron microscopy (CSEM). • Conclusions Scanning electron microscopy and histochemical analysis demonstrated that each of

  14. Molecular cloning and functional characterization of borneol dehydrogenase from the glandular trichomes of Lavandula x intermedia.

    PubMed

    Sarker, Lukman S; Galata, Mariana; Demissie, Zerihun A; Mahmoud, Soheil S

    2012-12-15

    Several varieties of Lavandula x intermedia (lavandins) are cultivated for their essential oils (EOs) for use in cosmetic, hygiene and personal care products. These EOs are mainly constituted of monoterpenes including camphor, which contributes an off odor reducing the olfactory appeal of the oil. We have recently constructed a cDNA library from the glandular trichomes (the sites of EO synthesis) of L. x intermedia plants. Here, we describe the cloning of a borneol dehydrogenase cDNA (LiBDH) from this library. The 780 bp open reading frame of the cDNA encoded a 259 amino acid short chain alcohol dehydrogenase with a predicted molecular mass of ca. 27.5 kDa. The recombinant LiBDH was expressed in Escherichia coli, purified by Ni-NTA agarose affinity chromatography, and functionally characterized in vitro. The bacterially produced enzyme specifically converted borneol to camphor as the only product with K(m) and k(cat) values of 53 μM and 4.0 × 10(-4) s(-1), respectively. The LiBDH transcripts were specifically expressed in glandular trichomes of mature flowers indicating that like other Lavandula monoterpene synthases the expression of this gene is regulated in a tissue-specific manner. The cloning of LiBDH has far reaching implications in improving the quality of Lavandula EOs through metabolic engineering. PMID:23058847

  15. Cloning of a sesquiterpene synthase from Lavandula x intermedia glandular trichomes.

    PubMed

    Sarker, Lukman S; Demissie, Zerihun A; Mahmoud, Soheil S

    2013-11-01

    The essential oil (EO) of Lavandula is dominated by monoterpenes, but can also contain small amounts of sesquiterpenes, depending on species and environmental conditions. For example, the sesquiterpene 9-epi-caryophyllene can make up to 8 % of the EO in a few species, including those commercially propagated for EO production. Here, we report the cloning and functional characterization of 9-epi-caryophyllene synthase (LiCPS) from the glandular trichomes of Lavandula x intermedia, cv. Grosso. The 1,617 bp open reading frame of LiCPS, which did not encode a transit peptide, was expressed in Escherichia coli and the recombinant protein purified by Ni-NTA agarose affinity chromatography. The ca. 60 kDa recombinant protein specifically converted farnesyl diphosphate to 9-epi-caryophyllene. LiCPS also produced a few monoterpenes when assayed with the monoterpene precursor geranyl diphosphate (GPP), but--unlike most monoterpene synthases--was not able to derive detectable amounts of any products from the cis isomer of GPP, neryl diphosphate. The LiCPS transcripts accumulated in developing L. x intermedia flowers and were highly enriched in glandular trichomes, but were not detected in leaves suggesting that the transcriptional expression of this gene is spatially and developmentally regulated. PMID:23918183

  16. Development and Structure of Internal Glands and External Glandular Trichomes in Pogostemon cablin

    PubMed Central

    Guo, Jiansheng; Yuan, Yongming; Liu, Zhixue; Zhu, Jian

    2013-01-01

    Pogostemon cablin possesses two morphologically and ontogenetically different types of glandular trichomes, one type of bristle hair on the surfaces of leaves and stems and one type of internal gland inside the leaves and stems. The internal gland originates from elementary meristem and is associated with the biosynthesis of oils present inside the leaves and stems. However, there is little information on mechanism for the oil biosynthesis and secretion inside the leaves and stems. In this study, we identified three kinds of glandular trichome types and two kinds of internal gland in the Pogostemon cablin. The oil secretions from internal glands of stems and leaves contained lipids, flavones and terpenes. Our results indicated that endoplasmic reticulum and plastids and vacuoles are likely involved in the biosynthesis of oils in the internal glands and the synthesized oils are transported from endoplasmic reticulum to the cell wall via connecting endoplasmic reticulum membranes to the plasma membrane. And the comparative analysis of the development, distribution, histochemistry and ultrastructures of the internal and external glands in Pogostemon cablin leads us to propose that the internal gland may be a novel secretory structure which is different from external glands. PMID:24205002

  17. Identifying Three Ecological Chemotypes of Xanthium strumarium Glandular Trichomes Using a Combined NMR and LC-MS Method

    PubMed Central

    Gou, Junbo; Lu, Dayan; Gong, Fujun; Tang, Huiru; Zhang, Yansheng

    2013-01-01

    Xanthanolides, as the sesquiterpene lactones, are reportedly the major components for the pharmacological properties of X. strumarium L. species. Phytochemical studies indicated that the glandular structures on the surface of plant tissues would form the primary sites for the accumulation of this class of the compounds. As the interface between plants and their natural enemies, glandular trichomes may vary with respect to which of their chemicals are sequestered against different herbivores in different ecologies. However, to date, no data are available on the chemical characterisation of X. strumarium glandular cells. In this study, the trichome secretions of the X. strumarium species originating from nineteen unique areas across eleven provinces in China, were analysed by HPLC, LC-ESI-MS and NMR. For the first time three distinct chemotypes of X. strumarium glandular trichomes were discovered along with the qualitative and quantitative evaluations of their presence of xanthanolides; these were designated glandular cell Types I, II, and III, respectively. The main xanthanolides in Type I cells were 8-epi-xanthatin and xanthumin while no xanthatin was detected. Xanthatin, 8-epi-xanthatin, and xanthumin dominated in Type II cells with comparable levels of each being present. For Type III cells, significantly higher concentrations of 8-epi-xanthatin or xanthinosin (relative to xanthatin) were detected with xanthinosin only being observed in this type. Further research will focus on understanding the ecological and molecular mechanism causing these chemotype differences in X. strumarium glandular structures. PMID:24098541

  18. Identifying three ecological chemotypes of Xanthium strumarium glandular trichomes using a combined NMR and LC-MS method.

    PubMed

    Chen, Fangfang; Hao, Fuhua; Li, Changfu; Gou, Junbo; Lu, Dayan; Gong, Fujun; Tang, Huiru; Zhang, Yansheng

    2013-01-01

    Xanthanolides, as the sesquiterpene lactones, are reportedly the major components for the pharmacological properties of X. strumarium L. species. Phytochemical studies indicated that the glandular structures on the surface of plant tissues would form the primary sites for the accumulation of this class of the compounds. As the interface between plants and their natural enemies, glandular trichomes may vary with respect to which of their chemicals are sequestered against different herbivores in different ecologies. However, to date, no data are available on the chemical characterisation of X. strumarium glandular cells. In this study, the trichome secretions of the X. strumarium species originating from nineteen unique areas across eleven provinces in China, were analysed by HPLC, LC-ESI-MS and NMR. For the first time three distinct chemotypes of X. strumarium glandular trichomes were discovered along with the qualitative and quantitative evaluations of their presence of xanthanolides; these were designated glandular cell Types I, II, and III, respectively. The main xanthanolides in Type I cells were 8-epi-xanthatin and xanthumin while no xanthatin was detected. Xanthatin, 8-epi-xanthatin, and xanthumin dominated in Type II cells with comparable levels of each being present. For Type III cells, significantly higher concentrations of 8-epi-xanthatin or xanthinosin (relative to xanthatin) were detected with xanthinosin only being observed in this type. Further research will focus on understanding the ecological and molecular mechanism causing these chemotype differences in X. strumarium glandular structures. PMID:24098541

  19. Opposing Roles of Foliar and Glandular Trichome Volatile Components in Cultivated Nightshade Interaction with a Specialist Herbivore.

    PubMed

    Murungi, Lucy Kananu; Kirwa, Hillary; Salifu, Daisy; Torto, Baldwyn

    2016-01-01

    Plant chemistry is an important contributor to the interaction with herbivores. Here, we report on a previously unknown role for foliar and glandular trichome volatiles in their interaction with the specialist herbivore of solanaceous plants, the tomato red spider mite Tetranychus evansi. We used various bioassays and chemical analyses including coupled gas chromatography-mass spectrometry (GC/MS) and liquid chromatography coupled to quadrupole time of flight mass spectrometry (LC-QToF-MS) to investigate this interaction between cultivated African nightshades and T. evansi. We show that, whereas morphologically different cultivated African nightshade species released similar foliar volatile organic compounds (VOCs) that attracted T. evansi, VOCs released from exudates of ruptured glandular trichomes of one nightshade species influenced local defense on the leaf surface. VOCs from ruptured glandular trichomes comprising mainly saturated and unsaturated fatty acids deterred T. evansi oviposition. Of the fatty acids, the unsaturated fatty acids accounted for >40% of the oviposition deterrent activity. Our findings point to a defense strategy in a plant, based on opposing roles for volatiles released by foliar and glandular trichomes in response to attack by a specialist herbivore. PMID:27556560

  20. Opposing Roles of Foliar and Glandular Trichome Volatile Components in Cultivated Nightshade Interaction with a Specialist Herbivore

    PubMed Central

    Murungi, Lucy Kananu; Kirwa, Hillary; Salifu, Daisy; Torto, Baldwyn

    2016-01-01

    Plant chemistry is an important contributor to the interaction with herbivores. Here, we report on a previously unknown role for foliar and glandular trichome volatiles in their interaction with the specialist herbivore of solanaceous plants, the tomato red spider mite Tetranychus evansi. We used various bioassays and chemical analyses including coupled gas chromatography-mass spectrometry (GC/MS) and liquid chromatography coupled to quadrupole time of flight mass spectrometry (LC-QToF-MS) to investigate this interaction between cultivated African nightshades and T. evansi. We show that, whereas morphologically different cultivated African nightshade species released similar foliar volatile organic compounds (VOCs) that attracted T. evansi, VOCs released from exudates of ruptured glandular trichomes of one nightshade species influenced local defense on the leaf surface. VOCs from ruptured glandular trichomes comprising mainly saturated and unsaturated fatty acids deterred T. evansi oviposition. Of the fatty acids, the unsaturated fatty acids accounted for >40% of the oviposition deterrent activity. Our findings point to a defense strategy in a plant, based on opposing roles for volatiles released by foliar and glandular trichomes in response to attack by a specialist herbivore. PMID:27556560

  1. Localization of sesquiterpene lactone biosynthesis in cells of capitate glandular trichomes of Helianthus annuus (Asteraceae).

    PubMed

    Amrehn, Evelyn; Aschenbrenner, Anna-Katharina; Heller, Annerose; Spring, Otmar

    2016-03-01

    Capitate glandular trichomes (CGT) of sunflower, Helianthus annuus, synthesize bioactive sesquiterpene lactones (STLs) within a short period of only a few days during trichome development. In the current project, the subcellular localization of H. annuus germacrene A monooxygenase (HaGAO), a key enzyme of the STL biosynthesis in sunflower CGT, was investigated. A polyclonal antibody raised against this enzyme was used for immunolabelling. HaGAO was found in secretory and stalk cells of CGT. This correlated with the appearance of smooth endoplasmic reticulum in both cell types. Stalk cells and secretory cells differed in form, size and types of plastids, but both had structures necessary for secretion. No HaGAO-specific immunoreaction was found in sunflower leaf tissue outside of CGT or in developing CGT before the secretory phase had started. Our results indicated that not only secretory cells but also nearly all cells of the CGT were involved in the biosynthesis of STL and that this process was not linked to the presence or absence of a specific type of plastid. PMID:25956500

  2. Negative ion 'chip-based' nanospray tandem mass spectrometry for the analysis of flavonoids in glandular trichomes of Lychnophora ericoides Mart. (Asteraceae).

    PubMed

    Gobbo-Neto, Leonardo; Gates, Paul J; Lopes, Norberto P

    2008-12-01

    This paper reports a method for the analysis of secondary metabolites stored in glandular trichomes, employing negative ion 'chip-based' nanospray tandem mass spectrometry. The analyses of glandular trichomes from Lychnophora ericoides, a plant endemic to the Brazilian 'cerrado' and used in traditional medicine as an anti-inflammatory and analgesic agent, led to the identification of five flavonoids (chrysin, pinocembrin, pinostrobin, pinobanksin and 3-O-acetylpinobanksin) by direct infusion of the extracts of glandular trichomes into the nanospray ionisation source. All the flavonoids have no oxidation at ring B, which resulted in a modification of the fragmentation pathways compared with that of the oxidised 3,4-dihydroflavonoids already described in the literature. The absence of the anti-inflammatory and antioxidant di-C-glucosylflavone vicenin-2, or any other flavonoid glycosides, in the glandular trichomes was also demonstrated. The use of the 'chip-based' nanospray QqTOF apparatus is a new fast and useful tool for the identification of secondary metabolites stored in the glandular trichomes, which can be useful for chemotaxonomic studies based on metabolites from glandular trichomes. PMID:18980260

  3. Promoters of AaGL2 and AaMIXTA-Like1 genes of Artemisia annua direct reporter gene expression in glandular and non-glandular trichomes

    PubMed Central

    Jindal, Sunita; Longchar, Bendangchuchang; Singh, Alka; Gupta, Vikrant

    2015-01-01

    Herein, we report cloning and analysis of promoters of GLABRA2 (AaGL2) homolog and a MIXTA-Like (AaMIXTA-Like1) gene from Artemisia annua. The upstream regulatory regions of AaGL2 and AaMIXTA-Like1 showed the presence of several crucial cis-acting elements. Arabidopsis and A. annua seedlings were transiently transfected with the promoter-GUS constructs using a robust agro-infiltration method. Both AaGL2 and AaMIXTA-Like1 promoters showed GUS expression preferentially in Arabidopsis single-celled trichomes and glandular as well as T-shaped trichomes of A. annua. Transgenic Arabidopsis harboring constructs in which AaGL2 or AaMIXTA-Like1 promoters would control GFP expression, showed fluorescence emanating specifically from trichome cells. Our study provides a fast and efficient method to study trichome-specific expression, and 2 promoters that have potential for targeted metabolic engineering in plants. PMID:26340695

  4. Glandular trichomes and essential oil composition of endemic Sideritis italica (Mill.) Greuter et Burdet from central Italy.

    PubMed

    Giuliani, Claudia; Bini, Laura Maleci; Papa, Fabrizio; Cristalli, Gloria; Sagratini, Gianni; Vittori, Sauro; Lucarini, Domenico; Maggi, Filippo

    2011-12-01

    Sideritis italica (Mill.) Greuter et Burdet belongs to the Lamiaceae family and is endemic to Italy. The glandular trichomes (morphology, distribution, histochemistry, and ultrastructure) of the plant were studied for the first time, along with the chemical composition of the essential oils. Abundant non-glandular hairs and peltate (type A) and capitate (types B, C(1), and C(x)) glandular trichomes were observed both on the vegetative and reproductive organs. The histochemical procedures and the ultrastructural investigation enabled specific location of the main site of essential oil production mainly in type-A peltate hairs. Particular emphasis is given to the release mechanism of the secreted material in all of the types of glands, and the potential taxonomic value of the indumentum in the Lamiaceae family is briefly discussed. Essential oils were hydrodistilled from flowering aerial parts of S. italica, and 136 compounds (112 in flowerheads, 79 in vegetative parts) were identified. The quantitative prevalence of diterpenoids (43.4% in flowerheads and 22.3% in vegetative parts) was the most significant characteristic of the essential oil of S. italica that could be classified as a diterpene-rich essential oil according to the classification of Kirimer. PMID:22162157

  5. Identification and characterization of two bisabolene synthases from linear glandular trichomes of sunflower (Helianthus annuus L., Asteraceae).

    PubMed

    Aschenbrenner, Anna-Katharina; Kwon, Moonhyuk; Conrad, Jürgen; Ro, Dae-Kyun; Spring, Otmar

    2016-04-01

    Sunflower is known to produce a variety of bisabolene-type sesquiterpenes and accumulates these substances in trichomes of leaves, stems and flowering parts. A bioinformatics approach was used to identify the enzyme responsible for the initial step in the biosynthesis of these compounds from its precursor farnesyl pyrophosphate. Based on sequence similarity with a known bisabolene synthases from Arabidopsis thaliana AtTPS12, candidate genes of Helianthus were searched in EST-database and used to design specific primers. PCR experiments identified two candidates in the RNA pool of linear glandular trichomes of sunflower. Their sequences contained the typical motifs of sesquiterpene synthases and their expression in yeast functionally characterized them as bisabolene synthases. Spectroscopic analysis identified the stereochemistry of the product of both enzymes as (Z)-γ-bisabolene. The origin of the two sunflower bisabolene synthase genes from the transcripts of linear trichomes indicates that they may be involved in the synthesis of sesquiterpenes produced in these trichomes. Comparison of the amino acid sequences of the sunflower bisabolene synthases showed high similarity with sesquiterpene synthases from other Asteracean species and indicated putative evolutionary origin from a β-farnesene synthase. PMID:26880289

  6. Glandular trichome density and essential oil composition in leaves and inflorescences of Lippia origanoides Kunth (Verbenaceae) in the Brazilian Cerrado.

    PubMed

    Tozin, Luiz R S; Marques, Marcia O M; Rodrigues, Tatiane M

    2015-01-01

    The essential oils from leaves and inflorescences of Lippia origanoides Kunth present aromatic and medicinal potential and have been used to treat several diseases, including melanoma. In Brazil, L. origanoides is commonly found in campo cerrado and cerrado stricto sensu, physiognomies featured mainly by the differential light conditions to which short and medium-sized plants are subjected. Our aim was to investigate the glandular trichome density and the yield and chemical composition of the essential oils in leaves and inflorescences of L. origanoides from campo cerrado and cerrado stricto sensu. For glandular density analysis, leaves and inflorescences were processed according to conventional techniques for scanning electron microscopy. The essential oils of leaves and inflorescences were obtained by hydrodistillation and identified with gas chromatography. Bracts and sepals showed the highest glandular density, followed by petals and leaves. The glandular density in the abaxial leaf surface was higher in individuals from the campo cerrado. In both populations the essential oil yield was higher in inflorescences than in leaves. The chemical composition of the essential oils varied among individuals from different areas and inside a same population. Our results demonstrated the chemical plasticity of L. origanoides suggesting the importance of monitoring its popular use. PMID:26131639

  7. Single-Cell Metabolite Profiling of Stalk and Glandular Cells of Intact Trichomes with Internal Electrode Capillary Pressure Probe Electrospray Ionization Mass Spectrometry.

    PubMed

    Nakashima, Taiken; Wada, Hiroshi; Morita, Satoshi; Erra-Balsells, Rosa; Hiraoka, Kenzo; Nonami, Hiroshi

    2016-03-15

    In this report, we developed the pressure probe electrospray ionization-mass spectrometry with internal electrode capillary (IEC-PPESI-MS) which enables high spatial-resolution cell sampling, precise postsampling manipulation, and high detection sensitivity. Using this technique, a comparative in situ single-cell metabolite profiling of stalk and glandular cells, the two adjacent cell types comprising a trichome unit in tomato plants (Solanum lycopersicum L.), were performed to clarify the extent of metabolic differentiation between two cell types as well as among different types of trichomes. Owing to high sensitivity of the system, less than a picoliter cell sap from a single stalk cell sufficiently yielded a number of peaks of amino acids, organic acids, carbohydrates, and flavonoids. The minimal cell sap removal from a stalk cell without severe disturbance of trichome structure enabled sequential analysis of adjacent glandular cell on the same trichome, which showed the presence of striking differences in metabolite compositions between two adjacent cell types. Comparison among different types of trichome also revealed significant variations in metabolite profiles, particularly in flavonoids and acyl sugars compositions. Some metabolites were found only in specific cell types or particular trichome types. Although extensive metabolomics analysis of glandular cells of tomato trichomes has been previously documented, this is the first report describing cell-to-cell variations in metabolite compositions of stalk and glandular cells as well as in different trichome types. Further application of this technique may provide new insights into distinct metabolism in plant cells displaying variations in shape, size, function and physicochemical properties. PMID:26845634

  8. Effects of Plant Density on the Number of Glandular Trichomes and on Yield and Quality of Essential Oils from Oregano.

    PubMed

    Tuttolomondo, Teresa; La Bella, Salvatore; Leto, Claudio; Bonsangue, Giuseppe; Leone, Raffaele; Gennaro, Maria Cristina; Virga, Giuseppe; Inguanta, Rosalinda; Licata, Mario

    2016-06-01

    Plants yields are influenced by agronomic techniques. Plant density is a complex issue and extremely important when maximizing both crop quality, and biomass and essential oil yields. Plants belonging to the Origanum vulgare subspecies hirtum (Link) Ietswaart were grown adopting four types of plant density and were characterized in biometric and chemical terms. The samples were analyzed using the ANOVA (Principal Component Analysis) statistical method regarding biometric aspects, EO yield and peltate hair density. Essential oil (EO) was extracted by hydrodistillation and analyzed using GC-FID and GC-MS. GC-FID and GC-MS analysis led to the identification of 45 compounds from the EO. Plant density affected production both in terms of biomass and EO. However, it was not found to have affected peltate glandular trichome density or EO quality. PMID:27534133

  9. Differential microRNA Analysis of Glandular Trichomes and Young Leaves in Xanthium strumarium L. Reveals Their Putative Roles in Regulating Terpenoid Biosynthesis.

    PubMed

    Fan, Rongyan; Li, Yuanjun; Li, Changfu; Zhang, Yansheng

    2015-01-01

    The medicinal plant Xanthium strumarium L. (X. strumarium) is covered with glandular trichomes, which are the sites for synthesizing pharmacologically active terpenoids such as xanthatin. MicroRNAs (miRNAs) are a class of 21-24 nucleotide (nt) non-coding RNAs, most of which are identified as regulators of plant growth development. Identification of miRNAs involved in the biosynthesis of plant secondary metabolites remains limited. In this study, high-throughput Illumina sequencing, combined with target gene prediction, was performed to discover novel and conserved miRNAs with potential roles in regulating terpenoid biosynthesis in X. strumarium glandular trichomes. Two small RNA libraries from leaves and glandular trichomes of X. strumarium were established. In total, 1,185 conserved miRNAs and 37 novel miRNAs were identified, with 494 conserved miRNAs and 18 novel miRNAs being differentially expressed between the two tissue sources. Based on the X. strumarium transcriptome data that we recently constructed, 3,307 annotated mRNA transcripts were identified as putative targets of the differentially expressed miRNAs. KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis suggested that some of the differentially expressed miRNAs, including miR6435, miR5021 and miR1134, might be involved in terpenoid biosynthesis in the X. strumarium glandular trichomes. This study provides the first comprehensive analysis of miRNAs in X. strumarium, which forms the basis for further understanding of miRNA-based regulation on terpenoid biosynthesis. PMID:26406988

  10. Differential microRNA Analysis of Glandular Trichomes and Young Leaves in Xanthium strumarium L. Reveals Their Putative Roles in Regulating Terpenoid Biosynthesis

    PubMed Central

    Fan, Rongyan; Li, Yuanjun; Li, Changfu; Zhang, Yansheng

    2015-01-01

    The medicinal plant Xanthium strumarium L. (X. strumarium) is covered with glandular trichomes, which are the sites for synthesizing pharmacologically active terpenoids such as xanthatin. MicroRNAs (miRNAs) are a class of 21–24 nucleotide (nt) non-coding RNAs, most of which are identified as regulators of plant growth development. Identification of miRNAs involved in the biosynthesis of plant secondary metabolites remains limited. In this study, high-throughput Illumina sequencing, combined with target gene prediction, was performed to discover novel and conserved miRNAs with potential roles in regulating terpenoid biosynthesis in X. strumarium glandular trichomes. Two small RNA libraries from leaves and glandular trichomes of X. strumarium were established. In total, 1,185 conserved miRNAs and 37 novel miRNAs were identified, with 494 conserved miRNAs and 18 novel miRNAs being differentially expressed between the two tissue sources. Based on the X. strumarium transcriptome data that we recently constructed, 3,307 annotated mRNA transcripts were identified as putative targets of the differentially expressed miRNAs. KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway analysis suggested that some of the differentially expressed miRNAs, including miR6435, miR5021 and miR1134, might be involved in terpenoid biosynthesis in the X. strumarium glandular trichomes. This study provides the first comprehensive analysis of miRNAs in X. strumarium, which forms the basis for further understanding of miRNA-based regulation on terpenoid biosynthesis. PMID:26406988

  11. Methylerythritol and mevalonate pathway contributions to biosynthesis of mono-, sesqui-, and diterpenes in glandular trichomes and leaves of Stevia rebaudiana Bertoni.

    PubMed

    Wölwer-Rieck, Ursula; May, Bianca; Lankes, Christa; Wüst, Matthias

    2014-03-19

    The biosynthesis of the diterpenoid steviol glycosides rebaudioside A and stevioside in nonrooted cuttings of Stevia rebaudiana was investigated by feeding experiments using the labeled key precursors [5,5-(2)H2]-mevalonic acid lactone (d2-MVL) and [5,5-(2)H2]-1-deoxy-d-xylulose (d2-DOX). Labeled glycosides were extracted from the leaves and stems and were directly analyzed by LC-(-ESI)-MS/MS and by GC-MS after hydrolysis and derivatization of the resulting isosteviol to the corresponding TMS-ester. Additionally, the incorporation of the proffered d2-MVL and d2-DOX into volatile monoterpenes, sesquiterpenes, and diterpenes in glandular trichomes on leaves and stems was investigated by headspace-solid phase microextraction-GC-MS (HS-SPME-GC-MS). Incorporation of the labeled precursors indicated that diterpenes in leaves and monoterpenes and diterpenes in glandular trichomes are predominately biosynthesized via the methylerythritol phosphate (MEP) pathway, whereas both the MEP and mevalonate (MVA) pathways contribute to the biosynthesis of sesquiterpenes at equal rates in glandular trichomes. These findings give evidence for a transport of MEP pathway derived farnesyl diphosphate precursors from plastids to the cytosol. Contrarily, the transport of MVA pathway derived geranyl diphosphate and geranylgeranyl diphosphate precursors from the cytosol to the plastid is limited. PMID:24579920

  12. Quantitative determination of enhydrin in leaf rinse extracts and in glandular trichomes of Smallanthus sonchifolius (Asteraceae) by reversed-phase high-performance liquid chromatography.

    PubMed

    Schorr, Karin; Da Costa, Fernando B

    2005-01-01

    A simple, reliable and rapid reversed-phase HPLC-PAD procedure for the characterisation and quantitative determination of the anti-diabetic sesquiterpene lactone enhydrin (1) from Smallanthus sonchifolius (yacón) has been evaluated and validated. The approach focused on the analysis of various leaf rinse extracts, as well as the glandular trichomes of intact leaves, in which 1 was the major compound detected. The best sample preparation of a rinse extract yielded 0.67 mg/mL of 1, whilst a rapid rinse of a small piece of one dried leaf gave 0.09 mg/mL of 1; the highest concentration obtained from a glandular extract was 0.07 mg/mL. The dried leaves of S. sonchifolius were found to contain a total of 0.97% of 1. PMID:15997848

  13. A Geranylfarnesyl Diphosphate Synthase Provides the Precursor for Sesterterpenoid (C25) Formation in the Glandular Trichomes of the Mint Species Leucosceptrum canum.

    PubMed

    Liu, Yan; Luo, Shi-Hong; Schmidt, Axel; Wang, Guo-Dong; Sun, Gui-Ling; Grant, Marcus; Kuang, Ce; Yang, Min-Jie; Jing, Shu-Xi; Li, Chun-Huan; Schneider, Bernd; Gershenzon, Jonathan; Li, Sheng-Hong

    2016-03-01

    Plant sesterterpenoids, an important class of terpenoids, are widely distributed in various plants, including food crops. However, little is known about their biosynthesis. Here, we cloned and functionally characterized a plant geranylfarnesyl diphosphate synthase (Lc-GFDPS), the enzyme producing the C25 prenyl diphosphate precursor to all sesterterpenoids, from the glandular trichomes of the woody plant Leucosceptrum canum. GFDPS catalyzed the formation of GFDP after expression in Escherichia coli. Overexpressing GFDPS in Arabidopsis thaliana also gave an extract catalyzing GFDP formation. GFDPS was strongly expressed in glandular trichomes, and its transcript profile was completely in accordance with the sesterterpenoid accumulation pattern. GFDPS is localized to the plastids, and inhibitor studies indicated its use of isoprenyl diphosphate substrates supplied by the 2-C-methyl-D-erythritol 4-phosphate pathway. Application of a jasmonate defense hormone induced GFDPS transcript and sesterterpenoid accumulation, while reducing feeding and growth of the generalist insect Spodoptera exigua, suggesting that these C25 terpenoids play a defensive role. Phylogenetic analysis suggested that GFDPS probably evolved from plant geranylgeranyl diphosphate synthase under the influence of positive selection. The isolation of GFDPS provides a model for investigating sesterterpenoid formation in other species and a tool for manipulating the formation of this group in plants and other organisms. PMID:26941091

  14. Characterization and mechanism of (4S)-limonene synthase, a monoterpene cyclase from the glandular trichomes of peppermint (Mentha x piperita).

    PubMed

    Rajaonarivony, J I; Gershenzon, J; Croteau, R

    1992-07-01

    (4S)-Limonene synthase, a monoterpene cyclase isolated from the secretory cells of the glandular trichomes of Mentha x piperita (peppermint), catalyzes the cyclization of geranyl pyrophosphate to (4S)-limonene, a key intermediate in the biosynthesis of p-menthane monoterpenes in Mentha species. The enzyme synthesizes principally (-)-(4S)-limonene (greater than 94% of the total products), plus several other monoterpene olefins. The general properties of (4S)-limonene synthase resemble those of other monoterpene cyclases. The enzyme shows a pH optimum near 6.7, an isoelectric point of 4.35, and requires a divalent metal ion for catalysis, either Mg2+ or Mn2+, with Mn2+ preferred. The Km value measured for geranyl pyrophosphate was 1.8 microM. The activity of (4S)-limonene synthase was inhibited by sodium phosphate, sodium pyrophosphate, and reagents directed against the amino acids cysteine, methionine, and histidine. In the presence of Mn2+, geranyl pyrophosphate protected against cysteine-directed inhibition, suggesting that at least one cysteine residue is located at or near the active site. Experiments with alternate substrates and substrate analogs confirmed many elements of the proposed reaction mechanism, including the binding of geranyl pyrophosphate in the form of a complex with the divalent metal ion, the preliminary isomerization of geranyl pyrophosphate to linalyl pyrophosphate (a bound intermediate capable of cyclization), and the participation of a series of carbocation:pyrophosphate anion pairs in the reaction sequence. PMID:1605644

  15. Analysis of Natural and Induced Variation in Tomato Glandular Trichome Flavonoids Identifies a Gene Not Present in the Reference Genome[W][OPEN

    PubMed Central

    Kim, Jeongwoon; Matsuba, Yuki; Ning, Jing; Schilmiller, Anthony L.; Hammar, Dagan; Jones, A. Daniel; Pichersky, Eran; Last, Robert L.

    2014-01-01

    Flavonoids are ubiquitous plant aromatic specialized metabolites found in a variety of cell types and organs. Methylated flavonoids are detected in secreting glandular trichomes of various Solanum species, including the cultivated tomato (Solanum lycopersicum). Inspection of the sequenced S. lycopersicum Heinz 1706 reference genome revealed a close homolog of Solanum habrochaites MOMT1 3′/5′ myricetin O-methyltransferase gene, but this gene (Solyc06g083450) is missing the first exon, raising the question of whether cultivated tomato has a distinct 3′ or 3′/5′ O-methyltransferase. A combination of mining genome and cDNA sequences from wild tomato species and S. lycopersicum cultivar M82 led to the identification of Sl-MOMT4 as a 3′ O-methyltransferase. In parallel, three independent ethyl methanesulfonate mutants in the S. lycopersicum cultivar M82 background were identified as having reduced amounts of di- and trimethylated myricetins and increased monomethylated myricetin. Consistent with the hypothesis that Sl-MOMT4 is a 3′ O-methyltransferase gene, all three myricetin methylation defective mutants were found to have defects in MOMT4 sequence, transcript accumulation, or 3′-O-methyltransferase enzyme activity. Surprisingly, no MOMT4 sequence is found in the Heinz 1706 reference genome sequence, and this cultivar accumulates 3-methyl myricetin and is deficient in 3′-methyl myricetins, demonstrating variation in this gene among cultivated tomato varieties. PMID:25128240

  16. Influence of life history differences of two tachinid parasitoids ofHelicoverpa zea (Boddie) (Lepidoptera: Noctuidae) on their interactions with glandular trichome/methyl ketone-based insect resistance in tomato.

    PubMed

    Farrar, R R; Kennedy, G G; Kashyap, R K

    1992-03-01

    The effects of glandular trichome/methyl ketone (2-tridecanone and 2-undecanone) -based insect resistance in the wild tomato,Lycopersicon hirsutum f.glabratum C.H. Mull, accession PI 134417, onArchytas marmoratus (Townsend) andEucelatoria bryani (Sabrosky) (Diptera: Tachinidae), both parasitoids ofHelicoverpa (=Heliothis)zea (Boddie) (Lepidoptera: Noctuidae), were investigated in the laboratory.A. marmoratus deposits larvae (planidia) on the foliage of its host's food plant; planidia attach to passing hosts, penetrate the cuticle, and develop in the host pupae.E. bryani larviposits directly into its host; its larvae develop in the host larva.A. marmoratus planidia are killed by glandular trichomes of PI 134417 and also by trichomes of hybrid lines with no methyl ketones. The methyl ketones are toxic to planidia, but at least part of the effect is due to other factors, possibly physical entanglement. Both species can be affected indirectly by methyl ketones in the diet of the host. 2-Undecanone reduces the percentage ofA. marmoratus larvae that reach pupation. This effect is evidently due to premature death and desiccation of the host pupa caused by 2-undecanone. 2-Tridecanone in host diets had no effect onA. marmoratus. InE. bryani, 2-tridecanone in the diet of the host reduced the number of parasitoids yielded by each parasitized host, although not the overall percentage of hosts parasitized. 2-Undecanone in the diet of the host had no effect onE. bryani. PMID:24254953

  17. Trichome structure and evolution in Neotropical lianas

    PubMed Central

    Nogueira, Anselmo; El Ottra, Juliana Hanna Leite; Guimarães, Elza; Machado, Silvia Rodrigues; Lohmann, Lúcia G.

    2013-01-01

    Background and Aims Trichomes are epidermal outgrowths generally associated with protection against herbivores and/or desiccation that are widely distributed from ferns to angiosperms. Patterns of topological variation and morphological evolution of trichomes are still scarce in the literature, preventing valid comparisons across taxa. This study integrates detailed morphoanatomical data and the evolutionary history of the tribe Bignonieae (Bignoniaceae) in order to gain a better understanding of current diversity and evolution of trichome types. Methods Two sampling schemes were used to characterize trichome types: (1) macromorphological characterization of all 105 species currently included in Bignonieae; and (2) micromorphological characterization of 16 selected species. Individual trichome morphotypes were coded as binary in each vegetative plant part, and trichome density and size were coded as multistate. Ancestral character state reconstructions were conducted using maximum likelihood (ML) assumptions. Key Results Two main functional trichome categories were found: non-glandular and glandular. In glandular trichomes, three morphotypes were recognized: peltate (Pg), stipitate (Sg) and patelliform/cupular (P/Cg) trichomes. Non-glandular trichomes were uniseriate, uni- or multicellular and simple or branched. Pg and P/Cg trichomes were multicellular and non-vascularized with three clearly distinct cell layers. Sg trichomes were multicellular, uniseriate and long-stalked. ML ancestral character state reconstructions suggested that the most recent common ancestor (MRCA) of Bignonieae probably had non-glandular, Pg and P/Cg trichomes, with each trichome type presenting alternative histories of appearance on the different plant parts. For example, the MRCA of Bignonieae probably had non-glandular trichomes on the stems, prophylls, petiole, petiolule and leaflet veins while P/Cg trichomes were restricted to leaflet blades. Sg trichomes were not present in the MRCA

  18. Morphology and biochemistry of non-glandular trichomes in Cistus salvifolius L. leaves growing in extreme habitats of the Mediterranean basin.

    PubMed

    Tattini, M; Matteini, P; Saracini, E; Traversi, M L; Giordano, C; Agati, G

    2007-05-01

    Here the functional roles of stellate and dendritic trichomes in Cistus salvifolius L leaves were studied by analysing i) both leaf surface and trichome morphology using scanning electron and light microscopy; and ii) the composition and localisation of polyphenols by coupling liquid chromatography with fluorescence spectroscopy and fluorescence microimaging. Red-coloured compounds were detected in the stalk cells and the channel in the trichome arm, and appeared to be released at the tip end of the trichome branch. We identified such metabolites as ellagitannins, namely punicalagin and two galloyl derivatives of punicalagin. These ellagitannins accounted for 4.3 % of leaf dry weight and their concentration in the leaf leachate averaged 289.4 mg L (-1). The trichome arms exhibited an appreciable orange-red autofluorescence (centred at 620 nm) when excited with UV light (at 365 nm) or emitted in the yellow waveband (peak centred at 566 nm) when stained with the Naturstoff reagent, and excited at 488 nm. The fluorescence signatures of the trichome arms were consistent with the presence of mono-hydroxy B-ring substituted flavonoids, which were identified as the mono- and di-coumaroyl derivative of a kaempferol 3-O-glycoside. Our data may provide some insights on the functional roles of stellate and dendritic trichomes in the response mechanisms of C. salvifolius to Mediterranean-type climate, based upon (i) the potential effect of released ellagitannins on the soil nitrogen dynamic and (ii) the ability of acylated kaempferol 3-O-glycosides to effectively absorb both the UV-B and UV-A wavelengths. PMID:17143807

  19. Morphology, Structure, and Ontogeny of Trichomes of the Grape Genus (Vitis, Vitaceae).

    PubMed

    Ma, Zhi-Yao; Wen, Jun; Ickert-Bond, Stefanie M; Chen, Long-Qing; Liu, Xiu-Qun

    2016-01-01

    Trichomes are widely distributed on surfaces of different organs in the grape genus Vitis and are of taxonomic utility. To explore the morphology, structure and ontogeny of Vitis trichomes, we investigated the diversity and distribution of trichomes in 34 species of Vitis. Two main types of trichomes in Vitis are documented: non-glandular and glandular. Within non-glandular trichomes, ribbon and simple trichomes are found on different vegetative plant organs. The morphology and ontogeny of these types of trichomes are further examined with light microscopy and scanning electron microscopy. The ultrastructure of the glandular trichomes is explored with transmission electron microscopy. The ribbon trichomes are twisted, greatly elongated and unicellular, and this trichome type may be a morphological synapomorphy of Vitis and its closest tropical relative Ampelocissus and Pterisanthes in Vitaceae. The simple trichomes are documented in most species sampled in the genus. The glandular trichomes are multicellular, non-vascularized and composed of both epidermis and subjacent layers. We show that prickles occurring along the stems and petioles of Vitis davidii are modified glandular trichomes. We observed that glandular trichomes of V. romanetii secrete mucilage and volatile substances which trap insectes on the glands. Transmission electron microscopy indicates that metabolic products accumulate in vacuoles, the cytoplasm and intercellular spaces. We infer that glandular trichomes and young prickles are involved in the secretion of these metabolic products and the intercellular spaces may be the places of temporary storage of these secretions. PMID:27252720

  20. Morphology, Structure, and Ontogeny of Trichomes of the Grape Genus (Vitis, Vitaceae)

    PubMed Central

    Ma, Zhi-Yao; Wen, Jun; Ickert-Bond, Stefanie M.; Chen, Long-Qing; Liu, Xiu-Qun

    2016-01-01

    Trichomes are widely distributed on surfaces of different organs in the grape genus Vitis and are of taxonomic utility. To explore the morphology, structure and ontogeny of Vitis trichomes, we investigated the diversity and distribution of trichomes in 34 species of Vitis. Two main types of trichomes in Vitis are documented: non-glandular and glandular. Within non-glandular trichomes, ribbon and simple trichomes are found on different vegetative plant organs. The morphology and ontogeny of these types of trichomes are further examined with light microscopy and scanning electron microscopy. The ultrastructure of the glandular trichomes is explored with transmission electron microscopy. The ribbon trichomes are twisted, greatly elongated and unicellular, and this trichome type may be a morphological synapomorphy of Vitis and its closest tropical relative Ampelocissus and Pterisanthes in Vitaceae. The simple trichomes are documented in most species sampled in the genus. The glandular trichomes are multicellular, non-vascularized and composed of both epidermis and subjacent layers. We show that prickles occurring along the stems and petioles of Vitis davidii are modified glandular trichomes. We observed that glandular trichomes of V. romanetii secrete mucilage and volatile substances which trap insectes on the glands. Transmission electron microscopy indicates that metabolic products accumulate in vacuoles, the cytoplasm and intercellular spaces. We infer that glandular trichomes and young prickles are involved in the secretion of these metabolic products and the intercellular spaces may be the places of temporary storage of these secretions. PMID:27252720

  1. New Approaches for Studying and Exploiting an Old Protuberance, the Plant Trichome

    PubMed Central

    WAGNER, G. J.; WANG, E.; SHEPHERD, R. W.

    2004-01-01

    • Background and aims Much recent study of plant trichomes has focused on various aspects of glandular secreting trichomes (GSTs) and differentiation of simple trichomes. This Botanical Briefing will highlight: ‐ research on various aspects of, and manipulation of glandular secreting trichomes; ‐ molecular aspects of the differentiation and development of simple trichomes of arabidopsis and cotton; ‐ how methods for manipulation of model systems used in the above work can be applied to expand our understanding of less studied surface structures of plants. • Scope The Briefing will cover: ‐ established and suggested roles of simple and glandular secreting trichomes; ‐ recent results regarding solute and ion movement in trichomes; ‐ methods for isolating trichomes; ‐ recent studies of trichome differentiation and development; ‐ attempts to modify metabolism in secreting trichomes; ‐ efforts to exploit trichomes for commercial and agronomic purposes. PMID:14678941

  2. Trichomes as sensors: detecting activity on the leaf surface.

    PubMed

    Tooker, John F; Peiffer, Michelle; Luthe, Dawn S; Felton, Gary W

    2010-01-01

    The dramatic movements of some carnivorous plants species are triggered by sensory structures derived from trichomes. While unusual plant species such as the Venus fly trap and sundews may be expected to have elaborate sensors to capture their insect prey, more modest plant species might not be expected to have similar sensory capabilities. Our recent work, however, has revealed that glandular trichomes on tomato (Solanum lycopersicum) appear to have a function similar to trigger hairs of carnivorous species, acting as "early warning" sensors. Using a combination of behavioral, molecular, and biochemical techniques, we determined that caterpillars, moths and mechanical disruption upregulate signaling molecules and defensive genes found in glandular trichomes. Importantly, we discovered that plants whose trichomes have been broken respond more vigorously when their defenses were induced. Taken together, our results suggest that glandular trichomes can act as sensors that detect activity on the leaf surface, and ready plants for herbivore attack. PMID:20592816

  3. Terpenoid biosynthesis in trichomes--current status and future opportunities.

    PubMed

    Lange, B Markus; Turner, Glenn W

    2013-01-01

    Glandular trichomes are anatomical structures specialized for the synthesis of secreted natural products. In this review we focus on the description of glands that accumulate terpenoid essential oils and oleoresins. We also provide an in-depth account of the current knowledge about the biosynthesis of terpenoids and secretion mechanisms in the highly specialized secretory cells of glandular trichomes, and highlight the implications for metabolic engineering efforts. PMID:22979959

  4. Trichome morphogenesis in Arabidopsis.

    PubMed Central

    Schwab, B; Folkers, U; Ilgenfritz, H; Hülskamp, M

    2000-01-01

    Trichomes (plant hairs) in Arabidopsis thaliana are large non-secreting epidermal cells with a characteristic three-dimensional architecture. Because trichomes are easily accessible to a combination of genetic, cell biological and molecular methods they have become an ideal model system to study various aspects of plant cell morphogenesis. In this review we will summarize recent progress in the understanding of trichome morphogenesis. PMID:11128981

  5. Studies of the site and mode of biosynthesis of tobacco trichome exudate components.

    PubMed

    Kandra, L; Wagner, G J

    1988-09-01

    Detached glandular trichome head preparations and epidermal strips with and without trichome heads were used to identify glandular trichome heads as the site of sucrose ester biosynthesis in tobacco. Carbon dioxide in solution as well as sucrose, glucose, and acetate were shown to serve as precursors to both sucrose esters and duvatrienediol diterpenes in detached trichome heads or epidermal strips, and gaseous CO2 was also efficiently utilized by epidermal strips. Thus, glandular heads can biosynthesize these principal exudate components from a molecule as simple as CO2. While formation of duvatriendiols from all precursors tested and conversion of sucrose and glucose to sucrose esters was light dependent, utilization of acetate to label the 6-O-acetyl group of the glucose moiety of sucrose esters occurred equally well in light and dark. The data suggest that CO2 and/or monosaccharides produced in trichome head cells and perhaps that supplied by other epidermal cells can act as carbon sources for sucrose ester and duvatrienediol biosynthesis which occurs in the glandular trichome head. PMID:3138948

  6. Analysis of cannabinoids in laser-microdissected trichomes of medicinal Cannabis sativa using LCMS and cryogenic NMR.

    PubMed

    Happyana, Nizar; Agnolet, Sara; Muntendam, Remco; Van Dam, Annie; Schneider, Bernd; Kayser, Oliver

    2013-03-01

    Trichomes, especially the capitate-stalked glandular hairs, are well known as the main sites of cannabinoid and essential oil production of Cannabis sativa. In this study the distribution and density of various types of Cannabis sativa L. trichomes, have been investigated by scanning electron microscopy (SEM). Furthermore, glandular trichomes were isolated over the flowering period (8 weeks) by laser microdissection (LMD) and the cannabinoid profile analyzed by LCMS. Cannabinoids were detected in extracts of 25-143 collected cells of capitate-sessile and capitate stalked trichomes and separately in the gland (head) and the stem of the latter. Δ(9)-Tetrahydrocannabinolic acid [THCA (1)], cannabidiolic acid [CBDA (2)], and cannabigerolic acid [CBGA (3)] were identified as most-abundant compounds in all analyzed samples while their decarboxylated derivatives, Δ(9)-tetrahydrocannabinol [THC (4)], cannabidiol [CBD (5)], and cannabigerol [CBG (6)], co-detected in all samples, were present at significantly lower levels. Cannabichromene [CBC (8)] along with cannabinol (CBN (9)) were identified as minor compounds only in the samples of intact capitate-stalked trichomes and their heads harvested from 8-week old plants. Cryogenic nuclear magnetic resonance spectroscopy (NMR) was used to confirm the occurrence of major cannabinoids, THCA (1) and CBDA (2), in capitate-stalked and capitate-sessile trichomes. Cryogenic NMR enabled the additional identification of cannabichromenic acid [CBCA (7)] in the dissected trichomes, which was not possible by LCMS as standard was not available. The hereby documented detection of metabolites in the stems of capitate-stalked trichomes indicates a complex biosynthesis and localization over the trichome cells forming the glandular secretion unit. PMID:23280038

  7. A heteromeric membrane-bound prenyltransferase complex from hop catalyzes three sequential aromatic prenylations in the bitter acid pathway.

    PubMed

    Li, Haoxun; Ban, Zhaonan; Qin, Hao; Ma, Liya; King, Andrew J; Wang, Guodong

    2015-03-01

    Bitter acids (α and β types) account for more than 30% of the fresh weight of hop (Humulus lupulus) glandular trichomes and are well known for their contribution to the bitter taste of beer. These multiprenylated chemicals also show diverse biological activities, some of which have potential benefits to human health. The bitter acid biosynthetic pathway has been investigated extensively, and the genes for the early steps of bitter acid synthesis have been cloned and functionally characterized. However, little is known about the enzyme(s) that catalyze three sequential prenylation steps in the β-bitter acid pathway. Here, we employed a yeast (Saccharomyces cerevisiae) system for the functional identification of aromatic prenyltransferase (PT) genes. Two PT genes (HlPT1L and HlPT2) obtained from a hop trichome-specific complementary DNA library were functionally characterized using this yeast system. Coexpression of codon-optimized PT1L and PT2 in yeast, together with upstream genes, led to the production of bitter acids, but no bitter acids were detected when either of the PT genes was expressed by itself. Stepwise mutation of the aspartate-rich motifs in PT1L and PT2 further revealed the prenylation sequence of these two enzymes in β-bitter acid biosynthesis: PT1L catalyzed only the first prenylation step, and PT2 catalyzed the two subsequent prenylation steps. A metabolon formed through interactions between PT1L and PT2 was demonstrated using a yeast two-hybrid system, reciprocal coimmunoprecipitation, and in vitro biochemical assays. These results provide direct evidence of the involvement of a functional metabolon of membrane-bound prenyltransferases in bitter acid biosynthesis in hop. PMID:25564559

  8. Trichome-derived O-acyl sugars are a first meal for caterpillars that tags them for predation

    PubMed Central

    Weinhold, Alexander; Baldwin, Ian Thomas

    2011-01-01

    Plant glandular trichomes exude secondary metabolites with defensive functions, but these epidermal protuberances are surprisingly the first meal of Lepidopteran herbivores on Nicotiana attenuata. O-acyl sugars, the most abundant metabolite of glandular trichomes, impart a distinct volatile profile to the body and frass of larvae that feed on them. The headspace composition of Manduca sexta larvae is dominated by the branched chain aliphatic acids hydrolyzed from ingested O-acyl sugars, which waxes and wanes rapidly with trichome ingestion. In native habitats a ground-hunting predator, the omnivorous ant Pogonomyrmex rugosus, but not the big-eyed bug Geocoris spp., use these volatile aliphatic acids to locate their prey. PMID:21518882

  9. Trichome-derived O-acyl sugars are a first meal for caterpillars that tags them for predation.

    PubMed

    Weinhold, Alexander; Baldwin, Ian Thomas

    2011-05-10

    Plant glandular trichomes exude secondary metabolites with defensive functions, but these epidermal protuberances are surprisingly the first meal of Lepidopteran herbivores on Nicotiana attenuata. O-acyl sugars, the most abundant metabolite of glandular trichomes, impart a distinct volatile profile to the body and frass of larvae that feed on them. The headspace composition of Manduca sexta larvae is dominated by the branched chain aliphatic acids hydrolyzed from ingested O-acyl sugars, which waxes and wanes rapidly with trichome ingestion. In native habitats a ground-hunting predator, the omnivorous ant Pogonomyrmex rugosus, but not the big-eyed bug Geocoris spp., use these volatile aliphatic acids to locate their prey. PMID:21518882

  10. A cold-tolerant evergreen interspecific hybrid of Ocimum kilimandscharicum and Ocimum basilicum: analyzing trichomes and molecular variations.

    PubMed

    Dhawan, Sunita Singh; Shukla, Preeti; Gupta, Pankhuri; Lal, R K

    2016-05-01

    Ocimum (Lamiaceae) is an important source of essential oils and aroma chemicals especially eugenol, methyl eugenol, linalool, methyl chavicol etc. An elite evergreen hybrid has been developed from Ocimum kilimandscharicum and Ocimum basilicum, which demonstrated adaptive behavior towards cold stress. A comparative molecular analysis has been done through RAPD, AFLP, and ISSR among O. basilicum and O. kilimandscharicum and their evergreen cold-tolerant hybrid. The RAPD and AFLP analyses demonstrated similar results, i.e., the hybrid of O. basilicum and O. kilimandscharicum shares the same cluster with O. kilimandscharicum, while O. basilicum behaves as an outgroup, whereas in ISSR analysis, the hybrid genotype grouped in the same cluster with O. basilicum. Ocimum genotypes were analyzed and compared for their trichome density. There were distinct differences on morphology, distribution, and structure between the two kinds of trichomes, i.e., glandular and non-glandular. Glandular trichomes contain essential oils, polyphenols, flavonoids, and acid polysaccharides. Hair-like trichomes, i.e., non-glandular trichomes, help in keeping the frost away from the living surface cells. O. basilicum showed less number of non-glandular trichomes on leaves compared to O. kilimandscharicum and the evergreen cold-tolerant hybrid. Trichomes were analyzed in O. kilimandscharicum, O. basilicum, and their hybrid. An increased proline content at the biochemical level represents a higher potential to survive in a stress condition like cold stress. In our analysis, the proline content is quite higher in tolerant variety O. kilimandscharicum, low in susceptible variety O. basilicum, and intermediate in the hybrid. Gene expression analysis was done in O. basilicum, O. kilimandscharicum and their hybrid for TTG1, GTL1, and STICHEL gene locus which regulates trichome development and its formation and transcription factors WRKY and MPS involved in the regulation of plant responses to freezing

  11. Transcriptome profiling reveals roles of meristem regulators and polarity genes during fruit trichome development in cucumber (Cucumis sativus L.)

    PubMed Central

    Chen, Chunhua; Liu, Meiling; Jiang, Li; Liu, Xiaofeng; Zhao, Jianyu; Yan, Shuangshuang; Yang, Sen; Ren, Huazhong; Liu, Renyi; Zhang, Xiaolan

    2014-01-01

    Trichomes are epidermal hair-like structures that function in plant defence against biotic and abiotic stresses. Extensive studies have been performed on foliar trichomes development in Arabidopsis and tomato, but the molecular mechanism of fruit trichome formation remains elusive. Cucumber fruit is covered with trichomes (spines) that directly affect the appearance and quality of cucumber products. Here, we characterized the fruit spine development in wild-type (WT) cucumber and a spontaneous mutant, tiny branched hair (tbh). Our data showed that the cucumber trichome was multicellular and non-glandular, with malformed organelles and no endoreduplication. Fruit spine development was generally homogenous and marked by a rapid base expansion stage. Trichomes in the tbh mutant were tiny and branched, with increased density and aberrant cell shape. Transcriptome profiling indicated that meristem-related genes were highly enriched in the upregulated genes in the tbh versus the WT, as well as in WT spines after versus before base expansion, and that polarity regulators were greatly induced during spine base expansion. Quantitative reverse transcription PCR and in situ hybridization confirmed the differential expression of CUP-SHAPED COTYLEDON3 (CUC3) and SHOOT MERISTEMLESS (STM) during spine development. Therefore, cucumber trichomes are morphologically different from those of Arabidopsis and tomato, and their development may be regulated by a distinct pathway involving meristem genes and polarity regulators. PMID:24962999

  12. Transcriptome profiling reveals roles of meristem regulators and polarity genes during fruit trichome development in cucumber (Cucumis sativus L.).

    PubMed

    Chen, Chunhua; Liu, Meiling; Jiang, Li; Liu, Xiaofeng; Zhao, Jianyu; Yan, Shuangshuang; Yang, Sen; Ren, Huazhong; Liu, Renyi; Zhang, Xiaolan

    2014-09-01

    Trichomes are epidermal hair-like structures that function in plant defence against biotic and abiotic stresses. Extensive studies have been performed on foliar trichomes development in Arabidopsis and tomato, but the molecular mechanism of fruit trichome formation remains elusive. Cucumber fruit is covered with trichomes (spines) that directly affect the appearance and quality of cucumber products. Here, we characterized the fruit spine development in wild-type (WT) cucumber and a spontaneous mutant, tiny branched hair (tbh). Our data showed that the cucumber trichome was multicellular and non-glandular, with malformed organelles and no endoreduplication. Fruit spine development was generally homogenous and marked by a rapid base expansion stage. Trichomes in the tbh mutant were tiny and branched, with increased density and aberrant cell shape. Transcriptome profiling indicated that meristem-related genes were highly enriched in the upregulated genes in the tbh versus the WT, as well as in WT spines after versus before base expansion, and that polarity regulators were greatly induced during spine base expansion. Quantitative reverse transcription PCR and in situ hybridization confirmed the differential expression of CUP-SHAPED COTYLEDON3 (CUC3) and SHOOT MERISTEMLESS (STM) during spine development. Therefore, cucumber trichomes are morphologically different from those of Arabidopsis and tomato, and their development may be regulated by a distinct pathway involving meristem genes and polarity regulators. PMID:24962999

  13. A Heteromeric Membrane-Bound Prenyltransferase Complex from Hop Catalyzes Three Sequential Aromatic Prenylations in the Bitter Acid Pathway1[OPEN

    PubMed Central

    Li, Haoxun; Ban, Zhaonan; Qin, Hao; Ma, Liya; King, Andrew J.

    2015-01-01

    Bitter acids (α and β types) account for more than 30% of the fresh weight of hop (Humulus lupulus) glandular trichomes and are well known for their contribution to the bitter taste of beer. These multiprenylated chemicals also show diverse biological activities, some of which have potential benefits to human health. The bitter acid biosynthetic pathway has been investigated extensively, and the genes for the early steps of bitter acid synthesis have been cloned and functionally characterized. However, little is known about the enzyme(s) that catalyze three sequential prenylation steps in the β-bitter acid pathway. Here, we employed a yeast (Saccharomyces cerevisiae) system for the functional identification of aromatic prenyltransferase (PT) genes. Two PT genes (HlPT1L and HlPT2) obtained from a hop trichome-specific complementary DNA library were functionally characterized using this yeast system. Coexpression of codon-optimized PT1L and PT2 in yeast, together with upstream genes, led to the production of bitter acids, but no bitter acids were detected when either of the PT genes was expressed by itself. Stepwise mutation of the aspartate-rich motifs in PT1L and PT2 further revealed the prenylation sequence of these two enzymes in β-bitter acid biosynthesis: PT1L catalyzed only the first prenylation step, and PT2 catalyzed the two subsequent prenylation steps. A metabolon formed through interactions between PT1L and PT2 was demonstrated using a yeast two-hybrid system, reciprocal coimmunoprecipitation, and in vitro biochemical assays. These results provide direct evidence of the involvement of a functional metabolon of membrane-bound prenyltransferases in bitter acid biosynthesis in hop. PMID:25564559

  14. Ecological distribution of leaf stomata and trichomes among tree species in a Malaysian lowland tropical rain forest.

    PubMed

    Ichie, Tomoaki; Inoue, Yuta; Takahashi, Narumi; Kamiya, Koichi; Kenzo, Tanaka

    2016-07-01

    The vertical structure of a tropical rain forest is complex and multilayered, with strong variation of micro-environment with height up to the canopy. We investigated the relation between morphological traits of leaf surfaces and tree ecological characteristics in a Malaysian tropical rain forest. The shapes and densities of stomata and trichomes on the abaxial leaf surfaces and their relation with leaf characteristics such as leaf area and leaf mass per area (LMA) were studied in 136 tree species in 35 families with different growth forms in the tropical moist forest. Leaf physiological properties were also measured in 50 canopy and emergent species. Most tree species had flat type (40.4 %) or mound type (39.7 %) stomata. In addition, 84 species (61.76 %) in 22 families had trichomes, including those with glandular (17.65 %) and non-glandular trichomes (44.11 %). Most leaf characteristics significantly varied among the growth form types: species in canopy and emergent layers and canopy gap conditions had higher stomatal density, stomatal pore index (SPI), trichome density and LMA than species in understory and subcanopy layers, though the relation of phylogenetically independent contrasts to each characteristic was not statistically significant, except for leaf stomatal density, SPI and LMA. Intrinsic water use efficiency in canopy and emergent tree species with higher trichome densities was greater than in species with lower trichome densities. These results suggest that tree species in tropical rain forests adapt to a spatial difference in their growth forms, which are considerably affected by phylogenetic context, by having different stomatal and trichome shapes and/or densities. PMID:26879931

  15. Trichomes and chemical composition of the volatile oil of Trichogonia cinerea (Gardner) R. M. King & H. Rob. (Eupatorieae, Asteraceae).

    PubMed

    Fernandes, Yanne S; Trindade, Luma M P; Rezende, Maria Helena; Paula, José R; Gonçalves, Letícia A

    2016-03-01

    Trichogonia cinerea is endemic to Brazil and occurs in areas of cerrado and campo rupestre. In this study, we characterized the glandular and non-glandular trichomes on the aerial parts of this species, determined the principal events in the development of the former, and identified the main constituents of the volatile oil produced in its aerial organs. Fully expanded leaves, internodes, florets, involucral bracts, and stem apices were used for the characterization of trichomes. Leaves, internodes, florets, and involucral bracts were examined by light microscopy and scanning electron microscopy, whereas stem apices were examined only by light microscopy. Branches in the reproductive phase were used for the extraction and determination of the composition of the volatile oil. The species has three types of glandular trichomes, biseriate vesicular, biseriate pedunculate, and multicellular uniseriate, which secrete volatile oils and phenolic compounds. The major components identified in the volatile oil were 3,5-muuroladiene (39.56%) and butylated hydroxytoluene (13.07%). PMID:26982621

  16. Hopping robot

    DOEpatents

    Spletzer, Barry L.; Fischer, Gary J.; Marron, Lisa C.; Martinez, Michael A.; Kuehl, Michael A.; Feddema, John T.

    2001-01-01

    The present invention provides a hopping robot that includes a misfire tolerant linear actuator suitable for long trips, low energy steering and control, reliable low energy righting, miniature low energy fuel control. The present invention provides a robot with hopping mobility, capable of traversing obstacles significant in size relative to the robot and capable of operation on unpredictable terrain over long range. The present invention further provides a hopping robot with misfire-tolerant combustion actuation, and with combustion actuation suitable for use in oxygen-poor environments.

  17. Hydathode trichomes actively secreting water from leaves play a key role in the physiology and evolution of root-parasitic rhinanthoid Orobanchaceae

    PubMed Central

    Světlíková, Petra; Hájek, Tomáš; Těšitel, Jakub

    2015-01-01

    Background and Aims Root hemiparasites from the rhinanthoid clade of Orobanchaceae possess metabolically active glandular trichomes that have been suggested to function as hydathode trichomes actively secreting water, a process that may facilitate resource acquisition from the host plant’s root xylem. However, no direct evidence relating the trichomes to water secretion exists, and carbon budgets associated with this energy-demanding process have not been determined. Methods Macro- and microscopic observations of the leaves of hemiparasitic Rhinanthus alectorolophus were conducted and night-time gas exchange was measured. Correlations were examined among the intensity of guttation, respiration and transpiration, and analysis of these correlations allowed the carbon budget of the trichome activity to be quantified. We examined the intensity of guttation, respiration and transpiration, correlations among which indicate active water secretion. Key Results Guttation was observed on the leaves of 50 % of the young, non-flowering plants that were examined, and microscopic observations revealed water secretion from the glandular trichomes present on the abaxial leaf side. Night-time rates of respiration and transpiration and the presence of guttation drops were positively correlated, which is a clear indicator of hydathode trichome activity. Subsequent physiological measurements on older, flowering plants indicated neither intense guttation nor the presence of correlations, which suggests that the peak activity of hydathodes is in the juvenile stage. Conclusions This study provides the first unequivocal evidence for the physiological role of the hydathode trichomes in active water secretion in the rhinanthoid Orobanchaceae. Depending on the concentration of organic elements calculated to be in the host xylem sap, the direct effect of water secretion on carbon balance ranges from close to neutral to positive. However, it is likely to be positive in the xylem-only feeding

  18. EST analysis and annotation of transcripts derived from a trichome-specific cDNA library from Salvia fruticosa.

    PubMed

    Chatzopoulou, Fani M; Makris, Antonios M; Argiriou, Anagnostis; Degenhardt, Jörg; Kanellis, Angelos K

    2010-05-01

    Greek sage (Salvia fruticosa Mill., Syn. Salvia triloba L.) is appreciated for its essential oil which is used as an aromatic spice and active against a wide range of microorganisms and viruses. The essential oil is dominated by terpenoids and flavonoids which are produced and stored in glandular trichomes on the plant surface. The present study aims to give insights into the metabolic activities of S. fruticosa trichomes on a transcriptome level. A total of 2,304 clones were sequenced from a cDNA library from leaves' trichomes of S. fruticosa. Exclusion of sequences shorter than 100 bp resulted in 1,615 high-quality ESTs with a mean length of 592 bp. Cluster analysis indicated the presence of 197 contigs (908 clones) and 707 singletons, generating a total of 904 unique sequences. Of the 904 unique ESTs, 628 (69.5%) had significant hits in the non-redundant protein database and were annotated. A total of 517 (82.3%) sequences were functionally classified using the gene ontologies (GO) and established pathway associations to 220 (24.3%) sequences in Kyoto encyclopedia of genes and genomes (KEGG). In addition, 52 (5.8%) of the unique ESTs revealed a GO biological term with relation to terpenoid (78 ESTs), phenylpropanoid (43 ESTs), flavonoid (18 ESTs) or alkaloid (10 ESTs) biosynthesis or to P450s (26 ESTs). Expression analysis of a selected set of genes known to be involved in the pathways of secondary metabolite synthesis showed higher expression levels in trichomes, validating the tissue specificity of the analyzed glandular trichome library. PMID:20333525

  19. Proteomics of terpenoid biosynthesis and secretion in trichomes of higher plant species.

    PubMed

    Champagne, Antoine; Boutry, Marc

    2016-08-01

    Among the specialized (secondary) plant metabolites, terpenoids represent the most diverse family and are often involved in the defense against pathogens and herbivores. Terpenoids can be produced both constitutively and in response to the environment. At the front line of this defense strategy are the glandular trichomes, which are organs dedicated primarily to the production of specialized metabolites. Mass spectrometry-based proteomics is a powerful tool, which is very useful to investigate enzymes involved in metabolic pathways, such as the synthesis and secretion of terpenoids in glandular trichomes. Here we review the strategies used to investigate the specific roles of these particular organs from non-model plant species, mainly belonging to the Lamiaceae, Solanaceae, and Cannabaceae families. We discuss how proteomics helps to accurately pinpoint candidate proteins to be functionally characterized, and how technological progresses create opportunities for studying low-abundance proteins, such as the ones related to the synthesis and transport of specialized metabolites. This article is part of a Special Issue entitled: Plant Proteomics--a bridge between fundamental processes and crop production, edited by Dr. Hans-Peter Mock. PMID:26873244

  20. Quantification of variability in trichome patterns

    PubMed Central

    Greese, Bettina; Hülskamp, Martin; Fleck, Christian

    2014-01-01

    While pattern formation is studied in various areas of biology, little is known about the noise leading to variations between individual realizations of the pattern. One prominent example for de novo pattern formation in plants is the patterning of trichomes on Arabidopsis leaves, which involves genetic regulation and cell-to-cell communication. These processes are potentially variable due to, e.g., the abundance of cell components or environmental conditions. To elevate the understanding of regulatory processes underlying the pattern formation it is crucial to quantitatively analyze the variability in naturally occurring patterns. Here, we review recent approaches toward characterization of noise on trichome initiation. We present methods for the quantification of spatial patterns, which are the basis for data-driven mathematical modeling and enable the analysis of noise from different sources. Besides the insight gained on trichome formation, the examination of observed trichome patterns also shows that highly regulated biological processes can be substantially affected by variability. PMID:25431575

  1. The hexanoyl-CoA precursor for cannabinoid biosynthesis is formed by an acyl-activating enzyme in Cannabis sativa trichomes.

    PubMed

    Stout, Jake M; Boubakir, Zakia; Ambrose, Stephen J; Purves, Randy W; Page, Jonathan E

    2012-08-01

    The psychoactive and analgesic cannabinoids (e.g. Δ(9) -tetrahydrocannabinol (THC)) in Cannabis sativa are formed from the short-chain fatty acyl-coenzyme A (CoA) precursor hexanoyl-CoA. Cannabinoids are synthesized in glandular trichomes present mainly on female flowers. We quantified hexanoyl-CoA using LC-MS/MS and found levels of 15.5 pmol g(-1) fresh weight in female hemp flowers with lower amounts in leaves, stems and roots. This pattern parallels the accumulation of the end-product cannabinoid, cannabidiolic acid (CBDA). To search for the acyl-activating enzyme (AAE) that synthesizes hexanoyl-CoA from hexanoate, we analyzed the transcriptome of isolated glandular trichomes. We identified 11 unigenes that encoded putative AAEs including CsAAE1, which shows high transcript abundance in glandular trichomes. In vitro assays showed that recombinant CsAAE1 activates hexanoate and other short- and medium-chained fatty acids. This activity and the trichome-specific expression of CsAAE1 suggest that it is the hexanoyl-CoA synthetase that supplies the cannabinoid pathway. CsAAE3 encodes a peroxisomal enzyme that activates a variety of fatty acid substrates including hexanoate. Although phylogenetic analysis showed that CsAAE1 groups with peroxisomal AAEs, it lacked a peroxisome targeting sequence 1 (PTS1) and localized to the cytoplasm. We suggest that CsAAE1 may have been recruited to the cannabinoid pathway through the loss of its PTS1, thereby redirecting it to the cytoplasm. To probe the origin of hexanoate, we analyzed the trichome expressed sequence tag (EST) dataset for enzymes of fatty acid metabolism. The high abundance of transcripts that encode desaturases and a lipoxygenase suggests that hexanoate may be formed through a pathway that involves the oxygenation and breakdown of unsaturated fatty acids. PMID:22353623

  2. Leaf trichome density may explain herbivory patterns of Actinote sp. (Lepidoptera: Acraeidae) on Liabum mandonii (Asteraceae) in a montane humid forest (Nor Yungas, Bolivia)

    NASA Astrophysics Data System (ADS)

    Molina-Montenegro, Marco A.; Ávila, Pamela; Hurtado, Rosember; Valdivia, Alejandra I.; Gianoli, Ernesto

    2006-09-01

    Increasing evidence shows that most insect herbivores of tropical forests show specific associations with their hosts. Environmental factors as well as foliar characters can modify insect preference. In the present work, we evaluated in a montane humid forest the preference and herbivory rate of Actinote sp. caterpillars (Lepidoptera: Acraeidae) on mature and young leaves of their specific host plant Liabum mandonii (Asteraceae) in two contrasting sites. Additionally, the density of non-glandular trichomes in young and mature leaves of plant at each site was evaluated. Analysis of variance of herbivory showed significant effects of site, leaf age, and the interaction of these factors. Higher herbivory levels were found on leaves from the site with lower levels of radiation and on mature leaves. On the other hand, trichome density was significantly higher in leaves from the site with higher levels of radiation and in young leaves. This suggests trichomes may explain the observed pattern of herbivory.

  3. Transcriptome profiling of trichome-less reveals genes associated with multicellular trichome development in Cucumis sativus.

    PubMed

    Zhao, Jun-Long; Wang, Yun-Li; Yao, Dan-Qing; Zhu, Wen-Ying; Chen, Long; He, Huan-Le; Pan, Jun-Song; Cai, Run

    2015-10-01

    Trichomes on plants, similar to fine hairs on animal and human bodies, play important roles in plant survival and development. They also represent a useful model for the study of cell differentiation. Although the regulatory gene network of unicellular trichome development in Arabidopsis thaliana has been well studied, the genes that regulate multicellular trichome development remain unclear. We confirmed that Cucumis sativus (cucumber) trichomes are multicellular and unbranched, but identified a spontaneous mutant, trichome-less (tril), which presented a completely glabrous phenotype. We compared the transcriptome profilings of the tril mutant and wild type using the Illumina HiSeq 2000 sequencing technology. A total of 991 genes exhibited differential expression: 518 were up-regulated and 473 were down-regulated. We further identified 62 differentially expressed genes that encoded crucial transcription factors and were subdivided into seven categories: homeodomain, MADS, MYB, and WRKY domains, ethylene-responsive, zinc finger, and other transcription factor genes. We further analyzed the tissue-expression profiles of two candidate genes, GLABRA2-like and ATHB51-like, using qRT-PCR and found that these two genes were specifically expressed in the epidermis and trichomes, respectively. These results and the tril mutant provide useful tools to study the molecular networks associated with multicellular trichome development. PMID:25952908

  4. Gene expression profile analysis of tobacco leaf trichomes

    PubMed Central

    2011-01-01

    Background Leaf trichomes of Nicotiana tabacum are distinguished by their large size, high density, and superior secretion ability. They contribute to plant defense response against biotic and abiotic stress, and also influence leaf aroma and smoke flavor. However, there is limited genomic information about trichomes of this non-model plant species. Results We have characterized Nicotiana tabacum leaf trichome gene expression using two approaches. In the first, a trichome cDNA library was randomly sequenced, and 2831 unique genes were obtained. The most highly abundant transcript was ribulose bisphosphate carboxylase (RuBisCO). Among the related sequences, most encoded enzymes involved in primary metabolism. Secondary metabolism related genes, such as isoprenoid and flavonoid biosynthesis-related, were also identified. In the second approach, a cDNA microarray prepared from these 2831 clones was used to compare gene expression levels in trichome and leaf. There were 438 differentially expressed genes between trichome and leaves-minus-trichomes. Of these, 207 highly expressed genes in tobacco trichomes were enriched in second metabolic processes, defense responses, and the metabolism regulation categories. The expression of selected unigenes was confirmed by semi-quantitative RT-PCR analysis, some of which were specifically expressed in trichomes. Conclusion The expression feature of leaf trichomes in Nicotiana tabacum indicates their metabolic activity and potential importance in stress resistance. Sequences predominantly expressed in trichomes will facilitate gene-mining and metabolism control of plant trichome. PMID:21548994

  5. Hop Shoot Proliferation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hop shoot proliferation disease has been described in Poland., and is associated with phytoplasma infection. Hop shoot proliferation occurs rarely and seems to be of little economic concern in most regions of hop production. Hop shoot proliferation is thought to be caused by aster yellows phytoplas...

  6. Analysis of purified glabra3-shapeshifter trichomes reveals a role for NOECK in regulating early trichome morphogenic events.

    PubMed

    Gilding, Edward K; Marks, M David

    2010-10-01

    Transcriptome analysis using the Affymetrix ATH1 platform has been completed on purified trichomes from the gl3-sst mutant. These trichomes display immature features, such as glassy cell walls and blunted branches. The gl3-sst trichome transcriptome was greatly enriched for genes involved in lipid biosynthesis, including those mediating the synthesis of fatty acids and wax. In addition, gl3-sst trichomes displayed reduced expression of the R3 MYBs TRY and CPC, which normally function to limit trichome development. The expression of the MIXTA-like MYB gene NOK was elevated. Members of the MIXTA-like family promote conical cell outgrowth, and in some cases, trichome initiation in diverse plant species. In contrast, NOK limits trichome outgrowth in wild-type Arabidopsis plants. Similar to other MIXTA-like genes, NOK was required for the expansion of gl3-sst trichomes, as the gl3-sst nok double mutant trichomes were greatly reduced in size. Expression of NOK in nok mutants reduced branch formation, whereas in gl3-sst nok, NOK expression promoted trichome cell outgrowth, illustrating duel roles for NOK in both promoting and limiting trichome development. MIXTA-like genes from phylogenetically diverse plant species could substitute for NOK in both nok and gl3-sst nok backgrounds. These findings suggest that certain aspects of NOK and MIXTA-like gene function have been conserved. PMID:21070410

  7. Proteomic snapshot of spearmint (Mentha spicata L.) leaf trichomes: a genuine terpenoid factory.

    PubMed

    Champagne, Antoine; Boutry, Marc

    2013-11-01

    Peltate glandular trichomes from Mentha spicata were purified on a Percoll gradient and soluble and membrane proteins were trypsinized and the peptides were separated by nano-LC fractionation and analyzed by MALDI-MS/MS. The vast majority of the 1666 proteins identified were housekeeping proteins or involved in the primary metabolism. However, 57 were predicted to be involved in the secondary metabolism. Of these, 21 were involved in the synthesis of phenylpropanoids and phenolics and 32 in terpenoid synthesis. Of the 14 membrane transporters identified, the 11 ATP-binding cassette transporters provide good material for assessing whether active transport is required for the transfer of monoterpenoid intermediates between cellular compartments and for the secretion of the final products into the subcuticular storage cavity. In conclusion, this proteome analysis of M. spicata peltate trichomes has identified several candidate proteins that might be involved in terpenoid synthesis and transport. The data have been deposited to the ProteomeXchange with identifier PXD000352 (http://proteomecentral.proteomexchange.org/dataset/PXD000352). PMID:24124164

  8. Studies of a Biochemical Factory: Tomato Trichome Deep Expressed Sequence Tag Sequencing and Proteomics1[W][OA

    PubMed Central

    Schilmiller, Anthony L.; Miner, Dennis P.; Larson, Matthew; McDowell, Eric; Gang, David R.; Wilkerson, Curtis; Last, Robert L.

    2010-01-01

    Shotgun proteomics analysis allows hundreds of proteins to be identified and quantified from a single sample at relatively low cost. Extensive DNA sequence information is a prerequisite for shotgun proteomics, and it is ideal to have sequence for the organism being studied rather than from related species or accessions. While this requirement has limited the set of organisms that are candidates for this approach, next generation sequencing technologies make it feasible to obtain deep DNA sequence coverage from any organism. As part of our studies of specialized (secondary) metabolism in tomato (Solanum lycopersicum) trichomes, 454 sequencing of cDNA was combined with shotgun proteomics analyses to obtain in-depth profiles of genes and proteins expressed in leaf and stem glandular trichomes of 3-week-old plants. The expressed sequence tag and proteomics data sets combined with metabolite analysis led to the discovery and characterization of a sesquiterpene synthase that produces β-caryophyllene and α-humulene from E,E-farnesyl diphosphate in trichomes of leaf but not of stem. This analysis demonstrates the utility of combining high-throughput cDNA sequencing with proteomics experiments in a target tissue. These data can be used for dissection of other biochemical processes in these specialized epidermal cells. PMID:20431087

  9. Compositions of essential oils and trichomes of Teucrium chamaedrys L. subsp. trapezunticum Rech. fil. and subsp. syspirense (C. Koch) Rech. fil.

    PubMed

    Kaya, Ayla; Demirci, Betül; Başer, K Hüsnü C

    2009-01-01

    Teucrium chamaedrys L. is a member of the Lamiaceae family and is represented in the Flora of Turkey by six subspecies. The aerial organs of T. chamaedrys L. subsp. trapezunticum Rech. fil. and subsp. syspirense (C. Koch) Rech. fil. bears numerous eglandular and glandular trichomes. Eglandular trichomes are simple, long-multicellular with cuticular micropapillae, and glandular hairs are of peltate and capitate types. The peltate hairs consist of a basal cell, a short unicellular stalk, and multicellular secretory head, and the capitate ones possess 1-2 stalk cells and one glandular head cell. The aerial parts were subjected to microdistillation for the isolation of volatiles. The analysis was simultaneously performed by using gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). The major components were characterized as beta-caryophyllene (18%), nonacosane (12%), germacrene D (11%), caryophyllene oxide (7%), and alpha-pinene (7%) for subsp. trapezunticum, and caryophyllene oxide (23%), alpha-pinene (11%), and caryophyllenol II (5%) for subsp. syspirense. PMID:19180459

  10. TEMPRANILLO Reveals the Mesophyll as Crucial for Epidermal Trichome Formation.

    PubMed

    Matías-Hernández, Luis; Aguilar-Jaramillo, Andrea E; Osnato, Michela; Weinstain, Roy; Shani, Eilon; Suárez-López, Paula; Pelaz, Soraya

    2016-03-01

    Plant trichomes are defensive specialized epidermal cells. In all accepted models, the epidermis is the layer involved in trichome formation, a process controlled by gibberellins (GAs) in Arabidopsis rosette leaves. Indeed, GA activates a genetic cascade in the epidermis for trichome initiation. Here we report that TEMPRANILLO (TEM) genes negatively control trichome initiation not only from the epidermis but also from the leaf layer underneath the epidermis, the mesophyll. Plants over-expressing or reducing TEM specifically in the mesophyll, display lower or higher trichome numbers, respectively. We surprisingly found that fluorescently labeled GA3 accumulates exclusively in the mesophyll of leaves, but not in the epidermis, and that TEM reduces its accumulation and the expression of several newly identified GA transporters. This strongly suggests that TEM plays an essential role, not only in GA biosynthesis, but also in regulating GA distribution in the mesophyll, which in turn directs epidermal trichome formation. Moreover, we show that TEM also acts as a link between GA and cytokinin signaling in the epidermis by negatively regulating downstream genes of both trichome formation pathways. Overall, these results call for a re-evaluation of the present theories of trichome formation as they reveal mesophyll essential during epidermal trichome initiation. PMID:26802039

  11. Modified branched-chain amino acid pathways give rise to acyl acids of sucrose esters exuded from tobacco leaf trichomes.

    PubMed

    Kandra, G; Severson, R; Wagner, G J

    1990-03-10

    A major diversion of carbon from branched-chain amino acid biosynthesis/catabolism to form acyl moieties of sucrose esters (6-O-acetyl-2,3,4-tri-O-acyl-alpha-D-glucopyranosyl-beta-D- fructofuranosides) was observed to be associated with specialized trichome head cells which secrete large amounts of sucrose esters. Surface chemistry and acetyl and acyl substituent groups of tobacco (T.I. 1068) sucrose esters were identified and quantified by gas chromatography/mass spectrometry. Sucrose esters were prominent surface constituents and 3-methylvaleric acid, 2- and 3-methylbutyric acid, and methylpropionic acid accounted for 60%, 25% and 9%, respectively, of total C3--C7 acyl substituents. Radiolabeled Thr, Ile, Val, Leu, pyruvate and Asp, metabolites of branched-chain amino acid pathways, were compared with radioactively labeled acetate and sucrose as donors of carbon to sucrose, acetyl and acyl components of sucrose esters using epidermal peels with undisturbed trichomes. Preparations of biosynthetically competent trichome heads (site of sucrose ester formation) were also examined. Results indicate that 3-methylvaleryl and 2-methylbutyryl groups are derived from the Thr pathway of branched-chain amino acid metabolism, 3-methylbutyryl and methylpropionyl groups are formed via the pyruvate pathway, and that acetyl groups are principally formed directly via acetyl-CoA. Arguments are presented which rule out participation of fatty acid synthase in the formation of prominent acyl acids. Results suggest that the shunting of carbon away from the biosynthesis of Val, Leu and Ile may be due to a low level of amino acid utilization in protein synthesis in specialized glandular head cells of trichomes. This would result in the availability of corresponding oxo acids for CoA activation and esterification to form sucrose esters. Preliminary evidence was found for the involvement of cycling reactions in oxo-acid-chain lengthening and for utilization of pyruvate-derived 2

  12. Coupling membranes as energy-transmitting cables. II. Cyanobacterial trichomes.

    PubMed

    Severina, I I; Skulachev, V P; Zorov, D B

    1988-08-01

    Power transmission along trichomes of filamentous cyanobacteria Phormidium uncinatum has been studied with the use of ethylrhodamine fluorescence as a probe for the transmembrane electric potential difference (delta psi). It is found that agents preventing the light-induced delta psi formation (photosynthetic redox chain inhibitor dibromothymoquinone) or dissipating delta psi (uncoupler tetrachlorotrifluoromethylbenzimidazole) strongly decrease the fluorescence of the ethyl-rhodamine-stained trichomes. K+-H+ antiporter nigericin converting delta pH to delta psi increases the fluorescence. These relationships are in agreement with the assumption that ethylrhodamine electrophoretically accumulates inside the cyanobacterial cells. Illumination of a single cell in the P. uncinatum trichome gives rise to quenching of the fluorescence in this cell and usually in one or two neighbor cells, whereas the rest of trichome remains fluorescing. A small light spot (5% of the trichome length) causes an increase in the ethylrhodamine fluorescence not only in the illuminated but also in the nonilluminated parts of the trichome up to the laser-treated cell or its neighbor(s). It is concluded ethylrhodamine can be used to monitor the power transmission which was previously demonstrated by microelectrode studies of the cyanobacterial trichomes. In certain trichomes, several "dark" cells appear during the storage of the trichomes without energy sources. Illumination for several minutes results in dark cells becoming fluorescing. Thus some cells or cell clusters can be reversibly excluded from the lateral delta psi-transmitting system of the trichome, the rest being still electrically connected. This means that filamentous cyanobacteria possess mechanisms to transmit power along the trichome and to switch off this transmission. PMID:3138245

  13. Trichome-Related Mutants Provide a New Perspective on Multicellular Trichome Initiation and Development in Cucumber (Cucumis sativus L)

    PubMed Central

    Liu, Xingwang; Bartholomew, Ezra; Cai, Yanling; Ren, Huazhong

    2016-01-01

    Trichomes are specialized epidermal cells located in aerial parts of plants that function in plant defense against biotic and abiotic stresses. The simple unicellular trichomes of Arabidopsis serve as an excellent model to study the molecular mechanism of cell differentiation and pattern formation in plants. Loss-of-function mutations in Arabidopsis thaliana have suggested that the core genes GL1 (which encodes a MYB transcription factor) and TTG1 (which encodes a WD40 repeat-containing protein) are important for the initiation and spacing of leaf trichomes, while for normal trichome initiation, the genes GL3, and EGL3 (which encode a bHLH protein) are needed. However, the positive regulatory genes involved in multicellular trichrome development in cucumber remain unclear. This review focuses on the phenotype of mutants (csgl3, tril, tbh, mict, and csgl1) with disturbed trichomes in cucumber and then infers which gene(s) play key roles in trichome initiation and development in those mutants. Evidence indicates that MICT, TBH, and CsGL1 are allelic with alternative splicing. CsGL3 and TRIL are allelic and override the effect of TBH, MICT, and CsGL1 on the regulation of multicellular trichome development; and affect trichome initiation. CsGL3, TRIL, MICT, TBH, and CsGL1 encode HD-Zip proteins with different subfamilies. Genetic and molecular analyses have revealed that CsGL3, TRIL, MICT, TBH, and CsGL1 are responsible for the differentiation of epidermal cells and the development of trichomes. Based on current knowledge, a positive regulator pathway model for trichome development in cucumber was proposed and compared to a model in Arabidopsis. These data suggest that trichome development in cucumber may differ from that in Arabidopsis. PMID:27559338

  14. Trichome-Related Mutants Provide a New Perspective on Multicellular Trichome Initiation and Development in Cucumber (Cucumis sativus L).

    PubMed

    Liu, Xingwang; Bartholomew, Ezra; Cai, Yanling; Ren, Huazhong

    2016-01-01

    Trichomes are specialized epidermal cells located in aerial parts of plants that function in plant defense against biotic and abiotic stresses. The simple unicellular trichomes of Arabidopsis serve as an excellent model to study the molecular mechanism of cell differentiation and pattern formation in plants. Loss-of-function mutations in Arabidopsis thaliana have suggested that the core genes GL1 (which encodes a MYB transcription factor) and TTG1 (which encodes a WD40 repeat-containing protein) are important for the initiation and spacing of leaf trichomes, while for normal trichome initiation, the genes GL3, and EGL3 (which encode a bHLH protein) are needed. However, the positive regulatory genes involved in multicellular trichrome development in cucumber remain unclear. This review focuses on the phenotype of mutants (csgl3, tril, tbh, mict, and csgl1) with disturbed trichomes in cucumber and then infers which gene(s) play key roles in trichome initiation and development in those mutants. Evidence indicates that MICT, TBH, and CsGL1 are allelic with alternative splicing. CsGL3 and TRIL are allelic and override the effect of TBH, MICT, and CsGL1 on the regulation of multicellular trichome development; and affect trichome initiation. CsGL3, TRIL, MICT, TBH, and CsGL1 encode HD-Zip proteins with different subfamilies. Genetic and molecular analyses have revealed that CsGL3, TRIL, MICT, TBH, and CsGL1 are responsible for the differentiation of epidermal cells and the development of trichomes. Based on current knowledge, a positive regulator pathway model for trichome development in cucumber was proposed and compared to a model in Arabidopsis. These data suggest that trichome development in cucumber may differ from that in Arabidopsis. PMID:27559338

  15. Are plant trichomes harmful to predatory insects and mites?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plants may use epidermal hairs (trichomes) to defend themselves from attack by herbivores. Predatory arthropods may serve as biocontrol agents against herbivores. Whether or not plant trichomes work in concert with predators is undocumented in many cases. We reviewed the peer-reviewed literature ...

  16. Plant trichomes have mixed impacts on predatory insects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In response to our review article on the role of plant trichomes on insect predators (Riddick & Simmons 2014), Krimmel (2014) acknowledged the challenges that are faced in bringing together the varied publications on the subject of impact of plant trichomes on predatory insects. He also suggested t...

  17. Wheeled hopping robot

    SciTech Connect

    Fischer, Gary J.

    2010-08-17

    The present invention provides robotic vehicles having wheeled and hopping mobilities that are capable of traversing (e.g. by hopping over) obstacles that are large in size relative to the robot and, are capable of operation in unpredictable terrain over long range. The present invention further provides combustion powered linear actuators, which can include latching mechanisms to facilitate pressurized fueling of the actuators, as can be used to provide wheeled vehicles with a hopping mobility.

  18. Acylsugar Acylhydrolases: Carboxylesterase-Catalyzed Hydrolysis of Acylsugars in Tomato Trichomes.

    PubMed

    Schilmiller, Anthony L; Gilgallon, Karin; Ghosh, Banibrata; Jones, A Daniel; Last, Robert L

    2016-03-01

    Glandular trichomes of cultivated tomato (Solanum lycopersicum) and many other species throughout the Solanaceae produce and secrete mixtures of sugar esters (acylsugars) on the plant aerial surfaces. In wild and cultivated tomato, these metabolites consist of a sugar backbone, typically glucose or sucrose, and two to five acyl chains esterified to various positions on the sugar core. The aliphatic acyl chains vary in length and branching and are transferred to the sugar by a series of reactions catalyzed by acylsugar acyltransferases. A phenotypic screen of a set of S. lycopersicum M82 × Solanum pennellii LA0716 introgression lines identified a dominant genetic locus on chromosome 5 from the wild relative that affected total acylsugar levels. Genetic mapping revealed that the reduction in acylsugar levels was consistent with the presence and increased expression of two S. pennellii genes (Sopen05g030120 and Sopen05g030130) encoding putative carboxylesterase enzymes of the α/β-hydrolase superfamily. These two enzymes, named ACYLSUGAR ACYLHYDROLASE1 (ASH1) and ASH2, were shown to remove acyl chains from specific positions of certain types of acylsugars in vitro. A survey of related genes in M82 and LA0716 identified another trichome-expressed ASH gene on chromosome 9 (M82, Solyc09g075710; LA0716, Sopen09g030520) encoding a protein with similar activity. Characterization of the in vitro activities of the SpASH enzymes showed reduced activities with acylsugars produced by LA0716, presumably contributing to the high-level production of acylsugars in the presence of highly expressed SpASH genes. PMID:26811191

  19. Acylsugar Acylhydrolases: Carboxylesterase-Catalyzed Hydrolysis of Acylsugars in Tomato Trichomes1[OPEN

    PubMed Central

    Gilgallon, Karin; Ghosh, Banibrata

    2016-01-01

    Glandular trichomes of cultivated tomato (Solanum lycopersicum) and many other species throughout the Solanaceae produce and secrete mixtures of sugar esters (acylsugars) on the plant aerial surfaces. In wild and cultivated tomato, these metabolites consist of a sugar backbone, typically glucose or sucrose, and two to five acyl chains esterified to various positions on the sugar core. The aliphatic acyl chains vary in length and branching and are transferred to the sugar by a series of reactions catalyzed by acylsugar acyltransferases. A phenotypic screen of a set of S. lycopersicum M82 × Solanum pennellii LA0716 introgression lines identified a dominant genetic locus on chromosome 5 from the wild relative that affected total acylsugar levels. Genetic mapping revealed that the reduction in acylsugar levels was consistent with the presence and increased expression of two S. pennellii genes (Sopen05g030120 and Sopen05g030130) encoding putative carboxylesterase enzymes of the α/β-hydrolase superfamily. These two enzymes, named ACYLSUGAR ACYLHYDROLASE1 (ASH1) and ASH2, were shown to remove acyl chains from specific positions of certain types of acylsugars in vitro. A survey of related genes in M82 and LA0716 identified another trichome-expressed ASH gene on chromosome 9 (M82, Solyc09g075710; LA0716, Sopen09g030520) encoding a protein with similar activity. Characterization of the in vitro activities of the SpASH enzymes showed reduced activities with acylsugars produced by LA0716, presumably contributing to the high-level production of acylsugars in the presence of highly expressed SpASH genes. PMID:26811191

  20. Hopping Robot with Wheels

    NASA Technical Reports Server (NTRS)

    Barlow, Edward; Marzwell, Nevellie; Fuller, Sawyer; Fionni, Paolo; Tretton, Andy; Burdick, Joel; Schell, Steve

    2003-01-01

    A small prototype mobile robot is capable of (1) hopping to move rapidly or avoid obstacles and then (2) moving relatively slowly and precisely on the ground by use of wheels in the manner of previously reported exploratory robots of the "rover" type. This robot is a descendant of a more primitive hopping robot described in "Minimally Actuated Hopping Robot" (NPO- 20911), NASA Tech Briefs, Vol. 26, No. 11 (November 2002), page 50. There are many potential applications for robots with hopping and wheeled-locomotion (roving) capabilities in diverse fields of endeavor, including agriculture, search-and-rescue operations, general military operations, removal or safe detonation of land mines, inspection, law enforcement, and scientific exploration on Earth and remote planets. The combination of hopping and roving enables this robot to move rapidly over very rugged terrain, to overcome obstacles several times its height, and then to position itself precisely next to a desired target. Before a long hop, the robot aims itself in the desired hopping azimuth and at a desired takeoff angle above horizontal. The robot approaches the target through a series of hops and short driving operations utilizing the steering wheels for precise positioning.

  1. Hop Cultivars and Breeding

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pest management decision making in hops varies among cultivars. Historically, the primary objective of hop breeding programs has been to increase the yield or characteristics associated with either bittering (high alpha-acids) or aroma (unique volatile oil profiles) cultivars. Other factors consid...

  2. Functionally Divergent Alleles and Duplicated Loci Encoding an Acyltransferase Contribute to Acylsugar Metabolite Diversity in Solanum Trichomes[OPEN

    PubMed Central

    Schilmiller, Anthony L.; Moghe, Gaurav D.; Fan, Pengxiang; Ghosh, Banibrata; Ning, Jing; Jones, A. Daniel; Last, Robert L.

    2015-01-01

    Glandular trichomes from tomato (Solanum lycopersicum) and other species in the Solanaceae produce and secrete a mixture of O-acylsugars (aliphatic esters of sucrose and glucose) that contribute to insect defense. Despite their phylogenetic distribution and diversity, relatively little is known about how these specialized metabolites are synthesized. Mass spectrometric profiling of acylsugars in the S. lycopersicum x Solanum pennellii introgression lines identified a chromosome 11 locus containing a cluster of BAHD acyltransferases with one gene (named Sl-ASAT3) expressed in tip cells of type I trichomes where acylsugars are made. Sl-ASAT3 was shown to encode an acyl-CoA-dependent acyltransferase that catalyzes the transfer of short (four to five carbons) branched acyl chains to the furanose ring of di-acylsucrose acceptors to produce tri-acylsucroses, which can be further acetylated by Sl-ASAT4 (previously Sl-AT2). Among the wild tomatoes, diversity in furanose ring acyl chains on acylsucroses was most striking in Solanum habrochaites. S. habrochaites accessions from Ecuador and northern Peru produced acylsucroses with short (≤C5) or no acyl chains on the furanose ring. Accessions from central and southern Peru had the ability to add short or long (up to C12) acyl chains to the furanose ring. Multiple ASAT3-like sequences were found in most accessions, and their in vitro activities correlated with observed geographical diversity in acylsugar profiles. PMID:25862303

  3. Trichomes control flower bud shape by linking together young petals.

    PubMed

    Tan, Jiafu; Walford, Sally-Anne; Dennis, Elizabeth S; Llewellyn, Danny

    2016-01-01

    Trichomes are widespread in plants and develop from surface cells on different tissues(1). They have many forms and functions, from defensive spines to physical barriers that trap layers of air to insulate against desiccation, but there is growing evidence that trichomes can also have developmental roles in regulating flower structure(2,3). We report here that the trichomes on petals of cotton, Gossypium hirsutum L., are essential for correct flower bud shape through a mechanical entanglement of the trichomes on adjacent petals that anchor the edges to counter the opposing force generated by asymmetric expansion of overlapping petals. Silencing a master regulator of petal trichomes, GhMYB-MIXTA-Like10 (GhMYBML10), by RNA interference (RNAi) suppressed petal trichome growth and resulted in flower buds forming into abnormal corkscrew shapes that exposed developing anthers and stigmas to desiccation damage. Artificially gluing petal edges together could partially restore correct bud shape and fertility. Such petal 'Velcro' is present in other Malvaceae and perhaps more broadly in other plant families, although it is not ubiquitous. This mechanism for physical association between separate organs to regulate flower shape and function is different from the usual organ shape control(4) exerted through cell-to-cell communication and differential cell expansion within floral tissues(5,6). PMID:27322517

  4. The lunar hopping transporter

    NASA Technical Reports Server (NTRS)

    Degner, R.; Kaplan, M. H.; Manning, J.; Meetin, R.; Pasternack, S.; Peterson, S.; Seifert, H.

    1971-01-01

    Research on several aspects of lunar transport using the hopping mode is reported. Hopping exploits the weak lunar gravity, permits fuel economy because of partial recompression of propellant gas on landing, and does not require a continuous smooth surface for operation. Three questions critical to the design of a lunar hopping vehicle are addressed directly in this report: (1) the tolerance of a human pilot for repeated accelerations; (2) means for controlling vehicle attitude during ballistic flight; and (3) means of propulsion. In addition, a small scale terrestrial demonstrator built to confirm feasibility of the proposed operational mode is described, along with results of preliminary study of unmanned hoppers for moon exploration.

  5. Glandular Odontogenic Cyst of the Anterior Mandible

    PubMed Central

    Raju, Srinivasa Pathapati; Reddy, Sridhar Padala; Ananthnag, Jakkula

    2015-01-01

    Context: Glandular odontogenic cyst (GOC) is a rare cyst occurring in the middle-age people with mandibular anterior as the common site of occurrence. Case Report: We report a case of massive GOC in a 65-year-old female with an emphasis on its clinical course, histological features, and treatment modalities. Conclusion: The aggressiveness and recurrences of GOC warrants clinicians for the careful examination, treatment, and long-term follow-up. PMID:25789251

  6. Inflammatory and glandular skin disease in pregnancy.

    PubMed

    Yang, Catherine S; Teeple, Mary; Muglia, Jennie; Robinson-Bostom, Leslie

    2016-01-01

    A switch from cell-mediated to humoral immunity (helper T 1 [Th1] to helper T 2 [Th2] shift) during gestation plays a key role in placental immune tolerance. As a result, skin diseases that are Th2 mediated often worsen, whereas skin diseases that are Th1 mediated often improve during gestation. Also, due to fluctuations in glandular activity, skin diseases involving sebaceous and eccrine glands may flare, whereas those involving apocrine glands may improve during pregnancy. Despite these trends, inflammatory and glandular skin diseases do not always follow the predicted pattern, and courses are often diverse. We review the gestational course of inflammatory skin diseases, such as atopic dermatitis (atopic eruption of pregnancy), psoriasis, impetigo herpetiformis, urticaria, erythema annulare centrifugum, pityriasis rosea, sarcoidosis, Sweet syndrome, and erythema nodosum, as well as glandular skin diseases, including acne vulgaris, acne rosacea, perioral dermatitis, hidradenitis suppurativa, Fox-Fordyce disease, hyperhidrosis, and miliaria. For each of these diseases, we discuss the pathogenesis, clinical presentation, and management with special consideration for maternal and fetal safety. PMID:27265071

  7. Clade-specific positive selection on a developmental gene: BRANCHLESS TRICHOME and the evolution of stellate trichomes in Physaria (Brassicaceae).

    PubMed

    Mazie, Abigail R; Baum, David A

    2016-07-01

    Positive selection is known to drive the evolution of genes involved in evolutionary arms races, but what role does it play in the evolution of genes involved in developmental processes? We used the single-celled epidermal trichomes of Brassicaceae as a model to uncover the molecular evolutionary processes that contributed to the transition from dendritic trichomes, as seen in most species of Brassicaceae, to the distinctive stellate trichomes of the genus Physaria. We explored the role of positive selection on the evolution of BRANCHLESS TRICHOME (BLT), a candidate gene for changes in trichome branching pattern. Maximum likelihood models of codon evolution point to a shift in selective pressure affecting the evolution of BLT across the entire Physaria clade, and we found strong evidence that positive selection has acted on a subset of Physaria BLT codons. Almost all of the 10 codon sites with the highest probability of having evolved under positive selection are clustered in a predicted coiled-coil domain, pointing to changes in protein-protein interactions. Thus, our findings suggest that selection acted on BLT to modify its interactions with other proteins. The fact that positive selection occurred throughout the radiation of Physaria could reflect selection to stabilize development in response to an abrupt switch from the dendritic form to the stellate form, divergent selection for diversification of the stellate form, or both. These results point to the need for evolutionary developmental studies of BLT and its interacting proteins in Physaria. PMID:27015897

  8. Surface Hopping by Consensus.

    PubMed

    Martens, Craig C

    2016-07-01

    We present a new stochastic surface hopping method for modeling molecular dynamics with electronic transitions. The approach, consensus surface hopping (CSH), is a numerical framework for solving the semiclassical limit Liouville equation describing nuclear dynamics on coupled electronic surfaces using ensembles of trajectories. In contrast to existing techniques based on propagating independent classical trajectories that undergo stochastic hops between the electronic states, the present method determines the probabilities of transition of each trajectory collectively with input from the entire ensemble. The full coherent dynamics of the coupled system arise naturally at the ensemble level and ad hoc corrections, such as momentum rescaling to impose strict trajectory energy conservation and artificial decoherence to avoid the overcoherence of the quantum states associated with independent trajectories, are avoided. PMID:27345103

  9. Differential expression of trichomes on the leaves of upland cotton (Gossypium hirsutum L)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study evaluated and quantified trichome diversity on various cotton lines. Leaf trichomes were evaluated with scanning electron and light microscopy on fixed and live samples. Observations indicated that trichome complexity and quantity increased on the mainstem leaves as sampling progressed ...

  10. SIAMESE, a gene controlling the endoreduplication cell cycle in Arabidopsis thaliana trichomes.

    PubMed

    Walker, J D; Oppenheimer, D G; Concienne, J; Larkin, J C

    2000-09-01

    Cell differentiation is generally tightly coordinated with the cell cycle, typically resulting in a nondividing cell with a unique differentiated morphology. The unicellular trichomes of Arabidopsis are a well-established model for the study of plant cell differentiation. Here, we describe a new genetic locus, SIAMESE (SIM), required for coordinating cell division and cell differentiation during the development of Arabidopsis trichomes (epidermal hairs). A recessive mutation in the sim locus on chromosome 5 results in clusters of adjacent trichomes that appeared to be morphologically identical 'twins'. Upon closer inspection, the sim mutant was found to produce multicellular trichomes in contrast to the unicellular trichomes produced by wild-type (WT) plants. Mutant trichomes consisting of up to 15 cells have been observed. Scanning electron microscopy of developing sim trichomes suggests that the cell divisions occur very early in the development of mutant trichomes. WT trichome nuclei continue to replicate their DNA after mitosis and cytokinesis have ceased, and as a consequence have a DNA content much greater than 2C. This phenomenon is known as endoreduplication. Individual nuclei of sim trichomes have a reduced level of endoreduplication relative to WT trichome nuclei. Endoreduplication is also reduced in dark-grown sim hypocotyls relative to WT, but not in light-grown hypocotyls. Double mutants of sim with either of two other mutants affecting endoreduplication, triptychon (try) and glabra3 (gl3) are consistent with a function for SIM in endoreduplication. SIM may function as a repressor of mitosis in the endoreduplication cell cycle. Additionally, the relatively normal morphology of multicellular sim trichomes indicates that trichome morphogenesis can occur relatively normally even when the trichome precursor cell continues to divide. The sim mutant phenotype also has implications for the evolution of multicellular trichomes. PMID:10952891

  11. Registration of 'Teamaker' Hop

    Technology Transfer Automated Retrieval System (TEKTRAN)

    'Teamaker' is a new hop (Humulus lupulus L.) variety exhibiting high beta-acids and near-zero alpha acids soft resins contents, a unique situation in the Humulus species. Teamaker arose as a selection from the cross, USDA 19105 x USDA 19046M, and as such has the genetic composition of 5/16th Fuggle...

  12. Disposition of hop prenylflavonoids in human breast tissue

    PubMed Central

    Bolca, Selin; Li, Jinghu; Nikolic, Dejan; Roche, Nathalie; Blondeel, Phillip; Possemiers, Sam; De Keukeleire, Denis; Bracke, Marc; Heyerick, Arne; van Breemen, Richard B.; Depypere, Herman

    2013-01-01

    Hop-derived products may contain xanthohumol (XN), isoxanthohumol (IX), and the potent phytoestrogen 8-prenylnaringenin (8-PN). To evaluate the potential health effects of these prenylflavonoids on breast tissue, their concentration, nature of metabolites, and biodistribution were assessed and compared to 17β-estradiol (E2) exposure. In this dietary intervention study, women were randomly allocated to hop (n=11; 2.04 mg XN, 1.20 mg IX, and 0.1 mg 8-PN per supplement) or control (n=10). After a run-in of ≥4d, 3 supplements were taken daily during 5d preceding an aesthetic breast reduction. Blood and breast biopsies were analyzed using HPLC-ESI-MS/MS. Upon hop administration, XN and IX concentrations ranged between 0.72–17.65 nmol/L and 3.30–31.50 nmol/L, and between 0.26– 5.14 pmol/g and 1.16–83.67 pmol/g in hydrolyzed serum and breast tissue, respectively. 8-PN however, was only detected in samples of moderate and strong 8-PN producers (0.43–7.06 nmol/L and 0.78–4.83 pmol/g). Phase I metabolism appeared to be minor (~10%), whereas extensive glucuronidation was observed (>90%). Total prenylflavonoids showed a breast adipose/glandular tissue distribution of 38/62 and their derived E2-equivalents were negligible compared to E2 in adipose (384.6±118.8 fmol/g, P=0.009) and glandular (241.6±93.1 fmol/g, P<0.001) tissue, respectively. Consequently, low doses of prenylflavonoids are unlikely to elicit estrogenic responses in breast tissue. PMID:20486208

  13. Disposition of hop prenylflavonoids in human breast tissue.

    PubMed

    Bolca, Selin; Li, Jinghu; Nikolic, Dejan; Roche, Nathalie; Blondeel, Phillip; Possemiers, Sam; De Keukeleire, Denis; Bracke, Marc; Heyerick, Arne; van Breemen, Richard B; Depypere, Herman

    2010-07-01

    Hop-derived products may contain xanthohumol (XN), isoxanthohumol (IX), and the potent phytoestrogen 8-prenylnaringenin (8-PN). To evaluate the potential health effects of these prenylflavonoids on breast tissue, their concentration, nature of metabolites, and biodistribution were assessed and compared with 17beta-estradiol (E(2)) exposure. In this dietary intervention study, women were randomly allocated to hop (n=11; 2.04 mg XN, 1.20 mg IX, and 0.1 mg 8-PN per supplement) or control (n=10). After a run-in of >or=4 days, three supplements were taken daily for 5 days preceding an aesthetic breast reduction. Blood and breast biopsies were analyzed using HPLC-ESI-MS/MS. Upon hop administration, XN and IX concentrations ranged between 0.72 and 17.65 nmol/L and 3.30 and 31.50 nmol/L, and between 0.26 and 5.14 pmol/g and 1.16 and 83.67 pmol/g in hydrolyzed serum and breast tissue, respectively. 8-PN however, was only detected in samples of moderate and strong 8-PN producers (0.43-7.06 nmol/L and 0.78-4.83 pmol/g). Phase I metabolism appeared to be minor (approximately 10%), whereas extensive glucuronidation was observed (> 90%). Total prenylflavonoids showed a breast adipose/glandular tissue distribution of 38/62 and their derived E(2)-equivalents were negligible compared with E(2) in adipose (384.6+/-118.8 fmol/g, p=0.009) and glandular (241.6+/-93.1 fmol/g, p<0.001) tissue, respectively. Consequently, low doses of prenylflavonoids are unlikely to elicit estrogenic responses in breast tissue. PMID:20486208

  14. Glandular odontogenic cyst: A diagnostic dilemma.

    PubMed

    Shah, Amisha A; Sangle, Amit; Bussari, Smita; Koshy, Ajit V

    2016-01-01

    Glandular odontogenic cyst (GOC) is a rare and uncommon jaw bone cyst of odontogenic origin described in 1987 by Gardener et al. as a distinct entity. It is a cyst having an unpredictable, potentially aggressive behavior, and has the propensity to grow in large size with relatively high recurrence rate. It poses a diagnostic challenge as it can be clinically and histopathologically confused with lateral periodontal cyst, botryoid odontogenic cyst, radicular and residual cysts with mucous metaplasia, and low-grade mucoepidermoid carcinoma. The present case report describes GOC in both male and female patients with intra-oral swelling following extraction of 36 and 46, respectively. Careful histopathological examination is needed to diagnose GOC, and a careful long-term follow-up is advocated. PMID:27134453

  15. Glandular odontogenic cyst: A diagnostic dilemma

    PubMed Central

    Shah, Amisha A.; Sangle, Amit; Bussari, Smita; Koshy, Ajit V.

    2016-01-01

    Glandular odontogenic cyst (GOC) is a rare and uncommon jaw bone cyst of odontogenic origin described in 1987 by Gardener et al. as a distinct entity. It is a cyst having an unpredictable, potentially aggressive behavior, and has the propensity to grow in large size with relatively high recurrence rate. It poses a diagnostic challenge as it can be clinically and histopathologically confused with lateral periodontal cyst, botryoid odontogenic cyst, radicular and residual cysts with mucous metaplasia, and low-grade mucoepidermoid carcinoma. The present case report describes GOC in both male and female patients with intra-oral swelling following extraction of 36 and 46, respectively. Careful histopathological examination is needed to diagnose GOC, and a careful long-term follow-up is advocated. PMID:27134453

  16. Glandular odontogenic cyst: A case report

    PubMed Central

    Karjodkar, Freny R.; Yadav, Archana; Sansare, Kaustubh; Sontakke, Subodh

    2014-01-01

    Glandular odontogenic cysts (GOCs) are rare intrabony solitary or multiloculated cysts of odontogenic origin. The importance of GOCs lies in the fact that they exhibit a propensity for recurrence similar to keratocystic odontogenic tumors and that they may be confused microscopically with central mucoepidermoid carcinoma. Thus, the oral and maxillofacial radiologists play an important role in definitive diagnosis of GOC based on distinctive cases; though they are rare. In large part, this is due to the GOC's complex and frequently non-specific histopathology. This report describes a case of GOC occurrence in the posterior mandibular ramus region in a 17-year-old female, which is a rare combination of site, age, and gender for occurrence. PMID:24701462

  17. Effect of gibberellic acid and calliterpenone on plant growth attributes, trichomes, essential oil biosynthesis and pathway gene expression in differential manner in Mentha arvensis L.

    PubMed

    Bose, Subir K; Yadav, Ritesh Kumar; Mishra, Smrati; Sangwan, Rajender S; Singh, A K; Mishra, B; Srivastava, A K; Sangwan, Neelam S

    2013-05-01

    Extensive research is going on throughout the world to find out new molecules from natural sources to be used as plant growth promoter. Mentha arvensis L. is the main source of menthol rich essential oil used commercially in various food, pharmaceutical and other preparations. Experiments were conducted on field grown plants for understanding the effect of calliterpenone (CA), a stereo-isomer of abbeokutone, in comparison to gibberellic acid (GA3) on growth attributes, trichomes, essential oil biosynthesis and expression of some oil biosynthetic pathway genes. The exogenous application of CA (1 μM, 10 μM and 100 μM) was found to be better in improving plant biomass and stolon yield, leaf area, branching and leaf stem ratio than with counterpart GA3 at the same concentrations. CA treated plants showed higher glandular trichome number, density and diameter and also correlated with enhanced oil biogenetic capacity as revealed by feeding labeled (14)C-sucrose for 72 h to excised shoots. Semi-quantitative PCR analysis of key pathway genes revealed differential up regulation under CA treatments. Transcript level of menthol dehydrogenase/menthone reductase was found highly up regulated in CA treated plants with increased content of menthone and menthol in oil. These findings demonstrate that CA positively regulated the yields by enhanced branching and higher density of trichomes resulting into higher accumulation of essential oil. The results suggest CA as a novel plant derived diterpenoid with growth promoting action and opens up new possibilities for improving the crop yields and essential oil biosynthesis in qualitative and quantitative manner. PMID:23514759

  18. Chlamydia muridarum Induction of Glandular Duct Dilation in Mice

    PubMed Central

    Sun, Xin; Yang, Zhangsheng; Zhang, Hongbo; Dai, Jin; Chen, Jianlin; Tang, Lingli; Rippentrop, Sheena; Xue, Min

    2015-01-01

    Although Chlamydia-induced hydrosalpinx in women and mice has been used as a surrogate marker for tubal infertility, the medical relevance of nontubal pathologies, such as uterine horn dilation, developed in mice following chlamydial infection remains unclear. We now report that the uterine horn dilation correlates with glandular duct dilation detected microscopically following Chlamydia muridarum infection. The dilated glandular ducts pushed the uterine horn lumen to closure or dilation and even broke through the myometrium to develop extrusion outside the uterine horn. The severity scores of uterine horn dilation observed macroscopically correlated well with the number of cross sections of the dilated glandular ducts counted under microscopy. Chlamydial infection was detected in the glandular epithelial cells, potentially leading to inflammation and dilation of the glandular ducts. Direct delivery of C. muridarum into the mouse uterus increased both uterine horn/glandular duct dilation and hydrosalpinx. However, the chlamydial plasmid, which is essential for the induction of hydrosalpinx, was not required for the induction of uterine horn/glandular duct dilation. Screening 12 strains of mice for uterine horn dilation following C. muridarum infection revealed that B10.D2, C57BL/10J, and C57BL/6J mice were most susceptible, followed by BALB/cJ and A/J mice. Deficiency in host genes involved in immune responses failed to significantly alter the C. muridarum induction of uterine horn dilation. Nevertheless, the chlamydial induction of uterine horn/glandular duct dilation may be used to evaluate plasmid-independent pathogenicity of Chlamydia in susceptible mice. PMID:25824829

  19. Variation in vegetative growth and trichomes in Cannabis sativa L. (Marihuana) in response to enviromental pollution

    SciTech Connect

    Sharma, G.K.; Mann, S.K.

    1984-07-01

    Four populations of Cannabis sativa L. (marihuana) growing in their native habitat and exposed to different levels of environmental pollution were studied for several leaf morphology and leaf trichome features. Leaf length, petiole length, length and width of central leaflet, and the number of teeth on leaf margin decreased with increase in pollution. Trichome length and trichome density values were found to be higher in populations exposed to higher levels of environmental pollution.

  20. Dosimetric implications of age related glandular changes in screening mammography

    NASA Astrophysics Data System (ADS)

    Beckett, J. R.; Kotre, C. J.

    2000-03-01

    The UK National Health Service Breast Screening Programme is currently organized to routinely screen women between the ages of 50 and 64, with screening for older women available on request. The lower end of this age range closely matches the median age for the menopause (51 years), during which significant changes in the composition of the breast are known to occur. In order to quantify the dosimetric effect of these changes, radiographic factors and compressed breast thickness data for a cohort of 1258 women aged between 35 and 79 undergoing breast screening mammography have been used to derive estimates of breast glandularity and mean glandular dose (MGD), and examine their variation with age. The variation of mean radiographic exposure factors with age is also investigated. The presence of a significant number of age trial women within the cohort allowed an extended age range to be studied. Estimates of MGD including corrections for breast glandularity based on compressed breast thickness only, compressed breast thickness and age and for each individual woman are compared with the MGD based on the conventional assumption of a 50:50 adipose/glandular composition. It has been found that the use of the conventional 50:50 assumption leads to overestimates of MGD of up to 13% over the age range considered. By using compressed breast thickness to estimate breast glandularity, this error range can be reduced to 8%, whilst age and compressed breast thickness based glandularity estimates result in an error range of 1%.

  1. TEMPRANILLO Reveals the Mesophyll as Crucial for Epidermal Trichome Formation1[OPEN

    PubMed Central

    Aguilar-Jaramillo, Andrea E.; Osnato, Michela; Shani, Eilon

    2016-01-01

    Plant trichomes are defensive specialized epidermal cells. In all accepted models, the epidermis is the layer involved in trichome formation, a process controlled by gibberellins (GAs) in Arabidopsis rosette leaves. Indeed, GA activates a genetic cascade in the epidermis for trichome initiation. Here we report that TEMPRANILLO (TEM) genes negatively control trichome initiation not only from the epidermis but also from the leaf layer underneath the epidermis, the mesophyll. Plants over-expressing or reducing TEM specifically in the mesophyll, display lower or higher trichome numbers, respectively. We surprisingly found that fluorescently labeled GA3 accumulates exclusively in the mesophyll of leaves, but not in the epidermis, and that TEM reduces its accumulation and the expression of several newly identified GA transporters. This strongly suggests that TEM plays an essential role, not only in GA biosynthesis, but also in regulating GA distribution in the mesophyll, which in turn directs epidermal trichome formation. Moreover, we show that TEM also acts as a link between GA and cytokinin signaling in the epidermis by negatively regulating downstream genes of both trichome formation pathways. Overall, these results call for a re-evaluation of the present theories of trichome formation as they reveal mesophyll essential during epidermal trichome initiation. PMID:26802039

  2. GLABROUS INFLORESCENCE STEMS regulates trichome branching by genetically interacting with SIM in Arabidopsis.

    PubMed

    Sun, Li-Li; Zhou, Zhong-Jing; An, Li-Jun; An, Yan; Zhao, Yong-Qin; Meng, Xiao-Fang; Steele-King, Clare; Gan, Yin-Bo

    2013-07-01

    Arabidopsis trichomes are large branched single cells that protrude from the epidermis. The first morphological indication of trichome development is an increase in nuclear content resulting from an initial cycle of endoreduplication. Our previous study has shown that the C2H2 zinc finger protein GLABROUS INFLORESCENCE STEMS (GIS) is required for trichome initiation in the inflorescence organ and for trichome branching in response to gibberellic acid signaling, although GIS gene does not play a direct role in regulating trichome cell division. Here, we describe a novel role of GIS, controlling trichome cell division indirectly by interacting genetically with a key endoreduplication regulator SIAMESE (SIM). Our molecular and genetic studies have shown that GIS might indireclty control cell division and trichome branching by acting downstream of SIM. A loss of function mutation of SIM signficantly reduced the expression of GIS. Futhermore, the overexpression of GIS rescued the trichome cluster cell phenotypes of sim mutant. The gain or loss of function of GIS had no significant effect on the expression of SIM. These results suggest that GIS may play an indirect role in regulating trichome cell division by genetically interacting with SIM. PMID:23825141

  3. GLABROUS1 overexpression and TRIPTYCHON alter the cell cycle and trichome cell fate in Arabidopsis.

    PubMed Central

    Szymanski, D B; Marks, M D

    1998-01-01

    Cellular competence, initiation cues, and inhibition signals control the distribution of trichomes on the Arabidopsis leaf. The GLABROUS1 (GL1) gene has a dual role in that it is required for trichome initiation, but GL1 overexpression reduces trichome number. We have found that a mutation in the TRIPTYCHON (TRY) gene partially suppresses the GL1 overexpression phenotype but not in a way that indicates that TRY directly controls an epidermal inhibition pathway. Surprisingly, cauliflower mosaic virus 35S::GL1 try plants contain a subclass of trichomes derived from the subepidermal layer. Altered cell cycle control was also detected in 35S::GL1 and try plants. A mutation in TRY led to increased epidermal and mesophyll cell number, a reduction in endoreduplication in the epidermis, and an increase in endoreduplication in trichomes. GL1 overexpression also reduced endoreduplication levels in both the epidermis and trichomes; however, in the presence of try, it synergistically enhanced trichome endoreduplication. Interactions with the COTYLEDON TRICHOME1 (COT1) gene indicate that GL1 and TRY control trichome development and may be involved in cell cycle control during leaf development. PMID:9836744

  4. Trichome cell growth in Arabidopsis thaliana can be derepressed by mutations in at least five genes.

    PubMed Central

    Perazza, D; Herzog, M; Hülskamp, M; Brown, S; Dorne, A M; Bonneville, J M

    1999-01-01

    Leaf trichomes in Arabidopsis are unicellular epidermal hairs with a branched morphology. They undergo successive endoreduplication rounds early during cell morphogenesis. Mutations affecting trichome nuclear DNA content, such as triptychon or glabra3, alter trichome branching. We isolated new mutants with supernumerary trichome branches, which fall into three unlinked complementation groups: KAKTUS and the novel loci, POLYCHOME and RASTAFARI. They map to chromosomes IV, II, and V, respectively. The trichomes of these mutants presented an increased DNA content, although to a variable extent. The spindly-5 mutant, which displays a constitutive gibberellin response, also produces overbranched trichomes containing more nuclear DNA. We analyzed genetic interactions using double mutants and propose that two independent pathways, defined by SPINDLY and TRIPTYCHON, act to limit trichome growth. KAKTUS and POLYCHOME might have redundant actions mediating gibberellin control via SPINDLY. The overall leaf polysomaty was not notably affected by these mutations, suggesting that they affect the control of DNA synthesis in a tissue- or cell type-specific manner. Wild-type tetraploids also produce overbranched trichomes; they displayed a shifted polysomaty in trichomes and in the whole leaf, suggesting a developmental program controlling DNA increases via the counting of endoreduplication rounds. PMID:10224275

  5. Trichome cell growth in Arabidopsis thaliana can be derepressed by mutations in at least five genes.

    PubMed

    Perazza, D; Herzog, M; Hülskamp, M; Brown, S; Dorne, A M; Bonneville, J M

    1999-05-01

    Leaf trichomes in Arabidopsis are unicellular epidermal hairs with a branched morphology. They undergo successive endoreduplication rounds early during cell morphogenesis. Mutations affecting trichome nuclear DNA content, such as triptychon or glabra3, alter trichome branching. We isolated new mutants with supernumerary trichome branches, which fall into three unlinked complementation groups: KAKTUS and the novel loci, POLYCHOME and RASTAFARI. They map to chromosomes IV, II, and V, respectively. The trichomes of these mutants presented an increased DNA content, although to a variable extent. The spindly-5 mutant, which displays a constitutive gibberellin response, also produces overbranched trichomes containing more nuclear DNA. We analyzed genetic interactions using double mutants and propose that two independent pathways, defined by SPINDLY and TRIPTYCHON, act to limit trichome growth. KAKTUS and POLYCHOME might have redundant actions mediating gibberellin control via SPINDLY. The overall leaf polysomaty was not notably affected by these mutations, suggesting that they affect the control of DNA synthesis in a tissue- or cell type-specific manner. Wild-type tetraploids also produce overbranched trichomes; they displayed a shifted polysomaty in trichomes and in the whole leaf, suggesting a developmental program controlling DNA increases via the counting of endoreduplication rounds. PMID:10224275

  6. Maize leaf trichomes represent an entry point of infection for Fusarium species.

    PubMed

    Nguyen, Thi Thanh Xuan; Dehne, Heinz-Wilhelm; Steiner, Ulrike

    2016-08-01

    Fifteen day old maize seedlings were inoculated with Fusarium graminearum, Fusarium proliferatum, and Fusarium verticillioides. More than 90 % F. proliferatum and F. verticillioides conidia and 50 % of F. graminearum formed one germ tube whereas the other 50 % of F. graminearum conidia formed two to three germ tubes. The germ tubes of F. graminearum conidia were longer than those of F. proliferatum and F. verticillioides. The three species of Fusarium infected bi-cellular trichomes by adhering and growing along the trichomes or by attaching to the cap cell of the trichomes 48 h after inoculation. Hyphae penetrated into the trichomes at the base, the side or at the top of the cap cells. The hyphae colonized the cap cells and then spread to base cells. Prickle trichomes were infected 72 h after inoculation. The hyphae either wrapped around prickle trichomes or formed a mass of hyphae around the top of prickle trichomes or formed appressorium. Macro trichomes were infected by F. graminearum 7 d after inoculation. Following penetration, the fungus spread to adjacent epidermal cells and to the subcuticle. This investigation provides the first assessment of F. graminearum, F. proliferatum, and F. verticillioides infection via trichomes of maize leaves. PMID:27521623

  7. Hip-Hop Education Resources

    ERIC Educational Resources Information Center

    Hall, Marcella Runell

    2009-01-01

    Hip-hop music and culture are often cited as being public pedagogy, meaning the music itself has intrinsic educational value. Non-profit organizations and individual educators have graciously taken the lead in utilizing hip-hop to educate. As the academy continues to debate its effectiveness, teachers and community organizers are moving forward.…

  8. An overview of the gene regulatory network controlling trichome development in the model plant, Arabidopsis

    PubMed Central

    Pattanaik, Sitakanta; Patra, Barunava; Singh, Sanjay Kumar; Yuan, Ling

    2014-01-01

    Trichomes are specialized epidermal cells located on aerial parts of plants and are associated with a wide array of biological processes. Trichomes protect plants from adverse conditions including UV light and herbivore attack and are also an important source of a number of phytochemicals. The simple unicellular trichomes of Arabidopsis serve as an excellent model to study molecular mechanism of cell differentiation and pattern formation in plants. The emerging picture suggests that the developmental process is controlled by a transcriptional network involving three major groups of transcription factors (TFs): the R2R3 MYB, basic helix-loop-helix (bHLH), and WD40 repeat (WDR) protein. These regulatory proteins form a trimeric activator complex that positively regulates trichome development. The single repeat R3 MYBs act as negative regulators of trichome development. They compete with the R2R3 MYBs to bind the bHLH factor and form a repressor complex. In addition to activator–repressor mechanism, a depletion mechanism may operate in parallel during trichome development. In this mechanism, the bHLH factor traps the WDR protein which results in depletion of WDR protein in neighboring cells. Consequently, the cells with high levels of bHLH and WDR proteins are developed into trichomes. A group of C2H2 zinc finger TFs has also been implicated in trichome development. Phytohormones, including gibberellins and jasmonic acid, play significant roles in this developmental process. Recently, microRNAs have been shown to be involved in trichome development. Furthermore, it has been demonstrated that the activities of the key regulatory proteins involved in trichome development are controlled by the 26S/ubiquitin proteasome system (UPS), highlighting the complexity of the regulatory network controlling this developmental process. To complement several excellent recent relevant reviews, this review focuses on the transcriptional network and hormonal interplay controlling

  9. Fast Neutron induced structural rearrangements at a soybean NAP1 locus result in gnarled trichomes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A soybean (Glycine max (L.) Merr.) gnarled trichome mutant, exhibiting stunted trichomes compared to wild-type, was identified in a fast neutron mutant population. Genetic mapping using whole genome sequence-based bulked segregant analysis identified a 26.6 megabase interval on chromosome 20 that ...

  10. Effects of leaf and bract trichomes on trash content and quality of ginned lint

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spinning efficiency and yarn quality is improved for bales with reduced trash content. Some cotton varieties have been characterized as having smoother leaves (low trichome density) and fewer bract trichomes, and it has been shown that cotton harvested from these varieties are picked with lower tra...

  11. Reliable and efficient hop-by-hop flow control

    NASA Astrophysics Data System (ADS)

    Ozveren, Cuneyt M.; Simcoe, Robert; Varghese, George

    1995-05-01

    Hop-by-hop flow control can be used to fairly share the bandwidth of a network among competing flows. No data is lost even in overload conditions; yet each flow gets access to the maximum throughput when the network is lightly loaded. However, some schemes for hop-by-hop flow control require too much memory; some of them are not resilient to errors. We propose a scheme for making hop-by-hop flow control resilient and show that it has advantages over the first several schemes proposed by Kung. We also describe a novel method for sharing the available buffers among the flows on a link; our scheme allows us to potentially reduce the memory requirement (or increase the number of flows that can be supported) by an order of magnitude. Most of the work is described in the context of an ATM network that uses credit-based flow control. However, our ideas extend to networks in which flows can be distinguished, and to rate-based flow control schemes.

  12. Molecular basis of natural variation and environmental control of trichome patterning.

    PubMed

    Hauser, Marie-Theres

    2014-01-01

    Trichomes are differentiated epidermal cells on above ground organs of nearly all land plants. They play important protective roles as structural defenses upon biotic attacks such as herbivory, oviposition and fungal infections, and against abiotic stressors such as drought, heat, freezing, excess of light, and UV radiation. The pattern and density of trichomes is highly variable within natural population suggesting tradeoffs between traits positively affecting fitness such as resistance and the costs of trichome production. The spatial distribution of trichomes is regulated through a combination of endogenous developmental programs and external signals. This review summarizes the current understanding on the molecular basis of the natural variation and the role of phytohormones and environmental stimuli on trichome patterning. PMID:25071803

  13. Star-Hopping

    NASA Astrophysics Data System (ADS)

    Garfinkle, Robert A.

    1997-07-01

    Introduction; Preface; Acknowledgements; 1. How to use this book and what you are going to see; 2. How the sky works, determining your field of view, observing tips and how to navigate in the night sky; 3. January - Taurus and Orion: the bull and hunter; 4. February - Canis Minor, Canis Major, and Puppis: dog days in February and Jason's Argo; 5. March - Cancer, Leo, and Corvus: a crab, the king of the beasts, and a crow; 6. April - Ursa Major: a dipper round tripper; 7. May - Coma Berenices and Virgo: the sparkling hair of Berenice and the wheat maiden and her bushel of galaxies; 8. June - Libra and Lupus: the balance scales and the wolf; 9. July - Scorpius, Sagittarius, and Scutum: the scorpion, archer, and shield of John Sobieski; 10. August - Draco: following the trail of the dragon; 11. September - Cygnus, Lyra, Vulpecula, and Sagitta: the swan, lyre, fox, and arrow; 12. October - Andromeda and Perseus: the chained lady and her rescuer; 13. November - Cepheus and Cassiopeia: the king and queen of Joppa; 14. December - Pisces, Triangulum, and Aries: of fishes, a triangle, and a ram; 15. Messier Marathon, a sundown to sunup hop across the skies; Appendix A: Classification tables; Appendix B: The constellations; Appendix C: The Greek alphabet; Appendix D: Decimalization of the day; Glossary; Bibliography; Index.

  14. Organized F-actin is essential for normal trichome morphogenesis in Arabidopsis.

    PubMed Central

    Szymanski, D B; Marks, M D; Wick, S M

    1999-01-01

    Actin microfilaments form a three-dimensional cytoskeletal network throughout the cell and constitute an essential throughway for organelle and vesicle transport. Development of Arabidopsis trichomes, unicellular structures derived from the epidermis, is being used as a genetic system in which to study actin-dependent growth in plant cells. The present study indicates that filamentous actin (F-actin) plays an important role during Arabidopsis trichome morphogenesis. For example, immunolocalization of actin filaments during trichome morphogenesis identified rearrangements of the cytoskeletal structure during the development of the mature cell. Moreover, pharmacological experiments indicate that there are distinct requirements for actin- and microtubule-dependent function during trichome morphogenesis. The F-actin-disrupting drug cytochalasin D does not affect the establishment of polarity during trichome development; however, maintenance and coordination of the normal pattern of cell growth are very sensitive to this drug. In contrast, oryzalin, an agent that depolymerizes microtubules, severely inhibits cell polarization. Furthermore, cytochalasin D treatment phenocopies a known class of mutations that cause distorted trichome morphology. Results of an analysis of cell shape and microfilament structure in wild-type, mutant, and drug-treated trichomes are consistent with a role for actin in the maintenance and coordination of an established growth pattern. PMID:10590162

  15. A regulatory gene induces trichome formation and embryo lethality in tomato

    PubMed Central

    Yang, Changxian; Zhang, Junhong; Luo, Zhidan; Gong, Pengjuan; Zhang, Chanjuan; Wang, Taotao; Zhang, Yuyang; Lu, Yong'en; Ye, Zhibiao

    2011-01-01

    Trichomes are universal biological structures originating from the aerial epidermis, which serve as an excellent model to study plant differentiation at the cell level. Although the pathway regulating trichome formation in the Rosids has been well characterized, only very recently a few genes were identified for trichome initiation in the Asterids. In this study, we cloned Woolly (Wo), essential for trichome formation in tomato. Transgenic experiments revealed that the woolly phenotype is caused by the mutation in Wo which encodes a homeodomain protein containing a bZIP motif and a START domain. We identified three alleles of Wo and found that each allele contains a missense mutation, which respectively results in an amino acid substitution at the C terminus. Microarray and expression analysis showed that the expression of a B-type cyclin gene, SlCycB2, is possibly regulated by Wo, which also participates in trichome formation. Suppression of Wo or SlCycB2 expression by RNAi decreased the number of type I trichomes, and direct protein–protein interaction was detected between them, implying that both proteins may work together in the regulation of this type of trichome formation. Cytological observation and Wo transcript analysis in the developing seeds showed that embryo development was also correlated with Wo. PMID:21730153

  16. Glandular Odontogenic Cyst of Mandible: A Rare Entity

    PubMed Central

    Mittal, Ankur; Kaur, Gursheen; Sood, Neena

    2015-01-01

    Glandular odontogenic cyst (GOC) is a rare developmental odontogenic cyst. It is a slow growing and asymptomatic swelling, usually affecting middle aged men and has tendency to reoccur. Here, we report a case of GOC in the anterior portion of mandible diagnosed by histopathology. PMID:26813085

  17. Glandular dose in breast computed tomography with synchrotron radiation.

    PubMed

    Mettivier, G; Fedon, C; Di Lillo, F; Longo, R; Sarno, A; Tromba, G; Russo, P

    2016-01-21

    The purpose of this work is to provide an evaluation of the mean glandular dose (MGD) for breast computed tomography (CT) with synchrotron radiation in an axial scanning configuration with a partial or total organ volume irradiation, for the in vivo program of breast CT ongoing at the ELETTRA facility (Trieste, Italy). A Geant4 Monte Carlo code was implemented, simulating the photon irradiation from a synchrotron radiation source in the energetic range from 8 to 50 keV with 1 keV intervals, to evaluate the MGD. The code was validated with literature data, in terms of mammographic normalized glandular dose coefficients (DgN) and with ad hoc experimental data, in terms of computed tomography dose index (CTDI). Simulated cylindrical phantoms of different sizes (diameter at phantom base 8, 10, 12, 14 or 16 cm, axial length 1.5 times the radius) and glandular fraction by weight (0%, 14.3%, 25%, 50%, 75% and 100%) were implemented into the code. The validation of the code shows an excellent agreement both with previously published work and in terms of DgN and CDTI measurements. The implemented simulations show a dependence of the glandular dose estimate on the vertical dimension of the irradiated zone when a partial organ irradiation was implemented. Specific normalized coefficients for calculating the MGD to the whole breast or to the single irradiated slice were reported. PMID:26683710

  18. Glandular dose in breast computed tomography with synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Mettivier, G.; Fedon, C.; Di Lillo, F.; Longo, R.; Sarno, A.; Tromba, G.; Russo, P.

    2016-01-01

    The purpose of this work is to provide an evaluation of the mean glandular dose (MGD) for breast computed tomography (CT) with synchrotron radiation in an axial scanning configuration with a partial or total organ volume irradiation, for the in vivo program of breast CT ongoing at the ELETTRA facility (Trieste, Italy). A Geant4 Monte Carlo code was implemented, simulating the photon irradiation from a synchrotron radiation source in the energetic range from 8 to 50 keV with 1 keV intervals, to evaluate the MGD. The code was validated with literature data, in terms of mammographic normalized glandular dose coefficients (DgN) and with ad hoc experimental data, in terms of computed tomography dose index (CTDI). Simulated cylindrical phantoms of different sizes (diameter at phantom base 8, 10, 12, 14 or 16 cm, axial length 1.5 times the radius) and glandular fraction by weight (0%, 14.3%, 25%, 50%, 75% and 100%) were implemented into the code. The validation of the code shows an excellent agreement both with previously published work and in terms of DgN and CDTI measurements. The implemented simulations show a dependence of the glandular dose estimate on the vertical dimension of the irradiated zone when a partial organ irradiation was implemented. Specific normalized coefficients for calculating the MGD to the whole breast or to the single irradiated slice were reported.

  19. [The glandular odontogenic cyst--a rare entity].

    PubMed

    Brauer, H U; Manegold-Brauer, G

    2014-05-01

    In this short communication, the very rare glandular odontogenic cyst (GOC) is presented as an independent entity. The GOC is a jawbone cyst of the maxilla and mandible. The typical radiological and histopathological characteristics of the GOC are described. Furthermore, differential diagnoses, current treatment options and the recurrence rates of this of entity are discussed. PMID:24633391

  20. Hop extracts and hop substances in treatment of menopausal complaints.

    PubMed

    Keiler, Annekathrin M; Zierau, Oliver; Kretzschmar, Georg

    2013-05-01

    Hop extract is a long used medicinal product and, regarding hormonal activities, in 1999 a number of prenylflavanones have been identified as its major constituents with 8-prenylnaringenin (8-PN) being the main active estrogenic compound. There have been several in vivo studies performed that demonstrate the potential of hop extract and the single compound 8-PN to alleviate climacteric symptoms like osteoporosis, vasomotoric complaints, and sexual motivation. On the other hand, only a few clinical studies have been performed so far, and these mainly focused on menopausal discomforts, especially hot flushes, yielding rather inconclusive results. Despite preferentially activating estrogen receptor α, 8-PN is only slightly uterotrophic, but it also elucidates estrogenic effects on the mammary gland. In conclusion, although hop extract and especially 8-PN are promising candidates as a relief for climacteric symptoms, data on the safety and efficacy is still scarce. PMID:23512496

  1. How is Cd Incorporated in Biominerals Eliminated by Tobacco Trichomes?

    NASA Astrophysics Data System (ADS)

    Hokura, Akiko

    In tobacco plants, elimination of Zn and Cd via the production of Ca-containing grains at the top of leaf hairs, called trichomes, is a potent detoxification mechanism. When tobacco plants were grown in a nutrient solution containing an amount of Cd and low Ca supplement, most of the grains were oblong-shaped and low-Cd-substituted calcite. When exposed to the same amount of Cd and high Ca supplement, grains were more abundant and diverse in compositions, and in total more Cd was eliminated. Most grains in the high Ca/Cd experiment were round-shaped and composed predominantly of Cd-substituted vaterite, a usually metastable calcium carbonate polymorph, and subordinate calcite.

  2. Foliar trichome-aided formaldehyde uptake in the epiphytic Tillandsia velutina and its response to formaldehyde pollution.

    PubMed

    Li, Peng; Pemberton, Robert; Zheng, Guiling

    2015-01-01

    Epiphytic Tillandsia (Bromeliaceae) species have been found to be efficient biomonitors of atmospheric heavy metals and persistent organic pollutants, but have not been used to monitor or remove the primary indoor atmospheric pollutant formaldehyde (FA). The absorptive capacity of Tillandsia trichomes is well-established, but potential secondary effects of foliar trichomes on gas exchange remain unclear. Our study investigated whether Tillandsia species can absorb FA efficiently and if the leaf trichomes function to improve FA uptake, using Tillandsia velutina. Plants with intact trichomes, decreased FA concentration by 48.42% in 12 h from 1060 μg m(-3) to 546.67 μg m(-3), while FA concentration decreased only by 22.51% in the plants without trichomes. Moreover, the more trichomes removed from the leaves, the lower the capability of FA uptake per unit leaf area, which suggested that T. velutina was capable of absorbing a large amount of FA via the leaves and specialized trichomes facilitated the whole leaf tissue FA absorption. In addition, all plants exposed to FA were chloric, had a reduction in measured leaf chlorophyll, and an increment in permeability of plasma membranes. However, plants in which trichomes had been removed declined or increased more quickly than plants with intact trichomes, indicating Tillandsia leaf trichomes also give the leaves some protection against this toxin. PMID:25150968

  3. Proteomic analysis of the medicinal plant Artemisia annua: Data from leaf and trichome extracts.

    PubMed

    Bryant, Laura; Patole, Chhaya; Cramer, Rainer

    2016-06-01

    This article contains raw and processed data related to research published by Bryant et al.[1]. Data was obtained by MS-based proteomics, analysing trichome-enriched, trichome-depleted and whole leaf samples taken from the medicinal plant Artemisia annua and searching the acquired MS/MS data against a recently published contig database [2] and other genomic and proteomic sequence databases for comparison. The processed data shows that an order-of-magnitude more proteins have been identified from trichome-enriched Artemisia annua samples in comparison to previously published data. Proteins known to have a role in the biosynthesis of artemisinin and other highly abundant proteins were found which imply additional enzymatically driven processes occurring within the trichomes that are significant for the biosynthesis of artemisinin. PMID:26977431

  4. Proteomic analysis of the medicinal plant Artemisia annua: Data from leaf and trichome extracts

    PubMed Central

    Bryant, Laura; Patole, Chhaya; Cramer, Rainer

    2016-01-01

    This article contains raw and processed data related to research published by Bryant et al.[1]. Data was obtained by MS-based proteomics, analysing trichome-enriched, trichome-depleted and whole leaf samples taken from the medicinal plant Artemisia annua and searching the acquired MS/MS data against a recently published contig database [2] and other genomic and proteomic sequence databases for comparison. The processed data shows that an order-of-magnitude more proteins have been identified from trichome-enriched Artemisia annua samples in comparison to previously published data. Proteins known to have a role in the biosynthesis of artemisinin and other highly abundant proteins were found which imply additional enzymatically driven processes occurring within the trichomes that are significant for the biosynthesis of artemisinin. PMID:26977431

  5. A novel texture descriptor for detection of glandular structures in colon histology images

    NASA Astrophysics Data System (ADS)

    Sirinukunwattana, Korsuk; Snead, David R.; Rajpoot, Nasir M.

    2015-03-01

    The first step prior to most analyses on most histopathology images is the detection of area of interest. In this work, we present a superpixel-based approach for glandular structure detection in colon histology images. An image is first segmented into superpixels with the constraint on the presence of glandular boundaries. Texture and color information is then extracted from each superpixel to calculate the probability of that superpixel belonging to glandular regions, resulting in a glandular probability map. In addition, we present a novel texture descriptor derived from a region covariance matrix of scattering coefficients. Our approach shows encouraging results for the detection of glandular structures in colon tissue samples.

  6. Hip-Hop and the Academic Canon

    ERIC Educational Resources Information Center

    Abe, Daudi

    2009-01-01

    Over the last 30 years, the hip-hop movement has risen from the margins to become the preeminent force in US popular culture. In more recent times academics have begun to harness the power of hip-hop culture and use it as a means of infusing transformative knowledge into the mainstream academic discourse. On many college campuses, hip-hop's…

  7. Mean glandular dose in a breast screening programme

    SciTech Connect

    Galvan, H. A.; Perez-Badillo, M. P.; Villasenor, Y.

    2012-10-23

    Breast density has an important role in early detection of breast cancer, because has been reported the strong association between breast density and invasive breast cancer risk. Mammography is the gold standard to early detection of breast cancer, despite of this require ionizing radiation that may increase radio-induced cancer risk. This maybe limited with a quality control programme of mammographic units, with the main goal of achieving high quality images with low radiation dose. International Atomic Energy Agency (IAEA) published in 2011 the {sup Q}uality assurance programme for digital mammography{sup ,} where glandular tissue quantity is an important parameter to compute mean glandular dose (MGD), which is necessary to reduce its associated risk. In this work we show the first results in our country applying this protocol and studying breast density in a small group. MGD complies with national and IAEA dose limits.

  8. Mean glandular dose in a breast screening programme

    NASA Astrophysics Data System (ADS)

    Galván, H. A.; Pérez-Badillo, M. P.; Villaseñor, Y.

    2012-10-01

    Breast density has an important role in early detection of breast cancer, because has been reported the strong association between breast density and invasive breast cancer risk. Mammography is the gold standard to early detection of breast cancer, despite of this require ionizing radiation that may increase radio-induced cancer risk. This maybe limited with a quality control programme of mammographic units, with the main goal of achieving high quality images with low radiation dose. International Atomic Energy Agency (IAEA) published in 2011 the "Quality assurance programme for digital mammography", where glandular tissue quantity is an important parameter to compute mean glandular dose (MGD), which is necessary to reduce its associated risk. In this work we show the first results in our country applying this protocol and studying breast density in a small group. MGD complies with national and IAEA dose limits.

  9. Hip-Hop Pop Art

    ERIC Educational Resources Information Center

    Talley, Clarence, Sr.

    2011-01-01

    Art has a way of helping students better understand and appreciate the world around them, particularly the things that are most important to them. Hip hop is one of those generational genres that capture the attention of young students like few other things do. Drawing on this genre to get students to create art is an excellent way to demonstrate…

  10. Long range hopping mobility platform.

    SciTech Connect

    Spletzer, Barry Louis; Fischer, Gary John

    2003-03-01

    Sandia National Laboratories has developed a mesoscale hopping mobility platform (Hopper) to overcome the longstanding problems of mobility and power in small scale unmanned vehicles. The system provides mobility in situations such as negotiating tall obstacles and rough terrain that are prohibitive for other small ground base vehicles. The Defense Advanced Research Projects Administration (DARPA) provided the funding for the hopper project.

  11. Semi-automated 3D Leaf Reconstruction and Analysis of Trichome Patterning from Light Microscopic Images

    PubMed Central

    Schrader, Andrea; Hülskamp, Martin; Tresch, Achim

    2013-01-01

    Trichomes are leaf hairs that are formed by single cells on the leaf surface. They are known to be involved in pathogen resistance. Their patterning is considered to emerge from a field of initially equivalent cells through the action of a gene regulatory network involving trichome fate promoting and inhibiting factors. For a quantitative analysis of single and double mutants or the phenotypic variation of patterns in different ecotypes, it is imperative to statistically evaluate the pattern reliably on a large number of leaves. Here we present a method that enables the analysis of trichome patterns at early developmental leaf stages and the automatic analysis of various spatial parameters. We focus on the most challenging young leaf stages that require the analysis in three dimensions, as the leaves are typically not flat. Our software TrichEratops reconstructs 3D surface models from 2D stacks of conventional light-microscope pictures. It allows the GUI-based annotation of different stages of trichome development, which can be analyzed with respect to their spatial distribution to capture trichome patterning events. We show that 3D modeling removes biases of simpler 2D models and that novel trichome patterning features increase the sensitivity for inter-accession comparisons. PMID:23637587

  12. Modeling Filamentous Cyanobacteria Reveals the Advantages of Long and Fast Trichomes for Optimizing Light Exposure

    PubMed Central

    Tamulonis, Carlos; Postma, Marten; Kaandorp, Jaap

    2011-01-01

    Cyanobacteria form a very large and diverse phylum of prokaryotes that perform oxygenic photosynthesis. Many species of cyanobacteria live colonially in long trichomes of hundreds to thousands of cells. Of the filamentous species, many are also motile, gliding along their long axis, and display photomovement, by which a trichome modulates its gliding according to the incident light. The latter has been found to play an important role in guiding the trichomes to optimal lighting conditions, which can either inhibit the cells if the incident light is too weak, or damage the cells if too strong. We have developed a computational model for gliding filamentous photophobic cyanobacteria that allows us to perform simulations on the scale of a Petri dish using over 105 individual trichomes. Using the model, we quantify the effectiveness of one commonly observed photomovement strategy—photophobic responses—in distributing large populations of trichomes optimally over a light field. The model predicts that the typical observed length and gliding speeds of filamentous cyanobacteria are optimal for the photophobic strategy. Therefore, our results suggest that not just photomovement but also the trichome shape itself improves the ability of the cyanobacteria to optimize their light exposure. PMID:21789215

  13. Detecting uterine glandular lesions: Role of cervical cytology

    PubMed Central

    Bansal, Baneet; Gupta, Parikshaa; Gupta, Nalini; Rajwanshi, Arvind; Suri, Vanita

    2016-01-01

    Background: The sensitivity of cervical cytology for detection of glandular lesions is reported to be low. We conducted this study to assess the diagnostic accuracy of cervical Papanicolaou (Pap) smears for uterine glandular lesions and to compare the diagnostic utility of conventional and liquid-based cytology (LBC) smears for glandular lesions. Materials and Methods: Archived histopathology records of all cases reported as endocervical and endometrial adenocarcinoma in the study period were identified and the available corresponding Pap smears (in preceding 1 year) were retrieved. In addition, the Pap smears reported as glandular cell abnormalities (GCA) during the same study period were retrieved. The overall prevalence of GCA, sensitivity, and specificity of Pap smears for the detection of GCA was calculated. The diagnostic accuracy of conventional and LBC smears for the diagnosis of GCA was also compared. Results: The prevalence of GCA in our study was 0.32%. The overall specificity of Pap smears for the diagnosis of GCA was 60.8%, this was not significantly different between conventional and LBC smears (P = 0.4). The overall sensitivity of Pap smears for the detection of GCA was 41.8%; LBC smears had significantly better sensitivity as compared to conventional smears for the detection of endometrial as compared to endocervical adenocarcinoma (P < 0.05). Conclusions: The prevalence of GCA in Pap smears is low. The specificity of Pap smears, for diagnosis of GCA, was found to be moderate. However, the overall sensitivity of Pap smears for the detection of GCA was low, though better for LBC as compared to conventional smears. PMID:27014363

  14. Calcium promotes cadmium elimination as vaterite grains by tobacco trichomes

    NASA Astrophysics Data System (ADS)

    Isaure, Marie-Pierre; Sarret, Géraldine; Harada, Emiko; Choi, Yong-Eui; Marcus, Matthew A.; Fakra, Sirine C.; Geoffroy, Nicolas; Pairis, Sébastien; Susini, Jean; Clemens, Stephan; Manceau, Alain

    2010-10-01

    In tobacco plants, elimination of Zn and Cd via the production of Ca-containing grains at the top of leaf hairs, called trichomes, is a potent detoxification mechanism. This study examines how Cd is incorporated in these biominerals, and how calcium growth supplement modifies their nature. Scanning electron microscopy coupled with energy dispersive X-ray microanalysis (SEM-EDX), microfocused X-ray diffraction (μ-XRD), and microfocused X-ray absorption near edge structure (μ-XANES) spectroscopy were used to image the morphology of the grains, identify the crystallized mineral phases, and speciate Cd, respectively. The mineralogy of the grains and chemical form of Cd varied with the amount of Ca. When tobacco plants were grown in a nutrient solution containing 25 μM Cd and low Ca supplement (Ca/Cd = 11 mol ratio), most of the grains were oblong-shaped and low-Cd-substituted calcite. When exposed to the same amount of Cd and high Ca supplement (Ca/Cd = 131 mol ratio), grains were more abundant and diverse in compositions, and in total more Cd was eliminated. Most grains in the high Ca/Cd experiment were round-shaped and composed predominantly of Cd-substituted vaterite, a usually metastable calcium carbonate polymorph, and subordinate calcite. Calcium oxalate and a Ca amorphous phase were detected occasionally in the two treatments, but were devoid of Cd. The biomineralization of cadmium and implications of results for Cd exposure of smokers and phytoremediation are discussed.

  15. Metabolic engineering of terpene biosynthesis in plants using a trichome-specific transcription factor MsYABBY5 from spearmint (Mentha spicata).

    PubMed

    Wang, Qian; Reddy, Vaishnavi Amarr; Panicker, Deepa; Mao, Hui-Zhu; Kumar, Nadimuthu; Rajan, Chakravarthy; Venkatesh, Prasanna Nori; Chua, Nam-Hai; Sarojam, Rajani

    2016-07-01

    In many aromatic plants including spearmint (Mentha spicata), the sites of secondary metabolite production are tiny specialized structures called peltate glandular trichomes (PGT). Having high commercial values, these secondary metabolites are exploited largely as flavours, fragrances and pharmaceuticals. But, knowledge about transcription factors (TFs) that regulate secondary metabolism in PGT remains elusive. Understanding the role of TFs in secondary metabolism pathway will aid in metabolic engineering for increased yield of secondary metabolites and also the development of new production techniques for valuable metabolites. Here, we isolated and functionally characterized a novel MsYABBY5 gene that is preferentially expressed in PGT of spearmint. We generated transgenic plants in which MsYABBY5 was either overexpressed or silenced using RNA interference (RNAi). Analysis of the transgenic lines showed that the reduced expression of MsYABBY5 led to increased levels of terpenes and that overexpression decreased terpene levels. Additionally, ectopic expression of MsYABBY5 in Ocimum basilicum and Nicotiana sylvestris decreased secondary metabolite production in them, suggesting that the encoded transcription factor is probably a repressor of secondary metabolism. PMID:26842602

  16. Comparative structural profiling of trichome specialized metabolites in tomato (Solanum lycopersicum) and S. habrochaites: acylsugar profiles revealed by UHPLC/MS and NMR.

    PubMed

    Ghosh, Banibrata; Westbrook, Thomas C; Jones, A Daniel

    2014-01-01

    Many plants accumulate large quantities of specialized metabolites in secretory glandular trichomes (SGTs), which are specialized epidermal cells. In the genus Solanum, SGTs store a diverse collection of glucose and sucrose esters. Profiling of extracts from two accessions (LA1777 and LA1392) of Solanum habrochaites using ultra-high performance liquid chromatography-mass spectrometry (UHPLC/MS) revealed wide acylsugar diversity, with up to 11 isomers annotated for each individual elemental formula. These isomers arise from differences in ester chain lengths and their positions of substitution or branching. Since fragment ion masses were not sufficient to distinguish all isomers, 24 acylsucroses were purified from S. habrochaites accessions and cultivated tomato (Solanum lycopersicum M82) and characterized using NMR spectroscopy. Two-dimensional NMR spectra yielded assignments of positions of substitution of specific acyl groups, and locations of branching. The range of substitution was wider than reported earlier, and in contrast to previous reports, tetra- and penta-acylsucroses were substituted at position 2 with acyl groups other than acetate. Because UHPLC/MS fails to yield sufficient information about structure diversity, and quantitative NMR of acylsugar mixtures is confounded by structural redundancy, the strategic combination of NMR and UHPLC/MS provides a powerful approach for profiling a class of metabolites with great structural diversity across genotypes. PMID:24772058

  17. Hall effect in hopping regime

    NASA Astrophysics Data System (ADS)

    Avdonin, A.; Skupiński, P.; Grasza, K.

    2016-02-01

    A simple description of the Hall effect in the hopping regime of conductivity in semiconductors is presented. Expressions for the Hall coefficient and Hall mobility are derived by considering averaged equilibrium electron transport in a single triangle of localization sites in a magnetic field. Dependence of the Hall coefficient is analyzed in a wide range of temperature and magnetic field values. Our theoretical result is applied to our experimental data on temperature dependence of Hall effect and Hall mobility in ZnO.

  18. Intercellular transfer along the trichomes of the invasive terminal heterocyst forming cyanobacterium Cylindrospermopsis raciborskii CS-505.

    PubMed

    Plominsky, Álvaro M; Delherbe, Nathalie; Mandakovic, Dinka; Riquelme, Brenda; González, Karen; Bergman, Birgitta; Mariscal, Vicente; Vásquez, Mónica

    2015-03-01

    Cylindrospermopsis raciborskii CS-505 is an invasive freshwater filamentous cyanobacterium that when grown diazotrophically may develop trichomes of up to 100 vegetative cells while differentiating only two end heterocysts, the sole sites for their N2-fixation process. We examined the diazotrophic growth and intercellular transfer mechanisms in C. raciborskii CS-505. Subjecting cultures to a combined-nitrogen-free medium to elicit N2 fixation, the trichome length remained unaffected while growth rates decreased. The structures and proteins for intercellular communication showed that while a continuous periplasmic space was apparent along the trichomes, the putative septal junction sepJ gene is divided into two open reading frames and lacks several transmembrane domains unlike the situation in Anabaena, differentiating a 5-fold higher frequency of heterocysts. FRAP analyses also showed that the dyes calcein and 5-CFDA were taken up by heterocysts and vegetative cells, and that the transfer from heterocysts and 'terminal' vegetative cells showed considerably higher transfer rates than that from vegetative cells located in the middle of the trichomes. The data suggest that C. raciborskii CS-505 compensates its low-frequency heterocyst phenotype by a highly efficient transfer of the fixed nitrogen towards cells in distal parts of the trichomes (growing rapidly) while cells in central parts suffers (slow growth). PMID:25757729

  19. Entrapment of bed bugs by leaf trichomes inspires microfabrication of biomimetic surfaces

    PubMed Central

    Szyndler, Megan W.; Haynes, Kenneth F.; Potter, Michael F.; Corn, Robert M.; Loudon, Catherine

    2013-01-01

    Resurgence in bed bug infestations and widespread pesticide resistance have greatly renewed interest in the development of more sustainable, environmentally friendly methods to manage bed bugs. Historically, in Eastern Europe, bed bugs were entrapped by leaves from bean plants, which were then destroyed; this purely physical entrapment was related to microscopic hooked hairs (trichomes) on the leaf surfaces. Using scanning electron microscopy and videography, we documented the capture mechanism: the physical impaling of bed bug feet (tarsi) by these trichomes. This is distinct from a Velcro-like mechanism of non-piercing entanglement, which only momentarily holds the bug without sustained capture. Struggling, trapped bed bugs are impaled by trichomes on several legs and are unable to free themselves. Only specific, mechanically vulnerable locations on the bug tarsi are pierced by the trichomes, which are located at effective heights and orientations for bed bug entrapment despite a lack of any evolutionary association. Using bean leaves as templates, we microfabricated surfaces indistinguishable in geometry from the real leaves, including the trichomes, using polymers with material properties similar to plant cell walls. These synthetic surfaces snag the bed bugs temporarily but do not hinder their locomotion as effectively as real leaves. PMID:23576783

  20. New method for generating breast models featuring glandular tissue spatial distribution

    NASA Astrophysics Data System (ADS)

    Paixão, L.; Oliveira, B. B.; Oliveira, M. A.; Teixeira, M. H. A.; Fonseca, T. C. F.; Nogueira, M. S.

    2016-02-01

    Mammography is the main radiographic technique used for breast imaging. A major concern with mammographic imaging is the risk of radiation-induced breast cancer due to the high sensitivity of breast tissue. The mean glandular dose (DG) is the dosimetric quantity widely accepted to characterize the risk of radiation induced cancer. Previous studies have concluded that DG depends not only on the breast glandular content but also on the spatial distribution of glandular tissue within the breast. In this work, a new method for generating computational breast models featuring skin composition and glandular tissue distribution from patients undergoing digital mammography is proposed. Such models allow a more accurate way of calculating individualized breast glandular doses taking into consideration the glandular tissue fraction. Sixteen breast models of four patients with different glandularity breasts were simulated and the results were compared with those obtained from recommended DG conversion factors. The results show that the internationally recommended conversion factors may be overestimating the mean glandular dose to less dense breasts and underestimating the mean glandular dose for denser breasts. The methodology described in this work constitutes a powerful tool for breast dosimetry, especially for risk studies.

  1. The biomechanics of vertical hopping: a review.

    PubMed

    Lamontagne, Mario; Kennedy, Matthew J

    2013-01-01

    Repetitive vertical hopping is a simple and relatively controlled task useful for studying basic neuromuscular properties and tissue mechanics. However, several biomechanical and physiological factors are involved. This article provides an overview of muscle and tendon properties and how these interact during vertical hopping. Muscle properties discussed are force-velocity and force-length relationships, electromechanical delay, muscle fiber type, stretch induced contraction amplification, and muscle spindle afferent feedback. Tendon properties include storage and reuse of elastic energy, tendon stiffness, afferent information from Golgi tendon organs, and failure points. These muscle and tendon properties interact to generate vertical hopping force and power. In addition to these basic properties, there are other more complicated factors to consider when analyzing vertical hopping such as balance and coordination. A wealth of information can be gathered by studying vertical hopping. Caution should be taken, however, to prevent inappropriate conclusions being drawn about hop performance due to oversimplification. PMID:24067123

  2. Population Responses of Potato Leafhopper (Hemiptera: Cicadellidae) to Insecticide in Glandular-Haired and Non-glandular-Haired Alfalfa Cultivars.

    PubMed

    Sulc, R Mark; McCormick, John S; Hammond, Ronald B; Miller, David J

    2014-12-01

    Conflicting results have been reported on the ability of glandular-haired alfalfa (Medicago sativa L.) cultivars to reduce potato leafhopper, Empoasca fabae Harris, population abundance in field environments. We measured potato leafhopper adult and nymph abundance and yield responses in a cultivar selected for high potato leafhopper resistance ('54H91') and in a non-glandular-haired susceptible cultivar ('54V54') with and without insecticide treatment across 3 yr. Treatments included no insecticide and insecticide applied either early or late in each summer growth cycle. Date × cultivar × treatment interactions were found for potato leafhopper population abundance. In the absence of insecticides, total potato leafhopper abundance (adults + nymphs per sweep) was lower in 54H91 than in 54V54 on 85% of sampling dates; cultivar differences were especially evident as potato leafhopper abundance peaked. Insecticide treatment reduced potato leafhopper populations in both cultivars, but populations recovered and often exceeded the normal action threshold in both cultivars within 2-3 wk of insecticide application. Yield gain from early insecticide treatment of 54V54 was >400 kg/ha in 11 of 14 summer harvests, whereas in 54H91 the yield gain was <250 kg/ha in 10 of 14 summer harvests. We conclude that glandular-haired alfalfa cultivars with high levels of potato leafhopper resistance significantly suppress potato leafhopper adult and nymph abundance, reduce yield losses in the absence of insecticides, and have potential within an integrated pest management strategy to reduce insecticide use in alfalfa production systems. PMID:26470072

  3. Cover Story: The Miseducation of Hip-Hop.

    ERIC Educational Resources Information Center

    Evelyn, Jamilah

    2000-01-01

    Some higher education officials believe that hip-hop music is eating away at the morals, and ultimately the classroom experience, of today's college students. Discusses why the gap exists between student and faculty attitudes toward hip-hop, how hip-hop music represents blackness, how people perceive hip-hop youth, the positive side of hip-hop,…

  4. Cell wall maturation of Arabidopsis trichomes is dependent on exocyst subunit EXO70H4 and involves callose deposition.

    PubMed

    Kulich, Ivan; Vojtíková, Zdeňka; Glanc, Matouš; Ortmannová, Jitka; Rasmann, Sergio; Žárský, Viktor

    2015-05-01

    Arabidopsis (Arabidopsis thaliana) leaf trichomes are single-cell structures with a well-studied development, but little is understood about their function. Developmental studies focused mainly on the early shaping stages, and little attention has been paid to the maturation stage. We focused on the EXO70H4 exocyst subunit, one of the most up-regulated genes in the mature trichome. We uncovered EXO70H4-dependent development of the secondary cell wall layer, highly autofluorescent and callose rich, deposited only in the upper part of the trichome. The boundary is formed between the apical and the basal parts of mature trichome by a callose ring that is also deposited in an EXO70H4-dependent manner. We call this structure the Ortmannian ring (OR). Both the secondary cell wall layer and the OR are absent in the exo70H4 mutants. Ecophysiological aspects of the trichome cell wall thickening include interference with antiherbivore defense and heavy metal accumulation. Ultraviolet B light induces EXO70H4 transcription in a CONSTITUTIVE PHOTOMORPHOGENIC1-dependent way, resulting in stimulation of trichome cell wall thickening and the OR biogenesis. EXO70H4-dependent trichome cell wall hardening is a unique phenomenon, which may be conserved among a variety of the land plants. Our analyses support a concept that Arabidopsis trichome is an excellent model to study molecular mechanisms of secondary cell wall deposition. PMID:25767057

  5. Adhesion and splash dispersal of Salmonella enterica Typhimurium on tomato leaflets: effects of rdar morphotype and trichome density.

    PubMed

    Cevallos-Cevallos, Juan M; Gu, Ganyu; Danyluk, Michelle D; van Bruggen, Ariena H C

    2012-11-01

    Salmonella enterica strains with rdar (red dry and rough) and saw (smooth and white) morphotypes have previously been associated with tomato outbreaks but the dispersal mechanisms of these morphotypes are still poorly understood. In this study, Salmonella adhesion was distinguished from attachment by comparing different contact periods. Initial adhesion of rdar and saw morphotypes of Salmonella was compared in relation to tomato plants with different leaf trichome densities. Trichome densities were increased or reduced by treatment with jasmonic or salicylic acid, respectively. The overall effect of Salmonella morphotype and trichome density on splash dispersal was assessed in a rain simulator and correlated to cell hydrophobicity and initial adhesion. The presence of the rdar morphotype increased initial adhesion at high trichome densities but not at low trichome densities. Attachment of the rdar strain occurred after 30s contact time regardless of trichome density. Splash dispersal was slightly further for the saw morphotype than the rdar morphotype of S. enterica at all trichome densities. Salmonella cells of both morphotypes survived significantly better on the surface of high trichome density leaflets. PMID:23141646

  6. Complete Genome Sequence of a Hop Latent Virus Infecting Hop Plants

    PubMed Central

    Jo, Yeonhwa; Choi, Hoseong

    2015-01-01

    The hop latent virus is a single-stranded RNA virus that mainly infects hop plants. Here, we report the complete genome sequence of a hop latent virus, which was de novo assembled by RNA sequencing (RNA-seq). Our study indicates that transcriptome data are useful for identifying a complete viral genome. PMID:25908127

  7. Hops

    MedlinePlus

    ... health provider.Medications changed by the liver (Cytochrome P450 1A1 (CYP1A1) substrates)Some medications are changed and ... health provider.Medications changed by the liver (Cytochrome P450 1A2 (CYP1A2) substrates)Some medications are changed and ...

  8. Hops

    MedlinePlus

    ... changed by the liver (Cytochrome P450 1A1 (CYP1A1) substrates)Some medications are changed and broken down by ... changed by the liver (Cytochrome P450 1A2 (CYP1A2) substrates)Some medications are changed and broken down by ...

  9. How Does a Hopping Kangaroo Breathe?

    ERIC Educational Resources Information Center

    Giuliodori, Mauricio J.; Lujan, Heidi L.; Janbaih, Hussein; DiCarlo, Stephen E.

    2010-01-01

    We developed a model to demonstrate how a hopping kangaroo breathes. Interestingly, a kangaroo uses less energy to breathe while hopping than while standing still. This occurs, in part, because rather than using muscle power to move air into and out of the lungs, air is pulled into (inspiration) and pushed out of (expiration) the lungs as the…

  10. Compendium of Hop Diseases and Pests

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This compendium of diseases, pests and other disorders of hop (Humulus lupulus L.) is designed to be a practical reference for anyone interested in growing hops, whether for commercial production, ornamental or home use. Growers, crop advisors, private consultants, home brewers, students, extension...

  11. Small polaron hopping transport along DNA molecules

    NASA Astrophysics Data System (ADS)

    Triberis, G. P.; Simserides, C.; Karavolas, V. C.

    2005-05-01

    We present a small polaron hopping model for interpreting the strong temperature (T) dependence of the electrical conductivity, σ, observed at high (h) temperatures along DNA molecules. The model takes into account the one-dimensional character of the system and the presence of disorder in the DNA double helix. Percolation-theoretical considerations lead to analytical expressions for the high temperature multiphonon-assisted small polaron hopping conductivity, the hopping distance and their temperature dependence. The experimental data for lambda phage DNA (λ-DNA) and poly(dA)-poly(dT) DNA follow nicely the theoretically predicted behaviour (lnσh~T-2/3). Moreover, our model leads to realistic values of the maximum hopping distances, supporting the idea of multiphonon-assisted hopping of small polarons between next nearest neighbours of the DNA molecular 'wire'. The low temperature case is also investigated.

  12. On transition rates in surface hopping

    NASA Astrophysics Data System (ADS)

    Escartín, J. M.; Romaniello, P.; Stella, L.; Reinhard, P.-G.; Suraud, E.

    2012-12-01

    Trajectory surface hopping (TSH) is one of the most widely used quantum-classical algorithms for nonadiabatic molecular dynamics. Despite its empirical effectiveness and popularity, a rigorous derivation of TSH as the classical limit of a combined quantum electron-nuclear dynamics is still missing. In this work, we aim to elucidate the theoretical basis for the widely used hopping rules. Naturally, we concentrate thereby on the formal aspects of the TSH. Using a Gaussian wave packet limit, we derive the transition rates governing the hopping process at a simple avoided level crossing. In this derivation, which gives insight into the physics underlying the hopping process, some essential features of the standard TSH algorithm are retrieved, namely (i) non-zero electronic transition rate ("hopping probability") at avoided crossings; (ii) rescaling of the nuclear velocities to conserve total energy; (iii) electronic transition rates linear in the nonadiabatic coupling vectors. The well-known Landau-Zener model is then used for illustration.

  13. Estimation of mean glandular dose for mammography of augmented breasts

    NASA Astrophysics Data System (ADS)

    Beckett, J. R.; Kotre, C. J.

    2000-11-01

    The standard quantity used to relate breast surface exposure to radiation risk is the mean dose received by the radiation sensitive tissue contained within the female breast, the mean glandular dose (MGD). At present, little is known about the MGD received by women with breast implants as there is no technique available to facilitate its calculation. The present work has involved modification of the conventional method for MGD estimation to make it applicable to women with augmented breasts. The technique was used to calculate MGDs for a cohort of 80 women with breast implants, which were compared with similar data calculated for a total of 1258 non-augmented women. Little difference was found in median MGD at low compressed breast thickness. At high breast thickness, however, the MGDs received by women with augmented breasts were found to be considerably lower than those relating to their non-augmented counterparts.

  14. Recurrent Glandular Odontogenic Cyst of Maxilla- A Case Report

    PubMed Central

    Jafarian, Amir Hosein; Rahpeyma, Amin; Khajehahmadi, Saeedeh

    2015-01-01

    The glandular odontogenic cyst (GOC) is a rare lesion with odontogenic origin. It shows a propensity for recurrence revealed in 30% of all case. This investigation reports a case of recurrent GOC in a 35-year-old female in the anterior region of the maxilla, which is uncommon and discusses about IHC finding, surgical methods, and differential diagnosis. Under general anesthesia, peripheral bone ostectomy via large round bur for removal of remaining epithelium of the cyst wall was done. Finally liquid nitrogen was used to remaining bone. This article recommends that soft tissue adjacent to the cortical bone perforation should be excised, as well as peripheral bone ostectomy by large round bur for removal of remaining epithelium of the cyst and liquid nitrogen application to the bony cavity. Because of high recurrence rate of the lesion close follow up of the patients is needed. PMID:26351478

  15. Lima bean – lady beetle interactions: hooked trichomes affect survival of Stethorus punctillum larvae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We tested the hypothesis that Lima bean Phaseolus lunatus L. (Henderson cultivar) trichome density affects the survival of the acariphagous lady beetle Stethorus punctillum Weise. When isolated throughout larval development, 10% or less of S. punctillum larvae reared on two-spotted spider mite Tetr...

  16. Expression of β-glucosidase increases trichome density and artemisinin content in transgenic Artemisia annua plants.

    PubMed

    Singh, Nameirakpam Dolendro; Kumar, Shashi; Daniell, Henry

    2016-03-01

    Artemisinin is highly effective against multidrug-resistant strains of Plasmodium falciparum, the aetiological agent of the most severe form of malaria. However, a low level of accumulation of artemisinin in Artemisia annua is a major limitation for its production and delivery to malaria endemic areas of the world. While several strategies to enhance artemisinin have been extensively explored, enhancing storage capacity in trichome has not yet been considered. Therefore, trichome density was increased with the expression of β-glucosidase (bgl1) gene in A. annua through Agrobacterium-mediated transformation. Transgene (bgl1) integration and transcript were confirmed by molecular analysis. Trichome density increased up to 20% in leaves and 66% in flowers of BGL1 transgenic plants than Artemisia control plants. High-performance liquid chromatography, time of flight mass spectrometer data showed that artemisinin content increased up to 1.4% in leaf and 2.56% in flowers (per g DW), similar to the highest yields achieved so far through metabolic engineering. Artemisinin was enhanced up to five-fold in BGL1 transgenic flowers. This study opens the possibility of increasing artemisinin content by manipulating trichomes' density, which is a major reservoir of artemisinin. Combining biosynthetic pathway engineering with enhancing trichome density may further increase artemisinin yield in A. annua. Because oral feeding of Artemisia plant cells reduced parasitemia more efficiently than the purified drug, reduced drug resistance and cost of prohibitively expensive purification process, enhanced expression should play a key role in making this valuable drug affordable to treat malaria in a large global population that disproportionally impacts low-socioeconomic areas and underprivileged children. PMID:26360801

  17. Steerable Hopping Six-Legged Robot

    NASA Technical Reports Server (NTRS)

    Younse, Paulo; Aghazarian, Hrand

    2010-01-01

    The figure depicts selected aspects of a six-legged robot that moves by hopping and that can be steered in the sense that it can be launched into a hop in a controllable direction. This is a prototype of hopping robots being developed for use in scientific exploration of rough terrain on remote planets that have surface gravitation less than that of Earth. Hopping robots could also be used on Earth, albeit at diminished hopping distances associated with the greater Earth gravitation. The upper end of each leg is connected through two universal joints to an upper and a lower hexagonal frame, such that the tilt of the leg depends on the relative position of the two frames. Two non-back-driveable worm-gear motor drives are used to control the relative position of the two frames along two axes 120 apart, thereby controlling the common tilt of all six legs and thereby, further, controlling the direction of hopping. Each leg includes an upper and a lower aluminum frame segment with a joint between them. A fiberglass spring, connected via hinges to both segments, is used to store hopping energy prior to launch into a hop and to cushion the landing at the end of the hop. A cable for loading the spring is run into each leg through the center of the universal joints and then down along the center lines of the segments to the lower end of the leg. A central spool actuated by a motor with a harmonic drive and an electromagnetic clutch winds in all six cables to compress all six springs (thereby also flexing all six legs) simultaneously. To ensure that all the legs push off and land in the same direction, timing- belt pulley drives are attached to the leg segments, restricting the flexing and extension of all six legs to a common linear motion. In preparation for a hop, the spool can be driven to load the spring legs by an amount corresponding to a desired hop distance within range. The amount of compression can be computed from the reading of a shaft-angle encoder that

  18. Breast dose in mammography is about 30% lower when realistic heterogeneous glandular distributions are considered

    SciTech Connect

    Hernandez, Andrew M.; Seibert, J. Anthony; Boone, John M.

    2015-11-15

    Purpose: Current dosimetry methods in mammography assume that the breast is comprised of a homogeneous mixture of glandular and adipose tissues. Three-dimensional (3D) dedicated breast CT (bCT) data sets were used previously to assess the complex anatomical structure within the breast, characterizing the statistical distribution of glandular tissue in the breast. The purpose of this work was to investigate the effect of bCT-derived heterogeneous glandular distributions on dosimetry in mammography. Methods: bCT-derived breast diameters, volumes, and 3D fibroglandular distributions were used to design realistic compressed breast models comprised of heterogeneous distributions of glandular tissue. The bCT-derived glandular distributions were fit to biGaussian functions and used as probability density maps to assign the density distributions within compressed breast models. The MCNPX 2.6.0 Monte Carlo code was used to estimate monoenergetic normalized mean glandular dose “DgN(E)” values in mammography geometry. The DgN(E) values were then weighted by typical mammography x-ray spectra to determine polyenergetic DgN (pDgN) coefficients for heterogeneous (pDgN{sub hetero}) and homogeneous (pDgN{sub homo}) cases. The dependence of estimated pDgN values on phantom size, volumetric glandular fraction (VGF), x-ray technique factors, and location of the heterogeneous glandular distributions was investigated. Results: The pDgN{sub hetero} coefficients were on average 35.3% (SD, 4.1) and 24.2% (SD, 3.0) lower than the pDgN{sub homo} coefficients for the Mo–Mo and W–Rh x-ray spectra, respectively, across all phantom sizes and VGFs when the glandular distributions were centered within the breast phantom in the coronal plane. At constant breast size, increasing VGF from 7.3% to 19.1% lead to a reduction in pDgN{sub hetero} relative to pDgN{sub homo} of 23.6%–27.4% for a W–Rh spectrum. Displacement of the glandular distribution, at a distance equal to 10% of the

  19. Effect of plant trichomes on the vertical migration of Haemonchus contortus infective larvae on five tropical forages.

    PubMed

    Oliveira, Aruaque L F; Costa, Ciniro; Rodella, Roberto A; Silva, Bruna F; Amarante, Alessandro F T

    2009-06-01

    The influence of trichomes on vertical migration and survival of Haemonchus contortus infective larvae (L3) on different forages was investigated. Four different forages showing different distributions of trichomes (Brachiaria brizantha cv. Marandu, Brachiaria brizantha cv. Xaraes, Andropogon gayanus, and Stylosanthes spp.), and one forage species without trichomes (Panicum maximum cv. Tanzania), were used. Forages cut at the post-grazing height were contaminated with faeces containing L3. Samples of different grass strata (0-10, 10-20, >20 cm) and faeces were collected for L3 quantification once per week over four weeks. In all forages studied, the highest L3 recovery occurred seven days after contamination, with the lowest recovery on A. gayanus. In general, larvae were found on all forages' strata. However, most of the larvae were at the lower stratum. There was no influence of trichomes on migration and survival of H. contortus L3 on the forages. PMID:18975119

  20. Biosynthesis of a new tobacco alkaloid, hydroxy-N-acylnornicotine in the trichomes of Nicotiana stocktonii. [Manduca sexta

    SciTech Connect

    Zador, E.; Jones, D.

    1986-04-01

    A new tobacco alkaloid from section Repandae is highly toxic to an insect (Manduca sexta) unsusceptible to previously described nicotine alkaloids (1). They have localized the alkaloid, HO-N-acylnornicotine (HO-NAN) nearly entirely to the exudate secreted by the epidermal trichomes of N. stocktonii. Only the nicotine and nornicotine were found in abundance inside the trichomes, while primarily nicotine was present inside the aerial vegetative parts and root. These results suggest that the HO-NAN is synthesized by the trichomes. When unlabelled nicotine was fed to isolated leaves there was an increase in internal nicotine, nornicotine and secretion of HO-NAN. Feeding leaves with 2'-C/sup 14/ nicotine resulted in labelling of both nornicotine and HO-NAN. These data strongly suggest synthesis of HO-NAN from nicotine via nornicotine in the trichomes, followed by rapid secretion. The possible evolutionary significance of this pathway of synthesis and secretion is discussed.

  1. Degradation of hop bitter acids by fungi

    SciTech Connect

    Huszcza, Ewa Bartmanska, Agnieszka; Aniol, Miroslaw; Maczka, Wanda; Zolnierczyk, Anna; Wawrzenczyk, Czeslaw

    2008-07-01

    Nine fungal strains related to: Trametes versicolor, Nigrospora oryzae, Inonotus radiatus, Crumenulopsis sororia, Coryneum betulinum, Cryptosporiopsis radicicola, Fusarium equiseti, Rhodotorula glutinis and Candida parapsilosis were tested for their ability to degrade humulones and lupulones. The best results were obtained for T. versicolor culture, in which humulones and lupulones were fully degraded after 4 days of incubation in the dark or after 36 h in the light. The experiments were performed on a commercial hop extract and on sterilized spent hops.

  2. Dosimetry in Mammography: Average Glandular Dose Based on Homogeneous Phantom

    NASA Astrophysics Data System (ADS)

    Benevides, Luis A.; Hintenlang, David E.

    2011-05-01

    The objective of this study was to demonstrate that a clinical dosimetry protocol that utilizes a dosimetric breast phantom series based on population anthropometric measurements can reliably predict the average glandular dose (AGD) imparted to the patient during a routine screening mammogram. AGD was calculated using entrance skin exposure and dose conversion factors based on fibroglandular content, compressed breast thickness, mammography unit parameters and modifying parameters for homogeneous phantom (phantom factor), compressed breast lateral dimensions (volume factor) and anatomical features (anatomical factor). The patient fibroglandular content was evaluated using a calibrated modified breast tissue equivalent homogeneous phantom series (BRTES-MOD) designed from anthropomorphic measurements of a screening mammography population and whose elemental composition was referenced to International Commission on Radiation Units and Measurements Report 44 and 46 tissues. The patient fibroglandular content, compressed breast thickness along with unit parameters and spectrum half-value layer were used to derive the currently used dose conversion factor (DgN). The study showed that the use of a homogeneous phantom, patient compressed breast lateral dimensions and patient anatomical features can affect AGD by as much as 12%, 3% and 1%, respectively. The protocol was found to be superior to existing methodologies. The clinical dosimetry protocol developed in this study can reliably predict the AGD imparted to an individual patient during a routine screening mammogram.

  3. Dosimetry in Mammography: Average Glandular Dose Based on Homogeneous Phantom

    SciTech Connect

    Benevides, Luis A.; Hintenlang, David E.

    2011-05-05

    The objective of this study was to demonstrate that a clinical dosimetry protocol that utilizes a dosimetric breast phantom series based on population anthropometric measurements can reliably predict the average glandular dose (AGD) imparted to the patient during a routine screening mammogram. AGD was calculated using entrance skin exposure and dose conversion factors based on fibroglandular content, compressed breast thickness, mammography unit parameters and modifying parameters for homogeneous phantom (phantom factor), compressed breast lateral dimensions (volume factor) and anatomical features (anatomical factor). The patient fibroglandular content was evaluated using a calibrated modified breast tissue equivalent homogeneous phantom series (BRTES-MOD) designed from anthropomorphic measurements of a screening mammography population and whose elemental composition was referenced to International Commission on Radiation Units and Measurements Report 44 and 46 tissues. The patient fibroglandular content, compressed breast thickness along with unit parameters and spectrum half-value layer were used to derive the currently used dose conversion factor (DgN). The study showed that the use of a homogeneous phantom, patient compressed breast lateral dimensions and patient anatomical features can affect AGD by as much as 12%, 3% and 1%, respectively. The protocol was found to be superior to existing methodologies. The clinical dosimetry protocol developed in this study can reliably predict the AGD imparted to an individual patient during a routine screening mammogram.

  4. When defense backfires: Detrimental effect of a plant’s protective trichomes on an insect beneficial to the plant

    PubMed Central

    Eisner, Thomas; Eisner, Maria; Hoebeke, E. Richard

    1998-01-01

    The plant Mentzelia pumila (family Loasaceae) has leaves and stems densely covered with tiny hooked trichomes. The structures entrap and kill insects and therefore are most probably protective. But they are also maladaptive in that they incapacitate a coccinellid beetle (Hippodamia convergens) that preys upon an aphid enemy (Macrosiphum mentzeliae) of the plant. The adaptive benefit provided by the trichomes is evidently offset by a cost. PMID:9539750

  5. [Study on characteristics of non-glandular hairs of cultivated Lonicera japonica].

    PubMed

    Zhang, Shan-shan; Yuan, Yuan; Huang, Lu-qi; Chen, Ping

    2015-02-01

    We collected 22 cultivated population of Lonicera japonica from 17 areas. The characteristics of non-glandular hairs were observed and measured by the scanning electron microscopy. The principal components analysis and correlation analysis were conduct based on length and density of L. japonica. The results showed a significant negative correlation between length and density of non-glandular hairs, and the characteristics of non-glandular was not corrrelated significantly with latitude. The correlation results indicated that the density was a key to separate "Damaohua" and "Jizhuahua". The contribution of climate and soil was important to the cultivated population. This reminded that the characteristics of non-glandular hairs were affected by environmental and genetic interaction. PMID:26084157

  6. Endogenous overexpression of Populus MYB186 increases trichome density, improves insect pest resistance, and impacts plant growth.

    PubMed

    Plett, Jonathan M; Wilkins, Olivia; Campbell, Malcolm M; Ralph, Steven G; Regan, Sharon

    2010-11-01

    Trichomes are specialized epidermal cells that generally play a role in reducing transpiration and act as a deterrent to herbivory. In a screen of activation-tagged Populus tremula × Populus alba 717-1B4 trees, we identified a mutant line, fuzzy, with increased foliar trichome density. This mutant also had a 35% increase in growth rate and a 200% increase in the rate of photosynthesis as compared with wild-type poplar. The fuzzy mutant had significant resistance to feeding by larvae of the white-spotted tussock moth (Orgyia leucostigma), a generalist insect pest of poplar trees. The fuzzy trichome phenotype is attributable to activation tagging and increased expression of the gene encoding PtaMYB186, which is related to Arabidopsis thaliana MYB106, a known regulator of trichome initiation. The fuzzy phenotype can be recapitulated by overexpressing PtaMYB186 in poplar. PtaMYB186 overexpression results in reconfiguration of the poplar transcriptome, with changes in the transcript abundance of suites of genes that are related to trichome differentiation. It is notable that a plant with misexpression of a gene responsible for trichome development also had altered traits related to growth rate and pest resistance, suggesting that non-intuitive facets of plant development might be useful targets for plant improvement. PMID:20807210

  7. The Trihelix Transcription Factor GTL1 Regulates Ploidy-Dependent Cell Growth in the Arabidopsis Trichome[W][OA

    PubMed Central

    Breuer, Christian; Kawamura, Ayako; Ichikawa, Takanari; Tominaga-Wada, Rumi; Wada, Takuji; Kondou, Youichi; Muto, Shu; Matsui, Minami; Sugimoto, Keiko

    2009-01-01

    Leaf trichomes in Arabidopsis thaliana develop through several distinct cellular processes, such as patterning, differentiation, and growth. Although recent studies have identified several key transcription factors as regulating early patterning and differentiation steps, it is still largely unknown how these regulatory proteins mediate subsequent trichome development, which is accompanied by rapid cell growth and branching. Here, we report a novel trichome mutation in Arabidopsis, which in contrast with previously identified mutants, increases trichome cell size without altering its overall patterning or branching. We show that the corresponding gene encodes a GT-2-LIKE1 (GTL1) protein, a member of the trihelix transcription factor family. GTL1 is present within the nucleus during the postbranching stages of trichome development, and its loss of function leads to an increase in the nuclear DNA content only in trichomes that have completed branching. Our data further demonstrate that the gtl1 mutation modifies the expression of several cell cycle genes and partially rescues the ploidy defects in the cyclin-dependent kinase inhibitor mutant siamese. Taken together, this study provides the genetic evidence for the requirement of transcriptional regulation in the repression of ploidy-dependent plant cell growth as well as for an involvement of GTL trihelix proteins in this regulation. PMID:19717615

  8. Trichomes of tobacco excrete zinc as zinc-substituted calciumcarbonate and other zinc-containing compounds

    SciTech Connect

    Sarret, G.; Harada, E.; Choi, Y-E.; Isaure, M.-P.; Geoffroy, N.; Fakra, S.; Marcus, M.A.; Birschwilks, M.; Clemens, S.; Manceau, A.

    2006-01-01

    Tobacco (Nicotiana tabacum L. cv Xanthi) plants were exposed to toxic levels of zinc (Zn). Zn exposure resulted in toxicity signs in plants, and these damages were partly reduced by a calcium (Ca) supplement. Confocal imaging of intracellular Zn using Zinquin showed that Zn was preferentially accumulated in trichomes. Exposure to Zn and Zn + Ca increased the trichome density and induced the production of Ca/Zn mineral grains on the head cells of trichomes. These grains were aggregates of submicrometer-sized crystals and poorly crystalline material and contained Ca as major element, along with subordinate amounts of Zn, manganese, potassium, chlorine, phosphorus, silicon, and magnesium. Micro x-ray diffraction revealed that the large majority of the grains were composed essentially of metal-substituted calcite (CaCO3). CaCO3 polymorphs (aragonite and vaterite) and CaC2O4 (Ca oxalate) mono- and dihydrate also were identified, either as an admixture to calcite or in separate grains. Some grains did not diffract, although they contained Ca, suggesting the presence of amorphous form of Ca. The presence of Zn-substituted calcite was confirmed by Zn K-edge micro-extended x-ray absorption fine structure spectroscopy. Zn bound to organic compounds and Zn-containing silica and phosphate were also identified by this technique. The proportion of Zn-substituted calcite relative to the other species increased with Ca exposure. The production of Zn-containing biogenic calcite and other Zn compounds through the trichomes is a novel mechanism involved in Zn detoxification. This study illustrates the potential of laterally resolved x-ray synchrotron radiation techniques to study biomineralization and metal homeostasis processes in plants.

  9. Is nectar reabsorption restricted by the stalk cells of floral and extrafloral nectary trichomes?

    PubMed

    Cardoso-Gustavson, P; Davis, A R

    2015-01-01

    Reabsorption is a phase of nectar dynamics that occurs concurrently with secretion; it has been described in floral nectaries that exude nectar through stomata or unicellular trichomes, but has not yet been recorded in extrafloral glands. Apparently, nectar reabsorption does not occur in multicellular secretory trichomes (MST) due to the presence of lipophilic impregnations - which resemble Casparian strips - in the anticlinal walls of the stalk cells. It has been assumed that these impregnations restrict solute movement within MST to occur unidirectionally and exclusively by the symplast, thereby preventing nectar reflux toward the underlying nectary tissues. We hypothesised that reabsorption is absent in nectaries possessing MST. The fluorochrome lucifer yellow (LYCH) was applied to standing nectar of two floral and extrafloral glands of distantly related species, and then emission spectra from nectary sections were systematically analysed using confocal microscopy. Passive uptake of LYCH via the stalk cells to the nectary tissues occurred in all MST examined. Moreover, we present evidence of nectar reabsorption in extrafloral nectaries, demonstrating that LYCH passed the stalk cells of MST, although it did not reach the deepest nectary tissues. Identical (control) experiments performed with neutral red (NR) demonstrated no uptake of this stain by actively secreting MST, whereas diffusion of NR did occur in plasmolysed MST of floral nectaries at the post-secretory phase, indicating that nectar reabsorption by MST is governed by stalk cell physiology. Interestingly, non-secretory trichomes failed to reabsorb nectar. The role of various nectary components is discussed in relation to the control of nectar reabsorption by secretory trichomes. PMID:24987788

  10. The 1963 Hip-Hop Machine: Hip-Hop Pedagogy as Composition.

    ERIC Educational Resources Information Center

    Rice, Jeff

    2003-01-01

    Proposes an alternative invention strategy for research-based argumentative writing. Investigates the coincidental usage of the term "whatever" in hip-hop, theory, and composition studies. Presents a "whatever-pedagogy" identified as "hip-hop pedagogy," a writing practice that models itself after digital sampling's rhetorical strategy of…

  11. HIP HOP for HIV Awareness: Using Hip Hop Culture to Promote Community-Level HIV Prevention

    ERIC Educational Resources Information Center

    Hill, Mandy J.; Hallmark, Camden J.; McNeese, Marlene; Blue, Nike; Ross, Michael W.

    2014-01-01

    The goal of this paper was to determine the effectiveness of the HIP HOP for HIV Awareness intervention, an innovative model utilising an exchange of an HIV test for a hip hop concert ticket, in a metropolitan city among African American youth and young adults. A subset of intervention participants participated in standardised testing, sex…

  12. Chlorsulfuron modifies biosynthesis of acyl Acid substituents of sucrose esters secreted by tobacco trichomes.

    PubMed

    Kandra, L; Wagner, G J

    1990-11-01

    Sucrose esters and duvatrienediol diterpenes are principal constituents formed in and secreted outside head cells of trichomes occurring on surfaces of Nicotiana tabacum. Using trichome-bearing epidermal peels prepared from midveins of N. tabacum cv T.I. 1068 leaves, we found that chlorsulfuron reduced and modified radiolabeling of sucrose ester acyl acids derived from branched-chain amino acid metabolism. The herbicide did not effect formation and exudation of diterpenes which are products of isoprenoid metabolism. Treatment with 1.0 micromolar chlorsulfuron affected 8.5- and 6.3-fold reductions in radiolabeling of methylvaleryl and methylbutyryl groups of sucrose esters, respectively, and concomitant increases of 9- and 9.8-fold in radiolabeling of straight chain valeryl and butyryl groups, respectively. These results and others indicate that inhibition of acetolactate synthase causes an accumulation of 2-oxo-butyric acid that is utilized by enzymes common to Leu biosynthesis to form 2-oxo-valeric acid. Coenzyme A (CoA) activation of this keto acid gives rise to butyryl CoA, which is utilized to form butyryl containing sucrose esters. Alternatively, reutilization of 2-oxo-valeric acid by the same enzymes followed by CoA activation leads to valeryl containing sucrose esters. We propose that in trichome secretory cells synthase, isomerase and dehydrogenase enzymes which catalyze Leu synthesis/degredation in most tissues, convert iso-branched, anteiso-branched and straight-chain keto acids in the formation of sucrose ester acyl groups. PMID:16667871

  13. Chlorsulfuron Modifies Biosynthesis of Acyl Acid Substituents of Sucrose Esters Secreted by Tobacco Trichomes

    PubMed Central

    Kandra, Lili; Wagner, George J.

    1990-01-01

    Sucrose esters and duvatrienediol diterpenes are principal constituents formed in and secreted outside head cells of trichomes occurring on surfaces of Nicotiana tabacum. Using trichome-bearing epidermal peels prepared from midveins of N. tabacum cv T.I. 1068 leaves, we found that chlorsulfuron reduced and modified radiolabeling of sucrose ester acyl acids derived from branched-chain amino acid metabolism. The herbicide did not effect formation and exudation of diterpenes which are products of isoprenoid metabolism. Treatment with 1.0 micromolar chlorsulfuron affected 8.5- and 6.3-fold reductions in radiolabeling of methylvaleryl and methylbutyryl groups of sucrose esters, respectively, and concomitant increases of 9- and 9.8-fold in radiolabeling of straight chain valeryl and butyryl groups, respectively. These results and others indicate that inhibition of acetolactate synthase causes an accumulation of 2-oxo-butyric acid that is utilized by enzymes common to Leu biosynthesis to form 2-oxo-valeric acid. Coenzyme A (CoA) activation of this keto acid gives rise to butyryl CoA, which is utilized to form butyryl containing sucrose esters. Alternatively, reutilization of 2-oxo-valeric acid by the same enzymes followed by CoA activation leads to valeryl containing sucrose esters. We propose that in trichome secretory cells synthase, isomerase and dehydrogenase enzymes which catalyze Leu synthesis/degredation in most tissues, convert iso-branched, anteiso-branched and straight-chain keto acids in the formation of sucrose ester acyl groups. PMID:16667871

  14. Performance evaluation of frequency-hopped spread spectrum multi-hop networks

    NASA Astrophysics Data System (ADS)

    Gluck, J. W.; Geraniotis, Evaggelos A.

    1988-11-01

    Primary and secondary multiple-access interference processes are characterized for multi-hop packet radio networks, in which users are assumed to be Poisson-distributed in the plane and to use frequency hopped spread-spectrum signaling with a receiver-oriented assignment of frequency-hopping patterns. The throughput per node and the average forward progress are then evaluated for frequency-hopped multi-hop networks that employ Random Forward Routing with fixed transmission radius (RFR) and most forward progress routing with fixed transmission radius (MFR). The optimal average number of neighbors and transmission radius are derived for these cases when Reed-Solomon forward-error-control coding with minimum distance decoding or binary convolutional coding with Viterbi decoding is employed.

  15. On transition rates in surface hopping.

    PubMed

    Escartín, J M; Romaniello, P; Stella, L; Reinhard, P-G; Suraud, E

    2012-12-21

    Trajectory surface hopping (TSH) is one of the most widely used quantum-classical algorithms for nonadiabatic molecular dynamics. Despite its empirical effectiveness and popularity, a rigorous derivation of TSH as the classical limit of a combined quantum electron-nuclear dynamics is still missing. In this work, we aim to elucidate the theoretical basis for the widely used hopping rules. Naturally, we concentrate thereby on the formal aspects of the TSH. Using a Gaussian wave packet limit, we derive the transition rates governing the hopping process at a simple avoided level crossing. In this derivation, which gives insight into the physics underlying the hopping process, some essential features of the standard TSH algorithm are retrieved, namely (i) non-zero electronic transition rate ("hopping probability") at avoided crossings; (ii) rescaling of the nuclear velocities to conserve total energy; (iii) electronic transition rates linear in the nonadiabatic coupling vectors. The well-known Landau-Zener model is then used for illustration. PMID:23267477

  16. Transcriptome analysis approaches for the isolation of trichome-specific genes from the medicinal plant Cistus creticus subsp. creticus.

    PubMed

    Falara, Vasiliki; Fotopoulos, Vasileios; Margaritis, Thanasis; Anastasaki, Thalia; Pateraki, Irene; Bosabalidis, Artemios M; Kafetzopoulos, Dimitris; Demetzos, Costas; Pichersky, Eran; Kanellis, Angelos K

    2008-12-01

    Cistus creticus subsp. creticus is a plant of intrinsic scientific interest due to the distinctive pharmaceutical properties of its resin. Labdane-type diterpenes, the main constituents of the resin, exhibit considerable antibacterial and cytotoxic activities. In this study chemical analysis of isolated trichomes from different developmental stages revealed that young leaves of 1-2 cm length displayed the highest content of labdane-type diterpenes (80 mg/g fresh weight) whereas trichomes from older leaves (2-3 or 3-4 cm) exhibited gradual decreased concentrations. A cDNA library was constructed enriched in transcripts from trichomes isolated from young leaves, which are characterized by high levels of labdane-type diterpenes. Functional annotation of 2,022 expressed sequence tags (ESTs) from the trichome cDNA library based on homology to A. thaliana genes suggested that 8% of the putative identified sequences were secondary metabolism-related and involved primarily in flavonoid and terpenoid biosynthesis. A significant proportion of the ESTs (38%) displayed no significant similarity to any other DNA deposited in databases, indicating a yet unknown function. Custom DNA microarrays constructed with 1,248 individual clones from the cDNA library facilitated transcriptome comparisons between trichomes and trichome-free tissues. In addition, gene expression studies in various Cistus tissues and organs for one of the genes highlighted as the most differentially expressed by the microarray experiments revealed a putative sesquiterpene synthase with a trichome-specific expression pattern. Full length cDNA isolation and heterologous expression in E. coli followed by biochemical analysis, led to the characterization of the produced protein as germacrene B synthase. PMID:18819010

  17. Computation of the glandular radiation dose in digital tomosynthesis of the breast

    PubMed Central

    Sechopoulos, Ioannis; Suryanarayanan, Sankararaman; Vedantham, Srinivasan; D’Orsi, Carl; Karellas, Andrew

    2008-01-01

    Tomosynthesis of the breast is currently a topic of intense interest as a logical next step in the evolution of digital mammography. This study reports on the computation of glandular radiation dose in digital tomosynthesis of the breast. Previously, glandular dose estimations in tomosynthesis have been performed using data from studies of radiation dose in conventional planar mammography. This study evaluates, using Monte Carlo methods, the normalized glandular dose (DgN) to the breast during a tomosynthesis study, and characterizes its dependence on breast size, tissue composition, and x-ray spectrum. The conditions during digital tomosynthesis imaging of the breast were simulated using a computer program based on the Geant4 toolkit. With the use of simulated breasts of varying size, thickness and tissue composition, the DgN to the breast tissue was computed for varying x-ray spectra and tomosynthesis projection angle. Tomosynthesis projections centered about both the cranio-caudal (CC) and medio-lateral oblique (MLO) views were simulated. For each projection angle, the ratio of the glandular dose for that projection to the glandular dose for the zero degree projection was computed. This ratio was denoted the relative glandular dose (RGD) coefficient, and its variation under different imaging parameters was analyzed. Within mammographic energies, the RGD was found to have a weak dependence on glandular fraction and x-ray spectrum for both views. A substantial dependence on breast size and thickness was found for the MLO view, and to a lesser extent for the CC view. Although RGD values deviate substantially from unity as a function of projection angle, the RGD averaged over all projections in a complete tomosynthesis study varies from 0.91 to 1.01. The RGD results were fit to mathematical functions and the resulting equations are provided. PMID:17278508

  18. Computation of the glandular radiation dose in digital tomosynthesis of the breast

    SciTech Connect

    Sechopoulos, Ioannis; Suryanarayanan, Sankararaman; Vedantham, Srinivasan; D'Orsi, Carl; Karellas, Andrew

    2007-01-15

    Tomosynthesis of the breast is currently a topic of intense interest as a logical next step in the evolution of digital mammography. This study reports on the computation of glandular radiation dose in digital tomosynthesis of the breast. Previously, glandular dose estimations in tomosynthesis have been performed using data from studies of radiation dose in conventional planar mammography. This study evaluates, using Monte Carlo methods, the normalized glandular dose (D{sub g}N) to the breast during a tomosynthesis study, and characterizes its dependence on breast size, tissue composition, and x-ray spectrum. The conditions during digital tomosynthesis imaging of the breast were simulated using a computer program based on the Geant4 toolkit. With the use of simulated breasts of varying size, thickness and tissue composition, the D{sub g}N to the breast tissue was computed for varying x-ray spectra and tomosynthesis projection angle. Tomosynthesis projections centered about both the cranio-caudal (CC) and medio-lateral oblique (MLO) views were simulated. For each projection angle, the ratio of the glandular dose for that projection to the glandular dose for the zero degree projection was computed. This ratio was denoted the relative glandular dose (RGD) coefficient, and its variation under different imaging parameters was analyzed. Within mammographic energies, the RGD was found to have a weak dependence on glandular fraction and x-ray spectrum for both views. A substantial dependence on breast size and thickness was found for the MLO view, and to a lesser extent for the CC view. Although RGD values deviate substantially from unity as a function of projection angle, the RGD averaged over all projections in a complete tomosynthesis study varies from 0.91 to 1.01. The RGD results were fit to mathematical functions and the resulting equations are provided.

  19. Landau-Zener type surface hopping algorithms.

    PubMed

    Belyaev, Andrey K; Lasser, Caroline; Trigila, Giulio

    2014-06-14

    A class of surface hopping algorithms is studied comparing two recent Landau-Zener (LZ) formulas for the probability of nonadiabatic transitions. One of the formulas requires a diabatic representation of the potential matrix while the other one depends only on the adiabatic potential energy surfaces. For each classical trajectory, the nonadiabatic transitions take place only when the surface gap attains a local minimum. Numerical experiments are performed with deterministically branching trajectories and with probabilistic surface hopping. The deterministic and the probabilistic approach confirm the affinity of both the LZ probabilities, as well as the good approximation of the reference solution computed by solving the Schrödinger equation via a grid based pseudo-spectral method. Visualizations of position expectations and superimposed surface hopping trajectories with reference position densities illustrate the effective dynamics of the investigated algorithms. PMID:24929375

  20. Epigenetic Stability of Cryopreserved and Cold-Stored Hops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three hop accessions representative of commercially cultivated hops were selected for the analysis of epigenetic stability; females of different origins, including a cultivar developed in New Zealand (Calicross) from American cultivars, a landrace derived European cultivar (Tardif de Bourgogne), and...

  1. Leg stiffness adjustment during hopping at different intensities and frequencies.

    PubMed

    Mrdakovic, Vladimir; Ilic, Dusko; Vulovic, Radun; Matic, Milan; Jankovic, Nenad; Filipovic, Nenad

    2014-01-01

    Understanding leg and joint stiffness adjustment during maximum hopping may provide important information for developing more effective training methods. It has been reported that ankle stiffness has major influence on stable spring-mass dynamics during submaximal hopping, and that knee stiffness is a major determinant for hopping performance during maximal hopping task. Furthermore, there are no reports on how the height of the previous hop could affect overall stiffness modulation of the subsequent maximum one. The purpose of the present study was to determine whether and how the jump height of the previous hop affects leg and joint stiffness for subsequent maximum hop. Ten participants completed trials in which they repeatedly hopped as high as possible (MX task) and trials in which they were instructed to perform several maximum hops with 3 preferred (optimal) height hops between each of them (P3MX task). Both hopping tasks were performed at 2.2 Hz hopping frequency and at the participant's preferred (freely chosen) frequency as well. By comparing results of those hopping tasks, we found that ankle stiffness at 2.2 Hz ( p = 0.041) and knee stiffness at preferred frequency ( p = 0.045) was significantly greater for MX versus P3MX tasks. Leg stiffness for 2.2 Hz hopping is greater than for the preferred frequency. Ankle stiffness is greater for 2.2 Hz than for preferred frequencies; opposite stands for knee stiffness. The results of this study suggest that preparatory hop height can be considered as an important factor for modulation of maximum hop. PMID:25308379

  2. A Case Study: Significance, Epidemiology, and Management of Hop Viruses.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hop latent carlavirus (HpLV), Hop mosaic carlavirus (HpMV), and Apple mosaic ilarvirus (ApMV) are viruses that have been shown to have deleterious effects on cone yield and brewing organic acids in several cultivars in Australian hop gardens, and pose a significant threat to the continued production...

  3. Revolutionizing Environmental Education through Indigenous Hip Hop Culture

    ERIC Educational Resources Information Center

    Gorlewski, Julie; Porfilio, Brad J.

    2012-01-01

    Based upon the life histories of six Indigenous hip hop artists of the Beat Nation artist collective, this essay captures how Indigenous hip hop has the potential to revolutionize environmental education. Hip hop provides Indigenous youth an emancipatory space to raise their opposition to neocolonial controls of Indigenous territories that…

  4. Hip-Hopping across China: Intercultural Formulations of Local Identities

    ERIC Educational Resources Information Center

    Barrett, Catrice

    2012-01-01

    The linguistic dimensions of globalized hip-hop cannot be understood simply as a byproduct of English as an American export. As hip-hop mobilizes, it is common (and arguably necessary) for global hip-hop communities to struggle through purposeful, semiotically rooted dialectics over what constitutes "authentic" and respectable forms of local…

  5. Genomics of the hop psuedo-autosomal regions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hop is one of the few crop species with female and male plants with sex being determined by either XX or XY chromosomes. Hop cones are only produced in female hops with or without fertilization. This has lead to most genomic research being directed toward female plants. Very little work has been don...

  6. HPLC Analysis of [Alpha]- and [Beta]-Acids in Hops

    ERIC Educational Resources Information Center

    Danenhower, Travis M.; Force, Leyna J.; Petersen, Kenneth J.; Betts, Thomas A.; Baker, Gary A.

    2008-01-01

    Hops have been used for centuries to impart aroma and bitterness to beer. The cones of the female hop plant contain both essential oils, which include many of the fragrant components of hops, and a collection of compounds known as [alpha]- and [beta]-acids that are the precursors to bittering agents. In order for brewers to predict the ultimate…

  7. Suppression of Hop Looper (Lepidoptera: Noctuidae) by the fungicide Pyraclostrobin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The hop looper, Hypena humuli Harris, is a reemergent pest of hop that often requires treatment to mitigate crop damage. In four years of field trials, plots treated with fungicides were observed to sustain less hop looper defoliation as compared to nontreated plots. Further investigation revealed...

  8. Communication: Fully coherent quantum state hopping

    SciTech Connect

    Martens, Craig C.

    2015-10-14

    In this paper, we describe a new and fully coherent stochastic surface hopping method for simulating mixed quantum-classical systems. We illustrate the approach on the simple but unforgiving problem of quantum evolution of a two-state quantum system in the limit of unperturbed pure state dynamics and for dissipative evolution in the presence of both stationary and nonstationary random environments. We formulate our approach in the Liouville representation and describe the density matrix elements by ensembles of trajectories. Population dynamics are represented by stochastic surface hops for trajectories representing diagonal density matrix elements. These are combined with an unconventional coherent stochastic hopping algorithm for trajectories representing off-diagonal quantum coherences. The latter generalizes the binary (0,1) “probability” of a trajectory to be associated with a given state to allow integers that can be negative or greater than unity in magnitude. Unlike existing surface hopping methods, the dynamics of the ensembles are fully entangled, correctly capturing the coherent and nonlocal structure of quantum mechanics.

  9. The Rap on Hip-Hop

    ERIC Educational Resources Information Center

    Piekarski, Bill

    2004-01-01

    From its humble origins some 30 years ago in New York's bombed-out, poverty-ravaged South Bronx, hip-hop has risen to become a dominant cultural force both here and abroad. Strictly defined, the term refers to the entire cultural constellation that accompanies rap music, which in 2001 surpassed country music as the most popular musical genre in…

  10. Injury incidence in hip hop dance.

    PubMed

    Ojofeitimi, S; Bronner, S; Woo, H

    2012-06-01

    Hip hop dance has rapidly become a popular international art form. There is limited information on injury patterns in this population. The purpose of this study was to determine injury incidence and patterns among three groups of hip hop dancers. Three hundred and twelve intermediate, advanced, and expert hip hop dancers were recruited at battles, dance conferences, clubs, and on dance related web sites within the United States and internationally. A Web-based survey was conducted over a 6-month period. Inclusion criteria included intermediate and advanced level dancers over the age of 13. Dancers were divided into three main categories: Breakers, Popper/Lockers, and New Schoolers. Separate analysis of variances were used to compare injury pattern differences between groups. Two hundred and thirty-two dancers reported a total of 738 injuries. Five hundred and six of these (sustained by 205 dancers) were time-loss (TL) injuries. Annual injury incidence was 237% (162% involving TL). Lower extremity injuries were 52% and upper extremity injuries 32% of total injuries. Breakers had a higher injury incidence compared with Popper/Lockers, and New Schoolers. Hip hop dancers report injury rates that are higher than other dance forms but similar to gymnastics. These dancers should be educated concerning injury prevention, biomechanics, and use of protective equipment. PMID:20807386

  11. Multimodal Hip Hop Productions as Media Literacies

    ERIC Educational Resources Information Center

    Turner, K. C. Nat

    2012-01-01

    This study draws on ethnographic data from a year-long multimodal media production (MMP) course and the experience of an African American female adolescent who used the production of multimodal Hip Hop texts to express her creativity and growing socially conscious view of the world. The study demonstrates how students made meaning multimodally and…

  12. Forecasting and management of hop downy mildew

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Downy mildew of hop, caused by Pseudoperonospora humuli, is managed in the Pacific Northwestern U.S. by regular application of fungicides. A degree-day model that forecasts the first emergence of shoots systemically infection with P. humuli (termed basal spikes) and a risk index for secondary sprea...

  13. Communication: Fully coherent quantum state hopping

    NASA Astrophysics Data System (ADS)

    Martens, Craig C.

    2015-10-01

    In this paper, we describe a new and fully coherent stochastic surface hopping method for simulating mixed quantum-classical systems. We illustrate the approach on the simple but unforgiving problem of quantum evolution of a two-state quantum system in the limit of unperturbed pure state dynamics and for dissipative evolution in the presence of both stationary and nonstationary random environments. We formulate our approach in the Liouville representation and describe the density matrix elements by ensembles of trajectories. Population dynamics are represented by stochastic surface hops for trajectories representing diagonal density matrix elements. These are combined with an unconventional coherent stochastic hopping algorithm for trajectories representing off-diagonal quantum coherences. The latter generalizes the binary (0,1) "probability" of a trajectory to be associated with a given state to allow integers that can be negative or greater than unity in magnitude. Unlike existing surface hopping methods, the dynamics of the ensembles are fully entangled, correctly capturing the coherent and nonlocal structure of quantum mechanics.

  14. The Philippine "Hip Hop Stick Dance"

    ERIC Educational Resources Information Center

    Lewis, Lisa

    2012-01-01

    This article introduces a dance that blends the traditional cultural heritage of the Philippines with modern music and moves. "Hip Hop Stick Dance" incorporates Tinikling (the Philippine national dance) and Arnis (a Filipino style of martial arts) to create a contemporary combination of rhythm, dance, and fitness. It was designed to introduce…

  15. Hopping Diffusion of Nanoparticles in Polymer Matrices

    PubMed Central

    2016-01-01

    We propose a hopping mechanism for diffusion of large nonsticky nanoparticles subjected to topological constraints in both unentangled and entangled polymer solids (networks and gels) and entangled polymer liquids (melts and solutions). Probe particles with size larger than the mesh size ax of unentangled polymer networks or tube diameter ae of entangled polymer liquids are trapped by the network or entanglement cells. At long time scales, however, these particles can diffuse by overcoming free energy barrier between neighboring confinement cells. The terminal particle diffusion coefficient dominated by this hopping diffusion is appreciable for particles with size moderately larger than the network mesh size ax or tube diameter ae. Much larger particles in polymer solids will be permanently trapped by local network cells, whereas they can still move in polymer liquids by waiting for entanglement cells to rearrange on the relaxation time scales of these liquids. Hopping diffusion in entangled polymer liquids and networks has a weaker dependence on particle size than that in unentangled networks as entanglements can slide along chains under polymer deformation. The proposed novel hopping model enables understanding the motion of large nanoparticles in polymeric nanocomposites and the transport of nano drug carriers in complex biological gels such as mucus. PMID:25691803

  16. Inhibition of human cytochrome P450 enzymes by hops (Humulus lupulus) and hop prenylphenols

    PubMed Central

    Nikolić, Dejan; Chen, Shao-Nong; Huang, Ke; Li, Guannan; Pauli, Guido F.; van Breemen, Richard B.

    2014-01-01

    As hops (Humulus lupulus L.) are used in the brewing of beer and by menopausal women as estrogenic dietary supplements, the potential for hop extracts and hop constituents to cause drug-botanical interactions by inhibiting human cytochrome P450 enzymes was investigated. Inhibition of major human cytochrome P450 enzymes by a standardized hop extract and isolated hop prenylated phenols was evaluated using a fast and efficient assay based on ultrahigh pressure liquid chromatography-tandem mass spectrometry. The hop extract at 5 μg/mL inhibited CYP2C8 (93%), CYP2C9 (88%), CYP2C19 (70%), and CYP1A2 (27%) with IC50 values of 0.8, 0.9, 3.3, and 9.4 μg/mL, respectively, but time-dependent inactivation was observed only for CYP1A2. Isoxanthohumol from hops was the most potent inhibitor of CYP2C8 with an IC50 of 0.2 μM, whereas 8-prenylnaringenin was the most potent inhibitor of CYP1A2, CYP2C9 and CYP2C19 with IC50 values of 1.1 μM, 1.1 μM and 0.4 μM, respectively. Extracts of hops contain prenylated compounds such as the flavanones isoxanthohumol and 8-prenylnaringenin and the chalcone xanthohumol that can inhibit CYP450s, especially the CYP2C family, which may affect the efficacy and safety of some CYP2C substrate drugs when co-administered. PMID:24342125

  17. Inhibition of human cytochrome P450 enzymes by hops (Humulus lupulus) and hop prenylphenols.

    PubMed

    Yuan, Yang; Qiu, Xi; Nikolić, Dejan; Chen, Shao-Nong; Huang, Ke; Li, Guannan; Pauli, Guido F; van Breemen, Richard B

    2014-03-12

    As hops (Humulus lupulus L.) are used in the brewing of beer and by menopausal women as estrogenic dietary supplements, the potential for hop extracts and hop constituents to cause drug-botanical interactions by inhibiting human cytochrome P450 enzymes was investigated. Inhibition of major human cytochrome P450 enzymes by a standardized hop extract and isolated hop prenylated phenols was evaluated using a fast and efficient assay based on ultrahigh pressure liquid chromatography-tandem mass spectrometry. The hop extract at 5 μg/mL inhibited CYP2C8 (93%), CYP2C9 (88%), CYP2C19 (70%), and CYP1A2 (27%) with IC50 values of 0.8, 0.9, 3.3, and 9.4 μg/mL, respectively, but time-dependent inactivation was observed only for CYP1A2. Isoxanthohumol from hops was the most potent inhibitor of CYP2C8 with an IC50 of 0.2 μM, whereas 8-prenylnaringenin was the most potent inhibitor of CYP1A2, CYP2C9 and CYP2C19 with IC50 values of 1.1 μM, 1.1 μM and 0.4 μM, respectively. Extracts of hops contain prenylated compounds such as the flavanones isoxanthohumol and 8-prenylnaringenin and the chalcone xanthohumol that can inhibit CYP450s, especially the CYP2C family, which may affect the efficacy and safety of some CYP2C substrate drugs when co-administered. PMID:24342125

  18. Cell Wall Maturation of Arabidopsis Trichomes Is Dependent on Exocyst Subunit EXO70H4 and Involves Callose Deposition1[OPEN

    PubMed Central

    Kulich, Ivan; Vojtíková, Zdeňka; Glanc, Matouš; Ortmannová, Jitka; Rasmann, Sergio; Žárský, Viktor

    2015-01-01

    Arabidopsis (Arabidopsis thaliana) leaf trichomes are single-cell structures with a well-studied development, but little is understood about their function. Developmental studies focused mainly on the early shaping stages, and little attention has been paid to the maturation stage. We focused on the EXO70H4 exocyst subunit, one of the most up-regulated genes in the mature trichome. We uncovered EXO70H4-dependent development of the secondary cell wall layer, highly autofluorescent and callose rich, deposited only in the upper part of the trichome. The boundary is formed between the apical and the basal parts of mature trichome by a callose ring that is also deposited in an EXO70H4-dependent manner. We call this structure the Ortmannian ring (OR). Both the secondary cell wall layer and the OR are absent in the exo70H4 mutants. Ecophysiological aspects of the trichome cell wall thickening include interference with antiherbivore defense and heavy metal accumulation. Ultraviolet B light induces EXO70H4 transcription in a CONSTITUTIVE PHOTOMORPHOGENIC1-dependent way, resulting in stimulation of trichome cell wall thickening and the OR biogenesis. EXO70H4-dependent trichome cell wall hardening is a unique phenomenon, which may be conserved among a variety of the land plants. Our analyses support a concept that Arabidopsis trichome is an excellent model to study molecular mechanisms of secondary cell wall deposition. PMID:25767057

  19. HopRec: Hop-Based Recommendation Ability Enhanced Reputation Ranking in P2P Networks

    NASA Astrophysics Data System (ADS)

    Wang, Yufeng; Nakao, Akihiro; Ma, Jianhua

    As a concept stemmed from social field, we argued that, in P2P networks, peers' recommendation behaviors and functional behaviors should be explicitly separated, thus we propose the HopRec scheme which uses hop-based recommendation ability to improve the accuracy of reputation ranking in P2P networks. Our contributions lie in the following aspects: firstly, we adopt the simple but effective idea to infer peer's recommendation ability (RA): the farer away that peer is from the initial malicious seeds, the higher RA that peer should have; Then, the computation of reputation rankings appropriately reflects peer's different RA. The simulation results show that, in comparison with Eigentrust-like algorithms, HopRec can be robust to sybils and front peers attacks, and achieve significant performance improvement. Moreover, we compare HopRec with two related schemes, Poisonedwater and CredibleRank, and found that: in hospitable P2P environment, HopRec can obtain better performance than Poisonedwater, and can achieve the comparable performance as CredibleRank, with less computation overhead then CredibleRank. Finally, we also show that, if the initial good and malicious seeds could be selected based on peers' degrees, then HopRec and CredibleRank can achieve perfect performance.

  20. The Formation of "Hip-Hop Academicus"--How American Scholars Talk about the Academisation of Hip-Hop

    ERIC Educational Resources Information Center

    Soderman, Johan

    2013-01-01

    Social activism and education have been associated with hip-hop since it emerged in New York City 38 years ago. Therefore, it might not be surprising that universities have become interested in hip-hop. This article aims to highlight this "hip-hop academisation" and analyse the discursive mechanisms that manifest in these academisation…

  1. Featherless Dinosaurs and the Hip-Hop Simulacrum: Reconsidering Hip-Hop's Appropriateness for the Music Classroom

    ERIC Educational Resources Information Center

    Kruse, Adam J.

    2016-01-01

    This article offers considerations for music teachers interested in including hip-hop music in their classrooms but who might feel concerned with or overwhelmed by issues of appropriateness. Two concerns related to hip-hop music are examined: language and negative social themes. Commercial interests in hip-hop music have created a simulacrum (or…

  2. Phase diagram of hopping conduction mechanisms in polymer nanofiber network

    SciTech Connect

    Li, Jeng-Ting; Lu, Yu-Cheng; Jiang, Shiau-Bin; Zhong, Yuan-Liang; Yeh, Jui-Ming

    2015-12-07

    Network formation by nanofiber crosslinking is usually in polymer materials as application in organic semiconductor devices. Electron hopping transport mechanisms depend on polymer morphology in network. Conducting polymers morphology in a random network structure is modeled by a quasi-one-dimensional system coupled of chains or fibers. We observe the varying hopping conduction mechanisms in the polyaniline nanofibers of the random network structure. The average diameter d of the nanofibers is varied from approximately 10 to 100 nm. The different dominant hopping mechanisms including Efros-Shklovskii variable-range hopping (VRH), Mott VRH, and nearest-neighbor hopping are dependent on temperature range and d in crossover changes. The result of this study is first presented in a phase diagram of hopping conduction mechanisms based on the theories of the random network model. The hopping conduction mechanism is unlike in normal semiconductor materials.

  3. Filamentous Trichomic Prokaryotes in Carbonaceous Meteorites: Indigenous Microfossils, Minerals, or Modern Bio-Contaminants?

    NASA Technical Reports Server (NTRS)

    Hoover, Richard B.; Rozanov, Alexei Yu.

    2011-01-01

    Large complex filaments have been detected in freshly fractured interior surfaces of a variety of carbonaceous meteorites. Many exhibit the detailed morphological and morphometric characteristics of known filamentous trichomic prokaryotic microorganisms. In this paper we review prior studies of filamentous microstructures encountered in the meteorites along with the elemental compositions and characteristics of the, fibrous evaporite minerals and filamentous cyanobacteria and homologous trichomic sulfur bacteria. The meteorite images and elemental compositions will compared with data obtained with the same instruments for abiotic microstructures and living and fossil microorganisms in order to evaluate the relative merits of the alternate hypotheses that have been advanced to explain the nature and characteristics of the meteorite filaments. The possibiility that the filaments found in the meteorites may be comprise modern bio-contaminants will be evaluated in light of their observed elemental compositions and data by other researchers on the detection of indigenous complex organic biosignatures, and extraterrestrial amino acids and nucleobases found in the Murchison CM2 and the Orgueil CI1 carbonaceous meteorites.

  4. A trichome-specific linoleate lipoxygenase expressed during pyrethrin biosynthesis in pyrethrum.

    PubMed

    Ramirez, Aldana M; Yang, Ting; Bouwmeester, Harro J; Jongsma, Maarten A

    2013-10-01

    The lipid precursor alcohols of pyrethrins-jasmolone, pyrethrolone and cinerolone-have been proposed as sharing parts of the oxylipin pathway with jasmonic acid. This implies that one of the first committed steps of pyrethrin biosynthesis is catalyzed by a lipoxygenase, catalyzing the hydroperoxidation of linolenic acid at position 13. Previously, we showed that the expression and activity of chrysanthemyl diphosphate synthase (TcCDS), the enzyme catalyzing the first committed step in the biosynthesis of the acid moiety of pyrethrins, is trichome-specific and developmentally regulated in flowers. In the present study we characterized the expression pattern of 25 lipoxygenase EST contigs, and subsequently carried out the molecular cloning of two pyrethrum lipoxygenases, TcLOX1 and TcLOX2, that have a similar pattern to TcCDS. Only recombinant TcLOX1 catalyzed the peroxidation of the linolenic acid substrate. Just as TcCDS, TcLOX1, are exclusively expressed in trichomes. Phylogenetic analysis showed that the enzyme shared the highest homology with chloroplast-localized 13-type-lipoxygenases that are involved in maintaining basal levels of jasmonate. PMID:23893337

  5. Method for the evaluation of a average glandular dose in mammography

    SciTech Connect

    Okunade, Akintunde Akangbe

    2006-04-15

    This paper concerns a method for accurate evaluation of average glandular dose (AGD) in mammography. At different energies, the interactions of photons with tissue are not uniform. Thus, optimal accuracy in the estimation of AGD is achievable when the evaluation is carried out using the normalized glandular dose values, g(x,E), that are determined for each (monoenergetic) x-ray photon energy, E, compressed breast thickness (CBT), x, breast glandular composition, and data on photon energy distribution of the exact x-ray beam used in breast imaging. A generalized model for the values of g(x,E) that is for any arbitrary CBT ranging from 2 to 9 cm (with values that are not whole numbers inclusive, say, 4.2 cm) was developed. Along with other dosimetry formulations, this was integrated into a computer software program, GDOSE.FOR, that was developed for the evaluation of AGD received from any x-ray tube/equipment (irrespective of target-filter combination) of up to 50 kVp. Results are presented which show that the implementation of GDOSE.FOR yields values of normalized glandular dose that are in good agreement with values obtained from methodologies reported earlier in the literature. With the availability of a portable device for real-time acquisition of spectra, the model and computer software reported in this work provide for the routine evaluation of AGD received by a specific woman of known age and CBT.

  6. [About a case of a recurrent glandular cardiac myxoma in a child].

    PubMed

    Meurgey, Alexandra; Henaine, Roland; Bouvagnet, Patrice; Chalabreysse, Lara

    2016-06-01

    Primary cardiac tumors are extremely rare and mainly benign. The majority of these are myxomas (40%). Myxoma are generally sporadic tumors which occur most commonly in adult females between 30 and 40 years, and are seldom found in the paediatric population (5%). Seven percent are associated with igenetic diseases. We report the case of an eight-year-old boy presenting a recurrent glandular cardiac myxoma. In 2011, he presented a deterioration of the general state. An echocardiography highlighted a left atrial mass on the interatrial septum, with a pedicular insertion. On the microscope, it consisted of a proliferation of stellate cells isolated or clustered in rudimentary vessels in a myxoid stroma presenting haemorrhage changes. These cells expressed CD34 and calretinine. Glandular elements without atypia were clustered within the myxomatous proliferation. They expressed cytokeratin (CK) 7. Surgical resection was macroscopically complete. In 2014, the boy had a sudden neurological deficit during a football match. An echocardiography revealed a recurrence at the same location. The lesion was excised and addressed in several fragments. Classical myxoma was associated with glands without atypia. This last component expressed CKAE1/AE3 and CK7. Ki67 index of proliferation was low. The surgical reintervention was macroscopically complete. The final diagnosis was glandular cardiac myxoma. A genetic survey was conducted, showing the presence of Carney complex. This is the first description in the litterature of a recurrent glandular cardiac myxoma occuring in a child. PMID:27234518

  7. Hypercalcemic encephalopathy in a patient on anti-TB treatment for glandular tuberculosis.

    PubMed

    Abraham, G; Sadasivam, P B; Gaspar, J H; Isphani, N; Lawrence, R

    1992-08-01

    An 84 years old male patient presented with hypercalcemic encephalopathy and mild azotemia while on anti-tuberculous treatment for glandular tuberculosis. He recovered fully during treatment with hydration, intravenous frusemide and oral prednisolone while continuing on the antituberculous therapy. PMID:1308493

  8. Critical Hamiltonians with long range hopping

    NASA Astrophysics Data System (ADS)

    Levitov, L. S.

    1999-11-01

    Critical states are studied by a real space RG in the problem with strong diagonal disorder and long range power law hopping. The RG ow of the distribution of coupling parameters is characterized by a family of non-trivial fix points. We consider the RG flow of the distribution of participation ratios of eigenstates. Scaling of participation ratios is sensitive to the nature of the RG fix point. For some fix points, scaling of participation ratios is characterized by a distribution of exponents, rather than by a single exponent.The RG method can be generalized to treat certain fermionic Hamiltonians with disorder and long range hopping. We derive the RG for a model of interacting two-level systems. Besides couplings, in this problem the RG includes the density of states. The density of states is renormalized so that it develops a singularity near zero energy.

  9. Bipolaron Hopping Conduction in Boron Carbides

    SciTech Connect

    ASELAGE, TERRENCE L.; EMIN, D.; MCCREADY, STEVEN S.

    1999-09-20

    The electrical conductivities of boron carbides, B{sub 12+x}C{sub 3{minus}x} with 0.1 < x < 1.7, between 300 and 1200K suggest the hopping of a nearly temperature-independent density of small (bi)polarons. The activation energies of the nobilities are low, {approx} 0.16 eV, and are nearly independent of the composition. At lower temperatures, conductivities have non-Arrhenius temperature dependencies and strong sensitivity to carbon concentration. Percolative aspects of low-temperature hopping are evident in this sensitivity to composition. Boron carbides' Seebeck coefficients are anomalous in that (1) they are much larger than expected from boron carbides' large carrier densities and (2) they depend only weakly on the carrier density. Carrier-induced softening of local vibrations gives contributions to the Seebeck coefficient that mirror the magnitudes and temperature dependencies found in boron carbides.

  10. An Efficient Next Hop Selection Algorithm for Multi-Hop Body Area Networks

    PubMed Central

    Ayatollahitafti, Vahid; Ngadi, Md Asri; Mohamad Sharif, Johan bin; Abdullahi, Mohammed

    2016-01-01

    Body Area Networks (BANs) consist of various sensors which gather patient’s vital signs and deliver them to doctors. One of the most significant challenges faced, is the design of an energy-efficient next hop selection algorithm to satisfy Quality of Service (QoS) requirements for different healthcare applications. In this paper, a novel efficient next hop selection algorithm is proposed in multi-hop BANs. This algorithm uses the minimum hop count and a link cost function jointly in each node to choose the best next hop node. The link cost function includes the residual energy, free buffer size, and the link reliability of the neighboring nodes, which is used to balance the energy consumption and to satisfy QoS requirements in terms of end to end delay and reliability. Extensive simulation experiments were performed to evaluate the efficiency of the proposed algorithm using the NS-2 simulator. Simulation results show that our proposed algorithm provides significant improvement in terms of energy consumption, number of packets forwarded, end to end delay and packet delivery ratio compared to the existing routing protocol. PMID:26771586

  11. Automatic glandular and tubule region segmentation in histological grading of breast cancer

    NASA Astrophysics Data System (ADS)

    Nguyen, Kien; Barnes, Michael; Srinivas, Chukka; Chefd'hotel, Christophe

    2015-03-01

    In the popular Nottingham histologic score system for breast cancer grading, the pathologist analyzes the H and E tissue slides and assigns a score, in the range of 1-3, for tubule formation, nuclear pleomorphism and mitotic activity in the tumor regions. The scores from these three factors are added to give a final score, ranging from 3-9 to grade the cancer. Tubule score (TS), which reflects tubular formation, is a value in 1-3 given by manually estimating the percentage of glandular regions in the tumor that form tubules. In this paper, given an H and E tissue image representing a tumor region, we propose an automated algorithm to detect glandular regions and detect the presence of tubules in these regions. The algorithm first detects all nuclei and lumen candidates in the input image, followed by identifying tumor nuclei from the detected nuclei and identifying true lumina from the lumen candidates using a random forest classifier. Finally, it forms the glandular regions by grouping the closely located tumor nuclei and lumina using a graph-cut-based method. The glandular regions containing true lumina are considered as the ones that form tubules (tubule regions). To evaluate the proposed method, we calculate the tubule percentage (TP), i.e., the ratio of the tubule area to the total glandular area for 353 H and E images of the three TSs, and plot the distribution of these TP values. This plot shows the clear separation among these three scores, suggesting that the proposed algorithm is useful in distinguishing images of these TSs.

  12. Terrific Trichomes (and Other Specialised Cells) in African Violets: How to Get a Lot from One Plant in the Classroom

    ERIC Educational Resources Information Center

    Cottrell, Vicki M.

    2013-01-01

    African violet (genus "Saintpaulia") was identified as a particularly suitable genus for the study of specialised plant cells in the classroom using microscopes. The techniques described here involve simple preparation without staining. The cells and structures that can be investigated include: trichomes (hairs); stomata; guard cells and…

  13. The molecular structure of hop latent viroid (HLV), a new viroid occurring worldwide in hops.

    PubMed Central

    Puchta, H; Ramm, K; Sänger, H L

    1988-01-01

    A new viroid which does not seem to produce any symptoms of disease, and is therefore tentatively named hop latent viroid (HLV) was found to occur worldwide in hops. HLV proved to be infectious when mechanically inoculated onto viroid- and virus-free hops. The viroid nature of HLV was also substantiated by sequence analysis which revealed that HLV is a circular RNA consisting of 256 nucleotides, that can be arranged into the viroid-specific, rod-like secondary structure. HLV also contains the central conserved region typical for most of the presently known viroids. However HLV does not contain the viroid-specific oligo(A) stretch in the upper left part of its rod-like molecule. Because of this feature and a sequence similarity with the prototypes of the other viroid groups below 55%, HLV can be regarded as the first member of a new viroid group. Images PMID:2454454

  14. A New Glabrous Gene (csgl3) Identified in Trichome Development in Cucumber (Cucumis sativus L.).

    PubMed

    Cui, Jin-Ying; Miao, Han; Ding, Li-Hong; Wehner, Todd C; Liu, Pan-Na; Wang, Ye; Zhang, Sheng-Ping; Gu, Xing-Fang

    2016-01-01

    Spines or trichomes on the fruit of cucumbers enhance their commercial value in China. In addition, glabrous mutants exhibit resistance to aphids and therefore their use by growers can reduce pesticide residues. Previous studies have reported two glabrous mutant plants containing the genes, csgl1 and csgl2. In the present study, a new glabrous mutant, NCG157, was identified showing a gene interaction effect with csgl1 and csgl2. This mutant showed the glabrous character on stems, leaves, tendrils, receptacles and ovaries, and there were no spines or tumors on the fruit surface. Inheritance analysis showed that a single recessive gene, named csgl3, determined the glabrous trait. An F2 population derived from the cross of two inbred lines 9930 (a fresh market type from Northern China that exhibits trichomes) and NCG157 (an American processing type with glabrous surfaces) was used for genetic mapping of the csgl3 gene. By combining bulked segregant analysis (BAS) with molecular markers, 18 markers, including two simple sequence repeats (SSR), nine insertion deletions (InDel) and seven derived cleaved amplified polymorphism sequences (dCAPs), were identified to link to the csgl3 gene. All of the linked markers were used as anchor loci to locate the csgl3 gene on cucumber chromosome 6. The csgl3 gene was mapped between the dCAPs markers dCAPs-21 and dCAPs-19, at genetic distances of 0.05 cM and 0.15 cM, respectively. The physical distance of this region was 19.6 kb. Three markers, InDel-19, dCAPs-2 and dCAPs-11, co-segregated with csgl3. There were two candidate genes in the region, Csa6M514860 and Csa6M514870. Quantitative real-time PCR showed that the expression of Csa6M514870 was higher in the tissues of 9930 than that of NCG157, and this was consistent with their phenotypic characters. Csa6M514870 is therefore postulated to be the candidate gene for the development of trichomes in cucumber. This study will facilitate marker-assisted selection (MAS) of the smooth

  15. A New Glabrous Gene (csgl3) Identified in Trichome Development in Cucumber (Cucumis sativus L.)

    PubMed Central

    Ding, Li-Hong; Wehner, Todd C.; Liu, Pan-Na; Wang, Ye; Zhang, Sheng-Ping; Gu, Xing-Fang

    2016-01-01

    Spines or trichomes on the fruit of cucumbers enhance their commercial value in China. In addition, glabrous mutants exhibit resistance to aphids and therefore their use by growers can reduce pesticide residues. Previous studies have reported two glabrous mutant plants containing the genes, csgl1 and csgl2. In the present study, a new glabrous mutant, NCG157, was identified showing a gene interaction effect with csgl1 and csgl2. This mutant showed the glabrous character on stems, leaves, tendrils, receptacles and ovaries, and there were no spines or tumors on the fruit surface. Inheritance analysis showed that a single recessive gene, named csgl3, determined the glabrous trait. An F2 population derived from the cross of two inbred lines 9930 (a fresh market type from Northern China that exhibits trichomes) and NCG157 (an American processing type with glabrous surfaces) was used for genetic mapping of the csgl3 gene. By combining bulked segregant analysis (BAS) with molecular markers, 18 markers, including two simple sequence repeats (SSR), nine insertion deletions (InDel) and seven derived cleaved amplified polymorphism sequences (dCAPs), were identified to link to the csgl3 gene. All of the linked markers were used as anchor loci to locate the csgl3 gene on cucumber chromosome 6. The csgl3 gene was mapped between the dCAPs markers dCAPs-21 and dCAPs-19, at genetic distances of 0.05 cM and 0.15 cM, respectively. The physical distance of this region was 19.6 kb. Three markers, InDel-19, dCAPs-2 and dCAPs-11, co-segregated with csgl3. There were two candidate genes in the region, Csa6M514860 and Csa6M514870. Quantitative real-time PCR showed that the expression of Csa6M514870 was higher in the tissues of 9930 than that of NCG157, and this was consistent with their phenotypic characters. Csa6M514870 is therefore postulated to be the candidate gene for the development of trichomes in cucumber. This study will facilitate marker-assisted selection (MAS) of the smooth

  16. Mineral nutrient uptake from prey and glandular phosphatase activity as a dual test of carnivory in semi-desert plants with glandular leaves suspected of carnivory

    PubMed Central

    Płachno, Bartosz Jan; Adamec, Lubomír; Huet, Hervé

    2009-01-01

    Background and Aims Ibicella lutea and Proboscidea parviflora are two American semi-desert species of glandular sticky plants that are suspected of carnivory as they can catch small insects. The same characteristics might also hold for two semi-desert plants with glandular sticky leaves from Israel, namely Cleome droserifolia and Hyoscyamus desertorum. The presence of proteases on foliar hairs, either secreted by the plant or commensals, detected using a simple test, has long been considered proof of carnivory. However, this test does not prove whether nutrients are really absorbed from insects by the plant. To determine the extent to which these four species are potentially carnivorous, hair secretion of phosphatases and uptake of N, P, K and Mg from fruit flies as model prey were studied in these species and in Roridula gorgonias and Drosophyllum lusitanicum for comparison. All species examined possess morphological and anatomical adaptations (hairs or emergences secreting sticky substances) to catch and kill small insects. Methods The presence of phosphatases on foliar hairs was tested using the enzyme-labelled fluorescence method. Dead fruit flies were applied to glandular sticky leaves of experimental plants and, after 10–15 d, mineral nutrient content in their spent carcasses was compared with initial values in intact flies after mineralization. Key Results Phosphatase activity was totally absent on Hyoscyamus foliar hairs, a certain level of activity was usually found in Ibicella, Proboscidea and Cleome, and a strong response was found in Drosophyllum. Roridula exhibited only epidermal activity. However, only Roridula and Drosophyllum took up nutrients (N, P, K and Mg) from applied fruit flies. Conclusions Digestion of prey and absorption of their nutrients are the major features of carnivory in plants. Accordingly, Roridula and Drosophyllum appeared to be fully carnivorous; by contrast, all other species examined are non-carnivorous as they did not meet

  17. Rethinking Pedagogy in Urban Spaces: Implementing Hip-Hop Pedagogy in the Urban Science Classroom

    ERIC Educational Resources Information Center

    Adjapong, Edmund S.; Emdin, Christopher

    2015-01-01

    A significant amount of research regarding Hip-Hop Based Education (HHBE) fails to provide insight on how to incorporate elements of Hip-Hop into daily teaching practices; rather Hip-Hop based educators focus mainly on incorporating Hip-Hop culture into curricula. This study explores the benefits of using two specific Hip-Hop pedagogical practices…

  18. Hip-Hop Is the Healer: Sense of Belonging and Diversity among Hip-Hop Collegians

    ERIC Educational Resources Information Center

    Sulé, V. Thandi

    2016-01-01

    Sense of belonging is recognized as a factor contributing to persistence to graduation. Furthermore, interactional diversity is associated with learning and civic outcomes--touted higher education goals. Hip-hop culture, one of the most influential cultural creations of the mid-20th century, has succeeded in attracting devotees from diverse…

  19. Pharmacokinetics of Prenylated Hop Phenols in Women Following Oral Administration of a Standardized Extract of Hops

    PubMed Central

    van Breemen, Richard B.; Yuan, Yang; Banuvar, Suzanne; Shulman, Lee P.; Qiu, Xi; Alvarenga, René F. Ramos; Chen, Shao-Nong; Dietz, Birgit M.; Bolton, Judy L.; Pauli, Guido F.; Krause, Elizabeth; Viana, Marlos; Nikolic, Dejan

    2014-01-01

    SCOPE Women seeking alternatives to hormone replacement therapy for menopausal symptoms often try botanical dietary supplements containing extracts of hops (Humulus lupulus L.). Hops contain 8-prenylnaringenin (8-PN), a potent phytoestrogen, the related flavanones 6-prenylnaringenin (6-PN) and isoxanthohumol (IX), and the prenylated chalcone xanthohumol (XN). METHODS AND RESULTS After chemically and biologically standardizing an extract of spent hops to these marker compounds, an escalating dose study was carried out in menopausal women to evaluate safety and pharmacokinetics. 8-PN, 6-PN, IX, and XN, sex hormones, and prothrombin time (PT/INR) were determined in blood samples and/or 24-h urine samples. There was no effect on sex hormones or blood clotting. The maximum serum concentrations of the prenylated phenols were dose-dependent and were reached from 2 to 7 h, indicating slow absorption. The marker compounds formed glucuronides that were found in serum and urine. Secondary peaks at 5 h in the serum concentration-time curves indicated enterohepatic recirculation. The serum concentration-time curves indicated demethylation of IX to form 8-PN and cyclization of XN to IX. Slow absorption and enterohepatic recirculation contributed to half-lives exceeding 20 h. CONCLUSION This human study indicated long half-lives of the estrogenic and proestrogenic prenylated phenols in hops but no acute toxicity. PMID:25045111

  20. Glandular mast cells with distinct phenotype are highly elevated in chronic rhinosinusitis with nasal polyps

    PubMed Central

    Takabayashi, Tetsuji; Kato, Atsushi; Peters, Anju T.; Suh, Lydia A.; Carter, Roderick; Norton, James; Grammer, Leslie C.; Tan, Bruce K.; Chandra, Rakesh K.; Conley, David B.; Kern, Robert C.; Fujieda, Shigeharu; Schleimer, Robert P.

    2012-01-01

    Background Although chronic rhinosinusitis with nasal polyps (CRSwNP) is characterized by Th2 inflammation, the role of mast cells is poorly understood. Objective The objective of this study was to investigate the presence, localization and phenotype of mast cells in patients with chronic rhinosinusitis (CRS). Methods We collected nasal tissue and nasal lavage fluid from patients with CRS and control subjects. We analyzed mRNA for the mast cell proteases tryptase, chymase and carboxypeptidase A3 (CPA3), using real-time PCR, and measured mast cell protease proteins using ELISA, immunohistochemistry, and immunofluorescence. Results Tryptase mRNA was significantly increased in nasal polyps (NPs) from patients with CRSwNP (P < .001) compared with uncinate tissue (UT) from patients with CRS or control subjects. Tryptase protein was also elevated in NPs and in nasal lavage fluids from patients with CRSwNP. Immnohistochemistry showed increased numbers of mast cells in epithelium and glands but not within the lamina propria in NPs. The mast cells detected in epithelium in NPs were characterized by expression of tryptase and CPA3 but not chymase. Mast cells expressing all three proteases were abundant within glandular epithelium of NPs but were not found in normal glandular structures. Conclusion: Herein we demonstrate a unique localization of mast cells within glandular epithelium of NPs, and show that NPs mast cells have distinct phenotypes that vary by tissue location. Glandular mast cells and the diverse subsets of mast cells detected may contribute to the pathogenesis of CRSwNP. PMID:22534535

  1. Thymomas with prominent glandular differentiation: a clinicopathologic and immunohistochemical study of 12 cases.

    PubMed

    Weissferdt, Annikka; Moran, Cesar A

    2013-08-01

    Twelve cases of thymomas with prominent glandular differentiation are presented. The patients were 7 men and 5 women aged between 45 and 68 years (average, 56.5 years). Clinically, the patients presented with nonspecific symptoms of chest pain, cough, and fatigue. None of the patients had a history of myasthenia gravis or other autoimmune syndrome. Thymectomy was performed in all patients. The tumor size ranged from 4 to 7 cm in greatest diameter. Macroscopically, the tumors were described as firm and light tan without areas of necrosis, hemorrhage, or cystic change. Histologically, 7 tumors were classified as spindle cell (World Health Organization type A), 2 as mixed spindle cell and conventional (A+B1), 2 as conventional (B1), and 1 as atypical thymoma (B3). In 4 cases, the tumors showed invasion into periadipose thymic tissue. All cases showed the typical growth patterns of their particular subtypes. In addition, a distinct glandular component was present in all cases showing mucinous differentiation in 4 of them. Immunohistochemical studies showed tumor cells positive for CAM5.2, cytokeratin 5/6, and Pax8 and negative for carcinoembryonic antigen, thyroid transcription factor 1, and epithelial membrane antigen. Calretinin showed focal weak staining in the nonmucinous glandular components in 3 cases. Follow-up information obtained in 8 patients showed that all were alive and well in a period ranging from 2 to 5 years. The possibility of a glandular component in thymomas should be kept in mind in the assessment of mediastinoscopic biopsies to avoid misdiagnosis for other neoplasms that may require different treatment modalities. PMID:23528863

  2. Mayolenes: labile defensive lipids from the glandular hairs of a caterpillar (Pieris rapae).

    PubMed

    Smedley, Scott R; Schroeder, Frank C; Weibel, Douglas B; Meinwald, Jerrold; Lafleur, Katie A; Renwick, J Alan; Rutowski, Ronald; Eisner, Thomas

    2002-05-14

    Larvae of the European cabbage butterfly, Pieris rapae (Pieridae), are beset with glandular hairs, bearing droplets of a clear oily secretion at their tip. The fluid consists primarily of a series of chemically labile, unsaturated lipids, the mayolenes, which are derived from 11-hydroxylinolenic acid. In bioassays with the ant Crematogaster lineolata, the secretion was shown to be potently deterrent, indicating that the fluid plays a defensive role in nature. PMID:11997469

  3. Examination of equine glandular stomach lesions for bacteria, including Helicobacter spp by fluorescence in situ hybridisation

    PubMed Central

    2010-01-01

    Background The equine glandular stomach is commonly affected by erosion and ulceration. The aim of this study was to assess whether bacteria, including Helicobacter, could be involved in the aetiology of gastric glandular lesions seen in horses. Results Stomach lesions, as well as normal appearing mucosa were obtained from horses slaughtered for human consumption. All samples were tested for urease activity using the Pyloritek® assay, while mucosal bacterial content was evaluated using Fluorescence In Situ Hybridisation. In selected sub samples, bacteria characterisation was pursued further by cloning and sequencing. Mucosal lesions were found in 36/63 stomachs and included hyperplastic rugae, polypoid structures and focal erosions. None of the samples were tested positive for urease activity or for FISH using the Helicobacter genus specific probe. In samples of lesions, as well as normal samples, clones with 99% similarities to Lactobacillus salivarius and Sarcina ventriculi were found. Escherichia like bacterium clones and Enterococcus clones were demonstrated in one focal erosion. Based on a phylogenetic tree these clones had 100% similarity to Escherichia fergusonii and Enterococcus faecium. The Enterococcus were found colonising the mucosal surface, while E. fergusonii organisms were also demonstrated intraepithelial. Conclusion Gastric Helicobacter spp. could not be verified as being involved in lesions of the glandular stomach of the horse. Since E. fergusonii has been described as an emerging pathogen in both humans and animals, the finding of this bacterium in gastric erosion warrants further clarification to whether gastric infection with this type bacterium is important for horses. PMID:20298612

  4. Mixed squamous cell and glandular papilloma of the lung resembling early adenocarcinoma: A case report

    PubMed Central

    Abe, Jiro; Ito, Shigemi; Takahashi, Satomi; Sato, Ikuro; Tanaka, Ryota; Sato, Taku; Okazaki, Toshimasa

    2016-01-01

    Introduction An extremely rare case of mixed squamous cell and glandular papilloma of the lung is reported. The correlation between the radiological and the pathological features as well as the clinical pitfall in making a diagnosis is discussed. Presentation of case An asymptomatic 68-year-old female with a cigarette smoking habit presented with a small nodule in her peripheral lung. A wedge resection was performed though it failed on-site diagnosis which was instead obtained following pathological scrutiny. The postsurgical course was excellent with no recurrence of disease. Discussion A small ground glass nodule gradually enlarged and transformed to a partially solid nodule a year and a half later. This transformation falsely made us suspect an early adenocarcinoma development. Eventually, the extremely rare subtype of pulmonary papilloma, with biphasic glandular and squamous cells, had been demonstrated to obstruct the peripheral bronchiole; and the adjoining alveoli had filled with a large volume of mucus. These pathological features seemed to have constituted the inner solid portion and the marginal ground glass portion respectively in the CT images, mimicking invasive lepidic adenocarcinoma. Conclusion Both pre- and intra-operative diagnoses are difficult mainly because of the rareness of the disease, however, mixed squamous cell and glandular papilloma may be considered in case the presence of primary adenocarcinoma is not validated. PMID:27141302

  5. Effect of the glandular composition on digital breast tomosynthesis image quality and dose optimisation.

    PubMed

    Marques, T; Ribeiro, A; Di Maria, S; Belchior, A; Cardoso, J; Matela, N; Oliveira, N; Janeiro, L; Almeida, P; Vaz, P

    2015-07-01

    In the image quality assessment for digital breast tomosynthesis (DBT), a breast phantom with an average percentage of 50 % glandular tissue is seldom used, which may not be representative of the breast tissue composition of the women undergoing such examination. This work aims at studying the effect of the glandular composition of the breast on the image quality taking into consideration different sizes of lesions. Monte Carlo simulations were performed using the state-of-the-art computer program PENELOPE to validate the image acquisition system of the DBT equipment as well as to calculate the mean glandular dose for each projection image and for different breast compositions. The integrated PENELOPE imaging tool (PenEasy) was used to calculate, in mammography, for each clinical detection task the X-ray energy that maximises the figure of merit. All the 2D cranial-caudal projections for DBT were simulated and then underwent the reconstruction process applying the Simultaneous Algebraic Reconstruction Technique. Finally, through signal-to-noise ratio analysis, the image quality in DBT was assessed. PMID:25836692

  6. Glandular object based tumor morphometry in H&E biopsy samples for prostate cancer prognosis

    NASA Astrophysics Data System (ADS)

    Fogarasi, Stephen I.; Khan, Faisal M.; Pang, Ho-Yuen H.; Mesa-Tejada, Ricardo; Donovan, Michael J.; Fernandez, Gerardo

    2011-03-01

    Morphological and architectural characteristics of primary prostate tissue compartments, such as epithelial nuclei (EN) and cytoplasm, provide critical information for cancer diagnosis, prognosis and therapeutic response prediction. The subjective and variable Gleason grade assessed by expert pathologists in Hematoxylin and Eosin (H&E) stained specimens has been the standard for prostate cancer diagnosis and prognosis. We propose a novel morphometric, glandular object-oriented image analysis approach for the robust quantification of H&E prostate biopsy images. We demonstrate the utility of features extracted through the proposed method in predicting disease progression post treatment in a multi-institution cohort of 1027 patients. The biopsy based features were univariately predictive for clinical response post therapy; with concordance indexes (CI) <= 0.4 or >= 0.6. In multivariate analysis, a glandular object feature quantifying tumor epithelial cells not directly associated with an intact tumor gland was selected in a model incorporating preoperative clinical data, protein biomarker and morphological imaging features. The model achieved a CI of 0.73 in validation, which was significantly higher than a CI of 0.69 for the standard multivariate model based solely on clinical features currently used in clinical practice. This work presents one of the first demonstrations of glandular object based morphological features in the H&E stained biopsy specimen to predict disease progression post primary treatment. Additionally, it is the largest scale study of the efficacy and robustness of the proposed features in prostate cancer prognosis.

  7. Collision-based mechanics of bipedal hopping.

    PubMed

    Gutmann, Anne K; Lee, David V; McGowan, Craig P

    2013-08-23

    The muscle work required to sustain steady-speed locomotion depends largely upon the mechanical energy needed to redirect the centre of mass and the degree to which this energy can be stored and returned elastically. Previous studies have found that large bipedal hoppers can elastically store and return a large fraction of the energy required to hop, whereas small bipedal hoppers can only elastically store and return a relatively small fraction. Here, we consider the extent to which large and small bipedal hoppers (tammar wallabies, approx. 7 kg, and desert kangaroo rats, approx. 0.1 kg) reduce the mechanical energy needed to redirect the centre of mass by reducing collisions. We hypothesize that kangaroo rats will reduce collisions to a greater extent than wallabies since kangaroo rats cannot elastically store and return as high a fraction of the mechanical energy of hopping as wallabies. We find that kangaroo rats use a significantly smaller collision angle than wallabies by employing ground reaction force vectors that are more vertical and center of mass velocity vectors that are more horizontal and thereby reduce their mechanical cost of transport. A collision-based approach paired with tendon morphometry may reveal this effect more generally among bipedal runners and quadrupedal trotters. PMID:23843217

  8. Chicano Hip-Hop as Interethnic Contact Zone

    ERIC Educational Resources Information Center

    McFarland, Pancho

    2008-01-01

    The critical study of rap music and hip-hop culture has the potential to expand Americans understanding of race and culture in the United States. Hip-hop culture as a multiracial, multiethnic phenomenon reveals the ways in which race relations over the past thirty years have become increasingly complex. The theories and concepts that they use to…

  9. Hip-Hop, the "Obama Effect," and Urban Science Education

    ERIC Educational Resources Information Center

    Emdin, Christopher; Lee, Okhee

    2012-01-01

    Background/Context: With the ever increasing diversity of schools, and the persistent need to develop teaching strategies for the students who attend today's urban schools, hip-hop culture has been proposed to be a means through which urban youth can find success in school. As a result, studies of the role of hip-hop in urban education have grown…

  10. Hip Hop as Empowerment: Voices in El Alto, Bolivia

    ERIC Educational Resources Information Center

    Tarifa, Ariana

    2012-01-01

    In response to neoliberal policies that have been in place since 1985, Bolivian young people have increasingly used hip hop music as a means of protest and to reclaim social and political participation. Hip hop in Latin America tells the story of the struggles that marginalized people have suffered, and speaks to the effects of international…

  11. Towards a Pedagogy of Hip Hop in Urban Teacher Education

    ERIC Educational Resources Information Center

    Bridges, Thurman

    2011-01-01

    This article draws from a qualitative study often Black male K-12 teachers from the Hip Hop Generation who are closely connected to Hip Hop culture and have been effective in addressing the academic and social needs of Black boys. Through an analysis of their social, educational and cultural experiences, this article highlights three organizing…

  12. Hip Hop Is Now: An Evolving Youth Culture

    ERIC Educational Resources Information Center

    Taylor, Carl; Taylor, Virgil

    2007-01-01

    Emerging from Rap music, Hip Hop has become a lifestyle to many modern youth around the world. Embodying both creativity and controversy, Hip Hop mirrors the values, violence, and hypocrisy of modern culture. The authors dispel some of the simplistic views that surround this evolving youth movement embraced by millions of young people who are…

  13. Framing and Reviewing Hip-Hop Educational Research

    ERIC Educational Resources Information Center

    Petchauer, Emery

    2009-01-01

    Hip-hop has become relevant to the field of education because of its implications for understanding language, learning, identity, curriculum, and other areas. This integrative review provides historical context and cohesion for the burgeoning and discursive body of hip-hop scholarship by framing it according to three heuristic categories and…

  14. Christian Hip Hop as Pedagogy: A South African Case Study

    ERIC Educational Resources Information Center

    Abraham, Ibrahim

    2015-01-01

    Drawing on interviews with creators of Christian hip hop music in South Africa, this article demonstrates that this genre of popular music and youth culture is utilised as a form of pedagogy to transmit religious beliefs and values to contemporary youth. The pedagogical aspects of hip hop have been recognised in research on the topic, but the…

  15. Toward Hip-Hop Pedagogies for Music Education

    ERIC Educational Resources Information Center

    Kruse, Adam J.

    2016-01-01

    Music education scholarship in the areas of popular, vernacular, and participatory musicianship has grown in the past decades; however, music education research concerned specifically with hip-hop has been relatively scarce. Because hip-hop music can differ tremendously from the traditional western genres with which many music educators are most…

  16. Hop powdery mildew control through alteration of spring pruning practices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since 1997, Podosphaera macularis, the causal agent of hop powdery mildew, has become a recurrent threat to hops in the Pacific Northwest because of the potential to reduce cone yield and quality. Disease management practices often involve preventative fungicide applications, but alternative approac...

  17. Framing Hip Hop: New Methodologies for New Times

    ERIC Educational Resources Information Center

    Dimitriadis, Greg

    2015-01-01

    This article revisits the central impulse behind early advocacy for ethnographic approaches to hip hop--that critics should try as much as possible to limit their own certainties around what hip hop can and might mean. While ethnographic approaches can engender the kinds of personal dislocations that allow for this negotiation, they do not…

  18. Optimum Detection Of Slow-Frequency-Hopping Signals

    NASA Technical Reports Server (NTRS)

    Levitt, Barry K.; Cheng, Unjeng

    1994-01-01

    Two papers present theoretical analyses of various schemes for coherent and noncoherent detection of M-ary-frequency-shift-keyed (MFSK) signals with slow frequency hopping. Special attention focused on continuous-phase-modulation (CPM) subset of SFH/MFSK signals, for which frequency modulation such carrier phase remains continuous (albeit unknown) during each hop.

  19. HD-Zip Proteins GL2 and HDG11 Have Redundant Functions in Arabidopsis Trichomes, and GL2 Activates a Positive Feedback Loop via MYB23[W

    PubMed Central

    Khosla, Aashima; Paper, Janet M.; Boehler, Allison P.; Bradley, Amanda M.; Neumann, Titus R.; Schrick, Kathrin

    2014-01-01

    The class IV homeodomain leucine zipper transcription factor GLABRA2 (GL2) acts in a complex regulatory circuit that regulates the differentiation of trichomes in Arabidopsis thaliana. We describe a genetic interaction with HOMEODOMAIN GLABROUS11 (HDG11), previously identified as a negative regulator of trichome branching. gl2 hdg11 double mutants display enhanced trichome cell-type differentiation defects. Transgenic expression of HDG11 using the GL2 promoter partially suppresses gl2 trichome phenotypes. Vice versa, expression of GL2 under the control of its native promoter partially complements hdg11 ectopic branching. Since gl2 hdg11 and gl2 myb23 double mutants and the triple mutant display similar trichome differentiation defects, we investigated a connection to the R2R3-MYB transcription factor MYB23. We show that MYB23 transcript levels are significantly reduced in shoots from gl2 mutants and that GL2 can drive the expression of a MYB23-promoter fusion to green fluorescent protein. Yeast one-hybrid, chromatin immunoprecipitation, and in planta reporter gene experiments indicate that an L1-box in the MYB23 promoter acts as a GL2 binding site. Taken together, our findings reveal a functional redundancy between GL2 and HDG11, two homeodomain leucine zipper transcription factors previously thought to mediate opposing functions in trichome morphogenesis. A model is proposed in which GL2 transcript levels are maintained through a positive feedback loop involving GL2 activation of MYB23. PMID:24824485

  20. Homeobox Protein Hop Functions in the Adult Cardiac Conduction System

    PubMed Central

    Ismat, Fraz A.; Zhang, Maozhen; Kook, Hyun; Huang, Bin; Zhou, Rong; Ferrari, Victor A.; Epstein, Jonathan A.; Patel, Vickas V.

    2006-01-01

    Hop is an unusual homeobox gene expressed in the embryonic and adult heart. Hop acts downstream of Nkx2–5 during development, and Nkx2–5 mutations are associated with cardiac conduction system (CCS) defects. Inactivation of Hop in the mouse is lethal in half of the expected null embryos. Here, we show that Hop is expressed strongly in the adult CCS. Hop−/− adult mice display conduction defects below the atrioventricular node (AVN) as determined by invasive electrophysiological testing. These defects are associated with decreased expression of connexin40. Our results suggest that Hop functions in the adult CCS and demonstrate conservation of molecular hierarchies between embryonic myocardium and the specialized conduction tissue of the mature heart. PMID:15790958

  1. Trichomes of tobacco excrete zinc as zinc-substituted calcium carbonate and other zinc-containing compounds.

    PubMed

    Sarret, Géraldine; Harada, Emiko; Choi, Yong-Eui; Isaure, Marie-Pierre; Geoffroy, Nicolas; Fakra, Sirine; Marcus, Matthew A; Birschwilks, Mandy; Clemens, Stephan; Manceau, Alain

    2006-07-01

    Tobacco (Nicotiana tabacum L. cv Xanthi) plants were exposed to toxic levels of zinc (Zn). Zn exposure resulted in toxicity signs in plants, and these damages were partly reduced by a calcium (Ca) supplement. Confocal imaging of intracellular Zn using Zinquin showed that Zn was preferentially accumulated in trichomes. Exposure to Zn and Zn + Ca increased the trichome density and induced the production of Ca/Zn mineral grains on the head cells of trichomes. These grains were aggregates of submicrometer-sized crystals and poorly crystalline material and contained Ca as major element, along with subordinate amounts of Zn, manganese, potassium, chlorine, phosphorus, silicon, and magnesium. Micro x-ray diffraction revealed that the large majority of the grains were composed essentially of metal-substituted calcite (CaCO3). CaCO3 polymorphs (aragonite and vaterite) and CaC2O4 (Ca oxalate) mono- and dihydrate also were identified, either as an admixture to calcite or in separate grains. Some grains did not diffract, although they contained Ca, suggesting the presence of amorphous form of Ca. The presence of Zn-substituted calcite was confirmed by Zn K-edge micro-extended x-ray absorption fine structure spectroscopy. Zn bound to organic compounds and Zn-containing silica and phosphate were also identified by this technique. The proportion of Zn-substituted calcite relative to the other species increased with Ca exposure. The production of Zn-containing biogenic calcite and other Zn compounds through the trichomes is a novel mechanism involved in Zn detoxification. This study illustrates the potential of laterally resolved x-ray synchrotron radiation techniques to study biomineralization and metal homeostasis processes in plants. PMID:16731580

  2. Hip Hop Culture's OGs: A Narrative Inquiry into the Intersection of Hip Hop Culture, Black Males and Their Schooling Experiences

    ERIC Educational Resources Information Center

    Buchanan, Ian P.

    2013-01-01

    Using a critical race lens, this narrative study employs a focus group design to explore the intersections between black males, hip hop culture and schooling experiences. To provide a sociocultural grounding, this study first reviews the research literature around hip hop culture.s sociocultural development and its impact as a culture force that…

  3. Hip-Hop Is My Passport! Using Hip-Hop and Digital Literacies to Understand Global Citizenship Education

    ERIC Educational Resources Information Center

    Horton, Akesha Monique

    2013-01-01

    Hip-hop has exploded around the world among youth. It is not simply an American source of entertainment; it is a global cultural movement that provides a voice for youth worldwide who have not been able to express their "cultural world" through mainstream media. The emerging field of critical hip-hop pedagogy has produced little…

  4. RNA-seq discovery, functional characterization, and comparison of sesquiterpene synthases from Solanum lycopersicum and Solanum habrochaites trichomes.

    PubMed

    Bleeker, Petra M; Spyropoulou, Eleni A; Diergaarde, Paul J; Volpin, Hanne; De Both, Michiel T J; Zerbe, Philipp; Bohlmann, Joerg; Falara, Vasiliki; Matsuba, Yuki; Pichersky, Eran; Haring, Michel A; Schuurink, Robert C

    2011-11-01

    Solanum lycopersicum and Solanum habrochaites (f. typicum) accession PI127826 emit a variety of sesquiterpenes. To identify terpene synthases involved in the production of these volatile sesquiterpenes, we used massive parallel pyrosequencing (RNA-seq) to obtain the transcriptome of the stem trichomes from these plants. This approach resulted initially in the discovery of six sesquiterpene synthase cDNAs from S. lycopersicum and five from S. habrochaites. Searches of other databases and the S. lycopersicum genome resulted in the discovery of two additional sesquiterpene synthases expressed in trichomes. The sesquiterpene synthases from S. lycopersicum and S. habrochaites have high levels of protein identity. Several of them appeared to encode for non-functional proteins. Functional recombinant proteins produced germacrenes, β-caryophyllene/α-humulene, viridiflorene and valencene from (E,E)-farnesyl diphosphate. However, the activities of these enzymes do not completely explain the differences in sesquiterpene production between the two tomato plants. RT-qPCR confirmed high levels of expression of most of the S. lycopersicum sesquiterpene synthases in stem trichomes. In addition, one sesquiterpene synthase was induced by jasmonic acid, while another appeared to be slightly repressed by the treatment. Our data provide a foundation to study the evolution of terpene synthases in cultivated and wild tomato. PMID:21818683

  5. Communication devices for network-hopping communications and methods of network-hopping communications

    DOEpatents

    Buttles, John W.

    2011-12-20

    Wireless communication devices include a software-defined radio coupled to processing circuitry. The processing circuitry is configured to execute computer programming code. Storage media is coupled to the processing circuitry and includes computer programming code configured to cause the processing circuitry to configure and reconfigure the software-defined radio to operate on each of a plurality of communication networks according to a selected sequence. Methods for communicating with a wireless device and methods of wireless network-hopping are also disclosed.

  6. Communication devices for network-hopping communications and methods of network-hopping communications

    DOEpatents

    Buttles, John W

    2013-04-23

    Wireless communication devices include a software-defined radio coupled to processing circuitry. The system controller is configured to execute computer programming code. Storage media is coupled to the system controller and includes computer programming code configured to cause the system controller to configure and reconfigure the software-defined radio to operate on each of a plurality of communication networks according to a selected sequence. Methods for communicating with a wireless device and methods of wireless network-hopping are also disclosed.

  7. Anomalous hopping exponents of ultrathin metal films

    NASA Astrophysics Data System (ADS)

    Phillips, J. C.

    2001-07-01

    Under the above title Markovic et al. [Phys. Rev. B 62, 2195 (2000)] summarized their and others' low-temperature data that show that a consistent underlying conduction mechanism is needed to explain thermally activated resistivities, with an exponent x=0.75(5), on films of Ag, Bi, Pb, and Pd, with thicknesses of 5-15 Å. While this x cannot be explained by any kind of conventional continuum hopping model, with or without Coulomb interactions, here it is shown that the exponent x=34 is the direct result of a filamentary vibron quantum percolation model appropriate to a granular network film. The concepts used in this model were recently used to derive finite-size scaling exponents and/or phase diagrams in many other contexts, including network glasses, the impurity band metal-insulator transition, high-temperature superconductors, and evolutionary biology.

  8. Grand and Semigrand Canonical Basin-Hopping

    PubMed Central

    2015-01-01

    We introduce grand and semigrand canonical global optimization approaches using basin-hopping with an acceptance criterion based on the local contribution of each potential energy minimum to the (semi)grand potential. The method is tested using local harmonic vibrational densities of states for atomic clusters as a function of temperature and chemical potential. The predicted global minima switch from dissociated states to clusters for larger values of the chemical potential and lower temperatures, in agreement with the predictions of a model fitted to heat capacity data for selected clusters. Semigrand canonical optimization allows us to identify particularly stable compositions in multicomponent nanoalloys as a function of increasing temperature, whereas the grand canonical potential can produce a useful survey of favorable structures as a byproduct of the global optimization search. PMID:26669731

  9. Isoxanthohumol--Biologically active hop flavonoid.

    PubMed

    Żołnierczyk, Anna Katarzyna; Mączka, Wanda Krystyna; Grabarczyk, Małgorzata; Wińska, Katarzyna; Woźniak, Edyta; Anioł, Mirosław

    2015-06-01

    Isoxanthohumol (IXN), apart from xanthohumol (XN) and 8-prenylnaringenin (8PN), is one of the most important prenylflavonoids found in hops. Another natural source of this compound is a shrub Sophora flavescens, used in traditional Chinese medicine. Main dietary source of IXN is beer, and the compound is produced from XN during wort boiling. In the human body, the compound is O-demethylated to 8PN, the strongest known phytoestrogen. This process takes place in the liver and in the intestine, where it is mediated by local microflora. It has been reported in some studies that even though beer contains small amounts of hops and its preparations, these compounds may affect the functioning of the human body. IXN exhibits an antiproliferative activity against human cell lines typical for breast cancer (MCF-7), ovarian cancer (A-2780), prostate cancer (DU145 and PC-3), and colon cancer (HT-29 and SW620) cells. It strongly inhibits the activation of the following carcinogens: 2-amino-3-methylimidazol-[4,5-f]quinoline and aflatoxin B1 (AFB1) via human cytochrome P450 (CYP1A2). It also inhibits the production of prostate specific antigen (PSA). IXN significantly reduces the expression of transforming growth factor-β (TGF-β) in the case of invasive breast cancer MDA-MB-231. It interferes with JAK/STAT signaling pathway and inhibits the expression of pro1inflammatory genes in the monoblastic leukemia cell line (MonoMac6). It activates apoptosis in human umbilical vein endothelial cells (HUVEC) and human aortic smooth muscle cells (HASMCs). In addition, IXN shows an antiviral activity towards herpes viruses (HSV1 and HSV2) and bovine viral diarrhea virus (BVDV). PMID:25771121

  10. Power-Hop: A Pervasive Observation for Real Complex Networks

    PubMed Central

    Papalexakis, Evangelos; Hooi, Bryan; Pelechrinis, Konstantinos; Faloutsos, Christos

    2016-01-01

    Complex networks have been shown to exhibit universal properties, with one of the most consistent patterns being the scale-free degree distribution, but are there regularities obeyed by the r-hop neighborhood in real networks? We answer this question by identifying another power-law pattern that describes the relationship between the fractions of node pairs C(r) within r hops and the hop count r. This scale-free distribution is pervasive and describes a large variety of networks, ranging from social and urban to technological and biological networks. In particular, inspired by the definition of the fractal correlation dimension D2 on a point-set, we consider the hop-count r to be the underlying distance metric between two vertices of the network, and we examine the scaling of C(r) with r. We find that this relationship follows a power-law in real networks within the range 2 ≤ r ≤ d, where d is the effective diameter of the network, that is, the 90-th percentile distance. We term this relationship as power-hop and the corresponding power-law exponent as power-hop exponent h. We provide theoretical justification for this pattern under successful existing network models, while we analyze a large set of real and synthetic network datasets and we show the pervasiveness of the power-hop. PMID:26974560

  11. Particle hopping vs. fluid-dynamical models for traffic flow

    SciTech Connect

    Nagel, K.

    1995-12-31

    Although particle hopping models have been introduced into traffic science in the 19509, their systematic use has only started recently. Two reasons for this are, that they are advantageous on modem computers, and that recent theoretical developments allow analytical understanding of their properties and therefore more confidence for their use. In principle, particle hopping models fit between microscopic models for driving and fluiddynamical models for traffic flow. In this sense, they also help closing the conceptual gap between these two. This paper shows connections between particle hopping models and traffic flow theory. It shows that the hydrodynamical limits of certain particle hopping models correspond to the Lighthill-Whitham theory for traffic flow, and that only slightly more complex particle hopping models produce already the correct traffic jam dynamics, consistent with recent fluid-dynamical models for traffic flow. By doing so, this paper establishes that, on the macroscopic level, particle hopping models are at least as good as fluid-dynamical models. Yet, particle hopping models have at least two advantages over fluid-dynamical models: they straightforwardly allow microscopic simulations, and they include stochasticity.

  12. Scaffold hopping in drug discovery using inductive logic programming.

    PubMed

    Tsunoyama, Kazuhisa; Amini, Ata; Sternberg, Michael J E; Muggleton, Stephen H

    2008-05-01

    In chemoinformatics, searching for compounds which are structurally diverse and share a biological activity is called scaffold hopping. Scaffold hopping is important since it can be used to obtain alternative structures when the compound under development has unexpected side-effects. Pharmaceutical companies use scaffold hopping when they wish to circumvent prior patents for targets of interest. We propose a new method for scaffold hopping using inductive logic programming (ILP). ILP uses the observed spatial relationships between pharmacophore types in pretested active and inactive compounds and learns human-readable rules describing the diverse structures of active compounds. The ILP-based scaffold hopping method is compared to two previous algorithms (chemically advanced template search, CATS, and CATS3D) on 10 data sets with diverse scaffolds. The comparison shows that the ILP-based method is significantly better than random selection while the other two algorithms are not. In addition, the ILP-based method retrieves new active scaffolds which were not found by CATS and CATS3D. The results show that the ILP-based method is at least as good as the other methods in this study. ILP produces human-readable rules, which makes it possible to identify the three-dimensional features that lead to scaffold hopping. A minor variant of a rule learnt by ILP for scaffold hopping was subsequently found to cover an inhibitor identified by an independent study. This provides a successful result in a blind trial of the effectiveness of ILP to generate rules for scaffold hopping. We conclude that ILP provides a valuable new approach for scaffold hopping. PMID:18457387

  13. Biotransformation of hop aroma terpenoids by ale and lager yeasts.

    PubMed

    King, Andrew J; Dickinson, J Richard

    2003-03-01

    Terpenoids are important natural flavour compounds, which are introduced to beer via hopping. It has been shown recently that yeasts are able to biotransform some monoterpene alcohols. As a first step towards examining whether yeasts are capable of altering hop terpenoids during the brewing of beer, we investigated whether they were transformed when an ale and lager yeast were cultured in the presence of a commercially available syrup. Both yeasts transformed the monoterpene alcohols geraniol and linalool. The lager yeast also produced acetate esters of geraniol and citronellol. The major terpenoids of hop oil, however, were not biotransformed. Oxygenated terpenoids persisted much longer than the alkenes. PMID:12702246

  14. [Cytophysiology of the glandular lobe of the corpora cardiaca: ergastoplasmic granules and their significance].

    PubMed

    Lafon-Cazal, M; Michel, R

    1977-01-01

    The number of ergastoplasmic granules in the glandular lobe of the corpora cardiaca is counted in Locusta migratoria migratorioides R. and F. and Schistocerca gregaria Forsk., male adults of different ages, grouped or isolated, having flown or not, and reared in various conditions of hygrometry and temperature. A good correlation was found between the number of ergastoplasmic granules and the utilization of the adipokinetic hormone. Ergastoplasmic granules may représent an original mechanism of hormonal storage used in view of heavy metabolic requirements. PMID:615543

  15. Let Me Blow Your Mind: Hip Hop Feminist Futures in Theory and Praxis

    ERIC Educational Resources Information Center

    Lindsey, Treva B.

    2015-01-01

    This essay brings together key theoretical interventions in hip-hop feminism to explore the continued, but undervalued, significance of hip-hop feminism in urban education. More specifically, the essay challenges narrow conceptualizations of the "hip hop subject" as Black and male by using hip-hop feminist theory to incorporate the lived…

  16. 60. View of lined canal and hop barn, looking southwest. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    60. View of lined canal and hop barn, looking southwest. Photo by Robin Lee Tedder, Puget Power, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  17. 59. View of lined canal east of bellmouth near hop ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    59. View of lined canal east of bellmouth near hop barn, looking southwest. Photo by Robin Lee Tedder, Puget Power, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  18. GENERAL VIEW OF SITE LOOKING SOUTHWEST. JUPITER 'HOP' STAND, FOREGROUND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    GENERAL VIEW OF SITE LOOKING SOUTHWEST. JUPITER 'HOP' STAND, FOREGROUND CENTER, REDSTONE TEST STAND FOREGROUND RIGHT, SATURN I C TEST STAND BACKGROUND LEFT. - Marshall Space Flight Center, Redstone Rocket (Missile) Test Stand, Dodd Road, Huntsville, Madison County, AL

  19. Fate of xanthohumol and related prenylflavonoids from hops to beer.

    PubMed

    Stevens, J F; Taylor, A W; Clawson, J E; Deinzer, M L

    1999-06-01

    The fate of three prenylated flavonoids of the chalcone type, xanthohumol, desmethylxanthohumol, and 3'-geranylchalconaringenin, was monitored with LC/MS-MS from hops (Humulus lupulus L.) to beer in two brewing trials. The three prenylchalcones were largely converted into their isomeric flavanones, isoxanthohumol, prenylnaringenins, and geranylnaringenins, respectively, in the boiling wort. Losses of prenylflavonoids were due to incomplete extraction from the hops into the wort (13-25%), adsorption to insoluble malt proteins (18-26%), and adsorption to yeast cells (11-32%) during fermentation. The overall yield of xanthohumol, after lagering of the beer and largely in the form of isoxanthohumol, amounted to 22-30% of the hops' xanthohumol. About 10% of the hops' desmethylxanthohumol, completely converted into prenylnaringenins, remained in the beers. 3'-Geranylchalconaringenin behaved similarly to desmethylxanthohumol. Solubility experiments indicated that (1) malt carbohydrates form soluble complexes with xanthohumol and isoxanthohumol and (2) solubility does not dictate the isoxanthohumol levels of finished beers. PMID:10794646

  20. Understanding the Surface Hopping View of Electronic Transitions and Decoherence

    NASA Astrophysics Data System (ADS)

    Subotnik, Joseph E.; Jain, Amber; Landry, Brian; Petit, Andrew; Ouyang, Wenjun; Bellonzi, Nicole

    2016-05-01

    We present a current, up-to-date review of the surface hopping methodology for solving nonadiabatic problems, 25 years after Tully published the fewest switches surface hopping algorithm. After reviewing the original motivation for and failures of the algorithm, we give a detailed examination of modern advances, focusing on both theoretical and practical issues. We highlight how one can partially derive surface hopping from the Schrödinger equation in the adiabatic basis, how one can change basis within the surface hopping algorithm, and how one should understand and apply the notions of decoherence and wavepacket bifurcation. The question of time reversibility and detailed balance is also examined at length. Recent applications to photoexcited conjugated polymers are discussed briefly.

  1. Correlated barrier hopping of CuO nanoparticles

    NASA Astrophysics Data System (ADS)

    Koshy, Jiji; Soosen, Samuel. M.; Chandran, Anoop; George, K. C.

    2015-12-01

    The ac conduction mechanism in copper oxide nanoparticles with 8 nm size, synthesized by a precipitation method was studied by analyzing ac conductivity in the frequency range of 50 Hz-1 MHz and in the temperature range of 373-573 K. X-ray diffraction and transmission electron microscopy (TEM) were employed for the structural and morphological characterization of CuO nanoparticles. The experimental and theoretical investigations suggested that the ac conduction mechanism in CuO nanoparticles can be successfully explained by a correlated barrier hopping model, which provided reasonable values for the maximum barrier height and characteristic relaxation time. It was also found that bipolaron hopping become prominent up to a particular temperature and beyond that single polaron hopping predominates. Physical parameters such as hopping distance and density of defect states were also calculated. Photoluminescence studies confirm the presence of a surface defect in CuO nanoparticles.

  2. Spin-memory effect and negative magnetoresistance in hopping conductivity

    NASA Astrophysics Data System (ADS)

    Agam, Oded; Aleiner, Igor L.; Spivak, Boris

    2014-03-01

    We propose a mechanism for negative isotropic magnetoresistance in the hopping regime. It results from a memory effect encrypted into spin correlations that are not taken into account by the conventional theory of hopping conductivity. The spin correlations are generated by the nonequilibrium electric currents and lead to the decrease of the conductivity. The application of the magnetic field destroys the correlations thus enhancing the conductance. This effect can occur even at magnetic fields as small as a few gauss.

  3. Proton hopping: a proposed mechanism for myelinated axon nerve impulses.

    PubMed

    Kier, Lemont B; Tombes, Robert M

    2013-04-01

    Myelinated axon nerve impulses travel 100 times more rapidly than impulses in non-myelinated axons. Increased speed is currently believed to be due to 'hopping' or 'saltatory propagation' along the axon, but the mechanism by which impulses flow has never been adequately explained. We have used modeling approaches to simulate a role for proton hopping in the space between the plasma membrane and myelin sheath as the mechanism of nerve action-potential flow. PMID:23576345

  4. Toad Glandular Secretions and Skin Extractions as Anti-Inflammatory and Anticancer Agents

    PubMed Central

    Tan, C. K.; Hashimi, Saeed M.; Zulfiker, Abu Hasanat Md.; Wei, Ming Q.

    2014-01-01

    Toad glandular secretions and skin extractions contain many natural agents which may provide a unique resource for novel drug development. The dried secretion from the auricular and skin glands of Chinese toad (Bufo bufo gargarizans) is named Chansu, which has been used in Traditional Chinese Medicine (TCM) for treating infection and inflammation for hundreds of years. The sterilized hot water extraction of dried toad skin is named Huachansu (Cinobufacini) which was developed for treating hepatitis B virus (HBV) and several types of cancers. However, the mechanisms of action of Chansu, Huachansu, and their constituents within are not well reported. Existing studies have suggested that their anti-inflammation and anticancer potential were via targeting Nuclear Factor (NF)-κB and its signalling pathways which are crucial hallmarks of inflammation and cancer in various experimental models. Here, we review some current studies of Chansu, Huachansu, and their compounds in terms of their use as both anti-inflammatory and anticancer agents. We also explored the potential use of toad glandular secretions and skin extractions as alternate resources for treating human cancers in combinational therapies. PMID:24734105

  5. Glandular differentiation in dedifferentiated chondrosarcoma: molecular evidence of a rare phenomenon.

    PubMed

    Jour, George; Liu, Yajuan; Ricciotti, Robert; Pritchard, Colin; Hoch, Benjamin L

    2015-09-01

    Epithelial glandular differentiation in dedifferentiated chondrosarcoma has not been described. Our patient was a 64-year-old man with a history of prostate cancer status post-radiation and hormonal therapy. On screening bone scan, he was found to have increased uptake in his right femoral shaft. Biopsy revealed intermediate-grade conventional chondrosarcoma. Subsequent femoral resection was remarkable for an intermediate-grade chondrosarcomatous component juxtaposed to an area composed of anastomosing nests and cords of malignant epithelial cells showing nuclear atypia and increased mitotic activity. A fibroblastic-appearing spindle cell population was intimately associated with the epithelial cells. The epithelial cells labeled with 34bE12, AE1/AE3, EMA, and Vimentin (both spindled and epithelial components) while being negative for prostate-specific antigen, prostate specific acid phosphatase, cytokeratin 20, thyroid transcription factor-1, and CDX2. The patient developed local recurrence 9 months after the initial resection but has had no metastatic disease and consistently undetectable prostate-specific antigen levels. Deep parallel sequencing of the dedifferentiated component showed a nonsynonymous mutation at exon 4 of IDH1 gene at codon R132 leading to a substitution of arginine, with serine confirming glandular differentiation in dedifferentiated chondrosarcoma. PMID:26198745

  6. A polynomial hyperelastic model for the mixture of fat and glandular tissue in female breast.

    PubMed

    Calvo-Gallego, Jose L; Martínez-Reina, Javier; Domínguez, Jaime

    2015-09-01

    In the breast of adult women, glandular and fat tissues are intermingled and cannot be clearly distinguished. This work studies if this mixture can be treated as a homogenized tissue. A mechanical model is proposed for the mixture of tissues as a function of the fat content. Different distributions of individual tissues and geometries have been tried to verify the validity of the mixture model. A multiscale modelling approach was applied in a finite element model of a representative volume element (RVE) of tissue, formed by randomly assigning fat or glandular elements to the mesh. Both types of tissues have been assumed as isotropic, quasi-incompressible hyperelastic materials, modelled with a polynomial strain energy function, like the homogenized model. The RVE was subjected to several load cases from which the constants of the polynomial function of the homogenized tissue were fitted in the least squares sense. The results confirm that the fat volume ratio is a key factor in determining the properties of the homogenized tissue, but the spatial distribution of fat is not so important. Finally, a simplified model of a breast was developed to check the validity of the homogenized model in a geometry similar to the actual one. PMID:25950862

  7. Further Studies on Barretts Mucosa in Baboons: Metaplastic Glandular Cells Produce Sialomucin

    PubMed Central

    RUBIO, CARLOS A.; OWSTON, MICHAEL; ORREGO, ABIEL; DICK, EDWARD J.

    2012-01-01

    Background In humans and in baboons, protracted gastro-esophageal reflux (GER) transforms the squamous-lined esophagus into columnar-lined (that is Barrett's mucosa, BM). Alcian blue stain (AB) is used to evidence sialomucin-producing goblet cells in human BM. Aim To assess the frequency and distribution of sialomucin-producing cells in BM in baboons. Materials and Methods Sections from 137 consecutive baboon esophagi were alternatively stained with hematoxylin-eosin (H&E) and with AB (pH 2.5), without counterstain. Results Out of 137 baboons, 131 (95.6%) had BM. Columnar and intramucosal glandular cells produced sialomucin in all 131 of these animals. Many BM cells were ballooned and filled with sialomucins, despite goblet cells not being found in H&E sections. Conclusion In humans, protracted GER is a disease requiring medication that may lead to BM; AB stains mainly goblet cells and occasional columnar cells in BM. In baboons, in contrast, BM is a natural postnatal process of adaptation to GER, triggered by regurgitation and rumination. AB stains all columnar and intra-mucosal glandular cells. Sialomucin-overstuffed cells were more frequent and larger in baboons than in humans. The extra load of sialomucin in BM might be an integrated part of the postnatal life-long process of adaptation to regurgitation and rumination in baboons. PMID:21036729

  8. Gold Binding by Native and Chemically Modified Hops Biomasses

    DOE PAGESBeta

    López, M. Laura; Gardea-Torresdey, J. L.; Peralta-Videa, J. R.; de la Rosa, G.; Armendáriz, V.; Herrera, I.; Troiani, H.; Henning, J.

    2005-01-01

    Heavy metals from mining, smelting operations and other industrial processing facilities pollute wastewaters worldwide. Extraction of metals from industrial effluents has been widely studied due to the economic advantages and the relative ease of technical implementation. Consequently, the search for new and improved methodologies for the recovery of gold has increased. In this particular research, the use of cone hops biomass ( Humulus lupulus ) was investigated as a new option for gold recovery. The results showed that the gold binding to native hops biomass was pH dependent from pH 2 to pH 6, with a maximum percentage bindingmore » at pH 3. Time dependency studies demonstrated that Au(III) binding to native and modified cone hops biomasses was found to be time independent at pH 2 while at pH 5, it was time dependent. Capacity experiments demonstrated that at pH 2, esterified hops biomass bound 33.4 mg Au/g of biomass, while native and hydrolyzed hops biomasses bound 28.2 and 12.0 mg Au/g of biomass, respectively. However, at pH 5 the binding capacities were 38.9, 37.8 and 11.4 mg of Au per gram of native, esterified and hydrolyzed hops biomasses, respectively.« less

  9. Coding for slow frequency hopped differential phase shift keying

    NASA Astrophysics Data System (ADS)

    Wang, Qiang; Gulliver, T. A.; Mason, Lloyd J.; Blake, Ian F.

    The performance of Reed-Solomon (RS) error-correcting codes with slow frequency hopped (SFH) differential phase shift keying (DPSK) signaling is analyzed and evaluated under worst-case partial-band noise (PBN) and worst-case multitone (MT) jamming. The results of a study of the bit error rate (BER) performance of this coded system are presented. A representative set of the performance curves is shown. SFH is used because the differential signaling required only the phase of the previous received signal as a reference. Using DPSK eliminates the need to establish a phase reference for the hop, as with coherent signaling. From the results it is clear that the number of codeword symbols per hop must be small in order for the RS code to provide protection against jamming. Otherwise, no improvement over uncoded DPSK is gained. Lowering the symbols per hop can be achieved either by reducing the number of bits per hop, or interleaving the RS codewords to a depth determined by the hop length and RS code parameters.

  10. Extreme Kinematics in Selected Hip Hop Dance Sequences.

    PubMed

    Bronner, Shaw; Ojofeitimi, Sheyi; Woo, Helen

    2015-09-01

    Hip hop dance has many styles including breakdance (breaking), house, popping and locking, funk, streetdance, krumping, Memphis jookin', and voguing. These movements combine the complexity of dance choreography with the challenges of gymnastics and acrobatic movements. Despite high injury rates in hip hop dance, particularly in breakdance, to date there are no published biomechanical studies in this population. The purpose of this study was to compare representative hip hop steps found in breakdance (toprock and breaking) and house and provide descriptive statistics of the angular displacements that occurred in these sequences. Six expert female hip hop dancers performed three choreographed dance sequences, top rock, breaking, and house, to standardized music-based tempos. Hip, knee, and ankle kinematics were collected during sequences that were 18 to 30 sec long. Hip, knee, and ankle three-dimensional peak joint angles were compared in repeated measures ANOVAs with post hoc tests where appropriate (p<0.01). Peak angles of the breaking sequence, which included floorwork, exceeded the other two sequences in the majority of planes and joints. Hip hop maximal joint angles exceeded reported activities of daily living and high injury sports such as gymnastics. Hip hop dancers work at weight-bearing joint end ranges where muscles are at a functional disadvantage. These results may explain why lower extremity injury rates are high in this population. PMID:26395613

  11. Signaling induced by hop/STI-1 depends on endocytosis

    SciTech Connect

    Americo, Tatiana A.; Chiarini, Luciana B.; Linden, Rafael . E-mail: rlinden@biof.ufrj.br

    2007-06-29

    The co-chaperone hop/STI-1 is a ligand of the cell surface prion protein (PrP{sup C}), and their interaction leads to signaling and biological effects. Among these, hop/STI-1 induces proliferation of A172 glioblastoma cells, dependent on both PrP{sup C} and activation of the Erk pathway. We tested whether clathrin-mediated endocytosis affects signaling induced by hop/STI-1. Both hyperosmolarity induced by sucrose and monodansyl-cadaverine blocked Erk activity induced by hop/STI-1, without affecting the high basal Akt activity typical of A172. The endocytosis inhibitors also affected the sub-cellular distribution of phosphorylated Erk, consistent with blockade of the latter's activity. The data indicate that signaling induced by hop/STI-1 depends on endocytosis. These findings are consistent with a role of sub-cellular trafficking in signal transduction following engagement by PrP{sup C} by ligands such as hop/STI-1, and may help help unravel both the functions of the prion protein, as well as possible loss-of-function components of prion diseases.

  12. Accurate water maser positions from HOPS

    NASA Astrophysics Data System (ADS)

    Walsh, Andrew J.; Purcell, Cormac R.; Longmore, Steven N.; Breen, Shari L.; Green, James A.; Harvey-Smith, Lisa; Jordan, Christopher H.; Macpherson, Christopher

    2014-08-01

    We report on high spatial resolution water maser observations, using the Australia Telescope Compact Array, towards water maser sites previously identified in the H2O southern Galactic Plane Survey (HOPS). Of the 540 masers identified in the single-dish observations of Walsh et al., we detect emission in all but 31 fields. We report on 2790 spectral features (maser spots), with brightnesses ranging from 0.06 to 576 Jy and with velocities ranging from -238.5 to +300.5 km s-1. These spectral features are grouped into 631 maser sites. We have compared the positions of these sites to the literature to associate the sites with astrophysical objects. We identify 433 (69 per cent) with star formation, 121 (19 per cent) with evolved stars and 77 (12 per cent) as unknown. We find that maser sites associated with evolved stars tend to have more maser spots and have smaller angular sizes than those associated with star formation. We present evidence that maser sites associated with evolved stars show an increased likelihood of having a velocity range between 15 and 35 km s-1 compared to other maser sites. Of the 31 non-detections, we conclude they were not detected due to intrinsic variability and confirm previous results showing that such variable masers tend to be weaker and have simpler spectra with fewer peaks.

  13. TU-F-18C-05: Evaluation of a Method to Calculate Patient-Oriented MGD Coefficients Using Estimates of Glandular Tissue Distribution

    SciTech Connect

    Porras-Chaverri, M; Galavis, P; Bakic, P; Vetter, J

    2014-06-15

    Purpose: Evaluate mammographic mean glandular dose (MGD) coefficients for particular known tissue distributions using a novel formalism that incorporates the effect of the heterogeneous glandular tissue distribution, by comparing them with MGD coefficients derived from the corresponding anthropomorphic computer breast phantom. Methods: MGD coefficients were obtained using MCNP5 simulations with the currently used homogeneous assumption and the heterogeneously-layered breast (HLB) geometry and compared against those from the computer phantom (ground truth). The tissue distribution for the HLB geometry was estimated using glandularity map image pairs corrected for the presence of non-glandular fibrous tissue. Heterogeneity of tissue distribution was quantified using the glandular tissue distribution index, Idist. The phantom had 5 cm compressed breast thickness (MLO and CC views) and 29% whole breast glandular percentage. Results: Differences as high as 116% were found between the MGD coefficients with the homogeneous breast core assumption and those from the corresponding ground truth. Higher differences were found for cases with more heterogeneous distribution of glandular tissue. The Idist for all cases was in the [−0.8{sup −}+0.3] range. The use of the methods presented in this work results in better agreement with ground truth with an improvement as high as 105 pp. The decrease in difference across all phantom cases was in the [9{sup −}105] pp range, dependent on the distribution of glandular tissue and was larger for the cases with the highest Idist values. Conclusion: Our results suggest that the use of corrected glandularity image pairs, as well as the HLB geometry, improves the estimates of MGD conversion coefficients by accounting for the distribution of glandular tissue within the breast. The accuracy of this approach with respect to ground truth is highly dependent on the particular glandular tissue distribution studied. Predrag Bakic discloses

  14. Trapping hop looper moths, Hypena humuli Harris (Lepidoptera: Erebidae), in hop yards in Washington State with acetic acid and 3-methyl-1-butanol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hop looper moths, Hypena humuli Harris, in commercial hop yards (Humulus lupulus L.) were captured in traps baited with a combination of acetic acid plus 3-methyl-1-butanol (AAMB). The two chemicals were synergistic in attracting hop looper moths; in a comparison of the lure chemicals, most moths we...

  15. Unexpected roles for ancient proteins: flavone 8-hydroxylase in sweet basil trichomes is a Rieske-type, PAO-family oxygenase.

    PubMed

    Berim, Anna; Park, Jeong-Jin; Gang, David R

    2014-11-01

    Most elucidated hydroxylations in plant secondary metabolism are catalyzed by oxoglutarate- or cytochrome P450-dependent oxygenases. Numerous hydroxylations still evade clarification, suggesting that they might be performed by alternative enzyme types. Here, we report the identification of the flavone 8-hydroxylase (F8H) in sweet basil (Ocimum basilicum L.) trichomes as a Rieske-type oxygenase. Several features of the F8H activity in trichome protein extracts helped to differentiate it from a cytochrome P450-catalyzed reaction and identify candidate genes in the basil trichome EST database. The encoded ObF8H proteins share approximately 50% identity with Rieske-type protochlorophyllide a oxygenases (PTC52) from higher plants. Homology cloning and DNA blotting revealed the presence of several PTC52-like genes in the basil genome. The transcripts of the candidate gene designated ObF8H-1 are strongly enriched in trichomes compared to whole young leaves, indicating trichome-specific expression. The full-length ObF8H-1 protein possesses a predicted N-terminal transit peptide, which directs green fluorescent protein at least in part to chloroplasts. The F8H activity in crude trichome protein extracts correlates well with the abundance of ObF8H peptides. The purified recombinant ObF8H-1 displays high affinity for salvigenin and is inactive with other tested flavones except cirsimaritin, which is 8-hydroxylated with less than 0.2% relative activity. The efficiency of in vivo 8-hydroxylation by engineered yeast was improved by manipulation of protein subcellular targeting. blast searches showed that occurrence of several PTC52-like genes is rather common in sequenced plant genomes. The discovery of ObF8H suggests that Rieske-type oxygenases may represent overlooked candidate catalysts for oxygenations in specialized plant metabolism. PMID:25139498

  16. Viability of dried vegetative trichomes, formation of akinetes and heterocysts and akinete germination in some blue-green algae under water stress.

    PubMed

    Agrawal, S C; Singh, V

    1999-01-01

    Almost all dried vegetative trichomes ofAnabaena iyengarii, Westiellopsis prolifica andNostochopsis lobatus died within 1 h, while those ofOscillatoria acuminata retained viability to some extent for 1 d under similar storage conditions. The viability of dried vegetative trichomes ofO. acuminata decreased about equally on storage at 20 degrees C in the light or in the dark, but dropped rapidly at 12 and 0 degrees C in the dark. Vegetative trichomes ofA. iyengarii, N. lobatus andW. prolifica were more sensitive to frost than those ofO. acuminata, and this correlated with their low resistance to desiccation because both types of exposure involved osmotic stress. Both dried and wet akinetes ofA. iyengarii, W. prolifica andN. lobatus were about equally viable when stored at 20 degrees C in the light or the dark or at 12 and 0 degrees C in the dark, but their germination ability decreased on storage at 0 degrees C. The water stress imposed on growing vegetative trichomes either in high-agar media or in NaCl-supplemented liquid media reduced the survival ofO. acuminata trichomes, decreased or totally suppressed akinete and heterocyst formation and akinete germination inA. iyengarii, W. prolifica andN. lobatus. The sensitivity decreased in the sequenceA. iyengarii Trichomes ofO. acuminata became broader when grown in 0.5-0.8 mol/L NaCl-supplemented media, probably due to polyol accumulation, and they also developed a thin sheath-like structure. PMID:18461490

  17. Multi-hop teleportation based on W state and EPR pairs

    NASA Astrophysics Data System (ADS)

    Hai-Tao, Zhan; Xu-Tao, Yu; Pei-Ying, Xiong; Zai-Chen, Zhang

    2016-05-01

    Multi-hop teleportation has significant value due to long-distance delivery of quantum information. Many studies about multi-hop teleportation are based on Bell pairs, partially entangled pairs or W state. The possibility of multi-hop teleportation constituted by partially entangled pairs relates to the number of nodes. The possibility of multi-hop teleportation constituted by double W states is after n-hop teleportation. In this paper, a multi-hop teleportation scheme based on W state and EPR pairs is presented and proved. The successful possibility of quantum information transmitted hop by hop through intermediate nodes is deduced. The possibility of successful transmission is after n-hop teleportation. Project supported by the National Natural Science Foundation of China (Grant No. 61571105), the Prospective Future Network Project of Jiangsu Province, China (Grant No. BY2013095-1-18), and the Independent Project of State Key Laboratory of Millimeter Waves, China (Grant No. Z201504).

  18. From "They" Science to "Our" Science: Hip Hop Epistemology in STEAM Education

    NASA Astrophysics Data System (ADS)

    Dolberry, Maurice E.

    Hip hop has moved from being considered a type of music into being understood as a culture in which a prominent type of music originates. Hip hop culture has a philosophy and epistemological constructs as well. This study analyzed those constructs to determine how conceptions of science factor in hip hop worldviews. Pedagogical models in culturally responsive teaching and Science, Technology, Engineering, Arts, and Mathematics (STEAM) education were also examined to discern their philosophical connections with hip hop culture. These connections were used to create two theoretical models. The first one, Hip Hop Science, described how scientific thought functions in hip hop culture. The second model, Hip Hop STEAM Pedagogy, proposes how hip hop culture can inform STEAM teaching practices. The study began by using Critical Race Theory to create a theoretical framework proposing how the two theoretical models could be derived from the philosophical and pedagogical concepts. Content analysis and narrative inquiry were used to analyze data collected from scholarly texts, hip hop songs, and interviews with hip hop-responsive educators. The data from these sources were used initially to assess the adequacy of the proposed theoretical framework, and subsequently to improve its viability. Four overlapping themes emerged from the data analyses, including hip hop-resistance to formal education; how hip hop culture informs pedagogical practice in hip hop-responsive classrooms; conceptions of knowledge and reality that shape how hip hoppers conduct scientific inquiry; and hip hop-based philosophies of effective teaching for hip hoppers as a marginalized cultural group. The findings indicate that there are unique connections between hip hop epistemology, sciencemindedness, and pedagogical practices in STEAM education. The revised theoretical framework clarified the nature of these connections, and supported claims from prior research that hip hop culture provides viable sites of

  19. Incidence of anti-intermediate filament antibody in serum samples of students with suspected glandular fever.

    PubMed Central

    Kataaha, P K; Holborow, E J; Edwards, J M

    1985-01-01

    Serum samples from 40 students with suspected infectious mononucleosis were tested for the presence of antibodies to intermediate filaments (AIFA) of the cytoskeleton. Twenty had antibodies to the Epstein-Barr virus capsid antigen before their illness, and during it their sera remained negative by the Paul-Bunnell test. The other 20 patients did not have antibodies to the Epstein-Barr virus capsid antigen before their illness and seroconverted during the illness. These patients (true infectious mononucleosis group) developed positive Paul-Bunnell tests. Sera from normal subjects (blood donors) were also tested for AIFA. AIFA was present in titres greater than 1/10 in 80% of the infectious mononucleosis group (mean titre 1/40-1/80), 10% of the Paul-Bunnell negative glandular fever group, and 8.5% of the normal blood donors. PMID:2982922

  20. PTEN Phosphatase-Independent Maintenance of Glandular Morphology in a Predictive Colorectal Cancer Model System1

    PubMed Central

    Jagan, Ishaan C; Deevi, Ravi K; Fatehullah, Aliya; Topley, Rebecca; Eves, Joshua; Stevenson, Michael; Loughrey, Maurice; Arthur, Kenneth; Campbell, Frederick Charles

    2013-01-01

    Organotypic models may provide mechanistic insight into colorectal cancer (CRC) morphology. Three-dimensional (3D) colorectal gland formation is regulated by phosphatase and tensin homologue deleted on chromosome 10 (PTEN) coupling of cell division cycle 42 (cdc42) to atypical protein kinase C (aPKC). This study investigated PTEN phosphatase-dependent and phosphatase-independent morphogenic functions in 3D models and assessed translational relevance in human studies. Isogenic PTEN-expressing or PTEN-deficient 3D colorectal cultures were used. In translational studies, apical aPKC activity readout was assessed against apical membrane (AM) orientation and gland morphology in 3D models and human CRC. We found that catalytically active or inactive PTEN constructs containing an intact C2 domain enhanced cdc42 activity, whereas mutants of the C2 domain calcium binding region 3 membrane-binding loop (M-CBR3) were ineffective. The isolated PTEN C2 domain (C2) accumulated in membrane fractions, but C2 M-CBR3 remained in cytosol. Transfection of C2 but not C2 M-CBR3 rescued defective AM orientation and 3D morphogenesis of PTEN-deficient Caco-2 cultures. The signal intensity of apical phospho-aPKC correlated with that of Na+/H+ exchanger regulatory factor-1 (NHERF-1) in the 3D model. Apical NHERF-1 intensity thus provided readout of apical aPKC activity and associated with glandular morphology in the model system and human colon. Low apical NHERF-1 intensity in CRC associated with disruption of glandular architecture, high cancer grade, and metastatic dissemination. We conclude that the membrane-binding function of the catalytically inert PTEN C2 domain influences cdc42/aPKC-dependent AM dynamics and gland formation in a highly relevant 3D CRC morphogenesis model system. PMID:24348097

  1. Glandular Proteome Identifies Antiprotease Cystatin C as a Critical Modulator of Airway Hydration and Clearance.

    PubMed

    Evans, T Idil Apak; Joo, Nam Soo; Keiser, Nicholas W; Yan, Ziying; Tyler, Scott R; Xie, Weiliang; Zhang, Yulong; Hsiao, Jordy J; Cho, Hyung-Ju; Wright, Michael E; Wine, Jeffrey J; Engelhardt, John F

    2016-04-01

    Defects in the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel lead to viscous secretions from submucosal glands that cannot be properly hydrated and cleared by beating cilia in cystic fibrosis (CF) airways. The mechanisms by which CFTR, and the predominant epithelial sodium channel (ENaC), control the hydration and clearance of glandular secretions remain unclear. We used a proteomics approach to characterize the proteins contained in CF and non-CF submucosal gland fluid droplets and found that differentially regulated proteases (cathepsin S and H) and their antiprotease (cystatin C) influenced the equilibration of fluid on the airway surface and tracheal mucociliary clearance (MCC). Contrary to prevailing models of airway hydration and clearance, cystatin C, or raising the airway surface liquid (ASL) pH, inhibited cathepsin-dependent ENaC-mediated fluid absorption and raised the height of ASL, and yet decreased MCC velocity. Importantly, coupling of both CFTR and ENaC activities were required for effective MCC and for effective ASL height equilibration after volume challenge. Cystatin C-inhibitable cathepsins controlled initial phases of ENaC-mediated fluid absorption, whereas CFTR activity was required to prevent ASL dehydration. Interestingly, CF airway epithelia absorbed fluid more slowly owing to reduced cysteine protease activity in the ASL but became abnormally dehydrated with time. Our findings demonstrate that, after volume challenge, pH-dependent protease-mediated coupling of CFTR and ENaC activities are required for rapid fluid equilibration at the airway surface and for effective MCC. These findings provide new insights into how glandular fluid secretions may be equilibrated at the airway surface and how this process may be impaired in CF. PMID:26334941

  2. Comparison of mammography sensitivity after reduction mammoplasty targeting the glandular and fat tissue

    PubMed Central

    Çakır, Murat; Küçükkartallar, Tevfik; Tekin, Ahmet; Selimoğlu, Nebil; Poyraz, Necdet; Belviranlı, Mehmet Metin; Kartal, Adil

    2015-01-01

    Objective: Mammography may have some limitations in the diagnosis and screening of breast cancer for women who have previously undergone breast reduction surgery. This study aimed to investigate how the structural defects in the breast tissue formed by postoperative changes are reflected on mammography. Material and Methods: The records of patients who had previously undergone breast reduction surgery and who were requested to undergo mammography for breast cancer screening by the general surgery clinic were retrospectively studied. The patients’ ages, surgical procedures, postoperative follow-up periods, amount of removed material, and histopathological and mammographic results were studied. The patients were classified into 3 groups: those older than 40 years who underwent reduction mammoplasty targeting predominantly the glandular tissue (group 1), those younger than 40 years who underwent reduction mammoplasty targeting predominantly the fat tissue (group 2), and those older than 40 years who were diagnosed with breast hypertrophy and were not operated (group 3). Results: The mean follow-up period of the patients was 6 (2–10) years. The mean value of resected tissue was 1120 g (680–2070) in group 1 and 1220 g (720–1980) in group 2. The mean age at the time of surgery was 45 (40–70) years for group 1 and 35 (24–40) years for group 2. All patients in group 1 were classified in Breast Imaging-Reporting and Data System (BI-RADS) category 1–2; 28 patients in group 2 were classified in BI-RADS 1–2, 4 were classified in BI-RADS 3, and 8 were classified in BI-RADS 0. In group 3, 35 patients were classified in BI-RADS 1–2, 4 were classified in BI-RADS 3, and 1 was classified in BI-RADS 0. Conclusion: We believe that breast reduction surgery targeting predominantly the glandular tissue in patients older than 40 years increases mammographic sensitivity. PMID:26170752

  3. Effect of filter on average glandular dose and image quality in digital mammography

    NASA Astrophysics Data System (ADS)

    Songsaeng, C.; Krisanachinda, A.; Theerakul, K.

    2016-03-01

    To determine the average glandular dose and entrance surface air kerma in both phantoms and patients to assess image quality for different target-filters (W/Rh and W/Ag) in digital mammography system. The compressed breast thickness, compression force, average glandular dose, entrance surface air kerma, peak kilovoltage and tube current time were recorded and compared between W/Rh and W/Ag target filter. The CNR and the figure of merit were used to determine the effect of target filter on image quality. The mean AGD of the W/Rh target filter was 1.75 mGy, the mean ESAK was 6.67 mGy, the mean CBT was 54.1 mm, the mean CF was 14 1bs. The mean AGD of W/Ag target filter was 2.7 mGy, the mean ESAK was 12.6 mGy, the mean CBT was 75.5 mm, the mean CF was 15 1bs. In phantom study, the AGD was 1.2 mGy at 4 cm, 3.3 mGy at 6 cm and 3.83 mGy at 7 cm thickness. The FOM was 24.6, CNR was 9.02 at thickness 6 cm. The FOM was 18.4, CNR was 8.6 at thickness 7 cm. The AGD from Digital Mammogram system with W/Rh of thinner CBT was lower than the AGD from W/Ag target filter.

  4. Epigenetic alteration of Wnt pathway antagonists in progressive glandular neoplasia of the lung

    PubMed Central

    Licchesi, Julien D.F.; Westra, William H.; Hooker, Craig M.; Machida, Emi O.; Baylin, Stephen B.; Herman, James G.

    2008-01-01

    Background: Atypical adenomatous hyperplasia (AAH) is now recognized as a precursor lesion from which lung adenocarcinomas arise and thus represents an ideal target for studying the early genetic and epigenetic alterations associated with lung tumorigenesis such as alterations of the Wnt pathway. Methods: We assessed the level of Wnt signaling activity in lung cancer cell lines by determining the level of active β-catenin and determined the level of expression of Wnt antagonists APC, DKK1, DKK3, LKB1, SFRP1, 2, 4, 5, WIF1 and RUNX3 using reverse transcription–polymerase chain reaction. Using multiplex nested methylation-specific polymerase chain reaction, we analyzed promoter region methylation of these genes in resected lung tissue in the histopathologic sequence of glandular neoplasia (normal lung parenchyma, low-grade and high-grade AAH, adenocarcinoma). Results: The majority of non-small cell lung cancer cell lines (11 of 16, 69%) have evidence of active Wnt signaling and silencing of Wnt antagonists correlated with promoter hypermethylation. Promoter region methylation of Wnt antagonists was common in primary lung adenocarcinoma and there was a significant increase in the frequency of methylation for Wnt antagonist genes and the number of genes methylated with each stage of tumorigenesis (test for rend P ≤ 0.01). Additionally, odds ratios for promoter hypermethylation of individual or multiple Wnt antagonist genes and adenocarcinomas were statistically significantly elevated and ranged between 3.64 and 48.17. Conclusion: These results show that gene silencing of Wnt antagonists by promoter hypermethylation occurs during the earliest stages of glandular neoplasia of the lung and accumulates with progression toward malignancy. PMID:18308762

  5. Estimates of Average Glandular Dose with Auto-modes of X-ray Exposures in Digital Breast Tomosynthesis

    PubMed Central

    Kamal, Izdihar; Chelliah, Kanaga K.; Mustafa, Nawal

    2015-01-01

    Objectives: The aim of this research was to examine the average glandular dose (AGD) of radiation among different breast compositions of glandular and adipose tissue with auto-modes of exposure factor selection in digital breast tomosynthesis. Methods: This experimental study was carried out in the National Cancer Society, Kuala Lumpur, Malaysia, between February 2012 and February 2013 using a tomosynthesis digital mammography X-ray machine. The entrance surface air kerma and the half-value layer were determined using a 100H thermoluminescent dosimeter on 50% glandular and 50% adipose tissue (50/50) and 20% glandular and 80% adipose tissue (20/80) commercially available breast phantoms (Computerized Imaging Reference Systems, Inc., Norfolk, Virginia, USA) with auto-time, auto-filter and auto-kilovolt modes. Results: The lowest AGD for the 20/80 phantom with auto-time was 2.28 milliGray (mGy) for two dimension (2D) and 2.48 mGy for three dimensional (3D) images. The lowest AGD for the 50/50 phantom with auto-time was 0.97 mGy for 2D and 1.0 mGy for 3D. Conclusion: The AGD values for both phantoms were lower against a high kilovolt peak and the use of auto-filter mode was more practical for quick acquisition while limiting the probability of operator error. PMID:26052465

  6. Optimizing the anode-filter combination in the sense of image quality and average glandular dose in digital mammography

    NASA Astrophysics Data System (ADS)

    Varjonen, Mari; Strömmer, Pekka

    2008-03-01

    This paper presents the optimized image quality and average glandular dose in digital mammography, and provides recommendations concerning anode-filter combinations in digital mammography, which is based on amorphous selenium (a-Se) detector technology. The full field digital mammography (FFDM) system based on a-Se technology, which is also a platform of tomosynthesis prototype, was used in this study. X-ray tube anode-filter combinations, which we studied, were tungsten (W) - rhodium (Rh) and tungsten (W) - silver (Ag). Anatomically adaptable fully automatic exposure control (AAEC) was used. The average glandular doses (AGD) were calculated using a specific program developed by Planmed, which automates the method described by Dance et al. Image quality was evaluated in two different ways: a subjective image quality evaluation, and contrast and noise analysis. By using W-Rh and W-Ag anode-filter combinations can be achieved a significantly lower average glandular dose compared with molybdenum (Mo) - molybdenum (Mo) or Mo-Rh. The average glandular dose reduction was achieved from 25 % to 60 %. In the future, the evaluation will concentrate to study more filter combinations and the effect of higher kV (>35 kV) values, which seems be useful while optimizing the dose in digital mammography.

  7. Abnormal ion content, hydration and granule expansion of the secretory granules from cystic fibrosis airway glandular cells

    SciTech Connect

    Baconnais, S.; Delavoie, F. |; Zahm, J.M.; Milliot, M.; Castillon, N.; Terryn, C.; Banchet, V.; Michel, J.; Danos, O.; Merten, M.; Chinet, T.; Zierold, K.; Bonnet, N.; Puchelle, E. , E-Mail: edith.puchelle@univ-reims.fr; Balossier, G.

    2005-10-01

    The absence or decreased expression of cystic fibrosis transmembrane conductance regulator (CFTR) induces increased Na{sup +} absorption and hyperabsorption of the airway surface liquid (ASL) resulting in a dehydrated and hyperviscous ASL. Although the implication of abnormal airway submucosal gland function has been suggested, the ion and water content in the Cystic Fibrosis (CF) glandular secretory granules, before exocytosis, is unknown. We analyzed, in non-CF and CF human airway glandular cell lines (MM-39 and KM4, respectively), the ion content in the secretory granules by electron probe X-ray microanalysis and the water content by quantitative dark field imaging on freeze-dried cryosections. We demonstrated that the ion content (Na{sup +}, Mg{sup 2+}, P, S and Cl{sup -}) is significantly higher and the water content significantly lower in secretory granules from the CF cell line compared to the non-CF cell line. Using videomicroscopy, we observed that the secretory granule expansion was deficient in CF glandular cells. Transfection of CF cells with CFTR cDNA or inhibition of non-CF cells with CFTR{sub inh}-172, respectively restored or decreased the water content and granule expansion, in parallel with changes in ion content. We hypothesize that the decreased water and increased ion content in glandular secretory granules may contribute to the dehydration and increased viscosity of the ASL in CF.

  8. Topological Anderson insulator induced by inter-cell hopping disorder

    SciTech Connect

    Lv, Shu-Hui; Song, Juntao Li, Yu-Xian

    2013-11-14

    We have studied in detail the influence of same-orbit and different-orbit hopping disorders in HgTe/CdTe quantum wells. Intriguingly, similar to the behavior of the on-site Anderson disorder, a phase transition from a topologically trivial phase to a topological phase is induced at a proper strength of the same-orbit hopping disorder. For different-orbit hopping disorder, however, the phase transition does not occur. The results have been analytically verified by using effective medium theory. A consistent conclusion can be obtained by comparing phase diagrams, conductance, and conductance fluctuations. In addition, the influence of Rashba spin-orbit interaction (RSOI) on the system has been studied for different types of disorder, and the RSOI shows different influence on topological phase at different disorders. The topological phase induced by same-orbit hopping disorder is more robust against the RSOI than that induced by on-site Anderson disorder. For different-orbit hopping disorder, no matter whether the RSOI is included or not, the phase transition does not occur. The results indicate, whether or not the topological Anderson insulator can be observed depends on a competition between the different types of the disorder as well as the strength of the RSOI in a system.

  9. Surface hopping simulation of vibrational predissociation of methanol dimer

    NASA Astrophysics Data System (ADS)

    Jiang, Ruomu; Sibert, Edwin L.

    2012-06-01

    The mixed quantum-classical surface hopping method is applied to the vibrational predissociation of methanol dimer, and the results are compared to more exact quantum calculations. Utilizing the vibrational SCF basis, the predissociation problem is cast into a curve crossing problem between dissociative and quasibound surfaces with different vibrational character. The varied features of the dissociative surfaces, arising from the large amplitude OH torsion, generate rich predissociation dynamics. The fewest switches surface hopping algorithm of Tully [J. Chem. Phys. 93, 1061 (1990), 10.1063/1.459170] is applied to both diabatic and adiabatic representations. The comparison affords new insight into the criterion for selecting the suitable representation. The adiabatic method's difficulty with low energy trajectories is highlighted. In the normal crossing case, the diabatic calculations yield good results, albeit showing its limitation in situations where tunneling is important. The quadratic scaling of the rates on coupling strength is confirmed. An interesting resonance behavior is identified and is dealt with using a simple decoherence scheme. For low lying dissociative surfaces that do not cross the quasibound surface, the diabatic method tends to overestimate the predissociation rate whereas the adiabatic method is qualitatively correct. Analysis reveals the major culprits involve Rabi-like oscillation, treatment of classically forbidden hops, and overcoherence. Improvements of the surface hopping results are achieved by adopting a few changes to the original surface hopping algorithms.

  10. Efros-Shklovskii variable range hopping conductivity without Coulomb gap

    NASA Astrophysics Data System (ADS)

    Chen, Tianran; Skinner, Brian

    In doped semiconductors and Coulomb glasses, in the limit of weak coupling, the electron conductivity primarily proceeds by phonon-assisted tunneling or hopping between different sites through the insulating gaps that separate them. Electron conduction can occur both through nearest-neighbor hopping and through cotunneling of electrons between distant sites via a chain of intermediate virtual states. In the presence of some disorder, the latter mechanism dominates at low temperatures, where the length of the hops grows to optimize the conductivity. This transport mechanism was introduced by Mott, and is called variable range hopping. When the Coulomb interaction between localized electrons is taken into account, it can be shown that at a sufficiently low temperature, variable range hopping conductivity obeys the Efros-Shklovskii (ES) law, which has been observed in a number of amorphous semiconductors and granular metal systems at low temperatures. ES conductivity has been long understood as the result of a soft, Coulomb gap at the Fermi level. However, such a theory overlooks the presence of spatial correlations between site energies and their possible effects on electrical conductivity. In this talk, we show both analytically and numerically that in systems where spatial correlations must be taken into account, ES conductivity may persist far outside the Coulomb gap, in contrast to conventional transport theory for doped semiconductors and Coulomb glasses where ES conductivity only occurs within the Coulomb gap.

  11. Orchestration of microtubules and the actin cytoskeleton in trichome cell shape determination by a plant-unique kinesin

    PubMed Central

    Tian, Juan; Han, Libo; Feng, Zhidi; Wang, Guangda; Liu, Weiwei; Ma, Yinping; Yu, Yanjun; Kong, Zhaosheng

    2015-01-01

    Microtubules (MTs) and actin filaments (F-actin) function cooperatively to regulate plant cell morphogenesis. However, the mechanisms underlying the crosstalk between these two cytoskeletal systems, particularly in cell shape control, remain largely unknown. In this study, we show that introduction of the MyTH4-FERM tandem into KCBP (kinesin-like calmodulin-binding protein) during evolution conferred novel functions. The MyTH4 domain and the FERM domain in the N-terminal tail of KCBP physically bind to MTs and F-actin, respectively. During trichome morphogenesis, KCBP distributes in a specific cortical gradient and concentrates at the branching sites and the apexes of elongating branches, which lack MTs but have cortical F-actin. Further, live-cell imaging and genetic analyses revealed that KCBP acts as a hub integrating MTs and actin filaments to assemble the required cytoskeletal configuration for the unique, polarized diffuse growth pattern during trichome cell morphogenesis. Our findings provide significant insights into the mechanisms underlying cytoskeletal regulation of cell shape determination. DOI: http://dx.doi.org/10.7554/eLife.09351.001 PMID:26287478

  12. Cultivated Grapevines Represent a Symptomless Reservoir for the Transmission of Hop Stunt Viroid to Hop Crops: 15 Years of Evolutionary Analysis

    PubMed Central

    Kawaguchi-Ito, Yoko; Li, Shi-Fang; Tagawa, Masaya; Araki, Hiroyuki; Goshono, Masafumi; Yamamoto, Shingen; Tanaka, Mayumi; Narita, Masako; Tanaka, Kazuaki; Liu, Sheng-Xue; Shikata, Eishiro; Sano, Teruo

    2009-01-01

    Hop stunt was a mysterious disorder that first emerged in the 1940s in commercial hops in Japan. To investigate the origin of this disorder, we infected hops with natural Hop stunt viroid (HpSVd) isolates derived from four host species (hop, grapevine, plum and citrus), which except for hop represent possible sources of the ancestral viroid. These plants were maintained for 15 years, then analyzed the HpSVd variants present. Here we show that the variant originally found in cultivated grapevines gave rise to various combinations of mutations at positions 25, 26, 54, 193, and 281. However, upon prolonged infection, these variants underwent convergent evolution resulting in a limited number of adapted mutants. Some of them showed nucleotide sequences identical to those currently responsible for hop stunt epidemics in commercial hops in Japan, China, and the United States. Therefore, these results indicate that we have successfully reproduced the original process by which a natural HpSVd variant naturally introduced into cultivated hops was able to mutate into the HpSVd variants that are currently present in commercial hops. Furthermore, and importantly, we have identified cultivated grapevines as a symptomless reservoir in which HSVd can evolve and be transmitted to hop crops to cause epidemics. PMID:20041179

  13. Carbon films embedded by nickel nanoparticles: fluctuation in hopping rate and variable-range hopping with respect to annealing temperature

    NASA Astrophysics Data System (ADS)

    Dalouji, Vali; Elahi, Smohammad; Solaymani, Shahram; Ghaderi, Atefeh; Elahi, Hossein

    2016-05-01

    In this work, the electrical properties of carbon-nickel films annealed at different temperatures (573, 773, 1073 and 1273 K) in the temperature range 15-300 K were investigated. The films were grown by radio frequency magnetron co-sputtering on quartz substrates at room temperature. The multiphonon hopping conduction mechanism is found to dominate the electrical transport in the temperature range 150-300 K. It can be seen that the room-temperature hopping rate (ΓRT) at 773 K has maximum value of 56.8 × 105 s-1. Our results of conductivity measurements at high temperature are in good agreement with strong carrier-lattice coupling model; on the other hand, the conductivity in the range 15-50 K is well described in terms of variable-range hopping (VRH) conduction mechanism. The localized state density around Fermi level N( E F) and the average hopping energy W hop at low temperature for the films annealed at 773 K have maximum value of 2.23 × 1023 (cm-3 eV-1) and minimum value of 9.74 × 10-4 eV, respectively.

  14. Gel-based and gel-free proteomic analysis of Nicotiana tabacum trichomes identifies proteins involved in secondary metabolism and in the (a)biotic stress response.

    PubMed

    Van Cutsem, Emmanuel; Simonart, Géraldine; Degand, Hervé; Faber, Anne-Marie; Morsomme, Pierre; Boutry, Marc

    2011-02-01

    Nicotiana tabacum leaves are covered by trichomes involved in the secretion of large amounts of secondary metabolites, some of which play a major role in plant defense. However, little is known about the metabolic pathways that operate in these structures. We undertook a proteomic analysis of N. tabacum trichomes in order to identify their protein complement. Efficient trichome isolation was obtained by abrading frozen leaves. After homogenization, soluble proteins and a microsomal fraction were prepared by centrifugation. Gel-based and gel-free proteomic analyses were then performed. 2-DE analysis of soluble proteins led to the identification of 1373 protein spots, which were digested and analyzed by MS/MS, leading to 680 unique identifications. Both soluble proteins and microsomal fraction were analyzed by LC MALDI-MS/MS after trypsin digestion, leading to 858 identifications, many of which had not been identified after 2-DE, indicating that the two methods complement each other. Many enzymes putatively involved in secondary metabolism were identified, including enzymes involved in the synthesis of terpenoid precursors and in acyl sugar production. Several transporters were also identified, some of which might be involved in secondary metabolite transport. Various (a)biotic stress response proteins were also detected, supporting the role of trichomes in plant defense. PMID:21268273

  15. Ectopic expression of R3 MYB transcription factor gene OsTCL1 in Arabidopsis, but not rice, affects trichome and root hair formation.

    PubMed

    Zheng, Kaijie; Tian, Hainan; Hu, Qingnan; Guo, Hongyan; Yang, Li; Cai, Ling; Wang, Xutong; Liu, Bao; Wang, Shucai

    2016-01-01

    In Arabidopsis, a MYB-bHLH-WD40 (MBW) transcriptional activator complex activates the homeodomain protein gene GLABRA2 (GL2), leading to the promotion of trichome formation and inhibition of root hair formation. The same MBW complex also activates single-repeat R3 MYB genes. R3 MYBs in turn, play a negative feedback role by competing with R2R3 MYB proteins for binding bHLH proteins, thus blocking the formation of the MBW complex. By BLASTing the rice (Oryza sativa) protein database using the entire amino acid sequence of Arabidopsis R3 MYB transcription factor TRICHOMELESS1 (TCL1), we found that there are two genes in rice genome encoding R3 MYB transcription factors, namely Oryza sativa TRICHOMELESS1 (OsTCL1) and OsTCL2. Expressing OsTCL1 in Arabidopsis inhibited trichome formation and promoted root hair formation, and OsTCL1 interacted with GL3 when tested in Arabidopsis protoplasts. Consistent with these observations, expression levels of GL2, R2R3 MYB transcription factor gene GLABRA1 (GL1) and several R3 MYB genes were greatly reduced, indicating that OsTCL1 is functional R3 MYB. However, trichome and root hair formation in transgenic rice plants overexpressing OsTCL1 remained largely unchanged, and elevated expression of OsGL2 was observed in the transgenic rice plants, indicating that rice may use different mechanisms to regulate trichome formation. PMID:26758286

  16. Ectopic expression of R3 MYB transcription factor gene OsTCL1 in Arabidopsis, but not rice, affects trichome and root hair formation

    PubMed Central

    Zheng, Kaijie; Tian, Hainan; Hu, Qingnan; Guo, Hongyan; Yang, Li; Cai, Ling; Wang, Xutong; Liu, Bao; Wang, Shucai

    2016-01-01

    In Arabidopsis, a MYB-bHLH-WD40 (MBW) transcriptional activator complex activates the homeodomain protein gene GLABRA2 (GL2), leading to the promotion of trichome formation and inhibition of root hair formation. The same MBW complex also activates single-repeat R3 MYB genes. R3 MYBs in turn, play a negative feedback role by competing with R2R3 MYB proteins for binding bHLH proteins, thus blocking the formation of the MBW complex. By BLASTing the rice (Oryza sativa) protein database using the entire amino acid sequence of Arabidopsis R3 MYB transcription factor TRICHOMELESS1 (TCL1), we found that there are two genes in rice genome encoding R3 MYB transcription factors, namely Oryza sativa TRICHOMELESS1 (OsTCL1) and OsTCL2. Expressing OsTCL1 in Arabidopsis inhibited trichome formation and promoted root hair formation, and OsTCL1 interacted with GL3 when tested in Arabidopsis protoplasts. Consistent with these observations, expression levels of GL2, R2R3 MYB transcription factor gene GLABRA1 (GL1) and several R3 MYB genes were greatly reduced, indicating that OsTCL1 is functional R3 MYB. However, trichome and root hair formation in transgenic rice plants overexpressing OsTCL1 remained largely unchanged, and elevated expression of OsGL2 was observed in the transgenic rice plants, indicating that rice may use different mechanisms to regulate trichome formation. PMID:26758286

  17. Starting with Style: Toward a Second Wave of Hip-Hop Education Research and Practice

    ERIC Educational Resources Information Center

    Petchauer, Emery

    2015-01-01

    One fundamental breakthrough in the field of hip-hop education in recent years is the shift from understanding hip-hop solely as content to understanding hip-hop also as aesthetic form. In this article, I chart the roots of this shift across disciplines and focus on what it might mean for the future of hip-hop education, pedagogy, and research in…

  18. Effect of light on hopping conduction in kesterite CZTS thin films

    NASA Astrophysics Data System (ADS)

    Ghediya, Prashant R.; Chaudhuri, Tapas K.; Ray, Jaymin R.

    2016-05-01

    Mott variable range hopping conduction in dip-coated CZTS thin films has been studied in the temperature range of 77 to 150 K in dark and under different light intensities. The films were basically p-type and photoconducting. Various hopping parameters such as, Mott characteristic temperature, density of states at Fermi level, hopping distance and hopping energy of the CZTS films were investigated for different light intensities.

  19. "Deeper than Rap": Gifted Males and Their Relationship with Hip Hop Culture

    ERIC Educational Resources Information Center

    Callahan, J. Sean; Grantham, Tarek C.

    2012-01-01

    One would be hard-pressed to deny the impact that hip hop is having on gifted students. More specifically, because hip hop is a creative and exciting male-dominated culture, gifted males gravitate to hip hop culture. From the perspective of two Black men from two different generations, this article was inspired by discussions about the role of hip…

  20. Behind Beats and Rhymes: Working Class from a Hampton Roads Hip Hop Homeplace

    ERIC Educational Resources Information Center

    Durham, Aisha S.

    2009-01-01

    The film documentary titled "Hip Hop: beyond beats and rhymes" captures ongoing conversations among scholars, cultural critics, and hip hop insiders about the state of African Americans by interrogating distinct expressive forms associated with hip hop culture. Durham draws from two scenes to describe her memories as the researched underclass and…

  1. Beats, Rhymes, and Classroom Life: Hip-Hop Pedagogy and the Politics of Identity

    ERIC Educational Resources Information Center

    Hill, Marc Lamont

    2009-01-01

    For over a decade, educators have looked to capitalize on the appeal of hip-hop culture, sampling its language, techniques, and styles as a way of reaching out to students. But beyond a fashionable hipness, what does hip-hop have to offer our schools? In this revelatory new book, Marc Lamont Hill shows how a serious engagement with hip-hop culture…

  2. Wish to Live: The Hip-Hop Feminism Pedagogy Reader. Educational Psychology. Volume 3

    ERIC Educational Resources Information Center

    Brown, Ruth Nicole, Ed.; Kwakye, Chamara Jewel, Ed.

    2012-01-01

    "Wish To Live: The Hip-hop Feminism Pedagogy Reader" moves beyond the traditional understanding of the four elements of hip-hop culture--rapping, breakdancing, graffiti art, and deejaying--to articulate how hip-hop feminist scholarship can inform educational practices and spark, transform, encourage, and sustain local and global youth community…

  3. Sequential sampling for estimation and classification of the incidence of hop powdery mildew I: Leaf sampling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hop powdery mildew (caused by Podosphaera macularis) is an important disease of hops (Humulus lupulus) in the Pacific Northwest. Sequential sampling models for estimation and classification of the incidence of powdery mildew on leaves of hop were developed based on the beta-binomial distribution, u...

  4. Precision QTL mapping of downy mildew resistance in Hop (Humulus lupulus L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hop Downy mildew (DM) is an obligate parasite causing severe losses in hop if not controlled. Resistance to this pathogen is a primary goal for hop breeding programs. The objective of this study was to identify QTLs linked to DM resistance. Next-generation-sequencing was performed on a mapping po...

  5. Flipping the Misogynist Script: Gender, Agency, Hip Hop and Music Education

    ERIC Educational Resources Information Center

    Tobias, Evan S.

    2014-01-01

    Excluding Hip Hop culture and rap music from music education misses opportunities for addressing key aspects of popular culture, society, and students' lives. This article addresses intersections of Hip Hop, gender, and music education to forward potential Hip Hop praxis. After tracing related scholarship, I discuss and problematize…

  6. Hopping locomotion at different gravity: metabolism and mechanics in humans.

    PubMed

    Pavei, Gaspare; Minetti, Alberto E

    2016-05-15

    Previous literature on the effects of low gravity on the mechanics and energetics of human locomotion already dealt with walking, running, and skipping. The aim of the present study is to obtain a comprehensive view on that subject by including measurements of human hopping in simulated low gravity, a gait often adopted in many Apollo Missions and documented in NASA footage. Six subjects hopped at different speeds at terrestrial, Martian, and Lunar gravity on a treadmill while oxygen consumption and 3D body kinematic were sampled. Results clearly indicate that hopping is too metabolically expensive to be a sustainable locomotion on Earth but, similarly to skipping (and running), its economy greatly (more than ×10) increases at lower gravity. On the Moon, the metabolic cost of hopping becomes even lower than that of walking, skipping, and running, but the general finding is that gaits with very different economy on Earth share almost the same economy on the Moon. The mechanical reasons for such a decrease in cost are discussed in the paper. The present data, together with previous findings, will allow also to predict the aerobic traverse range/duration of astronauts when getting far from their base station on low gravity planets. PMID:26635350

  7. Chicano Hip-Hop as Interethnic Contact Zone

    ERIC Educational Resources Information Center

    McFarland, Pancho

    2008-01-01

    Hip-hop is an interethnic contact zone that allows for the creation of new expressive cultures and new identities for young people. Its openness derives in part from the wide range of expression and interpretation allowed in 182 "McFarland" African musics. Moving beyond the often stifling options offered by an earlier generation that focused on…

  8. Crossing the Lexicon: Anglicisms in the German Hip Hop Community

    ERIC Educational Resources Information Center

    Garley, Matthew E.

    2012-01-01

    The influence of English on German has been an ongoing subject of intense popular and academic interest in the German sphere. In order to better understand this language contact situation, this research project investigates anglicisms--instances of English language material in a German language context--in the German hip hop community, where the…

  9. Examining Hip-Hop as Culturally Relevant Pedagogy

    ERIC Educational Resources Information Center

    Kim, Jung; Pulido, Isaura

    2015-01-01

    Culturally relevant pedagogy is a framework that conceptualizes the process of student learning as contingent upon educators' deep understanding of students' cultural backgrounds to co-construct knowledge and develop academic skills. Concurrently, there are a growing number of studies that explore hip-hop as a culturally relevant curriculum for…

  10. Young Children Manifest Spiritualities in Their Hip-Hop Writing

    ERIC Educational Resources Information Center

    Norton, Nadjwa E. L.

    2014-01-01

    In this article, the author combines multicultural feminist critical theories with the voices of Black and Latina/Latino young spiritual children to extend culturally responsive teaching. The author illuminates how children use their hip-hop writing to construct themselves as people who communicate with God, choose spiritual content for their…

  11. Critical Hip Hop Pedagogy as a Form of Liberatory Praxis

    ERIC Educational Resources Information Center

    Akom, A. A.

    2009-01-01

    This article uses Paulo Freire's problem-posing method, youth participatory action research, and case study methodology to introduce an alternative instructional strategy called Critical Hip Hop Pedagogy (CHHP). This approach attempts to address deep-rooted ideologies to social inequities by creating a space in teacher education courses for…

  12. Molecular mechanisms of Tetranychus urticae chemical adaptation in hop fields.

    PubMed

    Piraneo, Tara G; Bull, Jon; Morales, Mariany A; Lavine, Laura C; Walsh, Douglas B; Zhu, Fang

    2015-01-01

    The two-spotted spider mite, Tetranychus urticae Koch is a major pest that feeds on >1,100 plant species. Many perennial crops including hop (Humulus lupulus) are routinely plagued by T. urticae infestations. Hop is a specialty crop in Pacific Northwest states, where 99% of all U.S. hops are produced. To suppress T. urticae, growers often apply various acaricides. Unfortunately T. urticae has been documented to quickly develop resistance to these acaricides which directly cause control failures. Here, we investigated resistance ratios and distribution of multiple resistance-associated mutations in field collected T. urticae samples compared with a susceptible population. Our research revealed that a mutation in the cytochrome b gene (G126S) in 35% tested T. urticae populations and a mutation in the voltage-gated sodium channel gene (F1538I) in 66.7% populations may contribute resistance to bifenazate and bifenthrin, respectively. No mutations were detected in Glutamate-gated chloride channel subunits tested, suggesting target site insensitivity may not be important in our hop T. urticae resistance to abamectin. However, P450-mediated detoxification was observed and is a putative mechanism for abamectin resistance. Molecular mechanisms of T. urticae chemical adaptation in hopyards is imperative new information that will help growers develop effective and sustainable management strategies. PMID:26621458

  13. Photon assisted hopping conduction mechanism in Tl2SSe crystals

    NASA Astrophysics Data System (ADS)

    Qasrawi, A. F.; Ziqan, Abdelhalim M.; Jazzar, Suha Kh.; Gasanly, N. M.

    2015-02-01

    In this article, the powder X-ray diffraction data and the dark and the photo-excited electrical conduction parameters of Tl2SSe crystal are reported. The dark and photon excited electrical conduction in the tetragonal crystal are found to be dominated by thermionic emission assisted variable range hopping conduction (VRH). The dark Mott's VRH parameters representing by the degree of disorder (To), the density of localized states near the Fermi level (N (EF)), the average hopping range (R) and average hopping energy (W) exhibited wide tunability via incremental photon intensity. Particularly, while the dark values of T0 , W and R significantly decreased from 2.32 ×108 to 1.52 ×105 K, 114 to 18.25 meV and from 66.15 to 10.58 A°, respectively, the values of N (EF) increased from 7.23 ×1018 to 1.10 ×1022cm-3 /eV when the crystal was photo-excited with a 53.6 mW/cm2 light intensity. These variations in the hopping parameters via photon excitations are promisig for using the crystal in the fabrication of well controlled, widely tunable, low energy consuming and highly efficient electronic devices.

  14. Analytical methods for quantitation of prenylated flavonoids from hops

    PubMed Central

    Nikolić, Dejan; van Breemen, Richard B.

    2013-01-01

    The female flowers of hops (Humulus lupulus L.) are used as a flavoring agent in the brewing industry. There is growing interest in possible health benefits of hops, particularly as estrogenic and chemopreventive agents. Among the possible active constituents, most of the attention has focused on prenylated flavonoids, which can chemically be classified as prenylated chalcones and prenylated flavanones. Among chalcones, xanthohumol (XN) and desmethylxanthohumol (DMX) have been the most studied, while among flavanones, 8-prenylnaringenin (8-PN) and 6-prenylnaringenin (6-PN) have received the most attention. Because of the interest in medicinal properties of prenylated flavonoids, there is demand for accurate, reproducible and sensitive analytical methods to quantify these compounds in various matrices. Such methods are needed, for example, for quality control and standardization of hop extracts, measurement of the content of prenylated flavonoids in beer, and to determine pharmacokinetic properties of prenylated flavonoids in animals and humans. This review summarizes currently available analytical methods for quantitative analysis of the major prenylated flavonoids, with an emphasis on the LC-MS and LC-MS-MS methods and their recent applications to biomedical research on hops. This review covers all methods in which prenylated flavonoids have been measured, either as the primary analytes or as a part of a larger group of analytes. The review also discusses methodological issues relating to the quantitative analysis of these compounds regardless of the chosen analytical approach. PMID:24077106

  15. Powdery Mildew Resistant Hop Germplasm Release: 'Kazak 2000'

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A USDA-sponsored plant collecting expedition in collaboration with the Vavilov Institute of Plant Industry (VIR), St. Petersburg, Russian Federation, and the Aral Sea Experiment Station for Plant Genetic Resources, Chelkar Town, Kazakhstan, was conducted in the fall of 2000. Hop cones were collecte...

  16. Metazoan cell biology of the HOPS tethering complex

    PubMed Central

    Zlatic, Stephanie A; Tornieri, Karine; L'Hernault, Steven W

    2011-01-01

    Membrane fusion with vacuoles, the lysosome equivalent of the yeast Saccharomyces cerevisiae, is among the best understood membrane fusion events. Our precise understanding of this fusion machinery stems from powerful genetics and elegant in vitro reconstitution assays. Central to vacuolar membrane fusion is the multi-subunit tether the HO motypic fusion and Protein Sorting (HOPS) complex, a complex of proteins that organizes other necessary components of the fusion machinery. We lack a similarly detailed molecular understanding of membrane fusion with lysosomes or lysosome-related organelles in metazoans. However, it is likely that fundamental principles of how rabs, SNAREs and HOPS tethers work to fuse membranes with lysosomes and related organelles are conserved between Saccharomyces cerevisiae and metazoans. Here, we discuss emerging differences in the coat-dependent mechanisms that govern HOPS complex subcellular distribution between Saccharomyces cerevisiae and metazoans. These differences reside upstream of the membrane fusion event. We propose that the differences in how coats segregate class C Vps/HOPS tethers to organelles and domains of metazoan cells are adaptations to complex architectures that characterize metazoan cells such as those of neuronal and epithelial tissues. PMID:21922076

  17. Differential design for hopping in two species of wallabies.

    PubMed

    McGowan, C P; Baudinette, R V; Biewener, A A

    2008-06-01

    Hindlimb musculoskeletal anatomy and steady speed over ground hopping mechanics were compared in two species of macropod marsupials, tammar wallabies and yellow-footed rock wallabies (YFRW). These two species are relatively closely related and are of similar size and general body plan, yet they inhabit different environments with presumably different musculoskeletal demands. Tammar wallabies live in relatively flat, open habitat whereas yellow-footed rock wallabies inhabit steep cliff faces. The goal of this study was to explore musculoskeletal differences between tammar wallabies and yellow-footed rock wallabies and determine how these differences influence each species' hopping mechanics. We found the cross-sectional area of the combined ankle extensor tendons of yellow-footed rock wallabies was 13% greater than that of tammar wallabies. Both species experienced similar ankle joint moments during steady-speed hopping, however due to a lower mechanical advantage at this joint, tammar wallabies produced 26% more muscle force. Thus, during moderate speed hopping, yellow-footed rock wallabies operated with 38% higher tendon safety factors, while tammar wallabies were able to store 73% more elastic strain energy (2.18 J per leg vs. 1.26 J in YFRW). This likely reflects the differing demands of the environments inhabited by these two species, where selection for non-steady locomotor performance in rocky terrain likely requires trade-offs in locomotor economy. PMID:16861021

  18. 21 CFR 172.560 - Modified hop extract.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Modified hop extract. 172.560 Section 172.560 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Flavoring Agents and Related Substances...

  19. 21 CFR 172.560 - Modified hop extract.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Modified hop extract. 172.560 Section 172.560 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Flavoring Agents and Related Substances...

  20. Contribution of afferent feedback and descending drive to human hopping

    PubMed Central

    Zuur, Abraham T; Lundbye-Jensen, Jesper; Leukel, Christian; Taube, Wolfgang; Grey, Michael J; Gollhofer, Albert; Nielsen, Jens Bo; Gruber, Markus

    2010-01-01

    During hopping an early burst can be observed in the EMG from the soleus muscle starting about 45 ms after touch-down. It may be speculated that this early EMG burst is a stretch reflex response superimposed on activity from a supra-spinal origin. We hypothesised that if a stretch reflex indeed contributes to the early EMG burst, then advancing or delaying the touch-down without the subject's knowledge should similarly advance or delay the burst. This was indeed the case when touch-down was advanced or delayed by shifting the height of a programmable platform up or down between two hops and this resulted in a correspondent shift of the early EMG burst. Our second hypothesis was that the motor cortex contributes to the first EMG burst during hopping. If so, inhibition of the motor cortex would reduce the magnitude of the burst. By applying a low-intensity magnetic stimulus it was possible to inhibit the motor cortex and this resulted in a suppression of the early EMG burst. These results suggest that sensory feedback and descending drive from the motor cortex are integrated to drive the motor neuron pool during the early EMG burst in hopping. Thus, simple reflexes work in concert with higher order structures to produce this repetitive movement. PMID:20064857

  1. AFLP Discrimination of Wild American and Cultivated Hop

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hop breeding historically relied upon relatively simple selection techniques within established breeding lines. Relying on a narrow genetic base to address production problems may lead to a genetic bottleneck in breeding germplasm, and may limit a breeder's ability to select for new traits. The obje...

  2. Cryopreservation and maintenance of hop material in USDA germplasm collection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The National Clonal Germplasm Repository (NCGR-Corvallis) is responsible for conservation of the hop (Humulus lupulus L.) genetic resources for the US Department of Agriculture (USDA), Agricultural Research Service (ARS). The collection includes 675 accessions representing 7 related taxa (species an...

  3. Metazoan cell biology of the HOPS tethering complex.

    PubMed

    Zlatic, Stephanie A; Tornieri, Karine; L'hernault, Steven W; Faundez, Victor

    2011-05-01

    Membrane fusion with vacuoles, the lysosome equivalent of the yeast Saccharomyces cerevisiae, is among the best understood membrane fusion events. Our precise understanding of this fusion machinery stems from powerful genetics and elegant in vitro reconstitution assays. Central to vacuolar membrane fusion is the multi-subunit tether the HO motypic fusion and Protein Sorting (HOPS) complex, a complex of proteins that organizes other necessary components of the fusion machinery. We lack a similarly detailed molecular understanding of membrane fusion with lysosomes or lysosome-related organelles in metazoans. However, it is likely that fundamental principles of how rabs, SNAREs and HOPS tethers work to fuse membranes with lysosomes and related organelles are conserved between Saccharomyces cerevisiae and metazoans. Here, we discuss emerging differences in the coat-dependent mechanisms that govern HOPS complex subcellular distribution between Saccharomyces cerevisiae and metazoans. These differences reside upstream of the membrane fusion event. We propose that the differences in how coats segregate class C Vps/HOPS tethers to organelles and domains of metazoan cells are adaptations to complex architectures that characterize metazoan cells such as those of neuronal and epithelial tissues. PMID:21922076

  4. Recent Progress in Surface Hopping: 2011-2015.

    PubMed

    Wang, Linjun; Akimov, Alexey; Prezhdo, Oleg V

    2016-06-01

    Developed 25 years ago, Tully's fewest switches surface hopping (FSSH) has proven to be the most popular approach for simulating quantum-classical dynamics in a broad variety of systems, ranging from the gas phase, to the liquid and solid phases, to biological and nanoscale materials. FSSH is widely adopted as the fundamental platform to introduce modifications as needed. Significant progress has been made recently to enhance the accuracy and efficiency of the surface hopping technique. Various limitations of the standard FSSH-associated with quantum nuclear effects, interference and decoherence, trivial or "unavoided" crossings, superexchange, and representation dependence-have been lifted. These advances are needed to allow one to treat many important phenomena in chemistry, physics, materials, and related disciplines. Examples include charge transport in extended systems such as organic solids, singlet fission in molecular aggregates, Auger-type exciton multiplication, recombination and relaxation in quantum dots and other nanoscale materials, Auger-assisted charge transfer, nonradiative luminescence quenching, and electron-hole recombination. This Perspective summarizes recent advances in the surface hopping formulation of nonadiabatic dynamics and provides an outlook on the future of surface hopping. PMID:27171314

  5. Analytical methods for quantitation of prenylated flavonoids from hops.

    PubMed

    Nikolić, Dejan; van Breemen, Richard B

    2013-01-01

    The female flowers of hops (Humulus lupulus L.) are used as a flavoring agent in the brewing industry. There is growing interest in possible health benefits of hops, particularly as estrogenic and chemopreventive agents. Among the possible active constituents, most of the attention has focused on prenylated flavonoids, which can chemically be classified as prenylated chalcones and prenylated flavanones. Among chalcones, xanthohumol (XN) and desmethylxanthohumol (DMX) have been the most studied, while among flavanones, 8-prenylnaringenin (8-PN) and 6-prenylnaringenin (6-PN) have received the most attention. Because of the interest in medicinal properties of prenylated flavonoids, there is demand for accurate, reproducible and sensitive analytical methods to quantify these compounds in various matrices. Such methods are needed, for example, for quality control and standardization of hop extracts, measurement of the content of prenylated flavonoids in beer, and to determine pharmacokinetic properties of prenylated flavonoids in animals and humans. This review summarizes currently available analytical methods for quantitative analysis of the major prenylated flavonoids, with an emphasis on the LC-MS and LC-MS-MS methods and their recent applications to biomedical research on hops. This review covers all methods in which prenylated flavonoids have been measured, either as the primary analytes or as a part of a larger group of analytes. The review also discusses methodological issues relating to the quantitative analysis of these compounds regardless of the chosen analytical approach. PMID:24077106

  6. Molecular mechanisms of Tetranychus urticae chemical adaptation in hop fields

    PubMed Central

    Piraneo, Tara G.; Bull, Jon; Morales, Mariany A.; Lavine, Laura C.; Walsh, Douglas B.; Zhu, Fang

    2015-01-01

    The two-spotted spider mite, Tetranychus urticae Koch is a major pest that feeds on >1,100 plant species. Many perennial crops including hop (Humulus lupulus) are routinely plagued by T. urticae infestations. Hop is a specialty crop in Pacific Northwest states, where 99% of all U.S. hops are produced. To suppress T. urticae, growers often apply various acaricides. Unfortunately T. urticae has been documented to quickly develop resistance to these acaricides which directly cause control failures. Here, we investigated resistance ratios and distribution of multiple resistance-associated mutations in field collected T. urticae samples compared with a susceptible population. Our research revealed that a mutation in the cytochrome b gene (G126S) in 35% tested T. urticae populations and a mutation in the voltage-gated sodium channel gene (F1538I) in 66.7% populations may contribute resistance to bifenazate and bifenthrin, respectively. No mutations were detected in Glutamate-gated chloride channel subunits tested, suggesting target site insensitivity may not be important in our hop T. urticae resistance to abamectin. However, P450-mediated detoxification was observed and is a putative mechanism for abamectin resistance. Molecular mechanisms of T. urticae chemical adaptation in hopyards is imperative new information that will help growers develop effective and sustainable management strategies. PMID:26621458

  7. Hopping Diffusion of Nanoparticles Subjected to Topological Constraints

    NASA Astrophysics Data System (ADS)

    Cai, Li-Heng; Panyukov, Sergey; Rubinstein, Michael

    2013-03-01

    We describe a novel hopping mechanism for diffusion of large non-sticky nanoparticles subjected to topological constraints in polymer solids (networks and gels) and entangled polymer liquids (melts and solutions). Probe particles with size larger than the mesh size of unentangled polymer networks (tube diameter of entangled polymer liquids) are trapped by the network (entanglement) cages at time scales longer than the relaxation time of the network (entanglement) strand. At long time scales, however, these particles can move further by hopping between neighboring confinement cages. This hopping is controlled by fluctuations of surrounding confinement cages, which could be large enough to allow particles to slip through. The terminal particle diffusion coefficient dominated by this hopping diffusion is appreciable for particles with size slightly larger than the network mesh size (tube diameter). Very large particles in polymer solids will be permanently trapped by local network cages, whereas they can still move in polymer liquids by waiting for entanglement cages to rearrange on the relaxation time scale of the liquids. We would like to acknowledge the financial support of NSF CHE-0911588, DMR-0907515, DMR-1121107, DMR-1122483, and CBET-0609087, NIH R01HL077546 and P50HL107168, and Cystic Fibrosis Foundation under grant RUBIN09XX0.

  8. GEOPHYSICS, ASTRONOMY AND ASTROPHYSICS: Second-harmonic generation as a DNA malignancy indicator of prostate glandular epithelial cells

    NASA Astrophysics Data System (ADS)

    Zhuang, Zheng-Fei; Liu, Han-Ping; Guo, Zhou-Yi; Zhuo, Shuang-Mu; Yu, Bi-Ying; Deng, Xiao-Yuan

    2010-04-01

    This paper first demonstrates second-harmonic generation (SHG) in the intact cell nucleus, which acts as an optical indicator of DNA malignancy in prostate glandular epithelial cells. Within a scanning region of 2.7 μm×2.7 μm in cell nuclei, SHG signals produced from benign prostatic hyperplasia (BPH) and prostate carcinoma (PC) tissues (mouse model C57BL/6) have been investigated. Statistical analyses (t test) of a total of 405 measurements (204 nuclei from BPH and 201 nuclei from PC) show that SHG signals from BPH and PC have a distinct difference (p < 0.05), suggesting a potential optical method of revealing very early malignancy in prostate glandular epithelial cells based upon induced biochemical and/or biophysical modifications in DNA.

  9. Single-cell analysis of glandular T cell receptors in Sjögren’s syndrome

    PubMed Central

    Joachims, Michelle L.; Leehan, Kerry M.; Lawrence, Christina; Pelikan, Richard C.; Moore, Jacen S.; Pan, Zijian; Rasmussen, Astrid; Radfar, Lida; Lewis, David M.; Grundahl, Kiely M.; Kelly, Jennifer A.; Wiley, Graham B.; Shugay, Mikhail; Chudakov, Dmitriy M.; Lessard, Christopher J.; Stone, Donald U.; Scofield, R. Hal; Montgomery, Courtney G.; Sivils, Kathy L.; Thompson, Linda F.; Farris, A. Darise

    2016-01-01

    CD4+ T cells predominate in salivary gland (SG) inflammatory lesions in Sjögren’s syndrome (SS). However, their antigen specificity, degree of clonal expansion, and relationship to clinical disease features remain unknown. We used multiplex reverse-transcriptase PCR to amplify paired T cell receptor α (TCRα) and β transcripts of single CD4+CD45RA− T cells from SG and peripheral blood (PB) of 10 individuals with primary SS, 9 of whom shared the HLA DR3/DQ2 risk haplotype. TCRα and β sequences were obtained from a median of 91 SG and 107 PB cells per subject. The degree of clonal expansion and frequency of cells expressing two productively rearranged α genes were increased in SG versus PB. Expanded clones from SG exhibited complementary-determining region 3 (CDR3) sequence similarity both within and among subjects, suggesting antigenic selection and shared antigen recognition. CDR3 similarities were shared among expanded clones from individuals discordant for canonical Ro and La autoantibodies, suggesting recognition of alternative SG antigen(s). The extent of SG clonal expansion correlated with reduced saliva production and increased SG fibrosis, linking expanded SG T cells with glandular dysfunction. Knowledge of paired TCRα and β sequences enables further work toward identification of target antigens and development of novel therapies. PMID:27358913

  10. Identification of cholinergic chemosensory cells in mouse tracheal and laryngeal glandular ducts.

    PubMed

    Krasteva-Christ, G; Soultanova, A; Schütz, B; Papadakis, T; Weiss, C; Deckmann, K; Chubanov, V; Gudermann, T; Voigt, A; Meyerhof, W; Boehm, U; Weihe, E; Kummer, W

    2015-11-01

    Specialized epithelial cells in the respiratory tract such as solitary chemosensory cells and brush cells sense the luminal content and initiate protective reflexes in response to the detection of potentially harmful substances. The majority of these cells are cholinergic and utilize the canonical taste signal transduction cascade to detect "bitter" substances such as bacterial quorum sensing molecules. Utilizing two different mouse strains reporting expression of choline acetyltransferase (ChAT), the synthesizing enzyme of acetylcholine (ACh), we detected cholinergic cells in the submucosal glands of the murine larynx and trachea. These cells were localized in the ciliated glandular ducts and were neither found in the collecting ducts nor in alveolar or tubular segments of the glands. ChAT expression in tracheal gland ducts was confirmed by in situ hybridization. The cholinergic duct cells expressed the brush cell marker proteins, villin and cytokeratin-18, and were immunoreactive for components of the taste signal transduction cascade (Gα-gustducin, transient receptor potential melastatin-like subtype 5 channel = TRPM5, phospholipase C(β2)), but not for carbonic anhydrase IV. Furthermore, these cells expressed the bitter taste receptor Tas2r131, as demonstrated utilizing an appropriate reporter mouse strain. Our study identified a previously unrecognized presumptive chemosensory cell type in the duct of the airway submucosal glands that likely utilizes ACh for paracrine signaling. We propose that these cells participate in infection-sensing mechanisms and initiate responses assisting bacterial clearance from the lower airways. PMID:26033492

  11. Mixed squamous cell and glandular papilloma of the lung: a case study and literature review.

    PubMed

    Inamura, Kentaro; Kumasaka, Toshio; Furuta, Reiko; Shimada, Kei; Hiyama, Noriko; Furuhata, Yoshiaki; Tanaka, Isao; Takemura, Tamiko

    2011-04-01

    Mixed squamous cell and glandular papilloma (mixed papilloma) of the lung is an extremely rare neoplasm, with only 10 cases reported so far in the English literature. We present a case study of endobronchial mixed papilloma with immunohistochemical and etiological investigations. A 49-year-old male with a smoking history complained of hemoptysis, presented with a lung mass closely adjacent to large vessels in the computed tomography findings, and underwent lobectomy. The 3.0-cm sized polypoid tumor was histologically diagnosed as endobronchial mixed papilloma. Immunohistochemically, intracellular mucin was positive for MUC5AC, which is expressed in tracheobronchial goblet cells. CAM5.2 and CK19 were diffusely positive, indicating that the tumor originated from the columnar epithelium by squamous metaplasia. CEA and CA19-9 were focally positive. A human papillomavirus (HPV) investigation with in situ hybridization using a wide spectrum probe and a newly-developed PCR system did not detect any HPV infection. Including this case with a detailed HPV investigation, all of the reported cases of mixed papilloma were HPV-negative, and a literature review including newly-reported cases indicated a high frequency of smoking in such cases. Endobronchial mixed papillomas might have a smoking-related etiology. PMID:21418399

  12. Glandular Odontogenic Cyst: Report of Two Cases and Review of Literature

    PubMed Central

    Sherlin, Herald J.; Ramalingam, Karthikeyan; Natesan, Anuja; Premkumar, Priya; Ramani, Pratibha; Chandrasekar, Thiruvengadam

    2009-01-01

    Glandular odontogenic cyst (GOC) is an uncommon jaw bone cyst of odontogenic origin described in 1987 by Gardner et al. It is a cyst having an unpredictable and potentially aggressive behaviour. It also has the propensity to grow to a large size and tendency to recur with only 111 cases having been reported thus far. The first case occurred in a 42-year-old female and presented as a localized swelling extending from 19 to 29 regions. There was a history of traumatic injury at the site. There was evidence of bicortical expansion and radiographs revealed a multilocular radiolucency. The second case occurred in a 21-year-old male, as a large swelling in the mandible and radiograph revealed radiolucency in the region. On histopathological examination, these lesions were diagnosed as GOC. It was concluded that, two cases submitted by us correlate with the existing literature that GOC’s affect more commonly in the middle age group, having predilection for mandible and that trauma could be a precipitating factor for its occurrence. The increased recurrence rates can be due to its intrinsic biological behavior, multilocularity of the cyst, and incomplete removal of the lining following conservative treatment. PMID:19644539

  13. Packet error probabilities in frequency-hopped spread spectrum packet radio networks. Markov frequency hopping patterns considered

    NASA Astrophysics Data System (ADS)

    Georgiopoulos, M.; Kazakos, P.

    1987-09-01

    We compute the packet error probability induced in a frequency-hopped spread spectrum packet radio network, which utilizes first order Markov frequency hopping patterns. The frequency spectrum is divided into q frequency bins and the packets are divided into M bytes each. Every user in the network sends each of the M bytes of his packet at a frequency bin, which is different from the frequency bin used by the previous byte, but equally likely to be any one of the remaining q-1 frequency bins (Markov frequency hopping patterns). Furthermore, different users in the network utilize statistically independent frequency hopping patterns. Provided that, K users have simultaneously transmitted their packets on the channel, and a receiver has locked on to one of these K packets, we present a method for the computation of P sub e (K) (i.e. the probability that this packet is incorrectly decoded). Furthermore, we present numerical results (i.e. P sub e (K) versus K) for various values of the multiple access interference K, when Reed Solomon (RS) codes are used for the encoding of packets. Finally, some useful comparisons, with the packet error probability induced, if we assume that the byte errors are independent, are made; based on these comparisons, we can easily evaluate the performance of our spread spectrum system.

  14. Communication: Proper treatment of classically forbidden electronic transitions significantly improves detailed balance in surface hopping.

    PubMed

    Sifain, Andrew E; Wang, Linjun; Prezhdo, Oleg V

    2016-06-01

    Surface hopping is the most popular method for nonadiabatic molecular dynamics. Many have reported that it does not rigorously attain detailed balance at thermal equilibrium, but does so approximately. We show that convergence to the Boltzmann populations is significantly improved when the nuclear velocity is reversed after a classically forbidden hop. The proposed prescription significantly reduces the total number of classically forbidden hops encountered along a trajectory, suggesting that some randomization in nuclear velocity is needed when classically forbidden hops constitute a large fraction of attempted hops. Our results are verified computationally using two- and three-level quantum subsystems, coupled to a classical bath undergoing Langevin dynamics. PMID:27276938

  15. Ultrastructure of posterior sternal glands of Macrotermes annandalei (Silvestri): new members of the sexual glandular set found in termites (Insecta).

    PubMed

    Quennedey, André; Peppuy, Alexis; Courrent, Annie; Robert, Alain; Everaerts, Claude; Bordereau, Christian

    2004-12-01

    In female alates of Macrotermes annandalei, two types of abdominal glands are involved in the secretion of sex pheromone. Tergal glands are found at the anterior margin of tergites 6-10 and posterior sternal glands (PSGs) are located at the anterior margin of sternites 6-7. The cytological features of both types of glands are quite similar. The fine structural organization of PSGs is studied more precisely and described for the first time. The glandular cuticle is pitted with narrow apertures corresponding to the openings of numerous subcuticular pouches. Several Class 3 glandular units open in each pouch. One canal cell and one secretory cell make an individual glandular unit. The canal cell is enlarged apically and is connected with the other canal cells to form a common pouch. Based on the structural features found in these glands, we propose a common secretory process for PSGs and tergal glands. During the physiological maturation of alates inside the nest, secretory vesicles amass in the cytoplasm of secretory cells, while large intercellular spaces collapse the cuticular pouches. At the time of dispersal flight, pouches are filled with the content of secretory vesicles while intercellular spaces are sharply reduced. After calling behavior, no secretion remains in the glands and pouches collapse again, while secretory cells are drastically reduced in size. The structure and the secretory processes of PSGs and tergal glands are compared to those of abdominal sexual glands known in termites. PMID:15487007

  16. Genetics and biochemistry of collagen binding-triggered glandular differentiation in a human colon carcinoma cell line

    SciTech Connect

    Pignatelli, M.; Bodmer, W.F. )

    1988-08-01

    The authors have examined the interaction between collagen binding and epithelial differentiation by using a human colon carcinoma cell line (SW1222) that can differentiate structurally when grown in a three-dimensional collagen gel to form glandular structures. As much as 66% inhibition of glandular differentiation can be achieved by addition to the culture of a synthetic peptide containing the Arg-Gly-Asp-Thr (RGDT) sequence, which is a cell recognition site found in collagen. Arg-Gly-Asp-Thr also inhibited the cell attachment to collagen-coated plates. Chromosome 15 was found in all human-mouse hybrid clones that could differentiate in the collagen gel and bind collagen. Both binding to collagen and glandular differentiation of the hybrid cells were also inhibited by Arg-Gly-Asp-Thr as for the parent cell line SW1222. The ability of SW1222 cells to express the differentiated phenotype appears, therefore, to be determined by an Arg-Gly-Asp-directed collagen receptor on the cell surface that is controlled by a gene on chromosome 15.

  17. The impact of hop bitter acid and polyphenol profiles on the perceived bitterness of beer.

    PubMed

    Oladokun, Olayide; Tarrega, Amparo; James, Sue; Smart, Katherine; Hort, Joanne; Cook, David

    2016-08-15

    Thirty-four commercial lager beers were analysed for their hop bitter acid, phenolic acid and polyphenol contents. Based on analytical data, it was evident that the beers had been produced using a range of different raw materials and hopping practices. Principal Components Analysis was used to select a sub-set of 10 beers that contained diverse concentrations of the analysed bitter compounds. These beers were appraised sensorially to determine the impacts of varying hop acid and polyphenolic profiles on perceived bitterness character. Beers high in polyphenol and hop acid contents were perceived as having 'harsh' and 'progressive' bitterness, whilst beers that had evidently been conventionally hopped were 'sharp' and 'instant' in their bitterness. Beers containing light-stable hop products (tetrahydro-iso-α-acids) were perceived as 'diminishing', 'rounded' and 'acidic' in bitterness. The hopping strategy adopted by brewers impacts on the nature, temporal profile and intensity of bitterness perception in beer. PMID:27006233

  18. Risk of invasive cervical cancer after atypical glandular cells in cervical screening: nationwide cohort study

    PubMed Central

    Andrae, Bengt; Sundström, Karin; Ström, Peter; Ploner, Alexander; Elfström, K Miriam; Arnheim-Dahlström, Lisen; Dillner, Joakim; Sparén, Pär

    2016-01-01

    Objectives To investigate the risks of invasive cervical cancer after detection of atypical glandular cells (AGC) during cervical screening. Design Nationwide population based cohort study. Setting Cancer and population registries in Sweden. Participants 3 054 328 women living in Sweden at any time between 1 January 1980 and 1 July 2011 who had any record of cervical cytological testing at ages 23-59. Of these, 2 899 968 women had normal cytology results at the first screening record. The first recorded abnormal result was atypical glandular cells (AGC) in 14 625, high grade squamous intraepithelial lesion (HSIL) in 65 633, and low grade squamous intraepithelial lesions (LSIL) in 244 168. Main outcome measures Cumulative incidence of invasive cervical cancer over 15.5 years; proportion of invasive cervical cancer within six months of abnormality (prevalence); crude incidence rates for invasive cervical cancer over 0.5-15.5 years of follow-up; incidence rate ratios compared with women with normal cytology, estimated with Poisson regression adjusted for age and stratified by histopathology of cancer; distribution of clinical assessment within six months after the abnormality. Results The prevalence of cervical cancer was 1.4% for women with AGC, which was lower than for women with HSIL (2.5%) but higher than for women with LSIL (0.2%); adenocarcinoma accounted for 73.2% of the prevalent cases associated with AGC. The incidence rate of invasive cervical cancer after AGC was significantly higher than for women with normal results on cytology for up to 15.5 years and higher than HSIL and LSIL for up to 6.5 years. The incidence rate of adenocarcinoma was 61 times higher than for women with normal results on cytology in the first screening round after AGC, and remained nine times higher for up to 15.5 years. Incidence and prevalence of invasive cervical cancer was highest when AGC was found at ages 30-39. Only 54% of women with AGC underwent histology assessment

  19. SU-E-I-04: A Mammography Phantom to Measure Mean Glandular Dose and Image Quality

    SciTech Connect

    Lopez-Pineda, E; Ruiz-Trejo, C; E, Brandan M

    2014-06-01

    Purpose: To evaluate mean glandular dose (MGD) and image quality in a selection of mammography systems using a novel phantom based on thermoluminescent dosemeters and the ACR wax insert. Methods: The phantom consists of two acrylic, 19 cm diameter, 4.5 cm thick, semicircular modules, used in sequence. The image quality module contains the ACR insert and is used to obtain a quality control image under automatic exposure conditions. The dosimetric module carries 15 TLD-100 chips, some under Al foils, to determine air kerma and half-value-layer. TL readings take place at our laboratory under controlled conditions. Calibration was performed using an ionization chamber and a Senographe 2000D unit for a variety of beam qualities, from 24 to 40 kV, Mo and Rh anodes and filters. Phantom MGD values agree, on the average, within 3% with ionization chamber data, and their precision is better than 10% (k=1). Results: MGD and image quality have been evaluated in a selection of mammography units currently used in Mexican health services. The sample includes analogic (screen/film), flexible digital (CR), and full-field digital image receptors. The highest MDG are associated to the CR technology. The most common image quality failure is due to artifacts (dust, intensifying screen scratches, and processor marks for film/screen, laser reader defects for CR). Conclusion: The developed phantom permits the MGD measurement without the need of a calibrated ionization chamber at the mammography site and can be used by a technician without the presence of a medical physicist. The results indicate the urgent need to establish quality control programs for mammography.

  20. Average glandular dose in digital mammography and digital breast tomosynthesis: comparison of phantom and patient data

    NASA Astrophysics Data System (ADS)

    Bouwman, R. W.; van Engen, R. E.; Young, K. C.; den Heeten, G. J.; Broeders, M. J. M.; Schopphoven, S.; Jeukens, C. R. L. P. N.; Veldkamp, W. J. H.; Dance, D. R.

    2015-10-01

    For the evaluation of the average glandular dose (AGD) in digital mammography (DM) and digital breast tomosynthesis (DBT) phantoms simulating standard model breasts are used. These phantoms consist of slabs of polymethyl methacrylate (PMMA) or a combination of PMMA and polyethylene (PE). In the last decades the automatic exposure control (AEC) increased in complexity and became more sensitive to (local) differences in breast composition. The question is how well the AGD estimated using these simple dosimetry phantoms agrees with the average patient AGD. In this study the AGDs for both dosimetry phantoms and for patients have been evaluated for 5 different x-ray systems in DM and DBT modes. It was found that the ratios between patient and phantom AGD did not differ considerably using both dosimetry phantoms. These ratios averaged over all breast thicknesses were 1.14 and 1.15 for the PMMA and PMMA-PE dosimetry phantoms respectively in DM mode and 1.00 and 1.02 in the DBT mode. These ratios were deemed to be sufficiently close to unity to be suitable for dosimetry evaluation in quality control procedures. However care should be taken when comparing systems for DM and DBT since depending on the AEC operation, ratios for particular breast thicknesses may differ substantially (0.83-1.96). Although the predictions of both phantoms are similar we advise the use of PMMA  +  PE slabs for both DM and DBT to harmonize dosimetry protocols and avoid any potential issues with the use of spacers with the PMMA phantoms.

  1. Normalized mean glandular dose computation from mammography using GATE: a validation study

    NASA Astrophysics Data System (ADS)

    Myronakis, Marios E.; Zvelebil, Marketa; Darambara, Dimitra G.

    2013-04-01

    Mean glandular dose (MGD) is the figure of merit to assess breast dose after a mammographic acquisition. The use of normalized MGD obtained from Monte Carlo computations with measured incident air kerma determines the MGD delivered to patients. The Geant4 Application for Tomographic Emission (GATE) toolkit is a modern Monte Carlo application specifically designed for medical imaging systems modelling. Although there is an increasing number of publications using GATE worldwide for a wide range of medical imaging and therapeutic applications, there is currently no means to obtain normalized MGD. In this work, the GATE toolkit is extended, through the development of two new modules, to provide normalized MGD information for compressed breast phantoms based on simple geometries. The normalized MGD values were validated against published work and provided results at half value layers lower than 0.3 and greater than 0.6 mmAl. In addition, the skin thickness and composition were considered. Normalized MGD was computed after substitution of the adipose layer surrounding the standard breast phantom with skin tissue and the relative difference is reported. Spectrum generation was facilitated by further development of previously published work by other authors. Validation of the new GATE extension showed good agreement with published data and can be used to assess breast dose from mammographic as well as more complex x-ray imaging techniques. Changing skin thickness and composition revealed substantial changes in normalized MGD specifically for compressed breast thickness different than 5 cm and a possible revision of the structure of the standard breast model may be necessary.

  2. Average glandular dose in digital mammography and digital breast tomosynthesis: comparison of phantom and patient data.

    PubMed

    Bouwman, R W; van Engen, R E; Young, K C; den Heeten, G J; Broeders, M J M; Schopphoven, S; Jeukens, C R L P N; Veldkamp, W J H; Dance, D R

    2015-10-21

    For the evaluation of the average glandular dose (AGD) in digital mammography (DM) and digital breast tomosynthesis (DBT) phantoms simulating standard model breasts are used. These phantoms consist of slabs of polymethyl methacrylate (PMMA) or a combination of PMMA and polyethylene (PE). In the last decades the automatic exposure control (AEC) increased in complexity and became more sensitive to (local) differences in breast composition. The question is how well the AGD estimated using these simple dosimetry phantoms agrees with the average patient AGD. In this study the AGDs for both dosimetry phantoms and for patients have been evaluated for 5 different x-ray systems in DM and DBT modes. It was found that the ratios between patient and phantom AGD did not differ considerably using both dosimetry phantoms. These ratios averaged over all breast thicknesses were 1.14 and 1.15 for the PMMA and PMMA-PE dosimetry phantoms respectively in DM mode and 1.00 and 1.02 in the DBT mode. These ratios were deemed to be sufficiently close to unity to be suitable for dosimetry evaluation in quality control procedures. However care should be taken when comparing systems for DM and DBT since depending on the AEC operation, ratios for particular breast thicknesses may differ substantially (0.83-1.96). Although the predictions of both phantoms are similar we advise the use of PMMA  +  PE slabs for both DM and DBT to harmonize dosimetry protocols and avoid any potential issues with the use of spacers with the PMMA phantoms. PMID:26407015

  3. Predominant Glandular Cholinergic Dysautonomia in Patients with Primary Sjögren’s Syndrome

    PubMed Central

    Imrich, Richard; Alevizos, Ilias; Bebris, Lolita; Goldstein, David S.; Holmes, Courtney S.; Illei, Gabor G.; Nikolov, Nikolay P.

    2015-01-01

    Objectives The autonomic nervous system (ANS) modulates exocrine gland function. Available data show poor correlation between the degree of exocrine gland function and destruction in primary Sjögren’s syndrome (pSS) suggesting other mechanisms, such as autonomic dysfunction may be important in these patients. We performed a comprehensive analysis of sympathoneural and sympathetic cholinergic function in well-characterized patients with pSS. Methods 21 pSS patients (mean±SE age 44±3 years) and in 13 healthy controls (51±2 years) were assessed during orthostasis and intravenous injection of edrophonium (10 mg). The postganglionic sympathetic cholinergic system was evaluated by assessing sweat production by the quantitative sudomotor axon reflex test (QSART). Gastric empting testing assessed the gastro-intestinal ANS in pSS patients. Results Velocity index and acceleration index were significantly higher (p<0.05) in pSS compared to controls before and during the orthostatic and edrophonium tests. Other hemodynamic and neurochemical parameters did not differ between pSS patients and controls during the orthostasis and edrophonium test, however, edrophonium-induced saliva increment was lower in pSS (p=0.002). Abnormally low sweat production was found in four (N=4) pSS patients but in none of the controls in the QSART. Gastric empting was delayed in 53 % of pSS patients. Conclusion We observed subtle differences in several ANS domains, including gastrointestinal and sympathocholinergic system suggesting a complex ANS dysfunction in pSS. The impact was the largest on the exocrine glands with subtle differences in the cardiac parasympathetic function independent of glandular inflammation and atrophy, suggesting an alternative pathogenesis mechanism of the disease in pSS. PMID:25622919

  4. Normalized mean glandular dose computation from mammography using GATE: a validation study.

    PubMed

    Myronakis, Marios E; Zvelebil, Marketa; Darambara, Dimitra G

    2013-04-01

    Mean glandular dose (MGD) is the figure of merit to assess breast dose after a mammographic acquisition. The use of normalized MGD obtained from Monte Carlo computations with measured incident air kerma determines the MGD delivered to patients. The Geant4 Application for Tomographic Emission (GATE) toolkit is a modern Monte Carlo application specifically designed for medical imaging systems modelling. Although there is an increasing number of publications using GATE worldwide for a wide range of medical imaging and therapeutic applications, there is currently no means to obtain normalized MGD. In this work, the GATE toolkit is extended, through the development of two new modules, to provide normalized MGD information for compressed breast phantoms based on simple geometries. The normalized MGD values were validated against published work and provided results at half value layers lower than 0.3 and greater than 0.6 mmAl. In addition, the skin thickness and composition were considered. Normalized MGD was computed after substitution of the adipose layer surrounding the standard breast phantom with skin tissue and the relative difference is reported. Spectrum generation was facilitated by further development of previously published work by other authors. Validation of the new GATE extension showed good agreement with published data and can be used to assess breast dose from mammographic as well as more complex x-ray imaging techniques. Changing skin thickness and composition revealed substantial changes in normalized MGD specifically for compressed breast thickness different than 5 cm and a possible revision of the structure of the standard breast model may be necessary. PMID:23475310

  5. Glandular odontogenic cyst – Literature review and report of a paediatric case

    PubMed Central

    Faisal, Mohammad; Ahmad, Syed Ansar; Ansari, Uzma

    2015-01-01

    Glandular odontogenic cyst (GOC) is an extremely rare lesion occurring in the jawbones. The present paper is a review of 181 cases of GOCs reported in English literature, since it was first reported by Padayache and Van Wyk in 1987. Mandible was involved in 130 cases and maxilla in 51 cases. Anterior mandible was the most common area of involvement. Radiographic appearance was that of a unilocular radiolucency in 98 of 176 reported cases. Rest presented as multilocular radiolucency. Cortical expansion was observed in 136 of the 180 reported cases while cortex breach or perforation was seen in 81 cases. The treatment of choice was that of minor procedures that included enucleation with or without curettage, peripheral ostectomy, cryotherapy, etc. in 157 of the total 177 reported cases. Marginal jaw resection, segmental mandibulectomy etc. was reported in 20 cases. Although minor surgical procedures were the treatment of choice in most studies, two major studies of Kaplan et al. and Fowler et al. involving 111 and 46 cases, recorded a recurrence rate of 35.9 and 19.6%, respectively. The age range was between 11 and 82 years. The respective mean age of patients in the above mentioned studies was 45.7 for Kaplan's and 51 years for Fowler's whereas in our study, the mean age was 45.9 years. Very rarely does GOC presents itself in a paediatric patient. The paper also reports a case of an 11-year-old child whose histopathogy came out to be a case of a GOC. PMID:26587384

  6. Fast frequency hopping codes applied to SAC optical CDMA network

    NASA Astrophysics Data System (ADS)

    Tseng, Shin-Pin

    2015-06-01

    This study designed a fast frequency hopping (FFH) code family suitable for application in spectral-amplitude-coding (SAC) optical code-division multiple-access (CDMA) networks. The FFH code family can effectively suppress the effects of multiuser interference and had its origin in the frequency hopping code family. Additional codes were developed as secure codewords for enhancing the security of the network. In considering the system cost and flexibility, simple optical encoders/decoders using fiber Bragg gratings (FBGs) and a set of optical securers using two arrayed-waveguide grating (AWG) demultiplexers (DeMUXs) were also constructed. Based on a Gaussian approximation, expressions for evaluating the bit error rate (BER) and spectral efficiency (SE) of SAC optical CDMA networks are presented. The results indicated that the proposed SAC optical CDMA network exhibited favorable performance.

  7. Nanowire-based thermoelectric ratchet in the hopping regime

    NASA Astrophysics Data System (ADS)

    Bosisio, Riccardo; Fleury, Geneviève; Pichard, Jean-Louis; Gorini, Cosimo

    2016-04-01

    We study a thermoelectric ratchet consisting of an array of disordered nanowires arranged in parallel on top of an insulating substrate and contacted asymmetrically to two electrodes. Transport is investigated in the Mott hopping regime, when localized electrons can propagate through the nanowires via thermally assisted hops. When the electronic temperature in the nanowires is different from the phononic one in the substrate, we show that a finite electrical current is generated even in the absence of driving forces between the electrodes. We discuss the device performance both as an energy harvester, when an excess heat from the substrate is converted into useful power, and as a refrigerator, when an external power is supplied to cool down the substrate.

  8. Dielectric relaxation and hopping conduction in reduced graphite oxide

    NASA Astrophysics Data System (ADS)

    Wei, Guidan; Yu, Ji; Gu, Min; Tang, Tong B.

    2016-06-01

    Graphite oxide reduced by sodium borohydride was characterised and its electrical conduction investigated with impedance spectroscopy. Thermal dependence of electrical modulus (instead of permittivity, its inverse) was calculated from complex impedance spectra, an approach that prevents any peak in dielectric loss (imaginary component) from being swarmed by large dc conductivity. Two loss peaks appeared at each tested frequency, in a sample of either degree of reduction. The set of weaker peak should arise from the relaxation of some polar bonds, as proposed earlier by us. The stronger loss peaks may correspond to the hopping of conduction electrons; variable range hopping is also consistent with the observed thermal dependence of conductivity. However, nearer ambient temperature there is a change in mechanism, to band transport, with an activation energy of fairly similar values as derived from both loss peaks and conductivity.

  9. Mixed quantum-classical equilibrium in global flux surface hopping

    SciTech Connect

    Sifain, Andrew E.; Wang, Linjun; Prezhdo, Oleg V.

    2015-06-14

    Global flux surface hopping (GFSH) generalizes fewest switches surface hopping (FSSH)—one of the most popular approaches to nonadiabatic molecular dynamics—for processes exhibiting superexchange. We show that GFSH satisfies detailed balance and leads to thermodynamic equilibrium with accuracy similar to FSSH. This feature is particularly important when studying electron-vibrational relaxation and phonon-assisted transport. By studying the dynamics in a three-level quantum system coupled to a classical atom in contact with a classical bath, we demonstrate that both FSSH and GFSH achieve the Boltzmann state populations. Thermal equilibrium is attained significantly faster with GFSH, since it accurately represents the superexchange process. GFSH converges closer to the Boltzmann averages than FSSH and exhibits significantly smaller statistical errors.

  10. Trajectory surface-hopping study of methane photodissociation dynamics

    NASA Astrophysics Data System (ADS)

    Lodriguito, Maricris D.; Lendvay, György; Schatz, George C.

    2009-12-01

    We use the fewest switches nonadiabatic trajectory surface hopping approach to study the photodissociation of methane on its lowest singlet excited state potential surface (1 T12) at 122 nm, with emphasis on product state branching and energy partitioning. The trajectories and couplings are based on CASSCF(8,9) calculations with an aug-cc-pvdz basis set. We demonstrate that nonadiabatic dynamics is important to describe the dissociation processes. We find that CH3(X˜ A22″)+H and CH2(ã A11)+H2 are the major dissociation channels, as have been observed experimentally. CH3+H is mostly formed by direct dissociation that is accompanied by hopping to the ground state. CH2+H2 can either be formed by hopping to the ground state to give CH2(ã A11)+H2 or by adiabatic dissociation to CH2(b˜ B11)+H2. In the latter case, the CH2(b˜ B11) can then undergo internal conversion to the ground singlet state by Renner-Teller induced hopping. Less important dissociation mechanisms lead to CH2+H+H and to CH+H2+H. Intersystem crossing effects, which are not included, do not seem essential to describe the experimentally observed branching behavior. About 5% of trajectories involve a roaming atom mechanism which can eventually lead to formation of products in any of the dissociation channels. Branching fractions to give H and H2 are in good agreement with experiment, and the H atom translational energy distribution shows bimodal character which also matches observations.

  11. HPLC Analysis of alpha and beta Acids in Hops

    SciTech Connect

    Danenhower, Travis; Force, Leyna; Petersen, Kenneth; Betts, Thomas; Baker, Gary A

    2008-01-01

    Early in brewing history, a variety of herbs and spices (such as coriander, rosemary, yarrow, and bog myrtle) were used to flavor beer (1). It is evident, from the Bavarian Purity Law of 1516, that a major shift in beer flavoring occurred around the middle of the second millennium. This law declared that only three ingredients could be used to brew beer: barley, water, and hops (1), thus eliminating other spices from German beer. (The importance of yeast had not yet been uncovered.)

  12. Light-induced hopping conductivity in a transparent oxide

    NASA Astrophysics Data System (ADS)

    Medvedeva, J. E.; Freeman, A. J.; Bertoni, M. I.; Mason, T. O.

    2004-03-01

    Recently, Hayashi et al (K. Hayashi et al), Nature 419, 462 (2002) found a way to convert a transparent oxide into a persistent conductor using UV light. The simplicity of the insulator-conductor conversion (hydrogen annealing followed by UV irradiation) and the resulting drastic change in conductivity (by 10 orders of magnitude) makes this material an extremely attractive starting point for optoelectronic applications. Despite careful experimental studies, no definitive understanding has been reached on the underlying mechanism responsible for this new dramatic effect. Here we demonstrate that ab-initio calculations provide a detailed explanation of the experimental findings and reveal the origin of the light-induced conductivity. We (i) show that the charge transport, associated with photo-excitation of an electron from hydrogen, occurs by electron hopping, (ii) determine the exact paths for the carrier migration and (iii) derive the temperature behavior of the hopping conductivity. We predict the strong dependence of the transport on the particular hopping centers and their spatial arrangement which is confirmed by our measurements, and investigate the possibility of varying the conductivity by proper doping.

  13. Critical appraisal of the fewest switches algorithm for surface hopping.

    PubMed

    Granucci, Giovanni; Persico, Maurizio

    2007-04-01

    In this paper the authors address the problem of internal consistency in trajectory surface hopping methods, i.e., the requirement that the fraction of trajectories running on each electronic state equals the probabilities computed by the electronic time-dependent Schrodinger equation, after averaging over all trajectories. They derive a formula for the hopping probability in Tully's "fewest switches" spirit that would yield a rigorously consistent treatment. They show the relationship of Tully's widely used surface hopping algorithm with the "exact" prescription that cannot be applied when running each trajectory independently. They also bring out the connection of the consistency problem with the coherent propagation of the electronic wave function and the artifacts caused by coherent Rabi-type oscillations of the state probabilities in weak coupling regimes. A real molecule (azobenzene) and two ad hoc models serve as examples to illustrate the above theoretical arguments. Following a proposal by Truhlar's group [Zhu et al., J. Chem. Phys. 121, 7658 (2004) Zhu et al., J. Chem. Theory Comput. 1, 527 (2005)], they apply a decoherence correction to the state probabilities, in conjunction with Tully's algorithm, and they obtain satisfactory results in terms of internal consistency and of agreement with the outcomes of quantum wave packet calculations. PMID:17430023

  14. Variable-Range Hopping through Marginally Localized Phonons

    NASA Astrophysics Data System (ADS)

    Banerjee, Sumilan; Altman, Ehud

    2016-03-01

    We investigate the effect of coupling Anderson localized particles in one dimension to a system of marginally localized phonons having a symmetry protected delocalized mode at zero frequency. This situation is naturally realized for electrons coupled to phonons in a disordered nanowire as well as for ultracold fermions coupled to phonons of a superfluid in a one-dimensional disordered trap. To determine if the coupled system can be many-body localized we analyze the phonon-mediated hopping transport for both the weak and strong coupling regimes. We show that the usual variable-range hopping mechanism involving a low-order phonon process is ineffective at low temperature due to discreteness of the bath at the required energy. Instead, the system thermalizes through a many-body process involving exchange of a diverging number n ∝-log T of phonons in the low temperature limit. This effect leads to a highly singular prefactor to Mott's well-known formula and strongly suppresses the variable range hopping rate. Finally, we comment on possible implications of this physics in higher dimensional electron-phonon coupled systems.

  15. Hip-Hop(e): The Cultural Practice and Critical Pedagogy of International Hip-Hop. Adolescent Cultures, School, and Society. Volume 56

    ERIC Educational Resources Information Center

    Porfilio, Brad J., Ed.; Viola, Michael J., Ed.

    2012-01-01

    Illuminating hip-hop as an important cultural practice and a global social movement, this collaborative project highlights the emancipatory messages and cultural work generated by the organic intellectuals of global hip-hop. Contributors describe the social realities--globalization, migration, poverty, criminalization, and racism--youth are…

  16. Effects of Powdery Mildew Fungicide Programs on Twospotted Spider Mite (Acari: Tetranychidae), Hop Aphid (Homoptera: Aphididae), and Their Natural Enemies in Hop Yards

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Twospotted spider mite, Tetranychus urticae Koch (Acari:Tetranychidae), and hop aphid, Phorodon humuli (Schrank) (Homoptera:Aphidiae), are the most important arthropod pests of hop (Humulus lupulus L.) in the Northern Hemisphere. A potential barrier for greater adoption of conservation biological c...

  17. Hop-Based Energy Aware Routing Algorithm for Wireless Sensor Networks

    NASA Astrophysics Data System (ADS)

    Wang, Jin; Cho, Jinsung; Lee, Sungyoung; Chen, Kwang-Cheng; Lee, Young-Koo

    Energy efficient routing is one of the key design issues to prolong the lifetime of wireless sensor networks (WSNs) since sensor nodes can not be easily re-charged once they are deployed. During routing process, the routes with only few hops or with too many hops are not energy efficient. Hop-based routing algorithms can largely improve the energy efficiency of multi-hop routing in WSNs because they can determine the optimal hop number as well as the corresponding intermediate nodes during multi-hop routing process under medium or high density network. In this paper, we not only focus on studying the relationship between energy consumption and hop number from theoretical point of view but also provide a practical selection criterion of the sub-optimal hop number under practical sensor network so as to minimize the energy consumption. We extend the theoretical deduction of optimal hop number and propose our Hop-based Energy Aware Routing (HEAR) algorithm which is totally distributed and localized. Simulation results show that our HEAR algorithm can reduce the average energy consumption about 10 times compared to the direct transmission algorithm and 2 to 10 times than other algorithms like LEACH and HEED under various network topologies.

  18. A WD40 Repeat Protein from Medicago truncatula Is Necessary for Tissue-Specific Anthocyanin and Proanthocyanidin Biosynthesis But Not for Trichome Development1[W][OA

    PubMed Central

    Pang, Yongzhen; Wenger, Jonathan P.; Saathoff, Katie; Peel, Gregory J.; Wen, Jiangqi; Huhman, David; Allen, Stacy N.; Tang, Yuhong; Cheng, Xiaofei; Tadege, Million; Ratet, Pascal; Mysore, Kirankumar S.; Sumner, Lloyd W.; Marks, M. David; Dixon, Richard A.

    2009-01-01

    WD40 repeat proteins regulate biosynthesis of anthocyanins, proanthocyanidins (PAs), and mucilage in the seed and the development of trichomes and root hairs. We have cloned and characterized a WD40 repeat protein gene from Medicago truncatula (MtWD40-1) via a retrotransposon-tagging approach. Deficiency of MtWD40-1 expression blocks accumulation of mucilage and a range of phenolic compounds, including PAs, epicatechin, other flavonoids, and benzoic acids, in the seed, reduces epicatechin levels without corresponding effects on other flavonoids in flowers, reduces isoflavone levels in roots, but does not impair trichome or root hair development. MtWD40-1 is expressed constitutively, with highest expression in the seed coat, where its transcript profile temporally parallels those of PA biosynthetic genes. Transcript profile analysis revealed that many genes of flavonoid biosynthesis were down-regulated in a tissue-specific manner in M. truncatula lines harboring retrotransposon insertions in the MtWD40-1 gene. MtWD40-1 complemented the anthocyanin, PA, and trichome phenotypes of the Arabidopsis (Arabidopsis thaliana) transparent testa glabrous1 mutant. We discuss the function of MtWD40-1 in natural product formation in M. truncatula and the potential use of the gene for engineering PAs in the forage legume alfalfa (Medicago sativa). PMID:19710231

  19. A WD40 repeat protein from Medicago truncatula is necessary for tissue-specific anthocyanin and proanthocyanidin biosynthesis but not for trichome development.

    PubMed

    Pang, Yongzhen; Wenger, Jonathan P; Saathoff, Katie; Peel, Gregory J; Wen, Jiangqi; Huhman, David; Allen, Stacy N; Tang, Yuhong; Cheng, Xiaofei; Tadege, Million; Ratet, Pascal; Mysore, Kirankumar S; Sumner, Lloyd W; Marks, M David; Dixon, Richard A

    2009-11-01

    WD40 repeat proteins regulate biosynthesis of anthocyanins, proanthocyanidins (PAs), and mucilage in the seed and the development of trichomes and root hairs. We have cloned and characterized a WD40 repeat protein gene from Medicago truncatula (MtWD40-1) via a retrotransposon-tagging approach. Deficiency of MtWD40-1 expression blocks accumulation of mucilage and a range of phenolic compounds, including PAs, epicatechin, other flavonoids, and benzoic acids, in the seed, reduces epicatechin levels without corresponding effects on other flavonoids in flowers, reduces isoflavone levels in roots, but does not impair trichome or root hair development. MtWD40-1 is expressed constitutively, with highest expression in the seed coat, where its transcript profile temporally parallels those of PA biosynthetic genes. Transcript profile analysis revealed that many genes of flavonoid biosynthesis were down-regulated in a tissue-specific manner in M. truncatula lines harboring retrotransposon insertions in the MtWD40-1 gene. MtWD40-1 complemented the anthocyanin, PA, and trichome phenotypes of the Arabidopsis (Arabidopsis thaliana) transparent testa glabrous1 mutant. We discuss the function of MtWD40-1 in natural product formation in M. truncatula and the potential use of the gene for engineering PAs in the forage legume alfalfa (Medicago sativa). PMID:19710231

  20. Induced resistance in groundnut by jasmonic acid and salicylic acid through alteration of trichome density and oviposition by Helicoverpa armigera (Lepidoptera: Noctuidae)

    PubMed Central

    War, Abdul Rashid; Hussain, Barkat; Sharma, Hari C.

    2013-01-01

    Jasmonic acid (JA) and salicylic acid (SA) are important phytohormones involved in plant resistance against insect herbivory and pathogen infection. Application of JA and SA induces several defensive traits in plants. Here we investigated the effect of JA and SA on trichome density in five groundnut genotypes [ICGV 86699, ICGV 86031, ICG 2271, ICG 1697 (resistant) and JL 24 (susceptible)]. The effect of JA- and SA-induced resistance on the oviposition behaviour of Helicoverpa armigera on different groundnut genotypes was also studied. Pre-treatment with JA increased numbers of trichomes in the insect-resistant genotypes, ICGV 86699, ICGV 86031, ICG 2271, and ICG 1697. The induction was greater at 10 days after treatment. Jasmonic acid- and SA-treated plants showed a substantial effect on the oviposition behaviour of H. armigera. Jasmonic acid application and herbivory reduced the number of eggs laid by H. armigera in all the groundnut genotypes tested. However, a greater reduction was recorded on plants pre-treated with JA. More egg laying was recorded in JL 24 in all the treatments as compared to the insect-resistant genotypes. These results suggested that pre-treatment with JA increased trichome density in groundnut plants, which conferred antixenosis for oviposition by H. armigera.

  1. Multi-Hop Link Capacity of Multi-Route Multi-Hop MRC Diversity for a Virtual Cellular Network

    NASA Astrophysics Data System (ADS)

    Daou, Imane; Kudoh, Eisuke; Adachi, Fumiyuki

    In virtual cellular network (VCN), proposed for high-speed mobile communications, the signal transmitted from a mobile terminal is received by some wireless ports distributed in each virtual cell and relayed to the central port that acts as a gateway to the core network. In this paper, we apply the multi-route MHMRC diversity in order to decrease the transmit power and increase the multi-hop link capacity. The transmit power, the interference power and the link capacity are evaluated for DS-CDMA multi-hop VCN by computer simulation. The multi-route MHMRC diversity can be applied to not only DS-CDMA but also other access schemes (i. e. MC-CDMA, OFDM, etc.).

  2. ‘And then there were three’: highly efficient uptake of potassium by foliar trichomes of epiphytic bromeliads

    PubMed Central

    Winkler, Uwe; Zotz, Gerhard

    2010-01-01

    Background and Aims Vascular epiphytes have to acquire nutrients from atmospheric wash out, stem-flow, canopy soils and trapped litter. Physiological studies on the adaptations to nutrient acquisition and plant utilization of nutrients have focused on phosphorus and nitrogen; potassium, as a third highly abundant nutrient element, has received minor attention. In the present study, potassium uptake kinetics by leaves, within-plant distribution and nutrient accumulation were analysed to gain an improved understanding of physiological adaptations to non-terrestrial nutrient supply of plants. Methods Radioactively labelled 86RbCl was used as an analogue to study uptake kinetics of potassium absorbed from tanks of epiphytes, its plant distribution and the correlation between uptake efficiency and abundance of trichomes, functioning as uptake organs of leaves. Potassium in leaves was additionally analysed by atomic absorption spectroscopy to assess plant responses to potassium deficiency. Key Results Labelled rubidium was taken up from tanks over a wide range of concentrations, 0·01–90 mm, which was achieved by two uptake systems. In four tank epiphytes, the high-affinity transporters had average Km values of 41·2 µm, and the low-affinity transporters average Km values of 44·8 mm. Further analysis in Vriesea splenriet showed that high-affinity uptake of rubidium was an ATP-dependent process, while low-affinity uptake was mediated by a K+-channel. The kinetic properties of both types of transporters are comparable with those of potassium transporters in roots of terrestrial plants. Specific differences in uptake velocities of epiphytes are correlated with the abundance of trichomes on their leaf surfaces. The main sinks for potassium were fully grown leaves. These leaves thus function as internal potassium sources, which allow growth to be maintained during periods of low external potassium availability. Conclusions Vascular epiphytes possess effective mechanisms

  3. Polaron hopping in olivine phosphates studied by nuclear resonant scattering

    NASA Astrophysics Data System (ADS)

    Tracy, Sally June

    Valence fluctuations of Fe2+ and Fe3+ were studied in a solid solution of LixFePO4 by nuclear resonant forward scattering of synchrotron x rays while the sample was heated in a diamond-anvil pressure cell. The spectra acquired at different temperatures and pressures were analyzed for the frequencies of valence changes using the Blume-Tjon model of a system with a fluctuating Hamiltonian. These frequencies were analyzed to obtain activation energies and an activation volume for polaron hopping. There was a large suppression of hopping frequency with pressure, giving an anomalously large activation volume. This large, positive value is typical of ion diffusion, which indicates correlated motions of polarons, and Li+ ions that alter the dynamics of both. In a parallel study of NaxFePO4, the interplay between sodium ordering and electron mobility was investigated using a combination of synchrotron x-ray diffraction and nuclear resonant scattering. Conventional Mossbauer spectra were collected while the sample was heated in a resistive furnace. An analysis of the temperature evolution of the spectral shapes was used to identify the onset of fast electron hopping and determine the polaron hopping rate. Synchrotron x-ray diffraction measurements were carried out in the same temperature range. Reitveld analysis of the diffraction patterns was used to determine the temperature of sodium redistribution on the lattice. The diffraction analysis also provides new information about the phase stability of the system. The temperature evolution of the iron site occupancies from the Mossbauer measurements, combined with the synchrotron diffraction results give strong evidence for a relationship between the onset of fast electron dynamics and the redistribution of sodium in the lattice. Measurements of activation barriers for polaron hopping gave fundamental insights about the correlation between electronic carriers and mobile ions. This work established that polaron-ion interactions

  4. Imbalance in expression of hop (Humulus lupulus) chalcone synthase H1 and its regulators during hop stunt viroid pathogenesis.

    PubMed

    Füssy, Zoltán; Patzak, Josef; Stehlík, Jan; Matoušek, Jaroslav

    2013-05-01

    Viroid-derived small RNAs generated during hop stunt viroid (HSVd) pathogenesis may induce the symptoms found in the hop cultivar "Admiral", including observed shifts in phenylpropanoid metabolites and changes in petiole coloration. Using quantitative RT-PCR, we examined hop lupulin gland-specific genes that have been shown to be involved in phenylpropanoid metabolism, for altered expression in response to infection with two HSVd isolates, HSVd-g and CPFVd. Most notably, the expression of a gene encoding a key enzyme for phenylpropanoid synthesis, naringenin-chalcone synthase H1 (chs_H1), decreased up to 40-fold in infected samples. In addition, a marked decrease in the expression of HlbHLH2 and an increase in the expression of HlMyb3 were observed. These two genes encode transcription factors that form a ternary complex with HlWDR1 for chs_H1 promoter activation. In a transient expression assay, a decrease in the ternary complex potential to activate the chs_H1 promoter was observed upon the decrease of HlbHLH2 expression. In addition, targeting of the chs_H1 transcript by vd-sRNAs may contribute to these expression changes. Our data show that HSVd infection causes a significant imbalance in the expression of phenylpropanoid metabolite-affecting genes via a complex mechanism, possibly involving regulatory disorders and direct targeting by vd-sRNA. PMID:23395540

  5. Image quality, threshold contrast and mean glandular dose in CR mammography

    NASA Astrophysics Data System (ADS)

    Jakubiak, R. R.; Gamba, H. R.; Neves, E. B.; Peixoto, J. E.

    2013-09-01

    In many countries, computed radiography (CR) systems represent the majority of equipment used in digital mammography. This study presents a method for optimizing image quality and dose in CR mammography of patients with breast thicknesses between 45 and 75 mm. Initially, clinical images of 67 patients (group 1) were analyzed by three experienced radiologists, reporting about anatomical structures, noise and contrast in low and high pixel value areas, and image sharpness and contrast. Exposure parameters (kV, mAs and target/filter combination) used in the examinations of these patients were reproduced to determine the contrast-to-noise ratio (CNR) and mean glandular dose (MGD). The parameters were also used to radiograph a CDMAM (version 3.4) phantom (Artinis Medical Systems, The Netherlands) for image threshold contrast evaluation. After that, different breast thicknesses were simulated with polymethylmethacrylate layers and various sets of exposure parameters were used in order to determine optimal radiographic parameters. For each simulated breast thickness, optimal beam quality was defined as giving a target CNR to reach the threshold contrast of CDMAM images for acceptable MGD. These results were used for adjustments in the automatic exposure control (AEC) by the maintenance team. Using optimized exposure parameters, clinical images of 63 patients (group 2) were evaluated as described above. Threshold contrast, CNR and MGD for such exposure parameters were also determined. Results showed that the proposed optimization method was effective for all breast thicknesses studied in phantoms. The best result was found for breasts of 75 mm. While in group 1 there was no detection of the 0.1 mm critical diameter detail with threshold contrast below 23%, after the optimization, detection occurred in 47.6% of the images. There was also an average MGD reduction of 7.5%. The clinical image quality criteria were attended in 91.7% for all breast thicknesses evaluated in both

  6. Image quality, threshold contrast and mean glandular dose in CR mammography.

    PubMed

    Jakubiak, R R; Gamba, H R; Neves, E B; Peixoto, J E

    2013-09-21

    In many countries, computed radiography (CR) systems represent the majority of equipment used in digital mammography. This study presents a method for optimizing image quality and dose in CR mammography of patients with breast thicknesses between 45 and 75 mm. Initially, clinical images of 67 patients (group 1) were analyzed by three experienced radiologists, reporting about anatomical structures, noise and contrast in low and high pixel value areas, and image sharpness and contrast. Exposure parameters (kV, mAs and target/filter combination) used in the examinations of these patients were reproduced to determine the contrast-to-noise ratio (CNR) and mean glandular dose (MGD). The parameters were also used to radiograph a CDMAM (version 3.4) phantom (Artinis Medical Systems, The Netherlands) for image threshold contrast evaluation. After that, different breast thicknesses were simulated with polymethylmethacrylate layers and various sets of exposure parameters were used in order to determine optimal radiographic parameters. For each simulated breast thickness, optimal beam quality was defined as giving a target CNR to reach the threshold contrast of CDMAM images for acceptable MGD. These results were used for adjustments in the automatic exposure control (AEC) by the maintenance team. Using optimized exposure parameters, clinical images of 63 patients (group 2) were evaluated as described above. Threshold contrast, CNR and MGD for such exposure parameters were also determined. Results showed that the proposed optimization method was effective for all breast thicknesses studied in phantoms. The best result was found for breasts of 75 mm. While in group 1 there was no detection of the 0.1 mm critical diameter detail with threshold contrast below 23%, after the optimization, detection occurred in 47.6% of the images. There was also an average MGD reduction of 7.5%. The clinical image quality criteria were attended in 91.7% for all breast thicknesses evaluated in

  7. Glandular neoplasms of the urachus: a report of 55 cases emphasizing mucinous cystic tumors with proposed classification.

    PubMed

    Amin, Mahul B; Smith, Steven C; Eble, John N; Rao, Priya; Choi, William W L; Tamboli, Pheroze; Young, Robert H

    2014-08-01

    Published experience remains limited for glandular neoplasms of the urachus, especially mucinous cystic tumors. We reviewed 55 glandular urachal neoplasms to evaluate their clinical features and histopathologic spectrum and to devise a classification system for the mucinous cystic forms. Within the 55 cases studied, we observed 2 groups with differing clinical, gross, and histopathologic features. The first group, invasive, noncystic adenocarcinomas (n=24), had clinicopathologic features in accord with the known spectrum of urachal adenocarcinoma (mean age 50 y, female:male ratio 1.7, with recurrence or death from disease in 9/16 cases over a 45 mo mean follow-up). The second group, mucinous cystic tumors (n=31), morphologically resembled mucinous cystic tumors of the ovary and appeared classifiable by the same approach (mean age 47 y, female:male ratio 1.4) and included mucinous cystadenoma (n=4), mucinous cystic tumor of low malignant potential (n=22, including 2 cases with intraepithelial carcinoma), and mucinous cystadenocarcinoma with microscopic (n=4) or frank invasion (n=1). Follow-up information was available for 13 patients with mucinous cystic tumors (mean 41 mo); we observed no local recurrence or distant metastasis. This experience suggests that there is a distinct group of glandular, cystic tumors of the urachus that is classifiable in a manner similar to ovarian neoplasms and that has a favorable prognosis after complete excision. As with cystic neoplasms of other organs, rigorous sampling is recommended to identify potentially small foci of carcinoma that could be missed by inadequate sampling. Accordingly, classification based on methods other than complete surgical excision may be hazardous. PMID:25025366

  8. Fast proton hopping detection in ice I{sub h} by quasi-elastic neutron scattering.

    SciTech Connect

    Presiado, I.; Lal, J.; Mamontov, E.; Kolesnikov, A. I.; Huppert, D.

    2011-01-01

    Quasi-elastic neutron scattering was employed on samples of HCl-doped polycrystalline ice I{sub h}. The analysis of the scattering signal provides the excess proton hopping time, {tau}{sub hop}, in the temperature range of 140-195 K. The hopping time strongly depends on the temperature of the sample, and the activation energy of a hopping step is 17 kJ/mol. The values of {tau}{sub hop} of the current experiment are in good agreement with calculated values derived from previous photochemical experiments, in which we found that the proton hopping time at T > 242 K is on the order of 200 fs, roughly 10 times shorter than in liquid water at room temperature.

  9. Fast Proton Hopping Detection in Ice Ih by Quasi-Elastic Neutron Scattering

    SciTech Connect

    Presiado, Itay; Lal, Jyotsana; Mamontov, Eugene; Kolesnikov, Alexander I; Huppert, Dan I

    2011-01-01

    Quasi-elastic neutron scattering was employed on samples of HCl-doped polycrystalline ice I{sub h}. The analysis of the scattering signal provides the excess proton hopping time, {tau}{sub hop}, in the temperature range of 140-195 K. The hopping time strongly depends on the temperature of the sample, and the activation energy of a hopping step is 17 kJ/mol. The values of {tau}{sub hop} of the current experiment are in good agreement with calculated values derived from previous photochemical experiments,(1) in which we found that the proton hopping time at T > 242 K is on the order of 200 fs, roughly 10 times shorter than in liquid water at room temperature.

  10. Effect of heat shock on the chilling sensitivity of trichomes and petioles of African violet (Saintpaulia ionantha).

    PubMed

    Saltveit, Mikal E.; Hepler, Peter K.

    2004-05-01

    Chilling at 6 degrees C caused an immediate cessation of protoplasmic streaming in trichomes from African violets (Saintpaulia ionantha), and a slower aggregation of chloroplasts in the cells. Streaming slowly recovered upon warming to 20 degrees C, reaching fairly stable rates after 4, 15, 25 and 35 min for tissue chilled for 2 min and for 2, 14 and 24 h, respectively. The rate of ion leakage from excised petioles into an isotonic 0.2 M mannitol solution increased after 12 h of chilling and reached a maximum after 3 days of chilling. A heat shock at 45 degrees C for 6 min reduced chilling-induced rates of ion leakage from excised 1-cm petiole segments by over 50%, namely to levels near that from non-chilled control tissue. Heat-shock treatments themselves had no effect on the rate of ion leakage from non-chilled petiole segments. Protoplasmic streaming was stopped by 1 min of heat shock at 45 degrees C, but slowly recovered to normal levels after about 30 min Chloroplasts aggregation was prevented by a 1 or 2 min 45 degrees C heat-shock treatment administered 1.5 h before chilling, but heat-shock treatments up to 6 min only slightly delayed the reduction in protoplasmic streaming caused by chilling. Tradescantia virginiana did not exhibit symptoms associated with chilling injury in sensitive species (i.e. cessation of protoplasmic streaming in stamen hairs and increased ion leakage from leaf tissue). PMID:15086815

  11. Trichomes as dangerous lollipops: do lizards also use caterpillar body and frass odor to optimize their foraging?

    PubMed

    Stork, William F J; Weinhold, Alexander; Baldwin, Ian T

    2011-12-01

    When attacked by herbivores, plants produce toxic secondary metabolites that function as direct defenses, as well as indirect defenses that attract and reward predators of the offending herbivores. These indirect defenses include both nutritive rewards such as extra floral nectar, as well as informational rewards, such as the production and release of volatile compounds that betray the location of feeding herbivores to predators. Herbivory of Nicotiana attenuata by the tobacco hornworm (Manduca larvae) alters the volatile profiles of both the plant and larval headspace. Herbivory-elicited specific changes in the volatile profiles are detected by arthropod predators of Manduca larvae. The known predators that perceive volatile cues induced by Manduca herbivory of N. attenuata are insects that target Manduca at early developmental stages, when the larvae are still small; large, late-instar larvae may have outgrown these predation risks. However, here we offer evidence that branched chain aliphatic acids derived from the digestion of plant O-acyl sugars from trichomes may betray Manduca larvae to lizard predators during late developmental stages as well. PMID:22095147

  12. Decoherence and mode hopping in a magnetic tunnel junction based spin torque oscillator.

    PubMed

    Muduli, P K; Heinonen, O G; Akerman, Johan

    2012-05-18

    We discuss the coherence of magnetic oscillations in a magnetic tunnel junction based spin torque oscillator as a function of the external field angle. Time-frequency analysis shows mode hopping between distinct oscillator modes, which arises from linear and nonlinear couplings in the Landau-Lifshitz-Gilbert equation, analogous to mode hopping observed in semiconductor ring lasers. These couplings and, therefore, mode hopping are minimized near the current threshold for the antiparallel alignment of free-layer with reference layer magnetization. Away from the antiparallel alignment, mode hopping limits oscillator coherence. PMID:23003182

  13. Hip-hop as a resource for understanding the urban context

    NASA Astrophysics Data System (ADS)

    Brown, Bryan

    2010-06-01

    This review explores Edmin's "Science education for the hip-hop generation" by documenting how he frames hip-hop as a means to access urban student culture. He argues that hip-hop is more than a mere music genre, but rather a culture that provides young people with ways of connecting to the world. Two primary ideas emerged as central to his work. First, he contends that students develop communal relationships and collective identities based on the common experiences expressed in hip-hop. Second, he identifies how the conscious recognition of institutional oppression serves a central feature in urban schools. Emdin's rich, and personal call for a greater understanding of hip-hop culture provides the text with an unmatched strength. He skillfully uses personal narratives from his own experience as well as quotes and references from hip-hop songs to make the nuances of hip hop transparent to science educators. Conversely, the limitation of this text is found in its unfulfilled promise to provide pragmatic examples of how to engage in a hip-hop based science education. Emdin's work is ultimately valuable as it extends our current knowledge about urban students and hip-hop in meaningful ways.

  14. Optimization of conditions for supercritical fluid extraction of flavonoids from hops (Humulus lupulus L.).

    PubMed

    He, Guo-Qing; Xiong, Hao-Ping; Chen, Qi-He; Ruan, Hui; Wang, Zhao-Yue; Traoré, Lonseny

    2005-10-01

    Waste hops are good sources of flavonoids. Extraction of flavonoids from waste hops (SC-CO(2) extracted hops) using supercritical fluids technology was investigated. Various temperatures, pressures and concentrations of ethanol (modifier) and the ratio (w/w) of solvent to material were tested in this study. The results of single factor and orthogonal experiments showed that at 50 degrees C, 25 MPa, the ratio of solvent to material (50%), ethanol concentration (80%) resulted in maximum extraction yield flavonoids (7.8 mg/g). HPLC-MS analysis of the extracts indicated that flavonoids obtained were xanthohumol, the principal prenylflavonoid in hops. PMID:16187413

  15. Studies of ECCM improvements for frequency-hopping CPFSK systems

    NASA Astrophysics Data System (ADS)

    Lee, J. S.; Miller, L. E.; French, R. H.

    1990-05-01

    The performance of frequency hopping CPFSK modulations (such as used in several Army radio systems) in the presence of worst case partial band noise jamming (WCPBNJ) is derived for both limiter-discriminator and differential detector forms of receiver. The transmitter is assumed to repeat the data L times on different hops, and the receiver combines the L chips for each data symbol in a way to mitigate the effects of the jamming. Hard-decision combining simply makes a binary decision on each chip, then a majority decision on the whole symbol; this limits a jammed chip to one vote. AGC combining weights each analog chip sample in inverse proportion to the received noise power and decides on the basis of the sum of weighted chip samples; jammed chips tend to be weighted less. Analysis and computations show that either form of ECM combining can produce a 27 dB gain against WCPBNJ, and with error-control coding, a 31 to 33 dB gain. Coding alone can give a 28 to 29 dB gain. Soft decoding of hard-decision diversity combining gives 1.4 dB more gain than hard decoding. It is also shown that, due to the spectral attenuation characteristics of the receiver's IF filter, the effects of the transient phase difference between the incoming hopping waveform and the receiver's synthesizer are primarily confined to an interval of duration T + ts + tau, where T is the symbol duration (inverse of IF bandwidth), ts is the synthesizer switching time, and tau is the offset in synchronization between the received signal and the receiver's synthesizer.

  16. Semiclassical quantization of nonadiabatic systems with hopping periodic orbits.

    PubMed

    Fujii, Mikiya; Yamashita, Koichi

    2015-02-21

    We present a semiclassical quantization condition, i.e., quantum-classical correspondence, for steady states of nonadiabatic systems consisting of fast and slow degrees of freedom (DOFs) by extending Gutzwiller's trace formula to a nonadiabatic form. The quantum-classical correspondence indicates that a set of primitive hopping periodic orbits, which are invariant under time evolution in the phase space of the slow DOF, should be quantized. The semiclassical quantization is then applied to a simple nonadiabatic model and accurately reproduces exact quantum energy levels. In addition to the semiclassical quantization condition, we also discuss chaotic dynamics involved in the classical limit of nonadiabatic dynamics. PMID:25701999

  17. Structure and Charge Hopping Dynamics in Green Rust

    SciTech Connect

    Wander, Matthew C; Rosso, Kevin M; Schoonen, Martin A

    2007-08-02

    Green rust is a family of mixed-valent iron phases formed by a number of abiotic and biotic processes under alkaline suboxic conditions. Due to its high Fe2+ content, green rust is a potentially important phase for pollution remediation by serving as a powerful electron donor for reductive transformation. However, mechanisms of oxidation of this material are poorly understood. An essential component of the green rust structure is a mixed-valent brucite-like Fe(OH)2 sheet comprised of a two dimensional network of edge-sharing iron octahedra. Room temperature Mössbauer spectra show a characteristic signature for intermediate valence on the iron atoms in this sheet, indicative of a Fe2+-Fe3+ valence interchange reaction faster than approximately 107 s-1. Using Fe(OH)2 as structural analogue for reduced green rust, we performed Hartree-Fock calculations on periodic slab models and cluster representations to determine the structure and hopping mobility of Fe3+ hole polarons in this material, providing a first principles assessment of the Fe2+-Fe3+ valence interchange reaction rate. The calculations show that among three possible symmetry unique iron-to-iron hops within a sheet, a hop to next-nearest neighbors at an intermediate distance of 5.6 Å is the fastest. The predicted rate is on the order of 1012 s-1 consistent the Mössbauer-based constraint. All other possibilities, including hopping across interlayer spaces, are predicted to be slower than 107 s-1. Collectively, the findings suggest the possibility of hole self-diffusion along sheets as a mechanism for regeneration of lattice Fe2+ sites, consistent with previous experimental observations of edge-inward progressive oxidation of green rust.

  18. Compressive detection of frequency-hopping spread spectrum signals

    NASA Astrophysics Data System (ADS)

    Liu, Feng; Marcellin, Michael W.; Goodman, Nathan A.; Bilgin, Ali

    2013-05-01

    In this paper, compressive detection strategies for FHSS signals are introduced. Rapid switching of the carrier frequency among many channels using a pseudorandom sequence makes detection of FHSS signals challenging. The conventional approach to detect these signals is to rapidly scan small segments of the spectrum sequentially. However, such a scanner has the inherent risk of never overlapping with the transmitted signal depending on factors such as rate of hopping and scanning. In this paper, we propose compressive detection strategies that sample the full spectrum in a compressive manner. Theory and simulations are presented to illustrate the benefits of the proposed framework.

  19. Compressive sensing of frequency-hopping spread spectrum signals

    NASA Astrophysics Data System (ADS)

    Liu, Feng; Kim, Yookyung; Goodman, Nathan A.; Ashok, Amit; Bilgin, Ali

    2012-06-01

    In this paper, compressive sensing strategies for interception of Frequency-Hopping Spread Spectrum (FHSS) signals are introduced. Rapid switching of the carrier among many frequency channels using a pseudorandom sequence (unknown to the eavesdropper) makes FHSS signals dicult to intercept. The conventional approach to intercept FHSS signals necessitates capturing of all frequency channels and, thus, requires the Analog-to-Digital Converters (ADCs) to sample at very high rates. Using the fact that the FHSS signals have sparse instanta- neous spectra, we propose compressive sensing strategies for their interception. The proposed techniques are validated using Gaussian Frequency-Shift Keying (GFSK) modulated FHSS signals as dened by the Bluetooth specication.

  20. Magnetic effect on hopping rate of electrons in organic semiconductors

    NASA Astrophysics Data System (ADS)

    Zhao, Junqing; Wang, Ting; Zhang, Meisheng; Zhang, Ningyu; Pang, Yantao; Li, Luyan; Ji, Yanju; Zhuang, Shidong; Mao, Jinhua; Wang, Huilin

    2013-10-01

    Considering effects of molecular vibration (ω0), hyperfine interaction (J), spin energy split, spin flip, and spin entanglement (η) of electron with nucleus on the hopping rate of electrons in organic semiconductors, we establish a model to calculate organic magnetoresistance (OMAR) within magnetic field B of 1 T. The results show that the effect of spin energy split is minimal, ω0 influences the gradient of OMAR to B in high field, J influences the OMAR in low field, the spin flip shows impact mainly in low field, η affects OMAR throughout the considered magnetic field and turns the high-field OMAR from positive to negative value.

  1. Semiclassical quantization of nonadiabatic systems with hopping periodic orbits

    SciTech Connect

    Fujii, Mikiya Yamashita, Koichi

    2015-02-21

    We present a semiclassical quantization condition, i.e., quantum–classical correspondence, for steady states of nonadiabatic systems consisting of fast and slow degrees of freedom (DOFs) by extending Gutzwiller’s trace formula to a nonadiabatic form. The quantum–classical correspondence indicates that a set of primitive hopping periodic orbits, which are invariant under time evolution in the phase space of the slow DOF, should be quantized. The semiclassical quantization is then applied to a simple nonadiabatic model and accurately reproduces exact quantum energy levels. In addition to the semiclassical quantization condition, we also discuss chaotic dynamics involved in the classical limit of nonadiabatic dynamics.

  2. Serum placental-type alkaline phosphatase activity in women with squamous and glandular malignancies of the reproductive tract.

    PubMed Central

    Ind, T E; Iles, R K; Carter, P G; Lowe, D G; Shepherd, J H; Hudson, C N; Chard, T

    1994-01-01

    AIM--To investigate serum placental-type alkaline phosphatase (PLAP-type) activities in women with squamous and glandular malignancies of the reproductive tract using an immunoradiometric assay. METHODS--PLAP-type immunoreactivity was measured in 180 women with non-ovarian malignancies of the reproductive tract and the values were compared with those from 334 controls. The cases comprised 18 vulval, nine vaginal, 103 cervical, 46 endometrial, and five fallopian tube cancers. RESULTS--Serum PLAP-type activities were no different from controls in patients with squamous cell tumours. Women with adenocarcinoma of the cervix, endometrium, and fallopian tube had increased values: women with endometrial cancer had a median value nearly four times greater than that of controls. There was no direct correlation between PLAP-type activities and stage of disease in patients with endometrial cancer, but values reverted to normal after treatment. CONCLUSIONS--Serum PLAP-type measurements are of no value in the management of patients with squamous cell tumours of the female reproductive tract. Raised activities can, however, be found in glandular tumours, in particular endometrial cancer where serum PLAP-type measurements may be of value in predicting remission. PMID:7829680

  3. Evidence for estrogen-dependent uterine serpin (SERPINA14) expression during estrus in the bovine endometrial glandular epithelium and lumen.

    PubMed

    Ulbrich, Susanne E; Frohlich, Thomas; Schulke, Katy; Englberger, Eva; Waldschmitt, Nadine; Arnold, Georg J; Reichenbach, Horst-Dieter; Reichenbach, Myriam; Wolf, Eckhard; Meyer, Heinrich H D; Bauersachs, Stefan

    2009-10-01

    Uterine secretions have a dominant impact on the environment in which embryo development takes place. The uterine serpins (SERPINA14, previously known as UTMP) are found most abundantly during pregnancy in the uterus of ruminants. Although progesterone is currently assumed to be the major regulator of SERPINA14 expression, our recent study of transcriptome changes in bovine endometrium during the estrous cycle unexpectedly detected a marked upregulation of SERPINA14 mRNA levels at estrus. The present study describes the full-length mRNA sequence, genomic organization, and putative promoter elements of the SERPINA14 gene. The SERPINA14 mRNA abundance was quantified by real-time RT-PCR in intercaruncular endometrium at several time points during the estrous cycle and early pregnancy. Highest levels were found at estrus, followed by a dramatic decrease and a moderate expression during the luteal phase. Transcript levels were higher in pregnant endometrium compared with controls at Day 18. At estrus, immunoreactive protein was localized in deep glandular epithelium, and Western blotting concomitantly showed the 52-kDa form in uterine flushings. SERPINA14 mRNA was significantly upregulated in glandular endometrial cells in vitro after stimulation with estradiol-17beta and progesterone, but not after interferon-tau treatment. Our results clearly demonstrate that SERPINA14 appears distinctly in bovine endometrium during the estrus phase. A supporting role toward providing a well-prepared endometrial environment for passing gametes, especially sperm, is assumed. PMID:19494250

  4. Integration of co-localized glandular morphometry and protein biomarker expression in immunofluorescent images for prostate cancer prognosis

    NASA Astrophysics Data System (ADS)

    Scott, Richard; Khan, Faisal M.; Zeineh, Jack; Donovan, Michael; Fernandez, Gerardo

    2015-03-01

    Immunofluorescent (IF) image analysis of tissue pathology has proven to be extremely valuable and robust in developing prognostic assessments of disease, particularly in prostate cancer. There have been significant advances in the literature in quantitative biomarker expression as well as characterization of glandular architectures in discrete gland rings. However, while biomarker and glandular morphometric features have been combined as separate predictors in multivariate models, there is a lack of integrative features for biomarkers co-localized within specific morphological sub-types; for example the evaluation of androgen receptor (AR) expression within Gleason 3 glands only. In this work we propose a novel framework employing multiple techniques to generate integrated metrics of morphology and biomarker expression. We demonstrate the utility of the approaches in predicting clinical disease progression in images from 326 prostate biopsies and 373 prostatectomies. Our proposed integrative approaches yield significant improvements over existing IF image feature metrics. This work presents some of the first algorithms for generating innovative characteristics in tissue diagnostics that integrate co-localized morphometry and protein biomarker expression.

  5. Salivary gland acinar cells regenerate functional glandular structures in modified hydrogels

    NASA Astrophysics Data System (ADS)

    Pradhan, Swati

    Xerostomia, a condition resulting from irradiation of the head and neck, affects over 40,000 cancer patients each year in the United States. Direct radiation damage of the acinar cells that secrete fluid and protein results in salivary gland hypofunction. Present medical management for xerostomia for patients treated for upper respiratory cancer is largely ineffective. Patients who have survived their terminal diagnosis are often left with a diminished quality of life and are unable to enjoy the simple pleasures of eating and drinking. This project aims to ultimately reduce human suffering by developing a functional implantable artificial salivary gland. The goal was to create an extracellular matrix (ECM) modified hyaluronic acid (HA) based hydrogel culture system that allows for the growth and differentiation of salivary acinar cells into functional acini-like structures capable of secreting large amounts of protein and fluid unidirectionally and to ultimately engineer a functional artificial salivary gland that can be implanted into an animal model. A tissue collection protocol was established and salivary gland tissue was obtained from patients undergoing head and neck surgery. The tissue specimen was assessed by histology and immunohistochemistry to establish the phenotype of normal salivary gland cells including the native basement membranes. Hematoxylin and eosin staining confirmed normal glandular tissue structures including intercalated ducts, striated ducts and acini. alpha-Amylase and periodic acid schiff stain, used for structures with a high proportion of carbohydrate macromolecules, preferentially stained acinar cells in the tissue. Intercalated and striated duct structures were identified using cytokeratins 19 and 7 staining. Myoepithelial cells positive for cytokeratin 14 were found wrapped around the serous and mucous acini. Tight junction components including ZO-1 and E-cadherin were present between both ductal and acinar cells. Ductal and acinar

  6. High-Speed On-Board Data Processing for Science Instruments: HOPS

    NASA Technical Reports Server (NTRS)

    Beyon, Jeffrey

    2015-01-01

    The project called High-Speed On-Board Data Processing for Science Instruments (HOPS) has been funded by NASA Earth Science Technology Office (ESTO) Advanced Information Systems Technology (AIST) program during April, 2012 â€" April, 2015. HOPS is an enabler for science missions with extremely high data processing rates. In this three-year effort of HOPS, Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) and 3-D Winds were of interest in particular. As for ASCENDS, HOPS replaces time domain data processing with frequency domain processing while making the real-time on-board data processing possible. As for 3-D Winds, HOPS offers real-time high-resolution wind profiling with 4,096-point fast Fourier transform (FFT). HOPS is adaptable with quick turn-around time. Since HOPS offers reusable user-friendly computational elements, its FPGA IP Core can be modified for a shorter development period if the algorithm changes. The FPGA and memory bandwidth of HOPS is 20 GB/sec while the typical maximum processor-to-SDRAM bandwidth of the commercial radiation tolerant high-end processors is about 130-150 MB/sec. The inter-board communication bandwidth of HOPS is 4 GB/sec while the effective processor-to-cPCI bandwidth of commercial radiation tolerant high-end boards is about 50-75 MB/sec. Also, HOPS offers VHDL cores for the easy and efficient implementation of ASCENDS and 3-D Winds, and other similar algorithms. A general overview of the 3-year development of HOPS is the goal of this presentation.

  7. Intermediate tunnelling-hopping regime in DNA charge transport

    NASA Astrophysics Data System (ADS)

    Xiang, Limin; Palma, Julio L.; Bruot, Christopher; Mujica, Vladimiro; Ratner, Mark A.; Tao, Nongjian

    2015-03-01

    Charge transport in molecular systems, including DNA, is involved in many basic chemical and biological processes, and its understanding is critical if they are to be used in electronic devices. This important phenomenon is often described as either coherent tunnelling over a short distance or incoherent hopping over a long distance. Here, we show evidence of an intermediate regime where coherent and incoherent processes coexist in double-stranded DNA. We measure charge transport in single DNA molecules bridged to two electrodes as a function of DNA sequence and length. In general, the resistance of DNA increases linearly with length, as expected for incoherent hopping. However, for DNA sequences with stacked guanine-cytosine (GC) base pairs, a periodic oscillation is superimposed on the linear length dependence, indicating partial coherent transport. This result is supported by the finding of strong delocalization of the highest occupied molecular orbitals of GC by theoretical simulation and by modelling based on the Büttiker theory of partial coherent charge transport.

  8. Intermediate tunnelling-hopping regime in DNA charge transport.

    PubMed

    Xiang, Limin; Palma, Julio L; Bruot, Christopher; Mujica, Vladimiro; Ratner, Mark A; Tao, Nongjian

    2015-03-01

    Charge transport in molecular systems, including DNA, is involved in many basic chemical and biological processes, and its understanding is critical if they are to be used in electronic devices. This important phenomenon is often described as either coherent tunnelling over a short distance or incoherent hopping over a long distance. Here, we show evidence of an intermediate regime where coherent and incoherent processes coexist in double-stranded DNA. We measure charge transport in single DNA molecules bridged to two electrodes as a function of DNA sequence and length. In general, the resistance of DNA increases linearly with length, as expected for incoherent hopping. However, for DNA sequences with stacked guanine-cytosine (GC) base pairs, a periodic oscillation is superimposed on the linear length dependence, indicating partial coherent transport. This result is supported by the finding of strong delocalization of the highest occupied molecular orbitals of GC by theoretical simulation and by modelling based on the Büttiker theory of partial coherent charge transport. PMID:25698331

  9. Hops for Menopausal Vasomotor Symptoms: Mechanisms of Action.

    PubMed

    Abdi, Fatemeh; Mobedi, Hamid; Roozbeh, Nasibeh

    2016-08-01

    Menopause is a critical stage of women's life associated with various complaints and distresses. Vasomotor symptoms (VMS), such as hot flushes, night sweats, sleep disturbances, and fatigue, are the most common menopause symptoms affecting about 50% to 80% of middle-aged women. Obviously, these symptoms, resulting from estrogen deficiency during menopause, can exert negative effects on women's health and quality of life and thus require to be managed through approaches such as hormone replacement therapy (HRT). Many herbal treatments for menopause symptoms contain and its components such as 8-prenylnaringenin, 6-PN, isoxanthohumol and xanthohumol. Recent in-vivo studies have highlighted the ability of 8-prenylnaringenin to reduce serum-luteinizing hormone (LH) and follicle-stimulating hormone (FSH), to increase serum prolactin levels and uterine weight, and to induce vaginal hyperplastic epithelium. Previous research has shown that hops extract can strongly bind to both estrogen receptors, stimulate alkaline phosphatase activity in Ishikawa cells, and upregulate presenelin-2 and progesterone receptor mRNA in Ishikawa cells. Numerous clinical trials have documented significant reductions in the frequency of hot flushes following the administration of hop-containing preparations. Nevertheless, further clinical trials with larger sample size and longer follow-up are warranted to confirm such benefits. PMID:27617238

  10. Frequency hopping millimeter-wave reflectometry in ASDEX upgrade

    SciTech Connect

    Cupido, L.; Graca, S.; Conway, G. D.; Manso, M.; Serra, F.

    2006-10-15

    Millimeter-wave reflectometers for performing density fluctuations have traditionally used either tunable fixed frequency (heterodyne and homodyne) systems or multichannel fixed frequency arrangements. Only recently novel systems were brought into operation with the ability to hop from one frequency to another over a large bandwidth, during each plasma discharge, while retaining the quality of fixed frequency phase locked sources. The new broadband fast hopping millimeter-wave reflectometer incorporates frequency synthesizers for both plasma signal and local oscillators, and the receivers are heterodyne producing full phase/amplitude outputs. Two identical systems were recently installed in (ASDEX upgrade tokamak - IPP-MPG Germany) covering the Q band (33-50 GHz) and the V band (50-75 GHz). In the present article the system is described and the particular implementation on ASDEX, using monostatic antenna system, is presented showing the possibility of correlation studies in fully optimized antenna scenarios. With both Q and V channels in operation it was possible to devise several operation schemes that are described here and a result showing the radial localization of magnetohydrodynamic activity is also presented.

  11. Communication: Global flux surface hopping in Liouville space.

    PubMed

    Wang, Linjun; Sifain, Andrew E; Prezhdo, Oleg V

    2015-11-21

    Recent years have witnessed substantial progress in the surface hopping (SH) formulation of non-adiabatic molecular dynamics. A generalization of the traditional fewest switches SH (FSSH), global flux SH (GFSH) utilizes the gross population flow between states to derive SH probabilities. The Liouville space formulation of FSSH puts state populations and coherences on equal footing, by shifting the hopping dynamics from Hilbert to Liouville space. Both ideas have shown superior results relative to the standard FSSH in Hilbert space, which has been the most popular approach over the past two and a half decades. By merging the two ideas, we develop GFSH in Liouville space. The new method is nearly as straightforward as the standard FSSH, and carries comparable computational expense. Tested with a representative super-exchange model, it gives the best performance among all existing techniques in the FSSH series. The obtained numerical results match almost perfectly the exact quantum mechanical solutions. Moreover, the results are nearly invariant under the choice of a basis state representation for SH, in contrast to the earlier techniques which exhibit notable basis set dependence. Unique to the developed approach, this property is particularly encouraging, because exact quantum dynamics is representation independent. GFSH in Liouville space significantly improves accuracy and applicability of SH for a broad range of chemical and physical processes. PMID:26590519

  12. Coding for frequency hopped spread spectrum satellite communications

    NASA Astrophysics Data System (ADS)

    Wang, Q.; Li, G.; Blake, I. F.; Bhargava, V. K.; Chen, Q.

    1992-04-01

    The performance of fast frequency hopped spread spectrum systems with M-ary frequency shift keying and error correction coding under jamming conditions are analyzed. Ratio threshold diversity combining is used. The decoding scheme is error erasure decoding with metrics generated by the diversity combiner. The bit error probability of the system is computed and improvements offered by error correction coding are shown. The performance of several error correction codes is compared under different channel conditions. The notion of an arbitrarily varying channel (AVC) is discussed, including capacities of AVC's and a discrete memoryless channel, and two Gaussian AVC models are described. Coded performance of a slow frequency hopped differential phase shift keying (DPSK) system in presence of both additive white Gaussian noise and tone jamming is studied. The error correlation due to DPSK demodulation and the effect of tone jamming are considered in evaluating the block and decoded error probabilities. The effect of interleaving on system performance is addressed. A nearly optimum code rate for a length 255 Reed-Solomon code is derived for systems employing interleaving. Finally, a parallel approach to the design of universal receivers for unknown and time-varying channels is applied to DPSK systems in the presence of noise and tone interference.

  13. Sequential vortex hopping in an array of artificial pinning centers

    SciTech Connect

    Keay, J. C.

    2010-02-24

    We use low-temperature magnetic force microscopy (MFM) to study the hopping motion of vortices in an array of artificial pinning centers (APCs). The array consists of nanoscale holes etched in a niobium thin film by Ar-ion sputtering through an anodic aluminum-oxide template. Variable-temperature magnetometry shows a transition temperature of 7.1 K and an enhancement of the magnetization up to the third matching field at 5 K. Using MFM with attractive and repulsive tip-vortex interaction, we measure the vortex-pinning strength and investigate the motion of individual vortices in the APC array. The depinning force for individual vortices at low field ranged from 0.7 to 1.2 pN. The motion of individual vortices was found to be reproducible and consistent with movement between adjacent holes in the film. The movements are repeatable but the sequence of hops depends on the scan direction. This asymmetry in the motion indicates nonuniform local pinning, a consequence of array disorder and hole-size variation.

  14. HOPS 383: AN OUTBURSTING CLASS 0 PROTOSTAR IN ORION

    SciTech Connect

    Safron, Emily J.; Megeath, S. Thomas; Booker, Joseph; Fischer, William J.; Furlan, Elise; Rebull, Luisa M.; Stutz, Amelia M.; Stanke, Thomas; Billot, Nicolas; Tobin, John J.; Ali, Babar; Allen, Lori E.; Watson, Dan M.; Wilson, T. L.

    2015-02-10

    We report the dramatic mid-infrared brightening between 2004 and 2006 of Herschel Orion Protostar Survey (HOPS) 383, a deeply embedded protostar adjacent to NGC 1977 in Orion. By 2008, the source became a factor of 35 brighter at 24 μm with a brightness increase also apparent at 4.5 μm. The outburst is also detected in the submillimeter by comparing APEX/SABOCA to SCUBA data, and a scattered-light nebula appeared in NEWFIRM K{sub s} imaging. The post-outburst spectral energy distribution indicates a Class 0 source with a dense envelope and a luminosity between 6 and 14 L{sub ⊙}. Post-outburst time-series mid- and far-infrared photometry show no long-term fading and variability at the 18% level between 2009 and 2012. HOPS 383 is the first outbursting Class 0 object discovered, pointing to the importance of episodic accretion at early stages in the star formation process. Its dramatic rise and lack of fading over a 6 year period hint that it may be similar to FU Ori outbursts, although the luminosity appears to be significantly smaller than the canonical luminosities of such objects.

  15. Communication: Global flux surface hopping in Liouville space

    NASA Astrophysics Data System (ADS)

    Wang, Linjun; Sifain, Andrew E.; Prezhdo, Oleg V.

    2015-11-01

    Recent years have witnessed substantial progress in the surface hopping (SH) formulation of non-adiabatic molecular dynamics. A generalization of the traditional fewest switches SH (FSSH), global flux SH (GFSH) utilizes the gross population flow between states to derive SH probabilities. The Liouville space formulation of FSSH puts state populations and coherences on equal footing, by shifting the hopping dynamics from Hilbert to Liouville space. Both ideas have shown superior results relative to the standard FSSH in Hilbert space, which has been the most popular approach over the past two and a half decades. By merging the two ideas, we develop GFSH in Liouville space. The new method is nearly as straightforward as the standard FSSH, and carries comparable computational expense. Tested with a representative super-exchange model, it gives the best performance among all existing techniques in the FSSH series. The obtained numerical results match almost perfectly the exact quantum mechanical solutions. Moreover, the results are nearly invariant under the choice of a basis state representation for SH, in contrast to the earlier techniques which exhibit notable basis set dependence. Unique to the developed approach, this property is particularly encouraging, because exact quantum dynamics is representation independent. GFSH in Liouville space significantly improves accuracy and applicability of SH for a broad range of chemical and physical processes.

  16. Hops for Menopausal Vasomotor Symptoms: Mechanisms of Action

    PubMed Central

    Abdi, Fatemeh; Mobedi, Hamid

    2016-01-01

    Menopause is a critical stage of women's life associated with various complaints and distresses. Vasomotor symptoms (VMS), such as hot flushes, night sweats, sleep disturbances, and fatigue, are the most common menopause symptoms affecting about 50% to 80% of middle-aged women. Obviously, these symptoms, resulting from estrogen deficiency during menopause, can exert negative effects on women's health and quality of life and thus require to be managed through approaches such as hormone replacement therapy (HRT). Many herbal treatments for menopause symptoms contain and its components such as 8-prenylnaringenin, 6-PN, isoxanthohumol and xanthohumol. Recent in-vivo studies have highlighted the ability of 8-prenylnaringenin to reduce serum-luteinizing hormone (LH) and follicle-stimulating hormone (FSH), to increase serum prolactin levels and uterine weight, and to induce vaginal hyperplastic epithelium. Previous research has shown that hops extract can strongly bind to both estrogen receptors, stimulate alkaline phosphatase activity in Ishikawa cells, and upregulate presenelin-2 and progesterone receptor mRNA in Ishikawa cells. Numerous clinical trials have documented significant reductions in the frequency of hot flushes following the administration of hop-containing preparations. Nevertheless, further clinical trials with larger sample size and longer follow-up are warranted to confirm such benefits. PMID:27617238

  17. Communication: Global flux surface hopping in Liouville space

    SciTech Connect

    Wang, Linjun E-mail: prezhdo@usc.edu; Prezhdo, Oleg V. E-mail: prezhdo@usc.edu; Sifain, Andrew E.

    2015-11-21

    Recent years have witnessed substantial progress in the surface hopping (SH) formulation of non-adiabatic molecular dynamics. A generalization of the traditional fewest switches SH (FSSH), global flux SH (GFSH) utilizes the gross population flow between states to derive SH probabilities. The Liouville space formulation of FSSH puts state populations and coherences on equal footing, by shifting the hopping dynamics from Hilbert to Liouville space. Both ideas have shown superior results relative to the standard FSSH in Hilbert space, which has been the most popular approach over the past two and a half decades. By merging the two ideas, we develop GFSH in Liouville space. The new method is nearly as straightforward as the standard FSSH, and carries comparable computational expense. Tested with a representative super-exchange model, it gives the best performance among all existing techniques in the FSSH series. The obtained numerical results match almost perfectly the exact quantum mechanical solutions. Moreover, the results are nearly invariant under the choice of a basis state representation for SH, in contrast to the earlier techniques which exhibit notable basis set dependence. Unique to the developed approach, this property is particularly encouraging, because exact quantum dynamics is representation independent. GFSH in Liouville space significantly improves accuracy and applicability of SH for a broad range of chemical and physical processes.

  18. Three-dimensional numerical simulations for activated hopping conduction

    NASA Astrophysics Data System (ADS)

    Zimmerman, Dan S.; Shegelski, Mark R. A.

    1988-07-01

    We model hopping conduction in a three-dimensional, lightly doped compensated semiconductor using a Miller-Abrahams-type resistor network. A flat density of states of width Δɛ is used. We work with the full expression for the resistances instead of the T-->0 asymptotic form usually employed. We report the first detailed numerical calculations of the overall resistance of a three-dimensional resistor network using this full expression. We find a temperature regime where the hopping conduction has a ratio of activation energy to bandwidth ɛ~3=ɛ3/Δɛ=0.217(8). This value agrees with the analytically determined value calculated by Shegelski and Barrie (SB), and disagrees with results reported by other workers, thereby validating SB's analytic theory and their claim that the full expression for the resistor network should be used in calculations of ɛ~3. An investigation is made into the dependence of ɛ~3 on Δɛ we find, in qualitative agreement with SB, that ɛ~3 decreases with Δɛ and we present improved values for ɛ~3 as a function of Δɛ.

  19. Post-Civil Rights Music; or Why Hip Hop Is Dominant

    ERIC Educational Resources Information Center

    Walcott, Rinaldo

    2005-01-01

    Hip hop is the most multicultural of popular musical forms--all races and ethnicities are involved. Simultaneously hip hop is also the most racialized, and indeed the most blackened, musical form of individuals' times. How did this happen and why should it be of interests to music scholars? In this short essay, the author attempts to suggest that…

  20. Characterization of the Mammalian CORVET and HOPS Complexes and Their Modular Restructuring for Endosome Specificity.

    PubMed

    van der Kant, Rik; Jonker, Caspar T H; Wijdeven, Ruud H; Bakker, Jeroen; Janssen, Lennert; Klumperman, Judith; Neefjes, Jacques

    2015-12-18

    Trafficking of cargo through the endosomal system depends on endosomal fusion events mediated by SNARE proteins, Rab-GTPases, and multisubunit tethering complexes. The CORVET and HOPS tethering complexes, respectively, regulate early and late endosomal tethering and have been characterized in detail in yeast where their sequential membrane targeting and assembly is well understood. Mammalian CORVET and HOPS subunits significantly differ from their yeast homologues, and novel proteins with high homology to CORVET/HOPS subunits have evolved. However, an analysis of the molecular interactions between these subunits in mammals is lacking. Here, we provide a detailed analysis of interactions within the mammalian CORVET and HOPS as well as an additional endosomal-targeting complex (VIPAS39-VPS33B) that does not exist in yeast. We show that core interactions within CORVET and HOPS are largely conserved but that the membrane-targeting module in HOPS has significantly changed to accommodate binding to mammalian-specific RAB7 interacting lysosomal protein (RILP). Arthrogryposis-renal dysfunction-cholestasis (ARC) syndrome-associated mutations in VPS33B selectively disrupt recruitment to late endosomes by RILP or binding to its partner VIPAS39. Within the shared core of CORVET/HOPS, we find that VPS11 acts as a molecular switch that binds either CORVET-specific TGFBRAP1 or HOPS-specific VPS39/RILP thereby allowing selective targeting of these tethering complexes to early or late endosomes to time fusion events in the endo/lysosomal pathway. PMID:26463206

  1. Trends in German Hip Hop Music and Its Usefulness for the Classroom

    ERIC Educational Resources Information Center

    Schmidt, Johannes

    2008-01-01

    German hip hop music has proved productive, especially since 2000 when rap in Germany experienced something like a first crisis. As a response, German hip hop artists and record labels have ventured off in several different directions including other musical genres, different topics, and new approaches to German rap. This article discusses the…

  2. New outbreaks of verticillium wilt on Hop in Oregon caused by nonlethal verticillium albo-atrum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2006 and 2007, new outbreaks of Verticillium wilt on hop were detected on two farms in Oregon. Verticillium pathogens vary in their virulence to hop; some strains cause minor damage but others can kill susceptible cultivars. Studies were conducted to determine the identity of the Verticillium sp...

  3. Supporting Communication and Argumentation in Urban Science Education: Hip-Hop, the Battle, and the Cypher

    ERIC Educational Resources Information Center

    Emdin, Christopher

    2011-01-01

    This paper is based on an exploration of communication and argumentation in urban science classrooms, and provides a description of the role that Hip-hop based education plays in supporting these major components of science education. The paper is intended to both support, and critique conventional uses of hip-hop based education, and provide…

  4. Hegemony, Hope, and the Harlem Renaissance: Taking Hip Hop Culture Seriously

    ERIC Educational Resources Information Center

    Price, Robert J., Jr.

    2005-01-01

    Adult education instructors and administrators, who typically are not members of the hip hop generation, often have little knowledge and understanding of rap music (also known as gangsta rap) and hip hop culture, and consequently do not take the black popular cultural phenomenon seriously as it relates to adult education. Adult educators,…

  5. Proust, Hip-Hop, and Death in First-Year Composition

    ERIC Educational Resources Information Center

    Sirc, Geoffrey

    2006-01-01

    Hip-hop as content in a first-year writing course offers students a powerful way to connect with their worlds. This article draws on Marcel Proust as a kind of rhyme to legitimate hip-hop as a substantive expressive medium to achieve artistry in writing.

  6. Sampling Practices and Social Spaces: Exploring a Hip-Hop Approach to Higher Education

    ERIC Educational Resources Information Center

    Petchauer, Emery

    2010-01-01

    Much more than a musical genre, hip-hop culture exists as an animating force in the lives of many young adults. This article looks beyond the moral concerns often associated with rap music to explore how hip-hop as a larger set of expressions and practices implicates the educational experiences, activities, and approaches for students. The article…

  7. Representin': Drawing from Hip-Hop and Urban Youth Culture to Inform Teacher Education

    ERIC Educational Resources Information Center

    Irizarry, Jason G.

    2009-01-01

    The potential of drawing from urban youth culture, and hip-hop more specifically, to serve as a bridge to the standard curriculum has been well documented. However, the richness and potential benefits of hip-hop are more far-reaching and present significant implications for teacher education and professional development efforts as well. This…

  8. Student Perceptions of the Hip Hop Culture's Influence on the Undergraduate Experience

    ERIC Educational Resources Information Center

    Wessel, Roger D.; Wallaert, Kerry A.

    2011-01-01

    This study sought to determine how identification and engagement with the hip hop culture influenced the educational experiences of undergraduate students at a Midwestern, predominately White university by interviewing 11 students who self-identified as being immersed in the hip hop culture. Through a qualitative, phenomenological investigation,…

  9. Hip-Hop, Social Justice, and Environmental Education: Toward a Critical Ecological Literacy

    ERIC Educational Resources Information Center

    Cermak, Michael J.

    2012-01-01

    This essay describes an educational initiative that used environmentally themed (green) hip-hop to stimulate learning in an environmental science classroom. Students were then challenged to compose their own green hip-hop and their lyrics demonstrated skills that have thematic consistency around what is called a Critical Ecological Literacy (CEL).…

  10. Wounded Healing: Forming a Storytelling Community in Hip-Hop Lit

    ERIC Educational Resources Information Center

    Hill, Marc Lamont

    2009-01-01

    Background/Context: Over the past 5 years, there has been a growing body of scholarship that examines the intersections of hip-hop culture and classroom pedagogy. Although recent scholarship has persuasively demonstrated the classroom potential of hip-hop texts for promoting student engagement, scaffolding sanctioned forms of knowledge, and…

  11. Deal with It We Must: Education, Social Justice, and the Curriculum of Hip Hop Culture

    ERIC Educational Resources Information Center

    Baszile, Denise Taliaferro

    2009-01-01

    Although hip hop culture has been one of the most significant urban youth movements over the last three decades, it has only recently gained attention within the educational literature as a force to be reckoned with. And even then, much of the literature seeks to understand how hip hop can be used to engage students in the official school…

  12. Hip-Hop and a Hybrid Text in a Postsecondary English Class

    ERIC Educational Resources Information Center

    Sanchez, Deborah M.

    2010-01-01

    This study explores the epistemology present in hip-hop music and its reflection in the writing of one African American student in a postsecondary transitional English class. An integration of hip-hop and academic literacy practices in the student's essay challenges the supremacy of a "standard" academic English and deficit perspectives about…

  13. Hip-Hop Culture in College Students' Lives: Elements, Embodiment, and Higher Edutainment

    ERIC Educational Resources Information Center

    Petchauer, Emery

    2011-01-01

    College campuses have become rich sites of hip-hop culture and knowledge production. Despite the attention that campus personnel and researchers have paid to student life, the field of higher education has often misunderstood the ways that hip-hop culture exists in college students' lives. Based upon in-depth interviews, observations of…

  14. Teaching Controversal Topics in Contemporary German Culture through Hip-Hop

    ERIC Educational Resources Information Center

    Putnam, Michael

    2006-01-01

    This article discusses the rich cultural resources embedded with German hip-hop music and its potential impact on the foreign language classroom. In particular, this article suggests methods and materials for integrating German hip-hop music in the discussion of recent controversial cultural events and attitudes in German after the "Wende."

  15. Empowerment in Context: Lessons from Hip-Hop Culture for Social Work Practice

    ERIC Educational Resources Information Center

    Travis, Raphael, Jr.; Deepak, Anne

    2011-01-01

    Hip-hop culture can be used as a conduit to enhanced cultural competence and practice skills through the individual and community empowerment framework. This framework is introduced as a tool for direct practice that allows social workers to understand the competing messages within hip-hop culture and how they may impact youths by promoting or…

  16. We Can Relate: Hip-Hop Culture, Critical Pedagogy, and the Secondary Classroom

    ERIC Educational Resources Information Center

    Stovall, David

    2006-01-01

    This article seeks to locate hip-hop in the realm of popular culture in education. Through the use of song lyrics, the author suggests the use of rap music to provide context for the humanities and social sciences in secondary curriculum. Using a theoretical and practical lens, the article argues for the use of hip-hop and other elements of…

  17. Polish Hip Hop as a Form of Multiliteracies and Situated Learning

    ERIC Educational Resources Information Center

    Torrence, Michael L.

    2009-01-01

    The purpose of this ethnographic study was to examine Hip Hop in Poland through the lens of multiliteracies and situated learning. This analysis is concerned with the transmission of Hip Hop to and within Wroclaw, Poland, and its acculturation and assimilation in Wroclaw, Poland. Further, this study seeks to illustrate how professional Polish Hip…

  18. Hip-Hop's Influence on the Identity Development of Black Female College Students: A Literature Review

    ERIC Educational Resources Information Center

    Henry, Wilma J.; West, Nicole M.; Jackson, Andrea

    2010-01-01

    This article explores unique issues regarding the effects of hip-hop culture on the identity development of young Black female college students. Through the lenses of womanist and Black feminist perspectives, the intersecting impact of race and gender are reviewed within the context of the competing influences of hip-hop on Black female identity.…

  19. Affiliation and Alienation: Hip-Hop, Rap, and Urban Science Education

    ERIC Educational Resources Information Center

    Emdin, Christopher

    2010-01-01

    The critiques of rap artists and other participants in hip-hop culture provide data for teachers and researchers to investigate the attitudes of US urban youth towards schooling. This study explores the complex relationships between hip-hop and science education by examining how rap lyrics project beliefs about schooling, the relevance of existing…

  20. Helicobacter pylori hopQ alleles (type I and II) in gastric cancer

    PubMed Central

    LEYLABADLO, HAMED EBRAHIMZADEH; YEKANI, MINA; GHOTASLOU, REZA

    2016-01-01

    The Helicobacter pylori (H. pylori) outer membrane protein (HopQ) of is one of the proteins involved in bacterial adherence to gastric mucosa and has been suggested to have a role in the virulence of H. pylori. The aim of the present study was to determine the association between H. pylori virulence types I and II hopQ genotypes and patients with different gastrointestinal diseases. A polymerase chain reaction-based assay was used to determine the presence of type I and type II hopQ genes in 88 H. pylori strains isolated from H. pylori-infected patients. Of the total 88 H. pylori isolates, type I and type II hopQ alleles were detected in 52 (59.1%) and 36 (40.9%), respectively. A significant association was found between type I hopQ gene and gastric cancer [odds ratio, 2.3; 95% confidence interval (CI), 1.3–4.1] and gastric ulcers (odds ratio, 2.5; 95% CI, 1.4–4.3). A significant association was also identified between the type II hopQ gene and gastric cancer (odds ratio, 2.4; 95% CI, 1.1–3.0). The association between hopQ type I and hopQ type II genotypes and clinical status suggest that these genes may be helpful in the universal prediction of specific disease risks. PMID:27123254

  1. Language, Localization, and the Real: Hip-Hop and the Global Spread of Authenticity

    ERIC Educational Resources Information Center

    Pennycook, Alastair

    2007-01-01

    This article addresses the relationship between the call for authenticity, its relocalization in other contexts, and the use of English. Hip-hop forces us to confront some of the conflictual discourses of authenticity and locality, from those that insist that African American hip-hop is the only real variety and that all other forms are…

  2. Predicting Offspring Performance in Hop (Humulus lupulus L.) Using AFLP Markers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pedigree and combining ability information for male and female hop accessions is limited and choice of breeding parents remains guesswork. This studies’ objective was to determine if AFLP markers could be used to predict offspring performance in hop. AFLP assays were used to estimate genetic dista...

  3. Day Care Hopping: Stabilizing Day Care Options for Low-Income Mothers through Subsidies

    ERIC Educational Resources Information Center

    Drentea, Patricia; Durham, Suzanne; Mwaria, Mercie; Norman, Emily; Xi, Juan

    2004-01-01

    We examined how to allocate a subsidy to low-income women that would stabilize children in day care at a Young Women's Christian Association (YWCA). The subsidy is to alleviate day care hopping (i.e. when parents move from day care to day care) leaving unpaid tuitions at each place. Day care hopping is really a survival strategy for the working…

  4. Dynamic jamming effects on code synchronization of frequency-hop spread-spectrum

    NASA Astrophysics Data System (ADS)

    van Grouw, M. G.; Wickert, M. A.

    1989-06-01

    A general scheme for the code synchronization of Frequency-Hop Spread-Spectrum (FHSS) is presented. Synchronization performance is observed in the presence of channel dynamics and is characterized by mean synchronization time and mean time to loss of lock. A fixed-threshold multiple-dwell synchronization scheme is shown to adequately mitigate the effects of random hop jamming.

  5. Association between Helicobacter pylori hopQI genotypes and human gastric cancer risk.

    PubMed

    Kazemi, E; Kahrizi, D; Moradi, M T; Sohrabi, M; Amini, S; Mousavi, S A R; Yari, K

    2016-01-01

    The Helicobacter pylori use a number of mechanisms to survive in the stomach lumen and can lead to gastritis and reduction in stomach acid secretion. It has been found that the risk of developing gastric carcinoma is associated to heterogeneity of H. pylori virulence factors such as HopQ. The HopQ is one of the outer membrane proteins involved in bacterial adherence to gastric mucosa and has been suggested to also main role in the virulence of H. pylori. The purpose of the current study was to investigate the association between different H. pylori virulence hopQI (types I) genotyping and patients with gastroduodenal disorders. For this purpose 58 stomach biopsies of the patients with gastric cancer and 100 saliva samples from healthy and H. pylori infected individuals were collected and studied. Then genomic DNA was purified and PCR was done for desired gene via specific primers. The H. pylori infections were diagnosed using PCR for GlmM gene. Then frequencies of hopQI+ and hopQI- genotypes were determined in H. pylori infected cases. Statistical analysis showed that there were not significant differences between healthy and diseased ones for genotypes hopQI+ and hopQI-. Then the hopQI+ cannot be as a risk factor genotype for gastric cancer. PMID:26828979

  6. Electrically and optically detected spin echo of hopping carriers in organic semiconductors

    NASA Astrophysics Data System (ADS)

    Mkhitaryan, Vagharsh; Dobrovitski, Viatcheslav

    We develop a theory for electrically and optically detected primary (2-pulse) and stimulated (3-pulse) spin echo produced by the polaron pairs coupled to the nuclear spins in organic semiconductors. The theory employs fully quantum description of the nuclear and polaron spins, and explains how the structure of the echo signal (electron spin echo envelope modulation, ESEEM) depends on the statistics and rate of the polaron hopping. For the primary spin echo the envelope modulation is strong for slow hopping; both modulation amplitude and dephasing time T2 decrease with increasing hopping rate. As the hopping rate increases further, T2 starts to increase again due to motional narrowing, while the primary echo signal becomes exponential without modulation. The stimulated spin echo signal also shows strong envelope modulation for slow polaron hopping. For faster hopping the stimulated echo (unlike the primary echo) shows a modulation which does not disappear for fast hopping, and has the frequency of the nuclear Larmor precession. Besides describing the recent spin echo measurements in π-conjugated polymers, our work provides a way to directly determine the polaron hopping dynamics from the spin echo experiments. This work was supported by the Department of Energy-Basic Energy Sciences under Contract No. DE-AC02-07CH11358.

  7. Susceptibility of hop cultivars to downy mildew: associations with chemical characteristics and region of origin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hop downy mildew is a yield limiting disease in many hop production regions of the world. In this research, 110 cultivars that are or were widely grown in the U.S., Europe, or Australasia were evaluated in western Oregon over three years for their reaction to the shoot infection phase of downy mild...

  8. Effects of hops (Humulus lupulus L.) extract on volatile fatty acid production by rumen bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aims: To determine the effects of hops extract, on in vitro volatile fatty acid (VFA) production by bovine rumen microorganisms. Methods and Results: When mixed rumen microbes were suspended in media containing carbohydrates, the initial rates of VFA production were suppressed by beta-acid rich hops...

  9. Antimicrobial activity of hop extracts against Listeria monocytogenes in media and in food.

    PubMed

    Larson, A E; Yu, R R; Lee, O A; Price, S; Haas, G J; Johnson, E A

    1996-12-01

    Growth of Listeria monocytogenes was inhibited in culture media and in certain foods by four hop extracts (I-IV) containing varying concentrations of alpha-and beta-acids. Extracts (II and III) containing the highest concentrations of beta-acids were inhibitory at 0.01 mg/l in trypticase soy broth. In food, these hop extracts showed varying magnitudes of inhibition. In coleslaw, hop extract III at 1 mg/g enhanced the rate of inactivation of L. monocytogenes Scott A. Hop extract II was inhibitory at 0.1 and 1 mg/ml in skim and 2% milk, and was inhibitory at 1 mg/ml in whole milk. Hop extract II was listericidal in cottage cheese at 0.1 to 3 g/kg. No inhibition of L. monocytogenes by hop extract III was observed in Camembert cheese. Overall, the antimicrobial activity of hop extracts in food appeared to increase with acidity and lower fat content. Our results indicate that hop extracts could be used to control L. monocytogenes in minimally processed food with low fat content. PMID:8930705

  10. A Multicomponent UV Analysis of ["alpha"]- and ["beta"]-Acids in Hops

    ERIC Educational Resources Information Center

    Egts, Haley; Durben, Dan J.; Dixson, John A.; Zehfus, Micheal H.

    2012-01-01

    A method is presented for the determination of ["alpha"]- and ["beta"]-acids (humulones and lupulones) in a hops sample using a multicomponent UV spectroscopic analysis of a methanolic hop extract. When compared with standard methods, this lab can be considered "greener" because it uses smaller volumes of safer solvents (methanol instead of…

  11. The Antimicrobial Effects of Hops (Humulus lupulus L.) on Ruminal Hyper Ammonia-Producing Bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methods and Results: Media were prepared with dried hops or hops extract (30.7% lupulone), and inhibited ammonia production by mixed rumen bacteria. The growth and ammonia production of pure cultures (Peptostreptococcus anaerobius, Clostridium aminophilum, or Clostridium sticklandii) was inhibited ...

  12. Auxin regulates first leaf development and promotes the formation of protocorm trichomes and rhizome-like structures in developing seedlings of Spathoglottis plicata (Orchidaceae)

    PubMed Central

    Novak, Stacey D.; Whitehouse, Grace A.

    2013-01-01

    Auxin flows in a polar manner to target tissues and exert its morphogenic effect. Preventing auxin movement, with polar auxin transport (PAT) inhibitors, or increasing auxin levels in tissues through exogenous application can provide a means for assessing the importance of appropriate tissue distribution and concentration of this hormone during development. The formulation of culture media for micropropagation has been the primary focus of most orchid tissue culture research, a goal that unveils seedling hormone responses at a single point in development. This study was unique because it evaluated the auxin response of orchids during three stages of seedling development. Seedlings were grown on standard culture media for 10, 35 and 85 days. Each group was sub-cultured onto auxin- and/or PAT inhibitor-containing media for an additional 10, 30 and 60 days, respectively. Data were collected on first leaf initiation, trichome formation and the appearance of propagative structures. In the 20-day seedlings, auxins and PAT inhibitors promoted precocious formation and random placement of protocorm hairs rather than in tufts, as seen in older, control seedlings. The 65-day seedlings formed protocorm-like bodies, rhizome-like growths from the stem, and fleshy leaves with trichomes. Seedlings cultured for 145 days developed microshoots or callus growth in the axils of older leaves and exhibited necrosis of original seedling roots and leaves. In general, exogenously applied auxin promoted the reversion of differentiated Spathoglottis plicata seedling tissue to a morphology that had propagative properties. Additionally, auxins commonly induced hair formation, which suggests that protocorm hairs may be root hair-like in nature. This work characterized three auxin growth responses in S. plicata seedlings that have not been reported in orchids: (i) the inhibition of first leaf initiation and abnormal first leaf morphology; (ii) the promotion of trichome formation; and (iii) the

  13. The Immunophilin-Interacting Protein AtFIP37 from Arabidopsis Is Essential for Plant Development and Is Involved in Trichome Endoreduplication1

    PubMed Central

    Vespa, Laurent; Vachon, Gilles; Berger, Frédéric; Perazza, Daniel; Faure, Jean-Denis; Herzog, Michel

    2004-01-01

    The FKBP12 (FK506-binding protein 12 kD) immunophilin interacts with several protein partners in mammals and is a physiological regulator of the cell cycle. In Arabidopsis, only one specific partner of AtFKBP12, namely AtFIP37 (FKBP12 interacting protein 37 kD), has been identified but its function in plant development is not known. We present here the functional analysis of AtFIP37 in Arabidopsis. Knockout mutants of AtFIP37 show an embryo-lethal phenotype that is caused by a strong delay in endosperm development and embryo arrest. AtFIP37 promoter::β-glucuronidase reporter gene constructs show that the gene is expressed during embryogenesis and throughout plant development, in undifferentiating cells such as meristem or embryonic cells as well as highly differentiating cells such as trichomes. A translational fusion with the enhanced yellow fluorescent protein indicates that AtFIP37 is a nuclear protein localized in multiple subnuclear foci that show a speckled distribution pattern. Overexpression of AtFIP37 in transgenic lines induces the formation of large trichome cells with up to six branches. These large trichomes have a DNA content up to 256C, implying that these cells have undergone extra rounds of endoreduplication. Altogether, these data show that AtFIP37 is critical for life in Arabidopsis and implies a role for AtFIP37 in the regulation of the cell cycle as shown for FKBP12 and TOR (target of rapamycin) in mammals. PMID:15047892

  14. Expression of Brassica napus TTG2, a regulator of trichome development, increases plant sensitivity to salt stress by suppressing the expression of auxin biosynthesis genes.

    PubMed

    Li, Qingyuan; Yin, Mei; Li, Yongpeng; Fan, Chuchuan; Yang, Qingyong; Wu, Jian; Zhang, Chunyu; Wang, Hong; Zhou, Yongming

    2015-09-01

    WRKY transcription factors (TFs) are plant specific and play important roles in regulating diverse biological processes. To identify TFs with broad-spectrum effects on various stress responses in Brassica napus, an important oil crop grown across diverse ecological regions worldwide, we functionally characterized Bna.TTG2 genes, which are homologous to the Arabidopsis AtTTG2 (WRKY44) gene. Four Bna.TTG2 genes were capable of rescuing the trichome phenotypes of Arabidopsis ttg2 mutants. Overexpressing one Bna.TTG2 family member, BnaA.TTG2.a.1, remarkably increased trichome numbers in Arabidopsis and B. napus plants. Interestingly, the BnaA.TTG2.a.1-overexpressing plants of both species exhibited increased sensitivity to salt stress. In BnaA.TTG2.a.1-overexpressing Arabidopsis under salt stress, the endogenous indole-3-acetic acid (IAA) content was reduced, and the expression of two auxin biosynthesis genes, TRYPTOPHAN BIOSYNTHESIS 5 (TRP5) and YUCCA2 (YUC2), was downregulated. The results from yeast one-hybrid, electrophoretic mobility shift, and dual-luciferase reporter assays revealed that BnaA.TTG2.a.1 is able to bind to the promoters of TRP5 and YUC2. These data indicated that BnaA.TTG2.a.1 confers salt sensitivity to overexpressing plants by suppressing the expression of IAA synthesis genes and thus lowering IAA levels. Transgenic Arabidopsis plants with an N-terminus-deleted BnaA.TTG2.a.1 no longer showed hypersensitivity to salt stress, suggesting that the N terminus of BnaA.TTG2.a.1 plays a critical role in salt stress responses. Therefore, in addition to its classical function in trichome development, our study reveals a novel role for Bna.TTG2 genes in salt stress responses. PMID:26071533

  15. Protein structure prediction: assembly of secondary structure elements by basin-hopping.

    PubMed

    Hoffmann, Falk; Vancea, Ioan; Kamat, Sanjay G; Strodel, Birgit

    2014-10-20

    The prediction of protein tertiary structure from primary structure remains a challenging task. One possible approach to this problem is the application of basin-hopping global optimization combined with an all-atom force field. In this work, the efficiency of basin-hopping is improved by introducing an approach that derives tertiary structures from the secondary structure assignments of individual residues. This approach is termed secondary-to-tertiary basin-hopping and benchmarked for three miniproteins: trpzip, trp-cage and ER-10. For each of the three miniproteins, the secondary-to-tertiary basin-hopping approach successfully and reliably predicts their three-dimensional structure. When it is applied to larger proteins, correctly folded structures are obtained. It can be concluded that the assembly of secondary structure elements using basin-hopping is a promising tool for de novo protein structure prediction. PMID:25056272

  16. Restoring phase coherence in a one-dimensional superconductor using power-law electron hopping

    NASA Astrophysics Data System (ADS)

    Lobos, Alejandro M.; Tezuka, Masaki; García-García, Antonio M.

    2013-10-01

    In a one-dimensional (1D) superconductor, zero-temperature quantum fluctuations destroy phase coherence. Here we put forward a mechanism which can restore phase coherence: power-law hopping. We study a 1D attractive-U Hubbard model with power-law hopping using Abelian bosonization and density-matrix renormalization group (DMRG) techniques. The parameter that controls the hopping decay acts as the effective, noninteger spatial dimensionality deff. For real-valued hopping amplitudes we identify analytically a range of parameters for which power-law hopping suppresses fluctuations and restores superconducting long-range order for any deff>1, at zero temperature. A detailed DMRG analysis fully supports these findings. These results are also of direct relevance to quantum magnetism as our model can be mapped onto an S=1/2 XXZ spin chain with power-law decaying couplings, which can be studied experimentally with cold-ion-trap techniques.

  17. Leg stiffness of older and younger individuals over a range of hopping frequencies.

    PubMed

    Hobara, Hiroaki; Kobayashi, Yoshiyuki; Yoshida, Eiichi; Mochimaru, Masaaki

    2015-04-01

    The purpose of this study was to compare spring-mass behavior between older and younger individuals at a range of hopping frequencies. A total of 14 elderly and 14 young subjects performed in-place hopping in time with a metronome at frequencies of 2.2, 2.6, and 3.0 Hz. Using a spring-mass model, leg stiffness was calculated as the ratio of maximum ground reaction force to maximum center of mass displacement at the middle of the stance phase during ground contact. The lower extremities of both groups behaved like a simple spring-mass system at all three hopping frequencies. Further, statistical analysis revealed the existence of a significant interaction between hopping frequency and age group on leg stiffness. These results suggest that the sensitivity of leg stiffness to accommodate for variations in hopping frequency is likely to differ between elderly and young individuals. PMID:25716326

  18. Lateral Hopping of CO on Ag(110) by Multiple Overtone Excitation.

    PubMed

    Oh, Junepyo; Lim, Hyunseob; Arafune, Ryuichi; Jung, Jaehoon; Kawai, Maki; Kim, Yousoo

    2016-02-01

    A novel type of action spectrum representing multiple overtone excitations of the v(M-C) mode was observed for lateral hopping of a CO molecule on Ag(110) induced by inelastically tunneled electrons from the tip of a scanning tunneling microscope. The yield of CO hopping shows sharp increases at 261±4  mV, corresponding to the C-O internal stretching mode, and at 61±2, 90±2, and 148±7  mV, even in the absence of corresponding fundamental vibrational modes. The mechanism of lateral CO hopping on Ag(110) was explained by the multistep excitation of overtone modes of v(M-C) based on the numerical fitting of the action spectra, the nonlinear dependence of the hopping rate on the tunneling current, and the hopping barrier obtained from thermal diffusion experiments. PMID:26894720

  19. Structural basis of Vps33A recruitment to the human HOPS complex by Vps16

    PubMed Central

    Graham, Stephen C.; Wartosch, Lena; Gray, Sally R.; Scourfield, Edward J.; Deane, Janet E.; Luzio, J. Paul; Owen, David J.

    2013-01-01

    The multisubunit homotypic fusion and vacuole protein sorting (HOPS) membrane-tethering complex is required for late endosome-lysosome and autophagosome-lysosome fusion in mammals. We have determined the crystal structure of the human HOPS subunit Vps33A, confirming its identity as a Sec1/Munc18 family member. We show that HOPS subunit Vps16 recruits Vps33A to the human HOPS complex and that residues 642–736 are necessary and sufficient for this interaction, and we present the crystal structure of Vps33A in complex with Vps16(642–736). Mutations at the binding interface disrupt the Vps33A–Vps16 interaction both in vitro and in cells, preventing recruitment of Vps33A to the HOPS complex. The Vps33A–Vps16 complex provides a structural framework for studying the association between Sec1/Munc18 proteins and tethering complexes. PMID:23901104

  20. Lateral Hopping of CO on Ag(110) by Multiple Overtone Excitation

    NASA Astrophysics Data System (ADS)

    Oh, Junepyo; Lim, Hyunseob; Arafune, Ryuichi; Jung, Jaehoon; Kawai, Maki; Kim, Yousoo

    2016-02-01

    A novel type of action spectrum representing multiple overtone excitations of the v (M -C ) mode was observed for lateral hopping of a CO molecule on Ag(110) induced by inelastically tunneled electrons from the tip of a scanning tunneling microscope. The yield of CO hopping shows sharp increases at 261 ±4 mV , corresponding to the C-O internal stretching mode, and at 61 ±2 , 90 ±2 , and 148 ±7 mV , even in the absence of corresponding fundamental vibrational modes. The mechanism of lateral CO hopping on Ag(110) was explained by the multistep excitation of overtone modes of v (M -C ) based on the numerical fitting of the action spectra, the nonlinear dependence of the hopping rate on the tunneling current, and the hopping barrier obtained from thermal diffusion experiments.

  1. Structural elucidation of humulone autoxidation products and analysis of their occurrence in stored hops.

    PubMed

    Taniguchi, Yoshimasa; Taniguchi, Harumi; Matsukura, Yasuko; Kawachi, Yasuji; Shindo, Kazutoshi

    2014-06-27

    The transformation of α-acids [in hops (Humulus lupulus L.)] to iso-α-acids (in beer) during the brewing process is well known, but the occurrence and structure of the oxidized α-acids during hop storage are not well documented. Because an understanding of these oxidized compounds is essential to optimize the effects of oxidized hops on the quality of beer, we investigated the autoxidation products of humulone (a representative congener of α-acids) using a simplified autoxidation model. Among the oxidation products, tricyclooxyisohumulones A (1) and B (2), tricycloperoxyisohumulone A (3), deisopropyltricycloisohumulone (4), and the hemiacetal 5 of tricycloperoxyhumulone A (5') were isolated, and their structures were elucidated for the first time. The occurrence of compounds 1-4 in stored hops was verified using LC/MS/MS analysis. We also monitored the levels of compounds 1-4 during hop storage using LC/MS/MS analysis. PMID:24875004

  2. Mean glandular dose coefficients (D(g)N) for x-ray spectra used in contemporary breast imaging systems.

    PubMed

    Nosratieh, Anita; Hernandez, Andrew; Shen, Sam Z; Yaffe, Martin J; Seibert, J Anthony; Boone, John M

    2015-09-21

    To develop tables of normalized glandular dose coefficients D(g)N for a range of anode-filter combinations and tube voltages used in contemporary breast imaging systems. Previously published mono-energetic D(g)N values were used with various spectra to mathematically compute D(g)N coefficients. The tungsten anode spectra from TASMICS were used; molybdenum and rhodium anode-spectra were generated using MCNPX Monte Carlo code. The spectra were filtered with various thicknesses of Al, Rh, Mo or Cu. An initial half value layer (HVL) calculation was made using the anode and filter material. A range of the HVL values was produced with the addition of small thicknesses of polymethyl methacrylate (PMMA) as a surrogate for the breast compression paddle, to produce a range of HVL values at each tube voltage. Using a spectral weighting method, D(g)N coefficients for the generated spectra were calculated for breast glandular densities of 0%, 12.5%, 25%, 37.5%, 50% and 100% for a range of compressed breast thicknesses from 3 to 8 cm. Eleven tables of normalized glandular dose (D(g)N) coefficients were produced for the following anode/filter combinations: W + 50 μm Ag, W + 500 μm Al, W + 700 μm Al, W + 200 μm Cu, W + 300 μm Cu, W + 50 μm Rh, Mo + 400 μm Cu, Mo + 30 μm Mo, Mo + 25 μm Rh, Rh + 400 μm Cu and Rh + 25 μm Rh. Where possible, these results were compared to previously published D(g)N values and were found to be on average less than 2% different than previously reported values.Over 200 pages of D(g)N coefficients were computed for modeled x-ray system spectra that are used in a number of new breast imaging applications. The reported values were found to be in excellent agreement when compared to published values. PMID:26348995

  3. Salivary gland acinar cells regenerate functional glandular structures in modified hydrogels

    NASA Astrophysics Data System (ADS)

    Pradhan, Swati

    Xerostomia, a condition resulting from irradiation of the head and neck, affects over 40,000 cancer patients each year in the United States. Direct radiation damage of the acinar cells that secrete fluid and protein results in salivary gland hypofunction. Present medical management for xerostomia for patients treated for upper respiratory cancer is largely ineffective. Patients who have survived their terminal diagnosis are often left with a diminished quality of life and are unable to enjoy the simple pleasures of eating and drinking. This project aims to ultimately reduce human suffering by developing a functional implantable artificial salivary gland. The goal was to create an extracellular matrix (ECM) modified hyaluronic acid (HA) based hydrogel culture system that allows for the growth and differentiation of salivary acinar cells into functional acini-like structures capable of secreting large amounts of protein and fluid unidirectionally and to ultimately engineer a functional artificial salivary gland that can be implanted into an animal model. A tissue collection protocol was established and salivary gland tissue was obtained from patients undergoing head and neck surgery. The tissue specimen was assessed by histology and immunohistochemistry to establish the phenotype of normal salivary gland cells including the native basement membranes. Hematoxylin and eosin staining confirmed normal glandular tissue structures including intercalated ducts, striated ducts and acini. alpha-Amylase and periodic acid schiff stain, used for structures with a high proportion of carbohydrate macromolecules, preferentially stained acinar cells in the tissue. Intercalated and striated duct structures were identified using cytokeratins 19 and 7 staining. Myoepithelial cells positive for cytokeratin 14 were found wrapped around the serous and mucous acini. Tight junction components including ZO-1 and E-cadherin were present between both ductal and acinar cells. Ductal and acinar

  4. Bringing Back Sweet (and Not so Sweet) Memories: The Cultural Politics of Memory, Hip-Hop, and Generational Identities

    ERIC Educational Resources Information Center

    Hill, Marc Lamont

    2009-01-01

    This article examines the salience of collective "memory" and "remembering" among a group of students in Hip-Hop Lit, a hip-hop centered English literature course that I co-taught at "Howard High School," an urban high school in the Northeastern United States. Specifically, this article examines the memory work that occurred within Hip-Hop Lit in…

  5. Digital breast tomosynthesis and digital mammography: A comparison of figures of merit for various average glandular doses

    NASA Astrophysics Data System (ADS)

    Kim, Ye-seul; Park, Hye-Suk; Park, SuJin; Kim, Hee-Joung; Choi, Jae-Gu; Choi, Young-Wook; Park, Jun-Ho; Lee, Jae-Jun

    2013-05-01

    Previous studies on the application of tomosynthesis to breast imaging have demonstrated the potential of digital breast tomosynthesis (DBT). DBT can improve the specificity of digital mammography (DM) through improved marginal visibility of lesions and early breast cancer detection for women with dense breasts. To investigate possible improvements in the accuracy of lesion detection with DBT systems as compared to DM, we conducted a quantitative evaluation by using simulated lesions embedded in a breast phantom. A prototype DBT and dedicated DM system were used in this study. For the DBT system, the average glandular dose (AGD) was calculated using a formalism that was a simple extension of mammography dosimetry. The DBT and the DM images were acquired with average glandular doses (AGDs) ranging from 1 to 4 mGy. To analyze the results objectively, we calculated metrics for in-plane lesion visibility in the form of the contrast-to-noise ratio for the in-focus plane from the DBT reconstruction image and from the craniocaudal (CC) image from the DM system. The imaging performance of DBT was quantitatively compared with that of DM in terms of the figure of merit. Although the DM showed better results in terms of the contrast-to-noise ratio (CNR) of the mass due to the reduced overlapping of tissue and lesion, an increase in breast thickness of over 3 cm increased the CNR of the mass with the DBT system. For microcalcification detection, the DBT system showed significantly higher CNR than the DM system and gave better predictions of the microcalcification size. We compared the performances of the DM and the DBT systems for various AGDs and breast thicknesses. In conclusion, the results indicate that the DBT systems can play an important role in the detection of masses or microcalcifications without severe compression.

  6. Proteomics of the human endometrial glandular epithelium and stroma from the proliferative and secretory phases of the menstrual cycle.

    PubMed

    Hood, Brian L; Liu, Baoquan; Alkhas, Addie; Shoji, Yutaka; Challa, Rusheeswar; Wang, Guisong; Ferguson, Susan; Oliver, Julie; Mitchell, Dave; Bateman, Nicholas W; Zahn, Christopher M; Hamilton, Chad A; Payson, Mark; Lessey, Bruce; Fazleabas, Asgerally T; Maxwell, G Larry; Conrads, Thomas P; Risinger, John I

    2015-04-01

    Despite its importance in reproductive biology and women's health, a detailed molecular-level understanding of the human endometrium is lacking. Indeed, no comprehensive studies have been undertaken to elucidate the important protein expression differences between the endometrial glandular epithelium and surrounding stroma during the proliferative and midsecretory phases of the menstrual cycle. We utilized laser microdissection to harvest epithelial cells and stromal compartments from proliferative and secretory premenopausal endometrial tissue and performed a global, quantitative mass spectrometry-based proteomics analysis. This analysis identified 1224 total proteins from epithelial cells, among which 318 were differentially abundant between the proliferative and secretory phases (q < 0.05), and 1005 proteins from the stromal compartments, 19 of which were differentially abundant between the phases (q < 0.05). Several proteins were chosen for validation by immunohistochemistry in an independent set of uterine tissues, including carboxypeptidase M, tenascin C, neprilysin, and ectonucleotide pyrophosphatase/phosphodiesterase family member 3 (ENPP3). ENPP3, which was elevated in epithelial glandular cells in the secretory phase, was confirmed to be elevated in midsecretory-phase baboon uterine lavage samples and also observed to have an N-linked glycosylated form that was not observed in the proliferative phase. This study provides a detailed view into the global proteomic alterations of the epithelial cells and stromal compartments of the cycling premenopausal endometrium. These proteomic alterations during endometrial remodeling provide a basis for numerous follow-up investigations on the function of these differentially regulated proteins and their role in reproductive biology and endometrial pathologies. PMID:25695723

  7. Cell proliferation, DNA repair, and p53 function are not required for programmed death of prostatic glandular cells induced by androgen ablation.

    PubMed Central

    Berges, R R; Furuya, Y; Remington, L; English, H F; Jacks, T; Isaacs, J T

    1993-01-01

    Androgen ablation induces programmed death of androgen-dependent prostatic glandular cells, resulting in fragmentation of their genomic DNA and the cells themselves into apoptotic bodies. Twenty percent of prostatic glandular cells undergo programmed death per day between day 2 and 5 after castration. During this same period, < 1% of prostatic glandular cells enter the S phase of the cell cycle, documenting that > 95% of these die in G0. During the programmed death of these G0 glandular cells, a futile DNA repair process is induced secondary to the DNA fragmentation. This futile DNA repair is not required, however, since inhibition of this process by > 90% with an appropriately timed hydroxy-urea dosing regimen had no effect upon the extent of the programmed death of these cells after castration. Likewise, p53 gene expression is not required since the same degree of cell death occurred in prostates and seminal vesicles after castration of wild-type and p53-deficient mice. PMID:8415631

  8. Partial processing satellite relays for frequency-hop antijam communications

    NASA Astrophysics Data System (ADS)

    Sussman, S. M.; Kotiveeriah, P.

    1982-08-01

    Jamming effects on the uplink and downlink are combined to derive the earth station-to-earth station performance. In the linear dehop-rehop transponder (DRT), the retransmitted uplink noise and jamming for various ratios of relay bandwidth to data rate are taken into account, and a new end-to-end SNR relation is obtained. The symbol regenerative processor (SRP) analysis is based on the appropriate combining of uplink and downlink error probabilities to yield the end-to-end error probability. The jammer is assumed to employ either full-band noise or optimum partial band jamming, and several combinations of these two jamming strategies are evaluated. The relationship between uplink and downlink SNR are obtained for specified end-to-end SNR or error probability, and drawn between the DRT and the SRP. The analysis treats M-ary orthogonal frequency shift typing with incoherent combining and detection of multiple frequency hops per symbol.

  9. Giant magnetoresistance in the variable-range hopping regime

    SciTech Connect

    Ioffe, L. B.; Spivak, B. Z.

    2013-09-15

    We predict the universal power-law dependence of the localization length on the magnetic field in the strongly localized regime. This effect is due to the orbital quantum interference. Physically, this dependence shows up in an anomalously large negative magnetoresistance in the hopping regime. The reason for the universality is that the problem of the electron tunneling in a random media belongs to the same universality class as the directed polymer problem even in the case of wave functions of random sign. We present numerical simulations that prove this conjecture. We discuss the existing experiments that show anomalously large magnetoresistance. We also discuss the role of localized spins in real materials and the spin polarizing effect of the magnetic field.

  10. Improving range resolution with a frequency-hopping technique

    NASA Technical Reports Server (NTRS)

    Stitt, G. R.; Bowhill, S. A.

    1986-01-01

    Range resolution of a conventional pulsed Doppler radar is determined by the scattering volume defined by the transmitted pulse shape. To increase the resolution, the length of the pulse must be reduced. Reducing the pulse length also reduces the transmitted power and hense the signal to noise ratio unless the peak power capability of the transmitter is greatly increased. Improved range resolution may also be attained through the use of various pulse coding methods, but such methods are sometimes difficult to implement from a hardware standpoint. The frequency-hopping (F-H) technique described increases the range resolution of pulse Doppler MST (mesosphere stratosphere troposphere) radar without the need for extensive modifications to the radar transmitter. This technique consists of sending a repeated sequence of pulses, each pulse in the sequence being transmitted at a unique radio frequency that is under the control of a microcomputer. This technique is discussed along with other radar parameters.

  11. Giant magnetoresistance in the variable-range hopping regime

    NASA Astrophysics Data System (ADS)

    Ioffe, L. B.; Spivak, B. Z.

    2013-09-01

    We predict the universal power-law dependence of the localization length on the magnetic field in the strongly localized regime. This effect is due to the orbital quantum interference. Physically, this dependence shows up in an anomalously large negative magnetoresistance in the hopping regime. The reason for the universality is that the problem of the electron tunneling in a random media belongs to the same universality class as the directed polymer problem even in the case of wave functions of random sign. We present numerical simulations that prove this conjecture. We discuss the existing experiments that show anomalously large magnetoresistance. We also discuss the role of localized spins in real materials and the spin polarizing effect of the magnetic field.

  12. Systematic network coding for two-hop lossy transmissions

    NASA Astrophysics Data System (ADS)

    Li, Ye; Blostein, Steven; Chan, Wai-Yip

    2015-12-01

    In this paper, we consider network transmissions over a single or multiple parallel two-hop lossy paths. These scenarios occur in applications such as sensor networks or WiFi offloading. Random linear network coding (RLNC), where previously received packets are re-encoded at intermediate nodes and forwarded, is known to be a capacity-achieving approach for these networks. However, a major drawback of RLNC is its high encoding and decoding complexity. In this work, a systematic network coding method is proposed. We show through both analysis and simulation that the proposed method achieves higher end-to-end rate as well as lower computational cost than RLNC for finite field sizes and finite-sized packet transmissions.

  13. Conductivities and Seebeck coefficients of boron carbides: Softening bipolaron hopping

    NASA Astrophysics Data System (ADS)

    Aselage, T. L.; Emin, D.; McCready, S. S.

    2001-08-01

    The electrical conductivities and Seebeck coefficients of boron carbides B12+xC3-x with 0.06<~x<~1.7 have been measured from 8 K to as high as 1750 K. At high temperature, the temperature dependence of the conductivities is Arrhenius and the activation energy, ~0.16 eV, is independent of the carbon concentration. The preexponential factors of the conductivity exhibit a nonmonotonic dependence on x, peaking near x=1. These results are consistent with a previously proposed model based on holes forming singlet bipolarons on the boron carbide B11C icosahedra. At low temperature, the boron carbide conductivities are non-Arrhenius with a temperature dependence that is a strong function of the composition x. This strong sensitivity to composition indicates that percolation effects, arising from boron carbides having carbon atoms in inequivalent locations, influence the conductivity at low temperature. With x holes per unit cell, boron carbides have very large Seebeck coefficients that depend only weakly on x. The magnitudes and temperature dependences of the Seebeck coefficients are consistent with large contributions from carrier-induced softening of local vibrations. Softening effects can be exceptionally large when singlet bipolarons are stabilized among degenerate electronic energy levels by their softening of symmetry-breaking vibrations: ``softening bipolarons.'' The boron carbide transport properties are generally consistent with those expected of softening bipolarons. Finally, two high-temperature effects are observed in the boron carbide conductivities. The conductivities of samples having high carrier densities, x~1, are suppressed above 700 K. This suppression can arise when the rapid hopping of nearby carriers disrupts the energy coincidence required for a carrier's hop. At even higher temperatures, a sharp increase in the boron carbide conductivities (σ~T4) suggests a radiation-induced excitation of mobile charge carriers.

  14. Understanding hopping transport and thermoelectric properties of conducting polymers

    NASA Astrophysics Data System (ADS)

    Ihnatsenka, S.; Crispin, X.; Zozoulenko, I. V.

    2015-07-01

    We calculate the conductivity σ and the Seebeck coefficient S for the phonon-assisted hopping transport in conducting polymers poly(3,4-ethylenedioxythiophene) or PEDOT, experimentally studied by Bubnova et al. [J. Am. Chem. Soc. 134, 16456 (2012)], 10.1021/ja305188r. We use the Monte Carlo technique as well as the semianalytical approach based on the transport energy concept. We demonstrate that both approaches show a good qualitative agreement for the concentration dependence of σ and S . At the same time, we find that the semianalytical approach is not in a position to describe the temperature dependence of the conductivity. We find that both Gaussian and exponential density of states (DOS) reproduce rather well the experimental data for the concentration dependence of σ and S giving similar fitting parameters of the theory. The obtained parameters correspond to a hopping model of localized quasiparticles extending over 2-3 monomer units with typical jumps over a distance of 3-4 units. The energetic disorder (broadening of the DOS) is estimated to be 0.1 eV. Using the Monte Carlo calculation we reproduce the activation behavior of the conductivity with the calculated activation energy close to the experimentally observed one. We find that for a low carrier concentration a number of free carriers contributing to the transport deviates strongly from the measured oxidation level. Possible reasons for this behavior are discussed. We also study the effect of the dimensionality on the charge transport by calculating the Seebeck coefficient and the conductivity for the cases of three-, two-, and one-dimensional motion.

  15. Coding for frequency hopped spread spectrum satellite communications

    NASA Astrophysics Data System (ADS)

    Bhargava, Vijay K.; Wang, Qiang; Blake, Ian F.; Li, Gang; Gulliver, T. Aaron; Dravnieks, Olaf

    1990-04-01

    Work aimed at improving the jamming resistance of satellite communications is reviewed. The performance of Reed-Solomon (RS) error correcting codes with slow frequency hopped (SFH) differential phase shift keying (DPSK) signalling is analyzed and evaluated under worst case partial band noise and worst case multitone jamming. A representative set of performance curves is shown. Recommendation on the choice of RS code parameters is given. Two in-hop jamming cancellation schemes for SFH/DPSK systems are proposed. One scheme is based on balanced coding; the other one uses notch filter to cancel jamming tone. The performance of both schemes is illustrated. It is shown that both schemes can work well under certain conditions. Basic principles and techniques for designing interleavers are presented. Block, convolution, and the more recent helical interleavers are considered. The trade-off between diversity and coding for spread spectrum systems, where a low code rate is anticipated, is discussed. An error correction scheme is presented for an M-ary symmetric channel (MSC) characterized by a large error probability (Pe). The value of Pe can be near, but smaller than 1-1/M, for which the channel capacity is zero. Such a large Pe may occur, for example, in a jamming environment. Monte-Carlo simulation results are presented. For the binary symmetric channel (BSC), it is shown that the overall code rate is larger than 0.6 R sub 0, where R sub 0 is the cutoff rate of the channel. For BSC and a large diversity order (m), a method is presented for BER (bit error rate) approximation on the central limit theorem.

  16. Coupled catastrophes: sudden shifts cascade and hop among interdependent systems.

    PubMed

    Brummitt, Charles D; Barnett, George; D'Souza, Raissa M

    2015-11-01

    An important challenge in several disciplines is to understand how sudden changes can propagate among coupled systems. Examples include the synchronization of business cycles, population collapse in patchy ecosystems, markets shifting to a new technology platform, collapses in prices and in confidence in financial markets, and protests erupting in multiple countries. A number of mathematical models of these phenomena have multiple equilibria separated by saddle-node bifurcations. We study this behaviour in its normal form as fast-slow ordinary differential equations. In our model, a system consists of multiple subsystems, such as countries in the global economy or patches of an ecosystem. Each subsystem is described by a scalar quantity, such as economic output or population, that undergoes sudden changes via saddle-node bifurcations. The subsystems are coupled via their scalar quantity (e.g. trade couples economic output; diffusion couples populations); that coupling moves the locations of their bifurcations. The model demonstrates two ways in which sudden changes can propagate: they can cascade (one causing the next), or they can hop over subsystems. The latter is absent from classic models of cascades. For an application, we study the Arab Spring protests. After connecting the model to sociological theories that have bistability, we use socioeconomic data to estimate relative proximities to tipping points and Facebook data to estimate couplings among countries. We find that although protests tend to spread locally, they also seem to 'hop' over countries, like in the stylized model; this result highlights a new class of temporal motifs in longitudinal network datasets. PMID:26559684

  17. Coupled catastrophes: sudden shifts cascade and hop among interdependent systems

    PubMed Central

    Barnett, George; D'Souza, Raissa M.

    2015-01-01

    An important challenge in several disciplines is to understand how sudden changes can propagate among coupled systems. Examples include the synchronization of business cycles, population collapse in patchy ecosystems, markets shifting to a new technology platform, collapses in prices and in confidence in financial markets, and protests erupting in multiple countries. A number of mathematical models of these phenomena have multiple equilibria separated by saddle-node bifurcations. We study this behaviour in its normal form as fast–slow ordinary differential equations. In our model, a system consists of multiple subsystems, such as countries in the global economy or patches of an ecosystem. Each subsystem is described by a scalar quantity, such as economic output or population, that undergoes sudden changes via saddle-node bifurcations. The subsystems are coupled via their scalar quantity (e.g. trade couples economic output; diffusion couples populations); that coupling moves the locations of their bifurcations. The model demonstrates two ways in which sudden changes can propagate: they can cascade (one causing the next), or they can hop over subsystems. The latter is absent from classic models of cascades. For an application, we study the Arab Spring protests. After connecting the model to sociological theories that have bistability, we use socioeconomic data to estimate relative proximities to tipping points and Facebook data to estimate couplings among countries. We find that although protests tend to spread locally, they also seem to ‘hop' over countries, like in the stylized model; this result highlights a new class of temporal motifs in longitudinal network datasets. PMID:26559684

  18. Histochemical evidence of β-chitin in parapodial glandular organs and tubes of Spiophanes (Annelida, Sedentaria: Spionidae), and first studies on selected Annelida.

    PubMed

    Guggolz, Theresa; Henne, Stephan; Politi, Yael; Schütz, Roman; Mašić, Admir; Müller, Carsten H G; Meißner, Karin

    2015-12-01

    A generic character of the genus Spiophanes (Annelida, Sedentaria: Spionidae) is the presence of parapodial glandular organs. Parapodial glandular organs in Spiophanes species include secretory cells with cup-shaped microvilli, similar to those present in deep-sea inhabiting vestimentiferans and frenulate Siboglinidae. These cells are supposed to secrete β-chitin for tube-building. In this study, transverse histological and/or ultrathin sections of parapodial glandular organs and tubes of Spiophanes spp. as well as of Glandulospio orestes (Spionidae) and Owenia fusiformis (Oweniidae) were examined. Fluorescent markers together with confocal laser scanning microscopy, and Raman spectroscopy were used to detect chitin in the parapodial glandular organs of Spiophanes and/or in the glands of Owenia and Glandulospio. Tubes of these taxa were tested for chitin to elucidate the use of it for tube-building. The examinations revealed a distinct labelling of the gland contents. Raman spectroscopy documented the presence of β-chitin in both gland types of Spiophanes. The tubes of Spiophanes were found to have a grid-like structure that seems to be built with this β-chitin. Tests of tubes of Dipolydora quadrilobata (Spionidae) for chitin were negative. However, the results of our study provide strong evidence that Spiophanes species, O. fusiformis and probably also G. orestes produce chitin and supposedly use it for tube-building. This implies that the production of chitin and its use as a constituent part of tube-building is more widespread among polychaetes as yet known. The histochemical data presented in this study support previous assumptions inferring homology of parapodial glandular organs of Spionidae and Siboglinidae based on ultrastructure. Furthermore, transmission electron microscopy-based evidence of secretory cells with nail-headed microvilli in O. fusiformis suggests homology of parapodial grandular organs across annelids including Sipuncula. PMID:26291785

  19. Increased secretion of glandular-kallikrein in the bronchial washings induced by intravenous injection of leukotriene C4 in guinea-pigs.

    PubMed Central

    Jin, H. Y.; Katori, M.; Majima, M.; Sunahara, N.

    1992-01-01

    1. Intravenous administration of leukotriene C4 (LTC4) and LTD4 (1-10 nmol kg-1) caused a dose-dependent increase in secretion of glandular-kallikrein in the bronchial washings of guinea-pigs, as measured by cleavage of a synthetic substrate and the formation of kinin. LTC4 was more potent than LTD4 and pilocarpine was much less potent than peptide leukotrienes on a molecular basis. 2. The increases in levels of glandular-kallikrein in the bronchial washings that were induced by LTC4 (3 nmol kg-1, i.v.) were almost completely inhibited by pretreatment with an antagonist of leukotrienes (ONO-1078), with an antagonist of thromboxane (S-1452), with an inhibitor of thromboxane synthetase (OKY-046), with indomethacin, with atropine or with scopolamine. These results indicate that the LTC4-induced increase in levels of glandular-kallikrein may have been mediated by the formation of thromboxane and the release of acetylcholine. 3. The increases in levels of glandular-kallikrein in the bronchial washings induced by STA2 (20 pmol kg-1, i.v.), a stable analogue of thromboxane A2, were completely blocked by pretreatment with atropine, whereas increases induced by pilocarpine (41 mumol kg-1, i.v.) were not blocked by pretreatment with indomethacin, although such increases were inhibited by atropine. This result indicates that secretion of kallikrein stimulated by LTC4 may have been mediated by the successive formation of thromboxane A2 and release of acetylcholine. 4. Intravenous administration of bradykinin (3-30 nmol kg-1) caused a dose-dependent increase in levels of glandular-kallikrein in the bronchial washings. This increase was completely inhibited by pretreatment with atropine, with indomethacin or with an antagonist of thromboxane.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1628150

  20. Hopping of an impurity defect in ion crystals in linear traps

    NASA Astrophysics Data System (ADS)

    Liang, J.; Haljan, P. C.

    2011-06-01

    Laser-cooled arrays or crystals of Yb171+ ions containing a single impurity, Yb172+ isotope, are confined in a linear radio-frequency Paul trap. Site-to-site hopping of the impurity ion, distinguished by a lack of fluorescence, is studied as a function of the Yb171+ laser-cooling parameters and as a function of the anisotropy of the trapping potential. Imaging of the independently resolved crystal sites permits the extraction of the impurity’s hopping trajectory, from which the dwell times at a given site can be obtained as well as the spatial distribution of hopping rate and hopping destination. The onset of rapid hopping is found to occur at average thermal energies approaching a significant fraction of the Coulomb potential energy. Furthermore, the hopping rate is enhanced at trap anisotropies near the critical value for the structural phase transition to a two-dimensional zigzag phase. Finally, the hopping mobility of the impurity ion is observed to be highest near the center of the crystal, which may have an intrinsic cause related to the crystal structure and dynamics near the zigzag transition.

  1. RILP interacts with HOPS complex via VPS41 subunit to regulate endocytic trafficking

    PubMed Central

    Lin, Xiaosi; Yang, Ting; Wang, Shicong; Wang, Zhen; Yun, Ye; Sun, Lixiang; Zhou, Yunhe; Xu, Xiaohui; Akazawa, Chihiro; Hong, Wanjin; Wang, Tuanlao

    2014-01-01

    The HOPS complex serves as a tethering complex with GEF activity for Ypt7p in yeast to regulate late endosomal membrane maturation. While the role of HOPS complex is well established in yeast cells, its functional and mechanistic aspects in mammalian cells are less well defined. In this study, we report that RILP, a downstream effector of Rab7, interacts with HOPS complex and recruits HOPS subunits to the late endosomal compartment. Structurally, the amino-terminal portion of RILP interacts with HOPS complex. Unexpectedly, this interaction is independent of Rab7. VPS41 subunit of HOPS complex was defined to be the major partner for interacting with RILP. The carboxyl-terminal region of VPS41 was mapped to be responsible for the interaction. Functionally, either depletion of VPS41 by shRNA or overexpression of VPS41 C-terminal half retarded EGF-induced degradation of EGFR. These results suggest that interaction of RILP with HOPS complex via VPS41 plays a role in endocytic trafficking of EGFR. PMID:25445562

  2. Cytotoxic effect of commercial Humulus lupulus L. (hop) preparations - In comparison to its metabolomic fingerprint.

    PubMed

    Farag, Mohamed A; Wessjohann, Ludger A

    2013-07-01

    Hops (Humulus lupulus L. Cannabaceae) is an economically important crop, that has drawn more attention in recent years due to its potential pharmaceutical applications. Bitter acids (prenylated polyketides) and prenylflavonoids are the primary phytochemical components that account for hops resins medicinal value. We have previously reported on utilizing untargeted NMR and MS metabolomics for analysis of 13 hops cultivars, revealing for differences in α- versus β-bitter acids composition in derived resins. In this study, effect of ratios of bitter α- to β-acids in hop resins to cytotoxicity of hop resins was investigated. In vitro cell culture assays revealed that β-acids were more effective than α-acids in growth inhibition of PC3 and HT29 cancer cell lines. Nevertheless, hop resins enriched in β-acids showed comparable growth inhibition patterns to α-enriched resins and suggesting that bioactivity may not be easily predicted by metabolomics and/or gross metabolic profiling in hops. PMID:25685448

  3. High-throughput genotyping of hop (Humulus lupulus L.) utilising diversity arrays technology (DArT).

    PubMed

    Howard, E L; Whittock, S P; Jakše, J; Carling, J; Matthews, P D; Probasco, G; Henning, J A; Darby, P; Cerenak, A; Javornik, B; Kilian, A; Koutoulis, A

    2011-05-01

    Implementation of molecular methods in hop (Humulus lupulus L.) breeding is dependent on the availability of sizeable numbers of polymorphic markers and a comprehensive understanding of genetic variation. However, use of molecular marker technology is limited due to expense, time inefficiency, laborious methodology and dependence on DNA sequence information. Diversity arrays technology (DArT) is a high-throughput cost-effective method for the discovery of large numbers of quality polymorphic markers without reliance on DNA sequence information. This study is the first to utilise DArT for hop genotyping, identifying 730 polymorphic markers from 92 hop accessions. The marker quality was high and similar to the quality of DArT markers previously generated for other species; although percentage polymorphism and polymorphism information content (PIC) were lower than in previous studies deploying other marker systems in hop. Genetic relationships in hop illustrated by DArT in this study coincide with knowledge generated using alternate methods. Several statistical analyses separated the hop accessions into genetically differentiated North American and European groupings, with hybrids between the two groups clearly distinguishable. Levels of genetic diversity were similar in the North American and European groups, but higher in the hybrid group. The markers produced from this time and cost-efficient genotyping tool will be a valuable resource for numerous applications in hop breeding and genetics studies, such as mapping, marker-assisted selection, genetic identity testing, guidance in the maintenance of genetic diversity and the directed breeding of superior cultivars. PMID:21243330

  4. Cytotoxic effect of commercial Humulus lupulus L. (hop) preparations – In comparison to its metabolomic fingerprint

    PubMed Central

    Farag, Mohamed A.; Wessjohann, Ludger A.

    2012-01-01

    Hops (Humulus lupulus L. Cannabaceae) is an economically important crop, that has drawn more attention in recent years due to its potential pharmaceutical applications. Bitter acids (prenylated polyketides) and prenylflavonoids are the primary phytochemical components that account for hops resins medicinal value. We have previously reported on utilizing untargeted NMR and MS metabolomics for analysis of 13 hops cultivars, revealing for differences in α- versus β-bitter acids composition in derived resins. In this study, effect of ratios of bitter α- to β-acids in hop resins to cytotoxicity of hop resins was investigated. In vitro cell culture assays revealed that β-acids were more effective than α-acids in growth inhibition of PC3 and HT29 cancer cell lines. Nevertheless, hop resins enriched in β-acids showed comparable growth inhibition patterns to α-enriched resins and suggesting that bioactivity may not be easily predicted by metabolomics and/or gross metabolic profiling in hops. PMID:25685448

  5. Vibrational spectroscopy and chemometrics for rapid, quantitative analysis of bitter acids in hops (Humulus lupulus).

    PubMed

    Killeen, Daniel P; Andersen, David H; Beatson, Ron A; Gordon, Keith C; Perry, Nigel B

    2014-12-31

    Hops, Humulus lupulus, are grown worldwide for use in the brewing industry to impart characteristic flavor and aroma to finished beer. Breeders produce many varietal crosses with the aim of improving and diversifying commercial hops varieties. The large number of crosses critical to a successful breeding program imposes high demands on the supporting chemical analytical laboratories. With the aim of reducing the analysis time associated with hops breeding, quantitative partial least-squares regression (PLS-R) models have been produced, relating reference data acquired by the industrial standard HPLC and UV methods, to vibrational spectra of the same, chemically diverse hops sample set. These models, produced from rapidly acquired infrared (IR), near-infrared (NIR), and Raman spectra, were appraised using standard statistical metrics. Results demonstrated that all three spectroscopic methods could be used for screening hops for α-acid, total bitter acids, and cohumulone concentrations in powdered hops. Models generated from Raman and IR spectra also showed potential for use in screening hops varieties for xanthohumol concentrations. NIR analysis was performed using both a standard benchtop spectrometer and a portable NIR spectrometer, with comparable results obtained by both instruments. Finally, some important vibrational features of cohumulone, colupulone, and xanthohumol were assigned using DFT calculations, which allow more insightful interpretation of PLS-R latent variable plots. PMID:25485767

  6. Hop, an active Mutator-like element in the genome of the fungus Fusarium oxysporum.

    PubMed

    Chalvet, Fabienne; Grimaldi, Christine; Kaper, Fiona; Langin, Thierry; Daboussi, Marie-Josée

    2003-08-01

    A new type of active DNA transposon has been identified in the genome of Fusarium oxysporum by its transposition into the niaD target gene. Two insertions within the final exon, in opposite orientations at the same nucleotide site, have been characterized. These elements, called Hop, are 3,299 bp long, with perfect terminal inverted repeats (TIRs) of 99 bp. The sequencing of genomic copies reveals a 9-bp target site duplication and no apparent sequence specificity at the insertion sites. The sequencing of a cDNA indicates that Hop does not contain an intron and encodes a putative transposase of 836 amino acids. The structural features (length, TIRs size, and 9-bp duplication), together with the presence of conserved domains in the transposase, strongly suggest that Hop is a Mutator-like element (MULE). Hop is thus the first active member of this family found beyond plants. The high rate of excision observed indicates that Hop is very active and thus represents a promising efficient tagging system for the isolation of fungal genes. The distribution of Hop elements within the Fusarium genus revealed that they are present in different species, suggesting that related elements could be present in other fungal genomes. In fact, Hop-related sequences have been identified in the survey of the entire genome sequence of three other ascomycetes, Magnaporthe grisea, Neurospora crassa, and Aspergillus fumigatus. PMID:12777515

  7. Standardization of Weed Pollen Extracts, Japanese Hop and Mugwort, in Korea

    PubMed Central

    Jeong, Kyoung Yong; Son, Mina; Choi, Soo-Young; Park, Kyung Hee; Park, Hye Jung; Hong, Chein-Soo; Lee, Jae-Hyun

    2016-01-01

    Purpose Japanese hop (Humulus spp.) and mugwort (Artemisia spp.) are notable causes of autumn pollinosis in East Asia. However, Japanese hop and mugwort pollen extracts, which are widely used for the diagnosis, have not been standardized. This study was performed to standardize Japanese hop and mugwort pollen extracts. Materials and Methods Allergen extracts were prepared in a standardized way using locally collected Humulus japonicus and purchased Artemisia vulgaris pollens. The immunoglobulin E (IgE) reactivities of prepared extracts were compared with commercial extracts via IgE immunoblotting and inhibition analyses. Intradermal skin tests were performed to determine the bioequivalent allergy unit (BAU). Results The IgE reactive components of the extracts via IgE immunoblotting were similar to those of commercial extracts. A 11-kDa allergen showed the strongest IgE reactivity in Japanese hop, as did a 28-kDa allergen in mugwort pollen extracts. Allergenic potencies of the investigatory Japanese hop and mugwort extracts were essentially indistinguishable from the commercial ones. Sums of erythema of 50 mm by the intradermal skin test (ΣED50) were calculated to be 14.4th and 13.6th three-fold dilutions for Japanese hop and mugwort extracts, respectively. Therefore, the allergenic activity of the prepared extracts was 90827.4 BAU/mg for Japanese hop and 34412 BAU/mg for mugwort. Conclusion We produced Japanese hop and mugwort pollen extracts using a standardized method. Standardized Japanese hop and mugwort pollen extracts will facilitate the production of improved diagnostic and immunotherapeutic reagents. PMID:26847293

  8. Pseudomonas syringae Effector HopF2 Suppresses Arabidopsis Immunity by Targeting BAK1

    PubMed Central

    Zhou, Jinggeng; Wu, Shujing; Chen, Xin; Liu, Chenglong; Sheen, Jen; Shan, Libo; He, Ping

    2014-01-01

    Summary Pseudomonas syringae delivers a plethora of effector proteins into host cells to sabotage immune responses and modulate physiology to favor infection. We have previously shown that P. syringae pv. tomato DC3000 effector HopF2 suppresses Arabidopsis innate immunity triggered by multiple microbe-associated molecular patterns (MAMP) at the plasma membrane. We show here that HopF2 possesses distinct mechanisms in the suppression of two branches of MAMP-activated MAP kinase (MPK) cascades. Besides blocking MKK5 (MPK kinase 5) activation in the MEKK1/MEKKs-MKK4/5-MPK3/6 cascade, HopF2 targets additional component(s) upstream of MEKK1 in the MEKK1-MKK1/2-MPK4 cascade and plasma membrane-localized receptor-like cytoplasmic kinase BIK1 and its homologs. We further show that HopF2 directly targets BAK1, a plasma membrane-localized receptor-like kinase involved in multiple MAMP signaling. The interaction between BAK1 and HopF2 or two other P. syringae effectors AvrPto and AvrPtoB, was confirmed in vivo and in vitro. Consistent with BAK1 as a physiological target of AvrPto, AvrPtoB and HopF2, the strong growth defects or lethality associated with ectopic expression of these effectors in wild-type Arabidopsis transgenic plants were largely alleviated in bak1 mutant plants. Thus, our results provide genetic evidence to further support that BAK1 is a physiological target of AvrPto, AvrPtoB and HopF2. Identification of BAK1 as an additional target of HopF2 virulence not only explains HopF2 suppression of multiple MAMP signaling at the plasma membrane, but also supports the notion that pathogen virulence effectors act through multiple targets in host cells. PMID:24237140

  9. Animal galloping and human hopping: an energetics and biomechanics laboratory exercise

    PubMed Central

    Lindstedt, Stan L.; Mineo, Patrick M.

    2013-01-01

    This laboratory exercise demonstrates fundamental principles of mammalian locomotion. It provides opportunities to interrogate aspects of locomotion from biomechanics to energetics to body size scaling. It has the added benefit of having results with robust signal to noise so that students will have success even if not “meticulous” in attention to detail. First, using respirometry, students measure the energetic cost of hopping at a “preferred” hop frequency. This is followed by hopping at an imposed frequency half of the preferred. By measuring the O2 uptake and work done with each hop, students calculate mechanical efficiency. Lessons learned from this laboratory include 1) that the metabolic cost per hop at half of the preferred frequency is nearly double the cost at the preferred frequency; 2) that when a person is forced to hop at half of their preferred frequency, the mechanical efficiency is nearly that predicted for muscle but is much higher at the preferred frequency; 3) that the preferred hop frequency is strongly body size dependent; and 4) that the hop frequency of a human is nearly identical to the galloping frequency predicted for a quadruped of our size. Together, these exercises demonstrate that humans store and recover elastic recoil potential energy when hopping but that energetic savings are highly frequency dependent. This stride frequency is dependent on body size such that frequency is likely chosen to maximize this function. Finally, by requiring students to make quantitative solutions using appropriate units and dimensions of the physical variables, these exercises sharpen analytic and quantitative skills. PMID:24292916

  10. The Pseudomonas syringae effector HopF2 suppresses Arabidopsis immunity by targeting BAK1.

    PubMed

    Zhou, Jinggeng; Wu, Shujing; Chen, Xin; Liu, Chenglong; Sheen, Jen; Shan, Libo; He, Ping

    2014-01-01

    Pseudomonas syringae delivers a plethora of effector proteins into host cells to sabotage immune responses and modulate physiology to favor infection. The P. syringae pv. tomato DC3000 effector HopF2 suppresses Arabidopsis innate immunity triggered by multiple microbe-associated molecular patterns (MAMP) at the plasma membrane. We show here that HopF2 possesses distinct mechanisms for suppression of two branches of MAMP-activated MAP kinase (MAPK) cascades. In addition to blocking MKK5 (MAPK kinase 5) activation in the MEKK1 (MAPK kinase kinase 1)/MEKKs-MKK4/5-MPK3/6 cascade, HopF2 targets additional component(s) upstream of MEKK1 in the MEKK1-MKK1/2-MPK4 cascade and the plasma membrane-localized receptor-like cytoplasmic kinase BIK1 and its homologs. We further show that HopF2 directly targets BAK1, a plasma membrane-localized receptor-like kinase that is involved in multiple MAMP signaling. The interaction between BAK1 and HopF2 and between two other P. syringae effectors, AvrPto and AvrPtoB, was confirmed in vivo and in vitro. Consistent with BAK1 as a physiological target of AvrPto, AvrPtoB and HopF2, the strong growth defects or lethality associated with ectopic expression of these effectors in wild-type Arabidopsis transgenic plants were largely alleviated in bak1 mutant plants. Thus, our results provide genetic evidence to show that BAK1 is a physiological target of AvrPto, AvrPtoB and HopF2. Identification of BAK1 as an additional target of HopF2 virulence not only explains HopF2 suppression of multiple MAMP signaling at the plasma membrane, but also supports the notion that pathogen virulence effectors act through multiple targets in host cells. PMID:24237140

  11. Falicov-Kimball model extended by pair hopping of d-electrons

    NASA Astrophysics Data System (ADS)

    Ghosh, N. K.; Mukherjee, P.

    2016-05-01

    The effect of the pair hopping of d-electrons has been examined in an exact diagonalization techniqueon a four-site square cluster using extended Falicov-Kimball model. This hopping interaction shifts the critical f-level energy (Ec) at which valence transition occurs. Sharp peaks are observed in the specific heat curves and pair hopping decreases the peak height indicating a reduction in the number of density of states. Antiferromagnetic ordering as well as Curie-like behavior has been observed in the spin susceptibility (χ) characteristics.

  12. High temperature electrical conductivity due to small polaron hopping motion in DNA molecules

    NASA Astrophysics Data System (ADS)

    Triberis, G. P.; Karavolas, V. C.; Simserides, C. D.

    2005-01-01

    We present a small polaron hopping model to interpret the high-temperature electrical conductivity measured along the DNA molecules. The model takes into account the one-dimensional character of the system and the presence of disorder in the DNA double helix. The experimental data for the lambda phage DNA (λ-DNA) and the poly(dA)-poly(dT) DNA follow nicely the theoretically predicted behavior leading to realistic values of the maximum hopping distances supporting the idea of multiphonon-assisted hopping of small polarons between next nearest neighbors of the DNA molecular "wire".

  13. Structure and properties of the glandular surface in the digestive zone of the pitcher in the carnivorous plant Nepenthes ventrata and its role in insect trapping and retention.

    PubMed

    Gorb, Elena; Kastner, Victoria; Peressadko, Andrei; Arzt, Eduard; Gaume, Laurence; Rowe, Nick; Gorb, Stanislav

    2004-08-01

    Carnivorous plants of the genus Nepenthes grow in nutrient-poor habitats and have evolved specialised trapping organs, known as pitchers. These are composed of different surface zones serving the functions of attraction, capture and digestion of insects, which represent a main source of nitrogen. To investigate the role of the glandular digestive zone in the trapping mechanism of the pitcher, structural, mechanical and physico-chemical studies were applied to N. ventrata and combined with insect behavioural experiments. It was found that the glandular surface is microscopically rough since it is regularly structured with multicellular glands situated in epidermal depressions. The presence of downward-directed 'hoods' over the upper part of glands and sloped depressions in the proximal direction of the pitcher causes a marked anisotropy of the surface. The glandular zone surface is composed of relatively stiff material (Young's modulus, 637.19+/-213.44 kPa). It is not homogeneous, in terms of adhesive properties, and contains numerous areas without adhesion as well as adhesive areas differing greatly in tenacity values (range, 1.39-28.24 kPa). The surface is readily wettable with water (contact angle, 31.9-36.0 degrees C) and has a high surface free energy (56.84-61.93 mN m(-1)) with a relatively high polar component (33.09-52.70 mN m(-1)). To examine the effect of the glandular secretion on attachment systems of insects having hairy and smooth adhesive pads, forces generated on different surfaces by Calliphora vicina flies and Pyrrhocoris apterus bugs, respectively, were measured. Flies attached equally well to both fresh and air-dried glandular surfaces whereas bugs generated a significantly lower force on the fresh glandular surface compared with the air-dried one. It is assumed that the contribution of the glandular surface to insect retention, due to its effect on insect attachment, differs depending on insect weight and the type of insect attachment system

  14. Plasmodium falciparum Hop (PfHop) Interacts with the Hsp70 Chaperone in a Nucleotide-Dependent Fashion and Exhibits Ligand Selectivity.

    PubMed

    Zininga, Tawanda; Makumire, Stanely; Gitau, Grace Wairimu; Njunge, James M; Pooe, Ofentse Jacob; Klimek, Hanna; Scheurr, Robina; Raifer, Hartmann; Prinsloo, Earl; Przyborski, Jude M; Hoppe, Heinrich; Shonhai, Addmore

    2015-01-01

    Heat shock proteins (Hsps) play an important role in the development and pathogenicity of malaria parasites. One of the most prominent functions of Hsps is to facilitate the folding of other proteins. Hsps are thought to play a crucial role when malaria parasites invade their host cells and during their subsequent development in hepatocytes and red blood cells. It is thought that Hsps maintain proteostasis under the unfavourable conditions that malaria parasites encounter in the host environment. Although heat shock protein 70 (Hsp70) is capable of independent folding of some proteins, its functional cooperation with heat shock protein 90 (Hsp90) facilitates folding of some proteins such as kinases and steroid hormone receptors into their fully functional forms. The cooperation of Hsp70 and Hsp90 occurs through an adaptor protein called Hsp70-Hsp90 organising protein (Hop). We previously characterised the Hop protein from Plasmodium falciparum (PfHop). We observed that the protein co-localised with the cytosol-localised chaperones, PfHsp70-1 and PfHsp90 at the blood stages of the malaria parasite. In the current study, we demonstrated that PfHop is a stress-inducible protein. We further explored the direct interaction between PfHop and PfHsp70-1 using far Western and surface plasmon resonance (SPR) analyses. The interaction of the two proteins was further validated by co-immunoprecipitation studies. We observed that PfHop and PfHsp70-1 associate in the absence and presence of either ATP or ADP. However, ADP appears to promote the association of the two proteins better than ATP. In addition, we investigated the specific interaction between PfHop TPR subdomains and PfHsp70-1/ PfHsp90, using a split-GFP approach. This method allowed us to observe that TPR1 and TPR2B subdomains of PfHop bind preferentially to the C-terminus of PfHsp70-1 compared to PfHsp90. Conversely, the TPR2A motif preferentially interacted with the C-terminus of PfHsp90. Finally, we observed that

  15. Plasmodium falciparum Hop (PfHop) Interacts with the Hsp70 Chaperone in a Nucleotide-Dependent Fashion and Exhibits Ligand Selectivity

    PubMed Central

    Zininga, Tawanda; Makumire, Stanely; Gitau, Grace Wairimu; Njunge, James M.; Pooe, Ofentse Jacob; Klimek, Hanna; Scheurr, Robina; Raifer, Hartmann; Prinsloo, Earl; Przyborski, Jude M.; Hoppe, Heinrich; Shonhai, Addmore

    2015-01-01

    Heat shock proteins (Hsps) play an important role in the development and pathogenicity of malaria parasites. One of the most prominent functions of Hsps is to facilitate the folding of other proteins. Hsps are thought to play a crucial role when malaria parasites invade their host cells and during their subsequent development in hepatocytes and red blood cells. It is thought that Hsps maintain proteostasis under the unfavourable conditions that malaria parasites encounter in the host environment. Although heat shock protein 70 (Hsp70) is capable of independent folding of some proteins, its functional cooperation with heat shock protein 90 (Hsp90) facilitates folding of some proteins such as kinases and steroid hormone receptors into their fully functional forms. The cooperation of Hsp70 and Hsp90 occurs through an adaptor protein called Hsp70-Hsp90 organising protein (Hop). We previously characterised the Hop protein from Plasmodium falciparum (PfHop). We observed that the protein co-localised with the cytosol-localised chaperones, PfHsp70-1 and PfHsp90 at the blood stages of the malaria parasite. In the current study, we demonstrated that PfHop is a stress-inducible protein. We further explored the direct interaction between PfHop and PfHsp70-1 using far Western and surface plasmon resonance (SPR) analyses. The interaction of the two proteins was further validated by co-immunoprecipitation studies. We observed that PfHop and PfHsp70-1 associate in the absence and presence of either ATP or ADP. However, ADP appears to promote the association of the two proteins better than ATP. In addition, we investigated the specific interaction between PfHop TPR subdomains and PfHsp70-1/ PfHsp90, using a split-GFP approach. This method allowed us to observe that TPR1 and TPR2B subdomains of PfHop bind preferentially to the C-terminus of PfHsp70-1 compared to PfHsp90. Conversely, the TPR2A motif preferentially interacted with the C-terminus of PfHsp90. Finally, we observed that

  16. Spin transport in disordered two-dimensional hopping systems with Rashba spin-orbit interaction

    NASA Astrophysics Data System (ADS)

    Beckmann, U.; Damker, T.; Böttger, H.

    2005-05-01

    The influence of Rashba spin-orbit interaction on the spin dynamics of a topologically disordered hopping system is studied in this paper. This is a significant generalization of a previous investigation, where an ordered (polaronic) hopping system has been considered instead. It is found that in the limit where the Rashba length is large compared to the typical hopping length, the spin dynamics of a disordered system can still be described by the expressions derived for an ordered system, under the provision that one takes into account the frequency dependence of the diffusion constant and the mobility (which are determined by charge transport and are independent of spin). With these results we are able to make explicit the influence of disorder on spin related quantities as, e.g., the spin lifetime in hopping systems.

  17. Negative magnetoresistance in the variable-range-hopping regime in n-type CdSe

    NASA Astrophysics Data System (ADS)

    Zhang, Youzhu; Sarachik, M. P.

    1991-03-01

    The magnetoresistance in the variable-range-hopping regime of compensated, n-type CdSe measured between 1.6 and 6 K in the Ohmic regime at small magnetic fields is negative and obeys the expression ΔR/R=f(T)B2, with f(T)~T-α and α=1.32+/-0.04. As in recent experiments by Tremblay et al. on GaAs, this temperature dependence is observed for all samples independently of whether the resistivity at zero field indicates Mott hopping or variable-range hopping in the presence of a Coulomb gap. This implies either that the relevant dephasing time is not the hopping time, or that our current understanding of the negative magnetoresistance in these materials is incomplete.

  18. Cryopreservation and maintenance of hop material in the USDA germplasm collection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The US Department of Agriculture, Agricultural Research Service, National Clonal Germplasm Repository (NCGR) has the responsibility for conservation of the hop (Humulus L.) genetic resources. The collection includes about 530 accessions representing 7 taxa (species and subspecies) from 21 countries....

  19. Memory effects, two color percolation, and the temperature dependence of Mott variable-range hopping

    NASA Astrophysics Data System (ADS)

    Agam, Oded; Aleiner, Igor L.

    2014-06-01

    There are three basic processes that determine hopping transport: (a) hopping between normally empty sites (i.e., having exponentially small occupation numbers at equilibrium), (b) hopping between normally occupied sites, and (c) transitions between normally occupied and unoccupied sites. In conventional theories all these processes are considered Markovian and the correlations of occupation numbers of different sites are believed to be small (i.e., not exponential in temperature). We show that, contrary to this belief, memory effects suppress the processes of type (c) and manifest themselves in a subleading exponential temperature dependence of the variable-range hopping conductivity. This temperature dependence originates from the property that sites of type (a) and (b) form two independent resistor networks that are weakly coupled to each other by processes of type (c). This leads to a two-color percolation problem which we solve in the critical region.

  20. Oestrogenicity of prenylflavonoids from hops: activation of pro-oestrogens by intestinal bacteria.

    PubMed

    Possemiers, Sam; Verstraete, Willy

    2009-04-01

    For many centuries, hops (Humulus lupulus L.) have been used as essential ingredient in beers, providing the typical bitterness and hoppy flavour. However, the last few years the plant has gained increasing attention as a source of prenylflavonoids and in 1999, 8-prenylnaringenin (8-PN) was identified as the most potent phyto-oestrogen known so far. Hop extracts are therefore now marketed to reduce menopausal complaints. However, 8-PN concentrations in hops are very low, and variable efficiency of these extracts was observed. Yet, hops also contain isoxanthohumol (IX) in much higher amounts (IX/8-PN ratio in hop extracts is typically 10-20). This article reviews our recent findings on how the human intestinal microbiota may activate IX. Depending on inter-individual differences in the intestinal transformation potential, this conversion could easily increase the 8-PN exposure 10-fold. The variability in efficacy of hop extracts may therefore be explained by variable intestinal metabolism. Based on this scientific knowledge, an innovative strategy was developed to decrease this variability. First, Eubacterium limosum, capable of rapidly metabolizing all IX into 8-PN, was isolated from the complex intestinal ecosystem. This bacterium was then used to develop a new generation of hop products with increased reliability in effect. This strategy involves the use of the bacterium as probiotic, in which the bacterium is administered in combination with the original hop extract. This leads to efficient intestinal 8-PN production, also in individuals who originally did not harbour the appropriate bacteria. The findings presented in this review can therefore be considered as a typical example that good insight in the specific metabolic potential of complex microbial communities and individual bacterial species may offer important opportunities for the management and modulation of the microbial organization towards a certain metabolic function. PMID:23765740