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Sample records for atta sexdens rubropilosa

  1. POPULATION GENETICS OF Atta sexdens rubropilosa (HYMENOPTERA: FORMICIDAE

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    LIRIANA BELIZÁRIO CANTAGALLI

    2013-01-01

    Full Text Available La variabilidad genética de las hormigas Atta sexdens rubropilosa colectadas en cinco lugares distintos de Brasil fueron evaluados por la técnica PCR-RAPD. Un total de 15 primers produjeron 148 fragmentos, de los cuales 123 fueron polimórficos, lo que corresponden al 83,11 %. La estimación de la diversidad genética por el índice de Shannon fue 0,3836 y el desviación estándar fue de ± 0,2335. Estos valores demuestran una alta diversidad genética. El valor de GST fue 0,2372 y ΦPT = 0,184 lo que indica que las poblaciones están moderadamente diferenciadas y que el 82 % de la variación obtenida se produce dentro de las poblaciones. Aunque la prueba de Mantel ha demostrado una correlación entre la distancia genética y geográfica se observó que Ivatuba e Itambé (33,8 km tiene una pequeña distancia geográfica y la mayor distancia genética. La distancia inferior genética fue estimada para Maringá e Ivatuba pero estas localidades cuentan con una distancia geográfica pequeña (42,3 km, lo que indica que no hay barreras para el apareamiento entre los reproductores en estas poblaciones. El alto valor de polimorfismo (83,11 % y la capacidad de emparejamiento entre las poblaciones presentes en las regiones estu- diadas, indican que esta especie de hormiga cortadora está bien adaptada a la región, y deben ser desarrollados programas integrados de control si se convierten en plagas.

  2. Genética de poplaciones de Atta sexdens rubropilosa (Hymenoptera: Formicidae POPULATION GENETICS OF Atta sexdens rubropilosa (HYMENOPTERA: FORMICIDAE

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    LIRIANA BELIZÁRIO CANTAGALLI

    2013-04-01

    Full Text Available La variabilidad genética de las hormigas Atta sexdens rubropilosa colectadas en cinco lugares distintos de Brasil fueron evaluados por la técnica PCR-RAPD. Un total de 15 primers produjeron 148 fragmentos, de los cuales 123 fueron polimórficos, lo que corresponden al 83,11 %. La estimación de la diversidad genética por el índice de Shannon fue 0,3836 y el desviación estándar fue de ± 0,2335. Estos valores demuestran una alta diversidad genética. El valor de G ST fue 0,2372 y ΦPT = 0,184 lo que indica que las poblaciones están moderadamente diferenciadas y que el 82 % de la variación obtenida se produce dentro de las poblaciones. Aunque la prueba de Mantel ha demostrado una correlación entre la distancia genética y geográfica se observó que Ivatuba e Itambé (33,8 km tiene una pequeña distancia geográfica y la mayor distancia genética. La distancia inferior genética fue estimada para Maringá e Ivatuba pero estas localidades cuentan con una distancia geográfica pequeña (42,3 km, lo que indica que no hay barreras para el apareamiento entre los reproductores en estas poblaciones. El alto valor de polimorfismo (83,11 % y la capacidad de emparejamiento entre las poblaciones presentes en las regiones estudiadas, indican que esta especie de hormiga cortadora está bien adaptada a la región, y deben ser desarrollados programas integrados de control si se convierten en plagas.The genetic variability of Atta sexdens rubropilosa leaf-cutting ants collected from five brazilian localities was evaluated with PCR-RAPD technique. We used 15 primers producing 148 fragments of which 123 (83.11 % contained polymorphisms. The estimated Shannon index was 0.3836 ± 0.2335 showing that these ants possess high genetic diversity. The G ST value was 0.2372 and ΦPT = 0.184, indicating that the analyzed populations are moderately differentiated and 82 % of the variation obtained occur within populations. Although Mantel's test had shown correlation

  3. Electrophysiological responses of Atta sexdens rubropilosa workers to essential oils of eucalyptus and its chemical composition.

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    Batista-Pereira, Luciane G; Fernandes, João B; da Silva, M Fátima G E; Vieira, Paulo C; Bueno, Odair C; Corrêa, Arlene G

    2006-01-01

    The leaf-cutting ant Atta sexdens rubropilosa Forel, 1908 is the most harmful of the Eucalyptus pests, causing severe losses in wood production through defoliation. Various strategies have been tried and effort spent on the development of methods to control this pest, however no practical and environmentally acceptable one currently exists. In this work the chemical composition of the essential oil of seven Eucalyptus species was identified and the selectivity and sensitivity of antennal receptors of A. sexdens rubropilosa workers to the volatile compounds were determined using the electroantennographic technique (EAG and GC-EAD). Analysis by GC-EAD showed in E. cloesiana and E. maculata, respectively, seventeen and sixteen terpenes that elicited responses in ant workers' antennae, indicating the potential role of the essential oils as allelochemicals that determine the choice of the foraging material.

  4. Variability of non-mutualistic filamentous fungi associated with Atta sexdens rubropilosa nests.

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    Rodrigues, A; Pagnocca, F C; Bacci, M Júnior; Hebling, M J A; Bueno, O C; Pfenning, L H

    2005-01-01

    A survey of the filamentous fungi other than the symbiotic one found in association with Atta sexdens rubropilosa colonies was carried out. Different fungal species (27 taxa) were isolated a few days after treating the workers with toxic baits (sulfluramid; Mirex-S), from 40 laboratory and 20 field nests. Syncephalastrum racemosum (54%) and Escovopsis weberi (21%), Trichoderma harzianum (38%) and Fusarium oxysporum (23%) were the prevalent species in laboratory and field nests, respectively. Acremonium kiliense, Acremonium strictum, E. weberi, F. oxysporum, Fusarium solani, Moniliella suaveolens and T. harzianum were found in both nests' groups. We revealed that many filamentous fungi can co-exist in a dormant state inside the nests of these insects and some of them appear to be tightly associated with this environment.

  5. Ricinus communis and Jatropha curcas (Euphorbiaceae) seed oil toxicity against Atta sexdens rubropilosa (Hymenoptera: Formicidae).

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    Alonso, E C; Santos, D Y A C

    2013-04-01

    Leaf-cutting ants are the main herbivores in the New World tropics. Although the toxicity of seed oils against these ants has been poorly investigated, previous results revealed that seed oils exert considerable toxic activity against these insects. This paper analyzes the toxic action and deterrent properties of castor oil, Ricinus communis L., and physic nut oil, Jatropha curcas L., against workers of the leaf-cutting ant Atta sexdens rubropilosa reared in laboratory. Toxic effect was analyzed by feeding insects artificial diets supplemented with different oil concentrations and direct contact with the two oils. Deterrent activity was assessed by measuring the frequency of attendance to diets during the first 48 h of the ingestion bioassay. Castor oil at 10 and 30 mg/ml and physic nut oil at 5, 10, and 30 mg/ml were toxic by ingestion. In the direct contact bioassay, toxicity was observed for physic nut oil at 0.1 and 0.2 mg/ml, whereas castor oil exerted toxic effects only when the highest concentration was applied. Also, castor oil had a more pronounced deterrent effect against the leaf-cutting ant, compared with physic nut oil. Methods to apply these oils to control these insects are discussed.

  6. Isolation of compounds attractive to the leaf-cutting ant Atta sexdens rubropilosa forel (hymenoptera: Formicidae from Mabea fistulifera elaiosome

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    Ethel Fernandes de O. Peternelli

    2008-01-01

    Full Text Available Mabea fistulifera (Euphorbiaceaeis a pioneer plant species with seeds dispersed by the ant Atta sexdens rubropilosa. Since the ants are attracted to the seeds to use its elaiosome as a source of energy, we investigated its composition. The elaiosomes from 13,000 seeds were extracted with a methanol:chloroform mixture (2:1 v/v and yielded 22% of a residue. This residue was fractionated by column chromatography and its composition determined by infrared spectroscopy and chromatography/mass spectrometry (GC-MS. The elaiosome lipids are constituted mainly by free fatty acids, triacylglycerols and minor quantities of monoacylglycerols or diacylglycerols.

  7. Influence of physical and chemical factors during foraging and culture of the symbiont fungus in Atta sexdens rubropilosa (Hymenoptera: Formicidae)

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    SANDRA S. VERZA; LUIZ C. FORTI; JULIANE F. S. LOPES; ROBERTO S.CAMARGO; CARLOS A. O. MATOS

    2007-01-01

    The aim of this paper is to investigate the influence of physical and chemical factors on transport and use of substrate for Atta sexdens rubropilosa workers. Three types of rectangular fragments were used to study the physical influence factors: filter paper with paraffin, filter paper without paraffin and polyester film. To study the chemical factors, some fragments were impregnated with organic extract of orange albedo, others were soaked with soybean oil and for the remaining ones nothing was applied. The following parameters were evaluated: (i) attractiveness of substrate for transport and number of loading workers per treatment; (ii) foraged material incorporation; (iii) rejection by numbers of fragments deposited in the garbage or beside the fungus garden. All the polyester film fragments carried out to the fungus garden were subsequently rejected. We verified that chemical factors of the substrate were more quickly detected by the workers, whereas physical factors were used as a criterion in the decision-making to reject or accept the substrate collected:

  8. Activity of Ricinus communis (Euphorbiaceae) and ricinine against the leaf-cutting ant Atta sexdens rubropilosa (Hymenoptera: Formicidae) and the symbiotic fungus Leucoagaricus gongylophorus.

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    Bigi, Maria Fátima; Torkomian, Vera L V; de Groote, Suzanne T C S; Hebling, Maria José A; Bueno, Odair C; Pagnocca, Fernando C; Fernandes, João B; Vieira, Paulo C; da Silva, Maria Fátima G F

    2004-09-01

    The focus of this study was the identification of compounds from plant extracts for use in crop protection. This paper reports on the toxic activity of fractions of leaf extracts of Ricinus communis L (Euphorbiaceae) and isolated active compounds in the leaf-cutting ant Atta sexdens rubropilosa Forel and its symbiotic fungus Leucoagaricus gongylophorus (Singer) Möller. The main compounds responsible for activity against the fungus and ant in leaf extracts of R communis were found to be fatty acids for the former and ricinine for the ants.

  9. CUSTO COMPARATIVO DE CONTROLE À FORMIGA CORTADEIRA Atta sexdens rubropilosa Forel 1908, EMPREGANDO-SE ISCAS GRANULADAS COMERCIAIS E UMA ISCA EXPERIMENTAL COMPARATIVE COST CONTROL OF Atta sexdens rubropilosa FOREL 1908 USING COMMERCIAL GRAIN BAITS AND AN EXPERIMENTAL BAIT

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    Antônio Lopes da Silva

    2007-09-01

    Full Text Available

    Realizou-se um experimento de controle à formiga cortadeira Atta sexdens rubropilosa FOREL 1908, nos campos da Universidade Federal de Goiás (dezembro de 1972, com a finalidade de comparar o custo de controle por sauveiro, utilizando-se uma isca granulada experimental “EAV-041-A” idealizada pelo autor, com outras iscas existentes no mercado. Foram realizados 4 tratamentos (Mirex, Isca Shell, EAV-041-A e Agroceres na base de 10 g de cada isca por m² de sauveiro, em 5 repetições, constando cada parcela de 3 formigueiros, perfazendo um total de 60. O delineamento foi inteiramente ao acaso. Para a análise econômica dos resultados, foram utilizados os fatores: custo da isca, sua eficiência percentual e o valor da mão-de-obra requerida, para se determinar o custo médio de controle de um sauveiro extinto. Pelos valores calculados, como resultado, obteve-se o custo médio por sauveiro extinto na seguinte ordem: com a isca “EAV-04l-A” custou Cr$ 2,27; com a “Isca Shell” Cr$ 3,41; com “Agroceres” Cr$ 4,29 e com “Mirex” Cr$ 5,44, evidenciando a economia em favor da "EAV-041-A", tendo em vista o seu menor custo por quilograma (Na época em que os cálculos foram realizados, o valor cambial do Dólar era de Cr$ 6,00.

    An Experiment was conducted using a clorimated experimental bait called EAV-041-A. This experiment was conducted to determine the efficiency of EAV-041-A using the leaf-cutting ant Atta sexdens rubropilosa as the test. The experiment was executed in Goiânia, Goiás, comparing it with the commercial baits: Mirex, Isca Shell and Agroceres AG-005. Results obtained showed Mirex was superior giving 93.30% control of the nests, EAV-041-A 80.00% and Isca Shell and Agroceres both qave 73.30% control. Total cost of application was calculated based on price of the bait on

  10. Seleção de isolados de Metarhizium anisopliae e Beauveria bassiana patogênicos a soldados de Atta bisphaerica e Atta sexdens rubropilosa em condições de laboratório Selection of Metarhizium anisopliae and Beauveria bassiana isolates pathogenic to Atta bisphaerica and Atta sexdens rubropilosa soldiers under laboratory conditions

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    Alzimiro Marcelo Conteiro Castilho

    2010-06-01

    Full Text Available As formigas do gênero Atta são pragas importantes de diversas culturas agrícolas, pastagens e reflorestamentos. Os fungos entomopatogênicos estão entre os fatores naturais de mortalidade dessas formigas e por isso apresentam potencial para serem usados no controle biológico dessa praga. O presente trabalho teve como objetivo selecionar isolados de Metarhizium anisopliae e Beauveria bassiana patogênicos a soldados de Atta bisphaerica e Atta sexdens rubropilosa em condições de laboratório. Para a avaliação da patogenicidade, foram utilizados oito isolados de M. anisopliae e seis de B. bassiana. O experimento foi conduzido em DIC, sendo a parcela composta por um grupo de 10 soldados por espécie de formiga, sendo utilizadas três repetições por tratamento. Para cada isolado, três grupos de soldados foram pulverizados com suspensão de 1,0 x 10(8 conídios ml-1 e mantidos em câmara úmida (25±1°C, 80±1% de UR e no escuro sem alimentação, sendo a mortalidade verificada diariamente. Dos 14 isolados testados, quatro de M. anisopliae e quatro de B. bassiana foram patogênicos aos soldados de ambas as espécies de formigas. A virulência foi avaliada para os isolados que causaram mortalidade igual ou maior a 50%. Para cada isolado, suspensões contendo 1,0 x 10(6 a 1,0 x 10(11 conídios ml-1 foram pulverizadas sobre três grupos de 10 soldados e igualmente acondicionados como no teste de patogenicidade. A porcentagem de mortalidade foi calculada a cada 24 horas para determinação do TL50. O isolado ENA04 de M. anisopliae foi mais patogênico, causando mais de 80% de mortalidade nos primeiros três dias após a inoculação, apresentou maior capacidade de esporular nos cadáveres dos soldados e foi o mais virulento para os soldados de A. bisphaerica, com um TL50 de 1,15 dias. Todos os isolados patogênicos aos soldados de A. sexdens rubropilosa foram igualmente virulentos.The ants of the genus Atta are important pests of several

  11. Determinação do fator de conversão em colônias de Atta sexdens rubropilosa (Hymenoptera: Formicidae e sua relação com a qualidade do material vegetal cortado Determination of the conversion factor in colonies of Atta sexdens rubropilosa (Hymenoptera: Formicidae and its relationship with the quality of harvested leaf substrate

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    Leandro Sousa-Sou

    2007-02-01

    Full Text Available As formigas cortadeiras (Atta e Acromyrmex são consideradas importantes pragas na agricultura e silvicultura, mas pouco se sabe sobre os reais danos dessas espécies. Uma forma bastante difundida de avaliação do dano é por meio do cálculo da taxa de conversão, dividindo-se o peso do material cortado pelo peso de lixo produzido pelas colônias. Foi levantada a hipótese de que a qualidade do substrato cortado pode influenciar no forrageamento das operárias, alterando a taxa de conversão e dificultando as estimativas de dano. A taxa de conversão de oito colônias de Atta sexdens rubropilosa Forel (Hymenoptera: Formicidae foi calculada com duas espécies vegetais com diferentes concentrações de lignina e celulose, para testar essa hipótese. Colônias mantidas com folhas de baixa qualidade (razão lignina/celulose elevada tiveram maior forrageamento e produziram mais lixo. Entretanto, a taxa de conversão das colônias foi semelhante com essas duas plantas (média = 1,54. Esse valor está dentro da variação encontrada para outras espécies no campo (1,5-1,8, indicando um fator semelhante de conversão entre os gêneros Atta e Acromyrmex. O consumo médio de material vegetal, em termos de pesos seco e fresco, de uma colônia de A. sexdens rubropilosa com 4.500 operárias, foi estimado em 520 e 1.100 g/ano, respectivamente.Leaf-cutting ants (Atta and Acromyrmex are important pests in agriculture and forestry, although few data exist on the actual damage caused by these species. A model used to evaluate damage by leaf-cutting ants are estimates of the conversion factor, which is the ratio between the weight of material cut by the ants and the refuse produced by the colonies. The hypothesis that substrate quality influences foraging by workers, modifying the conversion factor and impairing damage estimates was put forward. To test this hypothesis, the conversion factor was calculated for eight colonies of Atta sexdens rubropilosa Forel

  12. Preferência de saúva limão, Atta sexdens rubropilosa Forel, 1908 (Hymenoptera, formicidae a diferentes espécies florestais, em condições de laboratório.

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    Otávio Peres Filho

    2010-08-01

    Full Text Available Avaliou-se a preferência de saúva limão, Atta sexdens rubropilosa Forel, 1908, para 41 espécies florestais nativas e exóticas, em condições de laboratório. As espécies mais transportadas foram gmelina (Gmelina arborea, leucena (Leucaena leucocephala, pau-ferro (Caesalpinia ferrea, albizia (Albizia lebbeck e orelha-de-negro (Enterolobium contortisiliquum e as menos transportadas foram eucalipto (Eucalyptus grandis, jequitibá (Cariniana strellensis e mutamba (Guazuma tomentosa.

  13. Ocorrência de fungos filamentosos em ninhos de Atta sexdens rubropilosa Forel, 1908 (Hymenoptera: Formicidae) submetidos a tratamentos com iscas tóxicas

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    Rodrigues,André

    2004-01-01

    Além do fungo simbionte que as formigas cortadeiras cultivam para alimentação, outros microrganismos podem ser encontrados em seus ninhos. Apesar das informações disponíveis recentemente na literatura, ainda pouco se sabe sobre esta microbiota, suas inter-relações e em quais circunstâncias podem interferir na simbiose. Este trabalho teve a intenção de fazer um levantamento das principais espécies de fungos filamentosos que podem ocorrer nos ninhos de Alta sexdens rubropilosa (saúva). Para fac...

  14. Survival of Atta sexdens workers on different food sources.

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    Silva, Aline; Bacci, Maurício; Gomes de Siqueira, Célia; Correa Bueno, Odair; Pagnocca, Fernando Carlos; Aparecida Hebling, Maria José

    2003-04-01

    Leaf-cutting ants belonging to the tribe Attini are major herbivores and important agriculture pests in the neotropics, these ants being thought to feed on the sap which exudes from the plant material which they cut and also on the mycelium of a symbiotic fungus that grows on plant material inside their nests in what is called "the fungus garden". However, we have found that the survival of Atta sexdens worker ants on leaves, on mycelium of the ants' symbiotic fungus, Leucoagaricus gongylophorus, or on plant polysaccharides was the same as that of starved A. sexdens, while, conversely, significantly longer survival was achieved by ants fed on the fungus garden material or on some of the products (especially glucose) of the hydrolysis of plant polysaccharides. We found that the fungus garden contained glucose at a higher concentration than that found in leaves or fungal mycelium, and that this glucose was consumed by the ant to the extent that it was probably responsible for up to 50% of the nutritional needs of the workers. The fungus garden contained polysaccharide degrading enzymes (pectinase, amylase, xylanase and cellulase) in proportions similar to that observed in laboratory cultures of L. gongylophorus. It thus appears that A. sexdens workers obtain a significant part of their nutrients from plant polysaccharide hydrolysis products produced by the action of extracellular enzymes released by L. gongylophorus. In this paper we discuss the symbiotic nutrition strategy of A. sexdens workers and brood and the role played by plant polysaccharides in the nutrition of attine ants.

  15. Fungos Filamentosos Associados às Espécies Atta sexdens (Linnaeus e Atta laevigata (F. Smith (Hymenoptera: Formicidae

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    Aline Dornelas

    2016-04-01

    Abstract. Leaf-cutting ants, Atta and Acromyrmex genera, are considered major pests in a neotropical agroforestry system because they cut plant material that will serve as food for the symbiotic fungus cultivated by them. Several fungi naturally occurring in the soil can be found associated with leaf-cutting ants, many of them are demonstrably entomopathogenic. However, these agents have not been used as biological control of leaf-cutting ants. The aim of this study was to isolate and to identify filamentous fungi associated with forage workers of Atta sexdens (Linnaeus and Atta laevigata (F. Smith and to test their pathogenicity against workers from laboratory colonies. To isolate filamentous fungi, it was collected a total of 180 forage workers (30 in each colony in six field colonies, 90 of A. sexdens and 90 workers of A. laevigata. Six fungi species from A. sexdens were isolated and identified: Metarhizium anisopliae (Metchnikoff Sorokin, Aspergillus flavus Link, Acremonium sp. 1, Aspergillus sp. 1, Colletotrichum sp. and Acremonium sp. 2. In A. laevigata, it was found four species: Mucor sp., Aspergillus flavus, Fusarium solani (Martius Saccardo, Aspergillus niger van Tieghem. Three of these fungi were selected for pathogenicity tests against workers of the leaf-cutting ant A. sexdens: A. flavus, A. niger and M. anisopliae. The LT50 (time to cause 50% mortality of workers in tests with A. niger and M. anisopliae were five days and significantly lower than the control group. Therefore, further tests should proceed with those isolates to demonstrate their potential use in the biological control of leaf-cutting ants.

  16. On the morphology of the worker immatures of the leafcutter ant Atta sexdens Linnaeus (Hymenoptera: Formicidae).

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    Solis, Daniel Russ; Fox, Eduardo Gonçalves Paterson; Ceccato, Marcela; Reiss, Itamar Cristina; Décio, Pâmela; Lorenzon, Natalia; Da Silva, Natiele Gonçalves; Bueno, Odair Correa

    2012-08-01

    Leafcutter ants of the genus Atta Fabricius are serious agricultural pests. Morphological studies of immature stages within this group are few, and the data provided for species of considerable importance are usually incomplete. In this study, the immatures of Atta sexdens Linnaeus are described and compared using light and scanning electron microscopy. Only specimens from founding stage colonies (i.e., lacking adult workers) were used. The existence of four larval instars was estimated by a frequency plot of maximum head widths, and the larvae of different instars differed from each other mainly by their bodily dimensions. Worker larvae belonged to two distinct morphological castes: (1) gardeners and nurses and (2) within-nest generalists. The worker larvae described in this study differed from a previous description of the same species by the following traits: the existence of a genal lobe, the number of clypeal hairs, the presence of two hairs on the ninth abdominal somite, the presence of hairs on the anterior surface of the labrum, and the shape of the maxillary palpus. This study provides a comparative analysis of immature stages of A. sexdens that may be relevant to future morphological and biological studies of the Attini.

  17. Queen influence on workers behavior of the leaf-cutting ant Atta sexdens rubropilosa (Forel, 1908

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    L. Sousa-Souto

    Full Text Available In an ant colony, the queen is the single reproducer and can interact with her workers via pheromones and cuticular compounds. However, in most species queen importance is not restricted to reproduction: in the initial development of the colony, her presence might play a more important role. In this work, we studied the effects of queen absence on workers behavior displayed in the foraging arena. Ant’s mortality and refuse accumulation was also measured daily. The results showed that queen absence did not alter either workers behavior or foraging efficiency. However, we observed increased ant mortality accompanied by a decrease in refuse dumping outside the nest. These results corroborate the hypothesis that environmental factors are more important than intrinsical factors in the allocation of external tasks. Probably, the queen could only influence internal activities of the colony.

  18. Production of polysaccharidases in different carbon sources by Leucoagaricus gongylophorus Möller (Singer), the symbiotic fungus of the leaf-cutting ant Atta sexdens Linnaeus.

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    Silva, Aline; Bacci, Maurício; Pagnocca, Fernando C; Bueno, Odair C; Hebling, Maria J A

    2006-07-01

    Leucoagaricus gongylophorus, the fungus cultured by the leaf-cutting ant Atta sexdens, produces polysaccharidases that degrade leaf components by generating nutrients believed to be essential for ant nutrition. We evaluated pectinase, amylase, xylanase, and cellulase production by L. gongylophorus in laboratory cultures and found that polysaccharidases are produced during fungal growth on pectin, starch, cellulose, xylan, or glucose but not cellulase, whose production is inhibited during fungal growth on xylan. Pectin was the carbon source that best stimulated the production of enzymes, which showed that pectinase had the highest production activity of all of the carbon sources tested, indicating that the presence of pectin and the production of pectinase are key features for symbiotic nutrition on plant material. During growth on starch and cellulose, polysaccharidase production level was intermediate, although during growth on xylan and glucose, enzyme production was very low. We propose a possible profile of polysaccharide degradation inside the nest, where the fungus is cultured on the foliar substrate.

  19. Dealing with water deficit in Atta ant colonies: large ants scout for water while small ants transport it

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    Antonio Carlos Da-Silva

    2012-07-01

    Leafcutter ants (Atta sexdens rubropilosa (Forel 1908 have an elaborate social organization, complete with caste divisions. Activities carried out by specialist groups contribute to the overall success and survival of the colony when it is confronted with environmental challenges such as dehydration. Ants detect variations in humidity inside the nest and react by activating several types of behavior that enhance water uptake and decrease water loss, but it is not clear whether or not a single caste collects water regardless of the cost of bringing this resource back to the colony. Accordingly, we investigated water collection activities in three colonies of Atta sexdens rubropilosa experimentally exposed to water stress. Specifically, we analyzed whether or not the same ant caste foraged for water, regardless of the absolute energetic cost (distance of transporting this resource back to the colony. Our experimental design offered water sources at 0 m, 1 m and 10 m from the nest. We studied the body size of ants near the water sources from the initial offer of water (time  =  0 to 120 min, and tested for specialization. We observed a reduction in the average size and variance of ants that corroborated the specialization hypothesis. Although the temporal course of specialization changed with distance, the final outcome was similar among distances. Thus, we conclude that, for this species, a specialist (our use of the word “specialist” does not mean exclusive task force is responsible for collecting water, regardless of the cost of transporting water back to the colony.

  20. Limonoids from andiroba oil and Cedrela fissilis and their insecticidal activity

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    Ambrozin, Alessandra R.P.; Leite, Ana C.; Vieira, Paulo C.; Fernandes, Joao B.; Silva, M. Fatima das G. Fernandes da [Sao Carlos Univ., SP (Brazil). Dept. de Quimica]. E-mail: paulo@dq.ufscar.br; Bueno, Fabiana C.; Bueno, Odair C.; Pagnocca, Fernando C.; Hebling, Jose A.; Bacci Junior, Mauricio [UNESP, Rio Claro, SP (Brazil). Centro de Estudos de Insetos Sociais

    2006-05-15

    Nine limonoids were isolated from Carapa guianensis and Cedrela fissilis. Among them, 1,2-dihydro-3{beta}-hydroxy-7-deacetoxy-7-oxogedunin is a new compound. Moreover, the assignments of some chemical shifts of xyloccensin k have been corrected and {sup 1}H NMR data of 7-deacetylgedunin have been assigned for the first time. These isolated limonoids were assayed on Atta sexdens rubropilosa workers showing moderate insecticidal activities. (author)

  1. Limonoids from Cipadessa fruticosa and Cedrela fissilis and their insecticidal activity

    Energy Technology Data Exchange (ETDEWEB)

    Leite, Ana C.; Fernandes, Joao B.; Vieira, Paulo C.; Silva, M. Fatima das G. Fernandes da [Sao Carlos Univ., SP (Brazil). Dept. de Quimica]. E-mail: djbf@power.ufscar.br; Bueno, Fabiana C.; Oliveira, Cintia G.; Bueno, Odair C.; Pagnocca, Fernando C.; Hebling, M. Jose A.; Bacci Junior, Mauricio [UNESP, Rio Claro, SP (Brazil). Centro de Estudos de Insetos Sociais

    2005-11-15

    The chemical investigation of the fruits of Cipadessa fruticosa (Meliaceae) afforded the new limonoid cipadesin B and the known swietemahonolide. From the roots of Cedrela fissilis (Meliaceae) were isolated the limonoid 3{beta}-acetoxycarapin, new as natural product, along with thiterpenes oleanolic and oleanonic acid. These compounds and other six mexicanolide limonoids previously isolated from C. fruticosa showed insecticidal activity against the leaf-cutting ants Atta sexdens rubropilosa. (author)

  2. Square Van Atta reflector with conducting mounting flame

    DEFF Research Database (Denmark)

    Nielsen, Erik Dragø

    1970-01-01

    A theoretical and numerical analysis of square Van Atta reflectors has been carried out with or without a conducting plate, used for mounting of the antenna elements. The Van Atta reflector investigated has antenna elements which are parallel half-wave dipoles interconnected in pairs by transmiss......A theoretical and numerical analysis of square Van Atta reflectors has been carried out with or without a conducting plate, used for mounting of the antenna elements. The Van Atta reflector investigated has antenna elements which are parallel half-wave dipoles interconnected in pairs...

  3. Professor Atta invited to attend WSIS as `eminent scientist'

    CERN Multimedia

    2003-01-01

    Ministry of Science and Technology Prof. Atta-ur-Rahman has been nominated as an "eminent scientist" to attend the roundtables during "World Summit on the Information Society (WSIS)" on December 12 (1 paragraph).

  4. High-speed counter-current chromatographic isolation of ricinine, an insecticide from Ricinus communis.

    Science.gov (United States)

    Cazal, Cristiane de Melo; Batalhão, Jaqueline Raquel; Domingues, Vanessa de Cássia; Bueno, Odair Corrêa; Filho, Edson Rodrigues; Forim, Moacir R; da Silva, Maria Fátima G Fernandes; Vieira, Paulo Cezar; Fernandes, João Batista

    2009-05-08

    The alkaloid ricinine, an insecticide for leaf-cutting ant (Atta sexdens rubropilosa), was obtained from Ricinus communis. A two-phase solvent system composed of CH(2)Cl(2)/EtOH/H(2)O (93:35:72, v/v/v) was used for high-speed counter-current chromatographic (HSCCC) isolation of ricinine in high yield and with over 96% purity, as determined by liquid and gas chromatography-mass spectrometry (LC-MS and GC-MS). Identification of ricinine was performed by comparison of (1)H NMR, (13)C NMR and LC-MS/MS data.

  5. Isolation of xanthyletin, an inhibitor of ants' symbiotic fungus, by high-speed counter-current chromatography.

    Science.gov (United States)

    Cazal, Cristiane de Melo; Domingues, Vanessa de Cássia; Batalhão, Jaqueline Raquel; Bueno, Odair Corrêa; Filho, Edson Rodrigues; da Silva, Maria Fátima G Fernandes; Vieira, Paulo Cezar; Fernandes, João Batista

    2009-05-08

    Xanthyletin, an inhibitor of symbiotic fungus (Leucoagaricus gongylophorus) of leaf-cutting ant (Atta sexdens rubropilosa), as well as suberosin, seselin and xanthoxyletin were isolated from Citrus sinensis grafted on Citrus limonia. A two-phase solvent system composed of hexane/ethanol/acetonitrile/water (10:8:1:1, v/v) was used for the high-speed counter-current chromatographic isolation of xanthyletin with high yield and over 99% purity as determined by liquid and gas chromatography with mass spectrometry detection. Identifications were performed by UV spectra, IR spectra, (1)H NMR and (13)C NMR.

  6. Activities of extracts and compounds from Spiranthera odoratissima St. Hil. (Rutaceae) in leaf-cutting ants and their symbiotic fungus

    Energy Technology Data Exchange (ETDEWEB)

    Terezan, Ana Paula; Fernandes, Joao B.; Silva, M. Fatima das Gracas Fernandes da; Vieira, Paulo C. [Universidade Federal de Sao Carlos (UFSCAR), Sao Carlos, SP (Brazil). Dept. de Quimica; Rossi, Raquel Andrade; Almeida, Roberta N.A.; Freitas, Tais Garcia; Bueno, Odair C.; Pagnocca, Fernando C. [Universidade Estadual Paulista (UNESP), Rio Claro, SP (Brazil). Centro de Estudos de Insetos Sociais; Pirani, Jose R., E-mail: djbf@power.ufscar.b [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Biociencias. Dept. de Botanica

    2010-07-01

    The study of the Spiranthera odoratissima St. Hil (Rutaceae) branches extracts led to the isolation of the furoquinoline (dictamine, gamma-fagarine and skimmianine) and 2-arylquinoli-4-one (1-methyl-2-phenylquinoline-4-one) alkaloids and limonoids (limonexic acid and limonin). The compounds 1-methyl-2-phenylquinoline-4-one and limonexic acid were isolated for the first time from the Spiranthera. These furoquinoline and 2-arylquinoli-4-one alkaloids and limonoids showed insecticidal and/or fungicidal activity in the nest of the Atta sexdens rubropilosa. (author)

  7. Are workers of Atta leafcutter ants capable of reproduction?

    DEFF Research Database (Denmark)

    Dijkstra, Michiel Bendert; Boomsma, Jacobus Jan

    2006-01-01

    . However, all males were tiny (3.5-9 mm long) compared to normal queen sons (16 mm long), and would almost certainly be unable to mate. We also found reproductive eggs, but most of these had no yolk and were thus inviable. We conclude that Atta workers are not completely infertile, but that worker...... fertility is low compared to the sister genus Acromyrmex, where workers routinely produce normally-size males after queen loss in the laboratory. We hypothesize that worker reproduction in orphaned Atta field colonies is almost never successful because the last workers die before their sons can be raised...

  8. Extrações de óleos de sementes de citros e suas atividades sobre a formiga cortadeira Atta sexdens e seu fungo simbionte

    Directory of Open Access Journals (Sweden)

    Fernandes João B.

    2002-01-01

    Full Text Available Seeds Citrus oils (C. sinensis, C. limon and C. reticulata extraction with hexane in a soxhlet apparatus and through supercritical fluid (CO2 were done. Besides triglycerides, the oils obtained with hexane comprised volatile compounds such as terpenes and fatty alcohols, esters, and aldehydes. However, the oils obtained by extraction with supercritical fluid presented only triglycerides. These results indicate that the extraction using supercritical fluid presents better selectivity. The activity of the oils on the development of the ant symbiotic fungus, Leucoagaricus gongylophorus, showed week activity and the topic insecticide assay showed better activity for the tangerine seed oil.

  9. A Van Atta reflector consisting of half-wave dipoles

    DEFF Research Database (Denmark)

    Appel-Hansen, Jørgen

    1966-01-01

    The reradiation pattern of a passive Van Atta reflector consisting of half-wave dipoles is investigated. The character of the reradiation pattern first is deduced by qualitative and physical considerations. Various types of array elements are considered and several geometrical configurations of t...

  10. Development and validation of a RP-HPLC method to determine the xanthyletin content in biodegradable polymeric nanoparticles

    Directory of Open Access Journals (Sweden)

    Cristiane de Melo Cazal

    2014-01-01

    Full Text Available Xanthyletin is used as an inhibitor of the symbiotic fungus (Leucoagaricus gongylophorus of the leaf-cutting ant (Atta sexdens rubropilosa, one of the most significant agricultural plague insects. The incorporation of this compound into nanoparticles is a promising approach to effectively control leaf-cutting ants. This study presents the development and validation of a specific analytical method using high-performance liquid chromatography (HPLC for quantification of the xanthyletin content in biodegradable polymeric nanoparticles. The analytical methodology developed was specific, linear, accurate, precise, and robust. The absolute recovery of xanthyletin in colloidal suspensions was nearly 100%. The HPLC method proved reliable for the quantification of xanthyletin content in nanoparticle formulations.

  11. Leaf-cutting ants toxicity of limonexic acid and degraded limonoids from Raulinoa echinata: X-ray structure of epoxy-fraxinellone

    Energy Technology Data Exchange (ETDEWEB)

    Biavatti, Maique W.; Westerlon, Rosangela [Universidade do Vale do Itajai, SC (Brazil). Programa de Pos-Graduacao em Ciencias Farmaceuticas]. E-mail: maique@univali.br; Vieira, Paulo C.; Silva, M. Fatima G.F. da; Fernandes, Joao B. [Sao Carlos Univ., SP (Brazil). Dept. de Quimica; Penaflor, M. Fernanda G.V.; Bueno, Odair C. [UNESP, Rio Claro, SP (Brazil). Centro de Estudos de Insetos Sociais; Ellena, Javier [Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. de Fisica

    2005-11-15

    Phytochemical survey of roots extracts of the South Brazilian endemic plant Raulinoa echinata Cowan, Rutaceae led to the isolation of known degraded limonoids: fraxinellone, fraxinellonone and epoxy-fraxinellone. The latter was previously isolated also from the stems, but the relative configuration could not be solved by NMR experiments. This paper deals with the X-ray diffraction analysis of epoxy-fraxinellone and its toxicity to leaf-cutting ants, describes the isolation of fraxinellonone and fraxinellone for the first time in Raulinoa. Epoxy-fraxinellone showed no toxicity to the leaf-cutting ants (Atta sexdens rubropilosa). The limonoid limonexic acid, isolated from stems, presented high toxicity to the leaf-cutting ants, diminishing considerably their longevity. (author)

  12. Evaluation of the Toxicity of Virola sebifera Crude Extracts, Fractions and Isolated Compounds on the Nest of Leaf-Cutting Ants

    Directory of Open Access Journals (Sweden)

    Keylla Utherdyany Bicalho

    2012-01-01

    Full Text Available The phytochemical study of Virola sebifera leaves led to the isolation of three lignans: (+-sesamin, (−-hinokinin, and (−-kusunokinin and three flavonoids: quercetin-3-O-α-L-rhamnoside, quercetin-3-O-β-D-glucoside, and quercetin-3-methoxy-7-O-β-D-glucoside by using techniques as high-speed counter-current chromatography and high-performance liquid chromatography. The crude extracts, fractions, and isolated compounds were evaluated for their insecticidal and fungicidal potential against Atta sexdens rubropilosa and its symbiotic fungus Leucoagaricus gongylophorus. The bioassay results showed a high insecticidal activity for the methanol crude extract of the leaves of V. sebifera and its n-hexane, dichloromethane and ethyl acetate fractions. The fungicidal bioassay revealed high toxicity of the lignans against L. gongylophorus.

  13. Draft Genome Sequence of the Ant-associated Fungus Phialophora attae (CBS 131958)

    NARCIS (Netherlands)

    de Hoog, S.

    2015-01-01

    The black yeast Phialophora attae was isolated from the cuticle of tropical ant gynes. The ant-fungus association is sustained due to symbiotic evolutionary adaptations that allow fungal assimilation and tolerance of toxic compounds produced by the ant. The genome sequence of the first ant-associate

  14. Association between Pseudonocardia symbionts and Atta leaf-cutting ants suggested by improved isolation methods.

    Science.gov (United States)

    Marsh, Sarah E; Poulsen, Michael; Gorosito, Norma B; Pinto-Tomás, Adrián; Masiulionis, Virginia E; Currie, Cameron R

    2013-03-01

    Fungus-growing ants associate with multiple symbiotic microbes, including Actinobacteria for production of antibiotics. The best studied of these bacteria are within the genus Pseudonocardia, which in most fungus-growing ants are conspicuously visible on the external cuticle of workers. However, given that fungus-growing ants in the genus Atta do not carry visible Actinobacteria on their cuticle, it is unclear if this genus engages in the symbiosis with Pseudonocardia. Here we explore whether improving culturing techniques can allow for successful isolation of Pseudonocardia from Atta cephalotes leaf-cutting ants. We obtained Pseudonocardia from 9 of 11 isolation method/colony component combinations from all 5 colonies intensively sampled. The most efficient technique was bead-beating workers in phosphate buffer solution, then plating the suspension on carboxymethylcellulose medium. Placing these strains in a fungus-growing ant-associated Pseudonocardia phylogeny revealed that while some strains grouped with clades of Pseudonocardia associated with other genera of fungus-growing ants, a large portion of the isolates fell into two novel phylogenetic clades previously not identified from this ant-microbe symbiosis. Our findings suggest that Pseudonocardia may be associated with Atta fungus-growing ants, potentially internalized, and that localizing the symbiont and exploring its role is necessary to shed further light on the association.

  15. Seminal fluid enhances sperm viability in the leafcutter ant Atta colombica

    DEFF Research Database (Denmark)

    Den Boer, Susanne Petronella A; Boomsma, Jacobus Jan; Baer, Boris

    2008-01-01

    The seminal fluid that accompanies sperm in ejaculates has been shown or suggested to affect sperm competition and paternity success of insects by preventing female remating, inducing oviposition, and forming mating plugs. In Atta leafcutter ants, queens have multiple mates but never remate later...... in life, although they may live and produce fertilized eggs for several decades. The mating biology and life history of these ants therefore suggests that the major function of seminal fluid is to maximize sperm viability during copulation, sperm transfer, and initial sperm storage. We tested...

  16. Self-restraint and sterility in workers of Acromyrmex and Atta leafcutter ants

    DEFF Research Database (Denmark)

    Dijkstra, Michiel Bendert; Nash, David Richard; Boomsma, Jacobus Jan

    2005-01-01

    Queens of leafcutter ants (Acromyrmex and Atta) are highly multiply mated, resulting in a potential queenworker and worker-worker conflict over who should produce the males in the colony. We studied whether this conflict is expressed, by determining the amount of reproductive egg-laying by workers....... octospinosus workers (n = 552), had ready-to-lay reproductive eggs. Old workers in all four species are incapable of laying eggs due to ovary resorption. We conclude that Atta workers are sterile, while Acromyrmex workers display reproductive self-restraint, possibly representing an earlier stage...

  17. Fungus gardens of the leafcutter ant Atta colombica function as egg nurseries for the snake Leptodeira annulata

    DEFF Research Database (Denmark)

    Baer, Boris; Den Boer, Susanne Petronella A; Kronauer, Daniel;

    2009-01-01

    by ant soldiers and that also newly hatched snakes manage to avoid ant attacks when they leaving their host colony. We speculate that L. annulata might use Atta and Acromyrmex leafcutter ant colonies as egg nurseries by some form of chemical insignificance, but more work is needed to understand...

  18. Magnetic anisotropy and organization of nanoparticles in heads and antennae of neotropical leaf-cutter ants, Atta colombica

    Science.gov (United States)

    Oriented magnetic nanoparticles have been suggested as a good candidate for a magnetic sensor in ants. Behavioral evidence for a magnetic compass in Neotropical leafcutter ants, Atta colombica (Formicidae: Attini), motivated a study of the arrangement of magnetic particles in the ants’ four major bo...

  19. Avaliação de sauveiros externos em eucaliptais de Minas Gerais

    Directory of Open Access Journals (Sweden)

    Iris Cristiane Magistrali

    2011-06-01

    Full Text Available Existe uma grande dificuldade em aperfeiçoar as técnicas de manejo de formigas cortadeiras, sobretudo no que diz respeito aos sauveiros externos localizados próximos a plantios florestais. Por causa disso, o presente trabalho teve por objetivo caracterizar aspectos como tamanho e distância de sauveiros externos em plantações de eucaliptos. A avaliação foi realizada em aceiros externos de três fazendas localizadas nos municípios de João Pinheiro e Buritizeiro, em Minas Gerais, seis meses após ser realizado o combate convencional às formigas cortadeiras. Foram encontrados nove sauveiros externos, com área média de terra solta de 62,5 ± 11,1 m2, localizados a uma distância média de 33,94 ± 8,68 metros entre a margem do plantio e o local do formigueiro. Constatou-se que tais características podem ser úteis no ajuste da largura da faixa de segurança de combate, a qual deve ser igual a 50 m. O gênero Trachymyrmex e as espécies Atta laevigata e Atta sexdens rubropilosa foram registrados como ocorrências novas no município de Buritizeiro, e o gênero Acromyrmex como uma nova ocorrência nos dois municípios.

  20. Mating biology of the leaf-cutting ants Atta colombica and A. cephalotes

    DEFF Research Database (Denmark)

    Baer, Boris; Boomsma, Jacobus J

    2006-01-01

    Copulation behavior has often been shaped by sexually selected sperm competition or cryptic female choice. However, manipulation of previously deposited ejaculates is unknown in the social Hymenoptera and the degree to which sperm competes after insemination or is actively selected by females has...... impossible, so we had to reconstruct the sequential copulation events by morphological analysis of the male and female genitalia and by tracking the process of sperm transfer and sperm storage. We show that Atta male genitalia have two external rows of spiny teeth, which fit into a specialized pouch organ...... in the female sexual tract. Reconstruction of the sperm storage process indicated that sperm is transferred to the spermatheca during or immediately after ejaculation and without being mixed with sperm and seminal fluids from other males. A convergent mechanism of direct sperm transfer to the spermatheca...

  1. Seminal fluid enhances sperm viability in the leafcutter ant Atta colombica

    DEFF Research Database (Denmark)

    Den Boer, Susanne Petronella A; Boomsma, Jacobus Jan; Baer, Boris

    2008-01-01

    in life, although they may live and produce fertilized eggs for several decades. The mating biology and life history of these ants therefore suggests that the major function of seminal fluid is to maximize sperm viability during copulation, sperm transfer, and initial sperm storage. We tested......The seminal fluid that accompanies sperm in ejaculates has been shown or suggested to affect sperm competition and paternity success of insects by preventing female remating, inducing oviposition, and forming mating plugs. In Atta leafcutter ants, queens have multiple mates but never remate later...... this hypothesis by comparing the viability of testis sperm and ejaculated sperm (mixed with seminal fluid) and found a significant positive effect of seminal fluid on sperm viability. We further quantified this positive effect by adding accessory gland secretion (a major component of seminal fluid) in a dilution...

  2. Diversity of Fungi Associated with Atta bisphaerica (Hymenoptera: Formicidae: The Activity of Aspergillus ochraceus and Beauveria bassiana

    Directory of Open Access Journals (Sweden)

    Myriam M. R. Ribeiro

    2012-01-01

    Full Text Available The grass-cutting ant Atta bisphaerica is one of the most serious pests in several pastures and crops in Brazil. Fungal diseases are a constant threat to these large societies composed of millions of closely related individuals. We investigated the occurrence of filamentous fungi associated with the ant A. bisphaerica in a pasture area of Viçosa, Minas Gerais State, Brazil. Several fungi species were isolated from forager ants, and two of them, known as entomopathogenic, Beauveria bassiana and Aspergillus ochraceus, were tested against worker ants in the laboratory. The two species were highly virulent, achieving 50 percent worker mortality within 4-5 days. It is the first time A. ochraceus, a commonly found fungal species, is reported to infect Atta species at a high prevalence. Possible uses for the fungus within biological control are discussed.

  3. Fungus gardens of the leafcutter ant Atta colombica function as egg nurseries for the snake Leptodeira annulata

    DEFF Research Database (Denmark)

    Baer, Boris; Den Boer, Susanne Petronella A; Kronauer, Daniel

    2009-01-01

    Attine ants are well known for their mutualistic symbiosis with fungus gardens, but many other symbionts and commensals have been described. Here, we report the discovery of two clusters of large snake eggs in neighboring fungus gardens of a mature Atta colombica colony. The eggs were completely...... embedded within the fungus garden and were ignored by the host ants, even when we placed them into another, freshly excavated fungus garden of the same colony. All five eggs contained embryos and two snakes eventually hatched, which we identified as being banded cat eyed snakes Leptodeira annulata L. Ant...... fungus gardens are likely to provide ideal climatic conditions for developing snake eggs and almost complete protection from egg predation. Our observations therefore indicate that mature banded cat eyed snakes are able to enter and oviposit in large and well defended Atta colonies without being attacked...

  4. Selective isolation of dematiaceous fungi from the workers of Atta laevigata (Formicidae: Attini).

    Science.gov (United States)

    Guedes, F L A; Attili-Angelis, D; Pagnocca, F C

    2012-01-01

    Leaf-cutting ants (Formicidae: Attini) are considered pests in agriculture for their impact in human crops, as they utilize leaf fragments to raise their fungal mutualist (Agaricales: Lepiotaceae). Basically, the basidiomycetous fungus is cultivated to supply food to adult workers and broads; in return, the ants protect it against natural enemies. However, recent studies have claimed that other microorganisms are associated to ant nests where a wide range of interactions may take place. To investigate the occurrence of dematiaceous fungi on the cuticle of Atta laevigata ants, 30 workers were sampled from an adult nest located in the surroundings of the Center for the Studies of Social Insects, UNESP-Rio Claro, SP, Brazil. The use of selective techniques to avoid high-sporulation fungi has been recommended and was tested in this study. To favor the isolation of the desired fungi, heads and cuticle scrapings of ant bodies were inoculated on Mycosel agar and incubated for 3 weeks at 35°C. Morphological and molecular methods were used to identify the filamentous fungi recovered. From 56 isolates, 19 were hyaline filamentous species, and among the remaining 37, some are mentioned as phyto-associated fungi like Alternaria arborescens, Bipolaris sorokiniana, Bipolaris eleusines, Bipolaris zeae, Curvularia trifolii, and Paraphaeosphaeria michotii. These species are reported from A. laevigata bodies for the first time. None of the isolation trials revealed the presence of the parasite Escovopsis or entomopathogenic fungi. The possible spread of the fungi in nature by the ants is discussed.

  5. The thermo-sensitive sensilla coeloconica of leaf-cutting ants (Atta vollenweideri).

    Science.gov (United States)

    Ruchty, Markus; Romani, Roberto; Kuebler, Linda S; Ruschioni, Sara; Roces, Flavio; Isidoro, Nunzio; Kleineidam, Christoph J

    2009-05-01

    Social insects show a variety of temperature-guided behaviors. Depending on whether heat reaches the sensillum via air movements (convective heat) or as radiant heat, specific adaptations of thermo-sensitive sensilla are expected. In the present study the morphology and the physiology of thermo-sensitive peg-in-pit sensilla (S. coeloconica) of the leaf-cutting ant Atta vollenweideri were investigated. S. coeloconica are located predominantly in a single cluster on the apical antennomere, and connect to the outside through a small aperture. The sensory peg is double-walled, embedded in a chamber and innervated by three unbranched dendrites. Using tungsten electrodes, activity of the sensory neurons was measured. In most cases, the neuron with the largest spike amplitude responds to changes in air temperature (convective heat) as well as to radiant heat. In response to a drop in air temperature, the neuron shows a phasic-tonic response followed by a complete adaptation within 1 min (cold-sensitive neuron). Based on their morphology and physiology, it is suggested that the S. coeloconica are involved in the recently described thermal orientation behavior of A. vollenweideri leaf-cutting ants.

  6. Hormigas zompopas (Atta cephalotes influyen positivamente en la biodiversidad vegetal de bosques húmedos tropicales

    Directory of Open Access Journals (Sweden)

    Javier Ruiz

    2010-08-01

    Full Text Available REALIZAMOS OBSERVACIONES DE LA HISTORIA NATURAL DE LA HORMIGA ZOMPOPA (Atta cephalotes en el período de 1995 a 2010. Monitoreamos una población de hormigas zompopas en 2003 y realizamos experimentos de campo en 2006 en el bosque húmedo tropical de la Estación Biológica La Unión en Nicaragua. Los nidos de hormiga zompopa fueron mapeados dentro de una parcela permanente de 6.5 hectáreas. Se estimó lacomposición de especies vegetales en el área del nido de la hormiga, y se realizó un conteo de plántulas dicotiledóneas y plántulas de palmas (monocotiledóneas. Los resultados indican que las hormigas zompopas prefieren defoliar plántulas de especies dicotiledóneas,favoreciendo la regeneración de palmas sobre el nido de las hormigas. Las zompopas favorecen la regeneración de palmas en áreas donde ellas establecen el montículo principal de sus nidos. En el artículo se discuten las implicaciones de estos resultados para la dinámicade la regeneración en bosques húmedos tropicales.

  7. Random sperm use and genetic effects on worker caste fate in Atta colombica leaf-cutting ants

    DEFF Research Database (Denmark)

    Holman, Luke; Stürup, Marlene; Trontti, Kalevi;

    2011-01-01

    genotyping revealed how sperm number translated into paternity of eggs and adult workers. We demonstrate that fertilization success is directly related to sperm numbers, that stored sperm are well-mixed and that egg paternity is constant over time. Moreover, worker size was found to have a considerable......Sperm competition can produce fascinating adaptations with far-reaching evolutionary consequences. Social taxa make particularly interesting models, because the outcome of sexual selection determines the genetic composition of groups, with attendant sociobiological consequences. Here, we use...... molecular tools to uncover some of the mechanisms and consequences of sperm competition in the leaf-cutting ant Atta colombica, a species with extreme worker size polymorphism. Competitive PCR allowed quantification of the relative numbers of sperm stored by queens from different males, and offspring...

  8. Association between Pseudonocardia symbionts and Atta leaf-cutting ants suggested by improved isolation methods

    OpenAIRE

    Marsh, Sarah E.; Poulsen, Michael; Gorosito, Norma B.; Pinto-Tomás, Adrián; Masiulionis, Virginia E. [UNESP; Currie, Cameron R

    2013-01-01

    Fungus-growing ants associate with multiple symbiotic microbes, including Actinobacteria for production of antibiotics. The best studied of these bacteria are within the genus Pseudonocardia, which in most fungus-growing ants are conspicuously visible on the external cuticle of workers. However, given that fungus-growing ants in the genus Atta do not carry visible Actinobacteria on their cuticle, it is unclear if this genus engages in the symbiosis with Pseudonocardia. Here we explore whether...

  9. The mitochondrial genome of the leaf-cutter ant Atta laevigata: a mitogenome with a large number of intergenic spacers.

    Directory of Open Access Journals (Sweden)

    Cynara de Melo Rodovalho

    Full Text Available In this paper we describe the nearly complete mitochondrial genome of the leaf-cutter ant Atta laevigata, assembled using transcriptomic libraries from Sanger and Illumina next generation sequencing (NGS, and PCR products. This mitogenome was found to be very large (18,729 bp, given the presence of 30 non-coding intergenic spacers (IGS spanning 3,808 bp. A portion of the putative control region remained unsequenced. The gene content and organization correspond to that inferred for the ancestral pancrustacea, except for two tRNA gene rearrangements that have been described previously in other ants. The IGS were highly variable in length and dispersed through the mitogenome. This pattern was also found for the other hymenopterans in particular for the monophyletic Apocrita. These spacers with unknown function may be valuable for characterizing genome evolution and distinguishing closely related species and individuals. NGS provided better coverage than Sanger sequencing, especially for tRNA and ribosomal subunit genes, thus facilitating efforts to fill in sequence gaps. The results obtained showed that data from transcriptomic libraries contain valuable information for assembling mitogenomes. The present data also provide a source of molecular markers that will be very important for improving our understanding of genomic evolutionary processes and phylogenetic relationships among hymenopterans.

  10. Specificity in chemical profiles of workers, brood and mutualistic fungi in Atta, Acromyrmex, and Sericomyrmex fungus-growing ants.

    Science.gov (United States)

    Richard, Freddie-Jeanne; Poulsen, Michael; Drijfhout, Falko; Jones, Graeme; Boomsma, Jacobus J

    2007-12-01

    Neotropical attine ants live in obligatory symbiosis with a fungus that they grow for food on a substrate of primarily plant material harvested by workers. Nestmate recognition is likely based on chemical cues as in most other social insects, but recent studies have indicated that both the ants and their mutualistic fungi may contribute to the recognition templates. To investigate the within-colony variation in chemical profiles, we extracted and identified compounds from the cuticle of workers, the postpharyngeal gland of workers, ant pupae and larvae, and the fungal symbiont of three species of higher attine ants: Atta colombica, Acromyrmex echinatior, and Sericomyrmex amabilis. The relative proportions of identified compounds were compared and represented 11 classes: n-alkanes, alkenes, branched methylalkanes, branched dimethylalkanes, trimethylalkanes, branched alkenes, aldehydes, alcohols, acetates, acids, and esters. The chemical profiles in all three species are likely to be sufficiently different to allow discrimination at the species and colony level and sufficiently similar within colonies to generate a relatively constant colony-specific chemical gestalt. The relative likelihood of individual compounds being derived from the ants, the ant brood, or the fungal symbiont are discussed. We hypothesize that hydrocarbons are particularly important as recognition cues because they appear to simultaneously allow the assessment of developmental stages and the identification of symbiont, colony, and species.

  11. Metarhizium anisopliae and Trichoderma viride control colonies of Atta cephalotes in field better than a chemical insecticide

    Directory of Open Access Journals (Sweden)

    Elkin López Arismendy

    2011-12-01

    Full Text Available The leaf-cutting ant Atta cephalotes is an economically important pest in agriculture. These ants use the material they cut to cultivate a fungus from which they fed. In this study, baits prepared with the entomopathogenic fungus Metarhizium anisopliae strain M-137, Trichoderma viride strain T-26, antagonist of the symbiont fungus of A. cephaloies, and a combination of both fungi were applied in order to control A. cephalotes colonies under field conditions. In addition, the insecticide activity of the baits was compared to a chemical product, Pirimifos Metil, which was applied with an air pump. The ants did not detect the fungal agents contained in the baits, and introduced then into their nests without awakening defensive behaviors. The mortality of the bait-treated nests was higher than 80% while the treatment with Pirimifos Metil was effective in only 60% of the nests. Additionally, a week after the application of these treatments, changes in the insects' behavior were observed, reflected mainly in the absence of foraging activity. In conclusion, M. anisopliae was effective in controlling A. cephalotes colonies, and superior to the chemical product Pirimifos Metil. 

  12. Fungal communities in gardens of the leafcutter ant Atta cephalotes in forest and cabruca agrosystems of southern Bahia State (Brazil).

    Science.gov (United States)

    Reis, Bárbara Monique dos Santos; Silva, Aline; Alvarez, Martín Roberto; Oliveira, Tássio Brito de; Rodrigues, Andre

    2015-12-01

    Leaf-cutting ants interact with several fungi in addition to the fungal symbiont they cultivate for food. Here, we assessed alien fungal communities in colonies of Atta cephalotes. Fungus garden fragments were sampled from colonies in the Atlantic Rainforest and in a cabruca agrosystem in the state of Bahia (Brazil) in two distinct periods to evaluate whether differences in nest habitat influence the diversity of fungi in the ant colonies. We recovered a total of 403 alien fungi isolates from 628 garden fragments. The prevalent taxa found in these samples were Escovopsis sp. (26 %), Escovopsioides nivea (24 %), and Trichoderma spirale (10.9 %). Fungal diversity was similar between the colonies sampled in both areas suggesting that ants focus on reducing loads of alien fungi in the fungus gardens instead of avoiding specific fungi. However, fungal taxa composition differed between colonies sampled in the two areas and between the sampling periods. These differences are likely explained by the availability of plant substrates available for foraging over habitats and periods. Ordination analysis further supported that sampling period was the main attribute for community structuring but also revealed that additional factors may explain the structuring of fungal communities in colonies of A. cephalotes.

  13. How load-carrying ants avoid falling over: mechanical stability during foraging in Atta vollenweideri grass-cutting ants.

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    Karin Moll

    Full Text Available BACKGROUND: Foraging workers of grass-cutting ants (Atta vollenweideri regularly carry grass fragments larger than their own body. Fragment length has been shown to influence the ants' running speed and thereby the colony's food intake rate. We investigated whether and how grass-cutting ants maintain stability when carrying fragments of two different lengths but identical mass. PRINCIPAL FINDINGS: Ants carried all fragments in an upright, backwards-tilted position, but held long fragments more vertically than short ones. All carrying ants used an alternating tripod gait, where mechanical stability was increased by overlapping stance phases of consecutive steps. The overlap was greatest for ants carrying long fragments, resulting in more legs contacting the ground simultaneously. For all ants, the projection of the total centre of mass (ant and fragment was often outside the supporting tripod, i.e. the three feet that would be in stance for a non-overlapping tripod gait. Stability was only achieved through additional legs in ground contact. Tripod stability (quantified as the minimum distance of the centre of mass to the edge of the supporting tripod was significantly smaller for ants with long fragments. Here, tripod stability was lowest at the beginning of each step, when the center of mass was near the posterior margin of the supporting tripod. By contrast, tripod stability was lowest at the end of each step for ants carrying short fragments. Consistently, ants with long fragments mainly fell backwards, whereas ants carrying short fragments mainly fell forwards or to the side. Assuming that transporting ants adjust neither the fragment angle nor the gait, they would be less stable and more likely to fall over. CONCLUSIONS: In grass-cutting ants, the need to maintain static stability when carrying long grass fragments has led to multiple kinematic adjustments at the expense of a reduced material transport rate.

  14. Spatio-Temporal Dynamics of Foraging Networks in the Grass-Cutting Ant Atta bisphaerica Forel, 1908 (Formicidae, Attini).

    Science.gov (United States)

    Lopes, Juliane F S; Brugger, Mariana S; Menezes, Regys B; Camargo, Roberto S; Forti, Luiz Carlos; Fourcassié, Vincent

    2016-01-01

    Foraging networks are a key element for ant colonies because they facilitate the flow of resources from the environment to the nest and they allow the sharing of information among individuals. Here we report the results of an 8-month survey, extending from November 2009 to June 2010, of the foraging networks of four mature colonies of Atta bisphaerica, a species of grass-cutting ant which is considered as a pest in Brazil. We found that the distribution of foraging effort was strongly influenced by the landscape features around the nests, in particular by the permanently wet parts of the pasture in which the nests were located. The foraging networks consisted of underground tunnels which opened on average at 21.5m from the nests and of above-ground physical trails that reached on average 4.70m in length. The use of the foraging networks was highly dynamic, with few sections of the networks used for long periods of time. Three different phases, which could be linked to the seasonal change in the local rainfall regime, could be identified in the construction and use of the foraging networks. The first phase corresponded to the beginning of the rainy season and was characterized by a low foraging activity, as well as a low excavation and physical trail construction effort. The second phase, which began in February and extended up to the end of the humid season at the end of March, was characterized by an intense excavation and trail construction effort, resulting in an expansion of the foraging networks. Finally, in the third phase, which corresponded to the beginning of the dry season, the excavation and trail construction effort leveled off or decreased while foraging activity kept increasing. Our hypothesis is that ants could benefit from the underground tunnels and physical trails built during the humid season to maintain their foraging activity at a high level.

  15. Magnetic anisotropy and organization of nanoparticles in heads and antennae of neotropical leaf-cutter ants, Atta colombica

    Science.gov (United States)

    Alves, Odivaldo C.; Srygley, Robert B.; Riveros, Andre J.; Barbosa, Marcia A.; Esquivel, Darci M. S.; Wajnberg, Eliane

    2014-10-01

    Oriented magnetic nanoparticles have been suggested as a good candidate for a magnetic sensor in ants. Behavioural evidence for a magnetic compass in neotropical leaf-cutter ants, Atta colombica (Formicidae: Attini), motivated a study of the arrangement of magnetic particles in the ants’ four major body parts by measuring the angular dependence of the ferromagnetic resonance spectra at room temperature. Spectra of the thoraces and those of the abdomens showed no significant angular dependence, while those of the antennae and those of the heads exhibited a periodic dependence relative to the magnetic field. Fitting of the angular dependence of the resonant field resulted in an unexpected magnetic anisotropy with uniaxial symmetry. High values of the first order anisotropy constant were observed for the magnetic material in antennae (-2.9  ×  105 erg cm-3) and heads (-1  ×  106 erg cm-3) as compared to body parts of other social insects. In addition, the magnitude of the anisotropy in the heads was comparable to that observed in magnetite nanoparticles of 4-5 nm diameter. For the antennae, the mean angle of the particles’ easy magnetization axis (EA) was estimated to be 41° relative to the straightened antenna’s long axis. For the heads, EA was approximately 60° relative to the head’s axis running from midway between the spines to the clypeus. These physical characteristics indicate organized magnetic nanoparticles with a potential for directional sensitivity, which is an important feature of magnetic compasses.

  16. The genome sequence of the leaf-cutter ant Atta cephalotes reveals insights into its obligate symbiotic lifestyle.

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    Garret Suen

    Full Text Available Leaf-cutter ants are one of the most important herbivorous insects in the Neotropics, harvesting vast quantities of fresh leaf material. The ants use leaves to cultivate a fungus that serves as the colony's primary food source. This obligate ant-fungus mutualism is one of the few occurrences of farming by non-humans and likely facilitated the formation of their massive colonies. Mature leaf-cutter ant colonies contain millions of workers ranging in size from small garden tenders to large soldiers, resulting in one of the most complex polymorphic caste systems within ants. To begin uncovering the genomic underpinnings of this system, we sequenced the genome of Atta cephalotes using 454 pyrosequencing. One prediction from this ant's lifestyle is that it has undergone genetic modifications that reflect its obligate dependence on the fungus for nutrients. Analysis of this genome sequence is consistent with this hypothesis, as we find evidence for reductions in genes related to nutrient acquisition. These include extensive reductions in serine proteases (which are likely unnecessary because proteolysis is not a primary mechanism used to process nutrients obtained from the fungus, a loss of genes involved in arginine biosynthesis (suggesting that this amino acid is obtained from the fungus, and the absence of a hexamerin (which sequesters amino acids during larval development in other insects. Following recent reports of genome sequences from other insects that engage in symbioses with beneficial microbes, the A. cephalotes genome provides new insights into the symbiotic lifestyle of this ant and advances our understanding of host-microbe symbioses.

  17. Ants can learn to forage on one-way trails.

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    Pedro Leite Ribeiro

    Full Text Available The trails formed by many ant species between nest and food source are two-way roads on which outgoing and returning workers meet and touch each other all along. The way to get back home, after grasping a food load, is to take the same route on which they have arrived from the nest. In many species such trails are chemically marked by pheromones providing orientation cues for the ants to find their way. Other species rely on their vision and use landmarks as cues. We have developed a method to stop foraging ants from shuttling on two-way trails. The only way to forage is to take two separate roads, as they cannot go back on their steps after arriving at the food or at the nest. The condition qualifies as a problem because all their orientation cues -- chemical, visual or any other -- are disrupted, as all of them cannot but lead the ants back to the route on which they arrived. We have found that workers of the leaf-cutting ant Atta sexdens rubropilosa can solve the problem. They could not only find the alternative way, but also used the unidirectional traffic system to forage effectively. We suggest that their ability is an evolutionary consequence of the need to deal with environmental irregularities that cannot be negotiated by means of excessively stereotyped behavior, and that it is but an example of a widespread phenomenon. We also suggest that our method can be adapted to other species, invertebrate and vertebrate, in the study of orientation, memory, perception, learning and communication.

  18. The Postpharyngeal Gland: Specialized Organ for Lipid Nutrition in Leaf-Cutting Ants

    Science.gov (United States)

    Decio, Pâmela; Vieira, Alexsandro Santana; Dias, Nathalia Baptista; Palma, Mario Sergio; Bueno, Odair Correa

    2016-01-01

    There are several hypotheses about the possible functions of the postpharyngeal gland (PPG) in ants. The proposed functions include roles as cephalic or gastric caeca and diverticulum of the digestive tract, mixing of hydrocarbons, nestmate recognition, feeding larvae, and the accumulation of lipids inside this gland, whose origin is contradictory. The current study aimed to investigate the functions of these glands by examining the protein expression profile of the PPGs of Atta sexdens rubropilosa (Hymenoptera, Formicidae). Mated females received lipid supplementation and their glands were extracted and analyzed using a proteomic approach. The protocol used combined two-dimensional electrophoresis and shotgun strategies, followed by mass spectrometry. We also detected lipid β-oxidation by immunofluorescent marking of acyl-CoA dehydrogenase. Supplying ants with lipids elicited responses in the glandular cells of the PPG; these included increased expression of proteins related to defense mechanisms and signal transduction and reorganization of the cytoskeleton due to cell expansion. In addition, some proteins in PPG were overexpressed, especially those involved in lipid and energy metabolism. Part of the lipids may be reduced, used for the synthesis of fatty alcohol, transported to the hemolymph, or may be used as substrate for the synthesis of acetyl-CoA, which is oxidized to form molecules that drive oxidative phosphorylation and produce energy for cellular metabolic processes. These findings suggest that this organ is specialized for lipid nutrition of adult leaf-cutting ants and characterized like a of diverticulum foregut, with the ability to absorb, store, metabolize, and mobilize lipids to the hemolymph. However, we do not rule out that the PPG may have other functions in other species of ants. PMID:27149618

  19. Response of the grass-cutting ant Atta capiguara Gonçalves, 1944 (Hymenoptera: Formicidae to sugars and artificial sweeteners Resposta da saúva Atta capiguara Gonçalves, 1944 (Hymenoptera: Formicidae a açúcares e edulcorantes artificiais

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    Maria Aparecida Castellani Boaretto

    2003-01-01

    Full Text Available Using of toxic baits made of dehydrated citric pulp to control grass-cutting ants can lead to unsatisfactory results because of the low attractiveness of the substrate to worker ants. This work aimed to identify attractive substances, with potential for incorporation in a matrix of granulated baits for grass-cutting ants, among several kinds of sugars and substances used in artificial sweeteners. Experiments were carried out in mature nests of Atta capiguara (Hym.: Formicidae set in pasture. Studied substances were sucrose, fructose, soluble starch, raffinose, maltose, lactose, sorbose, cellobiose, arabinose, xylose, glucose, galactose, rhamnose, arabinose, melezitose, saccharine and cyclamate (at 5.0% w/v. Later, on maltose, xylose, sucrose, fructose and glucose solutions were included at 5.0%, 7.5%, 10.0% and 20.0% w/v, respectively. Cellulose rectangles were used as vehicle and number of rectangles carried into the colonies was evaluated. Carrying rates were very low with maximum means of 9.6% for lactose and 6.0% for arabinose and cyclamate, at the 5.0% concentration. No differences (P > 0.05 were observed relatively to the control (distilled water. No effects were detected for solution, concentration and for the interaction of these factors. Sugars and artificial sweeteners studied were not attractive to Atta capiguara workers, turning their inclusion as attractants in toxic ant baits not viable.O uso de iscas tóxicas, formuladas à base de polpa cítrica desidratada, para o controle de formigas cortadeiras de gramíneas pode levar a resultados insatisfatórios devido à baixa atratividade do substrato às operárias. Este trabalho foi realizado com o objetivo de identificar substâncias atrativas e com potencial para incorporação em matrizes de iscas granuladas para formigas cortadeiras de gramíneas, dentre diversos tipos de açúcares e edulcorantes artificiais. Os experimentos foram realizados em ninhos adultos de Atta capiguara Gon

  20. Cellulose-Enriched Microbial Communities from Leaf-Cutter Ant (Atta colombica Refuse Dumps Vary in Taxonomic Composition and Degradation Ability.

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    Gina R Lewin

    Full Text Available Deconstruction of the cellulose in plant cell walls is critical for carbon flow through ecosystems and for the production of sustainable cellulosic biofuels. Our understanding of cellulose deconstruction is largely limited to the study of microbes in isolation, but in nature, this process is driven by microbes within complex communities. In Neotropical forests, microbes in leaf-cutter ant refuse dumps are important for carbon turnover. These dumps consist of decaying plant material and a diverse bacterial community, as shown here by electron microscopy. To study the portion of the community capable of cellulose degradation, we performed enrichments on cellulose using material from five Atta colombica refuse dumps. The ability of enriched communities to degrade cellulose varied significantly across refuse dumps. 16S rRNA gene amplicon sequencing of enriched samples identified that the community structure correlated with refuse dump and with degradation ability. Overall, samples were dominated by Bacteroidetes, Gammaproteobacteria, and Betaproteobacteria. Half of abundant operational taxonomic units (OTUs across samples were classified within genera containing known cellulose degraders, including Acidovorax, the most abundant OTU detected across samples, which was positively correlated with cellulolytic ability. A representative Acidovorax strain was isolated, but did not grow on cellulose alone. Phenotypic and compositional analyses of enrichment cultures, such as those presented here, help link community composition with cellulolytic ability and provide insight into the complexity of community-based cellulose degradation.

  1. Pathogen-induced binding of the soybean zinc finger homeodomain proteins GmZF-HD1 and GmZF-HD2 to two repeats of ATTA homeodomain binding site in the calmodulin isoform 4 (GmCaM4) promoter.

    Science.gov (United States)

    Park, Hyeong Cheol; Kim, Man Lyang; Lee, Sang Min; Bahk, Jeong Dong; Yun, Dae-Jin; Lim, Chae Oh; Hong, Jong Chan; Lee, Sang Yeol; Cho, Moo Je; Chung, Woo Sik

    2007-01-01

    Calmodulin (CaM) is involved in defense responses in plants. In soybean (Glycine max), transcription of calmodulin isoform 4 (GmCaM4) is rapidly induced within 30 min after pathogen stimulation, but regulation of the GmCaM4 gene in response to pathogen is poorly understood. Here, we used the yeast one-hybrid system to isolate two cDNA clones encoding proteins that bind to a 30-nt A/T-rich sequence in the GmCaM4 promoter, a region that contains two repeats of a conserved homeodomain binding site, ATTA. The two proteins, GmZF-HD1 and GmZF-HD2, belong to the zinc finger homeodomain (ZF-HD) transcription factor family. Domain deletion analysis showed that a homeodomain motif can bind to the 30-nt GmCaM4 promoter sequence, whereas the two zinc finger domains cannot. Critically, the formation of super-shifted complexes by an anti-GmZF-HD1 antibody incubated with nuclear extracts from pathogen-treated cells suggests that the interaction between GmZF-HD1 and two homeodomain binding site repeats is regulated by pathogen stimulation. Finally, a transient expression assay with Arabidopsis protoplasts confirmed that GmZF-HD1 can activate the expression of GmCaM4 by specifically interacting with the two repeats. These results suggest that the GmZF-HD1 and -2 proteins function as ZF-HD transcription factors to activate GmCaM4 gene expression in response to pathogen.

  2. Diploid male production in a leaf-cutting ant

    DEFF Research Database (Denmark)

    Armitage, S.; Boomsma, J.; Baer, Boris

    2010-01-01

    1. In haplodiploid social insects where males are haploid and females are diploid, inbreeding depression is expressed as the production of diploid males when homozygosity at the sex-determining locus results in the production of diploid individuals with a male phenotype. Diploid males are often...... assumed to have reduced fitness compared with their haploid brothers. 2. While studying the reproductive biology of a leaf-cutting ant, Atta sexdens, in Gamboa, Republic of Panama, we detected the presence of a larger male morph. Using microsatellite markers we were able to confirm that the large male...... that many diploid male larvae may not survive to adulthood. 4. We measured two traits potentially linked to male reproductive success: sperm length and sperm number, and showed that diploid males produced fewer but longer sperm. These results provide indirect evidence that diploid male reproductive success...

  3. Foraging leaf-cutting ants learn to reject Vitis vinifera ssp. vinifera plants that emit herbivore-induced volatiles.

    Science.gov (United States)

    Thiele, Theresa; Kost, Christian; Roces, Flavio; Wirth, Rainer

    2014-06-01

    Leaf-cutting ants (LCAs) are dominant herbivores of the Neotropics, as well as economically important pests. Their foraging ecology and patterns/mechanisms of food selection have received considerable attention. Recently, it has been documented that LCAs exhibit a delayed rejection of previously accepted food plants following treatment with a fungicide that makes the plants unsuitable as substrate for their symbiotic fungus. Here, we investigated whether LCAs similarly reject plants with induced chemical defenses, by combining analysis of volatile emissions with dual-choice bioassays that used LCA subcolonies (Atta sexdens L.). On seven consecutive days, foraging ants were given the choice between leaf disks from untreated control plants and test plants of Vitis vinifera ssp. vinifera L. treated with the phytohormone jasmonic acid (JA) to mimic herbivore attack. Chemical analysis revealed the emission of a characteristic set of herbivore-induced volatile organic compounds (VOC) from JA-induced plants. Dual-choice experiments indicated that workers did not show any preference initially, but that they avoided JA-treated plants from day five onwards. Our finding that A. sexdens foragers learn to avoid VOC-emitting plants, which are likely detrimental to their symbiotic fungus, represents the first evidence for avoidance learning in attine ants toward plants with induced defenses.

  4. Starch metabolism in Leucoagaricus gongylophorus, the symbiotic fungus of leaf-cutting ants.

    Science.gov (United States)

    Silva, A; Bacci, M; Pagnocca, F C; Bueno, O C; Hebling, M J A

    2006-01-01

    Leucoagaricus gongylophorus, the symbiotic fungus of the leaf-cutting ants, degrades starch, this degradation being supposed to occur in the plant material which leafcutters forage to the nests, generating most of the glucose which the ants utilize for food. In the present investigation, we show that laboratory cultures of L. gongylophorus produce extracellular alpha-amylase and maltase which degrade starch to glucose, reinforcing that the ants can obtain glucose from starch through the symbiotic fungus. Glucose was found to repress alpha-amylase and, more severely, maltase activity, thus repressing starch degradation by L. gongylophorus, so that we hypothesize that: (1) glucose down-regulation of starch degradation also occurs in the Atta sexdens fungus garden; (2) glucose consumption from the fungus garden by A. sexdens stimulates degradation of starch from plant material by L. gongylophorus, which may represent a mechanism by which leafcutters can control enzyme production by the symbiotic fungus. Since glucose is found in the fungus garden inside the nests, down-regulation of starch degradation by glucose is supposed to occur in the nest and play a part in the control of fungal enzyme production by leafcutters.

  5. Seed dispersal and predation of Buchenavia tomentosa Eichler (Combretaceae in a Cerrado sensu stricto, midwest Brazil

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    J. Farias

    Full Text Available Abstract The ecology of seed dispersal is critical to understand the patterns of distribution and abundance of plant species. We investigated seed dispersal aspects associated with the high abundance of Buchenavia tomentosa in the Serra Azul State Park (PESA. We estimated fruit production and conducted fruit removal experiments. We carried out diurnal and nocturnal observations on frugivory as well as germination tests. Fruiting occurred in the dry season and totaled 1,365,015 ± 762,670 fruits.ha–1. B. tomentosa fruits were utilized by eight animal species. The lowland tapir (Tapirus terrestris was considered the main seed disperser. Leafcutter ants (Atta laevigata and Atta sexdens participated in the seed cleaning and occasionally dispersed seeds. The beetle Amblycerus insuturatus, blue-and-yellow macaw (Ara ararauna and red-and-green macaw (Ara chloropterus were considered pre-dispersal seed predators. The seeds manually cleaned presented higher germination rate (100% and speed index (4.2 seeds.d–1 than that of seeds with pulp. Germination of seeds found in tapirs’feces was 40%, while for the seeds without pulp it was 25%. The high abundance of B. tomentosa in the cerrado of PESA may be due to massive fruit production, low rates of seed predation, and efficient seed dispersal by tapirs, occurring before the rains which promote germination and recruitment of this species.

  6. Seed dispersal and predation of Buchenavia tomentosa Eichler (Combretaceae) in a Cerrado sensu stricto, midwest Brazil.

    Science.gov (United States)

    Farias, J; Sanchez, M; Abreu, M F; Pedroni, F

    2015-11-01

    The ecology of seed dispersal is critical to understand the patterns of distribution and abundance of plant species. We investigated seed dispersal aspects associated with the high abundance of Buchenavia tomentosa in the Serra Azul State Park (PESA). We estimated fruit production and conducted fruit removal experiments. We carried out diurnal and nocturnal observations on frugivory as well as germination tests. Fruiting occurred in the dry season and totaled 1,365,015 ± 762,670 fruits.ha-1. B. tomentosa fruits were utilized by eight animal species. The lowland tapir (Tapirus terrestris) was considered the main seed disperser. Leafcutter ants (Atta laevigata and Atta sexdens) participated in the seed cleaning and occasionally dispersed seeds. The beetle Amblycerus insuturatus, blue-and-yellow macaw (Ara ararauna) and red-and-green macaw (Ara chloropterus) were considered pre-dispersal seed predators. The seeds manually cleaned presented higher germination rate (100%) and speed index (4.2 seeds.d-1) than that of seeds with pulp. Germination of seeds found in tapirs'feces was 40%, while for the seeds without pulp it was 25%. The high abundance of B. tomentosa in the cerrado of PESA may be due to massive fruit production, low rates of seed predation, and efficient seed dispersal by tapirs, occurring before the rains which promote germination and recruitment of this species.

  7. Variation in male body size and reproductive allocation in the leafcutter ant Atta colombica

    DEFF Research Database (Denmark)

    Stürup, M.; den Boer, S. P. A.; Nash, David Richard

    2011-01-01

    Remarkably little is known about the traits that determine reproductive success of males in eusocial insects. Their window for mate choice decisions is very short, the actual mating process is very difficult to observe, and their small body sizes have likely prevented systematic studies in many...... are traits directly correlated with reproductive success. However, the much higher heritabilities for total body mass, gaster mass, head width, sperm length and sperm number suggest that these traits are less likely to make direct contributions to male fitness....

  8. Secondary seed dispersal of Ricinus communis Linnaeus (Euphorbiaceae by ants in secondary growth vegetation in Minas Gerais Dispersão secundária de sementes de Ricinus communis Linnaeus (Euphorbiaceae por formigas em vegetação secundária em Minas Gerais

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    Mário Marcos do Espírito Santo

    2007-12-01

    Full Text Available In this study, I tested the efficacy of ants as secondary seed dispersers of Ricinus communis in southeastern Brazil. In a natural population of 143 individuals, I determined the ballistic dispersal distance for 62 seeds and 100 additional seeds were experimentally offered to ants in groups of ten seeds along a transect of 50 m. Fifty-three seeds were removed by ants, mainly by the leafcutter Atta sexdens (90.4%. The dispersal distance by ants was high, compared to the global average (4.38 m ± 0.74 m vs. 0.96 m, but was lower than the ballistic distance (7.27 m ± 0.13 m. Ants increased the total dispersal distance (8.66 m ± 0.60 m, but the main benefit for the plant was the directed dispersal, with seed deposition on the enriched soil of ant nests.Este estudo testou a eficiência de formigas como dispersores secundários de Ricinus communis no Brasil. Em uma população natural de 143 indivíduos, a distância de dispersão balística foi determinada para 62 sementes. Além disso, 100 sementes adicionais foram oferecidas a formigas em grupos de 10, ao longo de um transecto de 50 m. Cinqüenta e três sementes foram removidas por formigas, principalmente pela formiga-cortadeira Atta sexdens (90,4%. A distância de dispersão por formigas foi alta se comparada à média global (4,38m ± 0,74 m vs. 0,96 m, porém menor que a distância de dispersão balística (7,27 m ± 0,13 m. As formigas aumentaram a distância de dispersão total (8,66 m ± 0,60 m, mas o principal benefício para a planta foi a dispersão direcionada, com a deposição das sementes no solo enriquecido encontrado nos ninhos das formigas.

  9. A metabolic pathway assembled by enzyme selection may support herbivory of leaf-cutter ants on plant starch.

    Science.gov (United States)

    Bacci, Maurício; Bueno, Odair Correa; Rodrigues, André; Pagnocca, Fernando Carlos; Somera, Alexandre Favarin; Silva, Aline

    2013-05-01

    Mutualistic associations shape the evolution in different organism groups. The association between the leaf-cutter ant Atta sexdens and the basidiomycete fungus Leucoagaricus gongylophorus has enabled them to degrade starch from plant material generating glucose, which is a major food source for both mutualists. Starch degradation is promoted by enzymes contained in the fecal fluid that ants deposit on the fungus culture in cut leaves inside the nests. To understand the dynamics of starch degradation in ant nests, we purified and characterized starch degrading enzymes from the ant fecal fluid and from laboratory cultures of L. gongylophorus and found that the ants intestine positively selects fungal α-amylase and a maltase likely produced by the ants, as a negative selection is imposed to fungal maltase and ant α-amylases. Selected enzymes are more resistant to catabolic repression by glucose and proposed to structure a metabolic pathway in which the fungal α-amylase initiates starch catalysis to generate byproducts which are sequentially degraded by the maltase to produce glucose. The pathway is responsible for effective degradation of starch and proposed to represent a major evolutionary innovation enabling efficient starch assimilation from plant material by leaf-cutters.

  10. Identification and expression of capa gene in the fire ant, Solenopsis invicta.

    Science.gov (United States)

    Choi, Man-Yeon; Köhler, Rene; Vander Meer, Robert K; Neupert, Susanne; Predel, Reinhard

    2014-01-01

    Recent genome analyses suggested the absence of a number of neuropeptide genes in ants. One of the apparently missing genes was the capa gene. Capa gene expression in insects is typically associated with the neuroendocrine system of abdominal ganglia; mature CAPA peptides are known to regulate diuresis and visceral muscle contraction. The apparent absence of the capa gene raised questions about possible compensation of these functions. In this study, we re-examined this controversial issue and searched for a potentially unrecognized capa gene in the fire ant, Solenopsis invicta. We employed a combination of data mining and a traditional PCR-based strategy using degenerate primers designed from conserved amino acid sequences of insect capa genes. Our findings demonstrate that ants possess and express a capa gene. As shown by MALDI-TOF mass spectrometry, processed products of the S. invicta capa gene include three CAPA periviscerokinins and low amounts of a pyrokinin which does not have the C-terminal WFGPRLa motif typical of CAPA pyrokinins in other insects. The capa gene was found with two alternative transcripts in the CNS. Within the ventral nerve cord, two capa neurons were immunostained in abdominal neuromeres 2-5, respectively, and projected into ventrally located abdominal perisympathetic organs (PSOs), which are the major hormone release sites of abdominal ganglia. The ventral location of these PSOs is a characteristic feature and was also found in another ant, Atta sexdens.

  11. Identification and expression of capa gene in the fire ant, Solenopsis invicta.

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    Man-Yeon Choi

    Full Text Available Recent genome analyses suggested the absence of a number of neuropeptide genes in ants. One of the apparently missing genes was the capa gene. Capa gene expression in insects is typically associated with the neuroendocrine system of abdominal ganglia; mature CAPA peptides are known to regulate diuresis and visceral muscle contraction. The apparent absence of the capa gene raised questions about possible compensation of these functions. In this study, we re-examined this controversial issue and searched for a potentially unrecognized capa gene in the fire ant, Solenopsis invicta. We employed a combination of data mining and a traditional PCR-based strategy using degenerate primers designed from conserved amino acid sequences of insect capa genes. Our findings demonstrate that ants possess and express a capa gene. As shown by MALDI-TOF mass spectrometry, processed products of the S. invicta capa gene include three CAPA periviscerokinins and low amounts of a pyrokinin which does not have the C-terminal WFGPRLa motif typical of CAPA pyrokinins in other insects. The capa gene was found with two alternative transcripts in the CNS. Within the ventral nerve cord, two capa neurons were immunostained in abdominal neuromeres 2-5, respectively, and projected into ventrally located abdominal perisympathetic organs (PSOs, which are the major hormone release sites of abdominal ganglia. The ventral location of these PSOs is a characteristic feature and was also found in another ant, Atta sexdens.

  12. Variation in male body size and reproductive allocation in the leafcutter ant Atta colombica

    DEFF Research Database (Denmark)

    Stürup, M.; den Boer, S. P. A.; Nash, David Richard;

    2011-01-01

    Remarkably little is known about the traits that determine reproductive success of males in eusocial insects. Their window for mate choice decisions is very short, the actual mating process is very difficult to observe, and their small body sizes have likely prevented systematic studies in many...

  13. Natural enemies of Atta vollenweideri (Hymenoptera: Formicidae) leaf-cutter ants negatively affected by synthetic pesticides, chlorpyrifos and fipronil.

    Science.gov (United States)

    Guillade, Andrea C; Folgarait, Patricia J

    2014-02-01

    In southern South America, Ada vollenweideri Forel (Hymenoptera: Formicidae) is a significant pest of several crops and forestry, also considered to reduce the carrying capacity of pastures. The most usual control method used in Latin America is the application of synthetic pesticides, mainly chlorpyrifos and fipronil. However, no studies have assessed the effects of these agrochemicals on natural enemies of ants. We aimed to evaluate the efficiency of these pesticides on leaf-cutter ants' control and to test their effect on phorid fly parasitoids. Chlorpyrifos failed to exert complete control over ant colonies in the field and was gravely detrimental to specific parasitoids, reducing their percentage of parasitism, pupal survivorship, and adult longevity. Fipronil, however, exerted complete control over the treated colonies. Laboratory tests using both pesticides, either on ants from foraging trails or on pupariae, showed that chlorpyrifos and fipronil decreased larval and pupal survivorship, as well as adult longevity of parasitoids, in comparison to controls. In conclusion, these pesticides will likely affect parasitoids with regard to their reproductive capacity, leading to the decreased levels of natural parasitism observed in the field after treatments. We discuss why neither pesticide should be taken into account for integrated pest management programs.

  14. Ethnopharmacological survey among migrants living in the Southeast Atlantic Forest of Diadema, São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Rodrigues Eliana

    2010-10-01

    Full Text Available Abstract Background Understanding how people of diverse cultural backgrounds have traditionally used plants and animals as medicinal substances during displacements is one of the most important objectives of ethnopharmacological studies. An ethnopharmacological survey conducted among migrants living in the Southeast Atlantic Forest remnants (Diadema, São Paulo, Brazil is presented herein. Methods Ethnographical methods were used to select and interview the migrants, and botanical and zoological techniques were employed to collect the indicated resources. Results We interviewed five migrants who described knowledge on 12 animals and 85 plants. Only 78 plants were present in Diadema, they belong to 37 taxonomic families; 68 were used exclusively for medicinal purposes, whereas 10 were reported to be toxic and/or presented some restriction of use. These taxa were grouped into 12 therapeutic categories (e.g., gastrointestinal disturbances, inflammatory processes or respiratory problems based on the 41 individual complaints cited by the migrants. While the twelve animal species were used by the migrants to treat nine complaints; these were divided into six categories, the largest of which related to respiratory problems. None of the animal species and only 57 of the 78 plant species analysed in the present study were previously reported in the pharmacological literature; the popular knowledge concurred with academic findings for 30 of the plants. The seven plants [Impatiens hawkeri W. Bull., Artemisia canphorata Vill., Equisetum arvensis L., Senna pendula (Humb. & Bonpl. ex Willd. H.S. Irwin & Barneby, Zea mays L., Fevillea passiflora Vell. and Croton fuscescens Spreng] and the two animals (Atta sexdens and Periplaneta americana that showed maintenance of use among migrants during their displacement in Brazilian territory, have not been studied by pharmacologists yet. Conclusions Thus, they should be highlighted and focused in further pharmacology

  15. Protein content of leaf-cutting ant queens before the nuptial flight and during the post-claustral phase

    Directory of Open Access Journals (Sweden)

    Edypo Jacob Silva

    2014-12-01

    Full Text Available Protein content of leaf-cutting ant queens before the nuptial flight and during the post-claustral phase. This study evaluated the crude protein content of queens of Atta sexdens before the nuptial flight and after the claustral phase in laboratory and field colonies. The hypothesis was that protein is used for survival of the queen and for early colony growth during the claustral phase. Additionally, the nest morphology, live biomass and adult population of field colonies were evaluated. Crude protein was determined by digestion of the organic material with sulfuric acid at high temperatures. The mean crude protein content was 123.23 ± 11.20 mg for females before the nuptial flight and 70.44 ± 12.21 mg for laboratory-reared queens after the claustral phase. The post-claustral crude protein content of field-collected queen was 55.90 ± 9.18 mg. With respect to the loss of crude protein as a function of duration of the claustral phase, laboratory-reared queens lost 52.79 mg and field-collected queens lost 67.33 mg compared to females before the nuptial flight. A positive linear correlation was observed between the weight of field-collected queens (256.4 ± 36.3 mg and colony biomass (13.02 ± 9.12 g, but there was no correlation between biomass and nest depth (13.11 ± 3.82 cm. As expected, the present results support the hypothesis that protein is used for survival of the queen and for early colony growth, as demonstrated by the reduction in crude protein content as a function of duration of the claustral phase. To our knowledge, this is the first study to provide data of the dynamics of protein reserves in leaf-cutting ant queens during the claustral phase.

  16. Are ant assemblages of Brazilian veredas characterised by location or habitat type?

    Directory of Open Access Journals (Sweden)

    CB Costa-Milanez

    Full Text Available Wetland areas in the Brazilian Cerrado, known as “veredas”, represent ecosystems formed on sandy soils with high concentrations of peat, and are responsible for the recharge of aquiferous reservoirs. They are currently under threat by various human activities, most notably the clearing of vegetation for Eucalyptus plantations. Despite their ecological importance and high conservation value, little is known about the actual effects of human disturbance on the animal community. To assess how habitat within different veredas, and plantations surrounding them affect ant assemblages, we selected four independent vereda locations, two being impacted by Eucalyptus monoculture (one younger and one mature plantation and two controls, where the wetland was surrounded by cerrado vegetation. Ant sampling was conducted in May 2010 (dry season using three complementary methods, namely baits, pitfall traps, and hand collection, in the wetland and in the surrounding habitats. A total of 7,575 ants were sampled, belonging to seven subfamilies, 32 genera and 124 species. Ant species richness and abundance did not differ between vereda locations, but did between the habitats. When impacted by the monoculture, ant species richness and abundance decreased in wetlands, but were less affected in the cerrado habitat. Ant species composition differed between the three habitats and between vereda locations. Eucalyptus plantations had an ant species composition defined by high dominance of Pheidole sp. and Solenopsis invicta, while natural habitats were defined by Camponotus and Crematogaster species. Atta sexdens was strictly confined to native habitats of non-impacted “veredas”. Eucalyptus monocultures require high quantities of water in the early stages, which may have caused a decrease in groundwater level in the wetland, allowing hypogeic ants such as Labidus praedator to colonise this habitat.

  17. Rapid shifts in Atta cephalotes fungus-garden enzyme activity after a change in fungal substrate (Attini, Formicidae)

    DEFF Research Database (Denmark)

    Kooij, P W; Schiøtt, M; Boomsma, J J;

    2011-01-01

    the backbone structure of pectin molecules, relative to a pure diet of bramble leaves, and this happened predominantly in the most recently established top sections of fungus gardens. However, fungus-garden amylase activity did not significantly increase despite the substantial increase in starch availability......Fungus gardens of the basidiomycete Leucocoprinus gongylophorus sustain large colonies of leaf-cutting ants by degrading the plant material collected by the ants. Recent studies have shown that enzyme activity in these gardens is primarily targeted toward starch, proteins and the pectin matrix...... activity to provide a better match with substrate availability and that excess starch that is not protected by cell walls may be digested by the ants rather than by the fungus-garden symbiont. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00040-010-0127-9) contains...

  18. Local distortion of the earth’s magnetic field as a proposal for handling the leafcutter ant species Atta spp. (Hymenoptera: Formicidae

    Directory of Open Access Journals (Sweden)

    Hernán Paz Penagos

    2012-08-01

    Full Text Available Studies regarding the spatial orientation of social insects (bees, termites and ants concerning their search for food, foraging and transporting it have received considerable attention during the last few years. Such studies have been aimed at learning so as to apply it to robotics (multiagents and ecological pest control. However, little is known about the types of orientation mechanism and their integration in such insects. This article presents some geomagnetic field detection studies dealing with controlling them by magnetotaxis or orientation experiments in Sasaima (Cundinamarca to formulate an ecological management proposal for ants from this species which greatly affect Colombian agriculture.

  19. Association between Pseudonocardia symbionts and Atta leaf-cutting ants suggested by improved isolation methods

    DEFF Research Database (Denmark)

    Marsh, Sarah E.; Poulsen, Michael; Gorosito, Norma B.;

    2013-01-01

    Fungus-growing ants associate with multiple symbiotic microbes, including Actinobacteria for production of antibiotics. The best studied of these bacteria are within the genus Pseudonocardia, which in most fungus-growing ants are conspicuously visible on the external cuticle of workers. However, ...

  20. Specificity in chemical profiles of workers, brood and mutualistic fungi in Atta, Acromyrmex, and Sericomyrmex fungus-growing ants

    DEFF Research Database (Denmark)

    Richard, Freddie-Jeanne; Poulsen, Michael; Drijfhout, Falko

    2007-01-01

    , acids, and esters. The chemical profiles in all three species are likely to be sufficiently different to allow discrimination at the species and colony level and sufficiently similar within colonies to generate a relatively constant colony-specific chemical gestalt. The relative likelihood of individual...... compounds being derived from the ants, the ant brood, or the fungal symbiont are discussed. We hypothesize that hydrocarbons are particularly important as recognition cues because they appear to simultaneously allow the assessment of developmental stages and the identification of symbiont, colony...

  1. Dicty_cDB: Contig-U03534-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available |||||||| Sbjct: 121 tcgnattcccaaagtcaattgttagaaattagaacagttggnggtctatttgctggtatt 180 Query: 181 cnattgnatcacaatgtaagtgatttggtttcan...||||| Sbjct: 181 cnattgnatcacaatgtaagtgatttggtttcanatgctaaatctcaaaanattttaatc 240...tagaaattagaacagttggnggtctatttgctggtatt 66 Query: 181 cnattgnatcacaatgtaagtgatttggtttcan...cnattgnatcacaatgtaagtgatttggtttcanatgctaaatctcaaaanattttaatc 6 Query: 241 atta 244 |||| Sbjct: 5 atta 2 Lamb

  2. 排球比赛中三号位进攻战术变化的分析%The Analysis of the Atta quant Assistant’s Offensive Tactics In the Volleyball Game

    Institute of Scientific and Technical Information of China (English)

    陈珂; 何利民

    2015-01-01

    随着排球技战术的飞速发展,进攻技战术呈现出多样性和复杂性,这也就对3号位队员的战术变化提出了更高的要求。通过对大量文献的查阅,发现目前学者主要针对快球的拦网技术和3号位队员进攻战术意识的培养进行研究,但对于二者的结合使用研究较少。研究采用文献资料法、专家访谈法、录像观察法,针对拦网战术对3号位进攻战术变化进行了分析研究,为排球比赛中提高3号位的进攻战术变化提供了理论依据。%With the rapid development of volleyball skills and tactics, Attacking Tactics showing the diversity and complexity, this means three position players on the tactical changes put forward higher requirements. Based on the extensive literature of inspection, found that the current scholars focused on fast balls and three position players blocking technology offensive tactical awareness training study, But few studies using a combination of both. Through literature, expert interviews, video observation, III position for blocking tactics offensive tactics for change were analyzed, a theoretical basis.

  3. Differences in forage-acquisition and fungal enzyme activity contribute to niche segregation in Panamanian leaf-cutting ants

    DEFF Research Database (Denmark)

    Kooij, Pepijn Wilhelmus; Liberti, Joanito; Giampoudakis, Konstantinos;

    2014-01-01

    activities of twelve fungus garden decomposition enzymes, belonging to the amylases, cellulases, hemicellulases, pectinases and proteinases, and show that average enzyme activity per unit of fungal mass in Atta gardens is lower than in Acromyrmex gardens. Expression profiles of fungal enzymes in Atta also...... for decomposition enzymes....

  4. Toxicological impact of Amaranth, Sunset Yellow and Curcumin as food coloring agents in albino rats

    Directory of Open Access Journals (Sweden)

    JPMS

    2011-10-01

    Full Text Available Mohamed M.Hashem, Attia H.Atta, Mahmoud S. Arbid, Somaia A. Nada, Samar M. Mouneir and Gihan Farag Asaad (Department of Pharmacology, Faculty of Veterinary Medicine, Cairo University, Giza, Egypt (pages 43-51

  5. Identificación de las feromonas de trilla de hormigas cortadoras (formicidae: attini1

    Directory of Open Access Journals (Sweden)

    Oscar Marino Mosquera

    2010-05-01

    Full Text Available Del extracto en diclorometano de las glándulas de veneno de las hormigas cortadoras: Atta laevigata, Atta bisphaerica, Acromyrmex subterraneus molestans. Fueron analizados por CG y CG-EM e identificados el 4-metilpirrol-2-carboxilato de metilo y el 3-etil-2,5-dimetilpirazina como los compuestos principales de la feromona de trilla (marcación de camino.

  6. TANGR2015 Heidelberg. Second international workshop on tracer applications of noble gas radionuclides in the geosciences

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2015-07-01

    TANGR2015 is a workshop on the progress in the technique and application of Atom Trap Trace Analyis (ATTA). It is a follow-up to the first TANGR workshop, TANGR2012, which was held at the Argonne National Laboratory, Argonne, USA, in June 2012. It is organized in response to recent technical advances and new applications of Atom Trap Trace Analysis (ATTA), an analytical method for measuring the isotopes {sup 81}Kr, {sup 85}Kr, and {sup 39}Ar. The primary aim of the workshop is to discuss the technical progress of ATTA and thereby enable innovative and timely applications of the noble gas radionuclides to important scientific problems in earth and environmental sciences, e.g. in the fields of groundwater hydrology, glaciology, oceanography, and paleoclimatology.

  7. Differences in forage-acquisition and fungal enzyme activity contribute to niche segregation in Panamanian leaf-cutting ants.

    Directory of Open Access Journals (Sweden)

    Pepijn W Kooij

    Full Text Available The genera Atta and Acromyrmex are often grouped as leaf-cutting ants for pest management assessments and ecological surveys, although their mature colony sizes and foraging niches may differ substantially. Few studies have addressed such interspecific differences at the same site, which prompted us to conduct a comparative study across six sympatric leaf-cutting ant species in Central Panama. We show that foraging rates during the transition between dry and wet season differ about 60 fold between genera, but are relatively constant across species within genera. These differences appear to match overall differences in colony size, especially when Atta workers that return to their nests without leaves are assumed to carry liquid food. We confirm that Panamanian Atta specialize primarily on tree-leaves whereas Acromyrmex focus on collecting flowers and herbal leaves and that species within genera are similar in these overall foraging strategies. Species within genera tended to be spaced out over the three habitat categories that we distinguished (forest, forest edge, open grassland, but each of these habitats normally had only a single predominant Atta and Acromyrmex species. We measured activities of twelve fungus garden decomposition enzymes, belonging to the amylases, cellulases, hemicellulases, pectinases and proteinases, and show that average enzyme activity per unit of fungal mass in Atta gardens is lower than in Acromyrmex gardens. Expression profiles of fungal enzymes in Atta also appeared to be more specialized than in Acromyrmex, possibly reflecting variation in forage material. Our results suggest that species- and genus-level identities of leaf-cutting ants and habitat-specific foraging profiles may give predictable differences in the expression of fungal genes coding for decomposition enzymes.

  8. Grab a Golgi: Laser trapping of golgi bodies reveals in vivo Interactions with the endoplasmic reticulum

    NARCIS (Netherlands)

    Sparkes, I.A.; Ketelaar, T.; Ruijter, de N.C.A.; Hawes, C.

    2009-01-01

    In many vacuolate plant cells individual Golgi bodies appear to be attached to tubules of the pleiomorphic cortical endoplasmic reticulum (ER) network. Such observations culminated in the controversial mobile secretory unit hypothesis to explain transport of cargo from the ER to Golgi via Golgi atta

  9. Eosinophilic esophagitis: A newly established cause of dysphagia

    OpenAIRE

    Yan, Brian M; Shaffer, Eldon A.

    2006-01-01

    Eosinophilic esophagitis has rapidly become a recognized entity causing dysphagia in young adults. This review summarizes the current knowledge of eosinophilic esophagitis including the epidemiology, clinical presentation, diagnostic criteria, pathophysiology, treatment, and prognosis. An extensive search of PubMed/Medline (1966-December 2005) for available English literature in humans for eosinophilic esophagitis was completed. Appropriate articles listed in the bibliographies were also atta...

  10. The Shock and Vibration Digest. Volume 13, Number 3

    Science.gov (United States)

    1981-03-01

    Flight, MppIM.it 198U) N8030000 Kay Word«: Vibration •«citation. Human ratpont« Elavan wbiacu wara vibratad on a ihaka- tabla in the tra- quancy...ranga of 2 Hi to 19 Hi to attaM tha complax haad motion inducad by i^ xii machantcat vibration. Accalaratlon ampiltuda Mat tinuioidal and ha)d

  11. Predicting extreme loads effects on wind turbines considering uncertainty in airfoil data

    DEFF Research Database (Denmark)

    Abdallah, Imad; Natarajan, Anand; Sørensen, John Dalsgaard

    2013-01-01

    The sources contributing to uncertainty in a wind turbine blade static airfoil data include wind tunnel testing, CFD calculations, 3D rotational corrections based on CFD or empirical models, surface roughness corrections, Reynolds number corrections, expansion to the full 360-degree angle of atta...

  12. Complete Genome of Enterobacteriaceae Bacterium Strain FGI 57, a Strain Associated with Leaf-Cutter Ant Fungus Gardens.

    Science.gov (United States)

    Aylward, Frank O; Tremmel, Daniel M; Bruce, David C; Chain, Patrick; Chen, Amy; Walston Davenport, Karen; Detter, Chris; Han, Cliff S; Han, James; Huntemann, Marcel; Ivanova, Natalia N; Kyrpides, Nikos C; Markowitz, Victor; Mavrommatis, Kostas; Nolan, Matt; Pagani, Ioanna; Pati, Amrita; Pitluck, Sam; Deshpande, Shweta; Goodwin, Lynne; Woyke, Tanja; Currie, Cameron R

    2013-01-01

    The Enterobacteriaceae bacterium strain FGI 57 was isolated from a fungus garden of the leaf-cutter ant Atta colombica. Analysis of its single 4.76-Mbp chromosome will shed light on community dynamics and plant biomass degradation in ant fungus gardens.

  13. DoD Technology Management in a Global Technology Environment

    Science.gov (United States)

    2005-05-01

    Atta, Michael Lippitz, Jasper Lupo , Rob Mahoney, Jack Nunn, Transformation and Transition: DARPA’s Role in Fostering an Emerging Revolution in...Michael Lippitz, Jasper Lupo , Rob Mahoney, Jack Nunn, Transformation and Transition: DARPA’s Role in Fostering an Emerging Revolution in Military

  14. Biomolecular sensing using surface micromachined silicon plates

    NARCIS (Netherlands)

    Zapata, A.M.; Carlen, E.T.; Kim, E.S.; Hsiao, J.; Traviglia, D.; Weinberg, M.S.; Delapierre, G.; Puers, R.

    2007-01-01

    Micromachined sensors to detect surface stress changes associated with interactions between an immobilized chemically selective receptor and a target analyte are presented. The top isolated sensing surface of a free-standing silicon plate is prepared with a thin Au layer, followed by a covalent atta

  15. Has substrate-dependent co-evolution of enzyme function occured in the attine ant-fungus symbiosis

    DEFF Research Database (Denmark)

    de Fine Licht, Henrik Hjarvard; Schiøtt, Morten; Boomsma, Jacobus Jan

    The conspicuous leaf-cutter ants in the genus Atta build huge nests displacing several cubic meters of soil, whereas lower attine genera such as Cyphomyrmex have small nests with a fungus garden the size of a table-tennis ball. Only the leaf-cutter ants are specialized on using fresh leaves...

  16. The ejaculatory biology of leafcutter ants

    DEFF Research Database (Denmark)

    den Boer, Susanne; Stürup, Marlene; Boomsma, Jacobus Jan

    2015-01-01

    understanding of the fundamental biology of ejaculate production, transfer and physiological function remains extremely limited. We studied the ejaculation process in the leafcutter ant Atta colombica and found that it starts with the appearance of a clear pre-ejaculatory fluid (PEF) at the tip...

  17. News Round-Up

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Prof.Atta Mills, President of Ghana "The presence of the oil in Nzemaland in Western Ghana is God’s gratitude to Dr.Nkrumah." Foreign firms ultimatum Sudan Sudanese President Omar al-Bashir threatened to expel any foreign organization that does not respect the country’s

  18. Medium-dose riboflavin as a prophylactic agent in children with migraine: A preliminary placebo-controlled, randomised, double-blind, cross-over trial

    NARCIS (Netherlands)

    J.K.J. Bruijn (Jacques); H.J. Duivenvoorden (Hugo); J. Passchier (Jan); H. Locher (Heiko); N. Dijkstra (Natascha); W.F.M. Arts (Willem Frans)

    2010-01-01

    textabstractBackground: Riboflavin seems to have a promising effect on migraine in adults. The present study examines whether riboflavin has a prophylactic effect on migraine in children. Objective: To investigate whether riboflavin in a dosage of 50 mg/day has a prophylactic effect on migraine atta

  19. Chromatin Flavors: Chromatin composition and domain organization in Drosophila melanogaster

    NARCIS (Netherlands)

    J.G. van Bemmel (Joke)

    2012-01-01

    textabstractChromatin was originally identified by W. Flemming in 1882 as not much more than the stainable substance of the cell nucleus. Flemming named this substance according to the Greek word “chroma”, meaning color. In 1911 chromatin was characterized as proteins, named histones, that were atta

  20. Assessment of crop growth and water productivity for five C3 species in semi-arid Inner Mongolia

    NARCIS (Netherlands)

    Yuan, M.; Zhang, L.; Gou, F.; Su, Z.; Spiertz, J.H.J.; Werf, van der W.

    2013-01-01

    Water availability is a key biophysical factor determining agricultural production potential. The FAO crop water response model AquaCrop was developed to estimate crop production under water limiting conditions. This model uses the normalized water productivity, WP* (g m-2 d-1), to estimate the atta

  1. A New Method of Measuring 81Kr and 85Kr Abundances in Environmental Samples

    CERN Document Server

    Du, X; Bailey, K; Lehmann, B E; Lorenzo, R; Lu, Z T; Müller, P; O'Connor, T P; Sturchio, N C; Young, L

    2003-01-01

    We demonstrate a new method for determining the 81Kr/Kr ratio in environmental samples based upon two measurements: the 85Kr/81Kr ratio measured by Atom Trap Trace Analysis (ATTA) and the 85Kr/Kr ratio measured by Low-Level Counting (LLC). This method can be used to determine the mean residence time of groundwater in the range of 10^5 - 10^6 a. It requires a sample of 100 micro-l STP of Kr extracted from approximately two tons of water. With modern atmospheric Kr samples, we demonstrate that the ratios measured by ATTA and LLC are directly proportional to each other within the measurement error of +/- 10%; we calibrate the 81Kr/Kr ratio of modern air measured using this method; and we show that the 81Kr/Kr ratios of samples extracted from air before and after the development of the nuclear industry are identical within the measurement error.

  2. Near field measurements on contrail properties from fuels with different sulfur content

    Energy Technology Data Exchange (ETDEWEB)

    Petzold, A. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Physik der Atmosphaere; Busen, R. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Physik der Atmosphaere; Schroeder, F.P. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Physik der Atmosphaere; Baumann, R. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Physik der Atmosphaere; Kuhn, M. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Physik der Atmosphaere; Stroem, J. [Stockholm Univ. (Sweden). Dept. of Meteorology; Hagen, D.E. [Missouri Univ., Rolla, MO (United States); Whitefield, P.D. [Missouri Univ., Rolla, MO (United States); Baumgardner, D. [National Center for Atmospheric Research, Boulder, Colorado (United States); Arnold, F. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany). Bereich Atmosphaerenphysik; Borrmann, S. [Mainz Univ. (Germany). Inst. fuer Physik der Atmosphaere; Schumann, U. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Physik der Atmosphaere

    1997-08-01

    Microphysical properties of jet engine exhaust aerosol and contrails were studied in the near field of the emitting aircraft for different fuel sulfur contents. Measurements were performed behind the research aircraft ATTAS of DLR and an Airbus A310-300 using fuels with different sulfur contents of 6 ppm and 2700 ppm. The major differences in accumulation mode aerosol and microphysical contrail properties between the used aircraft were an increased number concentration of both the accumulation mode aerosol and the contrail particles in the Airbus A310-300 plume compared to the ATTAS plume. Part of the difference in contrail particles may be caused by different ambient conditions, but the major differences are assumed to be caused by different engine properties. (orig.)

  3. Los estados inmaduros de Coelosis biloba (Coleoptera: Melolonthidae: Dynastinae y notas sobre su biología Immature stages of Coelosis biloba (Coleoptera: Melolonthidae: Dynastinae with notes on their biology

    Directory of Open Access Journals (Sweden)

    Luis Carlos Pardo-Locarno

    2006-12-01

    Full Text Available Se describen la larva de tercer estadio y las pupas de macho y hembra de Coelosis biloba (Linné 1767 con ejemplares recolectados en Colombia (Cauca y Valle y en México (Veracruz asociados con los hormigueros de Atta cephalotes (Linné 1750. Se incluyen ilustraciones de las estructuras diagnósticas, una clave para separar las larvas de tercer estadio hasta ahora conocidas de la tribu Oryctini en América, y observaciones sobre la biología de C. biloba como inquilino de los nidos de hormigas.The larva of third instar, male and female pupae of Coelosis biloba obtained inside ant nests of Atta cephalotes in Colombia (Cauca, Valle and Mexico (Veracruz are described. Drawings of diagnostic structures, a key to the known third instar larvae of American Oryctini, and observations on the biology of C. biloba as inquiline of ant nests, are included.

  4. Afghanistan: Post-Taliban Governance, Security, and U.S. Policy

    Science.gov (United States)

    2016-06-06

    Congressional Research Service 4 Rashid Dostam—who joined prominent mujahedin commander Ahmad Shah Masoud of the Islamic Society, a largely Tajik party...Northern Alliance was the Uzbek militia (the Junbush-Melli, or National Islamic Movement of Afghanistan) of General Abdul Rashid Dostam. Frequently...reconstituting militia forces are Balkh Province governor Atta Mohammad Noor, Herat leader Ismail Khan, and first Vice President Abdul Rashid Dostam

  5. Environmental Assessment for the Expansion of the Elmendorf AFB Gravel Pit

    Science.gov (United States)

    2008-04-01

    Conservation 333 Raspberry Rd Anchorage AK 99518- 5519 Chris Nahorney Alaska Department of Natural Resources Division of Mining, Land, and Water 550 W...atta6men 1 ). The existing grd\\’e) pi I woultl cxp~tnd eastward to t1le boutldary llc1wcc,..’"l\\ Fori Richardson aud Elmendorf :\\PB, inc:ea.~inp, in si:.rc

  6. Comportamento e dieta alimentar de uma espécie de Latrodectus do grupo Mactans (Araneae, Theridiidae) em cativeiro Behavior and diet supply of Latrodectus group Mactans (Araneae, Theridiidae) in captivity

    OpenAIRE

    Maria de Fátima da Rocha Dias; Tania Kobler Brazil

    1999-01-01

    Latrodectus gr. mactans is responsible for 28% of ali accidents provoked by spiders in state of Bahia, Brazil (1980-1990), which makes necessary the study of its manejament. The spiders were captured in Ondina, Salvador, and in Baxio, Esplanada (Bahia, Brazil); they were mantained in captivity, with food supply weekly (Atta sp., larva of Tenebrio sp. and Drosophila melanogaster) with three hours/ offers observation time, during march/95 to april/96. In captivity, the spiders accepted two kind...

  7. Synthesis, Interdiction, and Protection of Layered Networks

    Science.gov (United States)

    2009-09-01

    relationships to interdict (represented by maximizing the shortest path) is found to be the following: Abdul Aziz Al-Omari to Marwan Al-Shehhi, Abdul Aziz Al...1 46 Khalid Al-M ihdhar 1 47 1 56 Majed Moqed 1 54 1 80 Marwan Al-Shehhi 1 37 1 46 Mohamed Atta 1 35 1 49 Mohand Alsheri 1 50 1 59 Nawaf Alhazmi 1 35

  8. An Examination of the Critical Factors of Store Brand Purchase Intentions

    OpenAIRE

    Zhao, Xiaoqian

    2011-01-01

    Consumer behaviour is very complex interaction of affect, cognition, behaviour and environment activities, which deals with how and why individuals conduct the exchange events of products and service. Brand, as a signal of quality assurance and sometimes a symbol of identity, plays a significant role in consumer decision making process. Thus build up brand assets and improve brand equity is important in brand management. As a main source of consumer packaged goods, store brands should be atta...

  9. Household Coverage of Fortified Staple Food Commodities in Rajasthan, India

    Science.gov (United States)

    Aaron, Grant J.; Sodani, Prahlad R.; Sankar, Rajan; Fairhurst, John; Siling, Katja; Guevarra, Ernest; Norris, Alison; Myatt, Mark

    2016-01-01

    A spatially representative statewide survey was conducted in Rajasthan, India to assess household coverage of atta wheat flour, edible oil, and salt. An even distribution of primary sampling units were selected based on their proximity to centroids on a hexagonal grid laid over the survey area. A sample of n = 18 households from each of m = 252 primary sampling units PSUs was taken. Demographic data on all members of these households were collected, and a broader dataset was collected about a single caregiver and a child in the first 2 years of life. Data were collected on demographic and socioeconomic status; education; housing conditions; recent infant and child mortality; water, sanitation, and hygiene practices; food security; child health; infant and young child feeding practices; maternal dietary diversity; coverage of fortified staples; and maternal and child anthropometry. Data were collected from 4,627 households and the same number of caregiver/child pairs. Atta wheat flour was widely consumed across the state (83%); however, only about 7% of the atta wheat flour was classified as fortifiable, and only about 6% was actually fortified (mostly inadequately). For oil, almost 90% of edible oil consumed by households in the survey was classified as fortifiable, but only about 24% was fortified. For salt, coverage was high, with almost 85% of households using fortified salt and 66% of households using adequately fortified salt. Iodized salt coverage was also high; however, rural and poor population groups were less likely to be reached by the intervention. Voluntary fortification of atta wheat flour and edible oil lacked sufficient industry consolidation to cover significant portions of the population. It is crucial that appropriate delivery channels are utilized to effectively deliver essential micronutrients to at-risk population groups. Government distribution systems are likely the best means to accomplish this goal. PMID:27760123

  10. Guide for the Development of Safety Assessment Report (SAR)

    Science.gov (United States)

    1987-08-01

    smoke grenade and associated launchers. c. Describe operating environments and specific skills for safe operation, maintenance, or disposal. 2 4. Describe...as a result of the design or use of the system. AttaOh OTSG Health Hazard Assesment (AR 40-10). 5. Conclusions and -ecommendations. a. State whethvr...FOR THE j XM52 SMOKE GENERATOR MAY 1984 CONCURRED BY; CONCURRED BY: D-2 SUBJECT: Safety Assessment Report for XM52 Smoke Generator 1.0 INTRODUCTION

  11. Control Structures in supply chains as a way to manage unpredictable cyber-risks

    OpenAIRE

    Sepúlveda Estay, Daniel Alberto; Khan, Omera

    2016-01-01

    Supply chain growth, and their dependence on Information Technology (IT), is making cyber risks an increasingly unmanageable threat through traditional risk assessment methods. Systemic analysis methods have been identified as alternatives to trad itional methods. This paper analyzes the application of a systemic risk analysis methodology to understand cyber risks in the supply chain. A generic supply chain is analyzed, and information flows, dynamic structures and the influence of cyber-atta...

  12. Automated Vision Test Development and Validation

    Science.gov (United States)

    2016-11-01

    AFRL-SA-WP-SR-2016-0020 Automated Vision Test Development and Validation Steve Wright, Darrell Rousse, Alex van Atta...Special Report 3. DATES COVERED (From – To) April 2014 – April 2015 4. TITLE AND SUBTITLE Automated Vision Test Development and Validation 5a...23 Nov 2016. 14. ABSTRACT The Optec Vision Test , originally produced in 1951 as the Armed Forces Vision Tester, is the sole device used to qualify

  13. Tracer Applications of Noble Gas Radionuclides in the Geosciences

    CERN Document Server

    Lu, Z -T; Smethie, W M; Sturchio, N C; Fischer, T P; Kennedy, B M; Purtschert, R; Severinghaus, J P; Solomon, D K; Tanhua, T; Yokochi, R

    2013-01-01

    The noble gas radionuclides, including 81Kr (half-life = 229,000 yr), 85Kr (11 yr), and 39Ar (269 yr), possess nearly ideal chemical and physical properties for studies of earth and environmental processes. Recent advances in Atom Trap Trace Analysis (ATTA), a laser-based atom counting method, have enabled routine measurements of the radiokrypton isotopes, as well as the demonstration of the ability to measure 39Ar in environmental samples. Here we provide an overview of the ATTA technique, and a survey of recent progress made in several laboratories worldwide. We review the application of noble gas radionuclides in the geosciences and discuss how ATTA can help advance these fields, specifically determination of groundwater residence times using 81Kr, 85Kr, and 39Ar; dating old glacial ice using 81Kr; and an 39Ar survey of the main water masses of the oceans, to study circulation pathways and estimate mean residence times. Other scientific questions involving deeper circulation of fluids in the Earth's crust ...

  14. Metagenomic and metaproteomic insights into bacterial communities in leaf-cutter ant fungus gardens

    Energy Technology Data Exchange (ETDEWEB)

    Aylward, Frank O.; Burnum, Kristin E.; Scott, Jarrod J.; Suen, Garret; Tringe, Susannah G.; Adams, Sandra M.; Barry, Kerrie W.; Nicora, Carrie D.; Piehowski, Paul D.; Purvine, Samuel O.; Starrett, Gabriel J.; Goodwin, Lynne A.; Smith, Richard D.; Lipton, Mary S.; Currie, Cameron R.

    2012-09-01

    Herbivores gain access to nutrients stored in plant biomass largely by harnessing the metabolic activities of microbes. Leaf-cutter ants of the genus Atta are a hallmark example; these dominant Neotropical herbivores cultivate symbiotic fungus gardens on massive quantities of fresh plant forage. As the external digestive system of the ants, fungus gardens facilitate the production and sustenance of millions of workers in mature Atta colonies. Here we use metagenomic, and metaproteomic techniques to characterize the bacterial diversity and overall physiological potential of fungus gardens from two species of Atta. Our analysis of over 1.2 Gbp of community metagenomic sequence and three 16S pyrotag libraries reveals that, in addition to harboring the dominant fungal crop, these ecosystems contain abundant populations of Enterobacteriaceae, including the genera Enterobacter, Pantoea, Klebsiella, Citrobacter, and Escherichia. We show that these bacterial communities possess genes commonly associated with lignocellulose degradation, and likely participate in the processing of plant biomass. Additionally, we demonstrate that bacteria in these environments encode a diverse suite of biosynthetic pathways, and that they may enrich the nitrogen-poor forage of the ants with B-vitamins, amino acids, and proteins. These results are consistent with the hypothesis that fungus gardens are highly-specialized fungus-bacteria communities that efficiently convert plant material into usable energy for their ant hosts. Together with recent investigations into the microbial symbionts of vertebrates, our work underscores the importance of microbial communities to the ecology and evolution of herbivorous metazoans.

  15. Functional role of phenylacetic acid from metapleural gland secretions in controlling fungal pathogens in evolutionarily derived leaf-cutting ants.

    Science.gov (United States)

    Fernández-Marín, Hermógenes; Nash, David R; Higginbotham, Sarah; Estrada, Catalina; van Zweden, Jelle S; d'Ettorre, Patrizia; Wcislo, William T; Boomsma, Jacobus J

    2015-05-22

    Fungus-farming ant colonies vary four to five orders of magnitude in size. They employ compounds from actinomycete bacteria and exocrine glands as antimicrobial agents. Atta colonies have millions of ants and are particularly relevant for understanding hygienic strategies as they have abandoned their ancestors' prime dependence on antibiotic-based biological control in favour of using metapleural gland (MG) chemical secretions. Atta MGs are unique in synthesizing large quantities of phenylacetic acid (PAA), a known but little investigated antimicrobial agent. We show that particularly the smallest workers greatly reduce germination rates of Escovopsis and Metarhizium spores after actively applying PAA to experimental infection targets in garden fragments and transferring the spores to the ants' infrabuccal cavities. In vitro assays further indicated that Escovopsis strains isolated from evolutionarily derived leaf-cutting ants are less sensitive to PAA than strains from phylogenetically more basal fungus-farming ants, consistent with the dynamics of an evolutionary arms race between virulence and control for Escovopsis, but not Metarhizium. Atta ants form larger colonies with more extreme caste differentiation relative to other attines, in societies characterized by an almost complete absence of reproductive conflicts. We hypothesize that these changes are associated with unique evolutionary innovations in chemical pest management that appear robust against selection pressure for resistance by specialized mycopathogens.

  16. Grain size stabilization of nanocrystalline copper at high temperatures by alloying with tantalum

    Energy Technology Data Exchange (ETDEWEB)

    Darling, K.A., E-mail: kristopher.darling.civ@mail.mil [U.S. Army Research Laboratory, Weapons and Materials Research Directorate, Aberdeen Proving Ground, MD 21005-5069 (United States); Roberts, A.J. [ORISE Program, U.S. Army Research Laboratory, Aberdeen Proving Ground, MD 21005-5069 (United States); Mishin, Y. [George Mason University, Dept of Physics and Astronomy, Fairfax, VA 22030 (United States); Mathaudhu, S.N. [U.S. Army Research Laboratory, Army Research Office, Research Triangle Park, NC 27709-2211 (United States); Kecskes, L.J. [U.S. Army Research Laboratory, Weapons and Materials Research Directorate, Aberdeen Proving Ground, MD 21005-5069 (United States)

    2013-10-05

    Highlights: •A mean grain size of 167 nm is retained after annealing at 97% of the melting point. •Hardness surpasses conventional pure nanocrystalline Cu by 2.5 GPa. •Extreme stability is attributed to both thermodynamic and kinetic stabilization. -- Abstract: Nanocrystalline Cu–Ta alloys belong to an emerging class of immiscible materials with potential for high-temperature applications. Differential scanning calorimetry (DSC), Vickers microhardness, transmission and scanning electron microscopy (TEM/SEM), and atomistic simulations have been applied to study the structural evolution in high-energy cryogenically alloyed nanocrystalline Cu–10 at.%Ta. The thermally induced coarsening of the as-milled microstructure was investigated and it was found that the onset of grain growth occurs at temperatures higher than that for pure nanocrystalline Cu. The total heat release associated with grain growth was 0.553 kJ/mol. Interestingly, nanocrystalline Cu–10 at.%Ta maintains a mean grain size (GS) of 167 nm after annealing at 97% of its melting point. The increased microstructural stability is attributed to a combination of thermodynamic and kinetic stabilization effects which, in turn, appear to be controlled by segregation and diffusion of Ta solute atoms along grain boundaries (GBs). The as-milled nanocrystalline Cu–10 at.%Ta exhibits Vickers microhardness values near 5 GPa surpassing the microhardness of conventional pure nanocrystalline Cu by ∼2.5 GPa.

  17. Extended-Range Passive RFID and Sensor Tags

    Science.gov (United States)

    Fink, Patrick W.; Kennedy, Timothy F.; Lin, Gregory Y.; Barton, Richard

    2012-01-01

    Extended-range passive radio-frequency identification (RFID) tags and related sensor tags are undergoing development. A tag of this type incorporates a retroreflective antenna array, so that it reflects significantly more signal power back toward an interrogating radio transceiver than does a comparable passive RFID tag of prior design, which does not incorporate a retroreflective antenna array. Therefore, for a given amount of power radiated by the transmitter in the interrogating transceiver, a tag of this type can be interrogated at a distance greater than that of the comparable passive RFID or sensor tag of prior design. The retroreflective antenna array is, more specifically, a Van Atta array, named after its inventor and first published in a patent issued in 1959. In its simplest form, a Van Atta array comprises two antenna elements connected by a transmission line so that the signal received by each antenna element is reradiated by the other antenna element (see Figure 1). The phase relationships among the received and reradiated signals are such as to produce constructive interference of the reradiated signals; that is, to concentrate the reradiated signal power in a direction back toward the source. Hence, an RFID tag equipped with a Van Atta antenna array automatically tracks the interrogating transceiver. The effective gain of a Van Atta array is the same as that of a traditional phased antenna array having the same number of antenna elements. Additional pairs of antenna elements connected by equal-length transmission lines can be incorporated into a Van Atta array to increase its directionality. Like some RFID tags here-to-fore commercially available, an RFID or sensor tag of the present developmental type includes one-port surface-acoustic-wave (SAW) devices. In simplified terms, the mode of operation of a basic one-port SAW device as used heretofore in an RFID device is the following: An interrogating radio signal is converted, at an input end, from

  18. Monoculture of leafcutter ant gardens.

    Directory of Open Access Journals (Sweden)

    Ulrich G Mueller

    Full Text Available BACKGROUND: Leafcutter ants depend on the cultivation of symbiotic Attamyces fungi for food, which are thought to be grown by the ants in single-strain, clonal monoculture throughout the hundreds to thousands of gardens within a leafcutter nest. Monoculture eliminates cultivar-cultivar competition that would select for competitive fungal traits that are detrimental to the ants, whereas polyculture of several fungi could increase nutritional diversity and disease resistance of genetically variable gardens. METHODOLOGY/PRINCIPAL FINDINGS: Using three experimental approaches, we assessed cultivar diversity within nests of Atta leafcutter ants, which are most likely among all fungus-growing ants to cultivate distinct cultivar genotypes per nest because of the nests' enormous sizes (up to 5000 gardens and extended lifespans (10-20 years. In Atta texana and in A. cephalotes, we resampled nests over a 5-year period to test for persistence of resident cultivar genotypes within each nest, and we tested for genetic differences between fungi from different nest sectors accessed through excavation. In A. texana, we also determined the number of Attamyces cells carried as a starter inoculum by a dispersing queens (minimally several thousand Attamyces cells, and we tested for genetic differences between Attamyces carried by sister queens dispersing from the same nest. Except for mutational variation arising during clonal Attamyces propagation, DNA fingerprinting revealed no evidence for fungal polyculture and no genotype turnover during the 5-year surveys. CONCLUSIONS/SIGNIFICANCE: Atta leafcutter ants can achieve stable, fungal monoculture over many years. Mutational variation emerging within an Attamyces monoculture could provide genetic diversity for symbiont choice (gardening biases of the ants favoring specific mutational variants, an analog of artificial selection.

  19. Low variation in ribosomal DNA and internal transcribed spacers of the symbiotic fungi of leaf-cutting ants (Attini: Formicidae

    Directory of Open Access Journals (Sweden)

    Silva-Pinhati A.C.O.

    2004-01-01

    Full Text Available Leaf-cutting ants of the genera Atta and Acromyrmex (tribe Attini are symbiotic with basidiomycete fungi of the genus Leucoagaricus (tribe Leucocoprineae, which they cultivate on vegetable matter inside their nests. We determined the variation of the 28S, 18S, and 5.8S ribosomal DNA (rDNA gene loci and the rapidly evolving internal transcribed spacers 1 and 2 (ITS1 and ITS2 of 15 sympatric and allopatric fungi associated with colonies of 11 species of leafcutter ants living up to 2,600 km apart in Brazil. We found that the fungal rDNA and ITS sequences from different species of ants were identical (or nearly identical to each other, whereas 10 GenBank Leucoagaricus species showed higher ITS variation. Our findings suggest that Atta and Acromyrmex leafcutters living in geographic sites that are very distant from each other cultivate a single fungal species made up of closely related lineages of Leucoagaricus gongylophorus. We discuss the strikingly high similarity in the ITS1 and ITS2 regions of the Atta and Acromyrmex symbiotic L. gongylophorus studied by us, in contrast to the lower similarity displayed by their non-symbiotic counterparts. We suggest that the similarity of our L. gongylophorus isolates is an indication of the recent association of the fungus with these ants, and propose that both the intense lateral transmission of fungal material within leafcutter nests and the selection of more adapted fungal strains are involved in the homogenization of the symbiotic fungal stock.

  20. Sequence-Dependence of the Energetics of Opening of AT Basepairs in DNA

    OpenAIRE

    Chen, Congju; Russu, Irina M.

    2004-01-01

    Proton exchange and nuclear magnetic resonance spectroscopy are being used to characterize the energetics of opening of AT/TA basepairs in the DNA dodecamer 5′-d(GCTATAAAAGGG)-3′/5′-d(CCCTTTTATAGC)-3′. The dodecamer contains the TATA box of the adenovirus major late promoter. The equilibrium constants for opening of each basepair are measured from the dependence of the exchange rates of imino protons on ammonia concentration. The enthalpy, entropy, and free energy changes in the opening react...

  1. Cartography past, present and future

    CERN Document Server

    Rhind, DW

    2013-01-01

    Making maps dates back at least four thousand years and it is widely recognised that many maps are of great historical value and present a skilled method of summarising the real world on a sheet of paper. Less well known is the judgement involved in the selection and simplification of features, the complex transformation of space and the exacting standards which are needed in cartography. This book is primarily a tribute to Professor F.J. Ormeling, former President and Secretary/Treasurer of the ICA and gives a wide ranging review of the current status of cartography, how this status was atta

  2. Radiometric 81Kr dating identifies 120,000-year-old ice at Taylor Glacier, Antarctica

    OpenAIRE

    Buizert, Christo; Baggenstos, Daniel; Jiang, Wei; Purtschert, Roland; Petrenko, Vasilii V.; Lu, Zheng-Tian; Müller, Peter; Kuhl, Tanner; Lee, James,; Severinghaus, Jeffrey P.; Brook, Edward J.

    2014-01-01

    We present the first successful 81Kr-Kr radiometric dating of ancient polar ice. Krypton was extracted from the air bubbles in four ~350 kg polar ice samples from Taylor Glacier in the McMurdo Dry Valleys, Antarctica, and dated using Atom Trap Trace Analysis (ATTA). The 81Kr radiometric ages agree with independent age estimates obtained from stratigraphic dating techniques with a mean absolute age offset of 6 +/- 2.5 ka. Our experimental methods and sampling strategy are validated by 1) 85Kr ...

  3. Extended Range Passive Wireless Tag System and Method

    Science.gov (United States)

    Fink, Patrick W. (Inventor); Kennedy, Timothy F. (Inventor); Lin, Gregory Y. (Inventor)

    2013-01-01

    A passive wireless tag assembly comprises a plurality of antennas and transmission lines interconnected with circuitry and constructed and arranged in a Van Atta array or configuration to reflect an interrogator signal in the direction from where it came. The circuitry may comprise at least one surface acoustic wave (SAW)-based circuit that functions as a signal reflector and is operatively connected with an information circuit. In another embodiment, at least one delay circuit and/or at least one passive modulation circuit(s) are utilized. In yet another embodiment, antennas connected to SAW-based devices are mounted to at least one of the orthogonal surfaces of a corner reflector.

  4. PRIMER REPORTE DE LA FAMILIA CHEIRIDIIDAE (ARACHNIDA: PSEUDOSCORPIONIDA EN COLOMBIA

    Directory of Open Access Journals (Sweden)

    Jorge Alexander QUIRÓS-RODRÍGUEZ

    2015-01-01

    Full Text Available Durante un estudio de la fauna de artrópodos asociada a montículos de detritos de hormigas de la especie Atta colombica Guérin- Méneville, 1844 (Hymenoptera: Formicidae en la hacienda Santa Isabel, corregimiento de Patio Bonito, Córdoba, se encontraron representantes de la familia Cheiridiidae. Por tanto, estos pseudoescorpiones se convierten en el primer reporte de la familia para Colombia y por primera vez se registra su presencia en detritus de hormigas. Así mismo, este reporte, amplía su distribución conocida para Suramérica.

  5. Hongos asociados con dos poblaciones de Acromyrmex lobicornis (Formicidae) de San Luis, Argentina

    OpenAIRE

    Lugo, Mónica Alejandra; Crespo, Esteban María; Cafaro, Matias Jose; Jofre, Laura Elizabeth

    2015-01-01

    Fungi associated with two populations of Acromyrmex lobicornis (Formicidae) from San Luis, Argentina. The ant genera Atta and Acromyrmex (Tribe Attini) include the mowers or trimmers of leaves called leaf-cutting ants, which are the only ants that show an obligate dependence of fungal symbionts as a food source. Fragments of plants collected by these ants are used to grow the fungal symbionts, which produce gongylidia for the larvae and queen of the colony to feed on. The aim of this study wa...

  6. Synthesis of the Enantiomers of Tedanalactam and the First Total Synthesis and Configurational Assignment of (+)-Piplaroxide.

    Science.gov (United States)

    Romero-Ibañez, Julio; Xochicale-Santana, Leonardo; Quintero, Leticia; Fuentes, Lilia; Sartillo-Piscil, Fernando

    2016-04-22

    Highlighting the recently established methodology for the direct synthesis of glycidic amides from tertiary allyl amines, the synthesis of the enantiomers of tedanalactam were completed in two steps from the corresponding chiral dihydropiperidine. Additionally, the (+)- and (-)-enantiomers of piplaroxide were obtained from their respective tedanalactam precursor, and the absolute configuration of the naturally occurring (+)-piplaroxide was determined. The present approach represents not only the shortest synthesis of (-)-tedanalactam but also the first total synthesis of (+)-piplaroxide, a repellent against the leafcutter ant Atta cephalotes.

  7. Comportamento e dieta alimentar de uma espécie de Latrodectus do grupo Mactans (Araneae, Theridiidae em cativeiro Behavior and diet supply of Latrodectus group Mactans (Araneae, Theridiidae in captivity

    Directory of Open Access Journals (Sweden)

    Maria de Fátima da Rocha Dias

    1999-01-01

    Full Text Available Latrodectus gr. mactans is responsible for 28% of ali accidents provoked by spiders in state of Bahia, Brazil (1980-1990, which makes necessary the study of its manejament. The spiders were captured in Ondina, Salvador, and in Baxio, Esplanada (Bahia, Brazil; they were mantained in captivity, with food supply weekly (Atta sp., larva of Tenebrio sp. and Drosophila melanogaster with three hours/ offers observation time, during march/95 to april/96. In captivity, the spiders accepted two kinds of food: Atta sp., which seems to be the major item of its diet in natural conditions, and larva of Tenebrio sp., which is not available in natural conditions. Drosophila melanogaster was systematically rejected. The feeding behavior iscomposed by four distinct steps: (1 imrnobilization, (2 inoculation, (3 second immobilization and (4 ingestion. Two kinds of social alimentary behavior are descri-bed. The results indicated that larvae of Tenebrio sp. can be an alternative supply for successfull maintenance of this specie in captivity.

  8. Radiometric 81Kr dating identifies 120,000-year-old ice at Taylor Glacier, Antarctica.

    Science.gov (United States)

    Buizert, Christo; Baggenstos, Daniel; Jiang, Wei; Purtschert, Roland; Petrenko, Vasilii V; Lu, Zheng-Tian; Müller, Peter; Kuhl, Tanner; Lee, James; Severinghaus, Jeffrey P; Brook, Edward J

    2014-05-13

    We present successful (81)Kr-Kr radiometric dating of ancient polar ice. Krypton was extracted from the air bubbles in four ∼350-kg polar ice samples from Taylor Glacier in the McMurdo Dry Valleys, Antarctica, and dated using Atom Trap Trace Analysis (ATTA). The (81)Kr radiometric ages agree with independent age estimates obtained from stratigraphic dating techniques with a mean absolute age offset of 6 ± 2.5 ka. Our experimental methods and sampling strategy are validated by (i) (85)Kr and (39)Ar analyses that show the samples to be free of modern air contamination and (ii) air content measurements that show the ice did not experience gas loss. We estimate the error in the (81)Kr ages due to past geomagnetic variability to be below 3 ka. We show that ice from the previous interglacial period (Marine Isotope Stage 5e, 130-115 ka before present) can be found in abundance near the surface of Taylor Glacier. Our study paves the way for reliable radiometric dating of ancient ice in blue ice areas and margin sites where large samples are available, greatly enhancing their scientific value as archives of old ice and meteorites. At present, ATTA (81)Kr analysis requires a 40-80-kg ice sample; as sample requirements continue to decrease, (81)Kr dating of ice cores is a future possibility.

  9. Haplotype of gene Nedd4 binding protein 2 associated with sporadic nasopharyngeal carcinoma in the Southern Chinese population

    Directory of Open Access Journals (Sweden)

    Feng Qi-Sheng

    2007-07-01

    Full Text Available Abstract Background Bcl-3 as an oncoprotein is overexpressed in nasopharyngeal carcinoma (NPC. Nedd4 binding protein 2 (N4BP2, which is located in the NPC susceptibility locus, is a Bcl-3 binding protein. This study is aimed to explore the association between N4BP2 genetic polymorphism and the risk of NPC. Methods We performed a hospital-based case-control study, including 531 sporadic NPC and 480 cancer-free control subjects from southern China. PCR-sequencing was carried out on Exons, promoter region and nearby introns of the N4BP2 gene. The expression pattern of N4BP2 and Bcl-3 was also analyzed. Results We observed a statistically significant difference in haplotype blocks ATTA and GTTG between cases and controls. In addition, three novel SNPs were identified, two of which were in exons (loc123-e3l-snp2, position 39868005, A/G, Met171Val; RS17511668-SNP2, position 39926432, G/A, Glu118Lys, and one was in the intron6 (RS794001-SNP1, position 39944127, T/G. Moreover, N4BP2 was at higher levels in a majority of tumor tissues examined, relative to paired normal tissues. Conclusion These data suggest that haplotype blocks ATTA and GTTG of N4BP2 is correlation with the risk of sporadic nasopharyngeal carcinoma in the Southern Chinese population and N4BP2 has a potential role in the development of NPC.

  10. Development of Myrmeleon brasiliensis (Navas) (Neuroptera, Myrmeleontidae), in laboratory, with different natural diets

    Energy Technology Data Exchange (ETDEWEB)

    Missirian, Giani L.B. [Centro Universitario da Grande Dourados, MS (Brazil). Curso de Ciencias Biologicas; Uchoa-Fernandes, Manoel A. [Universidade Federal da Grande Dourados, MS (Brazil). Faculdade de Ciencias Biologicas e Ambientais]. E-mail: uchoa.fernandes@ufgd.edu.br; Fischer, Erich [Universidade Federal de Mato Grosso do Sul, Campo Grande, MS (Brazil). Dept. de Biologia

    2006-07-01

    Antlions larvae are sit-and-wait predators that capture arthropod prey in conical sand pits. The aim of this paper were to determine the effect of different natural diets [leaf-cutting ants (Atta spp.), fruit fly larvae (Anastrepha spp. and Ceratitis capitata) and mixed diet (Atta spp. plus fruit fly larvae)] on the development of larvae and pupae of M. brasiliensis (Navas, 1914) and to estimate the number and size of prey caught in each instar and on each kind of diet. The average duration (days) of the second and third instars of M. brasiliensis was longer when larvae of antlion were fed with leaf-cutting ants. The diets did not affect the duration of the pupal stage nor the pupae size. The different diets did not affect the mean width of head capsule (mm), the mean weight (mg) or the mean body size (mm) in the different instars of M. brasiliensis. In the second and third instars, the larvae of M. brasiliensis fed with leaf-cutting ants consumed more prey than larvae kept on other diets. Adults whose larvae were fed fruit fly larvae were larger than adults on other diets. Although Myrmeleontidae are few studied in Brazil, these results contribute to knowledge of M. brasiliensis biology, but also suggest the need of studies about the development of larvae and pupae in natural environments. (author)

  11. PRIMER REPORTE DE LA FAMILIA CHEIRIDIIDAE (ARACHNIDA: PSEUDOSCORPIONIDA EN COLOMBIA

    Directory of Open Access Journals (Sweden)

    Jorge Alexander QUIROZ-RODRÍGUEZ

    2015-07-01

    Full Text Available Durante un estudio de la fauna de artrópodos asociada a montículos de detritos de hormigas de la especie Atta colombica Guérin-Méneville, 1844 (Hymenoptera: Formicidae en la hacienda Santa Isabel, corregimiento de Patio Bonito en el departamento de Córdoba, se encontraron representantes de la familia Cheiridiidae. Por tanto, estos pseudoescorpiones se convierten en el primer reporte de la familia para Colombia y por primera vez se registra su presencia en detritus de hormigas. Así mismo, este reporte, amplía su distribución conocida para Suramérica.First Report of Family Cheiridiidae (Arachnida: Pseudoscorpionida in ColombiaDuring a study of the arthropod fauna associated with mounds of detritus produced by Atta colombica (Hymenoptera: Formicidae in the Santa Isabel estate, locality of Patio Bonito, Department of Córdoba, were found representatives of the family Cheiridiidae. Therefore, these pseudoscorpions becomes in the first report of the family to Colombia and for the first time is recorded its presence in ant detritus. Also, this report extends its known distribution range in South America.   

  12. Prevalence of the genus Cladosporium on the integument of leaf-cutting ants characterized by 454 pyrosequencing.

    Science.gov (United States)

    Duarte, A P M; Ferro, M; Rodrigues, A; Bacci, M; Nagamoto, N S; Forti, L C; Pagnocca, F C

    2016-09-01

    The relationship of attine ants with their mutualistic fungus and other microorganisms has been studied during the last two centuries. However, previous studies about the diversity of fungi in the ants' microenvironment are based mostly on culture-dependent approaches, lacking a broad characterization of the fungal ant-associated community. Here, we analysed the fungal diversity found on the integument of Atta capiguara and Atta laevigata alate ants using 454 pyrosequencing. We obtained 35,453 ITS reads grouped into 99 molecular operational taxonomic units (MOTUs). Data analysis revealed that A. capiguara drones had the highest diversity of MOTUs. Besides the occurrence of several uncultured fungi, the mycobiota analysis revealed that the most abundant taxa were the Cladosporium-complex, Cryptococcus laurentii and Epicoccum sp. Taxa in the genus Cladosporium were predominant in all samples, comprising 67.9 % of all reads. The remarkable presence of the genus Cladosporium on the integument of leaf-cutting ants alates from distinct ant species suggests that this fungus is favored in this microenvironment.

  13. Metagenomic and metaproteomic insights into bacterial communities in leaf-cutter ant fungus gardens.

    Science.gov (United States)

    Aylward, Frank O; Burnum, Kristin E; Scott, Jarrod J; Suen, Garret; Tringe, Susannah G; Adams, Sandra M; Barry, Kerrie W; Nicora, Carrie D; Piehowski, Paul D; Purvine, Samuel O; Starrett, Gabriel J; Goodwin, Lynne A; Smith, Richard D; Lipton, Mary S; Currie, Cameron R

    2012-09-01

    Herbivores gain access to nutrients stored in plant biomass largely by harnessing the metabolic activities of microbes. Leaf-cutter ants of the genus Atta are a hallmark example; these dominant neotropical herbivores cultivate symbiotic fungus gardens on large quantities of fresh plant forage. As the external digestive system of the ants, fungus gardens facilitate the production and sustenance of millions of workers. Using metagenomic and metaproteomic techniques, we characterize the bacterial diversity and physiological potential of fungus gardens from two species of Atta. Our analysis of over 1.2 Gbp of community metagenomic sequence and three 16S pyrotag libraries reveals that in addition to harboring the dominant fungal crop, these ecosystems contain abundant populations of Enterobacteriaceae, including the genera Enterobacter, Pantoea, Klebsiella, Citrobacter and Escherichia. We show that these bacterial communities possess genes associated with lignocellulose degradation and diverse biosynthetic pathways, suggesting that they play a role in nutrient cycling by converting the nitrogen-poor forage of the ants into B-vitamins, amino acids and other cellular components. Our metaproteomic analysis confirms that bacterial glycosyl hydrolases and proteins with putative biosynthetic functions are produced in both field-collected and laboratory-reared colonies. These results are consistent with the hypothesis that fungus gardens are specialized fungus-bacteria communities that convert plant material into energy for their ant hosts. Together with recent investigations into the microbial symbionts of vertebrates, our work underscores the importance of microbial communities in the ecology and evolution of herbivorous metazoans.

  14. Laboratory for Radiokrypton Dating

    Science.gov (United States)

    Lu, Z.; Bailey, K.; Jiang, W.; Müller, P.; O'Connor, T. P.; Zappala, J. C.

    2013-12-01

    Due to its simple production and transport processes in the terrestrial environment, the long-lived noble-gas isotope 81Kr (half-life = 230 kyr) is the ideal tracer for studying old water and ice in the age range of 10^5-10^6 years, a range beyond the reach of 14C. 81Kr dating, a concept pursued in the past four decades by numerous laboratories employing a variety of techniques, is now available for the first time to the earth science community at large. This is made possible by the development of ATTA-3 (Jiang et al., GCA 91, 1-6; 2012), an efficient and selective atom counter based on the Atom Trap Trace Analysis method (Chen et al., Science 286, 1139-1141; 1999). The instrument is capable of measuring both 81Kr/Kr and 85Kr/Kr ratios of environmental samples in the range of 10^-14-10^-10. For 81Kr-dating in the age range of 150 - 1,500 kyr, the required sample size is 5 - 10 micro-L STP of krypton gas, which can be extracted from approximately 100 - 200 kg of water or 40 - 80 kg of ice. For 85Kr/Kr analysis, the required sample size is generally smaller by an order of magnitude because of the isotope's higher initial abundance in the atmosphere. The Laboratory for Radiokrypton Dating is currently equipped to analyze up to 120 samples per year. With future equipment upgrades, this limit can be increased as demand grows. In the period since November 2011, the Laboratory has measured both 81Kr/Kr and 85Kr/Kr ratios in over 50 samples that had been extracted by collaborators from six different continents. The samples were from groundwater wells in the Great Artesian Basin (Australia), Guarani Aquifer (Brazil), and Locust Grove (Maryland); from brine wells of the Waste Isolation Pilot Plant (New Mexico); from geothermal steam vents in Yellowstone National Park; from near-surface ice at Taylor Glacier, Antarctica; and from deep mines in South Africa. Sample collection and purification was performed by groups including the University of Illinois at Chicago, University

  15. Tracing Noble Gas Radionuclides in the Environment

    CERN Document Server

    Collon, P; Lu, Z T

    2004-01-01

    Trace analysis of radionuclides is an essential and versatile tool in modern science and technology. Due to their ideal geophysical and geochemical properties, long-lived noble gas radionuclides, in particular, 39Ar (t1/2 = 269 yr), 81Kr (t1/2 = 2.3x10^5 yr) and 85Kr (t1/2 = 10.8 yr), have long been recognized to have a wide range of important applications in Earth sciences. In recent years, significant progress has been made in the development of practical analytical methods, and has led to applications of these isotopes in the hydrosphere (tracing the flow of groundwater and ocean water). In this article, we introduce the applications of these isotopes and review three leading analytical methods: Low-Level Counting (LLC), Accelerator Mass Spectrometry (AMS) and Atom Trap Trace Analysis (ATTA).

  16. Raise your defence: a baseline for security

    CERN Multimedia

    Computer Security Team

    2011-01-01

    It is an unfair imbalance: the (computer) security of a system/service is only as strong as the weakest link in the chain of protection. This provides attackers with an incredible advantage: they can choose when to attack, where and with which means. The defence side is permanently under pressure: they must defend at all times all assets against all eventualities. For computer security, this means that every computer system, every account, every web site and every service must be properly protected --- always.   In particular, at CERN, those services visible to the Internet are permanently probed. Web sites and servers are permanently scanned by adversaries for vulnerabilities; attackers repeatedly try to guess user passwords on our remote access gateways like LXPLUS or CERNTS; computing services, e.g. for Grid computing, are analysed again and again by malicious attackers for weaknesses which can be exploited. Thanks to the vigilance of the corresponding system and service experts, these atta...

  17. [Alkaloids of Vinca rosea L. introduced to Western Georgia].

    Science.gov (United States)

    Vachnadze, N S; Kintsurashvili, L G; Suladze, T Sh; Bakuridze, A D; Vachnadze, V Iu

    2013-11-01

    Vinca roseae L. (Саtharanthus rosea (L.) G. Don) was introduced at Kobuleti experimental station of medical plants. The object of investigation was the plant material of Vinca roseae L. collected in May, 2005., September, 2006 and October, 2009. Total alkaloids were obtained in accordance with Atta- ur-Rachman method. The variability of the quantitative and qualitative composition of total alkaloids and vincaleikoblastin (VLB) fraction during vegetation was studied. It was established that the maximal content of total alkaloids and VLB fraction of Vinca roseae L. is accumulated in the phase of secondary flowering, hence the collecting of a plant material is recommended to be made during the aforesaid vegetation phase as for this period it is a rather high output of a raw material, alkaloid complex and VLB faction. Alkaloids vinkaleikoblastin, ajmalicine and new epimer tetrahydroalstonine with С3Н-α- orientation were yielded, separated and identified using modern physical-chemical and spectral methods (13С NMR).

  18. Co-evolution of enzyme function in the attine ant-fungus symbiosis

    DEFF Research Database (Denmark)

    de Fine Licht, Henrik Hjarvard; Schiøtt, Morten; Boomsma, Jacobus Jan

    Introduction: Fungus-growing ants cultivate specialized fungi in the tribe Leucocoprineae (Lepiotaceae: Basidiomycota) inside their nests. The conspicuous leaf-cutting ants in the genus Atta build huge nests displacing several cubic meters of soil, whereas lower attine genera such as Cyphomyrmex...... have small nests with a fungus garden the size of a table-tennis ball. Only the leaf-cutting ants are specialized on using fresh leaves as substrate for their fungus gardens, whereas the more basal attine genera use substrates such as dry plant material (leaf litter and small twigs) and also insect...... feces and insect carcasses. This diverse array of fungal substrates across the attine lineage implies that the symbiotic fungus needs different enzymes to break down the plant material that the ants provide or different efficiencies of enzyme function. Methods: (1.) We made a literature survey...

  19. Influence of stable stratification on three-dimensional isotropic turbulence

    Science.gov (United States)

    Metais, O.

    The influence of a stable stratification on three-dimensional homogeneous turbulence is investigated by performing large eddy simulations with the subgrid scales procedure developed by Chollet and Lesieur for isotropic turbulence. Computational initial conditions close to those of the experiments performed by Itsweire, Helland and Van Atta allow the comparison of the experimental and numerical evolutions of density-stratified turbulent flows. Theoretical works by Riley, Metcalfe and Weisman and by Lilly suggest that low Froude number stably-stratified turbulence may be a nearly noninteracting superposition of wave and quasi-horizontal turbulent vortex motions. For our computations the stably-stratified turbulence seems to be a decaying three-dimensional turbulence pulsed by internal gravity waves. However some tendencies towards two-dimensional turbulence are observed.

  20. Real & Financial Sectors, ``koq Financenaann..'' & Elbio Dagotto's Interactions

    Science.gov (United States)

    Maksoed, Wh-

    2016-10-01

    In conjunctions between PMRI/Pendidikan Matematika Realistik Indonesia fom Dr. RK Sembiring to ``ASTRANOMICS'': the New Reality in Business Aviation herewith provided `interaction between real & financial sector' and financialisation from Heinrich Bortis: ``the Real & Financial Sector of a Monetary Production Economy in the perspective of classical-Keynesian political economy'' ever specifies ``sector Riil'' from HE. Mr. Ir. Aburizal Bakrie. Instead describes the context of CMR/Colossal Magnetoresistance cq Carlos SLIM, the richest entrepreneur in the world 2014 also obtaines Dagotto & Tokura: ``Strongly correlated Electronic Materials: Present & Future'',MRS Bulletin, Nov, 2008. Ever existed of UN Secretary General Kofie Atta Annan, for Lih-AT TA-ruh di mana?'' are ```koq Financenaann..?'' in-between conjunctions. CMR are other notions of GiantMagnetoresistance from Fert & Grundberg who awarded with Nobel Prize in Physics, 2007. Heartfelt Gratitudes to HE. Mr. Prof. Ir. HANDOJO.

  1. The conversion of SO{sub 2} to SO{sub 3} in gas turbine engines

    Energy Technology Data Exchange (ETDEWEB)

    Miake-Lye, R.C.; Anderson, M.R.; Brown, R.C.; Kolb, C.E. [Aerodyne Research, Inc., Billerica, MA (United States). Center for Chemical and Environmental Physics; Sorokin, A.A.; Buriko, Y.I. [Scientific Research Center `Ecolen`, Moscow (Russian Federation)

    1997-12-31

    The oxidation of fuel sulfur to S(6) (SO{sub 3}+H{sub 2}SO{sub 4}) in a supersonic (Concorde) and a subsonic (ATTAS) aircraft engine is estimated numerically. The results indicate between 2% and 10% of the fuel sulfur is emitted as S(6). It is also shown that conversion in the turbine is limited by the level of atomic oxygen at the combustor exit, resulting in a higher oxidation efficiency as the sulfur mass loading is decreased. SO{sub 2} and SO{sub 3} are the primary sulfur oxidation products, with less than 1% of fuel sulfur converted to H{sub 2}SO{sub 4}. For the Concorde, H{sub 2}SO{sub 4} was primarily formed during the supersonic expansion through the divergent nozzle. (author) 20 refs.

  2. Development of Myrmeleon brasiliensis (Navás (Neuroptera, Myrmeleontidae, in laboratory, with different natural diets Desenvolvimento de Myrmeleon brasiliensis (Navás (Neuroptera, Myrmeleontidae, em laboratório, com diferentes dietas naturais

    Directory of Open Access Journals (Sweden)

    Giani L. B. Missirian

    2006-12-01

    Full Text Available Antlions larvae are sit-and-wait predators that capture arthropod prey in conical sand pits. The aim of this paper were to determine the effect of different natural diets [leaf-cutting ants (Atta spp., fruit fly larvae (Anastrepha spp. and Ceratitis capitata and mixed diet (Atta spp. plus fruit fly larvae] on the development of larvae and pupae of M. brasiliensis (Navás, 1914 and to estimate the number and size of prey caught in each instar and on each kind of diet. The average duration (days of the second and third instars of M. brasiliensis was longer when larvae of antlion were fed with leaf-cutting ants. The diets did not affect the duration of the pupal stage nor the pupae size. The different diets did not affect the mean width of head capsule (mm, the mean weight (mg or the mean body size (mm in the different instars of M. brasiliensis. In the second and third instars, the larvae of M. brasiliensis fed with leaf-cutting ants consumed more prey than larvae kept on other diets. Adults whose larvae were fed fruit fly larvae were larger than adults on other diets. Although Myrmeleontidae are few studied in Brazil, these results contribute to knowledge of M. brasiliensis biology, but also suggest the need of studies about the development of larvae and pupae in natural environments.Larvas de formiga-leão são conhecidas por suas armadilhas ("funis" que constroem em solo arenoso, sob as quais esperam por suas presas. Este trabalho teve como objetivos verificar o efeito de diferentes dietas naturais [formigas-cortadeiras (Atta spp., larvas de moscas-das-frutas (Anastrepha spp. e Ceratitis capitata e dieta mista (Atta spp. e larvas de moscas-das-frutas] sobre o desenvolvimento larval e pupal de M. brasiliensis (Navás, 1914 e estimar o número e tamanho de presas capturadas, por instar larval, em cada dieta. No segundo e terceiro instares, as larvas de M. brasiliensis alimentadas com formigas-cortadeiras consumiram um número maior de presas e a

  3. Uninformed sacrifice: Evidence against long-range alarm transmission in foraging ants exposed to localized abduction

    Science.gov (United States)

    Tejera, F.; Reyes, A.; Altshuler, E.

    2016-07-01

    It is well established that danger information can be transmitted by ants through relatively small distances, provoking either a state of alarm when they move away from potentially dangerous stimulus, or charge toward it aggressively. There is almost no knowledge if danger information can be transmitted along large distances. In this paper, we abduct leaf cutting ants of the species Atta insularis while they forage in their natural environment at a certain point of the foraging line, so ants make a "U" turn to escape from the danger zone and go back to the nest. Our results strongly suggest that those ants do not transmit "danger information" to other nestmates marching towards the abduction area. The individualistic behavior of the ants returning from the danger zone results in a depression of the foraging activity due to the systematic sacrifice of non-informed individuals.

  4. Analysis of SSR in Citrus Sequences from EMBL Database

    Institute of Scientific and Technical Information of China (English)

    MENG Hai-jun; CAO Qing-qin; HU Zhi-yong; LIU Gao-ping; CHENG Yun-jiang; DENG Xiu-xin

    2005-01-01

    Abundance of simple sequence repeat (SSR) in Citrus sequences from EMBL database was investigated by using computer program MISA (MIcroSAtellite), which aimed to provide useful information for the development of SSR markers.Among 32 896 sequences of Citrus, 4987 SSRs were found in 4167 sequences and the average distance between SSRs was approximately 3.5 kb. Mononucleotide repeats (50.6%) were the most abundant repeats. And di-, tri-, tetra-, penta- and hexa-nucleotide repeats were 22.8, 25.2, 1, 0.08, and 0.36%, respectively. The most abundant motif was A/T followed in descending order by AG/CT, AC/GT, AT/TA. AAT/ATT, AAG/CTT, AGC/CGT, ACG/CTG and C/G. They comprised about90% of all microsatellites. Ten primer pairs were designed, and three of them produced clear visible bands among Citrus and its related genera.

  5. Insetos em presépios e as "formigas vestidas" de Jules Martin (1832-1906: uma curiosa manufatura paulistana do final do século XIX

    Directory of Open Access Journals (Sweden)

    Dante Martins Teixeira

    2008-01-01

    Full Text Available Present in Brazil since the beginning of Portuguese colonization, crèche nativity scenes were soon adapted to local reality, a propitious circumstance for the appearance of heterodox conceptions and the use of exotic elements of the fauna and flora peculiar to each region. As records about insects are very uncommon, it is noteworthy that females of leaf-cutting ants, Atta sp. (Hymenoptera, Formicidae, were used to compose crèche nativity scenes in São Paulo State. Having subsisted at least up to the decade of 1960, the "ant crèches" of cities such as Embu das Artes could be related to the then famous "dressed ants" created by Jules Martin, a curious manufacture of the city of São Paulo in the last quarter of the 19th century.

  6. Emission of ions and charged soot particles by aircraft engines

    Directory of Open Access Journals (Sweden)

    A. Sorokin

    2002-11-01

    Full Text Available In this article, a model which examines the formation and evolution of chemiions in an aircraft engine is proposed. This model which includes chemiionisation, electron thermo-emission, electron attachment to soot particles and to neutral molecules, electron-ion and ion-ion recombination, ion-soot interaction, allows the determination of the ion concentration at the exit of the combustor and at the nozzle exit of the engine. It also allows the determination of the charge of the soot particles. A comparison of the model results with the available ground-based experimental data obtained on the ATTAS research aircraft engines during the SULFUR experiments (Schumann, 2002 shows an excellent agreement.

  7. The Evolutionary Innovation of Nutritional Symbioses in Leaf-Cutter Ants

    Directory of Open Access Journals (Sweden)

    Frank O. Aylward

    2012-01-01

    Full Text Available Fungus-growing ants gain access to nutrients stored in plant biomass through their association with a mutualistic fungus they grow for food. This 50 million-year-old obligate mutualism likely facilitated some of these species becoming dominant Neotropical herbivores that can achieve immense colony sizes. Recent culture-independent investigations have shed light on the conversion of plant biomass into nutrients within ant fungus gardens, revealing that this process involves both the fungal cultivar and a symbiotic community of bacteria including Enterobacter, Klebsiella, and Pantoea species. Moreover, the genome sequences of the leaf-cutter ants Atta cephalotes and Acromyrmex echinatior have provided key insights into how this symbiosis has shaped the evolution of these ants at a genetic level. Here we summarize the findings of recent research on the microbial community dynamics within fungus-growing ant fungus gardens and discuss their implications for this ancient symbiosis.

  8. An Atom Trap Trace Analysis System for Measuring Krypton Contamination in Xenon Dark Matter Detectors

    CERN Document Server

    Aprile, Elena; Loose, Andre; Goetzke, Luke W; Zelevinsky, Tanya

    2013-01-01

    We have developed an atom trap trace analysis (ATTA) system to measure Kr in Xe at the part per trillion (ppt) level, a prerequisite for the sensitivity achievable with liquid xenon dark matter detectors beyond the current generation. Since Ar and Kr have similar laser cooling wavelengths, the apparatus has been tested with Ar to avoid contamination prior to measuring Xe samples. A radio-frequency (RF) plasma discharge generates a beam of metastable Ar which is optically collimated, slowed, and trapped using standard magneto-optical techniques. We detect the fluorescence of single trapped $^{40}$Ar atoms with a signal to noise ratio of 5. The measured system efficiency of $3 \\times 10^{-9}$ for Ar corresponds to an expected Kr in Xe sensitivity at the ppt level.

  9. A quality management system for chemical processes; Qualita' dei processi chimici

    Energy Technology Data Exchange (ETDEWEB)

    Tantalo, P. [Tecnopolis Casata Novus Ortus s.c.r.l., Bari (Italy). Servizi Informativi

    2000-06-01

    The requirements of the international quality assurance standards are briefly discussed in connection with the safety and the environment protection needs of chemical industry. The paper summarizes some general techniques useful for the analyses and describes a managing system to improve the commercial quality of products, the safety at work and the environmental quality of chemical processes. [Italian] Vengono brevemente discussi i requisiti delle norme Iso 9000 sui Sistemi di Assicurazione della Qualita' relativamente al contesto dell'industria chimica e con particolare riferimento ai problemi di sicurezza e compatibilita' ambientale degli impianti produttivi e dei prodotti. A tale scopo, sono riassunte alcune fondamentali tecniche di analisi dell'affidabilita' e sicurezza dei sistemi tecnici ed e' presentata una filosofia generale di gestione atta a migliorare contemporaneamente sia la qualita' commerciale dei prodotti, sia la qualita' ambientale e la sicurezza dei processi.

  10. Variation in fungal enzyme spectra may affect mutualistic division of labour between ants and fungus gardens

    DEFF Research Database (Denmark)

    de Fine Licht, Henrik Hjarvard; Boomsma, Jacobus Jan

    range, and a paraphyletic assembly of Trachymyrmex and Sericomyrmex species that cultivate more genetically diverse fungal symbionts. Leaf-decomposition productivity of colonies depends on the combined efforts of ant foragers collecting and macerating plant material and fungal enzymes excreted directly...... partners vary in metabolic performance, division of labour may not always be optimized and co-evolutionary trajectories become less predictable. The higher fungus-growing (attine) ants consist of the leafcutter ants (Acromyrmex and Atta), which rear a single fungal species throughout their Latin American...... or indirectly via ant fecal fluid. We determined the interaction specificity between ant species and fungal strains across sympatric populations of six Trachymyrmex and Sericomyrmex species in Panama, and established that these ants jointly reared eight fungal haplotype groups that differed significantly...

  11. On the topologic structure of economic complex networks: Empirical evidence from large scale payment network of Estonia

    CERN Document Server

    de la Torre, Stephanie Rendón; Kitt, Robert; Engelbrecht, Jüri

    2016-01-01

    This paper presents the first topological analysis of the economic structure of an entire country based on payments data obtained from Swedbank. This data set is exclusive in its kind because around 80% of Estonia's bank transactions are done through Swedbank, hence, the economic structure of the country can be reconstructed. Scale-free networks are commonly observed in a wide array of different contexts such as nature and society. In this paper, the nodes are comprised by customers of the bank (legal entities) and the links are established by payments between these nodes. We study the scaling-free and structural properties of this network. We also describe its topology, components and behaviors. We show that this network shares typical structural characteristics known in other complex networks: degree distributions follow a power law, low clustering coefficient and low average shortest path length. We identify the key nodes of the network and perform simulations of resiliency against random and targeted atta...

  12. Simple cellular automata to mimic foraging ants submitted to abduction

    CERN Document Server

    Tejera, F

    2015-01-01

    Many species of ants forage by building up two files: an outbound one moving from the nest to the foraging area, and a nestbound one, returning from it to the nest. Those files are eventually submitted to different threats. If the danger is concentrated at one point of the file, one might expect that ants returning to the nest will pass danger information to their nestmates moving in the opposite direction towards the danger area. In this paper, we construct simple cellular automata models for foraging ants submitted to localized abduction, were danger information is transmitted using different protocols, including the possibility of no transmission. The parameters we have used in the simulations have been estimated from actual experiments under natural conditions. So, it would be easy to test our information-transmission hypothese in real experiments. Preliminary experimental results published elsewhere suggest that the behavior of foraging ants of the species Atta insularis is best described using the hypot...

  13. Recent developments on field gas extraction and sample preparation methods for radiokrypton dating of groundwater

    Science.gov (United States)

    Yokochi, Reika

    2016-09-01

    Current and foreseen population growths will lead to an increased demand in freshwater, large quantities of which is stored as groundwater. The ventilation age is crucial to the assessment of groundwater resources, complementing the hydrological model approach based on hydrogeological parameters. Ultra-trace radioactive isotopes of Kr (81 Kr and 85 Kr) possess the ideal physical and chemical properties for groundwater dating. The recent advent of atom trap trace analyses (ATTA) has enabled determination of ultra-trace noble gas radioisotope abundances using 5-10 μ L of pure Kr. Anticipated developments will enable ATTA to analyze radiokrypton isotope abundances at high sample throughput, which necessitates simple and efficient sample preparation techniques that are adaptable to various sample chemistries. Recent developments of field gas extraction devices and simple and rapid Kr separation method at the University of Chicago are presented herein. Two field gas extraction devices optimized for different sampling conditions were recently designed and constructed, aiming at operational simplicity and portability. A newly developed Kr purification system enriches Kr by flowing a sample gas through a moderately cooled (138 K) activated charcoal column, followed by a gentle fractionating desorption. This simple process uses a single adsorbent and separates 99% of the bulk atmospheric gases from Kr without significant loss. The subsequent two stages of gas chromatographic separation and a hot Ti sponge getter further purify the Kr-enriched gas. Abundant CH4 necessitates multiple passages through one of the gas chromatographic separation columns. The presented Kr separation system has a demonstrated capability of extracting Kr with > 90% yield and 99% purity within 75 min from 1.2 to 26.8 L STP of atmospheric air with various concentrations of CH4. The apparatuses have successfully been deployed for sampling in the field and purification of groundwater samples.

  14. Ant-fungus species combinations engineer physiological activity of fungus gardens.

    Science.gov (United States)

    Seal, J N; Schiøtt, M; Mueller, U G

    2014-07-15

    Fungus-gardening insects are among the most complex organisms because of their extensive co-evolutionary histories with obligate fungal symbionts and other microbes. Some fungus-gardening insect lineages share fungal symbionts with other members of their lineage and thus exhibit diffuse co-evolutionary relationships, while others exhibit little or no symbiont sharing, resulting in host-fungus fidelity. The mechanisms that maintain this symbiont fidelity are currently unknown. Prior work suggested that derived leaf-cutting ants in the genus Atta interact synergistically with leaf-cutter fungi (Attamyces) by exhibiting higher fungal growth rates and enzymatic activities than when growing a fungus from the sister-clade to Attamyces (so-called 'Trachymyces'), grown primarily by the non-leaf cutting Trachymyrmex ants that form, correspondingly, the sister-clade to leaf-cutting ants. To elucidate the enzymatic bases of host-fungus specialization in leaf-cutting ants, we conducted a reciprocal fungus-switch experiment between the ant Atta texana and the ant Trachymyrmex arizonensis and report measured enzymatic activities of switched and sham-switched fungus gardens to digest starch, pectin, xylan, cellulose and casein. Gardens exhibited higher amylase and pectinase activities when A. texana ants cultivated Attamyces compared with Trachymyces fungi, consistent with enzymatic specialization. In contrast, gardens showed comparable amylase and pectinase activities when T. arizonensis cultivated either fungal species. Although gardens of leaf-cutting ants are not known to be significant metabolizers of cellulose, T. arizonensis were able to maintain gardens with significant cellulase activity when growing either fungal species. In contrast to carbohydrate metabolism, protease activity was significantly higher in Attamyces than in Trachymyces, regardless of the ant host. Activity of some enzymes employed by this symbiosis therefore arises from complex interactions between the

  15. Effects of substrate, ant and fungal species on plant fiber degradation in a fungus-gardening ant symbiosis.

    Science.gov (United States)

    DeMilto, Alexandria M; Rouquette, Monte; Mueller, Ulrich G; Kellner, Katrin; Seal, Jon N

    2017-02-11

    Fungus-gardening or attine ants have outsourced most of their digestive function to a symbiotic fungus. The ants feed their fungus - essentially an external digestive organ - a variety of substrates of botanical origin, including fresh and dried flowers, leaves and insect frass (processed leaves). Although plant tissues are rich in fibers (lignocelluloses, hemicelluloses, pectins and starches) and the symbiotic fungus possesses the genetic and enzymatic machinery to metabolize these compounds, the highly derived attines, the leaf-cutters (Atta and Acromyrmex), are known to produce fiber-rich waste. While leaf-cutting ants are important consumers of primary plant tissue, there have been fewer studies on physiological activity of fungi grown by closely related ant species in the genus Trachymyrmex, which generally grow related species of fungi, have smaller colonies and consume a wider variety of fungal substrates in addition to fresh leaves and flowers. In this study, we measured the cellulase activity of the fungus-gardening ants Atta texana, Trachymyrmex arizonensis and T. septentrionalis. We then quantified fiber consumption of the fungus-gardening ants Trachymyrmex septentrionalis and Trachymyrmex arizonensis by comparing the amounts and percentages present in their food and in fungus garden refuse during a controlled feeding experiment over the span of several months. Finally, we compared waste composition of T. arizonensis colonies growing different fungal strains, because this species is known to cultivate multiple strains of Leucoagaricus in its native range. The leaf-cutting ant A. texana was found to have lower cellulytic activity than T. arizonensis or T. septentrionalis. Total lignocellulose and hemicellulose amounts were significantly lower in refuse piles than in the substrates fed to the Trachymyrmex colonies, thus these fibers were consumed by the fungal symbionts of these ant species. Although lignocellulose utilization was similar in two distinct

  16. A label-free fluorescence turn-on sensor for rapid detection of cysteine.

    Science.gov (United States)

    Chen, Xia; Liu, Hongli; Wang, Chen; Hu, Hui; Wang, Yuhui; Zhou, Xiaodong; Hu, Jiming

    2015-06-01

    A Hg(2+)-mediated fluorescence turn-on sensor for cysteine (Cys) detection was developed using the nucleic acid minor groove binding dye DAPI. In this work, two fully complementary DNA sequences, a T-rich single-stranded molecule (ssDNA) and an A-rich single-stranded molecule, were employed to constitute consecutive "AT/TA" base pairs, which could strongly enhance the fluorescence of DAPI. In the absence of cysteine, Hg(2+) reacted with T-rich single-stranded DNA and "T-Hg(2+)-T" base pairs formed, this seriously disrupted consecutive AT base pairs. As a result, the fluorescence of DAPI was not increased efficiently. However, considering that cysteine binds strongly to Hg(2+), the structure of the "T-Hg(2+)-T" complexes was destroyed in the presence of cysteine, resulting in the re-formation of consecutive AT base pairs and increased DAPI fluorescence. Obviously, the amount of cysteine could be easily measured based on the enhancement of DAPI fluorescence, and it took only 20 min to complete the whole cysteine-sensing process. Therefore, a label-free fluorescent "turn-on" sensor for the rapid detection of cysteine was designed, and the detection limit of this sensor was as low as 2.4 nM, which was much lower than those of the most of the previously reported cysteine sensors.

  17. NMR shielding tensors for density fitted local second-order Møller-Plesset perturbation theory using gauge including atomic orbitals.

    Science.gov (United States)

    Loibl, Stefan; Schütz, Martin

    2012-08-28

    An efficient method for the calculation of nuclear magnetic resonance (NMR) shielding tensors is presented, which treats electron correlation at the level of second-order Mo̸ller-Plesset perturbation theory. It uses spatially localized functions to span occupied and virtual molecular orbital spaces, respectively, which are expanded in a basis of gauge including atomic orbitals (GIAOs or London atomic orbitals). Doubly excited determinants are restricted to local subsets of the virtual space and pair energies with an interorbital distance beyond a certain threshold are omitted. Furthermore, density fitting is employed to factorize the electron repulsion integrals. Ordinary Gaussians are employed as fitting functions. It is shown that the errors in the resulting NMR shielding constant, introduced (i) by the local approximation and (ii) by density fitting, are very small or even negligible. The capabilities of the new program are demonstrated by calculations on some extended molecular systems, such as the cyclobutane pyrimidine dimer photolesion with adjacent nucleobases in the native intrahelical DNA double strand (ATTA sequence). Systems of that size were not accessible to correlated ab initio calculations of NMR spectra before. The presented method thus opens the door to new and interesting applications in this area.

  18. Radiometric 81Kr dating identifies 120,000 year old ice at Taylor Glacier, Antarctica

    CERN Document Server

    Buizert, Christo; Jiang, Wei; Purtschert, Roland; Petrenko, Vasilii V; Lu, Zheng-Tian; Mueller, Peter; Kuhl, Tanner; Lee, James; Severinghaus, Jeffrey P; Brook, Edward J

    2014-01-01

    We present the first successful 81Kr-Kr radiometric dating of ancient polar ice. Krypton was extracted from the air bubbles in four ~350 kg polar ice samples from Taylor Glacier in the McMurdo Dry Valleys, Antarctica, and dated using Atom Trap Trace Analysis (ATTA). The 81Kr radiometric ages agree with independent age estimates obtained from stratigraphic dating techniques with a mean absolute age offset of 6 +/- 2.5 ka. Our experimental methods and sampling strategy are validated by 1) 85Kr and 39Ar analyses that show the samples to be free of modern air contamination, and 2) air content measurements that show the ice did not experience gas loss. We estimate the error in the 81Kr ages due to past geomagnetic variability to be below 3 ka. We show that ice from the previous interglacial period (MIS 5e, 130-115 ka before present) can be found in abundance near the surface of Taylor Glacier. Our study paves the way for reliable radiometric dating of ancient ice in blue ice areas and margin sites where large samp...

  19. Prudent sperm use by leaf-cutter ant queens

    DEFF Research Database (Denmark)

    Den Boer, Susanne Petronella A; Baer, Boris; Dreier, Stéphanie Agnès Jeanine;

    2009-01-01

    In many species, females store sperm between copulation and egg fertilization, but the consequences of sperm storage and patterns of sperm use for female life history and reproductive success have not been investigated in great detail. In hymenopteran insect societies (ants, bees, wasps), reprodu......In many species, females store sperm between copulation and egg fertilization, but the consequences of sperm storage and patterns of sperm use for female life history and reproductive success have not been investigated in great detail. In hymenopteran insect societies (ants, bees, wasps......), reproduction is usually monopolized by one or relatively few queens, who mate only during a brief period early in life and store sperm for later use. The queens of some ants are particularly long-lived and have the potential to produce millions of offspring during their life. To do so, queens store many sperm...... cells, and this sperm must remain viable throughout the years of storage. Queens should also be under strong selection to use stored sperm prudently when fertilizing eggs. We used the leaf-cutter ant Atta colombica to investigate the dynamics of sperm use during egg fertilization. We show that queens...

  20. Leaf-cutter ant fungus gardens are biphasic mixed microbial bioreactors that convert plant biomass to polyols with biotechnological applications.

    Science.gov (United States)

    Somera, Alexandre F; Lima, Adriel M; Dos Santos-Neto, Álvaro J; Lanças, Fernando M; Bacci, Maurício

    2015-07-01

    Leaf-cutter ants use plant matter to culture the obligate mutualistic basidiomycete Leucoagaricus gongylophorus. This fungus mediates ant nutrition on plant resources. Furthermore, other microbes living in the fungus garden might also contribute to plant digestion. The fungus garden comprises a young sector with recently incorporated leaf fragments and an old sector with partially digested plant matter. Here, we show that the young and old sectors of the grass-cutter Atta bisphaerica fungus garden operate as a biphasic solid-state mixed fermenting system. An initial plant digestion phase occurred in the young sector in the fungus garden periphery, with prevailing hemicellulose and starch degradation into arabinose, mannose, xylose, and glucose. These products support fast microbial growth but were mostly converted into four polyols. Three polyols, mannitol, arabitol, and inositol, were secreted by L. gongylophorus, and a fourth polyol, sorbitol, was likely secreted by another, unidentified, microbe. A second plant digestion phase occurred in the old sector, located in the fungus garden core, comprising stocks of microbial biomass growing slowly on monosaccharides and polyols. This biphasic operation was efficient in mediating symbiotic nutrition on plant matter: the microbes, accounting for 4% of the fungus garden biomass, converted plant matter biomass into monosaccharides and polyols, which were completely consumed by the resident ants and microbes. However, when consumption was inhibited through laboratory manipulation, most of the plant polysaccharides were degraded, products rapidly accumulated, and yields could be preferentially switched between polyols and monosaccharides. This feature might be useful in biotechnology.

  1. Bacterial community composition and diversity in an ancestral ant fungus symbiosis.

    Science.gov (United States)

    Kellner, Katrin; Ishak, Heather D; Linksvayer, Timothy A; Mueller, Ulrich G

    2015-07-01

    Fungus-farming ants (Hymenoptera: Formicidae, Attini) exhibit some of the most complex microbial symbioses because both macroscopic partners (ants and fungus) are associated with a rich community of microorganisms. The ant and fungal microbiomes are thought to serve important beneficial nutritional and defensive roles in these symbioses. While most recent research has investigated the bacterial communities in the higher attines (e.g. the leaf-cutter ant genera Atta and Acromyrmex), which are often associated with antibiotic-producing Actinobacteria, very little is known about the microbial communities in basal lineages, labeled as 'lower attines', which retain the ancestral traits of smaller and more simple societies. In this study, we used 16S amplicon pyrosequencing to characterize bacterial communities of the lower attine ant Mycocepurus smithii among seven sampling sites in central Panama. We discovered that ant and fungus garden-associated microbiota were distinct from surrounding soil, but unlike the situation in the derived fungus-gardening ants, which show distinct ant and fungal microbiomes, microbial community structure of the ants and their fungi were similar. Another surprising finding was that the abundance of actinomycete bacteria was low and instead, these symbioses were characterized by an abundance of Lactobacillus and Pantoea bacteria. Furthermore, our data indicate that Lactobacillus strains are acquired from the environment rather than acquired vertically.

  2. Identification and functional characterization of a solute carrier family 15, member 4 gene in Litopenaeus vannamei.

    Science.gov (United States)

    Chen, Yong-Gui; Yuan, Kai; Zhang, Ze-Zhi; Yuan, Feng-Hua; Weng, Shao-Ping; Yue, Hai-Tao; He, Jian-Guo; Chen, Yi-Hong

    2016-04-01

    Innate immunity in shrimp is important in resisting bacterial infection. The NF-κB pathway is pivotal in such an immune response. This study cloned and functionally characterized the solute carrier family (SLC) 15 member A 4 (LvSLC15A4) gene in Litopenaeus vannamei. The open reading frame of LvSLC15A4 is 1, 902 bp long and encodes a putative 633-amino acid protein, which is localized in the plasma membrane and intracellular vesicular compartments. Results of the reporter gene assay showed that LvSLC15A4 upregulated NF-κB target genes, including the immediate-early gene 1 of white spot syndrome virus, as well as several antimicrobial peptide genes, such as pen4, CecA, AttA, and Mtk in S2 cells. Moreover, knocked-down expression of LvSLC15A4 reduced pen4 expression in L. vannamei. LvSLC15A4 down-regulation also increased the cumulative mortality of Vibrio parahemolyticus-infected L. vannamei. Furthermore, LvSLC15A4 expression was induced by unfolded protein response (UPR) in L. vannamei hematocytes. These results suggest that LvSLC15A4 participates in L. vannamei innate immunity via the NF-κB pathway and thus may be related to UPR.

  3. Emission of ions and charged soot particles by aircraft engines

    Directory of Open Access Journals (Sweden)

    A. Sorokin

    2003-01-01

    Full Text Available In this article, a model which examines the formation and evolution of chemiions in an aircraft engine is proposed. This model which includes chemiionisation, electron thermo-emission, electron attachment to soot particles and to neutral molecules, electron-ion and ion-ion recombination, ion-soot interaction, allows the determination of the ion concentration at the exit of the combustor and at the nozzle exit of the engine. It also allows the determination of the charge of the soot particles. For the engine considered, the upper limit for the ion emission index EIi is of the order of (2-5 x1016 ions/kg-fuel if ion-soot interactions are ignored and the introduction of ion-soot interactions lead about to a 50% reduction. The results also show that most of the soot particles are either positively or negatively charged, the remaining neutral particles representing approximately 20% of the total particles. A comparison of the model results with the available ground-based experimental data obtained on the ATTAS research aircraft engines during the SULFUR experiments (Schumann, 2002 shows an excellent agreement.

  4. Seminal fluid mediates ejaculate competition in social insects

    DEFF Research Database (Denmark)

    Den Boer, Susanne Petronella A; Baer, Boris; Boomsma, Jacobus Jan

    2010-01-01

    Queens of ants and bees normally obtain a lifetime supply of sperm on a single day of sexual activity, and sperm competition is expected to occur in lineages where queens receive sperm from multiple males. We compared singly mated (monandrous) and multiply mated (polyandrous) sister groups of ant...... and ants. In Atta leafcutter ants, the negative effect of the seminal fluid of other males was negated by secretion from the queen sperm-storage organ, suggesting that queens may control ejaculate competition after sperm storage.......Queens of ants and bees normally obtain a lifetime supply of sperm on a single day of sexual activity, and sperm competition is expected to occur in lineages where queens receive sperm from multiple males. We compared singly mated (monandrous) and multiply mated (polyandrous) sister groups of ants...... and bees and show that seminal fluid of polyandrous species has a more positive effect on the survival of a male's own sperm than on other males' sperm. This difference was not observed in the monandrous species, suggesting that incapacitation of competing sperm may have independently evolved in both bees...

  5. Nesting biology and fungiculture of the fungus-growing ant, Mycetagroicus cerradensis: new light on the origin of higher attine agriculture.

    Science.gov (United States)

    Solomon, Scott E; Lopes, Cauê T; Mueller, Ulrich G; Rodrigues, Andre; Sosa-Calvo, Jeffrey; Schultz, Ted R; Vasconcelos, Heraldo L

    2011-01-01

    The genus Mycetagroicus is perhaps the least known of all fungus-growing ant genera, having been first described in 2001 from museum specimens. A recent molecular phylogenetic analysis of the fungus-growing ants demonstrated that Mycetagroicus is the sister to all higher attine ants (Trachymyrmex, Sericomyrmex, Acromyrmex, Pseudoatta, and Atta), making it of extreme importance for understanding the transition between lower and higher attine agriculture. Four nests of Mycetagroicus cerradensis near Uberlândia, Minas Gerais, Brazil were excavated, and fungus chambers for one were located at a depth of 3.5 meters. Based on its lack of gongylidia (hyphal-tip swellings typical of higher attine cultivars), and a phylogenetic analysis of the ITS rDNA gene region, M. cerradensis cultivates a lower attine fungus in Clade 2 of lower attine (G3) fungi. This finding refines a previous estimate for the origin of higher attine agriculture, an event that can now be dated at approximately 21-25 mya in the ancestor of extant species of Trachymyrmex and Sericomyrmex.

  6. Aircraft exhaust aerosol formation and growth

    Energy Technology Data Exchange (ETDEWEB)

    Brown, R.C.; Miake-Lye, R.C.; Anderson, M.R.; Kolb, C.E. [Aerodyne Research, Inc., Billerica, MA (United States). Center for Chemical and Environmental Physics

    1997-12-31

    Aerosol formation and growth in the exhaust plume of the ATTAS aircraft at an altitude of approximately 9 km, burning fuels with 2 ppmm sulfur (`low`) and 266 ppmm (`high`) sulfur has been modeled using an aerosol dynamics model for nucleation, vapor condensation and coagulation, coupled to a 2-dimensional, axisymmetric flow code to treat plume dilution and turbulent mixing. For both the `low` and `high` sulfur fuels, approximately 60% of the available water had condensed within the first 200 m downstream of the exhaust exit. The contrail particle diameters ranged between 0.4 to 1.6 {mu}m. However, the size distributions as a function of radial position for the `low` sulfur plume were broader than the corresponding distributions for the `high` sulfur plume. The model results indicate for a fuel sulfur mass loading of 2 ppmm, sulfuric acid remains a viable activating agent and that the differences in the contrail particle size distributions for sulfur mass loadings between 2 ppmm and 260 ppmm would be difficult to detect. (author) 12 refs.

  7. 因子von Neumann代数上Jordan正交可导映射%Jordan orthogonal derivable mappings on factor von Neumann algebra

    Institute of Scientific and Technical Information of China (English)

    张芳娟

    2012-01-01

    Let.M be a factor von Neumann algebra acting on a complex separable Hilbert space .H with dim.H>2. Let φ: M→M be a Jordan orthogonal derivable bounded linear mapping from .M to itself, then there exist μ∈R, λ∈C and M∈M,M +M * =μ1 , such that φ>(A) = AM - MA + λA for all A∈M. If φ:M→M be a Jordan -* derivable mapping, then there exist μ∈ R and T ∈M,T +T* =μJ, such that φ(A) = AT-TA for all A∈M.%设M是作用在维数大于2的复可分Hilbert空间M上的因子von Neumann代数.若φ:M→M上有界的Jordan正交可导线性映射,则存在数μ∈R,λ∈C和算子M∈M,且M+M*=μl,使得对所有的A∈M,有φ(A) =AM-MA +λA.若φ:M→M上有界的Jordan -*可导线性映射,则存在数μ∈R和算子T∈M,且7+ T*=μl,使得对所有的A∈M,有φ(A) =AT- TA.

  8. CONTINUING EDUCATION AND SCHOOL INCLUSION: POTENTIALITIES FOR THE CONSTRUCTION OF NEW POSTURES AND PRACTICES OF EDUCATORS FROM THE MUNICIPAL TEACHING NETWORK OF PRESIDENTE PRUDENTE

    Directory of Open Access Journals (Sweden)

    Simone Maria Carlos Gakiya

    2013-07-01

    Full Text Available The present work is a part of a research master's concerns continued training of teachers and school enrollment and consisted in analyzing the manifestations of educators articipating in the Continuing Education Course in Assistive Technology (AT-TA about their understandings, attitudes and practices regarding school inclusion of people with disabilities in municipal schools of Presidente Prudente/SP. The methodology adopted for data acquisition involved the reading of the documents produced by participants in the virtual learning environment (VLE-AVA TelEduc, because it is a course conducted through the modality of Distance Education (DE-EaD, and the application questionnaire and interview. The results revealed the personal dilemmas experienced with the process of inclusion expressed by feelings of insecurity, distrust, lack of professional training, fear of the new, the different, the influence of cultural, social and historical in conceptions, beliefs, values and pedagogical relationships; initial training that did not include the dilemmas experienced in the classroom; Public Policies, laws, guidelines not mobilized the occurrence of new attitudes and practices. In this study we sought to highlight the potential for the occurrence of the formation of new attitudes of educators face in the process of school inclusion.

  9. Influences of Pr and Ta doping concentration on the characteristic features of FTO thin film deposited by spray pyrolysis

    Institute of Scientific and Technical Information of China (English)

    G ¨uven Turgut; Adem Koc¸ yi˘git; Erdal S ¨onmez

    2015-01-01

    The Pr and Ta separately doped FTO (10 at.%F incorporated SnO2) films are fabricated via spray pyrolysis. The mi-crostructural, topographic, optical, and electrical features of fl uorine-doped TO (FTO) films are investigated as functions of Pr and Ta dopant concentrations. The x-ray diffraction (XRD) measurements reveal that all deposited films show polycrys-talline tin oxide crystal property. FTO film has (200) preferential orientation, but this orientation changes to (211) direction with Pr and Ta doping ratio increasing. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) anal-yses show that all films have uniform and homogenous nanoparticle distributions. Furthermore, morphologies of the films depend on the ratio between Pr and Ta dopants. From ultraviolet-visible (UV-Vis) spectrophotometer measurements, it is shown that the transmittance value of FTO film decreases with Pr and Ta doping elements increasing. The band gap value of FTO film increases only at 1 at.%Ta doping level, it drops off with Pr and Ta doping ratio increasing at other doped FTO films. The electrical measurements indicate that the sheet resistance value of FTO film initially decreases with Pr and Ta doping ratio decreasing and then it increases with Pr and Ta doping ratio increasing. The highest value of figure of merit is obtained for 1 at.%Ta-and Pr-doped FTO film. These results suggest that Pr-and Ta-doped FTO films may be appealing candidates for TCO applications.

  10. Isolation and molecular characterization of symbiotic fungus from Acromyrmex ambiguus and Acromyrmex heyeri ants of Rio Grande do Sul State, Brazil

    Directory of Open Access Journals (Sweden)

    Daniela Isabel Brayer Pereira

    2015-07-01

    Full Text Available Leaf-cutting ants of the genera Atta and Acromyrmex determine serious agricultural problems and live on symbiosis with Leucoagaricus gongylophorus. The aim of this study is to identify morphological and molecularly, as well as to verify the genotypic variability of the symbiotic fungus cultivated by A. heyeri and A. ambiguus from three different regions of the state of Rio Grande do Sul, Brazil. Fungus gardens were collected and fragments of mycelia were grown in selective medium. Total DNA was extracted and amplification of the ITS region was performed by PCR using universal primers. After DNA sequencing, the chromatograms were assembled and phylogenetic analyzes were performed by the Neighbor-Joining method. A total of six isolates of L. gongylophorus were obtained and their identities were confirmed by molecular analyses. Phylogenetic analysis of the ITS region showed a tree with two distinct groups regarding the fungus isolates from A. heiyeri and A. ambiguous. In this study, it was verified that A. heyeri and A. ambiguous, cultivate the same fungus. Additionally, the molecular marker used in this study showed variations in L. gongylophorus, evidencing two distinct branches in the phylogenetic tree, according to the ant species that cultivate L. gongylophorus. However, other studies involving the inclusion of a great number of isolates of L. gongylophorus, as well as the use of other molecular markers to validate the possible variations in the phylogenetic relationship of this symbiotic fungus are required.

  11. Discovery of defense- and neuropeptides in social ants by genome-mining.

    Directory of Open Access Journals (Sweden)

    Christian W Gruber

    Full Text Available Natural peptides of great number and diversity occur in all organisms, but analyzing their peptidome is often difficult. With natural product drug discovery in mind, we devised a genome-mining approach to identify defense- and neuropeptides in the genomes of social ants from Atta cephalotes (leaf-cutter ant, Camponotus floridanus (carpenter ant and Harpegnathos saltator (basal genus. Numerous peptide-encoding genes of defense peptides, in particular defensins, and neuropeptides or regulatory peptide hormones, such as allatostatins and tachykinins, were identified and analyzed. Most interestingly we annotated genes that encode oxytocin/vasopressin-related peptides (inotocins and their putative receptors. This is the first piece of evidence for the existence of this nonapeptide hormone system in ants (Formicidae and supports recent findings in Tribolium castaneum (red flour beetle and Nasonia vitripennis (parasitoid wasp, and therefore its confinement to some basal holometabolous insects. By contrast, the absence of the inotocin hormone system in Apis mellifera (honeybee, another closely-related member of the eusocial Hymenoptera clade, establishes the basis for future studies on the molecular evolution and physiological function of oxytocin/vasopressin-related peptides (vasotocin nonapeptide family and their receptors in social insects. Particularly the identification of ant inotocin and defensin peptide sequences will provide a basis for future pharmacological characterization in the quest for potent and selective lead compounds of therapeutic value.

  12. Enrichment and Broad Representation of Plant Biomass-Degrading Enzymes in the Specialized Hyphal Swellings of Leucoagaricus gongylophorus, the Fungal Symbiont of Leaf-Cutter Ants

    Energy Technology Data Exchange (ETDEWEB)

    Aylward, Frank O.; Khadempour, Lily; Tremmel, Daniel; McDonald, Bradon R.; Nicora, Carrie D.; Wu, Si; Moore, Ronald J.; Orton, Daniel J.; Monroe, Matthew E.; Piehowski, Paul D.; Purvine, Samuel O.; Smith, Richard D.; Lipton, Mary S.; Burnum-Johnson, Kristin E.; Currie, Cameron R.

    2015-08-28

    Leaf-cutter ants are prolific and conspicuous Neotropical herbivores that derive energy from specialized fungus gardens they cultivate using foliar biomass. The basidiomycetous cultivar of the ants, Leucoagaricus gongylophorus, produces specialized hyphal swellings called gongylidia that serve as the primary food source of ant colonies. Gongylidia also contain lignocellulases that become concentrated in ant digestive tracts and are deposited within fecal droplets onto fresh foliar material as it is foraged by the ants. Although the enzymes concentrated by L. gongylophorus within gongylidia are thought to be critical to the initial degradation of plant biomass, only a few enzymes present in these hyphal swellings have been identified. Here we use proteomic methods to identify proteins present in the gongylidia of three Atta cephalotes colonies. Our results demonstrate that a diverse but consistent set of enzymes is present in gongylidia, including numerous lignocellulases likely involved in the degradation of polysaccharides, plant toxins, and proteins. Overall, gongylidia contained over three-quarters of all lignocellulases identified in the L. gongylophorus genome, demonstrating that the majority of the enzymes produced by this fungus for biomass breakdown are ingested by the ants. We also identify a set of 23 lignocellulases enriched in gongylidia compared to whole fungus garden samples, suggesting that certain enzymes may be particularly important in the initial degradation of foliar material. Our work sheds light on the complex interplay between leaf-cutter ants and their fungal symbiont that allows for the host insects to occupy an herbivorous niche by indirectly deriving energy from plant biomass.

  13. Chemical composition of metapleural gland secretions of fungus-growing and non-fungus-growing ants.

    Science.gov (United States)

    Vieira, Alexsandro S; Morgan, E David; Drijfhout, Falko P; Camargo-Mathias, Maria I

    2012-10-01

    The metapleural gland is exclusive to ants, and unusual among exocrine glands in having no mechanism for closure and retention of secretion. As yet, no clear conclusion has been reached as to the function of metapleural gland secretion. Metapleural gland secretions were investigated for fungus-growing ants representing the derived attines Trachymyrmex fuscus, Atta laevigata, and Acromyrmex coronatus, the basal attines Apterostigma pilosum and Mycetarotes parallelus, and non-fungus-growing ants of the tribes Ectatommini (Ectatomma brunneum) and Myrmicini (Pogonomyrmex naegeli). Our results showed that the secretions of leaf-cutting ants (A. laevigata and A. coronatus) and the derived attine, T. fuscus, contain a greater variety and larger quantities of volatile compounds than those of myrmicine and ectatommine ants. The most abundant compounds found in the metapleural glands of A. laevigata and A. coronatus were hydroxyacids, and phenylacetic acid (only in A. laevigata). Indole was present in all groups examined, while skatole was found in large quantities only in attines. Ketones and aldehydes are present in the secretion of some attines. Esters are present in the metapleural gland secretion of all species examined, although mainly in A. laevigata, A. coronatus, and T. fuscus. Compared with basal attines and non-fungus-growing ants, the metapleural glands of leaf-cutting ants produce more acidic compounds that may have an antibiotic or antifungal function.

  14. Broad Escovopsis-inhibition activity of Pseudonocardia associated with Trachymyrmex ants.

    Science.gov (United States)

    Meirelles, Lucas A; Mendes, Thaís D; Solomon, Scott E; Bueno, Odair C; Pagnocca, Fernando C; Rodrigues, Andre

    2014-08-01

    Attine ants maintain an association with antibiotic-producing Actinobacteria found on their integuments. Evidence supports these bacteria as auxiliary symbionts that help ants to defend the fungus gardens against pathogens. Using Pseudonocardia strains isolated from Trachymyrmex ants, we tested whether the inhibitory capabilities of such strains are restricted to Escovopsis parasites that infect gardens of this ant genus. Twelve Pseudonocardia strains were tested in in vitro bioassays against Escovopsis strains derived from fungus gardens of Trachymyrmex (n = 1) and leaf-cutting ants (n = 3). Overall, significant differences were observed in the mycelial growth among each Escovopsis strain in the presence of Pseudonocardia. Particularly, Escovopsis from Acromyrmex and Trachymyrmex were the most inhibited strains in comparison to Escovopsis isolated from Atta. This result suggests that Pseudonocardia isolated from Trachymyrmex possibly secrete antimicrobial compounds effective against diverse Escovopsis strains. The fact that Trachymyrmex ants harbour Pseudonocardia strains with broad spectrum of activity and its defensive role on attine gardens are discussed.

  15. Study of pulmonary (lung) functioning of commercial wheat grinding machine operators in India using spirometric testing.

    Science.gov (United States)

    Agashe, Abhijeet; Deshpande, V S

    2010-04-01

    In ancient times, in India each household had a chakki to mill the wheat. There was no concept of getting wheat grounded from outside. With the fast changing lifestyle, this tradition has almost disappeared now. Today every city of India has numerous commercial wheat grinding machine shops located at various places. Other than states like Punjab, this occupation is mostly unorganized and little has been done to look into the welfare and health of these machine operators. Like most of the occupations, this occupation of wheat grinding also has several occupational hazards and injuries associated with it. The most obvious of them all in this case is due to the continuous exposure of the operators to the rising dust wheat particles, commonly called atta). This perpetual inhaling ofpollutants exposes the operators to risks of pulmonary malfunctioning. Therefore, this paper attempts to determine the pulmonary functioning of the commercial wheat grinding machine operators in India using spirometric testing. On the basis of the anthropometric data, effort has been done to develop the expected lung performance. Further, the actual lung performance of the operators is measured and compared with expected performance.

  16. The EAGLE project: Simulating the evolution and assembly of galaxies and their environments

    CERN Document Server

    Schaye, Joop; Bower, Richard G; Furlong, Michelle; Schaller, Matthieu; Theuns, Tom; Vecchia, Claudio Dalla; Frenk, Carlos S; McCarthy, I G; Helly, John C; Jenkins, Adrian; Rosas-Guevara, Y M; White, Simon D M; Baes, Maarten; Booth, C M; Camps, Peter; Navarro, Julio F; Qu, Yan; Rahmati, Alireza; Sawala, Till; Thomas, Peter A; Trayford, James

    2014-01-01

    We introduce the Virgo Consortium's EAGLE project, a suite of hydrodynamical simulations that follow the formation of galaxies and black holes in representative volumes. We discuss the limitations of such simulations in light of their finite resolution and poorly constrained subgrid physics, and how these affect their predictive power. One major improvement is our treatment of feedback from massive stars and AGN in which thermal energy is injected into the gas without the need to turn off cooling or hydrodynamical forces, allowing winds to develop without predetermined speed or mass loading factors. Because the feedback efficiencies cannot be predicted from first principles, we calibrate them to the z~0 galaxy stellar mass function and the amplitude of the galaxy-central black hole mass relation, also taking galaxy sizes into account. The observed galaxy mass function is reproduced to $\\lesssim 0.2$ dex over the full mass range, $10^8 < M_*/M_\\odot \\lesssim 10^{11}$, a level of agreement close to that atta...

  17. Minimal subspace rotation on the Stiefel manifold for stabilization and enhancement of projection-based reduced order models for the compressible Navier-Stokes equations

    CERN Document Server

    Balajewicz, Maciej; Dowell, Earl

    2015-01-01

    For a projection-based reduced order model (ROM) to be stable and accurate, the dynamics of the truncated subspace must be taken into account. This paper proposes an approach for stabilizing and enhancing projection-based fluid ROMs in which truncated modes are accounted for \\textit{a priori} via a minimal rotation of the projection subspace. Attention is focused on the full non-linear compressible Navier-Stokes equations in specific volume form as a step toward a more general formulation for problems with generic non-linearities. Unlike traditional approaches, no empirical turbulence modeling terms are required, and consistency between the ROM and the full order model from which the ROM is derived is maintained. Mathematically, the approach is formulated as a quadratic matrix program on the Stiefel manifold. The reproductive as well as predictive capabilities of the method are evaluated on several compressible flow problems, including a problem involving laminar flow over an airfoil with a high angle of atta...

  18. 3ynamic Adsorption of Microwave Modified Attapulgite on Micro-polluted Phenol Wastewater

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    [Objective] The paper was to study the dynamic adsorption of microwave modified attapulgite on micro-polluted phenol wastewater. [Method] Cetyl trimethyl ammonium bromide (CATB) modified attapulgite was used to modify attapulgite, and conducted dynamic test on micro-polluted phenol wastewater. The dynamic charac- teristics of phenol removal were also studied. [Result] Attapulgite modified by CATB has strong adsorption ability on phenol in micro-polluted water, the phenol removal rate increased with the decrease of flow rate of wastewater. When pH value was 6- 8, phenol concentration in wastewater was 17.74 mg/L, flow rate was 2 m/s and ad- sorption time was 25 rain, the removal rate reached 93.07%. The modified atta- pulgite could be regenerated with alkali, and its adsorption ability after regeneration had no obvious decline. The dynamic adsorption process of phenol accorded with the first-order kinetic equation. [Conclusion] The study provided basis for further study on "organic matter removal in wastewater.

  19. Favourite distances in high dimensions

    CERN Document Server

    Swanepoel, Konrad J

    2011-01-01

    Let $S$ be a set of $n$ points in $d$-dimensional Euclidean space. Assign to each $x\\in S$ an arbitrary distance $r(x)>0$. Let $e_r(x,S)$ denote the number of points in $S$ at distance $r(x)$ from $x$. Avis, Erd\\"os and Pach (1988) introduced the extremal quantity $f_d(n)=\\max\\sum_{x\\in S}e_r(x,S)$, where the maximum is taken over all $n$-point sets $S$ in $d$-dimensional space and all assignments $r\\colon S\\to(0,\\infty)$ of distances. We give a quick derivation of the asymptotics of the error term of $f_d(n)$ using only the analogous asymptotics of the maximum number of unit distance pairs in a set of $n$ points, which improves on previous results of Avis, Erd\\"os and Pach (1988) and Erd\\"os and Pach (1990). Then we prove a stability result for $d\\geq 4$, asserting that if $(S,r)$ with $|S|=n$ satisfies $e_r(S)=f_d(n)-o(n^2)$, then, up to $o(n)$ points, $S$ is a Lenz construction with $r$ constant. Finally we use stability to show that for $n$ sufficiently large (depending on $d$) the pairs $(S,r)$ that atta...

  20. Involvement of Relish gene from Macrobrachium rosenbergii in the expression of anti-microbial peptides.

    Science.gov (United States)

    Shi, Yan-Ru; Jin, Min; Ma, Fu-Tong; Huang, Ying; Huang, Xin; Feng, Jin-Ling; Zhao, Ling-Ling; Chen, Yi-Hong; Ren, Qian

    2015-10-01

    Relish is an NF-kB transcription factor involved in immune-deficiency (IMD) signal pathway. In this study, a Relish gene (MrRelish) was identified from Macrobrachium rosenbergii. The full length of MrRelish comprises 5072 bp, including a 3510 bp open reading frame encoding a 1169 bp amino acid protein. MrRelish contains a Rel homology domain (RHD), a nucleus localization signal, an IκB-like domain (6 ankyrin repeats), and a death domain. Phylogenetic analysis showed that MrRelish and other Relish from crustaceans belong to one group. MrRelish was expressed in all detected tissues, with the highest expression level in hemocytes and intestines. MrRelish was also upregulated in hepatopancreas at 6 h after Vibrio anguillarum challenge. The over-expression of MrRelish could induce the expression of antimicrobial peptides (AMPs), such as Drosophila Metchnikowin (Mtk), Attacin (Atta), Drosomycin (Drs), and Cecropin (CecA) and shrimp Penaeidin (Pen4). The RNAi of MrRelish in gills showed that the expression of crustin (cru) 2, Cru5, Cru8, lysozyme (Lyso) 1, and Lyso2 was inhibited. However, the expression of anti-lipopolysaccharide factor (ALF) 1 and ALF3 did not change when MrRelish was knocked down. These results indicate that MrRelish may play an important role in innate immune defense against V. anguillarum in M. rosenbergii.

  1. All-optical production and trapping of metastable noble gas atoms down to the single atom regime

    CERN Document Server

    Kohler, M; Sahling, P; Sieveke, C; Jerschabek, N; Kalinowski, M B; Becker, C; Sengstock, K

    2014-01-01

    The determination of isotope ratios of noble gas atoms has many applications e.g. in physics, nuclear arms control, and earth sciences. For several applications, the concentration of specific noble gas isotopes (e.g. Kr and Ar) is so low that single atom detection is highly desirable for a precise determination of the concentration. As an important step in this direction, we demonstrate operation of a krypton Atom Trap Trace Analysis (ATTA) setup based on a magneto-optical trap (MOT) for metastable Kr atoms excited by all-optical means. Compared to other state-of-the-art techniques for preparing metastable noble gas atoms, all-optical production is capable of overcoming limitations regarding minimal probe volume and avoiding cross-contamination of the samples. In addition, it allows for a compact and reliable setup. We identify optimal parameters of our experimental setup by employing the most abundant isotope Kr-84, and demonstrate single atom detection within a 3D MOT.

  2. Generation of Nutrients and Detoxification: Possible Roles of Yeasts in Leaf-Cutting Ant Nests

    Directory of Open Access Journals (Sweden)

    Fernando C. Pagnocca

    2012-02-01

    Full Text Available The possible roles played by yeasts in attine ant nests are mostly unknown. Here we present our investigations on the plant polysaccharide degradation profile of 82 yeasts isolated from fungus gardens of Atta and Acromyrmex species to demonstrate that yeasts found in ant nests may play the role of making nutrients readily available throughout the garden and detoxification of compounds that may be deleterious to the ants and their fungal cultivar. Among the yeasts screened, 65% exhibited cellulolytic enzymes, 44% exhibited pectinolytic activity while 27% and 17% possess enzyme systems for the degradation of protease and amylase, respectively. Galacturonic acid, which had been reported in previous work to be poorly assimilated by the ant fungus and also to have a negative effect on ants’ survival, was assimilated by 64% and 79% of yeasts isolated from nests of A. texana and Acromyrmex respectively. Our results suggest that yeasts found in ant nests may participate in generation of nutrients and removal of potentially toxic compounds, thereby contributing to the stability of the complex microbiota found in the leaf-cutting ant nests.

  3. Evolution of cold-tolerant fungal symbionts permits winter fungiculture by leafcutter ants at the northern frontier of a tropical ant-fungus symbiosis.

    Science.gov (United States)

    Mueller, Ulrich G; Mikheyev, Alexander S; Hong, Eunki; Sen, Ruchira; Warren, Dan L; Solomon, Scott E; Ishak, Heather D; Cooper, Mike; Miller, Jessica L; Shaffer, Kimberly A; Juenger, Thomas E

    2011-03-08

    The obligate mutualism between leafcutter ants and their Attamyces fungi originated 8 to 12 million years ago in the tropics, but extends today also into temperate regions in South and North America. The northernmost leafcutter ant Atta texana sustains fungiculture during winter temperatures that would harm the cold-sensitive Attamyces cultivars of tropical leafcutter ants. Cold-tolerance of Attamyces cultivars increases with winter harshness along a south-to-north temperature gradient across the range of A. texana, indicating selection for cold-tolerant Attamyces variants along the temperature cline. Ecological niche modeling corroborates winter temperature as a key range-limiting factor impeding northward expansion of A. texana. The northernmost A. texana populations are able to sustain fungiculture throughout winter because of their cold-adapted fungi and because of seasonal, vertical garden relocation (maintaining gardens deep in the ground in winter to protect them from extreme cold, then moving gardens to warmer, shallow depths in spring). Although the origin of leafcutter fungiculture was an evolutionary breakthrough that revolutionized the food niche of tropical fungus-growing ants, the original adaptations of this host-microbe symbiosis to tropical temperatures and the dependence on cold-sensitive fungal symbionts eventually constrained expansion into temperate habitats. Evolution of cold-tolerant fungi within the symbiosis relaxed constraints on winter fungiculture at the northern frontier of the leafcutter ant distribution, thereby expanding the ecological niche of an obligate host-microbe symbiosis.

  4. Discovery of defense- and neuropeptides in social ants by genome-mining.

    Science.gov (United States)

    Gruber, Christian W; Muttenthaler, Markus

    2012-01-01

    Natural peptides of great number and diversity occur in all organisms, but analyzing their peptidome is often difficult. With natural product drug discovery in mind, we devised a genome-mining approach to identify defense- and neuropeptides in the genomes of social ants from Atta cephalotes (leaf-cutter ant), Camponotus floridanus (carpenter ant) and Harpegnathos saltator (basal genus). Numerous peptide-encoding genes of defense peptides, in particular defensins, and neuropeptides or regulatory peptide hormones, such as allatostatins and tachykinins, were identified and analyzed. Most interestingly we annotated genes that encode oxytocin/vasopressin-related peptides (inotocins) and their putative receptors. This is the first piece of evidence for the existence of this nonapeptide hormone system in ants (Formicidae) and supports recent findings in Tribolium castaneum (red flour beetle) and Nasonia vitripennis (parasitoid wasp), and therefore its confinement to some basal holometabolous insects. By contrast, the absence of the inotocin hormone system in Apis mellifera (honeybee), another closely-related member of the eusocial Hymenoptera clade, establishes the basis for future studies on the molecular evolution and physiological function of oxytocin/vasopressin-related peptides (vasotocin nonapeptide family) and their receptors in social insects. Particularly the identification of ant inotocin and defensin peptide sequences will provide a basis for future pharmacological characterization in the quest for potent and selective lead compounds of therapeutic value.

  5. Leucoagaricus gongylophorus produces diverse enzymes for the degradation of recalcitrant plant polymers in leaf-cutter ant fungus gardens.

    Science.gov (United States)

    Aylward, Frank O; Burnum-Johnson, Kristin E; Tringe, Susannah G; Teiling, Clotilde; Tremmel, Daniel M; Moeller, Joseph A; Scott, Jarrod J; Barry, Kerrie W; Piehowski, Paul D; Nicora, Carrie D; Malfatti, Stephanie A; Monroe, Matthew E; Purvine, Samuel O; Goodwin, Lynne A; Smith, Richard D; Weinstock, George M; Gerardo, Nicole M; Suen, Garret; Lipton, Mary S; Currie, Cameron R

    2013-06-01

    Plants represent a large reservoir of organic carbon comprised primarily of recalcitrant polymers that most metazoans are unable to deconstruct. Many herbivores gain access to nutrients in this material indirectly by associating with microbial symbionts, and leaf-cutter ants are a paradigmatic example. These ants use fresh foliar biomass as manure to cultivate gardens composed primarily of Leucoagaricus gongylophorus, a basidiomycetous fungus that produces specialized hyphal swellings that serve as a food source for the host ant colony. Although leaf-cutter ants are conspicuous herbivores that contribute substantially to carbon turnover in Neotropical ecosystems, the process through which plant biomass is degraded in their fungus gardens is not well understood. Here we present the first draft genome of L. gongylophorus, and, using genomic and metaproteomic tools, we investigate its role in lignocellulose degradation in the gardens of both Atta cephalotes and Acromyrmex echinatior leaf-cutter ants. We show that L. gongylophorus produces a diversity of lignocellulases in ant gardens and is likely the primary driver of plant biomass degradation in these ecosystems. We also show that this fungus produces distinct sets of lignocellulases throughout the different stages of biomass degradation, including numerous cellulases and laccases that likely play an important role in lignocellulose degradation. Our study provides a detailed analysis of plant biomass degradation in leaf-cutter ant fungus gardens and insight into the enzymes underlying the symbiosis between these dominant herbivores and their obligate fungal cultivar.

  6. Ecology of microfungal communities in gardens of fungus-growing ants (Hymenoptera: Formicidae): a year-long survey of three species of attine ants in Central Texas.

    Science.gov (United States)

    Rodrigues, Andre; Mueller, Ulrich G; Ishak, Heather D; Bacci, Maurício; Pagnocca, Fernando C

    2011-11-01

    We profiled the microfungal communities in gardens of fungus-growing ants to evaluate possible species-specific ant-microfungal associations and to assess the potential dependencies of microfungal diversity on ant foraging behavior. In a 1-year survey, we isolated microfungi from nests of Cyphomyrmex wheeleri, Trachymyrmex septentrionalis and Atta texana in Central Texas. Microfungal prevalence was higher in gardens of C. wheeleri (57%) than in the gardens of T. septentrionalis (46%) and A. texana (35%). Culture-dependent methods coupled with a polyphasic approach of species identification revealed diverse and changing microfungal communities in all the sampling periods. Diversity analyses showed no obvious correlations between the number of observed microfungal species, ant species, or the ants' changing foraging behavior across the seasons. However, both correspondence analysis and 5.8S-rRNA gene unifrac analyses suggested structuring of microfungal communities by ant host. These host-specific differences may reflect in part the three different environments where ants were collected. Most interestingly, the specialized fungal parasite Escovopsis was not isolated from any attine garden in this study near the northernmost limit of the range of attine ants, contrasting with previous studies that indicated a significant incidence of this parasite in ant gardens from Central and South America. The observed differences of microfungal communities in attine gardens suggest that the ants are continuously in contact with a diverse microfungal species assemblage.

  7. Weeding and grooming of pathogens in agriculture by ants.

    Science.gov (United States)

    Currie, C R; Stuart, A E

    2001-05-22

    The ancient mutualism between fungus-growing ants and the fungi they cultivate for food is a textbook example of symbiosis. Fungus-growing ants' ability to cultivate fungi depends on protection of the garden from the aggressive microbes associated with the substrate added to the garden as well as from the specialized virulent garden parasite Escovopsis. We examined ants' ability to remove alien microbes physically by infecting Atta colombica gardens with the generalist pathogen Trichoderma viride and the specialist pathogen Escovopsis. The ants sanitized the garden using two main behaviours: grooming of alien spores from the garden (fungus grooming) and removal of infected garden substrate (weeding). Unlike previously described hygienic behaviours (e.g. licking and self-grooming), fungus-grooming and garden-removal behaviours are specific responses to the presence of fungal pathogens. In the presence of pathogens, they are the primary activities performed by workers, but they are uncommon in uninfected gardens. In fact, workers rapidly eliminate Trichoderma from their gardens by fungus grooming and weeding, suggesting that these behaviours are the primary method of garden defence against generalist pathogens. The same sanitary behaviours were performed in response to the presence of the specialist pathogen Escovopsis. However, the intensity and duration of these behaviours were much greater in this treatment. Despite the increased effort, the ants were unable to eliminate Escovopsis from their gardens, suggesting that this specialized pathogen has evolved counter-adaptations in order to overcome the sanitary defences of the ants.

  8. Turbulent mixing driven by mean-flow shear and internal gravity waves in oceans and atmospheres

    CERN Document Server

    Baumert, Helmut Z

    2012-01-01

    This study starts with balances deduced by Baumert and Peters (2004, 2005) from results of stratified-shear experiments made in channels and wind tunnels by Itsweire (1984) and Rohr and Van Atta (1987), and of free-decay experiments in a resting stratified tank by Dickey and Mellor (1980). Using a modification of Canuto's (2002) ideas on turbulence and waves, these balances are merged with an (internal) gravity-wave energy balance presented for the open ocean by Gregg (1989), without mean-flow shear. The latter was augmented by a linear (viscous) friction term. Gregg's wave-energy source is interpreted on its long-wave spectral end as internal tides, topography, large-scale wind, and atmospheric low-pressure actions. In addition, internal eigen waves, generated by mean-flow shear, and the aging of the wave field from a virginal (linear) into a saturated state are taken into account. Wave packets and turbulence are treated as particles (vortices, packets) by ensemble kinetics so that the loss terms in all thre...

  9. KONTRIBUSI PEMIKIRAN ISLAM KONTEMPORER BAGI PENGEMBANGAN FILSAFAT ILMU-ILMU KEISLAMAN

    Directory of Open Access Journals (Sweden)

    Fuad Ramly

    2014-12-01

    Full Text Available Pengembangan Filsafat Ilmu-ilmu Keislaman dapat dilakukan dengan merumuskan kembali landasan ontologis, landasan epistemologis, dan landasan aksiologis ilmu yang bersumber dari kontribusi pemikiran Nasr, al-Attas, dan Sardar. Landasan ontologis tersebut menentukan wilayah objek kajian Ilmu-ilmu Keislaman, yang meliputi aspek-aspek metafisika dan empiris. Landasan epistemologis mengakomodir keragaman (pluralitas metodologis (berbagai prosedur atau cara mengkaji ilmu, sesuai dengan kebutuhan intelektual masyarakat Islam. Landasan aksiologis mengarahkan dan menuntun pemahaman ontologis dan epistemologis tersebut sesuai dengan nilai-nilaidasar Islam. Berdasarkan ketiga landasan tersebut, pengembangan Filsafat Ilmu-ilmu Keislaman dapat dilakukan secara terpadu (integratif, tidak hanya dengan menumbuhkan kesadaran historis untuk menggali khazanah kemajuan intelektual Islam masa lalu, tetapi sekaligus juga dengan merespon kemajuan-kemajuan metodologi masa kini yang relevan dengan nilai-nilai intelektual Islam yang kekal dan universal.Kata kunci: Pemikiran Islam Kontemporer; landasan filosofis; Filsafat Ilmu-ilmu Keislaman.

  10. Lifetimes, branching ratios, and Landé g values for (4d+5s)^7 and (4d+5s)^6 5p states in Tc uc(i)

    Science.gov (United States)

    O'Malley, Steven M.; Beck, Donald R.

    2002-05-01

    Relativistic Configuration Interaction (RCI) calculations suggest the ^6D^e_9/2 arrow ^6F^o_11/2 transition in Tc uc(i) as a possible candidate for Atomic Trap Trace Analysis(C. Y. Chen, Y. M. Li, K. Bailey, T. P. O'Connor, L. Young, and Z.-T. Lu, Science 286), 1139 (1999). (ATTA) studies. We present lifetimes and Landé g values for J= 5/2 -- 11/2 odd parity levels and J= 3/2 -- 9/2 even parity levels with branching ratios for the most important transitions. The increasing complexity of (d+s)^n/(d+s)^n-1p (n=7 in this case) calculations provides additional computational challenges compared to our earlier calculations (e.g. n=4 in Fe uc(v(S.) M. O'Malley, D. R. Beck, and D. P. Oros, Phys. Rev. A 63), 032501 (2001).). Changes in codes and computational techniques needed to accommodate this increased complexity of our basis sets and issues of loss of accuracy (relative to earlier work) in calculated energy spectra and f value gauge agreement are also presented.

  11. Discriminant analysis with errors in variables

    CERN Document Server

    Loustau, Sébastien

    2012-01-01

    The effect of measurement error in discriminant analysis is investigated. Given observations $Z=X+\\epsilon$, where $\\epsilon$ denotes a random noise, the goal is to predict the density of $X$ among two possible candidates $f$ and $g$. We suppose that we have at our disposal two learning samples. The aim is to approach the best possible decision rule $G^*$ defined as a minimizer of the Bayes risk. In the free-noise case $(\\epsilon=0)$, minimax fast rates of convergence are well-known under the margin assumption in discriminant analysis (see \\cite{mammen}) or in the more general classification framework (see \\cite{tsybakov2004,AT}). In this paper we intend to establish similar results in the noisy case, i.e. when dealing with errors in variables. In particular, we discuss two possible complexity assumptions that can be set on the problem, which may alternatively concern the regularity of $f-g$ or the boundary of $G^*$. We prove minimax lower bounds for these both problems and explain how can these rates be atta...

  12. I cataloghi nella letteratura americana della Grande Depressione

    Directory of Open Access Journals (Sweden)

    Cinzia Scarpino

    2011-07-01

    Full Text Available Il presente saggio si propone di analizzare alcune opere letterarie in senso lato (poesie, libri-documentario, script di film-documetario scritte negli Stati Uniti negli anni della Grande Depressione (1929-1941 alla luce della presenza ricorrente di cataloghi, liste e inventari. Partendo da un excursus storico circa la centralità del catalogo come forma narrativa atta a rendere l’abbondanza del Nuovo Mondo nella cultura e nella letteratura dell’Ottocento (dai diari dei primi esploratori agli scritti di Thomas Jefferson, dalle geremiadi puritane agli almanacchi e ai diari rurali, dalle teorizzazioni estetiche di Ralph Waldo Emerson al «poeta catalogatore» Walt Whitman e al Walden di H. D. Thoreau, il saggio si sofferma su alcune opere-documentario degli anni Trenta del Novecento; un periodo che, segnato profondamente dalla crisi economica e testimone di una riconfigurazione della geografia reale e simbolica del territorio nazionale, punta nuovamente a cataloghi e inventari, secondo una scelta retorica funzionale alla rappresentazione del rovescio del mito di abbondanza delle origini.

  13. Efficient visible and near-infrared photoluminescent attapulgite-based lanthanide one-dimensional nanomaterials assembled by ion-pairing interactions.

    Science.gov (United States)

    Xu, Jun; Zhang, Ye; Chen, Hao; Liu, Weisheng; Tang, Yu

    2014-06-07

    Attapulgite, a one-dimensional fibrillar nanomaterial present in nature, with its extreme stability, is a promising material to act as a new carrier of luminescent lanthanide complexes for further applications. Herein, a series of lanthanide complexes Na[Ln(TTA)4] have been attached to attapulgite (Atta) via ion-pairing interactions, generating the first example of attapulgite-based visible and near-infrared (NIR) luminescent lanthanide one-dimensional nanomaterials, where TTA is 2-thenoyltrifluoroacetonate and Ln is Eu, Sm, Nd, Er or Yb. The hybrid materials were characterized by CHN elemental analysis, inductively coupled plasma-atomic emission spectroscopy (ICP), powder X-ray diffraction (PXRD), thermogravimetry (TG), transmission electron microscopy (TEM), and UV-vis absorption spectra. In order to investigate the photophysical behaviours of these materials, the visible and NIR luminescent spectra and the energy transfer process have been systematically investigated. Moreover, efforts have been made to produce Eu- and Sm-based plastic attapulgite materials by utilizing poly(methyl methacrylate) (PMMA) matrices, and the dispersibility of the lanthanide-doped hybrids in PMMA provides them with a high mechanical strength. The lanthanide-doped attapulgite appears to be an interesting material for photophysical applications. The results of this work would have potential significance for the design and assembly of luminescent lanthanide materials for light-emitting diodes (LED), sunlight-conversion films, optical amplifiers, solar concentrators, and lasers.

  14. Crystallographic features of {alpha}``-martensite in titanium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ivasishin, O.M. [AN Ukrainskoj SSR, Kiev (Ukraine). Inst. Metallov Fiziki; Kosenko, N.S. [AN Ukrainskoj SSR, Kiev (Ukraine). Inst. Metallov Fiziki; Shevchenko, S.V. [AN Ukrainskoj SSR, Kiev (Ukraine). Inst. Metallov Fiziki

    1995-12-01

    Equilibrium volume fractions of twins ({alpha}{sub 0}) and habit plane orientation (anti n{sub 0}) of the orthorhombic {alpha}``-martensite in titanium alloys with {beta}-stabilizing elements were determined by minimization of the elastic strain energy. Calculations were made in the basis of one of the twinned domains. It was shown that these parameters are varying considerably depending on the solute element content. For Ti-Ta and Ti-Mo systems habit plane rotated from {l_brace}434{r_brace}{sub {beta}} to {l_brace}433{r_brace}{sub {beta}} pole and {alpha}{sub 0} grew with Ta (Mo) content increase. For Ti-20at%Ta {alpha}{sub 0} reached the value of 1, i.e. martensite plate became monodomain. For Ti-Mo system monodomain state was not achieved. For Ti-Nb system converse concentrational dependence of martensite parameters was obtained: {alpha}{sub 0} decreased with Nb content increase, and n showed a rotation from {l_brace}434{r_brace}{sub {beta}} pole in a direction opposite to that for Ti-Ta and Ti-Mo systems. (orig.).

  15. NANOG upregulates c-Jun oncogene expression through binding the c-Jun promoter.

    Science.gov (United States)

    Lin, Yanli; Xiong, Fuyin; Zhou, Yanrong; Wu, Xiaojie; Liu, Fang; Xue, Shiwei; Chen, Hongxing

    2015-11-01

    NANOG plays important roles in neoplastic processes. However, the molecular mechanism of NANOG in tumorigenesis remains to be elucidated. In this report, we demonstrated that forced expression of NANOG in 293 cells and cancer cells led to increased c-Jun expression, whereas downregulation of endogenous NANOG significantly reduced c-Jun expression in cancer cells. Dual luciferase reporter assays demonstrated that NANOG binds the c-Jun proximal promoter and transactivates the c-Jun gene. An ATTA consensus motif between the -160 and -268 region of the c-Jun promoter was identified as the NANOG-responsive element. Electromobility shift assay and chromatin immunoprecipitation results confirmed the direct binding of NANOG protein to the c-Jun promoter in vitro and in vivo. NANOG directly bound c-Jun protein as shown by GST pulldown and immunoprecipitation assays. Taking these findings together, we conclude that c-Jun is a direct target gene of NANOG and that c-Jun protein may be a novel co-activator of NANOG in cancer cells. We suggest the possibility that NANOG may play a significant role in carcinogenesis via its activation of c-Jun expression.

  16. 中日筷子习俗比较%Comparison of Chinese and Japanese Chopsticks Custom

    Institute of Scientific and Technical Information of China (English)

    顾玲玲

    2015-01-01

    Chopsticks are a kind of indispensable tableware in the daily life of Chinese and Japanese .China and Japan have always atta-ched great importance to the culture of chopsticks .This article attempts from three parts such as the origin of chopsticks , the etiquette and taboos of chopsticks , the use of chopsticks in the folklore to illustrate that the cultural exchanges between China and Japan has a long and extensive history and it is very important to protect and promote the culture of chopsticks .%筷子是中日两国人民日常生活中不可或缺的餐具,中国和日本历来都十分重视筷子文化。本文试图从筷子的起源、筷子的礼俗与禁忌、筷子在民俗中的运用三个方面,说明中日两国文化交流的悠久和广泛,以及保护和弘扬筷子文化的重要性。

  17. Characterization of spontaneous mutation in the oxyR strain of Escherichia coli.

    Science.gov (United States)

    Yamamura, E; Nunoshiba, T; Kawata, M; Yamamoto, K

    2000-12-20

    Escherichia coli K-12 strain EY5, deficient in oxyR, was constructed to assess the role of oxyR and oxyR-regulated regulon in spontaneous mutagenesis. Mutagenesis was monitored by selecting two forward mutations of colicin B-sensitive to resistance and valine-sensitive to resistance, one base substitution mutation of rifampicin-sensitive to resistance and one reversion of argE3 his-4 to Arg(+) His(+). Deficiency of oxyR did not lead to the enhancement of spontaneous mutation frequencies of the four markers tested. By DNA sequence analysis, we determined 49 colicin B-resistant mutants derived from EY5 and found that 37% were base substitutions, 29% IS element insertions, 20% deletions, and 14% single base frameshifts. Among the base substitutions, G:C-->T:A transversions predominated followed by G:C-->A:T transitions and A:T-->T:A transversions. These spectra were essentially the same as those from oxyR(+) strains. The results indicate that oxyR and oxyR-regulated genes do not play a significant role in the defense against spontaneous mutagenesis.

  18. Variation in genomic landscape of clear cell renal cell carcinoma across Europe.

    Science.gov (United States)

    Scelo, Ghislaine; Riazalhosseini, Yasser; Greger, Liliana; Letourneau, Louis; Gonzàlez-Porta, Mar; Wozniak, Magdalena B; Bourgey, Mathieu; Harnden, Patricia; Egevad, Lars; Jackson, Sharon M; Karimzadeh, Mehran; Arseneault, Madeleine; Lepage, Pierre; How-Kit, Alexandre; Daunay, Antoine; Renault, Victor; Blanché, Hélène; Tubacher, Emmanuel; Sehmoun, Jeremy; Viksna, Juris; Celms, Edgars; Opmanis, Martins; Zarins, Andris; Vasudev, Naveen S; Seywright, Morag; Abedi-Ardekani, Behnoush; Carreira, Christine; Selby, Peter J; Cartledge, Jon J; Byrnes, Graham; Zavadil, Jiri; Su, Jing; Holcatova, Ivana; Brisuda, Antonin; Zaridze, David; Moukeria, Anush; Foretova, Lenka; Navratilova, Marie; Mates, Dana; Jinga, Viorel; Artemov, Artem; Nedoluzhko, Artem; Mazur, Alexander; Rastorguev, Sergey; Boulygina, Eugenia; Heath, Simon; Gut, Marta; Bihoreau, Marie-Therese; Lechner, Doris; Foglio, Mario; Gut, Ivo G; Skryabin, Konstantin; Prokhortchouk, Egor; Cambon-Thomsen, Anne; Rung, Johan; Bourque, Guillaume; Brennan, Paul; Tost, Jörg; Banks, Rosamonde E; Brazma, Alvis; Lathrop, G Mark

    2014-10-29

    The incidence of renal cell carcinoma (RCC) is increasing worldwide, and its prevalence is particularly high in some parts of Central Europe. Here we undertake whole-genome and transcriptome sequencing of clear cell RCC (ccRCC), the most common form of the disease, in patients from four different European countries with contrasting disease incidence to explore the underlying genomic architecture of RCC. Our findings support previous reports on frequent aberrations in the epigenetic machinery and PI3K/mTOR signalling, and uncover novel pathways and genes affected by recurrent mutations and abnormal transcriptome patterns including focal adhesion, components of extracellular matrix (ECM) and genes encoding FAT cadherins. Furthermore, a large majority of patients from Romania have an unexpected high frequency of A:T>T:A transversions, consistent with exposure to aristolochic acid (AA). These results show that the processes underlying ccRCC tumorigenesis may vary in different populations and suggest that AA may be an important ccRCC carcinogen in Romania, a finding with major public health implications.

  19. Patterns of diversity and abundance of fungus-growing ants (Formicidae: Attini in areas of the Brazilian Cerrado Padrões de diversidade e abundância de formigas cultivadoras de fungo (Formicidade: Attini em áreas do Cerrado Brasileiro

    Directory of Open Access Journals (Sweden)

    Heraldo L. Vasconcelos

    2008-09-01

    Full Text Available Fungus-growing ants (tribe Attini are characteristic elements of the New World fauna. However, there is little information on the patterns of diversity, abundance, and distribution of attine species in their native ecosystems, especially for the so-called "lower" genera of the tribe. A survey of attine ant nests (excluding Atta Fabricus, 1804 and Acromyrmex Mayr, 1865 was conducted in a variety of savanna and forest habitats of the Cerrado biome near Uberlândia, Brazil. In total, 314 nests from 21 species of nine genera were found. Trachymyrmex Forel, 1893 was the most diverse genus with 10 species. Eighteen species were found in the savannas, including Mycetagroicus cerradensis Brandão & Mayhé-Nunes, 2001, a species from a recently-described genus of Attini, whereas in the forests only 12 species were found. Forest and savannas support relatively distinct faunas, each with a number of unique species; the species present in the forest habitats did not represent a nested subset of the species found in the savannas. Furthermore, although many species were common to both types of vegetation, their abundances were quite different. The density of attine nests is relatively high at some sites, exceeding an estimated 4,000 nests per hectare. In this sense, attine ants can be regarded as prevalent invertebrate taxa in the Brazilian Cerrado.As formigas cultivadoras de fungos (tribo Attini são exclusivas da fauna do Novo Mundo. Entretanto, existem poucas informações sobre os padrões de diversidade, abundância e distribuição das espécies de Attini em seus ecossistemas nativos, em especial para os gêneros menos derivados desta tribo. Um levantamento de ninhos de Attini (excluindo Atta Fabricius, 1804 e Acromyrmex Mayr, 1865 foi realizado em diversos ambientes savânicos e de floresta do bioma Cerrado próximos à Uberlândia, Brasil. Encontramos 314 ninhos de 21 espécies pertencentes a nove gêneros da tribo. Trachymyrmex Forel, 1893 foi o g

  20. Seasonality, age structure and reproduction of Leptodactylus (Lithodytes lineatus (Anura, Leptodactylidae in Rondônia state, southwestern Amazon, Brazil Sazonalidade, estrutura etária e reprodução de Leptodactylus (Lithodytes lineatus (Anura, Leptodactylidae no estado de Rondônia, Brasil

    Directory of Open Access Journals (Sweden)

    Paulo Sérgio Bernarde

    2009-12-01

    Full Text Available Leptodactylus(Lithodytes lineatus (Schneider, 1799 is an Amazonian leaf litter frog considered rare or uncommon in several studies on anuran communities. Despite being a widely distributed frog in Amazonian forests, knowledge of the biology and ecology of this species is relatively scarce. This species has been reported to live in association with leaf-cutter ant nests (Atta spp. during the breeding period. In this paper we present data on the seasonality of this species and some reproductive information gathered at a locality of Rondônia state, northwestern Brazil. Field work was carried out between April 2001 and March 2002, with the use of pitfall traps with drift fences as a survey method. Leptodactylus (L. lineatus had a higher capture frequency in this locality compared to that of other studies carried out in other Amazonian localities, possibly because this species has secretive habits, such as calling and breeding from nests of leaf-cutting ants, and are difficult to find during visual encounter surveys. The breeding period occurs between October and March. Calling males and egg-bearing females were found between September and February and juvenile recruitment occurred mainly from the end of the rainy season to the beginning of the dry season (February to June. Males and females show sexual dimorphism in SVL, females being significantly larger than males. The number of ovarian eggs per female varies from 110 to 328 and analyses indicate that there is a significant correlation with SVL.Leptodactylus(Lithodytes lineatus (Schneider, 1799 é uma espécie de anuro amazônico considerado raro ou incomum em diversos estudos de comunidades de anfíbios. Embora apresente ampla distribuição na Floresta Amazônica, conhecimento sobre a sua biologia e ecologia são escassos. Esta espécie tem sido relatada por viver em associação com ninhos de formigas cortadeiras (Atta spp. durante o período reprodutivo. Neste trabalho, nós apresentamos

  1. Probing into John Locke’ s Moral Education Thought%洛克德育思想探微

    Institute of Scientific and Technical Information of China (English)

    贺晴

    2014-01-01

    John Locke ’ s educational goal is training gentleman .In all kinds of target of the gentleman education , Locke atta-ched most importance to moral education .The content of Locke ’ s moral education mainly has three aspects that include strong char-acter, excellent quality and good manners .The principles of Locke ’ s moral education include principle of As Early As Possible , principle of development habit and teaching according to his ability .The methods of Locke ’s moral education include model educa-tion, the combination of reward and punishment and discussion .Limited in his era,there are some defects on Locke ’ s moral educa-tion thought .%洛克的教育目标是培养绅士,在绅士教育的各种目标中,洛克最为看重德育教育。洛克所主张的德育主要包含坚强的性格、优良的品格、良好的礼仪三方面内容。洛克进行德育教育主要遵循及早教育、培养习惯、因材施教原则,其方法主要有榜样教育、奖惩结合、说理等。同样,由于时代所限,洛克的德育思想也有一定缺陷。

  2. Pharmacoinformatics approach for investigation of alternative potential hepatitis C virus nonstructural protein 5B inhibitors

    Directory of Open Access Journals (Sweden)

    Mirza MU

    2015-03-01

    Full Text Available Muhammad Usman Mirza,1 Noor-Ul-Huda Ghori,2 Nazia Ikram,3 Abdur Rehman Adil,4 Sadia Manzoor3 1Centre for Research in Molecular Medicine (CRiMM, The University of Lahore, Lahore, 2Atta-ur-Rehman School of Applied Biosciences (ASAB, National University of Science and Technology, Islamabad, 3Institute of Molecular Biology and Biotechnology (IMBB, The University of Lahore, Lahore, Pakistan; 4Centre for Excellence in Molecular Biology (CEMB, The University of Punjab, Lahore, Pakistan Abstract: Hepatitis C virus (HCV is one of the major viruses affecting the world today. It is a highly variable virus, having a rapid reproduction and evolution rate. The variability of genomes is due to hasty replication catalyzed by nonstructural protein 5B (NS5B which is also a potential target site for the development of anti-HCV agents. Recently, the US Food and Drug Administration approved sofosbuvir as a novel oral NS5B inhibitor for the treatment of HCV. Unfortunately, it is much highlighted for its pricing issues. Hence, there is an urgent need to scrutinize alternate therapies against HCV that are available at affordable price and do not have associated side effects. Such a need is crucial especially in underdeveloped countries. The search for various new bioactive compounds from plants is a key part of pharmaceutical research. In the current study, we applied a pharmacoinformatics-based approach for the identification of active plant-derived compounds against NS5B. The results were compared to docking results of sofosbuvir. The lead compounds with high-binding ligands were further analyzed for pharmacokinetic and pharmacodynamic parameters based on in silico absorption, distribution, metabolism, excretion, and toxicity (ADMET profile. The results showed the potential alternative lead compounds that can be developed into commercial drugs having high binding energy and promising ADMET properties. Keywords: hepatitis C, NS5B inhibitors, molecular docking, Auto

  3. The prominent role of fungi and fungal enzymes in the ant-fungus biomass conversion symbiosis.

    Science.gov (United States)

    Lange, L; Grell, M N

    2014-06-01

    Molecular studies have added significantly to understanding of the role of fungi and fungal enzymes in the efficient biomass conversion, which takes place in the fungus garden of leaf-cutting ants. It is now clear that the fungal symbiont expresses the full spectrum of genes for degrading cellulose and other plant cell wall polysaccharides. Since the start of the genomics era, numerous interesting studies have especially focused on evolutionary, molecular, and organismal aspects of the biological and biochemical functions of the symbiosis between leaf-cutting ants (Atta spp. and Acromyrmex spp.) and their fungal symbiont Leucoagaricus gongylophorus. Macroscopic observations of the fungus-farming ant colony inherently depict the ants as the leading part of the symbiosis (the myrmicocentric approach, overshadowing the mycocentric aspects). However, at the molecular level, it is fungal enzymes that enable the ants to access the nutrition embedded in recalcitrant plant biomass. Our hypothesis is that the evolutionary events that established fungus-farming practice were predisposed by a fascinating fungal evolution toward increasing attractiveness to ants. This resulted in the ants allowing the fungus to grow in the nests and began to supply plant materials for more fungal growth. Molecular studies also confirm that specialized fungal structures, the gongylidia, with high levels of proteins and rich blend of enzymes, are essential for symbiosis. Harvested and used as ant feed, the gongylidia are the key factor for sustaining the highly complex leaf-cutting ant colony. This microbial upgrade of fresh leaves to protein-enriched animal feed can serve as inspiration for modern biorefinery technology.

  4. Identification and functional characterization of heat shock transcription factor1 in Litopenaeus vannamei.

    Science.gov (United States)

    Yan, Hui; Zhang, Shuang; Li, Xiao-Yun; Yuan, Feng-Hua; Qiu, Wei; Chen, Yong-Gui; Weng, Shao-Ping; He, Jian-Guo; Chen, Yi-Hong

    2014-03-01

    Heat shock transcription factors belong to the heat shock factor (HSF) protein family, which are involved in heat shock protein (HSP) gene regulation. They are critical for cell survival upon exposure to harmful conditions. In this study, we identified and characterized a HSF1 (LvHSF1) gene in Litopenaeus vannamei, with a full-length cDNA of 2841 bp and an open reading frame encoding a putative protein of 632 amino acids. Through multiple sequence alignment and phylogenetic analysis, it was revealed that LvHSF1 was closed to insect HSF family, which contained a highly conserved DNA-binding domain, oligomerization domains with HR-A/B, and a nuclear localization signal. Tissues distribution showed that LvHSF1 was widely expressed in all tissues tested. And it was upregulated in hemocytes and gills after Vibrio alginolyticus or Staphylococcus aureus infection. Dual-luciferase reporter assays indicated that LvHSF1 activated the promoters of L. vannamei HSP70 (LvHSP70) and L. vannamei Cactus (LvCactus), while inhibited the expressions of Drosophila antimicrobial peptide (AMP) Atta, Mtk, and L. vannamei AMP PEN4 through NF-κB signal transduction pathway modification. Knocked-down expression of LvHSF1 by dsRNA resulted in downregulations of LvHSP70 and LvCactus, as well as cumulative mortality decreasing under V. alginolyticus or S. aureus infection in L. vannamei. Taken together, our data strongly suggest that LvHSF1 is involved in LvHSP70 regulation, therefore plays a great role in stress resistance. And it also takes part in LvCactus/LvDorsal feedback regulatory pathway modification of L. vannamei, which is in favor of V. alginolyticus or S. aureus infection.

  5. In-situ studies on volatile jet exhaust particle emissions - impacts of fuel sulfur content and environmental conditions on nuclei-mode aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, F.; Baumann, R.; Petzold, A.; Busen, R.; Schulte, P.; Fiebig, M. [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Wessling (Germany). Inst. fuer Physik der Atmosphaere; Brock, C.A. [Denver Univ., CO (United States). Dept. of Engineering

    2000-02-01

    In-situ measurements of ultrafine aerosol particle emissions were performed at cruise altitudes behind the DLR ATTAS research jet (RR M45H M501 engines) and a B737-300 aircraft (CFM56-3B1 engines). Measurements were made 0.15-20 seconds after emission as the source aircraft burned fuel with sulfur contents (FSC) of 2.6, 56 or 118 mg kg{sup -1}. Particle size distributions of from 3 to 60 nm diameter were determined using CN-counters with varying lower size detection limits. Volatile particle concentrations in the aircraft plumes strongly increased as diameter decreased toward the sizes of large molecular clusters, illustrating that apparent particle emissions are extremely sensitive to the smallest particle size detectable by the instrument used. Environmental conditions and plume age alone could influence the number of detected ultrafine (volatile) aerosols within an order of magnitude, as well. The observed volatile particle emissions decreased nonlinearly as FSC decreased to 60 mg kg{sup -1}, reaching minimum values of about 2 x 10{sup 17} kg{sup -1} and 2 x 10{sup 16} kg{sup -1} for particles >3 nm and >5 nm, respectively. Volatile particle emissions did not change significantly as FSCs were further reduced below 60 mg kg{sup -1}. Volatile particle emissions did not differ significantly between the two studied engine types. In contrast, soot particle emissions from the modern CFM56-3B1 engines were 4-5 times less (4 x 10{sup 14} kg{sup -1}) than from the older RR M45H M501 engines (1.8 x 10{sup 15} kg{sup -1}). Contrail processing has been identified as an efficient sink/quenching parameter for ultrafine particles and reduces the remaining interstitial aerosol by factors 2-10 depending on particle size.

  6. Especies promisorias para el ecoturismo en “Campo Aventura Roca Madre”, Toluviejo-Sucre, Colombia

    Directory of Open Access Journals (Sweden)

    Alcides Sampedro-M

    2013-03-01

    Full Text Available Objetivo. Determinar las especies de flora y fauna más importantes para el desarrollo del ecoturismo, en una localidad del departamento de Sucre, Colombia. Materiales y métodos. Se hizo un listado de las especies de flora y fauna observadas en el sendero ecológico de un centro de ecoturismo en Toluviejo, Sucre y se calculó su abundancia, importancia económica, estado de conservación y adaptaciones, que fueron evaluadas mediante un índice de importancia potencial para el ecoturismo, que suma los valores que se asignan a las variables consideradas de interés. Resultados. Se detectaron 18 especies promisorias de fauna, de 91 especies observadas y 16 especies vegetales de 53 observadas. Los animales de mayor potencial ecoturístico resultantes, fueron: Dendrobates truncatus y Saguinus oedipus, especies endémicas de Colombia, seguidas por Basiliscus basiliscus, Atta sp., Morpho peleides, Lycorea halia y Ara ararauna; todas estas con una alta abundancia y fácil detección. Dentro de las plantas, Anacardium excelsum obtuvo el mayor índice de importancia, como resultado de su endemismo y sus adaptaciones. Las especies Piper auritum, Matayba escrobiculata, Tabernaemontana cymosa y la comúnmente conocida como jazmín de monte, fueron fácilmente detectables y abundantes, además Brownea ariza y Tabebuia rosea resultaron las más representativas por la belleza de sus flores. Conclusiones. Se determinaron las especies que pueden ser de interés para los ecoturistas y esto hace posible mejorar el producto que se oferta a partir de profundizar en su conocimiento.

  7. Enrichment and Broad Representation of Plant Biomass-Degrading Enzymes in the Specialized Hyphal Swellings of Leucoagaricus gongylophorus, the Fungal Symbiont of Leaf-Cutter Ants.

    Science.gov (United States)

    Aylward, Frank O; Khadempour, Lily; Tremmel, Daniel M; McDonald, Bradon R; Nicora, Carrie D; Wu, Si; Moore, Ronald J; Orton, Daniel J; Monroe, Matthew E; Piehowski, Paul D; Purvine, Samuel O; Smith, Richard D; Lipton, Mary S; Burnum-Johnson, Kristin E; Currie, Cameron R

    2015-01-01

    Leaf-cutter ants are prolific and conspicuous constituents of Neotropical ecosystems that derive energy from specialized fungus gardens they cultivate using prodigious amounts of foliar biomass. The basidiomycetous cultivar of the ants, Leucoagaricus gongylophorus, produces specialized hyphal swellings called gongylidia that serve as the primary food source of ant colonies. Gongylidia also contain plant biomass-degrading enzymes that become concentrated in ant digestive tracts and are deposited within fecal droplets onto fresh foliar material as ants incorporate it into the fungus garden. Although the enzymes concentrated by L. gongylophorus within gongylidia are thought to be critical to the initial degradation of plant biomass, only a few enzymes present in these hyphal swellings have been identified. Here we use proteomic methods to identify proteins present in the gongylidia of three Atta cephalotes colonies. Our results demonstrate that a diverse but consistent set of enzymes is present in gongylidia, including numerous plant biomass-degrading enzymes likely involved in the degradation of polysaccharides, plant toxins, and proteins. Overall, gongylidia contained over three quarters of all biomass-degrading enzymes identified in the L. gongylophorus genome, demonstrating that the majority of the enzymes produced by this fungus for biomass breakdown are ingested by the ants. We also identify a set of 40 of these enzymes enriched in gongylidia compared to whole fungus garden samples, suggesting that certain enzymes may be particularly important in the initial degradation of foliar material. Our work sheds light on the complex interplay between leaf-cutter ants and their fungal symbiont that allows for the host insects to occupy an herbivorous niche by indirectly deriving energy from plant biomass.

  8. Genome Analysis of Two Pseudonocardia Phylotypes Associated with Acromyrmex Leafcutter Ants Reveals Their Biosynthetic Potential.

    Science.gov (United States)

    Holmes, Neil A; Innocent, Tabitha M; Heine, Daniel; Bassam, Mahmoud Al; Worsley, Sarah F; Trottmann, Felix; Patrick, Elaine H; Yu, Douglas W; Murrell, J C; Schiøtt, Morten; Wilkinson, Barrie; Boomsma, Jacobus J; Hutchings, Matthew I

    2016-01-01

    The attine ants of South and Central America are ancient farmers, having evolved a symbiosis with a fungal food crop >50 million years ago. The most evolutionarily derived attines are the Atta and Acromyrmex leafcutter ants, which harvest fresh leaves to feed their fungus. Acromyrmex and many other attines vertically transmit a mutualistic strain of Pseudonocardia and use antifungal compounds made by these bacteria to protect their fungal partner against co-evolved fungal pathogens of the genus Escovopsis. Pseudonocardia mutualists associated with the attines Apterostigma dentigerum and Trachymyrmex cornetzi make novel cyclic depsipeptide compounds called gerumycins, while a mutualist strain isolated from derived Acromyrmex octospinosus makes an unusual polyene antifungal called nystatin P1. The novelty of these antimicrobials suggests there is merit in exploring secondary metabolites of Pseudonocardia on a genome-wide scale. Here, we report a genomic analysis of the Pseudonocardia phylotypes Ps1 and Ps2 that are consistently associated with Acromyrmex ants collected in Gamboa, Panama. These were previously distinguished solely on the basis of 16S rRNA gene sequencing but genome sequencing of five Ps1 and five Ps2 strains revealed that the phylotypes are distinct species and each encodes between 11 and 15 secondary metabolite biosynthetic gene clusters (BGCs). There are signature BGCs for Ps1 and Ps2 strains and some that are conserved in both. Ps1 strains all contain BGCs encoding nystatin P1-like antifungals, while the Ps2 strains encode novel nystatin-like molecules. Strains show variations in the arrangement of these BGCs that resemble those seen in gerumycin gene clusters. Genome analyses and invasion assays support our hypothesis that vertically transmitted Ps1 and Ps2 strains have antibacterial activity that could help shape the cuticular microbiome. Thus, our work defines the Pseudonocardia species associated with Acromyrmex ants and supports the hypothesis

  9. Effects of dating errors on nonparametric trend analyses of speleothem time series

    Directory of Open Access Journals (Sweden)

    M. Mudelsee

    2012-10-01

    Full Text Available A fundamental problem in paleoclimatology is to take fully into account the various error sources when examining proxy records with quantitative methods of statistical time series analysis. Records from dated climate archives such as speleothems add extra uncertainty from the age determination to the other sources that consist in measurement and proxy errors. This paper examines three stalagmite time series of oxygen isotopic composition (δ18O from two caves in western Germany, the series AH-1 from the Atta Cave and the series Bu1 and Bu4 from the Bunker Cave. These records carry regional information about past changes in winter precipitation and temperature. U/Th and radiocarbon dating reveals that they cover the later part of the Holocene, the past 8.6 thousand years (ka. We analyse centennial- to millennial-scale climate trends by means of nonparametric Gasser–Müller kernel regression. Error bands around fitted trend curves are determined by combining (1 block bootstrap resampling to preserve noise properties (shape, autocorrelation of the δ18O residuals and (2 timescale simulations (models StalAge and iscam. The timescale error influences on centennial- to millennial-scale trend estimation are not excessively large. We find a "mid-Holocene climate double-swing", from warm to cold to warm winter conditions (6.5 ka to 6.0 ka to 5.1 ka, with warm–cold amplitudes of around 0.5‰ δ18O; this finding is documented by all three records with high confidence. We also quantify the Medieval Warm Period (MWP, the Little Ice Age (LIA and the current warmth. Our analyses cannot unequivocally support the conclusion that current regional winter climate is warmer than that during the MWP.

  10. Deep Metamorphic Rock Series of Bayan Wula-mountain Granite-greenstone Belt and Gold MineralizationMA Runze%巴彦乌拉山深变质岩系的花岗-绿岩带与金成矿

    Institute of Scientific and Technical Information of China (English)

    胡晰; 马润则; 陈志耕; 张腊梅; 陈娟; 刘颖倩

    2015-01-01

    A large area of Archean granite - greenstone belt exposed in Bayan wula-mountain, which bedrock outcrops good. Survey area′greenstone belt is existing as the green schist facies of tectonic schist. At present, domestic and foreign atta-ches great importance to the study of granite greenstone belt, The major reason is that research on it has mineral and geological sig-nificance. However, Gold directly affecting the financial securi-ty of the country as a precious metal, which is very important for the national economy stability. Granite - greenstone belt has a close relation with gold deposit. At present, China 's most im-portant gold producing type is greenstone type gold deposit.%巴彦乌拉山出露大面积的太古代花岗-绿岩带,基岩出露良好。本区的绿岩带是以变质程度为绿片相的构造片岩形式出现的。国内外对花岗绿岩带的研究非常重视,主要是因为其研究对矿产和地质都具有重大意义。然而金为直接影响国家金融安全的贵重金属,对于国家的经济稳定有极其重要的作用。其中花岗-绿岩带与金成矿有着密切关系。目前我国主要的产金类型为绿岩型金矿。

  11. Mesenchymal stem cell therapy for osteoarthritis: current perspectives

    Directory of Open Access Journals (Sweden)

    Wyles CC

    2015-08-01

    Full Text Available Cody C Wyles,1 Matthew T Houdek,2 Atta Behfar,3 Rafael J Sierra,21Mayo Medical School, 2Department of Orthopedic Surgery, 3Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USAAbstract: Osteoarthritis (OA is a painful chronic condition with a significant impact on quality of life. The societal burden imposed by OA is increasing in parallel with the aging population; however, no therapies have demonstrated efficacy in preventing the progression of this degenerative joint disease. Current mainstays of therapy include activity modification, conservative pain management strategies, weight loss, and if necessary, replacement of the affected joint. Mesenchymal stem cells (MSCs are a multipotent endogenous population of progenitors capable of differentiation to musculoskeletal tissues. MSCs have a well-documented immunomodulatory role, managing the inflammatory response primarily through paracrine signaling. Given these properties, MSCs have been proposed as a potential regenerative cell therapy source for patients with OA. Research efforts are focused on determining the ideal source for derivation, as MSCs are native to several tissues. Furthermore, optimizing the mode of delivery remains a challenge both for appropriate localization of MSCs and for directed guidance toward stemming the local inflammatory process and initiating a regenerative response. Scaffolds and matrices with growth factor adjuvants may prove critical in this effort. The purpose of this review is to summarize the current state of MSC-based therapeutics for OA and discuss potential barriers that must be overcome for successful implementation of cell-based therapy as a routine treatment strategy in orthopedics.Keywords: mesenchymal stem cell, osteoarthritis, treatment, regenerative medicine, cell therapy

  12. Comportamento espectral de materiais de solos e de estruturas biogênicas associadas

    Directory of Open Access Journals (Sweden)

    J. A. M. Demattê

    1998-12-01

    Full Text Available No presente estudo, verificou-se a interferência da macrofauna edáfica sobre os atributos físicos e químicos e sua relação com a reflectância espectral de um Latossolo Vermelho-Amarelo (LV, Terra Roxa Estruturada latossólica (TR e Vertissolo (V. Esses solos localizam-se em três pontos ao longo de uma toposseqüência da região de Piracicaba (SP. As amostras foram direcionadas para os agregados formados pelas formigas cortadeiras (Atta sp., cupins (Cornitermes cumulans e minhocas (Pontoscolex corethrurus, os quais foram comparados com o solo-controle sem atividade visível e recente dos animais (testemunha. Foram avaliadas a granulometria e a composição química das amostras de solo. O comportamento espectral do solo foi obtido em laboratório, utilizando espectroradiômetro entre 400 e 2.500 nm. Os coprólitos de minhoca apresentaram 2 a 3 vezes mais fósforo e um incremento de 30 a 50% na matéria orgânica em relação ao horizonte superficial do solo. Os agregados de cupins e formigas apresentaram composição química semelhante à dos horizontes subsuperficiais dos solos. O comportamento espectral dos agregados biológicos variou conforme sua composição química e profundidade de ação dos animais. No caso da minhoca, as curvas de reflectância foram semelhantes às do horizonte superficial para os três solos. Para as estruturas de cupim e formiga, tanto a composição química como o comportamento espectral corresponderam ao horizonte subsuperficial no LV e TR.

  13. Krypton-81 in groundwater of the Culebra Dolomite near the Waste Isolation Pilot Plant, New Mexico.

    Science.gov (United States)

    Sturchio, Neil C; Kuhlman, Kristopher L; Yokochi, Reika; Probst, Peter C; Jiang, Wei; Lu, Zheng-Tian; Mueller, Peter; Yang, Guo-Min

    2014-05-01

    The Waste Isolation Pilot Plant (WIPP) in New Mexico is the first geologic repository for disposal of transuranic nuclear waste from defense-related programs of the US Department of Energy. It is constructed within halite beds of the Permian-age Salado Formation. The Culebra Dolomite, confined within Rustler Formation evaporites overlying the Salado Formation, is a potential pathway for radionuclide transport from the repository to the accessible environment in the human-disturbed repository scenario. Although extensive subsurface characterization and numerical flow modeling of groundwater has been done in the vicinity of the WIPP, few studies have used natural isotopic tracers to validate the flow models and to better understand solute transport at this site. The advent of Atom-Trap Trace Analysis (ATTA) has enabled routine measurement of cosmogenic (81)Kr (half-life 229,000 yr), a near-ideal tracer for long-term groundwater transport. We measured (81)Kr in saline groundwater sampled from two Culebra Dolomite monitoring wells near the WIPP site, and compared (81)Kr model ages with reverse particle-tracking results of well-calibrated flow models. The (81)Kr model ages are ~130,000 and ~330,000 yr for high-transmissivity and low-transmissivity portions of the formation, respectively. Compared with flow model results which indicate a relatively young mean hydraulic age (~32,000 yr), the (81)Kr model ages imply substantial physical attenuation of conservative solutes in the Culebra Dolomite and provide limits on the effective diffusivity of contaminants into the confining aquitards.

  14. Mutational spectra of Salmonella typhimurium revertants induced by chlorohydroxyfuranones, byproducts of chlorine disinfection of drinking water.

    Science.gov (United States)

    Knasmüller, S; Zöhrer, E; Kronberg, L; Kundi, M; Franzén, R; Schulte-Hermann, R

    1996-03-01

    The base substitution specificities of 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), 3-chloro-4-(chloromethyl)-5-hydroxy-2(5H)-furanone (CMCF), 3,4-dichloro-5-hydroxy-2(5H)-furanone (MCA), and chloromalonaldehyde (CMA), a putative breakdown product of MCA, were examined in the hisG46 gene and in the hisG428 gene of Salmonella typhimurium using allele specific oligonucleotide hybridization. Although the compounds are structurally closely related, they induced substantially different mutation spectra: MCA and CMA caused primarily GC-->AT transitions in the hisG46 allele (target sequence CCC), in particular, at the second position of the codon in strain TA100. In TA100 the mutation spectrum of MCA was similar to that of CMA. The mutational specificity of MCA can be explained as a consequence of misincorporation opposite to cyclic etheno adducts identical to those formed by the carcinogen vinyl chloride. The spectra induced by MX and CMCF in TA100 were almost identical but distinctively different from the spectra of MCA and CMA. Both compounds induced primarily GC-->TA transversions, in particular, at the second position of the codon, and to a lesser extent in the first position of the codon. An identical site bias is induced by carcinogens such as polycyclic aromatic hydrocarbons and heterocyclic amines as a consequence of formation of (noncyclic) guanosine adducts. In hisG428 (target sequence TAA) MX induced again primarily GC-->TA transversions in Tyr tRNA genes (supC/M) and, to a lesser extent, intragenic AT-->TA transversions (TAA-->AAA). The possible involvement of guanosine and adenosine adducts in the mutational specificity of MX is addressed.

  15. Bio-Engineering tissue and V.A.C. therapy: A new method for the treatment of extensive necrotizing infection in the diabetic foot.

    Science.gov (United States)

    Armenio, Andrea; Cutrignelli, Daniela Anna; Nardulli, Maria Luisa; Maggio, Giulio; Memeo, Giuseppe; De Santis, Valerio; Giudice, Giuseppe; Ressa, Cosmo Maurizio

    2016-12-06

    La prevalenza mondiale del diabete nel 2000 è stata stimata essere del 2.8% con una previsione del 4.4% nel 2030. A causa della neuropatia e dei processi ischemici che ne derivano, i pazienti diabetici sono purtroppo predisposti all’insorgenza di infezioni a carico del piede con un rischio di amputazione molto elevato. A tal proposito, un trattamento rapido ed efficace del processo necrotizzante impedirebbe complicanze maggiori e la stessa amputazione. Il nostro studio consiste in un’analisi retrospettiva condotta su 20 pazienti atta a valutare l’efficacia del sostituto dermico autologo bioingegnerizzato (Hyalograft 3D Autograft) in associazione alla V.A.C (vacuum assisted closure) Therapy per il trattamento delle ulcere diabetiche, rispetto ai metodi sinora impiegati. I pazienti selezionati, a seconda del trattamento eseguito, sono stati suddivisi in due gruppi omogenei di dieci pazienti ciascuno. Il gruppo controllo è stato trattato con il metodo standard, ovvero con debridment chirurgico e innesti cutanei autologhi, mentre il gruppo studio è stato trattato con il metodo in analisi. La raccolta dei dati ha suggerito come l’impiego combinato del sostituto dermico bioingegnerizzato e della pressione negativa determini, rispetto al gruppo controllo, un aumento della percentuale di guarigione, una riduzione del tasso di recidiva di lesioni anche estese e una maggiore ripresa della deambulazione autonoma. In conclusione, la nostra analisi ha evidenziato un metodo sicuro, affidabile e competitivo per il trattamento di ampie lesioni necrotizzanti del piede diabetico. Anche se ulteriori valutazioni sono necessarie, crediamo fortemente che l’associazione del derma bioingegnerizzato e della pressione negativa possa condurre ad una rapida ed efficace guarigione delle ulcere, migliorando la qualità della vita del paziente diabetico.

  16. Discovery of protein complexes with core-attachment structures from Tandem Affinity Purification (TAP) data.

    Science.gov (United States)

    Wu, Min; Li, Xiao-Li; Kwoh, Chee-Keong; Ng, See-Kiong; Wong, Limsoon

    2012-09-01

    Many cellular functions involve protein complexes that are formed by multiple interacting proteins. Tandem Affinity Purification (TAP) is a popular experimental method for detecting such multi-protein interactions. However, current computational methods that predict protein complexes from TAP data require converting the co-complex relationships in TAP data into binary interactions. The resulting pairwise protein-protein interaction (PPI) network is then mined for densely connected regions that are identified as putative protein complexes. Converting the TAP data into PPI data not only introduces errors but also loses useful information about the underlying multi-protein relationships that can be exploited to detect the internal organization (i.e., core-attachment structures) of protein complexes. In this article, we propose a method called CACHET that detects protein complexes with Core-AttaCHment structures directly from bipartitETAP data. CACHET models the TAP data as a bipartite graph in which the two vertex sets are the baits and the preys, respectively. The edges between the two vertex sets represent bait-prey relationships. CACHET first focuses on detecting high-quality protein-complex cores from the bipartite graph. To minimize the effects of false positive interactions, the bait-prey relationships are indexed with reliability scores. Only non-redundant, reliable bicliques computed from the TAP bipartite graph are regarded as protein-complex cores. CACHET constructs protein complexes by including attachment proteins into the cores. We applied CACHET on large-scale TAP datasets and found that CACHET outperformed existing methods in terms of prediction accuracy (i.e., F-measure and functional homogeneity of predicted complexes). In addition, the protein complexes predicted by CACHET are equipped with core-attachment structures that provide useful biological insights into the inherent functional organization of protein complexes. Our supplementary material can

  17. Glycyrrhetinic acid and E.resveratroloside act as potential plant derived compounds against dopamine receptor D3 for Parkinson’s disease: a pharmacoinformatics study

    Directory of Open Access Journals (Sweden)

    Mirza MU

    2014-12-01

    Full Text Available Muhammad Usman Mirza,1 A Hammad Mirza,2 Noor-Ul-Huda Ghori,3 Saba Ferdous4 1Centre for Research in Molecular Medicine, The University of Lahore, Lahore, Pakistan; 2Department of Bioscience, COMSATS Institute of Information Technology, Sahiwal, Pakistan; 3Atta-ur-Rehman School of Applied Biosciences, National University of Science and Technology, Islamabad, Pakistan; 4Institute of Structural and Molecular Biology, University College London, UK Abstract: Parkinson’s disease (PD is caused by loss in nigrostriatal dopaminergic neurons and is ranked as the second most common neurodegenerative disorder. Dopamine receptor D3 is considered as a potential target in drug development against PD because of its lesser side effects and higher degree of neuro-protection. One of the prominent therapies currently available for PD is the use of dopamine agonists which mimic the natural action of dopamine in the brain and stimulate dopamine receptors directly. Unfortunately, use of these pharmacological therapies such as bromocriptine, apomorphine, and ropinirole provides only temporary relief of the disease symptoms and is frequently linked with insomnia, anxiety, depression, and agitation. Thus, there is a need for an alternative treatment that not only hinders neurodegeneration, but also has few or no side effects. Since the past decade, much attention has been given to exploitation of phytochemicals and their use in alternative medicine research. This is because plants are a cheap, indispensable, and never ending resource of active compounds that are beneficial against various diseases. In the current study, 40 active phytochemicals against PD were selected through literature survey. These ligands were docked with dopamine receptor D3 using AutoDock and AutoDockVina. Binding energies were compared to docking results of drugs approved by the US Food and Drug Administration against PD. The compounds were further analyzed for their absorption, distribution

  18. Kidney function and mortality post-liver transplant in the Model for End-Stage Liver Disease era

    Directory of Open Access Journals (Sweden)

    Sethi A

    2011-11-01

    Full Text Available Aastha Sethi1, Michelle M Estrella1, Richard Ugarte2, Mohamed G Atta1 1Johns Hopkins University School of Medicine, Department of Medicine, Baltimore, MD, USA; 2University of Maryland Medical Center, Department of Medicine, Baltimore, MD, USA Abstract: The Model for End-Stage Liver Disease (MELD score incorporates serum creatinine and was introduced to facilitate allocation of orthotopic liver transplantation (LT. The objective is to determine the impact of MELD and kidney function on all-cause mortality. Among LTs performed in a tertiary referral hospital between 1995 and 2009, 419 cases were studied. Cox proportional hazards models were constructed to estimate the hazard ratios (HR and 95% confidence intervals (CI for death. Over mean follow-ups of 8.4 and 3.1 years during the pre-MELD and MELD era, 57 and 63 deaths were observed, respectively. Those transplanted during the MELD era had a higher likelihood of hepatorenal syndrome (8% vs 2%, P < 0.01, lower kidney function (median estimated glomerular filtration rate [eGFR] 77.8 vs 92.6 mL/min/1.73 m2, P < 0.01, and more pretransplantation renal replacement therapy (RRT (5% vs 1%; P < 0.01. All-cause mortality risk was similar in the MELD vs the pre-MELD era (HR: 0.98, 95% CI: 0.58–1.65. The risk of death, however, was nearly 3-fold greater (95% CI: 1.14–6.60 among those requiring pre-transplant RRT. Similarly, eGFR < 60 mL/min/1.73 m2 post-transplant was associated with a 2.5-fold higher mortality (95% CI: 1.48–4.11. The study suggests that MELD implementation had no impact on all-cause mortality post-LT. However, the need for pre-transplant RRT and post-transplant kidney dysfunction was associated with a more than 2-fold greater risk of subsequent death. Keywords: eGFR, mortality, MELD, liver transplant

  19. An overview of the Phalaenopsis orchid genome through BAC end sequence analysis

    Directory of Open Access Journals (Sweden)

    Hsiao Yu-Yun

    2011-01-01

    Full Text Available Abstract Background Phalaenopsis orchids are popular floral crops, and development of new cultivars is economically important to floricultural industries worldwide. Analysis of orchid genes could facilitate orchid improvement. Bacterial artificial chromosome (BAC end sequences (BESs can provide the first glimpses into the sequence composition of a novel genome and can yield molecular markers for use in genetic mapping and breeding. Results We used two BAC libraries (constructed using the BamHI and HindIII restriction enzymes of Phalaenopsis equestris to generate pair-end sequences from 2,920 BAC clones (71.4% and 28.6% from the BamHI and HindIII libraries, respectively, at a success rate of 95.7%. A total of 5,535 BESs were generated, representing 4.5 Mb, or about 0.3% of the Phalaenopsis genome. The trimmed sequences ranged from 123 to 1,397 base pairs (bp in size, with an average edited read length of 821 bp. When these BESs were subjected to sequence homology searches, it was found that 641 (11.6% were predicted to represent protein-encoding regions, whereas 1,272 (23.0% contained repetitive DNA. Most of the repetitive DNA sequences were gypsy- and copia-like retrotransposons (41.9% and 12.8%, respectively, whereas only 10.8% were DNA transposons. Further, 950 potential simple sequence repeats (SSRs were discovered. Dinucleotides were the most abundant repeat motifs; AT/TA dimer repeats were the most frequent SSRs, representing 253 (26.6% of all identified SSRs. Microsynteny analysis revealed that more BESs mapped to the whole-genome sequences of poplar than to those of grape or Arabidopsis, and even fewer mapped to the rice genome. This work will facilitate analysis of the Phalaenopsis genome, and will help clarify similarities and differences in genome composition between orchids and other plant species. Conclusion Using BES analysis, we obtained an overview of the Phalaenopsis genome in terms of gene abundance, the presence of repetitive

  20. Nursing human resource allocation status and development countermeasure in psychiatric department%精神科护理人力资源配置现状与发展对策

    Institute of Scientific and Technical Information of China (English)

    邱吉玲; 钟静

    2011-01-01

    目的:了解精神科护理人力资源配置现状,为加强护理人力资源管理提供借鉴.方法:对我院所有护理人员基本情况及2009年1~12月各临床护理单元护理人力资源配置、床位使用率、床护比的情况进行调查分析.结果:临床在岗护理人员短缺,床护比例失调;高学历、高职称人员缺乏;护理人员闲置的消耗性与临床的需求性相矛盾.结论:护理人力资源配置不足将导致护士身心耗竭,影响护理质量,使安全隐患的风险加剧.因此,应重视护士合理配置,用发展与求实的观点,核定护理工作量,增加护士编制,建立符合精神专科特点的床护比,从而提高精神科护理人力资源配置的有效性、科学性与合理性.%Objective:To know the status quo of psychiatric nursing human resource allocation and provide reference for human resource management. Methods: To survey and analyze the basic information of all the staff as well as human resource allocation of every nursing unit,the utilization rate for the bed and the proportion of nurses with bed during January to December 2009. Results:Lack of clinic nursing staff imbalance between nurses and bed short of well -educated and high title staff contradiction of idle caring nurses with the one needed. Conclusion:The insufficient human resource allocation will cause serious consequerce,such as the burnout of the nurse,thus have bad impact on the nursing quality,and to increase the safe risk, therefore we should pay more atta-tion to the nursing and rehabilitation by the development and realistic point of view add the official appraise criterion. Establish the reasonable rate between nurses and bed in conformity with psychiatry,thereby enhance the efficiency,Science and rationality of the psychiatric human resource allocation.

  1. DMB-375S电机轴螺旋键槽铣胎的改进设计%Improved Design of Double Sprial Keyways Milling Attachment of Type DMB-375S Motor Shaft

    Institute of Scientific and Technical Information of China (English)

    冯革

    2001-01-01

    DMB-375S电机轴铁芯键槽为大导程双螺旋键槽。在立式铣床上使用靠模胎具加工。胎具存在刚性差、精度低、操作不便的问题。为了提高加工精度和生产效率,对原胎具进行改进设计,采用挂轮进给、分度头旋转的运动方式进行铣削。分析FW160型分度头的传动系统图,得出分度头的定数取决于1:40的蜗轮传动,其它的均为1:1传动,如将1:1的螺旋齿轮传动改为蜗轮蜗杆传动即可大大提高分度头的定数,从而实现大导程螺旋键槽的加工。该胎具具有刚性好、精度高、操作简便的优点,选择适当的挂轮还可扩展其加工范围。%The keyways of the motor shaft of type DMB- 375S are two longpitch spir al slots.They are produced with profiling attachment in vertical miller.But the atta chment has some problems such as poor rigidity,low precision and hard to be used. For improving working precision and efficiency,The original attachment was redesigned, cutting with gear feed and graduator rot ation. According to the c alculating result of gears rate,this method is available since its few t ransmission links and compact structure.Analysing the transmission system drawwi ng of type FW160 graduator, we can easily know that its rate is depends on worm ge ars ra te 1:40,and other's is 1:1.If the helix gears with rate 1:1 can be changed to wo rm g ears,the rate of graduator will be increased greatly.So the long pitch keyways c an be worked out.The attachment designed in this new method has good rigidity, high precision, an d is easy to be operated. If to use the suitable gear change, its working range can be expanded.

  2. Metodología para la evaluación del potencial insecticida de especies forestales.

    Directory of Open Access Journals (Sweden)

    Morales Soto León

    2000-06-01

    Full Text Available La diversidad florística de Colombia plantea enormes retos de investigación, con miras a una utilización racional e integral de sus recursos forestales. Las plantas con efectos biocidas utilizables en el control de plagas o enfermedades revisten una singular importancia. El objetivo de este trabajo es plantear una metodología de fácil aplicación, bajo costo y rápidos resultados, que permita acopiar la información necesaria sobre el mayor número de especies con potencial en este sentido. La metodología plantea la siguiente secuencia: selección de las especies vegetales de interés, apoyada en los reportes bibliográficos, conocimiento ancestral y observaciones personales; recolección del material en el campo; preparación del extracto total a partir del material seco; pruebas iniciales con Artemia salina Lech. para detectar actividad biológica, a través de la determinación de la LC50 (las especies con LC50 menores de 1000 ppm se consideran promisorias y ameritan procesos posteriores de fraccionamiento químico, bioensayos con las sustancias más promisorias sobre algún organismo de interés particular y determinación final de los compuestos activos en la planta. La metodología descrita fue empleada en la evaluación del potencial de acción biocida de 5 especies arbóreas o arbustivas, Guarea guidonia (L. Sleumer y Trichia hirta L. (Meliaceae, Machaerium moritzianum Benth. (Fabaceae, Swinglea glutinosa Merrill. (Rutaceae y Mammea americana L. (Clusiaceae. Se utilizó para los bioensayos iniciales el microcrustáceo Artemia salina Leach como indicador del potencial biocida con el fin de seleccionar las dos especies más promisorias a partir de las LC50 obtenidas. Con las dos se realizaron los bioensayos para evaluar la acción fagoinhibidora en la hormiga arriera Atta cephalotes (L., y el posible control de Alconeura sp. (Homoptera: Cicadellidae, insecto chupador que afecta la ceiba verde Pseudobombax septenatum (Jacq. Dugand

  3. A novel educational tool for teaching ocular ultrasound

    Directory of Open Access Journals (Sweden)

    Mustafa MS

    2011-06-01

    Full Text Available MS Mustafa1, J Montgomery2, HR Atta11Department of Ophthalmology, Aberdeen Royal Infirmary, UK; 2Medi-CAL, College of Life Sciences and Medicine, University of Aberdeen, Foresterhill, Aberdeen, UKAbstract: Ocular ultrasound is now in increasing demand in routine ophthalmic clinical practice not only because it is noninvasive but also because of ever-advancing technology providing higher resolution imaging. It is however a difficult branch of ophthalmic investigations to grasp, as it requires a high skill level to interface with the technology and provide accurate interpretation of images for ophthalmic diagnosis and management. It is even more labor intensive to teach ocular ultrasound to another fellow clinician. One of the fundamental skills that proved difficult to learn and teach is the need for the examiner to “mentally convert” 2-dimensional B-scan images into 3-dimensional (3D interpretations. An additional challenge is the requirement to carry out this task in real time. We have developed a novel approach to teach ocular ultrasound by using a novel 3D ocular model. A 3D virtual model is built using widely available, open source, software. The model is then used to generate movie clips simulating different movements and orientations of the scanner head. Using Blender, Quicktime motion clips are choreographed and collated into interactive quizzes and other pertinent pedagogical media. The process involves scripting motion vectors, rotation, and tracking of both the virtual stereo camera and the model. The resulting sequence is then rendered for twinned right- and left-eye views. Finally, the twinned views are synchronized and combined in a format compatible with the stereo projection apparatus. This new model will help the student with spatial awareness and allow for assimilation of this awareness into clinical practice. It will also help with grasping the nomenclature used in ocular ultrasound as well as helping with localization of

  4. Genetic linkage maps for Asian and American lotus constructed using novel SSR markers derived from the genome of sequenced cultivar

    Directory of Open Access Journals (Sweden)

    Yang Mei

    2012-11-01

    Full Text Available Abstract Background The genus Nelumbo Adans. comprises two living species, N. nucifera Gaertan. (Asian lotus and N. lutea Pers. (American lotus. A genetic linkage map is an essential resource for plant genetic studies and crop improvement but has not been generated for Nelumbo. We aimed to develop genomic simple sequence repeat (SSR markers from the genome sequence and construct two genetic maps for Nelumbo to assist genome assembly and integration of a genetic map with the genome sequence. Results A total of 86,089 SSR motifs were identified from the genome sequences. Di- and tri-nucleotide repeat motifs were the most abundant, and accounted for 60.73% and 31.66% of all SSRs, respectively. AG/GA repeats constituted 51.17% of dinucleotide repeat motifs, followed by AT/TA (44.29%. Of 500 SSR primers tested, 386 (77.20% produced scorable alleles with an average of 2.59 per primer, and 185 (37.00% showed polymorphism among two parental genotypes, N. nucifera ‘Chinese Antique’ and N. lutea ‘AL1’, and six progenies of their F1 population. The normally segregating markers, which comprised 268 newly developed SSRs, 37 previously published SSRs and 53 sequence-related amplified polymorphism markers, were used for genetic map construction. The map for Asian lotus was 365.67 cM with 47 markers distributed in seven linkage groups. The map for American lotus was 524.51 cM, and contained 177 markers distributed in 11 genetic linkage groups. The number of markers per linkage group ranged from three to 34 with an average genetic distance of 3.97 cM between adjacent markers. Moreover, 171 SSR markers contained in linkage groups were anchored to 97 genomic DNA sequence contigs of ‘Chinese Antique’. The 97 contigs were merged into 60 scaffolds. Conclusion Genetic mapping of SSR markers derived from sequenced contigs in Nelumbo enabled the associated contigs to be anchored in the linkage map and facilitated assembly of the genome sequences of

  5. Quality in hospitals environment; La qualita' nell'ambiente ospedaliero. Studio di prevalenza sull'abitudine al fumo di tabacco tra gli operatori di un ospedale cittadino

    Energy Technology Data Exchange (ETDEWEB)

    Callegaro, G.; Saia, M.; Mariotto, A. [Unita' Sanitaria Locale 16, Padua (Italy). Direzione sanitaria; Buttarello, M. [Ospedale Geriatrico, Padua (Italy). Laboratorio di Patologia Clinica

    2000-10-01

    sottoposto era composto da persone che avevamo fumato negli ultimi sei mesi, il 29% era composto da non fumatori, mentre il 30.5% da ex-fumatori. Nei confronti del fumo passivo e delle problematiche fumo-indotte emerge la necessita' di proporre una valida strategia atta a sensibilizzare anche il personale ospedaliero.

  6. How can AN Approach to Steam BE Authentic to both Science and Art?

    Science.gov (United States)

    LaFayette, C. J.; Parke, Ph D., F. I.; Pierce, C.; Nakamura, T.

    2015-12-01

    A collaborative project engaged a team of geophysicists, engineers, entomologists, and artists to visualize tunnels and chambers of a vast, leafcutting ant colony in rural Texas. Part of the plan was to test the nature of significant outcomes in different domains and contexts. Our team used Ground Penetrating Radar to scan part of the nest, then translate the data into 3D geometry to be experienced on an immersive visualization system. This provided the ability to zoom out of and into the model. The tunnel fragment could appear like a tiny crumb floating in air, or one could move inside it to view details and tunnel architecture. Exterior and interior structure could thus be perceived in a seamless way. The system enabled a kinesthetic sense — one both saw and felt surrounded by the scene. This was the first time GPR had been used to map a living ant colony. Due to this project, entomologists have begun to use GPR with encouraging results. The Atta project inspired in us an enjoyment of experimentation and collaboration. Results were exhibited in international art venues, published in scientific journals, and demonstrated at hybrid venues for art and science. Each form of dissemination was suited to the host. Whether the result can be called art, science, or a blend is determined by its reception in a larger community. Like the species name and the pathway worn from tree to nest, the process of mapping the colony took the form of a palindrome: we pulled something out of the ground, passed it back and forth, and hoisted it out into the world. The role of art in collaboration with science can take many forms. Art can enhance science understanding for non-scientists. Artists and scientists can co-invent new tools for inquiry. Artists are adept at creating ways to experience and understand data or phenomena through multi-modal experiences, for example, aural, haptic, or olfactory. Artists are trained to foreground the process of making as part of the "performance

  7. Characterization and development of EST-derived SSR markers in cultivated sweetpotato (Ipomoea batatas

    Directory of Open Access Journals (Sweden)

    Li Yujun

    2011-10-01

    Full Text Available Abstract Background Currently there exists a limited availability of genetic marker resources in sweetpotato (Ipomoea batatas, which is hindering genetic research in this species. It is necessary to develop more molecular markers for potential use in sweetpotato genetic research. With the newly developed next generation sequencing technology, large amount of transcribed sequences of sweetpotato have been generated and are available for identifying SSR markers by data mining. Results In this study, we investigated 181,615 ESTs for the identification and development of SSR markers. In total, 8,294 SSRs were identified from 7,163 SSR-containing unique ESTs. On an average, one SSR was found per 7.1 kb of EST sequence with tri-nucleotide motifs (42.9% being the most abundant followed by di- (41.2%, tetra- (9.2%, penta- (3.7% and hexa-nucleotide (3.1% repeat types. The top five motifs included AG/CT (26.9%, AAG/CTT (13.5%, AT/TA (10.6%, CCG/CGG (5.8% and AAT/ATT (4.5%. After removing possible duplicate of published EST-SSRs of sweetpotato, a total of non-repeat 7,958 SSR motifs were identified. Based on these SSR-containing sequences, 1,060 pairs of high-quality SSR primers were designed and used for validation of the amplification and assessment of the polymorphism between two parents of one mapping population (E Shu 3 Hao and Guang 2k-30 and eight accessions of cultivated sweetpotatoes. The results showed that 816 primer pairs could yield reproducible and strong amplification products, of which 195 (23.9% and 342 (41.9% primer pairs exhibited polymorphism between E Shu 3 Hao and Guang 2k-30 and among the 8 cultivated sweetpotatoes, respectively. Conclusion This study gives an insight into the frequency, type and distribution of sweetpotato EST-SSRs and demonstrates successful development of EST-SSR markers in cultivated sweetpotato. These EST-SSR markers could enrich the current resource of molecular markers for the sweetpotato community and would

  8. The evolution of genome size in ants

    Directory of Open Access Journals (Sweden)

    Spagna Joseph C

    2008-02-01

    Full Text Available Abstract Background Despite the economic and ecological importance of ants, genomic tools for this family (Formicidae remain woefully scarce. Knowledge of genome size, for example, is a useful and necessary prerequisite for the development of many genomic resources, yet it has been reported for only one ant species (Solenopsis invicta, and the two published estimates for this species differ by 146.7 Mb (0.15 pg. Results Here, we report the genome size for 40 species of ants distributed across 10 of the 20 currently recognized subfamilies, thus making Formicidae the 4th most surveyed insect family and elevating the Hymenoptera to the 5th most surveyed insect order. Our analysis spans much of the ant phylogeny, from the less derived Amblyoponinae and Ponerinae to the more derived Myrmicinae, Formicinae and Dolichoderinae. We include a number of interesting and important taxa, including the invasive Argentine ant (Linepithema humile, Neotropical army ants (genera Eciton and Labidus, trapjaw ants (Odontomachus, fungus-growing ants (Apterostigma, Atta and Sericomyrmex, harvester ants (Messor, Pheidole and Pogonomyrmex, carpenter ants (Camponotus, a fire ant (Solenopsis, and a bulldog ant (Myrmecia. Our results show that ants possess small genomes relative to most other insects, yet genome size varies three-fold across this insect family. Moreover, our data suggest that two whole-genome duplications may have occurred in the ancestors of the modern Ectatomma and Apterostigma. Although some previous studies of other taxa have revealed a relationship between genome size and body size, our phylogenetically-controlled analysis of this correlation did not reveal a significant relationship. Conclusion This is the first analysis of genome size in ants (Formicidae and the first across multiple species of social insects. We show that genome size is a variable trait that can evolve gradually over long time spans, as well as rapidly, through processes that may

  9. Citotossicity in immune system's cells exposed in vitro to a microwave electromagnetic field in two different exposure systems operating at mobile telephones frequencies; Citotossicita' in cellule del sistema immunitario esposte in vitro al campo elettromagnetico a microonde in due diversi sistemi espositivi operanti alle frequenze della telefonia mobile

    Energy Technology Data Exchange (ETDEWEB)

    Scarcella, E.; Ardoino, L.; Galloni, P.; Mancini, S.; Marino, C. [ENEA, Divisione Protezione dell' Uomo e degli Ecosistemi, Centro Ricerche Casaccia, Rome (Italy)

    2001-07-01

    funzionamento di cellule macrofagiche stabilizzate e coltivate in vitro (RAW 264.7) responsabili dei meccanismi di difesa specifica e aspecifica del sistema immunitario. Sono stati, inoltre, standardizzati due diversi sistemi espositivi operanti a 900 MHz a differenti livelli di densita' di potenza (da 1 a 100 W/m{sup 2}) per garantire condizioni elettromagnetiche omogenee, idonee condizioni di incubazione delle cellule e la riproducibilita' degli esperimenti. Il lavoro di standardizzazione dei sistemi espositivi e i risultati sperimentali di questa ricerca, che hanno evidenziato differenze significative della crescita e della funzionalita' macrofagica solo al livello di densita' di potenza piu' elevato (100 W/m{sup 2}), ma recuperare dopo 48 ore dall'esposizione, risultano essere preliminari e propedeutici per una programmazione sperimentale futura atta ad approfondire una valutazione bio-tossicologica in vitro.

  10. “Il tempo è lo specchio dell’eternità”. Strategie e strumenti di heritage marketing nelle imprese longeve italiane / “Il tempo è lo specchio dell’eternità” (Time is the mirror of eternity. Heritage marketing strategies and tools In Italian long-lived firms

    Directory of Open Access Journals (Sweden)

    Angelo Riviezzo

    2016-06-01

    Full Text Available Il lavoro mira a indagare l’effettivo grado di utilizzo da parte delle imprese longeve italiane dei molteplici strumenti potenzialmente a disposizione per valorizzare in chiave strategica il proprio vissuto storico. A tal fi ne, si propone una sistematizzazione della letteratura sul tema atta a identificare in maniera puntuale i vari strumenti di heritage marketing e, successivamente, se ne indaga l’effettiva diffusione. In particolare, sono state raccolte e analizzate informazioni accurate sulle attività realizzate da 238 imprese di medie e grandi dimensioni iscritte nel Registro nazionale delle imprese storiche italiane di Unioncamere. L’indagine ha rivelato che le imprese longeve approcciano i singoli strumenti di heritage marketing in modo sperimentale e in mancanza di una visione integrata. Sono una minoranza quelle che mostrano di percepire i vantaggi di una convinta e pluriforme azione di valorizzazione del proprio vissuto storico. Il lavoro costituisce il primo esempio d’indagine su larga scala volta a investigare l’utilizzo dei diversi strumenti di heritage marketing e, rispetto a precedenti studi, si distingue per la numerosità delle imprese analizzate e per la completezza e l’eterogeneità degli strumenti considerati. The main aim of this study is to understand if and how Italian long-lived firms are oriented towards a strategic exploitation of their cultural and historical heritage. To this aim, first we reviewed the extant literature on the topic in order to identify the different tools potentially available to implement a heritage marketing strategy and, then, we investigated their actual level of use. A desk research covered 238 medium and large firms entered in the National Register of Italian Historical Firms edited by Unioncamere. For each firm we collected timely information about the different activities of heritage marketing carried out. Our study reveals that long-lived firms approach the single tools of

  11. EDITORIAL: A support for prospective nanomaterials A support for prospective nanomaterials

    Science.gov (United States)

    Demming, Anna

    2011-01-01

    , often touted as a pioneer of a 'bottom-up' approach to nanotechnology, once said 'I was born not knowing and have had only a little time to change that here and there'. In a similar sense, what we do not yet know and understand about the ability to create and manipulate nanosystems is apparently infinite, but as can also be acceded in the case of Richard Feynman, the 'little' we have had time learn so far holds more than a little promise. References [1] Glass R, Möller M and Spatz J P 2003 Nanotechnology 14 314 [2] Kuzyk A, Laitinen K T and Törmä P 2009 Nanotechnology 20 235305 [3] Williams S M, Rodriguez K R, Teeters-Kennedy S, Shah S, Rogers T M, Stafford A D and Coe J V 2004 Nanotechnology 15 S495 [4] Bini T B, Gao S, Tan T C, Wang S, Lim, A, Hai L B and Ramakrishna S 2004 Nanotechnology 15 1459 [5] Yang F, Murugan R, Wang S and Ramakrishna S 2005 Biomaterials 26 2603-10 [6] Tampieri A, Landi E, Valentini F, Sandri M, D'Alessandro T, Dediu V and Marcacci M 2011 Nanotechnology 22 015104 [7] Gross A F, Ahn C C, Van Atta S L, Liu P and Vajo J J 2009 Nanotechnology 20 204005 [8] Zhang S, Gross A F, Van Atta S L, Lopez M, Liu P, Ahn C C, Vajo J J and Jensen C M 2009 Nanotechnology 20 204027

  12. Investigation of Deep Ocean Circulation and Mixing Using Ar-39 (Invited)

    Science.gov (United States)

    Smethie, W. M.; Schlosser, P.

    2013-12-01

    are about 270, 190, and 330 years respectively. Radiocarbon also provides information on circulation and mixing in the deep ocean and thousands of measurements have been made. However, the distributions of Ar-39 and C-14 are different due to the large difference in their half-lives (269 years and 5730 years respectively). Measurement of both tracers provides information on the relative importance of advection and mixing in the deep ocean and provides more accurate transit times than can be obtained with only one of these tracers. In the Atlantic Ocean, where the deep water is roughly a two-end member mixture of northern component and southern component water, the age of the two components can be estimated from simultaneous measurement of Ar-39 and C-14. The few existing measurements suggest that the northern component water has an age range of 40-200 years and the southern component water a range of 60-600 years. Development of the ATTA method for measuring radioactive noble gases offers great potential to dramatically increase the number of samples that can be measured for Ar-39, which could greatly improve our understanding of mixing and circulation in the deep ocean.

  13. Effect of dietary fiber in lowering serum glucose and body weight in sprague dawley rats

    Directory of Open Access Journals (Sweden)

    Muhammad Imran Chohan

    2011-08-01

    Full Text Available Introduction:The present study evaluated the hypoglycemic perspectives and weight loss significance of dietary fiber. Dietary fiber was supplemented in commercial wheat flour (atta for the preparation of chapaties, a staple diet of South Asia. Male Sprague Dawley rats (n = 100 were randomly divided into 4 diet groups (n = 25 per group. The control group was fed basal diet that included commercial wheat flour chapati, cornstarch, corn oil, salt and vitamin mixture in such a way that 10% of the protein was available from the final diet. To the basal diet of other 3 groups, chapaties supplemented with 2% guar gum (GG 2%, 3% guar gum (GG 3% and 5% chickpea + 1% guar gum (CP5%+GG1% were added, respectively. All diets were fed to the rats for a period of 8 weeks to perceive the impact of respective compositions. Rats fed on CP 5% + GG1%, showed maximum glucose reduction (14.57% followed by GG 3% (11.64% and GG 2% (9.60% as compared to control diet. Likewise, rats fed on 3% GG showed maximum decline (7.90% in body weight. It was concluded that chapaties prepared from selected treatments provide an additional dietary fiber that could be supportive for diabetic and obese individuals.Results:The results indicated that addition of dietary fiber influenced the physical characteristics of chapati non-significantly. Maximum glucose concentration was found to be 112.50 mg/dL in control group followed by 101.70 and 99.41 mg/dL in groups fed on guar gum 2% and guar gum 3%, respectively. Lowest glucose concentration (96.11 mg/dL was observed in rats fed on the combination of chickpea 5 %+ guar gum 1%. Maximum serum protein concentration was found to be 6.39 g/dL in rats fed on combination of chickpea 5 % + guar gum 1% whilst the remaining three groups showed non significant variations with respect to each other. Means for serum Functional Foods in Health and Disease 2011; 8:261-278 protein were 6.33, 6.30 and 6.32 g/dL for control, guar gum 3%, and guar gum 2

  14. A Highly-efficient Energy-saving Wireless Body Area Network MAC Protocol%一种高效节能的无线体域网MAC层协议

    Institute of Scientific and Technical Information of China (English)

    谢语天; 王珺; 闵建民; 司桂静

    2015-01-01

    With the rapid development of wireless sensor network technology,wearable and implantable biosensor technology,wearable and implantable wireless equipment can be used for remote monitoring signs information. To link the nodes and equipment which are atta-ched with person skin,implanted in person and surround people,wireless body area network arises at the historic moment. In WBAN, MAC protocol is responsible of conflict detection and processing,priority control,timeslot assignment,transmission order etc. So the de-sign of MAC protocol plays an important role in the reliability and efficiency of WBAN. In this paper,propose a high efficiency and ener-gy-saving MAC protocol (HE-MAC),which is based on IEEE 802. 15. 6. The protocol adopts dynamic priority control,dynamic time-slot allocation mechanism,dynamic proportion allocation mechanism of different access period length to achieve reliable transmission in the situation of low latency and low power consumption. By using the OMNet++ simulation platform,evaluate the network performance of AD-MAC protocol,IEEE 802. 15. 6 MAC protocol and CA-MAC protocol. The result of simulation shows that the proposed MAC protocol is superior to IEEE 802. 15. 6 MAC and CA-MAC in terms of throughput,power consumption and time delay.%随着无线传感网技术、可穿戴和可植入生物传感器技术的快速发展,可穿戴式和可植入式无线设备可用于远程监控体征信息. 为了连接附着于人身上、植入人体内部的节点和存在于人体周围的设备,无线体域网应运而生. 在无线体域网中,MaC协议负责节点的冲突检测与处理,优先级控制、时隙分配以及节点传输顺序,故MaC协议的设计在无线体域网的可靠性和能效性上发挥着核心作用. 文中提出了一种基于IEEE 802. 15. 6高效节能的MaC协议( HE-MaC). 该协议采用动态化的优先级控制、时隙分配机制、不同接入期长度的动态比例分配等措施实现低时延、低功

  15. A new approach to constrain basal helium flux into aquifers for better estimation of groundwater ages by Helium 4

    Science.gov (United States)

    Matsumoto, Takuya; Sturchio, Neil C.; Chang, Hung K.; Gastmans, Didier; Araguas-Araguas, Luis J.; Jiang, Wei; Lu, Zheng-Tian; Mueller, Peter; Yokochi, Reika; Purtschert, Roland; Zongyu, Chen; Shuiming, Hu; Aggarwal, Pradeep K.

    2016-04-01

    Estimation of groundwater age through the combined use of isotope methods and groundwater flow modelling is the common approach used for developing the required level of knowledge in the case of groundwater pumped from deep aquifers. For more than 50 years radiocarbon and tritium have been the common tools used in isotope hydrology studies to provide first estimates of groundwater age and dynamics. The half-life of carbon-14 (5730 years) and the complex geochemistry of carbon species in most environments have limited the proper characterization of groundwater flow patterns in large sedimentary basins and deep aquifers to ages more recent than about 40 000 years. Over the last years, a number of long-live radionuclides and other isotopes have been tested as more reliable age indicators by specialised laboratories. Among these methods, chlorine-36 (half-life of 300 000 yr) has been used with mixed results, mainly due to problems derived from in-situ production of this radionuclide. Uranium isotopes have also been used in a few instances, but never became a routine tool. Accumulation of helium-4 in deep groundwaters has also been proposed and used in a few instance, but one major obstacle in the 4He dating method is a difficulty in assessing a rate constant of 4He input into aquifers (namely, the entering basal 4He flux). In this context, recent breakthrough developments in analytical methods allow the precise determination of dissolved noble gases in groundwater as well as trace-level noble gas radionuclides present in very old groundwaters. Atom trap trace analysis, or ATTA, has dramatically improved over the last years the processing of very small amount of noble gases, providing now real possibilities for routine measurements of extremely low concentration of exotic radionuclides dissolved in groundwater, such as krypton-81 (half-life 229 000 years). Atom trap trace analysis involves the selective capture of individual atoms of a given isotope using six laser

  16. Molecular identification of green tide algae in the South Yellow Sea and preliminary study on its nutritive value%南黄海绿潮藻的分子鉴定及营养价值初探

    Institute of Scientific and Technical Information of China (English)

    蔡子豪; 杜晶; 孙彬; 何培民; 马家海

    2016-01-01

    对2014年度南黄海绿潮藻进行分子鉴定和营养价值初步研究。 ITS序列分析结果显示,南黄海绿潮藻主要包括Ulva linza-procera-prolifera( LPP)以及Ulva compressa 2个类群。营养价值分析结果显示,南黄海绿潮藻中必需氨基酸与氨基酸总量的比值(EAA/TAA)为30.31%~33.83%,呈味氨基酸含量较高(42.84%~46.89%),脂肪酸组成丰富,其不饱和脂肪酸中α-亚麻酸含量占总脂肪酸的(32.36±6.58)%,蛋白质含量与浙江固着浒苔相近(独立样本t 检验, P >0.05),是一种高蛋白(26.46%~29.01%)、低脂肪(0.76%~0.91%)、富含纤维(4.87%~6.58%)且安全的海藻食品。%Based on molecular identification ,the nutritive value of green tide algae from the South Yellow Sea in 2014 was studied in this research .ITS sequence analysis showed that green tide algae in the South Yellow Sea were include in Ulva linza-procera-prolifera( LPP) and Ulva compressa.Nutritive value analysis indicated that green tide algae in the South Yellow Sea was a new safe and healthy sea food providing higher protein (26.46%-29.01%),lower fat (0.76%-0.91%) and higher dietary fiber (4.87%-6.58%), whose protein content was similar with the atta-ched algae from Zhejiang(independent t-test,P>0.05).The amino acid composition of protein was balance with 30.31%-33.83% for EAA/TAA, and the flavor amino acids contents were high ( 42.84%-46.89%); mean-while, the compositions of fatty acids in green tide algae from the South Yellow Sea were rich ,the contents of alpha linolenic acid was (32.36 ±6.58)%of total fatty acids .The green tide algae was a safe seaweed food with high pro-tein content (26.46%-29.01%), low fat content (0.76%-0.91%) and high fiber content (4.87%-6.58%).

  17. Histopathological changes of Macaca mulatta infected with Plasmodium knowlesi%恒河猴感染诺氏疟原虫的病理组织学变化

    Institute of Scientific and Technical Information of China (English)

    陈林; 李国桥; 户耀增; 罗灼玲

    2001-01-01

    目的探讨诺氏疟原虫(Plasmodium knowlesi)感染恒河猴(Macaca mu1atta)引起有关脏器的病理组织学变 化。 方法病解3例感染疟原虫未经治疗病死的猴;2例感染疟原虫经青蒿琥酯(artesunate)栓剂治疗后又复发 的猴;1例感染疟原虫经磷酸哌喹(piperaquine phosphate)治愈后死于上肢坏死感染的猴。对有关脏器均进 行切片检查。 结果 3例(1号、7号和12号)未经治疗而病死的猴和1例(72号)虽经青蒿琥酯栓剂治疗但很快被排出 体外的猴的心、肝、脾、肺、肾、大小脑、胰腺、甲状旁腺、脑垂体和淋巴结等均有严重病变,含原虫的红细胞 和疟色素聚集于这些脏器的毛细血管内。1例(131号)经用哌喹治愈而死于上肢坏死的猴,除见多个脏器 内有色素沉积或被巨噬细胞吞噬外,可见胰岛细胞、甲状旁腺和垂体细胞萎缩和消失等病变。1例(33号) 用青蒿琥酯栓剂治疗后短期原虫转阴,但又复燃的猴被灌药致死,多个脏器所见与感染后未经治疗者明显 不同,仅见肝脏Kupffer细胞和大脑基质细胞内含原虫和疟色素,多个脏器均呈修复。 结论本文报导了诺氏疟原虫感染恒河猴后各有关脏器的病理组织学变化,特别是观察到胰岛细胞、甲状 旁腺和垂体细胞的萎缩和消失与心肌细胞的溶解是国内外文献所未记载过的。%Objective To study the histopathological changes of relevant intemal organs of Macaca mulatta infected with Plasmodium knowlesi ( P. knowlesi). Methods Histopathological examination of 3 monkeys who died of P. knowlesi infection, 2 P. knowlesi infected monkeys who died of treatment failure with artesunate suppository and 1 P. knowlesi infected monkey that was cured by piperaquine phosphate (PQP) but died of trauma and necrosis of the fore limb. Results The heart, liver, spleen, lung, kidney, brain, pancreas, parathyriod, pituitary and lymph nodes showed severe

  18. The characteristics of epiphytic microbes of three submerged macrophytes in Lake Hua-shen%南京花神湖3种沉水植物表面附着微生物群落特征

    Institute of Scientific and Technical Information of China (English)

    刘凯辉; 张松贺; 吕小央; 郭川; 韩冰; 周为民

    2015-01-01

    沉水植物表面附着微生物系统是水生态的重要组成部分,然而当前对其了解仍不清楚.南京市花神湖是一个城市湖泊,沉水植物生长区域面积占湖面面积的40%左右.尽管花神湖的氮、磷营养盐水平很高,但最近未发生过藻类水华现象.本文以南京市花神湖中自然生长的优势种菹草( Potamogeton crispus)、伊乐藻( Elodea nuttallii)和金鱼藻( Ceratophyl-lum demersum)为研究对象,利用扫描电镜和荧光显微镜观测了叶表面附着微生物群落的分布特征,测定了植物表面附着微生物的密度及附生藻类的种类、密度和优势种群,并比较分析了不同水生植物之间附生藻类的差异性.结果表明,沉水植物表面微生物群落的分布与物种和叶龄有关.3种沉水植物中,菹草表面微生物群落结构最为复杂,微生境最为丰富.底部老叶片上面附着较多的微生物且表现出较高的生物多样性.植物表面附着微生物密度大小顺序为:菹草>金鱼藻>伊乐藻;植物表面附生藻类密度大小顺序为:菹草>金鱼藻>伊乐藻.总体来讲,沉水植物表面微生物总量大概比藻类数量高1~2个数量级.这为深入研究沉水植物及其表面微生物的生态功能奠定了基础.%Submerged plants-epiphytic microbes system is an important component of aquatic ecosystems , but little is known about their status and roles.Lake Huashen is an urban lake, where submerged plants occupied about 40%of the water surface.Although concentrations of nutrients (P and N) were high in Lake Huashen, the algal blooms have never occurred in recent years.In order to explain this phenomenon in Lake Huashen , we determined the density of epiphytic microbes and dominant epiphytic algae atta-ched on the surface of three submersed macrophytes including Potamogeton crispus, Elodea nuttallii and Ceratophyllum demersum, investigated their

  19. Meliponini neotropicais: o gênero Partamona Schwarz, 1939 (Hymenoptera, Apidae, Apinae - bionomia e biogeografia Neotropical Meliponini: the genus Partamona Schwarz, 1939 (Hymenoptera, Apidae, Apinae - bionomy and biogeography

    Directory of Open Access Journals (Sweden)

    João M. F. Camargo

    2003-01-01

    termitaria, such as cavities and crevices in walls, among roots of epiphytes and in bases of palm leaves, in abandoned bird nests, under bridges, and in other protected places, except P. peckolti that occasionally occupies termite nests. In South America, on the eastern side of the Andes, only P. epiphytophila and P. helleri nest among roots of epiphytes and other substrates, non-associated with termitaria. All other species studied (P. batesi, P. gregaria, P. pearsoni, P. ferreirai, P. chapadicola, P. nhambiquara, P. vicina, P. mourei, P. auripennis, P. combinata, P. cupira, P. mulata, P. ailyae, P. seridoensis, P. criptica and P. rustica nest inside active termite nests, whether epigeous or arboreous. The only species that builds obligate subterranean nests, associated or not with termite or ant nests (Atta spp. is P. testacea. Nests of Partamona have one vestibular chamber (autapomorphic for the genus closely adjacent to the entrance, filled with a labyrinth of anastomosing pillars and connectives, made of earth and resins. One principal chamber exists for food and brood, but in some species one or more additional chambers are filled with food storage pots. In nests of P. vicina, there is one atrium or "false nest", between the vestibule and the brood chamber, which contains involucral sheaths, cells and empty pots. All structures of the nest are supported by permanent pillars made of earth and resins (another autapomorphy of the genus. The characters concerning nesting habits were coded and combined with morphological and biogeographic data, in order to hypothesize the evolutive scenario of the genus using cladistic methodology. The phylogenetic hypothesis presented is the following: (((((P. bilineata (P. grandipennis, P. xanthogastra (P. orizabaensis, P. peckolti (P. aequatoriana, P. musarum P. epiphytophila, P. yungarum, P. subtilis, P. vitae (((((P. testacea (P. mourei, P. vicina (P. nigrior (P. auripennis, P. combinata (P. ferreirai (P. pearsoni (P. gregaria (P

  20. MEMORIAS III Encuentro Científico de Estudiantes de Biología

    Directory of Open Access Journals (Sweden)

    Acta Biológica Colombiana

    2003-12-01

    de biomasa por una colonia de atta laevigatasmith 1958 (hymenoptera: formicidae en los Llanos Orientales (Puerto López, Meta, Colombia / Manejo ex situde crías de crocodylus intermedius(crocodylidae, una experiencia como estudiante de práctica académica / Caracterización del llamado de advertencia de colostethus bocagei(amphibia: dendrobatidae en el municipio de Ibagué, Colombia / Caracterización del llamado de advertencia de colostethus bocagei(amphibia: dendrobatidae en el municipio de Ibagué, Colombia / Uso etnomédico de algunas especies vegetales del departamento del Chocó, Colombia / Morfología y herbivoría en las especies del género tococa(melastomataceae con mirmecomacios / Fauna Asociada a la Medicina Tradicional del Departamento Del Chocó, Colombia / Hongos alucinógenos: el desconocimiento cultural de su consumo / Relación insecto-hongo: desarrollo de dípteros en panaeolus foenisecii (basidiomycotina-agariclaes / Estudio preliminar de algunos aspectos biológicos de hoplias malabaricusbloch 1794 (Quicharo en la microcuenca de Cabí, Chocó, Colomba / Composición y estructura de la vegetación terrestre aledaña al Río Gaira (Departamento Del Magdalena, Colombia / Relaciones de herbivoría por insectos sobre Lantana sp. (Verbenacea, Piper sp.(Piperaceae y Miconia sp.(Asteraceae en Moniquirá (Boyacá, Colombia.

  1. MFGA-IDT2 workshop: Astrophysical and geophysical fluid mechanics: the impact of data on turbulence theories

    Directory of Open Access Journals (Sweden)

    D. Schertzer

    1996-01-01

    ... up to the very large scale of the Universe. The presentations and the round table at the end of the workshop pointed out the following: - the necessity of this type of confrontation which makes intervene numerical simulations, laboratory experiments, phenomenology as well as a very large diversity of geophysical and astrophysical data, - presumably a relative need for new geophysical data, whereas there have been recent astrophysical experiments which yield interesting data and exciting questions; - the need to develop a closer intercomparison between various intermittency models (in particular Log-Poisson /Log Levy models. Two main questions were underlined, in particular during the round table: - the behaviour of the extremes of intermittency, in particular the question of divergence or convergence of the highest statistical moments (equivalently, do the probability distributions have algebraic or more rapid falloffs?; - the extension of scaling ranges; in other words do we need to divide geophysics and astrophysics in many small (nearly isotropic subranges or is it sufficient to use anisotropic scaling notions over wider ranges? 4 The contributions in this special issue Recalling that some of the most useful insights into the nature of turbulence in fluids have come from observations of geophysical flows, Van Atta gives a review of the impacts of geophysical turbulence data into theories. His paper starts from Taylor's inference of the nearly isotropy of atmospheric turbulence and the corresponding elegant theoretical developments by von Karman of the theory of isotropic turbulence, up to underline the fact that the observed extremely large intermittency in geophysical turbulence also raised new fundamental questions for turbulence theory. The paper discusses the potential contribution to theoretical development from the available or currently being made geophysical turbulence measurements, as well as from some recent laboratory measurements and direct numerical

  2. 减毒百日咳杆菌注射部位与实验性变态反应性脑脊髓炎大鼠模型诱导效果的关系%Relation between the injected site of pertussis toxin and the induced effect on experimental allergic encephalomyelitis in rats

    Institute of Scientific and Technical Information of China (English)

    马太花; 尉杰忠; 武慧丽; 辛静敏; 梁丽云; 马存根

    2006-01-01

    BACKGROUND: The animals commonly used to induce experimental allergic encephalomyelitis (EAE) in oversea laboratory are rodentia animals such as Lewis rats. But in China we are short of Lewis rats. The un-susceptive animal Wistar rats are inexpensive and plentiful. The adding of pertussis toxin may induce EAE successfully in EAE un-susceptive Wistar rats.OBJECTIVE: To investigate the influence of pertussis toxin injected atdifferent sites in inducing EAE model in un-susceptive Wistar rats.DESIGN: A randomized control animal experiment.SETTING: Institute of Brain Science, Shanxi Datong University.MATERIALS: The study was performed in the Institute of Brain Science of Shanxi Datong University from March to October in 2003. Fifty-eight und adjuvant (CFA) group (n=10).METHODS: Besides routine immunization, each rat in the foot dorsum EAE group and intraperitoneal EAE group was administrated with 005 mL pertussis toxin (containing 5.0×1010 thalli), which were given intraperitoneally and subcutaneously on one hind foot respectively, and the antigen in the CFA group was replaced by CFA.cidence rate and tine of atta ck: In the foot dorsum EAE group, the incidence of EAE was 87.5% (21/24), and the time of attack was at (10.25 ±1.67) days after immunization, which were significantly different from those in the intraperitoneal EAE group [35.7% (9/24), (14.8±l.79) days, P sum EAE group, the change of body mass was (-16.00±7.30) g and the symptomscpre was 3.4±0.7, and those in the intraperitoneal EAE group Therewere no or little infiltration of inflammatory cells in the encephalon and spinal cord of CFA rats. In the EAE rats, there were inflammatory cells infiltrated in the boundary of white matter and gray matter of lumbar intumescence, spinal pia mater, spinal parenehyma, and the boundary of cerebral cortex and medulla, even deep medulla, meninges and around lateral ventricle. There were also mild inflammations in the cerebellum,brainstem and optic chiasma, which were

  3. Δοκίμιο για την κοινωνική εξέλιξη στη διάρκεια των λεγόμενων «σκοτεινών αιώνων»

    Directory of Open Access Journals (Sweden)

    Τηλέμαχος Κ. ΛΟΥΓΓΗΣ

    1985-09-01

    èmes; la soi-disante rébellion des Arméniaques en 793 ; l'apparition de la nouvelle aristocratie dans la Chronique de l'an 811; le rôle des mouvements populaires (Thomas le Slave et, dans une certaine mesure, les Pauliciens; les relations entre l'armée et le clergé à tout moment donné; la destinée des officiers moyens de l'armée après la capitulation idéologique de leurs chefs; les initiatives politiques de la nouvelle aristocratie; l'attitude de Michel II le Bègue en tant que premier empereur qui s'appuie consciemment sur la nou­velle aristocratie; la révolte avortée de Bardanès Tourcos etc.L'étude vise à démontrer que toutes les transformations politiques, institutionnelles etc. qui ont dû avoir lieu pendant les «siècles obscurs» sont des produits concrets et directs ou indirects d'une lutte sociale très réelle et très profonde à la fois qui a mené à de changements de structures, à de changements qualitatifs. Tandis que la noblesse proto­byzantine était composée par la noblesse sénatoriale, la noblesse des villes de province et le clergé, la noblesse mésobyzantine est composée principalement par l'armée et le clergé (vu que m. A. Guillou a déjà re­marqué en ce qui concerne l'exarchat de Ravenne au VIIe siècle. Une attention particulière est accordée aux vicissitudes du rôle des militaires, depuis la «terreur» de Phocas jusqu'à l'avènement de Basile Ier. Quelques empereurs, tel Constantin IV ou Anastase II perdent quelque chose de leur auréole, tandis que d'autres, tel Constant II et Justinien II sont placés sans louanges dans le vrai contexte politique de leur époque. Toute la structure de l'étude, en dernière analyse, tend à soutenir que des affirmations comme «Héraclius s'est trompé d'ennemi (au lieu d'atta­quer les Arabes, il a détruit la Perse!!!, ou «tel empereur est mort très jeune» ou encore «Michel III était bon ou mauvais empereur» n'ont au­cune place dans la science de l'Histoire et doivent