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Sample records for biomphalaria glabrata intermediate

  1. A bacterial artificial chromosome library for Biomphalaria glabrata, intermediate snail host of Schistosoma mansoni

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    Coen M Adema

    2006-10-01

    Full Text Available To provide a novel resource for analysis of the genome of Biomphalaria glabrata, members of the international Biomphalaria glabrata Genome Initiative (biology.unm.edu/biomphalaria-genome.html, working with the Arizona Genomics Institute (AGI and supported by the National Human Genome Research Institute (NHGRI, produced a high quality bacterial artificial chromosome (BAC library. The BB02 strain B. glabrata, a field isolate (Belo Horizonte, Minas Gerais, Brasil that is susceptible to several strains of Schistosoma mansoni, was selfed for two generations to reduce haplotype diversity in the offspring. High molecular weight DNA was isolated from ovotestes of 40 snails, partially digested with HindIII, and ligated into pAGIBAC1 vector. The resulting B. glabrata BAC library (BG_BBa consists of 61824 clones (136.3 kb average insert size and provides 9.05 × coverage of the 931 Mb genome. Probing with single/low copy number genes from B. glabrata and fingerprinting of selected BAC clones indicated that the BAC library sufficiently represents the gene complement. BAC end sequence data (514 reads, 299860 nt indicated that the genome of B. glabrata contains ~ 63% AT, and disclosed several novel genes, transposable elements, and groups of high frequency sequence elements. This BG_BBa BAC library, available from AGI at cost to the research community, gains in relevance because BB02 strain B. glabrata is targeted whole genome sequencing by NHGRI.

  2. Ionotropic Receptors Identified within the Tentacle of the Freshwater Snail Biomphalaria glabrata, an Intermediate Host of Schistosoma mansoni.

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    Di Liang

    Full Text Available Biomphalaria glabrata (B. glabrata is an air-breathing aquatic mollusc found in freshwater habitats across the Western Hemisphere. It is most well-known for its recognized capacity to act as a major intermediate host for Schistosoma mansoni, the human blood fluke parasite. Ionotropic receptors (IRs, a variant family of the ionotropic glutamate receptors (iGluR, have an evolutionary ancient function in detecting odors to initiate chemosensory signaling. In this study, we applied an array of methods towards the goal of identifying IR-like family members in B. glabrata, ultimately revealing two types, the iGluR and IR. Sequence alignment showed that three ligand-binding residues are conserved in most Biomphalaria iGluR sequences, while the IRs did exhibit a variable pattern, lacking some or all known glutamate-interactingresidues, supporting their distinct classification from the iGluRs. We show that B. glabrata contains 7 putative IRs, some of which are expressed within its chemosensory organs. To further investigate a role for the more ancient IR25a type in chemoreception, we tested its spatial distribution pattern within the snail cephalic tentacle by in situ hybridization. The presence of IR25a within presumptive sensory neurons supports a role for this receptor in olfactory processing, contributing to our understanding of the molecular pathways that are involved in Biomphalaria olfactory processing.

  3. Biomphalaria glabrata no Estado do Piauí Biomphalaria glabrata in the State of Piaui

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    W. Lobato Paraense

    1984-09-01

    Full Text Available É registrado o primeiro encontro do molusco planorbideo Biomphalaria glabrata, hospedeiro intermediário do Schistosoma mansoni, no Estado do Piauí, coletado em vários criadouros na cidade de Parnaíba. O exame de 694 exemplares revelou a presença de formas evolutivas de algumas espécies de trematodeos, mas não de Schistosomatidea. Nenhum caso autoctone de xistosomose foi até agora identificado na população humana da cidade. A presença da B. glabrata em Parnaíba amplia em 20 km para leste a área de sua distribuição na Região Litoral Norte da Grande Região Nordeste do Brasil onde era conhecida até em Avaioses no extremo leste da parte maranhense da referida Região. Outros moluscos também coletados nos mesmos criadouros foram Biomphalaria straminea, Drepanotrema lucidum. D. cimex, D. depressissimum, Physidae e Ampullarriidae.The occurrence of Biomphalaria glabrata is recorded for the first time in the state of Piauí, where it was collected from several breeding places in the city of Parnaíba. Examination of 694 specimens showed that a part of them were infected with trematodes other than Schistosomatidae. So far no autochthonous cases of schistosomiasis have been identified in the city. The presence of B. glabrata in Parnaíba extends by 20 Km eastward its range on the Northern Coastal region of the Great Northeastern region of Brazil, where it had been found as far as Araioses, on the eastern extreme of the state of Maranhão. Other snail species collected from the same breeding places were Biomphalaria straminea, Drepanotrema lucidum, D. cimex, D. depressissimum, Physidae and Ampullariidae.

  4. Contribution to the histology of Biomphalaria glabrata Contribuição à histologia da Biomphalaria glabrata

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    Queli Teixeira Lemos

    1999-01-01

    A combination of histological techniques applied to the study of Biomphalaria glabrata yielded some interesting new data about the histology of this snail, a major intermediate host of Schistosoma mansoni in Brazil. Three kinds of pigments were identified: a dark pigment which bleached following oxidation with potassium permanganate; a lipofuchsin-like, diastase-resistant PAS-positive pigment and an iron-containing pigment, probably related to hemosiderin. Calcium was detected in small deposi...

  5. Development of Schistosoma mansoni in Biomphalaria tenagophila, Biomphalaria straminea and Biomphalaria glabrata Desenvolvimento do Schistosoma mansoni em Biomphalaria tenagophila, Biomphalaria straminea e Biomphalaria glabrata

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    Cecilia Pereira de Souza

    1995-06-01

    Full Text Available A comparative study of the development of Schistosoma mansoni during the intra-molluscan phase was made by means of histological sections of Biomphalaria tenagophila, B. straminea and B. glabrata from Brazil. Two hundred snails of each species were individually exposed to 50 miracidia of the S. mansoni, AL line. No larvae were observed in the snails fixed 72 h after exposure. In specimens shedding cercariae, 31 days after exposure tissue reactions encapsulating the larvae were seen in B. tenagophila and B. straminea, in the head-foot, mantle collar and renal ducts. No tissue reactions occurred in the digestive glands of these two species. In B. glabrata the presence of numerous sporocysts and cercariae without tissue reactions was observed in the digestive gland, and other organs. The levels of infection of the snails and the average numbers of cercariae shed per day were 32.6% and 79±90 respectively for B. tenagophila, 11.3% and 112±100 for B. straminea and 75.3% and 432±436 for B. glabrata. The lower levels of infection and average numbers of cercariae shed by B. tenagophila and B. straminea are thus related to their more potent internal defense systems.Foi feito estudo comparativo do desenvolvimento do Schistosoma mansoni na fase intra-molusco, através de cortes histológicos, em Biomphalaria tenagophila, B. straminea e B. glabrata. Duzentos moluscos de cada espécie foram expostos individualmente a 50 miracídios de S. mansoni da linhagem AL. Nenhuma larva foi observada nos exemplares fixados 72 horas após a exposição. Nos exemplares eliminando cercárías, 31 dias após a exposição, foram observadas reações teciduais de encapsulamento de larvas em B. tenagophila e B. straminea, na região cefalopodal, colar do manto e dutos renais. Nas glândulas digestivas das duas espécies não foram observadas reações. Em B. glabrata foi registrada a presença de numerosos esporocistos e cercárias sem reação tecidual na gl

  6. Schistosomiasis Control Using Piplartine against Biomphalaria glabrata at Different Developmental Stages

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    Rapado, Ludmila Nakamura; Pinheiro, Alessandro de Sá; Lopes, Priscila Orechio de Moraes Victor; Fokoue, Harold Hilarion; Scotti, Marcus Tullius; Marques, Joaquim Vogt; Ohlweiler, Fernanda Pires; Borrely, Sueli Ivone; Pereira, Carlos Alberto de Bragança; Kato, Massuo Jorge; Nakano, Eliana; Yamaguchi, Lydia Fumiko

    2013-01-01

    Background Schistosomiasis is one of the most significant diseases in tropical countries and affects almost 200 million people worldwide. The application of molluscicides to eliminate the parasite's intermediate host, Biomphalaria glabrata, from infected water supplies is one strategy currently being used to control the disease. Previous studies have shown a potent molluscicidal activity of crude extracts from Piper species, with extracts from Piper tuberculatum being among the most active. M...

  7. Contribution to the histology of Biomphalaria glabrata Contribuição à histologia da Biomphalaria glabrata

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    Queli Teixeira Lemos

    1999-08-01

    Full Text Available A combination of histological techniques applied to the study of Biomphalaria glabrata yielded some interesting new data about the histology of this snail, a major intermediate host of Schistosoma mansoni in Brazil. Three kinds of pigments were identified: a dark pigment which bleached following oxidation with potassium permanganate; a lipofuchsin-like, diastase-resistant PAS-positive pigment and an iron-containing pigment, probably related to hemosiderin. Calcium was detected in small deposits within the connective tissue and forming a dense core inside the chitinous radular teeth. The presence of fibrils, staining with sirius-red and birefringence under polarized light strongly suggest primitive collagen tissue. The radular apparatus appeared as a storing site for glycogen, while abundant Alcian-blue positive material (proteoglycans was extremely concentrated in the radular sac.Uma combinação de várias técnicas histológicas permitiu alguns achados de interesse para a histologia da Biomphalaria glabrata, principal hospedeiro intermediário do Schistosoma mansoni no Brasil. Três tipos de pigmentos foram identificados: um pigmento escuro, que se descora após oxidação pelo permanganato de potássio; outro que é semelhante à lipofuscina, que se cora pelo PAS e é diastase- resistente, e um pigmento que contém ferro, provalvelmente, relacionado com a hemossiderina. O cálcio foi identificado em pequenos depósitos no interior do tecido conjuntivo e formando pequenos núcleos no interior dos dentes quitinosos da rádula. A presença de fibrilas coradas pelo sírius-vermelho, exibindo birrefrigência sob luz polarizada, sugere fortemente a presença de um tecido colágeno primitivo. O aparelho radular foi visto como um local de armazenamento do glicogênio, enquanto a presença de abundante material amorfo positivo para o azul de alciano (proteoglicano apareceu em grande concentração no saco radular.

  8. Atividade moluscicida de alguns produtos naturais sobre Biomphalaria glabrata Molluscicide activity of some natural products on Biomphalaria glabrata

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    Nelymar Martineli Mendes; Cecília Pereira de Souza; Neusa Araújo; José Pedro Pereira; Naftale Katz

    1986-01-01

    Foi avaliada, em laboratório, a ação moluscicida de extratos aquosos (macerado e fervido), hexânico e etanólico de Aristolochia brasiliensis, Caesalpinia peltophoroides, Caesalpinia pulcherrima, Delonix regia, Spathodea campanulata e Tibouchina scrobiculata. As soluções dos extratos obtidos foram testadas sobre caramujos adultos e desovas de Biomphalaria glabrata, criados em laboratório, nas concentrações de 1, 10, 20, 200 e 1000ppm. Dos extratos testado o mais ativo foi o etanólico das flore...

  9. Weight loss and survival of Biomphalaria Glabrata deprived of water

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    Marc Vianey-Liaud

    1986-06-01

    Full Text Available Immature and mature Biomphalaria glabrata are kept out of water at relative humidities varying from 0 to 100%. When snails are submitted to a saturated atmosphere, they show a slow weight loss and survival may be long. If relative humidity (RH decreases, weight loss becomes important and survival is short. A reduced RH (0 to 65% produces similar effects. During desiccation, fasting has no noticeable effect; survival depends essentially on weight loss.Biomphalaria glabrata maduros ou imaturos são mantidos fora da água, variando a umidade de 0 a 100%. Quando caramujos são submetidos a uma atmosfera saturada, sofrem uma lenta perda de peso e a sobrevivência pode ser longa. Se a umidade relativa decresce, a perda de peso será importante e a sobrevida será abreviada. Uma umidade relativa de 0 a 65% pode produzir efeitos similares. Durante a dessecação, a privação de alimento não tem efeito notável, a sobrevivência dependendo essencialmente da perda de peso.

  10. OVICIDAL EFFECT OF PIPERACEAE SPECIES ON Biomphalaria glabrata, Schistosoma mansoni HOST

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    Ludmila Nakamura Rapado

    2013-12-01

    Full Text Available SUMMARY Schistosomiasis is a neglected disease with public health importance in tropical and subtropical regions. An alternative to the disease control is the use of molluscicides to eliminate or reduce the intermediate host snail population causing a reduction of transmission in endemic regions. In this study nine extracts from eight Piperaceae species were evaluated against Biomphalaria glabrata embryos at blastula stage. The extracts were evaluated in concentrations ranging from 100 to 10 mg/L. Piper crassinervium and Piper tuberculatum extracts were the most active (100% of mortality at 20 mg/L and 30 mg/L respectively.

  11. OVICIDAL EFFECT OF PIPERACEAE SPECIES ON Biomphalaria glabrata, Schistosoma mansoni HOST

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    Rapado, Ludmila Nakamura; Lopes, Priscila Orechio de Moraes; Yamaguchi, Lydia Fumiko; Nakano, Eliana

    2013-01-01

    SUMMARY Schistosomiasis is a neglected disease with public health importance in tropical and subtropical regions. An alternative to the disease control is the use of molluscicides to eliminate or reduce the intermediate host snail population causing a reduction of transmission in endemic regions. In this study nine extracts from eight Piperaceae species were evaluated against Biomphalaria glabrata embryos at blastula stage. The extracts were evaluated in concentrations ranging from 100 to 10 mg/L. Piper crassinervium and Piper tuberculatum extracts were the most active (100% of mortality at 20 mg/L and 30 mg/L respectively). PMID:24213196

  12. Atividade moluscicida de alguns produtos naturais sobre Biomphalaria glabrata Molluscicide activity of some natural products on Biomphalaria glabrata

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    Nelymar Martineli Mendes

    1986-03-01

    Full Text Available Foi avaliada, em laboratório, a ação moluscicida de extratos aquosos (macerado e fervido, hexânico e etanólico de Aristolochia brasiliensis, Caesalpinia peltophoroides, Caesalpinia pulcherrima, Delonix regia, Spathodea campanulata e Tibouchina scrobiculata. As soluções dos extratos obtidos foram testadas sobre caramujos adultos e desovas de Biomphalaria glabrata, criados em laboratório, nas concentrações de 1, 10, 20, 200 e 1000ppm. Dos extratos testado o mais ativo foi o etanólico das flores da D. regia (flamboyant que apresentou atividade moluscicida sobre caramujos adultos na concentração de 20ppm.The molluscicide activity of aqueous (macerated and boiled, hexamic and ethylic extracts of Aristolochia brasiliensis, Caesalpinia peltophoroides, Caesalpinia pulcherrima, Delonix regia, Spathodea campanulata and Tibouchina scrobiculata was evaluated in the laboratory. The solutions obtained from those extracts were tested on adults and egg masses of Biomphalaria glabrata reared in the laboratory at 1, 10, 20, 100 and 1000ppm concentrations. The most active of the extracts studied was D. regia flowers' (flamboyant ethylic extracts which presented molluscicidal activity on adult snails at 20ppm.

  13. On the origin of the Biomphalaria glabrata hemocytes

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    Samaly dos Santos Souza

    2006-10-01

    Full Text Available A histologic, morphometric and ultrastructural study performed on Biomphalaria glabrata submitted to infection with Schistosoma mansoni miracidia failed to provide significant evidences that the so-called amebocyte-producing organ (APO is really the central organ for hemocyte production. In infected snails no general reactive changes appeared in the APO, the mitoses were seen only occasionally, and the possibility of cellular hyperplasia was ruled out by morphometric measurements. Under the electron microscope the APO cells presented an essentially epithelial structure, without features indicative of transition toward hemocytes. On the other hand, the present findings pointed to a multicentric origin for the mollusck hemocytes, as earlier studies had indicated. Dense foci of hemocyte collections appeared sometimes around disintegrating sporocysts and cercariae in several organs and tissues of the infected snails, including a curious accumulation of such cells inside the ventricular cavity of the heart. In the heart and other sites, features suggestive of transformation of vascular space endothelial lining cells into hemocytes were apparent. To some extent, the postulated multicentric origin for B. glabrata hemocytes recapitulates earlier embryologic findings in vertebrates, when mesenchymal vascular spaces generate the circulating and phagocytic blood cells.

  14. Seleção genética de Biomphalaria glabrata e Biomphalaria tenagophila visando a alteração da suscetibilidade e resistência ao Schistosoma mansoni Genetic selection of Biomphalaria glabrata and Biomphalaria tenagophila seeking the alteration of the susceptibility and resistance to the Schistosoma mansoni

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    Nádia Regina Borim Zuim

    2005-10-01

    Full Text Available Gerações de Biomphalaria glabrata e Biomphalaria tenagophila selecionadas geneticamente para resistência e suscetibilidade ao Schistosoma mansoni das linhagens BH e SJ foram utilizadas no estudo da adaptação do trematódeo ao hospedeiro intermediário. As gerações dos planorbídeos foram obtidas por autofecundação dos moluscos que se apresentaram suscetíveis ou resistentes após a exposição aos miracídios de Schistosoma mansoni. Para Biomphalaria glabrata foram obtidas as gerações: Parental, F1S (Suscetível, F1R (Resistente, F2S e F2R. Para a Biomphalaria tenagophila foram estudadas as gerações: Parental, F1S, F1R e F50S. A comparação das taxas de infecção apresentadas pelas diferentes gerações mostrou que, em ambas as espécies, o aumento da suscetibilidade foi mais facilmente obtido do que o aumento da resistência. A dificuldade em aumentar a resistência do molusco ao S. mansoni tem fortes implicações epidemiológicas.Generations of Biomphalaria glabrata and Biomphalaria tenagophila selected genetically for resistance and susceptibility to Schistosoma mansoni of strains BH and SJ were used in a study of the trematode adaptation to the intermediate host. Descendants of the planorbids were obtained by self-fertilization of the mollusks that became susceptible or resistant after exposure to the miracidia of Schistosoma mansoni. For Biomphalaria glabrata they were obtained from the following generations: Parental, F1S (Susceptible, F1R (Resistant, F2S and F2R. For Biomphalaria tenagophila the studied generations were: Parental, F1S, F1R and F50S. The comparison of the infection rates presented by the different generations showed that the increase in susceptibility was more easily obtained in both species. The difficulty in increasing the resistance of the mollusks to Schistosoma mansoni has important epidemiologic implications.

  15. The molluscicidal activity of niclosamide (Bayluscide WP70®) on Melanoides tuberculata (Thiaridae), a snail associated with habitats of Biomphalaria glabrata (Planorbidae)

    OpenAIRE

    2002-01-01

    The aim of this study was to determine the toxicity of niclosamide (Bayluscide ®) on Melanoides tuberculata and Biomphalaria glabrata under laboratory conditions. The latter species is the intermediate host of Schistosoma mansoni (Sambon 1917). M. tuberculata was successfully used as competitor of B. glabrata in biological control programs in French West Indies. Both molluscicide and biological control using M. tuberculata have proved to be successful in reducing the population density of B. ...

  16. Repovoamento de criadouros de Biomphalaria glabrata após tratamento com niclosamida Repopulation of breeding habitats of Biomphalaria glabrata after treatment with niclosamide

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    Cecília Pereira de Souza; Nelymar Martineli Mendes

    1991-01-01

    Experimentos foram feitos no laboratório e no campo nos anos de 1980 a 1984, objetivando detectar as causas do repovoamento de criadouros de Biomphalaria glabrata após tratamento com niclosamida. Os bioensaios no laboratório mostraram que a suscetibilidade à niclosamida emulsionável de B. glabrata coletada mensalmente em um sistema de valas de irrigação, variou durante o ano. As concentrações letais CL90 foram 0,15 mgl-1 a 0,60 mgl-1, apresentando diferenças significantes estatisticamente (p ...

  17. Influence of gamma radiation on the levels of polyphenols and lethality of ethanol extracts of Anacardium occidentale Linn., against Biomphalaria glabrata; Influencia da radiacao gama na acao moluscicida de extratos de cajueiro em Biomphalaria glabrata

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    Santos, G.H.F.; Silva, E.B., E-mail: santosghf@hotmail.com [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear. Grupo de Radioprotecao e Radioecologia; Melo, A.M.M.A.; Lima, C.S.A [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Biofisica; Amorim, E.L.C.; Peixoto Sobrinho, T.J.S. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Farmacia

    2013-08-15

    Plant materials rich in phenolic compounds, such as Anacardium occidentale Linn., Have been used as alternatives to synthetic pesticides in Biomphalaria glabrata control programs, intermediate host of Schistosoma mansoni. Studies show that ionizing radiation can influence the content of phenolic compounds and thus their biological actions. The aim of this study was to evaluate the influence of gamma radiation of {sup 60}Co in polyphenol composition of hydroalcoholic extracts of bark and leaves of A. occidentale and evaluate the toxicity of these extracts to embryos and adults of B. glabrata. To achieve this goal this, the extracts were irradiated at 10 kGy, the controls being maintained from 0 kGy and positive (CaCO{sub 3}) and negative (H{sub 2}O). We quantified the total phenols by the Folin-Ciocalteau and tannins by precipitation of casein. Extracts were used at a concentration of 100 mg/L. The results showed that the radiation caused the changes to the leaves, the percentage of polyphenols and tannins, and the percentage of lethality in embryos and adults Biomphalaria glabrata, these percentages being: 13 ± 5 (0 kGy) and 27 ± 2.5 (10 kGy), and 36.67 ± 5.77 (0 kGy), and 56.67 ± 5.77 (10 kGy), respectively. Gamma radiation caused significant changes in the levels of polyphenols in the extracts of leaves of Anacardium ocidentale Linn., translated by the increased toxicity of this extract against embryos and adults of Biomphalaria glabrata. This indicates that gamma radiation can be used as an agent potentiating the toxicity of plant extracts on the alternate use of these materials as molluscicides. (author)

  18. Schistosomiasis control using piplartine against Biomphalaria glabrata at different developmental stages.

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    Ludmila Nakamura Rapado

    Full Text Available BACKGROUND: Schistosomiasis is one of the most significant diseases in tropical countries and affects almost 200 million people worldwide. The application of molluscicides to eliminate the parasite's intermediate host, Biomphalaria glabrata, from infected water supplies is one strategy currently being used to control the disease. Previous studies have shown a potent molluscicidal activity of crude extracts from Piper species, with extracts from Piper tuberculatum being among the most active. METHODS AND FINDINGS: The molluscicidal activity of P. tuberculatum was monitored on methanolic extracts from different organs (roots, leaves, fruit and stems. The compounds responsible for the molluscicidal activity were identified using (1H NMR and ESIMS data and multivariate analyses, including principal component analysis and partial least squares. These results indicated that the high molluscicidal activity displayed by root extracts (LC50 20.28 µg/ml was due to the presence of piplartine, a well-known biologically-active amide. Piplartine was isolated from P. tuberculatum root extracts, and the molluscicidal activity of this compound on adults and embryos of B. glabrata was determined. The compound displayed potent activity against all developmental stages of B. glabrata. Next, the environmental toxicity of piplartine was evaluated using the microcrustacean Daphnia similis (LC50 7.32 µg/ml and the fish Danio rerio (1.69 µg/ml. The toxicity to these organisms was less compared with the toxicity of niclosamide, a commercial molluscicide. CONCLUSIONS: The development of a new, natural molluscicide is highly desirable, particularly because the commercially available molluscicide niclosamide is highly toxic to some organisms in the environment (LC50 0.25 µg/ml to D. similis and 0.12 µg/ml to D. rerio. Thus, piplartine is a potential candidate for a natural molluscicide that has been extracted from a tropical plant species and showed less toxic to

  19. Schistosomiasis Control Using Piplartine against Biomphalaria glabrata at Different Developmental Stages

    Science.gov (United States)

    Rapado, Ludmila Nakamura; Pinheiro, Alessandro de Sá; Lopes, Priscila Orechio de Moraes Victor; Fokoue, Harold Hilarion; Scotti, Marcus Tullius; Marques, Joaquim Vogt; Ohlweiler, Fernanda Pires; Borrely, Sueli Ivone; Pereira, Carlos Alberto de Bragança; Kato, Massuo Jorge; Nakano, Eliana; Yamaguchi, Lydia Fumiko

    2013-01-01

    Background Schistosomiasis is one of the most significant diseases in tropical countries and affects almost 200 million people worldwide. The application of molluscicides to eliminate the parasite's intermediate host, Biomphalaria glabrata, from infected water supplies is one strategy currently being used to control the disease. Previous studies have shown a potent molluscicidal activity of crude extracts from Piper species, with extracts from Piper tuberculatum being among the most active. Methods and Findings The molluscicidal activity of P. tuberculatum was monitored on methanolic extracts from different organs (roots, leaves, fruit and stems). The compounds responsible for the molluscicidal activity were identified using 1H NMR and ESIMS data and multivariate analyses, including principal component analysis and partial least squares. These results indicated that the high molluscicidal activity displayed by root extracts (LC50 20.28 µg/ml) was due to the presence of piplartine, a well-known biologically-active amide. Piplartine was isolated from P. tuberculatum root extracts, and the molluscicidal activity of this compound on adults and embryos of B. glabrata was determined. The compound displayed potent activity against all developmental stages of B. glabrata. Next, the environmental toxicity of piplartine was evaluated using the microcrustacean Daphnia similis (LC50 7.32 µg/ml) and the fish Danio rerio (1.69 µg/ml). The toxicity to these organisms was less compared with the toxicity of niclosamide, a commercial molluscicide. Conclusions The development of a new, natural molluscicide is highly desirable, particularly because the commercially available molluscicide niclosamide is highly toxic to some organisms in the environment (LC50 0.25 µg/ml to D. similis and 0.12 µg/ml to D. rerio). Thus, piplartine is a potential candidate for a natural molluscicide that has been extracted from a tropical plant species and showed less toxic to environment. PMID

  20. Aspectos histológicos das gônadas hermafroditas de Biomphalaria glabrata e Bradybaena similaris (Mollusca, Gastropoda, Pulmonata

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    Rinaldo Florêncio da Silva

    2009-01-01

    Full Text Available Biomphalaria glabrata (Say, 1818 é um gastrópode pulmonado de água doce que desperta grande interesse médico e veterinário. Bradybaena similaris (Férussac, 1821 é um gastrópode pulmonado terrestre considerado uma praga agrícola de plantações de hortaliças. Ambas as espécies são hospedeiras intermediárias de helmintos. Esses moluscos possuem uma gônada hermafrodita produtora de óvulos e espermatozóides de forma simultânea. Neste estudo foram avaliados aspectos histomorfológicos das gônadas hermafroditas de B. glabrata e B. similaris. A gônada de B. similaris encontra-se subdividida em lobos com glândulas em seu interior, o que não foi observado em B. glabrata. Além disso, em B. similaris as células germinativas estão acumuladas em determinados pontos e com a presença de um ovócito em cada folículo da gônada; não obstante, em B. glabrata as células germinativas encontraram-se justapostas e com mais de um ovócito em cada folículo.Biomphalaria glabrata (Say, 1818 is a freshwater pulmonate gastropod that represents great medical importance. Bradybaena similaris (Férussac, 1821 is a terrestrial pulmonate gastropod and an important plague to the different plant cultures with economic interest. Both species are intermediate hosts of helminths. These molluscs have hermaphrodites gonads producing eggs and sperm. Here, we examined histoformological aspects of hermaphrodites gonads of both B. glabrata and B. similaris. The gonad of B. similaris is subdivided into lobes and presence of glands in its interior, which was not observed in B. glabrata. Moreover, in B. similaris the germ cells are accumulated in some areas, and has one oocyte in each follicle in the gonad; however, in B. glabrata the germ cells are juxtaposed and more than one oocyte in each follicle.

  1. Repovoamento de criadouros de Biomphalaria glabrata após tratamento com niclosamida Repopulation of breeding habitats of Biomphalaria glabrata after treatment with niclosamide

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    Cecília Pereira de Souza

    1991-08-01

    Full Text Available Experimentos foram feitos no laboratório e no campo nos anos de 1980 a 1984, objetivando detectar as causas do repovoamento de criadouros de Biomphalaria glabrata após tratamento com niclosamida. Os bioensaios no laboratório mostraram que a suscetibilidade à niclosamida emulsionável de B. glabrata coletada mensalmente em um sistema de valas de irrigação, variou durante o ano. As concentrações letais CL90 foram 0,15 mgl-1 a 0,60 mgl-1, apresentando diferenças significantes estatisticamente (p Experiments were undertaken both in the laboratory and in the field between 1980-1984 to evaluate the causes of repopulation of breeding places of Biomphalaria glabrata following treatment with Niclosamide. Laboratory bioassays showed that the susceptibility to emulsifiable Niclosamide of B. glabrata collected monthly from an irrigation ditch system varied during the year. Lethal concentrations (LC90 ranged between 0.15 mg/l-1 and 0.60 mg/l-1. Statistically significant differences (alpha=0.01 were evident between the months of May/82 and January/83 and December/82 and January/83, and were related to snail nutrition. In the field two types of foci of B. glabrata were treated with 10 ppm of Niclosamide. The first one consisted of a reservoir of 12000 1 of water in which 14.5% of snails were infected with Schistosoma mansoni. One application of molluscicide followed by cleaning of the reservoir eliminated all the snails. The second one consisted of an irrigation system in which 5.6% of the snails were infected with S. mansoni. One application of molluscicide without cleaning the ditches reduced the density of snails by 98%. The causes of the survival of 2.0% of the snails in the ditches are discussed in relation to the substratum of the breeding places and the treatment technique.

  2. Atividade moluscicida do extrato butílico de Phytolaca dodecandra (Endod) sobre Biomphalaria glabrata Molluscicide activity of a buthanol extract of Phytolacca dodecandra (Endod) on Biomphalaria glabrata

    OpenAIRE

    Cecília Pereira de Souza; Nelimar Martinelli Mendes; Neusa Araújo; Naftale Katz

    1987-01-01

    O extrato butílico da Phytolacca dodecandra (tipo 44) obtido de frutos procedentes da Etiópia, foi testado como moluscicida em nosso laboratório e no campo. As concentrações letais, CL90, com 24 horas de exposição, para Biomphalaria glabrata adulta, recém-eclodidas e desovadas foram de 4,5, 23,0 e 102,0 ppm, respectivamente. Para peixes, Lebistes reticulatus, a CL90 foi de 2,0 ppm. Esses resultados foram semelhantes aos obtidos por Lemma em 1984, na Etiópia. Em dois criadouros com água parada...

  3. Gamma 60Co DL50/30 of Biomphalaria glabrata (Say, 1818) DL50/30 raios gama de 60Co em Biomphalaria glabrata (Say, 1818)

    OpenAIRE

    Elaine Barros da Costa CARVALHO; Melo, Ana Maria Mendonça de Albuquerque; Mauricy Alves da MOTTA

    1999-01-01

    The variation of resistance to 60Co gamma-rays of Biomphalaria glabrata was studied. A population of 480 mollusks was observed during 30 days - distributed in 8 groups of snails isolated and 8 groups of snails in colonies - after exposure (30 snails per group per dose) to increasing doses of gamma radiation. Doses of 10, 20, 40, 60, 80, 160, 320 and 640 Gy from a Gamma-cell 60Co irradiator, were applied to the test groups and two groups control (non-irradiated) of snails - isolated and colony...

  4. Effects of Plagiorchis elegans (Digenea: Plagiorchiidae) infection on the reproduction of Biomphalaria glabrata (Pulmonata: Planorbidae).

    Science.gov (United States)

    Zakikhani, M; Rau, M E

    1998-10-01

    Infection with the digenean parasite Plagiorchis elegans dramatically reduced the reproductive output of Biomphalaria glabrata exposed to the parasite as juveniles or adults. The total number of eggs produced by infected snails was reduced to approximately 7 and 13% of control values, respectively. Parasitic castration was attributed to the presence of mother sporocysts that readily established in the tissues of this incompatible host. Infection did not result in the production of cercariae but significantly shortened the life span of juvenile and adult B. glabrata by approximately 23 and 10%, respectively. Plagiorchis elegans also castrated its compatible host, Stagnicola elodes. PMID:9794632

  5. Atividade moluscicida do extrato butílico de Phytolaca dodecandra (Endod sobre Biomphalaria glabrata Molluscicide activity of a buthanol extract of Phytolacca dodecandra (Endod on Biomphalaria glabrata

    Directory of Open Access Journals (Sweden)

    Cecília Pereira de Souza

    1987-09-01

    Full Text Available O extrato butílico da Phytolacca dodecandra (tipo 44 obtido de frutos procedentes da Etiópia, foi testado como moluscicida em nosso laboratório e no campo. As concentrações letais, CL90, com 24 horas de exposição, para Biomphalaria glabrata adulta, recém-eclodidas e desovadas foram de 4,5, 23,0 e 102,0 ppm, respectivamente. Para peixes, Lebistes reticulatus, a CL90 foi de 2,0 ppm. Esses resultados foram semelhantes aos obtidos por Lemma em 1984, na Etiópia. Em dois criadouros com água parada, tratados com 10ppm de estrato butílico e 3ppm de niclosamida, ocorreu 84,0 e 100,0% de mortalidade B. glabrata, respectivamente. Os dois produtos foram tóxicos para peixes (L. reticulatus no campo. É discutida a possibilidade do uso de moluscidas de origem vegetal, como alternativa para o combate a focos de esquistossomose no Brasil.A buthanol extract of Phytolacca dodecandra (type 44 obtained from Ethiopia berries, was tested as molluscicide in our laboratory and in the field. The lethal dose (LD90 for adult snails, newly hatched and egg-masses of Biomphalaria glabrata, in 24 hours exposure, were of 4.5, 23.0 and 102.0 ppm respectively. The LD90 for the fish Lebistes reticulatus was of 2.0 ppm. These results are similar to those of Lemma (1984 in Ethiopia. In two water ponds treated with 10 ppm of the buthanol extract or 3 ppm of niclosamide the mortality rates of B. glabrata were of 84.6 and 100.0%, respectively. Both treatments were toxic for L. reticulatus in the field trials. The possibility of using molluscicides derived from plants is discussed as an alternative for treatment of schistosomiasis foci in Brazil.

  6. The nuclear receptors of Biomphalaria glabrata and Lottia gigantea: implications for developing new model organisms.

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    Satwant Kaur

    Full Text Available Nuclear receptors (NRs are transcription regulators involved in an array of diverse physiological functions including key roles in endocrine and metabolic function. The aim of this study was to identify nuclear receptors in the fully sequenced genome of the gastropod snail, Biomphalaria glabrata, intermediate host for Schistosoma mansoni and compare these to known vertebrate NRs, with a view to assessing the snail's potential as a invertebrate model organism for endocrine function, both as a prospective new test organism and to elucidate the fundamental genetic and mechanistic causes of disease. For comparative purposes, the genome of a second gastropod, the owl limpet, Lottia gigantea was also investigated for nuclear receptors. Thirty-nine and thirty-three putative NRs were identified from the B. glabrata and L. gigantea genomes respectively, based on the presence of a conserved DNA-binding domain and/or ligand-binding domain. Nuclear receptor transcript expression was confirmed and sequences were subjected to a comparative phylogenetic analysis, which demonstrated that these molluscs have representatives of all the major NR subfamilies (1-6. Many of the identified NRs are conserved between vertebrates and invertebrates, however differences exist, most notably, the absence of receptors of Group 3C, which includes some of the vertebrate endocrine hormone targets. The mollusc genomes also contain NR homologues that are present in insects and nematodes but not in vertebrates, such as Group 1J (HR48/DAF12/HR96. The identification of many shared receptors between humans and molluscs indicates the potential for molluscs as model organisms; however the absence of several steroid hormone receptors indicates snail endocrine systems are fundamentally different.

  7. Influence of experimental illumination and seasonal variation on crossbreending mating in the snail Biomphalaria Glabrata

    OpenAIRE

    F. Pimentel-Souza; V. T. Schall; N. D. C. Barbosa; Schettino, M.; R. Lautner Júnior.

    1988-01-01

    The crossbreeding activities of the Schistosoma mansoni vector snail Biomphalaria glabrata were counted in a laboratory aquarium throughout the year under two regimes of 12h light: 12h dark from 7 A., M. to 10 P. M. Mating increased significantly in Authmn and Winter and just missed a significant inverse correlation with temperature and a direct one with locomotion. Other similar experiments were carried out to compare mating under various ilumination conditions in complete daily cycle measur...

  8. Circulating Biomphalaria glabrata hemocyte subpopulations possess shared schistosome glycans and receptors capable of binding larval glycoconjugates

    OpenAIRE

    YOSHINO, TIMOTHY P.; Wu, Xiao-Jun; Gonzalez, Laura A.; Cornelis H Hokke

    2012-01-01

    Host lectin-like recognition molecules may play an important role in innate resistance in Biomphalaria glabrata snails to larval schistosome infection, thus implicating parasite-expressed glycans as putative ligands for these lectin receptors. While host lectins may utilize specific glycan structures for parasite recognition, it also has been hypothesized that the parasite may use this system to evade immune detection by mimicking naturally-expressed host glycans, resulting in reduced immunor...

  9. Profile of organic acid concentrations in the digestive gland and hemolymph of Biomphalaria glabrata under estivation

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    José Clecildo Barreto Bezerra

    1999-11-01

    Full Text Available Using high performance liquid chromatography (HPLC analysis it was possible to determine simultaneously the concentration of organic acids (pyruvate, lactate, succinate, fumarate, malate, acetate, propionate, acetoacetate, and ß-hydroxybutyrate in the digestive gland and the extracellular concentration of these same acids in the hemolymph of estivating Biomphalaria glabrata, the intermediate host of Schistosoma mansoni. After a 7 day period of estivation, there was a significant increase in the tissue levels of lactate, succinate, malate and acetate compared to non-estivating snails. After 14 days of estivation, the levels of lactate and acetate were also significantly elevated. The hemolymph concentrations of pyruvate and acetate increased significantly after 7 days and acetate concentrations continued to be significantly increased up to 14 days of estivation. The other organic acids studied, such as ketone body acetoacetate and ß-hydroxybutyrate or the volatile acid propionate, did not accumulate. Their tissue concentrations, however, increased on the 7th day of estivation and reached normal levels within two weeks of estivation for some of them. One should take into consideration how the reduction in metabolism can be handled under aerobic conditions, and what role anaerobic pathways may play in both energy formation and redox balance processes.

  10. Ecology of bacterial communities in the schistosomiasis vector snailBiomphalaria glabrata.

    Science.gov (United States)

    Ducklow, H W; Clausen, K; Mitchell, R

    1981-09-01

    The internal colony-forming bacterial flora of the schistosome intermediate host snailBiomphalaria glabrata (Say) has been characterized in ca. 500 individual snails from Puerto Rico, Guadeloupe, and St. Lucia, and from laboratory aquaria. Freshly captured wild snails harbor 2-40×10(6) CFU·g(-1), and healthy aquarium snails harbor 4-16×10(7) CFU·g(-1), whereas moribund individuals have 4-10 times as many bacteria as healthy individuals from the same habitats.Pseudomonas spp. are the most common predominant bacteria in normal snails, whereasAcinetobacter, Aeromonas, andMoraxella spp. predominate in moribund snails. External bacterial populations in water appear to have little effect on the composition and size of the flora in any snail. In addition to normal (healthy) and moribund snails, a third group of snails has been distinguished on the basis of internal bacterial density and predominating genera. These "high-density" snails may have undergone stresses and may harbor opportunistic pathogens. The microfloras of wild and laboratory-reared snails can be altered and stimulated to increase in density by crowding the snails or treating them with antibiotics. PMID:24227500

  11. Evaluation of radiosensitivity hemocytes of Biomphalaria glabrata exposed to gamma radiation; Avaliacao da radiossensibilidade de hemocitos de Biomphalaria glabrata expostos a radiacao gama

    Energy Technology Data Exchange (ETDEWEB)

    Silva, L.R.S.; Amaral, A.J., E-mail: luannaribeiro_lua@hotmail.com [Universidade Federal de Pernambuco (UFPE), Recife-PE (Brazil). Dept. de Energia Nuclear; Silva, E.B. [Universidade Federal de Pernambuco (UFPE), Vitoria de Santo Antao, PE (Brazil). Centro Academico de Vitoria; Amancio, F.F.; Melo, A.M.M.A. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Biofisica e Radiobiologia

    2013-06-15

    The mollusc Biomphalaria glabrata have characteristics that allow them to be identified as an animal model ideal for monitoring areas exposed to chemical agents and physical. This study evaluated the effect of ionizing radiation from Cobalt-60 in haemocytes present in the hemolymph of Biomphalaria glabrata, with the goal of using these cells as indicators of the presence of radiation in aquatic environments. The mollusks were divided into five groups: one control and four subjected doses of 25, 35, 45 and 55 Gy of gamma radiation. After 48 hours of irradiation, the clam hemolymph was collected and slides were prepared and stained with Giemsa for analyses under a light microscope. Statistical analysis was performed using ANOVA and Tukey's test, p <0.05. The results showed that the total number of cells after irradiation reduced compared to control except at a dose of 55 Gy. During data analysis, morphological changes were observed in haemocytes of mollusks subjected to doses of 35, 45 and 55 Gy. These modifications consisted of nucleus bilobulated and nucleo plasmatic bridges. Another change was exclusively observed in the cellular exposure of 55 Gy, where hemocytes showed misshapen nuclei and cytoplasm vacuolisation, suggestive of apoptosis. It is concluded that hemocytes are sensitive to radiation and can be used as indicators of the presence of high doses of ionizing radiation in aquatic environments. (author)

  12. Antigenic community between Schistosoma mansoni and Biomphalaria glabrata: on the search of candidate antigens for vaccines

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    N Chacón

    2002-10-01

    Full Text Available We have previously confirmed the presence of common antigens between Schistosoma mansoni and its vector, Biomphalaria glabrata. Cross-reactive antigens may be important as possible candidates for vaccine and diagnosis of schistosomiasis. Sera from outbred mice immunized with a soluble Biomphalaria glabrata antigen (SBgA of non-infected B. glabrata snails recognized molecules of SBgA itself and S. mansoni AWA by Western blot. Recognition of several molecules of the SBgA were inhibited by pre-incubation with AWA (16, 30, 36, 60 and 155 kDa. The only specific molecule of AWA, inhibited by SBgA, was a 120 kDa protein. In order to determine which epitopes of SBgA were glycoproteins, the antigen was treated with sodium metaperiodate and compared with non-treated antigen. Molecules of 140, 60 and 24 kDa in the SBgA appear to be glycoproteins. Possible protective effects of the SBgA were evaluated immunizing outbred mice in two different experiments using Freund's Adjuvant. In the first one (12 mice/group, we obtained a significant level of protection (46% in the total worm load, with a high variability in worm recovery. In the second experiment (22 mice/group, no significant protection was observed, neither in worm load nor in egg production per female. Our results suggest that SBgA constitutes a rich source of candidate antigens for diagnosis and prophylactic studies.

  13. Differential spatial repositioning of activated genes in Biomphalaria glabrata snails infected with Schistosoma mansoni.

    Science.gov (United States)

    Arican-Goktas, Halime D; Ittiprasert, Wannaporn; Bridger, Joanna M; Knight, Matty

    2014-09-01

    Schistosomiasis is an infectious disease infecting mammals as the definitive host and fresh water snails as the intermediate host. Understanding the molecular and biochemical relationship between the causative schistosome parasite and its hosts will be key to understanding and ultimately treating and/or eradicating the disease. There is increasing evidence that pathogens that have co-evolved with their hosts can manipulate their hosts' behaviour at various levels to augment an infection. Bacteria, for example, can induce beneficial chromatin remodelling of the host genome. We have previously shown in vitro that Biomphalaria glabrata embryonic cells co-cultured with schistosome miracidia display genes changing their nuclear location and becoming up-regulated. This also happens in vivo in live intact snails, where early exposure to miracidia also elicits non-random repositioning of genes. We reveal differences in the nuclear repositioning between the response of parasite susceptible snails as compared to resistant snails and with normal or live, attenuated parasites. Interestingly, the stress response gene heat shock protein (Hsp) 70 is only repositioned and then up-regulated in susceptible snails with the normal parasite. This movement and change in gene expression seems to be controlled by the parasite. Other differences in the behaviour of genes support the view that some genes are responding to tissue damage, for example the ferritin genes move and are up-regulated whether the snails are either susceptible or resistant and upon exposure to either normal or attenuated parasite. This is the first time host genome reorganisation has been seen in a parasitic host and only the second time for any pathogen. We believe that the parasite elicits a spatio-epigenetic reorganisation of the host genome to induce favourable gene expression for itself and this might represent a fundamental mechanism present in the human host infected with schistosome cercariae as well as in

  14. Effects of high dose rate gamma radiation on survival and reproduction of Biomphalaria glabrata

    International Nuclear Information System (INIS)

    Ionizing radiations are known as mutagenic agents, causing lethality and infertility. This characteristic has motivated its application on animal biological control. In this context, the freshwater snail Biomphalaria glabrata can be considered an excellent experimental model to study effects of ionizing radiations on lethality and reproduction. This work was designed to evaluate effects of 60Co gamma radiation at high dose rate (10.04 kGy/h) on B. glabrata. For this purpose, adult snails were selected and exposed to doses ranging from 20 to 100 Gy, with 10 Gy intervals; one group was kept as control. There was not effect of dose rate in the lethality of gamma radiation; the value of 64,3 Gy of LD50 obtained in our study was similar to that obtained by other authors with low dose rates. Nevertheless, our data suggest that there was a dose rate effect in the reproduction. On all dose levels, radiation improved the production of embryos for all exposed individuals. However, viability indexes were below 6% and, even 65 days after irradiation, fertility was not recovered. These results are not in agreement with other studies using low dose rates. Lethality was obtained in all groups irradiated, and the highest doses presented percentiles of dead animals above 50%. The results demonstrated that doses of 20 and 30 Gy were ideal for population control of B. glabrata. Further studies are needed; nevertheless, this research evidenced great potential of high dose rate gamma radiation on B. glabrata reproductive control. (author)

  15. Effects of high dose rate gamma radiation on survival and reproduction of Biomphalaria glabrata

    Energy Technology Data Exchange (ETDEWEB)

    Cantinha, Rebeca S.; Nakano, Eliana [Instituto Butantan, Sao Paulo, SP (Brazil). Lab. de Parasitologia], e-mail: rebecanuclear@gmail.com, e-mail: eliananakano@butantan.gov.br; Borrely, Sueli I. [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil). Centro de Tecnologia das Radiacoes], e-mail: sborrely@ipen.br; Amaral, Ademir; Melo, Ana M.M.A. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear. Grupo de Estudos em Radioprotecao e Radioecologia (GERAR)], e-mail: amaral@ufpe.br; Silva, Luanna R.S. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Biofisica e Radiobiologia. Lab. de Radiobiologia], e-mail: amdemelo@hotmail.com, e-mail: luannaribeiro_lua@hotmail.com

    2009-07-01

    Ionizing radiations are known as mutagenic agents, causing lethality and infertility. This characteristic has motivated its application on animal biological control. In this context, the freshwater snail Biomphalaria glabrata can be considered an excellent experimental model to study effects of ionizing radiations on lethality and reproduction. This work was designed to evaluate effects of {sup 60}Co gamma radiation at high dose rate (10.04 kGy/h) on B. glabrata. For this purpose, adult snails were selected and exposed to doses ranging from 20 to 100 Gy, with 10 Gy intervals; one group was kept as control. There was not effect of dose rate in the lethality of gamma radiation; the value of 64,3 Gy of LD{sub 50} obtained in our study was similar to that obtained by other authors with low dose rates. Nevertheless, our data suggest that there was a dose rate effect in the reproduction. On all dose levels, radiation improved the production of embryos for all exposed individuals. However, viability indexes were below 6% and, even 65 days after irradiation, fertility was not recovered. These results are not in agreement with other studies using low dose rates. Lethality was obtained in all groups irradiated, and the highest doses presented percentiles of dead animals above 50%. The results demonstrated that doses of 20 and 30 Gy were ideal for population control of B. glabrata. Further studies are needed; nevertheless, this research evidenced great potential of high dose rate gamma radiation on B. glabrata reproductive control. (author)

  16. New insights into the amphibious life of Biomphalaria glabrata and susceptibility of its egg masses to fungal infection

    Science.gov (United States)

    Egg masses of an aquatic snail, Biomphalaria glabrata, matured, and juveniles subsequently eclosed and were mobile in a stable water film of transitory habitats simulated by two different simple test devices described here. The viability of eggs maintained in an unstable film due to low ambient mois...

  17. The molluscicidal activity of niclosamide (Bayluscide WP70® on Melanoides tuberculata (Thiaridae, a snail associated with habitats of Biomphalaria glabrata (Planorbidae

    Directory of Open Access Journals (Sweden)

    Alexandre Giovanelli

    2002-07-01

    Full Text Available The aim of this study was to determine the toxicity of niclosamide (Bayluscide ® on Melanoides tuberculata and Biomphalaria glabrata under laboratory conditions. The latter species is the intermediate host of Schistosoma mansoni (Sambon 1917. M. tuberculata was successfully used as competitor of B. glabrata in biological control programs in French West Indies. Both molluscicide and biological control using M. tuberculata have proved to be successful in reducing the population density of B. glabrata. The associated use of molluscicide in this area would be an effective measure if M. tuberculata were less susceptibility to the molluscicide than B. glabrata. Three hundreds individuals each of B. glabrata and of M. tuberculata, collected in Sumidouro, State of Rio de Janeiro, were used in the experiment. The molluscs were exposed to 14 different concentrations of niclosamide as recommended by the World Health Organization. Probit analysis was used to determine the LC 50 and LC 90. The LC 50 and LC 90 values for B. glabrata were 0.077 mg/l and 0.175 mg/l, respectively and the LC 50 and LC 90 values for M. tuberculata were 0.082 mg/l and 0.221 mg/l respectively. As the lethal concentrations of niclosamide were approximately the same to both species, this could be a disadvantage when controlling B. glabrata with niclosamide in an area of M. tuberculata occurrence. It migth therefore be preferable to utilize the latex extracted from the Euphorbia splendens, which presented a much higher efficiency for B. glabrata than to M. tuberculata.

  18. Nonhemocyte sources of selected lysosomal enzymes in Biomphalaria glabrata, B. tenagophila and B. straminea (Mollusca: Pulmonata

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    Gary E. Rodrick

    1981-09-01

    Full Text Available The specific activities of acid phosphatase, alkaline phosphatase, β-glucuronidase, lysozymes, glutamate-oxalacetate transaminase and glutamate-pyruvate transaminate were determined in the head-foot and digestive gland of Brazilian Biomphalaria glabrata (Touros, B. tenagophila (Caçapava and B. straminea (Monsenhor Gil. All six enzymes were detected inthe 3000g supernatant. Both cytoplasmic enzymes, glutamate-oxalacetate and glutamate-pyruvate transaminase exhibited the highest specific activities. In the case of the four hydrolytic enzymes assayed, β-glucuronidase exhibited the highest specific activity while lysozyme showed the lowest activity. All six enzymes are thought to be produced by cells within the head-foot and digestive gland of B. glabrata, B. tenagophila and B. straminea.Foram determinadas, na massa cefalopedal e na glândula digestiva de Biomphalaria glabrata de Touros (Rio Grande do Norte B. tenagophila de Cacapava (Sao Paulo e B. straminea de Monsenhor Gil (Piauí, as atividades específicas das seguintes enzimas: fosfatase acida, fosfatase alcalina, beta-glucuronidase, lisozima, transaminase glutâmico-oxalacetica e transaminase glutâmico-piruvica. As seis enzimas referidas foram detectadas no sobrenadante a 3000g. Ambas as enzimas citoplasmaticas - transaminases glutamico-oxalacetica e glutamico-piruvica - mostraram as atividades específicas mais altas. No caso das quatro enzimas hidrolíticas, a beta-glucuronidase revelou a mais alta atividade específica, enquanto a lisozima revelou a mais baixa. E admitido que todas as seis enzimas sao produzidas por celulas presentes na massa cefalopedal e na glândula digestiva das tres especies de moluscos examinadas.

  19. Apparent competition through facilitation between Melanoides tuberculata and Biomphalaria glabrata and the control of schistosomiasis

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    Giovanelli Alexandre

    2003-01-01

    Full Text Available Interactions between two species that result in reduced growth rates for both and extinction of one of the species are generally considered cases of asymmetric interspecific competition. Exploitative or interference competition is the usual mechanism invoked. Here we describe another mechanism producing the same result, named apparent competition through facilitation (ACF, observed between Melanoides tuberculata and Biomphalaria glabrata populations. The superior competitor actually gives some benefit to the other species, whose population becomes unstable with progressively increasing oscillations, leading to extinction. A model of ACF using difference equations suggests initial dynamics distinct from traditional interspecific competition. The dynamics of two freshwater snails in the field and in laboratory experiments suggest ACF, and these relations should be considered in studies of schistosomiasis control. ACF could occur in natural populations, but might have gone undetected because the final result is similar to traditional interspecific competition.

  20. Estudo sobre a cópula interespecífica entre moluscos planorbídeos Biomphalaria glabrata e B. tenagophila Inter-specific mating between planorbid snails Biomphalaria glabrata and B. tenagophila

    Directory of Open Access Journals (Sweden)

    Luiz A. Magalhães

    1973-09-01

    Full Text Available Foi estudada a freqüência da cópula interespecífica entre espécimes de Biomphalaria glabrata e B. tenagophila. Os resultados da experiência levaram a conclusão de que há preferência pela cópula intraespecífica, ocorrendo, contudo, cópulas interespecíficas.An experiment on the inter-specific mating of B. glabrata and B. tenagophila snails was related. The results led to conclude that the snails prefer intra-specific mates, even though inter-specific ones occur.

  1. A Comparative Study of the Organic Acid Content of the Hemolymph of Schistosoma mansoni-Resistant and Susceptible Strains of Biomphalaria glabrata

    Directory of Open Access Journals (Sweden)

    José Clecildo Barreto Bezerra

    1997-05-01

    Full Text Available The freshwater snail Biomphalaria glabrata is an intermediate host of the trematode Schistosoma mansoni. However, some strains of B. glabrata are resistant to successful infection by S. mansoni larvae. The present work examines the profile of organic acids present in S. mansoni-resistant and -susceptible strains of B. glabrata, in order to determine whether the type of organic acid present is related to susceptibility. The organic acids were extracted from the hemolymph of two susceptible B. glabrata strains (PR, Puerto Rico and Ba, Jacobina-Bahia from Brazil, and from the resistant strains 13-16-R1 and 10R2, using solid phase extraction procedures followed by high performance liquid chromatography. The organic acids obtained were analyzed and identified by comparison with known standards. Pyruvate, lactate, succinate, malate, fumarate, acetate, propionate, ß-hydroxybutyrate and acetoacetate were detected in all hemolymph samples. Under standard conditions, the concentration of each of these substances varied among the strains tested and appeared to be specific for each strain. An interesting variation was the low concentration of pyruvate in the hemolymph of PR-snails. Only the concentration of fumarate was consistently different (p£ 0.05 between resistant and susceptible strains

  2. Extra-cellular matrix changes in Schistosoma mansoni-infected Biomphalaria glabrata

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    Borges Claudia Maria da Cunha

    2003-01-01

    Full Text Available Reactivity of snails against parasites exhibits a primitive focal reaction, with encapsulation, phagocytosis and destruction of parasite larvae by macrophage-like cells - the hemocytes. This reaction mimics granulomatous inflammation seen in higher animals. However, different from the latter, little is known about the participation of extra-cellular matrix in such snail defense reactions. Normal and Schistosoma mansoni-infected Biomphalaria glabrata of different strains were submitted to cytological, histological, ultrastructural and biochemical methods in order to investigate the behavior of extra-cellular tissues at the site of anti-parasite reactions. In spite of the presence of two cell-types in peripheral hemolymph, only one cell-type was present at the sites of tissue reactions. Although pre-existent collagen and elastic fibers and microfibrils sometimes appeared slightly compressed around focal reactions, no evidences of duplication, synthesis or deposition of connective-tissue extra-cellular components were observed within or around the zones of reactive cell accumulations. Thus, tissue reactions against S. mansoni in the snail B. glabrata appeared exclusively dependent on one specific population of hemocytes.

  3. Sequencing of simple sequence repeat anchored polymerase chain reaction amplification products of Biomphalaria glabrata

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    Caldeira Roberta L

    2002-01-01

    Full Text Available Simple sequence repeat anchored polymerase chain reaction amplification (SSR-PCR is a genetic typing technique based on primers anchored at the 5' or 3' ends of microsatellites, at high primer annealing temperatures. This technique has already been used in studies of genetic variability of several organisms, using different primer designs. In order to conduct a detailed study of the SSR-PCR genomic targets, we cloned and sequenced 20 unique amplification products of two commonly used primers, CAA(CT6 and (CA8RY, using Biomphalaria glabrata genomic DNA as template. The sequences obtained were novel B. glabrata genomic sequences. It was observed that 15 clones contained microsatellites between priming sites. Out of 40 clones, seven contained complex sequence repetitions. One of the repeats that appeared in six of the amplified fragments generated a single band in Southern analysis, indicating that the sequence was not widespread in the genome. Most of the annealing sites for the CAA(CT6 primer contained only the six repeats found within the primer sequence. In conclusion, SSR-PCR is a useful genotyping technique. However, the premise of the SSR-PCR technique, verified with the CAA(CT6 primer, could not be supported since the amplification products did not result necessarily from microsatellite loci amplification.

  4. The role of behavior in the survival of Biomphalaria glabrata in biossays with the plant molluscicide Phytolacca dodecandra O papel do comportamento na sobrevivência de Biomphalaria glabrata submetida a bioensaios com o moluscicida vegetal Phytolacca dodecandra

    OpenAIRE

    P. Jurberg; J. V. Barbosa; Rotenberg, L.

    1988-01-01

    This work examines the role of behavior in the survival of Biomphalaria glabrata exposed to 25, 50 75 and 100 mgl-1 of Phytolacca dodecandra. Time-lapse cinematography was used to quantify accurately the following parameters: (a) frequency of exits from the solution, (b) time spent out of the solution and (c) time elapsed until the first exit from the solution. These behavior patterns were statistically compared between surviving snails and those which later died. The proportion of surviving ...

  5. Avaliação da bioatividade dos extratos de cúrcuma (Curcuma longa L., Zingiberaceae em Artemia salina e Biomphalaria glabrata Bioactivity evaluation of the turmeric (Curcuma longa L., Zingiberaceae extracts in Artemia salina and Biomphalaria glabrata

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    Carlos R. M. da Silva Filho

    2009-12-01

    Full Text Available A cúrcuma é o rizoma limpo, em boas condições, seco e moído da Curcuma longa L., uma planta herbácea da família Zingiberaceae. Visando novas alternativas para o controle da esquistossomose, os extratos de Curcuma longa L. foram testados para a avaliação da atividade moluscicida contra caramujos adultos da espécie Biomphalaria glabrata, e toxicidade (ensaio de letalidade com Artemia salina. A oleoresina e o óleo essencial de cúrcuma foram ativos contra Artemia salina (CL50 = 80,43 e CL50 = 319,82 μg/mL, respectivamente e também ativos contra os indivíduos adultos de Biomphalaria glabrata (CL50 = 58,3 e CL50 = 46,73 μg/mL, respectivamente. A partir dos resultados obtidos pôde ser concluído que ambos os extratos podem constituir uma alternativa no controle da população desses caramujos e na redução da esquistossomose.The turmeric is the clean rhizome at good conditions, dried and powdered of Curcuma longa L., an herbaceous plant of Zingiberaceae family. Aiming new alternatives for Schistosomiasis control, the Curcuma longa L. extracts were tested for molluscicidal activity evaluation against adult snails of Biomphalaria glabrata specie, and the toxicity (Brine Shrimp Lethality-BSL-bioassay. The oleoresin and the essential oil of turmeric were active against Artemia salina (CL50 = 80.43 and CL50 = 319.82 μg.mL-1, respectively and also active against the adult snails of Biomphalaria glabrata (CL50 = 58.3 and CL50 = 46.73 μg.mL-1, respectively. From the obtained results it was concluded that both extracts can constitute an alternative to population control of these snails and in the reduction of Schistosomiasis.

  6. Gamma 60Co DL50/30 of Biomphalaria glabrata (Say, 1818 DL50/30 raios gama de 60Co em Biomphalaria glabrata (Say, 1818

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    Elaine Barros da Costa CARVALHO

    1999-11-01

    Full Text Available The variation of resistance to 60Co gamma-rays of Biomphalaria glabrata was studied. A population of 480 mollusks was observed during 30 days - distributed in 8 groups of snails isolated and 8 groups of snails in colonies - after exposure (30 snails per group per dose to increasing doses of gamma radiation. Doses of 10, 20, 40, 60, 80, 160, 320 and 640 Gy from a Gamma-cell 60Co irradiator, were applied to the test groups and two groups control (non-irradiated of snails - isolated and colony - were kept apart. After have been exposed, the snails were drew back to the aquaria where they were maintained before. The survival was estimated on a daily score of the alive animals in each group-dose, starting after the irradiation exposure day. As a result, the survival self-fertilization forms (DL50/30 = 218.2 Gy was found greater than in cross-fecundation forms. These data point to a low radio-resistance on the cross-fertilization forms - the sexual reproductive form - which is most found in nature. The lower radio-resistance of the cross-fertilization forms suggests the presence of some sex-linked hormonal factor related to this phenomenon.A variação da resistência entre indivíduos em autofecundação e fecundação cruzada de Biomphalaria glabrata foram estudadas. Uma população de 480 moluscos foi observada durante 29 dias, distribuída em 8 grupos de caramujos isolados e 8 grupos em colônias após a exposição (30 caramujos por grupo-dose a doses crescentes de radiação gama. Foram usadas doses de 10, 20, 40, 60, 80, 160, 320 e 640 Gy de um irradiador Gamma-Cell 60Co. Dois grupos não irradiados - isolado e colônia - foram separados como controle e após a irradiação todos os caramujos voltaram para aquários onde viviam antes. A sobrevida foi estimada pela contagem diária dos animais vivos em cada grupo-dose, a partir do dia da irradiação. O resultado mostrou maior sobrevivência nos grupos isolados (DL50/30 = 218.2 Gy que nos grupos

  7. Carbohydrate metabolism alterations in Biomphalaria glabrata infected with Schistosoma mansoni and exposed to Euphorbia splendens var. hislopii latex

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    Clélia Christina Mello-Silva

    2010-07-01

    Full Text Available This paper evaluates the alterations in the glycogen content of tissues (digestive gland and cephalopedal mass and glucose in the haemolymph of Biomphalaria glabrata BH strain infected with Schistosoma mansoni BH strain and exposed to the latex of Euphorbia splendens var. hislopii. A reduction in the glycogen deposits was observed in infected snails exposed and not exposed to latex. However, the exposure to latex caused a greater depletion of the glycogen levels in both sites analysed, especially from the third week onward. The utilisation of latex as a molluscicide to control the population of infected B. glabrata selectively is proposed.

  8. Nitric oxide production by Biomphalaria glabrata haemocytes: effects of Schistosoma mansoni ESPs and regulation through the extracellular signal-regulated kinase pathway

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    Kirk Ruth S

    2009-04-01

    Full Text Available Abstract Background Schistosoma mansoni uses Biomphalaria glabrata as an intermediate host during its complex life cycle. In the snail, the parasite initially transforms from a miracidium into a mother sporocyst and during this process excretory-secretory products (ESPs are released. Nitric oxide (NO and its reactive intermediates play an important role in host defence responses against pathogens. This study therefore aimed to determine the effects of S. mansoni ESPs on NO production in defence cells (haemocytes from schistosome-susceptible and schistosome-resistant B. glabrata strains. As S. mansoni ESPs have previously been shown to inhibit extracellular signal-regulated kinase (ERK phosphorylation (activation in haemocytes from susceptible, but not resistant, B. glabrata the regulation of NO output by ERK in these cells was also investigated. Results Haemocytes from resistant snails challenged with S. mansoni ESPs (20 μg/ml over 5 h displayed an increase in NO production that was 3.3 times greater than that observed for unchallenged haemocytes; lower concentrations of ESPs (0.1–10 μg/ml did not significantly increase NO output. In contrast, haemocytes from susceptible snails showed no significant change in NO output following challenge with ESPs at any concentration used (0.1–20 μg/ml. Western blotting revealed that U0126 (1 μM or 10 μM blocked the phosphorylation (activation status of ERK in haemocytes from both snail strains. Inhibition of ERK signalling by U0126 attenuated considerably intracellular NO production in haemocytes from both susceptible and resistant B. glabrata strains, identifying ERK as a key regulator of NO output in these cells. Conclusion S. mansoni ESPs differentially influence intracellular NO levels in susceptible and resistant B. glabrata haemocytes, possibly through modulation of the ERK signalling pathway. Such effects might facilitate survival of S. mansoni in its intermediate host.

  9. Usnic Acid Potassium Salt: An Alternative for the Control of Biomphalaria glabrata (Say, 1818)

    Science.gov (United States)

    Lima, Vera L. M.; Pereira, Eugênia C.; Falcão, Emerson P. S.; Melo, Ana M. M. A.; da Silva, Nicácio Henrique

    2014-01-01

    In Brazil, the snail Biomphalaria glabrata is the most important vector of schistosomiasis due to its wide geographical distribution, high infection rate and efficient disease transmission. Among the methods of schistosomiasis control, the World Health Organization recommends the use of synthetic molluscicides, such as niclosamide. However, different substances of natural origin have been tested as alternatives for the control or eradication of mollusks. The literature describes the antitumor, antimicrobial and antiviral properties of usnic acid as well as other important activities of common interest between medicine and the environment. However, usnic acid has a low degree of water solubility, which can be a limiting factor for its use, especially in aquatic environments, since the organic solvents commonly used to solubilize this substance can have toxic effects on aquatic biota. Thus, the aim of the present study was to test the potassium salt of usnic acid (potassium usnate) with regard to molluscicidal activity and toxicity to brine shrimp (Artemia salina). To obtain potassium usnate, usnic acid was extracted with diethyl ether isolated and purified from the lichen Cladonia substellata. Biological assays were performed with embryos and adult snails of B. glabrata exposed for 24 h to the usnate solution solubilized in dechlorinated water at 2.5; 5 and 10 µg/ml for embryos, 0.5; 0.9; 1;5 and 10 µg/ml for mollusks and 0.5; 1; 5; 10 µg/ml for A. salina. The lowest lethal concentration for the embryos and adult snails was 10 and 1 µg/ml, respectively. No toxicity to A. salina was found. The results show that modified usnic acid has increased solubility (100%) without losing its biological activity and may be a viable alternative for the control of B. glabrata. PMID:25375098

  10. Suscetibilidade de biomphalaria glabrata, B. straminea e B. tenagophila a diferentes cepas de schistosoma mansoni

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    Luiz Candido de Souza Dias

    1987-08-01

    Full Text Available Em condições experimentais foi estudada a suscetibilidade de Biomphalaria glabrata, B. straminea e B. tenagophila a quatro linhagens humanas (MAP, PTH, UPH, e OuH e duas de roedores silvestres (PTR e VPR do Schistosoma mansoni. Grupos de 50 moluscos foram expostos individualmente a 10 miracídios e observados durante 70 dias. Avaliou-se a suscetibilidade dos moluscos ao parasito por meio da % de animais com esporocistos, % de moluscos que eliminavam cercárias e mortalidade conjunta dos animais expostos e infectados. Exemplares de B. glabrata mineira infectaram-se com cepa simpátrica (MAP e com 5 alopátricas do Estado de São Paulo (PTH, VPH, OuH, PTR e VPR. B. glabrata paulista mostrou altas taxas de infecção com as cepas MAP, VPR e OuH do trematódeo. Quatro % dos exemplares B. straminea de São Paulo eliminavam cercárias de cepas simpátricas; com cepa mineira apenas 4% apresentaram esporocistos na vigência de 20 miracídios por molusco; as menores taxas de mortalidade foram registradas com essa espécie de molusco, não sendo maior do que 20%. B. tenagophila paulista foi suscetível apenas às linhagens simpáticas sendo 6% a maior taxa de moluscos que eliminaram cercárias. Os resultados indicam que os movimentos populacionais humanos dentro do território paulista e para fora dele são importantes na disseminação da esquistossomose mansônica.

  11. Usnic acid potassium salt: an alternative for the control of Biomphalaria glabrata (Say, 1818.

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    Mônica C B Martins

    Full Text Available In Brazil, the snail Biomphalaria glabrata is the most important vector of schistosomiasis due to its wide geographical distribution, high infection rate and efficient disease transmission. Among the methods of schistosomiasis control, the World Health Organization recommends the use of synthetic molluscicides, such as niclosamide. However, different substances of natural origin have been tested as alternatives for the control or eradication of mollusks. The literature describes the antitumor, antimicrobial and antiviral properties of usnic acid as well as other important activities of common interest between medicine and the environment. However, usnic acid has a low degree of water solubility, which can be a limiting factor for its use, especially in aquatic environments, since the organic solvents commonly used to solubilize this substance can have toxic effects on aquatic biota. Thus, the aim of the present study was to test the potassium salt of usnic acid (potassium usnate with regard to molluscicidal activity and toxicity to brine shrimp (Artemia salina. To obtain potassium usnate, usnic acid was extracted with diethyl ether isolated and purified from the lichen Cladonia substellata. Biological assays were performed with embryos and adult snails of B. glabrata exposed for 24 h to the usnate solution solubilized in dechlorinated water at 2.5; 5 and 10 µg/ml for embryos, 0.5; 0.9; 1;5 and 10 µg/ml for mollusks and 0.5; 1; 5; 10 µg/ml for A. salina. The lowest lethal concentration for the embryos and adult snails was 10 and 1 µg/ml, respectively. No toxicity to A. salina was found. The results show that modified usnic acid has increased solubility (100% without losing its biological activity and may be a viable alternative for the control of B. glabrata.

  12. Usnic acid potassium salt: an alternative for the control of Biomphalaria glabrata (Say, 1818).

    Science.gov (United States)

    Martins, Mônica C B; Silva, Monique C; Silva, Luanna R S; Lima, Vera L M; Pereira, Eugênia C; Falcão, Emerson P S; Melo, Ana M M A; da Silva, Nicácio Henrique

    2014-01-01

    In Brazil, the snail Biomphalaria glabrata is the most important vector of schistosomiasis due to its wide geographical distribution, high infection rate and efficient disease transmission. Among the methods of schistosomiasis control, the World Health Organization recommends the use of synthetic molluscicides, such as niclosamide. However, different substances of natural origin have been tested as alternatives for the control or eradication of mollusks. The literature describes the antitumor, antimicrobial and antiviral properties of usnic acid as well as other important activities of common interest between medicine and the environment. However, usnic acid has a low degree of water solubility, which can be a limiting factor for its use, especially in aquatic environments, since the organic solvents commonly used to solubilize this substance can have toxic effects on aquatic biota. Thus, the aim of the present study was to test the potassium salt of usnic acid (potassium usnate) with regard to molluscicidal activity and toxicity to brine shrimp (Artemia salina). To obtain potassium usnate, usnic acid was extracted with diethyl ether isolated and purified from the lichen Cladonia substellata. Biological assays were performed with embryos and adult snails of B. glabrata exposed for 24 h to the usnate solution solubilized in dechlorinated water at 2.5; 5 and 10 µg/ml for embryos, 0.5; 0.9; 1;5 and 10 µg/ml for mollusks and 0.5; 1; 5; 10 µg/ml for A. salina. The lowest lethal concentration for the embryos and adult snails was 10 and 1 µg/ml, respectively. No toxicity to A. salina was found. The results show that modified usnic acid has increased solubility (100%) without losing its biological activity and may be a viable alternative for the control of B. glabrata.

  13. Assessment of toxicity of Moringa oleifera flower extract to Biomphalaria glabrata, Schistosoma mansoni and Artemia salina.

    Science.gov (United States)

    Rocha-Filho, Cláudio A A; Albuquerque, Lidiane P; Silva, Luanna R S; Silva, Patrícia C B; Coelho, Luana C B B; Navarro, Daniela M A F; Albuquerque, Monica C P A; Melo, Ana Maria M A; Napoleão, Thiago H; Pontual, Emmanuel V; Paiva, Patrícia M G

    2015-08-01

    This study reports the effect of an aqueous extract from Moringa oleifera Lam. flowers on Biomphalaria glabrata embryos and adults and on Schistosoma mansoni adult worms. The extract contains tannins, saponins, flavones, flavonols, xanthones, and trypsin inhibitor activity. The toxicity of the extract on Artemia salina larvae was also investigated to determine the safety of its use for schistosomiasis control. After incubation for 24h, the flower extract significantly (p<0.05) delayed the development of B. glabrata embryos and promoted mortality of adult snails (LC50: 2.37±0.5mgmL(-1)). Furthermore, treatment with the extract disrupted the development of embryos generated by snails, with most of them remaining in the blastula stage while control embryos were already in the gastrula stage. Flower extract killed A. salina larvae with a LC50 value (0.2±0.015mgmL(-1)) lower than that determined for snails. A small reduction (17%) in molluscicidal activity was detected when flower extract (2.37mgmL(-1)) was exposed to tropical environmental conditions (UVI index ranging from 1 to 14, temperature from 25 to 30°C, and 65% relative humidity). Toxicity to A. salina was also reduced (LC50 value of 0.28±0.01mgmL(-1)). In conclusion, M. oleifera flower extract had deleterious effects on B. glabrata adults and embryos. However, unrestricted use to control schistosomiasis should be avoided due to the toxicity of this extract on A. salina. PMID:25867917

  14. Assessment of toxicity of Moringa oleifera flower extract to Biomphalaria glabrata, Schistosoma mansoni and Artemia salina.

    Science.gov (United States)

    Rocha-Filho, Cláudio A A; Albuquerque, Lidiane P; Silva, Luanna R S; Silva, Patrícia C B; Coelho, Luana C B B; Navarro, Daniela M A F; Albuquerque, Monica C P A; Melo, Ana Maria M A; Napoleão, Thiago H; Pontual, Emmanuel V; Paiva, Patrícia M G

    2015-08-01

    This study reports the effect of an aqueous extract from Moringa oleifera Lam. flowers on Biomphalaria glabrata embryos and adults and on Schistosoma mansoni adult worms. The extract contains tannins, saponins, flavones, flavonols, xanthones, and trypsin inhibitor activity. The toxicity of the extract on Artemia salina larvae was also investigated to determine the safety of its use for schistosomiasis control. After incubation for 24h, the flower extract significantly (p<0.05) delayed the development of B. glabrata embryos and promoted mortality of adult snails (LC50: 2.37±0.5mgmL(-1)). Furthermore, treatment with the extract disrupted the development of embryos generated by snails, with most of them remaining in the blastula stage while control embryos were already in the gastrula stage. Flower extract killed A. salina larvae with a LC50 value (0.2±0.015mgmL(-1)) lower than that determined for snails. A small reduction (17%) in molluscicidal activity was detected when flower extract (2.37mgmL(-1)) was exposed to tropical environmental conditions (UVI index ranging from 1 to 14, temperature from 25 to 30°C, and 65% relative humidity). Toxicity to A. salina was also reduced (LC50 value of 0.28±0.01mgmL(-1)). In conclusion, M. oleifera flower extract had deleterious effects on B. glabrata adults and embryos. However, unrestricted use to control schistosomiasis should be avoided due to the toxicity of this extract on A. salina.

  15. Epigenetic modulation, stress and plasticity in susceptibility of the snail host, Biomphalaria glabrata, to Schistosoma mansoni infection.

    Science.gov (United States)

    Knight, Matty; Ittiprasert, Wannaporn; Arican-Goktas, Halime D; Bridger, Joanna M

    2016-06-01

    Blood flukes are the causative agent of schistosomiasis - a major neglected tropical disease that remains endemic in numerous countries of the tropics and sub-tropics. During the past decade, a concerted effort has been made to control the spread of schistosomiasis, using a drug intervention program aimed at curtailing transmission. These efforts notwithstanding, schistosomiasis has re-emerged in southern Europe, raising concerns that global warming could contribute to the spread of this disease to higher latitude countries where transmission presently does not take place. Vaccines against schistosomiasis are not currently available and reducing transmission by drug intervention programs alone does not prevent reinfection in treated populations. These challenges have spurred awareness that new interventions to control schistosomiasis are needed, especially since the World Health Organization hopes to eradicate the disease by 2025. For one of the major species of human schistosomes, Schistosoma mansoni, the causative agent of hepatointestinal schistosomiasis in Africa and the Western Hemisphere, freshwater snails of the genus Biomphalaria serve as the obligate intermediate host of this parasite. To determine mechanisms that underlie parasitism by S. mansoni of Biomphalaria glabrata, which might be manipulated to block the development of intramolluscan larval stages of the parasite, we focused effort on the impact of schistosome infection on the epigenome of the snail. Results to date reveal a complex relationship, manifested by the ability of the schistosome to manipulate the snail genome, including the expression of specific genes. Notably, the parasite subverts the stress response of the host to ensure productive parasitism. Indeed, in isolates of B. glabrata native to central and South America, susceptible to infection with S. mansoni, the heat shock protein 70 (Bg-HSP70) gene of this snail is rapidly relocated in the nucleus and transcribed to express HSP70

  16. Carbohydrate metabolism alterations in Biomphalaria glabrata infected with Schistosoma mansoni and exposed to Euphorbia splendens var. hislopii latex

    OpenAIRE

    Clélia Christina Mello-Silva; Mônica Magno Vilar; Maurício Carvalho Vasconcellos; Jairo Pinheiro; Maria de Lurdes de A Rodrigues

    2010-01-01

    This paper evaluates the alterations in the glycogen content of tissues (digestive gland and cephalopedal mass) and glucose in the haemolymph of Biomphalaria glabrata BH strain infected with Schistosoma mansoni BH strain and exposed to the latex of Euphorbia splendens var. hislopii. A reduction in the glycogen deposits was observed in infected snails exposed and not exposed to latex. However, the exposure to latex caused a greater depletion of the glycogen levels in both sites analysed, espec...

  17. Rheotaxis of Biomphalaria glabrata on vertical substrates and its role in the recolonization of habitats treated with molluscicides

    OpenAIRE

    P. Jurberg; C. L. P. A. Coelho da Silva; M. G. M. Barreto; Soares, M. S.

    1988-01-01

    The authors observed specimens of Biomphalaria glabrata climbing up the vertical wall of a ditch against the current. The snails that showed this behavior during application of a molluscicide in the breeding site survived and probably played a role in repopulation, which was observed three months later. These observations motivated field and laboratory investigations which led the authors to conclude that: a) this species is able to climb vertical surfaces both in field and laboratory situati...

  18. Controlled chaos of polymorphic mucins in a metazoan parasite (Schistosoma mansoni) interacting with its invertebrate host (Biomphalaria glabrata).

    OpenAIRE

    Emmanuel Roger; Christoph Grunau; Pierce, Raymond J.; Hirohisa Hirai; Benjamin Gourbal; Richard Galinier; Rémi Emans; Cesari, Italo M.; Céline Cosseau; Guillaume Mitta

    2008-01-01

    International audience Invertebrates were long thought to possess only a simple, effective and hence non-adaptive defence system against microbial and parasitic attacks. However, recent studies have shown that invertebrate immunity also relies on immune receptors that diversify (e.g. in echinoderms, insects and mollusks (Biomphalaria glabrata)). Apparently, individual or population-based polymorphism-generating mechanisms exists that permit the survival of invertebrate species exposed to p...

  19. 3D-ultrastructure, functions and stress responses of gastropod (Biomphalaria glabrata rhogocytes.

    Directory of Open Access Journals (Sweden)

    Maria Kokkinopoulou

    Full Text Available Rhogocytes are pore cells scattered among the connective tissue of different body parts of gastropods and other molluscs, with great variation in their number, shape and size. They are enveloped by a lamina of extracellular matrix. Their most characteristic feature is the "slit apparatus", local invaginations of the plasma membrane bridged by cytoplasmic bars, forming slits of ca. 20 nm width. A slit diaphragm creates a molecular sieve with permeation holes of 20×20 nm. In blue-blooded gastropods, rhogocytes synthesize and secrete the respiratory protein hemocyanin, and it has been proposed-though not proven-that in the rare red-blooded snail species they might synthesize and secrete the hemoglobin. However, the cellular secretion pathway for respiratory proteins, and the functional role(s of the enigmatic rhogocyte slit apparatus are still unclear. Additional functions for rhogocytes have been proposed, notably a role in protein uptake and degradation, and in heavy metal detoxification. Here we provide new structural and functional information on the rhogocytes of the red-blooded freshwater snail Biomphalaria glabrata. By in situ hybridization of mantle tissues, we prove that rhogocytes indeed synthesize hemoglobin. By electron tomography, the first three dimensional (3D reconstructions of the slit apparatus are provided, showing detail of highly dense material in the cytoplasmic bars close to the slits. By immunogold labelling, we collected evidence that a major component of this material is actin. By genome databank mining, the complete sequence of a B. glabrata nephrin was obtained, and localized to the rhogocytes by immunofluorescence microscopy. The presence of both proteins fit the ultrastructure-based hypothesis that rhogocytes are related to mammalian podocytes and insect nephrocytes. Reactions of the rhogocytes to deprivation of food and cadmium toxification are also documented, and a possible secretion pathway of newly synthesized

  20. Evaluation of the mitochondrial system in the gonad-digestive gland complex of Biomphalaria glabrata (Mollusca, Gastropoda) after infection by Echinostoma paraensei (Trematoda, Echinostomatidae).

    Science.gov (United States)

    Tunholi, Victor Menezes; Tunholi-Alves, Vinícius Menezes; Santos, Anderson Teixeira; Garcia, Juberlan da Silva; Maldonado, Arnaldo; da-Silva, Wagner Seixas; Rodrigues, Maria de Lurdes de Azevedo; Pinheiro, Jairo

    2016-05-01

    The effect of infection by Echinostoma paraensei on the mitochondrial physiology of Biomphalaria glabrata was investigated after exposure to 50 miracidia. The snails were dissected one, two, three and four weeks after infection for collection and mechanical permeabilization of the gonad-digestive gland (DGG) complex. The results obtained indicate that prepatent infection by this echinostomatid fluke significantly suppresses the phosphorylation state (respiratory state 3) and basal oxygen consumption of B. glabrata, demonstrating that the infection reduces the ability of the intermediate host to carry out aerobic oxidative reactions. Additionally, relevant variations related to the uncoupled mitochondrial (state 3u) of B. glabrata infected by E. paraensei were observed. Four weeks after exposure, a significant reduction in mitochondrial oxygen consumption after addition of ADP (3.68±0.26pmol O2/mg proteins) was observed in the infected snails in comparison with the respective control group (5.14±0.25). In the uncoupled state, the infected snails consumed about 62% less oxygen than the infected snails (7.87±0.84pmol O2/mg proteins) in the same period. These results demonstrate a reduction in oxidative decarboxylation rate of the tricarboxylic acid cycle and faster anaerobic degradation of carbohydrates in the infected snails. The possible mechanisms that explain this new metabolic condition in the infected organisms are discussed. PMID:27079167

  1. Steroid Androgen Exposure during Development Has No Effect on Reproductive Physiology of Biomphalaria glabrata.

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    Satwant Kaur

    Full Text Available Gastropod mollusks have been proposed as alternative models for male reproductive toxicity testing, due to similarities in their reproductive anatomy compared to mammals, together with evidence that endocrine disrupting chemicals can cause effects in some mollusks analogous to those seen in mammals. To test this hypothesis, we used the freshwater pulmonate snail, Biomphalaria glabrata, for which various genetic tools and a draft genome have recently become available, to investigate the effects of two steroid androgens on the development of mollusk secondary sexual organs. Here we present the results of exposures to two potent androgens, the vertebrate steroid; 5α-dihydrotestosterone (DHT and the pharmaceutical anabolic steroid; 17α-methyltestosterone (MT, under continuous flow-through conditions throughout embryonic development and up to sexual maturity. Secondary sexual gland morphology, histopathology and differential gene expression analysis were used to determine whether steroid androgens stimulated or inhibited organ development. No significant differences between tissues from control and exposed snails were identified, suggesting that these androgens elicited no biologically detectable response normally associated with exposure to androgens in vertebrate model systems. Identifying no effect of androgens in this mollusk is significant, not only in the context of the suitability of mollusks as alternative model organisms for testing vertebrate androgen receptor agonists but also, if applicable to other similar mollusks, in terms of the likely impacts of androgens and anti-androgenic pollutants present in the aquatic environment.

  2. Steroid Androgen Exposure during Development Has No Effect on Reproductive Physiology of Biomphalaria glabrata.

    Science.gov (United States)

    Kaur, Satwant; Baynes, Alice; Lockyer, Anne E; Routledge, Edwin J; Jones, Catherine S; Noble, Leslie R; Jobling, Susan

    2016-01-01

    Gastropod mollusks have been proposed as alternative models for male reproductive toxicity testing, due to similarities in their reproductive anatomy compared to mammals, together with evidence that endocrine disrupting chemicals can cause effects in some mollusks analogous to those seen in mammals. To test this hypothesis, we used the freshwater pulmonate snail, Biomphalaria glabrata, for which various genetic tools and a draft genome have recently become available, to investigate the effects of two steroid androgens on the development of mollusk secondary sexual organs. Here we present the results of exposures to two potent androgens, the vertebrate steroid; 5α-dihydrotestosterone (DHT) and the pharmaceutical anabolic steroid; 17α-methyltestosterone (MT), under continuous flow-through conditions throughout embryonic development and up to sexual maturity. Secondary sexual gland morphology, histopathology and differential gene expression analysis were used to determine whether steroid androgens stimulated or inhibited organ development. No significant differences between tissues from control and exposed snails were identified, suggesting that these androgens elicited no biologically detectable response normally associated with exposure to androgens in vertebrate model systems. Identifying no effect of androgens in this mollusk is significant, not only in the context of the suitability of mollusks as alternative model organisms for testing vertebrate androgen receptor agonists but also, if applicable to other similar mollusks, in terms of the likely impacts of androgens and anti-androgenic pollutants present in the aquatic environment.

  3. A Novel Bacterial Pathogen of Biomphalaria glabrata: A Potential Weapon for Schistosomiasis Control?

    Science.gov (United States)

    Duval, David; Galinier, Richard; Mouahid, Gabriel; Toulza, Eve; Allienne, Jean François; Portela, Julien; Calvayrac, Christophe; Rognon, Anne; Arancibia, Nathalie; Mitta, Guillaume; Théron, André; Gourbal, Benjamin

    2015-01-01

    Background Schistosomiasis is the second-most widespread tropical parasitic disease after malaria. Various research strategies and treatment programs for achieving the objective of eradicating schistosomiasis within a decade have been recommended and supported by the World Health Organization. One of these approaches is based on the control of snail vectors in endemic areas. Previous field studies have shown that competitor or predator introduction can reduce snail numbers, but no systematic investigation has ever been conducted to identify snail microbial pathogens and evaluate their molluscicidal effects. Methodology/Principal findings In populations of Biomphalaria glabrata snails experiencing high mortalities, white nodules were visible on snail bodies. Infectious agents were isolated from such nodules. Only one type of bacteria, identified as a new species of Paenibacillus named Candidatus Paenibacillus glabratella, was found, and was shown to be closely related to P. alvei through 16S and Rpob DNA analysis. Histopathological examination showed extensive bacterial infiltration leading to overall tissue disorganization. Exposure of healthy snails to Paenibacillus-infected snails caused massive mortality. Moreover, eggs laid by infected snails were also infected, decreasing hatching but without apparent effects on spawning. Embryonic lethality was correlated with the presence of pathogenic bacteria in eggs. Conclusions/Significance This is the first account of a novel Paenibacillus strain, Ca. Paenibacillus glabratella, as a snail microbial pathogen. Since this strain affects both adult and embryonic stages and causes significant mortality, it may hold promise as a biocontrol agent to limit schistosomiasis transmission in the field. PMID:25719489

  4. Steroid Androgen Exposure during Development Has No Effect on Reproductive Physiology of Biomphalaria glabrata

    Science.gov (United States)

    Lockyer, Anne E.; Routledge, Edwin J.; Jones, Catherine S.; Noble, Leslie R.; Jobling, Susan

    2016-01-01

    Gastropod mollusks have been proposed as alternative models for male reproductive toxicity testing, due to similarities in their reproductive anatomy compared to mammals, together with evidence that endocrine disrupting chemicals can cause effects in some mollusks analogous to those seen in mammals. To test this hypothesis, we used the freshwater pulmonate snail, Biomphalaria glabrata, for which various genetic tools and a draft genome have recently become available, to investigate the effects of two steroid androgens on the development of mollusk secondary sexual organs. Here we present the results of exposures to two potent androgens, the vertebrate steroid; 5α-dihydrotestosterone (DHT) and the pharmaceutical anabolic steroid; 17α-methyltestosterone (MT), under continuous flow-through conditions throughout embryonic development and up to sexual maturity. Secondary sexual gland morphology, histopathology and differential gene expression analysis were used to determine whether steroid androgens stimulated or inhibited organ development. No significant differences between tissues from control and exposed snails were identified, suggesting that these androgens elicited no biologically detectable response normally associated with exposure to androgens in vertebrate model systems. Identifying no effect of androgens in this mollusk is significant, not only in the context of the suitability of mollusks as alternative model organisms for testing vertebrate androgen receptor agonists but also, if applicable to other similar mollusks, in terms of the likely impacts of androgens and anti-androgenic pollutants present in the aquatic environment. PMID:27448327

  5. A novel bacterial pathogen of Biomphalaria glabrata: a potential weapon for schistosomiasis control?

    Directory of Open Access Journals (Sweden)

    David Duval

    2015-02-01

    Full Text Available Schistosomiasis is the second-most widespread tropical parasitic disease after malaria. Various research strategies and treatment programs for achieving the objective of eradicating schistosomiasis within a decade have been recommended and supported by the World Health Organization. One of these approaches is based on the control of snail vectors in endemic areas. Previous field studies have shown that competitor or predator introduction can reduce snail numbers, but no systematic investigation has ever been conducted to identify snail microbial pathogens and evaluate their molluscicidal effects.In populations of Biomphalaria glabrata snails experiencing high mortalities, white nodules were visible on snail bodies. Infectious agents were isolated from such nodules. Only one type of bacteria, identified as a new species of Paenibacillus named Candidatus Paenibacillus glabratella, was found, and was shown to be closely related to P. alvei through 16S and Rpob DNA analysis. Histopathological examination showed extensive bacterial infiltration leading to overall tissue disorganization. Exposure of healthy snails to Paenibacillus-infected snails caused massive mortality. Moreover, eggs laid by infected snails were also infected, decreasing hatching but without apparent effects on spawning. Embryonic lethality was correlated with the presence of pathogenic bacteria in eggs.This is the first account of a novel Paenibacillus strain, Ca. Paenibacillus glabratella, as a snail microbial pathogen. Since this strain affects both adult and embryonic stages and causes significant mortality, it may hold promise as a biocontrol agent to limit schistosomiasis transmission in the field.

  6. Larvicidal Activity against Aedes aegypti and Molluscicidal Activity against Biomphalaria glabrata of Brazilian Marine Algae

    Science.gov (United States)

    Guedes, Elíca Amara Cecília; de Carvalho, Cenira M.; Ribeiro Junior, Karlos Antonio Lisboa; Lisboa Ribeiro, Thyago Fernando; de Barros, Lurdiana Dayse; de Lima, Maria Raquel Ferreira; Prado Moura, Flávia de Barros; Goulart Sant'Ana, Antônio Euzebio

    2014-01-01

    This study investigated the biological activities of five benthic marine algae collected from Northeastern Region of Brazil. The tested activities included larvicidal activity against Aedes aegypti, molluscicidal activity against Biomphalaria glabrata, and toxicity against Artemia salina. Extracts of Ulva lactuca (Chlorophyta), Padina gymnospora, Sargassum vulgare (Phaeophyta), Hypnea musciformis, and Digenea simplex (Rhodophyta) were prepared using different solvents of increasing polarity, including dichloromethane, methanol, ethanol, and water. Of the extracts screened, the dichloromethane extracts of H. musciformis and P. gymnospora exhibited the highest activities and were subjected to bioassay-guided fractionation in hexane and chloroform. The chloroform fractions of the P. gymnospora and H. musciformis extracts showed molluscicidal activity at values below 40 μg·mL−1 (11.1460 μg·mL−1 and 25.8689 μg·mL−1, resp.), and the chloroform and hexane fractions of P. gymnospora showed larvicidal activity at values below 40 μg·mL−1 (29.018 μg·mL−1 and 17.230 μg·mL−1, resp.). The crude extracts were not toxic to A. salina, whereas the chloroform and hexane fractions of P. gymnospora (788.277 μg·mL−1 and 706.990 μg·mL−1) showed moderate toxicity, indicating that the toxic compounds present in these algae are nonpolar. PMID:24688787

  7. Differential gene expression in haemocytes of the snail Biomphalaria glabrata: effects of Schistosoma mansoni infection.

    Science.gov (United States)

    Miller, A N; Raghavan, N; FitzGerald, P C; Lewis, F A; Knight, M

    2001-05-15

    Parasite encapsulation and destruction in Biomphalaria glabrata has been shown to involve the cellular component of the snail's internal defence system, the haemocytes. To identify genes involved in the immunobiology of these cells, we used the method of differential display reverse transcriptase polymerase chain reaction (DDRT-PCR) to investigate differential gene regulation in haemocytes isolated from Schistosoma mansoni exposed and unexposed snails. RNA isolated from circulating haemocytes from resistant snails (BS-90 stock), previously exposed to S. mansoni, was analysed using 12 different arbitrary primers in conjunction with an anchored Oligo d(T(11)CG) primer. Transcription profiles between haemocytes of parasite exposed and unexposed snails were compared and a total of 87 differentially regulated bands were identified and isolated. Of these, 65 bands were cloned and used as probes in Southern blots to show the presence of corresponding sequences in the snail genome. RT-PCR was performed to verify the regulation of these transcripts. DNA sequence analysis showed that the majority of the cloned sequences were novel, although a few showed a high degree of sequence similarity to other sequences in the DNA and protein databases. One of these included a differentially expressed transcript that showed a significant degree of sequence identity to E. coli transposase Tn5, an enzyme whose activity is normally associated with generating mobility and instability in the genome. PMID:11336750

  8. Gamma {sup 60} Co D L {sub 50/30} of Biomphalaria glabrata (Say, 1818)

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Elaine Barros da Costa; Melo, Ana Maria Mendonca de Albuquerque; Motta, Mauricy Alves da [Pernambuco Univ., Recife, PE (Brazil). Dept. de Biofisica e Radiobiologia

    1999-12-01

    The variation of resistance to {sup 60} Co gamma-rays of Biomphalaria glabrata was studied. A population of 480 mollusks was observed during 30 days - distributed in 8 groups of snails isolated and 8 groups of snails in colonies - after exposure (30 snails per group per dose) to increasing doses of gamma radiation. Doses of 10, 20 40, 60, 80, 160, 320 and 640 Gy from a Gamma-cell {sup 60} Co irradiator, were applied to the test groups and two groups control (non-irradiated) of snails - isolated and colony - were kept apart. After have been exposed, the snails were drew back to the aquaria where they were maintained before. The survival was estimated on a daily score of the alive animals in each group-dose, starting after the irradiation exposure day. As a result, the survival self-fertilization forms (DL{sub 50/30}=218.2 Gy) was found greater than in cross-fecundation forms. These data point to allow radio-resistance on the cross-fertilization forms - the sexual reproductive form - which is most found in nature. The lower radio-resistance of the cross-fertilization forms suggests the presence of some sex-linked hormonal factor related to this phenomenon. (author)

  9. Gamma 60 Co D L 50/30 of Biomphalaria glabrata (Say, 1818)

    International Nuclear Information System (INIS)

    The variation of resistance to 60 Co gamma-rays of Biomphalaria glabrata was studied. A population of 480 mollusks was observed during 30 days - distributed in 8 groups of snails isolated and 8 groups of snails in colonies - after exposure (30 snails per group per dose) to increasing doses of gamma radiation. Doses of 10, 20 40, 60, 80, 160, 320 and 640 Gy from a Gamma-cell 60 Co irradiator, were applied to the test groups and two groups control (non-irradiated) of snails - isolated and colony - were kept apart. After have been exposed, the snails were drew back to the aquaria where they were maintained before. The survival was estimated on a daily score of the alive animals in each group-dose, starting after the irradiation exposure day. As a result, the survival self-fertilization forms (DL50/30=218.2 Gy) was found greater than in cross-fecundation forms. These data point to allow radio-resistance on the cross-fertilization forms - the sexual reproductive form - which is most found in nature. The lower radio-resistance of the cross-fertilization forms suggests the presence of some sex-linked hormonal factor related to this phenomenon. (author)

  10. Influence of experimental illumination and seasonal variation on crossbreending mating in the snail Biomphalaria Glabrata

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    F. Pimentel-Souza

    1988-03-01

    Full Text Available The crossbreeding activities of the Schistosoma mansoni vector snail Biomphalaria glabrata were counted in a laboratory aquarium throughout the year under two regimes of 12h light: 12h dark from 7 A., M. to 10 P. M. Mating increased significantly in Authmn and Winter and just missed a significant inverse correlation with temperature and a direct one with locomotion. Other similar experiments were carried out to compare mating under various ilumination conditions in complete daily cycle measurements. Mating counts decreased under the regimes which submited snail to a total exposure of 12h light and 12 dark during a daily cycle in the following sequence: 12h light: 12h dark alternating hourly with light gradient, 12h light: 12h dark, 1h light: 1h dark and 12h dark: 12h light. Under two constant illuminations, the mating scored less than under the previous conditions, except under 12h light. Under darkeness the mating count was lower than light conditions. There was no way to differentiate the night and day rhythms of mating on different days in each regime, except for mating under 12h light: 12 dark alternating with light gradient, constant dark and 12h dark: 12h light conditions. Mating increased in certain light and temperature conditions, in wich the intensities, should have an optimum value.

  11. Dominant lethal effect of gamma radiation of 60Co in Biomphalaria glabrata (SAY, 1818)

    International Nuclear Information System (INIS)

    Germ cell mutations are used in ecotoxicological studies as biomarkers of population effects and indicators of ecological changes. Biomphalaria glabrata, a freshwater mollusk, is a good experimental model for biomonitoring studies due to its biological characteristics and the ecological importance of this invertebrate group. The dominant lethal test was established in B. glabrata for the detection of germ cell mutations. Results with chemical mutagens showed that this system is efficient, specific and sensitive in the evaluation of germ cell mutations induced by reference mutagens. In this work, the dominant lethal effects of gamma radiation of 60Co were studied. A preliminary experiment was done to establish the dose range and to estimate the chronology of spermatogenesis in B. glabrata. This estimate is possible because of the uniformity in response to ionizing radiation between germ cells at homologous stages of spermatogenesis in widely different species. In general, pre-meiotic germ cells are less sensitive to the induction of lethal dominant mutations than post-meiotic cells. This effect can be attributed to: young gametogenic cells - mitotically active - have greater repair ability from sub-lethal DNA damage and there is a selective elimination of the damaged cells. In our system: induction of lethal dominant mutations causes an increase in the frequency of malformations and, cytotoxic effect is displayed as a reduction in the crossing rates. Total duration of spermatogenesis was estimated in approximately 36 days, with the following distribution of stages: 1 to 13 days - spermatogonia, 14 to 20 days - spermatocytes, 21 to 36 days - spermatids and spermatozoa. Based on this chronology, irradiated wild-type snails with 2,5; 10 and 20Gy and crossed with non-irradiated albino snails after 7, 17, 23, 30 and 36 days. The frequencies of malformations in the heterozygous wild-type offspring of the nonirradiated albino snails were used as indicator of germ cell

  12. Molluscicide activity of the "Avelós" plant (Euphorbia tirucalli, L. ) on Biomphalaria glabrata, the mollusc vector of schistosomiasis

    OpenAIRE

    Pedro Jurberg; Januário Bispo Cabral Neto; Virgínia T. Schall

    1985-01-01

    An aqueous solution of the latex of Euphorbia tirucalli collected at sites receiving large amounts of sunlight showed molluscicide action on Biomphalaria glabrata, with LD50 obtained at the concentration of 28,0 ppm and LD90 at the concentration of 85,0 ppm. The toxicity of the product for fish was similar to that of Bayluscide and of copper sulfate used for comparison. However, the wide distribution of the plant, its easy propagation and the simple procedure for extraction of the active subs...

  13. Circulating Biomphalaria glabrata hemocyte subpopulations possess shared schistosome glycans and receptors capable of binding larval glycoconjugates.

    Science.gov (United States)

    Yoshino, Timothy P; Wu, Xiao-Jun; Gonzalez, Laura A; Hokke, Cornelis H

    2013-01-01

    Host lectin-like recognition molecules may play an important role in innate resistance in Biomphalaria glabrata snails to larval schistosome infection, thus implicating parasite-expressed glycans as putative ligands for these lectin receptors. While host lectins may utilize specific glycan structures for parasite recognition, it also has been hypothesized that the parasite may use this system to evade immune detection by mimicking naturally-expressed host glycans, resulting in reduced immunorecognition capacity. By employing immunocytochemical (ICC) and Western blot assays using schistosome glycan-specific monoclonal antibodies (mABs) we sought to identify specific glycan epitopes (glycotopes) shared in common between larval Schistosoma mansoni and B. glabrata hemocytes, the primary immune effector cells in snails. Results confirmed the presence of selected larval glycotopes on subpopulations of hemocytes by ICC and association with numerous hemocyte proteins by Western blot analyses, including a trimannosyl core N-glycan (TriMan), and two fucosylated lacdiNAc (LDN) variants, F-LDN and F-LDN-F. Snail strain differences were seen in the prevalence of constitutively expressed F-LDN on hemocytes, and in the patterns of protein immunoreactivity with these mABs. In contrast, there was little to no hemocyte reactivity with mABs for Lewis X (LeX), LDN, LDN-F or LDN-DF. When intact hemocytes were exposed to larval transformation products (LTPs), distinct cell subpopulations displayed weak (LeX, LDN-DF) to moderate (LDN, LDN-F) glycotope reactivity by ICC, including snail strain differences in the prevalence of LDN-reactive cellular subsets. Far-Western blot analyses of the hemocytes following exposure to larval transformation proteins (LTPs) also revealed multiple mAB-reactive hemocyte protein bands for LeX, LDN, LDN-F, and LDN-DF. These results demonstrate the existence of complex patterns of shared larval glycan constitutively expressed on hemocytes and their proteins

  14. Molluscicidal activity of Moringa oleiferaon Biomphalaria glabrata: integrated dynamics to the control of the snail host of Schistosoma mansoni

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    Cesar Luiz Pinto Ayres Coelho da Silva

    2013-10-01

    Full Text Available The ground seed of Moringa oleifera Lam., Moringaceae, has been evaluated for its molluscicidal activity against the snails Biomphalaria glabrata, Physa marmorata and Melanoides tuberculatus. The results show that M. oleifera is active against B. glabrata (LC50 0.419 g/l; LC90 1.021 g/l and P. marmorata (LC50 0.339 g/l; LC90 0.789 g/l but has no effect against M. tuberculatus. The great innovation of the use of M. oleifera, in addition to being innocuous to humans, is the present nutritional potential for humans and animals as well as providing an ecosystemic service as water purifier.

  15. The molluscicidal activity of the latex of Euphorbia splendens var. hislopii on Melanoides tuberculata (Thiaridae), a snail associated with habitats of Biomphalaria glabrata (Planorbidae)

    OpenAIRE

    Alexandre Giovanelli; Cesar Luiz Pinto Ayres Coelho da Silva; Luisa Medeiros; Maurício Carvalho Vasconcellos

    2001-01-01

    The use of the latex of Euphorbia splendens var. hislopii was considered as an effective control method for Biomphalaria glabrata in Sumidouro, Rio de Janeiro. However, the appearance and expansion of the snail Melanoides tuberculata since August 1997, with the concomitant reduction of the population of B. glabrata suggest that competitive exclusion might be taking place. Depending on the susceptibility of the thiarid to the E. splendens toxin, the natural control that is occurring could be i...

  16. Estudo quantitativo de metais presentes na hemolinfa de Biomphalaria glabrata (Gastropoda, infectadas e não infectadas com Schistosoma mansoni Quantitative study of metal present in the hemolymph of Biomphalaria glabrata (Gastropoda, infected and uninfected with Schistosoma mansoni

    Directory of Open Access Journals (Sweden)

    Marco Antonio Vasconcelos Santos

    2005-04-01

    Full Text Available Inicialmente, desenvolveu-se um estudo para quantificar e comparar as concentrações de alguns metais presentes em duas amostras de hemolinfa do caramujo Biomphalaria glabrata (infectados e não-infectados com Schistosoma mansoni. A espectrometria de emissão óptica com fonte de plasma induzido (ICP-OES, foi utilizada para analisar os metais nas duas amostras. Os metais estudados foram: alumínio, cálcio, cádmio, cobalto, cromo, cobre, ferro, potássio, magnésio, manganês, chumbo e zinco. Os resultados mostram que, a princípio, os metais não são fatores determinantes no processo de defesa desses organismos contra este parasita, quando presente nos seus tecidos.We conducted a preliminary study to quantify and compare two concentrations of the same metals present in the hemolymph of snail Biomphalaria glabrata. In this context, we used Induction Coupled Plasma Optical Emission Spectroscopy technique (ICP-OES, to analyze the metals in the two samples (snails infected and not infected with Schistosoma mansoni. The metals studied were: aluminum, calcium, cadmium, cobalt, chromium, copper, iron, potassium, magnesium, manganese, lead and zinc. Preliminary results showed that such metals are not involved in the defense of these organisms against the parasite, when present in their tissues.

  17. Evaluation of the molluscicidal potential of hydroalcoholic extracts of Jatropha gossypiifolia Linnaeus, 1753 on Biomphalaria glabrata (Say, 1818).

    Science.gov (United States)

    Pereira Filho, Adalberto Alves; França, Clícia Rosane Costa; Oliveira, Dorlam's da Silva; Mendes, Renato Juvino de Aragão; Gonçalves, José de Ribamar Santos; Rosa, Ivone Garros

    2014-01-01

    The action of extracts from the stem, leaves, and fruit of Jatropha gossypiifolia on Biomphalaria glabrata was studied by analyzing survival, feeding capacity and oviposition ability. The extracts were obtained by macerating the plant parts in 92% ethanol, which were then evaporated until a dry residue was obtained and phytochemically studied. The molluscicidal activity on B. glabrata was investigated using the procedures recommended by WHO (1965). The amount of food ingested and oviposition were measured during each experiment. The extract of leaves from J. gossypiifolia was shown to be a strong molluscicidal agent, causing 100% mortality of B. glabrata, even in the lowest concentration tested, of 25 ppm. Regarding the fruit extract, there was variation in the mortality, depending on the concentration used (100, 75, 50 and 25 ppm). The snails that were in contact with the fruit extract had significant reduction in feeding and number of embryos in comparison to the control. The stem extract did not present molluscicidal activity nor had any influence on the feeding and oviposition abilities of B. glabrata, in the concentrations tested. In conclusion, the extracts of leaves and fruits of J. gossypiifolia investigated in this work show molluscicidal effect and may be sources of useful compounds for the schistosomiasis control. PMID:25351545

  18. Developmental toxicity, acute toxicity and mutagenicity testing in freshwater snails Biomphalaria glabrata (Mollusca: Gastropoda) exposed to chromium and water samples.

    Science.gov (United States)

    Tallarico, Lenita de Freitas; Borrely, Sueli Ivone; Hamada, Natália; Grazeffe, Vanessa Siqueira; Ohlweiler, Fernanda Pires; Okazaki, Kayo; Granatelli, Amanda Tosatte; Pereira, Ivana Wuo; Pereira, Carlos Alberto de Bragança; Nakano, Eliana

    2014-12-01

    A protocol combining acute toxicity, developmental toxicity and mutagenicity analysis in freshwater snail Biomphalaria glabrata for application in ecotoxicological studies is described. For acute toxicity testing, LC50 and EC50 values were determined; dominant lethal mutations induction was the endpoint for mutagenicity analysis. Reference toxicant potassium dichromate (K2Cr2O7) was used to characterize B. glabrata sensitivity for toxicity and cyclophosphamide to mutagenicity testing purposes. Compared to other relevant freshwater species, B. glabrata showed high sensitivity: the lowest EC50 value was obtained with embryos at veliger stage (5.76mg/L). To assess the model applicability for environmental studies, influent and effluent water samples from a wastewater treatment plant were evaluated. Gastropod sensitivity was assessed in comparison to the standardized bioassay with Daphnia similis exposed to the same water samples. Sampling sites identified as toxic to daphnids were also detected by snails, showing a qualitatively similar sensitivity suggesting that B. glabrata is a suitable test species for freshwater monitoring. Holding procedures and protocols implemented for toxicity and developmental bioassays showed to be in compliance with international standards for intra-laboratory precision. Thereby, we are proposing this system for application in ecotoxicological studies.

  19. Developmental toxicity, acute toxicity and mutagenicity testing in freshwater snails Biomphalaria glabrata (Mollusca: Gastropoda) exposed to chromium and water samples.

    Science.gov (United States)

    Tallarico, Lenita de Freitas; Borrely, Sueli Ivone; Hamada, Natália; Grazeffe, Vanessa Siqueira; Ohlweiler, Fernanda Pires; Okazaki, Kayo; Granatelli, Amanda Tosatte; Pereira, Ivana Wuo; Pereira, Carlos Alberto de Bragança; Nakano, Eliana

    2014-12-01

    A protocol combining acute toxicity, developmental toxicity and mutagenicity analysis in freshwater snail Biomphalaria glabrata for application in ecotoxicological studies is described. For acute toxicity testing, LC50 and EC50 values were determined; dominant lethal mutations induction was the endpoint for mutagenicity analysis. Reference toxicant potassium dichromate (K2Cr2O7) was used to characterize B. glabrata sensitivity for toxicity and cyclophosphamide to mutagenicity testing purposes. Compared to other relevant freshwater species, B. glabrata showed high sensitivity: the lowest EC50 value was obtained with embryos at veliger stage (5.76mg/L). To assess the model applicability for environmental studies, influent and effluent water samples from a wastewater treatment plant were evaluated. Gastropod sensitivity was assessed in comparison to the standardized bioassay with Daphnia similis exposed to the same water samples. Sampling sites identified as toxic to daphnids were also detected by snails, showing a qualitatively similar sensitivity suggesting that B. glabrata is a suitable test species for freshwater monitoring. Holding procedures and protocols implemented for toxicity and developmental bioassays showed to be in compliance with international standards for intra-laboratory precision. Thereby, we are proposing this system for application in ecotoxicological studies. PMID:25259848

  20. Molluscicide activity of the "Avelós" plant (Euphorbia tirucalli, L. on Biomphalaria glabrata, the mollusc vector of schistosomiasis

    Directory of Open Access Journals (Sweden)

    Pedro Jurberg

    1985-12-01

    Full Text Available An aqueous solution of the latex of Euphorbia tirucalli collected at sites receiving large amounts of sunlight showed molluscicide action on Biomphalaria glabrata, with LD50 obtained at the concentration of 28,0 ppm and LD90 at the concentration of 85,0 ppm. The toxicity of the product for fish was similar to that of Bayluscide and of copper sulfate used for comparison. However, the wide distribution of the plant, its easy propagation and the simple procedure for extraction of the active substance, which is biodegradable, favor "avelós" as a promising agent in the control of schistosomiasis.Uma solução aquosa de Euphorbia tirucalli (avelós coletada em locais ensolarados mostrou atividade moluscicida para Biomphalaria glabrata obtendo-se a LD50 a uma concentração de 28,0 ppm e a LD90 a 85,0 ppm. A toxicidade do produto para peixes foi similar a de Bayluscide e sulfato de cobre testados comparativamente. Pela larga distribuição da planta e sua fácil propagação e extração da substância ativa, e pela ausência de efeito residual, a planta pode ser considerada como promissora para testes de campo em locais restritos.

  1. Radioprotective effect of the extract of Ziziphus joazeiro and Anacardium occidentale on embryos of Biomphalaria glabrata submitted to ionizing radiation

    International Nuclear Information System (INIS)

    Electromagnetic radiations are energies that can be classified as non-ionizing and ionizing. This type of energy is propagated by a material medium and the vacuum. The important characteristic of ionizing radiation is the localized release of large amounts of energy. The biological effects of radiation result principally from damage to DNA, which is the critical target. Given these harmful effects caused by radiation highlights the importance of acquiring knowledge about the radioprotective substance, because they act to protect the living tissue, decreasing the damage he caused by the effects of radiation. In this study we investigated the radioprotective effect of extract hydroalcoholic of Ziziphus joazeiro and Anacardium occidentale on embryos of Biomphalaria glabrata. The embryos of Biomphalaria glabrata pigmented were divided into 18 groups of 100 specimens. The experimental groups were exposed to the extracts at a concentration of 200 ppm and then irradiated. For irradiation, we used a source of 60Co (Gammacell of Radionics Labs. Dose rate = 4.359 Gy/h). The viability of the embryos was examined using a stereoscopic microscope and statistical analysis was performed using the test Student-Newman-Keuls and χ2. Our results showed that the extracts of hydroalcoholic Ziziphus joazeiro showed radioprotective effect and that the aqueous extract of the bark of Anacardium occidentale exhibited a reduction in its embryotoxic effect. (author)

  2. Radioprotective effect of the extract of Ziziphus joazeiro and Anacardium occidentale on embryos of Biomphalaria glabrata submitted to ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Siqueira, Williams N.; Silva, Luanna R.S.; Silva, Edvane B. [Universidade Federal de Pernambuco (DEN/UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear. Grupo de Estudos em Radioprotecao e Radioecologia; Silva, Ronaldo C. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Genetica; Lacerda, Laila B.N.; Silva, Hianna A.M.F.; Santos, Mariana L.O.; Sa, Jose L.F.; Melo, Ana M.M.A. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de de Biofisica e Radiobiologia. Lab. de Radiobiologia

    2011-07-01

    Electromagnetic radiations are energies that can be classified as non-ionizing and ionizing. This type of energy is propagated by a material medium and the vacuum. The important characteristic of ionizing radiation is the localized release of large amounts of energy. The biological effects of radiation result principally from damage to DNA, which is the critical target. Given these harmful effects caused by radiation highlights the importance of acquiring knowledge about the radioprotective substance, because they act to protect the living tissue, decreasing the damage he caused by the effects of radiation. In this study we investigated the radioprotective effect of extract hydroalcoholic of Ziziphus joazeiro and Anacardium occidentale on embryos of Biomphalaria glabrata. The embryos of Biomphalaria glabrata pigmented were divided into 18 groups of 100 specimens. The experimental groups were exposed to the extracts at a concentration of 200 ppm and then irradiated. For irradiation, we used a source of {sup 60}Co (Gammacell of Radionics Labs. Dose rate = 4.359 Gy/h). The viability of the embryos was examined using a stereoscopic microscope and statistical analysis was performed using the test Student-Newman-Keuls and {chi}{sup 2}. Our results showed that the extracts of hydroalcoholic Ziziphus joazeiro showed radioprotective effect and that the aqueous extract of the bark of Anacardium occidentale exhibited a reduction in its embryotoxic effect. (author)

  3. Biomphalaria glabrata transcriptome: cDNA microarray profiling identifies resistant- and susceptible-specific gene expression in haemocytes from snail strains exposed to Schistosoma mansoni

    Directory of Open Access Journals (Sweden)

    Rollinson David

    2008-12-01

    Full Text Available Abstract Background Biomphalaria glabrata is an intermediate snail host for Schistosoma mansoni, one of the important schistosomes infecting man. B. glabrata/S. mansoni provides a useful model system for investigating the intimate interactions between host and parasite. Examining differential gene expression between S. mansoni-exposed schistosome-resistant and susceptible snail lines will identify genes and pathways that may be involved in snail defences. Results We have developed a 2053 element cDNA microarray for B. glabrata containing clones from ORESTES (Open Reading frame ESTs libraries, suppression subtractive hybridization (SSH libraries and clones identified in previous expression studies. Snail haemocyte RNA, extracted from parasite-challenged resistant and susceptible snails, 2 to 24 h post-exposure to S. mansoni, was hybridized to the custom made cDNA microarray and 98 differentially expressed genes or gene clusters were identified, 94 resistant-associated and 4 susceptible-associated. Quantitative PCR analysis verified the cDNA microarray results for representative transcripts. Differentially expressed genes were annotated and clustered using gene ontology (GO terminology and Kyoto Encyclopaedia of Genes and Genomes (KEGG pathway analysis. 61% of the identified differentially expressed genes have no known function including the 4 susceptible strain-specific transcripts. Resistant strain-specific expression of genes implicated in innate immunity of invertebrates was identified, including hydrolytic enzymes such as cathepsin L, a cysteine proteinase involved in lysis of phagocytosed particles; metabolic enzymes such as ornithine decarboxylase, the rate-limiting enzyme in the production of polyamines, important in inflammation and infection processes, as well as scavenging damaging free radicals produced during production of reactive oxygen species; stress response genes such as HSP70; proteins involved in signalling, such as importin 7

  4. Analysis of toxicity of Anacardium occidentale L. extract submitted to ionizing radiation on embryos of Biomphalaria glabrata and Artemia salina

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Hianna A.M.F.; Sa, Jose L.F.; Lima, Claudia S.A.; Amancio, Francisco F.; Melo, Ana M.M.A., E-mail: hiannaamfs@gmail.com, E-mail: luismuma6@gmail.com, E-mail: claudia.salima@gmail.com, E-mail: amancioff@bol.com.br, E-mail: amdemelo@hotmail.com [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Biofisica e Radiobiologia; Ribeiro, Luanna R.S.; Santos, Gustavo H.F.; Silva, Edvane B., E-mail: luannaribeiro_lua@hotmail.com, E-mail: santosghf@hotmail.com, E-mail: edvborges@yahoo.com.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear. Grupo de Estudos em Radioprotecao e Radioecologia

    2013-07-01

    The use of gamma radiation as a sterilization method for herbs, herbal medicines and foods, shows positive results regarding the retention of such products, economy and safety of the method. However, it is known that this method of processing plant material can cause chemical changes in these products related to the type of material, its components and the dose received. Evaluated, in the present study, the action of gamma radiation as a modifier of toxicity extract of Anacardium occidentale Linn. To evaluate the toxicity of the extract irradiated at doses of 5.0, 7.5 and 10.0 kGy and concentrations of 250, 500 and 1000 mg/L was used bioassays with Artemia salina and Biomphalaria glabrata. For the test to A. salina, 520 specimens were used divided into groups of 10 larvae. For the bioassay with B. glabrata, 3900 specimens were used divided into groups of, approximately, 100 embryos. Larvae of A. salina and embryos were subjected to extracts irradiated and unirradiated for 24 hours. The bioassay with A. salina, showed a decrease, compared to extract unirradiated and irradiated at doses of 5.0 and 7.5 kGy, of extract irradiated with 10 kGy, where the mortality did not differ from the control group. In tests with embryos was observed an increase in the toxicity of the extract at a dose of 7.5 kGy and a decrease in the dose of 10.0 kGy. The radiation promoted changes in the toxicity of leaves extracts of Anacardium occidentale Linn. on embryos of Biomphalaria glabrata and Artemia salina. (author)

  5. Transmission of Schistosoma mansoni under experimental conditions using the bovine - Biomphalaria glabrata - bovine model Transmissão do Schistosoma mansoni em condições experimentais, usando o modelo bovino - Biomphalaria glabrata - bovino

    Directory of Open Access Journals (Sweden)

    Celina M. Modena

    1993-02-01

    Full Text Available Three calves experimentally infected with Schistosoma mansoni, and passing viable eggs in feces, as well as 5 normal calves (coming from a non-endemic area for schistosomiasis kept as controls, were maintained in an enclosure (850 m² in area. In this enclosure, a tank with water received 500 laboratory reared Biomphalaria glabrata. All the control calves were infected for a period ranging from 79 to 202 days after the beginning of the experiment, and afterwards presented viable S. mansoni eggs in feces. The mean worm recovery was 555. The snail population increased throughout the experimental period, showing a high number of B. glabrata infected with S. mansoni (42% on average. According to the present study, bovine has been suggested as having potentially a role in the maintenance of the life cycle of S. mansoniTrês bezerros, experimentalmente infectados com Schistosoma mansoni e passando ovos viáveis nas fezes, bem como 5 bezerros normais, oriundos de área não endêmica para esquistossomose e usados como controles, foram mantidos em uma área fechada de 850 m². Nesta área, foram colocados em um tanque com água 500 caramujos Biomphalaria glabrata criados em laboratório. Todos os bezerros controles foram infectados por um período de 79 a 202 dias após o começo do experimento e, mais tarde, apresentaram ovos viáveis de S. mansoni nas fezes. A recuperação média de vermes foi de 538. A população de moluscos aumentou durante o período experimental, mostrando um número significativo de B. glabrata infectados com S. mansoni (42% em média. De acordo com o resultado do presente trabalho, que foi conduzido em condições experimentais, foi sugerido que bovinos tem, potencialmente, um papel na manutenção do ciclo vital do S. mansoni

  6. Estratégia competitiva entre Biomphalaria glabrata e Biomphalaria tenagophila: estudos de laboratório

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    Mairy Barbosa Loureiro dos Santos

    1989-01-01

    Full Text Available Observation about conhabitation among B. glabrata and B. tenagophila revealed a greater vulnerability of B. tenagophila population during the process of competition when its density was severaly decreased in 12 trials, moderate in 2 trials. It was higher than B. glabrata in only one trial. Some snail water chemical parameters analysed such as pH, alkalinity, conductivity and oxygen dissolve, an the viability rate of batch of eggs didn't give subsidy to explain the competition mechanism. The newly-born survival, in the situation of cohabitation, was low for both species. This reveals the existence of intra and interspecific competitive interacition. The fertility rate reduction of B. tenagophila during the cohabitation was considered as a cause of its exlusion. One of the factors that seems to have influenced the fertility rate was a possible wrong crossing.

  7. Effect of Niclosamide (Bayluscide WP 70 (R)), Anacardium occidentale hexane extract and Euphorbia splendens latex on behavior of Biomphalaria glabrata (Say, 1818), under laboratory conditions

    OpenAIRE

    Pedro Jurberg; Otília Sarquis; José Augusto A dos Santos; Regina da Conceição Reis Ferreira

    1995-01-01

    The repellent effect of the molluscicides Niclosamide (Bayluscide WP 70 (R)), Anacardium occidentale and the latex of Euphorbia splendens on Biomphalaria glabrata was observed through the investigation of the occurrence of escape behavior among molluscs that were exposed to dosages lower than the LD 50. The total number of individuals out of water among the surviving snails in the control group provided a "Natural Escape Index". The comparison between this total and the total number of surviv...

  8. Bases génétiques du polymorphisme de compatibilité dans l'interaction Schistosoma mansoni / Biomphalaria glabrata

    OpenAIRE

    Roger, Emmanuel

    2008-01-01

    The co-evolutionary dynamics that exist in certain invertebrate host / parasite interactions sometimes lead to a compatibility polymorphism, of which the molecular bases are unknown. To identify key molecules involved in this phenomenon in the Schistosoma mansoni / Biomphalaria glabrata model, we developed a comparative proteomics approach for the larval stages that interact with the invertebrate host. The qualitative and quantitative comparison of the proteomes of compatible and incompatible...

  9. Comparative study of the fecundity and fertility of Biomphalaria glabrata (Say, 1818 and Biomphalaria straminea (Dunker, 1848 in a laboratory through self-fertilization and cross-fertilization Estudo comparativo da fecundidade e fertilidade de Biomphalaria glabrata (Say, 1818 e Biomphalaria straminea (Dunker, 1848 em laboratório por autofecundação e fecundação cruzada

    Directory of Open Access Journals (Sweden)

    Marta Julia F.S. Costa

    2004-06-01

    Full Text Available The aim of this study was to compare the fecundity and fertility of B. glabrata and B. straminea by cross- and self-fertilization. To attain this objective, laboratory-raised strains of B. glabrata and B. straminea were used. The former originated from natural breeding grounds in the municipality Paulista, state of Pernambuco, Brazil. The latter originated from irrigation ditches in the municipality of Petrolândia, in the same state. Snail populations of B. glabrata and B. straminea were maintained for 240 days in laboratory. Their fecundity was evaluated by noting the number of egg-masses, eggs and eggs per mass. Their fertility was evaluated by the number of viable eggs and the hatching rate. B. straminea was markedly more fecund than B. glabrata through cross- and self-fertilization, namely: greater egg-mass; higher egg production and more eggs per mass. Regarding fertility, there seemed to be no preferential period for occlusion to occur or a trend in the rhythm of producing viable eggs.O objetivo deste trabalho foi comparar a fecundidade e fertilidade de Biomphalaria glabrata e Biomphalaria straminea em condições de laboratório considerando a autofecundação e a fecundação cruzada. Durante oito meses, foram registrados em laboratório, o número de cápsulas ovíferas (desovas, ovos por cápsula ovífera, ovos totais, taxa de eclosão e percentual de ovos férteis dos moluscos criados individualmente e agrupados. Foram utilizados exemplares de B. glabrata de Paulista, PE e B. straminea oriunda de Petrolândia, PE. As observações foram divididas por faixa etária no periódo de 0 a 240 dias. Os resultados obtidos neste trabalho mostram que B. straminea apresenta um potencial reprodutivo maior do que B. glabrata, tanto para moluscos criados em grupo quanto para os criados individualmentes. A comparação dos valores encontrados para fecundidade dentro da mesma espécie sugere que a autofecundação como estratégia reprodutiva,

  10. Padronização da técnica de marcação de caramujos Biomphalaria glabrata com radioestroncio Standardization of the technic of labeling Biomphalaria glabrata snails with radiostrontium

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    Miguel Archanjo Muniz Leal

    1982-06-01

    Full Text Available Caramujos Biomphalaria glabrata vetor da esquistossomose mansônica, utilizados em experiências de campo, nas quais se faz necessário sua identificação e/ou localização, devem ser marcados com radioestrôncio 85,89 ou 90. Sua marcação em laboratório deve ser procedida em aquários de vidro sem fundo de areia, temperatura de 26,5 ± 1ºC, pH ajustado ao valor encontrado no "habitat", aeração artificial, alimentação diária com pequenas porções de alface fresca e 25 ml de água desionizada por caramujo. O nível de atividade no caramujo pode ser estimado sabendo-se que para o tempo de marcação de 5 dias e atividades iniciais de 0,036 a 0,362 µCi/ml, a captação global para grupos de 10 caramujos está em torno de 84 ± 2% e que a marcação em água contendo cálcio, praticamente não se altera até concentrações de 50ppm. A sobrevida ao longo de nove semanas não foi influenciada pela presença de radioestrôncio no caramujo.The vector snail of schistosomiasis mansoni, Biomphalaria glabrata, when used in field experiments in which it is to be recovered and/or located, should be labeled with radiostrontium 85,89 or 90. The labeling in laboratory should be carried out in an artificially aerated aquarium with 25 ml of deionized water per snail, without sand at the bottom, at a temperature of 26.5 ± 1ºC, pH adjusted to the value found in the natural habitat, and the snails should be fed with small pieces of fresh lettuce. The level of snail activity can be estimated taking into account that, for a labeling time of 5 days and initial activities of 0.036 to 0.362 µCi/ml, the global uptake for groups of 10 snails is about 84 ± 2% and that labeling in calcium-containing water parctically does not change till a 50 ppm concentration. Survival along 9 weeks was not influenced by the presence of radiostrontium in the snail.

  11. Rheotaxis of Biomphalaria glabrata on vertical substrates and its role in the recolonization of habitats treated with molluscicides

    Directory of Open Access Journals (Sweden)

    P. Jurberg

    1988-06-01

    Full Text Available The authors observed specimens of Biomphalaria glabrata climbing up the vertical wall of a ditch against the current. The snails that showed this behavior during application of a molluscicide in the breeding site survived and probably played a role in repopulation, which was observed three months later. These observations motivated field and laboratory investigations which led the authors to conclude that: a this species is able to climb vertical surfaces both in field and laboratory situations; b the current of water, as a physical stimulus, is sufficient to trigger this behavior (rheotaxis; c rheotaxis on vertical surfaces depends on the presence of a necessarily moderate current; d there are indications that B. glabrata may undergo habituation with respect to rheotaxis on vertical walls, e the relationship between rheotaxis and habituation should be considered as a factor causing snail grouping in water bodies which may contribute to their localization in the field; f rheotaxis on vertical surfaces may facilitate population dispersal, and its occurrence should be considered when campaigns for the control of schistosomiasis transmission are planned. The authors present some proposals to avoid the manifestation of this behavior in some filed situations.Os autores observaram exemplares de Biomphalaria glabrata subindo contra corrente em uma parede vertical de uma vala, constatando que os caramujos que apresentavam esse comportamento durante a aplicação de miluscicida neste criadouro sobreviveram e, provavelmente, tiveram papel de repovoamento, que foi observado três meses após. Essas observações suscitaram investigações de campo e de laboratório, através das quais concluiram que: a esta espécie é capaz de subir em superfícies verticais em situações de campo e de laboratório; b a corrente da água enquanto estímulo físico, é suficiente para desencadear esse comportamento (reotaxia; c a reotaxia em superfícies verticais depende

  12. Comportamento de Biomphalaria glabrata (Say, 1818 como critério de toxicidade em ensaios biológicos com moluscicidas Behavior of Biomphalaria glabrata (Say, 1818 as a parameter of toxicity in biological assays with molluscicides

    Directory of Open Access Journals (Sweden)

    Otávio S. Pieri

    1981-06-01

    Full Text Available Visando à aplicação sistemática de parâmetros comportamentais como indicadores da ação tóxica de moluscicidas empregados no combate aos hospedeiros intermediários do Schistosoma mansoni, um procedimento para avaliação quantitativa do efeito de dose sobre o comprotamento de Biomphalaria glabrata foi desenvolvido, com base no paradigma recomendado pela O.M.S. para ensaios biológicos e envolvendo registro comportamental por cenematografia ocm lapso de tempo: caramujos com 5 7/8 ± 1/8 giros eram subemtidos a diferentes concentrações subletais de sulfato de cobre durante 24 horas e em seguida transferidos para recuperação em água destilada desionizada; a partir da análise dos registros foram computados (a a freqüência total de subidas à superfície por indivíduo, (b a frqüência total de saídas da água por indivíduo e (c a proporção média de indivíduos no terço superior do recipiente de teste. O método Litchfield-Wilcoxon foi empregaod para determinação de índices de referência (denominados "concentrações de efieto comportamental de 50%" ou CEC50 em relação a cada parâmetro, e os valores obtidos - (a 0,010, (b 0,006 e (c 0,029 ppm de cobre - não só evidenciaram a exeqüibilidade da aplicação sistemática de critérios comportamentais de toxidade, como se revelaram capazes de detectar o efieto tóxico do produto em concentrações muito infereiores às obtidas nas determinações convencionais de letalidade. Os dados também mostraram alterações na atividade dos caramujos em decorrência do ciclo de iluminação dia-noite. Embora o esclarecimento dos aspectos etológicos envolvidos no problema do controle químico do vetor dependa da análise das relações entre o indivíduo e seu ambiente natural, estudos de laboratório com mensurações acuradas de parâmetros relacionados a comportamentos de proteção podem fornecer subsídios relevantes a respeito.The possibility of using reliable behavioural

  13. Bioactivity Evaluation of Plant Extracts Used in Indigenous Medicine against the Snail, Biomphalaria glabrata, and the Larvae of Aedes aegypti

    Science.gov (United States)

    dos Santos, Edilson Alves; de Carvalho, Cenira M.; Costa, Ana L. S.; Conceição, Adilva S.; Moura, Flávia de B. Prado; Santana, Antônio Euzébio Goulart

    2012-01-01

    This investigation examined the molluscicidal and larvicidal activity of eight plants that are used in the traditional medicine of the Pankararé indigenous people in the Raso da Catarina region, Bahia state, Brazil. The tested plants were chosen based on the results of previous studies. Only those plants that were used either as insect repellents or to treat intestinal parasitic infections were included in the study. Crude extracts (CEs) of these plants were tested for their larvicidal activity (against Aedes aegypti larvae in the fourth instar) and molluscicidal activity (against the snail Biomphalaria glabrata). The plant species Scoparia dulcis and Helicteres velutina exhibited the best larvicidal activities (LC50 83.426 mg/L and LC50 138.896 mg/L, resp.), and Poincianella pyramidalis, Chenopodium ambrosoides, and Mimosa tenuiflora presented the best molluscicidal activities (LC50 0.94 mg/L, LC50 13.51 mg/L, and LC50 20.22 mg/L, resp.). As we used crude extracts as the tested materials, further study is warranted to isolate and purify the most active compounds. PMID:22194773

  14. Bioactivity Evaluation of Plant Extracts Used in Indigenous Medicine against the Snail, Biomphalaria glabrata, and the Larvae of Aedes aegypti

    Directory of Open Access Journals (Sweden)

    Edilson Alves dos Santos

    2012-01-01

    Full Text Available This investigation examined the molluscicidal and larvicidal activity of eight plants that are used in the traditional medicine of the Pankararé indigenous people in the Raso da Catarina region, Bahia state, Brazil. The tested plants were chosen based on the results of previous studies. Only those plants that were used either as insect repellents or to treat intestinal parasitic infections were included in the study. Crude extracts (CEs of these plants were tested for their larvicidal activity (against Aedes aegypti larvae in the fourth instar and molluscicidal activity (against the snail Biomphalaria glabrata. The plant species Scoparia dulcis and Helicteres velutina exhibited the best larvicidal activities (LC50 83.426 mg/L and LC50 138.896 mg/L, resp., and Poincianella pyramidalis, Chenopodium ambrosoides, and Mimosa tenuiflora presented the best molluscicidal activities (LC50 0.94 mg/L, LC50 13.51 mg/L, and LC50 20.22 mg/L, resp.. As we used crude extracts as the tested materials, further study is warranted to isolate and purify the most active compounds.

  15. Distribution and Schistosoma mansoni infection of Biomphalaria glabrata in different habitats in a rural area in the Jequitinhonha Valley, Minas Gerais, Brazil: environmental and epidemiological aspects

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    Helmut Kloos

    2004-11-01

    Full Text Available This paper examines the distribution and infection of Biomphalaria glabrata with Schistosoma mansoni in all aquatic snail habitats in a rural area in the state of Minas Gerais, Brazil, in relation to physico/biotic and behavioral factors. Snail and environmental surveys were carried out semi-annually between July 2001 and November 2002 at 106 sites. Collected snails were examined in the laboratory for infection. B. glabrata densities were highest in overflow ponds, irrigation ponds, springs, canals and wells, and lowest in fishponds and water tanks. Snail densities were higher during the hot, rainy season except for streams and canals and were statistically associated with the presence of fish, pollution, and vegetation density. Tilapia fish and an unidentified Diptera larva were found to be predators of B. glabrata but ducks were not. Twenty-four of the 25 infected snails were collected in 2001(1.4% infection rate and only one in 2002, after mass chemotherapy. The occurrence of B. glabrata in all 11 snail habitats both at and away from water contact sites studied indicates widespread risk of human infection in the study area. In spite of the strong association between B. glabrata and tilapia in fishponds we do not recommend its use in schistosomiasis control for ecological reasons and its relative inefficiency in streams and dams.

  16. The molluscicidal activity of the latex of Euphorbia splendens var. hislopii on Melanoides tuberculata (Thiaridae, a snail associated with habitats of Biomphalaria glabrata (Planorbidae

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    Alexandre Giovanelli

    2001-01-01

    Full Text Available The use of the latex of Euphorbia splendens var. hislopii was considered as an effective control method for Biomphalaria glabrata in Sumidouro, Rio de Janeiro. However, the appearance and expansion of the snail Melanoides tuberculata since August 1997, with the concomitant reduction of the population of B. glabrata suggest that competitive exclusion might be taking place. Depending on the susceptibility of the thiarid to the E. splendens toxin, the natural control that is occurring could be interrupted by the employment of the latex if the planorbid were less susceptible to the toxin. The aim of this study is to investigate the molluscicidal activity of the latex on M. tuberculata. We used 420 M. tuberculata, from Sumidouro. Fourteen different latex concentrations were tested using World Health Organization general methodology. Probit analysis was used for LD90 and LD50 determination. The LD50 was 3.57 mg/l and LD90 was 6.22 mg/l. At the highest concentration (10 mg/l there was no survival. No significant differences among replicas (chi2 = 8.31; gl = 13; p > 0.05 were found. The LD90 dose for M. tuberculata was 13.8 times greater than that for B. glabrata, so that the molluscicide in the presence of the thiarid may have a synergic effect on reduction of Biomphalaria populations.

  17. Production of Shistosoma mansoni cercariae by Biomphalaria glabrata from a focus in Belo Horizonte, Minas Gerais Produção de cercárias de Schistosoma mansoni por Biomphalaria glabrata de foco em Belo Horizonte, Minas Gerais

    Directory of Open Access Journals (Sweden)

    Cecília Pereira de Souza

    1994-12-01

    Full Text Available The snail density, levels of infection and the monthly production of Schistosoma mansoni cercariae by Biomphalaria glabrata were determined in a focus of Barreiro de Baixo (Belo Horizonte, MG, Brazil. During a period of 38 months (1984 to 1987 5,366 snails were collected of which 324 (6.03% were infected with S. mansoni. The total number of cercariae shed was 5,667,312. Each snail shed an average of 17,422 cercariae during the time that it was under study in the laboratory. The greatest longevity of infected snails was 218 days. Natural cure was observed in 42 (12.9% of the infected specimens about 130 days after collection. The average snail density in the focus during the period of study was 16.3 snails per scoop. The shedding of cercariae by snails collected from the field was compared with laboratory bred specimens infected in mass with the LE strain of S. mansoni from Belo Horizonte. The laboratory infected snails shed an average of 6,061 cercariae each, a value 2.8 times less than the field specimens due to a shorter life span. The prevalence of schistosomiasis in the focus was 14.3%.A densidade planorbídica, as taxas de infecção e a produção mensal de cercárias de Schistosoma mansoni por Biomphalaria glabrata, foram determinadas em foco do Barreiro de Baixo (Belo Horizonte MG, Brasil. Durante 38 meses, de 1984 a 1987, foram capturados 5.366 moluscos dentre os quais 324 (6,03% estavam infectados com o S. mansoni. O total de cercárias eliminadas foi de 5.667.312. Cada molusco eliminou em média 17.422 cercárias durante sua permanência no laboratório. A maior longevidade dos moluscos infectados foi de 218 dias. Foi observada a cura natural de 42 (12,9% dos exemplares infectados, após cerca de 130 dias de captura. A densidade planorbídica média, no foco durante esse período foi de 16,3 moluscos por conchada. A eliminação de cercárias pelos moluscos do campo foi comparada com a de exemplares criados no laboratório, infectados

  18. The role of behavior in the survival of Biomphalaria glabrata in biossays with the plant molluscicide Phytolacca dodecandra O papel do comportamento na sobrevivência de Biomphalaria glabrata submetida a bioensaios com o moluscicida vegetal Phytolacca dodecandra

    Directory of Open Access Journals (Sweden)

    P. Jurberg

    1988-03-01

    Full Text Available This work examines the role of behavior in the survival of Biomphalaria glabrata exposed to 25, 50 75 and 100 mgl-1 of Phytolacca dodecandra. Time-lapse cinematography was used to quantify accurately the following parameters: (a frequency of exits from the solution, (b time spent out of the solution and (c time elapsed until the first exit from the solution. These behavior patterns were statistically compared between surviving snails and those which later died. The proportion of surviving snails leaving the liquid medium was significantly higher than that of dying snails. In addition, the surviving group spent significantly more time out of the solution than the group which died, except for the 100 mgl-1 concentration. However, no significant difference was detected in the time elapsed until the first exit from the solution. It can be concluded that both the tendency to leave the P. dodecandra solutions, and the time spent out of them, contributed significantly to snail survival. Molluscicide bioassays should take into account the possibility that some behavior patterns of planorbids might contribute to the protection of the snails.Este trabalho investiga o papel do comportamento na sobrevivência de Biomphalaria glabarta exposta a 25, 50, 75 e 100 mgI-1 de Phytolacca dodecandra. Foi utilizada a técnica de cinematografia com lapso de tempo para quantificar acuradamente os seguintes parâmetros (a freqüência de saídas da solução, (b tempo de permanência fora da solução e (e tempo decorrido até a primeira saída da soluçao. Estes padrões comportamentais foram estatisticamente comparados no que se refere aos caramujos sobreviventes e aos que vieram a morrer. Dentre os camundongos que abandonaram o meio líquido, a proporção de sobreviventes foi significativamente maior que a de mortos. Além disso, um tempo significativamente maior de permanência fora da solução foi observado no grupo que sobreviveu, em relação ao grupo que veio

  19. Differential spatial repositioning of activated genes in Biomphalaria glabrata snails infected with Schistosoma mansoni

    OpenAIRE

    Arican-Goktas, HD; Ittiprasert, W; Bridger, JM; Knight, M.

    2014-01-01

    Schistosomiasis is an infectious disease infecting mammals as the definitive host and fresh water snails as the intermediate host. Understanding the molecular and biochemical relationship between the causative schistosome parasite and its hosts will be key to understanding and ultimately treating and/or eradicating the disease. There is increasing evidence that pathogens that have co-evolved with their hosts can manipulate their hosts' behaviour at various levels to augment an infection. Bact...

  20. Differential spatial repositioning of activated genes in Biomphalaria glabrata snails infected with Schistosoma mansoni.

    OpenAIRE

    Arican-Goktas, Halime D.; Wannaporn Ittiprasert; Joanna M Bridger; Matty Knight

    2014-01-01

    Schistosomiasis is an infectious disease infecting mammals as the definitive host and fresh water snails as the intermediate host. Understanding the molecular and biochemical relationship between the causative schistosome parasite and its hosts will be key to understanding and ultimately treating and/or eradicating the disease. There is increasing evidence that pathogens that have co-evolved with their hosts can manipulate their hosts' behaviour at various levels to augment an infection. Bact...

  1. Effects of Plagiorchis elegans (Digenea: Plagiorchiidae) infection of Biomphalaria glabrata (Pulmonata: Planorbidae) on a challenge infection with Schistosoma mansoni (Digenea: Schistosomatidae).

    Science.gov (United States)

    Zakikhani, M; Smith, J M; Rau, M E

    2003-02-01

    Prior exposure of Biomphalaria glabrata to the eggs of an incompatible digenean, Plagiorchis elegans, rendered this snail host less suitable to a compatible species, Schistosoma mansoni. Although P. elegans failed to develop patent infections in B. glabrata, it reduced the production of S. mansoni cercariae by 88%. Concomitantly, host attributes such as reproduction, growth, and survival were compromised. The effect of P. elegans infection was most severe among snails that, in addition, had developed patent schistosome infections. Although few S. mansoni cercariae were produced, egg production by B. glabrata was only 4% of control values. Furthermore, no doubly infected snails survived for more than 3 wk after patency, whereas controls experienced no mortality during the same time period. The above effects were attributable to the establishment and persistence of P. elegans sporocysts in the tissues of the incompatible snail host. Their indirect antagonistic interaction with thelarval stages of S. mansoni may be mediated, in part, through their long-term stimulation of the host's internal defense mechanisms. These findings are discussed with a view to use P. elegans and other plagiorchiid digeneans as agents in the biological control of snails and snail-borne diseases. PMID:12659305

  2. Aspectos ultraestruturais de hemócitos de Biomphalaria glabrata Say (1818) (Gastropoda: Planorbidae) analisados sob microscopia eletrônica de transmissão Ultrastructural aspects of hemocytes from Biomphalaria glabrata Say (1818) (Gastropoda: Planorbidae) analysed with transmission eletronic microscopy

    OpenAIRE

    Marco Antonio Vasconcelos Santos; José Antonio Picanço Diniz

    2009-01-01

    Os hemócitos do caramujo Biomphalaria glabrata, um importante transmissor do trematódeo Schistosoma mansoni no Brasil, foram coletados de especimens na região Bragantina, localizada a oeste do estado do Pará. Os hemócitos foram examinados por meio de microscopia eletrônica de transmissão. As células foram fixadas pelo método de rotina com o uso do tampão PHEM (PIPES, HEPES, EGTA e Magnésio). Foram descritos os aspectos ultra-estruturais celulares como inclusões citoplasmáticas limitadas por m...

  3. Aspectos ultraestruturais de hemócitos de Biomphalaria glabrata Say (1818 (Gastropoda: Planorbidae analisados sob microscopia eletrônica de transmissão Ultrastructural aspects of hemocytes from Biomphalaria glabrata Say (1818 (Gastropoda: Planorbidae analysed with transmission eletronic microscopy

    Directory of Open Access Journals (Sweden)

    Marco Antonio Vasconcelos Santos

    2009-09-01

    Full Text Available Os hemócitos do caramujo Biomphalaria glabrata, um importante transmissor do trematódeo Schistosoma mansoni no Brasil, foram coletados de especimens na região Bragantina, localizada a oeste do estado do Pará. Os hemócitos foram examinados por meio de microscopia eletrônica de transmissão. As células foram fixadas pelo método de rotina com o uso do tampão PHEM (PIPES, HEPES, EGTA e Magnésio. Foram descritos os aspectos ultra-estruturais celulares como inclusões citoplasmáticas limitadas por membranas, mitocôndrias, retículos endoplasmáticos e outros. As observações mostram que esse tampão possui a propriedade de preservação do citoesqueleto celular, apresentando bons resultados na preservação das estruturas dos hemócitos e suas organelas.The blood cells of the pulmonate snail Biomphalaria glabrata from the region of Bragantina in the state of Pará, an important vector of the trematode Schistosoma mansoni in Brazil, were collected and fixed by routine method with PHEM buffer and examined with transmission electron microscopy. Ultrastructural cellular aspects like cytoplasmic inclusions, mitochondrion, vesicles and others organelles are described. The buffer used resulted in good preservations of the hemocytes and their organelles.

  4. Estudo do crescimento de moluscos pertencentes a populações de Biomphalaria glabrata e B. tenagophila

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    Luiz A. Magalhães

    1969-01-01

    Full Text Available Os autores estudam, comparativamente o crescimento de duas populações de moluscos planorbídeos pertencentes às espécies B. glabrata e B. tenagophila. Concluem que não há diferença significativa entre o crescimento dos caramujos oriundos das populações estudadas.

  5. Altered Gene Expression in the Schistosome-Transmitting Snail Biomphalaria glabrata following Exposure to Niclosamide, the Active Ingredient in the Widely Used Molluscicide Bayluscide.

    Science.gov (United States)

    Zhang, Si-Ming; Buddenborg, Sarah K; Adema, Coen M; Sullivan, John T; Loker, Eric S

    2015-01-01

    In view of the call by the World Health Organization (WHO) for elimination of schistosomiasis as a public health problem by 2025, use of molluscicides in snail control to supplement chemotherapy-based control efforts is likely to increase in the coming years. The mechanisms of action of niclosamide, the active ingredient in the most widely used molluscicides, remain largely unknown. A better understanding of its toxicology at the molecular level will both improve our knowledge of snail biology and may offer valuable insights into the development of better chemical control methods for snails. We used a recently developed Biomphalaria glabrata oligonucleotide microarray (31K features) to investigate the effect of sublethal exposure to niclosamide on the transcriptional responses of the snail B. glabrata relative to untreated snails. Most of the genes highly upregulated following exposure of snails to niclosamide are involved in biotransformation of xenobiotics, including genes encoding cytochrome P450s (CYP), glutathione S-transferases (GST), and drug transporters, notably multi-drug resistance protein (efflux transporter) and solute linked carrier (influx transporter). Niclosamide also induced stress responses. Specifically, six heat shock protein (HSP) genes from three super-families (HSP20, HSP40 and HSP70) were upregulated. Genes encoding ADP-ribosylation factor (ARF), cAMP response element-binding protein (CREB) and coatomer, all of which are involved in vesicle trafficking in the Golgi of mammalian cells, were also upregulated. Lastly, a hemoglobin gene was downregulated, suggesting niclosamide may affect oxygen transport. Our results show that snails mount substantial responses to sublethal concentrations of niclosamide, at least some of which appear to be protective. The topic of how niclosamide's lethality at higher concentrations is determined requires further study. Given that niclosamide has also been used as an anthelmintic drug for decades and has been

  6. Altered Gene Expression in the Schistosome-Transmitting Snail Biomphalaria glabrata following Exposure to Niclosamide, the Active Ingredient in the Widely Used Molluscicide Bayluscide.

    Directory of Open Access Journals (Sweden)

    Si-Ming Zhang

    Full Text Available In view of the call by the World Health Organization (WHO for elimination of schistosomiasis as a public health problem by 2025, use of molluscicides in snail control to supplement chemotherapy-based control efforts is likely to increase in the coming years. The mechanisms of action of niclosamide, the active ingredient in the most widely used molluscicides, remain largely unknown. A better understanding of its toxicology at the molecular level will both improve our knowledge of snail biology and may offer valuable insights into the development of better chemical control methods for snails. We used a recently developed Biomphalaria glabrata oligonucleotide microarray (31K features to investigate the effect of sublethal exposure to niclosamide on the transcriptional responses of the snail B. glabrata relative to untreated snails. Most of the genes highly upregulated following exposure of snails to niclosamide are involved in biotransformation of xenobiotics, including genes encoding cytochrome P450s (CYP, glutathione S-transferases (GST, and drug transporters, notably multi-drug resistance protein (efflux transporter and solute linked carrier (influx transporter. Niclosamide also induced stress responses. Specifically, six heat shock protein (HSP genes from three super-families (HSP20, HSP40 and HSP70 were upregulated. Genes encoding ADP-ribosylation factor (ARF, cAMP response element-binding protein (CREB and coatomer, all of which are involved in vesicle trafficking in the Golgi of mammalian cells, were also upregulated. Lastly, a hemoglobin gene was downregulated, suggesting niclosamide may affect oxygen transport. Our results show that snails mount substantial responses to sublethal concentrations of niclosamide, at least some of which appear to be protective. The topic of how niclosamide's lethality at higher concentrations is determined requires further study. Given that niclosamide has also been used as an anthelmintic drug for decades and

  7. Effect of Niclosamide (Bayluscide WP 70 (R, Anacardium occidentale hexane extract and Euphorbia splendens latex on behavior of Biomphalaria glabrata (Say, 1818, under laboratory conditions

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    Pedro Jurberg

    1995-04-01

    Full Text Available The repellent effect of the molluscicides Niclosamide (Bayluscide WP 70 (R, Anacardium occidentale and the latex of Euphorbia splendens on Biomphalaria glabrata was observed through the investigation of the occurrence of escape behavior among molluscs that were exposed to dosages lower than the LD 50. The total number of individuals out of water among the surviving snails in the control group provided a "Natural Escape Index". The comparison between this total and the total number of surviving snails in each group exposed to the different dosages of the molluscicides after 24 hr provided the "Molluscicide Escape Index" and the detection of a "Repellency Range" to these snails. The escape indexes for Niclosamide, A. occidentale and E. splendens were 10, 6.22 and 6.44 respectively. Repellency occurred at the following concentration ranges: 0.01, 0.02 and 0.03 ppm Bayluscide, 0.1, 0.2 and 0.3 ppm A. occidentale and 0.05, 0.10, 0.15 and 0.20 ppm E. splendens. The Natural Escape Index obtained in the control group was zero.

  8. Biomphalaria alexandrina in Egypt: past, present and future.

    Science.gov (United States)

    Abou-El-Naga, Iman F

    2013-09-01

    The African species of Biomphalaria appeared as a result of the relatively recent west-to-east trans-Atlantic dispersal of the Biomphalaria glabrata-like taxon. In Egypt, Biomphalaria alexandrina is the intermediate host for Schistosoma mansoni. Biomphalaria alexandrina originated in the area between Alexandria and Rosetta and has historically been confined to the Nile Delta. Schistosoma mansoni reached Egypt via infected slaves and baboons from the Land of Punt through migrations that occurred as early as the Vth Dynasty. The suggestion of the presence of Schistosoma mansoni infection in Lower Egypt during Pharaonic times is discussed despite the fact that that there is no evidence of such infection in Egyptian mummies. It is only recently that Biomphalaria alexandrina colonized the Egyptian Nile from the Delta to Lake Nasser. This change was likely due to the construction of huge water projects, the development of new water resources essential for land reclamation projects and the movement of refugees from the Suez Canal zone to the Delta and vice versa. The situation with respect to Biomphalaria in Egypt has become complicated in recent years by the detection of Biomphalaria glabrata and a hybrid between both species; however, follow-up studies have demonstrated the disappearance of such species within Egypt. The National Schistosoma Control Program has made great strides with respect to the eradication of schistosoma; however, there has unfortunately been a reemergence of Schistosoma mansoni resistant to praziquantel. There are numerous factors that may influence the prevalence of snails in Egypt, including the construction of water projects, the increase in reclaimed areas, global climate change and pollution. Thus, continued field studies in addition to the cooperation of several scientists are needed to obtain an accurate representation of the status of this species. In addition, the determination of the genome sequence for Biomphalaria alexandrina and the

  9. Biomphalaria alexandrina in Egypt: Past, present and future

    Indian Academy of Sciences (India)

    Iman F Abou-El-Naga

    2013-09-01

    The African species of Biomphalaria appeared as a result of the relatively recent west-to-east trans-Atlantic dispersal of the Biomphalaria glabrata-like taxon. In Egypt, Biomphalaria alexandrina is the intermediate host for Schistosoma mansoni. Biomphalaria alexandrina originated in the area between Alexandria and Rosetta and has historically been confined to the Nile Delta. Schistosoma mansoni reached Egypt via infected slaves and baboons from the Land of Punt through migrations that occurred as early as the Vth Dynasty. The suggestion of the presence of Schistosoma mansoni infection in Lower Egypt during Pharaonic times is discussed despite the fact that that there is no evidence of such infection in Egyptian mummies. It is only recently that Biomphalaria alexandrina colonized the Egyptian Nile from the Delta to Lake Nasser. This change was likely due to the construction of huge water projects, the development of new water resources essential for land reclamation projects and the movement of refugees from the Suez Canal zone to the Delta and vice versa. The situation with respect to Biomphalaria in Egypt has become complicated in recent years by the detection of Biomphalaria glabrata and a hybrid between both species; however, follow-up studies have demonstrated the disappearance of such species within Egypt. The National Schistosoma Control Program has made great strides with respect to the eradication of schistosoma; however, there has unfortunately been a reemergence of Schistosoma mansoni resistant to praziquantel. There are numerous factors that may influence the prevalence of snails in Egypt, including the construction of water projects, the increase in reclaimed areas, global climate change and pollution. Thus, continued field studies in addition to the cooperation of several scientists are needed to obtain an accurate representation of the status of this species. In addition, the determination of the genome sequence for Biomphalaria alexandrina and the

  10. Paenibacillus, a novel pathogen of Biomphalaria glabrata, an intermediate host for schistosomiasis

    OpenAIRE

    Duval, David; Galinier, Richard; Mouahid, Gabriel; Toulza, Eve; Rognon, Anne; Arancibia, Nathalie; Allienne, Jean-François; Mitta, Guillaume; Théron, André; Gourbal, Benjamin

    2014-01-01

    Schistosomiasis is the second most widespread tropical parasitic disease after malaria. To achieve the objective of schistosomiasis eradication in a decade, various research strategies and treatment programs were recommended and supported by WHO. One of these applicable approaches is based on the control of snail vectors in endemic area. Previous field studies have shown that competitor or predator introduction could be effective but no systemic investigation has ever been conducted to identi...

  11. Histamine Immunoreactive Elements in the Central and Peripheral Nervous Systems of the Snail, Biomphalaria spp., Intermediate Host for Schistosoma mansoni.

    Directory of Open Access Journals (Sweden)

    Mohamed R Habib

    Full Text Available Histamine appears to be an important transmitter throughout the Animal Kingdom. Gastropods, in particular, have been used in numerous studies establishing potential roles for this biogenic amine in the nervous system and showing its involvement in the generation of diverse behaviours. And yet, the distribution of histamine has only previously been described in a small number of molluscan species. The present study examined the localization of histamine-like immunoreactivity in the central and peripheral nervous systems of pulmonate snails of the genus Biomphalaria. This investigation demonstrates immunoreactive cells throughout the buccal, cerebral, pedal, left parietal and visceral ganglia, indicative of diverse regulatory functions in Biomphalaria. Immunoreactivity was also present in statocyst hair cells, supporting a role for histamine in graviception. In the periphery, dense innervation by immunoreactive fibers was observed in the anterior foot, perioral zone, and other regions of the body wall. This study thus shows that histamine is an abundant transmitter in these snails and its distribution suggest involvement in numerous neural circuits. In addition to providing novel subjects for comparative studies of histaminegic neurons in gastropods, Biomphalaria is also the major intermediate host for the digenetic trematode parasite, which causes human schistosomiasis. The study therefore provides a foundation for understanding potential roles for histamine in interactions between the snail hosts and their trematode parasites.

  12. Aspectos físico-químicos e biológicos relacionados à ocorrência de Biomphalaria glabrata em focos litorâneos da esquistossomose em Pernambuco

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    Petronildo Bezerra da Silva

    2006-10-01

    Full Text Available This study analyzes the physico-chemical and biological parameters of freshwater aquatic environments in coastal areas of the State of Pernambuco, Brazil, where snail vector foci and cases of schistosomiasis have been recorded. The tests were carried out using standard methods and sediments were analyzed using the X-ray fluorescence technique. The micro-algae were analyzed using conventional microscopy. The most abundant chemical elements in the sediments were Fe, Ca, Si and Al and there were high concentrations of electrolytes in comparison with data published in the literature. The mean values for salinity (7.7 g/L and sulfate (489 mg/L were much higher than normal for freshwater environments. The micro-algae identified are those that inhabit environments with higher levels of salinity. The snail Biomphalaria glabrata seems, therefore, to be more tolerant to salty environments and this constitutes a risk of spread of schistosomiasis.

  13. Aspectos físico-químicos e biológicos relacionados à ocorrência de Biomphalaria glabrata em focos litorâneos da esquistossomose em Pernambuco

    Directory of Open Access Journals (Sweden)

    Silva Petronildo Bezerra da

    2006-01-01

    Full Text Available This study analyzes the physico-chemical and biological parameters of freshwater aquatic environments in coastal areas of the State of Pernambuco, Brazil, where snail vector foci and cases of schistosomiasis have been recorded. The tests were carried out using standard methods and sediments were analyzed using the X-ray fluorescence technique. The micro-algae were analyzed using conventional microscopy. The most abundant chemical elements in the sediments were Fe, Ca, Si and Al and there were high concentrations of electrolytes in comparison with data published in the literature. The mean values for salinity (7.7 g/L and sulfate (489 mg/L were much higher than normal for freshwater environments. The micro-algae identified are those that inhabit environments with higher levels of salinity. The snail Biomphalaria glabrata seems, therefore, to be more tolerant to salty environments and this constitutes a risk of spread of schistosomiasis.

  14. Strukturelle Charakterisierung hämolymphproteingebundener N-Glykane und immunhistochemische Lokalisierung antigener Strukturen von Biomphalaria glabrata, die mit Glykokonjugaten des Humanparasiten Schistosoma mansoni kreuzreagieren

    OpenAIRE

    Lehr, Tobias

    2007-01-01

    In der vorliegenden Arbeit wurden N-Glykane der Zwischenwirtsschnecke Biomphala¬ria glabrata, die mit Glykokonjugaten des Humanparasiten Schistosoma mansoni serolo¬gisch kreuzreagieren, strukturell charakterisiert. Dazu waren die N-Glykane aus Hämolymphproteinen nicht-infizierter Schnecken nach proteolytischem Verdau enzyma¬tisch freigesetzt, durch Immunaffinitätschromatographie unter Verwendung von immobilisierten Antikörpern gegen lösliche Eiantigene von S. mansoni (anti-SEA) angereichert, ...

  15. Compatibilidad entre nueve cepas de Biomphalaria glabrata de áreas endémicas y no endémicas y una cepa de Schistosoma mansoni venezolanas

    Directory of Open Access Journals (Sweden)

    Pino Luz A.

    1999-01-01

    Full Text Available Se infectaron experimentalmente 9 lotes de 32 caracoles B. glabrata (de 5 a 7mm de diámetro con miracidios de la cepa C5 de Schistosoma mansoni a razón de 5 miracidios por caracol, pertenecientes a las siguientes cepas: En el área endémica de transmisión de Esquistosomiasis mansoni a Sector Puerta Negra, Lago Valencia, b Cagua c Ingenio Bolívar (Estado Aragua d Mariara e Caserío El 25 f Güigüe (Estado Carabobo. Fuera del área endémica de transmisión g Anzoátegui (Estado Lara, h Chabasquén (Estado Portuguesa, i Sector La Elvira, Caripe (Estado Monagas. El período prepatente intramolusco, osciló entre 23 y 25 días, para las 9 cepas evaluadas. La duración total de la infección fue muy variable desde 20 días para la cepa Chabasquén, hasta 93 días para la de Güigüe.La producción total promedio de cercarias al tercer día de iniciada la emisión varió desde X = 74,4 para la cepa de Mariara, hasta X = 591,7 para la cepa de Chabasquén. Se evidenció la existencia de diferencias estadísticamente significativas (H = 97,4, P < 0,05 en la producción total de cercarias al tercer día de iniciada la emisión, detectándose diferencias estadísticamente significativas para casi todas las 36 combinaciones, excepto para las cuatro siguientes: Mariara/Ingenio Bolívar, Cagua/Caserío El 25, Lago de Valencia/Güigüe y Güigüe/Caripe.En lo que respecta al porcentaje de caracoles que presentaron cura espontánea, los valores mas elevados se obtuvieron en las cepas del Lago de Valencia (88,8%, Cagua (85,2%, Chabasquén (82,6%, Caripe (82,6% y Anzoátegui (80%. Mientras que el porcentaje mas bajo se obtuvo para la cepa de Güigüe (21,4%.

  16. Dispersão de Biomphalaria straminea, hospedeira intermediária do Schistosoma mansoni, através da distribuição de peixes The spreading of Biomphalaria straminea, intermediate host of Schistosoma mansoni through the distribution of fishes

    Directory of Open Access Journals (Sweden)

    Renato de R. Corrêa

    1970-12-01

    Full Text Available Foi focalizado, pela primeira vez o encontro de B. straminea no Estado de São Paulo. Esta espécie vem juntar-se aos planorbídeos já assinalados em nosso Estado. Foram descritos os criadouros, onde a B. straminea foi coletada, localizados em tanques de criação de peixes nas Estações de Piscicultura de Barra Bonita e Americana, Estado de São Paulo, e em um aquário particular na capital dêsse Estado. Fêz-se referência ao transporte de peixes oriundos de zonas do país onde ocorre aquela espécie, Amazonas e Ceará, como responsável pela introdução daquele molusco no Estado. Destacou-se êsse achado pelo perigo que representa a distribuição de peixes da maneira como vem sendo feita atualmente em nosso país, tendo sido julgado necessário o estabelecimento de quarentena para aquêles vindos de zonas infestadas por espécies hospedeiras intermediárias do S. mansoni. Foram relatadas as medidas de combate aos caramujos efetuadas imediatamente após aquela descoberta e os resultados obtidos. Conclui-se que a dispersão passiva da B. straminea pelo transporte de peixes, deve ampliar a distribuição geográfica dêsse planorbídeo, já assinalado na Venezuela, Guianas e no Brasil, sendo que neste último ocorre em tôdas as Unidades Federativas, exceto, no Rio Grande do Sul, Santa Catarina, Rio de Janeiro e Territórios.Up the present, the works of collecting planorbids done in 226 municipalities for the elaboration of the geographical distribution chart in the State of São Paulo (Brazil, showed the presence of two intermediate host species of Schistosoma mansoni: Biomphalaria tenagophila and Biompralaria glabrata. Although the technicians from the Psiculture Stations, have not found snails in the water inside the containers used for the transportation of fishes, the ecological conditions of B. straminea in the latest researches are such as to indicate that they have been introduced, in our State through fish transportation imported

  17. Influência do magnésio metálico e diferentes sais de magnésio em desovas de Biomphalaria glabrata (Say, 1818) Influence of metallic magnesium and various magnesium salts on egg-masses of Biomphalaria glabrata (Say, 1818)

    OpenAIRE

    Nelymar Martineli Mendes; Naftale Katz

    1983-01-01

    Soluções de magnésio metálico e diferentes sais de magnésio foram testadas em laboratório, a fim de comprovar a ação das mesmas sobre a oviposição de B. glabrata. Usaram-se, para cada solução, dez caramujos adultos originários da Pampulha, Belo Horizonte-MG (Brasil), criados em laboratório. No experimento I foram estudadas soluções em água desclorada de magnésio elementar (Mg), cloreto de magnésio (MgCl2.6H2O), carbonato de magnésio [(MgCO3)4.Mg(OH)2.nH2O], nitrato de magnésio [Mg(NO3)2. 6H2O...

  18. Influência do magnésio metálico e diferentes sais de magnésio em desovas de Biomphalaria glabrata (Say, 1818 Influence of metallic magnesium and various magnesium salts on egg-masses of Biomphalaria glabrata (Say, 1818

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    Nelymar Martineli Mendes

    1983-12-01

    Full Text Available Soluções de magnésio metálico e diferentes sais de magnésio foram testadas em laboratório, a fim de comprovar a ação das mesmas sobre a oviposição de B. glabrata. Usaram-se, para cada solução, dez caramujos adultos originários da Pampulha, Belo Horizonte-MG (Brasil, criados em laboratório. No experimento I foram estudadas soluções em água desclorada de magnésio elementar (Mg, cloreto de magnésio (MgCl2.6H2O, carbonato de magnésio [(MgCO34.Mg(OH2.nH2O], nitrato de magnésio [Mg(NO32. 6H2O] e sulfato de magnésio (MgSO4.7H2O, e no experimento II, Mg, Mg + latossolo, MgCO3, MgCO3 + latossolo, sempre nas concentrações de 500 e 1.000 ppm. Durante duas semanas os planorbídeos permaneceram em água para adaptação; em seguida, por quatro semanas em exposição com as soluções testadas e, posteriormente, em água por mais duas semanas para recuperação. A cada sete dias as desovas eram contadas, eliminadas e as soluções renovadas. Foi observado que as soluções de Mg e MgCO3, isoladamente ou associada ao latossolo, produziram uma diminuição significativa do número de desovas dos caramujos, mas não parada completa de oviposição, quando comparados os períodos de adaptação com os de exposição. As soluções de Mg e MgCO3 não devem ser consideradas como produtos promissores para o controle da população de B. glabrata, em virtude da diminuição das desovas só terem sido observadas quando foram utilizadas concentrações muito altas.Solutions of magnesium metallic and other salts of magnesium were tested in the laboratory to study the action on B. glabrata oviposition. For each solution, 10 adult snails from Pampulha, Belo Horizonte-MG (Brazil, reared in the laboratory, were used. In experiment I solutions, in dechlorinated water, of magnesium (Mg, magnesium chloride (MgCl2. 6H2O, magnesium carbonate [(MgCO34.Mg(OH2.nH2O], magnesium nitrate [Mg(NO32.6H2O] and magnesium sulfate (MgSO4.7H2O were tested; and in

  19. Biomphalaria straminea (Mollusca: Planorbidae) as an intermediate host of Drepanocephalus spp. (Trematoda: Echinostomatidae) in Brazil: a morphological and molecular study.

    Science.gov (United States)

    Pinto, Hudson A; Griffin, Matt J; Quiniou, Sylvie M; Ware, Cynthia; Melo, Alan L

    2016-01-01

    Species of trematodes belonging to the genus Drepanocephalus are intestinal parasites of piscivorous birds, primarily cormorants (Phalachrocorax spp.), and are widely reported in the Americas. During a 4-year malacological study conducted on an urban lake in Brazil, 27-collar-spined echinostome cercariae were found in 1665/15,459 (10.7 %) specimens of Biomphalaria straminea collected. The cercariae were identified as Drepanocephalus spp. by sequencing the 18S (SSU) rDNA, ITS1/5.8S rDNA/ITS2 (ITS), 28S (LSU) rDNA region, cytochrome oxidase subunit 1 (CO1), and nicotinamide adenine dinucleotide dehydrogenase subunit 1 (ND1) markers. In experimental life cycle studies, metacercariae developed in laboratory-reared guppies (Poecilia reticulata); however, attempts to infect birds and rodents were unsuccessful. Two closely related morphotypes of cercariae were characterized. One species, identified by molecular markers as a genetic variant of Drepanocephalus auritus (99.9 % similarity at SSU, ITS, LSU; 97.2 % at CO1; 95.8 % at ND1), differs slightly from an archived North American isolate of this species also sequenced as part of this study. A second species, putatively identified as Drepanocephalus sp., has smaller cercariae and demonstrates significant differences from D. auritus at the CO1 (11.0 %) and ND1 (13.6 %) markers. Aspects related to the morphological taxonomic identification of 27-collar-spined echinostome metacercariae are briefly discussed. This is the first report of the involvement of molluscs of the genus Biomphalaria in the transmission of Drepanocephalus and the first report of D. auritus in South America.

  20. Genetic variability and identification of the intermediate snail hosts of Schistosoma mansoni

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    Teofânia HDA Vidigal

    1998-01-01

    Full Text Available Studies based on shell or reproductive organ morphology and genetic considerations suggest extensive intraspecific variation in Biomphalaria snails. The high variability at the morphological and genetic levels, as well as the small size of some specimens and similarities between species complicate the correct identification of these snails. Here we review our work using methods based on polymerase chain reaction (PCR amplification for analysis of genetic variation and identification of Biomphalaria snails from Brazil, Argentina, Uruguay and Paraguay. Arbitrarily primed-PCR revealed that the genome of B. glabrata exihibits a remarkable degree of intraespecific polymorphism. Low stringency-PCR using primers for 18S rRNA permited the identification of B. glabrata, B. tenagophila and B. occidentalis. The study of individuals obtained from geographically distinct populations exhibits significant intraspecific DNA polymorphism, however specimens from the same species, exhibit some species specific LSPs. We also showed that PCR-restriction fragment of length polymorphism of the internal transcribed spacer region of Biomphalaria rDNA, using DdeI permits the differentiation of the three intermediate hosts of Schistosoma mansoni. The molecular biological techniques used in our studies are very useful for the generation of new knowledge concerning the systematics and population genetics of Biomphalaria snails.

  1. Susceptibility of Biomphalaria tenagophila and Biomphalaria straminea to Schistosoma mansoni infection detected by low stringency polymerase chain reaction

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    JANNOTTI-PASSOS Liana Konovaloff

    2000-01-01

    Full Text Available In order to determine Schistosoma mansoni infection rates in Biomphalaria tenagophila and B. straminea, low stringency polymerase chain reaction (LS-PCR technique was used as a complementary method to light exposure technique. LS-PCR has already been standardized in our laboratory to detect the trematode DNA in B. glabrata. Higher S. mansoni infection rates were detected using conventional method and LS-PCR. The parasite DNA profile was detected in both species after 7-day exposure to miracidia, using LS-PCR. This technique enables early detection of schistosomiasis transmission focuses, in endemic areas, before the beginning of cercariae shedding.

  2. Biomphalaria species distribution and its effect on human Schistosoma mansoni infection in an irrigated area used for rice cultivation in northeast Brazil

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    Delmany Moitinho Barboza

    2012-09-01

    Full Text Available The role of irrigated areas for the spread of schistosomiasis is of worldwide concern. The aim of the present study was to investigate the spatial distribution of the intermediate snail host Biomphalaria in an area highly endemic for schistosomiasis due to Schistosoma mansoni, evaluating the relationship between irrigation and types of natural water sources on one hand, and the influence of place and time of water exposure on the intensity of human infection on the other. A geographical information system (GIS was used to map the distribution of the intermediate snail hosts in Ilha das Flores, Sergipe, Brazil, combined with a clinical/epidemiological survey. We observed a direct correlation between the intensity of human infection with S. mansoni and irrigation projects. Malacological studies to identify snail species and infection rates showed that B. glabrata is the main species responsible for human schistosomiasis in the municipality, but that B. straminea also plays a role. Our results provide evidence for a competitive selection between the two snail species in rice fields with a predominance of B. glabrata in irrigation systems and B. straminea in natural water sources.

  3. The distribution of Biomphalaria spp. in different habitats in relation to physical, biological, water contact and cognitive factors in a rural area in Minas Gerais, Brazil

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    Kloos Helmut

    2001-01-01

    Full Text Available A total of 256 sites in 11 habitats were surveyed for Biomphalaria in Melquiades rural area (State of Minas Gerais in August and November 1999 and in March 2000. Of the 1,780 Biomphalaria collected, 1,721 (96.7% were B. glabrata and 59 (3.3% B. straminea. Snails were found in all habitats except in wells, with the largest mean numbers in tanks, seepage ponds and canals, and the smallest numbers in springs, rice fields and fishponds. People's knowledge of the occurrence of Biomphalaria at the collection sites and the presence of Biomphalaria ova were strongly correlated with the occurrence of snails, and distance between houses and collection sites, as well as water velocity were inversely correlated with Biomphalaria occurrence (p < 0.001. The strongest predictor o f Biomphalaria occurrence was the presence of tilapia fish in fishponds. Fourteen Biomphalaria (0.8% of all snails found at 6 sites were infected with Schistosoma mansoni. Suggestions are made for the utilization of local people's knowledge in snail surveys and further studies are recommended on the possible use of tilapia for biological control of Biomphalaria in fishponds, as well as modeling of S. mansoni transmission and reinfection.

  4. A Multiplex-PCR approach to identification of the Brazilian intermediate hosts of Schistosoma mansoni

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    Vidigal THDA

    2002-01-01

    Full Text Available Due to difficulties concerning morphological identification of planorbid snails of the genus Biomphalaria, and given a high variation of characters and in the organs with muscular tissue, we designed specific polymerase chain reaction (PCR primers for Brazilian snail hosts of Schistosoma mansoni from available sequences of internal transcribed spacer 2 (ITS2 of the ribosomal RNA gene. From the previous sequencing of the ITS2 region, one primer was designed to anchor in the 5.8S conserved region and three other species-specific primers in the 28S region, flanking the ITS2 region. These four primers were simultaneously used in the same reaction (Multiplex-PCR, under high stringency conditions. Amplification of the ITS2 region of Biomphalaria snails produced distinct profiles (between 280 and 350 bp for B. glabrata, B. tenagophila and B. straminea. The present study demonstrates that Multiplex-PCR of ITS2-DNAr showed to be a promising auxiliary tool for the morphological identification of Biomphalaria snails, the intermediate hosts of S. mansoni.

  5. Resistência de Biomphalaria peregrina de Santa Rita do Sapucaí, Minas Gerais, a infecção com três cepas de Schistosoma mansoni Resistance of Biomphalaria peregrina from Santa Rita do Sapucaí, State of Minas Gerais, Brazil, to infection with strain of Schistosoma mansoni

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    Cecília Pereira de Souza

    1988-12-01

    Full Text Available Descendentes do planorbídeo Biomphalaria peregrina, coletados em Santa Rita do Sapucaí, Minas Gerais, Brasil, foram expostos a miracídios de três cepas de Schistosoma mansoni: "LE" de Belo Horizonte, MG; "SJ" de São José dos Campos, SP e "AL" do Estado de Alagoas. Dentre 300 exemplares expostos, nenhum se infectou com as três cepas do trematódeo. Por outro lado, 300 exemplares de B. glabrata, dos grupos de controle, apresentaram taxas de infecção de 61,1 a 95,3% com as três cepas do trematódeo. As taxas de mortalidade de B. peregrina e de B. glabrata foram de 20,0 e de 28,0%, respectivamente.The descendants of the planorbid snail Biomphalaria peregrina, collected in the region of Santa rita do Sapucaí, Minas Gerais, Brazil, were exposed to miracidia of three strains of Schistosoma mansoni: "LE" strain from Belo Horizonte, State of Minas Gerais; "SJ", strain from São José dos Campos, State of São Paulo and "AL" strain from State of Alagoas. Of 300 snails exposed to miracidia of the three strains, none was infected. On the other hand, 300 Biomphalaria glabrata of the control groups showed infection rates of 61.1 to 95.3% with three strains. The mortality rates of B. peregrina and B. glabrata were 20% and 28%, respectively.

  6. Resistance of Biomphalaria occidentalis from Varzea das Flores dam, Minas Gerais, to Schistosoma mansoni infection detected by low stringency polymerase chain reaction

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    Cecilia Pereira de Souza

    2001-04-01

    Full Text Available Biomphalaria occidentalis Paraense, 1981 from Varzea das Flores dam, MG, Brazil, was exposed to infection with Schistosoma mansoni. Individual infection was performed with 140 B. occidentalis and 100 B. glabrata snails using LE and SJ strains. Two groups of B. occidentalis were killed after seven day-miracidia exposure to detect S. mansoni DNA, through the low stringency polymerase chain reaction (LS-PCR, and were negative. The infection rates were 69.2% (LE strain and 96.7% (SJ strain for B. glabrata and 0% for B. occidentalis. LS-PCR enabled early resistance diagnosis.

  7. Interaction between primary and secondary sporocysts of Schistosoma mansoni and the internal defence system of Biomphalaria resistant and susceptible to the parasite

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    Ana Carolina Alves de Mattos

    2011-06-01

    Full Text Available The outcome of the interaction between Biomphalaria and Schistosoma mansoni depends on the response of the host internal defence system (IDS and the escape mechanisms of the parasite. The aim of this study was to evaluate the responsiveness of the IDS (haemocytes and soluble haemolymph factors of resistant and susceptible Biomphalaria tenagophila lineages and Biomphalaria glabrata lineages in the presence of in vitro-transformed primary sporocysts and secondary sporocysts obtained from infected B. glabrata. To do this, we assayed the cellular adhesion index (CAI, analysed viability/mortality, used fluorescent markers to evaluate the tegumental damage and transplanted secondary sporocysts. B. tenagophila Taim was more effective against primary and secondary sporocystes than the susceptible lineage and B. glabrata. Compared with secondary sporocysts exposed to B. tenagophila, primary sporocysts showed a higher CAI, a greater percentage of dead sporocysts and were labelled by lectin from Glycine max and Alexa-Fluor 488 fluorescent probes at a higher rate than the secondary sporocysts. However, the two B. tenagophila lineages showed no cercarial shedding after inoculation with secondary sporocysts. Our hypothesis that secondary sporocysts can escape the B. tenagophila IDS cannot be confirmed by the transplantation experiments. These data suggest that there are additional mechanisms involved in the lower susceptibilty of B. tenagophila to S. mansoni infection.

  8. Compatibility of Ugandan Schistosoma mansoni isolates with Biomphalaria snail species from Lake Albert and Lake Victoria

    DEFF Research Database (Denmark)

    Adriko, Moses; Standley, Claire J.; Tinkitina, Benjamin;

    2013-01-01

    In order to investigate the capacity of being intermediate host for Schistosoma mansoni, the Ugandan F1 generation of Biomphalaria snail species that were laboratory-bred from parent populations originally collected from either Lake Victoria or Lake Albert was challenged with sympatric and non......-sympatric S. mansoni isolates. After a prepatent period of 20 days, a daily 10-hourly snail shedding for cercariae was done to determine the infection rate, cercarial production per hour and survival period of infected snails. The study suggests that when parasite strains from a different geographical origin...... is used for infection, survival of infected snails increase, leading to an increased transmission potential. Although earlier literature had indicated that the Lake Victoria Biomphalaria sudanica is refractory to S. mansoni, we showed that all Ugandan Biomphalaria spp., including B. sudanica from all...

  9. Esquistossomose: nova ocorrência de Biomphalaria straminea em Belo Horizonte, Minas Gerais Schistosomiasis: new occurrence of Biomphalaria straminea in Belo Horizonte, Minas Gerais

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    Cecília Pereira de Souza

    1996-12-01

    Full Text Available Em Belo Horizonte, Minas Gerais, Brasil, a Biomphalaria straminea é encontrada na região da Pampulha. Recentemente, o molusco foi encontrado em valas da antiga Barragem de Santa Lúcia, foco extinto de esquistossomose transmitida por B. glabrata. Os moluscos foram coletados e examinados para verificar se estavam naturalmente infectados com Schistosoma mansoni. Os exemplares negativos foram usados para criação ou infecção com a cepa LE de S. mansoni, mantida no laboratório, e outra cepa VGS, obtida de ovos de fezes de escolar de Belo Horizonte. Dentre 1.890 moluscos capturados em 1994 e 1995, nenhum estava infectado com S. mansoni. Dentre 87 exemplares coletados no criadouro e expostos à cepa LE, nove (10,3% eliminaram cercárias; dentre 83 moluscos da F1, dez (12,0% eliminaram cercárias e dentre 88 exemplares coletados e expostos à cepa VGS, dez (11,3% eliminaram cercárias. Em Belo Horizonte, a esquistossomose é transmitida por B. glabrata e B. tenagophila. Entretanto, atualmente existe o risco de aparecimento de novo foco, no qual a B. straminea poderá vir a ser a transmissora, se medidas profiláticas adequadas não forem tomadas pelas autoridades responsáveis pela construção de um parque e lago no local.In Belo Horizonte, Minas Gerais, Brazil, the snail Biomphalaria straminea was found in the Pampulha region. Recently the snail was found in ditches in the old Santa Lúcia Reservoir, a now-extinct focus of schistosomiasis transmission by B. glabrata. The snails were collected and examined to verify whether they were naturally infected with Schistosoma mansoni. Negative specimens were used for breeding or infection with the LE strain of S. mansoni from the laboratory and another strain obtained from eggs found in the feces of a schoolchild (VGS from Belo Horizonte. Among the 1890 snails collected from 1994 to 1995, none were infected with S. mansoni. Among 87 snails collected and exposed to the LE strain, 9 (10.3% shed cercariae

  10. Estudo da potencialidade de populações de Biomphalaria straminea do Estado de Minas Gerais, como hospedeiras do Schistosoma mansoni Potentiality of the Biomphalaria straminea populations of the State of Minas Gerais, as hosts of Schistosoma mansoni

    Directory of Open Access Journals (Sweden)

    Cecília Pereira de Souza

    1983-09-01

    Full Text Available Caramujos de Biomphalaria straminea, descendentes de exemplares coletados em nove municípios do Estado de Minas Gerais, foram infectados experimentalmente com três cepas de Schistosoma mansoni: "LE", procedente de Belo Horizonte (MG; "SJ", procedente de São José dos Campos (SP e "AL" procedente do Nordeste (AL. As taxas de infeção variaram de 0,0 a 24,0% com a cepa "LE"; de 0,0 a 16% com a cepa "SJ" e de 2,0 a 9,0% com a cepa "AL". Os índices de infecção experimental obtidos foram semelhantes aos registrados por outros autores, para B. straminea dessa região. Comparou-se o número de cercárias de cepa "LE", eliminadas por oito exemplares de B. straminea de Baldim e oito Biomphalaria glabrata do controle, após 30 minutos de exposição à luz. O número de cercárias eliminadas por B. straminea foi de 4.550, aproximadamente cinco vezes menor que o de B. glabrata, 22.679. Discute-se a potencialidade desses moluscos como hospedeiros do S. mansoni nessa região.The decendents of Biomphalaria straminea snails collected in nine regions from the State of Minas Gerais were experimentally infected with three strains of Schistosoma mansoni: "LE", from Belo Horizonte, Minas Gerais; "SJ", from São José dos Campos, State of São Paulo and "AL", from State of Alagoas. The infection rates obtained were of 0 to 24% (LE strain, 0 to 16% (SJ strain and 2 to 9% (AL strain. These infection rates were similar to those obtained by other authors for B. straminea from this region. Comparation were made between the numbers of cercariae (LE strain shed by eight specimens of B. straminea from Baldim and eight B. glabrata of the control group, after 30 minutes of exposure to light. B. straminea shed 4,550 cercariae, about five times less than B. glabrata (22,679. The authors discuss the potentiality of theses molluscs as hosts of S. mansoni in this region.

  11. Genetic Variation between Biomphalaria alexandrina Snails Susceptible and Resistant to Schistosoma mansoni Infection

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    Suzanne M. F. El-Nassery

    2013-01-01

    Full Text Available Much effort has been made to control schistosomiasis infection in Egypt. However, enduring effects from such strategies have not yet been achieved. In this study, we sought to determine the genetic variability related to the interaction between Biomphalaria alexandrina snails and Schistosoma mansoni. Using RAPD-PCR with eight (10 mers random primers, we were able to determine the polymorphic markers that differed between snails susceptible and resistant to Schistosoma mansoni infection using five primers out of the eight. Our results suggest that the RAPD-PCR technique is an efficient means by which to compare genomes and to detect genetic variations between schistosomiasis intermediate hosts. The RAPD technique with the above-noted primers can identify genomic markers that are specifically related to the Biomphalaria alexandrina/Schistosoma mansoni relationship in the absence of specific nucleotide sequence information. This approach could be used in epidemiologic surveys to investigate genetic diversity among Biomphalaria alexandrina snails. The ability to determine resistant markers in Biomphalaria alexandrina snails could potentially lead to further studies that use refractory snails as agents to control the spread of schistosomiasis.

  12. Characterization of Biomphalaria orbignyi, Biomphalaria peregrina and Biomphalaria oligoza by polymerase chain reaction and restriction enzyme digestion of the internal transcribed spacer region of the RNA ribosomal gene

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    Spatz Linus

    2000-01-01

    Full Text Available The correct identification of Biomphalaria oligoza, B. orbignyi and B. peregrina species is difficult due to the morphological similarities among them. B. peregrina is widely distributed in South America and is considered a potential intermediate host of Schistosoma mansoni. We have reported the use of the polymerase chain reaction and restriction fragment length polymorphism analysis of the internal transcribed spacer region of the ribosomal DNA for the molecular identification of these snails. The snails were obtained from different localities of Argentina, Brazil and Uruguay. The restriction patterns obtained with MvaI enzyme presented the best profile to identify the three species. The profiles obtained with all enzymes were used to estimate genetic similarities among B. oligoza, B. peregrina and B. orbignyi. This is also the first report of B. orbignyi in Uruguay.

  13. Morphological characterization of the hemocytes of the pulmonate snail Biomphalaria tenagophila

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    Margherita Anna Barracco

    1993-03-01

    Full Text Available The blood cells of the pulmonate snail Biomphalaria tenagophila, an important transmiter of the trematode Schistosoma mansoni in Brazil, were examined by ligth and transmission electron microscopy (TEM. Two hemocyte types were identified: hyalinocytes and granulocytes. Hyalinocytes are small young (immature, poorly spreading cells, which have a high nucleocytoplasmic ratio and are especially rich in free ribosomes. They do not appear to contain lysosome-like bodies and represent less than 10% of the circulating hemocytes. Granulocytes are larger hemocytes which readily spread on glass surface and which strongly react to the Gomori substrate, indicating the enzyme acid phosphatase usually found in lysosomes. Ultra-structurally, they contain a well-developed rough endoplasmic reticulum, dictyosomes and some some lysosome-like dense bodies. Granulocytes do not exhibit a characteristic granular aspect and the few granules observed in the cytoplasm should correspond to a lysosome system. They were named granulocytes instead of amoebocytes to use the same terminology adopted for Biomphalaria glabrata in order to make easier comparative studies. This is a preface study for more specific investigations on the functional activities of the blood cells of B. tenagophila and their interactions with the trematode parasite.

  14. Morphological and polymerase chain reaction-restriction fragment lenght polymorphism characterization of Biomphalaria kuhniana and Biomphalaria amazonica from Colombia

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    Luz E Velásquez

    2002-10-01

    Full Text Available In Colombia, five Biomphalaria planorbid species are known: B. kuhniana, B. straminea, B. peregrina, B. canonica and B. oligoza(var. B. philippiana. Among them, B. straminea is intermediate host of Schistosoma mansoni and B. peregrina has been found to be experimentally susceptible to this parasite. B. straminea is commonly confused with B. kuhniana and they have been clustered together with B. intermedia in the complex named B. straminea. The difficulties involved in the specific identification, based on morphological data, have motivated the use of new techniques as auxiliary tools in cases of inconclusive morphological identification of such planorbid. In the present study, five Biomphalaria populations from the Colombian Amazon region and from Interandian Valleys were morphologically identified and characterized by polymerase chain reaction-restriction fragment lenght polymorphism directed at the internal transcribed spacer region of the rRNA gene, followed by digestion of the generated fragment with restriction enzymes (DdeI, AluI, RsaI, MvaI and HaeIII. Known profiles of the Brazilian species B. straminea, B. peregrina, B. kuhniana, B. intermedia and B. amazonica, besides B. kuhniana from Colombia, were used for comparison. The five populations under study were morphologically and molecularly identified as B. kuhniana and B. amazonica.

  15. Large-scale determinants of intestinal schistosomiasis and intermediate host snail distribution across Africa

    DEFF Research Database (Denmark)

    Stensgaard, Anna-Sofie; Utzinger, Jürg; Vounatsou, Penelope;

    2013-01-01

    to climate change. Here, we combine a growing degree day model for Schistosoma mansoni with species distribution models for the intermediate host snail (Biomphalaria spp.) to investigate large-scale environmental determinants of the distribution of the African S. mansoni-Biomphalaria system and potential...

  16. The nuclear receptors of Biomphalaria glabrata and Lottia gigantea: Implications for developing new model organisms

    OpenAIRE

    Satwant Kaur; Susan Jobling; Jones, Catherine S.; Noble, Leslie R; Routledge, Edwin J.; Lockyer, Anne E.

    2015-01-01

    © 2015 Kaur et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited Nuclear receptors (NRs) are transcription regulators involved in an array of diverse physiological functions including key roles in endocrine and metabolic function. The aim of this study was to identify nuclear receptors in the fully seque...

  17. Intermediate hosts of schistosoma mansoni in Brazil

    OpenAIRE

    Omar dos Santos Carvalho

    1992-01-01

    The Brazilian planorbidical chart is slowly but progressively been increased by new data. Distribution of vector species of Schistosoma mansoni, according to Paraense, 1986, may be thus resumed: Biomphalaria glabrata - delimited by paralells 13 and 21-S and meridians 39 and 45-W, area of greater dominance (Southerst Bahia, oriental half of Minas Gerais and Espírito Santo). It is observed along the coast line of the state of Sergipe, Alagoas, Pernambuco, Paraíba and Rio Grande do Norte. Starti...

  18. Irrigation canals in Melo creek basin (Rio Espera and Capela Nova municipalities, Minas Gerais, Brazil): habitats to Biomphalaria (Gastropoda: Planorbidae) and potential spread of schistosomiasis.

    Science.gov (United States)

    Leite, M G P; Pimenta, E C; Fujaco, M A G; Eskinazi-Sant'Anna, E M

    2016-04-19

    This study analyzed the presence of Biomphalaria in Melo creek basin, Minas Gerais state, and its relationship to irrigation canals. Seventeen of these canals were used to determine a limnological, morphological and hydrological characterization during an annual seasonal cycle. Biomphalaria samples were sent to René Rachou Research Center/FIOCRUZ for identification and parasitological examination. Six canals were identified as breeding areas for mollusks and in one of them it was registered the coexistence of B. tenagophila (first report to this basin) and B. glabrata species. Results indicated that the low flow rate and speed of water flow were the main characteristics that contributed to this specific growth of the mollusks in the area. These hydraulic characteristics were created due to anthropogenic action through the canalization of lotic areas in Melo creek, which allowed ideal ecological conditions to Biomphalaria outbreak. The results emphasize the need of adequate handling and constant monitoring of the hydrographic basin, subject to inadequate phytosanitary conditions, aiming to prevent the occurrence and propagation of schistosomiasis. PMID:27097093

  19. Activity of Polyphenolic Compounds against Candida glabrata

    Directory of Open Access Journals (Sweden)

    Ricardo Salazar-Aranda

    2015-09-01

    Full Text Available Opportunistic mycoses increase the morbidity and mortality of immuno-compromised patients. Five Candida species have been shown to be responsible for 97% of worldwide cases of invasive candidiasis. Resistance of C. glabrata and C. krusei to azoles has been reported, and new, improved antifungal agents are needed. The current study was designed to evaluatethe activity of various polyphenolic compounds against Candida species. Antifungal activity was evaluated following the M27-A3 protocol of the Clinical and Laboratory Standards Institute, and antioxidant activity was determined using the DPPH assay. Myricetin and baicalein inhibited the growth of all species tested. This effect was strongest against C. glabrata, for which the minimum inhibitory concentration (MIC value was lower than that of fluconazole. The MIC values against C. glabrata for myricitrin, luteolin, quercetin, 3-hydroxyflavone, and fisetin were similar to that of fluconazole. The antioxidant activity of all compounds was confirmed, and polyphenolic compounds with antioxidant activity had the greatest activity against C. glabrata. The structure and position of their hydroxyl groups appear to influence their activity against C. glabrata.

  20. Ciclo biológico de Paraibatrema inesperata n.g., n.sp. (Trematoda, Paramphistomidae, a partir de metacercárias desenvolvidas em Biomphalaria tenagophila (D'Orbigny, 1835 (Mollusca, Planorbidae

    Directory of Open Access Journals (Sweden)

    Marlene Tiduko Ueta

    1981-03-01

    Full Text Available Em exemplares de B. tenagophila, capturados em ambiente natural, foram encontradas paranfistomocercárias de precoce encistamento. Procedeu-se à infecção, per os, de animais de biotério; em camundongos e ratos, verificou-se o desenvolviemnto de trematóide paranfistomídeo desconhecido e que, por suas características, não se enquadra nos g~eneros conhecidos de Paramphistomidae de mamíferos. Para o parasito em apreço é proposta a denominação Paraibatema inesperata n.g, n.sp.. A partir de miracídios, oriundos de ovos eliminados pelos roedores em experiência, procurou-se infectar B. tenagophila e B. glabrata, criadas no moluscário. Verificou-se ser ativa a penetração dos miracídios no tecido do molusco, sendo freqüente a formação de tumorações nas antenas. A evolução experimental no hospedeiro intermediário apresenta-se lenta; ao fim de 40 dias de pós-infecção, não se observou a formação de esporocistos, rédias e cercárias.The new genus and new species of paramphistomid trematode, Paraibatrema inesperata n.g, n.sp., are proposed. The parasite was originally found as a quickly encysting paramphistome cercaria from specimens of the planorbid snail Biomphalaria tenagophila caught in natural habitats. Experimental infection resulted from intubation of metacercariae into the stomach of white mice and rats, which passed eggs in the feces 20 days later. Specimens of B. tenagophila and B. glabrata have been exposed to miracidia from eggs passed by mice. Penetration of the molluscan tegument was observed, but it seems that the larval development of the parasite is slow, inasmuch as no rediae and cercariae have been obtained as yet.

  1. Molluscicidal effect of suspension concentrate of niclosamide against Biomphalaria glabrata, an intermediate host of Schistosoma mansoni%氯硝柳胺悬浮剂杀灭曼氏血吸虫中间宿主光滑双脐螺效果观察

    Institute of Scientific and Technical Information of China (English)

    戴建荣; 汪伟; 李洪军; 陶永辉; Gerald C Coles; 梁幼生

    2009-01-01

    目的 观察氯硝柳胺悬浮剂(SCN)对光滑双脐螺的杀灭效果.方法 用SCN、50%氯硝柳胺乙醇胺盐可湿性粉剂(WPN)和氯硝柳胺原药分别配制成药物有效浓度为1.000、0.500、0.250、0.125 mg/L和0.063 mg/L的溶液,在实验室浸泡光滑双脐螺成螺,计算LC50.采用上述3种剂型的氯硝柳胺分别配制成药物有效浓度为0.500、0.250、0.125、0.063mg/L和0.032 mg/L的溶液,浸泡螺卵,计算LC50.结果 将成螺浸泡在SCN、WPN和氯硝柳胺溶液中,24 h LC50分别为0.218、0.218 mg/L和0.203 mg/L;48 h LC50分别为0.189、0.203 mg/L和0.189 me,/L;72 h LC50分别为0.165、0.218 mg/L和0.177 mg/L.将螺卵浸泡在SCN、WPN和氯硝柳胺溶液中,24 h LC50分别为0.153、0.173 mg/L和0.171 mg/L;48 hLC50分别为0.085、0.096 mg/L和0.155 mg/L;72 h LC50分别为0.077、0.097 mg/L和0.087 mg/L.结论 SCN对光滑双脐螺成螺和螺卵均具有与WPN和原药相同的杀灭效果.

  2. Breeding of Biomphalaria tenagophila in mass scale

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    Florence Mara Rosa

    2013-02-01

    Full Text Available An efficient method for breeding Biomphalaria tenagophila (Taim lineage/RS was developed over a 5-year-period (2005-2010. Special facilities were provided which consisted of four cement tanks (9.4 x 0.6 x 0.22 m, with their bottom covered with a layer of sterilized red earth and calcium carbonate. Standard measures were adopted, as follows: each tank should contain an average of 3000 specimens, and would be provided with a daily ration of 35,000 mg complemented with lettuce. A green-house effect heating system was developed which constituted of movable dark canvas covers, which allowed the temperature to be controlled between 20 - 24 ºC. This system was essential, especially during the coldest months of the year. Approximately 27,000 specimens with a diameter of 12 mm or more were produced during a 14-month-period. The mortality rates of the newly-hatched and adult snails were 77% and 37%, respectively. The follow-up of the development system related to 310 specimens of B. tenagophila demonstrated that 70-day-old snails reached an average of 17.0 ± 0.9 mm diameter. The mortality rates and the development performance of B. tenagophila snails can be considered as highly satisfactory, when compared with other results in literature related to works carried out with different species of the genus Biomphalaria, under controlled laboratory conditions.

  3. Hybridism between Biomphalaria cousini and Biomphalaria amazonica and its susceptibility to Schistosoma mansoni

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    Tatiana Maria Teodoro

    2011-11-01

    Full Text Available Molecular techniques can aid in the classification of Biomphalaria species because morphological differentiation between these species is difficult. Previous studies using phylogeny, morphological and molecular taxonomy showed that some populations studied were Biomphalaria cousini instead of Biomphalaria amazonica. Three different molecular profiles were observed that enabled the separation of B. amazonica from B. cousini. The third profile showed an association between the two and suggested the possibility of hybrids between them. Therefore, the aim of this work was to investigate the hybridism between B. cousini and B. amazonica and to verify if the hybrids are susceptible to Schistosoma mansoni. Crosses using the albinism factor as a genetic marker were performed, with pigmented B. cousini and albino B. amazonica snails identified by polymerase chain reaction-restriction fragment length polymorphism. This procedure was conducted using B. cousini and B. amazonica of the type locality accordingly to Paraense, 1966. In addition, susceptibility studies were performed using snails obtained from the crosses (hybrids and three S. mansoni strains (LE, SJ, AL. The crosses between B. amazonica and B. cousini confirmed the occurrence of hybrids. Moreover, hybrids can be considered potential hosts of S. mansoni because they are susceptible to LE, SJ and AL strains (4.4%, 5.6% and 2.2%, respectively. These results indicate that there is a risk of introducing schistosomiasis mansoni into new areas.

  4. Activity of Polyphenolic Compounds against Candida glabrata

    OpenAIRE

    Ricardo Salazar-Aranda; Graciela Granados-Guzmán; Jonathan Pérez-Meseguer; González, Gloria M.; Noemí Waksman de Torres

    2015-01-01

    Opportunistic mycoses increase the morbidity and mortality of immuno-compromised patients. Five Candida species have been shown to be responsible for 97% of worldwide cases of invasive candidiasis. Resistance of C. glabrata and C. krusei to azoles has been reported, and new, improved antifungal agents are needed. The current study was designed to evaluatethe activity of various polyphenolic compounds against Candida species. Antifungal activity was evaluated following the M27-A3 protocol of t...

  5. Effects of Varying Concentrations of the Crude Aqueous and Ethanolic Extracts of Dalbergia Sissoo Plant Parts on Biomphalaria Pfeifferi Egg Masses

    OpenAIRE

    Adenusi, Adedotun A; Odaibo, Alexander B

    2009-01-01

    This study evaluated, using replicated laboratory bioassays, the toxicities of the crude aqueous and ethanolic extracts of Dalbergia sissoo Roxb. 1832 (family Leguminosae) fruits, leaves, roots and stem bark against egg masses of Biomphalaria pfeifferi (Krauss, 1848), the snail intermediate host of Schistosoma mansoni (Sambon, 1907) in Nigeria. Viable 0–24 hr-old embryonated egg masses were separately exposed to five different concentrations (7.81–2000 mg/l) of extracts for 24 hrs, washed in ...

  6. Proteogenomic analysis of Candida glabrata using high resolution mass spectrometry.

    NARCIS (Netherlands)

    Prasad, T.S.; Harsha, H.C.; Keerthikumar, S.; Sekhar, N.R.; Selvan, L.D.N.; Kumar, P.; Pinto, S.M.; Muthusamy, B.; Subbannayya, Y.; Renuse, S.; Chaerkady, R.; Mathur, P.P.; Ravikumar, R.; Pandey, A.

    2012-01-01

    Candida glabrata is a common opportunistic human pathogen leading to significant mortality in immunosuppressed and immunodeficient individuals. We carried out proteomic analysis of C. glabrata using high resolution Fourier transform mass spectrometry with MS resolution of 60,000 and MS/MS resolution

  7. Measurement of Selected Enzymatic Activities in Solanum nigrum-Treated Biomphalaria arabica Snails

    Science.gov (United States)

    Al-Daihan, Sooad

    In the present study, glucose, acid and alkaline phosphatases (ACP and ALP), α-amylase and lipase were measured for the first time in tissue homogenates of Biomphalaria arabica snails, molluscan intermediate host for Schistosoma mansoni in Saudi Arabia. Also, the effect of sublethal concentrations (LC25) of dry powdered Solanum nigrum leaf was tested as plant molluscicide against this snail species. The tested enzymes were altered in molluscicide-treated snails compared to control. While ALP and amylase were slightly affected, ACP and lipase were significantly altered. Glucose as an important energy source for a successful schistosome-snail relationship was significantly reduced in molluscicide-treated snails. In conclusion, sublethal concentration of the molluscicide showed potent effect in disturbing snail biochemistry which may render them physiologically unsuitable for the developing of schistosome parasite. This could be considered as a promising strategy to control the disease.

  8. Molecular characterisation of intermediate snail hosts and the search for resistance genes

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    David Rollinson

    1998-01-01

    Full Text Available The relationship between schistosomes and their intermediate hosts is an extremely intricate one with strains and species of the parasite depending on particular species of snail, which in turn may vary in their susceptibility to the parasites. In order to gain a better understanding of the epidemiology of the disease we have been investigating the use of molecular markers for snail identification and for studying host-parasite relationships. In this paper we will draw on examples concerning schistosomiasis in West and East Africa to illustrate how a molecular analysis can be used as part of a "total evidence" approach to characterisation of Bulinus species and provide insights into parasite transmission. Particular emphasis is given to ribosomal RNA genes (rRNA, random amplified polymorphic DNA (RAPDs and the mitochondrial gene cytochrome oxidase I (COI. Snails resistant to infection occur naturally and there is a genetic basis for this resistance. In Biomphalaria glabrata resistance to Schistosoma mansoni is known to be a polygenic trait and we have initiated a preliminary search for snail genomic regions linked to, or involved in, resistance by using a RAPD based approach in conjunction with progeny pooling methods. We are currently characterising a variety of STSs (sequence tagged sites associated with resistance. These can be used for local linkage and interval mapping to define genomic regions associated with the resistance trait. The development of such markers into simple dot-blot or specific PCR-based assays may have a direct and practical application for the identification of resistant snails in natural populations.

  9. Molecular approach for detecting early prepatent Schistosoma mansoni infection in Biomphalaria alexandrina snail host.

    Science.gov (United States)

    Farghaly, Adel; Saleh, Ayman A; Mahdy, Soad; Abd El-Khalik, Dalia; Abd El-Aal, Naglaa F; Abdel-Rahman, Sara A; Salama, Marwa A

    2016-09-01

    The present study aimed to evaluate a polymerase chain reaction (PCR) assay used for detection of Schistosoma mansoni infection in Biomphalaria alexandrina snails in early prepatent period and to compare between it and the ordinary detection methods (shedding and crushing). Biomphalaria alexandrina snails are best known for their role as intermediate hosts of S. mansoni. DNA was extracted from infected snails in addition to non-infected "negative control" (to optimized the efficiency of PCR reaction) and subjected to PCR using primers specific to a partial sequence of S. mansoni fructose-1,6-bus phosphate aldolase (SMALDO). SMALDO gene was detected in the infected laboratory snails with 70, 85, and 100 % positivity at the 1st, 3rd, and 7th day of infection, respectively. In contrast, the ordinary method was not sensitive enough in detection of early prepatent infection even after 7 days of infection which showed only 25 % positivity. By comparing the sensitivity of the three methods, it was found that the average sensitivity of shedding method compared to PCR was 23.8 % and the average sensitivity of crushing method compared to PCR was 46.4 % while the sensitivity of PCR was 100 %. We conclude that PCR is superior to the conventional methods and can detect positive cases that were negative when examined by shedding or crushing methods. This can help in detection of the areas and times of high transmission which in turn will be very beneficial in planning of the exact timing of the proper control strategy.

  10. Molecular approach for detecting early prepatent Schistosoma mansoni infection in Biomphalaria alexandrina snail host.

    Science.gov (United States)

    Farghaly, Adel; Saleh, Ayman A; Mahdy, Soad; Abd El-Khalik, Dalia; Abd El-Aal, Naglaa F; Abdel-Rahman, Sara A; Salama, Marwa A

    2016-09-01

    The present study aimed to evaluate a polymerase chain reaction (PCR) assay used for detection of Schistosoma mansoni infection in Biomphalaria alexandrina snails in early prepatent period and to compare between it and the ordinary detection methods (shedding and crushing). Biomphalaria alexandrina snails are best known for their role as intermediate hosts of S. mansoni. DNA was extracted from infected snails in addition to non-infected "negative control" (to optimized the efficiency of PCR reaction) and subjected to PCR using primers specific to a partial sequence of S. mansoni fructose-1,6-bus phosphate aldolase (SMALDO). SMALDO gene was detected in the infected laboratory snails with 70, 85, and 100 % positivity at the 1st, 3rd, and 7th day of infection, respectively. In contrast, the ordinary method was not sensitive enough in detection of early prepatent infection even after 7 days of infection which showed only 25 % positivity. By comparing the sensitivity of the three methods, it was found that the average sensitivity of shedding method compared to PCR was 23.8 % and the average sensitivity of crushing method compared to PCR was 46.4 % while the sensitivity of PCR was 100 %. We conclude that PCR is superior to the conventional methods and can detect positive cases that were negative when examined by shedding or crushing methods. This can help in detection of the areas and times of high transmission which in turn will be very beneficial in planning of the exact timing of the proper control strategy. PMID:27605788

  11. Differentiation of the sibling species Biomphalaria occidentalis and Biomphalaria tenagophila by the electrophoretic patterns of their hemoglobin

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    James B. Bailey

    1986-09-01

    Full Text Available A simple and rapid method for differentialing the sibling species Biomphalaria tenagophila and Biomphalaria occidentalis by agarose gel electrophoresis (AGE is described. Snail hemolymph is used as the test sample and the red colaration of the hemoglobin fraction permits visualization of the migration patterns without resorting to specific stains. Moreover, hemolymph samples may be obtained without killing the snail, thus permitting its use for other studies for breeding.É descrito um método simples e rápido para distinguir as espécies crípticas Biomphalaria tenagophila e B. occidentalis por eletroforese em gel de agarose. A prova é feita com hemolinfa do molusco, permitindo a cor vermelha da fração hemoglobina visualizar os padrões de migração sem necessidade de recorrer a colorações específicas. Além disso, as amostras de hemolinfa podem ser obtidas sem sacrificar o molusco, que poderá ser usado para outros estudos ou para criação.

  12. Diversity and antifungal susceptibility of Norwegian Candida glabrata clinical isolates

    Science.gov (United States)

    Andersen, Kari-Mette; Kristoffersen, Anne Karin; Ingebretsen, André; Vikholt, Katharina Johnsen; Örtengren, Ulf Thore; Olsen, Ingar; Enersen, Morten; Gaustad, Peter

    2016-01-01

    Background Increasing numbers of immunocompromised patients have resulted in greater incidence of invasive fungal infections with high mortality. Candida albicans infections dominate, but during the last decade, Candida glabrata has become the second highest cause of candidemia in the United States and Northern Europe. Reliable and early diagnosis, together with appropriate choice of antifungal treatment, is needed to combat these challenging infections. Objectives To confirm the identity of 183 Candida glabrata isolates from different human body sites using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) and VITEK®2, and to analyze isolate protein profiles and antifungal susceptibility. The minimum inhibitory concentration (MIC) of seven antifungal drugs was determined for the isolates to elucidate susceptibility. Design A total of 183 C. glabrata isolates obtained between 2002 and 2012 from Norwegian health-care units were analyzed. For species verification and differentiation, biochemical characterization (VITEK®2) and mass spectrometry (MALDI–TOF) were used. MIC determination for seven antifungal drugs was undertaken using E-tests®. Results Using VITEK®2, 92.9% of isolates were identified as C. glabrata, while all isolates (100%) were identified as C. glabrata using MALDI-TOF. Variation in protein spectra occurred for all identified C. glabrata isolates. The majority of isolates had low MICs to amphotericin B (≤1 mg/L for 99.5%) and anidulafungin (≤0.06 mg/L for 98.9%). For fluconazole, 18% of isolates had MICs >32 mg/L and 82% had MICs in the range ≥0.016 mg/L to ≤32 mg/L. Conclusions Protein profiles and antifungal susceptibility characteristics of the C. glabrata isolates were diverse. Clustering of protein profiles indicated that many azole resistant isolates were closely related. In most cases, isolates had highest susceptibility to amphotericin B and anidulafungin. The results confirmed previous observations of high

  13. Biomphalaria straminea no Peru e sua suscetibilidade a cepas brasileiras de Schistosoma mansoni

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    C.A. Cuba Cuba

    1977-12-01

    Full Text Available Em Maio de 1973, um dos autores (C.A.C. coletou na localidade de Imacita, Província de Bagua, Departamento de Amazonas, vários espécimes de Biomphalaria straminea (Dunker, 1848, uma espécie que, até então, não havia sido assinalada no Peru. Descendentes destes indivíduos foram submetidos a provas de suscetibilidade às cepas BH e SJ de Schistosoma mansoni que, em condições naturais, evoluem em B. glabrata de Belo Horizonte e B. tenagophila de São José dos Campos, respectivamente. Oitenta espécimens foram expostos à cepa BH dos quais em 13 ou 16,2% a infecção evoluiu caracteristicamente até a formação de esporocistos secundários sem haver, contudo, eliminação de cercárias, mesmo no indivíduo que apresentou uma sobrevivência de 88 dias após a exposição. Não se verificou cura espontânea neste lote. Entre as 40 B. straminea expostas à cepa SJ 9 ou 22,5% infectaram-se, sendo que apenas duas eliminaram poucas cercárias aos 57 e 77 dias após a exposição, por dois dias consecutivos, tendo uma morrido e uma se curado espontaneamente. A cura espontânea do parasitismo foi notado em mais dois indivíduos, nos quais a infecção foi observada através da concha. Cortes histológicos seriados de 9 caramujos, expostos individualmente a 50 miracídios da cepa BH e fixados entre 6 e 120 horas após a exposição, mostraram esporocistos em desenvolvimento e esporocistos invadidos por amebócitos, sem formação de granulomas por parte do hospedeiro, fato assinalado em caramujos suscetíveis. A população estudada comportou-se experimentalmente de modo semelhante a outras populações de B. straminea testadas em laboratório, isto é, com baixa suscetibilidade, embora tal comportamento não afaste a possibilidade dela vir a manter o ciclo do parasita em sua área de distribuição.In May 1973 one of the Authors (C.A.C. collected specimens of Biomphalaria straminea (Dunker 1848 at imacita, Bagua Province, Amazonas, Pem. This

  14. Candida glabrata Binding to Candida albicans Hyphae Enables Its Development in Oropharyngeal Candidiasis.

    Science.gov (United States)

    Tati, Swetha; Davidow, Peter; McCall, Andrew; Hwang-Wong, Elizabeth; Rojas, Isolde G; Cormack, Brendan; Edgerton, Mira

    2016-03-01

    Pathogenic mechanisms of Candida glabrata in oral candidiasis, especially because of its inability to form hyphae, are understudied. Since both Candida albicans and C. glabrata are frequently co-isolated in oropharyngeal candidiasis (OPC), we examined their co-adhesion in vitro and observed adhesion of C. glabrata only to C. albicans hyphae microscopically. Mice were infected sublingually with C. albicans or C. glabrata individually, or with both species concurrently, to study their ability to cause OPC. Infection with C. glabrata alone resulted in negligible infection of tongues; however, colonization by C. glabrata was increased by co-infection or a pre-established infection with C. albicans. Furthermore, C. glabrata required C. albicans for colonization of tongues, since decreasing C. albicans burden with fluconazole also reduced C. glabrata. C. albicans hyphal wall adhesins Als1 and Als3 were important for in vitro adhesion of C. glabrata and to establish OPC. C. glabrata cell wall protein coding genes EPA8, EPA19, AWP2, AWP7, and CAGL0F00181 were implicated in mediating adhesion to C. albicans hyphae and remarkably, their expression was induced by incubation with germinated C. albicans. Thus, we found a near essential requirement for the presence of C. albicans for both initial colonization and establishment of OPC infection by C. glabrata.

  15. Intermediate hosts of schistosoma mansoni in Brazil

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    Omar dos Santos Carvalho

    1992-01-01

    Full Text Available The Brazilian planorbidical chart is slowly but progressively been increased by new data. Distribution of vector species of Schistosoma mansoni, according to Paraense, 1986, may be thus resumed: Biomphalaria glabrata - delimited by paralells 13 and 21-S and meridians 39 and 45-W, area of greater dominance (Southerst Bahia, oriental half of Minas Gerais and Espírito Santo. It is observed along the coast line of the state of Sergipe, Alagoas, Pernambuco, Paraíba and Rio Grande do Norte. Starting from there, it is found towards the southwest, in the direction to the Sao Francisco River and South-Center of Minas Gerais. Isolated population may be observed in other states. Its presence is probably, associated to the transmission of schistosomiasis in all areas where it occurs. B. tenagophila - extends it self through a wide strip of coast-line the South of Bahia (17-45"S, 39-15'W, RS(33-41'S, 53-27'W. In Sao Paulo and Rio Grande do Sul states it is found further inland. It is important in schistosomiasis transmission in the Paraíba valley (SP. Isolated populations are observed in the Federal District and Minas Gerais state. B. straminea - better adapter species to climatic variation, having a more dense ditribution in the northeast (41-Wand 110-S, south of Bahia and northeast of Minas Gerais (150 and 180-S, 400 and 440-W It is less susceptible than B. glabrata, being however the most important responsible for the transmission of S. mansoni in the northeast, chiefly in the northeastern dry area, where it is almost the only transmissive species.

  16. Identification of Biomphalaria havanensis and Biomphalaria obstructa populations from Cuba using polymerase chain reaction and restriction fragment length polymorphism of the ribosomal RNA intergenic spacer

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    Teofânia HDA Vidigal

    2001-07-01

    Full Text Available In Cuba, several Biomphalaria species have been reported such as B. orbignyi, B. schrammi, B. helophila, B. havanensis and B. peregrina; only the latter three are considered as potential hosts of Schistosoma mansoni. The specific identification of Biomphalaria species is based on anatomical and morphological characters of genital organs and shells. The correct identification of these snails is complicated by the high variation in these characters, similarity among species and in some cases by the small size of the snails. In this paper, we reported the classical morphological identification, the use of PCR and RFLP analysis of the internal transcribed spacer region of the ribosomal RNA genes for molecular identification of seven snail populations from different localities in Cuba. Using morphological and molecular analysis, we showed that among the studied Cuban Biomphalaria populations only B. havanensis and B. obstructa species were found.

  17. Nueva especie de Planorbidae (Gastropoda: Basommatophora en la Patagonia chilena: Biomphalaria cristiani sp. nov. First record of Planorbidae (Mollusca: Basommatophora in Chilean Patagonia: Biomphalaria cristiani sp. nov.

    Directory of Open Access Journals (Sweden)

    Carmen Fuentealba

    2012-11-01

    Full Text Available En Chile la familia Planorbidae está representada por el género Biomphalaria Preston, 1910, compuesta por siete especies distribuidas desde Isluga hasta el río Puelo. De estas especies, solo B.peregrina, ampliamente distribuida en el neotrópico, y Biomphalaria aymara de Isluga, han sido reconocidas sobre la base de la morfología del sistema reproductor y la rádula, caracteres que fueron utilizados en el presente estudio para diferenciar a Biomphalaria cristiani como nueva especie del grupo y primer registro de la familia en la Patagonia chilena, ampliando su actual rango de distribución. Los caracteres que permiten la diagnosis de B. cristiani son el saco vaginal vestigial truncado, ausencia del desarrollo de los músculos suspensores del pene, vaina del pene corta en relación al prepucio, oviducto largo en relación al espermioducto y vaso deferente más delgado y largo que la vaina del pene, de tamano similar al prepucio. La localidad tipo de Biomphalaria cristiani sp. nov. es Laguna Cisnes (47°7'10.02"S, 72°27'40.65"W, región de Aysén.The family Planorbidae in Chile is represented by the genus Biomphalaria Preston, 1910, consisting of seven species distributed from Isluga to Puelo River. Of these species, only Biomphalaria peregrina widely distributed in the neotropical and Biomphalaria aymara from Isluga are recognized based on the morphology of the reproductive system and radula, characters that were used in the following study to differentiate Biomphalaria cristiani as a new species of this group and first record of the family in Chilean Patagonia, extending its current distribution range. The characters for the diagnosis of B. cristiani are: truncated vestigial vaginal pouch, lack of development of the penis retractor muscles, penis sheath shorter than the prepuce, oviduct longer than the spermiduct and vas deferens thinner and longer than the penis sheath, similar size to the prepuce. The type locality of B. cristiani nov. sp

  18. Candida glabrata : a review of its features and resistance

    OpenAIRE

    Rodrigues, Célia F.; Silva, Sónia Carina; Henriques, Mariana

    2014-01-01

    Candida species belong to the normal microbiota of the oral cavity and gastrointestinal and vaginal tracts, and are responsible for several clinical manifestations, from mucocutaneous overgrowth to bloodstream infections. Once believed to be non-pathogenic, Candida glabrata was rapidly blamable for many human diseases. Year after year, these pathological circumstances are more recurrent and problematic to treat, especially when patients reveal any level of immunosuppression. These difficultie...

  19. Role of Dectin-2 for Host Defense against Systemic Infection with Candida glabrata

    NARCIS (Netherlands)

    Ifrim, D.C.; Bain, J.M.; Reid, D.M.; Oosting, M.; Verschueren, I.; Gow, N.A.; Krieken, J.H.J.M. van; Brown, G.D.; Kullberg, B.J.; Joosten, L.A.B.; Meer, J.W.M. van der; Koentgen, F.; Erwig, L.P.; Quintin, J.; Netea, M.G.

    2014-01-01

    Although Candida glabrata is an important pathogenic Candida species, relatively little is known about its innate immune recognition. Here, we explore the potential role of Dectin-2 for host defense against C. glabrata. Dectin-2-deficient (Dectin-2(-/-)) mice were found to be more susceptible to C.

  20. The Drosophila Toll pathway controls but does not clear Candida glabrata infections.

    Science.gov (United States)

    Quintin, Jessica; Asmar, Joelle; Matskevich, Alexey A; Lafarge, Marie-Céline; Ferrandon, Dominique

    2013-03-15

    The pathogenicity of Candida glabrata to patients remains poorly understood for lack of convenient animal models to screen large numbers of mutants for altered virulence. In this study, we explore the minihost model Drosophila melanogaster from the dual perspective of host and pathogen. As in vertebrates, wild-type flies contain C. glabrata systemic infections yet are unable to kill the injected yeasts. As for other fungal infections in Drosophila, the Toll pathway restrains C. glabrata proliferation. Persistent C. glabrata yeasts in wild-type flies do not appear to be able to take shelter in hemocytes from the action of the Toll pathway, the effectors of which remain to be identified. Toll pathway mutant flies succumb to injected C. glabrata. In this immunosuppressed background, cellular defenses provide a residual level of protection. Although both the Gram-negative binding protein 3 pattern recognition receptor and the Persephone protease-dependent detection pathway are required for Toll pathway activation by C. glabrata, only GNBP3, and not psh mutants, are susceptible to the infection. Both Candida albicans and C. glabrata are restrained by the Toll pathway, yet the comparative study of phenoloxidase activation reveals a differential activity of the Toll pathway against these two fungal pathogens. Finally, we establish that the high-osmolarity glycerol pathway and yapsins are required for virulence of C. glabrata in this model. Unexpectedly, yapsins do not appear to be required to counteract the cellular immune response but are needed for the colonization of the wild-type host.

  1. Modification of Biomphalaria straminea eggs enclose induced by gamma radiation

    International Nuclear Information System (INIS)

    A vector of Schistosomiasis, the mollusk Biomphalaria straminea, can procreate by means of sexual - when in colonies - or by hermaphrodite fecundation, if isolated. In order to study its reproductive behavior under gamma radiation, 540 snails kept in colony and 540 maintained isolated in individual aquariums, were irradiated with doses, 0, 2,5, 5,0, 7,5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 80, 160, 320 and 640 Gy of gamma-rays from a 60 Co. source, and were observed during 30 days. Daily, the off spring were collected from the aquariums, its eggs counted and maintained in Petri's plate, in water. After eight days, the eggs were counted again and the difference with the first count representing the hatched eggs. As a result, the eggs from the snails kept in colony showed a greater number of encloses than those from the isolated snails, ranging from 2,5 to 40 Gy. Beyond this dose the difference between the two observed groups were statistically non significant, leading to suppose a greater resistance of the sexually fecundation to the influence of gamma-rays. (author). 16 refs, 1 fig, 1 tab

  2. Compatibility of Schistosoma mansoni Cameroon and Biomphalaria pfeifferi Senegal.

    Science.gov (United States)

    Southgate, V R; Tchuenté, L A; Théron, A; Jourdane, J; Ly, A; Moncrieff, C B; Gryseels, B

    2000-11-01

    The vectorial capacity of Biomphalaria pfeifferi from Ndiangue, Senegal, was investigated with an allopatric isolate of Schistosoma mansoni from Nkolbisson, Cameroon. The snail infection rate after exposure to a single miracidium per snail (MD1) was 56. 3 %, and 91.6%, for snails exposed to 5 miracidia per snail (MD5). The minimum pre-patent period was 21 days. The mean total cercarial production for the MDI group was 18,511 cercariae per snail, and 9757 cercariae for the MD5 group. The maximum production of cercariae for 1 day was 4892 observed in a snail from the MDI group at day 43 post-infection. The mean longevity of snails was higher in group MD1 (88 days p.i.) than in group MD5 (65 days p.i.). The chronobiological emergence pattern revealed a circadian rhythm with one shedding peak at mid-day. Comparisons are made with the vectorial capacity of the sympatric combination of B. pfeifferi Senegal/S. mansoni Senegal.

  3. Altered Gene Expression in the Schistosome-Transmitting Snail Biomphalaria glabrata following Exposure to Niclosamide, the Active Ingredient in the Widely Used Molluscicide Bayluscide

    OpenAIRE

    Zhang, Si-Ming; Buddenborg, Sarah K; Adema, Coen M.; Sullivan, John T.; Loker, Eric S

    2015-01-01

    In view of the call by the World Health Organization (WHO) for elimination of schistosomiasis as a public health problem by 2025, use of molluscicides in snail control to supplement chemotherapy–based control efforts is likely to increase in the coming years. The mechanisms of action of niclosamide, the active ingredient in the most widely used molluscicides, remain largely unknown. A better understanding of its toxicology at the molecular level will both improve our knowledge of snail biolog...

  4. Susceptibility of Argentinean Biomphalaria tenagophila and Biomphalaria straminea to infection by Schistosoma mansoni and the possibility of geographic expansion of mansoni schistosomiasis

    Directory of Open Access Journals (Sweden)

    Luciana Franceschi Simoes

    2013-10-01

    Full Text Available Introduction Human migration and the presence of natural vectors (mollusks of Schistosoma mansoni are the primary causes of the expansion of mansoni schistosomiasis into southern areas of South America. Water conditions are favorable for the expansion of this disease because of the extensive hydrographic network, which includes the basins of the Paraná and Uruguay rivers and favors mollusk reproduction. These rivers also aid agriculture and tourism in the area. Despite these favorable conditions, natural infection by S. mansoni has not yet been reported in Argentina, Uruguay, or Paraguay. Methods Two species of planorbid from Argentina, Biomphalaria straminea and B. tenagophila, were exposed to the miracidia of five Brazilian strains of S. mansoni. Results Biomphalaria tenagophila (Atalaya, Buenos Aires province was infected with the SJS strain (infection rate 3.3%, confirming the experimental susceptibility of this Argentinian species. Biomphalaria straminea (Rio Santa Lucía, Corrientes province was susceptible to two Brazilian strains: SJS (infection rate 6.7% and Sergipe (infection rate 6.7%. Conclusions These results demonstrate that species from Argentina have the potential to be natural hosts of S. mansoni and that the appearance of foci of mansoni schistosomiasis in Argentina is possible.

  5. Primeira ocorrência de Biomphalaria straminea no Sul Goiano, Brasil First occurrence of Biomphalaria straminea in the South Goiano, Brazil

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    Carlos Henrique Marchiori

    1999-12-01

    Full Text Available Relata-se a primeira ocorrência do Biomphalaria straminea no Sul do Estado de Goiás, em ambiente natural. Trinta exemplares de Biomphalaria straminea foram coletados em janeiro de 1998, em Cachoeira Dourada de Goiás. Verificou-se que a falta de saneamento e de educação sanitária da população e a presença do caramujo são condições fundamentais para o estabelecimento de um foco de transmissão.The objective of this note is to report the occurrence of the Biomphalaria straminea in the county of Cachoeira Dourada in the south of Goiás, and with that enhance the knowledge about its geographical distribution in the state. More than identify the species, the collection of thirty samples helped study and verify the presence of cercariae, especially because they were found in a setting which offers proper conditions to the development of a focal transmission site of schistosomiasis.

  6. Biomphalaria alexandrina as a bioindicator of metal toxicity.

    Science.gov (United States)

    Habib, Mohamed R; Mohamed, Azza H; Osman, Gamalat Y; Mossalem, Hanan S; Sharaf El-Din, Ahmed T; Croll, Roger P

    2016-08-01

    Heavy metals are common environmental pollutants to the aquatic ecosystems. Several aquatic species have been used as bioindicators and biomonitoring subjects for heavy metals pollution. In the present study, the effects of cadmium (Cd) and manganese (Mn) on the survival, attachment, locomotion, and feeding behaviours of the gastropod snail Biomphalaria alexandrina were determined. The short-term (96 h) LC50 for Cd and Mn were found to be 0.219 and 154.2 mg/l, respectively. Long-term exposures (16-20 days) to ascending concentrations of Cd (0.01-1 mg/l) and Mn (50-500 mg/l) also caused gradual decreases in the survival rate of B. alexandrina in a dose-dependent manner. Attachment, locomotion and feeding behaviours of snails exposed to lethal and sublethal concentrations of Cd and Mn at acute (96 h) and chronic exposure (24 days) intervals, respectively, were also recorded. Compared to controls, a significant decrease (p ≤ 0.05) was recorded in the different behaviours of exposed snails. These changes in behaviour would potentially impact the snail's ability to survive in the wild. Although Cd caused a more severe decline in snail survivorship than Mn, the behavioural effects of Mn were much more severe than Cd when the metals were roughly matched for lethality. In sum, the present study demonstrates B. alexandrina to be a sensitive bioindicator and model organism to assess heavy metals risk factors for severe toxicity in freshwater ecosystems. PMID:27209558

  7. Alien Planorbid (Mollusca, Gastropoda Pulmonata) from South West Africa erroneously recorded as Biomphalaria Pfeifferi

    NARCIS (Netherlands)

    Bruggen, van A.C.

    1974-01-01

    In 1970 I published a record of the freshwater snail Biomphalaria pfeifferi (Krauss, 1848) (fam. Planorbidae) for South West Africa: "Sandamap Farm, Spitzkoppe" (Van Bruggen, 1970: 45, figs. 1-13). Dr. D. S. Brown of the Medical Research Council (London) kindly drew my attention to the fact that jud

  8. Candida glabrata Esophagitis: Are We Seeing the Emergence of a New Azole-Resistant Pathogen?

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    Aze Wilson

    2014-01-01

    Full Text Available Background. Candida glabrata (C. glabrata has become a recognized pathogen in fungal esophagitis. A proportion of these isolates are azole-resistant which may have treatment implications. Variability in the prevalence of this organism exists in the limited data available. Objective. To determine the incidence of C. glabrata esophagitis in a North American hospital setting and to highlight factors that may predispose patients to this condition. Methods. Patient charts were collected from January 1, 2009 to July 30, 2011. Any charts of patients identified as having esophagitis with a positive fungal culture were reviewed for the species of Candida and the presence of factors that would predispose them to esophageal candidiasis. Results. The prevalence of Candida esophagitis based on culture was 2.2% (37 subjects. C. glabrata was the 2nd most prevalent pathogen identified (24.3% or 9 subjects. Of the C. glabrata cohort, all patients had at least one factor predisposing them to candidiasis. Conclusion. C. glabrata esophagitis makes up a large portion of the candidal esophagitis seen in hospital. C. glabrata infections were associated with at least one risk factor for candidal infection. Given its resistance to azole-based therapy, this may have treatment implications for how candidal esophagitis is approached by the clinician.

  9. Iron-depletion promotes mitophagy to maintain mitochondrial integrity in pathogenic yeast Candida glabrata

    Science.gov (United States)

    Nagi, Minoru; Tanabe, Koichi; Nakayama, Hironobu; Ueno, Keigo; Yamagoe, Satoshi; Umeyama, Takashi; Ohno, Hideaki; Miyazaki, Yoshitsugu

    2016-01-01

    ABSTRACT Candida glabrata, a haploid budding yeast, is the cause of severe systemic infections in immune-compromised hosts. The amount of free iron supplied to C. glabrata cells during systemic infections is severely limited by iron-chelating proteins such as transferrin. Thus, the iron-deficiency response in C. glabrata cells is thought to play important roles in their survival inside the host's body. In this study, we found that mitophagy was induced under iron-depleted conditions, and that the disruption of a gene homologous to ATG32, which is responsible for mitophagy in Saccharomyces cerevisiae, blocked mitophagy in C. glabrata. The mitophagic activity in C. glabrata cells was not detected on short-period exposure to nitrogen-starved conditions, which is a mitophagy-inducing condition used in S. cerevisiae. The mitophagy-deficient atg32Δ mutant of C. glabrata also exhibited decreased longevity under iron-deficient conditions. The mitochondrial membrane potential in Cgatg32Δ cells was significantly lower than that in wild-type cells under iron-depleted conditions. In a mouse model of disseminated infection, the Cgatg32Δ strain resulted in significantly decreased kidney and spleen fungal burdens compared with the wild-type strain. These results indicate that mitophagy in C. glabrata occurs in an iron-poor host tissue environment, and it may contribute to the longevity of cells, mitochondrial quality control, and pathogenesis. PMID:27347716

  10. Neutrophil activation by Candida glabrata but not Candida albicans promotes fungal uptake by monocytes.

    Science.gov (United States)

    Duggan, Seána; Essig, Fabian; Hünniger, Kerstin; Mokhtari, Zeinab; Bauer, Laura; Lehnert, Teresa; Brandes, Susanne; Häder, Antje; Jacobsen, Ilse D; Martin, Ronny; Figge, Marc Thilo; Kurzai, Oliver

    2015-09-01

    Candida albicans and Candida glabrata account for the majority of candidiasis cases worldwide. Although both species are in the same genus, they differ in key virulence attributes. Within this work, live cell imaging was used to examine the dynamics of neutrophil activation after confrontation with either C. albicans or C. glabrata. Analyses revealed higher phagocytosis rates of C. albicans than C. glabrata that resulted in stronger PMN (polymorphonuclear cells) activation by C. albicans. Furthermore, we observed differences in the secretion of chemokines, indicating chemotactic differences in PMN signalling towards recruitment of further immune cells upon confrontation with Candida spp. Supernatants from co-incubations of neutrophils with C. glabrata primarily attracted monocytes and increased the phagocytosis of C. glabrata by monocytes. In contrast, PMN activation by C. albicans resulted in recruitment of more neutrophils. Two complex infection models confirmed distinct targeting of immune cell populations by the two Candida spp.: In a human whole blood infection model, C. glabrata was more effectively taken up by monocytes than C. albicans and histopathological analyses of murine model infections confirmed primarily monocytic infiltrates in C. glabrata kidney infection in contrast to PMN-dominated infiltrates in C. albicans infection. Taken together, our data demonstrate that the human opportunistic fungi C. albicans and C. glabrata are differentially recognized by neutrophils and one outcome of this differential recognition is the preferential uptake of C. glabrata by monocytes.

  11. Biomphalaria obstructa (Morelet, 1849: a study of topotypic specimens (Mollusca: pulmonata: planorbidae

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    W. Lobato Paraense

    1990-12-01

    Full Text Available A description of Biomphalaria obstructa (Morelet, 1849, based on specimens collected at its type locality - isla del carmen, state of Campeche, Mexico - is presented. The Shell is small, 13 mm in diameter, 3.5 mm in width and with 5.75 whorls in the largest specimen, thin, moderately lustrous and translucent, horn-colored. Whorls increasing regularly (neither slowly nor rapidly in diameter, rounded on the periphery side, bluntly angular on the left. Suture well-marked, deeper on the left. Right side widely concave, with first whorl deeply situated and partly hidden by the next. Left side shallower than right one, largely flattened, with first whorl plaintly visible. Aperture roundly heart-shaped, usually in the same plane as the body whorl but somewhat deflected to the left (less frequently to the right in some specimens. Peristome sharp, seldom blunt; a distinct callus on the parietal wall. A number of young shells develop one set (seldom more of apertural lamellae which tend to be resorbed as the shell grows. Absence of renal ridge. Ovotestis with about 70 mostly unbrached diverticula. Seminal vesicle beset with well-developed knoblike to fingerlike diverticula. Vaginal pouch more or less developed. Spermatheca club-shaped when empty, egg-shaped when full, and with intermediate forms between those extremes. Spermathecal body usually somewhat longer than the duct. Prostate with 7 to 20 (mean 12.06 ± 2.51 usually short diverticula which give off plumpish branches spreading out in a fan shape and overlapping to some extent their immediate neighbors. Foremost prostatic diverticulum nearly always partially or completely inserted between the spermathecal body and the uterine wall. Penial sheath consistently narrower and shorter than the prepuce. Muscular coat of the penis consisting of an inner longitudinal and an outer circular layers. Ratios between organ lengths: caudal to cephalic parts of female duct = 0.55 to 1.37 (mean 0.85 +- 0.17; cephalic

  12. Partial Decay of Thiamine Signal Transduction Pathway Alters Growth Properties of Candida glabrata

    Science.gov (United States)

    Shaik, Noor F.; Neal, Erin M.; Leone, Sarah G.; Cali, Brian J.; Peel, Michael T.; Grannas, Amanda M.; Wykoff, Dennis D.

    2016-01-01

    The phosphorylated form of thiamine (Vitamin B1), thiamine pyrophosphate (TPP) is essential for the metabolism of amino acids and carbohydrates in all organisms. Plants and microorganisms, such as yeast, synthesize thiamine de novo whereas animals do not. The thiamine signal transduction (THI) pathway in Saccharomyces cerevisiae is well characterized. The ~10 genes required for thiamine biosynthesis and uptake are transcriptionally upregulated during thiamine starvation by THI2, THI3, and PDC2. Candida glabrata, a human commensal and opportunistic pathogen, is closely related to S. cerevisiae but is missing half of the biosynthetic pathway, which limits its ability to make thiamine. We investigated the changes to the THI pathway in C. glabrata, confirming orthologous functions. We found that C. glabrata is unable to synthesize the pyrimidine subunit of thiamine as well as the thiamine precursor vitamin B6. In addition, THI2 (the gene encoding a transcription factor) is not present in C. glabrata, indicating a difference in the transcriptional regulation of the pathway. Although the pathway is upregulated by thiamine starvation in both species, C. glabrata appears to upregulate genes involved in thiamine uptake to a greater extent than S. cerevisiae. However, the altered regulation of the THI pathway does not alter the concentration of thiamine and its vitamers in the two species as measured by HPLC. Finally, we demonstrate potential consequences to having a partial decay of the THI biosynthetic and regulatory pathway. When the two species are co-cultured, the presence of thiamine allows C. glabrata to rapidly outcompete S. cerevisiae, while absence of thiamine allows S. cerevisiae to outcompete C. glabrata. This simplification of the THI pathway in C. glabrata suggests its environment provides thiamine and/or its precursors to cells, whereas S. cerevisiae is not as reliant on environmental sources of thiamine. PMID:27015653

  13. Partial Decay of Thiamine Signal Transduction Pathway Alters Growth Properties of Candida glabrata.

    Directory of Open Access Journals (Sweden)

    Christine L Iosue

    Full Text Available The phosphorylated form of thiamine (Vitamin B1, thiamine pyrophosphate (TPP is essential for the metabolism of amino acids and carbohydrates in all organisms. Plants and microorganisms, such as yeast, synthesize thiamine de novo whereas animals do not. The thiamine signal transduction (THI pathway in Saccharomyces cerevisiae is well characterized. The ~10 genes required for thiamine biosynthesis and uptake are transcriptionally upregulated during thiamine starvation by THI2, THI3, and PDC2. Candida glabrata, a human commensal and opportunistic pathogen, is closely related to S. cerevisiae but is missing half of the biosynthetic pathway, which limits its ability to make thiamine. We investigated the changes to the THI pathway in C. glabrata, confirming orthologous functions. We found that C. glabrata is unable to synthesize the pyrimidine subunit of thiamine as well as the thiamine precursor vitamin B6. In addition, THI2 (the gene encoding a transcription factor is not present in C. glabrata, indicating a difference in the transcriptional regulation of the pathway. Although the pathway is upregulated by thiamine starvation in both species, C. glabrata appears to upregulate genes involved in thiamine uptake to a greater extent than S. cerevisiae. However, the altered regulation of the THI pathway does not alter the concentration of thiamine and its vitamers in the two species as measured by HPLC. Finally, we demonstrate potential consequences to having a partial decay of the THI biosynthetic and regulatory pathway. When the two species are co-cultured, the presence of thiamine allows C. glabrata to rapidly outcompete S. cerevisiae, while absence of thiamine allows S. cerevisiae to outcompete C. glabrata. This simplification of the THI pathway in C. glabrata suggests its environment provides thiamine and/or its precursors to cells, whereas S. cerevisiae is not as reliant on environmental sources of thiamine.

  14. Dissection of Ire1 functions reveals stress response mechanisms uniquely evolved in Candida glabrata.

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    Taiga Miyazaki

    2013-01-01

    Full Text Available Proper protein folding in the endoplasmic reticulum (ER is vital in all eukaryotes. When misfolded proteins accumulate in the ER lumen, the transmembrane kinase/endoribonuclease Ire1 initiates splicing of HAC1 mRNA to generate the bZIP transcription factor Hac1, which subsequently activates its target genes to increase the protein-folding capacity of the ER. This cellular machinery, called the unfolded protein response (UPR, is believed to be an evolutionarily conserved mechanism in eukaryotes. In this study, we comprehensively characterized mutant phenotypes of IRE1 and other related genes in the human fungal pathogen Candida glabrata. Unexpectedly, Ire1 was required for the ER stress response independently of Hac1 in this fungus. C. glabrata Ire1 did not cleave mRNAs encoding Hac1 and other bZIP transcription factors identified in the C. glabrata genome. Microarray analysis revealed that the transcriptional response to ER stress is not mediated by Ire1, but instead is dependent largely on calcineurin signaling and partially on the Slt2 MAPK pathway. The loss of Ire1 alone did not confer increased antifungal susceptibility in C. glabrata contrary to UPR-defective mutants in other fungi. Taken together, our results suggest that the canonical Ire1-Hac1 UPR is not conserved in C. glabrata. It is known in metazoans that active Ire1 nonspecifically cleaves and degrades a subset of ER-localized mRNAs to reduce the ER load. Intriguingly, this cellular response could occur in an Ire1 nuclease-dependent fashion in C. glabrata. We also uncovered the attenuated virulence of the C. glabrata Δire1 mutant in a mouse model of disseminated candidiasis. This study has unveiled the unique evolution of ER stress response mechanisms in C. glabrata.

  15. Partial Decay of Thiamine Signal Transduction Pathway Alters Growth Properties of Candida glabrata.

    Science.gov (United States)

    Iosue, Christine L; Attanasio, Nicholas; Shaik, Noor F; Neal, Erin M; Leone, Sarah G; Cali, Brian J; Peel, Michael T; Grannas, Amanda M; Wykoff, Dennis D

    2016-01-01

    The phosphorylated form of thiamine (Vitamin B1), thiamine pyrophosphate (TPP) is essential for the metabolism of amino acids and carbohydrates in all organisms. Plants and microorganisms, such as yeast, synthesize thiamine de novo whereas animals do not. The thiamine signal transduction (THI) pathway in Saccharomyces cerevisiae is well characterized. The ~10 genes required for thiamine biosynthesis and uptake are transcriptionally upregulated during thiamine starvation by THI2, THI3, and PDC2. Candida glabrata, a human commensal and opportunistic pathogen, is closely related to S. cerevisiae but is missing half of the biosynthetic pathway, which limits its ability to make thiamine. We investigated the changes to the THI pathway in C. glabrata, confirming orthologous functions. We found that C. glabrata is unable to synthesize the pyrimidine subunit of thiamine as well as the thiamine precursor vitamin B6. In addition, THI2 (the gene encoding a transcription factor) is not present in C. glabrata, indicating a difference in the transcriptional regulation of the pathway. Although the pathway is upregulated by thiamine starvation in both species, C. glabrata appears to upregulate genes involved in thiamine uptake to a greater extent than S. cerevisiae. However, the altered regulation of the THI pathway does not alter the concentration of thiamine and its vitamers in the two species as measured by HPLC. Finally, we demonstrate potential consequences to having a partial decay of the THI biosynthetic and regulatory pathway. When the two species are co-cultured, the presence of thiamine allows C. glabrata to rapidly outcompete S. cerevisiae, while absence of thiamine allows S. cerevisiae to outcompete C. glabrata. This simplification of the THI pathway in C. glabrata suggests its environment provides thiamine and/or its precursors to cells, whereas S. cerevisiae is not as reliant on environmental sources of thiamine. PMID:27015653

  16. Oxidative stress response to menadione and cumene hydroperoxide in the opportunistic fungal pathogen Candida glabrata

    Directory of Open Access Journals (Sweden)

    Mayra Cuéllar-Cruz

    2009-07-01

    Full Text Available Candida glabrata is an opportunistic fungal pathogen that can cause severe invasive infections and can evade phagocytic cell clearance. We are interested in understanding the virulence of this fungal pathogen, in particular its oxidative stress response. Here we investigated C. glabrata, Saccharomyces cerevisiae and Candida albicans responses to two different oxidants: menadione and cumene hydroperoxide (CHP. In log-phase, in the presence of menadione, C. glabrata requires Cta1p (catalase, while in a stationary phase (SP, Cta1p is dispensable. In addition, C. glabrata is less resistant to menadione than C. albicans in SP. The S. cerevisiae laboratory reference strain is less resistant to menadione than C. glabrata and C. albicans; however S. cerevisiaeclinical isolates (CIs are more resistant than the lab reference strain. Furthermore, S. cerevisiae CIs showed an increased catalase activity. Interestingly, in SP C. glabrata and S. cerevisiae are more resistant to CHP than C. albicans and Cta1p plays no apparent role in detoxifying this oxidant.

  17. Neotropical planorbid snails with apertural lamellae: I. Biomphalaria helophila (Orbigny, 1835)

    OpenAIRE

    W. Lobato Paraense

    1996-01-01

    A definition of Biomphalaria helophila (Orbigny, 1835) is presented, based on examination of the shell and reproductive system of topotypic specimens and extended to a number of samples from other localities. The following nominal species and subspecies, collected from type localities, proved junior synonyms of B. helophila: Planorbis albicans Pfeiffer, 1839; Planorbis dentatus Gould, 1844; Planorbis dentiferus CB Adams, 1845; Planorbis dentiferus edentatus CB Adams, 1851; Planorbis dentiens ...

  18. Differentially expressed proteins in fluconazole-susceptible and fluconazole-resistant isolates of Candida glabrata.

    Science.gov (United States)

    Shen, Yinzhong; Zhang, Lijun; Jia, Xiaofang; Zhang, Yongxin; Lu, Hongzhou

    2015-06-01

    The current study aimed to identify the differences presented in the proteome of fluconazole-susceptible isolates of Candida glabrata compared to those with fluconazole-resistant ones. Two-dimensional differential gel electrophoresis was applied to identify proteins that were differentially expressed in fluconazole-susceptible and fluconazole-resistant isolates of C. glabrata. Eight proteins including aspartyl-tRNA synthetase, translation elongation factor 3, 3-phosphoglycerate kinase, ribosomal protein L5, coproporphyrinogen III oxidase, pyruvate kinase, G-beta like protein, and F1F0-ATPase alpha subunit were found to be more abundantly represented, while four proteins including vitamin B12-(cobalamin)-independent isozyme of methionine synthase, microtubule-associated protein, adenylosuccinate synthetase, and aldose reductase were found to be less abundantly represented in fluconazole-resistant strains versus those with fluconazole-susceptible ones. These differentially expressed proteins were primarily associated with energy metabolism, stress response, and macromolecule synthesis. Proteins associated with energy metabolism, stress response, and macromolecule synthesis may play a role in the development of fluconazole resistance in the clinical isolates of C. glabrata. Multiple different mechanisms are involved in the development of fluconazole resistance in C. glabrata. These findings provide a scientific basis for discovering new genes and mechanisms associated with fluconazole resistance in C. glabrata.

  19. A Murine Model of Candida glabrata Vaginitis Shows No Evidence of an Inflammatory Immunopathogenic Response.

    Directory of Open Access Journals (Sweden)

    Evelyn E Nash

    Full Text Available Candida glabrata is the second most common organism isolated from women with vulvovaginal candidiasis (VVC, particularly in women with uncontrolled diabetes mellitus. However, mechanisms involved in the pathogenesis of C. glabrata-associated VVC are unknown and have not been studied at any depth in animal models. The objective of this study was to evaluate host responses to infection following efforts to optimize a murine model of C. glabrata VVC. For this, various designs were evaluated for consistent experimental vaginal colonization (i.e., type 1 and type 2 diabetic mice, exogenous estrogen, varying inocula, and co-infection with C. albicans. Upon model optimization, vaginal fungal burden and polymorphonuclear neutrophil (PMN recruitment were assessed longitudinally over 21 days post-inoculation, together with vaginal concentrations of IL-1β, S100A8 alarmin, lactate dehydrogenase (LDH, and in vivo biofilm formation. Consistent and sustained vaginal colonization with C. glabrata was achieved in estrogenized streptozotocin-induced type 1 diabetic mice. Vaginal PMN infiltration was consistently low, with IL-1β, S100A8, and LDH concentrations similar to uninoculated mice. Biofilm formation was not detected in vivo, and co-infection with C. albicans did not induce synergistic immunopathogenic effects. This data suggests that experimental vaginal colonization of C. glabrata is not associated with an inflammatory immunopathogenic response or biofilm formation.

  20. Genome engineering in the yeast pathogen Candida glabrata using the CRISPR-Cas9 system

    Science.gov (United States)

    Enkler, Ludovic; Richer, Delphine; Marchand, Anthony L.; Ferrandon, Dominique; Jossinet, Fabrice

    2016-01-01

    Among Candida species, the opportunistic fungal pathogen Candida glabrata has become the second most common causative agent of candidiasis in the world and a major public health concern. Yet, few molecular tools and resources are available to explore the biology of C. glabrata and to better understand its virulence during infection. In this study, we describe a robust experimental strategy to generate loss-of-function mutants in C. glabrata. The procedure is based on the development of three main tools: (i) a recombinant strain of C. glabrata constitutively expressing the CRISPR-Cas9 system, (ii) an online program facilitating the selection of the most efficient guide RNAs for a given C. glabrata gene, and (iii) the identification of mutant strains by the Surveyor technique and sequencing. As a proof-of-concept, we have tested the virulence of some mutants in vivo in a Drosophila melanogaster infection model. Our results suggest that yps11 and a previously uncharacterized serine/threonine kinase are involved, directly or indirectly, in the ability of the pathogenic yeast to infect this model host organism. PMID:27767081

  1. Karyotyping of Candida albicans and Candida glabrata from patients with Candida sepsis.

    Science.gov (United States)

    Klempp-Selb, B; Rimek, D; Kappe, R

    2000-01-01

    The aim of this study was to determine the relatedness of Candida strains from patients suffering from Candida septicaemia by typing of Candida isolates from blood cultures and different body sites by pulsed field gel electrophoresis (PFGE using a contour-clamped homogenous electric field, CHEF). We studied 17 isolates of Candida albicans and 10 isolates of Candida glabrata from six patients. Four patients suffered from a C. albicans septicaemia, one patient from a C. glabrata septicaemia, and one patient had a mixed septicaemia with C. albicans and C. glabrata. Eight isolates from blood cultures were compared with 19 isolates of other sites (stool six, urine four, genital swab four, tip of central venous catheter three, tracheal secretion one, sputum one). PFGE typing resulted in 10 different patterns, four with C. albicans and six with C. glabrata. Five of the six patients had strains of identical PFGE patterns in the blood and at other sites. Seven isolates of a 58-year-old female with a C. glabrata septicaemia fell into five different PFGE patterns. However, they showed minor differences only, which may be due to chromosomal rearrangements within a single strain. Thus it appears, that the colonizing Candida strains were identical to the circulating strains in the bloodstream in at least five of six patients.

  2. Sorbic acid stress activates the Candida glabrata high osmolarity glycerol MAP kinase pathway

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    Zeljkica eJandric

    2013-11-01

    Full Text Available Weak organic acids such as sorbic acid are important food preservatives and powerful fungistatic agents. These compounds accumulate in the cytosol and disturb the cellular pH and energy homeostasis. Candida glabrata is in many aspects similar to Saccharomyces cerevisiae. However, with regard to confrontation to sorbic acid, two of the principal response pathways behave differently in Candida glabrata. In yeast, sorbic acid stress causes activation of many genes via the transcription factors Msn2 and Msn4. The C. glabrata homologues CgMsn2 and CgMsn4 are apparently not activated by sorbic acid. In contrast, in C. glabrata the high osmolarity glycerol (HOG pathway is activated by sorbic acid. Here we show that the MAP kinase of the HOG pathway, CgHog1, becomes phosphorylated and has a function for weak acid stress resistance. Transcript profiling of weak acid treated C. glabrata cells suggests a broad and very similar response pattern of cells lacking CgHog1 compared to wild type which is over lapping with but distinct from S. cerevisiae. The PDR12 gene was the highest induced gene in both species, and required CgHog1 for full expression. Our results support flexibility of the response cues for general stress signaling pathways, even between closely related yeasts, and functional extension of a specific response pathway.

  3. Local silencing controls the oxidative stress response and the multidrug resistance in Candida glabrata.

    Science.gov (United States)

    Orta-Zavalza, Emmanuel; Guerrero-Serrano, Gehenna; Gutiérrez-Escobedo, Guadalupe; Cañas-Villamar, Israel; Juárez-Cepeda, Jacqueline; Castaño, Irene; De Las Peñas, Alejandro

    2013-06-01

    In Candida glabrata, the sirtuins Sir2 and Hst1 control the expression of a wide number of genes including adhesins required for host colonization and niacin transporters needed for growth. Given that these sirtuins can be inactivated during infection, we asked if their inhibition could modify the response of C. glabrata to other stressful conditions. Here, we found that deletion of HST1 decreases susceptibility of C. glabrata to fluconazole and hydrogen peroxide. The transcription factor Pdr1 and the ABC transporter Cdr1 mediated the fluconazole resistance phenotype of the hst1Δ cells, whereas the transcriptional activator Msn4 and the catalase Cta1 are necessary to provide oxidative stress resistance. We show that the transcription factor Sum1 interacts with Hst1 and participate in the regulation of these genes. Interestingly, even though C. glabrata and Saccharomyces cerevisiae are closely related phylogenetically, deletion of HST1 decreased susceptibility to fluconazole and hydrogen peroxide only in C. glabrata but not in S. cerevisiae, indicating a different transcriptional control by two similar sirtuins. Our findings suggest that Hst1 acts as a regulator of stress resistance associated-genes. PMID:23651300

  4. Medical treatment of a pacemaker endocarditis due to Candida albicans and to Candida glabrata.

    Science.gov (United States)

    Roger, P M; Boissy, C; Gari-Toussaint, M; Foucher, R; Mondain, V; Vandenbos, F; le Fichoux, Y; Michiels, J F; Dellamonica, P

    2000-09-01

    We describe a case of pacemaker infection due to two fungal species: Candida albicans and C. glabrata. Transthoracic echocardiography showed a large vegetation on the intraventricular wires. Because of severe underlying diseases, surgery was believed to be contraindicated. The patient was treated using high dose of fluconazole, resulting in clinical improvement and negative blood cultures. However, 2 months later, the patient underwent a fatal stroke. At autopsy, a large vegetation was found only all along the wires. Postmortem culture of the infected material was positive for both C. albicans and C. glabrata. PMID:11023765

  5. Biomphalaria Tenagophila Guaibensis ssp. n. from Southern Brazil and Uruguay (pulmonata: Planorbidae. I. Morphology

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    W. Lobato Paraense

    1984-12-01

    Full Text Available A new subspecies of planorbid snail, biomphalaria tenagophila guaibensis, is described. It has been found along the coastal belt of the Brazilian state of rio grande do Sul and the middle part of Uruguay, from Porto Alegre to Mercedes. It differs from the nominate subspecies, Biomphalaria tenagophila tenagophila, in the appearance of the penial complex (prepuce longer and proportionally slenderer in B. t. guaibensis, shorter and proportionally stouter in b. t. tenagophila, in the ratio between the lengths of the penial sheath and the prepuce, in the ratio between the lengths of the uterine complex and the penial complex, and in a coefficient of difference of 2.44 for the ratio between the penis sheath and prepuce and of 2.02 for the ratio between the uterine complex and penial complex. The shell and the other organs of the genital system are similar in both subspecies. B. t. guaibensis is very similar to Biomphalaria occidentalis Paraense, 1981, but is readily separated from it by the presence of a vaginal pouch, which is lacking in the latter, besides showing highly significant difference in the penis sheath: prepuce and uterine complex: penial complex ratios. Crossbreeding experiments which lend additional support to the recognition of B. t. guaibensis as a subspecies will be reported elsewhere.É descrita uma nova subespécie de molusco planorbídeo, Biomphalaria tenagophila guaibensis, que tem sido encontrada ao longo da faixa costeira do Estado do Rio Grande do Sul e da parte média do Uruguai, de Porto Alegre a Mercedes. Distingue-se da espécie nominativa, Biomphalaria tenagophila tenagophila, pelo aspecto do complexo peniano (prepúcio mais longo e proporcionalmente mais delgado em B. t. guaibensis, mais curto e proporcionalmente mais grosso em b. t. tenagophila0, pela razão entre os comprimentos da bainha do pênis e do prepúcio, pela razão entre os comprimentos do complexo uterino e do complexo peniano, e por um coeficiente de

  6. Contribuição ao estudo da biologia de Biomphalaria occidentalis Paraense, 1981 e de Biomphalaria tenagophila (d'Orbigny, 1835, em condições de laboratório A contribution to the study of the biology of Biomphalaria occidentalis Paraense, 1981 and of Biomphalaria tenagophila (d'Orbigny, 1835, under laboratory conditions

    Directory of Open Access Journals (Sweden)

    Maísa Rose Domenico Elmor

    1992-10-01

    Full Text Available Com o objetivo de comparar a duração do período embrionário, a fecundidade e a fertilidade de Biomphalaria occidentalis Paraense, 1981 com a de B, tenagophila (d'Orbigny, 1835, exemplares de ambas as espécies foram criados em aquários dotados das mesmas características. Os ovos depostos pelos caramujos foram contados sob lupa binocular e seu desenvolvimento embrionário foi observado até a eclosão. Assim foi obtido o número total de posturas e de ovos por caramujo, bem como o número total de ovos eclodidos por postura para cada período de trinta dias, ou seja, a taxa de eclosão por período. O experimento teve a duração de doze meses e os resultados obtidos são válidos para condições de laboratório.Specimens of Biomphalaria occidentalis and Biomphalaria tenagophila were reared in S.Paulo, Brazil under laboratory conditions, with a view to know their biological characteristics. Oviposition and eggs/oviposition ratio were recorded over twelve months so as to obtain information on the number of egg-masses per animal and the number of eggs per egg-mass, as also the number of hatched eggs per egg-mass for each period of 30 days, i.e., the hatching-rate per period. The incubation period was about the same for both species, but the oviposition and egg oviposition ratio were greater in B. tenagophila.

  7. Susceptibility of Biomphalaria amazonica and Biomphalaria occidentalis from Manso Dam, Mato Grosso, Brazil to infection with three strains of Schistosoma mansoni

    Directory of Open Access Journals (Sweden)

    Monica Ammon Fernandez

    2006-10-01

    Full Text Available As well as malaria and yellow fever, schistosomiasis is one of the main endemic diseases associated to environments which suffered some impact related to the development of great economic projects, as for example the construction of hydroelectric power stations. Aiming to investigate the occurrence and distribution of freshwater snails of medical and veterinary importance in the area which suffered impact from the Manso hydroelectric power station a survey was performed during the period of 2002 to 2003 and revealed the occurrence of populations of Biomphalaria amazonica and Biomphalaria occidentalis. Studies on parasite-mollusc compatibility were undertaken using five B. amazonica colonies (Barão de Melgaço, Poconé, Santo Antônio do Leverger, and Chapada dos Guimarães, in the Manso and Casca rivers, and four B. occidentalis colonies (Cuiabá, Santo Antônio do Leverger, and Chapada dos Guimarães, in the Água Fria district and Casca river were exposed to miracidia of Schistosoma mansoni. Of 257 snails of B. amazonica used, 17 became infected (infection index of 6.61% and all specimens of B. occidentalis proved unsusceptible. According to the strains used, of the 158 snails exposed to BH miracidia, 6 became infected (3.79%; of the 44 exposed to SJ miracidia, 6 became infected (13.63%; and of the 55 snails of B. amazonica exposed to EC miracidia, 5 became infected (9.09%. These results point out the low possibility of introduction of schistosomiasis in those areas, but we believe it can not be discarded as due the presence of B. amazonica.

  8. Neotropical planorbid snails with apertural lamellae: I. Biomphalaria helophila (Orbigny, 1835

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    W Lobato Paraense

    1996-04-01

    Full Text Available A definition of Biomphalaria helophila (Orbigny, 1835 is presented, based on examination of the shell and reproductive system of topotypic specimens and extended to a number of samples from other localities. The following nominal species and subspecies, collected from type localities, proved junior synonyms of B. helophila: Planorbis albicans Pfeiffer, 1839; Planorbis dentatus Gould, 1844; Planorbis dentiferus CB Adams, 1845; Planorbis dentiferus edentatus CB Adams, 1851; Planorbis dentiens Morelet, 1849; Planorbula dentiens edentula Fischer & Crosse, 1880; Planorbis stagnicola Morelet, 1851; and Tropicorbis shimeki FC Baker, 1945. B. helophila was also identified in samples from Costa Rica, Guatemala, Haiti, Dominican Republic, Puerto Rico and Barbados.

  9. Failed Reverse Total Shoulder Arthroplasty Caused by Recurrent Candida glabrata Infection with Prior Serratia marcescens Coinfection

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    John G. Skedros

    2014-01-01

    Full Text Available This report describes a 58-year-old insulin-dependent diabetic male patient who initially sustained a proximal humerus fracture from a fall. The fracture fixation failed and then was converted to a humeral hemiarthroplasty, which became infected with Candida glabrata and Serratia marcescens. After these infections were believed to be cured with antibacterial and antifungal treatments and two-stage irrigation and debridement, he underwent conversion to a reverse total shoulder arthroplasty. Unfortunately, the C. glabrata infection recurred and, nearly 1.5 years after implantation of the reverse total shoulder, he had a resection arthroplasty (removal of all implants and cement. His surgical and pharmacologic treatment concluded with (1 placement of a tobramycin-impregnated cement spacer also loaded with amphotericin B, with no plan for revision arthroplasty (i.e., the spacer was chronically retained, and (2 chronic use of daily oral fluconazole. We located only three reported cases of Candida species causing infection in shoulder arthroplasties (two C. albicans, one C. parapsilosis. To our knowledge, a total shoulder arthroplasty infected with C. glabrata has not been reported, nor has a case of a C. glabrata and S. marcescens periprosthetic coinfection in any joint. In addition, it is well known that S. marcescens infections are uncommon in periprosthetic joint infections.

  10. Mini-chromosomes among danish Candida glabrata isolates originated through two different mechanisms

    DEFF Research Database (Denmark)

    Ahmad, K. M.; Ishchuk, O.; Hellborg, L.;

    2012-01-01

    We analyzed 201 strains of the pathogenic yeast Candida glabrata from patients, mainly suffering from systemic infection, at Danish hospitals during 1985 – 1999. Our analysis showed that these strains were closely related but exhibited large karyotype polymorphism. Nine strains contained mini...

  11. Formation of new chromosomes as a virulence mechanism in yeast Candida glabrata

    DEFF Research Database (Denmark)

    Poláková, S.; Blume, C.; Zárate, J. A.;

    2009-01-01

    , Candida glabrata, for their genome structure and stability. This organism has recently become the second most prevalent yeast pathogen in humans. Although the gene sequences were well conserved among different strains, their chromosome structures differed drastically. The most frequent events reshaping...

  12. Small chromosomes among Danish Candida glabrata isolates originated through different mechanisms

    DEFF Research Database (Denmark)

    Ahmad, Khadija Mohamed; Ishchuk, Olena P.; Hellborg, Linda;

    2013-01-01

    We analyzed 192 strains of the pathogenic yeast Candida glabrata from patients, mainly suffering from systemic infection, at Danish hospitals during 1985–1999. Our analysis showed that these strains were closely related but exhibited large karyotype polymorphism. Nine strains contained small...

  13. Amphotericin B and caspofungin resistance in Candida glabrata isolates recovered from a critically ill patient

    DEFF Research Database (Denmark)

    Krogh-Madsen, Mikkel; Arendrup, Maiken Cavling; Heslet, Lars;

    2006-01-01

    BACKGROUND: Consecutive Candida glabrata isolates recovered from a patient in an intensive care unit were resistant to amphotericin B (minimum inhibitory concentration, up to 32 mu g/mL; determined by Etest [AB Biodisk]). Analyses at the national reference laboratory showed that some isolates wer...

  14. The Drosophila Toll Pathway Controls but Does Not Clear Candida glabrata Infections

    NARCIS (Netherlands)

    Quintin, J.; Asmar, J.; Matskevich, A.A.; Lafarge, M.C.; Ferrandon, D.

    2013-01-01

    The pathogenicity of Candida glabrata to patients remains poorly understood for lack of convenient animal models to screen large numbers of mutants for altered virulence. In this study, we explore the minihost model Drosophila melanogaster from the dual perspective of host and pathogen. As in verteb

  15. Environmental azole fungicide, prochloraz, can induce cross-resistance to medical triazoles in Candida glabrata.

    Science.gov (United States)

    Faria-Ramos, Isabel; Tavares, Pedro R; Farinha, Sofia; Neves-Maia, João; Miranda, Isabel M; Silva, Raquel M; Estevinho, Letícia M; Pina-Vaz, Cidalia; Rodrigues, Acácio G

    2014-11-01

    Acquisition of azole resistance by clinically relevant yeasts in nature may result in a significant, yet undetermined, impact in human health. The main goal of this study was to assess the development of cross-resistance between agricultural and clinical azoles by Candida spp. An in vitro induction assay was performed, for a period of 90 days, with prochloraz (PCZ) - an agricultural antifungal. Afterward, the induced molecular resistance mechanisms were unveiled. MIC value of PCZ increased significantly in all Candida spp. isolates. However, only C. glabrata developed cross-resistance to fluconazole and posaconazole. The increased MIC values were stable. Candida glabrata azole resistance acquisition triggered by PCZ exposure involved the upregulation of the ATP binding cassette multidrug transporter genes and the transcription factor, PDR1. Single mutation previously implicated in azole resistance was found in PDR1 while ERG11 showed several synonymous single nucleotide polymorphisms. These results might explain why C. glabrata is so commonly less susceptible to clinical azoles, suggesting that its exposure to agricultural azole antifungals may be associated to the emergence of cross-resistance. Such studies forward potential explanations for the worldwide increasing clinical prevalence of C. glabrata and the associated worse prognosis of an infection by this species.

  16. A network of paralogous stress response transcription factors in the human pathogen Candida glabrata.

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    Jawad eMerhej

    2016-05-01

    Full Text Available The yeast Candida glabrata has become the second cause of systemic candidemia in humans. However, relatively few genome-wide studies have been conducted in this organism and our knowledge of its transcriptional regulatory network is quite limited. In the present work, we combined genome-wide chromatin immunoprecipitation (ChIP-seq, transcriptome analyses and DNA binding motif predictions to describe the regulatory interactions of the seven Yap (Yeast AP1 transcription factors of C. glabrata. We described a transcriptional network containing 255 regulatory interactions and 309 potential target genes. We predicted with high confidence the preferred DNA binding sites for 5 of the 7 CgYaps and showed a strong conservation of the Yap DNA binding properties between S. cerevisiae and C. glabrata. We provided reliable functional annotation for 3 of the 7 Yaps and identified for Yap1 and Yap5 a core regulon which is conserved in S. cerevisiae, C. glabrata and C. albicans. We uncovered new roles for CgYap7 in the regulation of iron-sulfur cluster biogenesis, for CgYap1 in the regulation of heme biosynthesis and for CgYap5 in the repression of GRX4 in response to iron starvation. These transcription factors define an interconnected transcriptional network at the cross-roads between redox homeostasis, oxygen consumption and iron metabolism.

  17. Impact of the age of Biomphalaria alexandrina snails on Schistosoma mansoni transmission: modulation of the genetic outcome and the internal defence system of the snail

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    Iman Fathy Abou-El-Naga

    2015-08-01

    Full Text Available Of the approximately 34 identified Biomphalariaspecies,Biomphalaria alexandrinarepresents the intermediate host of Schistosoma mansoniin Egypt. Using parasitological and SOD1 enzyme assay, this study aimed to elucidate the impact of the age of B. alexandrinasnails on their genetic variability and internal defence against S. mansoniinfection. Susceptible and resistant snails were reared individually for self-reproduction; four subgroups of their progeny were used in experiment. The young susceptible subgroup showed the highest infection rate, the shortest pre-patent period, the highest total cercarial production, the highest mortality rate and the lowest SOD1 activity. Among the young and adult susceptible subgroups, 8% and 26% were found to be resistant, indicating the inheritance of resistance alleles from parents. The adult resistant subgroup, however, contained only resistant snails and showed the highest enzyme activity. The complex interaction between snail age, genetic background and internal defence resulted in great variability in compatibility patterns, with the highest significant difference between young susceptible and adult resistant snails. The results demonstrate that resistance alleles function to a greater degree in adults, with higher SOD1 activity and provide potential implications for Biomphalariacontrol. The identification of the most susceptible snail age enables determination of the best timing for applying molluscicides. Moreover, adult resistant snails could be beneficial in biological snail control.

  18. Financial Intermediation

    OpenAIRE

    Gary Gorton; Andrew Winton

    2002-01-01

    The savings/investment process in capitalist economies is organized around financial intermediation, making them a central institution of economic growth. Financial intermediaries are firms that borrow from consumer/savers and lend to companies that need resources for investment. In contrast, in capital markets investors contract directly with firms, creating marketable securities. The prices of these securities are observable, while financial intermediaries are opaque. Why do financial inter...

  19. Intermediated Trade

    OpenAIRE

    Antras, Pol; Costinot, Arnaud

    2011-01-01

    This paper develops a simple model of international trade with intermediation. We consider an economy with two islands and two types of agents, farmers and traders. Farmers can produce two goods, but in order to sell these goods in centralized (Walrasian) markets, they need to be matched with a trader, and this entails costly search. In the absence of search frictions, our model reduces to a standard Ricardian model of trade. We use this simple model to contrast the implications of changes in...

  20. Upregulation of the Adhesin Gene EPA1 Mediated by PDR1 in Candida glabrata Leads to Enhanced Host Colonization.

    Science.gov (United States)

    Vale-Silva, Luis A; Moeckli, Beat; Torelli, Riccardo; Posteraro, Brunella; Sanguinetti, Maurizio; Sanglard, Dominique

    2016-01-01

    Candida glabrata is the second most common Candida species causing disseminated infection, after C. albicans. C. glabrata is intrinsically less susceptible to the widely used azole antifungal drugs and quickly develops secondary resistance. Resistance typically relies on drug efflux with transporters regulated by the transcription factor Pdr1. Gain-of-function (GOF) mutations in PDR1 lead to a hyperactive state and thus efflux transporter upregulation. Our laboratory has characterized a collection of C. glabrata clinical isolates in which azole resistance was found to correlate with increased virulence in vivo. Contributing phenotypes were the evasion of adhesion and phagocytosis by macrophages and an increased adhesion to epithelial cells. These phenotypes were found to be dependent on PDR1 GOF mutation and/or C. glabrata strain background. In the search for the molecular effectors, we found that PDR1 hyperactivity leads to overexpression of specific cell wall adhesins of C. glabrata. Further study revealed that EPA1 regulation, in particular, explained the increase in adherence to epithelial cells. Deleting EPA1 eliminates the increase in adherence in an in vitro model of interaction with epithelial cells. In a murine model of urinary tract infection, PDR1 hyperactivity conferred increased ability to colonize the bladder and kidneys in an EPA1-dependent way. In conclusion, this study establishes a relationship between PDR1 and the regulation of cell wall adhesins, an important virulence attribute of C. glabrata. Furthermore, our data show that PDR1 hyperactivity mediates increased adherence to host epithelial tissues both in vitro and in vivo through upregulation of the adhesin gene EPA1. IMPORTANCE Candida glabrata is an important fungal pathogen in human diseases and is also rapidly acquiring drug resistance. Drug resistance can be mediated by the transcriptional activator PDR1, and this results in the upregulation of multidrug transporters. Intriguingly

  1. Upregulation of the Adhesin Gene EPA1 Mediated by PDR1 in Candida glabrata Leads to Enhanced Host Colonization

    OpenAIRE

    Vale-Silva, Luis A.; Moeckli, Beat; Torelli, Riccardo; Posteraro, Brunella; Sanguinetti, Maurizio; Sanglard, Dominique

    2016-01-01

    ABSTRACT Candida glabrata is the second most common Candida species causing disseminated infection, after C. albicans. C. glabrata is intrinsically less susceptible to the widely used azole antifungal drugs and quickly develops secondary resistance. Resistance typically relies on drug efflux with transporters regulated by the transcription factor Pdr1. Gain-of-function (GOF) mutations in PDR1 lead to a hyperactive state and thus efflux transporter upregulation. Our laboratory has characterize...

  2. Modification of Biomphalaria straminea eggs enclose induced by gamma radiation; Modificacoes da eclosao de ovos de Biomphalaria straminea induzidas pela radiacao gama

    Energy Technology Data Exchange (ETDEWEB)

    Melo, A.M.M.A.; Leal, M.A.M.; Motta, M.A. da [Pernambuco Univ., Recife, PE (Brazil). Dept. de Biofisica e Radiobiologia

    1994-12-31

    A vector of Schistosomiasis, the mollusk Biomphalaria straminea, can procreate by means of sexual - when in colonies - or by hermaphrodite fecundation, if isolated. In order to study its reproductive behavior under gamma radiation, 540 snails kept in colony and 540 maintained isolated in individual aquariums, were irradiated with doses, 0, 2,5, 5,0, 7,5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 80, 160, 320 and 640 Gy of gamma-rays from a {sup 60} Co. source, and were observed during 30 days. Daily, the off spring were collected from the aquariums, its eggs counted and maintained in Petri`s plate, in water. After eight days, the eggs were counted again and the difference with the first count representing the hatched eggs. As a result, the eggs from the snails kept in colony showed a greater number of encloses than those from the isolated snails, ranging from 2,5 to 40 Gy. Beyond this dose the difference between the two observed groups were statistically non significant, leading to suppose a greater resistance of the sexually fecundation to the influence of gamma-rays. (author). 16 refs, 1 fig, 1 tab.

  3. New polymeric formulation for control of biomphalaria Alexandria based on pharmaceutical waste gelatin

    International Nuclear Information System (INIS)

    In the recent years, important new areas of application for plastics have emerged in medicine such as devices for the controlled release of drugs. The increases in the use of plastic materials in all sectors of industry have led to a continuous increase in the generation of plastic wastes. Recycling allow the waste to be reintroduced into the consumption cycle. Pharmaceutical companies which manufacture soft gels with different shapes, sizes and colors based mainly on gelatin formulations produce huge amount of gelatin waste. Schistosomiasis is one of the most important public health problems in our country. We now report the utilization of gelatin scrap by incorporating them in biodegradable films containing the molluscicide niclosamide for control of Biomphalaria Alexandrina snails. The preparation of the gelatin films will be described. The release of niclosamide from the prepared blends was investigated. The prepared formulations proved to be useful compared with free niclosamide

  4. Analgesic effect of leaf extract from Ageratina glabrata in the hot plate test

    Directory of Open Access Journals (Sweden)

    Guadalupe García P

    2011-10-01

    Full Text Available Ageratina glabrata (Kunth R.M. King & H. Rob., Asteraceae (syn. Eupatorium glabratum Kunth is widely distributed throughout Mexico and popularly known as "chamizo blanco" and "hierba del golpe" for its traditional use as external analgesic remedy. Though glabrata species has been chemically studied, there are no experimentally asserted reports about possible analgesic effects which can be inferred from its genus Ageratina. To fill the gap, we evaluated A. glabrata extracts in an animal model of nociception exploiting thermal stimuli. NMR and mass analyses identified a new thymol derivative, 10-benzoiloxy-6,8,9-trihydroxy-thymol isobutyrate (1, which was computationally converted into a ring-closed structure to explain interaction with the COX-2 enzyme in a ligand-receptor docking study. The resulting docked pose is in line with reported crystal complexes of COX-2 with chromene ligands. Based on the present results of dichloromethane extracts from its dried leaves, it is safe to utter that the plant possesses analgesic effects in animal tests which are mediated through inhibition of COX-2 enzyme.

  5. Biofilm formation in Candida glabrata: What have we learnt from functional genomics approaches?

    Science.gov (United States)

    d'Enfert, Christophe; Janbon, Guilhem

    2016-02-01

    Biofilms are a source of therapeutic failures because of their intrinsic tolerance to antimicrobials. Candida glabrata is one of the pathogenic yeasts that is responsible for life-threatening disseminated infections and able to form biofilms on medical devices such as vascular and urinary catheters. Recent progresses in the functional genomics of C. glabrata have been applied to the study of biofilm formation, revealing the contribution of an array of genes to this process. In particular, the Yak1 kinase and the Swi/Snf chromatin remodeling complex have been shown to relieve the repression exerted by subtelomeric silencing on the expression of the EPA6 and EPA7 genes, thus allowing the encoded adhesins to exert their key roles in biofilm formation. This provides a framework to evaluate the contribution of other genes that have been genetically linked to biofilm development and, based on the function of their orthologs in Saccharomyces cerevisiae, appear to have roles in adaptation to nutrient deprivation, calcium signaling, cell wall remodeling and adherence. Future studies combining the use of in vitro and animal models of biofilm formation, omics approaches and forward or reverse genetics are needed to expand the current knowledge of C. glabrata biofilm formation and reveal the mechanisms underlying their antifungal tolerance.

  6. Molluscicidal activity of Physalis angulata L. extracts and fractions on Biomphalaria tenagophila (d'Orbigny, 1835) under laboratory conditions

    OpenAIRE

    José Augusto A dos Santos; Therezinha Coelho B Tomassini; Deise Cristina Drummond Xavier; Ivone Maria Ribeiro; Melissa Teixeira G da Silva; Zenildo Buarque de Morais Filho

    2003-01-01

    The main objective of this research is to evaluate the molluscicide activity of Physalis angulata L. Biomphalaria tenagophila specimens under laboratory conditions. Extracts and fractions were supplied by the Laboratório de Química de Produtos Naturais, Farmanguinhos-Fiocruz. Experiments were performed according to the methodology described by the World Health Organization for molluscicide tests using the concentrations from 0.1 to 500 mg/l of the extracts, fractions and of a pool of physalin...

  7. Proteomic analysis of hyperadhesive Candida glabrata clinical isolates reveals a core wall proteome and differential incorporation of adhesins.

    Science.gov (United States)

    Gómez-Molero, Emilia; de Boer, Albert D; Dekker, Henk L; Moreno-Martínez, Ana; Kraneveld, Eef A; Ichsan; Chauhan, Neeraj; Weig, Michael; de Soet, Johannes J; de Koster, Chris G; Bader, Oliver; de Groot, Piet W J

    2015-12-01

    Attachment to human host tissues or abiotic medical devices is a key step in the development of infections by Candida glabrata. The genome of this pathogenic yeast codes for a large number of adhesins, but proteomic work using reference strains has shown incorporation of only few adhesins in the cell wall. By making inventories of the wall proteomes of hyperadhesive clinical isolates and reference strain CBS138 using mass spectrometry, we describe the cell wall proteome of C. glabrata and tested the hypothesis that hyperadhesive isolates display differential incorporation of adhesins. Two clinical strains (PEU382 and PEU427) were selected, which both were hyperadhesive to polystyrene and showed high surface hydrophobicity. Cell wall proteome analysis under biofilm-forming conditions identified a core proteome of about 20 proteins present in all C. glabrata strains. In addition, 12 adhesin-like wall proteins were identified in the hyperadherent strains, including six novel adhesins (Awp8-13) of which only Awp12 was also present in CBS138. We conclude that the hyperadhesive capacity of these two clinical C. glabrata isolates is correlated with increased and differential incorporation of cell wall adhesins. Future studies should elucidate the role of the identified proteins in the establishment of C. glabrata infections. PMID:26546455

  8. Role of glutathione in the oxidative stress response in the fungal pathogen Candida glabrata.

    Science.gov (United States)

    Gutiérrez-Escobedo, Guadalupe; Orta-Zavalza, Emmanuel; Castaño, Irene; De Las Peñas, Alejandro

    2013-08-01

    Candida glabrata, an opportunistic fungal pathogen, accounts for 18-26 % of all Candida systemic infections in the US. C. glabrata has a robust oxidative stress response (OSR) and in this work we characterized the role of glutathione (GSH), an essential tripeptide-like thiol-containing molecule required to keep the redox homeostasis and in the detoxification of metal ions. GSH is synthesized from glutamate, cysteine, and glycine by the sequential action of Gsh1 (γ-glutamyl-cysteine synthetase) and Gsh2 (glutathione synthetase) enzymes. We first screened for suppressor mutations that would allow growth in the absence of GSH1 (gsh1∆ background) and found a single point mutation in PRO2 (pro2-4), a gene that encodes a γ-glutamyl phosphate reductase and catalyzes the second step in the biosynthesis of proline. We demonstrate that GSH is important in the OSR since the gsh1∆ pro2-4 and gsh2∆ mutant strains are more sensitive to oxidative stress generated by H2O2 and menadione. GSH is also required for Cadmium tolerance. In the absence of Gsh1 and Gsh2, cells show decreased viability in stationary phase. Furthermore, C. glabrata does not contain Saccharomyces cerevisiae high affinity GSH transporter ortholog, ScOpt1/Hgt1, however, our genetic and biochemical experiments show that the gsh1∆ pro2-4 and gsh2∆ mutant strains are able to incorporate GSH from the medium. Finally, GSH and thioredoxin, which is a second redox system in the cell, are not essential for the catalase-independent adaptation response to H2O2. PMID:23455613

  9. Synergistic effects of tacrolimus and azole antifungal compounds in fluconazole-susceptible and fluconazole-resistant Candida glabrata isolates

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    Laura Bedin Denardi

    2015-03-01

    Full Text Available In vitro interaction between tacrolimus (FK506 and four azoles (fluconazole, ketoconazole, itraconazole and voriconazole against thirty clinical isolates of both fluconazole susceptible and -resistant Candida glabrata were evaluated by the checkerboard microdilution method. Synergistic, indifferent or antagonism interactions were found for combinations of the antifungal agents and FK506. A larger synergistic effect was observed for the combinations of FK506 with itraconazole and voriconazole (43%, followed by that of the combination with ketoconazole (37%, against fluconazole-susceptible isolates. For fluconazole-resistant C. glabrata, a higher synergistic effect was obtained from FK506 combined with ketoconazole (77%, itraconazole (73%, voriconazole (63% and fluconazole (60%. The synergisms that we observed in vitro, notably against fluconazole-resistant C. glabrata isolates, are promising and warrant further analysis of their applications in experimental in vivo studies.

  10. Heteroresistance to Fluconazole Is a Continuously Distributed Phenotype among Candida glabrata Clinical Strains Associated with In Vivo Persistence

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    Ronen Ben-Ami

    2016-08-01

    Full Text Available Candida glabrata causes persistent infections in patients treated with fluconazole and often acquires resistance following exposure to the drug. Here we found that clinical strains of C. glabrata exhibit cell-to-cell variation in drug response (heteroresistance. We used population analysis profiling (PAP to assess fluconazole heteroresistance (FLCHR and to ask if it is a binary trait or a continuous phenotype. Thirty (57.6% of 52 fluconazole-sensitive clinical C. glabrata isolates met accepted dichotomous criteria for FLCHR. However, quantitative grading of FLCHR by using the area under the PAP curve (AUC revealed a continuous distribution across a wide range of values, suggesting that all isolates exhibit some degree of heteroresistance. The AUC correlated with rhodamine 6G efflux and was associated with upregulation of the CDR1 and PDH1 genes, encoding ATP-binding cassette (ABC transmembrane transporters, implying that HetR populations exhibit higher levels of drug efflux. Highly FLCHRC. glabrata was recovered more frequently than nonheteroresistant C. glabrata from hematogenously infected immunocompetent mice following treatment with high-dose fluconazole (45.8% versus 15%, P = 0.029. Phylogenetic analysis revealed some phenotypic clustering but also variations in FLCHR within clonal groups, suggesting both genetic and epigenetic determinants of heteroresistance. Collectively, these results establish heteroresistance to fluconazole as a graded phenotype associated with ABC transporter upregulation and fluconazole efflux. Heteroresistance may explain the propensity of C. glabrata for persistent infection and the emergence of breakthrough resistance to fluconazole.

  11. Environmental Epidemiology of Intestinal Schistosomiasis in Uganda: Population Dynamics of Biomphalaria (Gastropoda: Planorbidae in Lake Albert and Lake Victoria with Observations on Natural Infections with Digenetic Trematodes

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    Candia Rowel

    2015-01-01

    Full Text Available This study documented the population dynamics of Biomphalaria and associated natural infections with digenetic trematodes, along the shores of Lake Albert and Lake Victoria, recording local physicochemical factors. Over a two-and-a-half-year study period with monthly sampling, physicochemical factors were measured at 12 survey sites and all freshwater snails were collected. Retained Biomphalaria were subsequently monitored in laboratory aquaria for shedding trematode cercariae, which were classified as either human infective (Schistosoma mansoni or nonhuman infective. The population dynamics of Biomphalaria differed by location and by lake and had positive relationship with pH (P<0.001 in both lakes and negative relationship with conductivity (P=0.04 in Lake Albert. Of the Biomphalaria collected in Lake Albert N=6,183, 8.9% were infected with digenetic trematodes of which 15.8% were shedding S. mansoni cercariae and 84.2% with nonhuman infective cercariae. In Lake Victoria, 2.1% of collected Biomphalaria  N=13,172 were infected with digenetic trematodes with 13.9% shedding S. mansoni cercariae, 85.7% shedding nonhuman infective cercariae, and 0.4% of infected snails shedding both types of cercariae. Upon morphological identification, species of Biomphalaria infected included B. sudanica, B. pfeifferi, and B. stanleyi in Lake Albert and B. sudanica, B. pfeifferi, and B. choanomphala in Lake Victoria. The study found the physicochemical factors that influenced Biomphalaria population and infections. The number and extent of snails shedding S. mansoni cercariae illustrate the high risk of transmission within these lake settings. For better control of this disease, greater effort should be placed on reducing environmental contamination by improvement of local water sanitation and hygiene.

  12. Ecotoxicological effect of sublethal exposure to zinc oxide nanoparticles on freshwater snail Biomphalaria alexandrina.

    Science.gov (United States)

    Fahmy, Sohair R; Abdel-Ghaffar, Fathy; Bakry, Fayez A; Sayed, Dawlat A

    2014-08-01

    Freshwater snails are used as sensitive biomarkers of aquatic ecosystem pollution. The potential impacts of zinc oxide nanoparticles (ZnONPs) on aquatic ecosystems have attracted special attention due to their unique properties. The present investigation was designed to evaluate the possible mechanisms of ecotoxicological effects of ZnONPs on freshwater snail Biomphalaria alexandrina. ZnONPs showed molluscicidal activity against B. alexandrina snails, and the LC50 was 145 μg/ml. Two tested concentrations of ZnONPs were selected: The first concentration was equivalent to LC10 (7 μg/ml), and the second was equivalent to LC25 (35 μg/ml). Exposure to ZnONPs (7 and 35 μg/ml) for three consecutive weeks significantly induced malondialdehyde and nitric oxide with concomitant decreases in glutathione and glutathione-S-transferase levels in hemolymph and soft tissues of treated snails. Moreover, ZnONPs elicited a significant decrease in total protein and albumin contents coinciding with enhancement of total lipids and cholesterol levels as well as activities of aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase in hemolymph and soft tissues of treated snails. This study highlights the potential ecological implications of ZnONP release in aquatic environments and may serve to encourage regulatory agencies in Egypt to more carefully monitor and regulate the industrial use and disposal of ZnONPs. PMID:24736985

  13. New scope on the relationship between rotifers and Biomphalaria alexandrina snails

    Institute of Scientific and Technical Information of China (English)

    Shereen Farouk Mossallam; Eglal Ibrahim Amer; Iman Fathy Abou-El-Naga

    2013-01-01

    Objective: To investigate the effect of rotifer internalization into snail tissue on the development of schistosomes. Methods:Susceptible laboratory-bred Biomphalaria alexandrina (B. alexandrina) snails were exposed to lab-maintained rotifers; Philodina spp., two weeks before and after being infected with Schistosoma mansoni (S. mansoni) miracidia. The consequent histopathological impact on snail tissues and cercarial biology were investigated before and after emergence from snails. Results:Contamination of B. alexandrina snails with philodina, two weeks before miracidial exposure, was found to hinder the preliminary development of S. mansoni cercariae inside the snail tissues. Furthermore, when snails were contaminated with rotifers two weeks post miracidial exposure; growth of already established cercariae was found to be retarded. The consequent influence of internalized rotifers within the snail tissue was clearly reflected on cercarial emergence, activity and infectivity along the four weeks duration of shedding. In the present study, comparison of snail histopathological findings and altered cercarial biology observed between the experimental and control groups indicated that the rotifers may have affected the levels of snail's energy reservoirs, which eventually was found to have had an adverse impact on reproduction, growth and survival of the parasite within the snail host, coupled with its performance outside the snail. Conclusions:In future biological control strategies of schistosomiasis, ritifers should be considered as a parasitic scourge of humanity.

  14. Spatial and seasonal trends of a natural population of Biomphalaria occidentalis in northeastern Argentina

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    Alejandra Rumi

    1992-06-01

    Full Text Available This study aims to analyze the age of a population of Biomphalaria occidentalis on a pound of Riachuelo river basin, wich is one of the three most important Middle Paraná river affluents in Corrientes province. Samples were drawn from three stations, were spatial and temporal numerical variations of the snail, as well as its relation with different environmental parameters, mainly temperature, rainfall, pH and conductivity, were analyzed. Snail abundance is given in number of individuals/hour. The differences between the three sampling stations, estimated by nonparametric tests, was nonsignificant. A relative scale to the greatest shell diameter was employed to build the age pyramids. Temporal fluctuations of snail abundance correlated negatively with the highest monthly accumulated temperatures (P < 0.05. Although different floristic compositions were observed at the three stations, no significant numerical variations were detected in B. occidentalis spatial distribution. Reproductive activity took place between March-April and November with overlapping cohort system. During summer (December-Febuary mortality increased along with temperature and reproductive activity was not evident.

  15. Force nanoscopy of hydrophobic interactions in the fungal pathogen Candida glabrata.

    Science.gov (United States)

    El-Kirat-Chatel, Sofiane; Beaussart, Audrey; Derclaye, Sylvie; Alsteens, David; Kucharíková, Soňa; Van Dijck, Patrick; Dufrêne, Yves F

    2015-02-24

    Candida glabrata is an opportunistic human fungal pathogen which binds to surfaces mainly through the Epa family of cell adhesion proteins. While some Epa proteins mediate specific lectin-like interactions with human epithelial cells, others promote adhesion and biofilm formation on plastic surfaces via nonspecific interactions that are not yet elucidated. We report the measurement of hydrophobic forces engaged in Epa6-mediated cell adhesion by means of atomic force microscopy (AFM). Using single-cell force spectroscopy, we found that C. glabrata wild-type (WT) cells attach to hydrophobic surfaces via strongly adhesive macromolecular bonds, while mutant cells impaired in Epa6 expression are weakly adhesive. Nanoscale mapping of yeast cells using AFM tips functionalized with hydrophobic groups shows that Epa6 is massively exposed on WT cells and conveys strong hydrophobic properties to the cell surface. Our results demonstrate that Epa6 mediates strong hydrophobic interactions, thereby providing a molecular basis for the ability of this adhesin to drive biofilm formation on abiotic surfaces.

  16. Roles of vacuolar H+-ATPase in the oxidative stress response of Candida glabrata.

    Science.gov (United States)

    Nishikawa, Hiroshi; Miyazaki, Taiga; Nakayama, Hironobu; Minematsu, Asuka; Yamauchi, Shunsuke; Yamashita, Kohei; Takazono, Takahiro; Shimamura, Shintaro; Nakamura, Shigeki; Izumikawa, Koichi; Yanagihara, Katsunori; Kohno, Shigeru; Mukae, Hiroshi

    2016-08-01

    Vacuolar H(+)-ATPase (V-ATPase) is responsible for the acidification of eukaryotic intracellular compartments and plays an important role in oxidative stress response (OSR), but its molecular bases are largely unknown. Here, we investigated how V-ATPase is involved in the OSR by using a strain lacking VPH2, which encodes an assembly factor of V-ATPase, in the pathogenic fungus Candida glabrata The loss of Vph2 resulted in increased H2O2 sensitivity and intracellular reactive oxygen species (ROS) level independently of mitochondrial functions. The Δvph2 mutant also displayed growth defects under alkaline conditions accompanied by the accumulation of intracellular ROS and these phenotypes were recovered in the presence of the ROS scavenger N-acetyl-l-cysteine. Both expression and activity levels of mitochondrial manganese superoxide dismutase (Sod2) and catalase (Cta1) were decreased in the Δvph2 mutant. Phenotypic analyses of strains lacking and overexpressing these genes revealed that Sod2 and Cta1 play a predominant role in endogenous and exogenous OSR, respectively. Furthermore, supplementation of copper and iron restored the expression of SOD2 specifically in the Δvph2 mutant, suggesting that the homeostasis of intracellular cupper and iron levels maintained by V-ATPase was important for the Sod2-mediated OSR. This report demonstrates novel roles of V-ATPase in the OSR in C. glabrata. PMID:27370212

  17. Proteomic analysis of hyperadhesive Candida glabrata clinical isolates reveals a core wall proteome and differential incorporation of adhesins

    NARCIS (Netherlands)

    E. Gómez-Molero; A.D. de Boer; H.L. Dekker; A. Moreno-Martínez; E.A. Kraneveld; . Ichsan; N. Chauhan; M. Weig; J.J. de Soet; C.G. de Koster; O. Bader; P.W.J. de Groot

    2015-01-01

    Attachment to human host tissues or abiotic medical devices is a key step in the development of infections by Candida glabrata. The genome of this pathogenic yeast codes for a large number of adhesins, but proteomic work using reference strains has shown incorporation of only few adhesins in the cel

  18. In vitro activity of essential oils extracted from condiments against fluconazole-resistant and -sensitive Candida glabrata.

    Science.gov (United States)

    Soares, I H; Loreto, É S; Rossato, L; Mario, D N; Venturini, T P; Baldissera, F; Santurio, J M; Alves, S H

    2015-09-01

    In the present study, the antifungal activity of essential oils obtained from Origanum vulgare (oregano), Cinnamomum zeylanicum (cinnamon), Lippia graveolens (Mexican oregano), Thymus vulgaris (thyme), Salvia officinalis (sage), Rosmarinus officinalis (rosemary), Ocimum basilicum (basil) and Zingiber officinale (ginger) were assessed against Candida glabrata isolates. One group contained 30 fluconazole-susceptible C. glabrata isolates, and the second group contained fluconazole-resistant isolates derived from the first group after the in vitro induction of fluconazole-resistance, for a total of 60 tested isolates. The broth microdilution methodology was used. Concentrations of 50μg/mL, 100μg/mL, 200μg/mL, 400μg/mL, 800μg/mL, 1600μg/mL and 3200μg/mL of the essential oils were used, and the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were determined. Thyme, sage, rosemary, basil and ginger essential oils showed no antifungal activity at the tested concentrations. Antimicrobial activity less than or equal to 3200μg/mL was observed for oregano, Mexican oregano and cinnamon essential oils. Both the oregano and Mexican oregano essential oils showed high levels of antifungal activity against the fluconazole-susceptible C. glabrata group, whereas the cinnamon essential oil showed the best antifungal activity against the fluconazole-resistant C. glabrata isolates. PMID:26281965

  19. Competitive Interactions between C. albicans, C. glabrata and C. krusei during Biofilm Formation and Development of Experimental Candidiasis.

    Science.gov (United States)

    Rossoni, Rodnei Dennis; Barbosa, Júnia Oliveira; Vilela, Simone Furgeri Godinho; dos Santos, Jéssica Diane; de Barros, Patrícia Pimentel; Prata, Márcia Cristina de Azevedo; Anbinder, Ana Lia; Fuchs, Beth Burgwyn; Jorge, Antonio Olavo Cardoso; Mylonakis, Eleftherios; Junqueira, Juliana Campos

    2015-01-01

    In this study, we evaluated the interactions between Candida albicans, Candida krusei and Candida glabrata in mixed infections. Initially, these interactions were studied in biofilms formed in vitro. CFU/mL values of C. albicans were lower in mixed biofilms when compared to the single biofilms, verifying 77% and 89% of C. albicans reduction when this species was associated with C. glabrata and C. krusei, respectively. After that, we expanded this study for in vivo host models of experimental candidiasis. G. mellonella larvae were inoculated with monotypic and heterotypic Candida suspensions for analysis of survival rate and quantification of fungal cells in the haemolymph. In the groups with single infections, 100% of the larvae died within 18 h after infection with C. albicans. However, interaction groups achieved 100% mortality after 72 h of infection by C. albicans-C. glabrata and 96 h of infection by C. albicans-C. krusei. C. albicans CFU/mL values from larvae hemolymph were lower in the interacting groups compared with the monoespecies group after 12 h of infection. In addition, immunosuppressed mice were also inoculated with monotypic and heterotypic microbial suspensions to induce oral candidiasis. C. albicans CFU/mL values recovered from oral cavity of mice were higher in the group with single infection by C. albicans than the groups with mixed infections by C. albicans-C. glabrata and C. albicans-C. krusei. Moreover, the group with single infection by C. albicans had a higher degree of hyphae and epithelial changes in the tongue dorsum than the groups with mixed infections. We concluded that single infections by C. albicans were more harmful for animal models than mixed infections with non-albicans species, suggesting that C. albicans establish competitive interactions with C. krusei and C. glabrata during biofilm formation and development of experimental candidiasis.

  20. The endocrine disruptor effect of the herbicides atrazine and glyphosate on Biomphalaria alexandrina snails.

    Science.gov (United States)

    Omran, Nahla Elsayed; Salama, Wesam Mohamed

    2016-04-01

    Atrazine (AZ) and glyphosate (GL) are herbicides that are widely applied to cereal crops in Egypt. The present study was designed to investigate the response of the snailBiomphalaria alexandrina(Mollusca: Gastropoda) as a bioindicator for endocrine disrupters in terms of steroid levels (testosterone (T) and 17β-estradiol (E)), alteration of microsomal CYP4501B1-like immunoreactivity, total protein (TP) level, and gonadal structure after exposure to sublethal concentrations of AZ or GL for 3 weeks. In order to study the ability of the snails' recuperation, the exposed snails were subjected to a recovery period for 2 weeks. The results showed that the level of T, E, and TP contents were significantly decreased (p ≤ 0.05) in both AZ- and GL-exposed groups compared with control (unexposed) group. The level of microsomal CYP4501B1-like immunoreactivity increased significantly (p ≤ 0.05) in GL- and AZ-exposed snails and reach nearly a 50% increase in AZ-exposed group. Histological investigation of the ovotestis showed that AZ and GL caused degenerative changes including azoospermia and oocytes deformation. Interestingly, all the recovered groups did not return back to their normal state. It can be concluded that both herbicides are endocrine disrupters and cause cellular toxicity indicated by the decrease of protein content and the increase in CYP4501B1-like immunoreactivity. This toxicity is irreversible and the snail is not able to recover its normal state. The fluctuation of CYP4501B1 suggests that this vertebrate-like enzyme may be functional also in the snail and may be used as a biomarker for insecticide toxicity.

  1. Effects of endosulfan and ethanol on the reproduction of the snail Biomphalaria tenagophila: a multigeneration study.

    Science.gov (United States)

    Oliveira-Filho, Eduardo Cyrino; Grisolia, Cesar Koppe; Paumgartten, Francisco Jose Roma

    2009-04-01

    Endosulfan (END) is an insecticide used in agriculture and as a wood preservative. Since END is practically insoluble in water, ethanol (ETOH) is often employed as a carrier solvent to spike it in the test medium in aquatic toxicity assays. In this study were investigated the effects of END and ETOH on the reproduction of the freshwater snail Biomphalaria tenagophila exposed over three successive generations. END (0, 0.001, 0.01, 0.1 mg L(-1)) was dissolved in the medium water using ETOH (up to 19.8 mg L(-1)) as carrier solvent. ETOH (19.8, 198, 1980 mg L(-1)) alone was tested as well. Adult snails (F(0)-generation) were exposed to END and ETOH for 8 weeks. The F(1)-generation continued to be exposed from embryo to reproductive maturity, while their descendants (F(2)) were exposed until day 10 after spawning. Effects on the fecundity (8-week production of eggs and egg-masses) of mature F(0) and F(1) snails were evaluated. Developmental toxicity was investigated in F(1) and F(2) embryos. END at the highest level tested (0.1 mg L(-1)) inhibited egg production by F(0) and F(1) snails. ETOH at levels 198 mg L(-1) also reduced fecundity of F(0) and F(1) an effect that was apparently aggravated by exposure over successive generations. END 0.1 mg L(-1) increased mortality and malformations and decreased hatching among F(1) embryos. ETOH drastically reduced the proportion of hatchings among F(2) embryos. The study-derived NOECs (no-observed-effect-concentrations) for END was 0.01 mg L(-1) (reduction in fecundity), and for ETOH were 19.8 mg L(-1) for reduction in fecundity and toxicity (hatching retardation).

  2. The endocrine disruptor effect of the herbicides atrazine and glyphosate on Biomphalaria alexandrina snails.

    Science.gov (United States)

    Omran, Nahla Elsayed; Salama, Wesam Mohamed

    2016-04-01

    Atrazine (AZ) and glyphosate (GL) are herbicides that are widely applied to cereal crops in Egypt. The present study was designed to investigate the response of the snailBiomphalaria alexandrina(Mollusca: Gastropoda) as a bioindicator for endocrine disrupters in terms of steroid levels (testosterone (T) and 17β-estradiol (E)), alteration of microsomal CYP4501B1-like immunoreactivity, total protein (TP) level, and gonadal structure after exposure to sublethal concentrations of AZ or GL for 3 weeks. In order to study the ability of the snails' recuperation, the exposed snails were subjected to a recovery period for 2 weeks. The results showed that the level of T, E, and TP contents were significantly decreased (p≤ 0.05) in both AZ- and GL-exposed groups compared with control (unexposed) group. The level of microsomal CYP4501B1-like immunoreactivity increased significantly (p≤ 0.05) in GL- and AZ-exposed snails and reach nearly a 50% increase in AZ-exposed group. Histological investigation of the ovotestis showed that AZ and GL caused degenerative changes including azoospermia and oocytes deformation. Interestingly, all the recovered groups did not return back to their normal state. It can be concluded that both herbicides are endocrine disrupters and cause cellular toxicity indicated by the decrease of protein content and the increase in CYP4501B1-like immunoreactivity. This toxicity is irreversible and the snail is not able to recover its normal state. The fluctuation of CYP4501B1 suggests that this vertebrate-like enzyme may be functional also in the snail and may be used as a biomarker for insecticide toxicity. PMID:24215068

  3. Levantamento planorbídico do Estado de São Paulo (Brasil: 4ª Região Administrativa Planorbidic survey of the 4th Administrative Region of the State of S. Paulo, Brazil

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    Jorge Faria Vaz

    1987-10-01

    Full Text Available A fim de conhecer a distribuição dos hospedeiros intermediários de S. mansoni no Estado de São Paulo (Brasil, a Superintendência de Controle de Endemias (SUCEN procedeu a amplo inquérito malacológico em todos os municípios paulistas que teve a duração de 4 anos. As pesquisas realizadas na 4ª Região Administrativa que tem sede em Sorocaba e que constituem o objeto do presente relato, mostraram que Biomphalaria tenagophila (d'Orbigny, 1835 ocorre em 26 dos 59 municípios nela compreendidos. Biomphalaria glabrata (Say, 1818 é encontrada em 9 municípios e Biomphalaria straminea (Dunker, 1848, em 2. Vários casos de esquistossomose em migrantes já foram observados na área estudada. B. tenagophila parece estar implicada na cadeia natural de transmissão de S. mansoni em Itu e em São Roque, municípios em que foram descobertos os dois únicos casos da doença, até agora considerados como autóctones em toda a região.In order to discover the actual distribution of the intermediate hosts of Schistosoma mansoni in the State of São Paulo, Brazil, a planorbidic survey was made in the 572 counties of the State. Investigation carried out in the State's 4th Administrative Region, which comprises 59 counties, has shown that Biomphalaria tenagophila (d'Orbigny, 1835, Biomphalaria glabrata (Say, 1818 and Biomphalaria straminea (Dunker, 1848 are found, respectively, in twenty nine, nine and two of the counties. Many cases of schistosomiasis were detected among migrants to the Region but, up to the present, only two patients - at Itu and São Roque - could have contracted, the disease in the studied area. It seems that the fluke was intermediated by B. tenagophila.

  4. Induction of ROS generation by fluconazole in Candida glabrata: activation of antioxidant enzymes and oxidative DNA damage.

    Science.gov (United States)

    Mahl, Camila Donato; Behling, Camile Saul; Hackenhaar, Fernanda S; de Carvalho e Silva, Mélany Natuane; Putti, Jordana; Salomon, Tiago B; Alves, Sydney Hartz; Fuentefria, Alexandre; Benfato, Mara S

    2015-07-01

    In this study, we assessed the generation of reactive oxygen species (ROS) induced by subinhibitory concentration of fluconazole in susceptible and resistant Candida glabrata strains at stationary growth phase and measured their oxidative responses parameters: glutathione peroxidase (GPx), superoxide dismutase (SOD), glutathione-S-transferase (GST), consumption of hydrogen peroxide, and total glutathione, as well as oxidative damage in lipids, proteins, and DNA. Data showed that fluconazole increased generation of ROS and GPx and SOD enzymatic activity in treated cells; however, these enzymatic activities did not differ between resistant and susceptible strains. Susceptible strains exhibited higher GST activity than resistant, and when susceptible cells were treated with fluconazole, GST activity decreased. Fluconazole treatment cause oxidative damage only in DNA. There are a possible participation of ROS, as organic peroxides and O2(•-), in antifungal mechanism of fluconazole, which results in higher GPx and SOD enzymatic activities and oxidative DNA damage in C. glabrata.

  5. Determination of quercetin, plumbagin and total flavonoids in Drosera peltata Smith var. glabrata Y.Z.Ruan

    OpenAIRE

    Yu He; Zhimin He; Feng He; Haitong Wan

    2012-01-01

    Background: Drosera peltata Smith var. glabrata Y.Z.Ruan, a kind of wild carnivorous plants in the family Droseraceae, has been used for the treatment of rheumatism and bruises in Chinese folk. None of compounds in this herb has been quantified in the previous studies. Objective: To develop a validated and reliable HPLC method for the simultaneous determination of two bioactive constituents - quercetin and plumbagin, and establish a simple UV spectrophotometry method for the analysis of total...

  6. Molluscicidal activity of Physalis angulata L. extracts and fractions on Biomphalaria tenagophila (d'Orbigny, 1835 under laboratory conditions

    Directory of Open Access Journals (Sweden)

    Santos José Augusto A dos

    2003-01-01

    Full Text Available The main objective of this research is to evaluate the molluscicide activity of Physalis angulata L. Biomphalaria tenagophila specimens under laboratory conditions. Extracts and fractions were supplied by the Laboratório de Química de Produtos Naturais, Farmanguinhos-Fiocruz. Experiments were performed according to the methodology described by the World Health Organization for molluscicide tests using the concentrations from 0.1 to 500 mg/l of the extracts, fractions and of a pool of physalins modified steroids present in this species. The results show that ethyl acetate and acetone extracts from the whole plant, the ethanolic extracts of the roots and the physalins pool from stems and leaves were active. Only the whole plant extracts were available in sufficient quantity for the determination of LD50 and LD90 values.

  7. Effect of tyrosol on adhesion of Candida albicans and Candida glabrata to acrylic surfaces.

    Science.gov (United States)

    Monteiro, Douglas Roberto; Feresin, Leonardo Perina; Arias, Laís Salomão; Barão, Valentim Adelino Ricardo; Barbosa, Debora Barros; Delbem, Alberto Carlos Botazzo

    2015-09-01

    The prevention of adhesion of Candida cells to acrylic surfaces can be regarded as an alternative to prevent denture stomatitis. The use of quorum sensing molecules, such as tyrosol, could potentially interfere with the adhesion process. Therefore, the aim of this study was to assess the effect of tyrosol on adhesion of single and mixed cultures of Candida albicans and Candida glabrata to acrylic resin surfaces. Tyrosol was diluted in each yeast inoculum (10(7) cells/ml in artificial saliva) at 25, 50, 100, and 200 mM. Then, each dilution was added to wells of 24-well plates containing the acrylic specimens, and the plates were incubated at 37°C for 2 h. After, the effect of tyrosol was determined by total biomass quantification, metabolic activity of the cells and colony-forming unit counting. Chlorhexidine gluconate (CHG) was used as a positive control. Data were analyzed using analysis of variance (ANOVA) and the Holm-Sidak post hoc test (α = 0.05). The results of total biomass quantification and metabolic activity revealed that the tyrosol promoted significant reductions (ranging from 22.32 to 86.16%) on single C. albicans and mixed cultures. Moreover, tyrosol at 200 mM and CHG significantly reduced (p Candida adhesion to acrylic resin, and further investigations are warranted to clarify its potential against Candida infections.

  8. Ocorrência de Biomphalaria straminea (Pulmonata: Planorbidae na estação de aqüicultura do IBAMA em Uberlândia, MG

    Directory of Open Access Journals (Sweden)

    Elisângela de Paula Silveira

    1997-10-01

    Full Text Available Este trabalho avalia a ocorrência de moluscos planorbídeos na estação de psicultura do IBAMA em Uberlândia, Minas Gerais. Constatou-se a presença de Biomphalaria straminea em 39,5% dos tanques de criação. Nenhum dos caramujos estava infectado por Schistosoma mansoni, mas investigações complementares devem ser realizadas na área.This work evaluates the occurrence of freshwater snails in the IBAMA's fish breeding station in Uberlandia, Minas Gerais State. We verified the presence of Biomphalaria straminea in 39.5% of all breeding tanks. None of the snails were infected by Schistosoma mansoni, but futher investigation should be done in the area.

  9. Overexpression of Aldo-Keto-Reductase in Azole-resistant Clinical Isolates of Candida Glabrata Determined by cDNA-AFLP

    Directory of Open Access Journals (Sweden)

    Mansour Heidari

    2013-01-01

    Full Text Available Background: Candida glabrata causes significant medical problems in immunocompromised patients. Many strains of this yeast are intrinsically resistant to azole antifungal agents, and treatment is problematic, leading to high morbidity and mortality rates in immunosuppressed individuals. The primary goal of this study was to investigate the genes involved in the drug resistance of clinical isolates of C. glabrata.Methods: The clinical isolates of C. glabrata were collected in an epidemiological survey of candidal infection inimmunocompromised patients and consisted of four fluconazole and itraconazole resistant isolates, two fluconazoleand itraconazole sensitive isolates, and C. glabrata CBS 138 as reference strain. Antifungal susceptibility patterns ofthe organisms were determined beforehand by the Clinical and Laboratory Standards Institute (CLSI. The potentialgene(s implicated in antifungal resistance were investigated using complementary DNA- Amplified Fragment Length Polymorphism (cDNA-AFLP. Semi-quantitative RT-PCR was carried out to evaluate the expression of gene(s in resistant isolates as compared to sensitive and reference strains.Results and conclusions: The aldo-keto-reductase superfamily (AKR gene was upregulated in the resistant clinicalisolates as assessed by cDNA-AFLP. Semi-quantitative RT-PCR revealed AKR mRNA expression approximately twice that seen in the sensitive isolates. Overexpression of the AKR gene was associated with increased fluconazole and itraconazole resistance in C. glabrata. The data suggest that upregulation of the AKR gene might give a new insight into the mechanism of azole resistance.

  10. The fate of linear DNA in Saccharomyces cerevisiae and Candida glabrata: the role of homologous and non-homologous end joining.

    Directory of Open Access Journals (Sweden)

    Mary W Corrigan

    Full Text Available In vivo assembly of plasmids has become an increasingly used process, as high throughput studies in molecular biology seek to examine gene function. In this study, we investigated the plasmid construction technique called gap repair cloning (GRC in two closely related species of yeast - Saccharomyces cerevisiae and Candida glabrata. GRC utilizes homologous recombination (HR activity to join a linear vector and a linear piece of DNA that contains base pair homology. We demonstrate that a minimum of 20 bp of homology on each side of the linear DNA is required for GRC to occur with at least 10% efficiency. Between the two species, we determine that S. cerevisiae is slightly more efficient at performing GRC. GRC is less efficient in rad52 deletion mutants, which are defective in HR in both species. In dnl4 deletion mutants, which perform less non-homologous end joining (NHEJ, the frequency of GRC increases in C. glabrata, whereas GRC frequency only minimally increases in S. cerevisiae, suggesting that NHEJ is more prevalent in C. glabrata. Our studies allow for a model of the fate of linear DNA when transformed into yeast cells. This model is not the same for both species. Most significantly, during GRC, C. glabrata performs NHEJ activity at a detectable rate (>5%, while S. cerevisiae does not. Our model suggests that S. cerevisiae is more efficient at HR because NHEJ is less prevalent than in C. glabrata. This work demonstrates the determinants for GRC and that while C. glabrata has a lower efficiency of GRC, this species still provides a viable option for GRC.

  11. [Dynamic transmission of Schistosoma by Biomphalaria pfeifferi in the region of Man in Côte d'Ivoire].

    Science.gov (United States)

    Yapi Yapi, G; Touré, M; Boka, O M; Tia, E; Boby, O A-M

    2014-12-01

    Intestinal schistosomiasis by Schistosoma mansoni is a parasitary affection transmitted in West Africa by the mollusc Biomphalaria pfeifferi. Transmission dynamic of schistosomiasis by Biomphalaria pfeifferi has seldom been investigated in Côte d'Ivoire. In the framework of a research project on the epidemiology of schistosomiasis in the natural forest ecosystems, this study was performed longitudinally over a period of three years in Man region, in western Côte d'Ivoire. The trial set up from 1986 to 1989 and the project was funded by the World Health Organization. The general objective is to design a strategy of schistosomiasis control based on chemotherapy. The approach aims at interrupting or considerably reducing the reinfections, prolonging in that way the duration of the positive effects of the chemotherapy. The specific objectives assigned to the work consisted in studying the dynamic of the B. pfeifferi population and the infection of B. pfeifferi. To achieve our objectives, diverse methods (i: the molluscs sampling by two prospectors during 15 minutes per study site and ii: individual isolation of molluscs in test tubes with 5 or 10 mL of filtered water and exposure to light) have been used. They enabled us in the sampling of the intermediary host molluscs of Schistosoma and seek their infections. The results show that apparent high densities of B. pfeifferi can be observed at the end of the dry season and at the beginning of rainy seasons. In addition, the variation of relative abundance of intermediary host molluscs of Schistosoma is significantly influenced by rainfall and the system of water ways. The period of transmission of the infection to man is six months at Gueupleu village and ten months at Botonguiné village. In order to optimize the effect of chemotherapy in these sites of transmission characterized by a high level of endemy (68 %), an extreme mobility of human populations and a multiplicity of contamination sites, this study should not

  12. Bacterial intermediate filaments

    DEFF Research Database (Denmark)

    Charbon, Godefroid; Cabeen, M.; Jacobs-Wagner, C.

    2009-01-01

    Crescentin, which is the founding member of a rapidly growing family of bacterial cytoskeletal proteins, was previously proposed to resemble eukaryotic intermediate filament (IF) proteins based on structural prediction and in vitro polymerization properties. Here, we demonstrate that crescentin...

  13. Intermediate algebra a textworkbook

    CERN Document Server

    McKeague, Charles P

    1985-01-01

    Intermediate Algebra: A Text/Workbook, Second Edition focuses on the principles, operations, and approaches involved in intermediate algebra. The publication first takes a look at basic properties and definitions, first-degree equations and inequalities, and exponents and polynomials. Discussions focus on properties of exponents, polynomials, sums, and differences, multiplication of polynomials, inequalities involving absolute value, word problems, first-degree inequalities, real numbers, opposites, reciprocals, and absolute value, and addition and subtraction of real numbers. The text then ex

  14. Intermediate algebra & analytic geometry

    CERN Document Server

    Gondin, William R

    1967-01-01

    Intermediate Algebra & Analytic Geometry Made Simple focuses on the principles, processes, calculations, and methodologies involved in intermediate algebra and analytic geometry. The publication first offers information on linear equations in two unknowns and variables, functions, and graphs. Discussions focus on graphic interpretations, explicit and implicit functions, first quadrant graphs, variables and functions, determinate and indeterminate systems, independent and dependent equations, and defective and redundant systems. The text then examines quadratic equations in one variable, system

  15. Contribuição ao estudo da biologia de Biomphalaria occidentalis Paraense, 1981 e de Biomphalaria tenagophila (d'Orbigny, 1835, em condições de laboratório

    Directory of Open Access Journals (Sweden)

    Maísa Rose Domenico Elmor

    1992-10-01

    Full Text Available Com o objetivo de comparar a duração do período embrionário, a fecundidade e a fertilidade de Biomphalaria occidentalis Paraense, 1981 com a de B, tenagophila (d'Orbigny, 1835, exemplares de ambas as espécies foram criados em aquários dotados das mesmas características. Os ovos depostos pelos caramujos foram contados sob lupa binocular e seu desenvolvimento embrionário foi observado até a eclosão. Assim foi obtido o número total de posturas e de ovos por caramujo, bem como o número total de ovos eclodidos por postura para cada período de trinta dias, ou seja, a taxa de eclosão por período. O experimento teve a duração de doze meses e os resultados obtidos são válidos para condições de laboratório.

  16. Antidiarrheal Thymol Derivatives from Ageratina glabrata. Structure and Absolute Configuration of 10-Benzoyloxy-8,9-epoxy-6-hydroxythymol Isobutyrate

    Directory of Open Access Journals (Sweden)

    Celia Bustos-Brito

    2016-09-01

    Full Text Available Chemical investigation of the leaves from Ageratina glabrata yielded four new thymol derivatives, namely: 10-benzoyloxy-8,9-dehydro-6-hydroxythymol isobutyrate (4, 10-benzoyloxy-8,9-dehydrothymol (5, 10-benzoyloxythymol (6 and 10-benzoyloxy-6,8-dihydroxy-9-isobutyryl-oxythymol (7. In addition, (8S-10-benzoyloxy-8,9-epoxy-6-hydroxythymol isobutyrate (1, together with other two already known thymol derivatives identified as 10-benzoyloxy-8,9-epoxy-6-methoxythymol isobutyrate (2 and 10-benzoyloxy-8,9-epoxythymol isobutyrate (3 were also obtained. In this paper, we report the structures and complete assignments of the 1H and 13C-NMR data of compounds 1–7, and the absolute configuration for compound 1, unambiguously established by single crystal X-ray diffraction, and evaluation of the Flack parameter. The in vitro antiprotozoal assay showed that compound 1 and its derivative 1a were the most potent antiamoebic and antigiardial compounds. Both compounds showed selectivity and good antiamoebic activity comparable to emetine and metronidazole, respectively, two antiprotozoal drugs used as positive controls. In relation to anti-propulsive effect, compound 1 and 1a showed inhibitory activity, with activities comparable to quercetin and compound 9, two natural antipropulsive compounds used as positive controls. These data suggest that compound 1 may play an important role in antidiarrheal properties of Ageratina glabrata.

  17. Identification of signature volatiles to discriminate Candida albicans, glabrata, krusei and tropicalis using gas chromatography and mass spectrometry.

    Science.gov (United States)

    Hertel, Moritz; Hartwig, Stefan; Schütte, Eyke; Gillissen, Bernhard; Preissner, Robert; Schmidt-Westhausen, Andrea Maria; Paris, Sebastian; Kastner, Isabell; Preissner, Saskia

    2016-02-01

    Oral candidiasis is the most frequent fungal infection of the oral cavity. Clinical diagnoses require mycological confirmation, which is time-consuming in case of culture testing. The aim of the study was to identify signature volatiles to develop a chairside breath test to diagnose oral candidiasis. Headspaces above Candida albicans, glabrata, tropicalis, krusei cultures, and growth media as control were analysed after eight and 24 h using offline gas chromatography and mass spectrometry. The identification of signature volatiles was assisted using various microbial databases. Retrieved volatile patterns enabled Candida species discrimination in vitro. For C. albicans 3-methyl-2-butanone and styrene and for C. krusei a combination of p-xylene, 2-octanone, 2-heptanone and n-butyl acetate were found to be specific. 1-hexanol was found in C. tropicalis, but is emitted by a variety of other microorganisms. C. glabrata was characterised through the absence of these volatiles. The development of a breath test is a promising approach in confirming suspicions of oral candidiasis. To confirm the retrieved results in vivo, breath tests in affected and healthy subjects have to be performed.

  18. Transcription factors Asg1p and Hal9p regulate pH homeostasis in Candida glabrata

    Directory of Open Access Journals (Sweden)

    Jing eWu

    2015-08-01

    Full Text Available Candida glabrata is an important microorganism used in commercial fermentation to produce pyruvate, but very little is known about its mechanisms for surviving acid stress in culture. In this study, it was shown that transcription factors Asg1p and Hal9p play essential roles in C. glabrata in the tolerance of acid stress, as the deletion of CgASG1 or CgHAL9 resulted in the inability to survive in an acidic environment. Cgasg1 and Cghal9 mutant strains are unable to maintain pH homeostasis, as evidenced by a decrease in intracellular pH and an increase in reactive oxygen species production, which results in metabolic disorders. The results showed that intracellular acidification was partly due to the diminished activity of the plasma membrane proton pump, CgPma1p. In addition, transcriptome sequencing revealed that Cgasg1 and Cghal9 mutant strains displayed a variety of changes in gene expression under acidic conditions, including genes in the MAPK signaling pathway, plasma membrane or cell wall organization, trehalose accumulation, and the RIM101 signaling pathway. Lastly, quantitative reverse-transcribed PCR and cellular localization showed that CgAsg1p and CgHal9p played independent roles in response to acid stress.

  19. Biomphalaria tenagophila potencial vector of Schistosoma mansoni in the Paraná River basin (Argentina and Paraguay).

    Science.gov (United States)

    Borda, C Edgardo; Rea, María Josefa F

    2007-05-01

    Susceptibility and compatibility experiments were carried out with 700 Biomphalaria tenagophila from the Paraná River basin exposed to infection with Schistosoma mansoni. Individual infection was performed with 10 miracidia of SJ2 strain from the Paraiba valley (Brazil) originally infective to B. tenagophila. These snails were laboratory-breed progeny of B. tenagophila collected from six localities of Argentina and one from Paraguay. From Argentina: Rincón de Vences (7%) and Posadas (11%) became infected with S. mansoni and the calculation of Frandsen's index (TCP/100) shows that they were Class II poorly compatible. Those snails from Goya (22%), Maloyas (5%), and Berón de Astrada (3%) were Class III compatible to the S. mansoni. None of the 100 snails exposed from Caá-Catí became infected (Class 0 incompatible). Tested samples from Paraguay (Encarnación) were infected (20%) and compatible (Class III). It was also studied the persistence of the infection in 244 snails of the first generation (F1) of those that were susceptible from three places. It was demonstrated an increment of the susceptibility in the F1 from Maloyas (chi2 = 27.22; p = 0.0001) and Posadas (chi2 = 4.24; p = 0.04). The results point out the possibility that schistosomiasis might be able to spread into the Paraná River basin where B. tenagophila exists.

  20. Correlation between steroid sex hormones, egg laying capacity and cercarial shedding in Biomphalaria alexandrina snails after treatment with Haplophyllum tuberculatum.

    Science.gov (United States)

    Rizk, Maha Z; Metwally, Nadia S; Hamed, Manal A; Mohamed, Azza M

    2012-10-01

    Schistosomiasis is considered the second most pre-valiant worldwide parasitic disease ranked next to malaria. It has significant economic and public health consequences in many developing countries. Several ways have been practiced in order to bring the disease under an adequate control through the breakage of the life cycle of the parasite. Snail control could be regarded as a rapid and efficient of reducing or eliminating transmission and remains among the methods of choice for schistosomiasis control. The aim of this work is to evaluate the role of Haplophyllum tuberculatum (family Rutaceae) as a plant molluscicide. The mortality rate of Biomphalaria alexandrina snails were monitored after treatment with three extracts of the plant aerial parts; petroleum ether, chloroform and ethanol. Chloroform extract that recorded the most potent effect was further evaluated through measuring the toxicity pattern against B. alexandrina snails, egg laying capacity, cercarial shedding, phenol oxidase enzyme and the levels of steroid sex hormones. Histopathological examination of hepatopancreas and ovotestis of treated snails were also done for result confirmation. Treatment of snails by chloroform extract recorded reduction in egg laying capacity, decrease in cercarial shedding, diminution in phenol oxidase enzyme, disturbance in steroid sex hormones and sever alternation of the histopathological picture of snails tissue. In conclusion, H. tuberculatum recorded molluscicidal potency against B. alexandrina snails. Further studies are needed for its environmental applications. PMID:22771439

  1. Sublethal Effects of Some New Textile Dyes On the Freshwater Snail Biomphalaria alexandrina, as a Biological Indicator

    International Nuclear Information System (INIS)

    The Eco toxicological effects of three synthetic textile dyes; fast violet (FV), fast orange (FO) and fast yellow (FY) which mainly used in textile industry in Egypt, were tested on the freshwater snail Biomphalaria alexandrina, that used as a bio-indicator. The results demonstrated that only the FV dye is lethal and the 72 hr LC 50 is 500 ppm. The FO and dyes did not show any lethal effect on the snails at the concentrations used throughout the experiment time. The sublethal toxic concentration of non-irradiated FV dye (100 ppm) showed an increase in cellular and humoral defense responses of the snails exposed to the dye for 72 hr. Although the profile of the snail's nucleoproteins revealed minor qualitative differences; were quantitative differences differences reflected in the intensity of the separated bands, as well as, the percentage of the protein content. The protein content significantly decreased in the snails exposed to FV-dye when compared to FO,FY and non-exposed control snails

  2. Aspectos imunológicos e parasitológicos em Biomphalaria tenagophila infectadas por Schistosoma mansoni e outros Digenea

    Directory of Open Access Journals (Sweden)

    Balan Doralice de Souza Luro

    1993-01-01

    Full Text Available Estudou-se o comportamento de amebócitos de Biomphalaria tenagophila infectadas por Schistosoma mansoni, por outros Digenea e a resistência à superinfecção, presente em infecções mistas. Foi verificada a atividade fagocitária dos amebócitos, o número destas células circulantes, a reação amebocitária nos tecidos, o perfil eletroforético da hemolinfa, além da reação de imunodifusão. Concluiu-se que moluscos infectados por outros Digenea apresentam resistência à superinfecção por S. mansoni, sendo que os amebócitos parecem não ter participação direta na destruição dos esporocistos de S. mansoni nesta eventualidade. Nos moluscos infectados observou-se maior número de amebócitos circulantes e aumento de capacidade fagocitária destas células.

  3. Comparative Study of the Molluscicidal Activity of Some Plant Extracts on the Snail Vector of Schistosoma mansoni, Biomphalaria alexandrina

    Directory of Open Access Journals (Sweden)

    M. Al-Hazmi

    2011-01-01

    Full Text Available Schistosomiasis is considered as one of the most important trematode disease of man. The most important goal of the present study is to use the natural plants as cheaper and available sources for snail control. The present investigation concerned with the evaluation of toxicological, biological and physiological effects of water suspension, cold water and boiled water extracts of Agave filifera whole plant, Ammi majus flowers and leaves and Canna indica flowers and leaves comparing with the effect of different sulphate compounds. The present work revealed that, copper sulphate as well as the water suspension of Ammi majus flowers and leaves disclosed the most potent effect on the cumulative mortality after 6 weeks exposure periods. Also, egg laying capacity and egg hatchability of Biomphalaria alexandrina snails were affected with the exposure to CuSO4 and water suspension of Ammi majus flowers. The sublethal doses (LC10 of copper sulphate and water suspension of the tested plants reduced the total protein and total lipid contents of the hemolymph of B. alexandrina snails. The activity of transaminases enzymes as well as acetylcholinesterase had been affected by the exposure to the sublethal doses of copper sulphate and the water suspension of the tested plants. Also, histopathological changes were recorded in hermaphrodite gland of B. alexandrina snails post 6 weeks of exposure.

  4. Biomphalaria tenagophila potencial vector of Schistosoma mansoni in the Paraná River basin (Argentina and Paraguay

    Directory of Open Access Journals (Sweden)

    C Edgardo Borda

    2007-03-01

    Full Text Available Susceptibility and compatibility experiments were carried out with 700 Biomphalaria tenagophila from the Paraná River basin exposed to infection with Schistosoma mansoni. Individual infection was performed with 10 miracidia of SJ2 strain from the Paraiba valley (Brazil originally infective to B. tenagophila. These snails were laboratory-breed progeny of B. tenagophila collected from six localities of Argentina and one from Paraguay. From Argentina: Rincón de Vences (7% and Posadas (11% became infected with S. mansoni and the calculation of Frandsen's index (TCP/100 shows that they were Class II poorly compatible. Those snails from Goya (22%, Maloyas (5%, and Berón de Astrada (3% were Class III compatible to the S. mansoni. None of the 100 snails exposed from Caá-Catí became infected (Class 0 incompatible. Tested samples from Paraguay (Encarnación were infected (20% and compatible (Class III. It was also studied the persistence of the infection in 244 snails of the first generation (F1 of those that were susceptible from three places. It was demonstrated an increment of the susceptibility in the F1 from Maloyas (chi2 = 27.22; p = 0.0001 and Posadas (chi2 = 4.24; p = 0.04. The results point out the possibility that schistosomiasis might be able to spread into the Paraná River basin where B. tenagophila exists.

  5. Mobile communication and intermediality

    DEFF Research Database (Denmark)

    Helles, Rasmus

    2013-01-01

    The article argues the importance of intermediality as a concept for research in mobile communication and media. The constant availability of several, partially overlapping channels for communication (texting, calls, email, Facebook, etc.) requires that we adopt an integrated view of the various...... communicative affordances of mobile devices in order to understand how people choose between them for different purposes. It is argued that mobile communication makes intermediality especially central, as the choice of medium is detached from the location of stationary media and begins to follow the user across...

  6. Identification of Components of the SUMOylation Machinery in Candida glabrata: ROLE OF THE DESUMOYLATION PEPTIDASE CgUlp2 IN VIRULENCE.

    Science.gov (United States)

    Gujjula, Rahul; Veeraiah, Sangeetha; Kumar, Kundan; Thakur, Suman S; Mishra, Krishnaveni; Kaur, Rupinder

    2016-09-01

    Regulation of protein function by reversible post-translational modification, SUMOylation, is widely conserved in the eukaryotic kingdom. SUMOylation is essential for cell growth, division, and adaptation to stress in most organisms, including fungi. As these are key factors in determination of fungal virulence, in this study, we have investigated the importance of SUMOylation in the human pathogen, Candida glabrata We identified the enzymes involved in small ubiquitin-like modifier conjugation and show that there is strong conservation between Saccharomyces cerevisiae and C. glabrata We demonstrate that SUMOylation is an essential process and that adaptation to stress involves changes in global SUMOylation in C. glabrata Importantly, loss of the deSUMOylating enzyme CgUlp2 leads to highly reduced small ubiquitin-like modifier protein levels, and impaired growth, sensitivity to multiple stress conditions, reduced adherence to epithelial cells, and poor colonization of specific tissues in mice. Our study thus demonstrates a key role for protein SUMOylation in the life cycle and pathobiology of C. glabrata.

  7. Water oxidation: Intermediate identification

    Science.gov (United States)

    Cowan, Alexander J.

    2016-08-01

    The slow kinetics of light-driven water oxidation on haematite is an important factor limiting the material's efficiency. Now, an intermediate of the water-splitting reaction has been identified offering hope that the full mechanism will soon be resolved.

  8. Hispanic American Heritage, Intermediate.

    Science.gov (United States)

    Shepherd, Mike

    This resource book features the cultural heritage of Hispanics living within the United States and includes ideas, materials, and activities to be used with students in the intermediate grades and middle school. This book explores the definition of the term "Hispanic Americans" and suggests a multilayered population with a variety of cultural…

  9. GLOSSARY TO INTERMEDIATE HINDI.

    Science.gov (United States)

    Wisconsin Univ., Madison. Indian Language and Area Center.

    INCLUDED IN THIS GLOSSARY ARE THE VOCABULARY ITEMS FOR THE READINGS IN "INTERMEDIATE HINDI." THE ITEMS ARE ARRANGED BY SELECTION IN SERIAL ORDER. EACH ENTRY INCLUDES NAGARI (DEVANAGARI) SCRIPT SPELLING, A NOTATION OF THE FORM CLASS, AND A SHORT ENGLISH GLOSS. THESE TWO VOLUMES ARE ALSO AVAILABLE AS A SET FOR $7.00 FROM THE COLLEGE PRINTING…

  10. Evaluation of reference genes for real-time quantitative PCR studies in Candida glabrata following azole treatment

    Directory of Open Access Journals (Sweden)

    Li Qingdi

    2012-06-01

    Full Text Available Abstract Background The selection of stable and suitable reference genes for real-time quantitative PCR (RT-qPCR is a crucial prerequisite for reliable gene expression analysis under different experimental conditions. The present study aimed to identify reference genes as internal controls for gene expression studies by RT-qPCR in azole-stimulated Candida glabrata. Results The expression stability of 16 reference genes under fluconazole stress was evaluated using fold change and standard deviation computations with the hkgFinder tool. Our data revealed that the mRNA expression levels of three ribosomal RNAs (RDN5.8, RDN18, and RDN25 remained stable in response to fluconazole, while PGK1, UBC7, and UBC13 mRNAs showed only approximately 2.9-, 3.0-, and 2.5-fold induction by azole, respectively. By contrast, mRNA levels of the other 10 reference genes (ACT1, EF1α, GAPDH, PPIA, RPL2A, RPL10, RPL13A, SDHA, TUB1, and UBC4 were dramatically increased in C. glabrata following antifungal treatment, exhibiting changes ranging from 4.5- to 32.7-fold. We also assessed the expression stability of these reference genes using the 2-ΔΔCT method and three other software packages. The stability rankings of the reference genes by geNorm and the 2-ΔΔCT method were identical to those by hkgFinder, whereas the stability rankings by BestKeeper and NormFinder were notably different. We then validated the suitability of six candidate reference genes (ACT1, PGK1, RDN5.8, RDN18, UBC7, and UBC13 as internal controls for ten target genes in this system using the comparative CT method. Our validation experiments passed for all six reference genes analyzed except RDN18, where the amplification efficiency of RDN18 was different from that of the ten target genes. Finally, we demonstrated that the relative quantification of target gene expression varied according to the endogenous control used, highlighting the importance of the choice of internal controls in such

  11. [The occurrence of Biomphalaria straminea (Pulmonata: Planorbidae) on an aquaculture farm of IBAMA in Uberlândia, MG. Instituto Brasileiro do Meio Ambiente a dos Recursos Naturais Renováveis].

    Science.gov (United States)

    Silveira, E de P; Marçal Júnior, O; Machado, M I

    1997-01-01

    This work evaluates the occurrence of freshwater snails in the IBAMA's fish breeding station in Uberlândia, Minas Gerais State. We verified the presence of Biomphalaria straminea in 39.5% of all breeding tanks. None of the snails were infected by Schistosoma mansoni, but further investigation should be done in the area.

  12. The Intermediate Neutrino Program

    CERN Document Server

    Adams, C; Ankowski, A M; Asaadi, J A; Ashenfelter, J; Axani, S N; Babu, K; Backhouse, C; Band, H R; Barbeau, P S; Barros, N; Bernstein, A; Betancourt, M; Bishai, M; Blucher, E; Bouffard, J; Bowden, N; Brice, S; Bryan, C; Camilleri, L; Cao, J; Carlson, J; Carr, R E; Chatterjee, A; Chen, M; Chen, S; Chiu, M; Church, E D; Collar, J I; Collin, G; Conrad, J M; Convery, M R; Cooper, R L; Cowen, D; Davoudiasl, H; De Gouvea, A; Dean, D J; Deichert, G; Descamps, F; DeYoung, T; Diwan, M V; Djurcic, Z; Dolinski, M J; Dolph, J; Donnelly, B; Dwyer, D A; Dytman, S; Efremenko, Y; Everett, L L; Fava, A; Figueroa-Feliciano, E; Fleming, B; Friedland, A; Fujikawa, B K; Gaisser, T K; Galeazzi, M; Galehouse, D C; Galindo-Uribarri, A; Garvey, G T; Gautam, S; Gilje, K E; Gonzalez-Garcia, M; Goodman, M C; Gordon, H; Gramellini, E; Green, M P; Guglielmi, A; Hackenburg, R W; Hackenburg, A; Halzen, F; Han, K; Hans, S; Harris, D; Heeger, K M; Herman, M; Hill, R; Holin, A; Huber, P; Jaffe, D E; Johnson, R A; Joshi, J; Karagiorgi, G; Kaufman, L J; Kayser, B; Kettell, S H; Kirby, B J; Klein, J R; Kolomensky, Yu G; Kriske, R M; Lane, C E; Langford, T J; Lankford, A; Lau, K; Learned, J G; Ling, J; Link, J M; Lissauer, D; Littenberg, L; Littlejohn, B R; Lockwitz, S; Lokajicek, M; Louis, W C; Luk, K; Lykken, J; Marciano, W J; Maricic, J; Markoff, D M; Caicedo, D A Martinez; Mauger, C; Mavrokoridis, K; McCluskey, E; McKeen, D; McKeown, R; Mills, G; Mocioiu, I; Monreal, B; Mooney, M R; Morfin, J G; Mumm, P; Napolitano, J; Neilson, R; Nelson, J K; Nessi, M; Norcini, D; Nova, F; Nygren, D R; Gann, G D Orebi; Palamara, O; Parsa, Z; Patterson, R; Paul, P; Pocar, A; Qian, X; Raaf, J L; Rameika, R; Ranucci, G; Ray, H; Reyna, D; Rich, G C; Rodrigues, P; Romero, E Romero; Rosero, R; Rountree, S D; Rybolt, B; Sanchez, M C; Santucci, G; Schmitz, D; Scholberg, K; Seckel, D; Shaevitz, M; Shrock, R; Smy, M B; Soderberg, M; Sonzogni, A; Sousa, A B; Spitz, J; John, J M St; Stewart, J; Strait, J B; Sullivan, G; Svoboda, R; Szelc, A M; Tayloe, R; Thomson, M A; Toups, M; Vacheret, A; Vagins, M; Van de Water, R G; Vogelaar, R B; Weber, M; Weng, W; Wetstein, M; White, C; White, B R; Whitehead, L; Whittington, D W; Wilking, M J; Wilson, R J; Wilson, P; Winklehner, D; Winn, D R; Worcester, E; Yang, L; Yeh, M; Yokley, Z W; Yoo, J; Yu, B; Yu, J; Zhang, C

    2015-01-01

    The US neutrino community gathered at the Workshop on the Intermediate Neutrino Program (WINP) at Brookhaven National Laboratory February 4-6, 2015 to explore opportunities in neutrino physics over the next five to ten years. Scientists from particle, astroparticle and nuclear physics participated in the workshop. The workshop examined promising opportunities for neutrino physics in the intermediate term, including possible new small to mid-scale experiments, US contributions to large experiments, upgrades to existing experiments, R&D plans and theory. The workshop was organized into two sets of parallel working group sessions, divided by physics topics and technology. Physics working groups covered topics on Sterile Neutrinos, Neutrino Mixing, Neutrino Interactions, Neutrino Properties and Astrophysical Neutrinos. Technology sessions were organized into Theory, Short-Baseline Accelerator Neutrinos, Reactor Neutrinos, Detector R&D and Source, Cyclotron and Meson Decay at Rest sessions.This report summ...

  13. The Intermediate Neutrino Program

    Energy Technology Data Exchange (ETDEWEB)

    Adams, C.; et al.

    2015-03-23

    The US neutrino community gathered at the Workshop on the Intermediate Neutrino Program (WINP) at Brookhaven National Laboratory February 4-6, 2015 to explore opportunities in neutrino physics over the next five to ten years. Scientists from particle, astroparticle and nuclear physics participated in the workshop. The workshop examined promising opportunities for neutrino physics in the intermediate term, including possible new small to mid-scale experiments, US contributions to large experiments, upgrades to existing experiments, R&D plans and theory. The workshop was organized into two sets of parallel working group sessions, divided by physics topics and technology. Physics working groups covered topics on Sterile Neutrinos, Neutrino Mixing, Neutrino Interactions, Neutrino Properties and Astrophysical Neutrinos. Technology sessions were organized into Theory, Short-Baseline Accelerator Neutrinos, Reactor Neutrinos, Detector R&D and Source, Cyclotron and Meson Decay at Rest sessions.This report summarizes discussion and conclusions from the workshop.

  14. Processing of predicted substrates of fungal Kex2 proteinases from Candida albicans, C. glabrata, Saccharomyces cerevisiae and Pichia pastoris

    Directory of Open Access Journals (Sweden)

    Bader Oliver

    2008-07-01

    Full Text Available Abstract Background Kexin-like proteinases are a subfamily of the subtilisin-like serine proteinases with multiple regulatory functions in eukaryotes. In the yeast Saccharomyces cerevisiae the Kex2 protein is biochemically well investigated, however, with the exception of a few well known proteins such as the α-pheromone precursors, killer toxin precursors and aspartic proteinase propeptides, very few substrates are known. Fungal kex2 deletion mutants display pleiotropic phenotypes that are thought to result from the failure to proteolytically activate such substrates. Results In this study we have aimed at providing an improved assembly of Kex2 target proteins to explain the phenotypes observed in fungal kex2 deletion mutants by in vitro digestion of recombinant substrates from Candida albicans and C. glabrata. We identified CaEce1, CA0365, one member of the Pry protein family and CaOps4-homolog proteins as novel Kex2 substrates. Conclusion Statistical analysis of the cleavage sites revealed extended subsite recognition of negatively charged residues in the P1', P2' and P4' positions, which is also reflected in construction of the respective binding pockets in the ScKex2 enzyme. Additionally, we provide evidence for the existence of structural constrains in potential substrates prohibiting proteolysis. Furthermore, by using purified Kex2 proteinases from S. cerevisiae, P. pastoris, C. albicans and C. glabrata, we show that while the substrate specificity is generally conserved between organisms, the proteinases are still distinct from each other and are likely to have additional unique substrate recognition.

  15. Intermediate energy data

    International Nuclear Information System (INIS)

    Subgroup 13 (SG13) on Intermediate Energy Nuclear data was formed by NEA Nuclear Science Committee to solve common problems of these types of data for nuclear applications. An overview is presented in this final report of the present activities of SG13, including data needs, high-priority nuclear data request list (nuclides), compilation of experimental data, specialists meetings and benchmarks, data formats and data libraries. Some important accomplishments are summarized, and recommendations are presented. (R.P.)

  16. Volatility and Financial Intermediation

    OpenAIRE

    Joshua Aizenman; Andrew Powell

    1997-01-01

    Following the Tequila period, its after-effects in Latin America and recent events in South East Asia, the effect of volatility on emerging market economies has become an important topic of research with the domestic financial intermediation process being advanced as one of the most important transmission mechanisms. At the same time there has been continued interest in issues related to imperfect information and rationing in credit markets. In this paper, we consider an economy where risk ne...

  17. Molecular identification of similar species of the genus Biomphalaria (Mollusca: Planorbidae determined by a polymerase chain reaction-restriction fragment length polymorphism

    Directory of Open Access Journals (Sweden)

    Caldeira Roberta Lima

    1998-01-01

    Full Text Available The freshwater snails Biomphalaria straminea, B. intermedia, B. kuhniana and B. peregrina, are morphologically similar; based on this similarity the first three species were therefore grouped in the complex B. straminea. The morphological identification of these species is based on characters such as vaginal wrinkling, relation between prepuce: penial sheath:deferens vas and number of muscle layers in the penis wall. In this study the polymerase chain reaction restriction fragment length polymorphism technique was used for molecular identification of these molluscs. This technique is based on the amplification of the internal transcribed spacer regions ITS1 e ITS2 of the ribosomal RNA gene and subsequent digestion of these fragments by restriction enzymes. Six enzymes were tested: Dde I, Mnl I, Hae III, Rsa I, Hpa II e Alu I. The restriction patterns obtained with DdeI presented the best profile for separation of the four species of Biomphalaria. The profiles obtained with all the enzymes were used to estimate the genetic distances among the species through analysis of common banding patterns.

  18. Viral Preprotoxin Signal Sequence Allows Efficient Secretion of Green Fluorescent Protein by Candida glabrata, Pichia pastoris, Saccharomyces cerevisiae, and Schizosaccharomyces pombe

    OpenAIRE

    Eiden-Plach, Antje; Zagorc, Tatjana; Heintel, Tanja; Carius, Yvonne; Breinig, Frank; Manfred J Schmitt

    2004-01-01

    Besides its importance as model organism in eukaryotic cell biology, yeast species have also developed into an attractive host for the expression, processing, and secretion of recombinant proteins. Here we investigated foreign protein secretion in four distantly related yeasts (Candida glabrata, Pichia pastoris, Saccharomyces cerevisiae, and Schizosaccharomyces pombe) by using green fluorescent protein (GFP) as a reporter and a viral secretion signal sequence derived from the K28 preprotoxin ...

  19. Effects of Bayluscide WP 70® on the Survival and Water-leaving Behaviour of Biomphalaria straminea, Snail Host of Schistosomiasis in Northeast Brazil

    Directory of Open Access Journals (Sweden)

    Sarquis Otília

    1997-01-01

    Full Text Available The toxic and behavioural effects of niclosamide (Bayluscide WP 70® on Biomphalaria straminea from a highly endemic area of schistosomiasis in northeastern Brazil were investigated through laboratory bioassays. The LD50 and LD90 were 0.114 mg/l and 0.212 mg/l, respectively. Water-leaving behaviour occurred among 14% to 30% of the snails in the presence of sublethal doses of niclosamide and among 16% of the controls. It was concluded that both the relatively low susceptibility to niclosamide and water-leaving behaviour of local B. straminea may be responsible for the recolonization of transmission foci after mollusciciding. It was suggested that recently improved measures of snail control, such as controlled-release formulations of niclosamide and plant molluscicides should be considered in areas where snail control is recommended

  20. Molluscicidal Activity of the Methanol Extract of Callistemon viminalis (Sol. ex Gaertner) G.Don ex Loudon Fruits, Bark and Leaves against Biomphalaria alexandrina Snails

    Science.gov (United States)

    A Gohar, Ahmed; T Maatooq, Galal; R Gadara, Sahar; S Aboelmaaty, Walaa; M El-Shazly, Atef

    2014-01-01

    Methanol extracts of Callistemon viminalis (Sol. Ex Gaertner) G.Don Ex Loudon fruits, bark and leaves were tested for molluscicidal activity. Snails were collected and kept in dechlorinated water under standard condition. Ten adults Biomphalaria Alexandrina, of the same size, were introduced in plastic acquaria for each experiment. The fruits, barks and leaves were extracted with methanol and the methanol extracts were kept for testing as molluscicides. Different extracts proved to have molluscicidal activity against the vector of schistosomiasis, B. alexandrina snails. LC50 values for C. viminalis fruits, bark and leaves were 6.2, 32 and 40 ppm respectively. The C. viminalis fruits extract showed the highest effect against the tested snails. Histopathological studies proved that the site of action of all tested extracts was localized in the digestive system and hermaphrodite gland. PMID:25237345

  1. β-Aescin at subinhibitory concentration (sub-MIC) enhances susceptibility of Candida glabrata clinical isolates to nystatin.

    Science.gov (United States)

    Franiczek, Roman; Gleńsk, Michał; Krzyżanowska, Barbara; Włodarczyk, Maciej

    2015-11-01

    Aescin (escin) derived from the seeds of horse chestnut (Aesculus hippocastanum L.) is a natural mixture of triterpene saponins exhibiting a wide variety of pharmacological properties, including antiinflammatory, analgesic, and antipyretic activities. However, data concerning antifungal activities of these compounds are limited. This study aims to evaluate the in vitro antifungal susceptibility of Candida glabrata clinical isolates to α-aescin sodium, β-aescin crystalline and β-aescin sodium using the disk diffusion (DD) and broth microdilution (BMD) methods. Moreover, the influence of subinhibitory concentration (0.5×MIC) of β-aescins on the nystatin MIC was also studied. In general, the results obtained by the DD assay correlated well with those obtained by the BMD method. Both β-aescins effectively inhibited the growth of all 24 strains tested. The minimum inhibitory concentration (MIC) values ranging from 8 to 32 μg/ml for β-aescin crystalline, whereas those of β-aescin sodium were slightly lower and ranged from 4 to 16 μg/ml. In contrast, α-aescin sodium was found to be completely ineffective against the strains studied. MIC values of nystatin were reduced 2-16-fold and 2-4-fold in the presence of subinhibitory concentration of β-aescin crystalline and β-aescin sodium, respectively. Results of the present study may suggest the additive interaction between β-aescin and nystatin. PMID:26092104

  2. Application of response surface methodology in medium optimization for pyruvic acid production of Torulopsis glabrata TP19 in batch fermentation

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jian; GAO Nian-fa

    2007-01-01

    Response surface methodology (RSM) was used to optimize the fermentation medium for enhancing pyruvic acid production by Torulopsis glabrata TP19. In the first step of optimization, with Plackett-Burman design, ammonium sulfate,glucose and nicotinic acid were found to be the important factors affecting pyruvic acid production significantly. In the second step,a 23 full factorial central composite design and RSM were applied to determine the optimal concentration of each significant variable. A second-order polynomial was determined by the multiple regression analysis of the experimental data. The optimum values for the critical components were obtained as follows: ammonium sulfate 0.7498 (10.75 g/L), glucose 0.9383 (109.38 g/L)and nicotinic acid 0.3633 (7.86 mg/L) with a predicted value of maximum pyruvic acid production of 42.2 g/L. Under the optimal conditions, the practical pyruvic acid production was 42.4 g/L. The determination coefficient (R2) was 0.9483, which ensures adequate credibility of the model. By scaling up fermentation from flask to jar fermentor, we obtained promising results.

  3. Antifungal activity of silver nanoparticles in combination with nystatin and chlorhexidine digluconate against Candida albicans and Candida glabrata biofilms.

    Science.gov (United States)

    Monteiro, Douglas R; Silva, Sónia; Negri, Melyssa; Gorup, Luiz F; de Camargo, Emerson R; Oliveira, Rosário; Barbosa, Debora B; Henriques, Mariana

    2013-11-01

    Although silver nanoparticles (SN) have been investigated as an alternative to conventional antifungal drugs in the control of Candida-associated denture stomatitis, the antifungal activity of SN in combination with antifungal drugs against Candida biofilms remains unknown. Therefore, the aim of this study was to evaluate the antifungal efficacy of SN in combination with nystatin (NYT) or chlorhexidine digluconate (CHG) against Candida albicans and Candida glabrata biofilms. The drugs alone or combined with SN were applied on mature Candida biofilms (48 h), and after 24 h of treatment their antibiofilm activities were assessed by total biomass quantification (by crystal violet staining) and colony forming units enumeration. The structure of Candida biofilms was analysed by scanning electron microscopy (SEM) images. The data indicated that SN combined with either NYT or CHG demonstrated synergistic antibiofilm activity, and this activity was dependent on the species and on the drug concentrations used. SEM images showed that some drug combinations were able to disrupt Candida biofilms. The results of this study suggest that the combination of SN with NYT or CHG may have clinical implications in the treatment of denture stomatitis. However, further studies are needed before recommending the use of these drugs safely in clinical situations. PMID:23773119

  4. Atomic structure of the nuclear pore complex targeting domain of a Nup116 homologue from the yeast, Candida glabrata

    Energy Technology Data Exchange (ETDEWEB)

    Sampathkumar, Parthasarathy; Kim, Seung Joong; Manglicmot, Danalyn; Bain, Kevin T.; Gilmore, Jeremiah; Gheyi, Tarun; Phillips, Jeremy; Pieper, Ursula; Fernandez-Martinez, Javier; Franke, Josef D.; Matsui, Tsutomu; Tsuruta, Hiro; Atwell, Shane; Thompson, Devon A.; Emtage, J. Spencer; Wasserman, Stephen R.; Rout, Michael P.; Sali, Andrej; Sauder, J. Michael; Almo, Steven C.; Burley, Stephen K. (Einstein); (SLAC); (Rockefeller); (UCSF); (Lilly)

    2012-10-23

    The nuclear pore complex (NPC), embedded in the nuclear envelope, is a large, dynamic molecular assembly that facilitates exchange of macromolecules between the nucleus and the cytoplasm. The yeast NPC is an eightfold symmetric annular structure composed of {approx}456 polypeptide chains contributed by {approx}30 distinct proteins termed nucleoporins. Nup116, identified only in fungi, plays a central role in both protein import and mRNA export through the NPC. Nup116 is a modular protein with N-terminal 'FG' repeats containing a Gle2p-binding sequence motif and a NPC targeting domain at its C-terminus. We report the crystal structure of the NPC targeting domain of Candida glabrata Nup116, consisting of residues 882-1034 [CgNup116(882-1034)], at 1.94 {angstrom} resolution. The X-ray structure of CgNup116(882-1034) is consistent with the molecular envelope determined in solution by small-angle X-ray scattering. Structural similarities of CgNup116(882-1034) with homologous domains from Saccharomyces cerevisiae Nup116, S. cerevisiae Nup145N, and human Nup98 are discussed.

  5. Financial Intermediation and Economic Growth

    OpenAIRE

    Dima, Bogdan; Petru-Eugen OPRIȘ

    2013-01-01

    The paper evaluates the relationship between financial intermediation and the economic growth in the developing economic systems. First, using dataset from 28 countries,between 2001 and 2010 we define a financial intermediation indicator applying EFA method. We use several dimensions of the financial intermediation: Domestic credit provided by banking sector (% of GDP); Domestic credit to private sector (% of GDP); Broad money (% of GDP); Market capitalization of listed companies (% of GDP). ...

  6. Financial Intermediation and Macroeconomic Analysis

    OpenAIRE

    Michael Woodford

    2010-01-01

    Understanding phenomena such as the recent financial crisis, and possible policy responses, requires the use of a macroeconomic framework in which financial intermediation matters for the allocation of resources. Neither standard macroeconomic models that abstract from financial intermediation nor traditional models of the "bank lending channel" are adequate as a basis for understanding the recent crisis. Instead we need models in which intermediation plays a crucial role, but in which interm...

  7. Welding. Performance Objectives. Intermediate Course.

    Science.gov (United States)

    Vincent, Kenneth

    Several intermediate performance objectives and corresponding criterion measures are listed for each of nine terminal objectives for an intermediate welding course. The materials were developed for a 36-week (3 hours daily) course designed to prepare the student for employment in the field of welding. Electric welding and specialized (TIG & MIG)…

  8. Recent results on intermediate polars

    OpenAIRE

    Hellier, Coel

    1999-01-01

    I review recent activity in the field of intermediate polars, concentrating on: the mode of accretion (disc-fed, disc-overflow or discless); accretion curtains (the transition region and the accretion footprint); X-ray pulse profiles (occultation and absorption effects); accretion columns (mass determinations, line-broadening, the soft X-ray component), and outbursts in intermediate polars.

  9. Optimal Auditing Under Intermediated Contracting

    OpenAIRE

    Wolfgang Gick

    2004-01-01

    This paper builds on Faure-Grimaud and Martimort’s [Economics Letters 71 (2001) 75-82] analysis of intermediated contracting. I argue that intermediated contracting permits one form of auditing, in which the sub-contract offered to the firm is examined, contingent on the intermediary’s report. Auditing reduces the intermediary’s rent and increases allocative efficiency.

  10. Determination of quercetin, plumbagin and total flavonoids in Drosera peltata Smith var. glabrata Y.Z.Ruan

    Directory of Open Access Journals (Sweden)

    Yu He

    2012-01-01

    Full Text Available Background: Drosera peltata Smith var. glabrata Y.Z.Ruan, a kind of wild carnivorous plants in the family Droseraceae, has been used for the treatment of rheumatism and bruises in Chinese folk. None of compounds in this herb has been quantified in the previous studies. Objective: To develop a validated and reliable HPLC method for the simultaneous determination of two bioactive constituents - quercetin and plumbagin, and establish a simple UV spectrophotometry method for the analysis of total flavonoids content. Materials and Methods: Chromatographic separation was performed by using a HPLC system consisting of an Agilent Eclipse XDB C 18 column and a gradient elution system of acetonitrile and water (containing 0.1% phosphoric acid, V/V within 20 minutes. Comparing with quercetin complex with Al(NO 3 3 , the total flavonoids were determined by UV spectrophotometry at 269 nm. Results: Both methods were validated for linearity (r 2≥0.9994 for quercetin and plumbagin in the HPLC method, r 2 =0.9994 for quercetin in the UV spectrophotometry method, precision (The within-day and between-day variability was less than 0.738% and 1.64% for quercetin and plumbagin in the HPLC method, and was less than 1.67% for quercetin in the UV spectrophotometry method. and recovery (The recoveries of the HPLC method were 96.7-100.4% and 97.4-100.4% for quercetin and plumbagin, respectively, and the recovery of the UV spectrophotometry method was 96.7-99.6% for quercetin. Conclusion: The proposed methods are simple and accurate, and could be practiced to rapidly determine quercetin, plumbagin and total flavonoids in the herbal drug, which provide effective approaches for quality control.

  11. Acute extrarenal kidney damage in the course of infection with fungal strain of Candida glabrata in a patient with type 2 diabetes

    International Nuclear Information System (INIS)

    Background: Acute renal injury is becoming a significant epidemiological problem among patients requiring hospital treatment. Extrarenal aetiology of the kidney injury is recognized in 5 % to 10 % of hospitalized patients; however, the identification of the mycelium of the Candida glabrata as the direct factor causing the acute urinary obstruction is extremely rare. Case Report: A 64-year-old woman was admitted to the clinic because of progressing weakness, nausea and vomiting, poor appetite and reduced urination. On admission, laboratory findings revealed pyuria, inflammatory changes, acute renal failure (eGFR-MDRD 6 ml/min), and hyperglycemia. The patient underwent USG of the abdominal cavity, which showed bilateral hydronephrosis, with lithiasis on the right site. Cystoscopy done the next day revealed that the mucous membrane of the bladder was reddened and had a white coating. During the next several days, a renal fistula was created on the left and right sides. Candida glabrata was isolated from urine, and was sensitive only to voriconazole. V-fend (voriconazole) treatment resulted in increase of diuresis and decrease in creatinine and urea levels. Conclusions: Urinary tract infection caused by Candida glabrata causes significant therapeutic problems. In most cases, these yeasts are resistant to triazole anti-fungal drugs such as fluconazole, which translates into significantly increased mortality of patients. To date, a similar case was described only by one group of doctors, however, due to the intensity of the currently used immunosuppression and multiantibiotic therapy, increased incidence of diabetes and the aging of the population, it is expected that the prevalence of this clinical problem will increase. (authors)

  12. The dual role of candida glabrata drug:H+ antiporter CgAqr1 (ORF CAGL0J09944g) in antifungal drug and acetic acid resistance.

    Science.gov (United States)

    Costa, Catarina; Henriques, André; Pires, Carla; Nunes, Joana; Ohno, Michiyo; Chibana, Hiroji; Sá-Correia, Isabel; Teixeira, Miguel C

    2013-01-01

    Opportunistic Candida species often have to cope with inhibitory concentrations of acetic acid, in the acidic environment of the vaginal mucosa. Given that the ability of these yeast species to tolerate stress induced by weak acids and antifungal drugs appears to be a key factor in their persistence and virulence, it is crucial to understand the underlying mechanisms. In this study, the drug:H(+) antiporter CgAqr1 (ORF CAGL0J09944g), from Candida glabrata, was identified as a determinant of resistance to acetic acid, and also to the antifungal agents flucytosine and, less significantly, clotrimazole. These antifungals were found to act synergistically with acetic acid against this pathogen. The action of CgAqr1 in this phenomenon was analyzed. Using a green fluorescent protein fusion, CgAqr1 was found to localize to the plasma membrane and to membrane vesicles when expressed in C. glabrata or, heterologously, in Saccharomyces cerevisiae. Given its ability to complement the susceptibility phenotype of its S. cerevisiae homolog, ScAqr1, CgAqr1 was proposed to play a similar role in mediating the extrusion of chemical compounds. Significantly, the expression of this gene was found to reduce the intracellular accumulation of (3)H-flucytosine and, to a moderate extent, of (3)H-clotrimazole, consistent with a direct role in antifungal drug efflux. Interestingly, no effect of CgAQR1 deletion could be found on the intracellular accumulation of (14)C-acetic acid, suggesting that its role in acetic acid resistance may be indirect, presumably through the transport of a still unidentified physiological substrate. Although neither of the tested chemicals induces changes in CgAQR1 expression, pre-exposure to flucytosine or clotrimazole was found to make C. glabrata cells more sensitive to acetic acid stress. Results from this study show that CgAqr1 is an antifungal drug resistance determinant and raise the hypothesis that it may play a role in C. glabrata persistent colonization

  13. The dual role of Candida glabrata Drug:H+ Antiporter CgAqr1 (ORF CAGL0J09944g in antifungal drug and acetic acid resistance

    Directory of Open Access Journals (Sweden)

    Catarina eCosta

    2013-06-01

    Full Text Available Opportunistic Candida species often have to cope with inhibitory concentrations of acetic acid, in the acidic environment of the vaginal mucosa. Given that the ability of these yeast species to tolerate stress induced by weak acids and antifungal drugs appears to be a key factor in their persistence and virulence, it is crucial to understand the underlying mechanisms.In this study, the Drug:H+ Antiporter CgAqr1 (ORF CAGL0J09944g, from Candida glabrata, was identified as a determinant of resistance to acetic acid, and also to the antifungal agents flucytosine and, less significantly, clotrimazole. These antifungals were found to act synergistically with acetic acid against this pathogen. The action of CgAqr1 in this phenomenon was analyzed. Using a GFP fusion, CgAqr1 was found to localize to the plasma membrane and to membrane vesicles when expressed in C. glabrata or, heterologously, in Saccharomyces cerevisiae. Given its ability to complement the susceptibility phenotype of its S. cerevisiae homolog, ScAqr1, CgAqr1 was proposed to play a similar role in mediating the extrusion of chemical compounds. Significantly, the expression of this gene was found to reduce the intracellular accumulation of 3H-flucytosine and, to a moderate extent, of 3H-clotrimazole, consistent with a direct role in antifungal drug efflux. Interestingly, no effect of CgAQR1 deletion could be found on the intracellular accumulation of 14C-acetic acid, suggesting that its role in acetic acid resistance may be indirect, presumably through the transport of a still unidentified physiological substrate. Although neither of the tested chemicals induces changes in CgAQR1 expression, pre-exposure to flucytosine or clotrimazole was found to make C. glabrata cells more sensitive to acetic acid stress. Results from this study show that CgAqr1 is an antifungal drug resistance determinant and raise the hypothesis that it may play a role in C. glabrata persistent colonization and

  14. Composição e sazonalidade dos moluscos do alto rio Paraná, Brasil, e sua potencialidade como hospedeiros intermediários de digenéticos - DOI: 10.4025/actascibiolsci.v30i3.5018 Composition and seasonality of mollusks from the upper Paraná river, Brazil, and their potentiality as intermediate hosts for digeneans - DOI: 10.4025/actascibiolsci.v30i3.5018

    Directory of Open Access Journals (Sweden)

    Gilberto Cezar Pavanelli

    2008-10-01

    Full Text Available Este trabalho analisa a composição e a sazonalidade das espécies de moluscos potenciais hospedeiros intermediários de trematódeos digenéticos, bem como fornece informações a respeito das possíveis infecções por diplostomídeos nesta comunidade, em ambientes lênticos da planície de inundação do alto rio Paraná. Foram coletadas e analisadas dez espécies de moluscos, e houve nítida sazonalidade na densidade e abundância dos moluscos, correlacionada significativamente com a temperatura da água. Os maiores valores observados foram entre os meses de novembro de 2002 a fevereiro de 2003. Apenas Biomphalaria peregrina caracterizou-se como hospedeiro para Diplostomidae, pois nesta espécie foram encontradas 32 cercárias de Hysteromorpha triloba em março de 2003.This study analyzes the composition and seasonality of mollusk species as potential intermediate hosts for digenean trematodes, and also supplies information regarding the possible infections by diplostomidae in that community, in lentic environments of the upper Paraná river floodplain. Ten species of mollusks were collected and analyzed, with noticeable seasonality in the density and abundance of mollusks, significantly correlated with water temperature. The highest values observed were in the period between November 2002 and February 2003. Only Biomphalaria peregrina was characterized as a host for diplostomidae, given that 32 cercariae of Hysteromorpha triloba were found in this species in March 2003.

  15. Intermediation Costs and Financial Fragility

    OpenAIRE

    Kaplan, Cafer; Salman, Ferhan

    2007-01-01

    This paper studies implications of intermediation costs in credit markets. The presence of intermediation costs increases the amount of risky projects therefore results in financial fragility. Moreover, for an open economy that has a perfectly liberal capital account, prudent firms finance their projects from foreign markets therefore shrinking the domestic credit markets. The theoretical predictions of our model gains support by Turkish data for the 1991 – 2004 period. Data suggests that an ...

  16. Wealth, Financial Intermediation and Growth

    OpenAIRE

    Gaytan, Alejandro; Ranci??re, Romain

    2005-01-01

    This paper presents empirical support for the existence of wealth effects in the contribution of financial intermediation to economic growth, and offers a theoretical explanation for these effects. Using GMM dynamic panel data techniques applied to study the growth-promoting effects of financial intermediation, we show that the exogenous contribution of financial development on economic growth has different effects for different levels of income per capita. We find that this contribution is g...

  17. Hydrology and density feedbacks control the ecology of intermediate hosts of schistosomiasis across habitats in seasonal climates.

    Science.gov (United States)

    Perez-Saez, Javier; Mande, Theophile; Ceperley, Natalie; Bertuzzo, Enrico; Mari, Lorenzo; Gatto, Marino; Rinaldo, Andrea

    2016-06-01

    We report about field and theoretical studies on the ecology of the aquatic snails (Bulinus spp. and Biomphalaria pfeifferi) that serve as obligate intermediate hosts in the complex life cycle of the parasites causing human schistosomiasis. Snail abundance fosters disease transmission, and thus the dynamics of snail populations are critically important for schistosomiasis modeling and control. Here, we single out hydrological drivers and density dependence (or lack of it) of ecological growth rates of local snail populations by contrasting novel ecological and environmental data with various models of host demography. Specifically, we study various natural and man-made habitats across Burkina Faso's highly seasonal climatic zones. Demographic models are ranked through formal model comparison and structural risk minimization. The latter allows us to evaluate the suitability of population models while clarifying the relevant covariates that explain empirical observations of snail abundance under the actual climatic forcings experienced by the various field sites. Our results link quantitatively hydrological drivers to distinct population dynamics through specific density feedbacks, and show that statistical methods based on model averaging provide reliable snail abundance projections. The consistency of our ranking results suggests the use of ad hoc models of snail demography depending on habitat type (e.g., natural vs. man-made) and hydrological characteristics (e.g., ephemeral vs. permanent). Implications for risk mapping and space-time allocation of control measures in schistosomiasis-endemic contexts are discussed. PMID:27162339

  18. Hydrology and density feedbacks control the ecology of intermediate hosts of schistosomiasis across habitats in seasonal climates.

    Science.gov (United States)

    Perez-Saez, Javier; Mande, Theophile; Ceperley, Natalie; Bertuzzo, Enrico; Mari, Lorenzo; Gatto, Marino; Rinaldo, Andrea

    2016-06-01

    We report about field and theoretical studies on the ecology of the aquatic snails (Bulinus spp. and Biomphalaria pfeifferi) that serve as obligate intermediate hosts in the complex life cycle of the parasites causing human schistosomiasis. Snail abundance fosters disease transmission, and thus the dynamics of snail populations are critically important for schistosomiasis modeling and control. Here, we single out hydrological drivers and density dependence (or lack of it) of ecological growth rates of local snail populations by contrasting novel ecological and environmental data with various models of host demography. Specifically, we study various natural and man-made habitats across Burkina Faso's highly seasonal climatic zones. Demographic models are ranked through formal model comparison and structural risk minimization. The latter allows us to evaluate the suitability of population models while clarifying the relevant covariates that explain empirical observations of snail abundance under the actual climatic forcings experienced by the various field sites. Our results link quantitatively hydrological drivers to distinct population dynamics through specific density feedbacks, and show that statistical methods based on model averaging provide reliable snail abundance projections. The consistency of our ranking results suggests the use of ad hoc models of snail demography depending on habitat type (e.g., natural vs. man-made) and hydrological characteristics (e.g., ephemeral vs. permanent). Implications for risk mapping and space-time allocation of control measures in schistosomiasis-endemic contexts are discussed.

  19. Intermediate ions in the atmosphere

    Science.gov (United States)

    Tammet, Hannes; Komsaare, Kaupo; Hõrrak, Urmas

    2014-01-01

    Intermediate air ions are charged nanometer-sized aerosol particles with an electric mobility of about 0.03-0.5 cm2 V- 1 s- 1 and a diameter of about 1.5-7.5 nm. Intensive studies of new particle formation provided good knowledge about intermediate ions during burst events of atmospheric aerosol nucleation. Information about intermediate ions during quiet periods between the bursts remained poor. The new mobility analyzer SIGMA can detect air ions at concentrations of mobility fractions of about 1 cm- 3 and enables studying intermediate ions during quiet periods. It became evident that intermediate ions always exist in atmospheric air and should be considered an indicator and a mediator of aerosol nucleation. The annual average concentration of intermediate ions of one polarity in Tartu, Estonia, was about 40 cm- 3 while 5% of the measurements showed a concentration of less than 10 cm- 3. The fraction concentrations in logarithmic 1/8-decade mobility bins between 0.1 and 0.4 cm2 V- 1 s- 1 often dropped below 1 cm- 3. The bursts of intermediate ions at stations separated by around 100 km appeared to be correlated. The lifespan of intermediate ions in the atmosphere is a few minutes, and they cannot be carried by wind over long distances. Thus the observed long-range correlation of intermediate ions is explained by simultaneous changes in air composition in widely spaced stations. A certain amount of intermediate ion bursts, predominantly of negative polarity, are produced by the balloelectric effect at the splashing of water drops during rain. These bursts are usually excluded when speaking about new particle formation because the balloelectric particles are assumed not to grow to the size of the Aitken mode. The mobility distribution of balloelectric ions is uniform in shape in all measurements. The maximum is located at a mobility of about 0.2 cm2 V- 1 s- 1, which corresponds to the diameter of particles of about 2.5 nm.

  20. Estudo dos dados obtidos de uma população de Biomphalaria glabrata de Belo Horizonte infectada por schistosoma mansoni da mesma cidade, e de uma população de B. tenagophila de Campinas. infectada por S. mansoni de São José dos Campos

    Directory of Open Access Journals (Sweden)

    Luiz A. Magalhães

    1969-01-01

    Full Text Available O autor estuda os dados obtidos pela infecção de moluscos de Campinas e de Belo Horizonte por miracídios de S. mansoni. Chega à conclusão de que a população de Belo Horizonte mostrou-se mais susceptível à infecção pelo helminto do que a população de moluscos Campinas.

  1. The Candida genome database incorporates multiple Candida species: multispecies search and analysis tools with curated gene and protein information for Candida albicans and Candida glabrata.

    Science.gov (United States)

    Inglis, Diane O; Arnaud, Martha B; Binkley, Jonathan; Shah, Prachi; Skrzypek, Marek S; Wymore, Farrell; Binkley, Gail; Miyasato, Stuart R; Simison, Matt; Sherlock, Gavin

    2012-01-01

    The Candida Genome Database (CGD, http://www.candidagenome.org/) is an internet-based resource that provides centralized access to genomic sequence data and manually curated functional information about genes and proteins of the fungal pathogen Candida albicans and other Candida species. As the scope of Candida research, and the number of sequenced strains and related species, has grown in recent years, the need for expanded genomic resources has also grown. To answer this need, CGD has expanded beyond storing data solely for C. albicans, now integrating data from multiple species. Herein we describe the incorporation of this multispecies information, which includes curated gene information and the reference sequence for C. glabrata, as well as orthology relationships that interconnect Locus Summary pages, allowing easy navigation between genes of C. albicans and C. glabrata. These orthology relationships are also used to predict GO annotations of their products. We have also added protein information pages that display domains, structural information and physicochemical properties; bibliographic pages highlighting important topic areas in Candida biology; and a laboratory strain lineage page that describes the lineage of commonly used laboratory strains. All of these data are freely available at http://www.candidagenome.org/. We welcome feedback from the research community at candida-curator@lists.stanford.edu.

  2. Laboratory evaluation of B-2 as a molluscicide in the control of the snail intermediate hosts of schistosomiasis in South Africa.

    Science.gov (United States)

    Joubert, P H; Pretorius, S J

    1991-08-01

    There is a continuous need for the development and evaluation of new, inexpensive but highly effective molluscides for the control of freshwater snails acting as intermediate hosts of schistomiasis. For this reason B-2 (Hokko Chemical Industry Co. Ltd, Japan), also called Phebrol (sodium 2,5-dichloro-4-bromophenol), was evaluated in our laboratory as a candidate molluscicide for the control of freshwater snails in South Africa. Bulinus africanus and Biomphalaria pfeifferi, intermediate hosts of Schistosoma haematobium and Schistosoma mansoni respectively, were exposed to different B-2 concentrations for 24 and 48 hours. An indigenous fish species, Oreochromis mossambicus, which is common in local schistosomiasis endemic areas, was also exposed to the molluscicide. The calculated values obtained from a probit analysis (LC50, 24 hours: B. africanus = 2.6 mg 1(-1) and B. pfeifferi = 2.9 mg 1(-1), indicated that these species from southern Africa are less sensitive to B-2 than are B. truncatus and B. pfeifferi from northern Africa, which in turn are less sensitive than the Oncomelania spp. from Japan, China and the Philippines. It is expected that molluscicidal levels of B-2 would be harmful to O. mossambicus populations. Although B-2 has a marked potential for snail control in South Africa, niclosamide (Bayluscide) remains the molluscicide of choice. PMID:1796888

  3. Differentiation of Candida glabrata, C. nivariensis and C. bracarensis based on fragment length polymorphism of ITS1 and ITS2 and restriction fragment length polymorphism of ITS and D1/D2 regions in rDNA

    DEFF Research Database (Denmark)

    Mirhendi, H; Bruun, B; Schønheyder, H C;

    2011-01-01

    Different molecular methods for the discrimination of Candida glabrata, C. bracarensis and C. nivariensis were evaluated and the prevalence of these species among Danish blood isolates investigated. Control strains were used to determine fragment length polymorphism in the ITS1, ITS2, ITS1-5.8S...

  4. Rapid detection and identification of Candida albicans and Torulopsis (Candida) glabrata in clinical specimens by species-specific nested PCR amplification of a cytochrome P-450 lanosterol-alpha-demethylase (L1A1) gene fragment.

    Science.gov (United States)

    Burgener-Kairuz, P; Zuber, J P; Jaunin, P; Buchman, T G; Bille, J; Rossier, M

    1994-08-01

    PCR of a Candida albicans cytochrome P-450 lanosterol-alpha-demethylase (P450-L1A1) gene segment is a rapid and sensitive method of detection in clinical specimens. This enzyme is a target for azole antifungal action. In order to directly detect and identify the clinically most important species of Candida, we cloned and sequenced 1.3-kbp fragments of the cytochrome P450-L1A1 genes from Torulopsis (Candida) glabrata and from Candida krusei. These segments were compared with the published sequences from C. albicans and Candida tropicalis. Amplimers for gene sequences highly conserved throughout the fungal kingdom were first used; positive PCR results were obtained for C. albicans, T. glabrata, C. krusei, Candida parapsilosis, C. tropicalis, Cryptococcus neoformans, and Trichosporon beigelii DNA extracts. Primers were then selected for a highly variable region of the gene, allowing the species-specific detection from purified DNA of C. albicans, T. glabrata, C. krusei, and C. tropicalis. The assay sensitivity as tested for C. albicans in seeded clinical specimens such as blood, peritoneal fluid, or urine was 10 to 20 cells per 0.1 ml. Compared with results obtained by culture, the sensitivity, specificity, and efficiency of the species-specific nested PCR tested with 80 clinical specimens were 71, 95, and 83% for C. albicans and 100, 97, and 98% for T. glabrata, respectively.

  5. Facultative Sterol Uptake in an Ergosterol-Deficient Clinical Isolate of Candida glabrata Harboring a Missense Mutation in ERG11 and Exhibiting Cross-Resistance to Azoles and Amphotericin B

    NARCIS (Netherlands)

    Hull, Claire M.; Parker, Josie E.; Bader, Oliver; Weig, Michael; Gross, Uwe; Warrilow, Andrew G. S.; Kelly, Diane E.; Kelly, Steven L.

    2012-01-01

    We identified a clinical isolate of Candida glabrata (CG156) exhibiting flocculent growth and cross-resistance to fluconazole (FLC), voriconazole (VRC), and amphotericin B (AMB), with MICs of >256, >256, and 32 mu g ml(-1), respectively. Sterol analysis using gas chromatography-mass spectrometry (GC

  6. Intermediality and the Child Performer

    Science.gov (United States)

    Budd, Natasha

    2016-01-01

    This report details examples of praxis in the creation and presentation of "Joy Fear and Poetry": an intermedial theatre performance in which children aged 7-12 years generated aesthetic gestures using a range of new media forms. The impetus for the work's development was a desire to make an intervention into habituated patterns of…

  7. Cestina pro Pokrocile (Intermediate Czech).

    Science.gov (United States)

    Kabat, Grazyna; And Others

    The textbook in intermediate Czech is designed for second-year students of the language and those who already have a basic knowledge of Czech grammar and vocabulary. It is appropriate for use in a traditional college language classroom, the business community, or a government language school. It can be covered in a year-long conventional…

  8. Material Voices: Intermediality and Autism

    Science.gov (United States)

    Trimingham, Melissa; Shaughnessy, Nicola

    2016-01-01

    Autism continues to be regarded enigmatically; a community that is difficult to access due to perceived disruptions of interpersonal connectedness. Through detailed observations of two children participating in the Arts and Humanities Research Council funded project "Imagining Autism: Drama, Performance and Intermediality as Interventions for…

  9. Larval helminths in intermediate hosts

    DEFF Research Database (Denmark)

    Fredensborg, Brian Lund; Poulin, R

    2005-01-01

    Density-dependent effects on parasite fitness have been documented from adult helminths in their definitive hosts. There have, however, been no studies on the cost of sharing an intermediate host with other parasites in terms of reduced adult parasite fecundity. Even if larval parasites suffer a ...

  10. Authentic Video in Intermediate German.

    Science.gov (United States)

    Lutcavage, Charles

    1992-01-01

    Assorted techniques are offered for introducing authentic German video into the intermediate language curriculum. Television commercials, weather forecasts, and news programs are described as tools for enhancing listening comprehension and expanding students' cultural awareness. Various preparatory activities and follow-up assignments are…

  11. Overcoming the heterologous bias: An in vivo functional analysis of multidrug efflux transporter, CgCdr1p in matched pair clinical isolates of Candida glabrata

    Energy Technology Data Exchange (ETDEWEB)

    Puri, Nidhi; Manoharlal, Raman; Sharma, Monika [Membrane Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067 (India); Sanglard, Dominique [Institut de Microbiologie, Centre Hospitalier Universitaire Vaudois, 1011 Lausanne (Switzerland); Prasad, Rajendra, E-mail: rp47jnu@gmail.com [Membrane Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067 (India)

    2011-01-07

    Research highlights: {yields} First report to demonstrate an in vivo expression system of an ABC multidrug transporter CgCdr1p of C. glabrata. {yields} First report on the structure and functional characterization of CgCdr1p. {yields} Functional conservation of divergent but typical residues of CgCdr1p. {yields} CgCdr1p elicits promiscuity towards substrates and has a large drug binding pocket with overlapping specificities. -- Abstract: We have taken advantage of the natural milieu of matched pair of azole sensitive (AS) and azole resistant (AR) clinical isolates of Candida glabrata for expressing its major ABC multidrug transporter, CgCdr1p for structure and functional analysis. This was accomplished by tagging a green fluorescent protein (GFP) downstream of ORF of CgCDR1 and integrating the resultant fusion protein at its native chromosomal locus in AS and AR backgrounds. The characterization confirmed that in comparison to AS isolate, CgCdr1p-GFP was over-expressed in AR isolates due to its hyperactive native promoter and the GFP tag did not affect its functionality in either construct. We observed that in addition to Rhodamine 6 G (R6G) and Fluconazole (FLC), a recently identified fluorescent substrate of multidrug transporters Nile Red (NR) could also be expelled by CgCdr1p. Competition assays with these substrates revealed the presence of overlapping multiple drug binding sites in CgCdr1p. Point mutations employing site directed mutagenesis confirmed that the role played by unique amino acid residues critical to ATP catalysis and localization of ABC drug transporter proteins are well conserved in C. glabrata as in other yeasts. This study demonstrates a first in vivo novel system where over-expression of GFP tagged MDR transporter protein can be driven by its own hyperactive promoter of AR isolates. Taken together, this in vivo system can be exploited for the structure and functional analysis of CgCdr1p and similar proteins wherein the arte-factual concerns

  12. Essential Oils, Silver Nanoparticles and Propolis as Alternative Agents Against Fluconazole Resistant Candida albicans, Candida glabrata and Candida krusei Clinical Isolates.

    Science.gov (United States)

    Szweda, Piotr; Gucwa, Katarzyna; Kurzyk, Ewelina; Romanowska, Ewa; Dzierżanowska-Fangrat, Katarzyna; Zielińska Jurek, Anna; Kuś, Piotr Marek; Milewski, Sławomir

    2015-06-01

    Development of effective and safe therapeutic treatment of fungal infections remains one of the major challenge for modern medicine. The aim of presented investigation was to analyze the in vitro antifungal activity of selected essential oils, ethanolic extracts of propolis and silver nanoparticles dropped on TiO2 against azole-resistant C. albicans (n = 20), C. glabrata (n = 14) and C. krusei (n = 10) clinical isolates. Among tested essential oils, the highest activity has definitely been found in the case of the oil isolated from the bark of Cinnamomum cassia, with MIC and MFC values for all tested strains in the range of 0.0006-0.0097 % (v/v) and 0.0012-0.019 % (v/v), respectively. High activity was also observed for the Lemon, Basil, Thyme, Geranium and Clove (from buds) essential oils. Significant differences in fungicidal activity have been observed in the case of four tested propolis samples. Only one of them revealed high activity, with MFC values in the range from 0.156 to 1.25 % (v/v). Satisfactory fungicidal activity, against C. albicans and C. glabrata isolates, was also observed in the case of silver nanoparticles, however C. krusei isolates were mostly resistant. We also revealed that constituents of most of essential oils and propolis as well as silver nanoparticles are not substrates for drug transporters, which belong to the most important factors affecting resistance of Candida spp. clinical isolates to many of conventional antimycotics. To conclude, the results of our investigation revealed that essential oils, propolis and silver nanoparticles represent high potential for controlling and prevention candidiasis. PMID:25805904

  13. Financial Intermediation with Risk Aversion

    OpenAIRE

    Hellwig, Martin

    1998-01-01

    The paper extends Diamond's (1984) analysis of financial intermediation to allow for risk aversion of the intermediary. It shows that, as in the case of risk neutrality, the agency costs of external funds provided to an intermediary are relatively small if the intermediary is financing many entrepreneurs with stochastically independent returns. Even though the intermediary is adding rather than subdividing risks, the underlying large-numbers argument is not invalidated by the presence of risk...

  14. Alterations in the fatty acid profile, antioxidant enzymes and protein pattern of Biomphalaria alexandrina snails exposed to the pesticides diazinon and profenfos.

    Science.gov (United States)

    Bakry, Fayez A; El-Hommossany, Karem; Abd El-Atti, Mahmoud; Ismail, Somaya M

    2016-04-01

    The use of pesticides is widespread in agricultural activities. These pesticides may contaminate the irrigation and drainage systems during agriculture activities and pests' control and then negatively affect the biotic and a biotic component of the polluted water courses. The present study aimed to evaluate the effect of the pesticides diazinon and profenfos on some biological activities of Biomphalaria alexandrina snails such as fatty acid profile, some antioxidant enzymes (thioredoxin reductase (TrxR), sorbitol dehydrogenase (SDH), superoxide dismutase (SOD), catalase (CAT) as well as glutathione reductase (GR) and lipid peroxidation (LP)) and protein patterns in snails' tissues exposed for 4 weeks to LC10 of diazinon and profenfos. The results showed that the two pesticides caused considerable reduction in survival rates and egg production of treated snails. Identification of fatty acid composition in snail tissues treated with diazinon and profenfos pesticides was carried out using gas-liquid chromatography (GLC). The results declared alteration in fatty acid profile, fluctuation in percentage of long chain and short chain fatty acid contributions either saturated or unsaturated ones, and a decrease in total lipid content in tissues of snails treated with these pesticides. The data demonstrate that there was a significant inhibition in the activities of tissues SOD, CAT, glutathione reductase (GR), TrxR, and SDH in tissues of treated snails, while a significant elevation was detected in LP as compared to the normal control. On the other hand, the electrophoretic pattern of total protein showed differences in number and molecular weights of protein bands due to the treatment of snails. It was concluded that the residues of diazinon and profenfos pesticides in aquatic environments have toxic effects onB. alexandrina snails. PMID:24215063

  15. Alterations in the fatty acid profile, antioxidant enzymes and protein pattern of Biomphalaria alexandrina snails exposed to the pesticides diazinon and profenfos.

    Science.gov (United States)

    Bakry, Fayez A; El-Hommossany, Karem; Abd El-Atti, Mahmoud; Ismail, Somaya M

    2016-04-01

    The use of pesticides is widespread in agricultural activities. These pesticides may contaminate the irrigation and drainage systems during agriculture activities and pests' control and then negatively affect the biotic and a biotic component of the polluted water courses. The present study aimed to evaluate the effect of the pesticides diazinon and profenfos on some biological activities of Biomphalaria alexandrina snails such as fatty acid profile, some antioxidant enzymes (thioredoxin reductase (TrxR), sorbitol dehydrogenase (SDH), superoxide dismutase (SOD), catalase (CAT) as well as glutathione reductase (GR) and lipid peroxidation (LP)) and protein patterns in snails' tissues exposed for 4 weeks to LC10 of diazinon and profenfos. The results showed that the two pesticides caused considerable reduction in survival rates and egg production of treated snails. Identification of fatty acid composition in snail tissues treated with diazinon and profenfos pesticides was carried out using gas-liquid chromatography (GLC). The results declared alteration in fatty acid profile, fluctuation in percentage of long chain and short chain fatty acid contributions either saturated or unsaturated ones, and a decrease in total lipid content in tissues of snails treated with these pesticides. The data demonstrate that there was a significant inhibition in the activities of tissues SOD, CAT, glutathione reductase (GR), TrxR, and SDH in tissues of treated snails, while a significant elevation was detected in LP as compared to the normal control. On the other hand, the electrophoretic pattern of total protein showed differences in number and molecular weights of protein bands due to the treatment of snails. It was concluded that the residues of diazinon and profenfos pesticides in aquatic environments have toxic effects onB. alexandrina snails.

  16. Branching of keratin intermediate filaments.

    Science.gov (United States)

    Nafeey, Soufi; Martin, Ines; Felder, Tatiana; Walther, Paul; Felder, Edward

    2016-06-01

    Keratin intermediate filaments (IFs) are crucial to maintain mechanical stability in epithelial cells. Since little is known about the network architecture that provides this stiffness and especially about branching properties of filaments, we addressed this question with different electron microscopic (EM) methods. Using EM tomography of high pressure frozen keratinocytes, we investigated the course of several filaments in a branching of a filament bundle. Moreover we found several putative bifurcations in individual filaments. To verify our observation we also visualized the keratin network in detergent extracted keratinocytes with scanning EM. Here bifurcations of individual filaments could unambiguously be identified additionally to bundle branchings. Interestingly, identical filament bifurcations were also found in purified keratin 8/18 filaments expressed in Escherichia coli which were reassembled in vitro. This excludes that an accessory protein contributes to the branch formation. Measurements of the filament cross sectional areas showed various ratios between the three bifurcation arms. This demonstrates that intermediate filament furcation is very different from actin furcation where an entire new filament is attached to an existing filament. Instead, the architecture of intermediate filament bifurcations is less predetermined and hence consistent with the general concept of IF formation. PMID:27039023

  17. Role of Intermediate Filaments in Vesicular Traffic

    Directory of Open Access Journals (Sweden)

    Azzurra Margiotta

    2016-04-01

    Full Text Available Intermediate filaments are an important component of the cellular cytoskeleton. The first established role attributed to intermediate filaments was the mechanical support to cells. However, it is now clear that intermediate filaments have many different roles affecting a variety of other biological functions, such as the organization of microtubules and microfilaments, the regulation of nuclear structure and activity, the control of cell cycle and the regulation of signal transduction pathways. Furthermore, a number of intermediate filament proteins have been involved in the acquisition of tumorigenic properties. Over the last years, a strong involvement of intermediate filament proteins in the regulation of several aspects of intracellular trafficking has strongly emerged. Here, we review the functions of intermediate filaments proteins focusing mainly on the recent knowledge gained from the discovery that intermediate filaments associate with key proteins of the vesicular membrane transport machinery. In particular, we analyze the current understanding of the contribution of intermediate filaments to the endocytic pathway.

  18. Intermedial Strategies of Memory in Contemporary Novels

    DEFF Research Database (Denmark)

    Tanderup, Sara

    2014-01-01

    In her article "Intermedial Strategies and Memory in Contemporary Novels" Sara Tanderup discusses a tendency in contemporary literature towards combining intermedial experiments with a thematic preoccupation with memory and trauma. Analyzing selected works by Steven Hall, Jonathan Safran Foer...

  19. Role of Intermediate Filaments in Vesicular Traffic.

    Science.gov (United States)

    Margiotta, Azzurra; Bucci, Cecilia

    2016-01-01

    Intermediate filaments are an important component of the cellular cytoskeleton. The first established role attributed to intermediate filaments was the mechanical support to cells. However, it is now clear that intermediate filaments have many different roles affecting a variety of other biological functions, such as the organization of microtubules and microfilaments, the regulation of nuclear structure and activity, the control of cell cycle and the regulation of signal transduction pathways. Furthermore, a number of intermediate filament proteins have been involved in the acquisition of tumorigenic properties. Over the last years, a strong involvement of intermediate filament proteins in the regulation of several aspects of intracellular trafficking has strongly emerged. Here, we review the functions of intermediate filaments proteins focusing mainly on the recent knowledge gained from the discovery that intermediate filaments associate with key proteins of the vesicular membrane transport machinery. In particular, we analyze the current understanding of the contribution of intermediate filaments to the endocytic pathway. PMID:27120621

  20. THE FUNCTIONS OF FINANCIAL INTERMEDIATION - A SURVEY

    OpenAIRE

    Andries Marius Alin

    2009-01-01

    Traditional theories of intermediation are based on transaction costs and asymmetric information. In recent decades although transaction costs and asymmetric information have declined, intermediation has increased. New markets for financial futures and options are mainly markets for intermediaries rather than individuals or firms. In this paper we survey the last theoretical and empirical research on financial intermediation and functions of financial intermediation. We discuss the functions ...

  1. How Should Financial Intermediation Services be Taxed?

    OpenAIRE

    Lockwood, Ben

    2010-01-01

    This paper considers the optimal taxation of two types of financial intermediation services (savings intermediation, and payment services) in a dynamic general equilibrium setting, when the government can also use consumption and income taxes. When payment services are used in strict proportion to final consumption, and the cost of intermediation services is the same across firms, the optimal taxes on financial intermediation are generally indeterminate. But, when firms differ in the cost of ...

  2. Intermediate Filaments in Caenorhabditis elegans.

    Science.gov (United States)

    Zuela, Noam; Gruenbaum, Yosef

    2016-01-01

    More than 70 different genes in humans and 12 different genes in Caenorhabditis elegans encode the superfamily of intermediate filament (IF) proteins. In C. elegans, similar to humans, these proteins are expressed in a cell- and tissue-specific manner, can assemble into heteropolymers and into 5-10nm wide filaments that account for the principal structural elements at the nuclear periphery, nucleoplasm, and cytoplasm. At least 5 of the 11 cytoplasmic IFs, as well as the nuclear IF, lamin, are essential. In this chapter, we will include a short review of our current knowledge of both cytoplasmic and nuclear IFs in C. elegans and will describe techniques used for their analyses.

  3. ESL intermediate/advanced writing

    CERN Document Server

    Munoz Page, Mary Ellen; Jaskiewicz, Mary

    2011-01-01

    Master ESL (English as a Second Language) Writing with the study guide designed for non-native speakers of English. Skill-building lessons relevant to today's topics help ESL students write complete sentences, paragraphs, and even multi-paragraph essays. It's perfect for classroom use or self-guided writing preparation.DETAILS- Intermediate drills for improving skills with parallel structure, mood, correct shifting errors & dangling participles- Advanced essay drills focusing on narrative, descriptive, process, reaction, comparison and contrast- Superb preparation for students taking the TOEFL

  4. 34 CFR 200.17 - Intermediate goals.

    Science.gov (United States)

    2010-07-01

    ... 34 Education 1 2010-07-01 2010-07-01 false Intermediate goals. 200.17 Section 200.17 Education... Programs Operated by Local Educational Agencies Adequate Yearly Progress (ayp) § 200.17 Intermediate goals. Each State must establish intermediate goals that increase in equal increments over the period...

  5. Intermediate view synthesis from stereoscopic images

    Institute of Scientific and Technical Information of China (English)

    Lü Chaohui; An Ping; Zhang Zhaoyang

    2005-01-01

    A new method is proposed for synthesizing intermediate views from a pair of stereoscopic images. In order to synthesize high-quality intermediate views, the block matching method together with a simplified multi-window technique and dynamic programming is used in the process of disparity estimation. Then occlusion detection is performed to locate occluded regions and their disparities are compensated. After the projecton of the left-to-right and right-to-left disparities onto the intermediate image, intermediate view is synthesized considering occluded regions. Experimental results show that our synthesis method can obtain intermediate views with higher quality.

  6. 光滑念珠菌 Cdc42基因生物信息分析%Bioinformatics Analysis of Cdc42 Gene from Candida Glabrata

    Institute of Scientific and Technical Information of China (English)

    赵静; 黄怀球; 袁立燕; 钟毅; 张静; 张晓辉

    2013-01-01

    目的:分析和预测光滑念珠菌Cdc42基因及其编码蛋白的结构和特性。方法:利用NCBI、Ex-PASy和CBS网站中的各种信息分析工具,并结合Vector NTI suite 8.0生物信息学分析软件包,分析预测光滑念珠菌Cdc42基因并预测该基因编码蛋白结构的特征和功能。结果:Cdc42基因全长为576 bp,编码区具有191个氨基酸,在GenBank同源序列中,其与酵母 Cdc42氨基酸序列一致性达到99%,且有Cdc42保守域。 Cdc42蛋白相对分子量预测为21420.83,理论等电点为6.31。预测Cdc42编码蛋白ɑ螺旋(H)、β折叠(E)、无规则卷(L)的比例分别是29.84%、28.70%、41.88%,1个GTP/ATP结合位点。 Cdc42蛋白为疏水蛋白,无跨膜区,无信号肽。结论:成功预测Cdc42基因及编码蛋白生化及结构特征,为下一步对其进行克隆和表达奠定基础。%Objective:To analyze and predict the structure and properties about encoding pro-tein of cell division cycle 42(Cdc42) from Candida glabrata by bioinformatics.Methods:A full-length cDNA sequence encoding Cdc 42 from Candida glabrata was identified by using tools of bioinformatics at webs sites of NCBI , ExPASy, CBS and software Vector NTI suite 8.0.The char-acteristics of the protein were predicted by employing bioinformatics software package supplied by the website of ExPaSy .Results:The full length of Cdc42 is 576 bp, and its ORF encodes 191 ami-no acid.The relationship of phylogenesis between Candida glabrata and other fungus is close .The prediction shows that Cdc 42 had a Cdc42 conserved domain , the molecular weight and theoretical pI of Cg.Cdc42 was 21 420.83 and 6.31 respectively, and the coding protein contains 29.84%ɑ-helix, 28.70%extended strand,41.88% random coil,and one GTP/ATP motif.Cdc42 enco-ding protein is hydrophobic , extra-membrane protein , without signal peptide .Conclusion:The structure and characteristics of the gene and protein of Cg .Cdc42 was

  7. Intermediate inflation from rainbow gravity

    CERN Document Server

    Barrow, John D

    2013-01-01

    It is possible to dualize theories based on deformed dispersion relations and Einstein gravity so as to map them into theories with trivial dispersion relations and rainbow gravity. This often leads to "dual inflation" without the usual breaking of the strong energy condition. We identify the dispersion relations in the original frame which map into "intermediate" inflationary models. These turn out to be particularly simple: power-laws modulated by powers of a logarithm. The fluctuations predicted by these scenarios are near, but not exactly scale-invariant, with a red running spectral index. These dispersion relations deserve further study within the context of quantum gravity and the phenomenon of dimensional reduction in the ultraviolet.

  8. Intermediate Jacobians of moduli spaces

    CERN Document Server

    Arapura, D; Arapura, Donu; Sastry, Pramathanath

    1996-01-01

    Let $SU_X(n,L)$ be the moduli space of rank n semistable vector bundles with fixed determinant L on a smooth projective genus g curve X. Let $SU_X^s(n,L)$ denote the open subset parametrizing stable bundles. We show that if g>3 and n > 1, then the mixed Hodge structure on $H^3(SU_X^s(n, L))$ is pure of type ${(1,2),(2,1)}$ and it carries a natural polarization such that the associated polarized intermediate Jacobian is isomorphic J(X). This is new when deg L and n are not coprime. As a corollary, we obtain a Torelli theorem that says roughly that $SU_X^s(n,L)$ (or $SU_X(n,L)$) determines X. This complements or refines earlier results of Balaji, Kouvidakis-Pantev, Mumford-Newstead, Narasimhan-Ramanan, and Tyurin.

  9. Comportamento reológico de méis de florada de silvestre Rheological behavior of honey from Serjania glabrata flowers

    Directory of Open Access Journals (Sweden)

    Alexandre J. de M. Queiroz

    2007-04-01

    Full Text Available Estudou-se o comportamento reológico de méis de Apis mellifera produzidos no estado do Piauí, no semi-árido brasileiro, elaborados com florada predominante de silvestre (Serjania glabrata. As amostras foram coletadas ao longo do ano 2000, a partir de coletas realizadas por apicultores, associações e cooperativas de apicultura da região abrangida pelos municípios de Picos, Itainópolis, Vera Mendes e Isaías Coelho. Após as coletas as amostras passaram pelos processos de centrifugação, filtragem e decantação. As medidas reológicas foram feitas nas temperaturas de 20 a 40 ºC utilizando-se um viscosímetro Brookfield, modelo RVT. As leituras de velocidade de rotação e torque foram transformadas em valores de taxa de deformação e tensão de cisalhamento. Os dados de taxa de deformação e tensão de cisalhamento foram ajustados pelas equações da Lei-da-Potência e de Herschel-Bulkley. As amostras apresentaram comportamento pseudoplástico. As equações se ajustaram adequadamente aos resultados experimentais de tensão de cisalhamento em função da taxa de deformação. O aumento de temperatura reduziu a viscosidade aparente em níveis próximos de 80%. Os valores de viscosidade aparente foram bem ajustados por uma equação do tipo Arrhenius.The rheological behavior of Apis mellifera honey produced in the State of Piauí, in the Brazilian semi-arid, obtained with predominance of Serjania glabrata flowers was studied. The samples were collected in the year 2000 by beekeepers and associations and cooperatives of beekeepers in the area covered by the municipal districts of Picos, Itainópolis, Vera Mendes and Isaías Coelho. The samples were centrifuged, filtered, decanted and the rheological measures at temperatures of 20 to 40 ºC using a Brookfield Viscometer RVT model were made. The readings of rotation speed and torque were transformed in shear rate and shear stress values. The data of shear rate and shear stress were fitted

  10. New insights into the structure of (1→3,1→6-β-D-glucan side chains in the Candida glabrata cell wall.

    Directory of Open Access Journals (Sweden)

    Douglas W Lowman

    Full Text Available β-Glucan is a (1→3-β-linked glucose polymer with (1→6-β-linked side chains and a major component of fungal cell walls. β-Glucans provide structural integrity to the fungal cell wall. The nature of the (1-6-β-linked side chain structure of fungal (1→3,1→6-β-D-glucans has been very difficult to elucidate. Herein, we report the first detailed structural characterization of the (1→6-β-linked side chains of Candida glabrata using high-field NMR. The (1→6-β-linked side chains have an average length of 4 to 5 repeat units spaced every 21 repeat units along the (1→3-linked polymer backbone. Computer modeling suggests that the side chains have a bent curve structure that allows for a flexible interconnection with parallel (1→3-β-D-glucan polymers, and/or as a point of attachment for proteins. Based on these observations we propose new approaches to how (1→6-β-linked side chains interconnect with neighboring glucan polymers in a manner that maximizes fungal cell wall strength, while also allowing for flexibility, or plasticity.

  11. FINANCIAL INTERMEDIATION, ENTREPRENEURSHIP AND ECONOMIC GROWTH

    OpenAIRE

    Wenli Cheng

    2007-01-01

    This paper presents a simple general equilibrium model of financial intermediation, entrepreneurship and economic growth. In this model, the role of financial intermediation is to pool savings and to lend the pooled funds to an entrepreneur, who in turn invests the funds in a new production technology. The adoption of the new production technology improves individual real income. Thus financial intermediation promotes economic growth through affecting individuals’ saving behaviour and enabl...

  12. How should Financial Intermediation Services be Taxed?

    OpenAIRE

    Lockwood, Ben

    2010-01-01

    This paper considers the optimal taxation of savings intermediation and payment services in a dynamic general equilibrium setting, when the government can also use consumption and income taxes. When payment services are used in strict proportion to final consumption, and the cost of intermediation services is fixed and the same across firms, the optimal taxes are generally indeterminate. But, when firms differ exogenously in the cost of intermediation services, the tax on savings intermediati...

  13. Experiments in intermediate energy physics

    Energy Technology Data Exchange (ETDEWEB)

    Dehnhard, D.

    2003-02-28

    Research in experimental nuclear physics was done from 1979 to 2002 primarily at intermediate energy facilities that provide pion, proton, and kaon beams. Particularly successful has been the work at the Los Alamos Meson Physics Facility (LAMPF) on unraveling the neutron and proton contributions to nuclear ground state and transition densities. This work was done on a wide variety of nuclei and with great detail on the carbon, oxygen, and helium isotopes. Some of the investigations involved the use of polarized targets which allowed the extraction of information on the spin-dependent part of the triangle-nucleon interaction. At the Indiana University Cyclotron Facility (IUCF) we studied proton-induced charge exchange reactions with results of importance to astrophysics and the nuclear few-body problem. During the first few years, the analysis of heavy-ion nucleus scattering data that had been taken prior to 1979 was completed. During the last few years we created hypernuclei by use of a kaon beam at Brookhaven National Laboratory (BNL) and an electron beam at Jefferson Laboratory (JLab). The data taken at BNL for a study of the non-mesonic weak decay of the A particle in a nucleus are still under analysis by our collaborators. The work at JLab resulted in the best resolution hypernuclear spectra measured thus far with magnetic spectrometers.

  14. Some Intermediate-Level Violin Concertos.

    Science.gov (United States)

    Abramson, Michael

    1997-01-01

    Contends that many violin students attempt difficult concertos before they are technically or musically prepared. Identifies a variety of concertos at the intermediate and advanced intermediate-level for students to study and master before attempting the advanced works by Bach and Mozart. Includes concertos by Vivaldi, Leclair, Viotti, Haydn,…

  15. Intermediate energy nuclear data for applications

    International Nuclear Information System (INIS)

    A comprehensive review of the data needs for various applications was performed by the participants of the meeting. The status of compilation and evaluation of the needed data in the intermediate energy range of incident particles was discussed. The following broad application areas were identified and considered by the participants: intermediate energy nuclear data needed for accelerators; intermediate energy nuclear data needed for space applications; intermediate energy nuclear data for medical applications. The role of nuclear model calculations in data evaluations in this energy range was considered. The possibilities of existing model codes were considered from the point of view of reliability, accuracy, cost of computer time, availability to specialists in the Member States. The Meeting presentations were divided into the following three sessions: Nuclear data needs in the intermediate energy range (6 papers), Progress of nuclear data computations and evaluations in the intermediate energy range (6 papers) and Progress of experimental data measurements in the intermediate energy range. A separate abstract was prepared for each paper. The ways of further improvement of the status of nuclear data in the intermediate energy range were discussed and the results of these discussions can be found in the conclusions and recommendations of this meeting. Refs, figs and tabs

  16. Air Conditioning. Performance Objectives. Intermediate Course.

    Science.gov (United States)

    Long, William

    Several intermediate performance objectives and corresponding criterion measures are listed for each of seven terminal objectives for an intermediate air conditioning course. The titles of the seven terminal objectives are Refrigeration Cycle, Job Requirement Skills, Air Conditioning, Trouble Shooting, Performance Test, Shop Management, and S.I.E.…

  17. Gasoline Engine Mechanics. Performance Objectives. Intermediate Course.

    Science.gov (United States)

    Jones, Marion

    Several intermediate performance objectives and corresponding criterion measures are listed for each of six terminal objectives presented in this curriculum guide for an intermediate gasoline engine mechanics course at the secondary level. (For the beginning course guide see CE 010 947.) The materials were developed for a two-semester (2 hour…

  18. 19 CFR 122.84 - Intermediate airport.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Intermediate airport. 122.84 Section 122.84... Intermediate airport. (a) Application. The provisions of this section apply at any U.S. airport to which an... aircraft arrives at the next airport, the aircraft commander or agent shall make entry by filing the:...

  19. Interaction of gamma radiation on the functionality of the molluscicidal extract of Anacardium occidentale Linn

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Gustavo Henrique Farias dos [Grupo de Estudos em Radioprotecao e Radioecologia (GERAR) . Departamento de Energia Nuclear. Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Silva, Edvane Borges da [Centro Academico de Vitoria. Universidade Federal de Pernambuco (UFPE), Vitoria de Santo Antao, PE (Brazil); Amorim, Elba Lucia C.; Peixoto Sobrinho, Tadeu J.S., E-mail: elba@ufpe.br [Departamento de Ciencias Farmaceuticas. Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Melo, Ana Maria Mendonca de Albuquerque; Lima, Claudia Sampaio de Andrade [Departamento de Biofisica e Radiobiologia. Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil)

    2011-07-01

    Biological control of Biomphalaria glabrata that is the intermediate host of Schistosoma mansoni, through molluscicides has been an alternative against schistosomiasis. Many studies have been developed to obtain molluscicide products, from plants. Anacardium occidentale L. (cashew), a plant rich in phenolic compounds shows molluscicidal activity in earlier assays. However there is an interest of enhancing the action of bioactive substances in order to use it in small concentrations, reducing costs in their utilization. This study were conducted using ethanolic extracts of bark and leaves of A. occidentale, before and after exposure to gamma radiation from {sup 60}Co, checking their secondary metabolites, their biological activity against Biomphalaria glabrata and environmental toxicity. The extracts of A. occidentale were obtained by cold maceration in 70% ethanol, filtered, dried and divided into two experimental groups: control (0 kGy) and irradiated at a dose of 10 kGy. The quantification of metabolites was performed in six replicates for the determination of total phenols by Folin-Ciocalteau method and tannins, the precipitation of casein. Tests for biological control of embryos and adults of B. glabrata snails and assessment of environmental toxicity (using Artemia salina larvae) were performed in triplicate, following a period of 24 hours of exposure to extracts at a concentration of 100 mg/L and its respective controls. Data were expressed as percentages of means and standard deviations. The results showed that the gamma radiation from {sup 60}Co resulted in leaf extracts, increased levels of total phenols and tannins, which enhanced the lethality for embryos and adults of B. glabrata. There was a reduction of the toxicity of leaf extracts after irradiation in the Artemia salina. Since in extracts of bark, gamma radiation did not alter the levels of total phenols and tannins, however, it was noted potentiation of lethality of adult snails of B. glabrata. The

  20. Interaction of gamma radiation on the functionality of the molluscicidal extract of Anacardium occidentale Linn

    International Nuclear Information System (INIS)

    Biological control of Biomphalaria glabrata that is the intermediate host of Schistosoma mansoni, through molluscicides has been an alternative against schistosomiasis. Many studies have been developed to obtain molluscicide products, from plants. Anacardium occidentale L. (cashew), a plant rich in phenolic compounds shows molluscicidal activity in earlier assays. However there is an interest of enhancing the action of bioactive substances in order to use it in small concentrations, reducing costs in their utilization. This study were conducted using ethanolic extracts of bark and leaves of A. occidentale, before and after exposure to gamma radiation from 60Co, checking their secondary metabolites, their biological activity against Biomphalaria glabrata and environmental toxicity. The extracts of A. occidentale were obtained by cold maceration in 70% ethanol, filtered, dried and divided into two experimental groups: control (0 kGy) and irradiated at a dose of 10 kGy. The quantification of metabolites was performed in six replicates for the determination of total phenols by Folin-Ciocalteau method and tannins, the precipitation of casein. Tests for biological control of embryos and adults of B. glabrata snails and assessment of environmental toxicity (using Artemia salina larvae) were performed in triplicate, following a period of 24 hours of exposure to extracts at a concentration of 100 mg/L and its respective controls. Data were expressed as percentages of means and standard deviations. The results showed that the gamma radiation from 60Co resulted in leaf extracts, increased levels of total phenols and tannins, which enhanced the lethality for embryos and adults of B. glabrata. There was a reduction of the toxicity of leaf extracts after irradiation in the Artemia salina. Since in extracts of bark, gamma radiation did not alter the levels of total phenols and tannins, however, it was noted potentiation of lethality of adult snails of B. glabrata. The analysis

  1. Analysis of ERG11 gene mutations in fluconazole-resistant Candida glabrata strains%耐氟康唑光滑念珠菌ERG11基因突变分析

    Institute of Scientific and Technical Information of China (English)

    沈银忠; 卢洪洲; 张永信

    2010-01-01

    Objective To study the mutations of ERG11 gene which encodes P450 lanosterol 14-α demethylase, and to explore the possible role of ERG11 gene in inducing fluconazole resistance in Candida glabrata. Methods ERG11 genes of 9 fluconazole-resistant Candida glabrata isolates and 10 fluconazole-sensitive Candida glabrata isolates were cloned into pUC57-T vector. The open reading frame of ERG11 gene were sequenced by two directional sequencing using universal primers. All sequences were compared with the published sequence. Results Ten kinds of synonymous point mutation were found. Neither missense mutation nor frame-shifting mutation was found. Among the 10 kinds of synonymous point mutation, 5 were found in both fluconazole-resistant and fluconazolesensitive Candida glabrata isolates, and 3 were only found in fluconazole-resistant isolates, 2 were only found in fluconazole-sensitive ones. The majority of the point mutations were located between 1320-2200 base pair of ERG11 gene. Conclusions There are ERG11 gene polymorphisms in clinical strains of Candida glabrata. ERG11 gene mutations are not found to be involved in the development of fluconazole resistance in Candida glabrata.%目的 分析耐药氟康唑光滑念珠菌ERG11基因突变情况,探讨ERG11基因突变在光滑念珠菌耐药性形成中的作用.方法 分别将氟康唑耐药光滑念珠菌株9株和敏感株10株的ERG11基因克隆至pUC57-T载体,利用载体上的通用引物对其ERG11基因整个开放读码框进行双向测序,将测序结果与网上公布的标准序列进行比对.结果 19株光滑念珠菌耐药株和敏感株ERG11基因共存在10个点突变,均为同义突变,无错义突变和移码突变.其中5个点突变在耐药株和敏感株中均出现,3个只出现在耐药株,2个只出现在敏感株.点突变主要位于ERG11基因1320~2200 bp,出现频率最高的3个点突变为T2117A、A1583G、T1328C.结论 光滑念珠菌ERG11基因序列

  2. The proteome of the Torulopsis glabrata under hyperosmotic stress%高渗胁迫对光滑球拟酵母蛋白质组的影响

    Institute of Scientific and Technical Information of China (English)

    徐沙; 刘立明

    2014-01-01

    光滑球拟酵母(Torulopsis glabrata)在生产丙酮酸的过程中,发酵液渗透压不断提高,导致细胞生长缓慢,影响丙酮酸的持续积累.实验通过二维电泳和同位素标记相对和绝对定量(iTRAQ)技术,比较不同渗透压条件下蛋白质组的差异.结果表明,在渗透压为1 765、2 603和3 324 mOsmol/kg时,相对于对照条件(860mOsmol/kg),分别有125、91和109个蛋白表达水平上调,94、89和78个蛋白表达水平下调,其中中心代谢和能量代谢途径的蛋白质表达量明显提高.此外,研究还发现,渗透压胁迫可诱导超氧化物歧化酶和富脯蛋白的表达量增加,前者可能和高渗环境下活性氧簇的积累有关,而后者可能与胞内脯氨酸的积累有关.该文为后续研究如何提高T.glabrata抵御高渗胁迫的能力提供理论依据.

  3. Language in use intermediate : classroom book

    CERN Document Server

    Doff, Adrian

    1995-01-01

    ach of the four levels comprises about 80 hours of class work, with additional time for the self-study work. The Teacher's Book contains all the pages from the Classroom Book, with interleaved teaching notes including optional activities to cater for different abilities. There is a video to accompany the Beginner, Pre-intermediate and Intermediate levels. Each video contains eight stimulating and entertaining short programmes, as well as a booklet of photocopiable activities. Free test material is available in booklet and web format for Beginner and Pre-intermediate levels. Visit www.cambridge.org/elt/liu or contact your local Cambridge University Press representative.

  4. Language in use intermediate : teacher's book

    CERN Document Server

    Doff, Adrian

    1998-01-01

    Each of the four levels comprises about 80 hours of class work, with additional time for the self-study work. The Teacher's Book contains all the pages from the Classroom Book, with interleaved teaching notes including optional activities to cater for different abilities. There is a video to accompany the Beginner, Pre-intermediate and Intermediate levels. Each video contains eight stimulating and entertaining short programmes, as well as a booklet of photocopiable activities. Free test material is available in booklet and web format for Beginner and Pre-intermediate levels. Visit www.cambridge.org/elt/liu or contact your local Cambridge University Press representative.

  5. Directional spread parameter at intermediate water depth

    Digital Repository Service at National Institute of Oceanography (India)

    SanilKumar, V.; Deo, M.C.; Anand, N.M.; AshokKumar, K.

    The characteristics of directional spread parameters at intermediate water depth are investigated based on a cosine power '2s' directional spreading model. This is based on wave measurements carried out using a Datawell directional waverider buoy...

  6. Intermediate/Advanced Research Design and Statistics

    Science.gov (United States)

    Ploutz-Snyder, Robert

    2009-01-01

    The purpose of this module is To provide Institutional Researchers (IRs) with an understanding of the principles of advanced research design and the intermediate/advanced statistical procedures consistent with such designs

  7. Bursts of intermediate ions in atmospheric air

    Science.gov (United States)

    Hõrrak, U.; Salm, J.; Tammet, H.

    1998-06-01

    The mobility spectrum of air ions has been measured at Tahkuse Observatory in Estonia for several years. The average concentration of intermediate ions with mobilities of 0.05-0.5 cm2 V-1 s-1 in atmospheric air is about 50 cm-3. On the level of this low background, high concentration bursts of intermediate air ions occur occasionally. A burst can be followed by subsequent evolution of intermediate ions into larger ones. To explain the bursts of intermediate air ions, two hypotheses can be advanced: (1)A burst of neutral particles occurs due to homogeneous nucleation, and the particles are charged by the attachment of cluster ions. (2) The cluster ions grow by ion-induced nucleation in proper environmental conditions.

  8. The second national audit of intermediate care.

    Science.gov (United States)

    Young, John; Gladman, John R F; Forsyth, Duncan R; Holditch, Claire

    2015-03-01

    Intermediate care services have developed internationally to expedite discharge from hospital and to provide an alternative to an emergency hospital admission. Inconsistencies in the evidence base and under-developed governance structures led to concerns about the care quality, outcomes and provision of intermediate care in the NHS. The National Audit of Intermediate Care was therefore established by an interdisciplinary group. The second national audit reported in 2013 and included crisis response teams, home-based and bed-based services in approximately a half of the NHS. The main findings were evidence of weak local strategic planning, considerable under-provision, delays in accessing the services and lack of mental health involvement in care. There was a very high level of positive patient experience reported across all types of intermediate care, though reported involvement with care decisions was less satisfactory.

  9. On financial equilibrium with intermediation costs

    DEFF Research Database (Denmark)

    Markeprand, Tobias Ejnar

    2008-01-01

    This paper studies the set of competitive equilibria in financial economies with intermediation costs. We consider an arbitrary dividend structure, which includes options and equity with limited liabilities.We show a general existence result and upper-hemi continuity of the equilibrium correspond......This paper studies the set of competitive equilibria in financial economies with intermediation costs. We consider an arbitrary dividend structure, which includes options and equity with limited liabilities.We show a general existence result and upper-hemi continuity of the equilibrium...... correspondence. Finally, we prove that when intermediation costs approach zero, unbounded volume of asset trades is a necessary and sufficient condition, provided that, there is no financial equilibrium without intermediation costs....

  10. Some Aspects of Intermediate mass black holes

    OpenAIRE

    Sivaram, C; Arun, Kenath

    2007-01-01

    There is a lot of current astrophysical evidence and interest in intermediate mass black holes, ranging from a few hundred to several thousand solar masses. The active galaxy M82 and the globular cluster in M31, for example, are known to host such objects. Here we discuss several aspects of intermediate mass black holes such as their expected luminosity, spectral nature of radiation, associated jets, etc. We also discuss possible scenarios for their formation including the effects of dynamica...

  11. Has Banks’ Financial Intermediation Improved in Russia?

    OpenAIRE

    Fungachova, Z.; Solanko, L.

    2010-01-01

    The aim of this paper is to analyze the increasing importance of banks in the Russian economy over the period following the financial crisis of 1998. We use several measures to assess the role of banks in domestic financial intermediation in Russia. The traditional macro-level view is complemented by the analysis of sectoral financial flows as well as by insights from micro-level studies. All of these confirm that banks are becoming increasingly important in financial intermediation. We find ...

  12. The measurement of financial intermediation in Japan

    OpenAIRE

    Gunther Capelle-Blancard; Jézabel Couppey-Soubeyran; Laurent Soulat

    2005-01-01

    In this paper, we compute financial intermediation ratios for Japan (1970-2003) on a book value basis. According to our results, the intermediation ratio has remained quite stable, at around 85%. However, this stability is the result of two opposing trends : a decrease in credits and an increase in financial securities owned by financial (mostly, non banking) institutions. These two opposing trends would not have appeared if we had used traditional indicators computed as a fraction on GDP, or...

  13. Financial intermediation and occupational choice in development

    OpenAIRE

    Erosa, Andrés

    2000-01-01

    This paper presents evidence that the spread between the marginal product of capital and the return on financial assets is mich higher in poor than in rich countries. A model with costly intermediation is developed. In this economy, individuals choose at each instant whether to work or to operate a technology. Entrepreneurs finance their business with their own savings and, if necessary, by borrowing from banks. I find that in this framework intermediation costs are not equivalent to a tax on...

  14. Firm. An intermediate language for compiler research

    OpenAIRE

    Beck, Michael; Boesler, Boris; Geiß, Rubino; Lindenmaier, Götz

    2005-01-01

    State of the art compiler intermediate representations incorporate SSA data dependencies in a graph based manner. We present the intermediate representation Firm, which extends the functional stores of Steensgard and introduces a novel representation of exceptions. Firm offers a high-level representation of the type hierarchy and object-oriented features, which makes it exceptional suitable for analysing and optimizing of strongly typed languages. The co...

  15. Activity of Euphorbia splendens var. hislopii N.E.B. (Euphorbiaceae latex against Lymnaea columella (Say, 1817 (Pulmonata: Lymnaeidae, intermediate host of Fasciola hepatica, Linnaeus, 1758 (Trematoda: Fasciolidae. 2: limited field-testing

    Directory of Open Access Journals (Sweden)

    Mauricio Carvalho de Vasconcellos

    2003-10-01

    Full Text Available The molluscicidal evaluation of Euphorbia splendens var. hislopii (Crown of thorns against Lymnaea columella snails, intermediate host of Fasciola hepatica, in irrigation ditches of the Pisciculture Station at Universidade Federal Rural do Rio de Janeiro, was studied under limited field conditions. An aqueous solution of the latex at 5 mg/l was tested in two irrigation ditches (experimental and control ditches, after initial sampling of the snail population present. Twenty-four hours after application of the product, it was verified that 97.4% of free L. columella snails and 100% of snails of the same species captive in cages and used as sentinels at three points equidistant from the application site in the experimental ditch, died. For Biomphalaria tenagophila and Melanoides tuberculata snails, present in the experimental ditch, the mortality was 100%, for the species Pomacea spp. the mortality was 40%. No mortality was verified in the free mollusks, or in the sentinels in the ditch used as control. E. splendens var. hislopii latex is thus an efficient natural molluscicide, which may be used as an alternative control agent against L. columella.

  16. Levantamento malacológico em parques urbanos de Belo Horizonte, Minas Gerais, Brasil A malacological survey in city parks in Belo Horizonte, Minas Gerais, Brasil

    Directory of Open Access Journals (Sweden)

    Carlos Tito Guimarães

    1997-04-01

    Full Text Available Existem atualmente na região metropolitana de Belo Horizonte 18 parques urbanos (também denominados "parques ecológicos" com coleções hídricas (lagoas, nascentes, córregos etc. Pesquisas iniciais em 17 destes parques mostraram a ocorrência de moluscos hospedeiros intermediários do Schistosoma mansoni em pelo menos quatro deles. Capturas mensais nestes parques, de agosto/94 a fevereiro/96, mostraram os seguintes resultados em relação aos planorbíneos: Parque Julien Rien: 1.145 exemplares de Biomphalaria glabrata (2 mm a 13 mm; Parque Betânia: 149 exemplares de B. glabrata (4 mm a 13 mm; Parque Santa Lúcia: 2.431 exemplares de B. straminea (3 mm a 9 mm e Parque Lagoa do Nado: três exemplares de B. tenagophila (3 mm a 10 mm. As visitas aos parques terão prosseguimento e, após um diagnóstico sobre a situação de cada parque, serão sugeridas às autoridades municipais medidas de controle e/ou erradicação adequadas a cada área.The Greater Metropolitan Area of Belo Horizonte currently contains 18 city parks (also known as "ecological parks" with various bodies of water (lakes, springs, streams, etc. Initial research in 17 of these parks showed the occurrence of intermediate mollusk hosts for Schistosoma mansoni in at least 4. Monthly captures done from August 1994 to February 1996 showed the following results for these planorbids: Julien Rien Park: 1,145 specimens of Biomphalaria glabrata (2 to 13 mm; Betânia Park: 149 specimens of B. glabrata (4 to 13 mm; Santa Lúcia Park: 2,431 specimens of B. straminea (3 to 9 mm; and Lagoa do Nado Park: 3 specimens of B. tenagophila (3 to 10 mm. Visits to the parks will continue, and after a diagnosis of each park's situation, control and/or eradication measures suitable for each one will be proposed to the municipal authorities.

  17. A Benzoic Acid Derivative and Flavokawains from Piper species as Schistosomiasis Vector Controls

    Directory of Open Access Journals (Sweden)

    Ludmila N. Rapado

    2014-04-01

    Full Text Available The search of alternative compounds to control tropical diseases such as schistosomiasis has pointed to secondary metabolites derived from natural sources. Piper species are candidates in strategies to control the transmission of schistosomiasis due to their production of molluscicidal compounds. A new benzoic acid derivative and three flavokawains from Piper diospyrifolium, P. cumanense and P. gaudichaudianum displayed significant activities against Biomphalaria glabrata snails. Additionally, “in silico” studies were performed using docking assays and Molecular Interaction Fields to evaluate the physical-chemical differences among the compounds in order to characterize the observed activities of the test compounds against Biomphalaria glabrata snails.

  18. Phytochemical study and evaluation of the molluscicidal activity of Calophyllum brasiliense Camb (Clusiaceae); Estudo fitoquimico e avaliacao da atividade moluscicida do Calophyllum brasiliense Camb (Clusiaceae)

    Energy Technology Data Exchange (ETDEWEB)

    Gasparotto Junior, Arquimedes; Brenzan, Mislaine Adriana; Piloto, Izabel Cristina; Cortez, Diogenes Aparicio Garcia [Universidade Estadual de Maringa, PR (Brazil). Dept. de Farmacia e Farmacologia]. E-mail: dagcortez@uem.br; Nakamura, Celso Vataru; Dias Filho, Benedito Prado [Universidade Estadual de Maringa, PR (Brazil). Dept. de Analises Clinicas; Rodrigues Filho, Edson; Ferreira, Antonio Gilberto [Sao Carlos Univ., SP (Brazil). Dept. de Quimica

    2005-07-15

    The bioassay-guided fractionation against Biomphalaria glabrata of hydroalcoholic extracts of Calophyllum brasiliense aerial parts led to the isolation of the coumarin, named (-) mammea A/BB. The compound had its structure determined by both spectroscopic techniques (NMR {sup 1}H, NMR {sup 13}C, gHSQC, gHMBC and MS) and some literature comparison data. The probit analysis of (-) mammea A/BB showed LD{sub 50} = 0.67 ppm and LD{sub 90} = 1.47 ppm. In addition, the dichloromethane extract obtained from C. brasiliense leaves with significant molluscicidal activity against Biomphalaria glabrata was analyzed by HPLC-UV. (author)

  19. Diagnóstico da esquistossomose mansônica mediante técnica de imunofluorescência com esporocistos em tecidos de planorbídeos Diagnosis of mansoni schistosomiasis by means of immunofluorescent technique using sporocysts in planorbid tissues

    Directory of Open Access Journals (Sweden)

    Ana Maria Aparecida Guaraldo

    1981-12-01

    Full Text Available Propõe-se uma técnica de imunofluorescência para diagnóstico da esquistossomose mansônica, adotando-se tecidos de Biomphalaria glabrata contendo esporocistos secundários de Schistosoma mansoni. A reação de imunofluorescência indireta é executada sobre cortes histológicos preparados por inclusão em parafina.An immunofluorescent technique is proposed for diagnosis of mansoni schistosomiasis using Biomphalaria glabrata tissue with secondary sporocysts. The indirect immunofluorescent reaction is carried out on histological sections prepared by embedding in paraffin.

  20. Partially folded intermediates during trypsinogen denaturation

    Directory of Open Access Journals (Sweden)

    Martins N.F.

    1999-01-01

    Full Text Available The equilibrium unfolding of bovine trypsinogen was studied by circular dichroism, differential spectra and size exclusion HPLC. The change in free energy of denaturation was = 6.99 ± 1.40 kcal/mol for guanidine hydrochloride and = 6.37 ± 0.57 kcal/mol for urea. Satisfactory fits of equilibrium unfolding transitions required a three-state model involving an intermediate in addition to the native and unfolded forms. Size exclusion HPLC allowed the detection of an intermediate population of trypsinogen whose Stokes radii varied from 24.1 ± 0.4 Å to 26.0 ± 0.3 Å for 1.5 M and 2.5 M guanidine hydrochloride, respectively. During urea denaturation, the range of Stokes radii varied from 23.9 ± 0.3 Å to 25.7 ± 0.6 Å for 4.0 M and 6.0 M urea, respectively. Maximal intrinsic fluorescence was observed at about 3.8 M urea with 8-aniline-1-naphthalene sulfonate (ANS binding. These experimental data indicate that the unfolding of bovine trypsinogen is not a simple transition and suggest that the equilibrium intermediate population comprises one intermediate that may be characterized as a molten globule. To obtain further insight by studying intermediates representing different stages of unfolding, we hope to gain a better understanding of the complex interrelations between protein conformation and energetics.

  1. Outflow forces in intermediate mass star formation

    CERN Document Server

    van Kempen, T A; van Dishoeck, E F; Kristensen, L E; Belloche, A; Klaassen, P D; Leurini, S; Jose-Garcia, I San; Aykutalp, A; Choi, Y; Endo, A; Frieswijk, W; Harsono, D; Karska, A; Koumpia, E; van der Marel, N; Nagy, Z; Perez-Beaupuits, J P; Risacher, C; van Weeren, R J; Wyrowski, F; Yildiz, U A; Guesten, R; Boland, W; Baryshev, A

    2015-01-01

    Intermediate mass protostarsprovide a bridge between theories of low- and high-mass star formation. Emerging molecular outflows can be used to determine the influence of fragmentation and multiplicity on protostellar evolution through the correlation of outflow forces of intermediate mass protostars with the luminosity. The aim of this paper is to derive outflow forces from outflows of six intermediate mass protostellar regions and validate the apparent correlation between total luminosity and outflow force seen in earlier work, as well as remove uncertainties caused by different methodology. By comparing CO 6--5 observations obtained with APEX with non-LTE radiative transfer model predictions, optical depths, temperatures, densities of the gas of the molecular outflows are derived. Outflow forces, dynamical timescales and kinetic luminosities are subsequently calculated. Outflow parameters, including the forces, were derived for all sources. Temperatures in excess of 50 K were found for all flows, in line wi...

  2. MNE Entrepreneurial Capabilities at Intermediate Levels

    DEFF Research Database (Denmark)

    Hoenen, Anne K.; Nell, Phillip Christopher; Ambos, Björn

    2014-01-01

    and on the heterogeneous information that is generated through dissimilar markets within the region. Our study opens up for an interesting discussion of the independence of these mechanisms. In sum, we contribute to the understanding of the entrepreneurial role of intermediate units in general and RHQs in particular.......This study investigates the entrepreneurial capabilities of MNE units at intermediate geographical levels, between the local subsidiary level and global corporate headquarters. In our conceptual development, we build on the entrepreneurship and MNE embeddedness literature to explain how MNE units...... at intermediate geographical levels differ from local subsidiaries and global corporate headquarters, and why those differences are important. We illustrate our arguments using data on European regional headquarters (RHQs). We find that RHQs' entrepreneurial capabilities depend on their external embeddedness...

  3. Intermediate-energy nuclear chemistry workshop

    International Nuclear Information System (INIS)

    This report contains the proceedings of the LAMPF Intermediate-Energy Nuclear Chemistry Workshop held in Los Alamos, New Mexico, June 23-27, 1980. The first two days of the Workshop were devoted to invited review talks highlighting current experimental and theoretical research activities in intermediate-energy nuclear chemistry and physics. Working panels representing major topic areas carried out indepth appraisals of present research and formulated recommendations for future research directions. The major topic areas were Pion-Nucleus Reactions, Nucleon-Nucleus Reactions and Nuclei Far from Stability, Mesonic Atoms, Exotic Interactions, New Theoretical Approaches, and New Experimental Techniques and New Nuclear Chemistry Facilities

  4. Intermediate-energy nuclear chemistry workshop

    Energy Technology Data Exchange (ETDEWEB)

    Butler, G.W.; Giesler, G.C.; Liu, L.C.; Dropesky, B.J.; Knight, J.D.; Lucero, F.; Orth, C.J.

    1981-05-01

    This report contains the proceedings of the LAMPF Intermediate-Energy Nuclear Chemistry Workshop held in Los Alamos, New Mexico, June 23-27, 1980. The first two days of the Workshop were devoted to invited review talks highlighting current experimental and theoretical research activities in intermediate-energy nuclear chemistry and physics. Working panels representing major topic areas carried out indepth appraisals of present research and formulated recommendations for future research directions. The major topic areas were Pion-Nucleus Reactions, Nucleon-Nucleus Reactions and Nuclei Far from Stability, Mesonic Atoms, Exotic Interactions, New Theoretical Approaches, and New Experimental Techniques and New Nuclear Chemistry Facilities.

  5. Governance-Default Risk Relationship and the Demand for Intermediated and Non-Intermediated Debt

    Directory of Open Access Journals (Sweden)

    Husam Aldamen

    2012-09-01

    Full Text Available This paper explores the impact of corporate governance on the demand for intermediated debt (asset finance, bank debt, non-bank private debt and non-intermediated debt (public debt in the Australian debt market. Relative to other countries the Australian debt market is characterised by higher proportions of intermediated or private debt with a lower inherent level of information asymmetry in that private lenders have greater access to financial information (Gray, Koh & Tong 2009. Our firm level, cross-sectional evidence suggests that higher corporate governance impacts demand for debt via the mitigation of default risk. However, this relationship is not uniform across all debt types. Intermediated debt such as bank and asset finance debt are more responsive to changes in governance-default risk relationship than non-bank and non-intermediated debt. The implication is that a firm’s demand for different debt types will reflect its governance-default risk profile.

  6. Saponins from Swartzia langsdorffii: biological activities

    OpenAIRE

    2003-01-01

    The presence of saponins and the molluscicidal activity of the roots, leaves, seeds and fruits of Swartzia langsdorffii Raddi (Leguminosae) against Biomphalaria glabrata adults and eggs were investigated. The roots, seeds and fruits were macerated in 95% ethanol. These extracts exerted a significant molluscicidal activity against B. glabrata, up to a dilution of 100 mg/l. Four mixtures (A2, B2, C and D) of triterpenoid oleanane type saponins were chromatographically isolated from the seed and...

  7. Modern Persian: Intermediate Level, Vol. 2.

    Science.gov (United States)

    Windfuhr, Gernot; And Others

    The second of three volumes of an intergrated course in intermediate Persian is presented. This volume encompasses material appropriate for students entering the second year of Persian studies who have strong preparation in elementary Persian. Verbal skills should be on a level which will allow comprehensive discussion of a topic using simple,…

  8. The GEOTRACES Intermediate Data Product 2014

    NARCIS (Netherlands)

    Mawji, Edward; Schlitzer, Reiner; Dodas, Elena Masferrer; Abadie, Cyril; Abouchami, Wafa; Anderson, Robert F.; Baars, Oliver; Bakker, Karel; Baskaran, Mark; Bates, Nicholas R.; Bluhm, Katrin; Bowie, Andrew; Bown, Johann; Boye, Marie; Boyle, Edward A.; Branellec, Pierre; Bruland, Kenneth W.; Brzezinski, Mark A.; Bucciarelli, Eva; Buesseler, Ken; Butler, Edward; Cai, Pinghe; Cardinal, Damien; Casciotti, Karen; Chaves, Joaquin; Cheng, Hai; Chever, Fanny; Church, Thomas M.; Colman, Albert S.; Conway, Tim M.; Croot, Peter L.; Cutter, Gregory A.; de Souza, Gregory F.; Dehairs, Frank; Deng, Feifei; Huong Thi Dieu, [Unknown; Dulaquais, Gabriel; Echegoyen-Sanz, Yolanda; Edwards, R. Lawrence; Fahrbach, Eberhard; Fitzsimmons, Jessica; Fleisher, Martin; Frank, Martin; Friedrich, Jana; Fripiat, Francois; Galer, Stephen J. G.; Gamo, Toshitaka; Solsona, Ester Garcia; Gerringa, Loes J. A.; Godoy, Jose Marcus; Gonzalez, Santiago; Grossteffan, Emilie; Hatta, Mariko; Hayes, Christopher T.; Heller, Maija Iris; Henderson, Gideon; Huang, Kuo-Fang; Jeandel, Catherine; Jenkins, William J.; John, Seth; Kenna, Timothy C.; Klunder, Maarten; Kretschmer, Sven; Kumamoto, Yuichiro; Laan, Patrick; Labatut, Marie; Lacan, Francois; Lam, Phoebe J.; Lannuzel, Delphine; le Moigne, Frederique; Lechtenfeld, Oliver J.; Lohan, Maeve C.; Lu, Yanbin; Masque, Pere; McClain, Charles R.; Measures, Christopher; Middag, Rob; Moffett, James; Navidad, Alicia; Nishioka, Jun; Noble, Abigail; Obata, Hajime; Ohnemus, Daniel C.; Owens, Stephanie; Planchon, Frederic; Pradoux, Catherine; Puigcorbe, Viena; Quay, Paul; Radic, Amandine; Rehkaemper, Mark; Remenyi, Tomas; Rijkenberg, Micha J. A.; Rintoul, Stephen; Robinson, Laura F.; Roeske, Tobias; Rosenberg, Mark; van der Loeff, Michiel Rutgers; Ryabenko, Evgenia; Saito, Mak A.; Roshan, Saeed; Salt, Lesley; Sarthou, Geraldine; Schauer, Ursula; Scott, Peter; Sedwick, Peter N.; Sha, Lijuan; Shiller, Alan M.; Sigman, Daniel M.; Smethie, William; Smith, Geoffrey J.; Sohrin, Yoshiki; Speich, Sabrina; Stichel, Torben; Stutsman, Johnny; Swift, James H.; Tagliabue, Alessandro; Thomas, Alexander; Tsunogai, Urumu; Twining, Benjamin S.; van Aken, Hendrik M.; van Heuven, Steven; van Ooijen, Jan; van Weerlee, Evaline; Venchiarutti, Celia; Voelker, Antje H. L.; Wake, Bronwyn; Warner, Mark J.; Woodward, E. Malcolm S.; Wu, Jingfeng; Wyatt, Neil; Yoshikawa, Hisayuki; Zheng, Xin-Yuan; Xue, Zichen; Zieringer, Moritz; Zimmer, Louise A.; de Baar, Henricus

    2015-01-01

    The GEOTRACES Intermediate Data Product 2014 (IDP2014) is the first publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2013. It consists of two parts: (1) a compilation of digital data for more than 200 trace

  9. Using Drosophila for Studies of Intermediate Filaments.

    Science.gov (United States)

    Bohnekamp, Jens; Cryderman, Diane E; Thiemann, Dylan A; Magin, Thomas M; Wallrath, Lori L

    2016-01-01

    Drosophila melanogaster is a useful organism for determining protein function and modeling human disease. Drosophila offers a rapid generation time and an abundance of genomic resources and genetic tools. Conservation in protein structure, signaling pathways, and developmental processes make studies performed in Drosophila relevant to other species, including humans. Drosophila models have been generated for neurodegenerative diseases, muscular dystrophy, cancer, and many other disorders. Recently, intermediate filament protein diseases have been modeled in Drosophila. These models have revealed novel mechanisms of pathology, illuminated potential new routes of therapy, and make whole organism compound screens feasible. The goal of this chapter is to outline steps to study intermediate filament function and model intermediate filament-associated diseases in Drosophila. The steps are general and can be applied to study the function of almost any protein. The protocols outlined here are for both the novice and experienced Drosophila researcher, allowing the rich developmental and cell biology that Drosophila offers to be applied to studies of intermediate filaments.

  10. C and C* among intermediate rings

    NARCIS (Netherlands)

    J. Sack; S. Watson

    2013-01-01

    Given a completely regular Hausdorff space X, an intermediate ring A(X) is a ring of real valued continuous functions between C*(X) and C(X). We discuss two correspondences between ideals in A(X) and z-filters on X, both reviewing old results and introducing new results. One correspondence, ZA, exte

  11. Synthesis of the key intermediate of ramelteon

    Institute of Scientific and Technical Information of China (English)

    Shan Bao Yu; Hao Min Liu; Yu Luo; Wei Lu

    2011-01-01

    Asymmetric conjugated addition of allylcopper reagents derived from an allyl Grignard reagent and CuBr·Me2S to chiral α,β-unsaturated N-acyl oxazolidinones has been achieved. The synthetic procedure was applied to the preparation of the key intermediate of the novel nonbenzodiazepine hypnotic drug, ramelteon.

  12. What Should be Taught in Intermediate Macroeconomics?

    Science.gov (United States)

    de Araujo, Pedro; O'Sullivan, Roisin; Simpson, Nicole B.

    2013-01-01

    A lack of consensus remains on what should form the theoretical core of the undergraduate intermediate macroeconomic course. In determining how to deal with the Keynesian/classical divide, instructors must decide whether to follow the modern approach of building macroeconomic relationships from micro foundations, or to use the traditional approach…

  13. Moroccan Arabic Intermediate Reader, Part II.

    Science.gov (United States)

    Alami, Wali A.; Hodge, Carlton T., Ed.

    The first section of this companion volume to "Moroccan Arabic Intermediate Reader, Part I" (AL 002 041) presents the Arabic script version of the pre-drills in Lessons IA-IIB in that volume. The second and major section comprises 20 lessons consisting of pre-drills, texts, notes, and questions. All material in this volume appears in Arabic script…

  14. Software Testing An ISEB Intermediate Certificate

    CERN Document Server

    Hambling, Brian

    2009-01-01

    Covering testing fundamentals, reviews, testing and risk, test management and test analysis, this book helps newly qualified software testers to learn the skills and techniques to take them to the next level. Written by leading authors in the field, this is the only official textbook of the ISEB Intermediate Certificate in Software Testing.

  15. Financial intermediation and the monetary transmission mechanism

    OpenAIRE

    Iris Claus; Christie Smith

    1999-01-01

    The article explores the role of financial intermediation in the monetary transmission mechanism. It discusses how and why shocks that affect lenders' willingness to lend can have an impact on economic activity, and why this needs to be factored into analyses of the interaction of monetary policy, the financial sector and the real economy.

  16. Simplifying biochemical models with intermediate species

    DEFF Research Database (Denmark)

    Feliu, Elisenda; Wiuf, Carsten

    2013-01-01

    canonical model that characterizes crucial dynamical properties, such as mono- and multistationarity and stability of steady states, of all models in the class. We show that if the core model does not have conservation laws, then the introduction of intermediates does not change the steady...

  17. Multiphase Gas in Intermediate Redshift Galaxies

    CERN Document Server

    Churchill, C W; Charlton, J; Januzzi, B; Churchill, Chris; Mellon, Rick; Charlton, Jane

    2000-01-01

    We present 40 quasar absorption line systems at intermediate redshifts (z~1), with focus on one of the most kinematically complex known, as examples of how the unique capabilities of space-based and ground-based facilities can be combined to glean much broader insights into astrophysical systems.

  18. A new intermediate in the Prins reaction

    Directory of Open Access Journals (Sweden)

    Shinichi Yamabe

    2013-03-01

    Full Text Available Two Prins reactions were investigated by the use of DFT calculations. A model composed of R–CH=CH2 + H3O+(H2O13 + (H2C=O2, R = Me and Ph, was adopted to trace reaction paths. For both alkenes, the concerted path forming 1,3-diols was obtained as the rate determining step (TS1. TS stands for a transition state. From the 1,3-diol, a bimolecular elimination (TS2 leads to the allylic alcohol as the first channel. In the second channel, the 1,3-diol was converted via TS3 into an unprecedented hemiacetal intermediate, HO–CH2–O–CH(R–CH2–CH2–OH. This intermediate undergoes ring closure (TS4, affording the 1,3-dioxane product. The intermediate is of almost the same stability as the product, and two species were suggested to be in a state of equilibrium. While the geometry of TS1 appears to be forwarded to that of a carbocation intermediate, the cation disappeared through the enlargement of the water cluster. Dynamical calculations of a classical trajectory using the atom-centered density matrix propagation molecular dynamics model on the four TSs were carried out, and results of IRC calculations were confirmed by them.

  19. Intermediality and politics in theatre and performance

    NARCIS (Netherlands)

    G.S. Dapp

    2013-01-01

    This dissertation applies the concepts of intermediality and politics to five performances by Rimini Protokoll, Christoph Schlingensief, and Igneous, and analyzes the implications that emerge on both a significational and a theoretical level. Based on the specific mediality involved, it argues that

  20. Teaching Vocabulary and Morphology in Intermediate Grades

    Science.gov (United States)

    Palumbo, Anthony; Kramer-Vida, Louisa; Hunt, Carolyn V.

    2015-01-01

    Direct vocabulary instruction of Tier 2 and Tier 3 words in intermediate-grade curricula is an important tool of literacy instruction because English is a language grafted from many roots and has not developed a one-to-one phoneme-grapheme correspondence. In addition to knowing graphemes and phonemes, students must formally learn words that cross…

  1. Trusted intermediating agents in electronic trade networks

    NARCIS (Netherlands)

    Klos, T.B.; Alkemade, F.

    2005-01-01

    Electronic commerce and trading of information goods significantly impact the role of intermediaries: consumers can bypass intermediating agents by forming direct links to producers. One reason that traditional intermediaries can still make a profit, is that they have more knowledge of the market, s

  2. Changes to the Intermediate Accounting Course Sequence

    Science.gov (United States)

    Davidson, Lesley H.; Francisco, William H.

    2009-01-01

    There is an ever-growing amount of information that must be covered in Intermediate Accounting courses. Due to recent accounting standards and the implementation of IFRS this trend is likely to continue. This report incorporates the results of a recent survey to examine the trend of spending more course time to cover this additional material.…

  3. Financial Intermediation, Monetary Uncertainty, and Bank Interest Margins Financial Intermediation, Monetary Uncertainty, and Bank Interest Margins

    OpenAIRE

    Leonardo Hernández

    1992-01-01

    Financial Intermediation, Monetary Uncertainty, and Bank Interest Margins This paper studies a simple model of financial intermediation in order to understand how the lending-borrowing spread or interest margin) charged by financial intermediaries is determined in equilibrium in a monetary economy. The main conclusion of the paper concerns the effect on the spread of changes in the distribution of monetary innovations. Thus, changes in the monetary-policy-rule followed by the Central Bank whi...

  4. The Swinburne intermediate-latitude pulsar survey

    Science.gov (United States)

    Edwards, R. T.; Bailes, M.; van Straten, W.; Britton, M. C.

    2001-09-01

    We have conducted a survey of intermediate Galactic latitudes using the 13-beam 21-cm multibeam receiver of the Parkes 64-m radio telescope. The survey covered the region enclosed by 5°Swinburne workstation cluster resulted in the detection of 170 pulsars of which 69 were new discoveries. Eight of the new pulsars, by virtue of their small spin periods and period derivatives, may be recycled and have been reported elsewhere. The slow pulsars discovered are typical of those already known in the volume searched, being of intermediate to old age. Several pulsars experience pulse nulling and two display very regular drifting subpulses. We discuss the new discoveries and provide timing parameters for the 48 slow pulsars for which we have a phase-connected solution.

  5. Intermediate filaments in small configuration spaces.

    Science.gov (United States)

    Nöding, Bernd; Köster, Sarah

    2012-02-24

    Intermediate filaments play a key role in cell mechanics. Apart from their great importance from a biomedical point of view, they also act as a very suitable micrometer-sized model system for semiflexible polymers. We perform a statistical analysis of the thermal fluctuations of individual filaments confined in microchannels. The small channel width and the resulting deflections at the walls give rise to a reduction of the configuration space by about 2 orders of magnitude. This circumstance enables us to precisely measure the intrinsic persistence length of vimentin intermediate filaments and to show that they behave as ideal wormlike chains; we observe that small fluctuations in perpendicular planes decouple. Furthermore, the inclusion of results for confined actin filaments demonstrates that the Odijk confinement regime is valid over at least 1 order of magnitude in persistence length. PMID:22463576

  6. Evolutionary Characteristics of China's Intermediate Manufactures

    Institute of Scientific and Technical Information of China (English)

    Minsung Kang; Jeong-Dong Lee

    2007-01-01

    China's economic development is characterized by progressive integration with international production chains as an assembly producer. Japan and South Korea are the major partners providing intermediate products to China. The present paper analyzes the Chinese intermediate sector's present condition and evolutionary characteristics revealed in bilateral trade with Japan and South Korea. The analysis uses the framework of new trade theory represented by "intra-industry trade". Trade statistics from 1997 to 2004 are analyzed using the database published by the OECD. Results show that China's inter-industrial evolution is characterized by its expanding positioning in the manner of the flying geese development paradigm of Asian countries. Furthermore, intra-industrial evolution is characterized by a concentration on price competitiveness. The framework and results of the industrial analysis presented in this paper assist in the understanding of China's manufacturing evolution and of the policy-making decisions taken in the process.

  7. Is TW Pictoris really an intermediate polar?

    CERN Document Server

    Norton, A J

    1998-01-01

    We present the results of a long ROSAT HRI observation of the candidate intermediate polar TW Pic. The power spectrum shows no sign of either the previously proposed white dwarf spin period or the proposed binary orbital period (1.996 hr and 6.06 hr respectively). The limits to the X-ray modulation are less than 0.3% in each case. In the absence of a coherent X-ray pulsation, the credentials of TW Pic for membership of the intermediate polar subclass must be suspect. We further suggest that the true orbital period of the binary may be the shorter of the two previously suggested, and that the longer period may represent a quasi-periodic phenomenon associated with the accretion disc.

  8. Entropy of Intermediate-Mass Black Holes

    OpenAIRE

    Frampton, Paul H.

    2009-01-01

    Observational searches for Intermediate-Mass Black Holes (IMBHs), defined to have masses between 30 and 300,000 solar masses, provide limits which allow up to ten percent of what is presently identified as halo dark matter to be in the form of IMBHs. These concentrate entropy so efficiently that the halo contribution can be bigger than the core supermassive black hole. Formation of IMBHs is briefly discussed.

  9. Desperately Seeking Intermediate-Mass Black Holes

    OpenAIRE

    Frampton, Paul H.

    2009-01-01

    Observational searches for Intermediate Mass Black Holes (IMBHs), defined to have masses between 30 and 300,000 solar masses, provide limits which allow up to ten percent of what is presently identified as halo dark matter to be in the form of IMBHs. These concentrate entropy so efficiently that the halo contribution can be bigger than the core supermassive black hole. Formation of IMBHs is briefly discussed.

  10. Ruthenium Vinyl Carbene Intermediates in Enyne Metathesis

    OpenAIRE

    Diver, Steven T.

    2007-01-01

    This review provides an overview of ruthenium vinyl carbene reactivity as it relates to enyne metathesis. Methods for the synthesis of metathesis-active and metathesis-inactive complexes are also summarized. Some of the early hypotheses about vinyl carbene intermediates in enyne metatheses were tested in the arena of synthetic chemistry and subsequently led to mechanistic studies. In these two areas, studies from the author's labs are described. There are still many unresolved questions in en...

  11. International express student's book : pre-intermediate

    CERN Document Server

    Taylor, Liz

    1996-01-01

    The New Edition of International Express Pre-Intermediate retains all the keys features of this popular and successel four-level course. It combines engaging, up-to-date topics with a time-efficient and student-centred approach to language work, and clearly focused activities that reflect learner's real communicative needs - the ideal course for professional adults who use English for work, travel, and socializing.

  12. Mobile phones in conflicts of financial intermediation

    OpenAIRE

    Asongu, Simplice A; Tchamyou, Vanessa S.

    2015-01-01

    To the best our knowledge, in the first empirical macroeconomic examination of the nexus between financial intermediation and mobile phones, Asongu employs two conflicting financial system definitions in the assessment of how mobile phones have stimulated financial development in Africa. Within the framework of the dominant International Monetary Fund's International Financial Statistics (2008) definition, mobile phones are established to be negatively associated with financial intermediary d...

  13. Mobile Phones in Conflicts of Financial Intermediation

    OpenAIRE

    Asongu, Simplice; Tchamyou, Vanessa

    2015-01-01

    To the best our knowledge, in the first empirical macroeconomic examination of the nexus between financial intermediation and mobile phones, Asongu employs two conflicting financial system definitions in the assessment of how mobile phones have stimulated financial development in Africa. Within the framework of the dominant International Monetary Fund’s International Financial Statistics (2008) definition, mobile phones are established to be negatively associated with financial intermediary d...

  14. Leveraging Efforts on Remittances and Financial Intermediation

    OpenAIRE

    Manuel Orozco; Rachel Fedewa

    2006-01-01

    This report seeks to analyze the efforts among financial institutions to leverage the relationship between financial intermediation and remittance transfers. The impact of family remittances has been highlighted in the literature as an important one for development. A development impact is one that addresses issues relating to the distribution of wealth and overall improvements in the quality of people's lives. More recently, policy recommendations have stressed the importance of linking remi...

  15. An Idealized View of Financial Intermediation

    OpenAIRE

    Sissoko, Carolyn

    2007-01-01

    Using the monetary model developed in Sissoko (2007), where the general equilibrium assumption that every agent buys and sells simultaneously is relaxed, we observe that in this environment fiat money can implement a Pareto optimum only if taxes are type-specific. We then consider intermediated money by assuming that financial intermediaries whose liabilities circulate as money have an important identifying characteristic: they are widely viewed as default-free. The paper demonstrates that de...

  16. Financial intermediation and the rights offer paradox

    OpenAIRE

    Koenig-Matsoukis, Laure

    2010-01-01

    In this study, we investigate the trading dynamics around rights issues. We employ signed and unsigned trading activity measures in order to provide evidence of costly financial intermediation. We, first, document short selling activity by underwriters and shareholders during rights issues leading to significant negative abnormal returns during the offer. Further, we provide evidence that rights tend to be sold below their fair value. Our results, therefore, suggest that the lack of use of ri...

  17. FIRM - A Graph-Based Intermediate Representation

    OpenAIRE

    Braun, Matthias; Buchwald, Sebastian; Zwinkau, Andreas

    2011-01-01

    We present our compiler intermediate representation Firm. Programs are always in SSA-form enabling a representation as graphs. We argue that this naturally encodes context information simplifying many analyses and optimizations. Instructions are connected by dependency edges relaxing the total to a partial order inside a basic block. For example alias analysis results can be directly encoded in the graph structure. The paper gives an overview of the representation and focuses on its construct...

  18. Far from the intermediate nuclear field

    International Nuclear Information System (INIS)

    Pairing correlations in nuclear physics; the BCS state and quasi-particles; the layer model; collision effects on nuclear dynamics; the theory of cluster formation (application to nucleus fragmentation); short range correlations (few-particle systems); deuterium electron scattering; dibaryonic resonances; traditional and exotic hadron probes of nuclear structure; spectral fluctuations and chaotic motion; corrections to the intermediate nuclear field (nonrelativistic and other effects); and heavy nuclei splitting and nuclear superfluidity are introduced

  19. Interest Based Financial Intermediation: Analysis and Solutions

    OpenAIRE

    Shaikh, Salman

    2012-01-01

    Interest is prohibited in all monotheist religions. Apart from religion, interest is also regarded as unjust price of money capital by pioneer secular philosophers as well as some renowned economists. However, it is argued by some economists that modern day, market driven interest rate in a competitive financial market is different from usury and that the interest based financial intermediation has served a useful purpose in allocation of resources as well as in allocation of risk, given the ...

  20. Intermediate Trainee Perspectives of Family Therapy Skills

    OpenAIRE

    Benson, Margo

    2004-01-01

    Marriage and family therapy training involves the development of therapy skills that lead to effective treatment, and the family therapy literature recognizes the importance of skill development in training. The training literature dealing with specific skills most often refers to beginning-level skills and obtains data largely from supervisors and trainers. Intermediate-level skills appear to be overlooked and no apparent attention is given from the perspective of trainees. This research ...

  1. UEP LT Codes with Intermediate Feedback

    DEFF Research Database (Denmark)

    Sørensen, Jesper Hemming; Popovski, Petar; Østergaard, Jan

    2013-01-01

    We analyze a class of rateless codes, called Luby transform (LT) codes with unequal error protection (UEP). We show that while these codes successfully provide UEP, there is a significant price in terms of redundancy in the lower prioritized segments. We propose a modification with a single inter...... intermediate feedback message. Our analysis shows a dramatic improvement on the decoding performance of the lower prioritized segment....

  2. Intermediates in Isotopic Exchange Reactions Involving Diborane

    International Nuclear Information System (INIS)

    By conventional mass spectrometric analysis, the self-exchange reaction of diborane was studied by using boron and hydrogen isotopes as tracers. The ratio of deuterium to boron exchange was found to be 2.8. This suggests that the reaction is not completely proceeding by exchange of BH3's as an entity, and that the mechanism is more complicated than simply a stripping reaction between diborane and a borane. It was therefore decided to attempt to get some knowledge of the intermediates that are present in diborane dissociation since they may shed light on the mechanism of the exchange. Using a specially constructed mass spectrometer of high sensitivity coupled with a flow reactor, it was possible to make a direct detection of the intermediate involved in the diborane equilibria. The intermediates BH3 and BH2 were found to be present and their ionization potentials were measured. In addition, a small amount of B3Hn was observed but the value of n could not be determined because of the weak peaks obtained. An attempt is made to interpret the self-exchange reaction of diborane in terms of these intermediates. The results suggest that diborane is in rapid equilibrium with borane (BH3). In addition, apparently diborane can also dissociate in BH2 which was about twice as abundant as BH3. The B3Hn intermediate that was observed is believed to arise from the reaction. BH3 + B2H6 -> B3H9. In applying this information to the isotopic self-exchange in diborane, it appears that the exchange cannot be going by a stripping mechanism such as BD3 + BH3 - BH3 - BD3 - BH3 + BH3, since the deuterium-to-boron isotopic ratio then should be 3. Another possible mechanism of exchange is BD3 + B2H6 ⇌ B3D3H6; the B3 complex can be pictured as a symmetrical one. If the bonds were all exactly equivalent the D/ 10B ratio would statistically become 3; however, some isotope effect may be present in the fragmentation of the complex and the ratio could deviate from 3. Another possible way in which

  3. SOME ASPECTS REGARDING MEANING OF INTERMEDIATE MANAGEMENT BALANCES

    Directory of Open Access Journals (Sweden)

    ILIE RĂSCOLEAN

    2014-10-01

    Full Text Available This paper presents some aspects regarding intermediate management balances as a pay instrument of production factors and financing future activities. Paper debate intermediate management balances determination and interpretation.

  4. Intermediate Temperature Solid Oxide Fuel Cell Development

    Energy Technology Data Exchange (ETDEWEB)

    S. Elangovan; Scott Barnett; Sossina Haile

    2008-06-30

    Solid oxide fuel cells (SOFCs) are high efficiency energy conversion devices. Present materials set, using yttria stabilized zirconia (YSZ) electrolyte, limit the cell operating temperatures to 800 C or higher. It has become increasingly evident however that lowering the operating temperature would provide a more expeditious route to commercialization. The advantages of intermediate temperature (600 to 800 C) operation are related to both economic and materials issues. Lower operating temperature allows the use of low cost materials for the balance of plant and limits degradation arising from materials interactions. When the SOFC operating temperature is in the range of 600 to 700 C, it is also possible to partially reform hydrocarbon fuels within the stack providing additional system cost savings by reducing the air preheat heat-exchanger and blower size. The promise of Sr and Mg doped lanthanum gallate (LSGM) electrolyte materials, based on their high ionic conductivity and oxygen transference number at the intermediate temperature is well recognized. The focus of the present project was two-fold: (a) Identify a cell fabrication technique to achieve the benefits of lanthanum gallate material, and (b) Investigate alternative cathode materials that demonstrate low cathode polarization losses at the intermediate temperature. A porous matrix supported, thin film cell configuration was fabricated. The electrode material precursor was infiltrated into the porous matrix and the counter electrode was screen printed. Both anode and cathode infiltration produced high performance cells. Comparison of the two approaches showed that an infiltrated cathode cells may have advantages in high fuel utilization operations. Two new cathode materials were evaluated. Northwestern University investigated LSGM-ceria composite cathode while Caltech evaluated Ba-Sr-Co-Fe (BSCF) based pervoskite cathode. Both cathode materials showed lower polarization losses at temperatures as low as 600

  5. Intermediate depth seismicity - a reflection seismic approach

    Science.gov (United States)

    Haberland, C.; Rietbrock, A.

    2004-12-01

    During subduction the descending oceanic lithosphere is subject to metamorphic reactions, some of them associated with the release of fluids. It is now widely accepted, that these reactions and associated dehydration processes are directly related with the generation of intermediate depth earthquakes (dehydration embrittlement). However, the structure of the layered oceanic plate at depth and the location of the earthquakes relative to structural units of the subducting plate (sources within the oceanic crust and/or in the upper oceanic mantle lithosphere?) are still not resolved yet. This is in mainly due to the fact that the observational resolution needed to address these topics (in the range of only a few kilometers) is hardly achieved in field experiments and related studies. Here we study the wavefields of intermediate depth earthquakes typically observed by temporary networks in order to assess their high-resolution potential in resolving structure of the down going slab and locus of seismicity. In particular we study whether the subducted oceanic Moho can be detected by the analysis of secondary phases of local earthquakes (near vertical reflection). Due to the irregular geometry of sources and receivers we apply an imaging technique similar to diffraction stack migration. The method is tested using synthetic data both based on 2-D finite difference simulations and 3-D kinematic ray tracing. The accuracy of the hypocenter location and onset times crucial for the successful application of stacking techniques (coherency) was achieved by the use of relatively relocated intermediate depth seismicity. Additionally, we simulate the propagation of the wavefields at larger distance (wide angle) indicating the development of guided waves traveling in the low-velocity waveguide associated with the modeled oceanic crust. We also present application on local earthquake data from the South American subduction zone.

  6. Levantamento malacológico em parques urbanos de Belo Horizonte, Minas Gerais, Brasil

    Directory of Open Access Journals (Sweden)

    Carlos Tito Guimarães

    1997-04-01

    Full Text Available Existem atualmente na região metropolitana de Belo Horizonte 18 parques urbanos (também denominados "parques ecológicos" com coleções hídricas (lagoas, nascentes, córregos etc. Pesquisas iniciais em 17 destes parques mostraram a ocorrência de moluscos hospedeiros intermediários do Schistosoma mansoni em pelo menos quatro deles. Capturas mensais nestes parques, de agosto/94 a fevereiro/96, mostraram os seguintes resultados em relação aos planorbíneos: Parque Julien Rien: 1.145 exemplares de Biomphalaria glabrata (2 mm a 13 mm; Parque Betânia: 149 exemplares de B. glabrata (4 mm a 13 mm; Parque Santa Lúcia: 2.431 exemplares de B. straminea (3 mm a 9 mm e Parque Lagoa do Nado: três exemplares de B. tenagophila (3 mm a 10 mm. As visitas aos parques terão prosseguimento e, após um diagnóstico sobre a situação de cada parque, serão sugeridas às autoridades municipais medidas de controle e/ou erradicação adequadas a cada área.

  7. Levantamento malacológico em parques urbanos de Belo Horizonte, Minas Gerais, Brasil

    Directory of Open Access Journals (Sweden)

    Guimarães Carlos Tito

    1997-01-01

    Full Text Available Existem atualmente na região metropolitana de Belo Horizonte 18 parques urbanos (também denominados "parques ecológicos" com coleções hídricas (lagoas, nascentes, córregos etc. Pesquisas iniciais em 17 destes parques mostraram a ocorrência de moluscos hospedeiros intermediários do Schistosoma mansoni em pelo menos quatro deles. Capturas mensais nestes parques, de agosto/94 a fevereiro/96, mostraram os seguintes resultados em relação aos planorbíneos: Parque Julien Rien: 1.145 exemplares de Biomphalaria glabrata (2 mm a 13 mm; Parque Betânia: 149 exemplares de B. glabrata (4 mm a 13 mm; Parque Santa Lúcia: 2.431 exemplares de B. straminea (3 mm a 9 mm e Parque Lagoa do Nado: três exemplares de B. tenagophila (3 mm a 10 mm. As visitas aos parques terão prosseguimento e, após um diagnóstico sobre a situação de cada parque, serão sugeridas às autoridades municipais medidas de controle e/ou erradicação adequadas a cada área.

  8. THEORIES REGARDING FINANCIAL INTERMEDIATION AND FINANCIAL INTERMEDIARIES – A SURVEY

    OpenAIRE

    2009-01-01

    In this paper we propose to make a presentation of the main theories on financial intermediation and financial intermediaries. Modern theory of financial intermediation examine the main functions of financial intermediation, how the financial intermediation affect the economy as a whole and the effects of government policies on financial intermediaries. We will focus on issues of function of financial intermediaries, such as reduction of transaction costs, liquidity provision, information pro...

  9. Financial Intermediation, Variability and the Development Process

    OpenAIRE

    Carranza, L. (Luis); Galdón-Sánchez, J.E. (José E.)

    2002-01-01

    In this paper we build a model of financial intermediation that explains the GDP variability pattern of an economy during the development process. We find evidence that per capita output is more volatile in middle-income economies than in both low and high-income economies. We show that, if the model economy is in the early or in the mature stages of development, there is a unique equilibrium. However, in the middle stages of development, multi-ple equilibria arise. Moreover, we find that in ...

  10. The intermediate age open cluster NGC 2660

    CERN Document Server

    Sandrelli, S; Tosi, M P; Marconi, G

    1999-01-01

    We present CCD UBVI photometry of the intermediate old open cluster NGC2660, covering from the red giants region to about seven magnitudes below the main sequence turn-off. Using the synthetic Colour - Magnitude Diagram method, we estimate in a self-consistent way values for distance modulus ((m-M)0 ~= 12.2), reddening (E(B-V) ~= 0.40), metallicity ([Fe/H] about solar), and age (age ~ 1 Gyr). A 30% population of binary stars turns out to be probably present.

  11. The aftermath of the intermediate value theorem

    Directory of Open Access Journals (Sweden)

    Morales Claudio H

    2004-01-01

    Full Text Available The solvability of nonlinear equations has awakened great interest among mathematicians for a number of centuries, perhaps as early as the Babylonian culture (3000–300 B.C.E.. However, we intend to bring to our attention that some of the problems studied nowadays appear to be amazingly related to the time of Bolzano's era (1781–1848. Indeed, this Czech mathematician or perhaps philosopher has rigorously proven what is known today as the intermediate value theorem, a result that is intimately related to various classical theorems that will be discussed throughout this work.

  12. The aftermath of the intermediate value theorem

    Directory of Open Access Journals (Sweden)

    Claudio H. Morales

    2004-08-01

    Full Text Available The solvability of nonlinear equations has awakened great interest among mathematicians for a number of centuries, perhaps as early as the Babylonian culture (3000–300 B.C.E.. However, we intend to bring to our attention that some of the problems studied nowadays appear to be amazingly related to the time of Bolzano's era (1781–1848. Indeed, this Czech mathematician or perhaps philosopher has rigorously proven what is known today as the intermediate value theorem, a result that is intimately related to various classical theorems that will be discussed throughout this work.

  13. Thermoelectric power generator with intermediate loop

    Science.gov (United States)

    Bell, Lon E; Crane, Douglas Todd

    2013-05-21

    A thermoelectric power generator is disclosed for use to generate electrical power from heat, typically waste heat. An intermediate heat transfer loop forms a part of the system to permit added control and adjustability in the system. This allows the thermoelectric power generator to more effectively and efficiently generate power in the face of dynamically varying temperatures and heat flux conditions, such as where the heat source is the exhaust of an automobile, or any other heat source with dynamic temperature and heat flux conditions.

  14. Observational constraints on dual intermediate inflation

    CERN Document Server

    Barrow, John D; Magueijo, João

    2014-01-01

    We explore the observational implications of models of intermediate inflation driven by modified dispersion relations, specifically those representing the phenomenon of dimensional reduction in the ultraviolet limit. These models are distinct from the standard ones because they do not require violations of the strong energy condition, and this is reflected in their structure formation properties. We find that they can naturally accommodate deviations from exact scale-invariance. They also make clear predictions for the running of the spectral index and tensor modes, rendering the models straightforwardly falsifiable. We discuss the observational prospects for these models and the implications these may have for quantum gravity scenarios.

  15. Ligand Intermediates in Metal-Catalyzed Reactions

    Energy Technology Data Exchange (ETDEWEB)

    Gladysz, John A.

    1999-07-31

    The longest-running goal of this project has been the synthesis, isolation, and physical chemical characterization of homogeneous transition metal complexes containing ligand types believed to be intermediates in the metal-catalyzed conversion of CO/H{sub 2}, CO{sub 2}, CH{sub 4}, and similar raw materials to organic fuels, feedstocks, etc. In the current project period, complexes that contain unusual new types of C{sub x}(carbide) and C{sub x}O{sub y} (carbon oxide) ligands have been emphasized. A new program in homogeneous fluorous phase catalysis has been launched as described in the final report.

  16. q-Gamow States for intermediate energies

    CERN Document Server

    Plastino, A; Zamora, D J

    2016-01-01

    In a recent paper [Nuc. Phys. A {\\bf 948}, (2016) 19] we have demonstrated the possible existence of Tsallis' q-Gamow states. Now, accelerators' experimental evidence for Tsallis' distributions has been ascertained only at very high energies. Here, instead, we develop a different set of q-Gamow states for which the associated q-Breit-Wigner distribution could easily be found at intermediate energies, for which accelerators are available at many locations. In this context, it should be strongly emphasized [Physica A {\\bf 388} (2009) 601] that, empirically, one never exactly and unambiguously "detects" pure Gaussians, but rather q-Gaussians. A prediction is made via Eq.(3.30)

  17. Double photoionization of He at intermediate energies

    International Nuclear Information System (INIS)

    The ratio of double-to-single ionization of He has been measured between 280 and 1210 eV to investigate its behavior in this partially unexplored region. These measurements, compared with the most recent theories of Pan and Kelly (private communication) and of Hino, show the importance of including not only ground state but also final state correlations, in contrast to the high-energy behavior discussed by Dalgarno and Sadeghpour where consideration of final-state correlations proves inessential. The author's intermediate-energy results also appear to indicate the importance of including higher-order effects in the theory

  18. Intermediate Bandgap Solar Cells From Nanostructured Silicon

    Energy Technology Data Exchange (ETDEWEB)

    Black, Marcie [Bandgap Engineering, Lincoln, MA (United States)

    2014-10-30

    This project aimed to demonstrate increased electronic coupling in silicon nanostructures relative to bulk silicon for the purpose of making high efficiency intermediate bandgap solar cells using silicon. To this end, we formed nanowires with controlled crystallographic orientation, small diameter, <111> sidewall faceting, and passivated surfaces to modify the electronic band structure in silicon by breaking down the symmetry of the crystal lattice. We grew and tested these silicon nanowires with <110>-growth axes, which is an orientation that should produce the coupling enhancement.

  19. [Intermediate energy nuclear physics]: Technical progress report

    International Nuclear Information System (INIS)

    This report summarizes work carried out between October 1, 1987 and August 1, 1988 at the Nuclear Physics Laboratory of the University of Colorado, Boulder, under Contract DE-FG02-86ER40269 with the United States Department of Energy. The contract supports experimental work in intermediate energy nuclear physics. The experimental program is very broadly based, ranging from pion-nucleon studies at TRIUMF, to inelastic pion scattering and charge exchange reactions at LAMPF, to nucleon charge exchange at LAMPF/WNR and to electron scattering at NIKHEF. In addition, a number of other topics related to accelerator physics are described in this report

  20. Intermediate form of osteopetrosis with recessive inheritance

    Energy Technology Data Exchange (ETDEWEB)

    Kaibara, N.; Katsuki, I.; Hotokebuchi, T.; Takagishi, K.

    1982-11-01

    The clinical and radiographic features of the intermediate form of osteopetrosis in two sibs are presented in which the disorder appears to have been inherited as a recessive trait. Although this form of osteopetrosis has been poorly delineated, its recognition is practically important in order to give an accurate prognosis. This paper also presents an unusual complication of bilateral avascular necrosis of the femoral head in the younger sib. Radiographic changes of the femoral heads suggest those of Legg-Calve-Perthes disease, though the possibility of avascular necrosis following unrecognized femoral neck fracture is not completely excluded.

  1. The discovery of the intermediate vector bosons

    International Nuclear Information System (INIS)

    The discovery of the intermediate vector bosons in 1983 at CERN marked the culmination of a long effort to unify the theory of weak and electromagnetic forces. Here a brief outline of development of the electroweak theory which unifies these forces is given first. Its essential feature is the prediction of the existence of the W+- and Z0 bosons with rest masses of about ninety times the proton mass and lifetimes around 10-24s. Then the experimental methods used at CERN to produce and to detect these very massive and short-lived particles are described. (author)

  2. Dicty_cDB: Contig-U03225-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 3163 ) Biomphalaria glabrata chromosome UNK clone BG_BBa... 50 0.054 6 ( CO733545 ) SlLT02c06a08f1 squirrel ... 0.079 18 ( CO738531 ) SlLE04c20l23f1 squirrel embryo library 1 Spermoph... 40 0.

  3. Molluscicidal saponins from Phytolacca dodecandra

    DEFF Research Database (Denmark)

    Thiilborg, S. T.; Christensen, S. B.; Cornett, Claus;

    1993-01-01

    -beta-D-xylopyranosyl-(1-->6)-O-beta-D-gluco-pyranosyl-(1-->3)]-beta -D-glucopyranosyloleanolic acid mainly by spectroscopic methods (LSIMS, H-1 NMR, COSY, NOESY, TOCSY, J-resolved H-1 NMR, C-13 NMR, HETCOR). The saponins are potent molluscicides against the schistosomiasis transmitting snail Biomphalaria glabrata with LC...

  4. The molluscicidal activity of coumarins from Ethulia conyzoides and of dicumarol

    DEFF Research Database (Denmark)

    Kady, M M; Brimer, L; Furu, P;

    1992-01-01

    The molluscicidal principles of Ethulia conyzoides were identified as ethuliacoumarin A (1) and isoethuliacoumarin A (2). Ethuliacoumarin A possessed an LC90 between 19 and 23.5 ppm depending on the age of the snail against Biomphalaria glabrata, and between 12 and 15 ppm against Bulinus truncatu....... In contrast, the coumarin anticoagulant warfarin (3) did not show molluscicidal activity....

  5. Relação entre a patogenicidade do Schistosoma mansoni em camundongos e a susceptibilidade do molusco vetor: III. Mortalidade, pesos corporal e das vísceras Relationship between the pathogenicity of Schistosoma mansoni in mice and the susceptibility of the vector mollusc: III. Mortality, body weight and viscera weights

    Directory of Open Access Journals (Sweden)

    Eliana Maria Zanotti-Magalhães

    1995-08-01

    Full Text Available Estudou-se a relação entre o desenvolvimento da hepatomegalia, da esplenomegalia, peso corporal e taxa de mortalidade em camundongos experimentalmente infectados por Schistosoma mansoni com o grau de susceptibilidade de Biomphalaria glahrata e B. tenagophila nas quais se desenvolveram as cercárias infectantes respectivamente, das linhagens BH e SJ. Foram utilizados como hospedeiro definitivo camundongos Swiss, SPF e como hospedeiros intermediários populações de moluscos selecionados geneticamente para o caráter susceptibilidade. Foram observados menores pesos corporais e das visceras em camundongos infectados com cercárias provenientes de moluscos que apresentaram elevado grau de susceptibilidade. A maior susceptibilidade dos moluscos à infecção pelo S. mansoni correspondeu a uma menor sobrevivência dos camundongos infectados. Os resultados fazem crer que a maior adaptação do parasita ao hospedeiro intermediário, traduzidos pelas taxas mais elevadas de susceptibilidade, pode levar a um comportamento diferente deste parasita no hospedeiro definitivo.The relationship between the development of hepatomegaly, splenomegaly, body weight and mortality rate and the degree of susceptibility of Biomphalaria glabrata and B. tenagophila at which infective cercariae developed was studied. The study utilized Swiss mice, SPF, as definitive hosts and populations of snails genetically selected for character susceptibility as intermediate hosts. Low body weight and smaller viscera were observed in infected mice with cercariae originating from snails that showed a high degree of susceptibility. The higher susceptibility of molluscs infected with S. mansoni corresponded to a lower survival of the infected mice. These results lead to the conclusion that the higher degree of adaptation of the parasite to its intermediate hosts, evidenced by the high indexes of susceptibility, leads to different behaviour on the part of this parasite in its definitive

  6. 22 CFR 140.10 - Intermediate credit institutions.

    Science.gov (United States)

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Intermediate credit institutions. 140.10... TRAFFICKERS Enforcement § 140.10 Intermediate credit institutions. (a) Treatment as non-governmental entity or as a foreign government entity. Intermediate credit institutions (“ICIs”) shall be subject to...

  7. Surface Intermediate Zone of Submerged Turbulent Buoyant Jet in Current

    DEFF Research Database (Denmark)

    Chen, H. B.; Larsen, Torben

    1995-01-01

    This paper deals with the intermediate zone between the jet and plume stages of a submerged buoyant discharge from sea outfall in current. The stability criteria, plume width and height after the intermediate zone and the dilution within the intermediate region have been studied theoretically...

  8. Intermediate product selection and blending in the food processing industry

    DEFF Research Database (Denmark)

    Kilic, Onur A.; Akkerman, Renzo; van Donk, Dirk Pieter;

    2013-01-01

    This study addresses a capacitated intermediate product selection and blending problem typical for two-stage production systems in the food processing industry. The problem involves the selection of a set of intermediates and end-product recipes characterising how those selected intermediates...

  9. Financial Intermediation, Monetary Uncertainty, and Bank Interest Margins Financial Intermediation, Monetary Uncertainty, and Bank Interest Margins

    Directory of Open Access Journals (Sweden)

    Leonardo Hernández

    1992-03-01

    Full Text Available Financial Intermediation, Monetary Uncertainty, and Bank Interest Margins This paper studies a simple model of financial intermediation in order to understand how the lending-borrowing spread or interest margin charged by financial intermediaries is determined in equilibrium in a monetary economy. The main conclusion of the paper concerns the effect on the spread of changes in the distribution of monetary innovations. Thus, changes in the monetary-policy-rule followed by the Central Bank which alter the volatility of inflation will have important effects on the interest margin and also on the amount of credit available to investors. A crosssection empirical analysis strongly supports our hypothesis:

  10. Fission in intermediate energy heavy ion reactions

    Energy Technology Data Exchange (ETDEWEB)

    Wilhelmy, J.B.; Begemann-Blaich, M.; Blaich, T.; Boissevain, J.; Fowler, M.M.; Gavron, A.; Jacak, B.V.; Lysaght, P.S. (Los Alamos National Lab., NM (USA)); Britt, H.C.; Fields, D.J.; Hansen, L.F.; Lanier, R.G.; Massoletti, D.J.; Namboodiri, M.M.; Remington, B.A.; Sangster, T.C.; Struble, G.L.; Webb, M.L. (Lawrence Livermore National Lab., CA (USA)); Chan, Y.D.; Dacai, A.; Harmon, A.; Leyba, J.; Pouliot, J.; Stokstad, R.G. (Lawrence Berkeley Lab., CA (USA)); Hansen, O.; Levine, M.J.; Thorn, C.E.; Trautmann, W. (Brookhaven National Lab., Upton, NY (USA)); Dichter, B.; Kaufman, S.; Videbaek, F. (Argonne National Lab. (USA)); Fraenkel, Z.; Mamane, G. (Weizmann Inst. of Science, Rehovoth (Israel)); Cebra, D.; Westfall, G.D. (Michigan State Univ., East Lansing (USA))

    1989-10-09

    A systematic study of reaction mechanisms at intermediate energies (50-100 MeV/A) has been performed at the Lawrence Berkeley Laboratory's BeValac using medium weight projectiles on medium and heavy element targets. A gas and plastic phoswich detector system was employed which gave large geometric coverage and a wide dynamic response. The particles identified with the gas detectors could be characterized into three components - intermediate mass fragments (IMF), fission fragments (FF) and heavy residues (HR). Major observed features are: The reaction yields are similar in the 50 to 100 MeV/A range, central collisions have high multiplicty of IMF's with broad angular correlations consistent with a large participant region, effects of final state Coulomb interactions are observed and give information on the size and temporal behavior of the source, true fission yields are dependent on target fissility and correlated with relatively peripheral collisions. Analysis of fission and evaporation yields implies limiting conditions for which fission decay remains a viable deexcitation channel. (orig.).

  11. Intermediate-field transport of contaminants

    International Nuclear Information System (INIS)

    This report is about ''intermediate-field'' transport or the migration of contaminants from arrays of discrete waste packages or sources. In constructing nuclear waste repositories in rock, it may be necessary to place a waste package across a rock fracture, or a rock fracture may develop some time after waste packages have been emplaced. To predict the spatial and temporal distribution of contaminant species from a line of waste packages facing a rock fracture may be important, because such fractures may now be considered a preferential pathway for released radionuclides to re-enter the biosphere. In land disposal of hazardous wastes, individual barrels may contain especially toxic material whose dispersion special attention. We have published analytic solutions for the multidimensional advective transport of contaminants from arrays of waste packages and multiple areal sources into a planar fracture. The results show a near region in which the concentrations vary greatly in the direction transverse to ground-water flow, an intermediate region in which the array can be treated as an infinite plane source of dissolving species, and a far-field region in which the array can be treated as a plane source of finite extent. The array equations have been developed for both porous and fractured media. In this paper we summarize and compare the work with multiple areal sources facing a planar fracture and an array of point sources in porous media. 5 refs., 5 figs

  12. BANKING INTERMEDIATION AND CONSEQUENCES OF FINANCIAL CRISIS

    Directory of Open Access Journals (Sweden)

    Medar Lucian-Ion

    2012-12-01

    Full Text Available The financial intermediation of bank institutions, has an essential role in mobilising of the available funds and their distribution in various products and services, for economic growth. The extent that banking system is in distress or passing through a period of crisis, then, everything turns into a general crisis, especially that, in some states, natural and legal persons have been learned ,,to live’’ on the credits.The effectiveness of banking intermediation activity in Romania depends on how fast the market is enabled under the influence of the new European regulations. The Romanian market in all its forms is the second largest in the EU, and the banking system is almost entirely made up of banks with foreign capital. The romanian banking market has not suffered so much because of the financial crisis. To the extent that banking institutions provide the necessary funds, Romania has important resources for the transition to a new economic cycle based on sustainable development.

  13. Reactivity of surface carbonaceous intermediates. Doctoral thesis

    Energy Technology Data Exchange (ETDEWEB)

    Koerts, T.

    1992-06-19

    The study has concentrated on two reactions both related with carbon-carbon bond formation on transition metal catalysts. The first concerns the influences of a vanadium promoter on the kinetics of elementary reaction steps upon synthesis gas conversion on a rhodium catalyst. The second is related to the general problem of initiating a carbon-carbon bond between two methane molecules. Both reactions occur via reactive C1 surface intermediates. These surface species were created from CO and CH4 respectively. Mainly transient kinetic techniques were used which were combined with some quantum chemical calculations. The influence of a vanadium promoter on the formation and intrinsic reactivity of CHx species adsorbed on rhodium catalysts, for hydrogenation, chaingrowth and CO insertion, has also been investigated. On rhodium catalysts a very reactive C1 intermediate was found to be formed from dissociative CO adsorption. The formation of the surface species was found to be enhanced by vanadium promotion, which lowers the activation energy for CO dissociation.

  14. Fluorescence and bioluminescence of bacterial luciferase intermediates

    International Nuclear Information System (INIS)

    An intermediate in the luciferase-catalyzed bioluminescent oxidation of FMNH2, isolated and purified by chromatography at --200, was postulated to be an oxygenated reduced flavine-luciferase. Maintained and studied at --20 to --300, this material exhibits a relatively weak fluorescence emission peaking at about 505 nm when excited at 370 nm. It may comprise more than one species. Upon continued exposure to light at 370 nm, the intensity of this fluorescence increases, often by a factor of 5 or more, and its emission spectrum is blue shifted to a maximum at about 485 nm. Upon warming this fluorescence is lost and the fluorescence of flavine mononucleotide appears. If warming is carried out in the presence of a long chain aldehyde, bioluminescence occurs, with the appearance of a similar amount of flavine fluorescence. The bioluminescence yield is about the same with irradiated and nonirradiated samples. The bioluminescence emission spectrum corresponds exactly to the fluorescence emission spectrum of the intermediate formed by irradiation, implicating the latter as being structurally close to the emitting species in bioluminescence. (auth)

  15. Latex of "Coroa de Cristo" (Euphorbia Splendens: an effective molluscicide

    Directory of Open Access Journals (Sweden)

    Maurício C. de Vasconcelos

    1986-12-01

    Full Text Available An aqueous solution of the latex of "coroa de cristo" (Euphorbia splendens var. hislopii showed molluscicide action (LD90 at a concentration lower than 0.5 ppm on Biomphalaria glabrata and B. tenagophila reared in laboratory and at a concentration lower than 4.0 ppm for field B. tenagophila.Foi estudada em laboratório a atividade moluscicida do látex da "coroa de cristo" (Euphorbia splendens var. hislopii. A planta apresentou ação moluscicida (DL90 a uma concentração inferior de 0,5ppm para Biomphalaria glabrata e Biomphalaria tenagophila de laboratório e inferior a 4ppm para caramuhos de campo.

  16. Lab-scale preparations of Candida albicans and dual Candida albicans-Candida glabrata biofilms on the surface of medical-grade polyvinyl chloride (PVC) perfusion tube using a modified gravity-supported free-flow biofilm incubator (GS-FFBI).

    Science.gov (United States)

    Shao, Jing; Lu, KeQiao; Tian, Ge; Cui, YanYan; Yan, YuanYuan; Wang, TianMing; Zhang, XinLong; Wang, ChangZhong

    2015-02-01

    The assembly of a man-made gravity-supported free-flow biofilm incubator (GS-FFBI) was described, which was composed of a gas cushion injector and four incubators. The GS-FFBI had the characteristics of (i) a bottom-up flow direction, and (ii) lab-scale biofilm preparation without the use of a multichannel pump. Two opportunistic fungal strains, namely Candida albicans and Candida glabrata, were employed to incubate C. albicans and dual C. albicans-C. glabrata biofilms on the surface of medical-grade polyvinyl chloride perfusion tube. In terms of the results from {2, 3-bis (2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide} (XTT) assay, dry weight measurement, colony-forming unit counting, susceptibility test, and scanning electron microscopy, it was demonstrated that GS-FFBI could form both stable single and dual Candida biofilms with no significant variations among the four incubators or the three daily incubations within 21h, and could operate for at least 96h smoothly with no contamination of stock medium. The results also indicated, for the first time, that C. albicans and C. glabrata might be co-existent competitively and symbiotically in the dual biofilms with flowing media. GS-FFBI would be a useful device to study in vitro morphological and physiological features of microbial biofilms in the medical settings.

  17. Turned Back: Mad Men as Intermedial Melodrama

    Directory of Open Access Journals (Sweden)

    Monique Rooney

    2012-09-01

    Full Text Available This essay draws on definitions of gesture (Giorgio Agamben and Peter Brooks and catachresis (Peter Brooks, Jacques Derrida to examine the primacy of non-verbal signifiers as communicators of meaning in AMC’s Mad Men. Beginning with an analysis of Mad Men’s credit sequence, it draws attention to Mad Men’s use of gesture and catachresis in relation to melodrama’s privileging of non-verbal and naturalistic expression and its persistence as an intermedial mode that has moved back and forth between various media (theatre, novel, cinema, television and now digital formats. It argues that Mad Men’s melodramatic aesthetic is one that obliquely, and via a gestural and rhetorical ‘turned back’, communicates its relation to the past and the present.

  18. Fission dynamics with systems of intermediate fissility

    Indian Academy of Sciences (India)

    E Vardaci; A Di Nitto; P N Nadtochy; A Brondi; G La Rana; R Moro; M Cinausero; G Prete; N Gelli; E M Kozulin; G N Knyazheva; I M Itkis

    2015-08-01

    A 4 light charged particle spectrometer, called 8 LP, is in operation at the Laboratori Nazionali di Legnaro, Italy, for studying reaction mechanisms in low-energy heavy-ion reactions. Besides about 300 telescopes to detect light charged particles, the spectrometer is also equipped with an anular PPAC system to detect evaporation residues and a two-arm time-of-flight spectrometer to detect fission fragments. The spectrometer has been used in several fission dynamics studies using as a probe light charged particles in the fission and evaporation residues (ER) channels. This paper proposes a journey within some open questions about the fission dynamics and a review of the main results concerning nuclear dissipation and fission time-scale obtained from several of these studies. In particular, the advantages of using systems of intermediate fissility will be discussed.

  19. Opening the Black Box of Intermediation

    DEFF Research Database (Denmark)

    Nowinska, Agnieszka

    shipping companies with customers, regulatory authorities and suppliers. So far only fragmented information is available on the general value creation strategies of these intermediaries and their behaviour towards the environmental pressures, with the main contributions stressing competitive pressures...... dynamics. This paper draws on qualitative data originating with interviews with industry representatives and can also be regarded as a preliminary approach to a broader project. The analysis distinguishes between relational capital at the intrafirm level (the network among the company's employees......) and at the interfirm level (between partners and within alliances and associations).The tentative results show that both of these levels are important in defining the intermediating firms' business models and in answering their environmental threats and in building up competitive advantage. The paper ends with a short...

  20. Kinetic advantage of controlled intermediate nuclear fusion

    Science.gov (United States)

    Guo, Xiaoming

    2012-09-01

    The dominated process of controlled fusion is to let nuclei gain enough kinetic energy to overcome Coulomb barrier. As a result, a fusion scheme can consider two factors in its design: to increase kinetic energy of nuclei and to alter the Coulomb barrier. Cold Fusion and Hot fusion are all one-factor schemes while Intermediate Fusion is a twofactors scheme. This made CINF kinetically superior. Cold Fusion reduces deuteron-deuteron distance, addressing Coulomb barrier, and Hot Fusion heat up plasma into extreme high temperature, addressing kinetic energy. Without enough kinetic energy made Cold Fusion skeptical. Extreme high temperature made Hot Fusion very difficult to engineer. Because CIFN addresses both factors, CIFN is a more promising technique to be industrialized.

  1. Flow angle from intermediate mass fragment measurements

    Energy Technology Data Exchange (ETDEWEB)

    Rami, F.; Crochet, P.; Dona, R.; De Schauenburg, B.; Wagner, P.; Alard, J.P.; Andronic, A.; Basrak, Z.; Bastid, N.; Belyaev, I.; Bendarag, A.; Berek, G.; Best, D.; Caplar, R.; Devismes, A.; Dupieux, P.; Dzelalija, M.; Eskef, M.; Fodor, Z.; Gobbi, A.; Grishkin, Y.; Herrmann, N.; Hildenbrand, K.D.; Hong, B.; Kecskemeti, J.; Kirejczyk, M.; Korolija, M.; Kotte, R.; Lebedev, A.; Leifels, Y.; Merlitz, H.; Mohren, S.; Moisa, D.; Neubert, W.; Pelte, D.; Petrovici, M.; Pinkenburg, C.; Plettner, C.; Reisdorf, W.; Schuell, D.; Seres, Z.; Sikora, B.; Simion, V.; Siwek-Wilczynska, K.; Stoicea, G.; Stockmeir, M.; Vasiliev, M.; Wisniewski, K.; Wohlfarth, D.; Yushmanov, I.; Zhilin, A

    1999-02-15

    Directed sideward flow of light charged particles and intermediate mass fragments was measured in different symmetric reactions at bombarding energies from 90 to 800 A MeV. The flow parameter is found to increase with the charge of the detected fragment up to Z = 3-4 and then turns into saturation for heavier fragments. Guided by simple simulations of an anisotropic expanding thermal source, we show that the value at saturation can provide a good estimate of the flow angle, {theta}{sub flow}, in the participant region. It is found that {theta}{sub flow} depends strongly on the impact parameter. The excitation function of {theta}{sub flow} reveals striking deviations from the ideal hydrodynamical scaling. The data exhibit a steep rise of {theta}{sub flow} to a maximum at around 250 - 400 A MeV, followed by a moderate decrease as the bombarding energy increases further.

  2. Simulations of Oligomeric Intermediates in Prion Diseases

    CERN Document Server

    Mobley, D L; Singh, R R P; Kulkarni, R V; Slepoy, A; Mobley, David L.; Cox, Daniel L.; Singh, Rajiv R. P.; Kulkarni, Rahul V.; Slepoy, Alexander

    2003-01-01

    We extend our previous stochastic cellular automata based model for areal aggregation of prion proteins on neuronal surfaces. The new anisotropic model allow us to simulate both strong beta-sheet and weaker attachment bonds between proteins. Constraining binding directions allows us to generate aggregate structures with the hexagonal lattice symmetry found in recently observed in vitro experiments. We argue that these constraints on rules may correspond to underlying steric constraints on the aggregation process. We find that monomer dominated growth of the areal aggregate is too slow to account for some observed doubling time-to-incubation time ratios inferred from data, and so consider aggregation dominated by relatively stable but non-infectious oligomeric intermediates. We compare a kinetic theory analysis of oligomeric aggregation to spatially explicit simulations of the process. We find that with suitable rules for misfolding of oligomers, possibly due to water exclusion by the surrounding aggregate, th...

  3. Intermediate inflation driven by DBI scalar field

    Science.gov (United States)

    Nazavari, N.; Mohammadi, A.; Ossoulian, Z.; Saaidi, Kh.

    2016-06-01

    Picking out a DBI scalar field as inflation, the slow-rolling inflationary scenario is studied by attributing an exponential time function to scale factor, known as intermediate inflation. The perturbation parameters of the model are estimated numerically for two different cases, and the final result is compared with Planck data. The diagram of tensor-to-scalar ratio r versus scalar spectra index ns is illustrated, and it is found that they are within an acceptable range as suggested by Planck. In addition, the acquired values for amplitude of scalar perturbation reveal the ability of the model to depict a good picture of the Universe in one of its earliest stages. As a further argument, the non-Gaussianity is investigated, displaying that the model prediction stands in a 68% C.L. regime according to the latest Planck data.

  4. Melting of metallic intermediate level waste

    Energy Technology Data Exchange (ETDEWEB)

    Huutoniemi, Tommi; Larsson, Arne; Blank, Eva [Studsvik Nuclear AB, Nykoeping (Sweden)

    2013-08-15

    This report presents a feasibility study of a melting facility for core components and reactor internals. An overview is given of how such a facility for treatment of intermediate level waste might be designed, constructed and operated and highlights both the possibilities and challenges. A cost estimate and a risk analysis are presented in order to make a conclusion of the technical feasibility of such a facility. Based on the authors' experience in operating a low level waste melting facility, their conclusion is that without technical improvements such a facility is not feasible today. This is based on the cost of constructing and operating such a facility, in conjunction with the radiological risks associated with operation and the uncertain benefits to disposal and long term safety.

  5. [Intermediate care units and noninvasive ventilation].

    Science.gov (United States)

    Becker, Heinrich F; Schönhofer, Bernd; Vogelmeier, Claus

    2006-04-15

    Intermediate care units (IMC) have been introduced to provide optimal patient management according to disease severity and to bridge the gap between intensive care (ICU) and general wards. Most patients that are referred to an IMC need monitoring and intensive analgetic treatment. Over the past years noninvasive ventilation (NIV) and weaning have emerged as important new forms of active treatment in the IMC. Most studies that have been published so far demonstrate that an IMC improves patient outcome and lowers costs, although randomized controlled trials are missing. NIV reduces mortality, the need for intubation as well as ICU and hospital length of stay in patients with chronic obstructive pulmonary disease (COPD) and other disorders that cause respiratory failure. In many cases NIV can be performed in the IMC, a fact that reduces the number of ICU admissions, lowers costs and improves patient care. The high prevalence of pulmonary diseases and NIV emphasizes the importance of pneumologists as directors of both ICU and IMC.

  6. Precalibrating an intermediate complexity climate model

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Neil R. [The Open University, Earth and Environmental Sciences, Milton Keynes (United Kingdom); Cameron, David [Centre for Ecology and Hydrology, Edinburgh (United Kingdom); Rougier, Jonathan [University of Bristol, Department of Mathematics, Bristol (United Kingdom)

    2011-10-15

    Credible climate predictions require a rational quantification of uncertainty, but full Bayesian calibration requires detailed estimates of prior probability distributions and covariances, which are difficult to obtain in practice. We describe a simplified procedure, termed precalibration, which provides an approximate quantification of uncertainty in climate prediction, and requires only that uncontroversially implausible values of certain inputs and outputs are identified. The method is applied to intermediate-complexity model simulations of the Atlantic meridional overturning circulation (AMOC) and confirms the existence of a cliff-edge catastrophe in freshwater-forcing input space. When uncertainty in 14 further parameters is taken into account, an implausible, AMOC-off, region remains as a robust feature of the model dynamics, but its location is found to depend strongly on values of the other parameters. (orig.)

  7. Intermediate thinnings as a source of energywood

    Energy Technology Data Exchange (ETDEWEB)

    Sammallahti, K.; Laespae, O.; Nurmi, J. (Finnish Forest Research Inst., Kannus (Finland)), e-mail: kati.sammallahti@metla.fi, e-mail: otto.laspa@metla.fi, e-mail: juha.nurmi@metla.fi

    2010-07-01

    During 2008 and 2009 10 hectares of spruce stand was harvested with an energy wood method and 3,8 hectares with a conventional method. Average DBH was 21 cm, length 19 m and the number of stems per hectare was 674. The harvester productivity was in this study 10 % higher with the conventional method (36,2 m3 / ha) than with the energy wood method (32,6 m3 / ha). The second part of the study consisted baling with a Timberjack 1490D residue baler on an intermediate thinning. In 2008 residues were baled from a total area of 8,7 hectares. Total yield was 218 bales and yield per hectare was 26 bales. Yield per hour was 19,7 bales and the average time consumption per bale was 3,18 minutes. (orig.)

  8. Connectomic intermediate phenotypes for psychiatric disorders

    Directory of Open Access Journals (Sweden)

    Alex eFornito

    2012-04-01

    Full Text Available Psychiatric disorders are phenotypically heterogeneous entities with a complex genetic basis. To mitigate this complexity, many investigators study so-called intermediate phenotypes that putatively provide a more direct index of the physiological effects of candidate genetic risk variants than overt psychiatric syndromes. Magnetic resonance imaging (MRI is a particularly popular technique for measuring such phenotypes because it allows interrogation of diverse aspects of brain structure and function in vivo. Much of this work however, has focused on relatively simple measures that quantify variations in the physiology or tissue integrity of specific brain regions in isolation, contradicting an emerging consensus that most major psychiatric disorders do not arise from isolated dysfunction in one or a few brain regions, but rather from disturbed interactions within and between distributed neural circuits; i.e., they are disorders of brain connectivity. The recent proliferation of new MRI techniques for comprehensively mapping the entire connectivity architecture of the brain, termed the human connectome, has provided a rich repertoire of tools for understanding how genetic variants implicated in mental disorder impact distinct neural circuits. In this article, we review research using these connectomic techniques to understand how genetic variation influences the connectivity and topology of human brain networks. We highlight recent evidence from twin and imaging genetics studies suggesting that the penetrance of candidate risk variants for mental illness, such as those in SLC6A4, MAOA, ZNF804A and APOE, may be higher for intermediate phenotypes characterised at the level of distributed neural systems than at the level of spatially localised brain regions. The findings indicate that imaging connectomics provides a powerful framework for understanding how genetic risk for psychiatric disease is expressed through altered structure and function of

  9. Intermediate Ethanol Blends Catalyst Durability Program

    Energy Technology Data Exchange (ETDEWEB)

    West, Brian H; Sluder, Scott; Knoll, Keith; Orban, John; Feng, Jingyu

    2012-02-01

    In the summer of 2007, the U.S. Department of Energy (DOE) initiated a test program to evaluate the potential impacts of intermediate ethanol blends (also known as mid-level blends) on legacy vehicles and other engines. The purpose of the test program was to develop information important to assessing the viability of using intermediate blends as a contributor to meeting national goals for the use of renewable fuels. Through a wide range of experimental activities, DOE is evaluating the effects of E15 and E20 - gasoline blended with 15% and 20% ethanol - on tailpipe and evaporative emissions, catalyst and engine durability, vehicle driveability, engine operability, and vehicle and engine materials. This report provides the results of the catalyst durability study, a substantial part of the overall test program. Results from additional projects will be reported separately. The principal purpose of the catalyst durability study was to investigate the effects of adding up to 20% ethanol to gasoline on the durability of catalysts and other aspects of the emissions control systems of vehicles. Section 1 provides further information about the purpose and context of the study. Section 2 describes the experimental approach for the test program, including vehicle selection, aging and emissions test cycle, fuel selection, and data handling and analysis. Section 3 summarizes the effects of the ethanol blends on emissions and fuel economy of the test vehicles. Section 4 summarizes notable unscheduled maintenance and testing issues experienced during the program. The appendixes provide additional detail about the statistical models used in the analysis, detailed statistical analyses, and detailed vehicle specifications.

  10. Covalent functionalization of graphene with reactive intermediates.

    Science.gov (United States)

    Park, Jaehyeung; Yan, Mingdi

    2013-01-15

    Graphene, a material made exclusively of sp(2) carbon atoms with its π electrons delocalized over the entire 2D network, is somewhat chemically inert. Covalent functionalization can enhance graphene's properties including opening its band gap, tuning conductivity, and improving solubility and stability. Covalent functionalization of pristine graphene typically requires reactive species that can form covalent adducts with the sp(2) carbon structures in graphene. In this Account, we describe graphene functionalization reactions using reactive intermediates of radicals, nitrenes, carbenes, and arynes. These reactive species covalently modify graphene through free radical addition, CH insertion, or cycloaddition reactions. Free radical additions are among the most common reaction, and these radicals can be generated from diazonium salts and benzoyl peroxide. Electron transfer from graphene to aryl diazonium ion or photoactivation of benzoyl peroxide yields aryl radicals that subsequently add to graphene to form covalent adducts. Nitrenes, electron-deficient species generated by thermal or photochemical activation of organic azides, can functionalize graphene very efficiently. Because perfluorophenyl nitrenes show enhanced bimolecular reactions compared with alkyl or phenyl nitrenes, perfluorophenyl azides are especially effective. Carbenes are used less frequently than nitrenes, but they undergo CH insertion and C═C cycloaddition reactions with graphene. In addition, arynes can serve as a dienophile in a Diels-Alder type reaction with graphene. Further study is needed to understand and exploit the chemistry of graphene. The generation of highly reactive intermediates in these reactions leads to side products that complicate the product composition and analysis. Fundamental questions remain about the reactivity and regioselectivity of graphene. The differences in the basal plane and the undercoordinated edges of graphene and the zigzag versus arm-chair configurations

  11. 藁杆双脐螺在中国内陆的分布现状与传病风险%Distribution and schistosomiasis transmission risks of Biomphalaria stra-minea in inland China

    Institute of Scientific and Technical Information of China (English)

    黄少玉; 张启明; 李晓恒; 邓卓晖

    2014-01-01

    藁杆双脐螺可作为曼氏血吸虫中间宿主,1981年证实在深圳市局部地区有该螺孳生;2013年再次调查发现,该螺已在深圳市、以及周边的东莞市和惠州市等地大范围蔓延扩散,并已在当地形成较优势种群,有进一步扩散的趋势。由于深圳市及周边地区与国际交流密切,劳务输出等人口流动性大,且目前我国由境外输入的曼氏血吸虫病病例报道亦逐渐增多,因此曼氏血吸虫病在我国传播或流行的潜在风险因素正在逐步增加,必须引起高度重视,及早采取相应的防控措施,加强监测,降低该病在我国传播或流行的风险。本文就藁杆双脐螺在中国内陆的发现、分布、扩散蔓延及传病风险等进行了综述,并提出相关的防控建议。%Biomphalaria straminea,the intermediary host of Schistosoma mansoni,was found by survey in local areas of Shen-zhen City in 1981,which was the first finding of the snail in inland China. By 2013,the snail had spread in large range of Shen-zhen City and overspread to the surrounding regions,Dongguan City and Huizhou City. Due to the facts that Shenzhen City has many international communications and is a key area of labor export,with high population mobility,while the reports of S. manso-ni infection in the returnees of our country from Africa have been increasing recently,it must be paid a high attention to whether the epidemic or transmission of schistosomiasis mansoni may happen under the present circumstance. This paper initially discusses the finding,distribution,spreading and overspreading and transmission risk of B. straminea in inland China and puts forward some related control suggestions.

  12. Schistosoma mansoni mucin gene (SmPoMuc expression: epigenetic control to shape adaptation to a new host.

    Directory of Open Access Journals (Sweden)

    Cecile Perrin

    Full Text Available The digenetic trematode Schistosoma mansoni is a human parasite that uses the mollusc Biomphalaria glabrata as intermediate host. Specific S. mansoni strains can infect efficiently only certain B. glabrata strains (compatible strain while others are incompatible. Strain-specific differences in transcription of a conserved family of polymorphic mucins (SmPoMucs in S. mansoni are the principle determinants for this compatibility. In the present study, we investigated the bases of the control of SmPoMuc expression that evolved to evade B. glabrata diversified antigen recognition molecules. We compared the DNA sequences and chromatin structure of SmPoMuc promoters of two S. mansoni strains that are either compatible (C or incompatible (IC with a reference snail host. We reveal that although sequence differences are observed between active promoter regions of SmPoMuc genes, the sequences of the promoters are not diverse and are conserved between IC and C strains, suggesting that genetics alone cannot explain the evolution of compatibility polymorphism. In contrast, promoters carry epigenetic marks that are significantly different between the C and IC strains. Moreover, we show that modifications of the structure of the chromatin of the parasite modify transcription of SmPoMuc in the IC strain compared to the C strain and correlate with the presence of additional combinations of SmPoMuc transcripts only observed in the IC phenotype. Our results indicate that transcription polymorphism of a gene family that is responsible for an important adaptive trait of the parasite is epigenetically encoded. These strain-specific epigenetic marks are heritable, but can change while the underlying genetic information remains stable. This suggests that epigenetic changes may be important for the early steps in the adaptation of pathogens to new hosts, and might be an initial step in adaptive evolution in general.

  13. 光滑念珠菌临床分离株对氟康唑耐药的分子机制%Molecular mechanisms of fluconazole resistance in clinical isolates of Candida glabrata

    Institute of Scientific and Technical Information of China (English)

    沈银忠; 卢洪洲; 张永信

    2010-01-01

    目的 明确光滑念珠菌临床分离株对氟康唑耐药的主要分子机制.方法 采用实时荧光定量RT.PCR技术对光滑念珠菌临床分离株ERG11、CDR1和CDR2基因表达的mRNA进行相对定量,比较氟康唑耐药株与敏感株基因表达水平的差异.结果 在光滑念珠菌氟康唑耐药株、剂量依赖性敏感株及敏感株中,ERG11基因mRNA相对表达量分别为:121.4±96.8、102.9±78.8、51.2±20.7:CDR1基因mRNA相对表达量分别为:3.1±1.4、1.9±0.7、1.1±0.4;CDR2基因mRNA相对表达量分别为:3.7±2.2、3.4±2.4、1.9±0.9.耐药株ERGll基因mRNA表达量高于敏感株(P=0.041);耐药株(P<0.001)和剂量依赖性敏感株(P=0.009)CDR1基因mRNA表达量均高于敏感株;耐药株CDR2基因mRNA表达量高于敏感株(P=0.018).随着光滑念珠菌对氟康唑敏感性的降低,ERG11、CDR1及CDR2基因mRNA的表达量均不同程度上升.结论 ERG11、CDR1及CDR2基因mRNA的上调表达与光滑念珠菌临床分离株对氟康唑的耐药性有关,ERG11、CDR1及CDR2基因上调表达是光滑念珠菌临床分离株对氟康唑耐药的主要分子机制.%Objective To determine if changes in the levels of expression of ERG11, CDR1 and CDR2 genes could be associated with resistance phenotype in clinical isolates of Candida glbrata (C. glabrata). Methods We used quantitative RT-PCR analysis to evaluate the expression of the ERG11, CDR1 and CDR2 genes in clinical isolates including 9 fluconazole-resistant, 9 flueonazole-susceptible dose dependent (S-DD) and 10 fluconazole-sensitive C glabrata isolates. Results In the fluconazole-resistant isolates. The S-DD isolates and the fluconazole-sensitive isolates, the levels of expression of ERG11 gene were 21.4±96.8, 102.9±78.8, 51.2±20.7, respectively; the levels of expression of CDR1 gene were 3.1±1.4, 1.9±0.7,1.1±0.4, respectively; the levels of expression of CDR2 gene were 3.7±2.2,3.4±2.4,1.9±0.9, respectively. Quantitative RT-PCR analyses revealed

  14. Possible Source of Intermediate Ions over Marine Environment

    OpenAIRE

    Sunil D. Pawar; V. Gopalakrishnan

    2012-01-01

    Measurements of small, intermediate and large ions made onboard ORV Sagarkanya over the Arabian Sea in May-June 2003 during Arabian Sea Monsoon Experiment (ARMEX) are reported here. The daily averaged values of small-, intermediate-, and large-ion concentrations measured for 36 days during this cruise have been used for analysis. The analysis shows a weak positive correlation of 0.14 between intermediate- and large-ion concentrations, which indicates that the sources of these two types of ion...

  15. Taxation of Financial Intermediation Activities in Hong Kong

    OpenAIRE

    Jack M. Mintz; Stephen R. Richardson

    2001-01-01

    This paper discusses issues related to the taxation of financial intermediation in Hong Kong in the context of Hong Kong's position as a major regional financial centre. It first provides some background analysis as to the definition of financial intermediation and identification of the providers of financial services. This is then followed by a discussion of the principles of taxation applicable to financial intermediation, including a comparison of income taxes to consumption taxes. Some sp...

  16. Tests of Financial Intermediation and Banking Reform in China.

    OpenAIRE

    Park, Albert; Sehrt, Kaja

    2001-01-01

    We develop tests of financial intermediation by national banking systems based on the expectation that, in commercial systems, financial intermediation should not be overly influenced by policy variables; should be greater in richer, faster growing industrial areas; and should direct funds to the best projects regardless of where deposits originate. Using Chinese provincial data from 1991 to 1997, we test whether financial reforms in the mid-1990s increased efficient intermediation by differe...

  17. Financial Intermediation in Muslim Community: Issues and Problems

    OpenAIRE

    Alomar, Ibrahim

    2006-01-01

    It is widely known that Muslim society inherited an interest based financial intermediation system from others instead of developing their own banking system. However, Muslim Economists and scholars around the world made efforts to have and develop their own financial intermediation since there was no initial working model to act upon, except the belief that interest-based financial intermediation might be replaced by an Islamic one on the basis of profit-and loss sharing. During the last f...

  18. Financial Intermediation and Economic Growth of Jordan 1964-1988

    OpenAIRE

    Magableh, Ali H.

    1995-01-01

    Until recently, the economics and financial literature placed little attention on the role that financial intermediation can play in accelerating the rate of economic development in less Developed Countries (LDCs). This has been changed now, however, where some instrumental role has been emphasised for financial intermediation in the process of economic development and growth. It is argued that an expansion of the financial system, size and intermediation in LDCs tends to increase the level o...

  19. Efficient short step synthesis of Corey's tamiflu intermediate.

    Science.gov (United States)

    Kipassa, Nsiama Tienabe; Okamura, Hiroaki; Kina, Kengo; Hamada, Toshiyuki; Iwagawa, Tetsuo

    2008-03-01

    Corey's tamiflu intermediate was synthesized from a bicyclolactam adduct obtained by base-catalyzed Diels-Alder reaction of N-nosyl-3-hydroxy-2-pyridone with ethyl acrylate. A compound that has the same array of functional groups with the Corey's intermediate was obtained in four steps from the DA adduct in 47% overall yield. The intermediate itself was also prepared efficiently by simply changing the protective group.

  20. Structure and Mechanistic Implications of a Tryptophan Synthase Quinonoid Intermediate

    Energy Technology Data Exchange (ETDEWEB)

    Barends,T.; Domratcheva, T.; Kulik, V.; Blumenstein, L.; Niks, D.; Dunn, M.; Schlichting, I.

    2008-01-01

    Quinonoid intermediates play a key role in the catalytic mechanism of pyridoxal 5'-phosphate (PLP)-dependent enzymes. Whereas structures of other PLP-bound reaction intermediates have been determined, a high-quality structure of a quinonoid species has not been reported. We present the crystal structure of the indoline quinonoid intermediate of tryptophan synthase (see figure) and discuss its implications for the enzymatic mechanism and allosteric regulation.

  1. Structure Characterization of the Folding Intermediates of Proteins

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Although the native state and the fully unfolded state of proteins have been extensively studied, the folding pathway and intermediates in the protein folding process have not been thoroughly investigated.To understand the mechanisms of protein folding, the early intermediates in the protein folding process must be clearly characterized.The present paper is a mini review containing 20 references involving studies on folding intermediates of several proteins.

  2. Mechanical Properties of Intermediate Filament Proteins.

    Science.gov (United States)

    Charrier, Elisabeth E; Janmey, Paul A

    2016-01-01

    Purified intermediate filament (IF) proteins can be reassembled in vitro to produce polymers closely resembling those found in cells, and these filaments form viscoelastic gels. The cross-links holding IFs together in the network include specific bonds between polypeptides extending from the filament surface and ionic interactions mediated by divalent cations. IF networks exhibit striking nonlinear elasticity with stiffness, as quantified by shear modulus, increasing an order of magnitude as the networks are deformed to large strains resembling those that soft tissues undergo in vivo. Individual IFs can be stretched to more than two or three times their resting length without breaking. At least 10 different rheometric methods have been used to quantify the viscoelasticity of IF networks over a wide range of timescales and strain magnitudes. The mechanical roles of different classes of cytoplasmic IFs on mesenchymal and epithelial cells in culture have also been studied by an even wider range of microrheological methods. These studies have documented the effects on cell mechanics when IFs are genetically or pharmacologically disrupted or when normal or mutant IF proteins are exogenously expressed in cells. Consistent with in vitro rheology, the mechanical role of IFs is more apparent as cells are subjected to larger and more frequent deformations.

  3. Fluorine production in intermediate-mass stars

    CERN Document Server

    Mowlavi, N; Arnould, M

    1996-01-01

    The 19F production during the first dozen thermal pulses of AGB stars with (M=3,Z=0.02), (M=6,Z=0.02) and (M=3,Z=0.001) is investigated on grounds of detailed stellar models and of revised rates for 15N(a,g)19F and 18O(a,g)22Ne. These calculations confirm an early expectation that 19F {\\it is} produced in AGB thermal pulses. They also enlarge substantially these previous results by showing that the variations of the level of 19F production during the evolution is very sensitive to the maximum temperature reached at the base of the pulse. These variations are analyzed in detail, and are shown to result from a subtle balance between different nuclear effects (mainly 19F production or destruction in a pulse, and 15N synthesis during the interpulse), possibly super-imposed on dilution effects in more or less extended pulse convective tongues. Our calculations, as most others, do not predict the third dredge-up self- consistently. When parametrized, it appears that our models of intermediate-mass AGB stars are abl...

  4. Molecular phylogeny of metazoan intermediate filament proteins.

    Science.gov (United States)

    Erber, A; Riemer, D; Bovenschulte, M; Weber, K

    1998-12-01

    We have cloned cytoplasmic intermediate filament (IF) proteins from a large number of invertebrate phyla using cDNA probes, the monoclonal antibody IFA, peptide sequence information, and various RT-PCR procedures. Novel IF protein sequences reported here include the urochordata and nine protostomic phyla, i.e., Annelida, Brachiopoda, Chaetognatha, Echiura, Nematomorpha, Nemertea, Platyhelminthes, Phoronida, and Sipuncula. Taken together with the wealth of data on IF proteins of vertebrates and the results on IF proteins of Cephalochordata, Mollusca, Annelida, and Nematoda, two IF prototypes emerge. The L-type, which includes 35 sequences from 11 protostomic phyla, shares with the nuclear lamins the long version of the coil 1b subdomain and, in most cases, a homology segment of some 120 residues in the carboxyterminal tail domain. The S-type, which includes all four subfamilies (types I to IV) of vertebrate IF proteins, lacks 42 residues in the coil 1b subdomain and the carboxyterminal lamin homology segment. Since IF proteins from all three phyla of the chordates have the 42-residue deletion, this deletion arose in a progenitor prior to the divergence of the chordates into the urochordate, cephalochordate, and vertebrate lineages, possibly already at the origin of the deuterostomic branch. Four phyla recently placed into the protostomia on grounds of their 18S rDNA sequences (Brachiopoda, Nemertea, Phoronida, and Platyhelminthes) show IF proteins of the L-type and fit by sequence identity criteria into the lophotrochozoic branch of the protostomia. PMID:9847417

  5. Intrinsic Josephson Junctions with Intermediate Damping

    Science.gov (United States)

    Warburton, Paul A.; Saleem, Sajid; Fenton, Jon C.; Speller, Susie; Grovenor, Chris R. M.

    2011-03-01

    In cuprate superconductors, adjacent cuprate double-planes are intrinsically Josephson-coupled. For bias currents perpendicular to the planes, the current-voltage characteristics correspond to those of an array of underdamped Josephson junctions. We will discuss our experiments on sub-micron Tl-2212 intrinsic Josephson junctions (IJJs). The dynamics of the IJJs at the plasma frequency are moderately damped (Q ~ 8). This results in a number of counter-intuitive observations, including both a suppression of the effect of thermal fluctuations and a shift of the skewness of the switching current distributions from negative to positive as the temperature is increased. Simulations confirm that these phenomena result from repeated phase slips as the IJJ switches from the zero-voltage to the running state. We further show that increased dissipation counter-intuitively increases the maximum supercurrent in the intermediate damping regime (PRL vol. 103, art. no. 217002). We discuss the role of environmental dissipation on the dynamics and describe experiments with on-chip lumped-element passive components in order control the environment seen by the IJJs. Work supported by EPSRC.

  6. The RGB Sample of Intermediate BL Lacs

    CERN Document Server

    Laurent-Mühleisen, S A; Feigelson, E D; Brinkmann, W; Siebert, J

    1999-01-01

    Combining newly identified and previously known BL Lacs from the RASS-Green Bank (RGB) catalog, we present a sample of 127 BL Lacs, the largest ever derived from a single uniform survey. A Complete sample of 33 objects brighter than O=18.0 mag is also presented. These samples are compared to other known BL Lac samples and are generally found to exhibit properties intermediate between those of the previously disparate classes of High and Low energy peaked BL Lacs (HBLs and LBLs, respectively). This result is most dramatic in the distribution of the X-ray to radio logarithmic flux ratios, where the RGB BL Lacs are shown to peak precisely where the sharp dichotomy between the two subclasses was previously seen. The alpha_ro vs alpha_ox diagram also shows the RGB sample smoothly bridges the gap between the previously distinct subclasses of LBLs and HBLs. We also find a weak, but statistically significant correlation between the composite X-ray spectral index alpha_xox and alpha_ro. This implies that the more LBL-...

  7. [Intermediate/high energy nuclear physics

    International Nuclear Information System (INIS)

    We have continued to develop a theoretical framework for the quark and gluon structure of nuclei. Our approach features a successful phenomenological model, the quark cluster model (QCM), and an ambitious program in the non-perturbative solution of quantum field theories. The effort in quantum field theory provides theoretical results to test or replace assumed ingredients of the QCM. By the explicit example of a scalar field theory in 2D we have solved the long-standing problem of how to treat the dynamics of the vacuum in light-front quantization. We now propose to solve the same problem for simple Fermion field theories in 2D such as the Gross-Neveu model. We propose in subsequent years to address QCD in low dimensionality with the purpose of extracting non-perturbative predictions for quark and gluon amplitudes in few baryon systems. Simultaneously with this new effort we will continue to develop extensions and applications of the QCM. We propose to continue predicting phenomena to be observed in high energy particle-nucleus collisions that reflect the rearrangement of quarks and gluons in nuclei. We have completed our analysis of the SLAC E101 and E133 experiments on Deuterium to elucidate the degree to which a six-quark cluster contribution is admissable in the Bjorken x > 1 data. We have completed our development of a parameterized thermal liquid drop model for light nuclei. In addition we have completed a set of predictions for the formation of a ''nuclear stratosphere'' in nuclei created by intermediate energy heavy ion interactions. These results motivate a new investigation of the temperature dependence of the ion-ion potential with particular emphasis on the thermal dependence of the barrier height and radius. We have also shown that a consistent treatment of relativistic effects is important for a theoretical description of the elastic magnetic form factor of 17O. 85 refs

  8. Possible Source of Intermediate Ions over Marine Environment

    Directory of Open Access Journals (Sweden)

    Sunil D. Pawar

    2012-01-01

    Full Text Available Measurements of small, intermediate and large ions made onboard ORV Sagarkanya over the Arabian Sea in May-June 2003 during Arabian Sea Monsoon Experiment (ARMEX are reported here. The daily averaged values of small-, intermediate-, and large-ion concentrations measured for 36 days during this cruise have been used for analysis. The analysis shows a weak positive correlation of 0.14 between intermediate- and large-ion concentrations, which indicates that the sources of these two types of ions are different over ocean surface. The negative correlation is observed between small- and intermediate-ion concentration for entire period of cruise. In addition, it is seen that the intermediate-ion concentration shows a very good (=0.58 and significant positive correlation with sea surface pressure. Based on good negative correlation between small- and intermediate-ion concentrations and good positive correlation between intermediate-ion concentration and sea surface pressure, it has been proposed that attachment of small ions to the ultrafine particles transported from upper troposphere to marine boundary layer is the main source of intermediate ions over ocean surface. This study supports the idea that the main source of ultrafine particles over marine boundary layer (MBL is entrainment of aerosol particles from the free troposphere.

  9. An architecture for recycling intermediates in a column-store

    NARCIS (Netherlands)

    Ivanova, M.G.; Kersten, M.L.; Nes, N.J.; Goncalves, R.A.

    2010-01-01

    Automatic recycling intermediate results to improve both query response time and throughput is a grand challenge for state-of-the-art databases. Tuples are loaded and streamed through a tuple-at-a-time processing pipeline, avoiding materialisation of intermediates as much as possible. This limits th

  10. Surface intermediates on metal electrodes at high temperatures

    DEFF Research Database (Denmark)

    Zachau-Christiansen, Birgit; Jacobsen, Torben; Bay, Lasse;

    1998-01-01

    The mechanisms widely conceived for the O(2)-reduction or H(2)-oxidation reactions in SOFC's involve intermediate O/H species adsorbed on the electrode surface. The presence of these intermediates is investigated by linear sweep voltammetry. In air at moderate temperatures (500 degrees C) Pt in c...

  11. "Affective Encounters": Live Intermedial Spaces in Sites of Trauma

    Science.gov (United States)

    Scott, Jo

    2016-01-01

    This article addresses live intermediality as a tool for creative learning in the context of workshops carried out with young people in the town of Terezin, in the Czech Republic, site of the Nazi concentration camp, Theresienstadt. Live intermediality, as a mode of live media practice, involves the real time mixing and merging of sound, image,…

  12. Visual dictionaries as intermediate features in the human brain

    NARCIS (Netherlands)

    K. Ramakrishnan; H.S. Scholte; I.I.A. Groen; A.W.M. Smeulders; S. Ghebreab

    2015-01-01

    The human visual system is assumed to transform low level visual features to object and scene representations via features of intermediate complexity. How the brain computationally represents intermediate features is still unclear. To further elucidate this, we compared the biologically plausible HM

  13. Regional boreal biodiversity peaks at intermediate human disturbance.

    Science.gov (United States)

    Mayor, S J; Cahill, J F; He, F; Sólymos, P; Boutin, S

    2012-01-01

    The worldwide biodiversity crisis has intensified the need to better understand how biodiversity and human disturbance are related. The 'intermediate disturbance hypothesis' suggests that disturbance regimes generate predictable non-linear patterns in species richness. Evidence often contradicts intermediate disturbance hypothesis at small scales, and is generally lacking at large regional scales. Here, we present the largest extent study of human impacts on boreal plant biodiversity to date. Disturbance extent ranged from 0 to 100% disturbed in vascular plant communities, varying from intact forest to agricultural fields, forestry cut blocks and oil sands. We show for the first time that across a broad region species richness peaked in communities with intermediate anthropogenic disturbance, as predicted by intermediate disturbance hypothesis, even when accounting for many environmental covariates. Intermediate disturbance hypothesis was consistently supported across trees, shrubs, forbs and grasses, with temporary and perpetual disturbances. However, only native species fit this pattern; exotic species richness increased linearly with disturbance.

  14. Physical Mechanisms for Earthquakes at Intermediate Depths

    Science.gov (United States)

    Green, H. W.; Green, H. W.

    2001-12-01

    Conventional brittle shear failure it is strongly inhibited by pressure because it relies on local tensile failure. In contrast, plastic flow processes are thermally activated, making them sensitive functions of temperature, but their pressure dependence is only moderate. As a consequence, in Earth, faulting by unassisted brittle failure is probably restricted to depths less than ~ 30 km because the rocks flow at lower stresses than they fracture. To enable faulting at greater depths, mineral reactions must occur that generate a fluid or fluid-like solid that is much weaker than the parent assemblage. Although a variety of plastic instabilities have been and continue to be proposed to explain earthquakes at depth, dehydration embrittlement remains the only experimentally verified faulting mechanism consistent with the pressures and compositions existing at depths of 50-300km within subducting lithosphere. However, low pressure hydrous phases potentially abundant in subducting lithosphere (e.g. chlorite and antigorite) exhibit a temperature maximum in their stability, implying that the bulk volume change at depths of more than 70-100 km. becomes negative, thereby raising questions about mechanical instability upon dehydration. Further, it is now well-accepted that intermediate-depth earthquakes occur within the descending slab (double seismic zones present in several slabs dramatically demonstrate this fact), in conflict with the maximum depth of 10-12 km accepted for hydration of the lithosphere at oceanic spreading centers. Thus, on the one hand these earthquakes may be evidence that hydrous phases exist deep within subducting slabs but on the other hand, a mechanism for hydration to such depths is not known. One possibility is that large earthquakes outboard of trenches break the surface and allow hydration of the fault zone that can later dehydrate to yield earthquakes at depth, but no mechanism is known for pumping H2O into such fault zones to depths of tens of

  15. Talassemia β intermediária em gestante Intermediate β thalassemia in a pregnant woman

    Directory of Open Access Journals (Sweden)

    Tatiana M. Sakamoto

    2008-12-01

    Full Text Available A talassemia β é a forma considerada clinicamente a mais importante dentre as talassemias, em virtude do grau de morbidade e mortalidade, em consequência da anemia hemolítica. O presente relato de caso refere-se a uma gestante portadora da talassemia β intermediária, identificada em programa de rastreamento de anemia hemolítica e tem como objetivo demonstrar a importância do diagnóstico precoce e adequado de uma anemia hereditária, durante o pré-natal. Ressalta também a necessidade de orientação aos portadores em relação aos seus descendentes e a eficiência do acompanhamento por uma equipe multidisciplinar especializada.β-thalassemia is clinically the most important form of thalassemia due to its high level of morbidity and mortality as a result of intense hemolytic anemia. The present case report describes the case a pregnant woman who is an intermediate β-thalassemia carrier identified in a screening program for hemolytic anemia. This work aims at showing the importance of correct and early diagnosis of inherited anemia during pregnancy. It also stresses the need of guidance for carriers in respect to their progeny and discusses the efficiency of follow ups by a multidisciplinary team during pregnancy.

  16. Perspective: Spectroscopy and kinetics of small gaseous Criegee intermediates

    Science.gov (United States)

    Lee, Yuan-Pern

    2015-07-01

    The Criegee intermediates, carbonyl oxides proposed by Criegee in 1949 as key intermediates in the ozonolysis of alkenes, play important roles in many aspects of atmospheric chemistry. Because direct detection of these gaseous intermediates was unavailable until recently, previous understanding of their reactions, derived from indirect experimental evidence, had great uncertainties. Recent laboratory detection of the simplest Criegee intermediate CH2OO and some larger members, produced from ultraviolet irradiation of corresponding diiodoalkanes in O2, with various methods such as photoionization, ultraviolet absorption, infrared absorption, and microwave spectroscopy opens a new door to improved understanding of the roles of these Criegee intermediates. Their structures and spectral parameters have been characterized; their significant zwitterionic nature is hence confirmed. CH2OO, along with other products, has also been detected directly with microwave spectroscopy in gaseous ozonolysis reactions of ethene. The detailed kinetics of the source reaction, CH2I + O2, which is critical to laboratory studies of CH2OO, are now understood satisfactorily. The kinetic investigations using direct detection identified some important atmospheric reactions, including reactions with NO2, SO2, water dimer, carboxylic acids, and carbonyl compounds. Efforts toward the characterization of larger Criegee intermediates and the investigation of related reactions are in progress. Some reactions of CH3CHOO are found to depend on conformation. This perspective examines progress toward the direct spectral characterization of Criegee intermediates and investigations of the associated reaction kinetics, and indicates some unresolved problems and prospective challenges for this exciting field of research.

  17. Status of art report on intermediate energy nuclear data

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Ouk; Chang, Jong Hwa

    1997-06-01

    Nuclear reaction data of intermediate energy ranging above 20 MeV upto a few GeV form an important ingredient of several nuclear energy application, such as medical research, astrophysics, transmutation of radioactive waste and accelerator-driven reactor. Current status of the intermediate energy nuclear data cannot satisfy the requirements of these applications. Despite the fact that theories and models with suitable parameterization and fitting to the experimental data can be used for filling gaps in the available experimental database, current theories and models for intermediate nuclear energy nuclear reaction are still under development. This report summarizes required intermediate energy nuclear data and their physical quantities for the relevant research fields. Theories/models and codes developed up to now for the intermediate nuclear reaction are also outlined and transport codes based on these models are briefly introduced in this report. Available experimental facilities and data libraries are filed and trend of activities in the foreign countries on intermediate energy nuclear data are summarized. It is hoped that this report provide a part of information for the research activity on intermediate energy nuclear data in Korea to establish its long-term plan. (author). 14 tabs., 6 figs

  18. Comparison of the hemolytic activity between Candida albicans and Candida glabrata isolate,in oral cavity of HIV-infected patients%HIV感染者口腔白色念珠菌和光滑念珠菌溶血性的比较

    Institute of Scientific and Technical Information of China (English)

    罗刚; 徐平平; 董俊英

    2011-01-01

    目的:探讨HIV感染者口腔白色念珠菌和光滑念珠菌分离株的溶血性,及其与宿主机体免疫力(用CD4细胞计数表示)的关系.方法:40株白色念珠菌和加株光滑念珠菌按单一感染或是否与光滑(白色)念珠菌混合感染及CD4细胞计数的高低进行分组,采用羊血培养基法检测其溶血活性,并进行组间比较.结果:40株白色念珠菌和40株光滑念珠菌溶血活性均为阳性(100%),且光滑念珠菌的溶血性高于白色念珠菌.结论:溶血性是念珠菌的重要毒力因子,HIV感染者口腔光滑念珠菌溶血性高于白色念珠菌.%Objective To investigate the hemolytic activity of Candida albican and Candida glabrata isolates in oral cavity of HIV-infected patients, and its relationship with the immunity of the patients. Methods Forty Candida albican and 40 Candida glabrata isolates were grouped by infection types and CD4 cell count. The hemolytic activity was measured by sugar-enriched sheep blood agar medium. Results The hemolytic activity of Candida glabrate was significantly higher than that of Candida albicans (P < 0.01). Conclusion Hemolytic activity is an important virulence factor of Candida. The hemolytic activity of Candida glabrata was higher than that of Candida albicans in oral cavity of HIV-infected patients.

  19. Language in use intermediate : self-study workbook

    CERN Document Server

    Doff, Adrian

    1994-01-01

    Each of the four levels comprises about 80 hours of class work, with additional time for the self-study work. The Teacher's Book contains all the pages from the Classroom Book, with interleaved teaching notes including optional activities to cater for different abilities. There is a video to accompany the Beginner, Pre-intermediate and Intermediate levels. Each video contains eight stimulating and entertaining short programmes, as well as a booklet of photocopiable activities. Free test material is available in booklet and web format for Beginner and Pre-intermediate levels. Visit www.cambridge.org/elt/liu or contact your local Cambridge University Press representative.

  20. Spectral properties of intermediate reflectors in micromorph tandem cells

    Energy Technology Data Exchange (ETDEWEB)

    Bielawny, A.; Uepping, J.; Wehrspohn, R.B. [Institute of Physics, Martin-Luther-University Halle-Wittenberg, Heinrich-Damerow-Str. 4, 06120 Halle (Germany)

    2009-11-15

    In thin-film silicon tandem solar cells consisting of amorphous and microcrystalline silicon, efficiency enhancements can be achieved by increasing the current density in the a-Si:H top cell. Therefore, it is necessary to provide an optimized current matching at high current densities for both junctions. We present a numerical method to obtain suitable intermediate reflections achieving optimal current-matched tandem cells. We used idealized and measured reflection spectra of spectrally-selective intermediate filters for the current matching. For the optical design of such intermediate reflective layers a prediction of the spectral properties towards optimal current matching is presented. (author)

  1. Wave directional spreading at shallow and intermediate depth

    Digital Repository Service at National Institute of Oceanography (India)

    SanilKumar, V.; Deo, M.C.; Anand, N.M.

    Based on wave measurements carried out at shallow and intermediate water depths variation of directional spread parameter 's' is studied. A comparison of the mean wave directional and principal wave direction shows that the two are the same...

  2. Semiannually alternating exchange of intermediate waters east of the Philippines

    Science.gov (United States)

    Wang, Fan; Song, Lina; Li, Yuanlong; Liu, Chuanyu; Wang, Jianing; Lin, Pengfei; Yang, Guang; Zhao, Jun; Diao, Xinyuan; Zhang, Dongxiao; Hu, Dunxin

    2016-07-01

    Intermediate water exchange in the northwest tropical Pacific is explored with the temperature, salinity, and current measurements of a mooring system deployed at 8°N, 127.05°E during 2010-2014. For the first time, prominent semiannual variability (SAV; with the maximum power at ~ 187 days) of subthermocline meridional flow along the Mindanao coast is revealed. A significant correlation between meridional flow and salinity is found at intermediate depths. This provides direct evidence for the alternating transports of South Pacific and North Pacific Intermediate Waters by northward and southward undercurrents, respectively. Further analysis with an eddy-resolving ocean general circulation model demonstrates that the SAV is generated locally near the western boundary, manifesting as large-scale subthermocline recirculation and leading to alternating northward and southward flows near the Mindanao coast, which plays an efficient role in the intermediate water exchange of the northwest tropical Pacific. Mechanisms underlying the observed SAV are discussed.

  3. Packaging and transport of low and intermediate level radioactive waste

    International Nuclear Information System (INIS)

    The paper presents an overview of Nirex proposals for the packaging and transport of low and intermediate-level radioactive waste, as well as the regulatory requirements which must be met in such operations. (author)

  4. Banking on fewer children: financial intermediation, fertility and economic development.

    Science.gov (United States)

    Lehr, C S

    1999-01-01

    This study examines the influence of financial intermediation on fertility rate and labor allocation decisions. A panel Vector Autoregression model using three variables of interest, specifically, financial intermediation, fertility, and industrial employment data in 87 countries, was estimated. This convenient methodology allows the relationship between the variables to change over time. Findings indicate that the increase in wages led some households to shift from traditional labor intensive methods of production to modern sector firms. Since it is optimal for households in the modern sector to have fewer children then the labor allocation decision leads to a lower national fertility. Furthermore, results imply that the emergence and development of the financial intermediation sector will enhance modern sector employment and lower total fertility rates. Thus, the financial intermediation process is an important part of the overall developmental process. PMID:12349568

  5. Functionalization of the corrole ring: the role of isocorrole intermediates.

    Science.gov (United States)

    Tortora, Luca; Nardis, Sara; Fronczek, Frank R; Smith, Kevin M; Paolesse, Roberto

    2011-04-14

    Bromination of 3-nitro-5,10,15-triarylcorrole selectively provides two regioisomers, depending on the reaction pathway. An isocorrole species is the key intermediate to drive the reaction towards the 2-Br-17-nitro regioisomer.

  6. Banking on fewer children: financial intermediation, fertility and economic development.

    Science.gov (United States)

    Lehr, C S

    1999-01-01

    This study examines the influence of financial intermediation on fertility rate and labor allocation decisions. A panel Vector Autoregression model using three variables of interest, specifically, financial intermediation, fertility, and industrial employment data in 87 countries, was estimated. This convenient methodology allows the relationship between the variables to change over time. Findings indicate that the increase in wages led some households to shift from traditional labor intensive methods of production to modern sector firms. Since it is optimal for households in the modern sector to have fewer children then the labor allocation decision leads to a lower national fertility. Furthermore, results imply that the emergence and development of the financial intermediation sector will enhance modern sector employment and lower total fertility rates. Thus, the financial intermediation process is an important part of the overall developmental process.

  7. Advancing tandem solar cells by spectrally selective multilayer intermediate reflectors.

    Science.gov (United States)

    Hoffmann, Andre; Paetzold, Ulrich W; Zhang, Chao; Merdzhanova, Tsvetelina; Lambertz, Andreas; Ulbrich, Carolin; Bittkau, Karsten; Rau, Uwe

    2014-08-25

    Thin-film silicon tandem solar cells are composed of an amorphous silicon top cell and a microcrystalline silicon bottom cell, stacked and connected in series. In order to match the photocurrents of the top cell and the bottom cell, a proper photon management is required. Up to date, single-layer intermediate reflectors of limited spectral selectivity are applied to match the photocurrents of the top and the bottom cell. In this paper, we design and prototype multilayer intermediate reflectors based on aluminum doped zinc oxide and doped microcrystalline silicon oxide with a spectrally selective reflectance allowing for improved current matching and an overall increase of the charge carrier generation. The intermediate reflectors are successfully integrated into state-of-the-art tandem solar cells resulting in an increase of overall short-circuit current density by 0.7 mA/cm(2) in comparison to a tandem solar cell with the standard single-layer intermediate reflector. PMID:25322181

  8. New HI 21-cm absorbers at low and intermediate redshifts

    CERN Document Server

    Zwaan, M A; Péroux, C; Murphy, M T; Bouché, N; Curran, S J; Biggs, A D

    2015-01-01

    We present the results of a survey for intervening HI 21-cm absorbers at intermediate and low redshift (0180 K. A subset of our systems were also searched for OH absorption, but no detections were made.

  9. Improved enzymatic production of phenolated glycerides through alkyl phenolate intermediate

    DEFF Research Database (Denmark)

    Yang, Zhiyong; Feddern, Vivian; Glasius, Marianne;

    2011-01-01

    This work reported a novel approach for synthesis of dihydrocaffoylated glycerides, consisting of 2 steps: enzymatic synthesis of octyl dihydrocaffeate (as a synthetic intermediate) from octanol and dihydrocaffeic acid (DHCA), and enzymatic interesterification of triglycerides with octyl dihydroc...

  10. Noncovalent Intermediate of Thymidylate Synthase: Fact or Fiction?

    Science.gov (United States)

    Kholodar, Svetlana A; Kohen, Amnon

    2016-07-01

    Thymidylate synthase is an attractive target for antibiotic and anticancer drugs due to its essential role in the de novo biosynthesis of the DNA nucleotide thymine. The enzymatic reaction is initiated by a nucleophilic activation of the substrate via formation of a covalent bond to an active site cysteine. The traditionally accepted mechanism is then followed by a series of covalently bound intermediates, where that bond is only cleaved upon product release. Recent computational and experimental studies suggest that the covalent bond between the protein and substrate is actually quite labile. Importantly, these findings predict the existence of a noncovalently bound bisubstrate intermediate, not previously anticipated, which could be the target of a novel class of drugs inhibiting DNA biosynthesis. Here we report the synthesis of the proposed intermediate and findings supporting its chemical and kinetic competence. These findings substantiate the predicted nontraditional mechanism and the potential of this intermediate as a new drug lead. PMID:27327197

  11. Proceedings of the 6. National Meeting on Intermediate Energy Physics

    International Nuclear Information System (INIS)

    Several works on nuclear, hadron and quark physics are presented covering both aspects; theoretical and experimental, are presented. Emphasis is given in the intermediate energy region, several MeV centil few GeV. (L.C.)

  12. An intermediate distribution between Gaussian and Cauchy distributions

    CERN Document Server

    Liu, Tong; Dai, Wu-Sheng; Xie, Mi

    2012-01-01

    In this paper, we construct an intermediate distribution linking the Gaussian and the Cauchy distribution. We provide the probability density function and the corresponding characteristic function of the intermediate distribution. Because many kinds of distributions have no moment, we introduce weighted moments. Specifically, we consider weighted moments under two types of weighted functions: the cut-off function and the exponential function. Through these two types of weighted functions, we can obtain weighted moments for almost all distributions. We consider an application of the probability density function of the intermediate distribution on the spectral line broadening in laser theory. Moreover, we utilize the intermediate distribution to the problem of the stock market return in quantitative finance.

  13. Assembly characteristics of plant keratin intermediate filaments in vitro

    Institute of Scientific and Technical Information of China (English)

    闵光伟; 杨澄; 佟向军; 翟中和

    1999-01-01

    After selective extraction and purification, plant keratin intermediate filaments were reassembled in vitro. Scanning tunneling microscope (STM) and transmission electron microscope (TEM) micrographs showed that acidic keratins and basic keratins can assemble into dimers and further into 10 nm filaments in vitro. In higher magnification images, it can be seen that fully assembled plant keratin intermediate filaments consist of several thinner filaments of 3 nm in diameter, which indicates the formation of protofilaments in the assembly processes. One of the explicit features of plant keratin intermediate filaments is a 24—25 nm periodic structural repeat alone the axis of beth the 10 nm filaments and protofilaments. The periodic repeat is one of the fundamental characteristic of all intermediate filaments, and demonstrates the half staggered arrangement of keratin molecules within the filaments.

  14. The Intermediate Impossible: A Prewriting Activity for Creative Problem Solving.

    Science.gov (United States)

    Karloff, Kenneth

    1985-01-01

    Adapts Edward de Bono's "Intermediate Impossible" strategy--for considering ideas that normally would be discarded as stepping-stones to new ideas--for use as a prewriting activity to enhance creative problem solving. (HTH)

  15. On the origin of intermediate effects in clinical case recall

    OpenAIRE

    Schmidt, Henk; Boshuizen, Henny

    1993-01-01

    textabstractIn two experiments, the effects of level of medical expertise and study time on free recall of a clinical case were assessed. In Experiment 1, a nonmonotonic relationship between level of expertise and recall was found: Subjects of intermediate levels of expertise remembered more information from the case than both experts and novices. This "intermediate effect" disappeared, however, when study time was restricted. Analysis of post hoc acquired protocols of pathophysiological know...

  16. Threshold Effect and Financial Intermediation in Economic Development

    OpenAIRE

    Soedarmono, Wahyoe; Augier, Laurent

    2009-01-01

    This paper analyzes the importance of financial intermediation on economic growth. Using the Neoclassical growth framework, we raise a new issue where our model has multiple stationary states with threshold effect. We further confirm that financial intermediation is better than self-financing system in order to ensure the existence and uniqueness of long-run steady state equilibrium of capital stock, as well as to decrease threshold level. The presence of threshold effect is an important find...

  17. A Search-Theoretic Approach to Efficient Financial Intermediation

    OpenAIRE

    Fabien Tripier

    2014-01-01

    This article develops a search-theoretic model of financial intermediation to study the efficiency condition of the banking sector. Competitive financial intermediation is determined by the search decisions of both households (to find adequate financial products) and banks (to attract depositors through marketing and to select borrowers through auditing) and by the interest rate setting mechanism. The efficiency of the competitive economy requires that interest rates are posted by banks or ar...

  18. Characteristics of bank financial intermediation in Croatian counties

    OpenAIRE

    Jakša Krišto; Iva Mandac

    2015-01-01

    Research on bank financial intermediation in a country’s narrower territorial units is scarce, in both domestic and international literature. Banks are almost the only financial intermediaries in narrower territorial units and their role is substantial, ranging from participating in regional development to the successful running of their own business. Hence, the main objective of this paper is to examine the characteristics of the financial intermediation of banks in the counties of the Repub...

  19. Inhibition of trichloroethylene oxidation by the transformation intermediate carbon monoxide.

    OpenAIRE

    Henry, S M; Grbić-Galić, D

    1991-01-01

    Inhibition of trichloroethylene (TCE) oxidation by the transformation intermediate carbon monoxide (CO) was evaluated with the aquifer methanotroph Methylomonas sp. strain MM2. CO was a TCE transformation intermediate. During TCE oxidation, approximately 9 mol% of the TCE was transformed to CO. CO was oxidized by Methylomonas sp. strain MM2, and when formate was provided as an electron donor, the CO oxidation rate doubled. The rate of CO oxidation without formate was 4.6 liter mg (dry weight)...

  20. Intermediate statistics as a consequence of deformed algebra

    OpenAIRE

    Lavagno, A.; Swamy, P. Narayana

    2009-01-01

    We present a formulation of the deformed oscillator algebra which leads to intermediate statistics as a continuous interpolation between the Bose-Einstein and Fermi-Dirac statistics. It is deduced that a generalized permutation or exchange symmetry leads to the introduction of the basic number and it is then established that this in turn leads to the deformed algebra of oscillators. We obtain the mean occupation number describing the particles obeying intermediate statistics which thus establ...

  1. Thermogravimetric control of intermediate compounds in uranium metallurgy

    International Nuclear Information System (INIS)

    The thermal decomposition of some intermediate compounds in the metallurgy of the uranium as uranium peroxide, ammonium uranate, uranium and ammonium penta-fluoride, uranium tetrafluoride and uranous oxide has been study by means of the Chevenard's thermo balance. Some data on pyrolysis of synthetic mixtures of intermediate compounds which may occasionally appear during the industrial process, are given. Thermogravimetric methods of control are suggested, usable in interesting products in the uranium metallurgy. (Author) 20 refs

  2. Intermediate energy light sources and the SSRF project

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Advances in insertion device technology, top-up operation and superconducting RF cavities make it possible to generate high brightness X-ray with intermediate energy light sources, which leads a new trend in designing and constructing third generation light sources around the world. The development status and the remarkable technical features of intermediate energy light sources are reviewed, and the main SSRF properties are described in this paper.

  3. Fibrinolysis for patients with intermediate-risk pulmonary embolism

    OpenAIRE

    Meyer, Guy; Vicaut, Eric; Danays, Thierry; Agnelli, Giancarlo; Becattini, Cecilia; Beyer-Westendorf, Jan; Bluhmki, Erich; Bouvaist, Helene; Brenner, Benjamin; Couturaud, Francis; Dellas, Claudia; Empen, Klaus; Franca, Ana; Galiè, Nazzareno; Geibel, Annette

    2014-01-01

    BACKGROUND The role of fibrinolytic therapy in patients with intermediate-risk pulmonary embolism is controversial. METHODS In a randomized, double-blind trial, we compared tenecteplase plus heparin with placebo plus heparin in normotensive patients with intermediate-risk pulmonary embolism. Eligible patients had right ventricular dysfunction on echocardiography or computed tomography, as well as myocardial injury as indicated by a positive test for cardiac troponin I or troponin ...

  4. Some features of nucleus-nucleus collisions at intermediate energies

    International Nuclear Information System (INIS)

    The so-called intermediate energies are energies for which different reaction mechanisms, intrinsically incompatible, are expected to compete. An energy of a few tens of MeV per nucleon is the limit between two different regimes of nuclear reactions. The characteristics of the changing collision mechanism are detailed in these lectures, particularly through information collected during the first five years of operation of Ganil. Then a synthesis of new nuclear species in intermediate energy heavy ion reactions is given

  5. On Physical and Mechanical Behavior of Natural Marine Intermediate Deposites

    Institute of Scientific and Technical Information of China (English)

    SHI Ming-lei; DENG Xue-jun

    2005-01-01

    Coastal structures may be built on natural sedimentary intermediate grounds, which mainly consist of silty soils and fine sandy soils. In this study, extensive field and laboratory tests were performed on the natural marine intermediate deposits to demonstrate the difference in behavior between natural marine clayey soils and natural marine intermediate deposits. The natural intermediate deposits have almost the same ratios of natural water content to liquid limit as those of the soft natural marine clays, but the former have much higher in-situ strength and sensitivity than the latter. The research results indicate that grain size distributions of soils affect significantly tip resistance obtained in field cone penetration tests. The mechanical parameters of natural marine intermediate deposits are also significantly affected by sample disturbance due to their high sensitivity and relatively large permeability. Unconfined compression shear tests largely underestimate the strength of natural marine intermediate soils. The triaxial consolidated compression shear tests with simulated in-situ confined pressure give results much better than those of uncomfined compression shear tests.

  6. Analysis of dynein intermediate chains, light intermediate chains and light chains in a cohort of hereditary peripheral neuropathies.

    Science.gov (United States)

    Tey, Shelisa; Ahmad-Annuar, Azlina; Drew, Alexander P; Shahrizaila, Nortina; Nicholson, Garth A; Kennerson, Marina L

    2014-10-01

    The cytoplasmic dynein heavy chain (DYNC1H1) gene has been increasingly associated with neurodegenerative disorders including axonal Charcot-Marie-Tooth disease (CMT2), intellectual disability and malformations of cortical development. In addition, evidence from mouse models (Loa, catabolite repressor-activator (Cra) and Sprawling (Swl)) has shown that mutations in Dync1h1 cause a range of neurodegenerative phenotypes with motor and sensory neuron involvement. In this current study, we examined the possible contribution of other cytoplasmic dynein subunits that bind to DYNC1H1 as a cause of inherited peripheral neuropathy. We focused on screening the cytoplasmic dynein intermediate, light intermediate and light chain genes in a cohort of families with inherited peripheral neuropathies. Nine genes were screened and ten variants were detected, but none was identified as pathogenic, indicating that cytoplasmic dynein intermediate, light intermediate and light chains are not a cause of neuropathy in our cohort.

  7. General educational disciplines practice-oriented training in intermediate vocational education

    OpenAIRE

    Liya G. Skorobogatova

    2011-01-01

    The article concerns crucial issues of practice-oriented training in Russia's intermediate vocational education, designates directions of general educational disciplines study in intermediate vocational education.

  8. Top predators induce the evolutionary diversification of intermediate predator species.

    Science.gov (United States)

    Zu, Jian; Yuan, Bo; Du, Jianqiang

    2015-12-21

    We analyze the evolutionary branching phenomenon of intermediate predator species in a tritrophic food chain model by using adaptive dynamics theory. Specifically, we consider the adaptive diversification of an intermediate predator species that feeds on a prey species and is fed upon by a top predator species. We assume that the intermediate predator׳s ability to forage on the prey can adaptively improve, but this comes at the cost of decreased defense ability against the top predator. First, we identify the general properties of trade-off relationships that lead to a continuously stable strategy or to evolutionary branching in the intermediate predator species. We find that if there is an accelerating cost near the singular strategy, then that strategy is continuously stable. In contrast, if there is a mildly decelerating cost near the singular strategy, then that strategy may be an evolutionary branching point. Second, we find that after branching has occurred, depending on the specific shape and strength of the trade-off relationship, the intermediate predator species may reach an evolutionarily stable dimorphism or one of the two resultant predator lineages goes extinct. PMID:26431773

  9. Top predators induce the evolutionary diversification of intermediate predator species.

    Science.gov (United States)

    Zu, Jian; Yuan, Bo; Du, Jianqiang

    2015-12-21

    We analyze the evolutionary branching phenomenon of intermediate predator species in a tritrophic food chain model by using adaptive dynamics theory. Specifically, we consider the adaptive diversification of an intermediate predator species that feeds on a prey species and is fed upon by a top predator species. We assume that the intermediate predator׳s ability to forage on the prey can adaptively improve, but this comes at the cost of decreased defense ability against the top predator. First, we identify the general properties of trade-off relationships that lead to a continuously stable strategy or to evolutionary branching in the intermediate predator species. We find that if there is an accelerating cost near the singular strategy, then that strategy is continuously stable. In contrast, if there is a mildly decelerating cost near the singular strategy, then that strategy may be an evolutionary branching point. Second, we find that after branching has occurred, depending on the specific shape and strength of the trade-off relationship, the intermediate predator species may reach an evolutionarily stable dimorphism or one of the two resultant predator lineages goes extinct.

  10. CONDITIONING OF INTERMEDIATE-LEVEL WASTE AT FORSCHUNGSZENTRUM JUELICH GMBH

    Energy Technology Data Exchange (ETDEWEB)

    Krumbach, H.

    2003-02-27

    This contribution to the group of low-level, intermediate, mixed and hazardous waste describes the conditioning of intermediate-level mixed waste (dose rate above 10 mSv/h at the surface) from Research Centre Juelich (FZJ). Conditioning of the waste by supercompaction is performed at Research Centre Karlsruhe (FZK). The waste described is radioactive waste arising from research at Juelich. This waste includes specimens and objects from irradiation experiments in the research reactors Merlin (FRJ-1) and Dido (FRJ-2) at FZJ. In principle, radioactive waste at Forschungszentrum Juelich GmbH is differentiated by the surface dose rate at the waste package. Up to a surface dose rate of 10 mSv/h, the waste is regarded as low-level. The radioactive waste described here has a surface dose rate above 10 mSv/h. Waste up to 10 mSv/h is conditioned at the Juelich site according to different conditioning methods. The intermediate-level waste can only be conditioned by supercompaction in the processing facility for intermediate-level waste from plant operation at Research Centre Karlsruhe. Research Centre Juelich also uses this waste cell to condition its intermediate-level waste from plant operation.

  11. Transiting Sub-stellar companions of Intermediate-mass stars

    Directory of Open Access Journals (Sweden)

    Sebastian Daniel

    2015-01-01

    Full Text Available We use the CoRoT-survey to search for transiting close-in planets of intermediate-mass stars (M* = 1.3 − 2.1 M⊙. We present recent results of our survey. RV-surveys and direct imaging campaigns showed, that intermediate-mass main-sequence stars have more massive planets then solar-like stars. Even brown dwarfs have been found. In our study we concentrated on short-period planets for which a mass-determination is possible. The detection of close-in planets of intermediate-mass stars put strong constraints on the timescales of the formation and migration. We already have identified transiting Jupiter-like planet candidates with short orbital periods and observed these candidates with high-resolution echelle-spectrographs at various Telescopes.

  12. Photocatalytic oxidation of paracetamol: dominant reactants, intermediates, and reaction mechanisms.

    Science.gov (United States)

    Yang, Liming; Yu, Liya E; Ray, Madhumita B

    2009-01-15

    The role of primary active species (ecb(-), hvb(+), *OH, HO2*, O2*(-), and H2O2) during photocatalytic degradation of paracetamol (acetaminophen) using TiO2 catalyst was systematically investigated. Hydroxyl radicals (*OH) are responsible for the major degradation of paracetamol with a second-order rate constant (1.7 x 10(9) M(-1) s(-1)) for an *OH-paracetamol reaction. A total of 13 intermediates was identified and classified into four categories: (i) aromatic compounds, (ii) carboxylic acids, (iii) nitrogen-containing straight chain compounds, and (iv) inorganic species (ammonium and nitrate ions). Concentration profiles of identified intermediates indicate that paracetamol initially undergoes hydroxylation through *OH addition onto the aromatic ring at ortho (predominantly), meta, and para positions with respect to the -OH position of paracetamol. This initial *OH hydroxylation is followed by further oxidation generating carboxylic acids. Subsequent mineralization of smaller intermediates eventually increases ammonium and nitrate concentration in the system. PMID:19238980

  13. Characterization of the Partially Folded Monomeric Intermediate of Creatine Kinase

    Institute of Scientific and Technical Information of China (English)

    朴龙斗; 周海梦

    2002-01-01

    The importance of understanding the protein folding pathway and intermediates is well recognized on the basis of extensive studies of protein folding in vitro and in vivo. Creatine kinase (CK) is a typical model for studying unfolding and refolding of proteins due to several interesting properties. Recent studies on the folding of CK show that its partially folded monomeric intermediate is present kinetically and is stable at equilibrium. The present paper contains 33 References as a mini review to characterize the properties of CK from studies on the CK folding pathway. Characterization of these intermediates is an essential step toward understanding the mechanism of protein folding. Some well-determined schemes are suggested as protein folding models.

  14. Deglacial intermediate water reorganization: new evidence from the Indian Ocean

    Directory of Open Access Journals (Sweden)

    S. Romahn

    2013-07-01

    Full Text Available The importance of intermediate water masses in climate change and ocean circulation has been emphasized recently. In particular, Antarctic Intermediate Water (AAIW is thought to have acted as an active interhemispheric transmitter of climate anomalies. Here we reconstruct changes in AAIW signature and spatial and temporal evolution based on a 40 kyr time series of oxygen and carbon isotopes as well as planktic Mg/Ca based thermometry from a site in the western Indian Ocean. Our data suggest that AAIW transmitted Antarctic temperature trends to the equatorial Indian Ocean via the "oceanic tunnel" mechanism. Moreover, our results reveal that deglacial AAIW carried a signature of aged Southern Ocean deep water. We find no evidence of increased formation of intermediate waters during the deglaciation.

  15. Intermediate Collaborative Adaptive Management Strategies Build Stakeholder Capacity

    Directory of Open Access Journals (Sweden)

    Martha C. Monroe

    2013-06-01

    Full Text Available Efforts to implement collaborative adaptive management (CAM often suffer from challenges, such as an unwillingness of managers to share power, unresolved conflicts between stakeholders, and lack of capacity among stakeholders. Some aspects considered essential to CAM, e.g., trust and stakeholder capacity, may be more usefully viewed as goals for intermediate strategies rather than a set of initial conditions. From this perspective, intermediate steps that focus on social learning and building experience could overcome commonly cited barriers to CAM. An exploration of Springs Basin Working Groups, organized around major clusters of freshwater springs in north Florida, provides a case study of how these intermediate steps enable participants to become more reasonable and engaged. This strategy may be easily implemented by agencies beginning a CAM process.

  16. Intermediate-energy neutron beam for NCT at MURR

    International Nuclear Information System (INIS)

    The University of Missouri Research Reactor (MURR) is one of the high-flux reactors in the USA and it can be used to produce an intense beam of intermediate-energy neutrons for neutron capture therapy. Two methods are being evaluated at MURR to produce such a beam. The first uses a moderator of Al2O3 replacing part of the graphite and water on one side of the core of the reactor to produce a source of predominantly intermediate-energy neutrons. The second method is a filter of 238U between the core and the patient position to pass only intermediate-energy neutrons. The results of these evaluations are presented in this paper along with an outline of the other resources at the University of Missouri-Columbia that are available to support an NCT program. 4 references, 7 figures, 1 table

  17. Negotiating comfort in low energy housing: The politics of intermediation

    International Nuclear Information System (INIS)

    Optimising the energy performance of buildings is technically and economically challenging but it also has significant social implications. Maintaining comfortable indoor conditions while reducing energy consumption involves careful design, construction, and management of the built environment and its inhabitants. In this paper, we present findings from the study of a new low energy building for older people in Grenoble, France where conflicts emerged over the simultaneous pursuit of energy efficiency and comfort. The findings contribute to the contemporary literature on the sociotechnical study of buildings and energy use by focusing on intermediation, those activities that associate a technology to end users. Intermediation activities take many forms, and in some cases, can result in the harmonisation or alignment of energy efficiency goals and comfort goals. In other cases, intermediation is unsuccessful, leading to the conventional dichotomy between optimising technical performance and meeting occupant preferences. By highlighting the multiple ways that comfort and energy efficiency is negotiated, we conclude that buildings are provisional achievements that are constantly being intermediated. This suggests that building energy efficiency policies and programmes need to provide opportunities for intermediaries to negotiate the desires and preferences of the multiple stakeholders that are implicated in low energy buildings. -- Highlights: •Energy efficiency and comfort are two possibly contradictory aims of buildings. •We study the pursuit of these aims at the occupation stage of a new building. •Aligning these aims involve negotiating them with occupants. •Intermediation processes are key to such negotiations. •Intermediation processes involve both actors and technical devices

  18. Soluble ICAM-1 serum levels in patients with intermediate uveitis

    OpenAIRE

    Klok, A.M.; Luyendijk, L.; Zaal, M.J.W.; Rothova, A; Kijlstra, A

    1999-01-01

    AIM—To investigate whether serum levels of soluble intercellular adhesion molecule 1 (sICAM-1) can serve as a marker of the presence of systemic disease in intermediate uveitis.
METHODS—In a multicentre study sICAM-1 serum levels were measured in 61 patients with idiopathic intermediate uveitis, controls included 56 uveitis patients with a systemic disease (26 sarcoid associated uveitis and 30 HLA-B27 positive acute anterior uveitis), 58 uveitis patients without systemic disease (30 toxoplasm...

  19. Intermediate guide to SPSS programming using syntax for data management

    CERN Document Server

    Boslaugh, Sarah E

    2004-01-01

    An Intermediate Guide to SPSS Programming: Using Syntax for Data Management introduces the major tasks of data management and presents solutions using SPSS syntax. This book fills an important gap in the education of many students and researchers, whose coursework has left them unprepared for the data management issues that confront them when they begin to do independent research. It also serves as an introduction to SPSS programming. All the basic features of SPSS syntax are illustrated, as are many intermediate and advanced topics such as using vectors and loops, reading complex data files,

  20. Intermediate Mass Fragments Emission in Peripheral Heavy-Ion Collisions

    Science.gov (United States)

    Bini, M.; Casini, G.; Maurenzig, P. R.; Olmi, A.; Pasquali, G.; Piantelli, S.; Poggi, G.; Stefanini, A. A.; Taccetti, N.

    The collision 116Sn + 93Nb at 29.5 AMeV in direct and reverse kinematics has been studied at LNS in Catania. In particular the emission pattern in the νperp - νpar plane of Intermediate Mass Fragments with Z=3-7 (IMF's) shows that for peripheral reactions most of IMF's are emitted at velocities intermediate between those of the projectile- and target-like products. From coulomb trajectory calculations one can infere that these IMF's are produced mainly in the interaction zone, in a short time interval at the end of the target-projectile interaction.