Partial stem and leaf resistance against the fungal pathogen Botrytis cinerea in wild relatives of tomato

NARCIS (Netherlands)

Have, ten A.; Berloo, van R.; Lindhout, P.; Kan, van J.A.L.

2007-01-01

Tomato (Solanum lycopersicum) is one of many greenhouse crops that can be infected by the necrotrophic ascomycete Botrytis cinerea. Commercial cultivation of tomato is hampered by the lack of resistance. Quantitative resistance has been reported in wild tomato relatives, mostly based on leaf assays.

A review of the Mycrocylus ulei Ascomycetes fungus, causative agent of South American rubber-leaf blight Revisión sobre el hongo Microcyclus ulei, agente causal del mal suramericano de la hoja del caucho

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Ancízar Aristizábar Fabio

2006-12-01

Full Text Available The Microcyclus ulei Ascomycetes fungus is the causal agent of south-American leaf blight (SALB, this being one of the most important diseases affecting the natural rubber tree (Hevea brasiliensis in Latina-America and has been responsible for numerous economic losses. This fungus has presented high physiological variability, suggesting its great adaptability. HCN tolerance has been described as being one of the mechanisms associated with its virulence. Resistant Hevea clones have been obtained by genetic improvement; however, the mechanisms associated with this are still not well known. Greater knowledge of this pathogen will lead to developing new control strategies and better understanding of the mechanisms associated with host resistance. Key words: Microcyclus ulei, SALB, Hevea brasiliensis.El hongo ascomycete Microcyclus ulei es el agente causal del SALB que es una de las enfermedades más importan­tes del árbol de caucho natural (Hevea brasiliensis en América Latina y ha sido responsable de numerosas pérdidas económicas. Este hongo ha presentado alta variabilidad fisiológica y se sugiere su alta adaptabilidad, dentro de los mecanismos asociados a su virulencia se ha descrito la tolerancia al HCN. Se han obtenido clones de Hevea resistentes mediante mejoramiento genético, sin embargo, aun no son bien conocidos los mecanismos asociados a ésta. Un mayor conocimiento de este patógeno permitirá el desarrollo de nuevas estrategias de control así como el mayor entendimiento de los mecanismos asociados a resistencia del hospedero. Palabras clave: Microcyclus ulei, SALB, Hevea brasiliensis.

Multivariate analysis of the Scutellinia umbrorum complex (Pezizales, Ascomycetes) from five ecotopes in the Netherlands

NARCIS (Netherlands)

Paal, Jaanus; Kullman, Bellis; Huijser, Henk A.

1998-01-01

The multivariate structure of the Scutellinia umbrorum complex ( Pezizales, Ascomycetes), based on the morphometrical parameters of 81 specimens from five ecotopes in the Netherlands, was analysed. According to conventional expert estimation, five putative taxa resp. species were established: S.

A MADS box protein interacts with a mating-type protein and is required for fruiting body development in the homothallic ascomycete Sordaria macrospora.

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Nolting, Nicole; Pöggeler, Stefanie

2006-07-01

MADS box transcription factors control diverse developmental processes in plants, metazoans, and fungi. To analyze the involvement of MADS box proteins in fruiting body development of filamentous ascomycetes, we isolated the mcm1 gene from the homothallic ascomycete Sordaria macrospora, which encodes a putative homologue of the Saccharomyces cerevisiae MADS box protein Mcm1p. Deletion of the S. macrospora mcm1 gene resulted in reduced biomass, increased hyphal branching, and reduced hyphal compartment length during vegetative growth. Furthermore, the S. macrospora Deltamcm1 strain was unable to produce fruiting bodies or ascospores during sexual development. A yeast two-hybrid analysis in conjugation with in vitro analyses demonstrated that the S. macrospora MCM1 protein can interact with the putative transcription factor SMTA-1, encoded by the S. macrospora mating-type locus. These results suggest that the S. macrospora MCM1 protein is involved in the transcriptional regulation of mating-type-specific genes as well as in fruiting body development.

Quantitative trait loci for resistance to two fungal pathogens in Quercus robur

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Cécile Robin; Amira Mougou-Hamdane; Jean-Marc Gion; Antoine Kremer; Marie-Laure. Desprez-Loustau

2012-01-01

Powdery mildew, caused by Erysiphe alphitoides (Ascomycete), is the most frequent disease of oaks, which are also known to be host plants for Phytophthora cinnamomi (Oomycete), the causal agent of ink disease. Components of genetic resistance to these two pathogens, infecting either leaves or root and collar, were...

Comparative Analysis of Secretome Profiles of Manganese(II-Oxidizing Ascomycete Fungi.

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Carolyn A Zeiner

Full Text Available Fungal secretomes contain a wide range of hydrolytic and oxidative enzymes, including cellulases, hemicellulases, pectinases, and lignin-degrading accessory enzymes, that synergistically drive litter decomposition in the environment. While secretome studies of model organisms such as Phanerochaete chrysosporium and Aspergillus species have greatly expanded our knowledge of these enzymes, few have extended secretome characterization to environmental isolates or conducted side-by-side comparisons of diverse species. Thus, the mechanisms of carbon degradation by many ubiquitous soil fungi remain poorly understood. Here we use a combination of LC-MS/MS, genomic, and bioinformatic analyses to characterize and compare the protein composition of the secretomes of four recently isolated, cosmopolitan, Mn(II-oxidizing Ascomycetes (Alternaria alternata SRC1lrK2f, Stagonospora sp. SRC1lsM3a, Pyrenochaeta sp. DS3sAY3a, and Paraconiothyrium sporulosum AP3s5-JAC2a. We demonstrate that the organisms produce a rich yet functionally similar suite of extracellular enzymes, with species-specific differences in secretome composition arising from unique amino acid sequences rather than overall protein function. Furthermore, we identify not only a wide range of carbohydrate-active enzymes that can directly oxidize recalcitrant carbon, but also an impressive suite of redox-active accessory enzymes that suggests a role for Fenton-based hydroxyl radical formation in indirect, non-specific lignocellulose attack. Our findings highlight the diverse oxidative capacity of these environmental isolates and enhance our understanding of the role of filamentous Ascomycetes in carbon turnover in the environment.

Comparative Analysis of Secretome Profiles of Manganese(II)-Oxidizing Ascomycete Fungi

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Zeiner, Carolyn A.; Purvine, Samuel O.; Zink, Erika M.; Paša-Tolić, Ljiljana; Chaput, Dominique L.; Haridas, Sajeet; Wu, Si; LaButti, Kurt; Grigoriev, Igor V.; Henrissat, Bernard; Santelli, Cara M.; Hansel, Colleen M.; Pöggeler, Stefanie

2016-07-19

Fungal secretomes contain a wide range of hydrolytic and oxidative enzymes, including cellulases, hemicellulases, pectinases, and lignin-degrading accessory enzymes, that synergistically drive litter decomposition in the environment. While secretome studies of model organisms such as Phanerochaete chrysosporium and Aspergillus species have greatly expanded our knowledge of these enzymes, few have extended secretome characterization to environmental isolates or conducted side-by-side comparisons of diverse species. Thus, the mechanisms of carbon degradation by many ubiquitous soil fungi remain poorly understood. Here we use a combination of LC-MS/MS, genomic, and bioinformatic analyses to characterize and compare the protein composition of the secretomes of four recently isolated, cosmopolitan, Mn(II)-oxidizing Ascomycetes (Alternaria alternata SRC1lrK2f, Stagonospora sp. SRC1lsM3a, Pyrenochaeta sp. DS3sAY3a, and Paraconiothyrium sporulosum AP3s5-JAC2a). We demonstrate that the organisms produce a rich yet functionally similar suite of extracellular enzymes, with species-specific differences in secretome composition arising from unique amino acid sequences rather than overall protein function. Furthermore, we identify not only a wide range of carbohydrate-active enzymes that can directly oxidize recalcitrant carbon, but also an impressive suite of redox-active accessory enzymes that suggests a role for Fenton-based hydroxyl radical formation in indirect, non-specific lignocellulose attack. Our findings highlight the diverse oxidative capacity of these environmental isolates and enhance our understanding of the role of filamentous Ascomycetes in carbon turnover in the environment.

Purifying Selection and Birth-and-Death Evolution in the Class II Hydrophobin Gene Families of the Ascomycete Trichoderma/Hypocrea

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kubicek, Christian P.; Baker, Scott E.; Gamauf, Christian; Kenerley, Chuck; Druzhinina, Irina S.

2008-01-10

Hydrophobins are proteins containing eight conserved cysteine residues that occur uniquely in mycelial fungi, where their main function is to confer hydrophobicity to fungal surfaces in contact with air and during attachment of hyphae to hydrophobic surfaces of hosts, symbiotic partners or of themselves resulting in morphogenetic signals. Based on their hydropathy patterns and their solubility characteristics, they are classified in class I and class II hydrophobins, the latter being found only in ascomycetes. Here we have investigated the mechanisms driving the evolution of the class II hydrophobins in nine species of the mycoparasitic ascomycetous genus Trichoderma/Hypocrea, using three fully sequenced genomes (H. jecorina=T. reesei, H. atroviridis=T. atroviride; H. virens=T. virens) and a total of 14.000 ESTs of six others (T. asperellum, H. lixii=T. harzianum, T. aggressivum var. europeae, T. longibrachiatum, T. cf. viride). The former three contained six, ten and nine members, which is the highest number found in any other ascomycete so far. They all showed the conserved four beta-strands/one helix structure, which is stabilized by four disulfide bonds. In addition, a small number of these HFBs contained an extended N-terminus rich in either praline and aspartate, or glycine-asparagine. Phylogenetic analysis reveals a mosaic of terminal clades contain duplicated genes and shows only three reasonably supported clades. Calculation of the ratio of differences in synonymous vs. non-synonymous nucleotide substitutions provides evidence for strong purifying selection (KS/Ka >> 1). A genome database search for class II HFBs from other ascomycetes retrieved a much smaller number of hydrophobins (2-4) from each species, and most of them were from Pyrenomycetes. A combined phylogeny of these sequences with those of Trichoderma showed that the Trichoderma HFBs mostly formed their own clades, whereas those of other pyrenomycetes occured in shared clades. Our study shows

The filamentous ascomycete Sordaria macrospora can survive in ambient air without carbonic anhydrases.

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Lehneck, Ronny; Elleuche, Skander; Pöggeler, Stefanie

2014-06-01

The rapid interconversion of carbon dioxide and bicarbonate (hydrogen carbonate) is catalysed by metalloenzymes termed carbonic anhydrases (CAs). CAs have been identified in all three domains of life and can be divided into five evolutionarily unrelated classes (α, β, γ, δ and ζ) that do not share significant sequence similarities. The function of the mammalian, prokaryotic and plant α-CAs has been intensively studied but the function of CAs in filamentous ascomycetes is mostly unknown. The filamentous ascomycete Sordaria macrospora codes for four CAs, three of the β-class and one of the α-class. Here, we present a functional analysis of CAS4, the S. macrospora α-class CA. The CAS4 protein was post-translationally glycosylated and secreted. The knockout strain Δcas4 had a significantly reduced rate of ascospore germination. To determine the cas genes required for S. macrospora growth under ambient air conditions, we constructed double and triple mutations of the four cas genes in all possible combinations and a quadruple mutant. Vegetative growth rate of the quadruple mutant lacking all cas genes was drastically reduced compared to the wild type and invaded the agar under normal air conditions. Likewise the fruiting bodies were embedded in the agar and completely devoid of mature ascospores. © 2014 John Wiley & Sons Ltd.

A chloride tolerant laccase from the plant pathogen ascomycete Botrytis aclada expressed at high levels in Pichia pastoris.

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Kittl, Roman; Mueangtoom, Kitti; Gonaus, Christoph; Khazaneh, Shima Tahvilda; Sygmund, Christoph; Haltrich, Dietmar; Ludwig, Roland

2012-01-20

Fungal laccases from basidiomycetous fungi are thoroughly investigated in respect of catalytic mechanism and industrial applications, but the number of reported and well characterized ascomycetous laccases is much smaller although they exhibit interesting catalytic properties. We report on a highly chloride tolerant laccase produced by the plant pathogen ascomycete Botrytis aclada, which was recombinantly expressed in Pichia pastoris with an extremely high yield and purified to homogeneity. In a fed-batch fermentation, 495 mg L(-1) of laccase was measured in the medium, which is the highest concentration obtained for a laccase by a yeast expression system. The recombinant B. aclada laccase has a typical molecular mass of 61,565 Da for the amino acid chain. The pI is approximately 2.4, a very low value for a laccase. Glycosyl residues attached to the recombinant protein make up for approximately 27% of the total protein mass. B. aclada laccase exhibits very low K(M) values and high substrate turnover numbers for phenolic and non-phenolic substrates at acidic and near neutral pH. The enzyme's stability increases in the presence of chloride ions and, even more important, its substrate turnover is only weakly inhibited by chloride ions (I(50)=1.4M), which is in sharp contrast to most other described laccases. This high chloride tolerance is mandatory for some applications such as implantable biofuel cells and laccase catalyzed reactions, which suffer from the presence of chloride ions. The high expression yield permits fast and easy production for further basic and applied research. Copyright © 2011 Elsevier B.V. All rights reserved.

Functional Analysis of Developmentally Regulated Genes chs7 and sec22 in the Ascomycete Sordaria macrospora.

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Traeger, Stefanie; Nowrousian, Minou

2015-04-14

During sexual development, filamentous ascomycetes form complex, three-dimensional fruiting bodies for the generation and dispersal of spores. In previous studies, we identified genes with evolutionary conserved expression patterns during fruiting body formation in several fungal species. Here, we present the functional analysis of two developmentally up-regulated genes, chs7 and sec22, in the ascomycete Sordaria macrospora. The genes encode a class VII (division III) chitin synthase and a soluble N-ethylmaleimide-sensitive-factor attachment protein receptor (SNARE) protein, respectively. Deletion mutants of chs7 had normal vegetative growth and were fully fertile but showed sensitivity toward cell wall stress. Deletion of sec22 resulted in a reduced number of ascospores and in defects in ascospore pigmentation and germination, whereas vegetative growth was normal in the mutant. A SEC22-EGFP fusion construct under control of the native sec22 promoter and terminator regions was expressed during different stages of sexual development. Expression of several development-related genes was deregulated in the sec22 mutant, including three genes involved in melanin biosynthesis. Our data indicate that chs7 is dispensable for fruiting body formation in S. macrospora, whereas sec22 is required for ascospore maturation and germination and thus involved in late stages of sexual development. Copyright © 2015 Traeger and Nowrousian.

DIVERSITY OF SAPROTROPHIC ANAMORPHIC ASCOMYCETES FROM NATIVE FORESTS IN ARGENTINA: AN UPDATED REVIEW

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Natalia Allegrucci

2009-01-01

Full Text Available En Argentina se reconocen ocho regiones de bosques nativos: bosque Andino-Patagónico, Talares de la Región Pampeana, Parque Chaqueño, Selva Misionera, Selva Tucumano-Boliviana, Monte, Espinal y Bosques Pluviales de los ríos Paraguay, Paraná y Uruguay. El objetivo de este trabajo ha sido reunir y revisar la información sobre la biodiversidad de microhongos saprótrofos (Ascomycetes anamórficos citados en los bosques nativos de Argentina, desde las primeras colecciones de Spegazzini hasta el presente. De las regiones anteriormente mencionadas los bosques Andino-Patagónicos, Bosques Pluviales de los ríos Paraguay, Paraná y Uruguay y recientemente los Talares de la provincia de Buenos Aires son aquellos donde se han realizado más exploraciones de microhongos saprótrofos. Por otro lado se obtuvieron muy pocos registros de especies fúngicas del resto de los bosques; para la región de Monte en particular no se han realizado hasta el presente estudios de hongos anamórficos, por lo cual no se cuenta con registros de especies anamórficas de Ascomycetes. Como resultado de una revisión bibliográfica exhaustiva, se registraron 344 especies, de las cuales 81 (23,5% son nuevas especies. Este trabajo pone de manifiesto la falta de exploraciones de áreas de importancia en nuestro país, y muestra la necesidad de incrementar estos estudios.

Plant biomass degrading ability of the coprophilic ascomycete fungus Podospora anserina.

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Couturier, Marie; Tangthirasunun, Narumon; Ning, Xie; Brun, Sylvain; Gautier, Valérie; Bennati-Granier, Chloé; Silar, Philippe; Berrin, Jean-Guy

2016-01-01

The degradation of plant biomass is a major challenge towards the production of bio-based compounds and materials. As key lignocellulolytic enzyme producers, filamentous fungi represent a promising reservoir to tackle this challenge. Among them, the coprophilous ascomycete Podospora anserina has been used as a model organism to study various biological mechanisms because its genetics are well understood and controlled. In 2008, the sequencing of its genome revealed a great diversity of enzymes targeting plant carbohydrates and lignin. Since then, a large array of lignocellulose-acting enzymes has been characterized and genetic analyses have enabled the understanding of P. anserina metabolism and development on plant biomass. Overall, these research efforts shed light on P. anserina strategy to unlock recalcitrant lignocellulose deconstruction. Copyright © 2016 Elsevier Inc. All rights reserved.

Biotransformation of Progesterone by the Ascomycete Aspergillus niger N402.

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Savinova, O S; Solyev, P N; Vasina, D V; Tyazhelova, T V; Fedorova, T V; Savinova, T S

2018-01-01

The ability of the ascomycete Aspergillus niger N402 to transform exogenous progesterone was investigated. We found that this strain has steroid-hydroxylating activity and can introduce a hydroxyl group into the progesterone molecule mainly at positions C11(α) and C21 with predominant formation of 21-hydroxyprogesterone (deoxycortone). In addition, formation of 6β,11α-dihydroxyprogesterone was also observed. Studying the effects of the growth medium composition and temperature on progesterone conversion by A. niger N402 showed that the most intense accumulation of 21-hydroxyprogesterone occurred in minimal synthetic medium at 28°C. Increasing the cultivation temperature to 37°C resulted in almost complete inhibition of the hydroxylase activity in the minimal medium. In the complete medium, a similar increase in temperature inhibited 11α-hydroxylase activity and completely suppressed 6β-hydroxylase activity, but it produced no effect on 21-hydroxylating activity.

Production of Ethanol and Biomass from Thin Stillage Using Food-Grade Zygomycetes and Ascomycetes Filamentous Fungi

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Jorge A. Ferreira

2014-06-01

Full Text Available A starch-based ethanol facility producing 200,000 m3 ethanol/year also produces ca. 2 million m3 thin stillage, which can be used to improve the entire process. In this work, five food-grade filamentous fungi, including a Zygomycete and four Ascomycetes were successfully grown in thin stillage containing 9% solids. Cultivation with Neurospora intermedia led to the production of ca. 16 g·L−1 biomass containing 56% (w/w crude protein, a reduction of 34% of the total solids, and 5 g·L−1 additional ethanol. In an industrial ethanol production process (200,000 m3 ethanol/year, this can potentially lead to the production of 11,000 m3 extra ethanol per year. Cultivation with Aspergillus oryzae resulted in 19 g·L−1 biomass containing 48% (w/w crude protein and the highest reduction of the thin stillage glycerol (54% among the Ascomycetes. Cultivation with Rhizopus sp. produced up to 15 g·L−1 biomass containing 55% (w/w crude protein. The spent thin stillage had been reduced up to 85%, 68% and 21% regarding lactic acid, glycerol and total solids, respectively. Therefore, N. intermedia, in particular, has a high potential to improve the ethanol process via production of additional ethanol and high-quality biomass, which can be considered for animal feed applications such as for fish feed.

Bioconversion of (+)-valencene in submerged cultures of the ascomycete Chaetomium globosum.

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Kaspera, Rüdiger; Krings, Ulrich; Nanzad, Tsevegsuren; Berger, Ralf G

2005-06-01

Submerged cultures of the ascomycete Chaetomium globosum oxidised the exogenous sesquiterpene (+)-valencene to nootkatone via the stereoselective generation of alpha-nootkatol. Inhibition experiments suggested that the first introduction of oxygen, the rate-limiting step of the bioconversion, may have been catalysed by a cytochrome-P450-monooxygenase. However, nootkatone was not the final metabolite: further flavour-active and inactive, non-volatile oxidation products were identified. (+)-Valencene and the flavour-active mono-oxyfunctionalised transformation products, alpha-nootkatol, nootkatone, and valencene-11,12-epoxide accumulated preferably inside the fungal cells. Di- and poly-oxygenated products, such as nootkatone-11,12-epoxide, were found solely in the culture medium, indicating an active transport of these metabolites into the extracellular compartment during (+)-valencene detoxification. These metabolic properties may have contributed to the high tolerance of the fungus towards the exogenous hydrocarbon.

A STE12 homologue of the homothallic ascomycete Sordaria macrospora interacts with the MADS box protein MCM1 and is required for ascosporogenesis.

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Nolting, Nicole; Pöggeler, Stefanie

2006-11-01

The MADS box protein MCM1 controls diverse developmental processes and is essential for fruiting body formation in the homothallic ascomycete Sordaria macrospora. MADS box proteins derive their regulatory specificity from a wide range of different protein interactions. We have recently shown that the S. macrospora MCM1 is able to interact with the alpha-domain mating-type protein SMTA-1. To further evaluate the functional roles of MCM1, we used the yeast two-hybrid approach to identify MCM1-interacting proteins. From this screen, we isolated a protein with a putative N-terminal homeodomain and C-terminal C2/H2-Zn2+ finger domains. The protein is a member of the highly conserved fungal STE12 transcription factor family of proteins and was therefore termed STE12. Furthermore, we demonstrate by means of two-hybrid and far western analysis that in addition to MCM1, the S. macrospora STE12 protein is able to interact with the mating-type protein SMTA-1. Unlike the situation in the closely related heterothallic ascomycete Neurospora crassa, deletion (Delta) of the ste12 gene in S. macrospora neither affects vegetative growth nor fruiting body formation. However, ascus and ascospore development are highly impaired by the Deltaste12 mutation. Our data provide another example of the functional divergence within the fungal STE12 transcription factor family.

Biotechnology of non-Saccharomyces yeasts--the ascomycetes.

Science.gov (United States)

Johnson, Eric A

2013-01-01

Saccharomyces cerevisiae and several other yeast species are among the most important groups of biotechnological organisms. S. cerevisiae and closely related ascomycetous yeasts are the major producer of biotechnology products worldwide, exceeding other groups of industrial microorganisms in productivity and economic revenues. Traditional industrial attributes of the S. cerevisiae group include their primary roles in food fermentations such as beers, cider, wines, sake, distilled spirits, bakery products, cheese, sausages, and other fermented foods. Other long-standing industrial processes involving S. cerevisae yeasts are production of fuel ethanol, single-cell protein (SCP), feeds and fodder, industrial enzymes, and small molecular weight metabolites. More recently, non-Saccharomyces yeasts (non-conventional yeasts) have been utilized as industrial organisms for a variety of biotechnological roles. Non-Saccharomyces yeasts are increasingly being used as hosts for expression of proteins, biocatalysts and multi-enzyme pathways for the synthesis of fine chemicals and small molecular weight compounds of medicinal and nutritional importance. Non-Saccharomyces yeasts also have important roles in agriculture as agents of biocontrol, bioremediation, and as indicators of environmental quality. Several of these products and processes have reached commercial utility, while others are in advanced development. The objective of this mini-review is to describe processes currently used by industry and those in developmental stages and close to commercialization primarily from non-Saccharomyces yeasts with an emphasis on new opportunities. The utility of S. cerevisiae in heterologous production of selected products is also described.

Deletion of Smgpi1 encoding a GPI-anchored protein suppresses sterility of the STRIPAK mutant ΔSmmob3 in the filamentous ascomycete Sordaria macrospora.

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Frey, Stefan; Lahmann, Yasmine; Hartmann, Thomas; Seiler, Stephan; Pöggeler, Stefanie

2015-08-01

The striatin interacting phosphatase and kinase (STRIPAK) complex, which is composed of striatin, protein phosphatase PP2A and kinases, is required for fruiting-body development and cell fusion in the filamentous ascomycete Sordaria macrospora. Here, we report on the interplay of the glycosylphosphatidylinositol (GPI)-anchored protein SmGPI1 with the kinase activator SmMOB3, a core component of human and fungal STRIPAK complexes. SmGPI1 is conserved among filamentous ascomycetes and was first identified in a yeast two-hybrid screen using SmMOB3 as bait. The physical interaction of SmMOB3 and SmGPI1 was verified by co-immunoprecipitation. In vivo localization and differential centrifugation revealed that SmGPI1 is predominantly secreted and attached to the cell wall but is also associated with mitochondria and appears to be a dual-targeted protein. Deletion of Smgpi1 led to an increased number of fruiting bodies that were normally shaped but reduced in size. In addition, Smmob3 and Smgpi1 genetically interact. In the sterile ΔSmmob3 background deletion of Smgpi1 restores fertility, vegetative growth as well as hyphal-fusion defects. The suppression effect was specific for the ΔSmmob3 mutant as deletion of Smgpi1 in other STRIPAK mutants does not restore fertility. © 2015 John Wiley & Sons Ltd.

Production and New Extraction Method of Polyketide Red Pigments Produced by Ascomycetous Fungi from Terrestrial and Marine Habitats.

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Lebeau, Juliana; Venkatachalam, Mekala; Fouillaud, Mireille; Petit, Thomas; Vinale, Francesco; Dufossé, Laurent; Caro, Yanis

2017-06-28

The use of ascomycetous fungi as pigment producers opens the way to an alternative to synthetic dyes, especially in the red-dye industries, which have very few natural pigment alternatives. The present paper aimed to bio-prospect and screen out 15 selected ascomycetous fungal strains, originating from terrestrial and marine habitats belonging to seven different genera ( Penicillium , Talaromyces , Fusarium , Aspergillus , Trichoderma , Dreschlera , and Paecilomyces ). We identified four strains, Penicillium purpurogenum rubisclerotium , Fusarium oxysporum , marine strains identified as Talaromyces spp., and Trichoderma atroviride , as potential red pigment producers. The extraction of the pigments is a crucial step, whereby the qualitative and quantitative compositions of each fungal extract need to be respected for reliable identification, as well as preserving bioactivity. Furthermore, there is a growing demand for more sustainable and cost-effective extraction methods. Therefore, a pressurized liquid extraction technique was carried out in this study, allowing a greener and faster extraction step of the pigments, while preserving their chemical structures and bioactivities in comparison to conventional extraction processes. The protocol was illustrated with the production of pigment extracts from P. purpurogenum rubisclerotium and Talaromyces spp. Extracts were analyzed by high-performance liquid-chromatography combined with photodiode array-detection (HPLC-DAD) and high-resolution mass spectrometry (UHPLC-HRMS). The more promising strain was the isolate Talaromyces spp. of marine origin. The main polyketide pigment produced by this strain has been characterized as N -threoninerubropunctamine, a non-toxic red Monascus -like azaphilone pigment.

Autophagic kinases SmVPS34 and SmVPS15 are required for viability in the filamentous ascomycete Sordaria macrospora.

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Voigt, Oliver; Herzog, Britta; Jakobshagen, Antonia; Pöggeler, Stefanie

2014-01-01

Autophagy is a tightly controlled degradation process of all eukaryotes. It includes the sequestration of cytoplasmic contents and organelles within a double-membraned autophagosome. Autophagy involves core autophagy related (atg) genes as well as genes regulating vesicle trafficking. Previously, we analyzed the impact of proteins of the core autophagic machinery SmATG7, SmATG8 and SmATG4 on the sexual and vegetative development of the filamentous ascomycete Sordaria macrospora. While deletion of Smatg8 and Smatg4 abolished fruiting-body formation and impaired vegetative growth, Smatg7 is required for viability. In yeast, the phosphatidylinositol 3-kinase vacuolar protein sorting 34 (Vps34) and its myristoylated membrane targeting unit, the protein kinase Vps15 have been shown to be important regulators of autophagy and vacuolar protein sorting. However, their exact role in filamentous ascomycetes remains elusive. To determine the function of Smvps34 and Smvps15 we isolated genes with high sequence similarity to Saccharomyces cerevisiae VPS34 and VPS15. For both genes we were not able to generate a homokaryotic knockout mutant in S. macrospora, suggesting that Smvps34 and Smvps15 are required for viability. Furthermore, we analyzed the repertoire of vps genes encoded by S. macrospora and could identify putative homologs of nearly all of the 61 VPS genes of S. cerevisiae. Copyright © 2013 Elsevier GmbH. All rights reserved.

When a Plant Resistance Inducer Leaves the Lab for the Field: Integrating ASM into Routine Apple Protection Practices.

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Marolleau, Brice; Gaucher, Matthieu; Heintz, Christelle; Degrave, Alexandre; Warneys, Romain; Orain, Gilles; Lemarquand, Arnaud; Brisset, Marie-Noëlle

2017-01-01

Plant resistance inducers, also called elicitors, could be useful to reduce the use of pesticides. However, their performance in controlling diseases in the field remains unsatisfactory due to lack of specific knowledge of how they can integrate crop protection practices. In this work, we focused on apple crop and acibenzolar- S -methyl (ASM), a well-known SAR (systemic acquired resistance) inducer of numerous plant species. We provide a protocol for orchard-effective control of apple scab due to the ascomycete fungus Venturia inaequalis , by applying ASM in combination with a light integrated pest management program. Besides we pave the way for future optimization levers by demonstrating in controlled conditions (i) the high influence of apple genotypes, (ii) the ability of ASM to prime defenses in newly formed leaves, (iii) the positive effect of repeated elicitor applications, (iv) the additive effect of a thinning fruit agent.

Waste biorefineries using filamentous ascomycetes fungi: Present status and future prospects.

Science.gov (United States)

Ferreira, Jorge A; Mahboubi, Amir; Lennartsson, Patrik R; Taherzadeh, Mohammad J

2016-09-01

Filamentous ascomycetes fungi have had important roles in natural cycles, and are already used industrially for e.g. supplying of citric, gluconic and itaconic acids as well as many enzymes. Faster human activities result in higher consumption of our resources and producing more wastes. Therefore, these fungi can be explored to use their capabilities to convert back wastes to resources. The present paper reviews the capabilities of these fungi in growing on various residuals, producing lignocellulose-degrading enzymes and production of organic acids, ethanol, pigments, etc. Particular attention has been on Aspergillus, Fusarium, Neurospora and Monascus genera. Since various species are used for production of human food, their biomass can be considered for feed applications and so biomass compositional characteristics as well as aspects related to culture in bioreactor are also provided. The review has been further complemented with future research avenues. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Candida neustonensis sp. nov., a novel ascomycetous yeast isolated from the sea surface microlayer in Taiwan.

Science.gov (United States)

Chang, Chin-Feng; Lee, Ching-Fu; Liu, Shiu-Mei

2010-01-01

A new ascomycetous yeast species, Candida neustonensis is proposed in this study based on four strains (SN92(T), SN47, SJ22, SJ25) isolated from sea surface microlayer in Taiwan. These four yeast strains were morphologically, physiologically and phylogenetically identical to each other. No sexual reproduction was observed on 5% malt extract agar, corn meal agar, V8 agar, McClary's acetate agar and potato-dextrose agar. Phylogenetic analysis of the sequences of the D1/D2 domain of the large subunit (LSU) rRNA gene places C. neustonensis as a member of the Pichia guilliermondii clade, it also reveals that the phylogenetically closest relatives of C. neustonensis are C. fukuyamaensis (4.4% divergence), C. xestobii (4.4% divergence) and P. guilliermondii (4.5% divergence). C. neustonensis also is clearly distinguished from other known species in the P. guilliermondii clade based on the results of physiology tests. From these comparison analyses, the following novel yeast species is proposed: Candida neustonensis sp. nov., with strain SN92(T) (= BCRC 23108(T) = JCM 14892(T) = CBS 11061(T)) as the type strain.

PaTrx1 and PaTrx3, two cytosolic thioredoxins of the filamentous ascomycete Podospora anserina involved in sexual development and cell degeneration.

Science.gov (United States)

Malagnac, Fabienne; Klapholz, Benjamin; Silar, Philippe

2007-12-01

In various organisms, thioredoxins are known to be involved in the reduction of protein disulfide bonds and in protecting the cell from oxidative stress. Genes encoding thioredoxins were found by searching the complete genome sequence of the filamentous ascomycete Podospora anserina. Among them, PaTrx1, PaTrx2, and PaTrx3 are predicted to be canonical cytosolic proteins without additional domains. Targeted disruption of PaTrx1, PaTrx2, and PaTrx3 shows that PaTrx1 is the major thioredoxin involved in sulfur metabolism. Deletions have no effect on peroxide resistance; however, data show that either PaTrx1 or PaTrx3 is necessary for sexual reproduction and for the development of the crippled growth cell degeneration (CG), processes that also required the PaMpk1 mitogen-activated protein kinase (MAPK) pathway. Since PaTrx1 PaTrx3 mutants show not an enhancement but rather an impairment in CG, it seems unlikely that PaTrx1 and PaTrx3 thioredoxins participate in the inhibition of this MAPK pathway. Altogether, these results underscore a role for thioredoxins in fungal development.

Valorization of sugar-to-ethanol process waste vinasse: A novel biorefinery approach using edible ascomycetes filamentous fungi.

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Nair, Ramkumar B; Taherzadeh, Mohammad J

2016-12-01

The aim of the present work was to study the integration of edible ascomycetes filamentous fungi into the existing sugar- or molasses-to-ethanol processes, to grow on vinasse or stillage and produce ethanol and protein-rich fungal biomass. Two fungal strains, Neurospora intermedia and Aspergillus oryzae were examined in shake flasks and airlift-bioreactors, resulting in reduction of vinasse COD by 34% and viscosity by 21%. Utilization of glycerol and sugars were observed, yielding 202.4 or 222.8g dry fungal biomass of N. intermedia or A. oryzae respectively, per liter of vinasse. Integration of the current process at an existing ethanol facility producing about 100,000m 3 of ethanol per year could produce around 200,000-250,000tons of dry fungal biomass (40-45% protein) together with about 8800-12,600m 3 extra ethanol (8.8-12.6% of production-rate improvement). Copyright © 2016 Elsevier Ltd. All rights reserved.

Autophagy-Associated Protein SmATG12 Is Required for Fruiting-Body Formation in the Filamentous Ascomycete Sordaria macrospora.

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Werner, Antonia; Herzog, Britta; Frey, Stefan; Pöggeler, Stefanie

2016-01-01

In filamentous fungi, autophagy functions as a catabolic mechanism to overcome starvation and to control diverse developmental processes under normal nutritional conditions. Autophagy involves the formation of double-membrane vesicles, termed autophagosomes that engulf cellular components and bring about their degradation via fusion with vacuoles. Two ubiquitin-like (UBL) conjugation systems are essential for the expansion of the autophagosomal membrane: the UBL protein ATG8 is conjugated to the lipid phosphatidylethanolamine and the UBL protein ATG12 is coupled to ATG5. We recently showed that in the homothallic ascomycete Sordaria macrospora autophagy-related genes encoding components of the conjugation systems are required for fruiting-body development and/or are essential for viability. In the present work, we cloned and characterized the S. macrospora (Sm)atg12 gene. Two-hybrid analysis revealed that SmATG12 can interact with SmATG7 and SmATG3. To examine its role in S. macrospora, we replaced the open reading frame of Smatg12 with a hygromycin resistance cassette and generated a homokaryotic ΔSmatg12 knockout strain, which displayed slower vegetative growth under nutrient starvation conditions and was unable to form fruiting bodies. In the hyphae of S. macrospora EGFP-labeled SmATG12 was detected in the cytoplasm and as punctate structures presumed to be phagophores or phagophore assembly sites. Delivery of EGFP-labelled SmATG8 to the vacuole was entirely dependent on SmATG12.

Autophagy-Associated Protein SmATG12 Is Required for Fruiting-Body Formation in the Filamentous Ascomycete Sordaria macrospora.

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Antonia Werner

Full Text Available In filamentous fungi, autophagy functions as a catabolic mechanism to overcome starvation and to control diverse developmental processes under normal nutritional conditions. Autophagy involves the formation of double-membrane vesicles, termed autophagosomes that engulf cellular components and bring about their degradation via fusion with vacuoles. Two ubiquitin-like (UBL conjugation systems are essential for the expansion of the autophagosomal membrane: the UBL protein ATG8 is conjugated to the lipid phosphatidylethanolamine and the UBL protein ATG12 is coupled to ATG5. We recently showed that in the homothallic ascomycete Sordaria macrospora autophagy-related genes encoding components of the conjugation systems are required for fruiting-body development and/or are essential for viability. In the present work, we cloned and characterized the S. macrospora (Smatg12 gene. Two-hybrid analysis revealed that SmATG12 can interact with SmATG7 and SmATG3. To examine its role in S. macrospora, we replaced the open reading frame of Smatg12 with a hygromycin resistance cassette and generated a homokaryotic ΔSmatg12 knockout strain, which displayed slower vegetative growth under nutrient starvation conditions and was unable to form fruiting bodies. In the hyphae of S. macrospora EGFP-labeled SmATG12 was detected in the cytoplasm and as punctate structures presumed to be phagophores or phagophore assembly sites. Delivery of EGFP-labelled SmATG8 to the vacuole was entirely dependent on SmATG12.

The ura5 gene of the ascomycete Sordaria macrospora: molecular cloning, characterization and expression in Escherichia coli.

Science.gov (United States)

Le Chevanton, L; Leblon, G

1989-04-15

We cloned the ura5 gene coding for the orotate phosphoribosyl transferase from the ascomycete Sordaria macrospora by heterologous probing of a Sordaria genomic DNA library with the corresponding Podospora anserina sequence. The Sordaria gene was expressed in an Escherichia coli pyrE mutant strain defective for the same enzyme, and expression was shown to be promoted by plasmid sequences. The nucleotide sequence of the 1246-bp DNA fragment encompassing the region of homology with the Podospora gene has been determined. This sequence contains an open reading frame of 699 nucleotides. The deduced amino acid sequence shows 72% similarity with the corresponding Podospora protein.

PaTrx1 and PaTrx3, Two Cytosolic Thioredoxins of the Filamentous Ascomycete Podospora anserina Involved in Sexual Development and Cell Degeneration▿ †

Science.gov (United States)

Malagnac, Fabienne; Klapholz, Benjamin; Silar, Philippe

2007-01-01

In various organisms, thioredoxins are known to be involved in the reduction of protein disulfide bonds and in protecting the cell from oxidative stress. Genes encoding thioredoxins were found by searching the complete genome sequence of the filamentous ascomycete Podospora anserina. Among them, PaTrx1, PaTrx2, and PaTrx3 are predicted to be canonical cytosolic proteins without additional domains. Targeted disruption of PaTrx1, PaTrx2, and PaTrx3 shows that PaTrx1 is the major thioredoxin involved in sulfur metabolism. Deletions have no effect on peroxide resistance; however, data show that either PaTrx1 or PaTrx3 is necessary for sexual reproduction and for the development of the crippled growth cell degeneration (CG), processes that also required the PaMpk1 mitogen-activated protein kinase (MAPK) pathway. Since PaTrx1 PaTrx3 mutants show not an enhancement but rather an impairment in CG, it seems unlikely that PaTrx1 and PaTrx3 thioredoxins participate in the inhibition of this MAPK pathway. Altogether, these results underscore a role for thioredoxins in fungal development. PMID:17933907

Autophagy genes Smatg8 and Smatg4 are required for fruiting-body development, vegetative growth and ascospore germination in the filamentous ascomycete Sordaria macrospora.

Science.gov (United States)

Voigt, Oliver; Pöggeler, Stefanie

2013-01-01

Autophagy is a tightly controlled degradation process involved in various developmental aspects of eukaryotes. However, its involvement in developmental processes of multicellular filamentous ascomycetes is largely unknown. Here, we analyzed the impact of the autophagic proteins SmATG8 and SmATG4 on the sexual and vegetative development of the filamentous ascomycete Sordaria macrospora. A Saccharomyces cerevisiae complementation assay demonstrated that the S. macrospora Smatg8 and Smatg4 genes can functionally replace the yeast homologs. By generating homokaryotic deletion mutants, we showed that the S. macrospora SmATG8 and SmATG4 orthologs were associated with autophagy-dependent processes. Smatg8 and Smatg4 deletions abolished fruiting-body formation and impaired vegetative growth and ascospore germination, but not hyphal fusion. We demonstrated that SmATG4 was capable of processing the SmATG8 precursor. SmATG8 was localized to autophagosomes, whereas SmATG4 was distributed throughout the cytoplasm of S. macrospora. Furthermore, we could show that Smatg8 and Smatg4 are not only required for nonselective macroautophagy, but for selective macropexophagy as well. Taken together, our results suggest that in S. macrospora, autophagy seems to be an essential and constitutively active process to sustain high energy levels for filamentous growth and multicellular development even under nonstarvation conditions.

Functional characterization of MAT1-1-specific mating-type genes in the homothallic ascomycete Sordaria macrospora provides new insights into essential and nonessential sexual regulators.

Science.gov (United States)

Klix, V; Nowrousian, M; Ringelberg, C; Loros, J J; Dunlap, J C; Pöggeler, S

2010-06-01

Mating-type genes in fungi encode regulators of mating and sexual development. Heterothallic ascomycete species require different sets of mating-type genes to control nonself-recognition and mating of compatible partners of different mating types. Homothallic (self-fertile) species also carry mating-type genes in their genome that are essential for sexual development. To analyze the molecular basis of homothallism and the role of mating-type genes during fruiting-body development, we deleted each of the three genes, SmtA-1 (MAT1-1-1), SmtA-2 (MAT1-1-2), and SmtA-3 (MAT1-1-3), contained in the MAT1-1 part of the mating-type locus of the homothallic ascomycete species Sordaria macrospora. Phenotypic analysis of deletion mutants revealed that the PPF domain protein-encoding gene SmtA-2 is essential for sexual reproduction, whereas the alpha domain protein-encoding genes SmtA-1 and SmtA-3 play no role in fruiting-body development. By means of cross-species microarray analysis using Neurospora crassa oligonucleotide microarrays hybridized with S. macrospora targets and quantitative real-time PCR, we identified genes expressed under the control of SmtA-1 and SmtA-2. Both genes are involved in the regulation of gene expression, including that of pheromone genes.

Anilinopyrimidine Resistance in Botrytis cinerea Is Linked to Mitochondrial Function

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Andreas Mosbach

2017-11-01

Full Text Available Crop protection anilinopyrimidine (AP fungicides were introduced more than 20 years ago for the control of a range of diseases caused by ascomycete plant pathogens, and in particular for the control of gray mold caused by Botrytis cinerea. Although early mode of action studies suggested an inhibition of methionine biosynthesis, the molecular target of this class of fungicides was never fully clarified. Despite AP-specific resistance having been described in B. cinerea field isolates and in multiple other targeted species, the underlying resistance mechanisms were unknown. It was therefore expected that the genetic characterization of resistance mechanisms would permit the identification of the molecular target of these fungicides. In order to explore the widest range of possible resistance mechanisms, AP-resistant B. cinerea UV laboratory mutants were generated and the mutations conferring resistance were determined by combining whole-genome sequencing and reverse genetics. Genetic mapping from a cross between a resistant field isolate and a sensitive reference isolate was used in parallel and led to the identification of an additional molecular determinant not found from the characterized UV mutant collection. Together, these two approaches enabled the characterization of an unrivaled diversity of resistance mechanisms. In total, we report the elucidation of resistance-conferring mutations within nine individual genes, two of which are responsible for almost all instances of AP resistance in the field. All identified resistance-conferring genes encode proteins that are involved in mitochondrial processes, suggesting that APs primarily target the mitochondria. The functions of these genes and their possible interactions are discussed in the context of the potential mode of action for this important class of fungicides.

Mycelial pellet formation by edible ascomycete filamentous fungi, Neurospora intermedia.

Science.gov (United States)

Nair, Ramkumar B; Lennartsson, Patrik R; Taherzadeh, Mohammad J

2016-12-01

Pellet formation of filamentous fungi in submerged culture is an imperative topic of fermentation research. In this study, we report for the first time the growth of filamentous ascomycete fungus, Neurospora intermedia in its mycelial pellet form. In submerged culture, the growth morphology of the fungus was successfully manipulated into growing as pellets by modifying various cultivation conditions. Factors such as pH (2.0-10.0), agitation rate (100-150 rpm), carbon source (glucose, arabinose, sucrose, and galactose), the presence of additive agents (glycerol and calcium chloride) and trace metals were investigated for their effect on the pellet formation. Of the various factors screened, uniform pellets were formed only at pH range 3.0-4.0, signifying it as the most influential factor for N. intermedia pellet formation. The average pellet size ranged from 2.38 ± 0.12 to 2.86 ± 0.38 mm. The pellet formation remained unaffected by the inoculum type used and its size showed an inverse correlation with the agitation rate of the culture. Efficient glucose utilization was observed with fungal pellets, as opposed to the freely suspended mycelium, proving its viability for fast-fermentation processes. Scale up of the pelletization process was also carried out in bench-scale airlift and bubble column reactors (4.5 L).

Functional Characterization of MAT1-1-Specific Mating-Type Genes in the Homothallic Ascomycete Sordaria macrospora Provides New Insights into Essential and Nonessential Sexual Regulators▿†

Science.gov (United States)

Klix, V.; Nowrousian, M.; Ringelberg, C.; Loros, J. J.; Dunlap, J. C.; Pöggeler, S.

2010-01-01

Mating-type genes in fungi encode regulators of mating and sexual development. Heterothallic ascomycete species require different sets of mating-type genes to control nonself-recognition and mating of compatible partners of different mating types. Homothallic (self-fertile) species also carry mating-type genes in their genome that are essential for sexual development. To analyze the molecular basis of homothallism and the role of mating-type genes during fruiting-body development, we deleted each of the three genes, SmtA-1 (MAT1-1-1), SmtA-2 (MAT1-1-2), and SmtA-3 (MAT1-1-3), contained in the MAT1-1 part of the mating-type locus of the homothallic ascomycete species Sordaria macrospora. Phenotypic analysis of deletion mutants revealed that the PPF domain protein-encoding gene SmtA-2 is essential for sexual reproduction, whereas the α domain protein-encoding genes SmtA-1 and SmtA-3 play no role in fruiting-body development. By means of cross-species microarray analysis using Neurospora crassa oligonucleotide microarrays hybridized with S. macrospora targets and quantitative real-time PCR, we identified genes expressed under the control of SmtA-1 and SmtA-2. Both genes are involved in the regulation of gene expression, including that of pheromone genes. PMID:20435701

Genetics of Resistance and Pathogenicity in the Maize/Setosphaeria turcica Pathosystem and Implications for Breeding

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Ana L. Galiano-Carneiro

2017-08-01

Full Text Available Northern corn leaf blight (NCLB, the most devastating leaf pathogen in maize (Zea mays L., is caused by the heterothallic ascomycete Setosphaeria turcica. The pathogen population shows an extremely high genetic diversity in tropical and subtropical regions. Varietal resistance is the most efficient technique to control NCLB. Host resistance can be qualitative based on race-specific Ht genes or quantitative controlled by many genes with small effects. Quantitative resistance is moderately to highly effective and should be more durable combatting all races of the pathogen. Quantitative resistance must, however, be analyzed in many environments (= location × year combinations to select stable resistances. In the tropical and subtropical environments, quantitative resistance is the preferred option to manage NCLB epidemics. Resistance level can be increased in practical breeding programs by several recurrent selection cycles based on disease severity rating and/or by genomic selection. This review aims to address two important aspects of the NCLB pathosystem: the genetics of the fungus S. turcica and the modes of inheritance of the host plant maize, including successful breeding strategies regarding NCLB resistance. Both drivers of this pathosystem, pathogen, and host, must be taken into account to result in more durable resistance.

Mating-type genes from the homothallic fungus Sordaria macrospora are functionally expressed in a heterothallic ascomycete.

Science.gov (United States)

Pöggeler, S; Risch, S; Kück, U; Osiewacz, H D

1997-10-01

Homokaryons from the homothallic ascomycte Sordaria macrospora are able to enter the sexual pathway and to form fertile fruiting bodies. To analyze the molecular basis of homothallism and to elucidate the role of mating-products during fruiting body development, we cloned and sequenced the entire S. macrospora mating-type locus. Comparison of the Sordaria mating-type locus with mating-type idiomorphs from the heterothallic ascomycetes Neurospora crassa and Podospora anserina revealed that sequences from both idiomorphs (A/a and mat-/mat+, respectively) are contiguous in S. macrospora. DNA sequencing of the S. macrospora mating-type region allowed the identification of four open reading frames (ORFs), which were termed Smt-a1, SmtA-1, SmtA-2 and SmtA-3. While Smt-a1, SmtA-1, and SmtA-2 show strong sequence similarities with the corresponding N. crassa mating-type ORFs, SmtA-3 has a chimeric character. It comprises sequences that are similar to the A and a mating-type idiomorph from N. crassa. To determine functionality of the S. macrospora mating-type genes, we show that all ORFs are transcriptionally expressed. Furthermore, we transformed the S. macrospora mating-type genes into mat- and mat+ strains of the closely related heterothallic fungus P. anserina. The transformation experiments show that mating-type genes from S. macrospora induce fruiting body formation in P. anserina.

Quantitative iTRAQ-based secretome analysis reveals species-specific and temporal shifts in carbon utilization strategies among manganese(II)-oxidizing Ascomycete fungi

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Zeiner, Carolyn A.; Purvine, Samuel O.; Zink, Erika M.; Paša-Tolić, Ljiljana; Chaput, Dominique L.; Wu, Si; Santelli, Cara M.; Hansel, Colleen M.

2017-09-01

Fungi generate a wide range of extracellular hydrolytic and oxidative enzymes and reactive metabolites, collectively known as the secretome, that synergistically drive plant litter decomposition in the environment. While secretome studies of model organisms have greatly expanded our knowledge of these enzymes, few have extended secretome characterization to environmental isolates or directly compared temporal patterns of enzyme utilization among diverse species. Thus, the mechanisms of carbon (C) degradation by many ubiquitous soil fungi remain poorly understood. Here we use a combination of iTRAQ proteomics and custom bioinformatic analyses to compare the protein composition of the secretomes of four manganese(II)-oxidizing Ascomycete fungi over a three-week time course. We demonstrate that although the fungi produce a similar suite of extracellular enzymes, they exhibit striking differences in the regulation of these enzymes among species and over time, revealing species-specific and temporal shifts in C utilization strategies as they degrade the same substrate. Specifically, our findings suggest that Paraconiothyrium sporulosum AP3s5-JAC2a and Alternaria alternata SRC1lrK2f employ sequential enzyme secretion patterns concomitant with decreasing resource availability, Stagonospora sp. SRC1lsM3a preferentially degrades proteinaceous substrate before switching to carbohydrates, and Pyrenochaeta sp. DS3sAY3a utilizes primarily peptidases to aggressively attack carbon sources in a concentrated burst. This work highlights the diversity of operative metabolic strategies among cellulose-degrading Ascomycetes and enhances our understanding of their role in C turnover in the environment.

Contrasting diversity and host association of ectomycorrhizal basidiomycetes versus root-associated ascomycetes in a dipterocarp rainforest.

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Hirotoshi Sato

Full Text Available Root-associated fungi, including ectomycorrhizal and root-endophytic fungi, are among the most diverse and important belowground plant symbionts in dipterocarp rainforests. Our study aimed to reveal the biodiversity, host association, and community structure of ectomycorrhizal Basidiomycota and root-associated Ascomycota (including root-endophytic Ascomycota in a lowland dipterocarp rainforest in Southeast Asia. The host plant chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit (rbcL region and fungal internal transcribed spacer 2 (ITS2 region were sequenced using tag-encoded, massively parallel 454 pyrosequencing to identify host plant and root-associated fungal taxa in root samples. In total, 1245 ascomycetous and 127 putative ectomycorrhizal basidiomycetous taxa were detected from 442 root samples. The putative ectomycorrhizal Basidiomycota were likely to be associated with closely related dipterocarp taxa to greater or lesser extents, whereas host association patterns of the root-associated Ascomycota were much less distinct. The community structure of the putative ectomycorrhizal Basidiomycota was possibly more influenced by host genetic distances than was that of the root-associated Ascomycota. This study also indicated that in dipterocarp rainforests, root-associated Ascomycota were characterized by high biodiversity and indistinct host association patterns, whereas ectomycorrhizal Basidiomycota showed less biodiversity and a strong host phylogenetic preference for dipterocarp trees. Our findings lead to the working hypothesis that root-associated Ascomycota, which might be mainly represented by root-endophytic fungi, have biodiversity hotspots in the tropics, whereas biodiversity of ectomycorrhizal Basidiomycota increases with host genetic diversity.

Effect of the L499M mutation of the ascomycetous Botrytis aclada laccase on redox potential and catalytic properties

International Nuclear Information System (INIS)

Osipov, Evgeny; Polyakov, Konstantin; Kittl, Roman; Shleev, Sergey; Dorovatovsky, Pavel; Tikhonova, Tamara; Hann, Stephan; Ludwig, Roland; Popov, Vladimir

2014-01-01

The structures of the ascomycetous B. aclada laccase and its L499M T1-site mutant have been solved at 1.7 Å resolution. The mutant enzyme shows a 140 mV lower redox potential of the type 1 copper and altered kinetic behaviour. The wild type and the mutant have very similar structures, which makes it possible to relate the changes in the redox potential to the L499M mutation Laccases are members of a large family of multicopper oxidases that catalyze the oxidation of a wide range of organic and inorganic substrates accompanied by the reduction of dioxygen to water. These enzymes contain four Cu atoms per molecule organized into three sites: T1, T2 and T3. In all laccases, the T1 copper ion is coordinated by two histidines and one cysteine in the equatorial plane and is covered by the side chains of hydrophobic residues in the axial positions. The redox potential of the T1 copper ion influences the enzymatic reaction and is determined by the nature of the axial ligands and the structure of the second coordination sphere. In this work, the laccase from the ascomycete Botrytis aclada was studied, which contains conserved Ile491 and nonconserved Leu499 residues in the axial positions. The three-dimensional structures of the wild-type enzyme and the L499M mutant were determined by X-ray crystallography at 1.7 Å resolution. Crystals suitable for X-ray analysis could only be grown after deglycosylation. Both structures did not contain the T2 copper ion. The catalytic properties of the enzyme were characterized and the redox potentials of both enzyme forms were determined: E 0 = 720 and 580 mV for the wild-type enzyme and the mutant, respectively. Since the structures of the wild-type and mutant forms are very similar, the change in the redox potential can be related to the L499M mutation in the T1 site of the enzyme

Sunlight-exposed biofilm microbial communities are naturally resistant to chernobyl ionizing-radiation levels.

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Marie Ragon

Full Text Available BACKGROUND: The Chernobyl accident represents a long-term experiment on the effects of exposure to ionizing radiation at the ecosystem level. Though studies of these effects on plants and animals are abundant, the study of how Chernobyl radiation levels affect prokaryotic and eukaryotic microbial communities is practically non-existent, except for a few reports on human pathogens or soil microorganisms. Environments enduring extreme desiccation and UV radiation, such as sunlight exposed biofilms could in principle select for organisms highly resistant to ionizing radiation as well. METHODOLOGY/PRINCIPAL FINDINGS: To test this hypothesis, we explored the diversity of microorganisms belonging to the three domains of life by cultivation-independent approaches in biofilms developing on concrete walls or pillars in the Chernobyl area exposed to different levels of radiation, and we compared them with a similar biofilm from a non-irradiated site in Northern Ireland. Actinobacteria, Alphaproteobacteria, Bacteroidetes, Acidobacteria and Deinococcales were the most consistently detected bacterial groups, whereas green algae (Chlorophyta and ascomycete fungi (Ascomycota dominated within the eukaryotes. Close relatives to the most radio-resistant organisms known, including Rubrobacter species, Deinococcales and melanized ascomycete fungi were always detected. The diversity of bacteria and eukaryotes found in the most highly irradiated samples was comparable to that of less irradiated Chernobyl sites and Northern Ireland. However, the study of mutation frequencies in non-coding ITS regions versus SSU rRNA genes in members of a same actinobacterial operational taxonomic unit (OTU present in Chernobyl samples and Northern Ireland showed a positive correlation between increased radiation and mutation rates. CONCLUSIONS/SIGNIFICANCE: Our results show that biofilm microbial communities in the most irradiated samples are comparable to non-irradiated samples in

Sunlight-exposed biofilm microbial communities are naturally resistant to chernobyl ionizing-radiation levels.

Science.gov (United States)

Ragon, Marie; Restoux, Gwendal; Moreira, David; Møller, Anders Pape; López-García, Purificación

2011-01-01

The Chernobyl accident represents a long-term experiment on the effects of exposure to ionizing radiation at the ecosystem level. Though studies of these effects on plants and animals are abundant, the study of how Chernobyl radiation levels affect prokaryotic and eukaryotic microbial communities is practically non-existent, except for a few reports on human pathogens or soil microorganisms. Environments enduring extreme desiccation and UV radiation, such as sunlight exposed biofilms could in principle select for organisms highly resistant to ionizing radiation as well. To test this hypothesis, we explored the diversity of microorganisms belonging to the three domains of life by cultivation-independent approaches in biofilms developing on concrete walls or pillars in the Chernobyl area exposed to different levels of radiation, and we compared them with a similar biofilm from a non-irradiated site in Northern Ireland. Actinobacteria, Alphaproteobacteria, Bacteroidetes, Acidobacteria and Deinococcales were the most consistently detected bacterial groups, whereas green algae (Chlorophyta) and ascomycete fungi (Ascomycota) dominated within the eukaryotes. Close relatives to the most radio-resistant organisms known, including Rubrobacter species, Deinococcales and melanized ascomycete fungi were always detected. The diversity of bacteria and eukaryotes found in the most highly irradiated samples was comparable to that of less irradiated Chernobyl sites and Northern Ireland. However, the study of mutation frequencies in non-coding ITS regions versus SSU rRNA genes in members of a same actinobacterial operational taxonomic unit (OTU) present in Chernobyl samples and Northern Ireland showed a positive correlation between increased radiation and mutation rates. Our results show that biofilm microbial communities in the most irradiated samples are comparable to non-irradiated samples in terms of general diversity patterns, despite increased mutation levels at the single

Sunlight-Exposed Biofilm Microbial Communities Are Naturally Resistant to Chernobyl Ionizing-Radiation Levels

Science.gov (United States)

Ragon, Marie; Restoux, Gwendal; Moreira, David; Møller, Anders Pape; López-García, Purificación

2011-01-01

Background The Chernobyl accident represents a long-term experiment on the effects of exposure to ionizing radiation at the ecosystem level. Though studies of these effects on plants and animals are abundant, the study of how Chernobyl radiation levels affect prokaryotic and eukaryotic microbial communities is practically non-existent, except for a few reports on human pathogens or soil microorganisms. Environments enduring extreme desiccation and UV radiation, such as sunlight exposed biofilms could in principle select for organisms highly resistant to ionizing radiation as well. Methodology/Principal Findings To test this hypothesis, we explored the diversity of microorganisms belonging to the three domains of life by cultivation-independent approaches in biofilms developing on concrete walls or pillars in the Chernobyl area exposed to different levels of radiation, and we compared them with a similar biofilm from a non-irradiated site in Northern Ireland. Actinobacteria, Alphaproteobacteria, Bacteroidetes, Acidobacteria and Deinococcales were the most consistently detected bacterial groups, whereas green algae (Chlorophyta) and ascomycete fungi (Ascomycota) dominated within the eukaryotes. Close relatives to the most radio-resistant organisms known, including Rubrobacter species, Deinococcales and melanized ascomycete fungi were always detected. The diversity of bacteria and eukaryotes found in the most highly irradiated samples was comparable to that of less irradiated Chernobyl sites and Northern Ireland. However, the study of mutation frequencies in non-coding ITS regions versus SSU rRNA genes in members of a same actinobacterial operational taxonomic unit (OTU) present in Chernobyl samples and Northern Ireland showed a positive correlation between increased radiation and mutation rates. Conclusions/Significance Our results show that biofilm microbial communities in the most irradiated samples are comparable to non-irradiated samples in terms of general

PaTrx1 and PaTrx3, Two Cytosolic Thioredoxins of the Filamentous Ascomycete Podospora anserina Involved in Sexual Development and Cell Degeneration▿ †

OpenAIRE

Malagnac, Fabienne; Klapholz, Benjamin; Silar, Philippe

2007-01-01

In various organisms, thioredoxins are known to be involved in the reduction of protein disulfide bonds and in protecting the cell from oxidative stress. Genes encoding thioredoxins were found by searching the complete genome sequence of the filamentous ascomycete Podospora anserina. Among them, PaTrx1, PaTrx2, and PaTrx3 are predicted to be canonical cytosolic proteins without additional domains. Targeted disruption of PaTrx1, PaTrx2, and PaTrx3 shows that PaTrx1 is the major thioredoxin inv...

American Peptide Symposium Proceedings (13th) Held in Edmonton, Alberta, Canada on June 20-25, 1993. Peptides: Chemistry, Structure and Biology

Science.gov (United States)

1993-06-20

protein . rceloMEIS w-mdeimidobenzol UtMA I,-Nfoer N-hydroxy- SONaY succinimide ester iniraioa units 14CM melanin concentrating luM keyhole limpet MCPSA...cyclic depsipeptide aureobasidin A (1), isolated as a major component from the culture medium of the black yeast Aureobasidium puUukans R 106, exhibits

Functional properties and differential mode of regulation of the nitrate transporter from a plant symbiotic ascomycete

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Montanini, Barbara; Viscomi, Arturo R.; Bolchi, Angelo; Martin, Yusé; Siverio, José M.; Balestrini, Raffaella; Bonfante, Paola; Ottonello, Simone

2005-01-01

Nitrogen assimilation by plant symbiotic fungi plays a central role in the mutualistic interaction established by these organisms, as well as in nitrogen flux in a variety of soils. In the present study, we report on the functional properties, structural organization and distinctive mode of regulation of TbNrt2 (Tuber borchii NRT2 family transporter), the nitrate transporter of the mycorrhizal ascomycete T. borchii. As revealed by experiments conducted in a nitrate-uptake-defective mutant of the yeast Hansenula polymorpha, TbNrt2 is a high-affinity transporter (Km=4.7 μM nitrate) that is bispecific for nitrate and nitrite. It is expressed in free-living mycelia and in mycorrhizae, where it preferentially accumulates in the plasma membrane of root-contacting hyphae. The TbNrt2 mRNA, which is transcribed from a single-copy gene clustered with the nitrate reductase gene in the T. borchii genome, was specifically up-regulated following transfer of mycelia to nitrate- (or nitrite)-containing medium. However, at variance with the strict nitrate-dependent induction commonly observed in other organisms, TbNrt2 was also up-regulated (at both the mRNA and the protein level) following transfer to a nitrogen-free medium. This unusual mode of regulation differs from that of the adjacent nitrate reductase gene, which was expressed at basal levels under nitrogen deprivation conditions and required nitrate for induction. The functional and expression properties, described in the present study, delineate TbNrt2 as a versatile transporter that may be especially suited to cope with the fluctuating (and often low) mineral nitrogen concentrations found in most natural, especially forest, soils. PMID:16201972

Heterologous production of cellobiose dehydrogenases from the basidiomycete Coprinopsis cinerea and the ascomycete Podospora anserina and their effect on saccharification of wheat straw.

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Turbe-Doan, Annick; Arfi, Yonathan; Record, Eric; Estrada-Alvarado, Isabel; Levasseur, Anthony

2013-06-01

Cellobiose dehydrogenases (CDHs) are extracellular glycosylated haemoflavoenzymes produced by many different wood-degrading and phytopathogenic fungi. Putative cellobiose dehydrogenase genes are recurrently discovered by genome sequencing projects in various phylogenetically distinct fungi. The genomes from the basidiomycete Coprinopsis cinerea and the ascomycete Podospora anserina were screened for candidate cdh genes, and one and three putative gene models were evidenced, respectively. Two putative cdh genes were selected and successfully expressed for the first time in Aspergillus niger. CDH activity was measured for both constructions (CDHcc and CDHpa), and both recombinant CDHs were purified to homogeneity and subsequently characterised. Kinetic constants were determined for several carbohydrates including β-1,4-linked di- and oligosaccharides. Optimal temperature and pH were 60 °C and 5 for CDHcc and 65-70 °C and 6 for CDHpa. Both CDHs showed a broad range of pH stability between 4 and 8. The effect of both CDHs on saccharification of micronized wheat straw by an industrial Trichoderma reesei secretome was determined. The addition of each CDH systematically decreased the release of total reducing sugars, but to different extents and according to the CDH concentration. Analytical methods were carried out to quantify the release of glucose, xylose and gluconic acid. An increase of glucose and xylose was measured at a low CDHcc concentration. At moderated and high CDHcc and CDHpa concentrations, glucose was severely reduced with a concomitant increase of gluconic acid. In conclusion, these results give new insights into the physical and chemical parameters and diversity of basidiomycetous and ascomycetous CDHs. These findings also demonstrated that CDH drastically influenced the saccharification on a natural substrate, and thus, CDH origin, concentration and potential enzymatic partners should be carefully considered in future artificial secretomes for

Regulation of melanin biosynthesis via the dihydroxynaphthalene pathway is dependent on sexual development in the ascomycete Sordaria macrospora.

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Engh, Ines; Nowrousian, Minou; Kück, Ulrich

2007-10-01

The filamentous ascomycete Sordaria macrospora accumulates melanin during sexual development. The four melanin biosynthesis genes pks, teh, sdh and tih were isolated and their homology to genes involved in 1,8 dihydroxynaphthalene (DHN) melanin biosynthesis was shown. The presence of DHN melanin in S. macrospora was further confirmed by disrupting the pks gene encoding a putative polyketide synthase and by RNA interference-mediated silencing of the sdh gene encoding a putative scytalone dehydratase. Because melanin occurs in fruiting bodies that develop through several intermediate stages within 7 days of growth, a Northern analysis of a developmental time-course was conducted. These data revealed a time-dependent regulation of teh and sdh transcript levels. Comparing the transcriptional expression by real-time PCR of melanin biosynthesis genes in the wild type under conditions allowing or repressing sexual development, a significant downregulation during vegetative growth was detected. Quantitative real-time PCR and Northern blot analysis of melanin biosynthesis gene expression in different developmental mutants confirmed that melanin biosynthesis is linked to fruiting body development and is under the control of specific regulatory genes that participate in sexual differentiation.

Susceptibility pays off: insights into the mlo-based powdery mildew resistance

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Appiano, Michela

2016-01-01

Powdery mildew (PM) is a worldwide-occurring plant disease caused by ascomycete fungi of the order Erysiphales. A conspicuous number of plant species are susceptible to this disease, the occurrence of which is increasing due to the influence of climate change. Symptoms are easy to recognize by

SPECTROSCOPIC ANALYSIS OF FIVE PHYLOGENETICALLY DISTANT FUNGI (DIVISION: ASCOMYCETE FROM VELLAR ESTUARY, SOUTHEAST COAST OF INDIA – A PILOT STUDY

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Jayachandran Subburaj

2013-04-01

Full Text Available Fungal taxonomy is dynamically driven towards controversial discipline that consequently requires changes in nomenclature. Scarcity of microbiological expertise particularly for marine fungi is another major setback for these taxonomical differences. Here, five different species pharmacologically important marine fungi under Division Ascomycete were studied for their spectral variation. This work verified the practical applicability of FT-IR microspectroscopy technique for early and rapid identification of these species based on the spectral data showed striking difference with their major biomolecules such as lipids, proteins and nucleic acids produced by them. Spectra of all the species showed striking differences while individual peaks of each spectrum are parallel to each other in their respective spectral regions. Aspergillus oryzae have intense peaks in the lipid and nucleic acid spectral region and moderate bands in the amide spectrum. Phoma herbarum and Trichoderma piluliferum showed intense peaks in the protein spectral region but moderate peaks in the lipid and nucleic acid regions. Hypocrea lixii and Meyerozyma guilliermandii have less intense peaks in all the five spectral regions. This unique spectral representation is concordant with the cluster analysis dendrogram by minimum variance statistical method where low spectroscopic distance was found between H. lixii and M. guilliermondii whereas a higher spectroscopic distance was found between P. herbarum and T. piluliferum. FTIR spectroscopy delivers a combined advantage for efficient fungal classification as well as simultaneous visualization of chemical composition of samples as evident from this study.

Role of the alpha-glucanase Agn2p in ascus-wall endolysis following sporulation in fission yeast

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Dekker, Nick; van Rijssel, Jos; Distel, Ben; Hochstenbach, Frans

2007-01-01

During sporulation in the ascomyceteous fungus Schizosaccharomyces pombe, diploid cells undergo differentiation into asci containing four haploid ascospores, which are highly resistant to environmental stresses. Although the morphogenetic processes involved in ascospore formation have been studied

Adenylyl cyclase plays a regulatory role in development, stress resistance and secondary metabolism in Fusarium fujikuroi.

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Jorge García-Martínez

Full Text Available The ascomycete fungus Fusarium fujikuroi (Gibberella fujikuroi MP-C produces secondary metabolites of biotechnological interest, such as gibberellins, bikaverin, and carotenoids. Production of these metabolites is regulated by nitrogen availability and, in a specific manner, by other environmental signals, such as light in the case of the carotenoid pathway. A complex regulatory network controlling these processes is recently emerging from the alterations of metabolite production found through the mutation of different regulatory genes. Here we show the effect of the targeted mutation of the acyA gene of F. fujikuroi, coding for adenylyl cyclase. Mutants lacking the catalytic domain of the AcyA protein showed different phenotypic alterations, including reduced growth, enhanced production of unidentified red pigments, reduced production of gibberellins and partially derepressed carotenoid biosynthesis in the dark. The phenotype differs in some aspects from that of similar mutants of the close relatives F. proliferatum and F. verticillioides: contrary to what was observed in these species, ΔacyA mutants of F. fujikuroi showed enhanced sensitivity to oxidative stress (H(2O(2, but no change in heavy metal resistance or in the ability to colonize tomato tissue, indicating a high versatility in the regulatory roles played by cAMP in this fungal group.

Mn(II) oxidation by an ascomycete fungus is linked to superoxide production during asexual reproduction.

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Hansel, Colleen M; Zeiner, Carolyn A; Santelli, Cara M; Webb, Samuel M

2012-07-31

Manganese (Mn) oxides are among the most reactive minerals within the environment, where they control the bioavailability of carbon, nutrients, and numerous metals. Although the ability of microorganisms to oxidize Mn(II) to Mn(III/IV) oxides is scattered throughout the bacterial and fungal domains of life, the mechanism and physiological basis for Mn(II) oxidation remains an enigma. Here, we use a combination of compound-specific chemical assays, microspectroscopy, and electron microscopy to show that a common Ascomycete filamentous fungus, Stilbella aciculosa, oxidizes Mn(II) to Mn oxides by producing extracellular superoxide during cell differentiation. The reactive Mn oxide phase birnessite and the reactive oxygen species superoxide and hydrogen peroxide are colocalized at the base of asexual reproductive structures. Mn oxide formation is not observed in the presence of superoxide scavengers (e.g., Cu) and inhibitors of NADPH oxidases (e.g., diphenylene iodonium chloride), enzymes responsible for superoxide production and cell differentiation in fungi. Considering the recent identification of Mn(II) oxidation by NADH oxidase-based superoxide production by a common marine bacterium (Roseobacter sp.), these results introduce a surprising homology between some prokaryotic and eukaryotic organisms in the mechanisms responsible for Mn(II) oxidation, where oxidation appears to be a side reaction of extracellular superoxide production. Given the versatility of superoxide as a redox reactant and the widespread ability of fungi to produce superoxide, this microbial extracellular superoxide production may play a central role in the cycling and bioavailability of metals (e.g., Hg, Fe, Mn) and carbon in natural systems.

Pheromones and pheromone receptors are required for proper sexual development in the homothallic ascomycete Sordaria macrospora.

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Mayrhofer, Severine; Weber, Jan M; Pöggeler, Stefanie

2006-03-01

The homothallic, filamentous ascomycete Sordaria macrospora is self-fertile and produces sexual fruiting bodies (perithecia) without a mating partner. Even so, S. macrospora transcriptionally expresses two pheromone-precursor genes (ppg1 and ppg2) and two pheromone-receptor genes (pre1 and pre2). The proteins encoded by these genes are similar to alpha-factor-like and a-factor-like pheromones and to G-protein-coupled pheromone receptors of the yeast Saccharomyces cerevisiae. It has been suggested that in S. macrospora, PPG1/PRE2 and PPG2/PRE1 form two cognate pheromone-receptor pairs. To investigate their function, we deleted (delta) pheromone-precursor genes (delta ppg1, delta ppg2) and receptor genes (delta pre1, delta pre2) and generated single- as well as double-knockout strains. No effect on vegetative growth, fruiting-body, and ascospore development was seen in the single pheromone-mutant and receptor-mutant strains, respectively. However, double-knockout strains lacking any compatible pheromone-receptor pair (delta pre2/delta ppg2, delta pre1/delta ppg1) and the double-pheromone mutant (delta ppg1/delta ppg2) displayed a drastically reduced number of perithecia and sexual spores, whereas deletion of both receptor genes (delta pre1/delta pre2) completely eliminated fruiting-body and ascospore formation. The results suggest that pheromones and pheromone receptors are required for optimal sexual reproduction of the homothallic S. macrospora.

The mating-type chromosome in the filamentous ascomycete Neurospora tetrasperma represents a model for early evolution of sex chromosomes.

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Audrius Menkis

2008-03-01

Full Text Available We combined gene divergence data, classical genetics, and phylogenetics to study the evolution of the mating-type chromosome in the filamentous ascomycete Neurospora tetrasperma. In this species, a large non-recombining region of the mating-type chromosome is associated with a unique fungal life cycle where self-fertility is enforced by maintenance of a constant state of heterokaryosis. Sequence divergence between alleles of 35 genes from the two single mating-type component strains (i.e. the homokaryotic mat A or mat a-strains, derived from one N. tetrasperma heterokaryon (mat A+mat a, was analyzed. By this approach we were able to identify the boundaries and size of the non-recombining region, and reveal insight into the history of recombination cessation. The non-recombining region covers almost 7 Mbp, over 75% of the chromosome, and we hypothesize that the evolution of the mating-type chromosome in this lineage involved two successive events. The first event was contemporaneous with the split of N. tetrasperma from a common ancestor with its outcrossing relative N. crassa and suppressed recombination over at least 6.6 Mbp, and the second was confined to a smaller region in which recombination ceased more recently. In spite of the early origin of the first "evolutionary stratum", genealogies of five genes from strains belonging to an additional N. tetrasperma lineage indicate independent initiations of suppressed recombination in different phylogenetic lineages. This study highlights the shared features between the sex chromosomes found in the animal and plant kingdoms and the fungal mating-type chromosome, despite fungi having no separate sexes. As is often found in sex chromosomes of plants and animals, recombination suppression of the mating-type chromosome of N. tetrasperma involved more than one evolutionary event, covers the majority of the mating-type chromosome and is flanked by distal regions with obligate crossovers.

Transformation of Sordaria macrospora to hygromycin B resistance: characterization of transformants by electrophoretic karyotyping and tetrad analysis.

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Walz, M; Kück, U

1995-12-01

The ascomycete Sordaria macrospora was transformed using different plasmid molecules containing the bacterial hygromycin B resistance gene (hph) under the control of different expression signals. The highest transformation frequency was obtained with vector pMW1. On this plasmid molecule, expression of the hph gene is directed by the upstream region of the isopenicillin N synthetase gene (pcbC) from the deuteromycete Acremonium chrysogenum. Southern analysis suggests that the vector copies are integrated as tandem repeats into the S. macrospora chromosomes and that duplicated sequences are most probably not inactivated by methylation during meiosis. Furthermore, the hygromycin B resistance (hygR) is not correlated with the number of integrated vector molecules. Electrophoretic karyotyping was used to further characterize S. macrospora transformants. Five chromosomal bands were separated by pulsed-field gel electrophoresis (PFGE) representing seven chromosomes with a total genome size of 39.5Mb. Hybridization analysis revealed ectopic integration of vector DNA into different chromosomes. In a few transformants, major rearrangements were detected. Transformants were sexually propagated to analyze the fate of the heterologous vector DNA. Although the hygR phenotype is stably maintained during mitosis, about a third of all lines tested showed loss of the resistance marker gene after meiosis. However, as was concluded from electrophoretic karyotyping, the resistant spores showed a Mendelian segregation of the integrated vector molecules in at least three consecutive generations. Our data indicate that heterologous marker genes can be used for transformation tagging, or the molecular mapping of chromosomal loci in S. macrospora.

Crystal structures of two tetrameric β-carbonic anhydrases from the filamentous ascomycete Sordaria macrospora.

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Lehneck, Ronny; Neumann, Piotr; Vullo, Daniela; Elleuche, Skander; Supuran, Claudiu T; Ficner, Ralf; Pöggeler, Stefanie

2014-04-01

Carbonic anhydrases (CAs) are metalloenzymes catalyzing the reversible hydration of carbon dioxide to bicarbonate (hydrogen carbonate) and protons. CAs have been identified in archaea, bacteria and eukaryotes and can be classified into five groups (α, β, γ, δ, ζ) that are unrelated in sequence and structure. The fungal β-class has only recently attracted attention. In the present study, we investigated the structure and function of the plant-like β-CA proteins CAS1 and CAS2 from the filamentous ascomycete Sordaria macrospora. We demonstrated that both proteins can substitute for the Saccharomyces cerevisiae β-CA Nce103 and exhibit an in vitro CO2 hydration activity (kcat /Km of CAS1: 1.30 × 10(6) m(-1) ·s(-1) ; CAS2: 1.21 × 10(6 ) m(-1) ·s(-1) ). To further investigate the structural properties of CAS1 and CAS2, we determined their crystal structures to a resolution of 2.7 Å and 1.8 Å, respectively. The oligomeric state of both proteins is tetrameric. With the exception of the active site composition, no further major differences have been found. In both enzymes, the Zn(2) (+) -ion is tetrahedrally coordinated; in CAS1 by Cys45, His101 and Cys104 and a water molecule and in CAS2 by the side chains of four residues (Cys56, His112, Cys115 and Asp58). Both CAs are only weakly inhibited by anions, making them good candidates for industrial applications. CAS1 and CAS2 bind by x-ray crystallography (View interaction) Structural data have been deposited in the Protein Data Bank database under accession numbers 4O1J for CAS1 and 4O1K for CAS2. © 2014 FEBS.

Genome sequencing of four Aureobasidium pullulans varieties: biotechnological potential, stress tolerance, and description of new species

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Gostinčar, Cene; Ohm, Robin A; Kogej, Tina; Sonjak, Silva; Turk, Martina; Zajc, Janja; Zalar, Polona; Grube, Martin; Sun, Hui; Han, James; Sharma, Aditi; Chiniquy, Jennifer; Ngan, Chew Yee; Lipzen, Anna; Barry, Kerrie

2014-01-01

Background Aureobasidium pullulans is a black-yeast-like fungus used for production of the polysaccharide pullulan and the antimycotic aureobasidin A, and as a biocontrol agent in agriculture. It can cause opportunistic human infections, and it inhabits various extreme environments. To promote the understanding of these traits, we performed de-novo genome sequencing of the four varieties of A. pullulans. Results The 25.43-29.62 Mb genomes of these four varieties of A. pullulans encode between...

The phocein homologue SmMOB3 is essential for vegetative cell fusion and sexual development in the filamentous ascomycete Sordaria macrospora.

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Bernhards, Yasmine; Pöggeler, Stefanie

2011-04-01

Members of the striatin family and their highly conserved interacting protein phocein/Mob3 are key components in the regulation of cell differentiation in multicellular eukaryotes. The striatin homologue PRO11 of the filamentous ascomycete Sordaria macrospora has a crucial role in fruiting body development. Here, we functionally characterized the phocein/Mob3 orthologue SmMOB3 of S. macrospora. We isolated the gene and showed that both, pro11 and Smmob3 are expressed during early and late developmental stages. Deletion of Smmob3 resulted in a sexually sterile strain, similar to the previously characterized pro11 mutant. Fusion assays revealed that ∆Smmob3 was unable to undergo self-fusion and fusion with the pro11 strain. The essential function of the SmMOB3 N-terminus containing the conserved mob domain was demonstrated by complementation analysis of the sterile S. macrospora ∆Smmob3 strain. Downregulation of either pro11 in ∆Smmob3, or Smmob3 in pro11 mutants by means of RNA interference (RNAi) resulted in synthetic sexual defects, demonstrating for the first time the importance of a putative PRO11/SmMOB3 complex in fruiting body development.

A resistência olha a resistência

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Jorge Ponciano Ribeiro

Full Text Available Resistência é um processo humano que acontece quando a pessoa se encontra sob algum tipo de ameaça. Não é essencialmente um acontecimento psicoterapêutico. Ocorre na terapia não como uma oposição a si mesmo ou ao terapeuta, mas como uma forma de se ajustar a uma nova situação. A resistência, é por natureza, a atualização do instinto de auto-preservação. E o organismo inteligentemente segue a lei da preferência. Resistência é uma forma de contato que não pode ser destruída, mas administrada, porque ela surge como uma defesa da totalidade vivenciada pela pessoa. A Resistência é, às vezes, resistência e awareness mais que ao contato. Ela revela mais o caminho seguido do que oculta a caminhada feita. A resistência é um processo natural, porque o corpo que não resiste, morre, mas falamos em processos de auto-regulação organísmica. Valorizamos mais o que mantêm a resistência funcionando do que à própria resistência. O terapeuta também resiste, ou seja, ele se auto-regula na sua relação com o cliente. Não questionamos a resistência, mas o processo que a mantêm. Trabalhamos com nove mecanismos de defesa, também tradicionalmente, chamados de resistência.

Metabolites from nematophagous fungi and nematicidal natural products from fungi as an alternative for biological control. Part I: metabolites from nematophagous ascomycetes.

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Degenkolb, Thomas; Vilcinskas, Andreas

2016-05-01

Plant-parasitic nematodes are estimated to cause global annual losses of more than US$ 100 billion. The number of registered nematicides has declined substantially over the last 25 years due to concerns about their non-specific mechanisms of action and hence their potential toxicity and likelihood to cause environmental damage. Environmentally beneficial and inexpensive alternatives to chemicals, which do not affect vertebrates, crops, and other non-target organisms, are therefore urgently required. Nematophagous fungi are natural antagonists of nematode parasites, and these offer an ecophysiological source of novel biocontrol strategies. In this first section of a two-part review article, we discuss 83 nematicidal and non-nematicidal primary and secondary metabolites found in nematophagous ascomycetes. Some of these substances exhibit nematicidal activities, namely oligosporon, 4',5'-dihydrooligosporon, talathermophilins A and B, phomalactone, aurovertins D and F, paeciloxazine, a pyridine carboxylic acid derivative, and leucinostatins. Blumenol A acts as a nematode attractant. Other substances, such as arthrosporols and paganins, play a decisive role in the life cycle of the producers, regulating the formation of reproductive or trapping organs. We conclude by considering the potential applications of these beneficial organisms in plant protection strategies.

The cross-pathway control system regulates production of the secondary metabolite toxin, sirodesmin PL, in the ascomycete, Leptosphaeria maculans

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Fox Ellen M

2011-07-01

Full Text Available Abstract Background Sirodesmin PL is a secondary metabolite toxin made by the ascomycetous plant pathogen, Leptosphaeria maculans. The sirodesmin biosynthetic genes are clustered in the genome. The key genes are a non-ribosomal peptide synthetase, sirP, and a pathway-specific transcription factor, sirZ. Little is known about regulation of sirodesmin production. Results Genes involved in regulation of sirodesmin PL in L. maculans have been identified. Two hundred random insertional T-DNA mutants were screened with an antibacterial assay for ones producing low levels of sirodesmin PL. Three such mutants were isolated and each transcribed sirZ at very low levels. One of the affected genes had high sequence similarity to Aspergillus fumigatus cpcA, which regulates the cross-pathway control system in response to amino acid availability. This gene was silenced in L. maculans and the resultant mutant characterised. When amino acid starvation was artificially-induced by addition of 3-aminotriazole for 5 h, transcript levels of sirP and sirZ did not change in the wild type. In contrast, levels of sirP and sirZ transcripts increased in the silenced cpcA mutant. After prolonged amino acid starvation the silenced cpcA mutant produced much higher amounts of sirodesmin PL than the wild type. Conclusions Production of sirodesmin PL in L. maculans is regulated by the cross pathway control gene, cpcA, either directly or indirectly via the pathway-specific transcription factor, sirZ.

Sulfonamide inhibition studies of two β-carbonic anhydrases from the ascomycete fungus Sordaria macrospora, CAS1 and CAS2.

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Vullo, Daniela; Lehneck, Ronny; Pöggeler, Stefanie; Supuran, Claudiu T

2018-12-01

The two β-carbonic anhydrases (CAs, EC 4.2.1.1) recently cloned and purified from the ascomycete fungus Sordaria macrospora, CAS1 and CAS2, were investigated for their inhibition with a panel of 39 aromatic, heterocyclic, and aliphatic sulfonamides and one sulfamate, many of which are clinically used agents. CAS1 was efficiently inhibited by tosylamide, 3-fluorosulfanilamide, and 3-chlorosulfanilamide (K I s in the range of 43.2-79.6 nM), whereas acetazolamide, methazolamide, topiramate, ethoxzolamide, dorzolamide, and brinzolamide were medium potency inhibitors (K I s in the range of 360-445 nM). CAS2 was less sensitive to sulfonamide inhibitors. The best CAS2 inhibitors were 5-amino-1,3,4-thiadiazole-2-sulfonamide (the deacetylated acetazolamide precursor) and 4-hydroxymethyl-benzenesulfonamide, with K I s in the range of 48.1-92.5 nM. Acetazolamide, dorzolamide, ethoxzolamide, topiramate, sulpiride, indisulam, celecoxib, and sulthiame were medium potency CAS2 inhibitors (K I s of 143-857 nM). Many other sulfonamides showed affinities in the high micromolar range or were ineffective as CAS1/2 inhibitors. Small changes in the structure of the inhibitor led to important differences of the activity. As these enzymes may show applications for the removal of anthropically generated polluting gases, finding modulators of their activity may be crucial for designing environmental-friendly CO 2 capture processes.

Aspects of sexual reproduction in Mycosphaerella species on wheat and barley : genetic studies on specificity, mapping, and fungicide resistance

NARCIS (Netherlands)

Ware, S.B.

2006-01-01

Mycosphaerella species are haploid ascomycetes that cause major economic losses in crops that include cereals, citrus fruits, and bananas, among others. Two organisms in this genus are Mycosphaerella graminicola (Fuckel) .I. Schröt (anamorph Sepioria tritici) and Septoriapasserinii. M graminicola is

Rapid identification of ascomycetous yeasts from clinical specimens by a molecular method based on flow cytometry and comparison with identifications from phenotypic assays.

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Page, Brent T; Shields, Christine E; Merz, William G; Kurtzman, Cletus P

2006-09-01

This study was designed to compare the identification of ascomycetous yeasts recovered from clinical specimens by using phenotypic assays (PA) and a molecular flow cytometric (FC) method. Large-subunit rRNA domains 1 and 2 (D1/D2) gene sequence analysis was also performed and served as the reference for correct strain identification. A panel of 88 clinical isolates was tested that included representatives of nine commonly encountered species and six infrequently encountered species. The PA included germ tube production, fermentation of seven carbohydrates, morphology on corn meal agar, urease and phenoloxidase activities, and carbohydrate assimilation tests when needed. The FC method (Luminex) employed species-specific oligonucleotides attached to polystyrene beads, which were hybridized with D1/D2 amplicons from the unidentified isolates. The PA identified 81 of 88 strains correctly but misidentified 4 of Candida dubliniensis, 1 of C. bovina, 1 of C. palmioleophila, and 1 of C. bracarensis. The FC method correctly identified 79 of 88 strains and did not misidentify any isolate but did not identify nine isolates because oligonucleotide probes were not available in the current library. The FC assay takes approximately 5 h, whereas the PA takes from 2 h to 5 days for identification. In conclusion, PA did well with the commonly encountered species, was not accurate for uncommon species, and takes significantly longer than the FC method. These data strongly support the potential of FC technology for rapid and accurate identification of medically important yeasts. With the introduction of new antifungals, rapid, accurate identification of pathogenic yeasts is more important than ever for guiding antifungal chemotherapy.

Systemic Resistance to Powdery Mildew in Brassica napus (AACC) and Raphanus alboglabra (RRCC) by Trichoderma harzianum TH12.

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Alkooranee, Jawadayn Talib; Yin, Yongtai; Aledan, Tamarah Raad; Jiang, Yingfen; Lu, Guangyuan; Wu, Jiangsheng; Li, Maoteng

2015-01-01

Trichoderma harzianum TH12 is a microbial pesticide for certain rapeseed diseases. The mechanism of systemic resistance induced by TH12 or its cell-free culture filtrate (CF) in Brassica napus (AACC) and Raphanus alboglabra (RRCC) to powdery mildew disease caused by ascomycete Erysiphe cruciferarum was investigated. In this study, we conducted the first large-scale global study on the cellular and molecular aspects of B. napus and R. alboglabra infected with E. cruciferarum. The histological study showed the resistance of R. alboglabra to powdery mildew disease. The growth of fungal colonies was not observed on R. alboglabra leaves at 1, 2, 4, 6, 8, and 10 days post-inoculation (dpi), whereas this was clearly observed on B. napus leaves after 6 dpi. In addition, the gene expression of six plant defense-related genes, namely, PR-1, PR-2 (a marker for SA signaling), PR-3, PDF 1.2 (a marker for JA/ET signaling), CHI620, and CHI570, for both genotypes were analyzed in the leaves of B. napus and R. alboglabra after treatment with TH12 or CF and compared with the non-treated ones. The qRT-PCR results showed that the PR-1 and PR-2 expression levels increased in E. cruciferarum-infected leaves, but decreased in the TH12-treated leaves compared with leaves treated with CF. The expression levels of PR-3 and PDF1.2 decreased in plants infected by E. cruciferarum. However, expression levels increased when the leaves were treated with TH12. For the first time, we disclosed the nature of gene expression in B. napus and R. alboglabra to explore the resistance pathways in the leaves of both genotypes infected and non-infected by powdery mildew and inoculated or non-inoculated with elicitor factors. Results suggested that R. alboglabra exhibited resistance to powdery mildew disease, and the application of T. harzianum and its CF are a useful tool to facilitate new protection methods for resist or susceptible plants.

Antifungal susceptibility profiles of 1698 yeast reference strains revealing potential emerging human pathogens.

Directory of Open Access Journals (Sweden)

Marie Desnos-Ollivier

Full Text Available New molecular identification techniques and the increased number of patients with various immune defects or underlying conditions lead to the emergence and/or the description of novel species of human and animal fungal opportunistic pathogens. Antifungal susceptibility provides important information for ecological, epidemiological and therapeutic issues. The aim of this study was to assess the potential risk of the various species based on their antifungal drug resistance, keeping in mind the methodological limitations. Antifungal susceptibility profiles to the five classes of antifungal drugs (polyens, azoles, echinocandins, allylamines and antimetabolites were determined for 1698 yeast reference strains belonging to 992 species (634 Ascomycetes and 358 Basidiomycetes. Interestingly, geometric mean minimum inhibitory concentrations (MICs of all antifungal drugs tested were significantly higher for Basidiomycetes compared to Ascomycetes (p<0.001. Twenty four strains belonging to 23 species of which 19 were Basidiomycetes seem to be intrinsically "resistant" to all drugs. Comparison of the antifungal susceptibility profiles of the 4240 clinical isolates and the 315 reference strains belonging to 53 shared species showed similar results. Even in the absence of demonstrated in vitro/in vivo correlation, knowing the in vitro susceptibility to systemic antifungal agents and the putative intrinsic resistance of yeast species present in the environment is important because they could become opportunistic pathogens.

The control of fruiting body formation in the ascomycete Sordaria macrospora Auersw. by regulation of hyphal development : An analysis based on scanning electron and light microscopic observations.

Science.gov (United States)

Hock, B; Bahn, M; Walk, R A; Nitschke, U

1978-01-01

The morphological effects of biotin and L-arginine on fruiting body formation of the ascomycete Sordaria macrospora are investigated by scanning electron and light microscopy. Biotin is recognized as an elongation factor and arginine as a branching factor in vegetative and reproductive hyphae. In the absence of exogenous biotin, development is blocked after the ascogonium-core hypha stage of protoperithecial morphogenesis, whereas linear growth of the myceliar front is maintained. The addition of exogenous arginine to a biotin deficient culture induces the formation of numerous side branches even in the older mycelium. Fruiting body formation, however, remains blocked at the protoperithecial stage as before, because of the inability of the side branches to elongate. When biotin and arginine are administered simultaneously, a most vigorous branching and growth are induced in the older mycelium, accompanied by a rapid and maximal formation of fruiting bodies. The results are summarized in a model of the exogenous control of hyphal morphogenesis. The model is designed to explain the relationship between fruiting and hyphal density as well as the edge effect on fruiting body formation.

The Genome and Development-Dependent Transcriptomes of Pyronema confluens: A Window into Fungal Evolution

Science.gov (United States)

Traeger, Stefanie; Altegoer, Florian; Freitag, Michael; Gabaldon, Toni; Kempken, Frank; Kumar, Abhishek; Marcet-Houben, Marina; Pöggeler, Stefanie; Stajich, Jason E.; Nowrousian, Minou

2013-01-01

Fungi are a large group of eukaryotes found in nearly all ecosystems. More than 250 fungal genomes have already been sequenced, greatly improving our understanding of fungal evolution, physiology, and development. However, for the Pezizomycetes, an early-diverging lineage of filamentous ascomycetes, there is so far only one genome available, namely that of the black truffle, Tuber melanosporum, a mycorrhizal species with unusual subterranean fruiting bodies. To help close the sequence gap among basal filamentous ascomycetes, and to allow conclusions about the evolution of fungal development, we sequenced the genome and assayed transcriptomes during development of Pyronema confluens, a saprobic Pezizomycete with a typical apothecium as fruiting body. With a size of 50 Mb and ∼13,400 protein-coding genes, the genome is more characteristic of higher filamentous ascomycetes than the large, repeat-rich truffle genome; however, some typical features are different in the P. confluens lineage, e.g. the genomic environment of the mating type genes that is conserved in higher filamentous ascomycetes, but only partly conserved in P. confluens. On the other hand, P. confluens has a full complement of fungal photoreceptors, and expression studies indicate that light perception might be similar to distantly related ascomycetes and, thus, represent a basic feature of filamentous ascomycetes. Analysis of spliced RNA-seq sequence reads allowed the detection of natural antisense transcripts for 281 genes. The P. confluens genome contains an unusually high number of predicted orphan genes, many of which are upregulated during sexual development, consistent with the idea of rapid evolution of sex-associated genes. Comparative transcriptomics identified the transcription factor gene pro44 that is upregulated during development in P. confluens and the Sordariomycete Sordaria macrospora. The P. confluens pro44 gene (PCON_06721) was used to complement the S. macrospora pro44 deletion

The genome and development-dependent transcriptomes of Pyronema confluens: a window into fungal evolution.

Directory of Open Access Journals (Sweden)

Stefanie Traeger

Full Text Available Fungi are a large group of eukaryotes found in nearly all ecosystems. More than 250 fungal genomes have already been sequenced, greatly improving our understanding of fungal evolution, physiology, and development. However, for the Pezizomycetes, an early-diverging lineage of filamentous ascomycetes, there is so far only one genome available, namely that of the black truffle, Tuber melanosporum, a mycorrhizal species with unusual subterranean fruiting bodies. To help close the sequence gap among basal filamentous ascomycetes, and to allow conclusions about the evolution of fungal development, we sequenced the genome and assayed transcriptomes during development of Pyronema confluens, a saprobic Pezizomycete with a typical apothecium as fruiting body. With a size of 50 Mb and ~13,400 protein-coding genes, the genome is more characteristic of higher filamentous ascomycetes than the large, repeat-rich truffle genome; however, some typical features are different in the P. confluens lineage, e.g. the genomic environment of the mating type genes that is conserved in higher filamentous ascomycetes, but only partly conserved in P. confluens. On the other hand, P. confluens has a full complement of fungal photoreceptors, and expression studies indicate that light perception might be similar to distantly related ascomycetes and, thus, represent a basic feature of filamentous ascomycetes. Analysis of spliced RNA-seq sequence reads allowed the detection of natural antisense transcripts for 281 genes. The P. confluens genome contains an unusually high number of predicted orphan genes, many of which are upregulated during sexual development, consistent with the idea of rapid evolution of sex-associated genes. Comparative transcriptomics identified the transcription factor gene pro44 that is upregulated during development in P. confluens and the Sordariomycete Sordaria macrospora. The P. confluens pro44 gene (PCON_06721 was used to complement the S. macrospora

Description of Taphrina antarctica f.a. sp. nov., a new anamorphic ascomycetous yeast species associated with Antarctic endolithic microbial communities and transfer of four Lalaria species in the genus Taphrina.

Science.gov (United States)

Selbmann, Laura; Turchetti, Benedetta; Yurkov, Andrey; Cecchini, Clarissa; Zucconi, Laura; Isola, Daniela; Buzzini, Pietro; Onofri, Silvano

2014-07-01

In the framework of a large-scale rock sampling in Continental Antarctica, a number of yeasts have been isolated. Two strains that are unable to grow above 20 °C and that have low ITS sequence similarities with available data in the public domain were found. The D1/D2 LSU molecular phylogeny placed them in an isolated position in the genus Taphrina, supporting their affiliation to a not yet described species. Because the new species is able to grow in its anamorphic state only, the species Taphrina antarctica f.a. (forma asexualis) sp. nov. has been proposed to accommodate both strains (type strain DBVPG 5268(T), DSM 27485(T) and CBS 13532(T)). Lalaria and Taphrina species are dimorphic ascomycetes, where the anamorphic yeast represents the saprotrophic state and the teleomorph is the parasitic counterpart on plants. This is the first record for this genus in Antarctica; since plants are absent on the continent, we hypothesize that the fungus may have focused on the saprotrophic part of its life cycle to overcome the absence of its natural host and adapt environmental constrains. Following the new International Code of Nomenclature for Algae, Fungi and Plants (Melbourne Code 2011) the reorganization of Taphrina-Lalaria species in the teleomorphic genus Taphrina is proposed. We emend the diagnosis of the genus Taphrina to accommodate asexual saprobic states of these fungi. Taphrina antarctica was registered in MycoBank under MB 808028.

Genome sequencing of four Aureobasidium pullulans varieties: biotechnological potential, stress tolerance, and description of new species.

Science.gov (United States)

Gostinčar, Cene; Ohm, Robin A; Kogej, Tina; Sonjak, Silva; Turk, Martina; Zajc, Janja; Zalar, Polona; Grube, Martin; Sun, Hui; Han, James; Sharma, Aditi; Chiniquy, Jennifer; Ngan, Chew Yee; Lipzen, Anna; Barry, Kerrie; Grigoriev, Igor V; Gunde-Cimerman, Nina

2014-07-01

Aureobasidium pullulans is a black-yeast-like fungus used for production of the polysaccharide pullulan and the antimycotic aureobasidin A, and as a biocontrol agent in agriculture. It can cause opportunistic human infections, and it inhabits various extreme environments. To promote the understanding of these traits, we performed de-novo genome sequencing of the four varieties of A. pullulans. The 25.43-29.62 Mb genomes of these four varieties of A. pullulans encode between 10266 and 11866 predicted proteins. Their genomes encode most of the enzyme families involved in degradation of plant material and many sugar transporters, and they have genes possibly associated with degradation of plastic and aromatic compounds. Proteins believed to be involved in the synthesis of pullulan and siderophores, but not of aureobasidin A, are predicted. Putative stress-tolerance genes include several aquaporins and aquaglyceroporins, large numbers of alkali-metal cation transporters, genes for the synthesis of compatible solutes and melanin, all of the components of the high-osmolarity glycerol pathway, and bacteriorhodopsin-like proteins. All of these genomes contain a homothallic mating-type locus. The differences between these four varieties of A. pullulans are large enough to justify their redefinition as separate species: A. pullulans, A. melanogenum, A. subglaciale and A. namibiae. The redundancy observed in several gene families can be linked to the nutritional versatility of these species and their particular stress tolerance. The availability of the genome sequences of the four Aureobasidium species should improve their biotechnological exploitation and promote our understanding of their stress-tolerance mechanisms, diverse lifestyles, and pathogenic potential.

Lipidomics of Candida albicans biofilms reveals phase-dependent production of phospholipid molecular classes and role for lipid rafts in biofilm formation.

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Lattif, Ali Abdul; Mukherjee, Pranab K; Chandra, Jyotsna; Roth, Mary R; Welti, Ruth; Rouabhia, Mahmoud; Ghannoum, Mahmoud A

2011-11-01

Candida albicans-associated bloodstream infections are linked to the ability of this yeast to form biofilms. In this study, we used lipidomics to compare the lipid profiles of C. albicans biofilms and planktonic cells, in early and mature developmental phases. Our results showed that significant differences exist in lipid composition in both developmental phases. Biofilms contained higher levels of phospholipid and sphingolipids than planktonic cells (nmol per g biomass, Pbiofilms compared to planktonic cells (P≤0.05). The ratio of phosphatidylcholine to phosphatidylethanolamine was lower in biofilms compared to planktonic cells in both early (1.17 vs 2.52, P≤0.001) and late (2.34 vs 3.81, P≤0.001) developmental phases. The unsaturation index of phospholipids decreased with time, with this effect being particularly strong for biofilms. Inhibition of the biosynthetic pathway for sphingolipid [mannosyl diinositolphosphoryl ceramide, M(IP)₂C] by myriocin or aureobasidin A, and disruption of the gene encoding inositolphosphotransferase (Ipt1p), abrogated the ability of C. albicans to form biofilms. The differences in lipid profiles between biofilms and planktonic Candida cells may have important implications for the biology and antifungal resistance of biofilms.

Identification and manipulation of the pleuromutilin gene cluster from Clitopilus passeckerianus for increased rapid antibiotic production

Science.gov (United States)

Bailey, Andy M.; Alberti, Fabrizio; Kilaru, Sreedhar; Collins, Catherine M.; de Mattos-Shipley, Kate; Hartley, Amanda J.; Hayes, Patrick; Griffin, Alison; Lazarus, Colin M.; Cox, Russell J.; Willis, Christine L.; O'Dwyer, Karen; Spence, David W.; Foster, Gary D.

2016-05-01

Semi-synthetic derivatives of the tricyclic diterpene antibiotic pleuromutilin from the basidiomycete Clitopilus passeckerianus are important in combatting bacterial infections in human and veterinary medicine. These compounds belong to the only new class of antibiotics for human applications, with novel mode of action and lack of cross-resistance, representing a class with great potential. Basidiomycete fungi, being dikaryotic, are not generally amenable to strain improvement. We report identification of the seven-gene pleuromutilin gene cluster and verify that using various targeted approaches aimed at increasing antibiotic production in C. passeckerianus, no improvement in yield was achieved. The seven-gene pleuromutilin cluster was reconstructed within Aspergillus oryzae giving production of pleuromutilin in an ascomycete, with a significant increase (2106%) in production. This is the first gene cluster from a basidiomycete to be successfully expressed in an ascomycete, and paves the way for the exploitation of a metabolically rich but traditionally overlooked group of fungi.

Fusarium graminearum and its interactions with cereal heads: studies in the proteomics era

OpenAIRE

Fen eYang; Fen eYang; Susanne eJacobsen; Hans J. L. Jørgensen; David B. Collinge; Birte eSvensson; Christine eFinnie

2013-01-01

The ascomycete fungal pathogen Fusarium graminearum is the causal agent of Fusarium head blight (FHB) in wheat and barley. This disease leads to significant losses of crop yield, and especially quality through the contamination by diverse fungal mycotoxins, which constitute a significant threat to the health of humans and animals. In recent years, high-throughput proteomics, aiming at identifying a broad spectrum of proteins with a potential role in the pathogenicity and host resistance, has ...

A study on heat resistance of high temperature resistant coating

Energy Technology Data Exchange (ETDEWEB)

Zhang, Liping; Wang, Xueying; Zhang, Qibin; Qin, Yanlong; Lin, Zhu [Research Institute of Engineering Technology of CNPC, Tianjin (China)

2005-04-15

A high temperature resistant coating has been developed, which is mainly for heavy oil production pipes deserved the serious corrosion. The coating has excellent physical and mechanical performance and corrosion resistance at room and high temperature. In order to simulate the underground working condition of heavy oil pipes,the heat resistance of the high temperature resistant coating has been studied. The development and a study on the heat resistance of the DHT high temperature resistance coating have been introduced in this paper

A study on heat resistance of high temperature resistant coating

International Nuclear Information System (INIS)

Zhang, Liping; Wang, Xueying; Zhang, Qibin; Qin, Yanlong; Lin, Zhu

2005-01-01

A high temperature resistant coating has been developed, which is mainly for heavy oil production pipes deserved the serious corrosion. The coating has excellent physical and mechanical performance and corrosion resistance at room and high temperature. In order to simulate the underground working condition of heavy oil pipes,the heat resistance of the high temperature resistant coating has been studied. The development and a study on the heat resistance of the DHT high temperature resistance coating have been introduced in this paper

Dinitroaniline herbicide resistance in a multiple-resistant Lolium rigidum population.

Science.gov (United States)

Chen, Jinyi; Yu, Qin; Owen, Mechelle; Han, Heping; Powles, Stephen

2018-04-01

The pre-emergence dinitroaniline herbicides (such as trifluralin and pendimethalin) are vital to Australian no-till farming systems. A Lolium rigidum population collected from the Western Australian grain belt with a 12-year trifluralin use history was characterised for resistance to dinitroaniline, acetyl CoA carboxylase (ACCase)- and acetolactate synthase (ALS)-inhibiting herbicides. Target-site resistance mechanisms were investigated. This L. rigidum population exhibited 32-fold resistance to trifluralin, as compared with the susceptible population. It also displayed 12- to 30-fold cross-resistance to other dinitroaniline herbicides (pendimethalin, ethalfluralin and oryzalin). In addition, this population showed multiple resistance to commonly used post-emergence ACCase- and ALS-inhibiting herbicides. Two target-site α-tubulin gene mutations (Val-202-Phe and Thr-239-Ile) previously documented in other dinitroaniline-resistant weed species were identified, and some known target-site mutations in ACCase (Ile-1781-Leu, Asp-2078-Gly and Cys-2088-Arg) and ALS (Pro-197-Gln/Ser) were found in the same population. An agar-based Petri dish screening method was established for the rapid diagnosis of resistance to dinitroaniline herbicides. Evolution of target-site resistance to both pre- and post-emergence herbicides was confirmed in a single L. rigidum population. The α-tubulin mutations Val-202-Phe and Thr-239-Ile, documented here for the first time in L. rigidum, are likely to be responsible for dinitroaniline resistance in this population. Early detection of dinitroaniline herbicide resistance and integrated weed management strategies are needed to maintain the effectiveness of dinitroaniline herbicides. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Higher marine fungi from mangroves (Manglicolous fungi)

Digital Repository Service at National Institute of Oceanography (India)

ChinnaRaj, S.

of higher marine fungi which included 23 Ascomycetes, 2 Basidiomycetes and 17 Deuteromycetes (Kohlmeyer and Kohlmeyer, 1979). Hyde (1990a) listed 120 species from 29 mangroves from all over the World this includes 87 Ascomycetes, 2 Basidiomycetes and 31...

Etoxazole resistance in predatory mite Phytoseiulus persimilis A.-H. (Acari: Phytoseiidae): Cross-resistance, inheritance and biochemical resistance mechanisms.

Science.gov (United States)

Yorulmaz Salman, Sibel; Aydınlı, Fatma; Ay, Recep

2015-07-01

Phytoseiulus persimilis of the family Phytoseiidae is an effective predatory mite species that is used to control pest mites. The LC50 and LC60 values of etoxazole were determined on P. persimilis using a leaf-disc method and spraying tower. A laboratory selection population designated ETO6 was found to have a 111.63-fold resistance to etoxazole following 6 selection cycles. This population developed low cross-resistance to spinosad, spiromesifen, acetamiprid, indoxacarb, chlorantraniliprole, milbemectin and moderate cross-resistance to deltamethrin. PBO, IBP and DEM synergised resistance 3.17-, 2.85- and 3.60-fold respectively. Crossing experiments revealed that etoxazole resistance in the ETO6 population was an intermediately dominant and polygenic. In addition, detoxifying enzyme activities were increased 2.71-fold for esterase, 3.09-fold for glutathione S-transferase (GST) and 2.76-fold for cytochrome P450 monooxygenase (P450) in the ETO6 population. Selection for etoxazole under laboratory conditions resulted in the development of etoxazole resistance in the predatory mite P. persimilis that are resistant to pesticides are considered valuable for use in resistance management programmes within integrated pest control strategies. Copyright © 2014 Elsevier Inc. All rights reserved.

DIRProt: a computational approach for discriminating insecticide resistant proteins from non-resistant proteins.

Science.gov (United States)

Meher, Prabina Kumar; Sahu, Tanmaya Kumar; Banchariya, Anjali; Rao, Atmakuri Ramakrishna

2017-03-24

Insecticide resistance is a major challenge for the control program of insect pests in the fields of crop protection, human and animal health etc. Resistance to different insecticides is conferred by the proteins encoded from certain class of genes of the insects. To distinguish the insecticide resistant proteins from non-resistant proteins, no computational tool is available till date. Thus, development of such a computational tool will be helpful in predicting the insecticide resistant proteins, which can be targeted for developing appropriate insecticides. Five different sets of feature viz., amino acid composition (AAC), di-peptide composition (DPC), pseudo amino acid composition (PAAC), composition-transition-distribution (CTD) and auto-correlation function (ACF) were used to map the protein sequences into numeric feature vectors. The encoded numeric vectors were then used as input in support vector machine (SVM) for classification of insecticide resistant and non-resistant proteins. Higher accuracies were obtained under RBF kernel than that of other kernels. Further, accuracies were observed to be higher for DPC feature set as compared to others. The proposed approach achieved an overall accuracy of >90% in discriminating resistant from non-resistant proteins. Further, the two classes of resistant proteins i.e., detoxification-based and target-based were discriminated from non-resistant proteins with >95% accuracy. Besides, >95% accuracy was also observed for discrimination of proteins involved in detoxification- and target-based resistance mechanisms. The proposed approach not only outperformed Blastp, PSI-Blast and Delta-Blast algorithms, but also achieved >92% accuracy while assessed using an independent dataset of 75 insecticide resistant proteins. This paper presents the first computational approach for discriminating the insecticide resistant proteins from non-resistant proteins. Based on the proposed approach, an online prediction server DIRProt has

A double EPSPS gene mutation endowing glyphosate resistance shows a remarkably high resistance cost.

Science.gov (United States)

Han, Heping; Vila-Aiub, Martin M; Jalaludin, Adam; Yu, Qin; Powles, Stephen B

2017-12-01

A novel glyphosate resistance double point mutation (T102I/P106S, TIPS) in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene has been recently identified for the first time only in the weed species Eleusine indica. Quantification of plant resistance cost associated with the TIPS and the often reported glyphosate resistance single P106S mutation was performed. A significant resistance cost (50% in seed number currency) associated with the homozygous TIPS but not the homozygous P106S EPSPS variant was identified in E. indica plants. The resistance cost associated with the TIPS mutation escalated to 85% in plants under resource competition with rice crops. The resistance cost was not detected in nonhomozygous TIPS plants denoting the recessive nature of the cost associated with the TIPS allele. An excess of 11-fold more shikimate and sixfold more quinate in the shikimate pathway was detected in TIPS plants in the absence of glyphosate treatment compared to wild type, whereas no changes in these compounds were observed in P106S plants when compared to wild type. TIPS plants show altered metabolite levels in several other metabolic pathways that may account for the expression of the observed resistance cost. © 2017 John Wiley & Sons Ltd.

A Gene-for-Gene Relationship Between Wheat and Mycosphaerella graminicola, the Septoria Tritici Blotch Pathogen.

Science.gov (United States)

Brading, Penny A; Verstappen, Els C P; Kema, Gert H J; Brown, James K M

2002-04-01

ABSTRACT Specific resistances to isolates of the ascomycete fungus Mycosphaerella graminicola, which causes Septoria tritici blotch of wheat, have been detected in many cultivars. Cvs. Flame and Hereward, which have specific resistance to the isolate IPO323, were crossed with the susceptible cv. Longbow. The results of tests on F1 and F2 progeny indicated that a single semidominant gene controls resistance to IPO323 in each of the resistant cultivars. This was confirmed in F3 families of Flame x Longbow, which were either homozygous resistant, homozygous susceptible, or segregating in tests with IPO323 but were uniformly susceptible to another isolate, IPO94269. None of 100 F2 progeny of Flame x Hereward were susceptible to IPO323, indicating that the resistance genes in these two cultivars are the same, closely linked, or allelic. The resistance gene in cv. Flame was mapped to the short arm of chromosome 3A using microsatellite markers and was named Stb6. Fifty-nine progeny of a cross between IPO323 and IPO94269 were used in complementary genetic analysis of the pathogen to test a gene-for-gene relationship between Stb6 and the avirulence gene in IPO323. Avirulence to cvs. Flame, Hereward, Shafir, Bezostaya 1, and Vivant and the breeding line NSL92-5719 cosegregated, and the ratio of virulent to avirulent was close to 1:1, suggesting that these wheat lines may all recognize the same avirulence gene and may all have Stb6. Together, these data provide the first demonstration that isolate-specific resistance of wheat to Septoria tritici blotch follows a gene-for-gene relationship.

A fractal-like resistive network

International Nuclear Information System (INIS)

Saggese, A; De Luca, R

2014-01-01

The equivalent resistance of a fractal-like network is calculated by means of approaches similar to those employed in defining the equivalent resistance of an infinite ladder. Starting from an elementary triangular circuit, a fractal-like network, named after Saggese, is developed. The equivalent resistance of finite approximations of this network is measured, and the didactical implications of the model are highlighted. (paper)

Molecular Characterization and Functional Analysis of PR-1-Like Proteins Identified from the Wheat Head Blight Fungus Fusarium graminearum.

Science.gov (United States)

Lu, Shunwen; Edwards, Michael C

2018-04-01

The group 1 pathogenesis-related (PR-1) proteins originally identified from plants and their homologs are also found in other eukaryotic kingdoms. Studies on nonplant PR-1-like (PR-1L) proteins have been pursued widely in humans and animals but rarely in filamentous ascomycetes. Here, we report the characterization of four PR-1L proteins identified from the ascomycete fungus Fusarium graminearum, the primary cause of Fusarium head blight of wheat and barley (designated FgPR-1L). Molecular cloning revealed that the four FgPR-1L proteins are all encoded by small open reading frames (612 to 909 bp) that are often interrupted by introns, in contrast to plant PR-1 genes that lack introns. Sequence analysis indicated that all FgPR-1L proteins contain the PR-1-specific three-dimensional structure, and one of them features a C-terminal transmembrane (TM) domain that has not been reported for any stand-alone PR-1 proteins. Transcriptional analysis revealed that the four FgPR-1L genes are expressed in axenic cultures and in planta with different spatial or temporal expression patterns. Phylogenetic analysis indicated that fungal PR-1L proteins fall into three major groups, one of which harbors FgPR-1L-2-related TM-containing proteins from both phytopathogenic and human-pathogenic ascomycetes. Low-temperature sodium dodecyl sulfate polyacrylamide gel electrophoresis and proteolytic assays indicated that the recombinant FgPR-1L-4 protein exists as a monomer and is resistant to subtilisin of the serine protease family. Functional analysis confirmed that deletion of the FgPR-1L-4 gene from the fungal genome results in significantly reduced virulence on susceptible wheat. This study provides the first example that the F. graminearum-wheat interaction involves a pathogen-derived PR-1L protein that affects fungal virulence on the host.

Systematic deletion of homeobox genes in Podospora anserina uncovers their roles in shaping the fruiting body.

Directory of Open Access Journals (Sweden)

Evelyne Coppin

Full Text Available Higher fungi, which comprise ascomycetes and basidiomycetes, play major roles in the biosphere. Their evolutionary success may be due to the extended dikaryotic stage of their life cycle, which is the basis for their scientific name: the Dikarya. Dikaryosis is maintained by similar structures, the clamp in basidiomycetes and the crozier in ascomycetes. Homeodomain transcription factors are required for clamp formation in all basidiomycetes studied. We identified all the homeobox genes in the filamentous ascomycete fungus Podospora anserina and constructed deletion mutants for each of these genes and for a number of gene combinations. Croziers developed normally in these mutants, including those with up to six deleted homeogenes. However, some mutants had defects in maturation of the fruiting body, an effect that could be rescued by providing wild-type maternal hyphae. Analysis of mutants deficient in multiple homeogenes revealed interactions between the genes, suggesting that they operate as a complex network. Similar to their role in animals and plants, homeodomain transcription factors in ascomycetes are involved in shaping multicellular structures.

Systematic deletion of homeobox genes in Podospora anserina uncovers their roles in shaping the fruiting body.

Science.gov (United States)

Coppin, Evelyne; Berteaux-Lecellier, Véronique; Bidard, Frédérique; Brun, Sylvain; Ruprich-Robert, Gwenaël; Espagne, Eric; Aït-Benkhali, Jinane; Goarin, Anne; Nesseir, Audrey; Planamente, Sara; Debuchy, Robert; Silar, Philippe

2012-01-01

Higher fungi, which comprise ascomycetes and basidiomycetes, play major roles in the biosphere. Their evolutionary success may be due to the extended dikaryotic stage of their life cycle, which is the basis for their scientific name: the Dikarya. Dikaryosis is maintained by similar structures, the clamp in basidiomycetes and the crozier in ascomycetes. Homeodomain transcription factors are required for clamp formation in all basidiomycetes studied. We identified all the homeobox genes in the filamentous ascomycete fungus Podospora anserina and constructed deletion mutants for each of these genes and for a number of gene combinations. Croziers developed normally in these mutants, including those with up to six deleted homeogenes. However, some mutants had defects in maturation of the fruiting body, an effect that could be rescued by providing wild-type maternal hyphae. Analysis of mutants deficient in multiple homeogenes revealed interactions between the genes, suggesting that they operate as a complex network. Similar to their role in animals and plants, homeodomain transcription factors in ascomycetes are involved in shaping multicellular structures.

Utilização de linhagens diplóides uvsH//uvsH de Aspergillus nidulans (Ascomycetes para a avaliação do potencial recombinagênico de agentes químicos e físicos uvsH//uvsH diploid strain favors an efficient method to evaluate the recombinagenic effect of chemical and physical agents in Aspergillus nidulans (Ascomycetes

Directory of Open Access Journals (Sweden)

Francielle Baptista

2001-05-01

Full Text Available O ascomiceto Aspergillus nidulans apresenta-se como um excelente sistema para o estudo da recombinação somática, por passar grande parte de seu ciclo celular em G2 e por apresentar mutações uvs que promovem aumento das freqüências normais de recombinação mitótica (uvsF e uvsH. O presente trabalho teve como objetivo obter uma nova linhagem diplóide de A. nidulans, com características apropriadas para estudos da recombinagênese, tais como: hetererozigose para marcadores nutricionais e de coloração de conidios e homozigose para a mutação uvsH. A maior sensibilidade do diplóide uvsH//uvsH no monitoramento de eventos de recombinação mitótica foi demonstrada através dos mais altos índices de recombinação mitótica espontânea por ele apresentados, em comparação com o diplóide uvsH+//uvsH +. A nova linhagem apresenta-se como uma ferramenta versátil, podendo ser utilizada em diferentes estudos relacionados à recombinação mitótica em A. nidulansAscomycete Aspergillus nidulans is an excellent system for mitotic crossing-over studies. This is due to the fact that much of its cell cycle is passed in G2 and presents uvs mutations that increase frequencies of normal mitotic recombinations (uvsF and uvsH. The aim of this research was to obtain a new diploid strain of A. nidulans with proper characteristics for recombinagenesis investigations, or rather, heterozygous for nutritional markers and conidia coloration and homozygous for uvsH mutation. Higher sensitivity of diploid uvsH//uvsH in the monitoring of mitotic recombination events was shown by higher indexes of the diploid’s spontaneous mitotic recombination when compared with diploid uvsH+//uvsH +. New strain is a versatile tool that may be used in different studies on mitotic recombination in A. nidulans

A bacterial antibiotic-resistance gene that complements the human multidrug-resistance P-glycoprotein gene

NARCIS (Netherlands)

van Veen, HW; Callaghan, R; Soceneantu, L; Sardini, A; Konings, WN; Higgins, CF

1998-01-01

Bacteria have developed many fascinating antibiotic-resistance mechanisms(1,2). A protein in Lactococcus lactis, LmrA, mediates antibiotic resistance by extruding amphiphilic compounds from the inner leaflet of the cytoplasmic membrane(3,4). Unlike other known bacterial multidrug-resistance

Resistance to lambda-cyhalothrin in Spanish field populations of Ceratitis capitata and metabolic resistance mediated by P450 in a resistant strain.

Science.gov (United States)

Arouri, Rabeh; Le Goff, Gaelle; Hemden, Hiethem; Navarro-Llopis, Vicente; M'saad, Mariem; Castañera, Pedro; Feyereisen, René; Hernández-Crespo, Pedro; Ortego, Félix

2015-09-01

The withdrawal of malathion in the European Union in 2009 resulted in a large increase in lambda-cyhalothrin applications for the control of the Mediterranean fruit fly, Ceratitis capitata, in Spanish citrus crops. Spanish field populations of C. capitata have developed resistance to lambda-cyhalothrin (6-14-fold), achieving LC50 values (129-287 ppm) higher than the recommended concentration for field treatments (125 ppm). These results contrast with the high susceptibility to lambda-cyhalothrin found in three Tunisian field populations. We have studied the mechanism of resistance in the laboratory-selected resistant strain W-1Kλ (205-fold resistance). Bioassays with synergists showed that resistance was almost completely suppressed by the P450 inhibitor PBO. The study of the expression of 53 P450 genes belonging to the CYP4, CYP6, CYP9 and CYP12 families in C. capitata revealed that CYP6A51 was overexpressed (13-18-fold) in the resistant strain. The W-1Kλ strain also showed high levels of cross-resistance to etofenprox (240-fold) and deltamethrin (150-fold). Field-evolved resistance to lambda-cyhalothrin has been found in C. capitata. Metabolic resistance mediated by P450 appears to be the main resistance mechanism in the resistant strain W-1Kλ. The levels of cross-resistance found may compromise the effectiveness of other pyrethroids for the control of this species. © 2014 Society of Chemical Industry. © 2014 Society of Chemical Industry.

Phenylphenalenones protect banana plants from infection by Mycosphaerella fijiensis and are deactivated by metabolic conversion.

Science.gov (United States)

Hidalgo, William; Chandran, Jima N; Menezes, Riya C; Otálvaro, Felipe; Schneider, Bernd

2016-03-01

Phenylphenalenones, polycyclic aromatic natural products from some monocotyledonous plants, are known as phytoalexins in banana (Musa spp.). In this study, (1) H nuclear magnetic resonance (NMR)-based metabolomics along with liquid chromatography and mass spectrometry were used to explore the chemical responses of the susceptible 'Williams' and the resistant 'Khai Thong Ruang' Musa varieties to the ascomycete fungus Mycosphaerella fijiensis, the agent of the black leaf Sigatoka disease. Principal component analysis discriminated strongly between infected and non-infected plant tissue, mainly because of specialized metabolism induced in response to the fungus. Phenylphenalenones are among the major induced compounds, and the resistance level of the plants was correlated with the progress of the disease. However, a virulent strain of M. fijiensis was able to overcome plant resistance by converting phenylphenalenones to sulfate conjugates. Here, we report the first metabolic detoxification of fungitoxic phenylphenalenones to evade the chemical defence of Musa plants. © 2015 John Wiley & Sons Ltd.

Mapping resistance to powdery mildew in barley reveals a large-effect nonhost resistance QTL.

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Romero, Cynara C T; Vermeulen, Jasper P; Vels, Anton; Himmelbach, Axel; Mascher, Martin; Niks, Rients E

2018-05-01

Resistance factors against non-adapted powdery mildews were mapped in barley. Some QTLs seem effective only to non-adapted mildews, while others also play a role in defense against the adapted form. The durability and effectiveness of nonhost resistance suggests promising practical applications for crop breeding, relying upon elucidation of key aspects of this type of resistance. We investigated which genetic factors determine the nonhost status of barley (Hordeum vulgare L.) to powdery mildews (Blumeria graminis). We set out to verify whether genes involved in nonhost resistance have a wide effectiveness spectrum, and whether nonhost resistance genes confer resistance to the barley adapted powdery mildew. Two barley lines, SusBgt SC and SusBgt DC , with some susceptibility to the wheat powdery mildew B. graminis f.sp. tritici (Bgt) were crossed with cv Vada to generate two mapping populations. Each population was assessed for level of infection against four B. graminis ff.spp, and QTL mapping analyses were performed. Our results demonstrate polygenic inheritance for nonhost resistance, with some QTLs effective only to non-adapted mildews, while others play a role against adapted and non-adapted forms. Histology analyses of nonhost interaction show that most penetration attempts are stopped in association with papillae, and also suggest independent layers of defence at haustorium establishment and conidiophore formation. Nonhost resistance of barley to powdery mildew relies mostly on non-hypersensitive mechanisms. A large-effect nonhost resistance QTL mapped to a 1.4 cM interval is suitable for map-based cloning.

The promoter of the glucoamylase-encoding gene of Aspergillus niger functions in Ustilago maydis

Energy Technology Data Exchange (ETDEWEB)

Smith, T.L. (Dept. of Agriculture, Madison, WI (United States) Univ. of Wisconsin, Madison (United States)); Gaskell, J.; Cullen, D. (Dept. of Agriculture, Madison, WI (United States)); Berka, R.M.; Yang, M.; Henner, D.J. (Genentech Inc., San Francisco, CA (United States))

1990-01-01

Promoter sequences from the Aspergillus niger glucoamylase-encoding gene (glaA) were linked to the bacterial hygromycin (Hy) phosphotransferase-encoding gene (hph) and this chimeric marker was used to select Hy-resistant (Hy[sup R]) Ustilago maydis transformants. This is an example of an Ascomycete promoter functioning in a Basidiomycete. Hy[sup R] transformants varied with respect to copy number of integrated vector, mitotic stability, and tolerance to Hy. Only 216 bp of glaA promoter sequence is required for expression in U. maydis but this promoter is not induced by starch as it is in Aspergillus spp. The transcription start points are the same in U. maydis and A. niger.

Mapping the resistance-associated mobilome of a carbapenem-resistant Klebsiella pneumoniae strain reveals insights into factors shaping these regions and facilitates generation of a 'resistance-disarmed' model organism.

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Bi, Dexi; Jiang, Xiaofei; Sheng, Zi-Ke; Ngmenterebo, David; Tai, Cui; Wang, Minggui; Deng, Zixin; Rajakumar, Kumar; Ou, Hong-Yu

2015-10-01

This study aims to investigate the landscape of the mobile genome, with a focus on antibiotic resistance-associated factors in carbapenem-resistant Klebsiella pneumoniae. The mobile genome of the completely sequenced K. pneumoniae HS11286 strain (an ST11, carbapenem-resistant, near-pan-resistant, clinical isolate) was annotated in fine detail. The identified mobile genetic elements were mapped to the genetic contexts of resistance genes. The blaKPC-2 gene and a 26 kb region containing 12 clustered antibiotic resistance genes and one biocide resistance gene were deleted, and the MICs were determined again to ensure that antibiotic resistance had been lost. HS11286 contains six plasmids, 49 ISs, nine transposons, two separate In2-related integron remnants, two integrative and conjugative elements (ICEs) and seven prophages. Sixteen plasmid-borne resistance genes were identified, 14 of which were found to be directly associated with Tn1721-, Tn3-, Tn5393-, In2-, ISCR2- and ISCR3-derived elements. IS26 appears to have actively moulded several of these genetic regions. The deletion of blaKPC-2, followed by the deletion of a 26 kb region containing 12 clustered antibiotic resistance genes, progressively decreased the spectrum and level of resistance exhibited by the resultant mutant strains. This study has reiterated the role of plasmids as bearers of the vast majority of resistance genes in this species and has provided valuable insights into the vital role played by ISs, transposons and integrons in shaping the resistance-coding regions in this important strain. The 'resistance-disarmed' K. pneumoniae ST11 strain generated in this study will offer a more benign and readily genetically modifiable model organism for future extensive functional studies. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Antimicrobial Resistance in the Food Chain: A Review

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Verraes, Claire; Van Boxstael, Sigrid; Van Meervenne, Eva; Van Coillie, Els; Butaye, Patrick; Catry, Boudewijn; de Schaetzen, Marie-Athénaïs; Van Huffel, Xavier; Imberechts, Hein; Dierick, Katelijne; Daube, George; Saegerman, Claude; De Block, Jan; Dewulf, Jeroen; Herman, Lieve

2013-01-01

Antimicrobial resistant zoonotic pathogens present on food constitute a direct risk to public health. Antimicrobial resistance genes in commensal or pathogenic strains form an indirect risk to public health, as they increase the gene pool from which pathogenic bacteria can pick up resistance traits. Food can be contaminated with antimicrobial resistant bacteria and/or antimicrobial resistance genes in several ways. A first way is the presence of antibiotic resistant bacteria on food selected by the use of antibiotics during agricultural production. A second route is the possible presence of resistance genes in bacteria that are intentionally added during the processing of food (starter cultures, probiotics, bioconserving microorganisms and bacteriophages). A last way is through cross-contamination with antimicrobial resistant bacteria during food processing. Raw food products can be consumed without having undergone prior processing or preservation and therefore hold a substantial risk for transfer of antimicrobial resistance to humans, as the eventually present resistant bacteria are not killed. As a consequence, transfer of antimicrobial resistance genes between bacteria after ingestion by humans may occur. Under minimal processing or preservation treatment conditions, sublethally damaged or stressed cells can be maintained in the food, inducing antimicrobial resistance build-up and enhancing the risk of resistance transfer. Food processes that kill bacteria in food products, decrease the risk of transmission of antimicrobial resistance. PMID:23812024

Electrical Resistivity Measurements: a Review

Science.gov (United States)

Singh, Yadunath

World-wide interest on the use of ceramic materials for aerospace and other advanced engineering applications, has led to the need for inspection techniques capable of detecting unusually electrical and thermal anomalies in these compounds. Modern ceramic materials offer many attractive physical, electrical and mechanical properties for a wide and rapidly growing range of industrial applications; moreover specific use may be made of their electrical resistance, chemical resistance, and thermal barrier properties. In this review, we report the development and various techniques for the resistivity measurement of solid kind of samples.

Clostridium difficile Infection and Patient-Specific Antimicrobial Resistance Testing Reveals a High Metronidazole Resistance Rate.

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Barkin, Jodie A; Sussman, Daniel A; Fifadara, Nimita; Barkin, Jamie S

2017-04-01

Clostridium difficile (CD) infection (CDI) causes marked morbidity and mortality, accounting for large healthcare expenditures annually. Current CDI treatment guidelines focus on clinical markers of patient severity to determine the preferred antibiotic regimen of metronidazole versus vancomycin. The antimicrobial resistance patterns for patients with CD are currently unknown. The aim of this study was to define the antimicrobial resistance patterns for CD. This study included all patients with stools sent for CD testing to a private laboratory (DRG Laboratory, Alpharetta, Georgia) in a 6-month period from across the USA. Patient data was de-identified, with only age, gender, and zip-code available per laboratory protocol. All samples underwent PCR testing followed by hybridization for CD toxin regions A and B. Only patients with CD-positive PCR were analyzed. Antimicrobial resistance testing using stool genomic DNA evaluated presence of imidazole- and vancomycin-resistant genes using multiplex PCR gene detection. Of 2743, 288 (10.5%) stool samples were positive for CD. Six were excluded per protocol. Of 282, 193 (69.4%) were women, and average age was 49.4 ± 18.7 years. Of 282, 62 were PCR positive for toxins A and B, 160 for toxin A positive alone, and 60 for toxin B positive alone. Antimicrobial resistance testing revealed 134/282 (47.5%) patients resistant to imidazole, 17 (6.1%) resistant to vancomycin, and 9 (3.2%) resistant to imidazole and vancomycin. CD-positive patients with presence of imidazole-resistant genes from stool DNA extract was a common phenomenon, while vancomycin resistance was uncommon. Similar to treatment of other infections, antimicrobial resistance testing should play a role in CDI clinical decision-making algorithms to enable more expedited and cost-effective delivery of patient care.

Cladophialophora psammophila, a novel species of Chaetothyriales with a potential use in the bioremediation of volatile aromatic hydrocarbons

NARCIS (Netherlands)

Badali, H.; Prenafata - Boldu, F.X.; Guarro, J.; Klaasen, C.; Meis, J.F.; de Hoog, G.S.

2011-01-01

Cladophialophora is a genus of asexual black yeast-like fungi with one-celled, hydrophobic conidia which is predicted to have teleomorphs in the ascomycete genus Capronia, a member of the order Chaetothyriales. Cladophialophora species are relatively frequently involved in human disease ranging from

The ascomycete genus Sordaria

OpenAIRE

Guarro, J.; Arx, von, J.A.

1987-01-01

Sordaria is restricted to coprophilous, soil-, or seed-borne Pyrenomycetes with aseptate, elongate ascospores with a gelatinous, amorphous sheath. The genus is redescribed and a key to fourteen accepted species is given. A checklist of all taxa described as Sordaria is added.

Phenotypic low-level isoniazid resistance as a marker to predict ethionamide resistance in Mycobacterium tuberculosis

Directory of Open Access Journals (Sweden)

Salima Qamar

2017-01-01

Full Text Available Background: Tuberculosis is one of the most prevalent diseases in Pakistan. Pakistan has the highest burden of MDR-TB in the Eastern Mediterranean region. Ethionamide is an anti-tuberculous drug frequently used to treat MDR-TB. Its drug susceptibility testing is not easily available in resource limited settings. Since it acts on the same target protein as isoniazid (inhA protein encoded by inhA gene, we sought to find out if phenotypic isoniazid resistance can be a marker of ethionamide resistance. Materials and Methods: This was a retrospective observational study conducted at the Aga Khan University hospital section of microbiology. Data was retrieved between 2011 to 2014 for all culture positive MTB strains. All culture positive MTB isolates with susceptibilities to isoniazid and ethionamide recorded were included in the study. Isoniazid and ethionamide susceptibilities were performed using agar proportion method on Middlebrook 7H10 agar. Rate of Ethionamide resistance between low-level isoniazid resistant, high level isoniazid resistant and isoniazid sensitive MTB was compared. Results: A total of 11,274 isolates were included in the study. A statistically significant association (P < 0.001 was found between Ethionamide resistance and low-level isoniazid resistance (26.6% as compared to high-level isoniazid resistance (8.85% and isoniazid sensitivity (0.71% in MTB strains. However this association was not seen in XDR-TB strains. Conclusion: Low level isoniazid resistance may be used as marker for phenotypic ethionamide resistance and hence guide clinicians' choice of antituberculous agent for MDR-TB in Pakistan. Further studies involving detection of genotypic association of isoniazid and ethionamide susceptibilities are needed before a final conclusion can be derived.

[Resistance risk, cross-resistance and biochemical resistance mechanism of Laodelphax striatellus to buprofezin].

Science.gov (United States)

Mao, Xu-lian; Liu, Jin; Li, Xu-ke; Chi, Jia-jia; Liu, Yong-jie

2016-01-01

In order to investigate the resistance development law and biochemical resistance mechanism of Laodelphax striatellus to buprofezin, spraying rice seedlings was used to continuously screen resistant strains of L. striatellus and dipping rice seedlings was applied to determine the toxicity and cross-resistance of L. striatellus to insecticides. After 32-generation screening with buprofezin, L. striatellus developed 168.49 folds resistance and its reality heritability (h2) was 0.11. If the killing rate was 80%-90%, L. striatellus was expected to develop 10-fold resistance to buprofezin only after 5 to 6 generations breeding. Because the actual reality heritability of field populations was usually lower than that of the resistant strains, the production of field populations increasing with 10-fold resistance would need much longer time. The results of cross-resistance showed that resistant strain had high level cross-resistance with thiamethoxam and imidacloprid, low level cross-resistance with acetamiprid, and no cross-resistance with pymetrozine and chlorpyrifos. The activity of detoxification enzymes of different strains and the syergism of synergist were measured. The results showed that cytochrome P450 monooxygenase played a major role in the resistance of L. striatellus to buprofezin, the esterase played a minor role and the GSH-S-transferase had no effect. Therefore, L. striatellus would have high risk to develop resistance to buprofezin when used in the field and might be delayed by using pymetrozine and chlorpyrifos.

Bulgecin A as a β-lactam enhancer for carbapenem-resistant Pseudomonas aeruginosa and carbapenem-resistant Acinetobacter baumannii clinical isolates containing various resistance mechanisms.

Science.gov (United States)

Skalweit, Marion J; Li, Mei

2016-01-01

Genetic screening of Pseudomonas aeruginosa (PSDA) and Acinetobacter baumannii (ACB) reveals genes that confer increased susceptibility to β-lactams when disrupted, suggesting novel drug targets. One such target is lytic transglycosylase. Bulgecin A (BlgA) is a natural product of Pseudomonas mesoacidophila and a lytic transglycosolase inhibitor that works synergistically with β-lactams targeting PBP3 for Enterobacteriaceae. BlgA also weakly inhibits di-Zn 2+ metallo-β-lactamases like L1 of Stenotrophomonas maltophilia . We hypothesized that because of its unique mechanism of action, BlgA could restore susceptibility to carbapenems in carbapenem-resistant PSDA (CR-PSDA) and carbapenem-resistant ACB, as well as ACB resistant to sulbactam. A BlgA-containing extract was prepared using a previously published protocol. CR-PSDA clinical isolates demonstrating a variety of carbapenem resistance mechanisms (VIM-2 carbapenemases, efflux mechanisms, and AmpC producer expression) were characterized with agar dilution minimum inhibitory concentration (MIC) testing and polymerase chain reaction. Growth curves using these strains were prepared using meropenem, BlgA extract, and meropenem plus BlgA extract. A concentrated Blg A extract combined with low concentrations of meropenem, was able to inhibit the growth of clinical strains of CR-PSDA for strains that had meropenem MICs ≥8 mg/L by agar dilution, and a clinical strain of an OXA-24 producing ACB that had a meropenem MIC >32 mg/L and intermediate ampicillin/sulbactam susceptibility. Similar experiments were conducted on a TEM-1 producing ACB strain resistant to sulbactam. BlgA with ampicillin/sulbactam inhibited the growth of this organism. As in Enterobacteriaceae, BlgA appears to restore the efficacy of meropenem in suppressing the growth of CR-PSDA and carbapenem-resistant ACB strains with a variety of common carbapenem resistance mechanisms. BlgA extract also inhibits VIM-2 β-lactamase in vitro. BlgA may prove to be

Mutation of environmental mycobacteria to resist silver nanoparticles also confers resistance to a common antibiotic.

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Larimer, Curtis; Islam, Mohammad Shyful; Ojha, Anil; Nettleship, Ian

2014-08-01

Non-tuberculous mycobacteria are a threat to human health, gaining entry to the body through contaminated water systems, where they form persistent biofilms despite extensive attempts at disinfection. Silver is a natural antibacterial agent and in nanoparticle form activity is increased by a high surface area. Silver nanoparticles (AgNPs) have been used as alternative disinfectants in circulating water systems, washing machines and even clothing. However, nanoparticles, like any other antibiotic that has a pervasive durable presence, carry the risk of creating a resistant population. In this study Mycobacterium smegmatis strain mc(2)155 was cultured in AgNP enriched agar such that only a small population survived. Surviving cultures were isolated and re-exposed to AgNPs and AgNO3 and resistance to silver was compared to a negative control. After only a single exposure, mutant M. smegmatis populations were resistant to AgNPs and AgNO3. Further, the silver resistant mutants were exposed to antibiotics to determine if general resistance had been conferred. The minimum inhibitory concentration of isoniazid was four times higher for silver resistant mutants than for strain mc(2)155. However, core resistance was not conferred to other toxic metal ions. The mutants had lower resistance to CuSO4 and ZnSO4 than the mc(2)155 strain.

Antimicrobial resistance 1979-2009 at Karolinska hospital, Sweden: normalized resistance interpretation during a 30-year follow-up on Staphylococcus aureus and Escherichia coli resistance development.

Science.gov (United States)

Kronvall, Göran

2010-09-01

To utilize a material of inhibition zone diameter measurements from disc diffusion susceptibility tests between 1979 and 2009, an objective setting of epidemiological breakpoints was necessary because of methodological changes. Normalized resistance interpretation (NRI) met this need and was applied to zone diameter histograms for Staphylococcus aureus and Escherichia coli isolates. The results confirmed a slow resistance development as seen in Northern countries. The S. aureus resistance levels for erythromycin, clindamycin and fusidic acid in 2009 were 3.2%, 1.8% and 1.4% with denominator correction. A rise in resistance to four antimicrobials in 1983 was probably because of a spread of resistant Methicillin Susceptible Staphylococcus Aureus (MSSA). For E. coli, the denominator-corrected resistance levels in 2009 were 27% for ampicillin, around 3% for third-generation cephalosporins, 0.1% for imipenem, 2.5% for gentamicin, 19% for trimethoprim, 4.5% for co-trimoxazole, 1.2% for nitrofurantoin and 9% for ciprofloxacin. The temporal trends showed a rise in fluoroquinolone resistance from 1993, a parallel increase in gentamicin resistance, a substantial increase in trimethoprim and sulphonamide resistance in spite of decreased consumption, and a steady rise in ampicillin resistance from a constant level before 1989. A short review of global resistance surveillance studies is included.

Dolabra nepheliae on rambutan and lychee represents a novel lineage of phytopathogenic Eurotiomycetes.

Science.gov (United States)

Rossman, Amy Y; Schoch, Conrad L; Farr, David F; Nishijima, Kate; Keith, Lisa; Goenaga, Ricardo

2010-07-01

Rambutan (Nephelium lappaceum) and lychee (Litchi chinensis) are tropical trees in the Sapindaceae that produce delicious edible fruits and are increasingly cultivated in tropical regions. These trees are afflicted with a stem canker disease associated with the ascomycete Dolabra nepheliae. Previously known from Asia and Australia, this fungus was recently reported from Hawaii and Puerto Rico. The sexual and asexual states of Dolabra nepheliae are redescribed and illustrated. In addition, the ITS and large subunit of the nuclear ribosomal DNA plus fragments from the genes RPB2, TEF1, and the mitochondrial small ribosomal subunit were sequenced for three isolates of D. nepheliae and compared with other sequences of ascomycetes. It was determined that D. nepheliae represents a new lineage within the Eurotiomycetes allied with Phaeomoniella chlamydospora, the causal agent of Petri grapevine decline.

A nonlinear HP-type complementary resistive switch

Directory of Open Access Journals (Sweden)

Paul K. Radtke

2016-05-01

Full Text Available Resistive Switching (RS is the change in resistance of a dielectric under the influence of an external current or electric field. This change is non-volatile, and the basis of both the memristor and resistive random access memory. In the latter, high integration densities favor the anti-serial combination of two RS-elements to a single cell, termed the complementary resistive switch (CRS. Motivated by the irregular shape of the filament protruding into the device, we suggest a nonlinearity in the resistance-interpolation function, characterized by a single parameter p. Thereby the original HP-memristor is expanded upon. We numerically simulate and analytically solve this model. Further, the nonlinearity allows for its application to the CRS.

A nonlinear HP-type complementary resistive switch

Science.gov (United States)

Radtke, Paul K.; Schimansky-Geier, Lutz

2016-05-01

Resistive Switching (RS) is the change in resistance of a dielectric under the influence of an external current or electric field. This change is non-volatile, and the basis of both the memristor and resistive random access memory. In the latter, high integration densities favor the anti-serial combination of two RS-elements to a single cell, termed the complementary resistive switch (CRS). Motivated by the irregular shape of the filament protruding into the device, we suggest a nonlinearity in the resistance-interpolation function, characterized by a single parameter p. Thereby the original HP-memristor is expanded upon. We numerically simulate and analytically solve this model. Further, the nonlinearity allows for its application to the CRS.

Molecular cloning and characterization of a ToxA-like gene from the maize pathogen Cochliobolus heterostrophus

Science.gov (United States)

ToxA, the first discovered fungal proteinaceous host-selective toxin, was originally identified from the tan spot fungus Pyrenophora tritici-repentis (Ptr). Homologues of the PtrToxA gene have not been identified from any other ascomycetes except the leaf/glume blotch fungus Stagonospora nodorum, w...

Organization of a resistance gene cluster linked to rhizomania resistance in sugar beet

Science.gov (United States)

Genetic resistance to rhizomania has been in use for over 40 years. Characterization of the molecular basis for susceptibility and resistance has proved challenging. Nucleotide-binding leucine-rich-repeat-containing (NB-LRR) genes have been implicated in numerous gene-for-gene resistance interaction...

Rapid diagnosis of pyrazinamide-resistant multidrug-resistant tuberculosis using a molecular-based diagnostic algorithm.

Science.gov (United States)

Simons, S O; van der Laan, T; Mulder, A; van Ingen, J; Rigouts, L; Dekhuijzen, P N R; Boeree, M J; van Soolingen, D

2014-10-01

There is an urgent need for rapid and accurate diagnosis of pyrazinamide-resistant multidrug-resistant tuberculosis (MDR-TB). No diagnostic algorithm has been validated in this population. We hypothesized that pncA sequencing added to rpoB mutation analysis can accurately identify patients with pyrazinamide-resistant MDR-TB. We identified from the Dutch national database (2007-11) patients with a positive Mycobacterium tuberculosis culture containing a mutation in the rpoB gene. In these cases, we prospectively sequenced the pncA gene. Results from the rpoB and pncA mutation analysis (pncA added to rpoB) were compared with phenotypic susceptibility testing results to rifampicin, isoniazid and pyrazinamide (reference standard) using the Mycobacterial Growth Indicator Tube 960 system. We included 83 clinical M. tuberculosis isolates containing rpoB mutations in the primary analysis. Rifampicin resistance was seen in 72 isolates (87%), isoniazid resistance in 73 isolates (88%) and MDR-TB in 65 isolates (78%). Phenotypic reference testing identified pyrazinamide-resistant MDR-TB in 31 isolates (48%). Sensitivity of pncA sequencing added to rpoB mutation analysis for detecting pyrazinamide-resistant MDR-TB was 96.8%, the specificity was 94.2%, the positive predictive value was 90.9%, the negative predictive value was 98.0%, the positive likelihood was 16.8 and the negative likelihood was 0.03. In conclusion, pyrazinamide-resistant MDR-TB can be accurately detected using pncA sequencing added to rpoB mutation analysis. We propose to include pncA sequencing in every isolate with an rpoB mutation, allowing for stratification of MDR-TB treatment according to pyrazinamide susceptibility. © 2014 The Authors Clinical Microbiology and Infection © 2014 European Society of Clinical Microbiology and Infectious Diseases.

Biological characterization of fenpicoxamid, a new fungicide with utility in cereals and other crops.

Science.gov (United States)

Owen, W John; Yao, Chenglin; Myung, Kyung; Kemmitt, Greg; Leader, Andrew; Meyer, Kevin G; Bowling, Andrew J; Slanec, Thomas; Kramer, Vincent J

2017-10-01

The development of novel highly efficacious fungicides that lack cross-resistance is extremely desirable. Fenpicoxamid (Inatreq™ active) possesses these characteristics and is a member of a novel picolinamide class of fungicides derived from the antifungal natural product UK-2A. Fenpicoxamid strongly inhibited in vitro growth of several ascomycete fungi, including Zymoseptoria tritici (EC 50 , 0.051 mg L -1 ). Fenpicoxamid is converted by Z. tritici to UK-2A, a 15-fold stronger inhibitor of Z. tritici growth (EC 50 , 0.0033 mg L -1 ). Strong fungicidal activity of fenpicoxamid against driver cereal diseases was confirmed in greenhouse tests, where activity on Z. tritici and Puccinia triticina matched that of fluxapyroxad. Due to its novel target site (Q i site of the respiratory cyt bc1 complex) for the cereals market, fenpicoxamid is not cross-resistant to Z. tritici isolates resistant to strobilurin and/or azole fungicides. Across multiple European field trials Z. tritici was strongly controlled (mean, 82%) by 100 g as ha -1 applications of fenpicoxamid, which demonstrated excellent residual activity. The novel chemistry and biochemical target site of fenpicoxamid as well as its lack of cross-resistance and strong efficacy against Z. tritici and other pathogens highlight the importance of fenpicoxamid as a new tool for controlling plant pathogenic fungi. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2017 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Resistive flex sensors: a survey

International Nuclear Information System (INIS)

Saggio, Giovanni; Riillo, Francesco; Sbernini, Laura; Quitadamo, Lucia Rita

2016-01-01

Resistive flex sensors can be used to measure bending or flexing with relatively little effort and a relatively low budget. Their lightness, compactness, robustness, measurement effectiveness and low power consumption make these sensors useful for manifold applications in diverse fields. Here, we provide a comprehensive survey of resistive flex sensors, taking into account their working principles, manufacturing aspects, electrical characteristics and equivalent models, useful front-end conditioning circuitry, and physic-bio-chemical aspects. Particular effort is devoted to reporting on and analyzing several applications of resistive flex sensors, related to the measurement of body position and motion, and to the implementation of artificial devices. In relation to the human body, we consider the utilization of resistive flex sensors for the measurement of physical activity and for the development of interaction/interface devices driven by human gestures. Concerning artificial devices, we deal with applications related to the automotive field, robots, orthosis and prosthesis, musical instruments and measuring tools. The presented literature is collected from different sources, including bibliographic databases, company press releases, patents, master’s theses and PhD theses. (topical review)

Resistive flex sensors: a survey

Science.gov (United States)

Saggio, Giovanni; Riillo, Francesco; Sbernini, Laura; Quitadamo, Lucia Rita

2016-01-01

Resistive flex sensors can be used to measure bending or flexing with relatively little effort and a relatively low budget. Their lightness, compactness, robustness, measurement effectiveness and low power consumption make these sensors useful for manifold applications in diverse fields. Here, we provide a comprehensive survey of resistive flex sensors, taking into account their working principles, manufacturing aspects, electrical characteristics and equivalent models, useful front-end conditioning circuitry, and physic-bio-chemical aspects. Particular effort is devoted to reporting on and analyzing several applications of resistive flex sensors, related to the measurement of body position and motion, and to the implementation of artificial devices. In relation to the human body, we consider the utilization of resistive flex sensors for the measurement of physical activity and for the development of interaction/interface devices driven by human gestures. Concerning artificial devices, we deal with applications related to the automotive field, robots, orthosis and prosthesis, musical instruments and measuring tools. The presented literature is collected from different sources, including bibliographic databases, company press releases, patents, master’s theses and PhD theses.

Genetic makeup of amantadine-resistant and oseltamivir-resistant human influenza A/H1N1 viruses.

Science.gov (United States)

Zaraket, Hassan; Saito, Reiko; Suzuki, Yasushi; Baranovich, Tatiana; Dapat, Clyde; Caperig-Dapat, Isolde; Suzuki, Hiroshi

2010-04-01

The emergence and widespread occurrence of antiviral drug-resistant seasonal human influenza A viruses, especially oseltamivir-resistant A/H1N1 virus, are major concerns. To understand the genetic background of antiviral drug-resistant A/H1N1 viruses, we performed full genome sequencing of prepandemic A/H1N1 strains. Seasonal influenza A/H1N1 viruses, including antiviral-susceptible viruses, amantadine-resistant viruses, and oseltamivir-resistant viruses, obtained from several areas in Japan during the 2007-2008 and 2008-2009 influenza seasons were analyzed. Sequencing of the full genomes of these viruses was performed, and the phylogenetic relationships among the sequences of each individual genome segment were inferred. Reference genome sequences from the Influenza Virus Resource database were included to determine the closest ancestor for each segment. Phylogenetic analysis revealed that the oseltamivir-resistant strain evolved from a reassortant oseltamivir-susceptible strain (clade 2B) which circulated in the 2007-2008 season by acquiring the H275Y resistance-conferring mutation in the NA gene. The oseltamivir-resistant lineage (corresponding to the Northern European resistant lineage) represented 100% of the H1N1 isolates from the 2008-2009 season and further acquired at least one mutation in each of the polymerase basic protein 2 (PB2), polymerase basic protein 1 (PB1), hemagglutinin (HA), and neuraminidase (NA) genes. Therefore, a reassortment event involving two distinct oseltamivir-susceptible lineages, followed by the H275Y substitution in the NA gene and other mutations elsewhere in the genome, contributed to the emergence of the oseltamivir-resistant lineage. In contrast, amantadine-resistant viruses from the 2007-2008 season distinctly clustered in clade 2C and were characterized by extensive amino acid substitutions across their genomes, suggesting that a fitness gap among its genetic components might have driven these mutations to maintain it in the

Drug Resistance versus Spiritual Resistance: A Comparative Analysis from the Perspective of Spiritual Health

Directory of Open Access Journals (Sweden)

Mohammad Baqer Mohammadi Laini

2014-12-01

Full Text Available Background and Objectives: Taking into account a few principles concerning human being, it becomes plausible that the human spirit would also have a similar reaction to spiritual “medicine” provided to it. In order to better understand how this is possible, we must consider the means by which the human spirit becomes resistant to spiritual remedies and compare them with the resistance developed by the body against physical drugs. As such, this research aimed at creating a comparative analysis between the elements that cause the human spirit to become resistant against spiritual remedies in comparison to the body’s resistance against physical treatments (e.g. drugs and other physical treatment. Methods: The research at hand highlights the conclusions of an overall study of the Holy Quran, books of Islamic narration, and extensive Internet research concerning this subject. With these resources, the various aspects of the spirit’s resistance against spiritual remedies were discussed in detail. Results: According to Holy Quran and Islamic narrations: Based on the expectations which God has of man, his heart (i.e. spirit has the potential to fall under one of two categories – positive or negative. An afflicted heart may at times, like an afflicted body, become resistant against a remedy designed to cure it. In both cases of physical or metaphysical resistance, the underlying element that causes this resistance as well as the symptoms which accompany it are similar to one another. Having considered the teachings found in religious texts, this research discovered the underlying causes of spiritual resistance, and outlined some solutions which can prevent this issue from arising in the first place. Conclusion: Based on the standards of health and spiritual wellbeing as outlined in Holy Quran, it is said that some hearts are unhealthy and require treatment and healing. In Holy Quran, there is also no doubt in it, guidance to the God wary

Drug-resistant gram-negative uropathogens: A review.

Science.gov (United States)

Khoshnood, Saeed; Heidary, Mohsen; Mirnejad, Reza; Bahramian, Aghil; Sedighi, Mansour; Mirzaei, Habibollah

2017-10-01

Urinary tract infection(UTI) caused by Gram-negative bacteria is the second most common infectious presentation in community medical practice. Approximately 150 million people are diagnosed with UTI each year worldwide. Drug resistance in Gram-negative uropathogens is a major global concern which can lead to poor clinical outcomes including treatment failure, development of bacteremia, requirement for intravenous therapy, hospitalization, and extended length of hospital stay. The mechanisms of drug resistance in these bacteria are important due to they are often not identified by routine susceptibility tests and have an exceptional potential for outbreaks. Treatment of UTIs depends on the access to effective drugs, which is now threatened by antibiotic resistant Gram-negative uropathogens. Although several effective antibiotics with activity against highly resistant Gram-negatives are available, there is not a unique antibiotic with activity against the high variety of resistance. Therefore, antimicrobial susceptibility tests, correlation between clinicians and laboratories, development of more rapid diagnostic methods, and continuous monitoring of drug resistance are urgent priorities. In this review, we will discuss about the current global status of drug-resistant Gram-negative uropathogens and their mechanisms of drug resistance to provide new insights into their treatment options. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Antimicrobial resistance, heavy metal resistance and integron content in bacteria isolated from a South African tilapia aquaculture system.

Science.gov (United States)

Chenia, Hafizah Y; Jacobs, Anelet

2017-11-21

Antibacterial compounds and metals co-select for antimicrobial resistance when bacteria harbour resistance genes towards both types of compounds, facilitating the proliferation and evolution of antimicrobial and heavy metal resistance. Antimicrobial and heavy metal resistance indices of 42 Gram-negative bacteria from a tilapia aquaculture system were determined to identify possible correlations between these phenotypes. Agar dilution assays were carried out to determine susceptibility to cadmium, copper, lead, mercury, chromate and zinc, while susceptibility to 21 antimicrobial agents was investigated by disk diffusion assays. Presence of merA, the mercury resistance gene, was determined by dot-blot hybridizations and PCR. Association of mercury resistance with integrons and transposon Tn21 was also investigated by PCR. Isolates displayed a high frequency of antimicrobial (erythromycin: 100%; ampicillin: 85%; trimethoprim: 78%) and heavy metal (Zn2+: 95%; Cd2+: 91%) resistance. No correlation was established between heavy metal and multiple antibiotic resistance indices. Significant positive correlations were observed between heavy metal resistance profiles, indices, Cu2+ and Cr3+ resistance with erythromycin resistance. Significant positive correlations were observed between merA (24%)/Tn21 (24%) presence and heavy metal resistance profiles and indices; however, significant negative correlations were obtained between integron-associated qacE∆1 (43%) and sulI (26%) gene presence and heavy metal resistance indices. Heavy metal and antimicrobial agents co-select for resistance, with fish-associated, resistant bacteria demonstrating simultaneous heavy metal resistance. Thus, care should be taken when using anti-fouling heavy metals as feed additives in aquaculture facilities.

Emergence of fluoroquinolone resistance among drug resistant tuberculosis patients at a tertiary care facility in Karachi, Pakistan.

Science.gov (United States)

Zaidi, Syed Mohammad Asad; Haseeb, Abdul; Habib, Shifa Salman; Malik, Amyn; Khowaja, Saira; SaifUllah, Nausheen; Rizvi, Nadeem

2017-07-25

Pakistan is classified as one of the high multi-drug resistant tuberculosis (MDR-TB) burden countries. A poorly regulated private sector, over-prescription of antibiotics and self-medication has led to augmented rates of drug-resistance in the country. Pakistan's first national anti-tuberculosis drug resistance survey identified high prevalence of fluoroquinolone resistance among MDR-TB patients. Further institutional evidence of fluoroquinolone drug-resistance can support re-evaluation of treatment regimens as well as invigorate efforts to control antibiotic resistance in the country. In this study, data for drug-susceptibility testing (DST) was retrospectively analyzed for a total of 133 patients receiving MDR-TB treatment at the Chest Department of Jinnah Postgraduate Medical Center, Karachi, Pakistan. Frequency analyses for resistance patterns was carried out and association of fluoroquinolone (ofloxacin) resistance with demographics and past TB treatment category were assessed. Within first-line drugs, resistance to isoniazid was detected in 97.7% of cases, followed by rifampicin (96.9%), pyrazinamide (86.4%), ethambutol (69.2%) and streptomycin (64.6%). Within second-line drugs, ofloxacin resistance was detected in 34.6% of cases. Resistance to ethionamide and amikacin was 2.3% and 1.6%, respectively. Combined resistance of oflaxacin and isoniazid was detected in 33.9% of cases. Age, gender and past TB treatment category were not significantly associated with resistance to ofloxacin. Fluoroquinolone resistance was observed in an alarmingly high proportion of MDR-TB cases. Our results suggest caution in their use for empirical management of MDR-TB cases and recommended treatment regimens for MDR-TB may require re-evaluation. Greater engagement of private providers and stringent pharmacy regulations are urgently required.

Cry1F resistance among lepidopteran pests: a model for improved resistance management?

Science.gov (United States)

Vélez, Ana M; Vellichirammal, Neetha Nanoth; Jurat-Fuentes, Juan Luis; Siegfried, Blair D

2016-06-01

The Cry1Fa protein from the bacterium Bacillus thuringiensis (Bt) is known for its potential to control lepidopteran pests, especially through transgenic expression in maize and cotton. The maize event TC1507 expressing the cry1Fa toxin gene became commercially available in the United States in 2003 for the management of key lepidopteran pests including the European corn borer, Ostrinia nubilalis, and the fall armyworm, Spodoptera frugiperda. A high-dose/refuge strategy has been widely adopted to delay evolution of resistance to event TC1507 and other transgenic Bt crops. Efficacy of this strategy depends on the crops expressing a high dose of the Bt toxin to targeted pests and adjacent refuges of non-Bt host plants serving as a source of abundant susceptible insects. While this strategy has proved effective in delaying O. nubilalis resistance, field-evolved resistance to event TC1507 has been reported in S. frugiperda populations in Puerto Rico, Brazil, and the southeastern United States. This paper examines available information on resistance to Cry1Fa in O. nubilalis and S. frugiperda and discusses how this information identifies opportunities to refine resistance management recommendations for Bt maize. Copyright © 2016 Elsevier Inc. All rights reserved.

Methicillin resistant Staphylococcus aureus in Ethiopia: a meta-analysis.

Science.gov (United States)

Eshetie, Setegn; Tarekegn, Fentahun; Moges, Feleke; Amsalu, Anteneh; Birhan, Wubet; Huruy, Kahsay

2016-11-21

The burden of methicillin resistant Staphylococcus aureus is a major public health concern worldwide; however the overall epidemiology of multidrug resistant strains is neither coordinated nor harmonized, particularly in developing countries including Ethiopia. Therefore, the aim of this meta-analysis was to assess the burden of methicillin resistant Staphylococcos aureus and its antibiotic resistance pattern in Ethiopia at large. PubMed, Google Scholar, and lancet databases were searched and a total of 20 studies have been selected for meta-analysis. Six authors have independently extracts data on the prevalence of methicillin resistant Staphylococcus aureus among clinical isolates of Staphylococcus aureus. Statistical analysis was achieved by using Open meta-analyst (version 3.13) and Comprehensive meta-analysis (version 3.3) softwares. The overall prevalence of methicillin resistant Staphylococcus aureus and its antibiotic resistance pattern were pooled by using the forest plot, table and figure with 95% CI. The pooled prevalence of methicillin resistant Staphylococcus aureus was 32.5% (95% CI, 24.1 to 40.9%). Moreover, methicillin resistant Staphylococcus aureus strains were found to be highly resistant to penicillin, ampicillin, erythromycin, and amoxicillin, with a pooled resistance ratio of 99.1, 98.1, 97.2 and 97.1%, respectively. On the other hand, comparably low levels of resistance ratio were noted to vancomycin, 5.3%. The overall burden of methicillin resistant Staphylococcus aureus is considerably high, besides these strains showed extreme resistance to penicillin, ampicillin, erythromycin and amoxicillin. In principle, appropriate use of antibiotics, applying safety precautions are the key to reduce the spread of multidrug resistant strains, methicillin resistant Staphylococcus aureus in particular.

Genetics Home Reference: type A insulin resistance syndrome

Science.gov (United States)

... Conditions Type A insulin resistance syndrome Type A insulin resistance syndrome Printable PDF Open All Close All Enable ... view the expand/collapse boxes. Description Type A insulin resistance syndrome is a rare disorder characterized by severe ...

Resistance Status and Resistance Mechanisms in a Strain of Aedes aegypti (Diptera: Culicidae) From Puerto Rico.

Science.gov (United States)

Estep, Alden S; Sanscrainte, Neil D; Waits, Christy M; Louton, Jessica E; Becnel, James J

2017-11-07

Puerto Rico (PR) has a long history of vector-borne disease and insecticide-resistant Aedes aegypti (L.). Defining contributing mechanisms behind phenotypic resistance is critical for effective vector control intervention. However, previous studies from PR have each focused on only one mechanism of pyrethroid resistance. This study examines the contribution of P450-mediated enzymatic detoxification and sodium channel target site changes to the overall resistance phenotype of Ae. aegypti collected from San Juan, PR, in 2012. Screening of a panel of toxicants found broad resistance relative to the lab susceptible Orlando (ORL1952) strain. We identified significant resistance to representative Type I, Type II, and nonester pyrethroids, a sodium channel blocker, and a sodium channel blocking inhibitor, all of which interact with the sodium channel. Testing of fipronil, a chloride channel agonist, also showed low but significant levels of resistance. In contrast, the PR and ORL1952 strains were equally susceptible to chlorfenapyr, which has been suggested as an alternative public health insecticide. Molecular characterization of the strain indicated that two common sodium channel mutations were fixed in the population. Topical bioassay with piperonyl butoxide (PBO) indicated cytochrome P450-mediated detoxification accounts for approximately half of the resistance profile. Transcript expression screening of cytochrome P450s and glutathione-S-transferases identified the presence of overexpressed transcripts. This study of Puerto Rican Ae. aegypti with significant contributions from both genetic changes and enzymatic detoxification highlights the necessity of monitoring for resistance but also defining the multiple resistance mechanisms to inform effective mosquito control. Published by Oxford University Press on behalf of Entomological Society of America 2017. This work is written by US Government employees and is in the public domain in the US.

Genetic transformation of the white-rot fungus Dichomitus squalens using a new commercial protoplasting cocktail.

Science.gov (United States)

Daly, Paul; Slaghek, Gillian G; Casado López, Sara; Wiebenga, Ad; Hilden, Kristiina S; de Vries, Ronald P; Mäkelä, Miia R

2017-12-01

D. squalens, a white-rot fungus that efficiently degrades lignocellulose in nature, can be used in various biotechnological applications and has several strains with sequenced and annotated genomes. Here we present a method for the transformation of this basidiomycete fungus, using a recently introduced commercial ascomycete protoplasting enzyme cocktail, Protoplast F. In protoplasting of D. squalens mycelia, Protoplast F outperformed two other cocktails while releasing similar amounts of protoplasts to a third cocktail. The protoplasts released using Protoplast F had a regeneration rate of 12.5% (±6 SE). Using Protoplast F, the D. squalens monokaryon CBS464.89 was conferred with resistance to the antibiotics hygromycin and G418 via polyethylene glycol mediated protoplast transformation with resistance cassettes expressing the hygromycin phosphotransferase (hph) and neomycin phosphotransferase (nptII) genes, respectively. The hph gene was expressed in D. squalens using heterologous promoters from genes encoding β-tubulin or glyceraldehyde 3-phosphate dehydrogenase. A Southern blot confirmed integration of a resistance cassette into the D. squalens genome. An average of six transformants (±2 SE) were obtained when at least several million protoplasts were used (a transformation efficiency of 0.8 (±0.3 SE) transformants per μg DNA). Transformation of D. squalens demonstrates the suitability of the Protoplast F cocktail for basidiomycete transformation and furthermore can facilitate understanding of basidiomycete gene function and development of improved strains for biotechnological applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Triazole Resistance in Aspergillus spp.: A Worldwide Problem?

Science.gov (United States)

Rivero-Menendez, Olga; Alastruey-Izquierdo, Ana; Mellado, Emilia; Cuenca-Estrella, Manuel

2016-01-01

Since the first description of an azole-resistant A. fumigatus strain in 1997, there has been an increasing number of papers describing the emergence of azole resistance. Firstly reported in the USA and soon after in Europe, it has now been described worldwide, challenging the management of human aspergillosis. The main mechanism of resistance is the modification of the azole target enzyme: 14-α sterol demethylase, encoded by the cyp51A gene; although recently, other resistance mechanisms have also been implicated. In addition, a shift in the epidemiology has been noted with other Aspergillus species (mostly azole resistant) increasingly being reported as causative agents of human disease. This paper reviews the current situation of Aspergillus azole resistance and its implications in the clinical setting. PMID:29376938

HIV resistance testing and detected drug resistance in Europe

DEFF Research Database (Denmark)

Schultze, Anna; Phillips, Andrew N; Paredes, Roger

2015-01-01

to Southern Europe. CONCLUSIONS: Despite a concurrent decline in virological failure and testing, drug resistance was commonly detected. This suggests a selective approach to resistance testing. The regional differences identified indicate that policy aiming to minimize the emergence of resistance......OBJECTIVES: To describe regional differences and trends in resistance testing among individuals experiencing virological failure and the prevalence of detected resistance among those individuals who had a genotypic resistance test done following virological failure. DESIGN: Multinational cohort...... study. METHODS: Individuals in EuroSIDA with virological failure (>1 RNA measurement >500 on ART after >6 months on ART) after 1997 were included. Adjusted odds ratios (aORs) for resistance testing following virological failure and aORs for the detection of resistance among those who had a test were...

Tumour resistance to cisplatin: a modelling approach

Energy Technology Data Exchange (ETDEWEB)

Marcu, L [School of Chemistry and Physics, University of Adelaide, North Terrace, SA 5000 (Australia); Bezak, E [School of Chemistry and Physics, University of Adelaide, North Terrace, SA 5000 (Australia); Olver, I [Faculty of Medicine, University of Adelaide, North Terrace, SA 5000 (Australia); Doorn, T van [School of Chemistry and Physics, University of Adelaide, North Terrace, SA 5000 (Australia)

2005-01-07

Although chemotherapy has revolutionized the treatment of haematological tumours, in many common solid tumours the success has been limited. Some of the reasons for the limitations are: the timing of drug delivery, resistance to the drug, repopulation between cycles of chemotherapy and the lack of complete understanding of the pharmacokinetics and pharmacodynamics of a specific agent. Cisplatin is among the most effective cytotoxic agents used in head and neck cancer treatments. When modelling cisplatin as a single agent, the properties of cisplatin only have to be taken into account, reducing the number of assumptions that are considered in the generalized chemotherapy models. The aim of the present paper is to model the biological effect of cisplatin and to simulate the consequence of cisplatin resistance on tumour control. The 'treated' tumour is a squamous cell carcinoma of the head and neck, previously grown by computer-based Monte Carlo techniques. The model maintained the biological constitution of a tumour through the generation of stem cells, proliferating cells and non-proliferating cells. Cell kinetic parameters (mean cell cycle time, cell loss factor, thymidine labelling index) were also consistent with the literature. A sensitivity study on the contribution of various mechanisms leading to drug resistance is undertaken. To quantify the extent of drug resistance, the cisplatin resistance factor (CRF) is defined as the ratio between the number of surviving cells of the resistant population and the number of surviving cells of the sensitive population, determined after the same treatment time. It is shown that there is a supra-linear dependence of CRF on the percentage of cisplatin-DNA adducts formed, and a sigmoid-like dependence between CRF and the percentage of cells killed in resistant tumours. Drug resistance is shown to be a cumulative process which eventually can overcome tumour regression leading to treatment failure.

Tumour resistance to cisplatin: a modelling approach

International Nuclear Information System (INIS)

Marcu, L; Bezak, E; Olver, I; Doorn, T van

2005-01-01

Although chemotherapy has revolutionized the treatment of haematological tumours, in many common solid tumours the success has been limited. Some of the reasons for the limitations are: the timing of drug delivery, resistance to the drug, repopulation between cycles of chemotherapy and the lack of complete understanding of the pharmacokinetics and pharmacodynamics of a specific agent. Cisplatin is among the most effective cytotoxic agents used in head and neck cancer treatments. When modelling cisplatin as a single agent, the properties of cisplatin only have to be taken into account, reducing the number of assumptions that are considered in the generalized chemotherapy models. The aim of the present paper is to model the biological effect of cisplatin and to simulate the consequence of cisplatin resistance on tumour control. The 'treated' tumour is a squamous cell carcinoma of the head and neck, previously grown by computer-based Monte Carlo techniques. The model maintained the biological constitution of a tumour through the generation of stem cells, proliferating cells and non-proliferating cells. Cell kinetic parameters (mean cell cycle time, cell loss factor, thymidine labelling index) were also consistent with the literature. A sensitivity study on the contribution of various mechanisms leading to drug resistance is undertaken. To quantify the extent of drug resistance, the cisplatin resistance factor (CRF) is defined as the ratio between the number of surviving cells of the resistant population and the number of surviving cells of the sensitive population, determined after the same treatment time. It is shown that there is a supra-linear dependence of CRF on the percentage of cisplatin-DNA adducts formed, and a sigmoid-like dependence between CRF and the percentage of cells killed in resistant tumours. Drug resistance is shown to be a cumulative process which eventually can overcome tumour regression leading to treatment failure

Understanding a Resistance to Change: A Challenge for Universities

Science.gov (United States)

Caruth, Gail D.; Caruth, Donald L.

2013-01-01

Change is inevitable. Today more than ever the pace of change is accelerating. Where there is organizational change there will be resistance to this change. To deal with the resistance effectively university administrators must understand the nature and causes of resistance to change. Only by dealing effectively with resistance to change can…

The genome of Botrytis cinerea, a ubiquitous broad host range necrotroph

NARCIS (Netherlands)

Hahn, M.; Viaud, M.; Kan, van J.A.L.

2014-01-01

Botrytis cinerea is a necrotrophic ascomycete, causing serious pre- and postharvest crop losses worldwide on a wide variety of plant species. Considerable research in recent years has unraveled a variety of molecular tools that enables the fungus to invade host tissue, including the secretion of

Insulin resistance and bone: a biological partnership.

Science.gov (United States)

Conte, Caterina; Epstein, Solomon; Napoli, Nicola

2018-04-01

Despite a clear association between type 2 diabetes (T2D) and fracture risk, the pathogenesis of bone fragility in T2D has not been clearly elucidated. Insulin resistance is the primary defect in T2D. Insulin signalling regulates both bone formation and bone resorption, but whether insulin resistance can affect bone has not been established. On the other hand, evidence exists that bone might play a role in the regulation of glucose metabolism. This article reviews the available experimental and clinical evidence on the interplay between bone and insulin resistance. Interestingly, a bilateral relationship between bone and insulin resistance seems to exist that unites them in a biological partnership.

Resistance controllability and variability improvement in a TaO{sub x}-based resistive memory for multilevel storage application

Energy Technology Data Exchange (ETDEWEB)

Prakash, A., E-mail: amitknp@postech.ac.kr, E-mail: amit.knp02@gmail.com, E-mail: hwanghs@postech.ac.kr; Song, J.; Hwang, H., E-mail: amitknp@postech.ac.kr, E-mail: amit.knp02@gmail.com, E-mail: hwanghs@postech.ac.kr [Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang, 790-784 (Korea, Republic of); Deleruyelle, D.; Bocquet, M. [Im2np, UMR CNRS 7334, Aix-Marseille Université, Marseille (France)

2015-06-08

In order to obtain reliable multilevel cell (MLC) characteristics, resistance controllability between the different resistance levels is required especially in resistive random access memory (RRAM), which is prone to resistance variability mainly due to its intrinsic random nature of defect generation and filament formation. In this study, we have thoroughly investigated the multilevel resistance variability in a TaO{sub x}-based nanoscale (<30 nm) RRAM operated in MLC mode. It is found that the resistance variability not only depends on the conductive filament size but also is a strong function of oxygen vacancy concentration in it. Based on the gained insights through experimental observations and simulation, it is suggested that forming thinner but denser conductive filament may greatly improve the temporal resistance variability even at low operation current despite the inherent stochastic nature of resistance switching process.

A re-appraisal of Harknessia (Diaporthales), and the introduction of Harknessiaceae fam. nov.

NARCIS (Netherlands)

Crous, P.W.; Summerell, B.A.; Shivas, R.G.; Carnegie, A.J.; Groenewald, J.Z.

2012-01-01

Harknessiaceae is introduced as a new family in the ascomycete order Diaporthales to accommodate species of Harknessia with their Wuestneia-like teleomorphs. The family is distinguished by having pycnidial conidiomata with brown, furfuraceous margins, brown conidia with hyaline, tube-like basal

β-Carbonic Anhydrases Play a Role in Fruiting Body Development and Ascospore Germination in the Filamentous Fungus Sordaria macrospora

Science.gov (United States)

Elleuche, Skander; Pöggeler, Stefanie

2009-01-01

Carbon dioxide (CO2) is among the most important gases for all organisms. Its reversible interconversion to bicarbonate (HCO3 −) reaches equilibrium spontaneously, but slowly, and can be accelerated by a ubiquitous group of enzymes called carbonic anhydrases (CAs). These enzymes are grouped by their distinct structural features into α-, β-, γ-, δ- and ζ-classes. While physiological functions of mammalian, prokaryotic, plant and algal CAs have been extensively studied over the past years, the role of β-CAs in yeasts and the human pathogen Cryptococcus neoformans has been elucidated only recently, and the function of CAs in multicellular filamentous ascomycetes is mostly unknown. To assess the role of CAs in the development of filamentous ascomycetes, the function of three genes, cas1, cas2 and cas3 (carbonic anhydrase of Sordaria) encoding β-class carbonic anhydrases was characterized in the filamentous ascomycetous fungus Sordaria macrospora. Fluorescence microscopy was used to determine the localization of GFP- and DsRED-tagged CAs. While CAS1 and CAS3 are cytoplasmic enzymes, CAS2 is localized to the mitochondria. To assess the function of the three isoenzymes, we generated knock-out strains for all three cas genes (Δcas1, Δcas2, and Δcas3) as well as all combinations of double mutants. No effect on vegetative growth, fruiting-body and ascospore development was seen in the single mutant strains lacking cas1 or cas3, while single mutant Δcas2 was affected in vegetative growth, fruiting-body development and ascospore germination, and the double mutant strain Δcas1/2 was completely sterile. Defects caused by the lack of cas2 could be partially complemented by elevated CO2 levels or overexpression of cas1, cas3, or a non-mitochondrial cas2 variant. The results suggest that CAs are required for sexual reproduction in filamentous ascomycetes and that the multiplicity of isoforms results in redundancy of specific and non-specific functions. PMID:19365544

Beta-carbonic anhydrases play a role in fruiting body development and ascospore germination in the filamentous fungus Sordaria macrospora.

Directory of Open Access Journals (Sweden)

Skander Elleuche

Full Text Available Carbon dioxide (CO(2 is among the most important gases for all organisms. Its reversible interconversion to bicarbonate (HCO(3 (- reaches equilibrium spontaneously, but slowly, and can be accelerated by a ubiquitous group of enzymes called carbonic anhydrases (CAs. These enzymes are grouped by their distinct structural features into alpha-, beta-, gamma-, delta- and zeta-classes. While physiological functions of mammalian, prokaryotic, plant and algal CAs have been extensively studied over the past years, the role of beta-CAs in yeasts and the human pathogen Cryptococcus neoformans has been elucidated only recently, and the function of CAs in multicellular filamentous ascomycetes is mostly unknown. To assess the role of CAs in the development of filamentous ascomycetes, the function of three genes, cas1, cas2 and cas3 (carbonic anhydrase of Sordaria encoding beta-class carbonic anhydrases was characterized in the filamentous ascomycetous fungus Sordaria macrospora. Fluorescence microscopy was used to determine the localization of GFP- and DsRED-tagged CAs. While CAS1 and CAS3 are cytoplasmic enzymes, CAS2 is localized to the mitochondria. To assess the function of the three isoenzymes, we generated knock-out strains for all three cas genes (Deltacas1, Deltacas2, and Deltacas3 as well as all combinations of double mutants. No effect on vegetative growth, fruiting-body and ascospore development was seen in the single mutant strains lacking cas1 or cas3, while single mutant Deltacas2 was affected in vegetative growth, fruiting-body development and ascospore germination, and the double mutant strain Deltacas1/2 was completely sterile. Defects caused by the lack of cas2 could be partially complemented by elevated CO(2 levels or overexpression of cas1, cas3, or a non-mitochondrial cas2 variant. The results suggest that CAs are required for sexual reproduction in filamentous ascomycetes and that the multiplicity of isoforms results in redundancy of

Beta-carbonic anhydrases play a role in fruiting body development and ascospore germination in the filamentous fungus Sordaria macrospora.

Science.gov (United States)

Elleuche, Skander; Pöggeler, Stefanie

2009-01-01

Carbon dioxide (CO(2)) is among the most important gases for all organisms. Its reversible interconversion to bicarbonate (HCO(3) (-)) reaches equilibrium spontaneously, but slowly, and can be accelerated by a ubiquitous group of enzymes called carbonic anhydrases (CAs). These enzymes are grouped by their distinct structural features into alpha-, beta-, gamma-, delta- and zeta-classes. While physiological functions of mammalian, prokaryotic, plant and algal CAs have been extensively studied over the past years, the role of beta-CAs in yeasts and the human pathogen Cryptococcus neoformans has been elucidated only recently, and the function of CAs in multicellular filamentous ascomycetes is mostly unknown. To assess the role of CAs in the development of filamentous ascomycetes, the function of three genes, cas1, cas2 and cas3 (carbonic anhydrase of Sordaria) encoding beta-class carbonic anhydrases was characterized in the filamentous ascomycetous fungus Sordaria macrospora. Fluorescence microscopy was used to determine the localization of GFP- and DsRED-tagged CAs. While CAS1 and CAS3 are cytoplasmic enzymes, CAS2 is localized to the mitochondria. To assess the function of the three isoenzymes, we generated knock-out strains for all three cas genes (Deltacas1, Deltacas2, and Deltacas3) as well as all combinations of double mutants. No effect on vegetative growth, fruiting-body and ascospore development was seen in the single mutant strains lacking cas1 or cas3, while single mutant Deltacas2 was affected in vegetative growth, fruiting-body development and ascospore germination, and the double mutant strain Deltacas1/2 was completely sterile. Defects caused by the lack of cas2 could be partially complemented by elevated CO(2) levels or overexpression of cas1, cas3, or a non-mitochondrial cas2 variant. The results suggest that CAs are required for sexual reproduction in filamentous ascomycetes and that the multiplicity of isoforms results in redundancy of specific and

Insect symbiosis: derivation of yeast-like endosymbionts within an entomopathogenic filamentous lineage.

Science.gov (United States)

Suh, S O; Noda, H; Blackwell, M

2001-06-01

Yeast-like endosymbionts (YLSs) of insects often are restricted to specific hosts and are essential to the host's survival. For example, in planthoppers (Homoptera: Delphacidae), endosymbionts function in sterol utilization and nitrogen recycling for the hosts. Our study, designed to investigate evolutionary changes in the YLS lineage involved in the planthopper association, strongly suggests an origin of the YLSs from within the filamentous ascomycetes (Euascomycetes), not the true yeasts (Saccharomycetes), as their morphology might indicate. During divergence of the planthopper YLSs, dramatic changes would have occurred in the insect-fungus interaction and the fungal morphology that have previously been undescribed in filamentous ascomycetes. Phylogenetic trees were based on individual and combined data sets of 2.6 kb of the nuclear small- and large-subunit ribosomal RNA genes for YLSs from three rice planthoppers (Laodelphax striatellus, Nilaparvata lugens, and Sogatella furcifera) compared with 56 other fungi. Parsimony analysis placed the planthopper YLSs within Cordyceps (Euascomycetes: Hypocreales: Clavicipitaceae), a genus of filamentous insects and a few fungal pathogenic ascomycetes. Another YLS species restricted to the aphid Hamiltonaphis styraci (Homoptera: Aphididae) was a sister taxon to the planthopper YLSS: Filamentous insect pathogens (Metarhizium and Beauveria) specific to the same species of insect hosts as the YLSs also formed lineages within the Clavicipitaceae, but these were distinct from the clade comprising YLS species. Trees constrained to include the YLSs in families of the Hypocreales other than the Clavicipitaceae were rejected by the Kishino-Hasegawa test. In addition, the results of this study support a hypothesis of two independent origins of insect-associated YLSs from among filamentous ascomycetes: the planthopper YLSs in the Clavicipitaceae and the YLSs associated with anobiid beetles (Symbiotaphrina species). Several lineages of

Inheritance of resistance to cotton blue disease Herança da resistência do algodoeiro à doença-azul

Directory of Open Access Journals (Sweden)

Osmério Pupim Junior

2008-05-01

Full Text Available The objective of this work was to determine the inheritance of cotton blue disease resistance by cotton plants. Populations derived from the CD 401 and Delta Opal resistant varieties were evaluated, through a greenhouse test with artificial inoculation by viruliferous aphids. Cotton blue disease resistance is conditioned by one dominant gene, both in CD 401 and Delta Opal varieties.O objetivo deste trabalho foi determinar a herança da resistência do algodoeiro à doença-azul. Populações derivadas das variedades resistentes CD 401 e Delta Opal foram avaliadas em casa de vegetação, por meio da inoculação de pulgões virulíferos. A resistência à doença-azul do algodoeiro é condicionada por um gene dominante, tanto em 'DC 401' quanto em 'Delta Opal'.

A Simple and Universal Resistive-Bridge Sensors Interface

Directory of Open Access Journals (Sweden)

Sergey Y. YURISH

2011-02-01

Full Text Available Resistive-bridge sensors are widely used in various sensor systems. There are many sensor signal conditioners from different manufacturers for such sensing elements. However, no one existing on the modern market integrated converter for resistive bridge sensors can work with both: resistive-bridge sensing elements and resistive-to-frequency and -duty-cycle converters’ outputs. A proposed and described in the article universal interface for resistive-bridge sensing elements and bridge-output-to-frequency and/or duty cycle converters based on the designed Universal Sensors and Transducers Interface (USTI integrated. It is based on a simple, cost effective three-point measuring technique and does not require any additional active components. The USTI IC is realized in a standard CMOS technology. The active supply current at operating voltage +4.5 V and clock frequency 20 MHz is not more than 9.5 mA This paper reports experimental results with a strain gauges bridge emulator and differential pressure resistive bridge sensor SX30GD2.

Development of a Selective Medium for the Fungal Pathogen Fusarium graminearum Using Toxoflavin Produced by the Bacterial Pathogen Burkholderia glumae

Directory of Open Access Journals (Sweden)

Boknam Jung

2013-12-01

Full Text Available The ascomycete fungus Fusarium graminearum is a major causal agent for Fusarium head blight in cereals and produces mycotoxins such as trichothecenes and zearalenone. Isolation of the fungal strains from air or cereals can be hampered by various other airborne fungal pathogens and saprophytic fungi. In this study, we developed a selective medium specific to F. graminearum using toxoflavin produced by the bacterial pathogen Burkholderia glumae. F. graminearum was resistant to toxoflavin, while other fungi were sensitive to this toxin. Supplementing toxoflavin into medium enhanced the isolation of F. graminearum from rice grains by suppressing the growth of saprophytic fungal species. In addition, a medium with or without toxoflavin exposed to wheat fields for 1 h had 84% or 25%, respectively, of colonies identified as F. graminearum. This selection medium provides an efficient tool for isolating F. graminearum, and can be adopted by research groups working on genetics and disease forecasting.

Massalongia olechiana (Massalongiaceae, Peltigerales), a new lichen spcies from the Antarctic

DEFF Research Database (Denmark)

Alstrup, Vagn; Søchting, Ulrik

2011-01-01

A new species of lichenized ascomycete, Massalongia olechiana Alstrup et Søchting, sp. nov. (Massalongiaceae) is described from the South Shetland Islands and the Antarctic Peninsula. The species is distinguished by laminal isidia and 5-7-septate ascospores. The relationships with the other species...

Herbicide resistance-endowing ACCase gene mutations in hexaploid wild oat (Avena fatua): insights into resistance evolution in a hexaploid species

Science.gov (United States)

Yu, Q; Ahmad-Hamdani, M S; Han, H; Christoffers, M J; Powles, S B

2013-01-01

Many herbicide-resistant weed species are polyploids, but far too little about the evolution of resistance mutations in polyploids is understood. Hexaploid wild oat (Avena fatua) is a global crop weed and many populations have evolved herbicide resistance. We studied plastidic acetyl-coenzyme A carboxylase (ACCase)-inhibiting herbicide resistance in hexaploid wild oat and revealed that resistant individuals can express one, two or three different plastidic ACCase gene resistance mutations (Ile-1781-Leu, Asp-2078-Gly and Cys-2088-Arg). Using ACCase resistance mutations as molecular markers, combined with genetic, molecular and biochemical approaches, we found in individual resistant wild-oat plants that (1) up to three unlinked ACCase gene loci assort independently following Mendelian laws for disomic inheritance, (2) all three of these homoeologous ACCase genes were transcribed, with each able to carry its own mutation and (3) in a hexaploid background, each individual ACCase resistance mutation confers relatively low-level herbicide resistance, in contrast to high-level resistance conferred by the same mutations in unrelated diploid weed species of the Poaceae (grass) family. Low resistance conferred by individual ACCase resistance mutations is likely due to a dilution effect by susceptible ACCase expressed by homoeologs in hexaploid wild oat and/or differential expression of homoeologous ACCase gene copies. Thus, polyploidy in hexaploid wild oat may slow resistance evolution. Evidence of coexisting non-target-site resistance mechanisms among wild-oat populations was also revealed. In all, these results demonstrate that herbicide resistance and its evolution can be more complex in hexaploid wild oat than in unrelated diploid grass weeds. Our data provide a starting point for the daunting task of understanding resistance evolution in polyploids. PMID:23047200

Nectar sugars and bird visitation define a floral niche for basidiomycetous yeast on the Canary Islands.

Science.gov (United States)

Mittelbach, Moritz; Yurkov, Andrey M; Nocentini, Daniele; Nepi, Massimo; Weigend, Maximilian; Begerow, Dominik

2015-02-01

Studies on the diversity of yeasts in floral nectar were first carried out in the late 19th century. A narrow group of fermenting, osmophilous ascomycetes were regarded as exclusive specialists able to populate this unique and species poor environment. More recently, it became apparent that microorganisms might play an important role in the process of plant pollination. Despite the importance of these nectar dwelling yeasts, knowledge of the factors that drive their diversity and species composition is scarce. In this study, we linked the frequencies of yeast species in floral nectars from various host plants on the Canary Islands to nectar traits and flower visitors. We estimated the structuring impact of pollination syndromes (nectar volume, sugar concentration and sugar composition) on yeast diversity.The observed total yeast diversity was consistent with former studies, however, the present survey yielded additional basidiomycetous yeasts in unexpectedly high numbers. Our results show these basidiomycetes are significantly associated with ornithophilous flowers. Specialized ascomycetes inhabit sucrose-dominant nectars, but are surprisingly rare in nectar dominated by monosaccharides. There are two conclusions from this study: (i) a shift of floral visitors towards ornithophily alters the likelihood of yeast inoculation in flowers, and (ii) low concentrated hexose-dominant nectar promotes colonization of flowers by basidiomycetes. In the studied floral system, basidiomycete yeasts are acknowledged as regular members of nectar. This challenges the current understanding that nectar is an ecological niche solely occupied by ascomycetous yeasts.

A case illustration of resistance from a gestalt-experiential perspective.

Science.gov (United States)

Engle, David; Holiman, Marjorie

2002-02-01

The case of Victoria illustrates psychotherapy with a woman faced with a difficult and unexpected divorce. The authors present a summary of typical struggles faced by Victoria through three phases of therapy. The therapy focused initially on coping with the divorce, then moved to work on her career dissatisfaction, and finally to her efforts to develop a new relationship. The case presentation illustrates resistance as it manifested itself in both a behavioral manner and as in-session resistance to awareness of internal states. The behavioral mode of resistance is manifested by her inability to follow through on decisions made in therapy sessions and by her interruptions of ongoing therapy. A transcript of a typical in-session exchange illustrates the resistance to awareness. The authors also describe interventions intended to work with the resistance. Copyright 2002 John Wiley & Sons, Inc.

The Stigma Resistance Scale: A multi-sample validation of a new instrument to assess mental illness stigma resistance.

Science.gov (United States)

Firmin, Ruth L; Lysaker, Paul H; McGrew, John H; Minor, Kyle S; Luther, Lauren; Salyers, Michelle P

2017-12-01

Although associated with key recovery outcomes, stigma resistance remains under-studied largely due to limitations of existing measures. This study developed and validated a new measure of stigma resistance. Preliminary items, derived from qualitative interviews of people with lived experience, were pilot tested online with people self-reporting a mental illness diagnosis (n = 489). Best performing items were selected, and the refined measure was administered to an independent sample of people with mental illness at two state mental health consumer recovery conferences (n = 202). Confirmatory factor analyses (CFA) guided by theory were used to test item fit, correlations between the refined stigma resistance measure and theoretically relevant measures were examined for validity, and test-retest correlations of a subsample were examined for stability. CFA demonstrated strong fit for a 5-factor model. The final 20-item measure demonstrated good internal consistency for each of the 5 subscales, adequate test-retest reliability at 3 weeks, and strong construct validity (i.e., positive associations with quality of life, recovery, and self-efficacy, and negative associations with overall symptoms, defeatist beliefs, and self-stigma). The new measure offers a more reliable and nuanced assessment of stigma resistance. It may afford greater personalization of interventions targeting stigma resistance. Copyright © 2017 Elsevier B.V. All rights reserved.

A critical role for Arabidopsis MILDEW RESISTANCE LOCUS O2 in systemic acquired resistance.

Science.gov (United States)

Gruner, Katrin; Zeier, Tatyana; Aretz, Christina; Zeier, Jürgen

2018-04-16

Members of the MILDEW RESISTANCE LOCUS O (MLO) gene family confer susceptibility to powdery mildews in different plant species, and their existence therefore seems to be disadvantageous for the plant. We recognized that expression of the Arabidopsis MLO2 gene is induced after inoculation with the bacterial pathogen Pseudomonas syringae, promoted by salicylic acid (SA) signaling, and systemically enhanced in the foliage of plants exhibiting systemic acquired resistance (SAR). Importantly, distinct mlo2 mutant lines were unable to systemically increase resistance to bacterial infection after inoculation with P. syringae, indicating that the function of MLO2 is necessary for biologically-induced SAR in Arabidopsis. Our data also suggest that the close homolog MLO6 has a supportive but less critical role in SAR. In contrast to SAR, basal resistance to bacterial infection was not affected in mlo2. Remarkably, SAR-defective mlo2 mutants were still competent in systemically increasing the levels of the SAR-activating metabolites pipecolic acid (Pip) and SA after inoculation, and to enhance SAR-related gene expression in distal plant parts. Furthermore, although MLO2 was not required for SA- or Pip-inducible defense gene expression, it was essential for the proper induction of disease resistance by both SAR signals. We conclude that MLO2 acts as a critical downstream component in the execution of SAR to bacterial infection, being required for the translation of elevated defense responses into disease resistance. Moreover, our data suggest a function for MLO2 in the activation of plant defense priming during a P. syringae challenge. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Early detection of airborne inoculum of Magnaporthe oryzae in turfgrass fields using a quantitative LAMP assay

Science.gov (United States)

Gray leaf spot (GLS) is a destructive disease of perennial ryegrass caused by a host specific pathotype of the ascomycete Magnaporthe oryzae. Early diagnosis is crucial for effective disease management and the implementation of Integrated Pest Management practices. However, a rapid diagnostic protoc...

A study of dynamic resistance during small scale resistance spot welding of thin Ni sheets

International Nuclear Information System (INIS)

Tan, W; Zhou, Y; Kerr, H W; Lawson, S

2004-01-01

The dynamic resistance has been investigated during small scale resistance spot welding (SSRSW) of Ni sheets. Electrical measurements have been correlated with scanning electron microscope images of joint development. The results show that the dynamic resistance curve can be divided into the following stages based on physical change in the workpieces: asperity heating, surface breakdown, asperity softening, partial surface melting, nugget growth and expulsion. These results are also compared and contrasted with dynamic resistance behaviour in large scale RSW

Radiation resistance in a melphalan-resistant subline of a rat mammary carcinoma

International Nuclear Information System (INIS)

Lehnert, S.; Vestergaard, J.; Batist, G.; Aloui-Jamali, M.A.

1994-01-01

A subline of a rat mammary carcinoma (MATB 13762), selected for resistance to melphalan, is cross-resistant to other alkylating drugs, to unrelated drugs and to ionizing radiation. The difference in radioresponse between the sensitive wild-type cell line and the melphalan- and radiation-resistant line (MLN r ) is related to the size of the α component in the linear-quadratic model. Reduction of dose rate does not affect the response of MLN r cells but does increase survival for wild-type cells. MLN r cells have elevated levels of reduced glutathione (GSH) and overexpress redox enzymes glutathione-S-transferase and glutathione peroxidase. Modest depletion of GSH (to 50% of control) radiosensitizes MLN r cells but not wild-type cells. On the basis of the results of an excitation assay, growth delay and tumor control experiments, MATB MLN r tumors are also more radioresistant than wild-type cells when irradiated in situ. However, wild-type cells irradiated shortly after excision of the tumor are much more radioresistant than the same cells irradiated 24 h after excision or maintained in culture, and their response resembles that of MLN r cells irradiated under the same conditions. These results suggest that, in spite of some similarity between the in vivo and in vitro observations, intrinsic radioresistance is not the most important factor influencing the response of MLN r cells in vivo. 22 refs., 7 figs., 4 tabs

Impact of ertapenem on antimicrobial resistance in a sentinel group of Gram-negative bacilli: a 6 year antimicrobial resistance surveillance study.

Science.gov (United States)

Rodriguez-Osorio, Carlos A; Sanchez-Martinez, Cesar O; Araujo-Melendez, Javier; Criollo, Elia; Macias-Hernandez, Alejandro E; Ponce-de-Leon, Alfredo; Ponce-de-Leon, Sergio; Sifuentes-Osornio, Jose

2015-03-01

To determine the association between ertapenem and resistance of Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii-calcoaceticus complex to different antimicrobials while adjusting for relevant hospital factors. This was a retrospective time-series study conducted at a tertiary care centre from September 2002 to August 2008. The specific impact of ertapenem on the resistance of these Gram-negative bacilli (GNB) was assessed by multiple linear regression analysis, adjusting for the average length of stay, rate of hospital-acquired infections and use of 10 other antimicrobials, including type 2 carbapenems. Unadjusted analyses revealed significant increases over the duration of the study in the number of GNB resistant to meropenem/imipenem among 1000 isolates each of E. coli (0.46 ± 0.22, P  0.05) with changes in resistance for any pathogen/antimicrobial combination. After controlling for confounders, ertapenem was not associated with changes in resistance in a group of sentinel GNB, although significant variations in resistance to different antimicrobials were observed in the unadjusted analyses. These results emphasize the importance of implementation of local resistance surveillance platforms and stewardship programmes to combat the global emergence and spread of antimicrobial resistance. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Proliferation resistance design of a plutonium cycle (Proliferation Resistance Engineering Program: PREP)

Energy Technology Data Exchange (ETDEWEB)

Sorenson, R.J.; Roberts, F.P.; Clark, R.G.

1979-01-19

This document describes the proliferation resistance engineering concepts developed to counter the threat of proliferation of nuclear weapons in an International Fuel Service Center (IFSC). The basic elements of an International Fuel Service Center are described. Possible methods for resisting proliferation such as processing alternatives, close-coupling of facilities, process equipment layout, maintenance philosophy, process control, and process monitoring are discussed. Political and institutional issues in providing proliferation resistance for an International Fuel Service Center are analyzed. The conclusions drawn are (1) use-denial can provide time for international response in the event of a host nation takeover. Passive use-denial is more acceptable than active use-denial, and acceptability of active-denial concepts is highly dependent on sovereignty, energy dependence and economic considerations; (2) multinational presence can enhance proliferation resistance; and (3) use-denial must be nonprejudicial with balanced interests for governments and/or private corporations being served. Comparisons between an IFSC as a national facility, an IFSC with minimum multinational effect, and an IFSC with maximum multinational effect show incremental design costs to be less than 2% of total cost of the baseline non-PRE concept facility. The total equipment acquisition cost increment is estimated to be less than 2% of total baseline facility costs. Personnel costs are estimated to increase by less than 10% due to maximum international presence. 46 figures, 9 tables.

Proliferation resistance design of a plutonium cycle (Proliferation Resistance Engineering Program: PREP)

International Nuclear Information System (INIS)

Sorenson, R.J.; Roberts, F.P.; Clark, R.G.

1979-01-01

This document describes the proliferation resistance engineering concepts developed to counter the threat of proliferation of nuclear weapons in an International Fuel Service Center (IFSC). The basic elements of an International Fuel Service Center are described. Possible methods for resisting proliferation such as processing alternatives, close-coupling of facilities, process equipment layout, maintenance philosophy, process control, and process monitoring are discussed. Political and institutional issues in providing proliferation resistance for an International Fuel Service Center are analyzed. The conclusions drawn are (1) use-denial can provide time for international response in the event of a host nation takeover. Passive use-denial is more acceptable than active use-denial, and acceptability of active-denial concepts is highly dependent on sovereignty, energy dependence and economic considerations; (2) multinational presence can enhance proliferation resistance; and (3) use-denial must be nonprejudicial with balanced interests for governments and/or private corporations being served. Comparisons between an IFSC as a national facility, an IFSC with minimum multinational effect, and an IFSC with maximum multinational effect show incremental design costs to be less than 2% of total cost of the baseline non-PRE concept facility. The total equipment acquisition cost increment is estimated to be less than 2% of total baseline facility costs. Personnel costs are estimated to increase by less than 10% due to maximum international presence. 46 figures, 9 tables

The yeast flora of some decaying mushrooms on trunks of living trees

OpenAIRE

Middelhoven, W.J.

2004-01-01

Several ascomycetous and basidiomycetous yeasts were isolated from rotten mushrooms on the trunks of beech and tamarisk trees. One strain, identified as the novel species Cryptococcus allantoinivorans, assimilated allantoin as the sole carbon source. Phylogenetically it belongs to the C. laurentii complex, Papiliotrema bandonii being the closest relative. Some ascomycetous strains could not be distinguished from Pichia guillermondii, but deviated considerably in rDNA sequences. In addition to...

A synopsis of the saddle fungi (Helvella: Ascomycota) in Europe – species delimitation, taxonomy and typification

NARCIS (Netherlands)

Skrede, I.; Carlsen, T.; Schumacher, T.

2017-01-01

Helvella is a widespread, speciose genus of large apothecial ascomycetes (Pezizomycete: Pezizales) that are found in terrestrial biomes of the Northern and Southern Hemispheres. This study represents a beginning on assessing species limits and applying correct names for Helvella species based on

A weed resistance management game: a teaching tool.

Science.gov (United States)

Frisvold, George B

2018-04-15

This article provides instructions and materials to moderate an interactive resistance management game. The game is designed to generate discussion about the challenges and possibilities of coordinating resistance management activities among groups of farmers. The game has been successfully applied in classroom settings, extension workshops, and at professional weed science meetings. Research has found farmers often perceive the success of their own resistance management may be thwarted if their neighbors are not adequately managing resistance as well. This can lead to negative 'tragedy of the commons' outcomes. In past applications of the game exercise, participants have often responded in ways consistent with similar studies in experimental and behavioral economics. This includes dividing benefits evenly (even though this is not a requirement of the game) or treating one-time transactions as potentially repeated exchanges. Player behavior may also be greatly influenced by their attitudes toward monetary risks. The game allows participants to explore ways to overcome the tragedy of the commons and illustrates the roles of information sharing and economic incentives in finding solutions. It also allows participants to experiment with bottom-up voluntary approaches toward resistance management as an alternative to top-down regulatory approaches. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Inheritance of Cry1F resistance, cross-resistance and frequency of resistant alleles in Spodoptera frugiperda (Lepidoptera: Noctuidae).

Science.gov (United States)

Vélez, A M; Spencer, T A; Alves, A P; Moellenbeck, D; Meagher, R L; Chirakkal, H; Siegfried, B D

2013-12-01

Transgenic maize, Zea maize L., expressing the Cry1F protein from Bacillus thuringiensis has been registered for Spodoptera frugiperda (J. E. Smith) control since 2003. Unexpected damage to Cry1F maize was reported in 2006 in Puerto Rico and Cry1F resistance in S. frugiperda was documented. The inheritance of Cry1F resistance was characterized in a S. frugiperda resistant strain originating from Puerto Rico, which displayed >289-fold resistance to purified Cry1F. Concentration-response bioassays of reciprocal crosses of resistant and susceptible parental populations indicated that resistance is recessive and autosomal. Bioassays of the backcross of the F1 generation crossed with the resistant parental strain suggest that a single locus is responsible for resistance. In addition, cross-resistance to Cry1Aa, Cry1Ab, Cry1Ac, Cry1Ba, Cry2Aa and Vip3Aa was assessed in the Cry1F-resistant strain. There was no significant cross-resistance to Cry1Aa, Cry1Ba and Cry2Aa, although only limited effects were observed in the susceptible strain. Vip3Aa was highly effective against susceptible and resistant insects indicating no cross-resistance with Cry1F. In contrast, low levels of cross-resistance were observed for both Cry1Ab and Cry1Ac. Because the resistance is recessive and conferred by a single locus, an F1 screening assay was used to measure the frequency of Cry1F-resistant alleles from populations of Florida and Texas in 2010 and 2011. A total frequency of resistant alleles of 0.13 and 0.02 was found for Florida and Texas populations, respectively, indicating resistant alleles could be found in US populations, although there have been no reports of reduced efficacy of Cry1F-expressing plants.

Schizosaccharomyces pombe, the Principal Subject of Fission Yeast Genetics

DEFF Research Database (Denmark)

Egel, Richard

2013-01-01

Schizosaccharomyces pombe is a primitive ascomycetous fungus, also known as fission yeast. It has been extensively used in general and molecular genetics, and its genome is fully sequenced. It is considered a very useful model organism for experimental research on fundamental properties of eukary......Schizosaccharomyces pombe is a primitive ascomycetous fungus, also known as fission yeast. It has been extensively used in general and molecular genetics, and its genome is fully sequenced. It is considered a very useful model organism for experimental research on fundamental properties...

Outwitting the series resistance in scanning spreading resistance microscopy

International Nuclear Information System (INIS)

Schulze, A.; Cao, R.; Eyben, P.; Hantschel, T.; Vandervorst, W.

2016-01-01

The performance of nanoelectronics devices critically depends on the distribution of active dopants inside these structures. For this reason, dopant profiling has been defined as one of the major metrology challenges by the international technology roadmap of semiconductors. Scanning spreading resistance microscopy (SSRM) has evolved as one of the most viable approaches over the last decade due to its excellent spatial resolution, sensitivity and quantification accuracy. However, in case of advanced device architectures like fins and nanowires a proper measurement of the spreading resistance is often hampered by the increasing impact of parasitic series resistances (e.g. bulk series resistance) arising from the confined nature of the aforementioned structures. In order to overcome this limitation we report in this paper the development and implementation of a novel SSRM mode (fast Fourier transform-SSRM: FFT-SSRM) which essentially decouples the spreading resistance from parasitic series resistance components. We show that this can be achieved by a force modulation (leading to a modulated spreading resistance signal) in combination with a lock-in deconvolution concept. In this paper we first introduce the principle of operation of the technique. We discuss in detail the underlying physical mechanisms as well as the technical implementation on a state-of-the-art atomic force microscope (AFM). We demonstrate the performance of FFT-SSRM and its ability to remove substantial series resistance components in practice. Eventually, the possibility of decoupling the spreading resistance from the intrinsic probe resistance will be demonstrated and discussed. - Highlights: • A novel electrical AFM mode for carrier profiling in confined volumes is presented. • Thereby the force and hence the contact area between AFM probe and sample is modulated. • Information on the spreading resistance is derived using a lock-in approach. • Bulk series resistance components are

Bacterial resistance and impetigo treatment trends: a review.

Science.gov (United States)

Bangert, Scott; Levy, Moise; Hebert, Adelaide A

2012-01-01

Impetigo is a common cutaneous infection that is especially prevalent in children. The prevalence of colonization and infection with resistant strains is continually increasing, forcing clinicians to reevaluate treatment strategies. Newer topical agents are effective in treating infections with resistant strains and may help minimize resistance and adverse effects from systemic agents. Use of topical disinfectants to decrease colonization is an important adjunctive measure. Physicians should be aware of local resistance patterns in impetigo to help guide therapy. © 2012 Wiley Periodicals, Inc.

A new player in race-specific resistance

KAUST Repository

Keller, Beat

2018-04-04

Race-specific resistance genes represent essential genetic sources in crop breeding. Map-based cloning of the wheat Stb6 gene against Zymoseptoria tritici identified a wall-associated receptor kinase-like protein as a novel player in race-specific disease resistance.

Resistance to Disruption in a Classroom Setting

Science.gov (United States)

Parry-Cruwys, Diana E.; Neal, Carrie M.; Ahearn, William H.; Wheeler, Emily E.; Premchander, Raseeka; Loeb, Melissa B.; Dube, William V.

2011-01-01

Substantial experimental evidence indicates that behavior reinforced on a denser schedule is more resistant to disruption than is behavior reinforced on a thinner schedule. The present experiment studied resistance to disruption in a natural educational environment. Responding during familiar activities was reinforced on a multiple…

Antimicrobial resistance in the 21st century: a multifaceted challenge.

Science.gov (United States)

Nolte, O

2014-04-01

Antimicrobial resistance, the ability of (pathogenic) bacteria to withstand the action of antibiotic drugs, has recently been rated of having an impact on humans similar to that of global climate change. Indeed, during the last years medicine has faced the development of highly resistant bacterial strains, which were, as a consequence of worldwide travel activity, dispersed all over the globe. This is even more astonishing if taking into account that antibiotics were introduced into human medicine not even hundred years ago. Resistance covers different principle aspects, natural resistance, acquired resistance and clinical resistance. In the modern microbiology laboratory, antimicrobial resistance is determined by measuring the susceptibility of micro-organisms in vitro in the presence of antimicrobials. However, since the efficacy of an antibiotic depends on its pharmacokinetic and pharmacodynamics properties, breakpoints are provided to translate minimal inhibitory concentration to categorical efficacy (i.e. susceptible or resistant). Resistance in one microorganism against one particular drug may drive treatment decisions of clinicians, thereby fostering selection pressure to resistance development against another antibiotic. Thereby, bacteria may acquire more and more resistance traits, ending up with multi-resistance. To this end, antimicrobial resistance becomes a public health concern, not only in terms of limited treatment options but also due to its economic burden. The current paper provides a summary of the main topics associated with antimicrobial resistance as an introduction to this special issue.

A Comparative Study of the Cell Wall Structure of Basidiomycetous and Related Yeasts

NARCIS (Netherlands)

Kreger-van Rij, N.J.W.; Veenhuis, M.

1971-01-01

The wall of basidiomycetous and related yeasts showed a lamellar structure in sections of both budding cells and hyphae fixed with potassium permanganate. The yeasts also had a typical way of bud formation and septation. These features differ from those recorded for ascomycetous yeasts. In the

A Non-canonical Melanin Biosynthesis Pathway Protects Aspergillus terreus Conidia from Environmental Stress.

Science.gov (United States)

Geib, Elena; Gressler, Markus; Viediernikova, Iuliia; Hillmann, Falk; Jacobsen, Ilse D; Nietzsche, Sandor; Hertweck, Christian; Brock, Matthias

2016-05-19

Melanins are ubiquitous pigments found in all kingdoms of life. Most organisms use them for protection from environmental stress, although some fungi employ melanins as virulence determinants. The human pathogenic fungus Aspergillus fumigatus and related Ascomycetes produce dihydroxynaphthalene- (DHN) melanin in their spores, the conidia, and use it to inhibit phagolysosome acidification. However, biosynthetic origin of melanin in a related fungus, Aspergillus terreus, has remained a mystery because A. terreus lacks genes for synthesis of DHN-melanin. Here we identify genes coding for an unusual NRPS-like enzyme (MelA) and a tyrosinase (TyrP) that A. terreus expressed under conidiation conditions. We demonstrate that MelA produces aspulvinone E, which is activated for polymerization by TyrP. Functional studies reveal that this new pigment, Asp-melanin, confers resistance against UV light and hampers phagocytosis by soil amoeba. Unexpectedly, Asp-melanin does not inhibit acidification of phagolysosomes, thus likely contributing specifically to survival of A. terreus conidia in acidic environments. Copyright © 2016 Elsevier Ltd. All rights reserved.

Resistance to Linezolid

DEFF Research Database (Denmark)

Vester, Birte; Ntokou, Eleni

2017-01-01

Linezolid is an antimicrobial agent that binds to the bacterial ribosome and thereby inhibits protein synthesis. Soon after its release as a clinical drug, it became clear that bacteria could become resistant to linezolid. The resistance mechanisms are mainly causing alteration of the drug target...... site, but probably efflux might also play a role. The resistance is still rare in surveillance studies, but outbreaks of resistant clones from hospitals have been observed. So far the main mechanisms of resistance are occurrence of mutations in ribosomal genes or obtaining plasmids with a gene coding...... for a methyltransferase providing resistance. The most obvious way to avoid resistance may be development of derivatives of linezolid overcoming the known resistance mechanisms....

Resistance switch employing a simple metal nanogap junction

International Nuclear Information System (INIS)

Naitoh, Yasuhisa; Horikawa, Masayo; Abe, Hidekazu; Shimizu, Tetsuo

2006-01-01

In recent years, several researchers have reported the occurrence of reversible resistance switching effects in simple metal nanogap junctions. A large negative resistance is observed in the I-V characteristics of such a junction when high-bias voltages are applied. This phenomenon is characteristic behaviour on the nanometre scale; it only occurs for gap widths slightly under 13 nm. Furthermore, such a junction exhibits a non-volatile resistance hysteresis when the bias voltage is reduced very rapidly from a high level to around 0 V, and when the bias voltage is reduced slowly. This non-volatile resistance change occurs as a result of changes in the gap width between the metal electrodes, brought about by the applied bias voltage

[Antibiotic resistance: A global crisis].

Science.gov (United States)

Alós, Juan-Ignacio

2015-12-01

The introduction of antibiotics into clinical practice represented one of the most important interventions for the control of infectious diseases. Antibiotics have saved millions of lives and have also brought a revolution in medicine. However, an increasing threat has deteriorated the effectiveness of these drugs, that of bacterial resistance to antibiotics, which is defined here as the ability of bacteria to survive in antibiotic concentrations that inhibit/kill others of the same species. In this review some recent and important examples of resistance in pathogens of concern for mankind are mentioned. It is explained, according to present knowledge, the process that led to the current situation in a short time, evolutionarily speaking. It begins with the resistance genes, continues with clones and genetic elements involved in the maintenance and dissemination, and ends with other factors that contribute to its spread. Possible responses to the problem are also reviewed, with special reference to the development of new antibiotics. Copyright © 2014 Elsevier España, S.L.U. y Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

Resist materials for proton beam writing: A review

Energy Technology Data Exchange (ETDEWEB)

Kan, J.A. van, E-mail: phyjavk@nus.edu.sg [Centre for Ion Beam Applications, Physics Department, 2 Science Drive 3, National University of Singapore, 117542 Singapore (Singapore); Malar, P. [Research Institute, SRM University, Kattankulathur, Chennai 603203 (India); Wang, Y.H. [Centre for Ion Beam Applications, Physics Department, 2 Science Drive 3, National University of Singapore, 117542 Singapore (Singapore)

2014-08-15

Highlights: • PBW can now achieve 19 nm details in HSQ and 65 nm in PMMA. • A complete table of resist materials for PBW has been presented, including minimum feature size, achievable aspect ratio, suitability for electroplating and where available contrast of the resist. • PBW fabricated molds can now be used for single DNA molecule detection, single DNA manipulation and large scale Genome mapping. - Abstract: Proton beam writing (PBW) is a lithographic technique that has been developed since the mid 1990s, initially in Singapore followed by several groups around the world. MeV protons while penetrating materials will maintain a practically straight path. During the continued slowing down of a proton in material it will mainly interact with substrate electrons and transfer a small amount of energy to each electron, the induced secondary electrons will modify the molecular structure of resist within a few nanometers around the proton track. The recent demonstration of high aspect ratio sub 20 nm lithography in HSQ shows the potential of PBW. To explore the full capabilities of PBW, the understanding of the interaction of fast protons with different resist materials is important. Here we give an update of the growing number of resist materials that have been evaluated for PBW. In particular we evaluate the exposure and development strategies for the most promising resist materials like PMMA, HSQ, SU-8 and AR-P and compare their characteristics with respect to properties such as contrast and sensitivity. Besides an updated literature survey we also present new findings on AR-P and PMGI resists. Since PBW is a direct write technology it is important to look for fast ways to replicate micro and nanostructures. In this respect we will discuss the suitability and performance of several resists for Ni electroplating for mold fabrication in nano imprint technologies. We will summarize with an overview of proton resist characteristics like sensitivity, contrast

Resist materials for proton beam writing: A review

International Nuclear Information System (INIS)

Kan, J.A. van; Malar, P.; Wang, Y.H.

2014-01-01

Highlights: • PBW can now achieve 19 nm details in HSQ and 65 nm in PMMA. • A complete table of resist materials for PBW has been presented, including minimum feature size, achievable aspect ratio, suitability for electroplating and where available contrast of the resist. • PBW fabricated molds can now be used for single DNA molecule detection, single DNA manipulation and large scale Genome mapping. - Abstract: Proton beam writing (PBW) is a lithographic technique that has been developed since the mid 1990s, initially in Singapore followed by several groups around the world. MeV protons while penetrating materials will maintain a practically straight path. During the continued slowing down of a proton in material it will mainly interact with substrate electrons and transfer a small amount of energy to each electron, the induced secondary electrons will modify the molecular structure of resist within a few nanometers around the proton track. The recent demonstration of high aspect ratio sub 20 nm lithography in HSQ shows the potential of PBW. To explore the full capabilities of PBW, the understanding of the interaction of fast protons with different resist materials is important. Here we give an update of the growing number of resist materials that have been evaluated for PBW. In particular we evaluate the exposure and development strategies for the most promising resist materials like PMMA, HSQ, SU-8 and AR-P and compare their characteristics with respect to properties such as contrast and sensitivity. Besides an updated literature survey we also present new findings on AR-P and PMGI resists. Since PBW is a direct write technology it is important to look for fast ways to replicate micro and nanostructures. In this respect we will discuss the suitability and performance of several resists for Ni electroplating for mold fabrication in nano imprint technologies. We will summarize with an overview of proton resist characteristics like sensitivity, contrast

Corrosion-Resistant High-Entropy Alloys: A Review

Directory of Open Access Journals (Sweden)

Yunzhu Shi

2017-02-01

Full Text Available Corrosion destroys more than three percent of the world’s gross domestic product. Therefore, the design of highly corrosion-resistant materials is urgently needed. By breaking the classical alloy-design philosophy, high-entropy alloys (HEAs possess unique microstructures, which are solid solutions with random arrangements of multiple elements. The particular locally-disordered chemical environment is expected to lead to unique corrosion-resistant properties. In this review, the studies of the corrosion-resistant HEAs during the last decade are summarized. The corrosion-resistant properties of HEAs in various aqueous environments and the corrosion behavior of HEA coatings are presented. The effects of environments, alloying elements, and processing methods on the corrosion resistance are analyzed in detail. Furthermore, the possible directions of future work regarding the corrosion behavior of HEAs are suggested.

Antibiotic-resistant bacteria: a challenge for the food industry.

Science.gov (United States)

Capita, Rosa; Alonso-Calleja, Carlos

2013-01-01

Antibiotic-resistant bacteria were first described in the 1940s, but whereas new antibiotics were being discovered at a steady rate, the consequences of this phenomenon were slow to be appreciated. At present, the paucity of new antimicrobials coming into the market has led to the problem of antibiotic resistance fast escalating into a global health crisis. Although the selective pressure exerted by the use of antibiotics (particularly overuse or misuse) has been deemed the major factor in the emergence of bacterial resistance to these antimicrobials, concerns about the role of the food industry have been growing in recent years and have been raised at both national and international levels. The selective pressure exerted by the use of antibiotics (primary production) and biocides (e.g., disinfectants, food and feed preservatives, or decontaminants) is the main driving force behind the selection and spread of antimicrobial resistance throughout the food chain. Genetically modified (GM) crops with antibiotic resistance marker genes, microorganisms added intentionally to the food chain (probiotic or technological) with potentially transferable antimicrobial resistance genes, and food processing technologies used at sub-lethal doses (e.g., alternative non-thermal treatments) are also issues for concern. This paper presents the main trends in antibiotic resistance and antibiotic development in recent decades, as well as their economic and health consequences, current knowledge concerning the generation, dissemination, and mechanisms of antibacterial resistance, progress to date on the possible routes for emergence of resistance throughout the food chain and the role of foods as a vehicle for antibiotic-resistant bacteria. The main approaches to prevention and control of the development, selection, and spread of antibacterial resistance in the food industry are also addressed.

Measurement of Dynamic Resistance in Resistance Spot Welding

DEFF Research Database (Denmark)

Wu, Pei; Zhang, Wenqi; Bay, Niels

Through years, the dynamic resistance across the electrodes has been used for weld quality estimation and contact resistance measurement. However, the previous methods of determining the dynamic resistance were mostly based on measuring the voltage and current on the secondary side of the transfo......Through years, the dynamic resistance across the electrodes has been used for weld quality estimation and contact resistance measurement. However, the previous methods of determining the dynamic resistance were mostly based on measuring the voltage and current on the secondary side...... of the transformer in resistance welding machines, implying defects from induction noise and interference with the leads connected to the electrodes for measuring the voltage. In this study, the dynamic resistance is determined by measuring the voltage on the primary side and the current on the secondary side...

Draft genome sequence of the yeast Starmerella bacillaris (syn., Candida zemplinina) FRI751 isolated from fermenting must of dried Raboso grapes

DEFF Research Database (Denmark)

Lemos Junior, Wilson Jose Fernandes; Treu, Laura; da Silva Duarte, Vinicius

2017-01-01

Starmerella bacillaris is an ascomycetous yeast commonly present in enological environments. Here, we report the first draft genome sequence of S. bacillaris FRI751, which will facilitate the study of the characteristics of this interesting enological yeast.......Starmerella bacillaris is an ascomycetous yeast commonly present in enological environments. Here, we report the first draft genome sequence of S. bacillaris FRI751, which will facilitate the study of the characteristics of this interesting enological yeast....

Development of a rapid multiplex SSR genotyping method to study populations of the fun-gal plant pathogen Zymoseptoria tritici

NARCIS (Netherlands)

Gautier, A.; Marcel, T.C.; Confais, J.; Crane, C.; Kema, G.H.J.; Suffert, F.; Walker, A.S.

2014-01-01

Background Zymoseptoria tritici is a hemibiotrophic ascomycete fungus causing leaf blotch of wheat that often decreases yield severely. Populations of the fungus are known to be highly diverse and poorly differentiated from each other. However, a genotyping tool is needed to address further

[Naturally occurring oseltamivir resistance in influenza A.

DEFF Research Database (Denmark)

Madsen, Laura; Nielsen, Alex; Lundgren, Jens

2010-01-01

in the development of resistance. The best prevention strategy remains vaccination of the general population to avoid immunity. Future antiviral treatment calls for knowledge about resistance to existing types of influenza and the availability of all three types of antiviral medication. Udgivelsesdato: 2010-Aug......During the last two influenza seasons, one of the predominant influenza A types (H1N1) has developed complete resistance to oseltamivir, the primary treatment option. The virus does, however, remain sensitive to zanamavir and amantadine. There is no unequivocal explanation for this slide...

[Naturally occurring oseltamivir resistance in influenza A.

DEFF Research Database (Denmark)

Madsen, Laura; Nielsen, Alex; Lundgren, Jens

2010-01-01

During the last two influenza seasons, one of the predominant influenza A types (H1N1) has developed complete resistance to oseltamivir, the primary treatment option. The virus does, however, remain sensitive to zanamavir and amantadine. There is no unequivocal explanation for this slide...... in the development of resistance. The best prevention strategy remains vaccination of the general population to avoid immunity. Future antiviral treatment calls for knowledge about resistance to existing types of influenza and the availability of all three types of antiviral medication. Udgivelsesdato: 2010-Aug...

Antibiotic resistance

Directory of Open Access Journals (Sweden)

Marianne Frieri

2017-07-01

Full Text Available Summary: Antimicrobial resistance in bacterial pathogens is a challenge that is associated with high morbidity and mortality. Multidrug resistance patterns in Gram-positive and -negative bacteria are difficult to treat and may even be untreatable with conventional antibiotics. There is currently a shortage of effective therapies, lack of successful prevention measures, and only a few new antibiotics, which require development of novel treatment options and alternative antimicrobial therapies. Biofilms are involved in multidrug resistance and can present challenges for infection control. Virulence, Staphylococcus aureus, Clostridium difficile infection, vancomycin-resistant enterococci, and control in the Emergency Department are also discussed. Keywords: Antibiotic resistance, Biofilms, Infections, Public health, Emergency Department

Resistant plasmid profile analysis of multidrug resistant Escherichia ...

African Journals Online (AJOL)

Background: Multi-drug resistant Escherichia coli has become a major threat and cause of many urinary tract infections (UTIs) in Abeokuta, Nigeria. Objectives: This study was carried out to determine the resistant plasmids of multidrug resistant Escherichia coli isolated from (Urinary tract infections)UTIs in Abeokuta.

Phi Class of Glutathione S-transferase Gene Superfamily Widely Exists in Nonplant Taxonomic Groups.

Science.gov (United States)

Munyampundu, Jean-Pierre; Xu, You-Ping; Cai, Xin-Zhong

2016-01-01

Glutathione S-transferases (GSTs) constitute a superfamily of enzymes involved in detoxification of noxious compounds and protection against oxidative damage. GST class Phi (GSTF), one of the important classes of plant GSTs, has long been considered as plant specific but was recently found in basidiomycete fungi. However, the range of nonplant taxonomic groups containing GSTFs remains unknown. In this study, the distribution and phylogenetic relationships of nonplant GSTFs were investigated. We identified GSTFs in ascomycete fungi, myxobacteria, and protists Naegleria gruberi and Aureococcus anophagefferens. GSTF occurrence in these bacteria and protists correlated with their genome sizes and habitats. While this link was missing across ascomycetes, the distribution and abundance of GSTFs among ascomycete genomes could be associated with their lifestyles to some extent. Sequence comparison, gene structure, and phylogenetic analyses indicated divergence among nonplant GSTFs, suggesting polyphyletic origins during evolution. Furthermore, in silico prediction of functional partners suggested functional diversification among nonplant GSTFs.

Low-level quinolone-resistance in multi-drug resistant typhoid

Energy Technology Data Exchange (ETDEWEB)

Mirza, S H; Khan, M A [Armed Forces Inst. of Pathology, Rawalpindi (Pakistan). Dept. of Microbiolgy

2008-01-15

To find out the frequency of low-level quinolone-resistance in Multi-Drug Resistant (MDR) typhoid using nalidixic acid screening disc. Blood was obtained from suspected cases of typhoid fever and cultured in to BacT/ALERT. The positive blood cultures bottles were subcultured. The isolates were identified by colony morphology and biochemical tests using API-20E galleries. Susceptibility testing of isolates was done by modified Kirby-Bauer disc diffusion method on Muellar Hinton Agar. For the isolates, which were resistant to nalidixic acid by disc diffusion method, Minimal Inhibitory Concentrations (MICs) of ciprofloxacin and nalidixic acid were determined by using the E-test strips. Disc diffusion susceptibility tests and MICs were interpreted according to the guidelines provided by National Committee for Control Laboratory Standard (NCCLS). A total of 21(65.5%) out of 32 isolates of Salmonellae were nalidixic acid-resistant by disk diffusion method. All the nalidixic acid-resistant isolates by disc diffusion method were confirmed by MICs for both ciprofloxacin and nalidixic acid. All the nalidixic acid-resistant isolates had a ciprofloxacin MIC of 0.25-1 microg/ml (reduced susceptibility) and nalidixic acid MICs > 32 microg (resistant). Out of all Salmonella isolates, 24 (75%) were found to be MDR, and all were S. typbi. Low-level quinolone-resistance in typhoid was high in this small series. Screening for nalidixic acid resistance with a 30 microg nalidixic acid disk is a reliable and cost-effective method to detect low-level fluoroquinolone resistance, especially in the developing countries. (author)

Low-level quinolone-resistance in multi-drug resistant typhoid

International Nuclear Information System (INIS)

Mirza, S.H.; Khan, M.A.

2008-01-01

To find out the frequency of low-level quinolone-resistance in Multi-Drug Resistant (MDR) typhoid using nalidixic acid screening disc. Blood was obtained from suspected cases of typhoid fever and cultured in to BacT/ALERT. The positive blood cultures bottles were subcultured. The isolates were identified by colony morphology and biochemical tests using API-20E galleries. Susceptibility testing of isolates was done by modified Kirby-Bauer disc diffusion method on Muellar Hinton Agar. For the isolates, which were resistant to nalidixic acid by disc diffusion method, Minimal Inhibitory Concentrations (MICs) of ciprofloxacin and nalidixic acid were determined by using the E-test strips. Disc diffusion susceptibility tests and MICs were interpreted according to the guidelines provided by National Committee for Control Laboratory Standard (NCCLS). A total of 21(65.5%) out of 32 isolates of Salmonellae were nalidixic acid-resistant by disk diffusion method. All the nalidixic acid-resistant isolates by disc diffusion method were confirmed by MICs for both ciprofloxacin and nalidixic acid. All the nalidixic acid-resistant isolates had a ciprofloxacin MIC of 0.25-1 microg/ml (reduced susceptibility) and nalidixic acid MICs > 32 microg (resistant). Out of all Salmonella isolates, 24 (75%) were found to be MDR, and all were S. typbi. Low-level quinolone-resistance in typhoid was high in this small series. Screening for nalidixic acid resistance with a 30 microg nalidixic acid disk is a reliable and cost-effective method to detect low-level fluoroquinolone resistance, especially in the developing countries. (author)

Cooperative Antibiotic Resistance in a Multi-Drug Environment

Science.gov (United States)

Yurtsev, Eugene; Dai, Lei; Gore, Jeff

2013-03-01

The emergence of antibiotic resistance in bacteria is a significant health concern. A frequent mechanism of antibiotic resistance involves the production of an enzyme which inactivates the antibiotic. By inactivating the antibiotic, resistant cells can ``share'' their resistance with other cells in the bacterial population, suggesting that it may be possible to observe cooperation between strains that inactivate different antibiotics. Here, we experimentally track the population dynamics of two E. coli strains in the presence of two different antibiotics. We find that together the strains are able to grow in antibiotic concentrations that inhibit growth of either of the strains individually. We observe that even when there is stable coexistence between the two strains, the population size of each strain can undergo large oscillations. We expect that our results will provide insight into the evolution of antibiotic resistance and the evolutionary origin of phenotypic diversity and cooperative behaviors.

Reconceptualizing resistance: sociology and the affective dimension of resistance.

Science.gov (United States)

Hynes, Maria

2013-12-01

This paper re-examines the sociological study of resistance in light of growing interest in the concept of affect. Recent claims that we are witness to an 'affective turn' and calls for a 'new sociological empiricism' sensitive to affect indicate an emerging paradigm shift in sociology. Yet, mainstream sociological study of resistance tends to have been largely unaffected by this shift. To this end, this paper presents a case for the significance of affect as a lens by which to approach the study of resistance. My claim is not simply that the forms of actions we would normally recognize as resistance have an affective dimension. Rather, it is that the theory of affect broadens 'resistance' beyond the purview of the two dominant modes of analysis in sociology; namely, the study of macropolitical forms, on the one hand, and the micropolitics of everyday resistance on the other. This broadened perspective challenges the persistent assumption that ideological forms of power and resistance are the most pertinent to the contemporary world, suggesting that much power and resistance today is of a more affective nature. In making this argument, it is a Deleuzian reading of affect that is pursued, which opens up to a level of analysis beyond the common understanding of affect as emotion. I argue that an affective approach to resistance would pay attention to those barely perceptible transitions in power and mobilizations of bodily potential that operate below the conscious perceptions and subjective emotions of social actors. These affective transitions constitute a new site at which both power and resistance operate. © London School of Economics and Political Science 2013.

Exploring Post-Treatment Reversion of Antimicrobial Resistance in Enteric Bacteria of Food Animals as a Resistance Mitigation Strategy.

Science.gov (United States)

Volkova, Victoriya V; KuKanich, Butch; Riviere, Jim E

2016-11-01

Antimicrobial drug use in food animals is associated with an elevation in relative abundance of bacteria resistant to the drug among the animal enteric bacteria. Some of these bacteria are potential foodborne pathogens. Evidence suggests that at least in the enteric nontype-specific Escherichia coli, after treatment the resistance abundance reverts to the background pre-treatment levels, without further interventions. We hypothesize that it is possible to define the distribution of the time period after treatment within which resistance to the administered drug, and possibly other drugs in case of coselection, in fecal bacteria of the treated animals returns to the background pre-treatment levels. Furthermore, it is possible that a novel resistance mitigation strategy for microbiological food safety could be developed based on this resistance reversion phenomenon. The strategy would be conceptually similar to existing antimicrobial drug withdrawal periods, which is a well-established and accepted mitigation strategy for avoiding violative drug residues in the edible products from the treated animals. For developing resistance-relevant withdrawals, a mathematical framework can be used to join the necessary pharmacological, microbiological, and animal production components to project the distributions of the post-treatment resistance reversion periods in the production animal populations for major antimicrobial drug classes in use. The framework can also help guide design of empirical studies into the resistance-relevant withdrawal periods and development of mitigation approaches to reduce the treatment-associated elevation of resistance in animal enteric bacteria. We outline this framework, schematically and through exemplar equations, and how its components could be formulated.

Novel resistance functions uncovered using functional metagenomic investigations of resistance reservoirs

Directory of Open Access Journals (Sweden)

Erica C. Pehrsson

2013-06-01

Full Text Available Rates of infection with antibiotic-resistant bacteria have increased precipitously over the past several decades, with far-reaching healthcare and societal costs. Recent evidence has established a link between antibiotic resistance genes in human pathogens and those found in non-pathogenic, commensal, and environmental organisms, prompting deeper investigation of natural and human-associated reservoirs of antibiotic resistance. Functional metagenomic selections, in which shotgun-cloned DNA fragments are selected for their ability to confer survival to an indicator host, have been increasingly applied to the characterization of many antibiotic resistance reservoirs. These experiments have demonstrated that antibiotic resistance genes are highly diverse and widely distributed, many times bearing little to no similarity to known sequences. Through unbiased selections for survival to antibiotic exposure, functional metagenomics can improve annotations by reducing the discovery of false-positive resistance and by allowing for the identification of previously unrecognizable resistance genes. In this review, we summarize the novel resistance functions uncovered using functional metagenomic investigations of natural and human-impacted resistance reservoirs. Examples of novel antibiotic resistance genes include those highly divergent from known sequences, those for which sequence is entirely unable to predict resistance function, bifunctional resistance genes, and those with unconventional, atypical resistance mechanisms. Overcoming antibiotic resistance in the clinic will require a better understanding of existing resistance reservoirs and the dissemination networks that govern horizontal gene exchange, informing best practices to limit the spread of resistance-conferring genes to human pathogens.

Combating a Global Threat to a Clonal Crop: Banana Black Sigatoka Pathogen Pseudocercospora fijiensis (Synonym Mycosphaerella fijiensis) Genomes Reveal Clues for Disease Control

NARCIS (Netherlands)

Arango Isaza, Rafael E.; Diaz-Trujillo, Caucasella; Dhillon, Braham; Aerts, Andrea; Carlier, Jean; Crane, Charles F.; V. de Jong, Tristan; de Vries, Ineke; Dietrich, Robert; Farmer, Andrew D.; Fortes Fereira, Claudia; Garcia, Suzana; Guzman, Mauricio; Hamelin, Richard C.; Lindquist, Erika A.; Mehrabi, Rahim; Quiros, Olman; Schmutz, Jeremy; Shapiro, Harris; Reynolds, Elizabeth; Scalliet, Gabriel; Souza Manoel, Jr.; Stergiopoulos, Ioannis; Van der Lee, Theo A. J.; De Wit, Pierre J. G. M.; Zapater, Marie-Françoise; Zwiers, Lute-Harm; Grigoriev, Igor V.; Goodwin, Stephen B.; Kema, Gert H. J.

2016-01-01

Black Sigatoka or black leaf streak disease, caused by the ascomycete fungus Pseudocercospora fijiensis, inflicts huge costs on banana producers, due to crop losses and expenses for disease control. The global banana export trade relies on Cavendish clones that are highly susceptible to P.

Glyphosate-Resistant Parthenium hysterophorus in the Caribbean Islands: Non Target Site Resistance and Target Site Resistance in Relation to Resistance Levels.

Directory of Open Access Journals (Sweden)

Enzo Bracamonte

2016-12-01

Full Text Available Glyphosate has been the most intensely herbicide used worldwide for decades, and continues to be a single tool for controlling weeds in woody crops. However, the adoption of this herbicide in a wide range of culture systems has led to the emergence of resistant weeds. Glyphosate has been widely used primarily on citrus in the Caribbean area, but a study of resistance in the Caribbean islands of Cuba and the Dominican Republic has never been carried out. Unfortunately, Parthenium hysterophorus has developed glyphosate-resistance in both islands, independently. The resistance level and mechanisms of different P. hysterophorus accessions (three collected in Cuba (Cu-R and four collected in the Dominican Republic (Do-R have been studied under greenhouse and laboratory conditions. In in vivo assays (glyphosate dose causing 50% reduction in above-ground vegetative biomass and survival, the resistance factor levels showed susceptible accessions (Cu-S≥Do-S, low-resistance accessions (Cu-R3Do-R2>Cu-R2>Do-R3>Do-R4>Cu-R3>>Cu-S≥Do-S. Glyphosate was degraded to aminomethylphosphonic acid, glyoxylate and sarcosine by >88% in resistant accessions except in Cu-R3 and Do-R4 resistant accessions (51.12 and 44.21, respectively, whereas a little glyphosate (<9.32% was degraded in both susceptible accessions at 96 h after treatment. There were significant differences between P. hysterophorus accessions in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS activity enzyme with and without different glyphosate rates. The R accessions showed values of between 0.026 and 0.21 µmol µg-1 TSP protein min-1 basal EPSPS activity values with respect to the S (0.024 and 0.025 accessions. The same trend was found in the EPSPS enzyme activity treated with glyphosate, where a higher enzyme activity inhibition (glyphosate µM corresponded to greater resistance levels in P. hysterophorus accessions. One amino acid substitution was found at position 106 in EPSPS, consisting

Herança da resistência ao enfezamento em milho Inheritance of the resistance to corn stunt

Directory of Open Access Journals (Sweden)

Flávio Trevizoli Silveira

2008-12-01

Full Text Available Os objetivos deste trabalho foram determinar a herança da resistência ao complexo de enfezamento em milho e determinar as melhores fontes de resistência entre as linhagens estudadas. Foram realizadas as análises dialélica e médias de gerações em linhagens de milho. Para a análise dialélica, foram cruzadas 12 linhagens de milho, em dialélico parcial. Para análises de médias de gerações, foram cruzadas três linhagens resistentes e quatro suscetíveis, para a obtenção das gerações F1, F2, RCP R e RCP S. Os trabalhos foram conduzidos em Jaboticabal, SP. A incidência de enfezamento foi avaliada no estádio fenológico R3. Efeitos significativos quanto à capacidade geral de combinação e capacidade específica de combinação foram obtidos, o que indicou que, no controle do caráter enfezamentos, estão envolvidos tanto os efeitos aditivos quanto os de dominância. Análises de médias de gerações mostraram a presença de poucos genes envolvidos com o controle da resistência, com predominância de efeitos aditivos, o que permite a seleção de genótipos resistentes. As linhagens L02, L03 e L05 poderão ser utilizadas como fontes de resistência, em futuras combinações híbridas.The objectives of this work were to determine the inheritance of resistance to corn stunt and determine the best resistance sources among the studied inbred lines. Diallel analysis and generation means were made for corn inbred lines. For the diallel analysis, twelve corn-inbred lines were crossed, in a partial diallel scheme. For the analyses of generation means, three resistant inbred lines and four susceptible ones were crossed, to obtain the F1, F2, RCP R and RCP S generations. The experiments were carried out in Jaboticabal, SP, Brazil. Corn sfunt incidence was evaluated at the phenological phase R3. Significant effects for CGC and CEC were obtained, which indicated that both additive and dominance effects were involved in corn expression of

Reduction of cellular cisplatin resistance by hyperthermia - a review

NARCIS (Netherlands)

Hettinga, JVE; Konings, AWT; Kampinga, HH

1997-01-01

Resistance to cisplatin (cDDP) is a major limitation to its clinical effectiveness. Review of literature data indicates that cDDP resistance is a multifactorial phenomenon. This provides an explanation why attempts to reverse or circumvent resistance using cDDP-analogues or combination therapy with

Impact of extensive antibiotic treatment on faecal carriage of antibiotic-resistant enterobacteria in children in a low resistance prevalence setting

Science.gov (United States)

Brandtzaeg, Petter; Høiby, E. Arne; Bohlin, Jon; Samuelsen, Ørjan; Steinbakk, Martin; Abrahamsen, Tore G.; Müller, Fredrik; Gammelsrud, Karianne Wiger

2017-01-01

We prospectively studied the consequences of extensive antibiotic treatment on faecal carriage of antibiotic-resistant enterobacteria in a cohort of children with cystic fibrosis (CF) and a cohort of children with cancer compared to healthy children with no or low antibiotic exposure. The study was conducted in Norway in a low resistance prevalence setting. Sixty longitudinally collected faecal samples from children with CF (n = 32), 88 samples from children with cancer (n = 45) and 127 samples from healthy children (n = 70) were examined. A direct MIC-gradient strip method was used to detect resistant Enterobacteriaceae by applying Etest strips directly onto agar-plates swabbed with faecal samples. Whole genome sequencing (WGS) data were analysed to identify resistance mechanisms in 28 multidrug-resistant Escherichia coli isolates. The prevalence of resistance to third-generation cephalosporins, gentamicin and ciprofloxacin was low in all the study groups. At inclusion the prevalence of ampicillin-resistant E. coli and trimethoprim-sulfamethoxazole-resistant E. coli in the CF group compared to healthy controls was 58.6% vs. 28.4% (p = 0.005) and 48.3% vs. 14.9% (p = 0.001), respectively, with a similar prevalence at the end of the study. The prevalence of resistant enterobacteria was not significantly different in the children with cancer compared to the healthy children, not even at the end of the study when the children with cancer had been treated with repeated courses of broad-spectrum antibiotics. Children with cancer were mainly treated with intravenous antibiotics, while the CF group mainly received peroral treatment. Our observations indicate that the mode of administration of antibiotics and the general level of antimicrobial resistance in the community may have an impact on emergence of resistance in intestinal enterobacteria during antibiotic treatment. The WGS analyses detected acquired resistance genes and/or chromosomal mutations that explained the

Determining resistance to mastitis in a bovine subject comprises detecting the presence or absence of a genetic marker that is linked to a trait indicative of mastitis resistance

DEFF Research Database (Denmark)

2007-01-01

The invention relates to a method for determining mastitis resistance in bovine subjects, wherein mastitis resistance comprise resistance to both sub-clinical and clinical mastitis. In particular, the method of the invention involves identification of genetic markers and/or Quantitative Trait Locus...... (QTL) for the determination of mastitis resistance in a bovine subject. The determination of mastitis resistance involves resolution of the specific microsatellite status. Furthermore, the invention relates to a diagnostic kit for detection of genetic marker(s) associated with mastitis resistance....... The method and kit of the present invention can be applied for selection of bovine subjects for breeding purposes. Thus, the invention provides a method of genetically selecting bovine subjects with mastitis resistance, thereby yielding cows less prone to mastitis...

Equivalent network for resistance and temperature coefficient of resistance versus temperature and composition of thick resistive films

International Nuclear Information System (INIS)

Kusy, A.

1987-01-01

Two types of elementary resistances in thick resistive films have been considered: (i) constriction resistance R/sub C/ determined by the bulk properties of conducting material and by the geometry of constriction, and (ii) barrier resistance R/sub B/ determined by the parameters of a thermally activated type of tunneling process and by the geometry of the metal-insulator-metal unit. On this basis a resistance network composed of a large number of the two types of resistances has been defined. The network has been considered as being equivalent to thick resistive film (TRF) from the point of view of the resistance and temperature coefficient of resistance (TCR). The parameters of this network have been evaluated by the computer-aided approximation of the experimental data found for RuO 2 -based TRFs. On the basis of the equations derived for the network as well as the results of the approximation process, it can be concluded that the small values of the network TCR result from the superposition of the TCR of the conducting component β/sub C/ and of the temperature coefficient of barrier resistance α/sub B/. In this superposition β/sub C/ is attenuated (by 1--2 orders of magnitude), while α/sub B/ is attenuated by only few percentages. The network has been found to be strongly barrier dominated

Understanding Rifampicin Resistance in Tuberculosis through a Computational Approach

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Satish Kumar

2014-12-01

Full Text Available The disease tuberculosis, caused by Mycobacterium tuberculosis (MTB, remains a major cause of morbidity and mortality in developing countries. The evolution of drug-resistant tuberculosis causes a foremost threat to global health. Most drug-resistant MTB clinical strains are showing resistance to isoniazid and rifampicin (RIF, the frontline anti-tuberculosis drugs. Mutation in rpoB, the beta subunit of DNA-directed RNA polymerase of MTB, is reported to be a major cause of RIF resistance. Amongst mutations in the well-defined 81-base-pair central region of the rpoB gene, mutation at codon 450 (S450L and 445 (H445Y is mainly associated with RIF resistance. In this study, we modeled two resistant mutants of rpoB (S450L and H445Y using Modeller9v10 and performed a docking analysis with RIF using AutoDock4.2 and compared the docking results of these mutants with the wild-type rpoB. The docking results revealed that RIF more effectively inhibited the wild-type rpoB with low binding energy than rpoB mutants. The rpoB mutants interacted with RIF with positive binding energy, revealing the incapableness of RIF inhibition and thus showing resistance. Subsequently, this was verified by molecular dynamics simulations. This in silico evidence may help us understand RIF resistance in rpoB mutant strains.

A TECHNIQUE OF MEASURING OF RESISTANCE OF A GROUNDING DEVICE

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I.V. Nizhevskyi

2016-06-01

Full Text Available Introduction. Measurement of resistance of the grounding device (GD by means of a three-electrode system. This requires not only the right choice of installation locations of measuring electrodes, but also the determination of the point of zero potential. Implementation of these requirements quite time-consuming, and in some cases impossible. Aim. Develop a new technique for measuring the electrical resistance of the GD. Task. The method of measuring the resistance of the GD with the help of a three-electrode setup is necessary to exclude the determination of the point of zero potential. Method. Mathematical modeling and calculation engine. Results. A three-electrode system for measuring the resistance of grounding devices (GD for various purposes is considered. On the basis of Maxwell equations a theoretical substantiation of a new technique for measuring the resistance of any GD of any construction in random soil structure has been proposed. An equation system of the sixth order has been obtained, its solution makes it possible to measure its own mutual resistance in the three-electrode installation with sufficiently high accuracy. Peculiarities of drawing up a calculation scheme of substitution of a three-electrode installation with lumped parameters: self and mutual impedance. Use of the principle of reciprocity eliminates the need of finding a point of zero potential which is a rather difficult task. The technique allows to minimize the spacing of measuring electrodes outside the GD, which substantially reduces the length of wiring of the measurement circuit and increases the «signal-to-interference» ratio and also removes the restrictions on the development of the territory outside the GD being tested. Conclusion. The procedure allows to evaluate the self and mutual impedance grounding all the electrodes in a three-electrode measuring installation of the grounding resistance of the device without finding the point of zero potential.

Review of resistance factor for steel: resistance distributions and resistance factor calibration

International Nuclear Information System (INIS)

Schmidt, B.J.; Bartlett, F.M.

2002-01-01

Changes in the Canadian steel industry warrant a review of the steel resistance factor in CSA Standard S16 (formerly S16.1) 'Limit states design of steel structures', originally calibrated in the landmark study by Kennedy and Gad Aly in 1980. This paper presents statistical parameters for the bending, compression, and tension resistances of W, WWF, and HSS components produced since 1999 that have been derived from geometric and material properties presented in a companion paper. The resistance factor for steel was recalibrated for the live and dead load combination in the 1995 National Building Code of Canada. A resistance factor of 0.95 is suitable for laterally supported beams, stocky columns, and tension members failing by yield of the gross section, whereas the current value of 0.90 is appropriate for intermediate columns and tension members failing by fracture of the net section. (author)

Frequency of colistin and fosfomycin resistance in carbapenem-resistant Enterobacteriaceae from a tertiary care hospital in Karachi

Directory of Open Access Journals (Sweden)

Qamar S

2017-07-01

Full Text Available Salima Qamar, Najma Shaheen, Sadia Shakoor, Joveria Farooqi, Kauser Jabeen, Rumina Hasan Clinical Microbiology, Department of Pathology And Laboratory Medicine, Aga Khan University Hospital, Karachi, Pakistan Introduction: Management of infections with carbapenem-resistant Enterobacteriaceae (CRE is challenging. In recent times, agents such as colistin and fosfomycin have been used in combination with other antibiotics to treat such infections. In this study, we aim to seek frequency of colistin and fosfomycin resistance in CRE from Pakistan.Methods: This study was conducted at clinical laboratories, Aga Khan University Hospital. In total, 251 CRE were included in the study. Colistin minimum inhibitory concentrations (MICs were performed using broth microdilution (BMD method and VITEK® 2 system, whereas fosfomycin susceptibility was performed using Kirby–Bauer method. MIC50 and MIC90 were calculated for colistin and agreement between VITEK and BMD was also calculated.Results: Out of 251 strains colistin MIC of ≥4 µg/mL was seen in 40 (15.9%. Of these strains 20 (50% were Klebsiella pneumoniae. Colistin MIC50 and MIC90 were found to be 0.5 and 16 µg/mL, respectively. BMD and VITEK 2 showed 100% categorical agreement. Essential agreement was 88.5% with kappa score 0.733 indicating strong agreement between VITEK and BMD. 31 out of 251 (12.3% CREs were resistant to fosfomycin.Conclusion: Study shows frequency of colistin and fosfomycin resistance to be 15.9% and 12.3%, respectively. In countries where rate of CREs is high, emerging resistance against these last resort antibiotics is alarming as it leaves clinicians with almost no options to manage such multidrug resistant and extensively drug resistant infections. Keywords: emerging drug resistance, colistin resistance, fosfomycin resistance, carbapenam resistant enterobacteriaceae, salvage antibiotics 

Rapid emergence of ciprofloxacin-resistant enterobacteriaceae containing multiple gentamicin resistance-associated integrons in a Dutch hospital

NARCIS (Netherlands)

C. van der Schee (Cindy); N. Lemmens-den Toom (Nicole); M.C. Vos (Margreet); P.J. Lugtenburg (Pieternella); S. de Marie (Siem); H.A. Verbrugh (Henri); B. Löwenberg (Bob); W.H.F. Goessens (Wil); A.F. van Belkum (Alex); J.J. Cornelissen (Jan); H.P. Endtz (Hubert)

2001-01-01

textabstractIn a hematology unit in the Netherlands, the incidence of ciprofloxacin-resistant Enterobacter cloacae and Escherichia coli increased from from 1996 to 1999. Clonal spread of single genotypes of both ciprofloxacin-resistant E. coli and Enterobacter cloacae from

Outbreak of carbapenem-resistant Providencia rettgeri in a tertiary hospital

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V S Tshisevhe

2017-01-01

Full Text Available The emergence of resistance to multiple antimicrobial agents in pathogenic bacteria is a significant public health threat, as there are limited effective antimicrobial agents for infections caused by multidrug-resistant (MDR bacteria. Several MDR bacteria are now frequently detected. Carbapenem resistance in Enterobacteriaceae is often plasmid mediated, necessitating stringent infection control practices. We describe an outbreak of carbapenem-resistant Providencia rettgeri involving 4 patients admitted to intensive care and high-care units at a tertiary hospital. Clinical and demographic characteristics of 4 patients with carbapenem-resistant P. rettgeri were documented. All P. rettgeri isolated in these cases had a carbapenem-resistant antibiogram, with resistance to imipenem, ertapenem and meropenem. These cases could be epidemiologically linked. A multiprong approach, simultaneously targeting antibiotic stewardship, universal precautions and appropriate transmission-based precaution practices, is integral to prevention and control of nosocomial infections.

A novel surrogate index for hepatic insulin resistance.

LENUS (Irish Health Repository)

Vangipurapu, J

2011-03-01

In epidemiological and genetic studies surrogate indices are needed to investigate insulin resistance in different insulin-sensitive tissues. Our objective was to develop a surrogate index for hepatic insulin resistance.

Expression profiling and functional analyses of BghPTR2, a peptide transporter from Blumeria graminis f. sp. hordei

DEFF Research Database (Denmark)

Droce, Aida; Holm, Kirsten B.; Olsson, Stefan

2015-01-01

The obligate ascomycete parasitic fungus Blumeria graminis f. sp. hordei (Bgh) has a unique lifestyle as it is completely dependent on living barley leaves as substrate for growth. Genes involved in inorganic nitrogen utilization are notably lacking, and the fungus relies on uptake of host...

A simple culture method inducing sexual reproduction by Fusarium graminearum, the primary causal agent of Fusarium head blight

Science.gov (United States)

The homothallic ascomycete fungus Fusarium graminearum is the primary causal agent of Fusarium head blight (FHB), a devastating disease of wheat and barley worldwide. The fungus undergoes both asexual and sexual stages in its life cycle. The asexual stage produces conidiospores, whereas the sexual s...

Induced resistance: an enhancement of basal resistance?

NARCIS (Netherlands)

Vos, M. de; Robben, C.; Pelt, J.A. van; Loon, L.C. van; Pieterse, C.M.J.

2002-01-01

Upon primary pathogen attack, plants activate resistance mechanisms at the site of infection. Besides this so-called basal resistance, plants have also the ability to enhance their defensive capacity against future pathogen attack. There are at least two types of biologically induced resistance.

Assessing resistance of stabilized corrosion resistant steels to intergranular corrosion

International Nuclear Information System (INIS)

Karas, A.; Cihal, V. Jr.; Vanek, V.; Herzan, J.; Protiva, K.; Cihal, V.

1987-01-01

Resistance to intergranular corrosion was determined for four types of titanium-stabilized steels from the coefficients of stabilization efficiency according to the degree the chemical composition was known. The ATA SUPER steel showed the highest resistance parameter value. The resistance of this type of steel of a specific composition, showing a relatively low value of mean nitrogen content was compared with steel of an optimized chemical composition and with low-carbon niobium stabilized, molybdenum modified steels. The comparison showed guarantees of a sufficient resistance of the steel to intergranular corrosion. The method of assessing the resistance to intergranular corrosion using the calculation of the minimum content of Cr', i.e., the effective chromium content, and the maximum effective carbon content C' giving the resistance parameter k seems to be prospective for practical use in the production of corrosion resistant steels. (author). 1 tab., 5 figs., 15 refs

Fluconazole resistance in Candida species: a current perspective

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Berkow EL

2017-07-01

Full Text Available Elizabeth L Berkow, Shawn R Lockhart Mycotic Diseases Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA Abstract: Candida albicans and the emerging non-albicans Candida spp. have significant clinical relevance among many patient populations. Current treatment guidelines include fluconazole as a primary therapeutic option for the treatment of these infections, but it is only fungistatic against Candida spp. and both inherent and acquired resistance to fluconazole have been reported. Such mechanisms of resistance include increased drug efflux, alteration or increase in the drug target, and development of compensatory pathways for producing the target sterol, ergosterol. While many mechanisms of resistance observed in C. albicans are also found in the non-albicans species, there are also important and unexpected differences between species. Furthermore, mechanisms of fluconazole resistance in emerging Candida spp., including the global health threat Candida auris, are largely unknown. In order to preserve the utility of one of our fundamental antifungal drugs, fluconazole, it is essential that we fully appreciate the manner by which Candida spp. manifest resistance to it. Keywords: Candida, fluconazole resistance, ERG11, drug efflux, ergosterol

Resistant Hypertension.

Science.gov (United States)

Doroszko, Adrian; Janus, Agnieszka; Szahidewicz-Krupska, Ewa; Mazur, Grzegorz; Derkacz, Arkadiusz

2016-01-01

Resistant hypertension is a severe medical condition which is estimated to appear in 9-18% of hypertensive patients. Due to higher cardiovascular risk, this disorder requires special diagnosis and treatment. The heterogeneous etiology, risk factors and comorbidities of resistant hypertension stand in need of sophisticated evaluation to confirm the diagnosis and select the best therapeutic options, which should consider lifestyle modifications as well as pharmacological and interventional treatment. After having excluded pseudohypertension, inappropriate blood pressure measurement and control as well as the white coat effect, suspicion of resistant hypertension requires an analysis of drugs which the hypertensive patient is treated with. According to one definition - ineffective treatment with 3 or more antihypertensive drugs including diuretics makes it possible to diagnose resistant hypertension. A multidrug therapy including angiotensin - converting enzyme inhibitors, angiotensin II receptor blockers, beta blockers, diuretics, long-acting calcium channel blockers and mineralocorticoid receptor antagonists has been demonstrated to be effective in resistant hypertension treatment. Nevertheless, optional, innovative therapies, e.g. a renal denervation or baroreflex activation, may create a novel pathway of blood pressure lowering procedures. The right diagnosis of this disease needs to eliminate the secondary causes of resistant hypertension e.g. obstructive sleep apnea, atherosclerosis and renal or hormonal disorders. This paper briefly summarizes the identification of the causes of resistant hypertension and therapeutic strategies, which may contribute to the proper diagnosis and an improvement of the long term management of resistant hypertension.

Genetic resistance to marrow transplantation as a leukemia defense mechanism

International Nuclear Information System (INIS)

Gallagher, M.T.; Lotzova, E.; Trentin, J.J.

1976-01-01

The normal role of genetic resistance to bone marrow transplantation was investigated. It is demonstrated, using three different systems e.g. colony studies in the spleen, spleen weight studies and mortality studies, that irradiated or unirradiated mice which show genetic resistance are able to recognize and reject intravenously transplanted parental lymphoma cells, while they accept normal parental bone marrow cells. Either the lymphoma cells have a new antigen which is recognized and reacted to by the cells responsible for genetic resistance and, or, bone marrow cells have a low level of Hh antigen which is increased greatly by the lymphoma transformation process, thereby resulting in the rejection of the lymphoma cells by the cells responsible for genetic resistance. Lymphoma resistance as well as genetic resistance can be overridden by increasing the number of cells injected. Genetic resistance seems to be restricted to the spleen and bone marrow. There is evidence that the normal biological role for genetic resistance may be lymphoma-leukemia surveillance

Action and resistance mechanisms of antibiotics: A guide for clinicians

Directory of Open Access Journals (Sweden)

Garima Kapoor

2017-01-01

Full Text Available Infections account for a major cause of death throughout the developing world. This is mainly due to the emergence of newer infectious agents and more specifically due to the appearance of antimicrobial resistance. With time, the bacteria have become smarter and along with it, massive imprudent usage of antibiotics in clinical practice has resulted in resistance of bacteria to antimicrobial agents. The antimicrobial resistance is recognized as a major problem in the treatment of microbial infections. The biochemical resistance mechanisms used by bacteria include the following: antibiotic inactivation, target modification, altered permeability, and “bypass” of metabolic pathway. Determination of bacterial resistance to antibiotics of all classes (phenotypes and mutations that are responsible for bacterial resistance to antibiotics (genetic analysis are helpful. Better understanding of the mechanisms of antibiotic resistance will help clinicians regarding usage of antibiotics in different situations. This review discusses the mechanism of action and resistance development in commonly used antimicrobials.

Beyond multidrug-resistant tuberculosis in Europe: a TBNET study

NARCIS (Netherlands)

Günther, G.; van Leth, F.; Altet, N.; Dedicoat, M.; Duarte, R.; Gualano, G.; Kunst, H.; Muylle, I.; Spinu, V.; Tiberi, S.; Viiklepp, P.; Lange, C.; Alexandru, S.; Cernenco, I.; Ciobanu, A.; Donica, A.; Cayla, J.; Fina, L.; Galvao, M. L. de Souza; Maldonado, J.; Avsar, K.; Bang, D.; Andersen, A. B.; Barbuta, R.; Dubceac, V.; Bothamley, G.; Crudu, V.; Davilovits, M.; Atunes, A.; de Lange, W.; Leimane, V.; Rusmane, L.; de Lorenzo, S.; Cuppen, F.; de Guchtenaire, I.; Magis-Escurra, C.; McLaughlin, A.-M.; Meesters, R.; te Pas, M.; Prins, B.; Mütterlein, R.; Kotrbova, J.; Polcová, V.; Vasakova, M.; Pontali, E.; Rumetshofer, R.; Rowhani, M.; Skrahina, A.; Avchinko, V.; Katovich, D.

2015-01-01

The emergence of drug-resistant tuberculosis (TB) is a challenge to TB control in Europe. We evaluated second-line drug susceptibility testing in Mycobacterium tuberculosis isolates from patients with multidrug-resistant, pre-extensively drug-resistant (pre-XDR-TB) and XDR-TB at 23 TBNET sites in 16

Evolutionary Origin of Antibiotic Resistance, A Historical Perspective

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Yamile Adriana Celis Bustos

2017-07-01

Full Text Available Antimicrobial resistance is a natural aspect of bacterial evolution that can result from mutations or acquisition of foreign genes. Various views on the origin of this resistance explain the ability of these organisms to acquire new features. Lamarck andDarwin’s theories of evolution have led to experiments designed to explore the origin of bacterial variation and the emergence of new features. These experiments show that antimicrobial resistance is related to mutations in chromosomal genes and/or transfer of extrachromosomal genetic elements that can be expressed based on the antibiotic pressure exerted. The main experiments and findings that seek to explain the phenomenon of antibiotic resistance are reviewed here in.

F2 screen, inheritance and cross-resistance of field-derived Vip3A resistance in Spodoptera frugiperda (Lepidoptera: Noctuidae) collected from Louisiana, USA.

Science.gov (United States)

Yang, Fei; Morsello, Shannon; Head, Graham P; Sansone, Chris; Huang, Fangneng; Gilreath, Ryan T; Kerns, David L

2017-11-28

Fall armyworm, Spodoptera frugiperda, is a target pest of the Vip3A protein used in pyramided Bt corn and cotton in the USA. In this study, we provide the first documentation of a resistance allele conferring Vip3A resistance in a field-derived population of S. frugiperda from the USA, and characterize its inheritance and cross-resistance. An F 2 screen with 104 two-parent families generated from a field collection of S. frugiperda in Louisiana, USA, resulted in one family carrying a Vip3A resistance allele. The Vip3A-resistant strain (RR) derived from the two-parent family showed a high level of resistance to Vip3A in both diet and whole-plant bioassays, with a resistance ratio of >632.0-fold relative to a susceptible population (SS) based on diet-overlay bioassays. The inheritance of Vip3A resistance was monogenic, autosomal and recessive. Furthermore, the Vip3A resistance conferred no cross-resistance to Cry1F, Cry2Ab2 or Cry2Ae purified proteins, with resistance ratios of 3.5, 5.0 and 1.1, respectively. These findings provide valuable information for characterizing Vip3A resistance, resistance monitoring, and developing effective resistance management strategies for the sustainable use of the Vip3A technology. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Neratinib resistance and cross-resistance to other HER2-targeted drugs due to increased activity of metabolism enzyme cytochrome P4503A4.

Science.gov (United States)

Breslin, Susan; Lowry, Michelle C; O'Driscoll, Lorraine

2017-02-28

Neratinib is in Phase 3 clinical trials but, unfortunately, the development of resistance is inevitable. Here, we investigated the effects of acquired neratinib resistance on cellular phenotype and the potential mechanism of this resistance. Neratinib-resistant variants of HER2-positive breast cancer cells were developed and their cross-resistance investigated using cytotoxicity assays. Similarly, sensitivity of trastuzumab-resistant and lapatinib-resistant cells to neratinib was assessed. Cellular phenotype changes were evaluated using migration, invasion and anoikis assays. Immunoblotting for HER family members and drug efflux pumps, as well as enzyme activity assays were performed. Neratinib resistance conferred cross-resistance to trastuzumab, lapatinib and afatinib. Furthermore, the efficacy of neratinib was reduced in trastuzumab- and lapatinib-resistant cells. Neratinib-resistant cells were more aggressive than their drug-sensitive counterparts, with increased CYP3A4 activity identified as a novel mechanism of neratinib resistance. The potential of increased CYP3A4 activity as a biomarker and/or target to add value to neratinib warrants investigation.

Authenticating a tamper-resistant module in a base station router

NARCIS (Netherlands)

Bosch, H.G.P.; Kraml, M.; Mullender, Sape J.; Polakos, P.; Samuel, L.G.

2007-01-01

The present invention provides a method involving a tamper-resistant module and an authentication server. The method includes receiving, at the tamper-resistant module, information encrypted using a first secret key stored in the authentication server. The method also includes authenticating the

Monitoring of Leachate Recirculation in a Bioreactor Using Electrical Resistivity

Science.gov (United States)

Grellier, S.; Bureau, N.; Robain, H.; Tabbagh, A.; Camerlynck, C.; Guerin, R.

2004-05-01

The bioreactor is a concept of waste landfill management consisting in speeding up the biodegradation by optimizing the moisture content through leachate recirculation. Electrical resistivity tomography (ERT) is carried out with fast resistivity-meter (Syscal Pro, IRIS Instruments, developed in the framework of the research project CERBERE 01V0665-69, funded by the French Research Ministry) to monitor leachate recirculation. During a recirculation period waste moisture increases, so that electrical resistivity may decrease, but at the same time temperature and mineralization of both waste and leachate become intermixed. If waste temperature is much higher than leachate temperature electrical resistivity will not decrease as much as if the temperature difference was smaller. If leachate mineralization (i.e. leachate conductivity) is higher than that of wet waste in the landfill, electrical resistivity will tend to decrease. Otherwise for example after an addition of rain water into the leachate storage or in case of very wet waste, the resistivities of each medium (leachate and wet waste) can be almost the same, so that leachate mineralization will not have a great influence on waste resistivity. Resistivity measurements were performed during 85 minutes injection trials (with a discharge of 20 m3 h-1) where leachate was injected through a vertical borehole perforated between 1.85 and 4.15 m. Three first measurements are made during the injection (3, 30 and 60 minutes from the beginning of the injection) and the two other after the injection period (8 and 72 minutes after the end of the injection). Apparent and interpreted resistivity variations that occurred during injection trials, expressed as the relative differences (in %) between apparent, respectively interpreted, resistivity during injection and apparent, respectively interpreted, resistivity before injection (reference measurement) show the formation of a plume (a negative anomaly: resistivity decreases with

Induced mutations for horizontal resistance. A model study using leaf rust resistance in wheat

International Nuclear Information System (INIS)

Chopra, V.L.; Sawhney, R.N.; Kumar, R.

1983-01-01

A mutant with seemingly non-specific resistance to leaf rust was obtained some time ago from the wheat variety Kharchia Local treated with NMH. This mutant is being studied genetically and in its disease reaction by laboratories in Australia, Canada and India in co-operation. The mutant showed a dominant inheritance of resistance in F 1 , but different segregation in F 2 and F 3 . This peculiar genetic behaviour has so far not been explained. (author)

Biotechnology of non-Saccharomyces yeasts-the basidiomycetes.

Science.gov (United States)

Johnson, Eric A

2013-09-01

Yeasts are the major producer of biotechnology products worldwide, exceeding production in capacity and economic revenues of other groups of industrial microorganisms. Yeasts have wide-ranging fundamental and industrial importance in scientific, food, medical, and agricultural disciplines (Fig. 1). Saccharomyces is the most important genus of yeast from fundamental and applied perspectives and has been expansively studied. Non-Saccharomyces yeasts (non-conventional yeasts) including members of the Ascomycetes and Basidiomycetes also have substantial current utility and potential applicability in biotechnology. In an earlier mini-review, "Biotechnology of non-Saccharomyces yeasts-the ascomycetes" (Johnson Appl Microb Biotechnol 97: 503-517, 2013), the extensive biotechnological utility and potential of ascomycetous yeasts are described. Ascomycetous yeasts are particularly important in food and ethanol formation, production of single-cell protein, feeds and fodder, heterologous production of proteins and enzymes, and as model and fundamental organisms for the delineation of genes and their function in mammalian and human metabolism and disease processes. In contrast, the roles of basidiomycetous yeasts in biotechnology have mainly been evaluated only in the past few decades and compared to the ascomycetous yeasts and currently have limited industrial utility. From a biotechnology perspective, the basidiomycetous yeasts are known mainly for the production of enzymes used in pharmaceutical and chemical synthesis, for production of certain classes of primary and secondary metabolites such as terpenoids and carotenoids, for aerobic catabolism of complex carbon sources, and for bioremediation of environmental pollutants and xenotoxicants. Notwithstanding, the basidiomycetous yeasts appear to have considerable potential in biotechnology owing to their catabolic utilities, formation of enzymes acting on recalcitrant substrates, and through the production of unique primary

Sponge microbiota are a reservoir of functional antibiotic resistance genes

Directory of Open Access Journals (Sweden)

Dennis Versluis

2016-11-01

Full Text Available Wide application of antibiotics has contributed to the evolution of multi-drug resistant human pathogens, resulting in poorer treatment outcomes for infections. In the marine environment, seawater samples have been investigated as a resistance reservoir; however, no studies have methodically examined sponges as a reservoir of antibiotic resistance. Sponges could be important in this respect because they often contain diverse microbial communities that have the capacity to produce bioactive metabolites. Here, we applied functional metagenomics to study the presence and diversity of functional resistance genes in the sponges Aplysina aerophoba, Petrosia ficiformis and Corticium candelabrum. We obtained 37 insert sequences facilitating resistance to D-cycloserine (n=6, gentamicin (n=1, amikacin (n=7, trimethoprim (n=17, chloramphenicol (n=1, rifampicin (n=2 and ampicillin (n=3. Fifteen of 37 inserts harboured resistance genes that shared <90% amino acid identity with known gene products, whereas on 13 inserts no resistance gene could be identified with high confidence, in which case we predicted resistance to be mainly mediated by antibiotic efflux. One marine-specific ampicillin-resistance-conferring β-lactamase was identified in the genus Pseudovibrio with 41% global amino acid identity to the closest β-lactamase with demonstrated functionality, and subsequently classified into a new family termed PSV. Taken together, our results show that sponge microbiota host diverse and novel resistance genes that may be harnessed by phylogenetically distinct bacteria.

Antimicrobial resistance in Neisseria gonorrhoeae in China: a meta-analysis.

Science.gov (United States)

Chen, Yawen; Gong, Yanhong; Yang, Tingting; Song, Xingyue; Li, Jing; Gan, Yong; Yin, Xiaoxv; Lu, Zuxun

2016-03-03

Neisseria gonorrhoeae (N. gonorrhoeae) resistance to antimicrobial has been a major concern in China, and epidemiological data on N. gonorrhoeae resistance are not well understood. This meta-analysis was aimed at summarizing the evidence on N. gonorrhoeae resistance to penicillin, tetracycline, ciprofloxacin, ceftriaxone and spectinomycin in China. Two researchers independently searched five databases to identify studies on N. gonorrhoeae resistance to antimicrobials from the databases' inception to November 7, 2014. A random-effects model was used to estimate the antimicrobial resistance rates and their corresponding 95% confidence intervals (CIs). Publication bias was assessed with the Begg rank correlation test and the Egger test. We included 127 studies in our synthesis reporting antimicrobial resistance. Our analyses demonstrated that N. gonorrhoeae resistance to penicillin and tetracycline respectively increased from 74.41% (95% CI: 64.1-84.7%) and 68.3% (95% CI: 58.7-78.0%) in 2000 to 84.2% (95% CI: 79.7-88.8%) and 82.4% (95% CI: 79.9-84.7%) in 2012. N. gonorrhoeae resistance to ciprofloxacin experienced a steady increase from 12.7% (95% CI, 8.6-16.7%) in 1995 and reached 93.8% (95% CI: 91.9-95.7%) in 2003. N. gonorrhoeae resistance to ceftriaxone was 1.7% (95% CI: 0.5-5.7%) before 1995 and 0.5% (95% CI: 0.2-1.4%) in 2012, and N. gonorrhoeae resistance to spectinomycin was less than 2% from 1995 to 2012. N. gonorrhoeae resistance rates to penicillin, tetracycline and ciprofloxacin were high in China. Ceftriaxone and spectinomycin remained effective therapy for the treatment of gonorrhea. It is essential to strengthen N. gonorrhoeae resistance surveillance and update treatment guidelines timely.

Dissemination of antibiotic resistance in methicillin-resistant Staphylococcus aureus and vancomycin-resistant S aureus strains isolated from hospital effluents.

Science.gov (United States)

Mandal, Santi M; Ghosh, Ananta K; Pati, Bikas R

2015-12-01

Vancomycin-resistant Staphylococcus aureus (VRSA) and methicillin-resistant S aureus (MRSA) strains were examined in hospital effluents. Most S aureus strains are resistant to methicillin (MRSA), followed by tetracycline. Approximately 15% of MRSA strains are also resistant to vancomycin (VRSA). All VRSA strains developed a VanR/VanS-regulated 2-component system of VanA-type resistance in their genome. Results indicate that there is a possibility of developing resistance to aminoglycosides by VRSA strains in the near future. Copyright © 2015 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Emergence and dissemination of antibiotic resistance: A global problem

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R Choudhury

2012-01-01

Full Text Available Antibiotic resistance is a major problem in clinical health settings. Interestingly the origin of many of antibiotic resistance mechanisms can be traced back to non-pathogenic environmental organisms. Important factors leading to the emergence and spread of antibiotic resistance include absence of regulation in the use of antibiotics, improper waste disposal and associated transmission of antibiotic resistance genes in the community through commensals. In this review, we discussed the impact of globalisation on the transmission of antibiotic resistance genes in bacteria through immigration and export/import of foodstuff. The significance of surveillance to define appropriate use of antibiotics in the clinic has been included as an important preventive measure.

Antibiotic resistance: a physicist’s view

Science.gov (United States)

Allen, Rosalind; Waclaw, Bartłomiej

2016-08-01

The problem of antibiotic resistance poses challenges across many disciplines. One such challenge is to understand the fundamental science of how antibiotics work, and how resistance to them can emerge. This is an area where physicists can make important contributions. Here, we highlight cases where this is already happening, and suggest directions for further physics involvement in antimicrobial research.

Starmerella syriaca f.a., sp. nov., an osmotolerant yeast species isolated from flowers in Syria.

Science.gov (United States)

Sipiczki, Matthias

2015-04-01

Four strains of a novel asexual ascomycetous yeast species were isolated from Malva sp. flowers in Syria. Sequencing of the regions spanning the small subunit, 5.8S, and the D1/D2 domains of the large subunit ribosomal RNA genes showed that the isolates were conspecific. Comparative analysis of these sequences and the corresponding sequences of the type strains of ascomycetous yeasts revealed that the novel species is phylogenetically related to members of the Starmerella clade. Its closest relative is Candida vaccinii. For the new species the name Starmerella syriaca is proposed. Its strains are osmotolerant and produce pseudohypha-like structures capable of penetrating agar media. The type strain is 2-1362(T) (=CBS 13909(T) = NCAIM Y.02138(T) = CCY 090-003-001(T)). The GenBank accession numbers for its nucleotide sequences are: JX515986 (D1/D2 LSU), JX515987 (ITS1-5.8S-ITS2) and JX515988 (SSU). Mycobank: MB 810090.

Antibacterial Resistance in African Catfish Aquaculture: a Review

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Madubuike U. ANYANWU

2016-03-01

Full Text Available Antibacterial resistance (AR is currently one of the greatest threats to mankind as it constitutes health crisis. Extensive use of antibacterial agents in human and veterinary medicine, and farm crops have resulted in emergence of antibacterial-resistant organisms in different environmental settings including aquaculture. Antibacterial resistance in aquaculture is a serious global concern because antibacterial resistance genes (ARGs can be transferred easily from aquaculture setting to other ecosystems and the food chain. African catfish (ACF aquaculture has increased at a phenomenal rate through a continuous process of intensification, expansion and diversification. Risk of bacterial diseases has also increased and consequently there is increased use of antibacterial agents for treatment. Antibacterial resistance in ACF aquaculture has huge impact on the food chain and thus represents risk to public and animal health. In “one health” approach of curbing AR, knowledge of the sources, mechanisms and magnitude of AR in ACF aquaculture and its potential impact on the food chain is important in designing and prioritizing monitoring programs that may generate data that would be relevant for performing quantitative risk assessments, implementation of antibacterial stewardship plans, and developing effective treatment strategies for the control of ACF disease and reducing risk to public health. This review provides insight on the sources, mechanisms, prevalence and impact of antibacterial resistance in ACF aquaculture environment, a setting where the impact of AR is neglected or underestimated.

Elastic Bands as a Component of Periodized Resistance Training.

Science.gov (United States)

Joy, Jordan M; Lowery, Ryan P; Oliveira de Souza, Eduardo; Wilson, Jacob M

2016-08-01

Joy, JM, Lowery, RP, Oliveira de Souza, E, and Wilson, JM. Elastic bands as a component of periodized resistance training. J Strength Cond Res 30(8): 2100-2106, 2016-Variable resistance training (VRT) has recently become a component of strength and conditioning programs. Prior research has demonstrated increases in power and/or strength using low loads of variable resistance. However, no study has examined using high loads of variable resistance as a part of a periodized training protocol to examine VRT within the context of a periodized training program and to examine a greater load of variable resistance than has been examined in prior research. Fourteen National Collegiate Athletic Association division II male basketball players were recruited for this study. Athletes were divided equally into either a variable resistance or control group. The variable resistance group added 30% of their 1 repetition maximum (1RM) as band tension to their prescribed weight 1 session per week. Rate of power development (RPD), peak power, strength, body composition, and vertical jump height were measured pretreatment and posttreatment. No baseline differences were observed between groups for any measurement of strength, power, or body composition. A significant group by time interaction was observed for RPD, in which RPD was greater in VRT posttraining than in the control group. Significant time effects were observed for all other variables including squat 1RM, bench press 1RM, deadlift 1RM, clean 3RM, vertical jump, and lean mass. Although there were no significant group ×-time interactions, the VRT group's percent changes and effect sizes indicate a larger treatment effect in the squat and bench press 1RM values and the vertical jump performed on the force plate and vertec. These results suggest that when using variable resistance as a component of a periodized training program, power and strength can be enhanced. Therefore, athletes who add variable resistance to 1 training

Methicillin-resistant Staphylococcus aureus in palliative care: A prospective study of Methicillin-resistant Staphylococcus aureus prevalence in a hospital-based palliative care unit.

Science.gov (United States)

Schmalz, Oliver; Strapatsas, Tobias; Alefelder, Christof; Grebe, Scott Oliver

2016-07-01

Methicillin-resistant Staphylococcus aureus is a common organism in hospitals worldwide and is associated with morbidity and mortality. However, little is known about the prevalence in palliative care patients. Furthermore, there is no standardized screening protocol or treatment for patients for whom therapy concentrates on symptom control. Examining the prevalence of methicillin-resistant Staphylococcus aureus in palliative care patients as well as the level of morbidity and mortality. We performed a prospective study where methicillin-resistant Staphylococcus aureus screening was undertaken in 296 consecutive patients within 48 h after admission to our palliative care unit. Medical history was taken, clinical examination was performed, and the Karnofsky Performance Scale and Palliative Prognostic Score were determined. Prevalence of Methicillin-resistant Staphylococcus aureus was compared to data of general hospital patients. In total, 281 patients were included in the study having a mean age of 69.7 years (standard deviation = 12.9 years) and an average Karnofsky Performance Scale between 30% and 40%. The mean length of stay was 9.7 days (standard deviation = 7.6 days). A total of 24 patients were methicillin-resistant Staphylococcus aureus positive on the first swab. Median number of swabs was 2. All patients with a negative methicillin-resistant Staphylococcus aureus swab upon admission remained Methicillin-resistant Staphylococcus aureus negative in all subsequent swabs. Our study suggests that the prevalence of Methicillin-resistant Staphylococcus aureus among patients in an in-hospital palliative care unit is much higher than in other patient populations. © The Author(s) 2016.

Resistant mechanisms and molecular epidemiology of imipenem-resistant Acinetobacter baumannii.

Science.gov (United States)

Xiao, Shu-Zhen; Chu, Hai-Qing; Han, Li-Zhong; Zhang, Zhe-Min; Li, Bing; Zhao, Lan; Xu, Liyun

2016-09-01

The aim of the study was to investigate the resistant mechanisms and homology of imipenem-resistant Acinetobacter baumannii (A. baumannii). A total of 46 non-duplicate imipenem‑resistant A. baumannii clinical isolates were collected from three tertiary hospitals between July, 2011 and June, 2012. The minimal inhibitory concentrations (MICs) of antimicrobial agents were determined using the agar dilution method. Phenylalanine‑arginine β-naphthylamide was used to detect the presence of the efflux pump-mediated resistant mechanism. Polymerase chain reaction was employed to amplify genes associated with drug resistance, including β‑lactamase genes, efflux pump genes and outer membrane protein gene CarO. A few amplicons were randomly selected and sequenced. Multilocus sequence analysis (MLST) was employed in typing A. baumanni. A. baumannii was resistant to imipenem, simultaneously showing resistance to several other antimicrobials. In addtition, 13 A. baumannii were found to mediate drug resistance through operation of the efflux pump. Of the various drug resistance genes tested, blaOXA‑51 was present in 46 isolates, blaOXA‑23 gene was present in 44 isolates and blaNDM gene was found in only one strain. Other drug resistant‑associated genes, including blaKPC, blaIMP, blaOXA-24, blaOXA‑58, blaSHV, blaGIM and blaVIM were not detected. Mutation of adeS and outer membrane protein gene CarO were found in a few of the imipenem‑resistant isolates. The MLST analysis revealed that all 46 clinical isolates were clustered into 11 genotypes and the most frequent genotype was ST208. In conclusion, β‑lactamase genes, genes involved in efflux pump and mutation of outer membrane protein encoding gene may be important in mediating imipenem resistance in A. baumannii. Of the 11 different genotypes, ST11 was shared by the majority of A. baumannii, which may be due to horizontal transfer of patients from hospitals.

Radial response of a 2-MHz MWD propagation resistivity sensor

International Nuclear Information System (INIS)

Barnett, W.C.; Meyer, W.H.

1991-01-01

This paper reports that electromagnetic propagation resistivity sensors have become common in MWD logging applications. These tools are unique among resistivity sensors in that the depth of investigation of the phase shift and attenuation resistivity measurements varies dramatically with the formation resistivity, measuring deeper into the formation in higher resistivity environments. The fact that the depth of investigation can vary be more than a factor of two across a normal range of formation resistivities requires the log analyst to have an understanding of this phenomenon when performing both qualitative and quantitative interpretations of these logs. Other measurement characteristics such as regions of negative or sharply-rising radial response can produce log responses which may seem peculiar when compared to traditional induction logs or laterlogs

Using a constructive pavement texture index for skid resistance screening

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Chia-Pei Chou

2017-07-01

Full Text Available Skid resistance measurement is one of the major measurements used to assess road safety. Typical devices used for measuring skid resistance include single point checking type and continuous measurements type. However, conducting periodic full roadway network skid resistance survey can be a relatively time consuming and difficult task because of the limited water carrying capacity used by all kinds of devices, including the continuous types. On the contrary, measurement of pavement surface texture can be conducted easily and continuously by most profilers. This research investigates the relation between pavement skid resistance and surface texture. The focus is on the development of a texture index that can serve as a screening indicator to filter out the high-risk pavement sections for further skid resistance measurement. Two measuring devices, GripTester (GT and National Taiwan University laser profiler (NTU Profiler, were used to collect data on pavement skid resistance and texture in a network of 555 sections, respectively. The pavement texture index of the mean difference of elevation (MDE is calculated at a 1 mm profile interval, which is a very promising indicator to represent pavement skid resistance. Through a sensitivity study, the MDE threshold of 0.15 mm is observed to provide a relatively reasonable screening function that filters out 29.01% of the entire surveyed network for further skid resistance inspection. It averted more than 70% skid resistance measurement capacity of the entire network. The accuracy of correct judgment by the selected threshold is about 80%, only 3.78% of roadway sections considered for further inspection of the recommended list are not included. Keywords: Skid resistance, Pavement texture, Macrotexture, Laser profiler, GripTester

Antimicrobial resistance determinant microarray for analysis of multi-drug resistant isolates

Science.gov (United States)

Taitt, Chris Rowe; Leski, Tomasz; Stenger, David; Vora, Gary J.; House, Brent; Nicklasson, Matilda; Pimentel, Guillermo; Zurawski, Daniel V.; Kirkup, Benjamin C.; Craft, David; Waterman, Paige E.; Lesho, Emil P.; Bangurae, Umaru; Ansumana, Rashid

2012-06-01

The prevalence of multidrug-resistant infections in personnel wounded in Iraq and Afghanistan has made it challenging for physicians to choose effective therapeutics in a timely fashion. To address the challenge of identifying the potential for drug resistance, we have developed the Antimicrobial Resistance Determinant Microarray (ARDM) to provide DNAbased analysis for over 250 resistance genes covering 12 classes of antibiotics. Over 70 drug-resistant bacteria from different geographic regions have been analyzed on ARDM, with significant differences in patterns of resistance identified: genes for resistance to sulfonamides, trimethoprim, chloramphenicol, rifampin, and macrolide-lincosamidesulfonamide drugs were more frequently identified in isolates from sources in Iraq/Afghanistan. Of particular concern was the presence of genes responsible for resistance to many of the last-resort antibiotics used to treat war traumaassociated infections.

Epithelial membrane protein-1 is a biomarker of gefitinib resistance.

Science.gov (United States)

Jain, Anjali; Tindell, Charles A; Laux, Isett; Hunter, Jacob B; Curran, John; Galkin, Anna; Afar, Daniel E; Aronson, Nina; Shak, Steven; Natale, Ronald B; Agus, David B

2005-08-16

We describe a molecular resistance biomarker to gefitinib, epithelial membrane protein-1 (EMP-1). Gefitinib is a small-molecule inhibitor that competes for the ATP-binding site on EGF receptor (EGFR) and has been approved for patients with advanced lung cancers. Treatment with gefitinib has resulted in clinical benefit in patients, and, recently, heterozygous somatic mutations within the EGFR catalytic domain have been identified as a clinical correlate to objective response to gefitinib. However, clinical resistance to gefitinib limits the utility of this therapeutic to a fraction of patients, and objective clinical responses are rare. We aimed to assess the molecular phenotype and mechanism of in vivo gefitinib resistance in xenograft models and in patient samples. We generated in vivo gefitinib-resistance models in an adenocarcinoma xenograft model by serially passaging tumors in nude mice in presence of gefitinib until resistance was acquired. EMP-1 was identified as a surface biomarker whose expression correlated with acquisition of gefitinib resistance. EMP-1 expression was further correlated with lack of complete or partial response to gefitinib in lung cancer patient samples as well as clinical progression to secondary gefitinib resistance. EMP-1 expression and acquisition of gefitinib clinical resistance was independent of gefitinib-sensitizing EGFR somatic mutations. This report suggests the role of the adhesion molecule, EMP-1, as a biomarker of gefitinib clinical resistance, and further suggests a probable cross-talk between this molecule and the EGFR signaling pathway.

Chlorination of lignin by ubiquitous fungi has a likely role in global organochlorine production

Science.gov (United States)

Patricia Ortiz-Bermudez; Kolby C. Hirth; Ewald Srebotnik; Kenneth E. Hammel

2007-01-01

Soils and decayed plant litter contain significant quantities of chlorinated aromatic polymers that have a natural but largely unknown origin. We used cupric oxide ligninolysis coupled with gas chromatography/mass spectrometry to show that Curvularia inaequalis, a widely distributed litter ascomycete, chlorinated the aromatic rings of lignin in wood that it was...

Fusarium graminearum and Its Interactions with Cereal Heads: Studies in the Proteomics Era

Science.gov (United States)

Yang, Fen; Jacobsen, Susanne; Jørgensen, Hans J. L.; Collinge, David B.; Svensson, Birte; Finnie, Christine

2013-01-01

The ascomycete fungal pathogen Fusarium graminearum (teleomorph stage: Gibberella zeae) is the causal agent of Fusarium head blight in wheat and barley. This disease leads to significant losses of crop yield, and especially quality through the contamination by diverse fungal mycotoxins, which constitute a significant threat to the health of humans and animals. In recent years, high-throughput proteomics, aiming at identifying a broad spectrum of proteins with a potential role in the pathogenicity and host resistance, has become a very useful tool in plant-fungus interaction research. In this review, we describe the progress in proteomics applications toward a better understanding of F. graminearum pathogenesis, virulence, and host defense mechanisms. The contribution of proteomics to the development of crop protection strategies against this pathogen is also discussed briefly. PMID:23450732

Fusarium graminearum and its interactions with cereal heads: studies in the proteomics era

Directory of Open Access Journals (Sweden)

Fen eYang

2013-02-01

Full Text Available The ascomycete fungal pathogen Fusarium graminearum is the causal agent of Fusarium head blight (FHB in wheat and barley. This disease leads to significant losses of crop yield, and especially quality through the contamination by diverse fungal mycotoxins, which constitute a significant threat to the health of humans and animals. In recent years, high-throughput proteomics, aiming at identifying a broad spectrum of proteins with a potential role in the pathogenicity and host resistance, has become a very useful tool in plant-fungus interaction research. In this review, we describe the progress in proteomics applications towards a better understanding of Fusarium graminearum pathogenesis, virulence and host defence mechanisms. The contribution of proteomics to the development of crop protection strategies against this pathogen is also discussed briefly.

The use of high-throughput sequencing to investigate an outbreak of glycopeptide-resistant Enterococcus faecium with a novel quinupristin-dalfopristin resistance mechanism.

Science.gov (United States)

Shaw, Timothy D; Fairley, D J; Schneiders, T; Pathiraja, M; Hill, R L R; Werner, G; Elborn, J S; McMullan, R

2018-02-24

High-throughput sequencing (HTS) has successfully identified novel resistance genes in enterococci and determined clonal relatedness in outbreak analysis. We report the use of HTS to investigate two concurrent outbreaks of glycopeptide-resistant Enterococcus faecium (GRE) with an uncharacterised resistance mechanism to quinupristin-dalfopristin (QD). Seven QD-resistant and five QD-susceptible GRE isolates from a two-centre outbreak were studied. HTS was performed to identify genes or predicted proteins that were associated with the QD-resistant phenotype. MLST and SNP typing on HTS data was used to determine clonal relatedness. Comparative genomic analysis confirmed this GRE outbreak involved two distinct clones (ST80 and ST192). HTS confirmed the absence of known QD resistance genes, suggesting a novel mechanism was conferring resistance. Genomic analysis identified two significant genetic determinants with explanatory power for the high level of QD resistance in the ST80 QD-resistant clone: an additional 56aa leader sequence at the N-terminus of the lsaE gene and a transposon containing seven genes encoding proteins with possible drug or drug-target modification activities. However, HTS was unable to conclusively determine the QD resistance mechanism and did not reveal any genetic basis for QD resistance in the ST192 clone. This study highlights the usefulness of HTS in deciphering the degree of relatedness in two concurrent GRE outbreaks. Although HTS was able to reveal some genetic candidates for uncharacterised QD resistance, this study demonstrates the limitations of HTS as a tool for identifying putative determinants of resistance to QD.

The Resistome: A Comprehensive Database of Escherichia coli Resistance Phenotypes.

Science.gov (United States)

Winkler, James D; Halweg-Edwards, Andrea L; Erickson, Keesha E; Choudhury, Alaksh; Pines, Gur; Gill, Ryan T

2016-12-16

The microbial ability to resist stressful environmental conditions and chemical inhibitors is of great industrial and medical interest. Much of the data related to mutation-based stress resistance, however, is scattered through the academic literature, making it difficult to apply systematic analyses to this wealth of information. To address this issue, we introduce the Resistome database: a literature-curated collection of Escherichia coli genotypes-phenotypes containing over 5,000 mutants that resist hundreds of compounds and environmental conditions. We use the Resistome to understand our current state of knowledge regarding resistance and to detect potential synergy or antagonism between resistance phenotypes. Our data set represents one of the most comprehensive collections of genomic data related to resistance currently available. Future development will focus on the construction of a combined genomic-transcriptomic-proteomic framework for understanding E. coli's resistance biology. The Resistome can be downloaded at https://bitbucket.org/jdwinkler/resistome_release/overview .

A Structural View on Medicinal Chemistry Strategies against Drug Resistance.

Science.gov (United States)

Agnello, Stefano; Brand, Michael; Chellat, Mathieu F; Gazzola, Silvia; Riedl, Rainer

2018-05-30

The natural phenomenon of drug resistance represents a generic impairment that hampers the benefits of drugs in all major clinical indications. Antibacterials and antifungals are affected as well as compounds for the treatment of cancer, viral infections or parasitic diseases. Despite the very diverse set of biological targets and organisms involved in the development of drug resistance, underlying molecular processes have been identified to understand the emergence of resistance and to overcome this detrimental mechanism. Detailed structural information of the root causes for drug resistance is nowadays frequently available to design next generation drugs anticipated to suffer less from resistance. This knowledge-based approach is a prerequisite in the fight against the inevitable occurrence of drug resistance to secure the achievements of medicinal chemistry in the future. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Antibiotic Resistance

DEFF Research Database (Denmark)

Munck, Christian

morbidity and mortality as well as an increase in the cost of treatment. Understanding how bacteria respond to antibiotic exposure gives the foundations for a rational approach to counteract antimicrobial resistance. In the work presented in this thesis, I explore the two fundamental sources...... of antimicrobial resistance: (1) adaptive mutations and (2) horizontal acquisition of resistance genes from antibiotic gene reservoirs. By studying the geno- and phenotypic changes of E. coli in response to single and drug-pair exposures, I uncover the evolutionary trajectories leading to adaptive resistance. I...... to rationally design drug combinations that limit the evolution of antibiotic resistance due to counteracting evolutionary trajectories. My results highlight that an in-depth knowledge about the genetic responses to the individual antimicrobial compounds enables the prediction of responses to drug combinations...

Resistance and sheet resistance measurements using electron beam induced current

International Nuclear Information System (INIS)

Czerwinski, A.; Pluska, M.; Ratajczak, J.; Szerling, A.; KaPtcki, J.

2006-01-01

A method for measurement of spatially uniform or nonuniform resistance in layers and strips, based on electron beam induced current (EBIC) technique, is described. High electron beam currents are used so that the overall resistance of the measurement circuit affects the EBIC signal. During the evaluation, the electron beam is scanned along the measured object, whose load resistance varies with the distance. The variation is compensated by an adjustable resistance within an external circuit. The method has been experimentally deployed for sheet resistance determination of buried regions of lateral confinements in semiconductor laser heterostructures manufactured by molecular beam epitaxy

A Fully Transparent Resistive Memory for Harsh Environments

KAUST Repository

Yang, Po-Kang; Ho, Chih-Hsiang; Lien, Der-Hsien; Duran Retamal, Jose Ramon; Kang, Chen-Fang; Chen, Kuan-Ming; Huang, Teng-Han; Yu, Yueh-Chung; Wu, Chih-I; He, Jr-Hau

2015-01-01

A fully transparent resistive memory (TRRAM) based on Hafnium oxide (HfO2) with excellent transparency, resistive switching capability, and environmental stability is demonstrated. The retention time measured at 85 °C is over 3 × 104 sec

Embedded Artificial Neuval Network-Based Real-Time Half-Wave Dynamic Resistance Estimation during the A.C. Resistance Spot Welding Process

Directory of Open Access Journals (Sweden)

Liang Gong

2013-01-01

Full Text Available Online monitoring of the instantaneous resistance variation during the A.C. resistance spot welding is of paramount importance for the weld quality control. On the basis of the welding transformer circuit model, a new method is proposed to measure the transformer primary-side signal for estimating the secondary-side resistance in each 1/4 cycle. The tailored computing system ensures that the measuring method possesses a real-time computational capacity with satisfying accuracy. Since the dynamic resistance cannot be represented via an explicit function with respect to measurable parameters from the primary side of the welding transformer, an offline trained embedded artificial neural network (ANN successfully realizes the real-time implicit function calculation or estimation. A DSP-based resistance spot welding monitoring system is developed to perform ANN computation. Experimental results indicate that the proposed method is applicable for measuring the dynamic resistance in single-phase, half-wave controlled rectifier circuits.

Development of a Midscale Test for Flame Resistant Protection

Science.gov (United States)

2016-08-01

Evaluation of Flame Resistant Clothing for Protection against Fire Simulations Using an Instrumented Manikin, which provides both radiant and convective heat...TEST METHODS FIRE RESISTANT MATERIALS TORCHES SIMULATION TEST EQUIPMENT FLAME RESISTANT CLOTHING PERFORMANCE(ENGINEERING... fabric during a fire , and even after the fire has been extinguished. The best known full scale transmitted heat flux test is the "ASTM F1930

A study on hypophosphatemic vitamin D resistant rickets in a family

Energy Technology Data Exchange (ETDEWEB)

Chung, Doo Young; Byon, Joo Nam; Suh, Chee Jang; Won, Jong Jin [Won Kwang University School of Medicine, Seoul (Korea, Republic of)

1984-09-15

Hypophosphatemic vitamin D resistant rickets is a form of rickets characterized by typical structural deformities and roentgenographic and metabolic changes. It has a strong familiar tendency and appear to genetically transmitted. Authors experienced 7 patients with hypophoshatemic vitamin D resistant rickets which have been manifested through three generation in a family at Won Kwang University Hospital from December 1982 to May 1984. Authors studied hypophoshatemic vitamin D resistant rickets clinically, radiologically, biochemically and pathologically, and reported with review of literatures.

Glucocorticoid resistance as a major drive in sepsis pathology.

Science.gov (United States)

Dendoncker, Karen; Libert, Claude

2017-06-01

Sepsis is an acute systemic inflammatory disease. Glucocorticoids (GCs), which function by binding to the GC receptor GR have very powerful anti-inflammatory activities, yet they are hardly useful in sepsis. We can thus consider sepsis as a GC resistant disease. We here review the literature which has investigated this GC resistance, and summarize the mechanisms of GC resistance that have been observed in other diseases and in experimental models. We also discuss the importance of GC resistance in sepsis, in terms of the contribution of this phenomenon to the pathogenesis of sepsis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Multidrug-Resistant Candida

DEFF Research Database (Denmark)

Arendrup, Maiken Cavling; Patterson, Thomas F

2017-01-01

Invasive Candida infections remain an important cause of morbidity and mortality, especially in hospitalized and immunocompromised or critically ill patients. A limited number of antifungal agents from only a few drug classes are available to treat patients with these serious infections. Resistance...... can be either intrinsic or acquired. Resistance mechanisms are not exchanged between Candida; thus, acquired resistance either emerges in response to an antifungal selection pressure in the individual patient or, more rarely, occur due to horizontal transmission of resistant strains between patients....... Although multidrug resistance is uncommon, increasing reports of multidrug resistance to the azoles, echinocandins, and polyenes have occurred in several Candida species, most notably Candida glabrata and more recently Candida auris. Drivers are overall antifungal use, subtherapeutic drug levels at sites...

Evaluation of prevalence of low and high level mupirocin resistance in methicillin resistant staphylococcus aureus isolates at a tertiary care hospital

International Nuclear Information System (INIS)

Nizamuddin, S.; Irfan, S.; Zafar, A.

2011-01-01

To evaluate the trend of mupirocin resistance in MRSA, isolated at the Clinical Microbiology Laboratory of a tertiary care hospital. Methods: A total of 200 MRSA strains recovered over a 2 year period from various body sites were tested using the 5 and 200 mu g discs of mupirocin to detect its resistance. Results: High level and low level mupirocin resistance were detected in zero and 1 % of MRSA strains, respectively. Resistance to other non beta lactam antibiotics was also high. No MRSA strains were found to be resistant to vancomycin and tegicycline. Conclusion: Mupirocin resistance was found to be very low among local clinical isolates of MRSA. Its judicious use to decolonize nasal carriers should be promoted among hospitalized patients to avoid further transmission and infections due to prevalent endemic MRSA strains in any health care setting. Concomitantly, regular surveillance and effective infection control initiatives are desirable to reduce the incidence of health care associated infections due to MRSA and also of mupirocin resistance. (author)

High chlorpyrifos resistance in Culex pipiens mosquitoes: strong synergy between resistance genes

Science.gov (United States)

Alout, H; Labbé, P; Berthomieu, A; Makoundou, P; Fort, P; Pasteur, N; Weill, M

2016-01-01

We investigated the genetic determinism of high chlorpyrifos resistance (HCR), a phenotype first described in 1999 in Culex pipiens mosquitoes surviving chlorpyrifos doses ⩾1 mg l−1 and more recently found in field samples from Tunisia, Israel or Indian Ocean islands. Through chlorpyrifos selection, we selected several HCR strains that displayed over 10 000-fold resistance. All strains were homozygous for resistant alleles at two main loci: the ace-1 gene, with the resistant ace-1R allele expressing the insensitive G119S acetylcholinesterase, and a resistant allele of an unknown gene (named T) linked to the sex and ace-2 genes. We constructed a strain carrying only the T-resistant allele and studied its resistance characteristics. By crossing this strain with strains harboring different alleles at the ace-1 locus, we showed that the resistant ace-1R and the T alleles act in strong synergy, as they elicited a resistance 100 times higher than expected from a simple multiplicative effect. This effect was specific to chlorpyrifos and parathion and was not affected by synergists. We also examined how HCR was expressed in strains carrying other ace-1-resistant alleles, such as ace-1V or the duplicated ace-1D allele, currently spreading worldwide. We identified two major parameters that influenced the level of resistance: the number and the nature of the ace-1-resistant alleles and the number of T alleles. Our data fit a model that predicts that the T allele acts by decreasing chlorpyrifos concentration in the compartment targeted in insects. PMID:26463842

Adriamycin resistance, heat resistance and radiation response in Chinese hamster fibroblasts

International Nuclear Information System (INIS)

Wallner, K.; Li, G.

1985-01-01

Previous investigators have demonstrated synergistic interaction between hyperthermia and radiation or Adriamycin (ADR), using cell lines that are sensitive to heat or ADR alone. The authors investigated the effect of heat, radiation or ADR on Chinese hamster fibroblasts (HA-1), their heat resistant variants and their ADR resistant variants. Heat for ADR resistance did not confer cross resistance to radiation. Cells resistant to heat did show cross resistance to ADR. While cells selected for ADR resistance were not cross resistant to heat, they did not exhibit drug potentiation by hyperthermia, characteristic of ADR sensitive cells. Cytofluorometric measurement showed decreased ADR uptake in both heat and ADR resistant cells. The possibility of cross resistance between heat and ADR should be considered when designing combined modality trials

Relaxation resistance of heat resisting alloys with cobalt

International Nuclear Information System (INIS)

Borzdyka, A.M.

1977-01-01

Relaxation resistance of refractory nickel-chromium alloys containing 5 to 14 % cobalt is under study. The tests involve the use of circular samples at 800 deg to 850 deg C. It is shown that an alloy containing 14% cobalt possesses the best relaxation resistance exceeding that of nickel-chromium alloys without any cobalt by a factor of 1.5 to 2. The relaxation resistance of an alloy with 5% cobalt can be increased by hardening at repeated loading

Using data on resistance prevalence per sample in the surveillance of antimicrobial resistance

DEFF Research Database (Denmark)

Vieira, Antonio; Shuyu, Wu; Jensen, Lars Bogø

2008-01-01

Objectives: In most existing antimicrobial resistance monitoring programmes, one single bacterial colony from each collected sample is susceptibility tested against a panel of antimicrobials. Detecting the proportion of colonies resistant to different antimicrobials in each sample can provide...... quantitative data on antimicrobial resistance (resistance prevalence per sample). Methods: In this study, a total of 98 faecal samples from slaughter pigs were tested for tetracycline and sulphonamide resistance in Escherichia coli using the single colony method, and these results were compared...... with the results obtained using the resistance prevalence per sample method. Results: The results obtained by the resistance prevalence per sample method showed a lower occurrence of resistance. Tetracycline resistance in E. coli was found in 36.7% of the samples using the single colony method, while the mean...

Resisting Organizational Change

OpenAIRE

Andersson, Gunnar

2015-01-01

We are continuously reminded of how change induces controversy and resistance, regardless of support. We repeatedly experience resistance in difficulties of implementation, little progress, and poor results, rather than increased productivity as anticipated. In a detailed account of how change plays out, a mosaic of what resistance looks like emerges. The picture is both familiar and absolutely concrete, and challenges the structural assumptions and dichotomies on support and resistance in an...

Comparative mapping of Phytophthora resistance loci in pepper germplasm: evidence for conserved resistance loci across Solanaceae and for a large genetic diversity.

Science.gov (United States)

Thabuis, A; Palloix, A; Pflieger, S; Daubèze, A-M; Caranta, C; Lefebvre, V

2003-05-01

Phytophthora capsici Leonian, known as the causal agent of the stem, collar and root rot, is one of the most serious problems limiting the pepper crop in many areas in the world. Genetic resistance to the parasite displays complex inheritance. Quantitative trait locus (QTL) analysis was performed in three intraspecific pepper populations, each involving an unrelated resistant accession. Resistance was evaluated by artificial inoculations of roots and stems, allowing the measurement of four components involved in different steps of the plant-pathogen interaction. The three genetic maps were aligned using common markers, which enabled the detection of QTLs involved in each resistance component and the comparison of resistance factors existing among the three resistant accessions. The major resistance factor was found to be common to the three populations. Another resistance factor was found conserved between two populations, the others being specific to a single cross. This comparison across intraspecific germplasm revealed a large variability for quantitative resistance loci to P. capsici. It also provided insights both into the allelic relationships between QTLs across pepper germplasm and for the comparative mapping of resistance factors across the Solanaceae.

Detection of resistance, cross-resistance, and stability of resistance to new chemistry insecticides in Bemisia tabaci (Homoptera: Aleyrodidae).

Science.gov (United States)

Basit, Muhammad; Saeed, Shafqat; Saleem, Mushtaq Ahmad; Denholm, Ian; Shah, Maqbool

2013-06-01

Resistance levels in whitefly, Bemisia tabaci (Gennadius) collections from cotton and sunflower (up to four districts) for five neonicotinoids and two insect growth regulators (IGRs) were investigated for two consecutive years. Based on the LC50(s), all collections showed slight to moderate levels of resistance for the tested insecticides compared with the laboratory susceptible population. The data also indicated that cotton and sunflower collections had similar resistance levels. In comparison (four collections), Vehari collections showed higher resistance for acetamiprid, thiacloprid, and nitenpyram compared with those of others. Average resistance ratios for acetamiprid, thiacloprid, and nitenpyram ranged from 5- to 13-, 4- to 8-, and 9- to 13-fold, respectively. Multan and Vehari collections also exhibited moderate levels (9- to 16-fold) of resistance to buprofezin. Furthermore, toxicity of neonicotinoids against immature stages was equal to that of insect growth regulators. The data also suggested that resistance in the field populations was stable. After selection for four generations with bifenthrin (G1 to G4), resistance to bifenthrin increased to 14-fold compared with the laboratory susceptible population. Selection also increased resistance to fenpropathrin, lambdacyhalothrin, imidacloprid, acetamiprid, and diafenthuron. Cross-resistance and stability of resistance in the field populations is of some concern. Rotation of insecticides having no cross-resistance and targeting the control against immature stages may control the resistant insects, simultaneously reducing the selection pressure imposed.

Phenotypic- and Genotypic-Resistance Detection for Adaptive Resistance Management in Tetranychus urticae Koch.

Directory of Open Access Journals (Sweden)

Deok Ho Kwon

Full Text Available Rapid resistance detection is necessary for the adaptive management of acaricide-resistant populations of Tetranychus urticae. Detection of phenotypic and genotypic resistance was conducted by employing residual contact vial bioassay (RCV and quantitative sequencing (QS methods, respectively. RCV was useful for detecting the acaricide resistance levels of T. urticae, particularly for on-site resistance detection; however, it was only applicable for rapid-acting acaricides (12 out of 19 tested acaricides. QS was effective for determining the frequencies of resistance alleles on a population basis, which corresponded to 12 nonsynonymous point mutations associated with target-site resistance to five types of acaricides [organophosphates (monocrotophos, pirimiphos-methyl, dimethoate and chlorpyrifos, pyrethroids (fenpropathrin and bifenthrin, abamectin, bifenazate and etoxazole]. Most field-collected mites exhibited high levels of multiple resistance, as determined by RCV and QS data, suggesting the seriousness of their current acaricide resistance status in rose cultivation areas in Korea. The correlation analyses revealed moderate to high levels of positive relationships between the resistance allele frequencies and the actual resistance levels in only five of the acaricides evaluated, which limits the general application of allele frequency as a direct indicator for estimating actual resistance levels. Nevertheless, the resistance allele frequency data alone allowed for the evaluation of the genetic resistance potential and background of test mite populations. The combined use of RCV and QS provides basic information on resistance levels, which is essential for choosing appropriate acaricides for the management of resistant T. urticae.

[Isolation of a carbapenem-resistant K1 serotype Klebsiella pneumonia strain and the study of resistance mechanism].

Science.gov (United States)

Zhang, Rong; Wang, Xuan; Lü, Jianxin

2014-12-16

To study the virulence and mechanism of carbapenem resistance of a clinical isolate of carbapenem-resistant K1 serotype Klebsiella pneumonia strain. Identification of isolate was carried out with VITEK-2 compact system. Antimicrobial susceptibility was determined by E-test; Metallo β-lactamases and carbapenemases screening were conducted by imipenem-EDTA double disc synergy test and modified Hodge test, respectively.Specific polymerehse chain reaction (PCR) and DNA sequencing were preformed to detect the virulence genes including K1, K2, K5, K20, K54, K57, magA, rmpA, wcaG and a series of β-lactamase resistence genes. Conjunction experiment was also performed. The plasmids of transconjugants were submitted to PCR-based replicon typing (PBRT) method. Molecular typing was performed by multilocus sequence typing (MLST). Antimicrobial susceptibility testing revealed that the Klebsiella pneumonia strain was resistant to most of the antibiotics used in clinic. Phynotype confirmary rest revealed the production of carbapanemases, while Metallo β-lactamases were negative; PCR and DNA sequencing confirmed the isolate was positive for blaKPC-2, blaCTX-M-15, blaTEM-1, blaSHV-1 and virulence genes K1, magA, rmpA, wcaG simultaneously; blaKPC-2 was transferred from donor to Escherichia EC600 by conjunction experiment, while no virulence genes were found in the transconjugants. PBRT revealed that Frep plasmid was found in transconjugants. MLST analysis revealed that this strain belonged to ST23. K1 serotype Klebsiella pneumonia strain carries virulence genes and carbapenem resistance gene blaKPC-2, noteworthily the carbapenem resistance genes can be transferred through horizontal transmission on plasmids.

Antibiotic resistant enterococci—Tales of a drug resistance gene trafficker

DEFF Research Database (Denmark)

Werner, Guido; Coque, Teresa M.; Franz, Charles M.A.P.

2013-01-01

Enterococci have been recognized as important hospital-acquired pathogens in recent years, and isolates of E. faecalis and E. faecium are the third- to fourth-most prevalent nosocomial pathogen worldwide. Acquired resistances, especially against penicilin/ampicillin, aminoglycosides (high-level) ...

HIV Resistance Testing

Science.gov (United States)

... 14, 2016 Select a Language: Fact Sheet 126 HIV Resistance Testing WHAT IS RESISTANCE? HOW DOES RESISTANCE ... ARVs. If you miss doses of your medications, HIV will multiply more easily. More mutations will occur. ...

Rationale and uses of a public HIV drug-resistance database.

Science.gov (United States)

Shafer, Robert W

2006-09-15

Knowledge regarding the drug resistance of human immunodeficiency virus (HIV) is critical for surveillance of drug resistance, development of antiretroviral drugs, and management of infections with drug-resistant viruses. Such knowledge is derived from studies that correlate genetic variation in the targets of therapy with the antiretroviral treatments received by persons from whom the variant was obtained (genotype-treatment), with drug-susceptibility data on genetic variants (genotype-phenotype), and with virological and clinical response to a new treatment regimen (genotype-outcome). An HIV drug-resistance database is required to represent, store, and analyze the diverse forms of data underlying our knowledge of drug resistance and to make these data available to the broad community of researchers studying drug resistance in HIV and clinicians using HIV drug-resistance tests. Such genotype-treatment, genotype-phenotype, and genotype-outcome correlations are contained in the Stanford HIV RT and Protease Sequence Database and have specific usefulness.

Resistance and resilience: A conceptual framework for silviculture

Science.gov (United States)

Robert J. DeRose; James N. Long

2014-01-01

Increasingly, forest management goals include building or maintaining resistance and/or resilience to disturbances in the face of climate change. Although a multitude of descriptive definitions for resistance and resilience exist, to evaluate whether specific management activities (silviculture) are effective, prescriptive characterizations are necessary. We introduce...

A novel resistance gene, lnu(H), conferring resistance to lincosamides in Riemerella anatipestifer CH-2.

Science.gov (United States)

Luo, Hong-Yan; Liu, Ma-Feng; Wang, Ming-Shu; Zhao, Xin-Xin; Jia, Ren-Yong; Chen, Shun; Sun, Kun-Feng; Yang, Qiao; Wu, Ying; Chen, Xiao-Yue; Biville, Francis; Zou, Yuan-Feng; Jing, Bo; Cheng, An-Chun; Zhu, De-Kang

2018-01-01

The Gram-negative bacterium Riemerella anatipestifer CH-2 is resistant to lincosamides, having a lincomycin (LCM) minimum inhibitory concentration (MIC) of 128 µg/mL. The G148_1775 gene of R. anatipestifer CH-2, designated lnu(H), encodes a 260-amino acid protein with ≤41% identity to other reported lincosamide nucleotidylyltransferases. Escherichia coli Rosetta TM (DE3) containing the pBAD24-lnu(H) plasmid showed four- and two-fold increases in the MICs of LCM and clindamycin (CLI), respectively. A kinetic assay of the purified Lnu(H) enzyme for LCM and CLI showed that the protein could inactive lincosamides. Mass spectrometry analysis demonstrated that the Lnu(H) enzyme catalysed adenylylation of lincosamides. In addition, an lnu(H) gene deletion strain exhibited 512- and 32-fold decreases in LCM and CLI MICs, respectively. The wild-type level of lincosamide resistance could be restored by complementation with a shuttle plasmid carrying the lnu(H) gene. The transformant R. anatipestifer ATCC 11845 [lnu(H)] acquired by natural transformation also exhibited high-level lincosamide resistance. Moreover, among 175 R. anatipestifer field isolates, 56 (32.0%) were positive for the lnu(H) gene by PCR. In conclusion, Lnu(H) is a novel lincosamide nucleotidylyltransferase that inactivates LCM and CLI by nucleotidylylation, thus conferring high-level lincosamide resistance to R. anatipestifer CH-2. Copyright © 2017. Published by Elsevier B.V.

Occurrence of integrons and resistance genes among sulphonamide-resistant Shigella spp. from Brazil

DEFF Research Database (Denmark)

Peirano, G.; Agersø, Yvonne; Aarestrup, Frank Møller

2005-01-01

Objectives: To determine the occurrence of class 1 and 2 integrons and antimicrobial resistance genes among sulphonamide-resistant Shigella strains isolated in Brazil during 1999-2003. Methods: Sixty-two Shigella (Shigella flexneri, n = 47 and Shigella sonnei, n = 15) were tested against 21...... antimicrobial agents. The presence of integrons classes 1 and 2 and antimicrobial resistance genes was investigated by PCR using specific primers. Results: A total of eight antimicrobial resistance profiles were identified, with the profile of resistance to sulfamethoxazole, trimethoprim, spectinomycin...... of 2214 bp harbouring a gene cassette array conferring resistance to trimethoprim, streptothricin and spectinomycin/streptomycin. The genes coding for resistance to chloramphenicol (catA1), tetracycline [tet(A) and tet(B)] and ampicillin (bla(OXA) and bla(TEM)), were detected in resistant strains...

Multidrug-resistant Gram-negative bacteria: a product of globalization.

Science.gov (United States)

Hawkey, P M

2015-04-01

Global trade and mobility of people has increased rapidly over the last 20 years. This has had profound consequences for the evolution and the movement of antibiotic resistance genes. There is increasing exposure of populations all around the world to resistant bacteria arising in the emerging economies. Arguably the most important development of the last two decades in the field of antibiotic resistance is the emergence and spread of extended-spectrum β-lactamases (ESBLs) of the CTX-M group. A consequence of the very high rates of ESBL production among Enterobacteriaceae in Asian countries is that there is a substantial use of carbapenem antibiotics, resulting in the emergence of plasmid-mediated resistance to carbapenems. This article reviews the emergence and spread of multidrug-resistant Gram-negative bacteria, focuses on three particular carbapenemases--imipenem carbapenemases, Klebsiella pneumoniae carbapenemase, and New Delhi metallo-β-lactamase--and highlights the importance of control of antibiotic use. Copyright © 2015. Published by Elsevier Ltd.

Public transport as a reservoir of methicillin-resistant staphylococci.

Science.gov (United States)

Stepanović, S; Cirković, I; Djukić, S; Vuković, D; Svabić-Vlahović, M

2008-10-01

The aim of this study was to explore the occurrence of methicillin-resistant staphylococci in a large urban public transport system. Samples were taken from hand rails, which passengers hold onto when they are standing. In total, 1400 swabs taken from 55 vehicles (trolleybuses, trams and buses) were examined. As many as 30.1% samples were positive for the presence of methicillin-resistant coagulase-negative staphylococci (MRCoNS), but none for methicillin-resistant Staphylococcus aureus (MRSA). MRCoNS were isolated from all 55 vehicles. Nearly 50% of MRCoNS isolates displayed resistance not only to beta-lactams, but at least to two or more other classes of antimicrobials as well. This study demonstrated widespread occurrence of MRCoNS on hand rails in public transport vehicles. MRSA was not detected. The recovery of methicillin-resistant staphylococci from public transport system implies a potential risk for transmission of these bacteria in an out-hospital environment.

Identification of a New Antimicrobial Resistance Gene Provides Fresh Insights Into Pleuromutilin Resistance in Brachyspira hyodysenteriae, Aetiological Agent of Swine Dysentery

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Roderick M. Card

2018-06-01

Full Text Available Brachyspira hyodysenteriae is the aetiological agent of swine dysentery, a globally distributed disease that causes profound economic loss, impedes the free trade and movement of animals, and has significant impact on pig health. Infection is generally treated with antibiotics of which pleuromutilins, such as tiamulin, are widely used for this purpose, but reports of resistance worldwide threaten continued effective control. In Brachyspira hyodysenteriae pleuromutilin resistance has been associated with mutations in chromosomal genes encoding ribosome-associated functions, however the dynamics of resistance acquisition are poorly understood, compromising stewardship efforts to preserve pleuromutilin effectiveness. In this study we undertook whole genome sequencing (WGS and phenotypic susceptibility testing of 34 UK field isolates and 3 control strains to investigate pleuromutilin resistance in Brachyspira hyodysenteriae. Genome-wide association studies identified a new pleuromutilin resistance gene, tva(A (tiamulin valnemulin antibiotic resistance, encoding a predicted ABC-F transporter. In vitro culture of isolates in the presence of inhibitory or sub-inhibitory concentrations of tiamulin showed that tva(A confers reduced pleuromutilin susceptibility that does not lead to clinical resistance but facilitates the development of higher-level resistance via mutations in genes encoding ribosome-associated functions. Genome sequencing of antibiotic-exposed isolates identified both new and previously described mutations in chromosomal genes associated with reduced pleuromutilin susceptibility, including the 23S rRNA gene and rplC, which encodes the L3 ribosomal protein. Interesting three antibiotic-exposed isolates harboured mutations in fusA, encoding Elongation Factor G, a gene not previously associated with pleuromutilin resistance. A longitudinal molecular epidemiological examination of two episodes of swine dysentery at the same farm indicated

Prevalence of antimicrobial resistance and the cfiA resistance gene in Danish Bacteroides fragilis group isolates since 1973

DEFF Research Database (Denmark)

Ferløv-Schwensen, Simon Andreas; Sydenham, Thomas Vognbjerg; Hansen, Kia Cirkeline Møller

2017-01-01

Desorption/Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF MS) on the Biotyper platform. Antimicrobial resistance was determined using a disk diffusion screening method and commercial antibiotic gradient strips. Division I (cfiA-negative) and division II (cfiA-positive) B. fragilis strains were...... differentiated using MALDI-TOF MS and real-time polymerase chain reaction (PCR). RESULTS: From 1973-1980 to 2010-2015 the prevalence of antimicrobial resistance rose from 0% to 21.2%, 2.5%, and 1% for clindamycin, meropenem, and metronidazole, respectively. MALDI-TOF MS and real-time PCR identified 16 of 266 (6...... established in the recent decades in Europe. Resistance to meropenem, facilitated by expression of the cfiA resistance gene, seems to be increasing; therefore, it is imperative to monitor the occurrence of this gene, e.g. using MALDI-TOF MS....

Antimicrobial-Resistant Enterococci in Animals and Meat: A Human Health Hazard?

DEFF Research Database (Denmark)

Hammerum, A.M.; Lester, C.H.; Heuer, Ole Eske

2010-01-01

clones predominate in certain animal species. This may suggest that antimicrobial-resistant E. faecium from animals could be regarded less hazardous to humans; however, due to their excellent ability to acquire and transfer resistance genes, E. faecium of animal origin may act as donors of antimicrobial...... resistance genes for other more virulent enterococci. For E. faecalis, the situation appears different, as similar clones of, for example, vancomycin-and gentamicin-resistant E. faecalis have been obtained from animals and from human patients. Continuous surveillance of antimicrobial resistance...... of avoparcin, gentamicin, and virginiamycin for growth promotion and therapy in food animals has lead to the emergence of vancomycin-and gentamicin-resistant enterococci and quinupristin/dalfopristin-resistant E. faecium in animals and meat. This implies a potential risk for transfer of resistance genes...

Radiation resistance of clinical Acinetobacter spp.: A need for concern

International Nuclear Information System (INIS)

Christensen, E.A.; Gerner-Smidt, P.; Kristensen, H.

1991-01-01

As part of an epidemiological investigation of hospital infections caused by Acinetobacter spp. the radiation resistance of 15 clinical isolates and four reference strains was assessed. The radiation resistance (in D-6 values, viz. the dose necessary for reducing the initial number of colony forming units by a factor of 10(6)) was, in general, higher in the isolates of A. radioresistens than in the isolates of the A. calcoaceticus-A. baumannii complex and of A. lwoffi. However, the least resistant isolates of A. radioresistens had a D-6 value equal to or lower than the most resistant isolates of the other groups. The lowest D-6 values found were for two of the reference strains. The highest D-6 value was 35 kGy. Three isolates of A. johnsonii could not survive long enough in a dried preparation to make an assessment of the D-6 values possible. The radiation resistance of the 15 clinical isolates in the present study was higher than the resistance found in a study of similar isolates in 1970

Radiation resistance of clinical Acinetobacter spp. : A need for concern

Energy Technology Data Exchange (ETDEWEB)

Christensen, E.A.; Gerner-Smidt, P.; Kristensen, H. (Control Department, Statens Seruminstitut, Copenhagen (Denmark))

1991-06-01

As part of an epidemiological investigation of hospital infections caused by Acinetobacter spp. the radiation resistance of 15 clinical isolates and four reference strains was assessed. The radiation resistance (in D-6 values, viz. the dose necessary for reducing the initial number of colony forming units by a factor of 10(6)) was, in general, higher in the isolates of A. radioresistens than in the isolates of the A. calcoaceticus-A. baumannii complex and of A. lwoffi. However, the least resistant isolates of A. radioresistens had a D-6 value equal to or lower than the most resistant isolates of the other groups. The lowest D-6 values found were for two of the reference strains. The highest D-6 value was 35 kGy. Three isolates of A. johnsonii could not survive long enough in a dried preparation to make an assessment of the D-6 values possible. The radiation resistance of the 15 clinical isolates in the present study was higher than the resistance found in a study of similar isolates in 1970.

Rapid report acetamiprid resistance and cross-resistance in the diamondback moth, Plutella xylostella.

Science.gov (United States)

Ninsin, Kodwo D

2004-09-01

A 110-fold acetamiprid-resistant Plutella xylostella (L) strain was established after four selection experiments (in five generations) on a 9.5-fold resistant colony in the laboratory. The resistant strain did not show cross-resistance to chlorfluazuron or Bacillus thuringiensis subsp kurstaki Berliner, but displayed low resistance to cartap and phenthoate.

Cross-Resistance: A Consequence of Bi-partite Host-Parasite Coevolution

Science.gov (United States)

Joop, Gerrit

2018-01-01

Host-parasite coevolution can influence interactions of the host and parasite with the wider ecological community. One way that this may manifest is in cross-resistance towards other parasites, which has been observed to occur in some host-parasite evolution experiments. In this paper, we test for cross-resistance towards Bacillus thuringiensis and Pseudomonas entomophila in the red flour beetle Tribolium castaneum, which was previously allowed to coevolve with the generalist entomopathogenic fungus Beauveria bassiana. We combine survival and gene expression assays upon infection to test for cross-resistance and underlying mechanisms. We show that larvae of T. castaneum that evolved with B. bassiana under coevolutionary conditions were positively cross-resistant to the bacterium B. thuringiensis, but not P. entomophila. Positive cross-resistance was mirrored at the gene expression level with markers that were representative of the oral route of infection being upregulated upon B. bassiana exposure. We find that positive cross-resistance towards B. thuringiensis evolved in T. castaneum as a consequence of its coevolutionary interactions with B. bassiana. This cross-resistance appears to be a consequence of resistance to oral toxicity. The fact that coevolution with B. bassiana results in resistance to B. thuringiensis, but not P. entomophila implies that B. thuringiensis and B. bassiana may share mechanisms of infection or toxicity not shared by P. entomophila. This supports previous suggestions that B. bassiana may possess Cry-like toxins, similar to those found in B. thuringiensis, which allow it to infect orally. PMID:29495405

Cross-Resistance: A Consequence of Bi-partite Host-Parasite Coevolution

Directory of Open Access Journals (Sweden)

Tilottama Biswas

2018-02-01

Full Text Available Host-parasite coevolution can influence interactions of the host and parasite with the wider ecological community. One way that this may manifest is in cross-resistance towards other parasites, which has been observed to occur in some host-parasite evolution experiments. In this paper, we test for cross-resistance towards Bacillus thuringiensis and Pseudomonas entomophila in the red flour beetle Tribolium castaneum, which was previously allowed to coevolve with the generalist entomopathogenic fungus Beauveria bassiana. We combine survival and gene expression assays upon infection to test for cross-resistance and underlying mechanisms. We show that larvae of T. castaneum that evolved with B. bassiana under coevolutionary conditions were positively cross-resistant to the bacterium B. thuringiensis, but not P. entomophila. Positive cross-resistance was mirrored at the gene expression level with markers that were representative of the oral route of infection being upregulated upon B. bassiana exposure. We find that positive cross-resistance towards B. thuringiensis evolved in T. castaneum as a consequence of its coevolutionary interactions with B. bassiana. This cross-resistance appears to be a consequence of resistance to oral toxicity. The fact that coevolution with B. bassiana results in resistance to B. thuringiensis, but not P. entomophila implies that B. thuringiensis and B. bassiana may share mechanisms of infection or toxicity not shared by P. entomophila. This supports previous suggestions that B. bassiana may possess Cry-like toxins, similar to those found in B. thuringiensis, which allow it to infect orally.

Type 2 diabetes mellitus as a disorder of galanin resistance.

Science.gov (United States)

Fang, Penghua; Shi, Mingyi; Zhu, Yan; Bo, Ping; Zhang, Zhenwen

2016-01-01

The increasing prevalence of type 2 diabetes mellitus with its high morbidity and mortality becomes an important health problem. The multifactorial etiology of type 2 diabetes mellitus is relative to many gene and molecule alterations, and increased insulin resistance. Besides these, however, there are still other predisposing and risk factors accounting for type 2 diabetes mellitus not to be identified and recognized. Emerging evidence indicated that defects in galanin function played a crucial role in development of type 2 diabetes mellitus. Galanin homeostasis is tightly relative to insulin resistance and is regulated by blood glucose. Hyperglycemia, hyperinsulinism, enhanced plasma galanin levels and decreased galanin receptor activities are some of the characters of type 2 diabetes mellitus. The discrepancy between high insulin level and low glucose handling is named as insulin resistance. Similarly, the discrepancy between high galanin level and low glucose handling may be denominated as galanin resistance too. In this review, the characteristic milestones of type 2 diabetes mellitus were condensed as two analogical conceptual models, obesity-hyper-insulin-insulin resistance-type 2 diabetes mellitus and obesity-hyper-galanin-galanin resistance-type 2 diabetes mellitus. Both galanin resistance and insulin resistance are correlative with each other. Conceptualizing the etiology of type 2 diabetes mellitus as a disorder of galanin resistance may inspire a new concept to deepen our knowledge about pathogenesis of type 2 diabetes mellitus, eventually leading to novel preventive and therapeutic interventions for type 2 diabetes mellitus. Copyright © 2015 Elsevier Inc. All rights reserved.

Resistant and Refractory Hypertension: Antihypertensive Treatment Resistance vs Treatment Failure

Science.gov (United States)

Siddiqui, Mohammed; Dudenbostel, Tanja; Calhoun, David A.

2017-01-01

Resistant or difficult to treat hypertension is defined as high blood pressure that remains uncontrolled with 3 or more different antihypertensive medications, including a diuretic. Recent definitions also include controlled blood pressure with use of 4 or more medications as also being resistant to treatment. Recently, refractory hypertension, an extreme phenotype of antihypertensive treatment failure has been defined as hypertension uncontrolled with use of 5 or more antihypertensive agents, including a long-acting thiazide diuretic and a mineralocorticoid receptor antagonist. Patients with resistant vs refractory hypertension share similar characteristics and comorbidities, including obesity, African American race, female sex, diabetes, coronary heart disease, chronic kidney disease, and obstructive sleep apnea. Patients with refractory vs resistant hypertension tend to be younger and are more likely to have been diagnosed with congestive heart failure. Refractory hypertension might also differ from resistant hypertension in terms of underlying cause. Preliminary evidence suggests that refractory hypertension is more likely to be neurogenic in etiology (ie, heightened sympathetic tone), vs a volume-dependent hypertension that is more characteristic of resistant hypertension in general. PMID:26514749

A Dinitroaniline-Resistant Mutant of Eleusine indica Exhibits Cross-Resistance and Supersensitivity to Antimicrotubule Herbicides and Drugs.

Science.gov (United States)

Vaughn, K C; Marks, M D; Weeks, D P

1987-04-01

A dinitroaniline-resistant (R) biotype of Eleusine indica (L.) Gaertner. (goosegrass) is demonstrated to be cross-resistant to a structurally non-related herbicide, amiprophosmethyl, and supersensitive to two other classes of compounds which disrupt mitosis. These characteristics of the R biotype were discovered in a comparative test of the effects of 24 different antimitotic compounds on the R biotype and susceptible (S) wild-type Eleusine. The compounds tested could be classified into three groups based upon their effects on mitosis in root tips of the susceptible (S) biotype. Class I compounds induced effects like the well known mitotic disrupter colchicine: absence of cortical and spindle microtubules, mitosis arrested at prometaphase, and the formation of polymorphic nuclei after arrested mitosis. The R biotype was resistant to treatment with some class I inhibitors (all dinitroaniline herbicides and amiprophosmethyl) but not all (e.g. colchicine, podophyllotoxin, vinblastine, and pronamide). Roots of the R biotype, when treated with either dinitroaniline herbicides or amiprophosmethyl, exhibited no or only small increases in the mitotic index nor were the spindle and cortical microtubules affected. Compounds of class II (carbamate herbicides and griseofulvin) cause misorientation of microtubules which results in multinucleated cells. Compounds of class III (caffeine and structually related alkaloids) cause imcomplete cell walls to form at telophase. Each of these last two classes of compounds affected the R biotype more than the S biotype (supersensitivity). The cross-resistance and high levels of resistance of the R biotype of Eleusine to the dinitroaniline herbicides and the structurally distinct herbicide, amiprophosmethyl, indicate that a mechanism of resistance based upon metabolic modification, translocation, or compartmentation of the herbicides is probably not operative.

Cadmium-mediated resistance to metals and antibiotics in a cyanobacterium

Energy Technology Data Exchange (ETDEWEB)

Singh, S.P.; Pandey, A.K.

1982-01-01

Cadmium-resistant strains of the cyanobacterium Nostoc calcicola were isolated through the step-wise transfer of the organism to higher levels of the metal. One of the Cd-resistant strains (CDsup(r)-10) showed cross-resistance to antibiotics like neomycin (1 ..mu..g/ml), chloramphenicol (3 ..mu..g/ml) but not to streptomycin. The Cd-resistant strain also tolerated elevated levels of metals such as zinc 20 ppm) and mercury (1 ppm). The stability of the metal-resistance required the presence of Cd/sup 2 +/ ions in the growth medium. It is suggested that metal resistance may also be determined by gene(s) on the antibiotic resistance plasmids in cyanobacteria.

Guideline recommendations and antimicrobial resistance: the need for a change.

Science.gov (United States)

Elias, Christelle; Moja, Lorenzo; Mertz, Dominik; Loeb, Mark; Forte, Gilles; Magrini, Nicola

2017-07-26

Antimicrobial resistance has become a global burden for which inappropriate antimicrobial use is an important contributing factor. Any decisions on the selection of antibiotics use should consider their effects on antimicrobial resistance. The objective of this study was to assess the extent to which antibiotic prescribing guidelines have considered resistance patterns when making recommendations for five highly prevalent infectious syndromes. We used Medline searches complemented with extensive use of Web engine to identify guidelines on empirical treatment of community-acquired pneumonia, urinary tract infections, acute otitis media, rhinosinusitis and pharyngitis. We collected data on microbiology and resistance patterns and identified discrete pattern categories. We assessed the extent to which recommendations considered resistance, in addition to efficacy and safety, when recommending antibiotics. We identified 135 guidelines, which reported a total of 251 recommendations. Most (103/135, 79%) were from developed countries. Community-acquired pneumonia was the syndrome mostly represented (51, 39%). In only 16 (6.4%) recommendations, selection of empirical antibiotic was discussed in relation to resistance and specific microbiological data. In a further 69 (27.5%) recommendations, references were made in relation to resistance, but the attempt was inconsistent. Across syndromes, 12 patterns of resistance with implications on recommendations were observed. 50% to 75% of recommendations did not attempt to set recommendation in the context of these patterns. There is consistent evidence that guidelines on empirical antibiotic use did not routinely consider resistance in their recommendations. Decision-makers should analyse and report the extent of local resistance patterns to allow better decision-making. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless

Linezolid-resistant clinical isolates of enterococci and Staphylococcus cohnii from a multicentre study in China: molecular epidemiology and resistance mechanisms.

Science.gov (United States)

Chen, Hongbin; Wu, Weiyuan; Ni, Ming; Liu, Yingmei; Zhang, Jixia; Xia, Fei; He, Wenqiang; Wang, Qi; Wang, Zhanwei; Cao, Bin; Wang, Hui

2013-10-01

Genetic characterisation of linezolid-resistant Gram-positive cocci in a multicentre study in China has not been reported previously. To study the mechanism underlying the resistance of linezolid-resistant isolates, nine Enterococcus faecalis, one Enterococcus faecium and three Staphylococcus cohnii isolates with various levels of resistance were collected from five hospitals across China in 2009-2012. The nine E. faecalis isolates were classified into seven sequence types, indicating that these linezolid-resistant E. faecalis isolates were polyclonal. Enterococci isolates had reduced susceptibility to linezolid (MICs of 4-8 mg/L) and had mutation of ribosomal protein L3, with three also having mutation of L4, but without the multidrug resistance gene cfr or the 23S rRNA mutation G2576T. The three S. cohnii isolates were highly resistant to linezolid (MICs of 64 mg/L to >256 mg/L), harboured the cfr gene and had the 23S rRNA mutation G2576T. Southern blotting indicated that the cfr gene of these three isolates resided on different plasmids (pHK01, pRM01 and pRA01). In plasmid pHK01, IS21-558 and the cfr gene were integrated into transposon Tn558. In plasmids pRM01 and pRA01, the cfr gene was flanked by two copies of an IS256-like insertion sequence, indicating that the transferable form of linezolid resistance is conferred by the cfr gene. In conclusion, the emergence of linezolid-resistant Gram-positive cocci in different regions of China is of concern. The cfr gene and the 23S rRNA mutation contribute to high-level linezolid resistance in S. cohnii, and the L3 and L4 mutations are associated with low-level linezolid resistance in enterococci. Copyright © 2013 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

An Experimental Study of the Electrical Contact Resistance in Resistance Welding

DEFF Research Database (Denmark)

Song, Quanfeng; Zhang, Wenqi; Bay, Niels

2005-01-01

Electrical contact resistance is of critical importance in resistance welding. In this article, the contact resistance is experimentally investigated for welding mild steel, stainless steel, and aluminum to themselves. A parametric study was carried out on a Gleeble® machine, investigating...

Beyond Student Resistance: A Pedagogy of Possibility.

Science.gov (United States)

Lindquist, Barbara

1994-01-01

Critiques the concept of resistance in interpreting students' behaviors and attitudes, examining political, social, and psychological connotations of resistance and contradictory ways that educators employ the concept. The paper explains limitations imposed on education by the concept, noting the work of educators who reassess the implications of…

Resistant plasmid profile analysis of multidrug resistant Escherichia ...

African Journals Online (AJOL)

Multiple drug resistance isolates causing UTI has seri- ous implications for the empiric therapy against patho- genic isolates and for the possible co-selection of antimicrobial resistant mediated by multi drug resistant plasmids21,22. E. coli from clinical isolates are known to harbour plasmids of different molecular sizes23.

Multidrug-resistant tuberculosis

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McNerney Ruth

2008-01-01

Full Text Available Abstract Background With almost 9 million new cases each year, tuberculosis remains one of the most feared diseases on the planet. Led by the STOP-TB Partnership and WHO, recent efforts to combat the disease have made considerable progress in a number of countries. However, the emergence of mutated strains of Mycobacterium tuberculosis that are resistant to the major anti-tuberculosis drugs poses a deadly threat to control efforts. Multidrug-resistant tuberculosis (MDR-TB has been reported in all regions of the world. More recently, extensively drug resistant-tuberculosis (XDR-TB that is also resistant to second line drugs has emerged in a number of countries. To ensure that adequate resources are allocated to prevent the emergence and spread of drug resistance it is important to understand the scale of the problem. In this article we propose that current methods of describing the epidemiology of drug resistant tuberculosis are not adequate for this purpose and argue for the inclusion of population based statistics in global surveillance data. Discussion Whereas the prevalence of tuberculosis is presented as the proportion of individuals within a defined population having disease, the prevalence of drug resistant tuberculosis is usually presented as the proportion of tuberculosis cases exhibiting resistance to anti-tuberculosis drugs. Global surveillance activities have identified countries in Eastern Europe, the former Soviet Union and regions of China as having a high proportion of MDR-TB cases and international commentary has focused primarily on the urgent need to improve control in these settings. Other regions, such as sub-Saharan Africa have been observed as having a low proportion of drug resistant cases. However, if one considers the incidence of new tuberculosis cases with drug resistant disease in terms of the population then countries of sub-Saharan Africa have amongst the highest rates of transmitted MDR-TB in the world. We propose

Genomic organization of a vancomycin-resistant staphylococcus aureus

International Nuclear Information System (INIS)

Mirani, A.Z.; Jamil, N.

2013-01-01

Objective: To study the genomic organization of vancomycin resistance in a local isolate of vancomycin resistant Staphylococcus aureus (VRSA). Study Design: Experimental study. Place and Duration of Study: Department of Microbiology, University of Karachi, January 2008 through December 2010. Methodology: A vancomycin-resistant Staphylococcus aureus (VRSA-CP2) isolate (MIC 16 mu g/ml) was isolated from a local hospital of Karachi. Species identification was confirmed by Gram staining, standard biochemical tests and PCR amplification of the nuc gene. The vancomycin MIC was re-confirmed by E-test. For the genetic determination of vancomycin resistance, in-vitro amplification of vanA cassette was performed by using plasmid DNA of CP2, CP2's transformant as template on MWG Thermo-Cycler. Amplified products of vanR, vanS, vanH, vanA, vanY, orf2, orf1D, orf2E, orf-Rev and IS element genes were subjected to Sanger's electrophoresis based sequence determination using specific primers. The Basic Local Alignment Search Tool (BLAST) algorithm was used to identify sequences in GenBank with similarities to the vanA cassette genes. Results: The vancomycin-resistant isolate CP2 was found to be resistant to oxacillin, chloramphenicol, erythromycin, rifampicin, gentamicin, tetracycline and ciprofloxacin, as well. The isolate CP2 revealed four bands: one of large molecular size approx 56.4 kb and three of small size approx 6.5 kb, approx 6.1 kb and approx 1.5 kb by agarose gel electrophoresis indicating the presence of 3 plasmids. The plasmid DNA of isolate CP2 was analyzed by PCR for the presence of the van cassettes with each of the vanA , vanB and vanC specific primers. It carried vanA cassette, which comprises of vanR, vanS, vanH, vanA, vanY, and orf2. The vanA cassette of isolate CP2 also carried an insertion element (IS). However, it did not show the PCR product for orf1. Vancomycin resistance was successfully transferred from the donor CP2 to a vancomycin-sensitive recipient S

Treatment resistant adolescent depression with upper airway resistance syndrome treated with rapid palatal expansion: a case report

Directory of Open Access Journals (Sweden)

Miller Paul

2012-12-01

Full Text Available Abstract Introduction To the best of our knowledge, this is the first report of a case of treatment-resistant depression in which the patient was evaluated for sleep disordered breathing as the cause and in which rapid palatal expansion to permanently treat the sleep disordered breathing produced a prolonged symptom-free period off medication. Case presentation An 18-year-old Caucasian man presented to our sleep disorders center with chronic severe depression that was no longer responsive to medication but that had recently responded to electroconvulsive therapy. Ancillary, persistent symptoms included mild insomnia, moderate to severe fatigue, mild sleepiness and severe anxiety treated with medication. Our patient had no history of snoring or witnessed apnea, but polysomnography was consistent with upper airway resistance syndrome. Although our patient did not have an orthodontic indication for rapid palatal expansion, rapid palatal expansion was performed as a treatment of his upper airway resistance syndrome. Following rapid palatal expansion, our patient experienced a marked improvement of his sleep quality, anxiety, fatigue and sleepiness. His improvement has been maintained off all psychotropic medication and his depression has remained in remission for approximately two years following his electroconvulsive therapy. Conclusions This case report introduces the possibility that unrecognized sleep disordered breathing may play a role in adolescent treatment-resistant depression. The symptoms of upper airway resistance syndrome are non-specific enough that every adolescent with depression, even those responding to medication, may have underlying sleep disordered breathing. In such patients, rapid palatal expansion, by widening the upper airway and improving airflow during sleep, may produce a prolonged improvement of symptoms and a tapering of medication. Psychiatrists treating adolescents may benefit from having another treatment option for

Shear flow generation and turbulence suppression by resistive ballooning and resistive interchange modes

International Nuclear Information System (INIS)

Guzdar, P.N.; Drake, J.F.

1993-01-01

The generation of shear flow by resistive ballooning modes and resistive interchange modes is compared and contrasted using a 3-D fluid code. The resistive ballooning modes give rise to poloidally asymmetric transport and hence drive poloidal rotation due to the Reynold's Stress as well as the anomalous Stringer/Winsor mechanism. On the other hand the resistive interchange mode can drive shear flow only through the Reynold's Stress. The studies show that if the self-consistent sheared flow is suppressed, the resistive ballooning modes give rise to a larger anomalous transport than produced by the resistive interchange modes. Furthermore the shear flow generated by the resistive ballooning modes is larger than that driven by the resistive interchange modes due to the combined effect of the dual mechanisms stated earlier. As a consequence strong suppression of the fluctuations as well as reduction of the transport occurs for resistive ballooning modes. On the other hand, for the resistive interchange modes the level of fluctuation as well as the anomalous transport is not reduced by the self consistent shear flow generated by the Reynold's Stress. This latter result is in agreement with some earlier 3-D simulation of resistive interchange modes

Surveillance for vancomycin resistant enterococci in a tertiary ...

African Journals Online (AJOL)

Three were resistant to Ampicillin and nine to Ciprofloxacin but all were susceptible to Linezolid. High-level resistance to Gentamicin was found in four VRE isolates. Conclusion: There is a low prevalence of VRE in Lagos University Teaching Hospital which may be spreading among patients in affected wards. Keywords: ...

ZK DrugResist 2.0: A TextMiner to extract semantic relations of drug resistance from PubMed.

Science.gov (United States)

Khalid, Zoya; Sezerman, Osman Ugur

2017-05-01

Extracting useful knowledge from an unstructured textual data is a challenging task for biologists, since biomedical literature is growing exponentially on a daily basis. Building an automated method for such tasks is gaining much attention of researchers. ZK DrugResist is an online tool that automatically extracts mutations and expression changes associated with drug resistance from PubMed. In this study we have extended our tool to include semantic relations extracted from biomedical text covering drug resistance and established a server including both of these features. Our system was tested for three relations, Resistance (R), Intermediate (I) and Susceptible (S) by applying hybrid feature set. From the last few decades the focus has changed to hybrid approaches as it provides better results. In our case this approach combines rule-based methods with machine learning techniques. The results showed 97.67% accuracy with 96% precision, recall and F-measure. The results have outperformed the previously existing relation extraction systems thus can facilitate computational analysis of drug resistance against complex diseases and further can be implemented on other areas of biomedicine. Copyright © 2017 Elsevier Inc. All rights reserved.

Receiver Expectations: Toward a New Model of Resistance to Persuasion.

Science.gov (United States)

Miller, Michael D.; Burgoon, Michael

Communication research long has noted how pretreatment strategies ("inoculations") induce resistance to persuasion, but a new model proposes that resistance is an integral part of the persuasion process. Using the inoculation framework, researchers showed the importance of threats to an individual's attitudes in developing resistance to…

A passive quantitative measurement of airway resistance using depth data.

Science.gov (United States)

Ostadabbas, Sarah; Bulach, Christoph; Ku, David N; Anderson, Larry J; Ghovanloo, Maysam

2014-01-01

The Respiratory Syncytial Virus (RSV) is the most common cause of serious lower respiratory tract infections in infants and young children. RSV often causes increased airway resistance, clinically detected as wheezing by chest auscultation. In this disease, expiratory flows are significantly reduced due to the high resistance in patient's airway passages. A quantitative method for measuring resistance can have a great benefit to diagnosis and management of children with RSV infections as well as with other lung diseases. Airway resistance is defined as the lung pressure divided by the airflow. In this paper, we propose a method to quantify resistance through a simple, non-contact measurement of chest volume that can act as a surrogate measure of the lung pressure and volumetric airflow. We used depth data collected by a Microsoft Kinect camera for the measurement of the lung volume over time. In our experimentation, breathing through a number of plastic straws induced different airway resistances. For a standard spirometry test, our volume/flow estimation using Kinect showed strong correlation with the flow data collected by a commercially-available spirometer (five subjects, each performing 20 breathing trials, correlation coefficient = 0.88, with 95% confidence interval). As the number of straws decreased, emulating a higher airway obstruction, our algorithm was sufficient to distinguish between several levels of airway resistance.

Insecticide resistance and resistance mechanisms in bed bugs, Cimex spp. (Hemiptera: Cimicidae).

Science.gov (United States)

Dang, Kai; Doggett, Stephen L; Veera Singham, G; Lee, Chow-Yang

2017-06-29

The worldwide resurgence of bed bugs [both Cimex lectularius L. and Cimex hemipterus (F.)] over the past two decades is believed in large part to be due to the development of insecticide resistance. The transcriptomic and genomic studies since 2010, as well as morphological, biochemical and behavioral studies, have helped insecticide resistance research on bed bugs. Multiple resistance mechanisms, including penetration resistance through thickening or remodelling of the cuticle, metabolic resistance by increased activities of detoxification enzymes (e.g. cytochrome P450 monooxygenases and esterases), and knockdown resistance by kdr mutations, have been experimentally identified as conferring insecticide resistance in bed bugs. Other candidate resistance mechanisms, including behavioral resistance, some types of physiological resistance (e.g. increasing activities of esterases by point mutations, glutathione S-transferase, target site insensitivity including altered AChEs, GABA receptor insensitivity and altered nAChRs), symbiont-mediated resistance and other potential, yet undiscovered mechanisms may exist. This article reviews recent studies of resistance mechanisms and the genes governing insecticide resistance, potential candidate resistance mechanisms, and methods of monitoring insecticide resistance in bed bugs. This article provides an insight into the knowledge essential for the development of both insecticide resistance management (IRM) and integrated pest management (IPM) strategies for successful bed bug management.

Cross-resistance and Inheritance of Resistance to Emamectin Benzoate in Spodoptera exigua (Lepidoptera: Noctuidae).

Science.gov (United States)

Che, Wunan; Huang, Jianlei; Guan, Fang; Wu, Yidong; Yang, Yihua

2015-08-01

Beet armyworm, Spodoptera exigua (Hübner), is a worldwide pest of many crops. Chemical insecticides are heavily used for its control in China, and serious resistance has been evolved in the field to a variety of insecticides including emamectin benzoate. Through repeated backcrossing to a susceptible strain (WH-S) and selection with emamectin benzoate, the trait conferring resistance to emamectin benzoate in a field-collected population of S. exigua (moderately resistant to emamectin benzoate and strongly resistant to pyrethroids and indoxacarb) was introgressed into WH-S to generate a near-isogenic resistant strain (WH-EB). Compared with WH-S, the WH-EB strain developed a 1,110-fold resistance to emamectin benzoate and a high level of cross-resistance to abamectin (202-fold), with low levels of cross-resistance to cypermethrin (10-fold) and chlorfluazuron (7-fold), but no cross-resistance to representatives of another six different classes of insecticides (chlorantraniliprole, chlorfenapyr, indoxacarb, spinosad, tebufenozide, and chlorpyrifos). Resistance to emamectin benzoate in WH-EB was autosomal, incompletely dominant, and polygenic. Limited cross-resistance in WH-EB indicates that emamectin benzoate can be rotated with other classes of insecticides to which it does not show cross-resistance to delay the evolution of resistance in S. exigua. The incompletely dominant nature of resistance in S. exigua may explain the rapid evolution of resistance to emamectin benzoate in the field, and careful deployment of this chemical within a resistance management program should be considered. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Electrically resistive coating for remediation (regeneration) of a diesel particulate filter and method

Science.gov (United States)

Phelps, Amanda C [Malibu, CA; Kirby, Kevin K [Calabasas Hills, CA; Gregoire, Daniel J [Thousand Oaks, CA

2012-02-14

A resistively heated diesel particulate filter (DPF). The resistively heated DPF includes a DPF having an inlet surface and at least one resistive coating on the inlet surface. The at least one resistive coating is configured to substantially maintain its resistance in an operating range of the DPF. The at least one resistive coating has a first terminal and a second terminal for applying electrical power to resistively heat up the at least one resistive coating in order to increase the temperature of the DPF to a regeneration temperature. The at least one resistive coating includes metal and semiconductor constituents.

Drug Resistance Patterns of Escherichia coli in Ethiopia: A Meta-Analysis.

Science.gov (United States)

Tuem, Kald Beshir; Gebre, Abadi Kahsu; Atey, Tesfay Mehari; Bitew, Helen; Yimer, Ebrahim M; Berhe, Derbew Fikadu

2018-01-01

Antimicrobial drug resistance is a global threat for treatment of infectious diseases and costs life and money and threatens health delivery system's effectiveness. The resistance of E. coli to frequently utilized antimicrobial drugs is becoming a major challenge in Ethiopia. However, there is no inclusive countrywide study. Therefore, this study intended to assess the prevalence of E. coli resistance and antimicrobial-specific resistance pattern among E. coli clinical isolates in Ethiopia. Articles were retrieved from PubMed, Embase, and grey literature from 2007 to 2017. The main outcome measures were overall E. coli and drug-specific resistance patterns. A random-effects model was used to determine pooled prevalence with 95% confidence interval (CI), using DerSimonian and Laird method. In addition, subgroup analysis was conducted to improve the outcome. The study bias was assessed by Begg's funnel plot. This study was registered in PROSPERO as follows: PROSPERO 2017: CRD42017070106. Of 164 articles retrieved, 35 articles were included. A total of 19,235 study samples participated in the studies and 2,635 E. coli strains were isolated. Overall, E. coli antibacterial resistance was 45.38% (95% confidence interval (CI): 33.50 to 57.27). The resistance pattern ranges from 62.55% in Addis Ababa to 27.51% in Tigray region. The highest resistance of E. coli reported was to ampicillin (83.81%) and amoxicillin (75.79%), whereas only 13.55% of E. coli isolates showed resistance to nitrofurantoin. E. coli antimicrobial resistance remains high with disparities observed among regions. The bacterium was found to be highly resistant to aminopenicillins. The finding implies the need for effective prevention strategies for the E. coli drug resistance and calls for multifaceted approaches with full involvement of all stakeholders.

Factors affecting host range in a generalist seed pathogen of semi-arid shrublands

Science.gov (United States)

Julie Beckstead; Susan E. Meyer; Kurt O. Reinhart; Kellene M. Bergen; Sandra R. Holden; Heather F. Boekweg

2014-01-01

Generalist pathogens can exhibit differential success on different hosts, resulting in complex host range patterns. Several factors operate to reduce realized host range relative to potential host range, particularly under field conditions. We explored factors influencing host range of the naturally occurring generalist ascomycete grass seed pathogen Pyrenophora...

Pyrethroid resistance and cross-resistance in the German cockroach, Blattella germanica (L).

Science.gov (United States)

Wei, Y; Appel, A G; Moar, W J; Liu, N

2001-11-01

A German cockroach (Blatella germanica (L)) strain, Apyr-R, was collected from Opelika, Alabama after control failures with pyrethroid insecticides. Levels of resistance to permethrin and deltamethrin in Apyr-R (97- and 480-fold, respectively, compared with a susceptible strain, ACY) were partially or mostly suppressed by piperonyl butoxide (PBO) and S,S,S,-tributylphosphorotrithioate (DEF), suggesting that P450 monooxygenases and hydrolases are involved in resistance to these two pyrethroids in Apyr-R. However, incomplete suppression of pyrethroid resistance with PBO and DEF implies that one or more additional mechanisms are involved in resistance. Injection, compared with topical application, resulted in 43- and 48-fold increases in toxicity of permethrin in ACY and Apyr-R, respectively. Similarly, injection increased the toxicity of deltamethrin 27-fold in ACY and 28-fold in Apyr-R. These data indicate that cuticular penetration is one of the obstacles for the effectiveness of pyrethroids against German cockroaches. However, injection did not change the levels of resistance to either permethrin or deltamethrin, suggesting that a decrease in the rate of cuticular penetration may not play an important role in pyrethroid resistance in Apyr-R. Apyr-R showed cross-resistance to imidacloprid, with a resistance ratio of 10. PBO treatment resulted in no significant change in the toxicity of imidacloprid, implying that P450 monooxygenase-mediated detoxication is not the mechanism responsible for cross-resistance. Apyr-R showed no cross-resistance to spinosad, although spinosad had relatively low toxicity to German cockroaches compared with other insecticides tested in this study. This result further confirmed that the mode of action of spinosad to insects is unique. Fipronil, a relatively new insecticide, was highly toxic to German cockroaches, and the multi-resistance mechanisms in Apyr-R did not confer significant cross-resistance to this compound. Thus, we propose

Numerical analysis of a polysilicon-based resistive memory device

KAUST Repository

Berco, Dan; Chand, Umesh

2018-01-01

This study investigates a conductive bridge resistive memory device based on a Cu top electrode, 10-nm polysilicon resistive switching layer and a TiN bottom electrode, by numerical analysis for $$10^{3}$$103 programming and erase simulation cycles

Cross-Resistance of UV- or Chlorine Dioxide-Resistant Echovirus 11 to Other Disinfectants

Directory of Open Access Journals (Sweden)

Qingxia Zhong

2017-10-01

Full Text Available The emergence of waterborne viruses with resistance to disinfection has been demonstrated in the laboratory and in the environment. Yet, the implications of such resistance for virus control remain obscure. In this study we investigate if viruses with resistance to a given disinfection method exhibit cross-resistance to other disinfectants. Chlorine dioxide (ClO2- or UV-resistant populations of echovirus 11 were exposed to five inactivating treatments (free chlorine, ClO2, UV radiation, sunlight, and heat, and the extent of cross-resistance was determined. The ClO2-resistant population exhibited cross-resistance to free chlorine, but to none of the other inactivating treatments tested. We furthermore demonstrated that ClO2 and free chlorine act by a similar mechanism, in that they mainly inhibit the binding of echovirus 11 to its host cell. As such, viruses with host binding mechanisms that can withstand ClO2 treatment were also better able to withstand oxidation by free chlorine. Conversely, the UV-resistant population was not significantly cross-resistant to any other disinfection treatment. Overall, our results indicate that viruses with resistance to multiple disinfectants exist, but that they can be controlled by inactivating methods that operate by a distinctly different mechanism. We therefore suggest to utilize two disinfection barriers that act by different mechanisms in order to control disinfection-resistant viruses.

Cellobiose dehydrogenase of Chaetomium sp. INBI 2-26(-): structural basis of enhanced activity toward glucose at neutral pH.

Science.gov (United States)

Vasilchenko, Liliya G; Karapetyan, Karen N; Yershevich, Olga P; Ludwig, Roland; Zamocky, Marcel; Peterbauer, Clemens K; Haltrich, Dietmar; Rabinovich, Mikhail L

2011-05-01

Cellobiose dehydrogenase (CDH) is an extracellular fungal flavocytochrome specifically oxidizing cellooligosaccharides and lactose to corresponding (-lactones by a variety of electron acceptors. In contrast to basidiomycetous CDHs, CDHs of ascomycetes also display certain activity toward glucose. The objective of this study was to establish the structural reasons of such an activity of CDH from mesophilic ascomycete Chaetomium sp. INBI 2-26 (ChCDH). The complete amino acid sequence of ChCDH displayed high levels of similarity with the amino acid sequences of CDHs from the thermophilic fungi Thielavia heterotallica and Myriococcum thermophilum. Peptide mass fingerprinting of purified ChCDH provided evidence for the oxidation of methionine residues in the FAD-domain. Comparative homology modeling of the structure of the ChCDH FAD-domain in complex with the transition state analog based on the structure of the same complex of basidiomycetous CDH (1NAA) as template indicated possible structural reasons for the enhanced activity of ascomycetous CDHs toward glucose at neutral pH, which is a prerequisite for application of CDH in a variety of biocompatible biosensors and biofuel cells. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

plasmid mediated resistance in multidrug resistant bacteria isolated

African Journals Online (AJOL)

User

PLASMID MEDIATED RESISTANCE IN MULTIDRUG RESISTANT BACTERIA. ISOLATED FROM CHILDREN WITH SUSPECTED SEPTICAEMIA IN ZARIA,. NIGERIA. AbdulAziz, Z. A.,1* Ehinmidu, J. O.,1 Adeshina, G. O.,1 Pala, Y. Y2., Yusuf, S. S2. and. Bugaje, M. A.3. 1Department of Pharmaceutics and Pharmaceutical ...

Plasma resistivity in a slow rising current theta-pinch device

International Nuclear Information System (INIS)

Kayama, Milton Eiji; Dobrowolsky, Marcelo Shubert; Honda, Roberto Yzumi; Aramaki, Emilia Akemi; Algatti, Mauricio Antonio

1998-01-01

Anomalous behavior of plasma resistivity was observed in a Theta-pinch plasma. A comparative analysis was performed with a hybrid numerical code where the Chodura s resistivity algorithm is included. Good agreement was found in the radial plasma dynamic description. The experimental value of resistivity at null field point was found to be one order of magnitude greater than the theoretical prediction. (author)

A horizontally gene transferred copper resistance locus confers hyper‐resistance to antibacterial copper toxicity and enables survival of community acquired methicillin resistant Staphylococcus aureus USA300 in macrophages

Science.gov (United States)

Purves, Joanne; Thomas, Jamie; Riboldi, Gustavo P.; Zapotoczna, Marta; Tarrant, Emma; Andrew, Peter W.; Londoño, Alejandra; Planet, Paul J.; Geoghegan, Joan A.; Waldron, Kevin J.

2018-01-01

Summary Excess copper is highly toxic and forms part of the host innate immune system's antibacterial arsenal, accumulating at sites of infection and acting within macrophages to kill engulfed pathogens. We show for the first time that a novel, horizontally gene transferred copper resistance locus (copXL), uniquely associated with the SCCmec elements of the highly virulent, epidemic, community acquired methicillin resistant Staphylococcus aureus (CA‐MRSA) USA300, confers copper hyper‐resistance. These genes are additional to existing core genome copper resistance mechanisms, and are not found in typical S. aureus lineages, but are increasingly identified in emerging pathogenic isolates. Our data show that CopX, a putative P1B‐3‐ATPase efflux transporter, and CopL, a novel lipoprotein, confer copper hyper‐resistance compared to typical S. aureus strains. The copXL genes form an operon that is tightly repressed in low copper environments by the copper regulator CsoR. Significantly, CopX and CopL are important for S. aureus USA300 intracellular survival within macrophages. Therefore, the emergence of new S. aureus clones with the copXL locus has significant implications for public health because these genes confer increased resistance to antibacterial copper toxicity, enhancing bacterial fitness by altering S. aureus interaction with innate immunity. PMID:29521441

Extensively Drug-Resistant Tuberculosis: Principles of Resistance, Diagnosis, and Management.

Science.gov (United States)

Wilson, John W; Tsukayama, Dean T

2016-04-01

Extensively drug-resistant (XDR) tuberculosis (TB) is an unfortunate by-product of mankind's medical and pharmaceutical ingenuity during the past 60 years. Although new drug developments have enabled TB to be more readily curable, inappropriate TB management has led to the emergence of drug-resistant disease. Extensively drug-resistant TB describes Mycobacterium tuberculosis that is collectively resistant to isoniazid, rifampin, a fluoroquinolone, and an injectable agent. It proliferates when established case management and infection control procedures are not followed. Optimized treatment outcomes necessitate time-sensitive diagnoses, along with expanded combinations and prolonged durations of antimicrobial drug therapy. The challenges to public health institutions are immense and most noteworthy in underresourced communities and in patients coinfected with human immunodeficiency virus. A comprehensive and multidisciplinary case management approach is required to optimize outcomes. We review the principles of TB drug resistance and the risk factors, diagnosis, and managerial approaches for extensively drug-resistant TB. Treatment outcomes, cost, and unresolved medical issues are also discussed. Copyright © 2016 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.

Effect of Polysaccharide from Cordyceps militaris (Ascomycetes) on Physical Fatigue Induced by Forced Swimming.

Science.gov (United States)

Xu, Yan-Feng

2016-01-01

Cordyceps militaris is the one of the most important medicinal mushrooms, widely used in East Asian countries. Polysaccharide is considered to be the principal active component in C. militaris and has a wide range of biological and pharmacological properties. This study was undertaken to investigate the effect of polysaccharide from C. militaris (PCM) on physical fatigue induced in animals through a forced swimming test. The mice were divided into 4 groups receiving 28 days' treatment with drinking water (exercise control) or low-, medium-, and high-dose PCM (40, 80, and 160 mg/kg/day, respectively). After 28 days, the mice were subjected to the forced swimming test; the exhaustive swimming time was measured and fatigue-related biochemical parameters, including serum lactic acid, urea nitrogen, creatine kinase, alanine aminotransferase, aspartate aminotransferase, superoxide dismutase, glutathi- one peroxidase, catalase, malondialdehyde, liver glycogen, and muscle glycogen, were analyzed. The results showed that PCM could significantly prolong the exhaustive swimming time of mice; decrease concentrations of serum lactic acid, urea nitrogen, creatine kinase, aspartate aminotransferase, alanine aminotransferase, and malondialdehyde; and increase liver and muscle glycogen contents and the concentrations of serum superoxide dismutase, glutathione per- oxidase, and catalase. The data suggest that PCM has an antifatigue effect, and it might become a new functional food or medicine for fatigue resistance.

Response of methicillin-resistant Staphylococcus aureus to amicoumacin A.

Directory of Open Access Journals (Sweden)

Amrita Lama

Full Text Available Amicoumacin A exhibits strong antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA, hence we sought to uncover its mechanism of action. Genome-wide transcriptome analysis of S. aureus COL in response to amicoumacin A showed alteration in transcription of genes specifying several cellular processes including cell envelope turnover, cross-membrane transport, virulence, metabolism, and general stress response. The most highly induced gene was lrgA, encoding an antiholin-like product, which is induced in cells undergoing a collapse of Δψ. Consistent with the notion that LrgA modulates murein hydrolase activity, COL grown in the presence of amicoumacin A showed reduced autolysis, which was primarily caused by lower hydrolase activity. To gain further insight into the mechanism of action of amicoumacin A, a whole genome comparison of wild-type COL and amicoumacin A-resistant mutants isolated by a serial passage method was carried out. Single point mutations generating codon substitutions were uncovered in ksgA (encoding RNA dimethyltransferase, fusA (elongation factor G, dnaG (primase, lacD (tagatose 1,6-bisphosphate aldolase, and SACOL0611 (a putative glycosyl transferase. The codon substitutions in EF-G that cause amicoumacin A resistance and fusidic acid resistance reside in separate domains and do not bring about cross resistance. Taken together, these results suggest that amicoumacin A might cause perturbation of the cell membrane and lead to energy dissipation. Decreased rates of cellular metabolism including protein synthesis and DNA replication in resistant strains might allow cells to compensate for membrane dysfunction and thus increase cell survivability.

A self-consistent nonlinear theory of resistive-wall instability in a relativistic electron beam

International Nuclear Information System (INIS)

Uhm, H.S.

1994-01-01

A self-consistent nonlinear theory of resistive-wall instability is developed for a relativistic electron beam propagating through a grounded cylindrical resistive tube. The theory is based on the assumption that the frequency of the resistive-wall instability is lower than the cutoff frequency of the waveguide. The theory is concentrated on study of the beam current modulation directly related to the resistive-wall klystron, in which a relativistic electron beam is modulated at the first cavity and propagates downstream through the resistive wall. Because of the self-excitation of the space charge waves by the resistive-wall instability, a highly nonlinear current modulation of the electron beam is accomplished as the beam propagates downstream. A partial integrodifferential equation is obtained in terms of the initial energy modulation (ε), the self-field effects (h), and the resistive-wall effects (κ). Analytically investigating the partial integrodifferential equation, a scaling law of the propagation distance z m at which the maximum current modulation occurs is obtained. It is found in general that the self-field effects dominate over the resistive-wall effects at the beginning of the propagation. As the beam propagates farther downstream, the resistive-wall effects dominate. Because of a relatively large growth rate of the instability, the required tube length of the klystron is short for most applications

Sponge Microbiota are a Reservoir of Functional Antibiotic Resistance Genes

DEFF Research Database (Denmark)

Versluis, Dennis; de Evgrafov, Mari Cristina Rodriguez; Sommer, Morten Otto Alexander

2016-01-01

examined sponges as a reservoir of antibiotic resistance. Sponges could be important in this respect because they often contain diverse microbial communities that have the capacity to produce bioactive metabolites. Here, we applied functional metagenomics to study the presence and diversity of functional...... resistance genes in the sponges Aplysina aerophoba, Petrosia ficiformis, and Corticium candelabrum. We obtained 37 insert sequences facilitating resistance to D-cycloserine (n = 6), gentamicin (n = 1), amikacin (n = 7), trimethoprim (n = 17), chloramphenicol (n = 1), rifampicin (n = 2) and ampicillin (n = 3......-resistance-conferring β-lactamase was identified in the genus Pseudovibrio with 41% global amino acid identity to the closest β-lactamase with demonstrated functionality, and subsequently classified into a new family termed PSV. Taken together, our results show that sponge microbiota host diverse and novel resistance...

The culturable soil antibiotic resistome: a community of multi-drug resistant bacteria.

Science.gov (United States)

Walsh, Fiona; Duffy, Brion

2013-01-01

Understanding the soil bacterial resistome is essential to understanding the evolution and development of antibiotic resistance, and its spread between species and biomes. We have identified and characterized multi-drug resistance (MDR) mechanisms in the culturable soil antibiotic resistome and linked the resistance profiles to bacterial species. We isolated 412 antibiotic resistant bacteria from agricultural, urban and pristine soils. All isolates were multi-drug resistant, of which greater than 80% were resistant to 16-23 antibiotics, comprising almost all classes of antibiotic. The mobile resistance genes investigated, (ESBL, bla NDM-1, and plasmid mediated quinolone resistance (PMQR) resistance genes) were not responsible for the respective resistance phenotypes nor were they present in the extracted soil DNA. Efflux was demonstrated to play an important role in MDR and many resistance phenotypes. Clinically relevant Burkholderia species are intrinsically resistant to ciprofloxacin but the soil Burkholderia species were not intrinsically resistant to ciprofloxacin. Using a phenotypic enzyme assay we identified the antibiotic specific inactivation of trimethoprim in 21 bacteria from different soils. The results of this study identified the importance of the efflux mechanism in the soil resistome and variations between the intrinsic resistance profiles of clinical and soil bacteria of the same family.

The culturable soil antibiotic resistome: a community of multi-drug resistant bacteria.

Directory of Open Access Journals (Sweden)

Fiona Walsh

Full Text Available Understanding the soil bacterial resistome is essential to understanding the evolution and development of antibiotic resistance, and its spread between species and biomes. We have identified and characterized multi-drug resistance (MDR mechanisms in the culturable soil antibiotic resistome and linked the resistance profiles to bacterial species. We isolated 412 antibiotic resistant bacteria from agricultural, urban and pristine soils. All isolates were multi-drug resistant, of which greater than 80% were resistant to 16-23 antibiotics, comprising almost all classes of antibiotic. The mobile resistance genes investigated, (ESBL, bla NDM-1, and plasmid mediated quinolone resistance (PMQR resistance genes were not responsible for the respective resistance phenotypes nor were they present in the extracted soil DNA. Efflux was demonstrated to play an important role in MDR and many resistance phenotypes. Clinically relevant Burkholderia species are intrinsically resistant to ciprofloxacin but the soil Burkholderia species were not intrinsically resistant to ciprofloxacin. Using a phenotypic enzyme assay we identified the antibiotic specific inactivation of trimethoprim in 21 bacteria from different soils. The results of this study identified the importance of the efflux mechanism in the soil resistome and variations between the intrinsic resistance profiles of clinical and soil bacteria of the same family.

Search Engine for Antimicrobial Resistance: A Cloud Compatible Pipeline and Web Interface for Rapidly Detecting Antimicrobial Resistance Genes Directly from Sequence Data.

Science.gov (United States)

Rowe, Will; Baker, Kate S; Verner-Jeffreys, David; Baker-Austin, Craig; Ryan, Jim J; Maskell, Duncan; Pearce, Gareth

2015-01-01

Antimicrobial resistance remains a growing and significant concern in human and veterinary medicine. Current laboratory methods for the detection and surveillance of antimicrobial resistant bacteria are limited in their effectiveness and scope. With the rapidly developing field of whole genome sequencing beginning to be utilised in clinical practice, the ability to interrogate sequencing data quickly and easily for the presence of antimicrobial resistance genes will become increasingly important and useful for informing clinical decisions. Additionally, use of such tools will provide insight into the dynamics of antimicrobial resistance genes in metagenomic samples such as those used in environmental monitoring. Here we present the Search Engine for Antimicrobial Resistance (SEAR), a pipeline and web interface for detection of horizontally acquired antimicrobial resistance genes in raw sequencing data. The pipeline provides gene information, abundance estimation and the reconstructed sequence of antimicrobial resistance genes; it also provides web links to additional information on each gene. The pipeline utilises clustering and read mapping to annotate full-length genes relative to a user-defined database. It also uses local alignment of annotated genes to a range of online databases to provide additional information. We demonstrate SEAR's application in the detection and abundance estimation of antimicrobial resistance genes in two novel environmental metagenomes, 32 human faecal microbiome datasets and 126 clinical isolates of Shigella sonnei. We have developed a pipeline that contributes to the improved capacity for antimicrobial resistance detection afforded by next generation sequencing technologies, allowing for rapid detection of antimicrobial resistance genes directly from sequencing data. SEAR uses raw sequencing data via an intuitive interface so can be run rapidly without requiring advanced bioinformatic skills or resources. Finally, we show that SEAR

Novel bacterial metabolite merochlorin A demonstrates in vitro activity against multi-drug resistant methicillin-resistant Staphylococcus aureus.

Directory of Open Access Journals (Sweden)

George Sakoulas

Full Text Available We evaluated the in vitro activity of a merochlorin A, a novel compound with a unique carbon skeleton, against a spectrum of clinically relevant bacterial pathogens and against previously characterized clinical and laboratory Staphylococcus aureus isolates with resistance to numerous antibiotics.Merochlorin A was isolated and purified from a marine-derived actinomycete strain CNH189. Susceptibility testing for merochlorin A was performed against previously characterized human pathogens using broth microdilution and agar dilution methods. Cytotoxicity was assayed in tissue culture assays at 24 and 72 hours against human HeLa and mouse sarcoma L929 cell lines.The structure of as new antibiotic, merochlorin A, was assigned by comprehensive spectroscopic analysis. Merochlorin A demonstrated in vitro activity against Gram-positive bacteria, including Clostridium dificile, but not against Gram negative bacteria. In S. aureus, susceptibility was not affected by ribosomal mutations conferring linezolid resistance, mutations in dlt or mprF conferring resistance to daptomycin, accessory gene regulator knockout mutations, or the development of the vancomycin-intermediate resistant phenotype. Merochlorin A demonstrated rapid bactericidal activity against MRSA. Activity was lost in the presence of 20% serum.The unique meroterpenoid, merochlorin A demonstrated excellent in vitro activity against S. aureus and C. dificile and did not show cross-resistance to contemporary antibiotics against Gram positive organisms. The activity was, however, markedly reduced in 20% human serum. Future directions for this compound may include evaluation for topical use, coating biomedical devices, or the pursuit of chemically modified derivatives of this compound that retain activity in the presence of serum.

Resistance and cross-resistance profile of the diaryltriazine NNRTI and candidate microbicide UAMC01398.

Science.gov (United States)

Ariën, Kevin K; Venkatraj, Muthusamy; Michiels, Johan; Joossens, Jurgen; Vereecken, Katleen; Van der Veken, Pieter; Heeres, Jan; De Winter, Hans; Heyndrickx, Leo; Augustyns, Koen; Vanham, Guido

2016-05-01

The resistance development, cross-resistance to other NNRTIs and the impact of resistance on viral replicative fitness were studied for the new and potent NNRTI UAMC01398. Resistance was selected by dose escalation and by single high-dose selection against a comprehensive panel of NNRTIs used as therapeutics and NNRTIs under investigation for pre-exposure prophylaxis of sexual HIV transmission. A panel of 27 site-directed mutants with single mutations or combinations of mutations involved in reverse transcriptase (RT) inhibitor-mediated resistance was developed and used to confirm resistance to UAMC01398. Cross-resistance to other NNRTIs was assessed, as well as susceptibility of UAMC01398-resistant HIV to diarylpyrimidine-resistant viruses. Finally, the impact of UAMC01398 resistance on HIV replicative fitness was studied. We showed that UAMC01398 has potent activity against dapivirine-resistant HIV, that at least four mutations in the RT are required in concert for resistance and that the resistance profile is similar to rilpivirine, both genotypically and phenotypically. Resistance development to UAMC01398 is associated with a severe fitness cost. These data, together with the enhanced safety profile and good solubility in aqueous gels, make UAMC01398 an excellent candidate for HIV topical prevention. © The Author 2016. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Resistance to Powdery Mildews

DEFF Research Database (Denmark)

Siwoszek, Agnieszka Izabela

in majority of them. Resistance to barley powdery mildew in the field is controlled by use of resistant varieties in a combination with fungicides. Early disease management is crucial for effective control. Yet, the pathogen commonly develops fungicide resistance due to simple point mutations. Several studies...... protection. In the present study, I provide an overview of the current knowledge about plant pathogens and plant disease resistance. I use Arabidopsis as a model to investigate the mechanism of non-host resistance, presumed to be the most durable and broad-spectrum form of resistance. I attempt to determine...

Autosomal male determination in a spinosad-resistant housefly strain from Denmark

DEFF Research Database (Denmark)

Højland, Dorte H; Scott, Jeffrey G; Vagn Jensen, Karl-Martin

2014-01-01

males in this strain. The factor responsible for spinosad resistance in the strain is unknown, but previous studies suggest a role of cytochrome P450s for detoxification of spinosad. Sex determination in the housefly is controlled by a male-determining factor (M), either located on the Y chromosome......BACKGROUND The housefly, Musca domestica L., is a global pest and has developed resistance to most insecticides applied for its control. The insecticide spinosad plays an important role in housefly control. Females of the Danish housefly strain 791spin are threefold more resistant to spinosad than...... of resistance to spinosad. Sex determination in 791spin is due to a male factor on autosome 3. CONCLUSIONS The most likely explanation for the differentiation of spinosad resistance between males and females is a recessive spinosad resistance factor on autosome III. © 2013 Society of Chemical Industry...

A novel Capsicum gene inhibits host-specific disease resistance to Phytophthora capsici.

Science.gov (United States)

Reeves, Gregory; Monroy-Barbosa, Ariadna; Bosland, Paul W

2013-05-01

A novel disease resistance inhibitor gene (inhibitor of P. capsici resistance [Ipcr]), found in the chile pepper (Capsicum annuum) variety 'New Mexico Capsicum Accession 10399' (NMCA10399), inhibits resistance to Phytophthora capsici but not to other species of Phytophthora. When a highly P. capsici-resistant variety was hybridized with NMCA10399, the resultant F1 populations, when screened, were completely susceptible to P. capsici for root rot and foliar blight disease syndromes, despite the dominance inheritance of P. capsici resistance in chile pepper. The F2 population displayed a 3:13 resistant-to-susceptible (R:S) ratio. The testcross population displayed a 1:1 R:S ratio, and a backcross population to NMCA10399 displayed complete susceptibility. These results demonstrate the presence of a single dominant inhibitor gene affecting P. capsici resistance in chile pepper. Moreover, when lines carrying the Ipcr gene were challenged against six Phytophthora spp., the nonhost resistance was not overcome. Therefore, the Ipcr gene is interfering with host-specific resistance but not the pathogen- or microbe-associated molecular pattern nonhost responses.

Within-host selection of drug resistance in a mouse model reveals dose-dependent selection of atovaquone resistance mutations

NARCIS (Netherlands)

Nuralitha, Suci; Murdiyarso, Lydia S.; Siregar, Josephine E.; Syafruddin, Din; Roelands, Jessica; Verhoef, Jan; Hoepelman, Andy I.M.; Marzuki, Sangkot

2017-01-01

The evolutionary selection of malaria parasites within an individual host plays a critical role in the emergence of drug resistance. We have compared the selection of atovaquone resistance mutants in mouse models reflecting two different causes of failure of malaria treatment, an inadequate

Atovaquone/proguanil resistance in Africa: a case report

DEFF Research Database (Denmark)

David, Kim P; Alifrangis, Michael; Salanti, Ali

2003-01-01

The Atovaquone/proguanil combination has quickly been established as an effective chemoprophylaxis for travellers to areas with chloroquineresistant Plasmodium falciparum malaria. We describe the molecular cause of the first reported case of primary Atovaquone/proguanil resistance observed in our...... department in a Plasmodium falciparum infected traveller returning from West Africa, and link our findings to other reports of resistance....

Antibiotic Resistant Bacteria And Their Associated Resistance Genes in a Conventional Municipal Wastewater Treatment Plant

KAUST Repository

Aljassim, Nada I.

2013-12-01

With water scarcity as a pressing issue in Saudi Arabia and other Middle Eastern countries, the treatment and reuse of municipal wastewater is increasingly being used as an alternative water source to supplement country water needs. Standards are in place to ensure a safe treated wastewater quality, however they do not regulate pathogenic bacteria and emerging contaminants. Information is lacking on the levels of risk to public health associated with these factors, the efficiency of conventional treatment strategies in removing them, and on wastewater treatment in Saudi Arabia in general. In this study, a municipal wastewater treatment plant in Saudi Arabia is investigated to assess the efficiency of conventional treatment in meeting regulations and removing pathogens and emerging contaminants. The study found pathogenic bacterial genera, antibiotic resistance genes and antibiotic resistant bacteria, many of which were multi-resistant in plant discharges. It was found that although the treatments are able to meet traditional quality guidelines, there remains a risk from the discussed contaminants with wastewater reuse. A deeper understanding of this risk, and suggestions for more thorough guidelines and monitoring are needed.

Resistant hypertension.

Science.gov (United States)

Wei, Fang-Fei; Zhang, Zhen-Yu; Huang, Qi-Fang; Yang, Wen-Yi; Staessen, Jan A

2018-06-15

The publication of the first non-randomised proof-of-concept trial of renal denervation as a treatment modality in treatment-resistant hypertension set the stage for a search for novel devices with the expectation that technology would reduce the burden of hypertension by reducing or eliminating the costly and lifelong use of blood pressure lowering medications. As we demonstrate in this review, this idea so attractive to manufacturers and invasive cardiologists and radiologists overlooked decades of careful pathophysiological research in a disease, which still remains enigmatic but remains the major cause of cardiovascular mortality worldwide. To make our point, we first reviewed the prevalence and risks associated with treatment-resistant hypertension. Next, we highlighted the key points required for the diagnosis of treatment-resistant hypertension, including the recording of the ambulatory blood pressure and the assessment of adherence to medication. Finally, we summarised new insights in the management of treatment-resistant hypertension by medication and devices and in the future research. Throughout our review, we focused on new evidence became available since 2013. Our conclusion is that optimising medical treatment based on simple algorithms remains the state of the art in treatment-resistant hypertension.

Measurement of microchannel fluidic resistance with a standard voltage meter

International Nuclear Information System (INIS)

Godwin, Leah A.; Deal, Kennon S.; Hoepfner, Lauren D.; Jackson, Louis A.; Easley, Christopher J.

2013-01-01

Highlights: ► Standard voltage meter used to measure fluidic resistance. ► Manual measurement takes a few seconds, akin to electrical resistance measurements. ► Measurement error is reduced compared to other approaches. ► Amenable to dynamic measurement of fluidic resistance. - Abstract: A simplified method for measuring the fluidic resistance (R fluidic ) of microfluidic channels is presented, in which the electrical resistance (R elec ) of a channel filled with a conductivity standard solution can be measured and directly correlated to R fluidic using a simple equation. Although a slight correction factor could be applied in this system to improve accuracy, results showed that a standard voltage meter could be used without calibration to determine R fluidic to within 12% error. Results accurate to within 2% were obtained when a geometric correction factor was applied using these particular channels. When compared to standard flow rate measurements, such as meniscus tracking in outlet tubing, this approach provided a more straightforward alternative and resulted in lower measurement error. The method was validated using 9 different fluidic resistance values (from ∼40 to 600 kPa s mm −3 ) and over 30 separately fabricated microfluidic devices. Furthermore, since the method is analogous to resistance measurements with a voltage meter in electrical circuits, dynamic R fluidic measurements were possible in more complex microfluidic designs. Microchannel R elec was shown to dynamically mimic pressure waveforms applied to a membrane in a variable microfluidic resistor. The variable resistor was then used to dynamically control aqueous-in-oil droplet sizes and spacing, providing a unique and convenient control system for droplet-generating devices. This conductivity-based method for fluidic resistance measurement is thus a useful tool for static or real-time characterization of microfluidic systems.

Prevalence of chlorhexidine-resistant methicillin-resistant Staphylococcus aureus following prolonged exposure.

Science.gov (United States)

Schlett, Carey D; Millar, Eugene V; Crawford, Katrina B; Cui, Tianyuan; Lanier, Jeffrey B; Tribble, David R; Ellis, Michael W

2014-08-01

Chlorhexidine has been increasingly utilized in outpatient settings to control methicillin-resistant Staphylococcus aureus (MRSA) outbreaks and as a component of programs for MRSA decolonization and prevention of skin and soft-tissue infections (SSTIs). The objective of this study was to determine the prevalence of chlorhexidine resistance in clinical and colonizing MRSA isolates obtained in the context of a community-based cluster-randomized controlled trial for SSTI prevention, during which 10,030 soldiers were issued chlorhexidine for body washing. We obtained epidemiological data on study participants and performed molecular analysis of MRSA isolates, including PCR assays for determinants of chlorhexidine resistance and high-level mupirocin resistance and pulsed-field gel electrophoresis (PFGE). During the study period, May 2010 to January 2012, we identified 720 MRSA isolates, of which 615 (85.4%) were available for molecular analysis, i.e., 341 clinical and 274 colonizing isolates. Overall, only 10 (1.6%) of 615 isolates were chlorhexidine resistant, including three from the chlorhexidine group and seven from nonchlorhexidine groups (P > 0.99). Five (1.5%) of the 341 clinical isolates and five (1.8%) of the 274 colonizing isolates harbored chlorhexidine resistance genes, and four (40%) of the 10 possessed genetic determinants for mupirocin resistance. All chlorhexidine-resistant isolates were USA300. The overall prevalence of chlorhexidine resistance in MRSA isolates obtained from our study participants was low. We found no association between extended chlorhexidine use and the prevalence of chlorhexidine-resistant MRSA isolates; however, continued surveillance is warranted, as this agent continues to be utilized for infection control and prevention efforts. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

A new production technique for wear resistant ring-hammers

Directory of Open Access Journals (Sweden)

Li Shifeng

2011-11-01

Full Text Available Based on a great number of laboratory experiments, a new technique has been developed for producing wear resistant ring-hammers. In this technology, lost foam casting with iron sand was combined to make mold; a special alloy was used to inoculate the molten steel, and proper heat treatment was used to further improve mechanical properties of wear resistant ring-hammers. The influence of this new production technology on the microstructure and mechanical properties of wear resistant ring-hammers was studied. Results show that iron sand molding, having the inherent characteristic of sand molding, changes the type of metallic compounds, refines crystal grains and increases the fineness of microstructure. Practical experience verified that the properties of the ring-hammers produced with this new technique are as follows: tensile strength (Rm 720 MPa, impact toughness (ak > 210 J•cm-2 and hardness > 200 HB. After water quenching from 1,080℃ (holding for 4 h and tempering at 320℃ for 3 h, the best wear resistance is obtained, and the wear resistance is 1.6 times higher than that of common high manganese ring-hammers.

A comprehensive review of an unmet public health issue: resistant hypertension.

Science.gov (United States)

Cai, Anping; Feng, Yingqing; Zhou, Yingling

2017-01-01

Resistant hypertension is an intractable problem to patients and physicians. In recent decades, a substantial amount of basic and epidemiological studies provide us a vast number of valuable evidence and information about this once elusive disease. Better understanding about this entity could help physicians improve diagnostic and therapeutic accuracy. In present review, therefore, we first will detail the definition and diagnosis of resistant hypertension between cardiology societies, and followed by the information of prevalence of resistant hypertension around the world, and then briefly discuss currently used different nomenclature of resistant hypertension, and finally present diagnostic and therapeutic strategies of resistant hypertension.

Incidence, distribution, and spread of tetracycline resistance determinants and integron-associated antibiotic resistance genes among motile aeromonads from a fish farming environment

DEFF Research Database (Denmark)

Schmidt, Anja S.; Bruun, Morten Sichlau; Dalsgaard, Inger

2001-01-01

. Microbiol. 66:4908-4915, 2000), the predominant resistance phenotype (37%) being a combined oxytetracycline (OTC) and sulphadiazine/trimethoprim resistance. Combined sulphonamide/trimethoprim resistance (135 isolates) appeared closely related to the presence of a class 1 integron (141 strains). Among...

Electrical resistivity measurements to predict abrasion resistance

Indian Academy of Sciences (India)

Home; Journals; Bulletin of Materials Science; Volume 31; Issue 2. Electrical resistivity measurements to predict abrasion resistance of rock aggregates ... It was seen that correlation coefficients were increased for the rock classes. In addition ...

In vitro decomposition of Sphagnum by some microfungi resembles white rot of wood.

Science.gov (United States)

Rice, Adrianne V; Tsuneda, Akihiko; Currah, Randolph S

2006-06-01

The abilities of some ascomycetes (Myxotrichaceae) from a Sphagnum bog in Alberta to degrade cellulose, phenolics, and Sphagnum tissue were compared with those of two basidiomycetes. Most Myxotrichaceae degraded cellulose and tannic acid, and removed cell-wall components simultaneously from Sphagnum tissues, whereas the basidiomycetes degraded cellulose and insoluble phenolics, and preferentially removed the polyphenolic matrix from Sphagnum cell walls. Mass losses from Sphagnum varied from up to 50% for some ascomycetes to a maximum of 35% for the basidiomycetes. The decomposition of Sphagnum by the Myxotrichaceae was analogous to the white rot of wood and indicates that these fungi have the potential to cause significant mineralization of carbon in bogs.

Rapid emergence of a ceftazidime-resistant Burkholderia multivorans strain in a cystic fibrosis patient.

Science.gov (United States)

Stokell, Joshua R; Gharaibeh, Raad Z; Steck, Todd R

2013-12-01

Burkholderia multivorans poses a serious health threat to cystic fibrosis patients due to innate resistance to multiple antibiotics and acquisition of resistance to a range of antibiotics due to the frequent use of antibiotics to treat chronic infections. Monitoring antibiotic susceptibility is crucial to managing patient care. We identified the rapid emergence of a ceftazidime-resistant strain in a single patient within four days during a hospitalization for treatment of an exacerbation. B. multivorans was isolated from expectorated sputum samples using Burkholderia cepacia selective agar. A macrodilution assay was performed on all isolates to determine the minimum inhibitory concentration of ceftazidime. Approximately 4000 colonies were scored to identify the percent of ceftazidime-resistant colonies. Extracted DNA was used to determine the total bacterial counts and abundance of B. multivorans using quantitative PCR. An increase from no detectable B. multivorans ceftazidime-resistant colonies to over 75% of all colonies tested occurred within a four-day period. The resistant population remained dominant in 6 of the 8 samples in the following 17 months of the study. qPCR revealed an association between change in the percent of resistant colonies and abundance of B. multivorans, but not of total bacteria. No association was found between the acquisition of resistance to ceftazidime and other antibiotics commonly used to treat B. multivorans infections. The rapid emergence of a ceftazidime-resistant by B. multivorans strain occurred during a hospitalization while under selective pressure of antibiotics. The resistant strain maintained dominance in the B. multivorans population which resulted in an overall decline in a patient health and treatment efficacy. Copyright © 2013 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

EMERGING ANTIMICROBIAL RESISTANCE IN HOSPITAL A THREAT TO PUBLIC HEALTH

Directory of Open Access Journals (Sweden)

Vichal Rastogi

2013-01-01

Full Text Available Background: Antimicrobial resistance(AMR threatens the health of many throughout the world, since both old and new infectious diseases remain a formidable public health threat. When pathogenic microorganisms can multiply beyond some critical mass in the face of invading antimicrobials, treatment outcome is compromised. This phenomenon is referred as antimicrobial resistance (AMR. Objective: This retrospective study was conducted to assess the overall antimicrobial resistance in bacterial isolates from tertiary care hospitals as majority of patients here receive empirical antibiotics therapy. Method: This retrospective study was carried out in teaching hospital, Greater Noida to determine prevalence of multidrug resistance in patients in relation to empirical antibiotic therapy in hospital. Various samples (pus,urine,blood were collected for bacterial culture and antibiotic sensitivity. Results: Total 500 bacterial strains isolated from ICU, surgery, obstetrics & gynaecology and orthopaedics and their sensitivity pattern was compared in this study. The highest number of resistant bacterias were of pseudomonas sp. i.e. 21(33.87% followed by 16(25.80% of staphylococcus aureus, 12(19.35% of Escherichia coli, Klebseilla sp & Proteus vulgaris were 05(8.06% each & Citrobacter sp. 03(4.83%. Total 62(12.4% bacterial isolates were found to be resistant to multiple drugs. The 31 (50% of these resistant bacteria were prevalent in ICU, 12(19.35% in Surgery, 11(17.74% in Gynaecology, 08(12.90% in Orthopaedics.. All the bacterial strains were resistant to common antibiotics like Penicillin, Amoxicillin, Doxycycline & Cotrimoxazole and some were even resistant to Imipenem. Conclusion: Therefore we have outlined the nature of the antimicrobial resistance problem as an important health issue for national and international community. It is advised to avoid use of empirical antibiotics therapy.

Transgenic crops with an improved resistance to biotic stresses. A review

Directory of Open Access Journals (Sweden)

Tohidfar, M.

2015-01-01

Full Text Available Introduction. Pests, diseases and weeds (biotic stresses are significant limiting factors for crop yield and production. However, the limitations associated with conventional breeding methods necessitated the development of alternative methods for improving new varieties with higher resistance to biotic stresses. Molecular techniques have developed applicable methods for genetic transformation of a wide range of plants. Genetic engineering approach has been demonstrated to provide enormous options for the selection of the resistance genes from different sources to introduce them into plants to provide resistance against different biotic stresses. Literature. In this review, we focus on strategies to achieve the above mentioned objectives including expression of insecticidal, antifungal, antibacterial, antiviral resistance and herbicide detoxification for herbicide resistance. Conclusion. Regardless of the concerns about commercialization of products from genetically modified (GM crops resistant to biotic stresses, it is observed that the cultivation area of these crops is growing fast each year. Considering this trend, it is expected that production and commercialization of GM crops resistant to biotic stresses will continue to increase but will also extend to production of crops resistant to abiotic stresses (e.g. drought, salinity, etc. in a near future.

Antibiotic resistance determinants in a Pseudomonas putida strain isolated from a hospital.

Directory of Open Access Journals (Sweden)

Lázaro Molina

Full Text Available Environmental microbes harbor an enormous pool of antibiotic and biocide resistance genes that can impact the resistance profiles of animal and human pathogens via horizontal gene transfer. Pseudomonas putida strains are ubiquitous in soil and water but have been seldom isolated from humans. We have established a collection of P. putida strains isolated from in-patients in different hospitals in France. One of the isolated strains (HB3267 kills insects and is resistant to the majority of the antibiotics used in laboratories and hospitals, including aminoglycosides, ß-lactams, cationic peptides, chromoprotein enediyne antibiotics, dihydrofolate reductase inhibitors, fluoroquinolones and quinolones, glycopeptide antibiotics, macrolides, polyketides and sulfonamides. Similar to other P. putida clinical isolates the strain was sensitive to amikacin. To shed light on the broad pattern of antibiotic resistance, which is rarely found in clinical isolates of this species, the genome of this strain was sequenced and analysed. The study revealed that the determinants of multiple resistance are both chromosomally-borne as well as located on the pPC9 plasmid. Further analysis indicated that pPC9 has recruited antibiotic and biocide resistance genes from environmental microorganisms as well as from opportunistic and true human pathogens. The pPC9 plasmid is not self-transmissible, but can be mobilized by other bacterial plasmids making it capable of spreading antibiotic resistant determinants to new hosts.

A wheat cold resistance mutant derived from space mutagenesis

International Nuclear Information System (INIS)

Li Peng; Sun Mingzhu; Zhang Fengyun; Gao Guoqiang; Qiu Denglin; Li Xinhua

2012-01-01

A cold resistance mutant, obtained by spaceflight mutagenesis on the seeds of wheat variety Han6172, and the DNA of cold resistance mutant and contrast Han6172 were compared by SRAP technique. 380 pairs of primers were screened, 6 pairs of them had polymorphisms between mutant and contrast, the rate was 1.58%, and this data indicated that there are no obvious DNA differences between mutant and contrast Six specific fragments were obtained, 3 fragments of them were amplified in mutant. Homology analysis in GenBank showed that Me3-Em7-Mt, Me4-Em11-CK, Me7-Em19-CK and Me6-Em9-Mt all had homologous sequences with wheat chromosome 3B-specific BAC library, and this result indicated that the gene and regulator sequences associated with mutant cold resistance might locate on 3B chromosome. It was speculated that space mutation induced the mutation of 3B chromosome primary structure, and influenced the expressions of cold resistance genes, which resulted in the mutation of cold resistance ability. (authors)

A wheat cold resistance mutant derived from space mutagenesis

International Nuclear Information System (INIS)

Li Peng; Sun Mingzhu; Zhang Fengyun; Gao Guoqiang; Qiu Denglin; Li Xinhua

2011-01-01

A cold resistance mutant, obtained by spaceflight mutagenesis on the seeds of wheat variety Han6172, and the DNA of cold resistance mutant and contrast Han6172 were compared by SRAP technique. 380 pairs of primers were screened, 6 pairs of them had polymorphisms between mutant and contrast, the rate was 1.58%, and this data indicated that there are no obvious DNA differences between mutant and contrast. Six specific fragments were obtained, 3 fragments of them were amplified in mutant. Homology analysis in GenBank showed that Me3-Em7-Mt, Me4-Em11-CK, Me7-Em19-CK and Me6-Em9-Mt all had homologous sequences with wheat chromosome 3B-specific BAC library, and this result indicated that the gene and regulator sequences associated with mutant cold resistance might locate on 3B chromosome. It was speculated that space mutation induced the mutation of 3B chromosome primary structure, and influenced the expressions of cold resistance genes, which resulted in the mutation of cold resistance ability. (authors)

RESISTANT HYPERTENSION IN A PATIENT WITH METABOLIC SYNDROME

OpenAIRE

O. M. Drapkina; J. S. Sibgatullina

2016-01-01

Clinical case of resistant hypertension in a patient with metabolic syndrome is presented. Features of hypertension in metabolic syndrome and features of metabolic syndrome in women of pre- and postmenopausal age are also considered. Understanding the features of metabolic syndrome in women, as well as features of hypertension and metabolic syndrome will improve the results of treatment in patients with resistant hypertension.

Use of and microbial resistance to antibiotics in China: a path to reducing antimicrobial resistance.

Science.gov (United States)

Cui, Dan; Liu, Xinliang; Hawkey, Peter; Li, Hao; Wang, Quan; Mao, Zongfu; Sun, Jing

2017-12-01

We analyzed China's current use of and microbial resistance to antibiotics, and possible means of reducing antimicrobial resistance. Interventions like executive orders within clinical settings and educational approach with vertical approaches rather than an integrated strategy to curb the use of antimicrobials remain limited. An underlying problem is the system of incentives that has resulted in the intensification of inappropriate use by health professionals and patients. There is an urgent need to explore the relationship between financial and non-financial incentives for providers and patients, to eliminate inappropriate incentives. China's national health reforms have created an opportunity to contain inappropriate use of antibiotics through more comprehensive and integrated strategies. Containment of microbial resistance may be achieved by strengthening surveillance at national, regional and hospital levels; eliminating detrimental incentives within the health system; and changing prescribing behaviors to a wider health systems approach, to achieve long-term, equitable and sustainable results and coordinate stakeholders' actions through transparent sharing of information.

Resistance Training in Children and Young Adults: A Critical Review

Directory of Open Access Journals (Sweden)

Rami Shenouda

2017-01-01

Full Text Available Resistance training is a method used by many athletes to increase their levels of performance. The benefits of this method are known to be increased strength, power and endurance. Resistance training in children has been a topic that has been long debated and there are some widely accepted beliefs and principles that guide clinicians involved in the discipline of sport and exercise medicine. While weight training is a form of resistance training that has proven beneficial effects on health and wellbeing, powerlifting and heavy weight training should be avoided, as lifting maximal weights through various ranges of motion as fast as possible can lead to serious limb injuries. In order to determine the risks and benefits of resistance training in children and adolescents, it is important to review the literature to find a clear consensus. Further prospective research should be completed to determine the long-term sequelae of resistance training in children in comparison to the general population.

Antibody-Mediated Extreme Insulin Resistance: A Report of Three Cases.

Science.gov (United States)

Kim, Han Na; Fesseha, Betiel; Anzaldi, Laura; Tsao, Allison; Galiatsatos, Panagis; Sidhaye, Aniket

2018-01-01

Type 2 diabetes mellitus is characterized by relative insulin deficiency and insulin resistance. Features suggesting severe insulin resistance include acanthosis nigricans, hyperandrogenism, weight loss, and recurrent hospital admissions for diabetic ketoacidosis. In rare circumstances, hyperglycemia persists despite administration of massive doses of insulin. In these cases, it is important to consider autoimmune etiologies for insulin resistance, such as type B insulin resistance and insulin antibody-mediated extreme insulin resistance, which carry high morbidity and mortality if untreated. Encouragingly, immunomodulatory regimens have recently been published that induce remission at high rates. We describe 3 cases of extreme insulin resistance mediated by anti-insulin receptor autoantibodies or insulin autoantibodies. All cases were effectively treated with an immunomodulatory regimen. Although cases of extreme insulin resistance are rare, it is important to be aware of autoimmune causes, recognize suggestive signs and symptoms, and pursue appropriate diagnostic evaluation. Prompt treatment with immunomodulators is key to restoring euglycemia in patients with autoimmune etiologies of insulin resistance. Copyright © 2018 Elsevier Inc. All rights reserved.

Carbohydrate-active enzymes from the zygomycete fungus Rhizopus oryzae: a highly specialized approach to carbohydrate degradation depicted at genome level

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Henrissat Bernard

2011-01-01

Full Text Available Abstract Background Rhizopus oryzae is a zygomycete filamentous fungus, well-known as a saprobe ubiquitous in soil and as a pathogenic/spoilage fungus, causing Rhizopus rot and mucomycoses. Results Carbohydrate Active enzyme (CAZy annotation of the R. oryzae identified, in contrast to other filamentous fungi, a low number of glycoside hydrolases (GHs and a high number of glycosyl transferases (GTs and carbohydrate esterases (CEs. A detailed analysis of CAZy families, supported by growth data, demonstrates highly specialized plant and fungal cell wall degrading abilities distinct from ascomycetes and basidiomycetes. The specific genomic and growth features for degradation of easily digestible plant cell wall mono- and polysaccharides (starch, galactomannan, unbranched pectin, hexose sugars, chitin, chitosan, β-1,3-glucan and fungal cell wall fractions suggest specific adaptations of R. oryzae to its environment. Conclusions CAZy analyses of the genome of the zygomycete fungus R. oryzae and comparison to ascomycetes and basidiomycete species revealed how evolution has shaped its genetic content with respect to carbohydrate degradation, after divergence from the Ascomycota and Basidiomycota.

Characterization of a stable, metronidazole-resistant Clostridium difficile clinical isolate.

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Tarah Lynch

Full Text Available BACKGROUND: Clostridium difficile are gram-positive, spore forming anaerobic bacteria that are the leading cause of healthcare-associated diarrhea, usually associated with antibiotic usage. Metronidazole is currently the first-line treatment for mild to moderate C. difficile diarrhea however recurrence occurs at rates of 15-35%. There are few reports of C. difficile metronidazole resistance in the literature, and when observed, the phenotype has been transient and lost after storage or exposure of the bacteria to freeze/thaw cycles. Owing to the unstable nature of the resistance phenotype in the laboratory, clinical significance and understanding of the resistance mechanisms is lacking. METHODOLOGY/PRINCIPAL FINDINGS: Genotypic and phenotypic characterization was performed on a metronidazole resistant clinical isolate of C. difficile. Whole-genome sequencing was used to identify potential genetic contributions to the phenotypic variation observed with molecular and bacteriological techniques. Phenotypic observations of the metronidazole resistant strain revealed aberrant growth in broth and elongated cell morphology relative to a metronidazole-susceptible, wild type NAP1 strain. Comparative genomic analysis revealed single nucleotide polymorphism (SNP level variation within genes affecting core metabolic pathways such as electron transport, iron utilization and energy production. CONCLUSIONS/SIGNIFICANCE: This is the first characterization of stable, metronidazole resistance in a C. difficile isolate. The study provides an in-depth genomic and phenotypic analysis of this strain and provides a foundation for future studies to elucidate mechanisms conferring metronidazole resistance in C. difficile that have not been previously described.

KTA 625 alloy tube with excellent corrosion resistance and heat resistance

International Nuclear Information System (INIS)

Fujiwara, Kazuo; Kadonaga, Toshiki; Kikuma, Seiji.

1982-01-01

The problems when seamless tubes are produced by using nickel base 625 alloy (61Ni-22Cr-9Mo-Cb) which is known as a corrosion resistant and heat resistant alloyF were examined, and the confirmation experiment was carried out on its corrosion resistance and heat resistance. Various difficulties have been experienced in the tube making owing to the characteristics due to the chemical composition, but they were able to be solved by the repeated experiments. As for the characteristics of the product, the corrosion resistance was excellent particularly in the environment containing high temperature, high concentration chloride, and also the heat resistance was excellent in the wide temperature range from normal temperature to 1000 deg C. From these facts, the wide fields of application are expected for these alloy tubes, including the evaporation and concentration equipment for radioactive wastes in atomic energy field. Expecting the increase of demand hereafter, Kobe Steel Ltd. examined the problems when seamless tubes are produced from the 625 alloy by Ugine Sejournet process. The aptitude for tube production such as the chemical composition, production process and the product characteristics, the corrosion resistance against chloride, hydrogen sulfide, polythionic and other acids,F the high temperature strength and oxidation resistance are reported. (Kako, I.)

Antimicrobial resistance in Danish pigs: A cross sectional study of the association between antimicrobial resistance and geography, exposure to antimicrobials, and trade

DEFF Research Database (Denmark)

Birkegård, Anna Camilla

Antimicrobial resistance is a worldwide problem of paramount importance for both humans and animals. To combat the emergence of antimicrobial resistance, the problem must be targeted in all major reservoirs as it is assumed that a high level of AMR genes in environmental reservoirs can increase...... the risk of human pathogens becoming resistant. Pigs might constitute an important reservoir. Therefore, it is important to manage antimicrobial resistance in pigs. Before effectiveactions can be initiated, it is crucial to know which factors are associated with the levels of antimicrobial resistance...... the collection of information on relevant factors. The aim of this PhD project was to study the relationship between the levels of antimicrobial resistance genes and three factors in Danish pig farms: the geographical location of the farm, the exposure to antimicrobials, and the trade patterns. Data collection...

Neratinib resistance and cross-resistance to other HER2-targeted drugs due to increased activity of metabolism enzyme cytochrome P4503A4

OpenAIRE

Breslin, Susan; Lowry, Michelle C; O'Driscoll, Lorraine

2017-01-01

Background: Neratinib is in Phase 3 clinical trials but, unfortunately, the development of resistance is inevitable. Here, we investigated the effects of acquired neratinib resistance on cellular phenotype and the potential mechanism of this resistance. Methods: Neratinib-resistant variants of HER2-positive breast cancer cells were developed and their cross-resistance investigated using cytotoxicity assays. Similarly, sensitivity of trastuzumab-resistant and lapatinib-resistant cells to nerat...

FARME DB: a functional antibiotic resistance element database

OpenAIRE

Wallace, James C.; Port, Jesse A.; Smith, Marissa N.; Faustman, Elaine M.

2017-01-01

Antibiotic resistance (AR) is a major global public health threat but few resources exist that catalog AR genes outside of a clinical context. Current AR sequence databases are assembled almost exclusively from genomic sequences derived from clinical bacterial isolates and thus do not include many microbial sequences derived from environmental samples that confer resistance in functional metagenomic studies. These environmental metagenomic sequences often show little or no similarity to AR se...

Emergence of multidrug-resistant, extensively drug-resistant and untreatable gonorrhea

Science.gov (United States)

Unemo, Magnus; Nicholas, Robert A

2013-01-01

The new superbug Neisseria gonorrhoeae has retained resistance to antimicrobials previously recommended for first-line treatment and has now demonstrated its capacity to develop resistance to the extended-spectrum cephalosporin, ceftriaxone, the last remaining option for first-line empiric treatment of gonorrhea. An era of untreatable gonorrhea may be approaching, which represents an exceedingly serious public health problem. Herein, we review the evolution, origin and spread of antimicrobial resistance and resistance determinants (with a focus on extended-spectrum cephalosporins) in N. gonorrhoeae, detail the current situation regarding verified treatment failures with extended-spectrum cephalosporins and future treatment options, and highlight essential actions to meet the large public health challenge that arises with the possible emergence of untreatable gonorrhea. Essential actions include: implementing action/response plans globally and nationally; enhancing surveillance of gonococcal antimicrobial resistance, treatment failures and antimicrobial use/misuse; and improving prevention, early diagnosis and treatment of gonorrhea. Novel treatment strategies, antimicrobials (or other compounds) and, ideally, a vaccine must be developed. PMID:23231489

Resistance to Wheat Curl Mite in Arthropod-Resistant Rye-Wheat Translocation Lines

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Lina Maria Aguirre-Rojas

2017-11-01

Full Text Available The wheat curl mite, Aceria toschiella (Keifer, and a complex of viruses vectored by A. toschiella substantially reduce wheat yields in every wheat-producing continent in the world. The development of A. toschiella-resistant wheat cultivars is a proven economically and ecologically viable method of controlling this pest. This study assessed A. toschiella resistance in wheat genotypes containing the H13, H21, H25, H26, H18 and Hdic genes for resistance to the Hessian fly, Mayetiola destructor (Say and in 94M370 wheat, which contains the Dn7 gene for resistance to the Russian wheat aphid, Diuraphis noxia (Kurdjumov. A. toschiella populations produced on plants containing Dn7 and H21 were significantly lower than those on plants of the susceptible control and no different than those on the resistant control. Dn7 resistance to D. noxia and H21 resistance to M. destructor resulted from translocations of chromatin from rye into wheat (H21—2BS/2RL, Dn7—1BL/1RS. These results provide new wheat pest management information, indicating that Dn7 and H21 constitute resources that can be used to reduce yield losses caused by A. toschiella, M. destructor, D. noxia, and wheat streak mosaic virus infection by transferring multi-pest resistance to single sources of germplasm.

Genetic Determinants of High-Level Oxacillin Resistance in Methicillin-Resistant Staphylococcus aureus.

Science.gov (United States)

Pardos de la Gandara, Maria; Borges, Vitor; Chung, Marilyn; Milheiriço, Catarina; Gomes, João Paulo; de Lencastre, Herminia; Tomasz, Alexander

2018-06-01

Methicillin-resistant Staphylococcus aureus (MRSA) strains carry either a mecA - or a mecC -mediated mechanism of resistance to beta-lactam antibiotics, and the phenotypic expression of resistance shows extensive strain-to-strain variation. In recent communications, we identified the genetic determinants associated with the stringent stress response that play a major role in the antibiotic resistant phenotype of the historically earliest "archaic" clone of MRSA and in the mecC -carrying MRSA strain LGA251. Here, we sought to test whether or not the same genetic determinants also contribute to the resistant phenotype of highly and homogeneously resistant (H*R) derivatives of a major contemporary MRSA clone, USA300. We found that the resistance phenotype was linked to six genes ( fruB , gmk , hpt , purB , prsA , and relA ), which were most frequently targeted among the analyzed 20 H*R strains (one mutation per clone in 19 of the 20 H*R strains). Besides the strong parallels with our previous findings (five of the six genes matched), all but one of the repeatedly targeted genes were found to be linked to guanine metabolism, pointing to the key role that this pathway plays in defining the level of antibiotic resistance independent of the clonal type of MRSA. Copyright © 2018 American Society for Microbiology.

Recessive Resistance to Plant Viruses: Potential Resistance Genes Beyond Translation Initiation Factors

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Masayoshi Hashimoto

2016-10-01

Full Text Available The ability of plant viruses to propagate their genomes in host cells depends on many host factors. In the absence of an agrochemical that specifically targets plant viral infection cycles, one of the most effective methods for controlling viral diseases in plants is taking advantage of the host plant’s resistance machinery. Recessive resistance is conferred by a recessive gene mutation that encodes a host factor critical for viral infection. It is a branch of the resistance machinery and, as an inherited characteristic, is very durable. Moreover, recessive resistance may be acquired by a deficiency in a negative regulator of plant defense responses, possibly due to the autoactivation of defense signaling. Eukaryotic translation initiation factor (eIF 4E and eIF4G and their isoforms are the most widely exploited recessive resistance genes in several crop species, and they are effective against a subset of viral species. However, the establishment of efficient, recessive resistance-type antiviral control strategies against a wider range of plant viral diseases requires genetic resources other than eIF4Es. In this review, we focus on recent advances related to antiviral recessive resistance genes evaluated in model plants and several crop species. We also address the roles of next-generation sequencing and genome editing technologies in improving plant genetic resources for recessive resistance-based antiviral breeding in various crop species.

Mechanism of mercuric chloride resistance in microorganisms. I. Vaporization of a mercury compound from mercuric chloride by multiple drug resistant strains of Escherichia coli

Energy Technology Data Exchange (ETDEWEB)

Komura, I; Izaki, K

1971-01-01

Three strains of Escherichia coli possessing the multiple drug resistance were found to be resistant also to HgCl/sub 2/, though they were sensitive to other heavy metal ions such as nickel, cobalt, cadmium and zinc ions. Like the resistance to drugs such as chloramphenicol and tetracycline, the HgCl/sub 2/ resistance could be transferred from a resistant strain of E. coli to sensitive strains of E. coli and Aerobacter aerogenes. The resistant strains could grow in the presence of 0.02 mM HgCl/sub 2/, whereas a sensitive strain failed to grow in the presence of 0.01 mM HgCl/sub 2/. During cultivation in the presence of HgCl/sub 2/, the cells of resistant strain vaporized a form of radioactive mercury when incubated with /sup 203/HgCl/sub 2/, glucose and NaCl in phosphate buffer while the cells of sensitive strain showed no such activity. This phenomenon seemed to explain the HgCl/sub 2/ resistance of the resistant strains.

Outbreak of carbapenem-resistant Providencia rettgeri in a tertiary ...

African Journals Online (AJOL)

Carbapenem resistance in Enterobacteriaceae is often plasmid mediated, necessitating stringent infection control practices. We describe an outbreak of carbapenem-resistant Providencia rettgeri involving 4 patients admitted to intensive care and high-care units at a tertiary hospital. Clinical and demographic characteristics ...

A pulse-tube refrigerator using variable-resistance orifice

Science.gov (United States)

Huang, B. J.; Sun, B. W.

2003-01-01

In the present study, we propose a new design of orifice pulse-tube refrigerator (VROPT) using a variable-resistance valve to replace the conventional orifice. The variable-resistance orifice (VRO) is basically a high-speed solenoidal valve similar to the fuel jet device widely used in automobile engines. By changing the frequency and periods of ON and OFF of the valve through an electronic device, we can change the flow resistance of the VRO. This thus provides a possibility for an OPT to be controlled on-line during operation. From the results obtained in the present study, we have shown that VROPT is able to achieve on-line control by regulating the duty cycle d or frequency fv of the VRO. We also show that VROPT will not loss its thermal performance as compared to conventional OPT.

A review of mechanisms of circumvention and modulation of chemotherapeutic drug resistance.

Science.gov (United States)

O'Connor, R

2009-05-01

Drug resistance is a serious limitation to the effective treatment of a number of common malignancies. Thirty years of laboratory and clinical research have greatly defined the molecular alterations underlying many drug resistance processes in cancer. Based on this knowledge, strategies to overcome the impact of resistance and increase the efficacy of cancer treatment have been translated from laboratory models to clinical trials. This article reviews laboratory and, in particular, clinical attempts at drug resistance circumvention from early forays in the inhibition of cellular efflux pump-mediated drug resistance through to more selective circumvention agent strategies and into inhibition of the other important mechanisms which can allow cancer cells to survive therapy, such as apoptosis resistance. Despite some promising results to date, resistance inhibition strategies have largely failed due to poor understanding of the pharmacology, dynamics and complexity of the resistance phenotype. With the realisation that new molecularly-targeted agents can also be rendered ineffectual by the actions of resistance mechanisms, a major focus is once again emerging on identifying new strategies/pharmaceuticals which can augment the activity of the arsenal of more conventional cytotoxics and newer targeted anti-cancer drugs. Future tactical directions where old and new resistance strategies may merge to overcome this challenge are discussed.

Diagnostic Evasion of Highly-Resistant Microorganisms: A Critical Factor in Nosocomial Outbreaks.

Science.gov (United States)

Zhou, Xuewei; Friedrich, Alexander W; Bathoorn, Erik

2017-01-01

Highly resistant microorganisms (HRMOs) may evade screening strategies used in routine diagnostics. Bacteria that have evolved to evade diagnostic tests may have a selective advantage in the nosocomial environment. Evasion of resistance detection can result from the following mechanisms: low-level expression of resistance genes not resulting in detectable resistance, slow growing variants, mimicry of wild-type-resistance, and resistance mechanisms that are only detected if induced by antibiotic pressure. We reviewed reports on hospital outbreaks in the Netherlands over the past 5 years. Remarkably, many outbreaks including major nation-wide outbreaks were caused by microorganisms able to evade resistance detection by diagnostic screening tests. We describe various examples of diagnostic evasion by several HRMOs and discuss this in a broad and international perspective. The epidemiology of hospital-associated bacteria may strongly be affected by diagnostic screening strategies. This may result in an increasing reservoir of resistance genes in hospital populations that is unnoticed. The resistance elements may horizontally transfer to hosts with systems for high-level expression, resulting in a clinically significant resistance problem. We advise to communicate the identification of HRMOs that evade diagnostics within national and regional networks. Such signaling networks may prevent inter-hospital outbreaks, and allow collaborative development of adapted diagnostic tests.

Antibiotic Resistance in Foodborne Pathogens

OpenAIRE

Walsh, Ciara; Duffy, Geraldine

2013-01-01

Wide-spread antibiotic resistance among bacterial pathogens is now a serious public health issue and multi-antibiotic resistance has been reported in many foodborne pathogens including Salmonella and E. coli. A study to determine antibiotic resistance profiles of a range of Salmonella and Verocytotoxigenic E.coli (VTEC) isolated from Irish foods revealed significant levels of antibiotic resistance in the strains. S. typhimurium DT104 were multiantibiotic resistant with 97% resistant to 7 anti...

Anthelmintic resistance in a herd of alpacas (Vicugna pacos)

Science.gov (United States)

Galvan, Noe; Middleton, John R.; Nagy, Dusty W.; Schultz, Loren G.; Schaeffer, Josh W.

2012-01-01

A herd of alpacas was examined because of a history of severe endoparasitism, anemia, hypoproteinemia, and weight loss. Resistance of gastrointestinal nematodes to albendazole, fenbendazole, and doramectin was documented. This report suggests that anthelmintic resistance may be an emerging problem in South American camelids in North America. PMID:23729829

Resistance to valproic acid as predictor of treatment resistance in genetic generalized epilepsies

DEFF Research Database (Denmark)

Gesche, Joanna; Khanevski, Marina; Solberg, Carl