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Sample records for orobanche crenata resistance

  1. Variation in the resistance of some faba bean genotypes to orobanche crenata

    International Nuclear Information System (INIS)

    Abbes, Z.; Sellami, F.; Amri, M.; Kharrat, M.

    2011-01-01

    Four faba bean (Vicia faba L.) genotypes were tested for their reaction to Orobanche crenata Forsk., infestation. Evaluation was carried out for two cropping seasons at the Ariana research station, Tunisia in a field naturally infested with O. crenata and in pot experiments. At maturity, the genotypes Baraca, Giza 429 and the breeding line Bader carried 2-6 times less of number of emerged parasites and 3-7 less of dry weight of emerged parasites than the susceptible cv. Bader. The average yield observed for the three resistant genotypes was two to four-fold higher than the one observed for the susceptible genotype. These resistant genotypes seemed to flower earlier and to show late orobanche establishment which gave them an advantage over the parasite. The genotype Bader, which was selected for its resistance to O. foetida, was resistant to O. crenata, showing that selecting for O. foetida resistance can protect against O. crenata infection. Besides, the two genotypes Baraca and Giza 429 selected for their resistance to O. crenata in Spain and Egypt respectively, do not present tubercle necrosis on their roots, showing that they do not respond similarly to the Tunisian population of O. crenata. These partially resistant genotypes may provide breeders with additional sources of resistance to O. crenata, and can form appropriate material for an integrated control package. (author)

  2. Mucilage production during the incompatible interaction between Orobanche crenata and Vicia sativa.

    Science.gov (United States)

    Pérez-de-Luque, Alejandro; Lozano, M Dolores; Cubero, José I; González-Melendi, Pablo; Risueño, M Carmen; Rubiales, Diego

    2006-01-01

    Orobanche spp. (broomrapes) are holoparasites lacking in chlorophyll and totally dependent on their host for their supply of nutrients. O. crenata is a severe constraint to legumes cultivation and breeding for resistance remains as one of the best available methods of control. However, little is known about the basis of host resistance to broomrapes. It is a multicomponent event, and resistance based on hampering development and necrosis of broomrape tubercles has been reported. In the present work, the formation of mucilage and occlusion of host xylem vessels associated with the death of O. crenata tubercles were studied histologically. Samples of necrotic O. crenata tubercles established on resistant and susceptible vetch genotypes were collected. The samples were fixed, sectioned and stained using different procedures. The sections were observed at the light microscopy level, either under bright field, epi-fluorescence or confocal laser scanning microscopy. A higher proportion of necrotic tubercles was found on the resistant genotype and this was associated with a higher percentage of occluded vessels. Mucilage is composed mainly by carbohydrates (non-esterified pectins) and the presence of polyphenols was also detected. The mucilage and other substances composed by parasite secretions and host-degraded products was found to block host vessels and obstruct the parasite supply channel, being a quantitative defensive response against O. crenata in vetch, and probably also in other legumes and plants. The presence of foreign substances (i.e. parasite secretions) and host-degraded products (i.e. carbohydrates from cell walls) inside host vessels seems to activate this response and leads to xylem occlusion and further death of established Orobanche tubercles.

  3. Sucrose effect on broomrape (Orobanche crenata) development on ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-07-06

    Jul 6, 2009 ... Key words: Sucrose, Orobanche crenata, Vicia narbonensis and broomrape control. INTRODUCTION ... and forage legume used for livestock feed in the .... the yield of faba bean significantly (Kukula and Masri, 1984). More-.

  4. Protein cross-linking, peroxidase and beta-1,3-endoglucanase involved in resistance of pea against Orobanche crenata.

    Science.gov (United States)

    Pérez-de-Luque, Alejandro; González-Verdejo, Clara I; Lozano, M Dolores; Dita, Miguel A; Cubero, José I; González-Melendi, Pablo; Risueño, María C; Rubiales, Diego

    2006-01-01

    Root holoparasitic angiosperms, like Orobanche spp, completely lack chlorophyll and totally depend on their host for their supply of nutrients. O. crenata is a severe constraint to the cultivation of legumes and breeding for resistance remains the most economical, feasible, and environmentally friendly method of control. Due to the lack of resistance in commercial pea cultivars, the use of wild relatives for breeding is necessary, and an understanding of the mechanisms underlying host resistance is needed in order to improve screening for resistance in breeding programmes. Compatible and incompatible interactions between O. crenata and pea have been studied using cytochemical procedures. The parasite was stopped in the host cortex before reaching the central cylinder, and accumulation of H2O2, peroxidases, and callose were detected in neighbouring cells. Protein cross-linking in the host cell walls appears as the mechanism of defence, halting penetration of the parasite. In situ hybridization studies have also shown that a peroxidase and a beta-glucanase are differently expressed in cells of the resistant host (Pf651) near the penetration point. The role of these proteins in the resistance to O. crenata is discussed.

  5. Performance of faba bean genotypes with Orobanche foetida Poir. and Orobanche crenata Forsk. infestation in Tunisia

    Directory of Open Access Journals (Sweden)

    Imen Trabelsi

    2015-03-01

    Full Text Available Orobanche foetida Poir. and O. crenata Forsk. are major constraints to faba bean (Vicia faba L. cultivation in Tunisia. To evalúate the different levels of resistance of seven small-seeded faba bean genotypes to these parasitic weed species, three trials were conducted in fields infested and non-infested with O. foetida in the Oued Beja Agricultural Experimental Unit and O. crenata in an experimental field at Ariana of the National Institute of Agricultural Research during three cropping seasons. Compared to the susceptible cv. Bad'i, the seven genotypes showed moderate to high levels of resistance to both Orobanche species. The number and dry weight of emerged broomrapes and underground tubercles recorded on the new improved genotypes were lower than those recorded on released and resistant 'Najeh' and 'Baraca'. The parasitism index on the new genotypes varied from 2-6 times less than susceptible 'Bad'i' in both Oued-Beja and Ariana. Yield reduction due to O.foetida infection varied from 13.5% on genotype XAR-VF00.13-89-2-1-1-1-1 to 59.7% on 'Baraca', whereas the yield loss was about 92% on the susceptible control. Parasitic infection did not affect dry grain protein accumulation in the tested genotypes.

  6. Interaction between Orobanche crenata and its host legumes: unsuccessful haustorial penetration and necrosis of the developing parasite.

    Science.gov (United States)

    Pérez-DE-Luque, A; Rubiales, D; Cubero, J I; Press, M C; Scholes, J; Yoneyama, K; Takeuchi, Y; Plakhine, D; Joel, D M

    2005-05-01

    Orobanche species represent major constraints to crop production in many parts of the world as they reduce yield and alter root/shoot allometry. Although much is known about the histology and effect of Orobanche spp. on susceptible hosts, less is known about the basis of host resistance to these parasites. In this work, histological aspects related to the resistance of some legumes to Orobanche crenata have been investigated in order to determine which types of resistance responses are involved in the unsuccessful penetration of O. crenata. Samples of resistance reactions against O. crenata on different genotypes of resistant legumes were collected. The samples were fixed, sectioned and stained using different procedures. Sections were observed using a transmission light microscope and by epi-fluorescence. Lignification of endodermal and pericycle host cells seems to prevent parasite intrusion into the root vascular cylinder at early infection stages. But in other cases, established tubercles became necrotic and died. Contrary to some previous studies, it was found that darkening at the infection site in these latter cases does not correspond to death of host tissues, but to the secretion of substances that fill the apoplast in the host-parasite interface and in much of the infected host tissues. The secretions block neighbouring host vessels. This may interfere with the nutrient flux between host and parasite, and may lead to necrosis and death of the developing parasite. The unsuccessful penetration of O. crenata seedlings into legume roots cannot be attributed to cell death in the host. It seems to be associated with lignification of host endodermis and pericycle cells at the penetration site. The accumulation of secretions at the infection site, may lead to the activation of xylem occlusion, another defence mechanism, which may cause further necrosis of established tubercles.

  7. Validation of QTLs for Orobanche crenata resistance in faba bean (Vicia faba L.) across environments and generations.

    Science.gov (United States)

    Díaz-Ruiz, Ramón; Torres, A M; Satovic, Z; Gutierrez, M V; Cubero, J I; Román, Belén

    2010-03-01

    Broomrape (Orobanche crenata Forsk.) is a major root-parasite of faba bean (Vicia faba L.), that seriously limits crop cultivation in the whole Mediterranean area. This parasitic weed is difficult to control, difficult to evaluate and the resistance identified so far is of polygenic nature. This study was conducted to identify genetic regions associated with broomrape resistance in recombinant inbred lines (RILs) and to validate their previous location in the original F(2) population derived from the cross between lines Vf6 and Vf136. A progeny consisting of 165 F(6) RILs was evaluated in three environments across two locations in 2003 and 2004. Two hundred seventy seven molecular markers were assigned to 21 linkage groups (9 of them assigned to specific chromosomes) that covered 2,856.7 cM of the V. faba genome. The composite interval mapping on the F(6) map detected more quantitative trait loci (QTL) than in the F(2) analysis. In this sense, four QTLs controlling O. crenata resistance (Oc2-Oc5) were identified in the RI segregant population in three different environments. Only Oc1, previously reported in the F(2) population, was not significant in the advanced lines. Oc2 and Oc3 were found to be associated with O. crenata resistance in at least two of the three environments, while the remaining two, Oc4 and Oc5, were only detected in Córdoba-04 and Mengíbar-04 and seemed to be environment dependent.

  8. Study of some resistance mechanisms to Orobanche spp. infestation in faba bean (Vicia faba L. breeding lines in Tunisia

    Directory of Open Access Journals (Sweden)

    Imen Trabelsi

    2016-10-01

    Full Text Available The behavior of seven faba bean breeding lines toward Orobanche foetida and Orobanche crenata infestation was examined under field, pots, and in vitro conditions and compared to reference cultivars. The breeding lines presented resistance reaction to Orobanche spp. in different experiment conditions. In infested field by O. foetida, the grain yield reduction ranged from 55.7 to 83% for the breeding lines compared to 97% for the susceptible cultivar Badï. Lines L6 and L7 were the less affected by Orobanche parasitism considering severity, number of emerged Orobanche, and yield. In pots, the number of attachments varied from .6 to 3.4 and from 1.4 to 6.4 for the breeding lines against 10.4 and 12.3 for Badï inoculated, respectively, by O. foetida and O. crenata. In Petri dish experiment, Orobanche germination reached the highest rates; 69.9 and 59.7%, respectively, with O. crenata and O. foetida for Badï. For the breeding lines, it ranged from 6.3 to 44.9% for O. crenata and from 4.8 to 40.8% for O. foetida. Moreover, all breeding lines showed low tubercles number and delay in Orobanche attachments as compared to Badï. All breeding lines, except L5, maintained an acceptable level of resistance to Orobanche species manifested by a reduced Orobanche germination rate, low Orobanche number and dry weight, delay of attachments, and higher grain production compared to Badï. L5 seems to be less resistant even it behaves better than Badï in different culture conditions. The studied breeding lines could be recommended as resistance sources or candidates for varieties registrations.

  9. Gene expression analysis of molecular mechanisms of defense induced in Medicago truncatula parasitized by Orobanche crenata.

    Science.gov (United States)

    Die, José Vicente; González Verdejo, Clara I; Dita, Miguel A; Nadal, Salvador; Román, Belén

    2009-07-01

    The infection of Medicago truncatula Gaertn. roots with the obligate parasite Orobanche crenata Forsk. is a useful model for studying the molecular events involved in the legumes-parasite interaction. In order to gain insight into the identification of gene-regulatory elements involved in the resistance mechanism, the temporal expression pattern of ten defense-related genes was carried out using real-time quantitative reverse-transcription polymerase chain reaction assays. The induction of all of the analyzed transcripts significantly increased over a range from 2- to 321-fold higher than the control depending on the gene and time point. The transcriptional changes observed in response to O. crenata infection suggest that resistance could rely on both, the induction of general defense-related genes and more specific responses.

  10. Mechanisms of protection of pea plants by polysaccharides extracted from a strain of Rhizobium against Orobanche crenata

    International Nuclear Information System (INIS)

    Khairi, Hanene; Temani, Randa

    2009-01-01

    The Broomrape causes notable damage on the leguminous crops and became major factor limiting production of pea in the Mediterranean region. The effect of the polysaccharides extracted from P.SOM Rhizobium strain on the development of Orobanche crenata on pea was studied. The results showed that the lipopolysaccharides significantly reduce the infestation of pea by O. crenata. This limitation of infestation results from the reduction of seeds germination rates of the parasite resulting in reduction of the tubercles number on pea roots. Moreover, necrosis of orobanche before or after attachment on pea roots treated by LPS can explain this reduction of parasitism. A correlation was observed between the reduction of pea infection by the broomrape and the activation phenolic compounds pathway. This activation resulted to increase of two enzymes (peroxidase and polyphenoloxidase) activities these enzymes are implicated in plant defense. The results of our study showed that the LPS seem implied in the induction of pea resistance against the broomrape.

  11. Biological Characteristics and Control of Orobanche Crenata Forsk., a Review

    Directory of Open Access Journals (Sweden)

    Alessia Restuccia

    2009-03-01

    Full Text Available Orobanche crenata is a holoparasitic phanerogam which is particularly noxious to legumes, such as faba bean (Vicia faba L., pea (Pisum sativum L., chickpea (Cicer arietinum L., lentil (Lens culinaris Medik., etc., and commonly considered one of the major causes which has contributed to re-rizing the area designed to their cultivation. After a few brief references on the origin and diffusion of O. crenata, in this work summarises the results of research into biological aspects and control of this species. The information obtained especially concerns seed production, seed viability, seed longevity and dormancy, seed conditioning and germination, parasitism phases, the effects of parasite attacks on host plants and the means of control.

  12. Biological Characteristics and Control of Orobanche Crenata Forsk., a Review

    Directory of Open Access Journals (Sweden)

    Giuseppe Restuccia

    2011-02-01

    Full Text Available Orobanche crenata is a holoparasitic phanerogam which is particularly noxious to legumes, such as faba bean (Vicia faba L., pea (Pisum sativum L., chickpea (Cicer arietinum L., lentil (Lens culinaris Medik., etc., and commonly considered one of the major causes which has contributed to re-rizing the area designed to their cultivation. After a few brief references on the origin and diffusion of O. crenata, in this work summarises the results of research into biological aspects and control of this species. The information obtained especially concerns seed production, seed viability, seed longevity and dormancy, seed conditioning and germination, parasitism phases, the effects of parasite attacks on host plants and the means of control.

  13. Inhibition of Orobanche crenata seed germination and radicle growth by allelochemicals identified in cereals.

    Science.gov (United States)

    Fernández-Aparicio, Mónica; Cimmino, Alessio; Evidente, Antonio; Rubiales, Diego

    2013-10-16

    Orobanche crenata is a parasitic weed that causes severe yield losses in important grain and forage legume crops. Cereals have been reported to inhibit O. crenata parasitism when grown intercropped with susceptible legumes, but the responsible metabolites have not been identified. A number of metabolites have been reported in cereals that have allelopathic properties against weeds, pests, and pathogens. We tested the effect of several allelochemicals identified in cereals on O. crenata seed germination and radicle development. We found that 2-benzoxazolinone, its derivative 6-chloroacetyl-2-benzoxazolinone, and scopoletin significantly inhibited O. crenata seed germination. Benzoxazolinones, l-tryptophan, and coumalic acid caused the stronger inhibition of radicle growth. Also, other metabolites reduced radicle length, this inhibition being dose-dependent. Only scopoletin caused cell necrotic-like darkening in the young radicles. Prospects for their application to parasitic weed management are discussed.

  14. Temperature and water stress during conditioning and incubation phase affecting Orobanche crenata seed germination and radicle growth

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    JUAN eMORAL

    2015-06-01

    Full Text Available Orobanche crenata is a holoparasitic plant that is potentially devastating to crop yield of legume species. Soil temperature and humidity are known to affect seed germination, however, the extent of their influence on germination and radicle growth of those of O. crenata is largely unknown. In this work, we studied the effects of temperature, water potential (Ψt and the type of water stress (matric or osmotic on O. crenata seeds during conditioning and incubation periods. We found that seeds germinated between 5 and 30ºC during both periods, with a maximum around 20ºC. Germination increased with increasing Ψt from -1.2 to 0 MPa during conditioning and incubation periods. Likewise, seed germination increased logarithmically with length of conditioning period until 40 days. The impact of the type of water stress on seed germination was similar, although the radicle growth of seeds under osmotic stress was lower than under matric stress, what could explain the lowest infestation of Orobanche spp. in regions characterized by saline soil. The data in this study will be useful to forecast infection of host roots by O. crenata.

  15. Temperature and water stress during conditioning and incubation phase affecting Orobanche crenata seed germination and radicle growth.

    Science.gov (United States)

    Moral, Juan; Lozano-Baena, María Dolores; Rubiales, Diego

    2015-01-01

    Orobanche crenata is a holoparasitic plant that is potentially devastating to crop yield of legume species. Soil temperature and humidity are known to affect seed germination, however, the extent of their influence on germination and radicle growth of those of O. crenata is largely unknown. In this work, we studied the effects of temperature, water potential (Ψt) and the type of water stress (matric or osmotic) on O. crenata seeds during conditioning and incubation periods. We found that seeds germinated between 5 and 30°C during both periods, with a maximum around 20°C. Germination increased with increasing Ψt from -1.2 to 0 MPa during conditioning and incubation periods. Likewise, seed germination increased logarithmically with length of conditioning period until 40 days. The impact of the type of water stress on seed germination was similar, although the radicle growth of seeds under osmotic stress was lower than under matric stress, what could explain the lowest infestation of Orobanche sp. in regions characterized by saline soil. The data in this study will be useful to forecast infection of host roots by O. crenata.

  16. Trigoxazonane, a monosubstituted trioxazonane from Trigonella foenum-graecum root exudate, inhibits Orobanche crenata seed germination.

    Science.gov (United States)

    Evidente, Antonio; Fernández-Aparicio, Mónica; Andolfi, Anna; Rubiales, Diego; Motta, Andrea

    2007-10-01

    Orobanche crenata is a major threat to grain legume production. Fenugreek (Trigonella foenum-graecum) is an annual legume that has been shown to effectively reduce O. crenata infection when intercropped with grain legumes. In this paper, we point that this can be attributed to allelopathy, through inhibition of the germination of O. crenata by fenugreek root exudates. The main inhibitory metabolite was isolated and characterized. Allelopathy was demonstrated in different bioassays, by inhibition of O. crenata seeds germination both by growing fenugreek and pea plants together (intercropped), and by application of fenugreek root exudates. Fenugreek root exudates were extracted with organic solvent and fractionated giving several fractions, two of which showed moderate (27%) and strong (54%) inhibition of O. crenata seed germination, respectively. The most active metabolite is a new monosubstituted trioxazonane, characterized by spectroscopic methods as the 2-butyl-[1,4,7,2]trioxazonane and named trigoxazonane.

  17. Breeding approaches for crenate broomrape (Orobanche crenata Forsk.) management in pea (Pisum sativum L.).

    Science.gov (United States)

    Rubiales, Diego; Fernández-Aparicio, Monica; Pérez-de-Luque, Alejandro; Castillejo, Mari A; Prats, Elena; Sillero, Josefina C; Rispail, Nicolas; Fondevilla, Sara

    2009-05-01

    Pea cultivation is strongly hampered in Mediterranean and Middle East farming systems by the occurrence of Orobanche crenata Forsk. Strategies of control have been developed, but only marginal successes have been achieved. Most control methods are either unfeasible, uneconomical, hard to achieve or result in incomplete protection. The integration of several control measures is the most desirable strategy. [corrected] Recent developments in control are presented and re-evaluated in light of recent developments in crop breeding and molecular genetics. These developments are placed within a framework that is compatible with current agronomic practices. The current focus in applied breeding is leveraging biotechnological tools to develop more and better markers to speed up the delivery of improved cultivars to the farmer. To date, however, progress in marker development and delivery of useful markers has been slow. The application of knowledge gained from basic genomic research and genetic engineering will contribute to more rapid pea improvement for resistance against O. crenata and/or the herbicide.

  18. Host differentiation and variability of Orobanche crenata populations from legume species in Morocco as revealed by cross-infestation and molecular analysis.

    Science.gov (United States)

    Ennami, Mounia; Briache, Fatima Zahra; Gaboun, Fatima; Abdelwahd, Rabha; Ghaouti, Lamiae; Belqadi, Loubna; Westwood, James; Mentag, Rachid

    2017-08-01

    Orobanche crenata represents a major biotic constraint to production of faba bean and lentil in Morocco. While this parasitic plant attacks both of these crops, the extent to which Orobanche biotypes specialise in parasitising specific crops is unknown. To address this question, we studied O. crenata that grew on different hosts and quantified their host specificity to faba bean and lentil. The virulence of O. crenata populations on each host was investigated through field trials, pot and Petri dishes assays. Genetic diversity of the parasite populations was also assessed through molecular analyses. The two legume species showed distinct patterns of specificity. Faba bean was more susceptible to both O. crenata populations, while the specificity for lentil by lentil-grown O. crenata was evident at the final stage of the parasite life cycle as shown by correspondence factorial analyses. Considerable internal variation (81%) within O. crenata populations parasitising both legume species was observed by molecular analyses, but significant divergence (19%; Ø = 0.189; P = 0.010) among the populations was detected. These results indicate that O. crenata can adapt to specific host species, which is important knowledge when developing integrated pest management practices for parasitic weed control. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  19. Differential expression proteomics to investigate responses and resistance to Orobanche crenata in Medicago truncatula

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    Diego Rubiales

    2009-07-01

    Full Text Available Abstract Background Parasitic angiosperm Orobanche crenata infection represents a major constraint for the cultivation of legumes worldwide. The level of protection achieved to date is either incomplete or ephemeral. Hence, an efficient control of the parasite requires a better understanding of its interaction and associated resistance mechanisms at molecular levels. Results In order to study the plant response to this parasitic plant and the molecular basis of the resistance we have used a proteomic approach. The root proteome of two accessions of the model legume Medicago truncatula displaying differences in their resistance phenotype, in control as well as in inoculated plants, over two time points (21 and 25 days post infection, has been compared. We report quantitative as well as qualitative differences in the 2-DE maps between early- (SA 27774 and late-resistant (SA 4087 genotypes after Coomassie and silver-staining: 69 differential spots were observed between non-inoculated genotypes, and 42 and 25 spots for SA 4087 and SA 27774 non-inoculated and inoculated plants, respectively. In all, 49 differential spots were identified by peptide mass fingerprinting (PMF following MALDI-TOF/TOF mass spectrometry. Many of the proteins showing significant differences between genotypes and after parasitic infection belong to the functional category of defense and stress-related proteins. A number of spots correspond to proteins with the same function, and might represent members of a multigenic family or post-transcriptional forms of the same protein. Conclusion The results obtained suggest the existence of a generic defense mechanism operating during the early stages of infection and differing in both genotypes. The faster response to the infection observed in the SA 27774 genotype might be due to the action of proteins targeted against key elements needed for the parasite's successful infection, such as protease inhibitors. Our data are discussed and

  20. Differential expression proteomics to investigate responses and resistance to Orobanche crenata in Medicago truncatula.

    Science.gov (United States)

    Castillejo, Ma Angeles; Maldonado, Ana M; Dumas-Gaudot, Eliane; Fernández-Aparicio, Mónica; Susín, Rafael; Diego, Rubiales; Jorrín, Jesús V

    2009-07-03

    Parasitic angiosperm Orobanche crenata infection represents a major constraint for the cultivation of legumes worldwide. The level of protection achieved to date is either incomplete or ephemeral. Hence, an efficient control of the parasite requires a better understanding of its interaction and associated resistance mechanisms at molecular levels. In order to study the plant response to this parasitic plant and the molecular basis of the resistance we have used a proteomic approach. The root proteome of two accessions of the model legume Medicago truncatula displaying differences in their resistance phenotype, in control as well as in inoculated plants, over two time points (21 and 25 days post infection), has been compared. We report quantitative as well as qualitative differences in the 2-DE maps between early- (SA 27774) and late-resistant (SA 4087) genotypes after Coomassie and silver-staining: 69 differential spots were observed between non-inoculated genotypes, and 42 and 25 spots for SA 4087 and SA 27774 non-inoculated and inoculated plants, respectively. In all, 49 differential spots were identified by peptide mass fingerprinting (PMF) following MALDI-TOF/TOF mass spectrometry. Many of the proteins showing significant differences between genotypes and after parasitic infection belong to the functional category of defense and stress-related proteins. A number of spots correspond to proteins with the same function, and might represent members of a multigenic family or post-transcriptional forms of the same protein. The results obtained suggest the existence of a generic defense mechanism operating during the early stages of infection and differing in both genotypes. The faster response to the infection observed in the SA 27774 genotype might be due to the action of proteins targeted against key elements needed for the parasite's successful infection, such as protease inhibitors. Our data are discussed and compared with those previously obtained with pea 1 and

  1. Characterization resistance mechanisms in faba bean (Vicia faba against broomrape species (Orobanche and Phelipanche spp.

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    Diego Rubiales

    2016-11-01

    Full Text Available Faba bean (Vicia faba production in Mediterranean and Near East agriculture is severely constrained by broomrape infection. The most widely distributed broomrape species affecting faba bean is Orobanche crenata, although O. foetida and Phelipanche aegyptiaca are of local importance. Only moderately resistant cultivars are available to farmers. Rizotrons studies allowed the dissection of resistance components in faba bean accessions against the very infective species O. crenata, O. foetida var. broteri and P. aegyptiaca, and to the inappropriate P. ramosa and O. foetida var. foetida. Results confirm that some levels of incomplete resistance are available, resulting in a reduced number of broomrape tubercles successfully formed per faba bean plant. Interestingly, the intermediate levels of resistance of cv. Baraca were operative against all broomrape populations and species studied, confirming previous reports on the stability of resistance of Baraca in field trials in different countries. Low induction of seed germination played a major role in the resistance against the inappropriate O. foetida var. foetida but not against the also inappropriate P. ramosa, neither to the infective species O. crenata, O. foetida var. broteri or P. aegyptiaca. Negative tropism of germinated seeds with radicles growing away from faba bean roots was marked for both inappropriate species but was not observed in any of the infective species. Also, a proportion of radicles that had successfully contacted faba bean roots became necrotic, failing in starting tubercle development, particularly frequent for the two inappropriate species. Such necrosis was significant also on radicles contacting resistant faba bean accessions, being particularly relevant for Spanish O. crenata population, and lower although still significant in some accessions against Syrian O. crenata and P. aegytiaca, suggesting that this might also be an operative mechanism to be selected and further

  2. N-Phthaloylglycine-derived strigol analogues. Influence of the D-ring on the seed germination activity of the parasitic weeds Striga hermonthica and Orobanche crenata

    NARCIS (Netherlands)

    Thuring, J.W.J.F.; Bitter, J.H.; Kok, M.M.K. de; Nefkens, G.H.L.; Riel, A.M.D.A. van; Zwanenburg, B.

    1997-01-01

    Several strigol analogues with modifications in the D-ring were synthesized and assayed for germination stimulatory activity of seeds of Striga hermothica and Orobanche crenata. All of these D-ring analogues are derived from N-phthaloylglycine as the common ABC-fragment. It was concluded that the

  3. Characterization of Resistance Mechanisms in Faba Bean (Vicia faba) against Broomrape Species (Orobanche and Phelipanche spp.)

    Science.gov (United States)

    Rubiales, Diego; Rojas-Molina, Maria M.; Sillero, Josefina C.

    2016-01-01

    Faba bean (Vicia faba) production in Mediterranean and Near East agriculture is severely constrained by broomrape infection. The most widely distributed broomrape species affecting faba bean is Orobanche crenata, although O. foetida and Phelipanche aegyptiaca are of local importance. Only moderately resistant cultivars are available to farmers. Rizotrons studies allowed the dissection of resistance components in faba bean accessions against the very infective species O. crenata, O. foetida var. broteri and P. aegyptiaca, and to the inappropriate P. ramosa and O. foetida var. foetida. Results confirm that some levels of incomplete resistance are available, resulting in a reduced number of broomrape tubercles successfully formed per faba bean plant. Interestingly, the intermediate levels of resistance of cv. Baraca were operative against all broomrape populations and species studied, confirming previous reports on the stability of resistance of Baraca in field trials in different countries. Low induction of seed germination played a major role in the resistance against the inappropriate O. foetida var. foetida but not against the also inappropriate P. ramosa, neither to the infective species O. crenata, O. foetida var. broteri, or P. aegyptiaca. Negative tropism of germinated seeds with radicles growing away from faba bean roots was marked for both inappropriate species but was not observed in any of the infective species. Also, a proportion of radicles that had successfully contacted faba bean roots became necrotic, failing in starting tubercle development, particularly frequent for the two inappropriate species. Such necrosis was significant also on radicles contacting resistant faba bean accessions, being particularly relevant for Spanish O. crenata population, and lower although still significant in some accessions against Syrian O. crenata and P. aegyptiaca, suggesting that this might also be an operative mechanism to be selected and further exploited in faba

  4. Characterization of Resistance Mechanisms in Faba Bean (Vicia faba) against Broomrape Species (Orobanche and Phelipanche spp.).

    Science.gov (United States)

    Rubiales, Diego; Rojas-Molina, Maria M; Sillero, Josefina C

    2016-01-01

    Faba bean ( Vicia faba ) production in Mediterranean and Near East agriculture is severely constrained by broomrape infection. The most widely distributed broomrape species affecting faba bean is Orobanche crenata , although O. foetida and Phelipanche aegyptiaca are of local importance. Only moderately resistant cultivars are available to farmers. Rizotrons studies allowed the dissection of resistance components in faba bean accessions against the very infective species O. crenata, O. foetida var. broteri and P. aegyptiaca , and to the inappropriate P. ramosa and O. foetida var. foetida . Results confirm that some levels of incomplete resistance are available, resulting in a reduced number of broomrape tubercles successfully formed per faba bean plant. Interestingly, the intermediate levels of resistance of cv. Baraca were operative against all broomrape populations and species studied, confirming previous reports on the stability of resistance of Baraca in field trials in different countries. Low induction of seed germination played a major role in the resistance against the inappropriate O. foetida var. foetida but not against the also inappropriate P. ramosa , neither to the infective species O. crenata, O. foetida var. broteri , or P. aegyptiaca . Negative tropism of germinated seeds with radicles growing away from faba bean roots was marked for both inappropriate species but was not observed in any of the infective species. Also, a proportion of radicles that had successfully contacted faba bean roots became necrotic, failing in starting tubercle development, particularly frequent for the two inappropriate species. Such necrosis was significant also on radicles contacting resistant faba bean accessions, being particularly relevant for Spanish O. crenata population, and lower although still significant in some accessions against Syrian O. crenata and P. aegyptiaca , suggesting that this might also be an operative mechanism to be selected and further exploited

  5. The effect of Orobanche crenata infection severity in faba bean, field pea, and grass pea productivity.

    Directory of Open Access Journals (Sweden)

    Monica Fernandez-Aparicio

    2016-09-01

    Full Text Available Broomrape weeds (Orobanche and Phelipanche spp. are root holoparasites that feed off a wide range of important crops. Among them, Orobanche crenata attacks legumes complicating their inclusion in cropping systems along the Mediterranean area and West Asia. The detrimental effect of broomrape parasitism in crop yield can reach up to 100% depending on infection severity and the broomrape-crop association. This work provides field data of the consequences of O. crenata infection severity in three legume crops i.e. faba bean, field pea and grass pea. Regression functions modelled productivity losses and revealed trends in dry matter allocation in relation to infection severity. The host species differentially limits parasitic sink strength indicating different levels of broomrape tolerance at equivalent infection severities. Reductions in host aboveground biomass were observed starting at low infection severity and half maximal inhibitory performance was predicted as 4.5, 8.2 and 1.5 parasites per faba bean, field pea and grass pea plant, respectively. Reductions in host biomass occurred in both vegetative and reproductive organs, the latter resulting more affected. The proportion of resources allocated within the parasite was concomitant to reduction of host seed yield indicating that parasite growth and host reproduction compete directly for resources within a host plant. However, the parasitic sink activity does not fully explain the total host biomass reduction because combined biomass of host-parasite complex was lower than the biomass of uninfected plants. In grass pea, the seed yield was negligible at severities higher than 4 parasites per plant. In contrast, faba bean and field pea sustained low but significant seed production at the highest infection severity. Data on seed yield and seed number indicated that the sensitivity of field pea to O. crenata limited the production of grain yield by reducing seed number but maintaining seed size

  6. The Effect of Orobanche crenata Infection Severity in Faba Bean, Field Pea, and Grass Pea Productivity.

    Science.gov (United States)

    Fernández-Aparicio, Mónica; Flores, Fernando; Rubiales, Diego

    2016-01-01

    Broomrape weeds ( Orobanche and Phelipanche spp.) are root holoparasites that feed off a wide range of important crops. Among them, Orobanche crenata attacks legumes complicating their inclusion in cropping systems along the Mediterranean area and West Asia. The detrimental effect of broomrape parasitism in crop yield can reach up to 100% depending on infection severity and the broomrape-crop association. This work provides field data of the consequences of O. crenata infection severity in three legume crops, i.e., faba bean, field pea, and grass pea. Regression functions modeled productivity losses and revealed trends in dry matter allocation in relation to infection severity. The host species differentially limits parasitic sink strength indicating different levels of broomrape tolerance at equivalent infection severities. Reductions in host aboveground biomass were observed starting at low infection severity and half maximal inhibitory performance was predicted as 4.5, 8.2, and 1.5 parasites per faba bean, field pea, and grass pea plant, respectively. Reductions in host biomass occurred in both vegetative and reproductive organs, the latter resulting more affected. The increase of resources allocated within the parasite was concomitant to reduction of host seed yield indicating that parasite growth and host reproduction compete directly for resources within a host plant. However, the parasitic sink activity does not fully explain the total host biomass reduction because combined biomass of host-parasite complex was lower than the biomass of uninfected plants. In grass pea, the seed yield was negligible at severities higher than four parasites per plant. In contrast, faba bean and field pea sustained low but significant seed production at the highest infection severity. Data on seed yield and seed number indicated that the sensitivity of field pea to O. crenata limited the production of grain yield by reducing seed number but maintaining seed size. In contrast

  7. Proteomic analysis by two-dimensional differential in gel electrophoresis (2D DIGE) of the early response of Pisum sativum to Orobanche crenata.

    Science.gov (United States)

    Castillejo, Ma Ángeles; Fernández-Aparicio, Mónica; Rubiales, Diego

    2012-01-01

    Crenate broomrape (Orobanche crenata) is considered to be the major constraint for legume crops in Mediterranean countries. Strategies of control have been developed, but only marginal successes have been achieved. For the efficient control of the parasite, a better understanding of its interaction and associated resistance mechanisms at the molecular level is required. The pea response to this parasitic plant and the molecular basis of the resistance was studied using a proteomic approach based on 2D DIGE and MALDI-MSMS analysis. For this purpose, two genotypes showing different levels of resistance to O. crenata, as well as three time points (21, 25, and 30 d after inoculation) have been compared. Multivariate statistical analysis identified 43 differential protein spots under the experimental conditions (genotypes/treatments), 22 of which were identified using a combination of peptide mass fingerprinting (PMF) and MSMS fragmentation. Most of the proteins identified were metabolic and stress-related proteins and a high percentage of them (86%) matched with specific proteins of legume species. The behaviour pattern of the identified proteins suggests the existence of defence mechanisms operating during the early stages of infection that differed in both genotypes. Among these, several proteins were identified with protease activity which could play an important role in preventing the penetration and connection to the vascular system of the parasite. Our data are discussed and compared with those previously obtained in pea and Medicago truncatula.

  8. Genetic relationships among Orobanche species as revealed by RAPD analysis.

    Science.gov (United States)

    Román, B; Alfaro, C; Torres, A M; Moreno, M T; Satovic, Z; Pujadas, A; Rubiales, D

    2003-05-01

    RAPD markers were used to study variation among 20 taxa in the genus OROBANCHE: O. alba, O. amethystea, O. arenaria, O. ballotae, O. cernua, O. clausonis, O. cumana, O. crenata, O. densiflora, O. foetida, O. foetida var. broteri, O. gracilis, O. haenseleri, O. hederae, O. latisquama, O. mutelii, O. nana, O. ramosa, O. rapum-genistae and O. santolinae. A total of 202 amplification products generated with five arbitrary RAPD primers was obtained and species-specific markers were identified. The estimated Jaccard's differences between the species varied between 0 and 0.864. The pattern of interspecific variation obtained is in general agreement with previous taxonomic studies based on morphology, and the partition into two different sections (Trionychon and Orobanche) is generally clear. However, the position in the dendrogram of O. clausonis did not fit this classification since it clustered with members of section TRIONYCHON: Within this section, O. arenaria was relatively isolated from the other members of the section: O. mutelii, O. nana and O. ramosa. Within section Orobanche, all O. ramosa populations showed a similar amplification pattern, whereas differences among O. crenata populations growing on different hosts were found. Orobanche foetida and O. densiflora clustered together, supporting the morphological and cytological similarities and the host preferences of these species.

  9. Low strigolactone root exudation: a novel mechanism of broomrape (Orobanche and Phelipanche spp.) resistance available for faba bean breeding.

    Science.gov (United States)

    Fernández-Aparicio, Mónica; Kisugi, Takaya; Xie, Xiaonan; Rubiales, Diego; Yoneyama, Koichi

    2014-07-23

    Faba bean yield is severely constrained in the Mediterranean region and Middle East by the parasitic weeds Orobanche crenata, O. foetida, and Phelipanche aegyptiaca. Seed germination of these weeds is triggered upon recognition of host root exudates. Only recently faba bean accessions have been identified with resistance based in low induction of parasitic seed germination, but the underlying mechanism was not identified. Strigolactones are a group of terpenoid lactones involved in the host recognition by parasitic plants. Our LC-MS/MS analysis of root exudates of the susceptible accession Prothabon detected orobanchol, orobanchyl acetate, and a novel germination stimulant. A time course analysis indicated that their concentration increased with plant age. However, low or undetectable amounts of these germination stimulants were detected in root exudates of the resistant lines Quijote and Navio at all plant ages. A time course analysis of seed germination induced by root exudates of each faba bean accession indicated important differences in the ability to stimulate parasitic germination. Results presented here show that resistance to parasitic weeds based on low strigolactone exudation does exist within faba bean germplasm. Therefore, selection for this trait is feasible in a breeding program. The remarkable fact that low induction of germination is similarly operative against O. crenata, O. foetida, and P. aegyptiaca reinforces the value of this resistance.

  10. A proteomic approach to studying plant response to crenate broomrape (Orobanche crenata) in pea (Pisum sativum).

    Science.gov (United States)

    Angeles Castillejo, M; Amiour, Nardjis; Dumas-Gaudot, Eliane; Rubiales, Diego; Jorrín, Jesús V

    2004-06-01

    Crenate broomrape (Orobanche crenata) is a parasitic plant that threatens legume production in Mediterranean areas. Pea (Pisum sativum) is severely affected, and only moderate levels of genetic resistance have so far been identified. In the present work we selected the most resistant accession available (Ps 624) and compared it with a susceptible (Messire) cultivar. Experiments were performed by using pot and Petri dish bioassays, showing little differences in the percentage of broomrape seed germination induced by both genotypes, but a significant hamper in the number of successfully installed tubercles and their developmental stage in the Ps 624 compared to Messire. The protein profile of healthy and infected P. sativum root tissue were analysed by two-dimensional electrophoresis. Approximately 500 individual protein spots could be detected on silver stained gels. At least 22 different protein spots differentiated control, non-infected, Messire and Ps 624 accessions. Some of them were identified by MALDI-TOF mass spectrometry and database searching as cysteine proteinase, beta-1,3-glucanase, endochitinase, profucosidase, and ABA-responsive protein. Both qualitative and quantitative differences have been found among infected and non-infected root extracts. Thus, in the infected susceptible Messire genotype 34 spots were decreased, one increased and three newly detected, while in Ps 624, 15 spots were increased, three decreased and one newly detected. In response to the inoculation, proteins that correspond to enzymes of the carbohydrate metabolism (fructokinase, fructose-bisphosphate aldolase), nitrogen metabolism (ferredoxin-NADP reductase) and mitochondrial electronic chain transport (alternative oxidase 2) decreased in the susceptible check, while proteins that correspond to enzymes of the nitrogen assimilation pathway (glutamine synthetase) or typical pathogen defence, PR proteins, including beta-1,3-glucanase and peroxidases, increased in Ps 624. Results are

  11. Sucrose effect on broomrape (Orobanche crenata) development on ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-07-06

    Jul 6, 2009 ... sense, different control means such as ammonium- containing nutrients or essential amino acids ... Afterwards, the plates were wrapped in aluminium foil in order to maintain Orobanche seeds in the dark, .... tion of ammonium sulphate and to increase the yield of faba bean significantly (Kukula and Masri, ...

  12. Induction of Haustorium Development by Sphaeropsidones in Radicles of the Parasitic Weeds Striga and Orobanche. A Structure-Activity Relationship Study.

    Science.gov (United States)

    Fernández-Aparicio, Mónica; Masi, Marco; Maddau, Lucia; Cimmino, Alessio; Evidente, Marco; Rubiales, Diego; Evidente, Antonio

    2016-06-29

    Crop attack by parasitic weeds such as Striga and Orobanche occurs through developmental processes triggered by host chemodetection. Seeds of those weed species remain dormant in the soil until germination is triggered by host root exudates. The development of haustorium, a parasitic plant organ that invades the host to withdraw its nutrients, is also initiated in Orobanchaceae by host molecular cues. The induction of haustorium development by exogenous signals has previously been reported for Striga but not for Orobanche species. In this work, we demonstrate that sphaeropsidone and epi-sphaeropsidone, two phytotoxic cyclohexene oxides isolated from the fungus Diplodia cupressi, a causal agent of cypress canker, induce haustorium development in radicles of the parasitic weeds Striga hermonthica, Orobanche crenata, and Orobanche cumana. This is the first report of chemical stimulation of haustorium development in radicles of Orobanche in the absence of host. In addition, SAR studies were carried out by testing the haustorium-inducing activity of the natural cyclohexene oxides, seven already known and four new hemisynthetic derivatives, in O. cumana, O. crenata, and S. hermonthica, to find a molecular specificity model required for haustorium induction. The results suggested that the haustorium-inducing activity is due to the possibility to convert the natural sphaeropsidone and natural and hemisynthetic derivatives in the corresponding 3-methoxyquinone and that the stereochemistry at C-5 also seems to affect this activity.

  13. Granular formulation of Fusarium oxysporum for biological control of faba bean and tomato Orobanche.

    Science.gov (United States)

    Nemat Alla, Mamdouh M; Shabana, Yasser M; Serag, Mamdouh M; Hassan, Nemat M; El-Hawary, Mohamed M

    2008-12-01

    Orobanche spp. represent a serious threat to a wide range of crops. They are difficult targets for herbicides, and biological control could provide a possible solution. This work therefore aimed to formulate mycoherbicides of Fusarium with adequate shelf life and virulence against Orobanche but safe to faba bean and tomato. Only two isolates of Fusarium oxysporum Schlecht. (Foxy I and Foxy II) obtained from diseased Orobanche shoots were found to be pathogenic to Orobanche crenata Forsk. and Orobanche ramosa L. Conidial suspension of both isolates significantly decreased germination, attachments and tubercles of Orobanche. Microconidia and chlamydospores of both isolates were formulated as mycoherbicides encapsulated in a wheat flour-kaolin matrix (four different formulations). All formulations greatly diminished Orobanche emerged shoots, total shoot number, shoot height, attachment of emerged shoots, the germinated seeds that succeeded in emerging above the soil surface and dry weight. Meanwhile, disease incidence and disease severity of emerged shoots were enhanced. The shelf life was adequate, particularly for coarse, freshly prepared, low-temperature-stored, microconidia-rich formulations. The induced growth reduction of Orobanche-infected host plants seemed to be nullified by formulations, particularly at the highest dose. These formulations seemed to destroy Orobanche but appeared harmless to host plants. Hence, they could be efficiently used as mycoherbicides for biological control of Orobanche in faba bean and tomato.

  14. Fusarium spp. suppress germination and parasitic establishment of bean and hemp broomrapes

    Directory of Open Access Journals (Sweden)

    Mohamed A. Abouzeid

    2010-05-01

    Full Text Available Thirty-nine Fusarium isolates were obtained from newly emerged infected bean broomrape (Orobanche crenata and hemp broomrape (O. ramosa collected from infested fields of faba bean (Vicia faba and tomato (Lycopersicon esculentum respectively, in two governorates located south of Giza, Egypt. All Fusarium isolates were identified to species level and the effect of their culture filtrates on the germination of seeds from the two Orobanche species was tested in vitro. The inhibition of seed germination differed between the tested Fusarium isolates, depending on the plant part from which they were isolated, with isolates from the shoots of Orobanche inhibiting seed germination more than isolates from the inflorescences. The culture filtrates of Fusarium species from O. crenata were more toxic to the seeds of both Orobanche species than the Fusarium filtrates from O. ramosa. Seeds of O. crenata were more resistant to Fusarium culture filtrates than seeds of O. ramosa. The highest inhibition of Orobanche seed germination was achieved by six Fusarium isolates, one of which was identified as F. oxysporum, one as F. equiseti, whilst the other four were all F. compactum. Aqueous mixtures of mycelia and conidia of all the Fusarium isolates were directly sprayed on O. ramosa tubercles attached to the roots of tomato plants grown in transparent plastic bags, and were also used to infest soil in pots seeded with both faba bean and O. crenata. Two of the four F. compactum isolates (22 and 29 were significantly more pathogenic against O. crenata and O. ramosa, respectively, than the other Fusarium isolates tested in the pots and plastic bags. The study clearly shows the potential of biocontrol agents originating in one Orobanche sp. (e.g. O. crenata to control another Orobanche sp. (e.g. O. ramosa, as many Fusarium isolates deriving from O. crenata were found to be more pathogenic to O. ramosa seeds than the isolates from O. ramosa themselves. This may widen the

  15. Broomrape (Orobanche cumana Wallr.) resistance breeding utilizing wild Helianthus species

    Science.gov (United States)

    Wild Helianthus species possess valuable resistance genes for sunflower broomrape (Orobanche cumana Wallr.), especially the 39 largely under-utilized perennial species. Resistance to race F has been transferred into cultivated background via bridging of interspecific amphiploids. More recently, a si...

  16. Economic analysis of sunflower production in the view of orobanche resistance conditions

    International Nuclear Information System (INIS)

    Semerci, A.

    2013-01-01

    The objective of this research is to determine the use of production factors in 3 different types of sunflower production with respect to orobanche resistance in the agricultural enterprises in Thrace Region which is located at European continent of Turkey. The data used in this research have been obtained through questionnaire technique from 571 agricultural enterprises which were determined by Stratified Random Sampling Method in 2009. It has been reached to the highest yield by 189.30 kg da-1 and the highest gross profit by 37.91 US$ da-1 in the production of sunflower, resistant to orobanche. In the research, it has been determined that the rate of soil testing among the sunflower producers is considerably low and almost the whole of the production has been made under rainfed conditions. As a result of the research, it has been concluded that orobanche resistant sunflower, which has higher water productivity than other cultivars by 367.13 g m/sup 3/, will have a higher proportion in the sunflower cultivation areas in future because of its higher contribution to producer welfare. (author)

  17. Ryecyanatines A and B and ryecarbonitrilines A and B, substituted cyanatophenol, cyanatobenzo[1,3]dioxole, and benzo[1,3]dioxolecarbonitriles from rye (Secale cereale L.) root exudates: Novel metabolites with allelopathic activity on Orobanche seed germination and radicle growth.

    Science.gov (United States)

    Cimmino, Alessio; Fernández-Aparicio, Mónica; Avolio, Fabiana; Yoneyama, Koichi; Rubiales, Diego; Evidente, Antonio

    2015-01-01

    Orobanche and Phelipanche species (the broomrapes) are root parasitic plants, some of which represent serious weed problems causing heavy yield losses on important crops. Current control relies on the use of certain agronomic practices, resistant crop varieties, and herbicides, albeit success has been marginal. Agronomic practices such as the use of allelopathic species in intercropping or cover crops, or the use of direct seedling over residues of allelopathic species incorporate the principle of allelopathy exerted by molecules exuded from roots or released by crop residues to control broomrapes. In addition, the isolation of natural substances from root exudates of plants with potential to inhibit broomrape development opens the door to the design of new herbicides based on natural and benign sources. Ryecyanatines A and B and ryecarbonitrilines A and B, the first new substituted cyanatophenol, substituted cyanatobenzo[1,3]dioxole, and the latter two new substituted benzo[1,3]dioxolecarbonitriles were isolated from rye (Secale cereale L.) root exudates. They were characterized as 4-cyanato-2-methoxyphenol, 2-cyanato-benzo[1,3]dioxole, 2-methoxybenzo[1,3]dioxole-5-carbonitrile and benzo[1,3]dioxole-2-carbonitrile by spectroscopic (essentially NMR and HRESI MS spectra) methods. These compounds were investigated for allelopathic activity on Orobanche germination and development. Ryecarbonitriline A induced germination of Orobanche cumana seeds, and this germination can be considered as suicidal because O. cumana does not parasite rye roots and cannot survive without host resources beyond germination stage. In addition, ryecyanatine A promotes a rapid cessation of O. cumana, Orobanche crenata and Orobanche minor radicle growth with the promotion of a layer of papillae at the radicle tip in O. cumana and O. crenata hampering the contact of the parasite to the host. Ryecarbonitriline B also displayed the same activity although being less active than ryecyanatine A and

  18. Diversity and evolution of Ty1-copia and Ty3-gypsy retroelements in the non-photosynthetic flowering plants Orobanche and Phelipanche (Orobanchaceae).

    Science.gov (United States)

    Park, Jeong-Mi; Schneeweiss, Gerald M; Weiss-Schneeweiss, Hanna

    2007-01-31

    We present the first study on the diversity and evolution of Ty1-copia and Ty3-gypsy retroelements in a group of non-photosynthetic flowering plants. To this end partial sequences of the reverse transcriptase (rt) gene were obtained from 20 clones for each retroelement type from seven and six accessions of Orobanche and Phelipanche (Orobanchaceae), respectively. Overall sequence similarity is higher in Ty3-gypsy elements than in Ty1-copia elements in agreement with the results from other angiosperm groups. Higher sequence diversity and stronger phylogenetic structure, especially of Ty1-copia sequences, in Orobanche species compared to Phelipanche species support the previously suggested hypothesis (based on karyological and cytological data) that genomes of Orobanche species are more dynamic than those of Phelipanche species. No evidence was found for intraspecific differences of retroelement diversity nor for differences between pest taxa and their putative wild relatives, e.g., O. crenata and O. owerini. The occurrence of a few sequences from Phelipanche species in clades otherwise comprising sequences from Orobanche species might be due to horizontal gene transfer, but the alternative of vertical transmission cannot be rejected unambiguously.

  19. Recognition of root exudates by seeds of broomrape (Orobanche and Phelipanche) species

    Science.gov (United States)

    Fernández-Aparicio, M.; Flores, F.; Rubiales, D.

    2009-01-01

    Background and Aims The long co-existence of broomrapes and their hosts within the same environment has culminated in a strong adaptation and effective parasitism. As a first step of specialization in the parasitic process, seed receptors of parasitic plant species vary in their ability to recognize compounds released by their hosts. This work aims to investigate potential patterns for the reception requirements needed to activate germination within Orobanche and Phelipanche species. Methods Induction of the germination of seeds of nine Orobanche and Pheliphanche species by root exudates of 41 plant species was studied and subjected to biplot multivariate analysis. Key Results A high level of specialization in root exudate recognition was found in Orobanche densiflora, O. gracilis and O. hederae, which germinated almost exclusively in contact with root exudates from the plants they infect in nature. At the opposite extreme, Phelipanche aegyptiaca, P. ramosa and O. minor were highly generalist, germinating when in contact with the root exudates of most plant species. Orobanche crenata, O. cumana and O. foetida showed intermediate behaviour. Conclusions A universal germination stimulant for all broomrape species has not being identified to date. The synthetic stimulant GR24 is active against most of the weedy broomrape species, but fails with the non-weedy species tested in this study and with the very recent weedy species O. foetida. In addition, germination behaviour of broomrape species depends on the crop plant tested. Weedy broomrapes with a broad host spectrum respond better to the different exudates released by a wide range of crops and wild species than do non-weedy broomrapes, which have a narrow host spectrum and are more restricted to their host range. Root exudates of many plant species were active in stimulating germination of seeds of Orobanche and Phelipanche species for which they are not described as hosts, representing interesting examples of

  20. Taxonomic relationships of some species of orobanche l. evidence from rapd-pcr and issr markers

    International Nuclear Information System (INIS)

    Sharawy, S.; Karakish, E.

    2015-01-01

    The taxonomic relationships among 25 samples representing nine species of Orobanche L. (Orobanchaceae) were determined by the analysis of morphological characters and molecular polymorphism using random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR). In order to construct dendrogram elucidating the relationships among the examined taxa, the coded data were analyzed using the software package NTSYS-pc 2.1 based on the Neighbor-joining (NJ) tree building method based on a distance matrix. The aim of this study is to develop taxonomic relationship based on morphological and molecular data, in order to obtain a more reliable taxonomic relationship of Orobanche species under study. The dendrogram produced by the analysis of the molecular data (RAPD and ISSR) resembled that constructed by NJ dendrogram for the morphological variation. The studied taxa were separated in two groups, the first comprised of the five species of section Trionychon (O. purpurea, O.lavandulacea, O. ramosa, O. mutelii and O. aegyptiaca) and the second comprised of the four species of section Orobanche (O.cernua, O. crenata, O. minor and O. pubescens). High similarity was detected between O. pubescens and O. minor. The results confirmed the close relationship between O. ramosa and O. mutelii. Moreover, this study demonstrated the grouping of the studied taxa in most cases by geographically isolated population. (author)

  1. The strigolactone germination stimulants of the plant-parasitic Striga and Orobanche spp. are derived from the carotenoid pathway.

    Science.gov (United States)

    Matusova, Radoslava; Rani, Kumkum; Verstappen, Francel W A; Franssen, Maurice C R; Beale, Michael H; Bouwmeester, Harro J

    2005-10-01

    The seeds of parasitic plants of the genera Striga and Orobanche will only germinate after induction by a chemical signal exuded from the roots of their host. Up to now, several of these germination stimulants have been isolated and identified in the root exudates of a series of host plants of both Orobanche and Striga spp. In most cases, the compounds were shown to be isoprenoid and belong to one chemical class, collectively called the strigolactones, and suggested by many authors to be sesquiterpene lactones. However, this classification was never proven; hence, the biosynthetic pathways of the germination stimulants are unknown. We have used carotenoid mutants of maize (Zea mays) and inhibitors of isoprenoid pathways on maize, cowpea (Vigna unguiculata), and sorghum (Sorghum bicolor) and assessed the effects on the root exudate-induced germination of Striga hermonthica and Orobanche crenata. Here, we show that for these three host and two parasitic plant species, the strigolactone germination stimulants are derived from the carotenoid pathway. Furthermore, we hypothesize how the germination stimulants are formed. We also discuss this finding as an explanation for some phenomena that have been observed for the host-parasitic plant interaction, such as the effect of mycorrhiza on S. hermonthica infestation.

  2. The Strigolactone Germination Stimulants of the Plant-Parasitic Striga and Orobanche spp. Are Derived from the Carotenoid Pathway1

    Science.gov (United States)

    Matusova, Radoslava; Rani, Kumkum; Verstappen, Francel W.A.; Franssen, Maurice C.R.; Beale, Michael H.; Bouwmeester, Harro J.

    2005-01-01

    The seeds of parasitic plants of the genera Striga and Orobanche will only germinate after induction by a chemical signal exuded from the roots of their host. Up to now, several of these germination stimulants have been isolated and identified in the root exudates of a series of host plants of both Orobanche and Striga spp. In most cases, the compounds were shown to be isoprenoid and belong to one chemical class, collectively called the strigolactones, and suggested by many authors to be sesquiterpene lactones. However, this classification was never proven; hence, the biosynthetic pathways of the germination stimulants are unknown. We have used carotenoid mutants of maize (Zea mays) and inhibitors of isoprenoid pathways on maize, cowpea (Vigna unguiculata), and sorghum (Sorghum bicolor) and assessed the effects on the root exudate-induced germination of Striga hermonthica and Orobanche crenata. Here, we show that for these three host and two parasitic plant species, the strigolactone germination stimulants are derived from the carotenoid pathway. Furthermore, we hypothesize how the germination stimulants are formed. We also discuss this finding as an explanation for some phenomena that have been observed for the host-parasitic plant interaction, such as the effect of mycorrhiza on S. hermonthica infestation. PMID:16183851

  3. Crops with target-site herbicide resistance for Orobanche and Striga control.

    Science.gov (United States)

    Gressel, Jonathan

    2009-05-01

    It is necessary to control root parasitic weeds before or as they attach to the crop. This can only be easily achieved chemically with herbicides that are systemic, or with herbicides that are active in soil. Long-term control can only be attained if the crops do not metabolise the herbicide, i.e. have target-site resistance. Such target-site resistances have allowed foliar applications of herbicides inhibiting enol-pyruvylshikimate phosphate synthase (EPSPS) (glyphosate), acetolactate synthase (ALS) (e.g. chlorsulfuron, imazapyr) and dihydropteroate synthase (asulam) for Orobanche control in experimental conditions with various crops. Large-scale use of imazapyr as a seed dressing of imidazolinone-resistant maize has been commercialised for Striga control. Crops with two target-site resistances will be more resilient to the evolution of resistance in the parasite, if well managed.

  4. Wild sunflower species as a genetic resource for resistance to sunflower broomrape (Orobanche cumana Wallr.)

    Science.gov (United States)

    Broomrape (Orobanche cumana Wallr.) is a parasitic weed that causes economic damage in sunflower production in many countries, especially in Central and Eastern Europe, Spain, Turkey, Israel, Iran, Kazakhstan, and China. Genes for resistance to broomrape races A, B, C, D, and E are present in variet...

  5. Resistance of red clover (Trifolium pratense) to the root parasitic plant Orobanche minor is activated by salicylate but not by jasmonate.

    Science.gov (United States)

    Kusumoto, Dai; Goldwasser, Yaakov; Xie, Xiaonan; Yoneyama, Kaori; Takeuchi, Yasutomo; Yoneyama, Koichi

    2007-09-01

    Obligate root holoparasites of the genus Orobanche attack dicotyledonous crops and cause severe losses in many parts of the world. Chemical induction of plant defence systems such as systemic acquired resistance was proposed to be an available strategy to control the root parasite, but the detailed mechanisms involved have not been clarified. The aim of this study was to elucidate the effects of salicylic acid (SA), jasmonic acid (JA) and their analogues on resistance of red clover to Orobanche parasitism. Roots of red clover grown in plastic chambers were applied with SA, S-methyl benzo[1,2,3]thiadiazole-7-carbothioate (BTH), methyl jasmonate (MeJA) and n-propyl dihydrojasmonate (PDJ), and then were inoculated with O. minor seeds. Attachments of the parasite were observed after 5 weeks. SA and BTH, inducers of SA-mediated defences, significantly reduced the number of established parasites by more than 75 %. By contrast, MeJA and PDJ, inducers of JA-mediated defences, did not affect parasitism. The reduction in the number of established parasites by SA and BTH was due to the inhibited elongation of O. minor radicles and the activation of defence responses in the host root including lignification of the endodermis. These results suggest that SA-induced resistance, but not JA-induced resistance, is effective in inhibiting Orobanche parasitism and that the resistance is expressed by the host root both externally and internally.

  6. Typification de quelques taxons d'orobanches ('Orobanchaceae')

    OpenAIRE

    Jeanmonod, Daniel

    2007-01-01

    Dans le cadre d'une étude sur les Orobanches de Corse, cinq taxons sont lectotypifiés: Orobanche castellana Reut. (= Orobanche amethystea subsp. castellana (Reut.) Rouy), Orobanche rapum var. bracteosa Reut. (= Orobanche rapum-genistae Thuill.), Orobanche rigens f. corsica Beck (= Orobanche rigens Loisel.), Orobanche rigens var. nigricans Beck (= Orobanche rigens Loisel.) et Phelypaea mutelii var. nana Reut. (≡Phelipanche nana (Rchb. f.) Soják). Tous ces lectotypes sont déposés dans les herbi...

  7. Inheritance of resistance to sunflower broomrape (Orobanche cumana Wallr.) in an interspecific cross between Helianthus annuus and Helianthus debilis subsp. tardiflorus

    Science.gov (United States)

    Sunflower broomrape (Orobanche cumana Wallr.) constrains sunflower cultivation in increasing areas of Europe and Asia. Populations classified as race G that overcome all known resistance genes have recently appeared. The objective of this research was to study the inheritance of resistance to broomr...

  8. Antihyperglycaemic potential of the water-ethanol extract of Kalanchoe crenata (Crassulaceae).

    Science.gov (United States)

    Kamgang, René; Mboumi, Rostand Youmbi; Fondjo, Angèle Foyet; Tagne, Michel Archange Fokam; N'dillé, Gabriel Patrice Roland Mengue; Yonkeu, Jeanne Ngogang

    2008-01-01

    Kalanchoe crenata is a vegetable widely used in Cameroon and largely efficient in the treatment of diabetes mellitus. The effect of the water-ethanol extract of this plant (WEKC) on blood glucose levels was investigated in fasting normal and diet-induced diabetic rats (MACAPOS 1) after a short- and medium-term treatment. Diabetes was induced by submitting Wistar rats to a hypercaloric sucrose diet over 4 months. Six hours after a single oral administration of WEKC, 135 and 200 mg kg(-1) body weight extracts significantly (P < 0.01) reduced the blood glucose levels both in normal and diabetic rats without real dose-dependent effect. During the medium-term treatment, 200 mg kg(-1) WEKC administered daily for 4 weeks significantly reduced blood glucose levels within week 1 (P < 0.05), with a maximum effect at week 4 (-52%, P < 0.01), while maintaining glycaemia within the normal range. All the WEKC-treated diabetic rats exhibited significant (P < 0.01) increase in insulin sensitivity index (K (ITT)) compared with the initial time and to the untreated diabetic animals. Animals treated for 4 weeks exhibited a slight resistance in body-weight gain and decrease in food and water intake. The WEKC activities on all parameters assessed were comparable with the glibenclamide effects. Qualitative phytochemical screening revealed that K. crenata contains terpenoids, tannins, polysaccharids, saponins, flavonoids and alkaloids. The data suggest that K. crenata might contain important chemical components that could induce significant improvement in glucose clearance and/or uptake and resistance to body-weight gain and insulin sensitivity, and could be a potent alternative or complementary therapeutic substance in the control of type 2 diabetes and other insulin-resistant conditions.

  9. Strigolactone deficiency confers resistance in tomato line SL-ORT1 to the parasitic weeds Phelipanche and Orobanche spp.

    Science.gov (United States)

    Dor, Evgenia; Yoneyama, Koichi; Wininger, Smadar; Kapulnik, Yoram; Yoneyama, Kaori; Koltai, Hinanit; Xie, Xiaonan; Hershenhorn, Joseph

    2011-02-01

    The parasitic flowering plants of the genera Orobanche and Phelipanche (broomrape species) are obligatory chlorophyll-lacking root-parasitic weeds that infect dicotyledonous plants and cause heavy economic losses in a wide variety of plant species in warm-temperate and subtropical regions. One of the most effective strategies for broomrape control is crop breeding for broomrape resistance. Previous efforts to find natural broomrape-resistant tomato (Solanum lycopersicon) genotypes were unsuccessful, and no broomrape resistance was found in any wild tomato species. Recently, however, the fast-neutron-mutagenized tomato mutant SL-ORT1 was found to be highly resistant to various Phelipanche and Orobanche spp. Nevertheless, SL-ORT1 plants were parasitized by Phelipanche aegyptiaca if grown in pots together with the susceptible tomato cv. M-82. In the present study, no toxic activity or inhibition of Phelipanche seed germination could be detected in the SL-ORT1 root extracts. SL-ORT1 roots did not induce Phelipanche seed germination in pots but they were parasitized, at the same level as M-82, after application of the synthetic germination stimulant GR24 to the rhizosphere. Whereas liquid chromatography coupled to tandem mass spectrometry analysis of root exudates of M-82 revealed the presence of the strigolactones orobanchol, solanacol, and didehydro-orobanchol isomer, these compounds were not found in the exudates of SL-ORT1. It can be concluded that SL-ORT1 resistance results from its inability to produce and secrete natural germination stimulants to the rhizosphere.

  10. Phylogeny of holoparasitic Orobanche (Orobanchaceae) inferred from nuclear ITS sequences.

    Science.gov (United States)

    Schneeweiss, Gerald M; Colwell, Alison; Park, Jeong-Mi; Jang, Chang-Gee; Stuessy, Tod F

    2004-02-01

    Orobanche is the largest genus among the holoparasitic members of Orobanchaceae. We present the first molecular phylogenetic analysis (using nuclear ITS sequences) that includes members of all sections of Orobanche, Gymnocaulis, Myzorrhiza, Trionychon, and Orobanche. Orobanche is not monophyletic, but falls into two lineages: (1) the Orobanche group comprises Orobanche sect. Orobanche and the small Near Asian genus Diphelypaea and is characterized by a chromosome base number of x=19 and (2) the Phelipanche group contains Orobanche sects. Gymnocaulis, Myzorrhiza, and Trionychon and possesses a chromosome base number of x=12. The relationships between these two groups and to other genera such as Boschniakia or Cistanche remain unresolved. Within the Orobanche group, Orobanche macrolepis and Orobanche anatolica (including Orobanche colorata) constitute two phylogenetically distinct lineages. Intrasectional structurings proposed by some authors for O. sect. Orobanche are not confirmed by the molecular data. In most cases, intraspecific sequence divergence between accessions, if present, is negligible and not correlated with morphological or ecological traits. In a few cases, however, there is evidence for the presence of cryptic taxa.

  11. Phylogeny of holoparasitic Orobanche (Orobanchaceae) inferred from nuclear ITS sequences

    Science.gov (United States)

    Schneeweiss, G.M.; Colwell, A.; Park, J.-M.; Jang, C.-G.; Stuessy, Tod F.

    2004-01-01

    Orobanche is the largest genus among the holoparasitic members of Orobanchaceae. We present the first molecular phylogenetic analysis (using nuclear ITS sequences) that includes members of all sections of Orobanche, Gymnocaulis, Myzorrhiza, Trionychon, and Orobanche. Orobanche is not monophyletic, but falls into two lineages: (1) the Orobanche group comprises Orobanche sect. Orobanche and the small Near Asian genus Diphelypaea and is characterized by a chromosome base number of x = 19 and (2) the Phelipanche group contains Orobanche sects. Gymnocaulis, Myzorrhiza, and Trionychon and possesses a chromosome base number of x = 12. The relationships between these two groups and to other genera such as Boschniakia or Cistanche remain unresolved. Within the Orobanche group, Orobanche macrolepis and Orobanche anatolica (including Orobanche colorata) constitute two phylogenetically distinct lineages. Intrasectional structurings proposed by some authors for O. sect. Orobanche are not confirmed by the molecular data. In most cases, intraspecific sequence divergence between accessions, if present, is negligible and not correlated with morphological or ecological traits. In a few cases, however, there is evidence for the presence of cryptic taxa. ?? 2003 Elsevier Science (USA). All rights reserved.

  12. Mapping of quantitative trait loci controlling Orobanche foetida Poir ...

    African Journals Online (AJOL)

    Mapping of quantitative trait loci controlling Orobanche foetida Poir. resistance in faba bean (Vicia faba L.) R Díaz-Ruiz, A Torres, MV Gutierrez, D Rubiales, JI Cubero, M Kharrat, Z Satovic, B Román ...

  13. "Orobanche ballotae" A. Pujadas ("Oronbanchaceae"), especie nueva

    OpenAIRE

    Pujadas Salvá, Antonio J.

    1997-01-01

    Orobanche ballotae A. Pujadas (Orobanchaceae), especie. Se describe para el S de la Península Ibérica una especie nueva del género Orobanche L., de la sección Orobanche, Grex Minores G. Beck. Se destacan sus caracteres morfológicos que permiten diferenciarlo claramente de O. minor Sm., especie con la que presenta ciertas semejanzas.

  14. Is seed conditioning essential for Orobanche germination?

    Science.gov (United States)

    Plakhine, Dina; Ziadna, Hammam; Joel, Daniel M

    2009-05-01

    Parasitic Orobanchaceae germinate only after receiving a chemical stimulus from roots of potential host plants. A preparatory phase of several days that follows seed imbibition, termed conditioning, is known to be required; thereafter the seeds can respond to germination stimulants. The aim of this study was to examine whether conditioning is essential for stimulant receptivity. Non-conditioned seeds of both Orobanche cumana Wallr. and O. aegyptiaca Pers. [syn. Phelipanche aegyptiaca (Pers.) Pomel] were able to germinate in response to chemical stimulation by GR24 even without prior conditioning. Stimulated seeds reached maximal germination rates about 2 weeks after the onset of imbibition, no matter whether the seeds had or had not been conditioned before stimulation. Whereas the lag time between stimulation and germination response of non-conditioned seeds was longer than for conditioned seeds, the total time between imbibition and germination was shorter for the non-conditioned seeds. Unlike the above two species, O. crenata Forsk. was found to require conditioning prior to stimulation. Seeds of O. cumana and O. aegyptiaca are already receptive before conditioning. Thus, conditioning is not involved in stimulant receptivity. A hypothesis is put forward, suggesting that conditioning includes (a) a parasite-specific early phase that allows the imbibed seeds to overcome the stress caused by failing to receive an immediate germination stimulus, and (b) a non-specific later phase that is identical to the pregermination phase between seed imbibition and actual germination that is typical for all higher plants.

  15. Chromosome numbers and karyotype evolution in holoparasitic Orobanche (Orobanchaceae) and related genera

    Science.gov (United States)

    Schneeweiss, G.M.; Palomeque, T.; Colwell, A.E.; Weiss-Schneeweiss, H.

    2004-01-01

    Chromosome numbers and karyotypes of species of Orobanche, Cistanche, and Diphelypaea (Orobanchaceae) were investigated, and 108 chromosome counts of 53 taxa, 19 counted for the first time, are presented with a thorough compilation of previously published data. Additionally, karyotypes of representatives of these genera, including Orobanche sects. Orobanche and Trionychon, are reported. Cistanche (x = 20) has large meta- to submetacentric chromosomes, while those of Diphelypaea (x = 19) are medium-sized submeta-to acrocentrics. Within three analyzed sections of Orobanche, sects. Myzorrhiza (x = 24) and Trionychon (x = 12) possess medium-sized submeta- to acrocentrics, while sect. Orobanche (x = 19) has small, mostly meta- to submetacentric, chromosomes. Polyploidy is unevenly distributed in Orobanche and restricted to a few lineages, e.g., O. sect. Myzorrhiza or Orobanche gracilis and its relatives (sect. Orobanche). The distribution of basic chromosome numbers supports the groups found by molecular phylogenetic analyses: Cistanche has x = 20, the Orobanche-group (Orobanche sect. Orobanche, Diphelypaea) has x = 19, and the Phelipanche-group (Orobanche sects. Gymnocaulis, Myzorrhiza, Trionychon) has x = 12, 24. A model of chromosome number evolution in Orobanche and related genera is presented: from two ancestral base numbers, xh = 5 and xh = 6, independent polyploidizations led to x = 20 (Cistanche) and (after dysploidization) x = 19 (Orobanche-group) and to x = 12 and x = 24 (Phelipanche-group), respectively.

  16. Pre-haustorial resistance to broomrape (Orobanche cumana) in sunflower (Helianthus annuus): cytochemical studies.

    Science.gov (United States)

    Echevarría-Zomeño, Sira; Pérez-de-Luque, Alejandro; Jorrín, Jesús; Maldonado, Ana M

    2006-01-01

    Sunflower broomrape (Orobanche cumana Wallr.) is a root holoparasitic angiosperm considered as one of the major constraints for sunflower production in Mediterranean areas. Breeding for resistance is regarded as the most effective, feasible, and environmentally friendly solution to control this parasite. However, the existing sources of genetic resistance are defeated by the continuous emergence of new more virulent races of the parasite. In this work, the interaction between sunflower and O. cumana has been analysed in order to gain insights into the mechanisms involved in resistance. Two sunflower genotypes were selected showing different behaviour against the new race F of O. cumana, HE-39998 (susceptible) and HE-39999 (resistant), and both compatible and incompatible interactions were compared. Pot and Petri dish bioassays revealed that only HE-39998 plants were severely affected, supporting a high number of successfully established broomrapes to mature flowering, whereas in HE-39999 root tubercles were never observed, resistance being associated with browning symptoms of both parasite and host tissues. Histological aspects of the resistance were further investigated. Suberization and protein cross-linking at the cell wall were seen in the resistant sunflower cells in contact with the parasite, preventing parasite penetration and connection to the host vascular system. In addition, fluorescence and confocal laser microscopy (CLM) observations revealed accumulation of phenolic compounds during the incompatible reaction, which is in agreement with these metabolites playing a defensive role during H. annuus-O. cumana interaction.

  17. PHYTOCHEMICAL ASSESSMENT ON N-HEXANE EXTRACT AND FRACTIONS OF Marsilea crenata Presl. LEAVES THROUGH GC-MS

    Directory of Open Access Journals (Sweden)

    Burhan Ma'arif

    2016-08-01

    Full Text Available Estrogen deficiency causes various health problems in postmenopausal women, including osteoporosis. Phytoestrogen emerged as a potential alternative of estrogen with minimum side effects. Green clover (Marsilea crenata Presl. is a typical plant in East Java which suspected contains estrogen-like substances. The aim of this research was to report the phytochemical properties of M. crenata using GC-MS as a preliminary study. M. crenata leaves were dried and extracted with n-hexane, then separated using vacuum column chromatography to get four fractions, after that the n-hexane extract and four fractions were identified with GC-MS. The results of GC-MS analysis showed some compounds contained in M. crenata leaves like monoterpenoid, diterpenoid, fatty acid compounds, and other unknown compounds. The results obtained in this research indicated a promising potential of M. crenata as medicinal plants, especially as antiosteoporotic agent.

  18. History of the race structure of Orobanche cumana and the breeding of sunflower for resistance to this parasitic weed: A review

    Energy Technology Data Exchange (ETDEWEB)

    Molinero-Ruiz, L.; Delavault, P.; Pérez-Vich, B.; Pacureanu-Joita, M.; Bulos, M.; Altieri, E.; Domínguez, J.

    2015-07-01

    Broomrape, caused by Orobanche cumana, has affected sunflowers since the early 20th century in Eastern Europe. Currently, it limits sunflower oil production in Southern and Eastern Europe and in some areas of Asia, causing around 50% seed losses when susceptible hybrids are grown. Covered in this review are aspects such as: biological processes that are common to Orobanche spp. and/or particular to O. cumana in sunflower, genetic resistance and its mechanisms, races of the parasite identified in different countries throughout the time and their increasing virulence, and breeding for resistance to some herbicides as a novel control option. The main purpose is to present an updated and, as far as possible, complete picture of the way both the parasitic weed and its host crop have evolved in time, and how they co-exist in the current agriculture. Additionally, we propose a system for determining the races of the parasite that can be internationally adopted from now. In the context of minimal harmful effects on the environment, changing patterns of land use in farming systems, and global environment changes, the final goal of this work is to provide all those interested in parasites from field crops and their integrated management compiled information on the sunflower – O. cumana system as a case study. (Author)

  19. First report of Orobanche ludoviciana parasitizing sunflowers

    Science.gov (United States)

    Broomrape is the common name given to a group of flowering plants belonging to the genus Orobanche that parasitize the roots of higher dicotyledonous plants. More than 100 species of Orobanche have been identified, all of which are obligate parasites that lack chlorophyll and depend upon their host ...

  20. Candidate gene analysis and identification of TRAP and SSR markers linked to the Or5 gene, which confers sunflower resistance to race E of broomrape (Orobanche cumana Wallr.)

    Science.gov (United States)

    Sunflower broomrape (Orobanche cumana Wallr.) is a root holoparasitic angiosperm considered as being one of the major constraints for sunflower production in Mediterranean areas. Breeding for resistance has been crucial for protecting sunflowers from broomrape damage. The Or5 gene, which confers re...

  1. Phenylpropanoid glycosides in Italian Orobanche spp., sect. Orobanche.

    Science.gov (United States)

    Serafini, M; Corazzi, G; Poli, F; Piccin, A; Tomassini, L; Foddai, S

    2005-09-01

    We studied the occurrence of phenylpropanoid glycosides (PhG) in five species of the genus Orobanche L., collected in the Latium region of Italy. The presence of orobanchoside and verbascoside in all four species confirms that these PhGs are taxonomic markers of the genus. The results suggest that O. gracilis form. citrina could be a diverse entity.

  2. Quantitative trait loci for broomrape (Orobanche cumana Wallr.) resistance in sunflower.

    Science.gov (United States)

    Pérez-Vich, B; Akhtouch, B; Knapp, S J; Leon, A J; Velasco, L; Fernández-Martínez, J M; Berry, S T

    2004-06-01

    Broomrape (Orobanche cumana Wallr.) is a root parasite of sunflower that is regarded as one of the most important constraints of sunflower production in the Mediterranean region. Breeding for resistance is the most effective method of control. P-96 is a sunflower line which shows dominant resistance to broomrape race E and recessive resistance to the very new race F. The objective of this study was to map and characterize quantitative trait loci (QTL) for resistance to race E and to race F of broomrape in P-96. A population from a cross between P-96 and the susceptible line P-21 was phenotyped for broomrape resistance in four experiments, two for race E and two for race F, by measuring different resistance parameters (resistance or susceptibility, number of broomrape per plant, and proportion of resistant plants per F(3) family). This population was also genotyped with microsatellite and RFLP markers. A linkage map comprising 103 marker loci distributed on 17 linkage groups was developed, and composite interval mapping analyses were performed. In total, five QTL ( or1.1, or3.1, or7.1 or13.1 and or13.2) for resistance to race E and six QTL ( or1.1, or4.1, or5.1, or13.1, or13.2 and or16.1) for resistance to race F of broomrape were detected on 7 of the 17 linkage groups. Phenotypic variance for race E resistance was mainly explained by the major QTL or3.1 associated to the resistance or susceptibility character ( R(2)=59%), while race F resistance was explained by QTL with a small to moderate effect ( R(2) from 15.0% to 38.7%), mainly associated with the number of broomrape per plant. Or3.1 was race E-specific, while or1.1, or13.1 and or13.2 of were non-race specific. Or13.1, and or13.2 were stable across the four experiments. Or3.1, and or7.1 were stable over the two race E experiments and or1.1 and or5.1 over the two race F experiments. The results from this study suggest that resistance to broomrape in sunflower is controlled by a combination of qualitative, race

  3. History of the race structure of Orobanche cumana and the breeding of sunflower for resistance to this parasitic weed: A review

    Directory of Open Access Journals (Sweden)

    Leire Molinero-Ruiz

    2015-12-01

    Full Text Available Broomrape, caused by Orobanche cumana, has affected sunflowers since the early 20th century in Eastern Europe. Currently, it limits sunflower oil production in Southern and Eastern Europe and in some areas of Asia, causing around 50% seed losses when susceptible hybrids are grown. Covered in this review are aspects such as: biological processes that are common to Orobanche spp. and/or particular to O. cumana in sunflower, genetic resistance and its mechanisms, races of the parasite identified in different countries throughout the time and their increasing virulence, and breeding for resistance to some herbicides as a novel control option. The main purpose is to present an updated and, as far as possible, complete picture of the way both the parasitic weed and its host crop have evolved in time, and how they co-exist in the current agriculture. Additionally, we propose a system for determining the races of the parasite that can be internationally adopted from now. In the context of minimal harmful effects on the environment, changing patterns of land use in farming systems, and global environment changes, the final goal of this work is to provide all those interested in parasites from field crops and their integrated management compiled information on the sunflower – O. cumana system as a case study.

  4. IAA production during germination of Orobanche spp. seeds.

    Science.gov (United States)

    Slavov, Slavtcho; van Onckelen, Henry; Batchvarova, Rossitza; Atanassov, Atanas; Prinsen, Els

    2004-07-01

    Broomrapes (Orobanche spp.) are parasitic plants, whose growth and development fully depend on the nutritional connection established between the parasite and the roots of the respective host plant. Phytohormones are known to play a role in establishing the specific Orobanche-host plant interaction. The first step in the interaction is seed germination triggered by a germination stimulant secreted by the host-plant roots. We quantified indole-3-acetic acid (IAA) and abscisic acid (ABA) during the seed germination of tobacco broomrape (Orobanche ramosa) and sunflower broomrape (O. cumana). IAA was mainly released from Orobanche seeds in host-parasite interactions as compared to non-host-parasite interactions. Moreover, germinating seeds of O. ramosa released IAA as early as 24 h after the seeds were exposed to the germination stimulant, even before development of the germ tube. ABA levels remained unchanged during the germination of the parasites' seeds. The results presented here show that IAA production is probably part of a mechanism triggering germination upon the induction by the host factor, thus resulting in seed germination.

  5. Effect of imazapyr treated maize on Striga infestation and time of ...

    African Journals Online (AJOL)

    User

    2015-01-21

    Jan 21, 2015 ... Falconer, D. S. (1989) Introduction to quantitative genetics, 3rd edition. Longman Scientific and. Technical Essex England. Garcia-Torres, L. and Lopez-Granados, F. (1991). Control of bromerape (Orobanche crenata. Forsk.) in broad bean (Vicia faba L.) with imadazolines and other herbicides. Weed. Res.

  6. Phenotypical and biochemical characterisation of resistance for parasitic weed (Orobanche foetida Poir.) in radiation-mutagenised mutants of chickpea.

    Science.gov (United States)

    Brahmi, Ines; Mabrouk, Yassine; Brun, Guillaume; Delavault, Philippe; Belhadj, Omrane; Simier, Philippe

    2016-12-01

    Some radiation-mutagenised chickpea mutants potentially resistant to the broomrape, Orobanche foetida Poir., were selected through field trials. The objectives of this work were to confirm resistance under artificial infestation, in pots and mini-rhizotron systems, and to determine the developmental stages of broomrape affected by resistance and the relevant resistance mechanisms induced by radiation mutagenesis. Among 30 mutants tested for resistance to O. foetida, five shared strong resistance in both pot experiments and mini-rhizotron systems. Resistance was not complete, but the few individuals that escaped resistance displayed high disorders of shoot development. Results demonstrated a 2-3-fold decrease in stimulatory activity of root exudates towards broomrape seed germination in resistant mutants in comparison with non-irradiated control plants and susceptible mutants. Resistance was associated with an induction of broomrape necrosis early during infection. When infested, most of the resistant mutants shared enhanced levels of soluble phenolic contents, phenylalanine ammonia lyase activity, guaiacol peroxidase activity and polyphenol oxidase activity, in addition to glutathione and notably ascorbate peroxidase gene expression in roots. Results confirmed enhanced resistance in chickpea radiation-mutagenised mutants, and demonstrated that resistance is based on alteration of root exudation, presumed cell-wall reinforcement and change in root oxidative status in response to infection. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  7. iTRAQ-based proteomics of sunflower cultivars differing in resistance to parasitic weed Orobanche cumana.

    Science.gov (United States)

    Yang, Chong; Xu, Ling; Zhang, Na; Islam, Faisal; Song, Wenjian; Hu, Luyang; Liu, Dan; Xie, Xiaonan; Zhou, Weijun

    2017-07-01

    Orobanche cumana is an obligate root parasite causing severe damage to many economically important crops, including sunflowers worldwide. For efficient control measures, it is necessary to understand the resistant mechanism during interaction at molecular level. The present study emphasizes on comparative proteomics to investigate the mechanistic basis of compatible and incompatible interaction of O. cumana with resistant (JY207) and susceptible (TK0409) sunflowers. More than 3500 proteins were identified from two cultivars by iTRAQ analysis. Identified proteins associated with general functions, posttranslational modification, energy production and conversion, carbohydrate transport and metabolism, and signal transduction mechanisms were the most represented category of induced proteins in both cultivars. The resistant interaction was characterized by alteration of defense-related proteins involved in recognition of parasites, accumulation of pathogenesis-related proteins, biosynthesis of lignin, and detoxification of toxic metabolites in JY207 after inoculation. The susceptible interaction was characterized by decreased abundance of proteins involved in biosynthesis and signaling of plant growth regulators including auxin, gibberellin, brassinosteroid, and ethylene in TK0409 after inoculation. The present study provides comprehensive details of proteins and differential modulation of pathways regulated under compatible and incompatible interaction, allowing the identification of important molecular components for development of sustainable resistance against this parasite. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Sunflower Resistance to Broomrape (Orobanche cumana) Is Controlled by Specific QTLs for Different Parasitism Stages.

    Science.gov (United States)

    Louarn, Johann; Boniface, Marie-Claude; Pouilly, Nicolas; Velasco, Leonardo; Pérez-Vich, Begoña; Vincourt, Patrick; Muños, Stéphane

    2016-01-01

    Orobanche cumana (sunflower broomrape) is an obligatory and non-photosynthetic root parasitic plant that specifically infects the sunflower. It is located in Europe and in Asia, where it can cause yield losses of over 80%. More aggressive races have evolved, mainly around the Black Sea, and broomrape can rapidly spread to new areas. Breeding for resistance seems to be the most efficient and sustainable approach to control broomrape infestation. In our study, we used a population of 101 recombinant inbred lines (RILs), derived from a cross between the two lines HA89 and LR1 (a line derived from an interspecific cross with Helianthus debilis). Rhizotrons, pots and field experiments were used to characterize all RILs for their resistance to O. cumana race F parasitism at three post vascular connection life stages: (i) early attachment of the parasite to the sunflower roots, (ii) young tubercle and (iii) shoot emergence. In addition, RIL resistance to race G at young tubercle development stage was evaluated in pots. The entire population was genotyped, and QTLs were mapped. Different QTLs were identified for each race (F from Spain and G from Turkey) and for the three stages of broomrape development. The results indicate that there are several quantitative resistance mechanisms controlling the infection by O. cumana that can be used in sunflower breeding.

  9. Sunflower resistance to broomrape (Orobanche cumana is controlled by specific QTLs for different parasitism stages

    Directory of Open Access Journals (Sweden)

    Johann eLouarn

    2016-05-01

    Full Text Available Orobanche cumana (sunflower broomrape is an obligatory and non-photosynthetic root parasitic plant that specifically infects the sunflower. It is located in Europe and in Asia, where it can cause yield losses of over 80%. More aggressive races have evolved, mainly around the Black Sea, and broomrape can rapidly spread to new areas. Breeding for resistance seems to be the most efficient and sustainable approach to control broomrape infestation.In our study, we used a population of 101 recombinant inbred lines (RILs, derived from a cross between the two lines HA89 and LR1 (a line derived from an interspecific cross with H. debilis. Rhizotrons, pots and field experiments were used to characterize all RILs for their resistance to O. cumana race F parasitism at three post vascular connection life stages: (i early attachment of the parasite to the sunflower roots, (ii young tubercle and (iii shoot emergence. In addition, RIL resistance to race G at young tubercle development stage was evaluated in pots. The entire population was genotyped, and QTLs were mapped. Different QTLs were identified for each race (F from Spain and G from Turkey and for the three stages of broomrape development.The results indicate that there are several quantitative resistance mechanisms controlling the infection by O. cumana that can be used in sunflower breeding.

  10. Sunflower Resistance to Broomrape (Orobanche cumana) Is Controlled by Specific QTLs for Different Parasitism Stages

    Science.gov (United States)

    Louarn, Johann; Boniface, Marie-Claude; Pouilly, Nicolas; Velasco, Leonardo; Pérez-Vich, Begoña; Vincourt, Patrick; Muños, Stéphane

    2016-01-01

    Orobanche cumana (sunflower broomrape) is an obligatory and non-photosynthetic root parasitic plant that specifically infects the sunflower. It is located in Europe and in Asia, where it can cause yield losses of over 80%. More aggressive races have evolved, mainly around the Black Sea, and broomrape can rapidly spread to new areas. Breeding for resistance seems to be the most efficient and sustainable approach to control broomrape infestation. In our study, we used a population of 101 recombinant inbred lines (RILs), derived from a cross between the two lines HA89 and LR1 (a line derived from an interspecific cross with Helianthus debilis). Rhizotrons, pots and field experiments were used to characterize all RILs for their resistance to O. cumana race F parasitism at three post vascular connection life stages: (i) early attachment of the parasite to the sunflower roots, (ii) young tubercle and (iii) shoot emergence. In addition, RIL resistance to race G at young tubercle development stage was evaluated in pots. The entire population was genotyped, and QTLs were mapped. Different QTLs were identified for each race (F from Spain and G from Turkey) and for the three stages of broomrape development. The results indicate that there are several quantitative resistance mechanisms controlling the infection by O. cumana that can be used in sunflower breeding. PMID:27242810

  11. Induction of seed germination in Orobanche spp. by extracts of traditional Chinese medicinal herbs.

    Science.gov (United States)

    Ma, YongQing; Zhang, Wei; Dong, ShuQi; Ren, XiangXiang; An, Yu; Lang, Ming

    2012-03-01

    The co-evolution of Orobanche spp. and their hosts within the same environment has resulted in a high degree of adaptation and effective parasitism whereby the host releases parasite germination stimulants, which are likely to be unstable in the soil. Our objective was to investigate whether extracts from non-host plants, specifically, Chinese medicinal plants, could stimulate germination of Orobanche spp. Samples of 606 Chinese medicinal herb species were extracted with deionized water and methanol. The extracts were used to induce germination of three Orobanche species; Orobanche minor, Orobanche cumana, and Orobanche aegyptiaca. O. minor exhibited a wide range of germination responses to the various herbal extracts. O. cumana and O. aegyptiaca exhibited an intermediate germination response to the herbal extracts. O. minor, which has a narrow host spectrum, showed higher germination rates in response to different herbal extracts compared with those of O. cumana and O. aegyptiaca, which have a broader host spectrum. Methanolic extracts of many Chinese herbal species effectively stimulated seed germination among the Orobanche spp., even though they were not the typical hosts. The effective herbs represent interesting examples of potential trap crops. Different countries can also screen extracts from indigenous herbaceous plants for their ability to induce germination of Orobanche spp. seeds. The use of such species as trap plants could diminish the global soil seed bank of Orobanche.

  12. Next-Generation Sequencing Reveals the Impact of Repetitive DNA Across Phylogenetically Closely Related Genomes of Orobanchaceae

    Science.gov (United States)

    Piednoël, Mathieu; Aberer, Andre J.; Schneeweiss, Gerald M.; Macas, Jiri; Novak, Petr; Gundlach, Heidrun; Temsch, Eva M.; Renner, Susanne S.

    2013-01-01

    We used next-generation sequencing to characterize the genomes of nine species of Orobanchaceae of known phylogenetic relationships, different life forms, and including a polyploid species. The study species are the autotrophic, nonparasitic Lindenbergia philippensis, the hemiparasitic Schwalbea americana, and seven nonphotosynthetic parasitic species of Orobanche (Orobanche crenata, Orobanche cumana, Orobanche gracilis (tetraploid), and Orobanche pancicii) and Phelipanche (Phelipanche lavandulacea, Phelipanche purpurea, and Phelipanche ramosa). Ty3/Gypsy elements comprise 1.93%–28.34% of the nine genomes and Ty1/Copia elements comprise 8.09%–22.83%. When compared with L. philippensis and S. americana, the nonphotosynthetic species contain higher proportions of repetitive DNA sequences, perhaps reflecting relaxed selection on genome size in parasitic organisms. Among the parasitic species, those in the genus Orobanche have smaller genomes but higher proportions of repetitive DNA than those in Phelipanche, mostly due to a diversification of repeats and an accumulation of Ty3/Gypsy elements. Genome downsizing in the tetraploid O. gracilis probably led to sequence loss across most repeat types. PMID:22723303

  13. [Investigation of ethnic medicinal plants Orobanche, Cistanche and Boschniakia].

    Science.gov (United States)

    Bai, Zhen-Fang; Liu, Yong; Wang, Xiao-Qin

    2014-12-01

    In this paper the species of ethnic medicinal plants Orobanche, Cistanche and Boschniakia, and their ethnopharmaceutical uses were comprehensively summarized by field investigation, systematical data analysis and comparison of relevant specimen and references. The results showed that six plants belonging to Orobanche were used as seven kinds of ethnic medicinal plants, two plants attributing Boschniakia were used as ten kinds of ethnic medicinal plants, two plants of Cistanche were used as three ethnic medicinal plants. The same plant was often used as different ethnic medicine in varied ethnic minorities. The effects of the ethnic medicines included yang-tonifying, hemostasis and analgesic activities. Hence, it is necessary to develop the rich plant resource of Orobanche for alleviation of Cistanche resources shortage.

  14. Ha-DEF1, a sunflower defensin, induces cell death in Orobanche parasitic plants.

    Science.gov (United States)

    de Zélicourt, Axel; Letousey, Patricia; Thoiron, Séverine; Campion, Claire; Simoneau, Philippe; Elmorjani, Khalil; Marion, Didier; Simier, Philippe; Delavault, Philippe

    2007-08-01

    Plant defensins are small basic peptides of 5-10 kDa and most of them exhibit antifungal activity. In a sunflower resistant to broomrape, among the three defensin encoding cDNA identified, SF18, SD2 and HaDef1, only HaDef1 presented a preferential root expression pattern and was induced upon infection by the root parasitic plant Orobanche cumana. The amino acid sequence deduced from HaDef1 coding sequence was composed of an endoplasmic reticulum signal sequence of 28 amino acids, a standard defensin domain of 50 amino-acid residues and an unusual C-terminal domain of 30 amino acids with a net positive charge. A 5.8 kDa recombinant mature Ha-DEF1 corresponding to the defensin domain was produced in Escherichia coli and was purified by means of a two-step chromatography procedure, Immobilized Metal Affinity Chromatography (IMAC) and Ion Exchange Chromatography. Investigation of in vitro antifungal activity of Ha-DEF1 showed a strong inhibition on Saccharomyces cerevisiae growth linked to a membrane permeabilization, and a morphogenetic activity on Alternaria brassicicola germ tube development, as already reported for some other plant defensins. Bioassays also revealed that Ha-DEF1 rapidly induced browning symptoms at the radicle apex of Orobanche seedlings but not of another parasitic plant, Striga hermonthica, nor of Arabidopsis thaliana. FDA vital staining showed that these browning areas corresponded to dead cells. These results demonstrate for the first time a lethal effect of defensins on plant cells. The potent mode of action of defensin in Orobanche cell death and the possible involvement in sunflower resistance are discussed.

  15. Phylogeny and intraspecific variability of holoparasitic Orobanche (Orobanchaceae) inferred from plastid rbcL sequences.

    Science.gov (United States)

    Manen, Jean-François; Habashi, Christine; Jeanmonod, Daniel; Park, Jeong-Mi; Schneeweiss, Gerald M

    2004-11-01

    The rbcL sequences of 106 specimens representing 28 species of the four recognized sections of Orobanche were analyzed and compared. Most sequences represent pseudogenes with premature stop codons. This study confirms that the American lineage (sects. Gymnocaulis and Myzorrhiza) contains potentially functional rbcL-copies with intact open reading frames and low rates of non-synonymous substitutions. For the first time, this is also shown for a member of the Eurasian lineage, O. coerulescens of sect. Orobanche, while all other investigated species of sects. Orobanche and Trionychon contain pseudogenes with distorted reading frames and significantly higher rates of non-synonymous substitutions. Phylogenetic analyses of the rbcL sequences give equivocal results concerning the monophyly of Orobanche, and the American lineage might be more closely related to Boschniakia and Cistanche than to the other sections of Orobanche. Additionally, species of sect. Trionychon phylogenetically nest in sect. Orobanche. This is in concordance with results from other plastid markers (rps2 and matK), but in disagreement with other molecular (nuclear ITS), morphological, and karyological data. This might indicate that the ancestor of sect. Trionychon has captured the plastid genome, or parts of it, of a member of sect. Orobanche. Apart from the phylogenetically problematic position of sect. Trionychon, the phylogenetic relationships within sect. Orobanche are similar to those inferred from nuclear ITS data and are close to the traditional groupings traditionally recognized based on morphology. The intraspecific variation of rbcL is low and is neither correlated with intraspecific morphological variability nor with host range. Ancestral character reconstruction using parsimony suggests that the ancestor of O. sect. Orobanche had a narrow host range.

  16. Een Orobanche als graanadventief

    NARCIS (Netherlands)

    Land, van der J.

    1964-01-01

    An Orobanche growing on Matricaria matricarioides (Less.) Porter was collected near a grain warehouse at Rotterdam harbour in 1935. The specimen was originally identified as O. minor Sm., but upon closer examination it appeared to be O. cernua Loefl. This is the first time that a species of this

  17. A plastid gene phylogeny of the non-photosynthetic parasitic Orobanche (Orobanchaceae) and related genera.

    Science.gov (United States)

    Park, Jeong-Mi; Manen, Jean-François; Colwell, Alison E; Schneeweiss, Gerald M

    2008-07-01

    The phylogenetic relationships of the non-photosynthetic Orobanche sensu lato (Orobanchaceae), which includes some of the economically most important parasitic weeds, remain insufficiently understood and controversial. This concerns both the phylogenetic relationships within the genus, in particular its monophyly or lack thereof, and the relationships to other holoparasitic genera such as Cistanche or Conopholis. Here we present the first comprehensive phylogenetic study of this group based on a region from the plastid genome (rps2 gene). Although substitution rates appear to be elevated compared to the photosynthetic members of Orobanchaceae, relationships among the major lineages Cistanche, Conopholis plus Epifagus, Boschniakia rossica (Cham. & Schltdl.) B. Fedtsch., B. himalaica Hook. f. & Thomson, B. hookeri Walp. plus B. strobilacea A. Gray, and Orobanche s. l. remain unresolved. Resolution within Orobanche, however, is much better. In agreement with morphological, cytological and other molecular phylogenetic evidence, five lineages, corresponding to the four traditionally recognised sections (Gymnocaulis, Myzorrhiza, Orobanche, Trionychon) and O. latisquama Reut. ex Boiss. (of sect. Orobanche), can be distinguished. A combined analysis of plastid rps2 and nuclear ITS sequences of the holoparasitic genera results in more resolved and better supported trees, although the relationships among Orobanche s. l., Cistanche, and the clade including the remaining genera is unresolved. Therefore, rps2 is a marker from the plastid genome that is well-suited to be used in combination with other already established nuclear markers for resolving generic relationships of Orobanche and related genera.

  18. Analgesic properties of the aqueous and ethanol extracts of the leaves of Kalanchoe crenata (Crassulaceae).

    Science.gov (United States)

    Nguelefack, T B; Fotio, A L; Watcho, P; Wansi, S L; Dimo, T; Kamanyi, A

    2004-05-01

    The aqueous and ethanol extracts of the dry leaves of Kalanchoe crenata (300 and 600 mg/kg) were evaluated for their analgesic properties on the pain induced by acetic acid, formalin and heat in mice and by pressure on rats. The ethanol extract of K. crenata at a dose of 600 mg/kg produced an inhibition of 61.13% on pain induced by acetic acid and 50.13% for that induced by formalin. An inhibition of 67.18% was observed on pain induced by heat 45 min after the administration of the extract. The aqueous extract administered at a dose of 600 mg/kg produced a maximum effect of 25% on pain induced by pressure. These activities were similar to those produced by a paracetamol-codeine association, while indomethacin exhibited a protective effect only against the writhing test. Our results suggest that the leaves of K. crenata could be a source of analgesic compounds. Copyright 2004 John Wiley & Sons, Ltd.

  19. Orobanche Laxissima Uhlich

    Directory of Open Access Journals (Sweden)

    Piwowarczyk Renata

    2013-12-01

    Full Text Available Orobanche laxissima Uhlich & Rätzel (Orobanchaceae is a probably endemic Caucasian parasite of trees. New localities of this species are reported from the Greater Caucasus: Russia (Dagestan and Azerbaijan. These are the easternmost sites known for the species, so they extend its distribution range. Its hosts, abundance, and habitat preferences at the new localities are described, and a supplemented map of distribution of this species in Caucasus Mts. is provided

  20. A plastid gene phylogeny of the non-photosynthetic parasitic Orobanche (Orobanchaceae) and related genera

    Science.gov (United States)

    Park, J.-M.; Manen, J.-F.; Colwell, A.E.; Schneeweiss, G.M.

    2008-01-01

    The phylogenetic relationships of the non-photosynthetic Orobanche sensu lato (Orobanchaceae), which includes some of the economically most important parasitic weeds, remain insufficiently understood and controversial. This concerns both the phylogenetic relationships within the genus, in particular its monophyly or lack thereof, and the relationships to other holoparasitic genera such as Cistanche or Conopholis. Here we present the first comprehensive phylogenetic study of this group based on a region from the plastid genome (rps2 gene). Although substitution rates appear to be elevated compared to the photosynthetic members of Orobanchaceae, relationships among the major lineages Cistanche, Conopholis plus Epifagus, Boschniakia rossica (Cham. & Schltdl.) B. Fedtsch., B. himalaica Hook. f. & Thomson, B. hookeri Walp. plus B. strobilacea A. Gray, and Orobanche s. l. remain unresolved. Resolution within Orobanche, however, is much better. In agreement with morphological, cytological and other molecular phylogenetic evidence, five lineages, corresponding to the four traditionally recognised sections (Gymnocaulis, Myzorrhiza, Orobanche, Trionychon) and O. latisquama Reut. ex Boiss. (of sect. Orobanche), can be distinguished. A combined analysis of plastid rps2 and nuclear ITS sequences of the holoparasitic genera results in more resolved and better supported trees, although the relationships among Orobanche s. l., Cistanche, and the clade including the remaining genera is unresolved. Therefore, rps2 is a marker from the plastid genome that is well-suited to be used in combination with other already established nuclear markers for resolving generic relationships of Orobanche and related genera. ?? 2008 The Botanical Society of Japan and Springer.

  1. Biological control of Orobanche aegyptiaca by Fusarium oxysporum F. sp. Orobanchein northwest Iran.

    Science.gov (United States)

    Saremi, H; Okhovvat, S M

    2008-01-01

    Broomrape (Orobanche aegyptiaca) is one of the most serious weed pathogen on many plants all over the world, especially in northwest Iran. It causes damage on some plants particularly on tomato, cucumber and other dicotyledonous crops in zanjan province. Broomrape as weed, caused reductions in crop yield, adversely affected crop quality, and resulted in loss of cultivated land due to reduced crop alternatives. Since there were no any chemical methods and other proper technique to control this plant parasite we tried to find a good mechanism for its management in the fields. Our study showed there was a specific species, Fusarium oxysporum f. sp. orobonche that had infected Broomrapes naturally in the field. In point of fact the species was isolated from naturally infected Broomrape in studied Locations. Our surveys showed F. oxysporum f. sp. orobanche caused disease on orobanche spp. in different agricultural fields. Although there were other fungal species which can nearly manage the orobanche but it can be fungal pathogen to other plants. However the best fungal isolate can be F. oxysporum f. sp. orobanche since it may not be pathogen for other plants.

  2. Fusarium infection causes genotoxic disorders and antioxidant-based damages in Orobanche spp.

    Science.gov (United States)

    Aybeke, Mehmet

    2017-08-01

    This study aims to evaluate the toxic effects of Fusarium oxysporum on root parasitic weed, Orobanche spp. Comparative genetic and gene expression studies were conducted on uninfected and fungus-infected orobanches. In genetic studies, isolated total DNA was amplified by RAPD PCR. Fragment properties were analysed by GTS test. According to the results, the fragment properties of control and Fusarium infected (experimental) groups varied widely; and it has been observed that Fusarium has genotoxic effects on the DNA of orobanches. In gene expression studies, the expression levels of genes encoding enzymes or proteins were associated with ROS damage and toxic effects, therefore, gene expressions of Mn-superoxide dismutase (SOD), Zn-superoxide dismutase (=SOD2, mitochondrial), glutamine synthetase (GS), heat shock protein gene (HSP70), BAX, Caspase-3 and BCL2 were significantly higher in the experimental group. In the light of obtained data, it was concluded that F. oxysporum (1) caused heavy ROS damage in Orobanche (2) induced significant irrevocable genotoxic effects on the DNA of Orobanche, (3) degraded protein metabolism and synthesis, and finally (4) triggered apoptosis. The results of this study can be a ground for further research on reducing the toxic effects of Fusarium on agricultural products, so that advancements in bio-herbicide technology may provide a sustainable agricultural production. Copyright © 2017 Elsevier GmbH. All rights reserved.

  3. Comparative anatomy of leaves of Kalanchoe pinnata and K. crenata in sun and shade conditions, as a support for their identification

    Directory of Open Access Journals (Sweden)

    Nattacha S. Moreira

    2012-04-01

    Full Text Available Kalanchoe pinnata (Lam. Pers. and K. crenata (Andrews Haw., Crassulaceae, are popularly used in the treatment of many diseases. Their biological activities, such as anti-leishmaniasis and analgesic, can be useful in phytotherapy. Both species are often misidentified as the other, because of their similar popular uses and names, and the similar external morphology of the leaves. We investigated the existence of anatomical characters that will permit correct identification of the species grown in shade and in sun conditions. We also contribute with new observations on the leaf anatomy of K. pinnata and K. crenata. Fixed (FAA70 leaves were used, and their sections were embedded in Leica historesin. Hydathodes were observed in both species, and for the first time were anatomically described in K. crenata. The species showed anatomical differences in relation to the presence of epidermal idioblasts only in K. crenata, the different pattern of distribution of subepidermal idioblasts, and the presence of leaf buds only in K. pinnata.

  4. Comparative anatomy of leaves of Kalanchoe pinnata and K. crenata in sun and shade conditions, as a support for their identification

    Directory of Open Access Journals (Sweden)

    Nattacha S. Moreira

    2012-10-01

    Full Text Available Kalanchoe pinnata (Lam. Pers. and K. crenata (Andrews Haw., Crassulaceae, are popularly used in the treatment of many diseases. Their biological activities, such as anti-leishmaniasis and analgesic, can be useful in phytotherapy. Both species are often misidentified as the other, because of their similar popular uses and names, and the similar external morphology of the leaves. We investigated the existence of anatomical characters that will permit correct identification of the species grown in shade and in sun conditions. We also contribute with new observations on the leaf anatomy of K. pinnata and K. crenata. Fixed (FAA70 leaves were used, and their sections were embedded in Leica historesin. Hydathodes were observed in both species, and for the first time were anatomically described in K. crenata. The species showed anatomical differences in relation to the presence of epidermal idioblasts only in K. crenata, the different pattern of distribution of subepidermal idioblasts, and the presence of leaf buds only in K. pinnata.

  5. Orobanche rameuse (Orobanche ramosa L. du colza : un risque émergent sous surveillance

    Directory of Open Access Journals (Sweden)

    Gibot-Leclerc Stéphanie

    2006-03-01

    Full Text Available Broomrapes are parasitic plants without chlorophyll, nutritionally depending from their host plant. Orobanche ramosa L. is a parasite of numerous plants including winter oilseed rape. Its presence has been reported for a long time in the South of France. Nevertheless, its presence became a major problem in the Central West region Poitou-Charentes since the middle of the nineties. The phenomenon is under observation, and research work has been undertaken to evaluate its extension risks and to propose efficient solutions. The main extension factors are its ability to produce seeds, its wide ability to germinate in different environmental conditions, its large number of potential host plants, including common weeds present in cropped fields. Short term recommendations intend to favour the host in the nutritional competition and to limit the soil seed bank. For a longer term, several possibilities could be carried out : optimization of false hosts/trap-crops introduction in the rotation which could decrease the soil seed bank ; and breeding for herbicide resistant plants through mutagenesis or genetic transformation.

  6. Fusarium Rot of Orobanche ramosa Parasitizing Tobacco in Southern Italy

    Directory of Open Access Journals (Sweden)

    B. Nanni

    2005-08-01

    Full Text Available In tobacco crops grown in the province of Caserta (southern Italy, we noted, for the first time in Italy, very many broomrape (Orobanche ramosa plants exhibiting mycosis caused by a strain of Fusarium oxysporum that is not pathogenic to tobacco. After a brief description of the symptoms of the disease and its incidence in the field, we discuss, on the basis of the observations made and the data supplied by the literature, the feasibility of using this fungus in programmes to control Orobanche.

  7. Essais préliminaires d'utilisation de Kalanchoe crenata (Crassulacée dans la prophylaxie et le traitement de la coccidiose aviaire

    Directory of Open Access Journals (Sweden)

    Agbédé, G.

    1993-01-01

    Full Text Available Preliminary studies on the utilization of Kalanchoe crenata (Crassulacea in the prophylaxis and treatment of avian coccidiosis. In an experiment aiming at evaluating the efficiency of Kalanchoe crenata (Crassulacea leaves in preventing avian coccidiosis as compared to "Amprolsol" (Amprolium, MSD, 90 "Hybro lourd" breed of broiler chickens were divided into 3 equal groups : A (control, B (treated with infusions of K. crenata leaves, and C (treated with "Amprolsol". Based on the number of oocysts per gram of feces (opg noted until the 7th week of the experiment, it was shown that K. crenata limited oocyst excretion (73.9 % reduction compared to the control treatment, but this occured to a lesser extend than "Amprolsol" (95.7 % reduction compared to the control. In a second experiment designed to compare the effects of the plant in reducing oocyst output to those of the commercial drug, 60 "Hybro lourd" chickens were divided into 2 equal groups D (treated with plant infusions and E (treated with "Amprolsol". The commercial drug reduced the opg by 96.3 % against a 73.4 % reduction for the plant. Given the encouraging results this experiment produced, more advanced studies have to be undertaken to more efficiently use and find the active anticoccidial principles in K. crenata leaves.

  8. Fusarium Infection Causes Phenolic Accumulations and Hormonal Disorders in Orobanche spp.

    Science.gov (United States)

    Aybeke, Mehmet

    2017-12-01

    The physiological effects of Fusarium oxysporum on in-root parasitic weed, Orobanche spp. (broomrape) with references to change in plant hormones and secondary plant constituents were investigated. The levels of IAA, GA, ABA and JA in the experimental group were significantly lower than those in the control group, while the level of SA was higher in the experimental group. In secondary metabolic studies, the quantities of various phenols were measured in the two groups and catechin, syringic acid and p-coumaric acid amounts were significantly higher in the experimental group than in the control group, unlike gallic acid which have a lower amount. Consequently, in the light of all data, it was concluded that Fusarium oxysporum (1) causes heavy hormonal disorder, (2) triggered only SA-mediated defense and (3) induced intensively accumulation of phenolic substances in orobanche. Fusarium oxysporum causes lethal physiological damage on Orobanche spp.

  9. Weed Suppressing Potential and Isolation of Potent Plant Growth Inhibitors from Castanea crenata Sieb. et Zucc

    Directory of Open Access Journals (Sweden)

    Phung Thi Tuyen

    2018-02-01

    Full Text Available This study isolated, determined, and quantified plant growth inhibitors in Japanese chestnut (Castanea crenata Sieb. et Zucc, a deciduous species native to Japan and Korea. In laboratory assays, C. crenata leaves showed strong inhibition on germination and seedling growth of Echinochloa crus-galli (barnyardgrass, Lactuca sativa (lettuce, and Raphanus sativus (radish. Laboratory and greenhouse trials showed that leaves of C. crenata appeared as a promising material to manage weeds, especially the dicot weeds. By GC-MS and HPLC analyses, gallic, protocatechuic, p-hydroxybenzoic, caffeic, ferulic, ellagic, and cinnamic acids were identified and quantified, of which ellagic acid was present in the highest quantity (2.36 mg/g dried leaves. By column chromatography and spectral data (1H- and 13C-NMR, IR, and LC-MS analysis, a compound identified as 2α,3β,7β,23-tetrahydroxyurs-12-ene-28-oic acid (1 was purified from the methanolic leaf extract of C. crenata (0.93 mg/g dried leaves. This constituent showed potent inhibition on growth of E. crus-galli, a problematic weed in agricultural practice. The inhibition of the compound 1 (IC50 = 2.62 and 0.41 mM was >5 fold greater than that of p-hydroxybenzoic acid (IC50 = 15.33 and 2.11 mM on shoot and root growth of E. crus-galli, respectively. Results suggest that the isolated the compound 1 has potential to develop natural herbicides to manage E. crus-galli. This study is the first to isolate and identify 2α,3β,7β,23-tetrahydroxyurs-12-ene-28-oic acid in a plant and report its plant growth inhibitory potential.

  10. Osmoregulation and nutritional relationships between Orobanche foetida and faba bean

    Science.gov (United States)

    Kharrat, Mohamed; Delavault, Philippe; Chaïbi, Wided; Simier, Philippe

    2009-01-01

    The present study aims at comparing the phloem composition of the tolerant XBJ90.03-16-1-1-1 and the susceptible Bachaar genotypes and the impact of the faba bean genotype on the levels of the major solutes and invertase activities in the parasite Orobanche foetida. In comparison to Bachaar, the XBJ90.03-161-1-1 genotype limited the growth of orobanche tubercles under in vitro conditions. The limited growth was due to low soluble invertase activity, low osmotic potential of the infected roots and the organic nitrogen deficiency of the host phloem sap. The faba bean genotype did not affect the osmoregulation process of O. foetida. Among the organic solutes, stachyose, hexoses, starch and free amino acids, mainly asparagine and aspartate were highly accumulated in orobanche. However, asparagine/aspartate, glutamine/glutamate, alanine, serine, gamma amino butyric acid, stachyose, sucrose were identified as the main organic components in the host phloem exudates. The key role of the enzymes α-galactosidase, asparagine synthetase and aspartate oxaloglutarate aminotransferase in the utilization of the host solutes is proposed in O. foetida parasitizing faba bean. PMID:19794856

  11. Aspergillus alliaceus, a new potential biological control of the root parasitic weed Orobanche.

    Science.gov (United States)

    Aybeke, Mehmet; Sen, Burhan; Okten, Suzan

    2014-07-01

    During extensive surveys in fields heavily infested by broomrape in the Trakya Region-Turkey, a different new fungus, Aspergillus alliaceus, was isolated from the infected broomrape. It is aimed to investigate whether or not it is really a pathogen for Orobanche. The fungi was exposed to a greenhouse environment in order to assess its pathogenicity and virulence against Orobanche cernua. In addition, infection tests on Orobanche seeds were also performed under laboratory conditions. The fungus was subjected using two different methods, exposure to a liquid culture with conidial solution and a sclerotial solid culture with fungal mycelia. Cytological studies were carried out at light, TEM and SEM levels. The results show that the sclerotial solid culture with fungal mycelia quickly caused necrosis and was more effective than the other type. It also greatly diminished attachments, tubercles, and caused the emergence of shoots and an increase in the total shoot number of Orobanche. In addition, both when the fungi was exposed to both soil and used to contaminate sunflower seeds, its pathogenicity was more effective. Consequently, it was determined that A. alliaceus was an effective potential biological control of broomrape throughout its life cycle from dormant seed to mature plant. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. The effects of Fusarium oxysporum on broomrape (Orobanche egyptiaca) seed germination.

    Science.gov (United States)

    Hasannejad, S; Zad, S Javad; Alizade, H Mohamad; Rahymian, H

    2006-01-01

    Broomrape (Orobanche aegyptiaca L.), one of the most important parasitic weeds in Iran, is a root parasitic plant that can attack several crops such as tobacco, sunflower, tomato and etc. Several methods were used for Orobanche control, however these methods are inefficient and very costly. Biological control is an additional recent tool for the control of parasitic weeds. In order to study of the fungus Fusarium oxysporum (biocontrol agent) effects on broomrape seed germination, two laboratory studies were conducted in Tehran University. In the first experiment, different concentration of GR60 (0, 1, 2 and 5 ppm) as stimulation factor for Orobanche seeds germination were experimented. Results showed that concentrations of GR60 had a significant effect on seed germination. The highest seed germination percent was obtained in 1 ppm. In the second experiment, the effect of Fusarium oxysporum was tested on O. aegyptiaca seeds germination. The fungus Fusarium oxysporum were isolated from infested and juvenile O. aegyptiaca ower stalks in tomato field in karaj. Fungus spores suspension in different concentrations (0 (Control), 10(5) (T1), 10(6) (T2), 10(7) (T3) and 3 x 10(7) (T4)) from potato dextrose agar (PDA) prepared and together with 1ppm of GR60 concentration were tested on O. aegyptiaca seeds. Results show that the highest inhibition of seed germination obtained in 10(5) spores/ml. With increasing of suspension concentrations, inhibition percent was reduced and mortality of seeds germ tube was increased. In this investigation, Fusarium oxysporum can be used to inhibit seed germination, stimulate the "suicidal germination" of seeds and reduce the Orobanche seed bank.

  13. Maternal tissue is involved in stimulant reception by seeds of the parasitic plant Orobanche.

    Science.gov (United States)

    Plakhine, Dina; Tadmor, Yaakov; Ziadne, Hammam; Joel, Daniel M

    2012-04-01

    A fundamental element in the evolution of obligate root-parasitic angiosperms is their ability to germinate only in response to chemical stimulation by roots, to ensure contact with a nearby nourishing host. The aim of this study was to explore inheritance of the unique germination control in this group of plants. Analysis was made of the segregation of spontaneous (non-induced) germination that appeared in hybrid progenies derived from crosses between Orobanche cernua and O. cumana, which, like all other Orobanche species, are totally dependent on chemical stimulation for the onset of germination, and show negligible spontaneous germination in their natural seed populations. F(1) and F(2) seeds did not germinate in the absence of chemical stimulation, but significant spontaneous germination was found in some F(3) seed families. This indicates that the prevention of non-induced germination in Orobanche seeds, i.e. dependence on an external chemical stimulation for seed germination, is genetically controlled, that this genetic control is expressed in a seed tissue with maternal origin (presumably the perisperm that originates from the nucellus) and that genetic variation for this trait exists in Orobanche species. Similar segregation results were obtained in reciprocal crosses, suggesting that stimulated germination is controlled by nuclear genes.

  14. Orobanche tunetana G. Beck (Orobanchaceae, especie nueva para el continente europeo

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    Pujadas, Antonio

    1997-12-01

    Full Text Available The presence of Orobanche tunetana G. Beck in the south-eastern part of the Iberian Península is noted. An original ilhistrabon, the chorology and the description of the Iberian specimens are given. The differences are also analysed between this species and O. caesia Rchb.. with which it shows certain similarities.Se indica la presencia de Orobanche tunetana G. Beck en el sudeste de la Península Ibérica. Aportamos un icono original, la corología y la descripción de los ejemplares ibéricos. Se analizan las diferencias con O. caesia Rchb., con el que presenta ciertas semejanzas.

  15. Effect of methanolic fraction of Kalanchoe crenata on metabolic parameters in adriamycin-induced renal impairment in rats.

    Science.gov (United States)

    Kamgang, René; Foyet, Angèle F; Essame, Jean-Louis O; Ngogang, Jeanne Y

    2012-01-01

    To investigate the effect of Kalanchoe crenata methanolic fraction (MEKC) on proteinuria, glucosuria, and some other biochemical parameters in adriamycin-induced renal impairment in rats. Ether anesthetized rats received three intravenous injections (days 0, 14, and 28) of 2 mg/kg body weight of adriamycin. Repeated doses of the extract (0, 50, and 68 mg/kg b.w.) and losartan (10 mg/kg b.w.) were administered orally once daily, for 6 weeks, to these rats. Kidney functions were assessed through biochemical parameters. MEKC decreased proteinuria and also the urinary excretion of creatinine, glucose, and urea significantly in diseased rats. A decrease in serum levels of creatinine, urea, potassium, alkaline phosphatase, conjugate bilirubin, and alanine transaminase level was also recorded in nephropathic rats, but plasma levels of uric acid and glucose remained unchanged. Moreover, the plant extract markedly (P < 0.05) increased plasma sodium and decreased (P < 0.01) the urinary sodium and potassium levels. The results indicated that the treatment with the methanolic fraction of K. crenata may improve proteinuria and all other symptoms due to adriamycin-induced nephropathy and, more than losartan, could ameliorate kidney and liver functions. K. crenata could be a potential source of new oral antinephropathic drug.

  16. Growth promotion and protection against Orobanche foetida of ...

    African Journals Online (AJOL)

    Fetid broomrape (Orobanche foetida Poir.) is a chlorophyll lacking holoparasite that subsists on the roots of plants and causes significant damage to the culture of leguminous plants particularly chickpea (Cicer aerietinum L.). The investigation was done about potential of Rhizobium strains for biological control of O. foetida ...

  17. Molecular and karyological data confirm that the enigmatic genus Platypholis from Bonin-Islands (SE Japan) is phylogenetically nested within Orobanche (Orobanchaceae).

    Science.gov (United States)

    Li, Xi; Jang, Tae-Soo; Temsch, Eva M; Kato, Hidetoshi; Takayama, Koji; Schneeweiss, Gerald M

    2017-03-01

    Molecular phylogenetic studies have greatly improved our understanding of phylogenetic relationships of non-photosynthetic parasitic broomrapes (Orobanche and related genera, Orobanchaceae), but a few genera have remained unstudied. One of those is Platypholis, whose sole species, Platypholis boninsimae, is restricted to the Bonin-Islands (Ogasawara Islands) about 1000 km southeast of Japan. Based on overall morphological similarity, Platypholis has been merged with Orobanche, but this hypothesis has never been tested with molecular data. Employing maximum likelihood and Bayesian analyses on a family-wide data set (two plastid markers, matK and rps2, and three nuclear markers, ITS, phyA and phyB) as well as on an ITS data set focusing on Orobanche s. str., it is shown that P. boninsimae Maxim. is phylogenetically closely linked to or even nested within Orobanche s. str. This position is supported both by morphological evidence and by the newly obtained chromosome number of 2n = 38, which is characteristic for the genus Orobanche s. str.

  18. [Study on chemical constituents of Orobanche coerulescens].

    Science.gov (United States)

    Zhao, Jun; Yan, Ming; Huang, Yi; He, Wen-yi; Zhao, Yu

    2007-10-01

    Six compounds were isolated and purified from Orobanche coerulescens by extraction and different kinds of column chromatography. The structures were determined on the basis of spectral analysis. The structures were elucidated as D-mannitol(I), beta-sitosterol(II), succinic acid(III), caffeic acid(IV), protocatechuic aldehyde(V) and daucosterol(VI). All compounds are obtained from this plant for the first time.

  19. Observations on the current status of Orobanche and Striga problems worldwide.

    Science.gov (United States)

    Parker, Chris

    2009-05-01

    Species of Orobanche and Striga are among the most damaging parasitic weed species worldwide, but there are few reliable statistics on the full extent of the economic losses they cause. The distribution, host range and economic importance of the major species of Orobanche and Striga are briefly summarised. A review of literature over the period since 1991 suggests that many million hectares are infested and that the losses amount to $ US billions annually. Unfortunately there are almost no fully reliable figures on which to base these figures precisely. Meanwhile, there is little evidence of any significant change in intensity, range or losses caused over this period. Any reduction in the importance of these damaging weeds is sporadic, and alleviation of the problems is mostly localised. Furthermore, while the importance of Orobanche species may be broadly static, Striga species on cereals continue to become more serious in many countries owing to continued loss of soil fertility. It is suggested that new techniques may be needed for measurement of the extent of losses caused by these genera and their economic impact. There is continued urgency to develop control measures appropriate to the farming systems involved, and to reduce the risk of spread of both groups of parasite to new areas.

  20. Effects of different types and rates of organic manures on Egyptian broomrape (Orobanche aegyptiaca Perss. control in tomato (Lycopersicon esculentum Mill.

    Directory of Open Access Journals (Sweden)

    K. Orooji

    2016-05-01

    Full Text Available In order to study the effect of different types and rates of animal manure and spent mushroom compost on controlling Egyptian broomrape (Orobanche aegyptiaca Perss. in tomato (Mill. Lycopersicon esculentum, two studies were conducted on randomized complete block design with three replications at Research green house, College of Agriculture, Ferdowsi University of Mashhad and Nemooneh field of Astane Ghods Razavi during two years of 2009 and 2010. Greenhouse study treatments were consist of poultry, cow, sheep manure and spent mushroom compost, which each one applied at four rates (10, 20, 30 and 40 t.ha-1. Field experiment treatments were included of poultry, cow and sheep manure that each one applied at two rates (20 and 40 t.ha-1. Result of the greenhouse study indicated that poultry manure significantly reduced orobanch infestation and increase tomato dry weight compared to control. But in the field experiment, the maximum fruit yield (68 t.ha-1 with the minimum orobanch dry weight were obtained with sheep manure. The effect of cow manure was similar to poultry manure in all measured traits. In the field study, rates of manure application had no significant effect on orobanch fresh and dry weights. The findings indicated that all treatments of animal manure reduced orobanch infestation. But the mechanism of orobanch growth suppression due to animal manures application is unknown. It seems fermentation of different organic matters can produced heat and the resulting toxic compounds such as certain organic acids, ammonia and ammonium salts that may reduce orobanch growth at proper concentrations.

  1. What is Orobanche haenseleri var. deludens Beck?

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    Pujadas Salvà, Antonio J.

    2004-12-01

    Full Text Available Orobanche haenseleri var. deludens Beck (Orobanchaceae, a problematic taxon described from Algeciras (Cádiz, S Spain is here identified after studying the original material of Wolley-Dod (BM 4476. It is considered to be the same as O. austrohispanica M.J.Y. Foley and better included, as a variety, under O. gracilis Sm. The new combination O. gracilis var. deludens (Beck A. Pujadas is consequently proposed. It mainly parasites Ulex (Fabaceae in the western Mediterranean Region (Iberian Peninsula and NW Africa.Se identifica Orobanche haenseleri var. deludens Beck (Orobanchaceae, un taxon conflictivo descrito de Algeciras (Cádiz, sur de España, a partir del análisis del material original de Wolley-Dod (BM 4476. Se considera que es lo mismo que O. austrohispanica M.J.Y. Foley, y se incluye en O. gracilis Sm. con rango varietal. Se propone la nueva combinación O. gracilis var. deludens (Beck A. Pujadas. Parasita principalmente a especies del género Ulex (Fabaceae en la Región Mediterránea Occidental (Península Ibérica y noroeste de África.

  2. Differences in crenate broomrape parasitism dynamics on three legume crops using a thermal time model

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    Alejandro Pérez-De-Luque

    2016-12-01

    Full Text Available Root parasitic weeds are a major limiting production factor in a number of crops, and control is difficult. Genetic resistance and chemical control lead the fight, but without unequivocal success. Models that help to describe and even predict the evolution of parasitism underground are a valuable tool for herbicide applications, and even could help in breeding programs. Legumes are heavily affected by Orobanche crenata (crenate broomrape in the Mediterranean basin. This work presents a descriptive model based on thermal time and correlating growing day-degrees (GDD with the different developmental stages of the parasite. The model was developed in three different legume crops (faba bean, grass pea and lentil attacked by crenate broomrape. The developmental stages of the parasite strongly correlated with the GDD and differences were found depending on the host crop.

  3. Effect of gamma ray irradiation on seed germination of Ardisia crenata

    International Nuclear Information System (INIS)

    Huang Donghua; Xu Hong; Huang Yanping; Song Xiaomin

    2011-01-01

    The seeds of Ardisia crenata were used as experimental material and treated with gamma ray under the irradiative doses ranging from 50 to 500 Gy. The results showed that the seed germination rates were not affected under the irradiative dose of 150 Gy and below. The germination potentiality turned to reduce while the irradiative dose was higher than 250 Gy. And in the range of 300 to 500 Gy the germination rates were decreased with the increase of the irradiative dose. (authors)

  4. In Vitro Evaluation of Reversible and Time-Dependent Inhibitory Effects of Kalanchoe crenata on CYP2C19 and CYP3A4 Activities.

    Science.gov (United States)

    Awortwe, Charles; Manda, Vamshi K; Avonto, Cristina; Khan, Shabana I; Khan, Ikhlas A; Walker, Larry A; Bouic, Patrick J; Rosenkranz, Bernd

    2015-01-01

    Kalanchoe crenata popularly known as "dog's liver" is used in most African countries for the treatment of chronic diseases such as diabetes, asthma and HIV/AIDS related infections. The evaluation of K. crenata for herb-drug interactions has not been reported. This study therefore aims to evaluate the risk of K. crenata for herb-drug interaction in vitro. Crude methanol and fractions of K. crenata were incubated and preincubated with recombinant human CYP2C19 and CYP3A4. Comparative studies were conducted in both human liver microsomes and recombinant human CYP to ascertain the inhibition profile of the crude extract and the various fractions. The cocktail approach of recombinant human CYPs was conducted to confirm the inhibition potential of the fractions in the presence of other CYPs. The results showed significant time-dependent inhibition of tested samples on CYP3A4 with crude methanol (39KC), fractions 45A, 45B and 45D given IC50 fold decrease of 3.29, 2.26, 1.91 and 1.49, respective. Time dependent kinetic assessment of 39KC and 45D showed KI and kinact values for 39KC as 1.77 µg/mL and 0.091 min(-1) while that of 45D were 6.45 µg/mL and 0.024 min(-1), respectively. Determination of kinact based on IC50 calculations yielded 0.015 and 0.04 min(-1) for 39KC and 45D, respectively. Cocktail approach exhibited fold decreases in IC50 for all test fractions on CYP3A4 within the ranges of 2.10 - 4.10. At least one phytoconstituent in the crude methanol extract of Kalanchoe crenata is a reversible and time-dependent inhibitor of CYP3A4.

  5. Detection of the parasitic plant, Orobanche cumana on sunflower ...

    African Journals Online (AJOL)

    Orobanche cumana broomrape is a parasitic plant described as an agricultural problem for sunflower production in many countries. In Tunisia, this pathogen was found parasitizing sunflower cultivars in some fields in the Béja region, for the first time during the 2009-2010 agricultural season. Clear O. cumana attachments ...

  6. A role for IAA in the infection of Arabidopsis thaliana by Orobanche aegyptiaca.

    Science.gov (United States)

    Bar-Nun, Nurit; Sachs, Tsvi; Mayer, Alfred M

    2008-01-01

    Vascular continuity is established between a host plant and the root parasite broomrape. It is generally accepted that the direction of vascular continuity results from polar flow of auxin. Our hypothesis was that chemical disruptions of auxin transport and activity could influence the infection of the host by the parasite. A sterile system for the routine infection of Arabidopsis thaliana seedlings in Nunc cell culture plates by germinated seeds of Orobanche aegyptiaca was developed. This method permitted a quantitative assay of the rate of host infection. The three-dimensional structure of the vascular contacts was followed in cleared tissue. IAA (indole acetic acid) or substances that influence its activity and transport were applied locally to the host root. The orientation of the xylem contacts showed that broomrape grafts itself upon the host by acting hormonally as a root rather than a shoot. Local applications of IAA, PCIB (p-chlorophenoxyisobutyric acid) or NPA (naphthylphthalamic acid) all resulted in drastic reductions of Orobanche infection Broomrape manipulates the host by acting as a sink for auxin. Disruption of auxin action or auxin flow at the contact site could be a novel basis for controlling infection by Orobanche.

  7. A peroxidase gene expressed during early developmental stages of the parasitic plant Orobanche ramosa.

    Science.gov (United States)

    González-Verdejo, Clara Isabel; Barandiaran, Xabier; Moreno, Maria Teresa; Cubero, José Ignacio; Di Pietro, Antonio

    2006-01-01

    Broomrapes (Orobanche spp.) are holoparasitic weeds that cause devastating losses in many economically important crops. The molecular mechanisms that control the early stages of host infection in Orobanche are poorly understood. In the present study, the role of peroxidase has been examined during pre-infection growth and development of O. ramosa, using an in vitro model system. Peroxidase activity was histochemically localized at the tips of actively growing radicles and nascent attachment organs. Addition of exogenous catalase resulted in a significant reduction in the apical growth rate of the radicle. The prx1 gene encoding a putative class III peroxidase was cloned from a cDNA library of O. ramosa and was found to be expressed specifically during the early stages of the parasitic life cycle. The exogenous addition of sucrose resulted in significantly reduced prx1 transcript levels and in a dramatic change in radicle development from polarized apical growth to isotropic growth and the formation of tubercle-like structures. The results indicate an important role of peroxidases during the early parasitic stages of Orobanche.

  8. Orobanche montserratii A. Pujadas & D. Gómez (Orobanchaceae, especie nueva del Pirineo oscense

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    Gómez García, Daniel

    1999-12-01

    Full Text Available Orobanche montserratii A. Pujadas & D. Gómez a new species of the spanish Pyrenees is described. The diagnosis, description, original illustration and the analysis of the morphological differences between the new species and O. alsatica Kirschl., O. bartlingü Griseb, and O. mayeri (Suess. & Ronniger Bertsch & F. Bertsch, are given.Se describe una nueva especie localizada en el Pirineo español. Aportamos su diagnosis, descripción, iconografía original y el análisis de los caracteres que permiten su diferenciación de Orobanche alsatica Kirschl., O. bartlingü Griseb, y O. mayeri (Suess. & Ronniger Bertsch & F. Bertsch.

  9. Effects of Arbuscular Mycorrhizal Symbiosis (Glomus intraradice on Egyptian Broomrape (Orobanche aegyptiaca. Pers in Cultivated Tomato (Lycopersicon esculentum Mill.

    Directory of Open Access Journals (Sweden)

    mojtaba zafarian

    2017-03-01

    Full Text Available Introduction: Mycorrhizal symbiosis is one of the most popular and highest symbiotic relationship in plant kingdom. Most plants (about 80% of vascular plant species have at least one type of mycorrhiza. Arbuscular mycorrhizal fungies are the most important endomycorhiza fungi that play an important role in agriculture. Materials and Methods: In order to evaluate the effect of arbuscular mycorrhizal (Glomus intraradice symbiosis to control Egyptian Broomrape (Orobanche aegyptiaca. Pers in cultivated tomato (Lycopersicon esculentum Mill. growth, a glasshouse experiment was conducted in CRD design with four replications in Shahrekord university in summer 2014. Treatments consisted of four arbuscular mycorrhizal levels (50, 100, 150 and 200 kg ha-1 and two control treatments of weed free and weed infested treatments, respectively. In this experiment, seeds of speedy tomato cultivar planted in the bed that consisted of coco peat and peat moss were transplanted to the pots. Pots with diameter 20 and height 15 cm were filled with soil in the ratio 4: 1: 1 manure, sand and clay respectively and with 50 mg of Orobanche seeds that were collected in the previous year. It should be noted that the soil combination was disinfected at a temperature of 80OC for 72 h to reduce the potential effects of soil microbial population in reducing Orobanche germination. The fungal inoculation, containing sandy soil fungal body parts and organs fungal root was then added to each pot. Fungi strain was provided from the plant protection clinic located in Hamadan. Also, nutrition of tomato after being transplanted to pots was carried out with foliar application of complete micronutrient of 20-20-20 every 7 days under glasshouse condition. At the end of the season, were measured number of stems, number of nodules on the roots of tomato, time of emergence of orobanche flower on the soil surface, orobanche dry weight and tomato root and shoot dry weight. Statistical analysis of

  10. Biosynthesis of germination stimulants of parasitic weeds Striga and Orobanche

    NARCIS (Netherlands)

    Sun, Z.

    2008-01-01

    My research focused on the biosynthetic origin of germination stimulants of the root parasitic plants, Striga spp. and Orobanche spp., which have an increasing impact on cereal and other economically important crops in many regions of the world. The traditional control methods are not sufficient and

  11. Analgesic and anticonvulsant effects of extracts from the leaves of Kalanchoe crenata (Andrews) Haworth (Crassulaceae).

    Science.gov (United States)

    Nguelefack, T B; Nana, P; Atsamo, A D; Dimo, T; Watcho, P; Dongmo, A B; Tapondjou, L A; Njamen, D; Wansi, S L; Kamanyi, A

    2006-06-15

    Kalanchoe crenata Andr. (Crassulaceae) is a fleshy herbaceous plant used in the African traditional medicine as remedies against otitis, headache, inflammations, convulsions and general debility. In the present work, the analgesic effects of methylene chloride/methanol (1:1) (CH(2)Cl(2)/CH(3)OH) extract and its hexane, methylene chloride (CH(2)Cl(2)), ethyl acetate, n-butanol fractions and aqueous residue have been evaluated using acetic acid, formalin and pressure test. The anticonvulsant effects of the CH(2)Cl(2)/CH(3)OH extract were also investigated on seizures induced by pentylenetetrazol (PTZ 70 mg/kg), strychnine sulphate (STN 2.5 mg/kg) and thiosemicarbazide (TSC 50 mg/kg). CH(2)Cl(2)/CH(3)OH extract and its fractions, administered orally at the doses of 150 and 300 mg/kg, exhibited protective effect of at least 30% on the pain induced by acetic acid. The CH(2)Cl(2) fraction at 300 mg/kg showed a maximal effect of 78.49%. The CH(2)Cl(2)/CH(3)OH extract and its CH(2)Cl(2) fraction at the doses of 150 and 300 mg/kg significantly reduced the first phase of pain induced by formalin while the second phase was completely inhibited. The CH(2)Cl(2) fraction produced more than 45% reduction in the sensitivity to pain induced by pressure. The CH(2)Cl(2)/CH(3)OH extract of Kalanchoe crenata significantly increased the latency period in seizures induced by PTZ and significantly reduced the duration of seizures induced by the three convulsant agents. The extract protected 20% of animals against death in seizures induced by TSC and STN. These results suggest a peripheral and central analgesic activities as well as an anticonvulsant effect of the leaves of Kalanchoe crenata.

  12. Susceptibility of the tomato mutant high pigment-2dg (hp-2dg) to Orobanche spp. infection.

    Science.gov (United States)

    López-Ráez, Juan Antonio; Charnikhova, Tatsiana; Mulder, Patrick; Kohlen, Wouter; Bino, Raoul; Levin, Ilan; Bouwmeester, Harro

    2008-08-13

    The consumption of natural products with potential health benefits has been continuously growing, and enhanced pigmentation is of major economic importance in fruits and vegetables. The tomato hp-2 ( dg ) is an important mutant line that has been introgressed into commercial tomato cultivars marketed as lycopene rich tomatoes (LRT) because of their enhanced fruit pigmentation, attributed to higher levels of carotenoids, including lycopene. Strigolactones are signaling compounds that mediate host finding in root parasitic plants and are biosynthetically derived from carotenoids. Considering the high carotenoid content of the hp-2 ( dg ) mutant, we studied its susceptibility to the root parasite Orobanche. In a field experiment, the average number of Orobanche aegyptiaca plants growing on hp-2 ( dg ) was surprisingly significantly reduced compared with its isogenic wild-type counterpart. In vitro assays and LC-MS/MS analysis showed that this reduction was associated with a lower production of strigolactones, which apparently renders the high-carotenoid hp-2 ( dg ) mutant less susceptible to Orobanche.

  13. Molecular responses of Lotus japonicus to parasitism by the compatible species Orobanche aegyptiaca and the incompatible species Striga hermonthica.

    Science.gov (United States)

    Hiraoka, Yukihiro; Ueda, Hiroaki; Sugimoto, Yukihiro

    2009-01-01

    Lotus japonicus genes responsive to parasitism by the compatible species Orobanche aegyptiaca and the incompatible species Striga hermonthica were isolated by using the suppression subtractive hybridization (SSH) strategy. O. aegyptiaca and S. hermonthica parasitism specifically induced the expression of genes involved in jasmonic acid (JA) biosynthesis and phytoalexin biosynthesis, respectively. Nodulation-related genes were almost exclusively found among the Orobanche-induced genes. Temporal gene expression analyses revealed that 19 out of the 48 Orobanche-induced genes and 5 out of the 48 Striga-induced genes were up-regulated at 1 dai. Four genes, including putative trypsin protease inhibitor genes, exhibited systemic up-regulation in the host plant parasitized by O. aegyptiaca. On the other hand, S. hermonthica attachment did not induce systemic gene expression.

  14. The distribution and habitat requirements of the genus Orobanche L. (Orobanchaceae in SE Poland

    Directory of Open Access Journals (Sweden)

    Renata Piwowarczyk

    2011-05-01

    Full Text Available The distribution of the genus Orobanche in SE Poland is presented. The study area stretches between the Vistula and the Bug rivers, and comprises the Polish areas of the Lublin-Lwów Upland, the Wołyń Upland and the southern part of Polesie. Eight species of the genus Orobanche: O. alba, O. alsatica, O. arenaria, O. caryophyllacea, O. elatior, O. lutea, O. pallidiflora, O. picridis, were collected during floristic investigations conducted between 1999 and 2010. The hosts, abundance and habitat preferences at the localities are given and a supplemented map of the distribution in SE Poland is included.

  15. Orobanche teucrii Holandre, primeras citas para el País Vasco

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    Juan Manuel Pérez de Ana.

    2011-01-01

    Full Text Available Orobanche teucrii Holandre vive parasitando a Teucrium pyrenaicum L. en torno a los 900 m de altitud en pastos rocosos en dos montañas de Sierra Salvada: Txolope y Txarlazo, en Orduña (Bizkaia y Amurrio (Araba.

  16. Biochemical analysis of induced resistance in chickpea against broomrape (Orobanche foetida by rhizobia inoculation

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    Yassine MABROUK

    2016-05-01

    Full Text Available This study examined the capacity of Rhizobium sp. strain PchAZM to reduce parasitism of chickpea by Orobanche foetida under greenhouse conditions, and assessed the relative impact of rhizobia on the expression of chickpea defense response against broomrape. Growth chamber experiments using Petri dishes revealed that rhizobia infection on chickpea roots reduced broomrape seed germination, and restricted the broomrape attachment to host roots while retarding tubercle formation and development by the parasite. In pot experiments, chickpea roots inoculated with rhizobia reduced the total number of broomrape by up to 90%. Broomrape necrosis was observed both before and after parasite attachment to inoculated chickpea roots in Petri dishes and pot experiments. Reduction in infection was accompanied by enhanced levels of the defence-related enzymes phenylalanine ammonia lyase (PAL and peroxidase (POX. Increased levels of phenolics were recorded in the roots of rhizobia-inoculated plants grown in the presence of broomrape. The results suggest that rhizobia could be used for protection of chickpea against O. foetida.

  17. The Control of Broomrape (Orobanche aegyptiaca in Tomato (Lycopersicum esculentum Mill Farms

    Directory of Open Access Journals (Sweden)

    K. Shirdel

    2014-12-01

    Full Text Available Broomrape would have irreversible effects on tomatoes in all growth stages and the damage would be unrecoverable. In order to chemically control Orobanche spp with consumption of bio-fertilizer in tomato cultivation, an experiment as factorial based on complete randomized blocks design in three replications and 12 plots was carried out at a farm which is located in Mahabad city (Iran. In this experiment, the experimental factors were including: A- sulfosulfuron 35 g/ha in three levels (application, at 40 days after transplanting of seedlings, application at 60 days and after sample transplanting without any chemical spraying, B and C: bio- fertilizers, Barvar -2 and Nitrajin in two levels (application and non-application of bio-fertilizer, were taken place. The results showed that Sulfosulfuron treatment at the rate of 35 gr/ha, with- twice application of 40 and 60 days after transplanting of seedlings decreased the biomass of Orobanche aegyptiaca in surface level and also it was possible to decrease the biomass per tomato bush and Orobanche aegyptiaca biomass to amount of 75%, 57% and 60% respectively compare to the main treatment without applying any kind of spray application. The applied bio-fertilizer-2 decreased the amount of fruit and economical function of tomato. The applying phosphate biofertilizer-2 resulted in a decrease in economical function of Lycopersicum esculentum and number of ripen fruits. However none of the applied treatment was influential on diameter and weight of ripen fruits.

  18. Dehydrocostus lactone is exuded from sunflower roots and stimulates germination of the root parasite Orobanche cumana.

    Science.gov (United States)

    Joel, Daniel M; Chaudhuri, Swapan K; Plakhine, Dina; Ziadna, Hammam; Steffens, John C

    2011-05-01

    The germination of the obligate root parasites of the Orobanchaceae depends on the perception of chemical stimuli from host roots. Several compounds, collectively termed strigolactones, stimulate the germination of the various Orobanche species, but do not significantly elicit germination of Orobanche cumana, a specific parasite of sunflower. Phosphate starvation markedly decreased the stimulatory activity of sunflower root exudates toward O. cumana, and fluridone - an inhibitor of the carotenoid biosynthesis pathway - did not inhibit the production of the germination stimulant in both shoots and roots of young sunflower plants, indicating that the stimulant is not a strigolactone. We identified the natural germination stimulant from sunflower root exudates by bioassay-driven purification. Its chemical structure was elucidated as the guaianolide sesquiterpene lactone dehydrocostus lactone (DCL). Low DCL concentrations effectively stimulate the germination of O. cumana seeds but not of Phelipanche aegyptiaca (syn. Orobanche aegyptiaca). DCL and other sesquiterpene lactones were found in various plant organs, but were previously not known to be exuded to the rhizosphere where they can interact with other organisms. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. An improved axenic system for studying pre-infection development of the parasitic plant Orobanche ramosa.

    Science.gov (United States)

    González-Verdejo, Clara Isabel; Barandiaran, Xabier; Moreno, Maria Teresa; Cubero, Jose Ignacio; Di Pietro, Antonio

    2005-11-01

    Broomrapes (Orobanche spp.) are holoparasitic weeds that cause devastating losses in many economically important crops. The molecular mechanisms that control early stages of host infection in Orobanche are poorly understood, partly due to the lack of experimentally tractable in vitro systems that allow the efficient application of molecular tools. Here an improved axenic system for the analysis of pre-infection stages in O. ramosa in the absence of the host plant is described. An optimized protocol for seed disinfection, based on formaldehyde, was developed. Orobanche ramosa seeds were conditioned in Petri dishes with filter paper, stimulated by addition of the synthetic strigol analogue GR24, and the percentage of germination as well as attachment-organ formation was determined. Treatment of O. ramosa seeds with tobacco-root exudate or with GR24 resulted in highly reproducible germination rates around 70 %. A conditioning period of 8 d was both necessary and sufficient to allow optimal germination in response to GR24. Conditioned seeds that were dehydrated for several months remained fully responsive to GR24 without the need of a new conditioning period. Treatments as short as 5 min with GR24 were sufficient to fully and irreversibly induce the seed germination response. Approximately half of the germinated seeds initiated attachment-organ development. Similar rates of attachment organ induction were also detected in the rare cases of seeds that had germinated spontaneously on water. The results suggest that the conditioning period produces persistent changes in the seeds required for responsiveness to external stimulants. The rapid action of GR24 suggests that it may act via a receptor-mediated signalling mechanism. While germination in O. ramosa is induced by exogenous stimuli, attachment organ differentiation appears to be triggered by unknown endogenous signals. The new in vitro culture system will have useful applications for the molecular analysis of early

  20. Infection of tubercles of the parasitic weed Orobanche aegyptiaca by mycoherbicidal Fusarium species.

    Science.gov (United States)

    Cohen, Barry A; Amsellem, Ziva; Lev-Yadun, Simcha; Gressel, Jonathan

    2002-11-01

    Progression of the infection by host-specific strains of Fusarium oxysporum and Fusarium arthrosporioides of Orobanche aegyptiaca (Egyptian broomrape) tubercles attached to tomato roots was tracked using light, confocal and electron microscopy. Mycelia transformed with the gene for green fluorescent protein were viewed using a confocal microscope. Fungal penetration was preceded by a rapid loss of starch, with approx. 10 % remaining at 9 h and no measurable starch at 24 h. Penetration into the Orobanche tubercles began by 12 h after inoculation. Hyphae penetrated the outer six cell layers by 24 h, reaching the centre of the tubercles by 48 h and infecting nearly all cells by 72 h. Most of the infected tubercles were dead by 96 h. Breakdown of cell walls and the disintegration of cytoplasm in and around the infected cells occurred between 48 and 96 h. Lignin-like material increased in tubercle cells of infected tissues over time, but did not appear to be effective in limiting fungal penetration or spread. Callose, suberin, constitutive toxins and phytoalexins were not detected in infected tubercles, suggesting that there are no obvious defence mechanisms to overcome. Both Fusarium spp. pathogenic on Orobanche produced fumonisin-like ceramide synthase inhibitors, while fusaric acid was produced only by F. oxysporum in liquid culture. The organisms do not have sufficient virulence for field use (based on glasshouse testing), suggesting that virulence should be transgenically enhanced or additional isolates sought.

  1. Unique phytochrome responses of the holoparasitic plant Orobanche minor.

    Science.gov (United States)

    Takagi, Kazuteru; Okazawa, Atsushi; Wada, Yu; Mongkolchaiyaphruek, Anchaya; Fukusaki, Eiichiro; Yoneyama, Koichi; Takeuchi, Yasutomo; Kobayashi, Akio

    2009-06-01

    Holoparasitic plants such as Orobanche spp. have lost their photosynthetic ability, so photoresponses to optimize photosynthesis are not necessary in these plants. Photoresponses are also involved in the regulation of plant development but the photoresponses of holoparasites have not been characterized in detail. In this study, the phytochrome (phy)-related photoresponse of Orobanche minor was investigated. Its photoreceptor, phytochrome A (OmphyA), was also characterized. Light effects on germination, shoot elongation, anthocyanin biosynthesis, and OmphyA expression and subcellular localization were analyzed. Red light (R):far-red light (FR) reversible inhibition of O. minor seed germination demonstrated that phy-mediated responses are retained in this holoparasite. Shoot elongation was inhibited by FR but not by R. This pattern is unique among known patterns of plant photoresponses. Additionally, molecular analysis showed that OmphyA is able to respond to the light signals. Interestingly, the unique pattern of photoresponses in O. minor seems to have been modified for adaptation to its parasitic life cycle. We hypothesize that this alteration has resulted from the loss or alteration of some phy-signaling components. Elucidation of altered components in phy signaling in this parasite will provide useful information not only about its physiological characteristics but also about general plant photoreception systems.

  2. Micromorphological studies on seeds of orobanche species from the iberian peninsula and the balearic islands, and their systematic significance.

    Science.gov (United States)

    Plaza, L; Fernández, I; Juan, R; Pastor, J; Pujadas, A

    2004-07-01

    Previous research has made clear the intrinsic taxonomic difficulties in identifying species in the genus Orobanche. The aim of this study, therefore, was to investigate the systematic utility of seed characteristics. Light and scanning electron microscopy was used to examine the seeds of 33 taxa of Orobanche from the Iberian Peninsula and the Balearic Islands. Characters such as size, shape and ornamentation of the seeds were not found to be very useful in differentiation of taxa; however, other characters of the epidermal seed coat cells proved to be very helpful in this respect. Ornamentation of the periclinal walls could be used to discriminate four morphological types. Other features related to the anticlinal walls of the cells, such as thickness, presence/absence of a narrow trough, or relative depth, all contributed to the characterization of a large number of species. The usefulness of micromorphological studies on seeds of Orobanche in relation to differentiating taxa is demonstrated, and a key is provided to distinguish species or groups of species.

  3. Cryptic host-specific diversity among western hemisphere broomrapes (Orobanche s.l., Orobanchaceae).

    Science.gov (United States)

    Schneider, Adam C; Colwell, Alison E L; Schneeweiss, Gerald M; Baldwin, Bruce G

    2016-11-01

    The broomrapes, Orobanche sensu lato (Orobanchaceae), are common root parasites found across Eurasia, Africa and the Americas. All species native to the western hemisphere, recognized as Orobanche sections Gymnocaulis and Nothaphyllon, form a clade that has a centre of diversity in western North America, but also includes four disjunct species in central and southern South America. The wide ecological distribution coupled with moderate taxonomic diversity make this clade a valuable model system for studying the role, if any, of host-switching in driving the diversification of plant parasites. Two spacer regions of ribosomal nuclear DNA (ITS + ETS), three plastid regions and one low-copy nuclear gene were sampled from 163 exemplars of Orobanche from across the native geographic range in order to infer a detailed phylogeny. Together with comprehensive data on the parasites' native host ranges, associations between phylogenetic lineages and host specificity are tested. Within the two currently recognized species of O. sect. Gymnocaulis, seven strongly supported clades were found. While commonly sympatric, members of these clades each had unique host associations. Strong support for cryptic host-specific diversity was also found in sect. Nothaphyllon, while other taxonomic species were well supported. We also find strong evidence for multiple amphitropical dispersals from central North America into South America. Host-switching is an important driver of diversification in western hemisphere broomrapes, where host specificity has been grossly underestimated. More broadly, host specificity and host-switching probably play fundamental roles in the speciation of parasitic plants. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. Resurrection of the genus Aphyllon for New World broomrapes (Orobanche s.l., Orobanchaceae).

    Science.gov (United States)

    Schneider, Adam C

    2016-01-01

    Recent phylogenetic studies support a monophyletic clade of New World broomrapes (Orobanche sects. Gymnocaulis and Nothaphyllon) sister to the Old World genus Phelipanche. I place the New World taxa in the genus Aphyllon, propose 21 new combinations, and provide a list of currently accepted taxa.

  5. The distribution and habitat preferences of the declining species Orobanche arenaria Borkh at the northern limit of its geographical range

    Directory of Open Access Journals (Sweden)

    Renata Piwowarczyk

    2011-01-01

    Full Text Available Three new sites of Orobanche arenaria were discovered during floristic investigations in the Wyżyna Małopolska upland in central Poland. The new localities are concentrated in the Ponidzie area (Garb Pińczowski ridge and Niecka Połaniecka basin and form the northern limit of the geographical range of O. arenaria. The paper presents information on the distribution of Orobanche arenaria in Poland, the abundance at the sites and habitats occupied by the species.

  6. Orobanche pallidiflora Wimm. & Grab. in Poland: distribution, habitat and host preferences

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    Renata Piwowarczyk

    2011-01-01

    Full Text Available The paper presents ten new localities of Orobanche pallidiflora Wimm. & Grab. from Poland (Middle Roztocze, Równina Bełska plain, Wyżyna Malopolska upland, Góry Kaczawskie Mts and Western Bieszczady Mts. Information on hosts, abundance and habitat preferences at the new localities is given and a supplemented map of the distribution in Poland is included.

  7. Orobanche cernua Loefling Attenuates Ultraviolet B-mediated Photoaging in Human Dermal Fibroblasts.

    Science.gov (United States)

    Gao, Wei; Wang, Yu-Shuai; Qu, Zheng-Yi; Hwang, Eunson; Ngo, Hien T T; Wang, Ying-Ping; Bae, Jahyun; Yi, Tae-Hoo

    2018-02-15

    UV radiation is the primary cause of skin photoaging, which results in an increase in matrix metalloproteinases and degradation of collagen. Developing new natural antioxidant as photoprotective agents has become a popular area of research. Orobanche cernua Loefling is a parasitic plant that is rich in phenylethanoid glycosides (PhGs). This study investigated the photoprotective effects of the ethanolic extract of Orobanche cernua Loefling (OC) and its principal component acteoside on UVB-induced photoaging as well as their underlying molecular mechanisms in normal human dermal fibroblasts (NHDFs). Biological testing demonstrated that OC and acteoside possessed significant photoprotective activities, reducing MMP and IL-6 levels while improving type-I procollagen synthesis in UVB-irradiated NHDFs. Further study showed that the protective mechanisms were the improvement of transcription factor Nrf2-mediated antioxidant defensive system, suppression of MAPK/AP-1 and activation of the TGF-β/Smad pathway. Together, our results suggested that OC might be a promising antiphotoaging agent against UV radiation-induced skin damage. © 2018 The American Society of Photobiology.

  8. The dynamics of faba bean (Vicia faba L. parasitism by Orobanche foetida

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    Zouhaier ABBES

    2010-09-01

    Full Text Available Normal 0 14 false false false MicrosoftInternetExplorer4 The dynamics of Orobanche foetida parasitizing faba bean are examined using Petri dish experiments. Rates of broomrape seed germination and seedling attachment to the host roots were quantified on three resistant genotypes (the Egyptian line Giza 429, the Spanish cultivar Baraca, and the Tunisian cultivar Najeh [XBJ90.03-16-1-1-1] and the susceptible cv. Bachaar. The percentage of O. foetida seed germination (11 to 38% was lower near the roots of resistant host plants than it was near the roots of ‘Bachaar’ (67%. O. foetida parasitism was followed using three parametric logistic functions. In this way some major parameters of the infection process were quantified: the maximal number (Nmax and the maximal rate (Rmax of broomrape attachments to the host roots, the median time required for attachment (T50, the maximal percentage of established tubercles reaching the final growth stage at 70 days after inoculation (DAI (%max, and the maximal rate of established tubercle growth (R’max. Broomrape attachment was lower and slower in resistant plants, as indicated by low Nmax and Rmax values combined with high T50 values. Furthermore the precocity of the resistant genotypes was correlated with low attachment. The parameters %max and R’max did not discriminate the susceptible cultivar Bachaar from Giza 429 or Baraca. On the other hand, the %max and the R’max were lower in the ‘Najeh’ plants. The findings indicated that both low attachment and limited growth of established tubercles contributed to resistance in the Najeh cultivar.

  9. Resurrection of the genus Aphyllon for New World broomrapes (Orobanche s.l., Orobanchaceae

    Directory of Open Access Journals (Sweden)

    Adam C. Schneider

    2016-12-01

    Full Text Available Recent phylogenetic studies support a monophyletic clade of New World broomrapes (Orobanche sects. Gymnocaulis and Nothaphyllon sister to the Old World genus Phelipanche. I place the New World taxa in the genus Aphyllon, propose 21 new combinations, and provide a list of currently accepted taxa.

  10. Vindplaatsen van Distelbremraap [Orobanche reticulata subsp. pallidiflora (Wimm. & Grab.) Hayek] in verstoorde duinen

    NARCIS (Netherlands)

    Londo, Ger; Mounk, Joop

    2001-01-01

    About 30 years ago Orobanche reticulata was recorded on two sites in the dunes. The records were not accepted because the plants did not show the typical dark based glandular hairs. The rediscovery, after 28 years, of this rare species on one of those earlier dune localities led to the notion that

  11. Stimulation of Orobanche ramosa seed germination by fusicoccin derivatives: a structure-activity relationship study.

    Science.gov (United States)

    Evidente, Antonio; Andolfi, Anna; Fiore, Michele; Boari, Angela; Vurro, Maurizio

    2006-01-01

    A structure-activity relationship study was conducted assaying 25 natural analogues and derivatives of fusicoccin (FC), and cotylenol, the aglycone of cotylenins, for their ability to stimulate the seed germination of the parasitic species Orobanche ramosa. Some of the compounds tested proved to be highly active, being 8,9-isopropylidene of the corresponding FC aglycone and the dideacetyl derivative the most active FC derivatives. In both groups of glucosides and aglycones (including cotylenol), the most important structural feature to impart activity appears to be the presence of the primary hydroxy group at C-19. Furthermore, the functionalities and the conformation of the carbotricyclic ring proved to play a significant role. The dideacetyl derivative of FC, being easily and rapidly obtainable in high yield starting by FC, could be of interest for its practical application as a stimulant of Orobanche ramosa seed germination, inducing the "suicidal germination", an interesting approach for parasitic plant management.

  12. Gene silencing of mannose 6-phosphate reductase in the parasitic weed Orobanche aegyptiaca through the production of homologous dsRNA sequences in the host plant.

    Science.gov (United States)

    Aly, Radi; Cholakh, Hila; Joel, Daniel M; Leibman, Diana; Steinitz, Benjamin; Zelcer, Aaron; Naglis, Anna; Yarden, Oded; Gal-On, Amit

    2009-08-01

    Orobanche spp. (broomrape) are parasitic plants which subsist on the roots of a wide range of hosts, including tomato, causing severe losses in yield quality and quantity. Large amounts of mannitol accumulate in this parasitic weed during development. Mannose 6-phosphate reductase (M6PR) is a key enzyme in mannitol biosynthesis, and it has been suggested that mannitol accumulation may be very important for Orobanche development. Therefore, the Orobanche M6PR gene is a potential target for efforts to control this parasite. Transgenic tomato plants were produced bearing a gene construct containing a specific 277-bp fragment from Orobanche aegyptiaca M6PR-mRNA, in an inverted-repeat configuration. M6PR-siRNA was detected in three independent transgenic tomato lines in the R1 generation, but was not detected in the parasite. Quantitative RT-PCR analysis showed that the amount of endogenous M6PR mRNA in the tubercles and underground shoots of O. aegyptiaca grown on transgenic host plants was reduced by 60%-80%. Concomitant with M6PR mRNA suppression, there was a significant decrease in mannitol level and a significant increase in the percentage of dead O. aegyptiaca tubercles on the transgenic host plants. The detection of mir390, which is involved with cytoplasmic dsRNA processing, is the first indication of the existence of gene-silencing mechanisms in Orobanche spp. Gene silencing mechanisms are probably involved with the production of decreased levels of M6PR mRNA in the parasites grown on the transformed tomato lines.

  13. Stimulation of seed germination of Orobanche species by ophiobolin A and fusicoccin derivatives.

    Science.gov (United States)

    Fernández-Aparicio, Mónica; Andolfi, Anna; Cimmino, Alessio; Rubiales, Diego; Evidente, Antonio

    2008-09-24

    Various Orobanche species (broomrapes) are serious weed problems and cause severe reduction on yields in many important crops. Seeds of these parasitic weeds may remain dormant in the soil for many years until germination is stimulated by the release of a chemical signal by roots of a host plant. Some fungal metabolites, such as ophiobolin A and fusicoccin derivatives, were assayed to determine their capacity to stimulate the seed germination of several Orobanche species. The results obtained showed that the stimulation of seed germination is species-dependent and also affected by the concentration of the stimulant. Among ophiobolin A, fusicoccin, and its seven derivatives, tested in the concentration range of 10 (-4)-10 (-7) M, the highest stimulatory effect was observed for ophiobolin A and the hexacetyl and pentacetyl isomers of 16- O-demethyl-de- tert-pentenylfusicoccin prepared by chemical modification of the fusicoccin, while the other fusicoccin derivatives appeared to be practically inactive. The most sensitive species appeared to be O. aegyptica, O. cumana, O. minor, and to a lesser extent, O. ramosa.

  14. Host-driven divergence in the parasitic plant Orobanche minor Sm. (Orobanchaceae).

    Science.gov (United States)

    Thorogood, C J; Rumsey, F J; Harris, S A; Hiscock, S J

    2008-10-01

    Many parasitic angiosperms have a broad host range and are therefore considered to be host generalists. Orobanche minor is a nonphotosynthetic root parasite that attacks a range of hosts from taxonomically disparate families. In the present study, we show that O. minor sensu lato may comprise distinct, genetically divergent races isolated by the different ecologies of their hosts. Using a three-pronged approach, we tested the hypothesis that intraspecific taxa O. minor var. minor and O. minor ssp. maritima parasitizing either clover (Trifolium pratense) or sea carrot (Daucus carota ssp.gummifer), respectively, are in allopatric isolation. Morphometric analysis revealed evidence of divergence but this was insufficient to define discrete, host-specific taxa. Intersimple sequence repeat (ISSR) marker-based data provided stronger evidence of divergence, suggesting that populations were isolated from gene flow. Phylogenetic analysis, using sequence-characterized amplified region (SCAR) markers derived from ISSR loci, provided strong evidence for divergence by clearly differentiating sea carrot-specific clades and mixed-host clades. Low levels of intrapopulation SCAR marker sequence variation and floral morphology suggest that populations on different hosts are probably selfing and inbreeding. Morphologically cryptic Orobanche taxa may therefore be isolated from gene flow by host ecology. Together, these data suggest that host specificity may be an important driver of allopatric speciation in parasitic plants.

  15. Polyphenols, including the new Peapolyphenols A-C, from pea root exudates stimulate Orobanche foetida seed germination.

    Science.gov (United States)

    Evidente, Antonio; Cimmino, Alessio; Fernández-Aparicio, Monica; Andolfi, Anna; Rubiales, Diego; Motta, Andrea

    2010-03-10

    Three new polyphenols, named peapolyphenols A-C, together with an already well-known polyphenol and a chalcone (1-(2,4-dihydroxyphenyl)-3-hydroxy-3-(4-hydroxyphenyl)-1-propanone and 1-(2,4-dihydroxyphenyl)-3-(4-methoxyphenyl)propenone) were isolated from pea root exudates. They were found to strongly stimulate Orobanche and Phelipanche species seed germination. Interestingly, only peapolyphenol A, 1,3,3-substituted propanone, and 1,3-disubstituted propenone had specific stimulatory activity on O. foetida, excluding any other Orobanche or Phelipanche species tested. This species specificity is relevant, as O. foetida does not respond to the synthetic strigolactone analogue GR24, commonly used as a standard for germination assays. As characterized by spectroscopic methods, peapolyphenols A-C proved to be differently functionalized polyphenols with hydroxy and methoxy groups on both the aromatic rings and the propyl chain.

  16. Orobanche flava Mart. ex F.W. Schultz (Orobanchaceae: en la Península Ibérica

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    Pujadas Salvá, Antonio J.

    2003-12-01

    Full Text Available Orobanche flava is reported in the N of the Iberian Península. Its diversity and distribution is analyzed for the península: var. flava in the Pyrenees and var. albicans Rhiner in the Cantabrian Mountain chain. Lectotypification of O. flava var. albicans Rhiner [ZT] is proposed. To facilítate the identification of O. flava we emphasize its differential morphological characters and an original icon is contributed.Se indica la presencia de Orobanche flava en el N de la Península Ibérica. Se analiza su diversidad y su distribución en el territorio: var. flava en el Pirineo y var. albicans Rhiner en la Cordillera Cantábrica. Se propone el lectótipo de O. flava var. albicans Rhiner [ZT]. Para facilitar la identificación de O. flava destacamos sus caracteres morfológicos diferenciales y aportamos un icono original.

  17. A new phenylethanoid glycoside from Orobanche cernua Loefling.

    Science.gov (United States)

    Qu, Zheng-yi; Zhang, Yu-wei; Zheng, Si-Wen; Yao, Chun-lin; Jin, Yin-ping; Zheng, Pei-he; Sun, Cheng-he; Wang, Ying-ping

    2016-01-01

    A novel phenylethanoid glycoside, 3'-O-methyl isocrenatoside (1), along with two known compounds, methyl caffeate (2) and protocatechuic aldehyde (3), were isolated from the fresh whole plant of Orobanche cernua Loefling. All the isolated compounds (1-3) were elucidated on the basis of spectroscopic analysis including IR, MS and NMR data. The cytotoxic activities of these compounds were evaluated. Results showed that 3'-O-methyl isocrenatoside (1) and methyl caffeate (2) exhibited significant cytotoxicity, with IC50 values of 71.89, 36.97 μg/mL and 32.32, 34.58 μg/mL against the B16F10 murine melanoma and Lewis lung carcinoma cell lines, respectively.

  18. Orobanche olbiensis (Coss. Nyman, taxon minusvalorado del Mediterráneo

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    Pujadas Salvà, Antonio J.

    2000-12-01

    Full Text Available Orobanche olbiensis is reported for the first time in the Iberian flora. growing on coastal sand-dune ecosystems of Alicante province (southeastern Spain. This taxon was neglected by most of European authors. probably due to its affinity to O.mutelii, with which it has been usually misidentified. A detailed description and drawing of the Alicantine plants are presented, and data on their ecology, phytosociology and distribution are also reported. Main differencess with O. mutelii are pointed out in an identification key.

    Se indica, por primera vez para la flora ibérica. la presencia de Orobanche olbiensis, a partir de poblaciones localizadas en ecosistemas dunares costeros de la provincia de Alicante. Se trata de un taxon que ha pasado desapercibido casi desde su descripción, probablemente por su afinidad con O. mutelii, planta con la que ha sido confundida. Se aporta una descripción e iconografía detalladas del material alicantino, así como datos sobre su ecología. fitosociología y distribución. Se destacan las diferencias más significativas con O.mutelii en una clave de identificación.

  19. De Centauriebremraap (Orobanche elatior Sutton) in Zuid-Limburg: een nieuwe soort voor de Nederlandse flora

    NARCIS (Netherlands)

    Kreutz, C.A.J.

    1989-01-01

    From 1973 onwards an Orobanche species was found repeatedly (though at intervals of several years) on a chalk slope in the South of Limburg. At first the plant was identified as O. lutea, but the author argues that in fact it is O. elatior. Presumably its host is Centaurea scabiosa.

  20. Heliolactone, a non-sesquiterpene lactone germination stimulant for root parasitic weeds from sunflower.

    Science.gov (United States)

    Ueno, Kotomi; Furumoto, Toshio; Umeda, Shuhei; Mizutani, Masaharu; Takikawa, Hirosato; Batchvarova, Rossitza; Sugimoto, Yukihiro

    2014-12-01

    Root exudates of sunflower (Helianthus annuus L.) line 2607A induced germination of seeds of root parasitic weeds Striga hermonthica, Orobanche cumana, Orobanche minor, Orobanche crenata, and Phelipanche aegyptiaca. Bioassay-guided purification led to the isolation of a germination stimulant designated as heliolactone. FT-MS analysis indicated a molecular formula of C20H24O6. Detailed NMR spectroscopic studies established a methylfuranone group, a common structural component of strigolactones connected to a methyl ester of a C14 carboxylic acid via an enol ether bridge. The cyclohexenone ring is identical to that of 3-oxo-α-ionol and the other part of the molecule corresponds to an oxidized carlactone at C-19. It is a carlactone-type molecule and functions as a germination stimulant for seeds of root parasitic weeds. Heliolactone induced seed germination of the above mentioned root parasitic weeds, while dehydrocostus lactone and costunolide, sesquiterpene lactones isolated from sunflower root exudates, were effective only on O. cumana and O. minor. Heliolactone production in aquacultures increased when sunflower seedlings were grown hydroponically in tap water and decreased on supplementation of the culture with either phosphorus or nitrogen. Costunolide, on the other hand, was detected at a higher concentration in well-nourished medium as opposed to nutrient-deficient media, thus suggesting a contrasting contribution of heliolactone and the sesquiterpene lactone to the germination of O. cumana under different soil fertility levels. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Orobanche mayeri (Suess. & Ronniger Bertsch & F. Bertsch – a species new to Poland

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    Renata Piwowarczyk

    2011-08-01

    Full Text Available Two new localities of Orobanche mayeri (Suess. & Ronniger Bertsch & F. Bertsch, one of the rarest representatives of the family Orobanchaceae in Europe, are reported from southern Poland. The species was recorded in the Pieniny Mts (Central Western Carpathians in July 2009. The hosts, abundance and habitat preferences at the new localities are described and a supplemented map of the distribution in Europe and Poland is given.

  2. A new method for in-situ monitoring of the underground development of Orobanche cumana in sunflower (Helianthus annuus) with a mini-rhizotron.

    Science.gov (United States)

    Eizenberg, H; Shtienberg, D; Silberbush, M; Ephrath, J E

    2005-11-01

    To develop an in-situ, non-destructive method for observation and monitoring of the underground developmental stages of the root parasite Orobanche cumana. The parasitic weed Orobanche causes severe damage to vegetables and field crops. Most of the damage caused to the crops occurs during the underground, unobservable parasitism stage. Sunflower (Helianthus annuus 'Adi') plants were planted in soil that was artificially inoculated with O. cumana seeds. Clear Plexiglas mini-rhizotron plastic observation tubes were inserted into the soil. Seed germination, early stage of penetration, and formation of tubercles and spikes were observed non-destructively and were monitored throughout the growing season by mean of a mini-rhizotron camera. Use of this technology enabled the complete individual parasite life cycle from the very early development (including germination) to Orobanche shoot to be monitored. In addition, the effect of the systemic herbicide Cadre (imazapic) on the development of O. cumana was inspected and quantified. This novel methodology facilitates the in-situ study of major aspects of the host-parasite interaction and of parasite suppression, such as parasitism dynamics, parasite growth rate, and the effect of chemical treatments on the parasite.

  3. Dose-response of seeds of the parasitic weeds Striga and Orobanche toward the synthetic germination stimulants GR24.

    NARCIS (Netherlands)

    Wigchert, S.C.M.; Kuiper, E.; Boelhouwer, G.J.; Nefkens, G.H.L.; Verkley, J.A.C.; Zwanenburg, B.

    1999-01-01

    Striga and Orobanche seeds germinate in response to a host-derived germination stimulant. Dose-response curves of the synthetic strigolactone analogues GR 24 and Nijmegen 1 were determined, and their activities were compared to that of the naturally occurring stimulant sorgolactone. Typical

  4. Phylogenetic position and taxonomy of the enigmatic Orobanche krylowii (Orobanchaceae), a predominatly Asian species newly found in Albania (SE Europe).

    Science.gov (United States)

    Frajman, Božo; Carlón, Luis; Kosachev, Petr; Pedraja, Oscar Sánchez; Schneeweiss, Gerald M; Schönswetter, Peter

    2013-10-11

    We report on the occurrence of Orobanche krylowii in the Alpet Shqiptare (Prokletije, Albanian Alps) mountain range in northern Albania (Balkan Peninsula). The species was previously known only from eastern-most Europe (Volga-Kama River in Russia), more than 2500 km away, and from adjacent Siberia and Central Asia. We used morphological evidence as well as nuclear ribosomal ITS sequences to show that the Albanian population indeed belongs to O. krylowii and that its closest relative is the European O. lycoctoni , but not O. elatior as assumed in the past. Both Orobanche krylowii and O. lycoctoni parasitize Ranunculaceae ( Thalictrum spp. and Aconitum lycoctonum , respectively). We provide an identification key and a taxonomic treatment for O. krylowii , and suggest the IUCN category CE (critically endangered) for the highly disjunct Albanian population.

  5. Orobanche flava (Orobanchaceae in Poland: current distribution, taxonomy, hosts and plant communities

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    Piwowarczyk Renata

    2014-06-01

    Full Text Available Orobanche flava is a species of Central European mountain ranges, mainly the Alps and Carpathian Mts. The paper presents the current distribution of O. flava in Poland based on a critical revision of herbarium and literature data as well as results of field investigations conducted between 1999 and 2014. The distribution of species is centered in southern Poland, mainly in the Carpathian Mts., and, sporadically, in the Sudeten Mts. The distribution of O. flava in Poland is mapped. The taxonomy, biology, and ecology are also discussed.

  6. Strigolactam: New potent strigolactone analogues for the germination of Orobanche cumana.

    Science.gov (United States)

    Lachia, Mathilde; Wolf, Hanno Christian; Jung, Pierre Joseph Marcel; Screpanti, Claudio; De Mesmaeker, Alain

    2015-01-01

    Very recently, strigolactones have been conclusively identified as phytohormones. The progresses achieved in this field are culminating in the identification of the molecular receptors involved in the signal transduction mechanism. The exact mechanism of the mode of action of strigolactones still remains to be fully elucidated and we were interested to gain some insight into the mechanism of action of strigolactones by selectively modifying the reactivity of the lactone C-ring. Therefore, we report here the synthesis of strigolactams 1 and 16 and their surprisingly good activity on the germination of Orobanche cumana parasitic weed seeds. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Strigolactone analogs derived from ketones using a working model for germination stimulants as a blueprint.

    Science.gov (United States)

    Mwakaboko, Alinanuswe S; Zwanenburg, Binne

    2011-04-01

    Strigolactones are important signaling compounds in the plant kingdom. Here we focus on their germination stimulatory effect on seeds of the parasitic weeds Striga and Orobanche spp. and more particularly on the design and synthesis of new active strigolactone analogs derived from simple cyclic ketones. New analogs derived from 1-indanone, 1-tetralone, cyclopentanone, cyclohexanone and a series of substituted cyclohexanones (including carvone and pulegone) are prepared by formylation of the ketones with ethyl formate followed by coupling with a halo butenolide. Both enantiomers of the analog derived from 1-tetralone have been prepared by employing a homochiral synthon for the coupling reaction. For three other strigolactone analogs the antipodes have been obtained by chromatography on a chiral column. All analogs have an appreciable germinating activity towards seeds of Striga hermomonthica and Orobanche crenata and O. cernua. Stereoisomers having the same configuration at the D-ring as in naturally occurring strigol have a higher stimulatory effect than the corresponding antipodes. The analogs obtained from 1-indanone and 1-tetralone have an activity comparable with that of the well known stimulant GR 24. Analogs derived from 2-phenyl-cylohexanone, carvone and pulegone also have a good germinating response. The results show that the working model for designing new bioactive strigolactones is applicable.

  8. The strigolactone germination stimulants of the plant-parasitic Striga and Orobanche spp. are derived from the carotenoid pathway

    NARCIS (Netherlands)

    Matusova, R.; Rani, K.; Verstappen, F.W.A.; Franssen, M.C.R.; Beale, M.; Bouwmeester, H.J.

    2005-01-01

    The seeds of parasitic plants of the genera Striga and Orobanche will only germinate after induction by a chemical signal exuded from the roots of their host. Up to now, several of these germination stimulants have been isolated and identified in the root exudates of a series of host plants of both

  9. Orobanche caryophyllacea Sm. (Orobanchaceae in Poland: current distribution, taxonomy, plant communities and hosts

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    Renata Piwowarczyk

    2014-09-01

    Full Text Available The paper presents the current distribution of Orobanche caryophyllacea Sm. in Poland based on a critical revision of herbarium and literature data as well as the results of my field studies. The majority of localities are in south and south-eastern Poland: Małopolska Upland, Lublin Upland, Roztocze, Przemyśl Foothills, Pieniny Mts, rarely in the valleys of the Lower Vistula and Oder rivers or Wolin island. The distribution map in Poland is included. The taxonomy, biology and ecology of the species are discussed.

  10. [Determination of phenylethanoid glycosides in Orobanche coerulescens].

    Science.gov (United States)

    Han, Guo-qing; Li, Cai-feng; Wang, Xiao-qin; Li, Min-hui; Li, Jing

    2015-11-01

    Orobanche caerulescens is an important medicinal resource in Orobanchaceae. The present study aims to establish methods for determination of acteoside, crenatoside, and total phenylethanoid glycosides in O. caerulescens, and determine the content in 15 samples to evaluate the resource utilization of this medicinal plant. The content of acteoside and crenatoside were quantitatively determined by HPLC, while total phenylpropanoid glycosides was estimated by UV-VIS spectrophotometry. According to the results, the content of acteoside was the highest in O. caerulescens, followed by crenatoside. The contents of acteoside, crenatoside, and total phenylethanoid glycosides were between 1.15% - 15.60%, 0.83% - 4.47%, and 6.78% - 27.43%, respectively, which had significant differences. The acquisition time has great influence on the content of main components of O. caerulescens. The content of phenylethanoid glycosides is higher in the samples which were collected at the flowering stage. The two determination methods were proved to be simple, accurate and reliable, and can be used to evaluate the quality and resource utilization of O. caerulescens.

  11. [A new phenethyl alcohol glycoside from Orobanche coerulescens].

    Science.gov (United States)

    Zhang, Qiang-Rong

    2017-03-01

    The constituents of the whole plant of Orobanche coerulescens were isolated and purified by using various column chromatographic techniques including D101, silica gel and ODS. The structures were identified by spectroscopic analyses including NMR and MS. A new phenylethanol glycoside was isolated from the whole plant of O. coerulescens, and was identified as 2-(3-methoxy-4-hydroxyphenyl)-ethanol-1-O- [(1→3)-O-α-L-rhamnopyranosyl-4, 6-O-di-feruloyl]-β-D-glucopyranoside, named as orobancheoside B. Through the antibacterial activity test, orobancheoside B was proved to have certain antibacterial activity, and be one of the main active components of O. coerulescens. The research result will laid a foundation for the medicinal materials and quality control research. Activity screening, broomrape orobancheoside B has certain antibacterial activity, as one of the main active components of O. coerulescens, and to constantly improve the quality of the medicinal materials laid a foundation. Copyright© by the Chinese Pharmaceutical Association.

  12. Purification and characterization of a beta-glucosidase from the root parasitic plant Orobanche minor Sm.

    Science.gov (United States)

    Sasanuma, Izumi; Hirakawa, Go

    2010-01-01

    The beta-glucosidase of a root parasitic angiosperm, Orobanche minor Sm., was purified and characterized. The optimum pH and temperature for activity of the enzyme were 5.0 and 50 degrees C. The beta-glucosidase was stable at up to 50 degrees C at pH 4.0-10.0. The M(r) was estimated to be 33 kD by SDS-PAGE. The enzyme hydrolyzed p-nitrophenyl-beta-D-glucopyranoside and salicin, but not the cell wall of O. minor or cellohexaose.

  13. Exogenous Cellulase Contributes to Mycoherbicidal Activity of Fusarium arthrosporioides on Orobanche aegyptiaca

    Directory of Open Access Journals (Sweden)

    Olubukola O. Babalola

    2010-01-01

    Full Text Available This paper investigates an association between the tubercle size of Orobanche aegyptiaca, tubercle death, and days to tubercle death in relation to cellulase-assisted mycoherbicide. Fusarium arthrosporioides killed 56% of tubercles when applied with cellulase compared to 35% when no cellulase was added. Death was inversely correlated with days over the two fungal treatment types. O. aegyptiaca tubercle size significantly correlated with the two other infection parameters studied. For F. arthrosporioides, only 9% (2 of the variation in days to death was explained by variation in tubercle size, whereas with cellulase it reaches 14%. In this study, mycelia of F. arthrosporioides did not show apparent damage to the tomato roots.

  14. Reduced germination of Orobanche cumana seeds in the presence of Arbuscular Mycorrhizal fungi or their exudates.

    Directory of Open Access Journals (Sweden)

    Johann Louarn

    Full Text Available Broomrapes (Orobanche and Phelipanche spp are parasitic plants responsible for important crop losses, and efficient procedures to control these pests are scarce. Biological control is one of the possible strategies to tackle these pests. Arbuscular Mycorrhizal (AM fungi are widespread soil microorganisms that live symbiotically with the roots of most plant species, and they have already been tested on sorghum for their ability to reduce infestation by witchweeds, another kind of parasitic plants. In this work AM fungi were evaluated as potential biocontrol agents against Orobanche cumana, a broomrape species that specifically attacks sunflower. When inoculated simultaneously with O. cumana seeds, AM fungi could offer a moderate level of protection against the broomrape. Interestingly, this protection did not only rely on a reduced production of parasitic seed germination stimulants, as was proposed in previous studies. Rather, mycorrhizal root exudates had a negative impact on the germination of O. cumana induced by germination stimulants. A similar effect could be obtained with AM spore exudates, establishing the fungal origin of at least part of the active compounds. Together, our results demonstrate that AM fungi themselves can lead to a reduced rate of parasitic seed germination, in addition to possible effects mediated by the mycorrhizal plant. Combined with the other benefits of AM symbiosis, these effects make AM fungi an attractive option for biological control of O. cumana.

  15. Reduced germination of Orobanche cumana seeds in the presence of Arbuscular Mycorrhizal fungi or their exudates.

    Science.gov (United States)

    Louarn, Johann; Carbonne, Francis; Delavault, Philippe; Bécard, Guillaume; Rochange, Soizic

    2012-01-01

    Broomrapes (Orobanche and Phelipanche spp) are parasitic plants responsible for important crop losses, and efficient procedures to control these pests are scarce. Biological control is one of the possible strategies to tackle these pests. Arbuscular Mycorrhizal (AM) fungi are widespread soil microorganisms that live symbiotically with the roots of most plant species, and they have already been tested on sorghum for their ability to reduce infestation by witchweeds, another kind of parasitic plants. In this work AM fungi were evaluated as potential biocontrol agents against Orobanche cumana, a broomrape species that specifically attacks sunflower. When inoculated simultaneously with O. cumana seeds, AM fungi could offer a moderate level of protection against the broomrape. Interestingly, this protection did not only rely on a reduced production of parasitic seed germination stimulants, as was proposed in previous studies. Rather, mycorrhizal root exudates had a negative impact on the germination of O. cumana induced by germination stimulants. A similar effect could be obtained with AM spore exudates, establishing the fungal origin of at least part of the active compounds. Together, our results demonstrate that AM fungi themselves can lead to a reduced rate of parasitic seed germination, in addition to possible effects mediated by the mycorrhizal plant. Combined with the other benefits of AM symbiosis, these effects make AM fungi an attractive option for biological control of O. cumana.

  16. Susceptibility of Phelipanche and Orobanche species to AAL-toxin.

    Science.gov (United States)

    de Zélicourt, Axel; Montiel, Grégory; Pouvreau, Jean-Bernard; Thoiron, Séverine; Delgrange, Sabine; Simier, Philippe; Delavault, Philippe

    2009-10-01

    Fusarium and Alternaria spp. are phytopathogenic fungi which are known to be virulent on broomrapes and to produce sphinganine-analog mycotoxins (SAMs). AAL-toxin is a SAM produced by Alternaria alternata which causes the inhibition of sphinganine N-acyltransferase, a key enzyme in sphingolipid biosynthesis, leading to accumulation of sphingoid bases. These long chain bases (LCBs) are determinant in the occurrence of programmed cell death (PCD) in susceptible plants. We showed that broomrapes are sensitive to AAL-toxin, which is not common plant behavior, and that AAL-toxin triggers cell death at the apex of the radicle as well as LCB accumulation and DNA laddering. We also demonstrated that three Lag1 homologs, encoding components of sphinganine N-acyltransferase in yeast, are present in the Orobanche cumana genome and two of them are mutated leading to an enhanced susceptibility to AAL-toxin. We therefore propose a model for the molecular mechanism governing broomrape susceptibility to the fungus Alternaria alternata.

  17. Recognition of Orobanche cumana Below-Ground Parasitism Through Physiological and Hyper Spectral Measurements in Sunflower (Helianthus annuus L.).

    Science.gov (United States)

    Cochavi, Amnon; Rapaport, Tal; Gendler, Tania; Karnieli, Arnon; Eizenberg, Hanan; Rachmilevitch, Shimon; Ephrath, Jhonathan E

    2017-01-01

    Broomrape ( Orobanche and Phelipanche spp.) parasitism is a severe problem in many crops worldwide, including in the Mediterranean basin. Most of the damage occurs during the sub-soil developmental stage of the parasite, by the time the parasite emerges from the ground, damage to the crop has already been done. One feasible method for sensing early, below-ground parasitism is through physiological measurements, which provide preliminary indications of slight changes in plant vitality and productivity. However, a complete physiological field survey is slow, costly and requires skilled manpower. In recent decades, visible to-shortwave infrared (VIS-SWIR) hyperspectral tools have exhibited great potential for faster, cheaper, simpler and non-destructive tracking of physiological changes. The advantage of VIS-SWIR is even greater when narrow-band signatures are analyzed with an advanced statistical technique, like a partial least squares regression (PLS-R). The technique can pinpoint the most physiologically sensitive wavebands across an entire spectrum, even in the presence of high levels of noise and collinearity. The current study evaluated a method for early detection of Orobanche cumana parasitism in sunflower that combines plant physiology, hyperspectral readings and PLS-R. Seeds of susceptible and resistant O. cumana sunflower varieties were planted in infested (15 mg kg -1 seeds) and non-infested soil. The plants were examined weekly to detect any physiological or structural changes; the examinations were accompanied by hyperspectral readings. During the early stage of the parasitism, significant differences between infected and non-infected sunflower plants were found in the reflectance of near and shortwave infrared areas. Physiological measurements revealed no differences between treatments until O. cumana inflorescences emerged. However, levels of several macro- and microelements tended to decrease during the early stage of O. cumana parasitism. Analysis of

  18. Recognition of Orobanche cumana Below-Ground Parasitism Through Physiological and Hyper Spectral Measurements in Sunflower (Helianthus annuus L.

    Directory of Open Access Journals (Sweden)

    Amnon Cochavi

    2017-06-01

    Full Text Available Broomrape (Orobanche and Phelipanche spp. parasitism is a severe problem in many crops worldwide, including in the Mediterranean basin. Most of the damage occurs during the sub-soil developmental stage of the parasite, by the time the parasite emerges from the ground, damage to the crop has already been done. One feasible method for sensing early, below-ground parasitism is through physiological measurements, which provide preliminary indications of slight changes in plant vitality and productivity. However, a complete physiological field survey is slow, costly and requires skilled manpower. In recent decades, visible to-shortwave infrared (VIS-SWIR hyperspectral tools have exhibited great potential for faster, cheaper, simpler and non-destructive tracking of physiological changes. The advantage of VIS-SWIR is even greater when narrow-band signatures are analyzed with an advanced statistical technique, like a partial least squares regression (PLS-R. The technique can pinpoint the most physiologically sensitive wavebands across an entire spectrum, even in the presence of high levels of noise and collinearity. The current study evaluated a method for early detection of Orobanche cumana parasitism in sunflower that combines plant physiology, hyperspectral readings and PLS-R. Seeds of susceptible and resistant O. cumana sunflower varieties were planted in infested (15 mg kg-1 seeds and non-infested soil. The plants were examined weekly to detect any physiological or structural changes; the examinations were accompanied by hyperspectral readings. During the early stage of the parasitism, significant differences between infected and non-infected sunflower plants were found in the reflectance of near and shortwave infrared areas. Physiological measurements revealed no differences between treatments until O. cumana inflorescences emerged. However, levels of several macro- and microelements tended to decrease during the early stage of O. cumana

  19. New locality of Orobanche coerulescens Stephan ex Willd. (Orobanchaceae at the NW limit of its geographical range

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    Renata Piwowarczyk

    2011-01-01

    Full Text Available A new locality of Orobanche coerulescens Stephan ex Willd. in the Wyżyna Małopolska upland (Garb Pińczowski hummock in central Poland is presented. Over 290 specimens were recorded in a xerothermic grassland of the class Festuco-Brometea comprising species of the class Koelerio glaucae-Corynephoretea canescentis on alkaline, sandy soil. O. coerulescens is extinct at the majority of its localities in Poland and only two localities are known at present.

  20. Increased Virulence in Sunflower Broomrape (Orobanche cumana Wallr.) Populations from Southern Spain Is Associated with Greater Genetic Diversity.

    Science.gov (United States)

    Martín-Sanz, Alberto; Malek, Jebri; Fernández-Martínez, José M; Pérez-Vich, Begoña; Velasco, Leonardo

    2016-01-01

    Orobanche cumana Wallr. (sunflower broomrape) is a holoparasitic weed that infects roots of sunflower in large areas of Europe and Asia. Two distant O. cumana gene pools have been identified in Spain, one in Cuenca province in the Center and another one in the Guadalquivir Valley in the South. Race F has been hypothesized to have arisen by separate mutational events in both gene pools. In the Guadalquivir Valley, race F spread in the middle 1990's to become predominant and contained so far with race F hybrids. Recently, enhanced virulent populations of O. cumana have been observed in commercial fields parasitizing race F resistant hybrids. From them, we collected four independent populations and conducted virulence and SSR marker-based genetic diversity analysis. Virulence essays confirmed that the four populations studied can parasitize most of the race F resistant hybrids tested, but they cannot parasitize the differential inbred lines DEB-2, carrying resistance to race F and G, and P-96, resistant to F but susceptible to races G from other countries. Accordingly, the new populations have been classified as race GGV to distinguish them from other races G. Cluster analysis with a set of populations from the two Spanish gene pools and from other areas, mainly Eastern Europe, confirmed that race GGV populations maintain close genetic relatedness with the Guadalquivir Valley gene pool. This suggested that increased virulence was not caused by new introductions from other countries. Genetic diversity parameters revealed that the four populations had much greater genetic diversity than conventional populations of the same area, containing only alleles present in the Guadalquivir Valley and Cuenca gene pools. The results suggested that increased virulence may have resulted from admixture of populations from the Guadalquivir Valley and Cuenca followed by recombination of avirulence genes.

  1. Increased Virulence in Sunflower Broomrape (Orobanche cumana Wallr. Populations from Southern Spain is Associated with Greater Genetic Diversity

    Directory of Open Access Journals (Sweden)

    Alberto eMartín-Sanz

    2016-05-01

    Full Text Available Orobanche cumana Wallr. (sunflower broomrape is a holoparasitic weed that infects roots of sunflower in large areas of Europe and Asia. Two distant O. cumana gene pools have been identified in Spain, one in Cuenca province in the Centre and another one in the Guadalquivir Valley in the South. Race F has been hypothesized to have arisen by separate mutational events in both gene pools. In the Guadalquivir Valley, race F spread in the middle 1990’s to become predominant and contained so far with race F hybrids. Recently, enhanced virulent populations of O. cumana have been observed in commercial fields parasitizing race F resistant hybrids. From them, we collected four independent populations and conducted virulence and SSR marker-based genetic diversity analysis. Virulence essays confirmed that the four populations studied can parasitize most of the race F resistant hybrids tested, but they cannot parasitize the differential inbred lines DEB-2, carrying resistance to race F and G and, and P-96, resistant to F but susceptible to races G from other countries. Accordingly, the new populations have been classified as race GGV to distinguish them from other races G. Cluster analysis with a set of populations from the two Spanish gene pools and from other areas, mainly Eastern Europe, confirmed that race GGV populations maintain close genetic relatedness with the Guadalquivir Valley gene pool. This suggested that increased virulence was not caused by new introductions from other countries. Genetic diversity parameters revealed that the four populations had much greater genetic diversity than conventional populations of the same area, containing only alleles present in the Guadalquivir Valley and Cuenca gene pools. The results suggested that increased virulence may have resulted from admixture of populations from the Guadalquivir Valley and Cuenca followed by recombination of avirulence genes.

  2. The Genetic Structure of Wild Orobanche cumana Wallr. (Orobanchaceae Populations in Eastern Bulgaria Reflects Introgressions from Weedy Populations

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    Rocío Pineda-Martos

    2014-01-01

    Full Text Available Orobanche cumana is a holoparasitic plant naturally distributed from central Asia to south-eastern Europe, where it parasitizes wild Asteraceae species. It is also an important parasitic weed of sunflower crops. The objective of this research was to investigate genetic diversity, population structure, and virulence on sunflower of O. cumana populations parasitizing wild plants in eastern Bulgaria. Fresh tissue of eight O. cumana populations and mature seeds of four of them were collected in situ on wild hosts. Genetic diversity and population structure were studied with SSR markers and compared to weedy populations. Two main gene pools were identified in Bulgarian populations, with most of the populations having intermediate characteristics. Cross-inoculation experiments revealed that O. cumana populations collected on wild species possessed similar ability to parasitize sunflower to those collected on sunflower. The results were explained on the basis of an effective genetic exchange between populations parasitizing sunflower crops and those parasitizing wild species. The occurrence of bidirectional gene flow may have an impact on wild populations, as new physiological races continuously emerge in weedy populations. Also, genetic variability of wild populations may favour the ability of weedy populations to overcome sunflower resistance mechanisms.

  3. The Genetic Structure of Wild Orobanche cumana Wallr. (Orobanchaceae) Populations in Eastern Bulgaria Reflects Introgressions from Weedy Populations

    Science.gov (United States)

    Pineda-Martos, Rocío; Pujadas-Salvà, Antonio J.; Fernández-Martínez, José M.; Stoyanov, Kiril; Pérez-Vich, Begoña

    2014-01-01

    Orobanche cumana is a holoparasitic plant naturally distributed from central Asia to south-eastern Europe, where it parasitizes wild Asteraceae species. It is also an important parasitic weed of sunflower crops. The objective of this research was to investigate genetic diversity, population structure, and virulence on sunflower of O. cumana populations parasitizing wild plants in eastern Bulgaria. Fresh tissue of eight O. cumana populations and mature seeds of four of them were collected in situ on wild hosts. Genetic diversity and population structure were studied with SSR markers and compared to weedy populations. Two main gene pools were identified in Bulgarian populations, with most of the populations having intermediate characteristics. Cross-inoculation experiments revealed that O. cumana populations collected on wild species possessed similar ability to parasitize sunflower to those collected on sunflower. The results were explained on the basis of an effective genetic exchange between populations parasitizing sunflower crops and those parasitizing wild species. The occurrence of bidirectional gene flow may have an impact on wild populations, as new physiological races continuously emerge in weedy populations. Also, genetic variability of wild populations may favour the ability of weedy populations to overcome sunflower resistance mechanisms. PMID:25143963

  4. Cytotoxicity of the methanol extracts of Elephantopus mollis, Kalanchoe crenata and 4 other Cameroonian medicinal plants towards human carcinoma cells.

    Science.gov (United States)

    Kuete, Victor; Fokou, Fabrice W; Karaosmanoğlu, Oğuzhan; Beng, Veronique P; Sivas, Hülya

    2017-05-25

    Cancer still constitutes one of the major health concerns globally, causing serious threats on patients, their families, and the healthcare system. In this study, the cytotoxicity of the methanol extract of Elephantopus mollis whole plant (EMW), Enantia chlorantha bark (ECB), Kalanchoe crenata leaves (KCL), Lophira alata bark (LAB), Millettia macrophylla leaves (MML) and Phragmanthera capitata leaves (PCL) towards five human solid cancer cell lines and normal CRL2120 fibroblasts, was evaluated. Extracts were subjected to qualitative chemical screening of their secondary metabolite contents using standard methods. The cytotoxicity of samples was evaluated using neutral red uptake (NR) assay meanwhile caspase activation was detected by caspase-Glo assay. Flow cytometry was used to analyze the cell cycle distribution and the mitochondrial membrane potential (MMP) whilst spectrophotometry was used to measure the levels of reactive oxygen species (ROS). Phytochemical analysis revealed the presence of polyphenols, triterpenes and sterols in all extracts. The IC 50 values of the best samples ranged from 3.29 μg/mL (towards DLD-1 colorectal adenocarcinoma cells) to 24.38 μg/mL (against small lung cancer A549 cells) for EMW, from 2.33 μg/mL (mesothelioma SPC212 cells) to 28.96 μg/mL (HepG2 hepatocarcinoma) for KCL, and from 0.04 μg/mL (towards SPC212 cells) to 0.55 μg/mL (towards A549 cells) for doxorubicin. EMW induced apoptosis in MCF-7 cells mediated by MMP loss and increased ROS production whilst KCL induced apoptosis via ROS production. This study provides evidences of the cytotoxicity of the tested plant extract and highlights the good activity of Elephantopus mollis and Kalanchoe crenata. They deserve more exploration to develop novel cytotoxic drugs.

  5. Changes in the activity of the alternative oxidase in Orobanche seeds during conditioning and their possible physiological function.

    Science.gov (United States)

    Bar Nun, Nurit; Plakhine, Dina; Joel, Daniel M; Mayer, Alfred M

    2003-09-01

    The appearance of the activity of the cyanide insensitive, alternative oxidase (AOX), pathway of oxygen uptake was followed in seeds of Orobanche aegyptiaca during conditioning. The pathway becomes operative during conditioning, up to day three as determined by inhibition of oxygen uptake of the seeds by propyl gallate. At the same time an increasing percentage of oxygen uptake is insensitive to cyanide and an increased oxygen uptake, responsive to propyl gallate, is induced by brief salicylic acid treatment of seeds. By day six of conditioning, these responses decrease and the AOX pathway could not be detected in germinating seeds, after treatment with a germination stimulant. These results were confirmed by following the reaction of extracts of fractions enriched with mitochondria from the conditioned seeds, using a specific antibody against AOX. Treatment of the seeds with inhibitors of AOX during conditioning significantly inhibited their subsequent germination. Addition of hydrogen peroxide after 4 and 7 days of conditioning resulted in reduced germination. In addition treatment of seed with propyl or octyl gallate during conditioning reduced the infection of tomato plants by Orobanche seeds and the development of tubercles of the parasite on the host roots. These results together indicate that the operation of AOX during conditioning has a significant function on the subsequent germination behaviour and pathogenicity of the root parasite. Some potential practical applications of these findings are discussed.

  6. A revision of distribution and historical analysis of preferred hosts of Orobanche ramosa (Orobanchaceae in Poland

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    Renata Piwowarczyk

    2012-12-01

    Full Text Available The Polish localities of Orobanche ramosa L., branched broomrape, are either extinct or have not been confirmed for many years. This paper presents two new localities of O. ramosa in Poland from the Płaskowyż Proszowicki plateau (Wyżyna Małopolska upland and the Nizina Nadwiślańska lowland (Kotlina Sandomierska basin. Habitat preferences and the abundance at the sites are described. A revised map of the distribution and a historical analysis of preferred hosts in Poland are included. The taxonomy, biology, ecology and control methods of O. ramosa are also discussed.

  7. Topical application of a cleanser containing extracts of Diospyros kaki folium, Polygonum cuspidatum and Castanea crenata var. dulcis reduces skin oil content and pore size in human skin

    OpenAIRE

    LEE, BO MI; AN, SUNGKWAN; KIM, SOO-YEON; HAN, HYUN JOO; JEONG, YU-JIN; LEE, KYOUNG-ROK; ROH, NAM KYUNG; AHN, KYU JOONG; AN, IN-SOOK; CHA, HWA JUN

    2015-01-01

    The effects of skin pores on skin topographic features can be reduced by decreasing excessive production and accumulation of sebum and elimination of comedones. Therefore, a cosmetic cleanser that regulates sebum homeostasis is required. In the present study, the effects of a cosmetic cleanser that contained Diospyros kaki folium, Polygonum cuspidatum and Castanea crenata var. dulcis (DPC) was examined on the removal of sebum and on skin pore size. Healthy volunteers (n=23) aged 20–50 years w...

  8. Trafficking of the potato spindle tuber viroid between tomato and Orobanche ramosa.

    Science.gov (United States)

    Vachev, T; Ivanova, D; Minkov, I; Tsagris, M; Gozmanova, M

    2010-04-10

    Viroids, small RNA pathogens capable of infecting flowering plants, coexist in the field with parasitic plants that infest many crops. The ability of viroids to be exchanged between host and parasitic plants and spread in the latter has not yet been investigated. We studied the interaction between the Potato spindle tuber viroid (PSTVd) and Branched bromrape (Orobanche ramosa) using the tomato, Solanum lycopersicon, as a common host. We report the long distance trafficking of PSTVd RNA via the phloem from tomato to O. ramosa, but not vice versa. Furthermore, we identify O. ramosa as a novel host with the ability to facilitate the replication and processing of PSTVd. Finally, molecular variants of PSTVd with single nucleotide substitutions that replicate with different efficiencies in tomato were isolated from O. ramosa. Copyright 2010 Elsevier Inc. All rights reserved.

  9. Hepatoprotective Effect of Essential Oils from Hyptis crenata in Sepsis-Induced Liver Dysfunction.

    Science.gov (United States)

    Lima, Glauber Cruz; Vasconcelos, Yuri de Abreu Gomes; de Santana Souza, Marilia Trindade; Oliveira, Alan Santos; Bomfim, Rangel Rodrigues; de Albuquerque Júnior, Ricardo Luiz Cavalcanti; Camargo, Enilton Aparecido; Portella, Viviane Gomes; Coelho-de-Souza, Andrelina Noronha; Diniz, Lúcio Ricardo Leite

    2018-02-28

    No specific therapeutics are available for the treatment of sepsis-induced liver dysfunction, a clinical complication strongly associated with the high mortality rate of septic patients. This study investigated the effect of the essential oil of Hyptis crenata (EOHc), a lamiaceae plant used to treat liver disturbances in Brazilian folk medicine, on liver function during early sepsis. Sepsis was induced by the cecal ligation and puncture (CLP) model. Rats were divided into four groups: Sham, Sham+EOHc, CLP, and CLP+EOHc. EOHc (300 mg/kg) was orally administered 12 and 24 h after surgery. The animals were sacrificed for blood collection and liver tissue samples 48 h after surgery. Hepatic function was evaluated by measuring serum bilirubin, alkaline phosphatase (ALP), aspartate aminotransferase, and alanine aminotransferase (ALT) levels. The levels of malondialdehyde and the activity of superoxide dismutase, catalase, and GSH peroxidase (GSH-Px) were measured for assessment of oxidative stress. Liver morphology was analyzed by hematoxylin and eosin staining. EOHc normalized serum ALP, ALT, and bilirubin levels and inhibited morphological changes. In addition, we observed that EOHc inhibited elevation in hepatic lipid peroxidation and reduction of the glutathione peroxidase activity induced by sepsis. Our data show that EOHc plays a protective effect against liver injury induced by sepsis.

  10. Biological control of Egyptian broomrape (Orobanche aegyptiaca using Fusarium spp.

    Directory of Open Access Journals (Sweden)

    I. Ghannam

    2007-08-01

    Full Text Available The broomrape (Orobanche spp. is an obligate holoparasitic weed that causes severe damage to many important vegetable crops. Many broomrape control strategies have been tested over the years. In this investigation, 125 Fusarium spp. isolates were recovered from diseased broomrape spikes collected from fields in agricultural areas near Hebron. The pathogenicity of isolates on broomrape was evaluated using an inoculum suspension containing mycelia and conidia. The most effective Fusarium isolates significantly increased the dead spikes of broomrape by 33.6–72.7% compared to the control; there was no obvious pathogenic effect on the tomato plants. Fusarium spp. isolates Fu 20, 25 and 119 were identified as F. solani, while Fu 30, 52, 59, 87 and 12-04 were F. oxysporum. In addition, the two previously known Fusarium strains, F. oxysporum strain EId (CNCM-I-1622 (Foxy and F. arthrosporioides strain E4a (CNCM-I-1621 (Farth were equally effective in controlling broomrape parasitizing tomato plants grown in pots, where the dead spikes of broomrape increased by 50.0 and 51.6%, respectively.

  11. Host-specific races in the holoparasitic angiosperm Orobanche minor: implications for speciation in parasitic plants.

    Science.gov (United States)

    Thorogood, C J; Rumsey, F J; Hiscock, S J

    2009-05-01

    Orobanche minor is a root-holoparasitic angiosperm that attacks a wide range of host species, including a number of commonly cultivated crops. The extent to which genetic divergence among natural populations of O. minor is influenced by host specificity has not been determined previously. Here, the host specificity of natural populations of O. minor is quantified for the first time, and evidence that this species may comprise distinct physiological races is provided. A tripartite approach was used to examine the physiological basis for the divergence of populations occurring on different hosts: (1) host-parasite interactions were cultivated in rhizotron bioassays in order to quantify the early stages of the infection and establishment processes; (2) using reciprocal-infection experiments, parasite races were cultivated on their natural and alien hosts, and their fitness determined in terms of biomass; and (3) the anatomy of the host-parasite interface was investigated using histochemical techniques, with a view to comparing the infection process on different hosts. Races occurring naturally on red clover (Trifolium pratense) and sea carrot (Daucus carota ssp. gummifer) showed distinct patterns of host specificity: parasites cultivated in cross-infection studies showed a higher fitness on their natural hosts, suggesting that races show local adaptation to specific hosts. In addition, histological evidence suggests that clover and carrot roots vary in their responses to infection. Different root anatomy and responses to infection may underpin a physiological basis for host specificity. It is speculated that host specificity may isolate races of Orobanche on different hosts, accelerating divergence and ultimately speciation in this genus. The rapid life cycle and broad host range of O. minor make this species an ideal model with which to study the interactions of parasitic plants with their host associates.

  12. Transforming a NEP1 toxin gene into two Fusarium spp. to enhance mycoherbicide activity on Orobanche--failure and success.

    Science.gov (United States)

    Meir, Sagit; Amsellem, Ziva; Al-Ahmad, Hani; Safran, Einat; Gressel, Jonathan

    2009-05-01

    The NEP1 gene encoding a fungal toxin that successfully conferred hypervirulence when transformed into Colletotrichum coccodes (Wallr.) Hughes attacking Abutilon theophrasti (L.) Medic. was tested to ascertain if it would enhance pathogenicity of Fusarium species to Orobanche aegyptiaca Pers. parasitising crops. None of the Fusarium oxysporum (#CNCM I-1622) NEP1 transformants was hypervirulent. NEP1 transformants of a new but unnamed Fusarium sp. (#CNCM I-1621--previously identified as F. arthrosporioides) killed Orobanche more rapidly than the wild type. Transformed lines of both species were NEP1 PCR positive, as was the wild type of F. oxysporum #CNCM I-1622 and five other formae speciales of F. oxysporum. All six wild-type formae speciales of F. oxysporum tested excrete minute amounts of immunologically and bioassay-detectable NEP1-like protein. NEP1 expression of most F. oxysporum transformants was suppressed, suggesting that the native gene and the transgene silence each other. The sequence of the putative NEP1 gene in Fusarium oxysporum #CNCM I-1622 differs from the sequence in the toxin-overproducing strain of F. oxysporum f. sp. erythroxyli in four or five amino acids in the first exon. Wild-type Fusarium sp. #CNCM I-1621 does not contain a NEP1-like gene, explaining why it seemed amenable to transformation with high expression, and its virulence was probably enhanced by not cosuppressing the endogenous gene as occurred with Fusarium oxysporum #CNCM I-1622.

  13. Investigation of Amino Acids As Herbicides for Control of Orobanche minor Parasitism in Red Clover.

    Science.gov (United States)

    Fernández-Aparicio, Mónica; Bernard, Alexandre; Falchetto, Laurent; Marget, Pascal; Chauvel, Bruno; Steinberg, Christian; Morris, Cindy E; Gibot-Leclerc, Stephanie; Boari, Angela; Vurro, Maurizio; Bohan, David A; Sands, David C; Reboud, Xavier

    2017-01-01

    Certain amino acids induce inhibitory effects in plant growth due to feedback inhibition of metabolic pathways. The inhibition patterns depend on plant species and the plant developmental stage. Those amino acids with inhibitory action on specific weeds could be utilized as herbicides, however, their use for weed control has not been put into practice. Orobanche minor is a weed that parasitizes red clover. O. minor germination is stimulated by clover root exudates. The subsequent seedling is an obligated parasite that must attach quickly to the clover root to withdraw its nutrients. Early development of O. minor is vulnerable to amino acid inhibition and therefore, a series of in vitro , rhizotron, and field experiments were conducted to investigate the potential of amino acids to inhibit O. minor parasitism. In in vitro experiments it was found that among a collection of 20 protein amino acids, lysine, methionine and tryptophan strongly interfere with O. minor early development. Field research confirmed their inhibitory effect but revealed that methionine was more effective than lysine and tryptophan, and that two successive methionine applications at 308 and 543 growing degree days inhibited O. minor emergence in red clover up to 67%. We investigated additional effects with potential to influence the practical use of amino acids against broomrape weeds, whether the herbicidal effect may be reversible by other amino acids exuded by host plants or may be amplified by inducing host resistance barriers against O. minor penetration. This paper suggests that amino acids may have the potential to be integrated into biorational programs of broomrape management.

  14. Investigation of Amino Acids As Herbicides for Control of Orobanche minor Parasitism in Red Clover

    Directory of Open Access Journals (Sweden)

    Mónica Fernández-Aparicio

    2017-05-01

    Full Text Available Certain amino acids induce inhibitory effects in plant growth due to feedback inhibition of metabolic pathways. The inhibition patterns depend on plant species and the plant developmental stage. Those amino acids with inhibitory action on specific weeds could be utilized as herbicides, however, their use for weed control has not been put into practice. Orobanche minor is a weed that parasitizes red clover. O. minor germination is stimulated by clover root exudates. The subsequent seedling is an obligated parasite that must attach quickly to the clover root to withdraw its nutrients. Early development of O. minor is vulnerable to amino acid inhibition and therefore, a series of in vitro, rhizotron, and field experiments were conducted to investigate the potential of amino acids to inhibit O. minor parasitism. In in vitro experiments it was found that among a collection of 20 protein amino acids, lysine, methionine and tryptophan strongly interfere with O. minor early development. Field research confirmed their inhibitory effect but revealed that methionine was more effective than lysine and tryptophan, and that two successive methionine applications at 308 and 543 growing degree days inhibited O. minor emergence in red clover up to 67%. We investigated additional effects with potential to influence the practical use of amino acids against broomrape weeds, whether the herbicidal effect may be reversible by other amino acids exuded by host plants or may be amplified by inducing host resistance barriers against O. minor penetration. This paper suggests that amino acids may have the potential to be integrated into biorational programs of broomrape management.

  15. Orobanche lutea Baumg. (Orobanchaceae in Poland: revised distribution, taxonomy, phytocoenological and host relations

    Directory of Open Access Journals (Sweden)

    Piwowarczyk Renata

    2014-06-01

    Full Text Available The paper presents current distribution of Orobanche lutea Baumg. in Poland based on a critical revision of herbarium and literature data as well as results of field investigations conducted between 1999-2014. Majority of localities are centred around the Silesia-Cracow, Małopolska and Lublin-Lviv Uplands. The greatest density of sites with probably the most abundant populations in Europe is in the central part of Silesia-Cracow Upland, which, by several hundred years, was heavily exploited for calamine mining (rich in zinc, lead and silver. This resulted in the formation of large areas of gangue containing toxic heavy metals. Since limestone, dolomite, marl and postglacial calcareous clay and sands occur there in most places, the soil is often strongly calcareous. Populations of O. lutea contain here many thousands of shoots. The distribution of the species in Poland is mapped. The taxonomy, biology, ecology and threats are also discussed.

  16. New sesquiterpene lactones from sunflower root exudate as germination stimulants for Orobanche cumana.

    Science.gov (United States)

    Raupp, Frank M; Spring, Otmar

    2013-11-06

    Orobanche cumana is a serious threat for cultivation of sunflower in Europe and Asia. Germination of the parasite is induced by metabolites released from the host root system. The first germination stimulant from sunflower root exudate was recently identified as dehydrocostus lactone, a sesquiterpene lactone. Bioassay-guided fractionation of root exudates now showed the release of additional sesquiterpene lactones. Besides dehydrocostus lactone, costunolide, tomentosin, and 8-epixanthatin were purified and identified spectroscopically. All four compounds induced germination of O. cumana at nano- to micromolar concentrations. Costunolide and dehydrocostus lactone concentrations above 1 μM reduced the activity, and application of 100 μM inhibited germination irreversibly. Seeds of Phelipanche ramosa could not be induced with costunolide. O. cumana seeds also germinated with GR24, a synthetic strigolactone. No bioactive fraction of sunflower contained compounds of this type. This supports previous findings that sesquiterpene lactones instead of strigolactones trigger the sunflower/O. cumana interaction.

  17. Cloning of a cryptochrome homologue from the holoparasitic plant Orobanche minor Sm.

    Science.gov (United States)

    Okazawa, Atsushi; Trakulnaleamsai, Chitra; Hiramatsu, Hiroya; Fukusaki, Ei'ichiro; Yoneyama, Koichi; Takeuchi, Yasutomo; Kobayashi, Akio

    2005-05-01

    Orobanche minor is a non-photosynthetic root holoparasitic plant. Although it is known that photosynthesis-related genes are inactivated or have been eliminated from the plastid genomes of holoparasites, little is known about the alterations in their genes involved in the signaling networks by which light regulates photosynthesis. Cryptochromes (crys), which are blue-light receptors, appear to control both photosynthesis-related and non-photosynthetic responses to light in higher plants. Because we are interested in to what extent a cry-mediated light signaling network remains in the holoparasites, we cloned CRY homologous cDNA from O. minor (OmCRY1) and used real-time RT-PCR to compare its expression under natural daylight and darkness. We found that the OmCRY1 has a high degree of homology with CRY1 s from photosynthetic plants. Expression of the OmCRY1 gene was higher in plants grown in the dark than that in the plants grown under natural daylight. This is the first report of the gene expression of a blue-light receptor in non-photosynthetic plants.

  18. Metabolites inhibiting germination of Orobanche ramosa seeds produced by Myrothecium verrucaria and Fusarium compactum.

    Science.gov (United States)

    Andolfi, Anna; Boari, Angela; Evidente, Antonio; Vurro, Maurizio

    2005-03-09

    Myrothecium verrucaria and Fusarium compactum were isolated from diseased Orobanche ramosa plants collected in southern Italy to find potential biocontrol agents of this parasitic weed. Both fungi grown in liquid culture produced metabolites that inhibited the germination of O. ramosa seeds at 1-10 muM. Eight metabolites were isolated from M. verrucaria culture extracts. The main metabolite was identified as verrucarin E, a disubstituted pyrrole not belonging to the trichothecene group. Seven compounds were identified by spectroscopic methods as macrocyclic trichothecenes, namely, verrucarins A, B, M, and L acetate, roridin A, isotrichoverrin B, and trichoverrol B. The main metabolite produced by F. compactum was neosoloaniol monoacetate, a trichothecene. All the trichothecenes proved to be potent inhibitors of O. ramosa seed germination and possess strong zootoxic activity when assayed on Artemia salina brine shrimps. Verrucarin E is inactive on both seed germination and zootoxic assay.

  19. Use of Blue-Green Fluorescence and Thermal Imaging in the Early Detection of Sunflower Infection by the Root Parasitic Weed Orobanche cumana Wallr.

    Science.gov (United States)

    Ortiz-Bustos, Carmen M; Pérez-Bueno, María L; Barón, Matilde; Molinero-Ruiz, Leire

    2017-01-01

    Although the impact of Orobanche cumana Wallr. on sunflower ( Helianthus annuus L.) becomes evident with emergence of broomrape shoots aboveground, infection occurs early after sowing, the host physiology being altered during underground parasite stages. Genetic resistance is the most effective control method and one of the main goals of sunflower breeding programmes. Blue-green fluorescence (BGF) and thermal imaging allow non-destructive monitoring of plant diseases, since they are sensitive to physiological disorders in plants. We analyzed the BGF emission by leaves of healthy sunflower plantlets, and we implemented BGF and thermal imaging in the detection of the infection by O. cumana during underground parasite development. Increases in BGF emission were observed in leaf pairs of healthy sunflowers during their development. Lower BGF was consistently detected in parasitized plants throughout leaf expansion and low pigment concentration was detected at final time, supporting the interpretation of a decrease in secondary metabolites upon infection. Parasite-induced stomatal closure and transpiration reduction were suggested by warmer leaves of inoculated sunflowers throughout the experiment. BGF imaging and thermography could be implemented for fast screening of sunflower breeding material. Both techniques are valuable approaches to assess the processes by which O. cumana alters physiology (secondary metabolism and photosynthesis) of sunflower.

  20. Use of Blue-Green Fluorescence and Thermal Imaging in the Early Detection of Sunflower Infection by the Root Parasitic Weed Orobanche cumana Wallr.

    Directory of Open Access Journals (Sweden)

    Carmen M. Ortiz-Bustos

    2017-05-01

    Full Text Available Although the impact of Orobanche cumana Wallr. on sunflower (Helianthus annuus L. becomes evident with emergence of broomrape shoots aboveground, infection occurs early after sowing, the host physiology being altered during underground parasite stages. Genetic resistance is the most effective control method and one of the main goals of sunflower breeding programmes. Blue-green fluorescence (BGF and thermal imaging allow non-destructive monitoring of plant diseases, since they are sensitive to physiological disorders in plants. We analyzed the BGF emission by leaves of healthy sunflower plantlets, and we implemented BGF and thermal imaging in the detection of the infection by O. cumana during underground parasite development. Increases in BGF emission were observed in leaf pairs of healthy sunflowers during their development. Lower BGF was consistently detected in parasitized plants throughout leaf expansion and low pigment concentration was detected at final time, supporting the interpretation of a decrease in secondary metabolites upon infection. Parasite-induced stomatal closure and transpiration reduction were suggested by warmer leaves of inoculated sunflowers throughout the experiment. BGF imaging and thermography could be implemented for fast screening of sunflower breeding material. Both techniques are valuable approaches to assess the processes by which O. cumana alters physiology (secondary metabolism and photosynthesis of sunflower.

  1. Specific developmental pathways underlie host specificity in the parasitic plant Orobanche

    Science.gov (United States)

    Hiscock, Simon

    2010-01-01

    Parasitic angiosperms are an ecologically and economically important group of plants. However our understanding of the basis for host specificity in these plants is embryonic. Recently we investigated host specificity in the parasitic angiosperm Orobanche minor, and demonstrated that this host generalist parasite comprises genetically defined races that are physiologically adapted to specific hosts. Populations occurring naturally on red clover (Trifolium pratense) and sea carrot (Daucus carota subsp. gummifer) respectively, showed distinct patterns of host specificity at various developmental stages, and a higher fitness on their natural hosts, suggesting these races are locally adapted. Here we discuss the implications of our findings from a broader perspective. We suggest that differences in signal responsiveness and perception by the parasite, as well as qualitative differences in signal production by the host, may elicit host specificity in this parasitic plant. Together with our earlier demonstration that these O. minor races are genetically distinct based on molecular markers, our recent data provide a snapshot of speciation in action, driven by host specificity. Indeed, host specificity may be an underestimated catalyst for speciation in parasitic plants generally. We propose that identifying host specific races using physiological techniques will complement conventional molecular marker-based approaches to provide a framework for delineating evolutionary relationships among cryptic host-specific parasitic plants. PMID:20081361

  2. Synthesis of strigolactones analogues by intramolecular [2+2] cycloaddition of ketene-iminium salts to olefins and their activity on Orobanche cumana seeds.

    Science.gov (United States)

    Lachia, Mathilde; Wolf, Hanno Christian; De Mesmaeker, Alain

    2014-05-01

    Strigolactones have been the latest identified phytohormones. Among the strigolactones analogues described recently, GR-24 remains the most studied derivative which is used as standard in this field. In order to improve several properties of GR-24 for potential agronomical applications, we investigated the effect of substituents on the B and C-rings on the activity for seed germination induction. We report here the synthesis of 9 GR-24 analogues via a [2+2] intramolecular cycloaddition of ketene-iminium salts and a summary of their activity for the germination of Orobanche cumana (broomrape) seeds. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Genetic divergence in nuclear genomes between populations of Fagus crenata along the Japan Sea and Pacific sides of Japan.

    Science.gov (United States)

    Hiraoka, Koichi; Tomaru, Nobuhiro

    2009-05-01

    Genetic diversity and structure in Fagus crenata were studied by analyzing 14 nuclear microsatellite loci in 23 populations distributed throughout the species' range. Although population differentiation was very low (F (ST) = 0.027; R (ST) = 0.041), both neighbor-joining tree and Bayesian clustering analyses provided clear evidence of genetic divergence between populations along the Japan Sea (Japan Sea lineage) and Pacific (Pacific lineage) sides of Japan, indicating that physical barriers to migration and gene flow, notably the mountain ranges separating the populations along the Japan Sea and Pacific sides, have promoted genetic divergence between these populations. The two lineages of the nuclear genome are generally consistent with those of the chloroplast genome detected in a previous study, with several discrepancies between the two genomes. Within-population genetic diversity was generally very high (average H (E) = 0.839), but decreased in a clinal fashion from southwest to northeast, largely among populations of the Japan Sea lineage. This geographical gradient may have resulted from the late-glacial and postglacial recolonization to the northeast, which led to a loss of within-population genetic diversity due to cumulative founder effects.

  4. Nitrogen and carbon relationships between the parasitic weed Orobanche foetida and susceptible and tolerant faba bean lines.

    Science.gov (United States)

    Abbes, Zouhaier; Kharrat, Mohamed; Delavault, Philippe; Chaïbi, Wided; Simier, Philippe

    2009-02-01

    The parasitic weed Orobanche foetida (Poiret) is an emergent agronomical problem on faba bean in Tunisia. The Tunisian breeding programs for faba bean resistance to O. foetida have produced several tolerant lines including the line XBJ90.03-16-1-1-1, which limits both parasite attachments to the host roots and growth of the attached parasites. The present study aims to provide a better understanding of the nutritional relationships between the parasite and this tolerant line in comparison with the susceptible Bachaar genotype. Phloem saps of faba bean were harvested using phloem exudation experiments. The major organic compounds potentially transferred from both faba bean genotypes to the parasite were identified as sucrose, raffinose, stachyose, citrate, malate, asparagine (ASN), aspartate (ASP), glutamine, glutamate, serine, alanine and GABA. However, the phloem exudates of the tolerant line were highly deficient in nitrogen when compared to that of the susceptible line. When attached to roots of the tolerant line, the parasite displayed limited activities of soluble invertases in tubercles, and especially in shoots, suggesting that the low performance of the broomrapes attached to the tolerant line resulted from a reduced capacity to utilize the host-derived carbohydrates. On the other hand, the mechanisms involved in the osmotic adjustment and primary metabolism of the parasite did not differ significantly according to the host genotype: mineral cations, especially potassium and calcium, predominated as the major osmotically-active compounds in both tubercles and shoots; shoots accumulated preferentially hexoses as organic solutes although tubercles accumulated preferentially starch and soluble amino acids, especially ASP and ASN. This suggests an important role for a glutamine-dependent asparagine synthetase (EC 6.3.5.4) in the N metabolism of the parasite.

  5. Lily Cultivars Have Allelopathic Potential in Controlling Orobanche aegyptiaca Persoon.

    Science.gov (United States)

    Chai, Min; Zhu, Xiaopei; Cui, Hongxia; Jiang, Chuangdao; Zhang, Jinzheng; Shi, Lei

    2015-01-01

    As a devastating holoparasitic weed, Orobanche aegyptiaca Persoon. (Egyptian broomrape) causes serious damage to agricultural production and threatens economic development, which has raised widespread concern. The present study was conducted to determine whether lilies have the potential to be used as 'trap crops' for controlling O. aegyptiaca Persoon. In the experiments, the ability of three popular lily cultivars (Lilium Oriental hybrids 'Sorbonne', Lilium LA (Longiflorum hybrids x Asiatic hybrids) hybrids 'Ceb Dazzle', and Lilium Longiflorum hybrids (L. formosanum x L. longiflorum) 'L. formolongo') to induce O. aegyptiaca Persoon. seed germination was assessed. Parts of the three lily cultivars, including the rhizosphere soil and underground and above-ground organs, all induced "suicidal germination" of parasitic O. aegyptiaca Persoon. seed at four growth stages. Specifically, Sorbonne and Ceb Dazzle behaved with similar allelopathy, and the bulb, scale leaf and aerial stem exhibited stronger allelopathic effects on O. aegyptiaca Pers. germination compared to other organs. Aqueous L. formolongo leaf extracts may contain more stable, effective stimulants given that they induced the highest germination rate at 76.7% even though the extracts were serially diluted. We speculate that these organs may be advantageous in further isolating and purifying economical active substances that can be substitutes for GR24. These results indicate that lilies have the potential to be used as a trap crops or can be processed into green herbicide formulations that can be applied in agriculture production to rapidly deplete the seed bank of O. aegyptiaca Persoon. parasitic weeds in soil.

  6. Lily Cultivars Have Allelopathic Potential in Controlling Orobanche aegyptiaca Persoon.

    Directory of Open Access Journals (Sweden)

    Min Chai

    Full Text Available As a devastating holoparasitic weed, Orobanche aegyptiaca Persoon. (Egyptian broomrape causes serious damage to agricultural production and threatens economic development, which has raised widespread concern. The present study was conducted to determine whether lilies have the potential to be used as 'trap crops' for controlling O. aegyptiaca Persoon. In the experiments, the ability of three popular lily cultivars (Lilium Oriental hybrids 'Sorbonne', Lilium LA (Longiflorum hybrids x Asiatic hybrids hybrids 'Ceb Dazzle', and Lilium Longiflorum hybrids (L. formosanum x L. longiflorum 'L. formolongo' to induce O. aegyptiaca Persoon. seed germination was assessed. Parts of the three lily cultivars, including the rhizosphere soil and underground and above-ground organs, all induced "suicidal germination" of parasitic O. aegyptiaca Persoon. seed at four growth stages. Specifically, Sorbonne and Ceb Dazzle behaved with similar allelopathy, and the bulb, scale leaf and aerial stem exhibited stronger allelopathic effects on O. aegyptiaca Pers. germination compared to other organs. Aqueous L. formolongo leaf extracts may contain more stable, effective stimulants given that they induced the highest germination rate at 76.7% even though the extracts were serially diluted. We speculate that these organs may be advantageous in further isolating and purifying economical active substances that can be substitutes for GR24. These results indicate that lilies have the potential to be used as a trap crops or can be processed into green herbicide formulations that can be applied in agriculture production to rapidly deplete the seed bank of O. aegyptiaca Persoon. parasitic weeds in soil.

  7. Research on resistance to sunflower broomrape: an integrated vision

    Directory of Open Access Journals (Sweden)

    Velasco Leonardo

    2016-03-01

    Full Text Available Sunflower broomrape (Orobanche cumana Wallr. parasitization on sunflower was first observed at the end of the 19th century and has continued since then jeopardizing sunflower cultivation in many areas of Europe and Asia. A distinctive characteristic of the O. cumana-sunflower parasitic system is that it is mainly governed by a gene-for-gene interaction. This determines complete resistance in the host controlled by dominant alleles at a single locus, which facilitates the management of the resistance for hybrid seed production. But on the other hand avirulence in the parasite is also controlled by dominant alleles at a single gene. Monogenic, dominant resistance exerts a strong selection pressure on the parasite that maximizes the probability of overcoming resistance mechanisms in a short period of time. This has in fact resulted in a number of physiological races that periodically surpass all the available resistance sources. The spread of populations to new areas and the subsequent hybridization between populations is another mechanism creating genetic diversity in sunflower broomrape and allegedly recombination of avirulences genes. After more than one century of coexistence, genetic resistance to broomrape in sunflower has to be focused under an integrated approach that considers not only the characterization of resistance mechanisms in the host, but also the genetic and physiological bases of avirulence in the parasite. From the perspective of genetic resistance in sunflower, most important is not relying only on single dominant genes, but following instead pyramiding strategies. These should give priority to combining complementary mechanisms of resistance under both qualitative (vertical and quantitative (horizontal genetic control. These aspects are discussed in the paper.

  8. A putative role for fusaric acid in biocontrol of the parasitic angiosperm Orobanche ramosa.

    Science.gov (United States)

    Bouizgarne, Brahim; El-Maarouf-Bouteau, Hayat; Madiona, Karine; Biligui, Bernadette; Monestiez, Michèle; Pennarun, Anne Marie; Amiar, Zahia; Rona, Jean Pierre; Ouhdouch, Yedir; El Hadrami, Ismaïl; Bouteau, François

    2006-05-01

    Fusarium spp. are ubiquitous fungi found in soil worldwide as both pathogenic and nonpathogenic strains. The signals leading to disease or the absence of disease are poorly understood. We recently showed that fusaric acid (FA), a nonspecific toxin produced by most Fusarium spp., could elicit various plant defense responses at 100 nM without toxic effect. In this study, we checked for the effect of FA on root and root hairs, probable first site of contact between the fungi and the host. Large FA concentrations reduce root and root-hair growth and induce a rapid transient membrane hyperpolarization, followed by a large depolarization, due to the inhibition of H(+)-ATPase currents. Nanomolar concentrations of FA induced only an early transient membrane hyperpolarization of root hairs compatible with the induction of a signal transduction pathway. FA at 10(-7) M failed to induce salicylic acid- and jasmonic acid/ethylene-dependent defense-related genes but inhibited the germination of the angiosperm parasite Orobanche ramosa in contact of FA-pretreated Arabidopsis thaliana seedlings. These data suggest that FA at nontoxic concentrations could activate signal transduction components necessary for plant-defense responses that could contribute to biocontrol activity of Fusarium spp.

  9. Confirmation and quantification of strigolactones, germination stimulants for root parasitic plants Striga and Orobanche, produced by cotton.

    Science.gov (United States)

    Sato, Daisuke; Awad, Ayman A; Takeuchi, Yasutomo; Yoneyama, Koichi

    2005-01-01

    The germination stimulants for root parasitic plants Striga and Orobanche produced by cotton (Gossypium hirsutum L.) were examined in detail. Seeds of cotton were germinated and grown on glass wool wetted with sterile distilled water in sterile filter units. The root exudate was collected daily and extracted with ethyl acetate. Each of these ethyl acetate extracts was analyzed directly by high-performance liquid chromatography linked with tandem mass spectrometry (LC/MS/MS). The results demonstrate that cotton roots exuded strigol and strigyl acetate, but no other known strigolactones such as orobanchol and alectrol. The production of strigol was detected even in the root exudate collected during the first 24 h of incubation and reached a maximum 5-7 days later. The average exudation of strigol and strigyl acetate during the incubation period was ca. 15 and 2 pg/plant/day, respectively, indicating that strigol mainly contributed to germination stimulation by the cotton root exudate.

  10. Horizontal gene transfer of a plastid gene in the non-photosynthetic flowering plants Orobanche and Phelipanche (Orobanchaceae).

    Science.gov (United States)

    Park, Jeong-Mi; Manen, Jean-François; Schneeweiss, Gerald M

    2007-06-01

    Plastid sequences are among the most widely used in phylogenetic and phylogeographic studies in flowering plants, where they are usually assumed to evolve like non-recombining, uniparentally transmitted, single-copy genes. Among others, this assumption can be violated by intracellular gene transfer (IGT) within cells or by the exchange of genes across mating barriers (horizontal gene transfer, HGT). We report on HGT of a plastid region including rps2, trnL-F, and rbcL in a group of non-photosynthetic flowering plants. Species of the parasitic broomrape genus Phelipanche harbor two copies of rps2, a plastid ribosomal gene, one corresponding to the phylogenetic position of the respective species, the other being horizontally acquired from the related broomrape genus Orobanche. While the vertically transmitted copies probably reside within the plastid genome, the localization of the horizontally acquired copies is not known. With both donor and recipient being parasitic plants, a possible pathway for the exchange of genetic material is via a commonly attacked host.

  11. Fluridone and norflurazon, carotenoid-biosynthesis inhibitors, promote seed conditioning and germination of the holoparasite Orobanche minor.

    Science.gov (United States)

    Chae, Sang Heon; Yoneyama, Koichi; Takeuchi, Yasutomo; Joel, Daniel M.

    2004-02-01

    Fluridone and norflurazon, two carotenoid-biosynthesis inhibitors, shortened the conditioning period required by seeds of Orobanche minor in order to respond to the germination stimulant strigol. Neither fluridone nor norflurazon alone induced seed germination of O. minor, they promoted strigol-induced germination. In addition, these compounds restored the conditioning and germination of seeds at a supraoptimal temperature (30 degrees C) as well as in the light. Gibberellic acid (GA(3)) showed similar promotive and protective effects on the conditioning and germination of O. minor seeds. Although fluridone and norflurazon are known to prevent abscisic acid (ABA)-biosynthesis, and stresses such as supraoptimal temperatures have been reported to induce ABA accumulation in plants, the amount of ABA in the seeds or that released from the seeds into the conditioning media was not affected by the fluridone treatment and by exposure to the supraoptimal temperature. These results indicate that the promotive and protective effects of fluridone and norflurazon on the conditioning and germination of O. minor seeds would be attributed to other perturbations rather than the inhibition of ABA-biosynthesis.

  12. Orobanche elatior and O. kochii (Orobanchaceae in Poland: distribution, taxonomy, plant communities and seed micromorphology

    Directory of Open Access Journals (Sweden)

    Renata Piwowarczyk

    2015-03-01

    Full Text Available Species of the genus Orobanche (Orobanchaceae, parasitic on Centaurea in Central Europe, were previously considered to belong to the O. elatior group. At present, the taxon is differentiated into two species, O. elatior Sutton and O. kochii F.W. Schultz. The paper presents for the first time the distribution of O. elatior and O. kochii in Poland based on a critical revision of herbarium and the literature data, as well as the results of field studies conducted between 1999 and 2014. The majority of the species’ localities are in south Poland: Silesia-Cracow, Małopolska and the Lublin Uplands. The distribution of both species in Poland is mapped and chronologically organized, and is thus the most recent in Europe. The taxonomy, host preferences, and ecology are also discussed. Seeds of both species were also investigated using light and scanning electron microscopy, which resulted in the designation of diagnostic features. The new color form of O. kochii f. citrina is described and illustrated. An account of all revised herbarium specimens collected from Poland, deposited in Poland and neighboring countries, is presented.

  13. Effect of fungal and plant metabolites on broomrapes (Orobanche and Phelipanche spp.) seed germination and radicle growth.

    Science.gov (United States)

    Cimmino, Alessio; Fernández-Aparicio, Mónica; Andolfi, Anna; Basso, Sara; Rubiales, Diego; Evidente, Antonio

    2014-10-29

    Orobanche and Phelipanche species (the broomrapes) are root parasitic plants, some of which cause heavy yield losses on important crops. The development of herbicides based on natural metabolites from microbial and plant origin, targeting early stages on parasitic plant development, might contribute to the reduction of broomrape seed bank in agricultural soils. Therefore, the effect of metabolites belonging to different classes of natural compounds on broomrape seed germination and radicle development was assayed in vitro. Among the metabolites tested, epi-sphaeropsidone, cyclopaldic acid, and those belonging to the sesquiterpene class induced broomrape germination in a species-specific manner. epi-Epoformin, sphaeropsidin A, and cytochalasans inhibited germination of GR24-treated broomrape seeds. The growth of broomrape radicle was strongly inhibited by sphaeropsidin A and compounds belonging to cyclohexene epoxide and cytochalasan classes. Broomrape radicles treated with epi-sphaeropsidone developed a layer of papillae while radicles treated with cytochalasans or with sphaeropsidin A turned necrotic. These findings allow new lead natural herbicides for the management of parasitic weeds to be identified.

  14. Isolation and characterization of a cDNA encoding phytochrome A in the non-photosynthetic parasitic plant, Orobanche minor Sm.

    Science.gov (United States)

    Trakulnaleamsai, Chitra; Okazawa, Atsushi; An, Chung-Il; Kajiyama, Shin'ichiro; Fukusaki, Ei'ichiro; Yoneyama, Koichi; Takeuchi, Yasutomo; Kobayashi, Akio

    2005-01-01

    In this study, the isolation and characterization of a phytochrome A (PHYA) homologous cDNA (OmPHYA) in the non-photosynthetic holoparasitic plant Orobanche minor are described. The present findings provide the first report of the presence of a PHYA homolog in the holoparasite. This study found that OmPHYA is of similar size to the other PHYAs of green plants and shows 72, 77, and 77% amino acid sequence identity with PHYA in Arabidopsis, potato, and tobacco respectively. The OmPHYA contains a conserved chromophore attachment cysteine at position 323. Although OmPHYA shows high sequence identity with other PHYAs in green plants, 13 amino acid substitutions located in both the N and C-terminal domains are observed (a total of 26 amino acids). OmPHYA is encoded by a single gene within the O. minor genome. The abundance of the OmPHYA transcript as well as nuclear translocation of OmphyA occurs in a light-dependent manner.

  15. A revision of distribution and the ecological description of Orobanche picridis (Orobanchaceae at the NE limit of its geographical range from Poland and Ukraine

    Directory of Open Access Journals (Sweden)

    Renata Piwowarczyk

    2012-12-01

    Full Text Available The paper presents the current distribution of Orobanche picridis in Poland and Ukraine, within the Polish borders in the interwar period, based on a critical revision of herbarium and literature data as well as the results of my field studies. The largest number of its localities is in S and SE Poland in the Wyżyna Śląsko-Krakowska, Wyżyna Małopolska, Wyżyna Lubelska uplands, Middle Roztocze, Small Polesie, the Pogórze Przemyskie foreland and in the former Tarnopol province (W Ukraine. These are the north-easternmost sites known for the species and extend its limit range. A map of its distribution in Poland and Ukraine is included. The taxonomy, biology, and ecology of O. picridis are also discussed.

  16. DESARROLLO DE UN PROTOCOLO DE PCR CUANTITATIVO EN TIEMPO REAL (QPCR), PARA LA DETECCION Y CUANTIFICACION DE MALEZAS HOLOPARASITAS CUARENTENARIAS (OROBANCHE SPP) QUE CONTAMINAN SEMILLAS Y SUELOS EN CHILE

    OpenAIRE

    Díaz Sánchez, Jorge Eduardo

    2013-01-01

    Las malezas parásitas del género Orobanche constituyen un grave problema para la agricultura a nivel mundial. Chile no está ajeno a esta situación, ya que O. ramosa y O. minor están invadiendo y estableciéndose en importantes zonas agrícolas. Es así como O. ramosa parásita a diversos cultivos (tomate, tabaco y papa) entre la Región Metropolitana y la Araucania (35° a 38° Lat. S) y O. minor a especies forrajeras (trébol, alfalfa y serradella) entre la Región del Maule a la Araucania (35° a 39°...

  17. Creating Sunflower Mutant Lines (Helianthus Annuus L.) Using Induced Mutagenesis

    International Nuclear Information System (INIS)

    Encheva, J.

    2009-01-01

    Immature sunflower zygotic embryos of sunflower fertility restorer line 374 R were treated with ultrasound and gamma radiation before plating embryos to culture medium. All plants were isolated and self-pollinated for several generations. New sunflower forms with inherited morphological and biochemical changes were obtained. The genetic changes occurring during the mutation procedure included fourteen morphological and biochemical characters. In comparison to the check line 374 R, decreasing of the mean value of the indexes was registered for 33 % of the total number of characters and vise verse, significant increasing was observed for 60 %. Mutation for resistance to the local population of Orobanche cumana race A-E was obtained from the susceptible Bulgarian control line 374 R. Two investigated mutant lines possessed 100 % resistance to Orobanche and stable inheritance in the next generations. Our results showed that induced mutagenesis in sunflower can be successfully used to develop new lines useful for heterosis breeding

  18. Strigolactone biosynthesis is evolutionarily conserved, regulated by phosphate starvation and contributes to resistance against phytopathogenic fungi in a moss, Physcomitrella patens

    KAUST Repository

    Decker, Eva L.; Alder, Adrian; Hunn, Stefan; Ferguson, Jenny; Lehtonen, Mikko T.; Scheler, Bjoern; Kerres, Klaus L.; Wiedemann, Gertrud; Safavi-Rizi, Vajiheh; Nordzieke, Steffen; Balakrishna, Aparna; Baz, Lina Abdulkareem Ali; Avalos, Javier; Valkonen, Jari P. T.; Reski, Ralf; Al-Babili, Salim

    2017-01-01

    . Wild-type (WT) exudates induced seed germination in Orobanche ramosa. This activity was increased upon phosphate starvation and abolished in exudates of both mutants. Furthermore, both mutants showed increased susceptibility to phytopathogenic fungi

  19. Investigating the Tolerance of Tomato (Lycopersicon esculentum Cultivars to Broomrape (Orobanche aegyptiaca pers in Khorassan Razavi

    Directory of Open Access Journals (Sweden)

    M. Zafarian,

    2014-03-01

    Full Text Available To investigate the tolerance of tomato cultivars to Egyptian broomrape (Orobanche aegyptiaca pers., an experiment was conducted in a randomized complete block design with 11 treatments and 3 replications in mazrae Nemoune Astan Quds Razavi in Mashhad, Iran, 2012. Treatment were 11 varieties (Peto early CH, Sterling (Karon, Khorram, Petorak, DNP 3005, PS 6515, SPEEDY, IDEN, VADI STAR, FIRINZEH and DNP 3001 which were transplanted in the field along with broomrape. Sampling was done at two stages: 1- after appearance and establishment of broomrape on tomato root where the dry weight, stem number and node numbers of broomrape on tomato root and tomato dry weight were measured and 2- at the end of growing season where tomato fruit weight and its yield were determined. Result indicated that Sterling and Khorram cultivars did have the least broomrape dry weight, stem number and node numbers of broomrape on tomato root and while produced highest plant dry weight, fruit and yield as compared to the other cultivars. Thus, may be considered as tolerant cultivars. Petorak and DNP 3001 on the other hand, presented the most broomrape dry weight, stem number and node number on tomato root. However, Petorak, Peto early CH and FIRINZEH cultivars produced the least plant weight, fruit and yield and thus, they can be called the sensitive cultivars. DNP 3001 being highly attacked by broomrape produced increased fruit yield and therefore compensated its ill effects.

  20. Selection of housekeeping genes for normalization by real-time RT-PCR: analysis of Or-MYB1 gene expression in Orobanche ramosa development.

    Science.gov (United States)

    González-Verdejo, C I; Die, J V; Nadal, S; Jiménez-Marín, A; Moreno, M T; Román, B

    2008-08-15

    Real-time PCR has become the method of choice for accurate and in-depth expression studies of candidate genes. To avoid bias, real-time PCR is referred to one or several internal control genes that should not fluctuate among treatments. A need for reference genes in the parasitic plant Orobanche ramosa has emerged, and the studies in this area have not yet been evaluated. In this study, the genes 18S rRNA, Or-act1, Or-tub1, and Or-ubq1 were compared in terms of expression stability using the BestKeeper software program. Among the four common endogenous control genes, Or-act1 and Or-ubq1 were the most stable in O. ramosa samples. In parallel, a study was carried out studying the expression of the transcription factor Or-MYB1 that seemed to be implicated during preinfection stages. The normalization strategy presented here is a prerequisite to accurate real-time PCR expression profiling that, among other things, opens up the possibility of studying messenger RNA levels of low-copy-number-like transcription factors.

  1. New localities of Orobanche bartlingii Griseb. in the Silesian-Cracow Upland as a result of the spread of Libanotis pyrenaica (L. Bourg. due to the changes in land use

    Directory of Open Access Journals (Sweden)

    Babczyńska-Sendek Beata

    2015-09-01

    Full Text Available Human activity is a factor strongly influencing the current state of vegetation. The abandonment of traditional land use enables uncontrolled secondary succession. Libanotis pyrenaica, a host plant for Orobanche bartlingii, is a great example of species that spread as a result of this process, especially in the area of the Silesian-Cracow Upland. The aim of this study is to show that the expansion of L. pyrenaica caused by changes in land use promotes spreading of O. bartlingii - a species rare in Poland and Europe. During the field research conducted in the last decade, further localities of O. bartlingii were found. The gathered data were summarized to supplement the known distribution of the species and to present floristic and ecological characteristics of the phytocenoses with the participation of L. pyrenaica and O. bartlingii.

  2. Topical application of a cleanser containing extracts of Diospyros kaki folium, Polygonum cuspidatum and Castanea crenata var. dulcis reduces skin oil content and pore size in human skin.

    Science.gov (United States)

    Lee, Bo Mi; An, Sungkwan; Kim, Soo-Yeon; Han, Hyun Joo; Jeong, Yu-Jin; Lee, Kyoung-Rok; Roh, Nam Kyung; Ahn, Kyu Joong; An, In-Sook; Cha, Hwa Jun

    2015-05-01

    The effects of skin pores on skin topographic features can be reduced by decreasing excessive production and accumulation of sebum and elimination of comedones. Therefore, a cosmetic cleanser that regulates sebum homeostasis is required. In the present study, the effects of a cosmetic cleanser that contained Diospyros kaki folium, Polygonum cuspidatum and Castanea crenata var. dulcis (DPC) was examined on the removal of sebum and on skin pore size. Healthy volunteers (n=23) aged 20-50 years were asked to apply the test materials to the face. Skin oil content, pore size, pore number and extracted sebum surface area were measured using various measurement methods. All the measurements were performed at pre- and post-application of the test materials. When the cosmetic cleanser containing DPC was applied to the skin, the oil content decreased by 77.3%, from 6.19 to 1.40. The number of skin pores decreased by 24.83%, from 125.39 to 94.23. Skin pore size decreased from 0.07 to 0.02 µm 3 (71.43% decrease). The amount of extracted sebum increased by 335% when the DPC cleanser was used. Compared to the control cleanser, skin oil content was significantly decreased when the cleanser that contained DPC was used. The cleanser containing DPC also decreased pore size and number. Finally, the DPC cleanser easily removed solidified sebum from the skin.

  3. Orobanchaceae in the

    Directory of Open Access Journals (Sweden)

    Foley, Michael J.Y.

    2000-12-01

    Full Text Available Two new Orobanche taxa are described: O. austrohispanica MJ.Y. Foley, and O. crinita Viv. var. occidentalis MJ.Y. Foley. Thirty-one species or subspecies of Orobanche and one species of Cistanche have been confirmed as being present within the Flora iberica área but some others previously recorded appear to have been so erroneously. In addition, Lathraea phelypaea L. {Cistanche phelypaea (L. Cout.] and nine species of Orobanche (O. caryophyllacea Sm., O. cernua Loefl., O. elatior Sutton, O. gracilis Sm., O. ramose L., O. reticulate Wallr., O. rosmarina Beck, O. schultzii Mutel y O. variegata Wallr. are typified.Se describen una especie y una variedad nuevas de Orobanche: O. austrohispanica M J.Y. Foley y O. crinita Viv. var. occidentalis MJ.Y. Foley. Del estudio del material de herbario disponible se concluye que las Orobanchaceae están representadas en el área de Flora iberica por una especie de Cistanche y 31 de Orobanche. Se discuten las citas de varias especies de ambos géneros que han de ser consideradas erróneas o dudosas. Además se tipifican Lathraea phelypaea L. [Cistanche phelypaea (L. Cout.] y nueve especies de Orobanche (O. caryophyllacea Sm., O. cernua Loefl., O. elatior Sutton, O. gracilis Sm., O. ramose L., O. reticulate Wallr., O. rosmarina Beck, O. schultzii Mutel y O. variegate Wallr..

  4. OaMAX2 of Orobanche aegyptiaca and Arabidopsis AtMAX2 share conserved functions in both development and drought responses.

    Science.gov (United States)

    Li, Weiqiang; Nguyen, Kien Huu; Watanabe, Yasuko; Yamaguchi, Shinjiro; Tran, Lam-Son Phan

    2016-09-16

    Previous studies in Arabidopsis reported that the MAX2 (more axillary growth 2) gene is a component of the strigolactone (SL) signaling pathway, which regulates a wide range of biological processes, from plant growth and development to environmental stress responses. Orobanche aegyptiaca is a harmful parasitic plant for many economically important crops. Seed germination of O. aegyptiaca is very sensitive to SLs, suggesting that O. aegyptiaca may contain components of the SL signaling pathway. To investigate this hypothesis, we identified and cloned a MAX2 ortholog from O. aegyptiaca for complementation analyses using the Arabidopsis Atmax2 mutant. The so-called OaMAX2 gene could rescue phenotypes of the Atmax2 mutant in various tested developmental aspects, including seed germination, shoot branching, leaf senescence and growth and development of hypocotyl, root hair, primary root and lateral root. More importantly, OaMAX2 could enhance the drought tolerance of Atmax2 mutant, suggesting its ability to restore the drought-tolerant phenotype of mutant plants defected in AtMAX2 function. Thus, this study provides genetic evidence that the functions of the MAX2 orthologs, and perhaps the MAX2 signaling pathways, are conserved in parasitic and non-parasitic plants. Furthermore, the results of our study enable us to develop a strategy to fight against parasitic plants by suppressing the MAX signaling, which ultimately leads to enhanced productivity of crop plants. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. The Role of Endogenous Strigolactones and Their Interaction with ABA during the Infection Process of the Parasitic Weed Phelipanche ramosa in Tomato Plants

    Czech Academy of Sciences Publication Activity Database

    Cheng, X.; Floková, Kristýna; Bouwmeester, H.; Ruyter-Spira, C.

    2017-01-01

    Roč. 8, MAR 24 (2017), č. článku 392. ISSN 1664-462X Institutional support: RVO:61389030 Keywords : suppression subtractive hybridization * hemiparasite rhinanthus-minor * putative defense genes * box protein max2 * abscisic-acid * striga-hermonthica * arabidopsis-thaliana * orobanche-aegyptiaca * medicago-truncatula * expression analysis * root parasitic plant * strigolactone * abscisic acid * post-attachment resistance * plant architecture Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 4.298, year: 2016

  6. Micromorphology of flowers and the structure of floral nectaries in Orobanche alsatica Kirschl.

    Directory of Open Access Journals (Sweden)

    Aneta Sulborska

    2014-04-01

    Full Text Available Orobanche alsatica Kirschl. is a very rare perennial plant included in the Polish Red Data Book. The hosts of this European-West Asian parasite are representatives of the family Apiaceae, primarily from the genera Peucedanum and Seseli. The species prefers alkaline substrates and sun-exposed slopes and hills. In Poland, it occurs most frequently in xerothermic grasslands and xerothermic fringe. The morphology of O. alsatica flowers, with special emphasis on the structure of the nectaries, was studied using light microscopy and scanning electron microscopy (SEM. The analysed plants originated from the Lublin Upland. The flowers of the species are characterised by the presence of a double perianth. The sepals are richly glandular, free; the outer sepals are dark red and the inner ones are yellow-green. Fused petals (5 form a bilabiate, dirty yellow corolla with dark red secretory trichomes on the abaxial surface. The stamens (4 with long, white S-shaped filaments are attached at the base to the corolla. There are glandular and non-glandular trichomes at the basal part of the filaments. Brown, oval anthers are characterised by the presence of a beak-like apex. The upper pistil is composed of an oval ovary and an arched style with a bipartite, fleshy, yellow stigma bearing numerous papillae. The O. alsatica nectary is formed by the basal part of the ovary at the corolla tube base. The secretory gland is intensively yellow and asymmetrical – on one side of the ovary it is higher and forms different height and size 4-5 protuberances, while on the other side it is very low. Nectar is secreted through modified stomata located primarily in the central part of the nectary. Stomatal cells are surrounded by 6-8 other epidermal cells and are located below these. The stomata are very regularly (linearly arranged forming a ring across the apical part of the protuberances. The stomata function asynchronously, as evidenced by the presence of both open and

  7. Morphology and histochemistry of glandular trichomes of Orobanche alba Stephan ex Willd

    Directory of Open Access Journals (Sweden)

    Aneta Sulborska

    2014-04-01

    Full Text Available Orobanche alba Stephan ex Willd is an achlorophyllous root parasite rare in Poland. It prefers dry and sunny slopes, xerothermic grasslands and pastures, mountain pastures, light scrubs, and rock fissures and ledges. The hosts of O. alba include Thymus polytrichus A. ern. ex Borbás, Clinopodium vulgare L. and Origanum vulgare L. The tick and fleshy 10-70 cm high stem in this species bears an inflorescence composed of zygomorphic, white or yellow “spotted” flowers covered by purple glandular trichomes. Glandular trichomes of this type are also borne on other parts of the plant, i.e. on the stem, scaly leaves, sepals, filaments, and the style. The secondary metabolites secreted by the glandular trichomes are related to defense of plants against the attack of herbivores and pathogens or act as attractants to pollinators or for fruit dispersal. The micromorphology and histochemistry of the glandular trichomes in O. alba were examined using scanning electron and light microscopes. In order to determine the type of secondary metabolites produced by the trichomes, the flowing histochemical assays were used: Sudan III and neutral red for detection of lipophilic compounds, IKI for detection of starch, and FeCl3 for detection of phenolic compounds. The peltate glandular trichomes of O. alba were characterised by a varied length (0.15‑0.48 mm and different activity phases. The trichome was composed of one larger basal epidermal cell, 1-3 hyaline stalk cells with a striated cuticle, a neck cell with a smooth cuticle on the surface, and a globose head formed of 8-18 secretory cells arranged in a circle. Many stalk cells of the trichomes, particularly those located on the corolla, contained anthocyanins, which give the trichomes dark carmine colour. In turn, the colour of the heads was dependent on trichome age: the heads were brown in older trichomes and yellow in younger hairs. Secretion was produced by both young and older trichomes. It penetrated

  8. Root parasitic plant Orobanche aegyptiaca and shoot parasitic plant Cuscuta australis obtained Brassicaceae-specific strictosidine synthase-like genes by horizontal gene transfer.

    Science.gov (United States)

    Zhang, Dale; Qi, Jinfeng; Yue, Jipei; Huang, Jinling; Sun, Ting; Li, Suoping; Wen, Jian-Fan; Hettenhausen, Christian; Wu, Jinsong; Wang, Lei; Zhuang, Huifu; Wu, Jianqiang; Sun, Guiling

    2014-01-13

    Besides gene duplication and de novo gene generation, horizontal gene transfer (HGT) is another important way of acquiring new genes. HGT may endow the recipients with novel phenotypic traits that are important for species evolution and adaption to new ecological niches. Parasitic systems expectedly allow the occurrence of HGT at relatively high frequencies due to their long-term physical contact. In plants, a number of HGT events have been reported between the organelles of parasites and the hosts, but HGT between host and parasite nuclear genomes has rarely been found. A thorough transcriptome screening revealed that a strictosidine synthase-like (SSL) gene in the root parasitic plant Orobanche aegyptiaca and the shoot parasitic plant Cuscuta australis showed much higher sequence similarities with those in Brassicaceae than with those in their close relatives, suggesting independent gene horizontal transfer events from Brassicaceae to these parasites. These findings were strongly supported by phylogenetic analysis and their identical unique amino acid residues and deletions. Intriguingly, the nucleus-located SSL genes in Brassicaceae belonged to a new member of SSL gene family, which were originated from gene duplication. The presence of introns indicated that the transfer occurred directly by DNA integration in both parasites. Furthermore, positive selection was detected in the foreign SSL gene in O. aegyptiaca but not in C. australis. The expression of the foreign SSL genes in these two parasitic plants was detected in multiple development stages and tissues, and the foreign SSL gene was induced after wounding treatment in C. australis stems. These data imply that the foreign genes may still retain certain functions in the recipient species. Our study strongly supports that parasitic plants can gain novel nuclear genes from distantly related host species by HGT and the foreign genes may execute certain functions in the new hosts.

  9. Planteose as a storage carbohydrate required for early stage of germination of Orobanche minor and its metabolism as a possible target for selective control

    Science.gov (United States)

    Wakabayashi, Takatoshi; Joseph, Benesh; Yasumoto, Shuhei; Akashi, Tomoyoshi; Aoki, Toshio; Harada, Kazuo; Muranaka, Satoru; Bamba, Takeshi; Fukusaki, Eiichiro; Takeuchi, Yasutomo; Yoneyama, Koichi; Muranaka, Toshiya; Sugimoto, Yukihiro; Okazawa, Atsushi

    2015-01-01

    Root parasitic weeds in Orobanchaceae cause serious damage to worldwide agriculture. Germination of the parasites requires host-derived germination stimulants, such as strigolactones, as indicators of host roots within reach of the parasite’s radicles. This unique germination process was focused on to identify metabolic pathways required for germination, and to design a selective control strategy. A metabolomic analysis of germinating seeds of clover broomrape, Orobanche minor, was conducted to identify its distinctive metabolites. Consequently, a galactosyl-sucrose trisaccharide, planteose (α-d-galactopyranosyl-(1→6)-β-d-fructofuranosyl-(2→1)-α-d-glucopyranoside), was identified as a metabolite that decreased promptly after reception of the germination stimulant. To investigate the importance of planteose metabolism, the effects of several glycosidase inhibitors were examined, and nojirimycin bisulfite (NJ) was found to alter the sugar metabolism and to selectively inhibit the germination of O. minor. Planteose consumption was similar in NJ-treated seeds and non-treated germinating seeds; however, NJ-treated seeds showed lower consumption of sucrose, a possible intermediate of planteose metabolism, resulting in significantly less glucose and fructose. This inhibitory effect was recovered by adding glucose. These results suggest that planteose is a storage carbohydrate required for early stage of germination of O. minor, and NJ inhibits germination by blocking the supply of essential glucose from planteose and sucrose. Additionally, NJ selectively inhibited radicle elongation of germinated seeds of Orobanchaceae plants (Striga hermonthica and Phtheirospermum japonicum). Thus, NJ will be a promising tool to develop specific herbicides to the parasites, especially broomrapes, and to improve our understanding of the molecular mechanisms of this unique germination. PMID:25821071

  10. Planteose as a storage carbohydrate required for early stage of germination of Orobanche minor and its metabolism as a possible target for selective control.

    Science.gov (United States)

    Wakabayashi, Takatoshi; Joseph, Benesh; Yasumoto, Shuhei; Akashi, Tomoyoshi; Aoki, Toshio; Harada, Kazuo; Muranaka, Satoru; Bamba, Takeshi; Fukusaki, Eiichiro; Takeuchi, Yasutomo; Yoneyama, Koichi; Muranaka, Toshiya; Sugimoto, Yukihiro; Okazawa, Atsushi

    2015-06-01

    Root parasitic weeds in Orobanchaceae cause serious damage to worldwide agriculture. Germination of the parasites requires host-derived germination stimulants, such as strigolactones, as indicators of host roots within reach of the parasite's radicles. This unique germination process was focused on to identify metabolic pathways required for germination, and to design a selective control strategy. A metabolomic analysis of germinating seeds of clover broomrape, Orobanche minor, was conducted to identify its distinctive metabolites. Consequently, a galactosyl-sucrose trisaccharide, planteose (α-d-galactopyranosyl-(1→6)-β-d-fructofuranosyl-(2→1)-α-d-glucopyranoside), was identified as a metabolite that decreased promptly after reception of the germination stimulant. To investigate the importance of planteose metabolism, the effects of several glycosidase inhibitors were examined, and nojirimycin bisulfite (NJ) was found to alter the sugar metabolism and to selectively inhibit the germination of O. minor. Planteose consumption was similar in NJ-treated seeds and non-treated germinating seeds; however, NJ-treated seeds showed lower consumption of sucrose, a possible intermediate of planteose metabolism, resulting in significantly less glucose and fructose. This inhibitory effect was recovered by adding glucose. These results suggest that planteose is a storage carbohydrate required for early stage of germination of O. minor, and NJ inhibits germination by blocking the supply of essential glucose from planteose and sucrose. Additionally, NJ selectively inhibited radicle elongation of germinated seeds of Orobanchaceae plants (Striga hermonthica and Phtheirospermum japonicum). Thus, NJ will be a promising tool to develop specific herbicides to the parasites, especially broomrapes, and to improve our understanding of the molecular mechanisms of this unique germination. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental

  11. Faba Greens, Globe Artichoke’s Offshoots, Crenate Broomrape and Summer Squash Greens: Unconventional Vegetables of Puglia (Southern Italy With Good Quality Traits

    Directory of Open Access Journals (Sweden)

    Massimiliano Renna

    2018-03-01

    Full Text Available Globe artichoke (Cynara cardunculus L. subsp. [L.] scolymus Hayek, summer squash (Cucurbita pepo L. and faba bean (Vicia faba L. are widely cultivated for their immature inflorescences, fruits and seeds, respectively. Nevertheless, in some areas of Puglia (Southern Italy, other organs of these species are traditionally used as vegetables, instead of being considered as by-products. Offshoots (so-called cardoni or carducci of globe artichoke, produced during the vegetative growing cycle and removed by common cultural procedures, are used like to the cultivated cardoons (C. cardunculus L. var. altilis DC. The stems, petioles, flowers and smaller leaves of summer squash are used as greens (so-called cime di zucchini, like other leafy vegetables such as chicory (Cichorium intybus L. and Swiss chard (Beta vulgaris L.. Also the plant apex of faba bean, about 5–10 cm long, obtained from the green pruning, are used as greens (so-called cime di fava like spinach leaves. Moreover, crenate broomrape (Orobanche crenata Forssk., a root parasite plant that produces devastating effects on many crops (mostly legumes, is used like asparagus (Asparagus officinalis L. to prepare several traditional dishes. In this study ethnobotanical surveys and quality assessment of these unconventional vegetables were performed. For their content of fiber, offshoots of globe artichokes can be considered a useful food to bowel. Summer squash greens could be recommended as a vegetable to use especially in the case of hypoglycemic diets considering both content and composition of their carbohydrates. For their low content of nitrate, faba greens could be recommended as a substitute of nitrate-rich leafy vegetables. Crenate broomrape shows a high antioxidant activity and may be considered as a very nutritious agri-food product. Overall, the results of the present study indicate that offshoots of globe artichoke, summer squash greens, faba greens and crenate broomrape have good

  12. Multiple, Distinct Intercontinental Lineages but Isolation of Australian Populations in a Cosmopolitan Lichen-Forming Fungal Taxon, Psora decipiens (Psoraceae, Ascomycota

    Directory of Open Access Journals (Sweden)

    Steven D. Leavitt

    2018-02-01

    Full Text Available Multiple drivers shape the spatial distribution of species, including dispersal capacity, niche incumbency, climate variability, orographic barriers, and plate tectonics. However, biogeographic patterns of fungi commonly do not fit conventional expectations based on studies of animals and plants. Fungi, in general, are known to occur across exceedingly broad, intercontinental distributions, including some important components of biological soil crust communities (BSCs. However, molecular data often reveal unexpected biogeographic patterns in lichenized fungal species that are assumed to have cosmopolitan distributions. The lichen-forming fungal species Psora decipiens is found on all continents, except Antarctica and occurs in BSCs across diverse habitats, ranging from hot, arid deserts to alpine habitats. In order to better understand factors that shape population structure in cosmopolitan lichen-forming fungal species, we investigated biogeographic patterns in the cosmopolitan taxon P. decipiens, along with the closely related taxa P. crenata and P. saviczii. We generated a multi-locus sequence dataset based on a worldwide sampling of these taxa in order to reconstruct evolutionary relationships and explore phylogeographic patterns. Both P. crenata and P. decipiens were not recovered as monophyletic; and P. saviczii specimens were recovered as a monophyletic clade closely related to a number of lineages comprised of specimens representing P. decipiens. Striking phylogeographic patterns were observed for P. crenata, with populations from distinct geographic regions belonging to well-separated, monophyletic lineages. South African populations of P. crenata were further divided into well-supported sub-clades. While well-supported phylogenetic substructure was also observed for the nominal taxon P. decipiens, nearly all lineages were comprised of specimens collected from intercontinental populations. However, all Australian specimens representing

  13. Use of microsatellite markers in an American beech (Fagus grandifolia) population and paternity testing

    Science.gov (United States)

    Jennifer Koch; Dave Carey; M.E. Mason

    2010-01-01

    Cross-species amplification of six microsatellite markers from European beech (Fagus sylvatica Linn) and nine markers from Japanese beech (Fagus crenata Blume) was tested in American beech (Fagus grandifolia Ehrh.). Three microsatellites from each species were successfully adapted for use in American beech...

  14. Fluorescence Imaging in the Red and Far-Red Region during Growth of Sunflower Plantlets. Diagnosis of the Early Infection by the Parasite Orobanche cumana

    Science.gov (United States)

    Ortiz-Bustos, Carmen M.; Pérez-Bueno, María L.; Barón, Matilde; Molinero-Ruiz, Leire

    2016-01-01

    Broomrape, caused by the root holoparasite Orobanche cumana, is the main biotic constraint to sunflower oil production worldwide. By the time broomrape emerges, most of the metabolic imbalance has been produced by O. cumana to sunflower plants. UV-induced multicolor fluorescence imaging (MCFI) provides information on the fluorescence emitted by chlorophyll (Chl) a of plants in the spectral bands with peaks near 680 nm (red, F680) and 740 nm (far-red, F740). In this work MCFI was extensively applied to sunflowers, either healthy or parasitized plants, for the first time. The distribution of red and far-red fluorescence was analyzed in healthy sunflower grown in pots under greenhouse conditions. Fluorescence patterns were analyzed across the leaf surface and throughout the plant by comparing the first four leaf pairs (LPs) between the second and fifth week of growth. Similar fluorescence patterns, with a delay of 3 or 4 days between them, were obtained for LPs of healthy sunflower, showing that red and far-red fluorescence varied with the developmental stage of the leaf. The use of F680 and F740 as indicators of sunflower infection by O. cumana during underground development stages of the parasite was also evaluated under similar experimental conditions. Early increases in F680 and F740 as well as decreases in F680/F740 were detected upon infection by O. cumana. Significant differences between inoculated and control plants depended on the LP that was considered at any time. Measurements of Chl contents and final total Chl content supported the results of MCFI, but they were less sensitive in differentiating healthy from inoculated plants. Sunflower infection was confirmed by the presence of broomrape nodules in the roots at the end of the experiment. The potential of MCFI in the red and far-red region for an early detection of O. cumana infection in sunflower was revealed. This technique might have a particular interest for early phenotyping in sunflower breeding

  15. In Vitro Antimicrobial Activity Of Crude Extracts From Plants ...

    African Journals Online (AJOL)

    Extracts from the leaves of Bryophyllum pinnatum and Kalanchoe crenata were screened for their antimicrobial activities. Solvents used included water, methanol, and local solvents such as palmwine, local gin (Seaman's Schnapps 40% alcoholic drink,) and “omi ekan-ogi” (Sour water from 3 days fermented milled maize).

  16. Biodegradation of lignin by Shiitake Lentinus edodes (berk. ) sing

    Energy Technology Data Exchange (ETDEWEB)

    Oki, T.; Watanabe, H.; Ishikawa, H.

    1981-01-01

    Each strain of L. edodes destroyed all of the structural components of wood (Fagus crenata) at almost the same rate during the loss of approximately 30% of the total weight of wood. The activities of the extracellular enzymes, i.e. peroxidase, laccase, and polyphenol oxidase, in the wood powder and lignin-containing cultures increased during the early period of mycelial growth, and then declined rapidly, while the activity of Beta-glucosidase increased gradually throughout the growth period. Functional group analysis, nitrobenzene oxidation, and spectroscopic characterization showed that dioxane lignin from F. crenata degraded by L. edodes or in crude enzyme solution isolated from wood-containing culture had a higher content of carboxyl groups than the sound dioxane lignin, whereas the content of methoxyl group was lower in the degraded dioxane lignin than in sound dioxane lignin. The building units of dioxane lignin, which yield aromatic aldehydes on nitrobenzene oxidation, were attacked preferentially by L. edodes under the above conditions.

  17. Enhanced Host-Parasite Resistance Based on Down-Regulation of Phelipanche aegyptiaca Target Genes Is Likely by Mobile Small RNA

    Directory of Open Access Journals (Sweden)

    Neeraj K. Dubey

    2017-09-01

    Full Text Available RNA silencing refers to diverse mechanisms that control gene expression at transcriptional and post-transcriptional levels which can also be used in parasitic pathogens of plants that Broomrapes (Orobanche/Phelipanche spp. are holoparasitic plants that subsist on the roots of a variety of agricultural crops and cause severe negative effects on the yield and yield quality of those crops. Effective methods for controlling parasitic weeds are scarce, with only a few known cases of genetic resistance. In the current study, we suggest an improved strategy for the control of parasitic weeds based on trans-specific gene-silencing of three parasite genes at once. We used two strategies to express dsRNA containing selected sequences of three Phelipanche aegyptiaca genes PaACS, PaM6PR, and PaPrx1 (pma: transient expression using Tobacco rattle virus (TRV:pma as a virus-induced gene-silencing vector and stable expression in transgenic tomato Solanum lycopersicum (Mill. plants harboring a hairpin construct (pBINPLUS35:pma. siRNA-mediated transgene-silencing (20–24 nt was detected in the host plants. Our results demonstrate that the quantities of PaACS and PaM6PR transcripts from P. aegyptiaca tubercles grown on transgenic tomato or on TRV-infected Nicotiana benthamiana plants were significantly reduced. However, only partial reductions in the quantity of PaPrx1 transcripts were observed in the parasite tubercles grown on tomato and on N. benthamiana plants. Concomitant with the suppression of the target genes, there were significant decreases in the number and weight of the parasite tubercles that grew on the host plants, in both the transient and the stable experimental systems. The results of the work carried out using both strategies point to the movement of mobile exogenous siRNA from the host to the parasite, leading to the impaired expression of essential parasite target genes.

  18. EXPRESSION OF SOME ANTIOXIDANT GENES IN SUNFLOWER INFECTED WITH BROOMRAPE

    Directory of Open Access Journals (Sweden)

    Tatiana Shestakova

    2015-11-01

    Full Text Available Expression levels of ROS-scavenging genes (MnSODI, APX3 and AOX1A in leaves (R5 stage; 90 days after sowing of seven sunflower genotypes infected with three Orobanche cumana Wallr. populations were assayed in plants with/without broomrape aerial shoots and control group. Five lines were highly susceptible to all three populations. MS-2161A was resistant and MS-2039A was tolerant to broomrape populations. The expression of studied genes was much more altered in highly susceptible genotypes than in those resistant. Significant differences in number of cases of ROS-scavenging genes with modified transcriptional activity in infected and non-symptomatic plants were not ascertained. The transcriptional activity of MnSODI, APX3 and AOX1A genes was weakly influenced by infection with broomrape (67 % cases or was down-regulated (24 % cases. Some up-regulation cases (9 % for MnSODI (MS-2039 and AOX1A gene (MS-2067 were revealed. AOX1A was the most responsive gene, especially when infection was produced by population from Anenii Noi. 

  19. THE BIOLOGICAL CYCLE OF SUNFLOWER BROOMRAPE

    Directory of Open Access Journals (Sweden)

    DUCA Maria

    2013-12-01

    Full Text Available Orobanchaceae is a dicot family, which consists of annual and perennial plants distributing from tropical to subarctic regions, predominately in temperate regions. Broomrape (Orobanche cumana Wallr. = Orobanche cernua Loefl. is a parasitic angiosperm that has been causing a great deal of damage to sunflower production in many countries, including Republic of Moldova. This parasitic angiosperm depends entirely on the host for its supply of water and nutrients. A thorough understanding of its biology, including detailed knowledge of the specific mechanisms of parasitism, is needed in order to develop novel control methods. Some main developmental steps are described for the root parasites: seed conditioning and germination, haustorium formation, penetration into host tissues, maturation of the parasite plant, and seed production. All these stages were studied in artificial and natural conditions.

  20. Anti-dyslipidemic and Antioxidant Potentials of Methanol Extract of ...

    African Journals Online (AJOL)

    Purpose: The activity of the methanol extract of the whole plant of Kalanchoe crenata (MEKC) was studied for the treatment of diabetes-induced nephropathy in rats. Methods: Five-day old Wistar rats received a single intraperitoneal streptozotocin injection (90 ìg/kg body weight) to induce diabetes. Kidney disease onset in ...

  1. Tree Branching: Leonardo da Vinci's Rule versus Biomechanical Models

    Science.gov (United States)

    Minamino, Ryoko; Tateno, Masaki

    2014-01-01

    This study examined Leonardo da Vinci's rule (i.e., the sum of the cross-sectional area of all tree branches above a branching point at any height is equal to the cross-sectional area of the trunk or the branch immediately below the branching point) using simulations based on two biomechanical models: the uniform stress and elastic similarity models. Model calculations of the daughter/mother ratio (i.e., the ratio of the total cross-sectional area of the daughter branches to the cross-sectional area of the mother branch at the branching point) showed that both biomechanical models agreed with da Vinci's rule when the branching angles of daughter branches and the weights of lateral daughter branches were small; however, the models deviated from da Vinci's rule as the weights and/or the branching angles of lateral daughter branches increased. The calculated values of the two models were largely similar but differed in some ways. Field measurements of Fagus crenata and Abies homolepis also fit this trend, wherein models deviated from da Vinci's rule with increasing relative weights of lateral daughter branches. However, this deviation was small for a branching pattern in nature, where empirical measurements were taken under realistic measurement conditions; thus, da Vinci's rule did not critically contradict the biomechanical models in the case of real branching patterns, though the model calculations described the contradiction between da Vinci's rule and the biomechanical models. The field data for Fagus crenata fit the uniform stress model best, indicating that stress uniformity is the key constraint of branch morphology in Fagus crenata rather than elastic similarity or da Vinci's rule. On the other hand, mechanical constraints are not necessarily significant in the morphology of Abies homolepis branches, depending on the number of daughter branches. Rather, these branches were often in agreement with da Vinci's rule. PMID:24714065

  2. Tree branching: Leonardo da Vinci's rule versus biomechanical models.

    Science.gov (United States)

    Minamino, Ryoko; Tateno, Masaki

    2014-01-01

    This study examined Leonardo da Vinci's rule (i.e., the sum of the cross-sectional area of all tree branches above a branching point at any height is equal to the cross-sectional area of the trunk or the branch immediately below the branching point) using simulations based on two biomechanical models: the uniform stress and elastic similarity models. Model calculations of the daughter/mother ratio (i.e., the ratio of the total cross-sectional area of the daughter branches to the cross-sectional area of the mother branch at the branching point) showed that both biomechanical models agreed with da Vinci's rule when the branching angles of daughter branches and the weights of lateral daughter branches were small; however, the models deviated from da Vinci's rule as the weights and/or the branching angles of lateral daughter branches increased. The calculated values of the two models were largely similar but differed in some ways. Field measurements of Fagus crenata and Abies homolepis also fit this trend, wherein models deviated from da Vinci's rule with increasing relative weights of lateral daughter branches. However, this deviation was small for a branching pattern in nature, where empirical measurements were taken under realistic measurement conditions; thus, da Vinci's rule did not critically contradict the biomechanical models in the case of real branching patterns, though the model calculations described the contradiction between da Vinci's rule and the biomechanical models. The field data for Fagus crenata fit the uniform stress model best, indicating that stress uniformity is the key constraint of branch morphology in Fagus crenata rather than elastic similarity or da Vinci's rule. On the other hand, mechanical constraints are not necessarily significant in the morphology of Abies homolepis branches, depending on the number of daughter branches. Rather, these branches were often in agreement with da Vinci's rule.

  3. Gastropod growth and survival as bioindicators of stress associated with high nutrients in the intertidal of a shallow temperate estuary

    Science.gov (United States)

    Marsden, Islay D.; Baharuddin, Nursalwa

    2015-04-01

    The effects of multiple stressors on estuarine organisms are not well understood. Using cage experiments we measured the survival and growth of the pulmonate gastropod Amphibola crenata at five locations which differed contaminant levels. Water nutrients came from a nearby sewage treatment works and the sediment contained low levels of trace metals. Over 6 weeks of exposure, sediment surface chlorophyll levels varied amongst locations. The Chl a values were positively correlated with sediment N and P and trace metals As, Cd, Cu, Pb and Zn. Pulmonate survival depended on location, highest mortality was from a site close to the treatment plant and mortality rate of large individuals decreased significantly with distance away from it. For four locations, medium A. crenata had higher survival than small (juveniles) or adults. Growth rates of small individuals exceeded those for medium and large A. crenata. The mean length increment/week for medium gastropods ranged between 0.49 and 1.11 mm and was negatively correlated with the amount of Chl a in the surface sediment, suggesting the negative effects of eutrophication on gastropod growth. Growth rate of the pulmonate was not correlated with nutrient concentration or trace metal concentrations in the sediment. The dry weight condition index (CI) did not correlate with the growth rate, and for medium individuals, was unaffected by any of the environmental variables. The CI of small individuals was negatively affected by increasing water nutrient levels and the CI of large individuals negatively affected by increasing sediment nutrients and trace metal concentrations. The results from this study suggest that gastropod growth and survival could be used as tools to monitor the effects of changing nutrient levels and recovery from eutrophication within temperate estuaries.

  4. Optimization of epidemiological conditions to enhance the ...

    African Journals Online (AJOL)

    user

    2011-03-14

    Mar 14, 2011 ... Development of a PCR-based assay for the detection of Fusarium oxysporum strain FT2, a potential mycoherbicide of Orobanche ramosa. Biol. Control, 50: ... Effects of nitrogen availability and spore concentration on the ...

  5. Typologie spatiale de la végétation sahélienne en relation avec les ...

    African Journals Online (AJOL)

    hp

    0,0316. Tribulus terrestris L. 16,5. 0,0373. Très dégradé. Caralluma adscendens (Roxb.) Haw. 36,5. 0,0170. Acalypha crenata Hochst.ex A.Rich. 36,5. 0,0250. Tableau 4: Quantification comparative des variables par stade de dégradation. Variables de dégradation des glacis du bassin versant de. Gourouol. Peu dégradé.

  6. Compte rendu de la 18e Conférence Internationale sur le Tournesol : Mar del Plata & Balcarce (Argentine, 2012

    Directory of Open Access Journals (Sweden)

    Pilorgé Étienne

    2012-11-01

    Full Text Available The 18th International Sunflower Conference took place in Mar del Plata, Argentina, in February, 2012. The key-points and evolutions of sunflower research were presented, in the fields of agronomy, physiology, genetics and genomics, crop protection, quality and markets. Major evolutions can be observed concerning the sequencing of sunflower genome, announced to be complete by the end of 2012, but also concerning the use of models and the progress in the studies on the interactions between varieties genetic pattern, environment and crop management practices. In crop protection aspects, the evolutions of the major pathogens, downy mildew and Orobanche cumana, have been discussed, as well as the breeding efforts for genetic resistances, or the advances concerning the herbicides tolerant varieties. Evolutions in oil quality aspects have been exposed too, such as varieties enriched in stearic acid, or tocopherols, or with low contents in saturated fatty acids.

  7. [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.

  8. A resistência olha a resistência

    Directory of Open Access Journals (Sweden)

    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.

  9. Author Details

    African Journals Online (AJOL)

    Admasu, Assefa. Vol 22, No 2 (1999) - Articles Preliminary evaluation of Phytomyza orobanchia (Diptera: Agromyzidae) as a controller of Orobanche spp in Ethiopia Details PDF. ISSN: 2520–7997. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...

  10. Download this PDF file

    African Journals Online (AJOL)

    Orobanche control using synthetic germination stimulants. Weed Research 16: 223-227. Kim, S.K. and Adetimirin, V0. 1997. Striga hermonthica seed inoculum rate effects on maize hybrid tolerance and susceptibility expression. Crop Science 3711066-1071. M'Boob, 8.8. 1989. A regional program for. Striga control in West ...

  11. Mycoherbicidal potential of Alternaria alternata for management of ...

    African Journals Online (AJOL)

    hope&shola

    2010-12-06

    Dec 6, 2010 ... ramosaDevelopment of a PCR-based assay for the detection of. Fusarium oxysporum strain FT2, a potential mycoherbicide of. Orobanche ramosa. Biol. Control, 50: 78-84. Ellison CA, Barreto RW (2004). Prospects for the Management of. Invasive Alien Weeds Using Co-Evolved Fungal Pathogens: A Latin.

  12. 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...

  13. SINET: Ethiopian Journal of Science - Vol 22, No 2 (1999)

    African Journals Online (AJOL)

    ... evaluation of Phytomyza orobanchia (Diptera: Agromyzidae) as a controller of Orobanche spp in Ethiopia, EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. A E M Elzein, J Kroschel, Assefa Admasu, Masresha Fetene, 271-282. http://dx.doi.org/10.4314/sinet.v22i2.

  14. Author Details

    African Journals Online (AJOL)

    Details PDF · Vol 22, No 2 (1999) - Articles Vegetation under different tree species in Acacia woodland in the Rift Valley of Ethiopia Details PDF · Vol 22, No 2 (1999) - Articles Preliminary evaluation of Phytomyza orobanchia (Diptera: Agromyzidae) as a controller of Orobanche spp in Ethiopia Details PDF. ISSN: 2520–7997.

  15. 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.

  16. 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...

  17. Gene transfer from wild Helianthus to sunflower: topicalities and limits

    Directory of Open Access Journals (Sweden)

    Breton Catherine

    2010-03-01

    Full Text Available Sunflower (2n=17 belongs to the Helianthus genus (Asteraceae. Wild Helianthus species display morphological variation for branching and stem number, for architecture and seed size, and for resistance to abiotic and biotic stresses due to which they thrive in different environments in North America. The genus is divided into botanical sections, two for annual as sunflower, and two for perennial species as Jerusalem artichoke that produces rhizomes (tubers. We explain the difficulties and successes obtained by crossing sunflower with these species to improve the agronomic traits of the sunflower crop. It is easier to cross the annual species than the perennials’ with sunflower. Several traits such as Cytoplasmic male sterility and restorer Rf-PET1 genes, Downy mildew resistance, Phomopsis resistance, Sclerotinia resistance, Rust resistance, and Orobanche resistance have already been introduced from annual species into sunflower crop, but the complex genomic organization of these species compared to sunflower limits their important potential. Perennial species are much more diverse, and their genomes display 2n, 4n, or 6n chromosomes for n 17. The realities of inter-specific hybridization are relatively disappointing due to the introgression lines that have low oil and low seed yield. We report here several attempts to introgress agronomic traits from these species to sunflower, and we present as a case study, an introgressed progenies from H. mollis, a diploid species with sessile small leaves. We constructed a preliminary genetic map with AFLP markers in 21 BC1 plants, and we then showed that some progenies display 6 to 44% of introgression from H. mollis. Although this study is promising due to the novel compact architecture of the progenies, we cannot estimate the transferability from H. mollis to other perennial Helianthus to improve sunflower.

  18. 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.

  19. Beech cupules share endophytic fungi with leaves and twigs

    OpenAIRE

    Tateno, Osamu; Hirose, Dai; Osono, Takashi; Takeda, Hiroshi

    2015-01-01

    Endophytic mycobiota on leaves, twigs and cupules of Fagus crenata were investigated using a culture-dependent method over a growing season to test the hypothesis that endophytic fungi of cupule (a woody phyllome) share some components of the endophytic fungal assemblages with both leaves and twigs. A total of 14 fungal taxa were isolated, and the most frequent taxon was Phomopsis sp., followed by Xylaria sp., Ascochyta fagi and Geniculosporium sp. The compositions of fungal assemblages of le...

  20. 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

  1. 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

  2. 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.

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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....

  9. 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)

  10. 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)

  11. 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

  12. Phylogeny and character evolution of the fern genus Tectaria (Tectariaceae) in the Old World inferred from chloroplast DNA sequences.

    Science.gov (United States)

    Ding, Hui-Hui; Chao, Yi-Shan; Callado, John Rey; Dong, Shi-Yong

    2014-11-01

    In this study we provide a phylogeny for the pantropical fern genus Tectaria, with emphasis on the Old World species, based on sequences of five plastid regions (atpB, ndhF plus ndhF-trnL, rbcL, rps16-matK plus matK, and trnL-F). Maximum parsimony, maximum likelihood, and Bayesian inference are used to analyze 115 individuals, representing ca. 56 species of Tectaria s.l. and 36 species of ten related genera. The results strongly support the monophyly of Tectaria in a broad sense, in which Ctenitopsis, Hemigramma, Heterogonium, Psomiocarpa, Quercifilix, Stenosemia, and Tectaridium should be submerged. Such broadly circumscribed Tectaria is supported by the arising pattern of veinlets and the base chromosome number (x=40). Four primary clades are well resolved within Tectaria, one from the Neotropic (T. trifoliata clade) and three from the Old World (T. subtriphylla clade, Ctenitopsis clade, and T. crenata clade). Tectaria crenata clade is the largest one including six subclades. Of the genera previously recognized as tectarioid ferns, Ctenitis, Lastreopsis, and Pleocnemia, are confirmed to be members in Dryopteridaceae; while Pteridrys and Triplophyllum are supported in Tectariaceae. To infer morphological evolution, 13 commonly used characters are optimized on the resulting phylogenetic trees and in result, are all homoplastic in Tectaria. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Ecophysiological Traits of Leaves of Three Marsilea Species Distributed in Different Geographical Regions

    Directory of Open Access Journals (Sweden)

    Tai-Chung Wu

    2011-11-01

    Full Text Available Marsilea, an amphibian fern genus (containing ca. 80 species characterized by their unusual leaves and reproductive structures, is distributed over the five continents. To investigate the adaptation traits of three Marsilea species (M. crenata, M. quadrifolia, and M. schelpiana, distributed in different geographic regions, to terrestrial conditions, we compared morphological features, optical properties and photosynthetic performance of leaflets of the three species grown in terrestrial environment. The results showed that leaflets of the three species had significant differences in some of the ecophysiogical traits. Among the three species, M. quadrifolia (distributed in temperate region where receiving low precipitation had the highest trichome density on its leaflet surface and the highest water use efficiency, M. schelpiana (mainly in southern Africa where accepting high level of solar irradiance had the tallest petiole and the highest leaf dissection index, total stomatal pore area index, PSII electron transport rate and photosaturated photosynthetic rate, M. crenata (mainly in southeastern Asia region where receiving high precipitation and with high humidity had the lowest leaf dissection index and water use efficiency. Accordingly, leaf characteristics of the three Marsilea species reflect the climate pattern of their habitats. The results also suggest that water availability and light intensity are two of the important factors contributing to the geographic distribution of the three species.

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. New sunflower hybrids tolerant to tribenuron-methyl

    Directory of Open Access Journals (Sweden)

    Cvejić Sandra

    2016-01-01

    Full Text Available The creation of sunflower hybrids tolerant to tribenuron-methyl enabled the use of wider palette of herbicides to control effectively weeds during the growing season. Moreover, thanks to this tolerance, chemical control of broad-leaves weeds in sunflower, especially Cirsium arvense, is more efficient. The Institute of Field and Vegetable Crops offers four new hybrids tolerant to tribenuron-methyl: NS SUMO SUN, NS SUMO STAR, NS SUMO SjAj and NS SUMO SOL, released in 2016. Hybrids belong to early and medium-early maturity groups; have high yield potential and high oil content. They are adapted for cultivation in different environmental conditions. All hybrids are resistant to broomrape (Orobanche cumana Wallr races from A-E and have a high level of tolerance to Phomopsis, white rot (Sclerotinia sclorotiorum, rust (Puccinia helianthi and others. The paper presents the results of seed and oil yield from the official trials of the Department of variety registration within the Ministry of Agriculture and Environmental Protection of the Republic of Serbia.

  19. 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)

  20. 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 ...

  1. 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.

  2. 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

  3. 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.

  4. Testing the Hypothesis of Multiple Origins of Holoparasitism in Orobanchaceae: Phylogenetic Evidence from the Last Two Unplaced Holoparasitic Genera, Gleadovia and Phacellanthus

    Directory of Open Access Journals (Sweden)

    Weirui Fu

    2017-08-01

    Full Text Available Orobanchaceae is the largest family among the parasitic angiosperms. It comprises non-parasites, hemi- and holoparasites, making this family an ideal test case for studying the evolution of parasitism. Previous phylogenetic analyses showed that holoparasitism had arisen at least three times from the hemiparasitic taxa in Orobanchaceae. Until now, however, not all known genera of Orobanchaceae were investigated in detail. Among them, the unknown phylogenetic positions of the holoparasites Gleadovia and Phacellanthus are the key to testing how many times holoparasitism evolved. Here, we provide clear evidence for the first time that they are members of the tribe Orobancheae, using sequence data from multiple loci (nuclear genes ITS, PHYA, PHYB, and plastid genes rps2, matK. Gleadovia is an independent lineage whereas Phacellanthus should be merged into genus Orobanche section Orobanche. Our results unambiguously support the hypothesis that there are only three origins of holoparasitism in Orobanchaceae. Divergence dating reveals for the first time that the three origins of holoparasitism were not synchronous. Our findings suggest that holoparasitism can persist in specific clades for a long time and holoparasitism may evolve independently as an adaptation to certain hosts.

  5. 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...

  6. 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

  7. 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.

  8. Tomato strigolactones are derived from carotenoids and their biosynthesis is promoted by phosphate starvation

    OpenAIRE

    López-Ráez, Juan A.; Charnikhova, Tatsiana;; Gómez-Roldán,Victoria;; Matusova, Radoslava;; Kohlen, Wouter;; De Vos, Ric;; Verstappe, Francel;; Puech-Pages, Virginie;; Bécard, Guillaume;; Mulder, Patrick;; Bouwmeester, Harro;

    2008-01-01

    Strigolactones are rhizosphere signalling compounds that mediate host location in arbuscular mycorrhizal (AM) fungi and parasitic plants. Here, the regulation of the biosynthesis of strigolactones is studied in tomato (Solanum lycopersicum). * Strigolactone production under phosphate starvation, in the presence of the carotenoid biosynthesis inhibitor fluridone and in the abscisic acid (ABA) mutant notabilis were assessed using a germination bioassay with seeds of Orobanche ramosa; a hyphal b...

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. Suicidal germination for parasitic weed control.

    Science.gov (United States)

    Zwanenburg, Binne; Mwakaboko, Alinanuswe S; Kannan, Chinnaswamy

    2016-11-01

    Parasitic weeds of the genera Striga and Orobanche spp. cause severe yield losses in agriculture, especially in developing countries and the Mediterranean. Seeds of these weeds germinate by a chemical signal exuded by the roots of host plants. The radicle thus produced attaches to the root of the host plant, which can then supply nutrients to the parasite. There is an urgent need to control these weeds to ensure better agricultural production. The naturally occurring chemical signals are strigolactones (SLs), e.g. strigol and orobanchol. One option to control these weeds involves the use of SLs as suicidal germination agents, where germination takes place in the absence of a host. Owing to the lack of nutrients, the germinated seeds will die. The structure of natural SLs is too complex to allow multigram synthesis. Therefore, SL analogues are developed for this purpose. Examples are GR24 and Nijmegen-1. In this paper, the SL analogues Nijmegen-1 and Nijmegen-1 Me were applied in the field as suicidal germination agents. Both SL analogues were formulated using an appropriate EC-approved emulsifier (polyoxyethylene sorbitol hexaoleate) and applied to tobacco (Nicotiana tabacum L.) fields infested by Orobanche ramosa L. (hemp broomrape), following a strict protocol. Four out of 12 trials showed a reduction in broomrape of ≥95%, two trials were negative, two showed a moderate result, one was unclear and in three cases there was no Orobanche problem in the year of the trials. The trial plots were ca 2000 m 2 ; half of that area was treated with stimulant emulsion, the other half was not treated. The optimal amount of stimulant was 6.25 g ha -1 . A preconditioning prior to the treatment was a prerequisite for a successful trial. In conclusion, the suicidal germination approach to reducing O. ramosa in tobacco fields using formulated SL analogues was successful. Two other options for weed control are discussed: deactivation of stimulants prior to action and

  14. 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.

  15. 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...

  16. Combating Antibiotic Resistance

    Science.gov (United States)

    ... Bacteria Phasing Out Certain Antibiotic Use in Farm Animals FDA: Cutting-Edge Technology Sheds Light on Antibiotic Resistance For More Information Antibiotics and Antibiotic Resistance Antimicrobial Resistance Information for Consumers and Health Professionals CDC: ...

  17. 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. ...

  18. 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...

  19. 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...

  20. 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

  1. Measurement of Dynamic Resistance in Resistance Spot Welding

    DEFF Research Database (Denmark)

    Wu, Pei; Lu, J.; Zhang, Wenqi

    2007-01-01

    is influenced by inductive noise caused by the high welding current. In this study, the dynamic resistance is determined by measuring the voltage at primary side and current at secondary side. This increases the accuracy of measurement because of higher signal-noise ratio, and allows to apply to in-process......The conventional methods of determining the dynamic resistance were mostly done by measuring the voltage and current at secondary side of transformer in resistance welding machines, in which the measuring set-up normally interferes with the movement of electrode, and the measuring precision...

  2. 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

  3. Resistance patterns, prevalence, and predictors of fluoroquinolones resistance in multidrug resistant tuberculosis patients

    Directory of Open Access Journals (Sweden)

    Nafees Ahmad

    2016-01-01

    Conclusion: The high degree of drug resistance observed, particularly to fluoroquinolones, is alarming. We recommend the adoption of more restrictive policies to control non-prescription sale of fluoroquinolones, its rational use by physicians, and training doctors in both private and public–private mix sectors to prevent further increase in fluoroquinolones resistant Mycobacterium tuberculosis strains.

  4. 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

  5. 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.

  6. 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...

  7. Multidrug-resistant tuberculosis

    Directory of Open Access Journals (Sweden)

    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

  8. 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

  9. 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.

  10. 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.

  11. 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.)

  12. 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.

  13. Fitotossine di Inula viscosa per il controllo di piante parassite

    OpenAIRE

    Avolio, Fabiana

    2013-01-01

    Le piante parassite sono incapaci di sintetizzare dagli elementi minerali e nutritivi materiali sufficienti per la loro crescita e sopperiscono a questa deficienza fisiologica utilizzando le sostanze elaborate dalle piante ospiti, che di conseguenza manifestano generalmente una crescita ridotta. Le Orobanche, la Striga e la Cuscuta sono le piante parassite più diffuse nelle regioni del Mediterraneo e del continente africano interessando colture di rilevanza strategica. Diverse strategie...

  14. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... Animal & Veterinary Safety & Health Antimicrobial Resistance Animation of Antimicrobial Resistance Share Tweet Linkedin Pin it More sharing options ... of Animation of Antimicrobial Resistance More in Antimicrobial ... Antimicrobial Resistance Monitoring System About NARMS 2015 NARMS Integrated ...

  15. Antibiotic resistance reservoirs

    NARCIS (Netherlands)

    Versluis, Dennis

    2016-01-01

    One of the major threats to human health in the 21st century is the emergence of pathogenic bacteria that are resistant to multiple antibiotics, thereby limiting treatment options. An important route through which pathogens become resistant is via acquisition of resistance genes from

  16. 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...

  17. Analysis and modeling of resistive switching mechanisms oriented to resistive random-access memory

    International Nuclear Information System (INIS)

    Huang Da; Wu Jun-Jie; Tang Yu-Hua

    2013-01-01

    With the progress of the semiconductor industry, the resistive random-access memory (RAM) has drawn increasing attention. The discovery of the memristor has brought much attention to this study. Research has focused on the resistive switching characteristics of different materials and the analysis of resistive switching mechanisms. We discuss the resistive switching mechanisms of different materials in this paper and analyze the differences of those mechanisms from the view point of circuitry to establish their respective circuit models. Finally, simulations are presented. We give the prospect of using different materials in resistive RAM on account of their resistive switching mechanisms, which are applied to explain their resistive switchings

  18. Antimicrobial Resistance

    Science.gov (United States)

    ... least 10 countries (Australia, Austria, Canada, France, Japan, Norway, Slovenia, South Africa, Sweden and the United Kingdom ... plan Global report on surveillance Country situation analysis Policy to combat antimicrobial resistance More on antimicrobial resistance ...

  19. Antimicrobial Resistance

    Science.gov (United States)

    ... can prevent and manage antimicrobial resistance. It is collaborating with partners to strengthen the evidence base and ... on the global action plan. WHO has been leading multiple initiatives to address antimicrobial resistance: World Antibiotic ...

  20. 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

  1. 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.

  2. Resisting Mind Control.

    Science.gov (United States)

    Anderson, Susan M.; Zimbardo, Philip G.

    1980-01-01

    Provides conceptual analyses of mind control techniques along with practical advice on how to resist these techniques. The authors stress that effective mind control stems more from everyday social relations than from exotic technological gimmicks. Suggestions are given for resisting persuasion, resisting systems, and challenging the system.…

  3. 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.

  4. 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.

  5. 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...

  6. 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 ...

  7. Electrical resistivity measurements to predict abrasion resistance of ...

    Indian Academy of Sciences (India)

    WINTEC

    increasing expansion of highway and other construction works and decreasing natural aggregate resources in the world, the demand for crushed stone aggregates has in- creased from day-to-day. One of the important properties of rock aggregates is abrasion resistance. The abrasion resistance of aggregates is generally ...

  8. 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.

  9. [Resistance risk and resistance stability of Frankliniella occidentalis to imidacloprid, emamectin benzoate, and phoxim].

    Science.gov (United States)

    Wang, Sheng-Yin; Yu, Yi; Liu, Yong-Jie; Ma, Jing-Yu

    2012-12-01

    In order to effectively control the damage of Frankliniella occidentalis (Pergande), Phaseolus vuglaris was dipped with imidacloprid, phoxim, and emamectin benzoate, respectively to select the resistance populations of F. occidentalis from its susceptible population, and the resistance inheritance and resistance risk were analyzed with the resistance reality heredity. After 32, 32, and 24 generations' selection, the F. occidentalis populations obtained 13.8-fold, 29.4-fold and 39.0-fold resistance to imidacloprid, phoxim, and emamectin benzoate, respectively. The resistance reality heritability to imidacloprid, phoxim, and emamectin benzoate was 0.112, 0.166, and 0.259, respectively. The resistance development rate to emamectin benzoate was the fastest, followed by to phoxim, and to imidacloprid. The higher the resistance levels of the selected populations, the lower the differences between the larva and adult susceptibility to imidacloprid, phoxim, and emamectin benzoate. Stopping selection for 12 continuous generations, the resistance level of the selected resistance populations to imidacloprid, phoxim, and emamectin benzoate had definite decline, but it was difficult to regain the original susceptibility. F. occidentalis had a greater potential to gain high level resistance to imidacloprid, phoxim, and emamectin benzoate. Compared with the resistance of F. occidentalis to phoxim and emamectin benzoate, the resistance to imidacloprid increased slower and decreased faster, and thus, imidacloprid was more appropriate to control F. occidentalis in practice.

  10. Resistance Selection and Characterization of Chlorantraniliprole Resistance in Plutella xylostella (Lepidoptera: Plutellidae).

    Science.gov (United States)

    Liu, Xia; Wang, Hong-Yan; Ning, Yu-Bo; Qiao, Kang; Wang, Kai-Yun

    2015-08-01

    The diamondback moth, Plutella xylostella (L.), is considered one of the most damaging lepidopteran pests, and it has developed resistance to all conventional insecticide classes in the field. Chlorantraniliprole is the first commercial insecticide that belongs to the new chemical class of diamide insecticides. But, P. xylostella have already shown resistance to chlorantraniliprole in China. After 52 generations of selection with chlorantraniliprole, ∼48.17-fold resistance was observed. The resistant strain showed cross-resistance to flubendiamide (7.29-fold), abamectin (6.11-fold), and cyantraniliprole (3.31-fold). Quantitative real-time polymerase chain reaction analysis showed that the expression of the ryanodine receptor gene was higher in the resistant strain than that in the susceptible strain. Enzyme assays indicated that cytochrome P450 activity in the resistant strain was 4.26 times higher compared with the susceptible strain, whereas no difference was seen for glutathione-S-transferase and esterase. Moreover, the toxicity of chlorantraniliprole in the resistant strain could be synergized by piperonyl butoxide, but not by diethyl maleate, and S,S,S-tributyl phosphorothioate. These results can serve as an important base for guiding the use of insecticide in field and delaying the development of pests that are resistant to the insecticides. © 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.

  11. 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

  12. Cross-resistance, inheritance and biochemical mechanisms of imidacloprid resistance in B-biotype Bemisia tabaci.

    Science.gov (United States)

    Wang, Zhenyu; Yao, Mingde; Wu, Yidong

    2009-11-01

    The B-type Bemisia tabaci (Gennadius) has become established in many regions in China, and neonicotinoids are extensively used to control this pest. Imidacloprid resistance in a laboratory-selected strain of B-type B. tabaci was characterised in order to provide the basis for recommending resistance management tactics. The NJ-Imi strain of B-type B. tabaci was selected from the NJ strain with imidacloprid for 30 generations. The NJ-Imi strain exhibited 490-fold resistance to imidacloprid, high levels of cross-resistance to three other neonicotinoids, low levels of cross-resistance to monosultap, cartap and spinosad, but no cross-resistance to abamectin and cypermethrin. Imidacloprid resistance in the NJ-Imi strain was autosomal and semi-dominant. It is shown that enhanced detoxification mediated by cytochrome-P450-dependent monooxygenases contributes to imidacloprid resistance to some extent in the NJ-Imi strain. Results from synergist bioassays and cross-resistance patterns indicated that target-site insensitivity may be involved in imidacloprid resistance in the NJ-Imi strain of B. tabaci. Although oxidative detoxification mediated by P450 monooxygenases is involved in imidacloprid resistance in the NJ-Imi strain of B-type B. tabaci, target-site modification as an additional resistance mechanism cannot be ruled out. Considering the high risk of cross-resistance, neonicotinoids should be regarded as a single group when implementing an insecticide rotation scheme in B. tabaci control. (c) 2009 Society of Chemical Industry.

  13. Mechanisms of Antibiotic Resistance

    Science.gov (United States)

    Munita, Jose M.; Arias, Cesar A.

    2015-01-01

    Emergence of resistance among the most important bacterial pathogens is recognized as a major public health threat affecting humans worldwide. Multidrug-resistant organisms have emerged not only in the hospital environment but are now often identified in community settings, suggesting that reservoirs of antibiotic-resistant bacteria are present outside the hospital. The bacterial response to the antibiotic “attack” is the prime example of bacterial adaptation and the pinnacle of evolution. “Survival of the fittest” is a consequence of an immense genetic plasticity of bacterial pathogens that trigger specific responses that result in mutational adaptations, acquisition of genetic material or alteration of gene expression producing resistance to virtually all antibiotics currently available in clinical practice. Therefore, understanding the biochemical and genetic basis of resistance is of paramount importance to design strategies to curtail the emergence and spread of resistance and devise innovative therapeutic approaches against multidrug-resistant organisms. In this chapter, we will describe in detail the major mechanisms of antibiotic resistance encountered in clinical practice providing specific examples in relevant bacterial pathogens. PMID:27227291

  14. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... video) Animation of Antimicrobial Resistance (text version) Arabic Translation of Animation of Antimicrobial Resistance Chinese Translation of Animation of Antimicrobial Resistance French Translation of ...

  15. Mango resistance to fruit flies. II - resistance of the alfa cultivar

    Energy Technology Data Exchange (ETDEWEB)

    Rossetto, C.J.; Bortoletto, N., E-mail: rossetto@iac.sp.gov.b [Agencia Paulista de Tecnologia dos Agronegocios (APTA), Votuporanga, SP (Brazil). Polo Regional do Noroeste Paulista; Walder, J.M.M.; Mastrangelo, T. de A., E-mail: jmwalder@cena.usp.b [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil); Carvalho, C.R.L.; Castro, J.V. de, E-mail: climonta@iac.sp.gov.b, E-mail: josalba@iac.sp.gov.b [Instituto Agronomico de Campinas, SP (Brazil); Pinto, A.C. de Q. [EMBRAPA, Brasilia, DF (Brazil); Cortelazzo, A.L., E-mail: angelo@unicamp.b [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Biologia

    2006-07-01

    The percentage of infested mango fruits of five selected mango varieties was evaluated during three years under field conditions. Three varieties with field resistance to fruit flies had less then 10% of fruits infested. Tommy Atkins, the susceptible commercial check, had 42,9% and the susceptible check had 98.9 % of infested fruits. The three field resistant varieties plus the susceptible commercial check, Tommy Atkins, were further tested in laboratory, under caged conditions, with artificial infestation of Anastrepha obliqua. The attempts of oviposition and the number of pupae developed from each fruit were evaluated. Under caged conditions, the cultivar Alfa maintained its field resistance and Espada Stahl and IAC 111 lost the field resistance and were as susceptible as Tommy Atkins. The attempts of oviposition were positively and highly correlated with the number of pupae developed in the fruits. Non preference for oviposition was confirmed as the main mechanism of resistance of mango fruits to fruit flies. In the absence of a more susceptible variety (no choice test) the cultivar Alfa has kept the resistance (author)

  16. Mango resistance to fruit flies. II - resistance of the alfa cultivar

    International Nuclear Information System (INIS)

    Rossetto, C.J.; Bortoletto, N.; Carvalho, C.R.L.; Castro, J.V. de; Pinto, A.C. de Q.; Cortelazzo, A.L.

    2006-01-01

    The percentage of infested mango fruits of five selected mango varieties was evaluated during three years under field conditions. Three varieties with field resistance to fruit flies had less then 10% of fruits infested. Tommy Atkins, the susceptible commercial check, had 42,9% and the susceptible check had 98.9 % of infested fruits. The three field resistant varieties plus the susceptible commercial check, Tommy Atkins, were further tested in laboratory, under caged conditions, with artificial infestation of Anastrepha obliqua. The attempts of oviposition and the number of pupae developed from each fruit were evaluated. Under caged conditions, the cultivar Alfa maintained its field resistance and Espada Stahl and IAC 111 lost the field resistance and were as susceptible as Tommy Atkins. The attempts of oviposition were positively and highly correlated with the number of pupae developed in the fruits. Non preference for oviposition was confirmed as the main mechanism of resistance of mango fruits to fruit flies. In the absence of a more susceptible variety (no choice test) the cultivar Alfa has kept the resistance (author)

  17. Cross-resistance of bisultap resistant strain of Nilaparvata lugens and its biochemical mechanism.

    Science.gov (United States)

    Ling, Shanfeng; Zhang, Runjie

    2011-02-01

    The resistant (R) strain of the planthopper Nilaparvata lugens (Stål) selected for bisultap resistance displayed 7.7-fold resistance to bisultap and also had cross-resistance to nereistoxin (monosultap, thiocyclam, and cartap), chlorpyrifos, dimethoate, and malathion but no cross-resistance to buprofezin, imidacloprid, and fipronil. To find out the biochemical mechanism of resistance to bisultap, biochemical assay was done. The results showed that cytochrome P450 monooxygenases (P450) activity in R strain was 2.71-fold that in susceptible strain (S strain), in which the changed activity for general esterase (EST) was 1.91 and for glutathione S-transferases only 1.32. Piperonyl butoxide (PBO) could significantly inhibit P450 activity (percentage of inhibition [PI]: 37.31%) in the R strain, with ESTs PI = 16.04% by triphenyl phosphate (TPP). The results also demonstrated that diethyl maleate had no synergism with bisultap. However, PBO displayed significant synergism in three different strains, and the synergism increased with resistance (S strain 1.42, Lab strain, 2.24 and R strain, 3.23). TPP also showed synergism for three strains, especially in R strain (synergistic ratio = 2.47). An in vitro biochemical study and in vivo synergistic study indicated that P450 might be play important role in the biochemical mechanism of bisultap resistance and that esterase might be the important factor of bisultap resistance. Acetylcholinesterase (AChE) insensitivity play important role in bisultap resistance. We suggest that buprofezin, imidacloprid, and fipronil could be used in resistance management programs for N. lugens via alternation and rotation with bisultap.

  18. Drug-resistant tuberculosis in Sindh

    International Nuclear Information System (INIS)

    Almani, S.A.; Memon, N.M.; Qureshi, A.F.

    2002-01-01

    Objective: To assess the prevalence of primary and secondary drug resistance amongst the clinical isolates of M.tuberculosis, to identify risk factors and how to overcome this problem. Design: A case series of 50 indoor patients with sputum smear-positive pulmonary tuberculosis. Place and duration of Study: Department of Medicine, Liaquat University of Medical and Health Sciences Jamshoro, Sindh, (Pakistan) from January 1999 to December 2000. Patients and methods: Four first line anti-tuberculous drugs rifampicine, ethambutol and streptomycin were tested for sensitivity pattern. Results: Twelve (26.66%) were sensitive to all four drugs, 12(26.66%) were resistant to one drug, 14 (31.11%) were resistant to two drugs, 2 (4.44%) were resistant to three drugs, and 5(11.11%) were resistant to all four drugs. Resistance to isoniazid was the most common in 27 cases (60%) with primary resistance in 6(13.33%) and secondary resistance in 21(46.66%), followed by resistance to streptomycin in 17 cases (37.77%) with primary resistance in 5(11.11%) and secondary resistance in 12 (26.66%). Resistance to ethambutol in 10 cases (22.22%) and rifampicine in 11 (24.44%) and all cases were secondary. Similarly multi-drugs resistance (MRD) TB was found in 11(24.44%) isolates. Conclusion: This study showed high prevalence of drug resistance among clinical isolates of M. tuberculosis. Their is a need to establish centers at number of places with adequate facilities for susceptibility testing so that the resistant pattern could be ascertained and treatment regimens tailored accordingly. (author)

  19. Corrosion-resistant metal surfaces

    Science.gov (United States)

    Sugama, Toshifumi [Wading River, NY

    2009-03-24

    The present invention relates to metal surfaces having thereon an ultrathin (e.g., less than ten nanometer thickness) corrosion-resistant film, thereby rendering the metal surfaces corrosion-resistant. The corrosion-resistant film includes an at least partially crosslinked amido-functionalized silanol component in combination with rare-earth metal oxide nanoparticles. The invention also relates to methods for producing such corrosion-resistant films.

  20. Contribution of non-target-site resistance in imidazolinone-resistant Imisun sunflower

    Directory of Open Access Journals (Sweden)

    Gabriela Breccia

    2017-08-01

    Full Text Available ABSTRACT The first commercial herbicide-resistant trait in sunflower (Helianthus annuus L. is known as ‘Imisun’. Imidazolinone resistance in Imisun cultivars has been reported to be genetically controlled by a major gene (known as Imr1 or Ahasl1-1 and modifier genes. Imr1 is an allelic variant of the Ahasl1 locus that codes for the acetohydroxyacid synthase, which is the target site of these herbicides. The mechanism of resistance endowed by modifier genes has not been characterized and it could be related to non-target-site resistance. The objective of this study was to evaluate the role of cytochrome P450 monooxygenases (P450s in Imisun resistance. The response to imazapyr herbicide in combination with P450s inhibitor malathion was evaluated in 2 Imisun lines, IMI-1 and RHA426. Malathion reduced herbicide efficacy in both lines, but IMI-1 was affected in a greater extent. A significant reduction in plant growth in response to P450s inhibitors 1-aminobenzotriazole and piperonyl butoxide treatment was detected in the Imisun line HA425. The increased susceptibility to imazapyr after P450s-inhibitor treatment indicates that herbicide metabolism by P450s is a mechanism involved in Imisun resistance. These results also suggest the involvement of different P450s isozymes in endowing resistance to imazapyr in Imisun cultivars.

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

    Directory of Open Access Journals (Sweden)

    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.

  2. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    DEFF Research Database (Denmark)

    Gesche, Joanna; Khanevski, Marina; Solberg, Carl

    2017-01-01

    for refractory seizures. Resistance to valproic acid had a specificity of 100% to identify patients with drug resistance and correlated strongly with bad social outcome and seizure burden. Conversely, 21.2% of all patients with refractory seizures according to the ILAE definition later became seizure free...... (mainly with valproic acid). Our data suggest that "drug resistant GGE" must not be declared unless patients were adequately treated with valproic acid, and advocate resistance to valproic acid as a new clinical biomarker for drug-resistant GGE. A PowerPoint slide summarizing this article is available...

  5. Investigation and Treatment of Fusidic Acid Resistance Among Methicillin-Resistant Staphylococcal Isolates from Egypt.

    Science.gov (United States)

    Abouelfetouh, Alaa; Kassem, Mervat; Naguib, Marwa; El-Nakeeb, Moustafa

    2017-01-01

    Methicillin resistance among staphylococci isolated from patients in northern Egypt has escalated alarmingly in the past decade. Data about the prevalence of fusidic acid (FA) resistance in Egyptian clinical isolates are limited. This work investigates the prevalence and mechanism of FA resistance among 81 methicillin-resistant staphylococcal isolates from major hospitals of Alexandria, Egypt. Some combinations for treating infections due to resistant isolates were studied. Twenty-six isolates (32.1%) were FA resistant (minimum inhibitory concentrations [MICs] = 2-1,024 μg/ml), and fusB and fusC genes coding for FA resistance were detected in 30.77% and 34.62% of the FA-resistant strains, respectively. One highly resistant isolate, S502 (MIC = 1,024 μg/ml), possessed both genes. Plasmid curing resulted in fusB loss and MIC decrease by 16-64 folds. Conjugation caused acquisition of FA resistance among susceptible isolates. Serial passages in subinhibitory FA concentrations produced mutants with increased MIC by 4-32 folds. The combination of FA with rifampin, gentamicin, or ampicillin/sulbactam, in a subinhibitory concentration, was synergistic against the isolates, including serial passage mutants, decreasing number of survivors by an average of 2-4 logs. A relatively moderate rate of FA resistance was detected in Alexandria hospitals. Combination therapy with gentamicin, rifampin, or ampicillin/sulbactam is crucial to preserve the effectiveness of FA.

  6. 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...

  7. Hydraulic resistance of biofilms

    KAUST Repository

    Dreszer, C.; Vrouwenvelder, Johannes S.; Paulitsch-Fuchs, Astrid H.; Zwijnenburg, Arie; Kruithof, Joop C.; Flemming, Hans Curt

    2013-01-01

    resistance is very low compared to the expected biofilm resistance and, thus, biofilm resistance can be determined accurately. Transmembrane pressure drop was monitored. As biofilm parameters, thickness, total cell number, TOC, and extracellular polymeric

  8. Experimental Studies on the Changes in Resistivity and Its Anisotropy Using Electrical Resistivity Tomography

    Directory of Open Access Journals (Sweden)

    Tao Zhu

    2012-01-01

    Full Text Available Three measuring lines were arranged on one of free planes of magnetite cuboid samples. Apparent resistivity data were acquired by MIR-2007 resistivity meter when samples were under uniaxial compression of servocontrol YAW-5000F loadingmachine in laboratory. Then we constructed the residual resistivity images using electrical resistivity tomography (ERT and plotted the diagrams of apparent resistivity anisotropy coefficient (ARAC λ∗ and the included angle α between the major axis of apparent resistivity anisotropy ellipse and the axis of load with pressure and effective depth. Our results show that with increasing pressure, resistivity and the decreased (D region and increased (I region resistivity regions have complex behaviors, but when pressure is higher than a certain value, the average resistivity decrease and the area of D region expand gradually in all time with the increase of pressure, which may be significant to the monitoring and prediction of earthquake, volcanic activities, and large-scale geologic motions. The effects of pressure on λ∗ and α are not very outstanding for dry magnetite samples.

  9. Selection for chlorpyrifos resistance in Liriomyza sativae Blanchard: Cross-resistance patterns, stability and biochemical mechanisms.

    Science.gov (United States)

    Askari-Saryazdi, Ghasem; Hejazi, Mir Jalil; Ferguson, J Scott; Rashidi, Mohammad-Reza

    2015-10-01

    The vegetable leafminer (VLM), Liriomyza sativae (Diptera: Agromyzidae) is a serious pest of vegetable crops and ornamentals worldwide. In cropping systems with inappropriate management strategies, development of resistance to insecticides in leafminers is probable. Chlorpyrifos is a commonly used pesticide for controlling leafminers in Iran, but resistance to this insecticide in leafminers has not been characterized. In order to develop strategies to minimize resistance in the field and greenhouse, a laboratory selected chlorpyrifos resistant strain of L. sativae was used to characterize resistance and determine the rate of development and stability of resistance. Selecting for resistance in the laboratory after 23 generations yielded a chlorpyrifos resistant selected strain (CRSS) with a resistance ratio of 40.34, determined on the larval stage. CRSS exhibited no cross-resistance to other tested insecticides except for diazinon. Synergism and biochemical assays indicated that esterases (EST) had a key role in metabolic resistance to chlorpyrifos, but glutathione S-transferase (GST) and mixed function oxidase (MFO) were not mediators in this resistance. In CRSS acetylcholinesterase (AChE) was more active than the susceptible strain, Sharif (SH). AChE in CRSS was also less sensitive to inhibition by propoxur. The kinetics parameters (Km and Vmax) of AChE indicated that affinities and hydrolyzing efficiencies of this enzyme in CRSS were higher than SH. Susceptibility to chlorpyrifos in L. sativae was re-gained in the absence of insecticide pressure. Synergism, biochemical and cross-resistance assays revealed that overactivity of metabolic enzymes and reduction in target site sensitivity are probably joint factors in chlorpyrifos resistance. An effective insecticide resistance management program is necessary to prevent fast resistance development in crop systems. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Resistance of Bacteria to Biocides.

    Science.gov (United States)

    Maillard, Jean-Yves

    2018-04-01

    Biocides and formulated biocides are used worldwide for an increasing number of applications despite tightening regulations in Europe and in the United States. One concern is that such intense usage of biocides could lead to increased bacterial resistance to a product and cross-resistance to unrelated antimicrobials including chemotherapeutic antibiotics. Evidence to justify such a concern comes mostly from the use of health care-relevant bacterial isolates, although the number of studies of the resistance characteristics of veterinary isolates to biocides have increased the past few years. One problem remains the definition of "resistance" and how to measure resistance to a biocide. This has yet to be addressed globally, although the measurement of resistance is becoming more pressing, with regulators both in Europe and in the United States demanding that manufacturers provide evidence that their biocidal products will not impact on bacterial resistance. Alongside in vitro evidence of potential antimicrobial cross-resistance following biocide exposure, our understanding of the mechanisms of bacterial resistance and, more recently, our understanding of the effect of biocides to induce a mechanism(s) of resistance in bacteria has improved. This article aims to provide an understanding of the development of antimicrobial resistance in bacteria following a biocide exposure. The sections provide evidence of the occurrence of bacterial resistance and its mechanisms of action and debate how to measure bacterial resistance to biocides. Examples pertinent to the veterinary field are used where appropriate.

  11. Systematic drug screening reveals specific vulnerabilities and co-resistance patterns in endocrine-resistant breast cancer.

    Science.gov (United States)

    Kangaspeska, Sara; Hultsch, Susanne; Jaiswal, Alok; Edgren, Henrik; Mpindi, John-Patrick; Eldfors, Samuli; Brück, Oscar; Aittokallio, Tero; Kallioniemi, Olli

    2016-07-04

    The estrogen receptor (ER) inhibitor tamoxifen reduces breast cancer mortality by 31 % and has served as the standard treatment for ER-positive breast cancers for decades. However, 50 % of advanced ER-positive cancers display de novo resistance to tamoxifen, and acquired resistance evolves in 40 % of patients who initially respond. Mechanisms underlying resistance development remain poorly understood and new therapeutic opportunities are urgently needed. Here, we report the generation and characterization of seven tamoxifen-resistant breast cancer cell lines from four parental strains. Using high throughput drug sensitivity and resistance testing (DSRT) with 279 approved and investigational oncology drugs, exome-sequencing and network analysis, we for the first time, systematically determine the drug response profiles specific to tamoxifen resistance. We discovered emerging vulnerabilities towards specific drugs, such as ERK1/2-, proteasome- and BCL-family inhibitors as the cells became tamoxifen-resistant. Co-resistance to other drugs such as the survivin inhibitor YM155 and the chemotherapeutic agent paclitaxel also occurred. This study indicates that multiple molecular mechanisms dictate endocrine resistance, resulting in unexpected vulnerabilities to initially ineffective drugs, as well as in emerging co-resistances. Thus, combatting drug-resistant tumors will require patient-tailored strategies in order to identify new drug vulnerabilities, and to understand the associated co-resistance patterns.

  12. Camptothecin resistance

    DEFF Research Database (Denmark)

    Brangi, M; Litman, Thomas; Ciotti, M

    1999-01-01

    . Glucuronides were found at equal levels in both parental and resistant colon cancer cell lines for epirubicin and to a lesser extent for SN-38 and mitoxantrone. Low levels of glucuronidation could also be detected in the resistant breast cancer cells. These results were confirmed by analysis of the UGT1A...

  13. Regicide and Resistance

    DEFF Research Database (Denmark)

    Flohr, Mikkel

    2016-01-01

    This article examines the role of resistance in Michel Foucault’s political thought. The article recovers this otherwise obscured aspect of Foucault’s thought through a systematic analysis of his theoretical regicide and consequent reconceptualization of power, agency and resistance. It is argued...... that Foucault developed a highly original account of resistance, which was, and should continue to be considered, central to his thought and its critical potential. It is shown how Foucault’s concept of resistance overcomes the limitation of voluntarism and determinism, which continue to mare contemporary...... political theory, providing a passage from the critique of contemporary configurations of power to the irrepressible possibility that they may be contested and changed....

  14. The effect of electrode contact resistance and capacitive coupling on Complex Resistivity measurements

    DEFF Research Database (Denmark)

    Ingeman-Nielsen, Thomas

    2006-01-01

    The effect of electrode contact resistance and capacitive coupling on complex resistivity (CR) measurements is studied in this paper. An equivalent circuit model for the receiver is developed to describe the effects. The model shows that CR measurements are severely affected even at relatively lo...... with the contact resistance artificially increased by resistors. The results emphasize the importance of keeping contact resistance low in CR measurements....

  15. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... Veterinary Safety & Health Antimicrobial Resistance Animation of Antimicrobial Resistance Share Tweet Linkedin Pin it More sharing options ... produced a nine-minute animation explaining how antimicrobial resistance both emerges and proliferates among bacteria. Over time, ...

  16. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... Animal & Veterinary Safety & Health Antimicrobial Resistance Animation of Antimicrobial Resistance Share Tweet Linkedin Pin it More sharing ... CVM) produced a nine-minute animation explaining how antimicrobial resistance both emerges and proliferates among bacteria. Over ...

  17. Phenotypic Resistance to Antibiotics

    Directory of Open Access Journals (Sweden)

    Jose L. Martinez

    2013-04-01

    Full Text Available The development of antibiotic resistance is usually associated with genetic changes, either to the acquisition of resistance genes, or to mutations in elements relevant for the activity of the antibiotic. However, in some situations resistance can be achieved without any genetic alteration; this is called phenotypic resistance. Non-inherited resistance is associated to specific processes such as growth in biofilms, a stationary growth phase or persistence. These situations might occur during infection but they are not usually considered in classical susceptibility tests at the clinical microbiology laboratories. Recent work has also shown that the susceptibility to antibiotics is highly dependent on the bacterial metabolism and that global metabolic regulators can modulate this phenotype. This modulation includes situations in which bacteria can be more resistant or more susceptible to antibiotics. Understanding these processes will thus help in establishing novel therapeutic approaches based on the actual susceptibility shown by bacteria during infection, which might differ from that determined in the laboratory. In this review, we discuss different examples of phenotypic resistance and the mechanisms that regulate the crosstalk between bacterial metabolism and the susceptibility to antibiotics. Finally, information on strategies currently under development for diminishing the phenotypic resistance to antibiotics of bacterial pathogens is presented.

  18. Resistance and Resistant Reaction of Gossypium arboreum to the Reniform, Nematode, Rotylenchulus reniformis

    Science.gov (United States)

    Carter, William W.

    1981-01-01

    Gossypium arboreum 'Nanking CB 1402' possessed a high level of resistance to Rotylenchulus reniformis. Within 16 h, the nematode penetrated roots of resistant and susceptible cottons equally. After 36 h, significantly fewer nematodes were found in resistant roots. Larvae fed in either an endodermal or pericyclic cell and had no specificity for root tissue of a particular age. In roots of resistant G. arboreum '1402,' wall breakdown of pericyclic cells was evident after 3 d, endodermal and cortical cells collapsed, and the hypertrophied pericyclic cells disintegrated within 12 d. Cell walls immediately adjacent to the nematode's head were thickened and more safranin positive in resistant than in susceptible cotton cultivars. Several other cultivars of G. arboreum were also resistant to R. reniformis, based on nematode fecundity and percent egg reduction. PMID:19300777

  19. Metabolic Resistance in Bed Bugs

    Directory of Open Access Journals (Sweden)

    Omprakash Mittapalli

    2011-03-01

    Full Text Available Blood-feeding insects have evolved resistance to various insecticides (organochlorines, pyrethroids, carbamates, etc. through gene mutations and increased metabolism. Bed bugs (Cimex lectularius are hematophagous ectoparasites that are poised to become one of the major pests in households throughout the United States. Currently, C. lectularius has attained a high global impact status due to its sudden and rampant resurgence. Resistance to pesticides is one factor implicated in this phenomenon. Although much emphasis has been placed on target sensitivity, little to no knowledge is available on the role of key metabolic players (e.g., cytochrome P450s and glutathione S-transferases towards pesticide resistance in C. lectularius. In this review, we discuss different modes of resistance (target sensitivity, penetration resistance, behavioral resistance, and metabolic resistance with more emphasis on metabolic resistance.

  20. Molecular Detection of Antimicrobial Resistance

    Science.gov (United States)

    Fluit, Ad C.; Visser, Maarten R.; Schmitz, Franz-Josef

    2001-01-01

    The determination of antimicrobial susceptibility of a clinical isolate, especially with increasing resistance, is often crucial for the optimal antimicrobial therapy of infected patients. Nucleic acid-based assays for the detection of resistance may offer advantages over phenotypic assays. Examples are the detection of the methicillin resistance-encoding mecA gene in staphylococci, rifampin resistance in Mycobacterium tuberculosis, and the spread of resistance determinants across the globe. However, molecular assays for the detection of resistance have a number of limitations. New resistance mechanisms may be missed, and in some cases the number of different genes makes generating an assay too costly to compete with phenotypic assays. In addition, proper quality control for molecular assays poses a problem for many laboratories, and this results in questionable results at best. The development of new molecular techniques, e.g., PCR using molecular beacons and DNA chips, expands the possibilities for monitoring resistance. Although molecular techniques for the detection of antimicrobial resistance clearly are winning a place in routine diagnostics, phenotypic assays are still the method of choice for most resistance determinations. In this review, we describe the applications of molecular techniques for the detection of antimicrobial resistance and the current state of the art. PMID:11585788

  1. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... Animal & Veterinary Safety & Health Antimicrobial Resistance Animation of Antimicrobial Resistance Share Tweet Linkedin Pin it More sharing options ... CVM) produced a nine-minute animation explaining how antimicrobial resistance both emerges and proliferates among bacteria. Over time, ...

  2. Fate of antibiotic resistant bacteria and genes during wastewater chlorination: implication for antibiotic resistance control.

    Directory of Open Access Journals (Sweden)

    Qing-Bin Yuan

    Full Text Available This study investigated fates of nine antibiotic-resistant bacteria as well as two series of antibiotic resistance genes in wastewater treated by various doses of chlorine (0, 15, 30, 60, 150 and 300 mg Cl2 min/L. The results indicated that chlorination was effective in inactivating antibiotic-resistant bacteria. Most bacteria were inactivated completely at the lowest dose (15 mg Cl2 min/L. By comparison, sulfadiazine- and erythromycin-resistant bacteria exhibited tolerance to low chlorine dose (up to 60 mg Cl2 min/L. However, quantitative real-time PCRs revealed that chlorination decreased limited erythromycin or tetracycline resistance genes, with the removal levels of overall erythromycin and tetracycline resistance genes at 0.42 ± 0.12 log and 0.10 ± 0.02 log, respectively. About 40% of erythromycin-resistance genes and 80% of tetracycline resistance genes could not be removed by chlorination. Chlorination was considered not effective in controlling antimicrobial resistance. More concern needs to be paid to the potential risk of antibiotic resistance genes in the wastewater after chlorination.

  3. Hydraulic resistance of biofilms

    KAUST Repository

    Dreszer, C.

    2013-02-01

    Biofilms may interfere with membrane performance in at least three ways: (i) increase of the transmembrane pressure drop, (ii) increase of feed channel (feed-concentrate) pressure drop, and (iii) increase of transmembrane passage. Given the relevance of biofouling, it is surprising how few data exist about the hydraulic resistance of biofilms that may affect the transmembrane pressure drop and membrane passage. In this study, biofilms were generated in a lab scale cross flow microfiltration system at two fluxes (20 and 100Lm-2h-1) and constant cross flow (0.1ms-1). As a nutrient source, acetate was added (1.0mgL-1 acetate C) besides a control without nutrient supply. A microfiltration (MF) membrane was chosen because the MF membrane resistance is very low compared to the expected biofilm resistance and, thus, biofilm resistance can be determined accurately. Transmembrane pressure drop was monitored. As biofilm parameters, thickness, total cell number, TOC, and extracellular polymeric substances (EPS) were determined, it was demonstrated that no internal membrane fouling occurred and that the fouling layer actually consisted of a grown biofilm and was not a filter cake of accumulated bacterial cells. At 20Lm-2h-1 flux with a nutrient dosage of 1mgL-1 acetate C, the resistance after 4 days reached a value of 6×1012m-1. At 100Lm-2h-1 flux under the same conditions, the resistance was 5×1013m-1. No correlation of biofilm resistance to biofilm thickness was found; Biofilms with similar thickness could have different resistance depending on the applied flux. The cell number in biofilms was between 4×107 and 5×108 cellscm-2. At this number, bacterial cells make up less than a half percent of the overall biofilm volume and therefore did not hamper the water flow through the biofilm significantly. A flux of 100Lm-2h-1 with nutrient supply caused higher cell numbers, more biomass, and higher biofilm resistance than a flux of 20Lm-2h-1. However, the biofilm thickness

  4. Cross-resistance and biochemical mechanisms of resistance to indoxacarb in the diamondback moth, Plutella xylostella.

    Science.gov (United States)

    Zhang, Shuzhen; Zhang, Xiaolei; Shen, Jun; Li, Dongyang; Wan, Hu; You, Hong; Li, Jianhong

    2017-08-01

    Indoxacarb belongs to a class of insecticides known as oxadiazines and is the first commercialized pyrazoline-type voltage-dependent sodium channel blocker. A moderate level of resistance to indoxacarb has evolved in field populations of Plutella xylostella from Central China. In the present study, cross-resistance, resistance stability and metabolic mechanisms of indoxacarb resistance were investigated in this moth species. A P. xylostella strain with a high level of resistance to indoxacarb was obtained through continuous selection in the laboratory. The strain showed cross-resistance to metaflumizone, beta-cypermethrin and chlorfenapyr, but no resistance to cyantraniliprole, chlorantraniliprole, abamectin, chlorfluazuron, spinosad and diafenthiuron compared with the susceptible strain. Synergism tests revealed that piperonyl butoxide (PBO) (synergistic ratio, SR=7.8) and diethyl maleate (DEF) (SR=3.5) had considerable synergistic effects on indoxacarb toxicity in the resistant strain (F 58 ). Enzyme activity data showed there was an approximate 5.8-fold different in glutathione S-transferase (GST) and a 6.8-fold different in cytochrome P450 monooxygenase between the resistant strain (F 58 ) and susceptible strain, suggesting that the increased activity of these two enzymes is likely the main detoxification mechanism responsible for the species' resistance to indoxacarb. These results will be helpful for insecticide resistance management strategies to delay the development of indoxacarb resistance in fields. Copyright © 2017. Published by Elsevier Inc.

  5. Multi-Electrode Resistivity Probe for Investigation of Local Temperature Inside Metal Shell Battery Cells via Resistivity: Experiments and Evaluation of Electrical Resistance Tomography

    Directory of Open Access Journals (Sweden)

    Xiaobin Hong

    2015-01-01

    Full Text Available Direct Current (DC electrical resistivity is a material property that is sensitive to temperature changes. In this paper, the relationship between resistivity and local temperature inside steel shell battery cells (two commercial 10 Ah and 4.5 Ah lithium-ion cells is innovatively studied by Electrical Resistance Tomography (ERT. The Schlumberger configuration in ERT is applied to divide the cell body into several blocks distributed in different levels, where the apparent resistivities are measured by multi-electrode surface probes. The investigated temperature ranges from −20 to 80 °C. Experimental results have shown that the resistivities mainly depend on temperature changes in each block of the two cells used and the function of the resistivity and temperature can be fitted to the ERT-measurement results in the logistical-plot. Subsequently, the dependence of resistivity on the state of charge (SOC is investigated, and the SOC range of 70%–100% has a remarkable impact on the resistivity at low temperatures. The proposed approach under a thermal cool down regime is demonstrated to monitor the local transient temperature.

  6. Oxidation-resistant cermet

    Science.gov (United States)

    Phillips, W. M.

    1977-01-01

    Chromium metal alloys and chromium oxide ceramic are combined to produce cermets with oxidation-resistant properties. Application of cermets includes use in hot corrosive environments requiring strong resistive materials.

  7. Low Prevalence of Carbapenem-Resistant Bacteria in River Water: Resistance Is Mostly Related to Intrinsic Mechanisms.

    Science.gov (United States)

    Tacão, Marta; Correia, António; Henriques, Isabel S

    2015-10-01

    Carbapenems are last-resort antibiotics to handle serious infections caused by multiresistant bacteria. The incidence of resistance to these antibiotics has been increasing and new resistance mechanisms have emerged. The dissemination of carbapenem resistance in the environment has been overlooked. The main goal of this research was to assess the prevalence and diversity of carbapenem-resistant bacteria in riverine ecosystems. The presence of frequently reported carbapenemase-encoding genes was inspected. The proportion of imipenem-resistant bacteria was on average 2.24 CFU/ml. Imipenem-resistant strains (n=110) were identified as Pseudomonas spp., Stenotrophomonas maltophilia, Aeromonas spp., Chromobacterium haemolyticum, Shewanella xiamenensis, and members of Enterobacteriaceae. Carbapenem-resistant bacteria were highly resistant to other beta-lactams such as quinolones, aminoglycosides, chloramphenicol, tetracyclines, and sulfamethoxazole/trimethoprim. Carbapenem resistance was mostly associated with intrinsically resistant bacteria. As intrinsic resistance mechanisms, we have identified the blaCphA gene in 77.3% of Aeromonas spp., blaL1 in all S. maltophilia, and blaOXA-48-like in all S. xiamenensis. As acquired resistance mechanisms, we have detected the blaVIM-2 gene in six Pseudomonas spp. (5.45%). Integrons with gene cassettes encoding resistance to aminoglycosides (aacA and aacC genes), trimethoprim (dfrB1b), and carbapenems (blaVIM-2) were found in Pseudomonas spp. Results suggest that carbapenem resistance dissemination in riverine ecosystems is still at an early stage. Nevertheless, monitoring these aquatic compartments for the presence of resistance genes and its host organisms is essential to outline strategies to minimize resistance dissemination.

  8. Antimicrobial resistance of thermophilic Campylobacter

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Engberg, J.

    2001-01-01

    Campylobacter has become the leading cause of zoonotic enteric infections in developed and developing countries world-wide. Antimicrobial resistance has emerged among Campylobacter mainly as a consequence of the use of antimicrobial agents in food animal production. Resistance to drugs of choice...... for the treatment of infections, macrolides and fluoroquinolones has emerged as a clinical problem and interventions to reduce this are recommended. Resistance to fluoroquinolones and macrolides is mediated by chromosomal mutations. Resistance to other relevant antimicrobial agents, mediated by acquired resistance...... genes, has not become widespread so far. However, resistance genes originating from both Gram-positive and Gram-negative bacterial species have been found, showing the potential for acquired resistance to emerge in Campylobacter....

  9. Resistance patterns and trends of extensively drug-resistant tuberculosis: 5-year experience

    Directory of Open Access Journals (Sweden)

    Amresh Kumar Singh

    2013-12-01

    Full Text Available Objective:Extensively drug-resistant tuberculosis (XDR-TB strains were emerged when multidrug-resistant TB (MDR- TB was inadequately treated. Inadequate treatment of MDR-TB cases may result in additional resistance especially non-XDR-TB and then XDR-TB. The aim of this study was to know the prevalence, resistance patterns and trends of the XDR-TB strains among the MDR-TB at a tertiary care hospital in Lucknow, India Methods: A total of 430 Mycobacterium isolates were underwent NAP test and TB MPT64 Ag test for the identification of Mycobacterium tuberculosis complex (MTBC. Drug-susceptibility test (DST was performed over MTBC for the first line drugs by 1% proportion method (Bactec and for the second-line drugs by 1% proportion method (Lowenstein- Jensen media. The XDR-TB status was further confirmed by line probe assay (GenoType® MTBDRsl assay. Results: Among the 430 isolates of mycobacterium, 365 (84.9% were MTBC and 139 (38.1% were MDR-TB respectively. Further 97 MDR-TB from “highly suspected drug resistant-TB (DR-TB” cases among MDR-TB were tested with second line drugs in which 15 (15.5% XDR-TB and 82 (84.5% were non-XDR-TB. Regarding XDR-TB status, using the 1% proportion method a 100% agreement was seen with the GenoType® MTBDRsl assay. Resistance patterns of XDR-TB were as; 10/15 (66.7% as isoniazid + rifampicin + ciprofloxacin + amikacin resistance and 5/15 (33.3% as isoniazid + rifampicin + ciprofloxacin + amikacin + kanamycin resistance. Conclusion:The prevalence of XDR-TB was 15.5% among MDR-TB. Hence laboratory testing of “highly suspected drug resistant-TB” isolates should be done for both first and second line drugs simultaneously especially in developing countries.J Microbiol Infect Dis 2013;3(4: 169-175

  10. Challenges to Resistance Welding

    DEFF Research Database (Denmark)

    Song, Quanfeng

    This report originates from the compulsory defense during my Ph.D. study at the Technical University of Denmark. Resistance welding is an old and well-proven technology. Yet the emergence of more and more new materials, new designs, invention off new joining techniques, and more stringent...... requirement in quality have imposed challenges to the resistance welding. More some research and development have to be done to adapt the old technology to the manufacturing industry of the 21st century. In the 1st part of the report, the challenging factors to the resistance welding are reviewed. Numerical...... simulation of resistance welding has been under development for many years. Yet it is no easy to make simulation results reliable and accurate because of the complexity of resistance welding process. In the 2nd part of the report numerical modeling of resistance welding is reviewed, some critical factors...

  11. Method of separate determination of high-ohmic sample resistance and contact resistance

    Directory of Open Access Journals (Sweden)

    Vadim A. Golubiatnikov

    2015-09-01

    Full Text Available A method of separate determination of two-pole sample volume resistance and contact resistance is suggested. The method is applicable to high-ohmic semiconductor samples: semi-insulating gallium arsenide, detector cadmium-zinc telluride (CZT, etc. The method is based on near-contact region illumination by monochromatic radiation of variable intensity from light emitting diodes with quantum energies exceeding the band gap of the material. It is necessary to obtain sample photo-current dependence upon light emitting diode current and to find the linear portion of this dependence. Extrapolation of this linear portion to the Y-axis gives the cut-off current. As the bias voltage is known, it is easy to calculate sample volume resistance. Then, using dark current value, one can determine the total contact resistance. The method was tested for n-type semi-insulating GaAs. The contact resistance value was shown to be approximately equal to the sample volume resistance. Thus, the influence of contacts must be taken into account when electrophysical data are analyzed.

  12. Efflux-mediated antimicrobial resistance.

    Science.gov (United States)

    Poole, Keith

    2005-07-01

    Antibiotic resistance continues to plague antimicrobial chemotherapy of infectious disease. And while true biocide resistance is as yet unrealized, in vitro and in vivo episodes of reduced biocide susceptibility are common and the history of antibiotic resistance should not be ignored in the development and use of biocidal agents. Efflux mechanisms of resistance, both drug specific and multidrug, are important determinants of intrinsic and/or acquired resistance to these antimicrobials, with some accommodating both antibiotics and biocides. This latter raises the spectre (as yet generally unrealized) of biocide selection of multiple antibiotic-resistant organisms. Multidrug efflux mechanisms are broadly conserved in bacteria, are almost invariably chromosome-encoded and their expression in many instances results from mutations in regulatory genes. In contrast, drug-specific efflux mechanisms are generally encoded by plasmids and/or other mobile genetic elements (transposons, integrons) that carry additional resistance genes, and so their ready acquisition is compounded by their association with multidrug resistance. While there is some support for the latter efflux systems arising from efflux determinants of self-protection in antibiotic-producing Streptomyces spp. and, thus, intended as drug exporters, increasingly, chromosomal multidrug efflux determinants, at least in Gram-negative bacteria, appear not to be intended as drug exporters but as exporters with, perhaps, a variety of other roles in bacterial cells. Still, given the clinical significance of multidrug (and drug-specific) exporters, efflux must be considered in formulating strategies/approaches to treating drug-resistant infections, both in the development of new agents, for example, less impacted by efflux and in targeting efflux directly with efflux inhibitors.

  13. 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.

  14. Antibiotic resistance in animals.

    Science.gov (United States)

    Barton, Mary D; Pratt, Rachael; Hart, Wendy S

    2003-01-01

    There is currently no systematic surveillance or monitoring of antibiotic resistance in Australian animals. Registration of antibiotics for use in animals is tightly controlled and has been very conservative. Fluoroquinolones have not been registered for use in food producing animals and other products have been removed from the market because of human health concerns. In the late 1970s, the Animal Health Committee coordinated a survey of resistance in Salmonella and Escherichia coli isolates from cattle, pigs and poultry and in bovine Staphylococcus aureus. Some additional information is available from published case reports. In samples collected prior to the withdrawal of avoparcin from the market, no vancomycin resistant Enterococcus faecium or Enterococcus faecalis were detected in samples collected from pigs, whereas some vanA enterococci, including E. faecium and E. faecalis, were found in chickens. No vanB enterococci were detected in either species. Virginiamycin resistance was common in both pig and poultry isolates. Multiple resistance was common in E. coli and salmonellae isolates. No fluoroquinolone resistance was found in salmonellae, E. coli or Campylobacter. Beta-lactamase production is common in isolates from bovine mastitis, but no methicillin resistance has been detected. However, methicillin resistance has been reported in canine isolates of Staphylococcus intermedius and extended spectrum beta-lactamase producing E. coli has been found in dogs.

  15. Systematic drug screening reveals specific vulnerabilities and co-resistance patterns in endocrine-resistant breast cancer

    International Nuclear Information System (INIS)

    Kangaspeska, Sara; Hultsch, Susanne; Jaiswal, Alok; Edgren, Henrik; Mpindi, John-Patrick; Eldfors, Samuli; Brück, Oscar; Aittokallio, Tero; Kallioniemi, Olli

    2016-01-01

    The estrogen receptor (ER) inhibitor tamoxifen reduces breast cancer mortality by 31 % and has served as the standard treatment for ER-positive breast cancers for decades. However, 50 % of advanced ER-positive cancers display de novo resistance to tamoxifen, and acquired resistance evolves in 40 % of patients who initially respond. Mechanisms underlying resistance development remain poorly understood and new therapeutic opportunities are urgently needed. Here, we report the generation and characterization of seven tamoxifen-resistant breast cancer cell lines from four parental strains. Using high throughput drug sensitivity and resistance testing (DSRT) with 279 approved and investigational oncology drugs, exome-sequencing and network analysis, we for the first time, systematically determine the drug response profiles specific to tamoxifen resistance. We discovered emerging vulnerabilities towards specific drugs, such as ERK1/2-, proteasome- and BCL-family inhibitors as the cells became tamoxifen-resistant. Co-resistance to other drugs such as the survivin inhibitor YM155 and the chemotherapeutic agent paclitaxel also occurred. This study indicates that multiple molecular mechanisms dictate endocrine resistance, resulting in unexpected vulnerabilities to initially ineffective drugs, as well as in emerging co-resistances. Thus, combatting drug-resistant tumors will require patient-tailored strategies in order to identify new drug vulnerabilities, and to understand the associated co-resistance patterns. The online version of this article (doi:10.1186/s12885-016-2452-5) contains supplementary material, which is available to authorized users

  16. Ciprofloxacin-resistant Escherichia coli in Central Greece: mechanisms of resistance and molecular identification

    Directory of Open Access Journals (Sweden)

    Mavroidi Angeliki

    2012-12-01

    Full Text Available Abstract Background Fluoroquinolone resistant E. coli isolates, that are also resistant to other classes of antibiotics, is a significant challenge to antibiotic treatment and infection control policies. In Central Greece a significant increase of ciprofloxacin-resistant Escherichia coli has occurred during 2011, indicating the need for further analysis. Methods A total of 106 ciprofloxacin-resistant out of 505 E. coli isolates consecutively collected during an eight months period in a tertiary Greek hospital of Central Greece were studied. Antimicrobial susceptibility patterns and mechanisms of resistance to quinolones were assessed, whereas selected isolates were further characterized by multilocus sequence typing and β-lactamase content. Results Sequence analysis of the quinolone-resistance determining region of the gyrA and parC genes has revealed that 63% of the ciprofloxacin-resistant E. coli harbored a distinct amino acid substitution pattern (GyrA:S83L + D87N; ParC:S80I + E84V, while 34% and 3% carried the patterns GyrA:S83L + D87N; ParC:S80I and GyrA:S83L + D87N; ParC:S80I + E84G respectively. The aac (6’-1b-cr plasmid-mediated quinolone resistance determinant was also detected; none of the isolates was found to carry the qnrA, qnrB and qnrS. Genotyping of a subset of 35 selected ciprofloxacin-resistant E. coli by multilocus sequence typing has revealed the presence of nine sequence types; ST131 and ST410 were the most prevalent and were exclusively correlated with hospital and health care associated infections, while strains belonging to STs 393, 361 and 162 were associated with community acquired infections. The GyrA:S83L + D87N; ParC:S80I + E84V substitution pattern was found exclusively among ST131 ciprofloxacin-resistant E. coli. Extended-spectrum β-lactamase-positive ST131 ciprofloxacin-resistant isolates produced CTX-M-type enzymes; eight the CTX-M-15 and one the CTX-M-3 variant. CTX-M-1 like and KPC-2 enzymes were detected

  17. Predictable Phenotypes of Antibiotic Resistance Mutations.

    Science.gov (United States)

    Knopp, M; Andersson, D I

    2018-05-15

    Antibiotic-resistant bacteria represent a major threat to our ability to treat bacterial infections. Two factors that determine the evolutionary success of antibiotic resistance mutations are their impact on resistance level and the fitness cost. Recent studies suggest that resistance mutations commonly show epistatic interactions, which would complicate predictions of their stability in bacterial populations. We analyzed 13 different chromosomal resistance mutations and 10 host strains of Salmonella enterica and Escherichia coli to address two main questions. (i) Are there epistatic interactions between different chromosomal resistance mutations? (ii) How does the strain background and genetic distance influence the effect of chromosomal resistance mutations on resistance and fitness? Our results show that the effects of combined resistance mutations on resistance and fitness are largely predictable and that epistasis remains rare even when up to four mutations were combined. Furthermore, a majority of the mutations, especially target alteration mutations, demonstrate strain-independent phenotypes across different species. This study extends our understanding of epistasis among resistance mutations and shows that interactions between different resistance mutations are often predictable from the characteristics of the individual mutations. IMPORTANCE The spread of antibiotic-resistant bacteria imposes an urgent threat to public health. The ability to forecast the evolutionary success of resistant mutants would help to combat dissemination of antibiotic resistance. Previous studies have shown that the phenotypic effects (fitness and resistance level) of resistance mutations can vary substantially depending on the genetic context in which they occur. We conducted a broad screen using many different resistance mutations and host strains to identify potential epistatic interactions between various types of resistance mutations and to determine the effect of strain

  18. 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...

  19. Glyphosate-Resistant Goosegrass from Mississippi

    Directory of Open Access Journals (Sweden)

    Vijay K. Nandula

    2013-05-01

    Full Text Available A suspected glyphosate-resistant goosegrass [Eleusine indica (L. Gaertn.] population, found in Washington County, Mississippi, was studied to determine the level of resistance and whether the resistance was due to a point mutation, as was previously identified in a Malaysian population. Whole plant dose response assays indicated a two- to four-fold increase in resistance to glyphosate. Leaf disc bioassays based on a glyphosate-dependent increase in shikimate levels indicated a five- to eight-fold increase in resistance. Sequence comparisons of messenger RNA for epsps, the gene encoding the enzyme 5-enolpyruvylshikimate-3-phosphate synthase, from resistant and sensitive goosegrass, revealed a cytosine to thymine nucleotide change at position 319 in the resistant accessions. This single nucleotide polymorphism causes a proline to serine amino acid substitution at position 106 in 5-enolpyruvylshikimate-3-phosphate synthase. A real-time polymerase chain reaction assay using DNA probes specific for the nucleotide change at position 319 was developed to detect this polymorphism. Goosegrass from 42 locations were screened, and the results indicated that glyphosate-resistant goosegrass remained localized to where it was discovered. Pendimethalin, s-metolachlor, clethodim, paraquat and fluazifop controlled resistant goosegrass 93% to 100%, indicating that several control options for glyphosate-resistant goosegrass are available.

  20. Treatment Options for Carbapenem-Resistant and Extensively Drug-Resistant Acinetobacter baumannii Infections

    Science.gov (United States)

    Viehman, J. Alexander; Nguyen, Minh-Hong; Doi, Yohei

    2014-01-01

    Acinetobacter baumannii is a leading cause of healthcare-associated infections worldwide. Due to various intrinsic and acquired mechanisms of resistance, most β-lactam agents are not effective against many strains, and carbapenems have played an important role in therapy. Recent trends show many infections are caused by carbapenem-resistant, or even extensively drug-resistant (XDR) strains, for which effective therapy is not well established. Evidence to date suggests that colistin constitutes the backbone of therapy, but the unique pharmacokinetic properties of colistin have led many to suggest the use of combination antimicrobial therapy. However, the combination of agents and dosing regimens that delivers the best clinical efficacy while minimizing toxicity is yet to be defined. Carbapenems, sulbactam, rifampin and tigecycline have been the most studied in the context of combination therapy. Most data regarding therapy for invasive, resistant A. baumannii infections come from uncontrolled case series and retrospective analyses, though some clinical trials have been completed and others are underway. Early institution of appropriate antimicrobial therapy is shown to consistently improve survival of patients with carbapenem-resistant and XDR A. baumannii infection, but the choice of empiric therapy in these infections remains an open question. This review summarizes the most current knowledge regarding the epidemiology, mechanisms of resistance, and treatment considerations of carbapenem-resistant and XDR A. baumannii. PMID:25091170

  1. NEW AND RARE PLANTS FOR THE FLORA OF CENTRAL SIBERIА

    Directory of Open Access Journals (Sweden)

    V. I. Kurbatsky

    2015-04-01

    Full Text Available Three species (Ceratophyllum submersum L., Astragalus glycyphyllos L., Centaurea apiculata Ledeb. are reported for the first time for the flora of Central Siberia and two species (Amoria hybrida (L. C. Presl, Thyselium palustre (L. Rafin. for the flora of Khakassia. New localities of four rare species (Hackelia thymifolia (DC. Johnston, Chaenorhinum minus (L. Willk. et Lange, Orobanche uralensis G. Beck, Valeriana alternifolia Ledeb. of the flora of the Republic of Khakassia are also given.

  2. Biological improvement of radiation resistance

    Energy Technology Data Exchange (ETDEWEB)

    Chun, K J; Lee, Y K; Kim, J S; Kim, J K; Lee, S J

    2000-08-01

    To investigate the mechanisms of gene action related to the radiation resistance in microorganisms could be essentially helpful for the development of radiation protectants and hormeric effects of low dose radiation. This book described isolation of radiation-resistant microorganisms, induction of radiation-resistant and functionally improved mutants by gamma-ray radiation, cloning and analysis of the radiation resistance related genes and analysis of the expressed proteins of the radiation resistant related genes.

  3. Biological improvement of radiation resistance

    International Nuclear Information System (INIS)

    Chun, K. J.; Lee, Y. K.; Kim, J. S.; Kim, J. K.; Lee, S. J.

    2000-08-01

    To investigate the mechanisms of gene action related to the radiation resistance in microorganisms could be essentially helpful for the development of radiation protectants and hormeric effects of low dose radiation. This book described isolation of radiation-resistant microorganisms, induction of radiation-resistant and functionally improved mutants by gamma-ray radiation, cloning and analysis of the radiation resistance related genes and analysis of the expressed proteins of the radiation resistant related genes

  4. Biotechnology: herbicide-resistant crops

    Science.gov (United States)

    Transgenic, herbicide-resistant (HR) crops are planted on about 80% of the land covered by transgenic crops. More than 90% of HR crios are glyphosate-resistant (GR) crops, the others being resistant to glufosinate. The wide-scale adoption of HR crops, largely for economic reasons, has been the mos...

  5. Resistance in Everyday Life

    DEFF Research Database (Denmark)

    This book is about resistance in everyday life, illustrated through empirical contexts from different parts of the world. Resistance is a widespread phenomenon in biological, social and psychological domains of human cultural development. Yet, it is not well articulated in the academic literature....... The contributors deal with strategies for handling dissent by individuals or groups, specifically dissent through resistance. Resistance can be a location of intense personal, interpersonal and cultural negotiation, and that is the primary reason for interest in this phenomenon. Ordinary life events contain...

  6. Resistent tuberkulose i Danmark

    DEFF Research Database (Denmark)

    Thomsen, V O; Johansen, I S; Bauer, J O

    2001-01-01

    INTRODUCTION: Increased rates of multidrug-resistant (MDR) tuberculosis (TB) has been reported from countries close to Denmark. We evaluated the incidence of drug resistance in Denmark in order to determine the magnitude of the problem. MATERIALS AND METHODS: Susceptibility testing was performed......-cluster. Among all patients with isoniazid- and streptomycin-resistance, 77.0% had clustered strains. DISCUSSION: In conclusion, although drug resistance among untreated Danes was close to the rate estimated in good national programmes, close monitoring is needed in future years, as active transmission...

  7. Drug resistance in Mexico: results from the National Survey on Drug-Resistant Tuberculosis.

    Science.gov (United States)

    Bojorquez-Chapela, I; Bäcker, C E; Orejel, I; López, A; Díaz-Quiñonez, A; Hernández-Serrato, M I; Balandrano, S; Romero, M; Téllez-Rojo Solís, M M; Castellanos, M; Alpuche, C; Hernández-Ávila, M; López-Gatell, H

    2013-04-01

    To present estimations obtained from a population-level survey conducted in Mexico of prevalence rates of mono-, poly- and multidrug-resistant strains among newly diagnosed cases of pulmonary tuberculosis (TB), as well as the main factors associated with multidrug resistance (combined resistance to isoniazid and rifampicin). Study data came from the National Survey on TB Drug Resistance (ENTB-2008), a nationally representative survey conducted during 2008-2009 in nine states with a stratified cluster sampling design. Samples were obtained for all newly diagnosed cases of pulmonary TB in selected sites. Drug susceptibility testing (DST) was performed for anti-tuberculosis drugs. DST results were obtained for 75% of the cases. Of these, 82.2% (95%CI 79.5-84.7) were susceptible to all drugs. The prevalence of multidrug-resistant TB (MDR-TB) was estimated at 2.8% (95%CI 1.9-4.0). MDR-TB was associated with previous treatment (OR 3.3, 95%CI 1.1-9.4). The prevalence of drug resistance is relatively low in Mexico. ENTB-2008 can be used as a baseline for future follow-up of drug resistance.

  8. Resistência de plantas daninhas aos herbicidas Weed resistance to herbicides

    Directory of Open Access Journals (Sweden)

    Pedro J. Christoffoleti

    1994-01-01

    Full Text Available A resistência de plantas daninhas aos herbicidas ocorre em função de um processo evolutivo. O desenvolvimento de biótipos de plantas daninhas resistentes é imposto pela agricultura moderna, através da pressão de seleção causada pelo uso intensivo dos herbicidas. O conhecimento dos mecanismos e fatores que favorecem o aparecimento de biótipos de plantas daninhas resistentes é fundamental para que técnicas de manejo sejam utilizadas no sentido de evitar ou retardar o aparecimento de plantas resistentes em uma área. São poucos os relatos ou citações de literatura no Brasil. Sendo assim, este trabalho de revisão procura relatar os principais avanços e descobertas na área de plantas daninhas resistentes aos herbicidas.Weed herbicide resistance has evolved from weed evolution. The modern agriculture is responsible for this evolution because of the intensive use of herbicides. The knowledge of mechanisms and factors that influence the weed herbicide resistance play an important role in the weed manegement techniques used to avoid or delay herbicide resistance appearence. There are not many report or scientific papers about herbi cide resistance in Brasil. Therefore, this literature review aims to provide information about the main advances and discoveries in the field of weed herbicide resistance.

  9. Heat resistant/radiation resistant cable and incore structure test device for FBR type reactor

    International Nuclear Information System (INIS)

    Tanimoto, Hajime; Shiono, Takeo; Sato, Yoshimi; Ito, Kazumi; Sudo, Shigeaki; Saito, Shin-ichi; Mitsui, Hisayasu.

    1995-01-01

    A heat resistant/radiation resistant coaxial cable of the present invention comprises an insulation layer, an outer conductor and a protection cover in this order on an inner conductor, in which the insulation layer comprises thermoplastic polyimide. In the same manner, a heat resistant/radiation resistant power cable has an insulation layer comprising thermoplastic polyimide on a conductor, and is provided with a protection cover comprising braid of alamide fibers at the outer circumference of the insulation layer. An incore structure test device for an FBR type reactor comprises the heat resistant/radiation resistant coaxial cable and/or the power cable. The thermoplastic polyimide can be extrusion molded, and has excellent radiation resistant by the extrusion, as well as has high dielectric withstand voltage, good flexibility and electric characteristics at high temperature. The incore structure test device for the FBR type reactor of the present invention comprising such a cable has excellent reliability and durability. (T.M.)

  10. Antimicrobial (Drug) Resistance

    Science.gov (United States)

    ... with facebook share with twitter share with linkedin Antimicrobial (Drug) Resistance Go to Information for Researchers ► Credit: ... and infectious diseases. Why Is the Study of Antimicrobial (Drug) Resistance a Priority for NIAID? Over time, ...

  11. Resistance seam welding

    International Nuclear Information System (INIS)

    Schueler, A.W.

    1977-01-01

    The advantages and disadvantages of the resistance seam welding process are presented. Types of seam welds, types of seam welding machines, seam welding power supplies, resistance seam welding parameters and seam welding characteristics of various metals

  12. Predicting resistance by mutagenesis: lessons from 45 years of MBC resistance

    Directory of Open Access Journals (Sweden)

    Nichola J. Hawkins

    2016-11-01

    Full Text Available When a new fungicide class is introduced, it is useful to anticipate the resistance risk in advance, attempting to predict both risk level and potential mechanisms. One tool for the prediction of resistance risk is laboratory selection for resistance, with the mutational supply increased through UV or chemical mutagenesis. This enables resistance to emerge more rapidly than in the field, but may produce mutations that would not emerge under field conditions.The methyl-benzimidazole carbamates (MBCs were the first systemic single-site agricultural fungicides, and the first fungicides affected by rapid evolution of target-site resistance. MBC resistance has now been reported in over 90 plant pathogens in the field, and laboratory mutants have been studied in nearly 30 species.The most common field mutations, including β-tubulin E198A/K/G, F200Y and L240F, have all been identified in laboratory mutants. However, of 28 mutations identified in laboratory mutants, only nine have been reported in the field. Therefore, the predictive value of mutagenesis studies would be increased by understanding which mutations are likely to emerge in the field.Our review of the literature indicates that mutations with high resistance factors, and those found in multiple species, are more likely to be reported in the field. However, there are many exceptions, possibly due to fitness penalties. Whether a mutation occurred in the same species appears less relevant, perhaps because β-tubulin is highly conserved so functional constraints are similar across all species. Predictability of mutations in other target sites will depend on the level and conservation of constraints.

  13. Changing prevalence and resistance patterns in children with drug-resistant tuberculosis in Mumbai.

    Science.gov (United States)

    Shah, Ira; Shah, Forum

    2017-05-01

    The prevalence of drug-resistant (DR) tuberculosis (TB) in children is increasing. Although, in India, multi-drug-resistant (MDR) TB rates have been relatively stable, the number of children with pre-extensively drug-resistant and extensively drug-resistant (XDR) TB is increasing. To determine whether the prevalence of DR TB in children in Mumbai is changing and to study the evolving patterns of resistance. A retrospective study was undertaken in 1311 paediatric patients referred between April 2007 and March 2013 to the Paediatric TB clinic at B. J. Wadia Hospital for Children, Mumbai. Children were defined as having DR TB on the basis of drug susceptibility testing (DST) of Mycobacterium tuberculosis grown on culture of body fluids (in the case of extra pulmonary TB) or from gastric lavage/bronchi-alveolar lavage/sputum in patients with pulmonary TB or from DST of the contacts. The prevalence of DR TB was calculated and the type of DR was evaluated yearly and in the pre-2010 and post-2010 eras. The overall prevalence of DR TB was 86 (6.6%) with an increase from 23 (5.6%) patients pre-2010 to 63 (7%) post-2010 (P = 0.40). Nine (10.4%) patients were diagnosed on the basis of contact with a parent with DR TB. Overall fluoroquinolone resistance increased from 9 (39.1%) pre-2010 to 59 (93.7%) post-2010 (P = 0.0001): moxifloxacin resistance increased from 2 (8.7%) to 29 (46%) (P = 0.0018) and ofloxacin resistance increased from 7 (30.4%) to 30 (47.6%) (P = 0.14). Ethionamide resistance also increased from 6 (26.1%) to 31 (49.2%) (P = 0.04), aminoglycoside resistance was one (4.3%) pre-2010 and 12 (19%) post-2010 (P = 0.17) and resistance remained virtually the same for both amikacin [0 pre-2010 and 6 (9.5%) after 2010] and kanamycin [one (4.3%) pre- and 6 (9.5%) post-2010]. Of the first-line drugs, resistance remained the same for isoniazid [23 (100%) to 61 (96.8%)], rifampicin [22 (95.7%) to 51 (80.9%),P = 0.17], pyrazinamide [15 (65.2%) to

  14. Quantitative genetic tools for insecticide resistance risk assessment: estimating the heritability of resistance

    Science.gov (United States)

    Michael J. Firko; Jane Leslie Hayes

    1990-01-01

    Quantitative genetic studies of resistance can provide estimates of genetic parameters not available with other types of genetic analyses. Three methods are discussed for estimating the amount of additive genetic variation in resistance to individual insecticides and subsequent estimation of heritability (h2) of resistance. Sibling analysis and...

  15. Resistance patterns among multidrug-resistant tuberculosis patients in greater metropolitan Mumbai: trends over time.

    Science.gov (United States)

    Dalal, Alpa; Pawaskar, Akshay; Das, Mrinalini; Desai, Ranjan; Prabhudesai, Pralhad; Chhajed, Prashant; Rajan, Sujeet; Reddy, Deepesh; Babu, Sajit; Jayalakshmi, T K; Saranchuk, Peter; Rodrigues, Camilla; Isaakidis, Petros

    2015-01-01

    While the high burden of multidrug-resistant tuberculosis (MDR-TB) itself is a matter of great concern, the emergence and rise of advanced forms of drug-resistance such as extensively drug-resistant TB (XDR-TB) and extremely drug-resistant TB (XXDR-TB) is more troubling. The aim of this study was to investigate the trends over time of patterns of drug resistance in a sample of MDR-TB patients in greater metropolitan Mumbai, India. This was a retrospective, observational study of drug susceptibility testing (DST) results among MDR-TB patients from eight health care facilities in greater Mumbai between 2005 and 2013. We classified resistance patterns into four categories: MDR-TB, pre-XDR-TB, XDR-TB and XXDR-TB. A total of 340 MDR-TB patients were included in the study. Pre-XDR-TB was the most common form of drug-resistant TB observed overall in this Mumbai population at 56.8% compared to 29.4% for MDR-TB. The proportion of patients with MDR-TB was 39.4% in the period 2005-2007 and 27.8% in 2011-2013, while the proportion of those with XDR-TB and XXDR-TB was changed from 6.1% and 0% respectively to 10.6% and 5.6% during the same time period. During the same periods, the proportions of patients with ofloxacin, moxifloxacin and ethionamide resistance significantly increased from 57.6% to 75.3%, from 60.0% to 69.5% and from 24.2% to 52.5% respectively (pMumbai highlight the need for individualized drug regimens, designed on the basis of DST results involving first- and second-line anti-TB drugs and treatment history of the patient. A drug-resistant TB case-finding strategy based on molecular techniques that identify only rifampicin resistance will lead to initiation of suboptimal treatment regimens for a significant number of patients, which may in turn contribute to amplification of resistance and transmission of strains with increasingly advanced resistance within the community.

  16. Vancomycin Resistance in Staphylococcus aureus


    Science.gov (United States)

    McGuinness, Will A.; Malachowa, Natalia; DeLeo, Frank R.

    2017-01-01

    The evolution of Staphylococcus aureus during the modern antibiotic era has been delineated by distinct strain emergence events, many of which include acquisition of antibiotic resistance. The relative high burden of methicillin-resistant S. aureus (MRSA) in healthcare and community settings is a major concern worldwide. Vancomycin, a glycopeptide antibiotic that inhibits cell wall biosynthesis, remains a drug of choice for treatment of severe MRSA infections. S. aureus strains exhibiting increased resistance to vancomycin, known as vancomycin intermediate-resistant S. aureus (VISA) (MIC = 4-8 µg/mL), were discovered in the 1990s. The molecular basis of resistance in VISA is polygenic and involves stepwise mutations in genes encoding molecules predominantly involved in cell envelope biosynthesis. S. aureus isolates with complete resistance to vancomycin (MIC ≥ 16 µg/mL) are termed vancomycin-resistant S. aureus (VRSA)—they were first reported in the U.S. in 2002. Resistance in VRSA is conferred by the vanA gene and operon, which is present on a plasmid. Although treatment of VRSA infections is challenging, the total number of human VRSA infections to date is limited (14 in the U.S.). By comparison, the burden of VISA is relatively high and the molecular mechanisms of resistance are less well-defined. VISA are associated with persistent infections, vancomycin treatment failure, and poor clinical outcomes. Here, we review in brief progress made toward understanding the acquisition of antibiotic resistance in S. aureus, with an emphasis on the molecular mechanisms underlying vancomycin resistance. PMID:28656013

  17. Reducing Resistance

    DEFF Research Database (Denmark)

    Lindell, Johanna

    care may influence decisions on antibiotic use. Based on video-and audio recordings of physician-patient consultations it is investigated how treatment recommendations are presented, can be changed, are forecast and explained, and finally, how they seemingly meet resistance and how this resistance......Antibiotic resistance is a growing public health problem both nationally and internationally, and efficient strategies are needed to reduce unnecessary use. This dissertation presents four research studies, which examine how communication between general practitioners and patients in Danish primary...... is responded to.The first study in the dissertation suggests that treatment recommendations on antibiotics are often done in a way that encourages patient acceptance. In extension of this, the second study of the dissertation examines a case, where acceptance of such a recommendation is changed into a shared...

  18. Multidrug Resistance in Infants and Children

    Directory of Open Access Journals (Sweden)

    Gian Maria Pacifici

    2018-02-01

    Full Text Available Bacterial infections may cause disease and death. Infants and children are often subject to bacterial infections. Antimicrobials kill bacteria protecting the infected patients andreducing the risk of morbidity and mortality caused by bacteria. The antibiotics may lose their antibacterial activity when they become resistant to a bacteria. The resistance to different antibiotics in a bacteria is named multidrug-resistance. Gram-negative bacilli, especially Escherichia coli, Klebsiella, Enterobacter, Salmonella, Shigella, Pseudomonas, Streptococcus, and Haemophilus influenzae type b, may become resistant. Amikacin ampicillin, amoxicillin, amoxiclav, cefuroxime, cefotaxime, ceftazidime, cefoperazone tetracycline, chloramphenicol, ciprofloxacin, and gentamicin may cause bacterial-resistance. Resistance to bacteria for several pathogens makes complications in the treatment of infections caused by them. Salmonella strains may become resistant to ampicillin, cephalotin, ceftriaxone, gentamicin, amikacin, trimethoprim-sulfamethoxazole, chloramphenicol, and tetracycline. Shigella strains may become resistant to ampicillin, cotrimoxazole, chloramphenicol, and streptomycin. Multidrug-resistance of Streptococcus pneumoniae may be due to β-lactams, macrolides, tetracycline, chloramphenicol, and trimethoprim-sulfamethoxazole. Multidrug-resistance of Pseudomonas aeruginosa may become resistant to β-lactams, chloramphenicol, trimethoprim-sulfamethoxazole, and tetracycline. The antibacterial activity against Haemophilus strains may occur with ampicillin, sulbactam-ampicillin, trimethoprim-sulfamethoxazole, gentamicin, chloramphenicol, and ciprofloxacin. Multidrug-resistance of the Klebsiella species may be due with ampicillin, cefotaxime, cefuroxime, co-amxilav, mezlocillin, chloramphenicol, gentamicin, and ceftazidime. Multidrug-resistance of Escherichia coli may be caused by ampicillin, cotrimoxazole, chloramphenicol, ceftriaxone, and ceftazidime. Vibrio

  19. Triazole resistance surveillance in Aspergillus fumigatus.

    Science.gov (United States)

    Resendiz Sharpe, Agustin; Lagrou, Katrien; Meis, Jacques F; Chowdhary, Anuradha; Lockhart, Shawn R; Verweij, Paul E

    2018-04-01

    Triazole resistance is an increasing concern in the opportunistic mold Aspergillus fumigatus. Resistance can develop through exposure to azole compounds during azole therapy or in the environment. Resistance mutations are commonly found in the Cyp51A-gene, although other known and unknown resistance mechanisms may be present. Surveillance studies show triazole resistance in six continents, although the presence of resistance remains unknown in many countries. In most countries, resistance mutations associated with the environment dominate, but it remains unclear if these resistance traits predominately migrate or arise locally. Patients with triazole-resistant aspergillus disease may fail to antifungal therapy, but only a limited number of cohort studies have been performed that show conflicting results. Treatment failure might be due to diagnostic delay or due to the limited number of alternative treatment options. The ISHAM/ECMM Aspergillus Resistance Surveillance working group was set up to facilitate surveillance studies and stimulate international collaborations. Important aims are to determine the resistance epidemiology in countries where this information is currently lacking, to gain more insight in the clinical implications of triazole resistance through a registry and to unify nomenclature through consensus definitions.

  20. Prevalence of plasmid-mediated quinolone resistance determinants among oxyiminocephalosporin-resistant Enterobacteriaceae in Argentina

    Directory of Open Access Journals (Sweden)

    Giovanna Rincon Cruz

    2013-11-01

    Full Text Available High quinolone resistance rates were observed among oxyiminocephalosporin-resistant enterobacteria. In the present study, we searched for the prevalence of plasmid-mediated quinolone resistance (PMQR genes within the 55 oxyiminocephalosporin-resistant enterobacteria collected in a previous survey. The main PMQR determinants were aac(6'-Ib-cr and qnrB, which had prevalence rates of 42.4% and 33.3%, respectively. The aac(6'-Ib-cr gene was more frequently found in CTX-M-15-producing isolates, while qnrB was homogeneously distributed among all CTX-M producers.

  1. Whole genome analysis of linezolid resistance in Streptococcus pneumoniae reveals resistance and compensatory mutations

    Directory of Open Access Journals (Sweden)

    Légaré Danielle

    2011-10-01

    Full Text Available Abstract Background Several mutations were present in the genome of Streptococcus pneumoniae linezolid-resistant strains but the role of several of these mutations had not been experimentally tested. To analyze the role of these mutations, we reconstituted resistance by serial whole genome transformation of a novel resistant isolate into two strains with sensitive background. We sequenced the parent mutant and two independent transformants exhibiting similar minimum inhibitory concentration to linezolid. Results Comparative genomic analyses revealed that transformants acquired G2576T transversions in every gene copy of 23S rRNA and that the number of altered copies correlated with the level of linezolid resistance and cross-resistance to florfenicol and chloramphenicol. One of the transformants also acquired a mutation present in the parent mutant leading to the overexpression of an ABC transporter (spr1021. The acquisition of these mutations conferred a fitness cost however, which was further enhanced by the acquisition of a mutation in a RNA methyltransferase implicated in resistance. Interestingly, the fitness of the transformants could be restored in part by the acquisition of altered copies of the L3 and L16 ribosomal proteins and by mutations leading to the overexpression of the spr1887 ABC transporter that were present in the original linezolid-resistant mutant. Conclusions Our results demonstrate the usefulness of whole genome approaches at detecting major determinants of resistance as well as compensatory mutations that alleviate the fitness cost associated with resistance.

  2. The perspectives of polygenic resistance in breeding for durable disease resistance

    NARCIS (Netherlands)

    Lindhout, P.

    2002-01-01

    Polygenic resistance is generally quantitative without clear race specific effects. With the onset of molecular markers technologies, the identification of chromosome regions that are involved in quantitative resistance has become feasible. These regions are designated quantitative trait loci

  3. Response of wild and weedy broomrapes to synthetic strigolactone analogue GR24

    Directory of Open Access Journals (Sweden)

    Radoslava Matusova

    2014-12-01

    Full Text Available Parasitic plants of genera Orobanche and Phelipanche germinate after exposition to chemical signals exuded by roots of the host plants. The most studied germination stimulants belong to strigolactones (SLs, the newly discovered plant hormones which are stimulating hyphal branching of arbuscular mycorrhizal fungi and are involved in regulation of shoot and root architecture of plants. However, little is known about the effect of strigolactones on germination of non-weedy broomrapes. The objective of our study was to investigate the sensitivity of seeds of non-weedy broomrapes to synthetic analogue of SLs, GR24. The seeds of non-weedy broomrapes Orobanche alba, O. alsatica, O. caryophyllacea, O. elatior, O. flava, O. lutea, O. pallidiflora, O. reticulata, Phelipanche arenaria, P. purpurea and weedy species P. ramosa were collected in natural and cropland plant communities in Slovakia. Seeds of P. ramosa and P. purpurea were highly sensitive to GR24. On the other hand, effectivity of GR24 in inducing germination of several wild species, O. alba, O. caryophyllacea and P. arenaria was low, while the stimulant shown to be completely not effective on other non-weedy species O. alsatica, O. elatior, O. flava, O. lutea, O. pallidiflora, and O. reticulata. The results point out there are differences in the requirement for germination signals that possibly depend on the host.

  4. Resistência de Eleusine indica aos inibidores de ACCase Eleusine indica resistance to ACCase inhibitors

    Directory of Open Access Journals (Sweden)

    R.A. Vidal

    2006-01-01

    Full Text Available Dentre as causas da ineficácia no controle de plantas daninhas destaca-se a resistência delas aos herbicidas. Os objetivos deste trabalho foram avaliar a suspeita de resistência de Eleusine indica a inibidores de acetil-CoA carboxilase (ACCase e investigar a ocorrência de resistência cruzada entre os inibidores de ACCase. Biótipo de Eleusine indica originado do Mato Grosso com suspeita de resistência aos herbicidas inibidores de ACCase foi avaliado em casa de vegetação na sua suscetibilidade para diversos produtos do grupo dos ariloxifenoxipropionatos e cicloexanodionas. Estudos de resposta à dose confirmaram que o biótipo era 18 vezes mais insensível ao sethoxydim do que biótipo suscetível nunca aspergido com herbicidas. Também se constatou resistência cruzada ao fenoxaprop, cyhalofop, propaquizafop e butroxydim. Não se observou resistência cruzada aos produtos fluazifop, haloxyfop, quizalofop e clethodim.Among the causes for weed control inefficacy, the worst one is resistance to herbicides. The objectives of this work were to evaluate an Eleusine indica biotype suspected of resistance to ACCase inhibitors and to investigate the occurrence of cross- resistance to several ACCase inhibitors. One biotype of Eleusine indica originated from Mato Grosso with suspected resistance to ACCase inhibitors was evaluated in a greenhouse in relation to its susceptibility to several products of the ariloxyphenoxypropionate and cyclohexanedione groups. Studies on dose response confirmed that the suspected biotype was 18 times more insensitive to sethoxydim than the susceptible biotype that had never been treated with herbicides. Cross-resistance was confirmed for fenoxaprop, cyhalofop, propaquizafop and butroxydim. No cross-resistance was observed with fluazifop, haloxyfop, quizalofop, and clethodim.

  5. Resistance to change

    NARCIS (Netherlands)

    Dow, J.; Perotti, E.

    2009-01-01

    Established firms often fail to maintain leadership following disruptive market shifts. We argue that such firms are more prone to internal resistance. A radical adjustment of assets affects the distribution of employee rents, creating winners and losers. Losers resist large changes when strong

  6. 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

  7. FRC collisionless resistivity

    International Nuclear Information System (INIS)

    Tajima, T.; Horton, W.

    1990-01-01

    Ions in the field reversed configuration (FRC) exhibit stochastic orbits due to the field null and the curvature of poloidal field lines. Velocity correlations of these particles decay in a power law fashion t -m where 1 ≤ m ≤ 2. This decay of the single particle correlation function is characteristic of the long tail correlations of strongly chaotic or nonlinear systems found in other problems of statistical physics. This decay of correlations gives rise to a collisionless resistivity that can far exceed the collisional resistivity in an FRC plasma. The finite correlation τ c of a single particle limits the acceleration in the electric field producing the finite resistivity. Maxwellian test particle distributions are integrated to find the measure of the set of stochastic ions that contribute to the collisionless resistivity. The computed conductivity is proportional to the square root of the characteristic ion gyroradius in both simulation and theory

  8. The Prehistory of Antibiotic Resistance.

    Science.gov (United States)

    Perry, Julie; Waglechner, Nicholas; Wright, Gerard

    2016-06-01

    Antibiotic resistance is a global problem that is reaching crisis levels. The global collection of resistance genes in clinical and environmental samples is the antibiotic "resistome," and is subject to the selective pressure of human activity. The origin of many modern resistance genes in pathogens is likely environmental bacteria, including antibiotic producing organisms that have existed for millennia. Recent work has uncovered resistance in ancient permafrost, isolated caves, and in human specimens preserved for hundreds of years. Together with bioinformatic analyses on modern-day sequences, these studies predict an ancient origin of resistance that long precedes the use of antibiotics in the clinic. Understanding the history of antibiotic resistance is important in predicting its future evolution. Copyright © 2016 Cold Spring Harbor Laboratory Press; all rights reserved.

  9. Effect of Ampicillin, Streptomycin, Penicillin and Tetracycline on Metal Resistant and Non-Resistant Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Dagmar Chudobova

    2014-03-01

    Full Text Available There is an arising and concerning issue in the field of bacterial resistance, which is confirmed by the number of deaths associated with drug-resistant bacterial infections. The aim of this study was to compare the effects of antibiotics on Staphylococcus aureus non-resistant strain and strains resistant to cadmium or lead ions. Metal resistant strains were created by the gradual addition of 2 mM solution of metal ions (cadmium or lead to the S. aureus culture. An increasing antimicrobial effect of ampicillin, streptomycin, penicillin and tetracycline (0, 10, 25, 50, 75, 150, 225 and 300 µM on the resistant strains was observed using a method of growth curves. A significant growth inhibition (compared to control of cadmium resistant cells was observed in the presence of all the four different antibiotics. On the other hand, the addition of streptomycin and ampicillin did not inhibit the growth of lead resistant strain. Other antibiotics were still toxic to the bacterial cells. Significant differences in the morphology of cell walls were indicated by changes in the cell shape. Our data show that the presence of metal ions in the urban environment may contribute to the development of bacterial strain resistance to other substances including antibiotics, which would have an impact on public health.

  10. Effect of Ampicillin, Streptomycin, Penicillin and Tetracycline on Metal Resistant and Non-Resistant Staphylococcus aureus

    Science.gov (United States)

    Chudobova, Dagmar; Dostalova, Simona; Blazkova, Iva; Michalek, Petr; Ruttkay-Nedecky, Branislav; Sklenar, Matej; Nejdl, Lukas; Kudr, Jiri; Gumulec, Jaromir; Tmejova, Katerina; Konecna, Marie; Vaculovicova, Marketa; Hynek, David; Masarik, Michal; Kynicky, Jindrich; Kizek, Rene; Adam, Vojtech

    2014-01-01

    There is an arising and concerning issue in the field of bacterial resistance, which is confirmed by the number of deaths associated with drug-resistant bacterial infections. The aim of this study was to compare the effects of antibiotics on Staphylococcus aureus non-resistant strain and strains resistant to cadmium or lead ions. Metal resistant strains were created by the gradual addition of 2 mM solution of metal ions (cadmium or lead) to the S. aureus culture. An increasing antimicrobial effect of ampicillin, streptomycin, penicillin and tetracycline (0, 10, 25, 50, 75, 150, 225 and 300 µM) on the resistant strains was observed using a method of growth curves. A significant growth inhibition (compared to control) of cadmium resistant cells was observed in the presence of all the four different antibiotics. On the other hand, the addition of streptomycin and ampicillin did not inhibit the growth of lead resistant strain. Other antibiotics were still toxic to the bacterial cells. Significant differences in the morphology of cell walls were indicated by changes in the cell shape. Our data show that the presence of metal ions in the urban environment may contribute to the development of bacterial strain resistance to other substances including antibiotics, which would have an impact on public health. PMID:24651395

  11. Herbicide resistance and biodiversity: agronomic and environmental aspects of genetically modified herbicide-resistant plants.

    Science.gov (United States)

    Schütte, Gesine; Eckerstorfer, Michael; Rastelli, Valentina; Reichenbecher, Wolfram; Restrepo-Vassalli, Sara; Ruohonen-Lehto, Marja; Saucy, Anne-Gabrielle Wuest; Mertens, Martha

    2017-01-01

    Farmland biodiversity is an important characteristic when assessing sustainability of agricultural practices and is of major international concern. Scientific data indicate that agricultural intensification and pesticide use are among the main drivers of biodiversity loss. The analysed data and experiences do not support statements that herbicide-resistant crops provide consistently better yields than conventional crops or reduce herbicide amounts. They rather show that the adoption of herbicide-resistant crops impacts agronomy, agricultural practice, and weed management and contributes to biodiversity loss in several ways: (i) many studies show that glyphosate-based herbicides, which were commonly regarded as less harmful, are toxic to a range of aquatic organisms and adversely affect the soil and intestinal microflora and plant disease resistance; the increased use of 2,4-D or dicamba, linked to new herbicide-resistant crops, causes special concerns. (ii) The adoption of herbicide-resistant crops has reduced crop rotation and favoured weed management that is solely based on the use of herbicides. (iii) Continuous herbicide resistance cropping and the intensive use of glyphosate over the last 20 years have led to the appearance of at least 34 glyphosate-resistant weed species worldwide. Although recommended for many years, farmers did not counter resistance development in weeds by integrated weed management, but continued to rely on herbicides as sole measure. Despite occurrence of widespread resistance in weeds to other herbicides, industry rather develops transgenic crops with additional herbicide resistance genes. (iv) Agricultural management based on broad-spectrum herbicides as in herbicide-resistant crops further decreases diversity and abundance of wild plants and impacts arthropod fauna and other farmland animals. Taken together, adverse impacts of herbicide-resistant crops on biodiversity, when widely adopted, should be expected and are indeed very hard

  12. Resistance to fluoroquinolones and second-line injectable drugs: impact on multidrug-resistant TB outcomes

    NARCIS (Netherlands)

    Falzon, Dennis; Gandhi, Neel; Migliori, Giovanni B.; Sotgiu, Giovanni; Cox, Helen S.; Holtz, Timothy H.; Hollm-Delgado, Maria-Graciela; Keshavjee, Salmaan; Deriemer, Kathryn; Centis, Rosella; D'Ambrosio, Lia; Lange, Christoph G.; Bauer, Melissa; Menzies, Dick; Ahuja, S. D.; Ashkin, D.; Avendaño, M.; Banerjee, R.; Bauer, M.; Becerra, M. C.; Benedetti, A.; Burgos, M.; Centis, R.; Chan, E. D.; Chiang, C. Y.; Cobelens, F.; Cox, H.; D'Ambrosio, L.; de Lange, W. C. M.; DeRiemer, K.; Enarson, D.; Falzon, D.; Flanagan, K. L.; Flood, J.; Gandhi, N.; Garcia-Garcia, M. L.; Granich, R. M.; Hollm-Delgado, M. G.; Holtz, T. H.; Hopewell, P.; Iseman, M. D.; Jarlsberg, L. G.; Keshavjee, S.; Kim, H. R.; Koh, W. J.; Lancaster, J. L.; Lange, C.; Leimane, V.; Leung, C. C.; Li, J.

    2013-01-01

    A meta-analysis for response to treatment was undertaken using individual data of multidrug-resistant tuberculosis (MDR-TB) (resistance to isoniazid and rifampicin) patients from 26 centres. The analysis assessed the impact of additional resistance to fluoroquinolones and/or second-line injectable

  13. Resistance to change

    NARCIS (Netherlands)

    Dow, J.; Perotti, E.

    2013-01-01

    Established firms often fail to maintain leadership following disrup tive market shifts. We argue that such firms are more prone to internal resistance. A radical adjustment of assets affects the distribution of employee rents, creating winners and losers. Losers resist large changes when strong

  14. Antimicrobial resistance and resistance gene determinants in clinical Escherichia coli from different animal species in Switzerland.

    Science.gov (United States)

    Lanz, Roland; Kuhnert, Peter; Boerlin, Patrick

    2003-01-02

    Antimicrobial susceptibility testing was performed on a total of 581 clinical Escherichia coli isolates from diarrhea and edema disease in pigs, from acute mastitis in dairy cattle, from urinary tract infections in dogs and cats, and from septicemia in laying hens collected in Switzerland between 1999 and 2001. Among the 16 antimicrobial agents tested, resistance was most frequent for sulfonamides, tetracycline, and streptomycin. Isolates from swine presented significantly more resistance than those from the other animal species. The distribution of the resistance determinants for sulfonamides, tetracycline, and streptomycin was assessed by hybridization and PCR in resistant isolates. Significant differences in the distribution of resistance determinants for tetracycline (tetA, tetB) and sulfonamides (sulII) were observed between the isolates from swine and those from the other species. Resistance to sulfonamides could not be explained by known resistance mechanisms in more than a quarter of the sulfonamide-resistant and sulfonamide-intermediate isolates from swine, dogs and cats. This finding suggests that one or several new resistance mechanisms for sulfonamides may be widespread among E. coli isolates from these animal species. The integrase gene (intI) from class I integrons was detected in a large proportion of resistant isolates in association with the sulI and aadA genes, thus demonstrating the importance of integrons in the epidemiology of resistance in clinical E. coli isolates from animals.

  15. Are Sewage Treatment Plants Promoting Antibiotic Resistance?

    Science.gov (United States)

    1. Introduction 1.1. How bacteria exhibit resistance 1.1.1. Resistance to -lactams 1.1.2. Resistance to sulphonamides and trimethoprim 1.1.3. Resistance to macrolides 1.1.4. Resistance to fluoroquinolones 1.1.5. Resistance to tetracyclines 1.1.6. Resistance to nitroimidaz...

  16. Ceftaroline-Resistant, Daptomycin-Tolerant, and Heterogeneous Vancomycin-Intermediate Methicillin-Resistant Staphylococcus aureus Causing Infective Endocarditis.

    Science.gov (United States)

    Nigo, Masayuki; Diaz, Lorena; Carvajal, Lina P; Tran, Truc T; Rios, Rafael; Panesso, Diana; Garavito, Juan D; Miller, William R; Wanger, Audrey; Weinstock, George; Munita, Jose M; Arias, Cesar A; Chambers, Henry F

    2017-03-01

    We report a case of infective endocarditis (IE) caused by ceftaroline-resistant, daptomycin-tolerant, and heterogeneous vancomycin-intermediate methicillin-resistant S. aureus (MRSA). Resistance to ceftaroline emerged in the absence of drug exposure, and the E447K substitution in the active site of PBP2a previously associated with ceftaroline resistance was identified. Additionally, we present evidence of patient-to-patient transmission of the strain within the same unit. This case illustrates the difficulties in treating MRSA IE in the setting of a multidrug-resistant phenotype. Copyright © 2017 American Society for Microbiology.

  17. Antimicrobial resistance and prevalence of resistance genes of obligate anaerobes isolated from periodontal abscesses.

    Science.gov (United States)

    Xie, Yi; Chen, Jiazhen; He, Junlin; Miao, Xinyu; Xu, Meng; Wu, Xingwen; Xu, Beiyun; Yu, Liying; Zhang, Wenhong

    2014-02-01

    This study attempts to determine the antimicrobial resistance profiles of obligate anaerobic bacteria that were isolated from a periodontal abscess and to evaluate the prevalence of resistance genes in these bacteria. Forty-one periodontal abscess samples were cultivated on selective and non-selective culture media to isolate the oral anaerobes. Their antibiotic susceptibilities to clindamycin, doxycycline, amoxicillin, imipenem, cefradine, cefixime, roxithromycin, and metronidazole were determined using the agar dilution method, and polymerase chain reaction assays were performed to detect the presence of the ermF, tetQ, nim, and cfxA drug resistance genes. A total of 60 different bacterial colonies was isolated and identified. All of the isolates were sensitive to imipenem. Of the strains, 6.7%, 13.3%, 16.7%, and 25% were resistant to doxycycline, metronidazole, cefixime, and amoxicillin, respectively. The resistance rate for both clindamycin and roxithromycin was 31.7%. Approximately 60.7% of the strains had the ermF gene, and 53.3% of the amoxicillin-resistant strains were found to have the cfxA gene. Two nim genes that were found in eight metronidazole-resistant strains were identified as nimB. In the present study, the Prevotella species are the most frequently isolated obligate anaerobes from periodontal abscesses. The current results show their alarmingly high resistance rate against clindamycin and roxithromycin; thus, the use of these antibiotics is unacceptable for the empirical therapy of periodontal abscesses. A brief prevalence of four resistance genes in the anaerobic bacteria that were isolated was also demonstrated.

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

    Science.gov (United States)

    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.

  19. Animation of Antimicrobial Resistance

    Science.gov (United States)

    ... Animal & Veterinary Cosmetics Tobacco Products Animal & Veterinary Home Animal & Veterinary Safety & Health Antimicrobial Resistance Animation of Antimicrobial Resistance Share Tweet Linkedin Pin ...

  20. Antibiotic resistance and resistance genes in Escherichia coli from poultry farms, southwest Nigeria.

    Science.gov (United States)

    Adelowo, Olawale O; Fagade, Obasola E; Agersø, Yvonne

    2014-09-12

    This study investigated the mechanisms of resistance in 36 E. coli isolated from waste, litter, soil and water samples collected from poultry farms in Southwestern Nigeria. Minimum inhibitory concentration (MIC) distributions of the isolates were determined using the methods of the Clinical and Laboratory Standard Institute and resistance genes detected by PCR. A total of 30 isolates (94%) showed resistance to more than one antimicrobial. Percentage resistance was: tetracycline 81%, sulphamethoxazole 67%, streptomycin 56%, trimethoprim 47 %, ciprofloxacin 42%, ampicillin 36%, spectinomycin 28%, nalidixic acid 25%, chloramphenicol 22%, neomycin 14%, gentamicin 8%, amoxicillin-clavulanate, ceftiofur, cefotaxime, colistin, florfenicol and apramycin 0%. Resistance genes found among the isolates include bla-TEM (85%), sul2 (67%), sul3 (17%), aadA (65%), strA (70%), strB (61%), catA1 (25%), cmlA1 (13%), tetA (21%) and tetB (17%). Class 1 and 2 integrons were found in five (14%) and six (17%) isolates, respectively, while one isolate was positive for both classes of integrons. Seven out of eight isolates with resistance to ciprofloxacin and MIC ≤ 32 mg/L to nalidixic acid contained qnrS genes. Our findings provided additional evidence that the poultry production environment in Nigeria represents an important reservoir of antibiotic resistance genes such as qnrS that may spread from livestock production farms to human populations via manure and water.

  1. Observations on resistive wall modes

    International Nuclear Information System (INIS)

    Gerwin, R.A.; Finn, J.M.

    1996-01-01

    Several results on resistive wall modes and their application to tokamaks are presented. First, it is observed that in the presence of collisional parallel dynamics there is an exact cancellation to lowest order of the dissipative and sound wave effects for an ideal Ohm's law. This is easily traced to the fact that the parallel dynamics occurs along the perturbed magnetic field lines for such electromagnetic modes. Such a cancellation does not occur in the resistive layer of a tearing-like mode. The relevance to models for resistive wall modes using an electrostatic Hammett-Perkins type operator to model Landau damping will be discussed. Second, we observe that with an ideal Ohm's law, resistive wall modes can be destabilized by rotation in that part of parameter space in which the ideal MHD modes are stable with the wall at infinity. This effect can easily be explained by interpreting the resistive wall instability in terms of mode coupling between the backward stable MHD mode and a stable mode locked into the wall. Such an effect can occur for very small rotation for tearing-resistive wall modes in which inertia dominates viscosity in the layer, but the mode is stabilized by further rotation. For modes for which viscosity dominates in the layer, rotation is purely stabilizing. For both tearing models, a somewhat higher rotation frequency gives stability essentially whenever the tearing mode is stable with a perfectly conducting wall. These tearing/resistive wall results axe also simply explained in terms of mode coupling. It has been shown that resonant external ideal modes can be stabilized in the presence of resistive wall and resistive plasma with rotation of order the nominal tearing mode growth rate. We show that these modes behave as resistive wall tearing modes in the sense above. This strengthens the suggestion that rotational stabilization of the external kink with a resistive wall is due to the presence of resistive layers, even for ideal modes

  2. Resist Parameter Extraction from Line-and-Space Patterns of Chemically Amplified Resist for Extreme Ultraviolet Lithography

    Science.gov (United States)

    Kozawa, Takahiro; Oizumi, Hiroaki; Itani, Toshiro; Tagawa, Seiichi

    2010-11-01

    The development of extreme ultraviolet (EUV) lithography has progressed owing to worldwide effort. As the development status of EUV lithography approaches the requirements for the high-volume production of semiconductor devices with a minimum line width of 22 nm, the extraction of resist parameters becomes increasingly important from the viewpoints of the accurate evaluation of resist materials for resist screening and the accurate process simulation for process and mask designs. In this study, we demonstrated that resist parameters (namely, quencher concentration, acid diffusion constant, proportionality constant of line edge roughness, and dissolution point) can be extracted from the scanning electron microscopy (SEM) images of patterned resists without the knowledge on the details of resist contents using two types of latest EUV resist.

  3. Genetics Home Reference: clopidogrel resistance

    Science.gov (United States)

    ... Facebook Twitter Home Health Conditions Clopidogrel resistance Clopidogrel resistance Printable PDF Open All Close All Enable Javascript to view the expand/collapse boxes. Description Clopidogrel resistance is a condition in which the drug clopidogrel ...

  4. Genetics Home Reference: warfarin resistance

    Science.gov (United States)

    ... Email Facebook Twitter Home Health Conditions Warfarin resistance Warfarin resistance Printable PDF Open All Close All Enable Javascript to view the expand/collapse boxes. Description Warfarin resistance is a condition in which individuals have ...

  5. Resistance and conformity

    NARCIS (Netherlands)

    Sumter, S.R.; Bokhorst, C.L.; Westenberg, P.M.; Levesque, R.J.R.

    2011-01-01

    Resistance to peer influence, or the ability to resist making choices or adopting views under the implicit or explicit influence of your peers, is expected to undergo changes during adolescence. Two developmental trajectories have emerged from the field. On the one hand, adolescents show a temporary

  6. [Molecular characterization of resistance mechanisms: methicillin resistance Staphylococcus aureus, extended spectrum β-lactamases and carbapenemases].

    Science.gov (United States)

    Oteo, Jesús; Belén Aracil, María

    2015-07-01

    Multi-drug resistance in bacterial pathogens increases morbidity and mortality in infected patients and it is a threat to public health concern by their high capacity to spread. For both reasons, the rapid detection of multi-drug resistant bacteria is critical. Standard microbiological procedures require 48-72 h to provide the antimicrobial susceptibility results, thus there is emerging interest in the development of rapid detection techniques. In recent years, the use of selective and differential culture-based methods has widely spread. However, the capacity for detecting antibiotic resistance genes and their low turnaround times has made molecular methods a reference for diagnosis of multidrug resistance. This review focusses on the molecular methods for detecting some mechanisms of antibiotic resistance with a high clinical and epidemiological impact: a) Enzymatic resistance to broad spectrum β-lactam antibiotics in Enterobacteriaceae, mainly extended spectrum β-lactamases (ESBL) and carbapenemases; and b) methicillin resistance in Staphylococcus aureus. Copyright © 2015 Elsevier España, S.L.U. All rights reserved.

  7. Piggyback resistive Micromegas

    CERN Document Server

    Attié, D; Durand, D; Desforge, D; Ferrer-Ribas, E; Galán, J; Giomataris, Y; Gongadze, A; Iguaz, F J; Jeanneau, F; de Oliveira, R; Papaevangelou, T; Peyaud, A; Teixeira, A

    2013-01-01

    Piggyback Micromegas consists in a novel readout architecture where the anode element is made of a resistive layer on a ceramic substrate. The resistive layer is deposited on the thin ceramic substrate by an industrial process which provides large dynamic range of resistivity (10$^6$ to 10$^{10}$\\,M$\\Omega$/square). The particularity of this new structure is that the active part is entirely dissociated from the read-out element. This gives a large flexibility on the design of the anode structure and the readout scheme. Without significant loss, signals are transmitted by capacitive coupling to the read-out pads. The detector provides high gas gain, good energy resolution and the resistive layer assures spark protection for the electronics. This assembly could be combined with modern pixel array electronic ASICs. First tests with different Piggyback detectors and configurations will be presented. This structure is adequate for cost effective fabrication and low outgassing detectors. It was designed to perform ...

  8. Effect of physiological age on radiation resistance of some bacteria that are highly radiation resistant

    International Nuclear Information System (INIS)

    Keller, L.C.; Maxcy, R.B.

    1984-01-01

    Physiological age-dependent variation in radiation resistance was studied for three bacteria that are highly radiation resistant: Micrococcus radiodurans, Micrococcus sp. isolate C-3, and Moraxella sp. isolate 4. Stationary-phase cultures of M. radiodurans and isolate C-3 were much more resistant to gamma radiation than were log-phase cultures. This pattern of relative resistance was reversed for isolate 4. Resistance of isolate 4 to UV light was also greater during log phase, although heat resistance and NaCl tolerance after heat stresses were greater during stationary phase. Radiation-induced injury of isolate 4 compared with injury of Escherichia coli B suggested that the injury process, as well as the lethal process, was affected by growth phase. The hypothesis that growth rate affects radiation resistance was tested, and results were interpreted in light of the probable confounding effect of methods used to alter growth rates of bacteria. These results indicate that dose-response experiments should be designed to measure survival during the most resistant growth phase of the organism under study. The timing is particularly important when extrapolations of survival results might be made to potential irradiation processes for foods. 17 references

  9. Multidrug resistance in tumour cells: characterisation of the multidrug resistant cell line K562-Lucena 1

    Directory of Open Access Journals (Sweden)

    VIVIAN M. RUMJANEK

    2001-03-01

    Full Text Available Multidrug resistance to chemotherapy is a major obstacle in the treatment of cancer patients. The best characterised mechanism responsible for multidrug resistance involves the expression of the MDR-1 gene product, P-glycoprotein. However, the resistance process is multifactorial. Studies of multidrug resistance mechanisms have relied on the analysis of cancer cell lines that have been selected and present cross-reactivity to a broad range of anticancer agents. This work characterises a multidrug resistant cell line, originally selected for resistance to the Vinca alkaloid vincristine and derived from the human erythroleukaemia cell K562. This cell line, named Lucena 1, overexpresses P-glycoprotein and have its resistance reversed by the chemosensitisers verapamil, trifluoperazine and cyclosporins A, D and G. Furthermore, we demonstrated that methylene blue was capable of partially reversing the resistance in this cell line. On the contrary, the use of 5-fluorouracil increased the resistance of Lucena 1. In addition to chemotherapics, Lucena 1 cells were resistant to ultraviolet A radiation and hydrogen peroxide and failed to mobilise intracellular calcium when thapsigargin was used. Changes in the cytoskeleton of this cell line were also observed.A resistência a múltiplos fármacos é o principal obstáculo no tratamento de pacientes com câncer. O mecanismo responsável pela resistência múltipla mais bem caracterizado envolve a expressão do produto do gene MDR-1, a glicoproteína P. Entretanto, o processo de resistência tem fatores múltiplos. Estudos de mecanismos de resistência m��ltipla a fármacos têm dependido da análise de linhagens celulares tumorais que foram selecionadas e apresentam reatividade cruzada a uma ampla faixa de agentes anti-tumorais. Este trabalho caracteriza uma linhagem celular com múltipla resistência a fármacos, selecionada originalmente pela resistência ao alcalóide de Vinca vincristina e derivado

  10. Subgroup and resistance analyses of raltegravir for resistant HIV-1 infection

    DEFF Research Database (Denmark)

    Cooper, David A; Steigbigel, Roy T; Gatell, Jose M

    2008-01-01

    BACKGROUND: We evaluated the efficacy of raltegravir and the development of viral resistance in two identical trials involving patients who were infected with human immunodeficiency virus type 1 (HIV-1) with triple-class drug resistance and in whom antiretroviral therapy had failed. METHODS: We c...

  11. Occurrence and Distribution of Antibiotic-resistant Bacteria and Transfer of Resistance Genes in Lake Taihu

    Science.gov (United States)

    Yin, Qian; Yue, Dongmei; Peng, Yuke; Liu, Ying; Xiao, Lin

    2013-01-01

    The overuse of antibiotics has accelerated antibiotic resistance in the natural environment, especially fresh water, generating a potential risk for public health around the world. In this study, antibiotic resistance in Lake Taihu was investigated and this was the first thorough data obtained through culture-dependent methods. High percentages of resistance to streptomycin and ampicillin among bacterial isolates were detected, followed by tetracycline and chloramphenicol. Especially high levels of ampicillin resistance in the western and northern regions were illustrated. Bacterial identification of the isolates selected for further study indicated the prevalence of some opportunistic pathogens and 62.0% of the 78 isolates exhibited multiple antibiotic resistance. The presence of ESBLs genes was in the following sequence: blaTEM > blaSHV > blaCTMX and 38.5% of the isolates had a class I integrase gene. Of all tested strains, 80.8% were able to transfer antibiotic resistance through conjugation. We also concluded that some new families of human-associated ESBLs and AmpC genes can be found in natural environmental isolates. The prevalence of antibiotic resistance and the dissemination of transferable antibiotic resistance in bacterial isolates (especially in opportunistic pathogens) was alarming and clearly indicated the urgency of realizing the health risks of antibiotic resistance to human and animal populations who are dependent on Lake Taihu for water consumption. PMID:24240317

  12. Antibiotic Resistance and Antibiotic Resistance Genes in Escherichia coli Isolates from Hospital Wastewater in Vietnam.

    Science.gov (United States)

    Lien, La Thi Quynh; Lan, Pham Thi; Chuc, Nguyen Thi Kim; Hoa, Nguyen Quynh; Nhung, Pham Hong; Thoa, Nguyen Thi Minh; Diwan, Vishal; Tamhankar, Ashok J; Stålsby Lundborg, Cecilia

    2017-06-29

    The environmental spread of antibiotic-resistant bacteria has been recognised as a growing public health threat for which hospitals play a significant role. The aims of this study were to investigate the prevalence of antibiotic resistance and antibiotic resistance genes (ARGs) in Escherichia coli isolates from hospital wastewater in Vietnam. Wastewater samples before and after treatment were collected using continuous sampling every month over a year. Standard disk diffusion and E-test were used for antibiotic susceptibility testing. Extended-spectrum beta-lactamase (ESBL) production was tested using combined disk diffusion. ARGs were detected by polymerase chain reactions. Resistance to at least one antibiotic was detected in 83% of isolates; multidrug resistance was found in 32%. The highest resistance prevalence was found for co-trimoxazole (70%) and the lowest for imipenem (1%). Forty-three percent of isolates were ESBL-producing, with the bla TEM gene being more common than bla CTX-M . Co-harbouring of the bla CTX-M , bla TEM and qepA genes was found in 46% of isolates resistant to ciprofloxacin. The large presence of antibiotic-resistant E. coli isolates combined with ARGs in hospital wastewater, even post-treatment, poses a threat to public health. It highlights the need to develop effective processes for hospital wastewater treatment plants to eliminate antibiotic resistant bacteria and ARGs.

  13. Dominance of multidrug resistant CC271 clones in macrolide-resistant streptococcus pneumoniae in Arizona

    Directory of Open Access Journals (Sweden)

    Bowers Jolene R

    2012-01-01

    Full Text Available Abstract Background Rates of resistance to macrolide antibiotics in Streptococcus pneumoniae are rising around the world due to the spread of mobile genetic elements harboring mef(E and erm(B genes and post-vaccine clonal expansion of strains that carry them. Results Characterization of 592 clinical isolates collected in Arizona over a 10 year period shows 23.6% are macrolide resistant. The largest portion of the macrolide-resistant population, 52%, is dual mef(E/erm(B-positive. All dual-positive isolates are multidrug-resistant clonal lineages of Taiwan19F-14, mostly multilocus sequence type 320, carrying the recently described transposon Tn2010. The remainder of the macrolide resistant S. pneumoniae collection includes 31% mef(E-positive, and 9% erm(B-positive strains. Conclusions The dual-positive, multidrug-resistant S. pneumoniae clones have likely expanded by switching to non-vaccine serotypes after the heptavalent pneumococcal conjugate vaccine release, and their success limits therapy options. This upsurge could have a considerable clinical impact in Arizona.

  14. Evolution of methicillin-resistant Staphylococcus aureus towards increasing resistance

    DEFF Research Database (Denmark)

    Strommenger, Birgit; Bartels, Mette Damkjær; Kurt, Kevin

    2014-01-01

    To elucidate the evolutionary history of Staphylococcus aureus clonal complex (CC) 8, which encompasses several globally distributed epidemic lineages, including hospital-associated methicillin-resistant S. aureus (MRSA) and the highly prevalent community-associated MRSA clone USA300.......To elucidate the evolutionary history of Staphylococcus aureus clonal complex (CC) 8, which encompasses several globally distributed epidemic lineages, including hospital-associated methicillin-resistant S. aureus (MRSA) and the highly prevalent community-associated MRSA clone USA300....

  15. Controlling antibiotic resistance in the ICU

    NARCIS (Netherlands)

    Derde, L.P.G.

    2013-01-01

    Patients admitted to intensive care units (ICUs) are frequently colonized with (antibiotic-resistant) bacteria, which may lead to healthcare associated infections. Antimicrobial-resistant bacteria (AMRB), such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococci

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

    Science.gov (United States)

    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.

  17. Anticoagulant Resistance

    DEFF Research Database (Denmark)

    Heiberg, Ann-Charlotte

    Although sewer rat control is carried out in more than 80 % of all Danish municipalities, with usage of large amounts of anticoagulant rodenticides, knowledge on anticoagulant resistance among rats living in the sewers is limited. As rat problems in urban areas are believed to be related to sewer...... problems (70-90 % in UK and DK) unawareness of resistance amongst these populations of Brown rats may constitute a future control problem and knowledge on this issue has become crucial. Rats were captured in sewers from seven different locations in the suburban area of Copenhagen. Locations was chosen...... to represent different sewer rat management strategies i) no anticoagulants for approx. 20 years ii) no anticoagulants for the last 5 years and iii) continuous control for many years. Animals were tested for resistance to bromadiolone by Blood-Clotting Response test, as bromadiolone is the most frequently used...

  18. Embodied Resistance to Persuasion in Advertising

    Science.gov (United States)

    Lewinski, Peter; Fransen, Marieke L.; Tan, Ed S.

    2016-01-01

    From the literature on resistance to persuasion in advertising, much is known about how people can resist advertising by adopting resistance strategies, such as avoidance, counter-arguing, and selective attention (e.g., Fransen et al., 2015b). However, the role of emotion regulation and bodily expression in resisting persuasion is so far underexplored. This is a surprising observation if one considers that at least 40% of advertisements use positive emotions (i.e., happiness) to persuade people to like the ad, brand, and product (Weinberger et al., 1995). In this article we present a framework in which we apply previous knowledge and theories on emotion regulation and embodiment to the process of resistance to persuasion. In doing so, we specifically address the role of facial expression in the course of resistance. The literature and findings from our own research lead us to propose that people can resist persuasion by controlling their facial expression of emotion when exposed to an advertisement. Controlling the expression of emotions elicited by an ad (for example refusing to smile) might be a fruitful way to resist the ad’s persuasive potential. Moreover, we argue that co-viewers can affect embodied resistance to persuasion. Showing the viability of embodied resistance to persuasion is relevant in view of the fact that ads trying to persuade us by addressing our positive emotions are ubiquitous. Embodied resistance might help people to cope with these induced positive emotions in order to resist advertisements and might therefore work as a novel and effective strategy to resist persuasion. PMID:27574512

  19. Embodied Resistance to Persuasion in Advertising

    Directory of Open Access Journals (Sweden)

    Peter Lewinski

    2016-08-01

    Full Text Available From the literature on resistance to persuasion in advertising, much is known about how people can resist advertising by adopting resistance strategies, such as avoidance, counter-arguing and selective attention (e.g., Fransen, Verlegh, Kirmani, & Smit, 2015a. However, the role of emotion regulation and bodily expression in resisting persuasion is so far underexplored. This is a surprising observation if one considers that at least 40% of advertisements use positive emotions (i.e., happiness to persuade people to like the ad, brand, and product (Weinberger et al., 1995. In this article we present a framework in which we apply previous knowledge and theories on emotion regulation and embodiment to the process of resistance to persuasion. In doing so, we specifically address the role of facial expression in the course of resistance. Based on the literature and findings largely established in our own research, we propose that people can resist persuasion by controlling their facial expression of emotion when exposed to an advertisement. Controlling the expression of emotions elicited by an ad (for example refusing to smile might be a fruitful way to resist the ad’s persuasive potential. Moreover, we argue that co-viewers can affect embodied resistance to persuasion. Showing the viability of embodied resistance to persuasion is relevant in view of the fact that ads trying to persuade us by addressing our positive emotions are ubiquitous. Embodied resistance might help people to cope with these induced positive emotions in order to resist advertisements and might therefore work as a novel and effective strategy to resist persuasion.

  20. Embodied Resistance to Persuasion in Advertising.

    Science.gov (United States)

    Lewinski, Peter; Fransen, Marieke L; Tan, Ed S

    2016-01-01

    From the literature on resistance to persuasion in advertising, much is known about how people can resist advertising by adopting resistance strategies, such as avoidance, counter-arguing, and selective attention (e.g., Fransen et al., 2015b). However, the role of emotion regulation and bodily expression in resisting persuasion is so far underexplored. This is a surprising observation if one considers that at least 40% of advertisements use positive emotions (i.e., happiness) to persuade people to like the ad, brand, and product (Weinberger et al., 1995). In this article we present a framework in which we apply previous knowledge and theories on emotion regulation and embodiment to the process of resistance to persuasion. In doing so, we specifically address the role of facial expression in the course of resistance. The literature and findings from our own research lead us to propose that people can resist persuasion by controlling their facial expression of emotion when exposed to an advertisement. Controlling the expression of emotions elicited by an ad (for example refusing to smile) might be a fruitful way to resist the ad's persuasive potential. Moreover, we argue that co-viewers can affect embodied resistance to persuasion. Showing the viability of embodied resistance to persuasion is relevant in view of the fact that ads trying to persuade us by addressing our positive emotions are ubiquitous. Embodied resistance might help people to cope with these induced positive emotions in order to resist advertisements and might therefore work as a novel and effective strategy to resist persuasion.

  1. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... Animal & Veterinary Cosmetics Tobacco Products Animal & Veterinary Home Animal & Veterinary Safety & Health Antimicrobial Resistance Animation of Antimicrobial Resistance Share Tweet Linkedin Pin ...

  2. 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.

  3. Glyphosate resistance: state of knowledge

    Science.gov (United States)

    Sammons, Robert Douglas; Gaines, Todd A

    2014-01-01

    Studies of mechanisms of resistance to glyphosate have increased current understanding of herbicide resistance mechanisms. Thus far, single-codon non-synonymous mutations of EPSPS (5-enolypyruvylshikimate-3-phosphate synthase) have been rare and, relative to other herbicide mode of action target-site mutations, unconventionally weak in magnitude for resistance to glyphosate. However, it is possible that weeds will emerge with non-synonymous mutations of two codons of EPSPS to produce an enzyme endowing greater resistance to glyphosate. Today, target-gene duplication is a common glyphosate resistance mechanism and could become a fundamental process for developing any resistance trait. Based on competition and substrate selectivity studies in several species, rapid vacuole sequestration of glyphosate occurs via a transporter mechanism. Conversely, as the chloroplast requires transporters for uptake of important metabolites, transporters associated with the two plastid membranes may separately, or together, successfully block glyphosate delivery. A model based on finite glyphosate dose and limiting time required for chloroplast loading sets the stage for understanding how uniquely different mechanisms can contribute to overall glyphosate resistance. PMID:25180399

  4. Strigolactone biosynthesis is evolutionarily conserved, regulated by phosphate starvation and contributes to resistance against phytopathogenic fungi in a moss, Physcomitrella patens

    KAUST Repository

    Decker, Eva L.

    2017-03-06

    In seed plants, strigolactones (SLs) regulate architecture and induce mycorrhizal symbiosis in response to environmental cues. SLs are formed by combined activity of the carotenoid cleavage dioxygenases (CCDs) 7 and 8 from 9-cis-β-carotene, leading to carlactone that is converted by cytochromes P450 (clade 711; MAX1 in Arabidopsis) into various SLs. As Physcomitrella patens possesses CCD7 and CCD8 homologs but lacks MAX1, we investigated if PpCCD7 together with PpCCD8 form carlactone and how deletion of these enzymes influences growth and interactions with the environment. We investigated the enzymatic activity of PpCCD7 and PpCCD8 in vitro, identified the formed products by high performance liquid chromatography (HPLC) and LC-MS, and generated and analysed ΔCCD7 and ΔCCD8 mutants. We defined enzymatic activity of PpCCD7 as a stereospecific 9-cis-CCD and PpCCD8 as a carlactone synthase. ΔCCD7 and ΔCCD8 lines showed enhanced caulonema growth, which was revertible by adding the SL analogue GR24 or carlactone. Wild-type (WT) exudates induced seed germination in Orobanche ramosa. This activity was increased upon phosphate starvation and abolished in exudates of both mutants. Furthermore, both mutants showed increased susceptibility to phytopathogenic fungi. Our study reveals the deep evolutionary conservation of SL biosynthesis, SL function, and its regulation by biotic and abiotic cues.

  5. 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.

  6. Adriamycin resistance and radiation response

    International Nuclear Information System (INIS)

    Belli, J.A.; Harris, J.R.

    1979-01-01

    Mammalian cells (V79) in culture developed resistance to Adriamycin during continuous exposure to low levels of drug. This resistance was accompanied by change in x-ray survival properties which, in turn, depended upon the isolation of subpopulations from resistant sub lines. These changes in x-ray survival properties were characterized by reduced D/sub Q/ values and a decrease in the D/sub O/. However, these changes were not observed together in the same cell sub line. Adriamycin-resistant cells did not appear to be radiation damage repair deficient. Other phenotypic changes (cell morphology, DNA content and chromosome number) suggested mutational events coincident with the development of Adriamycin resistance

  7. Measuring The Contact Resistances Of Photovoltaic Cells

    Science.gov (United States)

    Burger, D. R.

    1985-01-01

    Simple method devised to measure contact resistances of photovoltaic solar cells. Method uses readily available equipment and applicable at any time during life of cell. Enables evaluation of cell contact resistance, contact-end resistance, contact resistivity, sheet resistivity, and sheet resistivity under contact.

  8. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... More in Antimicrobial Resistance National Antimicrobial Resistance Monitoring System ... If you need help accessing information in different file formats, see Instructions for Downloading ...

  9. Staphylococcus aureus: methicillin-susceptible S. aureus to methicillin-resistant S. aureus and vancomycin-resistant S. aureus.

    Science.gov (United States)

    Rehm, Susan J; Tice, Alan

    2010-09-15

    The evolution of methicillin-resistant and vancomycin-resistant Staphylococcus aureus has demanded serious review of antimicrobial use and development of new agents and revised approaches to prevent and overcome drug resistance. Depending on local conditions and patient risk factors, empirical therapy of suspected S. aureus infection may require coverage of drug-resistant organisms with newer agents and novel antibiotic combinations. The question of treatment with inappropriate antibiotics raises grave concerns with regard to methicillin-resistant S. aureus selection, overgrowth, and increased virulence. Several strategies to reduce the nosocomial burden of resistance are suggested, including shortened hospital stays and outpatient parenteral antimicrobial therapy of the most serious infections.

  10. Risk of vancomycin-resistant enterococci bloodstream infection among patients colonized with vancomycin-resistant enterococci

    Directory of Open Access Journals (Sweden)

    Ahu Kara

    2015-01-01

    Conclusion: In conclusion, our study found that 1.55% of vancomycin-resistant enterococci-colonized children had developed vancomycin-resistant enterococci bloodstream infection among the pediatric intensive care unit and hematology/oncology patients; according to our findings, we suggest that immunosupression is the key point for developing vancomycin-resistant enterococci bloodstream infections.

  11. Relationship between Psidium species (Myrtaceae) by resistance gene analog markers: focus on nematode resistance.

    Science.gov (United States)

    Noia, L R; Tuler, A C; Ferreira, A; Ferreira, M F S

    2017-03-16

    Guava (Psidium guajava L.) crop is severely affected by the nematode Meloidogyne enterolobii. Native Psidium species have been reported as sources of resistance against this nematode. Knowledge on the molecular relationship between Psidium species based on plant resistance gene analogs (RGA) can be useful in the genetic breeding of guava for resistance to M. enterolobii. In this study, RGA markers from conserved domains, and structural features of plant R genes, were employed to characterize Psidium species and establish genetic proximity, with a focus on nematode resistance. SSR markers were also applied owing to their neutral nature, thus differing from RGA markers. For this, species reported as sources of resistance to M. enterolobii, such as P. cattleianum and P. friedrichsthalianum, as well as species occurring in the Atlantic Rainforest and susceptible genotypes, were investigated. In 10 evaluated Psidium species, high interspecific genetic variability was verified through RGA and SSR markers, with intraspecific variation in P. guajava higher with SSR, as was expected. Resistant species were clustered by RGA markers, and differential amplicons among genotypes resistant and susceptible to M. enterolobii were identified. Knowledge on the molecular relationships between Psidium species constitutes useful information for breeding of the guava tree, providing direction for hybridization and material for rootstocks. Additionally, the genetic relationship between native species, which have been little studied, and P. guajava were estimated by RGAs, which were confirmed as important markers for genetic diversity related to pathogen resistance.

  12. The tetracycline resistance determinant Tet 39 and the sulphonamide resistance gene sulII are common among resistant Acinetobacter spp. isolated from integrated fish farms in Thailand

    DEFF Research Database (Denmark)

    Agersø, Yvonne; Petersen, Andreas

    2007-01-01

    Objectives: To determine the genetic basis for tetracycline and sulphonamide resistance and the prevalence of class I and II integrons in oxytetracycline-resistant Acinetobacter spp. from integrated fish farms in Thailand. Methods: A total of 222 isolates were screened for tetracycline resistance...... and Southern blots with sulII and tet(39) probes were performed on selected isolates. Results: The recently identified tetracycline resistance gene tet(39) was demonstrated in 75% (166/222) of oxytetracycline-resistant Acinetobacter spp. from integrated fish farms in Thailand. Isolates that were also...

  13. Incidence of multidrug-resistant, extensively drug-resistant and pan-drug-resistant bacteria in children hospitalized at Dr. Hasan Sadikin general hospital Bandung Indonesia

    Science.gov (United States)

    Adrizain, R.; Suryaningrat, F.; Alam, A.; Setiabudi, D.

    2018-03-01

    Antibiotic resistance has become a global issue, with 700,000 deaths attributable to multidrug-resistance (MDR) occurring each year. Centers for Disease Control and Prevention (CDC) show rapidly increasing rates of infection due to antibiotic-resistant bacteria. The aim of the study isto describe the incidence of MDR, extensively drug-resistant (XDR) and pan drug-resistant (PDR) in Enterococcus spp., Staphylococcus aureus, K. pneumonia, Acinetobacter baumanii, P. aeruginosin, and Enterobacter spp. (ESKAPE) pathogens in children admitted to Dr. Hasan Sadikin Hospital. All pediatric patients having blood culture drawn from January 2015 to December 2016 were retrospectively studied. Data include the number of drawn blood culture, number of positive results, type of bacteria, sensitivity pattern. International standard definitions for acquired resistance by ECDC and CDC was used as definitions for MDR, XDR and PDR bacteria. From January 2015 to December 2016, 299 from 2.542 (11.7%) blood culture was positive, with Staphylococcus aureus, Enterococcus spp., Enterobacteriaceae, Pseudomonas aeruginosa, Acinetobacter spp., respectively 5, 6, 24, 5, 20 with total 60 (20%). The MDR and XDR pathogen found were 47 and 13 patients, respectively.

  14. Multidrug-Resistant Salmonella enterica Serovar Muenchen from Pigs and Humans and Potential Interserovar Transfer of Antimicrobial Resistance

    OpenAIRE

    Gebreyes, Wondwossen A.; Thakur, Siddhartha

    2005-01-01

    Salmonella serovars are important reservoirs of antimicrobial resistance. Recently, we reported on multidrug-resistant (MDR) Salmonella enterica serovar Typhimurium strains among pigs with resistance to ampicillin, kanamycin, streptomycin, sulfamethoxazole, and tetracycline (resistance [R] type AKSSuT) and resistance to amoxicillin-clavulanic acid, ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, and tetracycline (R type AxACSSuT). In the present study, 67 isolates (39 from humans...

  15. Antimicrobial resistance

    DEFF Research Database (Denmark)

    Llor, Carl; Bjerrum, Lars

    2014-01-01

    Antimicrobial resistance is a global public health challenge, which has accelerated by the overuse of antibiotics worldwide. Increased antimicrobial resistance is the cause of severe infections, complications, longer hospital stays and increased mortality. Overprescribing of antibiotics......-the-counter sale of antibiotics, the use of antimicrobial stewardship programmes, the active participation of clinicians in audits, the utilization of valid rapid point-of-care tests, the promotion of delayed antibiotic prescribing strategies, the enhancement of communication skills with patients with the aid...

  16. 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.

  17. 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.

  18. Insecticides resistance in the Culex quinquefasciatus populations from northern Thailand and possible resistance mechanisms.

    Science.gov (United States)

    Yanola, Jintana; Chamnanya, Saowanee; Lumjuan, Nongkran; Somboon, Pradya

    2015-09-01

    The mosquito vector Culex quinquefasciatus is known to be resistant to insecticides worldwide, including Thailand. This study was the first investigation of the insecticide resistance mechanisms, involving metabolic detoxification and target site insensitivity in C. quinquefasciatus from Thailand. Adult females reared from field-caught larvae from six provinces of northern Thailand were determined for resistant status by exposing to 0.05% deltamethrin, 0.75% permethrin and 5% malathion papers using the standard WHO susceptibility test. The overall mortality rates were 45.8%, 11.4% and 80.2%, respectively. A fragment of voltage-gated sodium channel gene was amplified and sequenced to identify the knock down resistance (kdr) mutation. The ace-1 gene mutation was determined by using PCR-RFLP. The L1014F kdr mutation was observed in all populations, but the homozygous mutant F/F1014 genotype was found only in two of the six provinces where the kdr mutation was significantly correlated with deltamethrin resistance. However, none of mosquitoes had the G119S mutation in the ace-1 gene. A laboratory deltamethrin resistant strain, Cq_CM_R, has been established showing a highly resistant level after selection for a few generations. The mutant F1014 allele frequency was significantly increased after one generation of selection. A synergist assay was performed to assess the metabolic detoxifying enzymes. Addition of bis(4-nitrophenyl)-phosphate (BNPP) and diethyl maleate (DEM), inhibitors of esterases and glutathione S-transferases (GST), respectively, into the larval bioassay of the Cq_CM strain with deltamethrin showed no significant reduction. By contrast, addition of piperonyl butoxide (PBO), an inhibitor of cytochrome P450 monooxygenases, showed a 9-fold reduction of resistance. Resistance to pyrethroids in C. quinquefasciatus is widely distributed in northern Thailand. This study reports for the first time for the detection of the L1014F kdr mutation in wild populations

  19. Antibiotic resistance and resistance genes in Escherichia coli from poultry farms, southwest Nigeria

    OpenAIRE

    Adelowo, Olawale O.; Fagade, Obasola E.; Agersø, Yvonne

    2014-01-01

    Introduction: This study investigated the mechanisms of resistance in 36 E. coli isolated from waste, litter, soil and water samples collected from poultry farms in Southwestern Nigeria. Methodology: Minimum inhibitory concentration (MIC) distributions of the isolates were determined using the methods of the Clinical and Laboratory Standard Institute and resistance genes detected by PCR. Results: A total of 30 isolates (94%) showed resistance to more than one antimicrobial. Percentage resista...

  20. Preventing drug resistance in severe influenza

    Science.gov (United States)

    Dobrovolny, Hana; Deecke, Lucas

    2015-03-01

    Severe, long-lasting influenza infections are often caused by new strains of influenza. The long duration of these infections leads to an increased opportunity for the emergence of drug resistant mutants. This is particularly problematic for new strains of influenza since there is often no vaccine, so drug treatment is the first line of defense. One strategy for trying to minimize drug resistance is to apply periodic treatment. During treatment the wild-type virus decreases, but resistant virus might increase; when there is no treatment, wild-type virus will hopefully out-compete the resistant virus, driving down the number of resistant virus. We combine a mathematical model of severe influenza with a model of drug resistance to study emergence of drug resistance during a long-lasting infection. We apply periodic treatment with two types of antivirals: neuraminidase inhibitors, which block release of virions; and adamantanes, which block replication of virions. We compare the efficacy of the two drugs in reducing emergence of drug resistant mutants and examine the effect of treatment frequency on the emergence of drug resistant mutants.

  1. Antibacterial resistance: an emerging 'zoonosis'?

    Science.gov (United States)

    Labro, Marie-Thérèse; Bryskier, Jean-Marie

    2014-12-01

    Antibacterial resistance is a worldwide threat, and concerns have arisen about the involvement of animal commensal and pathogenic bacteria in the maintenance and spread of resistance genes. However, beyond the facts related to the occurrence of resistant microorganisms in food, food-producing animals and companion animals and their transmission to humans, it is important to consider the vast environmental 'resistome', the selective pathways underlying the emergence of antibacterial resistance and how we can prepare answers for tomorrow.

  2. Study on drug resistance of mycobacterium tuberculosis in patients with pulmonary tuberculosis by drug resistance gene detecting

    International Nuclear Information System (INIS)

    Wang Wei; Li Hongmin; Wu Xueqiong; Wang Ansheng; Ye Yixiu; Wang Zhongyuan; Liu Jinwei; Chen Hongbing; Lin Minggui; Wang Jinhe; Li Sumei; Jiang Ping; Feng Bai; Chen Dongjing

    2004-01-01

    To investigate drug resistance of mycobacterium tuberculosis in different age group, compare detecting effect of two methods and evaluate their the clinical application value, all of the strains of mycobacterium tuberculosis were tested for resistance to RFP, INH SM PZA and EMB by the absolute concentration method on Lowenstein-Jensen medium and the mutation of the rpoB, katG, rpsL, pncA and embB resistance genes in M. tuberculosis was tested by PCR-SSCP. In youth, middle and old age group, the rate of acquired drug resistance was 89.2%, 85.3% and 67.6% respectively, the gene mutation rate was 76.2%, 81.3% and 63.2% respectively. The rate of acquired drug resistance and multiple drug resistance in youth group was much higher than those in other groups. The gene mutation was correlated with drug resistance level of mycobacterium tuberculosis. The gene mutation rate was higher in strains isolated from high concentration resistance than those in strains isolated from low concentration resistance. The more irregular treatment was longer, the rate of drug resistance was higher. Acquired drug resistance varies in different age group. It suggested that surveillance of drug resistence in different age group should be taken seriously, especially in youth group. PCR - SSCP is a sensitive and specific method for rapid detecting rpoB, katG, rpsL, pncA and embB genes mutations of MTB. (authors)

  3. Buprofezin susceptibility survey, resistance selection and preliminary determination of the resistance mechanism in Nilaparvata lugens (Homoptera: Delphacidae).

    Science.gov (United States)

    Wang, Yanhua; Gao, Congfen; Xu, Zhiping; Zhu, Yu Cheng; Zhang, Jiushuang; Li, Wenhong; Dai, Dejiang; Lin, Youwei; Zhou, Weijun; Shen, Jinliang

    2008-10-01

    Buprofezin has been used for many years to control Nilaparvata lugens (Stål). Assessment of susceptibility change in the insect is essential for maintaining control efficiency and resistance management. Eleven-year surveys showed that most field populations were susceptible before 2004. However, substantially higher levels of resistance (up to 28-fold) were found in most of the rice fields in China after 2004. A field population was collected and periodically selected for buprofezin resistance in the laboratory. After 65 generations (56 were selected), the colony successfully obtained 3599-fold resistance to buprofezin. Synergism tests showed that O,O-diethyl-O-phenyl phosphorothioate (SV1), piperonyl butoxide (PBO) and diethyl maleate (DEM) increased buprofezin toxicity in the resistant strain by only 1.5-1.6 fold, suggesting that esterases, P450-monooxygenases and glutathione S-transferases had no substantial effect on buprofezin resistance development. The results from this study indicate that N. lugens has the potential to develop high resistance to buprofezin. A resistance management program with rotation of buprofezin and other pesticides may efficiently delay or slow down resistance development in the insect. Further investigation is also necessary to understand the resistance mechanisms in N. lugens.

  4. Collateral Resistance and Sensitivity Modulate Evolution of High-Level Resistance to Drug Combination Treatment in Staphylococcus aureus

    DEFF Research Database (Denmark)

    de Evgrafov, Mari Cristina Rodriguez; Gumpert, Heidi; Munck, Christian

    2015-01-01

    As drug-resistant pathogens continue to emerge, combination therapy will increasingly be relied upon to treat infections and to help combat further development of multidrug resistance. At present a dichotomy exists between clinical practice, which favors therapeutically synergistic combinations......, to reflect drug concentrations more likely to be encountered during treatment. We performed a series of adaptive evolution experiments using Staphylococcus aureus. Interestingly, no relationship between drug interaction type and resistance evolution was found as resistance increased significantly beyond wild......-type levels. All drug combinations, irrespective of interaction types, effectively limited resistance evolution compared with monotreatment. Cross-resistance and collateral sensitivity were found to be important factors in the extent of resistance evolution toward a combination. Comparative genomic analyses...

  5. 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.

    Science.gov (United States)

    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.

  6. Increasing Incidence of Linezolid-Intermediate or -Resistant, Vancomycin-Resistant Enterococcus faecium Strains Parallels Increasing Linezolid Consumption▿

    OpenAIRE

    Scheetz, Marc H.; Knechtel, Stephanie A.; Malczynski, Michael; Postelnick, Michael J.; Qi, Chao

    2008-01-01

    Clinical enterococcal resistance to linezolid is defined by the presence of the G2576T mutation. We evaluated the incidence of genetically proven linezolid resistance among vancomycin-resistant Enterococcus faecium strains and linezolid consumption for a possible association. A relationship was found (r2 = 0.73, P = 0.03) and predicts increasing resistance with current trends of linezolid use.

  7. Electromigration early resistance increase measurements

    NARCIS (Netherlands)

    Niehof, J.; Flinn, P.A.; Maloney, T.J.

    1993-01-01

    An early resistance change measurement set-up, using an AC bridge technique, has been developed, and measurements have been performed. Large sample-to-sample variations occur. The characteristic time for the resistance change curve is shorter for resistance increase (under current stress) than for

  8. Analysis of metal and biocides resistance genes in drug resistance and susceptible Salmonella enterica from food animals

    Science.gov (United States)

    Background Generally drug resistant bacteria carry antibiotic resistance genes and heavy metal and biocide resistance genes on large conjugative plasmids. The presence of these metal and biocide resistance genes in susceptible bacteria are not assessed comprehensively. Hence, WGS data of susceptib...

  9. Resistance of green lacewing, Chrysoperla carnea Stephens to nitenpyram: Cross-resistance patterns, mechanism, stability, and realized heritability.

    Science.gov (United States)

    Mansoor, Muhammad Mudassir; Raza, Abu Bakar Muhammad; Abbas, Naeem; Aqueel, Muhammad Anjum; Afzal, Muhammad

    2017-01-01

    The green lacewing, Chrysoperla carnea Stephens (Neuroptera: Chrysopidae) is a major generalist predator employed in integrated pest management (IPM) plans for pest control on many crops. Nitenpyram, a neonicotinoid insecticide has widely been used against the sucking pests of cotton in Pakistan. Therefore, a field green lacewing strain was exposed to nitenpyram for five generations to investigate resistance evolution, cross-resistance pattern, stability, realized heritability, and mechanisms of resistance. Before starting the selection with nitenpyram, a field collected strain showed 22.08-, 23.09-, 484.69- and 602.90-fold resistance to nitenpyram, buprofezin, spinosad and acetamiprid, respectively compared with the Susceptible strain. After continuous selection for five generations (G1-G5) with nitenpyram in the laboratory, the Field strain (Niten-SEL) developed a resistance ratio of 423.95 at G6. The Niten-SEL strain at G6 showed no cross-resistance to buprofezin and acetamiprid and negative cross-resistance to spinosad compared with the Field strain (G1). For resistance stability, the Niten-SEL strain was left unexposed to any insecticide for four generations (G6-G9) and bioassay results at G10 showed that resistance to nitenpyram, buprofezin and spinosad was stable, while resistance to acetamiprid was unstable. The realized heritability values were 0.97, 0.16, 0.03, and -0.16 to nitenpyram, buprofezin, acetamiprid and spinosad, respectively, after five generations of selection. Moreover, the enzyme inhibitors (PBO or DEF) significantly decreased the nitenpyram resistance in the resistant strain, suggesting that resistance was due to microsomal oxidases and esterases. These results are very helpful for integration of green lacewings in IPM programs. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Antimicrobial Resistance of Hypervirulent Klebsiella pneumoniae: Epidemiology, Hypervirulence-Associated Determinants, and Resistance Mechanisms

    Directory of Open Access Journals (Sweden)

    Chang-Ro Lee

    2017-11-01

    Full Text Available Klebsiella pneumoniae is one of the most clinically relevant species in immunocompromised individuals responsible for community-acquired and nosocomial infections, including pneumonias, urinary tract infections, bacteremias, and liver abscesses. Since the mid-1980s, hypervirulent K. pneumoniae, generally associated with the hypermucoviscosity phenotype, has emerged as a clinically significant pathogen responsible for serious disseminated infections, such as pyogenic liver abscesses, osteomyelitis, and endophthalmitis, in a generally younger and healthier population. Hypervirulent K. pneumoniae infections were primarily found in East Asia and now are increasingly being reported worldwide. Although most hypervirulent K. pneumoniae isolates are antibiotic-susceptible, some isolates with combined virulence and resistance, such as the carbapenem-resistant hypervirulent K. pneumoniae isolates, are increasingly being detected. The combination of multidrug resistance and enhanced virulence has the potential to cause the next clinical crisis. To better understand the basic biology of hypervirulent K. pneumoniae, this review will provide a summarization and discussion focused on epidemiology, hypervirulence-associated factors, and antibiotic resistance mechanisms of such hypervirulent strains. Epidemiological analysis of recent clinical isolates in China warns the global dissemination of hypervirulent K. pneumoniae strains with extensive antibiotic resistance in the near future. Therefore, an immediate response to recognize the global dissemination of this hypervirulent strain with resistance determinants is an urgent priority.

  11. Antibiotic resistance increases with local temperature

    Science.gov (United States)

    MacFadden, Derek R.; McGough, Sarah F.; Fisman, David; Santillana, Mauricio; Brownstein, John S.

    2018-06-01

    Bacteria that cause infections in humans can develop or acquire resistance to antibiotics commonly used against them1,2. Antimicrobial resistance (in bacteria and other microbes) causes significant morbidity worldwide, and some estimates indicate the attributable mortality could reach up to 10 million by 20502-4. Antibiotic resistance in bacteria is believed to develop largely under the selective pressure of antibiotic use; however, other factors may contribute to population level increases in antibiotic resistance1,2. We explored the role of climate (temperature) and additional factors on the distribution of antibiotic resistance across the United States, and here we show that increasing local temperature as well as population density are associated with increasing antibiotic resistance (percent resistant) in common pathogens. We found that an increase in temperature of 10 °C across regions was associated with an increases in antibiotic resistance of 4.2%, 2.2%, and 2.7% for the common pathogens Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus. The associations between temperature and antibiotic resistance in this ecological study are consistent across most classes of antibiotics and pathogens and may be strengthening over time. These findings suggest that current forecasts of the burden of antibiotic resistance could be significant underestimates in the face of a growing population and climate change4.

  12. Resistance to dual-gene Bt maize in Spodoptera frugiperda: selection, inheritance, and cross-resistance to other transgenic events.

    Science.gov (United States)

    Santos-Amaya, Oscar F; Rodrigues, João V C; Souza, Thadeu C; Tavares, Clébson S; Campos, Silverio O; Guedes, Raul N C; Pereira, Eliseu J G

    2015-12-17

    Transgenic crop "pyramids" producing two or more Bacillus thuringiensis (Bt) toxins active against the same pest are used to delay evolution of resistance in insect pest populations. Laboratory and greenhouse experiments were performed with fall armyworm, Spodoptera frugiperda, to characterize resistance to Bt maize producing Cry1A.105 and Cry2Ab and test some assumptions of the "pyramid" resistance management strategy. Selection of a field-derived strain of S. frugiperda already resistant to Cry1F maize with Cry1A.105 + Cry2Ab maize for ten generations produced resistance that allowed the larvae to colonize and complete the life cycle on these Bt maize plants. Greenhouse experiments revealed that the resistance was completely recessive (Dx = 0), incomplete, autosomal, and without maternal effects or cross-resistance to the Vip3Aa20 toxin produced in other Bt maize events. This profile of resistance supports some of the assumptions of the pyramid strategy for resistance management. However, laboratory experiments with purified Bt toxin and plant leaf tissue showed that resistance to Cry1A.105 + Cry2Ab2 maize further increased resistance to Cry1Fa, which indicates that populations of fall armyworm have high potential for developing resistance to some currently available pyramided maize used against this pest, especially where resistance to Cry1Fa was reported in the field.

  13. Transposon characterization of vancomycin-resistant Enterococcus faecium (VREF) and dissemination of resistance associated with transferable plasmids

    DEFF Research Database (Denmark)

    Migura, Lourdes Garcia; Liebana, Ernesto; Jensen, Lars Bogø

    2007-01-01

    Objectives: VanA glycopeptide resistance has persisted on broiler farms in the UK despite the absence of the antimicrobial selective pressure, avoparcin. This study aimed to investigate the contribution of horizontal gene transfer of Tn 1546 versus clonal spread in the dissemination of the resist......Objectives: VanA glycopeptide resistance has persisted on broiler farms in the UK despite the absence of the antimicrobial selective pressure, avoparcin. This study aimed to investigate the contribution of horizontal gene transfer of Tn 1546 versus clonal spread in the dissemination...... plasmid replicons, associated with antimicrobial resistance on several unrelated farms. Conclusions: Horizontal transfer of vancomycin resistance may play a more important role in the persistence of antimicrobial resistance than clonal spread. The presence of different plasmid replicons, associated...... with antimicrobial resistance on several unrelated farms, illustrates the ability of these enterococci to acquire and disseminate mobile genetic elements within integrated livestock systems....

  14. Production of low-affinity penicillin-binding protein by low- and high-resistance groups of methicillin-resistant Staphylococcus aureus.

    Science.gov (United States)

    Murakami, K; Nomura, K; Doi, M; Yoshida, T

    1987-01-01

    Methicillin- and cephem-resistant Staphylococcus aureus (137 strains) for which the cefazolin MICs are at least 25 micrograms/ml could be classified into low-resistance (83% of strains) and high-resistance (the remaining 17%) groups by the MIC of flomoxef (6315-S), a 1-oxacephalosporin. The MICs were less than 6.3 micrograms/ml and more than 12.5 micrograms/ml in the low- and high-resistance groups, respectively. All strains produced penicillin-binding protein 2' (PBP 2'), which has been associated with methicillin resistance and which has very low affinity for beta-lactam antibiotics. Production of PBP 2' was regulated differently in low- and high-resistance strains. With penicillinase-producing strains of the low-resistance group, cefazolin, cefamandole, and cefmetazole induced PBP 2' production about 5-fold, while flomoxef induced production 2.4-fold or less. In contrast, penicillinase-negative variants of low-resistance strains produced PBP 2' constitutively in large amounts and induction did not occur. With high-resistance strains, flomoxef induced PBP 2' to an extent similar to that of cefazolin in both penicillinase-producing and -negative strains, except for one strain in which the induction did not occur. The amount of PBP 2' induced by beta-lactam antibiotics in penicillinase-producing strains of the low-resistance group correlated well with resistance to each antibiotic. Large amounts of PBP 2' in penicillinase-negative variants of the low-resistance group did not raise the MICs of beta-lactam compounds, although these strains were more resistant when challenged with flomoxef for 2 h. Different regulation of PBP 2' production was demonstrated in the high- and low-resistance groups, and factor(s) other than PBP 2' were suggested to be involved in the methicillin resistance of high-resistance strains. Images PMID:3499861

  15. Levantamento etnobotânico de plantas popularmente utilizadas como antiúlceras e antiinflamatórias pela comunidade de Pirizal, Nossa Senhora do Livramento-MT, Brasil

    Directory of Open Access Journals (Sweden)

    Neyres Zínia Taveira de Jesus

    Full Text Available O trabalho teve por objetivo proceder o levantamento etnobotânico das espécies vegetais utilizadas popularmente no Distrito de Pirizal - MT, no pantanal mato-grossense, como antiúlceras e antiinflamatórias. A entrevista aberta foi realizada através da aplicação de um roteiro base a 38 informantes adultos, na faixa etária de 25 a 75 anos. Indagou-se o nome popular das plantas, partes utilizadas, preparados e vias de administração, e realizou-se a revisão bibliográfica das plantas mais citadas no estudo, utilizando-se as bases de dados convencionais. Foram citadas 49 espécies pertencentes a 47 gêneros e 32 famílias, destacando-se a família Fabaceae. As plantas mais citadas simultaneamente como antiúlceras e antiinflamatórias foram Lafoensia pacari St. Hil. (9,2%, Hyptis crenata Pohl (8,8%, Hyptis suaveolens (L. Poit (6,7%, Stachytarpheta cayenensis (L.C.Rich Vahl (5,8%, Waltheria indica L. (5%, Strychnos pseudoquina St. Hil. (4,2% e Vatairea macrocarpa (Benth. Ducke (3,3%. A parte da planta mais citada foi a folha (57,1%, a via de administração mais utilizada no tratamento das úlceras gástricas foi a oral (100%, com preferência para os chás (75%, enquanto nas inflamações foram os banhos tópicos (60%.. A revisão bibliográfica apontou a necessidade de aprofundar os estudos químico-farmacológicos para Vatairea macrocarpa (Benth. Ducke e Hyptis crenata Pohl.

  16. Resistance to Barley Leaf Stripe

    DEFF Research Database (Denmark)

    Nørgaard Knudsen, J. C.

    1986-01-01

    in well adapted Northwest European spring cultivars. Virulence matching two hitherto not overcome resistances was demonstrated. Differences in apparent race nonspecific or partial resistance were also present, changing the percentage of infected plants of susceptible genotypes from about 20 to 44 per cent.......Ten barley [Hordeum vulgare] genotypes were inoculated with twelve isolates of Pyrenophora graminea of diverse European and North African origin. Race specific resistance occurred. Four, possibly five, genetically different sources of race-specific resistance were found, three of them occurring...

  17. Cross-resistance to radiation in human squamous cell carcinoma cells with induced cisplatin resistance

    International Nuclear Information System (INIS)

    Komori, Keiichi

    1998-01-01

    Accumulated evidence indicates that drug resistance is induced in tumor cells treated with a variety of anti-cancer drugs and that there is a possibility of cross-resistance to ionizing radiation associated with induced drug resistance. Most in vitro studies have shown inconsistent results on cross-resistance probably because of different cell lines used and protocols for drug induction. In this study, TE3 human squamous cell carcinoma cell line was treated with a 4-day cycle of cisplatin (cis-diamminedichloroplatinum (II); CDDP) at a concentration yielding 10% cell survival. The treatment was repeated up to 3 cycles. After treatment, cells were tested for CDDP and X-ray sensitivity. One cycle of CDDP treatment induced CDDP resistance with a factor of 1.41 and 2 cycles of the treatment with a factor of 1.86. The resistance factor reached a plateau at 3 cycles of treatment. For analyzing the correlation of CDDP and X-ray resistance, 30 clones from both untreated and 3-cycle treated cells were isolated and analyzed for CDDP and X-ray sensitivity. The sensitivity was expressed as the concentration of drug or dose of X-ray required to reduce the cell survival to x% (Dx). The correlation coefficient of clones with 3-cycle treatment between CDDP and X-ray sensitivity increased gradually by increasing the end point of Dx from D 10 to D 90 , resulting in significant correlation at D 90 . The result suggested that there is a certain common repair-related mechanism affecting both CDDP and X-ray resistance in CDDP-treated cells. (author)

  18. 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

  19. Overview of glyphosate-resistant weeds worldwide.

    Science.gov (United States)

    Heap, Ian; Duke, Stephen O

    2018-05-01

    Glyphosate is the most widely used and successful herbicide discovered to date, but its utility is now threatened by the occurrence of several glyphosate-resistant weed species. Glyphosate resistance first appeared in Lolium rigidum in an apple orchard in Australia in 1996, ironically the year that the first glyphosate-resistant crop (soybean) was introduced in the USA. Thirty-eight weed species have now evolved resistance to glyphosate, distributed across 37 countries and in 34 different crops and six non-crop situations. Although glyphosate-resistant weeds have been identified in orchards, vineyards, plantations, cereals, fallow and non-crop situations, it is the glyphosate-resistant weeds in glyphosate-resistant crop systems that dominate the area infested and growing economic impact. Glyphosate-resistant weeds present the greatest threat to sustained weed control in major agronomic crops because this herbicide is used to control weeds with resistance to herbicides with other sites of action, and no new herbicide sites of action have been introduced for over 30 years. Industry has responded by developing herbicide resistance traits in major crops that allow existing herbicides to be used in a new way. However, over reliance on these traits will result in multiple-resistance in weeds. Weed control in major crops is at a precarious point, where we must maintain the utility of the herbicides we have until we can transition to new weed management technologies. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  20. Antibiotic resistance of lactic acid bacteria

    Directory of Open Access Journals (Sweden)

    Bulajić Snežana

    2008-01-01

    Full Text Available Knowledge on the antibiotic resistance of lactic acid bacteria is still limited, possibly because of the large numbers of genera and species encountered in this group, as well as variances in their resistance spectra. The EFSA considers antibiotic resistances, especially transferable resistances, an important decision criterion for determining a strain's QPS status. There are no approved standards for the phenotypic or genotypic evaluation of antibiotic resistances in food isolates. Also, the choice of media is problematic, as well as the specification of MIC breakpoint values as a result of the large species variation and the possible resulting variation in MIC values between species and genera. The current investigations in this field showed that we might end up with a range of different species- or genus-specific breakpoint values that may further increase the current complexity. Another problem associated with safety determinations of starter strains is that once a resistance phenotype and an associated resistance determinant have been identified, it becomes difficult to show that this determinant is not transferable, especially if the resistance gene is not located on a plasmid and no standard protocols for showing genetic transfer are available. Encountering those problems, the QPS system should allow leeway for the interpretations of results, especially when these relate to the methodology for resistance phenotype determinations, determinations of MIC breakpoints for certain genera, species, or strains, the nondeterminability of a genetic basis of a resistance phenotype and the transferability of resistance genes.

  1. Antiretroviral Resistance in HIV/AIDS Patients

    Science.gov (United States)

    Manosuthi, W.; MD

    2018-03-01

    The higher prevalence of HIV drug resistance was observed in areas with greater ART coverage. The HIV resistance-associated mutations occur when people have inadequate levels of antiretroviral drugs as well as inadequate potency, inadequate adherence, and preexisting resistance. The degree to drug cross-resistance is observed depends on the specific mutations and number of mutation accumulation. In the Southeast Asia region, the challenging of people with treatment failure is the availability and accessibility to subsequent new antiretroviral drugs to construct he second and salvage regimen. Genotypic resistance testing is a useful tool because it can identify the existing drug resistance-associated mutations under the selective drug pressure. Thus, understanding the basic interpretation of HIV drug resistance- associated mutation is useful in guiding clinical decisions for treatment-experienced people living with HIV.

  2. Breast cancer resistance protein is localized at the plasma membrane in mitoxantrone- and topotecan-resistant cell lines

    NARCIS (Netherlands)

    Scheffer, GL; Maliepaard, M; Pijnenborg, ACLM; van Gastelen, MA; Schroeijers, AB; Allen, JD; Ross, DD; van der Valk, P; Dalton, WS; Schellens, JHM; Scheper, RJ; de Jong, MC

    2000-01-01

    Tumor cells may display a multidrug resistant phenotype by overexpression of ATP-binding cassette transporters such as multidrug resistance (,MDR1) P-glycoprotein, multidrug resistance protein 1 (MRP1), and breast cancer resistance protein (BCRP). The presence of BCRP has thus far been reported

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

    Science.gov (United States)

    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.

  4. Molecular Scree ning of Blast Resistance Genes in Rice Germplasms Resistant to Magnaporthe oryzae

    Directory of Open Access Journals (Sweden)

    Liang Yan

    2017-01-01

    Full Text Available Molecular screening of major rice blast resistance genes was determined with molecular markers, which showed close-set linkage to 11 major rice blast resistance genes (Pi-d2, Pi-z, Piz-t, Pi-9, Pi-36, Pi-37, Pi5, Pi-b, Pik-p, Pik-h and Pi-ta2, in a collection of 32 accessions resistant to Magnaporthe oryzae. Out of the 32 accessions, the Pi-d2 and Pi-z appeared to be omnipresent and gave positive express. As the second dominant, Pi-b and Piz-t gene frequencies were 96.9% and 87.5%. And Pik-h and Pik-p gene frequencies were 43.8% and 28.1%, respectively. The molecular marker linkage to Pi-ta2 produced positive bands in eleven accessions, while the molecular marker linkage to Pi-36 and Pi-37 in only three and four accessions, respectively. The natural field evaluation analysis showed that 30 of the 32 accessions were resistant, one was moderately resistant and one was susceptible. Infection types were negatively correlated with the genotype scores of Pi-9, Pi5, Pi-b, Pi-ta2 and Pik-p, although the correlation coefficients were very little. These results are useful in identification and incorporation of functional resistance genes from these germplasms into elite cultivars through marker-assisted selection for improved blast resistance in China and worldwide.

  5. Paediatrics, insulin resistance and the kidney.

    Science.gov (United States)

    Marlais, Matko; Coward, Richard J

    2015-08-01

    Systemic insulin resistance is becoming more prevalent in the young due to modern lifestyles predisposing to the metabolic syndrome and obesity. There is also evidence that there are critical insulin-resistant phases for the developing child, including puberty, and that renal disease per se causes systemic insulin resistance. This review considers the factors that render children insulin resistant, as well as the accumulating evidence that the kidney is an insulin-responsive organ and could be affected by insulin resistance.

  6. Study of multidrug resistance and radioresistance

    International Nuclear Information System (INIS)

    Kang, Yoon Koo; Yoo, Young Do

    1999-04-01

    We investigated the mechanism of 5-FU, adriamycin, radiation resistance in Korean gastric cancer cells. First we investigated the relation between Rb and multidrug resistance. Rb stable transfectants exhibited 5- to 10- fold more resistance to adriamycin than the control cells. These Rb transfectants showed increased MDR1 expression. We also investigated up-regulation in radiation-resistant tumor tissues. HSP27, MRP-8, GST, and NKEF-B were up-regulated in radiation resistant tumor. Expression of NKEF-B was also increased by radiation exposure in Head and Neck cells. These results demonstrated that NKEF-B is a stress response protein and it may have an important role in radiation resistance

  7. Analysis and modeling of resistive switching mechanism oriented to fault tolerance of resistive memory based on memristor

    International Nuclear Information System (INIS)

    Huang Da; Wu Jun-Jie; Tang Yu-Hua

    2014-01-01

    With the progress of the semiconductor industry, resistive memories, especially the memristor, have drawn increasing attention. The resistive memory based on memrsitor has not been commercialized mainly because of data error. Currently, there are more studies focused on fault tolerance of resistive memory. This paper studies the resistive switching mechanism which may have time-varying characteristics. Resistive switching mechanism is analyzed and its respective circuit model is established based on the memristor Spice model

  8. SCC mec typing and antimicrobial resistance of methicillin-resistant Staphylococcus aureus (MRSA) from pigs of Northeast India.

    Science.gov (United States)

    Rajkhowa, S; Sarma, D K; Pegu, S R

    2016-12-01

    Staphylococcus aureus is one of the most important pathogens of both humans and animal. Methicillin-resistant Staphylococcus aureus (MRSA) is an important human pathogen that causes serious infections both in hospitals and communities due to its multidrug resistance tendency. This study was undertaken to characterize the MRSA isolates from pigs and to determine the antimicrobial resistance of these isolates. Forty nine MRSA strains (one strain per positive pig) isolated from pigs of Northeast India were characterized by SCCmec typing and antimicrobial resistance. The overall prevalence of MRSA was 7.02 % with the highest prevalence recorded in pigs aged 1-3 months (P = 0.001) and in nasal samples (P = 0.005). Two SCC mec types (type III and V) were found in Indian pigs with predominance of type V. All isolates were resistant to penicillin. Seventeen resistance groups were observed where 87.75 % isolates showed multidrug resistance (showed resistance to three or more classes of antimicrobials). The most predominant resistance pattern observed was Oxytetracycline + Penicillin + Sulfadiazine + Tetracycline accounting 12.24 % of the isolates. The present study contributes to the understanding of characteristics and antimicrobial resistance of porcine MRSA isolates which in turn will help in devising strategy for the control of this pathogen. Findings of the study also throw light on multidrug resistance MRSA and emphasize the need for judicious use of antimicrobials in animal practice.

  9. Characterization of Phenacoccus solenopsis (Tinsley) (Homoptera: Pseudococcidae) Resistance to Emamectin Benzoate: Cross-Resistance Patterns and Fitness Cost Analysis.

    Science.gov (United States)

    Afzal, M B S; Shad, S A

    2016-06-01

    Cotton mealybug Phenacoccus solenopsis (Tinsley) (Homoptera: Pseudococcidae) is a sucking pest of worldwide importance causing huge losses by feeding upon cotton in various parts of the world. Because of the importance of this pest, this research was carried out to select emamectin resistance in P. solenopsis in the laboratory to study cross-resistance, stability, realized heritability, and fitness cost of emamectin resistance. After selection from third generation (G3) to G6, P. solenopsis developed very high emamectin resistance (159.24-fold) when compared to a susceptible unselected population (Unsel pop). Population selected to emamectin benzoate conferred moderate (45.81-fold), low (14.06-fold), and no cross-resistance with abamectin, cypermethrin, and profenofos, respectively compared to the Unsel pop. A significant decline in emamectin resistance was observed in the resistant population when not exposed to emamectin from G7 to G13. The estimated realized heritability (h (2)) for emamectin resistance was 0.84. A high fitness cost was associated with emamectin resistance in P. solenopsis. Results of this study may be helpful in devising insecticide resistance management strategies for P. solenopsis.

  10. Insulin Resistance and Prediabetes

    Science.gov (United States)

    ... Your Baby is Born Monogenic Diabetes Insulin Resistance & Prediabetes Insulin resistance and prediabetes occur when your body ... will stay in the healthy range. What is prediabetes? Prediabetes means your blood glucose levels are higher ...

  11. Flow resistance in rod assemblies

    International Nuclear Information System (INIS)

    Korsun, A.S.; Sokolova, M.S.

    2000-01-01

    The general form of relation between the resistance force and the velocity vector, resistance tensor structure and possible types of anisotropy in the flow thorough such structures as rod or tube assemblies are under discussion. Some questions of experimental determination of volumetric resistance force tensor are also under consideration. (author)

  12. Studying Resistance: Some Cautionary Notes

    Science.gov (United States)

    Dimitriadis, Greg

    2011-01-01

    The question of "resistance" has oriented the field of critical ethnography for several generations now. Indeed, the reproduction-resistance binary has animated much of the most important, critical work in educational studies over the last 30 years. Yet, this reproduction-resistance binary has perhaps calcified in recent years. Such work…

  13. Heat resistant protective hand covering

    Science.gov (United States)

    Tschirch, R. P.; Sidman, K. R.; Arons, I. J. (Inventor)

    1984-01-01

    A heat-resistant aromatic polyamide fiber is described. The outer surface of the shell is coated with a fire-resistant elastomer and liner. Generally conforming and secured to the shell and disposed inwardly of the shell, the liner is made of a felt fabric of temperature-resistant aromatic polymide fiber.

  14. Voltage-gated sodium channel polymorphism and metabolic resistance in pyrethroid-resistant Aedes aegypti from Brazil.

    Science.gov (United States)

    Martins, Ademir Jesus; Lins, Rachel Mazzei Moura de Andrade; Linss, Jutta Gerlinde Birgitt; Peixoto, Alexandre Afranio; Valle, Denise

    2009-07-01

    The nature of pyrethroid resistance in Aedes aegypti Brazilian populations was investigated. Quantification of enzymes related to metabolic resistance in two distinct populations, located in the Northeast and Southeast regions, revealed increases in Glutathione-S-transferase (GST) and Esterase levels. Additionally, polymorphism was found in the IIS6 region of Ae. aegypti voltage-gated sodium channel (AaNa(V)), the pyrethroid target site. Sequences were classified in two haplotype groups, A and B, according to the size of the intron in that region. Rockefeller, a susceptible control lineage, contains only B sequences. In field populations, some A sequences present a substitution in the 1011 site (Ile/Met). When resistant and susceptible individuals were compared, the frequency of both A (with the Met mutation) and B sequences were slightly increased in resistant specimens. The involvement of the AaNa(V) polymorphism in pyrethroid resistance and the metabolic mechanisms that lead to potential cross-resistance between organophosphate and pyrethroids are discussed.

  15. 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

  16. Adaptive and Mutational Resistance: Role of Porins and Efflux Pumps in Drug Resistance

    Science.gov (United States)

    Fernández, Lucía

    2012-01-01

    Summary: The substantial use of antibiotics in the clinic, combined with a dearth of new antibiotic classes, has led to a gradual increase in the resistance of bacterial pathogens to these compounds. Among the various mechanisms by which bacteria endure the action of antibiotics, those affecting influx and efflux are of particular importance, as they limit the interaction of the drug with its intracellular targets and, consequently, its deleterious effects on the cell. This review evaluates the impact of porins and efflux pumps on two major types of resistance, namely, mutational and adaptive types of resistance, both of which are regarded as key phenomena in the global rise of antibiotic resistance among pathogenic microorganisms. In particular, we explain how adaptive and mutational events can dramatically influence the outcome of antibiotic therapy by altering the mechanisms of influx and efflux of antibiotics. The identification of porins and pumps as major resistance markers has opened new possibilities for the development of novel therapeutic strategies directed specifically against these mechanisms. PMID:23034325

  17. 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

  18. In Silico Assigned Resistance Genes Confer Bifidobacterium with Partial Resistance to Aminoglycosides but Not to Β-Lactams

    Science.gov (United States)

    Fouhy, Fiona; O’Connell Motherway, Mary; Fitzgerald, Gerald F.; Ross, R. Paul; Stanton, Catherine; van Sinderen, Douwe; Cotter, Paul D.

    2013-01-01

    Bifidobacteria have received significant attention due to their contribution to human gut health and the use of specific strains as probiotics. It is thus not surprising that there has also been significant interest with respect to their antibiotic resistance profile. Numerous culture-based studies have demonstrated that bifidobacteria are resistant to the majority of aminoglycosides, but are sensitive to β-lactams. However, limited research exists with respect to the genetic basis for the resistance of bifidobacteria to aminoglycosides. Here we performed an in-depth in silico analysis of putative Bifidobacterium-encoded aminoglycoside resistance proteins and β-lactamases and assess the contribution of these proteins to antibiotic resistance. The in silico-based screen detected putative aminoglycoside and β-lactam resistance proteins across the Bifidobacterium genus. Laboratory-based investigations of a number of representative bifidobacteria strains confirmed that despite containing putative β-lactamases, these strains were sensitive to β-lactams. In contrast, all strains were resistant to the aminoglycosides tested. To assess the contribution of genes encoding putative aminoglycoside resistance proteins in Bifidobacterium sp. two genes, namely Bbr_0651 and Bbr_1586, were targeted for insertional inactivation in B. breve UCC2003. As compared to the wild-type, the UCC2003 insertion mutant strains exhibited decreased resistance to gentamycin, kanamycin and streptomycin. This study highlights the associated risks of relying on the in silico assignment of gene function. Although several putative β-lactam resistance proteins are located in bifidobacteria, their presence does not coincide with resistance to these antibiotics. In contrast however, this approach has resulted in the identification of two loci that contribute to the aminoglycoside resistance of B. breve UCC2003 and, potentially, many other bifidobacteria. PMID:24324818

  19. In silico assigned resistance genes confer Bifidobacterium with partial resistance to aminoglycosides but not to β-lactams.

    Directory of Open Access Journals (Sweden)

    Fiona Fouhy

    Full Text Available Bifidobacteria have received significant attention due to their contribution to human gut health and the use of specific strains as probiotics. It is thus not surprising that there has also been significant interest with respect to their antibiotic resistance profile. Numerous culture-based studies have demonstrated that bifidobacteria are resistant to the majority of aminoglycosides, but are sensitive to β-lactams. However, limited research exists with respect to the genetic basis for the resistance of bifidobacteria to aminoglycosides. Here we performed an in-depth in silico analysis of putative Bifidobacterium-encoded aminoglycoside resistance proteins and β-lactamases and assess the contribution of these proteins to antibiotic resistance. The in silico-based screen detected putative aminoglycoside and β-lactam resistance proteins across the Bifidobacterium genus. Laboratory-based investigations of a number of representative bifidobacteria strains confirmed that despite containing putative β-lactamases, these strains were sensitive to β-lactams. In contrast, all strains were resistant to the aminoglycosides tested. To assess the contribution of genes encoding putative aminoglycoside resistance proteins in Bifidobacterium sp. two genes, namely Bbr_0651 and Bbr_1586, were targeted for insertional inactivation in B. breve UCC2003. As compared to the wild-type, the UCC2003 insertion mutant strains exhibited decreased resistance to gentamycin, kanamycin and streptomycin. This study highlights the associated risks of relying on the in silico assignment of gene function. Although several putative β-lactam resistance proteins are located in bifidobacteria, their presence does not coincide with resistance to these antibiotics. In contrast however, this approach has resulted in the identification of two loci that contribute to the aminoglycoside resistance of B. breve UCC2003 and, potentially, many other bifidobacteria.

  20. Antibiotics and the resistant microbiome

    DEFF Research Database (Denmark)

    Sommer, Morten; Dantas, Gautam

    2011-01-01

    . Less appreciated are the concomitant changes in the human microbiome in response to these assaults and their contribution to clinical resistance problems. Studies have shown that pervasive changes to the human microbiota result from antibiotic treatment and that resistant strains can persist for years....... Additionally, culture-independent functional characterization of the resistance genes from the microbiome has demonstrated a close evolutionary relationship between resistance genes in the microbiome and in pathogens. Application of these techniques and novel cultivation methods are expected to significantly...... expand our understanding of the interplay between antibiotics and the microbiome....

  1. Rhythms of Resistance and Existence

    DEFF Research Database (Denmark)

    Chaudhary, Nandita; Hviid, Pernille; Marsico, Giuseppina

    2017-01-01

    This book is about resistance in everyday life, illustrated through empirical contexts from different parts of the world. Resistance is a widespread phenomenon in biological, social and psychological domains of human cultural development. Yet, it is not well articulated in the academic literature...... occurrence, the focus here is on everyday resistance as an intentional process where new meaning constructions emerge in thinking, feeling, acting or simply living with others. Resistance is thus conceived as a meaning-making activity that operates at the intersection of personal and collective systems...

  2. CONFERENCE REPORT ANTIRETROVIRAL RESISTANCE

    African Journals Online (AJOL)

    2004-08-02

    Aug 2, 2004 ... development of new agents with potential clinical utility for treating resistant ... data on the emergence of resistance among Thai women given zidovudine ... had achieved full virological suppression (viral load. < 50 copies/ml).

  3. Identification of antimicrobial resistance genes in multidrug-resistant clinical Bacteroides fragilis isolates by whole genome shotgun sequencing

    DEFF Research Database (Denmark)

    Sydenham, Thomas Vognbjerg; Sóki, József; Hasman, Henrik

    2015-01-01

    Bacteroides fragilis constitutes the most frequent anaerobic bacterium causing bacteremia in humans. The genetic background for antimicrobial resistance in B. fragilis is diverse with some genes requiring insertion sequence (IS) elements inserted upstream for increased expression. To evaluate whole...... genome shotgun sequencing as a method for predicting antimicrobial resistance properties, one meropenem resistant and five multidrug-resistant blood culture isolates were sequenced and antimicrobial resistance genes and IS elements identified using ResFinder 2.1 (http...

  4. Understanding The Resistance to Health Information Systems

    OpenAIRE

    David Ackah; Angelito E Alvarado; Heru Santoso Wahito Nugroho; Sanglar Polnok; Wiwin Martiningsih

    2017-01-01

    User resistance is users’ opposition to system implementation. Resistance often occurs as a result of a mismatch between management goals and employee preferences. There are two types of resistance to health iformation system namely active resistance and passive resistance. The manifestation of active resistance are being critical,  blaming/accusing, blocking, fault finding, sabotaging, undermining, ridiculing, intimidating/threatening, starting rumors, appealing to fear, manipulating arguing...

  5. Identifying resistance gene analogs associated with resistances to different pathogens in common bean.

    Science.gov (United States)

    López, Camilo E; Acosta, Iván F; Jara, Carlos; Pedraza, Fabio; Gaitán-Solís, Eliana; Gallego, Gerardo; Beebe, Steve; Tohme, Joe

    2003-01-01

    ABSTRACT A polymerase chain reaction approach using degenerate primers that targeted the conserved domains of cloned plant disease resistance genes (R genes) was used to isolate a set of 15 resistance gene analogs (RGAs) from common bean (Phaseolus vulgaris). Eight different classes of RGAs were obtained from nucleotide binding site (NBS)-based primers and seven from not previously described Toll/Interleukin-1 receptor-like (TIR)-based primers. Putative amino acid sequences of RGAs were significantly similar to R genes and contained additional conserved motifs. The NBS-type RGAs were classified in two subgroups according to the expected final residue in the kinase-2 motif. Eleven RGAs were mapped at 19 loci on eight linkage groups of the common bean genetic map constructed at Centro Internacional de Agricultura Tropical. Genetic linkage was shown for eight RGAs with partial resistance to anthracnose, angular leaf spot (ALS) and Bean golden yellow mosaic virus (BGYMV). RGA1 and RGA2 were associated with resistance loci to anthracnose and BGYMV and were part of two clusters of R genes previously described. A new major cluster was detected by RGA7 and explained up to 63.9% of resistance to ALS and has a putative contribution to anthracnose resistance. These results show the usefulness of RGAs as candidate genes to detect and eventually isolate numerous R genes in common bean.

  6. Lack of Cross-Resistance of Imazaquin-Resistant Xanthium strumarium Acetolactate Synthase to Flumetsulam and Chlorimuron.

    Science.gov (United States)

    Schmitzer, P. R.; Eilers, R. J.; Cseke, C.

    1993-09-01

    Acetolactate synthase (ALS) was isolated from a field population of cocklebur (Xanthium strumarium) that developed resistance to the herbicide Scepter following three consecutive years of application. The active ingredient of Scepter, imazaquin, gave an inhibitor concentration required to produce 50% inhibition of the enzyme activity that was more than 300 times greater for the resistant enzyme than for the wild-type cocklebur ALS. Tests with flumetsulam and chlorimuron show that the resistant ALS was not cross-resistant to these two other classes of ALS inhibitors.

  7. Antibiotic resistance in Burkholderia species.

    Science.gov (United States)

    Rhodes, Katherine A; Schweizer, Herbert P

    2016-09-01

    The genus Burkholderia comprises metabolically diverse and adaptable Gram-negative bacteria, which thrive in often adversarial environments. A few members of the genus are prominent opportunistic pathogens. These include Burkholderia mallei and Burkholderia pseudomallei of the B. pseudomallei complex, which cause glanders and melioidosis, respectively. Burkholderia cenocepacia, Burkholderia multivorans, and Burkholderia vietnamiensis belong to the Burkholderia cepacia complex and affect mostly cystic fibrosis patients. Infections caused by these bacteria are difficult to treat because of significant antibiotic resistance. The first line of defense against antimicrobials in Burkholderia species is the outer membrane penetration barrier. Most Burkholderia contain a modified lipopolysaccharide that causes intrinsic polymyxin resistance. Contributing to reduced drug penetration are restrictive porin proteins. Efflux pumps of the resistance nodulation cell division family are major players in Burkholderia multidrug resistance. Third and fourth generation β-lactam antibiotics are seminal for treatment of Burkholderia infections, but therapeutic efficacy is compromised by expression of several β-lactamases and ceftazidime target mutations. Altered DNA gyrase and dihydrofolate reductase targets cause fluoroquinolone and trimethoprim resistance, respectively. Although antibiotic resistance hampers therapy of Burkholderia infections, the characterization of resistance mechanisms lags behind other non-enteric Gram-negative pathogens, especially ESKAPE bacteria such as Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Parasitic resistive switching uncovered from complementary resistive switching in single active-layer oxide memory device

    Science.gov (United States)

    Zhu, Lisha; Hu, Wei; Gao, Chao; Guo, Yongcai

    2017-12-01

    This paper reports the reversible transition processes between the bipolar and complementary resistive switching (CRS) characteristics on the binary metal-oxide resistive memory devices of Pt/HfO x /TiN and Pt/TaO x /TiN by applying the appropriate bias voltages. More interestingly, by controlling the amplitude of the negative bias, the parasitic resistive switching effect exhibiting repeatable switching behavior is uncovered from the CRS behavior. The electrical observation of the parasitic resistive switching effect can be explained by the controlled size of the conductive filament. This work confirms the transformation and interrelationship among the bipolar, parasitic, and CRS effects, and thus provides new insight into the understanding of the physical mechanism of the binary metal-oxide resistive switching memory devices.

  9. Heat-resistant materials

    CERN Document Server

    1997-01-01

    This handbook covers the complete spectrum of technology dealing with heat-resistant materials, including high-temperature characteristics, effects of processing and microstructure on high-temperature properties, materials selection guidelines for industrial applications, and life-assessment methods. Also included is information on comparative properties that allows the ranking of alloy performance, effects of processing and microstructure on high-temperature properties, high-temperature oxidation and corrosion-resistant coatings for superalloys, and design guidelines for applications involving creep and/or oxidation. Contents: General introduction (high-temperature materials characteristics, and mechanical and corrosion properties, and industrial applications); Properties of Ferrous Heat-Resistant Alloys (carbon, alloy, and stainless steels; alloy cast irons; and high alloy cast steels); Properties of superalloys (metallurgy and processing, mechanical and corrosion properties, degradation, and protective coa...

  10. Risk Factors for Acquisition of Drug Resistance during Multidrug-Resistant Tuberculosis Treatment, Arkhangelsk Oblast, Russia, 2005–2010

    Science.gov (United States)

    Ershova, Julia; Vlasova, Natalia; Nikishova, Elena; Tarasova, Irina; Eliseev, Platon; Maryandyshev, Andrey O.; Shemyakin, Igor G.; Kurbatova, Ekaterina; Cegielski, J. Peter

    2015-01-01

    Acquired resistance to antituberculosis drugs decreases effective treatment options and the likelihood of treatment success. We identified risk factors for acquisition of drug resistance during treatment for multidrug-resistant tuberculosis (MDR TB) and evaluated the effect on treatment outcomes. Data were collected prospectively from adults from Arkhangelsk Oblast, Russia, who had pulmonary MDR TB during 2005–2008. Acquisition of resistance to capreomycin and of extensively drug-resistant TB were more likely among patients who received 3 effective drugs (9.4% vs. 0% and 8.6% vs. 0.8%, respectively). Poor outcomes were more likely among patients with acquired capreomycin resistance (100% vs. 25.9%), acquired ofloxacin resistance (83.6% vs. 22.7%), or acquired extensive drug resistance (100% vs. 24.4%). To prevent acquired drug resistance and poor outcomes, baseline susceptibility to first- and second-line drugs should be determined quickly, and treatment should be adjusted to contain >3 effective drugs. PMID:25988954

  11. High temperature resistant cermet and ceramic compositions. [for thermal resistant insulators and refractory coatings

    Science.gov (United States)

    Phillips, W. M. (Inventor)

    1978-01-01

    High temperature oxidation resistance, high hardness and high abrasion and wear resistance are properties of cermet compositions particularly to provide high temperature resistant refractory coatings on metal substrates, for use as electrical insulation seals for thermionic converters. The compositions comprise a sintered body of particles of a high temperature resistant metal or metal alloy, preferably molybdenum or tungsten particles, dispersed in and bonded to a solid solution formed of aluminum oxide and silicon nitride, and particularly a ternary solid solution formed of a mixture of aluminum oxide, silicon nitride and aluminum nitride. Ceramic compositions comprising a sintered solid solution of aluminum oxide, silicon nitride and aluminum nitride are also described.

  12. Electrical Methods: Resistivity Methods

    Science.gov (United States)

    Surface electrical resistivity surveying is based on the principle that the distribution of electrical potential in the ground around a current-carrying electrode depends on the electrical resistivities and distribution of the surrounding soils and rocks.

  13. The update of resist outgas testing for metal containing resists at EIDEC

    Science.gov (United States)

    Shiobara, Eishi; Mikami, Shinji

    2017-10-01

    The metal containing resist is one of the candidates for high sensitivity resists. EIDEC has prepared the infrastructure for outgas testing in hydrogen environment for metal containing resists at High Power EUV irradiation tool (HPEUV). We have experimentally obtained the preliminary results of the non-cleanable metal contamination on witness sample using model material by HPEUV [1]. The metal contamination was observed at only the condition of hydrogen environment. It suggested the generation of volatile metal hydrides by hydrogen radicals. Additionally, the metal contamination on a witness sample covered with Ru was not removed by hydrogen radical cleaning. The strong interaction between the metal hydride and Ru was confirmed by the absorption simulation. Recently, ASML announced a resist outgassing barrier technology using Dynamic Gas Lock (DGL) membrane located between projection optics and wafer stage [2], [3]. DGL membrane blocks the diffusion of all kinds of resist outgassing to the projection optics and prevents the reflectivity loss of EUV mirrors. The investigation of DGL membrane for high volume manufacturing is just going on. It extends the limitation of material design for EUV resists. However, the DGL membrane has an impact for the productivity of EUV scanners due to the transmission loss of EUV light and the necessity of periodic maintenance. The well understanding and control of the outgassing characteristics of metal containing resists may help to improve the productivity of EUV scanner. We consider the outgas evaluation for the resists still useful. For the improvement of resist outgas testing by HPEUV, there are some issues such as the contamination limited regime, the optimization of exposure dose to obtain the measurable contamination film thickness and the detection of minimum amount of metal related outgas species generated. The investigation and improvement for these issues are ongoing. The updates will be presented in the conference. This

  14. Antibiotic resistant pattern of methicillin resistant and sensitive Staphylococcus aureus isolated from patients durining 2009-2010, Ahvaz, Iran.

    Directory of Open Access Journals (Sweden)

    N Parhizgari

    2013-12-01

    Full Text Available Abstract Background & aim: Staphylococcus aureus is one of the most important nosocomial infecting agents resistant to commonly used antibiotics. Nowadays, methicillin-resistant S. aureus (MRSA is considered one of the main causes of nosocomial infections. The aim of this study was to identify the antibiotic resistance pattern of methicicllin- resistant and susceptible strains in Ahwaz, Iran. Methods: In the present cross - sectional study, a number of 255 clinically suspected cases of Staphylococcus aureus were collected during a 19 month period. The bacteria were investigated using standard biochemical tests such as catalase, mannitol fermentation, coagulase and Dnase. Sensitive strains were confirmed by disk diffusion method compared to commonly used antibiotics. The collected data were analyzed using descriptive statistical tests. Results: of 255 suspected cases, 180 were confirmed as S.aureus, a total of 59 strains of S. aureus (2/37 percent were resistant to methicillin. Resistance to S. aureus strains resistant to methicillin included: chloramphenicol (3.38%, rifampin (45.76%, norfloxacin (89.83%, gentamicin (89.83%, ciprofloxacin, (91.52%, azithromycin, (88.13%, cotrimoxazole (86.44% and all isolates strains were sensitive to vancomycin and nitrofurantoin. A total of 10 different patterns of antibiotic resistance in methicillin-resistant Staphylococcus aureus strains were identified. Conclusion: Expression of new resistance factor in nosocomial infection is one of the major challenges in treating these infections. This study showed a high prevalence of resistance against some class of antibiotics in MRSA isolated from Imam Khomeini and Golestan hospital of Ahwaz, Iran. Key words: Nosocomial infection, Methicillin Resistant Staphylococcus aureus (MRSA, Antibiotic Resistant Pattern

  15. The determinants of the antibiotic resistance process.

    Science.gov (United States)

    Franco, Beatriz Espinosa; Altagracia Martínez, Marina; Sánchez Rodríguez, Martha A; Wertheimer, Albert I

    2009-01-01

    The use of antibiotic drugs triggers a complex interaction involving many biological, sociological, and psychological determinants. Resistance to antibiotics is a serious worldwide problem which is increasing and has implications for morbidity, mortality, and health care both in hospitals and in the community. To analyze current research on the determinants of antibiotic resistance and comprehensively review the main factors in the process of resistance in order to aid our understanding and assessment of this problem. We conducted a MedLine search using the key words "determinants", "antibiotic", and "antibiotic resistance" to identify publications between 1995 and 2007 on the determinants of antibiotic resistance. Publications that did not address the determinants of antibiotic resistance were excluded. The process and determinants of antibiotic resistance are described, beginning with the development of antibiotics, resistance and the mechanisms of resistance, sociocultural determinants of resistance, the consequences of antibiotic resistance, and alternative measures proposed to combat antibiotic resistance. Analysis of the published literature identified the main determinants of antibiotic resistance as irrational use of antibiotics in humans and animal species, insufficient patient education when antibiotics are prescribed, lack of guidelines for treatment and control of infections, lack of scientific information for physicians on the rational use of antibiotics, and lack of official government policy on the rational use of antibiotics in public and private hospitals.

  16. Rolling Resistance Measurement and Model Development

    DEFF Research Database (Denmark)

    Andersen, Lasse Grinderslev; Larsen, Jesper; Fraser, Elsje Sophia

    2015-01-01

    There is an increased focus worldwide on understanding and modeling rolling resistance because reducing the rolling resistance by just a few percent will lead to substantial energy savings. This paper reviews the state of the art of rolling resistance research, focusing on measuring techniques, s......, surface and texture modeling, contact models, tire models, and macro-modeling of rolling resistance...

  17. The benefits of herbicide-resistant crops.

    Science.gov (United States)

    Green, Jerry M

    2012-10-01

    Since 1996, genetically modified herbicide-resistant crops, primarily glyphosate-resistant soybean, corn, cotton and canola, have helped to revolutionize weed management and have become an important tool in crop production practices. Glyphosate-resistant crops have enabled the implementation of weed management practices that have improved yield and profitability while better protecting the environment. Growers have recognized their benefits and have made glyphosate-resistant crops the most rapidly adopted technology in the history of agriculture. Weed management systems with glyphosate-resistant crops have often relied on glyphosate alone, have been easy to use and have been effective, economical and more environmentally friendly than the systems they have replaced. Glyphosate has worked extremely well in controlling weeds in glyphosate-resistant crops for more than a decade, but some key weeds have evolved resistance, and using glyphosate alone has proved unsustainable. Now, growers need to renew their weed management practices and use glyphosate with other cultural, mechanical and herbicide options in integrated systems. New multiple-herbicide-resistant crops with resistance to glyphosate and other herbicides will expand the utility of existing herbicide technologies and will be an important component of future weed management systems that help to sustain the current benefits of high-efficiency and high-production agriculture. Copyright © 2012 Society of Chemical Industry.

  18. Strategies for improving rust resistance in oats

    International Nuclear Information System (INIS)

    Harder, D.E.; McKenzie, R.I.H.; Martens, J.W.; Brown, P.D.

    1977-01-01

    During the history of breeding oats for rust resistance in Canada the known sources of resistance proved inadequate to counter the virulence potential of both stem rust (Puccinia graminis avenae) and crown rust (P. coronata avenae). A major programme to overcome the rust problem was undertaken at Winnipeg, involving four alternate approaches: (1) A search for new resistance in wild oat species, particularly Avena sterilis, has provided a wealth of good resistance to crown rust, but less to stem rust. Much of the A. sterilis-derived crown rust resistance is now being used world-wide; (2) Efforts at synthesizing new resistance by mutation breeding methods have not been successful. Of about seven million plants examined, only one showed significant new resistance, but this was associated with poor plant type; (3) Resistance with low levels of expression but which appears broadly effective has been observed against both stem and crown rusts. It appears that numbers of these low-level genes exist, and that they can be accumulated to provide increasingly effective resistance. Problems in using this type of resistance in a practical way are discussed; (4) Excellent rust resistance has been found in lower ploidy species such as A. barbata, but it was not previously possible to stabilize this resistance in hexaploid species. By using mutagenic treatments attempts have been made to translocate smaller portions of the A. barbata chromosome carrying the resistance to the hexaploid cultivar Rodney. In conclusion, mutation breeding methods at present appear to have limited application in synthesizing new rust-resistant genotypes in oats. The search for already existing genetic resistance and its synthesis into multi-genic resistant lines appears to be the most effective way at present of resolving the rust problem in oats. (author)

  19. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... how antimicrobial resistance both emerges and proliferates among bacteria. Over time, the use of antimicrobial drugs will result in the development of resistant strains of bacteria, complicating clinician's efforts to select the appropriate antimicrobial ...

  20. Candida Species Biofilms’ Antifungal Resistance

    Science.gov (United States)

    Silva, Sónia; Rodrigues, Célia F.; Araújo, Daniela; Rodrigues, Maria Elisa; Henriques, Mariana

    2017-01-01

    Candida infections (candidiasis) are the most prevalent opportunistic fungal infection on humans and, as such, a major public health problem. In recent decades, candidiasis has been associated to Candida species other than Candida albicans. Moreover, biofilms have been considered the most prevalent growth form of Candida cells and a strong causative agent of the intensification of antifungal resistance. As yet, no specific resistance factor has been identified as the sole responsible for the increased recalcitrance to antifungal agents exhibited by biofilms. Instead, biofilm antifungal resistance is a complex multifactorial phenomenon, which still remains to be fully elucidated and understood. The different mechanisms, which may be responsible for the intrinsic resistance of Candida species biofilms, include the high density of cells within the biofilm, the growth and nutrient limitation, the effects of the biofilm matrix, the presence of persister cells, the antifungal resistance gene expression and the increase of sterols on the membrane of biofilm cells. Thus, this review intends to provide information on the recent advances about Candida species biofilm antifungal resistance and its implication on intensification of the candidiasis. PMID:29371527