Virulence of the Phytopathogen Pseudomonas syringae pv. Maculicola Is rpoN Dependent

Science.gov (United States)

Hendrickson, Erik L.; Guevera, Pablo; Peñaloza-Vàzquez, Alejandro; Shao, Jing; Bender, Carol; Ausubel, Frederick M.

2000-01-01

We cloned the rpoN (ntrA and glnF) gene encoding ς54 from the phytopathogen Pseudomonas syringae pv. maculicola strain ES4326. The P. syringae ES4326 rpoN gene complemented Pseudomonas aeruginosa, Escherichia coli, and Klebsiella aerogenes rpoN mutants for a variety of rpoN mutant phenotypes, including the inability to utilize nitrate as sole nitrogen source. DNA sequence analysis of the P. syringae ES4326 rpoN gene revealed that the deduced amino acid sequence was most similar (86% identity; 95% similarity) to the ς54 protein encoded by the Pseudomonas putida rpoN gene. A marker exchange protocol was used to construct an ES4326 rpoN insertional mutation, rpoN::Kmr. In contrast to wild-type ES4326, ES4326 rpoN::Kmr was nonmotile and could not utilize nitrate, urea, C4-dicarboxylic acids, several amino acids, or concentrations of ammonia below 2 mM as nitrogen sources. rpoN was essential for production of the phytotoxin coronatine and for expression of the structural genes encoding coronamic acid. In addition, ES4326 rpoN::Kmr did not multiply or elicit disease symptoms when infiltrated into Arabidopsis thaliana leaves, did not elicit the accumulation of several Arabidopsis defense-related mRNAs, and did not elicit a hypersensitive response (HR) when infiltrated into tobacco (Nicotiana tabacum) leaves. Furthermore, whereas P. syringae ES4326 carrying the avirulence gene avrRpt2 elicited an HR when infiltrated into Arabidopsis ecotype Columbia leaves, ES4326 rpoN::Kmr carrying avrRpt2 elicited no response. Constitutive expression of ES4326 hrpL in ES4326 rpoN::Kmr partially restored defense-related mRNA accumulation, showing a direct role for the hrp cluster in host defense gene induction in a compatible host-pathogen interaction. However, constitutive expression of hrpL in ES4326 rpoN::Kmr did not restore coronatine production, showing that coronatine biosynthesis requires factors other than hrpL. PMID:10852883

Characterisation of the mgo operon in Pseudomonas syringae pv. syringae UMAF0158 that is required for mangotoxin production

Science.gov (United States)

2012-01-01

Background Mangotoxin is an antimetabolite toxin that is produced by strains of Pseudomonas syringae pv. syringae; mangotoxin-producing strains are primarily isolated from mango tissues with symptoms of bacterial apical necrosis. The toxin is an oligopeptide that inhibits ornithine N-acetyl transferase (OAT), a key enzyme in the biosynthetic pathway of the essential amino acids ornithine and arginine. The involvement of a putative nonribosomal peptide synthetase gene (mgoA) in mangotoxin production and virulence has been reported. Results In the present study, we performed a RT-PCR analysis, insertional inactivation mutagenesis, a promoter expression analysis and terminator localisation to study the gene cluster containing the mgoA gene. Additionally, we evaluated the importance of mgoC, mgoA and mgoD in mangotoxin production. A sequence analysis revealed an operon-like organisation. A promoter sequence was located upstream of the mgoB gene and was found to drive lacZ transcription. Two terminators were located downstream of the mgoD gene. RT-PCR experiments indicated that the four genes (mgoBCAD) constitute a transcriptional unit. This operon is similar in genetic organisation to those in the three other P. syringae pathovars for which complete genomes are available (P. syringae pv. syringae B728a, P. syringae pv. tomato DC3000 and P. syringae pv. phaseolicola 1448A). Interestingly, none of these three reference strains is capable of producing mangotoxin. Additionally, extract complementation resulted in a recovery of mangotoxin production when the defective mutant was complemented with wild-type extracts. Conclusions The results of this study confirm that mgoB, mgoC, mgoA and mgoD function as a transcriptional unit and operon. While this operon is composed of four genes, only the last three are directly involved in mangotoxin production. PMID:22251433

A Mathematical model to investigate quorum sensing regulation and its heterogenecity in pseudomonas syringae on leaves

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The bacterium Pseudomonas syringae is a plant-pathogen, which through quorum sensing (QS), controls virulence. In this paper, by means of mathematical modeling, we investigate QS of this bacterium when living on leaf surfaces. We extend an existing stochastic model for the formation of Pseudomonas s...

Flagellar motility confers epiphytic fitness advantages upon Pseudomonas syringae

International Nuclear Information System (INIS)

Haefele, D.M.; Lindow, S.E.

1987-01-01

The role of flagellar motility in determining the epiphytic fitness of an ice-nucleation-active strain of Pseudomonas syringae was examined. The loss of flagellar motility reduced the epiphytic fitness of a normally motile P. syringae strain as measured by its growth, survival, and competitive ability on bean leaf surfaces. Equal population sizes of motile parental or nonmotile mutant P. syringae strains were maintained on bean plants for at least 5 days following the inoculation of fully expanded primary leaves. However, when bean seedlings were inoculated before the primary leaves had expanded and bacterial populations on these leaves were quantified at full expansion, the population size of the nonmotile derivative strain reached only 0.9% that of either the motile parental or revertant strain. When fully expanded bean primary leaves were coinoculated with equal numbers of motile and nonmotile cells, the population size of a nonmotile derivative strain was one-third of that of the motile parental or revertant strain after 8 days. Motile and nonmotile cells were exposed in vitro and on plants to UV radiation and desiccating conditions. The motile and nonmotile strains exhibited equal resistance to both stresses in vitro. However, the population size of a nonmotile strain on leaves was less than 20% that of a motile revertant strain when sampled immediately after UV irradiation. Epiphytic populations of both motile and nonmotile P. syringae declined under desiccating conditions on plants, and after 8 days, the population size of a nonmotile strain was less than one-third that of the motile parental or revertant strain

Dual Effect of the Cubic Ag₃PO₄ Crystal on Pseudomonas syringae Growth and Plant Immunity

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Mi Kyung Kim

2016-04-01

Full Text Available We previously found that the antibacterial activity of silver phosphate crystals on Escherichia coli depends on their structure. We here show that the cubic form of silver phosphate crystal (SPC can also be applied to inhibit the growth of a plant-pathogenic Pseudomonas syringae bacterium. SPC pretreatment resulted in reduced in planta multiplication of P. syringae. Induced expression of a plant defense marker gene PR1 by SPC alone is suggestive of its additional plant immunity-stimulating activity. Since SPC can simultaneously inhibit P. syringae growth and induce plant defense responses, it might be used as a more effective plant disease-controlling agent.

The Facultative Symbiont Rickettsia Protects an Invasive Whitefly against Entomopathogenic Pseudomonas syringae Strains.

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Hendry, Tory A; Hunter, Martha S; Baltrus, David A

2014-12-01

Facultative endosymbionts can benefit insect hosts in a variety of ways, including context-dependent roles, such as providing defense against pathogens. The role of some symbionts in defense may be overlooked, however, when pathogen infection is transient, sporadic, or asymptomatic. The facultative endosymbiont Rickettsia increases the fitness of the sweet potato whitefly (Bemisia tabaci) in some populations through mechanisms that are not yet understood. In this study, we investigated the role of Rickettsia in mediating the interaction between the sweet potato whitefly and Pseudomonas syringae, a common environmental bacterium, some strains of which are pathogenic to aphids. Our results show that P. syringae multiplies within whiteflies, leading to host death, and that whiteflies infected with Rickettsia show a decreased rate of death due to P. syringae. Experiments using plants coated with P. syringae confirmed that whiteflies can acquire the bacteria at a low rate while feeding, leading to increased mortality, particularly when the whiteflies are not infected with Rickettsia. These results suggest that P. syringae may affect whitefly populations in nature and that Rickettsia can ameliorate this effect. This study highlights the possible importance of interactions among opportunistic environmental pathogens and endosymbionts of insects. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Verspreiding, diversiteit en activiteit van antibioticaproducerende Pseudomonas spp

NARCIS (Netherlands)

Souza, J.T.

2003-01-01

Pseudomonas bacteriën zijn potentiële antagonisten van diverse plantenpathogene schimmels en oömyceten. De productie van antibiotica speelt een belangrijke rol in de activiteit van diverse Pseudomonas isolaten tegen plantenpathogenen. Dit artikel is een samenvatting van het proefschrift getiteld

BOX-PCR-based identification of bacterial species belonging to Pseudomonas syringae: P. viridiflava group

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Abi S.A. Marques

2008-01-01

Full Text Available The phenotypic characteristics and genetic fingerprints of a collection of 120 bacterial strains, belonging to Pseudomonas syringae sensu lato group, P. viridiflava and reference bacteria were evaluated, with the aim of species identification. The numerical analysis of 119 nutritional characteristics did not show patterns that would help with identification. Regarding the genetic fingerprinting, the results of the present study supported the observation that BOX-PCR seems to be able to identify bacterial strains at species level. After numerical analyses of the bar-codes, all pathovars belonging to each one of the nine described genomospecies were clustered together at a distance of 0.72, and could be separated at genomic species level. Two P. syringae strains of unknown pathovars (CFBP 3650 and CFBP 3662 and the three P. syringae pv. actinidiae strains were grouped in two extra clusters and might eventually constitute two new species. This genomic species clustering was particularly evident for genomospecies 4, which gathered P. syringae pvs. atropurpurea, coronafaciens, garçae, oryzae, porri, striafaciens, and zizaniae at a noticeably low distance.

Contribution of alginate and levan production to biofilm formation by Pseudomonas syringae

DEFF Research Database (Denmark)

Laue, H.; Schenk, A.; Li, H.

2006-01-01

formation, biofilms of Pseudomonas syringae strains with different EPS patterns were compared. The mucoid strain PG4180.muc, which produces levan and alginate, and its levan- and/or alginate-deficient derivatives all formed biofilms in the wells of microtitre plates and in flow chambers. Confocal laser...... by binding of the lectin from Naja mossambica to a fibrous structure in biofilms of all P. syringae derivatives. Production of the as yet uncharacterized additional EPS might be more important for biofilm formation than the syntheses of levan and alginate.......Exopolysaccharides (EPSs) play important roles in the attachment of bacterial cells to a surface and/or in building and maintaining the three-dimensional, complex structure of bacterial biofilms. To elucidate the spatial distribution and function of the EPSs levan and alginate during biofilm...

HOPM1 mediated disease resistance to Pseudomonas syringae in Arabidopsis

Science.gov (United States)

He, Sheng Yang [Okemos, MI; Nomura, Kinya [East Lansing, MI

2011-11-15

The present invention relates to compositions and methods for enhancing plant defenses against pathogens. More particularly, the invention relates to enhancing plant immunity against bacterial pathogens, wherein HopM1.sub.1-300 mediated protection is enhanced, such as increased protection to Pseudomonas syringae pv. tomato DC3000 HopM1 and/or there is an increase in activity of an ATMIN associated plant protection protein, such as ATMIN7. Reagents of the present invention further provide a means of studying cellular trafficking while formulations of the present inventions provide increased pathogen resistance in plants.

AtMIN7 mediated disease resistance to Pseudomonas syringae in Arabidopsis

Science.gov (United States)

He, Sheng Yang [Okemos, MI; Nomura, Kinya [East Lansing, MI

2011-07-26

The present invention relates to compositions and methods for enhancing plant defenses against pathogens. More particularly, the invention relates to enhancing plant immunity against bacterial pathogens, wherein AtMIN7 mediated protection is enhanced and/or there is a decrease in activity of an AtMIN7 associated virulence protein such as a Pseudomonas syringae pv. tomato DC3000 HopM1. Reagents of the present invention provide a means of studying cellular trafficking while formulations of the present inventions provide increased pathogen resistance in plants.

Thermo-Regulation of Genes Mediating Motility and Plant Interactions in Pseudomonas syringae

Science.gov (United States)

Hockett, Kevin L.; Burch, Adrien Y.; Lindow, Steven E.

2013-01-01

Pseudomonas syringae is an important phyllosphere colonist that utilizes flagellum-mediated motility both as a means to explore leaf surfaces, as well as to invade into leaf interiors, where it survives as a pathogen. We found that multiple forms of flagellum-mediated motility are thermo-suppressed, including swarming and swimming motility. Suppression of swarming motility occurs between 28° and 30°C, which coincides with the optimal growth temperature of P. syringae. Both fliC (encoding flagellin) and syfA (encoding a non-ribosomal peptide synthetase involved in syringafactin biosynthesis) were suppressed with increasing temperature. RNA-seq revealed 1440 genes of the P. syringae genome are temperature sensitive in expression. Genes involved in polysaccharide synthesis and regulation, phage and IS elements, type VI secretion, chemosensing and chemotaxis, translation, flagellar synthesis and motility, and phytotoxin synthesis and transport were generally repressed at 30°C, while genes involved in transcriptional regulation, quaternary ammonium compound metabolism and transport, chaperone/heat shock proteins, and hypothetical genes were generally induced at 30°C. Deletion of flgM, a key regulator in the transition from class III to class IV gene expression, led to elevated and constitutive expression of fliC regardless of temperature, but did not affect thermo-regulation of syfA. This work highlights the importance of temperature in the biology of P. syringae, as many genes encoding traits important for plant-microbe interactions were thermo-regulated. PMID:23527276

Inhibition of apoptic cell death induced by Pseudomonas syringae pv. Tabaci and mycotoxin fumonisin B1

NARCIS (Netherlands)

Iakimova, E.T.; Batchvorova, R.; Kapchina, V.; Popov, T.; Atanassov, A.; Woltering, E.J.

2004-01-01

The impact of programmed cell death (PCD) inhibitors on lesion formation and biochemical events in transgenic (ttr line) and non-transgenic (Nevrokop 1164) tobacco infected with Pseudomonas syringae pv. tabaci was tested. Programmed cell death in tomato cell culture was induced by Fumonisin B1 (FUM)

Characterization of five ECF sigma factors in the genome of Pseudomonas syringae pv. syringae B728a.

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Poulami Basu Thakur

Full Text Available Pseudomonas syringae pv. syringae B728a, a bacterial pathogen of bean, utilizes large surface populations and extracellular signaling to initiate a fundamental change from an epiphytic to a pathogenic lifestyle. Extracytoplasmic function (ECF sigma (σ factors serve as important regulatory factors in responding to various environmental signals. Bioinformatic analysis of the B728a genome revealed 10 ECF sigma factors. This study analyzed deletion mutants of five previously uncharacterized ECF sigma factor genes in B728a, including three FecI-type ECF sigma factors (ECF5, ECF6, and ECF7 and two ECF sigma factors placed in groups ECF11 and ECF18. Transcriptional profiling by qRT-PCR analysis of ECF sigma factor mutants was used to measure expression of their associated anti-sigma and outer membrane receptor proteins, and expression of genes associated with production of extracellular polysaccharides, fimbriae, glycine betaine and syringomycin. Notably, the B728aΔecf7 mutant displayed reduced swarming and had decreased expression of CupC fimbrial genes. Growth and pathogenicity assays, using a susceptible bean host, revealed that none of the tested sigma factor genes are required for in planta growth and lesion formation.

Pseudomonas syringae pv. actinidiae: a re-emerging, multi-faceted, pandemic pathogen.

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Scortichini, Marco; Marcelletti, Simone; Ferrante, Patrizia; Petriccione, Milena; Firrao, Giuseppe

2012-09-01

Pseudomonas syringae pv. actinidiae is the causal agent of bacterial canker of green-fleshed kiwifruit (Actinidia deliciosa) and yellow-fleshed kiwifruit (A. chinensis). A recent, sudden, re-emerging wave of this disease has occurred, almost contemporaneously, in all of the main areas of kiwifruit production in the world, suggesting that it can be considered as a pandemic disease. Recent in-depth genetic studies performed on P. syringae pv. actinidiae strains have revealed that this pathovar is composed of four genetically different populations which, to different extents, can infect crops of the genus Actinidia worldwide. Genome comparisons of these strains have revealed that this pathovar can gain and lose the phaseolotoxin gene cluster, as well as mobile genetic elements, such as plasmids and putative prophages, and that it can modify the repertoire of the effector gene arrays. In addition, the strains currently causing worldwide severe economic losses display an extensive set of genes related to the ecological fitness of the bacterium in planta, such as copper and antibiotic resistance genes, multiple siderophore genes and genes involved in the degradation of lignin derivatives and other phenolics. This pathogen can therefore easily colonize hosts throughout the year. Bacteria; Proteobacteria, gamma subdivision; Order Pseudomonadales; Family Pseudomonadaceae; Genus Pseudomonas; Pseudomonas syringae species complex, genomospecies 8; Pathovar actinidiae. Gram-negative, aerobic, motile, rod-shaped, polar flagella, oxidase-negative, arginine dihydrolase-negative, DNA 58.5-58.8 mol.% GC, elicits the hypersensitive response on tobacco leaves. Primarily studied as the causal agent of bacterial canker of green-fleshed kiwifruit (Actinidia deliciosa), it has also been isolated from yellow-fleshed kiwifruit (A. chinensis). In both species, it causes severe economic losses worldwide. It has also been isolated from wild A. arguta and A. kolomikta. In green-fleshed and

Virulence of Pseudomonas syringae pv. tomato DC3000 is modulated through the Catabolite Repression Control protein Crc

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Pseudomonas syringae (P.s.) infects diverse plant species and several P.s. pathovars have been used in the study of molecular events that occur during plant-microbe interactions. Although the relationship between bacterial metabolism, nutrient acquisition and virulence has attracted increasing atten...

The life history of Pseudomonas syringae: linking agriculture to earth system processes.

Science.gov (United States)

Morris, Cindy E; Monteil, Caroline L; Berge, Odile

2013-01-01

The description of the ecology of Pseudomonas syringae is moving away from that of a ubiquitous epiphytic plant pathogen to one of a multifaceted bacterium sans frontières in fresh water and other ecosystems linked to the water cycle. Discovery of the aquatic facet of its ecology has led to a vision of its life history that integrates spatial and temporal scales spanning billions of years and traversing catchment basins, continents, and the planet and that confronts the implication of roles that are potentially conflicting for agriculture (as a plant pathogen and as an actor in processes leading to rain and snowfall). This new ecological perspective has also yielded insight into epidemiological phenomena linked to disease emergence. Overall, it sets the stage for the integration of more comprehensive contexts of ecology and evolutionary history into comparative genomic analyses to elucidate how P. syringae subverts the attack and defense responses of the cohabitants of the diverse environments it occupies.

Conductimetric detection of Pseudomonas syringae pathover pisi in pea seeds and soft rot Erwinia spp. on potato tubers

NARCIS (Netherlands)

Fraaije, B.

1996-01-01

Pea bacterial blight and potato blackleg are diseases caused by Pseudomonas syringae pv. pisi ( Psp ) and soft rot Erwinia spp., respectively. The primary source of inoculum for these bacteria is

Pathovars of Pseudomonas syringae Causing Bacterial Brown Spot and Halo Blight in Phaseolus vulgaris L. Are Distinguishable by Ribotyping

Science.gov (United States)

González, Ana J.; Landeras, Elena; Mendoza, M. Carmen

2000-01-01

Ribotyping was evaluated as a method to differentiate between Pseudomonas syringae pv. phaseolicola and pv. syringae strains causing bacterial brown spot and halo blight diseases in Phaseolus vulgaris L. Ribotyping, with restriction enzymes BglI and SalI and using the Escherichia coli rrnB operon as the probe, differentiated 11 and 14 ribotypes, respectively, and a combination of data from both procedures yielded 19 combined ribotypes. Cluster analysis of the combined ribotypes differentiated the pathovars phaseolicola and syringae, as well as different clonal lineages within these pathovars. The potential of ribotyping to screen for correlations between lineages and factors such as geographical region and/or bean varieties is also reported. PMID:10653764

The role of crop waste and soil in Pseudomonas syringae pathovar porri infection of leek (Allium porrum)

NARCIS (Netherlands)

Overbeek, van L.S.; Nijhuis, E.H.; Koenraadt, H.; Visser, J.H.M.

2010-01-01

Pseudomonas syringae pv. porri, the causal agent of bacterial blight of leek, is a current threat for leek (Allium porrum) production in the Netherlands. The roles of post-harvest crop waste and plant invasion from soil in leek plant infection was investigated with the purpose to gain better

Genome-wide DNA binding pattern of two-component system response regulator RhpR in Pseudomonas syringae

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Tianhong Zhou

2015-06-01

Full Text Available Although Pseudomonas syringae uses the two-component system RhpRS to modulate the expression of type III secretion system (T3SS genes and pathogenicity, the molecular mechanisms and the regulon of RhpRS have yet to be fully demonstrated. We have performed a genome-wide analysis of RhpR binding to DNA prepared from P. syringae pv. phaseolicola in order to identify candidate direct targets of RhpR-mediated transcriptional regulation, as described in our recent article [1]. The data are available from NCBI Gene Expression Omnibus (GEO with the accession number GSE58533. Here we describe the detailed methods and data analyses of our RhpR ChIP-seq dataset.

Biosynthesis and regulation of coronatine, a non-host-specific phytotoxin produced by Pseudomonas syringae.

Science.gov (United States)

Bender, C L; Palmer, D A; Peñaloza-Vázquez, A; Rangaswamy, V; Ullrich, M

1998-01-01

Pseudomonas when sufficient sequence information is available. It is important to note that Pseudomonas produces a variety of antimicrobial compounds from the polyketide pathway, including mupirocin (pseudomonic acid) (Feline et al., 1977), pyoluteorin (Cuppels et al., 1986), and 2-4 diacetylphloroglucinol (Phl) (Bangera and Thomashow, 1996). Pseudomonic acid is valued for its pharmaceutical properties as an antibiotic (Aldridge, 1992), whereas pyoluteorin and Phl have antifungal properties (Howell and Stipanovic, 1980; Keel et al., 1992). A thorough understanding of the biosynthetic pathway to polyketide phytotoxins such as coronatine may ultimately lead to the development of novel compounds with altered biological properties. Thus, specific genes in the biosynthetic pathways of P. syringae phytotoxins could be deployed in other systems to develop new compounds with a wide range of activities.

Pseudomonas syringae evades host Immunity by degrading flagellin monomers with alkaline protease AprA

OpenAIRE

Pel, M.J.C.; Van Dijken, A.J.H.; Bardoel, B.W.; Seidl, M.F; Van der Ent, S.; Van Strijp, J.A.G.

2014-01-01

Bacterial flagellin molecules are strong inducers of innate immune responses in both mammals and plants. The opportunistic pathogen Pseudomonas aeruginosa secretes an alkaline protease called AprA that degrades flagellin monomers. Here, we show that AprA is widespread among a wide variety of bacterial species. In addition, we investigated the role of AprA in virulence of the bacterial plant athogen P. syringae pv. tomato DC3000. The AprA-deficient DC3000 ΔaprA knockout mutant was significantl...

Inhibitory effect of Thymus vulgaris and Origanum vulgare essential oils on virulence factors of phytopathogenic Pseudomonas syringae strains.

Science.gov (United States)

Carezzano, M E; Sotelo, J P; Primo, E; Reinoso, E B; Paletti Rovey, M F; Demo, M S; Giordano, W F; Oliva, M de Las M

2017-07-01

Pseudomonas syringae is a phytopathogenic bacterium that causes lesions in leaves during the colonisation process. The damage is associated with production of many virulence factors, such as biofilm and phytotoxins. The essential oils of Thymus vulgaris (thyme) and Origanum vulgare (oregano) have been demonstrated to inhibit P. syringae. The aim of this study was to investigate the effects of T. vulgaris and O. vulgare essential oils on production of virulence factors of phytopathogenic P. syringae strains, including anti-biofilm and anti-toxins activities. The broth microdilution method was used for determination of MIC and biofilm inhibition assays. Coronatine, syringomycin and tabtoxin were pheno- and genotypically evaluated. Both oils showed good inhibitory activity against P. syringae, with MIC values from 1.43 to 11.5 mg·ml -1 for thyme and 5.8 to 11.6 mg·ml -1 for oregano. Biofilm formation, production of coronatine, syringomycin and tabtoxin were inhibited by thyme and oregano essential oil in most strains. The results presented here are promising, demonstrating the bactericidal activity and reduction of virulence factor production after treatment with thyme and oregano oil, providing insight into how they exert their antibacterial activity. These natural products could be considered in the future for the control of diseases caused by P. syringae. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

Entomopathogenicity to Two Hemipteran Insects Is Common but Variable across Epiphytic Pseudomonas syringae Strains.

Science.gov (United States)

Smee, Melanie R; Baltrus, David A; Hendry, Tory A

2017-01-01

Strains of the well-studied plant pathogen Pseudomonas syringae show large differences in their ability to colonize plants epiphytically and to inflict damage to hosts. Additionally, P. syringae can infect some sap-sucking insects and at least one P. syringae strain is highly virulent to insects, causing death to most individuals within as few as 4 days and growing to high population densities within insect hosts. The likelihood of agricultural pest insects coming into contact with transient populations of P. syringae while feeding on plants is high, yet the ecological implications of these interactions are currently not well understood as virulence has not been tested across a wide range of strains. To investigate virulence differences across strains we exposed the sweet potato whitefly, Bemisia tabaci , and the pea aphid, Acyrthosiphon pisum , both of which are cosmopolitan agricultural pests, to 12 P. syringae strains. We used oral inoculations with bacteria suspended in artificial diet in order to assay virulence while controlling for other variables such as differences in epiphytic growth ability. Generally, patterns of pathogenicity remain consistent across the two species of hemipteran insects, with bacterial strains from phylogroup II, or genomospecies 1, causing the highest rate of mortality with up to 86% of individuals dead after 72 h post infection. The rate of mortality is highly variable across strains, some significantly different from negative control treatments and others showing no discernable difference. Interestingly, one of the most pathogenic strains to both aphids and whiteflies (Cit7) is thought to be non-pathogenic on plants. We also found Cit7 to establish the highest epiphytic population after 48 h on fava beans. Between the nine P. syringae strains tested for epiphytic ability there is also much variation, but epiphytic ability was positively correlated with pathogenicity to insects, suggesting that the two traits may be linked and that

Entomopathogenicity to Two Hemipteran Insects Is Common but Variable across Epiphytic Pseudomonas syringae Strains

Directory of Open Access Journals (Sweden)

Melanie R. Smee

2017-12-01

Full Text Available Strains of the well-studied plant pathogen Pseudomonas syringae show large differences in their ability to colonize plants epiphytically and to inflict damage to hosts. Additionally, P. syringae can infect some sap-sucking insects and at least one P. syringae strain is highly virulent to insects, causing death to most individuals within as few as 4 days and growing to high population densities within insect hosts. The likelihood of agricultural pest insects coming into contact with transient populations of P. syringae while feeding on plants is high, yet the ecological implications of these interactions are currently not well understood as virulence has not been tested across a wide range of strains. To investigate virulence differences across strains we exposed the sweet potato whitefly, Bemisia tabaci, and the pea aphid, Acyrthosiphon pisum, both of which are cosmopolitan agricultural pests, to 12 P. syringae strains. We used oral inoculations with bacteria suspended in artificial diet in order to assay virulence while controlling for other variables such as differences in epiphytic growth ability. Generally, patterns of pathogenicity remain consistent across the two species of hemipteran insects, with bacterial strains from phylogroup II, or genomospecies 1, causing the highest rate of mortality with up to 86% of individuals dead after 72 h post infection. The rate of mortality is highly variable across strains, some significantly different from negative control treatments and others showing no discernable difference. Interestingly, one of the most pathogenic strains to both aphids and whiteflies (Cit7 is thought to be non-pathogenic on plants. We also found Cit7 to establish the highest epiphytic population after 48 h on fava beans. Between the nine P. syringae strains tested for epiphytic ability there is also much variation, but epiphytic ability was positively correlated with pathogenicity to insects, suggesting that the two traits may be

Atmospheric CO2 Alters Resistance of Arabidopsis to Pseudomonas syringae by Affecting Abscisic Acid Accumulation and Stomatal Responsiveness to Coronatine

NARCIS (Netherlands)

Zhou, Y.; Vroegop-Vos, I.; Schuurink, R.C.; Pieterse, C.M.J.; Van Wees, S.C.M.

Atmospheric CO2 influences plant growth and stomatal aperture. Effects of high or low CO2 levels on plant disease resistance are less well understood. Here, resistance of Arabidopsis thaliana against the foliar pathogen Pseudomonas syringae pv. tomato DC3000 (Pst) was investigated at three different

CBL-interacting protein kinase 6 negatively regulates immune response to Pseudomonas syringae in Arabidopsis.

Science.gov (United States)

Sardar, Atish; Nandi, Ashis Kumar; Chattopadhyay, Debasis

2017-06-15

Cytosolic calcium ion (Ca2+) is an essential mediator of the plant innate immune response. Here, we report that a calcium-regulated protein kinase Calcineurin B-like protein (CBL)-interacting protein kinase 6 (CIPK6) functions as a negative regulator of immunity against the bacterial pathogen Pseudomonas syringae in Arabidopsis thaliana. Arabidopsis lines with compromised expression of CIPK6 exhibited enhanced disease resistance to the bacterial pathogen and to P. syringae harboring certain but not all avirulent effectors, while restoration of CIPK6 expression resulted in abolition of resistance. Plants overexpressing CIPK6 were more susceptible to P. syringae. Enhanced resistance in the absence of CIPK6 was accompanied by increased accumulation of salicylic acid and elevated expression of defense marker genes. Salicylic acid accumulation was essential for improved immunity in the absence of CIPK6. CIPK6 negatively regulated the oxidative burst associated with perception of pathogen-associated microbial patterns (PAMPs) and bacterial effectors. Accelerated and enhanced activation of the mitogen-activated protein kinase cascade in response to bacterial and fungal elicitors was observed in the absence of CIPK6. The results of this study suggested that CIPK6 negatively regulates effector-triggered and PAMP-triggered immunity in Arabidopsis. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Abscisic acid-cytokinin antagonism modulates resistance against pseudomonas syringae in Tobacco

DEFF Research Database (Denmark)

Grosskinsky, Dominik Kilian; van der Graaff, Eric; Roitsch, Thomas Georg

2014-01-01

Phytohormones are known as essential regulators of plant defenses, with ethylene, jasmonic acid, and salicylic acid as the central immunity backbone, while other phytohormones have been demonstrated to interact with this. Only recently, a function of the classic phytohormone cytokinin in plant...... immunity has been described in Arabidopsis, rice, and tobacco. Although interactions of cytokinins with salicylic acid and auxin have been indicated, the complete network of cytokinin interactions with other immunity-relevant phytohormones is not yet understood. Therefore, we studied the interaction...... of kinetin and abscisic acid as a negative regulator of plant immunity to modulate resistance in tobacco against Pseudomonas syringae. By analyzing infection symptoms, pathogen proliferation, and accumulation of the phytoalexin scopoletin as a key mediator of kinetin-induced resistance in tobacco...

The Arabidopsis thaliana non-specific phospholipase C2 is involved in the response to Pseudomonas syringae attack

Czech Academy of Sciences Publication Activity Database

Krčková, Zuzana; Kocourková, Daniela; Daněk, Michal; Brouzdová, Jitka; Pejchar, Přemysl; Janda, Martin; Pokotylo, I.; Ott, P.G.; Valentová, O.; Martinec, Jan

2018-01-01

Roč. 121, č. 2 (2018), s. 297-310 ISSN 0305-7364 R&D Projects: GA ČR(CZ) GAP501/12/1942 Institutional support: RVO:61389030 Keywords : Arabidopsis thaliana * effector-triggered immunity * flagellin * MAMP-triggered immunity * non-specific phospholipase C * phosphatidylcholine-specific phospholipase C * Pseudomonas syringae * reactive oxygen species Subject RIV: ED - Physiology OBOR OECD: Plant sciences, botany Impact factor: 4.041, year: 2016

Genotypische diversiteit en rhizosfeerkolonisatie van DAPG-producerende Pseudomonas spp.

NARCIS (Netherlands)

Bergsma-Vlami, M.

2009-01-01

Het antibioticum 2,4-diacetylphloroglucinol (DAPG) speelt een belangrijke rol in biologische bestrijding van verschillende plantenpathogenen door fluorescerende Pseudomonas-soorten. DAPG-producerende Pseudomonas-stammen zijn effectief in biologische bestrijding, maar hun saprofytisch vermogen is

First report of bacterial speck of tomato caused by Pseudomonas syringae pv. tomato race 1 in Portugal

OpenAIRE

Cruz, L.; Cruz, J.; Eloy, M.; Oliveira, Helena; Vaz, H.; Tenreiro, R.

2010-01-01

Protected and open field tomato crops are economically important for Portuguese agriculture. In 1983, Pseudomonas syringae pv. tomato (Okabe, 1933) Young, Dye & Wilkie, 1978 was first reported affecting protected crops (3) and then later under open field conditions (1). In the 2009 spring/summer season, several outbreaks of bacterial speck of tomato showing an unusual degree of severity were observed in open fields from the Tagus Valley Region

The mangotoxin biosynthetic operon (mbo) is specifically distributed within Pseudomonas syringae genomospecies 1 and was acquired only once during evolution.

Science.gov (United States)

Carrión, Víctor J; Gutiérrez-Barranquero, José A; Arrebola, Eva; Bardaji, Leire; Codina, Juan C; de Vicente, Antonio; Cazorla, Francisco M; Murillo, Jesús

2013-02-01

Mangotoxin production was first described in Pseudomonas syringae pv. syringae strains. A phenotypic characterization of 94 P. syringae strains was carried out to determine the genetic evolution of the mangotoxin biosynthetic operon (mbo). We designed a PCR primer pair specific for the mbo operon to examine its distribution within the P. syringae complex. These primers amplified a 692-bp DNA fragment from 52 mangotoxin-producing strains and from 7 non-mangotoxin-producing strains that harbor the mbo operon, whereas 35 non-mangotoxin-producing strains did not yield any amplification. This, together with the analysis of draft genomes, allowed the identification of the mbo operon in five pathovars (pathovars aptata, avellanae, japonica, pisi, and syringae), all of which belong to genomospecies 1, suggesting a limited distribution of the mbo genes in the P. syringae complex. Phylogenetic analyses using partial sequences from housekeeping genes differentiated three groups within genomospecies 1. All of the strains containing the mbo operon clustered in groups I and II, whereas those lacking the operon clustered in group III; however, the relative branching order of these three groups is dependent on the genes used to construct the phylogeny. The mbo operon maintains synteny and is inserted in the same genomic location, with high sequence conservation around the insertion point, for all the strains in groups I and II. These data support the idea that the mbo operon was acquired horizontally and only once by the ancestor of groups I and II from genomospecies 1 within the P. syringae complex.

Self-protection of Pseudomonas syringae pv. tabaci from its toxin, tabtoxinine-β-lactam

International Nuclear Information System (INIS)

Knight, T.J.; Durbin, R.D.; Langston-Unkefer, P.J.

1987-01-01

An extracellular toxin, tabtoxinine-β-lactam (TβL), is produced by Pseudomonas syringae pv. tabaci. This toxin irreversibly inhibits its target, glutamine synthetase; yet P. syringae pv. tabaci retains significant amounts of glutamine synthetase activity during toxin production in culture. As part of our investigation of the self-protection of P. syringae pv. tabaci, the authors compared the effects of TβL on Tox + (TβL-producing, insensitive to TβL) and Tox - (TβL nonproducing, sensitive to TΛ) strains. The extent of protection afforded to the Tox - strain when induced to adenylylate glutamine synthetase was tested. It was concluded that an additional protection mechanism was required. A detoxification activity was found in the Tox + strain which opens the ε-lactam ring to TβL to produce the inactive, open-chain form, tabtoxinine. Whole cells of the Tox + strain incubated for 24 h with [ 14 C]TβL (0.276 μmol/3 x 10 10 cells) contained [ 14 C]tabtoxinine (0.056 μmol), and the medium contained TβL (0.226 μmol). Extracts of spheroplasts of the Tox + stain also converted TβL to tabtoxinine, whereas extracts of the Tox - strain did not alter TβL. The conversion was time dependent and stoichiometric and was destroyed by boiling for 30 min or by the addition of 5mM EDTA. Penicillin, a possible substrate and competitive inhibitor of this lactamase activity, inhibited the conversion of TΛ to tabtoxinine. Periplasmic fluid did not catalyze the conversion of TβL

Features of air masses associated with the deposition of Pseudomonas syringae and Botrytis cinerea by rain and snowfall.

Science.gov (United States)

Monteil, Caroline L; Bardin, Marc; Morris, Cindy E

2014-11-01

Clarifying the role of precipitation in microbial dissemination is essential for elucidating the processes involved in disease emergence and spread. The ecology of Pseudomonas syringae and its presence throughout the water cycle makes it an excellent model to address this issue. In this study, 90 samples of freshly fallen rain and snow collected from 2005-2011 in France were analyzed for microbiological composition. The conditions favorable for dissemination of P. syringae by this precipitation were investigated by (i) estimating the physical properties and backward trajectories of the air masses associated with each precipitation event and by (ii) characterizing precipitation chemistry, and genetic and phenotypic structures of populations. A parallel study with the fungus Botrytis cinerea was also performed for comparison. Results showed that (i) the relationship of P. syringae to precipitation as a dissemination vector is not the same for snowfall and rainfall, whereas it is the same for B. cinerea and (ii) the occurrence of P. syringae in precipitation can be linked to electrical conductivity and pH of water, the trajectory of the air mass associated with the precipitation and certain physical conditions of the air mass (i.e. temperature, solar radiation exposure, distance traveled), whereas these predictions are different for B. cinerea. These results are pertinent to understanding microbial survival, emission sources and atmospheric processes and how they influence microbial dissemination.

Clarification of Taxonomic Status within the Pseudomonas syringae Species Group Based on a Phylogenomic Analysis

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Margarita Gomila

2017-12-01

Full Text Available The Pseudomonas syringae phylogenetic group comprises 15 recognized bacterial species and more than 60 pathovars. The classification and identification of strains is relevant for practical reasons but also for understanding the epidemiology and ecology of this group of plant pathogenic bacteria. Genome-based taxonomic analyses have been introduced recently to clarify the taxonomy of the whole genus. A set of 139 draft and complete genome sequences of strains belonging to all species of the P. syringae group available in public databases were analyzed, together with the genomes of closely related species used as outgroups. Comparative genomics based on the genome sequences of the species type strains in the group allowed the delineation of phylogenomic species and demonstrated that a high proportion of strains included in the study are misclassified. Furthermore, representatives of at least 7 putative novel species were detected. It was also confirmed that P. ficuserectae, P. meliae, and P. savastanoi are later synonyms of P. amygdali and that “P. coronafaciens” should be revived as a nomenspecies.

Pseudomonas syringae pv. Tomato DC3000 Type III secretion effector polymutants reveal an interplay between hopAD1 and AvrPtoB

Science.gov (United States)

The model pathogen Pseudomonas syringae pv. tomato DC3000 suppresses the two-tiered innate immune system of plants by injecting a complex repertoire of effector proteins into host cells via the type III secretion system. The model effector AvrPtoB has multiple domains and plant protein interactors i...

Dynamic Evolution of Pathogenicity Revealed by Sequencing and Comparative Genomics of 19 Pseudomonas syringae Isolates

Science.gov (United States)

Romanchuk, Artur; Chang, Jeff H.; Mukhtar, M. Shahid; Cherkis, Karen; Roach, Jeff; Grant, Sarah R.; Jones, Corbin D.; Dangl, Jeffery L.

2011-01-01

Closely related pathogens may differ dramatically in host range, but the molecular, genetic, and evolutionary basis for these differences remains unclear. In many Gram- negative bacteria, including the phytopathogen Pseudomonas syringae, type III effectors (TTEs) are essential for pathogenicity, instrumental in structuring host range, and exhibit wide diversity between strains. To capture the dynamic nature of virulence gene repertoires across P. syringae, we screened 11 diverse strains for novel TTE families and coupled this nearly saturating screen with the sequencing and assembly of 14 phylogenetically diverse isolates from a broad collection of diseased host plants. TTE repertoires vary dramatically in size and content across all P. syringae clades; surprisingly few TTEs are conserved and present in all strains. Those that are likely provide basal requirements for pathogenicity. We demonstrate that functional divergence within one conserved locus, hopM1, leads to dramatic differences in pathogenicity, and we demonstrate that phylogenetics-informed mutagenesis can be used to identify functionally critical residues of TTEs. The dynamism of the TTE repertoire is mirrored by diversity in pathways affecting the synthesis of secreted phytotoxins, highlighting the likely role of both types of virulence factors in determination of host range. We used these 14 draft genome sequences, plus five additional genome sequences previously reported, to identify the core genome for P. syringae and we compared this core to that of two closely related non-pathogenic pseudomonad species. These data revealed the recent acquisition of a 1 Mb megaplasmid by a sub-clade of cucumber pathogens. This megaplasmid encodes a type IV secretion system and a diverse set of unknown proteins, which dramatically increases both the genomic content of these strains and the pan-genome of the species. PMID:21799664

Pseudomonas syringae pv. phaseolicola isolated from weeds in bean crop fields.

Science.gov (United States)

Fernández-Sanz, A M; Rodicio, M R; González, A J

2016-04-01

Pseudomonas syringae pv. phaseolicola, the causative agent of halo blight in common bean (Phaseolus vulgaris L.), was isolated from weeds associated with bean crops in Spain. The bacterium was recovered from Fumaria sp, Mercurialis annua, Solanum nigrum and Sonchus oleraceus. Ps. s. pv. phaseolicola had previously been isolated from leguminous plants and S. nigrum, but to our knowledge, this is the first time it was recovered from the other three species. The isolates were phenotypically and genetically characterized, and they were compared with isolates recovered from common beans. Five different genotypic profiles were detected by PmeI-PFGE, two of them being of new description. Weed isolates were as pathogenic on bean plants as bean isolates, but they were not pathogenic on S. nigrum. Regarding the survival of the pathogen in weeds, Ps. s. pv. phaseolicola was isolated from So. oleraceus 11 weeks after the end of the bean crop. These results strongly support the idea of weeds as a potential source of inoculum for halo blight in bean. It has traditionally been considered that the main source of inoculum of Pseudomonas syringae pv. phaseolicola causing halo blight disease in Phaseolus vulgaris are the bean seeds, and that the host range of the bacterium is almost restricted to leguminous plants. In this study, the bacterium was recovered from four nonleguminous weed species collected in bean fields, and its permanence in weeds for at least 11 weeks after the harvesting of the beans was demonstrated. We have also proved that the strains isolated from weeds were pathogenic on bean plants. Accordingly, the host range of Ps. s. pv. phaseolicola could be broader than previously thought and weeds appear to be acting as a reservoir of the pathogen until the next crop. © 2016 The Society for Applied Microbiology.

Disruption of the ammonium transporter AMT1.1 alters basal defences generating resistance against Pseudomonas syringae and Plectosphaerella cucumerina

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Victoria ePastor

2014-05-01

Full Text Available Disruption of the high-affinity nitrate transporter NRT2.1 activates the priming defence against Pseudomonas syringae, resulting in enhanced resistance. In this study, it is demonstrated that the high-affinity ammonium transporter AMT1.1 is a negative regulator of Arabidopsis defence responses. The T-DNA knockout mutant amt1.1 displays enhanced resistance against Plectosphaerella cucumerina and reduced susceptibility to P. syringae. The impairment of AMT1.1 induces significant metabolic changes in the absence of challenge, suggesting that amt1.1 retains constitutive defence responses. Interestingly, amt1.1 combats pathogens differently depending on the lifestyle of the pathogen. In addition, N starvation enhances the susceptibility of wild type plants and the mutant amt1.1 to P. syringae whereas it has no effect on P. cucumerina resistance. The metabolic changes of amt1.1 against P. syringae are subtler and are restricted to the phenylpropanoid pathway, which correlates with its reduced susceptibility. By contrast, the amt1.1 mutant responds by activating higher levels of camalexin and callose against P. cucumerina. In addition, amt1.1 shows altered levels of aliphatic and indolic glucosinolates and other Trp-related compounds following infection by the necrotroph. These observations indicate that AMT1.1 may play additional roles that affect N uptake and plant immune responses.

Resistant and susceptible responses in alfalfa (Medicago sativa to bacterial stem blight caused by Pseudomonas syringae pv. syringae.

Directory of Open Access Journals (Sweden)

Lev G Nemchinov

Full Text Available Bacterial stem blight caused by Pseudomonas syringae pv. syringae is a common disease of alfalfa (Medicago sativa L. Little is known about host-pathogen interactions and host defense mechanisms. Here, individual resistant and susceptible plants were selected from cultivars Maverick and ZG9830 and used for transcript profiling at 24 and 72 hours after inoculation (hai with the isolate PssALF3. Bioinformatic analysis revealed a number of differentially expressed genes (DEGs in resistant and susceptible genotypes. Although resistant plants from each cultivar produced a hypersensitive response, transcriptome analyses indicated that they respond differently at the molecular level. The number of DEGs was higher in resistant plants of ZG9830 at 24 hai than in Maverick, suggesting that ZG9830 plants had a more rapid effector triggered immune response. Unique up-regulated genes in resistant ZG9830 plants included genes encoding putative nematode resistance HSPRO2-like proteins, orthologs for the rice Xa21 and soybean Rpg1-b resistance genes, and TIR-containing R genes lacking both NBS and LRR domains. The suite of R genes up-regulated in resistant Maverick plants had an over-representation of R genes in the CC-NBS-LRR family including two genes for atypical CCR domains and a putative ortholog of the Arabidopsis RPM1 gene. Resistance in both cultivars appears to be mediated primarily by WRKY family transcription factors and expression of genes involved in protein phosphorylation, regulation of transcription, defense response including synthesis of isoflavonoids, and oxidation-reduction processes. These results will further the identification of mechanisms involved in resistance to facilitate selection of parent populations and development of commercial varieties.

Fungicidal activities and mechanisms of action of Pseudomonas syringae pv. syringae lipodepsipeptide syringopeptins 22A and 25A

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Mekki F. Bensaci

2011-10-01

Full Text Available The plant-associated bacterium Pseudomonas syringae pv. syringae simultaneously produces two classes of metabolites: the small cyclic lipodepsinonapeptides such as the syringomycins and the larger cyclic lipodepsipeptide syringopeptins SP22 or SP25. The syringomycins inhibit a broad spectrum of fungi (but particularly yeasts by lipid-dependent membrane interaction. The syringopeptins are phytotoxic and inhibitory to Gram positive bacteria. In this study, the fungicidal activities of two major syringopeptins, SP22A and SP25A, and their mechanisms of action were investigated and compared to those of syringomycin E. SP22A and SP25A were observed to inhibit the fungal yeasts Saccharomyces cerevisiae and Candida albicans although less effectively than syringomycin E. S. cerevisiae mutants defective in ergosterol and sphingolipid biosyntheses were less susceptible to SP22A and SP25A but the relative inhibitory capabilities of SRE vs. SP22A and SP25A were maintained. Similar differences were observed for capabilities to cause cellular K+ and Ca2+ fluxes in S. cerevisiae. Interestingly, in phospholipid bilayers the syringopeptins are found to induce larger macroscopic ionic conductances than syringomycin E but form single channels with similar properties. These findings suggest that the syringopeptins target the yeast plasma membrane, and, like syringomycin E, employ a lipid-dependent channel forming mechanism of action. The differing degrees of growth inhibition by these lipodepsipeptides may be explained by differences in their hydrophobicity. The more hydrophobic SP22A and SP25A might interact more strongly with the yeast cell wall that would create a selective barrier for their incorporation into the plasma membrane.

Apoplastic peroxidases are required for salicylic acid-mediated defense against Pseudomonas syringae.

Science.gov (United States)

Mammarella, Nicole D; Cheng, Zhenyu; Fu, Zheng Qing; Daudi, Arsalan; Bolwell, G Paul; Dong, Xinnian; Ausubel, Frederick M

2015-04-01

Reactive oxygen species (ROS) generated by NADPH oxidases or apoplastic peroxidases play an important role in the plant defense response. Diminished expression of at least two Arabidopsis thaliana peroxidase encoding genes, PRX33 (At3g49110) and PRX34 (At3g49120), as a consequence of anti-sense expression of a heterologous French bean peroxidase gene (asFBP1.1), were previously shown to result in reduced levels of ROS following pathogen attack, enhanced susceptibility to a variety of bacterial and fungal pathogens, and reduced levels of callose production and defense-related gene expression in response to the microbe associated molecular pattern (MAMP) molecules flg22 and elf26. These data demonstrated that the peroxidase-dependent oxidative burst plays an important role in the elicitation of pattern-triggered immunity (PTI). Further work reported in this paper, however, shows that asFBP1.1 antisense plants are not impaired in all PTI-associated responses. For example, some but not all flg22-elicited genes are induced to lower levels by flg22 in asFPB1.1, and callose deposition in asFPB1.1 is similar to wild-type following infiltration with a Pseudomonas syringae hrcC mutant or with non-host P. syringae pathovars. Moreover, asFPB1.1 plants did not exhibit any apparent defect in their ability to mount a hypersensitive response (HR). On the other hand, salicylic acid (SA)-mediated activation of PR1 was dramatically impaired in asFPB1.1 plants. In addition, P. syringae-elicited expression of many genes known to be SA-dependent was significantly reduced in asFBP1.1 plants. Consistent with this latter result, in asFBP1.1 plants the key regulator of SA-mediated responses, NPR1, showed both dramatically decreased total protein abundance and a failure to monomerize, which is required for its translocation into the nucleus. Copyright © 2014 Elsevier Ltd. All rights reserved.

Variation in extragenic repetitive DNA sequences in Pseudomonas syringae and potential use of modified REP primers in the identification of closely related isolates

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Elif Çepni

2012-01-01

Full Text Available In this study, Pseudomonas syringe pathovars isolated from olive, tomato and bean were identified by species-specific PCR and their genetic diversity was assessed by repetitive extragenic palindromic (REP-PCR. Reverse universal primers for REP-PCR were designed by using the bases of A, T, G or C at the positions of 1, 4 and 11 to identify additional polymorphism in the banding patterns. Binding of the primers to different annealing sites in the genome revealed additional fingerprint patterns in eight isolates of P. savastanoi pv. savastanoi and two isolates of P. syringae pv. tomato. The use of four different bases in the primer sequences did not affect the PCR reproducibility and was very efficient in revealing intra-pathovar diversity, particularly in P. savastanoi pv. savastanoi. At the pathovar level, the primer BOX1AR yielded shared fragments, in addition to five bands that discriminated among the pathovars P. syringae pv. phaseolicola, P. savastanoi pv. savastanoi and P. syringae pv. tomato. REP-PCR with a modified primer containing C produced identical bands among the isolates in a pathovar but separated three pathovars more distinctly than four other primers. Although REP-and BOX-PCRs have been successfully used in the molecular identification of Pseudomonas isolates from Turkish flora, a PCR based on inter-enterobacterial repetitive intergenic concensus (ERIC sequences failed to produce clear banding patterns in this study.

Characterization of siderophore produced by Pseudomonas syringae BAF.1 and its inhibitory effects on spore germination and mycelium morphology of Fusarium oxysporum.

Science.gov (United States)

Yu, Sumei; Teng, Chunying; Liang, Jinsong; Song, Tao; Dong, Liying; Bai, Xin; Jin, Yu; Qu, Juanjuan

2017-11-01

In this study, an antagonistic bacterium against Fusarium oxysporum was identified and designated as Pseudomonas syringae strain BAF.1 on the basis of 16S rDNA sequence analysis and physiological-biochemical characteristics. It produced catechol-species siderophore at a molecular weight of 488.59 Da and a maximum amount of 55.27 μg/ml with glucose as a carbon source and asparagine as a nitrogen source at a C/N ratio of 10:1, 30°C and pH 7. The siderophore exhibited prominent antagonistic activity against Fusarium oxysporum with a maximum inhibition rate of 95.24% and had also suppressive effects on other kinds of 11 phytopathogenic fungi in the absence of FeCl 3 ·6H 2 O. Spore germination was completely inhibited by 50 μl of the siderophorecontaining solution, and the ultrastructures of mycelia and spores were also considerably suppressed by siderophore treatment as established by electron microscopy observation. These results indicate that the siderophore produced by Pseudomonas syringae BAF.1 could be potentially used for biocontrol of pathogenic Fusarium oxysporum.

Isolation and sequence analysis of the Pseudomonas syringae pv. tomato gene encoding a 2,3-diphosphoglycerate-independent phosphoglyceromutase.

Science.gov (United States)

Morris, V L; Jackson, D P; Grattan, M; Ainsworth, T; Cuppels, D A

1995-01-01

Pseudomonas syringae pv. tomato DC3481, a Tn5-induced mutant of the tomato pathogen DC3000, cannot grow and elicit disease symptoms on tomato seedlings. It also cannot grow on minimal medium containing malate, citrate, or succinate, three of the major organic acids found in tomatoes. We report here that this mutant also cannot use, as a sole carbon and/or energy source, a wide variety of hexoses and intermediates of hexose catabolism. Uptake studies have shown that DC3481 is not deficient in transport. A 3.8-kb EcoRI fragment of DC3000 DNA, which complements the Tn5 mutation, has been cloned and sequenced. The deduced amino acid sequences of two of the three open reading frames (ORFs) present on this fragment, ORF2 and ORF3, had no significant homology with sequences in the GenBank databases. However, the 510-amino-acid sequence of ORF1, the site of the Tn5 insertion, strongly resembled the deduced amino acid sequences of the Bacillus subtilis and Zea mays genes encoding 2,3-diphosphoglycerate (DPG)-independent phosphoglyceromutase (PGM) (52% identity and 72% similarity and 37% identity and 57% similarity, respectively). PGMs not requiring the cofactor DPG are usually found in plants and algae. Enzyme assays confirmed that P. syringae PGM activity required an intact ORF1. Not only is DC3481 the first PGM-deficient pseudomonad mutant to be described, but the P. syringae pgm gene is the first gram-negative bacterial gene identified that appears to code for a DPG-independent PGM. PGM activity appears essential for the growth and pathogenicity of P. syringae pv. tomato on its host plant. PMID:7896694

Isolation and sequence analysis of the Pseudomonas syringae pv. tomato gene encoding a 2,3-diphosphoglycerate-independent phosphoglyceromutase.

Science.gov (United States)

Morris, V L; Jackson, D P; Grattan, M; Ainsworth, T; Cuppels, D A

1995-04-01

Pseudomonas syringae pv. tomato DC3481, a Tn5-induced mutant of the tomato pathogen DC3000, cannot grow and elicit disease symptoms on tomato seedlings. It also cannot grow on minimal medium containing malate, citrate, or succinate, three of the major organic acids found in tomatoes. We report here that this mutant also cannot use, as a sole carbon and/or energy source, a wide variety of hexoses and intermediates of hexose catabolism. Uptake studies have shown that DC3481 is not deficient in transport. A 3.8-kb EcoRI fragment of DC3000 DNA, which complements the Tn5 mutation, has been cloned and sequenced. The deduced amino acid sequences of two of the three open reading frames (ORFs) present on this fragment, ORF2 and ORF3, had no significant homology with sequences in the GenBank databases. However, the 510-amino-acid sequence of ORF1, the site of the Tn5 insertion, strongly resembled the deduced amino acid sequences of the Bacillus subtilis and Zea mays genes encoding 2,3-diphosphoglycerate (DPG)-independent phosphoglyceromutase (PGM) (52% identity and 72% similarity and 37% identity and 57% similarity, respectively). PGMs not requiring the cofactor DPG are usually found in plants and algae. Enzyme assays confirmed that P. syringae PGM activity required an intact ORF1. Not only is DC3481 the first PGM-deficient pseudomonad mutant to be described, but the P. syringae pgm gene is the first gram-negative bacterial gene identified that appears to code for a DPG-independent PGM. PGM activity appears essential for the growth and pathogenicity of P. syringae pv. tomato on its host plant.

The stealth episome: suppression of gene expression on the excised genomic island PPHGI-1 from Pseudomonas syringae pv. phaseolicola.

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Scott A C Godfrey

2011-03-01

Full Text Available Pseudomonas syringae pv. phaseolicola is the causative agent of halo blight in the common bean, Phaseolus vulgaris. P. syringae pv. phaseolicola race 4 strain 1302A contains the avirulence gene avrPphB (syn. hopAR1, which resides on PPHGI-1, a 106 kb genomic island. Loss of PPHGI-1 from P. syringae pv. phaseolicola 1302A following exposure to the hypersensitive resistance response (HR leads to the evolution of strains with altered virulence. Here we have used fluorescent protein reporter systems to gain insight into the mobility of PPHGI-1. Confocal imaging of dual-labelled P. syringae pv. phaseolicola 1302A strain, F532 (dsRFP in chromosome and eGFP in PPHGI-1, revealed loss of PPHGI-1::eGFP encoded fluorescence during plant infection and when grown in vitro on extracted leaf apoplastic fluids. Fluorescence-activated cell sorting (FACS of fluorescent and non-fluorescent PPHGI-1::eGFP F532 populations showed that cells lost fluorescence not only when the GI was deleted, but also when it had excised and was present as a circular episome. In addition to reduced expression of eGFP, quantitative PCR on sub-populations separated by FACS showed that transcription of other genes on PPHGI-1 (avrPphB and xerC was also greatly reduced in F532 cells harbouring the excised PPHGI-1::eGFP episome. Our results show how virulence determinants located on mobile pathogenicity islands may be hidden from detection by host surveillance systems through the suppression of gene expression in the episomal state.

Characterization of Pseudomonas pathovars isolated from rosaceous fruit trees in East Algeria.

Science.gov (United States)

Harzallah, D; Sadallah, S; Larous, L

2004-01-01

A survey of bacterial diseases due to Pseudomonas on rosaceous fruit trees was conducted. In forty two orchards located in the Constantine region ( East Algeria). Pseudomonas isolates were identified on the bases of their cultural and biochemical characteristics . A total of fifty nine phytopathogenic bacteria were isolated from diseased pome and stone fruit trees. Thirty one strains comparable to Pseudomonas syringae pv. syringae were isolated from cherry (Prunus avium L.), plum (P. domestica L.), apricot (P. armeniaca L.), almond (P. dulcis L.) and pear trees (Pirus communis L.); sixteen strains comparable to Pseudomonas syringae pv. morsprunorum were obtained from samples of cherry and plum. Twelve strains of Pseudomonas viridiflava were isolated from cherry, apricot and peach (Prunus persica L.).

Early Arabidopsis root hair growth stimulation by pathogenic strains of Pseudomonas syringae.

Science.gov (United States)

Pecenková, Tamara; Janda, Martin; Ortmannová, Jitka; Hajná, Vladimíra; Stehlíková, Zuzana; Žárský, Viktor

2017-09-01

Selected beneficial Pseudomonas spp. strains have the ability to influence root architecture in Arabidopsis thaliana by inhibiting primary root elongation and promoting lateral root and root hair formation. A crucial role for auxin in this long-term (1week), long-distance plant-microbe interaction has been demonstrated. Arabidopsis seedlings were cultivated in vitro on vertical plates and inoculated with pathogenic strains Pseudomonas syringae pv. maculicola (Psm) and P. syringae pv. tomato DC3000 (Pst), as well as Agrobacterium tumefaciens (Atu) and Escherichia coli (Eco). Root hair lengths were measured after 24 and 48h of direct exposure to each bacterial strain. Several Arabidopsis mutants with impaired responses to pathogens, impaired ethylene perception and defects in the exocyst vesicle tethering complex that is involved in secretion were also analysed. Arabidopsis seedling roots infected with Psm or Pst responded similarly to when infected with plant growth-promoting rhizobacteria; root hair growth was stimulated and primary root growth was inhibited. Other plant- and soil-adapted bacteria induced similar root hair responses. The most compromised root hair growth stimulation response was found for the knockout mutants exo70A1 and ein2. The single immune pathways dependent on salicylic acid, jasmonic acid and PAD4 are not directly involved in root hair growth stimulation; however, in the mutual cross-talk with ethylene, they indirectly modify the extent of the stimulation of root hair growth. The Flg22 peptide does not initiate root hair stimulation as intact bacteria do, but pretreatment with Flg22 prior to Psm inoculation abolished root hair growth stimulation in an FLS2 receptor kinase-dependent manner. These early response phenomena are not associated with changes in auxin levels, as monitored with the pDR5::GUS auxin reporter. Early stimulation of root hair growth is an effect of an unidentified component of living plant pathogenic bacteria. The root

Isolation and characterisation of EfeM, a periplasmic component of the putative EfeUOBM iron transporter of Pseudomonas syringae pv. syringae

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Rajasekaran, Mohan B [School of Biological Sciences Harborne Building, Whiteknights Campus, Reading, RG6 6AS (United Kingdom); Structural Biology Unit at The BioCentre, University of Reading, Harborne Building, Whiteknights Campus, Reading, RG6 6AS (United Kingdom); Mitchell, Sue A; Gibson, Trevor M [Structural Biology Unit at The BioCentre, University of Reading, Harborne Building, Whiteknights Campus, Reading, RG6 6AS (United Kingdom); Hussain, Rohanah; Siligardi, Giuliano [Circular Dichroism Group, Diamond Light Source, Chiltern, Oxfordshire,OX11 0DE (United Kingdom); Andrews, Simon C [School of Biological Sciences Harborne Building, Whiteknights Campus, Reading, RG6 6AS (United Kingdom); Watson, Kimberly A, E-mail: k.a.watson@reading.ac.uk [School of Biological Sciences Harborne Building, Whiteknights Campus, Reading, RG6 6AS (United Kingdom); Structural Biology Unit at The BioCentre, University of Reading, Harborne Building, Whiteknights Campus, Reading, RG6 6AS (United Kingdom)

2010-07-30

Research highlights: {yields} Bioinformatic analysis reveals EfeM is a metallopeptidase with conserved HXXE motif. {yields} Mass spectrometry confirms EfeM consists of 251 residues, molecular weight 27,772Da. {yields} SRCD spectroscopy shows an {alpha}-helical secondary structure. {yields} Single crystals of EfeM are orthorhombic and diffract to 1.6A resolution. {yields} Space group is P22{sub 1}2{sub 1} with cell dimensions a = 46.74, b = 95.17 and c = 152.61 A. -- Abstract: The EfeM protein is a component of the putative EfeUOBM iron-transporter of Pseudomonas syringae pathovar syringae and is thought to act as a periplasmic, ferrous-iron binding protein. It contains a signal peptide of 34 amino acid residues and a C-terminal 'Peptidase{sub M}75' domain of 251 residues. The C-terminal domain contains a highly conserved 'HXXE' motif thought to act as part of a divalent cation-binding site. In this work, the gene (efeM or 'Psyr{sub 3}370') encoding EfeM was cloned and over-expressed in Escherichia coli, and the mature protein was purified from the periplasm. Mass spectrometry confirmed the identity of the protein (M{sub W} 27,772 Da). Circular dichroism spectroscopy of EfeM indicated a mainly {alpha}-helical structure, consistent with bioinformatic predictions. Purified EfeM was crystallised by hanging-drop vapor diffusion to give needle-shaped crystals that diffracted to a resolution of 1.6 A. This is the first molecular study of a peptidase M75 domain with a presumed iron transport role.

Coronatine Facilitates Pseudomonas syringae Infection of Arabidopsis Leaves at Night

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Panchal, Shweta; Roy, Debanjana; Chitrakar, Reejana; Price, Lenore; Breitbach, Zachary S.; Armstrong, Daniel W.; Melotto, Maeli

2016-01-01

In many land plants, the stomatal pore opens during the day and closes during the night. Thus, periods of darkness could be effective in decreasing pathogen penetration into leaves through stomata, the primary sites for infection by many pathogens. Pseudomonas syringae pv. tomato (Pst) DC3000 produces coronatine (COR) and opens stomata, raising an intriguing question as to whether this is a virulence strategy to facilitate bacterial infection at night. In fact, we found that (a) biological concentration of COR is effective in opening dark-closed stomata of Arabidopsis thaliana leaves, (b) the COR defective mutant Pst DC3118 is less effective in infecting Arabidopsis in the dark than under light and this difference in infection is reduced with the wild type bacterium Pst DC3000, and (c) cma, a COR biosynthesis gene, is induced only when the bacterium is in contact with the leaf surface independent of the light conditions. These findings suggest that Pst DC3000 activates virulence factors at the pre-invasive phase of its life cycle to infect plants even when environmental conditions (such as darkness) favor stomatal immunity. This functional attribute of COR may provide epidemiological advantages for COR-producing bacteria on the leaf surface. PMID:27446113

Coronatine Facilitates Pseudomonas syringae Infection of Arabidopsis Leaves at Night.

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Panchal, Shweta; Roy, Debanjana; Chitrakar, Reejana; Price, Lenore; Breitbach, Zachary S; Armstrong, Daniel W; Melotto, Maeli

2016-01-01

In many land plants, the stomatal pore opens during the day and closes during the night. Thus, periods of darkness could be effective in decreasing pathogen penetration into leaves through stomata, the primary sites for infection by many pathogens. Pseudomonas syringae pv. tomato (Pst) DC3000 produces coronatine (COR) and opens stomata, raising an intriguing question as to whether this is a virulence strategy to facilitate bacterial infection at night. In fact, we found that (a) biological concentration of COR is effective in opening dark-closed stomata of Arabidopsis thaliana leaves, (b) the COR defective mutant Pst DC3118 is less effective in infecting Arabidopsis in the dark than under light and this difference in infection is reduced with the wild type bacterium Pst DC3000, and (c) cma, a COR biosynthesis gene, is induced only when the bacterium is in contact with the leaf surface independent of the light conditions. These findings suggest that Pst DC3000 activates virulence factors at the pre-invasive phase of its life cycle to infect plants even when environmental conditions (such as darkness) favor stomatal immunity. This functional attribute of COR may provide epidemiological advantages for COR-producing bacteria on the leaf surface.

Assessment of strains of Pseudomonas syringae pv. tomato from Tanzania for resistance to copper and streptomycin

DEFF Research Database (Denmark)

Shenge, K.C.; Wydra, K.; Mabagala, M.B.

2008-01-01

Fifty-six strains of Pseudomonas syringae pv. tomato (P.s. pv. tomato) were collected from tomato-producing areas in Tanzania and assessed for resistance to copper and antibiotics. The collection was done from three tomato-producing regions (Morogoro, Arusha and Iringa), representing three...... different ecological conditions in the country. After isolation and identification, the P. s. pv. tomato strains were grown on King's medium B (KB) amended with 20% copper sulphate (w/v). The strains were also assessed for resistance to antibiotics. Results indicated that there was widespread resistance...... strains of the pathogen were moderately resistant to copper sulphate, such that 54.0% of them were able to grow on the KB medium amended with 20% (w/v) of the copper compound....

Modular Study of the Type III Effector Repertoire in Pseudomonas syringae pv. tomato DC3000 Reveals a Matrix of Effector Interplay in Pathogenesis

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Hai-Lei Wei

2018-05-01

Full Text Available Summary: The bacterial pathogen Pseudomonas syringae pv. tomato DC3000 suppresses the two-tiered innate immune system of Nicotiana benthamiana and other plants by injecting a complex repertoire of type III secretion effector (T3E proteins. Effectorless polymutant DC3000D36E was used with a modularized system for native delivery of the 29 DC3000 T3Es singly and in pairs. Assays of the performance of this T3E library in N. benthamiana leaves revealed a matrix of T3E interplay, with six T3Es eliciting death and eight others variously suppressing the death activity of the six. The T3E library was also interrogated for effects on DC3000D36E elicitation of a reactive oxygen species burst, for growth in planta, and for T3Es that reversed these effects. Pseudomonas fluorescens and Agrobacterium tumefaciens heterologous delivery systems yielded notably different sets of death-T3Es. The DC3000D36E T3E library system highlights the importance of 13 T3Es and their interplay in interactions with N. benthamiana. : Wei et al. used a Pseudomonas syringae strain lacking all known type III effectors with a modularized library expressing the 29 active effectors in the strain’s native repertoire, individually and in pairs, to comprehensively determine effector actions and interplay in inducing and suppressing responses associated with plant pathogenesis and immunity. Keywords: effector-triggered-immunity, pattern-triggered-immunity, Hop proteins, plant immunity, mini-Tn7

Pseudomonas syringae Catalases Are Collectively Required for Plant Pathogenesis

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Guo, Ming; Block, Anna; Bryan, Crystal D.; Becker, Donald F.

2012-01-01

The bacterial pathogen Pseudomonas syringae pv. tomato DC3000 must detoxify plant-produced hydrogen peroxide (H2O2) in order to survive in its host plant. Candidate enzymes for this detoxification include the monofunctional catalases KatB and KatE and the bifunctional catalase-peroxidase KatG of DC3000. This study shows that KatG is the major housekeeping catalase of DC3000 and provides protection against menadione-generated endogenous H2O2. In contrast, KatB rapidly and substantially accumulates in response to exogenous H2O2. Furthermore, KatB and KatG have nonredundant roles in detoxifying exogenous H2O2 and are required for full virulence of DC3000 in Arabidopsis thaliana. Therefore, the nonredundant ability of KatB and KatG to detoxify plant-produced H2O2 is essential for the bacteria to survive in plants. Indeed, a DC3000 catalase triple mutant is severely compromised in its ability to grow in planta, and its growth can be partially rescued by the expression of katB, katE, or katG. Interestingly, our data demonstrate that although KatB and KatG are the major catalases involved in the virulence of DC3000, KatE can also provide some protection in planta. Thus, our results indicate that these catalases are virulence factors for DC3000 and are collectively required for pathogenesis. PMID:22797762

Virulence of Pseudomonas syringae pv. tomato DC3000 Is Influenced by the Catabolite Repression Control Protein Crc.

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Chakravarthy, Suma; Butcher, Bronwyn G; Liu, Yingyu; D'Amico, Katherine; Coster, Matthew; Filiatrault, Melanie J

2017-04-01

Pseudomonas syringae infects diverse plant species and is widely used as a model system in the study of effector function and the molecular basis of plant diseases. Although the relationship between bacterial metabolism, nutrient acquisition, and virulence has attracted increasing attention in bacterial pathology, it is largely unexplored in P. syringae. The Crc (catabolite repression control) protein is a putative RNA-binding protein that regulates carbon metabolism as well as a number of other factors in the pseudomonads. Here, we show that deletion of crc increased bacterial swarming motility and biofilm formation. The crc mutant showed reduced growth and symptoms in Arabidopsis and tomato when compared with the wild-type strain. We have evidence that the crc mutant shows delayed hypersensitive response (HR) when infiltrated into Nicotiana benthamiana and tobacco. Interestingly, the crc mutant was more susceptible to hydrogen peroxide, suggesting that, in planta, the mutant may be sensitive to reactive oxygen species generated during pathogen-associated molecular pattern-triggered immunity (PTI). Indeed, HR was further delayed when PTI-induced tissues were challenged with the crc mutant. The crc mutant did not elicit an altered PTI response in plants compared with the wild-type strain. We conclude that Crc plays an important role in growth and survival during infection.

Pseudomnas syringae – a Pathogen of Fruit Trees in Serbia

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Veljko Gavrilović

2009-01-01

Full Text Available Data about symptomatology, pathogenicity and bacteriological characteristics of Pseudomonas syringae, and PCR methods for fast and reliable detection of the pathogen are given in this paper. P. syringae has been experimentaly proved as a pathogen of pear, apple, apricot, plum cherry, and raspberry, and pathogen strains have also been isolated from necrotic peach buds. Two pathogen varieties, syringae and morsprunorum, were found in our research in Serbia, the former being dominant on fruit trees.The most reliable method for detection of this bacteria is PCR, using BOX and REP primers. This method has also revealed significant differences among the strains originating from fruit trees in Serbia. Thus, it was proved that the population of P. syringae in Serbia is heterogeneous, which is very important for future epidemiologocal studies. Control of this pathogen includes mechanical, cultural and chemical measures, but integrated approach is very important for sustainable control.

Miniature transposable sequences are frequently mobilized in the bacterial plant pathogen Pseudomonas syringae pv. phaseolicola.

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Leire Bardaji

Full Text Available Mobile genetic elements are widespread in Pseudomonas syringae, and often associate with virulence genes. Genome reannotation of the model bean pathogen P. syringae pv. phaseolicola 1448A identified seventeen types of insertion sequences and two miniature inverted-repeat transposable elements (MITEs with a biased distribution, representing 2.8% of the chromosome, 25.8% of the 132-kb virulence plasmid and 2.7% of the 52-kb plasmid. Employing an entrapment vector containing sacB, we estimated that transposition frequency oscillated between 2.6×10(-5 and 1.1×10(-6, depending on the clone, although it was stable for each clone after consecutive transfers in culture media. Transposition frequency was similar for bacteria grown in rich or minimal media, and from cells recovered from compatible and incompatible plant hosts, indicating that growth conditions do not influence transposition in strain 1448A. Most of the entrapped insertions contained a full-length IS801 element, with the remaining insertions corresponding to sequences smaller than any transposable element identified in strain 1448A, and collectively identified as miniature sequences. From these, fragments of 229, 360 and 679-nt of the right end of IS801 ended in a consensus tetranucleotide and likely resulted from one-ended transposition of IS801. An average 0.7% of the insertions analyzed consisted of IS801 carrying a fragment of variable size from gene PSPPH_0008/PSPPH_0017, showing that IS801 can mobilize DNA in vivo. Retrospective analysis of complete plasmids and genomes of P. syringae suggests, however, that most fragments of IS801 are likely the result of reorganizations rather than one-ended transpositions, and that this element might preferentially contribute to genome flexibility by generating homologous regions of recombination. A further miniature sequence previously found to affect host range specificity and virulence, designated MITEPsy1 (100-nt, represented an average 2

Miniature transposable sequences are frequently mobilized in the bacterial plant pathogen Pseudomonas syringae pv. phaseolicola.

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Bardaji, Leire; Añorga, Maite; Jackson, Robert W; Martínez-Bilbao, Alejandro; Yanguas-Casás, Natalia; Murillo, Jesús

2011-01-01

Mobile genetic elements are widespread in Pseudomonas syringae, and often associate with virulence genes. Genome reannotation of the model bean pathogen P. syringae pv. phaseolicola 1448A identified seventeen types of insertion sequences and two miniature inverted-repeat transposable elements (MITEs) with a biased distribution, representing 2.8% of the chromosome, 25.8% of the 132-kb virulence plasmid and 2.7% of the 52-kb plasmid. Employing an entrapment vector containing sacB, we estimated that transposition frequency oscillated between 2.6×10(-5) and 1.1×10(-6), depending on the clone, although it was stable for each clone after consecutive transfers in culture media. Transposition frequency was similar for bacteria grown in rich or minimal media, and from cells recovered from compatible and incompatible plant hosts, indicating that growth conditions do not influence transposition in strain 1448A. Most of the entrapped insertions contained a full-length IS801 element, with the remaining insertions corresponding to sequences smaller than any transposable element identified in strain 1448A, and collectively identified as miniature sequences. From these, fragments of 229, 360 and 679-nt of the right end of IS801 ended in a consensus tetranucleotide and likely resulted from one-ended transposition of IS801. An average 0.7% of the insertions analyzed consisted of IS801 carrying a fragment of variable size from gene PSPPH_0008/PSPPH_0017, showing that IS801 can mobilize DNA in vivo. Retrospective analysis of complete plasmids and genomes of P. syringae suggests, however, that most fragments of IS801 are likely the result of reorganizations rather than one-ended transpositions, and that this element might preferentially contribute to genome flexibility by generating homologous regions of recombination. A further miniature sequence previously found to affect host range specificity and virulence, designated MITEPsy1 (100-nt), represented an average 2.4% of the total

Redox proteomics of tomato in response to Pseudomonas syringae infection

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Balmant, Kelly Mayrink; Parker, Jennifer; Yoo, Mi-Jeong; Zhu, Ning; Dufresne, Craig; Chen, Sixue

2015-01-01

Unlike mammals with adaptive immunity, plants rely on their innate immunity based on pattern-triggered immunity (PTI) and effector-triggered immunity (ETI) for pathogen defense. Reactive oxygen species, known to play crucial roles in PTI and ETI, can perturb cellular redox homeostasis and lead to changes of redox-sensitive proteins through modification of cysteine sulfhydryl groups. Although redox regulation of protein functions has emerged as an important mechanism in several biological processes, little is known about redox proteins and how they function in PTI and ETI. In this study, cysTMT proteomics technology was used to identify similarities and differences of protein redox modifications in tomato resistant (PtoR) and susceptible (prf3) genotypes in response to Pseudomonas syringae pv tomato (Pst) infection. In addition, the results of the redox changes were compared and corrected with the protein level changes. A total of 90 potential redox-regulated proteins were identified with functions in carbohydrate and energy metabolism, biosynthesis of cysteine, sucrose and brassinosteroid, cell wall biogenesis, polysaccharide/starch biosynthesis, cuticle development, lipid metabolism, proteolysis, tricarboxylic acid cycle, protein targeting to vacuole, and oxidation–reduction. This inventory of previously unknown protein redox switches in tomato pathogen defense lays a foundation for future research toward understanding the biological significance of protein redox modifications in plant defense responses. PMID:26504582

Extensive Field Survey, Laboratory and Greenhouse Studies Reveal Complex Nature of Pseudomonas syringae-Associated Hazelnut Decline in Central Italy.

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Lamichhane, Jay Ram; Bartoli, Claudia; Varvaro, Leonardo

2016-01-01

Pseudomonas avellanae (Pav) has been reported as the causal agent of bacterial decline and bacterial canker of hazelnut in Italy and Greece, respectively. Both hazelnut diseases were reported to be similar in terms of symptoms, severity and persistence. In this study, we found that both symptomatic and asymptomatic trees in the field were colonized by Pav. Multilocus Sequence Typing (MLST) analysis showed that Pav strains isolated during this study in Italy belong to the P. syringae phylogroup 1 and they are closely related to Pav strains previously isolated in Greece from hazelnut bacterial canker. On the other hand, strains isolated in earlier studies from hazelnut decline in Italy belong to both phylogroup 1 and 2 of P. syringae. Both phylogroup 1 strains of P. syringae from Greece and Italy are different than strains isolated in this study in terms of their capacity to excrete fluorescent pigments on different media. Despite the same plant genotype and cropping practices adopted, the incidence of hazelnut decline ranged from nearly 0 to 91% across our study sites. No disease developed on plants inoculated with Pav through wounding while leaf scar inoculations produced only mild disease symptoms. Based on our results and the previously reported correlation between pedo-climatic conditions and hazelnut decline, we conclude that hazelnut decline in central Italy could be incited by a combination of predisposing (adverse pedo-climatic conditions) and contributing factors (Pav). Because this is a true decline different from "bacterial canker" described in Greece, we refer to it as hazelnut decline (HD).

Extensive Field Survey, Laboratory and Greenhouse Studies Reveal Complex Nature of Pseudomonas syringae-Associated Hazelnut Decline in Central Italy.

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Jay Ram Lamichhane

Full Text Available Pseudomonas avellanae (Pav has been reported as the causal agent of bacterial decline and bacterial canker of hazelnut in Italy and Greece, respectively. Both hazelnut diseases were reported to be similar in terms of symptoms, severity and persistence. In this study, we found that both symptomatic and asymptomatic trees in the field were colonized by Pav. Multilocus Sequence Typing (MLST analysis showed that Pav strains isolated during this study in Italy belong to the P. syringae phylogroup 1 and they are closely related to Pav strains previously isolated in Greece from hazelnut bacterial canker. On the other hand, strains isolated in earlier studies from hazelnut decline in Italy belong to both phylogroup 1 and 2 of P. syringae. Both phylogroup 1 strains of P. syringae from Greece and Italy are different than strains isolated in this study in terms of their capacity to excrete fluorescent pigments on different media. Despite the same plant genotype and cropping practices adopted, the incidence of hazelnut decline ranged from nearly 0 to 91% across our study sites. No disease developed on plants inoculated with Pav through wounding while leaf scar inoculations produced only mild disease symptoms. Based on our results and the previously reported correlation between pedo-climatic conditions and hazelnut decline, we conclude that hazelnut decline in central Italy could be incited by a combination of predisposing (adverse pedo-climatic conditions and contributing factors (Pav. Because this is a true decline different from "bacterial canker" described in Greece, we refer to it as hazelnut decline (HD.

Anatomical changes on coffee leaves infected by Pseudomonas syringae pv. garcae

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Lucas Mateus Rivero Rodrigues

2015-12-01

Full Text Available ABSTRACTAlthough poorly studied, the bacterial halo blight is an important disease in the major coffee-producing states of Brazil. External damage and anatomical changes on leaves were measured in seedlings of Coffea arabica cv. Mundo Novo, susceptible to Pseudomonas syringae pv. garcae, by using histological sections obtained at 10 and 20 days after inoculation (DAI. The changes on the epidermis were smaller than the lesions measured in the mesophyll, irrespective of the evaluated colonization period, showing that the internal damage caused by the bacterium represent twice the damage observed externally. From the inoculation site, lysis occurred on the epidermal cells and on the palisade and spongy parenchyma cells, with strong staining of their cellular contents, as well as abnormal intercellular spaces in the palisade parenchyma, hypertrophy and hyperplasia of mesophyll cells and partial destruction of chloroplasts. Additionally, this study revealed the presence of inclusion bodies in epidermal and mesophyll cells. Bacterial masses were found in the apoplast between and within mesophyll cells. Bacteria were also observed in the bundle sheath and vascular bundles and were more pronounced at 20 DAI, not only near the inoculation site but also in distant areas, suggesting displacement through the vascular system. These results can be useful to understand this plant-pathogen interaction.

Abscisic Acid-Cytokinin Antagonism Modulates Resistance Against Pseudomonas syringae in Tobacco.

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Großkinsky, Dominik K; van der Graaff, Eric; Roitsch, Thomas

2014-12-01

Phytohormones are known as essential regulators of plant defenses, with ethylene, jasmonic acid, and salicylic acid as the central immunity backbone, while other phytohormones have been demonstrated to interact with this. Only recently, a function of the classic phytohormone cytokinin in plant immunity has been described in Arabidopsis, rice, and tobacco. Although interactions of cytokinins with salicylic acid and auxin have been indicated, the complete network of cytokinin interactions with other immunity-relevant phytohormones is not yet understood. Therefore, we studied the interaction of kinetin and abscisic acid as a negative regulator of plant immunity to modulate resistance in tobacco against Pseudomonas syringae. By analyzing infection symptoms, pathogen proliferation, and accumulation of the phytoalexin scopoletin as a key mediator of kinetin-induced resistance in tobacco, antagonistic interaction of these phytohormones in plant immunity was identified. Kinetin reduced abscisic acid levels in tobacco, while increased abscisic acid levels by exogenous application or inhibition of abscisic acid catabolism by diniconazole neutralized kinetin-induced resistance. Based on these results, we conclude that reduction of abscisic acid levels by enhanced abscisic acid catabolism strongly contributes to cytokinin-mediated resistance effects. Thus, the identified cytokinin-abscisic acid antagonism is a novel regulatory mechanism in plant immunity.

Identification, Cloning, and Characterization of l-Phenylserine Dehydrogenase from Pseudomonas syringae NK-15

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Sakuko Ueshima

2010-01-01

Full Text Available The gene encoding d-phenylserine dehydrogenase from Pseudomonas syringae NK-15 was identified, and a 9,246-bp nucleotide sequence containing the gene was sequenced. Six ORFs were confirmed in the sequenced region, four of which were predicted to form an operon. A homology search of each ORF predicted that orf3 encoded l-phenylserine dehydrogenase. Hence, orf3 was cloned and overexpressed in Escherichia coli cells and recombinant ORF3 was purified to homogeneity and characterized. The purified ORF3 enzyme showed l-phenylserine dehydrogenase activity. The enzymological properties and primary structure of l-phenylserine dehydrogenase (ORF3 were quite different from those of d-phenylserine dehydrogenase previously reported. l-Phenylserine dehydrogenase catalyzed the NAD+-dependent oxidation of the β-hydroxyl group of l-β-phenylserine. l-Phenylserine and l-threo-(2-thienylserine were good substrates for l-phenylserine dehydrogenase. The genes encoding l-phenylserine dehydrogenase and d-phenylserine dehydrogenase, which is induced by phenylserine, are located in a single operon. The reaction products of both enzymatic reactions were 2-aminoacetophenone and CO2.

E-2-hexenal promotes susceptibility to Pseudomonas syringae by activating jasmonic acid pathways in Arabidopsis

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Alessandra eScala

2013-04-01

Full Text Available Green Leaf Volatiles (GLVs are C6-molecules - alcohols, aldehydes and esters - produced by plants upon herbivory or during pathogen infection. Exposure to this blend of volatiles induces defence-related responses in neighboring undamaged plants, thus assigning a role to GLVs in regulating plant defences. Here we compared Arabidopsis thaliana ecotype Ler with a hydroperoxide lyase line, hpl1, unable to synthesize GLVs, for susceptibility to Pseudomonas syringae pv. tomato (DC3000. We found that the growth of DC3000 was significantly reduced in the hpl1 mutant. This phenomenon correlated with lower jasmonic acid (JA levels and higher salicylic acid (SA levels in the hpl1 mutant. Furthermore, upon infection, the JA-responsive genes VSP2 and LEC were only slightly or not induced, respectively, in hpl1. This suggests that the reduced growth of DC3000 in hpl1 plants is due to the constraint of JA-dependent responses. Treatment of hpl1 plants with E-2-hexenal, one of the more reactive GLVs, prior to infection with DC3000, resulted in increased growth of DC3000 in hpl1, thus complementing this mutant. Interestingly, the growth of DC3000 also increased in Ler plants treated with E-2-hexenal. This stronger growth was not dependent on the JA-signaling component MYC2, but on ORA59, an integrator of JA and ethylene signaling pathways, and on the production of coronatine by DC3000. GLVs may have multiple effects on plant-pathogen interactions, in this case reducing resistance to P. syringae via JA and ORA59.

Comparative genome analysis provides insights into the evolution and adaptation of Pseudomonas syringae pv. aesculi on Aesculus hippocastanum.

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Sarah Green

Full Text Available A recently emerging bleeding canker disease, caused by Pseudomonas syringae pathovar aesculi (Pae, is threatening European horse chestnut in northwest Europe. Very little is known about the origin and biology of this new disease. We used the nucleotide sequences of seven commonly used marker genes to investigate the phylogeny of three strains isolated recently from bleeding stem cankers on European horse chestnut in Britain (E-Pae. On the basis of these sequences alone, the E-Pae strains were identical to the Pae type-strain (I-Pae, isolated from leaf spots on Indian horse chestnut in India in 1969. The phylogenetic analyses also showed that Pae belongs to a distinct clade of P. syringae pathovars adapted to woody hosts. We generated genome-wide Illumina sequence data from the three E-Pae strains and one strain of I-Pae. Comparative genomic analyses revealed pathovar-specific genomic regions in Pae potentially implicated in virulence on a tree host, including genes for the catabolism of plant-derived aromatic compounds and enterobactin synthesis. Several gene clusters displayed intra-pathovar variation, including those encoding type IV secretion, a novel fatty acid biosynthesis pathway and a sucrose uptake pathway. Rates of single nucleotide polymorphisms in the four Pae genomes indicate that the three E-Pae strains diverged from each other much more recently than they diverged from I-Pae. The very low genetic diversity among the three geographically distinct E-Pae strains suggests that they originate from a single, recent introduction into Britain, thus highlighting the serious environmental risks posed by the spread of an exotic plant pathogenic bacterium to a new geographic location. The genomic regions in Pae that are absent from other P. syringae pathovars that infect herbaceous hosts may represent candidate genetic adaptations to infection of the woody parts of the tree.

Transgenic tomato plants overexpressing tyramine N-hydroxycinnamoyltransferase exhibit elevated hydroxycinnamic acid amide levels and enhanced resistance to Pseudomonas syringae.

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Campos, Laura; Lisón, Purificación; López-Gresa, María Pilar; Rodrigo, Ismael; Zacarés, Laura; Conejero, Vicente; Bellés, José María

2014-10-01

Hydroxycinnamic acid amides (HCAA) are secondary metabolites involved in plant development and defense that have been widely reported throughout the plant kingdom. These phenolics show antioxidant, antiviral, antibacterial, and antifungal activities. Hydroxycinnamoyl-CoA:tyramine N-hydroxycinnamoyl transferase (THT) is the key enzyme in HCAA synthesis and is induced in response to pathogen infection, wounding, or elicitor treatments, preceding HCAA accumulation. We have engineered transgenic tomato plants overexpressing tomato THT. These plants displayed an enhanced THT gene expression in leaves as compared with wild type (WT) plants. Consequently, leaves of THT-overexpressing plants showed a higher constitutive accumulation of the amide coumaroyltyramine (CT). Similar results were found in flowers and fruits. Moreover, feruloyltyramine (FT) also accumulated in these tissues, being present at higher levels in transgenic plants. Accumulation of CT, FT and octopamine, and noradrenaline HCAA in response to Pseudomonas syringae pv. tomato infection was higher in transgenic plants than in the WT plants. Transgenic plants showed an enhanced resistance to the bacterial infection. In addition, this HCAA accumulation was accompanied by an increase in salicylic acid levels and pathogenesis-related gene induction. Taken together, these results suggest that HCAA may play an important role in the defense of tomato plants against P. syringae infection.

Dynamics of Membrane Potential Variation and Gene Expression Induced by Spodoptera littoralis, Myzus persicae, and Pseudomonas syringae in Arabidopsis

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Bricchi, Irene; Bertea, Cinzia M.; Occhipinti, Andrea; Paponov, Ivan A.; Maffei, Massimo E.

2012-01-01

Background Biotic stress induced by various herbivores and pathogens invokes plant responses involving different defense mechanisms. However, we do not know whether different biotic stresses share a common response or which signaling pathways are involved in responses to different biotic stresses. We investigated the common and specific responses of Arabidopsis thaliana to three biotic stress agents: Spodoptera littoralis, Myzus persicae, and the pathogen Pseudomonas syringae. Methodology/Principal Findings We used electrophysiology to determine the plasma membrane potential (Vm) and we performed a gene microarray transcriptome analysis on Arabidopsis upon either herbivory or bacterial infection. Vm depolarization was induced by insect attack; however, the response was much more rapid to S. littoralis (30 min −2 h) than to M. persicae (4–6 h). M. persicae differentially regulated almost 10-fold more genes than by S. littoralis with an opposite regulation. M. persicae modulated genes involved in flavonoid, fatty acid, hormone, drug transport and chitin metabolism. S. littoralis regulated responses to heat, transcription and ion transport. The latest Vm depolarization (16 h) was found for P. syringae. The pathogen regulated responses to salicylate, jasmonate and to microorganisms. Despite this late response, the number of genes differentially regulated by P. syringae was closer to those regulated by S. littoralis than by M. persicae. Conclusions/Significance Arabidopsis plasma membranes respond with a Vm depolarization at times depending on the nature of biotic attack which allow setting a time point for comparative genome-wide analysis. A clear relationship between Vm depolarization and gene expression was found. At Vm depolarization timing, M. persicae regulates a wider array of Arabidopsis genes with a clear and distinct regulation than S. littoralis. An almost completely opposite regulation was observed between the aphid and the pathogen, with the former

The Pseudomonas syringae type III effector HopG1 targets mitochondria, alters plant development, and suppresses plant innate immunity

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Block, Anna; Guo, Ming; Li, Guangyong; Elowsky, Christian; Clemente, Thomas E.; Alfano, James R.

2009-01-01

Summary The bacterial plant pathogen Pseudomonas syringae uses a type III protein secretion system to inject type III effectors into plant cells. Primary targets of these effectors appear to be effector-triggered immunity (ETI) and pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI). The type III effector HopG1 is a suppressor of ETI that is broadly conserved in bacterial plant pathogens. Here we show that HopG1 from P. syringae pv. tomato DC3000 also suppresses PTI. Interestingly, HopG1 localizes to plant mitochondria, suggesting that its suppression of innate immunity may be linked to a perturbation of mitochondrial function. While HopG1 possesses no obvious mitochondrial signal peptide, its N-terminal two-thirds was sufficient for mitochondrial localization. A HopG1-GFP fusion lacking HopG1’s N-terminal 13 amino acids was not localized to the mitochondria reflecting the importance of the N-terminus for targeting. Constitutive expression of HopG1 in Arabidopsis thaliana, Nicotiana tabacum (tobacco) and Lycopersicon esculentum (tomato) dramatically alters plant development resulting in dwarfism, increased branching and infertility. Constitutive expression of HopG1 in planta leads to reduced respiration rates and an increased basal level of reactive oxygen species. These findings suggest that HopG1’s target is mitochondrial and that effector/target interaction promotes disease by disrupting mitochondrial functions. PMID:19863557

Hexanoic acid is a resistance inducer that protects tomato plants against Pseudomonas syringae by priming the jasmonic acid and salicylic acid pathways.

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Scalschi, Loredana; Vicedo, Begonya; Camañes, Gemma; Fernandez-Crespo, Emma; Lapeña, Leonor; González-Bosch, Carmen; García-Agustín, Pilar

2013-05-01

Hexanoic acid-induced resistance (Hx-IR) is effective against several pathogens in tomato plants. Our study of the mechanisms implicated in Hx-IR against Pseudomonas syringae pv. tomato DC3000 suggests that hexanoic acid (Hx) treatment counteracts the negative effect of coronatine (COR) and jasmonyl-isoleucine (JA-Ile) on the salicylic acid (SA) pathway. In Hx-treated plants, an increase in the expression of jasmonic acid carboxyl methyltransferase (JMT) and the SA marker genes PR1 and PR5 indicates a boost in this signalling pathway at the expense of a decrease in JA-Ile. Moreover, Hx treatment potentiates 12-oxo-phytodienoic acid accumulation, which suggests that this molecule might play a role per se in Hx-IR. These results support a positive relationship between the SA and JA pathways in Hx-primed plants. Furthermore, one of the mechanisms of virulence mediated by COR is stomatal re-opening on infection with P. syringae. In this work, we observed that Hx seems to inhibit stomatal opening in planta in the presence of COR, which suggests that, on infection in tomato, this treatment suppresses effector action to prevent bacterial entry into the mesophyll. © 2012 BSPP AND BLACKWELL PUBLISHING LTD.

The presence of INA proteins on the surface of single cells of Pseudomonas syringae R10.79 isolated from rain

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Šantl-Temkiv, Tina; Ling, Meilee; Holm, Stine; Finster, Kai; Boesen, Thomas

2016-04-01

One of the important open questions in atmospheric ice nucleation is the impact of bioaerosols on the ice content of mix phase clouds (DeMott and Prenni 2010). Biogenic ice nuclei have a unique capacity of facilitating ice formation at temperatures between -1 and -10 °C. The model biogenic ice nuclei are produced by a few species of plant-surface bacteria, such as Pseudomonas syringae, that are commonly transported through the atmosphere. These bacterial species have highly specialized proteins, the so-called ice nucleation active (INA) proteins, which are exposed at the outer membrane surface of the cell where they promote ice particle formation. The mechanisms behind the onset of INA protein synthesis in single bacterial cells are not well understood. We performed a laboratory study in order to (i) investigate the presence of INA proteins on single bacterial cells and (ii) understand the conditions that induce INA protein production. We previously isolated an INA-positive strain of Pseudomonas syringae from rain samples collected in Denmark. Bacterial cells initiated ice nucleation activity at temperatures ≤-2°C and the cell fragments at temperatures ≤-8°C (Šantl-Temkiv et al 2015). We determined the amino-acid sequence of the INA protein and used the sequence to produce custom-made antibodies (GenScript, Germany). These antibodies were used to specifically stain and visualize the INA protein on the surfaces of single cells, which can then be quantified by a technique called flow cytometry. The synthesis of INA proteins by individual cells was followed during a batch growth experiment. An unusually high proportion of cells that were adapting to the new conditions prior to growth produced INA proteins (~4.4% of all cells). A smaller fraction of actively growing cells was carrying INA proteins (~1.2 % of all cells). The cells that stopped growing due to unfavorable conditions had the lowest fraction of cells carrying INA proteins (~0.5 % of all cells). To

Constitutive Activity of the Arabidopsis MAP Kinase 3 Confers Resistance to Pseudomonas syringae and Drives Robust Immune Responses

KAUST Repository

Lang, Julien

2017-08-02

Mitogen Activated Protein Kinases (MAPKs) are known to be important mediators of plant responses to biotic and abiotic stresses. In a recent report, we enlarged the understanding of the Arabidopsis thaliana MPK3 functions showing that the expression of a constitutively active (CA) form of the protein led to auto-immune phenotypes. CA-MPK3 plants are dwarf and display defense responses that are characterized by the accumulation of salicylic acid and phytoalexins as well as by the upregulation of several defense genes. Consistently with these data, we present here results demonstrating that, compared to wild type controls, CA-MPK3 plants are more resistant to the hemibiotrophic pathogen Pseudomonas syringae DC3000. Based on our previous work, we also discuss the mechanisms of robust plant immunity controlled by sustained MPK3 activity, focusing especially on the roles of disease resistance proteins.

Constitutive activation of jasmonate signaling in an Arabidopsis mutant correlates with enhanced resistance to Erysiphe cichoracearum, Pseudomonas syringae, and Myzus persicae.

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Ellis, Christine; Karafyllidis, Ioannis; Turner, John G

2002-10-01

In Arabidopsis spp., the jasmonate (JA) response pathway generally is required for defenses against necrotrophic pathogens and chewing insects, while the salicylic acid (SA) response pathway is generally required for specific, resistance (R) gene-mediated defenses against both biotrophic and necrotrophic pathogens. For example, SA-dependent defenses are required for resistance to the biotrophic fungal pathogen Erysiphe cichoracearum UCSC1 and the bacterial pathogen Pseudomonas syringae pv. maculicola, and also are expressed during response to the green peach aphid Myzus persicae. However, recent evidence indicates that the expression of JA-dependent defenses also may confer resistance to E. cichoracearum. To confirm and to extend this observation, we have compared the disease and pest resistance of wild-type Arabidopsis plants with that of the mutants coil, which is insensitive to JA, and cev1, which has constitutive JA signaling. Measurements of the colonization of these plants by E. cichoracearum, P. syringae pv. maculicola, and M. persicae indicated that activation of the JA signal pathway enhanced resistance, and was associated with the activation of JA-dependent defense genes and the suppression of SA-dependent defense genes. We conclude that JA and SA induce alternative defense pathways that can confer resistance to the same pathogens and pests.

Controlled ice nucleation using freeze-dried Pseudomonas syringae encapsulated in alginate beads.

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Weng, Lindong; Tessier, Shannon N; Swei, Anisa; Stott, Shannon L; Toner, Mehmet

2017-04-01

The control of ice nucleation is of fundamental significance in many process technologies related to food and pharmaceutical science and cryobiology. Mechanical perturbation, electromagnetic fields and ice-nucleating agents (INAs) have been known to induce ice nucleation in a controlled manner. But these ice-nucleating methods may suffer from cumbersome manual operations, safety concerns of external fields, and biocompatibility and recovery issues of INA particles, especially when used in living systems. Given the automatic ice-seeding nature of INAs, a promising solution to overcome some of the above limitations is to engineer a biocomposite that accommodates the INA particles but minimizes their interactions with biologics, as well as enabling the recovery of used particles. In this study, freeze-dried Pseudomonas syringae, a model ice-nucleating agent, was encapsulated into microliter-sized alginate beads. We evaluated the performance of the bacterial hydrogel beads to initiate ice nucleation in water and aqueous glycerol solution by investigating factors including the size and number of the beads and the local concentration of INA particles. In the aqueous sample of a fixed volume, the total mass of the INA particles (m) was found to be the governing parameter that is solely responsible for determining the ice nucleation performance of the bacterial hydrogel beads. The freezing temperature has a strong positive linear correlation with log 10 m. The findings in this study provide an effective, predictable approach to control ice nucleation, which can improve the outcome and standardization of many ice-assisted process technologies. Copyright © 2017 Elsevier Inc. All rights reserved.

NADPH-dependent thioredoxin reductase C plays a role in nonhost disease resistance against Pseudomonas syringae pathogens by regulating chloroplast-generated reactive oxygen species

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Yasuhiro Ishiga

2016-04-01

Full Text Available Chloroplasts are cytoplasmic organelles for photosynthesis in eukaryotic cells. In addition, recent studies have shown that chloroplasts have a critical role in plant innate immunity against invading pathogens. Hydrogen peroxide is a toxic by-product from photosynthesis, which also functions as a signaling compound in plant innate immunity. Therefore, it is important to regulate the level of hydrogen peroxide in response to pathogens. Chloroplasts maintain components of the redox detoxification system including enzymes such as 2-Cys peroxiredoxins (2-Cys Prxs, and NADPH-dependent thioredoxin reductase C (NTRC. However, the significance of 2-Cys Prxs and NTRC in the molecular basis of nonhost disease resistance is largely unknown. We evaluated the roles of Prxs and NTRC using knock-out mutants of Arabidopsis in response to nonhost Pseudomonas syringae pathogens. Plants lacking functional NTRC showed localized cell death (LCD accompanied by the elevated accumulation of hydrogen peroxide in response to nonhost pathogens. Interestingly, the Arabidopsis ntrc mutant showed enhanced bacterial growth and disease susceptibility of nonhost pathogens. Furthermore, the expression profiles of the salicylic acid (SA and jasmonic acid (JA-mediated signaling pathways and phytohormone analyses including SA and JA revealed that the Arabidopsis ntrc mutant shows elevated JA-mediated signaling pathways in response to nonhost pathogen. These results suggest the critical role of NTRC in plant innate immunity against nonhost P. syringae pathogens.

Transcriptional Dynamics Driving MAMP-Triggered Immunity and Pathogen Effector-Mediated Immunosuppression in Arabidopsis Leaves Following Infection with Pseudomonas syringae pv tomato DC3000.

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Lewis, Laura A; Polanski, Krzysztof; de Torres-Zabala, Marta; Jayaraman, Siddharth; Bowden, Laura; Moore, Jonathan; Penfold, Christopher A; Jenkins, Dafyd J; Hill, Claire; Baxter, Laura; Kulasekaran, Satish; Truman, William; Littlejohn, George; Prusinska, Justyna; Mead, Andrew; Steinbrenner, Jens; Hickman, Richard; Rand, David; Wild, David L; Ott, Sascha; Buchanan-Wollaston, Vicky; Smirnoff, Nick; Beynon, Jim; Denby, Katherine; Grant, Murray

2015-11-01

Transcriptional reprogramming is integral to effective plant defense. Pathogen effectors act transcriptionally and posttranscriptionally to suppress defense responses. A major challenge to understanding disease and defense responses is discriminating between transcriptional reprogramming associated with microbial-associated molecular pattern (MAMP)-triggered immunity (MTI) and that orchestrated by effectors. A high-resolution time course of genome-wide expression changes following challenge with Pseudomonas syringae pv tomato DC3000 and the nonpathogenic mutant strain DC3000hrpA- allowed us to establish causal links between the activities of pathogen effectors and suppression of MTI and infer with high confidence a range of processes specifically targeted by effectors. Analysis of this information-rich data set with a range of computational tools provided insights into the earliest transcriptional events triggered by effector delivery, regulatory mechanisms recruited, and biological processes targeted. We show that the majority of genes contributing to disease or defense are induced within 6 h postinfection, significantly before pathogen multiplication. Suppression of chloroplast-associated genes is a rapid MAMP-triggered defense response, and suppression of genes involved in chromatin assembly and induction of ubiquitin-related genes coincide with pathogen-induced abscisic acid accumulation. Specific combinations of promoter motifs are engaged in fine-tuning the MTI response and active transcriptional suppression at specific promoter configurations by P. syringae. © 2015 American Society of Plant Biologists. All rights reserved.

Modular Study of the Type III Effector Repertoire in Pseudomonas syringae pv. tomato DC3000 Reveals a Matrix of Effector Interplay in Pathogenesis.

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Wei, Hai-Lei; Zhang, Wei; Collmer, Alan

2018-05-08

The bacterial pathogen Pseudomonas syringae pv. tomato DC3000 suppresses the two-tiered innate immune system of Nicotiana benthamiana and other plants by injecting a complex repertoire of type III secretion effector (T3E) proteins. Effectorless polymutant DC3000D36E was used with a modularized system for native delivery of the 29 DC3000 T3Es singly and in pairs. Assays of the performance of this T3E library in N. benthamiana leaves revealed a matrix of T3E interplay, with six T3Es eliciting death and eight others variously suppressing the death activity of the six. The T3E library was also interrogated for effects on DC3000D36E elicitation of a reactive oxygen species burst, for growth in planta, and for T3Es that reversed these effects. Pseudomonas fluorescens and Agrobacterium tumefaciens heterologous delivery systems yielded notably different sets of death-T3Es. The DC3000D36E T3E library system highlights the importance of 13 T3Es and their interplay in interactions with N. benthamiana. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Pseudomonas predators: understanding and exploiting phage-host interactions.

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De Smet, Jeroen; Hendrix, Hanne; Blasdel, Bob G; Danis-Wlodarczyk, Katarzyna; Lavigne, Rob

2017-09-01

Species in the genus Pseudomonas thrive in a diverse set of ecological niches and include crucial pathogens, such as the human pathogen Pseudomonas aeruginosa and the plant pathogen Pseudomonas syringae. The bacteriophages that infect Pseudomonas spp. mirror the widespread and diverse nature of their hosts. Therefore, Pseudomonas spp. and their phages are an ideal system to study the molecular mechanisms that govern virus-host interactions. Furthermore, phages are principal catalysts of host evolution and diversity, which directly affects the ecological roles of environmental and pathogenic Pseudomonas spp. Understanding these interactions not only provides novel insights into phage biology but also advances the development of phage therapy, phage-derived antimicrobial strategies and innovative biotechnological tools that may be derived from phage-bacteria interactions.

Virulence determinants of Pseudomonas syringae strains isolated from grasses in the context of a small type III effector repertoire

DEFF Research Database (Denmark)

Dudnik, Alexey; Dudler, Robert

2014-01-01

derivative that inhibits the eukaryotic proteasome. In strains colonizing dicotyledonous plants, the compound was demonstrated to suppress the salicylic-acid-dependent defense pathway. Here, we analyze virulence factors of three strains colonizing wheat (Triticum aestivum): P. syringae pathovar syringae (Psy...

Phospholipid analysis and fractional reconstitution of the ice nucleation protein activity purified from Escherichia coli overexpressing the inaZ gene of Pseudomonas syringae.

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Palaiomylitou, M A; Kalimanis, A; Koukkou, A I; Drainas, C; Anastassopoulos, E; Panopoulos, N J; Ekateriniadou, L V; Kyriakidis, D A

1998-08-01

Ice nucleation protein was partially purified from the membrane fraction of E. coli carrying inaZ from Pseudomonas syringae. The ice nucleation protein was totally localized in the bacterial envelope and was extracted by either salt (0.25 M NH4Cl) or the nonionic detergent Tween 20. The extracted protein was partially purified by sequential passage through DEAE-52 cellulose and Sephacryl-S400 columns. The activity of the purified protein was lost after treatment with phospholipase C, and its activity was subsequently restored by addition of the naturally occurring lipid phosphatidylethanolamine. These results suggest that ice nucleation proteins have a requirement for lipids that reconstitute a physiological hydrophobic environment similar to the one existing in vivo, to attain and maintain a structure that enables ice catalysis. Copyright 1998 Academic Press.

Light Regulation of Swarming Motility in Pseudomonas syringae Integrates Signaling Pathways Mediated by a Bacteriophytochrome and a LOV Protein

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Wu, Liang; McGrane, Regina S.; Beattie, Gwyn A.

2013-01-01

ABSTRACT The biological and regulatory roles of photosensory proteins are poorly understood for nonphotosynthetic bacteria. The foliar bacterial pathogen Pseudomonas syringae has three photosensory protein-encoding genes that are predicted to encode the blue-light-sensing LOV (light, oxygen, or voltage) histidine kinase (LOV-HK) and two red/far-red-light-sensing bacteriophytochromes, BphP1 and BphP2. We provide evidence that LOV-HK and BphP1 form an integrated network that regulates swarming motility in response to multiple light wavelengths. The swarming motility of P. syringae B728a deletion mutants indicated that LOV-HK positively regulates swarming motility in response to blue light and BphP1 negatively regulates swarming motility in response to red and far-red light. BphP2 does not detectably regulate swarming motility. The histidine kinase activity of each LOV-HK and BphP1 is required for this regulation based on the loss of complementation upon mutation of residues key to their kinase activity. Surprisingly, mutants lacking both lov and bphP1 were similar in motility to a bphP1 single mutant in blue light, indicating that the loss of bphP1 is epistatic to the loss of lov and also that BphP1 unexpectedly responds to blue light. Moreover, whereas expression of bphP1 did not alter motility under blue light in a bphP1 mutant, it reduced motility in a mutant lacking lov and bphP1, demonstrating that LOV-HK positively regulates motility by suppressing negative regulation by BphP1. These results are the first to show cross talk between the LOV protein and phytochrome signaling pathways in bacteria, and the similarity of this regulatory network to that of photoreceptors in plants suggests a possible common ancestry. PMID:23760465

Differential secretome analysis of Pseudomonas syringae pv tomato using gel-free MS proteomics

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Jörg eSchumacher

2014-07-01

Full Text Available The plant pathogen Pseudomonas syringae pv. tomato (DC3000 causes virulence by delivering effector proteins into host plant cells through its type three secretion system (T3SS. In response to the plant environment DC3000 expresses hypersensitive response and pathogenicity genes (hrp. Pathogenesis depends on the ability of the pathogen to manipulate the plant metabolism and to inhibit plant immunity, which depends to a large degree on the plant’s capacity to recognise both pathogen and microbial determinants (PAMP/MAMP-triggered immunity. We have developed and employed MS-based shotgun and targeted proteomics to (i elucidate the extracellular and secretome composition of DC3000 and (ii evaluate temporal features of the assembly of the T3SS and the secretion process together with its dependence of pH. The proteomic screen, under hrp inducing in vitro conditions, of extracellular and cytoplasmatic fractions indicated the segregated presence of not only T3SS implicated proteins such as HopK1, HrpK1, HrpA1 and Avrpto1, but also of proteins not usually associated with the T3SS or with pathogenicity. Using multiple reaction monitoring MS (MRM-MS to quantify HrpA1 and Avrpto1, we found that HrpA1 is rapidly expressed, at a strict pH-dependent rate and is post-translationally processed extracellularly. These features appear to not interfere with rapid Avrpto1 expression and secretion but may suggest some temporal post-translational regulatory mechanism of the T3SS assembly. The high specificity and sensitivity of the MRM-MS approach should provide a powerful tool to measure secretion and translocation in infected tissues.

Phenotypic and Genotypic Evaluation of Pseudomonas syringae pv. syringae Strains, Causing Citrus Blast in the West of Mazandaran and the East of Guilan

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S. Sameie-Shirkadeh

2017-01-01

Full Text Available Introduction: P. syringae pv. syringae (P.s.s, the causal agent of blast of citrus trees, is one of the most important plant pathogens in the world. P.s.s is unique among most P. syringae pathovars according to its ability to cause disease in over 180 species of plants in several unrelated genera. Traditionally, Strains of P.s.s are identified on the basis of biochemical and nutritional tests and symptom expression in host plants. Genomic fingerprinting methods based on the polymerase chain reaction (PCR have been applied for identification and classification of plant-associated bacteria to the subspecies level. The objectives of this study were the phenotypic and molecular evaluation of P.s. pv. syringae strains causing citrus blast in the West of Mazandaran and the East of Guilan, and study of genetic diversity of P.s.s isolates of citrus by using ERIC and REP-PCR markers. Materials and Methods: During 2011 to 2012, citrus infected tissues were sampled from different orchards in the West of Mazandaran and the East of Guilan. Bacterial phenotypes were studied based on standard physiological and biochemical tests. Gram reaction was determined by potassium hydroxide solubility test (KOH test. Strains were grown on King'B medium (KB and fluorescent pigment production was evaluated. Levan formation, oxidase reaction, potato soft rot, Arginine dihydrolase and induction of the hypersensitive reaction in tobacco leaves (LOPAT tests, were done as described by Schadd et al. The standard strains of P.s. pv. syringae form IVIA were used as reference strains in this study. Pathogenicity Test was done as described by Yessad et al. Citrus seedlings were maintained in a greenhouse at 20°C. In addition, a PCR-based method was used to confirm the genus and species of bacteria by using bacterial specific primer pair’s designed for a specific gene of syringomycin B. Genetic diversity among the strains, was studied by rep-PCR fingerprinting. Genomic

Association and Expression of Virulence from Plasmids of the Group B Strain in Pseudomonas syringae pv. eriobotryae

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Tran Dang Khanh

2018-04-01

Full Text Available Pseudomonas syringae pv. eriobotryae causes serious stem canker in loquat (Eriobotrya japonica trees. This study was conducted to determine whether plasmids are involved with its virulence. The strain NAE89, which belonged to the B group, harbored two plasmids at approximately 6.2 and 50 Mdal that caused stem canker and halo leaf spots on loquat plants. Following digestion with BamHI and ligation into the BamHI cloning site of the broad range host cosmid pLAFR3, four DNA fragments at 3.8, 6.6, 12.3, and 22.8 kb were generated. Although the plasmid-encoded virulence gene psvA was undigested with the BamHI, the halo leaf spot gene may be adjacent to the psvA gene was digested. A pLAFR3 cosmid clone was introduced into the non-pathogenic PE0 and NAE89-1 strains by triparental matings and the pathogenicity was recovered. As a result, the pLAFR3 cosmid clone was introduced into the largest size DNA fragment of 22.8 kb and determined to be the causal agent of canker on the stem of the loquat. This study revealed that the psvA gene, previously found in the 50 Mdal plasmid, was also observed in the 22.8 kb DNA fragment.

Dissection of Resistance Genes to Pseudomonas syringae pv. phaseolicola in UI3 Common Bean Cultivar.

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González, Ana M; Godoy, Luís; Santalla, Marta

2017-11-23

Few quantitative trait loci have been mapped for resistance to Pseudomonas syringae pv. phaseolicola in common bean. Two F₂ populations were developed from the host differential UI3 cultivar. The objective of this study was to further characterize the resistance to races 1, 5, 7 and 9 of Psp included in UI3. Using a QTL mapping approach, 16 and 11 main-effect QTLs for pod and primary leaf resistance were located on LG10, explaining up to 90% and 26% of the phenotypic variation, respectively. The homologous genomic region corresponding to primary leaf resistance QTLs detected tested positive for the presence of resistance-associated gene cluster encoding nucleotide-binding and leucine-rich repeat (NL), Natural Resistance Associated Macrophage (NRAMP) and Pentatricopeptide Repeat family (PPR) proteins. It is worth noting that the main effect QTLs for resistance in pod were located inside a 3.5 Mb genomic region that included the Phvul.010G021200 gene, which encodes a protein that has the highest sequence similarity to the RIN4 gene of Arabidopsis, and can be considered an important candidate gene for the organ-specific QTLs identified here. These results support that resistance to Psp from UI3 might result from the immune response activated by combinations of R proteins, and suggest the guard model as an important mechanism in pod resistance to halo blight. The candidate genes identified here warrant functional studies that will help in characterizing the actual defense gene(s) in UI3 genotype.

Defence responses of arabidopsis thaliana to infection by pseudomonas syringae are regulated by the circadian clock

KAUST Repository

Bhardwaj, Vaibhav

2011-10-31

The circadian clock allows plants to anticipate predictable daily changes in abiotic stimuli, such as light; however, whether the clock similarly allows plants to anticipate interactions with other organisms is unknown. Here we show that Arabidopsis thaliana (Arabidopsis) has circadian clock-mediated variation in resistance to the virulent bacterial pathogen Pseudomonas syringae pv. tomato DC3000 (Pst DC3000), with plants being least susceptible to infection in the subjective morning. We suggest that the increased resistance to Pst DC3000 observed in the morning in Col-0 plants results from clock-mediated modulation of pathogen associated molecular pattern (PAMP)-triggered immunity. Analysis of publicly available microarray data revealed that a large number of Arabidopsis defence-related genes showed both diurnal- and circadian-regulation, including genes involved in the perception of the PAMP flagellin which exhibit a peak in expression in the morning. Accordingly, we observed that PAMP-triggered callose deposition was significantly higher in wild-type plants inoculated with Pst DC3000 hrpA in the subjective morning than in the evening, while no such temporal difference was evident in arrhythmic plants. Our results suggest that PAMP-triggered immune responses are modulated by the circadian clock and that temporal regulation allows plants to anticipate and respond more effectively to pathogen challenges in the daytime. © 2011 Bhardwaj et al.

The Ca2+ induced two-component system, CvsSR regulates the Type III secretion system and the extracytoplasmic function sigma-factor AlgU in Pseudomonas syringae pv. tomato DC3000.

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Fishman, Maxwell R; Zhang, Johnson; Bronstein, Philip A; Stodghill, Paul; Filiatrault, Melanie J

2017-12-20

Two-component systems (TCSs) of bacteria regulate many different aspects of the bacterial life cycle including pathogenesis. Most TCSs remain uncharacterized with no information about the signal(s) or regulatory targets and/or role in bacterial pathogenesis. Here, we characterized a TCS in the plant-pathogenic bacterium Pseudomonas syringae pv. tomato DC3000 ( Pto ) composed of the histidine kinase, CvsS, and the response regulator, CvsR. CvsSR is necessary for virulence of Pto , since ΔcvsS and ΔcvsR strains produced fewer symptoms and demonstrated reduced growth on multiple hosts as compared to WT. We discovered that expression of cvsSR is induced by Ca 2+ concentrations found in leaf apoplastic fluid. Thus, Ca 2+ can be added to the list of signals that promote pathogenesis of Pto during host colonization. Through chromatin immunoprecipitation followed by next generation sequencing (ChIP-seq) and global transcriptome analysis (RNA-seq) we discerned the CvsR regulon. CvsR directly activated expression of the type III secretion system regulators, hrpR and hrpS , that regulates Pto virulence in a type III secretion system dependent manner. CvsR also indirectly repressed transcription of the extracytoplasmic sigma factor algU and production of alginate. Phenotypic analysis determined that CvsSR inversely regulated biofilm formation, swarming motility, and cellulose production in a Ca 2+ -dependent manner. Overall, our results show that CvsSR is a key regulatory hub critical for interaction with host plants. Importance Pathogenic bacteria must be able to react and respond to the surrounding environment, make use of available resources, and avert or counter host immune responses. Often, these abilities rely on two-component systems (TCSs) composed of interacting proteins that modulate gene expression. We identified a TCS in the plant-pathogenic bacterium Pseudomonas syringae that responds to the presence of calcium, which is an important signal during the plant

Comparison of the complete genome sequences of Pseudomonassyringae pv. syringae B728a and pv. tomato DC3000.

Energy Technology Data Exchange (ETDEWEB)

Feil, Helene; Feil, William S.; Chain, Patrick; Larimer, Frank; DiBartolo, Genevieve; Copeland, Alex; Lykidis, Athanasios; Trong,Stephen; Nolan, Matt; Goltsman, Eugene; Thiel, James; Malfatti,Stephanie; Loper, Joyce E.; Lapidus, Alla; Detter, John C.; Land, Miriam; Richardson, Paul M.; Kyrpides, Nikos C.; Ivanova, Natalia; Lindow, StevenE.

2005-04-01

The complete genomic sequence of Pseudomonas syringaepathovar syringae B728a (Pss B728a), has been determined and is comparedwith that of Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). Thesetwo pathovars of this economically important species of plant pathogenicbacteria differ in host range and apparent patterns of interaction withplants, with Pss having a more pronounced epiphytic stage of growth andhigher abiotic stress tolerance and Pst DC3000 having a more pronouncedapoplastic growth habitat. The Pss B728a genome (6.1 megabases) containsa circular chromosome and no plasmid, whereas the Pst DC3000 genome is6.5 mbp in size, composed of a circular chromosome and two plasmids.While a high degree of similarity exists between the two sequencedPseudomonads, 976 protein-encoding genes are unique to Pss B728a whencompared to Pst DC3000, including large genomic islands likely tocontribute to virulence and host specificity. Over 375 repetitiveextragenic palindromic sequences (REPs) unique to Pss B728a when comparedto Pst DC3000 are widely distributed throughout the chromosome except in14 genomic islands, which generally had lower GC content than the genomeas a whole. Content of the genomic islands vary, with one containing aprophage and another the plasmid pKLC102 of P. aeruginosa PAO1. Among the976 genes of Pss B728a with no counterpart in Pst DC3000 are thoseencoding for syringopeptin (SP), syringomycin (SR), indole acetic acidbiosynthesis, arginine degradation, and production of ice nuclei. Thegenomic comparison suggests that several unique genes for Pss B728a suchas ectoine synthase, DNA repair, and antibiotic production may contributeto epiphytic fitness and stress tolerance of this organism. Pseudomonassyringae, a member of the gamma subgroup of the Proteobacteria, is awidespread bacterial pathogen of many plant species. The species P.syringae is subdivided into approximately 50 pathovars based onpathogenicity and host range. P. syringae is capable of

Response of tobacco to the Pseudomonas syringae pv. Tomato DC3000 is mainly dependent on salicylic acid signaling pathway.

Science.gov (United States)

Liu, Yang; Wang, Li; Cai, Guohua; Jiang, Shanshan; Sun, Liping; Li, Dequan

2013-07-01

Pseudomonas syringae pv. Tomato DC3000 (Pst DC3000) was the first pathogen to be demonstrated to infect Arabidopsis and to cause disease symptoms in the laboratory setting. However, the defense response to Pst DC3000 was unclear in tobacco. In this report, the expression profiles of twelve defense response-related genes were analyzed after treatment with salicylic acid (SA), jasmonic acid (JA), and pathogen Pst DC3000 by qRT-PCR. According to our results, it could be presented that the genes primarily induced by SA were also induced to higher levels after Pst DC3000 infection. SA accumulation could be induced to a higher level than that of JA after Pst DC3000 infection. In addition, SA could result in hypersensitive response (HR), which did not completely depend on accumulation of reactive oxygen species. These results indicated that tobacco mainly depended on SA signaling pathway rather than on JA signaling pathway in response to Pst DC3000. Further study demonstrated that JA could significantly inhibit the accumulation of SA and the generation of the HR induced by Pst DC3000. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Multilayered Regulation of Ethylene Induction Plays a Positive Role in Arabidopsis Resistance against Pseudomonas syringae.

Science.gov (United States)

Guan, Rongxia; Su, Jianbin; Meng, Xiangzong; Li, Sen; Liu, Yidong; Xu, Juan; Zhang, Shuqun

2015-09-01

Ethylene, a key phytohormone involved in plant-pathogen interaction, plays a positive role in plant resistance against fungal pathogens. However, its function in plant bacterial resistance remains unclear. Here, we report a detailed analysis of ethylene induction in Arabidopsis (Arabidopsis thaliana) in response to Pseudomonas syringae pv tomato DC3000 (Pst). Ethylene biosynthesis is highly induced in both pathogen/microbe-associated molecular pattern (PAMP)-triggered immunity and effector-triggered immunity (ETI), and the induction is potentiated by salicylic acid (SA) pretreatment. In addition, Pst actively suppresses PAMP-triggered ethylene induction in a type III secretion system-dependent manner. SA potentiation of ethylene induction is dependent mostly on MITOGEN-ACTIVATED PROTEIN KINASE6 (MPK6) and MPK3 and their downstream ACS2 and ACS6, two type I isoforms of 1-aminocyclopropane-1-carboxylic acid synthases (ACSs). ACS7, a type III ACS whose expression is enhanced by SA pretreatment, is also involved. Pst expressing the avrRpt2 effector gene (Pst-avrRpt2), which is capable of triggering ETI, induces a higher level of ethylene production, and the elevated portion is dependent on SALICYLIC ACID INDUCTION DEFICIENT2 and NONEXPRESSER OF PATHOGENESIS-RELATED GENE1, two key players in SA biosynthesis and signaling. High-order ACS mutants with reduced ethylene induction are more susceptible to both Pst and Pst-avrRpt2, demonstrating a positive role of ethylene in plant bacterial resistance mediated by both PAMP-triggered immunity and ETI. © 2015 American Society of Plant Biologists. All Rights Reserved.

Dissection of Resistance Genes to Pseudomonas syringae pv. phaseolicola in UI3 Common Bean Cultivar

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Ana M. González

2017-11-01

Full Text Available Few quantitative trait loci have been mapped for resistance to Pseudomonas syringae pv. phaseolicola in common bean. Two F2 populations were developed from the host differential UI3 cultivar. The objective of this study was to further characterize the resistance to races 1, 5, 7 and 9 of Psp included in UI3. Using a QTL mapping approach, 16 and 11 main-effect QTLs for pod and primary leaf resistance were located on LG10, explaining up to 90% and 26% of the phenotypic variation, respectively. The homologous genomic region corresponding to primary leaf resistance QTLs detected tested positive for the presence of resistance-associated gene cluster encoding nucleotide-binding and leucine-rich repeat (NL, Natural Resistance Associated Macrophage (NRAMP and Pentatricopeptide Repeat family (PPR proteins. It is worth noting that the main effect QTLs for resistance in pod were located inside a 3.5 Mb genomic region that included the Phvul.010G021200 gene, which encodes a protein that has the highest sequence similarity to the RIN4 gene of Arabidopsis, and can be considered an important candidate gene for the organ-specific QTLs identified here. These results support that resistance to Psp from UI3 might result from the immune response activated by combinations of R proteins, and suggest the guard model as an important mechanism in pod resistance to halo blight. The candidate genes identified here warrant functional studies that will help in characterizing the actual defense gene(s in UI3 genotype.

Overexpression of SAMDC1 gene in Arabidopsis thaliana increases expression of defense-related genes as well as resistance to Pseudomonas syringae and Hyaloperonospora arabidopsidis

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Francisco eMarco

2014-03-01

Full Text Available It has been previously described that elevation of endogenous spermine levels in Arabidopsis could be achieved by transgenic overexpression of S-Adenosylmethionine decarboxylase (SAMDC or Spermine synthase (SPMS. In both cases, spermine accumulation had an impact on the plant transcriptome, with up-regulation of a set of genes enriched in functional categories involved in defense-related processes against both biotic and abiotic stresses. In this work, the response of SAMDC1-overexpressing plants against bacterial and oomycete pathogens has been tested. The expression of several pathogen defense-related genes was induced in these plants as well as in wild type plants exposed to an exogenous supply of spermine. SAMDC1-overexpressing plants showed an increased tolerance to infection by Pseudomonas syringae and by Hyaloperonospora arabidopsidis. Both results add more evidence to the hypothesis that spermine plays a key role in plant resistance to biotic stress.

Diversity of small RNAs expressed in Pseudomonas species

DEFF Research Database (Denmark)

Gomez-Lozano, Mara; Marvig, Rasmus Lykke; Molina-Santiago, Carlos

2015-01-01

RNA sequencing (RNA-seq) has revealed several hundreds of previously undetected small RNAs (sRNAs) in all bacterial species investigated, including strains of Pseudomonas aeruginosa, Pseudomonas putida and Pseudomonas syringae. Nonetheless, only little is known about the extent of conservation...... of expressed sRNAs across strains and species. In this study, we have used RNA-seq to identify sRNAs in P.putidaDOT-T1E and Pseudomonas extremaustralis 14-3b. This is the first strain of P.extremaustralis and the second strain of P.putida to have their transcriptomes analysed for sRNAs, and we identify...... the presence of around 150 novel sRNAs in each strain. Furthermore, we provide a comparison based on sequence conservation of all the sRNAs detected by RNA-seq in the Pseudomonas species investigated so far. Our results show that the extent of sRNA conservation across different species is very limited...

Plant innate immunity induced by flagellin suppresses the hypersensitive response in non-host plants elicited by Pseudomonas syringae pv. averrhoi.

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Chia-Fong Wei

Full Text Available A new pathogen, Pseudomonas syringae pv. averrhoi (Pav, which causes bacterial spot disease on carambola was identified in Taiwan in 1997. Many strains of this pathovar have been isolated from different locations and several varieties of hosts. Some of these strains, such as HL1, are nonmotile and elicit a strong hypersensitive response (HR in nonhost tobacco leaves, while other strains, such as PA5, are motile and elicit a weak HR. Based on the image from a transmission electron microscope, the results showed that HL1 is flagellum-deficient and PA5 has normal flagella. Here we cloned and analyzed the fliC gene and glycosylation island from Pav HL1 and PA5. The amino acid sequences of FliC from HL1 and PA5 are identical to P. s. pvs. tabaci (Pta, glycinea and phaseolicola and share very high similarity with other pathovars of P. syringae. In contrast to the flagellin mutant PtaΔfliC, PA5ΔfliC grows as well as wild type in the host plant, but it elicits stronger HR than wild type does in non-host plants. Furthermore, the purified Pav flagellin, but not the divergent flagellin from Agrobacterium tumefaciens, is able to impair the HR induced by PA5ΔfliC. PA5Δfgt1 possessing nonglycosylated flagella behaved as its wild type in both bacterial growth in host and HR elicitation. Flagellin was infiltrated into tobacco leaves either simultaneously with flagellum-deficient HL1 or prior to the inoculation of wild type HL1, and both treatments impaired the HR induced by HL1. Moreover, the HR elicited by PA5 and PA5ΔfliC was enhanced by the addition of cycloheximide, suggesting that the flagellin is one of the PAMPs (pathogen-associated molecular patterns contributed to induce the PAMP-triggered immunity (PTI. Taken together, the results shown in this study reveal that flagellin in Pav is capable of suppressing HR via PTI induction during an incompatible interaction.

Plant Innate Immunity Induced by Flagellin Suppresses the Hypersensitive Response in Non-Host Plants Elicited by Pseudomonas syringae pv. averrhoi

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Wei, Chia-Fong; Hsu, Shih-Tien; Deng, Wen-Ling; Wen, Yu-Der; Huang, Hsiou-Chen

2012-01-01

A new pathogen, Pseudomonas syringae pv. averrhoi (Pav), which causes bacterial spot disease on carambola was identified in Taiwan in 1997. Many strains of this pathovar have been isolated from different locations and several varieties of hosts. Some of these strains, such as HL1, are nonmotile and elicit a strong hypersensitive response (HR) in nonhost tobacco leaves, while other strains, such as PA5, are motile and elicit a weak HR. Based on the image from a transmission electron microscope, the results showed that HL1 is flagellum-deficient and PA5 has normal flagella. Here we cloned and analyzed the fliC gene and glycosylation island from Pav HL1 and PA5. The amino acid sequences of FliC from HL1 and PA5 are identical to P. s. pvs. tabaci (Pta), glycinea and phaseolicola and share very high similarity with other pathovars of P. syringae. In contrast to the flagellin mutant PtaΔfliC, PA5ΔfliC grows as well as wild type in the host plant, but it elicits stronger HR than wild type does in non-host plants. Furthermore, the purified Pav flagellin, but not the divergent flagellin from Agrobacterium tumefaciens, is able to impair the HR induced by PA5ΔfliC. PA5Δfgt1 possessing nonglycosylated flagella behaved as its wild type in both bacterial growth in host and HR elicitation. Flagellin was infiltrated into tobacco leaves either simultaneously with flagellum-deficient HL1 or prior to the inoculation of wild type HL1, and both treatments impaired the HR induced by HL1. Moreover, the HR elicited by PA5 and PA5ΔfliC was enhanced by the addition of cycloheximide, suggesting that the flagellin is one of the PAMPs (pathogen-associated molecular patterns) contributed to induce the PAMP-triggered immunity (PTI). Taken together, the results shown in this study reveal that flagellin in Pav is capable of suppressing HR via PTI induction during an incompatible interaction. PMID:22911741

Pseudomonas syringae evades host immunity by degrading flagellin monomers with alkaline protease AprA.

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Pel, Michiel J C; van Dijken, Anja J H; Bardoel, Bart W; Seidl, Michael F; van der Ent, Sjoerd; van Strijp, Jos A G; Pieterse, Corné M J

2014-07-01

Bacterial flagellin molecules are strong inducers of innate immune responses in both mammals and plants. The opportunistic pathogen Pseudomonas aeruginosa secretes an alkaline protease called AprA that degrades flagellin monomers. Here, we show that AprA is widespread among a wide variety of bacterial species. In addition, we investigated the role of AprA in virulence of the bacterial plant pathogen P. syringae pv. tomato DC3000. The AprA-deficient DC3000 ΔaprA knockout mutant was significantly less virulent on both tomato and Arabidopsis thaliana. Moreover, infiltration of A. thaliana Col-0 leaves with DC3000 ΔaprA evoked a significantly higher level of expression of the defense-related genes FRK1 and PR-1 than did wild-type DC3000. In the flagellin receptor mutant fls2, pathogen virulence and defense-related gene activation did not differ between DC3000 and DC3000 ΔaprA. Together, these results suggest that AprA of DC3000 is important for evasion of recognition by the FLS2 receptor, allowing wild-type DC3000 to be more virulent on its host plant than AprA-deficient DC3000 ΔaprA. To provide further evidence for the role of DC3000 AprA in host immune evasion, we overexpressed the AprA inhibitory peptide AprI of DC3000 in A. thaliana to counteract the immune evasive capacity of DC3000 AprA. Ectopic expression of aprI in A. thaliana resulted in an enhanced level of resistance against wild-type DC3000, while the already elevated level of resistance against DC3000 ΔaprA remained unchanged. Together, these results indicate that evasion of host immunity by the alkaline protease AprA is important for full virulence of strain DC3000 and likely acts by preventing flagellin monomers from being recognized by its cognate immune receptor.

NH4+ protects tomato plants against Pseudomonas syringae by activation of systemic acquired acclimation.

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Fernández-Crespo, Emma; Scalschi, Loredana; Llorens, Eugenio; García-Agustín, Pilar; Camañes, Gemma

2015-11-01

NH4 (+) nutrition provokes mild toxicity by enhancing H2O2 accumulation, which acts as a signal activating systemic acquired acclimation (SAA). Until now, induced resistance mechanisms in response to an abiotic stimulus and related to SAA were only reported for exposure to a subsequent abiotic stress. Herein, the first evidence is provided that this acclimation to an abiotic stimulus induces resistance to later pathogen infection, since NH4 (+) nutrition (N-NH4 (+))-induced resistance (NH4 (+)-IR) against Pseudomonas syringae pv tomato DC3000 (Pst) in tomato plants was demonstrated. N-NH4 (+) plants displayed basal H2O2, abscisic acid (ABA), and putrescine (Put) accumulation. H2O2 accumulation acted as a signal to induce ABA-dependent signalling pathways required to prevent NH4 (+) toxicity. This acclimatory event provoked an increase in resistance against later pathogen infection. N-NH4 (+) plants displayed basal stomatal closure produced by H2O2 derived from enhanced CuAO and rboh1 activity that may reduce the entry of bacteria into the mesophyll, diminishing the disease symptoms as well as strongly inducing the oxidative burst upon Pst infection, favouring NH4 (+)-IR. Experiments with inhibitors of Put accumulation and the ABA-deficient mutant flacca demonstrated that Put and ABA downstream signalling pathways are required to complete NH4 (+)-IR. The metabolic profile revealed that infected N-NH4 (+) plants showed greater ferulic acid accumulation compared with control plants. Although classical salicylic acid (SA)-dependent responses against biotrophic pathogens were not found, the important role of Put in the resistance of tomato against Pst was demonstrated. Moreover, this work revealed the cross-talk between abiotic stress acclimation (NH4 (+) nutrition) and resistance to subsequent Pst infection. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Multilayered Regulation of Ethylene Induction Plays a Positive Role in Arabidopsis Resistance against Pseudomonas syringae1[OPEN

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Guan, Rongxia; Su, Jianbin; Meng, Xiangzong; Li, Sen; Liu, Yidong; Xu, Juan; Zhang, Shuqun

2015-01-01

Ethylene, a key phytohormone involved in plant-pathogen interaction, plays a positive role in plant resistance against fungal pathogens. However, its function in plant bacterial resistance remains unclear. Here, we report a detailed analysis of ethylene induction in Arabidopsis (Arabidopsis thaliana) in response to Pseudomonas syringae pv tomato DC3000 (Pst). Ethylene biosynthesis is highly induced in both pathogen/microbe-associated molecular pattern (PAMP)-triggered immunity and effector-triggered immunity (ETI), and the induction is potentiated by salicylic acid (SA) pretreatment. In addition, Pst actively suppresses PAMP-triggered ethylene induction in a type III secretion system-dependent manner. SA potentiation of ethylene induction is dependent mostly on MITOGEN-ACTIVATED PROTEIN KINASE6 (MPK6) and MPK3 and their downstream ACS2 and ACS6, two type I isoforms of 1-aminocyclopropane-1-carboxylic acid synthases (ACSs). ACS7, a type III ACS whose expression is enhanced by SA pretreatment, is also involved. Pst expressing the avrRpt2 effector gene (Pst-avrRpt2), which is capable of triggering ETI, induces a higher level of ethylene production, and the elevated portion is dependent on SALICYLIC ACID INDUCTION DEFICIENT2 and NONEXPRESSER OF PATHOGENESIS-RELATED GENE1, two key players in SA biosynthesis and signaling. High-order ACS mutants with reduced ethylene induction are more susceptible to both Pst and Pst-avrRpt2, demonstrating a positive role of ethylene in plant bacterial resistance mediated by both PAMP-triggered immunity and ETI. PMID:26265775

Elicitation of Induced Resistance against Pectobacterium carotovorum and Pseudomonas syringae by Specific Individual Compounds Derived from Native Korean Plant Species

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Choong-Min Ryu

2013-10-01

Full Text Available Plants have developed general and specific defense mechanisms for protection against various enemies. Among the general defenses, induced resistance has distinct characteristics, such as broad-spectrum resistance and long-lasting effectiveness. This study evaluated over 500 specific chemical compounds derived from native Korean plant species to determine whether they triggered induced resistance against Pectobacterium carotovorum supsp. carotovorum (Pcc in tobacco (Nicotiana tabacum and Pseudomonas syringae pv. tomato (Pst in Arabidopsis thaliana. To select target compound(s with direct and indirect (volatile effects, a new Petri-dish-based in vitro disease assay system with four compartments was developed. The screening assay showed that capsaicin, fisetin hydrate, jaceosidin, and farnesiferol A reduced the disease severity significantly in tobacco. Of these four compounds, capsaicin and jaceosidin induced resistance against Pcc and Pst, which depended on both salicylic acid (SA and jasmonic acid (JA signaling, using Arabidopsis transgenic and mutant lines, including npr1 and NahG for SA signaling and jar1 for JA signaling. The upregulation of the PR2 and PDF1.2 genes after Pst challenge with capsaicin pre-treatment indicated that SA and JA signaling were primed. These results demonstrate that capsaicin and jaceosidin can be effective triggers of strong induced resistance against both necrotrophic and biotrophic plant pathogens.

Global transcriptional responses of Pseudomonas syringae DC3000 to changes in iron bioavailability in vitro

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Rutzke Michael

2008-12-01

Full Text Available Abstract Background Pseudomonas syringae pv tomato DC3000 (DC3000 is a Gram-negative model plant pathogen that is found in a wide variety of environments. To survive in these diverse conditions it must sense and respond to various environmental cues. One micronutrient required for most forms of life is iron. Bioavailable iron has been shown to be an important global regulator for many bacteria where it not only regulates a wide variety of genes involved in general cell physiology but also virulence determinants. In this study we used microarrays to study differential gene regulation in DC3000 in response to changes in levels of cell-associated iron. Results DC3000 cultures were grown under highly controlled conditions and analyzed after the addition of iron citrate or sodium citrate to the media. In the cultures supplemented with iron, we found that cell-associated iron increased rapidly while culture densities were not significantly different over 4 hours when compared to cultures with sodium citrate added. Microarray analysis of samples taken from before and after the addition of either sodium citrate or iron citrate identified 386 differentially regulated genes with high statistical confidence. Differentially regulated genes were clustered based on expression patterns observed between comparison of samples taken at different time points and with different supplements. This analysis grouped genes associated with the same regulatory motifs and/or had similar putative or known function. Conclusion This study shows iron is rapidly taken up from the medium by iron-depleted DC3000 cultures and that bioavailable iron is a global cue for the expression of iron transport, storage, and known virulence factors in DC3000. Furthermore approximately 34% of the differentially regulated genes are associated with one of four regulatory motifs for Fur, PvdS, HrpL, or RpoD.

JMJ27, an Arabidopsis H3K9 histone demethylase, modulates defense against Pseudomonas syringae and flowering time.

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Dutta, Aditya; Choudhary, Pratibha; Caruana, Julie; Raina, Ramesh

2017-09-01

Histone methylation is known to dynamically regulate diverse developmental and physiological processes. Histone methyl marks are written by methyltransferases and erased by demethylases, and result in modification of chromatin structure to repress or activate transcription. However, little is known about how histone methylation may regulate defense mechanisms and flowering time in plants. Here we report characterization of JmjC DOMAIN-CONTAINING PROTEIN 27 (JMJ27), an Arabidopsis JHDM2 (JmjC domain-containing histone demethylase 2) family protein, which modulates defense against pathogens and flowering time. JMJ27 is a nuclear protein containing a zinc-finger motif and a catalytic JmjC domain with conserved Fe(II) and α-ketoglutarate binding sites, and displays H3K9me1/2 demethylase activity both in vitro and in vivo. JMJ27 is induced in response to virulent Pseudomonas syringae pathogens and is required for resistance against these pathogens. JMJ27 is a negative modulator of WRKY25 (a repressor of defense) and a positive modulator of several pathogenesis-related (PR) proteins. Additionally, loss of JMJ27 function leads to early flowering. JMJ27 negatively modulates the major flowering regulator CONSTANS (CO) and positively modulates FLOWERING LOCUS C (FLC). Taken together, our results indicate that JMJ27 functions as a histone demethylase to modulate both physiological (defense) and developmental (flowering time) processes in Arabidopsis. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

The levels of nitrite and nitrate, proline and protein profiles in tomato plants infected with pseudomonas syringae

International Nuclear Information System (INIS)

Berber, I.; Onlu, H.

2012-01-01

In this study, the contents of nitrite-nitrate and free L-proline, and pathogenesis-related (PR) proteins in tomato plants following inoculation with Pseudomonas syringae pv. tomato strain were examined. The results of the nitrite and nitrate indicated that there was a reduction in the levels of nitrate in the infected tomato plants through 1-8 study days, compared with the healthy plants. On the other hands, when the nitrite amounts increased in the first and second days, the nitrite concentrations reduced in infected plants at subsequent time periods, compared with uninfected plants. The accumulation of free proline increased in the infected plants, according to control plants. The whole-cell protein profiles displayed that the levels of the protein bands of molecular masses 204.6 kDa and 69.9 kDa significantly increased in infected and uninfected plants during 2-10 study days. In additionally, in the quantities of the protein bands of molecular weights 90.3 and 79.4 kDa were observed an increase in the infected and healthy plants after the fourth day. However, the protein band of molecular weight 54.3 kDa was visible only in uninfected plants for the fourth and eighth days. Finally, the study suggest that there were the sophisticate relationships among the proline accumulation, the conversion of nitrate to nitrite and the induction of PR protein genes in the regulation of defense mechanisms toward microbial invaders. Our results also indicated that the increases in nitrite and proline contents might be useful indicator for the response toward pathogen attacks. (author)

Genomic Structural Variations Affecting Virulence During Clonal Expansion of Pseudomonas syringae pv. actinidiae Biovar 3 in Europe.

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Firrao, Giuseppe; Torelli, Emanuela; Polano, Cesare; Ferrante, Patrizia; Ferrini, Francesca; Martini, Marta; Marcelletti, Simone; Scortichini, Marco; Ermacora, Paolo

2018-01-01

Pseudomonas syringae pv. actinidiae (Psa) biovar 3 caused pandemic bacterial canker of Actinidia chinensis and Actinidia deliciosa since 2008. In Europe, the disease spread rapidly in the kiwifruit cultivation areas from a single introduction. In this study, we investigated the genomic diversity of Psa biovar 3 strains during the primary clonal expansion in Europe using single molecule real-time (SMRT), Illumina and Sanger sequencing technologies. We recorded evidences of frequent mobilization and loss of transposon Tn6212, large chromosome inversions, and ectopic integration of IS sequences (remarkably ISPsy31, ISPsy36, and ISPsy37). While no phenotype change associated with Tn6212 mobilization could be detected, strains CRAFRU 12.29 and CRAFRU 12.50 did not elicit the hypersensitivity response (HR) on tobacco and eggplant leaves and were limited in their growth in kiwifruit leaves due to insertion of ISPsy31 and ISPsy36 in the hrpS and hrpR genes, respectively, interrupting the hrp cluster. Both strains had been isolated from symptomatic plants, suggesting coexistence of variant strains with reduced virulence together with virulent strains in mixed populations. The structural differences caused by rearrangements of self-genetic elements within European and New Zealand strains were comparable in number and type to those occurring among the European strains, in contrast with the significant difference in terms of nucleotide polymorphisms. We hypothesize a relaxation, during clonal expansion, of the selection limiting the accumulation of deleterious mutations associated with genome structural variation due to transposition of mobile elements. This consideration may be relevant when evaluating strategies to be adopted for epidemics management.

The Identification of Genes Important in Pseudomonas syringae pv. phaseolicola Plant Colonisation Using In Vitro Screening of Transposon Libraries.

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Bharani Manoharan

Full Text Available The bacterial plant pathogen Pseudomonas syringae pv. phaseolicola (Pph colonises the surface of common bean plants before moving into the interior of plant tissue, via wounds and stomata. In the intercellular spaces the pathogen proliferates in the apoplastic fluid and forms microcolonies (biofilms around plant cells. If the pathogen can suppress the plant's natural resistance response, it will cause halo blight disease. The process of resistance suppression is fairly well understood, but the mechanisms used by the pathogen in colonisation are less clear. We hypothesised that we could apply in vitro genetic screens to look for changes in motility, colony formation, and adhesion, which are proxies for infection, microcolony formation and cell adhesion. We made transposon (Tn mutant libraries of Pph strains 1448A and 1302A and found 106/1920 mutants exhibited alterations in colony morphology, motility and biofilm formation. Identification of the insertion point of the Tn identified within the genome highlighted, as expected, a number of altered motility mutants bearing mutations in genes encoding various parts of the flagellum. Genes involved in nutrient biosynthesis, membrane associated proteins, and a number of conserved hypothetical protein (CHP genes were also identified. A mutation of one CHP gene caused a positive increase in in planta bacterial growth. This rapid and inexpensive screening method allows the discovery of genes important for in vitro traits that can be correlated to roles in the plant interaction.

Natural variation in partial resistance to Pseudomonas syringae is controlled by two major QTLs in Arabidopsis thaliana.

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Laure Perchepied

Full Text Available BACKGROUND: Low-level, partial resistance is pre-eminent in natural populations, however, the mechanisms underlying this form of resistance are still poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, we used the model pathosystem Pseudomonas syringae pv. tomato DC3000 (Pst - Arabidopsis thaliana to study the genetic basis of this form of resistance. Phenotypic analysis of a set of Arabidopsis accessions, based on evaluation of in planta pathogen growth revealed extensive quantitative variation for partial resistance to Pst. It allowed choosing a recombinant inbred line (RIL population derived from a cross between the accessions Bayreuth and Shahdara for quantitative genetic analysis. Experiments performed under two different environmental conditions led to the detection of two major and two minor quantitative trait loci (QTLs governing partial resistance to Pst and called PRP-Ps1 to PRP-Ps4. The two major QTLs, PRP-Ps1 and PRP-Ps2, were confirmed in near isogenic lines (NILs, following the heterogeneous inbred families (HIFs strategy. Analysis of marker gene expression using these HIFs indicated a negative correlation between the induced amount of transcripts of SA-dependent genes PR1, ICS and PR5, and the in planta bacterial growth in the HIF segregating at PRP-Ps2 locus, suggesting an implication of PRP-Ps2 in the activation of SA dependent responses. CONCLUSIONS/SIGNIFICANCE: These results show that variation in partial resistance to Pst in Arabidopsis is governed by relatively few loci, and the validation of two major loci opens the way for their fine mapping and their cloning, which will improve our understanding of the molecular mechanisms underlying partial resistance.

Pollen as a possible pathway for the dissemination of Pseudomonas syringae pv. actinide and bacterial canker of kiwifruit

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Rodanthi TONTOU

2014-09-01

Full Text Available Pollen collected in a kiwifruit orchard with symptoms of bacterial canker and naturally contaminated by Pseudomonas syringae pv. actinidiae (Psa, was used to pollinate an experimental orchard, in order to confirm its role, under commercial orchard conditions, in disseminating the pathogen and, possibly, contributing to disease spread. A pollen lot, certified free from Psa, was used with the same methods as a control. Two pollination techniques were used: dusting (dry pollen and spraying (pollen suspension in water. The orchard was monitored during 2 years from experimental pollination, with regular sampling of flowers, fruits, leaves, and vines, to check for Psa as an epiphyte or endophyte, and for bacterial canker symptoms. Psa was recovered from flowers, fruitlets and leaves during the first season, mainly in plots where contaminated pollen had been sprayed in water suspension. From early August until harvesting time (mid-October, Psa detection was possible only on leaves. No symptoms developed during the first season after pollination. No endophytic Psa was detected in pruned vines in the following winter. During the second season, detection and isolation of Psa was erratic, but direct isolation was achieved from four plots. During the second season after pollination, typical leaf symptoms were observed on a few vines, and Psa was isolated and identified. Our results suggest that Psa could be disseminated via contaminated kiwifruit pollen as a pathway for spread of bacterial canker. However, further pollination experiments are needed to establish, beyond any doubt, whether contaminated pollen may contribute to possible disease outbreaks.

A possible role for acetylated intermediates in diaminopimelate and tabtoxinine-beta-lactam biosynthesis in Pseudomonas syringae pv. tabaci BR2.024.

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Liu, L; Shaw, P D

1997-01-01

The deduced product of an open reading frame (ORF3) located in the tabtoxinine-beta-lactam (T beta L) biosynthetic region of Pseudomonas syringae pv. tabaci BR2.024 (BR2.024) has significant sequence homology to the dapD products of other bacteria. dapD encodes L-2,3,4,5-tetrahydrodipicolinate succinyl coenzyme A succinyltransferase (THDPA-ST), an enzyme in the diaminopimelate (DAP) and lysine biosynthetic pathway. Complementation studies, in vitro transcription-translation experiments, and enzymatic assays indicated that ORF3 encodes a product with THDPA-ST activity in Escherichia coli dapD mutant beta 274. However, a BR2.024 mutant with an insert in ORF3 was prototrophic, and only basal THDPA-ST activity was detected in extracts of both parent and mutant. This finding suggested that ORF3 was not required for DAP biosynthesis and that it did not encode a product with THDPA-ST activity. The results of enzymatic studies, indicating that BR2.024 uses acetylated intermediates for DAP biosynthesis, are consistent with the hypothesis that BR2.024 does not need THDPA-ST for DAP biosynthesis. The ORF3 mutant produced reduced levels of tabtoxin, indicating that ORF3 may have a role in T beta L biosynthesis. We have named the gene tabB and have proposed a possible function for the gene product. PMID:9294453

The Arabidopsis thaliana cysteine-rich receptor-like kinase CRK20 modulates host responses to Pseudomonas syringae pv. tomato DC3000 infection.

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Ederli, Luisa; Madeo, Laura; Calderini, Ornella; Gehring, Chris; Moretti, Chiaraluce; Buonaurio, Roberto; Paolocci, Francesco; Pasqualini, Stefania

2011-10-15

In plants, the cysteine-rich repeat kinases (CRKs) are a sub-family of receptor-like protein kinases that contain the DUF26 motif in their extracellular domains. It has been shown that in Arabidopsis thaliana, CRK20 is transcriptionally induced by pathogens, salicylic acid and ozone (O(3)). However, its role in responses to biotic and abiotic stress remains to be elucidated. To determine the function of CRK20 in such responses, two CRK20 loss-of-function mutants, crk20-1 and crk20-2, were isolated from public collections of Arabidopsis T-DNA tagged lines and examined for responses to O(3) and Pseudomonas syringae pv. tomato (Pst) DC3000. crk20-1 and crk20-2 showed similar O(3) sensitivities and no differences in the expression of defense genes when compared with the wild-type. However, pathogen growth was significantly reduced, while there were no differences in the induction of salicylic acid related defense genes or salicylic acid accumulation. Furthermore, correlation analysis of CRK20 gene expression suggests that it has a role in the control of H(2)O and/or nutrient transport. We therefore propose that CRK20 promotes conditions that are favorable for Pst DC3000 growth in Arabidopsis, possibly through the regulation of apoplastic homeostasis, and consequently, of the environment of this biotrophic pathogen. Copyright © 2011 Elsevier GmbH. All rights reserved.

The Arabidopsis thaliana cysteine-rich receptor-like kinase CRK20 modulates host responses to Pseudomonas syringae pv. tomato DC3000 infection

KAUST Repository

Ederli, Luisa

2011-10-01

In plants, the cysteine-rich repeat kinases (CRKs) are a sub-family of receptor-like protein kinases that contain the DUF26 motif in their extracellular domains. It has been shown that in Arabidopsis thaliana, CRK20 is transcriptionally induced by pathogens, salicylic acid and ozone (O3). However, its role in responses to biotic and abiotic stress remains to be elucidated. To determine the function of CRK20 in such responses, two CRK20 loss-of-function mutants, crk20-1 and crk20-2, were isolated from public collections of Arabidopsis T-DNA tagged lines and examined for responses to O3 and Pseudomonas syringae pv. tomato (Pst) DC3000. crk20-1 and crk20-2 showed similar O3 sensitivities and no differences in the expression of defense genes when compared with the wild-type. However, pathogen growth was significantly reduced, while there were no differences in the induction of salicylic acid related defense genes or salicylic acid accumulation. Furthermore, correlation analysis of CRK20 gene expression suggests that it has a role in the control of H2O and/or nutrient transport. We therefore propose that CRK20 promotes conditions that are favorable for Pst DC3000 growth in Arabidopsis, possibly through the regulation of apoplastic homeostasis, and consequently, of the environment of this biotrophic pathogen. © 2011 Elsevier GmbH.

Evolutionary Plasticity of AmrZ Regulation in Pseudomonas

Science.gov (United States)

Dougherty, Kevin; Diaz, Beatriz; Murillo, Rachel

2018-01-01

ABSTRACT amrZ encodes a master regulator protein conserved across pseudomonads, which can be either a positive or negative regulator of swimming motility depending on the species examined. To better understand plasticity in the regulatory function of AmrZ, we characterized the mode of regulation for this protein for two different motility-related phenotypes in Pseudomonas stutzeri. As in Pseudomonas syringae, AmrZ functions as a positive regulator of swimming motility within P. stutzeri, which suggests that the functions of this protein with regard to swimming motility have switched at least twice across pseudomonads. Shifts in mode of regulation cannot be explained by changes in AmrZ sequence alone. We further show that AmrZ acts as a positive regulator of colony spreading within this strain and that this regulation is at least partially independent of swimming motility. Closer investigation of mechanistic shifts in dual-function regulators like AmrZ could provide unique insights into how transcriptional pathways are rewired between closely related species. IMPORTANCE Microbes often display finely tuned patterns of gene regulation across different environments, with major regulatory changes controlled by a small group of “master” regulators within each cell. AmrZ is a master regulator of gene expression across pseudomonads and can be either a positive or negative regulator for a variety of pathways depending on the strain and genomic context. Here, we demonstrate that the phenotypic outcomes of regulation of swimming motility by AmrZ have switched at least twice independently in pseudomonads, so that AmrZ promotes increased swimming motility in P. stutzeri and P. syringae but represses this phenotype in Pseudomonas fluorescens and Pseudomonas aeruginosa. Since examples of switches in regulatory mode are relatively rare, further investigation into the mechanisms underlying shifts in regulator function for AmrZ could provide unique insights into the

Arabidopsis AtERF15 positively regulates immunity against Pseudomonas syringae pv. tomato DC3000 and Botrytis cinerea

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Huijuan eZhang

2015-09-01

Full Text Available Upon pathogen infection, activation of immune response requires effective transcriptional reprogramming that regulates inducible expression of a large set of defense genes. A number of ethylene-responsive factor transcription factors have been shown to play critical roles in regulating immune responses in plants. In the present study, we explored the functions of Arabidopsis AtERF15 in immune responses against Pseudomonas syringae pv. tomato (Pst DC3000, a (hemibiotrophic bacterial pathogen, and Botrytis cinerea, a necrotrophic fungal pathogen. Expression of AtERF15 was induced by infection of Pst DC3000 and B. cinerea and by treatments with salicylic acid (SA and methyl jasmonate. Biochemical assays demonstrated that AtERF15 is a nucleus-localized transcription activator. The AtERF15-overexpressing (AtERF15-OE plants displayed enhanced resistance while the AtERF15-RNAi plants exhibited decreased resistance against Pst DC3000 and B. cinerea. Meanwhile, Pst DC3000- or B. cinerea-induced expression of defense genes was upregulated in AtERF15-OE plants but downregulated in AtERF15-RNAi plants, as compared to the expression in wild type plants. In response to infection with B. cinerea, the AtERF15-OE plants accumulated less reactive oxygen species (ROS while the AtERF15-RNAi plants accumulated more ROS. The flg22- and chitin-induced oxidative burst was abolished and expression levels of the pattern-triggered immunity-responsive genes AtFRK1 and AtWRKY53 were suppressed in AtER15-RNAi plants upon treatment with flg22 or chitin. Furthermore, SA-induced defense response was also partially impaired in the AtERF15-RNAi plants. These data demonstrate that AtERF15 is a positive regulator of multiple layers of the immune responses in Arabidopsis.

Immunocytochemical localization of HrpA and HrpZ supports a role for the Hrp pilus in the transfer of effector proteins from Pseudomonas syringae pv. tomato across the host plant cell wall.

Science.gov (United States)

Brown, I R; Mansfield, J W; Taira, S; Roine, E; Romantschuk, M

2001-03-01

The Hrp pilus, composed of HrpA subunits, is an essential component of the type III secretion system in Pseudomonas syringae. We used electron microscopy (EM) and immunocytochemistry to examine production of the pilus in vitro from P. syringae pv. tomato strain DC3000 grown under hrp-inducing conditions on EM grids. Pili, when labeled with antibodies to HrpA, developed rapidly in a nonpolar manner shortly after the detection of the hrpA transcript and extended up to 5 microm into surrounding media. Structures at the base of the pilus were clearly differentiated from the basal bodies of flagella. The HrpZ protein, also secreted via the type III system, was found by immunogold labeling to be associated with the pilus in vitro. Accumulation and secretion of HrpA and HrpZ were also examined quantitatively after the inoculation of wild-type DC3000 and hrpA and hrpZ mutants into leaves of Arabidopsis thaliana. The functional pilus crossed the plant cell wall to generate tracks of immunogold labeling for HrpA and HrpZ. Mutants that produced HrpA but did not assemble pili were nonpathogenic, did not secrete HrpA protein, and were compromised for the accumulation of HrpZ. A model is proposed in which the rapidly elongating Hrp pilus acts as a moving conveyor, facilitating transfer of effector proteins from bacteria to the plant cytoplasm across the formidable barrier of the plant cell wall.

The plant pathogen Pseudomonas syringae pv. tomato is genetically monomorphic and under strong selection to evade tomato immunity.

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Rongman Cai

2011-08-01

Full Text Available Recently, genome sequencing of many isolates of genetically monomorphic bacterial human pathogens has given new insights into pathogen microevolution and phylogeography. Here, we report a genome-based micro-evolutionary study of a bacterial plant pathogen, Pseudomonas syringae pv. tomato. Only 267 mutations were identified between five sequenced isolates in 3,543,009 nt of analyzed genome sequence, which suggests a recent evolutionary origin of this pathogen. Further analysis with genome-derived markers of 89 world-wide isolates showed that several genotypes exist in North America and in Europe indicating frequent pathogen movement between these world regions. Genome-derived markers and molecular analyses of key pathogen loci important for virulence and motility both suggest ongoing adaptation to the tomato host. A mutational hotspot was found in the type III-secreted effector gene hopM1. These mutations abolish the cell death triggering activity of the full-length protein indicating strong selection for loss of function of this effector, which was previously considered a virulence factor. Two non-synonymous mutations in the flagellin-encoding gene fliC allowed identifying a new microbe associated molecular pattern (MAMP in a region distinct from the known MAMP flg22. Interestingly, the ancestral allele of this MAMP induces a stronger tomato immune response than the derived alleles. The ancestral allele has largely disappeared from today's Pto populations suggesting that flagellin-triggered immunity limits pathogen fitness even in highly virulent pathogens. An additional non-synonymous mutation was identified in flg22 in South American isolates. Therefore, MAMPs are more variable than expected differing even between otherwise almost identical isolates of the same pathogen strain.

Interlaboratorium vergelijking van het onderzoek naar Aeromonas spp. in drinkwater

NARCIS (Netherlands)

Havelaar AH; During M; Versteegh JFM

1986-01-01

Door middel van onderzoek van zes kunstmatig besmette gesimuleerde monsters drinkwater ( 4 Aeromonas spp., 1 Klebsiella oxytoca, 1 Pseudomonas aeruginosa) werd een vergelijking gemaakt van de resultaten van Aeromonas onderzoek in 14 laboratoria. De tellingen in de deelnemende laboratoria

Expression of Vitis amurensis VaERF20 in Arabidopsis thaliana Improves Resistance to Botrytis cinerea and Pseudomonas syringae pv. Tomato DC3000

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Mengnan Wang

2018-03-01

Full Text Available Ethylene response factor (ERF transcription factors play important roles in regulating immune responses in plants. In our study, we characterized a member of the ERF transcription factor family, VaERF20, from the Chinese wild Vitis genotype, V. amurensis Rupr “Shuangyou”. Phylogenetic analysis indicated that VaERF20 belongs to group IXc of the ERF family, in which many members are known to contribute to fighting pathogen infection. Consistent with this, expression of VaERF20 was induced by treatment with the necrotrophic fungal pathogen Botrytis cinerea (B. cinerea in “Shuangyou” and V. vinifera “Red Globe”. Arabidopsis thaliana plants over-expressing VaERF20 displayed enhanced resistance to B. cinerea and the bacterium Pseudomonas syringae pv. tomato (Pst DC3000. Patterns of pathogen-induced reactive oxygen species (ROS accumulation were entirely distinct in B. cinerea and PstDC3000 inoculated plants. Examples of both salicylic acid (SA and jasmonic acid/ethylene (JA/ET responsive defense genes were up-regulated after B. cinerea and PstDC3000 inoculation of the VaERF20-overexpressing transgenic A. thaliana plants. Evidence of pattern-triggered immunity (PTI, callose accumulation and stomatal defense, together with increased expression of PTI genes, was also greater in the transgenic lines. These data indicate that VaERF20 participates in various signal transduction pathways and acts as an inducer of immune responses.

Characterization of dapB, a gene required by Pseudomonas syringae pv. tabaci BR2.024 for lysine and tabtoxinine-beta-lactam biosynthesis.

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Liu, L; Shaw, P D

1997-01-01

The dapB gene, which encodes L-2,3-dihydrodipicolinate reductase, the second enzyme of the lysine branch of the aspartic amino acid family, was cloned and sequenced from a tabtoxin-producing bacterium, Pseudomonas syringae pv. tabaci BR2.024. The deduced amino acid sequence shared 60 to 90% identity to known dapB gene products from gram-negative bacteria and 19 to 21% identity to the dapB products from gram-positive bacteria. The consensus sequence for the NAD(P)H binding site [(V/I)(A/G)(V/I)XGXXGXXG)] and the proposed substrate binding site (HHRHK) were conserved in the polypeptide. A BR2.024 dapB mutant is a diaminopimelate auxotroph and tabtoxin negative. The addition of a mixture of L-,L-, D,D-, and meso-diaminopimelate to defined media restored growth but not tabtoxin production. Cloned DNA fragments containing the parental dapB gene restored the ability to grow in defined media and tabtoxin production to the dapB mutant. These results indicate that the dapB gene is required for both lysine and tabtoxin biosynthesis, thus providing the first genetic evidence that the biosynthesis of tabtoxin proceeds in part along the lysine biosynthetic pathway. These data also suggest that L-2,3,4,5-tetrahydrodipicolinate is a common intermediate for both lysine and tabtoxin biosynthesis. PMID:8990304

Modeling and mapping the current and future distribution of Pseudomonas syringae pv. actinidiae under climate change in China.

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Rulin Wang

Full Text Available Bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae (Psa is a major threat to the kiwifruit industry throughout the world and accounts for substantial economic losses in China. The aim of the present study was to test and explore the possibility of using MaxEnt (maximum entropy models to predict and analyze the future large-scale distribution of Psa in China.Based on the current environmental factors, three future climate scenarios, which were suggested by the fifth IPCC report, and the current distribution sites of Psa, MaxEnt combined with ArcGIS was applied to predict the potential suitable areas and the changing trend of Psa in China. The jackknife test and correlation analysis were used to choose dominant climatic factors. The receiver operating characteristic curve (ROC drawn by MaxEnt was used to evaluate the accuracy of the simulation.The results showed that under current climatic conditions, the area from latitude 25° to 36°N and from longitude 101° to 122°E is the primary potential suitable area of Psa in China. The highly suitable area (with suitability between 66 and 100 was mainly concentrated in Northeast Sichuan, South Shaanxi, most of Chongqing, West Hubei and Southwest Gansu and occupied 4.94% of land in China. Under different future emission scenarios, both the areas and the centers of the suitable areas all showed differences compared with the current situation. Four climatic variables, i.e., maximum April temperature (19%, mean temperature of the coldest quarter (14%, precipitation in May (11.5% and minimum temperature in October (10.8%, had the largest impact on the distribution of Psa.The MaxEnt model is potentially useful for forecasting the future adaptive distribution of Psa under climate change, and it provides important guidance for comprehensive management.

Modeling and mapping the current and future distribution of Pseudomonas syringae pv. actinidiae under climate change in China.

Science.gov (United States)

Wang, Rulin; Li, Qing; He, Shisong; Liu, Yuan; Wang, Mingtian; Jiang, Gan

2018-01-01

Bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae (Psa) is a major threat to the kiwifruit industry throughout the world and accounts for substantial economic losses in China. The aim of the present study was to test and explore the possibility of using MaxEnt (maximum entropy models) to predict and analyze the future large-scale distribution of Psa in China. Based on the current environmental factors, three future climate scenarios, which were suggested by the fifth IPCC report, and the current distribution sites of Psa, MaxEnt combined with ArcGIS was applied to predict the potential suitable areas and the changing trend of Psa in China. The jackknife test and correlation analysis were used to choose dominant climatic factors. The receiver operating characteristic curve (ROC) drawn by MaxEnt was used to evaluate the accuracy of the simulation. The results showed that under current climatic conditions, the area from latitude 25° to 36°N and from longitude 101° to 122°E is the primary potential suitable area of Psa in China. The highly suitable area (with suitability between 66 and 100) was mainly concentrated in Northeast Sichuan, South Shaanxi, most of Chongqing, West Hubei and Southwest Gansu and occupied 4.94% of land in China. Under different future emission scenarios, both the areas and the centers of the suitable areas all showed differences compared with the current situation. Four climatic variables, i.e., maximum April temperature (19%), mean temperature of the coldest quarter (14%), precipitation in May (11.5%) and minimum temperature in October (10.8%), had the largest impact on the distribution of Psa. The MaxEnt model is potentially useful for forecasting the future adaptive distribution of Psa under climate change, and it provides important guidance for comprehensive management.

A genetic screen reveals Arabidopsis stomatal and/or apoplastic defenses against Pseudomonas syringae pv. tomato DC3000.

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Weiqing Zeng

2011-10-01

Full Text Available Bacterial infection of plants often begins with colonization of the plant surface, followed by entry into the plant through wounds and natural openings (such as stomata, multiplication in the intercellular space (apoplast of the infected tissues, and dissemination of bacteria to other plants. Historically, most studies assess bacterial infection based on final outcomes of disease and/or pathogen growth using whole infected tissues; few studies have genetically distinguished the contribution of different host cell types in response to an infection. The phytotoxin coronatine (COR is produced by several pathovars of Pseudomonas syringae. COR-deficient mutants of P. s. tomato (Pst DC3000 are severely compromised in virulence, especially when inoculated onto the plant surface. We report here a genetic screen to identify Arabidopsis mutants that could rescue the virulence of COR-deficient mutant bacteria. Among the susceptible to coronatine-deficient Pst DC3000 (scord mutants were two that were defective in stomatal closure response, two that were defective in apoplast defense, and four that were defective in both stomatal and apoplast defense. Isolation of these three classes of mutants suggests that stomatal and apoplastic defenses are integrated in plants, but are genetically separable, and that COR is important for Pst DC3000 to overcome both stomatal guard cell- and apoplastic mesophyll cell-based defenses. Of the six mutants defective in bacterium-triggered stomatal closure, three are defective in salicylic acid (SA-induced stomatal closure, but exhibit normal stomatal closure in response to abscisic acid (ABA, and scord7 is compromised in both SA- and ABA-induced stomatal closure. We have cloned SCORD3, which is required for salicylic acid (SA biosynthesis, and SCORD5, which encodes an ATP-binding cassette (ABC protein, AtGCN20/AtABCF3, predicted to be involved in stress-associated protein translation control. Identification of SCORD5 begins to

Pseudomonas savastanoi pv. savastanoi: some like it knot.

Science.gov (United States)

Ramos, Cayo; Matas, Isabel M; Bardaji, Leire; Aragón, Isabel M; Murillo, Jesús

2012-12-01

Pseudomonas savastanoi pv. savastanoi is the causal agent of olive (Olea europaea) knot disease and an unorthodox member of the P. syringae complex, causing aerial tumours instead of the foliar necroses and cankers characteristic of most members of this complex. Olive knot is present wherever olive is grown; although losses are difficult to assess, it is assumed that olive knot is one of the most important diseases of the olive crop. The last century witnessed a large number of scientific articles describing the biology, epidemiology and control of this pathogen. However, most P. savastanoi pv. savastanoi strains are highly recalcitrant to genetic manipulation, which has effectively prevented the pathogen from benefitting from the scientific progress in molecular biology that has elevated the foliar pathogens of the P. syringae complex to supermodels. A number of studies in recent years have made significant advances in the biology, ecology and genetics of P. savastanoi pv. savastanoi, paving the way for the molecular dissection of its interaction with other nonpathogenic bacteria and their woody hosts. The selection of a genetically pliable model strain was soon followed by the development of rapid methods for virulence assessment with micropropagated olive plants and the analysis of cellular interactions with the plant host. The generation of a draft genome of strain NCPPB 3335 and the closed sequence of its three native plasmids has allowed for functional and comparative genomic analyses for the identification of its pathogenicity gene complement. This includes 34 putative type III effector genes and genomic regions, shared with other pathogens of woody hosts, which encode metabolic pathways associated with the degradation of lignin-derived compounds. Now, the time is right to explore the molecular basis of the P. savastanoi pv. savastanoi-olive interaction and to obtain insights into why some pathovars like it necrotic and why some like it knot

Natural variation for responsiveness to flg22, flgII-28, and csp22 and Pseudomonas syringae pv. tomato in heirloom tomatoes.

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Selvakumar Veluchamy

Full Text Available Tomato (Solanum lycopersicum L. is susceptible to many diseases including bacterial speck caused by Pseudomonas syringae pv. tomato. Bacterial speck disease is a serious problem worldwide in tomato production areas where moist conditions and cool temperatures occur. To enhance breeding of speck resistant fresh-market tomato cultivars we identified a race 0 field isolate, NC-C3, of P. s. pv. tomato in North Carolina and used it to screen a collection of heirloom tomato lines for speck resistance in the field. We observed statistically significant variation among the heirloom tomatoes for their response to P. s. pv. tomato NC-C3 with two lines showing resistance approaching a cultivar that expresses the Pto resistance gene, although none of the heirloom lines have Pto. Using an assay that measures microbe-associated molecular pattern (MAMP-induced production of reactive oxygen species (ROS, we investigated whether the heirloom lines showed differential responsiveness to three bacterial-derived peptide MAMPs: flg22 and flgII-28 (from flagellin and csp22 (from cold shock protein. Significant differences were observed for MAMP responsiveness among the lines, although these differences did not correlate strongly with resistance or susceptibility to bacterial speck disease. The identification of natural variation for MAMP responsiveness opens up the possibility of using a genetic approach to identify the underlying loci and to facilitate breeding of cultivars with enhanced disease resistance. Towards this goal, we discovered that responsiveness to csp22 segregates as a single locus in an F2 population of tomato.

The Arabidopsis lectin receptor kinase LecRK-V.5 represses stomatal immunity induced by Pseudomonas syringae pv. tomato DC3000.

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Marie Desclos-Theveniau

2012-02-01

Full Text Available Stomata play an important role in plant innate immunity by limiting pathogen entry into leaves but molecular mechanisms regulating stomatal closure upon pathogen perception are not well understood. Here we show that the Arabidopsis thaliana L-type lectin receptor kinase-V.5 (LecRK-V.5 negatively regulates stomatal immunity. Loss of LecRK-V.5 function increased resistance to surface inoculation with virulent bacteria Pseudomonas syringae pv tomato DC3000. Levels of resistance were not affected after infiltration-inoculation, suggesting that LecRK-V.5 functions at an early defense stage. By contrast, lines overexpressing LecRK-V.5 were more susceptible to Pst DC3000. Enhanced resistance in lecrk-V.5 mutants was correlated with constitutive stomatal closure, while increased susceptibility phenotypes in overexpression lines were associated with early stomatal reopening. Lines overexpressing LecRK-V.5 also demonstrated a defective stomatal closure after pathogen-associated molecular pattern (PAMP treatments. LecRK-V.5 is rapidly expressed in stomatal guard cells after bacterial inoculation or treatment with the bacterial PAMP flagellin. In addition, lecrk-V.5 mutants guard cells exhibited constitutive accumulation of reactive oxygen species (ROS and inhibition of ROS production opened stomata of lecrk-V.5. LecRK-V.5 is also shown to interfere with abscisic acid-mediated stomatal closure signaling upstream of ROS production. These results provide genetic evidences that LecRK-V.5 negatively regulates stomatal immunity upstream of ROS biosynthesis. Our data reveal that plants have evolved mechanisms to reverse bacteria-mediated stomatal closure to prevent long-term effect on CO(2 uptake and photosynthesis.

Pseudomonas syringae pv. actinidiae (PSA) Isolates from Recent Bacterial Canker of Kiwifruit Outbreaks Belong to the Same Genetic Lineage

Science.gov (United States)

Taratufolo, Maria C.; Cai, Rongman; Almeida, Nalvo F.; Goodman, Tokia; Guttman, David S.; Vinatzer, Boris A.; Balestra, Giorgio M.

2012-01-01

Intercontinental spread of emerging plant diseases is one of the most serious threats to world agriculture. One emerging disease is bacterial canker of kiwi fruit (Actinidia deliciosa and A. chinensis) caused by Pseudomonas syringae pv. actinidiae (PSA). The disease first occurred in China and Japan in the 1980s and in Korea and Italy in the 1990s. A more severe form of the disease broke out in Italy in 2008 and in additional countries in 2010 and 2011 threatening the viability of the global kiwi fruit industry. To start investigating the source and routes of international transmission of PSA, genomes of strains from China (the country of origin of the genus Actinidia), Japan, Korea, Italy and Portugal have been sequenced. Strains from China, Italy, and Portugal have been found to belong to the same clonal lineage with only 6 single nucleotide polymorphisms (SNPs) in 3,453,192 bp and one genomic island distinguishing the Chinese strains from the European strains. Not more than two SNPs distinguish each of the Italian and Portuguese strains from each other. The Japanese and Korean strains belong to a separate genetic lineage as previously reported. Analysis of additional European isolates and of New Zealand isolates exploiting genome-derived markers showed that these strains belong to the same lineage as the Italian and Chinese strains. Interestingly, the analyzed New Zealand strains are identical to European strains at the tested SNP loci but test positive for the genomic island present in the sequenced Chinese strains and negative for the genomic island present in the European strains. Results are interpreted in regard to the possible direction of movement of the pathogen between countries and suggest a possible Chinese origin of the European and New Zealand outbreaks. PMID:22590555

Transcriptome changes in the phenylpropanoid pathway of Glycine max in response to Pseudomonas syringae infection

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Gonzalez Delkin O

2006-11-01

Full Text Available Abstract Background Reports of plant molecular responses to pathogenic infections have pinpointed increases in activity of several genes of the phenylpropanoid pathway leading to the synthesis of lignin and flavonoids. The majority of those findings were derived from single gene studies and more recently from several global gene expression analyses. We undertook a global transcriptional analysis focused on the response of genes of the multiple branches of the phenylpropanoid pathway to infection by the Pseudomonas syringae pv. glycinea with or without the avirulence gene avrB to characterize more broadly the contribution of the multiple branches of the pathway to the resistance response in soybean. Transcript abundance in leaves was determined from analysis of soybean cDNA microarray data and hybridizations to RNA blots with specific gene probes. Results The majority of the genes surveyed presented patterns of increased transcript accumulation. Some increased rapidly, 2 and 4 hours after inoculation, while others started to accumulate slowly by 8 – 12 hours. In contrast, transcripts of a few genes decreased in abundance 2 hours post inoculation. Most interestingly was the opposite temporal fluctuation in transcript abundance between early responsive genes in defense (CHS and IFS1 and F3H, the gene encoding a pivotal enzyme in the synthesis of anthocyanins, proanthocyanidins and flavonols. F3H transcripts decreased rapidly 2 hours post inoculation and increased during periods when CHS and IFS transcripts decreased. It was also determined that all but one (CHS4 family member genes (CHS1, CHS2, CHS3, CHS5, CHS6 and CHS7/8 accumulated higher transcript levels during the defense response provoked by the avirulent pathogen challenge. Conclusion Based on the mRNA profiles, these results show the strong bias that soybean has towards increasing the synthesis of isoflavonoid phytoalexins concomitant with the down regulation of genes required for the

Recognition of six additional cystoviruses: Pseudomonas virus phi6 is no longer the sole species of the family Cystoviridae.

Science.gov (United States)

Mäntynen, Sari; Sundberg, Lotta-Riina; Poranen, Minna M

2018-04-01

Cystoviridae is a family of bacterial viruses (bacteriophages) with a tri-segmented dsRNA genome. It includes a single genus Cystovirus, which has presently only one recognised virus species, Pseudomonas virus phi6. However, a large number of additional dsRNA phages have been isolated from various environmental samples, indicating that such viruses are more widespread and abundant than previously recognised. Six of the additional dsRNA phage isolates (Pseudomonas phages phi8, phi12, phi13, phi2954, phiNN and phiYY) have been fully sequenced. They all infect Pseudomonas species, primarily plant pathogenic Pseudomonas syringae strains. Due to the notable genetic and structural similarities with Pseudomonas phage phi6, we propose that these viruses should be included into the Cystovirus genus (and consequently into the Cystoviridae family). Here, we present an updated taxonomy of the family Cystoviridae and give a short overview of the properties of the type member phi6 as well as the putative new members of the family.

Inhibition of Pseudomonas aeruginosa virulence: characterization of the AprA-AprI interface and species selectivity.

Science.gov (United States)

Bardoel, Bart W; van Kessel, Kok P M; van Strijp, Jos A G; Milder, Fin J

2012-01-20

Pseudomonas aeruginosa secretes the virulence factor alkaline protease (AprA) to enhance its survival. AprA cleaves one of the key microbial recognition molecules, monomeric flagellin, and thereby diminishes Toll-like receptor 5 activation. In addition, AprA degrades host proteins such as complement proteins and cytokines. P. aeruginosa encodes a highly potent inhibitor of alkaline protease (AprI) that is solely located in the periplasm where it is presumed to protect periplasmic proteins against secreted AprA. We set out to study the enzyme-inhibitor interactions in more detail in order to provide a basis for future drug development. Structural and mutational studies reveal that the conserved N-terminal residues of AprI occupy the protease active site and are essential for inhibitory activity. We constructed peptides mimicking the N-terminus of AprI; however, these were incapable of inhibiting AprA-mediated flagellin cleavage. Furthermore, we expressed and purified AprI of P. aeruginosa and the homologous (37% sequence identity) AprI of Pseudomonas syringae, which remarkably show species specificity for their cognate protease. Exchange of the first five N-terminal residues between AprI of P. syringae and P. aeruginosa did not affect the observed specificity, whereas exchange of only six residues located at the AprI surface that contacts the protease did abolish specificity. These findings are elementary steps toward the design of molecules derived from the natural inhibitor of the virulence factor AprA and their use in therapeutic applications in Pseudomonas and other Gram-negative infections. Copyright © 2011 Elsevier Ltd. All rights reserved.

Gaseous 3-pentanol primes plant immunity against a bacterial speck pathogen, Pseudomonas syringae pv. tomato via salicylic acid and jasmonic acid-dependent signaling pathways in Arabidopsis.

Science.gov (United States)

Song, Geun C; Choi, Hye K; Ryu, Choong-Min

2015-01-01

3-Pentanol is an active organic compound produced by plants and is a component of emitted insect sex pheromones. A previous study reported that drench application of 3-pentanol elicited plant immunity against microbial pathogens and an insect pest in crop plants. Here, we evaluated whether 3-pentanol and the derivatives 1-pentanol and 2-pentanol induced plant systemic resistance using the in vitro I-plate system. Exposure of Arabidopsis seedlings to 10 μM and 100 nM 3-pentanol evaporate elicited an immune response to Pseudomonas syringae pv. tomato DC3000. We performed quantitative real-time PCR to investigate the 3-pentanol-mediated Arabidopsis immune responses by determining Pathogenesis-Related (PR) gene expression levels associated with defense signaling through salicylic acid (SA), jasmonic acid (JA), and ethylene signaling pathways. The results show that exposure to 3-pentanol and subsequent pathogen challenge upregulated PDF1.2 and PR1 expression. Selected Arabidopsis mutants confirmed that the 3-pentanol-mediated immune response involved SA and JA signaling pathways and the NPR1 gene. Taken together, this study indicates that gaseous 3-pentanol triggers induced resistance in Arabidopsis by priming SA and JA signaling pathways. To our knowledge, this is the first report that a volatile compound of an insect sex pheromone triggers plant systemic resistance against a bacterial pathogen.

Gaseous 3-pentanol primes plant immunity against a bacterial speck pathogen, Pseudomonas syringae pv. tomato via salicylic acid and jasmonic acid-dependent signaling pathways in Arabidopsis

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Geun Cheol eSong

2015-10-01

Full Text Available 3-Pentanol is an active organic compound produced by plants and is a component of emitted insect sex pheromones. A previous study reported that drench application of 3-pentanol elicited plant immunity against microbial pathogens and an insect pest in crop plants. Here, we evaluated whether 3-pentanol and the derivatives 1-pentanol and 2-pentanol induced plant systemic resistance using the in vitro I-plate system. Exposure of Arabidopsis seedlings to 10 M and 100 nM 3-pentanol evaporate elicited an immune response to Pseudomonas syringae pv. tomato DC3000. We performed quantitative real-time PCR to investigate the 3-pentanol-mediated Arabidopsis immune responses by determining Pathogenesis-Related (PR gene expression levels associated with defense signaling through SA, JA, and ethylene signaling pathways. The results show that exposure to 3-pentanol and subsequent pathogen challenge upregulated PDF1.2 and PR1 expression. Selected Arabidopsis mutants confirmed that the 3-pentanol-mediated immune response involved salicylic acid (SA and jasmonic acid (JA signaling pathways and the NPR1 gene. Taken together, this study indicates that gaseous 3-pentanol triggers induced resistance in Arabidopsis by priming SA and JA signaling pathways. To our knowledge, this is the first report that a volatile compound of an insect sex pheromone triggers plant systemic resistance against a bacterial pathogen.

Early Arabidopsis root hair growth stimulation by pathogenic strains of Pseudomonas syringae

Czech Academy of Sciences Publication Activity Database

Pečenková, Tamara; Janda, Martin; Ortmannová, Jitka; Hajná, Vladimíra; Stehlíková, Zuzana; Žárský, Viktor

2017-01-01

Roč. 120, č. 3 (2017), s. 437-446 ISSN 0305-7364 R&D Projects: GA ČR(CZ) GA15-14886S; GA ČR GA14-09685S Institutional support: RVO:61389030 Keywords : Arabidopsis * dde2/ein2/pad4/sid2 * exocyst * Flg22 * Pseudomonas * Root hair * vesicle trafficking Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Plant sciences, botany Impact factor: 4.041, year: 2016

Two novel cyclic peptides are key components of the antimicrobial activity of the Greenlandic isolate Pseudomonas sp. In5

DEFF Research Database (Denmark)

Hennessy, Rosanna Catherine; Phippen, Christopher; Nielsen, Kristian F.

suppressive soil, Pseudomonas sp. In5 is therefore a promising potential biocontrol agent with potent activity against plant pathogens. Studies to date have shown nunamycin and nunapeptin as key components underpinning this antimicrobial activity. Current research is focussed on unravelling the regulation...... and antimicrobial mode of action of both peptides. Functional characterisation of the LuxR-type regulatory gene nunF by targeted knock-out and complementation resulted in the loss and gain of both antimicrobial activity and peptide synthesis respectively. Located downstream of the nunamycin biosynthetic genes, nun......F shows homology to syrF from P. syringae pv. syringae involved in the regulation of the antifungal peptide syringomycin. These results show that nunF is a key component of antimicrobial activity and synthesis of nunamycin and nunapeptin....

Molecular characterization of genes of Pseudomonas sp. strain HR199 involved in bioconversion of vanillin to protocatechuate.

Science.gov (United States)

Priefert, H; Rabenhorst, J; Steinbüchel, A

1997-01-01

The gene loci vdh, vanA, and vanB, which are involved in the bioconversion of vanillin to protocatechuate by Pseudomonas sp. strain HR199 (DSM 7063), were identified as the structural genes of a novel vanillin dehydrogenase (vdh) and the two subunits of a vanillate demethylase (vanA and vanB), respectively. These genes were localized on an EcoRI fragment (E230), which was cloned from a Pseudomonas sp. strain HR199 genomic library in the cosmid pVK100. The vdh gene was identified on a subfragment (HE35) of E230, and the vanA and vanB genes were localized on a different subfragment (H110) of E230. The nucleotide sequences of fragment HE35 and part of fragment H110 were determined, revealing open reading frames of 1062, 951, and 1446 bp, representing vanA, vanB, and vdh, respectively. The vdh gene was organized in one operon together with a fourth open reading frame (ORF2), of 735 bp, which was located upstream of vdh. The deduced amino acid sequences of vanA and vanB exhibited 78.8 and 62.1% amino acid identity, respectively, to the corresponding gene products from Pseudomonas sp. strain ATCC 19151 (F. Brunel and J. Davison, J. Bacteriol. 170:4924-4930, 1988). The deduced amino acid sequence of the vdh gene exhibited up to 35.3% amino acid identity to aldehyde dehydrogenases from different sources. The deduced amino acid sequence of ORF2 exhibited up to 28.4% amino acid identity to those of enoyl coenzyme A hydratases. Escherichia coli strains harboring fragment E230 cloned in pBluescript SK- converted vanillin to protocatechuate via vanillate, indicating the functional expression of vdh, vanA, and vanB in E. coli. High expression of vdh in E. coli was achieved with HE35 cloned in pBluescript SK-. The resulting recombinant strains converted vanillin to vanillate at a rate of up to 0.3 micromol per min per ml of culture. Transfer of vanA, vanB, and vdh to Alcaligenes eutrophus and to different Pseudomonas strains, which were unable to utilize vanillin or vanillate as

Co-silencing of tomato S-adenosylhomocysteine hydrolase genes confers increased immunity against Pseudomonas syringae pv. tomato DC3000 and enhanced tolerance to drought stress

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Li Xiao Hui

2015-09-01

Full Text Available S-adenosylhomocysteine hydrolase (SAHH, catalyzing the reversible hydrolysis of S-adenosylhomocysteine to adenosine and homocysteine, is a key enzyme that maintain the cellular methylation potential in all organisms. We report here the biological functions of tomato SlSAHHs in stress response. The tomato genome contains three SlSAHH genes that encode SlSAHH proteins with high level of sequence identity. qRT-PCR analysis revealed that SlSAHHs responded with distinct expression induction patterns to Pseudomonas syringae pv. tomato (Pst DC3000 and Botrytis cinerea as well as to defense signaling hormones such as salicylic acid, jasmonic acid and a precursor of ethylene. Virus-induced gene silencing-based knockdown of individual SlSAHH gene did not affect the growth performance and the response to Pst DC3000. However, co-silencing of three SlSAHH genes using a conserved sequence led to significant inhibition of vegetable growth. The SlSAHH-co-silenced plants displayed increased resistance to Pst DC3000 but did not alter the resistance to B. cinerea. Co-silencing of SlSAHHs resulted in constitutively activated defense responses including elevated SA level, upregulated expression of defense-related and PAMP-triggered immunity marker genes and increased callose deposition and H2O2 accumulation. Furthermore, the SlSAHH-co-silenced plants also exhibited enhanced drought stress tolerance although they had relatively small roots. These data demonstrate that, in addition to the functions in growth and development, SAHHs also play important roles in regulating biotic and abiotic stress responses in plants.

Detectie en beheersing van bacterierot veroorzaakt door Pseudomonas cattleyae in Phalaenopsis

NARCIS (Netherlands)

Ludeking, D.J.W.; Hamelink, R.; Kromwijk, J.A.M.; Schenk, M.F.; Vermunt, A.; Woets, F.

2011-01-01

Phalaenopsis growers suffer from mayor losses up to 20% due to bacterial spot. This bacterial infection in caused by the Acidovorax avenae subsp. cattleyae. In practice this bacterial disease is also known as Pseudomonas. This bacterium is causing black leaf spots with a yellow border. Pseudomonas

Defining essential processes in plant pathogenesis with Pseudomonas syringae pv. tomato DC3000 disarmed polymutants and a subset of key type III effectors.

Science.gov (United States)

Wei, Hai-Lei; Collmer, Alan

2017-12-25

Pseudomonas syringae pv. tomato DC3000 and its derivatives cause disease in tomato, Arabidopsis and Nicotiana benthamiana. The primary virulence factors include a repertoire of 29 effector proteins injected into plant cells by the type III secretion system and the phytotoxin coronatine. The complete repertoire of effector genes and key coronatine biosynthesis genes have been progressively deleted and minimally reassembled to reconstitute basic pathogenic ability in N. benthamiana, and in Arabidopsis plants that have mutations in target genes that mimic effector actions. This approach and molecular studies of effector activities and plant immune system targets have highlighted a small subset of effectors that contribute to essential processes in pathogenesis. Most notably, HopM1 and AvrE1 redundantly promote an aqueous apoplastic environment, and AvrPtoB and AvrPto redundantly block early immune responses, two conditions that are sufficient for substantial bacterial growth in planta. In addition, disarmed DC3000 polymutants have been used to identify the individual effectors responsible for specific activities of the complete repertoire and to more effectively study effector domains, effector interplay and effector actions on host targets. Such work has revealed that AvrPtoB suppresses cell death elicitation in N. benthamiana that is triggered by another effector in the DC3000 repertoire, highlighting an important aspect of effector interplay in native repertoires. Disarmed DC3000 polymutants support the natural delivery of test effectors and infection readouts that more accurately reveal effector functions in key pathogenesis processes, and enable the identification of effectors with similar activities from a broad range of other pathogens that also defeat plants with cytoplasmic effectors. © 2017 BSPP AND JOHN WILEY & SONS LTD.

The Arabidopsis thaliana lectin receptor kinase LecRK-I.9 is required for full resistance to Pseudomonas syringae and affects jasmonate signalling.

Science.gov (United States)

Balagué, Claudine; Gouget, Anne; Bouchez, Olivier; Souriac, Camille; Haget, Nathalie; Boutet-Mercey, Stéphanie; Govers, Francine; Roby, Dominique; Canut, Hervé

2017-09-01

On microbial attack, plants can detect invaders and activate plant innate immunity. For the detection of pathogen molecules or cell wall damage, plants employ receptors that trigger the activation of defence responses. Cell surface proteins that belong to large families of lectin receptor kinases are candidates to function as immune receptors. Here, the function of LecRK-I.9 (At5g60300), a legume-type lectin receptor kinase involved in cell wall-plasma membrane contacts and in extracellular ATP (eATP) perception, was studied through biochemical, gene expression and reverse genetics approaches. In Arabidopsis thaliana, LecRK-I.9 expression is rapidly, highly and locally induced on inoculation with avirulent strains of Pseudomonas syringae pv. tomato (Pst). Two allelic lecrk-I.9 knock-out mutants showed decreased resistance to Pst. Conversely, over-expression of LecRK-I.9 led to increased resistance to Pst. The analysis of defence gene expression suggests an alteration of both the salicylic acid (SA) and jasmonic acid (JA) signalling pathways. In particular, LecRK-I.9 expression during plant-pathogen interaction was dependent on COI1 (CORONATINE INSENSITIVE 1) and JAR1 (JASMONATE RESISTANT 1) components, and JA-responsive transcription factors (TFs) showed altered levels of expression in plants over-expressing LecRK-I.9. A similar misregulation of these TFs was obtained by JA treatment. This study identified LecRK-I.9 as necessary for full resistance to Pst and demonstrated its involvement in the control of defence against pathogens through a regulation of JA signalling components. The role of LecRK-I.9 is discussed with regard to the potential molecular mechanisms linking JA signalling to cell wall damage and/or eATP perception. © 2016 BSPP AND JOHN WILEY & SONS LTD.

PENGARUH APLIKASI PSEUDOMONAS FLUORESCENS P60 TERHADAP MUTU PATOLOGIS, MUTU FISIOLOGIS, DAN PERTUMBUHAN BIBIT PADI IR 64

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Lisa Navitasari

2014-08-01

Full Text Available Effect of Pseudomonas fluorescens P60 on pathological and physiological quality and growth of rice IR 64  seedlings. The research objectives were (1 detection and identification of seed-borne pathogens of IR 64 rice, (2 testing Pseudomonas fluorescents P60 in inhibiting the in vitro growth of seed-borne pathogens colonies, (3 testing P. fluorescents P60 for pathological and physiological seed quality, and (4 testing P. fluorescents P60 on the growth of seedlings in the greenhouse. The results showed that some seed-borne pathogens can be found both on farmers’ IR 64 rice and factory’s; they were Aspergillus flavus, Alternaria padwickii, Pseudomonas glumae, and P. syringae. Application of P. flourescens P60 was able to inhibit the in vitrogrowth of colonies of all seed-borne pathogens, except P. syringae.  Related to pathological quality, the effect of P. flourescens P60 on percentage of seed-borne pathogens attack did not significantly different from that of benomil but smaller than distilled water. On the physiological quality of seeds, treatment of P. flourescens P60 has the same effect with benomil and distilled water, with  germination rate was more than 80%. In the greenhouse study,treatment of seed immersion time  in P. flourescens P60 suspension showed that the effect of immersion time as long as15 minutes and 25 minutes on  seedling height, root length, and seedling dry weightdid not significantly different. were. However, 25 minutes immersion time resulted in fresh seedling weight and root dry weight higher than that of 15 minutes immersion time.

Investigation of intercellular salicylic acid accumulation during compatible and incompatible Arabidopsis-pseudomonas syringae interactions using a fast neutron-generated mutant allele of EDS5 identified by genetic mapping and whole-genome sequencing.

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Jessie L Carviel

Full Text Available A whole-genome sequencing technique developed to identify fast neutron-induced deletion mutations revealed that iap1-1 is a new allele of EDS5 (eds5-5. RPS2-AvrRpt2-initiated effector-triggered immunity (ETI was compromised in iap1-1/eds5-5 with respect to in planta bacterial levels and the hypersensitive response, while intra- and intercellular free salicylic acid (SA accumulation was greatly reduced, suggesting that SA contributes as both an intracellular signaling molecule and an antimicrobial agent in the intercellular space during ETI. During the compatible interaction between wild-type Col-0 and virulent Pseudomonas syringae pv. tomato (Pst, little intercellular free SA accumulated, which led to the hypothesis that Pst suppresses intercellular SA accumulation. When Col-0 was inoculated with a coronatine-deficient strain of Pst, high levels of intercellular SA accumulation were observed, suggesting that Pst suppresses intercellular SA accumulation using its phytotoxin coronatine. This work suggests that accumulation of SA in the intercellular space is an important component of basal/PAMP-triggered immunity as well as ETI to pathogens that colonize the intercellular space.

Pseudomonas syringae evades host immunity by degrading flagellin monomers with alkaline protease AprA

NARCIS (Netherlands)

Pel, Michiel J C; van Dijken, Anja J H; Bardoel, Bart W; Seidl, Michael F; van der Ent, Sjoerd; van Strijp, Jos A G; Pieterse, Corné M J

Bacterial flagellin molecules are strong inducers of innate immune responses in both mammals and plants. The opportunistic pathogen Pseudomonas aeruginosa secretes an alkaline protease called AprA that degrades flagellin monomers. Here, we show that AprA is widespread among a wide variety of

Pseudomonas syringae evades host Immunity by degrading flagellin monomers with alkaline protease AprA

NARCIS (Netherlands)

Pel, M.J.C.; Van Dijken, A.J.H.; Bardoel, B.W.; Seidl, M.F; Van der Ent, S.; Van Strijp, J.A.G.

2014-01-01

Bacterial flagellin molecules are strong inducers of innate immune responses in both mammals and plants. The opportunistic pathogen Pseudomonas aeruginosa secretes an alkaline protease called AprA that degrades flagellin monomers. Here, we show that AprA is widespread among a wide variety of

A Carbenicillin R Factor from Pseudomonas aeruginosa | van ...

African Journals Online (AJOL)

Of 64 carbenicillin-resistant Pseudomonas aeruginosa strains 40 transferred this resistance to Escherichia coli. R factor RP-638 isolated from Ps. aeruginosa strain 638 conferred resistance to ampicillin, carbenicillin, kanamycin, neomycin and tetracycline. This R factor was transferred at frequencies 01 10-7 to 10-4 between ...

In vitro evaluering van die effektiwiteit van vyf plante wat tradisioneel teen seksueel oordraagbare siektes gebruik word

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H. Swart

2002-09-01

Full Text Available Tot soveel as 60% van die Suid-Afrikaanse bevolking raadpleeg tradisionele genesers vir siektetoestande, insluitende seksueel oordraagbare siektes (SOS. Medisinale plante speel ’n belangrike rol in die behandeling van SOS deur tradisionele genesers, maar sonder enige wetenskaplike bewyse van effektiwiteit. Vir hierdie studie is 5 plante vanuit die literatuur gekies op grond van hul gebruik deur tradisionele genesers vir die behandeling van SOS. Siftingstoetse vir die bepaling van aktiwiteit teen bakterieë en teen SOS is op die plante uitgevoer. Die plante was Clematis brachiata, Elephantorrhiza elephantina, Lepidium bonariense, Ranunculus multifidus en Typha capensis. Siftingstoetse is uitgevoer met die organismes Candida albicans, Neisseria gonorrhoeae en Haemophilus ducreyi wat met SOS geassosieer word, terwyl Bacillus subtilus, Micrococcus luteus, Staphylococcus aureus, Enterobacter sp., Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa en Aspergillus niger ook in die siftingstoetse ingesluit is. Slegs Lepidium bonariense het aktiwiteit teen die gebruikte organismes getoon. Dit is dus duidelik dat daar ’n behoefte bestaan om die effektiwiteit van medisinale plante wetenskaplik te bepaal en te kommunikeer.

Overexpression of Nictaba-Like Lectin Genes from Glycine max Confers Tolerance towards Pseudomonas syringae Infection, Aphid Infestation and Salt Stress in Transgenic Arabidopsis Plants

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Sofie Van Holle

2016-10-01

Full Text Available Plants have evolved a sophisticated immune system that allows them to recognize invading pathogens by specialized receptors. Carbohydrate-binding proteins or lectins are part of this immune system and especially the lectins that reside in the nucleocytoplasmic compartment are known to be implicated in biotic and abiotic stress responses. The class of Nictaba-like lectins (NLL groups all proteins with homology to the tobacco (Nicotiana tabacum lectin, known as a stress-inducible lectin. Here we focus on two Nictaba homologs from soybean (Glycine max, referred to as GmNLL1 and GmNLL2. Confocal laser scanning microscopy of fusion constructs with the green fluorescent protein either transiently expressed in Nicotiana benthamiana leaves or stably transformed in tobacco BY-2 suspension cells revealed a nucleocytoplasmic localization for the GmNLLs under study. RT-qPCR analysis of the transcript levels for the Nictaba-like lectins in soybean demonstrated that the genes are expressed in several tissues throughout the development of the plant. Furthermore, it was shown that salt treatment, Phytophthora sojae infection and Aphis glycines infestation trigger the expression of particular NLL genes. Stress experiments with Arabidopsis lines overexpressing the NLLs from soybean yielded an enhanced tolerance of the plant towards bacterial infection (Pseudomonas syringae, insect infestation (Myzus persicae and salinity. Our data showed a better performance of the transgenic lines compared to wild type plants, indicating that the NLLs from soybean are implicated in the stress response. These data can help to further elucidate the physiological importance of the Nictaba-like lectins from soybean, which can ultimately lead to the design of crop plants with a better tolerance to changing environmental conditions.

Comparative Genomic Analyses of Multiple Pseudomonas Strains Infecting Corylus avellana Trees Reveal the Occurrence of Two Genetic Clusters with Both Common and Distinctive Virulence and Fitness Traits

Science.gov (United States)

Marcelletti, Simone; Scortichini, Marco

2015-01-01

The European hazelnut (Corylus avellana) is threatened in Europe by several pseudomonads which cause symptoms ranging from twig dieback to tree death. A comparison of the draft genomes of nine Pseudomonas strains isolated from symptomatic C. avellana trees was performed to identify common and distinctive genomic traits. The thorough assessment of genetic relationships among the strains revealed two clearly distinct clusters: P. avellanae and P. syringae. The latter including the pathovars avellanae, coryli and syringae. Between these two clusters, no recombination event was found. A genomic island of approximately 20 kb, containing the hrp/hrc type III secretion system gene cluster, was found to be present without any genomic difference in all nine pseudomonads. The type III secretion system effector repertoires were remarkably different in the two groups, with P. avellanae showing a higher number of effectors. Homologue genes of the antimetabolite mangotoxin and ice nucleation activity clusters were found solely in all P. syringae pathovar strains, whereas the siderophore yersiniabactin was only present in P. avellanae. All nine strains have genes coding for pectic enzymes and sucrose metabolism. By contrast, they do not have genes coding for indolacetic acid and anti-insect toxin. Collectively, this study reveals that genomically different Pseudomonas can converge on the same host plant by suppressing the host defence mechanisms with the use of different virulence weapons. The integration into their genomes of a horizontally acquired genomic island could play a fundamental role in their evolution, perhaps giving them the ability to exploit new ecological niches. PMID:26147218

Differential modulation of plant immune responses by diverse members of the Pseudomonas savastanoi pv. savastanoi HopAF type III effector family.

Science.gov (United States)

Castañeda-Ojeda, M Pilar; López-Solanilla, Emilia; Ramos, Cayo

2017-06-01

The Pseudomonas savastanoi pv. savastanoi NCPPB 3335 type III secretion system (T3SS) effector repertoire includes 33 candidates, seven of which translocate into host cells and interfere with plant defences. The present study was performed to investigate the co-existence of both plasmid- and chromosomal-encoded members of the HopAF effector family, HopAF1-1 and HopAF1-2, respectively, in the genome of NCPPB 3335. Here, we show that the HopAF1 paralogues are widely distributed in the Pseudomonas syringae complex, where HopAF1-1 is most similar to the homologues encoded by other P. syringae pathovars infecting woody hosts that belong to phylogroups 1 and 3. We show that the expression of both HopAF1-1 and HopAF-2 is transcriptionally dependent on HrpL and demonstrate their delivery into Nicotiana tabacum leaves. Although the heterologous delivery of either HopAF1-1 or HopAF1-2 significantly suppressed the production of defence-associated reactive oxygen species levels, only HopAF1-2 reduced the levels of callose deposition. Moreover, the expression of HopAF1-2 by functionally effectorless P. syringae pv. tomato DC3000D28E completely inhibited the hypersensitive response in tobacco and significantly increased the competitiveness of the strain in Nicotiana benthamiana. Despite their functional differences, subcellular localization studies reveal that green fluorescent protein (GFP) fusions to either HopAF1-1 or HopAF1-2 are targeted to the plasma membrane when they are expressed in plant cells, a process that is completely dependent on the integrity of their N-myristoylation motif. Our results further support the notion that highly similar T3SS effectors might differentially interact with diverse plant targets, even when they co-localize in the same cell compartment. © 2016 BSPP AND JOHN WILEY & SONS LTD.

Integration Host Factor (IHF binds to the promoter region of the phtD operon involved in phaseolotoxin synthesis in P. syringae pv. phaseolicola NPS3121

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Álvarez-Morales Ariel

2011-05-01

Full Text Available Abstract Background Pseudomonas syringae pv. phaseolicola, the causal agent of halo blight disease in beans, produces a toxin known as phaseolotoxin, in whose synthesis participate a group of genes organized within the genome in a region known as the "Pht cluster". This region, which is thought to have been acquired by horizontal gene transfer, includes 5 transcriptional units, two monocistronic (argK, phtL and three polycistronic (phtA, phtD, phtM, whose expression is temperature dependent. So far, the regulatory mechanisms involved in phaseolotoxin synthesis have not been elucidated and the only well-established fact is the requirement of low temperatures for its synthesis. In this work, we searched for regulatory proteins that could be involved in phaseolotoxin synthesis, focusing on the regulation of the phtD operon. Results In this study we identified the global regulator IHF (Integration Host Factor, which binds to the promoter region of the phtD operon, exerting a negative effect on the expression of this operon. This is the first regulatory protein identified as part of the phaseolotoxin synthesis system. Our findings suggest that the Pht cluster was similarly regulated in the ancestral cluster by IHF or similar protein, and integrated into the global regulatory mechanism of P. syringae pv. phaseolicola, after the horizontal gene transfer event by using the host IHF protein. Conclusion This study identifies the IHF protein as one element involved in the regulation of phaseolotoxin synthesis in P. syringae pv. phaseolicola NPS3121 and provides new insights into the regulatory mechanisms involved in phaseolotoxin production.

Bacterial canker on kiwifruit in Italy: Anatomical changes in the wood and in the primary infection sites

NARCIS (Netherlands)

Renzi, M.; Copini, P.; Taddei, A.R.; Rossetti, A.; Gallipoli, L.; Mazzaglia, A.; Balestra, G.M.

2012-01-01

The bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae is a severe threat to kiwifruit production worldwide. Many aspects of P. syringae pv. actinidiae biology and epidemiology still require in-depth investigation. The infection by and spread of P. syringae pv. actinidiae in

Development of a Multiple Loci Variable Number of Tandem Repeats Analysis (MLVA) to Unravel the Intra-Pathovar Structure of Pseudomonas syringae pv. actinidiae Populations Worldwide

Science.gov (United States)

Ciarroni, Serena; Gallipoli, Lorenzo; Taratufolo, Maria C.; Butler, Margi I.; Poulter, Russell T. M.; Pourcel, Christine; Vergnaud, Gilles; Balestra, Giorgio M.; Mazzaglia, Angelo

2015-01-01

The bacterial canker of kiwifruit by Pseudomonas syringae pv. actinidiae is an emblematic example of a catastrophic disease of fruit crops. In 2008 a new, extremely virulent form of the pathogen emerged and rapidly devastated many Actinidia spp. orchards all over the world. In order to understand differences in populations within this pathovar and to elucidate their diffusion and movements on world scale, it is necessary to be able to quickly and on a routine basis compare new isolates with previous records. In this report a worldwide collection of 142 strains was analyzed by MLVA, chosen as investigative technique for its efficacy, reproducibility, simplicity and low cost. A panel of 13 Variable Number of Tandem Repeats (VNTR) loci was identified and used to describe the pathogen population. The MLVA clustering is highly congruent with the population structure as previously established by other molecular approaches including whole genome sequencing and correlates with geographic origin, time of isolation and virulence. For convenience, we divided the VNTR loci in two panels. Panel 1 assay, using six loci, recognizes 23 different haplotypes, clustered into ten complexes with highest congruence with previous classifications. Panel 2, with seven VNTR loci, provides discriminatory power. Using the total set of 13 VNTR loci, 58 haplotypes can be distinguished. The recent hypervirulent type shows very limited diversity and includes, beside the strains from Europe, New Zealand and Chile, a few strains from Shaanxi, China. A broad genetic variability is observed in China, but different types are also retrievable in Japan and Korea. The low virulent strains cluster together and are very different from the other MLVA genotypes. Data were used to generate a public database in MLVAbank. MLVA represents a very promising first-line assay for large-scale routine genotyping, prior to whole genome sequencing of only the most relevant samples. PMID:26262683

Rhizosphere-associated Pseudomonas induce systemic resistance to herbivores at the cost of susceptibility to bacterial pathogens.

Science.gov (United States)

Haney, Cara H; Wiesmann, Christina L; Shapiro, Lori R; Melnyk, Ryan A; O'Sullivan, Lucy R; Khorasani, Sophie; Xiao, Li; Han, Jiatong; Bush, Jenifer; Carrillo, Juli; Pierce, Naomi E; Ausubel, Frederick M

2017-10-31

Plant-associated soil microbes are important mediators of plant defence responses to diverse above-ground pathogen and insect challengers. For example, closely related strains of beneficial rhizosphere Pseudomonas spp. can induce systemic resistance (ISR), systemic susceptibility (ISS) or neither against the bacterial foliar pathogen Pseudomonas syringae pv. tomato DC3000 (Pto DC3000). Using a model system composed of root-associated Pseudomonas spp. strains, the foliar pathogen Pto DC3000 and the herbivore Trichoplusia ni (cabbage looper), we found that rhizosphere-associated Pseudomonas spp. that induce either ISS and ISR against Pto DC3000 all increased resistance to herbivory by T. ni. We found that resistance to T. ni and resistance to Pto DC3000 are quantitative metrics of the jasmonic acid (JA)/salicylic acid (SA) trade-off and distinct strains of rhizosphere-associated Pseudomonas spp. have distinct effects on the JA/SA trade-off. Using genetic analysis and transcriptional profiling, we provide evidence that treatment of Arabidopsis with Pseudomonas sp. CH267, which induces ISS against bacterial pathogens, tips the JA/SA trade-off towards JA-dependent defences against herbivores at the cost of a subset of SA-mediated defences against bacterial pathogens. In contrast, treatment of Arabidopsis with the ISR strain Pseudomonas sp. WCS417 disrupts JA/SA antagonism and simultaneously primes plants for both JA- and SA-mediated defences. Our findings show that ISS against the bacterial foliar pathogens triggered by Pseudomonas sp. CH267, which is a seemingly deleterious phenotype, may in fact be an adaptive consequence of increased resistance to herbivory. Our work shows that pleiotropic effects of microbiome modulation of plant defences are important to consider when using microbes to modify plant traits in agriculture. © 2017 John Wiley & Sons Ltd.

An insight into the photodynamic approach versus copper formulations in the control of Pseudomonas syringae pv. actinidiae in kiwi plants.

Science.gov (United States)

Jesus, Vânia; Martins, Diana; Branco, Tatiana; Valério, Nádia; Neves, Maria G P M S; Faustino, Maria A F; Reis, Luís; Barreal, Esther; Gallego, Pedro P; Almeida, Adelaide

2018-02-14

In the last decade, the worldwide production of kiwi fruit has been highly affected by Pseudomonas syringae pv. actinidiae (Psa), a phytopathogenic bacterium; this has led to severe economic losses that are seriously affecting the kiwi fruit trade. The available treatments for this disease are still scarce, with the most common involving frequently spraying the orchards with copper derivatives, in particular cuprous oxide (Cu 2 O). However, these copper formulations should be avoided due to their high toxicity; therefore, it is essential to search for new approaches for controlling Psa. Antimicrobial photodynamic therapy (aPDT) may be an alternative approach to inactivate Psa. aPDT consists in the use of a photosensitizer molecule (PS) that absorbs light and by transference of the excess of energy or electrons to molecular oxygen forms highly reactive oxygen species (ROS) that can affect different molecular targets, thus being very unlikely to lead to the development of microbe resistance. The aim of the present study was to evaluate the effectiveness of aPDT to photoinactivate Psa, using the porphyrin Tetra-Py + -Me and different light intensities. The degree of inactivation of Psa was assessed using the PS at 5.0 μM under low irradiance (4.0 mW cm -2 ). Afterward, ex vivo experiments, using artificially contaminated kiwi leaves, were conducted with a PS at 50 μM under 150 mW cm -2 and sunlight irradiation. A reduction of 6 log in the in vitro assays after 90 min of irradiation was observed. In the ex vivo tests, the decrease was lower, approximately 1.8 log reduction at an irradiance of 150 mW cm -2 , 1.2 log at 4.0 mW cm -2 , and 1.5 log under solar radiation. However, after three successive cycles of treatment under 150 mW cm -2 , a 4 log inactivation was achieved. No negative effects were observed on leaves after treatment. Assays using Cu 2 O were also performed at the recommended concentration by law (50 g h L -1 ) and at concentrations 10 times

Draft Genome Sequence Analysis of a Pseudomonas putida W15Oct28 Strain with Antagonistic Activity to Gram-Positive and Pseudomonas sp. Pathogens

Science.gov (United States)

Ye, Lumeng; Hildebrand, Falk; Dingemans, Jozef; Ballet, Steven; Laus, George; Matthijs, Sandra; Berendsen, Roeland; Cornelis, Pierre

2014-01-01

Pseudomonas putida is a member of the fluorescent pseudomonads known to produce the yellow-green fluorescent pyoverdine siderophore. P. putida W15Oct28, isolated from a stream in Brussels, was found to produce compound(s) with antimicrobial activity against the opportunistic pathogens Staphylococcus aureus, Pseudomonas aeruginosa, and the plant pathogen Pseudomonas syringae, an unusual characteristic for P. putida. The active compound production only occurred in media with low iron content and without organic nitrogen sources. Transposon mutants which lost their antimicrobial activity had the majority of insertions in genes involved in the biosynthesis of pyoverdine, although purified pyoverdine was not responsible for the antagonism. Separation of compounds present in culture supernatants revealed the presence of two fractions containing highly hydrophobic molecules active against P. aeruginosa. Analysis of the draft genome confirmed the presence of putisolvin biosynthesis genes and the corresponding lipopeptides were found to contribute to the antimicrobial activity. One cluster of ten genes was detected, comprising a NAD-dependent epimerase, an acetylornithine aminotransferase, an acyl CoA dehydrogenase, a short chain dehydrogenase, a fatty acid desaturase and three genes for a RND efflux pump. P. putida W15Oct28 genome also contains 56 genes encoding TonB-dependent receptors, conferring a high capacity to utilize pyoverdines from other pseudomonads. One unique feature of W15Oct28 is also the presence of different secretion systems including a full set of genes for type IV secretion, and several genes for type VI secretion and their VgrG effectors. PMID:25369289

The effects of hyperosmosis or high pH on a dual-species biofilm of Enterococcus faecalis and Pseudomonas aeruginosa : an in vitro study

NARCIS (Netherlands)

van der Waal, S. V.; van der Sluis, L. W. M.; Ozok, A. R.; Exterkate, R. A. M.; van Marle, J.; Wesselink, P. R.; de Soet, J. J.

2011-01-01

van der Waal SV, van der Sluis LWM, Ozok AR, Exterkate RAM, van Marle J, Wesselink PR, de Soet JJ. The effects of hyperosmosis or high pH on a dual-species biofilm of Enterococcus faecalis and Pseudomonas aeruginosa: an in vitro study. International Endodontic Journal, 44, 11101117, 2011. Aim To

TaNAC1 acts as a negative regulator of stripe rust resistance in wheat, enhances susceptibility to Pseudomonas syringae, and promotes lateral root development in transgenic Arabidopsis thaliana

Directory of Open Access Journals (Sweden)

Fengtao eWang

2015-02-01

Full Text Available Plant-specific NAC transcription factors constitute a large family and play important roles in regulating plant developmental processes and responses to environmental stresses, but only some of them have been investigated for effects on disease reaction in cereal crops. Virus-induced gene silencing (VIGS is an effective strategy for rapid functional analysis of genes in plant tissues. In this study, TaNAC1, encoding a new member of the NAC1 subgroup, was cloned from bread wheat and characterized. It is a transcription factor localized in the cell nucleus, and contains an activation domain in its C-terminal. TaNAC1 was strongly expressed in wheat roots and was involved in responses to infection by the obligate pathogen Puccinia striiformis f. sp. tritici and defense-related hormone treatments such as salicylic acid, methyl jasmonate and ethylene. Knockdown of TaNAC1 with barley stripe mosaic virus-induced gene silencing (BSMV-VIGS enhanced stripe rust resistance. TaNAC1-overexpression in Arabidopsis plants gave enhanced susceptibility, attenuated systemic-acquired resistance to Pseudomonas syringae DC3000, and promoted lateral root development. Jasmonic acid-signaling pathway genes PDF1.2 and ORA59 were constitutively expressed in transgenic plants. TaNAC1 overexpression suppressed the expression levels of resistance-related genes PR1 and PR2 involved in SA signaling and AtWRKY70, which functions as a connection node between the JA- and SA-signaling pathways. Collectively, TaNAC1 is a novel NAC member of the NAC1 subgroup, negatively regulates plant disease resistance, and may modulate plant JA- and SA-signaling defense cascades.

Isolation of Fungal Species from Fermentating Pearl Millet Gruel and ...

African Journals Online (AJOL)

Escherichia coli, Staphylococcus aureus, Bacillus cereus, Bacillus lichieniformis, Salmonella spp., Pseudomonas fluorescens, Pseudomonas aeruginosa, Pseudomonas syringae, Proteus sp. and Serratia sp. were utilized as indicator organisms. Secondary metabolites were also extracted from the respective moulds and ...

Characterization of the biocontrol activity of pseudomonas fluorescens strain X reveals novel genes regulated by glucose.

Directory of Open Access Journals (Sweden)

Gerasimos F Kremmydas

Full Text Available Pseudomonas fluorescens strain X, a bacterial isolate from the rhizosphere of bean seedlings, has the ability to suppress damping-off caused by the oomycete Pythium ultimum. To determine the genes controlling the biocontrol activity of strain X, transposon mutagenesis, sequencing and complementation was performed. Results indicate that, biocontrol ability of this isolate is attributed to gcd gene encoding glucose dehydrogenase, genes encoding its co-enzyme pyrroloquinoline quinone (PQQ, and two genes (sup5 and sup6 which seem to be organized in a putative operon. This operon (named supX consists of five genes, one of which encodes a non-ribosomal peptide synthase. A unique binding site for a GntR-type transcriptional factor is localized upstream of the supX putative operon. Synteny comparison of the genes in supX revealed that they are common in the genus Pseudomonas, but with a low degree of similarity. supX shows high similarity only to the mangotoxin operon of Ps. syringae pv. syringae UMAF0158. Quantitative real-time PCR analysis indicated that transcription of supX is strongly reduced in the gcd and PQQ-minus mutants of Ps. fluorescens strain X. On the contrary, transcription of supX in the wild type is enhanced by glucose and transcription levels that appear to be higher during the stationary phase. Gcd, which uses PQQ as a cofactor, catalyses the oxidation of glucose to gluconic acid, which controls the activity of the GntR family of transcriptional factors. The genes in the supX putative operon have not been implicated before in the biocontrol of plant pathogens by pseudomonads. They are involved in the biosynthesis of an antimicrobial compound by Ps. fluorescens strain X and their transcription is controlled by glucose, possibly through the activity of a GntR-type transcriptional factor binding upstream of this putative operon.

Bacterial Leaf Spot of Parsley: Characterization of a New Disease

Science.gov (United States)

Since 2002, a severe leaf spot disease on parsley has occurred throughout central coastal California and particularly in Monterey County. Two different bacterial pathogens (Pseudomonas syringae pv. apii, and P. syringae pv. coriandricola) have been associated these outbreaks on parsley. Our research...

Show us your spots! Researchers need samples of bacterial leaf spots on celery, cilantro, parsley, and other crops.

Science.gov (United States)

Since 2002, a severe leaf spot disease on parsley has occurred throughout central coastal California and particularly in Monterey County. Three different bacterial pathogens (Pseudomonas syringae pv. apii, P. syringae pv. coriandricola and an organism very closely related to P. viridiflava) have bee...

Pseudomonas cichorii as the causal agent of midrib rot, an emerging disease of greenhouse-grown butterhead lettuce in Flanders.

Science.gov (United States)

Cottyn, Bart; Heylen, Kim; Heyrman, Jeroen; Vanhouteghem, Katrien; Pauwelyn, Ellen; Bleyaert, Peter; Van Vaerenbergh, Johan; Höfte, Monica; De Vos, Paul; Maes, Martine

2009-05-01

Bacterial midrib rot of greenhouse-grown butterhead lettuce (Lactuca sativa L. var. capitata) is an emerging disease in Flanders (Belgium) and fluorescent pseudomonads are suspected to play an important role in the disease. Isolations from infected lettuces, collected from 14 commercial greenhouses in Flanders, yielded 149 isolates that were characterized polyphasically, which included morphological characteristics, pigmentation, pathogenicity tests by both injection and spraying of lettuce, LOPAT characteristics, FAME analysis, BOX-PCR fingerprinting, 16S rRNA and rpoB gene sequencing, as well as DNA-DNA hybridization. Ninety-eight isolates (66%) exhibited a fluorescent pigmentation and were associated with the genus Pseudomonas. Fifty-five of them induced an HR+ (hypersensitive reaction in tobacco leaves) response. The other 43 fluorescent isolates were most probably saprophytic bacteria and about half of them were able to cause rot on potato tuber slices. BOX-PCR genomic fingerprinting was used to assess the genetic diversity of the Pseudomonas midrib rot isolates. The delineated BOX-PCR patterns matched quite well with Pseudomonas morphotypes defined on the basis of colony appearance and variation in fluorescent pigmentation. 16S rRNA and rpoB gene sequence analyses allowed most of the fluorescent isolates to be allocated to Pseudomonas, and they belonged to either the Pseudomonas fluorescens group, Pseudomonas putida group, or the Pseudomonas cichorii/syringae group. In particular, the isolates allocated to this latter group constituted the vast majority of HR+ isolates and were identified as P. cichorii by DNA-DNA hybridization. They were demonstrated by spray-inoculation tests on greenhouse-grown lettuce to induce the midrib rot disease and could be re-isolated from lesions of inoculated plants. Four HR+ non-fluorescent isolates associated with one sample that showed an atypical midrib rot were identified as Dickeya sp.

A rapid seedling resistance assay identifies wild tomato lines that are resistant to Psuedomonas syringe pv. tomato race 1

Science.gov (United States)

Bacterial speck caused by Pseudomonas syringae has historically been controlled by the Pto/Prf gene cluster. Emerging strains like P. syringae pv. tomato race 1 overcome resistance conferred by Pto/Prf, and can cause serious crop loss under appropriate environmental conditions. We developed a rapid ...

Two small RNAs, CrcY and CrcZ, act in concert to sequester the Crc global regulator in Pseudomonas putida, modulating catabolite repression.

Science.gov (United States)

Moreno, Renata; Fonseca, Pilar; Rojo, Fernando

2012-01-01

The Crc protein is a translational repressor that recognizes a specific target at some mRNAs, controlling catabolite repression and co-ordinating carbon metabolism in pseudomonads. In Pseudomonas aeruginosa, the levels of free Crc protein are controlled by CrcZ, a sRNA that sequesters Crc, acting as an antagonist. We show that, in Pseudomonas putida, the levels of free Crc are controlled by CrcZ and by a novel 368 nt sRNA named CrcY. CrcZ and CrcY, which contain six potential targets for Crc, were able to bind Crc specifically in vitro. The levels of CrcZ and CrcY were low under conditions generating a strong catabolite repression, and increased strongly when catabolite repression was absent. Deletion of either crcZ or crcY had no effect on catabolite repression, but the simultaneous absence of both sRNAs led to constitutive catabolite repression that compromised growth on some carbon sources. Overproduction of CrcZ or CrcY significantly reduced repression. We propose that CrcZ and CrcY act in concert, sequestering and modulating the levels of free Crc according to metabolic conditions. The CbrA/CbrB two-component system activated crcZ transcription, but had little effect on crcY. CrcY was detected in P. putida, Pseudomonas fluorescens and Pseudomonas syringae, but not in P. aeruginosa. © 2011 Blackwell Publishing Ltd.

Characterisation of bacterial brown spot pathogen from dry bean ...

African Journals Online (AJOL)

Pseudomonas syringae pv. syringae (Pss) causes bacterial brown spot (BBS) of beans (Phaseolus vulgaris L.), with yield losses of up to 55% in South Africa. Pss has a wide host range and for many of these, the pathogen has been biochemically and genetically characterised. However, few studies have been conducted on ...

Boomkwekerij op veen : bedrijfseconomische resultaten biologische boomkwekerij

NARCIS (Netherlands)

Snoek, B.; Schuring, W.; Leijden, van J.P.H.

2003-01-01

Resultaten van een onderzoek op PPO-locatie Boskoop naar de bedrijfseconomische mogelijkheden van biologische boomteelt. Zes gewassen uit de gewasgroep siergewassen (Acer, Buxus, Magnolia, Mahonia, Prunus en Syringa) werden in twee jaar opgekweekt van plantgoed naar leverbaar materiaal. In tabellen

The Mediator subunit SFR6/MED16 controls defence gene expression mediated by salicylic acid and jasmonate responsive pathways.

Science.gov (United States)

Wathugala, Deepthi L; Hemsley, Piers A; Moffat, Caroline S; Cremelie, Pieter; Knight, Marc R; Knight, Heather

2012-07-01

• Arabidopsis SENSITIVE TO FREEZING6 (SFR6) controls cold- and drought-inducible gene expression and freezing- and osmotic-stress tolerance. Its identification as a component of the MEDIATOR transcriptional co-activator complex led us to address its involvement in other transcriptional responses. • Gene expression responses to Pseudomonas syringae, ultraviolet-C (UV-C) irradiation, salicylic acid (SA) and jasmonic acid (JA) were investigated in three sfr6 mutant alleles by quantitative real-time PCR and susceptibility to UV-C irradiation and Pseudomonas infection were assessed. • sfr6 mutants were more susceptible to both Pseudomonas syringae infection and UV-C irradiation. They exhibited correspondingly weaker PR (pathogenesis-related) gene expression than wild-type Arabidopsis following these treatments or after direct application of SA, involved in response to both UV-C and Pseudomonas infection. Other genes, however, were induced normally in the mutants by these treatments. sfr6 mutants were severely defective in expression of plant defensin genes in response to JA; ectopic expression of defensin genes was provoked in wild-type but not sfr6 by overexpression of ERF5. • SFR6/MED16 controls both SA- and JA-mediated defence gene expression and is necessary for tolerance of Pseudomonas syringae infection and UV-C irradiation. It is not, however, a universal regulator of stress gene transcription and is likely to mediate transcriptional activation of specific regulons only. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

Knots Untie: Molecular Determinants Involved in Knot Formation Induced by Pseudomonas savastanoi in Woody Hosts

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Eloy Caballo-Ponce

2017-06-01

Full Text Available The study of the molecular basis of tree diseases is lately receiving a renewed attention, especially with the emerging perception that pathogens require specific pathogenicity and virulence factors to successfully colonize woody hosts. Pathosystems involving woody plants are notoriously difficult to study, although the use of model bacterial strains together with genetically homogeneous micropropagated plant material is providing a significant impetus to our understanding of the molecular determinants leading to disease. The gammaproteobacterium Pseudomonas savastanoi belongs to the intensively studied Pseudomonas syringae complex, and includes three pathogenic lineages causing tumorous overgrowths (knots in diverse economically relevant trees and shrubs. As it occurs with many other bacteria, pathogenicity of P. savastanoi is dependent on a type III secretion system, which is accompanied by a core set of at least 20 effector genes shared among strains isolated from olive, oleander, and ash. The induction of knots of wild-type size requires that the pathogen maintains adequate levels of diverse metabolites, including the phytohormones indole-3-acetic acid and cytokinins, as well as cyclic-di-GMP, some of which can also regulate the expression of other pathogenicity and virulence genes and participate in bacterial competitiveness. In a remarkable example of social networking, quorum sensing molecules allow for the communication among P. savastanoi and other members of the knot microbiome, while at the same time are essential for tumor formation. Additionally, a distinguishing feature of bacteria from the P. syringae complex isolated from woody organs is the possession of a 15 kb genomic island (WHOP carrying four operons and three other genes involved in degradation of phenolic compounds. Two of these operons mediate the catabolism of anthranilate and catechol and, together with another operon, are required for the induction of full-size tumors

ORF Alignment: NC_004578 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available ... [Pseudomonas syringae pv. tomato str. DC3000] ... Length = 157 ... Query: 238 GHGIPLSIHDAHGLDKTLEHVVSEIQRVHPSRLIRSN...IGALELIRCDHERIAQLLSNLVS 297 ... GHGIPLSIHDAHGLDKTLEHVVSEIQRVHPSRLIRSN...IGALELIRCDHERIAQLLSNLVS Sbjct: 1 ... GHGIPLSIHDAHGLDKTLEHVVSEIQRVHPSRLIRSNIGALELIRCDHERIAQLLSNLV

Rôle du couvre-sol dans le développement du chancre bactérien dans les vergers d’abricotiers

OpenAIRE

Peyre, Manon

2017-01-01

Le genre Pseudomonas, inclut plusieurs espèces de bactéries phytopathogènes, comme les Pseudomonas syringae qui provoque la bactériose, maladie conduisant généralement à la mort des arbres fruitiers. A l’heure actuelle, les moyens de lutte contre P. syringae sont très réduits ou inexistants. Ainsi, des méthodes alternatives ou le rôle de certains éléments comme la présence de réservoirs de la bactérie sont en cours d’étude. Partant de l’hypothèse que le couvre-sol pourrait être une source...

Regulation of disease-responsive genes mediated by epigenetic factors: interaction of Arabidopsis-Pseudomonas.

Science.gov (United States)

De-La-Peña, Clelia; Rangel-Cano, Alicia; Alvarez-Venegas, Raúl

2012-05-01

Genes in eukaryotic organisms function within the context of chromatin, and the mechanisms that modulate the structure of chromatin are defined as epigenetic. In Arabidopsis, pathogen infection induces the expression of at least one histone deacetylase, suggesting that histone acetylation/deacetylation has an important role in the pathogenic response in plants. How/whether histone methylation affects gene response to pathogen infection is unknown. To gain a better understanding of the epigenetic mechanisms regulating the interaction between Pseudomonas syringae and Arabidopsis thaliana, we analysed three different Arabidopsis ash1-related (absent, small or homeotic discs 1) mutants. We found that the loss of function of ASHH2 and ASHR1 resulted in faster hypersensitive responses (HRs) to both mutant (hrpA) and pathogenic (DC3000) strains of P. syringae, whereas control (Col-0) and ashr3 mutants appeared to be more resistant to the infection after 2 days. Furthermore, we showed that, in the ashr3 background, the PR1 gene (PATHOGENESIS-RELATED GENE 1) displayed the highest expression levels on infection with DC3000, correlating with increased resistance against this pathogen. Our results show that, in both the ashr1 and ashh2 backgrounds, the histone H3 lysine 4 dimethylation (H3K4me2) levels decreased at the promoter region of PR1 on infection with the DC3000 strain, suggesting that an epigenetically regulated PR1 expression is involved in the plant defence. Our results suggest that histone methylation in response to pathogen infection may be a critical component in the signalling and defence processes occurring between plants and microbes. © 2011 THE AUTHORS. MOLECULAR PLANT PATHOLOGY © 2011 BSPP AND BLACKWELL PUBLISHING LTD.

Eerste inschatting van vrijkomen van plastics als gevolg van slijtage van Mosselzaad-Invagsystemen (MZI's)

NARCIS (Netherlands)

Hartog, E.; Brink, van den A.M.; Kamermans, P.

2014-01-01

IMARES heeft onderzoek uitgevoerd naar het ontstaan en de aanwezigheid van microplastic zwerfvuil afkomstig van mosselzaad invangsystemen (hierna MZI’s genoemd). Deze studie is onderdeel van een opdracht van het ministerie van EL&I, om de ecologische effecten van opschaling van MZI’s in de

Pseudomonas - Fact Sheet

OpenAIRE

Public Health Agency

2012-01-01

Fact sheet on Pseudomonas, including:What is Pseudomonas?What infections does it cause?Who is susceptible to pseudomonas infection?How will I know if I have pseudomonas infection?How can Pseudomonas be prevented from spreading?How can I protect myself from Pseudomonas?How is Pseudomonas infection treated?

Virus-induced Gene Silencing-based Functional Analyses Revealed the Involvement of Several Putative Trehalose-6-Phosphate Synthase/Phosphatase Genes in Disease Resistance against Botrytis cinerea and Pseudomonas syringae pv. tomato DC3000 in Tomato

Directory of Open Access Journals (Sweden)

Huijuan Zhang

2016-08-01

Full Text Available Trehalose and its metabolism have been demonstrated to play important roles in control of plant growth, development and stress responses. However, direct genetic evidence supporting the functions of trehalose and its metabolism in defense response against pathogens is lacking. In the present study, genome-wide characterization of putative trehalose-related genes identified 11 SlTPSs for trehalose-6-phosphate synthase, 8 SlTPPs for trehalose-6-phosphate phosphatase and one SlTRE1 for trehalase in tomato genome. Nine SlTPSs, 4 SlTPPs and SlTRE1 were selected for functional analyses to explore their involvement in tomato disease resistance. Some selected SlTPSs, SlTPPs and SlTRE1 responded with distinct expression induction patterns to Botrytis cinerea and Pseudomonas syringae pv. tomato (Pst DC3000 as well as to defense signaling hormones (e.g. salicylic acid, jasmonic acid and a precursor of ethylene. Virus-induced gene silencing-mediated silencing of SlTPS3, SlTPS4 or SlTPS7 led to deregulation of ROS accumulation and attenuated the expression of defense-related genes upon pathogen infection and thus deteriorated the resistance against B. cinerea or Pst DC3000. By contrast, silencing of SlTPS5 or SlTPP2 led to an increased expression of the defense-related genes upon pathogen infection and conferred an increased resistance against Pst DC3000. Silencing of SlTPS3, SlTPS4, SlTPS5, SlTPS7 or SlTPP2 affected trehalose level in tomato plants with or without infection of B. cinerea or Pst DC3000. These results demonstrate that SlTPS3, SlTPS4, SlTPS5, SlTPS7 and SlTPP2 play roles in resistance against B. cinerea and Pst DC3000, implying the importance of trehalose and tis metabolism in regulation of defense response against pathogens in tomato.

Syringa oblata Lindl var. alba as a source of oleuropein and related compounds

NARCIS (Netherlands)

Nenadis, N.; Vervoort, J.J.M.; Boeren, J.A.; Tsimidou, M.Z.

2007-01-01

The leaf methanol extract of Syringa oblata Lindl var. alba was investigated as a source of oleuropein and related compounds. The extract had a high total phenol content and a radical scavenging activity similar to that of the respective extract from Olea europaea leaves. HPLC-DAD characterisation

Versterking van de loopbaanladder van leraren : wat kunnen we leren van Singapore?

NARCIS (Netherlands)

Elffers, L.

2015-01-01

In de Lerarenagenda 2013-2020 is een aantal doelstellingen geformuleerd ten aanzien van de bevordering van de loopbaan en professionele ontwikkeling van leraren. Enerzijds wordt ingezet op het stimuleren van professionalisering van leraren na hun initiële opleiding, anderzijds op het versterken van

NpPDR1, a Pleiotropic Drug Resistance-Type ATP-Binding Cassette Transporter from Nicotiana plumbaginifolia, Plays a Major Role in Plant Pathogen Defense1

Science.gov (United States)

Stukkens, Yvan; Bultreys, Alain; Grec, Sébastien; Trombik, Tomasz; Vanham, Delphine; Boutry, Marc

2005-01-01

Nicotiana plumbaginifolia NpPDR1, a plasma membrane pleiotropic drug resistance-type ATP-binding cassette transporter formerly named NpABC1, has been suggested to transport the diterpene sclareol, an antifungal compound. However, direct evidence for a role of pleiotropic drug resistance transporters in the plant defense is still lacking. In situ immunolocalization and histochemical analysis using the gusA reporter gene showed that NpPDR1 was constitutively expressed in the whole root, in the leaf glandular trichomes, and in the flower petals. However, NpPDR1 expression was induced in the whole leaf following infection with the fungus Botrytis cinerea, and the bacteria Pseudomonas syringae pv tabaci, Pseudomonas fluorescens, and Pseudomonas marginalis pv marginalis, which do not induce a hypersensitive response in N. plumbaginifolia, whereas a weaker response was observed using P. syringae pv syringae, which does induce a hypersensitive response. Induced NpPDR1 expression was more associated with the jasmonic acid than the salicylic acid signaling pathway. These data suggest that NpPDR1 is involved in both constitutive and jasmonic acid-dependent induced defense. Transgenic plants in which NpPDR1 expression was prevented by RNA interference showed increased sensitivity to sclareol and reduced resistance to B. cinerea. These data show that NpPDR1 is involved in pathogen resistance and thus demonstrate a new role for the ATP-binding cassette transporter family. PMID:16126865

NpPDR1, a pleiotropic drug resistance-type ATP-binding cassette transporter from Nicotiana plumbaginifolia, plays a major role in plant pathogen defense.

Science.gov (United States)

Stukkens, Yvan; Bultreys, Alain; Grec, Sébastien; Trombik, Tomasz; Vanham, Delphine; Boutry, Marc

2005-09-01

Nicotiana plumbaginifolia NpPDR1, a plasma membrane pleiotropic drug resistance-type ATP-binding cassette transporter formerly named NpABC1, has been suggested to transport the diterpene sclareol, an antifungal compound. However, direct evidence for a role of pleiotropic drug resistance transporters in the plant defense is still lacking. In situ immunolocalization and histochemical analysis using the gusA reporter gene showed that NpPDR1 was constitutively expressed in the whole root, in the leaf glandular trichomes, and in the flower petals. However, NpPDR1 expression was induced in the whole leaf following infection with the fungus Botrytis cinerea, and the bacteria Pseudomonas syringae pv tabaci, Pseudomonas fluorescens, and Pseudomonas marginalis pv marginalis, which do not induce a hypersensitive response in N. plumbaginifolia, whereas a weaker response was observed using P. syringae pv syringae, which does induce a hypersensitive response. Induced NpPDR1 expression was more associated with the jasmonic acid than the salicylic acid signaling pathway. These data suggest that NpPDR1 is involved in both constitutive and jasmonic acid-dependent induced defense. Transgenic plants in which NpPDR1 expression was prevented by RNA interference showed increased sensitivity to sclareol and reduced resistance to B. cinerea. These data show that NpPDR1 is involved in pathogen resistance and thus demonstrate a new role for the ATP-binding cassette transporter family.

Duurzame inzetbaarheid van ouderen: resultaten van de eerste twee metingen van STREAM

NARCIS (Netherlands)

Heuvel, S. van den; Ybema, J.F; Leijten, F.; Wind, A. de

2013-01-01

In deze notitie richten we ons op voorspellers van duurzame inzetbaarheid, waarbij we gebruik maken van de resultaten van de eerste twee metingen van STREAM en van een interviewstudie bij deelnemers aan STREAM. Meer specifiek gaan we na hoe personen met gezondheidsproblemen toch productief kunnen

characterisation of bacterial brown spot pathogen from dry bean

African Journals Online (AJOL)

Prof. Adipala Ekwamu

Biolog GN Microplates were used to assess carbon substrate utilisation. The SyrB gene was .... Positive reaction was observed as granular ... nutrient broth as positive control (Ignjatov et al.,. 2007). ..... nucleation-active Pseudomonas syringae.

Bepaling van de kwaliteit van reinigingsprocessen.

NARCIS (Netherlands)

Terpstra, P.M.J.

1993-01-01

Ingegaan wordt op de operationalisering van het begrip schoon voor verschillende toepassingen. Daarna worden twee recent ontwikkelde onderzoekmethoden gepresenteerd voor de meting van respectievelijk het reinigingseffect van textiel reinigen en het reinigen van harde vloeroppervlakken en enkele met

Verbeteren van functionele fitheid van brandweermensen

NARCIS (Netherlands)

van Orden, Claudia Y.D.

Posterpresentatie over IAG4-project 'Functional Fitness Monitor', een methodiek voor het verbeteren van functionele fitheid van brandweermensen door een combinatie van meten, presenteren van feedback en coaching. Gepresenteerd op Symposium Healthy Work: Good for Business, gehouden op 29 april 2016

Dynamics of sugar content in vegetative organs of Syringa Genus representatives introduced into Steppe Zone

Directory of Open Access Journals (Sweden)

L. G. Dolgova

2005-12-01

Full Text Available Quantitative and qualitative contents of sugars in phases of growth and development in overground organs of species of Syringa L. genus were determined. It is shown a cryoprotective role of sugars in plants. Conclusions on resistance of plants under conditions of a steppe zone are made.

Reference: 466 [Arabidopsis Phenome Database[Archive

Lifescience Database Archive (English)

Full Text Available ernaria brassicicola concomitant with reduced expression of the jasmonate-regulated plant defensin PDF1.2 gene. Ectopic...n of the bacterial pathogen Pseudomonas syringae, although the ectopic expression of WRKY33 results in enhan

Gama de hospedeiros e reação de genótipos de tomateiro a Pseudomonas cichorii Host range and genotypes reaction to Pseudomonas cichorii

Directory of Open Access Journals (Sweden)

Tadeu Antônio Fernandes da Silva Júnior

2009-06-01

Full Text Available Em 2005, foi constatada em dois campos comerciais de tomate no Estado de São Paulo, a ocorrência da queima bacteriana, causada por Pseudomonas cichorii. Em vista disso, foram desenvolvidos estudos visando a determinação da gama de hospedeiros de isolados de Pseudomonas cichorii (IBSBF 2309 e IBSBF 2323, obtidos de tomateiro, provenientes de campos comerciais localizados nos municípios de Bragança Paulista e Mogi Guaçú, SP. Plantas de abobrinha, alface, beldroega, berinjela, beterraba, cenoura, couvebrócolo, datura, fumo, girassol, jiló, melão, pepino, petúnia, pimentão, rabanete, repolho, rúcula, salsa e tomateiro foram inoculadas por pulverização, separadamente, com os dois isolados de P. cichorii de tomateiro e um isolado de girassol (GIR-1. Os isolados IBSBF 2309 e IBSBF 2323 foram patogênicos à beldroega, datura, girassol, pimentão e tomate; GIR-1 foi patogênico apenas à beldroega, datura e girassol, não sendo patogênico ao pimentão e ao tomateiro. No Brasil não se conhecem fontes de resistência dentro do gênero Lycopersicon ou a reação de cultivares de tomateiros a esta bactéria. Vinte e oito genótipos de tomateiro provenientes do Banco de Germoplasma da empresa Sakata Seed Sudamerica Ltda., foram avaliados quanto a reação aos isolados IBSBF 2309 e IBSBF 2323 de P. cichorii, pelo método de inoculação nas folhas. Os maiores níveis de resistência foram observados em AF 11768, AF 2521, AF 11766, AF 11772, AF 229, AF 5719-1 e AF 8162. O genótipo AF 5719-1, que possui o gene Pto, que confere resistência a P. syringae pv. tomato, apresentou um bom nível de resistência a P. cichorii. A identificação de genótipos que apresentem bons níveis de resistência a este patógeno é importante para utilização em programas de melhoramento genético do tomateiro, visando a incorporação de genes de resistência a P. cichorii.The occurrence of the bacterial blight, caused by Pseudomonas cichorii, was observed

Novel experimental Pseudomonas aeruginosa lung infection model mimicking long-term host-pathogen interactions in cystic fibrosis

DEFF Research Database (Denmark)

Moser, Claus; van Gennip, Maria; Bjarnsholt, Thomas

2009-01-01

Moser C, van Gennip M, Bjarnsholt T, Jensen PO, Lee B, Hougen HP, Calum H, Ciofu O, Givskov M, Molin S, Hoiby N. Novel experimental Pseudomonas aeruginosa lung infection model mimicking long-term host-pathogen interactions in cystic fibrosis. APMIS 2009; 117: 95-107. The dominant cause of premature...... death in patients suffering from cystic fibrosis (CF) is chronic lung infection with Pseudomonas aeruginosa. The chronic lung infection often lasts for decades with just one clone. However, as a result of inflammation, antibiotic treatment and different niches in the lungs, the clone undergoes...... and 2003) of the chronic lung infection of one CF patient using the seaweed alginate embedment model. The results showed that the non-mucoid clones reduced their virulence over time, resulting in faster clearing of the bacteria from the lungs, improved pathology and reduced pulmonary production...

Verdeling van oxytetraxycline (afkomstig van versleping) in diervoeders

NARCIS (Netherlands)

Stolker, A.A.M.; Zuidema, T.; Egmond, van H.J.; Jong, de J.; Haelermans, P.J.M.; Hooglugt, J.H.

2012-01-01

De laatste jaren is er een toenemende aandacht voor de mogelijke bijdrage van therapeutisch gebruik van antibiotica in de dierhouderij op de ontwikkeling van antimicrobiële resistentie. Een additionele bron van blootstelling van landbouwhuisdieren aan antibiotica is versleping via diervoeders. In

Expression analysis of the fpr (ferredoxin-NADP+ reductase) gene in Pseudomonas putida KT2440

International Nuclear Information System (INIS)

Lee, Yunho; Pena-Llopis, Samuel; Kang, Yoon-Suk; Shin, Hyeon-Dong; Demple, Bruce; Madsen, Eugene L.; Jeon, Che Ok; Park, Woojun

2006-01-01

The ferredoxin-NADP + reductase (fpr) participates in cellular defense against oxidative damage. The fpr expression in Pseudomonas putida KT2440 is induced by oxidative and osmotic stresses. FinR, a LysR-type transcriptional factor near the fpr gene in the P. putida KT2440 genome, is required for induction of the fpr under both conditions. We have shown that the fpr and finR gene products can counteract the effects of oxidative and osmotic stresses. Interestingly, FinR-independent expression occurs either during a long period of incubation with paraquat or with high concentrations of oxidative stress agent. This result indicates that there may be additional regulators present in the P. putida KT2440 genome. In contrast to in vivo expression kinetics of fpr from the plant pathogen, Pseudomonas syringae, the fpr gene from P. putida KT2440 exhibited unusually prolonged expression after oxidative stress. Transcriptional fusion and Northern blot analysis studies indicated that the FinR is negatively autoregulated. Expression of the fpr promoter was higher in minimal media than in rich media during exponential phase growth. Consistent with this result, the fpr and finR mutants had a long lag phase in minimal media in contrast to wild-type growth characteristics. Antioxidants such as ascorbate could increase the growth rate of all tested strains in minimal media. This result confirmed that P. putida KT2440 experienced more oxidative stress during exponential growth in minimal media than in rich media. Endogenous promoter activity of the fpr gene is much higher during exponential growth than during stationary growth. These findings demonstrate new relationships between fpr, finR, and the physiology of oxidative stress in P. putida KT2440

Cis- and trans-zeatin differentially modulate plant immunity

Czech Academy of Sciences Publication Activity Database

Grosskinsky, D. K.; Edelsbrunner, K.; Pfeifhofer, H.; van der Graaff, E.; Roitsch, Thomas

2013-01-01

Roč. 8, č. 7 (2013), "e24798.1"-"e24798.4" ISSN 1559-2324 Institutional support: RVO:67179843 Keywords : Pseudomonas syringae * cytokinin * phytohormone * plant defense * plant immunity * plant pathogen interaction * plant resistance * tobacco * zeatin Subject RIV: ED - Physiology

ORF Alignment: NC_004578 [GENIUS II[Archive

Lifescience Database Archive (English)

Full Text Available NC_004578 gi|28871348 >1dlwA 1 114 25 138 3e-25 ... ref|NP_793967.1| protozoan/cyanob...acterial globin family protein [Pseudomonas ... syringae pv. tomato str. DC3000] gb|AAO57662.1| ... protozoa

Selectie van Italiaanse werkwoordsvormen op basis van frequentieonderzoek

NARCIS (Netherlands)

Boer, M.G. de

2009-01-01

SAMENVATTING Dit artikel is een vroege recensie (mei 1972) van het LIF, de frequentielijst van IBM Italia uit 1971. De auteur concentreert zich op de verschillen met het project van Juilland, dat als uitgangspunt voor het LIF heeft gefungeerd. Op grond van de gegevens van het LIF is een basislijst

Coexistence between neighbours

DEFF Research Database (Denmark)

Shenge, K.C.; Mabagala, R.B.; Mortensen, C A Nieves Paulino

2008-01-01

Experiments were conducted under laboratory and screenhouse conditions to study the coexistence between Pseudomonas syringae pv. tomato and Xanthomonas campestris pv. vesicatoria, incitants of bacterial speck and bacterial spot diseases of tomato. Results of in vitro studies showed that when mixe...

Functional analysis of Arabidopsis immune-related MAPKs uncovers a role for MPK3 as negative regulator of inducible defences

KAUST Repository

Frei dit Frey, Nicolas; Garcia, Ana; Bigeard, Jean; Zaag, Rim; Bueso, Eduardo; Garmier, Marie; Pateyron, Sté phanie; de Tauzia-Moreau, Marie-Ludivine; Brunaud, Vé ronique; Balzergue, Sandrine; Colcombet, Jean; Aubourg, Sé bastien; Martin-Magniette, Marie-Laure; Hirt, Heribert

2014-01-01

-induced genes and we identify a negative role for MPK3 in regulating defence gene expression, flg22-induced salicylic acid accumulation and disease resistance to Pseudomonas syringae. Among the MAPK-dependent genes, 27% of flg22-upregulated genes and 76

’n Oorsig van die bepaling van die vroeë bakterisidiese aktiwiteit van verskeie antituberkulosemiddels

Directory of Open Access Journals (Sweden)

P. R. Donald

2003-06-01

Full Text Available Die vroeë bakterisidiese aktiwiteit (VBA van ’n antituberkulosemiddel is die daaglikse afname van M tuberculosis in log10 kolonievormende eenhede per ml sputum, tydens die eerste twee dae van behandeling met die middel. Dit weerspieël die vermoë van ’n middel om aktief metaboliserende organismes in tuberkulose-longholtes te dood. Dit is ’n relatief goedkoop metode om in ’n klein groep pasiënte die antituberkulose-aktiwiteit van ’n middel, binne maande, in vivo te evalueer. Hierdie artikel som ons ondervinding op tydens sewe gepubliseerde VBA-studies, en die bronne van variasie in die prosedure word identifiseer. Die pasiënte in hierdie studies was gemiddeld 33 jaar oud, met ’n gemiddelde gewig van 50 kg en 55% het ekstensiewe of massiewe longaantasting gehad. Die hoogste VBA-waardes (0,50-0,66 is gevind in pasiënte wat isoniasied ontvang het, en die laagste waardes (0,05 en 0,09 respektiewelik was gevind in pasiënte wat die aminoglikosiede amikasien en paromomisien, albei in doserings van 15 mg/kg liggaamsgewig, ontvang het. Die algehele variasie in die VBA van 248 pasiënte was 0,0312, en die variasie toegeskryf aan die proses van sputumproduksie en -versameling was 0,0223. Dit blyk dat die verskillende aspekte van sputumproduksie en -versameling, betrokke by die lewering van ’n verteenwoordigende sputummonster, ’n groter bydrae maak tot variasie tydens die prosedure as die laboratoriumaspekte van die tegniek. Die keuring van pasiënte vir insluiting in VBA-studies, en hulle vermoë om saam te werk om ’n verteenwoordigende sputummonster te produseer, is van deurslaggewende belang in die suksesvolle voltooiing van VBA-studies.

Chloroplast DNA haplotype samenstelling van eikenopstanden (categorie "van bekende origine") van de Rassenlijst van Bomen; een aanvullende methode voor identificatie van autochtoniteit

NARCIS (Netherlands)

Buiteveld, J.; Boerwinkel, M.C.; Bovenschen, J.; Kranenborg, K.G.; Vries, de S.M.G.

2005-01-01

Tegenwoordig kan autochtoon materiaal op de Rassenlijst van Bomen geplaatst worden in de categorie `van bekende origine¿ en heeft daardoor een `officiële¿ status. Identificatie van autochtone opstanden blijft echter nog een lastige zaak. Momenteel worden autochtone opstanden geïdentificeerd met de

Biologische effectiviteit van bespuitingen: effecten van druppelgrootte en waterkwaliteit

NARCIS (Netherlands)

Zande, van de J.C.; Schans, van der D.A.; Koster, A.T.J.

2004-01-01

Deze rapportage beschrijft de invloed van watervolume, druppelgrootte en kwaliteit van het tankmengsel op de biologische effectiviteit van bespuitingen. Onder kwaliteit van het tankmengsel wordt in dit verband verstaan: temperatuur, hardheid, pH en zoutgehalte (chloor en ijzerzouten) van de

Verslag van de voorstudie: Paddenstoelen bedrijf van de toekomst

NARCIS (Netherlands)

Tuijl, van B.A.J.; Bos, A.P.; Sonnenberg, A.S.M.

2013-01-01

Het rapport ‘Paddenstoelenbedrijf van de toekomst’ is het resultaat van een uitgebreid vooronderzoek en geeft de eerste aanzet tot het creëren van gemeenschappelijke visie van de sector op een betere toekomst voor paddenstoelenkwekerijen. Het rapport doet verslag van een reeks interviews en een

Comparative antimicrobial activity of clove and fennel essential oils ...

African Journals Online (AJOL)

Bactericidal activity of culinary spices was evaluated against five food spoilage bacteria namely: Pseudomonas syringae, Bacillus subtilis, Escherichia coli, Staphylococcus sp., and Aeromicrobium erythreum. Fennel oil was found fairly active against bacterial strains as compared to clove oil with highest antibacterial activity ...

Samenstelling van de vluchtige olie van Origanum vulgare L. ssp. vulgare gedurende de ontwikkeling van de plant

NARCIS (Netherlands)

Maarse, Henk

1971-01-01

INLEIDING EN DOEL VAN HET ONDERZOEK Vele onderzoekers hebben de laatste jaren de vorming van de verbindingen in vluchtige olien van planten bestudeerd door het bepalen van de verandering in de samenstelling van de vluchtige olie tijdens de groei van de plant. Lemli (68) wees als eerste op de

Onderzoek naar vermindering van de bijvangst van een boomkortuig

NARCIS (Netherlands)

Marlen, van B.; Ybema, M.S.; Duijn, van J.B.

2005-01-01

In het kader van EU-project RECOVERY werden vergelijkende visserij- en selectiviteitsproeven uitgevoerd in 2002 en 2003 aan boord van MS “Tridens” aan 12 m boomkortuigen. De resultaten van een negental vistuigproeven zijn hier gegeven, gericht op het bepalen van het effect van een grote mazen kap

Die Romeinse nastrewing van onsterflikheid deur middel van memoria

Directory of Open Access Journals (Sweden)

D. R. Fouché

1985-05-01

Full Text Available Benewens die omvangryke en nasionale manifestasies van die oorspronklike onsterflikheidsgedagte in die Romeinse gemeenskap, vind ons by die Romein op kleiner skaal in groepe of indiwidueel ’n strewe na onsterflikheid langs die weg van memoria. Soos aangetoon sal word, verskil die pogings van die verskillende groepe radikaal van mekaar, hoewel die strewe en einddoel dieselfde bly, naamlik om deur die daarstelling van memoria op die gebied van woord of daad onsterflikheid te bekom.

Het planetarium van Hartog van Laun

Directory of Open Access Journals (Sweden)

Hans Hooijmaaijers

2009-12-01

Full Text Available The instrument maker Hartog van Laun devised a special table for an orrery, a lunarium and a tellurium. Van Laun made these instruments for educational purposes, but what makes his planetariums so interesting is the great variety and accuracy of demonstrations one can perform with them. In this paper I will deal with Van Laun and his instrument makers business. I will outline the design of the planetarium and some of the firm’s other instruments. Furthermore I will demonstrate that the detailed description of the planetarium made by Professor Jan Hendrik van Swinden boosted the spread of the instrument.

‘n Kritiese bespreking van roskam se seining van apartheid as grondslag van die Suid-afrikaanse samelewing

Directory of Open Access Journals (Sweden)

N. van Loggerenberg

1963-03-01

Full Text Available Segregasie is al deur vele ondersoekers histories tot ’n tradisie uit die stigtingsjaar 1652 met die aankoms van Jan van Riebeeck herlei. Roskam sion dit egter as 'n beleid wat veel later aanvaar is. Hy sien dit as beleid wat bepaalde groepe van die bevolking as 'n politieke eenheid, kragtens ’n sosiale hiërargie, van mekaar wil afskei, isoleer. Dit is vir  hom duidelik dat die politieke eenheid van Ordinansie 50 van 1828 nooit werklikheid geword het nie, en die tradisie van blanke heerskappy pas vir liom as heleid beter in die huidige situasic as segregasie. Roskam is dan van oordeel dat ..white supremacy” daarom die juiste en omskrywende betekenis van segregasie is.

Detectie van ziektesymptomen met behulp van fluorescentiebeelden

NARCIS (Netherlands)

Loon, van P.C.C.

2004-01-01

Rapport over de positie van de biologische paddestoelenteelt op intersectoraal en (inter)-regionaal niveau. Het overzicht in tabel- en schemavorm van de stromen grondstoffen en producten verduidelijkt de intersectorale positie van de champignonteelt. Dit kan een aanzet zijn bij het signaleren en

Een revisie van de taxonomie van gifkikkers

NARCIS (Netherlands)

Poelman, E.H.

2007-01-01

Recent kwam het lang verwachte ruim tweehonderdvijftig pagina`s tellende manuscript uit met daarin een revisie van de taxonomie van gifkikkers. De auteurs onder leiding van Taran Grant stellen een nieuwe taxonomie voor, die de familie Dendrobatidae met haar tien algemener geaccepteerde genera

De toekomst van flex : een onderzoek van tno naar flexstrategieën van Nederlandse bedrijven

NARCIS (Netherlands)

Verbiest, S.E.; Goudswaard, A.; Wijk, E.B. van

2014-01-01

In 2020 zal het personeelsbestand van organisaties voor 30% uit flexkrachten bestaan. Op dit moment is dat 25%. Dit blijkt uit een onderzoek van TNO onder 900 ondernemingen in opdracht van de ABU (Algemene Bond Uitzendondernemingen). Het blijkt dat met name organisaties die al gebruikmaken van

De trek van kruiden van volgroeid wortelmateriaal : handleiding van A tot Z in beknopte vorm

NARCIS (Netherlands)

Wijk, van C.A.P.

2005-01-01

Deze teelthandleiding richt zich op de trek van vooral dragon, krulpeterselie, rucola en munt, uitgaande van wortelmateriaal dat in de vollegrond wordt geteeld. Deze forcering richt zich zowel op aanbod van kruiden in potjes als de meermalige oogst van het gesneden product in een kas of een

Numerieke simulatie van de blastbelasting op vlucht MH17 van Malaysia Airlines als gevolg van de detonatie van een gevechtslading (U)

NARCIS (Netherlands)

2015-01-01

De Onderzoeksraad voor Veiligheid (OVV) onderzoekt de crash van vlucht MH17 van Malaysia Airlines die plaatsvond op donderdag 17 juli 2014 in de regio Donetsk (Oekraïne). De OVV wil een duidelijk beeld geven van de oorzaak van de crash. Een mogelijke oorzaak is fatale schade aan het vliegtuig als

Microbial contaminants of cultured Hibiscus cannabinus and Telfaria ...

African Journals Online (AJOL)

Nine microbial contaminants comprising of five bacteria and four fungi species were isolated from Hibiscus cannabinus and Telfaria occidentalis cultured tissues. The rate of occurrence of bacteria isolates was higher than that of fungi. The bacterial isolates includes Pseudomonas syringae pv phaseolicoli, Bacillus ...

Catalytic Mechanism and Mode of Action of the Periplasmic Alginate Epimerase AlgG

NARCIS (Netherlands)

Wolfram, Francis; Kitova, Elena N.; Robinson, Howard; Walvoort, Marthe T. C.; Codee, Jeroen D. C.; Klassen, John S.; Howell, P. Lynne

2014-01-01

Background: The alginate epimerase AlgG converts mannuronate to its C5 epimer guluronate at the polymer level. Results: The structure of Pseudomonas syringae AlgG has been determined, and the protein has been functionally characterized. Conclusion: His(319) acts as the catalytic base, whereas

Dicty_cDB: Contig-U06475-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available hensi glutathione S-... 33 4.0 AY754335_1( AY754335 |pid:none) Anopheles stephensi ..... 33 4.0 AE016853_1995( AE016853 |pid:none) Pseudomonas syringae pv. tomato... 33 4.0 AY573189_1( AY573189 |pid:none) Anopheles step

Bacterial effector HopF2 interacts with AvrPto and suppresses Arabidopsis innate immunity at the plasma membrane

Science.gov (United States)

Plant pathogenic bacteria inject a cocktail of effector proteins into host plant cells to modulate the host immune response, thereby promoting pathogenicity. How or whether these effectors work cooperatively is largely unknown. The Pseudomonas syringae DC3000 effector HopF2 suppresses the host plan...

Probing Pseudomonas syringae host interactions using metatranscriptomics

Science.gov (United States)

Transcriptome analyses during the interaction of plants and pathogens can be used to provide insights into molecular mechanisms of plant resistance as well as the mechanisms used by bacteria to adapt to hosts and cause disease. We performed a dual in planta RNA-Seq experiment to profile RNA expressi...

Filosofiese tendense in die wordinggeskiedenis van ons verstaan van die fisiese natuur

Directory of Open Access Journals (Sweden)

D. F. M. Strauss

2006-09-01

Full Text Available Die ontstaan van ’n lang tradisie van natuurwetenskaplike denke is in antieke Griekeland te vind – die bakermat van die Westerse beskawing en die bron van geartikuleerde rasionele besinning. Die vroegste fases van die Griekse kultuur het reeds geboorte geskenk aan ’n teoretiese nadenke oor die heelal. Die Pythagoreërs is veral bekend vir hul klem op die verklaringskrag van getalsverhoudinge. In hul tese dat “alles getal is” het hulle egter slegs rasionale getalle (breuke erken en gevolglik uiteindelik vasgeloop in die ontdekking van irrasionale getalle wat tot die geometrisering van die Griekse wiskunde gelei het en tegelyk die bedding gevorm het van waaruit ’n magtige tradisie van ruimte-metafisika gegroei het wat die hele middeleeuse tydperk omspan het. Die vermeende statiese syn is in die mees ekstreme geval – die skool van Parmenides en die argumente van Zeno teen veelheid en beweging – tot in die uiteindelike antinomiese konsekwensies daarvan deurdink. Dit was egter eers die vroeg-moderne tyd – die voorgangers en nakomelinge van Galilei – wat naas getal en ruimte ’n waardering ontwikkel het vir die verklaringskrag van beweging (vergelyk die klassieke meganistiese wêreldbeeld van die heelal as ’n meganisme van stofdeeltjies in beweging. Maar ook hierdie meganistiese reduksie (waardeur alle fisiese verskynsels herlei is tot die beweging van al of niegelade massapunte sou uiteindelik misluk omdat dit nie van die onomkeerbaarheid van fisiese prosesse rekenskap kon gee nie. Gevolglik beliggaam eers die fisika van die 20ste eeu ’n erkenning van die deurslaggewend-stempelende rol van energie-werking (dus van die fisiese aspek in die aard van stoflike dinge en prosesse. Die artikel word afgesluit met ’n vlugtige verduideliking van die implikasies van die voorafgaande argumentasie vir ’n benadering van die misterie van die bestaan van materie.

Beoordeling van het gedrag van bestrijdingsmiddelen in de verzadigde zone van de bodem

NARCIS (Netherlands)

Linden AMA van der; Beek CGEM van; Boesten JJTI; Leistra M; Meinardi CR; Puijker LM; LBG

1994-01-01

In het MeerJarenPlan-Gewasbescherming van 1991 is de mogelijkheid gegeven om door middel van onderzoek in de verzadigde fase van de bodem aan te tonen dat bestrijdingsmiddelen, die kunnen uitspoelen naar de verzadigde zone, alsnog voor toelating in aanmerking kunnen komen als de

Onderzoek naar de effecten van snoezelen op het gedrag van demente verpleeghuisbewoners en de werkbeleving van verzorgenden.

NARCIS (Netherlands)

Weert, J. van; Peter, J.; Dulmen, S. van; Ribbe, M.; Bensing, J.

2004-01-01

Het effect van snoezelen in de 24-uurszorg op de stemming en het gedrag van demente ouderen is nooit eerder onderzocht. Ook is in geen van de eerdere studies het effect onderzocht van snoezelen op de werkbeleving van verzorgenden. Uit onderzoek is bekend dat in verpleeghuizen waar geen

Beoordeling van het gedrag van bestrijdingsmiddelen in de verzadigde zone van de bodem

NARCIS (Netherlands)

Linden, van der A.M.A.; Beek, van C.G.E.M.; Boesten, J.J.T.I.; Leistra, M.; Meinardi, C.R.; Puijker, L.M.

1999-01-01

In het MeerJarenPlan-Gewasbescherming van 1991 is de mogelijkheid gegeven om door middel van onderzoek in de verzadigde fase van de bodem aan te tonen dat bestrijdingsmiddelen, die kunnen uitspoelen naar de verzadigde zone, alsnog voor toelating in aanmerking kunnen komen als de omzettingssnelheid

Bepaling van de optredende temperaturen bij tunnelcompostering van geitenmest

NARCIS (Netherlands)

Melse, R.W.; Sauvage, de G.J.; Roest, H.I.J.

2010-01-01

Het doel van het project is om inzicht te krijgen in de composteerbaarheid van geitenmest en het hiermee samenhangende temperatuursverloop . Bepaald dient te worden welke temperaturen tijdens het composteren van geitenmest worden bereikt om op basis daarvan een inschatting te kunnen maken van de

Kleinschalige raffinage van bietenblad : eerste verkenning van de moglijkheden

NARCIS (Netherlands)

Wolf, de P.L.; Visser, de C.L.M.; Keijsers, E.R.P.; Meesters, K.P.H.; Heesakkers, J.W.M.; Aerts, M.

2013-01-01

Doelstelling van de eerste fase van het onderzoek was ‘het verkennen van kleinschalige keten(s) voor de raffinage van bietenblad’, met aandacht voor de technologische en economische haalbaarheid. Deze verkenning vormt de basis voor de volgende fase, waarin kansrijke opties verder worden uitgewerkt

Presence of the vancomycin resistance gene cluster vanC1, vanXYc, and vanT in Enterococcus casseliflavus.

Science.gov (United States)

Hölzel, Christina; Bauer, Johann; Stegherr, Eva-Maria; Schwaiger, Karin

2014-04-01

The three chromosomally located clustered genes vanC1, vanXYc, and vanT confer intrinsic resistance to vancomycin and are used for species identification of Enterococcus gallinarum. In this study, 28 strains belonging to the E. gallinarum/casseliflavus group isolated from cloacal swabs from laying hens were screened for the presence of vanC1. As confirmed by species-specific multiplex PCR, 11 vanC1-positive strains were identified as E. gallinarum. Surprisingly, one yellow pigmented strain, verified as E. casseliflavus by species-specific multiplex PCR, was also vanC1 positive; vanXYc and vanT were additionally detectable in this strain. To our knowledge, this is the first report of vanC1, vanXYc, and vanT in E. casseliflavus. The minimum inhibitory concentration of vancomycin was 4 mg/L. Real-time reverse transcription-PCR revealed that none of the clustered genes was expressed in this strain. Even if the genes seem not to be active, there is a certain risk that they will be transferred to other bacteria where they might be functionally expressed. Therefore, it may be advisable to expand the search for vanC1, vanXYc, and vanT from E. gallinarum to other (enterococcal) species. This study confirms that enterococci live up to their name as being reservoir bacteria and should therefore always be closely monitored.

Die gebruik van parallelplaatreologie vir die bepaling van die intrinsieke viskositeit van poli-etileentereftalaat

Directory of Open Access Journals (Sweden)

O. C. Vorster

2005-09-01

Full Text Available Die bepaling van die intrinsieke viskositeit van poli-etileentereftalaat word bemoeilik deur die feit dat daar tans slegs twee metodes in gebruik is. In die eerste metode word die bepaling deur middel van oplossingsviskometrie gedoen, maar die toksisiteit van die oplosmiddel, asook die tydperk wat dit neem om die bepaling te doen, is ’n probleem. Die tweede metode word beperk deur die kompleksiteit en beskikbaarheid van die apparatuur in Suid-Afrika. In hierdie studie word ’n alternatiewe metode, gebaseer op parallelplaatreologie, voorgestel wat albei hierdie probleme oorkom en die resultate sodoende verkry, word vergelyk met dié wat met bestaande metodes verkry is.

Turning into Ice

Science.gov (United States)

Pietsch, Renée B.; Hanlon, Regina; Bohland, Cynthia; Schmale, David G., III

2016-01-01

This article describes an interdisciplinary unit in which students explore biological "ice nucleation"--by particles that cause water to freeze at temperatures above -38°C--through the lens of the microbial ice nucleator "Pseudomonas syringae." Such This activity, which aligns with the "Next Generation Science…

Die identifisering van maatstawwe vir die navorsingsprestasie van akademici

Directory of Open Access Journals (Sweden)

H. A. Labuschagne

1990-06-01

Full Text Available Identification of criteria for academic research performance. At South African universities, the achievement of objectives is usually measured in terms of so-called "process criteria" (e.g. pass rates, instead of performance criteria which reflect the quality of academic personnel. Stimulated by the need to identify valid indices of research performance, as a component of academic performance, this study investigated the dimensionality of several criteria, identified from empirical and literature studies. It was found that various valid criteria could be represented by six constructs, viz.: the stature of the researcher as scientist; scientific contributions; enhancement of own profession; community development; participation in research projects; and giving advice to persons or institutions outside the university. Opsomming By Suid-Afrikaanse universiteite word doelwitbereiking gewoonlik aan die hand van sogenaamde "prosesmaat-stawwe" (bv. slaagsyfers in plaas van prestasiemaatstawwe wat die gehalte van akademiese personeel weerspieel, gemeet. Na aanleiding van 'n behoefte aan die identifisering van geldige rigtingwysers vir navorsingsprestasie as 'n komponent van akademiese prestasie, is daar ondersoek ingestel na die dimensionaliteit van verskillende maatstawwe wat vooraf deur middel van empiriese- en literatuurstudies geidentifiseer is. Daar is gevind dat verskeie geldige maatstawwe deur ses konstrukte verteenwoordig word, te wete: die statuur van die navorser as wetenskaplike, wetenskaplike bydraes, uitbouing van eie professie, gemeenskapsontwikkeling, deelname aan navorsingsprojekte en advieslewering aan persone of instellings buite die Universiteit.

Genomic analysis of the Kiwifruit pathogen Pseudomonas syringae pv. actinidiae provides insight into the origins of an emergent plant disease.

Directory of Open Access Journals (Sweden)

Honour C McCann

Full Text Available The origins of crop diseases are linked to domestication of plants. Most crops were domesticated centuries--even millennia--ago, thus limiting opportunity to understand the concomitant emergence of disease. Kiwifruit (Actinidia spp. is an exception: domestication began in the 1930s with outbreaks of canker disease caused by P. syringae pv. actinidiae (Psa first recorded in the 1980s. Based on SNP analyses of two circularized and 34 draft genomes, we show that Psa is comprised of distinct clades exhibiting negligible within-clade diversity, consistent with disease arising by independent samplings from a source population. Three clades correspond to their geographical source of isolation; a fourth, encompassing the Psa-V lineage responsible for the 2008 outbreak, is now globally distributed. Psa has an overall clonal population structure, however, genomes carry a marked signature of within-pathovar recombination. SNP analysis of Psa-V reveals hundreds of polymorphisms; however, most reside within PPHGI-1-like conjugative elements whose evolution is unlinked to the core genome. Removal of SNPs due to recombination yields an uninformative (star-like phylogeny consistent with diversification of Psa-V from a single clone within the last ten years. Growth assays provide evidence of cultivar specificity, with rapid systemic movement of Psa-V in Actinidia chinensis. Genomic comparisons show a dynamic genome with evidence of positive selection on type III effectors and other candidate virulence genes. Each clade has highly varied complements of accessory genes encoding effectors and toxins with evidence of gain and loss via multiple genetic routes. Genes with orthologs in vascular pathogens were found exclusively within Psa-V. Our analyses capture a pathogen in the early stages of emergence from a predicted source population associated with wild Actinidia species. In addition to candidate genes as targets for resistance breeding programs, our findings

Invloed van minerale olie op de bestrijding van Phytophthora infestans in pootaardappelen

NARCIS (Netherlands)

Spits, H.G.; Bus, C.B.

2003-01-01

De invloed van toevoeging van olie aan een fungicide op de werking van het fungicide is afhankelijk van het gebruikte fungicide. Gezamenlijk spuiten van olie en Aviso DF, Curzate M en mogelijk ook Acrobat, verhoogt de curatieve werking van deze fungiciden. Gezamenlijk spuiten van olie en Aviso DF,

B. J. van der Merwe . Pentateugtradisies in die prediking van ...

African Journals Online (AJOL)

B. J. van der Merwe . Pentateugtradisies in die prediking van Deuterojesaja. Proefschrift ter verkrijging van de graad van Doctor in de Godgeleerdheid aan de Rijkuniversiteit te Groningen. Uitg. J. B. Wolters, Groningen, Djakarta. 1955. 280 bls.

n Oorsig van die huidige stand van navorsing oor die

African Journals Online (AJOL)

Test

7 Jun 2011 ... Die eerste maal wat dit as deel van die teks van 1 Johannes aangehaal word, is in die. 4de eeu in 'n Latynse teks, Liber Apologeticus (hf 4). Eers aan die einde van die 16de eeu is dit in 'n amptelike Katolieke uitgawe van die Vulgaat ingesluit. Die doel van die Johannesbriewe. Waarom is die Briewe ...

Detectie van Meloidogyne spp. in grondmonsters - een vergelijking van twee technieken

NARCIS (Netherlands)

Veenhuizen, P.T.M.; Schoemakers, N.; Vos, J.; Versteegen, F.; Landeweert, R.; Karssen, G.

2007-01-01

Hier volgen de samenvattingen van de bijeenkomst van 20 maart 2007 van de KNPV-werkgroep Meloidogyne. 1) Kwantitatieve multiplexdetectie van aaltjes; 2). Meloidogyne chitwoodi en M. fallax: vergelijking visuele beoordeling en Taqman-PCR aan pootaardappelen; 3) Detectie van Meloidogyne spp. in

Stroming en samenstelling van de sprengen en het grondwater van de Veluwe in 1996; een vergelijking met de toestand van 1986

NARCIS (Netherlands)

Meinardi CR; LBG

1999-01-01

Monsters water uit sprengen en grondwater van de Veluwe zijn onderzocht op concentraties van hoofdcomponenten en van microcomponenten (bepalingen door NITG). Onderzoek is gedaan ter bepaling van verblijftijden in de bodem van grondwater en van het water in sprengen. De intrekgebieden van de

A. VAN SELMS. LUKAS SE SEGSMAN VIR DIE GESKIEDENIS VAN ...

African Journals Online (AJOL)

Test

oordele aan die eerste drie hoofstukke van sy Evangelie, het Lukas onder „van ..... Simon te onderskei van Simon Petrus, hoef ons nie erns te maak nie. .... op hulle beurt vereenselwig met Mosa van Jos. .... i&) Lukas der Arzt. Leipzig, 1906.

Studies on the O-specific polysaccharide of the lipopolysaccharide from the Pseudomonas mediterranea strain C5P1rad1, a bacterium pathogenic of tomato and chrysanthemum.

Science.gov (United States)

Zdorovenko, Evelina L; Cimmino, Alessio; Marchi, Guido; Shashkov, Alexander S; Fiori, Mario; Knirel, Yuriy A; Evidente, Antonio

2017-08-07

An O-specific polysaccharide (OPS) was isolated from the lipopolysaccharide of Pseudomonas mediterranea strain C5P1rad1, the causal agents of tomato pith necrosis and Chrysanthemum stem rot, and studied by one- and two-dimensional 1 H and 13 C NMR spectroscopy. The following structure of the trisaccharide repeating unit of the OPS was established, which, to our knowledge, is unique among the known bacterial polysaccharide structures: →4)-β-d-ManpNAc3NAcA-(1 → 4)-β-d-ManpNAc3NAcA-(1 → 3)-α-d-QuipNAc4NAc-(1→ where QuiNAc4NAc and ManNAc3NAcA indicate 2,4-diacetamido-2,4,6-trideoxyglucose and 2,3-diacetamido-2,3-dideoxymannuronic acid, respectively. Pre-treatment of leaves with LPS or OPS preparations at 250 and 50 μg mL -1 did not inhibit development of a hypersensitivity reaction induced by P. mediterranea C5P1rad1 on tobacco, tomato and chrysanthemum plants. The same preparations at 250 μg mL -1 partially prevented elicitation of the hypersensitivity reaction by Pseudomonas syringae KVPT7RC on chrysanthemum but not tobacco and tomato. Copyright © 2017. Published by Elsevier Ltd.

The Arabidopsis PLAT Domain Protein1 Is Critically Involved in Abiotic Stress Tolerance

Czech Academy of Sciences Publication Activity Database

Tae Kyung, H.; van der Graaff, E.; Albacete, A.; Eom, S. H.; Grosskinsky, D. K.; Böhm, B.; Janschek, U.; Rim, Y.; Walid Wahid, A.; Kim, S.; Roitsch, Thomas

2014-01-01

Roč. 9, č. 11 (2014), e112946 E-ISSN 1932-6203 Institutional support: RVO:67179843 Keywords : abscisic-acid * endoplasmic-reticulum * salicylic-acid * transcription factors * gene-expression * pseudomonas-syringae * signal-transduction * plants response * cold stress * salt stress Subject RIV: EH - Ecology, Behaviour Impact factor: 3.234, year: 2014

Digitale incunabelen : Over het belang van het archiveren van websites

NARCIS (Netherlands)

Voerman, Gerrit; Keyzer, Andreas; den Hollander, Franciscus

'Het geheugen van Nederland verpulvert'. Zo luidde de noodkreet van ruim twintig grote bibliotheken in het voorjaar van 1998. In een advertentie in enkele landelijke dagbladen vroegen deze bibliotheken om honderden miljoenen guldens voor het restaureren, fotograferen en digitaliseren van boeken en

Digitale incunabelen : Over het belang van het archiveren van websites

NARCIS (Netherlands)

Voerman, Gerrit; Keyzer, Andreas; den Hollander, Franciscus

2000-01-01

'Het geheugen van Nederland verpulvert'. Zo luidde de noodkreet van ruim twintig grote bibliotheken in het voorjaar van 1998. In een advertentie in enkele landelijke dagbladen vroegen deze bibliotheken om honderden miljoenen guldens voor het restaureren, fotograferen en digitaliseren van boeken en

Inclusie door interprofessionele samenwerking. : Resultaten van de proeftuinen van PACT.

NARCIS (Netherlands)

Doornenbal, Jeannette; Fukkink, Ruben; van Yperen, Tom; Balledux, Mariëlle; Spoelstra, Jolanda; Verseveld, Marloes

2017-01-01

Deze rapportage gaat over de resultaten van de PACT-proeftuinen waaraan in opdracht van Het Kinderopvangfonds van 2015 tot 2017 is gewerkt. PACT-proeftuinen zijn innovatieve praktijken waarin door middel van interprofessionele samenwerking tussen de kinderopvang, het basisonderwijs en de zorg wordt

Die opleiding van bedryfsielkundiges aan die universiteit van Fort Hare

Directory of Open Access Journals (Sweden)

W. Botha

1977-11-01

Full Text Available Die Departement Bedryfsielkunde aan die Universiteit van Fort Hare is 'n relatiewe jong departement en het eers in 1965 tot stand gekom. Voor hierdie datum is Bedryfsielkunde as 'n kort kursus deur die departement van suiwer Sielkunde aangebied en een van die destydse dosente, Dr. W. Backer, het die inisiatief geneem om 'n selfstandige departement van Bedryfsielkunde in die Fakulteit van Ekonomiese Wetenskappe op die been te bring.

Het effect van creatief schrijven op het lezen van korte verhalen

NARCIS (Netherlands)

Janssen, T.; van den Bergh, H.

2010-01-01

Schrijven en lezen zijn complementaire vaardigheden, niet alleen bij referentiële teksten, maar ook bij fictionele. Janssen en Van den Bergh doen verslag van een onderzoek naar de invloed van creatief schrijven op het lezen van verhalen. Als leerlingen, voorafgaand aan het lezen van een verhaal, een

Databank van de lithografische opbouw en morfologische ontwikkeling van de uiterwaarden van de Midden-Waal

NARCIS (Netherlands)

Hebinck, K.A.

2008-01-01

In de uiterwaarden zijn de komende decennia veel ingrepen gepland. Een goede kennis van de sedimentatiedynamiek en morfologische ontwikkeling van de uiterwaarden is daarbij een vereiste. Daartoe is een digitale databank (op CD bij dit rapport) opgesteld van de opbouw en geomorfologische ontwikkeling

Fluorescentievingerafdruk van Aardappel, Melganzenvoet en Mais : Eerste resultaten van plantonderscheid met behulp van fluorescentie

NARCIS (Netherlands)

Groot, T.T.; Nieuwenhuizen, A.T.

2012-01-01

Als het spectrum van één “soort” (gewas) vergeleken wordt met de rest (onkruid) neemt het onderscheid van het “gewas” af tot 70%. Het lijkt dus nodig ook de spectra van alle soorten onkruid in het veld te kennen om een goed onderscheid mogelijk te maken. De doelstelling voor deze metingen is een

Proeven van tekstkritiek. Een onderzoek betreffende de tekstgeschiedenis van de Renout van Montalbaen en de Perceval

NARCIS (Netherlands)

Hogenhout-Mulder, Maaike Janna

1984-01-01

In dit proefschrift wordt een poging gedaan de tekstgeschiedenis te achterhalen van twee Middelnederlandse tekstfragmenten: een gedeelte uit de RENOUT VAN MONTALBAEN en een gedeelte uit de PERCEVAL. ... Zie: Twee tekstfragmenten als object van onderzoek

Invoering van algemene vaardigheden: mogelijkheden van een vakoverstijgende aanpak

NARCIS (Netherlands)

Leenders, F.J.

2003-01-01

Centrale vraag: Het onderzoek richtte zich op de implementatie van vakoverstijgend vaardighedenonderwijs in de Tweede Fase van het voortgezet onderwijs. Belangrijkste conclusies: De brochure bevat onder meer een beschrijving van vijf scholen waar op verschillende wijze vaardighedenonderwijs

Resultaten van het Rijkswaterstaat JAMP 2009 monitoringsprogramma van bot (Platichthys flesus L.). Biologische gegevens van bot en milieukritische stoffen in bot

OpenAIRE

Hoek-van Nieuwenhuizen, van, M.; Barneveld, van, E.

2010-01-01

De in dit rapport beschreven werkzaamheden zijn in 2009 door IMARES uitgevoerd op basis van een opdracht van Rijkswaterstaat in het kader van het Joint Assessment and Monitoring Program van de OSPARCOM. De opdracht hield in het verkrijgen van biologische gegevens van bot (visziekten). De benodigde monsters bot werden verzameld door IMARES. Tevens werd materiaal van bot verzameld voor chemisch onderzoek en geanalyseerd.

Resultaten van het Rijkswaterstaat JAMP 2008 monitoringsprogramma van bot (Platichthys flesus L.). Biologische gegevens van bot en milieukritische stoffen in bot

NARCIS (Netherlands)

Hoek-van Nieuwenhuizen, van M.; Barneveld, van E.

2009-01-01

De in dit rapport beschreven werkzaamheden zijn door Wageningen IMARES uitgevoerd op basis van een opdracht van Rijkswaterstaat in het kader van het Joint Assessment and Monitoring Program van de OSPARCOM. De opdracht hield in het verkrijgen van biologische gegevens van bot. De benodigde monsters

Afbouw van het Wsw-bestand: actualisatie op basis van Wsw-gegevens ultimo 2013

NARCIS (Netherlands)

Berden, C.; Tempelman, C.

2014-01-01

In opdracht van het ministerie van Sociale Zaken en Werkgelegenheid heeft SEO Economisch Onderzoek onderzoek gedaan naar de verdeling van het Participatiebudget over gemeenten. Een onderdeel van dit onderzoek vormde het voorspellen van de afbouw van het huidige zittend bestand in de Wsw op basis van

Resultaten van het Rijkswaterstaat JAMP 2009 monitoringsprogramma van bot (Platichthys flesus L.). Biologische gegevens van bot en milieukritische stoffen in bot

NARCIS (Netherlands)

Hoek-van Nieuwenhuizen, van M.; Barneveld, van E.

2010-01-01

De in dit rapport beschreven werkzaamheden zijn in 2009 door IMARES uitgevoerd op basis van een opdracht van Rijkswaterstaat in het kader van het Joint Assessment and Monitoring Program van de OSPARCOM. De opdracht hield in het verkrijgen van biologische gegevens van bot (visziekten). De benodigde

Die beskerming van biologiese diversiteit deur gebruik te maak van die gevoeligheidsvariasie van spesies vir toksiese stowwe

Directory of Open Access Journals (Sweden)

A. J. Reinecke

2003-09-01

Full Text Available Pogings om algemeen geldende standaarde of maatstawwe vir omgewingskwaliteit op te stel vir die beskerming van Suid-Afrika se ryk biodiversiteit word bemoeilik deur die feit dat spesies baie kan verskil  ten opsigte van hulle gevoeligheid vir toksiese stowwe. Daar kan dus nie sonder meer vanaf een spesie na ’n ander geëkstrapoleer word nie. Deur egter juis gebruik te maak van hierdie variasie in gevoeligheid van spesies, kan die assessering van die risiko wat besoedelingstowwe vir organismes inhou wel op ’n meer wetenskaplike grondslag bedryf word. Hierdie konsep gaan uit van die standpunt dat indien kwaliteitskriteriums opgestel word wat die sensitiefste spesies beskerm, alle ander spesies outomaties beskerm word. Hierdie bydrae fokus op die gebruik van sensitiwiteitsverspreidings van spesies as metode en kyk oorsigtelik en krities na die aard en toepassings van die ekstrapolasiemodelle wat op hierdie verspreidings gebaseer is. Die moontlike aanwending daarvan en die argumente ten gunste daarvan en daarteen word bespreek. Die gevolgtrekking word gemaak dat spesie-sensitiwiteitsverspreidings wel nuttige aanwending kan vind, maar dat  gegewens oor die gevoeligheid van plaaslike spesies  baie skaars is. Hoewel dit reeds bruikbaar is, kan die algemene aanwending daarvan  in Suid-Afrika aansienlik uitgebrei word indien meer navorsing gedoen word om betroubare toksisiteitsgegewens vir verskillende spesies in te win, sodat die model meer verfyn kan word. Daarvoor moet gestandaardiseerde toksisiteitstoetse vir plaaslike spesies eers ontwikkel word.

Gevolgen van hydrocephalus

NARCIS (Netherlands)

Tromp, Cornelis Nicolaas

1984-01-01

Hydrocephalus is een aandoening van het centrale zenuwstelsel die de clinicus vrij lang voor grote problemen ten aanzien van de behandeling heeft qesteld. Door de toepassing van de ventriculo-atriale shunttechniek zijn de behandelingsmogelijkheden van hydrocephalus sterk verbeterd. Deze studie

Overzicht van de onderzoekresultaten van kroketten, bitterballen en frikandellen van 1986

NARCIS (Netherlands)

Cazemier, G.; Veen, van der N.G.

1987-01-01

In 1986 werden in opdracht van de AID 54 monsters frikandellen en 237 monsters kroketten en bitterballen door het RIKILT onderzocht op de eisen, zoals die zijn vastgelegd in de Kwaliteitsverordening Kroketten, Bitterballen en Frika(n)dellen. In dit verslag zijn de analyseresultaten van deze monsters

ʼn Kritiese evaluering van wetgewing wat die gesondheid van ...

African Journals Online (AJOL)

User

gereguleer wat "basiese watervoorsiening" omskryf as "die voorgeskrewe minimum standaard van watervoorsieningsdienste wat nodig is vir die betroubare voorsiening van ʼn toereikende hoeveelheid en gehalte water aan huishoudings, met inbegrip van informele huishoudings, om lewe en persoonlike higiëne te steun".

Karakterisering van het Etimologiewoordeboek van Afrikaans (EWA

Directory of Open Access Journals (Sweden)

Fons Moerdijk

2011-10-01

Full Text Available

Samenvatting: Zesendertig jaar na Afrikaanse etimologieë van Boshoff en Nienaber verscheener in 2003 een nieuw etymologisch woordenboek van het Afrikaans: het Etimologiewoordeboek vanAfrikaans (EWA. Tussen die twee woordenboeken bestaat een wezenlijk verschil. Het werk vanBoshoff en Nienaber is vrijwel alleen toegankelijk voor specialisten en niet specifiek bedoeld vooreen breed publiek. EWA is juist allereerst bestemd voor de leek die zich interesseert voor de oorsprongen de geschiedenis van de eigen taal. Daarnaast biedt het ook de etymoloog en historischtaalkundige een hoop gegevens en inspiratie voor nader onderzoek. Als etymologisch woordenboekbezit EWA een aantal bijzondere, eigen kenmerken. De selectie van de woorden is bepaalddoor het beoogde gebruikerspubliek. Als gevolg daarvan bevat EWA verscheidene typen woordendie in traditionele etymologische woordenboeken doorgaans veronachtzaamd worden, zoals afleidingen,samenstellingen, neologismen en gemeenzame spreektaalwoorden. De artikelstructuurwordt gekenmerkt door een hoge graad van uniformiteit en consistentie. Het accent ligt op dezogenaamde etymologia proxima, de etymologie waarbij men één stap teruggaat en de meestdirecte herkomst van het woord biedt. Voorts is speciale aandacht besteed aan polysemie: nietalleen de herkomst van de dominante betekenis van een woord wordt gegeven, maar ook die vanzijn eventuele andere betekenis(sen. Benoemingsmotieven komen ook veelvuldig aan bod. In eeneventuele tweede druk zouden opvallende verschillen in vorm of betekenis altijd verklaard of inieder geval besproken moeten worden. Dat blijft nu nogal eens achterwege. Ook zou voorafgaandaan zo'n volgende editie meer onderzoek naar woordhistorisch materiaal uit primaire bronnenvoor met name de 17de–19de eeuw verricht moeten worden. Het zou mooi zijn als deze eersteuitgave van EWA de aanleiding tot een dergelijk onderzoek zou vormen.

Sleutelwoorden: BENOEMINGSMOTIEF, ETYMOLOGIA PROXIMA

Kwantificatie van de invloed van regen op de verkeerdoorstroming

NARCIS (Netherlands)

Calvert, S.C.; Van Stralen, W.; Molin, E.J.E.

2013-01-01

Kwantificatie van de invloed van regen op de verkeerdoorstroming Het is bekend dat het weer invloed heeft op het verkeer op snelwegen, en in het bijzonder filevorming. Op de eerste plaats wordt de wegcapaciteit tijdelijk beïnvloed door een verandering in rijgedrag van bestuurders. Ten tweede

Resultaten van het RWS-RIKZ JAMP 2005 monitoringsprogramma van bot (Platichthys flesus L.) : Biologische gegevens van bot en milieukritische stoofen in bot

NARCIS (Netherlands)

Kotterman, M.J.J.

2006-01-01

In opdracht van RWS-RIKZ werden door het RIVO werkzaamheden uitgevoerd in het kader van het Joint Assessment and Monitoring Program van de OSPARCOM. De opdracht hield in het verkrijgen van biologische gegevens van bot. De werkzaamheden bestonden uit het verzamelen van monsters bot waarvan

'Uytnemende Schilder van Antwerpen' : Joos van Cleve: atelier, productie en werkmethoden

NARCIS (Netherlands)

Leeflang, Micha

2007-01-01

Joos van Cleve (ca. 1480-1541) was een van de meest invloedrijke Antwerpse schilders in de eerste helft van dezestiende eeuw. Hij kreeg belangrijke opdrachten voor portretten en altaarstukken van onder anderen de Franse koning Frans I. Micha Leeflang onderzocht met name de materieel-technische

Arabidopsis seedling flood-inoculation technique: a rapid and reliable assay for studying plant-bacterial interactions

Directory of Open Access Journals (Sweden)

Uppalapati Srinivasa R

2011-10-01

Full Text Available Abstract Background The Arabidopsis thaliana-Pseudomonas syringae model pathosystem is one of the most widely used systems to understand the mechanisms of microbial pathogenesis and plant innate immunity. Several inoculation methods have been used to study plant-pathogen interactions in this model system. However, none of the methods reported to date are similar to those occurring in nature and amicable to large-scale mutant screens. Results In this study, we developed a rapid and reliable seedling flood-inoculation method based on young Arabidopsis seedlings grown on MS medium. This method has several advantages over conventional soil-grown plant inoculation assays, including a shorter growth and incubation period, ease of inoculation and handling, uniform infection and disease development, requires less growth chamber space and is suitable for high-throughput screens. In this study we demonstrated the efficacy of the Arabidopsis seedling assay to study 1 the virulence factors of P. syringae pv. tomato DC3000, including type III protein secretion system (TTSS and phytotoxin coronatine (COR; 2 the effector-triggered immunity; and 3 Arabidopsis mutants affected in salicylic acid (SA- and pathogen-associated molecular pattern (PAMPs-mediated pathways. Furthermore, we applied this technique to study nonhost resistance (NHR responses in Arabidopsis using nonhost pathogens, such as P. syringae pv. tabaci, pv. glycinea and pv. tomato T1, and confirmed the functional role of FLAGELLIN-SENSING 2 (FLS2 in NHR. Conclusions The Arabidopsis seedling flood-inoculation assay provides a rapid, efficient and economical method for studying Arabidopsis-Pseudomonas interactions with minimal growth chamber space and time. This assay could also provide an excellent system for investigating the virulence mechanisms of P. syringae. Using this method, we demonstrated that FLS2 plays a critical role in conferring NHR against nonhost pathovars of P. syringae, but not to

An altered Pseudomonas diversity is recovered from soil by using nutrient-poor Pseudomonas-selective soil extract media

DEFF Research Database (Denmark)

Aagot, N.; Nybroe, O.; Nielsen, P.

2001-01-01

We designed five Pseudomonas-selective soil extract NAA media containing the selective properties of trimethoprim and sodium lauroyl sarcosine and 0 to 100% of the amount of Casamino Acids used in the classical Pseudomonas-selective Gould's S1 medium. All of the isolates were confirmed to be Pseu......We designed five Pseudomonas-selective soil extract NAA media containing the selective properties of trimethoprim and sodium lauroyl sarcosine and 0 to 100% of the amount of Casamino Acids used in the classical Pseudomonas-selective Gould's S1 medium. All of the isolates were confirmed....... Several of these analyses showed that the amount of Casamino Acids significantly influenced the diversity of the recovered Pseudomonas isolates. Furthermore, the data suggested that specific Pseudomonas subpopulations were represented on the nutrient-poor media. The NAA 1:100 medium, containing ca. 15 mg...... of organic carbon per liter, consistently gave significantly higher Pseudomonas CFU counts than Gould's S1 when tested on four Danish soils. NAA 1:100 may, therefore, be a better medium than Gould's S1 for enumeration and isolation of Pseudomonas from the low-nutrient soil environment....

Resultaten van het RWS-RIKZ JAMP 2006 monitoringsprogramma van bot (Platichthys flesus L.). Biologische gegevens van bot en milieukritische stoffen in bot

OpenAIRE

Kotterman, M.J.J.; Barneveld, van, E.

2007-01-01

De in dit rapport beschreven werkzaamheden werden door IMARES uitgevoerd op basis van een opdracht van Rijkswaterstaat- Rijksinstituut voor Kust en Zee (RIKZ) in het kader van het Joint Assessment and Monitoring Program van de OSPARCOM. De opdracht hield in het verkrijgen van biologische gegevens van bot. De benodigde monsters bot werden verzameld door IMARES. Tevens werd materiaal van bot verzameld voor chemisch onderzoek en geanalyseerd.

Toepassing van de basisvrachtbenadering op fosfaat van compost; advies

NARCIS (Netherlands)

Ehlert, P.A.I.

2005-01-01

Bij het vormgeven van het stelsel van gebruiksnormen is een maatschappelijke discussie ontstaan over de aanvoer van fosfaat met grond in compost en zwarte grond. Deze deskstudie gaat in op vragen die hierbij gesteld zijn. Het aandeel grond in compost en zwarte grond en de hoeveelheid fosfaat daarin

"Die beiteltjie" van N.P. van Wyk Louw en

African Journals Online (AJOL)

Tom

belangrike kenmerk van die postmodernisme is, wil ek dit nie tot abso- lute kenmerk verhef nie. Een van die .... oorgang vanaf 'n epistemologiese ingesteldheid tot 'n ontologiese ingesteldheid demonstreer en ..... the neglected and a whole range of phenomena which have been denied a history. Die formulering van die ...

Invioed van de zuurtegraad van varkensurine op de ammoniakemissie

NARCIS (Netherlands)

Eizing, A.; Aarnink, A.J.A.

1996-01-01

Dit rapport beschrijft het effect van een lagere urine-pH op de ammoniakemissie in een varkensstal. Het onderzoek is uitgevoerd in een modelopstelling met de zogenaamde stalsimulator, waarbij de invloed van de urine-pH op de ammoniakemissie werd onderzocht. Hiervoor werd de urine van vleesvarkens op

Expression of the Arabidopsis high-affinity hexose transporter STP13 correlates with programmed cell death

DEFF Research Database (Denmark)

Nørholm, Morten Helge Hauberg; Nour-Eldin, Hussam H; Brodersen, Peter

2006-01-01

GFP expression only in the vascular tissue in emerging petals under non-stressed conditions. Quantitative PCR and the pSTP13-GFP plants show induction of STP13 in programmed cell death (PCD) obtained by treatments with the fungal toxin fumonisin B1 and the pathogen Pseudomonas syringae. A role for STP...

Bacterial canker on kiwifruit in Italy: anatomical changes in the wood and in the primary infection sites.

Science.gov (United States)

Renzi, Marsilio; Copini, Paul; Taddei, Anna R; Rossetti, Antonio; Gallipoli, Lorenzo; Mazzaglia, Angelo; Balestra, Giorgio M

2012-09-01

The bacterial canker of kiwifruit caused by Pseudomonas syringae pv. actinidiae is a severe threat to kiwifruit production worldwide. Many aspects of P. syringae pv. actinidiae biology and epidemiology still require in-depth investigation. The infection by and spread of P. syringae pv. actinidiae in xylem and phloem was investigated by carrying out artificial inoculation experiments with histological and dendrochronological analyses of naturally diseased plants in Italy. We found that the bacterium can infect host plants by entering natural openings and lesions. In naturally infected kiwifruit plants, P. syringae pv. actinidiae is present in the lenticels as well as in the dead phloem tissue beneath the lenticels, surrounded by a lesion in the periderm which appears to indicate the importance of lenticels to kiwifruit infection. Biofilm formation was observed outside and inside plants. In cases of advanced stages of P. syringae pv. actinidiae infection, neuroses of the phloem occur, which are followed by cambial dieback and most likely by infection of the xylem. Anatomical changes in wood such as reduced ring width, a drastic reduction in vessel size, and the presence of tyloses were observed within several infected sites. In the field, these changes occur only a year after the first leaf symptoms are observed suggesting a significant time lapse between primary and secondary symptoms. It was possible to study the temporal development of P. syringae pv. actinidiae-induced cambial dieback by applying dendrochronology methods which revealed that cambial dieback occurs only during the growing season.

Ontwerp van een interventie om de groenteconsumptie van jongeren te verhogen

NARCIS (Netherlands)

Gilissen, L.J.W.J.; Meer, van der I.M.; Reinders, M.J.; Sluis, van der A.A.; Woltering, E.J.

2011-01-01

In dit rapport zullen verschillende mogelijke strategieën besproken worden die ingezet kunnen worden om de consumptie van groenten door jongeren te verhogen. De centrale vragen van dit onderzoek zijn: 1) Hoe kunnen groenten in het eetpatroon van jongeren een vaste plek van voldoende omvang krijgen?

Pseudomonas helleri sp. nov. and Pseudomonas weihenstephanensis sp. nov., isolated from raw cow's milk.

Science.gov (United States)

von Neubeck, M; Huptas, C; Glück, C; Krewinkel, M; Stoeckel, M; Stressler, T; Fischer, L; Hinrichs, J; Scherer, S; Wenning, M

2016-03-01

Analysis of the microbiota of raw cow's milk and semi-finished milk products yielded seven isolates assigned to the genus Pseudomonas that formed two individual groups in a phylogenetic analysis based on partial rpoD and 16S rRNA gene sequences. The two groups could be differentiated from each other and also from their closest relatives as well as from the type species Pseudomonas aeruginosa by phenotypic and chemotaxonomic characterization and average nucleotide identity (ANIb) values calculated from draft genome assemblies. ANIb values within the groups were higher than 97.3 %, whereas similarity values to the closest relatives were 85 % or less. The major cellular lipids of strains WS4917T and WS4993T were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol; the major quinone was Q-9 in both strains, with small amounts of Q-8 in strain WS4917T. The DNA G+C contents of strains WS4917T and WS4993T were 58.08 and 57.30 mol%, respectively. Based on these data, strains WS4917T, WS4995 ( = DSM 29141 = LMG 28434), WS4999, WS5001 and WS5002 should be considered as representatives of a novel species of the genus Pseudomonas, for which the name Pseudomonas helleri sp. nov. is proposed. The type strain of Pseudomonas helleri is strain WS4917T ( = DSM 29165T = LMG 28433T). Strains WS4993T and WS4994 ( = DSM 29140 = LMG 28438) should be recognized as representing a second novel species of the genus Pseudomonas, for which the name Pseudomonas weihenstephanensis sp. nov. is proposed. The type strain of Pseudomonas weihenstephanensis is strain WS4993T ( = DSM 29166T = LMG 28437T).

Isolation and Identification of Endophytic Bacteria with Plant Growth Promoting Activity and Biocontrol Potential from Wild Pistachio Trees.

Science.gov (United States)

Etminani, Faegheh; Harighi, Behrouz

2018-06-01

In this study, samples were collected from the leaves and stems of healthy wild Pistachio trees ( Pistacia atlantica L.) from various locations of Baneh and Marivan regions, Iran. In total, 61 endophytic bacteria were isolated and grouped according to phenotypic properties. Ten selected isolates from each group were further identified by partial sequencing of the 16S rRNA gene. Based on the results, isolates were identified as bacteria belonging to Pseudomonas , Stenotrophomonas , Bacillus , Pantoea and Serratia genus. The ability of these isolates was evaluated to phytohormone production such as auxin and gibberellin, siderophore production, phosphate solubilization, atmospheric nitrogen fixation, protease and hydrogen cyanide production. All strains were able to produce the plant growth hormone auxin and gibberellin in different amounts. The majority of strains were able to solubilize phosphate. The results of atmospheric nitrogen fixation ability, protease and siderophore production were varied among strains. Only Ba66 could produce a low amount of hydrogen cyanide. The results of biocontrol assay showed that Pb78 and Sp15 strains had the highest and lowest inhibition effects on bacterial plant pathogens, Pseudomonas syringae pv. syringae Pss20 and Pseudomonas tolaasii Pt18 under in vitro condition. Pb3, Pb24 and Pb71 strains significantly promote root formation on carrot slices. To our knowledge this is the first report of the isolation of endophytic bacterial strains belonging to Pantoea , Bacillus , Pseudomonas , Serratia and Stenotrophomonas genus from wild pistachio trees with plant growth promoting potential and biocontrol activity.

Reductie van het kiemgetal van bacteriën op champignons : literatuuroverzicht

NARCIS (Netherlands)

Baars, J.J.P.

2006-01-01

Dit rapport bevat een literatuurstudie waarin een overzicht wordt gegeven van de beschikbare literatuur m.b.t. hoogte van het kiemgetal van bacteriën op champignons en de grondstoffen voor de champignonteelt, aanwezigheid van pathogene bacteriën op champignons die in de retail worden aangeboden en

Het handwerk van de theorie in de praktijk van het Sociaal Werk

Directory of Open Access Journals (Sweden)

Hans Oostrik

2010-06-01

Sociaal werk is een narratieve praktijk. Vanuit een sociaal-constructivistische invalshoek, reflecteert de auteur in dit artikel op de vraag hoe vanuit deze narratieve praktijk tot theoretische handelingsmodellen kan worden gekomen. Drie elementen spelen daarbij een rol, welke door de auteur worden behandeld. Ten eerste zijn dat de vaardigheden van de professional, die bijdragen aan conceptualisering, zoals daar zijn: het signaleren van kwesties, het analyseren en vormen van begrippen en het ontwerpen van conceptuele modellen. Ten tweede kunnen theoretische modellen in de praktijk van het sociaal werk gebruikt worden als instrumenten om die praktijk als het ware te theoretiseren of reflectief te maken. De praktijk wordt met behulp van modellen zoals scenario’s en stappenplannen, verbeterd en verder ontwikkeld. Ten derde bestaat het handwerk van de theorie in het innemen van een theoretische houding of praktische verstandigheid waardoor sociaal werkers beter om kunnen gaan met de complexiteit van hun praktijk.

Effecten van wintergewassen op verliezen en benutting van stikstof bij de teelt van snijmaos; verslag van onderzoek op ROC Aver-Heino tussen voorjaar 1991 en najaar 1994

NARCIS (Netherlands)

Dijk, van W.; Schröder, J.J.; Holte, ten L.; Groot, de W.J.M.

1995-01-01

Tussen 1988 en 1994 is onderzoek verricht naar de effecten van wintergewassen (winterrogge en onderzaai van gras) op de verliezen en benutting van stikstof bij continuteelt van snijmaos op zandgrond. Gemiddeld over de gehele onderzoeksperiode nam zowel rogge als gras 30-40 kg/ha op in de

Comparative transcriptome proifling of two maize near-isogenic lines differing in the allelic state for bacterial brown spot disease resistance

Institute of Scientific and Technical Information of China (English)

WU Xiao-jun; Xu Li; ZHAO Pan-feng; LI Na; WU Lei; HE Yan; WANG Shou-cai

2015-01-01

The bacterial brown spot disease (BBS), caused primarily by Pseudomonas syringae pv. syringae van Hal (Pss), reduces plant vigor, yield and quality in maize. To reveal the nature of the defense mechanisms and identify genes involved in the effective host resistance, the dynamic changes of defense transcriptome triggered by the infection of Pss were investigated and compared between two maize near-isogenic lines (NILs). We found that Pss infection resulted in a sophisticated tran-scriptional reprogramming of several biological processes and the resistant NIL employed much faster defense responses than the susceptible NIL. Numerous genes encoding essential components of plant basal resistance would be able to be activated in the susceptible NIL, such as PEN1, PEN2, PEN3, and EDR1, however, in a basic manner, such resistance might not be sufifcient for suppressing Pss pathogenesis. In addition, the expressions of a large number of PTI-, ETI-, PR-, and WRKY-related genes were pronouncedly activated in the resistant NIL, suggesting that maize employ a multitude of defense pathways to defend Pss infection. Six R-gene homologs were identiifed to have signiifcantly higher expression levels in the resistant NIL at early time point, indicating that a robust surveil ance system (gene-to-gene model) might operate in maize during Pss attacks, and these homolog genes are likely to be potential candidate resistance genes involved in BBS disease resistance. Furthermore, a holistic group of novel pathogen-responsive genes were deifned, providing the repertoire of candidate genes for further functional characterization and identiifcation of their regulation patterns during pathogen infection.

Gebruik van TaqMan PCR voor het kwantificeren van Fusarium spp. en Microdochium nivale in gewassen en gewasresten van tarwe.

NARCIS (Netherlands)

Köhl, J.; Haas, de B.H.; Kastelein, P.; Burgers, S.L.G.E.; Waalwijk, C.

2005-01-01

Infecties van tarwe door toxigene Fusarium spp. kunnen leiden tot contaminatie van graan met diverse mycotoxines. Voorkoming van mycotoxinebesmetting is uit oogpunt van voedselveiligheid, diergezondheid, maar ook bedrijfseconomisch, vereist. Voor vier Fusariumsoorten is een kwantitatieve detectie

Van die Gasredakteur

African Journals Online (AJOL)

cherish and teach.'1. Die Fakulteit Geneeskunde van die Universiteit van die Oranje-Vrystaat het pragtig gegroei ge- durende die eerste 21 jaar van sy bestaan. Die entoesiasme, doelgerigtheid, harde werk en inisia- tiewe van 'n groot aantal persone was hiervoor verantwoordelik. 'If we see a bit more clearly than they, it is ...

De werking van de hydro- en acetylverbindingen van kinidine en kinine op het hart van Rana esculenta

NARCIS (Netherlands)

Sibie, Johan Dirk

1942-01-01

In hoofdstuk I werd een inleiding gegeven betreffende de geschiedenis van de kina en van het begin der kinacultuur op Java, de chemie der kinaälkaloïden en enkele aspecten der pharmacologische werking van de kinaderivaten. ... Zie: Samenvatting

Introductie van de Chevon : een zoektocht naar de afzet van geitenvlees

NARCIS (Netherlands)

Eleveld, I.; Louis Bolk,

2008-01-01

Het afmesten en afzetten van lammeren op een biologisch bedrijf is geen gemakkelijke weg. Aan de smaak van het vlees zal het niet liggen. De chevon, lammeren met een leeftijd van 5 tot 7 maand, geven vlees met karakter: een vleugje geit! De onbekendheid van het vlees vereist een zorgvuldige

De auteursrechtelijke aansprakelijkheid van intermediairs, het kabelpiratenarrest revisited in de tijd van Internet

NARCIS (Netherlands)

Dommering, E.J.; Verkade, D.W.F.; Visser, D.J.G.

1998-01-01

Het kabelpiratenarrest vestigde de auteursrechtelijke aansprakelijkheid van de kabelexploitant voor het verspreiden van gestolen films die clandestien na de uitzendingen van de reguliere omroepen werden uitgezonden met gebruikmaking van de centrale antenne-inrichting van KTA. Zouden wij de

Pseudomonas lactis sp. nov. and Pseudomonas paralactis sp. nov., isolated from bovine raw milk.

Science.gov (United States)

von Neubeck, Mario; Huptas, Christopher; Glück, Claudia; Krewinkel, Manuel; Stoeckel, Marina; Stressler, Timo; Fischer, Lutz; Hinrichs, Jörg; Scherer, Siegfried; Wenning, Mareike

2017-06-01

Five strains, designated WS 4672T, WS 4998, WS 4992T, WS 4997 and WS 5000, isolated from bovine raw milk formed two individual groups in a phylogenetic analysis. The most similar species on the basis of 16S rRNA gene sequences were Pseudomonas azotoformans IAM 1603T, Pseudomonas gessardii CIP 105469T and Pseudomonas libanensis CIP 105460T showing 99.7-99.6 % similarity. Using rpoD gene sequences Pseudomonas veronii LMG 17761T (93.3 %) was most closely related to strain WS 4672T and Pseudomonas libanensis CIP 105460T to strain WS 4992T (93.3 %). The five strains could be differentiated from their closest relatives and from each other by phenotypic and chemotaxonomic characterization and ANIb values calculated from draft genome assemblies. ANIb values of strains WS 4992T and WS4671T to the closest relatives are lower than 90 %. The major cellular polar lipids of both strains are phosphatidylethanolamine, phosphatidylglycerol, a phospholipid and diphosphatidylglycerol, and their major quinone is Q-9. The DNA G+C content of strains WS 4992T and WS 4672T were 60.0  and 59.7  mol%, respectively. Based on these genotypic and phenotypic traits two novel species of the genus Pseudomonas are proposed: Pseudomonas lactis sp. nov. [with type strain WS 4992T (=DSM 29167T=LMG 28435T) and the additional strains WS 4997 and WS 5000], and Pseudomonasparalactis sp. nov. [with type strain WS 4672T (=DSM 29164T=LMG 28439T) and additional strain WS 4998].

De mislukte missie van mr. Maarten van Naarden als luitenant-stadhouder van Stad en Lande 1541-1557

Directory of Open Access Journals (Sweden)

F. Postma

2005-01-01

Full Text Available Maarten van Naarden’s failed mission  as lieutenant-stadholder of the province of Groningen, 1541-1557In November 1557, Maarten van Naarden resigned from his post as lieutenant-stadholder of the province of Groningen and left the province after staying there for sixteen years. Van Naarden’s resignation was preceded by a number of conflicts with the Groningen town council and the States of the province. However, these conflicts were neither confined to Van Naarden nor the province of Groningen. They had also taken place  in other provinces in the Northeast of the Netherlands. What makes Van Naarden’s clash with the Groningen provincial authorities in the 1550s so important is that it clarifies the principles that were at stake. These principles were less apparent in the conflicts between the representatives of the central government in Friesland, Overijssel and Gelderland. It was a struggle in which Van Naarden tried, as his opponents rightly saw it, to introduce the ‘constitution’ of Utrecht in the town and county of Groningen. In Utrecht, which had been annexed by Charles V in 1528, the autonomy of the province had been reduced to next to nothing. The only authority still resting with the States was the surveillance of the provincial dikes and waterways. All their other areas of authority had been taken over by the provincial court of which Van Naarden had been president between 1537 and 1541. To avoid the same thing happening to them, Van Naarden was ordered to appear before the Groningen States assembly in January 1556. At this meeting, the weakness of his position became crystal clear. None of the members took his side. Because the government lacked the means to keep Van Naarden in office, his withdrawal from Groningen was inevitable. What we see behind the story of Van Naarden more clearly than in the conflicts in the neighbouring provinces is the outline of the absolute state that Van Naarden’s superiors had in mind for the

DIE ROL VAN DIE TAALWETENSKAP IN DIE ONTWIKKELING VAN ...

African Journals Online (AJOL)

aanslag op die sogenaamde "Intentional Fallacy", heelwat verder. n. Mens sou hier eintlik ook op die invloed van Lacan se toepassing van. De Sacs sure op Freud moet wys, en op Macherey se Theory of Literary. Production. Barthes is naamlik besig om repressie teen te werk, en die teks as produksieproses in stede van ...

'n Voordrag van Adrianus van Seims oor hermeneutiek | Boshoff ...

African Journals Online (AJOL)

A lecture on hermeneutics by Adrianus van Seims This article is the content of a lecture on hermeneutics given by A van Seims. After a few opening words on the introduction to the lecture and its content, the presentation is reproduced in its entirety. Van Seims considers that hermeneutics is concerned not only with ...

"Krakende kaken"; psychiatrische beschouwingen over het syndroom van het pijnlijke, slecht functionerende kaakgewricht (Arthrosis deformans van het kaakgewricht of het syndroom van Costen)

NARCIS (Netherlands)

Schuler, Jacques

1966-01-01

Naar aanleiding van klinische indrukken en mede op grond van literatuurgegevens werd een psychiatrisch onderzoek verricht naar het aandeel van psychogene factoren bij het tot stand komen van kaakgewrichtsklachten. Het klachtencomplex dat van stoornissen in de functie van het kaakgewricht het gevolg

Voedselverspilling, waarden van voedsel in de keten : de mogelijke rol van het groene onderwijs bij het oplossen van een maatschappelijke opgave

OpenAIRE

Waarts, Y.R.; Onwezen, M.C.; Wiersinga, R.C.; Eppink, M.M.; Thoden van Velzen, E.U.; Timmermans, A.J.M.

2009-01-01

Het doel van deze verkenning is om op basis van literatuur en interviews met belangrijkste stakeholders een visie te formuleren over de wijze waarop het groene onderwijs een bijdrage kan leveren aan het verminderen van voedselverliezen binnen alle schakels van de keten inclusief de consument, en aan de nuttige toepassing van reststromen.

die impak van metodologie op die verstaan van die nuwe testament

African Journals Online (AJOL)

voorbeeld eers een maal deur die bril van die vorm- en redaksiekritiek na die Evangelies gekyk het, dink jy vir altyd anders oor hulle tot- standkoming. Inderdaad, nuwe metodes lei tot nuwe perspektiewe! Dit is dan ook waar die fokus van hierdie artikel val: die impak van metodologie op die verstaan van die Nuwe ...

Effectieve bestrijding van varroa

NARCIS (Netherlands)

Cornelissen, B.; Blacquiere, T.; Steen, van der J.J.M.

2010-01-01

De varroa mijtziekte (Varroa destructor) is de belangrijkste bedreiging van de Europese honingbij. Wintersterfte van honingbijen is in de meeste gevallen toe te schrijven aan deze ziekte. Deze brochure van de WUR biedt informatie over de biologie van varroa, de effecten van varroa op honingbijen en

Prediking aan die hand van die metafoor van fiksieskryf

African Journals Online (AJOL)

p1243322

HTS 64(3) 2008 siening van die self en waarheid. In die pre-moderne paradigma kan die dominante metafoor verstaan word aan die hand van 'n spieël wat die lig uit 'n transendente oorsprong weerkaats, terwyl die moderne paradigma uitgedruk word met die metafoor van 'n lamp wat 'n eie, oorspronklike lig binne die self.

’n Etiek van liefde: Die etiese perspektiewe van die Heidelbergse Kategismus

Directory of Open Access Journals (Sweden)

Koos Vorster

2013-06-01

Full Text Available Hierdie artikel behandel die etiese perspektiewe van die Heidelbergse Kategismus – een van die prominente belydenisskrifte in die gereformeerde tradisie. Die etiese relevansie is ingebed in die konfessie se verklaring van die tien gebooie. Die artikel verduidelik dat die etiek van die Heidelbergse Kategismus ten diepste ’n karakteretiek is en dat dit gelowiges oproep tot ’n etiek van liefde. Hierdie liefde sluit in liefde vir die verbondsgemeenskap, die bediening van die Woord, die heiligheid van God en die waardigheid van mense, die gemeenskap van die gelowiges, gesag, die lewe, die huwelik, privaatbesit en arbeid asook waarheid en geregtigheid. As gevolg van die sinekdogeekarakter van die wet is hierdie etiek van liefde vandag baie relevant. This article deals with the ethical relevance of one of the prominent confessions in the reformed tradition, namely the Heidelberg Cathechism. The ethical relevance lies in the confession’s elucidation of the ten commandments and its application to moral conduct. The article explains that the ethics of the Heidelberg Catechism is essentially a virtue ethics calling for an ethics of love. This love should include love for the covenantal communion, ministry of the Word, the holiness of God and the dignity of people, the communion of the saints, authority, life, marriage, private property and labour, and truth and justice. Due to the synecdochical character of the ten commandments this ethics of love is highy relevant in the present times.

Optimaliseren van een biovergister

NARCIS (Netherlands)

van der Bij, Joost; Rademaker, Mark; Visser, Klaas; de Vries, Herman

2014-01-01

Dit rapport beschrijft onderzoek van conversie van biomassa in een Swill-gasser geplaatst bij het Van der Valk restaurant in Cuijk. De Swill-gasser is een biomassa vergister voor restaurant afval. Het onderzoek heeft zich gericht op het optimaliseren van de data acquisitie en op het bepalen van de

Kenmerkend van hierdie afdeling is die tema van ouderdom wat in ...

African Journals Online (AJOL)

8 Apr 2016 ... Kenmerkend van hierdie afdeling is die tema van ouderdom wat in menige van die stories voorkom. Hier is dit die onvermydelike aftakelingsproses van die liggaam (en verstand) wat 'n beduidende invloed op die skrywer het. In verhale soos “Wat 'n lieflike geraas”, “Die ou met die overall”, “Lofredes en ...

Bepaling van enkele neurotransmitters, monoaminen, en metabolieten, met behulp van Continuous Flowapparatuur

NARCIS (Netherlands)

Eigeman L; Schonewille F; Borst M; van der Laan JW

1986-01-01

Bij het onderzoek in de psychofarmacologie kan kennis van de effecten van stoffen op de omzettingssnelheid van neurotransmitters een belangrijk aspect zijn. Met de huidige psychofarmaca lijken vooral de klassieke neurotransmitters zoals de monoaminen, noradrenaline, dopamine en serotonine van

Kansen voor conflictbemiddeling : Verslag van een onderzoek naar de toepassingsmogelijkheden van conflictbemiddeling

NARCIS (Netherlands)

Geveke, Henk; Plant, Ernelies; Thieme, Marianneke; Verberk, Marielle

1998-01-01

In opdracht van het Platform ADR, een klankbordgroep en denktank op het gebied van alternatieve geschilbeslechting, is onderzoek verricht naar de toepasbaarheid van een specifieke vorm van Alternative Dispute Resolution (ADR): conflictbemiddeling (mediation). De onderzoeksopdracht was als volgt: het

De mislukte missie van mr. Maarten van Naarden als luitenant-stadhouder van Stad en Lande 1541-1557

NARCIS (Netherlands)

Postma, F.

2005-01-01

Maarten van Naarden’s failed mission as lieutenant-stadholder of the province of Groningen, 1541-1557 In November 1557, Maarten van Naarden resigned from his post as lieutenant-stadholder of the province of Groningen and left the province after staying there for sixteen years. Van Naarden’s

Ondersoek na ’n teoretiese onderskraging van boekkuns: Die toepassing van Bakhtin se dialogisme en heteroglossia op geselekteerde voorbeelde van kunstenaarsboeke

Directory of Open Access Journals (Sweden)

David Paton

2012-11-01

Full Text Available Onlangse navorsingsprojekte en konferensies oor boekkuns het gereageer op Johanna Drucker se oproep in 2005 dat noodsaaklike navorsingswerk gedoen moet word om ’n deegliker teoretiese basis vir die terrein van boekkunsproduksie te vestig. Die deelname van kunstenaars en ander praktisyns van boekkuns veroorsaak dat gesprekke en besprekings noodwendig en voorspelbaar neig na die praktyk en weg van die teorie. In die lig van die behoefte aan die bepaling van ’n toepaslike visie waarvolgens die kunsboek meer eksplisiet, ook teoreties, ondersoek kan word, ondersoek hierdie artikel Stéphane Mallarmé en Marcel Broodthaers se Un coup de dés publikasies, Buzz Spector se simplifiserende Marcel Broodthaers, Ulises Carrion se For fans and scholars alike, en Helen Douglas en Telfer Stokes se Real fiction. Hierdie spesifieke voorbeelde, en hulle onderlinge verbande en dialoog met mekaar, word ondersoek vanuit die perspektief van die Russiese filosoof en literêre teoretikus Mikhail Bakhtin se werk oor dialogisme en heteroglossia (‘ander-tongigheid’. Hierdie begrippe demonstreer die dialogiese, multivokale en veeltongige wisselwerking tussen en binne historiese werke as kultuuruitings. Deur die analise toon ek aan dat hierde begrippe toepaslike en funksionele raamwerke uitmaak vir die analise van spesifieke aspekte wat die teenwoordigheid van kunstenaarsboeke aankondig in die wêreld: selfbewustheid en omvattende diskoers wat wederkerend toepaslik is. Ek stel voor dat Bakthin se idees oor dialogisme en heteroglossie gebruik word as die teoretiese begronding van die kunstenaarsboek as ’n dinamiese visuele taal wat in ’n netwerk van ander tekste staan en deel is van die proses van die eindelose herbeskrywing van die wêreld.

Resultaten van het RWS-RIKZ JAMP 2006 monitoringsprogramma van bot (Platichthys flesus L.). Biologische gegevens van bot en milieukritische stoffen in bot

NARCIS (Netherlands)

Kotterman, M.J.J.; Barneveld, van E.

2007-01-01

De in dit rapport beschreven werkzaamheden werden door IMARES uitgevoerd op basis van een opdracht van Rijkswaterstaat- Rijksinstituut voor Kust en Zee (RIKZ) in het kader van het Joint Assessment and Monitoring Program van de OSPARCOM. De opdracht hield in het verkrijgen van biologische gegevens

Phosphorylcholine Phosphatase: A Peculiar Enzyme of Pseudomonas aeruginosa

Directory of Open Access Journals (Sweden)

Carlos Eduardo Domenech

2011-01-01

Full Text Available Pseudomonas aeruginosa synthesizes phosphorylcholine phosphatase (PchP when grown on choline, betaine, dimethylglycine or carnitine. In the presence of Mg2+ or Zn2+, PchP catalyzes the hydrolysis of p-nitrophenylphosphate (p-NPP or phosphorylcholine (Pcho. The regulation of pchP gene expression is under the control of GbdR and NtrC; dimethylglycine is likely the metabolite directly involved in the induction of PchP. Therefore, the regulation of choline metabolism and consequently PchP synthesis may reflect an adaptive response of P. aeruginosa to environmental conditions. Bioinformatic and biochemistry studies shown that PchP contains two sites for alkylammonium compounds (AACs: one in the catalytic site near the metal ion-phosphoester pocket, and another in an inhibitory site responsible for the binding of the alkylammonium moiety. Both sites could be close to each other and interact through the residues 42E, 43E and 82YYY84. Zn2+ is better activator than Mg2+ at pH 5.0 and it is more effective at alleviating the inhibition produced by the entry of Pcho or different AACs in the inhibitory site. We postulate that Zn2+ induces at pH 5.0 a conformational change in the active center that is communicated to the inhibitory site, producing a compact or closed structure. However, at pH 7.4, this effect is not observed because to the hydrolysis of the [Zn2+L2−1L20(H2O2] complex, which causes a change from octahedral to tetrahedral in the metal coordination geometry. This enzyme is also present in P. fluorescens, P. putida, P. syringae, and other organisms. We have recently crystallized PchP and solved its structure.

Voedingpraktyke en behoeftes van hulpbron-arm gemeenskappe deur die oë van laerskoolonderwysers

Directory of Open Access Journals (Sweden)

Ronel Ferreira

2013-02-01

Full Text Available In hierdie artikel bespreek ons die persepsies van onderwysers (n = 45 wat betref die voedingpraktyke van ’n steekproef laerskoolleerders en hul gesinne in ’n hulpbron-arm gemeenskap. Ons fokus spesifiek op die behoeftes, praktyke en verwagtings ten opsigte van die gebruik van voedsel, wat die produksie, keuse en voorbereiding van voedsel impliseer. Ons studie vorm die eerste deel van ’n groter institusionele navorsingprojek. Vir die doel van ons studie het ons deelnemende refleksie en aksie-gebaseerde werkwinkels gehou om data te genereer en tydens die interpretasie van bevindinge op interpretivisme staatgemaak. Hierdie studie beklemtoon die behoeftes van hulpbron-arm en werklose gemeenskapslede wat dikwels genoodsaak is om teen verlaagde pryse voedsel te koop waarvan die kwaliteit nie optimaal is nie. ’n Verskraalde ontbyt, middagete of aandete waarvan die keuse algemeen beperk is tot swart tee, pap en een of twee snye ou brood, bevestig die manifestasies van armoede in hulpbron-arm gemeenskappe. Maaltye is dikwels beperk tot groot hoeveelhede koolhidrate, min groente, ingelegde vis, pap met inkomazi en marog. Hoenderpote en afval vul soms die spyskaart aan. Onderwysers beklemtoon die feit dat gemeenskapslede tipies op skenkings van werkgewers, kerke en kruidenierswinkels staatmaak om hul voedselbegroting aan te vul. Onderwysers fokus verder op die behoeftes aan opleiding vir gemeenskapslede. Na hulle mening moet gemeenskappe ingelig word oor voedselproduksie, groentetuine, die wyses waarop die kwaliteit van grond bepaal kan word, besproeiing en die toepassing van volhoubare wisselbou. Die artikel word afgesluit met uitvoerbare en leersame wenke vir die opleiding van landelike gemeenskappe. Op grond van dié navorsingsbevindinge word ’n intervensieprogram tans ontwikkel, met die doel om dit in die onderskeie deelnemende skole te implementeer ter bevordering van gesonde voedselverwante gedrag en welsyn.

Beheersing van valse meeldauw in de akkerbouwmatige teelt van peterselie

NARCIS (Netherlands)

Mheen, van der H.J.C.J.; Lamers, J.G.

2009-01-01

In 2007 en 2008 heeft PPO-agv in opdracht van het Productwschap Akkerbouw onderzoek gedaan naar de beheersing van valse meeldauw in de akkerbouwmatige teelt van peterselie. Diverse fungicidentoepassingen zijn in staat om de peterselie (in meer of mindere mate) tegen valse meeldauw te beschermen.

A bacterial cysteine protease effector protein interferes with photosynthesis to suppress plant innate immune responses.

Science.gov (United States)

Rodríguez-Herva, José J; González-Melendi, Pablo; Cuartas-Lanza, Raquel; Antúnez-Lamas, María; Río-Alvarez, Isabel; Li, Ziduo; López-Torrejón, Gema; Díaz, Isabel; Del Pozo, Juan C; Chakravarthy, Suma; Collmer, Alan; Rodríguez-Palenzuela, Pablo; López-Solanilla, Emilia

2012-05-01

The bacterial pathogen Pseudomonas syringae pv tomato DC3000 suppresses plant innate immunity with effector proteins injected by a type III secretion system (T3SS). The cysteine protease effector HopN1, which reduces the ability of DC3000 to elicit programmed cell death in non-host tobacco, was found to also suppress the production of defence-associated reactive oxygen species (ROS) and callose when delivered by Pseudomonas fluorescens heterologously expressing a P. syringae T3SS. Purified His(6) -tagged HopN1 was used to identify tomato PsbQ, a member of the oxygen evolving complex of photosystem II (PSII), as an interacting protein. HopN1 localized to chloroplasts and both degraded PsbQ and inhibited PSII activity in chloroplast preparations, whereas a HopN1(D299A) non-catalytic mutant lost these abilities. Gene silencing of NtPsbQ in tobacco compromised ROS production and programmed cell death by DC3000. Our data reveal PsbQ as a contributor to plant immunity responses and a target for pathogen suppression. © 2012 Blackwell Publishing Ltd.

Inzicht in het presteren van de executieketen : Ontwikkeling van een monitor voor het meten van Kritieke Prestatie Indicatoren in de Executieketen

NARCIS (Netherlands)

Braak, S.W. van den; Netten, C.P.M.; Witzenburg, R. van

2013-01-01

Dit zijn de voorlopige resultaten van het ontwikkelprojcet Monitor Kritieke Prestatie Indicatoren Executieketen. Het structureel meten van de vastgestelde Kritieke Prestatie Indicatoren (KPI's) behelst het periodiek verzamelen, bewerken en presenteren van grote hoeveelheden data van verschillende

Vergelijking van vangsten van een 12 m pulskor met een conventionele wekkerboomkor

NARCIS (Netherlands)

Marlen, van B.; Ybema, M.S.; Kraayenoord, A.; Vries, de M.; Rink, G.J.

2005-01-01

In het kader van de ontwikkeling van een pulskor als alternatief voor de conventionele boomkor met wekkerkettingen werd in nov-dec 2004 en jan 2005 onderzoek uitgevoerd op het visserij-onderzoekingsvaartuig “Tridens” naar de vangstverschillen van beide visserijtechnieken en de overleving van door

Het gebruik van antropometrische gegevens bij het opstellen van normen voor kantoorstoelen

NARCIS (Netherlands)

Groot, M.D. de; Voorbij, A.I.M.; Molenbroek, J.F.M.

2003-01-01

De fysieke belasting van werknemers is bij het invoeren van de personal computer veranderd. De werkplekken zijn zitplekken geworden. Het aantal gebruikers van kantoorstoelen is daarmee enorm toegenomen. Achter een monitor zitten mensen vaak lang achter elkaar in dezelfde houding, wat in weerwil van

De verleidelijkheid van het grote gebaar : Het werk van Dogma

NARCIS (Netherlands)

Teerds, P.J.

2013-01-01

In vier portacabins op het parkeerterrein van de Delftse Faculteit Bouwkunde is nog tot volgende week de tentoonstelling 11+1 projects te zien, een overzichtstentoonstelling van het intrigerende werk van het Brusselse bureau Dogma. Met de tentoonstelling zet de faculteit na de brand in 2008 weer een

De afschaffing van de bezwaarfase bij boetebesluiten van de ACM

NARCIS (Netherlands)

Jans, J.H.; Outhuijse, A.

Per 1 maart 2013 ontstaat door samenvoeging van de NMa, de OPTA en de Consumentenautoriteit, de Autoriteit Consument en Markt. Om de ACM slagvaardig te laten functioneren, wordt voorgesteld het handhavingsinstrumentarium m.b.t. het markttoezicht van de ACM te vereenvoudigen. Eén van de voorstellen

Implementatie van de Surviving Sepsis Campaign bundels : Monitoring van ervaringen

NARCIS (Netherlands)

Lilian Vloet; J. Schouten; N. Stevens; A. Rensen; A. Willems; F. Zeegers

2011-01-01

Sepsis komt vaak voor in ziekenhuizen. Ernstige sepsis is verantwoordelijk voor 10 - 20% van alle Intensive Care (IC) opnames en is de belangrijkste doodsoorzaak op niet-cardiale IC?s. De gemiddelde mortaliteit van volwassenen met ernstige sepsis op de IC is 33% en van volwassenen met septische

Omkering van de bewijslast: knelpunten in de regeling en bij de toepassing van de omkering van de sanctie (deel I)

NARCIS (Netherlands)

Okhuizen, E.C.G.

2013-01-01

De omkering van de bewijslast als processuele sanctie op het niet nakomen van de aangifteplicht en de daaraan verbonden bijkomende verplichtingen lijken niet weg te denken uit ons belastingrecht. De sanctie kwam al voor in de fiscale wetgeving die dateert van vóór de invoering van de Algemene wet

Vervluchtiging van EPTC, tri-allaat en parathion na bespuiting van een kleigrond

NARCIS (Netherlands)

Bor, G.; Berg, van den F.; Smelt, J.H.; Peppel-Groen, van de A.E.; Leistra, M.

1995-01-01

Op tien tijdstippen na de bespuiting van een onbegroeide kleigrond met EPTC, tri-allaat en parathion werden de snelheden van vervluchtiging van deze middelen bepaald met de kapmethode en de theoretisch-profielmethode (TP-methode). De vervluchtiging was het hoogst op de dag van toepassing. In de

Enkele aspecten van de diagnostiek van hypophysaire insufficiëntie bij kinderen

NARCIS (Netherlands)

Israëls, Albertus Leonard Maurits

1960-01-01

In dit proefschrift is een onderzoek beschreven, dat naar de functie van de hypophyse bij kinderen met tekenen van hypophysaire insufficiëntie werd ingesteld. Het onderzoek werd in de kinderkliniek van het Academisch Ziekenhuis te Groningen verricht. In hoofdstuk I is een overzicht van de literatuur

VT-NRK Toepassing bioplastics : verbeteren van de technische eigenschappen van PLA-folies

NARCIS (Netherlands)

Molenveld, K.; Schennink, G.G.J.

2009-01-01

Het doel van dit project, VT-NRK toepassing bioplastics, is het genereren en verspreiden van kennis met betrekking tot het verbeteren van de technische eigenschappen van PLA folies. De kennis is bedoeld voor de bedrijven die binnen de kunststofindustrie aangesloten zijn bij de MJA én folies

Rituele van plesier: Dolf van Coller se Die Bieliebalies

Directory of Open Access Journals (Sweden)

J. van Wyk

1998-04-01

Full Text Available Rituals of pleasure: Dolf van Coller’s Die Bieliebalies This article is an analysis of Dolf van Coller's Die Bieliebalies (1993, read as a hedonist text. It has many points of similarity with what Bakhtin (1984 called grotesque realism, and with Nietzsche’s views as expounded in The birth of tragedy (1956. By comparing Van Caller's text to that of Bakhtin and Nietzsche, a counter-discourse to contemporary moral discourses such as feminism is explored. Van Coller’s use of laughter as a relativising mechanism is very liberating in the context where petty morality intervenes dogmatically in the field of literature and other spheres of life.

Die ontwikkeling van menslike potensiaal in die Republiek van Suid ...

African Journals Online (AJOL)

Erna Kinsey

Dit het dus ook te doen met lewenstandaard, aangesien lewenstandaard `n bepalende faktor is met betrekking tot die optimale ontwikkeling van menslike potensiaal. Ander minder materiële aspekte van menslike potensiaal het te doen met menslike vryheid, waaronder vryheid van spraak, beweging en keuse ter sake is.

Katalytisch verbranden van varkensmest

NARCIS (Netherlands)

Hendriks, J.

1995-01-01

Door het verbranden van mest kan het mestvolume worden verkleind. Binnenkort gaat op het Varkensproefbedrijf 'Zuid- en West-Nederland' in Sterksel onderzoek van start om de mogelijkheden van het katalytisch verbranden van varkensmest te bekijken.

Witte vlekken in het bereik van NME? : raamwerk voor het meten van gebruik en de effecten van NME in het primair onderwijs

NARCIS (Netherlands)

Vreke, J.; Langers, F.; Berg, van den A.E.

2011-01-01

In het NME-beleid wordt het geven van NME ingezet als instrument om bij te dragen aan het reduceren van de achteruitgang, in omvang en kwaliteit, van natuur en milieu. Het bereik van NME moet aangeven in hoeverre NME de bevolking heeft bereikt en aan dit doel heeft bijgedragen. Het identificeren van

Produktie van pigmenten

NARCIS (Netherlands)

Etman EJ; Duesmann HB; Eijssen PHM; LAE

1994-01-01

Dit rapport over de produktie van pigmenten is gepubliceerd binnen het Samenwerkingsproject Procesbeschrijvingen Industrie Nederland (SPIN). In het kader van dit project is informatie verzameld over industriele bedrijven of industriele processen ter ondersteuning van het overheidsbeleid op het

Het effect van het bijvoeren van tarwe aan vleeskuikens op de slachtrendementen

NARCIS (Netherlands)

Middelkoop, van J.H.; Harn, van J.

1994-01-01

Tarwe bijvoeren aan vleeskuikens staat momenteel volop in de belangstelling. Redenen hiervoor zijn de lage prijs van de tarwe en het positieve effect dat tarwe kan hebben op de resultaten en gezondheid van de koppel. Door het bijvoeren van tarwe wordt de werking van de spiermaag en de ontwikkeling

St. Teresa van Avila: sentrale figuur in die werk van Cussons en Van Wyk Louw

Directory of Open Access Journals (Sweden)

H. van Vuuren

1989-05-01

Full Text Available A central poem in Van Wyk Louw’s Tristia (1962, is “H. Teresa van Avila flap uit” (literally translated: “Saint Teresa of Avila talks too much/babbles uncontrollably”. This article illustrates how intertextual reading helped to clarify the poem. Teresa of Avila’s The way of perfection (a translation of the Spanish work El Camino de la Perfección, 1573 is the intertext of the Van Wyk Louw poem. In the last section of the article it is shown how the figure of St. Teresa of Avila is central not only to Van Wyk Louw’s Tristia (1962, but also to the oeuvre of Sheila Cussons, which underlines a strong intertextuality between these two Afrikaans oeuvres.

Die gebruik van ’n reologiese tegniek in die bepaling van die verhardingsreaksiekinetika van ’n reaktiewe poliësterpoeierdeklaag

Directory of Open Access Journals (Sweden)

O. C. Vorster

2004-09-01

Full Text Available

Die studie van die verhardingsreaksiekinetika van deklae word bemoeilik deur die aanwesigheid van vlugtige stowwe, pigmente en bypigmente. In hierdie studie word die verhardingsreaksiekinetika van ’n karboksielgetermineerde poliëstertriglisediel-isosianuraat deur middel van parallelplaatspanningsreometrie bepaal. Jeltye is verkry en skaleringseksponente bepaal. ’n Nuwe metode vir die voorspelling van die verloop van die reaksie word voorgestel en vergelyk met resultate verkry deur middel van differensiël skanderingskalorimetrie.

Abstract

The use of a rheological technique in the determination of the curing kinetics of a reactive polyester powder coating

In this article a study of the curing process of carboxyl terminated polyester-triglycidyl isocyanurate systems is reported. A comparison is made between the generally used Differential Scanning Calorimetric methods and rheokinetic methods, using a parallel plate oscillating stress rheometer. Gel times were determined and scaling exponents calculated. A new method for the estimation of the extent of reaction is presented and compared with results obtained by means of differential scanning calorimetry

Handelsstromen van pluimveevlees

NARCIS (Netherlands)

Tacken, G.M.L.; Horne, van P.L.M.

2006-01-01

Dit onderzoek geeft inzicht in de goederenstromen van (rauw) pluimveevlees binnen envooral naar Nederland en de daarmee gepaard gaande zoönoserisico's. Het onderzoek biedtinput voor het nog op te zetten controlebeleid, waarmee handhaving van het beleidsvoornemenom het aanbieden van rauw

Abscisic acid has a key role in modulating diverse plant-pathogen interactions

Science.gov (United States)

Jun Fan; Lionel Hill; Casey Crooks; Peter Doerner; Chris Lamb

2009-01-01

We isolated an activation-tagged Arabidopsis (Arabidopsis thaliana) line, constitutive disease susceptibility2-1D (cds2-1D), that showed enhanced bacterial growth when challenged with various Pseudomonas syringae strains. Systemic acquired resistance and systemic PATHOGENESIS-RELATED GENE1 induction were also compromised in cds2-1D. The T-DNA insertion adjacent to NINE...

Bekalking en toevoegen van nutriënten; evaluatie van de effecten op de vitaliteit van het bos; een veldonderzoek naar boomgroei

NARCIS (Netherlands)

Wolf, R.J.A.M.; Engels, M.E.; Knotters, M.; Schraven, R.; Boertjes, M.

2006-01-01

Dit rapport doet verslag van een deelonderzoek uit de Evaluatie van effectgerichte maatregelen in multifunctionele bossen 2004-2005 en is gericht op de effecten van de maatregelen bemes-ting en bekalking in bossen als overbruggingsmaatregel in het kader van het Overlevingsplan Bos en Natuur (OBN).

Die berekening van vloeiing in ’n roterende annulus deur die metode van kunsmatige saamdrukbaarheid

Directory of Open Access Journals (Sweden)

H. Grobler

1987-03-01

Full Text Available Die vloeiing van ’n onsaamdrukbare, viskeuse vloeier word ondersoek aan die hand van die numeriese oplossing van die gediskretiseerde Navier-Stokes- en kontinuiteitsbeheervergelykings. In die besonder word vloeiing in ’n annulus bestaande uit twee koaksiale silinders wat elk ten opsigte van die ander kan roteer, en met ’n voorgeskrewe drukval oor die lengte van die silinder, beskou. Die oplossings word bereken deur die toepassing van Chorin se metode van kunsmatige saamdrukbaarheid, waarin die tydonafhanklike beheervergelykings getransformeer word na tydafhanklike hulpvergelykings deur die invoering van ’n kunsmatige toestandsvergelyking. Die oplossing van die hulpvergelykings konvergeer na ’n stasionêre oplossing, wat ooreenstem met die oplossing van die oorspronklike tydonafhanklike beheervergelykings. Die gedrag van die vloeier, wanneer ten voile ontwikkelde laminêre vloeiing bereik word, is met sukses bereken. ’n Eenvoudige model vir die bepaling van ontwikkeling van vloeiing langs die annulus vir enige gegewe invloeisnelheidsprofiel word voorgestel. Die berekende resultate stem ooreen met die resultate wat uit die fisika van die probleem verwag word.

Het format van de stad. Een evaluatie van recente Nederlandse stadsgeschiedenissen

Directory of Open Access Journals (Sweden)

P. Kooij

2002-01-01

Full Text Available R. Kunst, Leeuwarden 750-2000. Hoofdstad van Friesland; A. van der Schoor, N. Schadee, Stad in aanwas. Geschiedenis van Rotterdam tot 1813; P. van de Laar, Stad van formaat. Geschiedenis van Rotterdam in de negentiende en twintigste eeuw; R.E. de Bruin, 'Een paradijs vol weelde'. Geschiedenis van de stad Utrecht.The shape of the city. An evaluation of recent historical studies on Dutch townsUrban history in the Netherlands started roundabout 1970. It was initially promoted by mainly economic and social historians who used concepts derived from geography which centred on town and country relations, urban networks, and migration. The spatial factor was considered to be a core feature, also inside the towns and cities. An alternative view, however, argued that a completely introspective urban history, focussing on one city, would result in more integration. This hypothesis has been proved in a number of recent, more or less integral urban histories, commissioned by several independent municipal authorities in individual cities. They show that a combination of internal and external elements offers the best results with regard to integration.

Psigologiese benadering van pastorale arbeid

Directory of Open Access Journals (Sweden)

D. J. Strümpfer

1969-03-01

Full Text Available In die spreektaal van ons Afrikaanse kerke is ons lief om die bedienaar van die Woord aan te dui as „die predikant”, „die leraar” of „die dominee”. Miskien plaas ons met hierdie semantiese gebruik van terme wat lering en proklamering impliseer, ’n ongelukkige klem op die preekamp. Daarteenoor, het ons semanties miskien iets te leer van die Pinkstersektes wat die benaming „pastoor” verkies, of die Amerikaanse ge­ bruik van die term „the pastor”. Ons is wel lief om te praat van „ons herder en leraar”. Veelal word die herderlike, of pastorale, deel van die taak van die bedienaar van die Woord egter in sy eie gedagtes, asook in die gedagtes van sy gemeentelede, deur die leraarskap op die agtergrond gedwing. Al te dikwels word hy deur gemeentelede beskou as iemand wat op Sondag op die kansel gesien moet word en wat niks met die res van hul lewens te doen het nie. Herstel van die pastoraat sal deel moet wees van die proses om die ontkerstening van die hedendaagse lewe teen te gaan.

Pseudomonas wadenswilerensis sp. nov. and Pseudomonas reidholzensis sp. nov., two novel species within the Pseudomonas putida group isolated from forest soil.

Science.gov (United States)

Frasson, David; Opoku, Michael; Picozzi, Tara; Torossi, Tanja; Balada, Stefanie; Smits, Theo H M; Hilber, Urs

2017-08-01

Within the frame of a biotechnological screening, we isolated two Pseudomonas strains from forest soil. 16S rRNA gene sequence analysis indicated that strain CCOS 864T shared 99.8 % similarity with Pseudomonas donghuensis HYST, while strain CCOS 865T shared 99.0 % similarity with Pseudomonas putida DSM 291T and lower similarity with other P. putida group type strains. Based on multilocus sequence analysis, the two strains were genotypically distinct from each other, each forming a separate clade. Strains CCOS 864T and CCOS 865T were Gram-stain-negative, motile and rod-shaped, growing at a temperature range of 4-37 °C. Strain CCOS 864T could be phenotypically distinguished from P. putida group species by the combination of gelatinase-positive reaction and positive growth on N-acetyl-d-glucosamine, p-hydroxyphenylacetic acid and inosine but lack of fluorescein production on King's B medium, while strain CCOS 865T could be distinguished from P. putida group species by the combination of positive growth with saccharic acid and negative growth with p-hydroxyphenylacetic acid and l-pyroglutamic acid. The major polar lipid for both strains was phosphatidylethanolamine; the major quinone was ubiquinone Q-9. DNA-DNA hybridization and average nucleotide identities confirmed the novel species status for the two strains. The DNA G+C contents of CCOS 864T and CCOS 865T were 62.1 and 63.8 mol%, respectively. The phenotypic, phylogenetic and DNA-DNA relatedness data support the suggestion that CCOS 864T and CCOS 865T represent two novel Pseudomonas species. The names Pseudomonas wadenswilerensis sp. nov. (type strain CCOS 864T=LMG 29327T) and Pseudomonas reidholzensis sp. nov. (type strain CCOS 865T=LMG 29328T) are proposed.

High pressure inactivation of Pseudomonas in black truffle - comparison with Pseudomonas fluorescens in tryptone soya broth

Science.gov (United States)

Ballestra, Patricia; Verret, Catherine; Cruz, Christian; Largeteau, Alain; Demazeau, Gerard; El Moueffak, Abdelhamid

2010-03-01

Pseudomonas is one of the most common genera in black Perigord truffle. Its inactivation by high pressure (100-500 MPa/10 min) applied on truffles at sub-zero or low temperatures was studied and compared with those of Pseudomonas fluorescens in tryptone soya broth. Pressurization of truffles at 300 MPa/4 °C reduced the bacterial count of Pseudomonas by 5.3 log cycles. Higher pressures of 400 or 500 MPa, at 4 °C or 20 °C, allowed us to slightly increase the level of destruction to the value of ca. 6.5 log cycles but did not permit us to completely inactivate Pseudomonas. The results showed a residual charge of about 10 CFU/g. Pressure-shift freezing of truffles, which consists in applying a pressure of 200 MPa/-18 °C for 10 min and then quickly releasing this pressure to induce freezing, reduced the population of Pseudomonas by 3.3 log cycles. The level of inactivation was higher than those obtained with conventional freezing. Endogenous Pseudomonas in truffle was shown to be more resistant to high pressure treatments than P. fluorescens used for inoculation of broths.

Verlies van (thuis en haard. Het belang van verliesbegeleiding als onderdeel van de maatschappelijke begeleiding binnen het Vluchtelingenwerk, regio Utrecht

Directory of Open Access Journals (Sweden)

Birgit Hoogenberk

2014-06-01

Full Text Available Loss of home and house. The importance of loss counseling as a part of refugee social supportIn this article it is advocated that it is important that the implementation of loss counseling is part of social support for refugees, also called integrative eclectic working. Social support from VluchtelingenWerk, also known as Refugee Council, is about supporting the client in an effective manner with their personal problems which can hinder their integration. Because the target group of VluchtelingenWerk is a group of people whom have suffered many losses, attention should be brought to this subject. Unfortunately in current work methods there is no room for loss counseling, partly due to the lack of methodological tools. The losses associated with this group have a lot of impact on their daily lives and often are the source of functional limitations. By offering loss counseling and multi-method grief counseling, volunteers and employees are offered tools to make loss more negotiable. In this article different examples will be discussed and the new loss model of Stroebe and Schut will be explained. What will be clarified is the importance of the implementation of loss counseling, for the well-being and the integration process of clients as well as achieving organizational goals.Verlies van (thuis en haard. Het belang van verliesbegeleiding als onderdeel van de maatschappelijke begeleiding binnen het VluchtelingenWerk, regio UtrechtIn dit artikel wordt gepleit voor het implementeren van verliesbegeleiding als onderdeel van de maatschappelijke begeleiding, er is sprake van integratief eclectisch werken. De maatschappelijke begeleiding van het VluchtelingenWerk heeft als taak de cliënt zo goed mogelijk te begeleiden bij persoonlijke problemen die de inburgering kunnen belemmeren. Aangezien de doelgroep van het VluchtelingenWerk bestaat uit mensen die ontzettend veel verliezen hebben geleden dient hier aandacht voor te zijn. Helaas is in de huidige

Economische gevolgen van ontwapening

NARCIS (Netherlands)

Duisenberg, Willem Frederik

1965-01-01

Samenvatting van de gehele studie 4.1. Economie en ontwapening Ontwapening betekent in deze studie de algehele, snelle afschaffing van alle militaire maatregelen in aIle landen. Het negeren van de politieke waarschijnlijkheden die veeleer wijzen op een zeer geleidelijke afschaffing van slechts

Neurotoxische effecten van broomcyclohexaan

NARCIS (Netherlands)

Velsen; F.L.van; Danse; L.H.J.C.; Vries; L.J.de; Liefde; A.de

1984-01-01

Kortdurende toediening (4-7 dagen) van broomcyclohexaan (BCH) veroorzaakt in een dosering van 1200 mg/kg lichaamsgewicht (per maagsonde) necrose van gegranuleerde cellen in de korrellaag van de kleine hersenen. In deze doseringen zijn ook gedragsafwijkingen waargenomen d.m.v. een objectieve

Evaluatie van het gebruik van de iPad in het klaslokaal : Een onderzoek naar het iPadgebruik onder brugklasleerlingen van een Leeuwarder Lyceum

NARCIS (Netherlands)

Klaas Jan Huizing; Chantal Philipsen; Luka Linster

2013-01-01

In november 2012 kregen alle brugklasleerlingen van het Leeuwarder Lyceum een iPad uitgereikt. Dit nieuwe ‘device’ is de aanjager van onderwijsvernieuwingen op het gebied van digitalisering van lesmateriaal. Sowijs volgde de implementatie van de iPad en vroeg zich af: hoe is het iPadgebruik na een

Leven en werken van Geert Reinders. De grondlegger van de immunologie.

NARCIS (Netherlands)

Bruins, Luitje Hendrik

1951-01-01

De levensgeschiedenis van Geert Reinders is het relaas van de vele prestaties, waartoe deze man ondanks een zeer gebrekkige schoolopleiding in staat was. Hij was werkzaam als molenaar, boer, koopman, redger, gemeentesecretaris, secretaris en ontvanger van een groot zijlvest, veeartsenijdeskundige;

Die rol van die blanke werker in die motivering van die swart werker

Directory of Open Access Journals (Sweden)

G. J. Oosthuizen

1980-11-01

Opsomming Die motivering van die Swart werker kan nie in die huidige situasie in isolasie bestudeer word nie, omdat die Blanke werker steeds in die bestuursposisie is en daarom die motivering van die Swart werker kan beïnvloed. Hierdie ondersoek was daarop gerig om die rol van die Blanke werker in die motivering van die Swart werker nader te ondersoek. Die houding en die leierskapsbenadering van die Blanke werker teenoor die Swart werker is gemeet, asook die behoeftes wat volgens die Blanke werker by die Swart werker bestaan, bevredig is, of nie bestaan nie. Die behoeftes van Swart werkers, soos deur hulleself gesien, is ook ondersoek. Ten opsigte van sekere aspekte is beduidende verskille gevind.

De eeuw van de Beeldenstorm

Directory of Open Access Journals (Sweden)

F. Postma

1988-01-01

Full Text Available P. van Boheemen, N.P.J. van der Lof, E. van Meurs, Het boek in Nederland in de 16e eeuw S. Groenveld, Ketters en papen onder Filips II. Het godsdienstig leven in de tweede helft van de zestiende eeuw R. Kistemaker, M. Jonker, De smaak van de elite. Amsterdam in de eeuw van de Beeldenstorm W.Th. Kloek, Kunst voor de Beeldenstorm. Noord-Nederlandse kunst ca 1525-1580, [I], Inleiding, [II, Catalogus] J.R. ter Molen, A.P.E. Ruempol, A.G.A. Dongen, Huisraad van een molenaarsweduwe. Gebruiksvoorwerpen uit een 16e eeuwse boedelinventaris M. de Roever, B. Bakker, Woelige tijden. Amsterdam in de eeuw van de Beeldenstorm I.M. Veldman, Leerrijke reeksen van Maarten van Heemskerck

Benaderingen van over

NARCIS (Netherlands)

Boer, M.G. de

2010-01-01

SAMENVATTING In dit hoofdstuk wordt de relatie tussen de betekenissen van het Nederlandse voorzetsel over en een aantal corpora bestudeerd. Het hoofdstuk begint met een analyse van de voorbeelden uit Uit het leven van Dik Trom (1891); daarna wordt de woordenboekinformatie behandeld en vergeleken

Die effek van intelligensie op die verhouding tussen lokus van kontrole en taakkompleksiteit

Directory of Open Access Journals (Sweden)

F. G. de Kock

1995-06-01

Full Text Available The effect of intelligence on the relationship between locus of control and task complexity. The aim of the study was to establish the effects of intelligence on the relationship between locus of control and task complexity. These constructs were selected by virtue of their importance in the literature, as well as the lack of empirical research regarding the assumed relationship which exists between them. The Human Sciences Research Council's (HSRC General Scholastic Aptitude Test (ASAT was used for measuring intelligence, Duttweiler's Internal Control Index (ICI was used for determining locus of control and the Raven's Advanced Progressive Matrices (APM was used as a criterion for coping with task complexity. These instruments were administered to 292 subjects to determine whether the relationship between locus of control and task complexity was effected when the effect of intelligence was controlled. The results indicated a significant relationship between locus of control and task complexity, however the relationship was no longer significant after the effect of intelligence was controlled. Opsomming Die doel van die studie was om die effek van intelligensie op die verhouding tussen lokus van kontrole en taak-kompleksiteit te ondersoek. Hierdie konstrukte is gekies na aanleiding van hulle belangrikheid in die literatuur asook die leemte in empiric se navorsing rakende die veronderstelde verband wat tussen hulle bestaan. Die Algemene Skolastiese Aanlegtoets (ASAT van die Raad vir Geesteswetenskaplike Navorsing (RGN is gebruik vir die meting van intelligensie, die Internal Control Index (ICI van Duttweiler is gebruik vir die meting van lokus van kontrole en die Advanced Progressive Matrices (APM van Raven is gebruik as maatstaf vir die bantering van taakkompleksiteit. Die genoemde meetinstrumente is op 292 proefpersone toegepas om te bepaal of die verband tussen lokus van kontrole en taakkompleksiteit geaffekteer word wanneer daar vir die effek

Ziekten van het ruggenmerg

NARCIS (Netherlands)

Groen, Robertus; Kuks, Joannes; Snoek, Jozef; Kuks, Jan B.M.; Snoek, Jos W.

2016-01-01

Er zijn vele oorzaken voor een myelopathie. Beschadiging van het myelum kan compleet zijn (zoals in het geval van een complete dwarslaesie), maar is vaker incompleet (zoals bij een incomplete traumatische dwarslaesie en de meeste vormen van myelopathie op basis van niet-traumatische oorzaken). Er

Analyse van de vervormingen van de Fusee Ceramique daken van de productiehallen in Dongen : Rapport met bevindingen betreffende de vervormingen van de Fuseedaken van de productiehallen van Coca Cola in Dongen

NARCIS (Netherlands)

Kamerling, M.W.

2014-01-01

In 1962 werden in Dongen bedrijfshallen gemaakt met cilindervormige overkappingen waarin ter besparing van gewicht en cement ceramische elementen, de Fusée's Ceramique, werden gelegd. De schalen worden ondersteund met balken 450*750 mm2 en kolommen 450 * 450 mm2 op een raster van 5,6 m * 20,4 m. Het

Effectiviteit van facultatief aansluitonderwijs wiskunde in de transitie van voortgezet naar hoger onderwijs

NARCIS (Netherlands)

Tempelaar, D.T.; Rienties, B.; Kaper, W.; Giesbers, B.; Gastel, van L.J.; Vrie, van de E.M.; Kooij, van der H.; Cuypers, H.

2011-01-01

Samenvatting Wat is het effect van vrijwillig aansluitonderwijs, zoals het remediërend wiskundeonderwijs dat op veel instellingen voor hoger onderwijs wordt gegeven ter verbetering van de doorstroom? Bepaling van de doelmatigheid van dit onderwijs wordt bemoeilijkt door selectie-effecten die kunnen

De opdeling van Centraal-Afrika, 1875-1885 : een analyse van twee territoriale conflicten

NARCIS (Netherlands)

Foeken, D.W.J.

1992-01-01

Deze studie beschrijft een politiek-historisch proces en vormt een bijdrage aan de systematische studie van internationale territoriale conflicten vanuit het gezichtspunt van de politieke geografie. Tevens worden aspecten van het Europese imperialisme van de late 19e eeuw nader verklaard. De

De economische kracht van de baggerindustrie: clusterstudie met behulp van de 'methode Porter'

NARCIS (Netherlands)

Jacobs, D.; Limpens, I.; Kuijper, J.; Ven, B. van de

1993-01-01

Deze clusterstudie van de Nederlands-Belgische baggerindustrie is uitgevoerd in opdracht van IHC Holland, de belangrijkste bouwer van baggerschepen ter wereld, en de Vereniging Centrale Baggerbedrijf, de branche-organisatie van aannemers in de bagger. De bedoeling is een beter inzicht te krijgen in

Pseudomonas Lipopeptide Biosurfactants

DEFF Research Database (Denmark)

Bonnichsen, Lise

Pseudomonas lipopetide biosurfactants are amphiphilic molecules with a broad range of natural functions. Due to their surface active properties, it has been suggested that Pseudomonas lipopetides potentially play a role in biodegradation of hydrophobic compounds and have essential functions...... lipopetide biosurfactants in pollutant biodegradation and natural roles in biofilm formation. The work presented is a combination of environmental microbiology and exploiting genetic manipulation of pure cultures to achieve insightinto the effects and mechanisms of lipopeptides on microbial processes...

Maatskaplike aspekte van geriatriese sorg

Directory of Open Access Journals (Sweden)

D. Louw

1979-09-01

Full Text Available Dit is maar enkele dekades gelede dat Westerse gemeenskappe bewus geword het van die besondere behoeftes van die relatief groot en nog steeds groeiende persentasie bejaardes in hulle midde. Nie alleen het die liggaamlike behoeftes van liggaamlike afgetakelde bejaardes die aandag getrek nie maar die gemeenskappe het ook bewus geword van die maatskaplike behoeftes van ouerwordendes in ’n tydperk wat gekenmerk is deur die dramatiese veranderings in die lewenswyses van ons mense — veranderinge wat in baie opsigte ’n negatiewe invloed gehad het op die lewensomstandighede van ’n groot groep bejaardes. Welsynsbeplanners het besef dat hulle in hulle beplanning spesiale voorsiening moes maak vir die lewensbehoeftes van hierdie groep in die gemeenskap en dat hulle in die verband ’n groot agterstand het om in te haal. Geneeshere wat belang begin stel het in die gesondheidsbehoeftes van bejaardes het ook besef dat gevestigde geneeskundige praktyke geensins voldoen aan die spesifieke behoeftes van ’n groot groep bejaardes nie en dat groot aanpassings gemaak moes word met betrekking tot hulle benaderings en metodes van behandeling van hierdie pasiente.

Betekenis van Legionella-soorten voor preventiebeleid van leidingwaterinstallaties

NARCIS (Netherlands)

Versteegh JFM; Brandsema PS; Lodder WJ; de Roda Husman AM; Schalk JAC; van der Aa NGFM; IMG; LZO; EPI

2009-01-01

Het RIVM adviseert om de huidige normstelling voor het preventiebeleid van Legionella te handhaven en niet uitsluitend op Legionella pneumophila te richten. Als andere Legionella-soorten worden aangetroffen kan er ook groei van Legionella pneumophila optreden. Als er dan geen maatregelen worden

Plausibiliteitsdocument STONE 2.0 (Globale verkenning van de plausibiliteit van het model STONE versie 2.0 voor de modellering van uit- en afspoeling van N en P).

NARCIS (Netherlands)

Overbeek, G.B.J.; Beusen, A.H.W.; Boers, P.C.M.; Born, van den G.J.; Groenendijk, P.; Grinsven, van J.J.M.; Kroon, T.; Meer, van der H.G.; Oosterom, H.P.; Puijenbroek, van P.J.T.M.; Roelsma, J.; Roest, C.W.J.; Rötter, R.; Tiktak, A.; Tol, van S.

2002-01-01

STONE is ontwikkeld om landsdekkend voor Nederland de effecten van bemesting en mestbeleid op de emissies van stikstof en fosfaat uit de landbouw naar grond- en oppervlaktewater te verkennen. De nadruk in de hier gerapporteerde plausibiliteitsstudie ligt op vaststelling van de geloofwaardigheid, het

Plausibiliteitsdocument STONE 2.0.Globale verkenning van de plausibiliteit van het model STONE versie 2.0 voor de modellering van uit -en afspoeling van N en P

NARCIS (Netherlands)

Overbeek GBJ; Beusen AHW; Boers PCM; Born GJ van den; Groenendijk P; Grinsven JJM; Kroon T; Meer HG van der; Oosterom HP; Puijenbroek PJTM van; Roelsma J; Roest CJW; Rotter R; Tiktak A; Tol S van; LBG; CIM; LAE; LWD

2002-01-01

STONE is ontwikkeld om landsdekkend voor Nederland de effecten van bemesting en mestbeleid op de emissies van stikstof en fosfaat uit de landbouw naar grond- en oppervlaktewater te verkennen. De nadruk in de hier gerapporteerde plausibiliteitsstudie ligt op vaststelling van de geloofwaardigheid,

Geochemische bodematlas van Nederland

NARCIS (Netherlands)

Mol, G.; Spijker, J.H.; Gaans, van P.; Römkens, P.F.A.M.

2012-01-01

Deze Geochemische bodematlas geeft een uniek overzicht van de chemische samenstelling van de bodem in Nederland. Bodemmonsters van meer dan 350 locaties zijn geanalyseerd op meer dan 40 chemische elementen. De atlas geeft niet alleen informatie over de door de mens beïnvloede toplaag van de bodem,

Evaluatie van bemesting en bekalking in bossen en de ontwikkeling van onbehandelde bossen

NARCIS (Netherlands)

Olsthoorn, A.F.M.; Berg, van den C.A.; Gruijter, de J.J.

2006-01-01

Dit rapport doet verslag van een deelonderzoek uit de Evaluatie van effectgerichte maatregelen in multifunctionele bossen 2004-2005 en is gericht op de effecten van de maatregelen bemesting en bekalking in bossen als overbruggingsmaatregel in het kader van het Overlevingsplan Bos en Natuur (OBN). Na

Die meting van die gelyktydige hantering van teenstrydige en dubbelsinnige inligting as kritieke eienskap in 'n verskeidenheid van Beroepe

Directory of Open Access Journals (Sweden)

W. S. de Villiers

1983-11-01

Min informasie bestaan omtrent die hantering van teenstrydige en dubbelsinnige inligting as kritieke vermoë in vele werksituasies. Met hierdie ondersoek is daar gepoog om die konstruk te omlyn en aan 'n empiriese verifiering te onderwerp. ‘n Meetinstrument (posmandjie is ontwikkel om die hantering van teenstrydige en dubbelsinnige inligting te meet en is saam met ander meetinstrumente ter omlyning van die genoemde konstruk aan twee groepe proefpersone geadministreer. Daar is vasgestel dat hierdie vermoë verband hou met intellektuele vermoëns en sensories kognitiewe oordeel en nie met sekere persoonlikheids- en ander determinante van mens like gedrag nie en dat dit na alle waarskynlikheid dui op die bestaan van 'n afsonderlike werksvermoë of konstruk.

Een traditie herneemt zich - Over het belang van Aldo van Eyck

NARCIS (Netherlands)

Colenbrander, B.J.F.

1997-01-01

Zo'n zeven, acht jaar geleden veranderde Aldo van Eyck, overigens bij leven en welzijn, van een lijfelijk deelnemer aan de architectuurdiscussie in een historische figuur. Hij werd verguisd en gelauwerd. Met de Rekenkamer in Den Haag echter doet Van Eyck lang vergeten manifesten herleven. Gloort er

Het belang van beschermende factoren in de risicotaxatie van tbs-gestelden

NARCIS (Netherlands)

Nagtegaal, M.H.; Schönberger, H.J.M.

2013-01-01

In dit onderzoek staan de volgende vragen centraal: Is het meenemen van beschermende factoren van toegevoegde waarde voor de risicotaxatie zoals deze plaatsvindt in de tbs-praktijk? Zo ja, op welke manier? Hierbij wordt onder ander het belang van beschermende factoren voor de behandelpraktijk en de

Een geschiedenis van vleesloos eten

NARCIS (Netherlands)

Dagevos, H.

2009-01-01

Recensie van de populaire editie van het proefschrift van Dirk-Jan Verdonk: Het dierloze gerecht: een vegetarische geschiedenis in Nederland. Hierin wordt de geschiedenis van het vegetarisme vanaf de tweede helft van de 19e eeuw tot nu beschreven

Een nieuwe ondersoort van Zosterops montana afkomstig van de Goenoeng Papandajan (West Java)

NARCIS (Netherlands)

Hoogerwerf, A.; Boer, de L.E.

1947-01-01

In zijn laatste revisie van het genus Zosterops (Journ. für Orn., vol. 87, 1939, p. 156-164) geeft Stresemann o.a. een schematische voorstelling van de horizontale en verticale verspreiding binnen deze Archipel van de vier voornaamste groepen van dit geslacht: montana, atricapilla, palpebrosa en

Naar meer bruto nationaal sportgeluk? Verkenning van de rol van sport in geluk

NARCIS (Netherlands)

Dool, R. van den; Breedveld, K.

2017-01-01

Op verzoek van NOC*NSF heeft het Mulier Instituut, met financiële steun van het ministerie van VWS, een verkenning uitgevoerd naar de relatie tussen sport en geluk. NOC*NSF en de Nederlandse sportbonden streven, als onderdeel van het 'transitietraject', ernaar om duidelijker voor het

Isolation and Identification of Endophytic Bacteria with Plant Growth Promoting Activity and Biocontrol Potential from Wild Pistachio Trees

Science.gov (United States)

Etminani, Faegheh; Harighi, Behrouz

2018-01-01

In this study, samples were collected from the leaves and stems of healthy wild Pistachio trees (Pistacia atlantica L.) from various locations of Baneh and Marivan regions, Iran. In total, 61 endophytic bacteria were isolated and grouped according to phenotypic properties. Ten selected isolates from each group were further identified by partial sequencing of the 16S rRNA gene. Based on the results, isolates were identified as bacteria belonging to Pseudomonas, Stenotrophomonas, Bacillus, Pantoea and Serratia genus. The ability of these isolates was evaluated to phytohormone production such as auxin and gibberellin, siderophore production, phosphate solubilization, atmospheric nitrogen fixation, protease and hydrogen cyanide production. All strains were able to produce the plant growth hormone auxin and gibberellin in different amounts. The majority of strains were able to solubilize phosphate. The results of atmospheric nitrogen fixation ability, protease and siderophore production were varied among strains. Only Ba66 could produce a low amount of hydrogen cyanide. The results of biocontrol assay showed that Pb78 and Sp15 strains had the highest and lowest inhibition effects on bacterial plant pathogens, Pseudomonas syringae pv. syringae Pss20 and Pseudomonas tolaasii Pt18 under in vitro condition. Pb3, Pb24 and Pb71 strains significantly promote root formation on carrot slices. To our knowledge this is the first report of the isolation of endophytic bacterial strains belonging to Pantoea, Bacillus, Pseudomonas, Serratia and Stenotrophomonas genus from wild pistachio trees with plant growth promoting potential and biocontrol activity. PMID:29887777

Gebruik van TaqMan PCR voor het kwantificeren van Fusarium spp. en Microdochium nivale in gewassen en gewasresten van tarwe

NARCIS (Netherlands)

Köhl, J.; Haas, de B.H.; Kastelein, P.; Burgers, S.L.G.E.; Waalwijk, C.

2005-01-01

Samenvattingen van 5 presentaties: 'Heterogenity of Dutch Fusarium oxysporum strains isolated as forma specialis radicis-lycopersici';'Een proteomics benadering om eiwitten te identificeren die door Fusarium oxysporum worden uitgescheiden in xyleemsap van tomaat'; 'Ontwikkeling en implementatie van

Richtlijnen voor selectie en weergave van residugehaltes van bestrijdingsmiddelen

NARCIS (Netherlands)

van den Velde-Koerts T; van Hoeven-Arentzen PH; Ossendorp BC; CSR

2002-01-01

Residubeoordelingen van bestrijdingsmiddelen worden uitgevoerd om wettelijke residulimieten (MRLs = maximum residue limits) vast te leggen. MRLs worden afgeleid uit de resultaten van die residuproeven met bestrijdingsmiddelen die volgens kritisch "Good Agricultural Practice" zijn

Toepassing van optische sensoren (I). Meting van bellengrootteverdeling in luchtige levensmiddelen.

NARCIS (Netherlands)

Bisperink, C.G.J.; Akkerman, J.C.; Prins, A.

1991-01-01

Beschrijving van een methode, ontwikkeld op het laboratorium voor Zuivel en Levensmiddelennatuurkunde van de LU Wageningen in nauwe samenwerking met de TU Delft, waarmee goed en snel de verdeling van de gasfase in de vloeibare fase in de tijd en op verschillende plaatsen in een monster kan worden

van der Waals

Indian Academy of Sciences (India)

University education was beyond reach for van der Waals as he had to work for earning his daily bread ... languages, which was a prerequisite for entering a University those days. van der Waals worked as a school ... take academic examinations at the University yet, van der Waals continued studying at Leiden. University ...

Het beslissingsproces van de huisarts bij de keuze van een geneesmiddel

NARCIS (Netherlands)

B. Wierenga (Berend); S.J.T. Jong; A. Mantel

1989-01-01

textabstractHet beslissingsproces van de huisarts bij de keuze van een geneesmiddel, zoals het uit dit empirisch onderzoek naar voren kwam, kan als volgt worden getypeerd. In het merendeel van de gevallen (ca. 90%) beperkt de arts zich tot de informatie die hij al in zijn geheugen heeft. Vaak wordt

Vaststellen reproduceerbaarheid van de nachtactiviteit van de Balb/c/rivm muis over de afgelopen vijf jaar

NARCIS (Netherlands)

Steen BVL; Jansen van ' t Land C; CDL

1999-01-01

Om de inschatting van de mate van ongerief onafhankelijk te maken van ervaring en interpretatie van de persoon die de observatie uitvoert, maken wij in onze studies gebruik van een volledig geautomatiseerde opstelling. Met deze geautomatiseerde opstelling kan de bewegingsactiviteit van

Bereiding van gevriesdroogd cholesterolcalibratie en -controleserum ten behoeve van de Stichting Kwaliteitsbewaking Chemische Analyse ten behoeve van Epidemiologisch Onderzoek (KCA)

NARCIS (Netherlands)

Dreumel; H.J.van; Wikkeling; R.H.; Steentjes; G.M.; Buitenhuis; S.G.; Koedam; J.C.

1986-01-01

In het kader van de samenwerking tussen het RIVM en de Stichting KCA (Kwaliteitsbewaking Chemische Analyse t.b.v. Epidemiologisch Onderzoek) werden drie partijen cholesterolserum bereid. Uitgegaan werd van menselijk serum (Centraal Laboratorium van de Bloedtransfusiedienst). Door uit een deel

"Hot Tub Rash" and "Swimmer's Ear" (Pseudomonas)

Science.gov (United States)

Facts About “Hot Tub Rash” and “Swimmer’s Ear” (Pseudomonas) What is Pseudomonas and how can it affect me? Pseudomonas (sue-doh- ... a major cause of infections commonly known as “hot tub rash” and “swimmer’s ear.” This germ is ...

De auteursrechtelijke groeipijnen van Google

NARCIS (Netherlands)

Hugenholtz, P.B.

2011-01-01

Het succesverhaal van Google behoort tot de canon van de geschiedenis van onze informatiemaatschappij. In 1998 begonnen in een studentenkamer op de campus van Stanford University, groeide Google in enkele jaren uit tot het orakel van het internet. Zo werd ‘googelen’ de gebruikelijke term voor zoeken

Beoordeling van de gevoeligheid van soorten en habitattypes van Europees belang bij verstoringingrepen

OpenAIRE

Wouters, Jan

2011-01-01

Om ecologische schade te vermijden, moeten activiteiten of plannen met mogelijk schadelijke effecten doorgelicht worden. Het instrument ‘effectenindicator’ licht activiteiten in algemene termen door op mogelijke natuureffecten. De in dit advies weergegeven gevoeligheidstabellen geven de gevoeligheid op van soorten en biotopen voor effecten ten gevolge van menselijke activiteiten. De tabellen bevatten deze gegevens voor de soorten waarvoor gewestelijke instandhoudingsdoelstellingen zijn opgest...

De consequenties van categorieën: een analyse van grensoverschrijdende genre-identiteit in de populaire muziek

NARCIS (Netherlands)

van Venrooij, A.; Schmutz, V.

2013-01-01

Op basis van een analyse van de genreclassificaties door recensenten van 2951 popmuziekalbums worden in dit paper de consequenties onderzocht van het bezitten van een fuzzy of grensoverschrijdende genre-identiteit op het vergaren van commercieel en kritisch succes. De resultaten bevestigen in grote

Advies voor de toepassing van ground-penetrating radar bij de inventarisatie van de grondwaterdynamiek

NARCIS (Netherlands)

Knotters, M.

2001-01-01

Ground-penetrating radar (GPR) biedt mogelijk een nauwkeurig alternatief voor arbeidsintensieve metingen van de grondwaterstand in boorgaten. De GPR-metingen kunnen als hulpinformatie dienen bij geostatistische interpolatie van grondwaterstanden. Op basis van literatuurstudie en verkenning van het

Vrouekarakters in enkele prosawerke van C.M. van den Heever

Directory of Open Access Journals (Sweden)

E. Botha

2003-08-01

Full Text Available The role of women in some prose works of C.M. van den Heever Re-reading the C.M. van den Heever “classics” Somer (1935 and Laat vrugte (1939 within the framework of Van den Heever criticism through the years, one becomes aware that central themes in his oeuvre are acted out by women. The beautiful young girl Linda in Somer embodies the sadness of the transcience of beauty and happiness. Through Ouma Willa, Betta and Johanna – three women from three generations in Laat vrugte – the theme of the endurance of the memory of love and passion beyond decay and death is expressed. A cursory examination of other and earlier works by Van den Heever – Op die plaas (1927, Langs die grootpad (1928, Kromburg (1937 and the short story “Leuens” (Lies from Vuurvlieg en sterre (1934 – bears out the observation that women express core meanings in C.M. van den Heever’s prose works.

Tranen van bloed : Het beleg van 's-Hertogenbosch en de oorlog in de Nederlanden, 1629

NARCIS (Netherlands)

Cauwer, de Peter

2008-01-01

Het beleg van 's-Hertogenbosch en de veldtocht van 1629 staat in de Nederlandse geschiedschrijving te boek als een van de meest roemruchte gebeurtenissen van de Tachtigjarige Oorlog. Het beeld en de interpretaties van deze gebeurtenis zijn de afgelopen decennia nauwelijks veranderd. Toch bleven de

Onderdeel: Kwaliteit van uitleg, deel uitmakend van het onderzoek naar: Corporate governance in Nederland

NARCIS (Netherlands)

Schutte-Veenstra, J.N.; Boschma, H.E.

2011-01-01

De wijze en mate van naleving en toepasing van de principes en best practices van de nederlandse corporate governance code door de Nederlandse beursgenoteede vennootschappen in ht boekjaar 2010, alsmede de redengeving van eventuele afwijkingen, d.d. 21 september 2011.

Groei van ongelijkjarige mengingen van grove den en berk op arme zandgronden; resultaten van metingen in 22 opstanden op de Veluwe en de Sallandse Heuvelrug

NARCIS (Netherlands)

Wijdeven, S.M.J.; Oosterbaan, A.; Berg, v.d. C.; Jole, van M.

2000-01-01

Het voorkomen en de groei van berk in ongelijkjarige mengingen van grove den en berk is bepaald op basis van opstandgemiddelden. Er is geen duidelijk verband tussen het voorkomen en de groei van berk en de schermdichtheid van grove den. Actuele groeigegevens zijn noodzakelijk voor een nadere

Die meting van die invloed van organisasiegrootte op bruin werkers se houdings en gedrag

Directory of Open Access Journals (Sweden)

R. van der Bank

1985-11-01

'n Oorsig van die literatuur dui daarop dat bevindinge onkonsekwent is wat betref die invloed van die grootte van organisasies op veranderlikes soos die doeltreffendheid van personeel-keuringstelsels, opleiding, arbeidsomset, werkafwesigheid, werkdoeltreffendheid en so meer. In Wes-Kaapland is tien "groot" fabrieke geselekteer (aantal bruin werkers 300 of meer en vergelyk met 17 "klein" fabrieke (aantal bruin werkers minder as 50. Met behulp van t-toetse is statisties beduidende verskille gevind ten opsigte van die volgende veranderlikes waarvolgens groot organisasies meer gunstig vertoon: 1 meer keuringstegnieke word gebruik; 2 die doeltreffendheid van die keurings-programme is hoër; 3 meer opleidingstegnieke word gebruik; 4 opleidingsprogramme is meer doeltreffend; 5 werkers is meer tevrede; 6 werkers se gemiddelde beroepsaanpassing is beter, en 7 werkers is meer tevrede met hul salarisse of lone. Geen betekenisvolle verskille is egter gevind ten opsigte van arbeidsomset, werkafwesigheid en werkbehoeftes nie.

OXIDATION OF POLYCHLORINATED BIPHENYLS BY PSEUDOMONAS SP. STRAIN LB400 AND PSEUDOMONAS PSEUDOALCALIGENES KF707

Science.gov (United States)

Biphenyl-grown cells and cell extracts prepared from biphenyl-grown cells of Pseudomonas sp. strain LB400 oxidize a much wider range of chlorinated biphenyls than do analogous preparations from Pseudomonas pseudoalcaligenes KF707. These results are attributed to differences in th...

09 Van Coller 03.pmd

African Journals Online (AJOL)

Owner

29 Jul 2010 ... strangeness, awakening in it a drama whose actors are all those assumptions and operations which make the text the work of another period”. Die spore van Raka: Oor herskrywing en kanonisering. (Deel 2). H.P. van Coller en A. van Jaarsveld. H. P. van Coller is hoof van die Departement. Afrikaans ...

Het dichtwerk van Jan van Foreest (1585-1651)

NARCIS (Netherlands)

Vries, M. de

2007-01-01

The dissertation consists of an edition of Jan van Foreest's Greek poems and the greater part of those written in Latin, provided with translations and a succinct commentary in Dutch. A number of the Latin poems appears in print for the first time ever. Jan van Foreest (1586-1651) studied arts at

CXCR1 regulates pulmonary anti-Pseudomonas host defense

Science.gov (United States)

Carevic, M.; Öz, H.; Fuchs, K.; Laval, J.; Schroth, C.; Frey, N.; Hector, A.; Bilich, T.; Haug, M.; Schmidt, A.; Autenrieth, S. E.; Bucher, K.; Beer-Hammer, S.; Gaggar, A.; Kneilling, M.; Benarafa, C.; Gao, J.; Murphy, P.; Schwarz, S.; Moepps, B.; Hartl, D.

2016-01-01

Pseudomonas aeruginosa is a key opportunistic pathogen causing disease in cystic fibrosis (CF) and other lung diseases such as chronic obstructive pulmonary disease (COPD). However, the pulmonary host defense mechanisms regulating anti-Pseudomonas aeruginosa immunity remain incompletely understood. Here we demonstrate, by studying an airway Pseudomonas aeruginosa infection model, in vivo bioluminescence imaging, neutrophil effector responses and human airway samples, that the chemokine receptor CXCR1 regulates pulmonary host defense against Pseudomonas aeruginosa. Mechanistically, CXCR1 regulated anti-Pseudomonas neutrophil responses through modulation of reactive oxygen species and interference with toll-like receptor 5 expression. These studies define CXCR1 as a novel non-canonical chemokine receptor that regulates pulmonary anti-Pseudomonas host defense with broad implications for CF, COPD and other infectious lung diseases. PMID:26950764

De miskenning van Theo van Doesburg; zijn bijdrage tot de ontwikkeling van de konkrete poëzie

Directory of Open Access Journals (Sweden)

J. van der Elst

1987-05-01

Full Text Available More literary critics outside Belgium and the Netherlands have written about Theo van Doesburg than from inside these countries. The first important monograph on him appeared in English - Theo van Doesburg - Propagandist and Practitioner of the Avant-Garde, 1909-1923, by Hannah Hedrick. Van Doesburg’s poetry developed in the direction of concrete poetry - the type of poetry in which the spatial, acoustic and visual characteristics of language are maximally utilized towards the creation of the poem. Word as sound and as image is foregrounded in concrete poetry, while the imaging of persons and subjective experience is eliminated as far as possible. The anecdotal or the epic component of the concrete poem is minimal and the language of this sort of poem has been reduced to the minimum. In the spirit of the theory of concrete poetry Van Doesburg advocates the liberation of art from all the commitments imposed upon it. That with which Van Doesburg began was continued by other poets, especially in Germanic literature by poets of the so-called neo-realism.

Effect minerale samenstelling van bodem en plant op de expressie van bladnecrose bij Freesia

NARCIS (Netherlands)

Doorduin, J.C.; Bos, van den A.L.

2003-01-01

Freesiatelers veronderstellen een relatie tussen de voedingstoestand in de grond, de minerale samenstelling van de plant en de expressie van bladnecrose bij freesia. Op verzoek van de Landelijke Freesiacommissie van LTO is een inventarisatie uitgevoerd op ‘gezonde’ en ‘necrose’ bedrijven naar de

Lysine analoga; bereiding en enzymatische hydrolyse van peptide derivaten van lysine en lysine analoga

NARCIS (Netherlands)

Tesser, Godefridus Ignatius

1961-01-01

De synthese van enkele structuuranaloga van lysine wordt beschreven. Aangetoond wordt dat zij lysine in substraten voor trypsine, cathepsine B en papaine kan vervangen. Daar de structuur van de analoga O-(Beta-aminoaethyl)serine en S-(Beta-aminoaethyl) cysteine die van lysine dicht nadert, wordt

Verspreiding en habitats van Bulinus tropicus, tussengasheerslak van die peervormige bot Calicophoron microbothrium, in Suid-Afrika

Directory of Open Access Journals (Sweden)

K. N. de Kock

2002-09-01

Full Text Available Hierdie artikel fokus op die geografiese verspreiding en habitats van Bulinus tropicus, die slaktussengasheer van die peervormige bot, Calicophoron microbothrium. Bulinus tropicus is die varswaterslakspesie met verreweg die wydste geografiese verspreiding, soos gereflekteer deur die vindplekke van die 7 992 monsters wat tans in die databasis van die Nasionale Varswaterslakversameling (NVV van Suid-Afrika op rekord is. Die voorkoms van hierdie spesie is deur versamelaars in ’n totaal van 14 waterliggaamtipes opgeteken, maar die grootste getal monsters is in damme en spruite en in habitats waarvan die water as staande, helder en vars beskryf is, versamel. Die effekgrootte van elke veranderlike is afsonderlik bereken om die rol daarvan in die bepaling van die verspreiding van hierdie spesie vas te stel. Die data in die databasis is verder verwerk en aangepas om ’n geïntegreerde besluitnemingsboom saam te stel. Dit is ’n statistiese model waarvolgens ’n seleksie van veranderlikes gemaak kan word wat maksimaal kan diskrimineer tussen die voorkomsfrekwensie van ’n gegewe spesie en die res van die spesies in die databasis. Die sukses van B. tropicus soos gereflekteer deur sy omvangryke geografiese verspreiding, is waarskynlik toe te skryf aan die omstandigheid dat hierdie spesie grootliks r-geselekteerd is soos onteenseglik in bevolkingsdinamikastudies deur verskeie outeurs bevind is. Daarbenewens beskik die spesie oor’n besondere vermoë om opdroging van ’n habitat vir relatief lang tydperke te kan oorleef. Dit kom egter voor asof sy beperkte verdraagsaamheid ten opsigte van water met ’n relatief lae geleidingsvermoë, moontlik as ’n beperkende faktor vir sy besetting van bepaalde gebiede in Suid-Afrika mag optree. As tussengasheer vir C. microbothrium, wat paramphistomose by vee veroorsaak en soms tot groot verliese kan lei, het die wye verspreiding van B. tropicus in Suid-Afrika egter ook ekonomiese implikasies, veral vir inwoners

Inventarisatie van mogelijke effecten van kribverlaging in de Waal op de beroepsvisserij

NARCIS (Netherlands)

Winter, H.V.

2011-01-01

Om de hoogwaterveiligheid van het rivierengebied te vergroten is het doel van Rijkswaterstaat om eind 2015 ca. 500 kribben in de Waal verlaagd te hebben en daarnaast langsdammen aangelegd te hebben tussen Wamel en Ophemert. In deze korte deskstudie wordt een inventarisatie gemaakt van mogelijke

Beheersing en bestrijding van Botrytis cinerea en van Penicillium in Euphorbia fulgens

NARCIS (Netherlands)

Wubben, J.P.; Hazendonk, A.; Bosker, I.; Slootweg, C.; Hoope, ten M.

2002-01-01

De bloeiwijze van Euphorbia fulgens kent twee belangrijke schimmelbelagers, die problemen in de teelt veroorzaken: Botrytis cinerea en Penicillium. B. cinerea geeft schade in de vorm van smet of pokken, die op de bloemblaadjes verschijnen. Dit zijn kleine donkerbruine/zwarte plekjes van ongeveer 1

Modellering van begrazing in SUMO : verbetering van de vegetatiemodellering in de Natuurplanner

NARCIS (Netherlands)

Wamelink, G.W.W.; Wegman, R.M.A.; Slim, P.A.; Dirksen, J.; Mol-Dijkstra, J.P.; Dobben, van H.F.

2001-01-01

In samenwerking met het RIVM en WU wordt het vegetatievoorspellingsmodel SUMO ontwikkeld. Het model vormt een integraal onderdeel met SMART en wordt onder andere gebruikt in de natuurplanner van het RIVM. Om de modellering van de effecten van begrazing op de vegetatieontwikkeling en successie

Kwaliteitsdocument inzake de bepaling van Cadmium in kunststoffen met behulp van Rontgenflurescentie

NARCIS (Netherlands)

Hoogerbrugge R; van de Wiel HJ; van de Beek ACW; Kliest JJG; IEM

1999-01-01

Bij de handhaving van het besluit Cadmium in Kunststoffen is gebleken, dat de analyse met behulp van Rvntgenfluorescentie (XRF) een snel en goedkoop alternatief zou kunnen zijn voor de op dit moment wettelijk voorgeschreven methoden. In opdracht van de Inspecteur Milieuhygikne is daarom door het

De morbiditeit van astma en COPD in Nederland; een inventariserend onderzoek ten behoeve van de beleidsondersteuning van het Nederlands Astma Fonds

NARCIS (Netherlands)

Smit HA; Beaumont M; CZE

2000-01-01

In opdracht van het Nederlands Astma Fonds is een inventarisatie gemaakt van beschikbare kennis over de morbiditeit van astma en COPD in Nederland. De volgende vraagstellingen werden geformuleerd: Inventarisatie: welke gegevensbronnen zijn beschikbaar, welke gegevens zijn daarin aanwezig? In

’n Evaluering van die welstand onder werknemers van ’n mediesefondsmaatskappy in Suid-Afrika

Directory of Open Access Journals (Sweden)

Lee-Anne Naicker

2015-02-01

Full Text Available Huidige navorsing op die gebied van welstand in die werkplek is gefragmenteer en vereis ’n holistiese, geïntegreerde en stelselmatige begrip van werknemerwelstand sodat gesondheiden welstandsorg doeltreffend bestuur kan word. Die toenemende las van nie-oordraagbare toestande in Suid-Afrika beklemtoon die noodsaaklikheid van voorkomingstrategieë soos welstandprogramme. Die werkomgewing bied ’n ideale plek, aangesien ’n groot deel van die bevolking geteiken word, insluitende diegene wie se lewenstyl verbeter moet word. Hierdie studie is dus daarop gemik om verskeie gesondheid- en welstandkomponente onder werknemers van ’n mediesefondsmaatskappy te evalueer in ’n poging om risikogebiede te identifiseer wat verdere ingryping vereis. Die deelnemers het bestaan uit 140 werknemers van ’n mediesefondsmaatskappy wat ten minste 40 h per week werk. Hulle is onderwerp aan ’n welstandassesseringsbattery bestaande uit antropometrieke, gesondheidverwante en fisieke kapasiteitmetings. Die resultate toon dat ingryping nodig is betreffende alkohol- en dwelmgebruik, dieetgewoontes, hartgesondheid, liggaamsamestelling, spieruithouvermoë, kardiorespiratoriese uithouvermoë en individuele persepsies van die maatskappy. Dié studie het resultate opgelewer wat die bevindings van baie vorige navorsing op hierdie gebied staaf. Die trefwydte van welstandprogramme op die Suid-Afrikaanse bevolking is egter beperk. Die sukses van welstandprogramme wat fisieke aktiwiteit beklemtoon, is goed gedokumenteer in hoë-inkomstelande, met bewys van die ekonomiese voordele en opbrengs op belegging. Gevolglik word daar aangevoer dat die toepassing van welstandprogramme ’n positiewe uitwerking op die Suid-Afrikaanse werkmag sal hê.

Praktijkkennis van leerkrachten als ontwerpers van een ICT rijke leeromgeving

NARCIS (Netherlands)

Boschman, Ferry; McKenney, Susan; Voogt, Joke

2011-01-01

Ormel, B., Pareja, N., & McKenney, S. (2011, 8-10 June). Praktijkkennis van leerkrachten als ontwerpers van een ICT rijke leeromgeving. Presentation at the ORD annual meeting, Maastricht, The Netherlands.

Mogelijkheden tot productie van beertjes

NARCIS (Netherlands)

Scholten, R.; Huiskes, J.

1994-01-01

In opdracht van het Produktschap Vee en Vlees is het project Mogelijkheden tot productie van vleesbeertjes en afzet van vlees en vleesproducten hiervan uitgevoerd. De afzetmogelijkheden voor vlees van beertjes zijn en blijven vooralsnog minimaal

2012, 11/01807, (Vrijstellingsmethode niet van toepassing op Amerikaans deel van bestuurdersbeloning)

NARCIS (Netherlands)

D. Molenaar (Dick)

2012-01-01

textabstractSamenvatting: Belanghebbende is met ingang van 1 februari 2004 werkzaam als CEO bij C en vanaf 31 december 2003 als statutair bestuurder van de Amerikaanse werkmaatschappij van C. Eind 2004 heeft belanghebbende een additioneel belang in C verworven. Het verschil tussen de waarde in het

Van graf tot wieg ; de rol van fintech door de generaties heen

NARCIS (Netherlands)

Vries, A. de; Bakas, A.

2015-01-01

Als financiële dienstverlener moet je rekening houden met mensen van alle leeftijden en uit alle lagen van de bevolking. Van de hulpbehoevende senior tot de nieuwsgierige kleuter. We vroegen 2 experts wat verschillende levensfasen typeert, hoe deze persona’s tegen technologie aankijken en hoe

De fysica van polymere materialen

NARCIS (Netherlands)

Struik, L.C.E.

1987-01-01

Rede, uitgesproken ter gelegenheid van de aanvaarding van het ambt van buitengewoon hoogleraar in de fysica van polymere materialen aan de Universitelt Twente op donderdag 22 januarì 1987 door Dr.lr. L.C.E. Struik.

Inhibition of Pseudomonas aeruginosa elastase and Pseudomonas keratitis using a thiol-based peptide.

OpenAIRE

Burns, F R; Paterson, C A; Gray, R D; Wells, J T

1990-01-01

Pseudomonas aeruginosa elastase is a zinc metalloproteinase which is released during P. aeruginosa infections. Pseudomonas keratitis, which occurs following contact lens-induced corneal trauma, can lead to rapid, liquefactive necrosis of the cornea. This destruction has been attributed to the release of both host-derived enzymes and the bacterial products P. aeruginosa elastase, alkaline protease, exotoxin A, and lipopolysaccharide endotoxin. A synthetic metalloproteinase inhibitor, HSCH2 (DL...

Die histologie en ultrastruktuur van die hepatopankreas van die bloukurper Oreochromis mossambicus

Directory of Open Access Journals (Sweden)

M. M. Nel

1990-07-01

Full Text Available Die histologie en ultrastruktuur van die hepatopankreas van die bloukurper Oreochromis mossambicus word beskryf. ’n Dun bindweefselkapsel omring die lewer. Die hepatosietrangskikking vertoon as lobules, met die koorde van hepatosiete wat vanaf ’n sentrale vene uitradieer en met mekaar anastomaseer. Indiwiduele lewerlohules vertoon nie duidelike grense nie, maar enkele duidelike triades word wel in die lewer van O. mossambicus aangetref. Die hepatosiete bevat ’n enkele ronde kern met ’n duidelike nukleolus en die growwe endoplasmiese retikula kom in twee of meer rye om die kerne en teen die selgrense van die hepatosiete voor. Die ander sitoplasmiese organelle kom verspreid in die hepatosietsitoplasma voor. Die eksokriene pankreasselle is om die portale venes gesetel. Die kerne van hierdie selle is rond en is hasaal in die kubies- tot silindervormige selle gelee. ’n Goedontwikkelde growwe endoplasmiese retikulum — vesikulêr, tubulêr en sirkulêr in vorm — en sektretoriese granules wat apikaal in die sel gelee is, kom voor.

Quick change: post-transcriptional regulation in Pseudomonas.

Science.gov (United States)

Grenga, Lucia; Little, Richard H; Malone, Jacob G

2017-08-01

Pseudomonas species have evolved dynamic and intricate regulatory networks to fine-tune gene expression, with complex regulation occurring at every stage in the processing of genetic information. This approach enables Pseudomonas to generate precise individual responses to the environment in order to improve their fitness and resource economy. The weak correlations we observe between RNA and protein abundance highlight the significant regulatory contribution of a series of intersecting post-transcriptional pathways, influencing mRNA stability, translational activity and ribosome function, to Pseudomonas environmental responses. This review examines our current understanding of three major post-transcriptional regulatory systems in Pseudomonas spp.; Gac/Rsm, Hfq and RimK, and presents an overview of new research frontiers, emerging genome-wide methodologies, and their potential for the study of global regulatory responses in Pseudomonas. © FEMS 2017.

Verspreiding van zout bij het terugwinnen van zeezand uit een depot in het Haringvliet

NARCIS (Netherlands)

Kranenburg, C.

1991-01-01

Dit rapport geeft een beknopte analyse van de verdunning en verspreiding van zout vanuit een gepland depot voor ontzilt zeezand in het Haringvliet. Beschouwd zijn de initiële menging van het zout bij terugwinnen van het zand, de verspreiding door stroming en turbulentie bij geopende spuisluis, en de

Van strafbaar tot huwbaar : homorecht wereldwijd (presentatie op Ministerie van Buitenlandse Zaken, Den Haag)

NARCIS (Netherlands)

Waaldijk, C.

2015-01-01

Met de door hem ontwikkelde Global Index on Legal Recognition of Homosexual Orientation (GILRHO) geeft Kees Waaldijk op een schaal van nul tot acht aan, hoe ver een land is met het uit het strafrecht halen van homoseksualiteit, met het verbieden van homodiscriminatie en met het erkennen van

Voorkoming en beheersing van gebreksverschijnselen in de bloembollenteelt : teelt en afbroeiproeven met als doel het voorkomen van ijzergebrek bij tulpen, hyacinten en narcissen van mangaangebrek bij tulpen en van vervroegde afsterving bij lelies

NARCIS (Netherlands)

Dam, van A.M.; Dam, van M.F.N.; Bruin, P.N.A.

2004-01-01

Door veranderingen in de teelten en de aanscherping van het overheidsbeleid t.a.v. het gebruik van met name dierlijke mest kunnen zich bij de teelt van bloembollen verschijnselen voordoen die mogelijk samenhangen met een gebreksituatie. PPO heeft in dit project een aantal van deze verschijnselen

Kosten van allogene stamceltransplantaties

NARCIS (Netherlands)

M. van Agthoven (Michel); M.T. Groot (Martijn); C.A. Uyl-de Groot (Carin)

2001-01-01

textabstractAllogene stamceltransplantatie is een topspecialistische procedure die met succes kan worden ingezet in de behandeling van (hematologische) maligniteiten, met name bij leukemie. Van oudsher worden transplantaten van verwante donoren gebruikt, maar met de mogelijkheden om transplantaten

Contra-expertise op bepalingen van radioactiviteit van afvalwater en ventilatielucht van de kernenergiecentrale Borssele. Periode 2008

NARCIS (Netherlands)

Kwakman PJM; Overwater RMW; LSO

2012-01-01

Dit rapport is eerder vertrouwelijk uitgebracht als briefrapport 610330093. Dit is besproken met de VROM-opdrachtgever en vertegenwoordigers van de betreffende nucleaire installatie: het commentaar op het rapport is verwerkt, voorzien van een Rapport in het Kort, en mag openbaar worden als RIVM

Contra-expertise op bepalingen van radioactiviteit van afvalwater en ventilatielucht van de kernenergiecentrale Borssele. Periode 2009

NARCIS (Netherlands)

Kwakman PJM; Overwater RMW; LSO

2012-01-01

Dit rapport is eerder vertrouwelijk uitgebracht als briefrapport 610330103. Dit is besproken met de VROM-opdrachtgever en vertegenwoordigers van de betreffende nucleaire installatie: het commentaar op het rapport is verwerkt, voorzien van een Rapport in het Kort, en mag openbaar worden als RIVM

Contra-expertise op bepalingen van radioactiviteit van afvalwater en ventilatielucht van de kernenergiecentrale Borssele. Periode 2007

NARCIS (Netherlands)

Kwakman PJM; Overwater RMW; LSO

2012-01-01

Dit rapport is eerder vertrouwelijk uitgebracht als briefrapport 610330076. Dit is besproken met de VROM-opdrachtgever en vertegenwoordigers van de betreffende nucleaire installatie: het commentaar op het rapport is verwerkt, voorzien van een Rapport in het Kort, en mag openbaar worden als RIVM

Resultaten van het RWS-RIKZ JAMP 2003 monitoringsprogramma van bot (Platychthys flesus L.). Biologische gegevens van bot en milieukritische stoffen in bot en mosselen

NARCIS (Netherlands)

Kotterman, M.J.J.

2004-01-01

In opdracht van RWS-RIKZ werden door het RIVO werkzaamheden uitgevoerd in het kader van het Joint Assessment and Monitoring Program van de OSPARCOM. De werkzaamheden bestonden uit het verzamelen van monsters bot waarvan biologische parameters werden bepaald. Tevens werden milieukritische stoffen

Resultaten van het RWS-RIKZ JAMP 2004 monitoringsprogramma van bot (Platichthys flesus L.). Biologische gegevens van bot en milieukritische stoffen in bot en mosselen

NARCIS (Netherlands)

Kotterman, M.J.J.

2005-01-01

In opdracht van RWS-RIKZ werden door het RIVO werkzaamheden uitgevoerd in het kader van het Joint Assessment and Monitoring Program van de OSPARCOM. De werkzaamheden bestonden uit het verzamelen van monsters bot waarvan biologische parameters werden bepaald. Tevens werden milieukritische stoffen

‘Op de wijze van Kavafis’: Die voorbeeld van die digter uit Alexandrië

Directory of Open Access Journals (Sweden)

Phil van Schalkwyk

2014-12-01

Full Text Available Die Griekse digter K.P. Kavafis (1863–1933 word wêreldwyd deur lesers sowel as skrywers besonder hoog geag. Hy het nie net van die grootste twintigste-eeuse skrywers beïnvloed nie,maar is vanweë die buitengewone vertaalbaarheid van sy werk ook betreklik sterk teenwoordig in die letterkunde van meer tale as slegs Grieks en Engels. Vir baie – veral gay lesers, skrywers en kunstenaars – besit Kavafis ’n voorbeeldstatus, ten opsigte van die letterkunde sowel asdie lewe. W.H. Auden het beweer dat dit wat Kavafis onderskei, sy stemtoon is, een wat ’n persoon met ’n unieke perspektief op die wêreld openbaar. Hierdie bydrae, wat deel is van ’nnavorsingsprojek oor idiolektiese skrywersidentiteit, is daarop gerig om die onderskeidende kenmerke van Kavafis se werk, sowel in terme van vorm as inhoud, opnuut te ondersoek. Dit word gedoen binne die raamwerk van die breë kritiese diskoers oor Kavafis en met verwysing na enkele manifestasies/voorbeelde van Nederlandse en Afrikaanse kritiese en kreatieweperspektiewe op sy poësie, met die doel om spesifiek lig te werp op die besondere soortwysheid wat in Kavafis se werk oorgedra word.

Stabilisatie en samenstelling van het glycosidenmengsel van Folia digitalis

NARCIS (Netherlands)

Tattje, Derk Hendrik Evert

1952-01-01

Na een korte inleiding wordt een omschrijving van het begrip stabilisatie gegeven en besproken hoe deze stabilisatie, dit is het irreversibel inactiveren van de enzymen, in het algemeen tot stand kan worden gebracht. Tevens wordt nagegaan of ook door verschillende oplosmiddelen reeds bij gewone

Controle van spectrofotometers in ziekenhuislaboratoria

NARCIS (Netherlands)

Ham; W.A.van den; Steentjes; G.M.; Buitenhuis; S.G.; Terlingen; J.B.A.

1985-01-01

In dit rapport worden de resultaten beschreven van een onderzoek dat door twee medewerkers van het Laboratorium voor Klinische Chemie en Hematologie werd ingesteld naar de toestand van 22 fotometers in ziekenhuislaboratoria. Onderzocht werden: - juistheid van de golflengte-instelling - juistheid

Ingredienten voor kwaliteitsborging van modelonderzoek

NARCIS (Netherlands)

Grinsven JJM van; Haan BJ de; Braat LC; MNV; LBG; CIM

1995-01-01

In dit rapport wordt een aanzet gepresenteerd tot harmonisatie van de kwaliteitsborging van modelonderzoek in het RIVM. Het rapport komt voort uit initiatieven van leden van het Intersectoraal Modellen Overleg. Het rapport is in eerste instantie bedoeld voor onderzoekers die modellen

Die meting van sistematiese tydorientasie as 'n sielkundige konstruk van Beroepsgedrag

Directory of Open Access Journals (Sweden)

J. I. De Jager

1985-11-01

Met hierdie navorsing is gepoog om 'n persoonsbeeld van 'n individu met ‘n sistematiese tydoriëntasiestyl saam te stel, en om 'n verfynde instrument vir die meting van sistematiese tydoriëntasie te ontwikkel. Resultate toon dat die vraelys wel 'n bevredigende interne bestendigheid het en ook as ‘n verfynde instrument vir die meting van sistematiese tydoriëntasie beskou kan word.

Ontwikkeling van een protocol voor de transformatie van iris; introductie van resistentie tegen irismozaik viris (IMMV)

NARCIS (Netherlands)

Langeveld, S.A.; Klerk, de G.J.M.

2004-01-01

Twee iris cultivars, Blue Magic en Blue Sail, werden in weefselkweek gebracht en callus werd geïnduceerd. Dit callus werd genetisch gemodificeerd met virusresistentie via de particle gun procedure die eerder voor lelie was ontwikkeld. Van een van de cultivars, Blue Magic, werden getransformeerde

Transcriptome Analysis of Syringa oblata Lindl. Inflorescence Identifies Genes Associated with Pigment Biosynthesis and Scent Metabolism.

Directory of Open Access Journals (Sweden)

Jian Zheng

Full Text Available Syringa oblata Lindl. is a woody ornamental plant with high economic value and characteristics that include early flowering, multiple flower colors, and strong fragrance. Despite a long history of cultivation, the genetics and molecular biology of S. oblata are poorly understood. Transcriptome and expression profiling data are needed to identify genes and to better understand the biological mechanisms of floral pigments and scents in this species. Nine cDNA libraries were obtained from three replicates of three developmental stages: inflorescence with enlarged flower buds not protruded, inflorescence with corolla lobes not displayed, and inflorescence with flowers fully opened and emitting strong fragrance. Using the Illumina RNA-Seq technique, 319,425,972 clean reads were obtained and were assembled into 104,691 final unigenes (average length of 853 bp, 41.75% of which were annotated in the NCBI non-redundant protein database. Among the annotated unigenes, 36,967 were assigned to gene ontology categories and 19,956 were assigned to eukaryoticorthologous groups. Using the Kyoto Encyclopedia of Genes and Genomes pathway database, 12,388 unigenes were sorted into 286 pathways. Based on these transcriptomic data, we obtained a large number of candidate genes that were differentially expressed at different flower stages and that were related to floral pigment biosynthesis and fragrance metabolism. This comprehensive transcriptomic analysis provides fundamental information on the genes and pathways involved in flower secondary metabolism and development in S. oblata, providing a useful database for further research on S. oblata and other plants of genus Syringa.

Plaatsen van beschaafd vertier

Directory of Open Access Journals (Sweden)

James Kennedy

2014-09-01

Full Text Available Plaatsen van beschaafd vertier [Places of civilised amusement] by Jan Hein Furnée, which appeared as a PhD thesis in 2007 and was adapted and extended into a book in 2012, is regarded by historians of the Low Countries as an impressive tour de force. In a stimulating manner Furnée demonstrates with this profound urban history that for the elite of The Hague leisure activities played an important role in acquiring status and maintaining their position. His study is based on extensive and systematic research into a great variety of sources, from census registers, membership lists of clubs and societies to address books. This gives the reader an extraordinarily detailed picture of the changing social relations in the upper echelons of society in The Hague in the latter half of the nineteenth century. The sophisticated use of both qualitative and quantitative methods can serve as a model for other historians in the field of urban history. In a lively fashion Furnée shows that the inhabitants of The Hague grasped at all kinds of pastimes in order to distinguish themselves from others, and when possible to increase their own status through their participation in elegant societies, theatre visits or supporting the proposed zoo: but the book also makes statements about status and class, the history of gender and of politics at the end of the nineteenth century. Plaatsen van beschaafd vertier van Jan Hein Furnée dat in 2007 als proefschrift en in 2012 bewerkt en uitgebreid als boek verscheen, staat onder historici van de Lage Landen bekend als een imponerende tour de force. Op prikkelende wijze laat Furnée in deze diepgravende stadsgeschiedenis zien dat vrijetijdsbesteding voor Haagse elites een belangrijke rol speelde in standsvorming en handhaving van hun positie. Zijn studie is gebaseerd op uitgebreid en systematisch onderzoek van veelsoortige bronnen, van volkstellingsregisters, ledenlijsten van verenigingen en sociëteiten tot adresboeken

Van wie zijn zij? De ambtenaren

NARCIS (Netherlands)

Peters, Jit

2011-01-01

Aan de hand van actuele voorbeelden gaat Jit Peters tijdens zijn afscheidscollege in op de toegenomen macht van ambtenaren. De loyaliteit van de ambtenaar is volgens hem nu te veel gericht op het ondersteunen van de eigen minister. Als tegenwichten van de macht van de ambtenaar staat Peters stil bij

Microbewerking met behulp van lasers

NARCIS (Netherlands)

Ezendam, M.M.M.

1994-01-01

Het bewerken van materialen met behulp van lasers staat momenteel enorm in de belangstelling, en terecht. De ontwikkeling van bestaande en nieuwe typen lasers staat alles behalve stil. Ontwikkelingen bevinden zich met name in het gebied van hogere vermogens, betere bundelkwaliteit en hogere

Thijs van Vugt, Een arbeidersbuurt onder de rook van ‘De Sphinx’. Eeen sociaal-ruimtelijke geschiedenis van het Boschstraatkwartier-Oost te Maastricht, 1829-1904

Directory of Open Access Journals (Sweden)

Christianne Smit

2015-12-01

Full Text Available Thijs van Vugt, Een arbeidersbuurt onder de rook van ‘De Sphinx’. Een sociaal-ruimtelijke geschiedenis van het Boschstraatkwartier-Oost te Maastricht, 1829-1904 (Dissertatie Universiteit van Maastricht 2015; Maaslandse Monografieën 78; Hilversum: Verloren, 2015, 228 pp., isbn 978 90 8704 493 0.

De Smartcard van 2010

NARCIS (Netherlands)

Hartel, Pieter H.; Jacobs, Bart

2001-01-01

Aan de universiteiten van Twente en Nijmegen zijn twee onderzoeksgroepen onder leiding van de auteurs intensief bezig met smartcards. Beide auteurs zijn eerder dit jaar betrokken geweest bij het opstellen van de nieuwe Europese onderzoeksagenda voor smartcards, binnen het zogenaamde zesde kader

Lichtdoorlatendheid van kasdekken onder verschillende omstsndigheden

NARCIS (Netherlands)

Bot, G.P.A.

1984-01-01

Aandacht voor lichtonderschepping; bewolkingsgraad; direkte straling; diffuse straling en gevolgen van veranderingen in kaskonstruktie of materiaaleigenschappen ten aanzien van de lichtdoorlatendheid. Bij vergelijking van de lichttransmissie van diverse kasdekken dient te worden uitgegaan van

Vloeistof-vloeistof verdeling als onderzoekmethode bij de vergelijking van enige rassen van digitalis purpurea L.

NARCIS (Netherlands)

Henning, Gerardus Johannes

1962-01-01

De samenstelling van het glycosidenmengsel van drie rassen van Digitalis purpura L. werd in verschillende groeistadia onderzocht. Door extractie met chloroform van een waterige oplossing der in het gefermenteerde blad voorkomende glycosiden werden deze in twee groepen verdeeld, een in chloroform

Algemene principes van palliatieve zorg

NARCIS (Netherlands)

de Graeff, A; Jobse, A.; Teunissen, SCCM; Verkuijlen, S.; Vissers, K.C.P.; Zylicz, Z; Gilsing, M.

2017-01-01

Palliatieve zorg is een benadering die de kwaliteit van leven verbetert van patiënten (kinderen en volwassenen) en hun naasten die te maken hebben met een levensbedreigende aandoening, door het voorkomen en verlichten van lijden door middel van vroegtijdige signalering en zorgvuldige beoordeling en

Burnout : de stand van zaken

NARCIS (Netherlands)

Taris, T.; Houtman, I.L.D.; Schaufeli, W.

2013-01-01

Dit artikel geeft een overzicht van de stand van zaken in het onderzoek naar burnout. Burnout is een syndroom van extreme vermoeidheid (uitputting), afstand nemen van het werk (distantie) en weinig vertrouwen in het eigen kunnen (verminderde competentie), waarbij de oorzaken voor deze aspecten

Bestrijding van duist in wintertarwe

NARCIS (Netherlands)

Timmer, R.D.

2006-01-01

Duist, en speciaal resistente duist, is één van de grootste problemen in het graantelend gebied het Oldambt. De wintertarwegewassen ondervinden sterke concurrentie van de groeiende duistpopulatie, hetgeen ten koste gaat van de opbrengst. De inzet en kosten van de toegepaste herbiciden nemen toe

Die konteks vir die keuse van geriefsvoedsel van bepaalde ...

African Journals Online (AJOL)

Seugnet

70. Die konteks vir die keuse van geriefsvoedsel van bepaalde beroepsvroue *. Martha Kok en Priscilla Botha. ABSTRACT. The purpose of this research is to understand and describe the context in which career women choose, purchase and use convenience food (CF). A person is rarely isolated from or unaffected by.

Het presteren van FM

NARCIS (Netherlands)

van der Voordt, D.J.M.

2008-01-01

Prestatieafspraken. Prestatiespecificaties. Prestatiecontracten. Het woord prestatie duikt steeds vaker op in de wereld van FM. Maar wat bedoelen we er nu precies mee? En kunnen we de prestaties van FM wel op een betrouwbare en valide manier meten? Een beschouwing vanuit de wereld van een

Enkele hydrologische aspecten van een bodem- en grondwaterverontreiniging op het fabrieksterrein van Nestle te Rotterdam

NARCIS (Netherlands)

Mulschlegel; J.; Kusse; A.A.M.

1984-01-01

De Regionaal Inspecteur van de Volksgezondheid voor de Milieuhygiene voor Zuid-Holland verzocht RIVM-LBG inzicht te geven in de eventuele verbreiding van een verontreiniging op het fabrieksterrein van Nestle te Rotterdam. Bij het uitgevoerde onderzoek is gebruik gemaakt van een 3-dimensionaal

Enhanced annotations and features for comparing thousands of Pseudomonas genomes in the Pseudomonas genome database.

Science.gov (United States)

Winsor, Geoffrey L; Griffiths, Emma J; Lo, Raymond; Dhillon, Bhavjinder K; Shay, Julie A; Brinkman, Fiona S L

2016-01-04

The Pseudomonas Genome Database (http://www.pseudomonas.com) is well known for the application of community-based annotation approaches for producing a high-quality Pseudomonas aeruginosa PAO1 genome annotation, and facilitating whole-genome comparative analyses with other Pseudomonas strains. To aid analysis of potentially thousands of complete and draft genome assemblies, this database and analysis platform was upgraded to integrate curated genome annotations and isolate metadata with enhanced tools for larger scale comparative analysis and visualization. Manually curated gene annotations are supplemented with improved computational analyses that help identify putative drug targets and vaccine candidates or assist with evolutionary studies by identifying orthologs, pathogen-associated genes and genomic islands. The database schema has been updated to integrate isolate metadata that will facilitate more powerful analysis of genomes across datasets in the future. We continue to place an emphasis on providing high-quality updates to gene annotations through regular review of the scientific literature and using community-based approaches including a major new Pseudomonas community initiative for the assignment of high-quality gene ontology terms to genes. As we further expand from thousands of genomes, we plan to provide enhancements that will aid data visualization and analysis arising from whole-genome comparative studies including more pan-genome and population-based approaches. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

21 CFR 866.3415 - Pseudomonas spp. serological reagents.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pseudomonas spp. serological reagents. 866.3415... (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3415 Pseudomonas spp. serological reagents. (a) Identification. Pseudomonas spp. serological reagents are devices that...

Die bantering van daar-interferensie in die Duits van Afrikaansmoedertaliges

Directory of Open Access Journals (Sweden)

Emerencia C. Steyn

2013-02-01

Full Text Available A comparison of sentence constructions in the soundtracks (simulcast of some television programmes indicates a general lack of a German equivalent for the multiple use of the A.frikaans daar. This naturally results in interference in the usage of German by A.frikaans speaking students, as they are inclined to construct their German sentences in accordance with the A.frikaans equivalents. This problem is mainly illustrated in either the erroneous use of a da or an inappropriate es gibt. Various exercises are submitted, aimed at obviating such errors of interference which are mainly noticeable in the spoken ·language. Soos blyk uit 'n vergelyking van segslryses in die parallelle klankbane van enkele televisieprogramme, het die veelvuldige gebruik van die Afrikaanse woord daar gewoonlik geen ekwivalensie in Duits nie. Dit lei maklik tot interferensie in die Duits van Afrikaansmoedertalige studente, omdat hulle daartoe neig om hul Duitse sinne soos die in A.frikaans te konstrueer. Hierdie probleem word hoofsaaklik in die foutiewe gebruik van da geopenbaar; soms egter ook in 'n misplaaste es gibt. Verskeie oefeninge word aan die hand gedoen om sulke interferensiefoute, wat vera! in m(mdelinge werk opduik, te bekamp.

Preventie van slaapgebrek en vermoeidheid

NARCIS (Netherlands)

Simons, R; Valk, P.

2006-01-01

Korte schets van de bijdrage aan het Europese Fit-to Fly project ( Early Warning Systems sensoren) van TNO Defensie en Veiligheid en hun eigen onderzoek naar fase-verschuiving van de slaap en strategisch gedoseerde slaapperioden. De eisen die een missie aan het personeel stelt, de verstoring van het

Teelt van hybride wintertarwerassen

NARCIS (Netherlands)

Timmer, R.D.; Paauw, J.G.M.

2003-01-01

Om de mogelijkheden van de teelt van hybride wintertarwerassen onder Nederlandse omstandigheden in beeld te brengen zijn er van 2000-2002 proeven uitgevoerd op het PPO-proefbedrijf te Lelystad. In deze proeven zijn een 4-tal hybriderassen (Hybnos, Hyno-braba, Hyno-esta, Mercury) vergeleken met een

De keuze van Vincent

NARCIS (Netherlands)

Stolwijk, Chris

2003-01-01

Official publication to accompany the important exhibition Vincent's Choice, Van Gogh's 'musee imaginaire' at the Van Gogh Museum, Amsterdam marking the 150th anniversary of the artist's birth.Thanks to van Gogh's correspondence, it has been possible to identify the works he knew and admired. The

‘Anders slapen’. Evaluatie van ‘anders slapen’: een pilotonderzoek naar het effect van ‘anders slapen’ bij spanningshoofdpijn op Kwaliteit van Leven en participatie.

NARCIS (Netherlands)

de Vlugt, Liesbeth

2014-01-01

Samenvatting Inleiding- (Spannings)hoofdpijn is een veelvoorkomend probleem dat van invloed is op de Kwaliteit van Leven (KvL) en participatie van mensen in het dagelijks leven. Cervicogene hoofdpijn is een vorm van spanningshoofdpijn, waarbij de oorzaak gelegen is in spanning in de nek. Elkhuizen

Dicty_cDB: Contig-U16444-1 [Dicty_cDB

Lifescience Database Archive (English)

Full Text Available 001503 |pid:none) Burkholderia glumae BGR1 chromos... 130 5e-30 AF511570_1( AF511570 |pid:none) Uncultured soil...) Pseudomonas syringae pv. phaseo... 80 2e-13 AF511571_1( AF511571 |pid:none) Uncultured soil bacterium clon...00390 |pid:none) Mesorhizobium sp. BNC1, complete... 57 3e-09 AF511572_1( AF511572 |pid:none) Uncultured soil

Genetic Detection of Pseudomonas spp. in Commercial Amazonian Fish

Science.gov (United States)

Ardura, Alba; Linde, Ana R.; Garcia-Vazquez, Eva

2013-01-01

Brazilian freshwater fish caught from large drainages like the River Amazon represent a million ton market in expansion, which is of enormous importance for export to other continents as exotic seafood. A guarantee of bacteriological safety is required for international exports that comprise a set of different bacteria but not any Pseudomonas. However, diarrhoea, infections and even septicaemia caused by some Pseudomonas species have been reported, especially in immune-depressed patients. In this work we have employed PCR-based methodology for identifying Pseudomonas species in commercial fish caught from two different areas within the Amazon basin. Most fish caught from the downstream tributary River Tapajòs were contaminated by five different Pseudomonas species. All fish samples obtained from the River Negro tributary (Manaus markets) contained Pseudomonas, but a less diverse community with only two species. The most dangerous Pseudomonas species for human health, P. aeruginosa, was not found and consumption of these fish (from their Pseudomonas content) can be considered safe for healthy consumers. As a precautionary approach we suggest considering Pseudomonas in routine bacteriological surveys of imported seafood. PMID:24065035

Ontwikkeling en validatie van computer vision technologie ten behoeve van een broccoli oogstrobot

NARCIS (Netherlands)

Blok, Pieter M.; Tielen, Antonius P.M.

2018-01-01

De selectieve en handmatige oogst van broccoli is arbeidsintensief en omvat ongeveer 35% van de totale productiekosten. Dit onderzoek is uitgevoerd om te bepalen of computer vision kan worden gebruikt om broccoli kronen te detecteren, als eerste stap in de ontwikkeling van een autonome selectieve

Bachelorenquêtes 2013. Verslag van de bevindingen van recent afgestudeerden over hun opleiding

NARCIS (Netherlands)

Nielissen, Gé; Münstermann, Henk; Van den Munckhof, Rieny; Schlusmans, Kathleen

2018-01-01

De OU heeft vanaf haar oprichting veel aandacht besteed aan de kwaliteit en innovatie van het onderwijs. Medewerkers van de OU zijn gericht op vernieuwing en verbetering van het onderwijs, wat tot uitdrukking komt in de vele vernieuwingsinitiatieven die de afgelopen jaren hebben plaatsgevonden. De

Siektes van peroksisome - 'n oorsig

African Journals Online (AJOL)

(x 14 SOO). Peroksisoomsiektes2. ,3,5.6. Ongeveer 12 genetiese siektes wat as gevolg van foute in die ontwikkeling of in die samestelling van peroksisome antstaan, is reeds beskryf. Volgens die omvang van die biogenetiese fout en die graad van verlies aan peroksisoomfunksies word hierdie sindrome in 3 groepe.

Implementatie van EU-handhavingsvoorschriften

NARCIS (Netherlands)

Adriaanse, P.C.; Barkhuysen, T.; Boswijk, P.; Habib, K.; Kruif, C. de; Luchtman, M.J.J.P.; Ouden, W. den; Prechal, A.; Steunenberg, B.; Vervaele, J.A.E.; Voermans, W.J.M.; Vries, S.A. de; Widdershoven, R.J.G.M.

2008-01-01

Na een verkennend onderzoek op twaalf beleidsterreinen naar aard, wijze en variatie van de EU/EG-beïnvloeding van nationale handhaving, zijn aan de hand van ‘beïnvloedingsscores’ acht beleidsterreinen geselecteerd voor nadere analyse. In het onderzoek staan de volgende vragen centraal:Hoe is de

Prestatiemeting ten tijde van economische crisis: de aanpak van DSM

NARCIS (Netherlands)

van Rinsum, M.; den Dekker, R.; Maas, V.

2011-01-01

Deze studie besteedt aandacht aan de gevolgen van de financiële crisis voor het prestatiemeetsysteem van een onderneming. Vanwege de financiële crisis hebben veel ondernemingen naast langetermijndoelstellingen ook een aantal kortetermijndoelstellingen geformuleerd die betrekking hebben op hun

Invloed van waterconditioners en hulpstoffen op de effectiviteit van gewasbeschermingsmiddelen

NARCIS (Netherlands)

Zeeland, van M.G.

2007-01-01

In 2005 heeft de gebruikerscommissie naar aanleiding van de literatuurstudie over hulpstoffen drie aanbevelingen voor verder onderzoek geformuleerd. In 2006 zijn twee daarvan in onderzoek genomen, namelijk: wordt door toevoegen van waterconditioners (Easi-mix, Intake, X-change) aan hard water de

Opname van nicotine door kippen en overdracht naar eieren bij toepassing van nicotine tegen bloedluis

NARCIS (Netherlands)

Traag, W.A.; Rijk, de T.C.; Zomer, P.; Vos Van Avezathe, A.; Kan, C.A.; Zeilmaker, M.; Hoogenboom, L.A.P.

2005-01-01

Uit onderzoek van de AID blijkt nicotine gebruikt te worden voor de bestrijding van bloedluis bij kippen. Dit levert mogelijk gezondheidsrisico's op voor de consument van het kippenvlees of de eieren. Omdat niet duidelijk is of het nicotine na de bestrijding van bloedluis in het vlees of eieren

De syntaxis van de Italiaanse preposities

NARCIS (Netherlands)

Boer, M.G. de

2010-01-01

SAMENVATTING In dit hoofdstuk wordt een inventaris opgesteld van de Italiaanse preposities die voorkomen in een corpus bestaande uit de romans La Ciociara van Moravia en Il Gattopardo van Tomasi di Lampedusa. Achtergrond voor de herkenning van preposities is de Extended Standard Theory van de

Die skrifbeskouing van feministiese teoloë, in die besonder dié van Fiorenza, Brenner en Van Dijk-Hemmes – beoordeel in die lig van die gereformeerde teologie

Directory of Open Access Journals (Sweden)

Alta E. Swart

2013-10-01

Full Text Available Dit wil voorkom asof die feministiese Skrifbeskouing op die beginsel van selektiewe Skrifgesag berus. Dit beteken dat slegs dié dele in die Bybel wat met die feministiese ideologie ooreenstem, as gesaghebbend aanvaar word. Dit is veral die sogenaamde androsentriese taalgebruik wat dit vir aanhangers van hierdie benadering moeilik maak om die hele Skrif as gesaghebbend te erken. Hermeneuties vertoon hierdie benadering groot ooreenkomste met die Postmodernisme, waarin geen vaste reëls bestaan om die betekenis van tekste te bepaal nie. Gesien in die lig van die gereformeerde teologie, soos veranker in die Woord en belydenisskrifte, vertoon die feministiese teologie ernstige leemtes. Die bydraes (Skrifbeskouing van drie prominente feministiese teoloë – Fiorenza, Brenner en Van Dijk-Hemmes – word onder die loep geneem en teologies-krities geëvalueer ten einde hierdie leemtes uit te wys. It appears that the feminist view of Scripture is based on the principle of selective authority of the Scriptures, which means that only the parts of the Bible corresponding with the feminist ideology are accepted as authoritative. The use of androcentric language, in particular, makes it difficult for followers of feminism to accept the whole Bible as authoritative. Hermeneutically, their approach resembles Postmodernism, interpreting without any rules. Viewed from the paradigm of the reformed theology, which is anchored in Scripture and the articles of faith, feminist theology shows serious shortfalls. The contributions of three prominent feminist theologians – Fiorenza, Brenner and Van Dijk-Hemmes – are studied closely and evaluated critically in the light of the reformed theology, to underline these shortfalls.

Onderzoek naar het voorkomen van vijf sulfonamiden en Dapson in nieren van Nederlandse slachtvarkens

OpenAIRE

Vaessen HAMG; Kamp CG van de

1987-01-01

Onderzocht zijn 208 monsters varkensnier op voorkomen (HPTLC) en gehalte (HPLC) van sulfanilamide, sulfadimidine, sulfadoxine, sulfadiazine, sulfaquinoxaline en Dapson. De monsters waren afkomstig van slachthuizen gelegen in de zes veterinaire Inspectiegebieden. Uit het HPTLC onderzoek op voorkomen kwamen 8 monsters die kwantitatief werden onderzocht m.b.v. HPLC. Drie monsters bleken < 0,02 mg/kg sulfadimidine te bevatten, het sulfadimidinegehalte van de vijf andere monsters varieerde van ...

Characterization of para-Nitrophenol-Degrading Bacterial Communities in River Water by Using Functional Markers and Stable Isotope Probing.

Science.gov (United States)

Kowalczyk, Agnieszka; Eyice, Özge; Schäfer, Hendrik; Price, Oliver R; Finnegan, Christopher J; van Egmond, Roger A; Shaw, Liz J; Barrett, Glyn; Bending, Gary D

2015-10-01

Microbial degradation is a major determinant of the fate of pollutants in the environment. para-Nitrophenol (PNP) is an EPA-listed priority pollutant with a wide environmental distribution, but little is known about the microorganisms that degrade it in the environment. We studied the diversity of active PNP-degrading bacterial populations in river water using a novel functional marker approach coupled with [(13)C6]PNP stable isotope probing (SIP). Culturing together with culture-independent terminal restriction fragment length polymorphism analysis of 16S rRNA gene amplicons identified Pseudomonas syringae to be the major driver of PNP degradation in river water microcosms. This was confirmed by SIP-pyrosequencing of amplified 16S rRNA. Similarly, functional gene analysis showed that degradation followed the Gram-negative bacterial pathway and involved pnpA from Pseudomonas spp. However, analysis of maleylacetate reductase (encoded by mar), an enzyme common to late stages of both Gram-negative and Gram-positive bacterial PNP degradation pathways, identified a diverse assemblage of bacteria associated with PNP degradation, suggesting that mar has limited use as a specific marker of PNP biodegradation. Both the pnpA and mar genes were detected in a PNP-degrading isolate, P. syringae AKHD2, which was isolated from river water. Our results suggest that PNP-degrading cultures of Pseudomonas spp. are representative of environmental PNP-degrading populations. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

De geschiedenis van de keppel : van Borsalino hoed tot Spiderman keppel

NARCIS (Netherlands)

Ottenheijm, H.L.M.|info:eu-repo/dai/nl/164045775

2017-01-01

Keppels zijn er in alle soorten en maten. Na de Tweede Wereldoorlog werden ze hét symbool van het jodendom. Religiewetenschapper Eric Ottenheijm beschrijft de ontwikkelingen van de joodse hoofdbedekking.

De invloed van bodemreiniging op de biologische beschikbaarheid van metalen

NARCIS (Netherlands)

Adema DMM*; Boer JLM de; Gestel CAM van; Jong P de*

1987-01-01

Er werd onderzoek uitgevoerd met als doel het uitlooggedrag en de biologische beschikbaarheid van metalen in verontreinigde gronden voor en na reiniging te bepalen. Dit (deel)rapport beschrijft de resultaten van het onderzoek naar de biologische beschikbaarheid. Op zes locaties in Nederland

Hoge resolutie typering van Coxiella burnetii

NARCIS (Netherlands)

Janse, I.; Bossers, A.; Roest, H.I.J.; Rotterdam, van B.

2011-01-01

Dit rapport beschrijft het onderzoek wat uitgevoerd is in het kader van het project ‘Hoge Resolutie Typering Coxiella burnetii’’. Het doel van dit project was om de genoomsequenties van een aantal Nederlandse isolaten van de bacterie Coxiella burnetii, de veroorzaker van Q-koorts, in kaart te

Studentopinie als onderdeel van Cursuskwaliteit : Quickscan

NARCIS (Netherlands)

Elzinga, Hanny; Groenewoud, Jan; Ike, Paul; Loth, Betram; Reitsma, Sieuwke; Schotanus, Janke; Schuurman, Mieke; Steur, Jessica

2015-01-01

In het kader van dit onderzoek is een quickscan (15 vragen) opgesteld met als doel die informatie te verzamelen die nodig is om een eerste indicatie te krijgen van de kwaliteit van een cursus (vak). De quickscan is gebaseerd op literatuuronderzoek en best practices van de faculteiten van de

Bepaling van 14C in afvalwater

NARCIS (Netherlands)

Hiemstra YS; Kwakman PJM; Nissan LN; Aldenkamp FJ; LSO

1998-01-01

In opdracht van de Hoofdinspectie Milieuhygiene van het ministerie van VROM heeft LSO een methode ontwikkeld om 14C in afvalwater van nucleaire installaties te bepalen. De methode meet organisch gebonden-14C en anorganisch-14C in de vorm van carbonaat (14CO32-) in afvalwater. Het rapport

Per maand of per kWh?: beoordeling van de effecten van een ander tariefsysteem voor kleinverbruikers electriciteit

NARCIS (Netherlands)

Aalbers, R.F.A.; de Nooij, M.

2006-01-01

Dit rapport bepaalt de effecten van de invoering van een capaciteitstarief voor de kosten van het transport van elektriciteit voor kleinverbruikers. Centraal kenmerk van een capaciteitstarief is dat kleinverbruikers niet langer per afgenomen kWh, maar een vast bedrag per aansluiting betalen. In het

Toepassing van finite difference- en finite element methoden voor het oplossen van een aantal stationaire grondwaterstromingsproblemen

NARCIS (Netherlands)

Wesseling, J.G.

1977-01-01

In dit verslag worden de oplossingsmethoden met de bijbehorende zelfontwikkelde FORTRAN computerprogramma's van de volgende stationaire grondwaterstromingsgevallen gegeven: - Analyse van de grondwaterstroming in een horizontaal vlak over een gedeelte van de Astense Aa, waar van plaats tot plaats

Die gebruik van tegnologie vir die ontwikkeling van professionele karaktereienskappe of sagte vaardighede van onderwysers deur afstandsonderrig

Directory of Open Access Journals (Sweden)

Johanna G. Ferreira

2016-02-01

Full Text Available Die doel van hierdie artikel was om ondersoek in te stel na die mate waartoe tegnologie suksesvol gebruik kan word om onderwysstudente deur afstandsonderrig op te lei. Omdat die sogenaamde sagte vaardighede en meegaande karatereienskappe eie is aan professies soos dié van medici of ouditeure, was dit nodig om te bepaal of onderwys wel as ’n professie beskou kan word. Die literatuur bevestig dit egter en gevolglik word aanvaar dat onderwys ’n professie is met gepaardgaande ‘sagte vaardighede’ of karaktereienskappe wat eie aan die beroep is. Vir effektiewe onderwys is die verwerwing van sodanige sagte vaardighede noodsaaklik. Die sagte vaardighede in die onderwysprofessie is derhalwe ondersoek en bespreek om ’n idee te kry van wat hierdie vaardighede behels en hoe hulle deur onderwysstudente ontwikkel en toegeëien kan word. Ten slotte is voorstelle gemaak oor hoe tegnologie ingespan kan word om sagte vaardighede by voornemende onderwysers deur afstandsonderrig te vestig.

Broeigedrag en -sukses van tuinduiwe

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Pieter le Roux

2013-02-01

Full Text Available Broei-aktiwiteite van tuinduiwe (Columba livia in die Bloemfonteinse stadsgebied vind dwarsdeur die jaar plaas met ’n afname gedurende die laat somermaande wanneer seisoenale reënval in die streek ’n hoogtepunt bereik. Nesstrukture is relatief primitief en word gekenmerk deur ’n losse samestelling van nesmateriaal op opgehoopte, droë voëlmis. Broeisels van twee eiers is die mees algemene grootte en die eiers word gewoonlik binne twee dae ná mekaar gelê. Beide ouers is by die broeiproses van meer as twee weke betrokke, waartydens die eiers ’n progressiewe afname in massa ondergaan. Pas uitgebroeide neskuikens is met geel dons bedek en is grootliks hulpeloos. Egte vere begin eers ná die eerste week te voorskyn kom, en vanaf die derde week kan individue wankelrig rondbeweeg. Afgesien van die eerste paar dae na uitbroei, handhaaf neskuikens van seldsame enkeleier-broeisels deurgaans ’n laer liggaammassa as dié van normale broeisels. Die broeisukses van 247 broeipare vir hierdie studie is 34%. Eierverlies is hoër as die mortaliteitsyfer van neskuikens, en word veral deur klimaatsfaktore soos reënval geaffekteer. Predasie blyk die belangrikste faktor te wees wat die mortaliteitsyfer van neskuikens beïnvloed. Antagonistiese interaksie tussen krans- en tuinduiwe, asook moontlike intraspesie-aggressie, speel egter ook ’n beduidende rol.

Dutch Water Mining: Potentie van een zuiverend landschap van overvloed

NARCIS (Netherlands)

Os, van E.; Kruijs, A.; Bomas, B.; Poelman, M.; Pater, de M.; Bokhoven, van D.

2012-01-01

De blauwalg in het Volkerak - Zoommeer zorgt jaarlijks voor veel overlast. In de zomerperiode zijn giftig water en stank een hinderlijk fenomeen voor iedereen. Met de techniek Dutch Water Mining verdwijnt de overlast van blauwalgen. Voor de omliggende landbouwbedrijven ontstaat de zekerheid van een

Barcode van DNA. Democratisering van de taxonomie door digitaal identificatiesysteem

NARCIS (Netherlands)

Bakker, F.T.

2011-01-01

Het herkennen van biologische soorten aan de hand van een gestandaardiseerde DNA-barcode heeft de laatste tijd een enorme vlucht genomen. Gedreven door aan de ene kant de biodiversiteitscrises en de mogelijke global change, en aan de andere kant zowel razendsnelle technologische vooruitgang als ook

Die taak van akademiese geletterdheid/hede binne die konteks van ...

African Journals Online (AJOL)

Opsomming. Die vestiging van Akademiese Geletterdheid by tersiêre instansies in Suid-Afrika het gegroei uit die besef dat 'n goedontwikkelde akademiese taalvermoë essensieel is vir akademiese prestasie. Gepubliseerde literatuur getuig van die belangrike verskuiwings wat oor die afgelope aantal dekades plaasgevind ...

Contractiemechanisme en elektrolythuishouding van het geïsoleerde, overlevende rattehart, mede in verband met de werking van insuline

NARCIS (Netherlands)

Meijler, F.L.; Offerijns, F.G.J.; Willebrands, A.F.; Groen, J.

1959-01-01

Het waarnemen van een effect van insuline op de contracties van het geïsoleerde, overlevende rattenhart was aanleiding om de fysische verrichtingen in samenhang van het gehalte aan water en elektrolyten van dit orgaan tot onderwerp van studie te maken. Daarbij werd een zo goed mogelijk aan de

Die invloed van drie kruisbestuiwers op die saadinhoud van Minneola tangelo (Citrus parodist x C reticulata

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H. J. Esterhuizen

1991-07-01

Full Text Available Die invloed van verskillende kruisbestuiwers (Clementine, Empress en Valencia op die gemiddelde saadinhoud van Minneo­la tangelo is ondersoek. Clementine en Empress as kruisbestuiwers het die grootste invloed op die gemiddelde saadinhoud van die vrugte gehad, terwyl dié van Valencia nie noemenswaardig was nie. Die gemiddelde saadinhoud van die vrugte het afgeneem met toename in afstand vanaf die kruisbestuiwer. Indien ’n beperking op die afstand tussen kultivar en kruisbestuiwer geplaas word, sal ’n groter persentasie vrugte aan uitvoerstandaarde ten opsigte van saadinhoud voldoen.

Rapport van het onderzoek naar de kosten, verbonden aan het bewaren van consumptie-aardappelen