Publications
Below you can find a list of our published research.
Below you can find a list of our published research.
39 results
Cited 13 times since 2011 (1 per year) source: EuropePMC
Clinical and translational allergy, Volume 1, Issue 1, 21 3 2011, Pages 18 Difference in symptom severity between early and late grass pollen season in patients with seasonal allergic rhinitis. de Weger LA, Beerthuizen T, Gast-Strookman JM, van der Plas DT, Terreehorst I, Hiemstra PS, Sont JK
Background: For the development of forecasts for seasonal allergic rhinitis symptoms, it is essential to understand the relationship between grass pollen concentrations and the symptoms of grass pollen allergic patients. Objective: The aim of this study was to delineate this relationship between seasonal allergic rhinitis symptoms and grass pollen concentrations in the Netherlands. Methods: Grass pollen allergic patients (n = 80 [2007] - 84 [2008]) were enrolled into the study. They were asked t... Abstract
Cited 7 times since 2009 (0.5 per year) source: EuropePMC
Microscopy research and technique, Volume 72, Issue 6, 1 1 2009, Pages 424-430 Detection of pollen grains in multifocal optical microscopy images of air samples. Landsmeer SH, Hendriks EA, de Weger LA, Reiber JH, Stoel BC
Pollen is a major cause of allergy and monitoring pollen in the air is relevant for diagnostic purposes, development of pollen forecasts, and for biomedical and biological researches. Since counting airborne pollen is a time-consuming task and requires specialized personnel, an automated pollen counting system is desirable. In this article, we present a method for detecting pollen in multifocal optical microscopy images of air samples collected by a Burkard pollen sampler, as a first step in an... Abstract
Cited 1 times since 2009 (0.1 per year) source: EuropePMC
Nederlands tijdschrift voor geneeskunde, Volume 153, Issue 17, 1 1 2009, Pages 798-803 [Ambrosia in the Netherlands. Allergic sensitisation and the distribution of plants and pollen]. de Weger LA, van der Linden AC, Terreehorst I, van der Slikke WJ, van Vliet AJ, Hiemstra PS
Cited 2 times since 2009 (0.1 per year) source: EuropePMC
Nederlands tijdschrift voor geneeskunde, Volume 153, 1 1 2009, Pages A1410 [The effect of climate change on pollen allergy in the Netherlands]. de Weger LA, Hiemstra PS
Climate change can exert a range of effects on pollen, which might have consequences for pollen-allergic patients. New allergenic pollen types might appear in the Netherlands, like common ragweed and olive, which result in allergy patients developing allergies that scarcely occur in the Netherlands at present. Trees, such as birches and planes, might produce larger quantities of pollen, which could result in more severe symptoms. The pollen season might become longer thereby extending the period... Abstract
Cited 63 times since 1998 (2.4 per year) source: EuropePMC
Molecular plant-microbe interactions : MPMI, Volume 11, Issue 1, 1 1 1998, Pages 45-56 A two-component system plays an important role in the root-colonizing ability of Pseudomonas fluorescens strain WCS365. Dekkers LC, Bloemendaal CJ, de Weger LA, Wijffelman CA, Spaink HP, Lugtenberg BJ
We describe the characterization of a novel Tn5lacZ colonization mutant of the efficiently colonizing Pseudomonas fluorescens strain WCS365, mutant strain PCL1210, which is at least 300- to 1,000-fold impaired in colonization of the potato root tip after co-inoculation of potato stem cuttings with a 1:1 mixture of mutant and parental cells. Similarly, the mutant is also impaired in colonization of tomato, wheat, and radish, indicating that the gene involved plays a role in the ability of P. fluo... Abstract
Cited 13 times since 1997 (0.5 per year) source: EuropePMC
Antonie van Leeuwenhoek, Volume 72, Issue 4, 1 1 1997, Pages 365-372 Use of a lux-based procedure to rapidly visualize root colonisation by Pseudomonas fluorescens in the wheat rhizosphere. de Weger LA, Kuiper I, van der Bij AJ, Lugtenberg BJ
The bioluminescently marked Pseudomonas fluorescens strain 5RL, has been used previously to follow colonisation of soy bean roots (De Weger et al. [1991] Appl. Environ. Microbiol. 57:36-41). In the present paper the method has been further developed and optimized for wheat roots and it is used to get a quick overview of the colonisation patterns of many different root systems at the same time. Colonisation was followed on wheat plants grown in our gnotobiotic sand system (Simons et al., 1996. Mo... Abstract
Cited 107 times since 1996 (3.9 per year) source: EuropePMC
Molecular plant-microbe interactions : MPMI, Volume 9, Issue 7, 1 1 1996, Pages 600-607 Gnotobiotic system for studying rhizosphere colonization by plant growth-promoting Pseudomonas bacteria. Simons M, van der Bij AJ, Brand I, de Weger LA, Wijffelman CA, Lugtenberg BJ
A gnotobiotic system for studying tomato rhizosphere colonization by Pseudomonas bacteria was developed. The system is based on sterile seedlings that are inoculated with one or two strains and subsequently grown in a sterile glass tube containing quartz sand. After 7 days of growth in a climate-controlled growth chamber, the number of bacteria present on the root tip was analyzed. The system was optimized with respect to root morphology, inoculation of the seedling, and isolation of root tip ba... Abstract
Cited 3 times since 1996 (0.1 per year) source: EuropePMC
Journal of bacteriology, Volume 178, Issue 7, 1 1 1996, Pages 1955-1961 A novel cell surface polysaccharide in Pseudomonas putida WCS358, which shares characteristics with Escherichia coli K antigens, is not involved in root colonization. de Weger LA, Bloemberg GV, van Wezel T, van Raamsdonk M, Glandorf DC, van Vuurde J, Jann K, Lugtenberg BJ
Previously we have shown that flagella and the O-specific polysaccharide of lipopolysaccharide play a role in colonization of the potato root by plant growth-promoting Pseudomonas strains WCS374 and WCS358. In this paper, we describe a novel cell surface-exposed structure in Pseudomonas putida WCS358 examined with a specific monoclonal antibody. This cell surface structure appeared to be a polysaccharide, which was accessible to the monoclonal antibody at the outer cell surface. Further study re... Abstract
Cited 20 times since 1996 (0.7 per year) source: EuropePMC
Applied and environmental microbiology, Volume 62, Issue 3, 1 1 1996, Pages 1076-1080 Plasmid Stability in Pseudomonas fluorescens in the Rhizosphere. van der Bij AJ, de Weger LA, Tucker WT, Lugtenberg B
Plasmids belonging to various incompatibility (Inc) groups were introduced into the efficiently root-colonizing strain Pseudomonas fluorescens WCS365, and their stabilities in complex and minimal media and in the rhizospheres of tomato, wheat, and potato plants grown under gnotobiotic conditions without selection pressure were tested. The IncP plasmid was found to be highly unstable under all conditions tested, whereas the IncQ and IncW plasmids showed intermediate stabilities and the plasmids p... Abstract
Cited 43 times since 1991 (1.3 per year) source: EuropePMC
Applied and environmental microbiology, Volume 57, Issue 12, 1 1 1991, Pages 3641-3644 Use of Bioluminescence Markers To Detect Pseudomonas spp. in the Rhizosphere. de Weger LA, Dunbar P, Mahafee WF, Lugtenberg BJ, Sayler GS
The use of bioluminescence as a sensitive marker for detection of Pseudomonas spp. in the rhizosphere was investigated. Continuous expression of the luxCDABE genes, required for bioluminescence, was not detectable in the rhizosphere. However, when either a naphthalene-inducible luxCDABE construct or a constitutive luxAB construct (coding only for the luciferase) was introduced into the Pseudomonas cells, light emission could be initiated just prior to measurement by the addition of naphthalene o... Abstract
Cited 54 times since 1991 (1.6 per year) source: EuropePMC
Molecular microbiology, Volume 5, Issue 3, 1 1 1991, Pages 647-655 The ferric-pseudobactin receptor PupA of Pseudomonas putida WCS358: homology to TonB-dependent Escherichia coli receptors and specificity of the protein. Bitter W, Marugg JD, de Weger LA, Tommassen J, Weisbeek PJ
The initial step in the uptake of iron via ferric pseudobactin by the plant-growth-promoting Pseudomonas putida strain WCS358 is binding to a specific outer-membrane protein. The nucleotide sequence of the pupA structural gene, which codes for a ferric pseudobactin receptor, was determined. It contains a single open reading frame which potentially encodes a polypeptide of 819 amino acids, including a putative N-terminal signal sequence of 47 amino acids. Significant homology, concentrated in fou... Abstract
Cited 35 times since 1990 (1 per year) source: EuropePMC
Applied and environmental microbiology, Volume 56, Issue 8, 1 1 1990, Pages 2462-2470 Characterization of Root Surface and Endorhizosphere Pseudomonads in Relation to Their Colonization of Roots. van Peer R, Punte HL, de Weger LA, Schippers B
An extensive colonization of the endorhizosphere by fluorescent pseudomonads was observed in tomato plants grown on artificial substrates. These studies reveal that a significantly higher percentage of pseudomonads obtained from the endorhizosphere (30%) reduced plant growth than those obtained from the root surface (4%). Lipopolysaccharide patterns, cell envelope protein patterns, and other biochemical characteristics indicated that Pseudomonas isolates obtained from the endorhizosphere are dis... Abstract
Cited 17 times since 1989 (0.5 per year) source: EuropePMC
Journal of bacteriology, Volume 171, Issue 5, 1 1 1989, Pages 2819-2826 Cloning and characterization of a gene encoding an outer membrane protein required for siderophore-mediated uptake of Fe3+ in Pseudomonas putida WCS358. Marugg JD, de Weger LA, Nielander HB, Oorthuizen M, Recourt K, Lugtenberg B, van der Hofstad GA, Weisbeek PJ
In iron-limited environments plant-growth-stimulating Pseudomonas putida WCS358 produces a yellow-green fluorescent siderophore called pseudobactin 358. Ferric pseudobactin 358 is efficiently taken up by cells of WCS358 but not by cells of another rhizophere-colonizing strain, Pseudomonas fluorescens WCS374. A gene bank containing partial Sau3A DNA fragments from WCS358 was constructed in a derivative of the broad-host-range cosmid pLAFR1. By mobilization of this gene bank to strain WCS374 a cos... Abstract
Cited 14 times since 1989 (0.4 per year) source: EuropePMC
Journal of bacteriology, Volume 171, Issue 5, 1 1 1989, Pages 2756-2761 Mutational changes in physiochemical cell surface properties of plant-growth-stimulating Pseudomonas spp. do not influence the attachment properties of the cells. de Weger LA, van Loosdrecht MC, Klaassen HE, Lugtenberg B
Bacteriophage-resistant mutant strains of the root-colonizing Pseudomonas strains WCS358 and WCS374 lack the O-antigenic side chain of the lipopolysaccharide, as was shown by the loss of the typical lipopolysaccharide ladder pattern after analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. These strains differed from their parent strains in cell surface hydrophobicity and in cell surface charge. The observed variation in these physicochemical characteristics could be explained... Abstract
Cited 23 times since 1988 (0.6 per year) source: EuropePMC
Journal of bacteriology, Volume 170, Issue 10, 1 1 1988, Pages 4693-4698 Siderophore-mediated uptake of Fe3+ by the plant growth-stimulating Pseudomonas putida strain WCS358 and by other rhizosphere microorganisms. de Weger LA, van Arendonk JJ, Recourt K, van der Hofstad GA, Weisbeek PJ, Lugtenberg B
Under iron-limited conditions, Pseudomonas putida WCS358 produces a siderophore, pseudobactin 358, which is essential for the plant growth-stimulating ability of this strain. Cells of strain WCS358, provided that they have been grown under Fe3+ limitation, take up 55Fe3+ from the 55Fe3+-labeled pseudobactin 358 complex with Km and Vmax values of 0.23 microM and 0.14 nmol/mg of cell dry weight per min, respectively. Uptake experiments with cells treated with various metabolic inhibitors showed th... Abstract
Cited 125 times since 1987 (3.4 per year) source: EuropePMC
Journal of bacteriology, Volume 169, Issue 6, 1 1 1987, Pages 2769-2773 Flagella of a plant-growth-stimulating Pseudomonas fluorescens strain are required for colonization of potato roots. De Weger LA, van der Vlugt CI, Wijfjes AH, Bakker PA, Schippers B, Lugtenberg B
The role of motility in the colonization of potato roots by Pseudomonas bacteria was studied. Four Tn5-induced flagella-less mutants of the plant-growth-stimulating P. fluorescens WCS374 appeared to be impaired in their ability to colonize growing potato roots. Abstract
Cited 21 times since 1987 (0.6 per year) source: EuropePMC
Journal of bacteriology, Volume 169, Issue 4, 1 1 1987, Pages 1441-1446 Lipopolysaccharides of Pseudomonas spp. that stimulate plant growth: composition and use for strain identification. de Weger LA, Jann B, Jann K, Lugtenberg B
The outer membrane proteins of a series of fluorescent, root-colonizing, plant-growth-stimulating Pseudomonas spp. having been characterized (L. A. de Weger et al., J. Bacteriol. 165:585-594, 1986), the lipopolysaccharides (LPSs) of these strains were examined. The chemical composition of the LPSs of the three best-studied plant-growth-stimulating Pseudomonas strains WCS358, WCS361, and WCS374 and of P. aeruginosa PAO1 as a reference strain was determined and appeared to differ from strain to st... Abstract
Cited 17 times since 1987 (0.5 per year) source: EuropePMC
Plant physiology, Volume 83, Issue 2, 1 1 1987, Pages 244-247 Control of the development of iron-efficiency reactions in potato as a response to iron deficiency is located in the roots. Bienfait HF, de Weger LA, Kramer D
Roots of potato plants (Solanum tuberosum cv Bintje) growing on low Fe nutrient solution developed the characteristic Fe efficiency reactions, such as high ferric reductase activity, proton extrusion and increased root hair formation. Roots from a tuber with sprout removed, when grown on Fe-free nutrient solution, also expressed these reactions; transfer to iron-containing medium resulted in their complete disappearance within 10 days. Roots growing on 2% sucrose in sterile Murashige-Skoog mediu... Abstract
Cited 52 times since 1986 (1.4 per year) source: EuropePMC
Journal of bacteriology, Volume 165, Issue 2, 1 1 1986, Pages 585-594 Siderophores and outer membrane proteins of antagonistic, plant-growth-stimulating, root-colonizing Pseudomonas spp. de Weger LA, van Boxtel R, van der Burg B, Gruters RA, Geels FP, Schippers B, Lugtenberg B
As an approach to understanding the molecular basis of the reduction in plant yield depression by root-colonizing Pseudomonas spp. and especially of the role of the bacterial cell surfaces in this process, we characterized 30 plant-root-colonizing Pseudomonas spp. with respect to siderophore production, antagonistic activity, plasmid content, and sodium dodecyl sulphate-polyacrylamide gel electrophoresis patterns of their cell envelope proteins. The results showed that all strains produce hydrox... Abstract