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PubMed2005

The evolution of self-fertilization and inbreeding depression under pollen discounting and pollen limitation.

We model the evolution of plant mating systems under the joint effects of pollen discounting and pollen limitation, using a dynamic model of inbreeding depression, allowing for partial purging of recessive lethal mutations by selfing. Stable mixed mating systems occur for a wide range of parameter values with pollen discounting alone. However, when typical levels of pollen limitation are combined with pollen discounting, stable selfing rates are always high but less than 1 (0.9<s<1 in most cases); in this situation, complete selfing does not evolve because pollen discounting becomes very large at high selfing rates, so that the automatic advantage of selfing changes to a disadvantage. These results suggest that mixed mating systems with high selfing rates can be maintained by selection, whereas mixed mating systems with low to moderate selfing rates are more likely attributable to unavoidable geitonogamous selfing.

Biological Evolution↗

PubMed2000

[Incidence of sensitization to profilin in a population allergic to pollen: responsibility of profilin in pollen polysensitizations in patients with a normal level of total IgE].

UNLABELLED: The study had the aim of establishing the incidence of sensitization to profilin (a panallergen found in pollens and foods of vegetal origin) in pollen-allergic patients. We evaluated the consequences of such sensitizations on the results of specific IgE, the positivity of skin tests and clinical signs. METHODS: 94 consenting patients, allergic to pollens (trees and/or grasses and/or weeds) replied to a questionnaire and had skin tests to purified profilin and measurement of serum anti-profilin IgE. RESULTS: Two groups were defined: one group was sensitized to profilin (GSP), with positive skin test and anti profilin IgE of 31 patients, and a group non-sensitive to profilin (GNSP) (negative skin test and anti-profilin IgE) of 41 patients. Discordant results were found in 22 patients. Taking in account the two groups, sensitization to profilin was 43%. The two groups were homogenous for age, sex, ethnics and clinical signs. Food allergy was more frequent but not statistically different (p = 0.09) in the group GSP (51.6%) than the GNSP (31.7%), in particular allergy to fruits of the Rosaceae family. Pollen polysensitization (to three species, trees, weeds and grasses) was more frequent in the GSP group (64.5%) than the GNSP (12.5). Polysensitization to pollens and foods was also more frequent in the sensitized group (65.5%) than in the non-sensitized group (12.5%). In a sub-group with normal levels of total IgE pollen polysensitization was more frequent in patients who were sensitive to profilin. On biological investigation, sensitization to profilin influenced the result of anti-latex IgE and also the IgE to many vegetal allergens. These results show the value of seeking a sensitization to profilin in patients with pollinoses.

Adult↗

PubMed2002

[Specific-pollen immunotherapy in the treatment of oral allergy syndrome in patients with tree pollen hypersensitivity].

UNLABELLED: Over the last three decades several authors have described the existence of an association between sensitivity to different pollens and sensitivity to diverse edible vegetables. Most patients with birch pollen allergy report oral allergy symptoms after eating fresh apples and other vegetable foods. Major birch pollen and apple allergens, Bet v 1 and Mal d 1, and other antigens are highly homologous; as a consequence, pollen-specific immunotherapy (SIT) might be expected to improve apple hypersensitivity. A prospective study was carried out in 27 birch pollen-sensitive patients with apple-induced OAS (oral allergy syndrome) who received injection immunotherapy for 24, or 36 months. Eight patients not submitted to SIT and followed up for 24-36 months were used as a control. Sixteen patients (59%) reported a significant reduction (37%) or a total disappearance (22%) of OAS symptoms after SIT. CONCLUSION: SIT with birch pollen extracts effectively reduces clinical apple sensitivity in some cases; these effects are not paralleled by a similar reduction of specific IgE and skin reactivity.

Adolescent↗

PubMed2004

Environmental factors affecting the start of pollen season and concentrations of airborne Alnus pollen in two localities of Galicia (NW Spain).

Alnus pollen is an early component of the annual atmospheric aerosol of the north-west regions of Spain, which causes the first occurrence of allergic symptoms. Seasonal and intra-daily variation of Alnus pollination, and the influence that main meteorological parameters exert, was studied in this paper. Monitoring was carried out from 1993-2002, by using two Lanzoni VPPS 2000 volumetric samplers. Once the atmospheric behaviour of this pollen had been identified, the final objective was to elaborate predictive models to determine the onset of the Alnus pollen season and its concentrations during the pollination period in two localities of north-west Spain (Santiago and Ourense). Winter chilling required to overcome the bud-dormancy period was similar in both cities, with around 800 Chilling Hours (C.H.) and 5.5 degrees C threshold temperature. Calculation of heat requirement for bud growth was carried out with maximum temperature, with around 50 Growth Degree Days (G.D.D. degrees C) needed, with 6 degrees C threshold temperature. Data from 2002 were used in order to determine the real validity of the models. This year was not taken into account to establish the aforementioned models. The variation between the predicted start of the pollen season and the observed season was smallest in Ourense. Verifying the proposed models for predicting daily mean concentrations of Alnus pollen during the pollen season shows that the predicted curves fits the observed variations of daily mean concentrations.

Air Pollution↗

PubMed2002

[Aberrant development of pollen in transgenic tobacco expressing bacterial iaaM gene driven by pollen- and tapetum-specific promoters].

Microsporogenesis offers an ideal model for studying gene expression, cell division and cell to cell communication during development. The role of auxin in pollen development was investigated in transgenic tobacco plants expressing the coding region of the iaaM gene from Pseudomonas syringae, under control of the promoters Lat-52 (pollen-specific) or TA-29 (tapetum-specific). IAA level in anther of transgenic plants increased significantly, and transgenic plants displayed morphological aberrations not solely attributable to pollen development(such as adventitious root formation on stems, epinastic leaf growth, delayed flowering). These results suggest that expression of Lat-52 and TA-29 are not strictly limited to anther. Anther shape was changed and the number of pollen grains per anther was reduced, but grains could be stained with aceto-carmine. Almost all flowering plants were fertile, although the number of flowers per inflorescence was reduced compared with the wild-type ones. These results suggest that auxin plays an important role in pollen development, and over-expressing auxin synthesis gene could result in aberrant development of pollen.

Bacterial Proteins↗

PubMedDate not supplied

Poplar pollen-related allergy in Ankara, Turkey: how important for patients living in a city with high pollen load?

The impact of high pollen load of particular plants on sensitized subjects is a topic of interest. We aimed to detect the clinical importance of poplar allergy in subjects with seasonal allergy living in Ankara, capital city of Turkey, having a high poplar pollen load. The subjects with seasonal allergy and demonstrating allergy to Populus alba in skin-prick tests (SPTs) (n = 20) underwent a specific nasal provocation test with P. alba allergen extract and were requested to fill in symptom-medication reports. During the same period, P. alba and Gramineae pollen counts were assessed in the city. Pollination for P. alba in Ankara for the year 2001 started in the 2nd week of March and terminated in the 1st week of May; 96.5% of subjects also had grass pollen sensitivities. By history, 85% of the subjects described mild symptoms in March and April, the expected pollinosis season for P. alba. Symptom and medication scores were higher in May and June than in March and April (p < 0.05). Allergy to P. alba pollen in patients with seasonal allergy causes mild symptoms where the dominant clinical presentation was demonstrated to be due to their additional Gramineae (grass) pollen allergy.

Adult↗

PubMedDate not supplied

Conifer pollen sensitivity in western New York: cedar pollens.

Cedar pollens might be significant allergens in areas where they have not been so considered but are prevalent. Eastern red cedar (Juniperus virginiana) and white cedar (Thuja occidentalis, American arbor vitae) are common plants in western New York. We analyzed skin test results from 158 patients with asthma, rhinitis, or both; 102 had positive skin tests to at least one pollen. Among those, 52 patients (51%) had positive skin tests to at least one of the cedar pollens. Patients sensitive on skin testing to cedar pollen were strongly likely (p < 0.0001) to be sensitive to deciduous tree, grass, or ragweed pollen. Sensitivity on skin testing to indigenous cedar pollens is common in our area of western New York and therefore could be clinically significant.

Adult↗

PubMed1985

[Pollinosis. IV. Which pollens should be tested in allergology practice? Results of determinations of allergy-causing pollens in the Zurich air 1981-1984, with reference to threshold concentrations].

The most important pollens causing pollinosis in Zurich include hazel (Corylus), alder (Alnus) and birch (Betula) in spring, grasses--including rye--in summer, and mugwort (Artemisia) in autumn. Investigations on airborne pollen of Zurich were conducted from 1981 to 1984, and assessed with special reference to threshold concentrations. The results show that sorrel (Rumex) and plantain (Plantago) also belong to the most important pollens and should therefore be included in the test spectrum for allergological examinations. The pollen of ash (Fraxinus), oak (Quercus), beech (Fagus) and plane tree (Platanus) was regularly found in high percentages during these years. Hence the clinical relevance of these tree pollens should not be underestimated, because successful diagnosis and therapy depends mainly on the use of the relevant strain of pollen.

Air Pollutants↗

PubMed1997

[Relationship between the morphological changes of Japanese cedar (Cryptomeria japonica) pollen grains and the release of major allergens from the pollen].

Release of major allergens (Cry j 1, Cry j 2) from Japanese cedar (C. japonica) pollen grains treated with high pressure was investigated. C. japonica pollen grains crushed by high pressure treatment using FRENCH Pressure Cell Press released greater amounts of major allergens, particularly Cry j 2, compared to those without crush. This suggests that the cytoplasm of C. japonica pollen grains contains more Cry j 2 than previously reported. The effect of nasal fluid on the release of major allergens from C. japonica pollen grains was analyzed in vitro. Nasal fluid from patients with nasal allergy remarkably increased the release of major allergens from pollen grains, compared to controls, and the amount of Cry j 1 was greater than Cry j 2. Further studies revealed that nasal fluid affects the outer wall of pollen grains, where Cry j 1 is located, to a greater extent than its effect on the cytoplasm, where Cry j 2 is located.

Allergens↗

PubMed1994

A Common Allergenic Epitope of Bermuda Grass Pollen Shared by Other Grass Pollens.

The present study disclosed the cross-reactivity between Bermuda grass pollen (BGP) and other grass pollens using monoclonal antibodies (MAbs) and polyclonal antiserum. MAb 9-13, directed against a group of minor allergens of BGP (Cyn d Bd68K, 48K, 38K) was found to cross-react with extracts of ten other grass pollens. Immunoblotting assays illustrated that MAb 9-13 cross-reacted with multiple components of most of these pollens, and the major cross-reactive components had molecular weights of 29-36 kD. The crossreactivity between BGP and Lol pI, the group I allergen of rye grass pollen, was further evaluated; Lol pI was recognized by MAb 9-13, but not by our MAbs/polyclonal antiserum against Cyn dI, the major allergen of BGP. These results suggest that the epitope recognized by MAb 9-13 is a common (C) epitope shared by Lol pI and Cyn d Bd68K, 48K, 38K, and Cyn dI does not share significant antigenicity with Lol pI. In a modified radio-allergosorbent test, IgE antibodies in the serum of BGP-allergic patients reacted mildly with C-epitope-bearing components of both BGP and rye grass pollens, and this binding could be blocked specifically by MAb 9-13. This suggests that in addition to an antigenic cross-reaction, the C epitope can also lead to an allergenic cross-reaction. Copyright 1994 S. Karger AG, Basel

Journal Article↗

PubMed2002

Mutants of the major ryegrass pollen allergen, Lol p 5, with reduced IgE-binding capacity: candidates for grass pollen-specific immunotherapy.

More than 400 million individuals are sensitized to grass pollen allergens. Group 5 allergens represent the most potent grass pollen allergens recognized by more than 80 % of grass pollen allergic patients. The aim of our study was to reduce the allergenic activity of group 5 allergens for specific immunotherapy of grass pollen allergy. Based on B- and T-cell epitope mapping studies and on sequence comparison of group 5 allergens from different grasses, point mutations were introduced by site-directed mutagenesis in highly conserved sequence domains of Lol p 5, the group 5 allergen from ryegrass. We obtained Lol p 5 mutants with low IgE-binding capacity and reduced allergenic activity as determined by basophil histamine release and by skin prick testing in allergic patients. Circular dichroism analysis showed that these mutants exhibited an overall structural fold similar to the recombinant Lol p 5 wild-type allergen. In addition, Lol p 5 mutants retained the ability to induce proliferation of group 5 allergen-specific T cell lines and clones. Our results demonstrate that a few point mutations in the Lol p 5 sequence yield mutants with reduced allergenic activity that represent potential vaccine candidates for immunotherapy of grass pollen allergy.

Allergens↗

PubMed1994

Characterization of a birch pollen allergen, Bet v III, representing a novel class of Ca2+ binding proteins: specific expression in mature pollen and dependence of patients' IgE binding on protein-bound Ca2+.

A cDNA coding for a birch pollen allergen, Bet v III, with significant sequence homology to Ca2+ binding proteins was isolated from an expression cDNA library using serum IgE from a patient who was allergic to pollen. The deduced amino acid sequence of the pollen allergen contained three typical Ca2+ binding sites. Peptides mimicking the Ca2+ binding sites of Bet v III were synthesized and shown to bind 45Ca in blot overlays. The binding of patients' IgE to the recombinant allergen depended on the native protein conformation and protein-bound Ca2+. Depletion of Ca2+ led to a reversible loss of the IgE binding thus representing a conformational IgE epitope adopted by a polypeptide upon Ca2+ binding. By RNA hybridization it was demonstrated that Bet v III is expressed preferentially in mature pollen. Bet v III therefore represents a pollen allergen which because of its unique structural features also belongs to a novel class of Ca2+ binding proteins.

Allergens↗

PubMed1989

Fluctuation of the number of CD-1(T6)-positive dendritic cells, presumably Langerhans cells, in the nasal mucosa of patients with an isolated grass-pollen allergy before, during, and after the grass-pollen season.

A monoclonal antibody against CD-1(T6) was used for studies in the nasal mucosa of patients with isolated grass-pollen allergy to determine whether the number of CD-1-positive cells, presumably Langerhans cells, depends on the season in which the nasal biopsy is performed. An earlier study had demonstrated that during the grass-pollen season, there are significantly more CD-1-positive cells in nasal mucosa of patients with isolated grass-pollen allergy than in nonallergic control subjects without nasal complaints. During the grass-pollen season, the nasal epithelium of patients with an isolated grass-pollen allergy demonstrated significantly more CD-1-positive cells than before and after the season. Before and after the season, the number of CD-1-positive cells in epithelium of the allergic patients was not significantly greater than the corresponding number in epithelium of nonallergic subjects without nasal complaints.

Adolescent↗

PubMed1993

Analysis of cross-reactivity between sunflower pollen and other pollens of the Compositae family.

The sera of 20 patients with Compositae pollen allergy were investigated for the presence of IgE antibodies reacting against sunflower pollen by means of RAST and immunoblotting studies. Thirteen IgE-binding bands were detected with molecular weights ranging from 14.4 to 94 kd. Two of these bands, with molecular weights of 24 and 25 kd, contained major allergens that reacted strongly with 100% (24 kd) and 95% (25 kd) of the sera, respectively. Cross-reactivity between sunflower and other Compositae pollens (mugwort, marguerite, dandelion, golden rod, and short ragweed) was revealed by RAST and immunoblotting inhibition experiments. Mugwort pollen exhibited the greatest degree of allergenic homology (cross-reactivity) with sunflower pollen, whereas at the other end of the spectrum, short ragweed showed less cross-reactive epitopes.

Allergens↗

PubMed2006

Analysis of IgE binding proteins of mesquite (Prosopis juliflora) pollen and cross-reactivity with predominant tree pollens.

Pollen from the mesquite tree, Prosopis juliflora, is an important source of respiratory allergy in tropical countries. Our aim was to partially characterize the IgE binding proteins of P. juliflora pollen extract and study cross-reactivity with prevalent tree pollen allergens. Intradermal tests with P. juliflora and five other tree pollen extracts were performed on respiratory allergy patients from Bikaner (arid) and Delhi (semi arid). Prosopis extract elicited positive skin reactions in 71/220 of the patients. Sera were collected from 38 of these 71 patients and all demonstrated elevated specific IgE to P. juliflora. Immunoblotting with pooled patients' sera demonstrated 16 IgE binding components, with components of 24, 26, 29, 31, 35, 52, 58, 66 and 95 kDa recognized by more than 80% of individual patients' sera. P. juliflora extract is allergenically potent requiring 73 ng of self-protein for 50% inhibition of IgE binding in ELISA inhibition. Cross-inhibition assays showed close relationship among P. juliflora, Ailanthus excelsa, Cassia siamea and Salvadora persica. IgE binding components of 14, 41, 52 and 66 kDa were shared allergens whereas 26 and 29 kDa were specific to P. juliflora. The findings suggest that purification of cross-reactive allergens will be helpful for diagnosis and immunotherapy of tree pollen allergic patients.

Adolescent↗

PubMed2003

A novel male-sterile mutant of Arabidopsis thaliana, faceless pollen-1, produces pollen with a smooth surface and an acetolysis-sensitive exine.

A mutant exhibiting conditional male sterility, in which fertility was restored under conditions of high humidity, was identified in T-DNA tagged lines of Arabidopsis thaliana. Scanning electron microscopy (SEM) demonstrated that the pollen surface was almost smooth and the reticulate pattern not prominent. Thus, the mutant was named faceless pollen-1 (flp1). Transmission electron microscopy (TEM) revealed that the smooth appearance was due to tryphine filling in the exine cavities and covering the pollen surface. The lipid droplets in the tryphine of mutant pollen were smaller and more numerous than those of the wild type. SEM analysis also demonstrated that pollen exine was easily damaged by acetolysis, suggesting that a component of exine, sporopollenin, was defective in the mutant. In addition, the stems and siliques had reduced amounts of wax crystals. A predicted amino acid sequence of the cDNA that corresponded to the tagged gene, fip1, showed sequence similarity to proteins involved in wax biosynthesis. The FLP1 protein is likely to play a role in the synthesis of the components of tryphine, sporopollenin of exine and the wax of stems and siliques.

Acetic Acid↗

PubMed2004

Two-generation analysis of pollen flow across a landscape V: a stepwise approach for extracting factors contributing to pollen structure.

Patterns of pollen dispersal are central to both the ecology and evolution of plant populations. However, the mechanisms controlling either the dispersal process itself or our estimation of that process may be influenced by site-specific factors such as local forest structure and nonuniform adult genetic structure. Here, we present an extension of the AMOVA model applied to the recently developed TWOGENER analysis of pollen pool structure. This model, dubbed the Stepwise AMOVA (StAMOVA), focuses on determining to what extent ecological, demographic, and/or environmental factors influence the observed genetic variation in spatially separated pollen pools. The analysis is verified for efficacy, using an extensive battery of simulations, illustrating: (1) how nonuniform adult genetic structure influences the differentiation of spatially separated pollen pools, and (2) how effectively the Stepwise analysis performs in carrying out the appropriate corrections. Finally, the model is applied to a Quercus alba data set, from which we have prior evidence that the adult genetic structure is nonuniformly distributed across the sampling landscape. From this data set, we show how the Stepwise model can be applied to remove the effects of spatial adult genetic structure on pollen pool differentiation and contrast these results with those derived from the original TWOGENER analysis.

Genetics, Population↗

PubMed2005

An olive pollen protein with allergenic activity, Ole e 10, defines a novel family of carbohydrate-binding modules and is potentially implicated in pollen germination.

CBMs (carbohydrate-binding modules) are the most common non-catalytic modules associated with enzymes active in plant cell-wall hydrolysis. They have been frequently identified by amino acid sequence alignments, but only a few have been experimentally established to have a carbohydrate-binding activity. A small olive pollen protein, Ole e 10 (10 kDa), has been described as a major inducer of type I allergy in humans. In the present study, the ability of Ole e 10 to bind several polysaccharides has been analysed by affinity gel electrophoresis, which demonstrated that the protein bound 1,3-beta-glucans preferentially. Analytical ultracentrifugation studies confirmed binding to laminarin, at a protein/ligand ratio of 1:1. The interaction of Ole e 10 with laminarin induced a conformational change in the protein, as detected by CD and fluorescence analyses, and an increase of 3.6 degrees C in the thermal denaturation temperature of Ole e 10 in the presence of the glycan. These results, and the absence of alignment of the sequence of Ole e 10 with that of any classified CBM, indicate that this pollen protein defines a novel family of CBMs, which we propose to name CBM43. Immunolocalization of Ole e 10 in mature and germinating pollen by transmission electron microscopy and confocal laser scanning microscopy demonstrated the co-localization of Ole e 10 and callose (1,3-beta-glucan) in the growing pollen tube, suggesting a role for this protein in the metabolism of carbohydrates and in pollen tube wall re-formation during germination.

Allergens↗