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PubMed2004

Fast pollen tube growth in Conospermum species.

BACKGROUND AND AIMS: An unusual form of pollen tube growth was observed for several Conospermum species (family Proteaceae). The rate of pollen tube growth, the number of tubes to emerge and the ultrastructure of these tubes are given here. METHODS: Pollen was germinated in vitro in different sucrose concentrations and in the presence of calcium channel blockers, and tube emergence and growth were recorded on a VCR. Measurements were taken of the number of tubes to emerge and rate of tube emergence. Pollen behaviour in vivo was also observed. The ultrastructure of germinated and ungerminated pollen was observed using TEM. RESULTS: After 10 s to 3 min in germination medium, up to three pollen tubes emerged and grew at rates of up to 55 micro m s(-1); the rate then slowed to around 2 micro m s(-1), 30 s after the initial growth spurt. Tubes were observed to grow in pulses, and the pulsed growth continued in the presence of calcium channel blockers. Optimal sugar concentration for pollen germination was 300 g L(-1), in which up to 81 % of pollen grains showed fast germination. Germination and emergence of multiple tubes were observed in sucrose concentrations of 100-800 g L(-1). The vegetative and generative nuclei moved into one of the tubes. Multiple tubes from a single grain were observed on the stigma. Under light microscopy, the cytoplasm in the tube showed a clear region at the tip. The ultrastructure of C. amoenum pollen showed a bilayered exine, with the intine being very thick at the pores, and elsewhere having large intrusions into the plasma membrane. The cytoplasm was dense with vesicles packed with inner tube cell wall material. Golgi apparatus producing secretory vesicles, and mitochondria were found throughout the tube. The tube wall was bilayered; both layers being fibrous and loosely packed. CONCLUSIONS: It is proposed that, for Conospermum, initial pollen tube wall constituents are manufactured and stored prior to pollen germination, and that tube extension occurs as described in the literature for other species, but at an exceptionally fast rate.

Biological Transport↗
PubMed1983

Composition and protein quality of honeybee-collected pollen of Eucalyptus marginata and Eucalyptus calophylla.

The composition and protein quality of the two most important Western Australian export-quality pollens were investigated. Crude pollen protein content was 20.6% and 27.9% for Jarrah (Eucalyptus marginata) and Marri (Eucalyptus calophylla), respectively. Lysine was the limiting amino acid relative to the FAO protein scoring pattern (Food and Agriculture Organization of the United Nations), and the amino acid scores were 0.73 and 0.66 for Jarrah and Marri pollen, respectively. Apparent biological value (BV) was 61.7 for Jarrah pollen, 66.9 for Marri pollen and 71.4 for the casein controls. Adjusted protein efficiency ratio (PER) values were 2.5, 1.2 and 1.1 for casein and Jarrah and Marri pollens, respectively. Apparent net protein utilization (NPU) was significantly reduced for both pollens (32.8 for Jarrah and 39.5 for Marri) compared to casein (63.6). The low apparent NPU values result from the relatively low digestibility of pollens. Apparent digestibility was 52 and 59% for Jarrah and Marri pollen compared to 89% for casein. Although both Jarrah and Marri pollen are relatively high in protein and have favorable amino acid patterns, their relatively low digestibility will be a limiting factor in their usefulness as a food for humans and monogastric animals. The proximate analysis and mineral content of the pollens are also presented.

Amino Acids↗
PubMed2003

Rate of dehydration of corn (Zea mays L.) pollen in the air.

The water content of corn (Zea mays L.) pollen directly affects its dispersal in the atmosphere through its effect on settling speed and viability. Therefore, the rate of water loss from pollen after being shed from the anther is an important component of a model to predict effective pollen transport distances in the atmosphere. The rate of water loss from corn pollen in air was determined using two methods: (1) by direct weighing of samples containing approximately 5 x 10(4) grains, and (2) by microscopic measurement of the change in size of individual grains. The conductance of the pollen wall to water loss was derived from the time rate of change of pollen mass or pollen grain size. The two methods gave average conductance values of 0.026 and 0.027 cm s-1, respectively. In other experiments, the water potential, psi, of corn pollen was determined at various values of relative water content (dry weight basis), either by using a thermocouple psychrometer or by allowing samples of pollen to come to vapour equilibrium with various saturated salt solutions. Non-linear regression analysis of the data yielded psi (MPa) = -3.218 theta(-1.35) (r2 = 0.94; for -298 < or = psi < or = -1 MPa). This result was incorporated into a model differential equation for the rate of water loss from pollen. The model agreed well (r2 approximately 0.98) with the observed time-course of the decrease of water content of pollen grains exposed to a range of temperature and humidity conditions.

Algorithms↗
PubMed2000

Expression of Bra r 1 gene in transgenic tobacco and Bra r 1 promoter activity in pollen of various plant species.

Bra r 1 encodes a Ca2+-binding protein specifically expressed in anthers of Brassica rapa. In this study, we isolated a genomic clone of Bra r 1 and found sequences similar to Pollen Box core motifs and LAT56/59 box, pollen-specific cis-acting element, in the 5' upstream region of Bra r 1. Reporter gene fusion revealed that the Bra r 1 promoter directs male gametophytic expression in Nicotiana tabacum, Arabidopsis thaliana and B. napus, showing strong expression in mature pollen grains similar to that of endogenous Bra r 1. Genomic DNA of Bra r 1 was introduced into tobacco plants and the highest accumulation of Bra r 1 protein was observed in mature pollen in the same manner as reporter gene expression. Using in vitro-germinated pollen tubes of transgenic tobacco, we firstly demonstrated the subcellular localization of Bra r 1 in pollen tubes. Bra r 1 protein was distributed throughout the pollen tube of transgenic tobacco and slightly intense signals of Bra r 1 were observed in the tip region. In long-germinated pollen tubes, Bra r 1 was detected only in the cytoplasmic compartments while no signals were observed in the empty part of the pollen tube, indicating that cytoplasmic movement toward the tube tip is accompanied by Bra r 1. Hence, we suggest that Bra r 1 is involved in pollen germination and pollen tube growth.

Amino Acid Sequence↗
PubMed2004

A novel endo-beta-mannanase gene in tomato LeMAN5 is associated with anther and pollen development.

Endo-beta-mannanase (EC 3.2.1.78) is involved in cell wall disassembly and the weakening of plant tissues by degrading mannan polymers in the cell walls. Endo-beta-mannanase genes are expressed in tomato (Lycopersicon esculentum) seeds (LeMAN1 and LeMAN2) and fruits (LeMAN3 and LeMAN4). A novel endo-beta-mannanase gene (termed LeMAN5) was found in the tomato genome by genome-walking PCR and bacterial artificial chromosome library screening. The 5'-upstream region of this endo-beta-mannanase gene contained four copies of the pollen-specific cis-acting elements POLLEN1LELAT52 (AGAAA). A GUS-reporter gene driven with the putative LeMAN5 promoter (-543 to +38) was activated in anthers and pollen of transgenic Arabidopsis, with the highest beta-glucuronidase activity detected in pollen. beta-Glucuronidase expression was detected in mature pollen retained in sporangia, discharged pollen, and elongating pollen tubes in transgenic Arabidopsis. Consistently, expression of LeMAN5 mRNA and endo-beta-mannnanase activity was detected in tomato anthers and pollen. In anthers, the highest mRNA expression and endo-beta-mannanase activity were detected during late stages of anther development, when pollen maturation occurred. Endo-beta-mannanase activity was present in discharged pollen, which was easily eluted in a buffer, indicating that the enzyme proteins are probably secreted from, and deposited on, the surface of pollen. These data suggest that the LeMAN5 endo-beta-mannanase is associated with anther and pollen development.

Arabidopsis↗
PubMed2006

Exogenous free ubiquitin enhances lily pollen tube adhesion to an in vitro stylar matrix and may facilitate endocytosis of SCA.

Pollen tube adhesion and guidance on extracellular matrices within the pistil are essential processes that convey the pollen tube cell and the sperm cells to the ovule. In this study, we purified an additional molecule from the pistil that enhances pollen tube adhesion when combined with the SCA (stigma/stylar cysteine-rich adhesin)/pectin matrix in our in vitro assay. The enhancer of adhesion was identified as free ubiquitin (Ub). This was confirmed by use of bovine Ub as a substitute for lily (Lilium longiflorum Thunb.) stigma Ub. To study the interaction of SCA and Ub with the lily pollen tube, we labeled both proteins with biotin. We observed uptake of biotin-labeled SCA and Ub into the pollen tube cells in vitro using confocal microscopy. For SCA, a strong signal occurred first at the tip of the pollen tube, suggestive of an endocytosis event, and then progressively throughout the tube cytoplasm. SCA was also localized inside the in vivo pollen tube using immunogold electron microscopy and found to be present in endosomes, multivesicular bodies, and vacuoles, all known to be endocytic compartments. It was also confirmed that SCA is endocytosed in the in vitro adhesion assay. Internalization of SCA was increased in pollen tubes treated with exogenous Ub compared to those without Ub, suggesting that Ub may facilitate SCA endocytosis. These results show that Ub can act as an enhancer of pollen tube adhesion in vitro and that it is taken up into the pollen tube as is SCA. The Ub machinery may play a role in pollen tube adhesion and guidance in lily.

Amino Acid Sequence↗
PubMed1995

Flavonol 3-O-glycosyltransferases associated with petunia pollen produce gametophyte-specific flavonol diglycosides.

Wild-type petunia pollen accumulates high levels of flavonol 3-O-glycosides. Pollen from conditionally male-fertile petunia has no flavonols and is unable to germinate. Pollen function is restored both in vivo and in vitro by providing flavonol aglycones, but not flavonol glycosides, to the pollen. In the present study, incubation of an in vitro suspension of conditionally male-fertile pollen with kaempferol or quercetin resulted in the accumulation of kaempferol and quercetin 3-O-glycosides in the pollen. We identified two glycosyltransferase activities associated with the intact pollen grain that catalyze the formation of a gametophyte-specific class of flavonol glycosides. Feeding studies showed that product formation was highly specific for flavonols with an unsubstituted 3-hydroxyl group and was not dependent on an external source of UDP-hexose. Ultraviolet spectral analysis, fast atom bombardment mass spectrometry, 1H-nuclear magnetic resonance, and 13C-nuclear magnetic resonance identified the products as kaempferol and quercetin 3-O-(2"- O-beta-D-glucopyranosyl)-beta-D-galactopyranoside, identical with the flavonol 3-O-glycosides present in wild-type pollen. The sugars are linked in a 1-->2 configuration that results in a pollen-specific class of compounds. To retain both glycosyltransferase activities in a cell-free extract, it was necessary to add triton X-100, suggesting that one or both of the proteins may be associated with a pollen membrane. A model for flavonol glycoside biosynthesis and uptake into the pollen is discussed in terms of the germination requirement for flavonols.

Carbohydrate Conformation↗
PubMed2002

A cysteine-rich extracellular protein, LAT52, interacts with the extracellular domain of the pollen receptor kinase LePRK2.

Pollen germination and pollen tube growth are thought to require extracellular cues, but how these cues are perceived and transduced remains largely unknown. Pollen receptor kinases are plausible candidates for this role; they might bind extracellular ligands and thereby mediate cytoplasmic events required for pollen germination and pollen tube growth. To search for pollen-expressed ligands for pollen receptor kinases, we used the extracellular domains of three pollen-specific receptor kinases of tomato (LePRK1, LePRK2, and LePRK3) as baits in a yeast two-hybrid screen. We identified numerous secreted or plasma membrane-bound candidate ligands. One of these, the Cys-rich protein LAT52, was known to be essential during pollen hydration and pollen tube growth. We used in vivo coimmunoprecipitation to demonstrate that LAT52 was capable of forming a complex with LePRK2 in pollen and to show that the extracellular domain of LePRK2 was sufficient for the interaction. Soluble LAT52 can exist in differently sized forms, but only the larger form can interact with LePRK2. We propose that LAT52 might be a ligand for LePRK2.

Binding Sites↗
PubMed1994

Cypress pollen allergy. Identification of allergens and crossreactivity between divergent species.

Studies employing sera from 34 subjects allergic to white cypress pine (Callitris glaucophylla) pollen identified 18 IgE antibody-binding components in the pollen of this species, five of which (MWs approximately 94, 68, 64, 43 and 34 kDa) were recognized by all of the sera. Protein blotting and quantitative inhibition studies revealed clear cross-reactivity between C. glaucophylla and Cupressus sempervirens pollen proteins and striking similarities in the IgE recognition band patterns of the two pollens. Inhibition experiments with other pollen extracts revealed that sera from C. glaucophylla pollen-allergic subjects can be divided into two groups--those inhibited only by extracts from the two Cupressaceae pollens and those inhibited both by these pollen proteins and by pollen extracts from other species. Most of the crossreactions in the latter group cannot be explained on the basis of taxonomic relationships or separate sensitizations. As with previous studies on birch and olive pollens, we conclude that pollen allergenic crossreactivity is much more wide-ranging than generally believed.

Allergens↗
PubMed1997

Non-specific airway hyperresponsiveness in mono-sensitive Sicilian patients with allergic rhinitis. Its relationship to total serum IgE levels and blood eosinophils during and out of the pollen season.

BACKGROUND: Initial attempts to evaluate the association between allergic rhinitis and non-specific bronchial responsiveness has produced conflicting results. In fact, some studies showed a strong correlation and other failed to find an association. However, little is known about the effect of natural specific allergen exposure on the bronchial reactivity of mono-sensitive patients with rhinitis in the southern Mediterranean area, in relation to skin reactivity to allergens, total serum IgE levels and blood eosinophils. OBJECTIVES: The significance of the association between allergic rhinitis, and abnormal airway responsiveness with regard to the pathogenesis of asthma is unclear. For this reason, we have studied non-specific bronchial hyperreactivity, in patients with seasonal allergic rhinitis, with reference to the responsible allergen. The aim of the study was to correlate the responsiveness to bronchoprovocation with methacholine in subjects a with allergic rhinitis during and out of the pollen season with total serum IgE and blood eosinophils. METHODS: Fourty-nine non-smoking patients with clinical diagnosis of allergic rhinitis and mono-sensitive skin-prick tests to pollen allergens were enrolled in the study. Twenty patients suffered from seasonal rhinitis to Parietaria pollen, 15 patients to Gramineae pollen and 14 patients to Olea pollen. In all patients lung function measurements (assessed as response to methacholine), total serum IgE and blood eosinophil counts were measured during and out of the pollen season. RESULTS: During pollen season, 16 out of 49 rhinitis patients demonstrated values of bronchial responsiveness measured as response to inhaled methacholine in the asthmatic range whereas out of the pollen season only eight patients were in the asthmatic range. By analysing the results with reference to the responsible allergen, during the pollen season 15 out of 16 patients were Parietaria-sensitive and out of the pollen season seven out of eight patients. Finally, in Parietaria-sensitive rhinitis bronchial responsiveness significantly correlated, during and out of the pollen season, with total serum IgE and with blood eosinophil counts. CONCLUSIONS: Our results are consistent with the hypothesis that Parietaria is more important than Olea and Gramineae as a risk for developing non-specific bronchial hyperresponsiveness. On the whole, present observations provide further evidence that there is an interrelationship of allergen kind, total serum IgE, eosinophil and bronchial hyperresponsiveness suggesting that they may play a role in the development of bronchial asthma in rhinitis patients.

Adult↗
PubMed2003

Pollen counts in relation to the prevalence of allergic rhinoconjunctivitis, asthma and atopic eczema in the International Study of Asthma and Allergies in Childhood (ISAAC).

BACKGROUND: Although pollens are major allergens associated with allergic rhinoconjunctivitis and asthma, there is little information about the relative prevalence of these conditions in populations with different pollen exposures. OBJECTIVE: The purpose of this study was to investigate the relationship between pollen exposure and allergic symptoms among children in different countries. METHODS: An ecological analysis was conducted to see whether pollen exposure (pollen counts, and duration and severity of pollen seasons) is associated with symptoms of allergic rhinoconjunctivitis, asthma and atopic eczema in 28 centres within 11 countries (nine being in Europe). Data on the prevalence of symptoms in 13-14-year olds were based on the responses to the written questionnaires from the International Study of Asthma and Allergies in Childhood (ISAAC). The analysis was adjusted for gross national product and mean annual relative humidity. RESULTS: There was little relationship between pollen exposure and symptom prevalence, except for a significant inverse association between grass pollen counts and lifetime prevalence of the symptoms of allergic rhinitis (P=0.03). Almost all the regression coefficients were negative. The associations were even weaker and all non-significant when the analyses were conducted within countries, using a random intercept fixed slope model, but there was still no evidence of a positive association between pollen exposure and symptoms. CONCLUSION: There is a weak but consistent tendency for the prevalence of allergic symptoms to be inversely associated with pollen exposure. This finding accords with evidence from several countries, suggesting that the prevalence of hayfever and asthma tends to be lower in rural than in urban areas, and lowest among people living on farms. Exposure to allergenic pollen in early life does not appear to increase the risk of acquiring symptoms of respiratory allergy, and may even give some protection against them.

Adolescent↗
PubMed2005

Interannual genetic heterogeneity of pollen pools accepted by Quercus salicina individuals.

Since flowering often varies among years in wind-pollinated woody species, the genetic composition of pollen pools accepted by seed parents can differ between years. The interannual heterogeneity of pollen flow may be important for maintaining genetic diversity within populations because it can increase genetic variation within populations and the effective sizes of the populations. In this study we examined heterogeneity, using paternity analysis and analysis of molecular variance, in the genetic composition of pollen pools among different reproductive years for six Quercus salicina seed parents in an 11.56-ha plot in a temperate old-growth evergreen broadleaved forest. The genotypes at seven microsatellite loci were determined for 111 adult trees and 777 offspring of the six seed parents in 2-5 reproductive years. Genetic differentiation of pollen pools among different reproductive years for each seed parent was significant over all seed parents and for each of four seed parents that were analysed for more than 2 years, but not for either of the other two seed parents (analysed for 2 years). For both the pollen pools originating from inside the plot and those originating from outside it, genetic differentiation among different reproductive years for each seed parent was significant over all seed parents. However, among-year genetic differentiation in the pollen pools originating from within the plot was detected for all four of the seed parents that were analysed for more than 2 years, but for only one of the four in the pools originating from outside the plot. Genetic diversity (estimated as allelic richness and gene diversity) was higher for pollen pools over all reproductive years than for pollen pools in single years. These results indicate that the year-to-year genetic variation of pollen pools increases genetic diversity in offspring and is strongly affected by the variation in pollen parents within the plot because of their high pollination contributions. The high year-to-year variation in pollen parents within the plot and overall supports the hypothesis that the offspring produced across years represent a larger genetic neighbourhood.

Analysis of Variance↗
PubMed2006

Pollen-mediated gene dispersal within continuous and fragmented populations of a forest understorey species, Trillium cuneatum.

Pollen movement plays a critical role in the distribution of genetic variation within and among plant populations. Direct measures of pollen movement in the large, continuous populations that characterize many herbaceous plant species are often technically difficult and biologically unreliable. Here, we studied contemporary pollen movement in four large populations of Trillium cuneatum. Three populations, located in the Georgia Piedmont, are exposed to strong anthropogenic disturbances, while the fourth population, located in the Southern Appalachian Mountains, is relatively undisturbed. Using the recently developed TwoGener analysis, we extracted estimates of the effective number of pollen donors (N(ep)), effective mating neighbourhood size (A(ep)) and the average distance of pollen movement (delta) for each population. We extended the TwoGener method by developing inference on the paternal gametic contribution to the embryo in situations where offspring genotypes are inferred from seeds and elaiosomes of species with bisporic megagametogenesis. Our estimates indicate that maternal plants do not sample pollen randomly from a global pool; rather, pollen movement in all four populations is highly restricted. Although the effective number of pollen donors per maternal plant is low (1.22-1.66) and pollen movement is highly localized in all populations, N(ep) in the disturbed Piedmont populations is higher and there is more pollen movement than in the mountains. The distance pollen moves is greater in disturbed sites and fragmented populations, possibly due to edge effects in Trillium habitats.

Gene Flow↗
PubMed1986

Pollen seasons: forecasts of the most important allergenic plants in Finland.

Occurrence of airborne pollen in Finland has been studied for 10 years in Turku (southern Finland), 8 years in Oulu, 4 years in Kuopio (central Finland) and 7 years at Kevo (northern Lapland). Observations on the pollen seasons of alder, birch, grasses and mugwort are presented. All these pollens occur in south and mid- Finland in quantities capable of causing allergy symptoms. Except for birch pollen, allergenic pollens occur in far lower concentrations than in central Europe. In northern Lapland only birch and pine pollen concentrations are high. Pollens may occur without signs of local flowering when there are southerly winds. This finding suggests that long-distance transport is an essential contributing factor to the occurrence of pollens. There are wide year-to-year variations in the start of pollen seasons and the quantities of pollens. The variations in the start of birch and grass pollen seasons could very much depend on the mean temperature in April. However, a forecasting model based on this and other spring-time temperature parameters often fails to give sufficiently accurate forecasts.

Finland↗
PubMed1995

Comparison of IgE and IgG antibody responses of atopic individuals with sensitization to tree and grass pollens.

Sera of atopic individuals with predominant sensitization to either tree pollen (TAs) or tree and grass pollens (TGAs) as well as of nonatopic subjects (NAs) were analyzed for IgE, IgG, and IgG4 antibodies specific for grass pollens allergens. Of 600 atopic individuals with serum IgE antibodies specific for birch pollen allergens, 54% also had serum IgE antibodies specific for grass pollen. The mean titers of IgG antibodies specific for grass pollen proteins were about 10 times higher in the sera of TGAs than those in the TAs and NAs. SDS-PAGE immunoblotting analysis of grass pollen proteins using sera of TGAs, TAs, and NAs with respect to the binding of these proteins with IgE and IgG antibodies in these sera exhibited a similar pattern of variation. Quantitation by enzyme immunoassay of the antibody binding to a recombination grass pollen allergen, rKBG8.3, further demonstrated the elevated IgG antibody levels in TGAs are mainly due to a broader range of specificities, and not to high specific binding to the individual protein. Statistically significant correlation was found between IgE and IgG4 antibodies specific for the Kentucky bluegrass (KBG) extract, but not for the isolated recombinant allergen. These results indicate that the grass pollens elicit a complex array of antibody specificities in both atopics and nonatopics, and that the profile of antibodies specific to the pollen extract and pure allergens differs, suggesting that single grass allergens may be inadequate for replacing grass pollen extracts for immunotherapy.

Allergens↗
PubMed1997

Comparison of direct immunostaining and electroimmunoassay for analysis of airborne grass-pollen antigens.

Sensitive pollen-allergic patients have been reported to show allergic symptoms not only during the pollen release of allergenic plants but also both before and after the pollen season. Symptoms before the season are evidently provoked by small-sized particles originating partly from developing pollen grains, partly from other plant parts. After the pollen season, antigenic material settles on various surfaces, which thus form a new source of allergenic material. Measuring the allergen concentrations in indoor and outdoor environments demands an effective sampling method and a rapid and sensitive immunochemical analysis, especially for particles of small-sized fractions which are not detected in microscopic analyses. The efficiency of an ELISA and an immunochemical staining method was tested with monoclonal IgG against Phl p 5, the main grass allergen. The Burkard trap and MPC impactor (Marple personal cascade impactor with six-stage particle size fractionation) were compared. The sampling was carried out in southwestern Finland in the summer of 1994. The number of grass-pollen antigen spots greatly exceeded the simultaneous pollen count, indicating considerable antigen activity outside the pollen grains. The counts were especially high in small-sized fractions after the pollen season, when hardly any airborne pollen was found. Spots and pollen divided according to size were highly intercorrelated, indicating that the threshold values used were appropriate.

Air Pollution↗
PubMed2006

Brassica oleracea pollen, a new source of occupational allergens.

BACKGROUND: Vegetable pollen is a rare source of occupational allergens. Occupational allergy has only been described in the case of paprika pollen and tomato pollen. We describe a new source of occupational pollen allergy. AIM: To study the incidence and the impact of broccoli and cauliflower pollen allergy in employees involved in classical plant breeding. METHODS: Fifty-four employees of five companies working with cauliflower (Brassica oleracea botrytis) and broccoli (B. oleracea italica/cymosa) pollen were eligible for complete evaluation. Allergy to cauliflower and broccoli pollen was evaluated by questionnaire and determination of sensitization by radioallergosorbent test (RAST) and skin-prick tests (SPT). SPT and RAST were performed with a panel of commercial and homemade extracts from cauliflower and broccoli pollen. RESULTS: Work-related symptoms such as rhinitis, conjunctivitis, asthma and urticaria caused by B. oleracea pollen were reported by 44% of the participants (24/54), of whom all but one had positive SPT for cauliflower- and/or broccoli-pollen/flower extracts and 58% (14/24) had positive RAST results. Symptoms had developed within the first 2 years in 33% of the patients. Six patients had to stop or change work. CONCLUSIONS: Brassica oleracea pollen is a new source of occupational allergen with strong allergenic potential leading to symptoms in almost half of the exposed employees.

Adult↗
PubMed2002

Current understanding of cross-reactivity of food allergens and pollen.

Pollen-allergic patients frequently present allergic symptoms after ingestion of several kinds of plant-derived foods. The majority of these reactions is caused by four distinct cross-reactive structures that are present in birch pollen. Proteins that share common epitopes with Bet v 1, the major birch pollen allergen, occur in pollens of several tree species: apples, stone fruits, celery, carrot, nuts, and soybeans. Approximately 70% of our patients who are allergic to birch pollen may experience symptoms after consumption of foods from these groups. In contrast, two minor allergenic structures-profilins and cross-reactive carbohydrate determinants (CCD)-that sensitize approximately 10-20% of all pollen-allergic patients are also present in grass pollen and weed pollen. Moreover, IgE-binding proteins related to the birch pollen minor allergen Bet v 6 have been found in many vegetable foods such as apple, peach, orange, lychee fruit, strawberry, persimmon, zucchini, and carrot. Frequently, the occurrence of cross-reactive IgE antibodies is not correlated with the development of clinical food allergy. In particular, the clinical relevance of sensitization to CCD is doubtful. Generally, pollen-related allergens tend to be more labile during heating procedures and in the digestive tract compared to allergens from classical allergenic foods such as peanut. However, recent DBPCFC studies have shown that both cooked celery and roasted hazelnuts still pose an allergenic risk for pollen-sensitized subjects. Since pathogenesis-related proteins share several common features with allergens and both the Bet v 1 and the Bet v 6-related food allergens are defense-related proteins, approaches to introduce such proteins as a measure to protect plants against diseases should be performed with caution as they may increase the allergenicity of these crops.

Allergens↗