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Pollen flow in the distylous Palicourea fendleri (Rubiaceae): an experimental test of the Disassortative Pollen Flow Hypothesis.

The Disassortative Pollen Flow Hypothesis proposed by Darwin postulates that the relative position of anthers and stigmas in distylous flowers enhances pollen flow between flowers of different morphs (legitimate pollination), in comparison to flow between flowers of the same morph (illegitimate pollination). In order to test this hypothesis, we measured pollen transport, mediated by a trained Copper-rumped Hummingbird (Amazilia tobaci), between flowers of the distylous Palicourea fendleri under laboratory conditions. In individual tests, we offered to the hummingbird a pollen donor flower and two emasculated recipient flowers in a controlled sequence. After each foraging bout, we counted the number of pollen grains transported from the donor flower to the stigmas of both recipient flowers. In agreement with Darwin's hypothesis, we found that hummingbirds transport pollen of "pin" flowers in significantly higher numbers to legitimate "thrum" stigmas, even if previously visiting a "pin" flower. However, "thrum" pollen was deposited in greater numbers on illegitimate "thrum" stigmas. We interpret this asymmetry largely as the consequence of floral morphology; pollen flow was greater between anthers and stigmas that exhibit greater spatial matching. In P. fendleri, the position of floral organs along the corolla tube does not always precisely correspond. In our experimental system, the probability that the pollinator extracts a pollen grain from the anther and the probability of self-pollination were both dependent on the type of floral morph. We discuss the relevance of the latter findings in relation to other studies of pollen flow in heterostylous species.

Animals↗

Aerobiology of Artemisia airborne pollen in Murcia (SE Spain) and its relationship with weather variables: annual and intradiurnal variations for three different species. Wind vectors as a tool in determining pollen origin.

Detailed results from a 2-year survey of airborne pollen concentrations of Artemisia in Murcia are presented. Three consecutive pollen seasons of Artemisia occurring each year, related to three different species (A. campestris, A. herba-alba and A. barrelieri), were observed. A winter blooming of Artemisia could explain the incidence of subsequent pollinosis in the Murcia area. With regard to meteorological parameters, mathematical analyses showed relationships between daily pollen concentrations of Artemisia in summer-autumn and precipitations that occurred 6-8 weeks before. The cumulative percentage of insolation from 1 March seemed to be related to blooming onsets. Once pollination has begun, meteorological factors do not seem to influence pollen concentrations significantly. Intradiurnal patterns of pollen concentrations were similar for late summer and winter species (A. campestris and A. barrelieri). During autumn blooming (A. herba-alba), the intradiurnal pattern was particularly erratic. Theoretical values of wind run were obtained for each pollen season by the graphical sum of hourly wind vectors. When theoretical wind run was mapped onto the vegetation pattern, supposed pollen source locations were obtained for each hour. By comparing supposed hourly pollen origins with the intradiurnal patterns of pollen concentrations, it can be seen that this simple model explains variations in mean pollen concentrations throughout the day.

Allergens↗

Functional architecture of a late pollen promoter: pollen-specific transcription is developmentally regulated by multiple stage-specific and co-dependent activator elements.

The tomato lat52 gene encodes an essential cysteine-rich protein preferentially transcribed in the vegetative cell during pollen maturation. Detailed analyses of the identity, organization and role of cis-regulatory elements in controlling the precise developmental and tissue-specific expression of lat52 during pollen development were performed. Analysis of a series of 5' promoter deletion mutants stably introduced into tobacco demonstrated differential developmental activation of deletion mutants during pollen development. All major cis-regulatory elements required for pollen-specific transcription were located within the upstream region -492 to -52. This region was shown to comprise three independent activator domains A, B and C, each sufficient to activate the minimal CaMV 35S promoter in a pollen-specific manner. 5' deletion and gain of function approaches were used to show that domain A and the previously defined motif PBII (sub-domain B1) were largely redundant in the presence of downstream sequences in mature pollen. Within domain B two novel pollen-specific sub-domains B2 and B3 were identified. Within domain C, the activity of the PBI motif (sub-domain C1) was shown to be strictly dependent upon a downstream 20 bp pollen-specific activator unit -72 to -52 (sub-domain C2), containing two novel co-dependent regulatory elements AGAAA and TCCACCATA. These results demonstrate that transcriptional activation of lat52 is controlled by a complex of pollen-specific cis-regulatory elements which cooperate to achieve maximum levels of gene expression throughout pollen maturation. Alternative models of the interaction of identified cis-regulatory elements with putative trans-acting factors within the lat52 promoter and their developmental utilization are presented.

Enhancer Elements, Genetic↗

Fagales pollen sensitization in a birch-free area: a respiratory cohort survey using Fagales pollen extracts and birch recombinant allergens (rBet v 1, rBet v 2, rBet v 4).

BACKGROUND: Birch allergy is one of the most common pollinosis in areas where exposure to high levels of birch pollen is common. Little is known about birch sensitivity in areas without birch pollen exposure and reactivity to birch-related species within the Fagales order. OBJECTIVE: the aim was to evaluate Fagales reactivity within a population not exposed to birch pollen using epidemiological, diagnostic, and laboratory approaches by means of extracts and allergenic molecules. METHODS: A cohort of 5335 respiratory allergic patients was screened by means of skin testing birch, hazel, and oak pollen extracts. Patients were from a birch-free area, but exposed to other Fagales pollen species. A subset of patients was from an intensively cultivated hazel area. A sample of the Fagales allergic population was tested with other Fagales pollen extract (alder, hornbeam, beech, chestnut) and with apple and hazelnut. IgE detection was performed with birch, hazel, oak, apple, and hazelnut extracts, and with Bet v 1, Bet v 2, Bet v 4, and bromelain. IgE immunoblots were performed using birch and hazel extracts. Epidemiological, clinical, and laboratory data were analysed by stratifying the allergic population. RESULTS: Twenty-five percent of the pollen allergic cohort was skin test positive to at least one of the three Fagales species. Combined reactivity to the three species was recorded in 80% of this cohort. Isolated hazel pollen reactivity was recorded in 13.5% of the Fagales allergic patients. Sixty-six percent of these subjects were from the intensively cultivated hazel area. Reactivity to apple and hazelnut was detected by skin test (40%) and IgE reactivity (60%), but only 19% of the positive patients reported symptoms related to at least one of the two foods. Reactivity to Bet v 1 was recorded in 84% of the birch/hazel/oak co-reactivity group, and in 28% of the subjects with the same co-reactivity, but associating a multiple pollen sensitization. IgE to Bet v 2 (50%) and Bet v 4 (23%) panallergens were recorded positive in the latter subset. Bet v 1 prevalence ranged between 48% and 21% among subgroups of patients coming from different areas. Furthermore, an IgE reactivity to hazel-restricted allergenic components was detected among subjects coming from the same area and having a hazel isolated reactivity. CONCLUSION: Fagales allergy can be found in birch-free areas caused by the exposure to other Fagales species. Birch allergens can be useful for mimicking the allergenic extract, but are also the exclusive tools for a fine diagnostic and epidemiological approach to Fagales pollen allergy. Allergenic molecules from the hazel family will increase the panel of available reagents for the molecule-based approach to allergy diagnosis and therapy.

Adult↗

Rice Immature Pollen 1 (RIP1) is a regulator of late pollen development.

We isolated a pollen-preferential gene, RICE IMMATURE POLLEN 1 (RIP1), from a T-DNA insertional population of japonica rice that was trapped by a promoterless beta-glucuronidase (GUS) gene. Semi-quantitative reverse transcription-PCR (RT-PCR) analyses confirmed that the RIP1 transcript was abundant at the late stages of pollen development. Transgenic plants carrying a T-DNA insertion in the RIP1 gene displayed the phenotype of segregation distortion of the mutated rip1 gene. Moreover, rip1/rip1 homozygous progeny were not present. Reciprocal crosses between Rip1/rip1 heterozygous plants and the wild type showed that the rip1 allele could not be transmitted through the male. Microscopic analysis demonstrated that development in the rip1 pollen was delayed, starting at the early vacuolated stage. Close examination of that pollen by transmission electron microscopy also showed delayed formation of starch granules and the intine layer. In addition, development of the mitochondria, Golgi apparatus, lipid bodies, plastids and endoplasmic reticulum was deferred in the mutant pollen. Under in vitro conditions, germination of this mutant pollen did not occur, whereas the rate for wild-type pollen was >90%. These results indicate that RIP1 is necessary for pollen maturation and germination. This gene encodes a protein that shares significant homology with a group of proteins containing five WD40 repeat sequences. The green fluorescent protein (GFP)-RIP1 fusion protein is localized to the nucleus. Therefore, RIP1 is probably a nuclear protein that may form a functional complex with other proteins and carry out essential cellular and developmental roles during the late stage of pollen formation.

Amino Acid Motifs↗

Pollen performance before and during the autotrophic-heterotrophic transition of pollen tube growth.

For species with bicellular pollen, the attrition of pollen tubes is often greatest where the style narrows at the transition between stigmatic tissue and the transmitting tissue of the style. In this region, the tubes switch from predominantly autotrophic to predominantly heterotrophic growth, the generative cell divides, the first callose plugs are produced, and, in species with RNase-type self-incompatibility (SI), incompatible tubes are arrested. We review the literature and present new findings concerning the genetic, environmental and stylar influences on the performance of pollen before and during the autotrophic-heterotrophic transition of pollen tube growth. We found that the ability of the paternal sporophyte to provision its pollen during development significantly influences pollen performance during the autotrophic growth phase. Consequently, under conditions of pollen competition, pollen selection during the autotrophic phase is acting on the phenotype of the paternal sporophyte. In a field experiment, using Cucurbita pepo, we found broad-sense heritable variation for herbivore-pathogen resistance, and that the most resistant families produced larger and better performing pollen when the paternal sporophytes were not protected by insecticides, indicating that selection during the autotrophic phase can act on traits that are not expressed by the microgametophyte. In a study of a weedy SI species, Solanum carolinense, we found that the ability of the styles to arrest self-pollen tubes at the autotrophic-heterotrophic transition changes with floral age and the presence of developing fruits. These findings have important implications for selection at the level of the microgametophyte and the evolution of mating systems of plants.

Cucurbita↗

Diagnosis of grass pollen allergy with recombinant timothy grass (Phleum pratense) pollen allergens.

In order to establish a test system for grass pollen allergy based on the use of recombinant allergens we chose timothy grass (Phleum pratense), a widely spread grass, as a model. From a lambda gt11 cDNA expression library that we had constructed from pollen RNA of timothy grass (P. pratense), we had obtained with serum IgE from a grass pollen-allergic individual 60 IgE-binding clones. By differential testing with sera from different grass pollen-allergic patients, we selected three distinct clones encoding Phl p I (group I), Phl p V (group V) and profilin from timothy grass, which when used together allowed the diagnosis of grass pollen allergy in 97 out of 98 tested grass pollen-allergic patients employing a simple plaque lift technique. This recombinant test based on plaque lifts containing allergen-beta-galactosidase fusion proteins was compared with IgE immunoblots using crude pollen protein extracts from timothy grass. Both methods were in good agreement with RAST scores and clinical data, and proofed to be useful for the diagnosis of grass pollen allergy. Our results further indicate that a limited panel of only two recombinant grass pollen allergens, Phl p I and Phl p V, together with the plant panallergen profilin could be sufficient for the diagnosis and possibly immunotherapy of grass pollen allergy.

Adolescent↗

[The increase and decrease of the total pollen counts of Sugi (Cryptomeria japonica) due to abnormal weather during pollen scattering season].

We investigated the changing total number of airborne pollen grains of Sugi (Cryptomeria japonica) due to abnormal weather during pollen scattering season. The pollen season was divided into 7 periods by the discrepancies in forest flowering time for observations. The observation forests were located at an altitude of 150 m, 220 m, 350 m, and 500 m, and 800 m in the Rokko mountains. These were located at equal spaces, when altitude was taken in the logarithm. The distribution percentage of pollen counts from 1993 to 1998 showed an almost normal distribution level. This was demonstrated by the Log-Normal Probability paper, with a middle level altitude of a 350 m forest. We could estimate the relative rate of 5 different altitude forests against the corresponding amount of pollen as shown under, 0.09 at 150 m forest, 0.34 at 220 m forest, 0.31 at 350 m forest, 0.16 at 500 m forest, 0.10 at 800 m forest. The percentage of pollen counts at the 500 m forest in 1994 and at the 350 m forest in 1995 were decreased from 95% confidence interval. We regarded the decrease in the percentage of pollen counts during these two time, as a cause weak wind velocity and wrong wind direction in Tanba mountains. It was shown that the method for dividing pollen season in different observation forests in which altitude differs, will be useful for pollen forecasts and the pollen source countermeasure.

Air Pollution↗

Modern pollen studies in the territory of Sagalassos (Southwest Turkey) and their use in the interpretation of a Late Holocene pollen diagram.

Modern pollen precipitation studies were carried out on a regional scale in the territory of the classical city of Sagalassos (Southwest Turkey). 57 moss cushions and 7 soil samples from different vegetation types were analysed palynologically. The resulting pollen spectra were grouped into 14 vegetation groups, which were examined using discriminant analysis and principal components analysis. These numerical procedures are applied to display the structure in the data set in a comprehensive way. Some of the modern spectra groups seem to be well-defined, whereas others are difficult to distinguish from each other. After the relationships between the modern pollen spectra had been analysed, the fossil data from a core from the marsh of Gravgaz were added to the data set so that any similarities between fossil and modern spectra could be seen. A joint principal components analysis of the modern and fossil pollen spectra revealed that the pollen spectra from the earliest (ca. 2600-2500 BP; Cal. 830-590 BC till 790-520 BC) and the latest (starting at ca. 1300 BP; Cal. 660-780 AD) pollen assemblage zones have modern counterparts. On the other hand, the pollen spectra from the pollen assemblage zone dominated by Artemisia (ca. 2500-2300 BP; Cal. 790-520 BC till 410-210 BC) and from the pollen assemblage zone that indicated the practice of arboriculture (ca. 2300-1300 BP; Cal. 410-210 BC till 660-780 AD) have no close modern analogues, although individual tabulated pollen percentages revealed some similarities with some modern spectra groups.

Journal Article↗

The maize aberrant pollen transmission 1 gene is a SABRE/KIP homolog required for pollen tube growth.

Maize (Zea mays) pollen tubes grow in the styles at a rate of >1 microm/sec. We describe here a gene required to attain that striking rate. The aberrant pollen transmission 1 (apt1) gene of maize was identified by an Ac-tagged mutation that displayed a severe pollen transmission deficit in heterozygotes. Rare apt1 homozygotes can be recovered, aided by phenotypic selection for Ac homozygotes. Half of the pollen in heterozygotes and most of the pollen in homozygotes germinate short and twisted pollen tubes. The apt1 gene is 26 kb long, makes an 8.6-kb pollen-specific transcript spliced from 22 exons, and encodes a protein of 2607 amino acids. The APT1 protein is homologous to SABRE and KIP, Arabidopsis proteins of unknown function involved in the elongation of root cortex cells and pollen tubes, respectively. Subcellular localization analysis demonstrates that APT1 colocalizes with a Golgi protein marker in growing tobacco pollen tubes. We hypothesize that the APT1 protein is involved in membrane trafficking and is required for the high secretory demands of tip growth in pollen tubes. The apt1-m1(Ac) mutable allele is an excellent tool for selecting Ac transpositions because of the strong negative selection pressure operating against the parental Ac site.

Arabidopsis Proteins↗

Effects of pollen load size and composition on pollen donor performance in wild radish, Raphanus sativus (Brassicaceae).

A critical concern in the debate over the importance of sexual selection in plants is whether the nonrandom mating demonstrable in greenhouse crosses can occur in the field. Field populations likely experience smaller and more variable pollen load sizes than those that have been used in many greenhouse experiments. Therefore, we performed a greenhouse experiment in which we varied both pollen load size and composition in wild radish, Raphanus sativus, and examined the paternity of seeds. We used five maternal plants and four pairs of pollen donors. We were able to produce pollen loads of 40, 118, and 258 grains per stigma. The smallest of the pollen loads was scant enough to result in a slight, but significant reduction in seed number per fruit. While variation in pollen load composition significantly affected the proportions of seeds fathered by different donors, variation in pollen load size did not. The relative performance of different donors was constant across pollen load sizes, suggesting that, for this species, differential performance of pollen donors can occur at pollen load sizes that are likely to occur in field populations.

Journal Article↗

Pollen grain column chromatography: quantitation and biochemical analysis of ragweed-pollen solutes.

The kinetics, quantitative yield, and sequence of solute release during the extraction of allergenic substances from short ragweed (Ambrosia artemisiifolia) pollen were compared with a conventional batch-type method and the novel technique of pollen grain column chromatography. With the batch method, 14.6 +/- 1.7 mg of pollen solutes were eluted per 100 mg of dried defatted pollen in 1 minute; the 24-hour solute yield was 27.4 +/- 2.7 mg. With the column method, 3.7 +/- 1.3 mg of pollen solutes were eluted in 1 minute; the 24-hour solute yield was 29.3 +/- 2.1 mg. The kinetics of solute release with the column method were modeled as the simultaneous first-order elution of ragweed-pollen solutes into three hypothetical compartments. The theoretical initial solute concentration was 50 gm/L. The isoelectric focusing patterns, optical properties, distributions of enzymes, Ra5, and antigen E activities were consistent with the sequential separation of ragweed-pollen solutes and the three compartment model. Enzyme activities were eluted either maximally in the first minute (phosphatases and N-acetyl-beta-glucaminidase) or delayed until 10 minutes (leucine aminopeptidase). Ra5 was eluted rapidly, whereas antigen E was eluted during a more prolonged period. Pollen grain chromatography provides a simple, reproducible method for studying pollen solute release.

Acid Phosphatase↗

Olive (Olea europea) and privet (Ligustrum vulgare) pollen allergens. Identification and cross-reactivity with grass pollen proteins.

Protein blotting studies showed that three olive pollen components with mol. wts approximately 18-19, 20 and 40 kD can be considered to be major allergens. For privet pollen, the highest recognition frequencies were for allergens of mol. wts approximately 20, approximately 19, approximately 40 and approximately 70 kD. When results with the 62 subjects examined were separated into groups corresponding to their geographical locations, viz. Italy, France and Australia, subjects sensitized to olive, but not other pollens (some Italian subjects), were found to show higher frequencies of recognition of major olive allergens than subjects sensitized to olive pollen via cross-reacting allergens from unrelated pollen sources (the Australian and French subjects). Blotting, adsorption and elution and inhibition studies clearly demonstrated allergenic cross-reactivity (that is, antigenic cross-reactivity detected by IgE antibodies) between olive, privet, ryegrass (Lolium perenne) and couch grass (Bermuda grass: Cynodon dactylon) pollen components. As with our previous findings with birch pollen, we conclude that the presence of pollen-reactive IgE antibodies may not necessarily be a true reflection of the sensitizing pollen species.

Allergens↗

Skin test evaluation of genetically engineered hypoallergenic derivatives of the major birch pollen allergen, Bet v 1: results obtained with a mix of two recombinant Bet v 1 fragments and recombinant Bet v 1 trimer in a Swedish population before the birch pollen season.

BACKGROUND: More than 95% of birch pollen-allergic subjects react with the major birch pollen allergen, Bet v 1, and almost 60% of them are sensitized exclusively to this allergen. OBJECTIVE: The aim of this study was to compare the in vivo biologic activity of genetically engineered hypoallergenic derivatives of Bet v 1 (an equimolar mixture of 2 recombinant [r] Bet v 1 fragments and of rBet v 1 trimer) with that of rBet v 1 wild-type by skin prick and intradermal testing. METHODS: Birch pollen-allergic patients who had not received immunotherapy (n = 23), a group of allergic patients without birch pollen allergy (n = 12), and nonatopic persons (n = 8) from northern Europe (Sweden) underwent skin prick and intradermal testing with different concentrations of the recombinant allergens and commercial birch pollen extract before the birch pollen season. Immediate and late-phase reactions were recorded and allergen-specific IgE and IgG subclass responses were determined by CAP radioallergosorbent test and ELISA, respectively. RESULTS: Atopic persons without birch pollen allergy and nonatopic individuals did not have skin reactions to rBet v 1 wild-type and genetically engineered hypoallergenic derivatives. By intradermal testing, 8 of 23 and 13 of 23 birch pollen-allergic patients did not react with the highest concentration (1 microg/mL) of the rBet v 1 fragment mix and rBet v 1 trimer, respectively, compared with 1 with rBet v 1 wild type. Likewise, the highest concentration (100 microg/mL) of fragment mix or trimer failed to elicit a positive skin prick test in 18 of 23 and 15 of 23 patients in comparison with 0/23 with the monomer. No late reactions were observed. CONCLUSION: The recombinant hypoallergenic birch pollen allergens can probably be used for patient-tailored immunotherapy with a reduced risk to induce anaphylactic reactions.

Adolescent↗

Natural history of hay fever and pollen sensitization, and doctors' diagnosis of hay fever and pollen asthma in German schoolchildren.

BACKGROUND: In order to prevent pollen asthma by immunotherapy it is mandatory to know the best time to initiate it. Children with hay fever complaints are at considerable risk of developing pollen asthma. Population-based data on their natural history is urgently needed. METHODS: A longitudinal cohort study was conducted over four years in six rural towns in Baden-Württemberg, Germany. A questionnaire with questions taken from the International Study of Asthma and Allergies in childhood (ISAAC) was filled in every spring and autumn. Hay fever complaints, asthma defining symptoms and new doctors' diagnosis of hay fever and asthma were recorded. Additionally a skin prick test with pollen allergens was performed every autumn. RESULTS: In 1996, 19.7% of 1101 elementary school children (age: 8.1-9.9 years (5-95%)) were found to be sensitized to pollen and 8.7% had already been diagnosed as having hay fever. In a pooled analysis of 2478 children-summers, children with positive pollen sensitization had a significantly higher risk of developing hay fever symptoms (2.63; 2.17-3.10 odds ratio (OR); 95% confidence interval (CI)) and of being diagnosed as suffering from hay fever (7.88; 4.70-13.20). Furthermore, although their OR for the development of asthma symptoms during the pollen season was 3.88 (2.48-6.07 CI), it was only 0.69 (0.24-2.01 CI) for doctors' diagnosis of pollen asthma. CONCLUSION: Children of elementary school age with pollen sensitization and a history of hay fever are at considerable risk of getting pollen asthma, but they are not quickly diagnosed as such. Specific immunotherapy might be a means of preventing asthma completely in such a situation. Our data helps to estimate the sample size for intervention studies of this kind.

Air Pollutants↗

Tetrad pollen formation in quartet mutants of Arabidopsis thaliana is associated with persistence of pectic polysaccharides of the pollen mother cell wall.

The quartet (qrt) mutants of Arabidopsis thaliana produce tetrad pollen in which microspores fail to separate during pollen development. Because the amount of callose deposition between microspores is correlated with tetrad pollen formation in other species, and because pectin is implicated as playing a role in cell adhesion, these cell-wall components in wild-type and mutant anthers were visualized by immunofluorescence microscopy at different stages of microsporogenesis. In wild-type, callose was detected around the pollen mother cell at the onset of meiosis and around the microspores during the tetrad stage. Microspores were released into the anther locule at the stage where callose was no longer detected. Deposition and degradation of callose during tetrad pollen formation in qrt1 and qrt2 mutants were indistinguishable from those in wild-type. Enzymatic removal of callose from wild-type microspores at the tetrad stage did not release the microspores, suggesting that callose removal is not sufficient to disperse the microspores in wild-type. Pectic components were detected in the primary wall of the pollen mother cell. This wall surrounded the callosic wall around the pollen mother cell and the microspores during the tetrad stage. In wild-type, pectic components of this wall were no longer detectable at the time of microspore release. However, in qrt1 and qrt2 mutants, pectic components of this wall persisted after callose degradation. This result suggests that failure of pectin degradation in the pollen mother cell wall is associated with tetrad pollen formation in qrt mutants, and indicates that QRT1 and QRT2 may be required for cell type-specific pectin degradation to separate microspores.

Arabidopsis↗

Allergens from birch pollen and pollen of the European chestnut share common epitopes.

Type I allergy to pollen of the European chestnut (Castanea sativa) represents a major cause of pollinosis in (sub) Mediterranean areas. Using sera from 14 patients with established allergy to pollen of the European chestnut, 13/14 sera (92%) showed IgE-binding to a 22 kD protein, 2/14 (14%) displayed additional binding to a 14 kD protein and 1/14 (7%) bound only to the 14 kD protein of European chestnut pollen extract. Two monoclonal mouse antibodies, BIP 1 and BIP 4, directed against different epitopes of Bet v I (the major birch pollen allergen), and a rabbit antibody to recombinant birch profilin (rBet v II) were used to characterize the proteins of the European chestnut pollen. The recombinant birch pollen allergens, rBet v I and rBet v II (profilin) were employed to show common allergenic structures on proteins from both birch and European chestnut pollen by IgE-inhibition experiments. Despite the fact that the 22 kD protein displayed a higher molecular weight in comparison to the 17 kD major birch pollen allergen, Bet v I, we could demonstrate reactivity of both monoclonal antibodies, BIP 1 and BIP 4, with this protein. A complete inhibiton of IgE-binding to this 22 kD protein was shown by pre-incubating sera with purified recombinant Bet v I. In addition, the 14 kD protein could be identified by IgE-inhibition studies with recombinant Bet v II and by using a rabbit anti-profilin antibody as the profilin from pollen of the European chestnut.

Allergens↗

Honeybee interference as a novel aid to reduce pollen exposure and nasal symptoms among greenhouse workers allergic to sweet bell pepper (Capsicum annuum) pollen.

BACKGROUND: In 1999, an extensive study among bell pepper growers showed a prevalence of 53.8% work-related symptoms and 35.4% sensitisation to bell pepper pollen. Experiments with bees to remove pollen from bell pepper flowers have been done for a few years. OBJECTIVES: It was the aim of this study to investigate whether bees can reduce the pollen exposure in bell pepper greenhouses and whether this reduction results in a decrease in allergic complaints in the greenhouse workers. METHODS: Eighteen greenhouses were selected for the study. In each greenhouse, pollen exposure was estimated. In 6 and 3 of the greenhouses, high, respectively low, numbers of honeybees were placed throughout the pollen season of the sweet bell pepper plant. Nine greenhouses without honeybees were used as control. At baseline, as well as after 4 and 8 months, nasal symptoms assessed with a visual analogue score and lung function parameters were used as outcome measure. RESULTS: Forty-four of the 133 employees invited reported work-related symptoms. High numbers of bees reduced the pollen amount in a dose-dependent way to 18% of the baseline exposure. A significant trend relationship between the visual analogue scale in nasal symptoms and the number of colonies of bees was seen. CONCLUSIONS: The interference of bees in bell pepper greenhouses significantly reduces the pollen amount. This reduction is associated with less work-related rhinitis symptoms in allergic greenhouse workers. This intervention study supports the hypothesis that allergic work-related complaints of greenhouse workers, sensitised to bell pepper pollen, are caused by occupational exposure to this pollen in the greenhouse.

Adult↗