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PubMed1985

Occupational allergy to sunflower pollen.

Although the sunflower belongs to the Compositeae family, allergy to sunflower pollen is not common. The occurrence of occupational allergy to this pollen species made it possible to characterize cross-reactive patterns of Compositeae pollens in a human experimental model. A 24-yr-old man developed rhinitis and conjunctivitis over 5 yr of exposure to sunflower pollens, and asthma developed during the fifth year. All respiratory and occular symptoms disappeared after he was removed from exposure, but he had a food allergic reaction while he was eating honey containing 30% sunflower pollens. The diagnosis of occupational allergy was based on history, skin prick tests and RAST to the pollen. Bronchial provocation tests performed after removal from exposure confirmed the sensitivity to sunflower pollens but there was no nonspecific hyperreactivity. It was found by RAST inhibition that sunflower pollen does not cross-react with other Compositeae pollens tested or with sunflower seed. The honey that elicited food intolerance was demonstrated to inhibit significantly sunflower pollen RAST.

Adult↗
PubMed2006

Localization of group-1 allergen Zea m 1 in the coat and wall of maize pollen.

The pollen surface consists of an outermost coat and an underlying wall. It makes the initial contact with the stigma surface during sexual reproduction. To date, only two proteins have been identified from the maize pollen coat. Zea m 1 (beta-expansin 1) is the major group-1 allergen in maize pollen, but its presence and localization in the pollen coat and wall has not yet been explored. In the present study, immunoblot analysis using an antibody directed against group-1 allergen revealed that a small amount of Zea m 1 exists in the pollen coat fraction prepared using a diethyl ether wash. Immunogold labeling also showed that the extracellular localization of Zea m 1 was mainly restricted to the tectum and the foot layer of the exine (the outer pollen wall), and gold particles immunolabelling Zea m 1 were unevenly dispersed throughout the pollen coat and wall. Moreover, a substantial amount of Zea m 1 was localized in the cytoplasm of the pollen interior. The presence of Zea m 1 in the pollen coat and wall suggests that Zea m 1 may play a potential role in pollen germination on the stigma.

Antigens, Plant↗
PubMed2006

An unusual appearance of a common pollen type indicates the scene of the crime.

Forensic palynology is a useful source of evidence in cases of violence committed in the open. A young girl was grabbed off the street, threatened and brutally raped. During the investigation the exact place of the rape became an issue. Growing around the scene identified by the victim were shrubs identified as Coprosma, a common New Zealand plant and one that produces abundant, easily wind-dispersed pollen. Abundant Coprosma pollen was found at the scene. The pollen were unusual in that the site was very damp, encouraging fungal growth, and fungal hyphae had penetrated the pores of many of the tricolporate pollen grains. Some grains had fungal spores inside. Coprosma pollen identical in preservational characteristics and morphology to those from the scene and containing fungal hyphae and spores were found in considerable numbers on the victim's clothes. This and rare Coprosma pollen grains and fungal remains recovered from vaginal swabs provided evidence that she had been at the scene where she claimed to have been raped. The diversity of pollen types recovered from the clothing in this case provides further evidence of the usefulness of clothing in picking up and retaining pollen from crime scenes and that obvious staining on clothes is not a pre-requisite for good pollen recovery. It also demonstrates the importance of collecting samples from different parts of the same garment in order to get a full picture of events since different parts of a garment can come into contact with different plants or different parts of the ground in a scuffle. It is also demonstrated that significant evidential material can be collected from the body, in this case from vaginal swabs from the victim. Forensic palynology should be considered in every case of violent assault, especially, but not exclusively, when having occurred in an open area subject to extensive pollen settlement.

Adolescent↗
PubMed2004

Nutritional suitability of corn pollen for the predator Coleomegilla maculata (Coleoptera: Coccinellidae).

The nutritional suitability of corn pollen for the facultatively phytophagous predator Coleomegilla maculata was studied in the laboratory. Dry matter, organic matter, ash, crude protein, amino acid, and quercetin contents of pollen from 10 hybrids of field corn were determined. C. maculata were reared on pollen or aphids + artificial diet for their entire lives; larval duration, post-mortem adult dry weights, fecundity within 7 days of mating, and mortality rates were compared among the treatments. In another experiment, C. maculata larvae were reared on pollen; weight gained, pollen ingested, and frass produced were compared among instars. Also, consumption relative to increases in larval biomass and the efficiency with which larvae converted corn pollen into biomass were compared among instars. Beetles reared on aphids had greater weights and fecundity and a shorter larval duration relative to the pollen-fed beetles. The percentages of organic matter and ash in corn pollen were significantly correlated with C. maculata mortality, and we hypothesize that some micronutrient or phytochemical is at sub-optimal levels for C. maculata development in some of the pollens. We observed an increase in the conversion efficiency of pollen and a decrease in the consumption relative to biomass of C. maculata as the larvae aged, which suggests a physiological or behavioral alteration in the feeding behavior of C. maculata during the larval stage.

Animal Feed↗
PubMed2005

From the anther to the proctodeum: Pear (Pyrus communis) pollen digestion in Osmia cornuta larvae.

Modifications of the pollen grains of Pyrus communis Linneaus that occur during the digestion by Osmia cornuta (Latreille) larvae were studied histochemically. We compared the features of the pollen grains found in the anthers, in the larval cell provisions and in the alimentary canal of the 5th instar larvae. Modifications were already evident in the provisions and consisted of protoplast protrusions through the apertures and a decrease in the number of starch-containing pollen grains. After pollen grains were ingested by the larvae, the protoplast appeared retracted from the pollen wall. Pollen digestion began in the anterior part of the midgut, where we observed: (1) disorganised intine at the apertures; (2) disappearance of DAPI staining of nuclear pollen DNA; (3) fewer pollen grains containing starch than in the anthers; (4) some empty pollen grains. Pollen grains in the proctodeum appeared extremely compressed and crushed. Some grains appeared to be unaffected by the digestive process. We hypothesise that the protrusion of the intine and of the protoplast from the apertures in bee provisions could be considered a kind of pre-treatment necessary to initiate the digestion process in the larval alimentary canal.

Animals↗
PubMed2000

In vitro diagnosis of cypress pollen allergy by using cytofluorimetric analysis of basophils (Basotest).

BACKGROUND: Cupressaceae pollen allergy is a worldwide pollinosis, but its in vitro diagnosis is notoriously difficult. The Basotest is a newly available in vitro test for the detection of allergen-specific IgE based on the level of cellular activation of basophils by using flow cytometry. OBJECTIVES: The Basotest was compared with the measurement of cypress pollen-specific IgE in highly selected patients. METHODS: We analyzed 34 patients allergic to cypress pollen selected on the basis of a suggestive clinical history and positive skin test and nasal challenge responses to cypress pollen extract. We also analyzed 8 patients with positive skin test responses to cypress pollen extract who did not present symptoms during the pollen season (intermediate group) and 33 control subjects. Sensitivity, specificity, and efficiency of the Basotest and serum-specific IgE levels measured by using the CAP System were determined in patients allergic to cypress pollen. Histamine release was studied in a selected group of patients. RESULTS: The Basotest was more sensitive (91.2%) than the CAP System (76%) for the in vitro diagnosis of cypress pollen allergy. A dose-response curve was observed in basophils obtained from patients allergic to cypress pollen. There were no false-positive results with either test (specificity 100%). The results of the Basotest or those of the CAP System did not correlate with the patients' in vivo threshold sensitivity assessed by skin tests and nasal challenge. CONCLUSIONS: The Basotest was found to be an effective diagnostic test in patients allergic to cypress pollen.

Adult↗
PubMed1995

Allergenic pollen pollinosis in Madrid.

OBJECTIVE: A 15-year pollen count was performed in the atmosphere of Madrid, Spain, to determine the months in which the highest concentrations of allergenic pollens occur. METHODS: Pollen counts were done with a Burkard spore trap (Burkard Manufacturing, Rickmansworth, Herst., U.K.). The results were subsequently compared with results of skin tests in patients with pollinosis born and living in and around Madrid. RESULTS: The highest airborne presence (percent of total yearly pollen counts, mean of counts from 1979 to 1993) was for Quercus spp. (17%); followed by Platanus spp. (15%), Poaceae (15%), Cupressaceae (11%), Olea spp. (9%), Pinus spp. (7%), Populus spp. (4%), and Plantago spp. (4%). The most predominant pollens from January to April are tree pollens (Cupressaceae, Alnus, Fraxinus, Ulmus, Populus, Platanus, and Morus), although these are also abudant in May and June (Quercus, Olea, and Pinus spp.). The grass pollination period shows a double curve: the first peak occurs from February to April (8% of yearly grasses), and the second peak occurs from May to July (90% of yearly grasses). Among allergenically significant weeds, the most notable is Plantago; in contrast, Rumex, Urticaceae, Cheno-Amaranthaceae, and Artemisia spp. have very low concentrations (< or = 2% yearly total pollens). The most significant allergenic pollen is that of grasses, with a prevalence of positive prick test results of 94%, followed by Olea europaea (61%), Plantago lagopus (53%), Platanus hybrida (52%), and Cupressus arizonica (20%). CONCLUSION: The population of Madrid is exposed to high concentrations of allergenic pollen from February to July, although the most intense period is from May to June. Grass pollens are the most important cause of pollinosis in this area.

Adolescent↗
PubMed1996

Identification of a 60 kd cross-reactive allergen in pollen and plant-derived food.

BACKGROUND: Cross-reactive IgE antibodies were found to be responsible for allergic reactions in patients allergic to pollen on ingestion of food (oral allergy syndrome). So far, the major birch pollen allergen Bet v 1 and birch profilin (Bet v 2) were identified as relevant cross-reactive allergens. OBJECTIVE: In this study we attempted to identify additional cross-reactive plant allergens, which could be responsible for food intolerance in patients allergic to pollen. METHODS: Monoclonal antibodies specific for the major mugwort pollen allergen, Art v 1, representing a 60 kd glycoprotein, were used to detect cross-reactive allergens in other pollens and plant-derived food. The amino acid compositions of the cross-reactive structures were determined, and their resistance against trypsin treatment was investigated. In addition, IgE immunoblot inhibitions were done with the 60 kd mugwort pollen allergen. RESULTS: Monoclonal antibodies specific for the major mugwort pollen allergen, Art v 1, cross-reacted with proteins of comparable molecular weight in fruit and vegetables. Preadsorption of patients' sera with the 60 kd mugwort allergen led to a reduction of IgE binding to components of a similar molecular weight present in different pollen (birch, timothy grass), fruit (apple, peanuts), and vegetable (celery) extracts and reduced IgE binding to apple, kiwi, and celery as determined by RAST inhibitions. CONCLUSION: A cross-reactive plant panallergen, possibly identical to the major mugwort pollen allergen, Art v 1, is described. The allergen represents a protein of approximately 60 kd present in various pollen and plant foods; which is distinct from Bet v 1 and profilin and hence may represent a novel cross-reactive allergen in the oral allergy syndrome.

Allergens↗
PubMed1999

Molecular cloning and characterization of a birch pollen minor allergen, Bet v 5, belonging to a family of isoflavone reductase-related proteins.

BACKGROUND: Birch pollen is a major cause of pollinosis and is responsible for cross-reactive oral allergies to fruits, nuts, and vegetables. The major allergen, Bet v 1, has been extensively characterized, and 3 minor allergens, Bet v 2, Bet v 3, and Bet v 4, have been cloned and sequenced. Recently, another birch pollen protein with an apparent mass of 35 kd was described as a new IgE-binding protein in birch pollen with cross-reacting homologues in plant foods. OBJECTIVE: The aim of this study was to determine the primary structure of the 35-kd birch pollen allergen and to investigate its immunologic properties. METHODS: On the basis of a known complementary DNA fragment, a PCR strategy was applied to obtain the full-length nucleotide sequence of the coding region. The protein was expressed as His-Tag fusion protein in Escherichia coli and purified by Ni-chelate affinity chromatography. Nonfusion protein was obtained by cyanogen bromide treatment of the fusion protein. IgE-binding characteristics and potential allergenicity were investigated by immunoblot, immunoblot inhibition analysis, rat basophil leukemia-cell mediator release assay, and basophil histamine release and compared with those of natural (n) Bet v 5, recombinant (r)Bet v 1, and rBet v 2. RESULTS: Recombinant Bet v 5 has a mass of 33 kd, an isoelectric point of 9.0, and sequence identity of 60% to 80% to isoflavone reductase homologue proteins from various plants. On immunoblots the recombinant Bet v 5 bound IgE from 9 (32%) of 28 sera from patients allergic to birch pollen with a CAP class of at least 3; Bet v 1 was detected by 89% of these patients. IgE immunoblot and inhibition experiments showed that nBet v 5 and rBet v 5 shared identical epitopes. A rabbit antiserum raised against pea isoflavone reductase and patients' IgE reacted with Bet v 5 and proteins of similar size in several vegetable foods, including exotic fruits. A similar reaction pattern was obtained with 2 Bet v 5-specific mAbs. Furthermore, Bet v 5 triggered a dose-dependent mediator release from rat basophil leukemia 2H3 cells passively sensitized with murine anti-birch pollen IgE and from basophils of a Bet v 5-reactive subject with birch pollen allergy. In contrast, no mediator release could be induced from basophils of a subject who was monosensitized to Bet v 1. CONCLUSIONS: This 33-kd protein, designated as Bet v 5, is a new minor allergen in birch pollen and may be responsible for pollen-related oral allergy to specific foods in a minority of patients with birch pollen allergy. Amino acid sequence comparison and immunoreactivity to anti-isoflavone reductase serum indicate that Bet v 5 is related to isoflavone reductase, a protein family that is involved in plant defense reactions.

Allergens↗
PubMed2001

IgE reactivity and cross-reactivity to Japanese cedar (Cryptomeria japonica) and cypress (Chamaecyparis obtusa) pollen allergens in dogs with atopic dermatitis.

The natural occurrence of Japanese cedar (Cryptomeria japonica) pollinosis has been reported in dogs with atopic dermatitis. However, the reactivity to Japanese cypress (Chamaecyparis obtusa) pollen allergens in these dogs has not been reported. The present study was designed to investigate the reactivity to Japanese cypress pollen allergens in dogs sensitized to Japanese cedar pollen allergens. In 19 dogs with specific IgE to C. japonica pollen allergen, we measured the specific IgE to C. obtusa pollen allergen and examined the reactivity to the allergen by intradermal test. Of the 19 dogs, 18 had specific IgE to crude and purified major allergens (Cha o 1) of C. obtusa pollen. Most of the dogs showed a positive reaction to C. obtusa pollen allergens in the intradermal test. Allergenic cross-reactivity between Cha o 1 and Cry j 1 (a major allergen in C. japonica pollen) was observed by the ELISA inhibition method. Dogs sensitized to Japanese cedar pollen allergens demonstrate reactivity to Japanese cypress pollen allergens.

Allergens↗
PubMed1996

Cloning and expression pattern of Hor v 9, the group 9 pollen isoallergen from barley.

In this study we report the cloning, sequence, and characterization of Hor v 9 allergen cDNAs from barley (Hordeum vulgare) pollen. Structural homologues of Kentucky bluegrass (Poa pratensis) group 9 pollen allergens were identified in a cDNA library of barley pollen expressed mRNAs. The Hor v 9 cDNA clone (hvp9742) contained an open reading frame encoding 313 amino acids which included a putative 27-residue signal peptide and one asparagine sequon for glycosylation. The mRNA corresponding to clone hvp9742 was produced abundantly in pollen during the late stages of anther development. The protein encoded by clone hvp974 was synthesized as a fusion protein in the E. coli expression vector pMAL. Immunoblots using antibodies to this recombinant allergen, rHor v 9, showed that Hor v 9 protein accumulated during pollen development and was produced maximally at pollen maturity. Using these antibodies, we also provide evidence that Hor v 9 protein localized to the extracellular matrix of mature pollen. Southern blots suggested that Hor v 9 allergens exist as multiple isoforms in barley. Sequence comparisons showed that the Hor v 9 cDNA clones were also homologous to group 5 allergens of Timothy grass (Phleum pratense) pollen and canary grass (Phalaris aquatica) pollen, and the group 9 allergen of ryegrass (Lolium perenne) pollen.

Allergens↗
PubMed2006

Long distance transport of ragweed pollen as a potential cause of allergy in central Italy.

BACKGROUND: Ambrosia pollen is an important allergen in North America and, as recently discovered, in some European countries. In Italy, the most affected area is the northeast, whereas ragweed has not been reported in the central and southern parts of the country. OBJECTIVE: To identify the source of ragweed pollen detected in Florence and Pistoia in central Italy. METHODS: Ragweed pollen data were collected in Florence and Pistoia for a 6-year period (1999-2004). The relationship between pollen counts and local ground prevalent wind directions was evaluated with analysis of variance and the least significant difference test. Weather conditions were also evaluated on a large-scale circulation pattern by analyzing weather maps and air mass back trajectories. RESULTS: A highly statistically significant relationship between daily prevailing wind direction and pollen count was found in the period under investigation; the ragweed pollen peaks were recorded when winds from northeast in Florence and north-northeast in Pistoia were observed. The synoptic weather situation and the path of back trajectories suggest an area around southern Hungary as a possible source of Ambrosia pollen. Furthermore, the pollen count was above the clinical threshold several times in both Florence and Pistoia. CONCLUSIONS: Several factors indicate that the detection of ragweed pollen in central Italy is due to long distance transport. Taking into consideration the high allergenicity of Ambrosia pollen, the present findings, if confirmed, suggest that the number of sensitized individuals might significantly increase in the near future.

Ambrosia↗
PubMed1999

Effect of tree and grass pollens and fungal spores on spring allergic rhinitis: a comparative study.

BACKGROUND: Current literature indicates tree pollen is less important than grass pollen as the cause of spring allergic rhinitis. The role of fungal spores is secondary and uncertain. OBJECTIVE: To assess the relative allergenicity of tree and grass pollen and fungal spores as the cause of spring allergic rhinitis in central Indiana. METHODS: (1) Chart review of 189 Indiana natives with seasonal allergic rhinitis to ascertain clinical sensitivity to tree or grass pollens. (2) A prospective study conducted in the spring of 1997 in 51 patients, correlating patients' symptom and medication scores with daily pollen and spore counts, obtained with a Burkard spore trap. RESULTS: One hundred thirty of 189 patients (69%) reported symptoms before May with positive prick test to at least one tree pollen. One hundred thirty-four patients (71%) had symptoms in May and June with positive test to grass pollen. The ratio between the two groups is 1:1, in contrast to a ratio of 1:4 derived from the literature. The prospective study revealed a symptom score increase parallel to the rise of tree pollen counts beginning in mid-March and reaching a plateau in early May prior to the onset of grass season. Medication use continued to increase and peaked at the height of grass pollination. Spore counts increased in late May and stayed at high levels throughout June, yet symptom and medication scores steadily declined following the peak of grass pollination in early June. CONCLUSIONS: This study suggests that in central Indiana, tree pollen is more important as the cause of spring allergic rhinitis than that suggested by the literature. This study confirmed previous observations that fungal spores are substantially less allergenic than pollens.

Adolescent↗
PubMed1997

Yearly and seasonal changes of specific IgE to japanese cedar pollen in a young population.

BACKGROUND: There have been no detailed long-term observations of the relationship between specific IgE production and stimulation by various naturally occurring allergens. OBJECTIVE: This study was conducted to elucidate the yearly and seasonal changes of specific IgE antibody production to Japanese cedar pollen, an allergen of Japanese cedar pollinosis, in young adults. METHODS: The number of Japanese cedar pollen were counted over a period of 9 years. Changes in the percentages of antibody carriers to Japanese cedar pollen and mite were examined during these years. Changes in Japanese cedar pollen-specific IgE levels between a low exposure year and a high exposure year in individual subjects were also investigated. RESULTS: From 1987 to 1995, the percentages of Japanese cedar pollen-IgE carriers varied from about 30% to 50% with the intensity of pollen stimulation, and carriers tended to increase yearly. The rates of anti-mite IgE carriers changed little. In the spring which is the pollen season, Japanese cedar pollen-IgE levels in low exposure years were weaker than those in high exposure years in individual subjects. Levels in autumn, which is not the pollen season, showed equivalent levels in both high and low exposure years. Anti-mite IgE levels in individual subjects varied little during these years. CONCLUSIONS: A long-term follow-up study supported that Japanese cedar pollen-IgE production is mainly associated with the degree of allergen exposure.

Adolescent↗
PubMed2000

Preseasonal local allergoid immunotherapy to grass pollen in children: a double-blind, placebo-controlled, randomized trial.

BACKGROUND: We assessed the efficacy of preseasonal local allergoid immunotherapy in a group of children with asthma and/or rhinitis and/or rhinoconjunctivitis due to grass pollen. METHODS: We randomly assigned 24 children allergic to grass pollen to receive local allergoid immunotherapy for 3 months before the pollen season and 24 such patients to receive identically appearing placebo. The immunotherapy consisted of tablets of monomeric allergoid grass pollen allergens held in the mouth until they dissolved and then swallowed. The study was double-blind. Symptoms and medications were scored on diary cards during the pollen season. Nasal eosinophil cationic protein levels were measured by the monoclonal antibodies EG1 and EG2 outside the pollen season and at low and at high pollen concentration during the pollen season. RESULTS: The active-treatment group had a statistically significant reduction of total symptoms (P<0.05), especially bronchial symptoms (P<0.05), in comparison with the placebo group. Immunotherapy was well tolerated and compliance was good. Nasal levels of EG2 and EG1 increased significantly during the pollen season, but there was no difference between groups. EG2/EG1 increased significantly only in the placebo group during natural allergen exposure (P<0.01). CONCLUSIONS: Our results suggest that this immunotherapy is effective for the treatment of asthma due to grass pollen in children.

Administration, Oral↗
PubMed2002

Privet pollen (Ligustrum sp.) as potential cause of pollinosis in the city of Cordoba, south-west Spain.

BACKGROUND: Privet pollen rarely accounts for more than 1% of the annual total of daily pollen concentrations measured in a city; however in areas where these trees are widely used as ornamentals the amounts collected may be high enough to cause allergy symptoms. METHODS: Air samples taken with volumetric particle samplers Lanzoni VPPS 1000 (Lanzoni s.r.l., Bologna, Italy) show that there are differences in privet pollen concentrations measured in neighbourhoods with a high incidence of privet trees and in those taken at some distance from the source of emission. RESULTS: The results suggest that differences are due to the short dispersal range of the pollen grains once released from the plant, resulting from both the entomophilous nature of the plant and the large size of the pollen grains. Urban design, moreover, may play an important role in impeding pollen grain dispersion if the air cannot flow freely through long, narrow avenues. Another important consideration is that the last stages of the flowering period of privet overlaps with the flowering period of olive trees, the main allergen in the area. The fact that the two pollen types share common allergens means that there may be a cross-reaction between olive tree pollen and privet pollen. CONCLUSIONS: Privet pollen should be considered as a potential causative agent of local allergy problems in areas where its presence is extensive and is in combination with other allergens.

Air Pollutants↗
PubMed2003

Exposure to high doses of birch pollen during pregnancy, and risk of sensitization and atopic disease in the child.

BACKGROUND: The role of maternal allergen exposure during pregnancy in sensitization and development of atopic disease in the child remains controversial. In the spring of 1993, extremely high levels of birch pollen were recorded in Stockholm, Sweden. In 1994, the corresponding pollen levels were low. The aim of this study was to assess the influence of exposure during pregnancy to high/low doses of birch pollen on the risk of sensitization and development of atopic disease in children. In addition, a comparison was made with children exposed to birch pollen in early infancy. METHODS: Three hundred and eighty-seven children with atopic heredity, born in Stockholm in July-October 1993 or 1994 (mothers exposed during pregnancy), were investigated at age 4.5 years. The children were clinically examined and were skin prick tested (SPT) with inhalant and food allergens. IgE antibodies (RAST) against birch pollen and recombinant birch pollen allergen (rBet v 1) were analysed in serum. A comparison was made with a similar group of children exposed during the same incident, but in the first 3 months of life, in 1993. RESULTS: The children of mothers high-dose exposed during pregnancy in 1993 tended to be more sensitized (SPT > or = 3 mm) to birch pollen than the children with low-dose exposure during the corresponding period in 1994 (7.6 and 4.6%, respectively, OR: 1.7; 95% CI: 0.7-4.1). A similar but weak tendency was seen for positive RAST analyses (> or =0.35 kU/l) against birch pollen and rBet v 1. Children of mothers high-dose exposed during pregnancy were significantly less sensitized to birch pollen than the children high-dose exposed in early infancy (17.9%, OR: 0.4; 95% CI: 0.2-0.7). There was an overall trend towards a slightly increased prevalence of bronchial asthma, allergic rhinoconjunctivitis and atopic dermatitis in the group with mothers high-dose exposed during pregnancy, compared to those with low exposure. CONCLUSION: Exposure of the mother during pregnancy to high levels of birch pollen resulted in a tendency towards increased risk of sensitization to the same allergen and symptoms of atopic disease in children with atopic heredity. Furthermore, our data indicate that exposure of the mother during pregnancy to inhalant allergens is less likely to result in sensitization in the child than exposure of the child in early infancy.

Asthma↗
PubMed2004

Identification of the pollen determinant of S-RNase-mediated self-incompatibility.

Many flowering plants have adopted self-incompatibility mechanisms to prevent inbreeding and promote out-crosses. In the Solanaceae, Rosaceae and Scrophulariaceae, two separate genes at the highly polymorphic S-locus control self-incompatibility interactions: the S-RNase gene encodes the pistil determinant and the previously unidentified S-gene encodes the pollen determinant. S-RNases interact with pollen S-allele products to inhibit the growth of self-pollen tubes in the style. Pollen-expressed F-box genes showing allelic sequence polymorphism have recently been identified near to the S-RNase gene in members of the Rosaceae and Scrophulariaceae; but until now have not been directly shown to encode the pollen determinant. Here we report the identification and characterization of PiSLF, an S-locus F-box gene of Petunia inflata (Solanaceae). We show that transformation of S1S1, S1S2 and S2S3 plants with the S2-allele of PiSLF causes breakdown of their pollen function in self-incompatibility. This breakdown of pollen function is consistent with 'competitive interaction', in which pollen carrying two different pollen S-alleles fails to function in self-incompatibility. We conclude that PiSLF encodes the pollen self-incompatibility determinant.

Alleles↗