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PubMed1999

A novel calcium-binding protein is expressed in Brassica pistils and anthers late in flower development.

We describe the cloning and characterization of PCP, a novel calcium-binding protein that is expressed predominantly in the pistils and anthers of Brassica flowers late in flower development. A PCP cDNA - isolated from a subtracted cDNA library enriched in transcripts present in the pistil late in flower development - potentially encodes a 175 amino acid protein with a calculated molecular weight of 19.1 kDa. Other than limited homology to a repetitive C-terminal polyacidic region of PCP, none of the sequences in the GenBank database shares identity to PCP. This unique protein was purified from an Escherichia coli expression system and shown to bind calcium in a specific manner, both in a protein blot assay and by equilibrium dialysis. PCP binds 29 mol of calcium per mol of PCP protein with an apparent affinity constant of 3.2 x 10(2)/M, values consistent with the presence of a high capacity/low-affinity calcium-binding domain. PCP-specific mRNAs are detected predominantly in the stigma and style of pistils excised from open flowers; much lower levels of expression are seen in anthers of open flowers and in root and leaf tissue. Expression in the pistil steadily increases during flower development and peaks at flower opening. A PCP-specific antibody first detects the protein in pistils at one day prior to flowering, with higher levels of the protein seen in the pistils of open flowers. A low level of the protein is present in anthers of open flowers; however, PCP is not detected in either root or leaf extracts. The pattern of PCP expression is consistent with a possible role for PCP in pollen-pistil interactions or in pistil development. The results are also discussed in light of the central role calcium maintains in pollen tube growth and fertilization.

Amino Acid Sequence↗
PubMed2005

Lethal and sub-lethal effects of spinosad on bumble bees (Bombus impatiens Cresson).

Recent developments of new families of pesticides and growing awareness of the importance of wild pollinators for crop pollination have stimulated interest in potential effects of novel pesticides on wild bees. Yet pesticide toxicity studies on wild bees remain rare, and few studies have included long-term monitoring of bumble bee colonies or testing of foraging ability after pesticide exposure. Larval bees feeding on exogenous pollen and exposed to pesticides during development may result in lethal or sub-lethal effects during the adult stage. We tested the effects of a naturally derived biopesticide, spinosad, on bumble bee (Bombus impatiens Cresson) colony health, including adult mortality, brood development, weights of emerging bees and foraging efficiency of adults that underwent larval development during exposure to spinosad. We monitored colonies from an early stage, over a 10-week period, and fed spinosad to colonies in pollen at four levels: control, 0.2, 0.8 and 8.0 mg kg(-1), during weeks 2 through 5 of the experiment. At concentrations that bees would likely encounter in pollen in the wild (0.2-0.8 mg kg(-1)) we detected minimal negative effects to bumble bee colonies. Brood and adult mortality was high at 8.0 mg kg(-1) spinosad, about twice the level that bees would be exposed to in a 'worst case' field scenario, resulting in colony death two to four weeks after initial pesticide exposure. At more realistic concentrations there were potentially important sub-lethal effects. Adult worker bees exposed to spinosad during larval development at 0.8 mg kg(-1) were slower foragers on artificial complex flower arrays than bees from low or no spinosad treated colonies. Inclusion of similar sub-lethal assays to detect effects of pesticides on pollinators would aid in development of environmentally responsible pest management strategies.

Animals↗
PubMedDate not supplied

Eustachian tube dysfunction in children with ragweed hayfever during natural pollen exposure.

The role of upper respiratory allergy in the pathogenesis of otitis media with effusion (OME) is an interesting but still unresolved issue. In order to investigate this further, fifteen children with ragweed hayfever were studied for the development of eustachian tube obstruction (ETO), utilizing the nine-step pressure-swallow test, prior to, during, and after seasonal exposure to ragweed pollen. Daily symptom-medication diaries were maintained and serial physical examinations were performed. ETO was found in 60% of the ragweed sensitive children during natural pollen exposure. The development of ETO was found to correlate with ragweed skin test wheal size and daily patient symptom-medication scores (SMS) during pollen exposure. Treatment of hayfever symptoms with pseudoephedrine and/or chlorpheniramine did not prevent most patients from developing ETO. Despite the prevalence of ETO in the study group, only one child developed evidence of middle ear effusion. These findings suggest that children with ragweed hayfever develop eustachian tube (ET) dysfunction during natural pollen exposure. Seasonal allergy induced ETO is not, however, by itself sufficient to produce middle ear effusion.

Child↗
PubMed1997

Foraging currencies for non-energetic resources: pollen collection by bumblebees

Animals sometimes forage for resources whose benefits are not energy-based. In such cases, the benefits and costs of foraging cannot be directly compared, making it difficult to evaluate the currency of fitness maximized by the animal's behaviour. For bees, pollen represents such a resource, because they collect pollen as the sole protein source for developing larvae, rather than as a source of energy. This study compared three currencies that could be maximized during pollen collection by bumblebees (Bombus spp.) foraging on different lupin species (Lupinus spp.): pollen collected per inflorescence, pollen collection rate (gross benefits/time) and pollen collection efficiency (gross benefits/costs). Bees visiting lupin inflorescences begin foraging low on an inflorescence and then move upward through a gradient of increasing pollen availability. To maximize each currency, we predicted that a bee would begin foraging at a different position along a lupin inflorescence, depending on the relative influences of the time and energy costs associated with handling flowers and flight. Based on comparisons of observed and predicted starting positions for seven situations, maximization of gross pollen-collection efficiency predicted observed behaviour better than either pollen collected per inflorescence or gross rate of pollen collection. Such maximization of pollen-collection efficiency would enhance a bee's lifetime input of pollen to her colony, as has been demonstrated for nectar-collecting bees. Hence, the economics of foraging for non-energetic resources do not differ qualitatively from foraging for energy.Copyright 1997 The Association for the Study of Animal Behaviour1997The Association for the Study of Animal Behaviour

Journal Article↗
PubMed1990

Cellular localization of water soluble, allergenic proteins in rye-grass (Lolium perenne) pollen using monoclonal and specific IgE antibodies with immunogold probes.

A postembedding method has been developed for localizing water soluble allergens in rye-grass pollen. This uses dry fixation in glutaraldehyde vapour, followed by 2,2-dimethoxypropane, prior to a 100% ethanol series leading into embedment in LR Gold. This has allowed the attachment of specific monoclonal antibodies to the allergen, which are themselves probed with specific immunogold labels to the antibodies. Wall and cytoplasmic sites have been identified, representing an improvement of fixation and localization of allergens over previous studies employing polyclonal, broad spectrum antibodies. Rye-grass allergens are labelled in mature pollen grains in the exine (tectum, nexine and central chamber), and in the electron opaque areas of the cytoplasm, especially mitochondria. The allergens are absent from the intine, polysaccharide (P) particles, amyloplasts, Golgi bodies and endoplasmic reticulum. IgE antibodies derived from humans allergic to rye-grass pollen, bind to similar sites in the cytoplasm but only to the outer surface of the pollen grain wall. This method now provides a valuable tool for further developmental studies on the pollen grains, in order to establish the site/s of synthesis of the allergens.

Allergens↗
PubMedDate not supplied

[Clinical diagnostic assay of allergic patients with pollen extract from Parthenium hysterophorous L].

AIMS: There are no antecedents in Cuba of studies developed to prove the efficacy of on allergy test to pollen Parthenium hysterophorus L. OBJECTIVE: Evaluate the allergenic extract pollen Parthenium hysterophorus L elaborated at the reference hospital William Soler City Havana. MATERIAL AND METHODS: We selected 100 patients with a positive clinic history of inhalant allergy and 100 healthy person. All the persons selected were skin prick tested with dillution's of the extract (1:100 and 1:1000 P/V) and positive and negative control. We measured the average diameter of the wheal and the perpendicular diameter, then we calculated the average. We also calculated size of the wheal in the duplicated, which constituted the size of the reaction. We estimated the validity of the test calculating the sensibility and specificity. We used the EPITABLE program to do this. RESULTS: The skin prick tested positive in 79% of the patients and 9% in the healthy persons, for a sensitivity of 79% the interval of confidence (IC), 69.5, 86.2 and specificity of 91%, IC 83.2, 95.5, the predictive positive value 89.8% IC 81.04, 94.9 and the predictive negative value 81.3%, IC 72.5, 87.8. CONCLUSIONS: The allergenic extract of Parthenium hysterophorus L in very sharp to test the allergy to his pollen produced by the allergology laboratory of Hospital William Soler, is efficacy by diagnostic of the alterations caused by this pollen.

Adolescent↗
PubMed2003

Urticaceae pollen concentration in the atmosphere of North Western Spain.

Plants of the Urticaceae family can develop into a pest on soils enriched with nitrogen. Urticaceae pollen is a biohazard because it elicits severe pollinosis. Pollen grains were sampled by using a Lanzoni seven-day-recording trap from February 1995-December 2000 in the atmosphere of the city of Ponferrada (Leon, North Western Spain). The Spearman test was used to analyse the statistical correlation between Urticaceae pollen and certain meteorological factors in different main pollination periods. Maximum values are reached in June and July, minimum levels are recorded in January and December. The parameters bearing the greatest positive influence on the occurrence of Urticaceae pollen grains are: temperature (maximum, minimum and mean), humidity (absolute, wet-bulb temperature, dew point and mixing ratio) and south western wind direction; negative parameters are: relative humidity, rainfall and period without wind. The highest correlation coefficients were obtained with temperature and wet-bulb. Absolute humidity and wet-bulb temperature yielded better correlation than relative humidity; hence, these two parameters must be included in this type of study. The use of one main pollination period or another in statistical analysis has an influence on the coefficient value. The behaviour of the pollen grains in the atmosphere during the year also influences the results.

Air Pollutants↗
PubMed1997

A controlled evaluation of the efficacy and safety of loteprednol etabonate in the prophylactic treatment of seasonal allergic conjunctivitis. Loteprednol Allergic Conjunctivitis Study Group.

PURPOSE: To evaluate the efficacy and safety of loteprednol etabonate 0.5% as prophylactic treatment for the ocular signs and symptoms of seasonal allergic conjunctivitis. METHODS: In this randomized, double-masked, placebo-controlled, parallel study, 293 adults with history of seasonal allergic conjunctivitis were treated with either loteprednol etabonate or vehicle (placebo) four times daily, beginning before the onset of the allergy season and continuing for 6 weeks. The primary efficacy measure was a primary composite score (sum of itching and bulbar conjunctival injection scores). Supportive efficacy measures were the investigator global assessment and a secondary composite score (sum of tearing, erythema, chemosis, and discomfort scores), all calculated during the 21-day peak pollen season. RESULTS: The proportion of patients who never developed moderate or severe signs and symptoms of allergy during the peak pollen season in the loteprednol etabonate treatment group was greater than that in the placebo group. For the primary composite score, this efficacy criterion was reached by 94% of patients (136/145) in the loteprednol etabonate group and 78% of patients (111/143) in the placebo group (P = .001). The magnitude of effect was similar for the investigator global assessment (86% [118/138] vs 64% [87/137]; P < .001) and, although not statistically significant, the secondary composite score (77% [112/145] vs 68% [97/143]; P = .092). None of the loteprednol etabonate-treated patients had an intraocular pressure increase of 10 mm Hg or more, whereas two placebo patients did. CONCLUSIONS: Loteprednol etabonate is generally effective in prophylaxis of seasonal allergic conjunctivitis and has an acceptable safety profile.

Adolescent↗
PubMed1994

The S-ribonuclease gene of Petunia hybrida is expressed in nonstylar tissue, including immature anthers.

To determine the ability of isolated S-locus promoter sequences to direct organ-specific gene expression, we used microprojectile bombardment to introduce chimeric S-allele/beta-glucuronidase genes into different tissues of Petunia hybrida for transient expression. Histochemical staining showed that S-locus/beta-glucuronidase fusions were expressed in pistil, ovary, and petal tissue. No expression of the chimeric genes was detected in leaves or in mature pollen, either by histochemical staining or by fluorescence assays. RNA blot hybridization confirmed that low levels of S-locus mRNA accumulate in petals and ovaries in vivo. Analysis of the expression pattern of S-locus promoter deletions showed that sequences in the immediate vicinity of the TATA box were sufficient to confer qualitatively correct organ-specific expression of beta-glucuronidase. To further investigate the potential for S-ribonuclease expression in pollen, we used the polymerase chain reaction to amplify RNA accumulated in developing anthers. These assays demonstrated that mRNA for the S-ribonuclease accumulates to low levels in developing anthers several days prior to corolla opening and pollen anthesis. We discuss these results in light of current models of self-incompatibility.

Alleles↗
PubMed1997

Fertilization-independent seed development in Arabidopsis thaliana.

We report mutants in Arabidopsis thaliana (fertilization-independent seed:fis) in which certain processes of seed development are uncoupled from the double fertilization event that occurs after pollination. These mutants were isolated as ethyl methanesulfonate-induced pseudo-revertants of the pistillata phenotype. Although the pistillata (pi) mutant has short siliques devoid of seed, the fis mutants in the pi background have long siliques containing developing seeds, even though the flowers remain free of pollen. The three fis mutations map to loci on three different chromosomes. In fis1 and fis2 seeds, the autonomous endosperm nuclei are diploid and the endosperm develops to the point of cellularization; the partially developed seeds then atrophy. In these two mutants, proembryos are formed in a low proportion of seeds and do not develop beyond the globular stage. When FIS/fis plants are pollinated by pollen from FIS/FIS plants, approximately 50% of the resulting seeds contain fully developed embryos; these seeds germinate and form viable seedlings (FIS/FIS). The other 50% of seeds shrivel and do not germinate; they contain embryos arrested at the torpedo stage (FIS/fis). In normal sexual reproduction, the products of the FIS genes are likely to play important regulatory roles in the development of seed after fertilization.

Arabidopsis↗
PubMed2003

Oral immunization with a recombinant major grass pollen allergen induces blocking antibodies in mice.

BACKGROUND: Immunotherapy for the treatment of pollen allergies traditionally involves a series of parenteral injections of a crude pollen extract. Successful application of this treatment results in the development of systemic tolerance to the sensitizing allergens, including the induction of blocking antibodies. OBJECTIVE: We sought to investigate whether oral immunization with a recombinant pollen allergen could induce a systemic immune response, and the production of systemic blocking antibodies in mice. METHODS: C57BL/10 mice were orally administered rLol p 5 or sodium chloride solution via gavage. RESULTS: We report that the oral administration of rLol p 5 induced a systemic immune response, including the induction of both blocking and interspecific cross-reactive antibodies. CONCLUSION: Our results suggest that oral administration of a major grass pollen allergen can induce the development of a systemic immune response including the production of systemic blocking and cross-reactive antibodies, a response that may offer immunological protection upon subsequent allergen exposure.

Administration, Oral↗
PubMed2003

Genetic engineering of pollen allergens for hayfever immunotherapy.

Type I allergy is an immunoglobulin E-mediated disease, representing a major health problem affecting more than 25% of the world's population. Grass, birch and ragweed pollen are a major source of environmental allergen. Specific immunotherapy is clinically proven to be an effective treatment for allergic conditions that involve the administration of crude extracts prepared from natural sources with potential life-threatening anaphylactic side effects. Recent developments in the molecular biology of pollen allergens have made it possible to design novel therapeutic approaches for improved and safer forms of specific immunotherapy. Hypoallergenic forms of major allergens with reduced immunoglobulin E epitopes have been produced using genetic engineering, whilst preserving other characteristics of the molecule that are able to induce a protective response. These modified forms are expected to make allergen-specific immunotherapy more widely used.

Administration, Oral↗
PubMed2002

Two-generation analysis of pollen flow across a landscape. IV. Estimating the dispersal parameter.

The distance of pollen movement is an important determinant of the neighborhood area of plant populations. In earlier studies, we designed a method for estimating the distance of pollen dispersal, on the basis of the analysis of the differentiation among the pollen clouds of a sample of females, spaced across the landscape. The method was based solely on an estimate of the global level of differentiation among the pollen clouds of the total array of sampled females. Here, we develop novel estimators, on the basis of the divergence of pollen clouds for all pairs of females, assuming that an independent estimate of adult population density is available. A simulation study shows that the estimators are all slightly biased, but that most have enough precision to be useful, at least with adequate sample sizes. We show that one of the novel pairwise methods provides estimates that are slightly better than the best global estimate, especially when the markers used have low exclusion probability. The new method can also be generalized to the case where there is no prior information on the density of reproductive adults. In that case, we can jointly estimate the density itself and the pollen dispersal distance, given sufficient sample sizes. The bias of this last estimator is larger and the precision is lower than for those estimates based on independent estimates of density, but the estimate is of some interest, because a meaningful independent estimate of the density of reproducing individuals is difficult to obtain in most cases.

Alleles↗
PubMed1991

Asteraceae aeropollen of the western United States Gulf Coast.

Volumetric air sampling was performed near Corpus Christi, Texas during 1988 and supplemented with data from 1987 and 1989. Frequencies of captured pollen grains of Parthenium hysterophorus, Ambrosia and allied genera, Helianthus, and other Asteracea were examined. Asteraceous aerospora in 1988 accounted for 22.1% of all pollen found, of which 83.4% were pollen of Ambrosia, 12.4% of Parthenium, and the remainder (4.1%) representative of other genera. Capture of native Ambrosia species and P. hysterophorus peaked in September and October in 1987 and 1988, but Parthenium pollen was also found year round with a smaller secondary peak during May, 1988 and 1989. In the winter a different Ambrosia pollen was captured which compared with A. hispida found in the Yucatan Peninsula and southern Florida at a time when no ragweed was flowering in the vicinity of Corpus Christi. Such a pollen capture probably represents long distance dispersal (ca. 600 miles, 965 km) on strong easterly to southerly prevailing winds. Pollen capture occurred most frequently during daylight hours when percent relative humidity was lower and near midnight when inversions occur. Comparison of pollen capture with meteorologic data demonstrated that photoperiodic responses probably account for the initiation and termination of Ambrosia flowering, and to some extent that of Parthenium, and not sharply lowered temperatures or frost for ending pollen release. Previous plant surveys have shown that P. hysterophorus is more common in the Corpus Christi area than species of Ambrosia, or any other Asteraceae, even though ragweed pollen capture proved 6.9 times greater. This disparity is most likely due to limited long distance dispersal of Parthenium pollen, less pollen produced per another, and a less developed mechanism of wind pollination (passive dispersal or amphiphilous). Since both Parthenium and Ambrosia are significant allergenic plants, correlations between airborne pollen of Parthenium and allergic potential suggest that a prolonged pollination season and perhaps increased allergenicity of unique Parthenium pollen proteins allow Parthenium to be a major allergen despite significantly less ambient pollen.

Air Pollution↗
PubMed2004

Identification of peptides containing T-cell epitopes of Japanese cedar (Cryptomeria japonica) pollen allergen (Cry j 1) in dogs.

Japanese cedar (Cryptomeria japonica, CJ) pollen has been known to cause atopic dermatitis in dogs in Japan. However, since the mechanism of the CJ antigen recognition is not well understood in dogs, it is difficult to develop effective immunotherapy for atopic dermatitis caused by sensitization to CJ pollen. In order to aim at development of a peptide immunotherapy, we tried to identify T-cell epitopes of a major allergen of CJ pollen, Cry j 1, in dogs sensitive to CJ pollen allergen. Peripheral blood mononuclear cells (PBMCs) obtained from 22 dogs experimentally sensitized to CJ pollen allergen and 5 atopic dogs sensitive to CJ pollen allergen were used for mapping of T-cell epitopes of Cry j 1 using 35 kinds of synthesized overlapping peptides of Cry j 1. Reactive peptides were identified based on the results of blastogenic responses of PBMCs against the peptides when the stimulation indices were beyond 2.0. Three reactive peptides were identical in a relatively high population of experimental dogs, which were Nos. 8 (p71-90) (41%), 10 (p91-110) (50%), and 11 (p101-120) (41%). It was considered that these synthesized peptides should contain T-cell epitopes of Cry j 1 in the dogs. However, there were no reactive peptides identical among the five atopic dogs spontaneously sensitive to CJ pollen. The population of dogs experimentally sensitized to CJ pollen antigen will be used in order to investigate effects of a peptide immunotherapy using the reactive peptides. The results in atopic dogs sensitive to CJ pollen antigen will also provide useful information on necessity to develop a tailor-made immunotherapy using reactive peptides in each dog.

Allergens↗
PubMed2001

Developmental and stress regulation of RCI2A and RCI2B, two cold-inducible genes of arabidopsis encoding highly conserved hydrophobic proteins.

The capability of most higher plants to tolerate environmental conditions strongly depends on their developmental stage. In addition, environmental factors have pleiotropic effects on many developmental processes. The interaction between plant development and environmental conditions implies that some genes must be regulated by both environmental factors and developmental cues. To understand their developmental regulation and obtain possible clues on their functions, we have isolated genomic clones for RCI2A and RCI2B, two genes from Arabidopsis ecotype Columbia (Col), whose expression is induced in response to low temperature, dehydration, salt stress, and abscisic acid. The promoters of RCI2A and RCI2B were fused to the uidA (GUS)-coding sequence and the resulting constructs used to transform Arabidopsis. GUS activity was analyzed in transgenic plants during development under both stressed and unstressed conditions. Transgenic plants with either the RCI2A or RCI2B promoter showed strong GUS expression during the first stages of seed development and germination, in vascular bundles, pollen, and most interestingly in guard cells. When transgenic plants were exposed to low temperature, dehydration, salt stress, or abscisic acid, reporter gene expression was induced in most tissues. These results indicate that RCI2A and RCI2B are regulated at transcriptional level during plant development and in response to different environmental stimuli and treatments. The potential role of RCI2A and RCI2B in plant development and stress response is discussed.

Abscisic Acid↗
PubMed2006

Anther-specific expression of mutated melon ethylene receptor gene Cm-ERS1/H70A affected tapetum degeneration and pollen grain production in transgenic tobacco plants.

To develop a new system for inducible male sterility without any modification of the floral architecture in tobacco plants, a mutated ethylene receptor gene Cm-ERS1/H70A was fused either to the tobacco Nin88 promoter known to function mainly in the tapetum and microspore or to the CaMV 35S promoter known to be a constitutive promoter. The fusion genes pNin88::Cm-ERS1/H70A and p35S::Cm-ERS1/H70A were introduced in tobacco plants, which generated two independent transformants. Transformants with 35S::Cm-ERS1/H70A produced less normal pollen and had modified floral architecture while those with Nin88::Cm-ERS1/H70A produced less normal pollen without modification of floral architecture. Histological observations of anthers at stage 2 showed that tapetum degeneration in NH70A #8 and H70A #2 transformants occurred later than in wild types, strongly indicating that the expression of the mutated gene was involved in this delay. These results suggest that the tapetum-specific expression of a mutated ethylene receptor gene is a potential strategy for inducing male sterility in transgenic plants.

Cucurbitaceae↗
PubMedDate not supplied

[Clinico-diagnostic trial in adults allergic to pollen extracts from Cynodon dactylon (L). Pers].

BACKGROUND: There are no antecedents in Cuba of studies developed to prove the efficacy of on allergy test to pollen Cynodon dactylon (L) Pers. OBJECTIVE: To evaluate the allergenic extract pollen Cynodon dactylon (L) Pers elaborated at the reference hospital William Soler City Havana. MATERIAL AND METHODS: We selected 100 patients of 18 to 50 years with a positive clinic history of inhalant allergy and 100 healthy person. All the persons selected were skin prick tested with dilutions of the extract (1:100 and 1:100 P/V) and positive and negative control. We measured the average diameter of the wheal and the perpendicular diameter, then we calculated the average. We also calculated size of the wheal in the duplicated, which constituted the size of the reaction. We estimated the validity of the test calculating the sensibility and specificity. We used the Epitable program to do this. RESULTS: The skin prick tested positive in 81% of the patients and 11% in the healthy person, for sensitivity of 81% the interval of confidence 71.7, 87.9 (CI) and specificity of 89%, CI 80.8, 94.1; the predictive positive value 88.0%, IC 79.2, 93.6 and the predictive negative value 82.4%, IC 73.6, 88.8. CONCLUSIONS: The allergenic extract of pollen Cynodon dactylon (L) Pers is very sharp to test allergy to its pollen produced by the allergology laboratory of Hospital William Soler, and is effective in diagnosing alterations caused by this pollen.

Adolescent↗