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At least 991 records · Page 55Linked to original sources
PubMed2000

Stamen development in the Ericaceae. I. Anther wall, microsporogenesis, inversion, and appendages.

Development of the introrse, tetrasporangiate, and normally dorsifixed and poricidal stamens has been studied at the gross morphological and cellular level in ten species of Ericaceae. Microsporogenesis, followed in four species, is normal, with cytokinesis simultaneous, forming tetrahedral tetrads. The tricolp(or)ate pollen is shed as permanent tetrads with each segment two-celled except in Enkianthus in which pollen grains are three-celled monads. Anther-wall development is similar in all four species initially, but no regular pattern of wall development could be recognized thereafter. The tapetum, of parietal origin, is binucleate, glandular, and mainly uniseriate. Viscin threads occur with the tetrads in the three rhododendroid species. A well-developed endothecium appears only in Enkianthus.Soon after stamen initiation, anthers of nine species invert at the eventual filament-anther junction to become introrse; in Enkianthus inversion occurs close to anthesis. Microsporogenesis starts during early inversion; greater cell elongation on the abaxial side of the young anther completes inversion by the late sporogenous-tissue stage. In Erica and, to a lesser extent Calluna, inversion results from greater abaxial than adaxial increase in cell number and length just above the filament-anther junction. The single vascular strand reflects the degree of inversion. Stamens of six species are appendaged; three have only awns, two only spurs, while one has both. Appendages arise from residual meristems after inversion is completed (or almost so) in all except Enkianthus. Awns develop at what will be the apex at maturity of each anther half. Their length and orientation vary among species. Only in Vaccinium do the awns become hollow (tubules). Spurs, varying in length, shape, and size, arise on the abaxial side from the filament, connective, or thecae.

Journal Article↗
PubMed2003

The use of the S haplotype-specific F-box protein gene, SFB, as a molecular marker for S-haplotypes and self-compatibility in Japanese apricot (Prunus mume).

Japanese apricot ( Prunus mume) exhibits the S-RNase-based gametophytic self-incompatibility system as do other self-incompatible Prunus species. This report identifies the S haplotype-specific F-box protein gene ( SFB), a candidate gene for pollen- S, of Japanese apricot, which leads to the development of a molecular typing system for S-haplotype in this fruit species. Both 5'- and 3'-RACE (rapid amplification of cDNA ends) were performed with SFB gene-specific oligonucleotide primers to clone Pm-SFB(1) and Pm-SFB(7) of 'Nanko ( S(1) S(7))'. As in the case of SFB of other Prunus species, Pm-SFB(1) and Pm-SFB(7) showed a high level of S-haplotype-specific sequence polymorphism and their expression was specific to pollen. Genomic DNA-blot analyses of 11 Japanese apricot cultivars with the Pm-SFB probes under low stringency conditions yielded RFLP bands specific to the S(1)- to S(8)-haplotypes as well as a self-compatible S(f)-haplotype. A practical usage of SFB as a molecular marker for S-haplotypes and self-compatibility in Japanese apricot is discussed.

Amino Acid Sequence↗
PubMed2006

Phoenix sylvestris Roxb pollen allergy: a 2-year randomized controlled trial and follow-up study of immunotherapy in patients with seasonal allergy in an agricultural area of West Bengal, India.

BACKGROUND: Although the efficacy of allergen immunotherapy has been demonstrated in seasonal pollen allergy, there is no report of a double-blind placebo-controlled trial with standardized pollen extract in seasonal respiratory allergy from India. In the agricultural area of eastern India, Phoenix sylvestris Roxb or date sugar palm is grown or cultivated and seasonal allergic rhinitis is common during the pollen season. OBJECTIVE: The objective of the present study was to observe the clinical and immunological changes during a 2-year double-blind placebo-controlled trial of immunotherapy with standardized P sylvestris pollen extract in respiratory patients sensitive to pollen from this wild date palm. Thirty-five subjects with typical seasonal allergic rhinitis with or without bronchial asthma were selected. A symptom-medication score (based on a questionnaire and diary) was correlated with pollen counts as recorded in a Burkard sampler. Eighteen subjects were randomized to a specific immunotherapy (SIT) group receiving regular injections containing standardized allergen extract and 17 to a placebo control group. Changes in the level of specific immunoglobulin (Ig) E, IgG1, and IgG4 were recorded at 3-month intervals. Measurement of wheal diameter, total IgE level and forced expiratory volume in 1 second (FEV1) were performed before starting and a month after finishing therapy. RESULTS: The SIT group showed decreases of 33.5% and 57% from the baseline symptom-medication scores during the first and second treatment season, respectively. This group showed significant decreases in skin-reactivity to P sylvestris pollen extract and in specific IgE levels, and significant increases in FEV,, specific IgGI (1.95-3.2 times higher) and IgG4 (21.24-30.83 times higher). There were no significant changes in total IgE levels. The control group showed no significant changes for any parameter except the development of new sensitization in 2 cases (to Saccharum officinarum pollen grain and Alternaria species spores). The rate of local adverse reactions was 0.024%. CONCLUSION: After a 2-year study, allergen immunotherapy with standardized P sylvestris pollen extract was found to be effective in seasonal respiratory allergic subjects susceptible to P sylvestris pollen with a narrow range of sensitization.

Adult↗
PubMed1987

[Use of solid-phase immunoenzyme analysis for determining allergen-specific IgE antibodies].

An ELISA system for the detection of allergen-specific IgE antibodies to ragweed allergen has been developed. The system is highly sensitive and specific. Ragweed pollen allergen has been obtained by the dialysis of water-soluble extract through a kidney membrane. The high molecular fraction of ragweed allergen, showing the whole of the allergenic activity detected by skin tests in untreated patients, has been used for coating polystyrene assay plates. To detect IgE antibodies to ragweed allergen, the conjugate of sheep anti-IgE antibodies with horse-radish peroxidase has been used. The level of allergen-specific IgE antibodies has been determined on the basis of the data on the optical density of the samples in comparison with that of the normal sera. The correlation factor of the results obtained in the assay of specific IgE antibodies with the newly developed assay system and with the commercial kit Phadezyme RAST manufactured by Pharmacia AB (Sweden) has proved to be 0.82 at n = 39, p less than 0.01, while the variation factor in the reproduction of the assay results has proved to be 12% at n = 40.

Adsorption↗
PubMed1992

Cell-cell communication in plants: self-incompatibility in flower development.

Self-incompatibility, a mechanism that prevents self-fertilization in plants, is based on the ability of the pistil to discern the presence of self-pollen and on the female tissue's capacity to inhibit the growth or germination of self-related, but not of genetically unrelated, pollen. As a self-recognition system, self-incompatibility responds to specific cellular products and signals and thus offers a unique system in which to study the components of cellular communication in plants. The cytological manifestations of self-incompatibility have been well studied, and, with the cloning of cDNAs for several proteins associated with this recognition process, a detailed molecular view of self-incompatibility is emerging.

Cell Communication↗
PubMed1987

Multivariate analysis of ambient environmental factors and respiratory effects.

Relationships between respiratory health and environmental conditions (pollen, pollution and meteorology) are investigated in 204 subjects in four symptom groups in four geographical clusters in Tucson. Techniques used are principal components, factor and path analysis. Daily respiratory symptoms and peak expiratory flows were recorded during a three-year period. Ambient pollutants, meteorological conditions and pollen types were monitored in or near the clusters. Factor-based scales, which are climate and season specific, are developed for the environmental variables. Three pollutant/meteorological scales represent 'Summer', 'Winter', and 'Humidity'. Four pollen scales represent early and late spring, summer and fall pollen types. Relationships between environmental variables, respiratory symptoms and peak expiratory flow are analyzed with path diagrams, after accounting for age, sex, smoking habits and stove type. The different effects of the environment on asthmatics, allergics and airways obstructive disease subjects have been demonstrated. Many relationships were found between environmental factors and respiratory responses. The pollutant and meteorological variables are related to respiratory symptoms and peak flow directly as well as through interactions with pollen types. Some of the largest positive coefficients are seen in association with seasonal pollen types, specifically, rhinitis and dyspnoea.

Adult↗
PubMed1999

Allergy to Parietaria officinalis pollen.

Parietaria pollen allergens (officinalis, judaica, lusitanica, creatica) are one of the most common causes of pollinosis in the Mediterranean (Spain, France, Italy, and Croatia). Parietaria has very long period of pollination, often reaching peaks of more than 500 grains/m3 of air at the beginning of June, and very strong allergenic properties. There is a significantly positive correlation for the newcomers between the intensity of the skin test reaction and concentration of specific serum IgE with the length of residence in the area, whereas autochthonous patients show a negative correlation between the age and intensity of hypersensitivity. This suggests that the environment encountered at birth may have a decisive role in the development of allergic respiratory diseases. Due to structurally similar pollen antigens in different Parietaria species, they are all equally useful in diagnosis and treatment of allergy, regardless of the pollen species to which the patient is sensitive or the prevalent species in the area. In our hands, specific immunotherapy with subcutaneous injections of partially purified, characterized, and standardized pollen extract of Parietaria allergen proved effective. It was possible to define an optimal maintenance dose of antigen per injection. During (years of) therapy, we observed an initial increase in total serum IgE concentration and increase in allergen-specific serum IgG blocking antibodies, decrease in allergen-specific serum IgE concentration and amount of histamine released from peripheral blood leukocytes challenged in vitro with the allergen, as well as in symptom and additional medication scores.

Allergens↗
PubMed1981

Increase of lymphocytes with Fc receptors for IgE in patients with allergic rhinitis during the grass pollen season.

Peripheral blood lymphocytes from 10 nonallergic donors and 7 patients suffering from seasonal allergic rhinitis and receiving desensitization therapy were analyzed by rosette assays for Fc receptors for IgE (Fc epsilon R) and IgG (Fc gamma R) before, during and after the grass pollen season. Six of seven patients had moderately elevated IgE levels (330 +/- 268 IU/ml), all had high titers of skin sensitizing antibodies to grass pollens and serum IgE antibodies as measured by radio-allergosorbent tests (RAST). Seven of the nonallergic donors had 2-30 IU/ml IgE and negative RAST, whereas three had 91-267 IU/ml IgE and two were RAST positive to the grass pollens. In March, when the patients were asymptomatic, the mean +/-SD of the Fc epsilon R+ lymphocytes did not significantly differ from the nonallergic control group: nonallergic Fc epsilon R+ 1.2 +/- 0.9% (29 +/- 20/,mm3), allergic Fc epsilon R+ 2.0 +/- 3.1% (48 +/- 52/mm3). In contrast, during the grass pollen season in May and June, when the patients developed symptoms of allergic rhinitis, they had significantly (P less than 0.01) more Fc epsilon R+ lymphocytes than the controls: nonallergic Fc epsilon R+ 1.7 +/- 1.9% (40 +/- 46/mm3), allergic Fc epsilon R+ 4.7 +/- 1.2% (134 +/- 69/mm3). In the postpollen period, August-October, most of the patients again had low numbers of Fc epsilon R+ lymphocytes: nonallergic Fc epsilon R+ 1.4 +/- 0.9% (26 +/- 13/mm3), allergic Fc epsilon R+ 2.1 +/- 1.9% (62 +/- 82/mm3). The nonallergic control donors with elevated IgE levels and positive RAST always had low numbers of Fc epsilon R+ lymphocytes. In contrast, two other nonallergic donors, who had a 2-7 IU/ml IgE and negative RAST, showed significant increases of Fc epsilon R+ lymphocytes over several weeks during the grass pollen season. No statistically significant changes in Fc gamma R+ lymphocytes occurred in both nonallergic and allergic donors. The total and specific IgE serum levels did not vary much in the nonallergic donors and patients during the period of study and any changes that did occur did not correlate with the changes in Fc epsilon R+ lymphocytes. The data demonstrate that Fc epsilon R+ peripheral blood lymphocytes increase in allergic patients during natural antigen exposure and active disease in the absence of measurable increases of total and specific serum IgE. Because two nonallergic control donors also had temporary increases of Fc epsilon R+ lymphocytes, an increase of peripheral blood Fc epsilon R+ lymphocytes may be a sensitive indicator of an ongoing IgE immune response.

Humans↗
PubMedDate not supplied

An algorithm for estimating potential deposition of corn pollen for environmental assessment.

The safety and impact on the environment of transgenic crops are important issues, and studies have shown that pollen from transgenic Bt (Bacillus thuringiensis) corn (Zea mays L.) may kill nontarget insects. To develop an algorithm for assessing the environmental effect of transgenic crops, we arranged a field experiment in Tsukuba, Japan. Pollen dispersal and deposition were measured inside and outside a cornfield throughout the flowering period. Weather conditions such as wind speed and direction were measured at the same time. Pollen dispersal peaked 1 week after the start of flowering and continued for 12 days thereafter. The variation in daily pollen dispersal was similar at all observation points. Both pollen dispersal and deposition decreased exponentially with distance from the cornfield on all days. We estimated potential pollen deposition with a quasi-mechanistic model that incorporates the effects of wind direction, wind speed, and flowering intensity. The daily potential deposition was summed over the flowering period, and then the relationship between distance from the cornfield and the integrated potential deposition was estimated. It was possible to show the effective area of the environmental risk zone posed by genetically modified pollen by combining the distance/deposition relationship with the dose/response relationship derived from a laboratory assay. The algorithm described here can be applied to various wind-pollinated plants to estimate both potential and integrated pollen deposition.

Algorithms↗
PubMed2000

Overexpression of the calcium-dependent protein kinase OsCDPK2 in transgenic rice is repressed by light in leaves and disrupts seed development.

Independent transgenic rice lines overexpressing the rice CDPK isoform OsCDPK2 were generated by particle bombardment. High levels of OsCDPK2 were detected in leaves removed from etiolated plants, as well as in stems and flowers. However, there was no overexpression in green leaves that had been exposed to light, confirming that OsCDPK2 protein stability was subject to light regulation. The morphological phenotype of transgenic plants producing high levels of recombinant OsCDPK2 was normal until the onset of seed development. Flowers developed normally, producing well-shaped ovaries and stigmas, and mature anthers filled with pollen grains. However, seed formation in these plants was strongly inhibited, with only 3-7% of the flowers producing seeds. Seed development was arrested at an early stage. We discuss these data with respect to the possible requirement for specific CDPK isoforms during rice seed development.

Calcium-Binding Proteins↗
PubMed1984

Estimation of mating system parameters when outcrossing events are correlated.

Many plant species have mating systems characterized by a mixture of self-fertilization and outcrossing. Statistical estimation of the outcrossing rate has relied on a model of the mating process that assumes that successive outcross events within a family arise from independent draws of pollen from the total population of male plants. Although this assumption is likely to be most appropriate for wind-pollinated plants, it is not appropriate in certain insect-pollinated plants. An alternative model is developed that assumes that successive outcross events within a family involve pollen drawn from a single male parent. The estimation of the parameters that index this model is outlined and a procedure for calculating the variances of the parameter estimates is presented. Monte Carlo simulations of the sampling processes assumed by each model are also presented. The simulations show that application of the incorrect estimation model to data can lead to a large bias in parameter estimates.

Journal Article↗
PubMed1993

Ovary and Gametophyte Development Are Coordinately Regulated by Auxin and Ethylene following Pollination.

The differentiation and development of ovules in orchid flowers are pollination dependent. To define the developmental signals and timing of critical events associated with ovule differentiation, we have examined factors that regulate the initial events in megasporogenesis and female gametophyte development and characterized its progression toward maturity and fertilization. Two days after pollination, ovary wall epidermal cells begin to elongate and form hair cells; this is the earliest visible morphological change, and it occurs at least 3 days prior to pollen germination, indicating that signals associated with pollination itself trigger these early events. The effects of inhibitors of ethylene biosynthesis on early morphological changes indicated that ethylene, in the presence of auxin, is required to initiate ovary development and, indirectly, subsequent ovule differentiation. Surprisingly, pollen germination and growth were also strongly inhibited by inhibitors of ethylene biosynthesis, indicating that male gametophyte development is also regulated by ethylene. Detailed characterization of the development of both the female and male gametophyte in pollinated orchid flowers indicated that pollen tubes entered the ovary and grew along the ovary wall for 10 to 35 days, at which time growth was arrested. Approximately 40 days after pollination, coincident with ovule differentiation as indicated by the presence of a single archesporial cell, the direction of pollen tube growth became redirected toward the ovule, suggesting a chemical signaling between the developing ovule and male gametophyte. Taken together, these results indicate that both auxin and ethylene contribute to the regulation of both ovary and ovule development and to the coordination of development of male and female gametophytes.

Journal Article↗
PubMed2005

Mammalian sex hormones in plants.

The occurrence of mammalian sex hormones and their physiological role in plants is reviewed. These hormones, such as 17beta-estradiol, androsterone, testosterone or progesterone, were present in 60-80% of the plant species investigated. Enzymes responsible for their biosynthesis and conversion were also found in plants. Treatment of the plants with sex hormones or their precursors influenced plant development: cell divisions, root and shoot growth, embryo growth, flowering, pollen tube growth and callus proliferation. The regulatory abilities of mammalian sex hormones in plants makes possible their use in practice, especially in plant in vitro culture.

Animals↗
PubMed1999

Luminescence immunoassay of pollen allergens on air sampling polytetrafluoroethylene filters.

A new method for quantification of airborne birch and grass pollen allergens collected on porous polytetrafluoroethylene filters has been developed. In this method, the allergens firmly adsorbed to the sampling filter of 25 mm in diameter are reacted with specific antibodies conjugated to alkaline phosphatase, generating a matrix-bound allergen-antibody-phosphatase complex. The filter is then floated on a chemiluminescent enzyme substrate solution. The light intensity of the product is linearly related to the amount of allergen over a large mass range, 0-1000 SQ (1 SQ is about 250 pg of protein). This direct on sampling filter in solution (DOSIS) technique demonstrated intra-assay precisions between 6-16% and 11-15% for the levels of 1-100 SQ units of grass allergen Phl p 5 and 4-400 SQ units of birch allergen Bet v 1, respectively. The limits of quantification for the corresponding allergens were estimated to 0.5 and 2 SQ units. Application of DOSIS to analysis of the grass pollen allergen concentrations of outdoor air for 12 days in July 1998 revealed a correlation coefficient of 0.69 between pollen grain and allergen concentrations for the dry weather period. After rainy days large amounts of grass allergens were present even in the absence of pollen grains.

Air Pollutants↗
PubMed1975

Ragweed pollen generation and sampling methods for filtration studies.

The means of generating and measuring the concentration of ragweed pollen particles for air filtration studies is discussed. The development of an inexpensive in-line impaction type sampler which collects the sample on filter paper is described. The advantages of the total particle count method when using this sampler are also defined. The effect of sampling an air steam without using an isokinetic probe was investigated; a non isokinetic sampling train was found to give results with accuracy comparable to isokinetic data. Another part of the study was to examine the "shadowing" effect of one sampling probe. Means are given for adjusting data for this effect.

Filtration↗
PubMed2006

[Development of the simple method for measurement the content of Cry j 1 in the air by latex agglutination test].

BACKGROUND: In order to develop an easy method for measure the airborne C. japonica pollen allergen (Cry j 1) without any utensils or a special apparatus, we examined latex agglutination test for the purpose. METHODS: The latex beads were reacted with the anti-Cry j 1 polyclonal antibody, and the beads were blocked with bovine serum albumin (sensitized beads). The measurement is as follows; two-fold diluted series of solutions of airborne samples are reacted with the sensitized beads, and the results are examined after 2 hrs. RESULTS: Agglutination was recognized with 5ng/ml Cry j 1 standard solution and 20pg/m3 of airborne samples. CONCLUSION: We have developed a simple method for measure the airborne Cry j 1 by use of latex agglutination test. The strong point of the method is 1) measurement is easy and does not affect the numbers of pollen, 2) do not need any utensils or a special apparatus, 3) measure the disease causative materials themselves.

Air Pollutants↗
PubMed2003

Variation in restorer genes and primary sexual investment in gynodioecious Plantago coronopus: the trade-off between male and female function.

In many gynodioecious species the nuclear inheritance of male fertility is complex and involves multiple (restorer) genes. In addition to restoring plants from the female (male sterile) to the hermaphrodite (male fertile) state, these genes are also thought to play a role in the determination of the quantity of pollen produced by hermaphrodites. The more restorer alleles a hermaphroditic plant possesses, the higher the pollen production. To test this hypothesis I combined the results of crossing studies of the genetics of male sterility with phenotypic data on investment in stamens and ovules among the progeny of plants involved in these studies. The sex ratio (i.e. the frequency of hermaphrodites among the progeny), being a measure of the number of restorer alleles of the maternal plant, was positively related to the investment in pollen (male function), but negatively related to the investment in ovules (female function), in both field and greenhouse experiments. Consequently, a negative correlation between male and female function was observed (trade-off) and it is suggested that antagonistic pleiotropic effects of restorer genes might be the cause. Phenotypic gender, a measure combining investment in both pollen and ovules, was highly repeatable between field and greenhouse, indicating genetic determination of a more male- or female-biased allocation pattern among the studied plants.

Analysis of Variance↗
PubMedDate not supplied

Latitudinal study of allergenic pollen in two Spanish cities.

A comparative study was performed on the pollen spectra in 1990 in two Spanish cities with different vegetation and climate, one situated on the south coast (Huelva) and the other in the north and inland (Palencia). The flowering of Alnus and Fraxinus occurred earlier in the north, while that of grasses (Plantago, Poaceae and Urticaceae) occurred earlier and lasted longer in the south, with milder temperature conditions resulting in no fall in pollen content between winter and spring. The absence of olive pollen in Palencia reaffirms that the pollen spectrum of a locality is a consequence of the surrounding vegetation. The geographical situation of Palencia, in the interior of Spain, results in higher percentages of Poaceae and Quercus. The enormous pollution of Huelva favors the greater development of the Urticaceae family and the greater presence of its pollen in the air.

Allergens↗