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At least 343 records · Page 19Linked to original sources
PubMed1998

Development of pollen-induced allergic rhinitis with early and late phase nasal blockage in guinea pigs.

OBJECTIVE AND DESIGN: Development of nasal blockage and sneezing during repeated inhalation challenges with Japanese cedar pollens was evaluated in guinea pigs. SUBJECTS: Male Hartley guinea pigs. TREATMENT: Guinea pigs were sensitized by intranasal instillation of cedar pollen extracts + Al(OH)3 2 times a day for 7 days. The animal was then forced to inhale the pollens for challenge, which was restrictively trapped in the upper airways, once a week. METHODS: Change of specific airway resistance (sRaw), sneezing frequency, and titers of anaphylactic antibodies in the serum were measured after each of the 30 challenges. RESULTS: At the first challenge, no obvious increase in sRaw was observed. However, the second and third challenges to the animals caused modest biphasic elevations of sRaw, with peaks at the first and the fourth to sixth hour. At the fourth to tenth challenges, marked elevations of sRaw were observed. However, with repetition of the inhalation challenge, the early and the late responses became almost indistinguishable because of partial overlapping as the responses expanded. All guinea pigs sneezed immediately after each pollen inhalation challenge. Apparent increases of both circulating gamma1 and IgE antibodies were seen after the seventh challenge. CONCLUSIONS: These results indicate that the experimental allergic rhinitis established in the present study can be a valuable model for analyzing the pathogenesis of the disease and developing new therapeutic drugs.

Aluminum Hydroxide↗
PubMed1983

Development of monoclonal mouse antibodies specific for allergenic components in ryegrass (Lolium perenne) pollen.

The development of monoclonal mouse antibodies against ryegrass (Lolium perenne) pollen allergens is described. Hybridoma colonies secreting antibodies specific for allergenic components were detected using an enzyme-linked immunosorbent assay. Positive colonies were cloned and expanded. The pollen components with which the monoclonal antibodies interact were identified and characterised following sodium dodecyl sulphate polyacrylamide gel electrophoresis and electrophoretic transfer to nitrocellulose. In this paper six monoclonal mouse antibodies are described. Three antibodies interact with a single molecule of between 30,000 and 35,000 daltons. One antibody interacts with a component of 16,000 daltons whereas the remaining two antibodies react with more than one component, one reacting with two components at 28,000 and 30,000, and the other with five components having molecular weights between 18,000 and 71,000 daltons.

Animals↗
PubMed2005

In vitro germination and transient GFP expression of American chestnut (Castanea dentata) pollen.

The development of the male reproductive structures of American chestnut (Castanea dentata) is described to advance our understanding of its reproductive behavior. This information has been vital in the development of a strategy to collect pollen grains from male catkins suitable for in vitro germination and transformation experiments. Cutting male catkins into small segments and rolling them over a culture plate resulted in evenly dispersed and large amounts of pollen with minimal unwanted accessory floral parts. To optimize pollen viability, the effect of various storage conditions on in vitro germination was examined. Our results showed that initial storage at 4 degrees C for 2 weeks significantly increased percent germination as compared to freshly collected pollen and those stored directly at -20 degrees C or -80 degrees C. This also means that for long-term storage of American chestnut pollen, the catkins should first be kept at 4 degrees C for a couple of weeks and then at -80 degrees C. The use of pollen grains with high viability is necessary for the transformation of American chestnut pollen. To optimize pollen transformation via particle bombardment, the effects of target distance, target pressure, and pollen developmental stage were examined. Statistical analysis showed that bombardment of ungerminated pollen at 1,100 psi resulted in the highest percent transient GFP expression (4.1%).

Fagaceae↗
PubMed2004

Japanese cedar pollen-specific interleukin-4 production develops immediately after the first exposure to pollens in infants with atopic dermatitis.

BACKGROUND: Japanese cedar pollens (JCPs) spread over most areas of Japan from February to April and cause pollenosis. While IgE synthesis against JCPs starts after age 1, it remains to be clarified when JCP-specific T helper cells acquire the ability to produce IL-4, a cytokine that induces IgE synthesis. OBJECTIVE: This study aimed to clarify when the sensitization of T cells to JCPs develops. METHODS: Peripheral blood mononuclear cells from 153 children with atopic dermatitis (AD) aged 0-15 years were stimulated with a standardized JCP allergen. As parameters of T cell responsiveness, lymphocyte proliferation and the production of IL-4 and IFN-gamma were measured. RESULTS: T cell responses against JCPs were negative before March in infants with AD who had never been exposed to JCPs or who were exposed for less than a month (nine, seven and nine subjects for lymphocyte proliferation, cytokine production and IgE synthesis, respectively). Lymphocyte proliferation distinctly increased in 67.6% (23/34) of infants with AD examined between March and June. JCP-specific IL-4 production was observed in 56.0% (14/25) of infants with AD examined between March and June. Correspondingly, a slight increase in the level of serum JCP-specific IgE antibody was seen in 17.2% (five of 29) of infants with AD examined between April and June. CONCLUSION: These results demonstrate that the sensitization of T cells to JCPs is effectively completed within a few months after the first exposure to JCPs.

Case-Control Studies↗
PubMed2003

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↗
PubMed2003

Asymptomatic skin sensitization to birch predicts later development of birch pollen allergy in adults: a 3-year follow-up study.

BACKGROUND: The skin prick test is the allergologic test of choice, but asymptomatic skin sensitization to aeroallergens is common. However, no data in the literature describe the clinical phenotype of asymptomatic sensitized adults. OBJECTIVE: The purposes of this investigation were to provide a clinical characterization of skin test-positive subjects without symptoms and to ascertain the predictive values of common allergologic tests. METHODS: Asymptomatic adults with positive skin prick test results for birch (n = 15), nonatopic control subjects (n = 25), and birch pollen-allergic patients (n = 6) were followed through use of daily diary cards during 3 consecutive birch pollen seasons. At inclusion and at the 3-year follow-up visit, conjunctival and nasal challenges, intradermal late-phase reaction evaluation, and measurement of specific IgE were performed. RESULTS: Asymptomatic sensitized subjects defined a clinically significant phenotype between nonatopic and allergic subjects in terms of specific IgE levels and susceptibility to conjunctival provocation testing. Sixty percent (n = 9) of the asymptomatic sensitized subjects developed clinical allergy. This was associated with an initial birch skin prick test weal diameter of > or =4 mm, a positive conjunctival provocation test result, and specific IgE of > or =CAP class 2, as well as with the presence of other allergies. Specific IgE of > or =CAP class 2 was 87.5% predictive for allergy development, whereas a negative conjunctival provocation test result was 100% negatively predictive. Nasal provocation testing possessed no additional prognostic information. No changes in clinical phenotype were seen in nonatopic or birch-allergic subjects. CONCLUSION: Asymptomatic skin sensitization is a risk factor for later allergy development. At risk is any subject with target organ sensitivity, an elevated specific IgE level, and/or a skin prick test weal diameter of >4 mm.

Administration, Inhalation↗
PubMed2002

Production of allergenic pollen by ragweed (Ambrosia artemisiifolia L.) is increased in CO2-enriched atmospheres.

BACKGROUND: The potential effects of global climate change on allergenic pollen production are still poorly understood. OBJECTIVE: To study the direct impact of rising atmospheric CO2 concentrations on ragweed (Ambrosia artemisiifolia L.) pollen production and growth. METHODS: In environmentally controlled greenhouses, stands of ragweed plants were grown from seed through flowering stages at both ambient and twice-ambient CO2 levels (350 vs 700 microL L(-1)). Outcome measures included stand-level total pollen production and end-of-season measures of plant mass, height, and seed production. RESULTS: A doubling of the atmospheric CO2 concentration stimulated ragweed-pollen production by 61% (P = 0.005). CONCLUSIONS: These results suggest that there may be significant increases in exposure to allergenic pollen under the present scenarios of global warming. Further studies may enable public health groups to more accurately evaluate the future risks of hay fever and respiratory diseases (eg, asthma) exacerbated by allergenic pollen, and to develop strategies to mitigate them.

Carbon Dioxide↗
PubMed2002

Mortality of pollen grains may result from errors of meiosis: study of pollen tetrads in Typha latifolia L.

In the cattail Typha latifolia the four haploid products of meiosis remain attached and form the flat tetrad of pollen grains. Gametophytic lethals arisen de novo in diploid cells of sporophyte must manifest themselves as pollen tetrads with two dead grains. This could allow to estimate the rate of recessive lethals arresting pollen grain development. We studied pollen samples collected from 44 sprouts in two populations in the vicinity of Novosibirsk. The anomalous tetrads T1, T2, T3, and T4 carrying one, two, three, and four dead grains, respectively, were detected in each sampled individual. The mean frequency of all anomalous tetrads in the two populations was 3.4% and 8.7%. The frequencies of tetrad classes varied widely among the individuals with correlation coefficient up to 0.94, but their ratios remained nearly constant. The majority of anomalous tetrads were presented by T1 and T2 classes (their sum comprising 72.7 and 74.0% in two populations), T1 being a little more abundant. The observed pattern of frequencies of tetrads with dead grains can be explained by errors of male meiosis such as chromosome non-disjunction in both meiotic divisions. The tetrads with two dead pollen grains may result mostly from non-disjunction in anaphase I, and those with one pollen grain from non-disjunction in anaphase II, thus making tetrad analysis ineffective for estimating the rate of gametophytic lethals.

Chromosome Mapping↗
PubMed2006

Towards male sterility in Pinus radiata--a stilbene synthase approach to genetically engineer nuclear male sterility.

A male cone-specific promoter from Pinus radiata D. Don (radiata pine) was used to express a stilbene synthase gene (STS) in anthers of transgenic Nicotiana tabacum plants, resulting in complete male sterility in 70% of transformed plants. Three plants were 98%-99.9% male sterile, as evidenced by pollen germination. To identify the stage at which transgenic pollen first developed abnormally, tobacco anthers from six different developmental stages were assayed microscopically. Following the release of pollen grains from tetrads, transgenic pollen displayed an increasingly flake-like structure, which gradually rounded up during the maturation process. We further investigated whether STS expression may have resulted in an impaired flavonol or sporopollenin formation. A specific flavonol aglycone stain was used to demonstrate that significant amounts of these substances were produced only in late stages of normal pollen development, therefore excluding a diminished flavonol aglycone production as a reason for pollen ablation. A detailed analysis of the exine layer by transmission electron microscopy revealed minor structural changes in the exine layer of ablated pollen, and pyrolysis-gas chromatography-mass spectroscopy indicated that the biochemistry of sporopollenin production was unaffected. The promoter-STS construct may be useful for the ablation of pollen formation in coniferous gymnosperms and male sterility may potentially be viewed as a prerequisite for the commercial use of transgenic conifers.

Acyltransferases↗
PubMed2001

The development of a pollen information system for the improvement of QOL.

The Kochi Prefecture Japanese Cedar and Cypress Pollen Information System (P-Net Kochi) was established in 1991 on the initiative of the Pharmaceuticals and Sanitation Division to improve the quality of life of people in Kochi Prefecture, particularly patients with pollinosis. Kochi Prefecture has the highest forests percentage (84%) in Japan. In addition, 40% of the population of the prefecture is concentrated in Kochi City. The average pollen count at 10 observation points an one year was about 20,000/cm2 during the observation period, but it exceeded 110,000/cm2 in 1995, when it was also high nationwide. Kochi Prefecture organized a system to promote people's understanding of pollinosis in connection with environmental problems, and to enlighten people on appropriate preventive measures. The system has been improved in the rapid and efficient transmission of information over the years with technological advances. The introduction of an automatic monitoring system not dependent on human labor and the support of the users proved to be indispensable for the maintenance of the system.

Air Pollution↗
PubMed2006

The protein kinase genes MAP3K epsilon 1 and MAP3K epsilon 2 are required for pollen viability in Arabidopsis thaliana.

We have used reverse-genetic analysis to investigate the function of MAP3K epsilon 1 and MAP3K epsilon 2, a pair of closely related Arabidopsis thaliana genes that encode protein kinases. Plants homozygous for either map3k epsilon 1 or map3k epsilon 2 displayed no apparent mutant phenotype, whereas the double-mutant combination caused pollen lethality. Transmission of the double-mutant combination through the female gametophyte was normal. Tetrad analysis performed using the Arabidopsis quartet mutation demonstrated that the pollen-lethal phenotype segregated at meiosis with the map3k epsilon 1;map3k epsilon 2 genotype. We used transmission electron microscopy to determine that double-mutant pollen grains develop plasma membrane irregularities following pollen mitosis I. Analysis of the subcellular localization of a yellow fluorescent protein (YFP):MAP3Kepsilon1 fusion protein using confocal microscopy and biochemical fractionation indicated that a substantial portion of the MAP3Kepsilon1 present in Arabidopsis cells is localized to the plasma membrane. Taken together, our results suggest that MAP3Kepsilon1 is required for the normal functioning of the plasma membrane in developing Arabidopsis pollen.

Arabidopsis↗
PubMed1999

The AtSUC1 sucrose carrier may represent the osmotic driving force for anther dehiscence and pollen tube growth in Arabidopsis.

The Arabidopsis AtSUC1 protein has previously been characterized as a plasma membrane H+-sucrose symporter. This paper describes the sites of AtSUC1 gene expression and AtSUC1 protein localization and assigns specific functions to this sucrose transporter in anther development and pollen tube growth. RNase protection assays revealed AtSUC1 expression exclusively in floral tissue, which was confirmed by analyses of AtSUC1 promoter-beta-glucuronidase (GUS) plants. In situ hybridizations identified AtSUC1 expression in anther connective tissue, in funiculi and in fully developed pollen grains. Indirect immuno-fluorescence analyses with anti-AtSUC1 antiserum confirmed AtSUC1 protein localization in the connective tissue and funiculi. In mature pollen grains, however, despite high AtSUC1 mRNA levels no AtSUC1 protein was found. Only after pollination of stylar papillae was AtSUC1 protein detected inside the pollen and later inside the growing pollen tubes, suggesting a translation of pre-existing AtSUC1 mRNA after pollination. Pollen germination analyses underlined the important role of sucrose for pollen tube growth. The data presented suggest a role of AtSUC1 in the controlled dehiscence of Arabidopsis anthers. It is postulated that an important function of AtSUC1 is the cell-specific modulation of water potentials.

Amino Acid Sequence↗
PubMed2005

The Oryza sativa no pollen (Osnop) gene plays a role in male gametophyte development and most likely encodes a C2-GRAM domain-containing protein.

Phenotype screens of Ds insertional lines identified a male sterile Orysa sativa no pollen (Osnop) mutant with a pollen-less phenotype at the flowering stage. The mutant phenotype showed linkage to Ds insertion into Osnop gene region. This mutant contained a deletion of 65 kb chromosomal region at the site of Ds insertion containing 14 predicted genes. Out of these deleted genes, Delegen 5-7, 9-10 were redundant, as two or three copies were present with 100% homology in other regions of rice genome. RT-PCR analysis showed that Delegen 5-7 were expressed not only in wild type plants but also in the mutant plants. In addition to this, Delegen 8-10 transcripts could not be detected under normal growth conditions, and Delegen 12 was expressed only in roots, thus deletion of these genes may not affect the pollen development. Our data and analysis also ruled out the possibility of delegen 1-4, 11, and 13 as candidates contributing to the pollen-less phenotype. Further investigation showed that the delegen 14 was expressed only in late stage of pollen development with the highest expression at the stage of pollen release and germination by RT-PCR, Northern blotting, in situ hybridization, and promoter-GUS transgenic plants. Thus, the delegen 14 gene is the best candidate for Osnop, corresponding to the pollen-less phenotype in the mutant. Our data suggest that delegen 14 may play an important role during late stage of pollen development and its germination. Since the delegen 14 gene has both C(2) and GRAM domains, it can be assumed that this gene cross-links both calcium and phosphoinositide signaling pathways. This is the first report to suggest possible functions for this gene in plant development.

Amino Acid Sequence↗
PubMed2025

Translation Co-factor PABP-interacting protein 11 moonlights as a transcriptional activator to modulate callose synthesis gene expression.

The development of rice fertility is a complex process, which is precisely regulated by numerous genes. In this study, we cloned and characterized OsPAIP11, a PABP-interacting protein that functions as an auxiliary factor in translation initiation. The ospaip11 exhibited multiple defects, including impaired callose synthesis, delayed tapetum apoptosis, and abnormal pollen wall development, which are essentially consistent with the phenotype of the allelic mutant dcet1. Subcellular localization analysis revealed that OsPAIP11 is localized in both the cytoplasm and nucleus. Interestingly, further investigation demonstrated that the RRM2 domain of OsPAIP11 exhibits transcriptional activation activity. Moreover, OsPAIP11 directly binds to the promoter of the callose synthesis-related genes GLUCAN SYNTHASE-LIKE 5 (OsGSL5) and OsGAMYB, thereby regulating their transcription and influencing callose biosynthesis during pollen development. Additionally, OsPAIP11 also interacts with the translation initiation factor and auxiliary factors. These findings suggest that OsPAIP11 modulates male fertility primarily by regulating the transcription of callose synthesis-related genes and may also participate in the translation process.

Glucans↗
PubMed2002

Exposure to birch pollen in infancy and development of atopic disease in childhood.

BACKGROUND: The relationship between early allergen exposure, sensitization, and development of atopic disease remains controversial. In 1993, extremely high levels of birch pollen were recorded in Stockholm, Sweden, creating the unique opportunity to study children with different exposures during infancy. OBJECTIVE: We sought to assess the influence of early high-dose exposure to an inhalant allergen (birch pollen) on sensitization and development of atopic disease in children. METHODS: A total of 583 children with atopic heredity born in Stockholm in February through April 1992, 1993, or 1994 were investigated at age 4.5 to 5 years. The children were examined and underwent skin prick testing with inhalant and food allergens. IgE antibodies (RAST) against birch pollen and recombinant birch pollen allergen (rBet v 1) were analyzed in serum. RESULTS: The children born in 1993 (high-dose exposure at 0-3 months) were more often sensitized (ie, positive skin prick test response) to birch pollen than the children born in 1994 (low-dose exposure; 17.8% and 8.8%, respectively; odds ratio [OR], 2.4; 95% CI, 1.2-4.6). A tendency in the same direction was seen for children born in 1992 (high-dose exposure at 12-15 months; OR, 1.7; 95% CI, 0.9-3.2). The results were supported by the RAST analyses. The prevalence of bronchial asthma, allergic rhinoconjunctivitis, and atopic dermatitis did not differ between the birth-year groups. However, the prevalence of pollen- and animal dander-induced allergic asthma was increased in the children born in 1993 (OR, 2.6; 95% CI, 1.2-5.6). An interaction between early high-dose exposure to birch pollen and cat in the household was suggested for sensitization to cat (P =.06). CONCLUSION: Exposure to high levels of birch pollen in infancy increases the risk of sensitization to the same allergen, as well as the risk of allergic asthma.

Air Pollutants↗
PubMed2000

[Forecast of total pollen counts of sugi (Cryptomeria japonica) from the amount of male flower development and the revised total pollen counts].

We have successfully forecast the total pollen counts of sugi (Cryptomeria japonica) since 1996 by the amount of male flower development. The amount of male flower development was observed at 11 forests in the Tanba Mountains and 10 forests in the Chugoku Mountains depending on both in Hyogo Prefecture. The amount of male flower development on each tree was assigned to one of five classes by the number of male flowers per spring. After a large harvest of male flowers, the production of male flowers declined in the following years, especially at high altitudes. It was also followed by a decrease in the number of airborne pollen grains in the later pollen season. According to an analysis of weather conditions, total pollen counts were correlated with the high temperature between July 6 and 20 and the total pollen counts of the previous season. However, the amount of male flower development was the most significant indicator for forecasting total pollen counts. Decrease in total pollen counts due to abnormal weather during the pollen season was correlated with discrepancies in forest flowering time according to observations made in the Rokko Mountains. Increase in total pollen counts was connected by a development of the sugi forest areas. Twenty percent of mature sugi forests from 1992 which showed an annual increase were associated with an increase in total pollen counts. The accuracy of the forecast was improved by revising the total pollen counts for weather conditions during the dispersion stage, a decrease in the production of male flowers at high altitude, and an increase in the production of male flowers connected by a developing forest areas.

Air Pollutants↗